JP6768362B2 - Battery exterior laminate, battery exterior laminate manufacturing method, battery exterior and battery - Google Patents

Description

The present invention relates to a battery exterior laminate that is good as an exterior body such as a secondary battery or a capacitor, a method for manufacturing the battery exterior laminate, a battery exterior body and a battery obtained by using the laminate.

Amid growing awareness of the environment, secondary batteries such as lithium-ion batteries and capacitors such as electric double layer capacitors are attracting attention as storage batteries for storing electrical energy as well as utilizing natural energy such as solar power and wind power. ing.
As the exterior body used for these batteries, a battery exterior laminate in which a metal foil and a resin layer are laminated is used for the purpose of miniaturization and weight reduction. Such a battery exterior laminate is formed by drawing or the like so as to form a tray having recesses to form an exterior container body.
Further, in the same manner as the outer body container main body, the battery outer laminate is molded to obtain the outer body lid portion. After storing the battery body in the recess of the exterior container body, the exterior body lid is overlapped so as to cover the stored battery body, and the side edges of the container body and the exterior body lid are adhered to form the exterior. You can get a battery in which the battery body is stored in the body.

For example, Patent Document 1 discloses a battery exterior laminate in which a base material layer, an aluminum foil, and an innermost layer made of polypropylene or polyethylene are laminated in this order.

Japanese Unexamined Patent Publication No. 2012-333393

As the application fields of batteries such as secondary batteries are expanding, the development of small batteries with large capacity is being promoted. Similarly, the laminate for battery exterior is also required to be thinned while maintaining excellent properties such as mechanical strength, water resistance, and chemical resistance (electrolyte resistance). In general, the mechanical strength, water resistance, chemical resistance (electrolyte resistance) and light-shielding property of the battery exterior laminate are mainly ensured by an inorganic layer such as a metal foil in the battery exterior laminate. ing. As the metal foil, an aluminum foil having excellent workability is widely used (see Patent Document 1).
However, since aluminum foil is superior in workability to other metal foils, it is possible to manufacture a laminate with a high yield, while mechanical strength such as piercing strength is higher than that of other metal foils. Is inferior. Therefore, in order to obtain mechanical strength, the thickness of the aluminum foil cannot be kept below a certain level, and in the present situation where the aluminum foil is used, it is difficult to make the thin film of the battery exterior laminate.

The present invention has been made in view of the above-mentioned current situation, and is a battery exterior laminate having excellent characteristics and capable of being manufactured with high yield and productivity, and can achieve thinning. It is an object of the present invention to provide a new battery exterior laminate.

As a result of repeated studies to achieve the above object, the present inventors have adopted a configuration in which a thin film can be formed while ensuring mechanical strength such as piercing strength by using stainless steel foil instead of aluminum foil. .. However, it was found that when the battery exterior was manufactured using a thin-film stainless steel foil, creases and wrinkles in a shape not seen in the past were formed, and this problem was studied diligently to complete the present invention.
Specifically, as a layer structure that can be dry-laminated, a structure using a base material layer containing polypropylene or polyethylene and a polyolefin adhesive layer having a relatively low melting point has been found, and according to this structure, broken wrinkles are found. The present invention has been completed by finding that it is possible to manufacture a laminate for a battery exterior without a coating material with high productivity.

That is, the present invention has adopted the following configuration.
A first aspect of the present invention is a laminate for battery exterior, which comprises at least a first base material layer, a first adhesive layer, a first corrosion prevention layer, a stainless steel foil, and a second base material layer in this order. The first base material layer is a layer containing polypropylene or polyethylene, the first adhesive layer is made of an adhesive containing polyolefin having a melting point of 50 to 100 ° C., and the thickness of the stainless steel foil is high. It is a laminate for battery exterior, which is characterized by having a thickness of 40 μm or less.
The first corrosion prevention layer is preferably a layer containing a water-soluble resin.
The second base material layer is a layer made of polyethylene terephthalate and having a thickness of 3 to 11 μm, and it is preferable to have a second adhesive layer between the second base material layer and the stainless steel foil. ..
The first adhesive layer is preferably a layer composed of an adhesive containing an acid-modified polyolefin resin having a melting point of 50 to 100 ° C. and a phenol novolac type epoxy resin.
The first corrosion prevention layer preferably contains a water-soluble resin, a metal halide compound, and a chelating agent.
A second aspect of the present invention is a method for manufacturing a battery exterior laminate, which comprises producing the battery exterior laminate according to the first aspect, wherein a first adhesive is formed on one side of a stainless steel foil. A method for producing a battery exterior laminate, which comprises a step of arranging the agent layer so as to be in contact with the first base material layer and dry-laminating the laminate at 70 to 150 ° C. ..
A third aspect of the present invention is a battery exterior body including the battery exterior laminate of the first aspect, which has an internal space for accommodating a battery and is a first base material layer of the battery exterior laminate. The battery exterior is characterized in that the side of the battery is the side of the internal space.
A fourth aspect of the present invention is a battery comprising the battery exterior body of the third aspect.

According to the present invention, it is possible to provide a battery exterior laminate having excellent characteristics and capable of being manufactured with high yield and productivity. Further, the battery exterior laminate of the present invention can be thinned.

It is schematic cross-sectional view which shows 1st Embodiment of the laminated body for battery exterior which concerns on this invention. It is a schematic process diagram which shows an example of the manufacturing method of the laminated body for battery exterior which concerns on this invention. It is a perspective view which shows an example of the secondary battery produced using the battery exterior laminated body which concerns on this invention. It is a perspective view which shows the process of manufacturing a secondary battery using the battery exterior laminated body which concerns on this invention. It is a perspective view which shows the process of manufacturing a secondary battery using the battery exterior laminated body which concerns on this invention.

Hereinafter, the present invention will be described based on preferred embodiments. It should be noted that the present embodiment describes the gist of the invention more specifically, but does not limit the present invention unless otherwise specified.

[Battery exterior laminate]
The battery exterior laminate (hereinafter, may be simply referred to as “laminate”) according to the first aspect of the present invention is at least a first base material layer, a first adhesive layer, a first corrosion prevention layer, and stainless steel. A laminate for battery exterior provided with a steel foil and a second base material layer in this order.
The first base material layer is a layer containing polypropylene or polyethylene.
The first adhesive layer comprises an adhesive containing a polyolefin having a melting point of 50 to 100 ° C.
The thickness of the stainless steel foil is 40 μm or less.

FIG. 1 is a cross-sectional view showing a schematic configuration of a battery exterior laminate 10 according to an embodiment of the present invention.
The laminate 10 according to the present embodiment includes a first base material layer 11, a first adhesive layer 12, a first corrosion prevention layer 13, a stainless steel foil 14, a second corrosion prevention layer 16, and a second. The adhesive layer 17 and the second base material layer 15 are provided in this order.
That is, the laminate 10 according to the present embodiment has the first corrosion prevention layer 13 and the second corrosion prevention layer 16 formed on both surfaces of the stainless steel foil 14, and the first adhesive layer on the first corrosion prevention layer 13. It has a seven-layer structure including a first base material layer 11 laminated via 12 and a second base material layer 15 laminated on a second corrosion prevention layer 16 via a second adhesive layer 17. ..
Hereinafter, each layer will be described in detail.

The first base material layer 11 is a layer containing polypropylene or polyethylene, and is preferably a homopolymer or block copolymer having propylene or ethylene because the adhesiveness to the first adhesive layer 12 is improved; polypropylene film. And / or a polyethylene film is more preferred; at least a polypropylene film is particularly preferred. By using these materials, it is possible to satisfactorily bond the first base material layer 11 and the stainless steel foil 14 having the first corrosion prevention layer 13 on the surface via the first adhesive layer 12. Become.
The first base material layer 11 may have a single-layer structure or a multi-layer structure. As an example of the first base material layer 11 having a multilayer structure, a two-layer film in which a polyethylene terephthalate (PET) resin film is laminated on a polypropylene film can be mentioned. The first base material layer 11 may have a multilayer structure in which three or more films are laminated. When the 11th base material layer has a multilayer structure, it is preferable that the layer containing polypropylene or polyethylene is arranged so as to be in contact with the first adhesive layer 12.

The melting point of the polypropylene film or polyethylene film used for the first base material layer 11 is not particularly limited as long as it has the heat resistance required for the battery exterior laminate 10.
The thickness of the first base material layer 11 can be, for example, 1 to 30 μm.

The first adhesive layer 12 is a layer made of an adhesive containing polyolefin having a melting point of 50 to 100 ° C.
Conventionally, laminating the metal foil and the base resin layer has been mainly performed by thermal laminating. When the surface of the base resin layer is melted at a high temperature by thermal lamination and fused with the metal foil, it is not necessary to provide an adhesive layer between the metal foil and the base resin layer, and the aging time of the adhesive layer is also increased. This is because it becomes unnecessary.
However, stainless steel foil, which has low thermal conductivity and is difficult to expand thermally, is less likely to propagate heat than other metal foils such as aluminum foil. Therefore, when high heat is applied to the stainless steel foil, distortion (curl) is likely to occur in the width direction of the stainless steel foil. When heat laminating is performed using such a stainless steel foil, heat is not sufficiently propagated in the plane, and some parts are not in contact with the thermocompression bonding rollers in the width direction, or they are not in contact with the rolls. , The strain itself may cause creases or wrinkles during thermocompression bonding. Further, when the stainless steel foil is heated to a high temperature at which distortion does not occur, the productivity may decrease due to a decrease in the processing speed or an increase in the required amount of heat.
Therefore, in the present invention, by providing a layer made of an adhesive containing polyolefin having a relatively low melting point of 50 to 100 ° C., the stainless steel foil is provided at a relatively low temperature such that distortion does not occur, that is, around 100 ° C. or At a temperature lower than that, the stainless steel foil having the first corrosion prevention layer and the first base material layer can be adhered to each other via the first adhesive layer. Examples of the bonding method at 100 ° C. or lower include dry laminating. By making it possible to bond by a relatively low temperature method such as dry laminating, it is possible not only to improve the yield due to breakage and wrinkles of the stainless steel foil, but also to shorten the time required for thermal laminating, which makes work efficiency. Also improves. Further, by providing the adhesive layer, the adhesiveness between the first base material layer and the stainless steel foil (having the first corrosion prevention layer) is improved as compared with the case where the base material resin is melted by thermal lamination. The strength of the entire laminate is increased, and the laminate is not damaged even when the laminate is exposed to chemicals such as an electrolytic solution or water.

For the first adhesive layer 12, for example, an adhesive containing a polyolefin having a melting point of 50 to 100 ° C. is applied onto the surface of the stainless steel foil 14 provided with the first corrosion prevention layer 13 and dried. Can be formed by
Hereinafter, "adhesive containing polyolefin having a melting point of 50 to 100 ° C." (hereinafter, may be simply referred to as "adhesive") will be described.

-Adhesive In the present invention, the adhesive forming the first adhesive layer 12 is not particularly limited as long as it contains a polyolefin having a melting point of 50 to 100 ° C., but among them, the acid-modified melting point 50 An adhesive containing a polyolefin resin at ~ 100 ° C. is preferable. By using the acid-modified polyolefin resin, it is possible to obtain a first adhesive layer 12 suitable for bonding the first base material layer 11 and the stainless steel foil 14 (having the first corrosion prevention layer 13).
Hereinafter, the "acid-modified polyolefin resin having a melting point of 50 to 100 ° C." may be simply referred to as "acid-modified polyolefin resin".

(Acid-modified polyolefin resin)
In the present invention, the acid-modified polyolefin resin is a polyolefin-based resin modified with an unsaturated carboxylic acid or a derivative thereof, and the polyolefin-based resin has an acid functional group such as a carboxy group or an anhydrous carboxylic acid group. Is.
The acid-modified polyolefin resin can be obtained by modifying a polyolefin-based resin with an unsaturated carboxylic acid or a derivative thereof, or copolymerizing an acid-functional group-containing monomer with olefins.
Among them, as the acid-modified polyolefin resin, those obtained by acid-modifying a polyolefin-based resin are preferable.
Examples of the acid modification method include graft modification in which a polyolefin resin and an acid functional group-containing monomer are melt-kneaded in the presence of a radical polymerization initiator such as an organic peroxide or an aliphatic azo compound.

Examples of the polyolefin-based resin include polyethylene, polypropylene, poly-1-butene, polyisobutylene, a random copolymer of propylene and ethylene or α-olefin, and a block copolymer of propylene and ethylene or α-olefin. .. Among them, homopolypropylene (propylene homopolymer; hereinafter, sometimes referred to as “homo PP”), propylene-ethylene block copolymer (hereinafter, sometimes referred to as “block PP”), propylene-ethylene. Polypropylene-based resins such as Random Copolymer (hereinafter, may be referred to as "Random PP") are preferable, and Random PP is particularly preferable.
Examples of the olefins in the case of copolymerization include olefin-based monomers such as ethylene, propylene, 1-butene, isobutylene, 1-hexene and α-olefin.

The acid functional group-containing monomer is a compound having an ethylenic double bond and a carboxy group or a carboxylic acid anhydride group in the same molecule, and is an acid of various unsaturated monocarboxylic acids, dicarboxylic acids, or dicarboxylic acids. An anhydride is mentioned.
Examples of the acid functional group-containing monomer having a carboxy group (carboxy group-containing monomer) include acrylic acid, methacrylic acid, maleic acid, nadic acid, fumaric acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, tetrahydrophthalic acid, and endo. Examples thereof include α, β-unsaturated carboxylic acid monomers such as −bicyclo [2.2.1] -5-heptene-2,3-dicarboxylic acid (endic acid).
Examples of the acid functional group-containing monomer having a carboxylic acid anhydride group (carboxylic acid anhydride group-containing monomer) include unsaturated dicarboxylic acids such as maleic anhydride, nadicic anhydride, itaconic anhydride, citraconic anhydride, and endic anhydride. Anhydride monomer can be mentioned.
As these acid functional group-containing monomers, one type may be used alone or two or more types may be used in combination in the acid-modified polyolefin resin.

Among them, as the acid functional group-containing monomer, an acid functional group-containing monomer having an acid anhydride group is preferable, a carboxylic acid anhydride group-containing monomer is more preferable, and maleic anhydride is preferable because of its high reactivity with an epoxy resin described later. Is particularly preferable.
When some of the acid functional group-containing monomers used for acid modification were unreacted, the unreacted acid functional group-containing monomers were removed in advance in order to prevent the unreacted acid functional group-containing monomers from reducing the adhesive strength. It is preferable to use the one as an acid-modified polyolefin resin.

In the acid-modified polyolefin resin, the component derived from the polyolefin-based resin or olefins is preferably 50 parts by mass or more with respect to 100 parts by mass of the total amount of the acid-modified polyolefin resin.

The melting point of the acid-modified polyolefin resin is 50 to 100 ° C, preferably 80 ° C to 100 ° C. By using an acid-modified polyolefin resin having such a melting point, the softening temperature (melting point) of the first adhesive layer 12 itself can be lowered, and at a lower temperature, the first base material layer 11 and (first corrosion prevention) can be lowered. It can be adhered to the stainless steel foil 14 (having the layer 13).

Among them, as the acid-modified polyolefin resin, maleic anhydride-modified polypropylene is preferable from the viewpoint of adhesiveness and an appropriate melting point. By using polypropylene that is soluble in an organic solvent, it becomes suitable for forming the first adhesive layer 12 used for dry lamination.

The adhesive in the present invention may further contain an additive compound in addition to the acid-modified polyolefin resin. Examples of the additive compound include a resin having an epoxy group (hereinafter, referred to as “epoxy resin”). By containing the epoxy resin, the crosslinked structure formed by the adhesive becomes more dense, and the adhesiveness of the first adhesive layer 12 is further improved.

(Epoxy resin)
The epoxy resin is not particularly limited as long as it is a compound having two or more epoxy groups in one molecule. For example, a phenoxy resin synthesized from bisphenols and epichlorohydrin; a phenol novolac type epoxy resin; a bisphenol type epoxy resin, etc. Can be mentioned. Among them, it is preferable to use a phenol novolac type epoxy resin because the epoxy content per molecule is high and a particularly dense crosslinked structure can be formed.

In the present invention, the phenol novolac type epoxy resin is a compound having a basic structure of a phenol novolac resin obtained by acid condensation of phenol and formaldehyde, and an epoxy group introduced into a part of the structure. The amount of epoxy group introduced per molecule in the phenol novolac type epoxy resin is not particularly limited, but by reacting an epoxy group raw material such as epichlorohydrin with the phenol novolac resin, a large number of phenols present in the phenol novolac resin are present. Since a large number of epoxy groups are introduced into the phenolic hydroxyl group, it is usually a polyfunctional epoxy resin.

Among them, as the phenol novolac type epoxy resin, a bisphenol A novolac type epoxy resin having a phenol novolac structure as a basic skeleton and also having a bisphenol A structure is preferable. The bisphenol A structure in the epoxy resin may be any structure that can be derived from bisphenol A, and the hydroxyl groups at both ends of the bisphenol A may be substituted with a group such as an epoxy group-containing group.
An example of the bisphenol A novolak type epoxy resin is a resin represented by the following general formula (1).

［式（１）中、Ｒ^１〜Ｒ^６はそれぞれ独立に水素原子又はメチル基であり、ｎは０〜１０の整数であり、Ｒ^Ｘはエポキシ基を有する基である。］

In Expression ^(1), R 1 ~R ⁶ are each independently a hydrogen atom or a methyl group, n is an integer of 0, ^{R X} is a group having an epoxy group. ]

In formula (1), R ^{1 to} R ⁶ are independently hydrogen atoms or methyl groups, respectively. When n is an integer of 2 or more, R ³ and R ⁴ may be the same or different, respectively.
The resin represented by the formula (1) preferably satisfies at least one of the following (i) to (iii).
(I) Both R ¹ and R ² are methyl groups, (ii) both R ³ and R ⁴ are methyl groups, and both (iii) R ⁵ and R ⁶ are methyl groups, for example, satisfying (i) above. Therefore, in the formula (1), the carbon atom to which R ¹ and R ² are bonded and the ^two hydroxyphenyl groups to which the carbon atom is bonded form a structure derived from bisphenol A.

In formula (1), ^RX is a group having an epoxy group. Examples of the group having an epoxy group include an epoxy group and a combination of an epoxy group and an alkylene group, and a glycidyl group is preferable.

The epoxy equivalent of the bisphenol A novolak type epoxy resin is preferably 100 to 300, and more preferably 200 to 300. The epoxy equivalent (g / eq) is the molecular weight of the epoxy resin per epoxy group, and the smaller this value is, the more epoxy groups are in the resin. By using an epoxy resin having a relatively small epoxy equivalent, the adhesiveness between the epoxy resin and the adherend is good even when the amount of the epoxy resin added is relatively small, and the epoxy resin and the acid modification are made. It is sufficiently cross-linked with the polyolefin resin.

Examples of such bisphenol A novolak type epoxy resin include jER154, jER157S70, and jER-157S65 manufactured by Mitsubishi Chemical Corporation; EPICLON manufactured by DIC Corporation.
Commercially available products such as N-730A, EPICLON N-740, EPICLON N-770, and EPICLON N-775 (all of which are trade names) can also be used.

By using the epoxy resin as described above, both the acid functional group of the acid-modified polyolefin resin and the epoxy group of the epoxy resin have adhesiveness to the adherend (particularly the functional group such as the hydroxyl group of the adherend). By functioning as a functional group, it is considered possible to exhibit excellent adhesiveness to the first base material layer 11 and the stainless steel foil 14 (having the first corrosion prevention layer 13).
In addition, a part of the acid functional group of the acid-modified polyolefin resin reacts with a part of the epoxy group of the epoxy resin to form a crosslinked structure of the acid-modified polyolefin resin and the epoxy resin, and this crosslinked structure reinforces the strength of the resin. It is considered that good durability as well as excellent adhesiveness can be obtained.

The adhesive used in the present invention preferably contains 1 to 20 parts by mass of epoxy resin with respect to 100 parts by mass of acid-modified polyolefin resin, and 5 to 20 parts by mass of epoxy resin with respect to 100 parts by mass of acid-modified polyolefin resin. 10 parts by mass is more preferable, and 5 to 7 parts by mass of the epoxy resin is particularly preferable with respect to 100 parts by mass of the acid-modified polyolefin resin.
The adhesive used in the present invention can further appropriately contain miscible additives, additional resins, plasticizers, stabilizers, colorants and the like, if desired.

Further, the adhesive of the present invention may or may not contain an organic solvent.
By containing an organic solvent to prepare a liquid adhesive, for example, an adhesive suitable for dry lamination can be obtained. An adhesive layer can be formed by applying and drying such a liquid adhesive on a layer to be a lower layer, and adhesion can be achieved by dry laminating.
On the other hand, when the organic solvent is not contained, an adhesive layer suitable for thermal lamination or the like can be formed by melt-kneading the acid-modified polyolefin resin and the epoxy resin and then extruding or the like.
When an organic solvent is contained, the organic solvent used is not particularly limited as long as it can suitably dissolve the above-mentioned resin, and for example, toluene or the like can be used. The amount of the organic solvent used is not particularly limited, but the solid content is preferably 3 to 30% by mass, more preferably 5 to 25% by mass, still more preferably 10 to 20% by mass.

The thickness of the first adhesive layer 12 can be, for example, 0.5 to 10 μm. By setting the thickness within this range, the first base material layer 11 and the stainless steel foil 14 can be adhered with a high adhesive force, and delamination can be prevented.

In this embodiment, the first corrosion prevention layer 13 is a layer formed for surface modification of the stainless steel foil 14, and is a layer for preventing corrosion of the stainless steel foil 14 due to rust or the like.
The first corrosion prevention layer 13 in this embodiment is formed by applying a water-soluble paint containing a water-soluble resin, a metal halide compound, and a chelating agent, and then drying and curing the coating.

・ Water-soluble paint (water-soluble resin)
As the water-soluble resin, it is preferable to use one or more of a polyvinyl alcohol-based resin and a polyvinyl ether-based resin.
The polyvinyl alcohol-based resin is at least one water-soluble resin selected from a polyvinyl alcohol resin and a modified polyvinyl alcohol resin.
The polyvinyl alcohol-based resin can be produced, for example, by saponifying a polymer of a vinyl ester-based monomer or a copolymer thereof.
As the polymer of the vinyl ester-based monomer or its copolymer, a homopolymer of a fatty acid vinyl ester such as vinyl formate, vinyl acetate, vinyl butyrate, or a homopolymer of a vinyl ester-based monomer such as an aromatic vinyl ester such as vinyl benzoate, or Examples thereof include a copolymer and a copolymer of another monomer copolymerizable therewith.
Other copolymerizable monomers include, for example, olefins such as ethylene and propylene, ether group-containing monomers such as alkyl vinyl ether, carbonyl groups such as diacetone acrylamide, diacetone (meth) acrylate, allyl acetoacetate, and acetoacetate ester. Examples thereof include (ketone group) -containing monomers, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and maleic anhydride, vinyl halides such as vinyl chloride and vinylidene chloride, and unsaturated sulfonic acids.
The degree of saponification of the polyvinyl alcohol-based resin is usually preferably 90 to 100 mol%, more preferably 95 mol% or more.
Examples of the polyvinyl alcohol-based resin include alkyl ether-modified polyvinyl alcohol resin, carbonyl-modified polyvinyl alcohol resin, acetoacetyl-modified polyvinyl alcohol resin, acetoamide-modified polyvinyl alcohol resin, acrylic nitrile-modified polyvinyl alcohol resin, carboxyl-modified polyvinyl alcohol resin, and silicone-modified polyvinyl alcohol. Examples thereof include resins and ethylene-modified polyvinyl alcohol resins. Among them, alkyl ether-modified polyvinyl alcohol resin, carbonyl-modified polyvinyl alcohol resin, carboxyl-modified polyvinyl alcohol resin, and acetoacetyl-modified polyvinyl alcohol resin are preferable.
Commercially available polyvinyl alcohol-based resins include, for example, J-Poval DF-20 (trade name) manufactured by Japan Vam & Poval Co., Ltd. and Crosmer H series manufactured by Nippon Carbide Industries Co., Ltd. ( Product name) and so on. As the polyvinyl alcohol-based resin, one kind or a mixture of two or more kinds may be used.

Examples of the polyvinyl ether-based resin include ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexyl vinyl ether, norbornyl vinyl ether, allyl vinyl ether, norbornenyl vinyl ether and 2-hydroxy. Examples thereof include homopolymers or copolymers of aliphatic vinyl ethers such as ethyl vinyl ether and diethylene glycol monovinyl ether, and copolymers of other monomers copolymerizable therewith. Examples of the other monomer copolymerizable with the vinyl ether-based monomer include those similar to the other monomers copolymerizable with the vinyl ester-based monomer described above.
In particular, polyvinyl ether-based resins containing an aliphatic vinyl ether having a hydroxyl group as a monomer, such as 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 2-hydroxypropyl vinyl ether, and monovinyl ethers of various glycols and polyhydric alcohols, are water-soluble. It can be suitably used in the present invention because it has a cross-linking reaction with respect to a hydroxyl group.
Since the vinyl ether monomer can be used in the resin production (polymerization) step, these polyvinyl ether-based resins undergo a saponification treatment unlike the polyvinyl alcohol-based resins produced via the vinyl ester-based polymer. It can be manufactured without any. Further, a copolymer containing a vinyl ester-based monomer and a vinyl ether-based monomer, or a vinyl alcohol-vinyl ether copolymer obtained by saponifying the copolymer can also be used. A mixture of a polyvinyl alcohol-based resin other than the polyvinyl ether-based resin and a polyvinyl ether-based resin can also be used.

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

(Metal halide compound)
The metal halide compound is preferably water-soluble because it needs to be mixed with the above-mentioned water-soluble resin.
Examples of the metal halide compound include chromium halide, iron halide, zirconium halide, titanium halide, hafnium halide, hydrohydrogenate titanium halide, and salts thereof. Examples of the halogen atom include chlorine, bromine and fluorine, and chlorine or fluorine is preferable. Further, fluorine is particularly preferable.
Among them, as the metal halide compound, chlorides or fluorides of iron, chromium, manganese or zirconium are preferable.
The metal halide compound has an action of improving chemical resistance such as electrolytic solution resistance. That is, the surface of the stainless steel foil 14 can be passivated and the corrosion resistance to the electrolytic solution can be improved. The metal halide compound also has an action of cross-linking the water-soluble resin.

(Chelating agent)
Water-soluble paints contain chelating agents. The chelating agent is a material capable of forming a metal ion complex by coordinating with a metal ion.
The chelating agent binds a metal compound (chromium oxide or the like) derived from the metal halide compound to the water-soluble resin to increase the compressive strength of the first corrosion prevention layer 13, so that the first corrosion prevention layer 13 has a chelating agent. Even when the thickness exceeds, for example, 0.2 μm and is 1.0 μm or less, the first corrosion prevention layer 13 does not become brittle and crack or peel off. Therefore, the adhesive strength between the stainless steel foil 14 and the first adhesive layer 12 and the adhesive strength between the stainless steel foil 14 and the layer on the upper layer side thereof can be increased.
Further, the chelating agent has an action of making the water-soluble resin water-resistant by chemically reacting with the water-soluble resin or the metal halide compound.

As the chelating agent, for example, an aminocarboxylic acid-based chelating agent, a phosphonic acid-based chelating agent, an oxycarboxylic acid-based chelating agent, and a (poly) phosphoric acid-based chelating agent can be used.

Examples of the aminocarboxylic acid-based chelating agent include nitrilotriacetic acid (NTA), hydroxyethyliminodiacetic acid (HIDA), ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), diethylenetriaminetetraacetic acid (DTPA), and the like. Triethylenetetraminetetraacetic acid (TTHA), transcyclohexanediaminetetraacetic acid (CyDTA), 1,2-propanediaminetetraacetic acid (1,2-PDTA), 1,3-propanediaminetetraacetic acid (1,3-PDTA), 1,4-Butandiaminetetraacetic acid (1,4-BDTA), 1,3-diamino-2-hydroxypropanetetraacetic acid (DPTA-OH), glycol etherdiaminetetraacetic acid (GEDTA), ethylenediamine orthohydroxyphenylacetic acid (EDHPA) ), SS-Ethylenediaminediaminediaminedic acid (SS-EDDS), ethylenediaminediaminediaminedicic acid (EDDS), β-alanine diacetic acid (ADA), methylglycine diacetic acid (MGDA), L-aspartic acid-N, N-diacetate. (ASDA), L-glutamic acid-N, N-diacetic acid (GLDA), N, N'-bis (2-hydroxybenzyl) ethylenediamine-N, N'-diacetic acid (HBEDDA) can be mentioned.

The phosphonic acid-based chelating agent is not particularly limited as long as it is a compound having a −P (= O) (OH) ₂ structure derived from phosphonic acid (HP (= O) (OH) ₂ ), and is, for example, N. , N, N-trimethylenphosphonic acid (NTMP), 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), ethylenediamine-N, N, N', N'-tetramethylenephosphonic acid (EDTMP), diethylenetriaminepenta Methylenephosphonic acid (DTPMP), 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC), nitrilotris (methylenephosphonic acid) (NTMP), and the like.

Examples of the oxycarboxylic acid-based chelating agent include glycolic acid, citric acid, malic acid, gluconic acid, and glucoheptonic acid.

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

Commercially available chelating agents include, for example, aminocarboxylic acid chelating agents such as Kirest PD-4H (PDTA); Kirest PH-540 (EDTMP), Kirest PH-210 (HEDP), Kirest PH-320. (NTMP), phosphonic acid-based chelating agents such as Kirest PH-430 (PBTC) (all of which are chelating agents manufactured by Kirest Co., Ltd., and the notation is a trade name) can be mentioned.

Among them, as the chelating agent, a phosphoric acid-based chelating agent (phosphoric acid compound) such as a phosphonic acid-based chelating agent and a (poly) phosphoric acid-based chelating agent is preferable, and a phosphonic acid-based chelating agent is more preferable.

The water-soluble resin is preferably 3 to 30% by mass, more preferably 5 to 20% by mass, still more preferably 10 to 15% by mass, based on the total solid content of the water-soluble coating material. Further, the metal halide compound is preferably 20 to 60% by mass, more preferably 30 to 55% by mass, and further preferably 40 to 50% by mass in the total solid content of the water-soluble coating material. The chelating agent is preferably 20 to 60% by mass, more preferably 30 to 50% by mass, still more preferably 35 to 45% by mass, based on the total solid content of the water-soluble coating material.

The water-soluble coating material can be produced by dissolving a water-soluble resin, a metal halide compound, and a chelating agent in a solvent containing water. Water is preferable as the solvent.
The solid content concentration in the water-soluble paint can be appropriately determined in consideration of the coatability of the first corrosion prevention layer 13 and the like, but is generally 0.1 to 10% by mass.

The thickness of the first corrosion prevention layer 13 is preferably 0.05 μm or more, more preferably more than 0.1 μm. By setting the thickness of the first corrosion prevention layer 13 to 0.05 μm or more, sufficient corrosion resistance is given to the battery exterior laminate 10, and the adhesive strength between the stainless steel foil 14 and the first adhesive layer 12 is provided. , And the adhesive strength between the stainless steel foil 14 and the first base material layer 11 can be increased.
The thickness of the first corrosion prevention layer 13 is preferably 1.0 μm or less, more preferably 0.5 μm or less. By setting the thickness of the first corrosion prevention layer 13 to 1.0 μm or less, the adhesive strength between the stainless steel foil 14 and the first adhesive layer 12 can be increased, and the material cost can be suppressed.

The stainless steel foil 14 is a metal foil made of stainless steel, and is made of, for example, stainless steel such as austenite, ferritic, and martensitic. The austenitic stainless steel includes SUS304, 316, 301 and the like, the ferrite type includes SUS430 and the like, and the martensitic stainless steel includes SUS410 and the like.

Since the stainless steel foil 14 has higher mechanical strength such as piercing strength and tensile strength than other metal foils such as aluminum foil, it can be used as a laminate 10 for battery exterior even when used with a thickness of 40 μm or less. Sufficient mechanical strength can be imparted. As a result, the stainless steel foil 14 and the laminate 10 as a whole can be thinned.
Further, due to the high mechanical strength, it is possible to reduce the occurrence of pinholes when forming recesses by drawing molding, and as a result, leakage of the contents sealed by the laminate (for example, leakage of battery liquid). Can be reduced. In addition, since the stainless steel foil 14 is superior in corrosion resistance to other metal foils, it is possible to satisfactorily prevent deterioration due to corrosion.

The thickness of the stainless steel foil 14 is 40 μm or less, preferably 5 to 40 μm, more preferably 5 to 30 μm, and particularly preferably 10 to 20 μm. By setting the value to the above lower limit or more, sufficient mechanical strength can be given to the battery exterior laminate 10 and the durability of the battery can be enhanced when used for a battery such as a secondary battery. Further, by setting the thickness of the stainless steel foil 14 to 40 μm or less, the battery exterior laminate 10 can be made sufficiently thin, and sufficient drawing workability can be provided.

The second corrosion prevention layer 16 has the same structure as the first corrosion prevention layer 13.

The second adhesive layer 17 may have the same structure as the first adhesive layer 12, or may be a layer made of an adhesive such as a general urethane-based adhesive or an epoxy-based adhesive. The thickness of the second adhesive layer 17 can be, for example, 0.5 to 10 μm. By setting the thickness within this range, the second base material layer 15 and the stainless steel foil 14 can be adhered with a high adhesive force, and delamination can be prevented.

The second base material layer 15 is not particularly limited as long as it has sufficient mechanical strength, and is, for example, a polyester resin such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT); A polyamide resin such as nylon (Ny); a polyolefin resin such as stretched polypropylene (OPP); a synthetic resin film made of polyetheretherketone (PEEK), polyphenylene sulfide (PPS), or the like can be used. Of these, PET film is preferable.
The thickness of the second base material layer 15 can be, for example, 1 to 50 μm, preferably 1 to 30 μm, and even more preferably 3 to 11 μm.

The second base material layer 15 may have a single-layer structure or a multi-layer structure. As an example of the second base material layer 15 having a multilayer structure, a bilayer film in which a polyethylene terephthalate (PET) resin film is laminated on a biaxially stretched polyamide resin film (ONy) can be mentioned. The second base material layer 15 may have a multilayer structure in which three or more films are laminated.
Further, in the embodiment shown in FIG. 1, the second base material layer 15 is the outermost layer. Therefore, the second base material layer may have a desired color and design by containing a colorant such as a pigment in addition to the resin.

The second base material layer 15 is preferably made of a single-layer or multi-layer film using a heat-resistant resin film having a melting point of 200 ° C. or higher. Examples of such a heat-resistant resin film include PET film, PEN film, PBT film, nylon film, PEEK film, PPS film and the like, and PET film which is advantageous in terms of cost is particularly preferable. By using such a heat-resistant resin film, the heat resistance of the battery exterior laminate 10 can be enhanced, and the durability of the battery in which the battery exterior laminate 10 is used can be improved.

In the battery exterior laminate 10 shown in FIG. 1, the first corrosion prevention layer 13 and the second corrosion prevention layer 16 are formed on both sides of the stainless steel foil 14, but the battery using the battery exterior laminate 10 is used. In the outer body, it is the inner surface side, and it is the first base material layer 11 side that can come into contact with the electrolytic solution or the like. Therefore, the corrosion prevention layer may be formed at least on the first base material layer 11 side of the stainless steel foil 14. That is, it is also possible to omit the second corrosion prevention layer 16 from the battery exterior laminate 10 of FIG. 1.

In the battery exterior laminate 10 shown in FIG. 1, the second base material layer 15 is the outermost layer, but a coating layer can also be formed on the outer surface side of the second base material layer 15.
The coating layer (first coating layer) is urethane resin, acrylic resin, polyvinylidene chloride, vinylidene chloride-vinyl chloride copolymer resin, maleic anhydride-modified polypropylene resin, polyester resin, epoxy resin, phenol resin, phenoxy resin, fluororesin. , Cellulosic ester resin, cellulose ether resin, polyamide resin, polyvinylidene ether resin (PPE), polyvinylidene sulfide resin (PPS), polyarylether resin (PAE), polyetheretherketone resin (PEEK). It is made of at least one resin. The coating layer is preferably made of a material having excellent heat resistance. These resins may be used alone or in combination of two or more.
The coating layer is preferably a thin film cured layer formed by applying and drying a solvent-based paint prepared by dissolving the resin in a general organic solvent.
By forming the coating layer, the insulating property of the battery exterior laminate 10 can be enhanced, and the surface of the battery exterior laminate 10 can be prevented from being scratched. Further, even when the battery exterior laminate 10 comes into contact with the electrolytic solution, it is possible to prevent a change in appearance (discoloration or the like).
Further, the coating layer can be colored by adding a colorant or a pigment to the solvent-based paint that forms the coating layer. In addition, the coating layer can be colored or printed so as to display characters, figures, images, patterns, etc. to enhance the design.
The thickness of the coating layer can be, for example, 0.1 to 20 μm, preferably 2 to 10 μm.

In the battery exterior laminate 10 shown in FIG. 1, the second base material layer 15 and the second adhesive layer 17 are in direct contact with each other, but in order to enhance the design on the inner surface side of the second base material layer 15. It is also possible to provide a printing layer of.
The print layer can have the same structure as the coating layer described above.

The thickness of the battery exterior laminate 10 is preferably 10 to 500 μm, more preferably 20 to 200 μm, and even more preferably 30 to 100 μm.

Examples of the battery in which the battery exterior laminate 10 is used include those using an organic electrolyte as the electrolytic solution, such as a secondary battery such as a lithium ion battery which is a secondary battery, and a capacitor such as an electric double layer capacitor. .. The organic electrolyte is generally one in which carbonate esters such as propylene carbonate (PC), diethyl carbonate (DEC), and ethylene carbonate are used as a medium, but the organic electrolyte is not particularly limited thereto.

[Manufacturing method of battery exterior laminate]
The method for manufacturing the battery exterior laminate of the second aspect of the present invention (hereinafter, may be simply referred to as “manufacturing method”) is the method for producing the battery exterior laminate of the first aspect, for example. , Manufactured by arranging the first adhesive layer formed on one side of the stainless steel foil so as to be in contact with the first base material layer, and dry laminating the laminate at 70 to 150 ° C. can do.
More specifically, for example, a step of forming a first corrosion prevention layer on one side of a stainless steel foil, a step of forming a first adhesive layer on the formed first corrosion prevention layer, and a first base material. It can be produced by a method having a step of arranging the layer and the formed first adhesive layer in contact with each other and dry-laminating the laminate at 70 to 150 ° C.
The details will be described below.

First, as shown in FIG. 2A, the first corrosion prevention layer 13 is formed on one side of the stainless steel foil 14.
Specifically, the water-soluble paint as described above is applied to the surface of the stainless steel foil 14, and then heat-dried. At this time, only the first corrosion prevention layer 13 may be formed by applying the water-soluble paint to only one side of the stainless steel foil 14, and as shown in FIG. 2A, both sides of the stainless steel foil 14 may be formed. The second corrosion prevention layer 16 may be formed at the same time by applying the water-soluble paint. When the second corrosion prevention layer 16 is provided, the second corrosion prevention layer 16 is preferably formed at a stage before the formation of the first adhesive layer 12 and the like, and at the same time as the first corrosion prevention layer 13. It is more preferable to be formed.
When the first corrosion prevention layer 13 and the second corrosion prevention layer 16 are formed at the same time, the stainless steel foil 14 is immersed in a water-soluble paint to adhere the water-soluble paint to both sides of the stainless steel foil 14, and then. It is also preferable to heat-dry.

Next, as shown in FIG. 2B, the first adhesive layer 12 is formed on the first corrosion prevention layer 13.
Specifically, a layer made of the adhesive as described above is formed on the surface of the stainless steel foil 14 provided with the first corrosion prevention layer 13, and if necessary, it is heated and dried. For example, a polyolefin resin and an epoxy resin contained if necessary are dissolved in an organic solvent, and then this solution is applied onto the first corrosion prevention layer 13 and dried to obtain a first adhesive. Layer 12 is formed. Further, the formation of the first adhesive layer 12 may be carried out as a series of steps using a known dry laminator or the like together with the step of FIG. 2C described later.

Then, as shown in FIG. 2C, the first base material layer 11 and the formed first adhesive layer 12 are arranged so as to be in contact with each other, and the laminate is dry-laminated at 70 to 150 ° C. ..
Specifically, a film constituting the first base material layer 11 is prepared in advance, the film is arranged on the first adhesive layer, and then dry lamination is performed. The temperature of the dry laminate is not particularly limited as long as it is a temperature at which the first base material layer 11, the first corrosion prevention layer 13, and the stainless steel foil 14 are satisfactorily adhered to each other via the first adhesive layer. However, it can be determined in consideration of the material and melting point of the adhesive constituting the first adhesive layer 12. The temperature at the time of dry laminating is generally 70 to 150 ° C, preferably 80 to 120 ° C. The pressure at the time of dry lamination is preferably 0.1 to 0.5 MPa.
In the manufacturing method of this embodiment, since the first base material layer 11, the first corrosion prevention layer 13, and the stainless steel foil 14 are bonded via the first adhesive layer 12, a dry laminate is adopted at the time of bonding. It becomes possible to do. Then, by adopting a dry laminate instead of the conventional thermal laminate that requires heating of more than 200 ° C. at the time of laminating, the temperature at the time of laminating can be significantly reduced. As a result, it is not necessary to consider breakage and wrinkles during thermocompression bonding due to distortion when high heat is applied to the stainless steel foil, and it is possible to use a stainless steel foil having excellent strength as the metal foil. In addition, since it is less likely to break or wrinkle during thermocompression bonding, the yield is improved by adopting a dry laminate that does not require a high temperature like a thermal laminate.

The step of forming the first adhesive layer 12 and the step of arranging the first base material layer 11 for dry laminating may be performed using a known dry laminating apparatus as a series of steps.

The method for forming the second corrosion prevention layer 16, the second adhesive layer 17, and the second base material layer 15 is not particularly limited, but for example, as shown in FIG. 2D, the second base material is previously formed. A second adhesive layer 17 is formed on the layer 15 to form a laminated body composed of two layers. Then, the two-layer laminate and the laminate having the first base material layer 11, the first adhesive layer 12, the first corrosion prevention layer 13, the stainless steel foil 14, and the second corrosion prevention layer 16 are secondly combined. By dry laminating the adhesive layer 17 and the second corrosion prevention layer 16 so as to be in contact with each other, the battery exterior laminate 10 composed of seven layers can be manufactured.

Although one embodiment of the first and second aspects of the present invention has been described above based on the battery exterior laminate 10 shown in FIGS. 1 and 2, the technical scope of the present invention is limited to the above-described embodiment. It is possible to make various changes without departing from the spirit of the present invention.
For example, the second corrosion prevention layer 16 may not be provided and may have a six-layer structure.
Further, another layer is provided on the side of the first base material layer 11 that does not come into contact with the first adhesive layer 12 or the side of the second base material layer 15 that does not come into contact with the second adhesive layer 17, and seven layers or It may be composed of eight or more layers.

[Battery exterior]
The battery exterior body of the third aspect of the present invention is a battery exterior body including the battery exterior laminate of the first aspect, has an internal space for accommodating the battery, and is the first of the battery exterior laminates. The battery exterior is such that the base material layer side is the side of the internal space. Specifically, it is obtained by molding the battery exterior laminate of the first aspect into a desired shape so that the first base material layer faces the internal space, and sealing the ends as necessary. It is a thing.
The shape, size, etc. of the battery outer body are not particularly limited, and can be appropriately determined according to the type of battery used.
The battery exterior may be composed of one member, or may be formed by combining two or more members (for example, a container body and a lid) as described later with reference to FIG. Good.

[battery]
The battery of the fourth aspect of the present invention includes the battery exterior of the third aspect.
Examples of the battery include a secondary battery such as a lithium ion battery which is a secondary battery, a capacitor such as an electric double layer capacitor, and the like using an organic electrolyte as an electrolytic solution.
As an example, a perspective view of the secondary battery 40 is shown in FIG. The secondary battery 40 is a battery outer container 20 containing a lithium ion battery 27.
In the battery exterior container 20, the container body 30 made of the battery exterior laminate 10 of the first aspect of the present invention and the lid portion 33 made of the battery exterior laminate 10 are overlapped, and the peripheral edge portion 29 is heat-sealed. It is formed by. Reference numeral 28 is an electrode lead connected to the positive electrode and the negative electrode of the lithium ion battery 27.

The battery shown in FIG. 3 can be manufactured as follows.
First, as shown in FIG. 4A, the battery exterior laminate 10 is molded by drawing or the like so as to form a tray having recesses 31 to obtain a container body 30. The depth of the recess 31 can be, for example, 2 mm or more.
A lithium ion battery (lithium ion battery 27 in FIG. 3) is housed in the recess 31 of the container body 30.
Next, as shown in FIG. 4B, the lid portion 33 made of the battery exterior laminate 10 is superposed on the container body 30, and the flange portion 32 of the container body 30 and the peripheral edge portion 34 of the lid portion 33 are heat-sealed. By doing so, the secondary battery 40 shown in FIG. 3 can be obtained. That is, in the battery shown in FIG. 3, the upper surface of the container body 30 is covered with the lid portion 33, so that the recess 31 and the lid portion 33 form an internal space for accommodating the battery.

Further, the battery in the present invention can also be manufactured as follows.
First, as shown in FIG. 5A, a part of the rectangular battery exterior laminate 50 on one end side in the longitudinal direction is pressed from the side of the first base material layer of the battery exterior laminate 50 by drawing molding or the like. To obtain a molded body 55 having a recess 51. The depth of the recess 51 can be, for example, 2 mm or more.
Next, although not shown, the lithium ion battery (lithium ion battery 27 in FIG. 2) is housed in the recess 51 of the molded body 55.

Next, the portion of the other end side of the molded body 55 where the recess 51 is not formed is bent toward the first base material layer so as to form a bending line L extending in the lateral direction of the molded body 55. .. Here, in the molded body 55, the region on the recess 51 side with respect to the bending line L is referred to as "first region 551", and the region on the side opposite to the recess 51 with respect to the bending line L is referred to as "second region 552".

Next, the first base material layer around the recess 51 in the first region 551 and the first base material layer (peripheral portion 54) overlapping the circumference 52 in the second region 552 are overlapped. As a result, the second region 552 overlaps the recess 51 of the first region 551.

Next, as shown in FIG. 5 (b), the battery exterior body made of one member is formed by heat-sealing the first base material layer around the recess 51 and the first base material layer in the second region 552. The secondary battery 60 to have is obtained. That is, in the battery shown in FIG. 5B, the upper surface of the recess 51 is covered with the second region 552, so that the recess 51 and the second region 552 form an internal space for accommodating the battery.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these examples.

[Examples 1 to 14, Comparative Examples 1 to 7]
(Example 1)
First, a stainless steel foil having a thickness of 20 μm was prepared. A water-soluble paint (coating amount 12 g / m ² ) is applied to both sides of the stainless steel foil, and the mixture is heated and dried in an oven at 200 ° C. to obtain a first corrosion prevention layer and a second corrosion prevention layer having a thickness of about 0.2 μm. Each layer was formed.
Water-soluble coating, a 0.2 wt% poly (vinyl alcohol) backbone containing amorphous polymer having a hydroxyl group, and 0.8% by weight of FeCl ₂ · 4H ₂ O, nitrilotris (methylene phosphonic acid) (trade name: Chelest PH -320, manufactured by Kirest Co., Ltd.) is an aqueous solution prepared by dissolving 0.7% by mass in water.

Then, the first adhesive was applied onto the formed first corrosion prevention layer to form a first adhesive layer having a thickness of 3 μm.
The first adhesive is a phenol novolac type epoxy resin having a bisphenol A structure and 15% by mass of maleic anhydride-modified polypropylene (melting point 50 ° C.) (manufactured by Mitsubishi Chemical Corporation, trade name: jER157S70, viscosity = 80, It was obtained by melt-kneading 7% by mass of epoxy equivalent = 210) with toluene for 10 minutes at room temperature so that the solid content was 15%.

The first adhesive layer at the time of manufacturing the laminate containing the stainless steel foil and the first base material layer made of a polypropylene resin film having a thickness of 6 μm were laminated by dry laminating at the laminating temperature shown in Table 1. The surface of the stainless copper foil after dry lamination was visually observed and evaluated under the following evaluation conditions. The results are shown in Table 1 as "folded wrinkles".
◯: No wrinkles or breaks occurred on the stainless steel foil.
X: Wrinkles and / or breaks occurred in the stainless steel foil.

Further, on a second base material layer made of a stretched polyethylene terephthalate (PET) resin film having a black color and having a thickness of 6 to 8 μm, a urethane adhesive (main agent: TM-K55 (trade name, manufactured by Toyo Morton Co., Ltd.), A second adhesive layer (thickness 3 μm) made of a curing agent: CAT-10L (trade name, manufactured by Toyo Morton Co., Ltd.) was formed by coating.
The second adhesive layer and the second corrosion prevention layer in the above-mentioned laminate were opposed to each other and laminated by dry lamination at 80 ° C. to obtain a battery exterior laminate.

A test piece was collected from this battery exterior laminate, and the test piece was used as an electrolytic solution containing 1000 ppm of purified water (ethylene carbonate (DC) / diethyl carbonate (DEC) 1: 1 vol% to which 1 mol / liter of LiPF ₆ was added. It was immersed in an electrolytic solution) and kept at a temperature of 80 ° C. for 3 days.
After immersion in the electrolytic solution for 3 days, a tensile test was performed without wiping off the electrolytic solution. The tensile test conforms to the peeling measurement method A (peeling in the 90 ° direction) specified in JIS C6471 "Copper-clad laminate test method for flexible printed wiring boards", and is a tensile tester (Nippon Densan Symposium Co., Ltd.) ), Product name: FGS-50E-H. The results of evaluation based on the following evaluation criteria are shown in Table 1 as "electrolyte resistance".
A: 4N / 15mm or more B: Less than 4N / 15mm, 0.1N / 15mm or more C: Measurement is not possible because it has completely peeled off.

Further, after immersion in the electrolytic solution for 3 days, immersion in water for 1 hour, visual observation was performed, and evaluation was performed according to the following evaluation criteria. The results are shown in Table 1 as "after immersion in water".
A: No delamination (peeling between layers) is observed B: Some delamination is observed but within the permissible range C: Completely peeled off

(Example 2)
The same as in Example 1 except that maleic anhydride-modified polypropylene (melting point 60 ° C.) was used in place of maleic anhydride-modified polypropylene (melting point 50 ° C.) in the first adhesive forming the first adhesive layer. Then, a laminate for the battery exterior was manufactured, and the same evaluation as in Example 1 was performed.
The results are shown in Table 1.

(Example 3)
The same as in Example 1 except that maleic anhydride-modified polypropylene (melting point 80 ° C.) was used instead of maleic anhydride-modified polypropylene (melting point 50 ° C.) in the first adhesive forming the first adhesive layer. Then, a laminate for the battery exterior was manufactured, and the same evaluation as in Example 1 was performed.
The results are shown in Table 1.

(Example 4)
The same as in Example 1 except that maleic anhydride-modified polypropylene (melting point 100 ° C.) was used instead of maleic anhydride-modified polypropylene (melting point 50 ° C.) in the first adhesive forming the first adhesive layer. Then, a laminate for the battery exterior was manufactured, and the same evaluation as in Example 1 was performed. The results are shown in Table 1.

(Example 5)
In the first adhesive forming the first adhesive layer, the same as in Example 3 except that an adhesive having only maleic anhydride-modified polypropylene (melting point 80 ° C.) and no phenol novolac type epoxy resin was used. In the same manner, a laminate for battery exterior was manufactured and evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 6)
As a water-soluble paint forming the first and second corrosion prevention layers, only 0.7% by mass of nitrilotris (methylenephosphonic acid) (trade name: Kirest PH-320, manufactured by Kirest Co., Ltd.) is dissolved in water. A laminate for battery exterior was produced in the same manner as in Example 3 except that the aqueous solution was used, and the same evaluation as in Example 1 was performed. The results are shown in Table 1.

(Example 7)
As the water-soluble coating material forming the first and second corrosion prevention layers, the same as in Example 3 except that an aqueous solution obtained by dissolving only 0.2% by mass of the polyvinyl alcohol skeleton-containing non-crystalline polymer having a hydroxyl group in water was used. In the same manner, a laminate for battery exterior was manufactured and evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 8)
As the water-soluble paint forming the first and second anti-corrosion layer, except that only 0.8 mass% of CrF 3 · _3H 2 _O was used an aqueous solution obtained by dissolving in water in the same manner as in Example 3, A laminate for the battery exterior was manufactured and evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 9)
As the water-soluble paint forming the first and second anti-corrosion layer, except that only 0.8% by weight of FeCl 3 · _6H 2 _O was used an aqueous solution obtained by dissolving in water in the same manner as in Example 3, A laminate for the battery exterior was manufactured and evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Examples 10 to 12)
Lamination for battery exterior in the same manner as in Example 3 except that the dry lamination temperature of the first adhesive layer and the first base material layer in the laminate containing the stainless steel foil was changed to the temperature shown in Table 1. A body was produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 13)
As the water-soluble paint forming the first and second anti-corrosion layer, a 0.2 wt% poly (vinyl alcohol) backbone containing amorphous polymer having a hydroxyl group, and 0.8 wt% of _CrF 3 · 3H ₂ O, nitrilotris For battery exterior in the same manner as in Example 3 except that an aqueous solution prepared by dissolving 0.7% by mass of (methylenephosphonic acid) (trade name: Kirest PH-320, manufactured by Kirest Co., Ltd.) in water was used. A laminate was produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 14)
As the water-soluble paint forming the first and second anti-corrosion layer, a 0.2 wt% poly (vinyl alcohol) backbone containing amorphous polymer having a hydroxyl group, and 0.8 wt% of ZrF _4, nitrilotris (methylene phosphonic acid ) (Product name: Kirest PH-320, manufactured by Kirest Co., Ltd.) Manufactures a laminate for battery exterior in the same manner as in Example 3 except that an aqueous solution prepared by dissolving 0.7% by mass in water was used. Then, the same evaluation as in Example 1 was performed. The results are shown in Table 1.

(Comparative Example 1)
The same as in Example 1 except that maleic anhydride-modified polypropylene (melting point 140 ° C.) was used instead of maleic anhydride-modified polypropylene (melting point 50 ° C.) in the first adhesive forming the first adhesive layer. Then, a laminate for the battery exterior was manufactured, and the same evaluation as in Example 1 was performed. The results are shown in Table 1.

(Comparative Example 2)
A battery exterior laminate was produced in the same manner as in Example 3 except that an aluminum foil having a thickness of 40 μm was used as the metal foil instead of the stainless steel foil, and the same evaluation as in Example 1 was performed.
The results are shown in Table 1.

(Comparative Example 3)
A battery exterior laminate was produced in the same manner as in Example 3 except that an aluminum foil having a thickness of 20 μm was used as the metal foil instead of the stainless steel foil, and the same evaluation as in Example 1 was performed.
The results are shown in Table 1.

(Comparative Example 4)
The battery exterior is the same as in Example 3 except that the dry laminate between the first adhesive layer and the first base material layer in the laminate containing the stainless steel foil is changed to the thermal laminate at the temperature shown in Table 1. A laminate for use was produced, and the same evaluation as in Example 1 was performed. The results are shown in Table 1.

(Comparative Example 5)
The battery exterior is the same as in Comparative Example 1 except that the dry laminate between the first adhesive layer and the first base material layer in the laminate containing the stainless steel foil is changed to the thermal laminate at the temperature shown in Table 1. A laminate for use was produced, and the same evaluation as in Example 1 was performed. The results are shown in Table 1.

(Comparative Example 6)
The dry laminate between the first adhesive layer and the first base material layer in the laminate containing the stainless steel foil was changed to the thermal laminate at the temperature shown in Table 1, and the metal foil was replaced with the stainless steel foil. A laminated body for battery exterior was produced in the same manner as in Comparative Example 1 except that an aluminum foil having a thickness of 40 μm was used, and the same evaluation as in Example 1 was performed. The results are shown in Table 1.

(Comparative Example 7)
A battery exterior laminate was produced in the same manner as in Example 3 except that the first corrosion prevention layer and the second corrosion prevention layer were not provided, and the same evaluation as in Example 1 was performed. The results are shown in Table 1.

In Table 1, each abbreviation has the following meaning.
(Ad-PP1): Maleic anhydride-modified polypropylene (melting point 50 ° C.)
(Ad-PP2): Maleic anhydride-modified polypropylene (melting point 60 ° C.)
(Ad-PP3): Maleic anhydride-modified polypropylene (melting point 80 ° C.)
(Ad-PP4): Maleic anhydride-modified polypropylene (melting point 100 ° C.)
(Ad-PP5): Maleic anhydride-modified polypropylene (melting point 140 ° C.)
(Ad-EP1): "jER157S70" (trade name, manufactured by Mitsubishi Chemical Corporation) (phenol novolac type epoxy resin having a bisphenol A structure; viscosity = 80; epoxy equivalent = 210)
(M1): 0.2 wt% polyvinyl alcohol skeleton-containing non-crystalline polymer having a hydroxyl group, 0.8% by weight of FeCl ₂ · 4H ₂ O, and nitrilotris (methylene phosphonic acid) (trade name: CHELEST PH-320 , 0.7% by mass aqueous solution of Kirest Co., Ltd. (M2): 0.7% by mass aqueous solution of nitrilotris (methylenephosphonic acid) (trade name: Kirest PH-320, manufactured by Kirest Co., Ltd.) M3): 0.2 wt% aqueous solution (M4 polyvinyl alcohol skeleton-containing non-crystalline polymer having a hydroxyl group): _CrF 3 · 3H ₂ O 0.8% by weight aqueous solution _{(M5): FeCl 3 · 6H} 2 0 in O. 8% by weight aqueous solution (M6): 0.2 wt% polyvinyl alcohol skeleton-containing non-crystalline polymer having a hydroxyl group, _CrF 3 · 3H ₂ O 0.8 wt% of nitrilotris (methylene phosphonic acid) (trade name: Chelest PH-320, an aqueous solution having 0.7 wt% of Chelest Corp.) (M7): 0.2 wt% polyvinyl alcohol skeleton-containing non-crystalline polymer having a hydroxyl group, 0.8 wt% of ZrF _4, nitrilotriacetic Aqueous solution (SUS1) containing 0.7% by mass of su (methylenephosphonic acid) (trade name: Kirest PH-320, manufactured by Kirest Co., Ltd.): Stainless steel foil (AL1) with a thickness of 20 μm: Aluminum with a thickness of 40 μm Foil (AL2): Aluminum foil with a thickness of 20 μm

As is clear from the results shown in Table 1, the battery exterior laminates of Examples 1 to 14 do not wrinkle or break the stainless steel foil, and peeling is reduced even when they come into contact with an electrolytic solution or water. It had good mechanical strength, and had excellent characteristics (workability, mechanical strength, chemical / water resistance) as compared with the battery exterior laminates of Comparative Examples 1 to 7.

Claims (8)

A battery exterior laminate comprising at least a first base material layer, a first adhesive layer, a first corrosion prevention layer, a stainless steel foil, and a second base material layer in this order.
The first base material layer is a layer containing polypropylene or polyethylene.
The first adhesive layer comprises an adhesive containing a polyolefin having a melting point of 50 to 100 ° C.
A laminated body for battery exterior, characterized in that the thickness of the stainless steel foil is 40 μm or less. The battery exterior laminate according to claim 1, wherein the first corrosion prevention layer is a layer containing a water-soluble resin. The second base material layer is a layer made of polyethylene terephthalate and having a thickness of 3 to 11 μm.
The battery exterior laminate according to claim 1 or 2, which has a second adhesive layer between the second base material layer and the stainless steel foil. The first adhesive layer is a layer composed of an adhesive containing an acid-modified polyolefin resin having a melting point of 50 to 100 ° C. and a phenol novolac type epoxy resin, according to any one of claims 1 to 3. The described battery exterior laminate. The battery exterior laminate according to any one of claims 2 to 4, wherein the first corrosion prevention layer contains a water-soluble resin, a metal halide compound, and a chelating agent. A method for manufacturing a battery exterior laminate according to any one of claims 1 to 5, wherein the battery exterior laminate is manufactured.
Having a step of arranging the first adhesive layer formed on one side of the stainless steel foil so as to be in contact with the first base material layer and dry-laminating the laminate at 70 to 150 ° C. A characteristic method for manufacturing a battery exterior laminate. A battery exterior body comprising the battery exterior laminate according to any one of claims 1 to 5.
A battery exterior body having an internal space for accommodating a battery, wherein the side of the first base material layer of the battery exterior laminate is the side of the internal space. A battery comprising the battery exterior according to claim 7.

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