JP5316793B2 - Current collector and manufacturing method thereof - Google Patents

Description

The present invention relates to a current collector including a conductive polymer film having a small volume resistivity, high mechanical strength such as tear strength, and excellent adhesion to metal foil and organic solvent resistance , and a method for producing the current collector. .

  In recent years, lithium-ion batteries have attracted attention as power sources for various electronic products including power sources for electric vehicles. Metal foils such as aluminum foil and copper foil are used as current collectors for lithium ion batteries. A binder layer containing activated carbon, a conductive agent, a binder, and the like is formed on the surface of the current collector. When charging / discharging of the lithium ion battery is repeated, peeling of the current collector and the binder layer occurs due to thermal expansion and contraction of the conductive agent, and the performance of the lithium ion battery is deteriorated. Therefore, attempts have been made to prevent the current collector and the binder layer from being peeled off by coating the surface of the current collector with a resin. A bipolar battery using an aluminum foil coated with an electron conductive polypropylene layer containing carbon black on the negative electrode side as a current collector has been studied (for example, see Patent Document 1). Although polypropylene is dissolved in a special organic solvent such as hexachlorobenzene at a high temperature, it is difficult to dry the polypropylene solution because it does not dissolve in a hydrocarbon solvent having a boiling point of 200 ° C. or less. Furthermore, the adhesion between the polypropylene layer and the current collector in the organic solvent electrolyte for a lithium ion battery is low, and the polypropylene layer and the current collector easily peel off due to vibration during the assembly of the lithium ion battery.

  On the other hand, a current collector in which a metal current collector main body is coated with a coating film composed of an acid-modified polyolefin and a conductive filler has been studied (for example, see Patent Document 2). The acid-modified polyolefin swells in an organic solvent electrolyte for a lithium ion battery, and the coating film and the metal current collector are easily peeled off.

JP 2006-302616 A JP-A-11-297332

In recent years, conductive polymer films with small volume resistivity, high mechanical strength such as tear strength, and excellent adhesion to metal foil and organic solvent resistance have been coated on the surface of the current collector of lithium ion batteries. Although demanded for use, no such conductive polymer film has been found so far.
Therefore, the problems to be solved by the present invention are a conductive polymer film and a metal having a small volume resistivity value, a high mechanical strength such as tear strength, and excellent adhesion to metal foil and organic solvent resistance. The present invention provides a current collector formed by laminating a foil and a method for producing the current collector .

The inventors of the present invention have made extensive studies in order to solve the above-mentioned problems. As a result, (1) (a) an olefin polymer, and (b) hydrogen of an aromatic vinyl-conjugated diene block copolymer as necessary. A laminate formed by laminating a conductive polymer film containing an additive, (c) a cyclic olefin resin and (d) an acid-modified polyolefin, and (2) a conductive filler, and a metal foil. It has been found that an electric body solves the above problems, and has completed the present invention.

The present invention includes (1) (a) 100 to 55% by mass of an olefin polymer, (b) 0 to 45% by mass of a hydrogenated aromatic vinyl-conjugated diene block copolymer, and (c) a cyclic olefin resin 0. Conductive polymer film and metal comprising -30 mass% and (d) 100 mass parts of polymer component containing 0-20 mass% of acid-modified polyolefin, and (2) 25-60 mass parts of conductive filler. A current collector formed by laminating a foil is provided. The preferred (a) olefin polymer is an ethylene-octene copolymer. The preferable (2) conductive filler is carbon black.

  The present invention includes (1) (a) 100 to 55% by mass of an olefin polymer, (b) 0 to 45% by mass of a hydrogenated aromatic vinyl-conjugated diene block copolymer, and (c) a cyclic olefin resin 0. A conductive polymer composition containing 100 parts by mass of a polymer component containing -30% by mass and (d) 0-20% by mass of an acid-modified polyolefin, and (2) 20-60 parts by mass of a conductive filler. Provided is a method for producing a current collector, wherein a solution obtained by dissolving or dispersing in a solvent is applied onto a metal foil and then dried.

  Furthermore, the present invention provides (1) (a) 100 to 55% by mass of an olefin polymer, (b) 0 to 45% by mass of a hydrogenated aromatic vinyl-conjugated diene block copolymer, and (c) a cyclic olefin. Conductive polymer film and metal foil containing 100 parts by mass of polymer component consisting of 0 to 30% by mass of resin and 0 to 20% by mass of (d) acid-modified polyolefin, and (2) 25 to 60 parts by mass of conductive filler A method for producing a current collector is provided, in which a step of laminating and calendering is performed.

The conductive polymer film included in the current collector of the present invention has a small volume resistivity, high mechanical strength such as tear strength, and excellent adhesion to metal foil and organic solvent resistance.

Front view of current collector AA sectional view of FIG. Diagram showing calendar forming of current collector

The conductive polymer film provided in the current collector of the present invention contains (a) an olefin polymer. The (a) olefin polymer is not limited to a specific olefin polymer. Specific examples of the (a) olefin polymer include ethylene homopolymer, propylene homopolymer, copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms, propylene and α having 4 to 20 carbon atoms. -Olefin copolymers and the like. A preferred (a) olefin polymer is a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms, and a particularly preferred (a) olefin polymer is an ethylene-octene copolymer. The ethylene-octene copolymer is a chain olefin copolymer containing an ethylene unit and a 1-octene unit, and is commercially available. Specific examples of commercially available ethylene-octene copolymers include Dow Chemical Engage (registered trademark) 8003, 8100/8107, 8137, 8150/8157, 8180, 8200/8207, 8400/8407, 8842, prime polymer Moretech (registered trademark) 0218CN, 0218CM, 0258CN, 0438CN, etc.
The content rate of the said olefin polymer in the said polymer component is 100-55 mass%.

The conductive polymer film provided in the current collector of the present invention contains a hydrogenated product of (b) an aromatic vinyl-conjugated diene block copolymer, if necessary.
Specific examples of the aromatic vinyl compound constituting the aromatic vinyl-conjugated diene block copolymer are styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, t-butylstyrene, divinyl. Examples thereof include benzene, N, N-dimethyl-p-aminoethylstyrene, 2,4-dimethylstyrene, N, N-diethyl-p-aminoethylstyrene, 2,4-dimethylstyrene, vinylnaphthalene, vinylanthracene and the like. Of these, styrene and α-methylstyrene are particularly preferred aromatic vinyl compounds. One or more aromatic vinyl compounds are used.

  Specific examples of the conjugated diene compound constituting the aromatic vinyl-conjugated diene block copolymer include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, and 2-methyl. -1,3-pentadiene, 1,3-hexadiene, 4,5-dimethyl-1,3-octadiene, and the like. Of these, 1,3-butadiene and isoprene are particularly preferred conjugated diene compounds. One or more conjugated diene compounds are used.

  (B) The content of the aromatic vinyl compound unit in the hydrogenated product of the aromatic vinyl-conjugated diene block copolymer is usually 5 to 80% by mass, preferably 10 to 70% by mass, and more preferably 20%. -60 mass%.

  Specific examples of the aromatic vinyl-conjugated diene copolymer include an aromatic vinyl compound polymer block (P) and a conjugated diene polymer block (Q), and the block structure is (PQ) nP or (P -Q) A block copolymer represented by m (where n is an integer of 1 or more, preferably an integer of 1 to 10, and m is an integer of 1 or more, preferably an integer of 2 to 10). (B) Specific examples of hydrogenated aromatic vinyl-conjugated diene block copolymers include styrene-ethylene-butene-styrene block copolymers (SEBS); styrene-ethylene-propylene-styrene block copolymers (SEPS). (S: styrene, E: ethylene, B: butene, P: propylene), respectively. Of these, styrene-ethylene-butene-styrene block copolymer (SEBS) is particularly preferable.

(B) The weight average molecular weight of the hydrogenated aromatic vinyl-conjugated diene block copolymer is preferably in the range of 5,000 to 1,000,000, more preferably 10,000 to 500,000.
(B) The hydrogenated aromatic vinyl-conjugated diene copolymer is preferably 80 to 99.9 mol%, more preferably 90 to 99.9 mol% of the unsaturated double bond in the polymer chain. More preferably, 95 to 99.9 mol% is hydrogenated. (B) Hydrogenated aromatic vinyl-conjugated diene block copolymers are commercially available. Specific examples thereof include Kraton (registered trademark) such as Kraton (registered trademark) G1650M and Kraton (registered trademark) G1657M manufactured by Kraton Japan. ) G series; Tuftec (registered trademark) H1031, Tuftec (registered trademark) H1051, etc. manufactured by Asahi Kasei Chemicals Co., Ltd .; Septon (registered trademark) 2002, Septon (registered trademark) 2004, etc. manufactured by Kuraray Co., Ltd. Septon (registered trademark) series;

The content of the hydrogenated product of the (b) aromatic vinyl-conjugated diene block copolymer in the polymer component is 0 to 45% by mass. (B) If the content of the hydrogenated aromatic vinyl-conjugated diene block copolymer is too high, pinholes are generated in the conductive polymer film.
By including the hydrogenated product of the above (b) aromatic vinyl-conjugated diene block copolymer, the tensile strength and tensile elongation of the film can be improved.

The electroconductive polymer film with which the collector of this invention is provided contains (c) cyclic olefin resin as needed. (C) The cyclic olefin resin is an amorphous resin having an aliphatic hydrocarbon ring structure in the main chain or side chain of the polymer, and specific examples thereof include JP-A 63-264646 and JP-A No. 63-264646. A ring-opening polymer of a monomer having a norbornene ring and a hydrogenated product thereof disclosed in JP-A 64-1705, JP-A-1-168724, JP-A-1-168725, etc., JP-A-60-168708 Addition polymers of monomers having a norbornene ring and α-olefins disclosed in Japanese Laid-Open Patent Publications, etc., cyclic olefins and cyclic dienes disclosed in Japanese Patent Laid-Open Nos. 6-136057 and 7-258362, etc. Examples thereof include a polymer and a hydrogenated product thereof. These (c) cyclic olefin resins are commercially available, and specific examples of commercially available products are ZEONEX (registered trademark), ZEONOR (registered trademark) manufactured by Nippon Zeon Co., Ltd., APEL (registered trademark) manufactured by Mitsui Chemicals, Inc. , APO (registered trademark), and TOPAS (registered trademark) manufactured by Polyplastics Co., Ltd. Among these, a ring-opening polymer of a monomer having a norbornene ring and a hydrogenated product thereof are preferable from the viewpoint of film forming property, chemical resistance, etc., and a hydrogenated product of a ring-opening polymer of a monomer having a norbornene ring is particularly preferable. preferable.

The monomer having a norbornene ring includes a bicyclic olefin norbornene which is an adduct of ethylene and cyclopentadiene, and a tetracyclic olefin tetracyclododecene and cyclopentadiene which are added by cyclopentadiene and a tricyclic ring. Tricyclodecadiene (also called dicyclopentadiene) which is a diene of formula, tricyclodecene which is a tricyclic olefin in which a part of its unsaturated bond is saturated by hydrogenation, and a pentamer of cyclopentadiene. Pentacyclopentadecadiene, which is a diene, pentacyclopentadecene (also called 2,3-dihydrodicyclopentadiene), which is a pentacyclic olefin in which a part of its unsaturated bond is saturated by hydrogenation; and substitution thereof Examples include bodies. Examples of the substituent include a derivative substituted with a group having no polar group such as an alkyl group, an alkylidene group or an aromatic group, a hydrogenated derivative, or a derivative obtained by dehydrogenation thereof (for example, 2-norbornene, 5 -Methyl-2-norbornene, 5,5-dimethyl-2-norbornene, 5-ethyl-2-norbornene, 5-butyl-2-norbornene, 5-ethylidene-2-norbornene, 5-hexyl-2-norbornene, 5 -Norbornene derivatives such as phenyl-2-norbornene, 5-octyl-2-norbornene, 5-octadecyl-2-norbornene, 5-ethylidene-2-norbornene, 1,4: 5,8-dimethano-1,2,3 4,4a, 5,8,8a-2,3-cyclopentadienooctahydronaphthalene, 6-methyl-1 4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 1,4: 5,10: 6,9-trimethano-1,2,3,4 4a, 5,5a, 6,9,9a, 10,10a-tetracyclododecene derivatives such as dodecahydro-2,3-cyclopentadienoanthracene); halogen, hydroxyl group, ester group, alkoxy group, cyano group, Substitutes substituted with polar groups such as amide group, imide group, silyl group (for example, 5-methoxy-carbonyl-2-norbornene, 5-cyano-2-norbornene, 5-methyl-5-methoxycarbonyl-2- Norbornene, etc.);
Specific examples of the α-olefin that is addition-copolymerized with a monomer having a norbornene ring include olefins in a narrow sense such as ethylene, propylene, 1-butene, 4-methylpentene-1, and a part of these α-olefins such as halogen. Examples include olefinic monomers substituted with polar groups.

  Cyclic olefins include cyclobutene, 1-methylcyclopentene, 3-methylcyclobutene, 3,4-diisopropenylcyclobutene, cyclopentene, 3-methylcyclopentene, cyclohexene, cyclooctene, 1-methylcyclooctene, 5-methylcyclo Examples include monocyclic cycloolefins such as octene, cyclooctatetraene, and cyclododecene, and monomers having one unsaturated bond among the above-described monomers having a norbornene ring.

  Examples of the cyclic diene include monocyclic dienes such as cyclopentadiene, 1,3-cyclohexadiene, and 1,4-cyclohexadiene, and those having two unsaturated bonds among the monomers having the norbornene ring.

  Among these monomers, a monomer having no polar group is preferably 50% by mass or more, more preferably 70% by mass or more, and particularly preferably 90% by mass or more in all monomers, and the resulting conductivity is obtained. The polymer film has excellent resistance to chemicals such as ethylene carbonate.

  Furthermore, in any of the above ring-opening polymerization and addition polymerization, various types of copolymerizable monomers may be mixed and copolymerized in each polymerization system. Examples of the copolymerizable monomer include linear or branched dienes such as butadiene and isoprene, in addition to the monomer having a norbornene ring, an α-olefin, a cyclic olefin, and a cyclic diene. The polymerization may be random, block type, or alternating type, and either 1,2-addition or 1,4-addition may be the main in addition polymerization. The ratio may be approximately the same.

  In the case where an unsaturated bond remains in the polymer after polymerization, that is, in the case of a ring-opening polymer of a monomer having a norbornene ring or an addition polymer of a cyclic diene, the conductive polymer obtained by the residual unsaturated bond Since the chemical resistance of the film is lowered, for the purpose of improving this, it is preferable to saturate 80% or more, preferably 90% or more of the unsaturated bonds by hydrogenation. Any known hydrogenation method and catalyst may be used.

  The molecular weight of the polymer is, for example, a number average molecular weight (Mn) in terms of polyisoprene measured by gel permeation chromatography using cyclohexane as a solvent, preferably 3,000 to 500,000, more preferably 8,000. The weight average molecular weight (Mw) is preferably 8,000 to 1,000,000.

  It is preferable to remove or reduce residues such as catalyst from the polymer solution after polymerization or after hydrogenation by a known method. The solvent is removed by filtration and then dried by heating or vacuum heating, or the resin solution from which metal contaminants have been removed by precipitation aggregation is directly heated or vacuum heated to remove the solvent. May be. When the solvent is a solvent suitable for producing the conductive polymer film of the present invention, it can be used without removing the solvent or by removing a part thereof. Further, the solvent can be substituted with a solvent for film production without drying.

  (C) The glass transition temperature of the cyclic olefin resin (hereinafter sometimes referred to as Tg) varies depending on the type of monomer, the proportion of the comonomer when copolymerized, the molecular weight, the hydrogenation rate, etc., but the conductive polymer film. When used as a resin for use, it is preferably −150 to + 300 ° C., more preferably −120 to + 200 ° C., and particularly preferably −100 to + 120 ° C. When it exists in this range, the softness | flexibility of an electroconductive polymer film obtained, intensity | strength, and heat resistance are highly balanced and preferable. In the present invention, Tg is a value measured by a differential scanning calorimeter (DSC).

The content rate of the said (c) cyclic olefin resin in the said polymer component is 0-30 mass%. When the content ratio of the (c) cyclic olefin resin is too high, defects such as pinholes and cracks are likely to occur in the film. By containing the (c) cyclic olefin resin, the tensile strength of the film can be improved.
The total content of the hydrogenated product of the (b) aromatic vinyl-conjugated diene block copolymer and the (c) cyclic olefin resin in the polymer component is preferably 15 to 45% by mass.

The conductive polymer film provided in the current collector of the present invention contains (d) acid-modified polyolefin as necessary. The (d) acid-modified polyolefin is a polyolefin having a carboxyl group in the molecule and is commercially available. Specific examples of the commercial product of the (d) acid-modified polyolefin include Mitsui Chemicals Co., Ltd. Unistall, Chuo Rika Kogyo Co., Ltd. Aquatex, Sumitomo Seika Co., Ltd. Sepoul John, Zyxen, CSM Latex, etc. .
The content rate in the polymer component of the (d) acid-modified polyolefin is 0 to 20% by mass, and the preferable content rate is 2 to 10% by mass. When the content ratio of the (d) acid-modified polyolefin is too high, pinholes are likely to occur in the film. By containing the (d) acid-modified polyolefin, the tensile strength and tear strength of the film can be improved.

In the conductive polymer film provided in the current collector of the present invention, in addition to the components (a), (b), (c) and (d) described above, the effects of the present invention are not impaired. , (E) Other polymers can be contained.
(E) Other polymers include conjugated diene homopolymers such as polybutadiene; conjugated diene copolymers such as styrene-butadiene random copolymers and acrylonitrile-butadiene random copolymers; acrylic rubbers; acrylic resins; Polyether rubber such as epichlorohydrin rubber and polyethylene oxide rubber; Polyether resin such as polyphenylene ether; Silicone rubber; Silicone resin; Fluoro rubber; Fluoro resin; Polyamide; Polyester;
(E) The blending amount of the other polymer is preferably 10% by mass or less, more preferably 5% by mass or less, further preferably 2% by mass or less, and particularly preferably 1% by mass or less, based on the entire polymer component. .

The conductive polymer film provided in the current collector of the present invention contains a conductive filler. Specific examples of the conductive filler include carbon black, graphite, powder or fibrous metal or metal oxide.

Specific examples of the carbon black include furnace blacks such as conductive furnace black, super conductive furnace black, and extra conductive furnace black; conductive channel black; acetylene black; Specific examples of commercially available carbon blacks include Connexex CF (Conductive Furnace Black manufactured by Continental Carbon Co., Ltd.), Ketjen Black EC (Conductive Furnace Black manufactured by Ketchen Black International Co., Ltd.), and Vulcan C (Conductive Furnace manufactured by Cabot Corp.). Furnace Black), BLACK PEARLS 2000 (Conductive Furnace Black, manufactured by Cabot Corporation), Denka Black (acetylene black, manufactured by Denki Kagaku Kogyo Co., Ltd.), and the like. DBP oil absorption of carbon black is 300 cm ^3/100 g or more, and a BET surface area is 500 meters ² / g or more.

Specific examples of graphite include scale-like natural graphite, artificial graphite, graphite fiber, and the like.
Specific examples of the metal are iron, copper, nickel, aluminum, titanium, tantalum, niobium, vanadium and any alloy containing two or more thereof.
Specific examples of the metal oxide can include the oxides exemplified as the metal. Specific examples include iron oxide, copper oxide, nickel oxide, aluminum oxide, titanium oxide, tantalum oxide, niobium oxide, vanadium oxide, and oxides of any alloy containing two or more of the above metals.

  The said conductive filler can be used individually or in combination of at least 2 types. Content of an electroconductive filler is 25-60 mass parts with respect to 100 mass parts of said polymer components. When there is too little content of an electroconductive filler, the resistance value of a film is too high and the electroconductivity of a film becomes low. On the other hand, when there is too much content of a conductive filler, a conductive polymer composition cannot be made into a film.

The conductive polymer film provided in the current collector of the present invention may contain various compounding agents that are usually used in the resin industry field.
The conductive polymer film provided in the current collector of the present invention may contain a stabilizer. Specific examples of the stabilizer include phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants and the like. Among these, phenolic antioxidants are preferable, and alkyl-substituted phenolic antioxidants are particularly preferable. These stabilizers may be used alone or in combination of two or more. Although the compounding quantity of a stabilizer is suitably selected according to a use purpose, it is the range of 0.001-10 mass parts normally with respect to 100 mass parts of said polymer components.

Although the metal which comprises the metal foil with which the collector of this invention is provided is not specifically limited, The specific example of a preferable thing is aluminum, copper, and nickel. The preferred thickness of the conductive polymer film provided in the current collector of the present invention is 10 to 50 μm. The preferred thickness of the metal foil is 5 to 25 μm. Furthermore, the preferable thickness of the current collector of the present invention is 30 to 60 μm, and the particularly preferable thickness of the current collector of the present invention is 45 to 50 μm.

  The manufacturing method of the current collector of the present invention is not limited to a specific method. One embodiment of the production method includes (1) (a) 100 to 55% by mass of an olefin polymer, (b) 0 to 45% by mass of a hydrogenated aromatic vinyl-conjugated diene block copolymer, (c Conductivity) comprising 100 parts by mass of a polymer component comprising 0) 30% by mass of a cyclic olefin resin and 0-20% by mass of an acid-modified polyolefin, and (2) 20-60 parts by mass of a conductive filler. In this method, a solution obtained by dissolving or dispersing the polymer composition in a solvent is applied onto a substrate or a metal foil and then dried.

  The solvent is a solvent that dissolves the olefin polymer, a hydrogenated aromatic vinyl-conjugated diene block copolymer, a cyclic olefin resin, and an acid-modified polyolefin at room temperature or under heating, It is not limited to a specific solvent. Specific examples of the solvent include aromatic hydrocarbon compounds such as benzene, toluene and xylene; saturation of n-hexane, cyclohexane, methylcyclohexane, ethylcyclohexane, nonane, decane, decalin, tetralin, dodecane, gasoline, industrial gasoline, etc. Aliphatic and alicyclic hydrocarbon compounds;

  If necessary, a compounding agent such as a softening agent such as paraffinic process oil or naphthenic process oil or an antiaging agent may be added to the conductive polymer composition as long as the effects of the present invention are not impaired.

  The method for producing the conductive polymer composition may be a method of kneading an olefin polymer, a conductive filler, and an optional component added as necessary, and a method of dissolving or dispersing each component in a solvent. It can be.

  If the concentration of the component added to the solvent is too low, a conductive polymer film having a sufficient thickness cannot be obtained. Conversely, if the concentration is too high, the viscosity of the conductive polymer composition becomes too high, and the conductivity The thickness of the polymer film is not uniform.

The method for producing the conductive polymer film of the present invention will be described in more detail. First, the lump and the undispersed material in the conductive polymer composition are removed by a filter or the like as necessary. Specific examples of the filter to be used include a fiber-like fiber, a metal or the like woven in a mesh shape, or a fine fine hole drilled into a planar material.
Further, defoaming is performed as necessary to remove bubbles contained in the solution. Specific examples of the defoaming method include a vacuum method and an ultrasonic method.

  The prepared solution (including the dispersion) is placed on a releasable substrate or metal foil that is a smooth flat surface such as polyethylene terephthalate, polytetrafluoroethylene, paper, glass plate, polyester film, and polyvinyl chloride film. Using a coater, doctor knife, Meir bar, roll coat, die coat, etc., or by spraying, brushing, rolling, spin coating, dipping, etc., cast and coat so that the thickness is uniform. When a desired film thickness cannot be obtained by a single coating, the coating can be repeated.

  Thereafter, the film is usually dried at about 30 to 150 ° C. for about 5 to 180 minutes to remove the solvent, thereby forming a film or a current collector. The film is usually peeled off from the substrate, but it is not necessary. Also, the film can be dried or annealed again after peeling.

  The residual solvent concentration is 5% by mass or less, preferably 2% by mass or less, more preferably 1% by mass or less, and still more preferably 0.5% by mass or less by drying and removing the solvent. If the drying temperature is equal to or higher than the boiling point of the solvent or near the boiling point, foaming may occur and unevenness may occur on the surface. Therefore, the drying temperature is determined according to the characteristics of the solvent. The drying temperature is determined with reference to a temperature 5 ° C. or more, preferably 10 ° C. or more lower than the boiling point of the solvent, and the coating solution is usually dried in the range of 30 to 150 ° C. in consideration of the boiling point.

  Another embodiment of the method for producing a current collector of the present invention is as follows: (1) (a) 100 to 55% by mass of an olefin polymer, (b) hydrogenated product of aromatic vinyl-conjugated diene block copolymer 0 ~ 45% by mass, (c) 100 parts by mass of a polymer component containing 0-30% by mass of a cyclic olefin resin and (d) 0-20% by mass of an acid-modified polyolefin, and (2) 20-60 conductive fillers. In this method, a conductive polymer film containing a mass part and a metal foil are laminated and calendered. The said conductive polymer film is formed on a base material similarly to the manufacturing method of the above-mentioned film. The conductive polymer film and metal foil formed on the substrate are laminated, and the obtained laminate is calendered by a pressing means such as a pair of rolls, and the conductive polymer film and metal foil are laminated. Glue. After the calendar treatment, the substrate is usually peeled off from the conductive polymer film, but it is not necessary.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the following examples, “part” and “%” are based on mass unless otherwise specified. The measuring methods of (1) volume resistivity, (2) tensile strength, and (3) tear strength of the conductive polymer film are as follows.
(1) Volume resistivity value The surface resistance value (Ω) of a 5 cm × 5 cm test piece was measured at 23 ° C. using a resistance meter (Miliohm Hitester 3540, manufactured by Hioki Electric Co., Ltd.).

(2) Tensile strength Tensile strength was measured in accordance with JIS K 7127 under the conditions of specimen type 2, width 20 mm, 200 mm / min, and 23 ° C.
(3) Tear Strength Tear strength was measured at 23 ° C. by the trouser tear method according to JIS K 7128-1.

Example 1
The components shown in Table 1 were added to cyclohexane in an amount five times the total mass of ethylene-octene copolymer, hydrogenated aromatic vinyl-conjugated diene block copolymer and carbon black, and the dispersion was added. Further, a steel ball having a diameter of 5 mm is added to the obtained dispersion for the same mass as the blending component, and the dispersion into which the steel ball has been added is used as a paint shaker (disperser for testing manufactured by Toyo Seiki Seisakusho Co., Ltd.). For 120 minutes to produce a uniform paint. The obtained paint was cast on a polyethylene terephthalate film having a thickness of 50 μm using a doctor blade having a gap of 400 μm. The polyethylene terephthalate film to which the paint was applied was allowed to stand on a hot plate at 80 ° C. for 30 minutes and then dried at 100 ° C. for 1 hour to obtain a conductive polymer film. A predetermined test piece was cut out from the film, and its volume resistivity, tensile strength, and tear strength were measured.

On the other hand, the paint was cast on a 17 μm thick aluminum foil b on which a 20 μm thick polyethylene terephthalate film a was partially placed using a doctor blade with a 400 μm gap. The aluminum foil b to which the paint is applied is left on a hot plate at 80 ° C. for 30 minutes and then dried at 100 ° C. for 1 hour to produce a current collector in which the aluminum foil b and the conductive polymer film c are laminated. (FIGS. 1 and 2). A strip-shaped test piece is cut out from the current collector (broken line in FIG. 2), the polyethylene terephthalate film a and the aluminum foil b are peeled off in air or methyl ethyl ketone, and the aluminum foil b and the conductive polymer film c are bonded. Sex was evaluated according to the following criteria.
A: Adhesiveness between the aluminum foil b and the conductive polymer film c is high, and the conductive polymer film c is cut.
B: Adhesiveness between the aluminum foil b and the conductive polymer film c is low, and the aluminum foil b and the conductive polymer film c are peeled off.

Further, the strip-shaped test piece was immersed in diethyl carbonate for 24 hours and then taken out, the droplets on the surface were removed, the weight of the test piece was measured, and the organic solvent resistance of the conductive polymer film c was determined according to the following criteria. Evaluated according to.
A: The weight increase rate of the test piece was less than 5%.
B: The rate of weight increase of the test piece was 5% or more.
The results of each test are shown in Table 1.

Examples 2 to 5 and 7, Comparative Examples 1 to 3
The same operation as in Example 1 was performed except that the blending ratio of the blending components was changed as shown in Table 1. The results are shown in Table 1.

Example 6
The blending ratio of the blending components was changed as shown in Table 1, and the volume resistivity, tensile strength and tear strength of the conductive polymer film were measured in the same manner as in Example 1. On the other hand, the polyethylene terephthalate film a ′ coated with the paint is left on a hot plate at 80 ° C. for 30 minutes, and then dried at 100 ° C. for 1 hour to laminate the polyethylene terephthalate film a ′ and the conductive polymer film b ′. A laminate that has been made was created. Thereafter, an aluminum foil c ′ having a thickness of 17 μm is overlapped with the conductive polymer film b ′ of the laminate, and calendered under conditions of a linear pressure of 3 t / cm, a roll temperature of 100 ° C., and a linear velocity of 1 m / min. A current collector in which b ′ and a conductive polymer film c ′ were laminated was produced (FIG. 3). A strip-shaped test piece was cut out from the current collector, and the adhesion between the aluminum foil b ′ and the conductive polymer film c ′ and the organic solvent resistance of the conductive polymer film c ′ were measured in the same manner as in Example 1. did. The results of each test are shown in Table 1.

1) Dow Chemical Engage (registered trademark) 8137
2) Clayton (registered trademark) G1657M (styrene content: 13% by mass) manufactured by Clayton Japan
3) ZEONOR (registered trademark) 1060R manufactured by Nippon Zeon Co., Ltd.
4) Unistor (registered trademark) H-100T manufactured by Mitsui Chemicals, Inc.
5) Ketchen Black International Co., Ltd. Ketchen black (registered trademark) EC-600JD (DBP oil absorption of 495cm ³ / 100g, BET surface area of 1270m ² / g)

The volume specific resistance values of the films of Examples 1 to 7 which are the conductive polymer films of the present invention were small, the tensile strength and the tear strength were high, and the adhesion to the aluminum foil and the organic solvent resistance were excellent. .
The conductive polymer film of Comparative Example 1 in which the content of the olefin polymer was too small had a large number of pinholes, and the physical properties of the film were not measured because the film was not practical.
The adhesiveness with the aluminum foil in the methyl ethyl ketone of the conductive polymer film of the comparative example 2 which does not contain an olefin type polymer but uses only acid-modified polyolefin as a resin component was low.
Adhesiveness with aluminum foil in methyl ethyl ketone of the conductive polymer film of Comparative Example 3 containing no hydrogenated product of aromatic vinyl-conjugated diene block copolymer as a resin component and containing no olefin polymer and The organic solvent resistance was low.

The conductive polymer film provided in the current collector of the present invention has a small volume resistivity value. Therefore, an example of a typical use of the current collector of the present invention is a current collector for a lithium ion battery using an organic electrolyte. In addition to the basic cell, which is the smallest structural unit, a lithium ion battery in which a plurality of basic cells are connected in series to increase the output voltage, a lithium ion battery that is connected in parallel to increase the output current, and a combination of these power sources May also be included in the lithium ion battery.
Current collector of the present invention is produced by laminating the conductive polymer film and the metal foil common method of solution casting or calender molding. The adhesion of the conductive polymer film and metal foil current collector comprises of the present invention is high, since the organic solvent resistance is high conductive polymer film current collector comprises the present invention, the present invention condensing The life of a lithium ion battery using an electric body and an organic electrolyte is long.

Claims (5)

(1) (a) 100-55 mass% of olefin polymer, (b) 0-45 mass% of hydrogenated aromatic vinyl-conjugated diene block copolymer, (c) 0-30 mass% of cyclic olefin resin And (d) 100 parts by mass of a polymer component containing 0 to 20% by mass of an acid-modified polyolefin and (2) 25 to 60 parts by mass of a conductive filler and a metal foil are laminated. Current collector . The current collector according to claim 1, wherein the (a) olefin polymer is an ethylene-octene copolymer. The current collector according to claim 1 or 2, wherein the conductive filler (2) is carbon black.   (1) (a) 100-55 mass% of olefin polymer, (b) 0-45 mass% of hydrogenated aromatic vinyl-conjugated diene block copolymer, (c) 0-30 mass% of cyclic olefin resin And (d) a conductive polymer composition containing 100 parts by mass of a polymer component containing 0 to 20% by mass of an acid-modified polyolefin and (2) 20 to 60 parts by mass of a conductive filler is dissolved or dissolved in a solvent. A method for producing a current collector, wherein a step of applying a dispersed solution onto a metal foil and then drying is performed.   (1) (a) 100-55 mass% of olefin polymer, (b) 0-45 mass% of hydrogenated aromatic vinyl-conjugated diene block copolymer, (c) 0-30 mass% of cyclic olefin resin And (d) 100 parts by mass of a polymer component containing 0 to 20% by mass of an acid-modified polyolefin, and (2) a conductive polymer film containing 20 to 60 parts by mass of a conductive filler and a metal foil are laminated. A method for manufacturing a current collector, wherein the step of calendar molding is performed.

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