WO2015046191A1

WO2015046191A1 - Binder for nonaqueous secondary batteries, resin composition for nonaqueous secondary batteries, nonaqueous secondary battery separator, nonaqueous secondary battery electrode, and nonaqueous secondary battery

Info

Publication number: WO2015046191A1
Application number: PCT/JP2014/075176
Authority: WO
Inventors: 和也木村; 由照大島; 北本　剛
Original assignee: 東洋インキＳｃホールディングス株式会社; トーヨーケム株式会社
Priority date: 2013-09-24
Filing date: 2014-09-24
Publication date: 2015-04-02
Also published as: CN105531854B; JP2015088484A; KR101868240B1; JP5708872B1; CN105531854A; KR20160061317A

Abstract

This binder for nonaqueous secondary batteries contains a plurality of particles that are configured from a polymer, and is characterized in that the polymer is obtained by copolymerizing a first monomer containing an acidic functional group, a second monomer containing an amide group and a third monomer that is different from the first monomer, the second monomer and (meth)acrylonitrile, and has a glass transition temperature of from -60°C to 60°C. In addition, it is preferable that the polymer is obtained by copolymerizing 0.1-5% by weight of the first monomer, 0.1-5% by weight of the second monomer and 90-99.8% by weight of the third monomer relative to 100% by weight of the first to third monomers in total. Consequently, the present invention is able to provide a binder for nonaqueous secondary batteries, which has excellent safety during the production procedure and does not easily create health hazards, while having excellent electrolyte solution resistance and good adhesion to an electrode and a separator (especially, to a polyolefin layer).

Description

Nonaqueous secondary battery binder, nonaqueous secondary battery resin composition, nonaqueous secondary battery separator, nonaqueous secondary battery electrode and nonaqueous secondary battery

The present invention relates to a binder for a non-aqueous secondary battery that can be used to form a protective layer for an electrode of a non-aqueous secondary battery such as a lithium ion secondary battery and a protective layer for a separator. The present invention also provides a resin composition for non-aqueous secondary batteries containing such a binder for non-aqueous secondary batteries, and a non-aqueous secondary battery separator provided with a protective layer formed from the resin composition for non-aqueous secondary batteries. And a non-aqueous secondary battery electrode, and a non-aqueous secondary battery including at least one of the non-aqueous secondary battery separator and the non-aqueous secondary battery electrode.

Among non-aqueous secondary batteries, lithium ion secondary batteries (hereinafter referred to as “LIB”) can be used in mobile applications such as laptop computers and smartphones because they can obtain high output. LIB has also begun to be used in automotive applications in recent years.

LIB includes, for example, a separator made of polyolefin in order to avoid electrical contact between the positive electrode and the negative electrode and allow ions in the electrolyte to pass through. However, when the LIB (battery) becomes high temperature, the polyolefin separator melts, so that both electrodes are short-circuited, and the LIB (battery) may explode. Therefore, in order to prevent the short circuit, the separator is generally provided with a protective layer formed mainly of an inorganic filler.

Patent Document 1 discloses a protective layer using a rubbery polymer containing acrylonitrile as a binder for the protective layer.

Patent Document 2 discloses a protective layer in which core-shell polymer particles synthesized using acrylonitrile as one of raw materials are used as a binder for the protective layer.

JP 2005-235508 A WO2011 / 040474

Conventionally, acrylonitrile used to synthesize protective layer binders is highly toxic and difficult to handle. For this reason, the development of a protective layer binder that does not use acrylonitrile as a raw material has been required in consideration of the safety and health hazards of workers who produce the protective layer binder. However, a protective layer binder that is excellent in durability (hereinafter referred to as “electrolytic solution resistance”) that is not easily deteriorated by an electrolytic solution and that can satisfy high adhesion to an electrode and a separator (particularly, a polyolefin layer) has not been obtained. There is a problem.

Accordingly, an object of the present invention is to provide a non-aqueous solution that is excellent in electrolytic solution resistance, has good adhesion to electrodes and separators (particularly, a polyolefin layer), is excellent in safety during production, and hardly causes health damage. It is to provide a binder for a secondary battery.

Another object of the present invention is to provide a nonaqueous secondary battery resin composition containing such a nonaqueous secondary battery binder, and a nonaqueous secondary battery comprising a protective layer formed from the nonaqueous secondary battery resin composition. Another object of the present invention is to provide a battery separator and a non-aqueous secondary battery electrode, and a non-aqueous secondary battery including at least one of these non-aqueous secondary battery separator and non-aqueous secondary battery electrode.

The binder for a non-aqueous secondary battery of the present invention includes a plurality of particles composed of a polymer, and the polymer includes a first monomer containing an acidic functional group, a second monomer containing an amide group, It is characterized in that it is obtained by copolymerizing a first monomer, a second monomer, and a third monomer different from (meth) acrylonitrile, and has a glass transition temperature of −60 ° C. to 60 ° C.

According to the present invention, a polymer (a binder for a non-aqueous secondary battery) having a glass transition temperature (hereinafter referred to as “Tg”) in a predetermined range obtained by using a second monomer containing an amide group is used. To do. For this reason, the protective layer formed from the resin composition for non-aqueous secondary batteries containing such a polymer is excellent in durability (electrolytic solution resistance) that is not easily deteriorated by the electrolytic solution, and is provided with electrodes and separators (particularly polyolefins). Good adhesion to the separator formed) is obtained.

Furthermore, the binder (polymer) for non-aqueous secondary batteries of the present invention is produced (synthesized) without using (meth) acrylonitrile as a raw material. For this reason, the safety | security at the time of manufacturing the binder for non-aqueous secondary batteries improves, and the effect that a health hazard hardly arises is also acquired.

FIG. 1 is a longitudinal sectional view showing an embodiment of the LIB of the present invention.

According to the present invention, the binder for a non-aqueous secondary battery is excellent in electrolytic solution resistance and has good adhesion to electrodes and separators (especially polyolefin layers), and is excellent in safety during production and hardly causes health hazards. Can be provided.

Hereinafter, the binder for non-aqueous secondary battery, the resin composition for non-aqueous secondary battery, the non-aqueous secondary battery separator, the non-aqueous secondary battery electrode and the non-aqueous secondary battery according to the present invention will be described in detail.

The binder for non-aqueous secondary batteries of the present invention includes a plurality of particles composed of a polymer having a Tg of −60 ° C. to 60 ° C. (hereinafter sometimes referred to as “polymer particles”). In addition, this polymer includes a first monomer containing an acidic functional group (hereinafter simply referred to as “first monomer”) and a second monomer containing an amide group (hereinafter simply referred to as “second monomer”). And a third monomer different from (meth) acrylonitrile (hereinafter, simply referred to as “third monomer”), and obtained by copolymerization of the first monomer, the second monomer, and (meth) acrylonitrile. It is characterized by.

The method for copolymerizing these monomers is not particularly limited, but in general, emulsion polymerization or suspension polymerization is preferable. Thereby, a particulate polymer can be obtained more reliably. Hereinafter, a mixture of the first monomer, the second monomer, and the third monomer may be referred to as a “monomer mixture”.

The binder for a non-aqueous secondary battery of the present invention is preferably used as a protective layer for an electrode of a non-aqueous secondary battery and a separator, and more preferably used as a protective layer for a separator. In addition, a non-aqueous secondary battery is a secondary battery which does not use water for electrolyte solution, for example, a lithium ion secondary battery (LIB), a sodium ion secondary battery, a magnesium secondary battery etc. are mentioned. As will be described later, in this specification, LIB is described as an example of a non-aqueous secondary battery. However, the non-aqueous secondary battery of the present invention includes a non-aqueous secondary battery, a non-aqueous secondary battery other than LIB. Needless to say, a resin composition for a secondary battery, a non-aqueous secondary battery separator, and a non-aqueous secondary battery electrode can be applied.

The non-aqueous secondary battery resin composition of the present invention can be obtained by blending the non-aqueous secondary battery binder of the present invention with an inorganic filler. And the protective layer which uses the said resin composition for non-aqueous secondary batteries can be formed on the compound-material layer of the electrode mentioned later. Moreover, the protective layer which uses the said resin composition for non-aqueous secondary batteries can be formed on a separator (for example, polyolefin layer). By these protective layers, when the non-aqueous secondary battery is overheated, a short circuit occurs between both electrodes, and the risk of the non-aqueous secondary battery exploding can be reduced. Furthermore, these protective layers can also suppress damage to electrodes and separators caused by dendritic particles produced in the electrolyte.

The binder for a non-aqueous secondary battery of the present invention includes a plurality of polymer particles composed of a polymer obtained by copolymerizing a monomer mixture. These polymer particles are blended with an inorganic filler to produce a resin composition for a non-aqueous secondary battery, and then applied to an electrode and a separator (for example, a polyolefin layer). Functions to adhere. Therefore, it is important that the binder for non-aqueous secondary batteries is particles. On the other hand, when forming a protective layer using a linear polymer, there exists a possibility of filling the clearance gap between inorganic fillers. As a result, when a protective layer using a linear polymer is formed on an electrode or a separator, free movement of ions or the like between both electrodes is hindered. For this reason, when a linear polymer is used, the battery performance of LIB tends to deteriorate.

In the present invention, the polymer particles are polymers having a Tg of −60 ° C. to 60 ° C. obtained by copolymerizing a monomer mixture containing a first monomer, a second monomer, and a third monomer. Composed. The polymer particles have improved electrolyte resistance due to the presence of the amide group, and further improved affinity with the inorganic filler, thereby improving the solution stability of the resin composition for non-aqueous secondary batteries containing them. Furthermore, since the inorganic filler has good affinity with the polymer particles, it is uniformly dispersed in the non-aqueous secondary battery resin composition. For this reason, when a protective layer using such a resin composition for a non-aqueous secondary battery is used, for example, when a non-aqueous secondary battery is created by winding them in a spiral shape, the protective layer It is possible to obtain an excellent effect in which cracks are hardly generated and the inorganic filler is not easily removed.

Further, in the present invention, when synthesizing the polymer, (meth) acrylonitrile (acrylonitrile and methacrylonitrile) is not used as a raw material, so that the worker can work in a safer environment and is healthy. Damage is less likely to occur.

Furthermore, in the present invention, since the Tg of the polymer is −60 ° C. to 60 ° C., the electrolyte solution resistance of the binder for non-aqueous secondary battery (resin composition for non-aqueous secondary battery) is improved, and the electrode and separator Adhesiveness with (especially polyolefin layer) improves. The Tg of the polymer may be −60 ° C. to 60 ° C., preferably −45 ° C. to 45 ° C., more preferably −30 ° C. to 30 ° C. Tg can be measured using DSC (differential scanning calorimeter, manufactured by TA Instruments). Specifically, about 2 mg of a sample is weighed on an aluminum pan, the aluminum pan is set on a DSC measurement holder, and an endothermic peak obtained under a temperature rising condition of 5 ° C./min is read to measure Tg. be able to.

Hereinafter, the first to third monomers used for the synthesis of such a polymer will be described in detail.

The first monomer contains an acidic functional group. As this acidic functional group, a carboxyl group, a sulfonic acid group, a phosphoric acid group and the like are preferable. By having these acidic functional groups, in addition to improving adhesion to the electrode and the separator (particularly, the polyolefin layer), stability during polymerization is improved. Furthermore, the solution stability of the resin composition for non-aqueous secondary batteries is improved.

Examples of the first monomer containing a carboxyl group include acrylic acid, methacrylic acid, itaconic acid, maleic acid, 2-methacryloylpropionic acid and the like.

Examples of the first monomer containing a sulfonic acid group include styrene sulfonic acid, sodium styrene sulfonate, ammonium styrene sulfonate, 2-acrylamido 2-methylpropane sulfonic acid, sodium 2-acrylamido 2-methylpropanoate, Ryl sulfonic acid, sodium methallyl sulfonate, ammonium methallyl sulfonate, allyl sulfonic acid, sodium allyl sulfonate, ammonium allyl sulfonate, vinyl sulfonic acid, sodium vinyl sulfonate, ammonium vinyl sulfonate, allyloxybenzene sulfonic acid, Examples include sodium allyloxybenzene sulfonate and ammonium allyloxybenzene sulfonate.

Examples of the first monomer containing a phosphoric acid group include 2-methacryloyloxyethyl acid phosphate, 2-acryloyloxyethyl acid phosphate, diphenyl-2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, dibutyl -2-acryloyloxyethyl phosphate, polypropylene glycol monomethacrylate acid phosphate, (2-hydroxyethyl) methacrylate acid phosphate, and the like.

The second monomer contains an amide group but preferably does not contain an acidic functional group. Thereby, it is possible to prevent the action of the amide group from being weakened by the adjacent acidic functional group, and the effect due to the presence of the amide group may be further enhanced. That is, the polymer particles containing the second monomer may have improved resistance to the electrolytic solution depending on the type of the electrolytic solution, and may further improve the affinity with the inorganic filler depending on the type of the inorganic filler. is there. For this reason, the solution stability of the resin composition for non-aqueous secondary batteries containing these may increase more. In addition, as an acidic functional group, the acidic functional group similar to what was described with the 1st monomer mentioned above is mentioned, for example.

Examples of such second monomer include acrylamide, methacrylamide, diacetone acrylamide, N-methyl acrylamide, N-methyl methacrylamide, N-dimethyl acrylamide, N-ethyl acrylamide, N-diethyl acrylamide, N-isopropyl. Examples include acrylamide, N-butylacrylamide, and hydroxyethylacrylamide.

The third monomer is a monomer different from the first monomer, the second monomer, and (meth) acrylonitrile. As the third monomer, various monomers can be used. Specifically, (meth) acrylic acid alkyl ester, hydroxyl group-containing monomer, glycidyl group-containing monomer, polyoxyalkylene group-containing monomer, crosslinkable monomer (Monomers having two or more vinyl groups), alkoxysilyl group-containing monomers, and vinyl monomers (monomers having one vinyl group) are preferred. Among these, the third monomer may contain (meth) acrylic acid alkyl ester as a main component (essential component) and include at least one of a polyoxyalkylene group-containing monomer, a crosslinkable monomer, and an alkoxysilyl group-containing monomer. preferable.

Each of the first to third monomers can be used alone or in combination of two or more.

Examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, tertiary butyl (meth) acrylate, pentyl (meth) acrylate, Hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undel (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, Tetradecyl (meth) acrylate, hexadecyl (meth) acrylate, octadecyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, benzyl Meth) acrylate.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, glycerol mono (meth) acrylate, allyl alcohol, and the like.

When a hydroxyl group-containing monomer is used, the internal cross-linking of the polymer particles is promoted, so that the cohesive force is increased, and the electrolytic solution resistance and the adhesion with the electrode and the separator (particularly, the polyolefin layer) are further improved.

Examples of the glycidyl group-containing monomer include glycidyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate glycidyl ether.

When the glycidyl group-containing monomer is used, the internal crosslinking of the polymer particles is promoted, so that the cohesive force is increased, and the resistance to the electrolyte and the adhesion to the electrode and the separator (particularly, the polyolefin layer) are further improved.

Examples of the polyoxyalkylene group-containing monomer include diethylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, polyethylene glycol / polypropylene glycol mono (meth) acrylate, methoxydiethylene glycol mono (meth) acrylate, methoxypolyethylene glycol mono ( Examples include meth) acrylate, phenoxydiethylene glycol mono (meth) acrylate, and phenoxypolyethylene glycol mono (meth) acrylate.

When a polyoxyalkylene group-containing monomer is used, the ionic conductivity of the protective layer is further improved, so that battery performance is further improved. In particular, when methoxypolyethylene glycol mono (meth) acrylate is used, such an effect becomes more remarkable. The compounding amount of the polyoxyalkylene group-containing monomer is preferably 0.01 to 5% by weight, more preferably 0.05 to 3% by weight with respect to 100% by weight of the monomer mixture. Thereby, the above effect is further improved.

Examples of crosslinkable monomers include allyl (meth) acrylate, vinyl (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, neopentyl Glycol di (meth) acrylate, glycerin di (meth) acrylate, dimethylol tricyclodecane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate Over DOO, pentaerythritol tetra (meth) acrylate, divinylbenzene, divinyl adipate, diallyl isophthalate, diallyl phthalate, and diallyl maleate and the like.

When a crosslinkable monomer is used, the internal crosslinking of the polymer particles is promoted, so that the cohesive force is increased and the electrolyte resistance is further improved. In particular, when diallyl phthalate is used, such an effect becomes more remarkable. The blending amount of the crosslinkable monomer is preferably 0.01 to 5% by weight and more preferably 0.05 to 3% by weight with respect to 100% by weight of the monomer mixture. Thereby, the above effect is further improved.

Examples of the alkoxysilyl group-containing monomer include γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyltributoxysilane, γ-methacryloxypropylmethyldimethoxysilane, and γ-methacryloxy. Propylmethyldiethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-acryloxypropyltriethoxysilane, γ-acryloxypropyltributoxysilane, γ-acryloxypropylmethyldimethoxysilane, γ-acryloxypropylmethyldiethoxy Silane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltributoxysilane, vinylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, para And styryltrimethoxysilane.

When an alkoxysilyl group-containing monomer is used, the internal crosslinking of the polymer particles is promoted, so that the cohesive force is increased and the electrolyte resistance is further improved. In particular, when γ-methacryloxypropyltrimethoxysilane is used, such an effect becomes more remarkable. The compounding amount of the alkoxysilyl group-containing monomer is preferably 0.01 to 5% by weight, more preferably 0.05 to 3% by weight, based on 100% by weight of the monomer mixture. Thereby, the above effect is further improved. Further, among the third monomers, the alkoxysilyl group-containing monomer is more preferable because it can improve the cohesion with a small amount, and can achieve both a high level of electrolytic solution resistance and adhesion.

Examples of vinyl monomers include styrene, α-methylstyrene, vinyl acetate and the like. When a vinyl monomer is used, it becomes easy to adjust the hardness etc. of a protective layer according to an embodiment. The amount of the vinyl monomer used is preferably 0.1 to 50% by weight, for example, 0.1 to 30% by weight with respect to 100% by weight of the total of the first to third monomers (monomer mixture). More preferred is 0.1 to 10% by weight. Thereby, the above effect is further improved.

By copolymerizing the above monomers at a predetermined ratio (blending ratio), a polymer (binder for non-aqueous secondary battery) with further improved electrolyte resistance can be obtained. Specifically, the proportions of the first to third monomers used for copolymerization are 0.1 to 5% by weight for the first monomer and 0.1% for the second monomer with respect to 100% by weight of the monomer mixture. It is preferred that 1-5% by weight and the third monomer is 90-99.8% by weight.

Further, a resin for a non-aqueous secondary battery obtained by mixing an inorganic filler with a polymer (a binder for a non-aqueous secondary battery) obtained by copolymerizing the first to third monomers at these ratios (blending ratio). The composition further improves its electrolyte resistance and solution stability.

Such copolymerization of the monomer is preferably performed in the presence of at least one of a surfactant and a protective colloid.

The ionic species of the surfactant includes anions, cations and nonions, with anions and nonions being preferred. As the surfactant, a reactive surfactant having at least one unsaturated double bond (vinyl group, (meth) acryloyl group) capable of radical polymerization in the molecule can also be used.

As the non-reactive surfactant, the anionic surfactant preferably has a main skeleton of sulfosuccinate, alkyl ether, alkylphenyl ether, alkylphenyl ester, (meth) acrylate sulfate, or phosphate.

Specific examples of anionic surfactants include higher fatty acid salts such as sodium oleate, alkylaryl sulfonates such as dodecylbenzene sulfonic acid, alkyl sulfate esters such as sodium lauryl sulfate, polyoxyethylene lauryl ether sodium sulfate, etc. Polyoxyethylene alkyl ether sulfates, sodium monooctylsulfosuccinate, sodium dioctylsulfosuccinate, polyoxyethylene lauryl sodium sulfosuccinate and derivatives thereof, polyoxyethylene distyrenated phenyl ether sulfate Etc.

As the non-reactive surfactant, the nonionic surfactant is preferably an alkyl ether, an alkylphenyl ether, or an alkylphenyl ester as a main skeleton.

Specific examples of nonionic surfactants include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether, polyoxyethylene alkylphenyls such as polyoxyethylene octylphenyl ether and polyoxyethylene nonylphenyl ether. Sorbitan higher fatty acid esters such as ether, sorbitan monolaurate, sorbitan monostearate, sorbitan trioleate, polyoxyethylene sorbitan higher fatty acid esters such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monostearate, polyoxyethylene Polyoxyethylene higher fatty acid esters such as monolaurate and polyoxyethylene monostearate, oleic acid Noguriseraido, glycerin higher fatty acid esters such as stearic acid monoglyceride, polyoxyethylene polyoxypropylene block copolymers, polyoxyethylene distyrenated phenyl ether and the like.

The surfactant can be used as a non-reactive surfactant, but is preferably used as a reactive surfactant. Here, the reactive surfactant is a surfactant having at least one unsaturated double bond (vinyl group, (meth) acryloyl group) capable of radical polymerization in the molecule. As these reactive surfactants, compounds in which an unsaturated double bond capable of radical polymerization is bonded to the above-described surfactant (preferably anionic surfactant or nonionic surfactant) can be used. .

The surfactant is preferably used in an amount of 0.1 to 5 parts by weight with respect to 100 parts by weight of the monomer mixture.

The copolymerization of the monomer can also be performed in the presence of a radical polymerization initiator (hereinafter referred to as “polymerization initiator”). As the polymerization initiator, known oil-soluble polymerization initiators and water-soluble polymerization initiators can be used, but it is preferable to use water-soluble polymerization initiators.

Examples of the oil-soluble polymerization initiator include benzoyl peroxide, tertiary butyloxybenzoate, tertiary butyl hydroperoxide, tertiary butyl peroxy-2-ethylhexanoate, tertiary butyl peroxy-3,5, 5, organic peroxides such as trimethylhexanoate, ditertiary butyl peroxide, cumene hydroperoxide, p-menthane hydroperoxide, 2,2'-azobisisobutyronitrile, 2,2'-azobis- Examples include azobis compounds such as 2,4-dimethylvaleronitrile, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 1,1′-azobis-cyclohexane-1-carbonitrile.

Examples of the water-soluble polymerization initiator include ammonium persulfate, sodium persulfate, potassium persulfate, hydrogen peroxide, 2,2'-azobis (2-methylpropionamidine) dihydrochloride, and the like.

Note that 0.03 to 5 parts by weight of such a polymerization initiator is preferably used with respect to 100 parts by weight of the monomer mixture.

In the copolymerization, a reducing agent can be used in combination with a polymerization initiator. Thereby, the polymerization reaction can be promoted.

Such reducing agents include reducing organic compounds such as metal salts such as ascorbic acid, erythorbic acid, tartaric acid, citric acid, glucose, formaldehyde sulfoxylate, sodium sulfite, sodium bisulfite, sodium metabisulfite (SMBS) And reducing inorganic compounds such as sodium hyposulfite, ferrous chloride, Rongalite and the like. The reducing agent is preferably used in an amount of 0.01 to 2.5 parts by weight with respect to 100 parts by weight of the monomer mixture.

Also, when copolymerizing monomers, a buffer, a chain transfer agent, a basic compound, etc. can be used as necessary.

Examples of the buffer include sodium acetate, sodium citrate, and sodium bicarbonate.

Examples of the chain transfer agent include octyl mercaptan, tertiary decyl mercaptan, lauryl mercaptan, stearyl mercaptan, 2-ethylhexyl mercaptoacetate, octyl mercaptoacetate, 2-ethylhexyl mercaptopropionate, octyl mercaptopropionate, and the like.

Basic compounds are compounds used for neutralization. Examples of the basic compound include alkylamines such as trimethylamine, triethylamine, and butylamine, alcohol amines such as 2-dimethylaminoethanol, diethylaminoethanol, diethanolamine, triethanolamine, and aminomethylpropanol, morpholine, and ammonia.

The average particle diameter of the polymer particles is preferably 50 to 500 nm, more preferably 100 to 300 nm. By using polymer particles having an average particle diameter of 50 to 500 nm, the adhesion between the protective layer and the electrode and separator (particularly, the polyolefin layer) is further improved. Furthermore, the solution stability of the resin composition for non-aqueous secondary batteries obtained by mixing such polymer particles (binder for non-aqueous secondary batteries) and an inorganic filler is further improved. In addition, an average particle diameter is D50 average particle diameter which used the dynamic light scattering measuring method. The measurement can be performed with Nanotrac (manufactured by Nikkiso Co., Ltd.) by preparing a diluted solution obtained by diluting an aqueous dispersion of polymer particles 500 times with water and using about 5 mL of the diluted solution.

The resin composition for non-aqueous secondary batteries of the present invention preferably contains a binder (polymer particles) for non-aqueous secondary batteries and an inorganic filler. It is preferable that the said inorganic filler is comprised with the inorganic compound which does not change in the electrolyte solution of a non-aqueous secondary battery. Specific examples of the inorganic compound include aluminum oxide, zirconium oxide, titanium oxide, silica, and ion conductive glass.

The average particle size of the inorganic filler is preferably 0.01 to 10 μm. By using the inorganic filler having the average particle diameter, the protective layer can achieve both higher coating strength and lithium ion conductivity.

The polymer particles are preferably used in an amount of 0.1 to 10 parts by weight, more preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the inorganic filler. By using 0.1 to 10 parts by weight of polymer particles with respect to 100 parts by weight of the inorganic filler, the adhesion between the inorganic fillers and the excellent adhesion and flexibility to the electrode and separator of the protective layer can be achieved. While maintaining, the lithium ion conductivity of the protective layer can be further improved.

In the resin composition for a non-aqueous secondary battery of the present invention, it is preferable to add a leveling agent, a dispersant, a thickener, an antifoaming agent, etc. as other optional components. Examples of the leveling agent include silicon, fluorine, metal, and succinic acid. Examples of the dispersant include an anionic compound, a nonionic compound, and a polymer compound.

As the solvent used in the resin composition for a non-aqueous secondary battery of the present invention, water is preferably used, but a water-soluble solvent can also be used as necessary. Examples of the water-soluble solvent include alcohol, glycol, cellosolve, amino alcohol, amine, ketones, carboxylic acid amide, phosphoric acid amide, sulfoxide, carboxylic acid ester, phosphoric acid ester, ether, and nitrile.

The production of the resin composition for a non-aqueous secondary battery of the present invention can be performed using a known mixing device. Specific examples of the mixing apparatus include a disper, a homomixer, a planetary mixer, a ball mill, a sand mill, an attritor, a pearl mill, a jet mill, and a roll mill.

Next, the nonaqueous secondary battery of the present invention will be described by taking LIB as an example. The LIB includes at least a battery body including a positive electrode, a negative electrode, and a separator provided between the positive electrode and the negative electrode, and an electrolyte solution impregnated in the battery body. FIG. 1 is a longitudinal sectional view showing an embodiment of a LIB. The LIB 100 shown in FIG. 1 is a button-type non-aqueous secondary battery having a disk shape as a whole. The LIB 100 includes a battery container 10, a battery main body 1 accommodated in the battery container 10, and an electrolyte solution filled (supplied) in the battery container 10.

The battery container 10 includes a positive electrode case 11, a negative electrode case 12, and a sealing material 13 that seals between the positive electrode case 11 and the negative electrode case 12 in a liquid-tight manner. The battery body 1 is housed in a space defined by the positive electrode case 11, the negative electrode case 12 and the sealing material 13. The battery body 1 is in contact with the positive electrode case 11 and the negative electrode case 12 while being housed in the battery container 10.

The battery body 1 includes a positive electrode 2 and a negative electrode 3 (hereinafter, collectively referred to as “electrode”), and a separator 4 provided between the positive electrode 2 and the negative electrode 3. The battery body 1 is housed in the battery container 10 and the electrolyte solution is loaded (impregnated) in the battery body 1 (separator 4) by filling (supplying) the electrolyte in the space in the battery container 10. .

The positive electrode 2 and the negative electrode 3 were formed using

current collectors

21 and 31 and a composite composition provided on the separator 4 side of the

current collectors

21 and 31 and including an electrode active material as an essential component. The composite material layers 22 and 32 are included. As shown in FIG. 1, the resin composition for a non-aqueous secondary battery of the present invention is further used for the positive electrode 2 and the negative electrode 3 on the surface opposite to the

current collectors

21 and 31 of the composite material layers 22 and 32. Thus, the protective layer 5 is formed. With this protective layer 5, when lithium dendrite-like particles are produced, a short circuit occurs between the two electrodes, and the risk of explosion of the nonaqueous secondary battery can be reduced. The positive electrode 2 and the negative electrode 3 on which the protective layer 5 is formed constitute the non-aqueous secondary battery electrode (electrode with protective layer) of the present invention.

Although it does not specifically limit as a positive electrode active material, Metal compounds, such as a metal oxide and metal sulfide which can dope or intercalate lithium ion, a conductive polymer, etc. can be used. Examples of the metal oxide or metal compound include oxides of transition metals such as Fe, Co, Ni, and Mn, complex oxides with lithium, and inorganic compounds such as transition metal sulfides. Specific examples of the metal oxide or metal compound include transition metal oxide powders such as MnO, V ₂ O ₅ , V ₆ O ₁₃ , TiO ₂ , layered lithium nickelate, lithium cobaltate, lithium manganate, spinel. Examples thereof include composite oxide powders of lithium and transition metals such as lithium manganate having a structure, lithium iron phosphate materials which are lithium acid compounds having an olivine structure, and transition metal sulfide powders such as TiS ₂ and FeS. In addition, these can be used 1 type or in combination of 2 or more types.

The negative electrode active material is not particularly limited as long as it can be doped or intercalated with lithium ions. Examples of the negative electrode active material include metal Li, alloys containing metal Li (for example, tin alloy, silicon alloy, lead alloy), metal oxides such as lithium titanate, lithium vanadate, lithium siliconate, polyacetylene, poly- Conductive polymer such as p-phenylene, soft carbon, amorphous carbon material of hard carbon, artificial graphite such as highly graphitized carbon material, carbonaceous powder such as natural graphite, carbon black, mesophase carbon black, resin-fired carbon material And carbon materials such as vapor-grown carbon fiber and carbon fiber. In addition, these can be used 1 type or in combination of 2 or more types.

As the

current collectors

21 and 31, current collectors applicable to various secondary batteries can be appropriately selected. Examples of the material of the

current collectors

21 and 31 include metals such as aluminum, copper, nickel, titanium, and stainless steel, alloys thereof, and the like. In the case of LIB, it is preferable to use a current collector 21 made of aluminum for the positive electrode 2 and a current collector 31 made of copper for the negative electrode 3. The thickness of the

current collectors

21 and 31 is preferably 5 to 50 μm.

The method for forming the

composite layers

22 and 32 and the protective layer 5 is preferably coating. Specific examples of the coating method include die coating method, dip coating method, roll coating method, doctor coating method, knife coating method, spray coating method, gravure coating method, screen printing method, electrostatic coating method and the like. It is also preferable to dry the solvent during coating. Specifically, known drying methods such as hot air drying, infrared drying, and far infrared radiation can be used.

The thickness of the composite material layers 22 and 32 is preferably 30 to 300 μm.

The protective layer 5 formed from the resin composition for non-aqueous secondary batteries of the present invention is provided on the surface of the mixture layers 22 and 32 opposite to the

current collectors

21 and 31.

The thickness of the protective layer 5 is preferably 0.5 to 50 μm, more preferably 1 to 30 μm. By setting the thickness of the protective layer 5 to 0.5 to 50 μm, the protective layer 5 ensures sufficient strength as a film and obtains an electrode (non-aqueous secondary battery) that exhibits excellent battery performance. Can do.

A separator 4 is provided between the positive electrode 2 with a protective layer and the negative electrode 3 with a protective layer as described above. The separator 4 is a porous sheet or non-woven fabric having fine pores through which ions can pass. Specifically, the separator 4 can be configured using a known material such as polyolefin such as polyethylene or polypropylene, cellulose, or aromatic polyamide.

As shown in FIG. 1, protective layers 5 are formed on both sides of the separator 4. This protective layer 5 improves the heat resistance of the separator 4, and when the non-aqueous secondary battery is overheated, a short circuit occurs between the two electrodes, thereby reducing the risk of the non-aqueous secondary battery exploding. it can. The protective layer 5 is preferably formed on both sides of the separator 4, but may be on one side. When the protective layer 5 is formed on one side of the separator 4, it is preferable to dispose the separator 4 with the protective layer 5 facing the negative electrode 3 side on which dendritic particles tend to be preferentially generated.

The protective layer 5 can be formed in the same manner as the protective layer 5 described in the above electrode, and can have the same thickness. In the present invention, the protective layer 5 has particularly good adhesion to the separator 4 using a polyolefin sheet that is generally difficult to adhere. In addition, a sheet, a film, and a layer have the same meaning content.

The separator 4 on which the protective layer 5 is formed constitutes the nonaqueous secondary battery separator (separator with protective layer) of the present invention.

Further, as shown in an enlarged view in FIG. 1, the protective layer 5 of the present embodiment includes a resin composition for a non-aqueous secondary battery including polymer particles 51 (a binder for a non-aqueous secondary battery) and an inorganic filler 52. It is formed of things. The polymer particles 51 are point-bonded to the inorganic fillers 52. Thereby, a sufficiently large gap can be secured between the inorganic fillers 52. For this reason, the protective layer 5 has excellent ionic conductivity. As a result, the battery characteristics of the LIB 100 including the protective layer 5 are further improved.

The separator 4 is impregnated (held) with an electrolytic solution. This electrolytic solution is a liquid in which an electrolyte containing lithium is dissolved in a non-aqueous solvent. Specific examples of the electrolyte, for _{_{example, LiBF 4, LiClO 4, LiPF}} 6, LiAsF 6, LiSbF 6, LiCF 3 SO 3, Li (CF 3 SO 2) 2 N, LiC 4 F 9 SO 3, Li (CF 3 _{_{SO 2) 3 C, LiI,}} LiBr, LiCl, LiAlCl, LiHF 2, LiSCN, LiBPh 4 , and the like.

Examples of the non-aqueous solvent include carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate, and lactones such as γ-butyl lactone, γ-valerolactone, and γ-octanoic lactone. , Tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 1,2-methoxyethane, 1,2-ethoxyethane, 1,2-dibutoxyethane and the like, methyl Examples thereof include esters such as formate, methyl acetate and methyl propionate, sulfoxides such as dimethyl sulfoxide and sulfolane, and nitriles such as acetonitrile. These can be used alone or in combination of two or more.

It is also preferable to use the electrolytic solution as a polymer electrolyte that is gelled by being held in a polymer matrix. Specific examples of the material for the polymer matrix include an acrylic resin having a polyalkylene oxide segment, a polyphosphazene resin having a polyalkylene oxide segment, and a polysiloxane resin having a polyalkylene oxide segment.

In this embodiment, the button-type LIB has been described as the non-aqueous secondary battery. However, the non-aqueous secondary battery of the present invention is not limited to this, and may be a cylindrical type, a square type, a coin type, a pack type, a sheet type, or the like. For example, when the non-aqueous secondary battery is a cylindrical shape, a rectangular shape or the like, the battery body 1 may be wound into a cylindrical shape or a rectangular tube shape and stored in the battery container 10. As described above, the inorganic filler 52 has good affinity with the polymer particles 51 and is uniformly dispersed in the resin composition for non-aqueous secondary batteries. For this reason, even when the battery body 1 is wound into a cylindrical shape or a rectangular tube shape, the protective layer 5 is not easily cracked, and the inorganic filler 52 is not easily detached from the protective layer 5.

The non-aqueous secondary battery using the above members is excellent in safety and battery characteristics. The nonaqueous secondary battery of the present invention can be used for industrial use, in-vehicle use, and mobile use.

As described above, the binder for a non-aqueous secondary battery, the resin composition for a non-aqueous secondary battery, the non-aqueous secondary battery separator, the non-aqueous secondary battery electrode and the non-aqueous secondary battery of the present invention are based on the preferred embodiments. explained. However, the present invention is not limited to this. Each component can be replaced with any component that can exhibit the same function, or can be added with any component.

For example, as shown in FIG. 1, the protective layer 5 may be provided on all of the positive electrode 2, the negative electrode 3, and the separator 4, or may be provided on only one of them. Further, the protective layer 5 may be provided in direct contact with the electrode and the separator 4, but between the protective layer 5 and the electrode or separator 4, an arbitrary purpose (for example, improvement in adhesion, smoothness) One or more layers may be provided in order to improve the property.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. In addition, a part means a weight part and% means weight%, respectively.

<Synthesis Example 1> Synthesis of Binder 1.5% of acrylic acid as the first monomer, 2.5% of methacrylamide as the second monomer, 44% of methyl methacrylate, 50% of butyl acrylate as the third monomer, and Mixing 100 parts of a monomer mixture containing 2% diallyl phthalate with 1.5 parts of Eleminol CLS-20 (manufactured by Sanyo Chemical Industries) as an anionic surfactant and 53.1 parts of ion-exchanged water A monomer liquid emulsion was prepared by emulsifying this liquid mixture and then charged into a dropping tank.

Separately, a 2 L four-necked flask equipped with a reflux condenser, a stirrer, a thermometer, a nitrogen inlet tube, and a raw material inlet was prepared as a reaction vessel, and 89.4 parts of ion-exchanged water was charged into the reaction vessel. . Next, nitrogen was introduced into the reaction vessel, and the solution was heated to 60 ° C. while stirring the ion exchange water. Then, 0.2 part of Eleminol CLS-20, which is an anionic surfactant, was added to the reaction vessel, and the monomer pre-emulsion was continuously dropped over 5 hours from the dropping tank. Subsequently, emulsion polymerization was continued for 3 hours by using 0.3 part of ammonium persulfate while maintaining the liquid temperature at about 60 ° C. Thereafter, the solution in the reaction vessel was cooled to 50 ° C., and this solution was filtered through a 180 mesh polyester filter cloth to obtain a binder dispersion. There was no aggregate remaining on the filter cloth, and the polymerization stability was good. The obtained binder dispersion had a nonvolatile content of 40% and an acid value of 13 mgKOH / g.

<Electrolyte resistance of binder>
The obtained binder dispersion was poured into a mold set so that the thickness after drying was 500 μm, and dried at 40 ° C. for 72 hours to prepare a resin film. The obtained resin film was cut into a size of 10 mm long × 10 mm wide to prepare a sample. The sample was immersed in an electrolytic solution at 80 ° C. for 24 hours. Thereafter, the electrolyte solution was washed away with diethyl carbonate at room temperature, and the sample weight after drying at 150 ° C. for 30 minutes was measured to obtain the sample weight after immersion. And the weight reduction rate was calculated on the basis of the sample weight before immersion, and the electrolyte solution tolerance of the binder was evaluated.

As the electrolytic solution, a solution obtained by dissolving LiPF ₆ at a concentration of 1 mol / L in a mixed solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 1: 1 was used.

<Synthesis Examples 2 to 18> Synthesis of Binder Synthesis was performed in the same manner as in Synthesis Example 1 except that the blending composition shown in Table 1 was changed, so that binder dispersions of Synthesis Examples 2 to 18 were obtained.

The abbreviations in the table are as follows.
AA: Acrylic acid MAA: Methacrylic acid NaSS: Sodium styrenesulfonate P-1A (N): 2-acryloyloxyethyl acid phosphate AAm: Acrylamide MAAm: Methacrylamide amide DMAAm: N-dimethylacrylamide MMA: Methyl methacrylate BA: Butyl acrylate 2EHA : 2-ethylhexyl acrylate LMA: dodecyl methacrylate 2HEMA: 2-hydroxyethyl methacrylate GMA: glycidyl methacrylate DAP: diallyl phthalate MOEMA: methoxypolyethylene glycol methacrylate having a molecular weight of about 200 γMPMS: γ-methacryloxypropyltrimethoxysilane St: styrene PAASA: Polyoxyethylene-1- (allyloxymethyl) alkyl ether sulfuric acid Ammonium (reactive anionic surfactant)

<Formulation Example 1> Preparation of Resin Composition for Nonaqueous Secondary Battery Inorganic particles (alumina, volume average particle diameter 0.5 μm) and the binder dispersion obtained in Synthesis Example 1 are in a non-volatile content ratio of 100: 3. It mixed so that it might become. Further, water, a polymer type dispersant, and a leveling agent were added to the binder dispersion containing the inorganic particles, and the mixture was prepared so that the non-volatile content was 20%. . Next, this mixed solution was put into a bead mill and dispersed to obtain a resin composition for a non-aqueous secondary battery.

<Formulation Examples 2 to 18> Preparation of Resin Composition for Nonaqueous Secondary Battery By preparing in the same manner as Formulation Example 1 except that the binder dispersion obtained in Synthesis Examples 2 to 18 was used, Resin compositions for nonaqueous secondary batteries of Examples 2 to 18 were obtained.

<Solution stability>
The obtained resin composition for non-aqueous secondary batteries was stored at 25 ° C., and the stability of the solution was evaluated according to the following evaluation criteria by visually observing the presence / absence of aggregation, sedimentation and separation.
A: No abnormality was observed in the resin composition for nonaqueous secondary batteries for 2 weeks or more after the start of storage. (Especially excellent)
B: Some abnormality was observed in the resin composition for a non-aqueous secondary battery between one week and two weeks from the start of storage. (Practical problem-free level)
C: Some abnormality was observed in the resin composition for nonaqueous secondary batteries within one week from the start of storage. (Usage prohibited)

[Example 1]
<Preparation of positive electrode with protective layer>
5 parts of acetylene black (Denka Black HS-100) as a carbon material, 100 parts of LiFePO ₄ as a positive electrode active material, 1 part of carboxymethylcellulose as a dispersant, and polytetrafluoroethylene 30-J (Mitsui / Dupont Fluoro) as a binder (Chemical Co., 60% water dispersion) 8 parts and water 60 parts were mixed with a planetary mixer to prepare a positive electrode mixture composition.

Then, the obtained positive electrode mixture composition was applied onto an aluminum foil (thickness 20 μm) as a current collector so that the thickness after drying was 80 μm using a doctor blade. Then, heat drying was performed under reduced pressure, and further a rolling process by a roll press was performed to produce a 65 μm-thick composite material layer to obtain a positive electrode.

Next, the protective layer was formed by applying the resin composition for non-aqueous secondary batteries of Formulation Example 1 on the mixture layer of the positive electrode using a doctor blade so that the thickness after drying was 5 μm. Then, the positive electrode with a protective layer (positive electrode for LIB) was produced by heat-drying under pressure reduction.

<Flexibility of protective layer>
The flexibility of the protective layer was evaluated by the following method. The obtained positive electrode with a protective layer was cut into a size of width 10 mm × length 50 mm to prepare a sample. The sample was wound around a metal rod having a diameter of 1.5 mm so that the current collector was in contact. In this state, the surface state of the protective layer was visually observed, and the flexibility was evaluated according to the following evaluation criteria.
A: No change was observed on the surface of the protective layer. (Especially excellent)
B: A change was observed in a part of the surface of the protective layer. (Practical problem-free level)
C: Cracks were observed on a part of the surface of the protective layer. (Usage prohibited)
D: Cracks were observed on the entire surface of the protective layer. (Usage prohibited)

<Adhesiveness of protective layer>
With respect to the obtained positive electrode with a protective layer, notches having a depth reaching the composite layer from the surface of the protective layer using a knife were formed in a grid pattern of 6 in the longitudinal direction and the lateral direction at intervals of 2 mm. As a result, 25 small regions partitioned by a plurality of cuts were formed in the protective layer. A cellophane tape was applied to the portion of the protective layer in which the 25 small regions were formed, and then immediately peeled off from the protective layer. And the presence or absence of peeling from the composite material layer of a small area | region was observed visually, and it evaluated in accordance with the following evaluation criteria.
A: There was no peeling from the small area mixture layer. (Especially excellent)
B: 1 to 15 small regions were peeled from the composite material layer. (Practical problem-free level)
C: 16 or more small regions were peeled from the composite material layer. (Usage prohibited)

<Electrolyte resistance of protective layer>
The obtained positive electrode with a protective layer was cut into a size of 10 mm long × 10 mm wide to prepare a sample. The sample was immersed in an electrolytic solution at 80 ° C. for 24 hours. Thereafter, the electrolyte solution was washed away with diethyl carbonate at room temperature, and the sample weight after drying at 150 ° C. for 30 minutes was measured to obtain the sample weight after immersion. And the weight reduction | decrease rate was calculated on the basis of the sample weight before immersion, and the electrolyte solution tolerance of the protective layer was evaluated according to the following evaluation criteria.
A: Weight reduction rate is less than 1% (particularly excellent)
B: The weight reduction rate is 1% or more and less than 3% (a level causing no problem in practical use)
C: Weight reduction rate is 3% or more (unusable)

<Production of negative electrode>
1 part of acetylene black (Denka Black HS-100) as a carbon material, 100 parts of artificial graphite as a negative electrode active material, 1 part of carboxymethylcellulose as a dispersant, 8 parts of polytetrafluoroethylene 30-J as a binder, and water 70 Were mixed with a planetary mixer to produce a negative electrode mixture composition.

The obtained negative electrode mixture composition was applied onto a copper foil (thickness 20 μm) as a current collector so that the thickness after drying was 80 μm using a doctor blade. Then, it heat-dried under reduced pressure, the 65-micrometer-thick composite material layer was produced by performing the rolling process by a roll press, and the negative electrode (negative electrode for LIB) was produced.

<Assembly of LIB>
The positive electrode with a protective layer was punched into a disk shape having a diameter of 15.9 mm, and the negative electrode was punched into a disk shape having a diameter of 16.1 mm. The separator was formed by punching a porous polypropylene film into a circle having a diameter of 23 mm. The positive electrode with the protective layer and the negative electrode were opposed to each other with the separator interposed between them and housed in a battery container, and a coin-type battery was produced by filling with an electrolyte. The coin-type battery was produced in a glove box substituted with argon.

<Battery characteristics>
The obtained coin-type battery was subjected to charge / discharge measurement as follows using a charge / discharge device (SM-8 manufactured by Hokuto Denko). The constant current charging was continued up to a charging end voltage of 4.2 V at a charging current of 1.2 mA. After the battery voltage reached 4.2 V, constant current discharge was performed at a discharge current of 1.2 mA until the discharge end voltage of 2.0 V was reached. These charge / discharge cycles are defined as one cycle, and 5 cycles of charge / discharge are repeated, and the discharge capacity at the fifth cycle is defined as the initial discharge capacity. The case where the initial discharge capacity was maintained was set to 100%.

Next, after charging as in the 5th cycle, the coin-type battery was stored in a 60 ° C. constant temperature bath for 100 hours and then discharged at a constant discharge current of 1.2 mA until reaching a final discharge voltage of 2.0V. The discharge capacity maintenance rate was calculated. In addition, it shows that a battery characteristic is so favorable that a maintenance factor is near 100%.
A: Maintenance rate is 95% or more (particularly excellent)
B: Maintenance rate is 85% or more and less than 95% (a level that causes no problem in practical use)
C: Maintenance rate is less than 85% (unusable)

[Examples 2 to 5, 23], [Comparative Examples 1 to 5]
Except having used the resin composition for non-aqueous secondary batteries shown in Table 2, the positive electrode with a protective layer was produced like Example 1 and LIB was assembled, and the coin-type battery was obtained. The obtained positive electrode with a protective layer and coin-type battery were evaluated in the same manner as in Example 1.

[Example 6]
<Preparation of negative electrode with protective layer>
On the composite layer of the negative electrode used in Example 1, the protective layer was applied by applying the nonaqueous secondary battery resin composition of Formulation Example 1 using a doctor blade so that the thickness after drying was 5 μm. After that, a negative electrode with a protective layer (LIB negative electrode) was obtained by heating and drying under reduced pressure.

<Assembly of LIB>
A coin-type battery was obtained in the same manner as in Example 1 except that the produced negative electrode with a protective layer and the positive electrode without a protective layer were used.

The obtained negative electrode with a protective layer and coin-type battery were evaluated in the same manner as in Example 1.

[Examples 7 to 10], [Comparative Examples 6 to 10]
Except having used the resin composition for non-aqueous secondary batteries shown in Table 2, the negative electrode with a protective layer was produced similarly to Example 6, the LIB was assembled, and the coin-type battery was obtained. The obtained negative electrode with protective layer and coin-type battery were evaluated in the same manner as in Example 1.

[Example 11]
<Preparation of separator with protective layer>
On one side of the separator used in Example 1 (surface on the negative electrode side of the separator), the non-aqueous secondary battery resin composition of Formulation Example 1 was applied using a doctor blade so that the thickness after drying was 5 μm. Then, a protective layer was formed, and then heat-dried under reduced pressure to obtain a separator with a protective layer (LIB separator).

<Assembly of LIB>
A coin-type battery was obtained in the same manner as in Example 1 except that the manufactured separator with a protective layer and the positive electrode not forming the protective layer were used. In addition, the separator with a protective layer was installed with the protective layer facing the negative electrode.

Evaluation was performed in the same manner as in Example 1 for the obtained separator with a protective layer and coin-type battery.

[Examples 12 to 22, 24], [Comparative Examples 11 to 15]
Except having used the resin composition for non-aqueous secondary batteries shown in Table 2, it carried out similarly to Example 11, produced the separator with a protective layer, assembled LIB, and obtained the coin-type battery. The obtained separator with a protective layer and coin-type battery were evaluated in the same manner as in Example 1.

As is clear from Table 2, in each Example, good results were obtained for any of the evaluations of solution stability, flexibility, adhesion, electrolyte solution resistance, and battery characteristics. On the other hand, in each comparative example, satisfactory results could not be obtained in the evaluation of characteristics. That is, in each example, there was no result of C or D in the evaluation of five characteristics, whereas in each comparative example, there was at least one result of C or D in the evaluation of five characteristics.

Examples 1 to 4, Examples 6 to 8, Examples 11 to 17 and Examples using polymers (binders) obtained by copolymerizing the first to third monomers at a predetermined ratio (blending ratio) In 23 and Example 24, the evaluation results of the characteristics were particularly good.

Furthermore, by using a polymer (binder) obtained by copolymerizing a third monomer containing methoxypolyethylene glycol methacrylate, diallyl phthalate, and γ-methacryloxypropyltrimethoxysilane, the evaluation results of the characteristics are improved. Tended to be.

The binder for a non-aqueous secondary battery of the present invention includes a plurality of particles composed of a polymer, and the polymer includes a first monomer containing an acidic functional group, a second monomer containing an amide group, The first monomer, the second monomer, and a third monomer different from (meth) acrylonitrile are copolymerized, and the glass transition temperature is −60 ° C. to 60 ° C.

Thereby, it is possible to obtain a protective layer which is excellent in resistance to electrolyte and has good adhesion to the electrode and the separator. Furthermore, the binder for non-aqueous secondary batteries of the present invention is produced without using (meth) acrylonitrile as a raw material. For this reason, the safety | security at the time of manufacturing the binder for non-aqueous secondary batteries improves, and the effect that a health hazard hardly arises is also acquired. Therefore, the present invention has industrial applicability.

Claims

Comprising a plurality of particles composed of a polymer;
The polymer includes a first monomer containing an acidic functional group, a second monomer containing an amide group, a third monomer different from the first monomer, the second monomer, and (meth) acrylonitrile. And a glass transition temperature of -60 ° C to 60 ° C.
The binder for a non-aqueous secondary battery according to claim 1, wherein the second monomer does not contain an acidic functional group.
The polymer comprises 0.1 to 5% by weight of the first monomer and 0.1 to 5% by weight of the second monomer with respect to a total of 100% by weight of the first to third monomers. The binder for a non-aqueous secondary battery according to claim 1, wherein 90% to 99.8% by weight of the third monomer is copolymerized.
2. The non-aqueous secondary battery according to claim 1, wherein the third monomer is essentially a (meth) acrylic acid alkyl ester and includes at least one of a polyoxyalkylene group-containing monomer, a crosslinkable monomer, and an alkoxysilyl group-containing monomer. Binder.
The binder for non-aqueous secondary batteries according to claim 1, wherein the average particle diameter of the particles is 50 to 500 nm.
A resin composition for a non-aqueous secondary battery comprising the binder for a non-aqueous secondary battery according to claim 1 and an inorganic filler.
A non-aqueous two comprising a sheet-like separator and a protective layer provided on at least one surface side of the separator and formed from the resin composition for a non-aqueous secondary battery according to claim 6. Secondary battery separator.
The non-aqueous secondary battery separator according to claim 7, wherein the sheet-like separator is made of polyolefin.
An electrode including a current collector and a composite material layer, provided on the surface of the composite material layer opposite to the current collector, and formed from the resin composition for a non-aqueous secondary battery according to claim 6. A non-aqueous secondary battery electrode comprising a protective layer.
A nonaqueous secondary battery comprising at least one of the nonaqueous secondary battery separator according to claim 7 and the nonaqueous secondary battery electrode according to claim 9.