WO2015041184A1 - Method for manufacturing coated active material for use in lithium-ion battery - Google Patents

Abstract

The purpose of this invention is to provide a method for manufacturing a coated active material for use in a lithium-ion battery, said method being capable of improving the electron conductivity of said active material. This method for manufacturing a coated active material for use in a lithium-ion battery, said coated active material comprising a lithium-ion-battery active material with at least part of the surface thereof coated by a coating agent containing a conductivity-improving agent and a coating resin, is characterized in that in the presence of said lithium-ion-battery active material, a resin solution containing the coating resin is inputted and the conductivity-improving agent is added after that.

Description

Method for producing coated active material for lithium ion battery

The present invention relates to a method for producing a coated active material for a lithium ion battery.

In recent years, reduction of carbon dioxide emissions has been strongly desired for environmental protection. In the automobile industry, there are high expectations for reducing carbon dioxide emissions by introducing electric vehicles (EVs) and hybrid electric vehicles (HEVs), and we are eager to develop secondary batteries for motor drives that hold the key to their practical application. Has been done. As a secondary battery, attention is focused on a lithium ion secondary battery that can achieve a high energy density and a high output density.

In general, a lithium ion secondary battery is formed by applying a positive electrode or a negative electrode active material or the like to a positive electrode or negative electrode current collector using a binder. In the case of a bipolar battery, a positive electrode active material or the like is applied to one surface of the current collector using a binder and a positive electrode layer is applied to the opposite surface, and a negative electrode active material or the like is applied to the opposite surface using a binder. Thus, a bipolar electrode having a negative electrode layer is formed.

Electrode active materials vary in electron conductivity depending on the type, but at present, a conductive additive for enhancing electron conductivity is indispensable for any active material. As conductive aids, carbonaceous conductive materials such as graphite and carbon black are used, but since these are particulate, it is necessary to add them at a high concentration in order to obtain the desired electronic conductivity. .

On the other hand, there is a technique of using a conductive polymer to obtain a desired electronic conductivity. For example, Patent Document 1 discloses a specific conductive polymer organic solvent dispersion and a carbonaceous conductive material. A conductive additive composition prepared by mixing is disclosed.

JP 2011-100594 A

However, in recent years, since there is a further demand for higher capacity of batteries, it is necessary to further improve the conductivity of the electrodes.
The present inventors have found that there is a possibility that the conductivity of the electrode can be increased by coating a part of the surface of the lithium ion battery active material with a coating agent containing a coating resin and a conductive additive. However, various methods are conceivable as specific methods for coating the surface of the lithium ion battery active material, and there is room for study.
This invention is made | formed in view of the said condition, and it aims at providing the manufacturing method of the covering active material for lithium ion batteries which can improve the electronic conductivity of an active material.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have reached the present invention.
That is, in the method for producing a coated active material for a lithium ion battery according to the present invention, a coating for a lithium ion battery in which at least a part of the surface of the lithium ion battery active material is coated with a coating material containing a coating resin and a conductive additive. A method for producing an active material, wherein a resin solution containing the coating resin is added in the presence of the lithium ion battery active material, and then the conductive auxiliary agent is added.

According to the method for producing a coated active material for a lithium ion battery according to the present invention, a coating resin adheres to the periphery of the active material, and further a conductive assistant adheres to the coated active material in which the conductive assistant adheres to the active material. Is obtained. And the coating active material for lithium ion batteries obtained with the manufacturing method of this invention is excellent in electronic conductivity.

Hereinafter, the present invention will be described in detail.
The method for producing a coated active material for a lithium ion battery according to the present invention includes a coated active material for a lithium ion battery in which at least a part of the surface of the lithium ion battery active material is coated with a coating material containing a coating resin and a conductive additive. A manufacturing method of
In the presence of the lithium ion battery active material, a resin solution containing the coating resin is added, and then the conductive assistant is added.

In the method for producing a coating active material for a lithium ion battery according to the present invention, a resin solution containing a coating resin is added in the presence of the lithium ion battery active material, and then a conductive additive is added. Hereinafter, these steps will be described.

(1) First, a resin solution containing a coating resin is introduced in the presence of a lithium ion battery active material.
Thereby, the resin solution can be attached around the lithium ion battery active material.

Examples of the lithium ion battery active material (Y) include a positive electrode active material (Y1) and a negative electrode active material (Y2).
As the positive electrode active material (Y1), a composite oxide of lithium and a transition metal (for example, LiCoO ₂ , LiNiO ₂ , LiMnO ₂ and LiMn ₂ O ₄ ), a transition metal oxide (for example, MnO ₂ and V ₂ O ₅ ), Transition metal sulfides (eg, MoS ₂ and TiS ₂ ) and conductive polymers (eg, polyaniline, polyvinylidene fluoride, polypyrrole, polythiophene, polyacetylene, poly-p-phenylene, and polycarbazole).
Examples of the negative electrode active material (Y2) include graphite, amorphous carbon, polymer compound fired bodies (for example, those obtained by firing and carbonizing phenol resin, furan resin, etc.), cokes (for example, pitch coke, needle coke, petroleum coke, etc.) ), Carbon fibers, conductive polymers (eg, polyacetylene and polypyrrole), tin, silicon, and metal alloys (eg, lithium-tin alloy, lithium-silicon alloy, lithium-aluminum alloy, and lithium-aluminum-manganese alloy), Examples include composite oxides of lithium and transition metals (for example, Li ₄ Ti ₅ O ₁₂ ).

It is preferable that the lithium ion battery active material itself has a low conductivity because the effect of improving the conductivity can be greatly obtained. Therefore, as the positive electrode active material (Y1), a composite oxide of lithium and a transition metal (for example, LiCoO ₂ , LiNiO ₂ , LiMnO ₂ and LiMn ₂ O ₄ ), a transition metal oxide (for example, MnO ₂ and V ₂ O ₅ ) Transition metal sulfides (eg MoS ₂ and TiS ₂ ) are preferred. As the negative electrode active material (Y2), a composite oxide of lithium and a transition metal (for example, Li ₄ Ti ₅ O ₁₂ or the like) is preferable.

The resin solution is a solution in which the coating resin is dissolved in the solvent without remaining undissolved.
The coating resin may be a thermoplastic resin or a thermosetting resin. For example, vinyl resin (A), urethane resin (B), polyester resin (C), polyamide resin (D), Other resin (E), a mixture thereof, etc. are mentioned. Of these, vinyl resin (A), urethane resin (B), polyester resin (C), polyamide resin (D), and mixtures thereof are preferred, and vinyl resin (A), urethane resin (B), polyester resin (C And polyamide resin (D) are more preferred.

The vinyl resin (A) is a resin comprising a polymer (A1) having the vinyl monomer (a) as an essential constituent monomer.
In particular, the polymer (A1) preferably contains a vinyl monomer (a1) having a carboxyl group or an acid anhydride group as the vinyl monomer (a) and a vinyl monomer (a2) represented by the following general formula (1). .
CH ₂ = C (R ¹ ) COOR ² (1)
[In Formula (1), R ¹ is a hydrogen atom or a methyl group, and R ² is a branched alkyl group having 4 to 36 carbon atoms. ]

Examples of the vinyl monomer (a1) having a carboxyl group or an acid anhydride group include monocarboxylic acids having 3 to 15 carbon atoms such as (meth) acrylic acid, crotonic acid and cinnamic acid; (anhydrous) maleic acid, fumaric acid, ( Anhydric) dicarboxylic acids having 4 to 24 carbon atoms such as itaconic acid, citraconic acid, and mesaconic acid; polycarboxylic acids having 6 to 24 carbon atoms such as aconitic acid and other polyvalent carboxylic acids having a valence of 6 or more. . Among these, (meth) acrylic acid is preferable, and methacrylic acid is more preferable.

In the vinyl monomer (a2) represented by the general formula (1), R ¹ represents a hydrogen atom or a methyl group. R ¹ is preferably a methyl group.
R ² is a branched alkyl group having 4 to 36 carbon atoms. Specific examples of R ² include a 1-alkylalkyl group [1-methylpropyl group (sec-butyl group), 1,1-dimethylethyl group (tert -Butyl group), 1-methylbutyl group, 1-ethylpropyl group, 1,1-dimethylpropyl group, 1-methylpentyl group, 1-ethylbutyl group, 1-methylhexyl group, 1-ethylpentyl group, 1-methyl Heptyl, 1-ethylhexyl, 1-methyloctyl, 1-ethylheptyl, 1-methylnonyl, 1-ethyloctyl, 1-methyldecyl, 1-ethylnonyl, 1-butyleicosyl, Hexyl octadecyl group, 1-octyl hexadecyl group, 1-decyl tetradecyl group, 1-undecyl tridecyl group, etc.], 2-alkylalkyl [2-methylpropyl group (iso-butyl group), 2-methylbutyl group, 2-ethylpropyl group, 2,2-dimethylpropyl group, 2-methylpentyl group, 2-ethylbutyl group, 2-methylhexyl group, 2 -Ethylpentyl group, 2-methylheptyl group, 2-ethylhexyl group, 2-methyloctyl group, 2-ethylheptyl group, 2-methylnonyl group, 2-ethyloctyl group, 2-methyldecyl group, 2-ethylnonyl group, 2 -Hexyl octadecyl group, 2-octyl hexadecyl group, 2-decyl tetradecyl group, 2-undecyl tridecyl group, 2-dodecyl hexadecyl group, 2-tridecyl pentadecyl group, 2-decyl octadecyl group, 2- Tetradecyloctadecyl group, 2-hexadecyloctadecyl group, 2-tetradecyleicosyl group, 2-hexyl Sadecyl eicosyl group, etc.] 3-34-alkylalkyl group (3-alkylalkyl group, 4-alkylalkyl group, 5-alkylalkyl group, 32-alkylalkyl group, 33-alkylalkyl group and 34-alkylalkyl group) Group), propylene oligomer (7 to 11 mer), ethylene / propylene (molar ratio 16/1 to 1/11) oligomer, isobutylene oligomer (7 to 8 mer), and α-olefin (5 to 5 carbon atoms). 20) A mixed alkyl group containing one or more branched alkyl groups such as a residue obtained by removing a hydroxyl group from an oxo alcohol obtained from an oligomer (4 to 8 mer) or the like.
Of these, a 2-alkylalkyl group is preferable, and a 2-ethylhexyl group and a 2-decyltetradecyl group are more preferable.

In addition to the monomer constituting the polymer (A1), in addition to the vinyl monomer (a1) having a carboxyl group or an acid anhydride group and the vinyl monomer (a2) represented by the general formula (1), The copolymerizable vinyl monomer (a3) which does not contain active hydrogen may be contained.
Examples of the copolymerizable vinyl monomer (a3) containing no active hydrogen include the following (a31) to (a38).
(A31) Hydrocarbyl (meth) acrylate formed from monool having 1 to 20 carbon atoms and (meth) acrylic acid The monool includes (i) an aliphatic monool (methanol, ethanol, n- or i (Propyl alcohol, n-butyl alcohol, n-pentyl alcohol, n-octyl alcohol, nonyl alcohol, decyl alcohol, lauryl alcohol, tridecyl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, etc.), (ii) alicyclic mono All (such as cyclohexyl alcohol), (iii) araliphatic monool (such as benzyl alcohol) and a mixture of two or more of these.

(A32) poly (n = 2 to 30) oxyalkylene (carbon number 2 to 4) alkyl (carbon number 1 to 18) ether (meth) acrylate [methanol ethylene oxide (hereinafter abbreviated as EO) 10 mol adduct (meta ) Propylene oxide of acrylate, methanol (hereinafter abbreviated as PO), 10 mol adduct (meth) acrylate, etc.]

(A33) a nitrogen-containing vinyl compound (a33-1) an amide group-containing vinyl compound (i) a (meth) acrylamide compound having 3 to 30 carbon atoms, such as N, N-dialkyl (1 to 6 carbon atoms) or diaralkyl (carbon number) 7 to 15) (meth) acrylamide (N, N-dimethylacrylamide, N, N-dibenzylacrylamide, etc.), diacetone acrylamide (ii) amide group having 4 to 20 carbon atoms, excluding the above (meth) acrylamide compounds Vinyl compounds such as N-methyl-N-vinylacetamide, cyclic amides (pyrrolidone compounds (having 6 to 13 carbon atoms, such as N-vinylpyrrolidone))

(A33-2) (meth) acrylate compound (i) dialkyl (1 to 4 carbon atoms) aminoalkyl (1 to 4 carbon atoms) (meth) acrylate [N, N-dimethylaminoethyl (meth) acrylate, N, N -Diethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate, morpholinoethyl (meth) acrylate, etc.]
(Ii) Quaternary ammonium group-containing (meth) acrylate {quaternary amino group-containing (meth) acrylate [N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, etc.]] (Quaternized with a quaternizing agent such as methyl chloride, dimethyl sulfate, benzyl chloride, dimethyl carbonate, etc.)}

(A33-3) Heterocycle-containing vinyl compound Pyridine compound (carbon number 7 to 14, such as 2- or 4-vinylpyridine), imidazole compound (carbon number 5 to 12, such as N-vinylimidazole), pyrrole compound (carbon number) 6 to 13, for example, N-vinylpyrrole), pyrrolidone compound (6 to 13 carbon atoms, for example, N-vinyl-2-pyrrolidone)

(A33-4) Nitrile group-containing vinyl compound A nitrile group-containing vinyl compound having 3 to 15 carbon atoms, such as (meth) acrylonitrile, cyanostyrene, cyanoalkyl (1 to 4 carbon atoms) acrylate

(A33-5) Other nitrogen-containing vinyl compounds Nitro group-containing vinyl compounds (carbon number 8 to 16, for example, nitrostyrene), etc.

(A34) Vinyl hydrocarbon (a34-1) Aliphatic vinyl hydrocarbon Olefin having 2 to 18 or more carbon atoms (ethylene, propylene, butene, isobutylene, pentene, heptene, diisobutylene, octene, dodecene, octadecene, etc.), Dienes having 4 to 10 or more carbon atoms (butadiene, isoprene, 1,4-pentadiene, 1,5-hexadiene, 1,7-octadiene, etc.), etc.

(A34-2) Alicyclic vinyl hydrocarbon Cyclic unsaturated compound having 4 to 18 or more carbon atoms, such as cycloalkene (for example, cyclohexene), (di) cycloalkadiene [for example, (di) cyclopentadiene], terpene ( For example, pinene and limonene), indene

(A34-3) Aromatic vinyl hydrocarbon Aromatic unsaturated compounds having 8 to 20 or more carbon atoms, such as styrene, α-methylstyrene, vinyltoluene, 2,4-dimethylstyrene, ethylstyrene, isopropylstyrene, butyl Styrene, phenyl styrene, cyclohexyl styrene, benzyl styrene

(A35) Vinyl ester Aliphatic vinyl ester [C4-15, for example, alkenyl ester of aliphatic carboxylic acid (mono- or dicarboxylic acid) (for example, vinyl acetate, vinyl propionate, vinyl butyrate, diallyl adipate, isopropenyl acetate, Vinyl methoxyacetate)]
Aromatic vinyl esters [containing 9 to 20 carbon atoms, eg alkenyl esters of aromatic carboxylic acids (mono- or dicarboxylic acids) (eg vinyl benzoate, diallyl phthalate, methyl-4-vinyl benzoate), aromatic ring containing aliphatic carboxylic acid Ester (eg acetoxystyrene)]

(A36) Vinyl ether Aliphatic vinyl ether [C3-15, such as vinylalkyl (C1-10) ether (vinyl methyl ether, vinyl butyl ether, vinyl-2-ethylhexyl ether, etc.), vinyl alkoxy (C1-6) ) Alkyl (1 to 4 carbon atoms) ether (vinyl-2-methoxyethyl ether, methoxybutadiene, 3,4-dihydro-1,2-pyran, 2-butoxy-2'-vinyloxydiethyl ether, vinyl-2- Ethyl mercaptoethyl ether, etc.), poly (2-4) (meth) allyloxyalkanes (2-6 carbon atoms) (diallyloxyethane, triaryloxyethane, tetraallyloxybutane, tetrametaallyloxyethane, etc.)]
Aromatic vinyl ether (C8-20, such as vinyl phenyl ether, phenoxystyrene)

(A37) Vinyl ketone Aliphatic vinyl ketone (having 4 to 25 carbon atoms, such as vinyl methyl ketone, vinyl ethyl ketone)
Aromatic vinyl ketone (C9-21, such as vinyl phenyl ketone)

(A38) Unsaturated dicarboxylic acid diester Unsaturated dicarboxylic acid diester having 4 to 34 carbon atoms such as dialkyl fumarate (two alkyl groups are linear, branched or alicyclic groups having 1 to 22 carbon atoms) ), Dialkyl maleate (two alkyl groups are straight, branched or alicyclic groups having 1 to 22 carbon atoms)

Of those exemplified as (a3), from the viewpoint of withstand voltage, (a31), (a32) and (a33) are preferred, and methyl (meth) acrylate and ethyl of (a31) are more preferred. (Meth) acrylate and butyl (meth) acrylate.

In the polymer (A1), a vinyl monomer (a1) having a carboxyl group or an acid anhydride group, a vinyl monomer (a2) represented by the general formula (1), and a copolymerizable vinyl monomer (a3) containing no active hydrogen ) Based on the weight of the polymer (A1), (a1) is 0.1 to 80% by weight, (a2) is 0.1 to 99.9% by weight, and (a3) is 0 to 99%. It is preferably 8% by weight.
When the content of the monomer is within the above range, the liquid absorptivity to the electrolytic solution is good.
More preferable contents are 15 to 60% by weight of (a1), 5 to 60% by weight of (a2), and 5 to 80% by weight of (a3). Further more preferable contents are 25 to 60% of (a1). 50% by weight, (a2) is 15 to 45% by weight, and (a3) is 20 to 60% by weight.

The preferable lower limit of the number average molecular weight of the polymer (A1) is 3,000, more preferably 50,000, still more preferably 100,000, particularly preferably 200,000, and the preferable upper limit is 2,000,000. It is preferably 1,500,000, more preferably 1,000,000, and particularly preferably 800,000.

The number average molecular weight of the polymer (A1) can be determined by gel permeation chromatography (hereinafter abbreviated as GPC) measurement under the following conditions.
Apparatus: Alliance GPC V2000 (manufactured by Waters)
Solvent: Orthodichlorobenzene Reference material: Polystyrene detector: RI
Sample concentration: 3 mg / ml
Column stationary phase: PLgel 10 μm, MIXED-B 2 in series (manufactured by Polymer Laboratories)
Column temperature: 135 ° C

The solubility parameter (hereinafter abbreviated as SP value) of the polymer (A1) is preferably 9.0 to 20.0 (cal / cm ³ ) ^1/2 . The SP value of the polymer (A1) is more preferably 10.0 to 18.0 (cal / cm ³ ) ^1/2 , and 11.5 to 14.0 (cal / cm ³ ) ^1/2 . More preferably. The SP value of the polymer (A1) is preferably 9.0 to 20.0 (cal / cm ³ ) ^{1/2 from} the viewpoint of liquid absorption of the electrolytic solution.
The SP value is calculated by the Fedors method. The SP value can be expressed by the following equation.
SP value (δ) = (ΔH / V) ^1/2
In the formula, ΔH represents the heat of vaporization (cal), and V represents the molar volume (cm ³ ).
ΔH and V are the sum of the heat of molar evaporation (ΔH) of the atomic group described in “POLYMER ENGINEERING AND SCIENCE, 1974, Vol. 14, No. 2, ROBERT F. FEDORS. (Pages 151 to 153)”. The total molar volume (V) can be used.
The SP value is an index indicating that those having a close numerical value are easily mixed with each other (high compatibility), and those having a close numerical value are difficult to mix.

The glass transition point of the polymer (A1) [hereinafter abbreviated as Tg, measurement method: DSC (scanning differential thermal analysis) method] is preferably 80 to 200 ° C., more preferably 90, from the viewpoint of battery heat resistance. -180 ° C, more preferably 100-150 ° C.

The polymer (A1) can be produced by a known polymerization method (bulk polymerization, solution polymerization, emulsion polymerization, suspension polymerization, etc.).
In the polymerization, known polymerization initiators {azo initiators [2,2′-azobis (2-methylpropionitrile), 2,2′-azobis (2,4-dimethylvaleronitrile, etc.)], peroxides System initiators (benzoyl peroxide, di-t-butyl peroxide, lauryl peroxide, etc.)} can be used.
The amount of the polymerization initiator used is preferably 0.01 to 5% by weight, more preferably 0.05 to 2% by weight, still more preferably 0.1 to 1.5% by weight, based on the total weight of the monomers. .

Examples of the solvent used in the solution polymerization include esters (having 2 to 8 carbon atoms such as ethyl acetate and butyl acetate), alcohols (having 1 to 8 carbon atoms such as methanol, ethanol and octanol), hydrocarbons (having carbon atoms). 4 to 8, such as n-butane, cyclohexane and toluene) and ketones (3 to 9, carbon atoms such as methyl ethyl ketone), and the amount used is usually 5 to 900%, preferably 10 to 400, based on the total weight of the monomers. %, More preferably 30 to 300% by weight, and the monomer concentration is usually 10 to 95% by weight, preferably 20 to 90% by weight, more preferably 30 to 80% by weight.

Examples of the dispersion medium in emulsion polymerization and suspension polymerization include water, alcohol (for example, ethanol), ester (for example, ethyl propionate), light naphtha and the like, and examples of the emulsifier include higher fatty acid (carbon number 10 to 24) metal salt. (For example, sodium oleate and sodium stearate), higher alcohol (10 to 24 carbon atoms) sulfate metal salt (for example, sodium lauryl sulfate), ethoxylated tetramethyldecynediol, sodium sulfoethyl methacrylate, dimethylaminomethyl methacrylate, etc. Is mentioned. Furthermore, you may add polyvinyl alcohol, polyvinylpyrrolidone, etc. as a stabilizer.
The monomer concentration of the solution or dispersion is usually 5 to 95% by weight, preferably 10 to 90% by weight, more preferably 15 to 85% by weight. The amount of the polymerization initiator used is usually based on the total weight of the monomers. 0.01 to 5% by weight, preferably 0.05 to 2% by weight.
In the polymerization, known chain transfer agents such as mercapto compounds (such as dodecyl mercaptan and n-butyl mercaptan) and / or halogenated hydrocarbons (such as carbon tetrachloride, carbon tetrabromide and benzyl chloride) can be used. . The amount used is usually 2% by weight or less, preferably 0.5% by weight or less, more preferably 0.3% by weight or less, based on the total weight of the monomers.

The system temperature in the polymerization reaction is usually −5 to 150 ° C., preferably 30 to 120 ° C., more preferably 50 to 110 ° C., and the reaction time is usually 0.1 to 50 hours, preferably 2 to 24 hours. Preferably, it is 3 to 20 hours, and the end point of the reaction is usually 5% by weight or less, preferably 1% by weight or less, more preferably 0.5% by weight based on the total amount of unreacted monomers used. This can be confirmed by:

The polymer (A1) contained in the vinyl resin (A) is a crosslinked polymer obtained by crosslinking the polymer (A1) with a polyepoxy compound (a′1) and / or a polyol compound (a′2). Also good.
In the crosslinked polymer, the polymer (A1) is preferably crosslinked using a crosslinking agent (A ′) having a reactive functional group that reacts with active hydrogen such as a carboxyl group in the polymer (A1). As the agent (A ′), it is preferable to use a polyepoxy compound (a′1) and / or a polyol compound (a′2).

Examples of the polyepoxy compound (a′1) include those having an epoxy equivalent of 80 to 2,500, such as glycidyl ether [bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, pyrogallol triglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol. Diglycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, glycerin triglycidyl ether, polyethylene glycol (Mw 200-2,000) diglycidyl ether, polypropylene glycol (Mw 200-2,000) diglycidyl ether, bisphenol Diglycidyl ether of 1-20 mol adduct of alkylene oxide of A and the like]; glycidyl ester ( Diglycidyl tartrate, triglycidyl trimellitate, diglycidyl dimer, diglycidyl adipate, etc.); glycidyl amine [N, N-diglycidyl aniline, N, N-diglycidyl toluidine, N, N, N ′, N′-tetraglycidyldiaminodiphenylmethane, N, N, N ′, N′-tetraglycidylxylylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ′ , N′-tetraglycidyl hexamethylenediamine, etc.]; aliphatic epoxides (epoxidized polybutadiene, epoxidized soybean oil, etc.); alicyclic epoxides (limonene dioxide, dicyclopentadiene dioxide, etc.).

Examples of the polyol compound (a′2) include low-molecular polyhydric alcohol {aliphatic or alicyclic diol having 2 to 20 carbon atoms [ethylene glycol (hereinafter abbreviated as EG), diethylene glycol (hereinafter abbreviated as DEG), propylene glycol] 1,3-butylene glycol, 1,4-butanediol (hereinafter abbreviated as 14BG), 1,6-hexanediol, 3-methylpentanediol, neopentyl glycol, 1,9-nonanediol, 1,4-dihydroxy Cyclohexane, 1,4-bis (hydroxymethyl) cyclohexane, 2,2-bis (4,4'-hydroxycyclohexyl) propane, etc.]; aromatic ring-containing diol having 8 to 15 carbon atoms [m- or p-xylylene glycol 1,4-bis (hydroxyethyl) benzene, etc.]; trio having 3 to 8 carbon atoms (Polyglycerol, trimethylolpropane, etc.); polyhydric alcohols having a valence of 4 or more [pentaerythritol, α-methylglucoside, sorbitol, xylit, mannitol, glucose, fructose, sucrose, dipentaerythritol, polyglycerol (degree of polymerization 2) And 20) etc.], and their alkylene (2 to 4 carbon atoms) oxide adducts (degree of polymerization 2 to 30).

The use amount of the cross-linking agent (A ′) is preferably the equivalent ratio of the active hydrogen-containing group in the polymer (A1) and the reactive functional group in the cross-linking agent (A ′) from the viewpoint of absorbing the electrolyte. Is an amount of 1: 0.01 to 1: 2, more preferably 1: 0.02 to 1: 1.

Examples of the method of crosslinking the polymer (A1) using the crosslinking agent (A ′) include a method in which the lithium ion battery active material is coated with a coating resin composed of the polymer (A1) and then crosslinked. Specifically, a lithium ion battery active material and a resin solution containing the polymer (A1) are mixed and removed to produce a coated active material in which the lithium ion battery active material is coated with a resin, and then a crosslinking agent. A method of coating a lithium ion battery active material with a cross-linked polymer by causing a solution containing (A ′) to be mixed with a coated active material and heating to cause solvent removal and a cross-linking reaction.
The heating temperature is preferably 70 ° C. or higher when the polyepoxy compound (a′1) is used as a crosslinking agent, and is preferably 120 ° C. or higher when the polyol compound (a′2) is used.

Urethane resin (B) is a resin obtained by reacting active hydrogen component (b1) and isocyanate component (b2).

The active hydrogen component (b1) preferably contains at least one selected from the group consisting of polyether diol, polycarbonate diol and polyester diol.

Polyether diols include polyoxyethylene glycol (hereinafter abbreviated as PEG), polyoxyethyleneoxypropylene block copolymer diol, polyoxyethyleneoxytetramethylene block copolymer diol; ethylene glycol, propylene glycol, 1,4-butanediol 1,6-hexamethylene glycol, neopentyl glycol, bis (hydroxymethyl) cyclohexane, 4,4'-bis (2-hydroxyethoxy) -diphenylpropane and other low molecular glycol ethylene oxide adducts; number average molecular weight 2 PEG of 1,000 or less and dicarboxylic acid [aliphatic dicarboxylic acid having 4 to 10 carbon atoms (for example, succinic acid, adipic acid, sebacic acid, etc.), aromatic dicarboxylic acid having 8 to 15 carbon atoms (for example, terephthalic acid, isophthalic acid, etc. And a mixture of two or more thereof.
When the polyether diol contains an oxyethylene unit, the content of the oxyethylene unit is preferably 20% by weight or more, more preferably 30% by weight or more, and further preferably 40% by weight or more.
Also included are polyoxypropylene glycol, polyoxytetramethylene glycol (hereinafter abbreviated as PTMG), polyoxypropyleneoxytetramethylene block copolymer diol, and the like.
Among these, PEG, polyoxyethyleneoxypropylene block copolymer diol, and polyoxyethyleneoxytetramethylene block copolymer diol are preferable, and PEG is particularly preferable.
Moreover, only 1 type of polyether diol may be used, and 2 or more types of these mixtures may be used.

Examples of the polycarbonate diol include polyhexamethylene carbonate diol.

Examples of the polyester diol include condensed polyester diols obtained by reacting low-molecular diols and / or polyether diols having a number average molecular weight of 1,000 or less with one or more of the aforementioned dicarboxylic acids, and lactones having 4 to 12 carbon atoms. And polylactone diols obtained by ring-opening polymerization. Examples of the low molecular diol include low molecular glycols exemplified in the section of the polyether diol. Examples of the polyether diol having a number average molecular weight of 1,000 or less include polyoxypropylene glycol and PTMG. Examples of the lactone include ε-caprolactone and γ-valerolactone. Specific examples of the polyester diol include polyethylene adipate diol, polybutylene adipate diol, polyneopentylene adipate diol, poly (3-methyl-1,5-pentylene adipate) diol, polyhexamethylene adipate diol, polycaprolactone diol. And mixtures of two or more thereof.

The active hydrogen component (b1) may be a mixture of two or more of the polyether diol, polycarbonate diol and polyester diol.

The active hydrogen component (b1) preferably contains a high molecular diol (b11) having a number average molecular weight of 2,500 to 15,000 as an essential component. Examples of the polymer diol (b11) include the polyether diol, polycarbonate diol, and polyester diol described above.
When the polymer diol (b11) has a number average molecular weight of 2,500 to 15,000, the hardness of the urethane resin (B) is moderately soft and the strength of the coating formed on the active material is increased. preferable.
The number average molecular weight of the polymer diol (b11) is more preferably from 3,000 to 12,500, and further preferably from 4,000 to 10,000.
The number average molecular weight of the polymer diol (b11) can be calculated from the hydroxyl value of the polymer diol.
The hydroxyl value can be measured according to the description of JIS K1557-1.

The active hydrogen component (b1) has a polymer diol (b11) having a number average molecular weight of 2,500 to 15,000 as an essential component, and the solubility parameter (SP value) of the polymer diol (b11) is 8.0 to It is preferably 12.0 (cal / cm ³ ) ^1/2 . The SP value of the polymer diol (b11) is more preferably 8.5 to 11.5 (cal / cm ³ ) ^1/2 , and 9.0 to 11.0 (cal / cm ³ ) ^1/2 . More preferably it is. The SP value of the polymer diol (b11) is preferably 8.0 to 12.0 (cal / cm ³ ) ^{1/2 from} the viewpoint of absorption of the electrolyte solution of the urethane resin (B).

In addition, the active hydrogen component (b1) has a polymer diol (b11) having a number average molecular weight of 2,500 to 15,000 as an essential component, and the content of the polymer diol (b11) is the weight of the urethane resin (B). From 20 to 80% by weight is preferable. The content of the polymer diol (b11) is more preferably 30 to 70% by weight, and further preferably 40 to 65% by weight.
The content of the polymer diol (b11) is preferably 20 to 80% by weight from the viewpoint of the absorption of the electrolyte solution of the urethane resin (B).

In addition, it is preferable that the active hydrogen component (b1) includes a polymer diol (b11) having a number average molecular weight of 2,500 to 15,000 and a chain extender (b13) as essential components.
Examples of the chain extender (b13) include low molecular diols having 2 to 10 carbon atoms (eg, EG, propylene glycol, 14BG, DEG, 1,6-hexamethylene glycol); diamines [fatty acids having 2 to 6 carbon atoms] Group diamines (eg, ethylene diamine, 1,2-propylene diamine, etc.), alicyclic diamines having 6 to 15 carbon atoms (eg, isophorone diamine, 4,4′-diaminodicyclohexylmethane, etc.), aromatic diamines having 6 to 15 carbon atoms (For example, 4,4′-diaminodiphenylmethane and the like); monoalkanolamine (for example, monoethanolamine and the like); hydrazine or a derivative thereof (for example, adipic acid dihydrazide) and a mixture of two or more of these. Among these, preferred are low molecular weight diols, and particularly preferred are EG, DEG and 14BG.
As a combination of the polymer diol (b11) and the chain extender (b13), a combination of PEG as the polymer diol (b11) and EG as the chain extender (b13), or as a polymer diol (b11) A combination of polycarbonate diol and EG as a chain extender (b13) is preferred.

The active hydrogen component (b1) includes a polymer diol (b11) having a number average molecular weight of 2,500 to 15,000, a diol (b12) other than the polymer diol (b11), and a chain extender (b13), The equivalent ratio [(b11) / (b12)] of (b11) and (b12) is 10/1 to 30/1, and the equivalent ratio of (b11) to the total equivalent of (b12) and (b13) { (B11) / [(b12) + (b13)]} is preferably 0.9 / 1 to 1.1 / 1.
The equivalent ratio [(b11) / (b12)] of (b11) and (b12) is more preferably 13/1 to 25/1, and further preferably 15/1 to 20/1.

The diol (b12) other than the polymer diol (b11) is a diol and is not included in the polymer diol (b11) described above, but is included in the low molecular diol having 2 to 10 carbon atoms of the chain extender (b13). If it does not have, it will not specifically limit, Specifically, the diol whose number average molecular weight is less than 2,500, and the diol whose number average molecular weight exceeds 15,000 are mentioned.
Examples of the diol include the polyether diol, polycarbonate diol, and polyester diol described above.

As the isocyanate component (b2), those conventionally used for polyurethane production can be used. Such isocyanates include aromatic diisocyanates having 6 to 20 carbon atoms (excluding carbon in the NCO group, the same shall apply hereinafter), aliphatic diisocyanates having 2 to 18 carbon atoms, alicyclic diisocyanates having 4 to 15 carbon atoms, Examples thereof include araliphatic diisocyanates having 8 to 15 carbon atoms, modified products of these diisocyanates (carbodiimide-modified products, urethane-modified products, uretdione-modified products, etc.) and mixtures of two or more of these.

Specific examples of the aromatic diisocyanate include 1,3- or 1,4-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate, 2,4′- or 4,4′-diphenylmethane diisocyanate (hereinafter referred to as “the aromatic diisocyanate”). Diphenylmethane diisocyanate is abbreviated as MDI), 4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanate And natodiphenylmethane and 1,5-naphthylene diisocyanate.

Specific examples of the aliphatic diisocyanate include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethylcaproate, Examples thereof include bis (2-isocyanatoethyl) carbonate and 2-isocyanatoethyl-2,6-diisocyanatohexanoate.

Specific examples of the alicyclic diisocyanate include isophorone diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, and bis (2-isocyanatoethyl) -4-cyclohexylene-1,2. -Dicarboxylate, 2,5- or 2,6-norbornane diisocyanate and the like.

Specific examples of the araliphatic diisocyanate include m- or p-xylylene diisocyanate, α, α, α ', α'-tetramethylxylylene diisocyanate, and the like.

Among these, preferred are aromatic diisocyanates and alicyclic diisocyanates, more preferred are aromatic diisocyanates, and still more preferred is MDI.

When the urethane resin (B) contains the polymer diol (b11) and the isocyanate component (b2), the equivalent ratio of (b2) / (b11) is preferably 10/1 to 30/1, more preferably 11/1. Is 28/1, more preferably 15/1 to 25/1. When the ratio of the isocyanate component (b2) exceeds 30 equivalents, a hard film is formed.
When the urethane resin (B) contains the polymer diol (b11), the chain extender (b13) and the isocyanate component (b2), the equivalent ratio of (b2) / [(b11) + (b13)] is usually 0. 0.9 / 1 to 1.1 / 1, preferably 0.95 / 1 to 1.05 / 1. If it is outside this range, the urethane resin may not have a sufficiently high molecular weight.

The number average molecular weight of the urethane resin (B) is preferably 40,000 to 500,000, more preferably 50,000 to 400,000, and further preferably 60,000 to 300,000. When the number average molecular weight of the urethane resin (B) is less than 40,000, the strength of the coating is low, and when it exceeds 500,000, the solution viscosity increases and a uniform coating may not be obtained.

The number average molecular weight of the urethane resin (B) is measured by GPC using dimethylformamide (hereinafter abbreviated as DMF) as a solvent and polyoxypropylene glycol as a standard substance. The sample concentration may be 0.25% by weight, the column stationary phase may be TSKgel SuperH2000, TSKgel SuperH3000, TSKgel SuperH4000 (both manufactured by Tosoh Corporation), and the column temperature may be 40 ° C.

The urethane resin (B) can be produced by reacting the active hydrogen component (b1) and the isocyanate component (b2).
For example, the polymer diol (b11) and the chain extender (b13) are used as the active hydrogen component (b1), and the isocyanate component (b2), the polymer diol (b11), and the chain extender (b13) are reacted simultaneously. Examples thereof include a shot method and a prepolymer method in which the polymer diol (b11) and the isocyanate component (b2) are reacted first and then the chain extender (b13) is reacted continuously.
The urethane resin (B) can be produced in the presence or absence of a solvent inert to the isocyanate group. Suitable solvents when used in the presence of a solvent include amide solvents [DMF, dimethylacetamide, N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP), etc.], sulfoxide solvents (dimethyl sulfoxide, etc.), ketone solvents Solvents (methyl ethyl ketone, methyl isobutyl ketone, etc.), aromatic solvents (toluene, xylene, etc.), ether solvents (dioxane, tetrahydrofuran, etc.), ester solvents (ethyl acetate, butyl acetate, etc.) and mixtures of two or more of these Is mentioned. Among these, amide solvents, ketone solvents, aromatic solvents, and mixtures of two or more thereof are preferable.

In the production of the urethane resin (B), the reaction temperature may be the same as that normally used for the urethanization reaction, and is usually 20 to 100 ° C. when a solvent is used, and usually 20 to 220 ° C. when no solvent is used. .

If necessary to promote the reaction, a catalyst usually used for polyurethane reaction [for example, amine-based catalyst (triethylamine, triethylenediamine, etc.), tin-based catalyst (dibutyltin dilaurate, etc.)] can be used.

Further, if necessary, a polymerization terminator [for example, monohydric alcohol (ethanol, isopropanol, butanol, etc.), monovalent amine (dimethylamine, dibutylamine, etc.), etc.] can be used.

Production of the urethane resin (B) can be carried out with a production apparatus usually employed in the industry. When no solvent is used, a manufacturing apparatus such as a kneader or an extruder can be used. The urethane resin (B) produced in this manner has a solution viscosity measured as a 30 wt% (solid content) DMF solution, which is usually 1,000 to 1,000,000 mPa · s / 20 ° C., which is practically preferable. Is 1,500 to 500,000 mPa · s / 20 ° C., and 5,000 to 100,000 mPa · s / 20 ° C. is more preferable in practical use.

Examples of the polyester resin (C) include a polycondensate of a polyol and a polycarboxylic acid.
Examples of the polyol include a diol (c1) and a trivalent or higher polyol (c2), and examples of the polycarboxylic acid include a dicarboxylic acid (c3) and a trivalent or higher polycarboxylic acid (c4). Among these, a non-linear polyester resin using a diol (c1) and a dicarboxylic acid (c3) together with a trivalent or higher polyol (c2) and / or a trivalent or higher polycarboxylic acid (c4) is preferable. A polyester resin composed of the four components c1), (c2), (c3), and (c4) is more preferable.

Examples of the diol (c1) include alkylene glycol (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, dodecanediol, etc.); alkylene ether glycol ( DEG, triethylene glycol, dipropylene glycol, PEG, polyoxypropylene glycol, PTMG, etc.); alicyclic diol (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, hydrogenated bisphenol F, etc.); bisphenols (bisphenol) A, bisphenol F, bisphenol S, etc.); alkylene oxide (EO, PO, butylene oxide, styrene oxide, α-olefin oxide, etc.) adduct of the above alicyclic diol; Alkylene oxide Nord acids (EO, PO, butylene oxide, styrene oxide, alpha-olefin oxide, etc.) adducts. Among these, preferred are alkylene glycols having 6 or more carbon atoms, alkylene oxide adducts of bisphenols, and alicyclic diols, and more preferred are additions of PO, butylene oxide, styrene oxide, α-olefin oxides of bisphenols. Products, alkylene glycols having 8 or more carbon atoms, hydrogenated bisphenol A, hydrogenated bisphenol F, and combinations thereof.

Examples of the trivalent or higher polyol (c2) include trihydric or higher polyhydric aliphatic alcohols (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); trisphenols (trisphenol PA, etc.) ); Novolak resins (phenol novolak, cresol novolak, etc.); alkylene oxide adducts of the above trisphenols; alkylene oxide adducts of the above novolac resins. Among these, preferred are trivalent to octavalent or higher polyhydric aliphatic alcohols and alkylene oxide adducts of novolac resins, and more preferred are alkylene oxide adducts of novolak resins.

Dicarboxylic acids (c3) include alkylene dicarboxylic acids (succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, octadecanedicarboxylic acid, dodecenylsuccinic acid, pentadecenylsuccinic acid, octadecenylsuccinic acid, dimer Acids); alkenylene dicarboxylic acids (maleic acid, fumaric acid, etc.); aromatic dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, etc.) and the like. Among these, preferred are alkylene dicarboxylic acids having 6 to 50 carbon atoms, alkenylene dicarboxylic acids having 6 to 50 carbon atoms, aromatic dicarboxylic acids having 8 to 20 carbon atoms, and combinations thereof, and more preferred are carbon atoms. An alkylene dicarboxylic acid having 7 to 50 carbon atoms and a combination thereof with an aromatic dicarboxylic acid having 8 to 20 carbon atoms, and more preferable are alkenyl succinic acids having 16 to 50 carbon atoms and those having 8 to 20 carbon atoms. A combination of aromatic dicarboxylic acids.

Examples of the trivalent or higher polycarboxylic acid (c4) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (trimellitic acid, pyromellitic acid, etc.), vinyl polymers of unsaturated carboxylic acids (styrene / maleic acid copolymer). Styrene / acrylic acid copolymer, α-olefin / maleic acid copolymer, styrene / fumaric acid copolymer, etc.). Of these, aromatic polycarboxylic acids having 9 to 20 carbon atoms are preferred, and trimellitic acid is more preferred.

In addition, as the dicarboxylic acid (c3) or the trivalent or higher polycarboxylic acid (c4), acid anhydrides or lower alkyl esters (methyl ester, ethyl ester, isopropyl ester, etc.) described above may be used.

Further, hydroxycarboxylic acid (c5) can be copolymerized with (c1), (c2), (c3) and (c4). Examples of the hydroxycarboxylic acid (c5) include hydroxystearic acid and hardened castor oil fatty acid.

The ratio of the polyol and the polycarboxylic acid is usually 2/1 to 1/2, preferably 1.5 / 1 to 1/1 / as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. 1.5, more preferably 1.3 / 1 to 1 / 1.3. The ratio of the trivalent or higher polyol (c2) and the trivalent or higher polycarboxylic acid (c4) is such that the sum of the number of moles of (c2) and (c4) is the sum of the number of moles of (c1) to (c4). In general, it is 0 to 40 mol%, preferably 3 to 25 mol%, more preferably 5 to 20 mol%. The molar ratio of (c2) to (c3) is usually 0/100 to 100/0, preferably 80/20 to 20/80, more preferably 70/30 to 30/70.

The polyester resin (C) has a number average molecular weight of 2,000 to 50,000, more preferably 3,000 to 45,000, and still more preferably 5,000 to 40,000. From the viewpoint of

The number average molecular weight of the polyester resin (C) is measured by GPC. The conditions of GPC used for the measurement of the number average molecular weight of a polyester resin (C) are the following conditions, for example.
Apparatus: HLC-8220GPC (liquid chromatograph manufactured by Tosoh Corporation)
Column: TSK gel Super H4000 + TSK gel Super H3000 + TSK gel Super H2000 (both manufactured by Tosoh Corporation)
Column temperature: 40 ° C
Detector: RI (Refractive Index)
Solvent: Tetrahydrofuran Flow rate: 0.6 ml / min Sample concentration: 0.25 wt%
Injection volume: 10 μl
Standard: Polystyrene (manufactured by Tosoh Corporation; TSK STANDARD POLYSTYRENE)

The polyester resin (C) can be obtained by dehydrating condensation of polycarboxylic acid and polyol by heating to 150 to 280 ° C. in the presence of a known esterification catalyst such as tetrabutoxytitanate or dibutyltin oxide. It is also effective to reduce the pressure in order to improve the reaction rate at the end of the reaction.

The polyamide resin (D) is not particularly limited, but includes a polymerized fatty acid (d1) containing at least 40% by weight of a tribasic acid having 54 carbon atoms, an aliphatic monocarboxylic acid (d2) having 2 to 4 carbon atoms, and ethylenediamine. A resin obtained by condensation polymerization of a polyamine (d3) composed of an aliphatic polyamine having 3 to 9 carbon atoms is preferred.

As the polymerized fatty acid (d1), for example, an unsaturated fatty acid such as oleic acid or linoleic acid or a lower alkyl ester thereof (1 to 3 carbon atoms) is polymerized, and then a dibasic acid component having 36 carbon atoms having high utility value is used. The residue after being collected by distillation, which is also called trimer acid, has the following composition, for example.
Monobasic acid having 18 carbon atoms: 0 to 5% by weight (preferably 0 to 2% by weight, more preferably 0 to 1% by weight)
C36 dibasic acid: less than 60% by weight (preferably less than 50% by weight, more preferably less than 40% by weight)
Tribasic acid having 54 carbon atoms: 40% by weight or more (preferably 50% by weight or more, more preferably 60% by weight or more)
If necessary, a part of (d1) may be replaced with other tribasic acid or tetrabasic acid. Examples of the other tribasic acid or tetrabasic acid include trimellitic acid, pyromellitic acid, benzophenone tetracarboxylic acid, and butanetetracarboxylic acid (including these acid anhydrides and alkyl esters having 1 to 3 carbon atoms). Etc.

Examples of the aliphatic monocarboxylic acid having 2 to 4 carbon atoms (d2) include acetic acid, propionic acid and butyric acid, which can be used alone or in a mixture at any ratio.

The amount of (d2) used is usually 20 to 40 equivalent%, preferably 24 to 36 equivalent%, more preferably 26 to 32 equivalent%, based on the total carboxylic acid component [(d1) + (d2)].

Examples of the aliphatic polyamine having 3 to 9 carbon atoms constituting the polyamine (d3) include diethylenetriamine, propylenediamine, diaminobutane, hexamethylenediamine, trimethylhexamethylenediamine, iminobispropylamine, and methyliminobispropylamine. . The (d3) is a mixture of at least one of ethylenediamine and an aliphatic polyamine having 3 to 9 carbon atoms, and the proportion of ethylenediamine in the (d3) is usually 60 to 85 equivalent%, preferably 70 to 80 equivalent%. It is.

The number average molecular weight of the polyamide resin (D) is usually 3,000 to 50,000, preferably 5,000 to 10,000, more preferably 6,000 to 9,000.

The number average molecular weight of the polyamide resin (D) can be determined by GPC measurement under the following conditions.
Apparatus: HLC-802A (manufactured by Tosoh Corporation)
Column: 2 TSK gel GMH6 (Tosoh Corporation)
Measurement temperature: 40 ° C
Sample solution: 0.25 wt% DMF solution injection amount: 200 μl
Detector: RI
Standard: Polystyrene (manufactured by Tosoh Corporation; TSK STANDARD POLYSTYRENE)

The melting point of the polyamide resin (D) measured by a trace melting point method (measured using a melting point measurement device according to the melting point measurement method specified in JIS K0064-1992, 3.2) is from the viewpoint of the heat resistance of the battery. The temperature is preferably 100 to 150 ° C, more preferably 120 to 130 ° C.

The polyamide resin (D) can be produced by the same method as the production method of ordinary polymerized fatty acid polyamide resin. The reaction temperature of the amidation condensation polymerization reaction is usually 160 to 250 ° C., preferably 180 to 230 ° C. The reaction is preferably performed in an inert gas such as nitrogen gas in order to prevent coloring, and at the end of the reaction, the reaction may be performed under reduced pressure in order to promote the completion of the reaction or the removal of volatile components. Further, after the amidation condensation polymerization reaction, the reaction product can be diluted with an alcohol solvent such as methanol, ethanol, isopropanol or the like to form a solution.

Examples of other resins (E) include epoxy resins, polyimide resins, silicone resins, phenol resins, melamine resins, urea resins, aniline resins, ionomer resins, polycarbonates, and the like.

The type of solvent that can be used in the resin solution varies depending on the type of coating resin. For example, amide solvents (DMF, dimethylacetamide, NMP, etc.), sulfoxide solvents (dimethyl sulfoxide, etc.), ketone solvents ( Methyl ethyl ketone, methyl isobutyl ketone, etc.), hydrocarbon solvents (n-hexane, cyclohexane, toluene, xylene, etc.), ether solvents (dioxane, tetrahydrofuran, etc.), ester solvents (ethyl acetate, butyl acetate, etc.), alcohol solvents [For example, methanol, ethanol, isopropanol (hereinafter abbreviated as IPA), octanol, etc.], water, and a mixture of two or more of these.

The resin solution can be prepared by a method such as adding a coating resin in a solvent and stirring, and the preparation method is not particularly limited.

The viscosity (25 ° C.) of the resin solution is preferably 0.1 to 10,000 mPa · s, preferably 1 to 8,000 mPa · s, from the viewpoint of uniformly coating the resin solution on the lithium ion battery active material. More preferred is 5 to 5,000 mPa · s.
Here, the viscosity of the resin solution refers to the rotor No. 7 is a numerical value when measured under the conditions of 25 ° C. and 6 rotations / minute.

The ratio of the resin solid content in the resin solution is preferably 10 to 40% by weight, more preferably 12 to 36% by weight, and 15 to 34% by weight from the viewpoint of securing an appropriate viscosity. More preferably.

By introducing the resin solution, the entire lithium ion battery active material can be coated with the resin solution. Further, it is preferable to add the resin solution while stirring.
The stirring conditions for charging the resin solution are not particularly limited, but are preferably stirred at a peripheral speed of 1 to 30 m / s, more preferably 5 to 25 m / s, and more preferably 8 to 20 m / s. More preferably, stirring is performed at s.
The peripheral speed in this specification is the speed of the tip of the stirring blade, and is calculated by the following equation.
V = π × Di × N ÷ 60
Where V is the blade circumferential speed (m / s), Di is the blade diameter (m) of the stirring blade, N is the rotational speed (rpm), and π is the circumferential ratio.
Examples of the apparatus for stirring include a stirrer, a universal mixer, and a planetary mixer.

The charging speed of the resin solution is not particularly limited, but it is preferable to add it little by little. When a large amount of the resin solution is added, the resin solution locally adheres to the lithium ion battery active material, and it becomes difficult to cover the entire lithium ion battery active material with the resin solution.
Examples of the method for charging the resin solution include dropping and pouring.
As a method for charging the resin solution based on the above conditions, for example, a method of dropping a resin solution having a resin solid content of 10 to 40% by weight over 1 to 90 minutes is preferable.
Moreover, it is preferable to perform stirring from the viewpoint of uniformly coating the resin solution on the lithium ion battery active material after the resin solution is added. The stirring conditions are preferably the same as the stirring conditions when charging the resin solution.

The input amount of the resin solution can be determined in consideration of the solid content weight of the coating resin contained in the resin solution, and the ratio of the solid content weight of the coating resin to the weight of the lithium ion battery active material is 0. 0.05 to 10% by weight, more preferably 0.5 to 10% by weight, still more preferably 0.8 to 5% by weight, and particularly preferably 1 to 3% by weight. preferable.

Further, from the viewpoint of uniformly covering the lithium ion battery active material with the resin solution, the ratio (V / S) of the volume V (cm ³ ) of the resin solution to the total surface area S (cm ² ) of the lithium ion battery active material is: It is preferably 0.0000001 to 0.0001, more preferably 0.000001 to 0.00008, and further preferably 0.00001 to 0.00006.
Here, the total surface area of the lithium ion battery active material is calculated from the product of the weight of the lithium ion battery active material used and the specific surface area. The specific surface area refers to the BET specific surface area.

(2) Next, a conductive aid is added.
Thereby, a conductive support agent can be made to adhere further to the circumference | surroundings of the lithium ion battery active material to which the resin solution adhered. On the other hand, if the conductive assistant is added before the resin solution is added, the conductive assistants aggregate together, making it difficult to attach the conductive assistant to the entire lithium ion battery active material.

The conductive auxiliary (X) is selected from materials having conductivity.
Specifically, metals [aluminum, stainless steel (SUS), silver, gold, copper, titanium, etc.], carbon [graphite and carbon black (acetylene black, ketjen black, furnace black, channel black, thermal lamp black, etc.), etc. , And mixtures thereof, but are not limited thereto.
These conductive auxiliary agents (X) may be used individually by 1 type, and may be used together 2 or more types. Further, these alloys or metal oxides may be used. From the viewpoint of electrical stability, aluminum, stainless steel, carbon, silver, gold, copper, titanium and mixtures thereof are preferred, silver, gold, aluminum, stainless steel and carbon are more preferred, and carbon is particularly preferred. is there. Moreover, as these conductive auxiliary agents (X), what coated the electroconductive material [a metal thing among the above-mentioned (X)] by plating etc. around the particulate ceramic material and the resin material may be used.

The shape (form) of the conductive auxiliary agent (X) is not limited to the particle form, and may be a form other than the particle form, and in a form that is practically used as a so-called filler-based conductive resin composition such as a carbon nanotube. There may be.

The average particle diameter of the conductive auxiliary agent (X) is not particularly limited, but is preferably 0.01 to 10 μm and more preferably 0.02 to 5 μm from the viewpoint of the electric characteristics of the battery. Preferably, it is 0.03 to 1 μm. In the present specification, “particle diameter” means the maximum distance L among the distances between any two points on the contour line of the conductive additive (X). The value of “average particle size” is the average value of the particle size of particles observed in several to several tens of fields using an observation means such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM). The calculated value shall be adopted.

The ratio of the conductive auxiliary agent to be added is preferably 0.5 to 15% by weight, more preferably 0.5 to 10% by weight, based on the weight of the lithium ion battery active material. 0.8 to 8% by weight is more preferable, and 1 to 5% by weight is particularly preferable.

The conductive auxiliary agent is preferably added while stirring, and the peripheral speed when the conductive auxiliary agent is added while stirring is preferably 9 to 90 m / s, more preferably 12 to 85 m / s. It is preferably 14 to 80 m / s.
Further, it is preferable to include a step of stirring at a peripheral speed of 9 to 90 m / s after adding the conductive auxiliary agent, more preferably a peripheral speed of 12 to 85 m / s, and 14 to 80 m / s. Is more preferable.

The solid content concentration when adding the conductive assistant is preferably 70 to 98% by weight, more preferably 80 to 97% by weight, and still more preferably 85 to 95% by weight.
The solid content concentration when the conductive auxiliary agent is added is the solid content concentration contained in the system of the system to which the conductive auxiliary agent is added (a mixture containing a lithium ion active material and a coating resin). It is the solid content concentration with respect to the total weight of the active material, coating resin, solvent and other components.
The solid content includes the lithium ion battery active material, the solid component of the coating resin, and the solid content contained in other components, and the solid content concentration is calculated from the total amount of the solid content.

(3) Subsequently, it is preferable to perform solvent removal.
Thereby, the covering active material for lithium ion batteries from which the solvent was removed from the surface can be obtained. In addition, from the viewpoint of uniform coating, it is preferable to remove the solvent while stirring after adding the conductive additive.
When the solvent is removed with stirring after the addition of the conductive assistant, the peripheral speed is preferably 2 to 50 m / s, more preferably 3 to 30 m / s, and more preferably 4 to 20 m / s. More preferably.

As a method for removing the solvent, a method of heating and drying the coated active material for a lithium ion battery after adding a conductive assistant, a method of drying the coated active material for a lithium ion battery after adding a conductive assistant under reduced pressure, Examples thereof include a method of freezing and drying a coating active material for a lithium ion battery after adding a conductive additive, and a combination of these methods.

The conditions for removing the solvent are not particularly limited. For example, after adding a conductive aid, the temperature is raised to 50 to 200 ° C. while stirring, the pressure is reduced to 0.007 to 0.04 MPa, and the mixture is held for 10 to 150 minutes. It is preferable to remove the solvent.

The coated active material may be pulverized after the solvent removal. Thereby, the aggregated particles can be pulverized. The method of pulverization is not particularly limited, but dry or wet is preferable. Examples of the dry pulverization include a jet mill. Examples of the wet pulverization include a high-speed shearing disperser, a sand grinder, and a bead mill.

Through the above steps, a coated active material for a lithium ion battery in which at least a part of the surface of the lithium ion battery active material is coated with a coating material containing a coating resin and a conductive additive can be produced.

The volume average particle diameter of the coated active material for a lithium ion battery produced by the production method of the present invention is preferably 1 to 80 μm, more preferably 1.2 to 35 μm, and more preferably 1.5 to 25 μm. Further preferred.

In the present specification, the volume average particle size of the coated active material for a lithium ion battery means a particle size (Dv50) at an integrated value of 50% in the particle size distribution determined by the microtrack method (laser diffraction / scattering method). The microtrack method is a method for obtaining a particle size distribution using scattered light obtained by irradiating particles with laser light. In addition, Nikkiso Co., Ltd. microtrack etc. can be used for the measurement of a volume average particle diameter.

An electrode for a lithium ion battery can be obtained using the above-described coated active material for a lithium ion battery.
Furthermore, a lithium ion battery such as a bipolar lithium ion battery can be obtained by using an electrode containing the above-described coated active material for a lithium ion battery.

Next, the present invention will be specifically described by way of examples. However, the present invention is not limited to the examples without departing from the gist of the present invention. Unless otherwise specified, “part” means “part by weight” and “%” means “% by weight”.

<Production Example 1>
A four-necked flask equipped with a stirrer, thermometer, reflux condenser, dropping funnel and nitrogen gas inlet tube was charged with 83 parts of ethyl acetate and 17 parts of methanol, and the temperature was raised to 68 ° C. Next, a monomer compounded liquid containing 242.8 parts of methacrylic acid, 97.1 parts of methyl methacrylate, 242.8 parts of 2-ethylhexyl methacrylate, 52.1 parts of ethyl acetate and 10.7 parts of methanol, and 2,2′- An initiator solution prepared by dissolving 0.263 parts of azobis (2,4-dimethylvaleronitrile) in 34.2 parts of ethyl acetate and stirring with a dropping funnel over 4 hours while blowing nitrogen into a four-necked flask. The radical polymerization was carried out by dropping continuously. After completion of the dropping, an initiator solution prepared by dissolving 0.583 parts of 2,2′-azobis (2,4-dimethylvaleronitrile) in 26 parts of ethyl acetate was continuously added using a dropping funnel over 2 hours. Furthermore, the polymerization was continued for 4 hours at the boiling point. After removing the solvent to obtain 582 parts of resin, 1,360 parts of isopropanol was added to obtain a vinyl resin (A) solution having a resin concentration of 30% by weight.

<Production Example 2>
In a four-necked flask equipped with a stirrer and a thermometer, 57.4 parts of PEG [manufactured by Sanyo Chemical Industries, Ltd.] having a number average molecular weight of 6,000 (calculated from the hydroxyl value), ethylene glycol (EG) 8.0 Part, MDI 34.7 part and DMF 233 part were prepared and reacted at 70 ° C. for 10 hours under a dry nitrogen atmosphere to obtain a urethane resin (B) solution having a resin concentration of 30% by weight and a viscosity of 60,000 mPa · s (20 ° C.). It was.

<Production Example 3>
In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, 673 parts of bisphenol A propylene oxide 2 mol adduct, 15 parts of propylene oxide 5 mol adduct of phenol novolac resin (number of nuclei of about 5), terephthalate 157 parts of acid, 37 parts of maleic anhydride, 152 parts of dodecenyl succinic anhydride and 2 parts of dibutyltin oxide were added, reacted at 220 ° C. under normal pressure for 8 hours, and further reacted at reduced pressure of 0.001 to 0.002 MPa for 5 hours. . Next, 32 parts of trimellitic anhydride was added thereto and reacted at 180 ° C. and normal pressure for 2 hours to obtain a polyester resin. Thereafter, DMF was added to obtain a polyester resin (C) solution having a resin concentration of 30% by weight.

<Production Example 4>
A four-necked flask equipped with a thermometer, a stirrer, a nitrogen introduction tube, and a dehydration exhaust tube was charged with polymerized fatty acid [monobasic acid: 1 to 2%, dibasic acid: 50 to 60%, tribasic acid: 42 to 45]. %; “Pripole 1046” manufactured by Unikema International] 203.7 parts (0.7 equivalents), 18 parts (0.3 equivalents) of acetic acid, 24 parts (0.8 equivalents) of ethylenediamine and 11.6 parts of hexamethylenediamine ( 0.2 equivalents) and reacted in a nitrogen gas atmosphere at 200 to 210 ° C. for 4 hours to obtain a light brown solid polyamide resin. Thereafter, NMP was added to obtain a polyamide resin (D) solution having a resin concentration of 30% by weight.

<Example 1>
96 parts of LiCoO ₂ powder (manufactured by Nippon Chemical Industry Co., Ltd., CELLSEED C-20F2, volume average particle diameter 19 μm) as an active material was placed in a universal mixer and stirred at room temperature at a peripheral speed of 11 m / s, Production Example 1 6.7 parts of the vinyl resin (A) solution obtained in (2 parts of resin solid content) was dropped and mixed over 60 minutes, and further stirred at a peripheral speed of 11 m / s for 10 minutes.
Next, in a state of stirring at a peripheral speed of 26 m / s, 2 parts of acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd.) as a conductive auxiliary agent was added in three portions, and after the addition of the conductive auxiliary agent, stirring was continued. The speed was maintained at 26 m / s and mixed for 5 minutes.
Next, the peripheral speed of stirring was changed to 5 m / s, the temperature was raised to 70 ° C. while stirring for 5 minutes, the pressure was reduced to 0.01 MPa while maintaining the peripheral speed of stirring at 5 m / s, and maintained for 30 minutes. Solvent was performed. A coated active material was obtained by the above operation.
In addition, the solid content concentration at the time of adding the conductive assistant was 95% by weight.
When the volume average particle diameter of the coated active material was measured using a microtrack (manufactured by Nikkiso Co., Ltd., 9320-X100, the same applies hereinafter), it was 57 μm.
The ratio (V / S) of the volume V (cm ³ ) of the resin solution used for the production of the coated active material to the total surface area S (cm ² ) of the lithium ion battery active material is calculated by the following method, and the value is It is shown in Table 1.
Using this coated active material, evaluation of electron conductivity and observation with an electron microscope were performed by the following methods. The results are shown in Table 1.

<Examples 2 to 5>
In Example 1, when adding acetylene black and after adding acetylene black, the peripheral speeds of stirring were 10 m / s, 15 m / s, 60 m / s, and 85 m / s, respectively, as shown in Table 1. A coated active material was obtained in the same manner as in Example 1 except for the change.
About these coating | coated active materials, calculation of ratio (V / S), evaluation of electronic conductivity, and observation with an electron microscope were performed similarly to Example 1, and the result was shown in Table 1. The results of measuring the volume average particle diameter of the coated active material are shown in Table 1.

<Examples 6 to 8>
In Example 1, the coated active material was obtained in the same manner as in Example 1 except that the peripheral speed of stirring during desolvation was changed to 10 m / s, 20 m / s, and 40 m / s as shown in Table 1, respectively. It was.
About these coating | coated active materials, calculation of ratio (V / S), evaluation of electronic conductivity, and observation with an electron microscope were performed similarly to Example 1, and the result was shown in Table 1. The results of measuring the volume average particle diameter of the coated active material are shown in Table 1.

<Example 9>
96 parts of LiCoO ₂ powder (manufactured by Nippon Chemical Industry Co., Ltd., CELLSEED C-20F2, volume average particle diameter 19 μm) as an active material was placed in a universal mixer and stirred at room temperature at a peripheral speed of 11 m / s, Production Example 1 6.7 parts of the vinyl resin (A) solution obtained in (2 parts of resin solid content) was dropped and mixed over 60 minutes, and further stirred at a peripheral speed of 11 m / s for 10 minutes.
Next, in a state of stirring at a peripheral speed of 26 m / s, 2 parts of acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd.) as a conductive auxiliary agent was added in three portions, and after the addition of the conductive auxiliary agent, stirring was continued. The speed was maintained at 26 m / s and mixed for 5 minutes.
Next, stirring was stopped, and the temperature was raised to 70 ° C. while standing still, and the pressure was reduced to 0.01 MPa and maintained for 30 minutes to remove the solvent. A coated active material was obtained by the above operation.
For this coated active material, calculation of the ratio (V / S), evaluation of electron conductivity, and observation with an electron microscope were carried out in the same manner as in Example 1, and the results are shown in Table 1. The results of measuring the volume average particle diameter of the coated active material are shown in Table 1.

<Example 10>
96 parts of LiCoO ₂ powder (manufactured by Nippon Chemical Industry Co., Ltd., CELLSEED C-20F2, volume average particle diameter 19 μm) as an active material was placed in a universal mixer and stirred at room temperature at a peripheral speed of 11 m / s, Production Example 1 6.7 parts of the vinyl resin (A) solution obtained in (2 parts of resin solid content) and 16.7 parts of a solution prepared by previously mixing 10 parts of isopropanol were added dropwise over 60 minutes, and the peripheral speed was 11 m / s. Stir for 10 minutes.
Thereafter, a coated active material was obtained in the same manner as in Example 1.
For this coated active material, calculation of the ratio (V / S), evaluation of electron conductivity, and observation with an electron microscope were carried out in the same manner as in Example 1, and the results are shown in Table 1. The results of measuring the volume average particle diameter of the coated active material are shown in Table 1.
In addition, the solid content concentration at the time of adding a conductive support agent was 87 weight%.

<Example 11>
96 parts of LiCoO ₂ powder (manufactured by Nippon Chemical Industry Co., Ltd., CELLSEED C-20F2, volume average particle diameter 19 μm) as an active material was placed in a universal mixer and stirred at room temperature at a peripheral speed of 11 m / s, Production Example 1 6.7 parts of the vinyl resin (A) solution obtained in (2 parts of resin solids) and 31.7 parts of a solution prepared by previously mixing 25 parts of isopropanol were added dropwise over 60 minutes, and the peripheral speed was 11 m / s. Stir for 10 minutes.
Thereafter, a coated active material was obtained in the same manner as in Example 1.
For this coated active material, calculation of the ratio (V / S), evaluation of electron conductivity, and observation with an electron microscope were carried out in the same manner as in Example 1, and the results are shown in Table 1. The results of measuring the volume average particle diameter of the coated active material are shown in Table 1.
The solid content concentration when the conductive auxiliary agent was added was 77% by weight.

<Example 12>
96 parts of LiCoO ₂ powder (manufactured by Nippon Chemical Industry Co., Ltd., CELLSEED C-20F2, volume average particle size 19 μm) as an active material was placed in a universal mixer and stirred at room temperature at a peripheral speed of 4 m / s, Production Example 1 6.7 parts of the vinyl resin (A) solution obtained in (2 parts of resin solids) was added dropwise and mixed over 60 minutes, and further stirred at a peripheral speed of 4 m / s for 10 minutes.
Thereafter, a coated active material was obtained in the same manner as in Example 1.
For this coated active material, calculation of the ratio (V / S), evaluation of electron conductivity, and observation with an electron microscope were carried out in the same manner as in Example 1, and the results are shown in Table 1. The results of measuring the volume average particle diameter of the coated active material are shown in Table 1.

<Example 13>
96 parts of LiCoO ₂ powder (manufactured by Nippon Chemical Industry Co., Ltd., CELLSEED C-20F2, volume average particle diameter 19 μm) as an active material was placed in a universal mixer and stirred at room temperature at a peripheral speed of 7 m / s, Production Example 1 6.7 parts of the vinyl resin (A) solution obtained in (2 parts of resin solids) was dropped and mixed over 60 minutes, and further stirred at a peripheral speed of 7 m / s for 10 minutes.
Thereafter, a coated active material was obtained in the same manner as in Example 1.
For this coated active material, calculation of the ratio (V / S), evaluation of electron conductivity, and observation with an electron microscope were carried out in the same manner as in Example 1, and the results are shown in Table 1. The results of measuring the volume average particle diameter of the coated active material are shown in Table 1.

<Example 14>
A coated active material was prepared in the same manner as in Example 1 except that 92 parts of LiCoO ₂ powder, 13.3 parts of vinyl resin (A) solution (4 parts of resin solid content), and 4 parts of acetylene black were used.
It was 72 micrometers when the volume average particle diameter of the coating active material was measured using the micro track.
For this coated active material, calculation of the ratio (V / S), evaluation of electron conductivity, and observation with an electron microscope were carried out in the same manner as in Example 1, and the results are shown in Table 1.

<Example 15>
98.9 parts of LiCoO ₂ powder (manufactured by Nippon Chemical Industry Co., Ltd., CELLSEED C-20F2, volume average particle diameter 19 μm) as an active material is placed in a universal mixer and manufactured with stirring at room temperature and a peripheral speed of 11 m / s. 0.34 parts of the vinyl resin (A) solution obtained in Example 1 (resin solid content 0.1 part) and 10.34 parts of a solution prepared by previously mixing 10 parts of isopropanol were dropped and mixed over 60 minutes, and the peripheral speed was further increased. The mixture was stirred at 11 m / s for 10 minutes.
Next, with stirring at a peripheral speed of 26 m / s, 1 part of acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd.) as a conductive auxiliary agent was added in three portions, and after the addition of the conductive auxiliary agent, stirring was continued. The speed was maintained at 26 m / s and mixed for 5 minutes.
Thereafter, a coated active material was obtained in the same manner as in Example 1.
For this coated active material, calculation of the ratio (V / S), evaluation of electron conductivity, and observation with an electron microscope were carried out in the same manner as in Example 1, and the results are shown in Table 1. The results of measuring the volume average particle diameter of the coated active material are shown in Table 1.

<Example 16>
A coated active material was prepared in the same manner as in Example 1 except that 83 parts of LiCoO ₂ powder, 16.7 parts of vinyl resin (A) solution (5 parts of resin solid content), and 12 parts of acetylene black were used.
For this coated active material, calculation of the ratio (V / S), evaluation of electron conductivity, and observation with an electron microscope were carried out in the same manner as in Example 1, and the results are shown in Table 1. The results of measuring the volume average particle diameter of the coated active material are shown in Table 1.

<Examples 17 to 19>
In place of the vinyl resin solution, the urethane resin (B) solution obtained in Production Example 2, the polyester resin (C) solution obtained in Production Example 3, and the polyamide resin (D) solution obtained in Production Example 4 were used. A coated active material was prepared in the same manner as in Example 1.
When the volume average particle diameter of the coated active material was measured using Microtrac, they were 62 μm, 64 μm, and 59 μm, respectively.
About these coating | coated active materials, calculation of ratio (V / S), evaluation of electronic conductivity, and observation with an electron microscope were performed similarly to Example 1, and the result was shown in Table 1.

<Example 20>
Other than changing the LiCoO ₂ powder of Example 1 (Nippon Chemical Industry Co., Ltd., CELLSEED C-20F2) to LiCoO ₂ powder (Nippon Chemical Industry Co., Ltd., CELLSEED C-5H, volume average particle diameter 6.5 μm). Produced a coated active material in the same manner as in Example 1.
For this coated active material, calculation of the ratio (V / S), evaluation of electron conductivity, and observation with an electron microscope were carried out in the same manner as in Example 1, and the results are shown in Table 1. The results of measuring the volume average particle diameter of the coated active material are shown in Table 1.

<Example 21>
Other than changing the LiCoO ₂ powder of Example 15 (Nippon Chemical Industry Co., Ltd., CELLSEED C-20F2) to LiCoO ₂ powder (Nippon Chemical Industry Co., Ltd., CELLSEED C-5H, volume average particle size 6.5 μm). Produced a coated active material in the same manner as in Example 15.
For this coated active material, calculation of the ratio (V / S), evaluation of electron conductivity, and observation with an electron microscope were carried out in the same manner as in Example 1, and the results are shown in Table 1. The results of measuring the volume average particle diameter of the coated active material are shown in Table 1.

<Comparative Example 1>
Put vinyl resin (A) solution 6.7 parts obtained in Production Example 1 (resin solid content 2 parts) in a universal mixer, at room temperature, with stirring state at a peripheral speed of 11m / s, LiCoO ₂ powder (Nippon Chemical Industrial 96 parts of CELLSEED C-20F2, volume average particle diameter 19 μm, manufactured by Co., Ltd. were added, and the mixture was further stirred for 10 minutes at a peripheral speed of 11 m / s.
Next, 2 parts of acetylene black was added in three portions while stirring at a peripheral speed of 26 m / s, and the mixture was mixed for 5 minutes while maintaining the peripheral speed of stirring at 26 m / s even after the addition of the conductive aid.
Next, the peripheral speed of stirring was changed to 5 m / s, the temperature was raised to 70 ° C. while stirring for 5 minutes, the pressure was reduced to 0.01 MPa while maintaining the peripheral speed of stirring at 5 m / s, and maintained for 30 minutes. Solvent was performed. A coated active material was obtained by the above operation.
It was 95 micrometers when the volume average particle diameter of the coating active material was measured using the micro track.
For this coated active material, calculation of the ratio (V / S), evaluation of electron conductivity, and observation with an electron microscope were carried out in the same manner as in Example 1, and the results are shown in Table 1.

<Comparative example 2>
96 parts of LiCoO ₂ powder (manufactured by Nippon Kagaku Kogyo Co., Ltd., CELLSEED C-20F2, volume average particle diameter 19 μm) is placed in a universal mixer and stirred at room temperature and a peripheral speed of 11 m / s, and 2 parts of acetylene black is 3 parts. The mixture was divided into two times and further stirred at a peripheral speed of 11 m / s for 10 minutes.
Subsequently, the peripheral speed of stirring was changed to 26 m / s, and 6.7 parts of the vinyl resin (A) solution obtained in Production Example 1 (2 parts of resin solid content) was dropped and mixed over 60 minutes while stirring. .
Next, the peripheral speed of stirring was changed to 5 m / s, the temperature was raised to 70 ° C. while stirring for 5 minutes, the pressure was reduced to 0.01 MPa, and the solvent was removed for 30 minutes. A coated active material was obtained by the above operation.
It was 45 micrometers when the volume average particle diameter of the coating active material was measured using the micro track.
For this coated active material, calculation of the ratio (V / S), evaluation of electron conductivity, and observation with an electron microscope were carried out in the same manner as in Example 1, and the results are shown in Table 1.

<Comparative Example 3>
The resin solution and acetylene black were not used, and no coated active material was produced.
Using an uncoated active material [LiCoO ₂ powder (manufactured by Nippon Chemical Industry Co., Ltd., CELLSEED C-20F2, volume average particle diameter 19 μm)], the electronic conductivity was evaluated by the following method. The results are shown in Table 1.

<Comparative example 4>
The resin solution and acetylene black were not used, and no coated active material was produced.
Using the uncoated active material [LiCoO ₂ powder (manufactured by Nippon Chemical Industry Co., Ltd., CELLSEED C-5H, volume average particle size 6.5 μm)], the electronic conductivity was evaluated by the following method. The results are shown in Table 1.

[Ratio (V / S) of resin solution volume V (cm ³ ) to total surface area S (cm ² ) of lithium ion battery active material]
The volume V (cm ³ ) of the resin solution was obtained by measuring the density (cm ³ / g) of the resin solution using a measuring flask and calculating the product of the weight (g) of the resin solution used and the density.
The total surface area S (cm ² ) of the lithium ion battery active material is determined by measuring the BET specific surface area (cm ² / g) of the lithium ion battery active material under the following conditions, and the weight (g ) And the BET specific surface area.
Using the calculated V and S, the ratio (V / S) of the volume V (cm ³ ) of the resin solution to the total surface area S (cm ² ) of the lithium ion battery active material was calculated. The results are shown in Table 1.
<Measurement conditions of BET specific surface area>
Measuring device: Micromeritex ASAP-2010
Adsorption gas: N ₂
Dead volume measuring gas: He
Adsorption temperature: 77K (liquid nitrogen temperature)
Pre-measurement treatment: vacuum drying at 200 ° C. for 12 hours (set on measurement stage after He purge)
Measurement mode: Isothermal adsorption process and desorption process Measurement relative pressure P / P0 about 0 to 0.99
Equilibrium setting time: 180 sec per relative pressure

[Evaluation of electronic conductivity 1: DC resistance between active materials]
The direct current resistance between the active materials was measured as an index of electronic conductivity, and the results are shown in Table 1. In the following description, “active material” is the coated active material obtained in Examples 1 to 21 and Comparative Examples 1 or 2, or the active material used in Comparative Example 3 or 4.
30 mg of the active material was put inside a polypropylene cylinder having an inner diameter of 15 mm and a height of 30 mm, and tapped 50 times. The active material was further sandwiched between SUS316 cylinders, and a pressure of 100 kN was applied. The cylinder was removed, and the upper and lower resistance values of the active material formed into a cylindrical lump shape were measured using an electrochemical measuring device (1280C manufactured by Solartron).

[Electron conductivity evaluation 2: DC resistance reduction rate]
Using the value of the direct current resistance between the active materials, the reduction rate of the direct current resistance between the active materials before and after coating was calculated by the following formula, and the results are shown in Table 1. The larger the reduction rate, the greater the effect of the coating process.
[DC resistance decrease rate (%)] = {[DC resistance of active material before coating treatment (Ω)] − [DC resistance of coated active material (Ω)]} ÷ [DC resistance of active material before coating treatment] (Ω)] × 100
As the DC resistance value of the active material before the coating treatment, the DC resistance value of the active material of Comparative Example 3 is used for Examples 1 to 19, and the active material of Comparative Example 4 is used for Examples 20 and 21. The DC resistance value of the material was used.

[Observation with electron microscope]
Using a scanning electron microscope (SEM, Hitachi High-Technologies S-4800), the state of the particles of the coated active material obtained in Examples 1-21 and Comparative Examples 1-2 was observed, and the results are shown in Table 1. It was described in.

The “resin solution charging conditions” section of Table 1 shows the peripheral speed of stirring when charging the resin solution, the solid content concentration when charging the conductive assistant, and the stirring after adding the conductive assistant. The peripheral speed was also summarized in the item “Conductive auxiliary agent charging conditions”. The "desolvent conditions" section shows the peripheral speed of stirring during desolvation. In Example 9, since stirring was not performed during the solvent removal, it was determined to be “static drying”.
The “coated active material particle diameter” shown in Table 1 is the volume average particle diameter of the coated active material.
From the results shown in Table 1, by coating the surface of the lithium ion battery active material with a coating resin and a conductive additive, the direct current resistance between the active materials can be reduced, and the electron conductivity can be improved. You can see that In particular, by producing a coating active material for a lithium ion battery by the production method of the present invention, the surface of the lithium ion battery active material can be uniformly coated with the coating resin and the conductive auxiliary agent, and the electron conductivity is further improved. It turns out that it improves.

The coated active material for a lithium ion battery obtained by the present invention is particularly useful as an active material for a mobile phone, a personal computer and a hybrid vehicle, a bipolar secondary battery and a lithium ion secondary battery used for an electric vehicle. It is.

Claims (11)

1. A method for producing a coating active material for a lithium ion battery, wherein at least part of the surface of the lithium ion battery active material is coated with a coating agent containing a coating resin and a conductive auxiliary agent,
   A method for producing a coating active material for a lithium ion battery, comprising adding a resin solution containing the coating resin in the presence of the lithium ion battery active material and then adding the conductive additive.
2. 2. The method for producing a coated active material for a lithium ion battery according to claim 1, wherein the coated active material for the lithium ion battery has a volume average particle diameter of 1 to 80 μm.
3. The method for producing a coated active material for a lithium ion battery according to claim 1 or 2, wherein a solid content concentration when the conductive auxiliary agent is added is 70 to 98% by weight.
4. The ratio (V / S) of the volume V (cm ³ ) of the resin solution to the total surface area S (cm ² ) of the lithium ion battery active material is 0.0000001 to 0.0001. The manufacturing method of the covering active material for lithium ion batteries as described in any one of.
5. The coating for a lithium ion battery according to any one of claims 1 to 4, wherein the ratio of the solid content weight of the coating resin contained in the resin solution to the weight of the lithium ion battery active material is 0.05 to 10% by weight. A method for producing an active material.
6. The method for producing a coated active material for a lithium ion battery according to any one of claims 1 to 5, wherein a ratio of the weight of the conductive additive to the weight of the lithium ion battery active material is 0.5 to 15% by weight.
7. The method for producing a coated active material for a lithium ion battery according to any one of claims 1 to 6, further comprising a step of stirring at a peripheral speed of 9 to 90 m / s after adding the conductive assistant.
8. The method for producing a coated active material for a lithium ion battery according to any one of claims 1 to 7, further comprising a step of removing the solvent after adding the conductive assistant.
9. The method for producing a coated active material for a lithium ion battery according to claim 8, wherein after the addition of the conductive aid, the solvent removal is performed with stirring at a peripheral speed of 2 to 50 m / s.
10. The method for producing a coated active material for a lithium ion battery according to any one of claims 1 to 9, wherein a resin solution containing the coated resin is added while stirring in the presence of the lithium ion battery active material.
11. The method for producing a coated active material for a lithium ion battery according to claim 10, wherein the peripheral speed of stirring when the resin solution containing the coating resin is added is 1 to 30 m / s.