JP5962346B2 - Battery packaging materials - Google Patents

Description

  The present invention relates to a battery packaging material that is lightweight, has good durability against an electrolyte, water vapor barrier properties, and insulating properties, and has biodegradability.

  Conventionally, various types of batteries have been developed. In any battery, a packaging material is an indispensable member for sealing battery elements such as electrodes and electrolytes. Conventionally, metal packaging materials have been frequently used as battery packaging.

  On the other hand, in recent years, with the improvement in performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, etc., batteries are required to have various shapes, and are also required to be thinner and lighter. However, metal battery packaging materials that have been widely used in the past have the disadvantages that it is difficult to follow the diversification of shapes and that there is a limit to weight reduction.

  Thus, in recent years, as a battery packaging material that can be easily processed into various shapes and can be made thinner and lighter, for example, as shown in Patent Document 1, a base material layer / barrier layer / sealant layer A film-like laminate in which are sequentially laminated has been proposed. Such a film-like laminate is utilized as a packaging material for a battery by thermally welding sealant layers positioned at the periphery of the battery element to seal the battery element and sealing the battery element. In film-like laminates used as conventional battery packaging materials, resins such as nylon and polyethylene terephthalate are used as the base layer, metal foils such as aluminum foil are used as the barrier layer, and resins such as polypropylene and polyethylene are used as the sealant layer. ing.

  However, in battery packaging materials made of conventional film-like laminates, metal foil is used as a barrier layer, so that polyethylene or polypropylene in the sealant layer is excessively crushed during heat sealing when sealing battery elements. Thus, there is a drawback that the battery electrode and the metal foil of the battery packaging material easily cause a short circuit.

  In addition, in battery packaging materials made of conventional film-like laminates, (1) cracks are likely to occur in the stretching process of the molding process, and (2) in the heat treatment in the battery packaging material or battery manufacturing process, the sealant layer May be heated above the melting point of polyethylene or polypropylene, and the crystallinity cannot be managed in the subsequent cooling process, so cracks are likely to occur. (3) Cooling after sealing the battery element (after heat sealing) Since it is not possible to manage the crystallinity at the stage, cracks are likely to occur particularly in the folding process of the seal part. (4) When foreign substances are mixed in the sealant layer, cracks are likely to occur along the crystal parts starting from the foreign substances. For these reasons, there is also a drawback that cracks are likely to occur in the sealant layer during manufacturing or processing. If cracks occur in the sealant layer, the electrolytic solution may penetrate into the barrier layer to form metal deposits, which may result in a short circuit.

  Thus, in the battery packaging material using metal foil, the problem of a short circuit is inevitably accompanied.

  Although weight reduction is desired for battery packaging materials, when using metal foil as a barrier layer, the metal foil occupies most of the total weight of the battery packaging material, so there is a limit to weight reduction. is there.

  Furthermore, in recent years, there has been a social demand for reducing environmental impact, but battery packaging materials made of conventional film-like laminates have been designed with an emphasis on being able to withstand long-term use and are disposed of. It is not satisfactory in terms of reducing the environmental impact of time.

  Therefore, in battery packaging materials composed of a film-like laminate, if an alternative material other than metal foil can be used as the barrier layer, it can lead to overcoming the above-mentioned drawbacks and problems, but the barrier layer has a water vapor barrier property, Since it is necessary to have a function such as heat resistance, a practical packaging material that employs an alternative material other than metal foil as a barrier layer has not yet been developed.

JP 2008-288117 A

  The present invention has been made in view of the above problems, and provides a battery packaging material that is lightweight, has good durability against an electrolytic solution, water vapor barrier properties, and insulating properties, and has biodegradability. With the goal.

  The present inventor has intensively studied to solve the above problems. As a result, in the battery packaging material comprising a laminate in which a base material layer, a barrier layer, and a sealant layer are sequentially laminated, a metal foil is used as the barrier layer. It has been found that the use of a resin layer containing a polyglycolic acid resin without using a resin makes it lightweight and has good durability against an electrolytic solution, water vapor barrier properties, and insulating properties. Furthermore, it has also been found that the battery packaging material has biodegradability, and can reduce the environmental load during disposal. The present invention has been completed by further studies based on such knowledge.

That is, this invention provides the battery packaging material and battery of the aspect hung up below.
Item 1. It consists of a laminate in which at least a base material layer, a barrier layer, and a sealant layer are sequentially laminated,
The barrier layer is formed of a resin layer containing a polyglycolic acid resin.
A battery packaging material characterized by the above.
Item 2. Item 2. The battery packaging material according to Item 1, wherein an adhesive layer is formed between the base material layer and the barrier layer and / or between the barrier layer and the sealant layer.
Item 3. Item 3. The battery packaging material according to Item 1 or 2, wherein a polyglycolic acid resin is contained in at least one of the base material layer and the sealant layer.
Item 4. Item 4. The battery packaging material according to any one of Items 1 to 3, which is a packaging material for a secondary battery.
Item 5. Item 5. A battery in which a battery element including at least a positive electrode, a negative electrode, and an electrolyte is accommodated in the battery packaging material according to any one of Items 1 to 4.

  The battery packaging material of the present invention uses a resin layer containing a polyglycolic acid resin as a barrier layer, and has the advantage of being lighter than conventional battery packaging materials using metal foil. Furthermore, it also has biodegradability, and can reduce the environmental load at the time of disposal. The “biodegradability” with respect to the battery packaging material of the present invention means that at least the barrier layer portion exhibits biodegradability, and that all constituent materials other than the barrier layer necessarily exhibit biodegradability. It doesn't mean.

  In addition, the battery packaging material of the present invention is excellent in durability against an electrolytic solution and has a good water vapor barrier property and insulation property even though no metal foil is used as a barrier layer. It has sufficient functionality required for packaging materials.

It is a figure which shows an example of the cross-section of the packaging material for batteries of this invention.

  The battery packaging material of the present invention comprises a laminate in which at least a base material layer, a barrier layer, and a sealant layer are sequentially laminated, and the barrier layer is formed of a resin layer containing a polyglycolic acid resin. It is characterized by. Hereinafter, the battery packaging material of the present invention will be described in detail.

1. Laminated structure of battery packaging material The battery packaging material comprises a laminate in which at least a base material layer 1, a barrier layer 3, and a sealant layer 5 are sequentially laminated. In the battery packaging material of the present invention, the base material layer 1 is the outermost layer, and the sealant layer 5 is the innermost layer. That is, when the battery is assembled, the sealant layers 5 positioned at the periphery of the battery element are thermally welded to seal the battery element, thereby sealing the battery element.

  Moreover, in the battery packaging material of the present invention, an adhesive layer 2 may be provided between the base material layer 1 and the barrier layer 3 as necessary for the purpose of enhancing these adhesive properties. Further, in the battery packaging material of the present invention, an adhesive layer 4 may be provided between the barrier layer 3 and the sealant layer 5 as necessary for the purpose of enhancing the adhesion.

  FIG. 1 is a cross-sectional view of a laminate having a layer structure in which a base material layer 1, an adhesive layer 2, a barrier layer 3, an adhesive layer 4, and a sealant layer 5 are sequentially laminated as an example of the battery packaging material of the present invention. Show.

2. Layer composition and manufacturing method of battery packaging material [base material layer 1]
In the battery packaging material of the present invention, the base material layer 1 is a layer forming the outermost layer. The material for forming the base material layer 1 is not particularly limited as long as it has insulating properties. Examples of the material for forming the base material layer 1 include polyester resin, polyamide resin, polyglycolic acid resin, epoxy resin, acrylic resin, fluorine resin, polyurethane resin, silicon resin, phenol resin, polyetherimide resin, and polyether monkey. Phon resin, polyphenyl sulfone resin, polyphenyl sulfide resin, polyether ether ketone resin, and mixtures and copolymers thereof.

  Examples of the polyester resin used as the base material layer 1 include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, and a copolymer polyester mainly composed of ethylene terephthalate, Examples thereof include copolymer polyesters mainly composed of butylene terephthalate as a repeating unit. The copolymer polyester mainly composed of ethylene terephthalate as a repeating unit is specifically a copolymer polyester (hereinafter referred to as polyethylene (terephthalate / isophthalate) which is polymerized with ethylene isophthalate mainly composed of ethylene terephthalate as a repeating unit. Abbreviated to phthalate), polyethylene (terephthalate / isophthalate), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxy) Rate) and polyethylene (terephthalate / decane dicarboxylate). The copolymer polyester mainly composed of butylene terephthalate as a repeating unit is specifically a copolymer polyester (hereinafter referred to as polybutylene (terephthalate / isophthalate), which is polymerized with butylene isophthalate mainly having butylene terephthalate as a repeating unit. Abbreviated to phthalate), polybutylene (terephthalate / adipate), polybutylene (terephthalate / sebacate), polybutylene (terephthalate / decanedicarboxylate), and polybutylene naphthalate. Moreover, you may use the blend resin which mixed the bisphenol A polycarbonate with the said polyester as a polyester resin. Among these polyester resins, 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. As these polyester resins, one kind of polyester resin may be used alone, or a blend resin obtained by mixing two or more kinds of polyester resins may be used. The polyester resin is excellent in electrolytic solution resistance and has characteristics that whitening or the like hardly occurs with respect to adhesion of the electrolytic solution, and is suitably used as the base material layer 1.

Examples of the polyamide resin used as the base material layer 1 include polyamide and copolymer polyamide. Specific examples of polyamide include nylon 6, nylon 66, nylon 12, and the like. Specific examples of the copolyamide include [NH (CH ₂ ) ₅ CO], [NH (CH ₂ ) ₆ NHCO (CH ₂ ) ₄ CO], [NH (CH ₂ ) ₆ NHCO ( Examples thereof include crystalline and amorphous copolyamides having at least two kinds selected from CH ₂ ) ₈ CO], [NH (CH ₂ ) ₁₀ CO], and [NH (CH ₂ ) ₁₁ CO] as structural units. It is done. Further, as the polyamide resin, more specifically, an aliphatic polyamide such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46; nylon 6I containing a structural unit derived from terephthalic acid and / or isophthalic acid, Nylon 6T, nylon 6IT, nylon 6I6T (I represents isophthalic acid, T represents terephthalic acid) and other hexamethylenediamine-isophthalic acid-terephthalic acid copolymerized polyamides; aromatics such as polymetaxylylene adipamide (MXD6) Polyamide containing poly; alicyclic polyamide such as polyaminomethylcyclohexyl adipamide (PACM6); polyamide copolymerized with lactam component and isocyanate component such as 4,4′-diphenylmethane-diisocyanate; copolyamide and polyester In polymer Specific polyester amide copolymer; polyether ester amide copolymer which is a copolymer of copolyamide and polyalkylene ether glycol. As these polyamide resins, one kind of polyamide resin may be used alone, or a blend resin obtained by mixing two or more kinds of polyamide resins may be used.

  The polyglycolic acid resin used as the base material layer 1 is the same as that used in the barrier layer 3.

  Among these, preferably polyamide resin, polyester resin, polyglycolic acid resin, more preferably stretched polyamide, stretched polyester, stretched polyglycolic acid, more preferably biaxially stretched nylon, biaxially stretched polyester, biaxially stretched polyglycolic acid Is mentioned. The stretched polyamide is excellent in stretchability and can prevent whitening due to resin cracking of the base material layer during molding. Further, the stretched polyester is excellent in electrolytic solution resistance, hardly corroded with respect to the electrolyte solution that has penetrated to the base material layer 1, and the occurrence of whitening due to the corrosion of the base material layer 1 is more effectively prevented. . In addition, when stretched polyglycolic acid is used as the base material layer 1, the battery packaging material of the present invention can be provided with more excellent biodegradability. Moreover, the nylon, polyester, and polyglycolic acid produced by the biaxial stretching treatment have the resin film oriented and crystallized, so that the heat resistance of the base material layer 1 can be improved.

  The base material layer 1 may be formed of one resin layer, but may be formed of two or more resin layers in order to improve pinhole resistance and insulation. When the base material layer 1 is formed of two or more resin layers, as a specific example of the base material layer 1, a multilayer structure in which a resin layer made of polyester and a resin layer made of nylon are laminated, preferably biaxial stretching The multilayer structure which laminated | stacked the resin layer which consists of polyester, and the resin layer which consists of biaxially-stretched nylon is mentioned. When making the base material layer 1 into a multilayer structure, you may adhere | attach via an adhesive agent and may laminate | stack directly without using an adhesive agent. In the case of bonding without using an adhesive, bonding in a hot melt state such as a co-extrusion method, a sand lamination method, or a thermal laminating method is preferable. In the case of bonding via an adhesive, this adhesive may be a two-component curable adhesive or a one-component curable adhesive. Further, the bonding mechanism of the adhesive is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a heat melting type, a hot pressure type, an electron beam curing type such as UV and EB, and the like. The adhesive component to be bonded is not particularly limited, but polyester resin, polyurethane resin, epoxy resin, phenol resin resin, polyamide resin, polyolefin resin, polyvinyl acetate resin, cellulose resin, ( Examples include (meth) acrylic resins, polyimide resins, amino resins, rubbers, silicon resins, and the like. These adhesive components may be used alone or in combination of two or more.

  The base material layer 1 may be subjected to a low friction treatment on at least one surface, preferably the surface opposite to the barrier layer 3 side. Thus, the moldability can be improved by reducing the friction of at least one surface of the base material layer 1. As the low friction treatment, for example, any treatment may be used as long as the friction coefficient of the outermost surface of the base material layer 1 is 1.0 or less. Specifically, a mat treatment method, a slip agent thin film, Examples thereof include a method of forming a layer, a method of combining these, and the like.

  The matting treatment of the base material layer 1 is carried out by adding a matting agent to the base material layer 1 in advance to form irregularities on the surface, transferring the surface by heating or pressurizing with an embossing roll, or subjecting the surface to a dry or wet blasting method or a file. The method of mechanically ruining is mentioned. In addition, as the matting treatment of the base material layer 1, an appropriately selected resin and a matting agent are mixed, coated on the surface of the base material layer 1, heat drying, heat aging, high temperature baking, electron beam irradiation, ultraviolet ray irradiation, etc. And a method of forming a strong resin layer on the surface of the base material layer 1. Examples of the matting agent include fine particles having a particle size of about 0.5 nm to 5 μm, and examples of the constituent material include metals, metal oxides, inorganic substances, and organic substances. Specific examples of the shape of the matting agent include a spherical shape, a fiber shape, a plate shape, an indeterminate shape, and a balloon shape. Specific constituent materials for the matting agent include talc, silica, graphite, kaolin, montmorilloid, montmorillonite, synthetic mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide. , Aluminum oxide, neodymium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, alumina, carbon black, carbon Nanotubes, high melting point nylon, cross-linked acrylic, cross-linked styrene, cross-linked polyethylene, benzoguanamine, gold, aluminum, copper, nickel, diamond, fluororesin (eg polytetrafluoride Tylene (PTFE), Polytrifluoroethylene (PCTFE), Polyvinylidene Fluoride (PVDF), Polyvinyl Fluoride (PVF), Polyethylene Tetrafluoroethylene Copolymer (FTFE), Polytetrafluoroethylene / Hexafluoropropylene Copolymer (FEP) and the like. Among these matting agents, silica, barium sulfate, and titanium oxide are publicly used because they have good dispersibility and can be matted with a small amount. These matting agents may be used individually by 1 type, and may be used in combination of 2 or more type.

  As a method of forming a thin film layer of a slip agent on the base material layer 1, a method of adding a slip agent to the base material layer 1 and depositing it on the surface by bleed-out, a layer containing the slip agent in the base material layer 1 The method of laminating | stacking is mentioned. When laminating a layer containing a slip agent, the slip agent may be laminated alone, or after mixing the slip agent with an appropriately selected resin and coating the surface of the base material layer 1, heat drying, heat aging Further, curing treatment such as high-temperature baking, electron beam irradiation, and ultraviolet irradiation may be performed and laminated on the surface of the base material layer 1 as a strong resin layer. The slip agent may be any component that can exhibit slip properties. Specifically, fatty acid amide, metal soap, hydrophilic silicone, silicone grafted acrylic, silicone grafted epoxy, silicone grafted polyether, Silicone grafted polyester, block silicone acrylic copolymer, polyglycerol-modified silicone, paraffin, fluororesin (eg, polytetrafluoroethylene (PTFE), polytrifluoride ethylene (PCTFE), polyvinylidene fluoride (PVDF) , Polyvinyl fluoride (PVF), polyethylene tetrafluoride ethylene copolymer (FTFE), polytetrafluoroethylene / hexafluoropropylene copolymer (FEP), etc.). These slip agents may be used individually by 1 type, and may be used in combination of 2 or more type. Moreover, you may perform formation of the thin film layer by a slip agent in combination with a low friction process.

  In addition, an anti-electrolytic solution for preventing discoloration or dissolution of the base material layer 1 even when an insulating treatment or an electrolytic solution adheres to the surface of the base material layer 1 subjected to the friction reduction treatment, if necessary. Various surface treatments such as treatment may be performed.

  These surface treatments may be performed singly or in combination of two or more. Moreover, when surface-treating to the surface of the base material layer 1, about the thickness of a surface treatment part, although it does not restrict | limit in particular, 0.1 nm-15 micrometers are mentioned, for example.

  Moreover, in order to improve adhesiveness with the barrier layer 3, the easily bonding layer may be formed in the side facing the barrier layer 3 of the base material layer 1 as needed. The easy adhesion layer can be formed by, for example, a crosslinked resin layer obtained by crosslinking a resin such as polyurethane resin, acrylic resin, epoxy resin, phenol resin, isocyanate resin, benzoguanamine resin, melamine resin. The easy-adhesion layer is formed by applying the curing agent used for the fat and its crosslinking reaction onto the base layer 1 by an application method such as an extrusion method, a gravure coating method, a roll coating method, a die coating method, or a dipping method. It is formed by curing.

  In addition, a thin film of metal, metal oxide, metal nitride, metal carbide or the like is formed on at least one surface of the base material layer 1 by vapor deposition or sputtering, as necessary, in order to improve the water vapor barrier property. May be. As a material for forming such a thin film, aluminum, aluminum oxide, and silicon oxide are preferably used from the viewpoint of ease of processing and reduction of processing cost. Moreover, the base material layer 1 may be subjected to corona treatment, blast treatment, or the like in order to improve or stabilize film forming property, lamination processing, suitability for final product secondary processing (pouching, embossing), and the like. Surface activation treatment such as oxidation treatment or ozone treatment may be performed.

  About the thickness of the base material layer 1, 10-50 micrometers is mentioned, for example, Preferably 15-30 micrometers is mentioned.

[Adhesive layer 2]
In the battery packaging material of the present invention, the adhesive layer 2 is a layer provided between the base material layer 1 and the barrier layer 3 as necessary in order to firmly bond the base material layer 1 and the barrier layer 3.

  The adhesive layer 2 is formed of an adhesive that can bond the base material layer 1 and the barrier layer 3 together. The adhesive used for forming the adhesive layer 2 may be a two-component curable adhesive or a one-component curable adhesive. Furthermore, a solvent-soluble type, a solvent-dispersed type, and a solventless type may be used. The bonding mechanism of the adhesive used for forming the adhesive layer 2 is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a heat melting type, a thermocompression bonding type, a radiation curable type such as an electron beam or ultraviolet ray, and the like. It may be.

  Specific examples of the adhesive component that can be used to form the adhesive layer 2 include polyester resins, polyether resins, polyurethane resins, epoxy resins, phenolic resins, polyamide resins, polyolefin resins, and cyclic polyolefins. Resin; Carboxylic acid modified polyolefin resin; Carboxylic acid modified cyclic polyolefin resin; Polyvinyl acetate resin; Cellulose adhesive; (Meth) acrylic resin; Polyimide resin; Urea resin, amino resin; Rubber; Examples thereof include resins.

  Specific examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, and copolyester.

  Specific examples of the polyamide-based resin include nylon 6, nylon 66, nylon 12, and copolymerized polyamide.

Specific examples of the polyolefin resin include low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, polyethylene block copolymer (for example, block copolymer of ethylene and butene, block of ethylene and acrylic acid). Polyethylene, such as copolymers, block copolymers of ethylene and methacrylic acid), random copolymers of polyethylene (eg, random copolymers of ethylene and butene, random copolymers of ethylene and acrylic acid, random copolymers of ethylene and methacrylic acid, etc.);
Homopolypropylene, polypropylene block copolymers (eg, propylene and ethylene block copolymers, propylene and butene block copolymers, propylene and acrylic acid block copolymers, ethylene and methacrylic acid block copolymers, etc.), polypropylene random copolymers (eg, propylene Crystalline or amorphous polypropylene such as a random copolymer of ethylene and ethylene, a random copolymer of propylene and butene, a random copolymer of propylene and acrylic acid, a random copolymer of propylene and methacrylic acid, etc .; a terpolymer of ethylene-butene-propylene; These metal cross-linked products are exemplified.

  The cyclic polyolefin resin is a copolymer of an olefin and a cyclic monomer. Examples of the olefin that is a constituent monomer of the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, and isoprene. Examples of the cyclic monomer that is a constituent monomer of the cyclic polyolefin include cyclic alkenes such as norbornene; specifically, cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene.

  The carboxylic acid-modified polyolefin resin is obtained by copolymerizing a part of the monomer constituting the polyolefin resin instead of the α, β-unsaturated carboxylic acid or its anhydride, or for the polyolefin resin. It is a polymer obtained by block polymerization or graft polymerization of α, β-unsaturated carboxylic acid or its anhydride. The polyolefin resin to be modified with carboxylic acid is the same as described above. Examples of the carboxylic acid used for modification include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, itaconic anhydride and the like.

  The carboxylic acid-modified cyclic polyolefin and the resin are obtained by copolymerizing a part of the monomer constituting the cyclic polyolefin in place of the α, β-unsaturated carboxylic acid or its anhydride, or α , Β-unsaturated carboxylic acid or its anhydride is a polymer obtained by block polymerization or graft polymerization. The cyclic polyolefin resin to be modified with carboxylic acid is the same as described above. The carboxylic acid used for modification is the same as that used for modification of the carboxylic acid-modified polyolefin resin.

  Specific examples of the rubber include chloroprene rubber, nitrile rubber, and styrene-butadiene rubber.

  These adhesive components may be used individually by 1 type, and may be used in combination of 2 or more type.

  Among the adhesive components, preferably, a polyurethane two-component curable adhesive, a carboxylic acid-modified polyolefin resin, and a carboxylic acid-modified cyclic polyolefin resin are used.

  In addition to these adhesive components, the adhesive layer 2 may contain a polyglycolic acid resin as necessary. By containing the polyglycolic acid resin in the adhesive layer 2, the adhesion between the base material layer 1 and the barrier layer 3 becomes better, and further the biodegradability of the battery packaging material of the present invention can be further improved. It becomes possible. The type of polyglycolic acid resin added to the adhesive layer 2 is the same as that used for the barrier layer 3. When the polyglycolic acid resin is contained in the adhesive layer 2, the content thereof is not particularly limited. For example, the polyglycolic acid resin is 5 to 80 parts by weight per 100 parts by weight of the adhesive layer 2, and preferably 30-70 weight part is mentioned.

  About the thickness of the contact bonding layer 2, 2-50 micrometers, for example, Preferably 3-25 micrometers is mentioned.

  The adhesive layer 2 is formed on the base material layer 1 or the barrier layer 3 by gravure coating, roll coating, melt extrusion, or the like. Lamination of the base material layer 1 and the barrier layer 3 through the adhesive layer 2 can be performed by a dry lamination method, a thermal lamination method, a coextrusion lamination method, a sand lamination method, a combination thereof, or the like. Further, after laminating the base material layer 1 and the barrier layer 3 through the adhesive layer 2, in order to strengthen the adhesiveness of the adhesive layer 2, as necessary, a hot roll contact type, a hot air type, a near or You may use for heat processing, such as a far-infrared type. Examples of such heating conditions include 150 to 210 ° C. and 1 to 10 seconds.

[Barrier layer 3]
In the battery packaging material of the present invention, the barrier layer 3 is a layer that functions as a barrier layer for preventing water vapor, oxygen, light, and the like from entering the battery, in addition to improving the strength of the packaging material. In the present invention, the barrier layer 3 is formed of a resin layer containing a polyglycolic acid resin. Thus, by using a polyglycolic acid resin as the barrier layer 3, the battery packaging material of the present invention is lightweight and biodegradable while improving the durability against the electrolytic solution, the water vapor barrier property, and the insulating property. Can be provided with sex.

  The polyglycolic acid resin used in the present invention is a glycolic acid homopolymer consisting only of a repeating unit of glycolic acid represented by the following general formula (1) (ring-opening polymerization of glycolide which is a bimolecular cyclic ester of glycolic acid) And a copolymer of glycolic acid containing repeating units of glycolic acid represented by the following general formula (1).

  In the glycolic acid copolymer, examples of the comonomer copolymerized with the glycolic acid monomer include, for example, ethylene oxalate (that is, 1,4-dioxane-2,3-dione), lactides, and lactones (for example, β-pro Piolactone, β-butyrolactone, β-pivalolactone, γ-butyrolactone, δ-valerolactone, β-methyl-δ-valerolactone, ε-caprolactone, etc.), carbonates (eg, trimethyline carbonate, etc.), ethers (eg, Cyclic monomers such as 1,3-dioxane, ether esters (eg, dioxanone), amides (eg, caprolactam); lactic acid, 3-hydroxypropanoic acid, 3-hydroxybutanoic acid, 4-hydroxybutanoic acid, 6 -Hydroxycarboxylic acids such as hydroxycaproic acid Or an alkyl ester thereof; a substantially equimolar mixture of an aliphatic diol such as ethylene glycol or 1,4-butanediol and an aliphatic dicarboxylic acid such as succinic acid or adipic acid or an alkyl ester thereof. Can be mentioned. These comonomers may be used individually by 1 type, and may be used in combination of 2 or more type.

  In the glycolic acid copolymer, the proportion of glycolic acid monomer is usually 70% by weight or more, preferably 90 to 99% by weight. If the glycolic acid monomer is contained at such a ratio, it is possible to more effectively provide durability against the electrolytic solution required for the barrier layer and water vapor barrier properties.

  Examples of the molecular weight of the polyglycolic acid resin used for the barrier layer 3 include 30,000 to 600,000 in terms of weight average molecular weight (in terms of polymethyl methacrylate) in GPC measurement using a hexafluoroisopropanol solvent. By satisfying such a molecular weight, breakage during molding, resin coloring, generation of decomposition products, and the like can be suppressed, and the barrier layer 3 can be stably formed.

  In the barrier layer 3, the polyglycolic acid resin may be used singly or in combination of two or more of homopolymers of polyglycolic acid and copolymers of polyglycolic acid.

  The barrier layer 3 is preferably formed of a resin composed of the polyglycolic acid resin alone, but includes resins other than the polyglycolic acid resin as long as the effects of the present invention are not hindered. It may be. Examples of resins other than the polyglycolic acid resin used for the barrier layer 3 include polyolefin resins, ethylene vinyl alcohol copolymers, and fluorine resins. Specific examples of the polyolefin resin used for the barrier layer 3 are the same as those of the polyolefin resin used as an adhesive component in the adhesive layer 2. When the barrier layer 3 contains a resin other than the polyglycolic acid resin, the content of the polyglycolic acid resin in the resin constituting the barrier layer 3 is, for example, 70% by weight or more, preferably 90 to 99% by weight. Is mentioned.

  In addition, a thin film of metal, metal oxide, metal nitride, metal carbide or the like is formed on at least one surface of the barrier layer 3 by vapor deposition or sputtering as necessary in order to improve the water vapor barrier property. Also good. As a material for forming such a thin film, aluminum, aluminum oxide, and silicon oxide are preferably used from the viewpoint of ease of processing and reduction of processing cost.

  Furthermore, the barrier layer 3 may contain additives such as a heat stabilizer, a plasticizer, and a lubricant, as necessary, within a range not impeding the effects of the present invention.

  The barrier layer 3 may be subjected to corona treatment, blast treatment, oxidation treatment, in order to improve or stabilize film forming property, lamination processing, suitability for final product secondary processing (pouching, embossing), etc. Surface activation treatment such as ozone treatment may be performed.

  About the thickness of the barrier layer 3, 10-2000 micrometers is preferable, for example, Preferably it is 30-500 micrometers.

  The barrier layer 3 may be formed using a film made of a resin containing a polyolefin resin, or may be formed by melt extrusion of a resin containing a polyolefin resin. When using a film made of a resin containing a polyolefin-based resin, the film may be unstretched, uniaxially stretched, or biaxially stretched. When a film made of a resin containing a polyolefin resin is used, the barrier layer 3 can be laminated by a dry lamination method, a thermal lamination method, a sand lamination method, or the like. When a resin containing a polyolefin resin is formed by melt extrusion, the barrier layer 3 is laminated by a method of co-extrusion with the base material layer 1 and / or the sealant layer 5, a thermal lamination method, a sand lamination method, or the like. Can do.

[Adhesive layer 4]
In the battery packaging material of the present invention, the adhesive layer 4 is a layer provided between the barrier layer 3 and the sealant layer 5 as necessary in order to firmly bond them.

  The adhesive layer 4 is formed of an adhesive that can adhere the barrier layer 3 and the sealant layer 5. The adhesive used for forming the adhesive layer 4 may be a two-component curable adhesive or a one-component curable adhesive. Furthermore, a solvent-soluble type, a solvent-dispersed type, and a solventless type may be used. The bonding mechanism of the adhesive used for forming the adhesive layer 4 is not particularly limited, and any of a chemical reaction type, a solvent volatilization type, a heat melting type, a thermocompression bonding type, a radiation curable type such as an electron beam and an ultraviolet ray, etc. It may be.

  Specific examples of the adhesive component used to form the adhesive layer 4 are the same as the adhesive component used in the adhesive layer 2.

  The adhesive component used for forming the adhesive layer 4 is appropriately set according to the composition of the sealant layer 5 and the like. Among the adhesive components described above, the barrier layer 3 and the sealant layer 5 are more stable. From the viewpoint of bonding, a carboxylic acid-modified polyolefin resin, a carboxylic acid-modified cyclic polyolefin resin, a two-component curable urethane adhesive, and a carboxylic acid-modified polyolefin resin are more preferable.

  Among the carboxylic acid-modified polyolefin resins used for forming the adhesive layer 4, as a particularly preferred example, a carboxylic acid-modified homopolypropylene having a bigat softening point of 115 ° C. or higher and a melting point of 150 ° C. or higher; a bigat softening point of 105 ° C. Examples thereof include a carboxylic acid-modified ethylene-propylene copolymer having a melting point of 130 ° C. or higher; a polypropylene or a propylene copolymer modified with an unsaturated carboxylic acid having a melting point of 110 ° C. or higher.

  These adhesive components may be used individually by 1 type, and may be used in combination of 2 or more type.

  In addition to these adhesive components, the adhesive layer 4 may contain a polyglycolic acid resin as necessary. By including a polyglycolic acid resin in the adhesive layer 4, the adhesion between the barrier layer 3 and the sealant layer 5 becomes better, and the biodegradability of the battery packaging material of the present invention can be further improved. become. The type of polyglycolic acid resin added to the adhesive layer 4 is the same as that used in the barrier layer 3. When the polyglycolic acid resin is contained in the adhesive layer 4, the content thereof is not particularly limited. For example, the polyglycolic acid resin is 5 to 80 parts by weight per 100 parts by weight of the adhesive component contained in the adhesive layer 4. , Preferably 30-70 weight part is mentioned.

  About the thickness of the contact bonding layer 4, 2-50 micrometers, for example, Preferably 3-25 micrometers is mentioned.

  The adhesive layer 4 is formed on the base material layer 1 or the barrier layer 3 by gravure coating, roll coating, melt extrusion, or the like. Lamination of the barrier layer 3 and the sealant layer 5 via the adhesive layer 4 can be performed by a dry lamination method, a thermal lamination method, a coextrusion lamination method, a sand lamination method, a combination thereof, or the like. Further, after laminating the barrier layer 3 and the sealant layer 5 via the adhesive layer 4, in order to strengthen the adhesiveness of the adhesive layer 4, a hot roll contact type, a hot air type, a near or far distance is used as necessary. You may use for heat processings, such as an infrared type. Examples of such heating conditions include 150 to 210 ° C. and 1 to 10 seconds.

[Sealant layer 5]
In the battery packaging material of the present invention, the sealant layer 5 corresponds to the innermost layer and is a layer that seals the battery element by heat-sealing the sealant layers when the battery is assembled.

  The resin component used in the sealant layer 5 is not particularly limited as long as it can be thermally welded. For example, polyolefin resin, cyclic polyolefin resin, carboxylic acid modified polyolefin resin, carboxylic acid modified cyclic polyolefin Examples thereof include resins.

  Specific examples of the polyolefin resin, the cyclic polyolefin resin, the carboxylic acid-modified polyolefin resin, and the carboxylic acid-modified cyclic polyolefin resin used for the sealant layer 5 are the same as those exemplified in the adhesive layer 2.

  About the resin component used for the sealant layer 5, it is preferable to use properly according to the type of the battery element to accommodate. For example, when sealing a battery element in the battery packaging material of the present invention, when a tab film is interposed between the thermal adhesive layer, the positive electrode tab, and the negative electrode tab, as a resin component used for the sealant layer 5 Polyolefin resins and cyclic polyolefin resins are preferably used. When the tab film is not interposed, a carboxylic acid-modified polyolefin resin or a carboxylic acid-modified cyclic polyolefin resin is preferably used as the resin component used for the sealant layer 5.

  The sealant layer 5 may be formed of one kind of resin component alone, or may be formed of a blend polymer in which two or more kinds of resin components are combined.

  In addition to the resin component, the sealant layer 5 may contain a polyglycolic acid resin as necessary. By containing the polyglycolic acid resin in the sealant layer 5, the biodegradability of the battery packaging material of the present invention can be further improved. The type of polyglycolic acid resin used for the sealant layer 5 is the same as that used for the barrier layer 3. When the polyglycolic acid resin is contained in the sealant layer 5, the content thereof is not particularly limited. For example, the polyglycolic acid resin is 5 to 80 parts by weight, preferably 30 parts per 100 parts by weight of the total amount of the sealant layer 5. -70 weight part is mentioned.

  The sealant layer 5 may be formed of only one layer, but may be formed of two or more layers using the same or different resin components.

  In order to improve or stabilize the film forming property, laminating processing, suitability of the final product secondary processing (pouching, embossing), etc., the sealant layer 5 may be subjected to corona treatment, blast treatment, oxidation treatment, Surface activation treatment such as ozone treatment may be performed.

  In addition, the thickness of the sealant layer 5 can be selected as appropriate, and may be 2 to 2000 μm, preferably 5 to 1000 μm, and more preferably 10 to 500 μm.

  The sealant layer 5 may be formed using a film containing the resin component, or the resin component may be formed by melt extrusion. When a film containing the resin component is used, the film may be unstretched, uniaxially stretched, or biaxially stretched. When the film containing the resin component is used, the sealant layer 5 can be laminated by a dry lamination method, a thermal lamination method, a sand lamination method, or the like. When the resin component is formed by melt extrusion, the sealant layer 5 can be laminated by a method of co-extrusion with the barrier layer 3, a thermal lamination method, a sand lamination method, or the like.

3. Application of Battery Packaging Material The battery packaging material of the present invention is used as a packaging material for sealing and housing battery elements such as a positive electrode, a negative electrode, and an electrolyte.

  Specifically, a battery element including at least a positive electrode, a negative electrode, and an electrolyte is formed using the battery packaging material of the present invention, with the metal terminals connected to each of the positive electrode and the negative electrode protruding outward. A battery using a battery packaging material is formed by covering the periphery of the element so that a flange portion (a region where the sealant layers are in contact with each other) can be formed, and heat-sealing and sealing the sealant layers of the flange portion. Provided. In addition, when accommodating a battery element using the battery packaging material of the present invention, the battery packaging material of the present invention is used such that the sealant portion is on the inner side (surface in contact with the battery element).

  The battery packaging material of the present invention may be used for either a primary battery or a secondary battery, but is preferably a secondary battery. The type of secondary battery to which the battery packaging material of the present invention is applied is not particularly limited. For example, a lithium ion battery, a lithium ion polymer battery, a lead battery, a nickel / hydrogen battery, a nickel / cadmium battery , Nickel / iron livestock batteries, nickel / zinc livestock batteries, silver oxide / zinc livestock batteries, metal-air batteries, polyvalent cation batteries, capacitors, capacitors and the like. Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries are suitable applications for the battery packaging material of the present invention.

  Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples. The polyglycolic acid used in the following examples and comparative examples is trade name “KUREDUX” (Kureha Co., Ltd.).

Example 1
A battery packaging material comprising a laminate having a layer structure having the following composition was produced.
Base material layer 1 : Biaxially stretched polyamide (nylon 6, thickness 25 μm) with silicon oxide deposited on one side
Adhesive layer 2 : Two-component urethane adhesive (thickness 4 μm) of polyester polyol (main agent) and toluene diisocyanate (curing agent)
Barrier layer 3 : film formed using polyglycolic acid (thickness 50 μm)
Adhesive layer 4 : Two-component urethane adhesive (thickness 4 μm) of polyester polyol (main agent) and toluene diisocyanate (curing agent)
Sealant layer 5 : film formed using random polypropylene (thickness: 35 μm)

  After laminating the adhesive layer 2 and the barrier layer 3 on the base material layer 1 by the dry lamination method, the adhesive layer 4 and the sealant layer 5 were laminated on the barrier layer 3 by the dry lamination method. Specifically, the adhesive layer 2 is applied to the side on which the silicon oxide is deposited on the base material layer 1 and bonded to the barrier layer 3 under pressure and heat, and then an aging treatment is performed at 60 ° C. for 24 hours. Thereby, the laminated body of base material layer 1 / adhesion layer 2 / barrier layer 3 was prepared. Next, after applying the adhesive layer 4 to the barrier layer 3 side of the laminate and pasting with the sealant layer 5 under pressure and heating, an aging treatment is performed at 60 ° C. for 24 hours, whereby the base material layer 1 / adhesion A battery packaging material comprising a laminate in which layer 2 / barrier layer 3 / adhesive layer 4 / sealant layer 5 were laminated in order was obtained.

Example 2
A battery packaging material comprising a laminate having a layer structure having the following composition was produced.
Base material layer 1 : Biaxially stretched polyethylene terephthalate (thickness 25 μm) having an easy-adhesion layer formed on one surface
Adhesive layer 2 : maleic acid-modified polypropylene (thickness 5 μm)
Barrier layer 3 : film formed using polyglycolic acid (thickness 50 μm)
Adhesive layer 4 : maleic acid-modified polypropylene (thickness: 15 μm)
Sealant layer 5 : Mixed resin (thickness 35 μm) of 70 parts by weight of polyglycolic acid and 30 parts by weight of random polypropylene

  The base material layer 1 is composed of 100 parts by weight of a polyurethane resin obtained by reacting a prepolymer made of polyether polyol with an aliphatic polyisocyanate on one surface of biaxially stretched polyethylene terephthalate, and a triad as a curing agent. A resin composition mixed with 5 parts by weight of a methylol melamine resin was applied by a gravure coating method and prepared by aging treatment at 40 ° C. for 5 days.

  After laminating the adhesive layer 2 and the barrier layer 3 on the base material layer 1 by the thermal lamination method, the adhesive layer 4 and the sealant layer 5 were laminated on the barrier layer 3 by the extrusion method. Specifically, after coating a solution in which 15% by weight of maleic acid-modified polypropylene is dispersed in a solvent on the side of the base material layer 1 on which the easy adhesion layer is formed, the solvent is dried to make the base material layer 1 easy. The adhesive layer 2 was laminated on the adhesive layer. Next, the barrier layer 3 is disposed on the adhesive layer 2 and laminated by heating with a hot roll so as to be 130 ° C. by a thermal lamination method, and the base layer 1 / adhesive layer 2 / barrier layer is laminated. 3 laminates were prepared. Next, the adhesive layer 4) and the sealant layer 5 are laminated on the barrier layer 3 of the laminate by a co-extrusion method, and heat treatment is performed at 190 ° C. for 5 seconds, whereby the base material layer 1 / adhesive layer 2 / barrier layer. A battery packaging material comprising a laminate in which 3 / adhesive layer 4 / sealant layer 5 were sequentially laminated was obtained.

Example 3
A battery packaging material comprising a laminate having a layer structure having the following composition was produced.
Base material layer 1 : biaxially stretched polyglycolic acid (thickness 25 μm) with silicon oxide deposited on one side
Adhesive layer 2 : maleic acid-modified polypropylene (thickness: 15 μm)
Barrier layer 3 : film formed using polyglycolic acid (thickness 50 μm)
Adhesive layer 4 : maleic acid-modified polypropylene (thickness: 15 μm)
Sealant layer 5 : random polypropylene (thickness 10 μm)

  The base material layer 1, the adhesive layer 2, the barrier layer 3, the adhesive layer 4, and the sealant layer 5 were laminated by a coextrusion lamination method. Specifically, the substrate layer 1 is laminated by a coextrusion lamination method so that the adhesive layer 2, the barrier layer 3, the adhesive layer 4, and the sealant layer 5 are sequentially laminated on the side on which the silicon oxide is deposited. By performing heat treatment at 190 ° C. for 5 seconds, a battery packaging material comprising a laminate in which base layer 1 / adhesive layer 2 / barrier layer 3 / adhesive layer 4 / sealant layer 5 were laminated in order was obtained.

Example 4
A battery packaging material comprising a laminate having a layer structure having the following composition was produced.
Base material layer 1 : biaxially stretched polyglycolic acid (thickness 25 μm) with silicon oxide deposited on one side
Adhesive layer 2 : maleic acid-modified polypropylene (thickness 5 μm)
Barrier layer 3 : film formed using polyglycolic acid (thickness 50 μm)
Adhesive layer 4 : maleic acid-modified polypropylene (thickness: 15 μm)
Sealant layer 5 : first layer made of random polypropylene (thickness 10 μm), second layer made of mixed resin (thickness 5 μm) of 70 parts by weight of polyglycolic acid and 30 parts by weight of random polypropylene, polyglycolic acid (thickness 15 μm) ), A fourth layer made of maleic acid-modified polypropylene (thickness 5 μm), and a fifth layer made of random polypropylene (thickness 10 μm).

  After laminating the adhesive layer 2 and the barrier layer 3 on the base material layer 1 by the thermal lamination method, the adhesive layer 4 and the sealant layer 5 were laminated on the barrier layer 3 by the sand lamination method. Specifically, after coating the substrate layer 1 on the side where silicon oxide is not deposited, a solution in which 15% by weight of maleic acid-modified polypropylene is dispersed in a solvent, the solvent is dried to form silicon oxide in the substrate layer. The adhesive layer 2 was laminated on the side on which no was deposited. Next, the barrier layer 3 is disposed on the adhesive layer 2 and laminated by heating with a hot roll so as to be 130 ° C. by a thermal lamination method, and the base layer 1 / adhesive layer 2 / barrier layer is laminated. 3 laminates were prepared. Next, the adhesive layer 4 is laminated on the barrier layer 3 of the laminate by the melt extrusion method, and at the same time, the sealant layer 5 is bonded and subjected to heat treatment at 190 ° C. for 5 seconds, whereby the base material layer 1 / A battery packaging material comprising a laminate in which adhesive layer 2 / barrier layer 3 / adhesive layer 4 / sealant layer 5 were laminated in order was obtained.

Example 5
A battery packaging material comprising a laminate having a layer structure having the following composition was produced.
Base material layer 1 : Polyglycolic acid (thickness 25 μm) having silicon oxide deposited on one surface
Adhesive layer 2 : Two-component urethane adhesive (thickness 4 μm) of polyester polyol (main agent) and toluene diisocyanate (curing agent)
Barrier layer 3 : film formed using polyglycolic acid (thickness 50 μm)
Adhesive layer 4 : mixed resin of 70 parts by weight of maleic acid-modified polypropylene and 30 parts by weight of polyglycolic acid
Sealant layer 5 : Mixed resin (thickness 35 μm) of 70 parts by weight of polyglycolic acid and 30 parts by weight of random polypropylene

  The adhesive layer 2, the barrier layer 3, and the adhesive layer 4 were laminated on the base material layer 1 by a coextrusion method, and the sealant layer 5 was laminated by a sand lamination method. Specifically, the adhesive layer 2, the barrier layer 3, and the adhesive layer 4 are laminated by the coextrusion method on the side on which the silicon oxide is deposited on the base material layer 1, and at the same time, the sealant layer 5 is bonded. By performing heat treatment at 5 ° C. for 5 seconds, a battery packaging material comprising a laminate in which the base material layer 1 / adhesive layer 2 / barrier layer 3 / adhesive layer 4 / sealant layer 5 were laminated in order was obtained.

Comparative Example 1
A battery packaging material comprising a laminate having a layer structure having the following composition was produced.
Base material layer 1 : Biaxially stretched polyamide (nylon 6, thickness 25 μm)
Adhesive layer 2 : Two-component urethane adhesive (thickness 4 μm) of polyester polyol (main agent) and toluene diisocyanate (curing agent)
Barrier layer 3 : Aluminum foil (40 μm thick) with chemical conversion treatment on both sides
Adhesive layer 4 : maleic acid-modified polypropylene (thickness: 15 μm)
Sealant layer 5 : film (thickness 30 μm) formed using random polypropylene

  In addition, the chemical conversion treatment of the aluminum foil used as the barrier layer 3 is performed by applying a treatment liquid composed of a phenol resin, a chromium fluoride compound, and phosphoric acid to both surfaces of the aluminum foil by a roll coating method, and the coating temperature is 180 ° C. or higher. It was performed by baking for 20 seconds under the following conditions.

  After laminating the adhesive layer 2 and the barrier layer 3 on the base material layer 1 by the dry lamination method, the adhesive layer 4 and the sealant layer 5 were laminated on the barrier layer 3 by the sand lamination method. Specifically, after applying the adhesive layer 2 on the base material layer 1 and pressurizing and heating with the barrier layer 3, the base material layer 1 / adhesion is carried out by performing an aging treatment at 60 ° C. for 24 hours. A layer 2 / barrier layer 3 laminate was prepared. Next, the adhesive layer 4 is laminated on the barrier layer 3 of the laminate by the melt extrusion method, and at the same time, the sealant layer 5 is bonded and subjected to heat treatment at 190 ° C. for 5 seconds, whereby the base material layer 1 / A battery packaging material comprising a laminate in which adhesive layer 2 / barrier layer 3 / adhesive layer 4 / sealant layer 5 were laminated in order was obtained.

Comparative Example 2
A battery packaging material comprising a laminate having a layer structure having the following composition was produced.
Base material layer 1 : Biaxially stretched polyethylene terephthalate (thickness 25 μm) having an easy-adhesion layer formed on one surface
Adhesive layer 2 : maleic acid-modified polypropylene (thickness 5 μm)
Barrier layer 3 : film formed using random polypropylene (thickness 50 μm)
Adhesive layer 4 : maleic acid-modified polypropylene (thickness: 15 μm)
Sealant layer 5 : Mixed resin (thickness 35 μm) of 70 parts by weight of polyglycolic acid and 30 parts by weight of random polypropylene

  Specifically, a battery packaging material was obtained under the same conditions as in Example 1 except that a film (thickness 50 μm) formed using random polypropylene was used as the barrier layer 3.

Test example: performance evaluation About each battery packaging material obtained above, durability with respect to electrolyte solution, water vapor | steam barrier property, short circuit property, and biodegradability were evaluated. A specific evaluation method is as follows.

[Evaluation of durability against electrolyte]
By performing plastic working using a mold, each battery packaging material was formed into a concave mold having a depth of 3 mm and a length and width of 50 mm × 35 mm. 3 g of the mixture having the composition shown below was sealed under a heat seal condition of 190 ° C., 2.0 MPa, 3.0 seconds with a seal width of 3 mm, and stored at 85 ° C. for 720 hours. After storage, the presence or absence of delamination of the barrier layer 3 and the sealant layer 5 in each battery packaging material was confirmed.
Composition of liquid mixture: A liquid mixture of ethylene carbonate, diethyl carbonate and dimethyl carbonate (1: 1: 1 by volume) containing 1M LiPF ₆ .

[Evaluation of water vapor barrier properties]
Each battery packaging material is used to make a packaging bag of 60 mm in length and 50 mm in length, filled with 3 g of a mixed solution containing ethylene carbonate, diethyl carbonate, and dimethyl carbonate in a volume ratio of 1: 1: 1, and sealed. Sealing conditions were 190 ° C., 2.0 M, 3.0 seconds, and sealed in three directions so that the width was 3 mm. This was stored in a constant temperature and humidity chamber at 60 ° C. and 90% RH for 10 days, and the amount of water increase in the mixed solution was measured by the Karl Fischer method.

[Short-circuit evaluation]
By performing plastic working using a mold, a concave molded product having a depth of 3 mm and a length and width of 50 mm × 35 mm was prepared from each battery packaging material. Next, after winding a lead wire film (thickness 50 μm) made of a predetermined material around a predetermined position of a lead wire (nickel, 100 μm thickness, 4 mm width, length 25 mm) of the battery body, After being inserted into a molded product and sandwiched so as to become a molded battery packaging material / lead wire / packaging material, the portion was heat-sealed at 190 ° C. and 2.0 MPa. Evaluation of short circuit property measured the time until the short circuit with a lead wire and the metal layer of the packaging material for batteries produced. The presence or absence of a short circuit is confirmed by a tester (judgment conditions: applied voltage 100 V, judgment resistance value 2000 MΩ), and by a cross-sectional photograph (optical microscope, magnification 200 times), the presence of contact between the lead wire, the battery packaging material, and the metal layer is confirmed. confirmed. In addition, the film for lead wires used the thing made from a carboxylic acid modified polypropylene.

[Evaluation of biodegradability]
The biodegradability of each battery packaging material in compost was tested according to the method described in ISO 14855, and the weight retention rate (%) of each battery packaging material after 60 days was measured.

[Evaluation results]
The obtained results are shown in Table 1. As a result, the battery packaging materials of Examples 1 to 5 in which the barrier layer 3 is formed of a resin containing polyglycolic acid have good resistance to an electrolytic solution, water vapor barrier properties, and insulation, and are demanded as battery packaging materials. It has been confirmed that it has the basic performance and biodegradability and can reduce the environmental load at the time of disposal. On the other hand, the battery packaging material of Comparative Example 1 using an aluminum foil as the barrier layer 3 was inferior to Examples 1 to 5 in insulation and did not have biodegradability. Furthermore, the battery packaging material of Comparative Example 2 using random polypropylene as the barrier layer 3 has insufficient water vapor barrier properties, does not have the basic performance required as a battery packaging material, and is also biodegradable. Did not have. The battery packaging materials of Examples 1 to 5 were lighter than Comparative Example 1 because no aluminum foil was used as the barrier layer 2.

1 Base material layer 2 Adhesive layer 3 Barrier layer 4 Adhesive layer 5 Sealant layer

Claims (5)

It consists of a laminate in which at least a base material layer, a barrier layer, and a sealant layer are sequentially laminated,
The barrier layer is formed of a resin layer containing a polyglycolic acid resin.
A battery packaging material characterized by the above.   The battery packaging material according to claim 1, wherein an adhesive layer is formed between the base material layer and the barrier layer and / or between the barrier layer and the sealant layer.   The battery packaging material according to claim 1 or 2, wherein a polyglycolic acid resin is contained in at least one of the base material layer and the sealant layer.   The battery packaging material according to any one of claims 1 to 3, which is a packaging material for a secondary battery.   The battery by which the battery element provided with the positive electrode, the negative electrode, and the electrolyte at least is accommodated in the battery packaging material in any one of Claims 1-4.