JP6476679B2 - Battery packaging materials - Google Patents

Description

  The present invention relates to a battery packaging material excellent in moldability and electrolyte solution resistance.

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

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

  Therefore, in recent years, a film-like laminate in which a base material / metal layer / sealant layer are sequentially laminated has been proposed as a packaging material for batteries that can be easily processed into various shapes and can be made thin and light. Yes. However, such a film-shaped packaging material has a drawback that it is thinner than a metal packaging material and easily causes pinholes and cracks during molding. When pinholes or cracks occur in battery packaging materials, the electrolyte can penetrate into the metal layer to form metal deposits, which can result in short circuits. It is indispensable for the battery packaging material to have a characteristic that does not easily cause pinholes during molding, that is, excellent moldability.

  From the viewpoint of improving the moldability of battery packaging materials, nylon films are widely used as the base material (see, for example, Patent Document 1). However, when manufacturing a battery using a battery packaging material in which a nylon film is used as the base material, there is a problem that the base material surface may be whitened or melted if the electrolyte solution adheres to the base material surface. .

  On the other hand, from the viewpoint of increasing the electrolytic solution resistance of the substrate surface, it is conceivable to use a polyester resin film (for example, a polyethylene terephthalate (PET) film) excellent in electrolytic solution resistance as the substrate. However, since the polyester resin film has low moldability, it has a problem that pinholes are likely to occur during molding.

JP 2008-288117 A

  The main object of the present invention is, at least, a battery packaging material comprising a film-like laminate in which a base material layer, an adhesive layer, a metal layer, and a sealant layer are sequentially laminated. Furthermore, it is an object of the present invention to provide a technique for providing an excellent moldability that hardly causes cracks and pinholes during molding.

  The present inventors have intensively studied to solve the above-described problems. As a result, in a battery packaging material comprising a laminate in which at least a base material layer, an adhesive layer, a metal layer, and a sealant layer are sequentially laminated, the base material layer includes at least a polyester resin layer and a polyamide resin layer. It is formed of a stretched film, and the tensile break elongation in the MD direction and the TD direction of the base material layer is set in the range of 85 to 130%, and further, the tensile force in the MD direction with respect to the tensile break elongation in the TD direction of the base material layer. By setting the ratio of elongation at break (MD / TD) in the range of 1.0 to 1.4, it is possible to achieve both excellent electrolytic solution resistance and excellent formability in battery packaging materials. I found. The present invention has been completed by further studies based on these findings.

That is, this invention provides the battery packaging material and battery of the aspect hung up below.
Item 1. It consists of a laminate in which at least a base material layer, an adhesive layer, a metal layer, and a sealant layer are sequentially laminated,
The base material layer is formed of a biaxially stretched film including at least a polyester resin layer and a polyamide resin layer,
The tensile break elongation in MD direction and TD direction of the base material layer is in the range of 85 to 130%,
The battery packaging material wherein the ratio of the tensile breaking elongation in the MD direction to the tensile breaking elongation in the TD direction of the base material layer (MD / TD) is in the range of 1.0 to 1.4.
Item 2. Item 2. The battery packaging material according to Item 1, wherein the base material layer is formed of a biaxially stretched film obtained by coextruding at least a polyester resin and a polyamide resin.
Item 3. Item 3. The battery packaging material according to Item 1 or 2, wherein the base material layer is formed of a biaxially stretched film in which a polyester resin layer, an adhesive resin layer, and a polyamide resin layer are laminated in this order.
Item 4. Item 4. The battery packaging material according to any one of Items 1 to 3, wherein in the base material layer, the polyester resin layer is located in an outermost layer opposite to the sealant layer.
Item 5. Item 5. The battery packaging material according to any one of Items 1 to 4, wherein the tensile strength at break in the MD direction and the TD direction of the base material layer is 250 MPa or more.
Item 6. Item 6. The battery according to any one of Items 1 to 5, wherein a ratio of the tensile breaking strength in the MD direction to the tensile breaking strength in the TD direction of the base material layer (MD / TD) is in the range of 0.8 to 1.1. Packaging materials.
Item 7. The metal layer has a 0.2% proof stress when a tensile test in a direction parallel to the MD direction and a 0.2% proof stress when a tensile test in a direction parallel to the TD direction are performed. Item 7. The battery packaging material according to any one of Items 1 to 6, wherein both are aluminum foils in the range of 55 to 140 N / mm ² .
Item 8. Item 8. The battery packaging material according to any one of Items 1 to 7, wherein a chemical conversion treatment is applied to at least one surface of the metal layer.
Item 9. Item 9. The battery packaging material according to any one of Items 1 to 8, which is a packaging material for a secondary battery.
Item 10. Item 10. A battery in which a battery element including at least a positive electrode, a negative electrode, and an electrolyte is accommodated in the battery packaging material according to any one of Items 1 to 9.

  According to the battery packaging material of the present invention, the base material layer is formed of a biaxially stretched film including at least a polyester resin layer and a polyamide resin layer, and tensile elongation at break in the MD direction and the TD direction of the base material layer. Are both in the range of 85 to 130%, and the ratio of the tensile breaking elongation in the MD direction to the tensile breaking elongation in the TD direction of the base material layer (MD / TD) is in the range of 1.0 to 1.4. As a result, since excellent moldability is provided, it is possible to suppress the occurrence of pinholes, cracks and the like during the molding of the battery packaging material. Furthermore, since it has excellent electrolytic solution resistance due to the configuration, dissolution of the base material layer when the electrolytic solution adheres to the base material layer surface can be effectively suppressed. .

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 in which at least a base material layer, an adhesive layer, a metal layer, and a sealant layer are sequentially laminated. The base material layer includes at least a polyester resin layer and a polyamide resin layer. It is formed of an axially stretched film, and the tensile break elongation in the MD direction and the TD direction of the base material layer is in the range of 85 to 130%, and in the MD direction with respect to the tensile break elongation in the TD direction of the base material layer. The ratio of tensile elongation at break (MD / TD) is in the range of 1.0 to 1.4. Hereinafter, the battery packaging material of the present invention will be described in detail.

1. 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, when the battery is assembled, the sealant layers 4 positioned at the periphery of the battery element are thermally welded to seal the battery element, thereby sealing the battery element.

  The base material layer 1 includes at least a polyester resin layer 1a and a polyamide resin layer 1b. An adhesive resin layer 1c may be laminated between the polyester resin layer 1a and the polyamide resin layer 1b as necessary for the purpose of enhancing the adhesion. From the viewpoint of improving the electrolytic solution resistance of the battery packaging material, in the base material layer 1, the polyester resin layer 1 a is preferably located in the outermost layer opposite to the sealant layer 4. Further, as shown in FIG. 2, the battery packaging material of the present invention is provided with an adhesive layer 5 between the metal layer 3 and the sealant layer 4 as necessary for the purpose of enhancing the adhesiveness thereof. May be. Although not shown, a coating layer may be provided on the surface of the base material layer 1 (surface opposite to the sealant layer 4).

2. Composition of each layer forming base material for battery [base material layer 1]
In the battery packaging material of the present invention, the base material layer 1 is an outermost layer and is an insulating layer. In the present invention, the base material layer 1 is formed of a biaxially stretched film including at least a polyester resin layer 1a and a polyamide resin layer 1b.

  Specific examples of the polyester resin that forms the polyester resin layer 1a include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, copolymerized polyester, and polycarbonate. Examples of the copolyester include ethylene terephthalate / ethylene isophthalate copolymer, butylene terephthalate / butylene isophthalate copolymer, and the like. The polyester resin that forms the polyester resin layer 1a may be a single type or a combination of two or more types.

  From the viewpoint of improving the electrolytic solution resistance of the battery packaging material, the polyester resin layer 1a is preferably located in the outermost layer on the side opposite to the sealant layer 4 of the base material layer 1. That is, the presence of the polyester resin layer 1a in the outermost layer of the battery packaging material effectively suppresses not only the dissolution when the electrolytic solution adheres but also the whitening of the surface of the battery packaging material. it can.

  From the viewpoint of achieving both excellent moldability of the battery packaging material and excellent electrolytic solution resistance, the thickness of the polyester resin layer 1a is preferably about 1 to 15 μm, and more preferably about 3 to 12 μm.

  As the polyamide resin forming the polyamide resin layer 1b, nylon 6, nylon 6,6, a copolymer of nylon 6 and nylon 6,6, nylon 6,10, polymetaxylylene adipamide (MXD6), and these Among these, at least two types of copolymers are exemplified, and among these, nylon 6 is preferable.

  From the viewpoint of achieving both excellent moldability of the battery packaging material and excellent electrolytic solution resistance, the thickness of the polyamide resin layer 1b is preferably about 10 to 25 μm, more preferably about 12 to 15 μm.

  As a ratio of the thickness of the polyamide resin layer 1b to the thickness of the polyester resin layer 1a (polyamide resin layer 1b / polyester resin layer 1a) from the viewpoint of achieving both excellent moldability of the battery packaging material and excellent electrolytic solution resistance. Is preferably 0.8 or more, more preferably in the range of 1.2 to 5.0.

  An adhesive resin layer 1c may be laminated between the polyester resin layer 1a and the polyamide resin layer 1b as necessary for the purpose of enhancing the adhesion. When the adhesive resin layer 1c is laminated, the base material layer 1 may be formed of a biaxially stretched film in which a polyester resin layer, an adhesive resin layer, and a polyamide resin layer are laminated in this order. preferable. The resin for forming the adhesive resin layer 1c is not particularly limited as long as it can enhance the adhesion between the polyester resin layer 1a and the polyamide resin layer 1b. For example, a modified polyester elastomer resin, an acid-modified resin is used. Examples thereof include polyolefin resins.

  The base material layer 1 may further include other layers in addition to the polyester resin layer 1a, the polyamide resin layer 1b, and the adhesive resin layer 1c provided as necessary. Examples of the resin forming the other layer include epoxy resins, acrylic resins, fluororesins, polyurethane resins, silicon resins, phenol resins, and mixtures and copolymers thereof.

  As described above, in the present invention, the base material layer 1 is formed of a biaxially stretched film including at least the polyester resin layer 1a and the polyamide resin layer 1b, and further, the base material layer 1 (the resin film constituting the base material layer 1). ) In the MD direction and in the TD direction are both set in the range of 85 to 130%, and the ratio of tensile break elongation (MD / TD) described later is set in the range of 1.0 to 1.4. As a result, a battery packaging material having both excellent electrolytic solution resistance and excellent moldability can be obtained.

  The base material layer 1 is formed of a biaxially stretched film including at least the polyester resin layer 1a and the polyamide resin layer 1b, and the tensile break elongation in the MD direction and the TD direction of the base material layer 1 satisfies the above relationship. While having excellent electrolytic solution resistance, the occurrence of pinholes, cracks, etc. during molding is suppressed and details of the mechanism by which excellent moldability is achieved are not necessarily clear, It can be thought of as follows. That is, the tensile break elongation in the MD direction and the TD direction of the base material layer 1 satisfies the above relationship, so that the stress change of the metal layer 3 at the time of forming the battery packaging material can be appropriately controlled. It is considered that the deformation (elongation) of the metal layer 3 can be gradually changed, and the rapid deformation (elongation) of the battery packaging material is suppressed. For this reason, at the time of shaping | molding of the packaging material for batteries, it is thought that the metal layer 3 can be made to follow a metal mold | die shape moderately, and generation | occurrence | production of a pinhole, a crack, etc. is suppressed. If the tensile elongation at break is too low, the deformation (elongation) of the metal layer 3 is hindered. As a result, pinholes, cracks, etc. are likely to be generated. (Elongation) cannot be controlled, and pinholes, cracks, etc. are likely to occur. In addition, since the base material layer 1 includes the polyester resin layer 1b, excellent electrolytic solution resistance is exhibited.

  From the viewpoint of further improving the moldability from the viewpoint of more effectively suppressing the occurrence of pinholes and cracks during molding while imparting excellent electrolytic solution resistance to the battery packaging material of the present invention. The tensile elongation at break in the MD direction and the TD direction of the layer 1 is preferably in the range of 90 to 120%. In addition, the tensile breaking elongation of the base material layer 1 is a value obtained by measurement by a method based on JIS K7127.

  In this invention, ratio (MD / TD) of the tensile breaking elongation in MD direction with respect to the tensile breaking elongation in TD direction of the base material layer 1 exists in the range of 1.0-1.4. The details of the mechanism by which excellent formability is achieved by satisfying the above-described relationship between the tensile elongation at break is not necessarily clear, but if in this range, the balance in the MD direction / TD direction Therefore, it is considered that more uniform deformation is achieved at the time of forming the battery packaging material, and the occurrence of pinholes, cracks and the like is suppressed. From the viewpoint of further improving the moldability from the viewpoint of more effectively suppressing the occurrence of pinholes and cracks during molding while imparting excellent electrolytic solution resistance to the battery packaging material of the present invention. The ratio of elongation at break (MD / TD) is preferably in the range of 1.0 to 1.3.

  In the present invention, the tensile strength at break in the MD direction and the TD direction of the base material layer 1 is preferably 250 MPa or more, more preferably 260 to 290 MPa. Moreover, as ratio (MD / TD) of the tensile breaking strength in MD direction with respect to the tensile breaking strength in the TD direction of a base material layer (MD / TD), Preferably it is the range of 0.8-1.1, More preferably, it is 0.9-1. A range of 0 is mentioned. By having these values for the tensile strength at break of the base material layer 1, pinholes and cracks during molding can be more effectively suppressed and moldability can be further improved while having excellent electrolytic solution resistance. Can be. In addition, the tensile breaking strength of the base material layer 1 is a value obtained by measurement by a method based on JIS K7127.

  From the viewpoint of further improving the moldability and the electrolyte solution resistance of the battery packaging material of the present invention, the base material layer 1 is particularly preferably a biaxially stretched film formed by coextruding at least a polyester resin and a polyamide resin. preferable. A biaxially stretched film obtained by co-extrusion of a polyester resin and a polyamide resin can be obtained, for example, by heat-melting polyester resin pellets and polyamide resin pellets and co-extruding them in two or more layers from a T-die. It is done. When the adhesive resin layer 1c is laminated between the polyester resin layer 1a and the polyamide resin layer 1b, the adhesive resin pellets may be heated and melted and coextruded together with the polyester resin and the polyamide resin. A biaxially stretched film constituting the base material layer 1 is obtained by applying a sequential biaxial stretching method by a tenter method to the composite film obtained by coextrusion. In addition, various physical properties of the base material layer 1 such as the above-mentioned tensile breaking elongation and tensile breaking strength are the extrusion width from the T-die when obtaining a biaxially stretched film, the draw ratio, the heat treatment temperature, the ratio of the thickness of each layer, etc. Can be controlled by preparing

  You may add additives, such as antioxidant, a slip agent, an antiblocking agent, and a water repellent, to each layer which forms the base material layer 1 as needed.

  The total thickness of the base material layer 1 is not particularly limited as long as the battery packaging material satisfies the above physical properties while exhibiting the function as the base material layer, but is, for example, about 10 to 50 μm, preferably about 15 to 25 μm. Is mentioned.

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

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

  Specific examples of adhesive components that can be used to form the adhesive layer 2 include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, and copolyester; Ether adhesive; Polyurethane adhesive; Epoxy resin; Phenol resin resin; Polyamide resin such as nylon 6, nylon 66, nylon 12, copolymer polyamide; Polyolefin such as polyolefin, carboxylic acid modified polyolefin, metal modified polyolefin Resin, polyvinyl acetate resin; cellulose adhesive; (meth) acrylic resin; polyimide resin; amino resin such as urea resin and melamine resin; chloroprene rubber, nitrile rubber, styrene - rubbers such as butadiene rubber, silicone-based resins. These adhesive components may be used individually by 1 type, and may be used in combination of 2 or more type. Among these adhesive components, a polyurethane adhesive is preferable.

  Although it will not restrict | limit especially if the thickness of the contact bonding layer 2 exhibits the function as a contact bonding layer, For example, about 1-10 micrometers, Preferably about 2-5 micrometers is mentioned.

[Metal layer 3]
In the battery packaging material, the metal layer 3 is a layer that functions as a barrier layer for preventing water vapor, oxygen, light, and the like from entering the battery, in addition to improving the strength of the battery packaging material. Specific examples of the metal constituting the metal layer 3 include aluminum, stainless steel, and titanium, and preferably aluminum. The metal layer 3 can be formed by metal foil, metal vapor deposition, or the like, preferably by metal foil, and more preferably by aluminum foil. From the viewpoint of preventing generation of wrinkles and pinholes in the metal layer 3 during the production of the battery packaging material, for example, by using a soft aluminum foil such as annealed aluminum (JIS A8021P-O, JIS A8079P-O). More preferably, it is formed.

The aluminum foil used as the metal layer 3 has a 0.2% proof stress when a parallel tensile test is performed with respect to the MD direction and a 0.2% when a parallel tensile test is performed with respect to the TD direction. and strength are both preferably in the range of 55~140N / mm ^2, more preferably in the range of 60~100N / mm ^2. The 0.2% proof stress is a value measured by a tensile test specified in JIS Z 2241.

  Although the thickness of the metal layer 3 will not be restrict | limited especially if the function as a metal layer is exhibited, For example, about 10 micrometers-50 micrometers, Preferably it can be set as about 20 micrometers-40 micrometers.

  The metal layer 3 is preferably subjected to chemical conversion treatment on at least one surface, preferably both surfaces, for the purpose of stabilizing adhesion, preventing dissolution and corrosion, and the like. Here, the chemical conversion treatment refers to a treatment for forming an acid-resistant film on the surface of the metal layer. As the chemical conversion treatment, for example, chromate chromate using chromic acid compounds such as chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium biphosphate, chromic acetyl acetate, chromium chloride, potassium sulfate chromium, etc. 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.

  In addition, as a chemical conversion treatment method for imparting corrosion resistance to the metal layer 3, a metal oxide such as aluminum oxide, titanium oxide, cerium oxide, tin oxide, or barium sulfate fine particles dispersed in phosphoric acid is coated. 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 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, and a silane coupling agent. As these crosslinking agents, only one type may be used, or two or more types 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 carried out using one kind of compound alone, or may be carried out using a combination of two or more kinds of compounds. Among the chemical conversion treatments, chromic acid chromate treatment, chromate treatment combining a chromic acid compound, a phosphoric acid compound, and an aminated phenol polymer 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. For example, if the above chromate treatment is performed, a chromic acid compound is present per 1 m ² of the surface of the metal layer 3. About 0.5 mg to about 50 mg, preferably about 1.0 mg to about 40 mg in terms of chromium, about 0.5 mg to about 50 mg, preferably about 1.0 mg to about 40 mg in terms of phosphorus, and aminated phenol weight It is desirable that the coalescence is contained at a ratio of about 1 mg to about 200 mg, preferably about 5.0 mg to 150 mg.

  In the chemical conversion treatment, a solution containing a compound used for forming an acid-resistant film is applied to the surface of the metal layer by a bar coating method, a roll coating method, a gravure coating method, an immersion method, or the like, and then the temperature of the metal layer is 70. It is carried out by heating so as to have a temperature of from about 0 to 200 ° C. Further, before the chemical conversion treatment is performed on the metal layer, the metal layer 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 treatment in this way, 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 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 And a random copolymer (for example, 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 by block polymerization or graft polymerization with 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, carboxylic acid-modified polyolefin is preferable; carboxylic acid-modified polypropylene is more preferable.

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

  In addition, the thickness of the sealant layer 4 is not particularly limited as long as it functions as a sealant layer. For example, the thickness is about 10 to 100 μm, preferably about 15 to 50 μm.

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

  The adhesive layer 5 is formed of an adhesive capable of bonding the metal layer 3 and the sealant layer 4. With respect to the adhesive used for forming the adhesive layer 5, the adhesive mechanism, the types of adhesive components, and the like are the same as those of the adhesive layer 2. The adhesive component used for the adhesive layer 5 is preferably a polyolefin resin, more preferably a carboxylic acid-modified polyolefin, particularly preferably a carboxylic acid-modified polypropylene.

  Although it will not restrict | limit especially if the thickness of the contact bonding layer 5 exhibits the function as a contact bonding layer, For example, about 2-50 micrometers, Preferably about 15-30 micrometers is mentioned.

[Coating layer]
In the battery packaging material of the present invention, for the purpose of improving design properties, electrolytic solution resistance, scratch resistance, moldability, etc., the base material layer 1 may be formed on the base material layer 1 as necessary (the metal layer of the base material layer 1). If necessary, a coating layer may be provided on the side opposite to (3). The coating layer is a layer located on the outermost layer when the battery is assembled.

  The coating layer can be formed of, for example, polyvinylidene chloride, polyester resin, urethane resin, acrylic resin, epoxy resin, or the like. Among these, the coating layer is preferably formed of a two-component curable resin. Examples of the two-component curable resin for forming the coating layer include a two-component curable urethane resin, a two-component curable polyester resin, and a two-component curable epoxy resin. Moreover, you may mix | blend a matting agent with a coating layer.

  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. Specific examples of the matting agent include talc, silica, graphite, kaolin, montmorilloid, montmorillonite, synthetic mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, and aluminum oxide. , Neodymium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, alumina, carbon black, carbon nanotubes, High melting point nylon, crosslinked acrylic, crosslinked styrene, crosslinked polyethylene, benzoguanamine, gold, aluminum, copper, nickel and the like can be mentioned. 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.

  The method for forming the coating layer is not particularly limited, and examples thereof include a method of applying a two-component curable resin for forming the coating layer on one surface of the base material layer 1. When the matting agent is blended, the matting agent may be added to the two-component curable resin, mixed, and then applied.

  Although it will not restrict | limit especially if said function as a coating layer is exhibited as a thickness of a coating layer, For example, about 0.5-10 micrometers, Preferably about 1-5 micrometers is mentioned.

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 in which layers having a predetermined composition are laminated is obtained. For example, the following method is exemplified. .

  First, a laminate in which the base material layer 1, the adhesive layer 2, and the metal layer 3 are laminated in order (hereinafter also referred to as “laminate A”) is formed. Specifically, the laminate A is formed by extruding an adhesive used for forming the adhesive layer 2 on the base layer 1 or the metal layer 3 whose surface is subjected to chemical conversion treatment, if necessary. It can be performed by a dry lamination method in which the metal layer 3 or the base material layer 1 is laminated and the adhesive layer 2 is cured after being applied and dried by a coating method such as a method or a roll coating method.

  Next, 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 constituting 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. . In the case where 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. (2) A method of separately forming a laminate in which the adhesive layer 5 and the sealant layer 4 are laminated, and laminating the laminate on the metal layer 3 of the laminate A by a thermal lamination method, 3) An adhesive for forming the adhesive layer 5 is laminated on the metal layer 3 of the laminate A by an extrusion method or a solution-coated high temperature drying and baking method, and a sheet-like shape is formed on the adhesive layer 5 in advance. (4) A melted adhesive layer 5 is placed between the metal layer 3 of the laminate A and the sealant layer 4 previously formed into a sheet shape. Adhesive layer 5 while pouring Method (sand lamination method) and the like to bond the laminate A and the sealant layer 4.

  When providing a coating layer, a coating layer is laminated | stacked on the surface on the opposite side to the metal layer 3 of the base material layer 1. FIG. The coating layer can be formed, for example, by applying the above-described resin for forming the coating layer to the surface of the base material layer 1. The order of the step of laminating the metal layer 3 on the surface of the base material layer 1 and the step of laminating the coating layer on the surface of the base material layer 1 are not particularly limited. For example, after forming a coating layer on the surface of the base material layer 1, the metal layer 3 may be formed on the surface of the base material layer 1 opposite to the coating layer.

  As described above, base material layer 1 / adhesive layer 2 / metal layer 3 whose surface is subjected to chemical conversion treatment as required / adhesive layer 5 provided as needed / sealant layer 4 / coating provided as needed In order to strengthen the adhesiveness of the adhesive layer 2 and the adhesive layer 5 provided as necessary, a hot roll contact type, a hot air type, a near or far infrared type, etc. You may use for the heat processing of. Examples of such heat treatment conditions include 150 to 250 ° C. for 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, 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.

Example 1-5 and Comparative Example 1-4
<Manufacture of battery packaging materials>
First, using the following resin films A to I as a resin film for forming the base material layer 1, a laminate in which base material layer 1 / adhesion layer 2 / metal layer 3 was laminated in order was produced. Specifically, the following adhesive layer 2 is formed on one surface of the base material layer 1 so as to have a thickness of 3 μm, and the following chemical conversion treatment surface of the metal layer 3 is pressure-heat bonded to the base material layer 1. A laminate in which / adhesive layer 2 / metal layer 3 was laminated in order was produced. In addition, in the resin films A to G forming the base material layer 1, the polyethylene terephthalate resin layer was positioned in the outermost layer on the side opposite to the sealant layer 4 of the base material layer 1.

  Separately, by coextruding an acid-modified polypropylene resin constituting the adhesive layer 5 (unsaturated carboxylic acid graft-modified random polypropylene graft-modified with an unsaturated carboxylic acid) and a polypropylene constituting the sealant layer 4 (random copolymer), A two-layer coextruded film consisting of the adhesive layer 5 and the sealant layer 4 was produced. Next, the metal layer 3 was laminated so that the adhesive layer 5 of the two-layer coextruded film prepared above was in contact with the metal layer of the laminate composed of the base material layer 1 / adhesive layer 2 / metal layer 3 prepared above. Was heated to 120 ° C. and thermal lamination was performed to obtain a laminate in which base layer 1 / adhesive layer 2 / metal layer 3 / adhesive layer 5 / sealant layer 4 were laminated in this order. After cooling the obtained laminate once, it is heated to 180 ° C., and the temperature is maintained for 1 minute to perform heat treatment, whereby the battery packaging materials of Example 1-5 and Comparative Example 1-4 are obtained. Obtained.

(Base material layer 1)
Resin film A
Polyethylene terephthalate resin and nylon 6 were extruded by a T-die method to produce a coextruded film, biaxially stretched in the MD and TD directions by a sequential stretching method, and then heat treated at 200 ° C. The draw ratio was such that the flow direction (MD) was 3.4 times and the width direction (TD) was 3.8 times. The laminated structure of the resin film A is polyethylene terephthalate (5 μm) / nylon 6 (20 μm).

Resin films B to D, F, G
Polyethylene terephthalate resin, thermoplastic polyester elastomer and nylon 6 were extruded by the T-die method to produce a co-extruded film, biaxially stretched in the MD and TD directions by the sequential stretching method, and then manufactured by heat treatment at 200 ° C. . The draw ratio and the laminated structure are as follows. The laminated structure of the resin films B to D, F, and G is polyethylene terephthalate (5 μm) / adhesive layer (1 μm) / nylon 6 (20 μm).
Resin film B: Flow direction (MD) 3.4 times, width direction (TD) 3.8 times Resin film C: Flow direction (MD) 3.6 times, width direction (TD) 3.6 times Resin film D: Flow direction (MD) 3.4 times, width direction (TD) 3.4 times Resin film F: Flow direction (MD) 3.0 times, width direction (TD) 3.4 times Resin film G: Flow direction (MD ) 3.2 times, width direction (TD) 3.8 times

Resin film E
An unstretched raw film made of a raw material mainly composed of polyethylene terephthalate is sequentially biaxially stretched in the flow direction (MD) 3.2 times and the width direction (TD) 3.2 times by the tenter method, and then heat treated at 210 ° C. A biaxially stretched polyethylene terephthalate film produced by the above process and an unstretched raw film made of a raw material mainly composed of nylon 6 are flow direction (MD) 3.0 times and width direction (TD) 3.3 by a tubular method. A biaxially stretched nylon film produced by simultaneous biaxial stretching at twice and heat treatment at 200 ° C. was produced by dry laminating with an adhesive. The laminated structure of the resin film E is polyethylene terephthalate (9 μm) / adhesive layer (3 μm) / nylon 6 (15 μm).

Resin film H
An unstretched raw film made of a raw material mainly composed of nylon 6 is manufactured by simultaneous biaxial stretching by a tubular method and then heat-treating at 200 ° C. The draw ratio was manufactured under conditions of a flow direction (MD) of 3.0 times and a width direction (TD) of 3.3 times. The resin film H is formed of one layer of nylon 6 film (25 μm).

Resin film I
An unstretched raw film made of a raw material containing polyethylene terephthalate as a main component is manufactured by sequentially biaxially stretching by a tenter method and then heat-treating at 210 ° C. The draw ratio was manufactured under conditions of 3.2 times in the flow direction (MD) and 3.2 times in the width direction (TD). The resin film I is formed of a single layer of polyethylene terephthalate film (12 μm).

(Metal layer 3)
An aluminum foil (ALM1: 8021 material) having the following physical properties was used. The tensile rupture strength and the tensile rupture elongation are values measured by methods based on JIS K7127, respectively. The 0.2% proof stress is a value measured by a tensile test specified in JIS Z 2241.
・ Tensile fracture strength: MD direction 102.2MPa, TD direction 100.9MPa
-Tensile elongation at break: 9.8% in MD direction, 9.5% in TD direction
0.2% yield strength: MD direction 70.8 MPa, TD direction 68.5 MPa

(Adhesive layer 2)
The following adhesives were used as the adhesive layer 2 for adhering the base material layer 1 and the metal layer 3.
Trimethylolpropane (TMP) adduct of a polyol compound and toluene diisocyanate (TDI) having a glass transition point of −5 to 5 ° C., a weight average molecular weight of 10 to 40 × 10 ³ , and a hydroxyl group equivalent of 0.7 to 1.9 / mol. Resin-based adhesive in which an aromatic isocyanate mainly composed of styrene is mixed at a ratio of 1: 3

<Measurement of tensile breaking elongation and tensile breaking strength>
The tensile rupture elongation and tensile rupture strength of the battery packaging material obtained above were measured by methods in accordance with the provisions of JIS K7127, respectively. The measurement conditions were a sample width of 15 mm, a distance between marked lines of 50 mm, and a tensile speed of 100 mm / min. The results are shown in Table 1.

<Evaluation of formability>
The battery packaging material obtained above was cut into 120 × 80 mm strips, which were used as test samples. Using a straight mold composed of a 30 × 50 mm rectangular male mold and a female mold with a clearance of 0.5 mm between the male mold and the above, the thermal adhesive resin layer side is positioned on the male mold side. The test sample was placed, and the test sample was pressed with a presser pressure (surface pressure) of 0.1 MPa so as to have a molding depth of 7 mm and 8 mm, respectively, and cold-molded (drawn one-stage molding). The presence or absence of pinholes and cracks in the metal layer in the molded battery packaging material was confirmed, and the pinhole and crack generation rates (%) were calculated. The rate of occurrence of pinholes and cracks was determined when molding was performed when 30 test samples were molded under the above conditions, with pinholes or cracks observed even at one location after molding as a defective molding. Calculated as the percentage of defective products. The results are shown in Table 1.

<Evaluation of electrolyte resistance>
The electrolyte solution (ethylene carbonate: diethyl carbonate: dimethyl carbonate = 1: 1: 1 solution of 1 mol phosphorus hexafluoride added to the surface of the base material layer 1 side of the battery packaging material obtained above with 1000 ppm of water. 3 cc of lithium acid was added, and after 30 minutes, the electrolyte was dropped with a wipe soaked in isopropyl alcohol (IPA), and the surface of the battery packaging material was visually observed to see if it was whitened. did. The results are shown in Table 1.

  As is apparent from the results shown in Table 1, the base material layer 1 includes a polyester resin layer and a polyamide resin layer even when molded under a very severe condition of a molding depth of 7 mm and further a molding depth of 8 mm. It is formed of a biaxially stretched film, and the tensile break elongation in the MD direction and the TD direction of the base material layer 1 is in the range of 85 to 130%, and the tensile break elongation in the TD direction of the base material layer 1 is In the battery packaging material of Example 1-5 in which the ratio of tensile elongation at break (MD / TD) in the MD direction is in the range of 1.0 to 1.4, no pinholes and cracks are observed. The occurrence of cracks was remarkably suppressed. Moreover, in the battery packaging material of Example 1-5, the resistance to electrolytic solution was also excellent. On the other hand, although the base material layer 1 is formed of a biaxially stretched film including a polyester resin layer and a polyamide resin layer, the battery packaging material of Comparative Example 1-2 that does not satisfy the above-described requirements for tensile elongation at break Then, although it was excellent in electrolytic solution resistance, it was inferior in moldability. In particular, when molding was performed under very severe conditions of a molding depth of 8 mm, the pinhole occurrence rate was very high. Moreover, in the battery packaging material of Comparative Example 3 in which the base material layer 1 was formed of a nylon film, the moldability was very excellent, but the electrolytic solution resistance was poor. On the other hand, in the battery packaging material of Comparative Example 4 in which the base material layer 1 was formed of polyethylene terephthalate, the electrolytic solution resistance was excellent, but the moldability was very poor.

DESCRIPTION OF SYMBOLS 1 Base material layer 1a Polyester resin layer 1b Polyamide resin layer 1c Adhesive resin layer 2 Adhesive layer 3 Metal layer 4 Sealant layer 5 Adhesive layer

Claims (9)

It consists of a laminate in which at least a base material layer, an adhesive layer, a metal layer, and a sealant layer are sequentially laminated,
The base material layer is formed of a biaxially stretched film including at least a polyester resin layer and a polyamide resin layer,
The tensile break elongation in MD direction and TD direction of the base material layer is in the range of 85 to 130%,
The ratio of the tensile elongation at break in the MD direction to the tensile elongation at break in the TD direction of the base layer (MD / TD) is, Ri range near the 1.0 to 1.4,
Breaking strength Tensile in MD and TD directions of the substrate layer, Ru der both 250MPa or more, the packaging material for a battery.   The battery packaging material according to claim 1, wherein the base material layer is formed of a biaxially stretched film formed by coextruding at least a polyester resin and a polyamide resin.   The battery packaging material according to claim 1 or 2, wherein the base material layer is formed of a biaxially stretched film in which a polyester resin layer, an adhesive resin layer, and a polyamide resin layer are laminated in this order.   The battery packaging material according to any one of claims 1 to 3, wherein in the base material layer, the polyester resin layer is located in an outermost layer opposite to the sealant layer. The ratio of the tensile break strength in the MD direction to the tensile strength at break in the TD direction of the base layer (MD / TD) is in the range of 0.8 to 1.1, according to any of claims 1-4 Battery packaging material. The metal layer has a 0.2% proof stress when a tensile test in a direction parallel to the MD direction and a 0.2% proof stress when a tensile test in a direction parallel to the TD direction are performed. both an aluminum foil in the range of 55~140N / mm ^2, a battery packaging material according to any of claims 1-5. Chemical conversion treatment on at least one surface of the metal layer is applied, the packaging material for a battery according to any one of claims 1-6. The battery packaging material according to any one of claims 1 to 7 , which is a packaging material for a secondary battery. At least a positive electrode, a negative electrode, and a battery device having an electrolyte is housed in the battery packaging the material according to any one of claims 1-8, battery.