JP6592922B2 - Battery packaging materials - Google Patents

Description

  The present invention relates to a battery packaging material in which a wavy shape does not remain at an end portion after molding, and the occurrence of poor sealing can be effectively suppressed.

  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. (For example, refer to Patent Document 1).

  Such a packaging material for a battery is generally manufactured as a strip-shaped laminated film in a production line, and is a wound body obtained by winding the film into a roll. Further, the laminated film is unwound from the wound body, and the laminated film is cut in the unwinding direction (length direction) to be wound up again as a laminated film having a desired length in the width direction. It is commercialized as a body.

  In recent years, battery packaging materials are required to be thinner and lighter. However, for example, when the thickness of the metal layer is reduced to about 30 μm or less, the so-called “stiffness” of the battery packaging material is reduced, and when the laminated film is cut in the unwinding direction (length direction) as described above, A wavy shape in which the end portion of the subsequent laminated film undulates along the length direction is likely to occur.

  The battery packaging material is used for drawing or the like in order to form a space for enclosing the battery element. Conventionally, when a wavy shape is present at the end of the battery packaging material after cutting, However, there is a problem that the wavy shape remains and causes a sealing failure of the battery packaging material.

JP 2008-287971 A

  The main object of the present invention is a battery packaging material in which at least a base material layer, a metal layer, and a sealant layer are laminated in order, and the metal layer has a thickness of 30 μm or less, and is formed after molding. It is an object of the present invention to provide a battery packaging material in which the wavy shape does not remain at the end of the battery and can effectively suppress the occurrence of a sealing failure.

  The present inventor has intensively studied to solve the above problems. As a result, at least a base material layer, a metal layer, and a sealant layer are sequentially laminated in a battery packaging material, the thickness of the metal layer is 30 μm or less, and the end in the width direction of the battery packaging material is A straight line that has a corrugated shape that undulates along the longitudinal direction and connects the vertices p1 and p2 of two continuous troughs in the repetition of the crests and troughs that constitute the corrugated shape of the end. The ratio of the distance a and the shortest distance b connecting the straight line and the apex q of the peak located between the two continuous valleys satisfies the relationship b / a ≦ 2.0. It has been found that the wavy shape does not remain at the end after molding, and the occurrence of defective sealing can be effectively suppressed. The present invention has been completed by further studies based on these findings.

That is, this invention provides the invention of the aspect hung up below.
Item 1. A battery packaging material in which at least a base material layer, a metal layer, and a sealant layer are laminated in order,
The metal layer has a thickness of 30 μm or less;
The end in the width direction of the battery packaging material has a corrugated shape that undulates along the longitudinal direction,
In the repetition of the crest and trough constituting the corrugated shape of the end, it is located between the linear distance a connecting the vertices p1 and p2 of the two continuous troughs and the two continuous troughs. The battery packaging material in which the ratio of the apex q of the crest to the shortest distance b connecting the straight line satisfies the relationship of b / a ≦ 2.0.
Item 2. A loop of the battery packaging material having a width of 15 mm and a length of 250 mm and forming a loop with the base material layer of the battery packaging material as an outer side, and being measured under measurement conditions of a circumference of the loop of 90 mm and an indentation distance of 15 mm Item 6. The battery packaging material according to Item 1, wherein the stiffness value is 12.5 g / 15 mm or less.
Item 3. Item 3. The battery packaging material according to Item 1 or 2, wherein the linear distance a is in the range of 0.1 to 200.0 mm.
Item 4. Item 4. The battery packaging material according to any one of Items 1 to 3, wherein the shortest distance b is in a range of 0.1 to 10.0 mm.
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 an adhesive layer is laminated between the base material layer and the metal layer.
Item 7. Item 7. 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 6.

  According to the battery packaging material of the present invention, the corrugated shape formed at the end of the battery packaging material satisfies the above-mentioned specific conditions even though the thickness of the metal layer is very thin, 30 μm or less. Thereby, after shaping | molding, the corrugated shape of the said edge part does not remain | survive, but generation | occurrence | production of the sealing defect of the battery packaging material which can suppress generation | occurrence | production of a sealing defect effectively can be suppressed.

It is a schematic diagram showing that the wave shape is formed in the edge part of the width direction x of the battery packaging material of this invention, and represents the mode that it was unwound from the winding body. It is an enlarged view of the area | region of II of FIG. (A) has shown the case where the magnitude | size of two continuous trough parts A1 and A2 is the same, (B) has shown the case where trough part A2 is smaller than trough part A1. It is a schematic diagram for demonstrating the aspect of shaping | molding of the battery packaging material of this invention. It is typical sectional drawing which shows the laminated structure of the packaging material for batteries of this invention.

  The battery packaging material of the present invention is a battery packaging material in which at least a base material layer, a metal layer, and a sealant layer are sequentially laminated, and the thickness of the metal layer is 30 μm or less, and the battery packaging material The end in the width direction x has a corrugated shape that undulates along the longitudinal direction, and two troughs that are continuous in the repetition of the crest and trough that constitute the corrugated shape of the end. The ratio of the straight line distance a connecting the vertices p1 and p2 to the shortest distance b connecting the peak q of the peak located between the two continuous valleys and the straight line is b / a ≦ 2. It is characterized by satisfying the relationship of 0. 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. 4, the battery packaging material 10 of the present invention 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 10 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 seal the battery element, thereby sealing the battery element.

  For example, as shown in FIG. 4, the battery packaging material 10 of the present invention is provided with an adhesive layer 2 between the base material layer 1 and the metal layer 3 as necessary for the purpose of enhancing the adhesion. It may be. In addition, an adhesive layer (not shown) may be provided between the metal layer 3 and the sealant layer 4 as necessary for the purpose of enhancing these adhesive properties.

2. Shape of Battery Packaging Material As shown in FIGS. 1 and 2, the battery packaging material 10 of the present invention has a corrugated shape in which the end portion in the width direction x of the battery packaging material is undulated along the longitudinal direction y. Have. The corrugated shape in the battery packaging material 10 is usually generated at an end portion formed by cutting the battery packaging material with a slitter or the like. Therefore, in the battery packaging material 10, the wavy shape may exist only at one end portion or may exist at both end portions depending on whether or not the end portion is formed by cutting. 2 is an enlarged view of the region II in FIG. 1. FIG. 2A shows a case where two continuous valleys A1 and A2 have the same size, and FIG. The case where trough part A2 is smaller than part A1 is shown.

  As shown in FIG. 3, the battery packaging material is molded so as to protrude from the sealant layer side to the base material layer side, and then the sealant layer is heat-sealed, so that the battery element becomes the battery packaging material. Enclosed. The molding is performed, for example, by using a straight mold including a substantially rectangular male mold and a female mold having a clearance with the male mold on the female mold so that the sealant layer 4 is positioned on the male mold side. This can be done by placing the packaging material and pressing the battery packaging material at a predetermined pressure (surface pressure). By such molding, when the battery packaging material 10 of the present invention is viewed in plan from the base material layer 1 side, the battery packaging material 10 is formed with a portion 10a protruding in a substantially rectangular shape. Moreover, the substantially rectangular parallelepiped space in which a battery element is accommodated in the sealant layer 4 side is formed by the shaping | molding in the packaging material 10 for batteries of this invention by shaping | molding.

  In addition, the space which accommodates a battery element prepares the two packaging materials 10 for batteries of this invention, and heat-seals the sealant layer 4 in the state where the sealant layers 4 face each other. An electronic element may be accommodated in the remaining space. Further, by preparing the battery packaging material 10 of the present invention and the sheet-like laminate as described above, the sealant layer 4 is heat-sealed in a state where the sealant layers 4 face each other, so that one space is obtained. An electronic element may be accommodated in the. The molding depth of the battery packaging material is preferably 3.0 mm or more, more preferably about 5.0 to 10.0 mm, and still more preferably about 5.0 to 8.0 mm.

  In the present invention, as shown in the enlarged view of FIG. 2, two continuous valleys A1 and A2 (that is, one peak) in the repetition of the peaks and valleys constituting the undulating shape of the end. Between two vertices p1 and p2 formed between the two valleys) and the vertex q of the peak B located between the two continuous valleys A1 and A2 and the straight line. The ratio with the shortest distance b satisfies the relationship b / a ≦ 2.0. In the present invention, the relation of b / a ≦ 2.0 is satisfied at an arbitrary portion of the corrugated shape. In the battery packaging material of the present invention, the above relationship of the wave shape before molding is b / a> 0.01.

  When a wavy shape satisfying b / a> 2.0 is present at the end of the battery packaging material, the wavy shape remains even after molding, and a sealing failure of the battery packaging material is likely to occur. In contrast, in the present invention, the wavy shape at the end of the battery packaging material satisfies the relationship of b / a ≦ 2.0, so that the wavy shape remains at the end after molding. The occurrence of a seal failure can be effectively suppressed. In the present invention, in the evaluation of whether or not the wavy shape after molding remains, at the end portion after molding by the method of Examples described later, if b / a ≦ 0.01, It can be evaluated that the wavy shape does not remain.

  From the viewpoint of effectively suppressing the remaining wavy shape at the end after molding, the relationship between the linear distance a and the shortest distance b is preferably b / a ≦ 1.0, more preferably b. /A≦0.1.

  In the battery packaging material of the present invention, the linear distance a is preferably about 0.1 to 200 mm, more preferably about 1.0 to 200 mm, and still more preferably about 50 to 200 mm.

  In the battery packaging material of the present invention, the shortest distance b is preferably about 0.1 to 10.0 mm, more preferably about 0.1 to 2.0 mm, and still more preferably 0.1 to 1. About 0.0 mm.

  The linear distance a and the shortest distance b are values measured by using a digital caliper after leaving the battery packaging material on a flat surface with the sealant layer 4 facing downward.

  In the battery packaging material 10 of the present invention, the method for adjusting the corrugated shape of the end of the battery packaging material to have the above specific relationship is not particularly limited. For example, the battery packaging material using a slitter is used. When the material is cut in the length direction y to form an end portion having a corrugated shape, a method of appropriately setting cutting conditions such as adjusting the distance between the clearance between the upper blade and the lower blade used for cutting may be mentioned. A more specific method is as described in detail in the item of the manufacturing method described later.

  As described above, when the thickness of the metal layer 3 is as thin as 30 μm or less, the so-called “stiffness” as the battery packaging material is also reduced, and there is a problem that the wavy shape tends to remain at the end portion after molding. Such stiffness can be evaluated by a loop stiffness value. Specifically, the strength of the stiffness can be evaluated by producing a loop from the battery packaging material and crushing the diameter direction of the loop. In the battery packaging material of the present invention, a loop is formed with the base material layer of the battery packaging material having a width of 15 mm and a length of 250 mm on the outside, and the measurement is performed under the measurement conditions of a circumference of the loop of 90 mm and an indentation distance of 15 mm. Even when the loop stiffness value of the battery packaging material is 12.5 g / 15 mm or less, the corrugated shape formed at the end of the battery packaging material satisfies the specific condition. Thus, the remaining wavy shape at the end after molding can be effectively suppressed. To measure the loop stiffness value, a loop steffin tester manufactured by Toyo Seiki Co., Ltd. can be used.

  The total thickness of the battery packaging material of the present invention is not particularly limited. For example, when the thickness is 100 μm or less, and further about 80 to 50 μm, in the conventional battery packaging material, even after molding, However, in the present invention, by satisfying the relationship of b / a ≦ 2.0, the remaining wavy shape at the end after molding is effectively suppressed. Yes.

3. Composition of each layer forming base material for battery [base material layer 1]
In the battery packaging material 10 of the present invention, the base material layer 1 is a layer located in the outermost layer. The material for forming the base material layer 1 is not particularly limited as long as it has insulating properties. Examples of the material for forming the base material layer 1 include polyester, polyamide, epoxy resin, acrylic resin, fluorine resin, polyurethane, silicon resin, phenol resin, polyetherimide, polyimide, and a mixture or copolymer thereof. Can be mentioned.

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

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

  The base material layer 1 may be formed of a uniaxially or biaxially stretched resin film, or may be formed of an unstretched resin film. Among them, a uniaxially or biaxially stretched resin film, in particular, a biaxially stretched resin film has improved heat resistance by orientation crystallization, and thus is suitably used as the base material layer 1. Moreover, the base material layer 1 may be formed by coating the above-mentioned raw material on the metal layer 3.

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

  The base material layer 1 can also be laminated with at least one of resin films and coatings of different materials in order to improve pinhole resistance and insulation when used as a battery package. Specific examples include a multilayer structure in which a polyester film and a nylon film are laminated, and a multilayer structure in which a biaxially stretched polyester and a biaxially stretched nylon are laminated. When making the base material layer 1 into a multilayer structure, each resin film may be adhere | attached through an adhesive agent, and may be laminated | stacked directly without an adhesive agent. In the case of bonding without using an adhesive, for example, a method of bonding in a hot melt state such as a co-extrusion method, a sand lamination method, or a thermal laminating method can be mentioned. Moreover, when making it adhere | attach through an adhesive agent, the adhesive agent to be used may be a two-component curable adhesive, or a one-component curable adhesive. Further, the bonding mechanism of the adhesive is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a heat melting type, a hot pressure type, an electron beam curing type such as UV and EB, and the like. As an adhesive component, polyester resin, polyether resin, polyurethane resin, epoxy resin, phenol resin resin, polyamide resin, polyolefin resin, polyvinyl acetate resin, cellulose resin, (meth) acrylic resin Resins, polyimide resins, amino resins, rubbers, and silicon resins can be used.

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

[Adhesive layer 2]
In the battery packaging material 10 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.

  About the thickness of the contact bonding layer 2, about 1-10 micrometers is mentioned, for example, Preferably about 2-5 micrometers is mentioned.

[Metal layer 3]
In the battery packaging material 10 of the present invention, 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 10. It is.

  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 occurrence of pinholes in the metal layer 3, for example, it is more preferable to form with a soft aluminum foil such as annealed aluminum (JIS A8021P-O, JIS A8079P-O).

  In the present invention, the thickness of the metal layer 3 is 30 μm or less. As described above, when the thickness of the metal layer is reduced to 30 μm or less, the so-called “stiffness” of the battery packaging material is reduced, and when the laminated film is cut in the unwinding direction (length direction) as described above, The undulating shape in which the end portion of the laminated film undulates along the length direction is likely to occur. On the other hand, in the battery packaging material of the present invention, the corrugated shape formed at the end of the battery packaging material satisfies the above-mentioned specific condition, so that the corrugation of the end after molding is achieved. It is possible to effectively suppress the occurrence of poor sealing of the battery packaging material that does not remain in shape and can effectively suppress the occurrence of poor sealing.

  The thickness of the metal layer 3 is not particularly limited as long as it is 30 μm or less. However, the wavy shape of the end portion does not remain after molding while the total thickness of the battery packaging material is further reduced, resulting in poor sealing. From the viewpoint of effectively suppressing the occurrence of defective sealing of the battery packaging material that can effectively suppress the generation, about 15 to 25 μm is more preferable.

  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 a chromic acid compound such as chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium biphosphate, chromic acetyl acetate, chromium chloride, potassium chromium sulfate, 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 the aminated phenol polymer, the repeating units represented by the following general formulas (1) to (4) may be included singly or in any combination of two or more. Also good.

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 0C to about 200C. 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 10 of the present invention, the sealant layer 4 corresponds to the innermost layer, and the sealant layers are heat-welded to each other when the battery is assembled to seal the battery element.

  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.

  The thickness of the sealant layer 4 can be selected as appropriate, and is about 10 to 100 μm, preferably about 15 to 50 μm.

[Adhesive layer]
In the battery packaging material 10 of the present invention, the adhesive layer is a layer provided between the metal layer 3 and the sealant layer 4 as necessary in order to firmly bond the metal layer 3 and the sealant layer 4.

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

  About the thickness of an contact bonding layer, 2-50 micrometers, for example, Preferably 20-30 micrometers is mentioned.

4). Method for Producing Battery Packaging Material Regarding the method for producing the battery packaging material 10 of the present invention, after obtaining a laminate in which layers of a predetermined composition are laminated, the battery packaging material 10 is cut in the length direction y. As long as the corrugated shape of the end surface formed in this way satisfies the above-mentioned conditions, it is not particularly limited. 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. . When an adhesive layer is provided between the metal layer 3 and the sealant layer 4, for example, (1) a method of laminating the adhesive layer and the sealant layer 4 on the metal layer 3 of the laminate A by coextrusion. (Co-extrusion lamination method), (2) Separately, a laminate in which an adhesive layer and a sealant layer 4 are laminated, and this is laminated on the metal layer 3 of the laminate A by a thermal lamination method, (3) Lamination An adhesive for forming an adhesive layer is laminated on the metal layer 3 of the body A by an extrusion method, a solution-coated high temperature drying or baking method, and a sealant previously formed into a sheet on the adhesive layer A method of laminating the layer 4 by a thermal lamination method; (4) while pouring a molten adhesive layer between the metal layer 3 of the laminate A and the sealant layer 4 previously formed into a sheet shape, Laminated body A The method for bonding the sealant layer 4 (sand lamination method) and the like.

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

  By cutting the laminate obtained above in the length direction y using a slitter or the like and adjusting the length in the width direction x to a desired length, the battery packaging material of the present invention is obtained. Can do. Specifically, the laminate obtained above is wound around a cylindrical core tube or the like to obtain a wound body. Next, the laminated body is unwound from the obtained wound body, and the laminated body is cut in the longitudinal direction y using a shear-cut type slitter having an upper blade and a lower blade, thereby obtaining a desired width direction. A battery packaging material adjusted to the length x is obtained. At this time, the end portion formed by cutting has a undulating shape along the longitudinal direction y. For example, when forming an end portion having a corrugated shape by cutting the battery packaging material in the length direction y using a slitter, the cutting conditions such as adjusting the clearance distance between the upper blade and the lower blade used for cutting By setting appropriately, the corrugated shape of the end of the battery packaging material in the present invention can be adjusted to the above specific relationship. Specifically, the clearance distance between the upper blade and the lower blade is particularly preferably 2 mm or less. Further, the distance that the upper blade bites into the lower blade and overlaps is particularly preferably 1 mm or less. Furthermore, the cutting edge degree of the upper blade is particularly preferably 65 ° C. or less.

  In the battery packaging material 10 of the present invention, each layer constituting the laminate is used to improve or stabilize film-forming properties, lamination processing, suitability for secondary processing (pouching, embossing), etc., as necessary. In addition, surface activation treatment such as corona treatment, blast treatment, oxidation treatment, ozone treatment may be performed.

5). Application of Battery Packaging Material The battery packaging material 10 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, with the battery packaging material 10 of the present invention, with metal terminals connected to each of the positive electrode and the negative electrode protruding outward, The battery packaging material 10 is used by covering the periphery of the battery element so that a flange portion (region where the sealant layers are in contact with each other) can be formed and heat-sealing the sealant layers 4 of the flange portion together. Batteries are provided. In addition, when accommodating a battery element using the battery packaging material 10 of the present invention, it is used so that the sealant layer 4 of the battery packaging material 10 of the present invention is on the inner side (surface in contact with the battery element).

  As described above, two battery packaging materials 10 of the present invention are prepared, and the sealant layer 4 is heat-sealed in a state where the sealant layers 4 face each other. An element may be accommodated. Further, by preparing the battery packaging material 10 of the present invention and the sheet-like laminate as described above, the sealant layer 4 is heat-sealed in a state where the sealant layers 4 face each other, so that one space is obtained. An electronic element may be accommodated in the.

  The battery packaging material 10 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 the secondary battery to which the battery packaging material 10 of the present invention is applied is not particularly limited, and for example, a lithium ion battery, a lithium ion polymer battery, a lead live battery, a nickel / hydrogen live battery, a nickel / cadmium livestock. Examples include batteries, nickel / iron livestock batteries, nickel / zinc livestock batteries, silver oxide / zinc livestock batteries, metal-air batteries, multivalent cation batteries, capacitors, capacitors, and the like. Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries can be cited as suitable applications of the battery packaging material 10 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.

<Manufacture of battery packaging materials>
A base material layer 1 / adhesive layer 2 / metal layer 3 / sealant is obtained by laminating a sealant layer 4 by a thermal laminating method on a laminate in which base material layer 1 / adhesive layer 2 / metal layer 3 are laminated in order. A battery packaging material 10 comprising a laminate in which the layers 4 were sequentially laminated was produced. Specific production conditions for the battery packaging material are as follows.

In Example 1-7 and Comparative Example 1-5, the base material layer 1 and the metal layer 3 used the resin film and aluminum foil (aluminum alloy) described in Table 1, respectively. The thickness of the base material layer 1 is 12 μm, and the thicknesses of the PET layer / nylon layer are 12 μm and 15 μm, respectively. The thickness of the aluminum foil is as shown in Table 1, and the aluminum foil is A8021 made by Toyo Aluminum Co., Ltd. The aluminum foil was coated with 10 mg / m ² (dry weight) of a treatment solution consisting of a phenol resin, a chromium fluoride compound (trivalent), and phosphoric acid on both sides of the metal layer by a roll coating method. Chemical conversion treatment was performed by baking for 20 seconds under conditions of 180 ° C. or higher.

  First, the laminated body by which the base material layer 1 / adhesion layer 2 / metal layer 3 was laminated | stacked in order was produced. Specifically, an adhesive layer 2 made of a polyester main agent and an isocyanic curing agent two-component urethane adhesive is formed on one surface of the base layer 1 so as to have a thickness of 3 μm. A laminate was prepared by laminating the surface and pressure and heating to laminate the base layer 1 / adhesive layer 2 / metal layer 3 in order.

  Separately, a sealant layer 4 made of a two-layer coextruded film having the configuration shown in Table 1 was prepared. Each sealant layer 4 was formed into a two-layer coextruded film by coextruding a resin layer constituting the metal layer side and a resin layer constituting the innermost layer side. In Table 1, the thickness of acid-modified PP (unsaturated carboxylic acid graft-modified random polypropylene graft-modified with unsaturated carboxylic acid) is 14 μm, the thickness of PP (polypropylene (random copolymer)) is 10 μm, and acid-modified PE (unsaturated). The thickness of unsaturated carboxylic acid graft-modified random polyethylene graft-modified with saturated carboxylic acid is 14 μm, and the thickness of PE (polyethylene (random copolymer)) is 10 μm.

  Next, the resin layer constituting the metal layer side of the two-layer coextruded film prepared above is in contact with the metal layer of the laminate composed of the base material layer 1 / adhesive layer 2 / metal layer 3 prepared above. In addition, by performing thermal lamination by heating the metal layer 3 to 120 ° C., a laminate in which the base material layer 1 / adhesive layer 2 / metal layer 3 / sealant layer 4 were sequentially laminated was obtained. After cooling the obtained laminate once, it is heated to 180 ° C. and kept at that temperature for 1 minute to perform a heat treatment to form a laminate having a length of 200 m and a width of 400 mm. The core tube was wound up.

  Next, the laminated body is unwound from the obtained wound body, and the laminated body is cut using a shear cut type slitter having an upper blade and a lower blade so as to be equally divided into three in the width direction x. The wound body of the battery packaging material of Example 1-7 and Comparative Example 1-5 in which the length in the width direction x was 1/3 was obtained. The cutting conditions of Example 1-7 are such that the clearance distance between the upper blade and the lower blade is set within 2 mm, the distance that the upper blade bites into the lower blade is set within 1 mm, and the upper blade is By using a blade having a blade angle of 60 °, the wavy shape was adjusted. Moreover, the cutting conditions of Comparative Example 1-5 are set such that the clearance distance between the upper blade and the lower blade is set to 2 mm or more, the distance at which the upper blade bites into the lower blade is set to 1 mm or more, and the upper blade is A blade with an edge angle of 85 ° was used.

<Measurement of b / a value>
Out of the wound bodies obtained in Example 1-7 and Comparative Example 1-5, the battery packaging material is unwound from the wound body in which both end portions are formed by cutting, and the battery packaging material 10 is widened. Cut in the direction x, a strip of length 120 × width 80 mm was produced. It is assumed that one side of the strip piece always includes an end portion by slit cutting. The obtained strip piece was allowed to stand on a flat surface with the sealant layer 4 facing downward, the linear distance a and the shortest distance b were measured using a digital caliper, and the b / a value was calculated. The results are shown in Table 1.

<Appearance evaluation after moldability>
Ten strips each including an end portion obtained by cutting a slit whose b / a value was measured as described above were used as samples, and obtained from the wound bodies of Example 1-7 and Comparative Example 1-5. Each sample was evaluated for appearance after molding. Using a straight mold composed of a 50 × 90 mm rectangular male mold and a female mold with a clearance of 0.5 mm between the male mold and the sample on the female mold so that the sealant layer side of the sample is located on the male mold side Was pressed with a presser pressure (surface pressure) of 0.4 MPa, and cold-formed (drawn one step) at a depth of 5.0 mm. After molding, the case where the wavy shape did not remain at the end portions of all 10 samples was evaluated as good (◯), and the case where the wavy shape remained was evaluated as poor (x). Whether the wavy shape remains after molding is determined by measuring the b / a value in the same manner as in the above <b / a value measurement> for the sample after molding, and b / a <0.01. When there was, it was evaluated that the wavy shape did not remain, and when b / a ≧ 0.01, it was determined that the wavy shape remained. The results are shown in Table 1.

  The battery packaging material was manufactured in the same manner as in the above example except that the thickness of the metal layer was 40 μm, and slitting was performed under the same cutting conditions as in the above example. There wasn't.

<Sealability evaluation>
An electrolytic solution in which 1000 ppm of pure water was added to the molded space using the sample after cold forming used in the above-described appearance evaluation after formability and a sheet (unformed) having the same layer configuration as the sample. 3 mg of ethylene carbonate (diethyl carbonate, dimethyl carbonate (1: 1: 1)) made to be 1M LiPF ₆ was sealed, and the sealant at the periphery of the sample after cold forming and the sheet having the same layer structure as the sample The four sides of the molded part were sealed so that the surfaces were aligned. Using a sealing machine manufactured by Fuji Impulse Co., Ltd., sealing was performed at 190 ° C. for 3 seconds with a 10 mm seal width head. It was put into an 85 ° C. thermostat, and after 3 days, the electrolyte solution was taken out and the seal part was cut to 15 mm, and a tensile test (300 mm / min) was performed with an autograph manufactured by Shimadzu Corporation to measure the seal strength. . A seal strength of 30 N / 15 mm or more was evaluated as “◯”, and a seal strength of 30 N / 15 mm or less was evaluated as “X”. The results are shown in Table 1.

<Measurement of loop stiffness value>
Among the wound bodies obtained in Example 1-7 and Comparative Example 1-5, the battery packaging material was unwound from the wound body having both ends formed by cutting, and the length direction was 250 mm and the width direction was 15 mm. A test piece (no corrugated shape at both ends) was prepared. Next, using a loop stiffness tester manufactured by Toyo Seiki Co., Ltd., forming a loop with the base material layer of the battery packaging material facing outward, the loop stiffness value is measured under the measurement conditions of the circumference of the loop of 90 mm and the indentation distance of 15 mm. It was measured. The results are shown in Table 1. It can be said that the larger the loop stiffness value, the greater the so-called “koshi” of the battery packaging material.

  In Table 1, PET means polyethylene terephthalate, PBT means polybutylene terephthalate, PP means polypropylene, and PE means polyethylene.

DESCRIPTION OF SYMBOLS 1 Base material layer 2 Adhesive layer 3 Metal layer 4 Sealant layer 5 Adhesive layer 10 Battery packaging material A1, A2 Valley part B Peak part p1, p2 Peak of peak q Peak of peak part a Peak of two continuous valleys Straight line distance b connecting p1 and p2 Shortest distance x connecting the straight line with the apex q of the crest located between two continuous valleys Width direction y Length direction (longitudinal direction)
z Thickness direction

Claims (7)

A battery packaging material in which at least a base material layer, a metal layer, and a sealant layer are laminated in order,
The metal layer has a thickness of 30 μm or less;
Edge in the width direction of the battery packaging materials has a wavy corrugation shape along the longitudinal direction,
In the repetition of the crest and trough constituting the corrugated shape of the end, it is located between the linear distance a connecting the vertices p1 and p2 of the two continuous troughs and the two continuous troughs. The ratio of the apex q of the crest to the shortest distance b connecting the straight line connecting the apexes p1 and p2 of the two continuous valleys is b / a ≦ 2.0 and b ≦ 2.0 mm Satisfying battery packaging materials.   A loop of the battery packaging material having a width of 15 mm and a length of 250 mm and forming a loop with the base material layer of the battery packaging material as an outer side, and being measured under measurement conditions of a circumference of the loop of 90 mm and an indentation distance of 15 mm The battery packaging material according to claim 1, wherein the stiffness value is 12.5 g / 15 mm or less.   The battery packaging material according to claim 1 or 2, wherein the linear distance a is in a range of 0.1 to 200.0 mm. The battery packaging material according to any one of claims 1 to 3, wherein the shortest distance b is in a range of 0.1 to 1.0 mm.   The battery packaging material according to any one of claims 1 to 4, wherein the metal layer is formed of an aluminum foil.   The battery packaging material according to claim 1, wherein an adhesive layer is laminated between the base material layer and the metal layer.   The battery by which the battery element provided with the positive electrode, the negative electrode, and the electrolyte is accommodated in the packaging material for batteries in any one of Claims 1-6.