WO2013024648A1 - Non-aqueous electrolyte secondary cell - Google Patents

Non-aqueous electrolyte secondary cell Download PDF

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Publication number
WO2013024648A1
WO2013024648A1 PCT/JP2012/067568 JP2012067568W WO2013024648A1 WO 2013024648 A1 WO2013024648 A1 WO 2013024648A1 JP 2012067568 W JP2012067568 W JP 2012067568W WO 2013024648 A1 WO2013024648 A1 WO 2013024648A1
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negative electrode
secondary battery
aqueous electrolyte
electrolyte secondary
battery according
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PCT/JP2012/067568
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French (fr)
Japanese (ja)
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緑 志村
須黒　雅博
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日本電気株式会社
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0569—Liquid materials characterised by the solvents
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0567—Liquid materials characterised by the additives
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • H01M2300/0028—Organic electrolyte characterised by the solvent
    • H01M2300/0037—Mixture of solvents
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/134—Electrodes based on metals, Si or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/386—Silicon or alloys based on silicon
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/40—Alloys based on alkali metals
    • H01M4/405—Alloys based on lithium
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to a non-aqueous electrolyte secondary battery.
  • Lithium secondary batteries have already been put into practical use as batteries for electronic devices such as laptop computers and mobile phones due to advantages such as high energy density, small self-discharge, and excellent long-term reliability.
  • electronic devices have been enhanced in functionality and used in electric vehicles, and development of lithium secondary batteries with higher energy density has been demanded. Therefore, the secondary battery using the graphite-based negative electrode material cannot satisfy the required characteristics.
  • metals capable of being alloyed with lithium such as silicon (Si) and tin (Sn), and oxides capable of inserting and extracting lithium ions have been studied as negative electrode materials.
  • Patent Document 1 discloses a negative electrode for a secondary battery including an active material layer including carbon material particles capable of inserting and extracting lithium ions, metal particles capable of being alloyed with lithium, and oxide particles capable of inserting and extracting lithium ions. Is described.
  • Patent Document 2 describes that a silicon oxide (particularly silicate) is used in a non-aqueous electrolyte secondary battery.
  • Patent Document 3 describes a negative electrode material for a secondary battery in which the surface of particles having a structure in which silicon microcrystals are dispersed in a silicon compound is coated with carbon.
  • Patent Document 4 an active material layer containing active material particles containing silicon and / or a silicon alloy and a binder is disposed on a current collector made of a conductive metal foil, and then sintered in a non-oxidizing atmosphere.
  • the negative electrode for lithium secondary batteries obtained is described. And in the secondary battery using this negative electrode, it is described that a film having high lithium ion conductivity is formed on the surface of the active material particles by adding vinylene carbonate as a solvent component of the nonaqueous electrolyte. Yes.
  • Patent Document 5 discloses an anion addition polymerization in which a nonaqueous electrolyte solution has a carbon material negative electrode capable of being doped and dedoped with lithium, and the nonaqueous electrolyte solution forms a coating on the surface of the carbonaceous negative electrode. Containing a functional monomer.
  • Patent Document 6 discloses a lithium battery using an organic electrolytic solution containing an anion polymerizable monomer into which a component capable of chelating with a lithium metal cation is introduced, a lithium salt, and an organic solvent. And it is described that an anion polymerizable monomer is polymerized at the time of initial charge to form a film on the surface of the carbon-based anode.
  • Patent Document 7 discloses a lithium secondary battery using a nonaqueous electrolytic solution containing an electrolytic oxidation polymerization monomer and an electrolytic reduction polymerization monomer. And it is described that by applying a voltage to the non-aqueous electrolyte, a polymer formed by polymerizing the monomer is formed on at least one of the positive electrode and the negative electrode.
  • Patent Document 8 a polymer electrolyte obtained by impregnating a polymer composed of polyethylene glycol dimethacrylate or polyethylene glycol diacrylate with an organic electrolyte is used. On the surface of the negative electrode, polyethylene glycol dimethacrylate or polyethylene glycol diacrylate and acrylonitrile are used. There is disclosed a lithium secondary battery in which an organic film made of is formed. However, since radical polymerization is performed in an electrolytic solution using a polymerization initiator before charging to obtain a polymer electrolyte, the monomer is consumed by radical polymerization, and it seems difficult to form a film on the negative electrode surface.
  • the negative electrode of an Example is carbon fiber, and the gas generation
  • Patent Document 9 discloses a nonaqueous electrolyte in which a negative electrode active material mainly composed of a compound containing Si and / or Sn is coated with a polymer of a compound having a specific structure containing a conjugated double bond (for example, isoprene).
  • a secondary battery is disclosed.
  • a secondary battery using a negative electrode active material containing a metal that can be alloyed with lithium has a problem in that the capacity is significantly reduced due to a charge / discharge cycle, and the storage stability is inferior. Cracking (or miniaturization) occurs due to the volume change of the negative electrode active material due to the insertion and removal of lithium ions, and gas generation due to separation from the current collector and decomposition of the electrolyte on the active surface that appears newly due to the volume change Li ion conductivity is reduced.
  • An object of the present invention is to provide a nonaqueous electrolyte secondary battery excellent in cycle characteristics and storage stability.
  • a non-aqueous electrolyte solution including a positive electrode, a separator, a negative electrode disposed to face the positive electrode with the separator interposed therebetween, a non-aqueous electrolyte solution, and an exterior body that includes them.
  • the negative electrode includes a negative electrode active material containing a metal (a) that can be alloyed with lithium, and a binder.
  • a non-aqueous electrolyte secondary battery is provided in which the non-aqueous electrolyte contains a vinyl compound having a plurality of terminal double bonds.
  • a non-aqueous electrolyte secondary battery excellent in cycle characteristics and storage stability can be provided.
  • FIG. 1 is a schematic cross-sectional view for explaining the structure of a laminated laminate type secondary battery according to an embodiment of the present invention.
  • a secondary battery includes a positive electrode, a separator, an electrode laminate including a negative electrode disposed opposite to the positive electrode with the separator interposed therebetween, a non-aqueous electrolyte, and an outer package that contains them.
  • This negative electrode contains a negative electrode active material containing a metal (a) that can be alloyed with lithium and a binder, and this non-aqueous electrolyte comprises a vinyl compound having a plurality of terminal double bonds (hereinafter referred to as “polyfunctional vinyl” as appropriate). Compound)).
  • the electrode laminated body in one container which consists of this exterior body can contain one or two or more electrode pairs of a positive electrode and a negative electrode.
  • the secondary battery according to the present embodiment may have a laminated laminate type structure in which such an electrode laminate is packaged with a laminate film.
  • This polyfunctional vinyl compound preferably has radical polymerization or anion polymerization performance, and can form a film on the negative electrode. Thereby, cycle characteristics and storage stability can be improved.
  • the terminal double bond (terminal carbon-carbon double bond) is not limited to the vinyl group (CH 2 ⁇ CH—).
  • the content of the polyfunctional vinyl compound in the nonaqueous electrolytic solution is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and further preferably 0.5% by mass or more from the viewpoint of obtaining a sufficient addition effect.
  • 0.01% by mass or more more preferably 0.1% by mass or more, and further preferably 0.5% by mass or more from the viewpoint of obtaining a sufficient addition effect.
  • Excessive addition of the polyfunctional vinyl compound causes an increase in cost and an increase in resistance, so it is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less.
  • non-aqueous electrolyte a solution obtained by dissolving a supporting salt in a mixed solution of a polyfunctional vinyl compound and a non-aqueous solvent can be used.
  • an electropolymerization reaction of the polyfunctional vinyl compound occurs on the negative electrode surface at a base potential, and a thin polymer film is formed on the negative electrode surface. Since this polymer film is polymerized using an active species on the surface of the lithium alloy negative electrode (for example, silyl lithium, silyloxy lithium, etc. in the case of a silicon negative electrode) as an initiator, a film can be selectively formed on the negative electrode surface. The reaction between the active species on the surface of the alloy negative electrode and the electrolytic solution can be suppressed. Furthermore, since this vinyl compound is polyfunctional, the polymer film formed by electrolytic polymerization becomes a three-dimensional crosslinked body, and is excellent in high stretchability and high strength.
  • an active species on the surface of the lithium alloy negative electrode for example, silyl lithium, silyloxy lithium, etc. in the case of a silicon negative electrode
  • the thickness of the polymer film can be controlled by the amount of the polyfunctional vinyl compound added, a very thin film having high lithium ion conductivity can be formed.
  • a polymer film obtained only from a (monofunctional) vinyl compound containing one double bond is composed of a chain polymer, so that the strength is low, and the polymer film may be dissolved in the electrolytic solution.
  • a film is formed by the decomposition reaction of the non-aqueous solvent on the negative electrode surface, but the obtained film is made of lithium carbonate, alkyl lithium, etc.
  • Inorganic compounds and low molecular weight organic compounds are fragile and difficult to follow the volume change of the lithium alloy negative electrode.
  • new active species appear due to the refinement of the active material that accompanies the insertion / extraction of lithium ions, and thus the reaction of the electrolytic solution cannot be sufficiently suppressed.
  • the polyfunctional vinyl compound in the non-aqueous electrolyte preferably has radical polymerization or anion polymerization performance because the electrolytic polymerization occurs using an anion radical generated on the surface of the lithium alloy negative electrode during initial charging as an initiator.
  • a polymer film chemically bonded to the negative electrode surface is formed by polymerizing the active species on the surface of the lithium alloy negative electrode as a starting point, so that a stable film can be formed. preferable.
  • Such a polyfunctional vinyl compound preferably has a basic structure represented by the formula (1A), (1B) or (1C).
  • V 1 , V 2 , V 3 and V 4 each independently represent a double bond-containing group
  • X 1 represents a linking group to which the double bond-containing group is bonded.
  • the double bond-containing groups V 1 , V 2 , V 3 and V 4 include a methacryloyl group (formula 2), an acryloyl group (formula 3), a vinylphenyl group (formula 4), a 1,3-butadienyl group (formula 5 ), A cyanoacryloyl group (formula 6).
  • the combination of the double bond-containing groups may be the same or different, but a vinyl compound having the same double bond-containing group is preferable because the polymerization reaction proceeds uniformly and a more uniform film is formed. .
  • the linking group X 1 linking the double bond-containing group is a saturated hydrocarbon polyvalent group such as an alkylene group or cycloalkylene (preferably having 1 to 12 carbon atoms); an alkylene oxide unit such as an ethylene oxide unit or a methylene oxide unit
  • a polyvalent group containing a polyether chain is preferable because lithium ion conductivity is increased.
  • a vinyl compound having an ether bond or an amide bond is preferable because lithium ion conductivity is increased by coordination with lithium ions.
  • a vinyl compound containing a saturated hydrocarbon structure such as an alkylene group or a fluorinated hydrocarbon structure such as an aromatic ring or a fluoroalkylene group is imparted with hydrophobicity to the film formed on the negative electrode surface. This is preferable because the effect of suppressing the reaction is increased.
  • a vinyl compound containing a carbonate group or an ester group is preferable because compatibility with the electrolytic solution is improved.
  • a vinyl compound containing an ether bond, an alkylene group, or a siloxane chain is preferable because a highly stretchable film is formed.
  • polyfunctional vinyl compound examples include ethylene glycol di (meth) acrylate, 1,3-propanediol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, 1,2-butanediol di (meth) acrylate, 2,3-butanediol di (meth) acrylate, 1-methyl-1,3-propanediol di (meth) Acrylate, 2-methyl-1,3-propanediol di (meth) acrylate, 2-methyl-1,2-propanediol di (meth) acrylate, 1,5-pentanediol di (meth) acrylate, 1,6- Hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) a Relate,
  • polyfunctional vinyl compound examples include trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, glycerin tri (meth) acrylate, ethoxylated glycerin tri (meth) acrylate, trimethylolpropane tri ( (Meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, PO-modified trimethylolpropane tri (meth) acrylate, EO / PO-modified trimethylolpropane tri (meth) acrylate, castor oil-modified tri (meth) acrylate, ethoxylated isocyanuric Acid triacrylate, ⁇ -caprolactone modified tris- (2-acryloxyethyl) isocyanurate, pentaerythritol tri (meth) acrylate, ethoxylated pentae Multifunctional such as sitolito
  • polyfunctional vinyl compound examples include conjugated dienes such as butadiene and isoprene, polyfunctional fragrances such as divinylbenzene, 1,2,4-trivinylbenzene, 1,3,5-trivinylbenzene, and divinylnaphthalene.
  • conjugated dienes such as butadiene and isoprene
  • polyfunctional fragrances such as divinylbenzene, 1,2,4-trivinylbenzene, 1,3,5-trivinylbenzene, and divinylnaphthalene.
  • Group vinyl compounds examples include conjugated dienes such as butadiene and isoprene, polyfunctional fragrances such as divinylbenzene, 1,2,4-trivinylbenzene, 1,3,5-trivinylbenzene, and divinylnaphthalene.
  • the polyfunctional vinyl compound can be synthesized by a reaction between a chloride having a vinyl group (acryloyl chloride, methacryloyl chloride, chloromethylstyrene, etc.) and a polyol having a plurality of hydroxyl groups.
  • a chloride having a vinyl group acryloyl chloride, methacryloyl chloride, chloromethylstyrene, etc.
  • polyols having two or more hydroxyl groups include dihydric alcohols such as ethylene glycol, propylene glycol, dipropylene glycol, 1,3- and 1,4-butanediol, and 1,6-hexanediol, glycerin, and trimethylol.
  • Trivalent alcohols such as propane, trimethylolethane and hexanetriol, tetrahydric alcohols such as pentaerythritol, methylglycoside and diglycerin, polyglycerin such as triglycerin and tetraglycerin, polypentaerythritol such as dipentaerythritol and tripentaerythritol , Cycloalkane polyols such as tetrakis (hydroxymethyl) cyclohexanol, and polyvinyl alcohol.
  • tetrahydric alcohols such as pentaerythritol, methylglycoside and diglycerin
  • polyglycerin such as triglycerin and tetraglycerin
  • polypentaerythritol such as dipentaerythritol and tripentaerythritol
  • Cycloalkane polyols such as tetrakis
  • sugar alcohols such as adonitol, arabitol, xylitol, sorbitol, mannitol, iditol, tallitol, dulcitol, and sugars such as glucose, mannose glucose, mannose, fructose, sorbose, sucrose, lactose, raffinose, and cellulose can be used.
  • the polyhydric phenol include monocyclic polyhydric phenols such as pyrogallol, hydroquinone and phloroglucin, bisphenols such as bisphenol A and bisphenol sulfone, and phenol / formaldehyde condensates (novolaks).
  • a polyfunctional vinyl compound By using such a polyfunctional vinyl compound, the polymer film formed by the electrolytic polymerization reaction on the surface of the lithium alloy negative electrode becomes a three-dimensional crosslinked body, and a film excellent in stretchability and strength can be formed.
  • a polyfunctional vinyl compound can be used individually by 1 type or in combination of 2 or more types.
  • a mixture of a polyfunctional vinyl compound and a monofunctional vinyl compound may be used as long as the desired effect of the polyfunctional vinyl compound is not impaired.
  • the monofunctional vinyl compound examples include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl ( (Meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, methoxyethyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, N, N-dimethylaminoethyl (meth) ) Acrylate, isobornyl (meth) acrylate, ethoxylated o-phenylphenol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, phenoxypolyethyleneglycol (
  • the monofunctional vinyl compound examples include aromatic vinyls such as styrene, vinyl toluene, ⁇ -methyl styrene, vinyl naphthalene, ethylene, propylene, 1-butene, isobutene, 1-pentene, 3-methyl-1 Alkenes such as -butene, 4-methyl-1-pentene, 1-hexene, vinylcyclohexane, cyclobutene, cyclopentene, cyclohexene and the like can be mentioned.
  • aromatic vinyls such as styrene, vinyl toluene, ⁇ -methyl styrene, vinyl naphthalene, ethylene, propylene, 1-butene, isobutene, 1-pentene, 3-methyl-1 Alkenes such as -butene, 4-methyl-1-pentene, 1-hexene, vinylcyclohexane, cyclobutene, cyclopentene, cyclohexene and the
  • a non-aqueous electrolyte using a polyfunctional vinyl compound and vinylene carbonate can also be used.
  • the decomposition reaction of vinylene carbonate occurs on the negative electrode surface at a base potential, and a film of vinylene carbonate decomposition product is formed on the negative electrode surface.
  • a double bond derived from vinylene carbonate remains, and this double bond reacts with the vinyl group of the polyfunctional vinyl compound, so that the decomposition product film forms a cross-linked structure. It becomes a strong film and can suppress the reaction between the active species on the surface of the lithium alloy negative electrode and the electrolytic solution.
  • this film is a three-dimensional crosslinked body, it is excellent in high stretchability and high strength. Accordingly, it is possible to follow the volume change of the lithium alloy negative electrode, and it is possible to prevent the negative electrode active material from being miniaturized. Since the thickness of the film can be controlled by the amount of vinylene carbonate and polyfunctional vinyl compound added, a very thin film having high lithium ion conductivity can be formed. In a non-aqueous electrolyte solution containing only vinylene carbonate, a coating film is formed by the decomposition reaction of the non-aqueous solvent on the negative electrode surface, but the obtained coating film is brittle and it is difficult to follow the volume change of the lithium alloy negative electrode.
  • the addition amount of the vinyl compound with respect to the non-aqueous solvent can be set in a range of 0.01 to 10% by mass, and is preferably 0.1% by mass or more from the viewpoint of obtaining a sufficient addition effect. 0.5 mass% or more is more preferable, and 5 mass% or less is preferable in the range in which a desired effect is acquired, 3 mass% or less is more preferable, and it can also set to 2 mass% or less.
  • the content rate of vinylene carbonate and a polyfunctional vinyl compound in a non-aqueous electrolyte is 0.01 mass% or more, respectively.
  • 0.1 mass% or more is more preferable, 0.5 mass% or more is more preferable, 5 mass% or less is preferable, 3 mass% or less is more preferable, and 1 mass% or less is further preferable.
  • the total content of vinylene carbonate and polyfunctional vinyl compound is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, further preferably 1% by mass or more, and preferably 10% by mass or less, 5 mass% or less is more preferable, and 3 mass% or less is further more preferable.
  • the content ratio of the monofunctional vinyl compound relative to the total amount of these is 70 mass% or less is preferable, 60 mass% or less is more preferable, and 50 mass% or less is further more preferable.
  • non-aqueous solvent those usually used as the solvent for the non-aqueous electrolyte can be used. Specific examples thereof include carbonates, chlorinated hydrocarbons, ethers, ketones, esters, and nitriles.
  • non-aqueous solvents having a high dielectric constant such as ethylene carbonate (EC), propylene carbonate (PC), ⁇ -butyrolactone (GBL), and those obtained by fluorine substitution thereof, diethyl carbonate (DEC),
  • DMC dimethyl carbonate
  • EMC ethyl methyl carbonate
  • Examples of the supporting salt include LiPF 6 , LiAsF 6 , LiAlCl 4 , LiClO 4 , LiBF 4 , LiSbF 6 , LiCF 3 SO 3 , LiC 4 F 9 SO 3 , Li (CF 3 SO 2 ) 2 , LiN (CF 3 SO 2 ) A lithium salt such as 2 .
  • the supporting salt can be used alone or in combination of two or more.
  • the non-aqueous electrolyte is effective when a metal (a) that can be alloyed with lithium is used as a specific negative electrode, that is, a negative electrode active material, and in particular, occludes the metal (a) and lithium ions. It is more effective when the metal oxide (b) that can be released and the carbon material (c) that can occlude and release lithium ions are used.
  • the shape of the non-aqueous electrolyte secondary battery according to the present embodiment includes a cylindrical shape, a flat wound rectangular shape, a laminated rectangular shape, a coin shape, a flat wound laminated shape, and a laminated laminated shape. From the viewpoint described later, a laminated laminate type is preferable.
  • FIG. 1 is a schematic cross-sectional view showing an example of an electrode laminate of a laminated laminate type nonaqueous electrolyte secondary battery.
  • the exterior body is omitted.
  • the positive electrode 3 and the negative electrode 1 are alternately stacked via the separator 2.
  • the positive electrode current collector 5 of each positive electrode 3 is welded to and electrically connected to each other at an end portion not covered with the positive electrode active material, and the positive electrode terminal 6 is welded to the welded portion.
  • a negative electrode current collector 4 included in each negative electrode 1 is welded to and electrically connected to each other at an end portion not covered with the negative electrode active material, and a negative electrode terminal 7 is welded to the welded portion.
  • This electrode laminate is housed in a container formed of a laminate film as an exterior body, and an electrolyte is injected and sealed.
  • a laminated battery (laminated laminated battery) having such a planar laminated structure has a smaller R portion (for example, a wound core with a wound structure) than a battery having a wound structure (winded battery). Therefore, there is an advantage that it is difficult to be adversely affected by the volume change of the electrode accompanying charging / discharging.
  • the electrode since the electrode is curved in the wound type battery, the structure is easily distorted when a volume change occurs in the electrode. Such distortion is particularly noticeable when a negative electrode active material having a large volume change associated with charge / discharge, such as a silicon-based active material, is used.
  • a laminated laminate battery is suitable when an active material having a large volume change associated with charge / discharge is used.
  • planar laminated structure means that each laminated electrode is a sheet-like material, and each electrode is laminated in a planar shape (the outer peripheral edge of the sheet-like material is at the peripheral edge of the laminated structure) It is distinguished from a structure in which the electrode stack is bent or a structure in which the electrode stack is wound.
  • such a laminated laminate type battery has a problem that when the gas is generated between the electrodes, the generated gas tends to stay between the electrodes. This is because in the wound battery, the distance between the electrodes is difficult to increase because tension is applied to the electrodes, whereas in the laminated laminate battery, the distance between the electrodes is likely to increase. This problem is particularly noticeable when the outer package is an aluminum laminate film. Further, when the electrolytic solution contains a carbonate ester solvent or a carboxylic acid ester solvent, this problem becomes even more remarkable.
  • a long-life drive can be performed even in a laminated non-aqueous electrolyte secondary battery using a high energy negative electrode that easily generates gas.
  • the negative electrode in the present embodiment includes a current collector and an active material layer on the current collector, and the active material layer includes a binder and a negative electrode active material.
  • the binder binds between the active material particles and between the active material particles and the current collector.
  • the negative electrode active material in the present embodiment includes a metal (a) that can be alloyed with lithium, and further preferably includes a metal oxide (b) that can occlude and release lithium ions, and further occludes and releases lithium ions. It is more preferable that the carbon material (c) which can be obtained is included.
  • the metal (a) Al, Si, Pb, Sn, In, Bi, Ag, Ba, Ca, Hg, Pd, Pt, Te, Zn, La, or an alloy containing two or more of these is used. it can.
  • silicon (Si) or a silicon-containing metal is preferable as the metal (a), and silicon is more preferable.
  • silicon oxide, aluminum oxide, tin oxide, indium oxide, zinc oxide, lithium oxide, or a composite oxide containing two or more of these can be used.
  • silicon oxide is preferably included as the metal oxide (b). This is because silicon oxide is relatively stable and does not easily react with other compounds.
  • one or more elements selected from nitrogen, boron and sulfur may be added to the metal oxide (b), for example, 0.1 to 5% by mass. By carrying out like this, the electrical conductivity of a metal oxide (b) can be improved.
  • the metal oxide (b) preferably has an amorphous structure in whole or in part.
  • the metal oxide (b) having an amorphous structure can suppress the volume expansion of the carbon material (c) and the metal (a), which are other negative electrode active material components, and can suppress the decomposition of the nonaqueous electrolytic solution. Although this mechanism is not clear, it is presumed that the metal oxide (b) has an amorphous structure, so that there is some influence on the film formation at the interface between the carbon material (c) and the non-aqueous electrolyte.
  • the amorphous structure is considered to have relatively few elements due to non-uniformity such as crystal grain boundaries and defects.
  • the metal (a) is entirely or partially dispersed in the metal oxide (b).
  • the metal oxide (b) By dispersing at least a part of the metal (a) in the metal oxide (b), the volume expansion of the whole negative electrode can be further suppressed, and the decomposition of the non-aqueous electrolyte can also be suppressed.
  • all or part of the metal (a) is dispersed in the metal oxide (b) because of observation with a transmission electron microscope (general TEM observation) and energy dispersive X-ray spectroscopy (general). This can be confirmed by using a combination of a standard EDX measurement. Specifically, the cross section of the sample containing the metal (a) is observed, the oxygen concentration of the particles dispersed in the metal oxide (b) is measured, and the metal (a) constituting the particles is It can be confirmed that it is not an oxide.
  • the metal oxide (b) is preferably an oxide of a metal constituting the metal (a). More preferably, the metal (a) is simple silicon and the metal oxide (b) is silicon oxide.
  • the negative electrode active material containing metal (a) and metal oxide (b) can be obtained, for example, by sintering metal (a) and metal oxide (b) under high temperature and reduced pressure. Or it can obtain by mixing a metal (a) and a metal oxide (b) by mechanical milling.
  • the active material thus formed can be coated with carbon. For example, there are a method of mixing and baking this active material and an organic compound, and a method of introducing this active material into a gas atmosphere of an organic compound such as methane and performing thermal CVD.
  • the carbon material (c) graphite, amorphous carbon, diamond-like carbon, carbon nanotube, or a composite containing two or more of these can be used.
  • graphite with high crystallinity has high electrical conductivity, and is excellent in adhesiveness and voltage flatness with a positive electrode current collector made of a metal such as copper. Therefore, it is advantageous in designing a secondary battery with high output and high energy.
  • amorphous carbon having low crystallinity has a relatively small volume expansion, it has a high effect of relaxing the volume expansion of the entire negative electrode, and deterioration due to non-uniformity such as crystal grain boundaries and defects hardly occurs. Therefore, it is advantageous in designing a secondary battery having a long life and high robustness.
  • the negative electrode active material that is a composite of the metal (a), the metal oxide (b), and the carbon material (c), all or part of the metal oxide (b) has an amorphous structure, and the metal (a) What disperse
  • a negative electrode active material can be produced, for example, by the method described in Patent Document 3 (Japanese Patent Laid-Open No. 2004-47404).
  • the metal oxide (b) is disproportionated at 900 to 1400 ° C. in an atmosphere containing an organic compound gas such as methane gas and a thermal CVD process is performed. Thereby, the metal element in metal oxide (b) can be clustered as a metal (a), and the composite body by which the surface was coat
  • This composite can be used as a negative electrode active material.
  • the negative electrode active material containing the metal (a), the metal oxide (b), and the carbon material (c) can also be produced by mixing by mechanical milling.
  • the content of the metal (a) in the negative electrode active material is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more from the viewpoint of obtaining a sufficient addition effect (such as charge / discharge capacity). From the viewpoint of sufficiently obtaining the effect of adding other components, etc., it is preferably 95% by mass or less, more preferably 90% by mass or less, further preferably 80% by mass or less, and can also be 50% by mass or less.
  • the content of the metal oxide (b) in the negative electrode active material is preferably 5% by mass or more, more preferably 15% by mass or more, and further preferably 40% by mass or more from the viewpoint of charge / discharge cycle characteristics and the like. , 50% by mass or more. 90 mass% or less is preferable from the point which fully obtains the addition effect of another component, etc., 80 mass% or less is more preferable, and 70 mass% or less is further more preferable.
  • the mass ratio (a / b) of the metal (a) and the metal oxide (b) in the negative electrode active material is not particularly limited. Can be set in the range of 5/95 to 90/10, can be set in the range of 10/90 to 80/20, and can be set in the range of 30/70 to 60/40. it can.
  • the content of the carbon material (c) in the negative electrode active material is preferably 1% by mass or more, more preferably 2% by mass or more from the viewpoint of obtaining a sufficient addition effect, and sufficient effects of addition of other components, etc. are obtained. From the viewpoint, 50% by mass or less is preferable, and 30% by mass or less is more preferable.
  • the ratio of the metal (a), the metal oxide (b), and the carbon material (c) is not particularly limited. Although not, it can be set according to the above range of the content.
  • the content ratio of the metal (a) is, for example, preferably 5% by mass or more, more preferably 10% by mass or more, and 20% by mass with respect to the total of the metal (a), the metal oxide (b), and the carbon material (c). % Or more is more preferable, 90 mass% or less is preferable, 80 mass% or less is more preferable, and it can also be set to 50 mass% or less.
  • the content ratio of the metal oxide (b) is preferably, for example, 5% by mass or more, more preferably 15% by mass or more, with respect to the total of the metal (a), the metal oxide (b), and the carbon material (c). It can also be set to 40% by mass or more, preferably 90% by mass or less, more preferably 80% by mass or less, and can also be set to 70% by mass or less.
  • the content ratio of the carbon material (c) is, for example, preferably 1% by mass or more, more preferably 2% by mass or more, with respect to the total of the metal (a), the metal oxide (b), and the carbon material (c). 50 mass% or less is preferable and 30 mass% or less is more preferable.
  • the shape of the metal (a), the metal oxide (b), and the carbon material (c) is not particularly limited, but may be particulate.
  • the specific surface area of the negative electrode active material is preferably 0.2 m 2 / g or more, more preferably 1.0 m 2 / g or more, still more preferably 2.0 m 2 / g or more, while 9.0 m 2 / g or less.
  • 8.0 m 2 / g or less is more preferable, and 7.0 m 2 / g or less is more preferable.
  • the specific surface area is obtained by an ordinary BET specific surface area measurement method.
  • the average particle diameter of the negative electrode active material is preferably 0.01 ⁇ m or more, more preferably 0.1 ⁇ m or more, further preferably 0.2 ⁇ m or more, and on the other hand, 30 ⁇ m or less is more preferable, and 20 ⁇ m or less is more preferable.
  • the average particle diameter is 50% cumulative diameter D 50 (median diameter), and is obtained by particle size distribution measurement by a laser diffraction scattering method.
  • binder for the negative electrode examples include polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, styrene-butadiene copolymer rubber, polytetrafluoroethylene, polypropylene, polyethylene, Polyimide, polyamideimide, or the like can be used. Of these, polyimide or polyamideimide is preferred because of its high binding properties.
  • the content of the binder for the negative electrode in the negative electrode is preferably 5 to 25 parts by mass, and 7 to 20 parts by mass with respect to 100 parts by mass of the negative electrode active material, from the viewpoints of binding force and energy density that are in a trade-off relationship. Is more preferable.
  • the negative electrode current collector copper, nickel, and silver are preferable in view of electrochemical stability.
  • the shape include foil, flat plate, and mesh.
  • the negative electrode can be produced, for example, by forming a negative electrode active material layer containing a negative electrode active material and a negative electrode binder on a negative electrode current collector.
  • the negative electrode active material layer can be formed by a general slurry coating method. Specifically, a negative electrode is prepared by preparing a slurry containing a negative electrode active material, a binder, and a solvent, applying the slurry onto a negative electrode current collector, drying, compressing and molding as necessary. can do.
  • the negative electrode slurry can be obtained by dispersing and kneading the negative electrode active material in a solvent such as N-methyl-2-pyrrolidone (NMP) together with the negative electrode binder.
  • NMP N-methyl-2-pyrrolidone
  • Examples of the method for applying the negative electrode slurry include a doctor blade method, a die coater method, and a dip coating method.
  • a metal thin film may be formed by a method such as vapor deposition or sputtering, and this metal thin film may be used as a negative electrode current collector.
  • Positive electrode for example, a positive electrode having a positive electrode active material layer containing a positive electrode active material and a positive electrode binder on a positive electrode current collector can be used.
  • lithium manganate having a layered structure such as LiMnO 2 or LixMn 2 O 4 (0 ⁇ x ⁇ 2) or a spinel structure; lithium metal in which a part of Mn of lithium manganate is replaced with another metal Oxides; LiCoO 2 , LiNiO 2 , lithium metal oxides in which some of these transition metals (Co, Ni) are replaced with other metals; specificities such as LiNi 1/3 Co 1/3 Mn 1/3 O 2 Transition metal oxides that do not exceed half the total number of transition metals (atomic ratio); lithium metal oxides that contain Li in excess of the stoichiometric composition in these lithium transition metal oxides, etc. .
  • ⁇ ⁇ 0.1 and ⁇ ⁇ 0.01 can be set.
  • a positive electrode active material can be used individually by 1 type or in combination of 2 or more types.
  • the positive electrode binder the same negative electrode binder as that used for normal negative electrodes can be used.
  • polyvinylidene fluoride is preferable from the viewpoint of versatility and low cost.
  • the amount of the positive electrode binder used is preferably 2 to 10 parts by mass with respect to 100 parts by mass of the positive electrode active material, from the viewpoints of binding force and energy density which are in a trade-off relationship.
  • the positive electrode current collector for example, aluminum, nickel, silver, SUS, valve metal, or an alloy thereof can be used from the viewpoint of electrochemical stability.
  • the shape include foil, flat plate, and mesh.
  • an aluminum foil can be preferably used.
  • a conductive auxiliary material may be added to the positive electrode active material layer containing the positive electrode active material for the purpose of reducing impedance.
  • the conductive auxiliary material include carbonaceous fine particles such as graphite, carbon black, and acetylene black.
  • the positive electrode is prepared by, for example, preparing a slurry containing a positive electrode active material, a binder, and a solvent (and, if necessary, a conductive auxiliary material), applying the slurry onto the negative electrode current collector, and drying the slurry.
  • a positive electrode active material layer can be produced by forming a positive electrode active material layer.
  • separator As the separator, a polyolefin such as polypropylene or polyethylene, a porous film or a nonwoven fabric made of a fluororesin, or the like can be used. Moreover, what laminated
  • Electrode pair examples include a cylindrical wound structure, a flat wound structure, a zigzag folded structure, and a laminated laminate structure, and a laminated laminate structure is particularly preferable.
  • the electrodes and the separator are laminated in a planar shape, and there is no portion with a small R (a region close to the winding core of the wound structure or a region corresponding to the folded portion). Therefore, when an active material having a large volume change associated with charging / discharging is used, it is less likely to be adversely affected by the volume change of the electrode associated with charging / discharging than a battery having a wound structure.
  • Exterior Body As the exterior body, a laminate film that is stable in a non-aqueous electrolyte and has a sufficient water vapor barrier property can be used.
  • a laminate film such as polypropylene or polyethylene coated with aluminum or silica can be used.
  • aluminum laminate film it is preferable to use an aluminum laminate film from the viewpoints of versatility and cost.
  • the volume change of the battery or the electrode Distortion is likely to occur. This is because the laminate film is more easily deformed by the internal pressure of the nonaqueous electrolyte secondary battery than the metal can. Furthermore, when sealing a non-aqueous electrolyte secondary battery using a laminate film as an outer package, the internal pressure of the battery is usually lower than atmospheric pressure and there is no extra space inside. When this occurs, it tends to immediately lead to battery volume changes and electrode deformation.
  • the nonaqueous electrolyte secondary battery according to the present embodiment can suppress the occurrence of such a problem. Thereby, a laminated laminate type non-aqueous electrolyte secondary battery having excellent long-term reliability can be provided.
  • an assembled battery in which a plurality of the secondary batteries (single cells) described above are electrically connected and packed with a tube or a case.
  • the cells in the assembled battery can be connected in series, in parallel, or both.
  • the capacity and voltage can be adjusted according to the number of cells and the connection method.
  • a plurality of the assembled batteries can be connected in series or in parallel.
  • the above-mentioned secondary battery or assembled battery can be used as a power source for driving a vehicle, and can provide a vehicle with a long life and high reliability.
  • the vehicle can be applied to a hybrid vehicle, an electric vehicle, an electric motorcycle, an electric assist bicycle, and the like. It is not limited to a four-wheel vehicle or a two-wheel vehicle, and a three-wheel vehicle is also included, and the number of wheels is not limited. Furthermore, it can be applied to various power sources for moving / transporting media such as trains.
  • Example 1 Silicon oxide powder (mixture of silicon oxide and silicon) is subjected to CVD treatment at 1150 ° C. for 6 hours in an atmosphere containing methane gas, so that silicon in silicon oxide is nanoclustered and silicon is coated with carbon. A silicon oxide-carbon composite (negative electrode active material) was obtained. The mass ratio of silicon / silicon oxide / carbon was adjusted to be 29/61/10.
  • Name: U Varnish A was weighed and mixed with n-methylpyrrolidone to prepare a negative electrode slurry.
  • This negative electrode slurry was applied on the surface of a copper foil having a thickness of 10 ⁇ m so as to be 2.5 mg per 1 cm 2 and dried.
  • the negative electrode slurry was applied to the back surface of the copper foil and dried. Thereafter, heat treatment was performed at 350 ° C. in a nitrogen atmosphere, and cut into 26 mm ⁇ 65 mm to obtain a negative electrode.
  • a positive electrode slurry was prepared by weighing at a mass ratio of 5: 5 (active material: conductive auxiliary agent: binder) and mixing them with n-methylpyrrolidone.
  • This positive electrode slurry was applied to the surface of an aluminum foil having a thickness of 20 ⁇ m so as to have an amount of 20 mg per cm 2 , dried and pressed.
  • the positive electrode slurry was applied to the back surface of the aluminum foil, dried, and pressed. Then, it cut
  • LiPF 6 is dissolved in a non-aqueous solvent mixed with EC / DEC at 3/7 (volume ratio) to a concentration of 1 mol / L, and ethylene glycol dimethacrylate as a vinyl compound has a concentration of 2 wt%.
  • a nonaqueous electrolytic solution was obtained.
  • the electrode laminate is wrapped with an aluminum laminate film as an outer package so that tabs (terminals) come out, and after injecting a nonaqueous electrolyte, it is sealed under reduced pressure to obtain a nonaqueous electrolyte secondary battery. It was.
  • Example 2 A nonaqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that 2 wt% of diethylene glycol dimethacrylate was dissolved instead of ethylene glycol dimethacrylate.
  • Example 1 A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that the vinyl compound was not dissolved in the non-aqueous solvent.
  • Example 2 A nonaqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that 2 wt% of methyl methacrylate was dissolved in place of ethylene glycol dimethacrylate.
  • Example 3 A nonaqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that 1 wt% of butyl vinyl ether was dissolved instead of ethylene glycol dimethacrylate.
  • Example 4 A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that 2 wt% of vinylene carbonate was dissolved in place of ethylene glycol dimethacrylate.
  • Volume increase rate (%) 100 ⁇ (volume after standing for one week ⁇ initial volume) / initial volume Evaluation was evaluated according to the following criteria.
  • Capacity retention rate (%) 100 ⁇ (discharge capacity at the 100th cycle) / (discharge capacity at the first cycle) Evaluation was determined according to the following criteria.
  • Capacity maintenance rate exceeds 85%
  • B Capacity maintenance rate is over 80% and 85% or less
  • C Capacity maintenance rate is over 70% and 80% or less
  • D Capacity maintenance rate is 70% or less.
  • the nonaqueous electrolyte secondary batteries of Examples 1 and 2 showed excellent results (low volume increase rate and high capacity retention rate) in the storage test and cycle test at 60 ° C. This is presumably because a polymer film is formed on the negative electrode surface by electrolytic polymerization of the polyfunctional vinyl compound contained in the non-aqueous electrolyte.
  • Comparative Examples 2 and 3 have a lower volume increase rate than Comparative Example 1 in which no vinyl compound is added, but are significantly larger than Examples 1 and 2, and can sufficiently suppress the decomposition of the electrolyte. You can see that it is not. Moreover, it turns out that the vinyl compound used in Comparative Examples 2 and 3 does not show the effect of improving cycle characteristics (capacity maintenance ratio). Since the butyl vinyl ether of Comparative Example 4 reacted with the supporting salt due to cationic polymerization and gelled, the capacity did not increase, the volume increase in the 60 ° C. storage test was not observed, and the capacity retention rate of the 60 ° C. cycle test was also low. As a result.
  • a non-aqueous electrolyte secondary battery having high energy density and excellent long-term stability can be provided.
  • This embodiment can be used in all industrial fields that require a power source and in industrial fields related to the transport, storage, and supply of electrical energy.
  • power sources for mobile devices such as mobile phones and laptop computers
  • power sources for electric vehicles such as electric cars, hybrid cars, electric motorcycles, electric assist bicycles, and trains
  • power sources for mobile and transport media such as satellites and submarines
  • a backup power source such as a UPS (uninterruptible power supply); a power storage facility for storing power generated by solar power generation, wind power generation, or the like.
  • UPS uninterruptible power supply

Abstract

A non-aqueous electrolyte secondary cell including a positive electrode, a separator, a negative electrode arranged so as to face the positive electrode with the separator interposed therebetween, a non-aqueous electrolyte, and an outer case encompassing the abovementioned elements. The negative electrode includes a negative electrode active material that contains a metal capable of forming an alloy with lithium, and a binder. The non-aqueous electrolyte contains a vinyl compound having a plurality of terminal double bonds.

Description

非水電解液二次電池Non-aqueous electrolyte secondary battery
　本発明は、非水電解液二次電池に関する。 The present invention relates to a non-aqueous electrolyte secondary battery.
　リチウム二次電池は、エネルギー密度が高く、自己放電が小さく、長期信頼性に優れる等の利点により、ノート型パソコンや携帯電話などの電子機器用の電池としてすでに実用化されている。しかし、近年では電子機器の高機能化や電気自動車への利用が進み、よりエネルギー密度の高いリチウム二次電池の開発が求められている。そのため、黒鉛系負極材料を用いた二次電池では要求特性を満たすことができなくなっている。 Lithium secondary batteries have already been put into practical use as batteries for electronic devices such as laptop computers and mobile phones due to advantages such as high energy density, small self-discharge, and excellent long-term reliability. However, in recent years, electronic devices have been enhanced in functionality and used in electric vehicles, and development of lithium secondary batteries with higher energy density has been demanded. Therefore, the secondary battery using the graphite-based negative electrode material cannot satisfy the required characteristics.
　そこで、エネルギー密度を向上する観点から、負極材料として、シリコン（Ｓｉ）、スズ（Ｓｎ）などのリチウムと合金可能な金属や、リチウムイオンを吸蔵、放出し得る酸化物が検討されている。 Therefore, from the viewpoint of improving energy density, metals capable of being alloyed with lithium, such as silicon (Si) and tin (Sn), and oxides capable of inserting and extracting lithium ions have been studied as negative electrode materials.
　特許文献１には、リチウムイオンを吸蔵、放出し得る炭素材料粒子、リチウムと合金可能な金属粒子、リチウムイオンを吸蔵、放出し得る酸化物粒子を含む活物質層を備えた二次電池用負極が記載されている。 Patent Document 1 discloses a negative electrode for a secondary battery including an active material layer including carbon material particles capable of inserting and extracting lithium ions, metal particles capable of being alloyed with lithium, and oxide particles capable of inserting and extracting lithium ions. Is described.
　特許文献２には、非水電解質二次電池において、ケイ素の酸化物（特にケイ酸塩）を利用することが記載されている。 Patent Document 2 describes that a silicon oxide (particularly silicate) is used in a non-aqueous electrolyte secondary battery.
　特許文献３には、ケイ素の微結晶がケイ素系化合物に分散した構造を有する粒子の表面を炭素でコーティングした二次電池用負極材料が記載されている。 Patent Document 3 describes a negative electrode material for a secondary battery in which the surface of particles having a structure in which silicon microcrystals are dispersed in a silicon compound is coated with carbon.
　また、充放電サイクル特性等を向上する観点から、負極あるいは負極活物質粒子を重合性化合物を用いて被覆する技術が検討されている。 Also, from the viewpoint of improving charge / discharge cycle characteristics and the like, a technique for coating the negative electrode or the negative electrode active material particles with a polymerizable compound has been studied.
　特許文献４には、ケイ素及び／またはケイ素合金を含む活物質粒子とバインダーとを含む活物質層を導電性金属箔からなる集電体上に配置した後、非酸化性雰囲気下で焼結して得られるリチウム二次電池用負極が記載されている。そして、この負極を用いた二次電池において、非水電解質の溶媒成分としてビニレンカーボネートを添加することで、活物質粒子の表面に、リチウムイオン伝導性の高い皮膜が形成されることが記載されている。 In Patent Document 4, an active material layer containing active material particles containing silicon and / or a silicon alloy and a binder is disposed on a current collector made of a conductive metal foil, and then sintered in a non-oxidizing atmosphere. The negative electrode for lithium secondary batteries obtained is described. And in the secondary battery using this negative electrode, it is described that a film having high lithium ion conductivity is formed on the surface of the active material particles by adding vinylene carbonate as a solvent component of the nonaqueous electrolyte. Yes.
　特許文献５には、リチウムをドープ、脱ドープすることが可能な炭素材料の負極を有する非水電解液電池において、非水電解液が、炭素質負極表面に充電時に被膜を形成するアニオン付加重合性モノマーを含有することが開示されている。 Patent Document 5 discloses an anion addition polymerization in which a nonaqueous electrolyte solution has a carbon material negative electrode capable of being doped and dedoped with lithium, and the nonaqueous electrolyte solution forms a coating on the surface of the carbonaceous negative electrode. Containing a functional monomer.
　特許文献６には、リチウム金属カチオンとキレート化し得る成分が導入されたアニオン重合性モノマーと、リチウム塩と、有機溶媒と、を含む有機電解液を用いたリチウム電池が開示されている。そして、アニオン重合性モノマーは、初期充電時に重合されて炭素系アノード表面に被膜を形成することが記載されている。 Patent Document 6 discloses a lithium battery using an organic electrolytic solution containing an anion polymerizable monomer into which a component capable of chelating with a lithium metal cation is introduced, a lithium salt, and an organic solvent. And it is described that an anion polymerizable monomer is polymerized at the time of initial charge to form a film on the surface of the carbon-based anode.
　特許文献７には、電解酸化重合モノマーと電解還元重合モノマーを含む非水電解液を用いたリチウム二次電池が開示されている。そして、非水電解液に電圧を印加することにより、正極および負極の少なくとも一方に、前記のモノマーが重合してなるポリマーが形成されることが記載されている。 Patent Document 7 discloses a lithium secondary battery using a nonaqueous electrolytic solution containing an electrolytic oxidation polymerization monomer and an electrolytic reduction polymerization monomer. And it is described that by applying a voltage to the non-aqueous electrolyte, a polymer formed by polymerizing the monomer is formed on at least one of the positive electrode and the negative electrode.
　特許文献８には、ポリエチレングリコールジメタクリレート又はポリエチレングリコールジアクリレートからなる重合体に有機電解液が含浸されたポリマー電解質が用いられ、負極の表面に、ポリエチレングリコールジメタクリレート又はポリエチレングリコールジアクリレートとアクリロニトリルとからなる有機質被膜が形成された、リチウム二次電池が開示されている。しかし、充電前に重合開始剤を用いて電解液中でラジカル重合を行いポリマー電解質としていることから、モノマーはラジカル重合で消費され、負極表面への被膜形成は困難であると思われる。また、ポリマー電解質とすることによりイオン伝導性は低下するため、セル特性の悪化が懸念される。実施例の負極は炭素繊維であり、リチウム合金負極へのガス発生抑制効果も不明である。 In Patent Document 8, a polymer electrolyte obtained by impregnating a polymer composed of polyethylene glycol dimethacrylate or polyethylene glycol diacrylate with an organic electrolyte is used. On the surface of the negative electrode, polyethylene glycol dimethacrylate or polyethylene glycol diacrylate and acrylonitrile are used. There is disclosed a lithium secondary battery in which an organic film made of is formed. However, since radical polymerization is performed in an electrolytic solution using a polymerization initiator before charging to obtain a polymer electrolyte, the monomer is consumed by radical polymerization, and it seems difficult to form a film on the negative electrode surface. Moreover, since ion conductivity falls by setting it as a polymer electrolyte, there exists a concern about deterioration of a cell characteristic. The negative electrode of an Example is carbon fiber, and the gas generation | occurrence | production suppression effect to a lithium alloy negative electrode is also unknown.
　特許文献９には、Ｓｉ及び／又はＳｎを含む化合物を主体とする負極活物質が、共役二重結合を含む特定の構造を有する化合物（例えばイソプレン）の重合体で被覆された、非水電解質二次電池が開示されている。 Patent Document 9 discloses a nonaqueous electrolyte in which a negative electrode active material mainly composed of a compound containing Si and / or Sn is coated with a polymer of a compound having a specific structure containing a conjugated double bond (for example, isoprene). A secondary battery is disclosed.
特許３９８２２３０号公報Japanese Patent No. 3982230 特許２９９７７４１号公報Japanese Patent No. 2,997,741 特許３９５２１８０号公報Japanese Patent No. 3952180 特許４０３３７２０号公報Japanese Patent No. 4033720 特許３１６３０７８号公報Japanese Patent No. 3163078 特許４０５０２５１号公報Japanese Patent No. 405251251 特開２００６－２１６２７６号公報JP 2006-216276 A 特開２００２－３２４５７７号公報Japanese Patent Laid-Open No. 2002-324577 特開２００６－２６９４１７号公報JP 2006-269417 A
　リチウムと合金可能な金属を含む負極活物質を用いた二次電池は、充放電サイクルに伴う容量低下が著しく、また保存安定性に劣るという問題があった。リチウムイオンの挿入脱離による負極活物質の体積変化によりヒビ割れ（又は微細化）が発生し、集電体からの剥離や、その体積変化により新たに現れる活性表面での電解液分解によるガス発生、Ｌｉイオン伝導性の低下が起きる。 A secondary battery using a negative electrode active material containing a metal that can be alloyed with lithium has a problem in that the capacity is significantly reduced due to a charge / discharge cycle, and the storage stability is inferior. Cracking (or miniaturization) occurs due to the volume change of the negative electrode active material due to the insertion and removal of lithium ions, and gas generation due to separation from the current collector and decomposition of the electrolyte on the active surface that appears newly due to the volume change Li ion conductivity is reduced.
　本発明の目的は、サイクル特性および保存安定性に優れた非水電解液二次電池を提供することにある。 An object of the present invention is to provide a nonaqueous electrolyte secondary battery excellent in cycle characteristics and storage stability.
　本発明の一態様によれば、正極と、セパレータと、該セパレータを介して該正極と対向配置された負極と、非水電解液と、これらを内包する外装体とを含む、非水電解液二次電池であって、
　前記負極は、リチウムと合金可能な金属（ａ）を含む負極活物質と、結着剤とを含み、
　前記非水電解液は、複数の末端二重結合を有するビニル化合物を含有する、非水電解液二次電池が提供される。 According to one embodiment of the present invention, a non-aqueous electrolyte solution including a positive electrode, a separator, a negative electrode disposed to face the positive electrode with the separator interposed therebetween, a non-aqueous electrolyte solution, and an exterior body that includes them. A secondary battery,
The negative electrode includes a negative electrode active material containing a metal (a) that can be alloyed with lithium, and a binder.
A non-aqueous electrolyte secondary battery is provided in which the non-aqueous electrolyte contains a vinyl compound having a plurality of terminal double bonds.
　本発明の他の態様によれば、正極と、セパレータと、該セパレータを介して該正極と対向配置された負極を含む電極積層体を形成する工程と、
　前記電極積層体を外装体で包む工程と、
　非水電解液を注入する工程とを有し、
　前記負極の形成において、リチウムと合金可能な金属（ａ）を含む負極活物質を使用し、
　前記非水電解液として、複数の末端二重結合を有するビニル化合物を含有する電解液を使用する、非水電解液二次電池の製造方法が提供される。 According to another aspect of the present invention, a step of forming an electrode laminate including a positive electrode, a separator, and a negative electrode disposed to face the positive electrode through the separator;
Wrapping the electrode laminate with an outer package;
A step of injecting a non-aqueous electrolyte,
In forming the negative electrode, using a negative electrode active material containing a metal (a) that can be alloyed with lithium,
Provided is a method for producing a non-aqueous electrolyte secondary battery using an electrolyte containing a vinyl compound having a plurality of terminal double bonds as the non-aqueous electrolyte.
　本発明の実施形態によれば、サイクル特性および保存安定性に優れた非水電解液二次電池を提供できる。 According to the embodiment of the present invention, a non-aqueous electrolyte secondary battery excellent in cycle characteristics and storage stability can be provided.
本発明の実施形態による積層ラミネート型の二次電池の構造を説明するための模式的断面図である。1 is a schematic cross-sectional view for explaining the structure of a laminated laminate type secondary battery according to an embodiment of the present invention.
　以下、本発明の実施形態について、詳細に説明する。 Hereinafter, embodiments of the present invention will be described in detail.
　本発明の実施形態による二次電池は、正極、セパレータ及びこのセパレータを介して正極と対向配置された負極を含む電極積層体と、非水電解液と、これらを内包する外装体とを含む。この負極は、リチウムと合金可能な金属（ａ）を含む負極活物質と、結着剤を含み、この非水電解液は、複数の末端二重結合を有するビニル化合物（以下適宜「多官能ビニル化合物」という）を含有する。この外装体からなる一つの容器内の電極積層体は、正極と負極の電極対を一つ又は二つ以上を含むことができる。本実施形態による二次電池は、このような電極積層体をラミネートフィルムで外装した積層ラミネート型構造を有することができる。 A secondary battery according to an embodiment of the present invention includes a positive electrode, a separator, an electrode laminate including a negative electrode disposed opposite to the positive electrode with the separator interposed therebetween, a non-aqueous electrolyte, and an outer package that contains them. This negative electrode contains a negative electrode active material containing a metal (a) that can be alloyed with lithium and a binder, and this non-aqueous electrolyte comprises a vinyl compound having a plurality of terminal double bonds (hereinafter referred to as “polyfunctional vinyl” as appropriate). Compound)). The electrode laminated body in one container which consists of this exterior body can contain one or two or more electrode pairs of a positive electrode and a negative electrode. The secondary battery according to the present embodiment may have a laminated laminate type structure in which such an electrode laminate is packaged with a laminate film.
　この多官能ビニル化合物は、ラジカル重合またはアニオン重合性能を有することが好ましく、負極に被膜を形成することができる。これにより、サイクル特性および保存安定性を向上することができる。この多官能ビニル化合物において、末端二重結合（末端炭素炭素二重結合）はビニル基（ＣＨ２＝ＣＨ－）に限定されず、例えば２位がメチル基やシアノ基等により置換された置換ビニル基（ＣＨ２＝ＣＸ－、Ｘは置換基）を含む。 This polyfunctional vinyl compound preferably has radical polymerization or anion polymerization performance, and can form a film on the negative electrode. Thereby, cycle characteristics and storage stability can be improved. In this polyfunctional vinyl compound, the terminal double bond (terminal carbon-carbon double bond) is not limited to the vinyl group (CH 2 ═CH—). A group (CH 2 ═CX—, where X is a substituent).
　非水電解液における多官能ビニル化合物の含有率は、十分な添加効果を得る点から、０．０１質量％以上が好ましく、０．１質量％以上がより好ましく、０．５質量％以上がさらに好ましい。多官能ビニル化合物の過剰な添加はコスト増や抵抗上昇を招くため、１０質量％以下が好ましく、５質量％以下がより好ましく、３質量％以下がさらに好ましい。 The content of the polyfunctional vinyl compound in the nonaqueous electrolytic solution is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and further preferably 0.5% by mass or more from the viewpoint of obtaining a sufficient addition effect. preferable. Excessive addition of the polyfunctional vinyl compound causes an increase in cost and an increase in resistance, so it is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less.
　この非水電解液としては、多官能ビニル化合物と非水系溶媒の混合溶液に、支持塩を溶解したものを用いることができる。 As the non-aqueous electrolyte, a solution obtained by dissolving a supporting salt in a mixed solution of a polyfunctional vinyl compound and a non-aqueous solvent can be used.
　この非水電解液を用いた二次電池では、卑な電位にて負極表面で多官能ビニル化合物の電解重合反応が起こり、負極表面に薄いポリマー膜が形成される。このポリマー膜は、リチウム合金負極表面の活性種（たとえばシリコン負極の場合、シリルリチウム、シリルオキシリチウムなど）を開始剤として重合するため、負極表面に選択的に被膜を形成することができ、リチウム合金負極表面の活性種と電解液の反応を抑制することができる。さらに、このビニル化合物は多官能であるため、電解重合により形成したポリマー膜は３次元架橋体となり、高伸縮性、高強度に優れる。従って、リチウム合金負極の体積変化に追従可能となり、負極活物質の微細化を防ぐことができる。ポリマー膜の厚さは多官能ビニル化合物の添加量で制御できるため、リチウムイオン伝導性の高い非常に薄い膜を形成可能である。これに対して、１つの二重結合を含有する（単官能）ビニル化合物のみで得られるポリマー膜は鎖状ポリマーで構成されるため強度は低く、ポリマー膜が電解液に溶けるおそれもある。また、単環能ビニル化合物も多官能ビニル化合物も含まない非水電解液では、負極表面での非水系溶媒の分解反応により皮膜は形成されるものの、得られた皮膜は炭酸リチウムやアルキルリチウムなどの無機化合物や低分子有機化合物であるため脆く、リチウム合金負極の体積変化に追従することが困難である。さらに、リチウムイオンの挿入脱離に伴う活物質の微細化により新たな活性種が出現するため、電解液の反応を十分に抑制することができない。従って、単官能ビニル化合物のみを含む、もしくは単環能ビニル化合物も多官能ビニル化合物も含まない非水電解液を用いた二次電池では、サイクル試験回数が増えるにつれ、負極表面の皮膜は厚くなりすぎて抵抗上昇が生じる。 In the secondary battery using this non-aqueous electrolyte, an electropolymerization reaction of the polyfunctional vinyl compound occurs on the negative electrode surface at a base potential, and a thin polymer film is formed on the negative electrode surface. Since this polymer film is polymerized using an active species on the surface of the lithium alloy negative electrode (for example, silyl lithium, silyloxy lithium, etc. in the case of a silicon negative electrode) as an initiator, a film can be selectively formed on the negative electrode surface. The reaction between the active species on the surface of the alloy negative electrode and the electrolytic solution can be suppressed. Furthermore, since this vinyl compound is polyfunctional, the polymer film formed by electrolytic polymerization becomes a three-dimensional crosslinked body, and is excellent in high stretchability and high strength. Accordingly, it is possible to follow the volume change of the lithium alloy negative electrode, and it is possible to prevent the negative electrode active material from being miniaturized. Since the thickness of the polymer film can be controlled by the amount of the polyfunctional vinyl compound added, a very thin film having high lithium ion conductivity can be formed. On the other hand, a polymer film obtained only from a (monofunctional) vinyl compound containing one double bond is composed of a chain polymer, so that the strength is low, and the polymer film may be dissolved in the electrolytic solution. In addition, in a non-aqueous electrolyte solution containing neither a monocyclic vinyl compound nor a polyfunctional vinyl compound, a film is formed by the decomposition reaction of the non-aqueous solvent on the negative electrode surface, but the obtained film is made of lithium carbonate, alkyl lithium, etc. Inorganic compounds and low molecular weight organic compounds are fragile and difficult to follow the volume change of the lithium alloy negative electrode. Furthermore, new active species appear due to the refinement of the active material that accompanies the insertion / extraction of lithium ions, and thus the reaction of the electrolytic solution cannot be sufficiently suppressed. Therefore, in a secondary battery using a non-aqueous electrolyte containing only a monofunctional vinyl compound or containing neither a monocyclic vinyl compound nor a polyfunctional vinyl compound, the coating on the negative electrode surface becomes thicker as the number of cycle tests increases. Too much resistance rises.
　非水電解液中の多官能ビニル化合物は、その電解重合が、初充電時にリチウム合金負極表面上に発生するアニオンラジカルを開始剤として起こるため、ラジカル重合またはアニオン重合性能を有することが好ましい。特に、アニオン重合性ビニル化合物であれば、リチウム合金負極表面の活性種を開始点として重合させることで、負極表面と化学的に結合した皮膜が形成され安定な皮膜形成が可能となるので、さらに好ましい。 The polyfunctional vinyl compound in the non-aqueous electrolyte preferably has radical polymerization or anion polymerization performance because the electrolytic polymerization occurs using an anion radical generated on the surface of the lithium alloy negative electrode during initial charging as an initiator. In particular, in the case of an anion-polymerizable vinyl compound, a polymer film chemically bonded to the negative electrode surface is formed by polymerizing the active species on the surface of the lithium alloy negative electrode as a starting point, so that a stable film can be formed. preferable.
　このような多官能ビニル化合物は、式（１Ａ）、（１Ｂ）又は（１Ｃ）で示される基本構造を有することが好ましい。式中のＶ１、Ｖ２、Ｖ３及びＶ４はそれぞれ独立に二重結合含有基を示し、Ｘ１は二重結合含有基が結合する連結基を示す。 Such a polyfunctional vinyl compound preferably has a basic structure represented by the formula (1A), (1B) or (1C). In the formula, V 1 , V 2 , V 3 and V 4 each independently represent a double bond-containing group, and X 1 represents a linking group to which the double bond-containing group is bonded.
Figure JPOXMLDOC01-appb-C000001
 　二重結合含有基Ｖ１、Ｖ２、Ｖ３及びＶ４としては、メタクリロイル基（式２）、アクリロイル基（式３）、ビニルフェニル基（式４）、１，３－ブタジエニル基（式５）、シアノアクリロイル基（式６）が挙げられる。二重結合含有基の組み合わせは同じであっても異なっていても良いが、二重結合含有基が全て同じであるビニル化合物が重合反応が均一に進み、より均質な被膜が形成されるため好ましい。
Figure JPOXMLDOC01-appb-C000001
 The double bond-containing groups V 1 , V 2 , V 3 and V 4 include a methacryloyl group (formula 2), an acryloyl group (formula 3), a vinylphenyl group (formula 4), a 1,3-butadienyl group (formula 5 ), A cyanoacryloyl group (formula 6). The combination of the double bond-containing groups may be the same or different, but a vinyl compound having the same double bond-containing group is preferable because the polymerization reaction proceeds uniformly and a more uniform film is formed. .
Figure JPOXMLDOC01-appb-C000002
 　二重結合含有基を連結する連結基Ｘ１は、アルキレン基やシクロアルキレン等の飽和炭化水素の多価基（炭素数は１～１２が好ましい）；エチレンオキシド単位やメチレンオキシド単位などのアルキレンオキシド単位を含むポリエーテル鎖を含む多価基；フルオロアルキレン基等のフッ素化鎖式飽和炭化水素の多価基（炭素数は１～１２が好ましい）；アミド結合を含む多価基；芳香族環から誘導される多価基；カーボネート基；エステル基；シロキサン鎖などが挙げられる。特に、ポリエーテル鎖を含む多価基は、リチウムイオン伝導性が高まるため好ましい。
Figure JPOXMLDOC01-appb-C000002
 The linking group X 1 linking the double bond-containing group is a saturated hydrocarbon polyvalent group such as an alkylene group or cycloalkylene (preferably having 1 to 12 carbon atoms); an alkylene oxide unit such as an ethylene oxide unit or a methylene oxide unit A polyvalent group containing a polyether chain containing; a polyvalent group of a fluorinated chain saturated hydrocarbon such as a fluoroalkylene group (preferably having 1 to 12 carbon atoms); a polyvalent group containing an amide bond; an aromatic ring Induced polyvalent groups; carbonate groups; ester groups; siloxane chains. In particular, a polyvalent group containing a polyether chain is preferable because lithium ion conductivity is increased.
　エーテル結合やアミド結合を持つビニル化合物は、リチウムイオンとの配位によりリチウムイオン伝導性が高まるため好ましい。アルキレン基等の飽和炭化水素構造や、芳香族環、フルオロアルキレン基等のフッ素化炭化水素構造を含むビニル化合物は、負極表面に形成される皮膜に疎水性が付与され、負極表面と電解液との反応を抑制する効果が上がるため好ましい。カーボネート基やエステル基を含むビニル化合物は、電解液との相溶性が向上するため好ましい。エーテル結合やアルキレン基、シロキサン鎖を含むビニル化合物は、伸縮性の高い被膜が形成されるため好ましい。 A vinyl compound having an ether bond or an amide bond is preferable because lithium ion conductivity is increased by coordination with lithium ions. A vinyl compound containing a saturated hydrocarbon structure such as an alkylene group or a fluorinated hydrocarbon structure such as an aromatic ring or a fluoroalkylene group is imparted with hydrophobicity to the film formed on the negative electrode surface. This is preferable because the effect of suppressing the reaction is increased. A vinyl compound containing a carbonate group or an ester group is preferable because compatibility with the electrolytic solution is improved. A vinyl compound containing an ether bond, an alkylene group, or a siloxane chain is preferable because a highly stretchable film is formed.
　多官能ビニル化合物の具体例としては、エチレングリコールジ（メタ）アクリレート、１，３－プロパンジオールジ（メタ）アクリレート、プロピレングリコールジ（メタ）アクリレート、１，４－ブタンジオールジ（メタ）アクリレート、１，３－ブタンジオールジ（メタ）アクリレート、１，２－ブタンジオールジ（メタ）アクリレート、２，３－ブタンジオールジ（メタ）アクリレート、１－メチル－１，３－プロパンジオールジ（メタ）アクリレート、２－メチル－１，３－プロパンジオールジ（メタ）アクリレート、２－メチル－１，２－プロパンジオールジ（メタ）アクリレート、１，５－ペンタンジオールジ（メタ）アクリレート、１，６－ヘキサンジオールジ（メタ）アクリレート、１，９－ノナンジオールジ（メタ）アクリレート、１，１０－デカンジオールジ（メタ）アクリレート、ネオペンチルグリコールジ（メタ）アクリレート、シクロヘキサン－１，４－ジオールジ（メタ）アクリレート、シクロヘキサン－１，４－ジメタノールジ（メタ）アクリレート、ｐ－キシレングリコールジ（メタ）アクリレート、ジエチレングリコールジ（メタ）アクリレート、トリエチレングリコールジ（メタ）アクリレート、テトラエチレングリコールジ（メタ）アクリレート、ポリエチレングリコールジ（メタ）アクリレート、ジプロピレングリコールジ（メタ）アクリレート、トリプロピレングリコールジ（メタ）アクリレート、テトラプロピレングリコールジ（メタ）アクリレート、ポリプロピレングリコールジ（メタ）アクリレート、ポリテトラメチレングリコールジ（メタ）アクリレート、エチレングリコールプロピレングリコール共重合体ジ（メタ）アクリレート、２－ヒドロキシ－３－アクリロイロキシプロピル（メタ）アクリレート、プロポキシ化エトキシ化ビスフェノールＡジ（メタ）アクリレート、エトキシ化ビスフェノールＡジ（メタ）アクリレート、９，９－ビス［４－（２－（メタ）アクリロイルオキシエトキシ）フェニル］フルオレン、プロポキシ化ビスフェノールＡジ（メタ）アクリレート、トリシクロデカンジメタノールジ（メタ）アクリレート、グリセリンジ（メタ）アクリレート、パーフルオロメチルジ（メタ）アクリレート、パーフルオロエチルジ（メタ）アクリレート、パーフルオロエチレングリコールジ（メタ）アクリレート、フェルラ酸変性ジ（メタ）アクリレート等の二官能（メタ）アクリレート類が挙げられる。 Specific examples of the polyfunctional vinyl compound include ethylene glycol di (meth) acrylate, 1,3-propanediol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, 1,2-butanediol di (meth) acrylate, 2,3-butanediol di (meth) acrylate, 1-methyl-1,3-propanediol di (meth) Acrylate, 2-methyl-1,3-propanediol di (meth) acrylate, 2-methyl-1,2-propanediol di (meth) acrylate, 1,5-pentanediol di (meth) acrylate, 1,6- Hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) a Relate, 1,10-decanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, cyclohexane-1,4-diol di (meth) acrylate, cyclohexane-1,4-dimethanol di (meth) acrylate, p-xylene Glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tri Propylene glycol di (meth) acrylate, tetrapropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol Di (meth) acrylate, ethylene glycol propylene glycol copolymer di (meth) acrylate, 2-hydroxy-3-acryloyloxypropyl (meth) acrylate, propoxylated ethoxylated bisphenol A di (meth) acrylate, ethoxylated bisphenol A Di (meth) acrylate, 9,9-bis [4- (2- (meth) acryloyloxyethoxy) phenyl] fluorene, propoxylated bisphenol A di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, glycerin Di (meth) acrylate, perfluoromethyl di (meth) acrylate, perfluoroethyl di (meth) acrylate, perfluoroethylene glycol di (meth) acrylate, ferulic acid modified di (meth) acrylate Bifunctional (meth) acrylates such as cartons.
　さらに、多官能ビニル化合物の具体例として、トリメチロールプロパントリ（メタ）アクリレート、ジトリメチロールプロパンテトラ（メタ）アクリレート、グリセリントリ（メタ）アクリレート、エトキシ化グリセリントリ（メタ）アクリレート、トリメチロールプロパントリ（メタ）アクリレート、ＥＯ変性トリメチロールプロパントリ（メタ）アクリレート、ＰＯ変性トリメチロールプロパントリ（メタ）アクリレート、ＥＯ／ＰＯ変性トリメチロールプロパントリ（メタ）アクリレート、ひまし油変性トリ（メタ）アクリレート、エトキシ化イソシアヌル酸トリアクリレート、ε－カプロラクトン変性トリス－（２－アクリロキシエチル）イソシアヌレート、ペンタエリスリトールトリ（メタ）アクリレート、エトキシ化ペンタエリスリトールテトラ（メタ）アクリレート、ペンタエリスリトールテトラ（メタ）アクリレート、ジペンタエリスリトールへキサ（メタ）アクリレート、ジペンタエリスリトールポリアクリレート、エトキシ化ｐ－ｔ－ブチルカリックスアレーンポリ（メタ）アクリレート等の多官能（メタ）アクリレート類が挙げられる。 Furthermore, specific examples of the polyfunctional vinyl compound include trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, glycerin tri (meth) acrylate, ethoxylated glycerin tri (meth) acrylate, trimethylolpropane tri ( (Meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, PO-modified trimethylolpropane tri (meth) acrylate, EO / PO-modified trimethylolpropane tri (meth) acrylate, castor oil-modified tri (meth) acrylate, ethoxylated isocyanuric Acid triacrylate, ε-caprolactone modified tris- (2-acryloxyethyl) isocyanurate, pentaerythritol tri (meth) acrylate, ethoxylated pentae Multifunctional such as sitolitol tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol polyacrylate, ethoxylated pt-butylcalixarene poly (meth) acrylate (Meth) acrylates may be mentioned.
　さらに、多官能ビニル化合物の具体例として、ブタジエン、イソプレン等の共役ジエン類、ジビニルベンゼン、１，２，４－トリビニルベンゼン、１，３，５－トリビニルベンゼン、ジビニルナフタレンなどの多官能芳香族ビニル化合物が挙げられる。 Furthermore, specific examples of the polyfunctional vinyl compound include conjugated dienes such as butadiene and isoprene, polyfunctional fragrances such as divinylbenzene, 1,2,4-trivinylbenzene, 1,3,5-trivinylbenzene, and divinylnaphthalene. Group vinyl compounds.
　また、多官能ビニル化合物は、ビニル基を有する塩化物（塩化アクリロイル、塩化メタクリロイル、クロロメチルスチレンなど）と水酸基を複数有するポリオールとの反応により、合成することができる。２つ以上の水酸基を有するポリオールとして、例えば、エチレングリコール、プロピレングリコール、ジプロピレングリコール、１，３－および１，４－ブタンジオール、１，６－ヘキサンジオールなどの２価アルコール、グリセリン、トリメチロールプロパン、トリメチロールエタン、ヘキサントリオールなどの３価アルコール、ペンタエリスリトール、メチルグリコシド、ジグリセリンなどの４価アルコール、トリグリセリン、テトラグリセリンなどのポリグリセリン、ジペンタエリスリトール、トリペンタエリスリトールなどのポリペンタエリスリトール、テトラキス（ヒドロキシメチル）シクロヘキサノールなどのシクロアルカンポリオール、ポリビニルアルコールが挙げられる。また、アドニトール、アラビトール、キシリトール、ソルビトール、マンニトール、イジトール、タリトール、ズルシトールなどの糖アルコール、グルコース、マンノースグルコース、マンノース、フラクトース、ソルボース、スクロース、ラクトース、ラフィノース、セルロースなどの糖類が挙げられる。多価フェノールとしてはピロガロール，ハイドロキノン，フロログルシンなどの単環多価フェノール、ビスフェノールＡ、ビスフェノールスルフォンなどのビスフェノール類、フェノールとホルムアルデヒドの縮合物（ノボラック）などが挙げられる。 In addition, the polyfunctional vinyl compound can be synthesized by a reaction between a chloride having a vinyl group (acryloyl chloride, methacryloyl chloride, chloromethylstyrene, etc.) and a polyol having a plurality of hydroxyl groups. Examples of polyols having two or more hydroxyl groups include dihydric alcohols such as ethylene glycol, propylene glycol, dipropylene glycol, 1,3- and 1,4-butanediol, and 1,6-hexanediol, glycerin, and trimethylol. Trivalent alcohols such as propane, trimethylolethane and hexanetriol, tetrahydric alcohols such as pentaerythritol, methylglycoside and diglycerin, polyglycerin such as triglycerin and tetraglycerin, polypentaerythritol such as dipentaerythritol and tripentaerythritol , Cycloalkane polyols such as tetrakis (hydroxymethyl) cyclohexanol, and polyvinyl alcohol. In addition, sugar alcohols such as adonitol, arabitol, xylitol, sorbitol, mannitol, iditol, tallitol, dulcitol, and sugars such as glucose, mannose glucose, mannose, fructose, sorbose, sucrose, lactose, raffinose, and cellulose can be used. Examples of the polyhydric phenol include monocyclic polyhydric phenols such as pyrogallol, hydroquinone and phloroglucin, bisphenols such as bisphenol A and bisphenol sulfone, and phenol / formaldehyde condensates (novolaks).
　このような多官能ビニル化合物を用いることで、リチウム合金負極表面での電解重合反応により形成されるポリマー膜は３次元架橋体となり、伸縮性や強度に優れる皮膜が形成できる。多官能ビニル化合物は、一種を単独で、または二種以上を組み合わせて使用することができる。 By using such a polyfunctional vinyl compound, the polymer film formed by the electrolytic polymerization reaction on the surface of the lithium alloy negative electrode becomes a three-dimensional crosslinked body, and a film excellent in stretchability and strength can be formed. A polyfunctional vinyl compound can be used individually by 1 type or in combination of 2 or more types.
　多官能ビニル化合物による所望の効果を阻害しない範囲で、多官能ビニル化合物と単官能ビニル化合物とを混合して用いてもよい。 A mixture of a polyfunctional vinyl compound and a monofunctional vinyl compound may be used as long as the desired effect of the polyfunctional vinyl compound is not impaired.
　単官能ビニル化合物の具体例としては、メチル（メタ）アクリレート、エチル（メタ）アクリレート、プロピル（メタ）アクリレート、イソプロピル（メタ）アクリレート、ブチル（メタ）アクリレート、イソブチル（メタ）アクリレート、ｓｅｃ－ブチル（メタ）アクリレート、ｔ－ブチル（メタ）アクリレート、２－エチルヘキシル（メタ）アクリレート、シクロヘキシル（メタ）アクリレート、メトキシエチル（メタ）アクリレート、メトキシポリエチレングリコール（メタ）アクリレート、Ｎ，Ｎ－ジメチルアミノエチル（メタ）アクリレート、イソボルニル（メタ）アクリレート、エトキシ化ｏ－フェニルフェノール（メタ）アクリレート、メトキシポリエチレングリコール（メタ）アクリレート、フェノキシポリエチレングリコール（メタ）アクリレート、イソステアリル（メタ）アクリレート、２－（メタ）アクリロイルオキシエチルサクシネート、２－（メタ）アクリロイロキシエチルフタル酸、フェノキシエチレングリコール（メタ）アクリレート、ステアリル（メタ）アクリレート、２－（メタ）アクリロイルオキシエチルサクシネート等のメタクリル酸エステル誘導体、アクリル酸エステル誘導体が挙げられる。 Specific examples of the monofunctional vinyl compound include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl ( (Meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, methoxyethyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, N, N-dimethylaminoethyl (meth) ) Acrylate, isobornyl (meth) acrylate, ethoxylated o-phenylphenol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, phenoxypolyethyleneglycol (Meth) acrylate, isostearyl (meth) acrylate, 2- (meth) acryloyloxyethyl succinate, 2- (meth) acryloyloxyethylphthalic acid, phenoxyethylene glycol (meth) acrylate, stearyl (meth) acrylate , Methacrylic acid ester derivatives such as 2- (meth) acryloyloxyethyl succinate, and acrylic acid ester derivatives.
　さらに、単官能ビニル化合物の具体例としては、スチレン、ビニルトルエン、α－メチルスチレン、ビニルナフタレン等の芳香族ビニル類、エチレン、プロピレン、１－ブテン、イソブテン、１－ペンテン、３－メチル－１－ブテン、４－メチル－１－ペンテン、１－ヘキセン、ビニルシクロヘキサン、シクロブテン、シクロペンテン、シクロヘキセン等のアルケン類が挙げられる。 Further, specific examples of the monofunctional vinyl compound include aromatic vinyls such as styrene, vinyl toluene, α-methyl styrene, vinyl naphthalene, ethylene, propylene, 1-butene, isobutene, 1-pentene, 3-methyl-1 Alkenes such as -butene, 4-methyl-1-pentene, 1-hexene, vinylcyclohexane, cyclobutene, cyclopentene, cyclohexene and the like can be mentioned.
　また、多官能ビニル化合物とビニレンカーボネートを併用した非水電解液も用いることができる。この非水電解液を用いた二次電池では、卑な電位にて負極表面でビニレンカーボネートの分解反応が起こり、負極表面にビニレンカーボネート分解物の膜が形成される。この膜には、ビニレンカーボネート由来の二重結合が残存し、この二重結合が多官能ビニル化合物のビニル基と反応するため、分解物の膜は架橋構造を形成するため、ビニレンカーボネート単独よりも強固な膜となり、リチウム合金負極表面の活性種と電解液の反応を抑制することができる。さらに、この膜は三次元架橋体であるため、高伸縮性、高強度に優れる。従って、リチウム合金負極の体積変化に追従可能となり、負極活物質の微細化を防ぐことができる。膜の厚さはビニレンカーボネートおよび多官能ビニル化合物の添加量で制御できるため、リチウムイオン伝導性の高い非常に薄い膜を形成可能である。ビニレンカーボネートのみの非水電解液では、負極表面での非水系溶媒の分解反応により被膜は形成されるものの、得られた被膜は脆く、リチウム合金負極の体積変化に追従することが困難である。さらに、リチウムイオンの挿入脱離に伴う活物質の微細化により新たな活性種が出現するため、電解液の反応を十分に抑制することができない。従って、ビニレンカーボネートのみの非水電解液を用いた二次電池では、サイクル試験回数が増えるにつれ、負極表面の被膜は厚くなりすぎて抵抗上昇が生じる。 In addition, a non-aqueous electrolyte using a polyfunctional vinyl compound and vinylene carbonate can also be used. In the secondary battery using this non-aqueous electrolyte, the decomposition reaction of vinylene carbonate occurs on the negative electrode surface at a base potential, and a film of vinylene carbonate decomposition product is formed on the negative electrode surface. In this film, a double bond derived from vinylene carbonate remains, and this double bond reacts with the vinyl group of the polyfunctional vinyl compound, so that the decomposition product film forms a cross-linked structure. It becomes a strong film and can suppress the reaction between the active species on the surface of the lithium alloy negative electrode and the electrolytic solution. Furthermore, since this film is a three-dimensional crosslinked body, it is excellent in high stretchability and high strength. Accordingly, it is possible to follow the volume change of the lithium alloy negative electrode, and it is possible to prevent the negative electrode active material from being miniaturized. Since the thickness of the film can be controlled by the amount of vinylene carbonate and polyfunctional vinyl compound added, a very thin film having high lithium ion conductivity can be formed. In a non-aqueous electrolyte solution containing only vinylene carbonate, a coating film is formed by the decomposition reaction of the non-aqueous solvent on the negative electrode surface, but the obtained coating film is brittle and it is difficult to follow the volume change of the lithium alloy negative electrode. Furthermore, new active species appear due to the refinement of the active material that accompanies the insertion / extraction of lithium ions, and thus the reaction of the electrolytic solution cannot be sufficiently suppressed. Therefore, in a secondary battery using a non-aqueous electrolyte containing only vinylene carbonate, as the number of cycle tests increases, the coating on the negative electrode surface becomes too thick and resistance increases.
　非水電解液におけるビニル化合物の含有量は、多いほど負極表面での非水系電解液の分解反応を抑制することができる。これは、ガス発生抑制効果で検証される。一方、少ないほど、電極表面に形成される皮膜が薄くなるため抵抗上昇を抑えることができ、出力特性の向上や低コスト化が可能となる。上記の観点から、非水系溶媒に対してビニル化合物の添加量は０．０１～１０質量％の範囲に設定することができ、より十分な添加効果を得る点から０．１質量％以上が好ましく、０．５質量％以上がさらに好ましく、また、所望の効果が得られる範囲で５質量％以下が好ましく、３質量％以下がより好ましく、２質量％以下に設定することもできる。 As the vinyl compound content in the non-aqueous electrolyte increases, the decomposition reaction of the non-aqueous electrolyte on the negative electrode surface can be suppressed. This is verified by the gas generation suppression effect. On the other hand, the smaller the thickness, the thinner the film formed on the electrode surface, so that the increase in resistance can be suppressed, and the output characteristics can be improved and the cost can be reduced. From the above viewpoint, the addition amount of the vinyl compound with respect to the non-aqueous solvent can be set in a range of 0.01 to 10% by mass, and is preferably 0.1% by mass or more from the viewpoint of obtaining a sufficient addition effect. 0.5 mass% or more is more preferable, and 5 mass% or less is preferable in the range in which a desired effect is acquired, 3 mass% or less is more preferable, and it can also set to 2 mass% or less.
　また、非水電解液におけるビニレンカーボネートおよび多官能ビニル化合物の含有量についても、上記の観点から、非水電解液におけるビニレンカーボネートおよび多官能ビニル化合物の含有率は、それぞれ０．０１質量％以上が好ましく、０．１質量％以上がより好ましく、０．５質量％以上がさらに好ましく、また、５質量％以下が好ましく、３質量％以下がより好ましく、１質量％以下がさらに好ましい。ビニレンカーボネートおよび多官能ビニル化合物をあわせた含有率は、０．１質量％以上が好ましく、０．５質量％以上がより好ましく、１質量％以上がさらに好ましく、また、１０質量％以下が好ましく、５質量％以下がより好ましく、３質量％以下がさらに好ましい。 Moreover, also about content of vinylene carbonate and a polyfunctional vinyl compound in a non-aqueous electrolyte, from said viewpoint, the content rate of vinylene carbonate and a polyfunctional vinyl compound in a non-aqueous electrolyte is 0.01 mass% or more, respectively. Preferably, 0.1 mass% or more is more preferable, 0.5 mass% or more is more preferable, 5 mass% or less is preferable, 3 mass% or less is more preferable, and 1 mass% or less is further preferable. The total content of vinylene carbonate and polyfunctional vinyl compound is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, further preferably 1% by mass or more, and preferably 10% by mass or less, 5 mass% or less is more preferable, and 3 mass% or less is further more preferable.
　単官能ビニル化合物と多官能ビニル化合物を併用する場合、及びビニレンカーボネートと単官能ビニル化合物と多官能ビニル化合物とを併用する場合は、これらの合計量に対して単官能ビニル化合物の含有比率は、７０質量％以下が好ましく、６０質量％以下がより好ましく、５０質量％以下がさらに好ましい。 When a monofunctional vinyl compound and a polyfunctional vinyl compound are used in combination, and when vinylene carbonate, a monofunctional vinyl compound and a polyfunctional vinyl compound are used in combination, the content ratio of the monofunctional vinyl compound relative to the total amount of these is 70 mass% or less is preferable, 60 mass% or less is more preferable, and 50 mass% or less is further more preferable.
　非水系溶媒は、非水電解液の溶媒として通常使用されるものを用いることができる。その具体例としては、カーボネート類、塩素化炭化水素、エーテル類、ケトン類、エステル類、ニトリル類等が挙げられる。例えば、エチレンカーボネート（ＥＣ）、プロピレンカーボネート（ＰＣ）、γ－ブチロラクトン（ＧＢＬ）、およびそれらをフッ素置換したもの等の高誘電率の非水系溶媒から選ばれる少なくとも一種と、ジエチルカーボネート（ＤＥＣ）、ジメチルカーボネート（ＤＭＣ）、エチルメチルカーボネート（ＥＭＣ）、γ－ブチロラクトン以外のエステル類、エーテル類、およびそれらをフッ素置換したもの等の低誘電率の非水系溶媒から選ばれる少なくとも一種とを混合して用いることができる。 As the non-aqueous solvent, those usually used as the solvent for the non-aqueous electrolyte can be used. Specific examples thereof include carbonates, chlorinated hydrocarbons, ethers, ketones, esters, and nitriles. For example, at least one selected from non-aqueous solvents having a high dielectric constant such as ethylene carbonate (EC), propylene carbonate (PC), γ-butyrolactone (GBL), and those obtained by fluorine substitution thereof, diethyl carbonate (DEC), Mixing at least one selected from non-aqueous solvents having a low dielectric constant such as dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), esters other than γ-butyrolactone, ethers, and those obtained by fluorine substitution thereof Can be used.
　支持塩としては、ＬｉＰＦ６、ＬｉＡｓＦ６、ＬｉＡｌＣｌ４、ＬｉＣｌＯ４、ＬｉＢＦ４、ＬｉＳｂＦ６、ＬｉＣＦ３ＳＯ３、ＬｉＣ４Ｆ９ＳＯ３、Ｌｉ（ＣＦ３ＳＯ２）２、ＬｉＮ（ＣＦ３ＳＯ２）２等のリチウム塩が挙げられる。支持塩は、一種を単独で、または二種以上を組み合わせて使用することができる。 Examples of the supporting salt include LiPF 6 , LiAsF 6 , LiAlCl 4 , LiClO 4 , LiBF 4 , LiSbF 6 , LiCF 3 SO 3 , LiC 4 F 9 SO 3 , Li (CF 3 SO 2 ) 2 , LiN (CF 3 SO 2 ) A lithium salt such as 2 . The supporting salt can be used alone or in combination of two or more.
　上記の非水電解液は、特定の負極、すなわち、負極活物質として、リチウムと合金可能な金属（ａ）を用いた場合に効果的であり、特に、金属（ａ）と、リチウムイオンを吸蔵放出し得る金属酸化物（ｂ）と、リチウムイオンを吸蔵放出し得る炭素材料（ｃ）とを用いた場合にさらに効果的である。 The non-aqueous electrolyte is effective when a metal (a) that can be alloyed with lithium is used as a specific negative electrode, that is, a negative electrode active material, and in particular, occludes the metal (a) and lithium ions. It is more effective when the metal oxide (b) that can be released and the carbon material (c) that can occlude and release lithium ions are used.
　本実施形態による非水電解液二次電池の形状は、円筒型、扁平捲回角型、積層角型、コイン型、扁平捲回ラミネート型、および積層ラミネート型が挙げられる。後述の観点から、積層ラミネート型が好ましい。 The shape of the non-aqueous electrolyte secondary battery according to the present embodiment includes a cylindrical shape, a flat wound rectangular shape, a laminated rectangular shape, a coin shape, a flat wound laminated shape, and a laminated laminated shape. From the viewpoint described later, a laminated laminate type is preferable.
　図１は、積層ラミネート型の非水電解液二次電池の電極積層体の一例を示す模式的断面図である。図１においては、外装体を省略している。正極３と負極１は、セパレータ２を介して交互に積み重ねられている。各正極３が有する正極集電体５は、正極活物質に覆われていない端部で互いに溶接されて電気的に接続され、さらにその溶接箇所に正極端子６が溶接されている。各負極１が有する負極集電体４は、負極活物質に覆われていない端部で互いに溶接されて電気的に接続され、さらにその溶接箇所に負極端子７が溶接されている。この電極積層体は、外装体としてラミネートフィルムで形成した容器内に収容され、電解液が注入され、シールされる。 FIG. 1 is a schematic cross-sectional view showing an example of an electrode laminate of a laminated laminate type nonaqueous electrolyte secondary battery. In FIG. 1, the exterior body is omitted. The positive electrode 3 and the negative electrode 1 are alternately stacked via the separator 2. The positive electrode current collector 5 of each positive electrode 3 is welded to and electrically connected to each other at an end portion not covered with the positive electrode active material, and the positive electrode terminal 6 is welded to the welded portion. A negative electrode current collector 4 included in each negative electrode 1 is welded to and electrically connected to each other at an end portion not covered with the negative electrode active material, and a negative electrode terminal 7 is welded to the welded portion. This electrode laminate is housed in a container formed of a laminate film as an exterior body, and an electrolyte is injected and sealed.
　このような平面的な積層構造を有する積層型の電池（積層ラミネート型電池）は、捲回構造を有する電池（捲回型電池）に対して、Ｒの小さい部分（例えば捲回構造の巻き芯に近い領域や、扁平捲回構造の折り返し領域）が存在しないため、充放電に伴う電極の体積変化による悪影響を受けにくいという利点がある。一方、捲回型電池では電極が湾曲しているため、電極に体積変化が生じた場合にその構造が歪みやすい。このような歪みは、特に、ケイ素系活物質のように充放電に伴う体積変化が大きい負極活物質を用いた場合に顕著である。このように、捲回型電池と比較して、積層ラミネート型電池は、充放電に伴う体積変化が大きい活物質を用いる場合に適している。なお、「平面的な積層構造」とは、積層された各電極がシート状物であり、各電極が平面状のまま積層配置（シート状物の外周縁が積層構造の周端部にあるように配置）されていることを意味し、電極積層体が折り曲げられた構造や、電極積層体が捲き回された構造と区別される。 A laminated battery (laminated laminated battery) having such a planar laminated structure has a smaller R portion (for example, a wound core with a wound structure) than a battery having a wound structure (winded battery). Therefore, there is an advantage that it is difficult to be adversely affected by the volume change of the electrode accompanying charging / discharging. On the other hand, since the electrode is curved in the wound type battery, the structure is easily distorted when a volume change occurs in the electrode. Such distortion is particularly noticeable when a negative electrode active material having a large volume change associated with charge / discharge, such as a silicon-based active material, is used. Thus, as compared with a wound battery, a laminated laminate battery is suitable when an active material having a large volume change associated with charge / discharge is used. In addition, “planar laminated structure” means that each laminated electrode is a sheet-like material, and each electrode is laminated in a planar shape (the outer peripheral edge of the sheet-like material is at the peripheral edge of the laminated structure) It is distinguished from a structure in which the electrode stack is bent or a structure in which the electrode stack is wound.
　しかしながら、このような積層ラミネート型電池は、電極間にガスが発生した際に、その発生したガスが電極間に滞留しやすい問題がある。これは、捲回型電池では電極に張力が働いているため電極間の間隔が広がりにくいのに対して、積層ラミネート型電池では電極間の間隔が広がりやすいためである。外装体がアルミニウムラミネートフィルムである場合、この問題は特に顕著となる。さらに、電解液が炭酸エステル溶媒やカルボン酸エステル溶媒を含む場合、この問題がより一層顕著となる。 However, such a laminated laminate type battery has a problem that when the gas is generated between the electrodes, the generated gas tends to stay between the electrodes. This is because in the wound battery, the distance between the electrodes is difficult to increase because tension is applied to the electrodes, whereas in the laminated laminate battery, the distance between the electrodes is likely to increase. This problem is particularly noticeable when the outer package is an aluminum laminate film. Further, when the electrolytic solution contains a carbonate ester solvent or a carboxylic acid ester solvent, this problem becomes even more remarkable.
　本実施形態によれば、ガスを発生させやすい高エネルギー型の負極を用いた積層ラミネート型の非水電解液二次電池においても、長寿命駆動を行うことができる。 According to the present embodiment, a long-life drive can be performed even in a laminated non-aqueous electrolyte secondary battery using a high energy negative electrode that easily generates gas.
　以下、本実施形態による非水電解液二次電池の構成要素についてさらに説明する。 Hereinafter, the components of the non-aqueous electrolyte secondary battery according to the present embodiment will be further described.
　［１］負極
　本実施形態における負極は、集電体と、この集電上の活物質層とを含み、この活物質層は、結着剤と負極活物質を含む。結着剤によって、活物質粒子間、活物質粒子と集電体間が結着される。 [1] Negative Electrode The negative electrode in the present embodiment includes a current collector and an active material layer on the current collector, and the active material layer includes a binder and a negative electrode active material. The binder binds between the active material particles and between the active material particles and the current collector.
　本実施形態における負極活物質は、リチウムと合金可能な金属（ａ）を含み、さらに、リチウムイオンを吸蔵放出し得る金属酸化物（ｂ）を含んでいることが好ましく、さらにリチウムイオンを吸蔵放出し得る炭素材料（ｃ）を含んでいることがより好ましい。 The negative electrode active material in the present embodiment includes a metal (a) that can be alloyed with lithium, and further preferably includes a metal oxide (b) that can occlude and release lithium ions, and further occludes and releases lithium ions. It is more preferable that the carbon material (c) which can be obtained is included.
　金属（ａ）としては、Ａｌ、Ｓｉ、Ｐｂ、Ｓｎ、Ｉｎ、Ｂｉ、Ａｇ、Ｂａ、Ｃａ、Ｈｇ、Ｐｄ、Ｐｔ、Ｔｅ、Ｚｎ、Ｌａ、またはこれらの２種以上を含む合金を用いることができる。特に、金属（ａ）としてシリコン（Ｓｉ）又はシリコン含有金属が好ましく、シリコンがより好ましい。 As the metal (a), Al, Si, Pb, Sn, In, Bi, Ag, Ba, Ca, Hg, Pd, Pt, Te, Zn, La, or an alloy containing two or more of these is used. it can. In particular, silicon (Si) or a silicon-containing metal is preferable as the metal (a), and silicon is more preferable.
　金属酸化物（ｂ）としては、酸化シリコン、酸化アルミニウム、酸化スズ、酸化インジウム、酸化亜鉛、酸化リチウム、またはこれらの二種以上を含む複合酸化物を用いることができる。特に、金属酸化物（ｂ）として酸化シリコンを含むことが好ましい。これは、酸化シリコンは、比較的安定で他の化合物との反応を起こしにくいからである。また、金属酸化物（ｂ）に、窒素、ホウ素およびイオウから選ばれる一種または二種以上の元素を、例えば０．１～５質量％添加することもできる。こうすることで、金属酸化物（ｂ）の電気伝導性を向上させることができる。 As the metal oxide (b), silicon oxide, aluminum oxide, tin oxide, indium oxide, zinc oxide, lithium oxide, or a composite oxide containing two or more of these can be used. In particular, silicon oxide is preferably included as the metal oxide (b). This is because silicon oxide is relatively stable and does not easily react with other compounds. In addition, one or more elements selected from nitrogen, boron and sulfur may be added to the metal oxide (b), for example, 0.1 to 5% by mass. By carrying out like this, the electrical conductivity of a metal oxide (b) can be improved.
　金属酸化物（ｂ）は、その全部または一部がアモルファス構造を有することが好ましい。アモルファス構造の金属酸化物（ｂ）は、他の負極活物質成分である炭素材料（ｃ）や金属（ａ）の体積膨張を抑制でき、また非水電解液の分解を抑制できる。このメカニズムは明確ではないが、金属酸化物（ｂ）がアモルファス構造であることにより、炭素材料（ｃ）と非水電解液の界面への皮膜形成に何らかの影響があるものと推測される。また、アモルファス構造は、結晶粒界や欠陥といった不均一性に起因する要素が比較的少ないと考えられる。なお、金属酸化物（ｂ）の全部または一部がアモルファス構造を有することは、エックス線回折測定（一般的なＸＲＤ測定）にて確認することができる。具体的には、金属酸化物（ｂ）がアモルファス構造を有しない場合には、金属酸化物（ｂ）に固有のピークが観測されるが、金属酸化物（ｂ）の全部または一部がアモルファス構造を有する場合は、金属酸化物（ｂ）に固有のピークがブロードとなって観測される。 The metal oxide (b) preferably has an amorphous structure in whole or in part. The metal oxide (b) having an amorphous structure can suppress the volume expansion of the carbon material (c) and the metal (a), which are other negative electrode active material components, and can suppress the decomposition of the nonaqueous electrolytic solution. Although this mechanism is not clear, it is presumed that the metal oxide (b) has an amorphous structure, so that there is some influence on the film formation at the interface between the carbon material (c) and the non-aqueous electrolyte. The amorphous structure is considered to have relatively few elements due to non-uniformity such as crystal grain boundaries and defects. It can be confirmed by X-ray diffraction measurement (general XRD measurement) that all or part of the metal oxide (b) has an amorphous structure. Specifically, when the metal oxide (b) does not have an amorphous structure, a peak specific to the metal oxide (b) is observed, but all or part of the metal oxide (b) is amorphous. When it has a structure, a peak specific to the metal oxide (b) is observed as a broad.
　負極活物質が金属（ａ）および金属酸化物（ｂ）を含む場合、金属（ａ）は、その全部または一部が金属酸化物（ｂ）中に分散していることが好ましい。金属（ａ）の少なくとも一部を金属酸化物（ｂ）中に分散させることで、負極全体としての体積膨張をより抑制することができ、非水電解液の分解も抑制することができる。なお、金属（ａ）の全部または一部が金属酸化物（ｂ）中に分散していることは、透過型電子顕微鏡観察（一般的なＴＥＭ観察）とエネルギー分散型Ｘ線分光法測定（一般的なＥＤＸ測定）を併用することで確認することができる。具体的には、金属（ａ）を含むサンプルの断面を観察し、金属酸化物（ｂ）中に分散している粒子の酸素濃度を測定し、その粒子を構成している金属（ａ）が酸化物となっていないことを確認することができる。 When the negative electrode active material contains a metal (a) and a metal oxide (b), it is preferable that the metal (a) is entirely or partially dispersed in the metal oxide (b). By dispersing at least a part of the metal (a) in the metal oxide (b), the volume expansion of the whole negative electrode can be further suppressed, and the decomposition of the non-aqueous electrolyte can also be suppressed. Note that all or part of the metal (a) is dispersed in the metal oxide (b) because of observation with a transmission electron microscope (general TEM observation) and energy dispersive X-ray spectroscopy (general). This can be confirmed by using a combination of a standard EDX measurement. Specifically, the cross section of the sample containing the metal (a) is observed, the oxygen concentration of the particles dispersed in the metal oxide (b) is measured, and the metal (a) constituting the particles is It can be confirmed that it is not an oxide.
　負極活物質が金属（ａ）および金属酸化物（ｂ）を含む場合、金属酸化物（ｂ）は、金属（ａ）を構成する金属の酸化物であることが好ましい。金属（ａ）が単体シリコンであり、金属酸化物（ｂ）が酸化シリコンであることがより好ましい。 When the negative electrode active material contains a metal (a) and a metal oxide (b), the metal oxide (b) is preferably an oxide of a metal constituting the metal (a). More preferably, the metal (a) is simple silicon and the metal oxide (b) is silicon oxide.
　金属（ａ）と金属酸化物（ｂ）を含む負極活物質は、例えば、金属（ａ）と金属酸化物（ｂ）を高温減圧下で焼結させることにより得ることができる。あるいは、金属（ａ）と金属酸化物（ｂ）をメカニカルミリングで混合することで得ることができる。このようにして形成された活物質は、炭素で被覆することができる。例えば、この活物質と有機化合物とを混合し焼成する方法や、メタン等の有機化合物のガス雰囲気下にこの活物質を導入し、熱ＣＶＤを行う方法がある。 The negative electrode active material containing metal (a) and metal oxide (b) can be obtained, for example, by sintering metal (a) and metal oxide (b) under high temperature and reduced pressure. Or it can obtain by mixing a metal (a) and a metal oxide (b) by mechanical milling. The active material thus formed can be coated with carbon. For example, there are a method of mixing and baking this active material and an organic compound, and a method of introducing this active material into a gas atmosphere of an organic compound such as methane and performing thermal CVD.
　炭素材料（ｃ）としては、黒鉛、非晶質炭素、ダイヤモンド状炭素、カーボンナノチューブ、またはこれらの二種以上を含む複合物を用いることができる。ここで、結晶性の高い黒鉛は、電気伝導性が高く、銅などの金属からなる正極集電体との接着性および電圧平坦性が優れている。そのため、高出力・高エネルギーの二次電池を設計する点で有利である。一方、結晶性の低い非晶質炭素は、体積膨張が比較的小さいため、負極全体の体積膨張を緩和する効果が高く、かつ結晶粒界や欠陥といった不均一性に起因する劣化が起きにくい。そのため、長寿命・高ロバスト性の二次電池を設計する点で有利である。 As the carbon material (c), graphite, amorphous carbon, diamond-like carbon, carbon nanotube, or a composite containing two or more of these can be used. Here, graphite with high crystallinity has high electrical conductivity, and is excellent in adhesiveness and voltage flatness with a positive electrode current collector made of a metal such as copper. Therefore, it is advantageous in designing a secondary battery with high output and high energy. On the other hand, since amorphous carbon having low crystallinity has a relatively small volume expansion, it has a high effect of relaxing the volume expansion of the entire negative electrode, and deterioration due to non-uniformity such as crystal grain boundaries and defects hardly occurs. Therefore, it is advantageous in designing a secondary battery having a long life and high robustness.
　金属（ａ）と金属酸化物（ｂ）、炭素材料（ｃ）の複合体である負極活物質としては、金属酸化物（ｂ）の全部または一部がアモルファス構造であり、金属（ａ）の全部または一部が金属酸化物（ｂ）中に分散しているものを用いることができる。このような負極活物質は、例えば、特許文献３（特開２００４－４７４０４号公報）に記載されている方法で作製することができる。例えば、金属酸化物（ｂ）をメタンガスなどの有機化合物のガスを含む雰囲気下、９００～１４００℃で不均化するとともに熱ＣＶＤ処理を行う。これにより、金属酸化物（ｂ）中の金属元素が金属（ａ）としてナノクラスター化し、かつ表面が炭素材料（ｃ）で被覆された複合体を得ることができる。この複合体を負極活物質として用いることができる。 As the negative electrode active material that is a composite of the metal (a), the metal oxide (b), and the carbon material (c), all or part of the metal oxide (b) has an amorphous structure, and the metal (a) What disperse | distributes all or one part in a metal oxide (b) can be used. Such a negative electrode active material can be produced, for example, by the method described in Patent Document 3 (Japanese Patent Laid-Open No. 2004-47404). For example, the metal oxide (b) is disproportionated at 900 to 1400 ° C. in an atmosphere containing an organic compound gas such as methane gas and a thermal CVD process is performed. Thereby, the metal element in metal oxide (b) can be clustered as a metal (a), and the composite body by which the surface was coat | covered with the carbon material (c) can be obtained. This composite can be used as a negative electrode active material.
　金属（ａ）と金属酸化物（ｂ）と炭素材料（ｃ）とを含む負極活物質は、メカニカルミリングで混合することでも、作製することができる。 The negative electrode active material containing the metal (a), the metal oxide (b), and the carbon material (c) can also be produced by mixing by mechanical milling.
　負極活物質中の金属（ａ）の含有率は、十分な添加効果（充放電容量等）を得る点から５質量％以上が好ましく、１０質量％以上がより好ましく、２０質量％以上がさらに好ましく、他の成分の添加効果等を十分に得る点から、９５質量％以下が好ましく、９０質量％以下がより好ましく、８０質量％以下がさらに好ましく、５０質量％以下とすることもできる。 The content of the metal (a) in the negative electrode active material is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more from the viewpoint of obtaining a sufficient addition effect (such as charge / discharge capacity). From the viewpoint of sufficiently obtaining the effect of adding other components, etc., it is preferably 95% by mass or less, more preferably 90% by mass or less, further preferably 80% by mass or less, and can also be 50% by mass or less.
　負極活物質中の金属酸化物（ｂ）の含有率は、充放電サイクル特性等の点から、５質量％以上が好ましく、１５質量％以上がより好ましく、４０質量％以上にすることがさらに好ましく、５０質量％以上にすることもできる。他の成分の添加効果等を十分に得る点から、９０質量％以下が好ましく、８０質量％以下がより好ましく、７０質量％以下がさらに好ましい。 The content of the metal oxide (b) in the negative electrode active material is preferably 5% by mass or more, more preferably 15% by mass or more, and further preferably 40% by mass or more from the viewpoint of charge / discharge cycle characteristics and the like. , 50% by mass or more. 90 mass% or less is preferable from the point which fully obtains the addition effect of another component, etc., 80 mass% or less is more preferable, and 70 mass% or less is further more preferable.
　負極活物質が金属（ａ）と金属酸化物（ｂ）とを含む場合、負極活物質中の金属（ａ）と金属酸化物（ｂ）の質量比率（ａ／ｂ）は、特に制限はないが、５／９５～９０／１０の範囲に設定することができ、また１０／９０～８０／２０の範囲に設定することができ、さらに３０／７０～６０／４０の範囲に設定することができる。 When the negative electrode active material contains a metal (a) and a metal oxide (b), the mass ratio (a / b) of the metal (a) and the metal oxide (b) in the negative electrode active material is not particularly limited. Can be set in the range of 5/95 to 90/10, can be set in the range of 10/90 to 80/20, and can be set in the range of 30/70 to 60/40. it can.
　負極活物質中の炭素材料（ｃ）の含有率は、十分な添加効果を得る点から、１質量％以上が好ましく、２質量％以上がより好ましく、他の成分の添加効果等を十分に得る点から、５０質量％以下が好ましく、３０質量％質量％以下がより好ましい。 The content of the carbon material (c) in the negative electrode active material is preferably 1% by mass or more, more preferably 2% by mass or more from the viewpoint of obtaining a sufficient addition effect, and sufficient effects of addition of other components, etc. are obtained. From the viewpoint, 50% by mass or less is preferable, and 30% by mass or less is more preferable.
　負極活物質が金属（ａ）と金属酸化物（ｂ）と炭素材料（ｃ）とを含む場合、金属（ａ）、金属酸化物（ｂ）及び炭素材料（ｃ）の割合は、特に制限はないが、上記の含有率の範囲に従って設定することができる。金属（ａ）の含有割合は、金属（ａ）、金属酸化物（ｂ）及び炭素材料（ｃ）の合計に対し、例えば、５質量％以上が好ましく、１０質量％以上がより好ましく、２０質量％以上がさらに好ましく、また、９０質量％以下が好ましく、８０質量％以下がより好ましく、５０質量％以下に設定することもできる。金属酸化物（ｂ）の含有割合は、金属（ａ）、金属酸化物（ｂ）および炭素材料（ｃ）の合計に対し、例えば、５質量％以上が好ましく、１５質量％以上がより好ましく、４０質量％以上に設定することもでき、また、９０質量％以下が好ましく、８０質量％以下がより好ましく、７０質量％以下に設定することもできる。炭素材料（ｃ）の含有割合は、金属（ａ）、金属酸化物（ｂ）および炭素材料（ｃ）の合計に対し、例えば、１質量％以上が好ましく、２質量％以上がより好ましく、また、５０質量％以下が好ましく、３０質量％以下がより好ましい。 When the negative electrode active material includes a metal (a), a metal oxide (b), and a carbon material (c), the ratio of the metal (a), the metal oxide (b), and the carbon material (c) is not particularly limited. Although not, it can be set according to the above range of the content. The content ratio of the metal (a) is, for example, preferably 5% by mass or more, more preferably 10% by mass or more, and 20% by mass with respect to the total of the metal (a), the metal oxide (b), and the carbon material (c). % Or more is more preferable, 90 mass% or less is preferable, 80 mass% or less is more preferable, and it can also be set to 50 mass% or less. The content ratio of the metal oxide (b) is preferably, for example, 5% by mass or more, more preferably 15% by mass or more, with respect to the total of the metal (a), the metal oxide (b), and the carbon material (c). It can also be set to 40% by mass or more, preferably 90% by mass or less, more preferably 80% by mass or less, and can also be set to 70% by mass or less. The content ratio of the carbon material (c) is, for example, preferably 1% by mass or more, more preferably 2% by mass or more, with respect to the total of the metal (a), the metal oxide (b), and the carbon material (c). 50 mass% or less is preferable and 30 mass% or less is more preferable.
　金属（ａ）、金属酸化物（ｂ）および炭素材料（ｃ）の形状は、特に制限するものではないが、それぞれ粒子状のものを用いることができる。 The shape of the metal (a), the metal oxide (b), and the carbon material (c) is not particularly limited, but may be particulate.
　負極活物質の比表面積は、０．２ｍ２／ｇ以上が好ましく、１．０ｍ２／ｇ以上がより好ましく、２．０ｍ２／ｇ以上がさらに好ましく、一方、９．０ｍ２／ｇ以下が好ましく、８．０ｍ２／ｇ以下がより好ましく、７．０ｍ２／ｇ以下がさらに好ましい。ここで、比表面積は、通常のＢＥＴ比表面積測定法により得られる。 The specific surface area of the negative electrode active material is preferably 0.2 m 2 / g or more, more preferably 1.0 m 2 / g or more, still more preferably 2.0 m 2 / g or more, while 9.0 m 2 / g or less. Preferably, 8.0 m 2 / g or less is more preferable, and 7.0 m 2 / g or less is more preferable. Here, the specific surface area is obtained by an ordinary BET specific surface area measurement method.
　負極活物質の平均粒径は、０．０１μｍ以上が好ましく、０．１μｍ以上がより好ましく、０．２μｍ以上がさらに好ましく、一方、３０μｍ以下が好ましく、２０μｍ以下がより好ましい。ここで、平均粒径は、５０％累積径Ｄ５０（メジアン径）であり、レーザー回折散乱法による粒度分布測定により得られる。 The average particle diameter of the negative electrode active material is preferably 0.01 μm or more, more preferably 0.1 μm or more, further preferably 0.2 μm or more, and on the other hand, 30 μm or less is more preferable, and 20 μm or less is more preferable. Here, the average particle diameter is 50% cumulative diameter D 50 (median diameter), and is obtained by particle size distribution measurement by a laser diffraction scattering method.
　負極用結着剤としては、ポリフッ化ビニリデン、ビニリデンフルオライド－ヘキサフルオロプロピレン共重合体、ビニリデンフルオライド－テトラフルオロエチレン共重合体、スチレン－ブタジエン共重合ゴム、ポリテトラフルオロエチレン、ポリプロピレン、ポリエチレン、ポリイミド、ポリアミドイミド等を用いることができる。中でも、結着性が強いことから、ポリイミドまたはポリアミドイミドが好ましい。負極における負極用結着剤の含有量は、トレードオフの関係にある結着力とエネルギー密度の観点から、負極活物質１００質量部に対して、５～２５質量部が好ましく、７～２０質量部がより好ましい。 Examples of the binder for the negative electrode include polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, styrene-butadiene copolymer rubber, polytetrafluoroethylene, polypropylene, polyethylene, Polyimide, polyamideimide, or the like can be used. Of these, polyimide or polyamideimide is preferred because of its high binding properties. The content of the binder for the negative electrode in the negative electrode is preferably 5 to 25 parts by mass, and 7 to 20 parts by mass with respect to 100 parts by mass of the negative electrode active material, from the viewpoints of binding force and energy density that are in a trade-off relationship. Is more preferable.
　負極集電体としては、電気化学的な安定性から、銅、ニッケル、銀が好ましい。その形状としては、箔、平板状、メッシュ状が挙げられる。 As the negative electrode current collector, copper, nickel, and silver are preferable in view of electrochemical stability. Examples of the shape include foil, flat plate, and mesh.
　負極は、例えば、負極集電体上に、負極活物質と負極用結着剤を含む負極活物質層を形成することにより作製できる。負極活物質層は、一般的なスラリー塗布法で形成することができる。具体的には、負極活物質、結着剤及び溶媒を含むスラリーを調製し、これを負極集電体上に塗布し、乾燥し、必要に応じて圧縮し、成形することで、負極を作製することができる。負極スラリーは、負極活物質を、負極結着剤とともに、Ｎ－メチル－２－ピロリドン（ＮＭＰ）等の溶剤中に分散混練することで得ることができる。負極スラリーの塗布方法としては、ドクターブレード法、ダイコーター法、ディップコーティング法が挙げられる。あらかじめ負極活物質層を形成した後に、蒸着、スパッタ等の方法で金属薄膜を形成して、この金属薄膜を負極集電体としてもよい。 The negative electrode can be produced, for example, by forming a negative electrode active material layer containing a negative electrode active material and a negative electrode binder on a negative electrode current collector. The negative electrode active material layer can be formed by a general slurry coating method. Specifically, a negative electrode is prepared by preparing a slurry containing a negative electrode active material, a binder, and a solvent, applying the slurry onto a negative electrode current collector, drying, compressing and molding as necessary. can do. The negative electrode slurry can be obtained by dispersing and kneading the negative electrode active material in a solvent such as N-methyl-2-pyrrolidone (NMP) together with the negative electrode binder. Examples of the method for applying the negative electrode slurry include a doctor blade method, a die coater method, and a dip coating method. After forming a negative electrode active material layer in advance, a metal thin film may be formed by a method such as vapor deposition or sputtering, and this metal thin film may be used as a negative electrode current collector.
　［２］正極
　正極は、例えば、正極活物質と正極用結着剤を含む正極活物質層が正極集電体上に設けられたものを用いることができる。 [2] Positive electrode As the positive electrode, for example, a positive electrode having a positive electrode active material layer containing a positive electrode active material and a positive electrode binder on a positive electrode current collector can be used.
　正極活物質としては、ＬｉＭｎＯ２、ＬｉｘＭｎ２Ｏ４（０＜ｘ＜２）等の層状構造またはスピネル構造を有するマンガン酸リチウム；マンガン酸リチウムのＭｎの一部を他の金属で置き換えたリチウム金属酸化物；ＬｉＣｏＯ２、ＬｉＮｉＯ２、これらの遷移金属（Ｃｏ、Ｎｉ）の一部を他の金属で置き換えたリチウム金属酸化物；ＬｉＮｉ１／３Ｃｏ１／３Ｍｎ１／３Ｏ２などの特定の遷移金属が遷移金属全体の半数（原子数比）を超えないリチウム遷移金属酸化物；これらのリチウム遷移金属酸化物において化学量論組成よりもＬｉを過剰に含むリチウム金属酸化物等が挙げられる。具体的には、ＬｉαＮｉβＣｏγＡｌδＯ２（０．８≦α≦１．２、β＋γ＋δ＝１、０．５＜β、０＜γ、０＜δ）、又はＬｉαＮｉβＣｏγＭｎδＯ２（０．８≦α≦１．２、β＋γ＋δ＝１、０．５＜β、０＜γ、０＜δ）が挙げられる。これらのリチウム金属酸化物において、γ≧０．１、δ≧０．０１に設定できる。特に、ＬｉαＮｉβＣｏγＡｌδＯ２（１≦α≦１．２、β＋γ＋δ＝１、β≧０．７、γ≦０．２）、又はＬｉαＮｉβＣｏγＭｎδＯ２（１≦α≦１．２、β＋γ＋δ＝１、β≧０．６、γ≦０．２）が好ましい。また、ＬｉαＮｉβＣｏγＭｎδＡｌεＭｇζＯ２（１≦α≦１．２、β＋γ＋δ＋ε＋ζ＝１、β≧０．５、０≦γ≦０．２、０．０１≦δ≦０．４９、０≦ε≦０．３）が好ましい。正極活物質は、一種を単独で、または二種以上を組み合わせて使用することができる。 As a positive electrode active material, lithium manganate having a layered structure such as LiMnO 2 or LixMn 2 O 4 (0 <x <2) or a spinel structure; lithium metal in which a part of Mn of lithium manganate is replaced with another metal Oxides; LiCoO 2 , LiNiO 2 , lithium metal oxides in which some of these transition metals (Co, Ni) are replaced with other metals; specificities such as LiNi 1/3 Co 1/3 Mn 1/3 O 2 Transition metal oxides that do not exceed half the total number of transition metals (atomic ratio); lithium metal oxides that contain Li in excess of the stoichiometric composition in these lithium transition metal oxides, etc. . Specifically, Li α Ni β Co γ Al δ O 2 (0.8 ≦ α ≦ 1.2, β + γ + δ = 1, 0.5 <β, 0 <γ, 0 <δ), or Li α Ni β Co γ Mn δ O 2 (0.8 ≦ α ≦ 1.2, β + γ + δ = 1, 0.5 <β, 0 <γ, 0 <δ). In these lithium metal oxides, γ ≧ 0.1 and δ ≧ 0.01 can be set. In particular, Li α Ni β Co γ Al δ O 2 (1 ≦ α ≦ 1.2, β + γ + δ = 1, β ≧ 0.7, γ ≦ 0.2), or Li α Ni β Co γ Mn δ O 2 ( 1 ≦ α ≦ 1.2, β + γ + δ = 1, β ≧ 0.6, γ ≦ 0.2) are preferable. Li α Ni β Co γ Mn δ Al ε Mg ζ O 2 (1 ≦ α ≦ 1.2, β + γ + δ + ε + ζ = 1, β ≧ 0.5, 0 ≦ γ ≦ 0.2, 0.01 ≦ δ ≦ 0 .49, 0 ≦ ε ≦ 0.3). A positive electrode active material can be used individually by 1 type or in combination of 2 or more types.
　正極用結着剤としては、通常の負極用結着剤と同様のものを用いることができる。中でも、汎用性や低コストの観点から、ポリフッ化ビニリデンが好ましい。使用する正極用結着剤の量は、トレードオフの関係にある結着力とエネルギー密度の観点から、正極活物質１００質量部に対して、２～１０質量部が好ましい。 As the positive electrode binder, the same negative electrode binder as that used for normal negative electrodes can be used. Among these, polyvinylidene fluoride is preferable from the viewpoint of versatility and low cost. The amount of the positive electrode binder used is preferably 2 to 10 parts by mass with respect to 100 parts by mass of the positive electrode active material, from the viewpoints of binding force and energy density which are in a trade-off relationship.
　正極集電体としては、電気化学的な安定性の観点から、例えば、アルミニウム、ニッケル、銀、ＳＵＳ、バルブメタル、又はそれらの合金を使用することができる。その形状としては、箔、平板状、メッシュ状のものが挙げられる。特に、アルミニウム箔を好適に用いることができる。 As the positive electrode current collector, for example, aluminum, nickel, silver, SUS, valve metal, or an alloy thereof can be used from the viewpoint of electrochemical stability. Examples of the shape include foil, flat plate, and mesh. In particular, an aluminum foil can be preferably used.
　正極活物質を含む正極活物質層には、インピーダンスを低下させる目的で、導電補助材を添加してもよい。導電補助材としては、グラファイト、カーボンブラック、アセチレンブラック等の炭素質微粒子が挙げられる。 A conductive auxiliary material may be added to the positive electrode active material layer containing the positive electrode active material for the purpose of reducing impedance. Examples of the conductive auxiliary material include carbonaceous fine particles such as graphite, carbon black, and acetylene black.
　正極は、例えば、正極活物質、結着剤及び溶媒（さらに必要により導電補助材）を含むスラリーを調製し、これを負極集電体上に塗布し、乾燥することにより、正極集電体上に正極活物質層を形成することにより作製できる。 The positive electrode is prepared by, for example, preparing a slurry containing a positive electrode active material, a binder, and a solvent (and, if necessary, a conductive auxiliary material), applying the slurry onto the negative electrode current collector, and drying the slurry. Can be produced by forming a positive electrode active material layer.
　［３］セパレータ
　セパレータとしては、ポリプロピレン、ポリエチレン等のポリオレフィンや、フッ素樹脂等からなる多孔質フィルムや不織布を用いることができる。また、セパレータとして、それらを積層したものを用いることもできる。 [3] Separator As the separator, a polyolefin such as polypropylene or polyethylene, a porous film or a nonwoven fabric made of a fluororesin, or the like can be used. Moreover, what laminated | stacked them can also be used as a separator.
　［４］電極対の構造
　電極対の構造としては、円筒型捲回構造、偏平型捲回構造、つづら折構造、積層ラミネート型構造などが挙げられるが、特に、積層ラミネート型構造が好ましい。積層ラミネート型構造では、電極及びセパレータが平面形状のまま積層されており、Ｒの小さい部分（捲回構造の巻き芯に近い領域または折り返す部位にあたる領域）が存在しない。そのため、充放電に伴う体積変化が大きい活物質を用いた場合、捲回構造を持つ電池に比べて、充放電に伴う電極の体積変化による悪影響を受けにくい。 [4] Structure of electrode pair Examples of the structure of the electrode pair include a cylindrical wound structure, a flat wound structure, a zigzag folded structure, and a laminated laminate structure, and a laminated laminate structure is particularly preferable. In the laminated laminate type structure, the electrodes and the separator are laminated in a planar shape, and there is no portion with a small R (a region close to the winding core of the wound structure or a region corresponding to the folded portion). Therefore, when an active material having a large volume change associated with charging / discharging is used, it is less likely to be adversely affected by the volume change of the electrode associated with charging / discharging than a battery having a wound structure.
　［５］外装体
　外装体としては、非水電解液に安定で、かつ十分な水蒸気バリア性を持つラミネートフィルムを用いることができる。例えば、このような外装体としては、アルミニウム、シリカをコーティングしたポリプロピレン、ポリエチレン等のラミネートフィルムを用いることができる。特に、汎用性やコスト等の観点から、アルミニウムラミネートフィルムを用いることが好ましい。 [5] Exterior Body As the exterior body, a laminate film that is stable in a non-aqueous electrolyte and has a sufficient water vapor barrier property can be used. For example, as such an outer package, a laminate film such as polypropylene or polyethylene coated with aluminum or silica can be used. In particular, it is preferable to use an aluminum laminate film from the viewpoints of versatility and cost.
　外装体としてラミネートフィルムを用いた非水電解液二次電池の場合、外装体として金属缶を用いた非水電解液二次電池に比べて、ガスが発生に起因する電池の体積変化や電極の歪みが生じやすい。これは、ラミネートフィルムが金属缶に比べて非水電解液二次電池の内圧により変形しやすいためである。さらに、外装体としてラミネートフィルムを用いた非水電解液二次電池を封止する際には、通常、電池内圧を大気圧より低くし、内部に余分な空間がないため、電池内でガスが発生した場合に直ちに電池の体積変化や電極の変形につながりやすい。本実施形態による非水電解液二次電池は、このような問題の発生を抑えることができる。それにより、長期信頼性に優れた、積層ラミネート型の非水電解液二次電池を提供することができる。 In the case of a non-aqueous electrolyte secondary battery using a laminate film as an exterior body, compared to a non-aqueous electrolyte secondary battery using a metal can as an exterior body, the volume change of the battery or the electrode Distortion is likely to occur. This is because the laminate film is more easily deformed by the internal pressure of the nonaqueous electrolyte secondary battery than the metal can. Furthermore, when sealing a non-aqueous electrolyte secondary battery using a laminate film as an outer package, the internal pressure of the battery is usually lower than atmospheric pressure and there is no extra space inside. When this occurs, it tends to immediately lead to battery volume changes and electrode deformation. The nonaqueous electrolyte secondary battery according to the present embodiment can suppress the occurrence of such a problem. Thereby, a laminated laminate type non-aqueous electrolyte secondary battery having excellent long-term reliability can be provided.
　以上に説明した二次電池（単電池）が複数個電気的に接続されチューブやケース等によりパックされた組電池を提供することができる。組電池内の単電池の接続は、直列、並列、その両方で行うことできる。単電池の個数や接続方法により容量や電圧を調節することができる。この組電池をさらに複数、直列または並列に接続することができる。 It is possible to provide an assembled battery in which a plurality of the secondary batteries (single cells) described above are electrically connected and packed with a tube or a case. The cells in the assembled battery can be connected in series, in parallel, or both. The capacity and voltage can be adjusted according to the number of cells and the connection method. A plurality of the assembled batteries can be connected in series or in parallel.
　上記の二次電池や組電池は、車両の駆動用電源として用いることができ、高寿命で信頼性の高い車両を提供することができる。車両としては、ハイブリッド自動車、電気自動車電動バイク、電動アシスト自転車等に適用できる。４輪車や２輪車に限定されず、３輪車も含まれ、車輪の数は限定されない。さらに電車などの移動／輸送媒体の各種電源にも適用できる。 The above-mentioned secondary battery or assembled battery can be used as a power source for driving a vehicle, and can provide a vehicle with a long life and high reliability. The vehicle can be applied to a hybrid vehicle, an electric vehicle, an electric motorcycle, an electric assist bicycle, and the like. It is not limited to a four-wheel vehicle or a two-wheel vehicle, and a three-wheel vehicle is also included, and the number of wheels is not limited. Furthermore, it can be applied to various power sources for moving / transporting media such as trains.
　以下、本発明の実施形態について実施例を挙げてさらに具体的に説明する。 Hereinafter, the embodiment of the present invention will be described more specifically with reference to examples.
　（実施例１）
　酸化ケイ素粉末（酸化ケイ素とケイ素との混合物）を、メタンガスを含む雰囲気下１１５０℃で６時間ＣＶＤ処理を行うことで、酸化ケイ素中のケイ素がナノクラスター化し、かつ表面がカーボンで被覆されたケイ素－酸化ケイ素－カーボン複合体（負極活物質）を得た。ケイ素／酸化ケイ素／カーボンの質量比＝２９／６１／１０となるように調整した。 (Example 1)
Silicon oxide powder (mixture of silicon oxide and silicon) is subjected to CVD treatment at 1150 ° C. for 6 hours in an atmosphere containing methane gas, so that silicon in silicon oxide is nanoclustered and silicon is coated with carbon. A silicon oxide-carbon composite (negative electrode active material) was obtained. The mass ratio of silicon / silicon oxide / carbon was adjusted to be 29/61/10.
　上記負極活物質（平均粒径Ｄ５０＝５μｍ）と、負極用結着剤としてのポリイミドとの質量比が８５：１５となるように、負極活物質とポリアミック酸（宇部興産株式会社製、商品名：ＵワニスＡ）とを計量し、それらをｎ－メチルピロリドンと混合して、負極スラリーを調製した。この負極スラリーを厚さ１０μｍの銅箔の表面に１ｃｍ２当たり２．５ｍｇの量となるように塗布し、乾燥した。同様に、銅箔の裏面にも負極スラリーを塗布し、乾燥した。その後、窒素雰囲気３５０℃の熱処理を行い、２６ｍｍ×６５ｍｍに切断し、負極を得た。 The negative electrode active material and the polyamic acid (manufactured by Ube Industries, Ltd., product) so that the mass ratio of the negative electrode active material (average particle size D 50 = 5 μm) to the polyimide as the negative electrode binder is 85:15. Name: U Varnish A) was weighed and mixed with n-methylpyrrolidone to prepare a negative electrode slurry. This negative electrode slurry was applied on the surface of a copper foil having a thickness of 10 μm so as to be 2.5 mg per 1 cm 2 and dried. Similarly, the negative electrode slurry was applied to the back surface of the copper foil and dried. Thereafter, heat treatment was performed at 350 ° C. in a nitrogen atmosphere, and cut into 26 mm × 65 mm to obtain a negative electrode.
　正極活物質としてのニッケル酸リチウム（ＬｉＮｉ０．８０Ｃｏ０．１５Ａｌ０．１５Ｏ２）と、導電補助材としてのカーボンブラックと、正極用結着剤としてのポリフッ化ビニリデンとを、９０：５：５（活物質：導電補助剤：結着剤）の質量比で計量し、それらをｎ－メチルピロリドンと混合して、正極スラリーを調製した。この正極スラリーを厚さ２０μｍのアルミニウム箔の表面に１ｃｍ２当たり２０ｍｇの量となるように塗布、乾燥し、プレスを行った。同様に、アルミニウム箔の裏面にも正極スラリーを塗布、乾燥し、プレスを行った。その後、２３ｍｍ×６４ｍｍに切断し、正極を得た。 Lithium nickelate (LiNi 0.80 Co 0.15 Al 0.15 O 2 ) as a positive electrode active material, carbon black as a conductive auxiliary material, and polyvinylidene fluoride as a binder for the positive electrode, 90: A positive electrode slurry was prepared by weighing at a mass ratio of 5: 5 (active material: conductive auxiliary agent: binder) and mixing them with n-methylpyrrolidone. This positive electrode slurry was applied to the surface of an aluminum foil having a thickness of 20 μm so as to have an amount of 20 mg per cm 2 , dried and pressed. Similarly, the positive electrode slurry was applied to the back surface of the aluminum foil, dried, and pressed. Then, it cut | disconnected to 23 mm x 64 mm, and the positive electrode was obtained.
　得られた正極の１層と負極の２層を、セパレータとしてのポリプロピレン多孔質フィルム（Ｃｅｌｇａｒｄ　ＬＬＣ製、商品名：セルガード＃２５００）を介して交互に重ねた。 1 layer of the obtained positive electrode and 2 layers of the negative electrode were alternately stacked via a polypropylene porous film (manufactured by Celgard LLC, trade name: Celgard # 2500) as a separator.
　正極活物質に覆われていない正極集電体端部にアルミニウム製の正極端子を溶接し、負極活物質に覆われていない負極集電体の端部同士を溶接し、その溶接箇所にニッケル製の負極端子を溶接して、平面状の電極積層体を得た。 We weld the positive electrode terminals made of aluminum to the ends of the positive electrode current collector not covered with the positive electrode active material, weld the ends of the negative electrode current collector not covered with the negative electrode active material, and make the welds made of nickel The negative electrode terminal was welded to obtain a planar electrode laminate.
　ＥＣ／ＤＥＣを３／７（体積比）で混合した非水系溶媒に、ＬｉＰＦ６を１モル／Ｌの濃度になるように溶解させ、さらにビニル化合物としてエチレングリコールジメタクリレートを２ｗｔ％の濃度になるように溶解させ、非水電解液を得た。 LiPF 6 is dissolved in a non-aqueous solvent mixed with EC / DEC at 3/7 (volume ratio) to a concentration of 1 mol / L, and ethylene glycol dimethacrylate as a vinyl compound has a concentration of 2 wt%. Thus, a nonaqueous electrolytic solution was obtained.
　上記電極積層体を、外装体としてのアルミニウムラミネートフィルムでタブ（端子）が出るように包み、非水電解液を注入した後、減圧しつつ封止して、非水電解液二次電池を得た。 The electrode laminate is wrapped with an aluminum laminate film as an outer package so that tabs (terminals) come out, and after injecting a nonaqueous electrolyte, it is sealed under reduced pressure to obtain a nonaqueous electrolyte secondary battery. It was.
　（実施例２）
　エチレングリコールジメタクリレートに代えて、ジエチレングリコールジメタクリレートを２ｗｔ％溶解したこと以外は、実施例１と同様にして非水電解液二次電池を作製した。 (Example 2)
A nonaqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that 2 wt% of diethylene glycol dimethacrylate was dissolved instead of ethylene glycol dimethacrylate.
　（比較例１）
　ビニル化合物を非水系溶媒に溶解しなかったこと以外は、実施例１と同様にして非水電解液二次電池を作製した。 (Comparative Example 1)
A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that the vinyl compound was not dissolved in the non-aqueous solvent.
　（比較例２）
　エチレングリコールジメタクリレートに代えて、メタクリル酸メチルを２ｗｔ％溶解したこと以外は、実施例１と同様にして非水電解液二次電池を作製した。 (Comparative Example 2)
A nonaqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that 2 wt% of methyl methacrylate was dissolved in place of ethylene glycol dimethacrylate.
　（比較例３）
　エチレングリコールジメタクリレートに代えて、ブチルビニルエーテルを１ｗｔ％溶解したこと以外は、実施例１と同様にして非水電解液二次電池を作製した。 (Comparative Example 3)
A nonaqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that 1 wt% of butyl vinyl ether was dissolved instead of ethylene glycol dimethacrylate.
　（比較例４）
　エチレングリコールジメタクリレートに代えて、ビニレンカーボネートを２ｗｔ％溶解したこと以外は、実施例１と同様にして非水電解液二次電池を作製した。 (Comparative Example 4)
A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that 2 wt% of vinylene carbonate was dissolved in place of ethylene glycol dimethacrylate.
　（６０℃保存試験）
　作製した非水電解液二次電池を、４．２Ｖまで充電した後、６０℃に保った恒温槽中に入れて一週間放置し、アルキメデス法によって体積を測定し、下記式に従って体積増加率を算出し、評価を行った。試験結果を表１に示す。 (60 ° C storage test)
The prepared non-aqueous electrolyte secondary battery is charged to 4.2 V, then placed in a thermostat kept at 60 ° C. and left for one week, and the volume is measured by the Archimedes method. Calculation and evaluation were performed. The test results are shown in Table 1.
　体積増加率（％）＝１００×（１週間放置時の体積－初期の体積）／初期の体積
　評価の判定は下記の基準に従って行った。 Volume increase rate (%) = 100 × (volume after standing for one week−initial volume) / initial volume Evaluation was evaluated according to the following criteria.
　　Ａ：体積増加率が３０％以下、
　　Ｂ：体積増加率が３０％を超える。 A: Volume increase rate is 30% or less,
B: Volume increase rate exceeds 30%.
　（６０℃サイクル試験）
　６０℃に保った恒温槽中で、４．２Ｖまでの充電と２．５Ｖまでの放電を１Ｃレートで繰り返すサイクル試験を行い、下記式に従って容量維持率を算出し、評価を行った。試験結果を表１に示す。 (60 ° C cycle test)
A cycle test in which charging up to 4.2 V and discharging up to 2.5 V were repeated at a 1 C rate in a constant temperature bath maintained at 60 ° C., and a capacity maintenance rate was calculated according to the following formula and evaluated. The test results are shown in Table 1.
　容量維持率（％）＝１００×（１００サイクル目の放電容量）／（１サイクル目の放電容量）
　評価の判定は下記の基準に従って行った。 Capacity retention rate (%) = 100 × (discharge capacity at the 100th cycle) / (discharge capacity at the first cycle)
Evaluation was determined according to the following criteria.
　　Ａ：容量維持率が８５％を超える、
　　Ｂ：容量維持率が８０％を超え８５％以下、
　　Ｃ：容量維持率が７０％を超え８０％以下、
　　Ｄ：容量維持率が７０％以下。 A: Capacity maintenance rate exceeds 85%,
B: Capacity maintenance rate is over 80% and 85% or less,
C: Capacity maintenance rate is over 70% and 80% or less,
D: Capacity maintenance rate is 70% or less.
Figure JPOXMLDOC01-appb-T000003
 　表１に示すように、実施例１及び２の非水電解液二次電池は、６０℃での保存試験およびサイクル試験において優れた結果（低い体積増加率と高い容量維持率）を示した。これは、非水電解液に含まれる多官能ビニル化合物の電解重合により、負極表面にポリマー皮膜が形成しためと考えられる。
Figure JPOXMLDOC01-appb-T000003
 As shown in Table 1, the nonaqueous electrolyte secondary batteries of Examples 1 and 2 showed excellent results (low volume increase rate and high capacity retention rate) in the storage test and cycle test at 60 ° C. This is presumably because a polymer film is formed on the negative electrode surface by electrolytic polymerization of the polyfunctional vinyl compound contained in the non-aqueous electrolyte.
　一方、比較例２及び３は、ビニル化合物を添加していない比較例１と比較して体積増加率が低いが、実施例１及び２と比較すると著しく大きく、電解液の分解を十分に抑制できていないことがわかる。また、比較例２及び３で用いたビニル化合物は、サイクル特性（容量維持率）の向上効果も示していないことがわかる。比較例４のブチルビニルエーテルは、カチオン重合性のため支持塩と反応してゲル化したため容量が上がらず、６０℃保存試験での体積増加は見られず、６０℃サイクル試験の容量維持率も低い結果となった。 On the other hand, Comparative Examples 2 and 3 have a lower volume increase rate than Comparative Example 1 in which no vinyl compound is added, but are significantly larger than Examples 1 and 2, and can sufficiently suppress the decomposition of the electrolyte. You can see that it is not. Moreover, it turns out that the vinyl compound used in Comparative Examples 2 and 3 does not show the effect of improving cycle characteristics (capacity maintenance ratio). Since the butyl vinyl ether of Comparative Example 4 reacted with the supporting salt due to cationic polymerization and gelled, the capacity did not increase, the volume increase in the 60 ° C. storage test was not observed, and the capacity retention rate of the 60 ° C. cycle test was also low. As a result.
　以上の結果から、本実施形態によれば、エネルギー密度が高く、且つ長期安定性に優れた非水電解液二次電池を提供できることがわかる。 From the above results, it can be seen that according to the present embodiment, a non-aqueous electrolyte secondary battery having high energy density and excellent long-term stability can be provided.
　以上、実施形態および実施例を参照して本発明を説明したが、本発明は上記実施形態および実施例に限定されるものではない。本発明の構成や詳細には、本発明の範囲内で当業者が理解し得る様々な変更をすることができる。 As mentioned above, although this invention was demonstrated with reference to embodiment and an Example, this invention is not limited to the said embodiment and Example. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.
　この出願は、２０１１年８月１７日に出願された日本出願特願２０１１－１７８４４７を基礎とする優先権を主張し、その開示の全てをここに取り込む。 This application claims priority based on Japanese Patent Application No. 2011-178447 filed on August 17, 2011, the entire disclosure of which is incorporated herein.
　本実施形態は、電源を必要とするあらゆる産業分野、ならびに電気的エネルギーの輸送、貯蔵および供給に関する産業分野にて利用することができる。具体的には、携帯電話、ノートパソコンなどのモバイル機器の電源；電気自動車、ハイブリッドカー、電動バイク、電動アシスト自転車、電車などの電動車両の電源；衛星や潜水艦などの移動・輸送用媒体の電源；ＵＰＳ（無停電電源装置）などのバックアップ電源；太陽光発電、風力発電などで発電した電力を貯める蓄電設備などに利用することができる。 This embodiment can be used in all industrial fields that require a power source and in industrial fields related to the transport, storage, and supply of electrical energy. Specifically, power sources for mobile devices such as mobile phones and laptop computers; power sources for electric vehicles such as electric cars, hybrid cars, electric motorcycles, electric assist bicycles, and trains; power sources for mobile and transport media such as satellites and submarines A backup power source such as a UPS (uninterruptible power supply); a power storage facility for storing power generated by solar power generation, wind power generation, or the like.
　１　負極
　２　セパレータ
　３　正極
　４　負極集電体
　５　正極集電体
　６　正極端子
　７　負極端子 DESCRIPTION OF SYMBOLS 1 Negative electrode 2 Separator 3 Positive electrode 4 Negative electrode collector 5 Positive electrode collector 6 Positive electrode terminal 7 Negative electrode terminal

Claims (16)

  1. 　正極と、セパレータと、該セパレータを介して該正極と対向配置された負極と、非水電解液と、これらを内包する外装体とを含む、非水電解液二次電池であって、
    　前記負極は、リチウムと合金可能な金属（ａ）を含む負極活物質と、結着剤とを含み、
    　前記非水電解液は、複数の末端二重結合を有するビニル化合物を含有する、非水電解液二次電池。     A non-aqueous electrolyte secondary battery comprising a positive electrode, a separator, a negative electrode disposed opposite to the positive electrode via the separator, a non-aqueous electrolyte, and an outer package containing them,
    The negative electrode includes a negative electrode active material containing a metal (a) that can be alloyed with lithium, and a binder.
    The non-aqueous electrolyte secondary battery includes a vinyl compound having a plurality of terminal double bonds.
  2. 　前記ビニル化合物は、ラジカル重合またはアニオン重合性能を有する、請求項１に記載の非水電解液二次電池。 The non-aqueous electrolyte secondary battery according to claim 1, wherein the vinyl compound has radical polymerization or anion polymerization performance.
  3. 　前記非水電解液における前記ビニル化合物の含有率は、０．０１～１０質量％である、請求項１又は２に記載の非水電解液二次電池。 The non-aqueous electrolyte secondary battery according to claim 1 or 2, wherein the content of the vinyl compound in the non-aqueous electrolyte is 0.01 to 10% by mass.
  4. 　前記ビニル化合物が、前記末端二重結合を含む基として、メタクリロイル基、アクリロイル基、ビニルフェニル基、１，３－ブタジエニル基、シアノアクリロイル基からなる群から選ばれる基を有する、請求項１から３のいずれか一項に記載の非水電解液二次電池。 The vinyl compound has a group selected from the group consisting of a methacryloyl group, an acryloyl group, a vinylphenyl group, a 1,3-butadienyl group, and a cyanoacryloyl group as the group containing the terminal double bond. The nonaqueous electrolyte secondary battery according to any one of the above.
  5. 　前記ビニル化合物が、多官能（メタ）アクリレートである、請求項１から３のいずれか一項に記載の非水電解液二次電池。 The non-aqueous electrolyte secondary battery according to any one of claims 1 to 3, wherein the vinyl compound is a polyfunctional (meth) acrylate.
  6. 　前記負極の表面に、前記ビニル化合物の電解重合反応物が形成されている、請求項１から５のいずれか一項に記載の非水電解液二次電池。 The nonaqueous electrolyte secondary battery according to any one of claims 1 to 5, wherein an electrolytic polymerization reaction product of the vinyl compound is formed on a surface of the negative electrode.
  7. 　前記負極は、前記金属（ａ）としてシリコンを含む、請求項１から６のいずれか一項に記載の非水電解液二次電池。 The non-aqueous electrolyte secondary battery according to any one of claims 1 to 6, wherein the negative electrode contains silicon as the metal (a).
  8. 　前記負極は、さらに金属酸化物（ｂ）を含む、請求項１から７のいずれか一項に記載の非水電解液二次電池。 The non-aqueous electrolyte secondary battery according to any one of claims 1 to 7, wherein the negative electrode further contains a metal oxide (b).
  9. 　前記負極は、前記金属酸化物（ｂ）として、前記金属（ａ）を構成する金属の酸化物を含む、請求項８に記載の非水電解液二次電池。 The non-aqueous electrolyte secondary battery according to claim 8, wherein the negative electrode includes a metal oxide constituting the metal (a) as the metal oxide (b).
  10. 　前記負極は、前記金属酸化物（ｂ）として酸化シリコンを含む、請求項８に記載の非水電解液二次電池。 The non-aqueous electrolyte secondary battery according to claim 8, wherein the negative electrode contains silicon oxide as the metal oxide (b).
  11. 　前記金属酸化物（ｂ）の全部または一部がアモルファス構造を有する、請求項８から１０のいずれか一項に記載の非水電解液二次電池。 The non-aqueous electrolyte secondary battery according to any one of claims 8 to 10, wherein all or part of the metal oxide (b) has an amorphous structure.
  12. 　前記金属（ａ）の全部または一部が、前記金属酸化物（ｂ）中に分散している、請求項８から１１のいずれか一項に記載の非水電解液二次電池。 The non-aqueous electrolyte secondary battery according to any one of claims 8 to 11, wherein all or part of the metal (a) is dispersed in the metal oxide (b).
  13. 　前記正極と前記負極との電極対が複数積層配置された積層型構造を有する、請求項１から１２のいずれか一項に記載の非水電解液二次電池。 The nonaqueous electrolyte secondary battery according to any one of claims 1 to 12, which has a stacked structure in which a plurality of electrode pairs of the positive electrode and the negative electrode are arranged in a stacked manner.
  14. 　前記外装体は、ラミネートフィルムからなる、請求項１から１３のいずれか一項に記載の非水電解液二次電池。 The non-aqueous electrolyte secondary battery according to any one of claims 1 to 13, wherein the exterior body is made of a laminate film.
  15. 　前記非水電解液二次電池は、電気自動車用の二次電池である、請求項１から１４のいずれか一項に記載の非水電解液二次電池。 The nonaqueous electrolyte secondary battery according to any one of claims 1 to 14, wherein the nonaqueous electrolyte secondary battery is a secondary battery for an electric vehicle.
  16. 　正極と、セパレータと、該セパレータを介して該正極と対向配置された負極を含む電極積層体を形成する工程と、
    　前記電極積層体を外装体で包む工程と、
    　非水電解液を注入する工程とを有し、
    　前記負極の形成において、リチウムと合金可能な金属（ａ）を含む負極活物質を使用し、
    　前記非水電解液として、複数の末端二重結合を有するビニル化合物を含有する電解液を使用する、非水電解液二次電池の製造方法。     Forming an electrode laminate including a positive electrode, a separator, and a negative electrode disposed opposite to the positive electrode via the separator;
    Wrapping the electrode laminate with an outer package;
    A step of injecting a non-aqueous electrolyte,
    In forming the negative electrode, using a negative electrode active material containing a metal (a) that can be alloyed with lithium,
    A method for producing a non-aqueous electrolyte secondary battery, wherein an electrolyte solution containing a vinyl compound having a plurality of terminal double bonds is used as the non-aqueous electrolyte solution.
PCT/JP2012/067568 2011-08-17 2012-07-10 Non-aqueous electrolyte secondary cell WO2013024648A1 (en)

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WO2013122145A1 (en) * 2012-02-17 2013-08-22 日本電気株式会社 Lithium secondary battery and electrolyte for lithium secondary battery
CN112467221A (en) * 2020-12-02 2021-03-09 珠海市赛纬电子材料股份有限公司 Additive for inhibiting silicon negative electrode expansion and electrolyte containing additive
EP4044314A4 (en) * 2020-03-27 2023-05-31 Lg Energy Solution, Ltd. Electrolyte for lithium-sulfur battery, and lithium-sulfur battery including same

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JP2010205474A (en) * 2009-03-02 2010-09-16 Sanwa Yuka Kogyo Kk Nonaqueous electrolyte and lithium ion secondary battery including the same

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JP2010205474A (en) * 2009-03-02 2010-09-16 Sanwa Yuka Kogyo Kk Nonaqueous electrolyte and lithium ion secondary battery including the same

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WO2013122145A1 (en) * 2012-02-17 2013-08-22 日本電気株式会社 Lithium secondary battery and electrolyte for lithium secondary battery
EP4044314A4 (en) * 2020-03-27 2023-05-31 Lg Energy Solution, Ltd. Electrolyte for lithium-sulfur battery, and lithium-sulfur battery including same
CN112467221A (en) * 2020-12-02 2021-03-09 珠海市赛纬电子材料股份有限公司 Additive for inhibiting silicon negative electrode expansion and electrolyte containing additive

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