JP2003045483A - Non-aqueous electrolyte battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-aqueous electrolyte battery having high charging/ discharging efficiency and high energy density. SOLUTION: The non-aqueous electrolyte battery is constituted at least of a positive electrode containing a positive electrode active material as a main component, negative electrode containing a negative active material as the main component, and non-aqueous electrolyte. In this battery, by including in the non-aqueous electrolyte a fluoride or γ-butyrolactone derivatives, the purpose can be accomplished. It is preferable that the negative active material is graphite, and that an exterior body of the battery is a metallic resin composite material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous electrolyte battery, and more particularly to improvement of a non-aqueous electrolyte used in a non-aqueous electrolyte battery.

[0002]

2. Description of the Related Art In recent years, non-aqueous electrolyte batteries, especially lithium secondary batteries, have been used as power sources for mobile devices such as mobile phones, PHS (simple mobile phones), and small computers, power storage power sources,
It is attracting attention as a power source for electric vehicles.

A lithium secondary battery is generally composed of a positive electrode having a positive electrode active material as a main constituent, a negative electrode having a negative electrode active material as a main constituent, and a non-aqueous electrolyte.

A lithium-containing transition metal oxide is used as a positive electrode active material constituting a lithium secondary battery, a carbonaceous material typified by graphite is used as a negative electrode active material, and phosphorus hexafluoride is used as a non-aqueous electrolyte. Lithium acid (LiP
It is widely known that an electrolyte such as F ₆ ) is dissolved in a non-aqueous solvent containing ethylene carbonate as a main constituent.

[0005]

However, since ethylene carbonate has a high melting point, the electrolytic solution easily solidifies at low temperatures. Therefore, in place of ethylene carbonate, a method of using a lower melting point propylene carbonate as a non-aqueous solvent of the electrolytic solution is known, but during charging, especially propylene carbonate decomposes on the graphite negative electrode at the time of initial charging, There was a problem that the battery performance was not sufficiently obtained.

As a means for solving this problem, Japanese Patent Laid-Open No.
Japanese Patent Application Laid-Open No. 1-67266 discloses a technique of applying a non-aqueous solvent containing propylene carbonate and vinylene carbonate for suppressing the above decomposition of propylene carbonate as essential components to a non-aqueous electrolyte battery. That is, by decomposing vinylene carbonate on the graphite negative electrode during initial charging, a lithium ion permeable protective coating is formed on the surface of the graphite negative electrode, so that decomposition of propylene carbonate is suppressed, and high temperature characteristics and high energy density are obtained. It is said that a non-aqueous electrolyte battery having the same can be obtained. However, since vinylene carbonate is inferior in oxidation resistance and decomposes on the positive electrode, adding a large amount thereof causes a problem of deteriorating battery performance.

The present invention has been made in view of the above problems, and an object thereof is to provide a non-aqueous electrolyte battery having high charge / discharge efficiency and high energy density.

[0008]

In order to solve the above-mentioned problems, the present inventors have made earnest studies and as a result, by surprisingly selecting a non-aqueous solvent constituting a non-aqueous electrolyte, surprisingly, The inventors have found that a non-aqueous electrolyte battery having a high charge / discharge efficiency and a high energy density can be obtained, and completed the present invention. That is, the technical configuration of the present invention and its function and effect are as follows. However, the mechanism of action includes estimation, and its correctness does not limit the present invention.

According to a first aspect of the present invention, there is provided a non-aqueous electrolyte battery including at least a positive electrode having a positive electrode active material as a main constituent, a negative electrode having a negative electrode active material as a main constituent, and a non-aqueous electrolyte. The non-aqueous electrolyte contains a fluoride of a γ-butyrolactone derivative, which is a non-aqueous electrolyte battery.

According to the invention of claim 1, since the non-aqueous electrolyte contains the fluoride of the γ-butyrolactone derivative, the fluoride of the γ-butyrolactone derivative is decomposed on the graphite negative electrode at the time of initial charge, and the graphite negative electrode. To form a protective film that is permeable to lithium ions on the surface,
Since the decomposition of the other organic solvent that constitutes the non-aqueous electrolyte can be reliably suppressed, the charging can be sufficiently performed. Moreover, since the fluoride of the γ-butyrolactone derivative is fluorinated, it has a high oxidation resistance, almost no oxidative decomposition occurs on the positive electrode, and the addition thereof in excess does not deteriorate the battery performance. Therefore, a non-aqueous electrolyte battery having high charge / discharge efficiency and high energy density can be obtained.

The invention according to claim 2 is the non-aqueous electrolyte battery, wherein the negative electrode active material is graphite.

According to the second aspect of the present invention, graphite has a metallic lithium potential (in the case of an aqueous solution, −3.045 V).
vs. Since it has an operating potential very close to that of NHE) and can reduce the irreversible capacity during charge and discharge, it is possible to obtain a non-aqueous electrolyte battery having a high operating voltage and a high energy density.

According to a third aspect of the present invention, there is provided a non-aqueous electrolyte battery characterized in that a metal resin composite material is used for an outer casing of the non-aqueous electrolyte battery.

According to the third aspect of the present invention, the metal-resin composite material is lighter than metal and can be easily formed into a thin shape, so that the non-aqueous electrolyte battery can be made compact and lightweight.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The embodiments of the present invention will be illustrated below, but the present invention is not limited to these descriptions.

The non-aqueous electrolyte battery according to the present invention comprises a positive electrode having a positive electrode active material as a main constituent, a negative electrode having a negative electrode active material as a main constituent, and a non-aqueous electrolyte. A non-aqueous electrolyte battery separator is provided between the positive electrode and the negative electrode.

Examples of the fluoride of the γ-butyrolactone derivative include those having the following structures. These may be used alone or in combination of two or more.

[0018]

[Chemical 1]

The content of the fluoride of the γ-butyrolactone derivative is preferably 0.01% by weight to 10% by weight, more preferably 0.10% by weight to 5% by weight based on the total weight of the non-aqueous electrolyte. % By weight. The content of the fluoride of the γ-butyrolactone derivative is 0.01% by weight or more with respect to the total weight of the non-aqueous electrolytic solution, so that decomposition of other organic solvents constituting the non-aqueous electrolytic solution at the time of initial charging Can be suppressed almost completely, and charging can be performed more reliably. Further, when the content is 10% by weight or less, the viscosity of the electrolytic solution does not become too high, so that sufficient battery performance can be exhibited even at the time of high rate charge / discharge and at low temperature.

As the organic solvent constituting the non-aqueous electrolyte, an organic solvent generally used for non-aqueous electrolytes for non-aqueous electrolyte batteries can be used. For example, cyclic carbonate such as propylene carbonate, ethylene carbonate, butylene carbonate, chloroethylene carbonate, vinylene carbonate; cyclic ester such as γ-butyrolactone, γ-valerolactone, propiolactone; dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, Chain carbonates such as diphenyl carbonate; chain esters such as methyl acetate and methyl butyrate; tetrahydrofuran or its derivatives, ethers such as 1,3-dioxane, dimethoxyethane, diethoxyethane, methoxyethoxyethane, methyldiglyme; acetonitrile , Nitriles such as benzonitrile; dioxalane or its derivatives; sulfolane, sultone or its derivatives, etc., or a mixture of two or more thereof. However, the present invention is not limited to these.

In particular, when the fluoride of the γ-butyrolactone derivative used in the present invention is used by adding it to a non-aqueous electrolyte containing propylene carbonate, the characteristics of propylene carbonate having a high dielectric constant can be sufficiently exhibited, and The effect of suppressing decomposition of a solvent such as propylene carbonate on graphite can be extremely effectively exerted, and therefore, it is more preferable in that a battery further excellent in high rate discharge characteristics and low temperature characteristics can be provided.

Examples of the electrolyte salt include LiCl
O_Four, LiBF_Four, LiAsF₆, LiPF₆, LiCF₃
SO₃, LiN (CF₃SO₂)₂, LiN (C₂F_FiveS
O₂)₂, LiSCN, LiBr, LiI, Li₂SO_Four，
Li₂B_TenCl_Ten, NaClO_Four, NaI, NaSCN,
NaBr, KClO_Four, KSCN and other lithium (L
i), one of sodium (Na) or potassium (K)
Inorganic ion salt containing LiN (CF ₃SO₂)₂, LiN
(C₂F_FiveSO₂)₂, (CH₃)_FourNBF_Four, (CH₃)_FourN
Br, (C₂H_Five)_FourNClO_Four, (C₂H_Five)_FourNI, (C₃
H₇)_FourNBr, (n-C_FourH₉) _FourNClO_Four, (N-C_Four
H₉)_FourNI, (C₂H_Five)_FourN-maleate, (C₂H
_Five)_FourN-benzoate, (C₂H_Five)_FourN-phta
Quaternary ammonium salt such as late, stearyl sulfone
Lithium oxide, lithium octyl sulfonate, dodecylbe
Examples include organic ionic salts such as lithium benzenesulfonate.
These ionic compounds may be used alone or in combination of two or more.
It is possible to mix and use the above.

The concentration of the electrolyte salt in the non-aqueous electrolyte is preferably 0.1 mol / l to 5 mol / l in order to reliably obtain a non-aqueous electrolyte battery having high battery characteristics.
More preferably, it is 1 mol / l to 2.5 mol / l.

As the positive electrode active material which is the main constituent of the positive electrode, it is desirable to use lithium-containing transition metal oxides, lithium-containing phosphates, lithium-containing sulfates, etc., alone or in combination. Examples of the lithium-containing transition metal oxide include general formulas Li _y Co _1-x M _x O ₂ and Li _y Mn _2-x M _x.
O ₄ (M is a metal of group I to VIII (for example, Li, C
a, Cr, Ni, Fe, Co, one or more kinds of elements), and the x value showing the substitution amount of different elements is effective up to the maximum substitution amount, but preferably 0 from the viewpoint of discharge capacity.
≦ x ≦ 1. Further, regarding the y value indicating the amount of lithium, the maximum amount that can reversibly use lithium is effective,
From the viewpoint of discharge capacity, 0 ≦ y ≦ 2 is preferable. ), But is not limited thereto.

Further, other positive electrode active material may be mixed with the lithium-containing compound, and as the other positive electrode active material, CuO, Cu ₂ O, Ag ₂ O, CuS, CuSO _{4 and the} like can be used. metal compounds, TiS _2, SiO _2, IV group metal compound of SnO, _{etc., V 2 O 5, V 6} O 1 2, VO x, Nb 2 O 5, Bi
Group V metal compounds such as ₂ O ₃ and Sb ₂ O ₃ , CrO ₃ and Cr ₂ O
Group VI metal compounds such as ₃ , MoO ₃ , MoS ₂ , WO ₃ and SeO ₂ , Group VII metal compounds such as MnO ₂ and Mn ₂ O ₃ , Fe ₂
O ₃ , FeO, Fe ₃ O ₄ , Ni ₂ O ₃ , NiO, CoO ₃ ,
Group VIII metal compounds such as CoO, or general formula Li _x M
X ₂ , Li _x MN _y X ₂ (M and N are metals of groups I to VIII, X
Indicates chalcogen compounds such as oxygen and sulfur. ) And the like, for example, a metal compound such as a lithium-cobalt-based composite oxide or a lithium-manganese-based composite oxide,
Examples include conductive polymer compounds such as disulfide, polypyrrole, polyaniline, polyparaphenylene, polyacetylene, and polyacene materials, and carbonaceous materials having a pseudo-graphite structure, but are not limited thereto.

As the negative electrode active material which is the main constituent of the negative electrode, carbonaceous materials, metal oxides such as tin oxide and silicon oxide, and phosphorus and boron are added to these materials for the purpose of improving the negative electrode characteristics. Examples of the modified material include: Among the carbonaceous materials, graphite is preferable as a negative electrode active material because it has a working potential extremely close to that of metallic lithium and thus can reduce self-discharge when a lithium salt is used as an electrolyte salt and can reduce irreversible capacity during charge and discharge. . Further, in the present invention, since the non-aqueous electrolyte containing the fluoride of the γ-butyrolactone derivative is used, decomposition of other organic solvents constituting the non-aqueous electrolyte on the negative electrode containing graphite as a main component during charging is performed. It can be reliably suppressed, and the above-mentioned advantageous properties of graphite can be surely exhibited.

The analytical results of X-ray diffraction and the like of graphite that can be preferably used are shown below: Lattice plane spacing (d002) 0.333 to 0.350 nanometers Crystallite size La 20 in the a-axis direction La 20 Nanometer C-axis crystallite size Lc 20 nanometer True density 2.00 to 2.25 g / cm3 In addition, graphite, metal oxides such as tin oxide and silicon oxide, phosphorus, boron, amorphous carbon It is also possible to add etc. for modification. In particular, by modifying the surface of graphite by the above method, decomposition of the electrolytic solution can be suppressed and battery characteristics can be improved, which is desirable. Further, lithium metal, lithium-aluminum, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium, and lithium metal-containing alloys such as wood alloys may be used in combination with graphite, and it may be possible to use electricity beforehand. Graphite in which lithium is inserted by being chemically reduced can also be used as the negative electrode active material.

It is also possible to modify at least the surface layer portion of the powder of the positive electrode active material and the powder of the negative electrode active material with a material having good electron conductivity or ion conductivity, or a compound having a hydrophobic group. For example, gold, silver, carbon, nickel, copper and other substances with good electron conductivity, lithium carbonate,
A material having good ion conductivity such as boron glass and a solid electrolyte, or a material having a hydrophobic group such as silicone oil may be applied by applying techniques such as plating, sintering, mechanofusion, vapor deposition, and baking.

The positive electrode active material powder and the negative electrode active material powder preferably have an average particle size of 100 μm or less. In particular, the powder of the positive electrode active material is preferably 10 μm or less for the purpose of improving the high output characteristics of the non-aqueous electrolyte battery. A crusher or a classifier is used to obtain the powder in a predetermined shape. For example, mortar, ball mill, sand mill,
A vibrating ball mill, a planetary ball mill, a jet mill, a counter jet mill, a swirling airflow type jet mill, a sieve or the like is used. Wet grinding in which water or an organic solvent such as hexane coexists may be used during grinding. The classification method is not particularly limited, and a sieve or a wind classifier,
Both dry type and wet type are used as necessary.

The positive electrode active material and the negative electrode active material have been described above in detail. In the positive electrode and the negative electrode, in addition to the active material which is a main constituent, a conductive agent, a binder and a filler are other constituent components. May be included as

The conductive agent is not limited as long as it is an electron conductive material that does not adversely affect the battery performance, but usually,
Natural graphite (scaly graphite, flake graphite, earth graphite, etc.), artificial graphite, carbon black, acetylene black, Ketjen black, carbon whiskers, carbon fiber, metal (copper, nickel, aluminum, silver, gold, etc.) powder, A conductive material such as a metal fiber or a conductive ceramic material may be contained as one kind or a mixture thereof.

Of these, acetylene black is preferable as the conductive agent from the viewpoints of conductivity and coatability. The amount of the conductive agent added is preferably 1% by weight to 50% by weight, and particularly preferably 2% by weight to 30% by weight, based on the total weight of the positive electrode or the negative electrode. These mixing methods are physical mixing, and ideally, they are homogeneous mixing. Therefore, V type mixer, S type mixer, grinding machine, ball mill,
A powder mixer such as a planetary ball mill can be mixed dry or wet.

The binder is usually a thermoplastic resin such as polytetrafluoroethylene, polyvinylidene fluoride, polyethylene or polypropylene, ethylene-propylene diene terpolymer (EPDM), sulfonated EPD.
Polymers having rubber elasticity such as M, styrene-butadiene rubber (SBR) and fluororubber, polysaccharides such as carboxymethyl cellulose and the like can be used as one kind or as a mixture of two or more kinds. In addition, it is desirable that the binder having a functional group that reacts with lithium such as a polysaccharide is deactivated by, for example, methylating. The amount of the binder added is 1 to the total weight of the positive electrode or the negative electrode.
50% by weight is preferable, and 2 to 30% by weight is particularly preferable.

As the filler, any material may be used as long as it does not adversely affect the battery performance. Usually, olefin polymers such as polypropylene and polyethylene, metal oxides such as silicon oxide, titanium oxide, aluminum oxide, magnesium oxide, zirconium oxide, zinc oxide and iron oxide, metal carbonates such as calcium carbonate and magnesium carbonate, glass, Carbon or the like is used. The amount of the filler added is preferably 30% by weight or less with respect to the total weight of the positive electrode or the negative electrode.

For the positive electrode and the negative electrode, the active material, the conductive agent, and the binder are mixed with an organic solvent such as N-methylpyrrolidone and toluene, and the resulting mixed liquid is used as a current collector described in detail below. It is suitably prepared by applying it on the surface and drying it. Regarding the coating method, for example, roller coating such as an applicator roll, screen coating, doctor blade method, spin coating, it is desirable to apply to any shape using a means such as bar coder, but to these It is not limited.

The current collector may be any electron conductor as long as it does not adversely affect the constructed battery. For example, as the current collector for the positive electrode, aluminum, titanium,
In addition to stainless steel, nickel, baked carbon, conductive polymers, conductive glass, etc., the surface of aluminum, copper, etc. is carbon, nickel, titanium, silver, etc. for the purpose of improving adhesion, conductivity, and oxidation resistance. The product treated with can be used. As the negative electrode current collector, in addition to copper, nickel, iron, stainless steel, titanium, aluminum, baked carbon, conductive polymer, conductive glass, Al-Cd alloy, adhesiveness,
For the purpose of improving conductivity and oxidation resistance, a material such as copper whose surface is treated with carbon, nickel, titanium, silver or the like can be used. It is also possible to oxidize the surface of these materials.

With respect to the shape of the current collector, in addition to a foil shape, a film shape, a sheet shape, a net shape, a punched or expanded material, a lath body, a porous body, a foam body, a fiber group forming body, or the like is used. To be There is no particular limitation on the thickness, but 1
Those having a thickness of up to 500 μm are used. Among these current collectors, the positive electrode is an aluminum foil having excellent oxidation resistance, and the negative electrode is a stable copper foil in a reducing field and has excellent electrical conductivity, and an inexpensive copper foil, nickel foil, or iron. Preference is given to using foils and alloy foils containing them.
Further, it is preferable that the foil has a rough surface with a surface roughness of 0.2 μmRa or more, and thereby the adhesion between the positive electrode active material or the negative electrode active material and the current collector becomes excellent. Therefore, it is preferable to use the electrolytic foil because it has such a rough surface. In particular, an electrolytic foil that has been treated with a hook is most preferable.

As the separator for a non-aqueous electrolyte battery, it is preferable to use a microporous membrane or a non-woven fabric having excellent rate characteristics, either alone or in combination. Examples of the material forming the separator for the non-aqueous electrolyte battery include polyolefin resins represented by polyethylene, polypropylene, etc., polyester resins represented by polyethylene terephthalate, polybutylene terephthalate, etc., polyvinylidene fluoride, and vinylidene fluoride-hexa. Fluoropropylene copolymer, vinylidene fluoride-perfluorovinyl ether copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-trifluoroethylene copolymer, vinylidene fluoride-fluoroethylene copolymer, fluorine Vinylidene fluoride-hexafluoroacetone copolymer, vinylidene fluoride-ethylene copolymer, vinylidene fluoride-propylene copolymer, vinylidene fluoride-trifluoropropylene copolymer, vinylidene fluoride - tetrafluoroethylene - hexafluoropropylene copolymer, vinylidene fluoride - ethylene - can be mentioned tetrafluoroethylene copolymer.

The porosity of the separator for non-aqueous electrolyte battery is preferably 98% by volume or less from the viewpoint of strength. From the viewpoint of charge / discharge characteristics, the porosity is preferably 20% by volume or more.

The non-aqueous electrolyte battery separator uses a polymer gel composed of an electrolyte and a polymer such as acrylonitrile, ethylene oxide, propylene oxide, methyl methacrylate, vinyl acetate, vinylpyrrolidone or polyvinylidene fluoride. Good.

Further, the separator for non-aqueous electrolyte battery is
It is desirable to use a polymer gel in combination with the above-mentioned porous membrane, non-woven fabric or the like, since the liquid retaining property of the electrolytic solution is improved. That is, by forming a film in which the surface of the polyethylene microporous membrane and the wall of the micropores are coated with a lyophilic polymer having a thickness of several μm or less, and holding the electrolyte solution in the micropores of the film, The polymer gels.

Examples of the solvophilic polymer include polyvinylidene fluoride, a polymer obtained by crosslinking an acrylate monomer having an ethylene oxide group, an ester group and the like, an epoxy monomer, a monomer having an isocyanate group and the like. For crosslinking, heat and ultraviolet rays (UV)
And actinic rays such as electron beam (EB) can be used.

For the purpose of controlling strength and physical properties, the solvent-philic polymer may be blended with a physical property-adjusting agent within a range that does not interfere with the formation of a crosslinked product. Examples of the physical property adjusting agent include inorganic fillers {metal oxides such as silicon oxide, titanium oxide, aluminum oxide, magnesium oxide, zirconium oxide, zinc oxide and iron oxide, metal carbonates such as calcium carbonate and magnesium carbonate}. , Polymers {polyvinylidene fluoride, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, polymethyl methacrylate, etc.} and the like. The addition amount of the physical property adjusting agent is usually 50% by weight or less, preferably 20% by weight or less with respect to the crosslinkable monomer.

Illustrative examples of the acrylate monomer include bifunctional or higher functional unsaturated monomers.
More specific examples include bifunctional (meth) acrylates {ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, adipic acid / dineopentyl glycol ester di (meth) acrylate, polyethylene glycol having a degree of polymerization of 2 or more. Di (meth) acrylate, polypropylene glycol di (meth) acrylate having a degree of polymerization of 2 or more, polyoxyethylene / polyoxypropylene copolymer di (meth) acrylate, butanediol di (meth) acrylate, hexamethylene glycol di (meth) ) Acrylate etc.} trifunctional (meth)
Acrylate {Trimethylolpropane tri (meth) acrylate, glycerin tri (meth) acrylate, tri (meth) acrylate of ethylene oxide adduct of glycerin, tri (meth) acrylate of propylene oxide adduct of glycerin, ethylene oxide of glycerin, propylene oxide addition Object tri (meth) acrylate, etc.}, tetrafunctional or higher polyfunctional (meth) acrylate {pentaerythritol tetra (meth) acrylate,
And diglycerin hexa (meth) acrylate}. These monomers can be used alone or in combination.

A monofunctional monomer may be added to the acrylate monomer for the purpose of adjusting physical properties and the like. Examples of the monofunctional monomer include unsaturated carboxylic acids {acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, vinylbenzoic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, methylenemalonic acid, Aconitic acid, etc.}, unsaturated sulfonic acid {styrene sulfonic acid, acrylamido-2-methylpropane sulfonic acid, etc.} or salts thereof (Li salt, Na salt, K salt, ammonium salt,
Tetraalkylammonium salt, etc.), or these unsaturated carboxylic acids are partially esterified with a C1-C18 aliphatic or alicyclic alcohol, alkylene (C2-C4) glycol, polyalkylene (C2-C4) glycol, etc. (Methyl maleate, monohydroxyethyl maleate, etc.), and partially amidated with ammonia, primary or secondary amine (maleic acid monoamide, N-methyl maleic acid monoamide, N, N-diethyl maleic acid) Monoamide, etc.), (meth) acrylic acid ester [C1-C18 aliphatic (methyl, ethyl, propyl, butyl, 2-ethylhexyl, stearyl, etc.)
Ester of alcohol and (meth) acrylic acid, or alkylene (C2-C4) glycol (ethylene glycol, propylene glycol, 1,4-butanediol, etc.) and polyalkylene (C2-C4) glycol (polyethylene glycol, polypropylene glycol) With (meth) acrylic acid]; (meth) acrylamide or N-substituted (meth) acrylamide [(meth) acrylamide, N-methyl (meth) acrylamide, N-methylol (meth) acrylamide, etc.]; vinyl ester or Allyl ester [vinyl acetate, allyl acetate, etc.]; vinyl ether or allyl ether [butyl vinyl ether, dodecyl allyl ether, etc.]; unsaturated nitrile compound [(meth) acrylonitrile, crotonnitrile, etc.]; Saturated alcohols [(meth) allyl alcohol]; unsaturated amines [(meth) allylamine, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate];
Heterocycle-containing monomers [N-vinylpyrrolidone, vinylpyridine, etc.]; olefinic aliphatic hydrocarbons [ethylene,
Propylene, butylene, isobutylene, pentene, (C
6-C50) α-olefin and the like]; olefin-based alicyclic hydrocarbon [cyclopentene, cyclohexene, cycloheptene, norbornene and the like]; olefin aromatic hydrocarbon [styrene, α-methylstyrene, stilbene and the like];
Unsaturated imides [maleimide etc.]; halogen-containing monomers [vinyl chloride, vinylidene chloride, vinylidene fluoride, hexafluoropropylene etc.] and the like.

Examples of the epoxy monomer include glycidyl ethers {bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, brominated bisphenol A diglycidyl ether, phenol novolac glycidyl ether, cresol novolac glycidyl ether, etc.}, glycidyl esters { Hexahydrophthalic acid glycidyl ester, dimer acid glycidyl ester, etc.}, glycidyl amines {triglycidyl isocyanurate, tetraglycidyl diaminophenylmethane, etc.}, linear aliphatic epoxides {epoxidized polybutadiene, epoxidized soybean oil, etc.},
Alicyclic epoxides {3,4 epoxy-6 methylcyclohexyl methyl carboxylate, 3,4 epoxy cyclohexyl methyl carboxylate, etc.} and the like can be mentioned. These epoxy resins can be used alone or after curing by adding a curing agent.

Examples of the curing agent include aliphatic polyamines {diethylenetriamine, triethylenetetramine,
3,9- (3-aminopropyl) -2,4,8,10-
Tetrooxaspiro [5,5] undecane, etc., aromatic polyamines {meta-xylylenediamine, diaminophenylmethane, etc.}, polyamides {dimer acid polyamide, etc.}, acid anhydrides {phthalic anhydride, tetrahydromethyl phthalic anhydride , Hexahydrophthalic anhydride, trimellitic anhydride, methyl nadic acid anhydride}, phenols {phenol novolac, etc.}, polymercaptans {polysulfide, etc.}, tertiary amines {tris (dimethylaminomethyl) phenol, 2-ethyl-4 -Methylimidazole, etc.}, Lewis acid complex {boron trifluoride / ethylamine complex, etc.} and the like.

Examples of the monomer having an isocyanate group include toluene diisocyanate, diphenylmethane diisocyanate, 1,6-hexamethylene diisocyanate, 2,2,4 (2,2,4) -trimethyl-hexamethylene diisocyanate, p-phenylene diisocyanate. , 4,4'-dicyclohexylmethane diisocyanate, 3,3'-dimethyldiphenyl 4,4'-diisocyanate, dianisidine diisocyanate, m-xylene diisocyanate, trimethyl xylene diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, trans
Examples include -1,4-cyclohexyl diisocyanate and lysine diisocyanate.

In crosslinking the monomer having an isocyanate group, polyols and polyamines [difunctional compounds {water, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, etc.] and trifunctional compounds {glycerin, trimethylolpropane, 1,2,6-hexanetriol, triethanolamine, etc.}, tetrafunctional compound {pentaerythritol, ethylenediamine, tolylenediamine, diphenylmethanediamine, tetramethylolcyclohexane,
Methyl glucoside etc.}, 5-functional compound {2,2,6,6
-Tetrakis (hydroxymethyl) cyclohexanol, diethylenetriamine, etc., 6-functional compound {sorbitol, mannitol, dulcitol, etc.}, 8-functional compound {sucrose, etc.}, and polyether polyols {propylene oxide and / or of the above-mentioned polyol or polyamine Ethylene oxide adduct}, polyester polyol [condensation product of the above-mentioned polyol and polybasic acid {adipic acid, o, m, p-phthalic acid, succinic acid, azelaic acid, sebacic acid, ricinoleic acid],
A compound having active hydrogen, such as polycaprolactone polyol {poly ε-caprolactone etc.}, polycondensation product of hydroxycarboxylic acid, etc., can be used in combination.

A catalyst may be used in combination in the crosslinking reaction. Examples of the catalyst include organic tin compounds, trialkylphosphines, amines [monoamines {N, N-dimethylcyclohexylamine, triethylamine, etc.], cyclic monoamines {pyridine, N-methylmorpholine, etc.}, diamines { N, N, N ', N'
-Tetramethylethylenediamine, N, N, N ', N'
-Tetramethyl 1,3-butanediamine, etc.}, triamines {N, N, N ', N'-pentamethyldiethylenetriamine, etc.}, hexamines {N, N, N'N'-tetra (3-dimethylaminopropyl) ) -Methanediamine, etc.}, cyclic polyamines {diazabicyclooctane (D
ABCO), N, N'-dimethylpiperazine, 1,2-
Dimethylimidazole, 1,8-diazabicyclo (5,5
4,0) Undecene-7 (DBU), etc., and salts thereof.

The non-aqueous electrolyte battery according to the present invention is prepared by injecting an electrolyte solution before or after stacking a separator for a non-aqueous electrolyte battery and a positive electrode and a negative electrode, and finally,
It is preferably manufactured by sealing with an exterior material. Further, in a non-aqueous electrolyte battery in which a positive electrode and a negative electrode are wound around a power generation element laminated with a separator for a non-aqueous electrolyte battery, an electrolytic solution is injected into the power generation element before and after the winding. Is preferred. As the injection method, it is possible to inject at normal pressure, but a vacuum impregnation method or a pressure impregnation method can also be used.

From the viewpoint of reducing the weight of the non-aqueous electrolyte battery, the outer package is preferably a thin material, for example, a metal-resin composite material in which a metal foil is sandwiched between resin films. Specific examples of the metal foil include, but are not limited to, aluminum, iron, nickel, copper, stainless steel, titanium, gold, silver, and the like, as long as they are pinhole-free foils, and are preferably lightweight and inexpensive aluminum foils. As the resin film on the outside of the battery, a resin film having excellent puncture strength such as polyethylene terephthalate film or nylon film can be heat-sealed as the resin film on the inside of the battery such as polyethylene film or nylon film. A film that is present and has solvent resistance is preferable.

[0053]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these descriptions. (Example 1) FIG. 1 shows a cross-sectional view of a non-aqueous electrolyte battery in the battery of the present invention.

The lithium battery according to the present invention exemplified here is composed of a positive electrode group 1, a negative electrode 2 and a separator 3, a non-aqueous electrolyte and a metal resin composite film 5. In the positive electrode 1, the positive electrode mixture 11 is the positive electrode current collector 12
It is applied on top. The negative electrode 2 is formed by coating the negative electrode mixture 21 on the negative electrode current collector 22. The non-aqueous electrolyte is impregnated in the pole group 4. The metal resin composite film 5 covers the pole group 4 and is sealed on all four sides by heat welding.

Next, a method of manufacturing the battery having the above structure will be described.

The positive electrode 1 was obtained as follows. First, LiCoO2, which is a positive electrode active material, and acetylene black, which is a conductive agent, are mixed, and further, a polyvinylidene fluoride N-methyl-2-pyrrolidone solution is mixed as a binder, and this mixture is mixed with a positive electrode made of aluminum foil. After coating on one surface of the electric body 12, it was dried and pressed so that the thickness of the positive electrode mixture 11 was 0.1 mm. The positive electrode 1 was obtained through the above steps.

The negative electrode 2 was obtained as follows. First, graphite, which is a negative electrode active material, and an N-methyl-2-pyrrolidone solution of polyvinylidene fluoride, which is a binder, are mixed, and this mixture is applied to one surface of a negative electrode current collector 22 made of a copper foil. It is dried and the negative electrode mixture 21 has a thickness of 0.1.
It was pressed to have a size of mm. Through the above steps, the negative electrode 2
Got

On the other hand, a polyethylene microporous film (thickness: 25 μm, porosity: 50%) was used for the separator 5.

The electrode group 4 was constructed by placing the positive electrode mixture 11 and the negative electrode mixture 21 facing each other, disposing the separator 3 therebetween, and laminating the positive electrode 1, the separator 3 and the negative electrode 2 in this order.

The non-aqueous electrolyte was prepared by mixing 1 liter of a mixed solvent prepared by mixing ethylene carbonate, propylene carbonate and diethyl carbonate at a volume ratio of 6: 2: 2.
It was obtained by dissolving 1 mol of LiPF6 and further mixing 2% by weight of trifluoromethyl-γ-valerolactone having the structure shown in (Chemical Formula 2).

[0061]

[Chemical 2]

Next, the pole group 4 was immersed in the non-aqueous electrolyte to impregnate the pole group 4 with the non-aqueous electrolyte. Further, the electrode group 4 was covered with the metal-resin composite film 5, and its four sides were sealed by heat welding.

The non-aqueous electrolyte battery obtained by the above manufacturing method is referred to as a battery of the present invention. The design capacity of the battery of the present invention is
It is 10 mAh. (Comparative Example) As a non-aqueous electrolyte, ethylene carbonate,
1 liter of a mixed solvent in which propylene carbonate and diethyl carbonate were mixed in a volume ratio of 6: 2: 2,
A non-aqueous electrolyte battery having a capacity of 10 mAh was prepared by the same raw material and manufacturing method as in Example 1 except that 1 mol of LiPF6 was dissolved and further 2% by weight of vinylene carbonate was mixed, and Comparative battery 1 was prepared. did.

As the non-aqueous electrolyte, 1 mol of LiPF6 was dissolved in 1 liter of a mixed solvent in which ethylene carbonate, propylene carbonate and diethyl carbonate were mixed at a volume ratio of 6: 2: 2, except that 1 mol of LiPF6 was dissolved. The same raw material and the same production method as in Example 1 were used to obtain a volume of 10
A non-aqueous electrolyte battery of mAh was produced and used as a comparative battery 2. (Battery Performance Test) Next, these batteries of the present invention and comparative batteries 1 and 2 were initially charged and discharged. Initial charge is 20mA, current 2mA, final voltage 4.2.
The constant-current constant-voltage charging of V was performed, and the charging capacity at this time was defined as the initial charging capacity. The first discharge is at 20 ° C after the first charge.
A constant current discharge having a current of 2 mA and a final voltage of 2.7 V was performed, and the discharge capacity at this time was defined as an initial discharge capacity. The percentage of the initial discharge capacity with respect to the initial charge capacity was defined as the initial charge / discharge efficiency (%). The results are shown in Table 1.

[0065]

[Table 1]

As shown in Table 1, the comparative battery 2 had a very large initial charge capacity, which was about twice the designed capacity, and a very small initial discharge capacity. It is considered that this is because propylene carbonate in the non-aqueous electrolyte was decomposed on the graphite negative electrode during the initial charge, and the reversible capacity was decreased.

On the other hand, the comparative battery 1 has an initial charge capacity of about 1.2 times the designed capacity and an initial discharge capacity of about 0.
It was 85 times. This is because vinylene carbonate in the non-aqueous electrolyte decomposes on the graphite negative electrode during the initial charge, thereby forming a lithium ion-permeable protective coating on the surface of the graphite negative electrode, so that decomposition of propylene carbonate is suppressed, It is considered that the amount of electricity consumed for decomposing the vinylene carbonate was large and the excess vinylene carbonate was decomposed on the positive electrode, so that the initial discharge capacity was lowered.

On the other hand, the battery of the present invention is comparative battery 1,
It was confirmed that the non-aqueous electrolyte battery was superior in both initial charge capacity and initial discharge capacity as compared with 2, and had both high charge / discharge efficiency and high energy density. This is because trifluoromethyl-γ-valerolactone is decomposed on the graphite negative electrode at the time of first charge and forms a lithium ion permeable protective film on the surface of the graphite negative electrode.
Not only can the decomposition of propylene carbonate be reliably suppressed, the above effect can be obtained in a small amount as compared with vinylene carbonate, and even if excess trifluoromethyl-γ-valerolactone remains in the non-aqueous electrolyte, it is charged. It is considered that this has almost no effect on the discharge. Therefore, a non-aqueous electrolyte battery having high charge / discharge efficiency and high energy density can be obtained.

[0069]

As described above, according to the present invention, as described in claim 1, since the non-aqueous electrolyte contains the fluoride of the γ-butyrolactone derivative, γ-butyrolactone is initially charged. The fluoride decomposes on the graphite negative electrode and forms a lithium ion-permeable protective coating on the surface of the graphite negative electrode, so that the decomposition of other organic solvents that make up the non-aqueous electrolyte can be reliably suppressed,
It can be fully charged. Moreover, since the fluoride of the γ-butyrolactone derivative is fluorinated, it has a high oxidation resistance, almost no oxidative decomposition occurs on the positive electrode, and the addition thereof in excess does not deteriorate the battery performance. Therefore, a non-aqueous electrolyte battery having high charge / discharge efficiency and high energy density can be provided.

According to the present invention, as described in claim 2, since the negative electrode active material is graphite, it has a high operating voltage and a high energy density. Non-aqueous electrolyte battery Non-aqueous electrolyte battery Can be provided.

Further, according to the present invention, as described in claim 3, since the exterior body is made of the metal resin composite material, it is possible to provide a non-aqueous electrolyte battery having a thin shape and a reduced size and weight.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a non-aqueous electrolyte battery of the present invention.

[Explanation of symbols]

1 positive electrode 11 Positive electrode mixture 12 Positive electrode current collector 2 Negative electrode mixture 21 Negative electrode mixture 22 Negative electrode current collector 3 separator 4 pole group 5 Metal resin composite film

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5H011 AA00 CC10 DD13 HH13 JJ12                 5H029 AJ00 AJ05 AK03 AL07 AM03                       AM04 AM05 AM06 AM07 BJ03                       BJ04 DJ02                 5H050 AA08 BA17 CA02 CA08 CA09                       CB08

Claims (3)

[Claims] 1. A non-aqueous electrolyte battery comprising at least a positive electrode having a positive electrode active material as a main constituent, a negative electrode having a negative electrode active material as a main constituent, and a non-aqueous electrolyte, wherein the non-aqueous electrolyte is And a? -Butyrolactone derivative fluoride. 2. The non-aqueous electrolyte battery according to claim 1, wherein the negative electrode active material is graphite. 3. The non-aqueous electrolyte battery according to claim 1, wherein a metal resin composite material is used for an exterior body of the non-aqueous electrolyte battery.