JP7225826B2 - Power storage device, exterior member for power storage device, power storage device assembly, electric vehicle, and method for manufacturing power storage device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electric storage device mounted on an electric vehicle and a manufacturing method thereof. The present invention also relates to an exterior member for an electricity storage device, which is used for the electricity storage device. The present invention also relates to an electricity storage device assembly using the electricity storage device and an electric vehicle.

In recent years, an electric vehicle in which a motor supplies at least part of the driving force has been attracting attention from the viewpoint of environmental measures, resource saving, and the like. Electric vehicles include electric vehicles (EV), hybrid vehicles (HEV), plug-in hybrid vehicles (PHEV), and the like. An electric vehicle uses only a motor as a power source, and a hybrid vehicle and a plug-in hybrid vehicle use a motor and an engine as power sources.

A conventional power storage device mounted on an electric vehicle is disclosed in Patent Document 1. This electricity storage device is composed of a thin secondary battery having a rectangular shape in a plan view and having a battery element covered by an exterior member. In the battery element, a positive electrode plate and a negative electrode plate are arranged to face each other with a separator interposed therebetween, and an electrolyte is arranged between the positive electrode plate and the negative electrode plate. The exterior member encloses the battery element by heat-sealing two laminates having metal foils with a heat-sealable resin layer. At this time, the terminals connected to the positive electrode plate and the negative electrode plate respectively protrude from the exterior member.

The power storage devices are stacked in the thickness direction and arranged side by side in the lateral direction of a rectangular shape in plan view to form an assembled battery composed of a plurality of power storage devices. Also, the assembled batteries are stacked in the thickness direction of the power storage device, and a composite assembled battery composed of a plurality of assembled batteries is installed under the floor of the electric vehicle.

Japanese Patent No. 3719235 (pages 4 to 11, Fig. 7)

However, according to the conventional power storage device, the weight of the upper power storage device is added to the lower power storage device because the power storage device is stacked in the height direction when mounted on a vehicle. As a result, the exterior member made of the laminated body is deformed, and if the load is increased due to the vibration of the vehicle or the like, the exterior member may be damaged. Therefore, there is a problem that the reliability of the electric storage device and the electric vehicle is lowered.

An object of the present invention is to provide an electricity storage device, an electricity storage device assembly, and an electric vehicle that can improve reliability. Another object of the present invention is to provide an exterior member for an electricity storage device used in an electricity storage device capable of improving reliability, and a method for manufacturing the electricity storage device.

In order to achieve the above object, the present invention encloses a power storage element in an exterior member comprising a laminate comprising at least a substrate layer, a barrier layer, and a heat-fusible resin layer in this order, and drives an electric vehicle. In the electricity storage device mounted as a power source, the exterior member has a peripheral edge seal portion and a storage portion formed at a predetermined depth from an inner edge of the peripheral edge seal portion to store the storage element, and the storage portion A first direction orthogonal to the depth direction of the storage space and the depth direction of the storage space is arranged in the front-rear direction or the left-right direction of the electric vehicle, and a second direction orthogonal to the depth direction of the storage space and the first direction The direction is arranged in the height direction of the electric vehicle,
At least one surface of the barrier layer is provided with a corrosion-resistant film, and when the corrosion-resistant film is analyzed using time-of-flight secondary ion mass spectrometry, the peak intensity P _CePO4 derived ^from _CePO4- The ratio P _PO3/CePO4 of the peak intensity P _{PO3 derived from PO 3 −} ^is in the range of 80 to 120, or the ratio _P PO2/ _CePO4 of the peak intensity P _PO2 derived from PO ₂ ⁻ to the peak intensity _{P CePO4} is It is characterized by being within the range of 90-150.

Further, according to the present invention, in the electricity storage device having the configuration described above, the length of the storage portion in the first direction is longer than the length in the second direction.

Further, according to the present invention, in the electricity storage device having the above configuration, the length of the storage portion in the first direction is 2 to 30 times the length in the second direction.

Further, according to the present invention, in the electricity storage device having the above configuration, the peripheral edge seal portion extending in the first direction is folded to be overlapped on the peripheral wall of the storage portion.

Further, according to the present invention, in the electricity storage device having the above configuration, the flow direction of the exterior member is orthogonal to the first direction.

Further, according to the present invention, in the electric storage device configured as described above, the electric storage element has a first electrode terminal and a second electrode terminal, and the first electrode terminal and the second electrode terminal extend in the second direction. It is characterized by protruding from

Further, according to the present invention, in the electricity storage device having the above configuration, the first electrode terminal and the second electrode terminal respectively protrude from the peripheral edge seal portion facing in the first direction.

Further, according to the present invention, in the electricity storage device having the above structure, the corrosion-resistant film is provided on the surface of the barrier layer on the heat-fusible resin layer side.

Further, according to the present invention, in the electricity storage device having the above structure, the corrosion-resistant film and the heat-fusible resin layer are laminated via an adhesive layer.

Further, according to the present invention, in the electricity storage device having the above structure, the resin forming the adhesive layer has a polyolefin skeleton.

Further, according to the present invention, in the electricity storage device having the above configuration, the adhesive layer contains an acid-modified polyolefin.

Further, according to the present invention, in the electricity storage device having the above structure, the acid-modified polyolefin contained in the adhesive layer is maleic anhydride-modified polypropylene, and the heat-fusible resin layer contains polypropylene.

Further, according to the present invention, in the electricity storage device having the above structure, a peak derived from maleic anhydride is detected when the adhesive layer is analyzed by infrared spectroscopy.

Further, according to the present invention, in the electricity storage device having the above configuration, the adhesive layer is 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 a compound having an epoxy group. It is characterized by being a cured product.

Further, according to the present invention, in the electricity storage device having the above configuration, the adhesive layer contains a curing agent having at least one selected from the group consisting of oxygen atoms, heterocycles, C═N bonds, and C—O—C bonds. It is characterized by being a cured product of a resin composition.

Further, according to the present invention, in the electricity storage device having the above structure, the adhesive layer contains at least one selected from the group consisting of urethane resin, ester resin, and epoxy resin.

Further, according to the present invention, in the electricity storage device having the above structure, the barrier layer is made of aluminum foil.

Further, according to the present invention, in the electricity storage device having the above structure, the resin forming the heat-fusible resin layer contains a polyolefin skeleton.

Further, the present invention provides an electricity storage device assembly in which a plurality of electricity storage devices having the above configurations are arranged side by side in the depth direction of the storage portion and housed in an exterior container, and which is mounted on an electric vehicle. It is characterized in that the length in the direction in which it is provided is longer than the length in the second direction.

Further, an electric vehicle according to the present invention includes an electricity storage device assembly configured as described above, a drive motor to which power is supplied from the electricity storage device assembly, and wheels driven by the drive motor, wherein the electricity storage device assembly is a vehicle body. It is characterized by being arranged in one step in the height direction at the bottom.

Further, the present invention provides an exterior member for an electricity storage device that encloses an electricity storage element of an electricity storage device mounted as a drive source in an electric vehicle, wherein at least a base layer, a barrier layer, and a heat-fusible resin layer are arranged in this order. a storage portion formed to a predetermined depth by opening an opening on one surface to store the power storage element; and a flange portion that is heat-sealed, and the length of the storage portion in a predetermined first direction within a plane perpendicular to the depth direction of the storage portion is greater than the length in a second direction perpendicular to the first direction. is large, the flow direction of the laminate is orthogonal to the first direction,
At least one surface of the barrier layer is provided with a corrosion-resistant film, and when the corrosion-resistant film is analyzed using time-of-flight secondary ion mass spectrometry, the peak intensity P _CePO4 derived ^from _CePO4- The ratio P _PO3/CePO4 of the peak intensity P _{PO3 derived from PO 3 − is} in the range of 80 to 120, or the ratio P PO2/ _CePO4 of the peak intensity P _PO2 derived from PO ₂ ⁻ to ^the peak intensity _{P CePO4} is It is characterized by being within the range of 90-150.

Further, according to the present invention, in the power storage device exterior member having the above configuration, the length of the storage portion in the first direction is 2 to 30 times the length in the second direction.

The present invention also provides a method for manufacturing an electric storage device to be mounted as a drive source in an electric vehicle, in which a storage section is provided by a laminate comprising at least a substrate layer, a barrier layer, and a heat-fusible resin layer in this order. and a step of storing the electric storage element in the storage portion and packaging it with the exterior member. The direction is arranged in the front-rear direction or the left-right direction of the electric vehicle, and the depth direction of the storage portion and the second direction orthogonal to the first direction are arranged in the height direction of the electric vehicle. The length in the first direction is greater than the length in the second direction,
At least one surface of the barrier layer is provided with a corrosion-resistant film, and when the corrosion-resistant film is analyzed using time-of-flight secondary ion mass spectrometry, the peak intensity P _CePO4 derived ^from _CePO4- The ratio P _PO3/CePO4 of the peak intensity P _{PO3 derived from PO 3 − is} in the range of 80 to 120, or the ratio P PO2/ _CePO4 of the peak intensity P _PO2 derived from PO ₂ ⁻ to ^the peak intensity _{P CePO4} is It is characterized by being within the range of 90-150.

Further, according to the present invention, in the method for manufacturing an electricity storage device having the above configuration, the length of the storage portion in the first direction is 2 to 30 times the length in the second direction.

Further, according to the present invention, in the method for manufacturing an electricity storage device having the above configuration, the step of packaging with the exterior member includes forming a peripheral edge seal portion for sealing the exterior member by heat sealing of the heat-fusible resin layer on the exterior member. It is characterized in that the peripheral edge seal portion formed on the peripheral portion and extending in the second direction is bent and overlapped on the peripheral wall of the storage portion.

Further, according to the present invention, in the method for manufacturing an electricity storage device having the above structure, the first direction is perpendicular to the flow direction of the exterior member.

According to the present invention, the power storage device is arranged in the depth direction of the housing portion of the exterior member and the first direction orthogonal to the depth direction is the front-rear direction or the left-right direction of the electric vehicle. Also, the depth direction of the storage section and the second direction orthogonal to the first direction are arranged in the height direction of the electric vehicle. Thereby, desired power can be supplied by installing a plurality of power storage devices in an electric vehicle without stacking them. Therefore, it is possible to prevent the exterior member from being damaged due to the load when the power storage devices are stacked.

In addition, when the corrosion-resistant film disposed on the surface of the barrier layer of the exterior member is analyzed using time-of-flight secondary ion mass spectrometry, the peak intensity P derived from CePO ₄ ⁻ derived from PO ₃ ⁻ relative to _CePO4 The ratio P _{PO3 /CePO4} of the peak intensity P PO3 is in the range of 80 to 120, or the ratio P PO2 / _CePO4 of the peak intensity P _PO2 derived from PO ₂ ^- to the peak intensity P _CePO4 is in the range of 90 to 150 be. Therefore, an exterior member having excellent adhesion of the barrier layer can be obtained. Therefore, the reliability of the electricity storage device, the electricity storage device assembly, and the electric vehicle can be improved.

Further, according to the exterior member for an electricity storage device of the present invention, the exterior member is formed of a laminate in which a corrosion-resistant film is arranged on the surface of a barrier layer, and has a storage portion and a flange portion. Further, the length of the storage portion in the first direction is greater than the length of the storage portion in the second direction orthogonal to the first direction in a plane perpendicular to the depth direction of the storage portion, and the flow direction of the laminate is orthogonal to the first direction. do. As a result, the peripheral seal portion is formed by heat-sealing the flange portion, and when the peripheral seal portion extending in the first direction is bent, pinholes and cracks in the electrical storage device exterior member can be reduced.

In addition, when the corrosion-resistant film disposed on the surface of the barrier layer is analyzed using time-of-flight secondary ion mass spectrometry, the peak intensity P derived from CePO ₄ ⁻ derived from _{CePO 4} − derived from PO ₃ ⁻ relative to CePO4 The ratio P _PO3/CePO4 of _PO3 is in the range of 80-120, or the ratio P _{PO2/CePO4 of} the peak intensity P _PO2 derived from PO ₂ ⁻ to the peak intensity P CePO4 is in the range of 90-150. Therefore, an exterior member for an electricity storage device having excellent adhesion of the barrier layer can be obtained. Therefore, the yield of the electric storage device can be improved and the reliability can be improved.

1 is a side view showing an electric vehicle according to a first embodiment of the present invention; FIG. 1 is a top view showing an electric vehicle according to a first embodiment of the present invention; FIG. 1 is a perspective view showing an electric storage device pack for an electric vehicle according to a first embodiment of the present invention; FIG. 1 is an exploded perspective view showing a power storage device for an electric vehicle according to a first embodiment of the present invention; FIG. BRIEF DESCRIPTION OF THE DRAWINGS Side cross-sectional view showing an electric storage device for an electric vehicle according to a first embodiment of the present invention. FIG. 1 is a cross-sectional view showing a packaging material for an exterior member of an electric storage device for an electric vehicle according to a first embodiment of the present invention; FIG. 4 is a cross-sectional view showing another packaging material for the exterior member of the power storage device of the electric vehicle according to the first embodiment of the present invention; FIG. 4 is a cross-sectional view showing still another packaging material for the exterior member of the power storage device of the electric vehicle according to the first embodiment of the present invention; FIG. 4 is a cross-sectional view showing still another packaging material for the exterior member of the power storage device of the electric vehicle according to the first embodiment of the present invention; FIG. 4 is a cross-sectional view showing still another packaging material for the exterior member of the power storage device of the electric vehicle according to the first embodiment of the present invention; FIG. 4 is an exploded perspective view showing an electric storage device for an electric vehicle according to a second embodiment of the present invention; FIG. 2 is a side cross-sectional view showing a power storage device for an electric vehicle according to a second embodiment of the present invention; FIG. 4 is a side cross-sectional view showing a state in which a power storage device of an electric vehicle according to a second embodiment of the present invention is covered with a protective cover; FIG. 11 is a side cross-sectional view showing a state in which the power storage device of the electric vehicle according to the second embodiment of the present invention is covered with another protective cover; FIG. 5 is an exploded perspective view showing an electric storage device for an electric vehicle according to a third embodiment of the present invention; FIG. 4 is a top view showing an electric vehicle according to a fourth embodiment of the present invention;

<First Embodiment>
Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show a side view and a top view of an electric vehicle 1 of the first embodiment. The electric vehicle 1 includes a drive motor 3 as a power source for driving wheels 2 . Under the floor of the vehicle body of the electric vehicle 1, an electricity storage device pack 5 (electricity storage device assembly) is installed as a drive source for supplying electric power to the drive motor 3. As shown in FIG.

FIG. 3 shows a perspective view of the electricity storage device pack 5. As shown in FIG. The power storage device pack 5 has a plurality of power storage devices 10 arranged side by side and is covered with an exterior container 6 . The power storage device pack 5 may be configured by arranging a plurality of power storage device modules in which a plurality of power storage devices 10 are packaged.

Each electricity storage device 10 is provided with a positive electrode terminal 12 and a negative electrode terminal 13 (see FIG. 4) made of metal. The electrode terminals 12 and 13 are electrically connected in a predetermined order, and a pair of connection terminals (not shown) protrude from the outer container 6 .

The external container 6 is formed of a laminate obtained by laminating a heat-fusible resin layer, a metal foil, and a base material layer. The space between each power storage device 10 and the exterior container 6 is filled with a filler (not shown), and the heat-sealable resin layer is heat-sealed to seal the exterior container 6 . Note that the exterior container 6 may be formed by injection molding.

4 and 5 show an exploded perspective view and a side sectional view of the electricity storage device 10. FIG. The power storage device 10 is composed of a secondary battery in which a power storage element 11 is enclosed in an exterior member 20 . Examples of the electric storage device 10 include lithium ion batteries, lithium ion polymer batteries, lithium ion all-solid-state batteries, lead storage batteries, nickel hydrogen storage batteries, nickel cadmium storage batteries, nickel iron storage batteries, nickel zinc storage batteries, silver zinc oxide storage batteries, metal air batteries, and many others. A cation battery or the like is used.

The storage element 11 is formed by arranging a positive electrode plate and a negative electrode plate (both not shown) facing each other with an insulating separator (not shown) interposed therebetween. Electrode terminals 12 and 13 are connected to the positive plate and the negative plate, respectively. The storage element 11 can be formed by winding a long separator, a positive electrode plate, and a negative electrode plate. The storage element 11 may be formed by laminating a sheet-shaped positive electrode plate, a separator, a negative electrode plate, and a separator in this order. Alternatively, the storage element 11 may be formed by stacking a long separator, a positive electrode plate, and a negative electrode plate by folding.

An electrolyte is arranged between the positive plate and the negative plate. In this embodiment, the electrolyte is an electrolytic solution and is filled inside the exterior member 20 . A solid electrolyte or a gel electrolyte may be used as the electrolyte.

The exterior member 20 includes a packaging material 15 (first packaging material) and a packaging material 25 (second packaging material) which are laminates having a heat-sealable resin layer 38 (see FIG. 6) on the inner surface.

FIG. 6 is a sectional view showing the laminated structure of the packaging material 15. As shown in FIG. The packaging material 25 has the same laminated structure as the packaging material 15 . The packaging material 15 and the packaging material 25 are each composed of a laminate having at least a substrate layer 34, a barrier layer 36, and a heat-fusible resin layer 38 in this order. The substrate layer 34 is the outermost layer, and the heat-fusible resin layer 38 is the innermost layer. That is, the heat-sealable resin layers 38 located at the peripheral edges of the storage element 11 are heat-sealed to seal the storage device 10 .

A corrosion-resistant film 36 a is provided on at least one surface of the barrier layer 36 . The corrosion-resistant film 36a contains cerium. In the packaging material 15 shown in FIG. 6, a corrosion-resistant film 36a is arranged on the surface of the barrier layer 36 on the heat-fusible resin layer 38 side.

Note that the packaging materials 15 and 25 may have other laminated structures. For example, packaging materials 15 and 25 shown in FIG. 7 have corrosion-resistant coatings 36a and 36b on both sides of barrier layer 36, respectively. At this time, as shown in FIG. 8, an adhesive layer 35 may be provided between the base material layer 34 and the barrier layer 36 as necessary for the purpose of enhancing adhesion. Further, as shown in FIG. 9, an adhesive layer 37 may be provided between the barrier layer 36 and the heat-fusible resin layer 38 as necessary for the purpose of enhancing adhesiveness.

Further, as shown in FIG. 10, a surface coating layer is optionally formed on the opposite side of the base material layer 34 from the barrier layer 36 for the purpose of improving design, electrolyte resistance, abrasion resistance, moldability, etc. 32 may be provided. At this time, the surface covering layer 32 becomes the outermost layer.

7 to 10, the corrosion-resistant coating 36a may be omitted and only the surface of the barrier layer 36 facing the substrate layer 34 may be provided with the corrosion-resistant coating 36b.

Although the thickness of the laminate constituting the packaging materials 15 and 25 is not particularly limited, it is preferably 60 μm or more in consideration of strength, and preferably 400 μm or less in consideration of weight reduction of the electricity storage device 10 . More preferably, the thickness of the packaging materials 15 and 25 is about 180 μm or less, and even more preferably about 150 μm or less. As a result, the packaging materials 15 and 25 having excellent moldability can be obtained while increasing the energy density of the power storage device 10 by reducing the thickness of the packaging materials 15 and 25 .

In addition, in the exterior material for an electric storage device, the vertical direction (MD) and the horizontal direction (TD) in the normal manufacturing process can be discriminated based on the barrier layer 36, which will be described later in detail. For example, when the barrier layer 36 is made of aluminum foil, linear streaks called rolling marks are formed on the surface of the aluminum foil. Since the rolling marks extend along the rolling direction (RD) of the aluminum foil, the rolling direction can be grasped by observing the surface of the aluminum foil.

In addition, in the manufacturing process of the laminate, the MD of the laminate and the RD of the aluminum foil usually match. Therefore, the MD of the laminate can be specified by observing the surface of the aluminum foil of the laminate and specifying the rolling direction (RD). Moreover, since the TD of the laminate is perpendicular to the MD, the TD of the laminate can also be specified.

(Base material layer 34)
The base material layer 34 of the packaging materials 15 and 25 is the outermost layer. A material for forming the base material layer 34 is not particularly limited as long as it has insulating properties. Materials for forming the base material layer 34 include polyester resin, polyamide resin, epoxy resin, acrylic resin, fluorine resin, polyurethane resin, silicon resin, phenol resin, polycarbonate resin, and resin films such as mixtures and copolymers thereof. is mentioned.

Among these, polyester resins and polyamide resins are preferred, and biaxially stretched polyester resins and biaxially stretched polyamide resins are more preferred. Specific examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, and copolymerized polyester. Specific examples of polyamide resins include nylon 6, nylon 66, copolymers of nylon 6 and nylon 66, nylon 6,10, and polyamide MXD6 (polymetaxylylene adipamide).

The substrate layer 34 may be formed of a single layer of resin film, but may be formed of two or more layers of resin film in order to improve pinhole resistance and insulation. Specific examples include a multilayer structure in which a polyester film and a nylon film are laminated, a multilayer structure in which a plurality of nylon films are laminated, a multilayer structure in which a plurality of polyester films are laminated, and the like.

When the substrate layer 34 has a multi-layer structure, a laminate of a biaxially oriented nylon film and a biaxially oriented polyester film, a laminate of a plurality of biaxially oriented nylon films, and a laminate of a plurality of biaxially oriented polyester films. body is preferred.

For example, when the base material layer 34 is formed from two layers of resin films, a structure in which polyester resin and polyester resin are laminated, a structure in which polyamide resin and polyamide resin are laminated, or a structure in which polyester resin and polyamide resin are laminated. It is preferable to It is more preferable to have a structure in which polyethylene terephthalate and polyethylene terephthalate are laminated, a structure in which nylon and nylon are laminated, or a structure in which polyethylene terephthalate and nylon are laminated.

In addition, since the polyester resin does not easily discolor when the electrolytic solution adheres to the surface, it is preferable to laminate the base material layer 34 so that the polyester resin is located in the outermost layer. When the substrate layer 34 has a multilayer structure, the thickness of each layer is preferably about 2 to 25 μm.

When the substrate layer 34 is formed of multiple layers of resin films, two or more resin films may be laminated via an adhesive component such as an adhesive or an adhesive resin. The type, amount, etc. of the adhesive component used for lamination are the same as in the case of the adhesive layer 35, which will be described later. The method for laminating two or more layers of resin films is not particularly limited, and known methods can be employed. For example, a dry lamination method, a sandwich lamination method, a co-extrusion lamination method and the like can be mentioned, and a dry lamination method is preferred. When laminating by a dry lamination method, it is preferable to use a urethane-based adhesive as the adhesive layer. At this time, the thickness of the adhesive layer is, for example, about 2 to 5 μm.

From the viewpoint of improving the moldability of the packaging materials 15 and 25, it is preferable that the surface of the base material layer 34 is coated with a lubricant. Lubricants are not particularly limited, but amide-based lubricants are preferred. Specific examples of the amide-based lubricant are the same as those exemplified for the heat-fusible resin layer 38 described later.

When the lubricant exists on the surface of the base material layer 34, the amount of the lubricant is not particularly limited, but it is preferable to use about 3 mg/m ² or more in an environment with a temperature of 24° C. and a relative humidity of 60%. More preferably, the amount of lubricant present is about 4 to 15 mg/m ² , more preferably about 5 to 14 mg/m ² .

A lubricant may be contained in the base layer 34 . The lubricant present on the surface of the substrate layer 34 may be the lubricant contained in the resin constituting the substrate layer 34 that is oozed out, or the surface of the substrate layer 34 may be coated with the lubricant. may

The thickness of the base material layer 34 is not particularly limited as long as the function of the base material layer 34 is exhibited.

(Adhesive layer 35)
The adhesive layer 35 is a layer provided between the substrate layer 34 and the barrier layer 36 as necessary in order to firmly bond them. The adhesive layer 35 is formed of an adhesive capable of bonding the base layer 34 and the barrier layer 36 together. The adhesive used to form the adhesive layer 35 may be a two-component curing adhesive or a one-component curing adhesive. The adhesive may be of chemical reaction type, solvent volatilization type, hot melt type, hot pressure type, or the like.

Examples of adhesive components that can be used to form the adhesive layer 35 include polyester-based resins, polyether-based resins, polyurethane-based resins, epoxy-based resins, phenolic-based resins, polycarbonate-based resins, polyamide-based resins, polyolefin-based resins, and polyvinyl acetate. resins, cellulose adhesives, (meth)acrylic resins, polyimide resins, amino resins, silicone resins, rubbers and the like.

Examples of polyester-based resins include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymerized polyester.

Polyamide-based resins include nylon 6, nylon 66, nylon 12, copolyamide, and the like. Examples of polyolefin-based resins include polyolefins, carboxylic acid-modified polyolefins, and metal-modified polyolefins.

Examples of amino resins include urea resins and melamine resins. Examples of rubber include chloroprene rubber, nitrile rubber, styrene-butadiene rubber, and the like.

These adhesive components may be used singly or in combination of two or more. In addition, an appropriate curing agent can be used in combination with these adhesive component resins to increase the adhesive strength. The curing agent is selected from among polyisocyanates, polyfunctional epoxy resins, oxazoline group-containing polymers, polyamine resins, acid anhydrides, etc., depending on the functional groups of the adhesive component.

These adhesive components and curing agents are preferably polyurethane adhesives comprising various polyols (adhesive components having hydroxyl groups) and polyisocyanates. More preferably, a two-component curing type polyurethane adhesive is used, which uses a polyol such as polyester polyol, polyether polyol, or acrylic polyol as a main component and an aromatic or aliphatic polyisocyanate as a curing agent.

The adhesive layer 35 may contain a coloring agent such as a pigment. The thickness of the adhesive layer 35 is not particularly limited as long as it functions as an adhesive layer.

(Barrier layer 36)
The barrier layer 36 is a layer having a function of improving the strength and preventing water vapor, oxygen, light, etc. from entering the electricity storage device 10 . The barrier layer 36 is preferably a metal layer, that is, a layer made of metal. Specific examples of the metal forming the barrier layer 36 include aluminum (including aluminum alloys), stainless steel, titanium, and the like, preferably aluminum.

The barrier layer 36 can be formed of, for example, a metal foil, a metal deposition film, a film provided with these deposition films, or the like. The barrier layer 36 is preferably made of metal foil, more preferably made of aluminum foil.

The barrier layer 36 is formed of soft aluminum foil such as annealed aluminum (JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, JIS H4000:2014 A8079P-O). is more preferable. This can prevent wrinkles and pinholes from occurring in the barrier layer 36 when the packaging materials 15 and 25 are manufactured.

The thickness of the barrier layer 36 is not particularly limited as long as it functions as a barrier layer against water vapor or the like, but from the viewpoint of reducing the thickness of the packaging materials 15 and 25, it is preferably about 100 μm or less, more preferably about 10 to 100 μm, and even more preferably about 10 to 100 μm. is about 10 to 80 μm.

(Corrosion-resistant coatings 36a, 36b)
The packaging materials 15 and 25 have a corrosion-resistant coating on at least one surface of the barrier layer 36 . Only the surface of the barrier layer 36 on the heat-sealable resin layer 38 side may be provided with the corrosion-resistant film 36a. Only the surface of the barrier layer 36 on the substrate layer 34 side may be provided with the corrosion-resistant coating 36b. Both sides of the barrier layer 36 may be provided with corrosion resistant coatings 36a, 36b, respectively.

When water enters the power storage device 10, the water may react with the electrolyte or the like to generate an acidic substance. For example, when the electricity storage device 10 is a lithium ion battery or the like, the electrolyte contains a fluorine compound (LiPF ₆ , LiBF _{4 ,} etc.) as an electrolyte. At this time, if moisture enters the power storage device 10, the fluorine compound reacts with the water to generate hydrogen fluoride.

The barrier layer 36 formed of metal foil or the like is easily corroded when it comes into contact with acid. Therefore, the corrosion resistance of the packaging materials 15 and 25 can be improved by forming a corrosion-resistant film 36a on the surface of the barrier layer 36 by chemical conversion treatment.

Also, by providing the corrosion-resistant coating 36b, the adhesion between the corrosion-resistant coating 36b on the surface of the barrier layer 36 and the substrate layer 34 or the adhesive layer 35 can be enhanced. This can prevent delamination of the base layer 34 and the barrier layer 36 when exposed to high temperature and high humidity conditions.

As chemical conversion treatments for forming the corrosion-resistant films 36a and 36b, methods such as chromate treatment using a chromium compound such as chromium oxide and phosphate treatment using a phosphoric acid compound are known.

A conventional barrier layer provided with a corrosion-resistant coating may have insufficient adhesion to the layer adjacent to the side on which the corrosion-resistant coating is provided (i.e., adhesion at the interface between the corrosion-resistant coating and the layer in contact with it). be. More specifically, the adhesion may become insufficient due to the electrolytic solution adhering to the packaging materials 15 and 25 .

Therefore, when the corrosion-resistant coatings 36a and 36b are analyzed using time-of- ^flight secondary ion mass spectrometry, the ratio of the peak intensity P _PO3 derived from PO ₃ ⁻ to the peak intensity P _CePO4 derived from CePO _{4 −} P _PO3/CePO4 is in the range of 80-120, or the ratio P _{PO2 /} CePO4 of the peak intensity P _PO2 derived from PO ₂ ⁻ to the peak intensity P CePO4 is in the range of 90-150.

As a result, even when the electrolytic solution adheres to the packaging materials 15 and 25, it is possible to prevent deterioration in the adhesion between the barrier layer 36 and the layers adjacent to the side on which the corrosion-resistant films 36a and 36b are provided. That is, by setting the ratio P _{PO3 /CePO4} within the range of 80 to 120 or the ratio P _{PO2 /CePO4} within the range of 90 to 150, the layer adjacent to the side on which the barrier layer 36 and the corrosion resistant films 36a and 36b are provided It is possible to obtain packaging materials 15 and 25 that are excellent in adhesion to.

When both sides of the barrier layer 36 are provided with corrosion-resistant coatings 36a and 36b, the peak strength ratio _PPO3/CePO4 or the ratio _PPO2/CePO4 of the corrosion-resistant coating on either side must be within the above range. I wish I had. However, it is more preferable that the peak intensity ratio _PPO3/CePO4 or the ratio _PPO2/CePO4 of both of the corrosion resistant coatings 36a, 36b be within the above range.

In particular, the corrosion-resistant film 36a located on the heat-fusible resin layer 38 side of the barrier layer 36 and the layer adjacent thereto (adhesive layer 37 or heat-fusible resin layer 38) are separated by permeation of the electrolytic solution. Adhesion tends to decrease. For this reason, it is preferable that at least the surface of the barrier layer 36 on the heat-fusible resin layer 38 side is provided with a corrosion-resistant film 36a. The peak intensity ratio _PPO2/CePO4 or the ratio _PPO3/CePO4 of the corrosion-resistant coating 36a is preferably within the above range. These points also apply to the peak intensity ratios shown below.

The peak intensity ratio _PPO3/CePO4 may be in the range of 80 to 120, but from the viewpoint of further increasing the adhesion of the barrier layer 36 having a corrosion-resistant film, the lower limit is preferably about 85, and more preferably about 92. . The upper limit of the ratio _PPO3/CePO4 is preferably about 110, more preferably about 105, and even more preferably about 98. That is, the preferred range of the ratio _PPO3/CePO4 is about 80 to 110, about 80 to 105, about 80 to 98, about 85 to 120, about 85 to 110, about 85 to 105, about 85 to 98, and 92 to 120. about 92 to 110, about 92 to 105, and about 92 to 98.

The peak intensity ratio P _{PO2 /CePO4} may be in the range of 90 to 150, but from the viewpoint of further increasing the adhesion of the barrier layer 36 having a corrosion-resistant film, the lower limit is preferably about 110, and the upper limit is about 110. 130 is preferred. More preferably, the upper limit of the ratio _PPO2/CePO4 is about 116. That is, preferable ranges of the ratio P _{PO2 /CePO4} include about 90 to 130, about 90 to 116, about 110 to 150, about 110 to 130, and about 110 to 116.

Analysis using time-of-flight secondary ion mass spectrometry can be specifically performed using a time-of-flight secondary ion mass spectrometer under the following measurement conditions.

Primary ions: Double charged ions of bismuth clusters (Bi ₃ ⁺⁺ )
Primary ion acceleration voltage: 30 kV
Mass range (m/z): 0-1500
Measurement range: 100 μm×100 μm
Number of scans: 16 scans/cycle
Number of pixels (one side): 256 pixels
Etching ion: Ar gas cluster ion beam (Ar-GCIB)
Etching ion acceleration voltage: 5.0 kV

In addition, it can be confirmed by X-ray photoelectron spectroscopy that the corrosion-resistant films 36a and 36b contain cerium. Specifically, the layers laminated on the barrier layer 36 (the adhesive layer 35, the heat-fusible resin layer 38, the adhesive layer 37, etc.) are physically peeled off. Next, the barrier layer 36 is placed in an electric furnace, and organic components present on the surface of the barrier layer 36 are removed at about 300° C. for about 30 minutes. The inclusion of cerium is then confirmed using X-ray photoelectron spectroscopy of the surface of the barrier layer 36 .

The corrosion-resistant coatings 36a and 36b can be formed by subjecting the surface of the barrier layer 36 to chemical conversion treatment with a treatment liquid containing a cerium compound such as cerium oxide. For example, a treatment liquid in which a cerium compound such as cerium oxide is dispersed in phosphoric acid and/or a salt thereof dissolved in a solvent is applied to the surface of the barrier layer 36 and baked. Corrosion-resistant coatings 36a and 36b are thereby formed on the surface of the barrier layer 36 by chemical conversion treatment.

Examples of the method of applying the treatment liquid containing the cerium compound to the surface of the barrier layer 36 include a bar coating method, a roll coating method, a gravure coating method, and an immersion method.

The ratio _PPO3/CePO4 or the ratio _PPO2/CePO4 of the peak intensity of the corrosion-resistant films 36a and 36b is adjusted by, for example, the composition of the treatment solution for forming the corrosion-resistant films 36a and 36b, the conditions (temperature, time, etc.) of the baking treatment, and the like. be able to.

The ratio of the cerium compound to the phosphoric acid and/or its salt in the treatment liquid containing the cerium compound is not particularly limited, but the above ratio _PPO3/CePO4 or the ratio _PPO2/CePO4 is set within the above range. adjusted to For example, the amount of phosphoric acid and/or its salt is preferably about 12 to 28 parts by mass, more preferably about 15 to 25 parts by mass, relative to 100 parts by mass of the cerium compound. Condensed phosphoric acid or its salt, for example, can be used as the phosphoric acid or its salt contained in the treatment liquid.

Moreover, the treatment liquid containing the cerium compound may further contain an anionic polymer and a cross-linking agent for cross-linking the anionic polymer. Examples of anionic polymers include poly(meth)acrylic acid or its salts, copolymers containing (meth)acrylic acid or its salts as main components, and the like. Examples of cross-linking agents include compounds having functional groups such as isocyanate groups, glycidyl groups, carboxyl groups, and oxazoline groups, and silane coupling agents. Each of the anionic polymer and the cross-linking agent may be of one kind, or two or more kinds thereof may be used.

Moreover, from the viewpoint of enhancing the adhesion of the barrier layer 36 while exhibiting excellent corrosion resistance, the treatment liquid containing the cerium compound preferably contains an aminated phenol polymer. In the treatment liquid containing a cerium compound, the amount of aminated phenol polymer is preferably about 100 to 400 parts by mass, more preferably about 200 to 300 parts by mass, per 100 parts by mass of the cerium compound.

Further, the weight average molecular weight of the aminated phenol polymer is preferably about 5,000 to 20,000. The weight average molecular weight of the aminated phenolic polymer is a value measured by gel permeation chromatography (GPC) using polystyrene as a standard sample.

The solvent for the treatment liquid containing the cerium compound is not particularly limited as long as it disperses the components contained in the treatment liquid and is then evaporated by heating, but water is preferred.

Although the solid content concentration of the treatment liquid containing the cerium compound is not particularly limited, it can be, for example, about 8 to 30% by mass. The solid concentration of the treatment liquid is more preferably about 9.0 to 10.0 parts by mass, more preferably about 9.1 to 9.5 parts by mass, per 100 parts by mass of the solvent (water or the like). Thereby, the ratio P _{PO3 /CePO4} or the ratio P _{PO2 /CePO4} of the peak intensity can be set within the above-mentioned predetermined range, and the adhesion of the barrier layer 36 can be enhanced while exhibiting excellent corrosion resistance.

The surface temperature of the barrier layer 36 during baking is preferably about 170 to 250.degree. C., more preferably about 180 to 230.degree. C., still more preferably about 190 to 220.degree. The heating time of the barrier layer 36 during baking is preferably about 2 to 10 seconds, more preferably about 3 to 6 seconds. By adopting such temperature and heating time, the solvent can be properly evaporated and the corrosion-resistant coatings 36a and 36b can be preferably formed. As a result, the ratio P _{PO3 /CrPO4} or the ratio P _{PO2 /CrPO4} of the peak intensity can be set within the predetermined ranges, and the long-term adhesion of the barrier layer 36 can be enhanced while exhibiting excellent corrosion resistance.

Further, from the viewpoint of performing the chemical conversion treatment on the surface of the barrier layer 36 more efficiently, before providing the corrosion-resistant coatings 36a and 36b on the surface of the barrier layer 36, an alkaline immersion method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid It is preferable to carry out the degreasing treatment by a known treatment method such as a washing method or an acid activation method.

Although the thickness of the corrosion-resistant films 36a and 36b is not particularly limited, it is preferably about 1 nm to 10 μm from the viewpoint of improving adhesion of the barrier layer 36 while exhibiting excellent corrosion resistance. The thickness of the corrosion-resistant coatings 36a and 36b is more preferably about 1-100 nm, more preferably about 1-50 nm. The thickness of the corrosion-resistant films 36a and 36b can be measured by observation with a transmission electron microscope. Alternatively, the thickness of the corrosion-resistant coatings 36a, 36b can be measured by a combination of transmission electron microscope observation and energy dispersive X-ray spectroscopy or electron beam energy loss spectroscopy.

From the same point of view, the amount of the corrosion-resistant films 36a and 36b per 1 m ² of the surface of the barrier layer 36 is preferably about 2-100 mg, more preferably about 2-70 mg, and even more preferably about 2-40 mg.

(Heat-fusible resin layer 38)
The heat-fusible resin layer 38 corresponds to the innermost layer of the packaging materials 15 and 25, and is a layer that seals the power storage device 10 by heat-fusibly bonding the heat-fusible resin layers 38 to each other.

The resin component used for the heat-sealable resin layer 38 is not particularly limited as long as it can be heat-sealed, but a polyolefin resin can be used. Examples of polyolefin-based resins include polyolefins, cyclic polyolefins, acid-modified polyolefins, and acid-modified cyclic polyolefins. That is, the resin forming the heat-fusible resin layer 38 may not contain a polyolefin skeleton, but preferably contains a polyolefin skeleton.

The inclusion of a polyolefin skeleton in the resin forming the heat-fusible resin layer 38 can be analyzed by, for example, infrared spectroscopy, gas chromatography mass spectrometry, or the like. Analysis methods are not limited to these. For example, when maleic anhydride-modified polyolefin is measured by infrared spectroscopy, peaks derived from maleic anhydride are detected near wavenumbers of 1760 cm ⁻¹ and 1780 cm ⁻¹ . However, if the degree of acid denaturation is low, the peak may be too small to be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

Specific examples of polyolefins include polyethylene, polypropylene, and terpolymers of ethylene-butene-propylene. Examples of polyethylene include low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, and the like. Polypropylene includes homopolypropylene, block copolymers of polypropylene (eg, block copolymers of propylene and ethylene), random copolymers of polypropylene (eg, random copolymers of propylene and ethylene), and the like. Among these polyolefins, polyethylene and polypropylene are preferred.

Cyclic polyolefins are copolymers of olefins and cyclic monomers. Examples of olefins that are constituent monomers of cyclic polyolefins include ethylene, propylene, 4-methyl-1-pentene, butadiene and isoprene. Examples of cyclic monomers that are constituent monomers of cyclic polyolefins include cyclic alkenes and cyclic dienes. Cyclic alkenes include, for example, norbornene. Cyclic dienes include cyclopentadiene, dicyclopentadiene, cyclohexadiene, norbornadiene, and the like. Among these cyclic monomers, cyclic alkenes are preferred, and norbornene is more preferred.

Acid-modified polyolefin is a polymer modified by block copolymerization or graft copolymerization of polyolefin with an acid component such as carboxylic acid. Examples of acid components used for modification include carboxylic acids such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride and itaconic anhydride, and anhydrides thereof.

Acid-modified cyclic polyolefin is a polymer obtained by copolymerizing a part of monomers constituting cyclic polyolefin in place of α,β-unsaturated carboxylic acid or its anhydride. Alternatively, the acid-modified cyclic polyolefin is a polymer obtained by block-polymerizing or graft-polymerizing an α,β-unsaturated carboxylic acid or its anhydride to a cyclic polyolefin. The carboxylic acid-modified cyclic polyolefin is the same as described above. Also, the carboxylic acid used for modification is the same as that used for modifying the acid-modified polyolefin.

As the resin constituting the heat-fusible resin layer 38, polyolefins such as polypropylene and carboxylic acid-modified polyolefins are particularly preferable among those mentioned above. Polypropylene and acid-modified polypropylene are more preferred.

The heat-fusible resin layer 38 may be formed of one resin component alone, or may be formed of a blend polymer in which two or more resin components are combined. Furthermore, the heat-fusible resin layer 38 may be formed of only one layer, but may be formed of two or more layers of the same or different resin components.

Moreover, it is preferable that a lubricant is adhered to the surface of the heat-fusible resin layer 38 . Thereby, the moldability of the packaging material 15 can be improved. Lubricants are not particularly limited, but amide-based lubricants are preferred. Examples of amide lubricants include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylolamides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides. Lubricants may be used singly or in combination of two or more.

Specific examples of saturated fatty acid amides include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, and hydroxystearic acid amide. Specific examples of unsaturated fatty acid amides include oleic acid amide and erucic acid amide.

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, N-stearyl erucic acid amide and the like. Specific examples of methylolamides include methylol stearamide and the like.

Specific examples of saturated fatty acid bisamides include methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, ethylenebisstearic acid amide, ethylenebishydroxystearic acid amide, ethylenebisbehenic acid amide, and hexamethylenebisstearic acid. amide, hexamethylenebisbehenic acid amide, hexamethylenehydroxystearic acid amide, N,N'-distearyladipic acid amide, N,N'-distearylsebacic acid amide and the like.

Specific examples of unsaturated fatty acid bisamides include ethylenebisoleic acid amide, ethylenebiserucic acid amide, hexamethylenebisoleic acid amide, N,N'-dioleyladipic acid amide, N,N'-dioleylsebacic acid amide, and the like. is mentioned.

Specific examples of fatty acid ester amides include stearamide ethyl stearate. Specific examples of aromatic bisamides include m-xylylenebisstearic acid amide, m-xylylenebishydroxystearic acid amide, and N,N'-distearylisophthalic acid amide.

Although the amount of lubricant present on the surface of the heat-sealable resin layer 38 is not particularly limited, it is preferably approximately 3 mg/m ² or more in an environment of 24° C. and 60% relative humidity. The amount of lubricant present is more preferably about 4 to 15 mg/m ² , more preferably about 5 to 14 mg/m ² in an environment with a temperature of 24° C. and a relative humidity of 60%.

Also, a lubricant may be contained in the heat-fusible resin layer 38 . The lubricant present on the surface of the heat-fusible resin layer 38 may be applied or the lubricant contained in the resin constituting the heat-fusible resin layer 38 may be exuded.

The thickness of the heat-fusible resin layer 38 is not particularly limited as long as it functions as a heat-fusible resin layer. mentioned.

(Adhesion layer 37)
The adhesive layer 37 is a layer provided between the barrier layer 36 and the heat-fusible resin layer 38 as necessary in order to enhance the adhesion between them. The adhesive layer 37 may be composed of a single layer, or may be composed of multiple layers that are the same or different.

In general, from the viewpoint of enhancing the adhesion between the barrier layer 36 and the heat-fusible resin layer 38, it is preferable to have an adhesive layer 37 between them. However, when the barrier layer 36 is provided with the corrosion-resistant film 36a on the surface of the heat-sealable resin layer 38, there is a problem that the adhesion between the corrosion-resistant film 36a and the adhesive layer 37 tends to decrease.

On the other hand, in the present embodiment, the corrosion-resistant film 36a has the specific peak intensity ratio _PPO3/CePO4 or the ratio _PPO2/CePO4 , and thus has excellent adhesion. Therefore, the adhesion between the corrosion-resistant film 36a and the adhesive layer 37 is effectively enhanced. That is, in the packaging materials 15 and 25 in which the corrosion-resistant film 36a on the surface of the barrier layer 36 and the heat-sealable resin layer 38 are laminated via the adhesive layer 37, the adhesion of the barrier layer 36 is excellent.

The adhesive layer 37 is made of a resin capable of bonding the barrier layer 36 (furthermore, the corrosion-resistant film 36a) and the heat-fusible resin layer 38 together. As the resin used to form the adhesive layer 37, the adhesive exemplified for the adhesive layer 35 or the polyolefin resin exemplified for the heat-sealable resin layer 38 can be used.

Examples of polyolefin-based resins include polyolefins, cyclic polyolefins, carboxylic acid-modified polyolefins, and carboxylic acid-modified cyclic polyolefins. That is, the resin forming the adhesive layer 37 preferably contains a polyolefin skeleton. From the viewpoint of excellent adhesion between the barrier layer 36 and the heat-fusible resin layer 38, polyolefin and carboxylic acid-modified polyolefin are preferable, and carboxylic acid-modified polypropylene is particularly preferable.

The fact that the resin forming the adhesive layer 37 contains a polyolefin skeleton can be analyzed by, for example, infrared spectroscopy, gas chromatography mass spectrometry, or the like. Analysis methods are not limited to these. For example, when maleic anhydride-modified polyolefin is measured by infrared spectroscopy, peaks derived from maleic anhydride are detected near wavenumbers of 1760 cm ⁻¹ and 1780 cm ⁻¹ . However, if the degree of acid denaturation is low, the peak may be too small to be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

Furthermore, from the viewpoint of making the packaging materials 15 and 25 excellent in shape stability after molding while reducing the thickness, the adhesive layer 37 is a cured product of a resin composition containing a main agent made of acid-modified polyolefin and a curing agent. may Preferred acid-modified polyolefins are carboxylic acid-modified polyolefins and carboxylic acid-modified cyclic polyolefins.

Moreover, the curing agent is not particularly limited as long as it cures the acid-modified polyolefin. Examples of curing agents include epoxy-based curing agents, polyfunctional isocyanate-based curing agents, carbodiimide-based curing agents, oxazoline-based curing agents, and the like.

The epoxy-based curing agent is not particularly limited as long as it is a compound having at least one epoxy group. Specific examples of epoxy-based curing agents include epoxy resins such as bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, novolac glycidyl ether, glycerin polyglycidyl ether, and polyglycerin polyglycidyl ether.

The polyfunctional isocyanate curing agent is not particularly limited as long as it is a compound having two or more isocyanate groups. Specific examples of polyfunctional isocyanate curing agents include isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymers and nurates thereof, and mixtures thereof. and copolymers with other polymers.

The carbodiimide curing agent is not particularly limited as long as it is a compound having at least one carbodiimide group (-N=C=N-). A specific example of the carbodiimide curing agent is preferably a polycarbodiimide compound having at least two carbodiimide groups.

The oxazoline curing agent is not particularly limited as long as it is a compound having an oxazoline skeleton (oxazoline group). Compounds having an oxazoline group include those having a polystyrene main chain and those having an acrylic main chain. Specifically, Epocross (registered trademark) series manufactured by Nippon Shokubai Co., Ltd. can be used.

From the viewpoint of enhancing the adhesion between the barrier layer 36 and the heat-fusible resin layer 38 by the adhesive layer 37, the curing agent may be composed of two or more kinds of compounds.

The content of the curing agent in the resin composition forming the adhesive layer 37 is preferably in the range of about 0.1 to 50 mass %. Also, the content of the curing agent is more preferably in the range of about 0.1 to 30% by mass, more preferably in the range of about 0.1 to 10% by mass.

That is, the adhesive layer 37 is a cured product of a resin composition containing a main agent made of acid-modified polyolefin and a curing agent, and the curing agent is composed of a compound having an isocyanate group, a compound having an oxazoline group, and a compound having an epoxy group. It is preferable to include at least one selected from the group. Furthermore, it is more preferable that the curing agent contains at least one selected from the group consisting of a compound having an isocyanate group and a compound having an epoxy group.

In some cases, an unreacted product of a curing agent such as an isocyanate group-containing compound, an oxazoline group-containing compound, or an epoxy resin may remain in the adhesive layer 37 . The presence of unreacted curing agent can be confirmed by methods such as infrared spectroscopy, Raman spectroscopy, time-of-flight secondary ion mass spectrometry (TOF-SIMS), and the like.

Also, the adhesive layer 37 may be made of resin containing at least one selected from the group consisting of urethane resin, ester resin and epoxy resin. More preferably, the adhesive layer 37 is a cured product of a resin composition containing at least one of these resins and an acid-modified polyolefin. Furthermore, it is more preferable that the adhesive layer 37 contains urethane resin and epoxy resin.

As the ester resin, for example, an amide ester resin is preferable. Amide ester resins are generally produced by the reaction of carboxyl groups and oxazoline groups.

In addition, from the viewpoint of further increasing the adhesion between the corrosion-resistant film 36a and the adhesive layer 37, the adhesive layer 37 is composed of at least It is preferably a cured product of a resin composition containing one curing agent.

The fact that the adhesive layer 37 is a cured product of a resin composition containing these curing agents can be confirmed by gas chromatography mass spectrometry (GCMS), infrared spectroscopy (IR), time-of-flight secondary ion mass spectrometry (TOF-SIMS). ) and X-ray photoelectron spectroscopy (XPS).

Curing agents having a heterocyclic ring include, for example, curing agents having an oxazoline group, curing agents having an epoxy group, and the like. Curing agents having a C═N bond include curing agents having an oxazoline group, curing agents having an isocyanate group, and the like. Curing agents having a C—O—C bond include curing agents having an oxazoline group, curing agents having an epoxy group, and urethane resins.

The curing agent having an oxazoline group is not particularly limited as long as it is a compound having an oxazoline skeleton. Compounds having an oxazoline group include those having a polystyrene main chain, those having an acrylic main chain, and the like. Specifically, the aforementioned Epocross series or the like can be used.

The ratio of the compound having an oxazoline group in the adhesive layer 37 is preferably in the range of 0.1 to 50% by mass, more preferably in the range of 0.5 to 40% by mass, in the resin composition constituting the adhesive layer 37. is more preferable. Thereby, the adhesion between the corrosion-resistant film 36a and the adhesive layer 37 can be effectively improved.

Although the curing agent having an isocyanate group is not particularly limited, polyfunctional isocyanate compounds are preferred from the viewpoint of effectively increasing the adhesion between the corrosion-resistant film 36a and the adhesive layer 37. The polyfunctional isocyanate compound is not particularly limited as long as it is a compound having two or more isocyanate groups. Specific examples of the polyfunctional isocyanate curing agent include those exemplified for the adhesive layer 35 described above.

The content of the compound having an isocyanate group in the adhesive layer 37 is preferably in the range of 0.1 to 50% by mass, more preferably in the range of 0.5 to 40% by mass, in the resin composition constituting the adhesive layer 37. It is more preferable to have Thereby, the adhesion between the corrosion-resistant film 36a and the adhesive layer 37 can be effectively improved.

The curing agent having an epoxy group is not particularly limited as long as it is a resin capable of forming a crosslinked structure with epoxy groups present in the molecule, and known epoxy resins can be used. The weight average molecular weight of the epoxy resin is preferably about 50-2000, more preferably about 100-1000, and still more preferably about 200-800.

In the present embodiment, the weight average molecular weight of the epoxy resin is a value measured by gel permeation chromatography (GPC) under conditions using polystyrene as a standard sample.

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

The ratio of the epoxy resin in the adhesive layer 37 is preferably in the range of 0.1 to 50% by mass, more preferably in the range of 0.5 to 40% by mass, in the resin composition constituting the adhesive layer 37. . Thereby, the adhesion between the corrosion-resistant film 36a and the adhesive layer 37 can be effectively improved.

The thickness of the adhesive layer 37 is not particularly limited as long as it functions as an adhesive layer. About 5 μm can be mentioned.

Further, when the resin exemplified for the heat-fusible resin layer 38 is used for the adhesive layer 37, the thickness of the adhesive layer 37 is preferably about 2 to 50 μm, more preferably about 10 to 40 μm.

In the case where a cured product of acid-modified polyolefin and a curing agent is used for the adhesive layer 37, the thickness of the adhesive layer 37 is preferably about 30 μm or less, more preferably about 0.1 to 20 μm, and still more preferably 0.1 μm or less. About 5 to 5 μm can be mentioned. When the adhesive layer 37 is a cured product of a resin composition containing acid-modified polyolefin and a curing agent, the adhesive layer 37 can be formed by applying the resin composition and curing it by heating or the like.

(Surface covering layer 32)
The packaging materials 15 and 25 are provided outside the base material layer 34 (on the side opposite to the barrier layer 36 of the base material layer 34) as necessary for the purpose of improving design, electrolyte resistance, abrasion resistance, and moldability. ) is provided with a surface coating layer 32 . When the surface coating layer 32 is provided, the surface coating layer 32 becomes the outermost layer of the packaging materials 15 and 25 .

The surface coating layer 32 can be made of, for example, polyvinylidene chloride, polyester resin, urethane resin, acrylic resin, epoxy resin, or the like. Among these, it is preferable to form the surface coating layer 32 with a two-liquid curing resin. Examples of the two-liquid curing resin forming the surface coating layer 32 include two-liquid curing urethane resin, two-liquid curing polyester resin, and two-liquid curing epoxy resin. Additives may also be added to the surface coating layer 32 .

Examples of additives include fine particles having a particle size of about 0.5 nm to 5 μm. Although the material of the additive is not particularly limited, examples thereof include metals, metal oxides, inorganic substances, organic substances, and the like. The shape of the additive is also not particularly limited, and examples thereof include spherical, fibrous, plate-like, amorphous, and balloon-like shapes.

Specific examples of additives include talc, silica, graphite, kaolin, montmorilloid, montmorillonite, synthetic 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, crosslinked acrylic, crosslinked styrene, crosslinked polyethylene, benzoguanamine, gold, aluminum, copper, nickel, and the like.

These additives may be used singly or in combination of two or more. Among these additives, silica, barium sulfate, and titanium oxide are preferred from the viewpoint of dispersion stability, cost, and the like. In addition, the surface of the additive may be subjected to various surface treatments such as insulation treatment and high-dispersion treatment.

Although the content of the additive in the surface coating layer 32 is not particularly limited, it is preferably about 0.05 to 1.0 mass %, more preferably about 0.1 to 0.5 mass %.

The method of forming the surface coating layer 32 is not particularly limited, but for example, a method of coating the outer surface of the substrate layer 34 with a two-liquid curable resin that forms the surface coating layer 32 can be used. When an additive is blended, the additive may be added to the two-liquid curing resin, mixed, and then applied.

The thickness of the surface coating layer 32 is not particularly limited as long as it exhibits the above function as the surface coating layer 32, and is, for example, approximately 0.5 to 10 μm, preferably approximately 1 to 5 μm.

(Manufacturing method of packaging materials 15 and 25)
The method of manufacturing the packaging materials 15 and 25 having the above-described configuration is not particularly limited as long as a laminate obtained by laminating each layer having a predetermined composition can be obtained. That is, it includes a step of laminating at least the substrate layer 34, the barrier layer 36, and the heat-fusible resin layer 38 in this order to obtain a laminate. Moreover, when laminating the barrier layer 36, the surface of at least one side of the barrier layer 36 is provided with a corrosion-resistant film. When the corrosion-resistant coatings 36a and 36b are analyzed using time-of-flight secondary ion mass spectrometry, the ratio P _{PO3 / CePO4} of the peak intensity P _PO3 derived from PO ₃ ⁻ to the peak intensity P CePO4 derived from CePO _{4 −} ^is obtained. is within the range of 80-120, or the ratio P _{PO2 / CePO4} of the peak intensity P _PO2 derived from PO ₂ ⁻ to the peak intensity P CePO4 is within the range of 90-150.

An example of a method of manufacturing the packaging materials 15 and 25 is shown below. First, a layered body (hereinafter sometimes referred to as "layered body A") is formed by laminating the substrate layer 34, the adhesive layer 35 provided as necessary, and the barrier layer 36 in this order.

Specifically, the laminate A is formed by a dry lamination method. An adhesive for forming the adhesive layer 35 is applied to one of the base material layer 34 and the barrier layer 36 (corrosion-resistant coating 36b when provided with a corrosion-resistant coating 36b, hereinafter omitted) and dried, and the other is laminated to form an adhesive layer. 35 is cured. Application of the adhesive is performed by a coating method such as gravure coating or roll coating. At this time, the aforementioned corrosion-resistant film is formed in advance on at least one surface of the barrier layer 36 . The method of forming the corrosion-resistant coatings 36a and 36b is as described above.

Next, a heat-fusible resin layer 38 is laminated on the barrier layer 36 of the laminate A. As shown in FIG. When the heat-fusible resin layer 38 is directly laminated on the barrier layer 36, the resin component constituting the heat-fusible resin layer 38 is applied onto the barrier layer 36 of the laminate A by a gravure coating method or a roll coating method. It may be applied by a method such as the following.

When the adhesive layer 37 is provided between the barrier layer 36 and the heat-fusible resin layer 38, the heat-fusible resin layer 38 is laminated by a coextrusion lamination method, a sandwich lamination method, a thermal lamination method, or the like. be.

In the co-extrusion lamination method, the adhesive layer 37 and the heat-fusible resin layer 38 are laminated on the barrier layer 36 of the laminate A by co-extrusion. In the sandwich lamination method, a melted adhesive layer 37 is poured between the barrier layer 36 of the laminate A and the heat-fusible resin layer 38 formed in advance into a sheet shape, and the laminate A and the heat-fusible resin layer 38 are separated. Paste.

In the thermal lamination method, a laminated body is formed by laminating the adhesive layer 37 and the heat-fusible resin layer 38, and this is laminated on the barrier layer 36 of the laminated body A in a heated state. An adhesive that forms an adhesive layer 37 may be laminated on the barrier layer 36 of the laminate A, and a heat-fusible resin layer 38 previously formed into a sheet may be laminated in a heated state. At this time, the adhesive layer 37 can be laminated by applying an adhesive on the laminate A by an extrusion method or solution coating, drying at a high temperature, and then baking.

When the surface coating layer 32 is provided, the surface coating layer 32 is laminated on the surface of the substrate layer 34 opposite to the barrier layer 36 . The surface coating layer 32 can be formed, for example, by coating the surface of the substrate layer 34 with a resin that forms the surface coating layer 32 . The order of the step of laminating the barrier layer 36 on the surface of the base layer 34 and the step of laminating the surface coating layer 32 on the surface of the base layer 34 is not particularly limited. For example, after forming the surface coating layer 32 on the surface of the base material layer 34 , the barrier layer 36 may be formed on the surface of the base material layer 34 opposite to the surface coating layer 32 .

As described above, the surface coating layer 32/base layer 34 provided as required/adhesive layer 35 provided as required/barrier layer 36 provided with a corrosion-resistant film on at least one surface/if required A laminated body is formed of the provided adhesive layer 37 and heat-fusible resin layer 38 . In order to strengthen the adhesiveness of the adhesive layer 35 and the adhesive layer 37, heat treatment such as hot roll contact, hot air, near-infrared or far-infrared heat treatment may be applied.

Each layer constituting the laminate may be subjected to surface activation treatment such as corona treatment, blast treatment, oxidation treatment, ozone treatment, etc., if necessary. As a result, it is possible to improve or stabilize the film formability of each layer, lamination processing, final product secondary processing (pouching, embossing) aptitude, and the like.

Note that the aforementioned peak intensity and the like can be analyzed by cutting out the packaging materials 15 and 25 from the electricity storage device 10 . When the packaging materials 15 and 25 are cut out, a sample can be obtained from a portion where the heat-sealable resin layers 38 are not heat-sealed to each other and used for analysis.

4 and 5, the packaging material 25 is formed into a rectangular sheet. The packaging material 15 has a storage portion 16 and a flange portion 17 . The storage part 16 has a substantially rectangular opening 16a on one side and stores the electric storage element 11 therein. The flange portion 17 is formed in an annular shape protruding outward from the peripheral edge of the opening portion 16a.

By heat-sealing the opposing heat-sealable resin layers 38 (see FIG. 6) of the flange portion 17 and the packaging material 25, an annular peripheral seal portion 21 (see FIG. 5) along the periphery of the storage portion 16 is formed. be done. As a result, the storage portion 16 is formed at a predetermined depth from the inner edge of the peripheral edge seal portion 21 and is sealed by the peripheral edge seal portion 21 .

The packaging material 15 is formed by recessing the housing portion 16 to a predetermined depth in the flange portion 17 by sheet molding. At this time, the storage portion 16 is formed in a substantially rectangular shape extending in one direction within a plane perpendicular to the depth direction.

The depth of the storage portion 16 is determined according to the thickness of the barrier layer 36 of the packaging material 15 so that cracks or the like do not occur during molding. In this embodiment, the storage portion 16 is formed to have a depth of 5 mm to 10 mm with respect to the barrier layer 36 having a thickness of 40 μm. At this time, each corner R in a plane perpendicular to the depth direction of the storage portion 16 is formed to be approximately 3 mm, for example, and each corner R in a plane parallel to the depth direction is formed to be approximately 1.5 mm, for example. By increasing the thickness of the barrier layer 36, the depth of the storage section 16 can be formed to, for example, 5 mm to 30 mm.

The power storage device 10 is arranged with the depth direction (Y direction) of the storage portion 16 in the front-rear direction of the electric vehicle 1 . In addition, the longitudinal direction (X direction, first direction) in a plane perpendicular to the depth direction of the storage portion 16 is arranged in the left-right direction of the electric vehicle 1, and the short direction (Z direction, second direction) is arranged in the electric vehicle. 1 height direction. That is, the X direction orthogonal to the depth direction of the storage portion 16 is arranged in the lateral direction of the electric vehicle 1, and the Z direction orthogonal to the depth direction and the X direction of the storage portion 16 is arranged in the height direction of the electric vehicle 1. be done.

Since the storage portion 16 is formed by sheet molding, it is difficult to increase the depth. On the other hand, the storage portion 16 can easily make the lengths Ax and Az in two orthogonal directions within a plane perpendicular to the depth direction larger than the length Ay in the depth direction. Therefore, by arranging the depth direction (Y direction) of the storage section 16 in the front-rear direction of the electric vehicle 1, a plurality of power storage devices 10 can be installed in the electric vehicle 1 without being stacked to supply desired electric power. can be done. Therefore, it is possible to prevent damage to the exterior member 20 due to the weight applied when stacking, and improve the reliability of the power storage device 10 .

In addition, when the electrolyte is an electrolytic solution, when the power storage devices 10 are stacked in the depth direction (Y direction) of the housing portion 16, the packaging material 25 is bent by the weight, and the electrolytic solution is pushed out to the periphery. Therefore, the electrolyte between the positive electrode plate and the negative electrode plate in the central portion is insufficient, and the energy density of the electricity storage device 10 is lowered. Therefore, it is possible to arrange the depth direction (Y direction) of the storage portion 16 in the front-rear direction and prevent the energy density of the electric storage device 10 containing the electrolytic solution from decreasing.

In addition, since the lateral direction (Z direction) in the plane perpendicular to the depth direction of the storage portion 16 is arranged in the height direction, the height of the power storage device 10 is reduced and the comfort of the electric vehicle 1 is improved. be able to. At this time, since the storage part 16 extends long in the X direction and the length Ax in the X direction is larger than the length Az in the Z direction, the height can be suppressed and the power storage device 10 with a large capacity can be obtained.

The X-direction length Ax of the housing portion 16 is formed to be 2 to 30 times the Z-direction length Az. If the length Ax is less than twice the length Az, the capacity of the electricity storage device 10 will be small. Therefore, the length Ax can be formed to be at least twice the length Az, and the capacity of the electric storage device 10 can be increased. Also, if the length Ax exceeds 30 times the length Az, the packaging material 15 cannot be easily molded, resulting in a reduced yield. For this reason, the length Ax can be formed to be 30 times or less the length Az, and the yield when molding the packaging material 15 can be improved.

Also, the peripheral edge seal portion 21 extending in the X direction projects in the Z direction during heat sealing as indicated by a dashed line 21 ′, and is bent after the heat sealing to overlap the peripheral wall of the storage portion 16 . Thereby, the height of the electric storage device 10 can be made smaller.

At this time, the flow direction (MD) of the packaging materials 15 and 25 made up of laminates is arranged in the Z direction (perpendicular to the X direction). If the laminate is folded parallel to the flow direction, the possibility of cracks in the metal foil and pinholes in the resin film increases. Since the direction of flow of the packaging materials 15 and 25 is orthogonal to the X direction, cracks and pinholes in the exterior member 20 can be suppressed when the peripheral seal portion 21 extending in the X direction is bent.

The machine direction (MD) of the packaging materials 15 , 25 corresponds to the rolling direction (RD) of the metal foil (such as aluminum alloy foil) of the barrier layer 36 . The TD of the wrapping material 15, 25 corresponds to the TD of the metal foil. The rolling direction (RD) of the metal foil can be determined by the rolling pattern.

In addition, a plurality of cross sections of the heat-fusible resin layer 38 of the packaging materials 15 and 25 were observed with an electron microscope to confirm a sea-island structure. The direction parallel to the cross section where the average of is maximum can be determined as the MD. When the MD of the packaging materials 15 and 25 cannot be specified by the rolling pattern of the metal foil, the MD can be specified by this method.

Specifically, the cross section in the length direction of the heat-fusible resin layer 38 is changed at an angle of 10 degrees from the direction parallel to the cross section in the length direction, and the direction perpendicular to the cross section in the length direction is changed. Each cross section (10 cross sections in total) is observed with an electron microscope to confirm the sea-island structure. Next, for each island on each cross section, the diameter d of the island is measured by the linear distance connecting both ends in the direction perpendicular to the thickness direction of the heat-fusible resin layer 38 . Next, for each cross section, the average diameter d of the 20 largest islands is calculated. Then, the MD is determined as the direction parallel to the cross section where the average diameter d of the islands is the largest.

The electrode terminals 12 and 13 extend in the Z direction and protrude from the peripheral seal portions 21 facing in the X direction. Therefore, the height of the power storage device 10 can be made lower. In addition, when the electrode terminals 12 and 13 are close to each other, the temperature rise in the vicinity of the electrode terminals 12 and 13 increases, so the power storage device 10 is likely to deteriorate over time. Therefore, by arranging the electrode terminals 12 and the electrode terminals 13 apart from each other in the X direction, it is possible to suppress aging deterioration of the electricity storage device 10 .

The electricity storage device 10 is manufactured by performing a packaging step of packaging the electricity storage element 11 with the exterior member 20 after the step of preparing the molded exterior member 20 . Moreover, a folding process is provided after the packaging process, if necessary.

In the forming process for forming the exterior member 20, the roll-shaped laminated body is cut to a predetermined length, and the housing portion 16 is recessed in the flange portion 17 by cold forming to form the packaging material 15. As shown in FIG. At this time, the packaging materials 15 and 25 are formed by arranging the flow direction (MD) of the roll-shaped laminate in the Z direction. The exterior member 20 may be prepared by a molding process, or the exterior member 20 may be prepared by obtaining a molded exterior member 20 .

In the packaging process, the electrode terminals 12 and 13 are arranged on the flange portion 17, the electric storage element 11 is accommodated in the storage portion 16, and the storage portion 16 is filled with an electrolytic solution. Next, the packaging material 25 is heat-sealed to the flange portion 17 of the packaging material 15 to form a peripheral seal portion 21 along the periphery of the storage portion 16 to seal the storage portion 16 . Thereby, the electric storage element 11 is wrapped by the exterior member 20 .

In the folding step, the peripheral edge seal portion 21 extending in the X direction perpendicular to the flow direction of the laminate is folded and placed on the peripheral wall of the storage portion 16 .

In FIG. 3 described above, the electricity storage device pack 5 is formed by arranging a plurality of electricity storage devices 10 side by side in the Y direction, and is installed in the electric vehicle 1 in one stage in the height direction. A plurality of power storage device packs 5 may be arranged in the X direction or the Y direction and installed in the electric vehicle 1 .

The Z-direction length Bz of the power storage device pack 5 is substantially the same as the Z-direction length Az of the housing portion 16 of the power storage device 10 . The length Bx of the power storage device pack 5 in the X direction is substantially the same as the length of the power storage device 10 in the X direction. Moreover, since the electric storage devices 10 are arranged side by side in the Y direction, the length By of the electric storage device pack 5 in the Y direction is larger than the length Bz in the Z direction.

When the electric vehicle 1 is a sedan type or a compact car type, the height (the length Bz in the Z direction) of the power storage device pack 5 is formed to be 100 mm or less, for example. If the electric vehicle 1 is of the SUV type or the one-box type, the height of the power storage device pack 5 (the length Bz in the Z direction) is set to 150 mm or less, for example.

According to this embodiment, the power storage device 10 is arranged such that the depth direction (Y direction) of the storage portion 16 of the exterior member 20 is in the front-rear direction of the electric vehicle 1 . Also, the X direction (first direction) orthogonal to the depth direction of the storage portion 16 is arranged in the lateral direction of the electric vehicle 1 . The Z direction (second direction) orthogonal to the depth direction and the X direction of the storage portion 16 is arranged in the height direction of the electric vehicle 1 . That is, the X direction (first direction) and Z direction (second direction) that are orthogonal to each other in the plane perpendicular to the depth direction of the storage portion 16 are arranged in the lateral direction and the height direction of the electric vehicle 1, respectively.

Accordingly, it is possible to install a plurality of power storage devices 10 in the electric vehicle 1 without stacking them to supply desired electric power. Therefore, it is possible to prevent damage to the exterior member 20 due to the weight applied when stacking, and improve the reliability of the power storage device 10 . Further, when the electric storage device 10 contains an electrolytic solution, it is possible to prevent the energy density of the electric storage device 10 from decreasing by arranging the storage portion 16 in the depth direction (Y direction) in the front-rear direction.

In addition, since the lateral direction (Z direction) in the plane perpendicular to the depth direction of the storage portion 16 is arranged in the height direction, the length Ax in the X direction of the storage portion 16 is longer than the length Az in the Z direction. big. As a result, the height of the power storage device 10 can be reduced to improve the comfort of the electric vehicle 1, and the power storage device 10 with a large capacity can be obtained.

In addition, since the length Ax of the storage portion 16 in the X direction is 2 to 30 times the length Az in the Z direction, the power storage device 10 having a large capacity can be obtained and the yield of the exterior member 20 can be improved. .

In addition, since the peripheral edge seal portion 21 extending in the X direction is folded and overlapped on the peripheral wall of the storage portion 16, the height of the electric storage device 10 can be further reduced.

In addition, since the flow direction of the packaging materials 15 and 25 is orthogonal to the X direction, it is possible to suppress the occurrence of cracks and pinholes in the exterior member 20 when the peripheral seal portion 21 extending in the X direction is bent.

Moreover, since the electrode terminals 12 and the electrode terminals 13 protrude from the peripheral seal portion 21 extending in the Z direction, the height of the electric storage device 10 can be further reduced.

In addition, since the electrode terminals 12 and the electrode terminals 13 protrude from the peripheral seal portions 21 facing each other in the X direction, aging deterioration of the electricity storage device 10 can be suppressed.

Further, the electricity storage device pack 5 (electricity storage device assembly) is formed by arranging the electricity storage devices 10 side by side in the depth direction (Y direction) of the storage section 16, and the length By of the electricity storage device pack 5 in the Y direction is is greater than the length Bz of . This makes it possible to reduce the height of the power storage device pack 5 and supply desired power.

In addition, since the power storage device pack 5 is installed in one stage in the height direction of the electric vehicle 1, the comfort of the electric vehicle 1 can be improved.

<Second embodiment>
Next, FIGS. 11 and 12 show an exploded perspective view and a side cross-sectional view of the electricity storage device 10 of the second embodiment. For convenience of explanation, the same parts as those of the first embodiment shown in FIGS. 1 to 6 are given the same reference numerals. This embodiment differs from the first embodiment in the shape of the packaging material 25, and the other parts are the same as those in the first embodiment.

The packaging material 25 has a housing portion 26 and a flange portion 27 like the packaging material 15 . The storage part 26 has a substantially rectangular opening 26a on one side. The storage element 11 is accommodated in the storage portion 16 of the packaging material 15 and the storage portion 26 of the packaging material 25 . The flange portion 27 is formed in an annular shape protruding from the peripheral edge of the opening portion 26a to the outer peripheral side.

By heat-sealing the heat-sealable resin layer 38 (see FIG. 6) of the flange portion 17 and the flange portion 27, the annular peripheral edge seal portion 21 along the periphery of the storage portion 16 and the storage portion 26 is formed. As a result, the storage portion 16 and the storage portion 26 formed at a predetermined depth from the inner edge of the peripheral seal portion 21 are sealed by the peripheral seal portion 21 .

Also, the peripheral edge seal portion 21 extending in the X direction projects in the Z direction as indicated by a dashed line 21' when heat-sealed, and is bent after heat-sealing to overlap the peripheral wall of the storage portion 16 or the storage portion 26.

The power storage device 10 is arranged with the depth direction (Y direction) of the storage portions 16 and 26 in the front-rear direction of the electric vehicle 1 . In addition, the longitudinal direction (X direction) in the plane perpendicular to the depth direction of the storage portions 16 and 26 is arranged in the left-right direction of the electric vehicle 1, and the short direction (Z direction) is arranged in the height direction of the electric vehicle 1. placed.

Thereby, the same effects as those of the first embodiment can be obtained. In addition, since the packaging material 15 and the packaging material 25 are provided with the storage portion 16 and the storage portion 26, respectively, the volume of the storage element 11 can be increased and the capacity of the storage device 10 can be increased. Therefore, the number of power storage devices 10 forming the power storage device pack 5 (see FIG. 3) can be reduced, and the number of man-hours for manufacturing the power storage device pack 5 can be reduced.

As shown in FIG. 13 , the power storage device 10 may be covered with protective covers 8 and 9 . The protective covers 8 and 9 are formed by injection molding into a bottomed cylindrical shape having an opening on one side and a rectangular cross section. Also, the outer shape of the protective cover 9 is formed smaller than the opening of the protective cover 8 .

The protective cover 9 is bent along the peripheral wall of the peripheral seal portion 21 protruding from the outer member 20 , and the protective cover 8 is fitted over the protective cover 9 along the peripheral seal portion 21 . As a result, the peripheral seal portion 21 is bent at a position away from the peripheral edges of the openings 16a, 26a (see FIG. 11) of the storage portions 16, 26. As shown in FIG. Therefore, it is possible to reduce the occurrence of cracks and pinholes due to bending of the peripheral edge seal portion 21 .

FIG. 14 shows an electric storage device 10 covered with protective covers 8 and 9 having shapes different from those in FIG. The protective covers 8 and 9 are formed in substantially the same shape by injection molding, and are formed in the shape of a bottomed cylinder having an opening on one side. The electric storage device 10 does not have a folding step, and the protective covers 8 and 9 are fixed in a state in which the peripheral seal portion 21 protruding to the peripheral portion of the exterior member 20 is sandwiched between the peripheral walls of the protective covers 8 and 9 . This protects the peripheral seal portion 21 . Since the bending process is omitted, the occurrence of cracks and pinholes due to bending of the peripheral edge seal portion 21 can be reduced.

Note that the exterior member 20 of the electric storage device 10 of the first embodiment may also be covered with similar protective covers 8 and 9 .

<Third Embodiment>
Next, FIG. 15 shows an exploded perspective view of the electricity storage device 10 of the third embodiment. For convenience of explanation, the same parts as those of the second embodiment shown in FIGS. 11 and 12 are given the same reference numerals. In this embodiment, the packaging material 15 and the packaging material 25 are formed from a single member. Other parts are the same as in the second embodiment.

The exterior member 20 is integrally formed with the packaging material 15 having the storage portion 16 and the packaging material 25 having the storage portion 26 continuously in the Z direction. The flange portion 17 of the packaging material 15 and the flange portion 27 of the packaging material 25 are formed flush with each other through the folding line 20a.

After storing power storage element 11 in storage portion 16 or storage portion 26, exterior member 20 is folded along folding line 20a extending in the X direction. Then, the opposing flange portions 17 and 27 are heat-sealed to form the peripheral seal portion 21 .

According to this embodiment, the same effects as those of the second embodiment can be obtained. Moreover, since the packaging material 15 and the packaging material 25 are formed of a single member, the number of parts of the electricity storage device 10 can be reduced.

In this embodiment, the openings 16a, 26a may be close to each other and the fold line 20a may be provided along the peripheries of the openings 16a, 26a. Thereby, the lower surface of the electrical storage device 10 can be formed flat. Therefore, the adhesion between the installation surface on which the electricity storage device 10 is installed and the electricity storage device 10 is increased, and the heat dissipation property of the electricity storage device 10 can be improved.

Note that the packaging material 15 and the packaging material 25 of the first and second embodiments may be formed by a single member that is continuously provided via the fold line at the lower end.

<Fourth Embodiment>
Next, FIG. 16 shows a top view of the electric vehicle 1 of the fourth embodiment. For convenience of explanation, the same parts as those of the first embodiment shown in FIGS. 1 to 6 are given the same reference numerals. This embodiment differs from the first embodiment in the arrangement of the electric storage device pack 5 . Other parts are the same as in the first embodiment.

The power storage device pack 5 is installed under the floor of the vehicle body of the electric vehicle 1 , and the side-by-side direction of the power storage devices 10 is arranged in the lateral direction of the electric vehicle 1 . As a result, the power storage device 10 is arranged so that the depth direction (Y direction) of the storage portion 16 (see FIG. 4 ) is aligned with the left-right direction of the electric vehicle 1 . In addition, the longitudinal direction (X direction, first direction) in a plane perpendicular to the depth direction of the storage portion 16 is arranged in the left-right direction of the electric vehicle 1, and the short direction (Z direction, second direction) is arranged in the electric vehicle. 1 height direction. That is, the X direction orthogonal to the depth direction of the storage portion 16 is arranged in the front-rear direction of the electric vehicle 1, and the Z direction orthogonal to the depth direction and the X direction of the storage portion 16 is arranged in the height direction of the electric vehicle 1. be done.

Accordingly, it is possible to install a plurality of power storage devices 10 in the electric vehicle 1 without stacking them to supply desired electric power. Therefore, effects similar to those of the first embodiment can be obtained. Also, the air taken inside through the front grill when the electric vehicle 1 is running circulates rearward and contacts each power storage device 10 of the power storage device pack 5 . Therefore, the power storage device 10 can be cooled.

Note that the power storage device 10 of the second embodiment or the third embodiment may be installed in the electric vehicle 1 and the side-by-side arrangement direction of the power storage device 10 may be arranged in the lateral direction of the electric vehicle 1 .

In the first to fourth embodiments, the cross-sectional shape of the storage portions 16 and 26 perpendicular to the Y direction is substantially rectangular, but other shapes such as oval, elliptical, and polygonal may also be used.

Moreover, although the electric storage device 10 that supplies electric power to the drive motor 3 is composed of a secondary battery, it may be a capacitor (electrolytic capacitor, electric double layer capacitor, lithium ion capacitor, etc.).

Examples and comparative examples formed to evaluate the characteristics of the packaging materials 15 and 25 forming the exterior container 6 of the electricity storage device 10 will be described below.

The packaging material 15 of Example 1 is formed by the laminated structure shown in FIG. 9 described above. The substrate layer 34 is a laminate of a biaxially stretched polyethylene terephthalate film with a thickness of 5 μm and a biaxially stretched nylon film with a thickness of 20 μm. The biaxially stretched polyethylene terephthalate film and the biaxially stretched nylon film are bonded together with an adhesive (thickness 1 μm) using a resin composition containing a modified thermoplastic resin graft-modified with an unsaturated carboxylic acid derivative component. there is

The barrier layer 36 was formed of aluminum foil (JIS H4160:1994 A8021H-O) with a thickness of 40 μm, and provided with corrosion-resistant coatings 36a and 36b with a thickness of 20 nm on both sides. The heat-fusible resin layer 38 was formed from an unstretched polypropylene film having a thickness of 40 μm. The polypropylene film is formed by laminating random polypropylene (5 μm thick), block polypropylene (30 μm thick), and random polypropylene (5 μm thick).

The adhesive layer 35 between the base material layer 34 and the barrier layer 36 was formed with a thickness of 3 μm using a two-component urethane adhesive (polyol compound and aromatic isocyanate compound). The adhesive layer 37 between the barrier layer 36 and the heat-fusible resin layer 38 was formed of an adhesive (having a thickness of 3 μm after curing) composed of an acid-modified polyolefin resin having a carboxyl group and a polyfunctional isocyanate compound.

A method of forming the packaging material 15 is as follows. First, a treatment liquid was applied to both surfaces of the aluminum foil forming the barrier layer 36 and dried to form the corrosion-resistant films 36a and 36b. The treatment liquid contains 100 parts by mass of cerium oxide and 20 parts by mass of an inorganic phosphorus compound (sodium phosphate), and contains water as a solvent. The solid content concentration of the treatment liquid is about 10% by mass. Drying of the treatment liquid was performed by heating for about 3 to 6 seconds at a temperature at which the surface temperature of the barrier layer 36 was about 190 to 230.degree.

Next, the biaxially stretched nylon film side of the base material layer 34 and the barrier layer 36 were laminated via the adhesive layer 35 by a dry lamination method, and cured by an aging treatment to form a laminate A. Next, an adhesive for forming the adhesive layer 37 was applied on the barrier layer 36 and dried, and the laminated film for forming the heat-fusible resin layer 38 was superimposed and passed between two heated rolls to be bonded. . Next, the obtained laminate was subjected to an aging treatment to obtain the packaging material 15 .

As a result, the laminated structure of the packaging material 15 of Example 1 is biaxially oriented polyethylene terephthalate film (5 μm)/adhesive (1 μm)/biaxially oriented nylon film (20 μm)/adhesive layer (3 μm)/acid-resistant film on both sides A barrier layer (40 μm) provided with a flexible film (thickness: 20 nm)/adhesive layer (3 μm)/unstretched polypropylene film (40 μm).

The packaging material 15 of Example 2 is formed by the laminated structure shown in FIG. 9 described above. The heat-fusible resin layer 38 was formed from an unstretched polypropylene film having a thickness of 80 μm. The polypropylene film is formed by laminating random polypropylene (thickness 10 μm), block polypropylene (thickness 60 μm), and random polypropylene (thickness 10 μm). Other layer structures and lamination methods are the same as in the first embodiment.

As a result, the laminated structure of the packaging material 15 of Example 2 is biaxially oriented polyethylene terephthalate film (5 μm)/adhesive (1 μm)/biaxially oriented nylon film (20 μm)/adhesive layer (3 μm)/acid-resistant film on both sides A barrier layer (40 μm) provided with a flexible film (thickness: 20 nm)/adhesive layer (3 μm)/unstretched polypropylene film (80 μm).

[Comparative Example 1]
The packaging material 15 of Comparative Example 1 is formed by the layered structure shown in FIG. 9 described above. The base material layer 34 was formed of a biaxially oriented nylon film with a thickness of 25 μm. The barrier layer 36 was formed of an aluminum foil (JIS H4160:1994 A8021H-O) with a thickness of 40 μm, and provided with corrosion-resistant coatings 36a and 36b containing chromium with a thickness of 20 nm on both sides.

The heat-fusible resin layer 38 was formed from an unstretched polypropylene film with a thickness of 30 μm and a random polypropylene film with a thickness of 50 μm. The polypropylene film is formed by laminating random polypropylene (4 μm thick), block polypropylene (22 μm thick), and random polypropylene (4 μm thick).

The adhesive layer 35 between the base material layer 34 and the barrier layer 36 was formed with a thickness of 3 μm using a two-component urethane adhesive (polyol compound and aromatic isocyanate compound). The adhesive layer 37 between the barrier layer 36 and the heat-fusible resin layer 38 is formed of an adhesive (having a thickness of 3 μm after curing) consisting of an amorphous polyolefin resin having a carboxyl group and a polyfunctional isocyanate compound. .

A method of forming the packaging material 15 is as follows. First, a treatment liquid was applied to both surfaces of the aluminum foil forming the barrier layer 36 and dried to form the corrosion-resistant films 36a and 36b. The treatment liquid contains 43 parts by weight of aminated phenolic polymer, 16 parts by weight of chromium fluoride, and 13 parts by weight of phosphoric acid with respect to 100 parts by weight of water. Drying of the treatment liquid was performed by heating for about 3 to 6 seconds at a temperature at which the surface temperature of the barrier layer 36 was about 190 to 230.degree.

Next, the biaxially stretched nylon film forming the base material layer 34 and the barrier layer 36 were laminated via the adhesive layer 35 by the dry lamination method, and aging treatment was performed to form a laminate A. Next, an adhesive for forming an adhesive layer 37 was applied on the barrier layer 36 and dried, and unstretched polypropylene films were overlapped and passed between two heated rolls to be bonded. Further, random polypropylene was extruded from thereon and subjected to an aging treatment to obtain a packaging material 15 .

As a result, the laminated structure of the packaging material 15 of Comparative Example 1 is biaxially stretched nylon film (25 μm)/adhesive layer (3 μm)/barrier layer (40 μm) provided with a corrosion-resistant film (thickness of 20 nm) on both sides/adhesive layer (3 μm)/unstretched polypropylene film (30 μm)/random polypropylene (50 μm).

[Comparative Example 2]
In the packaging material 15 of Comparative Example 2, the thickness of the random polypropylene forming the heat-fusible resin layer 38 is different from that of Comparative Example 1 and is 20 μm. The other layer structure and lamination method are the same as in Comparative Example 1.

As a result, the laminated structure of the packaging material 15 of Comparative Example 2 is biaxially stretched nylon film (25 μm)/adhesive layer (3 μm)/barrier layer (40 μm) provided with a corrosion-resistant film (thickness of 20 nm) on both sides/adhesive layer (3 μm)/unstretched polypropylene film (30 μm)/random polypropylene (20 μm).

[Comparative Example 3]
The packaging material 15 of Comparative Example 3 is formed in the same manner as in Example 1, and the concentration of phosphoric acid in the treatment liquid during the formation of the corrosion-resistant coatings 36a and 36b is about half that of Example 1 (mass ratio). The rest of the lamination structure and formation method are the same as those of the first embodiment.

[Comparative Example 4]
The packaging material 15 of Comparative Example 4 is formed in the same manner as in Example 1, and the concentration of phosphoric acid in the treatment liquid during the formation of the corrosion-resistant films 36a and 36b is about 1.5 times that of Example 1 (mass ratio). The rest of the lamination structure and formation method are the same as those of the first embodiment.

Analysis of the corrosion-resistant film 36a and an evaluation test of the adhesion of the barrier layer 36 were conducted for each of the above Examples and Comparative Examples. Table 1 shows analysis results and evaluation test results.

<Time-of-Flight Secondary Ion Mass Spectrometry>
Analysis of the corrosion-resistant film 36a was performed using time-of-flight secondary ion mass spectrometry. The specimen for analysis was peeled away between the barrier layer 36 and the adhesive layer 37 to expose the barrier layer 36 . At this time, the peeling was performed physically without using water, an organic solvent, an acid aqueous solution, an alkaline aqueous solution, or the like. The adhesive layer 37 remaining on the peeled off barrier layer 36 was removed by etching with Ar-GCIB.

Thus, the corrosion-resistant film 36a on the barrier layer 36 was analyzed using time-of-flight secondary ion mass spectrometry. The details of the measurement apparatus and measurement conditions for time-of-flight secondary ion mass spectrometry are as follows.

Measuring device: Time-of-flight secondary ion mass spectrometer TOF. manufactured by ION-TOF. SIMS5
(Measurement condition)
Primary ions: Double charged ions of bismuth clusters (Bi ₃ ⁺⁺ )
Primary ion acceleration voltage: 30 kV
Mass range (m/z): 0-1500
Measurement range: 100 μm×100 μm
Number of scans: 16 scans/cycle
Number of pixels (one side): 256 pixels
Etching ion: Ar gas cluster ion beam (Ar-GCIB)
Etching ion acceleration voltage: 5.0 kV

Table 1 shows peak intensities P _CePO4 , P _PO2 and P _PO3 derived from CePO ₄ ⁻ , PO ₂ ⁻ and PO ₃ ⁻ obtained by time-of-flight secondary ion mass spectrometry. Also, the ratio P PO2/ _CePO4 of the peak intensity P _PO2 to the peak intensity P _CePO4 and the ratio P _{PO3/ CePO4} of the peak intensity P _PO3 to the peak intensity P CePO4 are shown.

Incidentally, in Comparative Examples ¹ and 2, chromium was used in the treatment liquid for chemical conversion treatment, and _cerium was not used.

<Evaluation of Adhesion>
Adhesion between the barrier layer 36 and the heat-fusible resin layer 38 was evaluated by measuring peel strength (unit: N/15 mm). A test piece was formed by cutting the packaging material 15 into a size of 15 mm in TD (Transverse Direction) and 100 mm in MD (Machine Direction).

The initial adhesion was determined by measuring the peel strength of the prepared test piece by a tensile test. The adhesion after being immersed in the electrolyte was determined by measuring the peel strength of the test piece after being immersed in the electrolyte by a tensile test as described below.

For immersion in the electrolytic solution, the test piece and the electrolytic solution were placed in a glass bottle, the entire test piece was immersed in the electrolytic solution, and the glass bottle was sealed with a lid. The electrolytic solution was prepared by adding lithium hexafluorophosphate (concentration in solution: 1×10 ³ mol/m ³ ) to a mixed solution of ethylene carbonate:diethyl carbonate:dimethyl carbonate=1:1:1 by volume.

Then, the sealed glass bottle was placed in an oven set at 85° C. and allowed to stand for 24 hours. Next, the glass bottle was taken out of the oven, the test piece taken out of the glass bottle was washed with water, and the moisture on the surface was wiped off with a towel. Thereafter, the peel strength was measured within 10 minutes after wiping off moisture on the surface of the test piece with a towel.

The tensile test was performed using a tensile tester (AGS-XPlus manufactured by Shimadzu Corporation). The barrier layer 36 and the heat-fusible resin layer 38 of the test piece were peeled about 20 mm in the length direction, attached to the tester with a distance between the gauge lines of 50 mm, and rotated 180° by the tester at a speed of 50 mm/min. The specimen was pulled in the direction The peel strength of the test piece was defined as the strength when the distance between the gauge lines reached 57 mm. When the barrier layer 36 and the heat-fusible resin layer 38 are separated, the adhesive layer 37 adheres to one or both of the barrier layer 36 and the heat-fusible resin layer 38 .

Table 1 shows the peel strength (N / 15 mm) indicating the initial adhesion, the peel strength (N / 15 mm) indicating the adhesion after immersion in the electrolyte, and the retention rate (%) of the peel strength after immersion in the electrolyte against the initial value. showing. The retention rate of peel strength is obtained by taking the initial peel strength as 100% and deriving the ratio of the peel strength after being immersed in the electrolytic solution.

As is clear from Table 1, in the packaging materials 15 of Examples 1 and 2, CePO The ratio P PO3 / _CePO4 of the peak intensity P _PO3 derived from PO ₃ ⁻ to the peak intensity P _CePO4 derived from ₄ ⁻ is in the range of 80-120.

At this time, although the packaging material 15 of Examples 1 and 2 has the corrosion-resistant film 36 a on the surface of the barrier layer 36 , the barrier layer 36 and the heat-fusible resin layer 38 are separated after being immersed in the electrolytic solution. It can be seen that the adhesion between the layers is excellent.

Further, in the packaging materials 15 of Examples 1 and 2, when the corrosion-resistant film 36a provided on the surface of the barrier layer 36 was analyzed using time-of-flight secondary ion mass spectrometry, a peak derived from CePO ₄ ⁻ The ratio P _{PO2 /CePO4} of the peak intensity P _PO2 derived from PO ₂ ⁻ to the intensity P _CePO4 is in the range of 90-150. At this time, it can be seen that the adhesion between the barrier layer 36 and the heat-fusible resin layer 38 is excellent after being immersed in the electrolytic solution.

INDUSTRIAL APPLICABILITY According to the present invention, it can be widely used in electric vehicles equipped with power storage devices.

Reference Signs List 1 electric vehicle 2 wheel 3 drive motor 5 power storage device pack 6 exterior container 10 power storage device 11 power storage element 12, 13 electrode terminals 15, 25 packaging material 16, 26 storage section 16a, 26a opening 17, 27 flange section 20 exterior member 20a Folding line 21 Peripheral sealing portion 32 Surface coating layer 34 Base material layer 35 Adhesive layer 36 Barrier layer 36a, 36b Corrosion-resistant film 37 Adhesive layer 38 Heat-fusible resin layer

Claims (22)

An electricity storage device mounted as a drive source on an electric vehicle, wherein an electricity storage element is enclosed in an exterior member composed of a laminate comprising at least a substrate layer, a barrier layer, and a heat-fusible resin layer in this order, and the exterior member comprises: A member has a peripheral edge seal portion and a storage portion formed at a predetermined depth from an inner edge of the peripheral edge seal portion to store the storage element, and the depth direction of the storage portion and the depth of the storage portion The first direction perpendicular to the direction is arranged in the front-rear direction or the left-right direction of the electric vehicle, and the depth direction of the storage section and the second direction perpendicular to the first direction are arranged in the height direction of the electric vehicle. ,
At least one surface of the barrier layer is provided with a corrosion-resistant film, and when the corrosion-resistant film is analyzed using time-of-flight secondary ion mass spectrometry, the peak intensity P _CePO4 derived ^from _CePO4- The ratio P _PO3/CePO4 of the peak intensity P _{PO3 derived from PO 3 − is} in the range of 80 to 120, or the ratio P PO2/ _CePO4 of the peak intensity P _PO2 derived from PO ₂ ⁻ to ^the peak intensity _{P CePO4} is is in the range of 90 to 150,
The electricity storage device , wherein the peripheral edge seal portion extending in the first direction is folded to overlap the peripheral wall of the storage portion . 2. The electricity storage device according to claim 1, wherein the storage portion has a length in the first direction greater than a length in the second direction. 3. The electricity storage device according to claim 2, wherein the length of the storage portion in the first direction is 2 to 30 times the length in the second direction. The electricity storage device according to any one of claims 1 to 3, wherein the flow direction of the exterior member is orthogonal to the first direction. 2. The storage element has a first electrode terminal and a second electrode terminal, and the first electrode terminal and the second electrode terminal protrude from the peripheral seal portion extending in the second direction. The electricity storage device according to any one of - Claim 4 . 6. The electricity storage device according to claim 5 , wherein the first electrode terminal and the second electrode terminal respectively protrude from the peripheral seal portions facing in the first direction. The electricity storage device according to any one of claims 1 to 6, wherein the corrosion-resistant film is provided on the surface of the barrier layer on the heat-fusible resin layer side. 8. The electricity storage device according to claim 7 , wherein the corrosion-resistant film and the heat-fusible resin layer are laminated via an adhesive layer. 9. The electricity storage device according to claim 8 , wherein the resin forming the adhesive layer has a polyolefin skeleton. 10. The electricity storage device according to claim 8 , wherein the adhesive layer contains acid-modified polyolefin. 11. The electricity storage device according to claim 10 , wherein the acid-modified polyolefin contained in the adhesive layer is maleic anhydride-modified polypropylene, and the heat-fusible resin layer contains polypropylene. 12. The electricity storage device according to claim 8 , wherein a peak derived from maleic anhydride is detected when the adhesive layer is analyzed by infrared spectroscopy. The adhesive layer is a cured product of a resin composition containing at least one selected from the group consisting of compounds having an isocyanate group, compounds having an oxazoline group, and compounds having an epoxy group. The electricity storage device according to any one of claims 8 to 12 . The adhesive layer is a cured product of a resin composition containing a curing agent having at least one selected from the group consisting of oxygen atoms, heterocycles, C═N bonds, and C—O—C bonds. The electricity storage device according to any one of claims 8 to 12 . The electricity storage device according to any one of claims 8 to 12 , wherein the adhesive layer contains at least one selected from the group consisting of urethane resins, ester resins, and epoxy resins. The electricity storage device according to any one of claims 1 to 15 , wherein the barrier layer is made of aluminum foil. The electricity storage device according to any one of claims 1 to 16 , wherein the resin forming the heat-fusible resin layer contains a polyolefin skeleton. A power storage device assembly in which a plurality of the power storage devices according to any one of claims 1 to 17 are arranged side by side in the depth direction of the storage portion and stored in an outer container and mounted on an electric vehicle, wherein a plurality of the power storage devices An electricity storage device assembly, wherein a length in a direction in which the electricity storage devices are arranged side by side is longer than a length in the second direction. 19. The power storage device assembly according to claim 18 , a drive motor to which power is supplied from the power storage device assembly, and wheels driven by the drive motor, wherein the power storage device assembly is mounted on the bottom of the vehicle body in the height direction. An electric vehicle characterized by being arranged in one stage at. In a method for manufacturing an electric storage device to be mounted as a drive source in an electric vehicle, an exterior member provided with a storage section is prepared from a laminate comprising at least a substrate layer, a barrier layer, and a heat-fusible resin layer in this order. and a step of storing the electricity storage element in the storage portion and packaging it with the exterior member, wherein the depth direction of the storage portion and a first direction orthogonal to the depth direction of the storage portion are the electric vehicle. In addition to being arranged in the front-back direction or the left-right direction, the depth direction of the storage portion and the second direction orthogonal to the first direction are arranged in the height direction of the electric vehicle, and the length of the storage portion in the first direction is greater than the length in the second direction,
At least one surface of the barrier layer is provided with a corrosion-resistant film, and when the corrosion-resistant film is analyzed using time-of-flight secondary ion mass spectrometry, the peak intensity P _CePO4 derived ^from _CePO4- The ratio P _PO3/CePO4 of the peak intensity P _{PO3 derived from PO 3 − is} in the range of 80 to 120, or the ratio P PO2/ _CePO4 of the peak intensity P _PO2 derived from PO ₂ ⁻ to ^the peak intensity _{P CePO4} is is in the range of 90 to 150,
The step of wrapping with the exterior member includes forming a peripheral edge seal portion for sealing the exterior member by heat sealing of the heat-fusible resin layer on the periphery of the exterior member, and the peripheral edge extending in the second direction. A method of manufacturing an electricity storage device, comprising folding a seal portion and placing it on the peripheral wall of the storage portion . 21. The method of manufacturing an electricity storage device according to claim 20 , wherein the length of the storage portion in the first direction is 2 to 30 times the length in the second direction. 22. The method of manufacturing an electricity storage device according to claim 20, wherein the first direction is perpendicular to the flow direction of the exterior member.

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