WO2024214754A1

WO2024214754A1 - Exterior material for power storage device, method for manufacturing same, and power storage device

Info

Publication number: WO2024214754A1
Application number: PCT/JP2024/014602
Authority: WO
Inventors: 真天野; 育万塩田; 千秋初田; 万結内田; 孝典山下
Original assignee: 大日本印刷株式会社
Priority date: 2023-04-10
Filing date: 2024-04-10
Publication date: 2024-10-17

Abstract

An exterior material for a power storage device, the exterior material being configured from a laminate provided with at least a base layer, a metal foil layer, and a heat-fusible resin layer in the stated order from the outer side. The surface on at least one side of the metal foil layer has a maximum reflected light intensity of 50 or less in a light reception angle range of 0.0-90.0°, measured at every 0.1° of the light reception angle using a variable-angle photometer under the condition of an incident light angle of 60°.

Description

Exterior material for power storage device, manufacturing method thereof, and power storage device

This disclosure relates to an exterior material for an electricity storage device, a manufacturing method thereof, and an electricity storage device.

Various types of electricity storage devices have been developed to date, but in all electricity storage devices, exterior materials are essential components for sealing the electricity storage device elements, such as the electrodes and electrolyte. Traditionally, metallic exterior materials have been widely used as exterior materials for electricity storage devices.

On the other hand, in recent years, with the increasing performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, and the like, there is a demand for electricity storage devices to be more diverse in shape, as well as thinner and lighter in weight. However, the metallic exterior materials for electricity storage devices that have been widely used up until now have the drawback of being difficult to keep up with the diversification of shapes, and there is also a limit to how much they can be made lighter.

Therefore, a film-like laminate in which a base layer, a metal foil layer, an adhesive layer, and a heat-sealable resin layer are laminated in this order has been proposed as an exterior material for an electricity storage device that can be easily processed into a variety of shapes and can be made thin and lightweight (see, for example, Patent Document 1).

In such exterior materials for electricity storage devices, recesses are generally formed by cold forming, electricity storage device elements such as electrodes and electrolyte are placed in the space formed by the recesses, and the heat-sealable resin layer is heat-sealed to obtain an electricity storage device in which the electricity storage device elements are housed inside the exterior material for electricity storage devices.

JP 2008-287971 A

In order to further increase the energy density of the power storage device, it is necessary to form a deep recess in the film-like exterior material to accommodate the power storage device element. However, when forming the recess by molding the film-like exterior material, there is a problem in that cracks and pinholes are likely to occur.

The main objective of this disclosure is to provide an exterior material for an electricity storage device that is composed of a laminate having, from the outside in order, at least a base layer, a metal foil layer, and a heat-sealable resin layer, and that has excellent formability.

The inventors of the present disclosure have conducted intensive research to solve the above problems. As a result, they have discovered that in an exterior material for an electricity storage device composed of a laminate including, in order from the outside, at least a base layer, a metal foil layer, and a heat-sealable resin layer, by setting the maximum reflected light intensity A at a light receiving angle range of 0.0° to 90.0°, which is measured at every 0.1° of light receiving angle with a variable goniophotometer under the condition of an incident light angle of 60°, to a predetermined value or less for at least one surface of the metal foil layer, the maximum reflected light intensity A can be obtained.

The inventors of the present disclosure have also discovered that in an exterior packaging material for an electricity storage device composed of a laminate including, in order from the outside, at least a base layer, a metal foil layer, and a heat-sealable resin layer, by setting the maximum reflected light intensity B at a light receiving angle range of 45.0° to 75.0° inclusive, measured at every 0.1° of light receiving angle with a goniophotometer under the condition of an incident light angle of 60°, to a predetermined value or more for at least one surface of the metal foil layer.

This disclosure was completed through further investigation based on these new findings.

That is, a first aspect of the present disclosure provides the invention of the following aspects.
The laminate includes, in order from the outside, at least a base layer, a metal foil layer, and a heat-sealable resin layer.
The exterior material for an electricity storage device has a maximum reflected light intensity A of 50 or less in a light receiving angle range of 0.0° or more and 90.0° or less, measured for at least one surface of the metal foil layer at every 0.1° of light receiving angle using a goniophotometer under a condition of an incident light angle of 60°.

In the first aspect of the present disclosure, the exterior material for an electricity storage device may not include a base material layer. That is, the first aspect of the present disclosure may be an exterior material for an electricity storage device that is composed of a laminate including, in order from the outside, at least a metal foil layer and a heat-sealable resin layer, and that has a maximum reflected light intensity A of 50 or less in the light receiving angle range of 0.0° to 90.0°, measured for every 0.1° of light receiving angle at an incident light angle of 60° using a goniophotometer, for at least one surface of the metal foil layer.

A second aspect of the present disclosure provides the invention having the following aspects.
The laminate includes, in order from the outside, at least a base layer, a metal foil layer, and a heat-sealable resin layer.
The exterior material for an electricity storage device has a maximum reflected light intensity B of 300 or more in a light receiving angle range of 45.0° or more and 75.0° or less, measured for at least one surface of the metal foil layer at every 0.1° of light receiving angle using a variable angle photometer under a condition of an incident light angle of 60°.

In a second aspect of the present disclosure, the exterior material for an electricity storage device may not include a base material layer. That is, the second aspect of the present disclosure may be an exterior material for an electricity storage device that is composed of a laminate including, in order from the outside, at least a metal foil layer and a heat-sealable resin layer, and that has a maximum reflected light intensity B of 300 or more for at least one surface of the metal foil layer in a light receiving angle range of 45.0° to 75.0°, measured at every 0.1° of light receiving angle under a condition of an incident light angle of 60° using a goniophotometer.

According to the present disclosure, it is possible to provide an exterior material for an electricity storage device that is composed of a laminate having, in order from the outside, at least a base layer, a metal foil layer, and a heat-sealable resin layer, and has excellent formability.According to the present disclosure, it is possible to provide an exterior material for an electricity storage device that is composed of a laminate having, in order from the outside, at least a metal foil layer, and a heat-sealable resin layer, and has excellent formability.In addition, according to the present disclosure, it is possible to provide a manufacturing method for these exterior materials for electricity storage devices, and an electricity storage device that uses these exterior materials for electricity storage devices.

1 is a schematic diagram showing an example of a cross-sectional structure of an exterior material for an electricity storage device according to the present disclosure. 1 is a schematic diagram showing an example of a cross-sectional structure of an exterior material for an electricity storage device according to the present disclosure. 1 is a schematic diagram showing an example of a cross-sectional structure of an exterior material for an electricity storage device according to the present disclosure. 1 is a schematic diagram showing an example of a cross-sectional structure of an exterior material for an electricity storage device according to the present disclosure. FIG. 2 is a schematic diagram for illustrating a method for housing an electricity storage device element in a package formed from the exterior material for an electricity storage device of the present disclosure. FIG. 13 is a schematic diagram of a graph showing the relationship between the reflected light intensity of the matte surface and the light receiving angle measured using a goniophotometer for the surface of the metal foil layer in Example 2. FIG. 13 is a schematic diagram of a graph showing the relationship between the reflected light intensity of the glossy surface and the light receiving angle measured using a goniophotometer for the surface of the metal foil layer in Example 2.

The exterior material for an electricity storage device according to the first aspect of the present disclosure is composed of a laminate including, in order from the outside, at least a base layer, a metal foil layer, and a heat-sealable resin layer, and the maximum reflected light intensity A of at least one surface of the metal foil layer is 50 or less in the light receiving angle range of 0.0° to 90.0°, measured at every 0.1° of light receiving angle under the condition of an incident light angle of 60° using a goniophotometer. As described above, in the first aspect of the present disclosure, the exterior material for an electricity storage device may not include a base layer.

Furthermore, the exterior material for an electricity storage device according to the second aspect of the present disclosure is composed of a laminate including, in order from the outside, at least a base layer, a metal foil layer, and a heat-sealable resin layer, and the maximum reflected light intensity B of at least one surface of the metal foil layer is 300 or more in a light receiving angle range of 45.0° to 75.0°, measured at every 0.1° of light receiving angle under a condition of an incident light angle of 60° using a goniophotometer. As described above, in the second aspect of the present disclosure, the exterior material for an electricity storage device may not include a base layer.

The exterior material for a power storage device of the present disclosure will be described in detail below. In the following description, matters specific to the first or second embodiment will be clearly indicated as to which embodiment they relate to, and matters common to the first and second embodiments will be described without any particular indication as to the present disclosure. In addition, in this specification, a numerical range indicated by "~" means "not less than" or "not more than". For example, the expression "2 to 15 mm" means 2 mm or more and 15 mm or less. In the numerical ranges described in stages in this disclosure, the upper limit or lower limit described in a certain numerical range may be replaced with the upper limit or lower limit of another numerical range described in stages. In addition, the upper limit and upper limit, the upper limit and lower limit, or the lower limit and lower limit described separately may be combined to form a numerical range. In addition, in the numerical ranges described in this disclosure, the upper limit or lower limit described in a certain numerical range may be replaced with a value shown in the examples.

In the case of the exterior material for the electric storage device, the MD (machine direction) and TD (transverse direction) of the metal foil layer 3 described later can usually be determined in the manufacturing process. For example, when the metal foil layer 3 is made of a metal foil such as an aluminum alloy foil or a stainless steel foil, linear lines called rolling marks are formed on the surface of the metal foil in the rolling direction (RD) of the metal foil. Since the rolling marks extend along the rolling direction, the rolling direction of the metal foil can be determined by observing the surface of the metal foil. In the manufacturing process of the laminate, the MD of the laminate usually coincides with the RD of the metal foil, so the MD of the laminate can be identified by observing the surface of the metal foil of the laminate and identifying the rolling direction (RD) of the metal foil. In addition, since the TD of the laminate is perpendicular to the MD of the laminate, the TD of the laminate can also be identified.

In addition, when the MD of the electrical storage device exterior material cannot be identified due to rolling marks on the metal foil such as aluminum alloy foil or stainless steel foil, it can be identified by the following method. One method for confirming the MD of an electrical storage device exterior material is to observe the cross section of the heat-sealable resin layer of the electrical storage device exterior material with an electron microscope to confirm the sea-island structure. In this method, the direction parallel to the cross section in which the average diameter of the shape of the islands in the direction perpendicular to the thickness direction of the heat-sealable resin layer was maximum can be determined as the MD. Specifically, the cross section in the length direction of the heat-sealable resin layer and each cross section (10 cross sections in total) that is angled 10 degrees from the direction parallel to the cross section in the length direction to the direction perpendicular to the cross section in the length direction are observed with an electron microscope to confirm the sea-island structure. Next, the shape of each individual island is observed in each cross section. For each island shape, the straight line distance connecting the leftmost end in the direction perpendicular to the thickness direction of the heat-sealable resin layer and the rightmost end in the vertical direction is taken as the diameter y. For each cross section, the average of the top 20 diameters y of the island shapes is calculated in descending order of diameter y. The direction parallel to the cross section with the largest average diameter y of the island shapes is determined to be the MD.

1. Laminated structure of the exterior material for a power storage device The exterior material for a power storage device 10 of the present disclosure is composed of a laminate including, in this order from the outside, a base material layer 1, a metal foil layer 3, and a heat-sealable resin layer 4, as shown in FIG. 1, for example. In the exterior material for a power storage device 10, the base material layer 1 is the outermost layer, and the heat-sealable resin layer 4 is the innermost layer. When assembling an electricity storage device using the exterior material for a power storage device 10 and an electricity storage device element, the heat-sealable resin layers 4 of the exterior material for a power storage device 10 are opposed to each other, and the electricity storage device element is accommodated in a space formed by heat-sealing the periphery. In the laminate constituting the exterior material for a power storage device 10 of the present disclosure, the metal foil layer 3 is used as a reference, and the heat-sealable resin layer 4 side is the inner side of the metal foil layer 3, and the base material layer 1 side is the outer side of the metal foil layer 3. The exterior packaging material 10 for an electricity storage device according to the present disclosure may be composed of a laminate including, in this order, a metal foil layer 3 and a heat-sealable resin layer 4. In this case, the side of the metal foil layer 3 opposite to the heat-sealable resin layer 4 becomes the outermost layer, and the heat-sealable resin layer 4 becomes the innermost layer.

As shown in Figures 2 to 4, for example, the exterior material 10 for an electricity storage device may have an adhesive layer 2 between the base material layer 1 and the metal foil layer 3, if necessary, for the purpose of increasing the adhesion between these layers. Also, as shown in Figures 3 and 4, for example, the exterior material 10 for an electricity storage device may have an adhesive layer 5 between the metal foil layer 3 and the heat-sealable resin layer 4, if necessary, for the purpose of increasing the adhesion between these layers. Also, as shown in Figure 4, a surface coating layer 6 or the like may be provided on the outside of the base material layer 1 (the side opposite to the heat-sealable resin layer 4) if necessary.

The thickness of the laminate constituting the exterior material 10 for an electricity storage device is not particularly limited, but from the viewpoint of cost reduction, energy density improvement, etc., examples of the thickness include about 300 μm or less, preferably about 250 μm or less, about 210 μm or less, about 190 μm or less, about 180 μm or less, about 155 μm or less, and about 120 μm or less. In addition, from the viewpoint of maintaining the function of the exterior material for an electricity storage device, which is to protect the electricity storage device elements, the thickness of the laminate constituting the electricity storage device exterior material 10 is preferably about 35 μm or more, about 45 μm or more, about 60 μm or more, about 155 μm or more, and about 190 μm or more. In addition, preferred ranges of the laminate constituting the exterior material 10 for an electrical storage device are, for example, about 35 to 300 μm, about 35 to 250 μm, about 35 to 210 μm, about 35 to 190 μm, about 35 to 180 μm, about 35 to 155 μm, about 35 to 120 μm, about 45 to 300 μm, about 45 to 250 μm, about 45 to 210 μm, about 45 to 190 μm, about 45 to 180 μm, about 45 to 155 μm, about 45 to 120 μm, about 60 to 300 μm, about 60 to 250 μm, about 60 to Examples include about 210 μm, about 60 to 190 μm, about 60 to 180 μm, about 60 to 155 μm, about 60 to 120 μm, about 155 to 300 μm, about 155 to 250 μm, about 155 to 210 μm, about 155 to 190 μm, about 155 to 180 μm, about 190 to 300 μm, about 190 to 250 μm, and about 190 to 210 μm. In particular, about 60 to 155 μm is preferred when making the power storage device lighter and thinner, and about 155 to 190 μm is preferred when improving formability.

In the exterior material 10 for a storage battery device, the ratio of the total thickness of the base material layer 1, the adhesive layer 2 provided as needed, the metal foil layer 3, the adhesive layer 5 provided as needed, the heat-sealable resin layer 4, and the surface coating layer 6 provided as needed to the thickness (total thickness) of the laminate constituting the exterior material 10 for a storage battery device is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. As a specific example, when the exterior material 10 for a storage battery device of the present disclosure includes the base material layer 1, the adhesive layer 2, the metal foil layer 3, the adhesive layer 5, and the heat-sealable resin layer 4, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the exterior material 10 for a storage battery device is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. Also, even when the exterior material 10 for an electric storage device of the present disclosure is a laminate including a base layer 1, an adhesive layer 2, a metal foil layer 3, and a heat-sealable resin layer 4, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the exterior material 10 for an electric storage device can be, for example, 80% or more, preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more.

2. Layers forming the exterior material for an electricity storage device [Base material layer 1]
In the present disclosure, the substrate layer 1 is a layer provided for the purpose of exhibiting the function as a substrate of the exterior material for an electricity storage device, etc. The substrate layer 1 is located on the outer layer side of the exterior material for an electricity storage device.

The material from which the base layer 1 is made is not particularly limited, as long as it has the function of a base material, i.e., at least insulating properties. The base layer 1 can be made, for example, using a resin, which may contain additives as described below.

When the substrate layer 1 is made of a resin, the substrate layer 1 can be made of, for example, a resin film. When the substrate layer 1 is made of a resin film, a preformed resin film may be used as the substrate layer 1 when the substrate layer 1 is laminated with the metal foil layer 3 or the like to manufacture the exterior material for a storage device 10 of the present disclosure. In addition, the resin forming the substrate layer 1 may be formed into a film on the surface of the metal foil layer 3 or the like by extrusion molding or coating to form the substrate layer 1 formed of a resin film. The resin film may be an unstretched film or a stretched film. Examples of stretched films include uniaxially stretched films and biaxially stretched films, and biaxially stretched films are preferred. Examples of stretching methods for forming a biaxially stretched film include sequential biaxial stretching, inflation, and simultaneous biaxial stretching. Examples of methods for applying a resin include roll coating, gravure coating, and extrusion coating.

The resin forming the base layer 1 may be, for example, polyester, polyamide, polyolefin, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, phenolic resin, or modified versions of these resins. The resin forming the base layer 1 may also be a copolymer of these resins or a modified version of the copolymer. It may also be a mixture of these resins.

The base layer 1 preferably contains these resins as the main component, and more preferably contains polyester or polyamide as the main component. Here, the main component means that the content of the resin components contained in the base layer 1 is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more. For example, when the base layer 1 contains polyester or polyamide as the main component, it means that the content of polyester or polyamide among the resin components contained in the base layer 1 is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more.

Among these, polyester and polyamide are preferred as resins for forming the base layer 1.

Specific examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymer polyesters. Examples of copolymer polyesters include copolymer polyesters in which ethylene terephthalate is the main repeating unit. Specific examples include copolymer polyesters in which ethylene terephthalate is the main repeating unit and is polymerized with ethylene isophthalate (hereinafter abbreviated as polyethylene (terephthalate/isophthalate)), polyethylene (terephthalate/adipate), polyethylene (terephthalate/sodium sulfoisophthalate), polyethylene (terephthalate/sodium isophthalate), polyethylene (terephthalate/phenyl-dicarboxylate), and polyethylene (terephthalate/decanedicarboxylate). These polyesters may be used alone or in combination of two or more.

Specific examples of polyamides include aliphatic polyamides such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, and copolymers of nylon 6 and nylon 66; hexamethylenediamine-isophthalic acid-terephthalic acid copolymer polyamides such as nylon 6I, nylon 6T, nylon 6IT, and nylon 6I6T (I represents isophthalic acid, T represents terephthalic acid) which contain structural units derived from terephthalic acid and/or isophthalic acid, and aromatic polyamides such as polyamide MXD6 (polymetaxylylene adipamide); alicyclic polyamides such as polyamide PACM6 (polybis(4-aminocyclohexyl)methane adipamide); polyamides copolymerized with lactam components or isocyanate components such as 4,4'-diphenylmethane diisocyanate; polyesteramide copolymers and polyetheresteramide copolymers which are copolymers of copolymerized polyamides with polyesters or polyalkylene ether glycols; and polyamides such as copolymers of these copolymers. These polyamides may be used alone or in combination of two or more.

The substrate layer 1 preferably includes at least one of a polyester film, a polyamide film, and a polyolefin film, preferably includes at least one of a stretched polyester film, a stretched polyamide film, and a stretched polyolefin film, more preferably includes at least one of a stretched polyethylene terephthalate film, a stretched polybutylene terephthalate film, a stretched nylon film, and a stretched polypropylene film, and even more preferably includes at least one of a biaxially oriented polyethylene terephthalate film, a biaxially oriented polybutylene terephthalate film, a biaxially oriented nylon film, and a biaxially oriented polypropylene film.

The base layer 1 may be a single layer, or may be composed of two or more layers. When the base layer 1 is composed of two or more layers, the base layer 1 may be a laminate in which resin films are laminated with an adhesive or the like, or a laminate of resin films in which resins are co-extruded to form two or more layers. Furthermore, a laminate of resin films in which resins are co-extruded to form two or more layers may be used as the base layer 1 without being stretched, or may be uniaxially or biaxially stretched to form the base layer 1.

Specific examples of laminates of two or more resin films in the base layer 1 include a laminate of a polyester film and a nylon film, a laminate of two or more nylon films, and a laminate of two or more polyester films, and preferably a laminate of a stretched nylon film and a stretched polyester film, a laminate of two or more stretched nylon films, and a laminate of two or more stretched polyester films. For example, when the base layer 1 is a laminate of two resin films, a laminate of a polyester resin film and a polyester resin film, a laminate of a polyamide resin film and a polyamide resin film, or a laminate of a polyester resin film and a polyamide resin film is preferred, and a laminate of a polyethylene terephthalate film and a polyethylene terephthalate film, a laminate of a nylon film and a nylon film, or a laminate of a polyethylene terephthalate film and a nylon film is more preferred. In addition, when the base layer 1 is a laminate of two or more resin films, it is preferred that the polyester resin film is located in the outermost layer of the base layer 1, because the polyester resin is less likely to discolor when, for example, an electrolyte is attached to the surface. In the laminate of the polyester resin film and the polyamide resin film, preferred ranges of the thickness of the polyester resin film are about 2 to 33 μm, about 2 to 28 μm, about 2 to 23 μm, about 2 to 18 μm, about 2 to 11 μm, about 2 to 8 μm, about 10 to 33 μm, about 10 to 28 μm, about 10 to 23 μm, about 10 to 18 μm, about 18 to 33 μm, and about 18 to 28 μm. degree, about 18 to 23 μm, and preferred ranges for the thickness of the polyamide resin film include about 2 to 33 μm, about 2 to 28 μm, about 2 to 23 μm, about 2 to 18 μm, about 2 to 11 μm, about 2 to 8 μm, about 10 to 33 μm, about 10 to 28 μm, about 10 to 23 μm, about 10 to 18 μm, about 18 to 33 μm, about 18 to 28 μm, and about 18 to 23 μm.

When the base layer 1 is a laminate of two or more resin films, the two or more resin films may be laminated via an adhesive. Preferred adhesives include those similar to those exemplified in the adhesive layer 2 described below. The method for laminating two or more resin films is not particularly limited, and known methods can be used, such as dry lamination, sandwich lamination, extrusion lamination, and thermal lamination, and preferably dry lamination. When laminating by the dry lamination method, it is preferable to use a polyurethane adhesive as the adhesive. In this case, the thickness of the adhesive is, for example, about 2 to 5 μm. Alternatively, an anchor coat layer may be formed on the resin film and laminated. The anchor coat layer may be the same as the adhesive exemplified in the adhesive layer 2 described below. In this case, the thickness of the anchor coat layer is, for example, about 0.01 to 1.0 μm.

Additives such as lubricants, flame retardants, antiblocking agents, antioxidants, light stabilizers, tackifiers, antistatic agents, and colorants may be present on at least one of the surface and interior of the base layer 1. Only one type of additive may be used, or two or more types may be mixed together.

In the present disclosure, from the viewpoint of improving the formability of the exterior material for a storage battery device, it is preferable that a lubricant is present on at least one of the surface and the inside of the base material layer 1. The lubricant is not particularly limited, but preferably includes amide-based lubricants. Specific examples of amide-based lubricants include, for example, saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides. Specific examples of saturated fatty acid amides include lauric acid amides, palmitic acid amides, stearic acid amides, behenic acid amides, and hydroxystearic acid amides. Specific examples of unsaturated fatty acid amides include oleic acid amides and erucic acid amides. Specific examples of substituted amides include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, and N-stearyl erucic acid amide. Specific examples of methylol amides include methylol stearic acid amide. Specific examples of saturated fatty acid bisamides include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbehenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N,N'-distearyl adipic acid amide, N,N'-distearyl sebacic acid amide, etc. Specific examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyl adipic acid amide, N,N'-dioleyl sebacic acid amide, etc. Specific examples of fatty acid ester amides include stearamide ethyl stearate, etc. Specific examples of aromatic bisamides include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, and N,N'-distearylisophthalic acid amide. The lubricant may be used alone or in combination of two or more types, preferably in combination of two or more types.

When a lubricant is present on the surface of the base layer 1, the amount of the lubricant present is not particularly limited, but may be, for example, about 3 mg/m ² or more, preferably about 4 mg/m ² or more, or about 5 mg/m ² or more. The amount of the lubricant present on the surface of the base layer 1 may be, for example, about 15 mg/m ² or less, preferably about 14 mg/m ² or less, or about 10 mg/m ² or less. The preferred range of the amount of the lubricant present on the surface of the base layer 1 is about 3 to 15 mg/m ² , about 3 to 14 mg/m ² , about 3 to 10 mg/m ² , about 4 to 15 mg/m ² , about 4 to 14 mg/m ² , about 4 to 10 mg/m ² , about 5 to 15 mg/m ² , about 5 to 14 mg/m ² , or about 5 to 10 mg/m ² .

The lubricant present on the surface of the base layer 1 may be a lubricant exuded from the resin that constitutes the base layer 1, or a lubricant applied to the surface of the base layer 1.

The thickness of the substrate layer 1 is not particularly limited as long as it functions as a substrate, but may be, for example, about 3 μm or more, and preferably about 10 μm or more. The thickness of the substrate layer 1 may be, for example, about 100 μm or less, about 90 μm or less, about 70 μm or less, or about 50 μm or less, preferably about 35 μm or less, 11 μm or less, or 8 μm or less. In addition, preferred ranges of the thickness of the base layer 1 include about 3 to 100 μm, about 3 to 90 μm, about 3 to 70 μm, about 3 to 50 μm, about 3 to 35 μm, about 3 to 11 μm, about 3 to 8 μm, about 10 to 100 μm, about 10 to 90 μm, about 10 to 70 μm, about 10 to 50 μm, about 10 to 35 μm, and about 10 to 11 μm. In particular, when making the electric storage device lighter and thinner, about 3 to 35 μm, about 3 to 11 μm, and about 3 to 8 μm are preferred, and when improving moldability, about 35 to 50 μm is preferred. When the base layer 1 is a laminate of two or more layers of resin films, the thickness of the resin films constituting each layer is not particularly limited, but may be, for example, about 2 μm or more, preferably about 10 μm or more, and about 18 μm or more. The thickness of the resin film constituting each layer is, for example, about 33 μm or less, preferably about 28 μm or less, about 23 μm or less, about 18 μm or less, 11 μm or less, or 8 μm or less. The preferred range of the thickness of the resin film constituting each layer is about 2 to 33 μm, about 2 to 28 μm, about 2 to 23 μm, about 2 to 18 μm, about 2 to 11 μm, about 2 to 8 μm, about 10 to 33 μm, about 10 to 28 μm, about 10 to 23 μm, about 10 to 18 μm, about 18 to 33 μm, about 18 to 28 μm, or about 18 to 23 μm.

The base layer 1 contains a colorant, so that the exterior material for the electricity storage device can be colored. Known colorants such as pigments and dyes can be used as the colorant. Furthermore, only one type of colorant may be used, or two or more types may be mixed together.

The type of pigment is not particularly limited as long as it does not impair the function of the substrate layer 1 as a substrate. Examples of organic pigments include azo-based, phthalocyanine-based, quinacridone-based, anthraquinone-based, dioxazine-based, indigothioindigo-based, perinone-perylene-based, isoindolenine-based, and benzimidazolone-based pigments, while examples of inorganic pigments include carbon black-based, titanium oxide-based, cadmium-based, lead-based, chromium oxide-based, and iron-based pigments, as well as finely powdered mica and fish scale foil.

Among colorants, carbon black is preferred in order to give the exterior material for an electricity storage device a black appearance. Also, from the perspective of dissipating heat generated by the electricity storage device, it is preferable to use mica.

The average particle size of the pigment is not particularly limited, and may be, for example, about 0.03 to 5 μm, and preferably about 0.05 to 2 μm. The average particle size of the pigment is the median size measured with a laser diffraction/scattering type particle size distribution measuring device.

The content of the colorant or pigment in the base layer 1 is not particularly limited as long as the exterior material for the electricity storage device is colored, and may be, for example, about 5 to 60% by mass, and preferably about 10 to 40% by mass.

[Adhesive layer 2]
In the exterior material for an electricity storage device of the present disclosure, the adhesive layer 2 is a layer that is provided between the base material layer 1 and the metal foil layer 3 as necessary for the purpose of increasing the adhesion between them.

The adhesive layer 2 is formed from an adhesive capable of bonding the base material layer 1 and the metal foil layer 3. There are no limitations on the adhesive used to form the adhesive layer 2, and it may be any of a chemical reaction type, a solvent volatilization type, a hot melt type, a hot pressure type, etc. It may also be a two-component curing adhesive (two-component adhesive), a one-component curing adhesive (one-component adhesive), or a resin that does not involve a curing reaction. The adhesive layer 2 may be a single layer or multiple layers.

Specific examples of adhesive components contained in the adhesive include polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymer polyesters; polyethers; polyurethanes; epoxy resins; phenolic resins; polyamides such as nylon 6, nylon 66, nylon 12, and copolymer polyamides; polyolefin resins such as polyolefins, cyclic polyolefins, acid-modified polyolefins, and acid-modified cyclic polyolefins; polyvinyl acetate; cellulose; (meth)acrylic resins; polyimides; polycarbonates; amino resins such as urea resins and melamine resins; rubbers such as chloroprene rubber, nitrile rubber, and styrene-butadiene rubber; and silicone resins. These adhesive components may be used alone or in combination of two or more. Of these adhesive components, polyurethane adhesives are preferred. Furthermore, the adhesive strength of these adhesive component resins can be increased by using an appropriate curing agent in combination. The curing agent is selected from polyisocyanates, polyfunctional epoxy resins, oxazoline group-containing polymers, polyamine resins, acid anhydrides, etc., depending on the functional groups of the adhesive components.

The polyurethane adhesive may be, for example, a polyurethane adhesive containing a first agent containing a polyol compound and a second agent containing an isocyanate compound. A two-part curing polyurethane adhesive may preferably be used, in which a polyol such as polyester polyol, polyether polyol, or acrylic polyol is used as the first agent, and an aromatic or aliphatic polyisocyanate is used as the second agent. In addition, the polyurethane adhesive may be, for example, a polyurethane adhesive containing a polyurethane compound in which a polyol compound has been reacted with an isocyanate compound in advance, and an isocyanate compound. In addition, the polyurethane adhesive may be, for example, a polyurethane adhesive containing a polyurethane compound in which a polyol compound has been reacted with an isocyanate compound in advance, and a polyol compound. In addition, the polyurethane adhesive may be, for example, a polyurethane adhesive in which a polyurethane compound in which a polyol compound has been reacted with an isocyanate compound in advance is cured by reacting it with moisture in the air or the like. As the polyol compound, it is preferable to use a polyester polyol having a hydroxyl group on the side chain in addition to the hydroxyl group at the end of the repeating unit. The second agent may be an aliphatic, alicyclic, aromatic, or araliphatic isocyanate compound. Examples of the isocyanate compound include hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), hydrogenated XDI (H6XDI), hydrogenated MDI (H12MDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and naphthalene diisocyanate (NDI). Examples of the polyisocyanate compound include polyfunctional isocyanate modified compounds of one or more of these diisocyanates. In addition, a polymer (e.g., a trimer) may be used as the polyisocyanate compound. Examples of such polymers include adducts, biurets, and nurates. The adhesive layer 2 is formed from a polyurethane adhesive, which gives the exterior material for the electricity storage device excellent electrolyte resistance, and prevents the base layer 1 from peeling off even if electrolyte adheres to the side surface.

Furthermore, the adhesive layer 2 is permitted to contain other components as long as they do not impair adhesion, and may contain colorants, thermoplastic elastomers, tackifiers, fillers, etc. By including a colorant in the adhesive layer 2, the exterior material for the electricity storage device can be colored. As the colorant, known colorants such as pigments and dyes can be used. Furthermore, only one type of colorant may be used, or two or more types may be mixed together.

There are no particular limitations on the type of pigment, so long as it does not impair the adhesiveness of the adhesive layer 2. Examples of organic pigments include azo-based, phthalocyanine-based, quinacridone-based, anthraquinone-based, dioxazine-based, indigothioindigo-based, perinone-perylene-based, isoindolenine-based, and benzimidazolone-based pigments, while examples of inorganic pigments include carbon black-based, titanium oxide-based, cadmium-based, lead-based, chromium oxide-based, and iron-based pigments, as well as finely powdered mica and fish scale foil.

Among colorants, carbon black is preferred, for example to give the exterior material for an electricity storage device a black appearance.

The average particle size of the pigment is not particularly limited, and may be, for example, about 0.03 to 5 μm, about 0.05 to 5 μm, about 0.08 to 5 μm, and preferably about 0.03 to 2 μm, about 0.05 to 2 μm, or about 0.08 to 2 μm. The average particle size of the pigment is the median size measured using a laser diffraction/scattering type particle size distribution measuring device.

The content of the colorant or pigment in the adhesive layer 2 is not particularly limited as long as the exterior material for the electricity storage device is colored, and may be, for example, about 5 to 60% by mass, and preferably 10 to 40% by mass.

The thickness of the adhesive layer 2 is not particularly limited as long as it can bond the base layer 1 and the metal foil layer 3, but is, for example, about 1 μm or more, about 2 μm or more. The thickness of the adhesive layer 2 is, for example, about 10 μm or less, about 5 μm or less. Preferred ranges for the thickness of the adhesive layer 2 include about 1 to 10 μm, about 1 to 5 μm, about 2 to 10 μm, and about 2 to 5 μm.

[Colored layer]
The colored layer is a layer (not shown) that is provided between the base material layer 1 and the metal foil layer 3 as necessary. When the adhesive layer 2 is provided, a colored layer may be provided between the base material layer 1 and the adhesive layer 2, or between the adhesive layer 2 and the metal foil layer 3. A colored layer may also be provided on the outside of the base material layer 1. By providing a colored layer, the exterior material for an electricity storage device can be colored.

The colored layer can be formed, for example, by applying an ink containing a colorant to the surface of the base layer 1 or the surface of the metal foil layer 3. As the colorant, known pigments, dyes, etc. can be used. Furthermore, only one type of colorant may be used, or two or more types may be mixed together.

Specific examples of colorants contained in the colored layer include those exemplified in the [Adhesive layer 2] section.

[Metal foil layer 3]
In the packaging material for an electricity storage device, the metal foil layer 3 is a layer that at least prevents the intrusion of moisture (a barrier layer).

The metal foil layer 3 is a layer made of a metal material. Specific examples of the metal material that makes up the metal foil layer 3 include aluminum alloys, stainless steel, titanium steel, and steel plates, and it is preferable that the metal foil layer 3 contains at least one of an aluminum alloy foil and a stainless steel foil. The metal foil layer 3 may be provided in multiple layers.

In the metal foil layer 3, the layer made of the above-mentioned metal material may contain recycled metal material. Examples of recycled metal material include recycled aluminum alloy, stainless steel, titanium steel, or steel plate. These recycled materials can be obtained by known methods. Recycled aluminum alloy can be obtained by the manufacturing method described in WO 2022/092231. The metal foil layer 3 may be made of only recycled material, or may be made of a mixture of recycled and virgin materials. Note that recycled metal material refers to metal material that has been made reusable by collecting, isolating, and refining various products used in the city and waste from manufacturing processes. Also, virgin metal material refers to new metal material that has been refined from natural metal resources (raw materials) and is not recycled material.

In the first aspect of the present disclosure, the maximum reflected light intensity A at at least one surface of the metal foil layer is 50 or less in the range of 0.0° to 90.0° of light receiving angles, measured at every 0.1° of light receiving angle using a goniophotometer under the condition of an incident light angle of 60°. The surface of the metal foil layer inevitably has a fine uneven shape, but if the value of the maximum reflected light intensity A is greater than 50, it can be said that the surface of the metal foil layer is excessively flat from the viewpoint of formability of the exterior material for a storage battery device. If the surface is excessively smooth, the anchor effect due to the uneven shape is small, and the adhesive strength at the interface with the layer in contact with the metal foil layer (e.g., substrate layer, adhesive layer, adhesive layer, heat-sealable resin layer, etc.) is not increased, and the formability as an exterior material for a storage battery device tends to decrease. In the present disclosure, the maximum reflected light intensity A on at least one surface of the metal foil layer is 50 or less, so that the surface of the metal foil layer has a moderately uneven shape, which suppresses peeling between the metal foil layer and the adjacent layer during molding of the exterior material for an electrical storage device, and is considered to exhibit excellent moldability. The method for measuring the maximum reflected light intensity A is described below.

In the second aspect of the present disclosure described below, the maximum reflected light intensity A is preferably 50 or less for at least one surface of the metal foil layer (preferably the matte surface of the metal foil layer) in the light receiving angle range of 0.0° to 90.0°, measured at every 0.1° of light receiving angle using a goniophotometer under the condition of an incident light angle of 60°.

In the present disclosure, for example, one side of the metal foil layer 3 is a glossy surface (a mirror surface with metallic luster) and the other side is a matte surface (a matte pear-finished surface). In the exterior material for an energy storage device of the present disclosure, the base material layer 1 side of the metal foil layer 3 may be a matte surface, or the heat-sealable resin layer 4 side of the metal foil layer 3 may be a matte surface, but from the viewpoint of making it easy to identify product information, etc. printed on the surface of the base material layer, it is preferable that the base material layer 1 side of the metal foil layer 3 is a matte surface.

In the present disclosure, the surfaces of the metal foil layer 3 are compared, and the surface with a relatively lower gloss is the matte surface, and the surface with a relatively higher gloss is the glossy surface. More specifically, the maximum reflected light intensity on both sides of the metal foil layer is measured, and the surface with the higher maximum reflected light intensity is the glossy surface of the metal foil layer, and the surface with the lower maximum reflected light intensity is the matte surface of the metal foil layer. Also, for example, during the manufacture of aluminum alloy foil, the surface that is in contact with the rolling rolls when the aluminum alloy foil is rolled is the glossy surface, and the surface where the two aluminum alloy foils meet when rolling two sheets of aluminum alloy foil together is the matte surface.

In order to more effectively exert the effects of the present disclosure, in both the first and second aspects, it is preferable that the matte surface of the metal foil layer 3 has a maximum reflected light intensity A of 50 or less.

From the viewpoint of more suitably exerting the effect of the first aspect of the present disclosure, the maximum reflected light intensity A on at least one surface of the metal foil layer is preferably 50 or less, more preferably 40 or less, and even more preferably 30 or less. The maximum reflected light intensity A is preferably 10 or more, more preferably 16 or more, and even more preferably 20 or more. Preferred ranges of the maximum reflected light intensity A include about 10 to 50, about 10 to 40, about 10 to 30, about 16 to 50, about 16 to 40, about 16 to 30, about 20 to 50, about 20 to 40, and about 20 to 30. From the viewpoint of more suitably exerting the effect of the present disclosure, it is more preferable that the matte surface of the metal foil layer 3 has these values of maximum reflected light intensity A. In the second aspect of the present disclosure described later, it is also more preferable that the surface of at least one surface of the metal foil layer (preferably the matte surface of the metal foil layer) has these values of maximum reflected light intensity A.

In order to adjust the maximum reflected light intensity A to 50 or less, it is effective to adjust the amount of rolling oil used when manufacturing the metal foil layer so that the surface has an appropriate uneven shape, or to adjust the conveying tension during rolling. It is preferable to confirm that the maximum reflected light intensity A of at least one surface of the obtained metal foil layer is 50 or less, and to use it as the metal foil layer of the exterior material for the electricity storage device disclosed herein.

Furthermore, from the viewpoint of more optimally exerting the effects of the first aspect of the present disclosure, the maximum slope C for at least one surface of the metal foil layer, measured at every 0.1° of light receiving angle using a goniophotometer under a condition of an incident light angle of 60°, within the range of light receiving angles of 0.0° to 90.0° is preferably 10.0 or less, more preferably 8.0 or less, and even more preferably 5.0 or less, and the maximum slope C is preferably 0.5 or more, more preferably 1.0 or more, and even more preferably 2.0 or more. Preferred ranges for the maximum slope C include approximately 0.5 to 10.0, approximately 0.5 to 8.0, approximately 0.5 to 5.0, approximately 1.0 to 10.0, approximately 1.0 to 8.0, approximately 1.0 to 5.0, approximately 2.0 to 10.0, approximately 2.0 to 8.0, and approximately 2.0 to 5.0. From the viewpoint of more suitably exerting the effects of the first aspect of the present disclosure, it is more preferable that the matte surface of the metal foil layer 3 has these maximum slope C values. Also, in the second aspect of the present disclosure described below, it is more preferable that at least one surface of the metal foil layer (preferably the matte surface of the metal foil layer 3) has these maximum slope C values.

When the value of the maximum slope C is greater than 10.0, the surface of the metal foil layer can be said to be flat. As described above, if the surface of the metal foil layer is excessively smooth, the layer in contact with the surface (e.g., a base layer, an adhesive layer, an adhesive layer, a heat-sealable resin layer, etc.) has a small anchor effect due to the uneven shape, and the adhesive strength between the layers is not increased, resulting in poor formability as an exterior material for a storage device. In the present disclosure, when the maximum slope C on at least one surface of the metal foil layer is 10.0 or less, the surface of the metal foil layer has a more suitable uneven shape, and peeling between the metal foil layer and the adjacent layer during molding of the exterior material for a storage device is suppressed, and it can be considered that excellent formability is exhibited. In order to adjust the value of the maximum slope C to 10.0 or less, it is effective to adjust the amount of rolling oil when manufacturing the metal foil layer, adjust the conveying tension during rolling, etc., so that the surface has a moderate uneven shape. The method for measuring the maximum slope C is as described below.

In addition, in a second aspect of the present disclosure, the maximum reflected light intensity B for at least one surface of the metal foil layer is 300 or more in the range of light receiving angles of 45.0° or more and 75.0° or less, measured at every 0.1° of light receiving angle at an incident light angle of 60° using a goniophotometer. The surface of the metal foil layer inevitably has a fine uneven shape, and the smaller the value of the maximum reflected light intensity B is below 300, the sharper the convex or concave portion of the fine uneven shape that the metal foil layer inevitably has. The sharper the convex or concave portion of the uneven shape on the surface of the metal foil layer, the more likely it is that cracks will occur in the metal foil layer, starting from the sharp convex or concave portion, when the metal foil layer is stretched during molding of the exterior material for an electricity storage device. In the second aspect of the present disclosure, the maximum reflected light intensity B on at least one surface of the metal foil layer is 300 or more, and the finely uneven convex or concave portions are flattened, which is believed to favorably suppress cracking of the metal foil layer during molding of the exterior material for an electrical storage device, thereby providing excellent moldability.

In the first aspect of the present disclosure described above, the maximum reflected light intensity B of the other surface of the metal foil layer (preferably the glossy surface of the metal foil layer) is preferably 300 or more in the light receiving angle range of 45.0° to 75.0°, measured at every 0.1° of light receiving angle using a goniophotometer under the condition of an incident light angle of 60°.

In addition, from the viewpoint of more optimally exerting the effects of the present disclosure, in both the first and second aspects, it is preferable that the maximum reflected light intensity B of the glossy surface of the metal foil layer 3 has a value of 300 or more.

From the viewpoint of more suitably exerting the effects of the second aspect of the present disclosure, the maximum reflected light intensity B on at least one surface of the metal foil layer is preferably 300 or more, more preferably 400 or more, and even more preferably 500 or more, and the maximum reflected light intensity B is preferably 650 or less, more preferably 580 or less, and even more preferably 510 or less, and preferred ranges of the maximum reflected light intensity B include about 300 to 650, about 300 to 580, about 300 to 510, about 400 to 650, about 400 to 580, about 400 to 510, about 500 to 650, about 500 to 580, and about 500 to 510. From the viewpoint of more suitably exerting the effects of the present disclosure, it is more preferable that the glossy surface of the metal foil layer 3 has these values of maximum reflected light intensity B. In the first aspect of the present disclosure, it is more preferable that at least one surface of the metal foil layer (preferably the glossy surface of the metal foil layer 3) has these maximum reflected light intensity B values. In order to adjust the maximum reflected light intensity B to 300 or more, it is effective to reduce the surface roughness of the rolling roll and adjust the rolling speed so that the convex parts of the fine uneven shape on the surface are not sharp when manufacturing the metal foil layer, and it is preferable to confirm that the maximum reflected light intensity B of at least one surface of the obtained metal foil layer is 300 or more and use it as the metal foil layer of the exterior material for the electricity storage device of the present disclosure.

Furthermore, from the viewpoint of more suitably exerting the effect of the second aspect of the present disclosure, the maximum slope D in the range of light receiving angles of 45.0° or more and 75.0° or less, measured at every 0.1° of light receiving angle using a goniophotometer under a condition of an incident light angle of 60°, is preferably 200 or more, more preferably 300 or more, even more preferably 400 or more, and even more preferably 470 or more, and the maximum slope D is preferably 600 or less, more preferably 500 or less, and even more preferably 470 or less, and preferred ranges for the maximum slope D include approximately 200 to 600, approximately 200 to 500, approximately 200 to 470, approximately 300 to 600, approximately 300 to 500, approximately 300 to 470, approximately 400 to 600, approximately 400 to 500, approximately 400 to 470, approximately 470 to 600, and approximately 470 to 500. From the viewpoint of more suitably exerting the effects of the second aspect of the present disclosure, it is more preferable that the glossy surface of the metal foil layer 3 has these maximum slope D values. Also, in the above-mentioned first aspect of the present disclosure, it is more preferable that at least one surface of the metal foil layer (preferably the glossy surface of the metal foil layer 3) has these maximum slope D values.

As described above, the surface of the metal foil layer inevitably has a fine uneven shape, and the smaller the value of the maximum slope D is below 200, the sharper the convex or concave portion of the fine uneven shape that the metal foil layer inevitably has. As described above, the sharper the convex or concave portion of the uneven shape on the surface of the metal foil layer, the more likely it is that cracks will occur in the metal foil layer starting from the sharp convex or concave portion when the metal foil layer is stretched during the molding of the exterior material for the electric storage device. In the present disclosure, by controlling the maximum slope D on at least one surface of the metal foil layer to 200 or more, it can be considered that cracks in the metal foil layer during the molding of the exterior material for the electric storage device are suitably suppressed and better formability is exhibited. In order to adjust the value of the maximum slope D to 200 or more, it is effective to adjust the amount of rolling oil and the conveying tension during rolling in order to provide a suitable uneven shape on the surface when manufacturing the metal foil layer.

The graph function for calculating the slopes C and D is y = ((reflected light intensity value at x + 0.5°) - (reflected light intensity value at x)) / 0.5. If the reflected light intensity at a certain angle is A and the reflected light intensity at an angle of +0.5° is B, then calculate (B - A) / 0.5. This calculation is performed over the entire measurement range, and the largest number is taken as the maximum slope value C or D.

<Surface properties of metal foil layer (goniophotometer)>
For each of the surfaces (matte surface and glossy surface) of the metal foil layer of the packaging material for an electricity storage device, the maximum reflected light intensity and maximum tilt value are measured using a goniophotometer as follows.

The metal foil layer can also be removed from each electrical storage device exterior material and measured in this manner using the following procedure. Aluminum alloy foil can also be measured. The base material layer of the electrical storage device exterior material is manually peeled off to produce a laminate consisting of the metal foil layer, an adhesive layer that is laminated as necessary, and a heat-sealable resin layer. This laminate is then immersed in orthodichlorobenzene under the following conditions to remove the adhesive layer, heat-sealable resin layer, etc. from the metal foil layer, and the surface of the metal foil layer is washed multiple times with ethanol and left to dry, resulting in a metal foil layer that is the subject of measurement.

Next, the maximum reflected light intensity and maximum tilt are measured for each surface of the metal foil layer (matte surface and glossy surface) using a goniophotometer under the following measurement conditions.

(Measurement conditions for standard black glass using a variable angle photometer)
Standard black glass (black glass reference plate) was used as a reference for reflected light intensity. Specifically, the measurement value of the goniophotometer varies depending on the individual difference of the lamp and the usage condition of the lamp. In order to enable absolute evaluation of the sample, the maximum reflected light intensity of the black glass (black glass reference plate) is set as 100, and the reflected light intensity of the sample is normalized.
Measurement target: Black glass reference plate BK-7 (black glass reference plate, refractive index 1.518) manufactured by Murakami Color Research Laboratory Co., Ltd.
Equipment: Variangular photometer Incident angle (IA): 60°
Receiving angle: +50° to +70°, measured in 0.1° increments. Facing angle (FA): 0°
Incident light aperture (VS1): 3 (10.5 mm)
Aperture (VS3): 4 (9.1 mm)
SENSITIVITY: 950
HIGH VOLT.: 539 (adjusted so that the reflection intensity of black glass (black glass reference plate) is 85)
Neutral density filters: 1% filter, 50% filter

(Measurement conditions for the variable angle photometer (matte surface))
Measurements are carried out under conditions where the reflection intensity from standard black glass (black glass reference plate) is 85. Only the light-reducing filter is changed as necessary so that the reflection intensity is 90 or less.
Equipment: Goniophotometer Sample fixing: Fix the sample on a suction sample stage. (The average value is taken for n=5 or more samples.) If a suction sample stage is not available, attach the sample to black-colored glass with double-sided tape and cover the periphery with black tape, and take the average value for n=5 or more samples.
Incident angle (IA): 60°
Receiving angle: 0 to +90°, measured in 0.1° increments. Facing angle (FA): 0°
Incident light aperture (VS1): 3 (10.5 mm)
Aperture (VS3): 4 (9.1 mm)
SENSITIVITY: 950
HIGH VOLT.: 539 (Use a value adjusted so that the reflection intensity of standard black plate glass (black glass reference plate BK-7 refractive index 1.518) is 85)
Neutral density filter: Measurements are performed under conditions where the reflection intensity is 85 with standard black glass (black glass reference plate). Change only the neutral density filter as necessary so that the reflection intensity is 90 or less. If the reflection intensity is weaker than that of black glass (black glass reference plate) and falls below 10, adjust with a 1% filter only, a 10% filter only, a 50% filter only, or a combination of a 10% filter and a 50% filter. If the reflection intensity is stronger than that of black glass (black glass reference plate), adjust with a 10% filter and a 50% filter, or a combination of a 1% filter, a 10% filter, and a 50% filter.
Incident direction: Parallel to the rolling direction of the aluminum alloy foil

(Measurement conditions for the variable angle photometer (glossy surface))
Equipment: Commercial product Sample fixation: Fix the sample with a suction sample stage (sample number n = 5 or more and take the average value). If a suction sample stage is not available, attach the sample to a black-colored glass with double-sided tape and cover the periphery with black tape, and take the average value with sample number n = 5 or more.
Incident angle (IA): 60°
Receiving angle: +45° to +75°, measured in 0.1° increments. Facing angle (FA): 0°
Incident light aperture (VS1): 3 (10.5 mm)
Aperture (VS3): 4 (9.1 mm)
SENSITIVITY: 950
HIGH VOLT.: 539 (Use a value adjusted so that the reflection intensity of standard black plate glass (black glass reference plate BK-7 refractive index 1.518) is 85)
Neutral density filter: Measurements are carried out under conditions where the reflection intensity is 85 with black glass (black glass reference plate). Change only the neutral density filter as necessary so that the reflection intensity is 90 or less. If the reflection intensity is weaker than that of standard black glass (black glass reference plate) and falls below 10, adjust with a 1% filter only, a 10% filter only, a 50% filter only, or a combination of a 10% filter and a 50% filter. If the reflection intensity is stronger than that of standard black glass (black glass reference plate), adjust with a 10% filter and a 50% filter, or a combination of a 1% filter, a 10% filter, and a 50% filter.
Incident direction: Parallel to the rolling direction of the aluminum alloy foil

From the viewpoint of improving the formability of the exterior material for the power storage device, the aluminum alloy foil is preferably a soft aluminum alloy foil made of, for example, an annealed aluminum alloy, and from the viewpoint of further improving the formability, it is preferable that the aluminum alloy foil is an iron-containing aluminum alloy foil. In the iron-containing aluminum alloy foil (100% by mass), the iron content is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 0.7% by mass or more, even more preferably 1.2% by mass or more, and is preferably 9.0% by mass or less, more preferably 2.0% by mass or less, even more preferably 1.7% by mass or less, even more preferably 1.3% by mass or less, and the preferred ranges are about 0.1 to 9.0% by mass, 0.1 Examples of the iron content include about 0.1 to 2.0% by mass, about 0.1 to 1.7% by mass, about 0.1 to 1.3% by mass, about 0.5 to 9.0% by mass, about 0.5 to 2.0% by mass, about 0.5 to 1.7% by mass, about 0.5 to 1.3% by mass, about 0.7 to 9.0% by mass, about 0.7 to 2.0% by mass, about 0.7 to 1.7% by mass, about 0.7 to 1.3% by mass, about 1.2 to 9.0% by mass, about 1.2 to 2.0% by mass, about 1.2 to 1.7% by mass, and about 1.2 to 1.3% by mass. By having an iron content of 0.1% by mass or more, it is possible to obtain an exterior material for a power storage device having better formability. By having an iron content of 9.0% by mass or less, it is possible to obtain an exterior material for a power storage device having better flexibility. Furthermore, silicon, magnesium, copper, manganese, and the like may be added as necessary. Furthermore, softening can be performed by annealing treatment or the like.

Examples of soft aluminum alloy foils include aluminum alloy foils having a composition specified in JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, or JIS H4000:2014 A8079P-O. The composition of JIS A8021 (JIS H4160:1994 A8021H-O, JIS H4000:2014 A8021P-O) is specified as follows: Si is 0.15 mass% or less, Fe is 1.2 to 1.7 mass%, Cu is 0.05 mass% or less, other components (components other than Si, Fe, Cu, and Al) are each 0.05 mass% or less, the total of the other components is 0.15 mass% or less, and Al is the balance. In addition, the composition of JIS A8079 (JIS H4160:1994 A8079H-O, JIS H4000:2014 A8079P-O) is specified as follows: Si is 0.05-0.30 mass%, Fe is 0.7-1.3 mass%, Cu is 0.05 mass% or less, Zn is 0.10 mass% or less, other components (components other than Si, Fe, Cu, Zn, and Al) are each 0.05 mass% or less, the total of other components is 0.15 mass% or less, and Al is the balance. The composition of aluminum alloy foil can be measured by elemental analysis.

From the viewpoint of more optimally exerting the effects of the present disclosure, the Si content of the aluminum alloy foil is preferably 0.08 mass% or more, more preferably about 0.10 mass% or more, even more preferably about 0.12 mass% or more, and is preferably about 1.50 mass% or less, more preferably about 1.20 mass% or less, and even more preferably about 1.00 mass% or less, and preferred ranges include approximately 0.08 to 1.50 mass%, approximately 0.08 to 1.20 mass%, approximately 0.08 to 1.00 mass%, approximately 0.10 to 1.50 mass%, approximately 0.10 to 1.20 mass%, approximately 0.10 to 1.00 mass%, approximately 0.12 to 1.50 mass%, approximately 0.12 to 1.20 mass%, and approximately 0.12 to 1.00 mass%. Among aluminum alloy foils satisfying these Si contents, the Fe content is preferably 0.50 mass% or more, more preferably about 0.80 mass% or more, and even more preferably about 1.00 mass% or more, and is preferably about 1.50 mass% or less, more preferably about 1.40 mass% or less, and even more preferably about 1.30 mass% or less. Preferred ranges include about 0.50 to 1.50 mass%, about 0.50 to 1.40 mass%, about 0.50 to 1.30 mass%, about 0.80 to 1.50 mass%, about 0.80 to 1.4 ... Examples of the Mg content include about 0 mass%, about 0.80 to 1.30 mass%, about 1.00 to 1.50 mass%, about 1.00 to 1.40 mass%, and about 1.00 to 1.30 mass%. The Mg content is preferably 0 mass% or more, more preferably 0.80 mass% or more, and is preferably 2.00 mass% or less, more preferably 1.50 mass% or less. Preferred ranges include about 0 to 2.00 mass%, about 0 to 1.50 mass%, about 0.80 to 2.00 mass%, and about 0.80 to 1.50 mass%, and may be 0 mass%. The Al content is preferably 95.00% by mass or more, more preferably about 95.30% by mass or more, and even more preferably about 95.50% by mass or more, and is also preferably about 97.00% by mass or less, more preferably about 96.30% by mass or less, and even more preferably about 95.60% by mass or less. Preferred ranges include about 95.00 to 97.00% by mass, about 95.00 to 96.30% by mass, about 95.00 to 95.60% by mass, about 95.30 to 97.00% by mass, about 95.30 to 96.30% by mass, and about 95.30 to 95.60% by mass. It is preferable that each of the other components (components other than Si, Fe, Mg, and Al) is 0.05% by mass or less, the total of the other components is 0.15% by mass or less, and Al is the remainder.

Furthermore, examples of stainless steel foil include austenitic, ferritic, austenitic-ferritic, martensitic, and precipitation hardened stainless steel foils. Furthermore, from the viewpoint of providing an exterior material for an electricity storage device with excellent formability, it is preferable that the stainless steel foil is made of austenitic stainless steel.

Specific examples of austenitic stainless steels that make up the stainless steel foil include SUS304, SUS301, and SUS316L, with SUS304 being particularly preferred.

The thickness of the metal foil layer 3, in the case of metal foil, is sufficient as long as it at least functions as a metal foil layer to prevent the intrusion of moisture, and may be, for example, about 9 to 200 μm. The thickness of the metal foil layer 3 is preferably about 85 μm or less, more preferably about 50 μm or less, even more preferably about 40 μm or less, and particularly preferably about 35 μm or less. The thickness of the metal foil layer 3 is preferably about 10 μm or more, even more preferably about 20 μm or more, and more preferably about 25 μm or more. The preferred ranges for the thickness of the metal foil layer 3 include about 10 to 85 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 35 μm, about 20 to 85 μm, about 20 to 50 μm, about 20 to 40 μm, about 20 to 35 μm, about 25 to 85 μm, about 25 to 50 μm, about 25 to 40 μm, and about 25 to 35 μm. When the metal foil layer 3 is made of an aluminum alloy foil, the above-mentioned range is particularly preferred. From the viewpoint of imparting high formability and high rigidity to the exterior material 10 for an electric storage device, the thickness of the metal foil layer 3 is preferably about 35 μm or more, more preferably about 45 μm or more, even more preferably about 50 μm or more, and even more preferably about 55 μm or more, and is preferably about 200 μm or less, more preferably about 85 μm or less, even more preferably about 75 μm or less, and even more preferably about 70 μm or less. Preferred ranges are about 35 to 200 μm, about 35 to 85 μm, about 35 to 75 μm, about 35 to 70 μm, about 45 to 200 μm, about 45 to 85 μm, about 45 to 75 μm, about 45 to 70 μm, about 50 to 200 μm, about 50 to 85 μm, about 50 to 75 μm, about 50 to 70 μm, about 55 to 200 μm, about 55 to 85 μm, about 55 to 75 μm, and about 55 to 70 μm. By providing the exterior material 10 for an electric storage device with high formability, deep drawing can be easily performed, which can contribute to increasing the capacity of the electric storage device. In addition, when the capacity of the electric storage device is increased, the weight of the electric storage device increases, but the rigidity of the exterior material 10 for an electric storage device is increased, which can contribute to high sealing of the electric storage device. In particular, when the metal foil layer 3 is made of stainless steel foil, the thickness of the stainless steel foil is preferably about 60 μm or less, more preferably about 50 μm or less, even more preferably about 40 μm or less, even more preferably about 30 μm or less, and particularly preferably about 25 μm or less. The thickness of the stainless steel foil is preferably about 10 μm or more, more preferably about 15 μm or more. Preferred ranges for the thickness of the stainless steel foil include about 10 to 60 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 30 μm, about 10 to 25 μm, about 15 to 60 μm, about 15 to 50 μm, about 15 to 40 μm, about 15 to 30 μm, and about 15 to 25 μm.

In addition, the metal foil layer 3 is preferably provided with a corrosion-resistant film at least on the surface opposite to the base layer in order to prevent dissolution and corrosion. The metal foil layer 3 may be provided with a corrosion-resistant film on both sides. Here, the corrosion-resistant film refers to a thin film that is provided with corrosion resistance (e.g., acid resistance, alkali resistance, etc.) by performing, for example, hydrothermal transformation treatment such as boehmite treatment, chemical conversion treatment, anodizing treatment, plating treatment with nickel or chromium, or corrosion prevention treatment by applying a coating agent on the surface of the metal foil layer. Specifically, the corrosion-resistant film means a film that improves the acid resistance of the metal foil layer (acid-resistant film), a film that improves the alkali resistance of the metal foil layer (alkali-resistant film), etc. The treatment for forming the corrosion-resistant film may be one type, or two or more types may be combined. In addition to one layer, multiple layers can be formed. Furthermore, among these treatments, the hydrothermal transformation treatment and the anodizing treatment are treatments in which the metal foil surface is dissolved by a treatment agent to form a metal compound with excellent corrosion resistance. These treatments may also be included in the definition of chemical conversion treatment. Also, if the metal foil layer 3 has a corrosion-resistant coating, the corrosion-resistant coating is included in the metal foil layer 3.

The corrosion-resistant coating prevents delamination between the metal foil layer (e.g., aluminum alloy foil) and the base layer during molding of the exterior material for the power storage device, prevents dissolution and corrosion of the surface of the metal foil layer due to hydrogen fluoride produced by the reaction between the electrolyte and moisture, and in particular prevents dissolution and corrosion of aluminum oxide present on the surface of the metal foil layer when the metal foil layer is an aluminum alloy foil, and improves the adhesion (wettability) of the surface of the metal foil layer, preventing delamination between the base layer and metal foil layer during heat sealing and between the base layer and metal foil layer during molding.

Various corrosion-resistant films formed by chemical conversion treatments are known, including mainly corrosion-resistant films containing at least one of phosphates, chromates, fluorides, triazine thiol compounds, and rare earth oxides. Chemical conversion treatments using phosphates and chromates include, for example, chromate chromate treatment, phosphoric acid chromate treatment, phosphoric acid-chromate treatment, and chromate treatment. Examples of chromium compounds used in these treatments include chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium biphosphate, chromate acetyl acetate, chromium chloride, and potassium chromium sulfate. Examples of phosphorus compounds used in these treatments include sodium phosphate, potassium phosphate, ammonium phosphate, and polyphosphoric acid. Examples of chromate treatments include etching chromate treatment, electrolytic chromate treatment, and coating-type chromate treatment, with coating-type chromate treatment being preferred. In this coating type chromate treatment, at least the inner surface of a metal foil layer (e.g., aluminum alloy foil) is first degreased by a known method such as an alkali immersion method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, or an acid activation method, and then the degreased surface is coated with a treatment liquid mainly composed of a metal phosphate such as Cr (chromium) phosphate, Ti (titanium) phosphate, Zr (zirconium) phosphate, or Zn (zinc) phosphate, or a mixture of these metal salts, or a treatment liquid mainly composed of a nonmetallic phosphate and a mixture of these nonmetallic salts, or a treatment liquid consisting of a mixture of these with a synthetic resin, or the like, by a known coating method such as a roll coating method, a gravure printing method, or a dipping method, and then dried. As the treatment liquid, various solvents such as water, alcohol-based solvents, hydrocarbon-based solvents, ketone-based solvents, ester-based solvents, and ether-based solvents can be used, and water is preferred. The resin component used here may be a polymer such as a phenolic resin or an acrylic resin, and may be a chromate treatment using an aminated phenolic polymer having a repeating unit represented by the following general formulas (1) to (4). In the aminated phenolic polymer, the repeating units represented by the following general formulas (1) to (4) may be contained alone or in any combination of two or more. The acrylic resin is preferably polyacrylic acid, acrylic acid methacrylic acid ester copolymer, acrylic acid maleic acid copolymer, acrylic acid styrene copolymer, or a derivative thereof such as a sodium salt, an ammonium salt, or an amine salt. In particular, a derivative of polyacrylic acid such as an ammonium salt, a sodium salt, or an amine salt of polyacrylic acid is preferable. In the present disclosure, polyacrylic acid means a polymer of acrylic acid. The acrylic resin is also preferably a copolymer of acrylic acid and a dicarboxylic acid or a dicarboxylic anhydride, and is also preferably an ammonium salt, a sodium salt, or an amine salt of a copolymer of acrylic acid and a dicarboxylic acid or a dicarboxylic anhydride. Only one type of acrylic resin may be used, or two or more types may be mixed and used.

In the general formulae (1) to (4), X represents a hydrogen atom, a hydroxy group, an alkyl group, a hydroxyalkyl group, an allyl group, or a benzyl group. R ¹ and R ² may be the same or different and represent a hydroxy group, an alkyl group, or a hydroxyalkyl group. In the general formulae (1) to (4), examples of the alkyl group represented by X, R ¹ , and R ² include linear or branched alkyl groups having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group. Examples of the hydroxyalkyl group represented by X, R ^1, and R ² include linear or branched alkyl groups having 1 to 4 carbon atoms and substituted with one hydroxy group, such as a hydroxymethyl group, a 1-hydroxyethyl group, a 2-hydroxyethyl group, a 1-hydroxypropyl group, a 2-hydroxypropyl group, a 3-hydroxypropyl group, a 1-hydroxybutyl group, a 2-hydroxybutyl group, a 3-hydroxybutyl group, and a 4-hydroxybutyl group. In the general formulae (1) to (4), the alkyl groups and hydroxyalkyl groups represented by X, R ^1, and R ² may be the same or different. In the general formulae (1) to (4), X is preferably a hydrogen atom, a hydroxy group, or a hydroxyalkyl group. The number average molecular weight of the aminated phenol polymer having the repeating units represented by the general formulae (1) to (4) is preferably about 500 to 1,000,000, for example, and more preferably about 1,000 to 20,000. The aminated phenol polymer is produced, for example, by polycondensing a phenol compound or a naphthol compound with formaldehyde to produce a polymer consisting of the repeating units represented by the general formula (1) or (3), and then introducing a functional group (-CH ₂ NR ¹ R ² ) into the polymer obtained above using formaldehyde and an amine (R ¹ R ² NH). The aminated phenol polymer may be used alone or in combination of two or more types.

Other examples of corrosion-resistant films include thin films formed by a coating-type corrosion prevention treatment in which a coating agent containing at least one selected from the group consisting of rare earth element oxide sol, anionic polymer, and cationic polymer is applied. The coating agent may further contain phosphoric acid or phosphate, and a crosslinking agent for crosslinking the polymer. The rare earth element oxide sol has rare earth element oxide fine particles (e.g., particles with an average particle size of 100 nm or less) dispersed in a liquid dispersion medium. Examples of rare earth element oxides include cerium oxide, yttrium oxide, neodymium oxide, and lanthanum oxide, and cerium oxide is preferred from the viewpoint of further improving adhesion. The rare earth element oxide contained in the corrosion-resistant film can be used alone or in combination of two or more types. Examples of liquid dispersion media for the rare earth element oxide sol include various solvents such as water, alcohol-based solvents, hydrocarbon-based solvents, ketone-based solvents, ester-based solvents, and ether-based solvents, and water is preferred. As the cationic polymer, for example, polyethyleneimine, an ionic polymer complex consisting of a polymer having polyethyleneimine and a carboxylic acid, a primary amine grafted acrylic resin in which a primary amine is graft-polymerized to an acrylic main skeleton, polyallylamine or a derivative thereof, aminated phenol, etc. are preferable. As the anionic polymer, poly(meth)acrylic acid or a salt thereof, or a copolymer mainly composed of (meth)acrylic acid or a salt thereof is preferable. Furthermore, it is preferable that the crosslinking agent is at least one selected from the group consisting of a compound having any one of the functional groups of an isocyanate group, a glycidyl group, a carboxyl group, and an oxazoline group, and a silane coupling agent. Furthermore, it is preferable that the phosphoric acid or the phosphoric acid salt is a condensed phosphoric acid or a condensed phosphate salt.

One example of a corrosion-resistant coating is one formed by applying a solution of fine particles of metal oxides such as aluminum oxide, titanium oxide, cerium oxide, and tin oxide, or barium sulfate dispersed in phosphoric acid to the surface of a metal foil layer and baking the coating at 150°C or higher.

If necessary, the corrosion-resistant coating may have a laminated structure in which at least one of a cationic polymer and an anionic polymer is further laminated. Examples of the cationic polymer and anionic polymer include those described above.

The composition of the corrosion-resistant coating can be analyzed, for example, using time-of-flight secondary ion mass spectrometry.

The amount of the corrosion-resistant coating formed on the surface of the metal foil layer 3 in the chemical conversion treatment is not particularly limited, but for example, in the case of performing a coating-type chromate treatment, it is desirable that the chromate compound is contained in an ^amount , calculated as chromium, of about 0.5 to 50 mg, preferably about 1.0 to 40 mg, the phosphorus compound is contained in an amount, calculated as phosphorus, of about 0.5 to 50 mg, preferably about 1.0 to 40 mg, and the aminated phenol polymer is contained in an amount, calculated as phosphorus, of about 1.0 to 200 mg, preferably about 5.0 to 150 mg, per 1 m2 of the surface of the metal foil layer 3.

The thickness of the corrosion-resistant film is not particularly limited, but is preferably about 1 nm to 20 μm, more preferably about 1 nm to 100 nm, and even more preferably about 1 nm to 50 nm, from the viewpoint of the cohesive force of the film and the adhesive force with the metal foil layer and the heat-sealable resin layer. The thickness of the corrosion-resistant film can be measured by observation with a transmission electron microscope, or by a combination of observation with a transmission electron microscope and energy dispersive X-ray spectroscopy or electron energy loss spectroscopy. By analyzing the composition of the corrosion-resistant film using time-of-flight secondary ion mass spectrometry, for example, a peak derived from a secondary ion composed of Ce, P, and O (for example, at least one of Ce ₂ PO ₄ ⁺ and CePO ₄ ^- ) or a secondary ion composed of Cr, P, and O (for example, at least one of CrPO ₂ ⁺ and CrPO ₄ ^- ) is detected.

The chemical conversion treatment is carried out by applying a solution containing a compound used to form a corrosion-resistant film to the surface of the metal foil layer by bar coating, roll coating, gravure coating, immersion, or other methods, and then heating the metal foil layer to a temperature of about 70 to 200°C. In addition, before applying the chemical conversion treatment to the metal foil layer, the metal foil layer may be subjected to a degreasing treatment using an alkali immersion method, electrolytic cleaning method, acid cleaning method, electrolytic acid cleaning method, or other method. By carrying out a degreasing treatment in this manner, it is possible to carry out the chemical conversion treatment of the surface of the metal foil layer more efficiently. In addition, by using an acid degreasing agent in which a fluorine-containing compound is dissolved in an inorganic acid for the degreasing treatment, it is possible to not only degrease the metal foil but also form a fluoride of the metal, which is in a passive state, and in such cases, only the degreasing treatment may be carried out.

[Thermofusible resin layer 4]
In the exterior packaging material for an electricity storage device according to the present disclosure, the heat-sealable resin layer 4 corresponds to the innermost layer, and has the function of sealing the electricity storage device elements by heat-sealing the heat-sealable resin layers to each other when assembling the electricity storage device. It is a layer (sealant layer) that exhibits the above-mentioned properties.

The resin constituting the heat-sealable resin layer 4 is not particularly limited as long as it is heat-sealable, but is preferably a resin containing a polyolefin skeleton such as polyolefin or acid-modified polyolefin. The resin constituting the heat-sealable resin layer 4 can be analyzed to contain a polyolefin skeleton, for example, by infrared spectroscopy, gas chromatography mass spectrometry, etc. In addition, when the resin constituting the heat-sealable resin layer 4 is analyzed by infrared spectroscopy, it is preferable that a peak derived from maleic anhydride is detected. For example, when maleic anhydride-modified polyolefin is measured by infrared spectroscopy, a peak derived from maleic anhydride is detected near the wave number 1760 cm ^-1 and near the wave number 1780 cm ^-1 . When the heat-sealable resin layer 4 is a layer composed of maleic anhydride-modified polyolefin, a peak derived from maleic anhydride is detected by infrared spectroscopy. However, if the degree of acid modification is low, the peak may be small and not detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

The heat-sealable resin layer 4 preferably contains a resin containing a polyolefin skeleton as a main component, more preferably contains polyolefin as a main component, and even more preferably contains polypropylene as a main component. Here, the main component means that the content of the resin components contained in the heat-sealable resin layer 4 is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more. For example, the heat-sealable resin layer 4 containing polypropylene as a main component means that the content of polypropylene among the resin components contained in the heat-sealable resin layer 4 is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more.

Specific examples of polyolefins include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; ethylene-α-olefin copolymers; polypropylenes such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); propylene-α-olefin copolymers; and ethylene-butene-propylene terpolymers. Among these, polypropylene is preferred. When the polyolefin resin is a copolymer, it may be a block copolymer or a random copolymer. These polyolefin resins may be used alone or in combination of two or more types.

The polyolefin may also be a cyclic polyolefin. Cyclic polyolefins are copolymers of olefins and cyclic monomers, and examples of olefins that are constituent monomers of the cyclic polyolefins include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, and isoprene. Examples of cyclic monomers that are constituent monomers of cyclic polyolefins include cyclic alkenes such as norbornene; and cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these, cyclic alkenes are preferred, and norbornene is more preferred.

The polyolefin may be an acid-modified polyolefin. An acid-modified polyolefin is a polymer modified by block polymerization or graft polymerization of a polyolefin with an acid component. The polyolefin to be acid-modified may be the above-mentioned polyolefin, a copolymer obtained by copolymerizing the above-mentioned polyolefin with a polar molecule such as acrylic acid or methacrylic acid, or a polymer such as a cross-linked polyolefin. Examples of the acid component used for the acid modification include carboxylic acids or anhydrides such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride.

The acid-modified polyolefin may be an acid-modified cyclic polyolefin. An acid-modified cyclic polyolefin is a polymer obtained by copolymerizing a part of the monomers constituting the cyclic polyolefin by replacing it with an acid component, or by block polymerizing or graft polymerizing an acid component onto a cyclic polyolefin. The cyclic polyolefin to be acid-modified is the same as described above. The acid component used for the acid modification is the same as the acid component used for the modification of the polyolefin described above.

Preferred acid-modified polyolefins include polyolefins modified with carboxylic acids or their anhydrides, polypropylenes modified with carboxylic acids or their anhydrides, maleic anhydride-modified polyolefins, and maleic anhydride-modified polypropylenes.

The heat-sealable resin layer 4 may be formed of one type of resin alone, or may be formed of a blend polymer of two or more types of resin. Furthermore, the heat-sealable resin layer 4 may be formed of only one layer, or may be formed of two or more layers of the same or different resins.

When manufacturing the exterior material 10 for an electricity storage device of the present disclosure by laminating the heat-sealable resin layer 4 with the metal foil layer 3, the adhesive layer 5, etc., a preformed resin film may be used as the heat-sealable resin layer 4. In addition, the heat-sealable resin that forms the heat-sealable resin layer 4 may be formed into a film on the surface of the metal foil layer 3, the adhesive layer 5, etc. by extrusion molding, coating, etc., to form the heat-sealable resin layer 4 from the resin film.

The heat-sealable resin layer 4 may also contain a lubricant, etc., if necessary. When the heat-sealable resin layer 4 contains a lubricant, the moldability of the exterior material for the power storage device can be improved. There are no particular limitations on the lubricant, and any known lubricant can be used.

The lubricant is not particularly limited, but preferably an amide-based lubricant is used. Specific examples of the lubricant include those exemplified for the base layer 1. The lubricant may be used alone or in combination of two or more types, and it is preferable to use a combination of two or more types.

In the present disclosure, from the viewpoint of improving the formability of the exterior material for a power storage device, it is preferable that a lubricant is present on at least one of the surface and the inside of the heat-sealable resin layer 4. The lubricant is not particularly limited, but preferably includes amide-based lubricants. Specific examples of amide-based lubricants include, for example, saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides. Specific examples of saturated fatty acid amides include lauric acid amides, palmitic acid amides, stearic acid amides, behenic acid amides, and hydroxystearic acid amides. Specific examples of unsaturated fatty acid amides include oleic acid amides and erucic acid amides. Specific examples of substituted amides include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, and N-stearyl erucic acid amide. Specific examples of methylol amides include methylol stearic acid amide. Specific examples of saturated fatty acid bisamides include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbehenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N,N'-distearyl adipic acid amide, N,N'-distearyl sebacic acid amide, etc. Specific examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyl adipic acid amide, N,N'-dioleyl sebacic acid amide, etc. Specific examples of fatty acid ester amides include stearamide ethyl stearate, etc. Specific examples of aromatic bisamides include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, and N,N'-distearylisophthalic acid amide. The lubricant may be used alone or in combination of two or more types, preferably in combination of two or more types.

When a lubricant is present on the surface of the heat-fusible resin layer 4, the amount thereof is not particularly limited, but from the viewpoint of improving the moldability of the exterior material for a storage battery device, it is preferably about 1 mg / m ² or more, more preferably about 3 mg / m ² or more, even more preferably about 5 mg / m ^{2 or} more, even more preferably about 10 mg / m ² or more, and even more preferably about 15 mg / m ² or more, and also preferably about 50 mg / m ² or less, and even more preferably about 40 mg / m ² or less, and preferred ranges include about 1 to 50 mg / m ² , about 1 to 40 mg / m ² , about 3 to 50 mg / m ² , about 3 to 40 mg / m ² , about 5 to 50 mg / m ² , about 5 to 40 mg / m ² , about 10 to 50 mg / m ² , about 10 to 40 mg / m ² , about 15 to 50 mg / m ² , and about 15 to 40 mg / m ² .

When a lubricant is present inside the heat-sealable resin layer 4, the amount thereof is not particularly limited, but from the viewpoint of improving the formability of the exterior material for an electrical storage device, it is preferably at least about 100 ppm, more preferably at least about 300 ppm, even more preferably at least about 500 ppm, and is preferably at most about 3000 ppm, more preferably at most about 2000 ppm, and preferred ranges include about 100-3000 ppm, about 100-2000 ppm, about 300-3000 ppm, about 300-2000 ppm, about 500-3000 ppm, and about 500-2000 ppm. When two or more types of lubricant are present inside the heat-sealable resin layer 4, the above amount of lubricant is the total amount of lubricant. Furthermore, when two or more types of lubricants are present inside the heat-sealable resin layer 4, the amount of the first type of lubricant is not particularly limited, but from the viewpoint of improving the formability of the exterior material for an electrical storage device, it is preferably about 100 ppm or more, more preferably about 300 ppm or more, and even more preferably about 500 ppm or more, and is preferably about 3000 ppm or less, more preferably about 2000 ppm or less, and preferred ranges include about 100 to 3000 ppm, about 100 to 2000 ppm, about 300 to 3000 ppm, about 300 to 2000 ppm, about 500 to 3000 ppm, and about 500 to 2000 ppm. The amount of the second type of lubricant is not particularly limited, but from the viewpoint of improving the moldability of the exterior material for an electrical storage device, it is preferably about 50 ppm or more, more preferably about 100 ppm or more, and even more preferably about 200 ppm or more, and is preferably about 1500 ppm or less, more preferably about 1000 ppm or less, and preferred ranges include about 50 to 1500 ppm, about 50 to 1000 ppm, about 100 to 1500 ppm, about 100 to 1000 ppm, about 200 to 1500 ppm, and about 200 to 1000 ppm.

The lubricant present on the surface of the heat-sealable resin layer 4 may be a lubricant exuded from the resin that constitutes the heat-sealable resin layer 4, or a lubricant applied to the surface of the heat-sealable resin layer 4.

The thickness of the heat-sealable resin layer 4 is not particularly limited as long as the heat-sealable resin layers are heat-sealed to each other to seal the electricity storage device element, but may be, for example, about 100 μm or less, preferably about 85 μm or less, and more preferably about 15 to 85 μm. For example, when the thickness of the adhesive layer 5 described below is 10 μm or more, the thickness of the heat-sealable resin layer 4 is preferably about 85 μm or less, and more preferably about 15 to 45 μm. For example, when the thickness of the adhesive layer 5 described below is less than 10 μm or when the adhesive layer 5 is not provided, the thickness of the heat-sealable resin layer 4 is preferably about 20 μm or more, and more preferably about 35 to 85 μm.

[Adhesive layer 5]
In the packaging material for an electricity storage device of the present disclosure, the adhesive layer 5 is a layer that is provided, if necessary, between the metal foil layer 3 (or the corrosion-resistant film) and the heat-sealable resin layer 4 in order to firmly bond them together.

The adhesive layer 5 is formed from a resin capable of bonding the metal foil layer 3 and the heat-sealable resin layer 4. The resin used to form the adhesive layer 5 may be, for example, the same adhesive as exemplified for the adhesive layer 2.

In addition, from the viewpoint of firmly adhering the adhesive layer 5 and the heat-sealable resin layer 4, the resin used to form the adhesive layer 5 preferably contains a polyolefin skeleton, and examples of the resin include the polyolefin, acid-modified polyolefin, cyclic polyolefin, and acid-modified cyclic polyolefin exemplified in the heat-sealable resin layer 4 described above. On the other hand, from the viewpoint of firmly adhering the metal foil layer 3 and the adhesive layer 5, the adhesive layer 5 preferably contains an acid-modified polyolefin. Examples of the acid-modified component include dicarboxylic acids such as maleic acid, itaconic acid, succinic acid, and adipic acid, and their anhydrides, acrylic acid, and methacrylic acid, but maleic anhydride is most preferred in terms of ease of modification and versatility. In addition, from the viewpoint of the heat resistance of the exterior material for the electric storage device, the olefin component is preferably a polypropylene-based resin, and the adhesive layer 5 most preferably contains maleic anhydride-modified polypropylene.

When the resin used to form the adhesive layer 5 contains a polyolefin skeleton, the adhesive layer 5 preferably contains a resin containing a polyolefin skeleton as a main component, more preferably contains an acid-modified polyolefin as a main component, and even more preferably contains an acid-modified polypropylene as a main component. Here, the main component means that the content of the resin components contained in the adhesive layer 5 is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more. For example, when the adhesive layer 5 contains acid-modified polypropylene as a main component, it means that the content of the acid-modified polypropylene among the resin components contained in the adhesive layer 5 is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more.

The resin constituting the adhesive layer 5 can be analyzed for polyolefin skeleton by infrared spectroscopy, gas chromatography mass spectrometry, or the like, and the analysis method is not particularly limited. The resin constituting the adhesive layer 5 can be analyzed for acid-modified polyolefin by, for example, measuring maleic anhydride-modified polyolefin by infrared spectroscopy, whereby peaks derived from maleic anhydride are detected at wave numbers of about 1760 cm ^-1 and about 1780 cm ^-1 . However, if the degree of acid modification is low, the peaks may become small and not be detected. In that case, analysis can be performed by nuclear magnetic resonance spectroscopy.

Furthermore, from the viewpoint of ensuring durability such as heat resistance and resistance to contents of the exterior material for the power storage device, and of ensuring moldability while reducing the thickness, it is more preferable that the adhesive layer 5 is a cured product of a resin composition containing an acid-modified polyolefin and a curing agent. Preferred examples of the acid-modified polyolefin include those mentioned above.

The adhesive layer 5 is preferably a cured product of a resin composition containing an acid-modified polyolefin and at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and a compound having an epoxy group, and is particularly preferably a cured product of a resin composition containing an acid-modified polyolefin and at least one selected from the group consisting of a compound having an isocyanate group and a compound having an epoxy group. The adhesive layer 5 preferably contains at least one selected from the group consisting of polyurethane, polyester, and epoxy resin, and more preferably contains polyurethane and epoxy resin. As the polyester, for example, an ester resin formed by the reaction of an epoxy group with a maleic anhydride group, and an amide ester resin formed by the reaction of an oxazoline group with a maleic anhydride group are preferable. In addition, when unreacted substances of a curing agent such as a compound having an isocyanate group, a compound having an oxazoline group, or an epoxy resin remain in the adhesive layer 5, the presence of the unreacted substances can be confirmed by a method selected from, for example, infrared spectroscopy, Raman spectroscopy, time-of-flight secondary ion mass spectrometry (TOF-SIMS), etc.

In order to further increase the adhesion between the metal foil layer 3 and the adhesive layer 5, the adhesive layer 5 is preferably a cured product of a resin composition containing a curing agent having at least one selected from the group consisting of an oxygen atom, a heterocycle, a C=N bond, and a C-O-C bond. Examples of curing agents having a heterocycle include curing agents having an oxazoline group and curing agents having an epoxy group. Examples of curing agents having a C=N bond include curing agents having an oxazoline group and curing agents having an isocyanate group. Examples of curing agents having a C-O-C bond include curing agents having an oxazoline group and curing agents having an epoxy group. The fact that the adhesive layer 5 is a cured product of a resin composition containing these curing agents can be confirmed by methods such as gas chromatography mass spectrometry (GCMS), infrared spectroscopy (IR), time-of-flight secondary ion mass spectrometry (TOF-SIMS), and X-ray photoelectron spectroscopy (XPS).

The compound having an isocyanate group is not particularly limited, but from the viewpoint of effectively increasing the adhesion between the metal foil layer 3 and the adhesive layer 5, a polyfunctional isocyanate compound is preferably used. The polyfunctional isocyanate compound is not particularly limited as long as it has two or more isocyanate groups. Specific examples of polyfunctional isocyanate-based curing agents include pentane diisocyanate (PDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymerized or nurated versions of these, mixtures of these, and copolymers with other polymers. Other examples include adducts, biurets, and isocyanurates.

The content of the compound having an isocyanate group in the adhesive layer 5 is preferably in the range of 0.1 to 50 mass % in the resin composition constituting the adhesive layer 5, and more preferably in the range of 0.5 to 40 mass %. This effectively improves the adhesion between the metal foil layer 3 and the adhesive layer 5.

The compound having an oxazoline group is not particularly limited as long as it has an oxazoline skeleton. Specific examples of compounds having an oxazoline group include those having a polystyrene main chain and those having an acrylic main chain. In addition, examples of commercially available products include the Epocross series manufactured by Nippon Shokubai Co., Ltd.

The proportion of the compound having an oxazoline group in the adhesive layer 5 is preferably in the range of 0.1 to 50 mass %, and more preferably in the range of 0.5 to 40 mass %, in the resin composition constituting the adhesive layer 5. This effectively improves the adhesion between the metal foil layer 3 and the adhesive layer 5.

An example of a compound having an epoxy group is an epoxy resin. There are no particular limitations on the epoxy resin, so long as it is a resin capable of forming a crosslinked structure by the epoxy groups present in the molecule, and any known epoxy resin can be used. The weight average molecular weight of the epoxy resin is preferably about 50 to 2000, more preferably about 100 to 1000, and even more preferably about 200 to 800. In the first disclosure, the weight average molecular weight of the epoxy resin is a value measured by gel permeation chromatography (GPC) under conditions in which polystyrene is used as a standard sample.

Specific examples of epoxy resins include glycidyl ether derivatives of trimethylolpropane, bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, bisphenol F glycidyl ether, novolac glycidyl ether, glycerin polyglycidyl ether, polyglycerin polyglycidyl ether, etc. One type of epoxy resin may be used alone, or two or more types may be used in combination.

The proportion of epoxy resin in the adhesive layer 5 is preferably in the range of 0.1 to 50 mass % in the resin composition constituting the adhesive layer 5, and more preferably in the range of 0.5 to 40 mass %. This effectively improves the adhesion between the metal foil layer 3 and the adhesive layer 5.

The polyurethane is not particularly limited, and any known polyurethane can be used. The adhesive layer 5 may be, for example, a cured product of a two-component curing polyurethane.

The proportion of polyurethane in the adhesive layer 5 is preferably in the range of 0.1 to 50 mass % in the resin composition constituting the adhesive layer 5, and more preferably in the range of 0.5 to 40 mass %. This effectively improves the adhesion between the metal foil layer 3 and the adhesive layer 5 in an atmosphere containing components that induce corrosion of the metal foil layer, such as an electrolyte.

When the adhesive layer 5 is a cured product of a resin composition containing at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and an epoxy resin, and the acid-modified polyolefin, the acid-modified polyolefin functions as a base agent, and the compound having an isocyanate group, the compound having an oxazoline group, and the compound having an epoxy group each function as a curing agent.

The adhesive layer 5 may contain a modifier having a carbodiimide group.

When manufacturing the exterior material 10 for an electricity storage device of the present disclosure by laminating the adhesive layer 5 with the metal foil layer 3, the heat-sealable resin layer 4, etc., a preformed resin film may be used as the adhesive layer 5. In addition, the heat-sealable resin that forms the adhesive layer 5 may be formed into a film on the surface of the metal foil layer 3, the heat-sealable resin layer 4, etc. by extrusion molding, coating, etc., to form the adhesive layer 5 from the resin film.

The thickness of the adhesive layer 5 is preferably about 50 μm or less, about 40 μm or less, about 30 μm or less, about 20 μm or less, or about 5 μm or less. The thickness of the adhesive layer 5 is preferably about 0.1 μm or more, or about 0.5 μm or more. The thickness of the adhesive layer 5 is preferably in the range of about 0.1 to 50 μm, about 0.1 to 40 μm, about 0.1 to 30 μm, about 0.1 to 20 μm, about 0.1 to 5 μm, about 0.5 to 50 μm, about 0.5 to 40 μm, about 0.5 to 30 μm, about 0.5 to 20 μm, or about 0.5 to 5 μm. More specifically, in the case of the adhesive exemplified in the adhesive layer 2 or a cured product of an acid-modified polyolefin and a curing agent, the thickness is preferably about 1 to 10 μm, and more preferably about 1 to 5 μm. In addition, when using a resin exemplified as the heat-sealable resin layer 4, the thickness is preferably about 2 to 50 μm, more preferably about 10 to 40 μm. When the adhesive layer 5 is an adhesive exemplified as the adhesive layer 2 or a cured product of a resin composition containing an acid-modified polyolefin and a curing agent, the adhesive layer 5 can be formed, for example, by applying the resin composition and curing it by heating or the like. In addition, when using a resin exemplified as the heat-sealable resin layer 4, the heat-sealable resin layer 4 and the adhesive layer 5 can be formed, for example, by extrusion molding.

[Surface coating layer 6]
The exterior material for an electricity storage device according to the present disclosure may, if necessary, have a surface coating layer 6 on the substrate layer 1 (the side of the substrate layer 1 opposite to the metal foil layer 3) for the purpose of improving at least one of design, electrolyte resistance, scratch resistance, formability, etc. The surface coating layer 6 is a layer located on the outermost layer side of the exterior material for an electricity storage device when an electricity storage device is assembled using the exterior material for an electricity storage device.

The surface coating layer 6 may be made of, for example, a resin such as polyvinylidene chloride, polyester, polyamide, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, or phenol resin, or a modified product of these resins. It may also be a copolymer of these resins, or a modified product of the copolymer. It may also be a mixture of these resins. The resin is preferably a curable resin. In other words, the surface coating layer 6 is preferably made of a cured product of a resin composition containing a curable resin.

When the resin forming the surface coating layer 6 is a curable resin, the resin may be either a one-component curable type or a two-component curable type, but is preferably a two-component curable type. Examples of two-component curable resins include two-component curable polyurethane, two-component curable polyester, and two-component curable epoxy resin. Among these, two-component curable polyurethane is preferred.

The two-component curing polyurethane may be, for example, a polyurethane containing a first agent containing a polyol compound and a second agent containing an isocyanate compound. Preferably, the two-component curing polyurethane may be a polyurethane containing a polyol such as polyester polyol, polyether polyol, or acrylic polyol as the first agent and an aromatic or aliphatic polyisocyanate as the second agent. In addition, the polyurethane may be, for example, a polyurethane compound in which a polyol compound has been reacted with an isocyanate compound in advance, and a polyurethane containing an isocyanate compound. The polyurethane may be, for example, a polyurethane compound in which a polyol compound has been reacted with an isocyanate compound in advance, and a polyurethane containing a polyol compound. The polyurethane may be, for example, a polyurethane compound in which a polyol compound has been reacted with an isocyanate compound in advance, and a polyurethane containing a polyol compound. The polyurethane may be, for example, a polyurethane compound in which a polyol compound has been reacted with an isocyanate compound in advance, and cured by reacting it with moisture in the air or the like. As the polyol compound, it is preferable to use a polyester polyol having a hydroxyl group on the side chain in addition to the hydroxyl group at the end of the repeating unit. As the second agent, an aliphatic, alicyclic, aromatic, or araliphatic isocyanate compound may be used. Examples of isocyanate compounds include hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), hydrogenated XDI (H6XDI), hydrogenated MDI (H12MDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and naphthalene diisocyanate (NDI). In addition, examples of the isocyanate compounds include polyfunctional isocyanate modified products of one or more of these diisocyanates. In addition, a polymer (e.g., a trimer) can also be used as the polyisocyanate compound. Examples of such polymers include adducts, biurets, and nurates. In addition, an aliphatic isocyanate compound refers to an isocyanate that has an aliphatic group and does not have an aromatic ring, an alicyclic isocyanate compound refers to an isocyanate that has an alicyclic hydrocarbon group, and an aromatic isocyanate compound refers to an isocyanate that has an aromatic ring. The surface coating layer 6 is formed from polyurethane, which gives the exterior material for the electricity storage device excellent electrolyte resistance.

The surface coating layer 6 may contain additives such as lubricants, flame retardants, antiblocking agents, matting agents, antioxidants, light stabilizers, tackifiers, and antistatic agents, depending on the functionality to be provided to the surface of the surface coating layer 6 and its surface, at least on the surface and/or inside the surface coating layer 6, as necessary. Examples of additives include fine particles with an average particle size of about 0.5 nm to 5 μm. The average particle size of the additive is the median size measured by a laser diffraction/scattering type particle size distribution measuring device.

The additive may be either inorganic or organic. There are also no particular limitations on the shape of the additive, and examples include spherical, fibrous, plate-like, amorphous, and scaly shapes.

Specific examples of additives include talc, silica, graphite, kaolin, montmorillonite, mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, neodymium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, alumina, carbon black, carbon nanotubes, high melting point nylon, acrylate resin, cross-linked acrylic, cross-linked styrene, cross-linked polyethylene, benzoguanamine, gold, aluminum, copper, nickel, etc. The additives may be used alone or in combination of two or more. Among these additives, silica, barium sulfate, and titanium oxide are preferable from the viewpoint of dispersion stability and cost. In addition, the additives may be subjected to various surface treatments such as insulation treatment and high dispersion treatment.

The method for forming the surface coating layer 6 is not particularly limited, and examples include a method of applying a resin that forms the surface coating layer 6. When an additive is added to the surface coating layer 6, a resin mixed with the additive may be applied.

In the present disclosure, from the viewpoint of improving the formability of the exterior material for a storage battery device, it is preferable that a lubricant is present on at least one of the surface and the inside of the surface coating layer 6. The lubricant is not particularly limited, but preferably includes amide-based lubricants. Specific examples of amide-based lubricants include, for example, saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides. Specific examples of saturated fatty acid amides include lauric acid amides, palmitic acid amides, stearic acid amides, behenic acid amides, and hydroxystearic acid amides. Specific examples of unsaturated fatty acid amides include oleic acid amides and erucic acid amides. Specific examples of substituted amides include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, and N-stearyl erucic acid amide. Specific examples of methylol amides include methylol stearic acid amide. Specific examples of saturated fatty acid bisamides include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbehenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N,N'-distearyl adipic acid amide, N,N'-distearyl sebacic acid amide, etc. Specific examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyl adipic acid amide, N,N'-dioleyl sebacic acid amide, etc. Specific examples of fatty acid ester amides include stearamide ethyl stearate, etc. Specific examples of aromatic bisamides include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, and N,N'-distearylisophthalic acid amide. The lubricant may be used alone or in combination of two or more types, preferably in combination of two or more types.

When a lubricant is present on the surface of the surface coating layer 6, the amount of the lubricant present is not particularly limited, and may be, for example, about 3 mg/m ² or more, preferably about 4 mg/m ² or more, or about 5 mg/m ² or more. The amount of the lubricant present on the surface of the surface coating layer 6 may be, for example, about 15 mg/m ² or less, preferably about 14 mg/m ² or less, or about 10 mg/m ² or less. The preferred range of the amount of the lubricant present on the surface of the surface coating layer 6 may be about 3 to 15 mg/m ² , about 3 to 14 mg/m ² , about 3 to 10 mg/m ² , about 4 to 15 mg/m ² , about 4 to 14 mg/m ² , about 4 to 10 mg/m ² , about 5 to 15 mg/m ² , about 5 to 14 mg/m ² , or about 5 to 10 mg/m ² .

The lubricant present on the surface of the surface coating layer 6 may be a lubricant exuded from the resin that constitutes the surface coating layer 6, or a lubricant applied to the surface of the surface coating layer 6.

The surface coating layer 6 contains a colorant, so that the exterior material for the electricity storage device can be colored. Known colorants such as pigments and dyes can be used as the colorant. Furthermore, only one type of colorant may be used, or two or more types may be mixed together.

The type of pigment is not particularly limited, and examples of organic pigments include azo, phthalocyanine, quinacridone, anthraquinone, dioxazine, indigothioindigo, perinone-perylene, isoindolenine, and benzimidazolone pigments, while examples of inorganic pigments include carbon black, titanium oxide, cadmium, lead, chromium oxide, and iron pigments, as well as finely powdered mica and fish scale foil.

Among colorants, carbon black is preferred in order to give the exterior material for an electricity storage device a black appearance. Also, from the viewpoint of dissipating heat generated by the electricity storage device, it is preferable to use mica.

The content of the colorant or pigment in the surface coating layer 6 is not particularly limited as long as the exterior material for the electricity storage device is colored, and may be, for example, about 5 to 60% by mass, and preferably about 10 to 40% by mass.

The thickness of the surface coating layer 6 is not particularly limited as long as it exhibits the above-mentioned functions of the surface coating layer 6, and may be, for example, about 0.5 to 10 μm, and preferably about 1 to 5 μm.

3. Manufacturing method of the exterior material for a power storage device The manufacturing method of the exterior material for a power storage device is not particularly limited as long as a laminate in which each layer included in the exterior material for a power storage device of the present invention is laminated can be obtained. That is, the manufacturing method of the exterior material for a power storage device of the first aspect of the present disclosure includes a step of obtaining a laminate in which at least a base layer, a metal foil layer, and a heat-sealable resin layer are laminated in order from the outside, and the maximum reflected light intensity A in the range of a light receiving angle of 0.0° to 90.0° is 50 or less for at least one surface of the metal foil layer, measured at every 0.1° of the light receiving angle under the condition of an incident light angle of 60° using a variable angle photometer. Further, the manufacturing method of the exterior material for an electric storage device of the second aspect of the present disclosure includes a step of obtaining a laminate in which, from the outside, at least a base layer, a metal foil layer, and a heat-sealable resin layer are laminated, and the maximum reflected light intensity B in the range of a light receiving angle of 45.0° to 75.0°, measured at every 0.1° of the light receiving angle under the condition of an incident light angle of 60° using a variable angle photometer, for at least one surface of the metal foil layer, is 300 or more. As described above, when the laminate constituting the exterior material for an electric storage device of the present disclosure does not include a base layer, the manufacturing method of the exterior material for an electric storage device of the present disclosure includes a step of obtaining a laminate in which, from the outside, at least a metal foil layer and a heat-sealable resin layer are laminated.

An example of a manufacturing method for the exterior material for a power storage device according to the present disclosure is as follows. First, a laminate (hereinafter sometimes referred to as "laminate A") is formed in which a base layer 1, an adhesive layer 2, and a metal foil layer 3 are laminated in this order. Specifically, laminate A can be formed by a dry lamination method in which the adhesive used to form the adhesive layer 2 is applied to the base layer 1 or to the metal foil layer 3, the surface of which has been chemically treated as necessary, by a coating method such as gravure coating or roll coating, and then dried, and the metal foil layer 3 or base layer 1 is laminated thereon, and the adhesive layer 2 is cured.

Next, the heat-sealable resin layer 4 is laminated on the metal foil layer 3 of the laminate A. When the heat-sealable resin layer 4 is directly laminated on the metal foil layer 3, the heat-sealable resin layer 4 may be laminated on the metal foil layer 3 of the laminate A by a method such as thermal lamination or extrusion lamination. When an adhesive layer 5 is provided between the metal foil layer 3 and the heat-sealable resin layer 4, the adhesive layer 5 and the heat-sealable resin layer 4 may be laminated, for example, by (1) extrusion lamination, (2) thermal lamination, (3) sandwich lamination, or (4) dry lamination. (1) Extrusion lamination includes, for example, a method of laminating the adhesive layer 5 and the heat-sealable resin layer 4 by extruding them onto the metal foil layer 3 of the laminate A (co-extrusion lamination, tandem lamination). Examples of the (2) thermal lamination method include a method of forming a laminate in which an adhesive layer 5 and a heat-sealable resin layer 4 are laminated separately, and laminating this on the metal foil layer 3 of the laminate A, or a method of forming a laminate in which an adhesive layer 5 is laminated on the metal foil layer 3 of the laminate A, and laminating this on the heat-sealable resin layer 4. Examples of the (3) sandwich lamination method include a method of laminating the laminate A and the heat-sealable resin layer 4 through the adhesive layer 5 while pouring a molten adhesive layer 5 between the metal foil layer 3 of the laminate A and the heat-sealable resin layer 4 previously formed into a sheet. Examples of the (4) dry lamination method include a method of coating the metal foil layer 3 of the laminate A with an adhesive for forming the adhesive layer 5, drying the adhesive, or baking the adhesive, and laminating the heat-sealable resin layer 4 previously formed into a sheet on the adhesive layer 5.

When the surface coating layer 6 is provided, the surface coating layer 6 is laminated on the surface of the base layer 1 opposite the metal foil layer 3. The surface coating layer 6 can be formed, for example, by applying the above-mentioned resin that forms the surface coating layer 6 to the surface of the base layer 1. The order of the step of laminating the metal foil layer 3 on the surface of the base layer 1 and the step of laminating the surface coating layer 6 on the surface of the base layer 1 is not particularly limited. For example, after the surface coating layer 6 is formed on the surface of the base layer 1, the metal foil layer 3 may be formed on the surface of the base layer 1 opposite the surface coating layer 6.

As described above, a laminate is formed which includes, in this order, the optional surface coating layer 6, the base layer 1, the optional adhesive layer 2, the metal foil layer 3, the optional adhesive layer 5, and the heat-sealable resin layer 4. In order to strengthen the adhesion of the optional adhesive layer 2 and adhesive layer 5, the laminate may be subjected to a heat treatment.

In the exterior material for power storage devices, each layer constituting the laminate may be subjected to a surface activation treatment such as corona treatment, blast treatment, oxidation treatment, or ozone treatment, as necessary, to improve its suitability for processing. For example, by subjecting the surface of the base layer 1 opposite the metal foil layer 3 to corona treatment, the suitability for printing ink on the surface of the base layer 1 can be improved.

The exterior material for an electricity storage device according to the present disclosure is used in a package for hermetically housing an electricity storage device element such as a positive electrode, a negative electrode, an electrolyte, etc. In other words, an electricity storage device element including at least a positive electrode, a negative electrode, and an electrolyte can be housed in a package formed from the exterior material for an electricity storage device according to the present disclosure to form an electricity storage device.

Specifically, an electricity storage device element having at least a positive electrode, a negative electrode, and an electrolyte is covered with the exterior material for an electricity storage device of the present disclosure in such a manner that a flange portion (a region where the heat-sealable resin layers contact each other) can be formed around the periphery of the electricity storage device element with metal terminals connected to each of the positive electrode and negative electrode protruding outward, and the heat-sealable resin layers of the flange portion are heat-sealed to provide an electricity storage device using the exterior material for an electricity storage device. When an electricity storage device element is housed in a package formed from the exterior material for an electricity storage device of the present disclosure, the package is formed so that the heat-sealable resin portion of the exterior material for an electricity storage device of the present disclosure faces inside (the surface in contact with the electricity storage device element). The heat-sealable resin layers of two electrical storage device exterior materials may be stacked facing each other, and the peripheral portions of the stacked electrical storage device exterior materials may be heat-sealed to form a package. Alternatively, as shown in the example of FIG. 5, one electrical storage device exterior material may be folded back and stacked, and the peripheral portions may be heat-sealed to form a package. When the materials are folded back and stacked, as shown in the example of FIG. 5, the sides other than the folded side may be heat-sealed to form a package by sealing on three sides, or the materials may be folded back and sealed on all four sides so that a flange portion can be formed. When the innermost and outermost layers of the electrical storage device exterior material are heat-sealable resin layers, the package may be formed by heat-sealing the innermost heat-sealable resin layer and the outermost heat-sealable resin layer.

The power storage device element may be sealed by a lid in addition to the exterior material for the power storage device. That is, the exterior material for the power storage device and the lid constitute an exterior body (exterior body for the power storage device) that seals the power storage device element. For example, the power storage device element may be housed inside the exterior material for the power storage device that is configured in a cylindrical shape, and the opening may be closed by the lid. In another example, the power storage device element connected to the lid may be housed inside the exterior material for the power storage device that is configured in a cylindrical shape so that an opening is formed, and the opening may be closed by the lid. The lid and the exterior material for the power storage device are preferably joined by any means. From the viewpoint of reducing the dead space between the power storage device element and the exterior material for the power storage device in order to improve the volumetric energy density of the power storage device, the exterior material for the power storage device is preferably wrapped around the power storage device element and the lid.

The lid body can be formed, for example, from a resin molded product, a metal molded product, an exterior material for an electricity storage device, or a combination of these. In this disclosure, when the lid body is expressed as a resin molded product, this does not include an embodiment in which the lid body is composed only of a film as defined by JIS K6900-1994 [Plastics terminology]. When the lid body is a metal molded product, the lid body also functions as a metal terminal, so the metal terminal can be omitted. The lid body may be composed of a resin material and a conductive material.

In addition, a recess for accommodating an electricity storage device element may be formed in the exterior material for the electricity storage device by deep drawing or stretch molding. As in the example shown in FIG. 5, a recess may be provided in one exterior material for the electricity storage device and no recess may be provided in the other exterior material for the electricity storage device, or a recess may be provided in the other exterior material for the electricity storage device.

The exterior material for an electricity storage device of the present disclosure can be suitably used for electricity storage devices such as batteries (including condensers, capacitors, etc.). The exterior material for an electricity storage device of the present disclosure may be used for either a primary battery or a secondary battery, but is preferably used for a secondary battery. The type of secondary battery to which the exterior material for an electricity storage device of the present disclosure is applied is not particularly limited, and examples thereof include lithium ion batteries, lithium ion polymer batteries, all-solid batteries, semi-solid batteries, quasi-solid batteries, polymer batteries, all-resin batteries, lead-acid batteries, nickel-hydrogen batteries, nickel-cadmium batteries, nickel-iron batteries, nickel-zinc batteries, silver oxide-zinc batteries, metal-air batteries, polyvalent cation batteries, condensers, capacitors, etc. Among these secondary batteries, the exterior material for an electricity storage device of the present disclosure is suitably applied to lithium ion batteries and lithium ion polymer batteries.

The present disclosure will be explained in detail below with examples and comparative examples. However, the present disclosure is not limited to the examples.

<Production of exterior materials for power storage devices>
Example 1
A stretched nylon film (thickness 25 μm) was prepared as the substrate layer. In addition, each aluminum alloy foil A (thickness 40 μm) having the surface properties and composition described in Table 1 was prepared as the metal foil layer. The matte side of the aluminum alloy foil was the substrate layer side, and the glossy side was the heat-fusible resin layer side. Details of each aluminum alloy foil used in the examples and comparative examples will be described later. Using a two-liquid urethane adhesive (polyol compound and aromatic isocyanate compound), the stretched nylon film side of the aluminum alloy foil and the substrate layer were laminated by dry lamination so that the thickness of the adhesive layer after curing was 3 μm, and then aging treatment was performed to produce a substrate layer/adhesive layer/metal foil layer laminate. Both sides of the aluminum alloy foil were subjected to chemical conversion treatment. The chemical conversion treatment of the aluminum alloy foil was performed by applying a treatment solution consisting of a phenolic resin, a chromium fluoride compound, and phosphoric acid to both sides of the aluminum alloy foil by roll coating so that the amount of chromium applied was 10 mg/ ^m2 (dry mass), and baking the solution.

Next, maleic anhydride modified polypropylene as an adhesive layer (thickness 22.5 μm) and random polypropylene as a heat-sealable resin layer (thickness 22.5 μm) were co-extruded onto the metal foil layer of each laminate obtained above, thereby laminating the adhesive layer/heat-sealable resin layer on top of the metal foil layer, thereby obtaining an exterior material for an electricity storage device in which the substrate layer/adhesive layer/metal foil layer/adhesive layer/heat-sealable resin layer were laminated in this order.

Example 2
An exterior material for an electricity storage device was obtained in the same manner as in Example 1, except that aluminum alloy foil B (having a thickness of 40 μm) described below was used instead of aluminum alloy foil A.

Example 3
An exterior material for an electricity storage device was obtained in the same manner as in Example 1, except that aluminum alloy foil C (having a thickness of 40 μm) described below was used instead of aluminum alloy foil A.

Comparative Example 1
An exterior material for an electricity storage device was obtained in the same manner as in Example 1, except that aluminum alloy foil E (having a thickness of 40 μm) described below was used instead of aluminum alloy foil A.

<Aluminum alloy foil>
Details of the aluminum alloy foils used as the metal foil layers in the examples and comparative examples are as follows.
Aluminum alloy foil A (used in Example 1): Aluminum alloy foil having the composition of JIS A8021 and the composition in Table 1 was adjusted to have the surface properties in Table 1 by setting the rolling speed and the tensile tension during rolling under predetermined conditions. Aluminum alloy foil B (used in Example 2): Aluminum alloy foil having the composition of JIS A8021 and the composition in Table 1 (Si content is increased compared to Aluminum Alloy Foil A) was adjusted to have the surface properties in Table 1 by setting the rolling speed and the tensile tension during rolling under predetermined conditions. A Aluminum alloy foil C (used in Example 3): Aluminum alloy foil having the composition of JIS A8021 and the composition in Table 1 (Si content is further increased compared to Aluminum Alloy Foil B) was adjusted to have the surface properties in Table 1 by setting the rolling speed and tensile tension during rolling under predetermined conditions. Aluminum alloy foil E (used in Comparative Example 1): Aluminum alloy foil having the composition of JIS A8006 and the composition in Table 1 was adjusted to have the surface properties in Table 1 by setting the rolling speed and tensile tension during rolling under predetermined conditions.

<Surface properties of metal foil layer (goniophotometer)>
The maximum reflected light intensity and maximum tilt were measured using a goniophotometer for the matte surface and the glossy surface of each of the aluminum alloy foils of the packaging materials for an electricity storage device of the Examples and Comparative Examples.

Each aluminum alloy foil was removed from each exterior material for power storage devices using the following procedure and used as the measurement subject. The base layer of the exterior material for power storage devices was manually peeled off to leave a laminate of aluminum alloy foil, adhesive layer, and heat-sealable resin layer. This laminate was then immersed in orthodichlorobenzene under the following conditions to remove the adhesive layer and heat-sealable resin layer from the aluminum alloy foil, and the surface of the aluminum alloy foil was washed multiple times with ethanol and left to dry, and the resulting aluminum alloy foil was used as the measurement subject.

Next, the maximum reflected light intensity and maximum tilt were measured for the matte and glossy sides of each aluminum alloy foil using a goniophotometer under the following measurement conditions. The results are shown in Table 1.

(Measurement conditions for standard black glass using a variable angle photometer)
Measurement target: Black glass reference plate BK-7 (black glass reference plate, refractive index 1.518) manufactured by Murakami Color Research Laboratory Co., Ltd.
Equipment: Variable angle photometer GP-200 manufactured by Murakami Color Research Laboratory Co., Ltd.
Incident angle (IA): 60°
Receiving angle: +50° to +70°, measured in 0.1° increments. Facing angle (FA): 0°
Incident light aperture (VS1): 3 (10.5 mm)
Aperture (VS3): 4 (9.1 mm)
SENSITIVITY: 950
HIGH VOLT.: 539 (adjusted so that the reflection intensity of black glass (black glass reference plate) is 85)
Neutral density filters: 1% filter, 50% filter

(Measurement conditions for the variable angle photometer (matte surface))
Equipment: Variable angle photometer GP-200 manufactured by Murakami Color Research Laboratory Co., Ltd.
Sample fixation: The sample was fixed on a suction sample stage. Incident angle (IA): 60°
Receiving angle: 0 to +90°, measured in 0.1° increments. Facing angle (FA): 0°
Incident light aperture (VS1): 3 (10.5 mm)
Aperture (VS3): 4 (9.1 mm)
SENSITIVITY: 950
HIGH VOLT.: 539 (Use a value adjusted so that the reflection intensity of standard black plate glass (black glass reference plate BK-7 refractive index 1.518) is 85)
Neutral density filter: 1% filter Incident direction: Parallel to the rolling direction of the aluminum alloy foil

(Measurement conditions for the variable angle photometer (glossy surface))
Equipment: Variable angle photometer GP-200 manufactured by Murakami Color Research Laboratory Co., Ltd.
Sample fixation: The sample was fixed on a suction sample stage.
Incident angle (IA): 60°
Receiving angle: +45° to +75°, measured in 0.1° increments. Facing angle (FA): 0°
Incident light aperture (VS1): 3 (10.5 mm)
Aperture (VS3): 4 (9.1 mm)
SENSITIVITY: 950
HIGH VOLT.: 539 (Used a value adjusted so that the reflection intensity of standard black plate glass (black glass reference plate BK-7 refractive index 1.518) is 85)
Neutral density filters: 1% filter, 10% filter, 50% filter Incident direction: Parallel to the rolling direction of the aluminum alloy foil

<Evaluation of moldability>
Each electrical storage device exterior material was cut into a square with a length (MD) of 170 mm and a width (TD) of 170 mm to prepare a test sample. The MD of the electrical storage device exterior material corresponds to the rolling direction (RD) of the aluminum alloy foil, and the TD of the electrical storage device exterior material corresponds to the TD of the aluminum alloy foil. This sample was placed in a 25°C environment in a rectangular molding die (female die, the surface has a maximum height roughness (nominal value of Rz) of 3.2 μm as specified in Table 2 of the surface roughness standard piece for comparison in JIS B 0659-1:2002 Annex 1 (Reference), corner R2.0 mm, ridgeline R1.0 mm) with an aperture of 100 mm (MD) x 110 mm (TD) and a corresponding molding die (male die, the surface of the ridgeline portion has a maximum height roughness (nominal value of Rz) of 1.6 μm as specified in Table 2 of the surface roughness standard piece for comparison in JIS B 0659-1:2002 Annex 1 (Reference), corner R2.0 mm, ridgeline R1.0 mm). The maximum height roughness (nominal value of Rz) specified in Table 2 of the comparative surface roughness standard piece is 3.2 μm. Using a corner R2.0 mm, ridge R1.0 mm), the molding depth was changed in 0.5 mm increments from the molding depth of 0.5 mm at a pressing pressure (surface pressure) of 0.5 MPa, and cold molding (one-stage drawing molding) was performed on 10 samples each. At this time, the above test sample was placed on the female mold so that the heat-fusible resin layer side was located on the male mold side and molding was performed. In addition, the clearance between the male mold and the female mold was set to 0.3 mm. The sample after cold molding was irradiated with light from a penlight in a dark room to confirm whether pinholes or cracks were generated in the aluminum alloy foil due to light transmission. For the sample after cold molding, the deepest molding depth at which pinholes and cracks did not occur in the exterior material for power storage devices in all 10 samples was determined as the limit molding depth of the sample. The evaluation criteria for the formability of the exterior material for an electricity storage device were as follows, and the results are shown in Table 1.

(Moldability Evaluation Criteria)
A+: The limit forming depth is 13.5 mm or more.
A: The limit forming depth is 11.0 mm or more and 13.0 mm or less.
B: The limit forming depth is 8.5 mm or more and 10.5 mm or less.
C: The limit forming depth is 6.0 mm or more and 8.0 mm or less.
D: The limit forming depth is 5.5 mm or less.

Example 4
The substrate layer (stretched nylon film (thickness 25 μm)) was replaced with a substrate layer (stretched nylon film (thickness 20 μm)), the adhesive layer (maleic anhydride-modified polypropylene (thickness 22.5 μm)) was replaced with an adhesive layer (maleic anhydride-modified polypropylene (thickness 20 μm)), and the heat-sealable resin layer (random polypropylene (thickness 22.5 μm)) was replaced with a heat-sealable resin layer (random polypropylene (thickness 15 μm)). Except for this, a substrate layer (stretched nylon film (thickness 20 m)) / adhesive layer (thickness 3 μm) / metal foil layer (aluminum alloy foil B (thickness is 40 μm)) / adhesive layer (maleic anhydride-modified polypropylene (thickness is 20 μm)) / heat-sealable resin layer (random polypropylene (thickness 15 μm)) was laminated in the same manner as in Example 2 to obtain an exterior material for a storage device. In Example 4, two types of lubricants, a saturated fatty acid amide (behenic acid amide) and an unsaturated fatty acid amide (erucic acid amide), were used in combination as the lubricant contained in the heat-sealable resin layer. The exterior material for an electricity storage device of Example 4 was evaluated as having the same moldability as Example 2.

Example 5
Instead of the base layer (stretched nylon film (thickness 25 μm)), a base layer (a laminated film in which a polyethylene terephthalate film (thickness 12 μm) and a stretched nylon film (thickness 15 μm) are laminated with an adhesive layer (thickness 3 μm)), instead of the adhesive layer (maleic anhydride modified polypropylene (thickness 22.5 μm)), an adhesive layer (maleic anhydride modified polypropylene (thickness 40 μm)), instead of the heat-sealing resin layer (random polypropylene (thickness 22.5 μm)), Except for using the laminated film (thickness 40 μm) of the laminated film, the laminated film was a laminated film of a polyethylene terephthalate film (thickness 12 μm) and a stretched nylon film (thickness 15 μm) with an adhesive layer (thickness 3 μm))/adhesive layer (thickness 3 μm)/metal foil layer (aluminum alloy foil B (thickness 40 μm))/adhesive layer (maleic anhydride modified polypropylene (thickness 40 μm))/thermal adhesive resin layer (random polypropylene (thickness 40 μm)). In the production of the electrical storage device exterior material, the stretched nylon film side of the base material layer was bonded to the metal foil layer via the adhesive layer. In addition, in Example 5, two types of lubricants, saturated fatty acid amide (behenic acid amide) and unsaturated fatty acid amide (erucic acid amide), were used in combination as the lubricant contained in the thermal adhesive resin layer. The electrical storage device exterior material of Example 5 had the same moldability evaluation as Example 1.

As described above, the present disclosure provides the following aspects of the invention.
Item 1. The laminate includes, in order from the outside, at least an optional base material layer, a metal foil layer, and a heat-sealable resin layer;
The exterior material for an electricity storage device has a maximum reflected light intensity A of 50 or less in a light receiving angle range of 0.0° or more and 90.0° or less, measured for at least one surface of the metal foil layer at every 0.1° of light receiving angle using a goniophotometer under a condition of an incident light angle of 60°.
Item 2. The exterior material for an electricity storage device according to Item 1, wherein the surface of the metal foil layer is a matte surface.
Item 3. The laminate includes, in order from the outside, at least an optional base material layer, a metal foil layer, and a heat-sealable resin layer;
The exterior material for an electricity storage device has a maximum reflected light intensity B of 300 or more in a light receiving angle range of 45.0° or more and 75.0° or less, measured for at least one surface of the metal foil layer at every 0.1° of light receiving angle using a variable angle photometer under a condition of an incident light angle of 60°.
Item 4. The exterior material for an electricity storage device according to Item 3, wherein the surface of the metal foil layer is a glossy surface.
Item 5. The exterior material for an electricity storage device according to any one of Items 1 and 2, wherein a maximum slope C of at least one surface of the metal foil layer is 10.0 or less in a light-receiving angle range of 0.0° to 90.0°, as measured at every 0.1° of light-receiving angle using a goniophotometer under a condition of an incident light angle of 60°.
Item 6. The exterior material for an electricity storage device according to any one of Items 3 and 4, wherein a maximum slope D of at least one surface of the metal foil layer is 200 or more within a light-receiving angle range of 45.0° to 75.0°, as measured at every 0.1° of the light-receiving angle using a goniophotometer under a condition of an incident light angle of 60°.
Item 7. The exterior material for an electricity storage device according to any one of Items 1 to 6, wherein the metal foil layer includes at least one of an aluminum alloy foil and a stainless steel foil.
Item 8. The exterior material for an electricity storage device according to any one of Items 1 to 7, further comprising an adhesive layer between the base material layer and the metal foil layer.
Item 9. The packaging material for an electricity storage device according to any one of Items 1 to 8, further comprising an adhesive layer between the metal foil layer and the heat-fusible resin layer.
Item 10. The exterior material for a storage battery device according to any one of Items 1 to 9, wherein the base material layer includes a laminate of a polyester film and a polyamide film, a laminate of a polyester film and a polyester film, or a laminate of a polyamide film and a polyamide film.
Item 11. The exterior material for an electricity storage device according to any one of Items 1 to 10, wherein the laminate has a thickness of 155 μm or less.
Item 12. The exterior material for an electricity storage device according to any one of Items 1 to 11, wherein the laminate has a thickness of 155 μm or more and 190 μm or less.
Item 13. Or, the exterior material for an electricity storage device according to any one of Items 1 to 12, wherein the laminate has a thickness of 190 μm or more and 300 μm or less.
Item 14. The exterior material for an electricity storage device according to any one of Items 1 to 13, wherein two or more types of lubricants are present on at least one of a surface and an interior of the base layer.
Item 15. The exterior material for a storage battery device according to any one of Items 1 to 14, wherein at least two selected from the group consisting of saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides are present on at least one of the surface and the interior of the base layer.
Item 16. The exterior material for an electricity storage device according to any one of Items 1 to 15, wherein the base material layer has a thickness of 35 μm or less.
Item 17. The exterior material for an electricity storage device according to any one of Items 1 to 16, wherein the base material layer has a thickness of 35 μm or more and 100 μm or less.
Item 18. The exterior material for an electricity storage device according to any one of Items 1 to 17, wherein the metal foil layer has a thickness of 50 μm or less.
Item 19. The exterior material for an electricity storage device according to any one of Items 1 to 18, wherein the metal foil layer has a thickness of 50 μm or more and 200 μm or less.
Item 20. The exterior packaging material for an electricity storage device according to any one of Items 1 to 19, wherein the heat-sealable resin layer is composed of a resin containing a polyolefin skeleton.
Item 21. The exterior material for a storage battery device according to any one of Items 1 to 20, wherein the heat-sealable resin layer contains at least one selected from the group consisting of polyolefins, cyclic polyolefins, acid-modified polyolefins, and acid-modified cyclic polyolefins.
Item 22. The exterior packaging material for an electricity storage device according to any one of Items 1 to 21, wherein the heat-fusible resin layer is formed of a blend polymer in which two or more types of resins are combined.
Item 23. The exterior packaging material for an electricity storage device according to any one of Items 1 to 22, wherein the heat-sealable resin layer is formed of two or more layers of the same or different resins.
Item 24. The exterior packaging material for an electricity storage device according to any one of Items 1 to 23, wherein two or more types of lubricants are present on at least one of a surface and an interior of the heat-sealable resin layer.
Item 25. The exterior material for a storage battery device according to any one of Items 1 to 24, wherein at least two selected from the group consisting of saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides are present on at least one of the surface and the interior of the heat-sealable resin layer.
Item 26. The electrical storage device packaging material according to any one of Items 1 to 25, wherein the electrical storage device packaging material is colored.
Item 27. An adhesive layer is further provided between the base layer and the metal foil layer,
Item 27. The exterior material for a storage battery device according to any one of items 1 to 26, wherein the adhesive layer contains a colorant.
Item 28. The exterior material for an electricity storage device according to any one of Items 1 to 27, further comprising a colored layer between the base layer and the metal foil layer.
Item 29. The exterior material for an electricity storage device according to any one of Items 1 to 28, further comprising a surface coating layer on the opposite side of the base material layer to the metal foil layer side.
Item 30. The exterior material for a storage battery device according to Item 29, wherein the surface coating layer contains a colorant.
Item 31. The exterior material for an electricity storage device according to Item 29, wherein the surface coating layer contains titanium oxide.
Item 32. The exterior material for an electricity storage device according to Item 29, wherein the surface coating layer contains silica.
Item 33. The exterior material for a power storage device according to Item 29, wherein the surface coating layer contains at least one selected from the group consisting of talc, silica, graphite, kaolin, montmorillonite, mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, neodymium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, alumina, carbon black, carbon nanotubes, high melting point nylon, acrylate resin, crosslinked acrylic, crosslinked styrene, crosslinked polyethylene, benzoguanamine, gold, aluminum, copper, and nickel.
Item 34. The method includes a step of obtaining a laminate in which at least an arbitrary base material layer, a metal foil layer, and a heat-sealable resin layer are laminated in this order from the outside,
a maximum reflected light intensity A of 50 or less in a light-receiving angle range of 0.0° or more and 90.0° or less, measured for at least one surface of the metal foil layer at every 0.1° light-receiving angle using a goniophotometer under a condition of an incident light angle of 60°.
Item 35. The method includes a step of obtaining a laminate in which at least an arbitrary base material layer, a metal foil layer, and a heat-sealable resin layer are laminated in this order from the outside,
a maximum reflected light intensity B of 300 or more at a light-receiving angle range of 45.0° or more and 75.0° or less, measured at every 0.1° of a light-receiving angle using a goniophotometer under a condition of an incident light angle of 60°, for at least one surface of the metal foil layer.
Item 36. An adhesive layer is further provided between the metal foil layer and the heat-sealable resin layer,
Item 36. The method for producing an exterior material for a storage battery device according to item 34 or 35, wherein the adhesive layer and the heat-fusible resin layer are laminated by (1) an extrusion lamination method, (2) a thermal lamination method, (3) a sandwich lamination method, or (4) a dry lamination method.
Item 37. The method for producing an exterior material for an electricity storage device according to Item 36, wherein the heat-sealable resin layer is formed of two or more layers of the same or different resins.
Item 38. An electricity storage device, comprising an electricity storage device element including at least a positive electrode, a negative electrode, and an electrolyte, housed in a package formed from the exterior material for an electricity storage device according to any one of Items 1 to 33.

1 Base material layer 2 Adhesive layer 3 Metal foil layer 4 Heat-fusible resin layer 5 Adhesive layer 6 Surface coating layer 10 Exterior material for power storage device

Claims

The laminate includes, in order from the outside, at least a base layer, a metal foil layer, and a heat-sealable resin layer.
The exterior material for an electricity storage device has a maximum reflected light intensity A of 50 or less in a light receiving angle range of 0.0° or more and 90.0° or less, measured for at least one surface of the metal foil layer at every 0.1° of light receiving angle using a goniophotometer under a condition of an incident light angle of 60°.
The exterior material for an electricity storage device according to claim 1, wherein the surface of the metal foil layer is a matte surface.
The laminate includes, in order from the outside, at least a base layer, a metal foil layer, and a heat-sealable resin layer.
The exterior material for an electricity storage device has a maximum reflected light intensity B of 300 or more in a light receiving angle range of 45.0° or more and 75.0° or less, measured for at least one surface of the metal foil layer at every 0.1° of light receiving angle using a variable angle photometer under a condition of an incident light angle of 60°.
The exterior material for an electricity storage device according to claim 3, wherein the surface of the metal foil layer is glossy.
The exterior material for a storage battery device according to claim 1 or 2, wherein the maximum slope C of at least one surface of the metal foil layer is 10.0 or less in the light receiving angle range of 0.0° to 90.0°, measured at every 0.1° of light receiving angle using a goniophotometer under the condition of an incident light angle of 60°.
The exterior material for a storage battery device according to claim 3 or 4, wherein the maximum slope D measured for at least one surface of the metal foil layer at a light receiving angle of 45.0° to 75.0° at intervals of 0.1° using a goniophotometer under the condition of an incident light angle of 60° is 200 or more.
The exterior material for an electricity storage device according to any one of claims 1 to 4, wherein the metal foil layer includes at least one of an aluminum alloy foil and a stainless steel foil.
The exterior material for an electricity storage device according to any one of claims 1 to 4, further comprising an adhesive layer between the base layer and the metal foil layer.
The exterior material for an electricity storage device according to any one of claims 1 to 4, further comprising an adhesive layer between the metal foil layer and the heat-sealable resin layer.
The exterior material for an electricity storage device according to any one of claims 1 to 4, wherein the base layer includes a laminate of a polyester film and a polyamide film, a laminate of a polyester film and a polyester film, or a laminate of a polyamide film and a polyamide film.
The exterior material for an electricity storage device according to any one of claims 1 to 4, wherein the thickness of the laminate is 155 μm or less.
The exterior material for an electricity storage device according to any one of claims 1 to 4, wherein the thickness of the laminate is 155 μm or more and 190 μm or less.
Or, the exterior material for an electricity storage device according to any one of claims 1 to 4, wherein the thickness of the laminate is 190 μm or more and 300 μm or less.
The exterior material for an electricity storage device according to any one of claims 1 to 4, wherein two or more types of lubricants are present on at least one of the surface and the interior of the base layer.
The exterior material for a storage battery device according to any one of claims 1 to 4, wherein at least two selected from the group consisting of saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides are present on at least one of the surface and interior of the base layer.
The exterior material for an electricity storage device according to any one of claims 1 to 4, wherein the thickness of the substrate layer is 35 μm or less.
The exterior material for an electricity storage device according to any one of claims 1 to 4, wherein the thickness of the substrate layer is 35 μm or more and 100 μm or less.
The exterior material for an electricity storage device according to any one of claims 1 to 4, wherein the thickness of the metal foil layer is 50 μm or less.
The exterior material for an electricity storage device according to any one of claims 1 to 4, wherein the thickness of the metal foil layer is 50 μm or more and 200 μm or less.
The exterior material for an electricity storage device according to any one of claims 1 to 4, wherein the heat-sealable resin layer is composed of a resin containing a polyolefin skeleton.
The exterior material for an electricity storage device according to any one of claims 1 to 4, wherein the heat-sealable resin layer contains at least one selected from the group consisting of polyolefins, cyclic polyolefins, acid-modified polyolefins, and acid-modified cyclic polyolefins.
The exterior material for an electricity storage device according to any one of claims 1 to 4, wherein the heat-sealable resin layer is formed from a blend polymer that combines two or more types of resin.
The exterior material for an electricity storage device according to any one of claims 1 to 4, wherein the heat-sealable resin layer is formed of two or more layers of the same or different resins.
The exterior material for an electricity storage device according to any one of claims 1 to 4, wherein at least two types of lubricant are present on at least one of the surface and the interior of the heat-sealable resin layer.
The exterior material for a storage battery device according to any one of claims 1 to 4, wherein at least two selected from the group consisting of saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides are present on at least one of the surface and interior of the heat-sealable resin layer.
The electrical storage device exterior material according to any one of claims 1 to 4, wherein the electrical storage device exterior material is colored.
An adhesive layer is further provided between the base layer and the metal foil layer,
The exterior material for an electricity storage device according to any one of claims 1 to 4, wherein the adhesive layer contains a colorant.
The exterior material for an electricity storage device according to any one of claims 1 to 4, further comprising a colored layer between the base layer and the metal foil layer.
The exterior material for an electricity storage device according to any one of claims 1 to 4, further comprising a surface coating layer on the side of the base layer opposite the metal foil layer.
The exterior material for a storage battery device according to claim 29, wherein the surface coating layer contains a colorant.
The exterior material for an electricity storage device according to claim 29, wherein the surface coating layer contains titanium oxide.
The exterior material for an electricity storage device according to claim 29, wherein the surface coating layer contains silica.
The exterior material for an electricity storage device according to claim 29, wherein the surface coating layer contains at least one selected from the group consisting of talc, silica, graphite, kaolin, montmorillonite, mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, neodymium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, alumina, carbon black, carbon nanotubes, high melting point nylon, acrylate resin, cross-linked acrylic, cross-linked styrene, cross-linked polyethylene, benzoguanamine, gold, aluminum, copper, and nickel.
The method includes a step of obtaining a laminate in which at least a base layer, a metal foil layer, and a heat-fusible resin layer are laminated in this order from the outside,
a maximum reflected light intensity A of 50 or less in a light-receiving angle range of 0.0° or more and 90.0° or less, measured for at least one surface of the metal foil layer at every 0.1° light-receiving angle using a goniophotometer under a condition of an incident light angle of 60°.
The method includes a step of obtaining a laminate in which at least a base layer, a metal foil layer, and a heat-fusible resin layer are laminated in this order from the outside,
a maximum reflected light intensity B of 300 or more at a light-receiving angle range of 45.0° or more and 75.0° or less, measured at every 0.1° of a light-receiving angle using a goniophotometer under a condition of an incident light angle of 60°, for at least one surface of the metal foil layer.
An adhesive layer is further provided between the metal foil layer and the heat-sealable resin layer,
The method for producing an exterior material for an electricity storage device according to claim 34 or 35, wherein the adhesive layer and the heat-sealable resin layer are laminated by (1) an extrusion lamination method, (2) a thermal lamination method, (3) a sandwich lamination method, or (4) a dry lamination method.
The method for producing an exterior material for an electrical storage device according to claim 36, wherein the heat-sealable resin layer is formed of two or more layers of the same or different resins.
An electricity storage device in which an electricity storage device element having at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed from the exterior material for an electricity storage device according to any one of claims 1 to 4.