JP2018198212A - Packaging material for electrochemical cell - Google Patents

Abstract

To provide a packaging material for an electrochemical cell, excellent in durability and hardly causing delamination.SOLUTION: In a packaging material for an electrochemical cell, a base material layer 112 comprises a resin obtained by mixing one or two or more selected from copolymer polyester which includes polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, or ethylene terephthalate, as main constituents of a repeating unit, and copolymer polyester which includes butylene terephthalate, as main constituents of a repeating unit, and an adhesive layer 113 comprises at least one resin selected from among polyester, acid modified polyolefin, metal modified polyolefin, a mixed resin of polyester and acid modified polyolefin, a mixed resin of polyester and metal modified polyolefin, copolymer polyamide, and a mixed resin of polyester and copolymer polyamide.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a packaging material for an electrochemical cell that forms a packaging body for an electrochemical cell.

  A conventional packaging material for an electrochemical cell is disclosed in Patent Document 1. This packaging material is formed by a laminate in which a base material layer made of an outermost resin film, a barrier layer made of a metal foil, and an innermost thermal adhesive layer are laminated in order. And the packaging body of an electrochemical cell is formed by heat-sealing a peripheral part with the heat bonding layers facing each other. The package is provided with a space for storing battery elements such as an electrolytic solution and a separator. This space is formed by press-molding a packaging material cut into a rectangular shape.

  The base material layer and the barrier layer are bonded by a dry laminating method. In the dry laminating method, a two-component curable adhesive in which a main agent and a curing agent are mixed at a certain blending ratio is applied to the surface of the metal foil, and then the resin film is bonded together while being pressurized.

JP 2008-288117 A

  However, according to the packaging material, the adhesive for dry lamination has low spreadability after curing. For this reason, it is impossible to follow the extension of the base material layer at the time of press molding, the lamination strength decreases between the base material layer and the barrier layer, pinholes are generated, or the delamination occurs between the base material layer and the barrier layer. There was a problem of lamination. Also, the adhesive for dry lamination has low durability under high humidity conditions. For this reason, there has been a problem that the adhesive is yellowed or is deteriorated due to heat deterioration due to heat at the time of heat sealing.

  Then, in view of the said problem, this invention aims at providing the packaging material for electrochemical cells which is excellent in durability and does not generate | occur | produce a delamination easily.

  In order to achieve the above object, the present invention provides a base material layer made of a resin film arranged on the outermost layer, a heat adhesive layer made of a thermoadhesive resin arranged on the innermost layer, the base material layer, and the heat A packaging material for an electrochemical cell configured by laminating a barrier layer made of a metal foil and an adhesive layer that bonds the base material layer and the barrier layer between the adhesive layer, The base material layer is a copolymer polyester mainly composed of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, ethylene terephthalate, and a copolymer mainly composed of butylene terephthalate. It is composed of a resin obtained by mixing one or more selected from polymerized polyester, and the adhesive layer is made of polyester. , Acid-modified polyolefin, metal-modified polyolefin, mixed resin of polyester and acid-modified polyolefin, mixed resin of polyester and metal-modified polyolefin, copolymerized polyamide, mixed resin of polyester and copolymerized polyamide It is characterized by being comprised of resin.

  According to this configuration, the adhesive layer is made of polyester, acid-modified polyolefin, metal-modified polyolefin, mixed resin of polyester and acid-modified polyolefin, mixed resin of polyester and metal-modified polyolefin, copolymerized polyamide, mixed of polyester and copolymerized polyamide. It is comprised with at least 1 sort (s) of resin chosen from resin. These resins have excellent spreadability as compared with adhesives for dry lamination, and have high durability even under high humidity conditions. In addition, these resins are not easily deteriorated by heat applied during heat sealing. The base material layer is composed of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, copolymerized polyester mainly composed of ethylene terephthalate, butylene terephthalate mainly composed of repeating units. It is comprised with resin which mixed the 1 type (s) or 2 or more types chosen from copolyester made. These resins are excellent in resistance to electrolytic solution, and whitening or the like hardly occurs due to the adhesion of the electrolytic solution.

  Further, in the packaging material for an electrochemical cell having the above-described configuration, the polyester constituting the adhesive layer may be polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, ethylene terephthalate. It is characterized by comprising a resin in which one or two or more types selected from copolymerized polyesters mainly composed of units and copolymerized polyesters mainly composed of butylene terephthalate as repeating units are mixed. According to this configuration, since the adhesive layer is made of the same polyester as the base material layer, the lamination strength between the adhesive layer and the base material layer is improved.

  Further, the present invention is characterized in that the adhesive layer is multilayered with different types of resins.

  Further, the present invention is characterized in that the base material layer and the adhesive layer are laminated on the barrier layer by a thermal laminating method in the packaging material for an electrochemical cell having the above configuration.

  Moreover, the present invention is characterized in that the base material layer and the adhesive layer are laminated on the barrier layer by a sand lamination method in the electrochemical cell packaging material having the above-described configuration.

  The present invention is also characterized in that, in the electrochemical cell packaging material having the above-described structure, the barrier layer is subjected to chemical conversion treatment on at least one surface of the metal foil.

  According to the present invention, the adhesive layer is polyester, acid-modified polyolefin, metal-modified polyolefin, mixed resin of polyester and acid-modified polyolefin, mixed resin of polyester and metal-modified polyolefin, copolymer polyamide, mixture of polyester and copolymer polyamide. The base layer is composed of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, ethylene terephthalate as a main repeating unit. It is comprised by the resin which mixed the 1 type (s) or 2 or more types chosen from the copolyester which made the repeating unit the main unit of repeating polyester and butylene terephthalate. As a result, the adhesive layer has excellent spreadability as compared with an adhesive for dry lamination, and has high durability even under high humidity conditions. In addition, the adhesive layer is unlikely to be thermally degraded by heat applied during heat sealing. For this reason, generation | occurrence | production of delamination can be prevented by suppressing the fall of the lamination intensity | strength between a base material layer and a barrier layer. Moreover, the base material layer is excellent in resistance to electrolytic solution, and whitening or the like hardly occurs with respect to adhesion of the electrolytic solution.

The perspective view of the lithium ion battery which concerns on embodiment of this invention AA line sectional view in FIG. Schematic sectional view showing a layer structure of a packaging material according to an embodiment of the present invention

  Hereinafter, a packaging material for an electrochemical cell according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a lithium ion battery 121 of the present embodiment, and FIG. 2 is a cross-sectional view taken along line AA in FIG.

  The lithium ion battery 121 is configured by housing a lithium ion battery main body 122 containing an electrolytic solution in the package 120. The package 120 includes a storage portion 120a that stores the lithium ion battery main body 122 and a sheet-like lid portion 120b that covers the storage portion 120a.

  The package 120 has a thermal bonding portion 120c at the periphery where the storage portion 120a and the lid portion 120b overlap each other, and the inside is sealed. At this time, the positive electrode tab 123a and the negative electrode tab 123b connected to the lithium ion battery main body 122 extend to the outside while being sandwiched by the storage portion 120a and the lid portion 120b with a tab film (not shown) interposed in the thermal bonding portion 120. ing.

  The lithium ion battery main body 122 is configured by a cell including a positive electrode made of a positive electrode active material and a positive electrode current collector, a negative electrode made of a negative electrode active material and a negative electrode current collector, and an electrolyte filled between the positive electrode and the negative electrode. The The cell is formed by laminating a plurality of positive electrode plates from which a positive electrode current collector extends and negative electrode plates from which a negative electrode current collector extends. A plurality of positive plates and negative plates are alternately stacked via separators. The plurality of stacked positive electrode current collectors and negative electrode current collectors are overlapped and connected to a single positive electrode tab 123a and negative electrode tab 123b, respectively.

  FIG. 3 is a schematic cross-sectional view showing a layer structure of the packaging material 110 forming the storage portion 120a and the lid portion 120b. The packaging material 110 is formed by sequentially laminating a base material layer 112, a barrier layer 114, and a thermal adhesive layer 116. Composed. The base material layer 112 and the barrier layer 114 are bonded via an adhesive layer 113, and the barrier layer 114 and the thermal adhesive layer 116 are bonded via an acid-modified polyolefin layer 115. The both surfaces of the barrier layer 114 are subjected to chemical conversion treatment, and the interlayer lamination strength between the barrier layer 114 and the acid-modified polyolefin layer 115 and between the barrier layer 114 and the adhesive layer 113 is increased.

  As shown in FIG. 2, the storage part 120a is produced by press-molding a packaging material 110 cut into a rectangular shape. In the molding process, the base material layer 112 side of the packaging material 110 is placed in contact with the female molding die, and then the male molding die is used to form a predetermined molding depth from the thermal bonding layer 116 side. Cold forming. The storage portion 120 and the lid portion 120b are thermally bonded at the opposing heat bonding layer 116.

  The base material layer 112 is made of a permeable resin film and imparts high puncture resistance (pinhole resistance), insulation, workability, and the like to the package 120. Moreover, it is necessary to have the extensibility which can endure the press at the time of emboss molding.

  The base material layer 112 can be used by arbitrarily selecting a polyester resin. As polyester, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, copolymer polyester mainly composed of ethylene terephthalate, copolymer polyester mainly composed of butylene terephthalate The resin which mixed 1 type, or 2 or more types chosen from these can be used. These resins are excellent in resistance to electrolytic solution, and whitening or the like hardly occurs due to the adhesion of the electrolytic solution. Further, the base material layer 112 may be multilayered with different resin types. Moreover, it is preferable that the base material layer 112 performs a biaxial stretching process. Thereby, the resin film is oriented and crystallized, and the heat resistance and electrolysis resistance of the base material layer 112 can be improved.

  The copolymer polyester mainly composed of ethylene terephthalate is a copolymer polyester polymerized with ethylene isophthalate mainly composed of ethylene terephthalate (hereinafter abbreviated as polyethylene (terephthalate / isophthalate)), polyethylene (Terephthalate / isophthalate), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate), polyethylene (terephthalate / decandi) Carboxylate).

  The copolymer polyester mainly composed of butylene terephthalate as a repeating unit is a copolymer polyester polymerized with butylene isophthalate having butylene terephthalate as a repeating unit (hereinafter abbreviated as polybutylene (terephthalate / isophthalate)). , Polybutylene (terephthalate / adipate), polybutylene (terephthalate / sebacate), polybutylene (terephthalate / decanedicarboxylate), and polybutylene naphthalate.

  Moreover, the polyester resin which consists of a mixture which blended bisphenol A polycarbonate to these may be sufficient. The above-mentioned polyester resin composition is preferably polyethylene terephthalate, polyethylene (terephthalate / isophthalate), polyethylene (terephthalate / adipate), polyethylene (terephthalate / decanedicarboxylate), polybutylene (terephthalate / isophthalate). ), Polybutylene (terephthalate / adipate), polybutylene (terephthalate / decane dicarboxylate), polybutylene naphthalate, polycyclohexanedimethylene terephthalate and polycarbonate.

  The barrier layer 114 is made of a metal foil and prevents water vapor from entering the lithium ion battery 121 from the outside. In addition, aluminum having a thickness of 15 μm or more is used in order to stabilize pinholes of the barrier layer 114 and processability (pouching, embossing formability) and to have pinhole resistance.

  In addition, when making the package 120 into an embossed type, 0.3 to 9.0 weight% of iron is contained in the aluminum used as the barrier layer 114. By setting the iron content to 0.7 to 2.0% by weight, the malleability is better than that of aluminum not containing iron, and the package 120 is less likely to be pinholes due to bending. In addition, the side wall can be easily formed when the packaging material 110 is embossed. In addition, when the iron content of aluminum is less than 0.3% by weight, effects such as prevention of pinholes and improvement of embossing moldability are not recognized. Moreover, when the iron content of aluminum exceeds 9.0% by weight, the flexibility as aluminum is hindered, and the bag-making property as a packaging material is deteriorated.

  Moreover, the flexibility, the strength of the waist, and the hardness of aluminum manufactured by cold rolling of the barrier layer 114 change under annealing (so-called annealing treatment) conditions. The aluminum of the barrier layer 114 is preferably aluminum that has been annealed and tends to be softer than a hard-treated product that has not been annealed.

  The chemical conversion treatment is formed on the surface of the barrier layer 114 by a chromium system or a non-chromium system. Examples of the chromium-based chemical conversion treatment include chromate chromate treatment, phosphoric acid chromate treatment, and coating type chromate treatment. Examples of the non-chromium chemical conversion treatment include chemical conversion treatment of zirconium, titanium, zinc phosphate and the like. At this time, the coating-type chemical conversion treatment is more desirable because it can be continuously treated and a water washing step is unnecessary and the processing cost can be reduced. In particular, it is most desirable to treat with a treatment liquid containing an aminated phenol polymer, a trivalent chromium compound, and a phosphorus compound.

  Also, as a chemical conversion treatment method, phosphoric acid is coated with a metal oxide such as aluminum oxide, titanium oxide, cerium oxide, tin oxide or the like and fine particles of barium sulfate are coated and baked at 150 ° C. or higher to form a barrier. There is a method of providing a corrosion-resistant layer (not shown) on the surface of the layer 114.

  Further, on the corrosion-resistant layer, polyethyleneimine, an ionic polymer complex composed of a polymer having polyethyleneimine and carboxylic acid, a primary amine-grafted acrylic resin in which a primary amine is grafted on an acrylic main skeleton, polyallylamine or a derivative thereof A resin layer (not shown) in which a cationic polymer composed of at least one selected from aminophenol is crosslinked with a crosslinking agent may be formed. As the crosslinking agent, at least one crosslinking agent selected from the group consisting of a compound having any functional group of isocyanate group, glycidyl group, carboxyl group and oxazoline group and / or a silane coupling agent can be used.

  In addition, the chemical conversion treatment may be formed by selecting a known liquid coating method such as a bar coating method, a roll coating method, a gravure coating method, or a dipping method as the processing solution. Further, it is desirable that the surface of the barrier layer 114 is preliminarily treated by a known degreasing method such as an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, and an acid activation method before the chemical conversion treatment. Thereby, the function of chemical conversion treatment can be expressed to the maximum and maintained for a long time.

  The adhesive layer 113 is a layer that adheres the base material layer 112 and the barrier layer 114. The adhesive layer 113 is selected from polyester, acid-modified polyolefin, metal-modified polyolefin, mixed resin of polyester and acid-modified polyolefin, mixed resin of polyester and metal-modified polyolefin, copolymer polyamide, and mixed resin of polyester and copolymer polyamide. And at least one kind of resin. Polyester is polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, copolymer polyester mainly composed of ethylene terephthalate, copolymer polyester mainly composed of butylene terephthalate, It consists of resin which mixed 1 type, or 2 or more types chosen from. As the polyester used in the adhesive layer 113, the polyester constituting the base material layer 112 described above can be used. When the adhesive layer 113 includes the same polyester as the base material layer 112, the lamination strength between the base material layer 112 and the adhesive layer 113 is high.

Further, the copolyamide is not particularly limited, and for example, [NH (CH ₂ ) ₅ CO], [NH (CH ₂ ) ₆ NHCO (CH ₂ ) ₄ CO], [NH (CH ₂ ) ₆ NHCO (CH ₂ ) ₈ CO], [NH (CH ₂ ) ₁₀ CO], [NH (CH ₂ ) ₁₁ CO], crystalline and amorphous having at least two kinds selected as structural units Mention may be made of copolymerized polyamides.

  Specifically, nylon 6I, nylon 6T, nylon 6IT, nylon 6I6T containing structural units derived from aliphatic polyamides such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, terephthalic acid and / or isophthalic acid. (I represents isophthalic acid, T represents terephthalic acid) and the like, hexamethylenediamine-isophthalic acid-terephthalic acid copolymerized polyamide, polymetaxylylene adipamide (MXD6) -containing polyamide, polyaminomethylcyclohexyl adipa Polyamide (PACM6) and other alicyclic polyamides, and polyamides copolymerized with lactam components and isocyanate components such as 4,4'-diphenylmethane-diisocyanate, copolymerized polyamides and polyesters and polyalkylene ether glycols Polyester amide copolymer and polyether ester amide copolymer is a copolymer of and the like and mixtures thereof and copolymers.

  These resins have excellent spreadability as compared with an adhesive for dry lamination, have excellent durability even under high humidity conditions, and hardly yellow. Moreover, it is hard to be thermally deteriorated with respect to heat applied during heat sealing. For this reason, it is possible to prevent the occurrence of delamination by suppressing a decrease in the lamination strength between the base material layer and the 112 barrier layer 114. Thereby, it can prevent that the external appearance of the lithium ion battery 121 is impaired. In addition, even if the lithium ion battery 121 is leaked, it is possible to prevent a decrease in insulation on the surface of the package 120.

  The base material layer 112 can be laminated on the barrier layer 114 by a thermal lamination method, a sand lamination method, or a combination of a thermal lamination method and a sand lamination method. In the thermal laminating method, a multilayer film in which the base material layer 112 and the adhesive layer 113 are laminated is prepared in advance, the barrier layer 114 is superimposed on the adhesive layer 113, and the adhesive layer is bonded to the base material layer 112 and the barrier layer 114 by a heating roll. Thermocompression bonding is performed while sandwiching 113. Further, in the thermal laminating method, a multilayer film in which the barrier layer 114 and the adhesive layer 113 are laminated is prepared in advance, and the base material layer 112 and the barrier layer are overlapped with the heated barrier layer 114 and the adhesive layer 113 by overlapping the base material layer 112. Thermocompression bonding may be performed while the adhesive layer 113 is sandwiched between the layers 114. As a result, the adhesive layer 113 melts and adheres to the barrier layer 114 at the interface between the contacting adhesive layer 113 and the barrier layer 114.

  In addition, the multilayer film in which the base material layer 112 and the adhesive layer 113 prepared in advance in the thermal laminating method are laminated is obtained by melt extrusion or solution coating (liquid coating) of the resin constituting the adhesive layer 113 on the resin film constituting the base material layer 112. After being laminated by coating) and dried, it is formed by baking at a temperature equal to or higher than the melting point of the resin constituting the adhesive layer 113. By performing the baking, the adhesive strength between the barrier layer 114 and the adhesive layer 113 is improved. Similarly, for the multilayer film in which the barrier layer 114 and the adhesive layer 113 prepared in advance in the thermal laminating method are laminated, the resin constituting the adhesive layer 113 is melt-extruded or solution coated on the metal foil constituting the barrier layer 114. After being laminated and dried, baking is preferably performed at a temperature equal to or higher than the melting point of the resin constituting the adhesive layer 113.

  Further, the adhesive layer 113 may be multilayered with different resin types. For example, when the adhesive layer 113 is composed of two different resins, two different types of resins constituting the adhesive layer 113 are melt-extruded and laminated on the resin film constituting the base material layer 112. At this time, the resin arranged on the base layer 112 side is selected as a resin excellent in adhesion to the base layer 112, and the resin arranged on the barrier layer 114 side is selected as a resin excellent in adhesion to a metal. It is preferable. Thereby, the lamination intensity | strength of the base material layer 112 and the barrier layer 114 becomes strong. Specifically, it is preferable that an acid-modified polyolefin, metal-modified polyolefin, mixed resin of polyester and acid-modified polyolefin, or a resin containing a copolyester is provided on the barrier layer 114 side.

  In the sand laminating method, a resin that forms the base layer 112 is bonded to the barrier layer 114 by melting and extruding a resin to be the adhesive layer 113 on the upper surface of the barrier layer 114. At this time, the resin film is bonded and temporarily bonded, and then heated again to perform the main bonding. In the sand lamination method, the adhesive layer 113 may be multilayered with different resin types. In this case, a multilayer film in which the base material layer 112 and the adhesive layer 113 are laminated is prepared in advance, and the resin constituting the adhesive layer 113 is melt-extruded on the upper surface of the barrier layer 114 and laminated by the multilayer resin film and the thermal lamination method. To do. As a result, the adhesive layer 113 constituting the multilayer film and the adhesive layer 113 laminated on the upper surface of the barrier layer 114 are bonded to form a two-layer adhesive layer 113.

  In addition, a multilayer film in which the barrier layer 114 and the adhesive layer 113 are laminated is prepared in advance, and the resin constituting the adhesive layer 113 is melt-extruded on the base material layer 112 to laminate the barrier layer 114 and the base material layer 112. May be. As a result, an adhesive layer 113 composed of two different resin species is formed between the barrier layer 114 and the base material layer 112.

  In addition, it is preferable to heat-process the packaging material 110 laminated | stacked by the thermal lamination method or the sand lamination method above the melting | fusing point of resin which comprises the contact bonding layer 113. FIG. Thereby, a part of the adhesive layer 113 is melted, and the lamination strength between the adhesive layer 113 and the base material layer 112 and the lamination strength between the adhesive layer 113 and the barrier layer 114 are improved. As a heat treatment method, there are a hot roll contact method, a hot air method, infrared heating, near infrared heating, dielectric heating, thermal resistance heating, and the like. Further, the heat treatment may be performed after the packaging material 110 is press-molded. Thereby, the pinhole generated in the press molding can be repaired.

  The thermal adhesive layer 116 is disposed on the innermost layer of the packaging material 110 and is made of a thermal adhesive resin that melts by heat and fuses the opposing packaging materials 110 to each other. The resin type differs depending on whether or not a tab film is interposed between the thermal adhesive layer 116 and the positive electrode tab 123a or the negative electrode tab 123b. When a tab film is interposed, a film made of a simple substance or a mixture of olefinic resins may be used. In the case where no tab film is interposed, an acid-modified olefin graft-modified with an unsaturated carboxylic acid may be used.

  Also, polypropylene is preferably used as the thermal bonding layer 116. In addition, a film composed of a single layer or a multilayer of linear low density polyethylene and medium density polyethylene can be used. Moreover, the film which consists of a single layer or a multilayer which consists of a mixed resin of linear low density polyethylene and medium density polyethylene can also be used.

  Further, when each type of polypropylene is used for the thermal bonding layer 116, for example, each type such as random propylene, homopropylene, block propylene and the like can be used. Linear low-density polyethylene and medium-density polyethylene include a low-crystalline ethylene-butene copolymer, a low-crystalline propylene-butene copolymer, and a terpolymer composed of a three-component copolymer of ethylene, butene, and propylene. It may be added. Moreover, you may add antiblocking agents (AB agent), such as a silica, a zeolite, and an acrylic resin bead, and a fatty acid amide type slip agent to these resin.

  The acid-modified polyolefin layer 115 is a resin layer that stably bonds the barrier layer 114 and the thermal adhesive layer 116, and acid-modified polypropylene is preferably used. In addition, the acid-modified polyolefin layer 115 needs to be appropriately selected and used depending on the resin type used for the thermal bonding layer 116. For this reason, when using an acid-modified polyolefin other than acid-modified polypropylene, a polyolefin graft-modified with an unsaturated carboxylic acid, a copolymer of ethylene and acrylic acid graft-modified with an unsaturated carboxylic acid, or a graft modification with an unsaturated carboxylic acid Copolymer of propylene and acrylic acid, copolymer of ethylene and methacrylic acid graft-modified with unsaturated carboxylic acid, copolymer of propylene and methacrylic acid graft-modified with unsaturated carboxylic acid, unsaturated carboxylic acid There are metal cross-linked polyolefins grafted with acid. Further, 5% or more of a butene component, an ethylene-propylene-butene copolymer, an amorphous ethylene-propylene copolymer, a propylene-α-olefin copolymer, etc. may be added to these resins as necessary. Good.

When using acid-modified polypropylene,
(1) A homotype having a bigat softening point of 115 ° C or higher and a melting point of 150 ° C or higher (2) A copolymer of ethylene-propylene having a bigat softening point of 105 ° C or higher and a melting point of 130 ° C or higher (random copolymer type)
(3) A simple substance or a mixture obtained by acid-modified polymerization using an unsaturated carboxylic acid having a melting point of 110 ° C. or higher can be used.

  According to this embodiment, the adhesive layer 113 includes polyester, acid-modified polyolefin, metal-modified polyolefin, mixed resin of polyester and acid-modified polyolefin, mixed resin of polyester and metal-modified polyolefin, copolymer polyamide, polyester and copolymer polyamide, And at least one kind of resin selected from these mixed resins. Thereby, these resins are excellent in spreadability as compared with the adhesive for dry lamination, and are excellent in durability even under high humidity conditions. Moreover, it is hard to be thermally deteriorated with respect to heat applied during heat sealing. For this reason, it is possible to prevent the occurrence of delamination by suppressing a decrease in the lamination strength between the base material layer 112 and the barrier layer 114. Further, the base material layer 112 is a copolymerized polyester mainly composed of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, ethylene terephthalate, and butylene terephthalate as a main repeating unit. It is comprised with resin which mixed the 1 type (s) or 2 or more types chosen from the copolyester made. These resins are excellent in electrolytic solution resistance. For this reason, the base material layer 112 is unlikely to be whitened or the like due to the adhesion of the electrolytic solution.

  Further, the polyester used for the adhesive layer 113 is a copolymerized polyester mainly composed of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, ethylene terephthalate, and repeating units of butylene terephthalate. The adhesive layer 113 is made of the same polyester as the base material layer 112, and is composed of a resin in which one or two or more types selected from the copolyesters selected from the above are mixed. The lamination strength with the layer 112 is improved.

  In addition, by layering the adhesive layer 113 with different types of resins, a resin having excellent adhesiveness to the base material layer 112 is disposed on the layer in contact with the base material layer 112, and the barrier layer 114 side is attached to the metal foil. In addition, a resin having excellent adhesiveness can be disposed. Thereby, the lamination strength of the base material layer 112 and the barrier layer 114 is improved via the adhesive layer 113.

  Moreover, the productivity of the packaging material 110 can be increased by laminating the base material layer 112 and the adhesive layer 113 by a thermal lamination method or a sand lamination method.

  Moreover, the barrier layer 114 can raise the lamination intensity | strength with respect to resin of the surface which performed the chemical conversion treatment by performing a chemical conversion treatment to at least one surface of metal foil.

  In the present embodiment, different layers may be interposed between the layers. Moreover, although the lithium ion battery 121 is described, an electrochemical cell body other than the lithium ion battery body 122 may be packaged with a package 120 made of the packaging material 110 to produce an electric cell other than the lithium ion battery 121. .

  For example, the electrochemical cell includes a nickel metal hydride battery, a nickel cadmium battery, a lithium metal primary battery or secondary battery, a chemical battery such as a lithium polymer battery, an electric double layer capacitor, a capacitor, and an electrolytic capacitor in addition to a lithium ion battery. Here, the electrochemical cell body is a positive electrode composed of a positive electrode active material and a positive electrode current collector before enclosing packaging material, a negative electrode composed of a negative electrode active material and a negative electrode current collector, and an electrolyte filled between the positive electrode and the negative electrode. And all electric device elements that generate electric energy, such as a cell (power storage unit) including electrode terminals connected to a positive electrode and a negative electrode in the cell.

  Next, the action and effect of the present invention will be specifically described using examples and comparative examples. In this example, the base material layer constituting the packaging material for an electrochemical cell is laminated on the upper surface of the barrier layer by any one of the thermal laminating method, the sand laminating method, and the dry laminating method. Was evaluated.

[Sample preparation of packaging materials for electrochemical cells]
The packaging material 110 for electrochemical cells according to Examples 1 to 7 is subjected to chemical conversion treatment on both surfaces of aluminum (thickness 40 μm), and a base material layer 112 (thickness 5 μm) and an adhesive layer 113 (thickness) are formed on one chemical conversion treatment surface. Is laminated by a thermal laminating method.

  The packaging material 110 for electrochemical cells according to Examples 8 to 11 was subjected to chemical conversion treatment on both surfaces of aluminum (thickness 40 μm), and one of the chemical conversion treatment surfaces was melt-extruded with a resin constituting the adhesive layer 113 to form a base material layer. A multilayer film in which 112 and an adhesive layer 113 were laminated was laminated by a sand lamination method. Thereby, the adhesive layer 113 is made into two layers.

  In addition, in the packaging materials for electrochemical cells according to Examples 1 to 11 and Comparative Examples 1 to 3, the other chemical conversion treatment surface of aluminum is in a state where acid-modified polypropylene (thickness 25 μm) and polypropylene (thickness 25 μm) are melted. Coextruded and laminated.

In the chemical conversion treatment, a treatment liquid composed of a phenol resin, a chromium fluoride compound, and phosphoric acid was applied as a treatment liquid by a roll coating method, and baked under conditions where the film temperature was 180 ° C. or higher. Here, the coating amount of chromium was 10 mg / m ² (dry weight). Moreover, the packaging material for electrochemical cells according to Examples 1 to 10 and Comparative Examples 1 and 3 was cooled once, and then heated to 190 ° C., and heated for 5 seconds while maintaining the temperature.

[Example 1]
The packaging material 110 for an electrochemical cell according to Example 1 is a co-polymerized polymer with ethylene isophthalate having polyethylene terephthalate (hereinafter abbreviated as PET) biaxially stretched on a base layer 112 and ethylene terephthalate as a main repeating unit in an adhesive layer. Polymer polyester (hereinafter abbreviated as PETI) was used.

[Example 2]
The packaging material 110 for an electrochemical cell according to Example 2 is a copolymer polyester (hereinafter referred to as PBTI) that is polymerized with butylene isophthalate with PET as a biaxially stretched base material layer 112 and butylene terephthalate as a main repeating unit in the adhesive layer 113. Abbreviated).

[Example 3]
As the packaging material 110 for an electrochemical cell according to Example 3, a biaxially stretched PET was used for the base material layer 112, and a resin made of a polyether ester amide copolymer was used for the adhesive layer 113.

[Example 4]
As the packaging material 110 for an electrochemical cell according to Example 4, a biaxially stretched PET was used for the base material layer 112, and a mixed resin of PETI, PBTI, and acid-modified polypropylene (hereinafter abbreviated as PPa) was used for the adhesive layer 113.

[Example 5]
As the packaging material 110 for an electrochemical cell according to Example 5, polycarbonate (hereinafter abbreviated as PC) biaxially stretched on the base material layer 112 and a mixed resin of PETI and PC were used for the adhesive layer 113.

[Example 6]
The packaging material 110 for an electrochemical cell according to Example 6 is polybutylene terephthalate (hereinafter abbreviated as PBT) biaxially stretched on the base layer 112, butylene terephthalate as a main unit of repeating unit of butylene terephthalate in the adhesive layer 113. A resin made of a copolymer polyester that polymerizes with the polymer was used.

[Example 7]
As the packaging material 110 for an electrochemical cell according to Example 7, a biaxially stretched PET was used for the base material layer 112, and a mixed resin of PETI and PPa, PPa, was used for the adhesive layer 113. The adhesive layer 113 is multilayered, a mixed resin of PETI and PPa is disposed on the base material layer 112 side, and PPa is disposed on the barrier layer 114 side.

  In addition, the packaging material 110 for an electrochemical cell according to Example 7 is a multilayer film in which a mixed resin (10 μm) of PETI and PPa is laminated on one surface of PET (thickness 5 μm) which is a base material layer 112; A multilayer film obtained by laminating PPa serving as the adhesive layer 113 on the upper surface of aluminum as the barrier layer 114 by liquid coating at a thickness of 3 μm and drying at 180 ° C. was laminated by thermal lamination via PPa.

[Example 8]
As the packaging material 110 for an electrochemical cell according to Example 8, PET biaxially stretched on the base material layer 112 and a mixed resin of PETI and PBTI were used for the adhesive layer 113. In Example 8, a mixed resin of PETI and PBTI was melt-extruded to a thickness of 20 μm on PET (thickness 5 μm) and laminated by aluminum and sand lamination.

[Example 9]
The electrochemical cell packaging material 110 according to Example 9 used biaxially stretched PET for the base material layer 112, and PBTI and PPa for the adhesive layer 113. The adhesive layer 113 is multi-layered, and the adhesive layer 113 has PBTI disposed on the base material layer 112 side and PPa disposed on the barrier layer 114 side. Moreover, in the packaging material 110 for electrochemical cells according to Example 9, a biaxially stretched PET (thickness 5 μ), PBTI, and (20 μm) multilayer film, and a multilayer in which PPa is melt extruded at a thickness of 10 μm on the upper surface of aluminum. The film was laminated by a sand lamination method.

[Example 10]
The packaging material 110 for an electrochemical cell according to Example 10 is a polyethylene naphthalate (hereinafter abbreviated as PEN) biaxially stretched on a base layer 112, and PETI, PETI and hexamethylenediamine-isophthalic acid-terephthalic acid on an adhesive layer 113. A mixed resin of copolyamide and a polyesteramide copolymer were used. The adhesive layer 113 is multilayered, and the adhesive layer 113 has PETI on the base material layer 112 side and a polyesteramide copolymer on the barrier layer 114 side. In Example 10, a multilayer film of a biaxially stretched PEN (thickness 5 μ), PETI (thickness 5 μ), mixed resin (20 μm) of PETI and hexamethylenediamine-isophthalic acid-terephthalic acid copolymer polyamide, aluminum A multilayer film in which a polyesteramide copolymer resin was melt-extruded with a thickness of 15 μm was laminated on the upper surface by a sand lamination method.

[Example 11]
As the packaging material 110 for an electrochemical cell according to Example 11, a biaxially stretched PET was used for the base material layer 112, and a mixed resin of PETI and PPa, PPa, was used for the adhesive layer 113. The adhesive layer 113 is multilayered, and the adhesive layer 113 has a mixed resin of PETI and PPa arranged on the base material layer 112 side, and PPa arranged on the barrier layer 114 side. In Example 11, a multilayer film in which a mixed resin (10 μm) of PETI and PPa is laminated on PET (thickness 5 μm) and a multilayer film in which PPa is melt-extruded at a thickness of 10 μm on the upper surface of aluminum are obtained by sand lamination. Laminated.

[Comparative Example 1]
The packaging material for an electrochemical cell according to Comparative Example 1 was subjected to the above chemical conversion treatment on both surfaces of aluminum (thickness 40 μm), and a two-component curable polyurethane adhesive (thickness 4 μm) was applied to one chemical conversion treatment surface. A biaxially stretched PET film and a multilayer film (thickness 12 μm) made of PETI were laminated by a dry laminating method.

[Comparative Example 2]
The packaging material for electrochemical cells according to Comparative Example 2 was subjected to chemical conversion treatment on both sides of aluminum (thickness 40 μm), and a biaxially stretched PET film (thickness 25 μm) was directly laminated on one chemical conversion treatment surface by thermal lamination. did.

[Comparative Example 3]
The packaging material for an electrochemical cell according to Comparative Example 3 was subjected to chemical conversion treatment on both sides of aluminum (thickness 40 μm), and the acid-modified polypropylene melted on one chemical conversion treatment surface was extruded at a thickness of 10 μm to form a PET film (thickness 25 μm). ) Was laminated by a sand laminating method.

[Evaluation of durability]
Durability evaluation is as follows. After the packaging materials according to Examples 1 to 11 and Comparative Examples 1 to 3 were stored at a temperature of 65 ° C. and a humidity of 95% for 1000 hours, the adhesive layer turned yellow from the base material layer side. It was observed visually. Moreover, the lamination strength (lamination strength) of the base material layer and the barrier layer was measured before and after storage, and the reduction rate of the lamination strength was calculated. The results are shown in Table 1.

[Evaluation of moldability]
The moldability was evaluated by cutting the packaging materials according to Examples 1 to 11 and Comparative Examples 1 to 80 mm × 120 mm, then forming a 35 mm × 50 mm diameter mold (female mold) and a corresponding mold (Male type) was cold-molded to a depth of 6.0 mm at 0.1 MPa, and it was visually observed whether or not pinholes were generated on the surface of the packaging material on the base material layer side. In addition, the molded packaging material is heat sealed (190 ° C., 10 seconds, surface pressure 2 MPa) and stored for 1000 hours at a temperature of 65 ° C. and a humidity of 95%, and then between the substrate layer and the barrier layer. It was visually observed whether or not lamination occurred. In addition, it pressed by 10 each about each packaging material which concerns on Examples 1-11 and Comparative Examples 1-3, and the incidence rate of the pinhole and the occurrence rate of delamination (delamination) were computed. The results are shown in Table 1. In addition, press molding was performed after confirming whether wrinkles were generated on the surface of the packaging material before press molding.

  As shown in Table 1, in the packaging materials according to Examples 1 to 11, no yellowing was observed (◯), and the reduction rate of the laminar strength was 20% or less, compared with Comparative Examples 1 to 3. It was low. In addition, the occurrence of pinholes and delamination was not confirmed. Moreover, the packaging material laminated | stacked by the dry lamination method of the comparative example 1 had the high incidence rate of a wrinkle compared with other packaging materials.

  INDUSTRIAL APPLICABILITY The present invention can be used as a package for packaging chemical batteries such as nickel metal hydride batteries, nickel cadmium batteries, lithium metal primary batteries or secondary batteries, lithium polymer batteries, and electric double layer capacitors, capacitors, and electrolytic capacitors.

DESCRIPTION OF SYMBOLS 110 Packaging material 112 Base material layer 113 Adhesion layer 114 Barrier layer 115 Acid-modified polyolefin layer 116 Thermal adhesion layer 120 Package 120a Storage part 120b Lid part 121 Lithium ion battery 122 Lithium ion battery main body 123a Positive electrode tab 123b Negative electrode tab

Claims (5)

A base material layer made of a resin film arranged on the outermost layer, a heat adhesive layer made of a thermoadhesive resin arranged on the innermost layer, and a metal foil arranged between the base material layer and the heat adhesive layer A packaging material for an electrochemical cell comprising: a barrier layer comprising: an adhesive layer that bonds the base material layer and the barrier layer;
The base material layer is a copolymer polyester mainly composed of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, ethylene terephthalate, and mainly composed of butylene terephthalate. It is composed of a resin obtained by mixing one or more selected from copolymerized polyesters,
The adhesive layer is composed of at least one resin selected from metal-modified polyolefin and polyester ,
The polyester is polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, copolymer polyester mainly composed of ethylene terephthalate, copolymer polyester mainly composed of butylene terephthalate and repeat units. A packaging material for electrochemical cells, which is composed of a resin obtained by mixing one or more selected types . The adhesive layer is
Copolyester having ethylene terephthalate as a main repeating unit,
The packaging material for an electrochemical cell according to claim 1, which is a copolymer polyester polymerized with ethylene isophthalate with ethylene terephthalate as a main repeating unit. The adhesive layer is
Copolyester having the repeating unit of butylene terephthalate as the main component,
The packaging material for an electrochemical cell according to claim 1, which is a copolymer polyester polymerized with butylene isophthalate with butylene terephthalate as a main repeating unit. A base material layer made of a resin film arranged on the outermost layer and a heat-adhesive resin arranged on the innermost layer
A thermal adhesive layer, a barrier layer made of a metal foil disposed between the base material layer and the thermal adhesive layer, and
A packaging material for an electrochemical cell comprising a base material layer and an adhesive layer for adhering the barrier layer.
A method for producing a coating material, wherein the base material layer is a copolymerized polyester, butylene, mainly composed of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, ethylene terephthalate. It is composed of a resin in which one or two or more types selected from copolymerized polyesters mainly composed of terephthalate are mixed, and the adhesive layer is at least one resin selected from metal-modified polyolefins and polyesters. A method for producing a packaging material for an electrochemical cell, wherein the base material layer and the adhesive layer are laminated on the barrier layer by a thermal laminating method. A base material layer made of a resin film arranged on the outermost layer and a heat-adhesive resin arranged on the innermost layer
A thermal adhesive layer, a barrier layer made of a metal foil disposed between the base material layer and the thermal adhesive layer, and
A packaging material for an electrochemical cell comprising a base material layer and an adhesive layer for adhering the barrier layer.
A method for producing a coating material, wherein the base material layer is a copolymerized polyester, butylene, mainly composed of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, ethylene terephthalate. It is composed of a resin in which one or two or more types selected from copolymerized polyesters mainly composed of terephthalate are mixed, and the adhesive layer is at least one resin selected from metal-modified polyolefins and polyesters. in the configuration, the manufacturing method of the packaging material for electric cell, wherein the base layer and the adhesive layer is laminated to said barrier layer by a sand lamination method.

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