JP2015195089A - Battery-packaging material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery-packaging material having superior electrolyte resistance.SOLUTION: A battery-packaging material comprises a laminate having at least, a base material layer, an adhesive layer, a metal foil layer, and a sealant layer in this order. The battery-packaging material is arranged to have superior electrolyte resistance by providing an acid reaction resin layer including an acid-curable resin between the adhesive layer and the metal foil layer and/or between the metal foil layer and the sealant layer.

Description

  The present invention relates to a battery packaging material having excellent electrolytic solution resistance. Furthermore, the present invention relates to a battery packaging material that has excellent electrolytic solution resistance and also has excellent insulating properties.

  Conventionally, various types of batteries have been developed, and packaging materials are indispensable members for sealing battery elements such as electrodes and electrolytes in all batteries. Conventionally, metal packaging materials have been widely used as battery packaging, but in recent years, with the increasing performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, etc., batteries are required to have various shapes. At the same time, there is a demand for reduction in thickness and weight. 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.

  Therefore, in recent years, a film-like laminate in which a base material layer / adhesive layer / barrier layer / sealant layer are sequentially laminated as a battery packaging material that can be easily processed into various shapes and can be reduced in thickness and weight. Has been proposed (see, for example, Patent Document 1). Such a film-shaped battery packaging material is formed so that the battery element can be sealed by causing the sealant layers to face each other and heat-sealing the peripheral portion by heat sealing.

  In conventional film-like battery packaging materials, the barrier layer has a function of preventing the entry of water vapor, oxygen, light, etc. into the battery, in addition to improving the strength of the packaging material, and metal foil is often used. ing. Such a metal foil has characteristics that adhesion to other layers is low and layer peeling is likely to occur. In addition, water is usually not contained in the electrolytic solution, but when water is mixed into the electrolytic solution for some reason, hydrogen fluoride is generated, which may cause corrosion or dissolution of the metal foil. Therefore, conventionally, one or both surfaces of the metal foil laminated on the film-like battery packaging material has been provided with an electrolytic solution resistance by performing a chromate treatment, and the adhesion between the metal foil and other layers is performed. To prevent the corrosion and dissolution of metal foil. However, the required performance for film-like battery packaging materials is diversified, and development of a technique for improving the resistance to electrolytic solution by a method other than the chromate treatment of metal foil is desired.

  Also, in the battery manufacturing process, if minute foreign matter such as electrode active material or electrode tab fragments adheres to the surface of the sealant layer, the foreign matter comes into contact with the barrier layer due to heat and pressure during heat sealing, causing a short circuit. There is. For this reason, film-shaped battery packaging materials are required to maintain high insulating properties and improve safety even if such minute foreign matter is mixed. Therefore, development of a technique for combining excellent electrolytic solution resistance and insulation in a film-like battery packaging material is also desired.

JP 2001-202927 A

  An object of the present invention is to provide a battery packaging material having excellent electrolytic solution resistance. Furthermore, the other object of this invention is to provide the packaging material for batteries which has the outstanding electrolyte solution resistance and insulation.

  The inventors of the present invention conducted intensive studies to solve the above problems, and in the battery packaging material comprising at least a base material layer, an adhesive layer, a metal foil layer, and a sealant layer in this order, By providing an acid-reactive resin layer containing an acid-curable resin between the adhesive layer and the metal foil layer and / or between the metal foil layer and the sealant layer, it is possible to provide excellent electrolytic solution resistance. I found it possible. Furthermore, by providing the acid reaction resin layer with a thickness of 0.01 μm or more between the genus foil layer and the sealant layer, fine foreign substances adhere to the sealant layer while having excellent electrolytic solution resistance. It has also been found that high insulation can be maintained by preventing short circuit. The present invention has been completed by further studies based on such knowledge.

That is, this invention provides the invention of the aspect hung up below.
Item 1. It consists of a laminate having at least a base material layer, an adhesive layer, a metal foil layer, and a sealant layer in this order,
A battery packaging material comprising an acid-reactive resin layer containing an acid-curable resin between the adhesive layer and the metal foil layer and / or between the metal foil layer and the sealant layer. .
Item 2. Item 2. The battery packaging material according to Item 1, wherein the acid-reactive resin layer is provided at least between the metal foil layer and the sealant layer.
Item 3. Item 3. The battery packaging material according to Item 1 or 2, wherein the acid curable resin is an acid curable furan resin and / or an acid curable phenol resin.
Item 4. Item 4. The battery packaging material according to any one of Items 1 to 3, wherein the acid-reactive resin layer has a thickness of 0.01 µm or more.
Item 5. Item 5. The battery packaging material according to any one of Items 1 to 4, wherein the metal foil layer is an aluminum foil.
Item 6. A method for producing a battery packaging material including the following steps:
A first step of forming a laminate in which an acid-reactive resin layer containing an acid-curable resin is laminated on at least one surface of the metal foil layer;
A second step of forming a laminate in which a base material layer is laminated on the laminate obtained in the first step via an adhesive layer, and a base material layer of the laminate obtained in the second step A third step of laminating a sealant layer on the opposite surface.
Item 7. The battery in which the battery element provided with at least the positive electrode, the negative electrode, and the electrolyte is accommodated in the battery packaging material according to any one of Items 1 to 5.

  The battery packaging material of the present invention is a laminate having at least a base material layer, an adhesive layer, a metal foil layer, and a sealant layer in this order, and between the adhesive layer and the metal foil layer and / or the metal foil layer. And an acid reaction resin layer containing an acid curable resin is provided between the sealant layer and the sealant layer. When the acid-reactive resin layer is not in contact with an acid, an uncured acid-curable resin remains.However, when an acid such as hydrogen fluoride is generated by mixing water in the electrolyte, Since the uncured acid-curable resin contained in the acid-reactive resin layer is cured to enhance the barrier function against the acid, the corrosion and dissolution of the metal foil layer can be effectively prevented. Furthermore, when the acid-reactive resin layer comes into contact with an acid, the adhesiveness is improved by curing the uncured acid-curable resin, so that it is possible to suppress a decrease in the adhesive strength due to the electrolytic solution.

  In the battery packaging material of the present invention, the acid-reactive resin layer has appropriate elasticity due to the presence of at least a part of the acid-curable resin in an uncured state. However, cracks are hardly generated and minute foreign objects are difficult to penetrate. Therefore, in the battery packaging material of the present invention, by providing the acid-reactive resin layer having a thickness of 0.01 μm or more between the metal foil layer and the sealant layer, heat is generated in a state where minute foreign matters are attached to the sealant layer. Even if it seals, it can suppress that a micro foreign material penetrates to the said metal foil layer, and can maintain high insulation.

  Furthermore, in the present invention, since the acid-reactive resin layer can provide excellent electrolytic solution resistance, a battery packaging material using a metal foil layer not subjected to chromate treatment is provided. Therefore, it is possible to avoid the use of chromium, which causes environmental pollution, and to contribute to the reduction of the environmental load.

It is a figure which shows an example of the cross-section of the packaging material for batteries of this invention. 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 having at least a base material layer, an adhesive layer, a metal foil layer, and a sealant layer in this order, and is between the adhesive layer and the metal foil layer and / or the adhesive layer. An acid reaction resin layer containing an acid curable resin is provided between the sealant layer and the sealant layer. 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 of the present invention has a laminated structure comprising at least a base material layer 1, an adhesive layer 2, a metal foil layer 3, and a sealant layer 4 in this order, An acid reaction resin layer 5 is provided between the adhesive layer 2 and the metal foil layer 3 and / or between the metal foil layer 3 and the sealant layer 4.

  In the battery packaging material of the present invention, the acid-reactive resin layer 5 only needs to be provided either between the adhesive layer 2 and the metal foil layer 3 or between the metal foil layer 3 and the sealant layer 4. However, it is preferable that at least between the metal foil layer 3 and the sealant layer 4 is provided from the viewpoint of providing more excellent electrolytic solution resistance, and between the adhesive layer 2 and the metal foil layer 3 and the metal foil. More preferably, it is provided both between the layer 3 and the sealant layer 4. Moreover, when providing the battery packaging material of this invention with the outstanding insulation, it is required to provide at least between the metal foil layer 3 and the sealant layer 4. FIG. 1 shows an embodiment in which an acid-reactive resin layer 5 is provided between a metal foil layer 3 and a sealant layer 4 as an example of a cross-sectional structure of the battery packaging material of the present invention. In FIG. 2, as an example of the cross-sectional structure of the battery packaging material of the present invention, the acid-reactive resin layer 5 is provided between the adhesive layer 2 and the metal foil layer 3 and between the metal foil layer 3 and the sealant layer 4. It shows about the aspect provided.

  Moreover, in the battery packaging material of the present invention, an adhesive layer 6 may be provided on the base material layer 1 side of the sealant layer 4 as necessary for the purpose of improving the adhesiveness of the sealant layer 4.

  In the battery packaging material of the present invention, the base material layer 1 is the outermost layer and the sealant layer 4 is the innermost layer. When assembling the battery, the sealant layers 4 located on the periphery of the battery element are brought into contact with each other and thermally welded to seal the battery element and seal the battery element.

2. Composition of each layer forming battery packaging material [acid reaction resin layer 5]
In the battery packaging material of the present invention, the acid reaction resin layer 5 is a layer provided between the adhesive layer 2 and the metal foil layer 3 and / or between the metal foil layer 3 and the sealant layer 4. The acid reaction resin layer 5 is formed of an acid curable resin. Thus, by using the acid curable resin and providing the acid-reactive resin layer 5 between the adhesive layer 2 and the metal foil layer 3 and / or between the metal foil layer 3 and the sealant layer 4, excellent resistance to resistance is obtained. It becomes possible to provide electrolyte properties. Furthermore, when the acid reaction resin layer 5 is provided between the metal foil layer 3 and the sealant layer 4, in addition to excellent electrolytic solution resistance, insulation can also be improved.

  The acid curable resin is a resin having a property of being cured by polycondensation with an acid. Although it does not restrict | limit especially about the kind of acid curable resin used by this invention, For example, an acid curable furan resin, an acid curable phenol resin, etc. are mentioned.

  Specific examples of the acid curable furan resin include furfuryl alcohol, condensate of furfuryl alcohol, condensate of furfuryl alcohol and aldehydes, condensate of furfuryl alcohol and urea, furfuryl alcohol and phenols. And a condensate of furfuryl alcohol, melamine, and aldehydes, a condensate of furfuryl alcohol, urea, and aldehydes. These acid-curable furan resins may be used alone or in combination of two or more.

  Examples of the aldehydes condensed with furfuryl alcohol include formaldehyde, acetaldehyde, glyoxal, furfural, terephthalaldehyde, and the like. These aldehydes may be used individually by 1 type, and may be used in combination of 2 or more type.

  Examples of the phenols condensed with furfuryl alcohol include phenol, cresol, resorcin, bisphenol A, bisphenol C, bisphenol E, bisphenol F, and the like. These phenols may be used individually by 1 type, and may be used in combination of 2 or more type.

  The acid curable phenolic resin may be either a novolak type or a resol type. An acid curable phenol resin may be used individually by 1 type, and may be used in combination of 2 or more type.

  These acid curable resins may be used individually by 1 type, and may be used in combination of 2 or more type. Among these acid curable resins, from the viewpoint of providing more excellent electrolytic solution resistance and insulation, preferably a thermosetting furan resin, more preferably a condensate of furfuryl alcohol and urea, furfuryl. Examples include urea-modified furan resins such as condensates of alcohol, urea, and aldehydes.

  In the acid reaction resin layer 5, the acid curable resin may be in a partially cured state as long as at least a part thereof is contained in an uncured state. Thus, when at least a part of the acid curable resin exists in an uncured state, it can be cured when brought into contact with the acid generated in the electrolytic solution, and can have excellent electrolytic solution resistance. In addition, since at least a part of the acid curable resin is in an uncured state, the acid-reactive resin layer 5 has appropriate elasticity, hardly cracks even when the fine foreign matter is pressed in, and the fine foreign matter is not present. Since it is difficult to penetrate, even if heat-sealing is performed in a state where the minute foreign matter adheres to the sealant layer 4 by providing the acid reaction resin layer 5 between the metal foil layer 3 and the sealant layer 4, the minute foreign matter is not Penetration to the metal foil layer 3 can be suppressed and high insulation can be maintained.

  In order for the acid-reactive resin layer 5 to be present in a state in which a part of the acid-curable resin is cured, the acid-curable resin may be applied to a predetermined portion and then heat-treated. The conditions for the heat treatment may be appropriately set according to the type of acid curable resin to be used, the degree of curing, and the like. For example, 120 to 250 ° C., preferably 150 to 200 ° C., and 0.1 to 60 seconds. , Preferably 1-30 seconds are mentioned.

  The thickness of the acid reaction resin layer 5 is, for example, 0.005 μm or more, preferably 0.01 μm or more, more preferably 1 μm or more, still more preferably 3 μm or more, and particularly preferably 3 μm or more. The upper limit of the thickness of the acid reaction resin layer 5 is not particularly limited, and for example, 7 μm, preferably 5 μm can be mentioned. Moreover, when the acid reaction resin layer 5 is provided between the metal foil layer 3 and the sealant layer 4 to provide excellent electrolytic solution resistance and excellent insulation, the thickness of the acid reaction resin layer 5 is 0.01 μm or more, preferably 0.9 μm or more, more preferably 1 to 7 μm, still more preferably 3 to 7 μm, and particularly preferably 3 to 5 μm.

[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, polyamide, epoxy, acrylic, fluororesin, polyurethane, silicon resin, phenol, polyetherimide, polyimide, and a mixture or copolymer thereof.

  Specific examples of the polyester include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, copolymerized polyester mainly composed of ethylene terephthalate, and repeating units of butylene terephthalate. Copolyester etc. mainly composed of The copolymer polyester mainly composed of ethylene terephthalate is a copolymer polyester that polymerizes with ethylene isophthalate mainly composed of ethylene terephthalate (hereinafter, polyethylene (terephthalate / isophthalate)). Abbreviated), polyethylene (terephthalate / isophthalate), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate) And polyethylene (terephthalate / decanedicarboxylate). In addition, as a copolymer polyester mainly composed of butylene terephthalate as a repeating unit, specifically, a copolymer polyester that polymerizes with butylene isophthalate having butylene terephthalate as a repeating unit (hereinafter referred to as polybutylene (terephthalate / isophthalate)). For example), polybutylene (terephthalate / adipate), polybutylene (terephthalate / sebacate), polybutylene (terephthalate / decanedicarboxylate), polybutylene naphthalate and the like. These polyesters may be used individually by 1 type, and may be used in combination of 2 or more type. Polyester has the advantage of being excellent in electrolytic solution resistance and less likely to cause whitening due to the adhesion of the electrolytic solution, and is suitably used as a material for forming the base material layer 1.

  Specific examples of the polyamides include aliphatic polyamides such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, and a copolymer of nylon 6 and nylon 6,6; terephthalic acid and / or Or hexamethylenediamine-isophthalic acid-terephthalic acid copolymerized polyamide, polymer, such as nylon 6I, nylon 6T, nylon 6IT, nylon 6I6T (I represents isophthalic acid, T represents terephthalic acid) containing structural units derived from isophthalic acid Polyamides containing aromatics such as taxylylene adipamide (MXD6); Alicyclic polyamides such as polyaminomethylcyclohexyl adipamide (PACM6); and isocyanate components such as lactam components and 4,4′-diphenylmethane-diisocyanate Copolymerized polyamide, Polyester amide copolymer and polyether ester amide copolymer is a copolymer of polymerized polyamide and polyester and polyalkylene ether glycol; copolymers thereof, and the like. These polyamides may be used individually by 1 type, and may be used in combination of 2 or more type. The stretched polyamide film is excellent in stretchability, can prevent whitening due to resin cracking of the base material layer 1 during molding, and is suitably used as a material for forming the base material layer 1.

  The base material layer 1 may be formed of a uniaxially or biaxially stretched resin film, or may be formed of an unstretched resin film. Among them, a uniaxially or biaxially stretched resin film, in particular, a biaxially stretched resin film has improved heat resistance by orientation crystallization, and thus is suitably used as the base material layer 1.

  Among these, as a resin film which forms the base material layer 1, Preferably nylon and polyester, More preferably, biaxially stretched nylon, biaxially stretched polyester, Most preferably, biaxially stretched polyester is mentioned.

  The base material layer 1 can also be laminated with resin films of different materials in order to improve pinhole resistance and insulation when used as a battery package. Specific examples include a multilayer structure in which a polyester film and a nylon film are laminated, and a multilayer structure in which a biaxially stretched polyester and a biaxially stretched nylon are laminated. When making the base material layer 1 into a multilayer structure, each resin film may be adhere | attached through an adhesive agent, and may be laminated | stacked directly without an adhesive agent. In the case of bonding without using an adhesive, for example, a method of bonding in a hot melt state such as a co-extrusion method, a sand lamination method, or a thermal laminating method can be mentioned.

  Further, the base material layer 1 may be made to have low friction in order to improve moldability. In the case of reducing the friction of the base material layer 1, the friction coefficient of the surface is not particularly limited, but for example, 1.0 or less can be mentioned. In order to reduce the friction of the base material layer 1, for example, mat treatment, formation of a thin film layer of a slip agent, a combination thereof, and the like can be given.

  As the matting treatment, a matting agent is added to the base material layer 1 in advance to form irregularities on the surface, a transfer method by heating or pressurizing with an embossing roll, a surface is mechanically dry or wet blasting or filed. The method of ruining is mentioned. Examples of the matting agent include fine particles having a particle size of about 0.5 nm to 5 μm. The material of the matting agent is not particularly limited, and examples thereof include metals, metal oxides, inorganic substances, and organic substances. The shape of the matting agent is not particularly limited, and examples thereof include a spherical shape, a fiber shape, a plate shape, an indeterminate shape, and a balloon shape. As a matting agent, specifically, talc, silica, graphite, kaolin, montmorilloid, montmorillonite, synthetic mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, oxidation Aluminum, neodymium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, alumina, carbon black, carbon nanotubes , High melting point nylon, crosslinked acrylic, crosslinked styrene, crosslinked polyethylene, benzoguanamine, gold, aluminum, copper, nickel and the like. These matting agents may be used individually by 1 type, and may be used in combination of 2 or more type. Among these matting agents, silica, barium sulfate, and titanium oxide are preferable from the viewpoint of dispersion stability and cost. The matting agent may be subjected to various surface treatments such as insulation treatment and high dispersibility treatment on the surface noodles.

  The slip agent thin film layer can be formed by depositing a slip agent on the surface of the base material layer 1 by bleeding out to form a thin layer, or by laminating the slip agent on the base material layer 1. The slip agent is not particularly limited. For example, fatty acid amide, metal soap, hydrophilic silicone, silicone grafted acrylic, silicone grafted epoxy, silicone grafted polyether, silicone grafted polyester, block silicone Examples thereof include acrylic copolymers, polyglycerol-modified silicone, and paraffin. These slip agents may be used individually by 1 type, and may be used in combination of 2 or more type.

  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 disposed on the base material layer 1 in order to impart adhesion to the base material layer 1. That is, when the acid reaction resin layer 5 is provided on the base material layer 1 side of the metal foil layer 3, the adhesive layer 2 is provided between the base material layer 1 and the acid reaction resin layer 5. When the acid reaction resin layer 5 is not provided on the base material layer 1 side of the metal foil layer 3, the adhesive layer 2 is provided between the base material layer 1 and the metal foil layer 3.

  The adhesive layer 2 is formed of an adhesive capable of adhering the base material layer 1 and the acid reaction resin layer 5 or the metal foil layer 3. The adhesive used for forming the adhesive layer 2 may be a two-component curable adhesive or a one-component curable adhesive. Also, the adhesive 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, and a hot pressure type.

  Specific examples of the resin component of the adhesive that can be used to form the adhesive layer 2 include polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, and copolyester. Resin; Polyether adhesive; Polyurethane adhesive; Epoxy resin; Phenol resin resin; Polyamide resin such as nylon 6, nylon 66, nylon 12, copolymer polyamide; polyolefin, acid-modified polyolefin, metal-modified polyolefin, etc. Polyolefin resin; polyvinyl acetate resin; cellulose adhesive; (meth) acrylic resin; polyimide resin; urea resin, melamine resin and other amino resins; chloroprene rubber, nitrile rubber, styrene - rubbers such as butadiene rubber, silicone resin; fluorinated ethylene propylene copolymer, and the like. These adhesive components may be used individually by 1 type, and may be used in combination of 2 or more type. The combination mode of two or more kinds of adhesive components is not particularly limited. For example, as the adhesive component, a mixed resin of polyamide and acid-modified polyolefin, a mixed resin of polyamide and metal-modified polyolefin, polyamide and polyester, Examples thereof include a mixed resin of polyester and acid-modified polyolefin, and a mixed resin of polyester and metal-modified polyolefin. Among these, extensibility, durability under high humidity conditions, anti-hypertensive action, thermal deterioration-preventing action during heat sealing, etc. are excellent, and a decrease in the lamination strength between the base material layer 1 and the metal layer 2 is suppressed. From the viewpoint of effectively suppressing the occurrence of delamination, a polyurethane two-component curable adhesive; polyamide, polyester, or a blended resin of these with a modified polyolefin is preferable.

  The adhesive layer 2 may be multilayered with different adhesive components. When the adhesive layer 2 is multilayered with different adhesive components, from the viewpoint of improving the lamination strength between the base material layer 1 and the metal foil layer 3, the adhesive component disposed on the base material layer 1 side is used as the base material layer. It is preferable to select a resin excellent in adhesiveness with 1, and select an adhesive component excellent in adhesiveness with the metal foil layer 3 as an adhesive component disposed on the metal foil layer 3 side. When the adhesive layer 2 is multilayered with different adhesive components, specifically, the adhesive component disposed on the metal foil layer 3 side is preferably acid-modified polyolefin, metal-modified polyolefin, polyester and acid-modified polyolefin. And mixed resins, resins containing copolymerized polyesters, and the like.

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

[Metal foil layer 3]
In the battery packaging material of the present invention, the metal foil layer 3 is a layer that functions as a barrier layer for preventing moisture, oxygen, light, and the like from entering the battery, in addition to improving the strength of the packaging material. Specific examples of the metal forming the metal foil layer 3 include metal foils such as aluminum, stainless steel, and titanium. Among these, aluminum is preferably used. In order to prevent wrinkles and pinholes during the production of the packaging material, soft aluminum, for example, annealed aluminum (JIS A8021P-O) or (JIS A8079P-O) is used as the metal foil layer 3 in the present invention. It is preferable.

  The thickness of the metal foil layer 3 is, for example, 10 to 200 μm, preferably 20 to 100 μm.

  In the battery packaging material of the present invention, the metal foil layer 3 does not need to be subjected to chromate treatment because it has excellent electrolytic solution resistance by providing the acid reaction resin layer 5. When avoiding the use of chromium, which causes environmental pollution, and placing importance on reducing the environmental burden, the metal foil layer 3 that has not been subjected to chromate treatment may be used. May use the metal foil layer 3 subjected to the chromate treatment.

  Examples of chromate treatment include chromate chromate using chromic acid compounds such as chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium biphosphate, chromic acid acetyl acetate, chromium chloride, and potassium sulfate chromium. Treatment; Phosphoric acid chromate treatment using a phosphoric acid compound such as sodium phosphate, potassium phosphate, ammonium phosphate, polyphosphoric acid; aminated phenol having a repeating unit represented by the following general formulas (1) to (4) Examples include chromate treatment using a polymer.

In general formulas (1) to (4), X represents a hydrogen atom, a hydroxyl group, an alkyl group, a hydroxyalkyl group, an allyl group or a benzyl group. R ¹ and R ² are the same or different and each represents a hydroxyl group, an alkyl group, or a hydroxyalkyl group. In the general formulas (1) to (4), examples of the alkyl group represented by X, R ¹ and R ² include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, C1-C4 linear or branched alkyl groups, such as a tert- butyl group, are mentioned. Examples of the hydroxyalkyl group represented by X, R ¹ and R ² include a hydroxymethyl group, a 1-hydroxyethyl group, a 2-hydroxyethyl group, a 1-hydroxypropyl group, a 2-hydroxypropyl group, 3- C1-C4 straight or branched chain in which one hydroxy group such as hydroxypropyl group, 1-hydroxybutyl group, 2-hydroxybutyl group, 3-hydroxybutyl group, 4-hydroxybutyl group is substituted An alkyl group is mentioned. In the general formulas (1) to (4), the alkyl group and hydroxyalkyl group represented by X, R ¹ and R ² may be the same or different. In the general formulas (1) to (4), X is preferably a hydrogen atom, a hydroxyl group or a hydroxyalkyl group. The number average molecular weight of the aminated phenol polymer having the repeating units represented by the general formulas (1) to (4) is preferably, for example, 500 to 1,000,000, more preferably about 1,000 to 20,000. preferable.

The amount of the acid-resistant film formed on the surface of the metal foil layer 3 in the chromate treatment is not particularly limited. For example, the chromic acid compound is about 0.5 mg to about 0.5 mg in terms of chromium per 1 m ² of the surface of the metal foil layer 3. 50 mg, preferably about 1.0 mg to about 40 mg, phosphorus compound in terms of phosphorus is about 0.5 mg to about 50 mg, preferably about 1.0 mg to about 40 mg, and aminated phenol polymer is about 1 mg to about 200 mg, preferably Is preferably contained at a ratio of about 5.0 mg to 150 mg.

  In the chromate treatment, a solution containing a compound used for forming an acid-resistant film is applied to the surface of the metal foil layer 3 by a bar coating method, a roll coating method, a gravure coating method, a dipping method or the like, and then the metal foil layer 3 It is performed by heating so that the temperature of is about 70 ° C to 200 ° C. Further, before the chromate treatment is performed on the metal foil layer 3, the gold metal foil layer 3 may be previously subjected to a degreasing treatment by an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, or the like. By performing the degreasing process in this manner, it is possible to more efficiently perform the chromate process on the surface of the metal foil layer 3.

  Furthermore, the metal foil layer 3 may be subjected to a chemical conversion treatment that imparts corrosion resistance, if necessary. As a chemical conversion treatment method for imparting corrosion resistance to the metal foil layer 3, specifically, metal oxide such as aluminum oxide, titanium oxide, cerium oxide, tin oxide, or barium sulfate fine particles is dispersed in phosphoric acid. A method of forming a corrosion-resistant treatment layer on the surface of the metal layer 3 by coating is performed and baking treatment is performed at 150 ° C. or higher. Further, a resin layer obtained by crosslinking a cationic polymer with a crosslinking agent may be further formed on the corrosion-resistant treatment layer. Here, examples of the cationic polymer include polyethyleneimine, an ionic polymer complex composed of a polymer having polyethyleneimine and a carboxylic acid, a primary amine graft acrylic resin obtained by graft polymerization of a primary amine on an acrylic main skeleton, and polyallylamine. Or the derivative, aminophenol, etc. are mentioned. As these cationic polymers, only one type may be used, or two or more types may be used in combination. Examples of the crosslinking agent include a compound having at least one functional group selected from the group consisting of an isocyanate group, a glycidyl group, a carboxyl group, and an oxazoline group, a silane coupling agent, and the like. As these crosslinking agents, only one type may be used, or two or more types may be used in combination.

[Adhesive layer 6]
In the battery packaging material of the present invention, the adhesive layer 6 is a layer provided as needed on the base material layer 1 side of the sealant layer 4 in order to firmly adhere the sealant layer 4. That is, when the acid reaction resin layer 5 is provided on the sealant layer 4 side of the metal foil layer 3, the adhesive layer 6 is provided between the acid reaction resin layer 5 and the sealant layer 4. When the acid reaction resin layer 5 is not provided on the sealant layer 4 side of the metal foil layer 3, the adhesive layer 6 is provided between the metal foil layer 3 and the sealant layer 4.

  The adhesive layer 6 is formed of an adhesive capable of adhering the acid reaction resin layer 5 or the metal foil layer 3 and the sealant layer 4. Although there is no restriction | limiting in particular about the composition of the adhesive agent used for formation of the contact bonding layer 6, For example, the resin composition containing a thermosetting resin is mentioned. Specific examples of the thermosetting resin used for the adhesive layer 6 are the same as those exemplified for the adhesive layer 2.

  About the thickness of the contact bonding layer 6, 1-40 micrometers is mentioned, for example, Preferably 2-30 micrometers is mentioned.

[Sealant layer 4]
In the battery packaging material of the present invention, the sealant layer 4 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 for the sealant layer 4 is not particularly limited as long as it can be thermally welded, and examples thereof include polyolefin, cyclic polyolefin, carboxylic acid-modified polyolefin, and carboxylic acid-modified cyclic polyolefin.

  Specific examples of the polyolefin include polyethylene such as low density polyethylene, medium density polyethylene, high density polyethylene, and linear low density polyethylene; homopolypropylene, polypropylene block copolymer (for example, block copolymer of propylene and ethylene), polypropylene Crystalline polypropylene or amorphous polypropylene such as a random copolymer of propylene and ethylene; an ethylene-butene-propylene terpolymer; and the like. Among these polyolefins, polyethylene and polypropylene are preferable.

  The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer, and examples of the olefin that is a constituent monomer of the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, and isoprene. Is mentioned. 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. Among these polyolefins, cyclic alkene is preferable, and norbornene is more preferable.

  The carboxylic acid-modified polyolefin is a polymer obtained by modifying the polyolefin with a carboxylic acid. 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 is 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 with respect to the cyclic polyolefin. -A polymer obtained by block polymerization or graft polymerization of an unsaturated carboxylic acid or its anhydride. The cyclic polyolefin 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 acid-modified cycloolefin copolymer.

  Among these resin components, preferably a crystalline or amorphous polyolefin, a cyclic polyolefin, and a blend polymer thereof; more preferably polyethylene, polypropylene, a copolymer of ethylene and norbornene, and two or more of these The blend polymer of these is mentioned.

  The sealant layer 4 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. Furthermore, the sealant layer may be formed of only one layer, but may be formed of two or more layers using the same or different resin components.

  Further, the thickness of the sealant layer 4 is not particularly limited, but may be 2 to 2000 μm, preferably 5 to 1000 μm, and more preferably 10 to 500 μm.

3. Production method of battery packaging material The production method of the battery packaging material of the present invention is not particularly limited as long as a laminate in which layers of a predetermined composition are laminated is obtained. For example, the following first step to first step A method comprising three steps is illustrated:
A first step of forming a laminate in which the acid reaction resin layer 5 is laminated on at least one surface of the metal foil layer 3 (hereinafter also referred to as “laminate A”);
A second step of forming a laminate in which the base material layer 1 and the laminate A are laminated via the adhesive layer 2 (hereinafter also referred to as “laminate B”), and the base of the laminate B A third step of laminating a sealant layer 5 on the surface opposite to the material layer 1;

  Specifically, the formation of the laminate A in the first step is performed by applying a resin component constituting the acid reaction resin layer 5 on one surface or both surfaces of the metal foil layer by a method such as a gravure coating method or a roll coating method. This is done by applying. When a part of the acid curable resin is cured in the acid reaction resin layer 5, heat treatment may be performed under the above-described conditions after the application. In addition, when a dry laminating method is adopted in the second step described later, the acid curable resin in the acid-reactive resin layer 5 can be obtained by the heat treatment performed in the second step without performing the heat treatment in the first step. Can be cured.

  Specifically, the formation of the laminated body B in the second step is performed by curing the adhesive in a state where the base material layer 1 and the laminated body B are bonded to each other through the adhesive used for forming the adhesive layer 2. Is done. For example, if the laminate B is formed by a dry laminate method, an adhesive used for forming the adhesive layer 2 on the base material layer 1 or the laminate B is a gravure coat method, a roll coat method, or the like. After applying and drying by the application method, the laminate B or the base material layer 1 may be laminated and heat treatment may be performed. The conditions for the heat treatment may be appropriately set according to the type of resin component of the adhesive, etc., for example, 25 to 100 ° C., preferably 30 to 80 ° C., 1 to 10 days, preferably 2 to 7 Day.

  If the adhesive layer 6 is not provided in the third step, the resin component constituting the sealant layer 5 is applied to the surface of the laminate B opposite to the base material layer 1 by a gravure coating method or a roll coating method. What is necessary is just to apply | coat by methods, such as. If the adhesive layer 6 is provided, the third step includes, for example, (1) co-extrusion of the adhesive layer 6 and the sealant layer 5 on the surface of the laminate B opposite to the base material layer 1. (2) Separately, a laminate in which the adhesive layer 6 and the sealant layer 5 are laminated is formed on the surface of the laminate B opposite to the base material layer 1. (3) Laminate B is dried or baked at a high temperature on which the adhesive for forming adhesive layer 6 is formed by extrusion or solution coating on the opposite side of base material layer 1 of laminate B A method of laminating the sealant layer 5 which has been laminated by a method or the like and formed into a sheet on the adhesive layer 6 in advance by a thermal lamination method; (4) a surface of the laminate B opposite to the base material layer 1; Adhesive layer between sealant layer 5 previously formed into a sheet shape A method of bonding the surface of the laminate B opposite to the base material layer 1 and the sealant layer 5 through the adhesive layer 6 while pouring the adhesive for forming the adhesive 6 in a molten state (sand lamination method) Etc.

  As described above, the substrate layer 1, the adhesive layer 2, the metal foil layer 3, and the sealant layer 4 are provided in this order, and between the adhesive layer 2 and the metal foil layer 3, and / or the metal foil layer 3 and the sealant. A laminate having an acid reaction resin layer is formed between the layers 4.

  In the battery packaging material of the present invention, each layer constituting the laminate improves or stabilizes film forming properties, lamination processing, suitability for final processing (pouching, embossing), etc., as necessary. Therefore, surface activation treatment such as corona treatment, blast treatment, oxidation treatment, ozone treatment may be performed.

4). 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.

1. Manufacture of battery packaging materials
Examples 1-7
Urea-modified furan resin (HP6200N, manufactured by Asahi Organic Materials Co., Ltd.) is finally formed on one surface of a metal foil layer made of an aluminum foil (thickness 40 μm) that has not been subjected to chromate treatment so as to have a film thickness shown in Table 1. Was applied by roll coating, and heated at 190 ° C. for 3 seconds to form an acid-reactive resin layer on the metal foil layer. Next, after applying an adhesive layer composed of a two-component urethane adhesive of a polyester-based main agent and an isocyanic curing agent on the surface opposite to the acid-reactive resin layer of the metal foil layer to a thickness of 3 μm A base material layer made of a biaxially stretched nylon film (thickness 25 μm) was laminated by a dry lamination method to prepare a base material layer / adhesive layer / metal foil layer (no chromate treatment) / acid reaction resin layer laminate. .

  Subsequently, a carboxylic acid-modified polypropylene (arranged on the metal foil layer side, thickness 23 μm) and homopolypropylene (innermost layer, thickness 23 μm) are co-extruded on the acid-reactive resin layer of the laminate to form a metal. A two-layer sealant layer was laminated on the foil layer. Thus, a battery packaging material comprising a laminate in which a base material layer / adhesive layer / metal foil layer (no chromate treatment) / acid reaction resin layer / sealant layer were laminated in order was obtained.

Examples 8-14
Substrate layer / adhesive layer / metal foil layer (with chromate treatment) under the same conditions as in Example 1 except that a metal foil layer having a chromate treatment on both sides of an aluminum foil (thickness 40 μm) was used. A battery packaging material comprising a laminate in which / acid reaction resin layer / sealant layer was laminated in order was obtained. For chromate treatment, a treatment solution comprising a phenol resin, a chromium fluoride compound, and phosphoric acid is applied to both surfaces of the aluminum foil by a roll coating method so that the amount of chromium applied is 10 mg / m ² (dry weight). The film was baked for 20 seconds under the condition that the film temperature was 180 ° C. or higher. The acid-resistant film formed by the chromate treatment had a thickness (one side thickness) of 0.005 μm.

Comparative Example 1
A battery comprising a laminate in which a base material layer / adhesive layer / metal foil layer (no chromate treatment) / sealant layer are sequentially laminated under the same conditions as in Example 1 except that the acid-reactive resin layer is not provided. Packaging material was obtained.

Comparative Example 2
It consists of a laminate in which a base material layer / adhesive layer / metal foil layer (with chromate treatment) / sealant layer are laminated in order under the same conditions as in Example 8 except that the acid-reactive resin layer is not provided. A battery packaging material was obtained.

2. Evaluation of battery packaging materials <Evaluation of electrolyte resistance>
The battery packaging materials were each cut into 60 mm (MD direction, vertical direction) × 150 mm (TD direction, horizontal direction). Next, the cut battery packaging material is folded in half so that the sealant layers face each other in the TD direction, one side in the TD direction and one side in the MD direction are thermally welded, and one side in the TD direction is An open bag-shaped battery packaging material was prepared. The heat welding conditions were a temperature of 190 ° C., a surface pressure of 1.0 MPa, and a heating / pressurization time of 3 seconds. Next, 3 g of electrolytic solution was injected from the opening, and the opening was 7 mm wide and thermally welded under the same conditions as described above. The electrolytic solution was obtained by mixing lithium hexafluorophosphate with a solution mixed at a volume ratio of ethylene carbonate: diethyl carbonate: dimethyl carbonate = 1: 1: 1. Next, the part where the opening part of the packaging material for batteries was located was faced up, and it left still in an 85 degreeC thermostat for 24 hours.

Next, each battery packaging material was taken out from the thermostatic layer, the battery packaging material was opened, and the electrolytic solution was taken out. Thereafter, the folded portion of the battery packaging material was cut into a 15 mm wide strip to obtain a test piece. Using a tensile machine (trade name AGS-50D manufactured by Shimadzu Corporation), the sealant layer and the metal layer of the obtained test piece were pulled at a speed of 50 mm / min, and the peel strength (N / 15 mm) of the test piece was measured. (Peel strength after durability test). The peel strength of the test piece obtained by cutting the battery packaging material to a width of 15 mm was measured in the same manner (peel strength before the durability test). From the obtained peel strength values before and after the durability test, the peel strength remaining rate (%) was calculated according to the following formula.
Peel strength remaining rate (%) = (Peel strength after durability test / Peel strength before durability test) × 100

<Insulation evaluation against minute foreign object biting>
The battery packaging material was cut into a size of 40 mm in width and 100 mm in length to obtain a test piece. Next, the test piece was folded so that the short sides were opposed to each other, and the surfaces of the sealant layers of the test pieces were arranged so as to face each other. Next, a 25 μmφ wire was inserted between the surfaces of the sealant layers facing each other. Next, in this state, the sealant layers were heat-sealed with a heat-sealing machine composed of a plate-like hot plate having a width of 7 mm in both the upper and lower directions in a direction perpendicular to the length direction of the battery packaging material (heat seal condition: 190 ° C., 1 0.0 MPa). Next, the terminals of the tester were connected to the surfaces of the base material layers on both sides so that the portion where the wire of the battery packaging material was sandwiched was in the center. Next, a voltage of 100 V was applied between the testers, and the time (seconds) until short-circuiting was measured.

<Evaluation results>
The obtained results are shown in Table 1. From this result, it was confirmed that by providing an acid-reactive resin layer between the metal foil layer and the sealant layer, the electrolytic solution resistance and the insulation against minute foreign matter biting are dramatically improved. Furthermore, it becomes clear that by providing an acid-reactive resin layer having a thickness of 0.01 μm or more, particularly 1 μm or more, and using a metal foil layer that has been subjected to a chromate treatment, it has a further excellent resistance to electrolytic solution. It was.

DESCRIPTION OF SYMBOLS 1 Base material layer 2 Adhesion layer 3 Metal foil layer 4 Sealant layer 5 Acid reaction resin layer

Claims (7)

It consists of a laminate having at least a base material layer, an adhesive layer, a metal foil layer, and a sealant layer in this order,
A battery packaging material comprising an acid-reactive resin layer containing an acid-curable resin between the adhesive layer and the metal foil layer and / or between the metal foil layer and the sealant layer. .   The battery packaging material according to claim 1, wherein the acid-reactive resin layer is provided at least between the metal foil layer and the sealant layer.   The battery packaging material according to claim 1 or 2, wherein the acid curable resin is an acid curable furan resin and / or an acid curable phenol resin.   The battery packaging material according to any one of claims 1 to 3, wherein the acid-reactive resin layer has a thickness of 0.01 µm or more.   The battery packaging material according to any one of claims 1 to 4, wherein the metal foil layer is an aluminum foil. A method for producing a battery packaging material including the following steps:
A first step of forming a laminate in which an acid-reactive resin layer containing an acid-curable resin is laminated on at least one surface of the metal foil layer;
A second step of forming a laminate in which a base material layer is laminated on the laminate obtained in the first step via an adhesive layer, and a base material layer of the laminate obtained in the second step A third step of laminating a sealant layer on the opposite surface.   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 claim 1.