JP2017073391A - Packaging material for electrochemical cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packaging material for an electrochemical cell, excellent in durability and hardly causing a delamination.SOLUTION: In a packaging material for an electrochemical cell, a base material layer 112 comprises polyamide comprising any one of nylon 6, nylon 66 and nylon 12, or copolyamide, and an adhesive layer 113 comprises at least one resin selected from among copolyamide, acid-modified polyolefin, metal-modified polyolefin, a mixed resin of copolyamide and acid-modified polyolefin, a mixed resin of copolyamide and metal-modified polyolefin, copolyamide and polyester, polyester, a mixed resin of polyester and acid-modified polyolefin, and a mixed resin of polyester and metal-modified polyolefin.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 urethane 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 made of polyamide or copolymer polyamide made of nylon 6, nylon 66, or nylon 12, and the adhesive layer is copolymer polyamide, acid-modified polyolefin, metal-modified polyolefin, copolymer polyamide and acid-modified. Mixed resins of polyolefin, mixed resins of copolymerized polyamide and metal-modified polyolefin, mixed resins of copolymerized polyamide and polyester, polyester, polyester and acid-modified polyolefin Mixed resins of fin, is characterized by being composed of at least one resin selected from the mixed resin, the polyester and the metal-modified polyolefin.

  According to this configuration, the adhesive layer is made of copolymerized polyamide, acid-modified polyolefin, metal-modified polyolefin, mixed resin of copolymerized polyamide and acid-modified polyolefin, mixed resin of copolymerized polyamide and metal-modified polyolefin, copolymerized polyamide and polyester. And a mixed resin of polyester, polyester and acid-modified polyolefin, and a mixed resin of polyester and metal-modified polyolefin. 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.

  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.

  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 made of copolymerized polyamide, acid-modified polyolefin, metal-modified polyolefin, mixed resin of copolymerized polyamide and acid-modified polyolefin, mixed resin of copolymerized polyamide and metal-modified polyolefin, copolymerized polyamide and polyester. , Polyester, mixed resin of polyester and acid-modified polyolefin, mixed resin of polyester and metal-modified polyolefin, and the base material layer is made of nylon 6, nylon 66, nylon 12 or the like. It is composed of any polyamide or copolymer polyamide. 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.

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.

  As the base material layer 112, a polyamide resin film can be arbitrarily selected and used. Nylon 6, nylon 66, or nylon 12 can be used as the polyamide. It can also be formed using a copolymerized polyamide. 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 of the base material layer 112 can be improved.

The copolyamide is not particularly limited. For example, [NH (CH ₂ ) ₅ CO], [NH (CH ₂ ) ₆ NHCO (CH ₂ ) ₄ CO], [NH (CH ₂ ) ₆ Crystalline and amorphous copolymer having at least two kinds selected from NHCO (CH ₂ ) ₈ CO], [NH (CH ₂ ) ₁₀ CO], and [NH (CH ₂ ) ₁₁ CO] as structural units Mention may be made of polyamide.

  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.

  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. Adhesive layer 113 is a copolymerized polyamide, acid-modified polyolefin, metal-modified polyolefin, mixed resin of copolymerized polyamide and acid-modified polyolefin, mixed resin of copolymerized polyamide and metal-modified polyolefin, mixed resin of copolymerized polyamide and polyester, It is composed of at least one resin selected from polyester, a mixed resin of polyester and acid-modified polyolefin, and a mixed resin of polyester and metal-modified polyolefin. As the copolymerized polyamide, the above-described copolymerized polyamide in the base material layer 112 can be used.

  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. When the adhesive layer 113 includes a copolyamide having the same quality as the base material layer 112, the lamination strength between the base material layer 112 and the adhesive layer 113 is high.

  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 polyester resin composition is preferably polyethylene terephthalate, polyethylene (terephthalate / isophthalate), polyethylene (terephthalate / adipate), polyethylene (terephthalate / decane dicarboxylate), polybutylene (terephthalate / isophthalate), polybutylene (terephthalate). / Adipate), polybutylene (terephthalate / decane dicarboxylate), polybutylene naphthalate, polycyclohexanedimethylene terephthalate, polycarbonate.

  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 the present embodiment, the adhesive layer 113 is made of copolymerized polyamide, acid-modified polyolefin, metal-modified polyolefin, mixed resin of copolymerized polyamide and acid-modified polyolefin, mixed resin of copolymerized polyamide and metal-modified polyolefin, copolymerized polyamide, It is comprised with at least 1 sort (s) of resin chosen from mixed resin with polyester, polyester, mixed resin of polyester and acid-modified polyolefin, and mixed resin of polyester and metal-modified polyolefin. 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.

  The base material layer 112 is made of polyamide or copolymer polyamide made of nylon 6, nylon 66, or nylon 12.

  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 lamination strength between the adhesive layer 113 and the base material layer 112 is improved by comprising a resin in which one or two or more types selected from the copolyesters as a main component are mixed.

  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 15 μm) and an adhesive layer 113 are formed on one chemical conversion treatment surface. The laminated multilayer film was laminated by a thermal lamination 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 a state in which acid-modified polypropylene (thickness: 25 μm) and polypropylene (thickness: μm) are melted. Were 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 has a biaxially stretched nylon 6 (thickness 12 μm) as a base layer 112 and a polyamide 6 / terephthalic acid copolymer polyamide (hereinafter abbreviated as nylon 6T) as an adhesive layer 113. And a thickness of 10 μm).

[Example 2]
In the electrochemical cell packaging material 110 according to Example 2, biaxially stretched nylon 12 (thickness: 15 μm) was used for the base material layer 112, and the adhesive layer 113 was not provided.

[Example 3]
The packaging material 110 for an electrochemical cell according to Example 3 has a base material layer 112 with a biaxially stretched copolymer polyamide (thickness 15 μm) and an adhesive layer 113 with a polyetheresteramide copolymer (hereinafter referred to as PEEA). Abbreviated, thickness 5 μm) was used.

[Example 4]
The packaging material 110 for an electrochemical cell according to Example 4 has a biaxially stretched nylon 6 (thickness 15 μm) as a base layer 112 and a copolyamide of nylon 6, isophthalic acid and terephthalic acid (hereinafter referred to as nylon) as an adhesive layer 113. A mixed resin (thickness: 15 μm) of acid-modified polypropylene (hereinafter abbreviated as PPa) was used.

[Example 5]
The packaging material 110 for an electrochemical cell according to Example 5 is made of a biaxially stretched nylon 6 (thickness 5 μm) as a base layer 112, a polyesteramide copolymer (hereinafter abbreviated as PEPA) and ethylene terephthalate as an adhesive layer 113 A mixed resin (thickness: 10 μm) with a copolymer polyester (hereinafter abbreviated as PETI) that is polymerized with ethylene isophthalate was used as the main repeating unit.

[Example 6]
A packaging material 110 for an electrochemical cell according to Example 6 is a biaxially stretched film (thickness 15 μm) made of a mixed resin of nylon 6 and nylon 66 on a base layer 112, and polymetaxylylene adip (hereinafter referred to as an adhesive layer 113). , MXD6) and nylon 6IT mixed resin (thickness 10 μm).

[Example 7]
As the packaging material 110 for an electrochemical cell according to Example 7, nylon 6 biaxially stretched on the base material layer 112, and a multilayer film containing PPA, a mixed resin of PETI and PPa, and PPa for the adhesive layer 113 were used. In the adhesive layer 113, three layers of PEPA, a mixed resin of PETI and PPa, and PPa are laminated in order, PEPA is arranged on the base material layer 112 side, and PPa is arranged on the barrier layer 114 side.

  The packaging material 110 for an electrochemical cell according to Example 7 is a multilayer film in which a mixed resin (10 μm) of PEPA, PETI, and PPa is sequentially laminated on one surface of nylon 6 (thickness 5 μm) as a base layer 112. And 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 with a thickness of 3 μm and drying at 180 ° C., and the multilayer films are subjected to thermal lamination. Laminated.

[Example 8]
In the electrochemical cell packaging material 110 according to Example 8, biaxially stretched nylon 6 was used for the base material layer 112 and PEEA was used for the adhesive layer 113. In Example 7, a multilayer resin film was used in which PEEA was melt-extruded to a thickness of 10 μm and laminated on biaxially stretched nylon 6 (thickness 12 μm). PEEA was melt-extruded at a thickness of 15 μm on the upper surface of aluminum, and a multilayer resin film was laminated by a sand lamination method.

[Example 9]
In the electrochemical cell packaging material 110 according to Example 9, a biaxially stretched nylon 6 and nylon 66 copolymer polyamide was used for the base layer 112, and a nylon 6IT and nylon 12 mixed resin was used for the adhesive layer 113. In Example 9, a multilayer resin film was used in which nylon 12 was melt-extruded to a thickness of 5 μm on a biaxially stretched nylon 6 and nylon 66 copolymer polyamide (thickness 12 μm) and laminated. A mixed resin of nylon 6IT and nylon 12 was melt extruded at a thickness of 15 μm on the upper surface of aluminum, and a multilayer resin film was laminated by a sand lamination method.

[Example 10]
In the packaging material 110 for an electrochemical cell according to Example 10, biaxially stretched nylon 6 was used for the base material layer 112, and a mixed resin of MXD6 and acid-modified polypropylene and acid-modified polypropylene were used for the adhesive layer 113. The adhesive layer 113 is multilayered, the mixed resin is disposed on the base material layer 112 side, and the acid-modified polypropylene is disposed on the barrier layer 114 side. In Example 10, a multilayer resin film made of a biaxially stretched nylon 6 (thickness 12 μm), a mixed resin of nylon 6T and acid-modified polypropylene (thickness 10 μm) was used, and the acid-modified polypropylene was thickened on the upper surface of aluminum. A multilayer resin film was laminated by a sand lamination method by melt extrusion at 15 μm.

[Example 11]
The packaging material 110 for an electrochemical cell according to Example 11 is a biaxially stretched nylon 6 (thickness 5 μm) on a base layer 112, and a polybutylene (terephthalate / isophthalate) copolymer (hereinafter abbreviated as PBTI) on an adhesive layer 113. ), Nylon 6IT and PEEA, and PETI and PBTI. The adhesive layer 113 is multilayered, and a mixed resin of PBTI, nylon 6IT, and PEEA is disposed on the base layer 112 side, and a mixed resin of PETI and PBTI is disposed on the barrier layer 114 side. In Example 11, a multilayer resin film of biaxially stretched nylon 6 (thickness 15 μ) and a mixed resin (thickness 10 μ) of PBTI, nylon 6IT, and PEEA is used, and PETI and PBTI are formed on the upper surface of aluminum. The mixed resin was melt-extruded with a thickness of 15 μm, and a multilayer resin film was laminated by a sand lamination method.

[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 multilayer film composed of biaxially stretched nylon 6 (thickness 12 μm) and nylon 6IT was laminated by a dry laminating method.

[Comparative Example 2]
The packaging material for an electrochemical cell according to Comparative Example 2 is subjected to chemical conversion treatment on both sides of aluminum (thickness 40 μm), and a biaxially stretched nylon 6 film (thickness 15 μm) is directly applied to one chemical conversion treatment surface by a thermal lamination method. Laminated.

[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 melt-modified polypropylene was extruded on one chemical conversion treatment surface with a thickness of 25 μm. A film (thickness 15 μm) was laminated by a sand lamination method.

[Evaluation of durability]
Durability evaluation was 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, and then forming a 35 mm × 50 mm diameter mold (female mold) and a corresponding mold. A mold (male type) was cold-molded to a depth of 6.0 mm at 0.1 MPa, and whether or not pinholes were generated on the surface of the packaging material on the base material layer side was visually observed. 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 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 material 110 according to Examples 1 to 11, no yellowing was observed (◯), and the reduction rate of the laminating 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.

  The present invention packages nickel metal hydride batteries, nickel cadmium batteries, lithium metal primary batteries or secondary batteries, lithium polymer batteries, metal-air batteries, polyvalent cation batteries, and other chemical batteries, electric double layer capacitors, capacitors, and electrolytic capacitors. It can be used as a package.

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 (6)

  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 formed by laminating a barrier layer comprising: an adhesive layer for bonding the base material layer and the barrier layer, wherein the base material layer is nylon 6, nylon 66, It is composed of polyamide or copolymer polyamide made of any of nylon 12, and the adhesive layer is copolymer polyamide, acid-modified polyolefin, metal-modified polyolefin, mixed resin of copolymer polyamide and acid-modified polyolefin, copolymer polyamide and metal Mixed resin with modified polyolefin, mixed resin of copolyamide and polyester, polyester, mixed resin of polyester and acid-modified polyolefin, and polyester Packaging material for electrochemical cell, characterized by being composed of at least one resin mixed resin, selected from the genus modified polyolefin.   The polyester constituting the adhesive 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. The packaging material for an electrochemical cell according to claim 1, comprising a resin obtained by mixing one or more selected from the copolyesters described above.   The packaging material for an electrochemical cell according to claim 1 or 2, wherein the adhesive layer is multilayered with different types of resins.   The packaging material for an electrochemical cell according to any one of claims 1 to 3, wherein the base material layer and the adhesive layer are laminated on the barrier layer by a thermal laminating method.   The packaging material for an electrochemical cell according to any one of claims 1 to 3, wherein the base material layer and the adhesive layer are laminated on the barrier layer by a sand lamination method.   The electrochemical cell packaging material according to any one of claims 1 to 5, wherein the barrier layer is subjected to chemical conversion treatment on at least one surface of the metal foil.

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