Lithium-ion secondary battery casing material

Abstract

The present invention provides a lithium-ion secondary battery casing material having a protective layer that exhibits electrolyte resistance even during the formation process under relatively low temperature conditions. [Solution] A lithium-ion secondary battery exterior material having a laminated structure comprising a protective layer, a base layer, and a barrier layer in that order, wherein the protective layer contains a polyolefin resin (A) and an organic titanium compound (B), and the titanium content in the protective layer is 0.5 to 20% by mass. The exterior material is formed by applying a coating solution containing a polyolefin resin (A), an organic titanium compound (B), and a liquid medium to the base layer and then drying it.

Description

Technical Field

[0001] The present invention relates to an exterior material for a lithium-ion secondary battery.

Background Art

[0002] As a battery for consumer use such as used in portable terminals such as personal computers and mobile phones, a lithium-ion battery that can be made thinner and smaller has been developed. As an exterior material for a lithium-ion battery, a multilayer laminate film has been used because it is lighter than conventional metal materials and can be freely designed in shape. In addition, exterior materials using such a laminate film have not only a high degree of design freedom but also are lightweight and low-cost, so their application to batteries for hybrid vehicles and electric vehicles with a small environmental load has also been tried. As the structure of the laminate film, a sealant layer is laminated via an adhesive layer on one surface of a metal foil layer such as an aluminum foil, and a base material layer (PET film) is laminated via an adhesive layer on the opposite surface. This configuration is common. In recent years, as an exterior material for a lithium-ion secondary battery, a laminate in which a polyamide resin layer / aluminum foil layer / sealant layer are laminated in this order has been used. The exterior material is processed into a container shape by deep drawing so that the polyamide resin layer side of the laminate is on the outside of the battery and the sealant layer side is on the inside (inside the battery), and a battery electrolyte (hereinafter referred to as electrolyte) is injected into the battery.

[0003] As the electrolyte, an electrolyte in which a lithium salt is dissolved in an aprotic solvent (propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, etc.) is used.

[0004] The base layer is generally formed from a thermoplastic resin film, and since contact with the electrolyte causes surface whitening and deterioration of physical properties, lithium-ion secondary battery casing materials have been proposed that have a protective layer against the electrolyte on the outside of the base layer. For example, Patent Document 1 describes a protective layer made of a polyamide resin film prepared from a combination of acid-modified polyolefin, polyvinyl alcohol, and a crosslinking agent. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2018-060765 [Overview of the project] [Problems that the invention aims to solve]

[0006] The protective layer described in Patent Document 1 was formed by coating an unstretched polyamide resin film with a coating agent, and then applying sufficient heat to the coating during in-line stretching of the film to achieve its protective layer performance. However, if a company does not have film production equipment capable of such in-line coating, it is necessary to purchase a stretched film and form the protective layer from there. In such cases of protective layer formation by so-called off-line coating, due to limitations in the performance of the drying oven and the heat resistance of the sealant layer, heat treatment can only be applied at a maximum of about 130°C, and therefore sufficient electrolyte resistance cannot always be achieved.

[0007] The object of the present invention is to provide a lithium-ion secondary battery exterior material having a protective layer that exhibits electrolyte resistance even when formed under relatively low temperature conditions. [Means for solving the problem]

[0008] As a result of diligent research, the inventors of the present invention discovered that a protective layer comprising a polyolefin resin and an organotitanium compound can solve the above-mentioned problems, and thus arrived at the present invention.

[0009] In other words, the gist of this invention is as follows: <1> A lithium-ion secondary battery casing material having a laminated structure comprising a protective layer, a base layer, and a barrier layer in that order, wherein the protective layer comprises a polyolefin resin (A) and an organic titanium compound (B), and the titanium content in the protective layer is 0.5 to 20% by mass. <2> The organotitanium compound (B) is a chelate-type organotitanium compound. <1> The lithium-ion secondary battery casing material described. <3> The chelate-type organotitanium compound is titanium diisopropoxybis(triethanolamine) or titanium diethanolamine. <1> ~ <3> Lithium-ion secondary battery casing material as described in one of the following. <4> The base layer is a polyamide film. <1> The lithium-ion secondary battery casing material described. <5> The barrier layer is a metal foil or a metal vapor-deposited film. <1> The lithium-ion secondary battery casing material described. <6> The process includes a step of applying a coating solution containing a polyolefin resin (A), an organotitanium compound (B), and a liquid medium to a substrate layer, and then drying it to form a protective layer. <1> A method for manufacturing the exterior material of a lithium-ion secondary battery. <7> The drying temperature is 130°C or lower. <6> A method for manufacturing the exterior material of a lithium-ion secondary battery. [Effects of the Invention]

[0010] The lithium-ion secondary battery casing material of the present invention is resistant to electrolytes, and the above effect can be obtained even with a thin film of 3 μm or less, under drying conditions of 130°C or less, such as offline conditions (heat treatment at 100-120°C). This makes it possible to reduce the cost of lithium-ion secondary battery casing materials. [Modes for carrying out the invention]

[0011] The present invention will be described in detail below. The lithium-ion secondary battery casing material of the present invention is a laminate in which at least a protective layer, a base layer, and a barrier layer are stacked in this order. In this invention, the protective layer side of the laminate may be referred to as the outside, and the barrier layer side as the inside.

[0012] The protective layer will now be described. The protective layer in this invention comprises a polyolefin resin (A) and an organotitanium compound (B).

[0013] The olefin component, which is the main component of the polyolefin resin, is not particularly limited, but alkenes having 2 to 6 carbon atoms, such as ethylene, propylene, isobutylene, 2-butene, 1-butene, 1-pentene, and 1-hexene, are preferred. Mixtures of these may also be used. Among these, alkenes having 2 to 4 carbon atoms, such as ethylene, propylene, isobutylene, and 1-butene, are more preferred, ethylene and propylene are even more preferred, and ethylene is the most preferred.

[0014] The organotitanium compound (B) in the present invention is not particularly limited, but examples include titanium alkoxide compounds such as tetran-butyl titanate, tetrastearyl titanate, tetrater-butyl titanate, tetraisopropyl titanate, tetraoctyl titanate, and butyl titanate dimer; titanium octylene glycolate, titanium lactate, titanium diethanolamine, titanium triethanolamine, titanium aminoethylaminoethanolate, titanium tetraacetylacetonate, titanium acetylacetonate, titanium ethylacetoacetate, titanium dodecylbenzenesulfonate compounds, titanium phosphate ester complexes, titanium lactate ammonium salts, and titanium acylate compounds such as titanium isostearate. Two or more of these may be included. Among these, chelated organotitanium compounds are preferred. Of the chelated organotitanium compounds, titanium triethanolamine and titanium diethanolamine are preferred.

[0015] Examples of commercially available organotitanium compounds include the "OrgaTix TA series" and "OrgaTix TC series" manufactured by Matsumoto Fine Chemical Co., Ltd.

[0016] The method for forming a protective layer containing a polyolefin resin (A) and an organotitanium compound (B) is not particularly limited, but a preferred method involves applying a coating solution containing the polyolefin resin, the organotitanium compound, and a liquid medium onto a substrate layer, and then removing the liquid medium by heating the resulting coating film. The drying temperature at this time is preferably 130°C or lower, more preferably 50 to 130°C, and even more preferably 100 to 120°C.

[0017] As a method for preparing the coating liquid, a method of obtaining it by adding an organic titanium compound to a solution or dispersion of a polyolefin resin (A) in a liquid medium is convenient. Examples of the liquid medium include water, hydrocarbon solvents such as toluene and cyclohexane, ester solvents such as ethyl acetate, ketone solvents such as methyl ethyl ketone, glycol solvents such as ethylene glycol, glycol ether solvents such as butyl cellosolve, ether solvents such as tetrahydrofuran, alcohol solvents such as methanol, and other organic solvents, as well as an aqueous medium obtained by mixing water and the organic solvent.

[0018] Examples of commercially available products of the solution or dispersion of the polyolefin resin (A) include Super Cron series (E-723, E-503, 822, 930, etc.) manufactured by Nippon Paper Chemicals Co., Ltd., Zicen series (Zicen A, Zicen L) manufactured by Sumitomo Seika Chemicals Co., Ltd., Arrow Base series (SB-1200, SD-1200, DA-1010) manufactured by Unitika Ltd., Chemipar series (S-100, S-75N, etc.) manufactured by Mitsui Chemicals, Inc., and the like.

[0019] In addition, a coating liquid can be prepared by dispersing or dissolving a commercially available polyolefin resin in the above-mentioned liquid medium so that the solid content concentration becomes 1 to 30% by mass. Examples of the commercially available polyolefin resin include Hiwax series (1105A, 2203A) manufactured by Mitsui Chemicals, Inc., Dia Carnal 30M manufactured by Mitsubishi Chemical Corporation, OX-1749 manufactured by Nippon Seiro Co., Ltd., Bondine series (HX-8290, LX-4110), Rotader series (3210, 4503), Toughmer XM series manufactured by Mitsui Chemicals, Inc., and the like.

[0020] When dispersing or dissolving the polyolefin resin (A) in an aqueous medium, it is preferable that it has an appropriate acid value. The acid value is preferably between 5 mg KOH / g and 150 mg KOH / g, and more preferably between 20 mg KOH / g and 140 mg KOH / g. If the acid value is less than 5 mg KOH / g, sufficient adhesion to the substrate may not be obtained. Furthermore, it tends to become difficult to disperse the acid-modified polyolefin resin in an aqueous medium or to dissolve it in an aqueous solution. On the other hand, if the acid value exceeds 150 mg KOH / g, the electrolyte resistance of the coating film tends to decrease.

[0021] The blending ratio of polyolefin resin (A) and organotitanium compound (B) in the protective layer must be such that the titanium content in the protective layer is 0.5 to 20% by mass, preferably 1 to 10% by mass, and more preferably 1.5 to 5% by mass. If the titanium content in the protective layer is less than 0.5% by mass, the electrolyte resistance will be poor, and if it exceeds 20% by mass, the adhesion to the substrate may be poor.

[0022] The protective layer may contain resins other than polyolefin resin or other additives (such as crosslinking agents), as long as they do not impair the effects of the present invention.

[0023] Examples of resins other than polyolefin resins include hydroxyl group-containing compounds such as polyvinyl alcohol, polyvinyl acetate, ethylene-vinyl acetate copolymer, polyvinyl chloride, polypyrinidene chloride, styrene-maleic acid resin, styrene-butadiene resin, butadiene resin, acrylonitrile-butadiene resin, poly(meth)acrylonitrile resin, (meth)acrylamide resin, chlorinated polyethylene resin, chlorinated polypropylene resin, polyester resin, urethane resin (polyether type, polyester type, polycarbonate type), nylon resin, phenolic resin, silicone resin, epoxy resin, and the like.

[0024] As crosslinking agents, self-crosslinking agents, compounds having multiple functional groups that react with carboxyl groups within the molecule, and metal complexes having polyvalent coordination sites can be used. Examples of these include melamine compounds, urea compounds, epoxy compounds, carbodiimide compounds, oxazoline compounds, zirconium salt compounds, and silane coupling agents.

[0025] The protective layer may contain, as needed, pigments or dyes, leveling agents, defoaming agents, anti-smudge agents, thickeners, pigment dispersants, UV absorbers, etc.

[0026] The thickness of the protective layer is not particularly limited, but is preferably 0.1 to 20 μm, more preferably 0.2 to 15 μm, even more preferably 0.3 to 10 μm, and particularly preferably 0.5 to 5 μm. If the thickness is less than 0.1 μm, the electrolyte resistance may deteriorate, and if it exceeds 20 μm, cracking of the protective layer may occur. Even if the protective layer is a thin film of 3 μm or less, and in some cases 1 μm or less, adhesion and electrolyte resistance can be obtained, making it possible to reduce the cost of lithium-ion secondary battery casing materials.

[0027] As a method for forming a protective layer using the aforementioned coating liquid, a uniform protective layer can be formed by uniformly coating the surface of various substrates using known film formation methods, such as gravure roll coating, reverse roll coating, wire bar coating, lip coating, air knife coating, curtain flow coating, spray coating, immersion coating, or brush coating. After setting the substrate at room temperature as needed, it can be subjected to drying or a heat treatment for drying and baking, thereby forming a uniform protective layer that adheres closely to the surface of various substrates. For the heating device at this time, a normal hot air circulation type oven or infrared heater can be used. The heating temperature can be used in the range of 50 to 200°C. In this invention, sufficient adhesion to the substrate and electrolyte resistance can be obtained when the protective layer is formed under drying conditions of 130°C or lower. Furthermore, an aging treatment may be performed at 60 to 80°C to advance the reaction.

[0028] The protective layer and the adjacent substrate layer are not particularly limited, and examples include films and molded articles of various thermoplastic resins. Since the protective layer in the invention provides excellent adhesion even with relatively low heat treatment, it can be applied to substrates with relatively low heat resistance, such as thermoplastic resins with a melting point of 180°C or lower, such as polyethylene and polypropylene.

[0029] Examples of thermoplastic resin films include films made from polyamide, flexible polyvinyl chloride resin film, polyethylene terephthalate, polyethylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate polyethylene succinate, polyglycolic acid, polylactic acid, polypropylene, polyethylene, polyurethane, polyimide resin, polycarbonate resin, polyarylate resin, ABS resin, acrylic resin, or mixtures thereof, or laminates of such films. From the viewpoint of deep drawing, polyamide film is preferred.

[0030] The thermoplastic resin film used as the base layer can be either an unstretched or stretched film, and the manufacturing method is not limited. The thickness is also not particularly limited, but typically ranges from 5 to 500 μm.

[0031] The base layer may contain a filler. Inorganic fillers are preferred, and examples include calcium carbonate, clay, silica, diatomaceous earth, talc, titanium dioxide, barium titanate, barium sulfate, and alumina.

[0032] It is preferable that one or both sides of the substrate layer be subjected to known surface treatments such as corona treatment, plasma treatment, or ozone treatment, and it is particularly preferable that the surface in contact with the protective layer be subjected to corona treatment.

[0033] The barrier layer in this invention is not particularly limited, and known metal foils or metal vapor-deposited films suitable for lithium-ion secondary battery casing materials, or combinations thereof, can be used. Examples of metal foils include aluminum foil, copper foil, nickel foil, and titanium foil. Examples of metal species for the metal vapor-deposited film include aluminum, alumina, silica, chromium, zinc, gold, silver, platinum, nickel, titanium oxide, zirconia, and magnesium fluoride. Furthermore, a film in which a metal vapor-deposited film is provided on a base film, such as an aluminum vapor-deposited PET film or an aluminum vapor-deposited nylon film, can be used as the base layer / barrier layer in this invention, and the metal vapor-deposited film can be used as the barrier layer. The thickness of the metal foil is preferably in the range of 20 to 200 μm, and more preferably 30 to 150 μm. A metal vapor-deposited film with a thickness of 10 to 1000 nm can be suitably used. The metal vapor-deposited film may also be further plated.

[0034] Preferably, one or both sides of the barrier layer are surface-treated to be resistant to electrolytes, and known surface treatment methods such as chemical conversion treatment and chromate treatment are examples. In particular, it is preferable that these surface treatments be applied to the side in contact with the sealant layer.

[0035] The lithium-ion secondary battery casing material of the present invention may have a sealant layer on the side opposite the base layer of the barrier layer. The sealant layer can be a known type suitable for lithium-ion secondary battery casing materials. Specifically, a polyolefin resin film can be used. Examples of polyolefin resins include polyethylene, polypropylene, copolymers mainly composed of these, and acid-modified products thereof. The polyolefin resin film can be either a stretched film or an unstretched film. Furthermore, two or more layers of polyolefin resin film may be provided. In addition, a functional sealant layer that provides barrier properties may be used as the sealant layer.

[0036] The thickness of the sealant layer is preferably in the range of 20 to 200 μm, and more preferably 30 to 10 μm. In addition, one or both sides of the sealant layer may be subjected to known surface treatments such as corona treatment, plasma treatment, or ozone treatment.

[0037] Next, we will explain the manufacturing method for lithium-ion secondary battery casing materials.

[0038] The lithium-ion secondary battery casing material of the present invention has a laminated structure comprising at least a protective layer / base layer / barrier layer in this order.

[0039] The method for laminating layers other than the protective layer, i.e., the base layer / barrier layer, can employ known methods suitable for the manufacture of lithium-ion secondary battery casing materials. Lamination may be carried out between each layer via known adhesives. For interlayer bonding of the base layer / barrier layer, for example, two-component urethane adhesives, polyester adhesives, or acid-modified polyolefin adhesives can be used. As for the method of laminating the polyamide film layer onto the aluminum foil layer, methods such as dry lamination or thermal lamination can be employed via the aforementioned adhesives. When the metal vapor-deposited film is used as the barrier layer, the metal vapor-deposited film may be laminated so that either the metal vapor-deposited film side or the film side faces the base layer.

[0040] When a sealant layer is provided, a two-component urethane-based adhesive or an acid-modified polyolefin-based adhesive can be used between the barrier layer and the sealant layer for interlayer bonding. Methods for laminating the sealant layer onto the barrier layer include dry lamination, heat lamination, extrusion lamination, and sandwich lamination using the aforementioned adhesives.

[0041] Between each of the protective layer, substrate layer, and barrier layer, anchor coat layers, primer layers, and other layers may be provided as needed, as long as they do not impair the effects of the present invention.

[0042] The lithium-ion secondary battery casing material of the present invention may have other functional layers laminated on the outside of the protective layer. The other functional layers are not particularly limited, and layers suitable for the required performance may be appropriately selected and provided within the limits that do not impair the effects of the present invention. Examples of other functional layers include a hard coat layer, an electrolyte leakage and tear prevention layer (LLDPE film layer), a metal corrosion prevention layer, and a shutdown layer (polyethylene nonwoven fabric or microporous film).

[0043] The lithium-ion secondary battery casing material of the present invention is also applicable to embossed and deep-drawn lithium-ion secondary batteries. [Examples]

[0044] The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. The various characteristics were measured or evaluated using the following methods.

[0045] 1. Characteristics of the protective layer In the following evaluations, the following materials were used as substrates: nylon film (Emblem ON, manufactured by Unitika, 15 μm thick, hereinafter referred to as "polyamide resin film"), stretched polypropylene film (manufactured by Mitsui Chemicals Tohcello, 25 μm thick, hereinafter referred to as "OPP film"), and flexible polyvinyl chloride film (Achilles Slip A, manufactured by Morimatsu, 80 μm thick, hereinafter referred to as "polyvinyl chloride film").

[0046] (1) Adhesion to substrate (tape peel test) After forming a protective layer with a thickness of 3 μm on the corona-treated surfaces of polyamide resin film and polyvinyl chloride film, TESA tape (TESA 7475 manufactured by Tesa Tape Co., Ltd.) was applied to the protective layer surface, and the degree of peeling when the tape was peeled off in one go was visually evaluated according to the following criteria. ○: No peeling at all △: Partial peeling ×: Completely peeled off

[0047] (2) Electrolyte resistance After forming a protective layer with a thickness of 1 μm on the corona-treated surfaces of the polyamide resin film and the vinyl chloride film, one drop of electrolyte (LBG-00015 LiPF6 (1 mol / L) manufactured by Kishida Chemical Co., Ltd., with solvent EC:DMC:DEC (1:1:1 v / v%)) was placed on the protective layer, and the OPP film was placed in close contact with the electrolyte-wet protective layer surface. After being left at room temperature for one day, it was visually evaluated according to the following criteria. ○: No change in the appearance of the substrate. △: Whitening of the substrate ×: Holes are made in the base material.

[0048] 2. Acid-modified polyolefin resin • Acid-modified polyolefin resin aqueous dispersion (E-1) Arrow Base SB-1200: Manufactured by Unitika Corporation (Solid content concentration 25% by mass) • Acid-modified polyolefin resin aqueous dispersion (E-2) Arrowbase SD-1200: Manufactured by Unitika Corporation (Solid content concentration 20% by mass) • Acid-modified polyolefin resin aqueous dispersion (E-3) Arrow Base DA-1010: Manufactured by Unitika Corporation (Solid content concentration 25% by mass) • Acid-modified polyolefin resin aqueous dispersion (E-4) Chemipearl S100: Manufactured by Mitsui Chemicals, Inc. (Solid content concentration 27% by mass) • Acid-modified polyolefin resin toluene solution (E-5) Supercron 822: Manufactured by Nippon Paper Industries (Solid content concentration 20% by mass) • Acid-modified polyolefin resin toluene solution (E-6) Highwax 1105A (manufactured by Mitsui Chemicals, low molecular weight polyolefin, acid-modified type) is dissolved in toluene to a solid content concentration of 2% by mass.

[0049] 3. Organotitanium compounds • Organotitanium compound (G-1) Titanium diisopropoxybis(triethanolamine) TC-400: Manufactured by Matsumoto Fine Chemical Co., Ltd. (Ti content: 8% by mass, chelate type) • Organotitanium compound (G-2) Titanium diethanolamine TC-500: Manufactured by Matsumoto Fine Chemical Co., Ltd. (Ti content: 8% by mass, chelate type)

[0050] 4. Crosslinking agent • Oxazoline compound (G-3) Nippon Shokubai Co., Ltd.'s Epocross WS-700 (an aqueous solution of an oxazoline compound containing 2-isopropenyl-2-oxazoline, with a solid content concentration of 25% by mass) was used. • Hydrazide compound (G-4) A 5% aqueous solution of dihydrazide adipic acid manufactured by Otsuka Chemical Co., Ltd. was used.

[0051] 5. Polyvinyl alcohol • Polyvinyl alcohol (P-1) We used VC-10 (10% by mass aqueous solution) manufactured by Nippon Vinegar Bi-Poval Co., Ltd.

[0052] Example 1 A coating solution was obtained by mixing 400 parts by mass of an aqueous dispersion of acid-modified polyolefin resin (E-1) and 6.25 parts by mass of an organotitanium compound (G-1) at room temperature (the mass ratio of acid-modified polyolefin solids to titanium was 100 / 0.5). This coating solution was applied to various substrates using a Meyer bar to a predetermined film thickness, and then dried at 100°C for 30 seconds to obtain a protective layer.

[0053] Examples 2-14, Comparative Examples 1-7 As shown in the table, a protective layer was obtained by performing the same procedure as in Example 1, except that the type of acid-modified polyolefin resin and the mass ratio of organotitanium compounds were changed so that the mass ratio of the acid-modified polyolefin solids to the titanium contained in the organotitanium compounds was as shown in the table.

[0054] Example 15 5000 parts by mass of an acid-modified polyolefin resin toluene solution (E-6) and 37.5 parts by mass of an organotitanium compound (G-1) were mixed at a liquid temperature of 50°C (the mass ratio of acid-modified polyolefin solids to titanium was 100 / 3) to obtain a coating solution. This coating solution, heated to 50°C, was applied to various substrates using a Meyer bar to a predetermined film thickness, and then dried at 100°C for 30 seconds to obtain a protective layer.

[0055] Example 16 Using the same coating solution as in Example 8, the solution was applied to various substrates using a Meyer bar to a predetermined film thickness, and then dried at 50°C for 30 seconds to obtain a protective layer.

[0056] The composition and properties of the coating agents in the examples and comparative examples are shown in the table.

[0057] [Table 1]

[0058] [Table 2]

[0059] [Table 3]

[0060] As shown in Examples 1 to 16, the protective layer containing an acid-modified polyolefin resin (A) and an organotitanium compound (B) exhibited excellent adhesion to the substrate and resistance to electrolytes due to the inclusion of the organotitanium compound (B).

[0061] Each comparative example had the following problems. The aqueous coating agents in Comparative Examples 1-3 did not contain organotitanium compound (B), and therefore exhibited poor electrolyte resistance. The aqueous coating agents in Comparative Examples 4 and 5 had poor electrolyte resistance because their content of organotitanium compounds was outside the specified range. The aqueous coating agent in Comparative Example 6 had poor substrate adhesion and electrolyte resistance because it used a crosslinking agent other than an organotitanium compound. Comparative Example 7, being a conventional protective layer, had poor resistance to electrolytes and poor resistance to electrolytes after storage.

Claims

1. A lithium-ion secondary battery casing material having a laminated structure comprising a protective layer, a base layer, and a barrier layer in that order, wherein the protective layer comprises a polyolefin resin (A) and an organic titanium compound (B), and the titanium content in the protective layer is 0.5 to 20% by mass.

2. The lithium-ion secondary battery casing material according to claim 1, wherein the organotitanium compound (B) is a chelate-type organotitanium compound.

3. The lithium-ion secondary battery casing material according to any one of claims 1 to 3, wherein the chelate-type organotitanium compound is titanium diisopropoxybis(triethanolamine) or titanium diethanolamine.

4. The lithium-ion secondary battery casing material according to claim 1, wherein the base layer is a polyamide film.

5. The lithium-ion secondary battery casing material according to claim 1, wherein the barrier layer is a metal foil or a metal vapor-deposited film.

6. A method for producing a lithium-ion secondary battery casing material according to claim 1, comprising the step of applying a coating solution containing a polyolefin resin (A), an organotitanium compound (B), and a liquid medium to a substrate layer, and then drying it to form a protective layer.

7. A method for manufacturing a lithium-ion secondary battery casing material according to claim 6, wherein the drying temperature is 130°C or lower.

Images