JP6707315B2 - Battery packaging material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a battery packaging material that has distinguishability from the outside, is excellent in moldability and insulation properties, and has suppressed appearance defects and seal defects.

Conventionally, various types of batteries have been developed, but in all batteries, 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, along with higher performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, and the like, batteries are required to have various shapes, and to be thin and lightweight. However, the metal battery packaging materials that have been widely used in the past have the drawbacks that it is difficult to follow the diversification of shapes and there is a limit to weight reduction.

Therefore, in recent years, a film-like laminate in which a base material/adhesive layer/metal layer/sealant layer is sequentially laminated is used as a battery packaging material that can be easily processed into various shapes and can be made thin and lightweight. Proposed. In the process of manufacturing a battery using such a packaging material for a battery, a label with product information of the battery is attached to the surface of the packaging material for the battery, or the surface of the packaging material for the battery is used instead of the label. Product information etc. may be printed directly by inkjet.

However, if the same identification mark as the official manufacturer is attached to the counterfeit battery different from the original manufacturer by the above label or printing, it will be difficult to distinguish between the genuine product and the counterfeit product. There is a problem.

As a method for solving such a problem, for example, Patent Document 1 discloses a multilayer film having a structure in which a base material layer, an adhesive layer, a metal foil layer, and a thermoadhesive resin layer are laminated in this order. There is disclosed a packaging material for an electrochemical cell in which the material layer or the adhesive layer contains a pigment as an identification mark. According to the method described in Patent Document 1, a packaging material for an electrochemical cell having an identification mark that can be recognized from the outside and that is difficult to forge can be obtained.

JP, 2011-54563, A

As described above, it is possible to distinguish between a genuine battery and a counterfeit product by manufacturing a battery using the packaging material for an electrochemical cell that is distinguishable from the outside as disclosed in Patent Document 1. Becomes However, as a result of intensive studies by the present inventor, as in Patent Document 1, when a pigment that is contained in a resin that forms a base material layer is used as an identification mark, the pigment is a solid particle, and therefore, for a battery. It became clear that the pigment may be separated from the resin during the molding of the packaging material, and pinholes may be generated in the separated part. When a pigment is added to the adhesive layer interposed between the base material layer and the metal foil layer, the adhesive layer contains solid particles. For this reason, the adhesiveness of the adhesive layer may be reduced, and delamination may occur. Further, in such a case, it has been clarified that, when the battery packaging material is deeply molded, it causes floating and deterioration of color tone in a greatly stretched portion such as a molding corner.

In particular, in recent years, packaging materials for batteries have been required to be even thinner, so that pinholes are more likely to occur during molding. When pinholes are generated in the battery packaging material, there is a problem that the insulating property of the battery packaging material is reduced. In addition, the pigment contained in the resin may fall off during the manufacturing process of the battery packaging material or battery, which tends to cause poor appearance of the battery packaging material or defective sealing due to the adhesion of the pigment to the sealing portion. There is also the problem of becoming.

Under such circumstances, the present invention has a main object to provide a packaging material for a battery that has distinguishability from the outside, is excellent in moldability and insulating properties, and has suppressed appearance defects and seal defects. And

The present inventor has diligently studied to solve the above problems. As a result, at least a base material layer, an adhesive layer, a metal layer, and a sealant layer consisting of a laminate that is sequentially laminated, at least one of the base material layer and the adhesive layer is a battery packaging material containing a dye, It has been found that it has distinguishability from the outside, has excellent moldability and insulating properties, and can suppress appearance defects and seal defects. The present invention has been completed by further studies based on such findings.

That is, the present invention provides a battery packaging material and a battery having the following aspects.
Item 1. At least a base material layer, an adhesive layer, a metal layer, and a sealant layer consisting of a laminated body sequentially laminated,
A packaging material for a battery, wherein at least one of the base material layer and the adhesive layer contains a dye.
Item 2. Item 2. The battery packaging material according to Item 1, wherein the color of the dye constitutes an identification mark.
Item 3. Item 3. The battery packaging material according to Item 1 or 2, wherein the base material layer contains the dye.
Item 4. Item 4. The battery packaging material according to any one of Items 1 to 3, wherein the concentration of the dye in the base layer is 1 to 50% by mass.
Item 5. The dye is at least one selected from the group consisting of nitro dyes, azo dyes, stilbene dyes, calponium dyes, quinoline dyes, methine dyes, thiazole dyes, quinimine dyes, anthraquinone dyes, indigoid dyes, and phthalocyanine dyes. 5. The battery packaging material according to any one of Items 1 to 4.
Item 6. Item 6. The battery packaging material according to any one of Items 1 to 5, which is a packaging material for a secondary battery.
Item 7. A battery in which a battery element including at least a positive electrode, a negative electrode, and an electrolyte is housed in the battery packaging material according to any one of Items 1 to 6.

Advantageous Effects of Invention According to the present invention, it is possible to provide a battery packaging material that has distinguishability from the outside, is excellent in moldability and insulating properties, and can suppress poor appearance and poor sealing. Furthermore, according to the present invention, by using the packaging material for a battery in a battery, it is possible to provide a battery that has excellent insulation properties, is suppressed in appearance defects and seal defects, and can be distinguished from a counterfeit product from the outside. be able to.

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 is composed of a laminate in which at least a base material layer, an adhesive layer, a metal layer, and a sealant layer are sequentially laminated, and at least one of the base material layer and the adhesive layer contains a dye. And Hereinafter, the battery packaging material of the present invention will be described in detail.

1. Laminated Structure of Battery Packaging Material As shown in FIG. 1, the battery packaging material comprises a laminate in which at least a base material layer 1, an adhesive layer 2, a metal layer 3, and a sealant layer 4 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 4 is the innermost layer. That is, at the time of assembling the battery, the sealant layers 4 located at the periphery of the battery element are heat-sealed to seal the battery element, thereby sealing the battery element.

In the battery packaging material of the present invention, as shown in FIG. 2, an adhesive layer 5 is optionally provided between the metal layer 3 and the sealant layer 4 for the purpose of enhancing the adhesiveness between them. May be.

2. Composition of each layer forming the 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. In the present invention, at least one of the base material layer 1 and the adhesive layer 2 described later contains a dye. The dye is not particularly limited as long as it can be dissolved/dispersed in the material constituting the base material layer 1 or the adhesive layer 2 to be described later, but is not limited to nitro dye, azo dye, stilbene dye, carponium dye, quinoline dye, methine. Examples thereof include dyes, thiazole dyes, quinimine dyes, anthraquinone dyes, indigoid dyes, and phthalocyanine dyes, with preference given to azo dyes, carponium dyes, and anthraquinone dyes. Among these, azo dyes and anthraquinone dyes are more preferable from the viewpoint of further improving the external distinguishability, moldability, and insulating property of the battery packaging material of the present invention. The dyes may be used alone or in combination of two or more.

When the base material layer 1 contains a dye, the concentration of the dye in the base material layer 1 is not particularly limited as long as it can provide the battery packaging material with distinguishability from the outside, but is preferably about 1 to 50% by mass, more preferably Is about 2 to 40% by mass, more preferably about 3 to 30% by mass. As will be described later, when the base material layer 1 is a multilayer, the concentration is the concentration of the layer containing the dye.

In the present invention, at least one of the base material layer 1 and the adhesive layer 2 to be described later contains a dye, and therefore has distinguishability from the outside. Specifically, since these layers are colored by the dye contained in at least one of the base material layer 1 and the adhesive layer 2 which will be described later, the battery packaging material can be identified from the outside by this color. That is, in the present invention, the color of the dye constitutes the identification mark. For this reason, even when a label serving as a forgery identification mark is attached to or printed on the battery packaging material, the color difference that can be recognized from the appearance of the battery packaging material causes a difference in product (battery packaging material). It is possible to easily determine the authenticity of a battery or a battery using the same.

Further, as described above, for example, when coloring with a pigment is used as an identification mark, when the pigment is added to the base material layer, the pigment is a solid particle, and therefore the shape change (elongation) of the base material layer during the molding of the battery packaging material. In some cases, pinholes are partially generated to reduce the insulation property. Also, when a pigment is added to the adhesive layer, the solid particles may reduce the adhesiveness and cause delamination. In addition, the pigment may fall off during the manufacturing process of the battery packaging material, the manufacturing process of the battery, or the storage, and the dropped pigment may adhere to the surface of the battery packaging material to cause a defective appearance, or the seal part Due to the adhesion of the pigment, defective sealing easily occurs. On the other hand, in the battery packaging material of the present invention, since the above dye is used for coloring the base material layer 1 and the adhesive layer 2, these problems caused by solid particles are unlikely to occur. Therefore, the battery packaging material of the present invention has excellent distinguishability from the outside, excellent moldability and insulating properties, and can suppress defective appearance and defective sealing.

The material forming the base material layer 1 is not particularly limited as long as it has insulating properties and dissolves/disperses the above dye. As a material for forming the base material layer 1, for example, a resin (resin such as polyester resin, polyamide resin, epoxy resin, acrylic resin, fluororesin, polyurethane resin, silicon resin, phenol resin, or a mixture or copolymer thereof) is used. Film). Among these, polyester resin and polyamide resin are preferable, and biaxially stretched polyester resin and biaxially stretched polyamide resin are more preferable. Specific examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, copolyester, and polycarbonate. Specific examples of the polyamide resin include nylon 6, nylon 6,6, a copolymer of nylon 6 and nylon 6,6, nylon 6,10, polymethaxylylene adipamide (MXD6), and the like. Be done.

The base material layer 1 may be a single layer or a multilayer. When the base material layer 1 is a multi-layer, each layer can be laminated with, for example, an adhesive or an adhesive resin, and as a laminating method, a dry laminating method or a co-extrusion method can be adopted. The type and amount of the adhesive used are the same as in the case of the adhesive layer 2 or the adhesive layer 5 described later.

The thickness of the base material layer 1 is not particularly limited, but is, for example, about 5 to 30 μm, preferably about 7 to 25 μm.

[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 metal layer 3 in order to firmly bond them. The adhesive layer 2 is formed of an adhesive that can bond the base material layer 1 and the metal layer 3 together. Furthermore, in the present invention, as described above, at least one of the base material layer 1 and the adhesive layer 2 contains a dye. When the adhesive layer 2 contains a dye, the concentration of the dye in the adhesive layer 2 is not particularly limited as long as it can provide the battery packaging material with distinguishability from the outside, but is preferably about 1 to 50% by mass, more preferably 2%. ˜40% by mass, more preferably about 3 to 30% by mass. As will be described later, when the adhesive layer 2 is a multilayer, the concentration is the concentration of the layer containing the dye.

The adhesive used for forming the adhesive layer 2 may be a two-component curable adhesive or a one-component curable adhesive. Further, the adhesion 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 hot pressing type and the like.

Specific examples of the resin component of the adhesive that can be used for forming the adhesive layer 2 include polyester-based resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, and copolyester. Resin: Polyether-based adhesive; Polyurethane-based adhesive; Epoxy-based resin; Phenolic resin-based resin; Nylon 6, Nylon 66, Nylon 12, polyamide-based resin such as copolyamide; Polyolefin, acid-modified polyolefin, metal-modified polyolefin, etc. Polyolefin resin; polyvinyl acetate resin; cellulose adhesive; (meth)acrylic resin; polyimide resin; urea resin, amino resin such as melamine resin; chloroprene rubber, nitrile rubber, rubber such as styrene-butadiene rubber A silicone resin; a fluoroethylene propylene copolymer and the like. These adhesive components may be used alone or in combination of two or more. The combination mode of two or more adhesive components is not particularly limited, but 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 include mixed resins of polyester and acid-modified polyolefin, mixed resins of polyester and metal-modified polyolefin, and the like. Among these, extensibility, durability under high humidity conditions, an effect of suppressing change, and an effect of suppressing heat deterioration at the time of heat sealing are excellent, and a decrease in lamination strength between the base material layer 1 and the metal layer 3 is suppressed. From the viewpoint of effectively suppressing the occurrence of delamination, a polyurethane-based two-component curable adhesive; polyamide, polyester, or a blend resin of these and a modified polyolefin is preferable.

Further, 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 of the base layer 1 and the metal layer 3, the adhesive component disposed on the base layer 1 side is used as the base layer 1. It is preferable to select a resin having excellent adhesiveness to the metal layer 3 and an adhesive component having excellent adhesiveness to the metal layer 3 as the adhesive component disposed on the metal layer 3 side. When the adhesive layer 2 is multilayered with different adhesive components, specifically, the adhesive component disposed on the metal layer 3 side is preferably an acid-modified polyolefin, a metal-modified polyolefin, a polyester and an acid-modified polyolefin. Examples of the mixed resin, a resin containing a copolyester, and the like.

The thickness of the adhesive layer 2 is, for example, 2 to 50 μm, preferably 3 to 25 μm.

[Metal layer 3]
In the battery packaging material, the metal layer 3 is a layer that not only improves the strength of the battery packaging material but also functions as a barrier layer for preventing water vapor, oxygen, light, and the like from entering the inside of the battery. Specific examples of the metal forming the metal layer 3 include aluminum, stainless steel, titanium, and the like, and aluminum is preferable. The metal layer 3 can be formed by a metal foil, metal vapor deposition, or the like, preferably a metal foil, and more preferably an aluminum foil. From the viewpoint of preventing wrinkles and pinholes from being generated in the metal layer 3 during the production of the battery packaging material, for example, a soft aluminum foil such as annealed aluminum (JIS A8021P-O, JIS A8079P-O) is used. It is more preferable to form.

The thickness of the metal layer 3 is not particularly limited, but may be, for example, about 10 μm to 200 μm, preferably about 20 μm to 100 μm.

In addition, it is preferable that at least one surface, preferably both surfaces, of the metal layer 3 is subjected to chemical conversion treatment in order to stabilize adhesion, prevent dissolution and corrosion. Here, the chemical conversion treatment means a treatment for forming an acid resistant film on the surface of the metal layer. Examples of the chemical conversion treatment include chromate chromate using a chromate compound such as chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium diphosphate, acetyl acetate chromate, chromium chloride, and potassium chromium sulfate. Treatment; Phosphoric acid chromate treatment using a phosphoric acid compound such as sodium phosphate, potassium phosphate, ammonium phosphate, and polyphosphoric acid; Aminated phenol having repeating units represented by the following general formulas (1) to (4) Examples include chromate treatment using a polymer.

In 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, Examples thereof include linear or branched alkyl groups having 1 to 4 carbon atoms such as tert-butyl group. 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 and a 3-hydroxypropyl group. A straight or branched chain having 1 to 4 carbon atoms 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 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, and more preferably about 1,000 to 20,000. preferable.

As a chemical conversion treatment method for imparting corrosion resistance to the metal layer 3, phosphoric acid is coated with a dispersion of metal oxides such as aluminum oxide, titanium oxide, cerium oxide, and tin oxide and fine particles of barium sulfate, A method of forming a corrosion resistant treatment layer on the surface of the metal layer 3 by performing a baking treatment at 150° C. or higher can be mentioned. Further, a resin layer obtained by crosslinking a cationic polymer with a crosslinking agent may be further formed on the anticorrosion treated 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-grafted acrylic resin obtained by graft-polymerizing a primary amine on an acrylic main skeleton, and a polyallylamine. Alternatively, derivatives thereof, aminophenol and the like can be mentioned. As these cationic polymers, only one kind may be used, or two or more kinds may be used in combination. Examples of the cross-linking agent include compounds 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 cross-linking agents, only one kind may be used, or two or more kinds may be used in combination.

As the chemical conversion treatment, only one type of chemical conversion treatment may be performed, or two or more types of chemical conversion treatment may be performed in combination. Furthermore, these chemical conversion treatments may be performed using one type of compound alone, or may be performed using two or more types of compounds in combination. Among the chemical conversion treatments, chromate chromate treatment and chromate treatment in which a chromate compound, a phosphoric acid compound, and an aminated phenol polymer are combined are preferable.

The amount of the acid resistant film formed on the surface of the metal layer 3 in the chemical conversion treatment is not particularly limited, but for example, when the above chromate treatment is performed, the chromic acid compound is added per 1 m ² of the surface of the metal layer 3. Chromium conversion is about 0.5 mg to about 50 mg, preferably about 1.0 mg to about 40 mg, phosphorus compound is about 0.5 mg to about 50 mg, preferably about 1.0 mg to about 40 mg, and aminated phenol weight. It is desirable that the combined amount be contained in a ratio of about 1 mg to about 200 mg, preferably about 5.0 mg to 150 mg.

The chemical conversion treatment is carried out by applying a solution containing a compound used for forming an acid resistant film to the surface of the metal layer by a bar coating method, a roll coating method, a gravure coating method, a dipping method or the like, and then the temperature of the metal layer is 70 It is carried out by heating so that the temperature becomes from about ℃ to 200 ℃. In addition, before subjecting the metal layer to chemical conversion treatment, the metal layer may be previously subjected to 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 treatment in this manner, it becomes possible to more efficiently perform the chemical conversion treatment on the surface of the metal layer.

[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 during the assembly of the battery.

The resin component used in the sealant layer 4 is not particularly limited as long as it can be heat-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, propylene-ethylene block copolymer), polypropylene. Random copolymers (for example, random copolymers of propylene and ethylene); ethylene-butene-propylene terpolymers; 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, isoprene, and the like. Is mentioned. Examples of the cyclic monomer which 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 alkenes are preferable, and norbornene is more preferable.

The carboxylic acid-modified polyolefin is a polymer modified by subjecting the polyolefin to block polymerization or graft polymerization with a carboxylic acid. Examples of the carboxylic acid used for modification include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride.

The carboxylic acid-modified cyclic polyolefin is obtained by copolymerizing a part of the monomers constituting the cyclic polyolefin by substituting α,β-unsaturated carboxylic acid or its anhydride, or by adding α,β to the cyclic polyolefin. -A polymer obtained by block-polymerizing or graft-polymerizing an unsaturated carboxylic acid or an anhydride thereof. The cyclic polyolefin modified with carboxylic acid is the same as described above. The carboxylic acid used for modification is the same as that used for modifying the acid-modified cycloolefin copolymer.

Among these resin components, carboxylic acid-modified polyolefin is preferable; and carboxylic acid-modified polypropylene is more preferable.

The sealant layer 4 may be formed of one type of resin component alone, or may be formed of a blend polymer in which two or more types of resin components are combined. Further, the sealant layer 4 may be formed of only one layer, but may be formed of two or more layers with the same or different resin components.

Further, the thickness of the sealant layer 4 can be appropriately selected, but is 10 to 100 μm, preferably 15 to 50 μm.

[Adhesive layer 5]
In the battery packaging material, an adhesive layer 5 may be further provided between the metal layer 3 and the sealant layer 4 for the purpose of firmly adhering the metal layer 3 and the sealant layer 4.

The adhesive layer 5 is formed of an adhesive component capable of adhering the metal layer 3 and the sealant layer 4 described later. The adhesive used for forming the adhesive layer 5 may be a two-component curable adhesive or a one-component curable adhesive. Further, the adhesive mechanism of the adhesive component used for forming the adhesive layer 5 is not particularly limited, and examples thereof include a chemical reaction type, a solvent volatilization type, a heat melting type, and a heat pressure type.

Specific examples of the adhesive component that can be used to form the adhesive layer 5 include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate and copolyester; polyether. -Based adhesives; polyurethane-based adhesives; epoxy-based resins; phenolic-based resins; polyamide-based resins such as nylon 6, nylon 66, nylon 12 and copolyamides; polyolefins such as polyolefins, carboxylic acid-modified polyolefins, metal-modified polyolefins, etc. Resins, polyvinyl acetate resins; cellulosic adhesives; (meth)acrylic resins; polyimide resins; amino resins such as urea resins and melamine resins; rubbers such as chloroprene rubber, nitrile rubber, styrene-butadiene rubber; silicone resins Resin etc. are mentioned. These adhesive components may be used alone or in combination of two or more.

The thickness of the adhesive layer 5 is not particularly limited, but is preferably about 1 μm to 40 μm, and more preferably about 2 μm to 30 μm, for example.

3. Method for producing battery packaging material The method for producing the battery packaging material of the present invention is not particularly limited, as long as a laminate obtained by laminating each layer having a predetermined composition is obtained, but for example, the following method is exemplified. ..

First, a laminated body (hereinafter, also referred to as “laminated body A”) in which the base material layer 1, the adhesive layer 2, and the metal layer 3 are laminated in order is formed. Specifically, the laminate A is formed by using an extrusion method, a gravure coat method, an adhesive used for forming the adhesive layer 2 on the base material layer 1 or on the metal layer 3 whose surface has been subjected to chemical conversion treatment, if necessary. After coating and drying by a coating method such as a coating method or a roll coating method, the metal layer 3 or the base material layer 1 is laminated and the adhesive layer 2 is cured by a dry lamination method.

Then, the sealant layer 4 is laminated on the metal layer 3 of the laminate A. When the sealant layer 4 is directly laminated on the metal layer 3, the resin component forming the sealant layer 4 may be applied on the metal layer 3 of the laminate A by a method such as a gravure coating method or a roll coating method. .. When the adhesive layer 5 is provided between the metal layer 3 and the sealant layer 4, for example, (1) the adhesive layer 5 and the sealant layer 4 are laminated on the metal layer 3 of the laminate A by coextrusion. Method (coextrusion lamination method), (2) separately forming a laminate in which the adhesive layer 5 and the sealant layer 4 are laminated, and laminating this on the metal layer 3 of the laminate A by the thermal lamination method, 3) The adhesive for forming the adhesive layer 5 is laminated on the metal layer 3 of the laminate A by an extrusion method, a solution coating method, a drying method at a high temperature, or a baking method, and the sheet shape is preliminarily formed on the adhesive layer 5. A method of laminating the sealant layer 4 formed into a film by the thermal lamination method, (4) a melted adhesive layer 5 between the metal layer 3 of the laminate A and the sealant layer 4 formed into a sheet in advance. A method (sand lamination method) of bonding the laminate A and the sealant layer 4 via the adhesive layer 5 while pouring them in may be mentioned.

As described above, a laminate including the base material layer 1/adhesive layer 2/metal layer 3 whose surface has been subjected to chemical conversion treatment/adhesive layer 5/sealant layer 4 provided as needed is formed. However, in order to strengthen the adhesiveness of the adhesive layer 2 and the adhesive layer 5 that is provided as necessary, you may further subject it to heat treatment such as hot roll contact type, hot air type, near or far infrared type. The conditions for such heat treatment include, for example, 150 to 250° C. and 1 to 5 minutes.

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

4. Use of Battery Packaging Material The battery packaging material of the present invention is used as a packaging material for hermetically containing battery elements such as a positive electrode, a negative electrode and an electrolyte.

Specifically, a battery element having at least a positive electrode, a negative electrode, and an electrolyte, in the battery packaging material of the present invention, in a state where the metal terminals connected to each of the positive electrode and the negative electrode are projected outward, By covering the periphery of the element so that a flange portion (a region where the sealant layers contact each other) can be formed and sealing the sealant layers of the flange portion by heat sealing, a battery using a battery packaging material can be obtained. Provided. When a battery element is accommodated by using the battery packaging material of the present invention, the sealant portion of the battery packaging material of the present invention is used so that the sealant portion is on the inner side (the surface in contact with the battery element).

The battery packaging material of the present invention may be used in either a primary battery or a secondary battery, but is preferably a secondary battery. The type of the secondary battery to which the battery packaging material of the present invention is applied is not particularly limited, and examples thereof include a lithium ion battery, a lithium ion polymer battery, a lead storage battery, a nickel/hydrogen storage battery, and a nickel/cadmium storage battery. , Nickel/iron storage battery, nickel/zinc storage battery, silver oxide/zinc storage battery, metal-air battery, polyvalent cation battery, capacitor, capacitor and the like. Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries are mentioned as suitable targets for application of the battery packaging material of the present invention. Since the battery of the present invention uses the above-mentioned battery packaging material of the present invention, it has excellent insulation properties, suppressed appearance defects and seal defects, and can be discriminated from a counterfeit product from the outside.

The present invention will be described in detail below with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples.

A chemical conversion treatment is applied to both sides of an aluminum foil (40 μm thick), and a polyethylene terephthalate (PET) film (12 μm thick) is applied to one of the chemical conversion treated surfaces so that the adhesive layer has a thickness of about 4 μm. By a dry laminating method, melt-extruding acid-modified polypropylene (thickness 23 μm) on the other chemical conversion treated surface and laminating a sealant film made of polypropylene film (thickness 23 μm), PET film/polyester A battery packaging material composed of a system adhesive/double-sided chemical conversion-treated aluminum/acid-modified polypropylene/polypropylene film was obtained. The PET film used in Example 1 contains 20% by mass of p-phenylazophenol as a coloring dye. Further, the PET film used in Comparative Example 1 does not use a coloring dye, but contains 10% by mass of titanium oxide as a coloring pigment. Furthermore, in Comparative Example 2, the PET film contained no colorant, and the adhesive contained 10 mass% of titanium oxide as a color pigment.

The aluminum foil chemical conversion treatment was performed by roll coating using an aqueous solution containing a phenol resin, a chromium fluoride compound, and phosphoric acid as a treatment liquid, and baking under conditions where the coating temperature was 180°C or higher. It was The amount of chromium applied was 10 mg/m ² (dry weight).

[Moldability evaluation]
The battery packaging materials produced in Example 1 and Comparative Examples 1 and 2 were cut into 120×80 mm strips, and a 55×32 mm rectangular male die had a clearance of 0.3 mm. Using a straight mold (male corner R: 2 mm, ridgeline R: 1 mm) consisting of a female mold, place strips on the female mold so that the heat-adhesive resin layer is located on the male mold side. The strips are pressed with a pressing pressure (surface pressure) of 0.16 MPa, and each depth is molded in 0.1 mm increments between 3.0 and 4.0 mm to form a rectangular concave shape of 55×32 mm. A molded container (tray) having flanges at four peripheral edges of a concave mold was produced. Table 1 shows the presence or absence of pinholes in the molded container. In Table 1, no occurrence of pinholes is indicated by ◯ and occurrence of pinholes is indicated by x.

[Evaluation of dielectric breakdown voltage]
Table 1 shows the results of evaluating the dielectric breakdown voltage using a dielectric container testing device (YST-243-100RHO manufactured by Yamayo Tester Co., Ltd.) separately prepared for the molded container prepared by the above moldability evaluation.

As is clear from the results shown in Table 1, in the battery packaging material of Comparative Example 1 using the color pigment in the PET film, the molding depth was 3.3 mm or more, and the comparative example 2 using the color pigment in the adhesive was used. In the battery packaging material, the molding depth was 3.5 mm or more, and pinholes were generated in each case, whereas in the battery packaging material of Example 1 using the colored dye, the molding depth was up to 3.8 mm. It was found that pinholes did not occur and the moldability was better than in Comparative Examples 1 and 2.

Further, in the battery packaging material of Comparative Example 1, a decrease in dielectric breakdown voltage was observed at a molding depth of 3.2 mm and in the battery packaging material of Comparative Example 2 at 3.3 mm, whereas in Example 1, It was found that the insulation breakdown voltage did not decrease until the molding depth was 3.7 mm, and that the insulation properties were superior to those of Comparative Examples 1 and 2. Furthermore, in the battery packaging material of Comparative Example 2, it was found that color unevenness occurred at the molding corners and the color tone changed.

From the above results, when the coloring dye is used for the identification mark, its color can be recognized from the outside, and it functions as an identification mark that is difficult to forge, and compared to the case where the coloring pigment is used for the identification mark. It can be seen that the moldability and insulation are excellent.

1 Base Material Layer 2 Adhesive Layer 3 Metal Layer 4 Sealant Layer 5 Adhesive Layer

Claims (6)

At least a base material layer, an adhesive layer, a metal layer, and a sealant layer consisting of a laminated body sequentially laminated,
The resin film constituting the base material layer can be dissolved and dispersed in the resin film, and contains a dye that is not solid particles,
The above-mentioned dye is at least one selected from the group consisting of nitro dye, stilbene dye, carponium dye, quinoline dye, methine dye, thiazole dye, quinimine dye, anthraquinone dye, indigoid dye, and phthalocyanine dye. material. The battery packaging material according to claim 1, wherein the color of the dye constitutes an identification mark. The adhesive layer, which can be dissolved and dispersed in the material constituting the adhesive layer , contains a dye that is not solid particles,
The dye is at least one selected from the group consisting of a nitro dye, a stilbene dye, a carponium dye, a quinoline dye, a methine dye, a thiazole dye, a quinimine dye, an anthraquinone dye, an indigoid dye, and a phthalocyanine dye. Or the battery packaging material according to 2. The packaging material for a battery according to claim 1, wherein the concentration of the dye in the base layer is 1 to 50 mass %. The packaging material for a battery according to any one of claims 1 to 4, which is a packaging material for a secondary battery. A battery, wherein a battery element including at least a positive electrode, a negative electrode, and an electrolyte is housed in the battery packaging material according to any one of claims 1 to 5.