CN113263812B

CN113263812B - Laminate for battery outer package, and battery

Info

Publication number: CN113263812B
Application number: CN202110534292.7A
Authority: CN
Inventors: 饭塚宏和; 佐藤友纪; 武井邦浩; 金田康宏; 宫胁晃
Original assignee: Fujimori Kogyo Co Ltd
Current assignee: Fujimori Kogyo Co Ltd
Priority date: 2015-09-17
Filing date: 2016-08-03
Publication date: 2022-11-29
Anticipated expiration: 2036-08-03
Also published as: CN110281612B; CN113263812A; CN110281612A; CN106541641A

Abstract

The invention provides a novel laminate for battery outer packaging, which can realize a thin film, has excellent characteristics, and can be manufactured with high yield and high productivity. The laminate for battery exterior packaging is a laminate for battery exterior packaging comprising at least a first base material layer, a first adhesive layer, a first anticorrosive layer, a stainless steel foil, and a second base material layer in this order, and is characterized in that the first base material layer is a layer composed of a polyolefin, and the first adhesive layer is a layer composed of an adhesive containing 100 parts by mass of an acid-modified polyolefin resin (A) and 1 to 20 parts by mass of a compound (B) having a plurality of epoxy groups.

Description

Laminate for battery outer package, and battery

This application is a divisional application of the chinese patent application having a filing date of 2016, 8/3/2016, and a chinese patent application number of 201610629152.7 entitled "laminate for battery sheathing, battery sheathing body, and battery", and is claimed to have priority to japanese applications having filing numbers of 2015-184343 and 2016-116658.

Technical Field

The present invention relates to a laminate for battery exterior packaging that is excellent as an exterior package for secondary batteries, capacitors, and the like, and a battery exterior package and a battery obtained using the laminate.

Background

With the increase of environmental awareness and the effective use of natural energy such as sunlight and wind power, attention is being paid to secondary batteries such as lithium ion batteries and capacitors such as electric double layer capacitors for storing electric energy.

For the purpose of downsizing and weight reduction, a laminate for battery outer packaging in which a metal foil and a resin layer are laminated can be used as an outer packaging body used for these batteries. Such a battery exterior laminate is formed into a disk shape having a concave portion by drawing molding or the like, and is used as an exterior container body.

The battery exterior laminate is molded to obtain an exterior lid portion in the same manner as the exterior container body. After the battery body is housed in the recess of the outer container body, the outer container lid is overlapped so as to cover the housed battery body, and the edge portion between the container body and the outer container lid is bonded to obtain a battery in which the battery body is housed in the outer container.

For example, patent document 1 discloses a laminate for battery outer packaging in which a base material layer, an aluminum foil, and an innermost layer composed of a polypropylene or polyethylene layer are laminated in this order.

Documents of the prior art

Patent document

Patent document 1: japanese unexamined patent publication No. 2012-33393

Disclosure of Invention

Technical problem to be solved by the invention

As the application field of batteries such as secondary batteries expands, development of small-sized batteries having a large capacity has been advanced. Similarly, the laminate for battery outer packaging is also required to be thin 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 properties of the laminate for battery outer packaging are mainly ensured by the inorganic layer such as a metal foil in the laminate for battery outer packaging. As a metal foil, an aluminum foil excellent in workability is widely used (see patent document 1).

However, aluminum foil is superior in workability to other metal foils, and therefore can be used to produce a laminate with a high yield, while mechanical strength such as puncture strength is inferior to other metal foils. Therefore, the thickness of the aluminum foil cannot be made constant or less in order to obtain mechanical strength, and it is difficult to make the laminate for battery outer packaging thin in the current situation where the aluminum foil is used.

The present invention has been made in view of the above-described current situation, and an object thereof is to provide a laminate for battery exterior packaging which can be made thin and has excellent various properties.

Means for solving the problems

The inventors of the present invention have made repeated investigations to achieve the above object, and as a result, have adopted the following configuration: by using a stainless steel foil instead of an aluminum foil, a film can be formed while mechanical strength such as puncture strength is ensured. However, it has been found that when a laminate for battery exterior packaging is produced using a stainless steel foil, there are technical problems in terms of surface defects and electrolyte resistance, which are considered to be caused by adhesion failure that has not been found in conventional aluminum foils. The inventors of the present invention have made intensive studies and succeeded in newly finding an adhesive agent which can suitably bond a stainless steel foil surface-treated with an anticorrosive agent and a base material layer, and have completed the present invention.

Namely, the present invention adopts the following constitution:

a first aspect of the present invention is a laminate for battery exterior packaging comprising at least a first base material layer, a first adhesive layer, a first corrosion-resistant layer, a stainless steel foil, and a second base material layer in this order, wherein the first base material layer is a layer made of polyolefin, and the first adhesive layer is a layer made of an adhesive containing 100 parts by mass of an acid-modified polyolefin resin (a) and 1 to 20 parts by mass of a compound (B) having a plurality of epoxy groups.

The compound having a plurality of epoxy groups is preferably a phenol novolak type epoxy resin (phenonol novolak type epoxy resin).

The epoxy equivalent of the novolac epoxy resin is preferably 100 to 300.

The novolac epoxy resin preferably has a bisphenol a structure.

The first corrosion protection layer preferably contains a halogenated metal compound.

The halogenated metal compound is preferably a chloride or fluoride of iron, chromium, manganese or zirconium.

The first corrosion prevention layer preferably contains a resin having a polyvinyl alcohol skeleton, a fluorinated metal compound, and a phosphoric acid compound.

The thickness of the stainless steel foil is preferably 10 to 30 μm.

The first substrate layer is preferably homo polypropylene or block polypropylene.

A second aspect of the present invention is a battery exterior body including the battery exterior laminate according to the first aspect, wherein the battery exterior body has an internal space for housing a battery, and the first base material layer side of the battery exterior laminate is the internal space side.

A third aspect of the present invention is a battery having the battery exterior casing according to the second aspect.

Effects of the invention

According to the present invention, a laminate for battery exterior packaging which has excellent characteristics and can be produced with high yield and high productivity can be provided. The laminate for battery exterior packaging of the present invention can be made thin.

Drawings

Fig. 1 is a schematic cross-sectional view showing a first embodiment of a battery exterior laminate of the present invention.

Fig. 2 is a perspective view showing an example of a secondary battery manufactured using the battery exterior laminate of the present invention.

Fig. 3 is a perspective view showing a process for manufacturing a secondary battery using the battery exterior laminate of the present invention.

Fig. 4 is a perspective view showing a process for manufacturing a secondary battery using the battery exterior laminate of the present invention.

Detailed Description

The present invention will be described below with reference to preferred embodiments. However, the present embodiment is a more specific description of the gist of the invention, and the invention is not limited to the specific embodiments.

[ laminate for external packaging of Battery ]

The laminate for battery exterior packaging according to the first aspect of the present invention (hereinafter, may be simply referred to as "laminate") is a laminate for battery exterior packaging comprising at least a first base material layer, a first adhesive layer, a first anticorrosive layer, a stainless steel foil, and a second base material layer in this order, wherein the first base material layer is a layer composed of a polyolefin, and the first adhesive layer is a layer composed of an adhesive containing 100 parts by mass of an acid-modified polyolefin resin (a) and 1 to 20 parts by mass of a compound (B) having a plurality of epoxy groups.

Fig. 1 is a cross-sectional view showing a schematic structure of a battery exterior laminate 10 according to an embodiment of the present invention.

The laminate 10 of the present embodiment includes a first base material layer 11, a first adhesive layer 12, a first anticorrosive layer 13, a stainless steel foil 14, a second anticorrosive layer 16, a second adhesive layer 17, and a second base material layer 15 in this order.

That is, the laminate 10 of the present embodiment is configured by a 7-layer structure including a first corrosion prevention layer 13 and a second corrosion prevention layer 16 formed on both surfaces of a stainless steel foil 14, a first base material layer 11 laminated on the first corrosion prevention layer 13 via a first adhesive layer 12, and a second base material layer 15 laminated on the second corrosion prevention layer 16 via a second adhesive layer 17.

Each layer is described in detail below.

The first base material layer 11 is a layer made of polyolefin. Examples of the layer composed of polyolefin include polyethylene, polypropylene, poly-1-butene, polyisobutylene, polyethylene, a random copolymer of propylene and ethylene or α -olefin, and a block copolymer of propylene and ethylene or α -olefin.

Among them, polypropylene resins such as homopolypropylene (propylene homopolymer; hereinafter, sometimes referred to as "homopolypp"), a propylene-ethylene block copolymer (hereinafter, sometimes referred to as "block PP"), and a propylene-ethylene random copolymer (hereinafter, sometimes referred to as "random PP") are preferable from the viewpoint of improving adhesiveness to the first adhesive layer 12. Among them, homopolypropylene or block PP is more preferable, and block PP is particularly preferable because of its excellent mechanical strength.

The first substrate layer 11 may have a single-layer structure or a multilayer structure.

The melting point of the layer composed of polyolefin used for the first base material layer 11 is not particularly limited as long as the laminate 10 for battery exterior packaging has the required heat resistance.

For example, the thickness of the first base material layer 11 may be 1 to 30 μm.

The first adhesive layer 12 is a layer composed of an adhesive containing 100 parts by mass of an acid-modified polyolefin resin (a) and 1 to 20 parts by mass of a compound (B) having a plurality of epoxy groups.

The laminate for battery outer packaging requires various properties such as mechanical strength, water resistance, and chemical resistance (electrolyte resistance). These properties are mostly borne by the metal foil in the laminate for battery outer packaging, and the metal foil of the battery outer packaging plays a very important role in terms of battery durability. In addition, when the battery is used, a metal foil subjected to rust prevention treatment is often used in order to prevent the metal foil from being deteriorated by rust or the like.

The structure of an anticorrosion treatment agent (anticorrosion layer) having a good anticorrosion effect is widely known for aluminum foils used in the past.

On the other hand, in the present invention, a stainless steel foil is used in order to achieve both thinning and mechanical strength (puncture strength and the like). As is well known, stainless steel is less likely to rust in metals, but stainless steel foils of battery exterior laminates used in extreme situations such as contact with electrolyte solutions are preferably subjected to rust prevention treatment in the same manner as in the prior art. Therefore, the rust-preventive agent capable of imparting a good rust-preventive effect to the stainless steel foil may have a different composition from that of the conventional rust-preventive agent for aluminum foil.

However, as a result of providing the first anticorrosive layer composed of the anticorrosive agent for stainless steel foil on the surface of the stainless steel foil, the conventional adhesive was not able to satisfactorily adhere the surface of the first anticorrosive layer and the surface of the first base material layer, and a surface defect was found to occur due to adhesion failure.

The inventors of the present invention have further studied and found an adhesive comprising 100 parts by mass of an acid-modified polyolefin resin (a) and 1 to 20 parts by mass of a compound (B) having a plurality of epoxy groups as an adhesive capable of satisfactorily bonding a rust-preventive layer (first corrosion-preventive layer) for a stainless steel foil to a first base material layer.

Then, by using the first base material layer, the first adhesive layer composed of such an adhesive, the first anticorrosive layer, and the stainless steel foil, the following effects can be achieved: (1) The mechanical strength (puncture strength and the like) is improved and the thinning is realized through the stainless steel foil; (2) The rust prevention effect of the stainless steel foil is improved by the first corrosion prevention layer, and thus the durability is improved; (3) The first adhesive layer improves the mechanical strength (peel strength, etc.), reduces the occurrence of surface defects caused by poor adhesion during the production of the laminate, and improves the yield.

Adhesive agent

The adhesive forming the first adhesive layer 12 in the present invention contains 100 parts by mass of the acid-modified polyolefin resin (a) and 1 to 20 parts by mass of the compound (B) having a plurality of epoxy groups.

Hereinafter, the acid-modified polyolefin resin (a) may be referred to as the "component (a)" and the compound (B) having a plurality of epoxy groups may be referred to as the "component (B)".

(acid-modified polyolefin resin (A))

In the present invention, the acid-modified polyolefin resin (a) is a polyolefin resin modified with an unsaturated carboxylic acid or a derivative thereof, and the polyolefin resin has an acid functional group such as a carboxyl group or a carboxylic acid anhydride group.

(A) The component (B) is obtained by modifying a polyolefin resin with an unsaturated carboxylic acid or a derivative thereof, or by copolymerizing an acid functional group-containing monomer with an olefin. Among these, the polyolefin resin is preferably acid-modified as the component (A).

Examples of the acid modification method include graft modification of a polyolefin resin and an acid functional group-containing monomer by melt kneading (melt-kneading) 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 an α -olefin, and a block copolymer of propylene and ethylene or an α -olefin. Among these, polypropylene resins such as homopolypropylene (propylene homopolymer; hereinafter, sometimes referred to as "homopolyPP"), a propylene-ethylene block copolymer (hereinafter, sometimes referred to as "block PP"), and a propylene-ethylene random copolymer (hereinafter, sometimes referred to as "random PP") are preferable, and random PP is particularly preferable.

Examples of the olefins in the case of copolymerization include olefin 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, a carboxyl group or a carboxylic anhydride group in the same molecule, and examples thereof include various unsaturated monocarboxylic acids, dicarboxylic acids or anhydrides of dicarboxylic acids.

Examples of the acid functional group-containing monomer having a carboxyl group (carboxyl group-containing monomer) include α, β -unsaturated carboxylic acid monomers such as acrylic acid, methacrylic acid, maleic acid, nadic acid, fumaric acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, tetrahydrophthalic acid, and endo [2.2.1] -5-heptene-2,3-dicarboxylic acid (5-norbornene-2,3-dicarboxylic acid (endic acid)).

Examples of the acid functional group-containing monomer having a carboxylic anhydride group (carboxylic anhydride group-containing monomer) include unsaturated dicarboxylic anhydride monomers such as maleic anhydride, nadic anhydride, itaconic anhydride, citraconic anhydride, and nadic anhydride.

These acid functional group-containing monomers may be used alone or in combination of two or more in the component (A).

Among these, the acid-functional group-containing monomer is preferably an acid-functional group-containing monomer having an acid anhydride group, more preferably a carboxylic acid anhydride group-containing monomer, and particularly preferably maleic anhydride, because of high reactivity with the component (B) described later.

When a part of the acid functional group-containing monomer used for acid modification is unreacted, it is preferable to use a monomer obtained by previously removing the unreacted acid functional group-containing monomer as the component (a) in order to prevent a decrease in adhesive strength due to the unreacted acid functional group-containing monomer.

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

(A) The melting point of the component (b) is not particularly limited.

For example, the adhesive used in the present invention does not contain an organic solvent, and when the component (a) and the component (B) described later are melt-kneaded to form the adhesive, the melting point of the component (a) is preferably 100 to 180 ℃. An adhesive layer composed of such an adhesive can be suitably used as the adhesive layer for thermal lamination.

By using the (A) component having a melting point within the above range, even in the case of using a conventional method and a general apparatus, the (A) component and the (B) component described later can be melt-kneaded at a temperature sufficiently higher than the melting point of the (A) component. When the component (a) is reacted with the component (B) described later by melt kneading, the melting point of the component (B) is preferably lower than that of the component (a), and the degree of freedom in selecting the component (B) can be increased by using the component (a) having the melting point in the above range.

As described above, the melting point of component (a) is preferably higher than the melting point of component (B) described later, more preferably the melting point of component (a) is higher than the melting point of component (B) by 10 ℃ or more, still more preferably 20 ℃ or more, and particularly preferably 30 ℃ or more. Since the melting point of the component (A) is sufficiently higher than that of the component (B), the component (B) melts first and penetrates into the component (A) in a state of retaining the resin shape when melt-kneading is performed, and the component (A) and the component (B) react uniformly, whereby good durability can be obtained.

On the other hand, when the first adhesive layer 12 is a dry lamination adhesive layer, the melting point of the component (a) is preferably 50 to 100 ℃. By providing a layer composed of an adhesive containing a polyolefin having a relatively low melting point with a melting point of 50 to 100 ℃, the stainless steel foil having the first corrosion-resistant layer and the first base material layer can be bonded to each other via the first adhesive layer at a relatively low temperature at which deformation does not occur in the stainless steel foil, that is, at a temperature near 100 ℃ or lower.

Among these, maleic anhydride-modified polypropylene is preferable as the component (a) from the viewpoint of adhesiveness and an appropriate melting point.

(Compound (B) having plural epoxy resins)

(B) The component is a compound with a plurality of epoxy groups. (B) The component (C) may be a low molecular compound or a high molecular compound. The component (B) is preferably a polymer compound (resin) from the viewpoint of good mixing with the component (A). On the other hand, the component (B) is preferably a low molecular weight compound in view of good solubility in a solvent.

(B) The structure of the component (a) is not particularly limited as long as it has a plurality of epoxy groups, and examples thereof include phenoxy resins synthesized from bisphenols and epichlorohydrin, novolac epoxy resins, and bisphenol epoxy resins. Among them, a novolak type epoxy resin is preferably used because of its high epoxy content per molecule and, in particular, it is possible to form a dense crosslinked structure with the (A) component.

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

Among them, as the novolac epoxy resin, a bisphenol a novolac epoxy resin having a novolac structure as a basic skeleton and simultaneously having a bisphenol a structure is preferable. In addition, the bisphenol a structure in the epoxy novolac resin may be a structure derived from bisphenol a, or hydroxyl groups at both ends of bisphenol a may be replaced with groups containing an epoxy group or the like.

As an example of the bisphenol a novolac epoxy resin, a resin represented by the following general formula (1) can be cited.

[ chemical formula 1]

In the formula (1), R ¹ ～R ⁶ Each independently hydrogen atom or methyl, n is an integer of 0 to 10, R ^X Is a group having an epoxy group.

In the formula (1), R ¹ ～R ⁶ Are each independently a hydrogen atom or a methyl group. When n is an integer of 2 or more, R ³ 、R ⁴ Each may be the same or different.

In the resin represented by the formula (1), at least one of the following (i) to (iii) is preferably satisfied.

(i)R ¹ And R ² Both are methyl;

(ii)R ³ and R ⁴ Both are methyl;

(iii)R ⁵ and R ⁶ Both are methyl groups.

For example, by satisfying the above (i), in the formula (1), R ¹ And R ² The bonded carbon atom and the two hydroxyphenyl groups bonded to the carbon atom constitute a structure derived from bisphenol A.

In the formula (1), R ^X 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 among them, a glycidyl group is preferable.

The epoxy equivalent of the bisphenol A novolac epoxy resin is preferably 100 to 300, more preferably 200 to 300. The molecular weight of an epoxy resin having an epoxy equivalent (g/eq) of 1 epoxy group, and a smaller value means a larger number of epoxy groups in the resin. By using an epoxy resin having a small epoxy equivalent, the adhesion of the novolac epoxy resin to the adherend is good and the novolac epoxy resin and the acid-modified polyolefin resin are sufficiently crosslinked even in the case where the added amount of the novolac epoxy resin is small.

As such bisphenol A novolac epoxy resins, jER154, jER157S70, jER-157S65; commercially available products such as EPICLON N-730A, EPICLON N-740, EPICLON-770 and EPICLON-775 (trade names) available from DIC.

It is considered that, by using the above-mentioned epoxy resin, both the acid functional group of the component (a) and the epoxy group of the component (B) function as adhesive functional groups to an adherend (particularly, functional groups such as hydroxyl groups of the adherend), excellent adhesion to the first base material layer 11 and the first corrosion-resistant layer 13 can be achieved.

Further, it is considered that a part of the acid functional group of the component (a) and a part of the epoxy group of the component (B) react with each other to form a crosslinked structure of the component (a) and the component (B), and the crosslinked structure enhances the strength of the resin, thereby obtaining excellent adhesiveness and also good durability.

The adhesive used in the present invention preferably contains the component (B) in an amount of 1 to 20 parts by mass based on 100 parts by mass of the component (a), more preferably 5 to 10 parts by mass based on 100 parts by mass of the component (a), and most preferably 5 to 7 parts by mass based on 100 parts by mass of the component (a).

The adhesive used in the present invention may contain additives having miscibility, additional resins, plasticizers, stabilizers, colorants, and the like as needed.

The adhesive of the present invention may or may not further contain an organic solvent.

The adhesive that is in a liquid state by containing an organic solvent can be an adhesive suitable for dry lamination, for example. The adhesive layer can be formed by applying and drying such a liquid adhesive to the layer as the lower layer.

On the other hand, in the case where 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, followed by extrusion molding or the like.

When the organic solvent is contained, the organic solvent used is not particularly limited as long as it can suitably dissolve the 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, and still more preferably 10 to 20% by mass.

The thickness of the first adhesive layer 12 may be, for example, 0.5 to 10 μm. When the thickness is within this range, the first base material layer 11 and the stainless steel foil 14 can be bonded with high adhesion, and delamination can be prevented.

In this embodiment, the first corrosion prevention layer 13 is a layer for preventing corrosion of the stainless steel foil 14 due to rust or the like.

The first corrosion prevention layer 13 preferably contains a halogenated metal compound, and the halogenated metal compound described later may be directly plated on the surface of the stainless steel foil 14. By providing such a first corrosion prevention layer 13, a good rust prevention effect can be imparted to the stainless steel foil.

Among them, the first corrosion prevention layer 13 preferably further contains a water-soluble resin, and is preferably formed by applying a water-soluble paint containing a water-soluble resin, a halogenated metal compound, and a chelating agent, and then drying and curing the paint.

Water-soluble paint

(Water-soluble resin)

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

The polyvinyl alcohol resin is a water-soluble resin of at least one kind selected from a polyvinyl alcohol resin and a modified polyvinyl alcohol resin.

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

Examples of the polymer or copolymer of the vinyl ester monomer include homopolymers or copolymers of vinyl ester monomers such as fatty acid vinyl esters such as vinyl formate, vinyl acetate and vinyl butyrate and aromatic vinyl esters such as vinyl benzoate, and copolymers of these monomers with other monomers copolymerizable therewith.

Examples of the other copolymerizable monomers include olefins such as ethylene and propylene, ether group-containing monomers such as alkyl vinyl ethers, carbonyl group-containing (keto group) -containing monomers such as diacetone acrylamide, diacetone (meth) acrylate, allyl acetoacetate and acetoacetic ester, unsaturated carboxylic acids such as acrylic acid, methacrylic acid and maleic anhydride, halogenated ethylenes such as vinyl chloride and vinylidene chloride, and unsaturated sulfonic acids.

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

Examples of the polyvinyl alcohol resin include alkyl ether-modified polyvinyl alcohol resins, carbonyl-modified polyvinyl alcohol resins, acetoacetyl-modified polyvinyl alcohol resins, acetamide-modified polyvinyl alcohol resins, acrylonitrile-modified polyvinyl alcohol resins, carboxyl-modified polyvinyl alcohol resins, silicone-modified polyvinyl alcohol resins, and ethylene-modified polyvinyl alcohol resins. Among them, alkyl ether-modified polyvinyl alcohol resins, carbonyl-modified polyvinyl alcohol resins, carboxyl-modified polyvinyl alcohol resins, and acetoacetyl-modified polyvinyl alcohol resins are preferable.

As a general commercially available product of the polyvinyl alcohol-based resin, for example, J-POVAL DF-20 (trade name) manufactured by VAM & POVAL, japan, and CROSSMER H series (trade name) manufactured by CARBIDE, japan can be mentioned. The polyvinyl alcohol resin may be a mixture of 1 or 2 or more species.

Examples of the polyvinyl ether resin include homopolymers or copolymers of aliphatic vinyl ethers such as 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, norbornene vinyl ether, 2-hydroxyethyl vinyl ether, and diethylene glycol vinyl ether, and copolymers of other monomers copolymerizable therewith. Examples of the other monomer copolymerizable with the vinyl ether monomer include the same monomers as those copolymerizable with the vinyl ester monomer.

In particular, polyvinyl ether resins containing an aliphatic vinyl ether having a hydroxyl group in the monomer, such as 2-hydroxyethyl vinyl ether, diethylene glycol monoethyl ether, 2-hydroxypropyl vinyl ether, and monovinyl ethers of various other dihydric or polyhydric alcohols, are water-soluble and can undergo a crosslinking reaction with respect to the hydroxyl group, and therefore can be suitably used in the present invention.

These polyvinyl ether resins can be produced without saponification treatment, unlike polyvinyl alcohol resins produced via vinyl ester polymers, since vinyl ether monomers can be used in the production (polymerization) step of the resins. Further, a copolymer containing a vinyl ester monomer or a vinyl ether monomer, or a vinyl alcohol-vinyl ether copolymer obtained by saponifying the same may be used. A mixture of a polyvinyl alcohol resin and a polyvinyl ether resin other than the polyvinyl ether resin may be used.

As the water-soluble resin, either one of a polyvinyl alcohol resin and a polyvinyl ether resin may be used alone, or two of them may be used in combination.

(halogenated Metal Compound)

The metal halide compound is preferably water-soluble because it needs to be mixed with the water-soluble resin.

Examples of the metal halide compound include a chromium halide, an iron halide, a zirconium halide, a titanium halide, a hafnium halide, a titanium hydrohalide (チタンハロゲン hydrohalic acid), 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 halogenated metal compound, a chloride or fluoride of iron, chromium, manganese or zirconium is preferable.

The halogenated metal compound has an effect of improving chemical resistance such as electrolyte resistance. I.e., passivating the surface of the stainless steel foil 14, may improve corrosion resistance to the electrolyte. The halogenated metal compound also has the effect of crosslinking the water-soluble resin.

(chelating agent)

The water-soluble paint contains a chelating agent. The chelating agent is a material capable of forming a metal ion complex by coordinate bonding to a metal ion.

The chelating agent binds a metal compound (e.g., chromium oxide) derived from a halogenated metal compound to the water-soluble resin, and in order to improve the compressive strength of the first corrosion-prevention layer 13, the first corrosion-prevention layer 13 is not embrittled or peeled even when the thickness of the first corrosion-prevention layer 13 exceeds 0.2 μm and is not more than 1.0 μm, for example. Therefore, the adhesion strength between the stainless steel foil 14 and the first adhesive layer 12 and the adhesion strength between the stainless steel foil 14 and the layer on the upper layer side thereof can also be improved.

The chelating agent has a function of making the water-soluble resin resistant to hydration by chemically reacting with the water-soluble resin or the halogenated metal compound.

Examples of the chelating agent include aminocarboxylic acid chelating agents, phosphonic acid chelating agents, hydroxycarboxylic acid chelating agents, and (poly) phosphoric acid chelating agents.

Examples of aminocarboxylic acid chelating agents include nitrilotriacetic acid (NTA), hydroxyethyliminodiacetic acid (HIDA), ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), diethylenetriaminepentaacetic acid (DTPA), triethylenetetraminehexaacetic acid (TTHA), trancyclohexylenediaminetetraacetic 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-hydroxypropanetetraacetic acid (DPTA-OH), ethyleneglycoldiaminetetraacetic acid (GEDTA), ethylenediamine o-hydroxyphenylacetic acid (EDHPA), SS-ethylenediamine disuccinic acid (SS-EDDS), ethylenediamine disuccinic acid (EDDS), β -Alanine Diacetic Acid (ADA), glycine-methylglycine diacetate (MGDA), N-methylglycine diacetate (N-methylglycine (N-EDDA), N ' -phenylenediacetic acid (N ' -iminodiacetic acid (N, N ' -EDDA).

As phosphinesThe acid chelating agent is any acid chelating agent as long as it is composed of phosphonic acid (HP (= O) (OH) ₂ ) derivatized-P (= O) (OH) ₂ The compound having a structure is not particularly limited, and examples thereof include N, N-trimethylene phosphonic acid (NTMP), 1-hydroxyethylene-1,1-diphosphonic acid (HEDP), ethylenediamine-N, N' -tetramethylene phosphonic acid (EDTMP), diethylenetriamine pentamethylene phosphonic acid (DTPMP), 2-phosphonic acid butane-1,2,4-tricarboxylic acid (PBTC), nitrilotris (methylene phosphonic acid) (NTMP).

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

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

As general chelating agents available on the market, for example CHELEST PD-4H (PDTA) amino carboxylic acid chelating agent; phosphonic acid chelating agents (all chelating agents manufactured by CHELEST, inc., identified by trade name) such as CHELEST PH-540 (EDTMP), CHELEST PH-210 (HEDP), CHELEST PH-320 (NTMP), CHELEST PH-430 (PBTC).

Among them, chelating agents are preferably phosphoric acid chelating agents (phosphoric acid compounds) such as phosphonic acid chelating agents and (poly) phosphoric acid chelating agents, and phosphonic acid chelating agents are more preferably used.

The water-soluble resin is preferably 3 to 30% by mass, more preferably 5 to 20% by mass, and still more preferably 10 to 15% by mass of the total solid content of the water-soluble coating material. In addition, 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 entire 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, and still more preferably 35 to 45% by mass of the total solid content of the water-soluble coating material.

The water-soluble paint can be produced by dissolving a water-soluble resin, a halogenated metal compound, and a chelating agent in a solvent containing water. As the solvent, water is preferred.

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, and can be generally set to 0.1 to 10 mass%.

The thickness of the first corrosion prevention layer 13 is preferably 0.05 μm or more, and more preferably more than 0.1 μm. By setting the thickness of the first corrosion prevention layer 13 to 0.05 μm or more, the adhesion strength between the stainless steel foil 14 and the first adhesive layer 12 and the adhesion strength between the stainless steel foil 14 and the first base material layer 11 can be improved while imparting sufficient corrosion resistance to the battery exterior laminate 10.

The thickness of the first corrosion prevention layer 13 is preferably 1.0 μm or less, and 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 adhesion strength between the stainless steel foil 14 and the first adhesive layer 12 can be improved, 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, austenitic, ferritic, martensitic, or other stainless steel. Examples of austenite include SUS304, 316, and 301, while examples of ferrite include SUS430, and examples of martensite include SUS 410.

The stainless steel foil 14 has higher mechanical strength such as puncture strength and tensile strength than other metal foils such as aluminum foil, and therefore, when the thickness is 40 μm or less, sufficient mechanical strength can be imparted to the battery exterior laminate 10. As a result, the stainless steel foil 14 and the laminate 10 can be made thinner as a whole.

Further, since the mechanical strength is high, when the concave portion is formed by drawing, generation of a pinhole (pin hole) can be reduced, and as a result, leakage of the sealed contents in the laminated body (for example, leakage of a battery fluid) can be reduced. Further, since the stainless steel foil 14 is excellent in corrosion resistance as compared with other metal foils, deterioration due to corrosion can be prevented well.

The thickness of the stainless steel foil 14 is preferably 100 μm or less, preferably 5 to 40 μm, more preferably 5 to 30 μm, and particularly preferably 10 to 20 μm. By setting the lower limit value or more, the laminate 10 for battery exterior packaging is given sufficient mechanical strength, and when used in a battery such as a secondary battery, the durability of the battery can be improved. Further, by setting the thickness of the stainless steel foil 14 to the above upper limit or less, the battery exterior laminate 10 can be made sufficiently thin and can be given sufficient drawing workability.

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 adhesive or an epoxy adhesive. The thickness of the second adhesive layer 17 can be set to 0.5 to 10 μm, for example. By setting the thickness in this range, the second base material layer 15 and the stainless steel foil 14 can be bonded with high adhesion, and delamination can be prevented.

The second substrate layer 15 is not particularly limited as long as it has sufficient mechanical strength, and for example, polyester resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT); polyamide resins such as nylon (Ny); olefin resins such as stretched polypropylene (OPP); synthetic resin films made of polyether ether ketone (PEEK), polyphenylene sulfide (PPS), and the like. Among them, a PET film is preferable.

The thickness of the second substrate layer 15 may be, for example, 1 to 50 μm, preferably 1 to 30 μm, and more preferably 3 to 11 μm.

The second substrate layer 15 may have a single-layer structure or a multi-layer structure. As an example of the second substrate layer 15 having a multilayer structure, a two-layer film in which a polyethylene terephthalate (PET) resin film is laminated on a twin-screw stretched polyamide resin film (ONy) can be cited. The second base material layer 15 may have a multilayer structure in which 3 or more films are stacked.

In the embodiment shown in fig. 1, the second base material layer 15 is an outermost layer. Therefore, the second base material layer can have a desired color and design by containing a resin and a coloring agent such as a pigment.

The second substrate layer 15 is preferably composed of a single layer or a multilayer film using a heat-resistant resin film having a melting point of 200 ℃. Examples of such a heat-resistant resin film include a PET film, a PEN film, a PBT film, a nylon film, a PEEK film, and a PPS film, and a 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 improved, and the durability of a battery using the battery exterior laminate 10 can be improved.

In the battery exterior laminate 10 shown in fig. 1, the first corrosion-resistant layer 13 and the second corrosion-resistant layer 16 are formed on both surfaces of the stainless steel foil 14, and the first base material layer 11 side that can be brought into contact with an electrolytic solution or the like is defined as the inner surface side in the battery exterior using the battery exterior laminate 10. Therefore, the corrosion prevention layer is formed at least on the first base material layer 11 side of the stainless steel foil 14. That is, the second corrosion prevention layer 16 may be omitted 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 may be formed on the outer surface side of the second base material layer 15.

The coating layer (first coating layer) is formed of at least one resin selected from the group consisting of urethane resins, acrylic resins, polyvinylidene chloride, vinylidene chloride-vinyl chloride copolymer resins, maleic anhydride-modified polypropylene resins, polyester resins, epoxy resins, phenol resins, phenoxy resins, fluorine resins, cellulose ester resins, cellulose ether resins, polyamide resins, polyphenylene ether resins (PPE), polyphenylene sulfide resins (PPS), polyarylether resins (PAE), and polyetheretherketone resins (PEEK). 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 film cured layer formed by coating and drying a solvent-based coating prepared by dissolving the resin in a common organic solvent.

The formation of the coating layer can improve the insulation properties of the battery exterior laminate 10 and prevent the surface of the battery exterior laminate 10 from being damaged. Further, even when the battery exterior laminate 10 contacts the electrolyte solution, changes in appearance (discoloration and the like) can be prevented.

Further, the coating layer can be colored by adding a colorant and a pigment to the solvent-based coating material forming the coating layer. Further, coloring and printing may be added to the coating layer to display characters, graphics, images, patterns, and the like on the coating layer, thereby improving the design feeling.

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 directly bonded, but a printed layer for improving the design feeling may be provided on the inner surface side of the second base material layer 15.

The printed layer may have the same structure as the coated layer.

The thickness of the laminate 10 for battery exterior packaging is preferably 10 to 500. Mu.m, more preferably 20 to 200. Mu.m, and still more preferably 30 to 100. Mu.m.

Examples of the battery using the laminate 10 for battery exterior packaging include secondary batteries such as lithium ion batteries as secondary batteries, and capacitors such as electric double layer capacitors using an organic electrolyte as an electrolyte solution. The organic electrolyte is usually a medium of carbonates such as Propylene Carbonate (PC), ethylene carbonate (DEC), and ethylene carbonate, but is not particularly limited thereto.

The laminate for battery exterior packaging of the present invention can be produced, for example, by a method comprising the steps of: forming a first anti-corrosion layer on one surface of a stainless steel foil; forming a first adhesive layer on the formed first anti-corrosion layer; and a step of laminating the laminate by disposing the first base material layer in contact with the formed first adhesive layer.

The details will be described below.

First, the first corrosion prevention layer 13 is formed on one surface of the stainless steel foil 14.

Specifically, the water-soluble paint is applied to the surface of the stainless steel foil 14, and then heated and dried. In this case, only the first corrosion prevention layer 13 may be formed by applying the water-soluble paint to only one surface of the stainless steel foil 14, or the second corrosion prevention layer 16 may be formed simultaneously by applying the water-soluble paint to both surfaces of the stainless steel foil 14. In the case where the second corrosion prevention layer 16 is provided, the second corrosion prevention layer 16 is preferably formed at a stage before the first adhesive layer 12 and the like are formed, and more preferably formed simultaneously with the first corrosion prevention layer 13.

When the first corrosion prevention layer 13 and the second corrosion prevention layer 16 are formed at the same time, it is preferable that the stainless steel foil 14 is immersed in a water-soluble paint, the water-soluble paint is attached to both surfaces of the stainless steel foil 14, and then the resultant is dried by heating.

Next, the first adhesive layer 12 is formed on the first corrosion prevention layer 13.

Specifically, a layer made of the adhesive is formed on the surface of the stainless steel foil 14 on which the first corrosion prevention layer 13 is provided, and is heated and dried as needed.

When the adhesive is an adhesive for thermal lamination containing no organic solvent, the component (a) and the component (B) are melt kneaded to react the two components, and then the resultant mixture is applied to the first corrosion-resistant layer 13 and dried to form the first adhesive layer 12.

The melt kneading may be carried out by a known apparatus such as a single-screw extruder, a multi-screw extruder, a Banbury mixer, a plastomill (plastomill) or a heated roll kneader. In order to suppress decomposition of the epoxy group during melt kneading, it is preferable that volatile components such as moisture which can react with the epoxy group are removed in advance outside the apparatus, and when volatile components are generated during the reaction, they are discharged outside the apparatus at any time by deaeration or the like. When the acid-modified polyolefin resin has an acid anhydride group as an acid functional group, the reactivity with an epoxy group is high, and the reaction can be performed under more stable conditions, and therefore, the acid-modified polyolefin resin is preferable. The heating temperature at the time of melt kneading is preferably selected from the range of 240 to 300 ℃ in order to sufficiently melt the two components without thermally decomposing the components. The kneading temperature can be measured by a method such as bringing a thermocouple into contact with the adhesive resin composition in a molten state immediately after extrusion from the melt kneading apparatus.

In the case where the adhesive is an adhesive for dry lamination containing an organic solvent, the first adhesive layer 12 is formed by dissolving the component (a) and the component (B) in the organic solvent, applying the solution on the first corrosion-resistant layer 13, and drying the applied solution. The formation of the first adhesive layer 12 can be performed as a series of steps together with the step of laminating the first base material layer 11 described later using a known dry laminator or the like.

Then, the laminate is laminated by disposing the first base material layer 11 so as to be in contact with the formed first adhesive layer 12. The lamination is preferably dry lamination at 70 to 150 ℃. The pressure at the time of dry lamination is preferably 0.1 to 0.5MPa.

Specifically, a film constituting the first base material layer 11 is prepared in advance, and the film is disposed on the first adhesive layer and then dry-laminated. The temperature for dry lamination 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 bonded via the first adhesive layer, and may be determined in consideration of the material or melting point of the adhesive constituting the first adhesive layer 12. The temperature during dry lamination is generally 70 to 150 ℃, preferably 80 to 120 ℃.

In the laminate for battery exterior packaging of the present invention, 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, so that the dry lamination described above can be used for bonding. Then, by replacing the thermal lamination requiring heating exceeding 200 ℃ in the lamination with the dry lamination, the temperature at the lamination can be greatly reduced.

Generally, when a high temperature is applied to a stainless steel foil which has low thermal conductivity and is difficult to expand, the stainless steel foil is likely to be deformed (curled) in the width direction thereof. When such stainless steel foils are thermally laminated, heat may not be sufficiently transmitted in the plane, a portion not in contact with the thermocompression bonding roller may be generated in the width direction without being in contact with the roller, and bending and wrinkling may occur due to deformation itself at the time of thermocompression bonding. Further, when the stainless steel foil is heated to a high temperature at which deformation does not occur, productivity is lowered due to a reduction in processing speed or an increase in required heat.

Therefore, when dry lamination is employed for the production of the battery exterior laminate of the present invention, it is possible to suppress the occurrence of folding and wrinkles, and to produce a suitable battery exterior laminate.

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

The method for forming the second anticorrosive layer 16, the second adhesive layer 17, and the second base material layer 15 is not particularly limited, and for example, the second adhesive layer 17 is formed in advance as a laminate composed of two layers on the second base material layer 15. 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 were dry-laminated so that the second adhesive layer 17 was in contact with the second corrosion prevention layer 16, whereby the battery exterior laminate 10 having 7 layers was produced.

While one embodiment of the present invention has been described above with reference to the battery exterior laminate 10 shown in fig. 1, the technical scope of the present invention is not limited to the above-described embodiment, and various modifications may be made without departing from the scope of the present invention.

For example, the second corrosion prevention layer 16 may not be provided, and a 6-layer structure may be obtained.

Further, another layer may be provided on the side of the first base material layer 11 not in contact with the first adhesive layer 12 and on the side of the second base material layer 15 not in contact with the second adhesive layer 17, so that the structure may be 7 or more layers and 8 or more layers.

[ Battery outer covering body ]

A battery exterior package according to a second aspect of the present invention is a battery exterior package including the battery exterior laminate according to the first aspect, and has an internal space for housing a battery, and a side of the first base material layer of the battery exterior laminate is a battery exterior package on a side of the internal space. Specifically, the laminate for battery exterior packaging according to the first aspect is molded into a desired shape so that the first base layer faces the internal space, and the end portions are sealed as needed.

The shape, size, and the like of the battery exterior body are not particularly limited, and may be appropriately determined according to the type of battery used.

The battery exterior package may be formed of one member, or may be formed by combining two or more members (e.g., a container body and a lid) as described below with reference to fig. 2.

[ Battery ]

A battery according to a third aspect of the present invention has the battery exterior package of the second aspect.

Examples of the battery include secondary batteries such as lithium ion batteries as secondary batteries, and batteries using an organic electrolyte as an electrolytic solution such as capacitors such as electric double layer capacitors.

As an example, a perspective view of the secondary battery 40 is shown in fig. 2. The secondary battery 40 includes a lithium ion battery 27 in the battery outer container 20.

The battery exterior container 20 is formed by stacking the container body 30 comprising the battery exterior laminate 10 according to the first aspect of the present invention and the lid 33 comprising the battery exterior laminate 10, and heat-sealing the peripheral edge 29. Reference numeral 28 denotes electrode leads connected to the positive electrode and the negative electrode of the lithium ion battery 27.

The battery shown in fig. 2 may be manufactured in the following manner.

First, as shown in fig. 3 (a), the battery exterior laminate 10 is formed into a disk shape having a concave portion 31, and is molded by drawing or the like to obtain a container body 30. The depth of the recess 31 may be, for example, 2mm or more.

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

Next, as shown in fig. 3 (b), a lid 33 formed of the laminate 10 for battery exterior packaging is superimposed on the container body 30, and the flange (flange) portion 32 of the container body 30 and the peripheral edge portion 34 of the lid 33 are heat-sealed to obtain the secondary battery 40 shown in fig. 2. That is, in the battery shown in fig. 3, the lid 33 is covered on the upper surface of the container body 30, and the recess 31 and the lid 33 form an internal space for storing the battery.

Further, the battery of the present invention can also be manufactured as follows.

First, as shown in fig. 4 (a), a portion of one end side in the longitudinal direction of the rectangular battery exterior laminate 50 is pressed from the first base material layer side of the battery exterior laminate 50 by drawing molding or the like, and a molded body 55 having a concave portion 51 is obtained. The depth of the recess 51 may be, for example, 2mm or more.

Next, illustration is omitted, and a lithium ion battery (lithium ion battery 27 in fig. 2) is housed in the recess 51 of the molded body 55.

Next, a fold line L extending in the short side direction of the molded body 55 is formed in a part of the molded body 55 on the other end side where the recess 51 is not formed, and the molded body is bent on the side of the first base material layer. In this case, in the molded body 55, the region on the side of the recess 51 with respect to the folding line L is referred to as a "first region 551", and the region on the opposite side of the recess 51 with respect to the folding line L is referred to as a "second region 552".

Next, the first base material layer in the periphery 52 of the recess 51 in the first region 551 and the first base material layer (peripheral edge portion 54) overlapping the periphery 52 in the second region 552 are superimposed. Thereby overlapping the second region 552 on the concave portion 51 of the first region 551.

Next, as shown in fig. 4 (b), the secondary battery 60 having the battery exterior package composed of one member is obtained by heat-sealing the first base material layer around the concave portion 51 and the first base material layer of the second region 552. That is, in the battery shown in fig. 4 (b), the second region 552 covers the upper surface of the recess 51, so that an internal space for accommodating the battery is formed by the recess 51 and the second region 552.

Examples

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

Examples 1 to 15 and comparative examples 1 to 5

(examples 1 to 5)

First, a stainless steel foil having a thickness of 20 μm was prepared. Water-soluble paint (coating weight 12 g/m) is coated on both sides of the stainless steel foil ² ) The coating was dried by heating in an oven at 200 ℃ to form a first anticorrosive layer and a second anticorrosive layer each having a thickness shown in Table 1.

The water-soluble coating is prepared by mixing 0.2 mass% of non-crystalline polymer containing polyvinyl alcohol skeleton and having hydroxyl group, and 0.8 mass% of FeCl ₂ ·4H ₂ O and 0.7 mass% nitrilotris (methylenephosphonic acid) (trade name: CHELEST PH-320, manufactured by CHELEST Co., ltd.) were dissolved in water to prepare an aqueous solution.

Then, a first adhesive was applied to the first corrosion-resistant layer thus formed to form a first adhesive layer having a thickness of 3 μm. The first adhesive was obtained by melt-kneading 100 parts by mass of maleic anhydride-modified polypropylene (melting point 15 ℃ C.) and 7 parts by mass of novolac epoxy resin (product name: jER157S70, viscosity =80, epoxy equivalent =210, manufactured by Mitsubishi chemical corporation) in toluene at room temperature for 10 minutes.

The first adhesive layer and the first base material layer composed of a polypropylene resin film having a thickness of 6 μm in the laminate containing the stainless steel foil were laminated by dry lamination at 120 ℃.

The second base material layer was formed by coating a second adhesive layer (thickness: 3 μm) comprising a urethane adhesive (main agent: TM-K55 (trade name, manufactured by Toyo MOISTON Co., ltd.), curing agent: CAT-10L (trade name, manufactured by Toyo MOISTON Co., ltd.) on a second base material layer comprising a black stretched polyethylene terephthalate (PET) resin film having a thickness of 6 to 8 μm.

The second adhesive layer was laminated on the second anti-corrosion layer in the laminate obtained above at 80 ℃ by dry lamination to obtain a laminate for battery exterior packaging.

The surface defects of the obtained laminate for battery exterior packaging were visually observed and evaluated under the following evaluation conditions. The results are shown in Table 1 as "surface defects".

A: every 1m ² No 1 in-plane defect was observed.

B: every 1m ² 1 to 5 in-plane defects were observed.

C: every 1m ² 6 to 10 in-plane defects were observed.

D: every 1m ² More than 11 in-plane defects were observed.

3g of an electrolyte (1 mol/liter with LiPF added thereto) was prepared ₆ Ethylene carbonate, diethyl carbonate, dimethyl carbonate = 1) was filled into the outside of the batteryThe resulting three-sided sealed bag (inner size 30 mm. Times.50 mm, heat-seal width 7 mm) was filled with the laminate. The three-sided sealed bag was allowed to stand in a thermostatic bath at 85 ℃ for 2000 hours.

After 2000 hours, the three-sided sealed bag was opened, and the presence or absence of peeling of the layer on the inner side of the metal foil was visually observed, and evaluated according to the following evaluation criteria. The results are shown in table 1 as "electrolyte resistance".

A: no peeling was confirmed

B: slight peeling was confirmed but within the allowable range

C: confirmation of peeling

D: complete stripping

The test piece immersed in the electrolyte solution was immersed in pure water for 10 hours, and then taken out of the pure water, and the state was visually observed. The results of evaluation using the following evaluation criteria are shown in table 1 as "after water immersion".

A: no peeling was confirmed

B: slight peeling was confirmed but within the allowable range

C: confirmation of peeling

D: complete stripping

The laminate for battery exterior packaging was cut out in a size of 200mm × 100mm to obtain test pieces. The test piece was placed in a cold forming apparatus of 100mm × 50mm size, and embossed under a condition of 6mm in drawing depth. The generation of cracks and pinholes (pin holes) in the molded tensile section was observed by visual observation or an optical microscope. The same test was carried out 10 times, and the results of evaluation using the following evaluation criteria are shown in table 1 as "moldability".

A: the molding stretch portion did not break or generate a pinhole.

B: the samples in which a slight breakage or pinhole was generated within an allowable range in the molding stretch portion were 1 to 3 samples out of 10 samples.

C: the samples in which a small amount of breakage or pin holes occurred in the molding and stretching portion were 1 to 5 out of 10 samples.

D: the samples in which large-scale breakage occurred in the molding and stretching portion or pinholes occurred were 6 or more out of 10 samples.

(examples 6 to 10)

A battery exterior laminate was produced in the same manner as in example 3, except that the adhesive shown in table 1 was used as the first adhesive for forming the first adhesive layer, and the same evaluation as in example 1 was performed. The results are shown in Table 1.

(example 11)

A laminate for battery exterior packaging was produced in the same manner as in example 3, except that the dry lamination of the first adhesive layer and the first base material layer at 120 ℃ was changed to the thermal lamination at 200 ℃, and the same evaluation as in example 1 was performed. The results are shown in Table 1.

(example 12)

A laminate for battery exterior packaging was produced in the same manner as in example 3, except that the first base material layer was changed from a block PP film to a random PP film, and the same evaluation as in example 1 was performed. The results are shown in Table 1.

(examples 13 to 14)

A laminate for battery exterior packaging was produced in the same manner as in example 3, except that the stainless steel foil having a thickness of 20 μm was changed to the stainless steel foil having a thickness shown in table 1, and the same evaluation as in example 1 was performed. The results are shown in Table 1.

(example 15)

A laminate for battery exterior packaging was produced in the same manner as in example 1 except that the first and second corrosion-prevention layers were subjected to chromium fluoride plating treatment to obtain first and second corrosion-prevention layers having a thickness of 250 μm, and the same evaluation as in example 1 was performed. The results are shown in Table 1.

Comparative example 1

A laminate for battery exterior packaging was produced in the same manner as in example 11, except that an aluminum foil having a thickness of 20 μm was used as the metal foil instead of the stainless steel foil, and an adhesive having only maleic anhydride-modified polypropylene (melting point 80 ℃) and no novolac epoxy resin was used as the first adhesive, and the same evaluation as in example 1 was performed. The results are shown in Table 1.

Comparative example 2

0.8 mass% of CrF was used except that an aluminum foil having a thickness of 20 μm was used as the metal foil instead of the stainless steel foil ₃ ·3H ₂ O replaces 0.8 mass% FeCl of the first and second anti-corrosion layers ₂ ·4H ₂ Except for O, a laminate for battery exterior packaging was produced in the same manner as in example 3, and the same evaluation as in example 1 was performed. The results are shown in Table 1.

Comparative example 3

A laminate for battery exterior packaging was produced in the same manner as in example 3, except that an adhesive having only maleic anhydride-modified polypropylene (melting point 80 ℃) and no novolac epoxy resin was used as the first adhesive, and the same evaluation as in example 1 was performed. The results are shown in Table 1.

Comparative example 4

A battery exterior laminate was produced in the same manner as in example 1, except that the first corrosion-resistant layer and the second corrosion-resistant layer were not provided, and the same evaluation as in example 1 was performed. The results are shown in Table 1.

Comparative example 5

[ Table 1]

In table 1, each ellipsis has the following meaning.

(bPP): block polypropylene

(rPP): atactic polypropylene

(Ad-NV 1): a toluene solution adhesive containing 100 parts by mass of maleic anhydride-modified polypropylene (melting point: 80 ℃ C.) and 5 parts by mass of novolac epoxy resin (product name: jeR154, epoxy equivalent =178, mitsubishi chemical corporation) and having a solid content of 15%

(Ad-NV 2): a toluene solution adhesive having a solid content of 15% and comprising 100 parts by mass of a maleic anhydride-modified polypropylene (melting point: 80 ℃) and 2 parts by mass of a novolak type epoxy resin jER154

(Ad-NV 3): a toluene solution adhesive having a solid content of 15% and comprising 100 parts by mass of a maleic anhydride-modified polypropylene (melting point: 80 ℃) and 7 parts by mass of a novolak type epoxy resin jER154

(Ad-NV 4): a toluene solution adhesive containing 100 parts by mass of maleic anhydride-modified polypropylene (melting point: 80 ℃) and 10 parts by mass of jER154 as a solid content, 15%

(Ad-NV 5): a toluene solution adhesive having a solid content of 15% and comprising 100 parts by mass of a maleic anhydride-modified polypropylene (melting point: 80 ℃) and 15 parts by mass of jER154 as a novolac epoxy resin

(Ad-NV 6): adhesive comprising 100 parts by mass of maleic anhydride-modified polypropylene (melting point: 140 ℃ C.) and 5 parts by mass of novolak type epoxy resin jER154

(Ad-BPNV): a toluene solution adhesive containing 100 parts by mass of maleic anhydride-modified polypropylene (melting point: 80 ℃) and 5 parts by mass of a bisphenol A-structured epoxy novolac resin (product name: jeR157S70, viscosity =80; epoxy equivalent =210, manufactured by Mitsubishi chemical corporation) and having a solid content of 15%

(Ad-PN): an adhesive agent comprising 15% of a toluene solution containing 100 parts by mass of a maleic anhydride-modified polypropylene (melting point: 80 ℃) and 5 parts by mass of a phenoxy resin (product of Mitsubishi chemical corporation, trade name: epikote 1001, epoxy equivalent = 450)

(Ad-PP): adhesive containing 100 parts by mass of maleic anhydride-modified polypropylene (melting point 140 ℃ C.)

(SUS): stainless steel foil

(AL): aluminum foil

As is clear from the results shown in table 1, the battery exterior laminates of examples 1 to 15 were able to suppress the occurrence of surface defects, were able to reduce peeling even when exposed to an electrolytic solution or water, had good moldability, and had excellent properties (processability, moldability, mechanical strength, chemical resistance, and water resistance) as compared with the battery exterior laminates of comparative examples 1 to 5.

[ examples 16 to 24]

In example 3 described above, 0.8 mass% of the halogenated metal shown in table 2 was used in place of 0.8 mass% of FeCl in the first corrosion prevention layer and the second corrosion prevention layer ₂ ·4H ₂ Examples 16 to 24 were examined. The evaluation method and evaluation criteria were the same as in example 1. The results are shown in Table 2.

[ Table 2]

	Halogenated metals	Surface defect	Resistance to electrolyte solution	After water immersion	Formability
						Example 16	FeF ₃	B	A	B	A
Example 17	MnF ₃	B	A	B	A
						Example 18	MnCl ₂	B	B	B	A
Example 19	CrF ₃	B	A	B	A
						Example 20	CrCl ₃	B	B	B	A
Example 21	ZrCl ₃	B	B	B	A
						Example 22	TiCl ₄	B	B	B	A
Example 23	CaCl ₂	B	C	C	A
						Example 24	AlCl ₄	B	C	C	A

From the results shown in table 2, it was confirmed that the effects of the present invention can be obtained even when various compounds are used as the halogenated metal compound.

Claims

1. A laminate for battery outer packaging, comprising at least a first base material layer, a first adhesive layer, a first anticorrosive layer, a stainless steel foil, and a second base material layer in this order,

the first substrate layer is a layer composed of block polypropylene,

the first adhesive layer is a dry lamination adhesive layer composed of an adhesive containing only 100 parts by mass of maleic anhydride modified polypropylene (A) with a melting point of 50-100 ℃ and 2-7 parts by mass of compound (B) with a plurality of epoxy groups as solid components,

the compound (B) having a plurality of epoxy groups is a bisphenol A novolac epoxy resin having an epoxy equivalent of 100 to 300g/eq represented by the following general formula (1),

[ chemical formula 1]

In the formula (1), R ¹ ～R ⁶ Each independently is a hydrogen atom or a methyl group, n is an integer of 0 to 10, R ^X Is an epoxy group or a glycidyl group,

the first anti-corrosion layer contains, in all solid components, only 3 to 30 mass% of a resin having a polyvinyl alcohol skeleton, 20 to 60 mass% of a chloride of iron, manganese or zirconium or a fluoride of iron, manganese or zirconium, and 20 to 60 mass% of a phosphoric acid compound,

the phosphoric acid compound is one or more selected from the group consisting of 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), ethylenediamine-N, N, N ', N' -tetramethylenephosphonic acid (EDTMP), diethylenetriamine pentamethylenephosphonic acid (DTPMP), 2-phosphonic acid butane-1,2,4-tricarboxylic acid (PBTC), and nitrilotris (methylenephosphonic acid) (NTMP),

the first anti-corrosion layer has a thickness of more than 0.1 μm and 0.5 μm or less,

the thickness of the stainless steel foil is 20-30 mu m.

2. A battery exterior body comprising the battery exterior laminate according to claim 1,

the battery exterior body has an internal space for housing a battery, and the first base material layer side of the battery exterior laminate is the internal space side.

3. A battery comprising the battery exterior according to claim 2.