JP2006159555A - Laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminate for a lithium cell of a type constituted so as to grasp the metal terminals connected to the respective positive and negative electrodes of a lithium cell main body in an outwardly protruded state to thermally bond and hermetically seal them, capable of being manufactured with good productivity and reduced in moisture permeation quantity from its end surface when used in the cell. <P>SOLUTION: In the laminate constituted by successively laminating a base material layer 2, an aluminum foil 3, a chemical forming treatment layer 4, a fluorine type primer layer 5, a fluorine type adhesive layer 6 and a thermally adhesive resin layer 7, the fluorine type primer layer 5 and the fluorine type adhesive layer 6 are formed of a composition prepared by compounding a hydroxy group-containing fluorine-containing copolymer and a curing agent reacted with this fluorine-containing copolymer and the fluorine type primer layer 5 is a layer with a coating amount of 1.0 g/m<SP>2</SP>or below formed by applying the composition to the surface of the chemical forming treatment layer to bake the same. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a laminate for packaging a secondary battery, in particular, a lithium battery main body having an electrolyte (liquid or solid electrolyte).

  A lithium battery is also called a lithium secondary battery, which is a battery made of a solid polymer, a gel polymer, a liquid, etc. as an electrolyte, and that generates electricity by the movement of lithium ions. It includes what consists of. The composition of the lithium secondary battery is as follows: positive electrode current collector (aluminum, nickel) / positive electrode active material layer (metal positive electrode material such as metal oxide, carbon black, metal sulfide, electrolyte, polyacrylonitrile) / electrolyte (propylene carbonate) , Carbonate electrolytes such as ethylene carbonate, dimethyl carbonate, ethylene methyl carbonate, inorganic solid electrolytes composed of lithium salts, gel electrolytes) / negative electrode active material layers (lithium metals, alloys, carbon, electrolytes, polymers such as polyacrylonitrile) A negative electrode material) / a negative electrode current collector (copper, nickel, stainless steel), and a lithium battery main body and an exterior housing them. Lithium secondary batteries are widely used in electronic devices and electronic components, particularly mobile phones, notebook computers, video cameras and the like because of their high volumetric efficiency and weight efficiency.

  The exterior of the lithium battery is roughly classified into a cylindrical or cuboid metal can sealed by metal bonding and a flexible laminated body thermally bonded and sealed. Easy to take out, easy to seal, or flexible so that it can be shaped to fit the appropriate space of the electronic device or electronic component, and the shape of the electronic device or electronic component itself can be designed to some extent freely Therefore, a laminate in which metal foils such as a plastic film and aluminum are laminated has been used for the reason that it is easy to reduce the size and weight.

  The laminated body has physical properties required for a lithium battery, that is, moisture resistance, sealing performance, puncture resistance, insulation, heat / cold resistance, electrolyte resistance (electrolytic solution resistance), corrosion resistance ( Since the deterioration of the electrolyte and the resistance to hydrofluoric acid generated by hydrolysis are required as indispensable, the laminate has a base material layer for preventing puncture resistance and external energization, moisture-proof A barrier layer made of a metal foil such as aluminum for ensuring the safety, and an inner layer excellent in adhesiveness with a metal terminal connected to each of the positive electrode and the negative electrode of the lithium battery main body, or sealed, or sealed In general, a laminate composed of an inner layer having thermal adhesiveness for securing the property is used.

  As a form of the lithium battery, the above-described laminate is formed into a bag shape as shown in FIG. 2 (a) at the peripheral heat-bonding portion [FIG. 2 (a) is a pillow type packaging bag, but three-way It may be a packaging bag of a type, a four-way type, etc.), and although not shown, the metal terminal connected to each of the positive electrode and the negative electrode of the lithium battery main body is stored in a state protruding outward, and the opening is formed. The bag type shown in FIG. 2 (b) which is thermally bonded and sealed, or the above-described laminate is press-molded as shown in FIG. 3 (a) to form a recess, which is not shown in the figure. The metal terminal connected to each of the positive electrode and the negative electrode of the lithium battery main body is stored in a state of protruding outward, and although not illustrated, the concave portion is covered with the sheet-like laminate prepared separately, and four peripheral edges are provided. Heat seal and seal There is a molding type shown in FIG. 3 (b). In addition, although not shown in the figure, the four peripheral edges are thermally bonded using a press-molded one as shown in FIG. 3 (a) instead of the sheet-like packaging material covering the recess. There is also a molding type in which recesses are formed on both sides sealed. 2 and 3 are forms of the lithium battery of the present invention. 2 and 3, reference numeral 1 indicates a packaging material, reference numeral D indicates a lithium battery, reference numeral S indicates a peripheral thermal bonding portion, and T indicates a metal terminal.

  In any of the above-described lithium batteries, when the lithium battery main body is sealed with the laminate, the metal terminals connected to the positive electrode and the negative electrode of the lithium battery main body are protruded to the outside and the metal terminals are used in the laminate. It is necessary to seal by thermal bonding in a state of sandwiching. For this purpose, the inner layer of the laminate is sealed by heat bonding using a heat-adhesive resin having good adhesion to the metal, for example, an acid-modified olefin resin graft-modified with an unsaturated carboxylic acid, or The above-mentioned acid modification that uses a general olefin resin (linear or branched olefin resin composed of carbon and hydrogen) that has poor adhesion to metal for the inner layer and has good adhesion to the metal A method is generally employed in which an adhesive film for sealing a metal terminal portion made of an olefin resin is interposed between the metal terminal and the inner layer to be thermally bonded and sealed.

Whichever sealing method is employed, the barrier layer made of a metal foil such as aluminum of the laminate and the inner layer inside this from the meaning of minimizing the amount of moisture permeation from the end face when used as a battery, A laminating method by a thermal lamination method (see, for example, Patent Document 2) is employed without adopting a laminating method by a dry lamination method (for example, see, for example, Patent Document 1) performed using a known dry lamination adhesive such as polyester. Usually adopted. This is because when moisture permeates, it reacts with the electrolyte (lithium hexafluorophosphate solution) to generate hydrofluoric acid, which reduces the adhesion between the barrier layer made of a metal foil such as aluminum and the inner layer. This is because peeling occurs and the battery life is shortened. However, the thermal lamination method has a problem that the productivity (processing) is inferior to that of the dry lamination method, so that the laminated body is high in cost.
Japanese Patent Publication No. 7-19589 Japanese Examined Patent Publication No. 4-58146

  Accordingly, the present invention is a laminate for a lithium battery of a type in which a metal terminal connected to each of a positive electrode and a negative electrode of a lithium battery main body is sandwiched in a protruding state and thermally bonded and sealed. It can be manufactured well, and the amount of moisture permeation from the end face when it is made into a battery can be reduced to a level comparable to the laminate manufactured by the thermal lamination method. Another object of the present invention is to provide a laminate excellent in various physical properties such as heat resistance / cold resistance, electrolytic solution resistance, and corrosion resistance.

  In order to achieve the above object, the present inventor has at least a base material layer, an aluminum foil, a chemical conversion treatment layer, a fluorine primer layer, a fluorine adhesive layer, and a heat adhesive resin layer. In the laminated body laminated in order, the fluorine-based primer layer and the fluorine-based adhesive layer are formed of a composition containing a fluorine-containing copolymer containing a hydroxyl group and a curing agent that reacts with the fluorine-containing copolymer, And the said fluorine-type primer layer is a layer formed by apply | coating and baking the said composition on the said chemical conversion treatment layer surface.

  The present invention according to claim 2 is the laminate according to claim 1, wherein the curing agent of the fluorine-based primer layer is selected from the group consisting of blocked isocyanate, a polymer thereof, and a melamine curing agent. It is characterized by being. By comprising in this way, it can be set as the laminated body in which each interlayer by the side of a heat-adhesive resin layer from aluminum foil has the lamination strength stable with respect to electrolyte solution, and when it was set as the battery, the stable heat It can be set as the battery packaging body which has sealing strength.

  In the laminate of the present invention, since the fluorine-based primer layer is formed on the surface of the chemical conversion treatment layer by baking, the adhesive strength with the surface of the chemical conversion treatment layer can be increased, and the laminate is laminated on the fluorine-based primer layer. Since the adhesive strength with the fluorine-based adhesive layer is the same type of resin, it can be made strong, and a laminate having excellent physical properties in terms of electrolytic solution resistance and corrosion resistance can be obtained. In addition, since the fluorine-based primer layer and the fluorine-based adhesive layer have a small amount of moisture permeation, the amount of moisture permeation from the end face of the battery can be reduced. Furthermore, since the fluorine-based primer layer and the heat-adhesive resin layer are stacked by a dry lamination method using a fluorine-based adhesive, a laminate having excellent productivity can be obtained.

The above-described present invention will be described in detail below with reference to the drawings.
FIG. 1 is a diagram schematically showing a layer structure of an embodiment of a laminate according to the present invention. The laminate 1 includes a base layer 2, an aluminum foil 3, a chemical conversion treatment layer 4, a fluorine-based primer layer 5, A fluorine-based adhesive layer 6 and a heat-adhesive resin layer 7 are sequentially laminated.

  The base layer 2 is provided for the purpose of protecting the aluminum foil 3 from external force and improving the puncture resistance against puncture from the outside, and has been stretched in the biaxial direction from the viewpoint of excellent mechanical strength. A polyester film, a polyamide film, or a laminate thereof can be exemplified. Examples of the polyester film include films made of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polycarbonate and the like, and examples of the polyamide film include nylon 6, nylon 6,6, nylon 6, A film composed of 10 etc. can be mentioned. The thickness of the base material layer 2 is suitably 6 μm or more. The reason for this is that if the thickness is less than 6 μm, there may be pinholes in itself, and the protective effect of the aluminum foil 3 against external force is reduced, especially in the case of the molding type (see FIG. 3). This is because pinholes and breakage are likely to occur in the aluminum foil 3 and molding defects are likely to occur, and more preferably 12 μm or more. In addition, when the base material layer 2 is a single layer or multiple layers of the above-described film, when it is thicker than 25 μm, no significant effect is recognized in terms of protection of the aluminum foil 3 against external force, and volume and weight energy density. It is desirable not to use it from the viewpoint of cost effectiveness. In addition, the above-described polyester film and polyamide film may be subjected to easy adhesion treatment such as corona discharge treatment, ozone treatment, and plasma treatment on a necessary surface.

  The aluminum foil 3 is provided in order to prevent water vapor from entering inside the battery from the outside. Considering ensuring of water vapor barrier properties and suitability for processing, 20-100 μm The thickness of is suitable. If the thickness is less than 20 μm, the pinhole of the aluminum foil alone is a concern, and the risk of intrusion of water vapor increases. If the thickness is greater than 100 μm, a remarkable effect is recognized on the pinhole of the aluminum foil. Further, it is desirable not to further improve the water vapor barrier property, and conversely to reduce the volume and weight energy density and not to use from the viewpoint of cost effectiveness.

  In addition, the aluminum foil 3 contains 0.3 to 9.0% by weight, preferably 0.7 to 2.0% by weight of iron, and has excellent ductility as compared with the one not containing iron, and is resistant to bending. It is preferable to use an aluminum foil containing iron in the laminate 1 in the case of forming a molding type (see FIG. 3) in order to obtain a uniform molded product with little occurrence of pinholes and particularly uneven thickness during press molding. . If the iron content is less than 0.3% by weight, no effect is observed in prevention of pinholes and spreadability, and if the iron content exceeds 9.0% by weight, the flexibility as an aluminum foil is hindered. However, the moldability decreases.

  The aluminum foil 3 is manufactured by cold rolling, but its flexibility, waist strength and hardness change under annealing (so-called annealing treatment) conditions, but the aluminum foil used in the present invention is annealed. An aluminum foil that tends to be softer than the hard-treated product that has been annealed to some degree or completely is preferable. Moreover, the annealing conditions of the aluminum foil that determine flexibility, waist strength, and hardness can be appropriately determined depending on whether the laminate 1 is used as a bag type (see FIG. 2) or a molding type (see FIG. 3). It ’s good.

  The chemical conversion treatment layer 4 prevents the corrosion of the aluminum foil 3 due to hydrofluoric acid generated by hydrolysis of the electrolytic solution and the electrolytic solution, and the aluminum foil 3 caused by hydrofluoric acid generated by hydrolysis of the electrolytic solution and the electrolytic solution. Delamination between the chemical conversion treatment layer 4 is prevented, and further, the fluorine based primer layer 5 laminated on the chemical conversion treatment layer 4 is firmly adhered, and is generated by hydrolysis of the electrolytic solution or the electrolytic solution. It is provided to prevent delamination from this layer by hydrofluoric acid. Further, in the case of a molding type battery, it is provided in order to prevent delamination between the layers described above during press molding. The chemical conversion treatment layer 4 is formed by chromium chemical conversion treatment such as chromic acid chromate treatment, phosphoric acid chromate treatment, and coating type chromate treatment, or non-chromium (coating type) chemical conversion treatment such as zirconium, titanium, and zinc phosphate. Although formed on the surface of the aluminum foil 3, a coating type chemical conversion treatment is suitable because continuous treatment is possible and a water washing step is unnecessary and the processing cost can be reduced. The treatment solution may be treated with a conventionally known chromate treatment solution containing a hexavalent chromium compound, but is environmentally friendly and does not easily cause a decrease in the adhesive strength between the layers as time passes. Specifically, it is preferably formed using a treatment liquid containing an aminated phenol polymer, a trivalent chromium compound, and a phosphorus compound.

First, the aminated phenol polymer will be described. A well-known thing can be widely used as an aminated phenol polymer, for example, aminated phenol heavy which consists of a repeating unit represented by following formula (1), (2), (3), (4). Coalescence can be mentioned. X in the formula 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 represent a hydroxyl group, an alkyl group, or a hydroxyalkyl group, and may be the same group or different groups.

In the following 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, can be 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 can be mentioned. X in the following formulas (1) to (4) is preferably any one of a hydrogen atom, a hydroxyl group, and a hydroxyalkyl group.

Further, the aminated phenol polymer represented by the following formulas (1) and (3) is an aminated phenol containing about 80 mol% or less of repeating units, preferably about 25 to about 55 mol% of repeating units. It is a polymer. The number average molecular weight of the aminated phenol polymer is preferably about 500 to about 1 million, more preferably about 1000 to about 20,000. The aminated phenol polymer is produced by, for example, polycondensing a phenol compound or naphthol compound and formaldehyde to produce a polymer composed of repeating units represented by the following (1) to (3). It is produced by introducing a water-soluble functional group (—CH ₂ NR ₁ R ₂ ) using formaldehyde and an amine (R ₁ R ₂ NH). The aminated phenol polymer can be used singly or in combination of two or more.

  Next, the trivalent chromium compound will be described. As the trivalent chromium compound, known compounds can be widely used. For example, chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium biphosphate, chromic acetyl acetate, chromium chloride, sulfuric acid Potassium chromium etc. can be mentioned, Preferably they are chromium nitrate and chromium fluoride.

  Next, a phosphorus compound is demonstrated. As a phosphorus compound, a well-known thing can be used widely, For example, condensed phosphoric acids, such as phosphoric acid and polyphosphoric acid, these salts, etc. can be mentioned. Here, as said salt, alkali metal salts, such as ammonium salt, sodium salt, potassium salt, can be mentioned, for example.

And as said chemical conversion treatment layer 4 formed using the processing liquid containing an aminated phenol polymer, a trivalent chromium compound, and a phosphorus compound, about 1 to about 200 mg of aminated phenol polymers per 1 m ^2. It is appropriate that the trivalent chromium compound is contained in a proportion of about 0.5 to about 50 mg in terms of chromium, and the phosphorus compound is contained in a proportion of about 0.5 to about 50 mg in terms of phosphorus. Is preferably about 5.0 to 150 mg, the trivalent chromium compound is contained in a proportion of about 1.0 to about 40 mg in terms of chromium, and the phosphorus compound is contained in a proportion of about 1.0 to about 40 mg in terms of phosphorus. . In this case, the drying temperature is 150 to 250 ° C., preferably 170 to 250 ° C., and the heat treatment (baking treatment) is appropriate.

  Moreover, as a formation method of the said chemical conversion treatment layer 4, what is necessary is just to select the well-known coating methods, such as a bar coating method, a roll coating method, a gravure coating method, a dipping method, and to form the said processing liquid suitably. Moreover, before forming the said chemical conversion treatment layer 4, well-known degreasing processes, such as an alkali immersion method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, an acid activation method, are previously carried out on the aluminum foil 3 surface. It is preferable to perform the treatment by the method from the viewpoint that the function of the chemical conversion treatment layer 4 can be exhibited to the maximum and can be maintained for a long time.

Next, the fluorine-based primer layer 5 and the fluorine-based adhesive layer 6 will be described. The fluorine-based resin used for the fluorine-based primer layer 5 and the fluorine-based adhesive layer 6 is formed of a fluorine-containing copolymer containing a hydroxyl group and a curing agent that reacts with the fluorine-containing copolymer. Is a layer. The fluorine-containing copolymer containing a hydroxyl group is an organic solvent-soluble type having a crosslinking site in the molecule, and the crosslinking site is an alcoholic hydroxyl group (OH group) or the like. As such a fluorine-containing copolymer, for example, 1) a fluoroolefin monomer represented by the formula: CF ₂ = CFX [wherein X is a fluorine atom, a hydrogen atom or a trifluoromethyl group], 2) β-methyl substituted α-olefin monomer represented by the formula: CH ₂ = CR (CH ₃ ) [wherein R is an alkyl group having 1 to 8 carbon atoms], 3) Formula: CH ₂ = CHR ^{1 wherein} R ¹ is —OR ² or —CH ₂ OR ² (where R ² is an alkyl group having a hydroxyl group), and 4) crosslinkability. Mention may be made of fluorine-containing copolymers derived from other monomers which do not have a functional group and can be copolymerized with the monomers 1), 2) and 3).

  Examples of the fluoroolefin monomer include tetrafluoroethylene, trifluoroethylene, hexafluoropropylene, and the like. Examples of the β-methyl-substituted α-olefin monomer include isobutylene, 2-methyl-1-pentene, 2-methyl-1-hexene and the like. Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, 2-hydroxypropyl vinyl ether, 2-hydroxy-2-methylpropyl vinyl ether, 4-hydroxybutyl vinyl ether, and 5-hydroxypentyl. Examples include vinyl ether, 6-hydroxyhexyl vinyl ether, 2-hydroxyethyl allyl ether, and 4-hydroxybutyl allyl ether. Examples of other monomers that can be copolymerized with the fluoroolefin monomer, the β-methyl-substituted α-olefin monomer, and the hydroxyl group-containing monomer include vinyl acetate and vinyl propionate (isopropylene). ) Carboxylic acid vinyl esters such as vinyl butyrate, vinyl caproate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl xafluoropropionate, vinyl trifluoroacetate, dimethyl, diethyl, dipropyl, dibutyl of maleic acid or fumaric acid , Diesters of maleic acid or fumaric acid such as, ditrifluoromethyl, ditrifluoromethyl, and dihexafluoropropyl, alkyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, iso-butyl vinyl ether, tert-butyl vinyl ether, etc. In addition to cycloalkyl vinyl ethers such as kill vinyl ethers, cyclopentyl vinyl ethers and cyclohexyl vinyl ethers, vinyl ethers having aromatic groups such as benzyl vinyl ethers, or fluoroalkyl vinyl ethers such as perfluoroethyl vinyl ether and perfluoropropyl vinyl ether, croton Examples thereof include acid, vinyl acetic acid, maleic acid, and styrene.

  The fluorine-containing copolymer having a hydroxyl group can be obtained by copolymerizing the monomers 1) to 4) by a known method such as emulsion polymerization, solution polymerization or suspension polymerization. The fluorine-containing copolymer having a hydroxyl group has a number average molecular weight measured by GPC of 1,000 to 500,000, preferably 3000 to 100,000.

  As the curing agent, an organic polyisocyanate compound is suitable because it contains a hydroxyl group at the cross-linking site. For example, 2,4-tolylene diisocyanate, diphenylmethane-4,4′-diisocyanate, xylylene diisocyanate, isophorone. Diisocyanate (hereinafter referred to as IPDI), lysine methyl ester diisocyanate, methylcyclohexyl diisocyanate, trimethylhexamethylene diisocyanate, hexamethylene diisocyanate (hereinafter referred to as HDI), n-pentane-1,4-diisocyanate, and these Trimers, adducts and burettes thereof, or polymers having two or more isocyanate groups, and blocked isocyanates, or Methylated melamine, butylated melamine, melamine-based curing agents such as mixed alkylated melamine can be mentioned. In addition, the fluorine-containing copolymer containing the hydroxyl group and the curing agent are dissolved in a solvent in which one or more of acetates, ketones, ethers, aromatic hydrocarbons and the like are mixed, for example, When using a system hardening agent, it will be 0.1-5.0 equivalent with respect to 1 equivalent of hydroxyl groups (-OH group) in the said fluorine-containing copolymer, Preferably it will be 0.5-1.5 equivalent. In addition, when a melamine curing agent is used, it is 5 to 30 parts by weight, preferably 10 to 20 parts by weight with respect to 100 parts by weight of the fluorine-containing copolymer. It is suitable to mix them, and it may be formed by coating by a known coating method such as a roll coating method, a gravure coating method or a bar coating method.

By the way, the reason for providing the fluorine-based primer layer 5 is to provide the fluorine-based adhesive layer 6 and the chemical conversion treatment layer 4 through the fluorine-based primer layer 5, A composition containing a fluorine-containing copolymer containing a hydroxyl group and a curing agent that reacts with the fluorine-containing copolymer on the surface of the chemical conversion treatment layer 4 is applied to the surface of the chemical conversion treatment layer, preferably in the range of 150 to 250 ° C., preferably It is formed by baking at a temperature in the range of 180 to 250 ° C. The coating amount after baking is preferably as a thin film in consideration of baking time and moisture permeation from the end face when used as a battery. Practically, it is 1 g / m ² or less, preferably 100 to 500 mg / m ² . The fluorine-based primer layer 5 is formed by baking, and as the curing agent, blocked isocyanates that cure at the temperature during baking and polymers thereof or melamine-based curing agents are preferable.

Moreover, as the said fluorine-type adhesive bond layer 6, the hardening | curing agent which reacts with the hydroxyl group of a fluorine-containing copolymer by heating at 40-60 degreeC is preferable, for example, 2, 4- tolylene diisocyanate. , Diphenylmethane-4,4′-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, lysine methyl ester diisocyanate, methylcyclohexyl diisocyanate, trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, n-pentane-1,4-diisocyanate, and three of these Preferred are those having two or more isocyanate groups in the form of polymers, adducts or burettes thereof, or polymers thereof. The fluorine-based adhesive layer 6 is a film that forms a heat-adhesive resin layer 7 described later at the same time as applying and drying a composition containing a fluorine-containing copolymer and a curing agent on the surface of the fluorine-based primer layer 5. are those formed by laminating a well-known dry lamination method, the coating amount after drying 2.0~5.0g / m ^2, of preferably coated to a 3.0 g / m ² or more Is appropriate. The reason is that 2.0 g / m ² or more is necessary from the viewpoint of securing the laminate strength, and 5.0 g / m ² or less in consideration of moisture permeation from the end face and cost when the battery is manufactured.

  Next, the thermal adhesive resin layer 7 will be described. As the thermal adhesive resin layer 7, the metal terminal connected to each of the positive electrode and the negative electrode of the lithium battery main body is sandwiched in a state of projecting outward, and is thermally bonded to be sealed. The resin type differs depending on whether or not a metal terminal sealing adhesive film is interposed between the metal terminal and the metal terminal. When interposing an adhesive film for sealing metal terminals, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, ethylene-butene copolymers and other ethylene-based resins, homopolypropylene, ethylene- A film made of a simple substance or a mixture of propylene resins such as a propylene copolymer and an ethylene-propylene-butene copolymer may be appropriately selected and used, and when an adhesive film for sealing a metal terminal portion is not interposed. For example, a film made of an acid-modified olefin resin graft-modified with an unsaturated carboxylic acid may be used. The thickness of the heat-adhesive resin layer 7 is 20 to 80 μm, preferably 30 to 70 μm. If the thickness is less than 20 μm, there is a possibility that the heat seal strength as a battery cannot be sufficiently obtained. This is because moisture permeation from the end face is increased and the performance as a battery may be reduced.

  Although not shown, the lamination of the base material layer 2 and the aluminum foil 3 is well-known using, for example, a well-known dry lamination adhesive such as polyester, polyether or polyurethane. What is necessary is just to laminate | stack by the dry lamination method. Moreover, when using the said laminated body 1 for a shaping | molding type (refer FIG. 3), the chemical conversion treatment layer 4 demonstrated above is provided in the surface by which the said base material layer 2 of the said aluminum foil 3 is laminated | stacked. Is preferred. The reason for this is that delamination between the aluminum foil 3 and the outer layer 2 during press molding can be prevented. For the bag type (see FIG. 2), there is no need to provide it. It is. In the case where the laminate 1 is a molding type (see FIG. 3), the laminate 1 is prevented from partially adhering to the mold during press molding to prevent uneven thickness (thickness variation). For the purpose of obtaining a uniform press-molded product (for the purpose of improving the moldability at the time of press-molding), for example, the surface of the base material layer 2 such as hydrocarbons such as liquid paraffin, stearic acid, erucic acid Fatty acid amides such as fatty acids, stearylamide, erucic acid amides, metal soaps, natural waxes, silicones and other lubricants can be applied in a suitable solvent, such as gravure coating, roll coating, etc. In the case of forming a pattern or a pattern, the lubricant layer may be formed by a known coating method such as a gravure printing method.

  Next, the present invention will be described in detail with reference to experimental examples.

[Experimental Example 1]
Treated with a 25 μm thick biaxially stretched nylon film (hereinafter referred to as ON film) as a substrate layer and a chemical conversion treatment solution containing an aminated phenol polymer, a trivalent chromium compound, and a phosphorus compound in advance. After laminating one surface of an aluminum foil (40 μm thickness) having a chemical conversion treatment layer formed on both sides with a two-component curable polyurethane adhesive, the other surface of the aluminum foil is coated with a fluorine-based polyol ( Fluorine-containing resin solution in which IPDI is added to 1.1 equivalent to 1 equivalent of hydroxyl group (—OH group) of polyol to a fluorine-containing copolymer having a hydroxyl group, so that the solid content is 500 mg / m ^2. And an intermediate laminate having a fluorine-based primer layer formed by baking at a drying temperature of 180 ° C. The isocyanate-based curing agent is added to the fluorine-based polyol (fluorine-containing copolymer having a hydroxyl group) on the surface of the fluorine-based primer layer of the intermediate laminate, and 1.1 equivalent to 1 equivalent of the hydroxyl group (-OH group) of the polyol. An unstretched polypropylene film (hereinafter referred to as 30 μm thick) on the surface of the fluorine resin layer (fluorine adhesive layer) formed by applying and drying the fluorine resin solution added to the powder to 3.0 g / m ² after drying. , Referred to as a CPP film), and laminated (on film 25 μm / adhesive layer / chemical conversion layer / aluminum foil 40 μm / chemical conversion layer / fluorine primer layer 500 mg / m ² / fluorine resin layer). 0 g / m ² / CPP film 30 μm].

[Experimental example 2]
A laminate [ON film] in the same manner as in Example 1 except that a fluorine-based primer layer was formed using a fluorine-based resin solution obtained by adding 20 parts by weight of a melamine-based curing agent to 100 parts by weight of a fluorine-containing copolymer having a hydroxyl group. 25 μm / adhesive layer / chemical conversion treatment layer / aluminum foil 40 μm / chemical conversion treatment layer / fluorine primer layer 500 mg / m ² / fluorine resin layer 3.0 g / m ² / CPP film 30 μm].

[Experimental Example 3]
Instead of the 25 μm-thick ON film as the base material layer, a 9 μm-thick biaxially stretched polyethylene terephthalate film (hereinafter referred to as PET film) and a 15 μm-thick ON film are two-component curable polyurethane-based adhesives The HDI obtained by laminating a fluorine primer layer with a fluorine-based polyol (fluorine-containing copolymer having a hydroxyl group) is used in an amount of 1. Laminate [PET film 9 μm / Adhesive layer / ON film 15 μm / Adhesive layer / Chemical conversion treatment layer / Aluminum foil 40 μm] Except for forming with a fluororesin solution added so as to be 1 equivalent. / Chemical conversion layer / fluorine primer layer 500 mg / m ² / fluorine resin layer 3.0 g / m ² / CPP film 30 μm] Was made.

[Experimental Example 4]
A 15 μm-thick PET film as a base material layer and an aluminum foil in which a chemical conversion treatment layer containing a chemical conversion treatment solution containing an aminated phenol polymer, a trivalent chromium compound, and a phosphorus compound is formed on both sides in advance ( 35 μm thickness) is laminated with a two-component curable polyurethane adhesive, and then HDI is added to the fluorine-based polyol (fluorine-containing copolymer having a hydroxyl group) on the other surface of the aluminum foil. A fluororesin solution added so as to be 1.1 equivalent to 1 equivalent of hydroxyl group (—OH group) of polyol was applied to a solid content of 500 mg / m ² and baked at a drying temperature of 180 ° C. An intermediate laminate having a fluorine-based primer layer was produced. The isocyanate-based curing agent is added to the fluorine-based polyol (fluorine-containing copolymer having a hydroxyl group) on the surface of the fluorine-based primer layer of the intermediate laminate, and 1.1 equivalent to 1 equivalent of the hydroxyl group (-OH group) of the polyol. An unstretched polyethylene film (hereinafter referred to as 30 μm thick) on the surface of the fluororesin layer (fluorinated adhesive layer) formed by applying and drying the fluororesin solution added to 1 to 3.0 g / m ² after drying. , PE film) and heat-pressed to form a laminate [PET film 15 μm / adhesive layer / chemical conversion treatment layer / aluminum foil 35 μm / chemical conversion treatment layer / fluorine primer layer 500 mg / m ² / fluorine resin layer 3. 0 g / m ² / PE film 30 μm].

[Experimental Example 5]
A 15 μm-thick ON film as a base material layer and an aluminum foil having a chemical conversion treatment layer formed on both sides by treatment with a chemical conversion treatment solution containing an aminated phenol polymer, a trivalent chromium compound, and a phosphorus compound in advance ( 35 μm thickness) is laminated with a two-component curable polyurethane adhesive and then blocked with a fluorine-based polyol (fluorine-containing copolymer having a hydroxyl group) on the other surface of the aluminum foil. A fluorinated resin solution in which IPDI was added in an amount of 1.1 equivalent to 1 equivalent of hydroxyl group (—OH group) of polyol was applied to a solid content of 500 mg / m ² and a drying temperature of 180 ° C. An intermediate laminate having a fluorine-based primer layer formed by baking was prepared. The isocyanate-based curing agent is added to the fluorine-based polyol (fluorine-containing copolymer having a hydroxyl group) on the surface of the fluorine-based primer layer of the intermediate laminate, and 1.1 equivalent to 1 equivalent of the hydroxyl group (-OH group) of the polyol. A 30 μm thick CPP film was thermocompression-bonded to the surface of the fluororesin layer (fluorinated adhesive layer) formed by applying and drying the fluororesin solution added to 1 to 3.0 g / m ² after drying. To produce a laminate [ON film 15 μm / adhesive layer / chemical conversion layer / aluminum foil 35 μm / chemical conversion layer / fluorine primer layer 500 mg / m ² / fluorine resin layer 3.0 g / m ² / CPP film 30 μm] did.

[Experimental Example 6]
A 25 μm-thick ON film as a base material layer and an aluminum foil in which a chemical conversion treatment layer is formed on both surfaces by treatment with a chemical conversion treatment solution containing an aminated phenol polymer, a trivalent chromium compound and a phosphorus compound in advance ( 40 μm thickness) is laminated with a two-component curable polyurethane adhesive, and the other surface of the aluminum foil is coated with a fluorine-based polyol (fluorine-containing copolymer having a hydroxyl group) with an isocyanate. Formed by applying and drying a fluororesin solution to which a curing agent is added in an amount of 1.1 equivalents relative to 1 equivalent of a polyol hydroxyl group (—OH group) after drying to 3.0 g / m ² A laminated body [ON film 25 μm / adhesive layer / chemical conversion treatment layer / aluminum foil 4] is formed by heat-pressing a 30 μm thick CPP film on the surface of the fluorine resin layer (fluorine adhesive layer). 0 μm / chemical conversion treatment layer / fluorine-based resin layer 3.0 g / m ² / CPP film 30 μm].

[Experimental Example 7]
A 25 μm-thick ON film as a base material layer and an aluminum foil in which a chemical conversion treatment layer is formed on both surfaces by treatment with a chemical conversion treatment solution containing an aminated phenol polymer, a trivalent chromium compound and a phosphorus compound in advance ( 40 μm thickness) and 30 μm CPP film laminated via a two-component curable polyurethane adhesive [ON film 25 μm / adhesive layer / chemical conversion layer / aluminum foil 40 μm / chemical conversion layer / adhesive layer / CPP film 30 μm]. The application amount of the two-component curable polyurethane adhesive was 3.0 g / m ² after drying in any example.

  About the laminated body of Experimental Examples 1-7 produced above, the electrolytic solution resistance and moisture permeability were evaluated by the following evaluation methods, and the evaluation results are summarized in Table 1.

〔Evaluation methods〕
Electrolytic solution resistance evaluation method:
Electrolytic solution [lithium hexafluorophosphate dissolved in a mixed solution [ethylene carbonate / diethyl carbonate / dimethyl carbonate = 1/1/1 (volume ratio) to obtain a 1 mol / liter lithium hexafluorophosphate solution] ] Were immersed in a 25 × 75 mm square test piece, stored in a thermostatic bath at 85 ° C. for 30 days, and the number of days until the inner layer from the aluminum foil peeled was evaluated.

Moisture permeability evaluation method:
The laminate is cut to produce a strip of 100 × 100 mm, and the strip is folded in half and heat-sealed so that one of the short sides is 10 mm wide and the long side is 3 mm wide, and the other short side is In addition to producing an open 100 × 50 mm outer bag, 3 g of a solvent [ethylene carbonate / diethyl carbonate / dimethyl carbonate = 1/1/1 (volume ratio) in a dry room (dew point−50 ° C.) )] Was injected, and a moisture permeability evaluation sample in which the opening was heat-sealed with a width of 10 mm was prepared. This moisture permeability evaluation sample was stored in a constant temperature and humidity chamber at 60 ° C. and 90% RH for 7 days, and the amount of increase in moisture inside the sample was measured by the Karl Fischer method. The heat seal conditions on the short side were 190 ° C., 2.0 MPa, 3.0 seconds, and the heat seal conditions on the long side were 190 ° C., 1.0 MPa, 3.0 seconds. The unit is water permeation (ppm) per 7 days.

  As is clear from Table 1, in the electrolytic solution resistance, the laminates of Experimental Examples 1 to 5 are remarkably superior to the laminate of Experimental Example 7 due to the effect of providing the fluorine-based primer layer and the Experimental Examples. Even when compared with the laminate of No. 6, the performance was excellent. Moreover, also about the water permeability, the laminated body of Experimental Examples 1-6 laminated | stacked with the fluorine resin layer (fluorine-type adhesive bond layer) showed the performance superior to the laminated body of Experimental Example 7. FIG. In the experimental example, an example in which a fluorine-based primer layer is provided on the surface of the chemical conversion treatment layer after laminating the base layer and the aluminum foil provided with the chemical conversion treatment layer on both sides is shown. Is not limited thereto, and may be provided on the surface of the chemical conversion treatment layer of the aluminum foil before being laminated with the base material layer.

It is a figure showing the layer composition of one example of the layered product concerning the present invention diagrammatically. It is a figure explaining one Example of the form of a lithium battery. It is a figure explaining the other Example of the form of a lithium battery.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laminated body 2 Base material layer 3 Aluminum foil 4 Chemical conversion treatment layer 5 Fluorine-type primer layer 6 Fluorine-type adhesive layer 7 Thermal adhesive resin layer

Claims (2)

In a laminate in which at least a base material layer, an aluminum foil, a chemical conversion treatment layer, a fluorine primer layer, a fluorine adhesive layer, and a thermal adhesive resin layer are sequentially laminated, the fluorine primer layer and the fluorine adhesive layer are hydroxyl groups. Formed of a composition containing a fluorine-containing copolymer containing a fluorine-containing copolymer and a curing agent that reacts with the fluorine-containing copolymer, and the fluorine-based primer layer is formed by applying and baking the composition on the surface of the chemical conversion treatment layer A layered product characterized by being a layer that has been formed. The laminate according to claim 1, wherein the curing agent of the fluorine-based primer layer is selected from the group consisting of blocked isocyanate, a polymer thereof, and a melamine curing agent.

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