JP6736837B2 - Battery packaging material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a battery packaging material which is less likely to cause pinholes and cracks during molding and has excellent moldability.

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

Therefore, in recent years, a film-shaped laminate in which a base material/metal layer/sealant layer is sequentially laminated has been proposed as a battery packaging material that can be easily processed into various shapes and can be made thin and lightweight. There is.

In addition, in such a battery packaging material, generally, a recess is formed by cold forming, a battery element such as an electrode or an electrolytic solution is arranged in a space formed by the recess, and the sealant layers are heated together. By fusing, a battery in which the battery element is housed inside the battery packaging material is obtained. However, such a film-shaped packaging material has a drawback that it is thinner than a metallic packaging material and pinholes and cracks are likely to occur during molding. If pinholes or cracks occur in the battery packaging material, the electrolytic solution may penetrate into the metal layer and form metal deposits, resulting in a short circuit. It is indispensable for a battery packaging material to have a property that pinholes are unlikely to occur during molding, that is, excellent moldability.

For example, in Patent Document 1, in a laminated packaging material including an inner layer made of a resin film, a first adhesive layer, a metal layer, a second adhesive layer, and an outer layer made of a resin film, the first adhesive layer And at least one of the second adhesive layer is formed of an adhesive composition containing a resin having an active hydrogen group in a side chain, a polyfunctional isocyanate, and a polyfunctional amine compound, thereby providing reliability for deeper molding. It is disclosed that a packaging material having high properties can be obtained.

JP 2008-287971 A

In recent years, with the demand for smaller and thinner batteries, there has been a demand for further thinning of battery packaging materials. However, when the thickness of the battery packaging material is thin, there is a problem that pinholes and cracks are likely to occur in the metal layer during molding.

In particular, as a result of studies by the present inventors, it became clear that in a battery packaging material in which a base material layer containing nylon is laminated with a metal layer, the occurrence of pinholes and the like due to the reduced thickness becomes remarkable. It was

Under these circumstances, the main object of the present invention is to provide a battery packaging material comprising a laminate in which at least a base material layer containing nylon, an adhesive layer, a metal layer, and a sealant layer are sequentially laminated. It is an object of the present invention to provide a battery packaging material that is less likely to cause holes and cracks and has excellent moldability.

The present inventor has conducted extensive studies in order to solve the above problems. As a result, in a battery packaging material comprising a laminate in which at least a base material layer containing nylon, a metal layer, and a sealant layer are sequentially stacked, JIS Z1707 of the base material layer with respect to the thickness B of the base material layer: By setting the ratio (A/B) of the puncture strength A measured by the method conforming to the 1997 regulations to 0.92 N/μm or more, pinholes and cracks are less likely to occur during molding, and excellent moldability It has been found that it becomes a packaging material for batteries provided with. The present invention has been completed by further studies based on these 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 containing nylon, a metal layer, and a sealant layer consisting of a laminate sequentially laminated,
The ratio (A/B) of the puncture strength A of the base material layer measured by a method according to the JIS Z1707:1997 standard of the base material layer to the thickness B of the base material layer is 0.92N. /Μm or more, a battery packaging material.
Item 2. Item 2. The battery packaging material according to Item 1, wherein the base material layer includes a layer formed of nylon.
Item 3. Item 3. The battery packaging material according to Item 1 or 2, wherein the base material layer is composed of a laminate of a layer containing polyester and a layer containing nylon.
Item 4. Item 4. The battery packaging material according to any one of Items 1 to 3, wherein at least one surface of the metal layer is subjected to a chemical conversion treatment.
Item 5. Item 5. The battery packaging material according to any one of Items 1 to 4, wherein the metal layer is formed of an aluminum foil.
Item 6. Item 6. The battery packaging material according to any one of Items 1 to 5, wherein the metal layer has a thickness in the range of 10 to 50 µm.
Item 7. Item 7. The battery packaging material according to any one of Items 1 to 6, wherein the thickness of the laminate is 160 µm or less.
Item 8. 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 7.
Item 9. At least, a step of obtaining a laminated body in which a base material layer containing nylon, a metal layer, and a sealant layer are sequentially laminated,
As the base material layer, the ratio (A/B) of the puncture strength A to the thickness B of the base material layer measured by a method in conformity with JIS Z1707:1997 of the base material layer is 0.92N. /Μm or more, a method of manufacturing a packaging material for a battery using a material.

According to the present invention, in a battery packaging material comprising a laminate in which at least a base material layer containing nylon, a metal layer, and a sealant layer are sequentially stacked, the thickness of the base material layer relative to the thickness B of the base material layer is By setting the ratio (A/B) of the puncture strength A measured by the method according to JIS Z1707:1997 to 0.92 N/μm or more, pinholes and cracks are less likely to occur during molding, which is excellent. It is possible to provide a battery packaging material having excellent moldability.

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 layer containing nylon, a metal layer, and a sealant layer are sequentially laminated, and the base layer has the above-mentioned base with respect to the thickness B of the base layer. The material layer is characterized in that the ratio (A/B) of the puncture strength A measured by the method in conformity with JIS Z1707:1997 is 0.92 N/μm or more. 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, 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 located on the periphery of the battery element are thermally welded to each other to seal the battery element, thereby sealing the battery element.

In the battery packaging material of the present invention, as shown in FIG. 1, an adhesive layer 2 is provided between the base material layer 1 and the metal layer 3 for the purpose of enhancing the adhesiveness thereof, if necessary. Good. In the battery packaging material of the present invention, as shown in FIG. 2, an adhesive layer 5 is provided between the metal layer 3 and the sealant layer 4, if necessary, for the purpose of enhancing the adhesiveness between them. May be.

The thickness of the laminate constituting the battery packaging material of the present invention is not particularly limited, but from the viewpoint of improving the moldability while reducing the thickness, preferably 160 μm or less, more preferably about 50 to 90 μm. To be According to the present invention, the occurrence of pinholes and the like due to molding can be effectively suppressed even when the thickness of the laminate constituting the battery packaging material of the present invention is very thin, for example, 80 μm or less. Therefore, the battery packaging material of the present invention can contribute to the improvement of the energy density of the battery.

2. 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. The base material layer 1 contains nylon. As described above, in recent years, along with the demand for smaller and thinner batteries, there has been a demand for even thinner battery packaging materials. However, when the thickness of the battery packaging material is thin, there is a problem that pinholes and cracks are likely to occur in the metal layer during molding. In particular, as a result of studies by the present inventors, it has been revealed that pinholes are significantly generated due to the reduced thickness in a battery packaging material in which a base layer containing nylon is laminated with a metal layer. ..

On the other hand, in the present invention, the ratio (A/B) of the puncture strength A to the thickness B of the base material layer 1 measured by the method according to JIS Z1707:1997 of the base material layer 1 is , 0.92 N/μm or more, generation of pinholes and cracks in the metal layer 3 is effectively suppressed. When the ratio of the puncture strength A to the thickness B of the base material layer 1 (that is, the size of the puncture strength per unit thickness) is equal to or more than a predetermined value, generation of pinholes or the like in the metal layer 3 is suppressed. Although details of the details of the mechanism are not clear, it can be considered as follows, for example. That is, in the present invention, by using a base material layer having a greater puncture strength per unit thickness than a conventionally used base material layer made of nylon, the metal layer 3 at the time of molding is used. It is considered that the rapid elongation of the metal layer 3 is appropriately controlled by the base material layer 1, and as a result, the occurrence of pinholes and the like in the metal layer 3 is suppressed.

The ratio (A/B) of the puncture strength A measured by the method according to JIS Z1707:1997 of the base material layer 1 to the thickness B of the base material layer 1 should be 0.92 N/μm or more. From the viewpoint of further improving moldability, it is preferably about 0.94 to 0.98 N/μm.

The material forming the base material layer 1 contains nylon and is not particularly limited as long as it has the above-mentioned puncture strength. The base material layer 1 preferably includes a layer formed of nylon. Specific examples of nylon preferably include nylon 6, nylon 6,6, a copolymer of nylon 6 and nylon 6,6, nylon 6,10, and the like. The material forming the base material layer 1 may include a resin other than nylon. Examples of other resins include polyester resins, polyamide resins (excluding nylon), epoxy resins, acrylic resins, fluororesins, polyurethane resins, silicon resins, phenol resins, and mixtures and copolymers thereof. The material forming the base material layer 1 may be one kind alone or a combination of two or more kinds.

In addition, the base material layer 1 may be composed of a laminate of a layer containing polyester and a layer containing nylon. Specific examples of the polyester include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, and the like, and biaxially stretched polyester is preferable. Further, the layer containing nylon is preferably formed of nylon. In the laminate, it is preferable that the layer containing polyester is located on the outermost layer side (the side opposite to the metal layer 3) and the layer containing nylon is located on the inner layer side (metal layer 3 side).

The base material layer 1 is preferably a resin film formed of the above materials. In addition, for example, when the base material layer 1 is formed of a two-layer resin film, it is preferable to have a structure of a layer containing polyester/a layer containing nylon.

When the base material layer 1 is formed of a multilayer resin film, two or more resin films may be laminated via an adhesive component such as an adhesive or an adhesive resin, and the type and amount of the adhesive component used, etc. Is the same as that of the adhesive layer 2 described later. The method for laminating the two or more resin films is not particularly limited, and a known method can be adopted. Examples thereof include a dry lamination method and a sand lamination method, and a dry lamination method is preferable. When laminating by a dry lamination method, it is preferable to use a urethane adhesive as the adhesive layer. At this time, the thickness of the adhesive layer is, for example, about 2 to 5 μm.

In the present invention, a lubricant is preferably attached to the surface of the base material layer 1 from the viewpoint of enhancing the moldability of the battery packaging material. The lubricant is not particularly limited, but preferably an amide lubricant is used. Specific examples of the amide-based lubricant include saturated fatty acid amide, unsaturated fatty acid amide, substituted amide, methylolamide, saturated fatty acid bisamide, unsaturated fatty acid bisamide, and the like. Specific examples of the saturated fatty acid amide include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, and hydroxystearic acid amide. Specific examples of unsaturated fatty acid amides include oleic acid amide and erucic acid amide. Specific examples of the substituted amide include N-oleylpaltimic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, and N-stearyl erucic acid amide. Specific examples of methylolamide include methylolstearic acid amide. Specific examples of the saturated fatty acid bisamide include methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, ethylenebisstearic acid amide, ethylenebishydroxystearic acid amide, ethylenebisbehenic acid amide, and hexamethylenebisstearic acid amide. Examples thereof include acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N,N′-distearyl adipic acid amide, and N,N′-distearyl sebacic acid amide. Specific examples of the unsaturated fatty acid bisamide include ethylene bisoleic acid amide, ethylene bis erucic acid amide, hexamethylene bis oleic acid amide, N,N′-dioleyl adipate amide, N,N′-dioleyl sebacic acid amide. And so on. Specific examples of the fatty acid ester amide include stearoamide ethyl stearate. Specific examples of aromatic bisamides include m-xylylenebisstearic acid amide, m-xylylenebishydroxystearic acid amide, and N,N'-cystearylisophthalic acid amide. The lubricant may be used alone or in combination of two or more.

The thickness of the base material layer 1 is not particularly limited as long as the battery packaging material satisfies the above puncture strength while exhibiting the function as the base material layer, but is, for example, about 10 to 50 μm, preferably 10 to 35 μm. The degree can be 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 that can bond the base layer 1 and the metal layer 3 together. The adhesive used for forming the adhesive layer 2 may be a two-component curable adhesive or a one-component curable adhesive. 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 heat pressure type and the like.

Specific examples of the adhesive component 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-based adhesives; Polyurethane-based adhesives; Epoxy-based resins; Phenolic resin-based resins; Nylon 6, nylon 66, nylon 12, polyamide-based resins such as copolyamides; Polyolefins, carboxylic acid-modified polyolefins, metal-modified polyolefins, and other polyolefins -Based resins, polyvinyl acetate-based resins; cellulose-based adhesives; (meth)acrylic-based resins; polyimide-based resins; amino resins such as urea resins and melamine resins; rubbers such as chloroprene rubber, nitrile rubber, styrene-butadiene rubber; silicones Examples include resin based resins. These adhesive components may be used alone or in combination of two or more. Among these adhesive components, a polyurethane adhesive is preferable.

The thickness of the adhesive layer 2 is not particularly limited as long as it functions as an adhesive layer, but is, for example, about 1 to 10 μm, preferably about 2 to 5 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 or metal vapor deposition, and is preferably formed of a metal foil, more preferably an 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, 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 as long as it functions as a barrier layer against water vapor and the like, but may be, for example, about 10 μm to 50 μm, preferably about 10 μm to 40 μm.

Further, 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. As the chemical conversion treatment, for example, 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, polyphosphoric acid; aminated phenol having repeating units represented by the following general formulas (1) to (4) Examples include chromate treatment using a polymer. In the aminated phenol polymer, the repeating units represented by the following general formulas (1) to (4) may be contained alone or in any combination of two or more. Good.

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. The hydroxyalkyl group represented by X, R ¹ and R ² includes, for example, hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 1-hydroxypropyl group, 2-hydroxypropyl group, 3-hydroxy 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 the 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, for example, preferably 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, or 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. A resin layer obtained by crosslinking a cationic polymer with a crosslinking agent may be further formed on the anticorrosion treated layer. Here, as the cationic polymer, for example, 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, 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 of about 0.5 mg to about 50 mg, preferably about 1.0 mg to about 40 mg, phosphorus compound conversion of 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 way, the chemical conversion treatment of the surface of the metal layer can be performed more efficiently.

[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. Are listed. 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 α,β with respect to the cyclic polyolefin. -A polymer obtained by block-polymerizing or graft-polymerizing an unsaturated carboxylic acid or its anhydride. 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. Furthermore, 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.

The sealant layer 4 preferably contains a compatible elastomer in which the dispersed phase size is 1 nm or more and less than 1 μm. More specifically, in the sealant layer 4, the compatible elastomer is preferably dispersed in the resin composition forming the sealant layer 4 with a dispersed phase size of 1 nm or more and less than 1 μm. In the sealant layer 4, the compatible elastomer is preferably dispersed in at least one of the acid-modified polyolefin and the acid-modified cyclic polyolefin with a dispersed phase size of 1 nm or more and less than 1 μm.

Such a compatible elastomer has a so-called micro phase separation structure as disclosed in JP 2013-258162 A. Specifically, the microphase-separated structure has a maximum diameter (d1) of 1 to 200 nm when the disperse phase (either the flexible component or the constraining component) in the (1) compatible elastomer is approximated as an ellipse. Or (2) the ratio (d1/d2) of the maximum diameter (d1) of the dispersed phase (either the flexible component or the constraining component) domain to the maximum value (d2) of the diameter orthogonal to this maximum diameter is 20 The layered lamella structure is in the above-mentioned rod shape, and the maximum value (d2) is 1 to 200 nm, or (3) it is impossible to determine which of the flexible component and the constraining component is the dispersed phase. And the thickness of at least one layer is 1 to 200 nm.

The confirmation of the micro phase separation structure in the compatible elastomer can be carried out by a known method as disclosed in JP 2013-258162 A, and specifically, it is carried out as follows. A resin composition containing a compatible elastomer is press-molded into small pieces of 0.5 mm square and dyed with ruthenic acid (RuO ₄ ). Using this, an ultramicrotome equipped with a diamond knife (such as REICHERTS S and REICHERT TCS) is used to prepare an ultrathin section having a film thickness of about 100 nm. Next, carbon is vapor-deposited on this ultrathin section and observed with a transmission electron microscope. At least five observation points are randomly selected and observed at a magnification of 10,000 times, 50,000 times, and 150,000 times. At that time, when the approximation as the ellipse of (1) is performed, the software of Image-Pro Plus is used in the field of view observed with a transmission electron microscope at 10,000 to 150,000 times, and the Axis- By selecting major, the disperse phase (either the flexible component or the constrained component) is approximated to an ellipse having the same area and the same first and second moments, and its major axis is the maximum diameter (d1).

When the compatible elastomer is present in the acid-modified polyolefin resin or the acid-modified cyclic polyolefin, it is preferably dispersed in a dispersed phase size of 1 nm or more and less than 1 μm. The dispersed phase size of the compatible elastomer is preferably 1 nm or more and 200 nm or less from the viewpoint of further improving the insulating property. The dispersed phase size of the elastomer in the sealant layer 4 in the present invention is the diameter when the dispersed phase can be regarded as a circular shape, the maximum diameter when it can be approximated as an ellipse, and the maximum diameter of the major axis of the aspect ratio when it is a rod shape. In the case of a layered lamella structure, it is the thickness of the layer.

The compatible elastomer is not particularly limited as long as it is dispersed in the sealant layer 4 with a dispersed phase size of 1 nm or more and less than 1 μm, and preferably a propylene-α olefin copolymer elastomer is used. The compatible elastomer may be used alone or in combination of two or more. The propylene-α-olefin copolymer elastomer has a structural unit derived from propylene and a structural unit derived from at least one selected from α-olefins having 2 to 20 carbon atoms (excluding propylene), A copolymer elastomer in which the proportion of structural units derived from is 51 mol% or more is preferable. Examples of commercially available propylene-α-olefin copolymer elastomers include Notio (trade name) manufactured by Mitsui Chemicals, Toughselen (trade name) manufactured by Sumitomo Chemical, and Dynaron (trade name) manufactured by JSR. Further, for example, an elastomer other than the propylene-α-olefin copolymer elastomer disclosed in JP-A-2003-321582 may be used.

When the sealant layer 4 contains a compatible elastomer, the content of the compatible elastomer in the sealant layer 4 is preferably about 1 to 60% by mass, more preferably about 10 to 50% by mass, and further preferably 15 to 45% by mass. %.

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

Moreover, the sealant layer 4 may include a lubricant and the like as necessary. When the sealant layer 4 contains a lubricant, the moldability of the battery packaging material can be improved. The lubricant is not particularly limited, and a known lubricant can be used, and examples thereof include those exemplified for the base material layer 1 above. The lubricant may be used singly or in combination of two or more. The content of the lubricant in the sealant layer 4 is not particularly limited, and from the viewpoint of enhancing the moldability and insulating properties of the electronic packaging material, it is preferably about 0.01 to 0.2% by mass, more preferably 0. It may be about 05 to 0.15% by mass.

[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 needed to firmly bond the metal layer 3 and the sealant layer 4.

The adhesive layer 5 is formed of an adhesive that can bond the metal layer 3 and the sealant layer 4 together. Regarding the adhesive used for forming the adhesive layer 5, the adhesive mechanism, the type of adhesive component, and the like are the same as in the case of the adhesive layer 2. The adhesive component used in the adhesive layer 5 is preferably a polyolefin resin, more preferably a carboxylic acid-modified polyolefin, and particularly preferably a carboxylic acid-modified polypropylene.

The thickness of the adhesive layer 5 is not particularly limited as long as it can function as an adhesive layer, but is, for example, about 2 to 50 μm, preferably about 10 to 40 μm.

[Coating layer]
In the battery packaging material of the present invention, if necessary, on the base material layer 1 (metal layer of the base material layer 1) for the purpose of improving designability, electrolytic solution resistance, scratch resistance, moldability, and the like. A coating layer (not shown) may be provided on the side opposite to 3) if necessary. The coating layer is 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. Of these, the coating layer is preferably formed of a two-component curable resin. Examples of the two-component curing type resin forming the coating layer include a two-component curing type urethane resin, a two-component curing type polyester resin, and a two-component curing type epoxy resin. A matting agent may be added to the 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, organic substances and the like. Also, the shape of the matting agent is not particularly limited, and examples thereof include a spherical shape, a fibrous shape, a plate shape, an amorphous shape, and a balloon shape. Specific examples of matting agents include talc, silica, graphite, kaolin, montmorillonite, montmorillonite, synthetic mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide. , Neodymium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, alumina, carbon black, carbon nanotubes, High melting point nylon, crosslinked acryl, crosslinked styrene, crosslinked polyethylene, benzoguanamine, gold, aluminum, copper, nickel and the like can be mentioned. These matting agents may be used alone or in combination of two or more. Among these matting agents, from the viewpoint of dispersion stability, cost, etc., preferable silica is silica, barium sulfate, and titanium oxide. Further, the matting agent may be subjected to various surface treatments such as insulation treatment and high dispersibility treatment on the surface.

The method of forming the coating layer is not particularly limited, and examples thereof include a method of applying the two-component curable resin forming the coating layer onto 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.

The thickness of the coating layer is not particularly limited as long as it exhibits the above-mentioned function as the coating layer, but is, for example, about 0.5 to 10 μm, preferably about 1 to 5 μm.

3. Method for producing battery packaging material For the method for producing a battery packaging material of the present invention, as long as a laminate obtained by laminating each layer of a predetermined composition is obtained, at least, at least, a base layer containing nylon, The method includes a step of obtaining a laminated body in which a metal layer and a sealant layer are sequentially laminated,
As the base material layer, the ratio (A/B) of the puncture strength A of the base material layer to the thickness B of the base material layer measured by a method in conformity with JIS Z1707:1997 is 0.92 N/ Those having a thickness of at least μm are used.
That is, as the base material layer 1, the base material layer 1 described in the section "2. Each layer forming the battery packaging material" is used to laminate the layers to manufacture the battery packaging material of the present invention. be able to.

An example of the method for producing the battery packaging material of the present invention is as follows. 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. To form the laminate A, specifically, 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 is applied by a gravure coating method or a roll method. This 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 coating 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. .. In addition, 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 co-extruded on the metal layer 3 of the laminate A to form a laminate. Method (coextrusion lamination method), (2) a method of separately forming a laminated body in which the adhesive layer 5 and the sealant layer 4 are laminated, and laminating this on the metal layer 3 of the laminated body A by the 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, a solution-coated drying method at a high temperature, or a baking method, and the adhesive layer 5 is preliminarily sheeted. A method of laminating the sealant layer 4 formed into a film by a 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.

When providing the coating layer, the coating layer is laminated on the surface of the base material layer 1 opposite to the metal layer 3. The coating layer can be formed, for example, by applying the above-mentioned resin 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 is 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, coating layer/base material layer 1/adhesive layer 2/metal layer 3 whose surface has been subjected to chemical conversion treatment/adhesive layer 5/sealant layer optionally provided/provided as necessary 4 is formed, but in order to strengthen the adhesiveness of the adhesive layer 2 and the adhesive layer 5 provided as necessary, a hot roll contact type, hot air type, near or far infrared type, etc. May be subjected to the heat treatment. 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, suitability for secondary processing of the final product (pouching, embossing), etc., if necessary. Therefore, surface activation treatment such as corona treatment, blast treatment, oxidation treatment, and 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 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 the battery packaging material of the present invention is used to house a battery element, the battery packaging material of the present invention is used such 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, 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.

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. The puncture strength of each nylon film used as the base material layer was determined by using the ZP-50N (force gauge) and MX-2-500N (measuring stand) manufactured by Imada Co., Ltd. according to JIS Z1707:1997. It was measured by the method.

Example 1-3 and Comparative Example 1-3
<Manufacture of battery packaging materials>
On each of the base material layers (thickness 15 μm or 25 μm) made of nylon films 1 to 6 (Ny1 to Ny6) having the puncture strength shown in Table 1, both surfaces were subjected to chemical conversion treatment (thickness 35 μm). Alternatively, a metal layer of 40 μm) was laminated by a dry lamination method. Specifically, a two-component urethane adhesive (polyol compound and aromatic isocyanate-based compound) was applied to one surface of the aluminum foil to form an adhesive layer (thickness 3 μm) on the metal layer. Next, after laminating the adhesive layer on the metal layer and the base material layer, aging treatment was carried out at 40° C. for 24 hours to prepare a base material layer/adhesive layer/metal layer laminate. The chemical conversion treatment of the aluminum foil used as the metal layer was performed by roll-coating a treatment liquid containing a phenol resin, a chromium fluoride compound, and phosphoric acid so that the amount of chromium applied was 10 mg/m ² (dry weight). It was applied to both sides of the aluminum foil by the method and baked for 20 seconds under the condition that the film temperature was 180° C. or higher. Next, by co-extruding 20 μm of carboxylic acid-modified polypropylene (disposed on the metal layer side) and 20 μm of random polypropylene (innermost layer) on the metal layer of the laminate, the adhesive layer/sealant layer was laminated on the metal layer. Thus, a packaging material for each battery was obtained. The layer structure of the battery packaging materials of Examples 1 and 2 and Comparative Examples 1 and 2 was as follows: base material layer (15 μm)/adhesive layer (3 μm)/metal layer (35 μm)/adhesive layer (25 μm)/sealant layer (20 μm). The layer structure of the battery packaging materials of Example 3 and Comparative Example 3 was: base material layer (25 μm)/adhesive layer (3 μm)/metal layer (40 μm)/adhesive layer (23 μm)/sealant layer (23 μm). is there.

In Table 1, the tensile strength at break and the tensile elongation at break of the base material layer 1 are values obtained by measurement by a method in accordance with JIS K7127.

(Evaluation of moldability)
Each of the battery packaging materials obtained above was cut into a rectangle of 80 mm×120 mm to prepare a sample. This sample was molded from a molding depth of 0.5 mm at a pressing pressure of 0.4 MPa using a molding mold (female mold) having a diameter of 30×50 mm and a corresponding molding mold (male mold). Cold forming was performed on 10 samples, each with a forming depth changed in units of 5 mm. Regarding the sample after cold forming, the deepest forming depth that does not generate pinholes and cracks in all 10 samples of the aluminum foil is Amm, and the deepest forming depth that pinholes occur in the aluminum foil, etc. The number of samples in which the occurrence of B was taken as B, and the value calculated by the following formula was taken as the molding depth of the battery packaging material. The results are shown in Table 2.
Molding depth = Amm + (0.5 mm/10 pieces) x (10 pieces-B pieces)

As is clear from the results shown in Table 2, when Examples 1 and 2 in which the thickness of the base material layer is 15 μm and Comparative Examples 1 and 2 are compared, the ratio of the puncture strength A to the thickness B of the base material layer (A In Examples 1 and 2 in which /B) is 0.92 N/μm or more, as compared with Comparative Examples 1 and 2 in which /B) is less than 0.92 N/μm, the forming depth is deep and the formability is excellent. .. Further, even when Example 3 in which the thickness of the base material layer is 25 μm and Comparative Example 3 are compared, the ratio (A/B) of the puncture strength A to the thickness B of the base material layer is 0.92 N/μm or more. In Comparative Example 3, which is less than 0.92 N/μm, the molding depth was deep and the moldability was excellent, as compared with Comparative Example 3.

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

Claims (7)

At least, the base layer, a metal layer, and Ri battery packaging material der constructed from a laminate sealant layer sequentially laminated,
The substrate layer is formed of a nylon film, or is a laminate of a layer formed of a nylon film and a layer formed of a polyester film,
The base material layer has a thickness of 10 μm or more,
The ratio (A/B) of the puncture strength A of the base material layer measured by a method according to the JIS Z1707:1997 standard of the base material layer to the thickness B of the base material layer is 0.92N. /Μm or more,
The packaging material for batteries, wherein the thickness of the laminate constituting the packaging material for batteries is 50 μm or more. The battery packaging material according to claim 1, wherein at least one surface of the metal layer is subjected to a chemical conversion treatment. The packaging material for a battery according to claim 1, wherein the metal layer is formed of an aluminum foil. The battery packaging material according to claim 1, wherein the metal layer has a thickness in the range of 10 to 40 μm. The thickness of the said laminated body which comprises the said packaging material for batteries is 160 micrometers or less, The packaging material for batteries in any one of Claims 1-4. 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. At least a base material layer, a metal layer, and a method for producing a battery packaging material composed of a laminate in which a sealant layer is sequentially laminated,
At least, the base layer, the metal layer, and comprises a step of obtaining the laminate the sealant layer are sequentially laminated,
The substrate layer is formed of a nylon film, or is a laminate of a layer formed of a nylon film and a layer formed of a polyester film,
The base material layer has a thickness of 10 μm or more,
As the base material layer, the ratio (A/B) of the puncture strength A to the thickness B of the base material layer, which is measured by a method in conformity with JIS Z1707:1997 of the base material layer, is 0.92N. /Μm or more,
The method for producing a battery packaging material, wherein the laminate constituting the battery packaging material has a thickness of 50 μm or more.