TWI687309B - Laminate for nonaqueous battery packages - Google Patents

Abstract

The invention provides a laminate for nonaqueous battery packages which is able to improve the manufacturing efficiency of nonaqueous battery by increasing mechanical strength of the laminate for nonaqueous battery packages, and reducing failure occurrence during drawing. The laminate for battery packages (10) is formed by laminating a SUS leaf (12) and a sealant layer (13). A surface coating layer (17) with thickness of 0.05 μm～1.0 μm is formed on at least the sealant layer (13) side of the SUS leaf (12), by drying and hardening a water soluble coating material which contains of water soluble resin and fluorinated metal compound.  The SUS leaf (12) comprises a coating layer (16) which is formed on the opposite surface side of sealant layer (13) side.

Description

Non-aqueous battery outer packaging laminate

The present invention relates to a laminate for non-aqueous battery packaging used in packaging materials for secondary batteries such as lithium ion batteries and electric double layer capacitors.

In recent years, with the global environmental problems rising, the popularization of electric vehicles and the effective use of natural energy such as wind power generation and solar power generation have become issues. Along with this, in these technical fields, secondary batteries such as lithium ion batteries and electric double layer capacitors have received attention as storage batteries for storing electrical energy.

As a container for lithium ion batteries used in electric vehicles and the like, in order to achieve miniaturization and weight reduction, a container composed of a laminated body for battery packaging laminated with a metal foil and a resin layer (for example, , Refer to Patent Document 1).

When manufacturing a secondary battery using the container for outer packaging prepared from the laminated body for battery outer packaging, for example, it is performed as follows.

The laminate for battery outer packaging is shaped into a tray having recesses by drawing molding or the like, and serves as a container body. The battery is accommodated in the recess of the container body. Next, a cover material composed of a laminate for battery outer packaging is overlaid on the container body, and the flange portion of the container body and the side edge portion of the cover material are heat-sealed, thereby obtaining a container for packaging Secondary battery with battery.

Existing technical literature

Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2000-357494.

Problems to be solved by the invention

In recent years, in applications such as batteries for electric vehicles, an outer container for large batteries having a larger outer size than before and an outer container that can reduce the thickness of the laminate for the outer battery and increase the internal volume . However, it is necessary to form a container body with a deeper recess in a container for an outer packaging for a large battery, which increases technical difficulty. For example, when the laminate for battery outer packaging is subjected to deep drawing, peeling between the metal foil and the resin layer and damage (breakage, etc.) of the laminate for battery outer packaging may occur. In addition, when the thickness of the laminate for a battery outer package is reduced, there is a problem that the mechanical strength such as puncture strength decreases.

Therefore, it is desirable to improve the mechanical strength of the laminate for battery outer packaging while reducing defects that occur during drawing and to increase the manufacturing yield of non-aqueous batteries.

The present invention has been completed in view of the above circumstances, and an object of the present invention is to provide a laminate for nonaqueous battery outer packaging, which can improve the mechanical strength of the laminate for nonaqueous battery outer packaging and prevent defects during drawing molding, Thereby improving the production efficiency of non-aqueous batteries.

Technical means to solve problems

In order to solve the above problems, the present invention provides a laminate for nonaqueous battery outer packaging, which is laminated with a SUS foil and a sealing layer, and a surface covering layer having a thickness of 0.05 μm to 1.0 μm is formed on at least the sealing layer side of the SUS foil The surface coating layer is formed by drying and curing a water-soluble paint containing water-soluble resin and metal fluoride.

The SUS foil has a coating layer on a side opposite to the sealing layer side. The coating layer is selected from polyurethane resin, acrylic resin, polyvinylidene chloride, vinylidene chloride-vinyl chloride copolymer resin, Anhydride-modified polypropylene resin, polyester resin, epoxy resin, phenolic resin, phenoxy resin, fluororesin, cellulose ester resin, cellulose ether resin, polyamide resin, polyphenylene ether resin, polyphenylene sulfide At least one resin in the resin group consisting of resin, polyarylether resin, and polyetheretherketone resin is formed.

It is preferable that the aforementioned coating layer is a thin-film cured layer formed by coating and drying a solvent-based paint prepared by dissolving the aforementioned resin in an organic solvent.

Preferably, the aforementioned coating layer is colored with achromatic or chromatic coloring agent.

Preferably, the aforementioned water-soluble paint further contains an organic chelating agent.

It is preferable that the metal fluoride is a substance that cross-links the water-soluble resin and inactivates the surface of the SUS foil.

effect

According to the present invention, since the resin coating layer is formed on one surface of the SUS foil, the mechanical strength and slidability of the laminate for battery outer packaging can be improved. Since the resin coating layer is formed by coating, it is firmly bonded to the SUS foil.

Generally, the workability of SUS foil is inferior to other metal foils such as aluminum foil. Therefore, it is difficult to set the conditions when deep drawing is performed, and the phenomenon of peeling from adjacent layers is also likely to occur.

In contrast, in the present invention, since the resin coating layer is firmly bonded to the SUS foil, peeling can be prevented. In addition, since the resin coating layer improves mechanical strength and slidability, when the recessed portion is formed by drawing molding, it is possible to reduce breakage (breakage, etc.) and deformation of the laminate for battery outer packaging.

Thereby, even when deep drawing is performed, it is possible to prevent a decrease in battery production efficiency due to a molding defect of the battery packaging container. In addition, since it is difficult to cause damage to the laminate for battery outer packaging and the like, it is possible to prevent a decrease in battery performance and a fire caused by electrolyte leakage or water infiltration.

In the present invention, by forming the resin coating layer, it is possible to prevent the phenomenon that the surface of the laminate for battery outer packaging is damaged by external force. Furthermore, even in the case where the laminate for a battery outer package is in contact with the electrolyte, it is possible to prevent the appearance of the battery from changing (such as discoloration).

Since the coating layer is formed by coating, it is possible to form a laminate for a battery outer package thinner than when a resin film is laminated with an adhesive. As a result, the battery packaging container can be made thinner, the internal volume can be increased, and the battery volume efficiency can be improved.

FIG. 1 shows a laminate 10 for a battery outer package according to a first embodiment as a laminate for a non-aqueous battery outer package of the present invention (hereinafter sometimes simply referred to as “laminate for a battery outer package”). In addition, FIG. 2 shows a container 20 for a non-aqueous battery outer package for a lithium ion battery manufactured using the laminated body 10 for a battery outer package of the present invention (hereinafter sometimes simply referred to as a “container 20 for a battery outer package ") and secondary battery 40.

FIG. 2 shows a perspective view of a secondary battery 40 produced using the container 20 for battery packaging as an example of the container for battery packaging of the present invention. The secondary battery 40 is formed by incorporating a lithium ion battery 27 in the battery packaging container 20.

The container 20 for battery outer packaging is formed by superimposing the container body 30 and the cover material 33 and heat-sealing the peripheral portion 29, wherein the container body 30 is formed by the first The laminated body 10 for battery packaging according to an embodiment is constituted, and the covering material 33 is composed of the laminated body 10 for battery packaging. Reference numeral 28 is an electrode lead connected to the positive electrode and the negative electrode of the lithium ion battery 27.

As shown in FIG. 1, the laminate 10 for a battery outer package of the present invention has a structure in which a SUS foil 12 and a sealing layer 13 are laminated, and is provided on a side (upper side of FIG. 1) of the SUS foil 12 opposite to the sealing layer 13. There is a coating layer 16 (first coating layer).

In this specification, SUS foil refers to a metal foil made of stainless steel.

A printing layer 15 (second coating layer) is formed between the SUS foil 12 and the coating layer 16.

On the sealing layer 13 side (lower side in FIG. 1) and the coating layer 16 side (upper side in FIG. 1) of the SUS foil 12, surface covering layers 17 and 18 are formed, respectively.

In addition, the laminate 10 for a battery outer package has a printed layer 15, but the printed layer 15 may not be provided.

Hereinafter, each layer will be described in detail.

The SUS foil 12 is a metal foil made of stainless steel. For example, it is made of Austenite (also called Vostian iron system), Ferrite (Ferrite, also called ferrite iron system), and Martensite (also known as Martensite). It is made of stainless steel such as Ma Tian loose iron. As the austenitic system, there are SUS304, SUS316, SUS301, etc., as the ferrite system, SUS430, etc., as the martensite system, SUS410, etc.

The SUS foil 12 has higher tensile strength and other mechanical strengths than other metal foils such as aluminum foil. Therefore, the formation of recesses by drawing molding can reduce the occurrence of pinholes, which is not likely to cause battery leakage. In addition, the corrosion resistance of SUS foil 12 is superior to other metal foils, so it is less likely to cause deterioration due to corrosion.

The thickness of the SUS foil 12 can be set to, for example, 5 μm to 100 μm. The thickness of the SUS foil 12 is preferably 5 μm to 50 μm.

By setting the thickness of the SUS foil 12 to 5 μm or more, it is possible to impart sufficient strength (puncture strength, etc.) to the laminated body 10 for battery packaging, and improve the durability of the secondary battery 40. In addition, by setting the thickness of the SUS foil 12 to 50 μm or less, it is possible to impart sufficient drawing workability to the laminate 10 for battery outer packaging.

The surface coating layers 17 and 18 are layers formed by drying and curing a water-soluble paint containing a water-soluble resin and a metal fluoride. It is preferable that the aforementioned water-soluble paint contains an organic chelating agent.

The thickness of the surface coating layers 17 and 18 is set to 0.05 μm or more (preferably a thickness exceeding 0.2 μm). By setting the thickness of the surface coating layers 17 and 18 to be 0.05 μm or more, sufficient corrosion resistance can be imparted to the laminate 10 for battery packaging, and the adhesion strength between the SUS foil 12 and the sealing layer 13 and the SUS foil can be improved 12 Adhesion strength between the layer on the upper side and it.

The thickness of the surface coating layers 17 and 18 is set to 1.0 μm or less (preferably 0.5 μm or less). By setting the thickness of the surface coating layers 17 and 18 to 1.0 μm or less, it is possible to increase the adhesive strength between the SUS foil 12 and the sealing layer 13 while suppressing the material cost.

The thickness of the surface coating layers 17 and 18 is preferably in a range of more than 0.2 μm and 0.5 μm or less.

As the water-soluble resin, one or more of polyvinyl alcohol-based resin and polyvinyl ether-based resin are preferably used.

The polyvinyl alcohol-based resin refers to at least one water-soluble resin selected from polyvinyl alcohol resins and modified polyvinyl alcohol resins.

The polyvinyl alcohol-based resin can be produced, for example, by saponifying a polymer of a vinyl ester monomer or a copolymer thereof.

Examples of polymers or copolymers of vinyl ester monomers include fatty acid vinyl esters such as vinyl formate, vinyl acetate, and vinyl butyrate, and aromatic vinyl esters such as vinyl benzoate. Homopolymers or copolymers of vinyl ester monomers, and copolymers of other monomers copolymerizable therewith.

Examples of other copolymerizable monomers include olefins such as ethylene and propylene, monomers containing an ether group such as alkyl vinyl ether, diacetone acrylamide, diacetone (meth)acrylate, and ethyl acetate. Carbonyl (ketone)-containing monomers such as allyl acetate and acetyl acetate, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride, vinyl halide such as vinyl chloride and vinylidene chloride, and Saturated sulfonic acids, etc.

The degree of saponification of the polyvinyl alcohol-based resin is usually preferably 90 to 100 mol%, and more preferably 95 mol% or more.

Examples of the polyvinyl alcohol-based resins that can be used in the present invention include alkyl ether modified polyvinyl alcohol resins, carbonyl modified polyvinyl alcohol resins, acetoacetoxy modified polyvinyl alcohol resins, and acetamide Modified polyvinyl alcohol resin, acrylonitrile modified polyvinyl alcohol resin, carboxyl modified polyvinyl alcohol resin, silicone modified polyvinyl alcohol resin, ethylene modified polyvinyl alcohol resin, etc. Among them, preferred are alkyl ether modified polyvinyl alcohol resins, carbonyl modified polyvinyl alcohol resins, carboxyl modified polyvinyl alcohol resins, and acetylated ethylvinyl modified polyvinyl alcohol resins.

Examples of commercially available products of polyvinyl alcohol-based resins that are generally available include, for example, J-POVAL (J-ポバール) DF manufactured by JAPAN VAM & POVAL CO., LTD. (Japan ビポパール Inc.). -20 (trade name), Crossmer (Cross マー) H series (trade name), etc. manufactured by Nippon Carbide Industries Co., Inc. The polyvinyl alcohol-based resin may use one kind or a mixture of two or more kinds.

Examples of polyvinyl ether-based resins include ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, and 2-ethyl Hexyl vinyl ether, cyclohexyl vinyl ether, norbornyl vinyl ether, allyl vinyl ether, norbornenyl vinyl ether, 2-hydroxyethyl vinyl Homopolymers or copolymers of aliphatic vinyl ethers such as ether and diethylene glycol monovinyl ether, and copolymers of other monomers copolymerizable therewith. As the other monomer copolymerizable with the vinyl ether-based monomer, the same monomers as the other monomer copolymerizable with the vinyl ester-based monomer mentioned above may be mentioned.

In particular, the monomer contains 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 2-hydroxypropyl vinyl ether, monovinyl ether of various diols or polyols, etc. The hydroxyl group-containing aliphatic vinyl ether-based polyvinyl ether resin has water solubility and can undergo a cross-linking reaction with the hydroxyl group, and therefore, can be applied to the present invention.

Since these vinyl ether resins can be used in the resin manufacturing (polymerization) process, unlike polyvinyl alcohol resins made from vinyl ester polymers, saponification treatment is not necessary And manufacture. In addition, a copolymer containing a vinyl ester-based monomer and a vinyl ether-based monomer, or a vinyl alcohol-vinyl ether copolymer obtained by saponifying it may also be used. Mixtures of polyvinyl alcohol-based resins and polyvinyl ether-based resins other than polyvinyl ether-based resins can also be used.

As the water-soluble resin, only one of polyvinyl alcohol-based resin and polyvinyl ether-based resin may be used, or both of them may be used in combination.

The metal fluoride is preferably water-soluble from the viewpoint of mixing with the aforementioned water-soluble resin.

Specific examples of the metal fluoride include chromium fluoride, iron fluoride, zirconium fluoride, titanium fluoride, hafnium fluoride, fluorotitanic acid, and salts thereof.

Metal fluoride has the effect of improving electrolyte resistance. That is, the surface of the SUS foil 12 can be passivated, and the corrosion resistance to the electrolyte can be improved. The metal fluoride also has the effect of crosslinking the aforementioned water-soluble resin.

Organic chelating agents are organic substances that can chemically bond with cations and form metal ion complexes.

The organic chelating agent causes the metal compound derived from metal fluoride (chromium oxide, etc.) to bond with the aforementioned water-soluble resin to increase the compressive strength of the surface coating layers 17, 18. Therefore, even if the thickness of the surface coating layers 17, 18 is For example, when it exceeds 0.2 μm and is 1.0 μm or less, the surface coating layer does not become brittle, and cracks and peeling do not occur. Thereby, the adhesion strength between the SUS foil 12 and the sealing layer 13 and the adhesion strength between the SUS foil 12 and the layer on the upper layer side can be improved.

In addition, the organic chelating agent has a function of making the water-soluble resin resistant to water by chemical reaction with the water-soluble resin or metal fluoride.

As the organic chelating agent, for example, aminocarboxylic acid-based chelating agents, phosphonic acid-based chelating agents, hydroxycarboxylic acid-based chelating agents, (poly)phosphoric acid-based chelating agents can be used.

Examples of the aminocarboxylic acid chelating agent include nitrilotriacetic acid (NTA), hydroxyethyliminodiacetic acid (HIDA), ethylenediaminetetraacetic acid (EDTA), and hydroxyethylethylenediamine Triacetic acid (HEDTA), diethylenetriaminepentaacetic acid (DTPA), triethylenetetraminehexaacetic acid (TTHA), transcyclohexanediaminetetraacetic acid (CyDTA), 1,2-propanediaminetetraacetic acid (1, 2-PDTA), 1,3-propanediaminetetraacetic acid (1,3-PDTA), 1,4-butanediaminetetraacetic acid (1,4-BDTA), 1,3-diamino-2-hydroxyl Propane tetraacetic acid (DPTA-OH), glycol ether diamine tetraacetic acid (GEDTA), ethylenediamine o-hydroxyphenylacetic acid (EDHPA), SS-ethylenediamine disuccinic acid (SS-EDDS), ethylenediamine Disuccinic acid (EDDS), β-alanine diacetic acid (ADA), methylglycine diacetic acid (MGDA), L-aspartic acid-N,N-diacetic acid (ASDA), L-glutamic acid -N,N-diacetic acid (GLDA), N,N'-bis(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid (HBEDDA).

As the phosphonic acid chelating agent, for example, N,N,N-trimethylenephosphonic acid (NTMP), 1-hydroxyethylene-1,1-diphosphonic acid (HEDP), ethylenediamine-N ,N,N',N'-tetramethylenephosphonic acid (EDTMP), diethylenetriamine pentamethylenephosphonic acid (DTPMP), 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC).

Examples of the hydroxycarboxylic acid chelating agent include glycolic acid, citric acid, malic acid, gluconic acid, and glucoheptonic acid.

Examples of (poly)phosphoric acid chelating agents include metaphosphoric acid, tripolyphosphoric acid, tetrapolyphosphoric acid, pyrophosphoric acid, orthophosphoric acid, hexametaphosphoric acid, and salts thereof.

As a commercially available product of an organic chelating agent that is generally available, for example, there are Chelest PD-4H (trade name) (belonging to PDTA) manufactured by Chelest Corporation (キレスト Inc.), and Chelest PH-540 (trade name) (being belonging to EDTMP) )Wait.

The amount of the water-soluble resin contained in the water-soluble paint is preferably 0.1 to 1% by mass.

By setting the addition amount of the water-soluble resin to 0.1% by mass or more, the adhesion strength between the SUS foil 12 and the sealing layer 13 can be improved. In addition, by setting the addition amount of the water-soluble resin to 1% by mass or less, the adhesion strength between the SUS foil 12 and the sealing layer 13 can be improved.

The amount of metal fluoride contained in the water-soluble paint is preferably 0.1 to 2.5% by mass (preferably 0.8 to 2.5% by mass).

By setting the amount of metal fluoride added to 0.1% by mass or more, the corrosion resistance of the SUS foil 12 to the electrolyte can be improved. In addition, by setting the amount of metal fluoride added to 2.5% by mass or less, it is possible to avoid precipitation in the water-soluble paint and suppress unevenness of the coating film.

When an organic chelating agent is used, the amount of the organic chelating agent contained in the water-soluble paint is preferably 0.1 to 1% by mass (preferably 0.3 to 1% by mass).

By setting the amount of metal fluoride added to 0.1% by mass or more, the compressive strength of the surface coating layers 17 and 18 can be improved, and cracking and peeling of the surface coating layers 17 and 18 can be suppressed. In addition, by setting the addition amount of the organic chelating agent to 1% by mass or less, it is possible to impart sufficient strength to the surface coating layers 17 and 18.

The surface coating layers 17 and 18 can be formed by applying the water-soluble paint to the SUS foil 12 and heating and drying, baking, and cross-linking in an oven or the like.

In addition, in the laminated body 10 for battery packaging shown in FIG. 1, the surface covering layers 17 and 18 are formed on both surfaces of the SUS foil 12, but as long as the surface covering layer is formed at least on the sealing layer 13 of the SUS foil 12 Side. That is, the configuration in which the surface covering layer 18 is omitted from the laminate 10 for battery outer packaging of FIG. 1 (the laminate 60 for battery outer packaging shown in FIG. 5) may be adopted.

The coating layer 16 (first coating layer) is selected from polyurethane resin, acrylic resin, polyvinylidene chloride, vinylidene chloride-vinyl chloride copolymer resin, maleic anhydride modified polypropylene resin, polyester resin, Epoxy resin, phenolic resin, phenoxy resin, fluororesin, cellulose ester resin, cellulose ether resin, polyamide resin, polyphenylene ether resin (PPE), polyphenylene sulfide resin (PPS), polyarylene ether It is formed by at least one resin in the resin group consisting of resin (PAE) and polyetheretherketone resin (PEEK).

In the coating layer 16, one kind of resin constituting the aforementioned resin group may be used alone, or two or more kinds thereof may be used in combination.

The coating layer 16 is preferably made of a material having excellent heat resistance.

The coating layer 16 is preferably the outermost layer of the laminate 10 for battery outer packaging.

By forming the coating layer 16, the insulation of the laminated body 10 for battery outer packaging can be improved, and the surface of the laminated body 10 for battery outer packaging can be prevented from being scratched. In addition, even in the case where the laminate 10 for the battery outer package is in contact with the electrolyte, it is possible to prevent a change in appearance (discoloration, etc.).

It is preferable that the coating layer 16 is a thin-film cured layer formed by coating and drying a solvent-based paint, wherein the solvent-based paint is prepared by dissolving the aforementioned resin in an organic solvent.

Examples of organic solvents include hydrocarbon solvents such as toluene, xylene, n-hexane, cyclohexane, methylcyclohexane, n-heptane, tridecane, and tetradecane; ethyl acetate and butyl acetate Esters, methoxybutyl acetate, Acetic acid cellosolve, amyl acetate, n-propyl acetate, isopropyl acetate and other ester solvents; acetone, methyl ethyl ketone (MEK), methyl Isobutyl ketone, diisobutyl ketone (DIBK), cyclohexanone, diacetone alcohol (DAA) and other ketone solvents; methanol, ethanol, butanol, propanol, isopropanol, n-propanol and other alcohol solvents; Alcohol ether solvents such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, dioxane, ethylene glycol dimethyl ether, etc. The organic solvent may be used alone or in combination of two or more.

In solvent-based paints, additives such as desiccants and stabilizers may also be added.

For the solvent-based paint used to form the coating layer 16, for example, a known printing method such as an offset printing method, a gravure printing method, and a screen printing method can be used for application.

The coating layer 16 can be colored by adding achromatic or chromatic colorants to the aforementioned solvent-based paint.

The color of the coating layer 16 can be arbitrarily selected. The coating layer 16 may be continuously and uniformly colored in all regions (or partial regions), or may be colored in mutually different colors (or mutually the same color) in a plurality of regions.

The coating layer 16 can also be colored to display characters, graphics, images, patterns, and the like. These characters, etc., for example, can be displayed as a brand name, a manufacturer, or the like.

By coloring the coating layer 16, the design of the laminate 10 for a battery outer package can be improved.

As the aforementioned coloring agent, pigments or dyes can be used.

As the pigment, for example, quinacridones, anthraquinones, perylenes, pyrenes, diketopyrrolopyrroles, isoindolinones, condensed azos, benzimidazolones, Monoazo, insoluble azo, naphthol, yellow anthracene copper, anthracene pyrimidine, quinoline yellow, picanthrone, pyrazolone, thioindigo, anthraquinone, Organic pigments such as dioxazines, phthalocyanines, indanthraquinones, etc.; metal complexes such as nickel dioxine yellow, copper methylimide yellow; titanium oxide, iron oxide, zinc oxide, etc. Metal oxides; metal salts such as barium sulfate and calcium carbonate; inorganic pigments such as carbon black, aluminum and mica.

Examples of the dye include azo, quinoline, stilbene, thiazole, indigo, anthraquinone, and oxazine.

The coating layer 16 may be colored by using a solvent-based paint containing ink. The ink is prepared, for example, by adding the aforementioned colorant to an ink binder resin such as polyurethane or acrylic.

The thickness of the coating layer 16 can be, for example, 0.1 μm or more. More preferably, the coating layer 16 has a thickness of 2 μm or more.

By setting the thickness of the coating layer 16 to 2 μm or more, the effect of preventing scratches on the surface of the laminated body 10 for battery outer packaging can be improved while improving insulation. In addition, even when the laminate 10 for the battery outer package is in contact with the electrolyte, it is possible to reliably prevent a change in appearance (discoloration, etc.).

The thickness of the coating layer 16 can be, for example, 20 μm or less. By setting the thickness of the coating layer 16 in the range of 2 to 20 μm, the overall thickness of the laminate 10 for battery packaging can be suppressed.

The static friction coefficient (in accordance with JIS K7125) of the surface of the coating layer 16 is preferably 0.3 or less.

By setting the static friction coefficient within this range, it is possible to reduce damage and deformation of the laminated body 10 for battery packaging during drawing, and drawing can be easily performed.

The printed layer 15 (second coating layer) can be set to the same structure as the coating layer 16.

The printed layer 15 is formed of a material exemplified as a material usable in the coating layer 16 (at least one resin selected from the aforementioned resin group). The constituent material of the printing layer 15 may be the same as the constituent material of the coating layer 16 or may be a different material from the constituent material of the coating layer 16.

The printed layer 15 and the adhesive layer 14 are preferably a thin-film cured layer formed by applying and drying a solvent-based coating material similar to the coating layer 16, wherein the solvent-based coating material dissolves the aforementioned resin in Prepared in organic solvents.

The printing layer 15 and the adhesive layer 14 can be colored by adding the colorant to the solvent-based paint in the same manner as the coating layer 16. The color of the printing layer 15 can be arbitrarily selected. The printing layer 15 and the adhesive layer 14 may be continuously and uniformly colored in all areas (or partial areas), or may be colored in mutually different colors (or the same color) in a plurality of areas.

The printed layer 15 and the adhesive layer 14 can also be colored to display characters, graphics, images, patterns, and the like. These characters, etc., for example, can be displayed as a brand name, a manufacturer, or the like.

By coloring the printed layer 15 and the adhesive layer 14, it is possible to improve the design of the laminated body 10 for battery outer packaging.

The preferred thickness of the printed layer 15 is, for example, 0.1 μm to 10 μm.

The printing layer 15 can be formed by a well-known printing method such as an offset printing method, a gravure printing method, and a screen printing method.

In addition, the laminated body 10 for battery packaging illustrated in FIG. 1 has the printed layer 15, but it may be configured without the printed layer 15 (the laminated body 70 for battery packaging shown in FIG. 6 ). In addition, the configuration in which the surface covering layer 18 and the printed layer 15 are omitted from the laminate 10 for battery outer packaging of FIG. 1 (the laminate 80 for battery outer packaging shown in FIG. 7) may be used.

The sealing layer 13 is made of polyolefin-based resin, and is the innermost layer in the secondary battery 40 (see FIG. 2 ).

The reason why the sealing layer 13 is provided on the innermost side is because the polyolefin-based resin has excellent resistance to the electrolyte of the lithium ion battery and has good heat sealability. Here, the heat sealability refers to the seal stability at high temperature.

It is preferable that the polyolefin resin constituting the sealing layer 13 mainly contains any one of polypropylene resin and polyethylene resin.

The sealing layer 13 has a single-layer structure, or has a structure composed of a multilayer laminated film.

Preferably, the surface of the sealing layer 13 on the interface side with the SUS foil 12 is composed of a heat-adhesive polyolefin resin containing a polyolefin resin selected from maleic anhydride-modified polyolefin resin (first polymer). Olefin resin), an epoxy-containing resin and polyolefin resin mixture material (second polyolefin resin), and an oxazoline group-containing resin and polyolefin resin mixture material (third polyolefin resin) ) One or more of the resin group composed.

When the sealing layer 13 is a single layer, it is preferable that the sealing layer 13 is composed of the aforementioned thermally adhesive polyolefin resin.

When the sealing layer 13 has a multilayer structure, it is preferable that the sealing layer 13 has a layer composed of the aforementioned thermally adhesive polyolefin resin on the interface side with the SUS foil 12.

As the thermally adhesive polyolefin resin, one kind of the first polyolefin resin to the third polyolefin resin may be used alone, or two or more kinds thereof may be used in combination.

The first polyolefin resin to the third polyolefin resin are strongly bonded to the water-soluble resin contained in the surface covering layer 17, and therefore, the bonding strength between the sealing layer 13 and the surface covering layer 17 can be improved.

When two or more of the first polyolefin resin to the third polyolefin resin are used, it is preferable to further knead and mix these polyolefin resins.

The maleic anhydride-modified polyolefin resin is a resin that modifies a part of polyolefin resin molecules with maleic anhydride.

As commercially available products of maleic anhydride-modified polyolefin resins generally available, there are Admer (trade name: "アドマー") manufactured by Mitsui Chemicals Co., Ltd. (as acid-modified polyethylene, for example, SF600, SF700, NE060; as acid-modified polypropylene, for example, QF551), Modic (trade name: "MOディック") manufactured by Mitsubishi Chemical Corporation (as acid-modified polyethylene, for example, M545; as acid-modified polypropylene , For example, P555).

As the epoxy group-containing resin, a resin obtained by modifying a part of a polyolefin resin molecule into an epoxy group; and melt-mixing an epoxy compound or an epoxy group-containing resin with a polyolefin resin can be used. Resin.

Examples of preferred commercially available epoxy compounds that can be used in the present invention include "Epikote 1001" manufactured by Mitsubishi Chemical Corporation.

In addition, as the epoxy group-containing resin, there are "MODIPER (Modal) A4100" manufactured by Nippon Oil and Fats Co., Ltd. and the like.

As the oxazoline group-containing resin, a resin in which a part of polyolefin resin molecules are modified to an oxazoline group; and a resin obtained by melt-mixing an oxazoline compound and a polyolefin resin can be used.

As the oxazoline compound that can be used in the present invention, there are 2-isopropenyl-2-oxazoline and the like. As a commercially available product preferable for the oxazoline compound, for example, "EPOCROS" manufactured by Nippon Catalyst Co., Ltd. and the like.

The thickness of the sealing layer 13 is preferably 20 μm to 50 μm. By setting the thickness of the sealing layer 13 within this range, it is possible to increase the pressure resistance of the heat-sealed portion and suppress the infiltration of moisture into the battery packaging container 20.

In addition, by setting the thickness of the sealing layer 13 within this range, it is possible to suppress the overall thickness of the laminated body 10 for battery packaging, and to achieve a thinner secondary battery 40.

When the sealing layer 13 has a multilayer structure, since it has the aforementioned thermally adhesive polyolefin resin layer, it can be adhered to the SUS foil 12 by thermal lamination.

The adhesion strength between the sealing layer 13 and the SUS foil 12 is measured in accordance with the measurement method B (180 degree peel) specified in JIS C6471, and is preferably 5 N/15 mm or more.

The overall thickness of the laminate 10 for battery packaging can be set to, for example, 70 μm or less. Based on this, the thickness of the secondary battery 40 can be reduced.

It is preferable that the tensile elongation at break of the laminate 10 for battery packaging is 40% or more in both the MD and TD directions.

If the tensile elongation at break is within this range, when the recess is formed by drawing, the corners are sufficiently stretched, and therefore, breakage does not occur.

The tensile elongation at break was calculated according to JIS K7127 and measured at a tensile speed of 50 mm/min.

Examples of the non-aqueous battery using a laminate for battery packaging include a non-aqueous battery using an organic electrolyte in an electrolytic solution such as a lithium ion battery and an electric double layer capacitor as a secondary battery. The organic electrolyte is generally an organic electrolyte using carbonates such as propylene carbonate (PC), diethyl carbonate (DEC), and ethylene carbonate as a medium, but it is not particularly limited thereto.

Next, a method of manufacturing the secondary battery 40 shown in FIG. 2 will be described.

First, as shown in FIG. 3A, the laminate 10 for battery outer packaging is formed into a tray shape having a recess 31 by drawing molding or the like, and a container body 30 is obtained. The depth of the recess 31 may be, for example, 2 mm or more.

A lithium ion battery (lithium ion battery 27 in FIG. 2) is accommodated in the recess 31 of the container body 30.

Next, as shown in FIG. 3 b, the cover material 33 composed of the laminated body 10 for battery outer packaging is overlaid on the container body 30, and the flange portion 32 of the container body 30 and the peripheral portion 34 of the cover material 33 are Heat sealing is performed, thereby obtaining the secondary battery 40 shown in FIG. 2.

Since the laminated body 10 for battery outer packaging of the present invention is formed with the coating layer 16, the mechanical strength and slidability of the laminated body 10 for battery outer packaging can be improved. Since the coating layer 16 is formed by coating, it is firmly bonded to the SUS foil 12.

Generally, SUS foils are inferior in workability compared to other metal foils such as aluminum foils. Therefore, it is difficult to set conditions when performing deep drawing molding. In addition, the phenomenon of peeling off from the adjacent layer is easily caused.

Conversely, in the laminate 10 for a battery outer package of the present invention, since the coating layer 16 is firmly bonded to the SUS foil 12, peeling can be prevented. In addition, since the coating layer 16 improves mechanical strength and slidability, when the concave portion is formed by drawing, damage (breakage, etc.) and deformation of the laminated body 10 for battery outer packaging can be reduced.

Therefore, even when deep drawing is performed, it is possible to prevent a decrease in the production efficiency of the secondary battery 40 due to a molding defect of the battery packaging container 20. In addition, since it is difficult to cause damage to the laminated body 10 for battery outer packaging and the like, it is possible to prevent a decrease in battery performance and a fire caused by electrolyte leakage or water infiltration.

In addition, by forming the coating layer 16, it is possible to prevent the phenomenon of damage to the surface of the laminate 10 for external battery packaging due to external force.

Furthermore, even when the laminate 10 for a battery outer package comes into contact with an electrolyte, it is possible to prevent the appearance of the battery from changing (such as discoloration).

Since the coating layer 16 is formed by coating, the laminated body 10 for a battery package can be formed thinner than in the case of laminating a resin film with an adhesive. This makes it possible to reduce the thickness of the battery packaging container 20.

In the laminated body 10 for battery packaging of the present invention, the use of SUS foil 12 can increase the mechanical strength (tensile strength, etc.), and therefore can reduce breakage and pin-holes when forming recesses by drawing occur.

In addition, since the SUS foil 12 having high mechanical strength is used, when transporting and assembling the secondary battery 40, the structure (cover, etc.) for protecting the secondary battery 40 is no longer necessary or can be simplified. As a result, the packaging cost can be reduced and the packaging device can be miniaturized. In addition, since the SUS foil with high mechanical strength is used, the thickness of the laminate for battery outer packaging can be reduced to increase the internal volume, and the battery volume efficiency can be improved.

Also, since the SUS foil 12 with the surface coating layer 17 is used, even if the electrolyte is decomposed by moisture immersed in the container 20 for battery outer packaging to generate acid, it is difficult to cause deterioration due to corrosion problem. Therefore, it is possible to prevent the leakage of the electrolytic solution due to the corrosion of the metal foil, the deterioration of the battery performance, and the ignition.

In the laminated body 10 for battery packaging, a surface covering layer 17 is formed on the side of the sealing layer 13 of the SUS foil 12, and when the sealing layer 13 has a multilayer structure, it has the aforementioned thermally adhesive polyolefin resin layer. , The sealing layer 13 and the SUS foil 12 can be bonded very firmly.

Therefore, when the concave portion is formed by drawing, it is possible to prevent the peeling between the sealing layer 13 and the SUS foil 12 while preventing the laminated body 10 for battery outer packaging from being broken. Accordingly, it is possible to reduce the occurrence of defects in the battery packaging container 20 during molding, improve the manufacturing yield of the secondary battery 40, and increase the production efficiency.

In addition, in the laminated body 10 for battery packaging, by increasing the adhesion strength between the sealing layer 13 and the SUS foil 12, it is possible to prevent water from infiltrating into the battery packaging container 20 from the outside. Therefore, it is possible to suppress the deterioration of the electrolyte over time, and extend the product life of the secondary battery 40.

FIG. 4 shows a laminate 50 for a battery outer package as a second embodiment of the laminate for a battery outer package of the present invention.

The laminated body 50 for battery packaging has a base layer 11 formed between the coating layer 16 and the printed layer 15 and an adhesive layer 14 formed between the printed layer 15 and the surface cover layer 18, which is different from FIG. 1 The laminated body 10 for battery packaging shown.

The base material layer 11 is not particularly limited as long as it has sufficient mechanical strength. For example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polyethylene terephthalate can be used. Polyester resins such as butylene glycol formate (PBT); polyamide resins such as nylon (Nylon); polyolefin resins such as stretched polypropylene (OPP); made of polyetheretherketone (PEEK) and polyphenylene sulfide Synthetic resin film composed of ether (PPS).

The base material layer 11 is preferably composed of a single-layer or multi-layer film of a heat-resistant resin film having a melting point of 200° C. or higher. Examples of such heat-resistant resin films include PET films, PEN films, PBT films, nylon films, PEEK films, and PPS films. However, PET films that are advantageous in terms of cost are particularly preferred.

The adhesive layer 14 is not particularly limited as long as the base material layer 11 and the SUS foil 12 can be adhered, for example, it can be formed by a polyurethane adhesive, an epoxy adhesive, or the like. The adhesive layer 14 can be formed by, for example, a dry lamination method.

In this laminate 50 for battery packaging, the base material layer 11 is formed of a heat-resistant resin film, and therefore, the durability of the secondary battery 40 can be further improved.

The embodiments of the present invention have been described above with reference to the drawings. However, the present invention is not limited to these embodiments, and various changes can be made without changing the gist of the present invention.

10‧‧‧Layer for battery packaging 11‧‧‧ Base layer 12‧‧‧SUS foil 13‧‧‧Sealing layer 14‧‧‧adhesive layer 15‧‧‧Printing layer (second coating layer) 16‧‧‧Coating layer (first coating layer) 17‧‧‧Surface coating 18‧‧‧Surface coating 20‧‧‧Battery packaging container 27‧‧‧Lithium ion battery 28‧‧‧Electrode lead 29‧‧‧Peripheral Department 30‧‧‧Container body 31‧‧‧recess 32‧‧‧Flange 33‧‧‧covering material 34‧‧‧Peripheral Department 40‧‧‧Secondary battery 50‧‧‧Layer for battery packaging 60‧‧‧Layer for battery packaging 70‧‧‧Layer for battery packaging 80‧‧‧Layer for battery packaging

[Fig. 1] is a schematic cross-sectional view of a first embodiment of a laminate for a non-aqueous battery package of the present invention. [FIG. 2] is a perspective view of an example of a secondary battery prepared using the laminate for nonaqueous battery outer packaging of FIG. 1. [FIGS. 3 a and b] are perspective views of the manufacturing process of the secondary battery of FIG. 2. [Fig. 4] is a schematic cross-sectional view of a second embodiment of the laminate for nonaqueous battery packaging of the present invention. [Fig. 5] is a schematic cross-sectional view of a first modification of the laminate for a battery outer package shown in Fig. 1. [Fig. 6] is a schematic cross-sectional view of a second modification of the laminate for a battery outer package shown in Fig. 1. [FIG. 7] is a schematic cross-sectional view of a third modification of the laminate for a battery outer package shown in FIG. 1.

10‧‧‧Layer for battery packaging

11‧‧‧ Base layer

12‧‧‧SUS foil

13‧‧‧Sealing layer

14‧‧‧The first adhesive layer

15‧‧‧Printing layer (second coating layer)

16‧‧‧Coating layer (first coating layer)

17‧‧‧Surface coating

18‧‧‧Surface coating

Claims (4)

A laminated body for nonaqueous battery outer packaging, comprising: a SUS foil and a sealing layer laminated; a surface covering layer with a thickness of 0.05 μm to 1.0 μm is formed on at least one side of the sealing layer of the SUS foil , The surface coating layer is made by drying and curing the water-soluble paint containing water-soluble resin, metal fluoride and organic chelating agent; the SUS foil has a coating layer on the side opposite to the sealing layer side , The coating layer is selected from polyurethane resin, acrylic resin, polyvinylidene chloride, vinylidene chloride-vinyl chloride copolymer resin, maleic anhydride modified polypropylene resin, polyester resin, epoxy resin, phenolic Resin group consisting of resin, phenoxy resin, fluororesin, cellulose ester resin, cellulose ether resin, polyamide resin, polyphenylene ether resin, polyphenylene sulfide resin, polyaryl ether resin, polyether ether ketone resin At least one resin is formed. The laminate for a nonaqueous battery outer package according to claim 1, wherein the coating layer is a thin-film cured layer formed by coating and drying a solvent-based paint, and the solvent-based paint dissolves the resin in Prepared in organic solvents. The laminate for a nonaqueous battery outer package according to claim 1 or 2, wherein the coating layer is colored with achromatic or colored color-forming agent. The laminate for a nonaqueous battery outer package according to claim 1 or 2, wherein the metal fluoride is a substance that cross-links the water-soluble resin and inactivates the surface of the SUS foil.

Images