WO2014054355A1 - Sealed cell and method for manufacturing same - Google Patents

Sealed cell and method for manufacturing same Download PDF

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Publication number
WO2014054355A1
WO2014054355A1 PCT/JP2013/072765 JP2013072765W WO2014054355A1 WO 2014054355 A1 WO2014054355 A1 WO 2014054355A1 JP 2013072765 W JP2013072765 W JP 2013072765W WO 2014054355 A1 WO2014054355 A1 WO 2014054355A1
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WIPO (PCT)
Prior art keywords
negative electrode
battery case
sealed battery
battery
positive electrode
Prior art date
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PCT/JP2013/072765
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French (fr)
Japanese (ja)
Inventor
阿部　浩史
春樹 上剃
前園　寛志
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日立マクセル株式会社
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Priority to JP2014539640A priority Critical patent/JP5913611B2/en
Publication of WO2014054355A1 publication Critical patent/WO2014054355A1/en

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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
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings, jackets or wrappings of a single cell or a single battery
    • H01M50/102—Primary casings, jackets or wrappings of a single cell or a single battery characterised by their shape or physical structure
    • H01M50/103—Primary casings, jackets or wrappings of a single cell or a single battery characterised by their shape or physical structure prismatic or rectangular
    • 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
    • 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
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • 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
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • 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 sealed battery in which an electrolytic solution and an electrode body are enclosed in a battery case, and a manufacturing method thereof.
  • lithium ions as disclosed in JP 2006-202647 A, JP 2004-047404 A, and JP 2005-259697 A Secondary batteries are known.
  • the positive electrode active material is a lithium-containing composite oxide containing nickel
  • the negative electrode active material is a material that can be alloyed with lithium such as silicon oxide.
  • a high-capacity lithium ion secondary battery can be obtained by combining active materials made of these materials.
  • the lithium-containing composite oxide containing nickel generates carbon dioxide gas or the like when the synthesis-derived impurities such as lithium carbonate, lithium hydrogen carbonate, and lithium hydroxide are decomposed.
  • Silicon oxide has a large volume change due to a chemical reaction during charge and discharge. Therefore, the particles in the silicon oxide are pulverized for each charge / discharge cycle of the battery. As a result, the silicon deposited on the surface reacts with the solvent of the non-aqueous electrolyte, and gas is generated in the battery.
  • the pressure in the battery case increases, which may cause deformation of the battery case.
  • wide capacity batteries with a high capacity and a small thickness are often used in mobile phones and the like. Therefore, the pressure change in the battery case is likely to occur, and the battery case is likely to be deformed by the pressure change in the battery case.
  • a sealed battery includes an electrode body having a positive electrode and a negative electrode, an electrolytic solution, and a battery case in which the electrode body and the electrolytic solution are enclosed.
  • a lithium-containing composite oxide containing lithium and a transition metal is used as a positive electrode active material. At least a part of the lithium-containing composite oxide contains nickel as a transition metal.
  • the negative electrode includes, as a negative electrode active material, a material containing Si and O as constituent elements (however, an atomic ratio x of O to Si is 0.5 ⁇ x ⁇ 1.5) and a graphitic carbon material.
  • the electrolytic solution contains a phosphonoacetate compound.
  • On the side surface of the battery case a concave portion that is recessed toward the inside of the battery case is formed (first configuration).
  • the phosphonoacetate compound controls the reaction between the negative electrode active material containing a material containing Si and O as a constituent element and the electrolyte, and generates gas. Can be suppressed.
  • the battery case can be prevented from being deformed even when the pressure in the battery case rises by providing the battery case with a concave portion recessed inwardly on the side surface of the battery case. it can.
  • the phosphonoacetate compound is preferably a compound having a triple bond in R 3 of the following general formula (1) (second configuration).
  • R 1 to R 3 each independently represents an alkyl group, alkenyl group or alkynyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom.
  • n represents an integer of 0 to 6.
  • the reaction between the negative electrode active material containing a material containing Si and O as a constituent element and the electrolytic solution is more reliably suppressed. be able to. Therefore, deformation of the battery case due to gas generation in the battery case can be more reliably suppressed.
  • the phosphonoacetate compound is preferably a compound in which R 3 in the general formula (1) is a propynyl group (third configuration).
  • the phosphonoacetate compound is preferably 2-propynyl 2- (diethoxyphosphoryl) acetate (fourth configuration).
  • the porous insulating layer provided on the electrode body mainly has a function of reducing capacity deterioration in repeated charge / discharge cycles.
  • the generation of gas and the deformation of the battery case are suppressed as described above, so that the pressing of the electrode body by the battery case is loosened. Can be suppressed.
  • the side surface of the battery case has at least one corner portion, and the concave portion extends from the corner portion of the side surface of the battery case. It is preferable to arrange on a straight line extending to the central portion of the side surface (sixth configuration).
  • the rigidity of the side surface of the battery case can be partially increased, and deformation of the side surface of the battery case is suppressed. be able to.
  • the recess is not formed on the center portion of the side surface where deformation is likely to occur, but is formed on a straight line extending from the corner portion of the side surface of the battery case to the center portion, the shape of the recess is formed even if the battery case is slightly deformed. Can be maintained. Thereby, even when the internal pressure of the battery case is increased, deformation of the side surface of the battery case can be suppressed.
  • ridgelines extending from the four corners to the central part are formed on the rectangular side surface of the battery case.
  • the concave portion is disposed in at least one of the four corners of the side surface of the battery case, formation of the ridge line is hindered, resulting in deformation of the side surface of the battery case. Can be suppressed.
  • the battery case has at least a pair of opposing side surfaces, and the recess is formed on each of the pair of side surfaces of the battery case (eighth configuration). ).
  • each of the pair of opposing side surfaces By forming a recess on each of the pair of opposing side surfaces, the deformation of each of the pair of side surfaces can be suppressed, and as a result, the deformation of the entire battery case can be more reliably suppressed.
  • the recess is preferably formed in a polygonal shape when viewed from the normal direction of the side surface of the battery case (9th configuration). .
  • the recess since the recess has a plurality of recess side surfaces, deformation of the side surface of the battery case can be suppressed in a plurality of directions by the plurality of recess side surfaces. Moreover, since the recess has a plurality of corner portions, the rigidity of the side surface of the battery case can be increased in a plurality of directions also by the corner portions. Thereby, the deformation
  • the corner portion of the recess is preferably located on a straight line extending from the corner portion of the side surface of the battery case to the central portion of the side surface of the battery case (tenth configuration).
  • the battery case can be prevented from being deformed by the corners of the polygonal recesses. That is, in the concave portion, the rigidity is highest at the corner portion of the concave portion. Therefore, on the side surface of the battery case, the shape of the concave portion can be more reliably maintained by arranging the corner portion of the concave portion on a straight line extending from the corner portion to the central portion instead of the central portion that easily deforms. As a result, deformation of the side surface of the battery case can be more reliably suppressed.
  • a manufacturing method of a sealed battery includes a step of preparing a bottomed cylindrical outer can having a recess on a side surface, and a positive electrode active material layer containing a lithium-containing composite oxide.
  • forming a negative electrode active material layer on the negative electrode current collector producing a negative electrode, producing an electrode body having the positive electrode and the negative electrode, and inserting the electrode body into the outer can
  • the lithium-containing composite oxide contains nickel as a transition metal (first method).
  • the deformation of the outer can is suppressed by the concave portion on the side surface of the outer can.
  • a sealed battery in which the outer can is difficult to deform can be manufactured.
  • the phosphonoacetate compound is preferably a compound having a triple bond in R 3 of the general formula (1) (second method).
  • the phosphonoacetate compound is preferably a compound in which R 3 in the general formula (1) is a propynyl group (third method).
  • the phosphonoacetate compound is preferably 2-propynyl 2- (diethoxyphosphoryl) acetate (fourth method).
  • Any one of the first to fourth methods includes a step of forming a porous insulating layer on at least one main surface of the positive electrode and the negative electrode and / or on the opposite surface of the main surface; May be further provided (fifth method).
  • FIG. 1 is a perspective view showing a schematic configuration of a sealed battery according to an embodiment of the present invention.
  • 2 is a cross-sectional view taken along line II-II in FIG.
  • FIG. 3 is a side view showing a schematic configuration of the sealed battery.
  • 4 is a cross-sectional view of the battery case taken along line IV-IV in FIG.
  • FIG. 5 is a view corresponding to FIG. 1 and showing an example of a recess having another shape.
  • FIG. 6 is a view corresponding to FIG. 1 showing a state after the fragile portion is cleaved in the sealed battery.
  • FIG. 7A is a diagram illustrating a part of a vertical cross section of a positive electrode in a sealed battery.
  • FIG. 7B is a diagram showing a part of a vertical cross section of a positive electrode different from FIG. 7A.
  • FIG. 8A is a diagram showing a part of a vertical cross section of a negative electrode in a sealed battery.
  • FIG. 8B is a diagram showing a part of a vertical cross section of a negative electrode different from FIG. 8A.
  • FIG. 9 is a flowchart showing a method for manufacturing a sealed battery according to an embodiment of the present invention.
  • FIG. 10 is a flowchart showing another method for manufacturing a sealed battery according to an embodiment of the present invention.
  • FIG. 1 is a perspective view showing a schematic configuration of a sealed battery 1 according to an embodiment of the present invention.
  • the sealed battery 1 includes a bottomed cylindrical outer can 10, a cover plate 20 that covers an opening of the outer can 10, and an electrode body 30 that is accommodated in the outer can 10.
  • the cover plate 20 By attaching the cover plate 20 to the outer can 10, the columnar battery case 2 having a space inside is formed.
  • a non-aqueous electrolyte hereinafter also simply referred to as an electrolyte
  • an electrolyte is enclosed in the battery case 2.
  • the outer can 10 is a bottomed cylindrical member made of an aluminum alloy, and constitutes the battery case 2 together with the cover plate 20. As shown in FIG. 1, the outer can 10 is a bottomed cylindrical member having a bottom surface 11 in which a rectangular short side is formed in an arc shape. Specifically, the outer can 10 includes a bottom surface 11 and a flat cylindrical side wall 12 having a smooth curved surface. The side wall 12 has a pair of rectangular portions (rectangular shapes in the present embodiment) disposed opposite to each other, and a semicylindrical semicylindrical portion 14 that connects the pair of planar portions 13 to each other.
  • the outer can 10 is formed in a flat shape such that the dimension in the thickness direction corresponding to the short side direction of the bottom surface 11 is smaller than the width direction corresponding to the long side direction of the bottom surface 11. Further, since the outer can 10 is joined to the lid plate 20 connected to the positive electrode lead 34 as will be described later, it also serves as the positive electrode terminal of the sealed battery 1.
  • An insulator 15 made of is arranged.
  • the electrode body 30 is disposed on the insulator 15 so that one end thereof is positioned.
  • the cover plate 20 is joined to the opening of the outer can 10 by welding so as to cover the opening of the outer can 10.
  • the cover plate 20 is made of an aluminum alloy member, like the outer can 10, and has a rectangular short side formed in an arc shape so as to fit inside the opening of the outer can 10.
  • the through-hole is formed in the center part of the longitudinal direction in the cover board 20.
  • An insulating packing 21 made of polypropylene and a negative electrode terminal 22 made of stainless steel are inserted into the through hole.
  • a substantially cylindrical insulating packing 21 into which a substantially columnar negative electrode terminal 22 is inserted is fitted to the peripheral portion of the through hole.
  • the negative electrode terminal 22 has a configuration in which flat portions are integrally formed at both ends of a cylindrical shaft portion.
  • the negative electrode terminal 22 is disposed with respect to the insulating packing 21 so that the flat surface portion is exposed to the outside and the shaft portion is positioned in the insulating packing 21.
  • a stainless steel lead plate 27 is connected to the negative terminal 22.
  • the negative electrode terminal 22 is electrically connected to the negative electrode 32 of the electrode body 30 via the lead plate 27 and the negative electrode lead 35.
  • An insulator 26 is disposed between the lead plate 27 and the insulating packing 21.
  • the lid plate 20 is formed with an electrolyte inlet 24 along with the negative electrode terminal 22.
  • the injection port 24 is formed in a substantially circular shape in plan view.
  • the injection port 24 has a small diameter portion and a large diameter portion so that the diameter changes in two steps in the thickness direction of the lid plate 20.
  • the injection port 24 is sealed by a sealing plug 25 formed in a step shape corresponding to a change in the diameter of the injection port 24.
  • the flat outer peripheral portion of the sealing plug 25 and the peripheral portion of the injection port 24 are laser-welded so that no gap is generated between the sealing plug 25 and the peripheral portion of the injection port 24. Be joined. Thereby, the outer can 10 containing the electrode body 30 and the electrolytic solution is sealed.
  • the electrode body 30 has a positive electrode 31 and a negative electrode 32 formed in a sheet shape, for example, in a state where the separators 33 are positioned between them and below the negative electrode 32, respectively. It is the winding electrode body formed by winding in a spiral shape.
  • the electrode body 30 is formed in a flat shape after being wound in a state where the positive electrode 31, the negative electrode 32, and the separator 33 are overlapped with each other.
  • the positive electrode 31 is obtained by providing positive electrode active material layers containing a positive electrode active material on both surfaces of a positive electrode current collector made of a metal foil such as aluminum.
  • the positive electrode 31 has a positive electrode active material that is a lithium-containing oxide capable of inserting and extracting lithium ions, a conductive additive, a positive electrode mixture including a binder, and the like on a positive electrode current collector made of an aluminum foil or the like. It is formed by applying and drying.
  • the positive electrode active material layer may be formed on the positive electrode current collector by a method other than coating, such as transfer.
  • a well-known material can be used as a conductive support agent and a binder.
  • the conductive auxiliary can include a carbon material such as carbon black
  • the binder can include an organic solvent binder such as polyvinylidene fluoride (PVdF).
  • a lithium-containing composite oxide containing lithium and a transition metal is used as the positive electrode active material.
  • a plurality of types of lithium-containing composite oxides may be used as the positive electrode active material.
  • the lithium-containing composite oxide include lithium cobalt oxides such as LiCoO 2 , lithium manganese oxides such as LiMn 2 O 4 , lithium nickel oxides such as LiNiO 2, and the like.
  • at least a part of the lithium-containing composite oxide contains nickel as a transition metal.
  • the lithium-containing composite oxide containing nickel as a transition metal contains at least nickel as a transition metal element constituting the composite oxide, and includes cobalt, manganese, titanium, chromium, iron, copper, silver, tantalum, niobium, Other transition metals such as zirconium may be contained as a constituent element.
  • the lithium-containing composite oxide containing nickel as a transition metal may contain elements other than transition metal elements such as boron, phosphorus, zinc, aluminum, calcium, strontium, barium, germanium, tin, and magnesium. .
  • Lithium-containing composite oxides include Li-containing compounds (such as lithium hydroxide monohydrate), Ni-containing compounds (such as nickel sulfate), Co-containing compounds (such as cobalt sulfate), and Mn-containing compounds (such as manganese sulfate). It can be manufactured by mixing and baking.
  • the firing conditions can be, for example, 800 to 1050 ° C. for 1 to 24 hours, but once heated to a temperature lower than the firing temperature (for example, 250 to 850 ° C.) and maintained at that temperature, preheating is performed. After that, it is preferable to raise the temperature to the firing temperature to advance the reaction. There is no particular limitation on the preheating time, but it is usually about 0.5 to 30 hours.
  • the atmosphere during firing can be an atmosphere containing oxygen (that is, in the air), a mixed atmosphere of an inert gas (such as argon, helium, or nitrogen) and oxygen gas, or an oxygen gas atmosphere.
  • the oxygen concentration (volume basis) is preferably 15% or more, and more preferably 18% or more. *
  • negative electrode active material layers containing a negative electrode active material are provided on both sides of a negative electrode current collector made of a metal foil such as copper.
  • the negative electrode 32 is formed by applying and drying a negative electrode mixture containing a negative electrode active material capable of occluding and releasing lithium ions, a conductive additive, a binder, and the like on a negative electrode current collector made of copper foil or the like. Formed by.
  • the negative electrode active material layer may be formed on the negative electrode current collector by a method other than coating, such as transfer.
  • a well-known material can be used as a conductive support agent and a binder.
  • SiO x may contain a microcrystalline or amorphous phase of Si.
  • the atomic ratio between Si and O is a ratio in which Si includes microcrystalline Si and amorphous phase Si. That is, SiO x includes a structure in which Si (for example, microcrystalline Si) is dispersed in an amorphous SiO 2 matrix. Therefore, it is sufficient that the above-mentioned atomic ratio x satisfies 0.5 ⁇ x ⁇ 1.5 by combining amorphous SiO 2 and Si dispersed therein.
  • SiO x and the carbon material are combined to form a composite.
  • the surface of SiO x is desirably covered with a carbon material.
  • SiO x has poor conductivity. Therefore, when using SiO x as the negative electrode active material, mixing and dispersion of SiO x and the conductive material in the negative electrode using a conductive material (conductive aid) from the viewpoint of ensuring good battery characteristics. Must be in good condition to form an excellent conductive network.
  • a conductive material conductive aid
  • the ratio of SiO x to the carbon material is 100 parts by mass with respect to 100 parts by mass of SiO x in order to sufficiently obtain the effect of the composite with the carbon material.
  • the carbon material is preferably 5 parts by mass or more, and more preferably 10 parts by mass or more. Further, in the composite, if the ratio of the carbon material to be composited with SiO x is too high, the amount of SiO x in the negative electrode mixture layer is reduced, so that the effect of increasing the capacity of the battery may be reduced. . Therefore, with respect to 100 parts by weight of SiO x, it is preferred that the carbon material is less than 50 parts by mass, more preferably not more than 40 parts by mass.
  • SiO x is obtained by a method of heating a mixture of Si and SiO 2 and cooling and depositing the generated silicon oxide gas. Furthermore, by heat-treating the obtained SiO x under an inert gas atmosphere, a fine Si phase can be formed inside the particles. By adjusting the heat treatment temperature and time at this time, the half width of the (111) diffraction peak of the formed Si phase can be controlled.
  • the heat treatment temperature is set in the range of about 900 to 1400 ° C.
  • the heat treatment time may be set in the range of about 0.1 to 10 hours.
  • SiO x particles examples include, as described above, SiO x primary particles, SiO x composite particles, and granulated bodies of SiO x and a carbon material. Hereinafter, these are collectively referred to as “SiO x particles”. Also called.
  • the SiO x composite particles can be obtained, for example, by preparing a dispersion liquid in which SiO x is dispersed in a dispersion medium, and spraying and drying the dispersion liquid.
  • a dispersion liquid in which SiO x is dispersed in a dispersion medium
  • spraying and drying the dispersion liquid For example, ethanol or the like can be used as the dispersion medium. It is appropriate to spray the dispersion liquid in an atmosphere of 50 to 300 ° C.
  • the SiO x can be obtained by granulating together with the carbon material.
  • SiO x composite particles or granulated body of SiO x and carbon material carbon produced by thermal decomposition of hydrocarbon gas by heating SiO x particles (SiO x composite particles or granulated body of SiO x and carbon material) and hydrocarbon gas in a gas phase. Is deposited on the surface of the SiO x particles to produce a composite of SiO x and a carbon material.
  • the hydrocarbon-based gas spreads to every corner of the composite particle, and the surface of the particle and the pores in the surface are thin and contain a conductive carbon material. Since a uniform film, that is, a carbon coating layer can be formed, it is possible to uniformly impart conductivity to the SiO x particles with a small amount of carbon material.
  • the processing temperature (atmospheric temperature) of the vapor deposition (CVD) method varies depending on the type of hydrocarbon gas, but is usually 600 to 1200 ° C., preferably 700 ° C. or higher. More preferably, it is 800 ° C. or higher. This is because the higher the treatment temperature, the less the remaining impurities, and the formation of a coating layer containing carbon having high conductivity.
  • toluene As the liquid source of the hydrocarbon-based gas, toluene, benzene, xylene, mesitylene and the like can be used, but toluene that is easy to handle is particularly preferable.
  • a hydrocarbon-based gas can be obtained by vaporizing them (for example, bubbling with nitrogen gas).
  • methane gas, acetylene gas, etc. can also be used.
  • SiO x particles SiO x composite particles or a granulated body of SiO x and a carbon material
  • a carbon material by a vapor deposition (CVD) method
  • a petroleum-based pitch or a coal-based pitch is used.
  • At least one organic compound selected from the group consisting of a thermosetting resin and a condensate of naphthalene sulfonate and aldehydes is attached to a coating layer containing a carbon material, and then the organic compound is attached.
  • the obtained particles may be fired.
  • a dispersion liquid is prepared in which SiO x particles (SiO x composite particles or a granulated body of SiO x and a carbon material) whose surface is coated with a carbon material and the organic compound are dispersed in a dispersion medium.
  • the dispersion is sprayed and dried to form particles coated with the organic compound, and the particles coated with the organic compound are fired.
  • an isotropic pitch can be used.
  • thermosetting resin phenol resin, furan resin, furfural resin, or the like can be used.
  • condensate of naphthalene sulfonate and aldehydes naphthalene sulfonic acid formaldehyde condensate can be used.
  • Examples of the dispersion medium for dispersing the organic compound with SiO x particles (SiO x composite particles or a granulated body of SiO x and a carbon material) whose surface is coated with a carbon material include, for example, water and alcohols (Ethanol etc.) can be used. It is appropriate to spray the dispersion liquid in an atmosphere of 50 to 300 ° C.
  • the firing temperature is usually 600 to 1200 ° C., preferably 700 ° C. or higher, and more preferably 800 ° C. or higher. This is because the higher the processing temperature, the less the remaining impurities, and the formation of a coating layer containing a high-quality carbon material with high conductivity. However, the processing temperature needs to be lower than the melting point of SiO x .
  • Examples of the graphitic carbon material used as the negative electrode active material together with the composite of SiO x and the carbon material include natural graphite such as flake graphite, pyrolytic carbons or graphitizable carbon such as MCMB and carbon fiber, 2800. Examples thereof include artificial graphite that has been graphitized at a temperature of at least ° C.
  • the content of the negative electrode active material in complex with SiO x and the carbon material is not less than 0.01 wt% Is preferable, and it is more preferable that it is 3 mass% or more. Further, from the viewpoint of better avoiding the problem due to the volume change of SiO x accompanying charge / discharge, the content of the composite in the negative electrode active material is preferably 20% by mass or less, and preferably 10% by mass or less. More preferably.
  • SiO x Material containing Si and O as constituent elements (however, the atomic ratio x of O to Si is 0.5 ⁇ x ⁇ 1.5.
  • the material is also referred to as “SiO x ”) and graphitic carbon Contains materials.
  • a positive electrode lead 34 is connected to the positive electrode 31 of the electrode body 30, while a negative electrode lead 35 is connected to the negative electrode 32.
  • the positive electrode lead 34 and the negative electrode lead 35 are drawn out of the electrode body 30.
  • the tip end side of the positive electrode lead 34 is connected to the lid plate 20.
  • the distal end side of the negative electrode lead 35 is connected to the negative electrode terminal 22 via a lead plate 27 as described later.
  • the separator 33 is a polyolefin porous film made of, for example, polyethylene or polypropylene. This polyolefin porous film is generally used for lithium secondary batteries.
  • the melting point of polyethylene is approximately 130 ° C. Therefore, when a polyethylene porous membrane is used as the separator, if the temperature inside the battery exceeds 130 ° C., the separator may melt and contract, and a short circuit may occur between the positive electrode and the negative electrode. Therefore, in order to improve safety in a high temperature environment, it is preferable to use a separator in which, for example, a heat resistant resin or a heat resistant inorganic filler is laminated.
  • a laminated separator having a porous layer (I) mainly composed of a thermoplastic resin and a porous layer (II) mainly composed of a filler having a heat resistant temperature of 150 ° C. or higher. This is because such a separator has high shutdown characteristics and heat shrinkage resistance.
  • the electrolytic solution is prepared by dissolving a lithium salt and a phosphonoacetate compound satisfying the following general formula (1) in an organic solvent. That is, the electrolytic solution contains a phosphonoacetate compound that satisfies the following general formula (1).
  • R 1 to R 3 each independently represents an alkyl group, alkenyl group or alkynyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom.
  • n represents an integer of 0 to 6.
  • phosphonoacetate compounds represented by the general formula (1) triethylphosphonoacetate, allyldiethylphosphonoacetate, 2-propynyldimethylphosphonoacetate, 2-propynyl-2- (diethoxyphosphoryl) acetate and the like preferable.
  • R 3 is preferably a propynyl group or a nitrile group.
  • the electrolyte used in the battery includes, for example, vinylene carbonate (VC), fluoroethylene carbonate (FEC), acid anhydride, sulfonate ester, dinitrile, 1,3-propane sultone, diphenyl disulfide, cyclohexylbenzene, biphenyl, Additives (including these derivatives) such as fluorobenzene, t-butylbenzene, succinonitrile and the like are appropriately added.
  • the additive is selected in accordance with required characteristics such as cycle characteristics, safety improvement such as suppression of high-temperature blistering and prevention of overcharge.
  • the conventional additives as described above improve the high-temperature storage property and suppress the swelling of the battery, the characteristics of the battery charge / discharge cycle are often deteriorated. This is because even when the addition amount is small, conventional additives such as 1,3-propane sultone and succinonitrile react with other than the active site of the positive electrode active material, and the reaction product is deposited. This is considered to result in a decrease and an increase in resistance.
  • the inventors have used a lithium composite oxide containing nickel as a positive electrode active material, and when the electrolyte contains a phosphonoacetate compound, the characteristics of the charge / discharge cycle It has been found that the high temperature storage property can be improved and the swelling of the battery can be suppressed without deteriorating the battery. This is presumed to be because the phosphonoacetate compound covers the active sites of nickel that reacts with the electrolyte to generate gas.
  • a film is formed on the negative electrode by the phosphonoacetate compound at the first charge / discharge after the battery is produced, but the film by the phosphonoacetate compound has high thermal stability and low resistance. Therefore, it is considered that the coating is difficult to decompose even under high temperature storage, and the increase in resistance is suppressed.
  • the electrolyte contains 0.5% by mass or more of these phosphonoacetate compounds in a non-aqueous electrolyte used in a battery (non-aqueous electrolyte used in battery assembly, the same applies hereinafter). It is preferable that it is 1 mass% or more. If the amount of the phosphonoacetate compound in the non-aqueous electrolyte is too small, the effect of suppressing gas generation can be obtained to some extent, but the active point of nickel cannot be sufficiently covered, and the effect of suppressing battery swelling Decreases.
  • the phosphonoacetate compound is preferably 5% by mass or less, more preferably 3% by mass or less, in the nonaqueous electrolytic solution used for battery assembly.
  • additives such as vinylene carbonate, fluoroethylene carbonate, anhydride, sulfonic acid ester, dinitrile, 1,3-propane sultone, diphenyl disulfide, cyclohexyl benzene, biphenyl, fluorobenzene, t-butyl benzene, etc.
  • Additives may be used in combination as appropriate depending on the desired battery characteristics.
  • non-aqueous electrolyte it is preferable to use a non-aqueous electrolyte containing a halogen-substituted cyclic carbonate (for example, fluoroethylene carbonate) and vinylene carbonate.
  • a halogen-substituted cyclic carbonate for example, fluoroethylene carbonate
  • vinylene carbonate for example, vinylene carbonate
  • halogen-substituted cyclic carbonate a compound represented by the following general formula (2) can be used.
  • R 4 , R 5 , R 6 and R 7 represent hydrogen, a halogen element or an alkyl group having 1 to 10 carbon atoms, and a part or all of hydrogen of the alkyl group is halogen. It may be substituted with an element. At least one of R 4 , R 5 , R 6 and R 7 is a halogen element. R 4 , R 5 , R 6 and R 7 may be different from each other, or two or more may be the same. When R 4 , R 5 , R 6 and R 7 are alkyl groups, the smaller the number of carbon atoms, the better. As the halogen element, fluorine is particularly preferable.
  • FEC 4-fluoro-1,3-dioxolan-2-one
  • the content of the halogen-substituted cyclic carbonate is preferably 1% by mass or more, and the content of VC is preferably 1% by mass or more.
  • the halogen-substituted cyclic carbonate content is more preferably 1.5% by mass or more, and the VC content is more preferably 1.5% by mass or more.
  • the content of the halogen-substituted cyclic carbonate and VC of the non-aqueous electrolyte is too large, if the SiO x is contained in the anode active material, decreases the activity of SiO x or, in the film-forming At this time, excessive gas may be generated, which may cause the battery case to swell. Therefore, in the non-aqueous electrolyte used for the battery, the content of the halogen-substituted cyclic carbonate is preferably 10% by mass or less, and the content of VC is preferably 10% by mass or less.
  • the halogen-substituted cyclic carbonate content is more preferably 5% by mass or less, and the VC content is more preferably 5% by mass or less.
  • the lithium salt used in the non-aqueous electrolyte is not particularly limited as long as it dissociates in a solvent to form lithium ions and does not easily cause side reactions such as decomposition in a voltage range used as a battery.
  • a lithium salt LiClO 4 , LiPF 6 , LiBF 4 , LiAsF 6 , LiSbF 6 and other inorganic lithium salts, LiCF 3 SO 3 , LiCF 3 CO 2 , Li 2 C 2 F 4 (SO 3 ) 2 , LiN ( Organic lithium salts such as CF 3 SO 2 ) 2 , LiC (CF 3 SO 2 ) 3 , LiC n F 2n + 1 SO 3 (n ⁇ 2), LiN (RfOSO 2 ) 2 [where Rf is a fluoroalkyl group] Can be used.
  • the concentration of the lithium salt in the non-aqueous electrolyte is preferably 0.5 to 1.5 mol / l, more preferably 0.9 to 1.25 mol / l.
  • the organic solvent used in the non-aqueous electrolyte is not particularly limited as long as it can dissolve the lithium salt and does not cause a side reaction such as decomposition in a voltage range used as a battery.
  • organic solvents include cyclic carbonates such as ethylene carbonate, propylene carbonate, and butylene carbonate; chain carbonates such as dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate; chain esters such as methyl propionate; cyclic esters such as ⁇ -butyrolactone.
  • Chain ethers such as dimethoxyethane, diethyl ether, 1,3-dioxolane, diglyme, triglyme and tetraglyme; cyclic ethers such as dioxane, tetrahydrofuran and 2-methyltetrahydrofuran; acetonitrile, propionitrile, methoxypropionitrile and the like; Nitriles; sulfites such as ethylene glycol sulfite; and the like.
  • solvents can be used in a mixture of two or more. In order to obtain a battery having better characteristics, it is desirable to use a combination of solvents such as a mixed solvent of ethylene carbonate and chain carbonate that can provide high conductivity.
  • a plurality of recesses 41 are formed in the flat portion 13 of the side wall 12 of the outer can 10. If the recessed part 41 is provided in the plane part 13, there will be no restriction
  • angular parts of a pair of plane part 13 of the armored can 10 can be considered.
  • the concave portion 41 does not have to be formed in all four corner portions of the plane portion 13, and can be formed in at least one of the four corner portions of the plane portion 13.
  • FIGS. 1 and 3 will be described in detail.
  • the recess 41 is formed in a quadrangular shape (in this embodiment, a square shape) when viewed from the normal direction of the flat surface portion 13.
  • the recess 41 has a rectangular bottom surface portion 41a and four side wall portions 41b (recess side surfaces) extending toward the inner side of the battery case 2 corresponding to the respective sides of the bottom surface portion 41a.
  • the recessed part 41 is formed in this plane part 13 so that the four side wall parts 41b may become substantially parallel with respect to the four sides of the plane part 13 of the armored can 10 (refer FIG. 3).
  • the recess 41 may have a quadrangular shape other than a square, such as a rectangle or a parallelogram, or another polygonal shape such as a triangle or a pentagon when viewed from the normal direction of the flat surface portion 13. Further, the concave portion 41 may be circular or elliptical when viewed from the normal direction of the plane portion 13.
  • the recessed part 41 is arrange
  • the straight line L extends along the diagonal line of the plane portion 13.
  • the concave portion 41 is provided on the flat surface portion 13 of the outer can 10 so that a corner portion 41c to which the two side wall portions 41b are connected is positioned on the straight line L.
  • deformation of the battery case 2 can be suppressed.
  • deformation in two directions with respect to the straight line L can be suppressed by the two side wall portions 41b constituting the corner portion 41c.
  • the straight line L coincides with the ridgeline formed on the outer can 10 when the battery case 2 swells as the internal pressure of the sealed battery 1 increases.
  • ridge lines extending from each corner portion of the plane portion 13 are connected.
  • the recessed part 41 since the recessed part 41 is formed in each corner
  • the concave portion 41 is formed on the straight line L so that the corner portion 41c is positioned on the corner portion side of the plane portion 13 in the straight line L.
  • the recessed part 41 may be provided so that the side wall part 41b may be located on the straight line L.
  • the effect as in the case where the corner portion 41c of the concave portion 41 is arranged on the straight line L cannot be expected, but the deformation of the battery case 2 can be suppressed by the side wall portion 41b.
  • the concave portions 41 are formed at positions facing each other in the pair of flat surface portions 13 of the outer can 10. That is, FIG. 3 shows only one flat portion 13, but the other flat portion 13 is also formed with a concave portion 41 at the same position as the concave portion 41 formed in the one flat portion 13. Thereby, since a deformation
  • the concave portion 41 is formed by pressing together with the outer can 10 when the outer can 10 is press-molded. Therefore, as shown in a cross section in FIG. 4, the side wall 41 b of the recess 41 is inclined so that the recess 41 expands outward from the bottom surface 41 a of the recess 41 toward the opening side.
  • work hardening occurs in the peripheral portions of the bottom surface portion 41a and the side wall portion 41b constituting the concave portion 41, so that the strength of the peripheral portion of the concave portion 41 can be improved. Therefore, the deformation of the battery case 2 can be more reliably suppressed by the recess 41.
  • the concave portion 41 will be described in detail later, it is preferable that the flat portion 13 is formed at the end that can be press-molded among the end portions. Moreover, it is preferable that the recessed part 41 has the steepest inclination of the side wall part 41b in the angle which can be press-molded. Furthermore, it is preferable that the depth of the recess 41 is as deep as possible within a range that does not hinder the functions of the electrode body 30 and the like housed in the battery case 2.
  • a vent mechanism for releasing the internal pressure when the internal pressure of the battery abnormally increases.
  • the internal pressure of the battery may increase instantaneously. At that time, by operating the vent mechanism, the gas in the battery is released to reduce the internal pressure.
  • a vent mechanism for reducing the internal pressure of the battery for example, there is a fragile portion 51 having a low welding strength provided in the welded portion 50 between the outer can 10 and the cover plate 20 (see FIG. 6).
  • the fragile portion 51 is cleaved when the internal pressure of the battery rises and releases the gas in the battery to the outside of the battery, thereby preventing the internal pressure of the battery from increasing.
  • the fragile portion 51 is provided in at least one end in the width direction of the battery case 2, that is, in the longitudinal direction of the lid plate 20. Further, the fragile portion 51 is provided on at least one side in the thickness direction of the battery case 2, that is, the short side direction of the lid plate 20. In the case of FIG. 6, one fragile portion 51 is provided on the back side (the back side of the drawing) of the left side (the left side of the drawing) of the battery case 2.
  • the weld 50 is welded by laser welding or resistance welding.
  • the fragile portion 51 is formed by narrowing the weld bead width or reducing the penetration depth during welding.
  • the weakened portion 51 can be formed by making the irradiation output of the laser beam smaller than other portions of the welded portion 50 or shortening the irradiation time.
  • vent mechanisms include, for example, a configuration in which a cleaving groove that is cleaved when the internal pressure of the battery rises is provided in the lid plate 20 or a side surface of the outer can 10.
  • the shape of the cleavage groove may be any shape as long as it can be cleaved according to the internal pressure of the battery, such as a linear shape, an arc shape, an S shape, and a horseshoe iron shape.
  • a plurality of vent mechanisms may be provided.
  • a porous insulating layer may be formed on the surface of at least one of the positive electrode 31 and the negative electrode 32. It is known that when a filler such as alumina is laminated on at least one surface of the positive electrode and the negative electrode as a porous insulating layer, the safety of the battery is improved and the capacity deterioration is relatively reduced in repeated charge / discharge cycles. It has been. However, due to gas generation due to repeated charge / discharge cycles and expansion / contraction of the electrode, the outer can may swell, the electrode body may be loosely pressed, and the porous insulating layer may fall off the electrode. When the porous insulating layer is detached from the electrode, there is a problem that the above-described original function is remarkably impaired.
  • the generation of gas is suppressed by the action of the phosphonoacetates contained in the electrolytic solution described above, and the presence of a plurality of recesses 41 formed in the flat portion 13 of the side wall 12 of the outer can 10.
  • the swelling of the outer can is suppressed, it is possible to solve the problem of the prior art in which the porous insulating layer is dropped from the electrode.
  • a porous insulating layer 31c is formed on the surface 311 of each of the positive electrode active material layers 31b formed on both surfaces of the positive electrode current collector 31a.
  • the porous insulating layer 31c may be formed on the surface 311 of one of the positive electrode active material layers 31b formed on both surfaces of the positive electrode current collector 31a.
  • the surface 311 of one positive electrode active material layer 31b is the main surface of the positive electrode 31, and the other positive electrode
  • the surface 311 of the active material layer 31 b corresponds to a surface facing the main surface of the positive electrode 31.
  • the porous insulating layer 31c is made of, for example, a paste-like or slurry-like porous insulation in which a filler as a base material and a binder, a thickener, a dispersant, etc. are dispersed in a solvent such as water or NMP as necessary. It is formed by preparing a layer-containing composition, applying it to the surface of the positive electrode active material layer 31b, and drying it.
  • the filler used for the porous insulating layer 31c is not particularly limited as long as it has electrical insulating properties and is electrochemically stable, and may be an inorganic material or an organic material. Among these, it is desirable to contain a filler having a heat resistant temperature of 150 ° C. or higher.
  • the heat resistant temperature is 150 ° C. or higher” means that deformation such as softening is not observed at least at 150 ° C.
  • the separator melts and contracts, which may cause a short circuit between the positive electrode and the negative electrode. Therefore, by including a filler having a heat resistant temperature of 150 ° C.
  • porous insulating layer 31c even if the separator melts and contracts, at least one main surface of the positive electrode 31 and the negative electrode 32 and / or the opposing surface thereof.
  • the presence of the porous insulating layers 31c and 32c formed on the surface can prevent a short circuit between the positive electrode and the negative electrode.
  • the inorganic material includes, for example, magnesium, aluminum, silicon, calcium, zirconium, barium, and the like, which are mainly composed of elements in the third to sixth periods in the periodic table of elements.
  • the organic material include acrylate-based resins, cross-linked polystyrene, polyimide, melamine resins, and phenol resins. These inorganic materials and organic materials may be used alone or in combination of two or more.
  • the porous insulating layer 32c is formed on the surface 321 of each of the negative electrode active material layers 32b formed on both surfaces of the negative electrode current collector 32a.
  • the porous insulating layer 32c may be formed on the surface 321 of one of the negative electrode active material layers 32b among the negative electrode active material layers 32b formed on both surfaces of the negative electrode current collector 32a.
  • the surface 321 of one negative electrode active material layer 32b is the main surface of the negative electrode 32, and the other negative electrode
  • the surface 321 of the active material layer 32 b corresponds to a surface facing the main surface of the negative electrode 32.
  • the porous insulating layer 32c can be formed by the same method as that for forming the positive electrode porous insulating layer 31c.
  • the material constituting the porous insulating layer 32c such as the filler and the binder, is not necessarily the same as the porous insulating layer 31c.
  • a filler different from the filler used in the porous insulating layer 31c is used. You may use for the porous insulating layer 32c.
  • the outer can 10 having the concave portion 41 (61) on the side surface is prepared (step S1).
  • a bottomed cylindrical outer can 10 is manufactured by using the metal such as aluminum as a raw material by the above press molding or the like.
  • the outer can 1 by press molding, as described above, it is preferable to simultaneously form the recess 41 (61) on the side surface of the outer can 10 by pressing.
  • a bottomed cylindrical outer can 10 having a recess on the side surface of the can and the recess 41 (61) on the side surface. can also be produced.
  • the insulator 15 (see FIG. 2) described above may be disposed on the bottom surface in the outer can 10.
  • the positive electrode 31 is produced by the method described above (step S2).
  • a positive electrode lead 34 is connected to the manufactured positive electrode 31.
  • the negative electrode 32 is produced by the method described above (step S3).
  • a negative electrode lead 35 is connected to the manufactured negative electrode 35.
  • step S1 the order in which the outer can is prepared (step S1), the positive electrode is manufactured (step S2), and the negative electrode is manufactured (step S3) can be changed as appropriate.
  • the electrode body 30 is produced using the positive electrode 31 and the negative electrode 32 (step S4). More specifically, the separator 33 is disposed between the positive electrode 31 and the negative electrode 32, and the laminate of the positive electrode 31, the separator 33, and the negative electrode 32 is wound in a spiral shape. Thereby, the electrode body 30 which has a winding structure is produced.
  • the side surface of the electrode body 30 produced in this way is pressed to make the electrode body 30 flat, and then the electrode body 30 is inserted into the outer can 10 (step S5).
  • the insulator 15 is disposed on the bottom surface in the outer can 10
  • one end of the electrode body 30 in the direction perpendicular to the winding direction is disposed on the insulator 15.
  • the lid plate 20 described above is prepared, and as shown in FIG. 2, the tip of the positive electrode lead 34 is connected to the lid plate 20, and the tip of the negative electrode lead 35 is connected to the negative electrode terminal 22 provided on the lid plate 20.
  • the cover plate 20 is disposed inside the opening of the outer can 10, and the inner wall surface of the outer can 10 and the outer peripheral edge of the cover plate 20 are joined.
  • the electrolytic solution is adjusted by the above-described method, and the electrolytic solution is injected from the inlet 24 of the lid plate 20 attached to the outer can 10 (step S6).
  • step S7 the sealed battery 1 is manufactured.
  • a porous insulating layer 31c may be formed on at least one surface 311 of the produced positive electrode 31 by the method described above (step S8). Further, the porous insulating layer 32c may be formed on at least one surface 321 of the manufactured negative electrode 32 by the method described above.
  • the porous insulating layers 31 c and 32 c may be formed on at least one of the positive electrode 31 and the negative electrode 32.
  • the porous insulating layer 31c may be formed after the positive electrode 31 is manufactured (step S2) and before the electrode body 30 is manufactured (step S4). (Step S8).
  • the production of the positive electrode 31 (step S1) and the formation of the porous insulating layer 31c (step S8) can also be performed before the preparation of the outer can (step S1).
  • the porous insulating layer 32c may be formed after the negative electrode 32 is manufactured (step S3) and before the electrode body 30 is manufactured (step S4). (Step S8).
  • the production of the negative electrode 32 (step S3) and the formation of the porous insulating layer 31c (step S8) can also be performed before the preparation of the outer can (step S1) and the production of the positive electrode 31 (step S1).
  • Example 1 ⁇ Preparation of positive electrode> Li 1.02 Ni 0.5 Co 0.2 Mn 0.3 O 2 as positive electrode active material : (50 parts by mass) and LiCoO 2 (50 parts by mass), and 10 % of polyvinylidene fluoride (PVdF) as a binder N-methyl-2-pyrrolidone (NMP) solution containing 20% by mass: 20 parts by mass of artificial graphite as a conductive additive: 1 part by mass and ketjen black: 1 part by mass using a biaxial kneader And kneaded. Thereafter, NMP was added to the kneaded mixture to adjust the viscosity, thereby preparing a positive electrode mixture-containing paste.
  • PVdF polyvinylidene fluoride
  • NMP N-methyl-2-pyrrolidone
  • This positive electrode mixture-containing paste was intermittently applied to both surfaces of an aluminum foil (positive electrode current collector) having a thickness of 15 ⁇ m while adjusting the thickness, and dried. Thereafter, calendar treatment was performed to adjust the thickness of the positive electrode mixture layer so that the total thickness was 130 ⁇ m, and the positive electrode was produced by cutting so that the width was 42 mm. And the lead part of the positive electrode was formed by welding the positive electrode tab to the exposed part of the aluminum foil of this positive electrode.
  • a negative electrode active material a composite in which the surface of SiO is coated with a carbon material (the amount of the carbon material in the composite is 20 mass%, the average particle size is 5 ⁇ m, hereinafter referred to as “SiO / carbon material composite”) and the average Graphite having a particle size of 16 ⁇ m mixed with SiO / carbon material composite in an amount of 5.0% by mass: 97.5% by mass, SBR: 1.5% by mass, and carboxymethyl cellulose (thickening Agent): 1% by mass was mixed with water to prepare a slurry for forming a negative electrode mixture layer.
  • SiO / carbon material composite the average particle size of 16 ⁇ m mixed with SiO / carbon material composite in an amount of 5.0% by mass: 97.5% by mass
  • SBR 1.5% by mass
  • carboxymethyl cellulose (thickening Agent) 1% by mass was mixed with water to prepare a slurry for forming a negative electrode mixture layer.
  • This slurry for forming a negative electrode mixture layer was applied to both sides of a copper foil (thickness: 8 ⁇ m) as a current collector, and vacuum dried at 120 ° C. for 12 hours. And the thickness of the negative mix layer was adjusted so that the total thickness might be 110 micrometers by performing a press process. Then, the negative electrode was produced by cut
  • ⁇ Preparation of outer can> An aluminum outer can having the appearance shown in FIG. 1 and having a horizontal dimension of 51 mm, a vertical dimension of 48 mm, a plate thickness of 0.3 mm, and an apparent thickness of 5.05 mm was produced. At that time, a square recess 41 was formed at the square end of the outer can. In addition, the recessed part made the length of the surface direction of a side wall part 0.5 mm, the depth of the recessed part 0.2 mm, and the length of one side of the recessed part 9 mm.
  • a sealed battery as shown in FIG. 1 was produced by welding the peripheral edge of the opening of the outer can in which the wound electrode body and the electrolytic solution were stored, and the outer peripheral edge of the lid.
  • the weakened part was formed by partially reducing the welding strength. Specifically, the laser beam irradiation intensity was adjusted at the time of welding so that the penetration depth of the weakened portion was 0.1 mm, and the penetration depth of the other welded portions was 0.18 mm.
  • Example 2 A sealed battery was fabricated in the same manner as in Example 1 except that an electrolytic solution to which triethylphosphonoacetate was added instead of 2-propynyl 2- (diethoxyphosphoryl) acetate was used.
  • Example 3 A sealed battery was produced in the same manner as in Example 1 except that an electrolytic solution to which allyl diethylphosphonoacetate was added instead of 2-propynyl 2- (diethoxyphosphoryl) acetate was used.
  • Example 4 Point was 3.0 wt% the amount of SiO / carbon material composite from 5.0 wt%, Li 1.02 Ni 0.5 Co 0.2 Mn 0.3 O 2 30 parts by weight from 50 parts by weight (LiCoO 2 was 70 parts by mass) and all the steps were performed except that the amount of 2-propynyl 2- (diethoxyphosphoryl) acetate added to the electrolyte was changed from 1.5% by weight to 1.0% by weight.
  • a sealed battery was produced in the same manner as in Example 1.
  • Point was 8.0 wt% the amount of SiO / carbon material composite from 5.0 wt%, Li 1.02 Ni 0.5 Co 0.2 Mn 0.3 O 2 60 parts by mass from 50 parts by weight (LiCoO 2 was 40 parts by mass) and all the steps were performed except that the amount of 2-propynyl 2- (diethoxyphosphoryl) acetate added to the electrolyte was changed from 1.5% by weight to 2.0% by weight.
  • a sealed battery was produced in the same manner as in Example 1.
  • Point was 10.0 wt% the amount of SiO / carbon material composite from 5.0 wt%, Li 1.02 Ni 0.5 Co 0.2 Mn 0.3 O 2 to 70 parts by mass 50 parts by weight Except for the point that LiCoO 2 was 30 parts by mass and the amount of 2-propynyl 2- (diethoxyphosphoryl) acetate added to the electrolyte was 1.5% to 3.0% by mass
  • a sealed battery was produced in the same manner as in Example 1.
  • Example 7 Concave portions were formed in two upper portions of the square of the aluminum outer can having a horizontal dimension of 51 mm, a vertical dimension of 48 mm, a plate thickness of 0.3 mm, and an apparent thickness of 5.05 mm.
  • the specifications of the recesses were the same as in Example 1. Further, the amount of 2-propynyl 2- (diethoxyphosphoryl) acetate added to the electrolytic solution was adjusted from 1.5% by weight to 2.0% by weight. Except for the above changes, a sealed battery was produced in the same manner as in Example 1.
  • Example 8 Concave portions were formed at two locations in the center of the aluminum outer can having a horizontal dimension of 51 mm, a vertical dimension of 48 mm, a plate thickness of 0.3 mm, and an apparent thickness of 5.05 mm.
  • the length of the surface direction of the side wall part was 0.5 mm
  • the depth of the recessed part was 0.2 mm
  • the horizontal dimension of the recessed part was 7 mm
  • the vertical dimension of the recessed part was 35 mm.
  • a sealed battery was produced in the same manner as in Example 1 except that the above outer can was used.
  • Example 9 A sealed battery was fabricated in the same manner as in Example 1 except that a cleaving vent was provided on the lid plate 20 and no fragile portion was formed at the welded portion between the lid plate 20 and the outer can 10.
  • Example 10 A solution of N-methyl-2-pyrrolidone (NMP) containing 5% by mass of polyvinylidene fluoride (PVdF) as a binder: 100 parts by mass and boehmite powder (average particle size 1 ⁇ m): 100 parts by mass were mixed.
  • a porous insulating layer forming slurry was prepared. This porous insulating layer-forming slurry was applied to both sides of the calendered positive electrode (total thickness 130 ⁇ m) used in Example 1 (the coating thickness was 3 ⁇ m on both sides) and dried to form both sides of the positive electrode. A porous insulating layer was formed. Furthermore, the positive electrode was produced by cut
  • NMP N-methyl-2-pyrrolidon
  • Example 2 A sealed battery was produced in the same manner as Example 1 except that the outer can was not provided with a recess.
  • Example 3 A sealed battery was fabricated in the same manner as in Example 1 except that an electrolytic solution to which 2-propynyl 2- (diethoxyphosphoryl) acetate was not added was used.
  • Example 4 A sealed battery was fabricated in the same manner as in Example 1 except that an electrolytic solution added with 1,3-propane sultone was used instead of 2-propynyl 2- (diethoxyphosphoryl) acetate.
  • the sealed battery was charged under the same conditions as the above-described measurement of the battery capacity. After charging of the sealed battery was measured thickness T 1 of the outer can. Thereafter, the sealed battery was stored in a thermostat set at 85 ° C. for 24 hours, then taken out of the thermostat and allowed to stand at room temperature for 3 hours, and then the thickness T 2 of the outer can was measured again.
  • the thickness of the outer can in the present test means the thickness between the flat portions (wide side surfaces) of the outer can.
  • the thickness of the outer can was measured using a caliper (for example, Mitutoyo Corp .; CD-15CX) at the center of the flat surface in units of 1/100 mm.
  • the battery swelling (%) was obtained by the following formula.
  • the negative electrode has a material containing Si and O as constituent elements, and a phosphonoacetate compound such as 2-propynyl 2- (diethoxyphosphoryl) acetate or triethylphosphonoacetate is added as an electrolyte.
  • the electrolyte solution used is used. Accordingly, in a sealed battery having a lithium-containing composite oxide containing nickel as a transition metal as a positive electrode active material, gas generation in the battery case 2 can be suppressed when the internal pressure of the battery case 2 increases. .
  • the battery case 2 is recessed toward the inside of the battery case 2 on the straight line L extending from the corner part of the flat part 13 to the central part at the corner part of the flat part 13.
  • a recess 41 is provided.
  • the concave portion 41 is formed in the flat portion 13 so that the corner portion 41c is located on the straight line L and on the corner portion side of the flat portion 13 in the concave portion 41, so that the deformation of the flat portion 13 is initially performed. Can be suppressed in stages. Therefore, the deformation of the battery case 2 can be further reliably suppressed.
  • the deformation of the plane portion 13 can be further reliably suppressed. Thereby, the deformation
  • the battery case 2 of the sealed battery 1 has a columnar shape having a bottom surface in which the rectangular short side is formed in an arc shape.
  • the shape of the battery case may be other shapes such as a hexahedron.
  • the battery case 2 has a pair of opposed flat portions 13 (side surfaces), and the concave portions 41 are formed in the flat portions 13, but the present invention is not particularly limited thereto.
  • the battery case does not have a pair of opposing side surfaces, such as when the battery case is formed in a triangular cylinder shape, it is only necessary that a recess be formed somewhere on the side surface of the battery case.
  • the flat surface portion 13 (side surface) of the battery case 2 has a rectangular shape, but the side surface of the battery case may have a polygonal shape other than the rectangular shape, a circular shape, an elliptical shape, or the like. Moreover, after forming the side surface of the battery case into a polygonal shape (including a rectangular shape), the side surface of the battery case can be formed into various shapes such as chamfering a part of the corners of the side surface.
  • the present invention can be used for a sealed battery including a battery case in which an electrode body and an electrolytic solution are stored.

Abstract

Obtained is a structure for a sealed cell capable of suppressing deformation of the cell case even when internal pressure increases inside the cell case, while suppressing the generation of gas inside the cell case. The sealed cell (1) is provided with an electrode body (30) enclosed inside the cell case (2) and an electrolytic solution. A positive electrode (31) uses, as a positive-electrode active substance, lithium and a lithium-containing composite oxide including a transition metal. At least a portion of the lithium-containing composite oxide includes nickel as the transition metal. A negative electrode (32) includes a graphitic carbon material and a material including Si and O as constituent elements (the atomic ratio (x) of O to Si being 0.5 ≤ × ≤ 1.5). The electrolytic solution contains a phosphonoacetate compound. A concave section (41) that is recessed toward the inside of the cell case (2) is formed on the side surface of the cell case (2).

Description

密閉型電池及びその製造方法Sealed battery and method for manufacturing the same
　本発明は、電池ケース内に電解液及び電極体が封入された密閉型電池、及びその製造方法に関する。 The present invention relates to a sealed battery in which an electrolytic solution and an electrode body are enclosed in a battery case, and a manufacturing method thereof.
　電池ケース内に電解液及び電極体が封入された密閉型電池として、例えば、特開２００６－２０２６４７号公報、特開２００４－０４７４０４号公報、及び特開２００５－２５９６９７号公報に示すようなリチウムイオン二次電池が知られている。リチウムイオン二次電池に用いられる高容量な電極活物質として、正極活物質はニッケルを含んだリチウム含有複合酸化物が、負極活物質はシリコン酸化物などのリチウムと合金化が可能な材料が、それぞれ知られている。これらの材料からなる活物質を組み合わせることにより、高容量なリチウムイオン二次電池が得られる。 As a sealed battery in which an electrolytic solution and an electrode body are enclosed in a battery case, for example, lithium ions as disclosed in JP 2006-202647 A, JP 2004-047404 A, and JP 2005-259697 A Secondary batteries are known. As a high-capacity electrode active material used for lithium ion secondary batteries, the positive electrode active material is a lithium-containing composite oxide containing nickel, and the negative electrode active material is a material that can be alloyed with lithium such as silicon oxide. Each is known. A high-capacity lithium ion secondary battery can be obtained by combining active materials made of these materials.
　ところで、ニッケルを含んだリチウム含有複合酸化物は、合成由来の不純物である炭酸リチウム、炭酸水素リチウム及び水酸化リチウムなどが分解される際に炭酸ガス等を発生する。また、シリコン酸化物は、充放電時の化学反応に伴う体積変化が大きい。そのため、電池の充放電サイクル毎にシリコン酸化物内の粒子が粉砕される。そうすると、表面に析出したシリコンが非水電解液の溶媒と反応して電池内でガスが発生する。 By the way, the lithium-containing composite oxide containing nickel generates carbon dioxide gas or the like when the synthesis-derived impurities such as lithium carbonate, lithium hydrogen carbonate, and lithium hydroxide are decomposed. Silicon oxide has a large volume change due to a chemical reaction during charge and discharge. Therefore, the particles in the silicon oxide are pulverized for each charge / discharge cycle of the battery. As a result, the silicon deposited on the surface reacts with the solvent of the non-aqueous electrolyte, and gas is generated in the battery.
　このように、電池ケース内で充放電時に活物質からガスが発生すると、該電池ケース内の圧力が上昇し、該電池ケースに変形を生じさせる可能性がある。特に、近年、携帯電話などでは高容量で且つ厚みの小さい幅広の電池が多く用いられている。そのため、電池ケース内の圧力変化が生じやすいとともに、電池ケース内の圧力変化によって該電池ケースが変形を生じやすくなっている。 As described above, when gas is generated from the active material during charging / discharging in the battery case, the pressure in the battery case increases, which may cause deformation of the battery case. In particular, in recent years, wide capacity batteries with a high capacity and a small thickness are often used in mobile phones and the like. Therefore, the pressure change in the battery case is likely to occur, and the battery case is likely to be deformed by the pressure change in the battery case.
　そのため、本発明では、電池ケース内でのガス発生を抑制しつつ、電池ケースの内圧が上昇した場合でも該電池ケースの変形を抑制可能な密閉型電池の構成を得ることを目的とする。 Therefore, an object of the present invention is to obtain a configuration of a sealed battery that can suppress deformation of the battery case even when the internal pressure of the battery case increases while suppressing gas generation in the battery case.
　本発明の一実施形態に係る密閉型電池は、正極及び負極を有する電極体と、電解液と、内部に前記電極体及び前記電解液が封入される電池ケースとを備える。前記正極は、正極活物質として、リチウム及び遷移金属を含むリチウム含有複合酸化物が用いられる。前記リチウム含有複合酸化物の少なくとも一部は、遷移金属としてニッケルを含む。前記負極は、負極活物質として、Ｓｉ及びＯを構成元素に含む材料（ただし、Ｓｉに対するＯの原子比ｘは、０．５≦ｘ≦１．５）と黒鉛質炭素材料とを含む。前記電解液は、ホスホノアセテート類化合物を含有する。前記電池ケースの側面には、該電池ケースの内方に向かって凹んだ凹部が形成されている（第１の構成）。 A sealed battery according to an embodiment of the present invention includes an electrode body having a positive electrode and a negative electrode, an electrolytic solution, and a battery case in which the electrode body and the electrolytic solution are enclosed. In the positive electrode, a lithium-containing composite oxide containing lithium and a transition metal is used as a positive electrode active material. At least a part of the lithium-containing composite oxide contains nickel as a transition metal. The negative electrode includes, as a negative electrode active material, a material containing Si and O as constituent elements (however, an atomic ratio x of O to Si is 0.5 ≦ x ≦ 1.5) and a graphitic carbon material. The electrolytic solution contains a phosphonoacetate compound. On the side surface of the battery case, a concave portion that is recessed toward the inside of the battery case is formed (first configuration).
　電解液内にホスホノアセテート類化合物を含むことにより、該ホスホノアセテート類化合物によって、Ｓｉ及びＯを構成元素として含有した材料を含む負極活物質と電解液との反応を制御してガスの発生を抑制することができる。 By including a phosphonoacetate compound in the electrolyte, the phosphonoacetate compound controls the reaction between the negative electrode active material containing a material containing Si and O as a constituent element and the electrolyte, and generates gas. Can be suppressed.
　しかも、上述の構成では、電池ケースの側面に、該電池ケースに内方に向かって凹んだ凹部を設けることにより、電池ケース内の圧力が上昇した場合でも該電池ケースの変形を抑制することができる。 In addition, in the above-described configuration, the battery case can be prevented from being deformed even when the pressure in the battery case rises by providing the battery case with a concave portion recessed inwardly on the side surface of the battery case. it can.
　したがって、電解液内のホスホノアセテート類化合物及び電池ケースの側面の凹部によって、電池ケースの変形を効果的に抑制することができる。 Therefore, deformation of the battery case can be effectively suppressed by the phosphonoacetate compound in the electrolytic solution and the concave portion on the side surface of the battery case.
　前記第１の構成において、前記ホスホノアセテート類化合物は、下記一般式（１）のＲ３に３重結合を有する化合物であるのが好ましい（第２の構成）。 In the first configuration, the phosphonoacetate compound is preferably a compound having a triple bond in R 3 of the following general formula (1) (second configuration).
Figure JPOXMLDOC01-appb-C000003
Figure JPOXMLDOC01-appb-C000003
　上記一般式（１）中、Ｒ１～Ｒ３は、それぞれ独立して、ハロゲン原子で置換されていてもよい、炭素数１～１２のアルキル基、アルケニル基またはアルキニル基を示す。ｎは、０～６の整数を示す。 In the general formula (1), R 1 to R 3 each independently represents an alkyl group, alkenyl group or alkynyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom. n represents an integer of 0 to 6.
　このように、ホスホノアセテート類化合物において、Ｒ３に３重結合を有する構成の場合、Ｓｉ及びＯを構成元素として含有した材料を含む負極活物質と電解液との反応をより確実に抑制することができる。したがって、電池ケース内のガス発生による該電池ケースの変形をより確実に抑制することができる。 Thus, in the case of the phosphonoacetate compound having a triple bond at R 3 , the reaction between the negative electrode active material containing a material containing Si and O as a constituent element and the electrolytic solution is more reliably suppressed. be able to. Therefore, deformation of the battery case due to gas generation in the battery case can be more reliably suppressed.
　前記第２の構成において、前記ホスホノアセテート類化合物は、前記一般式（１）のＲ３がプロピニル基である化合物であるのが好ましい（第３の構成）。 In the second configuration, the phosphonoacetate compound is preferably a compound in which R 3 in the general formula (1) is a propynyl group (third configuration).
　これにより、Ｓｉ及びＯを構成元素として含有した材料を含む負極活物質と電解液との反応をさらに確実に抑制することができる。したがって、電池ケース内のガス発生による該電池ケースの変形をさらに確実に抑制することができる。 Thereby, the reaction between the negative electrode active material containing a material containing Si and O as constituent elements and the electrolytic solution can be more reliably suppressed. Therefore, deformation of the battery case due to gas generation in the battery case can be further reliably suppressed.
　前記第３の構成において、前記ホスホノアセテート類化合物は、２－プロピニル２－（ジエトキシホスホリル）アセテートであるのが好ましい（第４の構成）。 In the third configuration, the phosphonoacetate compound is preferably 2-propynyl 2- (diethoxyphosphoryl) acetate (fourth configuration).
　前記第１から第４の構成のうちいずれか一つの構成において、前記正極及び前記負極の少なくとも一方は、主面上及び／または前記主面の対向面上に多孔性絶縁層が形成されていることが好ましい（第５の構成）。 In any one of the first to fourth configurations, at least one of the positive electrode and the negative electrode has a porous insulating layer formed on a main surface and / or on a surface opposite to the main surface. It is preferable (fifth configuration).
　電極体に設けられた多孔性絶縁層は、主として、繰り返しの充放電サイクルにおける容量劣化を低減する機能を有する。前記第１から第４の構成のうちいずれか一つの構成を有する密閉型電池では、上述したように、ガスの発生及び電池ケースの変形が抑制されるため、電池ケースによる電極体の押さえつけがゆるむのを抑制することができる。この結果、電極体から多孔性絶縁層が脱落しにくくなり、多孔性絶縁層の上記機能が損なわれるのを防止することができる。 The porous insulating layer provided on the electrode body mainly has a function of reducing capacity deterioration in repeated charge / discharge cycles. In the sealed battery having any one of the first to fourth configurations, the generation of gas and the deformation of the battery case are suppressed as described above, so that the pressing of the electrode body by the battery case is loosened. Can be suppressed. As a result, it becomes difficult for the porous insulating layer to fall off from the electrode body, and the above-described function of the porous insulating layer can be prevented from being impaired.
　前記第１から第５の構成のうちいずれか一つの構成において、前記電池ケースの側面は、少なくとも一つの角部分を有し、前記凹部は、前記電池ケースの側面の角部分から前記電池ケースの側面の中央部分へと延びる直線上に配置されていることが好ましい（第６の構成）。 In any one of the first to fifth configurations, the side surface of the battery case has at least one corner portion, and the concave portion extends from the corner portion of the side surface of the battery case. It is preferable to arrange on a straight line extending to the central portion of the side surface (sixth configuration).
　このように電池ケースの側面の角部分から中央部分へと延びる直線上に凹部を設けることにより、電池ケースの側面の剛性を部分的に高めることができ、該電池ケースの側面の変形を抑制することができる。しかも、凹部は、変形を生じ易い側面中央部分ではなく、電池ケースの側面の角部分から中央部分へと延びる直線上に形成されるため、電池ケースが多少変形を生じても、凹部の形状を維持することができる。これにより、電池ケースの内圧が上昇した状態でも、該電池ケースの側面の変形を抑制することができる。 Thus, by providing the concave portion on the straight line extending from the corner portion to the center portion of the side surface of the battery case, the rigidity of the side surface of the battery case can be partially increased, and deformation of the side surface of the battery case is suppressed. be able to. In addition, since the recess is not formed on the center portion of the side surface where deformation is likely to occur, but is formed on a straight line extending from the corner portion of the side surface of the battery case to the center portion, the shape of the recess is formed even if the battery case is slightly deformed. Can be maintained. Thereby, even when the internal pressure of the battery case is increased, deformation of the side surface of the battery case can be suppressed.
　前記第６の構成において、前記電池ケースの側面は、矩形状に形成されており、前記凹部は、前記電池ケースの側面の四つの角部分のうち少なくとも一つに配置されていることが好ましい（第７の構成）。 In the sixth configuration, it is preferable that a side surface of the battery case is formed in a rectangular shape, and the concave portion is disposed in at least one of four corner portions of the side surface of the battery case ( (Seventh configuration).
　内圧の上昇によって電池ケースが膨らむ場合、電池ケースの矩形状の側面には、四つの角部分から中央部分へと延びる稜線が形成される。しかしながら、第７の構成のように、電池ケースの側面の四つの角部分のうち少なくとも一つに凹部を配置しておけば、稜線の形成が阻害され、結果として、電池ケースの側面の変形を抑制することができる。 When the battery case expands due to an increase in internal pressure, ridgelines extending from the four corners to the central part are formed on the rectangular side surface of the battery case. However, as in the seventh configuration, if the concave portion is disposed in at least one of the four corners of the side surface of the battery case, formation of the ridge line is hindered, resulting in deformation of the side surface of the battery case. Can be suppressed.
　前記第６または第７の構成において、前記電池ケースは、少なくとも一対の対向する側面を有し、前記凹部は、前記電池ケースの一対の側面それぞれに形成されているのが好ましい（第８の構成）。 In the sixth or seventh configuration, it is preferable that the battery case has at least a pair of opposing side surfaces, and the recess is formed on each of the pair of side surfaces of the battery case (eighth configuration). ).
　一対の対向する側面それぞれに凹部を形成することによって、一対の側面それぞれの変形を抑制することができ、結果として、電池ケース全体の変形をより確実に抑制することができる。 By forming a recess on each of the pair of opposing side surfaces, the deformation of each of the pair of side surfaces can be suppressed, and as a result, the deformation of the entire battery case can be more reliably suppressed.
　前記第６から第８の構成のうちいずれか一つの構成において、前記凹部は、前記電池ケースの側面の法線方向から見て、多角形状に形成されているのが好ましい（第９の構成）。 In any one of the sixth to eighth configurations, the recess is preferably formed in a polygonal shape when viewed from the normal direction of the side surface of the battery case (9th configuration). .
　この構成では、凹部は複数の凹部側面を有するため、該複数の凹部側面によって、電池ケースの側面の変形を複数の方向で抑制することができる。しかも、凹部は複数の角部を有するため、該角部によっても電池ケースの側面の剛性を複数の方向で高めることができる。これにより、該電池ケースの側面の変形をより確実に抑制することができる。 In this configuration, since the recess has a plurality of recess side surfaces, deformation of the side surface of the battery case can be suppressed in a plurality of directions by the plurality of recess side surfaces. Moreover, since the recess has a plurality of corner portions, the rigidity of the side surface of the battery case can be increased in a plurality of directions also by the corner portions. Thereby, the deformation | transformation of the side surface of this battery case can be suppressed more reliably.
　前記第９の構成において、前記凹部の角部分は、前記電池ケースの側面の角部分から前記電池ケースの側面の中央部分へと延びる直線上に位置していることが好ましい（第１０の構成）。 In the ninth configuration, the corner portion of the recess is preferably located on a straight line extending from the corner portion of the side surface of the battery case to the central portion of the side surface of the battery case (tenth configuration). .
　これにより、多角形状の凹部の角部分によって、電池ケースが変形するのを抑制できる。すなわち、凹部では、該凹部の角部分で最も剛性が高くなる。そのため、電池ケースの側面において、変形を生じ易い中央部分ではなく、角部分から中央部分へと延びる直線上に凹部の角部分を配置することで、凹部の形状をより確実に維持することができ、結果として、電池ケースの側面の変形をより確実に抑制することができる。 Thereby, the battery case can be prevented from being deformed by the corners of the polygonal recesses. That is, in the concave portion, the rigidity is highest at the corner portion of the concave portion. Therefore, on the side surface of the battery case, the shape of the concave portion can be more reliably maintained by arranging the corner portion of the concave portion on a straight line extending from the corner portion to the central portion instead of the central portion that easily deforms. As a result, deformation of the side surface of the battery case can be more reliably suppressed.
　本発明の一実施形態に係る密閉型電池の製造方法は、側面に凹部を有する、有底筒状の外装缶を準備するステップと、リチウム含有複合酸化物を含有する正極活物質層を正極集電体上に形成し、正極を作製するステップと、Ｓｉ及びＯを構成元素に含む材料（ただし、Ｓｉに対するＯの原子比ｘは、０．５≦ｘ≦１．５）と黒鉛質炭素材料とを含有する負極活物質層を負極集電体上に形成し、負極を作製するステップと、前記正極及び前記負極を有する電極体を作製するステップと、前記電極体を前記外装缶内に挿入するステップと、ホスホノアセテート類化合物を含有する電解液を前記外装缶内に注入するステップと、前記電極体及び前記電解液を収納した外装缶を密閉するステップと、を備える。前記リチウム含有複合酸化物は、遷移金属としてニッケルを含む（第１の方法）。 A manufacturing method of a sealed battery according to an embodiment of the present invention includes a step of preparing a bottomed cylindrical outer can having a recess on a side surface, and a positive electrode active material layer containing a lithium-containing composite oxide. A step of forming a positive electrode on a conductor, and a material containing Si and O as constituent elements (however, an atomic ratio x of O to Si is 0.5 ≦ x ≦ 1.5) and a graphitic carbon material And forming a negative electrode active material layer on the negative electrode current collector, producing a negative electrode, producing an electrode body having the positive electrode and the negative electrode, and inserting the electrode body into the outer can A step of injecting an electrolytic solution containing a phosphonoacetate compound into the outer can, and a step of sealing the outer can containing the electrode body and the electrolytic solution. The lithium-containing composite oxide contains nickel as a transition metal (first method).
　前記第１の方法では、ホスホノアセテート類化合物を含有する電解液を外装缶に注入する。このため、第１の方法によって製造された密閉型電池の外装缶内では、ホスホノアセテート類化合物によって、Ｓｉ及びＯを構成元素として含有した材料を含む負極活物質と電解液との反応が制御され、ガスの発生が抑制される。 In the first method, an electrolytic solution containing a phosphonoacetate compound is injected into an outer can. For this reason, in the outer can of the sealed battery manufactured by the first method, the reaction between the negative electrode active material containing a material containing Si and O as a constituent element and the electrolytic solution is controlled by the phosphonoacetate compound. Gas generation is suppressed.
　しかも、第１の方法によって製造された密閉型電池では、外装缶の側面の凹部によって外装缶の変形が抑制される。 Moreover, in the sealed battery manufactured by the first method, the deformation of the outer can is suppressed by the concave portion on the side surface of the outer can.
　したがって、第１の方法によれば、外装缶が変形しにくい密閉型電池を製造することができる。 Therefore, according to the first method, a sealed battery in which the outer can is difficult to deform can be manufactured.
　前記第１の方法において、前記ホスホノアセテート類化合物は、上記一般式（１）のＲ３に３重結合を有する化合物であることが好ましい（第２の方法）。 In the first method, the phosphonoacetate compound is preferably a compound having a triple bond in R 3 of the general formula (1) (second method).
　前記第２の方法において、前記ホスホノアセテート類化合物は、前記一般式（１）のＲ３がプロピニル基である化合物であることが好ましい（第３の方法）。 In the second method, the phosphonoacetate compound is preferably a compound in which R 3 in the general formula (1) is a propynyl group (third method).
　前記第３の方法において、前記ホスホノアセテート類化合物は、２－プロピニル２－（ジエトキシホスホリル）アセテートであることが好ましい（第４の方法）。 In the third method, the phosphonoacetate compound is preferably 2-propynyl 2- (diethoxyphosphoryl) acetate (fourth method).
　前記第１から第４の方法のうちいずれか一つの方法は、前記正極及び前記負極の少なくとも一方の主面上及び／または前記主面の対向面上に、多孔性絶縁層を形成するステップ、をさらに備えていてもよい（第５の方法）。 Any one of the first to fourth methods includes a step of forming a porous insulating layer on at least one main surface of the positive electrode and the negative electrode and / or on the opposite surface of the main surface; May be further provided (fifth method).
図１は、本発明の実施形態に係る密閉型電池の概略構成を示す斜視図である。FIG. 1 is a perspective view showing a schematic configuration of a sealed battery according to an embodiment of the present invention. 図２は、図１におけるＩＩ－ＩＩ線断面図である。2 is a cross-sectional view taken along line II-II in FIG. 図３は、密閉型電池の概略構成を示す側面図である。FIG. 3 is a side view showing a schematic configuration of the sealed battery. 図４は、図３における電池ケースのＩＶ－ＩＶ線断面図である。4 is a cross-sectional view of the battery case taken along line IV-IV in FIG. 図５は、他の形状の凹部の一例を示す図１相当図である。FIG. 5 is a view corresponding to FIG. 1 and showing an example of a recess having another shape. 図６は、密閉型電池において脆弱部が開裂した後の様子を示す図１相当図である。FIG. 6 is a view corresponding to FIG. 1 showing a state after the fragile portion is cleaved in the sealed battery. 図７Ａは、密閉型電池における正極の垂直断面の一部を示す図である。FIG. 7A is a diagram illustrating a part of a vertical cross section of a positive electrode in a sealed battery. 図７Ｂは、図７Ａとは別の正極の垂直断面の一部を示す図である。FIG. 7B is a diagram showing a part of a vertical cross section of a positive electrode different from FIG. 7A. 図８Ａは、密閉型電池における負極の垂直断面の一部を示す図である。FIG. 8A is a diagram showing a part of a vertical cross section of a negative electrode in a sealed battery. 図８Ｂは、図８Ａとは別の負極の垂直断面の一部を示す図である。FIG. 8B is a diagram showing a part of a vertical cross section of a negative electrode different from FIG. 8A. 図９は、本発明の実施形態に係る密閉型電池の製造方法を示すフローチャートである。FIG. 9 is a flowchart showing a method for manufacturing a sealed battery according to an embodiment of the present invention. 図１０は、本発明の実施形態に係る密閉型電池の別の製造方法を示すフローチャートである。FIG. 10 is a flowchart showing another method for manufacturing a sealed battery according to an embodiment of the present invention.
　以下、図面を参照し、本発明の実施の形態を詳しく説明する。図中の同一または相当部分については同一の符号を付してその説明は繰り返さない。 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are denoted by the same reference numerals and description thereof will not be repeated.
　（全体構成）
　図１は、本発明の実施形態に係る密閉型電池１の概略構成を示す斜視図である。この密閉型電池１は、有底筒状の外装缶１０と、該外装缶１０の開口を覆う蓋板２０と、該外装缶１０内に収納される電極体３０とを備える。外装缶１０に蓋板２０を取り付けることによって、内部に空間を有する柱状の電池ケース２が構成される。なお、この電池ケース２内には、電極体３０以外に、非水電解液（以下、単に電解液ともいう）も封入されている。 (overall structure)
FIG. 1 is a perspective view showing a schematic configuration of a sealed battery 1 according to an embodiment of the present invention. The sealed battery 1 includes a bottomed cylindrical outer can 10, a cover plate 20 that covers an opening of the outer can 10, and an electrode body 30 that is accommodated in the outer can 10. By attaching the cover plate 20 to the outer can 10, the columnar battery case 2 having a space inside is formed. In addition to the electrode body 30, a non-aqueous electrolyte (hereinafter also simply referred to as an electrolyte) is enclosed in the battery case 2.
　外装缶１０は、アルミニウム合金製の有底筒状部材であり、蓋板２０とともに電池ケース２を構成する。外装缶１０は、図１に示すように、長方形の短辺側が円弧状に形成された底面１１を有する有底筒状の部材である。詳しくは、外装缶１０は、底面１１と、滑らかな曲面を有する扁平筒状の側壁１２とを備える。側壁１２は、対向して配置される矩形状（本実施形態では長方形状）の一対の平面部１３と、該一対の平面部１３同士を接続する半円筒状の半円筒部１４とを有する。すなわち、外装缶１０は、底面１１の短辺方向に対応する厚み方向の寸法が、底面１１の長辺方向に対応する幅方向よりも小さくなるように、扁平形状に形成されている。また、この外装缶１０は、後述するように正極リード３４に接続される蓋板２０と接合されているため、密閉型電池１の正極端子も兼ねている。 The outer can 10 is a bottomed cylindrical member made of an aluminum alloy, and constitutes the battery case 2 together with the cover plate 20. As shown in FIG. 1, the outer can 10 is a bottomed cylindrical member having a bottom surface 11 in which a rectangular short side is formed in an arc shape. Specifically, the outer can 10 includes a bottom surface 11 and a flat cylindrical side wall 12 having a smooth curved surface. The side wall 12 has a pair of rectangular portions (rectangular shapes in the present embodiment) disposed opposite to each other, and a semicylindrical semicylindrical portion 14 that connects the pair of planar portions 13 to each other. That is, the outer can 10 is formed in a flat shape such that the dimension in the thickness direction corresponding to the short side direction of the bottom surface 11 is smaller than the width direction corresponding to the long side direction of the bottom surface 11. Further, since the outer can 10 is joined to the lid plate 20 connected to the positive electrode lead 34 as will be described later, it also serves as the positive electrode terminal of the sealed battery 1.
　図２に示すように、外装缶１０の内側の底部には、後述する電極体３０の正極３１と負極３２との間で外装缶１０を介して短絡が発生するのを防止するためのポリエチレンシートからなる絶縁体１５が配置されている。電極体３０は、該絶縁体１５上に一方の端部が位置付けられるように配置されている。 As shown in FIG. 2, a polyethylene sheet for preventing a short circuit from occurring between the positive electrode 31 and the negative electrode 32 of the electrode body 30, which will be described later, via the outer can 10 at the bottom of the inner side of the outer can 10. An insulator 15 made of is arranged. The electrode body 30 is disposed on the insulator 15 so that one end thereof is positioned.
　蓋板２０は、外装缶１０に電極体３０が挿入された後、外装缶１０の開口部を覆うように、該外装缶１０の開口部に溶接によって接合される。この蓋板２０は、外装缶１０と同様、アルミニウム合金製の部材からなり、該外装缶１０の開口部の内側に嵌合可能なように長方形の短辺側が円弧状に形成されている。また、蓋板２０には、その長手方向の中央部分に貫通孔が形成されている。この貫通孔内には、ポリプロピレン製の絶縁パッキング２１及びステンレス鋼製の負極端子２２が挿通されている。具体的には、概略柱状の負極端子２２が挿通された概略円筒状の絶縁パッキング２１が前記貫通孔の周縁部に嵌合されている。 After the electrode body 30 is inserted into the outer can 10, the cover plate 20 is joined to the opening of the outer can 10 by welding so as to cover the opening of the outer can 10. The cover plate 20 is made of an aluminum alloy member, like the outer can 10, and has a rectangular short side formed in an arc shape so as to fit inside the opening of the outer can 10. Moreover, the through-hole is formed in the center part of the longitudinal direction in the cover board 20. As shown in FIG. An insulating packing 21 made of polypropylene and a negative electrode terminal 22 made of stainless steel are inserted into the through hole. Specifically, a substantially cylindrical insulating packing 21 into which a substantially columnar negative electrode terminal 22 is inserted is fitted to the peripheral portion of the through hole.
　負極端子２２は、円柱状の軸部の両端に平面部がそれぞれ一体形成された構成を有する。負極端子２２は、平面部が外部に露出する一方、該軸部が絶縁パッキング２１内に位置付けられるように、該絶縁パッキング２１に対して配置されている。この負極端子２２には、ステンレス鋼製のリード板２７が接続されている。これにより、負極端子２２は、リード板２７及び負極リード３５を介して、電極体３０の負極３２に電気的に接続されている。なお、リード板２７と絶縁パッキング２１との間には、絶縁体２６が配置されている。 The negative electrode terminal 22 has a configuration in which flat portions are integrally formed at both ends of a cylindrical shaft portion. The negative electrode terminal 22 is disposed with respect to the insulating packing 21 so that the flat surface portion is exposed to the outside and the shaft portion is positioned in the insulating packing 21. A stainless steel lead plate 27 is connected to the negative terminal 22. Thereby, the negative electrode terminal 22 is electrically connected to the negative electrode 32 of the electrode body 30 via the lead plate 27 and the negative electrode lead 35. An insulator 26 is disposed between the lead plate 27 and the insulating packing 21.
　蓋板２０には、負極端子２２と並んで電解液の注入口２４が形成されている。注入口２４は、平面視で略円形状に形成されている。また、注入口２４は、蓋板２０の厚み方向に径が２段階で変化するように小径部及び大径部を有している。この注入口２４から電解液が注入された後、注入口２４は、該注入口２４の径の変化に対応して段状に形成された封止栓２５によって封止される。そして、封止栓２５と注入口２４の周縁部との間に隙間が生じないように、該封止栓２５の大径部側の平面外周部と注入口２４の周縁部とはレーザー溶接によって接合される。これにより、電極体３０及び電解液を収納した外装缶１０が密閉される。 The lid plate 20 is formed with an electrolyte inlet 24 along with the negative electrode terminal 22. The injection port 24 is formed in a substantially circular shape in plan view. The injection port 24 has a small diameter portion and a large diameter portion so that the diameter changes in two steps in the thickness direction of the lid plate 20. After the electrolytic solution is injected from the injection port 24, the injection port 24 is sealed by a sealing plug 25 formed in a step shape corresponding to a change in the diameter of the injection port 24. The flat outer peripheral portion of the sealing plug 25 and the peripheral portion of the injection port 24 are laser-welded so that no gap is generated between the sealing plug 25 and the peripheral portion of the injection port 24. Be joined. Thereby, the outer can 10 containing the electrode body 30 and the electrolytic solution is sealed.
　電極体３０は、それぞれシート状に形成された正極３１及び負極３２を、例えば両者の間及び該負極３２の下側にセパレータ３３がそれぞれ位置するように重ね合わせた状態で、図２に示すように渦巻状に巻回することによって形成された巻回電極体である。電極体３０は、正極３１、負極３２及びセパレータ３３を重ね合わせた状態で巻回した後、押しつぶして扁平状に形成される。 As shown in FIG. 2, the electrode body 30 has a positive electrode 31 and a negative electrode 32 formed in a sheet shape, for example, in a state where the separators 33 are positioned between them and below the negative electrode 32, respectively. It is the winding electrode body formed by winding in a spiral shape. The electrode body 30 is formed in a flat shape after being wound in a state where the positive electrode 31, the negative electrode 32, and the separator 33 are overlapped with each other.
　ここで、図２では、電極体３０の外周側の数層分しか図示していない。しかしながら、この図２では電極体３０の内周側部分の図示を省略しているだけであり、当然のことながら、電極体３０の内周側にも正極３１、負極３２及びセパレータ３３が存在する。また、図２では、蓋板２０の電池内方に配置される絶縁体等の記載も省略している。 Here, in FIG. 2, only a few layers on the outer peripheral side of the electrode body 30 are shown. However, in FIG. 2, the illustration of the inner peripheral side portion of the electrode body 30 is omitted, and naturally, the positive electrode 31, the negative electrode 32, and the separator 33 are also present on the inner peripheral side of the electrode body 30. . Further, in FIG. 2, description of an insulator and the like disposed inside the battery of the cover plate 20 is also omitted.
　（正極）
　正極３１は、正極活物質を含有する正極活物質層を、アルミニウム等の金属箔製の正極集電体の両面にそれぞれ設けたものである。詳しくは、正極３１は、リチウムイオンを吸蔵・放出可能なリチウム含有酸化物である正極活物質、導電助剤、及びバインダなどを含む正極合剤を、アルミニウム箔などからなる正極集電体上に塗布して乾燥させることによって形成される。ただし、例えば転写等、塗布以外の方法で正極活物質層を正極集電体上に形成してもよい。なお、導電助剤及びバインダとしては、公知の材料を使用することができる。例えば、導電助剤としては、カーボンブラック等の炭素材料を挙げることができ、バインダとしては、ポリフッ化ビニリデン（ＰＶｄＦ）等の有機溶剤系バインダを挙げることができる。 (Positive electrode)
The positive electrode 31 is obtained by providing positive electrode active material layers containing a positive electrode active material on both surfaces of a positive electrode current collector made of a metal foil such as aluminum. Specifically, the positive electrode 31 has a positive electrode active material that is a lithium-containing oxide capable of inserting and extracting lithium ions, a conductive additive, a positive electrode mixture including a binder, and the like on a positive electrode current collector made of an aluminum foil or the like. It is formed by applying and drying. However, the positive electrode active material layer may be formed on the positive electrode current collector by a method other than coating, such as transfer. In addition, a well-known material can be used as a conductive support agent and a binder. For example, the conductive auxiliary can include a carbon material such as carbon black, and the binder can include an organic solvent binder such as polyvinylidene fluoride (PVdF).
　正極活物質としては、リチウム及び遷移金属を含むリチウム含有複合酸化物を用いる。正極活物質として、複数の種類のリチウム含有複合酸化物を用いてもよい。リチウム含有複合酸化物は、例えば、ＬｉＣｏＯ２などのリチウムコバルト酸化物やＬｉＭｎ２Ｏ４などのリチウムマンガン酸化物、ＬｉＮｉＯ２などのリチウムニッケル酸化物等である。また、前記リチウム含有複合酸化物の少なくとも一部は、遷移金属としてニッケルを含む。 As the positive electrode active material, a lithium-containing composite oxide containing lithium and a transition metal is used. A plurality of types of lithium-containing composite oxides may be used as the positive electrode active material. Examples of the lithium-containing composite oxide include lithium cobalt oxides such as LiCoO 2 , lithium manganese oxides such as LiMn 2 O 4 , lithium nickel oxides such as LiNiO 2, and the like. Moreover, at least a part of the lithium-containing composite oxide contains nickel as a transition metal.
　遷移金属としてニッケルを含むリチウム含有複合酸化物は、複合酸化物を構成する遷移金属元素として少なくともニッケルを含有するものであり、コバルト、マンガン、チタン、クロム、鉄、銅、銀、タンタル、ニオブ、ジルコニウムなどの他の遷移金属を構成元素として含有していてもよい。また、遷移金属としてニッケルを含むリチウム含有複合酸化物は、例えば、ホウ素、リン、亜鉛、アルミニウム、カルシウム、ストロンチウム、バリウム、ゲルマニウム、スズ、マグネシウムなどの遷移金属元素以外の元素を含んでいてもよい。
The lithium-containing composite oxide containing nickel as a transition metal contains at least nickel as a transition metal element constituting the composite oxide, and includes cobalt, manganese, titanium, chromium, iron, copper, silver, tantalum, niobium, Other transition metals such as zirconium may be contained as a constituent element. The lithium-containing composite oxide containing nickel as a transition metal may contain elements other than transition metal elements such as boron, phosphorus, zinc, aluminum, calcium, strontium, barium, germanium, tin, and magnesium. .
　リチウム含有複合酸化物は、Ｌｉ含有化合物（水酸化リチウム・一水和物など）、Ｎｉ含有化合物（硫酸ニッケルなど）、Ｃｏ含有化合物（硫酸コバルトなど）、Ｍｎ含有化合物（硫酸マンガンなど）などを混合し、焼成するなどして製造することができる。 Lithium-containing composite oxides include Li-containing compounds (such as lithium hydroxide monohydrate), Ni-containing compounds (such as nickel sulfate), Co-containing compounds (such as cobalt sulfate), and Mn-containing compounds (such as manganese sulfate). It can be manufactured by mixing and baking.
　焼成条件は、例えば、８００～１０５０℃で１～２４時間とすることができるが、一旦焼成温度よりも低い温度（例えば、２５０～８５０℃）まで加熱し、その温度で保持することにより予備加熱を行い、その後に焼成温度まで昇温して反応を進行させることが好ましい。予備加熱の時間については特に制限はないが、通常、０．５～３０時間程度とすればよい。また、焼成時の雰囲気は、酸素を含む雰囲気（すなわち、大気中）、不活性ガス（アルゴン、ヘリウム、窒素など）と酸素ガスとの混合雰囲気、酸素ガス雰囲気などとすることができるが、その際の酸素濃度（体積基準）は、１５％以上であることが好ましく、１８％以上であることが好ましい。　 The firing conditions can be, for example, 800 to 1050 ° C. for 1 to 24 hours, but once heated to a temperature lower than the firing temperature (for example, 250 to 850 ° C.) and maintained at that temperature, preheating is performed. After that, it is preferable to raise the temperature to the firing temperature to advance the reaction. There is no particular limitation on the preheating time, but it is usually about 0.5 to 30 hours. The atmosphere during firing can be an atmosphere containing oxygen (that is, in the air), a mixed atmosphere of an inert gas (such as argon, helium, or nitrogen) and oxygen gas, or an oxygen gas atmosphere. The oxygen concentration (volume basis) is preferably 15% or more, and more preferably 18% or more. *
　（負極）
　負極３２は、負極活物質を含有する負極活物質層を、銅等の金属箔製の負極集電体の両面にそれぞれ設けたものである。詳しくは、負極３２は、リチウムイオンを吸蔵・放出可能な負極活物質、導電助剤、及びバインダなどを含む負極合剤を、銅箔などからなる負極集電体上に塗布して乾燥させることによって形成される。ただし、例えば転写等、塗布以外の方法で負極活物質層を負極集電体上に形成してもよい。なお、導電助剤及びバインダとしては、公知の材料を使用することができる。例えば、導電助剤としては、黒鉛、及びソフトカーボンやハードカーボン等の炭素材料を挙げることができ、バインダとしては、スチレンブタジエンゴム（ＳＢＲ）等の水分散系バインダや、カルボキシメチルセルロース等の増粘剤を挙げることができる。負極活物質は、Ｓｉ及びＯを構成元素に含む材料（ただし、Ｓｉに対するＯの原子比ｘは、０．５≦ｘ≦１．５である。以下、当該材料を「ＳｉＯｘ」ともいう。）及び黒鉛質炭素材料を含む。 (Negative electrode)
In the negative electrode 32, negative electrode active material layers containing a negative electrode active material are provided on both sides of a negative electrode current collector made of a metal foil such as copper. Specifically, the negative electrode 32 is formed by applying and drying a negative electrode mixture containing a negative electrode active material capable of occluding and releasing lithium ions, a conductive additive, a binder, and the like on a negative electrode current collector made of copper foil or the like. Formed by. However, the negative electrode active material layer may be formed on the negative electrode current collector by a method other than coating, such as transfer. In addition, a well-known material can be used as a conductive support agent and a binder. For example, examples of the conductive assistant include graphite and carbon materials such as soft carbon and hard carbon. Examples of the binder include an aqueous dispersion binder such as styrene butadiene rubber (SBR), and a thickening agent such as carboxymethyl cellulose. An agent can be mentioned. The negative electrode active material is a material containing Si and O as constituent elements (provided that the atomic ratio x of O to Si is 0.5 ≦ x ≦ 1.5. Hereinafter, this material is also referred to as “SiO x ”. ) And graphitic carbon materials.
　ＳｉＯｘは、Ｓｉの微結晶または非晶質相を含んでいてもよい。この場合、ＳｉとＯの原子比は、Ｓｉに微結晶のＳｉ及び非晶質相のＳｉを含めた比率となる。すなわち、ＳｉＯｘには、非晶質のＳｉＯ２マトリックス中に、Ｓｉ（例えば、微結晶Ｓｉ）が分散した構造のものが含まれる。よって、非晶質のＳｉＯ２とその中に分散しているＳｉとを合わせて、上述の原子比ｘが０．５≦ｘ≦１．５を満足していればよい。例えば、非晶質のＳｉＯ２マトリックス中にＳｉが分散した構造を有する材料において、ＳｉＯ２とＳｉのモル比が１：１の場合には、ｘ＝１なので、構造式はＳｉＯと表記される。このような構造の材料の場合、例えば、Ｘ線回折分析では、Ｓｉ（微結晶Ｓｉ）に起因するピークが観察されない場合もあるが、透過型電子顕微鏡で観察すると、微細な微結晶Ｓｉの存在を確認できる。 SiO x may contain a microcrystalline or amorphous phase of Si. In this case, the atomic ratio between Si and O is a ratio in which Si includes microcrystalline Si and amorphous phase Si. That is, SiO x includes a structure in which Si (for example, microcrystalline Si) is dispersed in an amorphous SiO 2 matrix. Therefore, it is sufficient that the above-mentioned atomic ratio x satisfies 0.5 ≦ x ≦ 1.5 by combining amorphous SiO 2 and Si dispersed therein. For example, in a material having a structure in which Si is dispersed in an amorphous SiO 2 matrix, when the molar ratio of SiO 2 to Si is 1: 1, since x = 1, the structural formula is expressed as SiO. . In the case of a material having such a structure, for example, in X-ray diffraction analysis, a peak due to Si (microcrystalline Si) may not be observed, but when observed with a transmission electron microscope, the presence of fine microcrystalline Si is present. Can be confirmed.
　ＳｉＯｘと炭素材料とは、複合化されて、複合体を構成する。例えば、ＳｉＯｘの表面は、炭素材料によって被覆されていることが望ましい。一般的に、ＳｉＯｘは導電性が乏しい。そのため、ＳｉＯｘを負極活物質として用いる際には、良好な電池特性を確保するという観点から、導電性材料（導電助剤）を用いて負極内におけるＳｉＯｘと導電性材料との混合及び分散を良好な状態にして、優れた導電ネットワークを形成する必要がある。上述のようにＳｉＯｘと炭素材料とを複合化して複合体を構成することにより、例えば、単にＳｉＯｘと炭素材料などの導電性材料とを混合した材料を用いる場合よりも、負極に良好な導電ネットワークが形成される。 SiO x and the carbon material are combined to form a composite. For example, the surface of SiO x is desirably covered with a carbon material. In general, SiO x has poor conductivity. Therefore, when using SiO x as the negative electrode active material, mixing and dispersion of SiO x and the conductive material in the negative electrode using a conductive material (conductive aid) from the viewpoint of ensuring good battery characteristics. Must be in good condition to form an excellent conductive network. By configuring the complex composite of the SiO x and the carbon material as described above, for example, simply than when using a material obtained by mixing the conductive material such as SiO x and the carbon material, good negative electrode A conductive network is formed.
　負極にＳｉＯｘと炭素材料との複合体を使用する場合、炭素材料との複合化による効果を十分に得るために、ＳｉＯｘと炭素材料との比率は、１００質量部のＳｉＯｘに対して、炭素材料を５質量部以上とするのが好ましく、炭素材料を１０質量部以上とするのがより好ましい。また、前記複合体において、ＳｉＯｘと複合化する炭素材料の比率が高すぎると、負極合剤層中のＳｉＯｘの量が低下するため、電池の高容量化の効果が小さくなる虞がある。よって、１００質量部のＳｉＯｘに対して、炭素材料は５０質量部以下であることが好ましく、４０質量部以下であることがより好ましい。 When a composite of SiO x and a carbon material is used for the negative electrode, the ratio of SiO x to the carbon material is 100 parts by mass with respect to 100 parts by mass of SiO x in order to sufficiently obtain the effect of the composite with the carbon material. The carbon material is preferably 5 parts by mass or more, and more preferably 10 parts by mass or more. Further, in the composite, if the ratio of the carbon material to be composited with SiO x is too high, the amount of SiO x in the negative electrode mixture layer is reduced, so that the effect of increasing the capacity of the battery may be reduced. . Therefore, with respect to 100 parts by weight of SiO x, it is preferred that the carbon material is less than 50 parts by mass, more preferably not more than 40 parts by mass.
　ＳｉＯｘは、ＳｉとＳｉＯ２との混合物を加熱し、生成した酸化ケイ素のガスを冷却して析出させるなどの方法により、得られる。さらに、得られたＳｉＯｘを不活性ガス雰囲気下で熱処理することにより、粒子内部に微小なＳｉ相を形成させることができる。このときの熱処理温度および時間を調整することにより、形成されるＳｉ相の（１１１）回折ピークの半値幅を制御することができる。通常、熱処理温度は、およそ９００～１４００℃の範囲とし、熱処理時間は、およそ０．１～１０時間の範囲で設定すればよい。 SiO x is obtained by a method of heating a mixture of Si and SiO 2 and cooling and depositing the generated silicon oxide gas. Furthermore, by heat-treating the obtained SiO x under an inert gas atmosphere, a fine Si phase can be formed inside the particles. By adjusting the heat treatment temperature and time at this time, the half width of the (111) diffraction peak of the formed Si phase can be controlled. Usually, the heat treatment temperature is set in the range of about 900 to 1400 ° C., and the heat treatment time may be set in the range of about 0.1 to 10 hours.
　ＳｉＯｘとしては、上述したように、ＳｉＯｘの一次粒子の他、ＳｉＯｘ複合粒子や、ＳｉＯｘと炭素材料との造粒体が挙げられるが、以下、これらをまとめて「ＳｉＯｘ粒子」ともいう。 Examples of SiO x include, as described above, SiO x primary particles, SiO x composite particles, and granulated bodies of SiO x and a carbon material. Hereinafter, these are collectively referred to as “SiO x particles”. Also called.
　ＳｉＯｘ複合粒子は、例えば、ＳｉＯｘが分散媒に分散した分散液を用意し、それを噴霧し乾燥させることにより、得られる。分散媒としては、例えば、エタノール等を用いることができる。分散液の噴霧は、通常、５０～３００℃の雰囲気内で行うことが適当である。 The SiO x composite particles can be obtained, for example, by preparing a dispersion liquid in which SiO x is dispersed in a dispersion medium, and spraying and drying the dispersion liquid. For example, ethanol or the like can be used as the dispersion medium. It is appropriate to spray the dispersion liquid in an atmosphere of 50 to 300 ° C.
　ＳｉＯｘと炭素材料との造粒体は、振動型や遊星型のボールミルやロッドミル等を用いた機械的な方法を用いて、ＳｉＯｘを炭素材料とともに造粒させることにより得られる。 Zotsubutai the SiO x and the carbon material, with a mechanical method using a vibratory and planetary ball mill or a rod mill or the like, the SiO x can be obtained by granulating together with the carbon material.
　次に、上記ＳｉＯｘと炭素材料との複合体の作製方法について説明する。例えば、ＳｉＯｘ粒子（ＳｉＯｘ複合粒子、またはＳｉＯｘと炭素材料との造粒体）と炭化水素系ガスとを気相中にて加熱して、炭化水素系ガスの熱分解により生成した炭素を、ＳｉＯｘ粒子の表面上に堆積させることにより、ＳｉＯｘと炭素材料との複合体を作製する。このように、気相成長（ＣＶＤ）法によれば、炭化水素系ガスが複合粒子の隅々にまで行き渡り、粒子の表面や表面の空孔内に、導電性を有する炭素材料を含む薄くて均一な皮膜、つまり、炭素の被覆層を形成できることから、少量の炭素材料によってＳｉＯｘ粒子に均一に導電性を付与できる。 Next, a method for producing a composite of the SiO x and the carbon material will be described. For example, carbon produced by thermal decomposition of hydrocarbon gas by heating SiO x particles (SiO x composite particles or granulated body of SiO x and carbon material) and hydrocarbon gas in a gas phase. Is deposited on the surface of the SiO x particles to produce a composite of SiO x and a carbon material. As described above, according to the vapor deposition (CVD) method, the hydrocarbon-based gas spreads to every corner of the composite particle, and the surface of the particle and the pores in the surface are thin and contain a conductive carbon material. Since a uniform film, that is, a carbon coating layer can be formed, it is possible to uniformly impart conductivity to the SiO x particles with a small amount of carbon material.
　気相成長（ＣＶＤ）法の処理温度（雰囲気温度）については、炭化水素系ガスの種類によっても異なるが、通常、６００～１２００℃が適当であり、中でも、７００℃以上であることが好ましく、８００℃以上であることが更に好ましい。処理温度が高い方が不純物の残存が少なく、かつ導電性の高い炭素を含む被覆層を形成できるからである。 The processing temperature (atmospheric temperature) of the vapor deposition (CVD) method varies depending on the type of hydrocarbon gas, but is usually 600 to 1200 ° C., preferably 700 ° C. or higher. More preferably, it is 800 ° C. or higher. This is because the higher the treatment temperature, the less the remaining impurities, and the formation of a coating layer containing carbon having high conductivity.
　炭化水素系ガスの液体ソースとしては、トルエン、ベンゼン、キシレン、メシチレン等を用いることができるが、取り扱い易いトルエンが特に好ましい。これらを気化させる（例えば、窒素ガスでバブリングする）ことにより炭化水素系ガスを得ることができる。また、メタンガスやアセチレンガス等を用いることもできる。 As the liquid source of the hydrocarbon-based gas, toluene, benzene, xylene, mesitylene and the like can be used, but toluene that is easy to handle is particularly preferable. A hydrocarbon-based gas can be obtained by vaporizing them (for example, bubbling with nitrogen gas). Moreover, methane gas, acetylene gas, etc. can also be used.
　また、気相成長（ＣＶＤ）法にてＳｉＯｘ粒子（ＳｉＯｘ複合粒子、またはＳｉＯｘと炭素材料との造粒体）の表面を炭素材料で被覆した後に、石油系ピッチ、石炭系のピッチ、熱硬化性樹脂、及びナフタレンスルホン酸塩とアルデヒド類との縮合物よりなる群から選択される少なくとも１種の有機化合物を、炭素材料を含む被覆層に付着させた後、上記有機化合物が付着した粒子を焼成してもよい。 In addition, after coating the surface of SiO x particles (SiO x composite particles or a granulated body of SiO x and a carbon material) with a carbon material by a vapor deposition (CVD) method, a petroleum-based pitch or a coal-based pitch is used. At least one organic compound selected from the group consisting of a thermosetting resin and a condensate of naphthalene sulfonate and aldehydes is attached to a coating layer containing a carbon material, and then the organic compound is attached. The obtained particles may be fired.
　具体的には、表面が炭素材料で被覆されたＳｉＯｘ粒子（ＳｉＯｘ複合粒子、またはＳｉＯｘと炭素材料との造粒体）と、上記有機化合物とが分散媒に分散した分散液を用意し、この分散液を噴霧し乾燥して、有機化合物によって被覆された粒子を形成し、その有機化合物によって被覆された粒子を焼成する。 Specifically, a dispersion liquid is prepared in which SiO x particles (SiO x composite particles or a granulated body of SiO x and a carbon material) whose surface is coated with a carbon material and the organic compound are dispersed in a dispersion medium. The dispersion is sprayed and dried to form particles coated with the organic compound, and the particles coated with the organic compound are fired.
　上記ピッチとしては、等方性ピッチを用いることができる。また、上記熱硬化性樹脂としては、フェノール樹脂、フラン樹脂、フルフラール樹脂等を用いることができる。ナフタレンスルホン酸塩とアルデヒド類との縮合物としては、ナフタレンスルホン酸ホルムアルデヒド縮合物を用いることができる。 As the pitch, an isotropic pitch can be used. Moreover, as the thermosetting resin, phenol resin, furan resin, furfural resin, or the like can be used. As the condensate of naphthalene sulfonate and aldehydes, naphthalene sulfonic acid formaldehyde condensate can be used.
　表面が炭素材料で被覆されたＳｉＯｘ粒子（ＳｉＯｘ複合粒子、またはＳｉＯｘと炭素材料との造粒体）と上記有機化合物とを分散させるための分散媒としては、例えば、水、アルコール類（エタノール等）を用いることができる。分散液の噴霧は、通常、５０～３００℃の雰囲気内で行うことが適当である。焼成温度は、通常、６００～１２００℃が適当であるが、中でも７００℃以上が好ましく、８００℃以上であることが更に好ましい。処理温度が高い方が不純物の残存が少なく、かつ導電性の高い良質な炭素材料を含む被覆層を形成できるからである。ただし、処理温度はＳｉＯｘの融点以下であることを要する。 Examples of the dispersion medium for dispersing the organic compound with SiO x particles (SiO x composite particles or a granulated body of SiO x and a carbon material) whose surface is coated with a carbon material include, for example, water and alcohols (Ethanol etc.) can be used. It is appropriate to spray the dispersion liquid in an atmosphere of 50 to 300 ° C. The firing temperature is usually 600 to 1200 ° C., preferably 700 ° C. or higher, and more preferably 800 ° C. or higher. This is because the higher the processing temperature, the less the remaining impurities, and the formation of a coating layer containing a high-quality carbon material with high conductivity. However, the processing temperature needs to be lower than the melting point of SiO x .
　ＳｉＯｘ及び炭素材料の複合体とともに負極活物質として使用する黒鉛質炭素材料としては、例えば、鱗片状黒鉛などの天然黒鉛や、熱分解炭素類またはＭＣＭＢ、炭素繊維などの易黒鉛化炭素を２８００℃以上で黒鉛化処理した人造黒鉛などが挙げられる。 Examples of the graphitic carbon material used as the negative electrode active material together with the composite of SiO x and the carbon material include natural graphite such as flake graphite, pyrolytic carbons or graphitizable carbon such as MCMB and carbon fiber, 2800. Examples thereof include artificial graphite that has been graphitized at a temperature of at least ° C.
　なお、負極は、ＳｉＯｘを使用することによる高容量化の効果を得るために、ＳｉＯｘと炭素材料との複合体の負極活物質中の含有量が、０．０１質量％以上であることが好ましく、３質量％以上であることがより好ましい。また、充放電に伴うＳｉＯｘの体積変化による問題をより良好に回避する観点から、負極活物質中における前記複合体の含有量が、２０質量％以下であることが好ましく、１０質量％以下であることがより好ましい。 Note that the negative electrode in order to obtain the effect of the high capacity by using a SiO x, the content of the negative electrode active material in complex with SiO x and the carbon material is not less than 0.01 wt% Is preferable, and it is more preferable that it is 3 mass% or more. Further, from the viewpoint of better avoiding the problem due to the volume change of SiO x accompanying charge / discharge, the content of the composite in the negative electrode active material is preferably 20% by mass or less, and preferably 10% by mass or less. More preferably.
　Ｓｉ及びＯを構成元素に含む材料（ただし、Ｓｉに対するＯの原子比ｘは、０．５≦ｘ≦１．５である。以下、当該材料を「ＳｉＯｘ」ともいう。）及び黒鉛質炭素材料を含む。 Material containing Si and O as constituent elements (however, the atomic ratio x of O to Si is 0.5 ≦ x ≦ 1.5. Hereinafter, the material is also referred to as “SiO x ”) and graphitic carbon Contains materials.
　図２に示すように、電極体３０の正極３１には、正極リード３４が接続されている一方、負極３２には負極リード３５が接続されている。これにより、正極リード３４及び負極リード３５が、電極体３０の外部に引き出されている。そして、この正極リード３４の先端側は、蓋板２０に接続されている。一方、負極リード３５の先端側は、後述するように、リード板２７を介して負極端子２２に接続されている。 As shown in FIG. 2, a positive electrode lead 34 is connected to the positive electrode 31 of the electrode body 30, while a negative electrode lead 35 is connected to the negative electrode 32. As a result, the positive electrode lead 34 and the negative electrode lead 35 are drawn out of the electrode body 30. The tip end side of the positive electrode lead 34 is connected to the lid plate 20. On the other hand, the distal end side of the negative electrode lead 35 is connected to the negative electrode terminal 22 via a lead plate 27 as described later.
　（セパレータ）
　セパレータ３３は、例えばポリエチレンやポリプロピレンなどから構成されるポリオレフィン製の多孔質膜である。このポリオレフィン製の多孔質膜は、一般的に、リチウム二次電池に使用される。 (Separator)
The separator 33 is a polyolefin porous film made of, for example, polyethylene or polypropylene. This polyolefin porous film is generally used for lithium secondary batteries.
　なお、ポリエチレンの融点は、略１３０℃である。そのため、セパレータとしてポリエチレン製の多孔質膜を用いた場合、電池内部の温度が１３０℃を超えると、セパレータが溶けて収縮し、正極及び負極で短絡を生じる可能性がある。よって、高温環境下での安全性を高めるために、例えば耐熱性樹脂や耐熱性無機フィラーを積層したセパレータを用いるのが好ましい。 The melting point of polyethylene is approximately 130 ° C. Therefore, when a polyethylene porous membrane is used as the separator, if the temperature inside the battery exceeds 130 ° C., the separator may melt and contract, and a short circuit may occur between the positive electrode and the negative electrode. Therefore, in order to improve safety in a high temperature environment, it is preferable to use a separator in which, for example, a heat resistant resin or a heat resistant inorganic filler is laminated.
　特に、熱可塑性樹脂を主体とする多孔質層（I）と、耐熱温度が１５０℃以上のフィラーを主体として含む多孔質層（II）とを有する積層型のセパレータを使用するのが好ましい。このようなセパレータは、高いシャットダウン特性と耐熱収縮性とを兼ね備えているからである。
In particular, it is preferable to use a laminated separator having a porous layer (I) mainly composed of a thermoplastic resin and a porous layer (II) mainly composed of a filler having a heat resistant temperature of 150 ° C. or higher. This is because such a separator has high shutdown characteristics and heat shrinkage resistance.
　（電解液）
　電解液は、リチウム塩及び下記の一般式（１）を満足するホスホノアセテート類化合物を有機溶媒に溶解させることによって調製される。すなわち、電解液は、下記の一般式（１）を満足するホスホノアセテート類化合物を含有する。 (Electrolyte)
The electrolytic solution is prepared by dissolving a lithium salt and a phosphonoacetate compound satisfying the following general formula (1) in an organic solvent. That is, the electrolytic solution contains a phosphonoacetate compound that satisfies the following general formula (1).
Figure JPOXMLDOC01-appb-C000004
Figure JPOXMLDOC01-appb-C000004
　上記一般式（１）中、Ｒ１～Ｒ３は、それぞれ独立して、ハロゲン原子で置換されてもよい、炭素数１～１２のアルキル基、アルケニル基またはアルキニル基を示す。ｎは、０～６の整数を示す。 In the general formula (1), R 1 to R 3 each independently represents an alkyl group, alkenyl group or alkynyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom. n represents an integer of 0 to 6.
　上記一般式（１）で表されるホスホノアセテート類化合物の中でも、トリエチルホスホノアセテート、アリルジエチルホスホノアセテート、２－プロピニルジメチルホスホノアセテート、２－プロピニル２－（ジエトキシホスホリル）アセテートなどが好ましい。 Among the phosphonoacetate compounds represented by the general formula (1), triethylphosphonoacetate, allyldiethylphosphonoacetate, 2-propynyldimethylphosphonoacetate, 2-propynyl-2- (diethoxyphosphoryl) acetate and the like preferable.
　特に、上記一般式（１）において、Ｒ３に三重結合を有する物質が好ましい。すなわち、Ｒ３がプロピニル基またはニトリル基であるのが好ましい。Ｒ３がプロピニル基の一例として、Ｒ１、Ｒ２がエトキシ基であり、ｎ＝１である、２－プロピニル２－（ジエトキシホスホリル）アセテートが挙げられる。 In particular, in the general formula (1), a substance having a triple bond at R 3 is preferable. That is, R 3 is preferably a propynyl group or a nitrile group. An example of a propynyl group in which R 3 is propynyl includes 2-propynyl 2- (diethoxyphosphoryl) acetate, in which R 1 and R 2 are ethoxy groups and n = 1.
　通常、電池に使用する電解液には、例えば、ビニレンカーボネート（ＶＣ）、フルオロエチレンカーボネート（ＦＥＣ）、無水酸、スルホン酸エステル、ジニトリル、１，３－プロパンスルトン、ジフェニルジスルフィド、シクロヘキシルベンゼン、ビフェニル、フルオロベンゼン、ｔ－ブチルベンゼン、スクシノニトリルなどの添加剤（これらの誘導体も含む）が適宜加えられる。添加剤は、例えばサイクル特性、高温膨れ抑制や過充電防止などの安全性向上など、要求される特性に応じて選択される。 Usually, the electrolyte used in the battery includes, for example, vinylene carbonate (VC), fluoroethylene carbonate (FEC), acid anhydride, sulfonate ester, dinitrile, 1,3-propane sultone, diphenyl disulfide, cyclohexylbenzene, biphenyl, Additives (including these derivatives) such as fluorobenzene, t-butylbenzene, succinonitrile and the like are appropriately added. The additive is selected in accordance with required characteristics such as cycle characteristics, safety improvement such as suppression of high-temperature blistering and prevention of overcharge.
　ところで、ニッケルが含有されたリチウム複合酸化物を正極活物質として用いると、ＬｉＣｏＯ２のみを正極活物質として用いる場合よりも、高温環境下での電池の膨れが大きくなる。これは、ニッケルが高温環境下では不安定であるため、高充電状態にあるニッケルと溶媒または添加剤との反応性が高く、ニッケルが活性点となりやすいことが原因と考えられる。そのため、ニッケルの活性点と溶媒または添加剤との余剰反応による過剰なガスの発生に起因する電池の膨れや、反応生成物がニッケル界面に堆積することにより生じる電池内の抵抗の上昇、そして高温貯蔵後の容量回復率の大幅な低下が問題となっていた。よって、従来は、これらの対策の一つとして、１，３－プロパンスルトン、スクシノニトリルなどの添加剤が電解液に添加されていた。これにより、上記余剰反応が抑制される。 By the way, when a lithium composite oxide containing nickel is used as a positive electrode active material, the swelling of the battery in a high temperature environment becomes larger than when only LiCoO 2 is used as the positive electrode active material. This is presumably because nickel is unstable in a high temperature environment, so that the reactivity between nickel in a highly charged state and a solvent or additive is high, and nickel tends to be an active site. For this reason, battery swelling due to excessive gas generation due to excess reaction between nickel active sites and solvent or additive, increase in resistance in the battery caused by reaction products depositing on the nickel interface, and high temperature A significant decrease in the capacity recovery rate after storage has been a problem. Therefore, conventionally, as one of these measures, additives such as 1,3-propane sultone and succinonitrile have been added to the electrolytic solution. Thereby, the said excess reaction is suppressed.
　上述のような従来の添加剤では、高温貯蔵性が改善され、電池の膨れが抑えられるものの、電池の充放電サイクルの特性が悪化してしまうことが多かった。これは、添加量が少ない場合でも、１，３－プロパンスルトン、スクシノニトリルなどの従来の添加剤が、正極活物質の活性点以外とも反応して反応生成物が堆積し、その結果、容量低下及び抵抗の増大を招くからであると考えられる。 Although the conventional additives as described above improve the high-temperature storage property and suppress the swelling of the battery, the characteristics of the battery charge / discharge cycle are often deteriorated. This is because even when the addition amount is small, conventional additives such as 1,3-propane sultone and succinonitrile react with other than the active site of the positive electrode active material, and the reaction product is deposited. This is considered to result in a decrease and an increase in resistance.
　発明者らは、鋭意努力の結果、ニッケルが含有されているリチウム複合酸化物を正極活物質として使用するとともに、電解液にホスホノアセテート類化合物が含有されている場合に、充放電サイクルの特性を悪化させることなく、高温貯蔵性を改善し、電池の膨れを抑えられることを見出した。これは、ホスホノアセテート類化合物が、電解液と反応してガスを発生するニッケルの活性点を、被覆しているためと推測される。 As a result of diligent efforts, the inventors have used a lithium composite oxide containing nickel as a positive electrode active material, and when the electrolyte contains a phosphonoacetate compound, the characteristics of the charge / discharge cycle It has been found that the high temperature storage property can be improved and the swelling of the battery can be suppressed without deteriorating the battery. This is presumed to be because the phosphonoacetate compound covers the active sites of nickel that reacts with the electrolyte to generate gas.
　更に、負極にも、電池作製後の初回充放電時にホスホノアセテート類化合物によって被膜が形成されるが、ホスホノアセテート類化合物による被膜は、熱安定性が高く抵抗が小さい。よって、高温貯蔵下でも被膜が分解しにくく、抵抗の増加が抑制されていると考えられる。 Furthermore, a film is formed on the negative electrode by the phosphonoacetate compound at the first charge / discharge after the battery is produced, but the film by the phosphonoacetate compound has high thermal stability and low resistance. Therefore, it is considered that the coating is difficult to decompose even under high temperature storage, and the increase in resistance is suppressed.
　電解液は、これらのホスホノアセテート類化合物が、電池に使用する非水電解液（電池組み立ての際に使用する非水電解液。以下、同じ。）中に０．５質量％以上含まれていることが好ましく、より好ましくは１質量％以上である。非水電解液中にホスホノアセテート類化合物の量が少なすぎると、ガス発生を抑える効果を多少は得られるものの、ニッケルの活性点を十分に覆うことができず、電池の膨れを抑制する効果が低下する。一方、非水電解液中にホスホノアセテート類化合物が多すぎると、正極材の活性点以外でも反応を生じて、他の添加剤と同様、抵抗の増大を招く。そのため、ホスホノアセテート類化合物は、電池組み立ての際に使用する非水電解液中に、好ましくは５質量％以下、より好ましくは３質量％以下である。 The electrolyte contains 0.5% by mass or more of these phosphonoacetate compounds in a non-aqueous electrolyte used in a battery (non-aqueous electrolyte used in battery assembly, the same applies hereinafter). It is preferable that it is 1 mass% or more. If the amount of the phosphonoacetate compound in the non-aqueous electrolyte is too small, the effect of suppressing gas generation can be obtained to some extent, but the active point of nickel cannot be sufficiently covered, and the effect of suppressing battery swelling Decreases. On the other hand, if there are too many phosphonoacetate compounds in the nonaqueous electrolytic solution, a reaction occurs at a point other than the active site of the positive electrode material, which causes an increase in resistance like other additives. Therefore, the phosphonoacetate compound is preferably 5% by mass or less, more preferably 3% by mass or less, in the nonaqueous electrolytic solution used for battery assembly.
　従来の添加剤、例えば、既述のビニレンカーボネート、フルオロエチレンカーボネート、無水酸、スルホン酸エステル、ジニトリル、１，３－プロパンスルトン、ジフェニルジスルフィド、シクロヘキシルベンゼン、ビフェニル、フルオロベンゼン、ｔ－ブチルベンゼンなどの添加剤（これらの誘導体も含む）は、求める電池の特性に応じて、適宜併用しても構わない。 Conventional additives such as vinylene carbonate, fluoroethylene carbonate, anhydride, sulfonic acid ester, dinitrile, 1,3-propane sultone, diphenyl disulfide, cyclohexyl benzene, biphenyl, fluorobenzene, t-butyl benzene, etc. Additives (including these derivatives) may be used in combination as appropriate depending on the desired battery characteristics.
　特に、前記非水電解液は、ハロゲン置換された環状カーボネート（例えばフルオロエチレンカーボネート）とビニレンカーボネートとを含有した非水電解液を使用するのが好ましい。 In particular, as the non-aqueous electrolyte, it is preferable to use a non-aqueous electrolyte containing a halogen-substituted cyclic carbonate (for example, fluoroethylene carbonate) and vinylene carbonate.
　ハロゲン置換された環状カーボネートとしては、下記の一般式（２）で表される化合物を用いることができる。 As the halogen-substituted cyclic carbonate, a compound represented by the following general formula (2) can be used.
Figure JPOXMLDOC01-appb-C000005
Figure JPOXMLDOC01-appb-C000005
　前記一般式（２）中、Ｒ４、Ｒ５、Ｒ６及びＲ７は、水素、ハロゲン元素または炭素数１～１０のアルキル基を表しており、アルキル基の水素の一部または全部がハロゲン元素で置換されてもよい。Ｒ４、Ｒ５、Ｒ６及びＲ７のうち少なくとも１つはハロゲン元素である。Ｒ４、Ｒ５、Ｒ６及びＲ７は、それぞれが異なっていてもよく、２つ以上が同一であってもよい。Ｒ４、Ｒ５、Ｒ６及びＲ７がアルキル基である場合、その炭素数は少ないほど好ましい。前記ハロゲン元素としては、フッ素が特に好ましい。 In the general formula (2), R 4 , R 5 , R 6 and R 7 represent hydrogen, a halogen element or an alkyl group having 1 to 10 carbon atoms, and a part or all of hydrogen of the alkyl group is halogen. It may be substituted with an element. At least one of R 4 , R 5 , R 6 and R 7 is a halogen element. R 4 , R 5 , R 6 and R 7 may be different from each other, or two or more may be the same. When R 4 , R 5 , R 6 and R 7 are alkyl groups, the smaller the number of carbon atoms, the better. As the halogen element, fluorine is particularly preferable.
　このようなハロゲン元素で置換された環状カーボネートの中でも、４－フルオロ－１，３－ジオキソラン－２－オン（ＦＥＣ）が特に好ましい。 Among such cyclic carbonates substituted with a halogen element, 4-fluoro-1,3-dioxolan-2-one (FEC) is particularly preferable.
　電池に使用する非水電解液中では、ハロゲン置換された環状カーボネートの含有量は、１質量％以上が好ましく、ＶＣの含有量は、１質量％以上が好ましい。また、ハロゲン置換された環状カーボネートの含有量は、１．５質量％以上がより好ましく、ＶＣの含有量は、１．５質量％以上がより好ましい。 In the nonaqueous electrolytic solution used for the battery, the content of the halogen-substituted cyclic carbonate is preferably 1% by mass or more, and the content of VC is preferably 1% by mass or more. The halogen-substituted cyclic carbonate content is more preferably 1.5% by mass or more, and the VC content is more preferably 1.5% by mass or more.
　ただし、前記非水電解液中のハロゲン置換された環状カーボネートやＶＣの含有量が多すぎると、負極活物質にＳｉＯｘが含有されている場合、ＳｉＯｘの活性が低下したり、被膜形成の際に過剰なガスが発生して電池ケースの膨れの原因になったりする虞がある。よって、電池に使用する非水電解液において、ハロゲン置換された環状カーボネートの含有量は、１０質量％以下が好ましく、ＶＣの含有量は１０質量％以下が好ましい。また、ハロゲン置換された環状カーボネートの含有量は、５質量％以下がより好ましく、ＶＣの含有量は、５質量％以下がより好ましい。 However, when the content of halogen-substituted cyclic carbonate and VC of the non-aqueous electrolyte is too large, if the SiO x is contained in the anode active material, decreases the activity of SiO x or, in the film-forming At this time, excessive gas may be generated, which may cause the battery case to swell. Therefore, in the non-aqueous electrolyte used for the battery, the content of the halogen-substituted cyclic carbonate is preferably 10% by mass or less, and the content of VC is preferably 10% by mass or less. The halogen-substituted cyclic carbonate content is more preferably 5% by mass or less, and the VC content is more preferably 5% by mass or less.
　前記非水電解液に用いるリチウム塩としては、溶媒中で解離してリチウムイオンを形成するとともに、電池として使用される電圧範囲で分解などの副反応を起こしにくいものであれば、特に制限はない。例えば、リチウム塩として、ＬｉＣｌＯ４、ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＡｓＦ６、ＬｉＳｂＦ６などの無機リチウム塩、ＬｉＣＦ３ＳＯ３、ＬｉＣＦ３ＣＯ２、Ｌｉ２Ｃ２Ｆ４（ＳＯ３）２、ＬｉＮ（ＣＦ３ＳＯ２）２、ＬｉＣ（ＣＦ３ＳＯ２）３、ＬｉＣｎＦ２ｎ＋１ＳＯ３（ｎ≧２）、ＬｉＮ（ＲｆＯＳＯ２）２〔ここでＲｆはフルオロアルキル基〕などの有機リチウム塩などを用いることができる。 The lithium salt used in the non-aqueous electrolyte is not particularly limited as long as it dissociates in a solvent to form lithium ions and does not easily cause side reactions such as decomposition in a voltage range used as a battery. . For example, as a lithium salt, LiClO 4 , LiPF 6 , LiBF 4 , LiAsF 6 , LiSbF 6 and other inorganic lithium salts, LiCF 3 SO 3 , LiCF 3 CO 2 , Li 2 C 2 F 4 (SO 3 ) 2 , LiN ( Organic lithium salts such as CF 3 SO 2 ) 2 , LiC (CF 3 SO 2 ) 3 , LiC n F 2n + 1 SO 3 (n ≧ 2), LiN (RfOSO 2 ) 2 [where Rf is a fluoroalkyl group] Can be used.
　リチウム塩の前記非水電解液中の濃度としては、０．５～１．５ｍｏｌ／ｌが好ましく、０．９～１．２５ｍｏｌ／ｌがより好ましい。 The concentration of the lithium salt in the non-aqueous electrolyte is preferably 0.5 to 1.5 mol / l, more preferably 0.9 to 1.25 mol / l.
　前記非水電解液に用いる有機溶媒としては、前記リチウム塩を溶解できるとともに、電池として使用される電圧範囲で分解などの副反応を起こさないものであれば、特に限定されない。例えば、有機溶媒として、エチレンカーボネート、プロピレンカーボネート、ブチレンカーボネートなどの環状カーボネート；ジメチルカーボネート、ジエチルカーボネート、メチルエチルカーボネートなどの鎖状カーボネート；プロピオン酸メチルなどの鎖状エステル；γ－ブチロラクトンなどの環状エステル；ジメトキシエタン、ジエチルエーテル、１，３－ジオキソラン、ジグライム、トリグライム、テトラグライムなどの鎖状エーテル；ジオキサン、テトラヒドロフラン、２－メチルテトラヒドロフランなどの環状エーテル；アセトニトリル、プロピオニトリル、メトキシプロピオニトリルなどのニトリル類；エチレングリコールサルファイトなどの亜硫酸エステル類；などが挙げられる。これらの溶媒は、２種以上混合して用いることもできる。なお、より良好な特性の電池とするためには、エチレンカーボネートと鎖状カーボネートとの混合溶媒など、高い導電率が得られる溶媒の組み合わせにするのが望ましい。　 The organic solvent used in the non-aqueous electrolyte is not particularly limited as long as it can dissolve the lithium salt and does not cause a side reaction such as decomposition in a voltage range used as a battery. Examples of organic solvents include cyclic carbonates such as ethylene carbonate, propylene carbonate, and butylene carbonate; chain carbonates such as dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate; chain esters such as methyl propionate; cyclic esters such as γ-butyrolactone. Chain ethers such as dimethoxyethane, diethyl ether, 1,3-dioxolane, diglyme, triglyme and tetraglyme; cyclic ethers such as dioxane, tetrahydrofuran and 2-methyltetrahydrofuran; acetonitrile, propionitrile, methoxypropionitrile and the like; Nitriles; sulfites such as ethylene glycol sulfite; and the like. These solvents can be used in a mixture of two or more. In order to obtain a battery having better characteristics, it is desirable to use a combination of solvents such as a mixed solvent of ethylene carbonate and chain carbonate that can provide high conductivity. *
　（凹部）
　図１及び図３に示すように、外装缶１０の側壁１２の平面部１３には、複数の凹部４１が形成されている。凹部４１は、平面部１３に設けられていれば、大きさ、形状、個数などに制限はない。しかし、平面部１３の中央部に１個の凹部を設けるよりも、２個以上の凹部を設けた方が、電池ケースの変形をより抑制する効果が高いため好ましい。例えば、図１及び図３に示すように、外装缶１０の一対の平面部１３の四つの角部分に、凹部４１を形成する構成が考えられる。凹部４１は、平面部１３の四つの角部分すべてに形成されている必要はなく、平面部１３の四つの角部分のうち少なくとも１つに形成することもできる。以下、この図１及び図３の例について詳述する。 (Concave)
As shown in FIGS. 1 and 3, a plurality of recesses 41 are formed in the flat portion 13 of the side wall 12 of the outer can 10. If the recessed part 41 is provided in the plane part 13, there will be no restriction | limiting in a magnitude | size, a shape, a number. However, providing two or more recesses is preferable to providing one or more recesses in the center of the flat portion 13 because the effect of suppressing deformation of the battery case is higher. For example, as shown in FIG.1 and FIG.3, the structure which forms the recessed part 41 in the four corner | angular parts of a pair of plane part 13 of the armored can 10 can be considered. The concave portion 41 does not have to be formed in all four corner portions of the plane portion 13, and can be formed in at least one of the four corner portions of the plane portion 13. Hereinafter, the example of FIGS. 1 and 3 will be described in detail.
　凹部４１は、平面部１３の法線方向から見て、四角形状（本実施形態では正方形状）に形成されている。凹部４１は、矩形状の底面部４１ａと、該底面部４１ａの各辺に対応して電池ケース２の内方側に向かって延びる４つの側壁部４１ｂ（凹部側面）とを有する。また、凹部４１は、４つの側壁部４１ｂが外装缶１０の平面部１３の四辺に対して略平行になるように、該平面部１３に形成されている（図３参照）。 The recess 41 is formed in a quadrangular shape (in this embodiment, a square shape) when viewed from the normal direction of the flat surface portion 13. The recess 41 has a rectangular bottom surface portion 41a and four side wall portions 41b (recess side surfaces) extending toward the inner side of the battery case 2 corresponding to the respective sides of the bottom surface portion 41a. Moreover, the recessed part 41 is formed in this plane part 13 so that the four side wall parts 41b may become substantially parallel with respect to the four sides of the plane part 13 of the armored can 10 (refer FIG. 3).
　なお、凹部４１は、平面部１３の法線方向から見て、長方形や平行四辺形など、正方形以外の四角形状であってもよいし、三角形や五角形など他の多角形状であってもよい。また、凹部４１は、平面部１３の法線方向から見て、円形や楕円状であってもよい。 The recess 41 may have a quadrangular shape other than a square, such as a rectangle or a parallelogram, or another polygonal shape such as a triangle or a pentagon when viewed from the normal direction of the flat surface portion 13. Further, the concave portion 41 may be circular or elliptical when viewed from the normal direction of the plane portion 13.
　凹部４１は、図３に示すように、平面部１３の各角部分から中央部分へと延びる直線Ｌ上に配置されている。本実施形態では、平面部１３は矩形状であるため、直線Ｌは、平面部１３の対角線に沿って延びている。具体的には、凹部４１は、２つの側壁部４１ｂが接続される角部分４１ｃが、直線Ｌ上に位置するように、外装缶１０の平面部１３に設けられている。これにより、凹部４１において最も強度が高い角部分４１ｃが直線Ｌ上に位置するため、電池ケース２の変形を該角部分４１ｃによって阻害することができる。したがって、電池ケース２の変形を抑制することができる。しかも、直線Ｌ上に凹部４１の角部分４１ｃを設けることで、該角部分４１ｃを構成する２つの側壁部４１ｂによって、直線Ｌに対する２方向の変形を抑制することができる。これにより、電池ケース２において、直線Ｌ近辺での変形を抑制することができる。 The recessed part 41 is arrange | positioned on the straight line L extended from each corner | angular part of the plane part 13 to a center part, as shown in FIG. In the present embodiment, since the plane portion 13 is rectangular, the straight line L extends along the diagonal line of the plane portion 13. Specifically, the concave portion 41 is provided on the flat surface portion 13 of the outer can 10 so that a corner portion 41c to which the two side wall portions 41b are connected is positioned on the straight line L. Thereby, since the corner | angular part 41c with the highest intensity | strength in the recessed part 41 is located on the straight line L, a deformation | transformation of the battery case 2 can be inhibited by this corner | angular part 41c. Therefore, deformation of the battery case 2 can be suppressed. In addition, by providing the corner portion 41c of the concave portion 41 on the straight line L, deformation in two directions with respect to the straight line L can be suppressed by the two side wall portions 41b constituting the corner portion 41c. Thereby, in the battery case 2, the deformation | transformation in the straight line L vicinity can be suppressed.
　直線Ｌは、密閉型電池１の内部圧力の上昇に伴って電池ケース２が膨らんだ場合に外装缶１０に形成される稜線と一致する。電池ケース２の変形が進行すると、平面部１３の各角部分から延びる稜線同士が繋がる。しかしながら、本実施形態では、一対の平面部１３の各角部分に凹部４１が形成されているため、稜線上に凹部４１が位置することとなる。その結果、平面部１３の変形を、初期の段階で該凹部４１によって抑制することができる。 The straight line L coincides with the ridgeline formed on the outer can 10 when the battery case 2 swells as the internal pressure of the sealed battery 1 increases. When the deformation of the battery case 2 proceeds, ridge lines extending from each corner portion of the plane portion 13 are connected. However, in this embodiment, since the recessed part 41 is formed in each corner | angular part of a pair of plane part 13, the recessed part 41 will be located on a ridgeline. As a result, the deformation of the flat surface portion 13 can be suppressed by the concave portion 41 in the initial stage.
　また、凹部４１は、角部分４１ｃが直線Ｌにおける平面部１３の角部分側に位置するように、該直線Ｌ上に形成されている。これにより、平面部１３が変形を生じる初期の段階で、凹部４１によって、該平面部１３の変形をより確実に阻害することができる。したがって、電池ケース２の変形をより確実に抑制することができる。 Further, the concave portion 41 is formed on the straight line L so that the corner portion 41c is positioned on the corner portion side of the plane portion 13 in the straight line L. Thereby, at the initial stage in which the flat portion 13 is deformed, the concave portion 41 can more reliably inhibit the deformation of the flat portion 13. Therefore, deformation of the battery case 2 can be more reliably suppressed.
　なお、凹部４１は、側壁部４１ｂが直線Ｌ上に位置するように設けられていてもよい。この場合には、凹部４１の角部分４１ｃが直線Ｌ上に配置される場合のような作用効果は期待できないが、側壁部４１ｂによって電池ケース２の変形を抑制することができる。 In addition, the recessed part 41 may be provided so that the side wall part 41b may be located on the straight line L. FIG. In this case, the effect as in the case where the corner portion 41c of the concave portion 41 is arranged on the straight line L cannot be expected, but the deformation of the battery case 2 can be suppressed by the side wall portion 41b.
　凹部４１は、外装缶１０の一対の平面部１３において、互いに対向する位置に形成されている。すなわち、図３には一方の平面部１３のみを示しているが、他方の平面部１３にも該一方の平面部１３に形成された凹部４１と同じ位置に凹部４１が形成されている。これにより、電池ケース２における一対の平面部１３の変形を、凹部４１によって抑制できるため、電池ケース２の変形をより確実に抑制することができる。 The concave portions 41 are formed at positions facing each other in the pair of flat surface portions 13 of the outer can 10. That is, FIG. 3 shows only one flat portion 13, but the other flat portion 13 is also formed with a concave portion 41 at the same position as the concave portion 41 formed in the one flat portion 13. Thereby, since a deformation | transformation of a pair of plane part 13 in the battery case 2 can be suppressed by the recessed part 41, a deformation | transformation of the battery case 2 can be suppressed more reliably.
　凹部４１は、外装缶１０をプレス成形する際に、該外装缶１０とともにプレスによって形成される。したがって、凹部４１の側壁部４１ｂは、図４に断面で示すように、該凹部４１の底面部４１ａから開口側に向かって凹部４１が外方に拡がるように傾斜している。このプレス加工によって、凹部４１を構成する底面部４１ａ及び側壁部４１ｂの周辺部分で加工硬化が生じることから、該凹部４１の周辺部分の強度向上を図れる。したがって、電池ケース２の変形を、凹部４１によって、さらに確実に抑制することができる。 The concave portion 41 is formed by pressing together with the outer can 10 when the outer can 10 is press-molded. Therefore, as shown in a cross section in FIG. 4, the side wall 41 b of the recess 41 is inclined so that the recess 41 expands outward from the bottom surface 41 a of the recess 41 toward the opening side. By this press working, work hardening occurs in the peripheral portions of the bottom surface portion 41a and the side wall portion 41b constituting the concave portion 41, so that the strength of the peripheral portion of the concave portion 41 can be improved. Therefore, the deformation of the battery case 2 can be more reliably suppressed by the recess 41.
　凹部４１は、詳しくは後述するが、平面部１３において、端部のうちプレス成形が可能な最も端に形成されるのが好ましい。また、凹部４１は、側壁部４１ｂの傾斜が、プレス成形可能な角度の中で最も急勾配であるのが好ましい。さらに、凹部４１の深さは、電池ケース２内に収納される電極体３０等の機能を阻害しない範囲で、できるだけ深いのが好ましい。 Although the concave portion 41 will be described in detail later, it is preferable that the flat portion 13 is formed at the end that can be press-molded among the end portions. Moreover, it is preferable that the recessed part 41 has the steepest inclination of the side wall part 41b in the angle which can be press-molded. Furthermore, it is preferable that the depth of the recess 41 is as deep as possible within a range that does not hinder the functions of the electrode body 30 and the like housed in the battery case 2.
　以上、平面部１３の四つの角部分に凹部４１を設けた例を説明したが、本発明においては、例えば図５に示すように、平面部１３の中央部に複数の縦長形状の凹部６１を設けても構わない。図５では、２個の凹部６１を図示しているが、３個以上としてもよい。 The example in which the concave portions 41 are provided at the four corner portions of the flat portion 13 has been described above. However, in the present invention, for example, as shown in FIG. It may be provided. In FIG. 5, two recesses 61 are illustrated, but three or more may be used.
　また、密閉型電池において、電池の内圧が異常上昇した際に、内圧を放出するベント機構が設けられていることが望ましい。電池が異常な高温に曝されたり、または短絡等を生じたりした際に、電池の内圧が瞬時に上昇することがある。その際に、ベント機構を作動させることにより、電池内のガスを放出して内圧を低下させる。 Also, in a sealed battery, it is desirable to provide a vent mechanism for releasing the internal pressure when the internal pressure of the battery abnormally increases. When the battery is exposed to an abnormally high temperature or when a short circuit occurs, the internal pressure of the battery may increase instantaneously. At that time, by operating the vent mechanism, the gas in the battery is released to reduce the internal pressure.
　電池の内圧を低下させるベント機構として、例えば、外装缶１０と蓋板２０との間の溶接部５０に設けられる溶接強度の低い脆弱部５１が挙げられる（図６参照）。この脆弱部５１は、電池の内圧が上昇した際に開裂して、電池内のガスを電池の外部に放出することで、電池の内圧上昇を防止することができる。 As a vent mechanism for reducing the internal pressure of the battery, for example, there is a fragile portion 51 having a low welding strength provided in the welded portion 50 between the outer can 10 and the cover plate 20 (see FIG. 6). The fragile portion 51 is cleaved when the internal pressure of the battery rises and releases the gas in the battery to the outside of the battery, thereby preventing the internal pressure of the battery from increasing.
　脆弱部５１は、電池ケース２の幅方向、すなわち蓋板２０の長手方向の少なくとも一方の端部に設けられる。また、脆弱部５１は、電池ケース２の厚み方向、すなわち蓋板２０の短手方向の少なくとも一側に設けられている。なお、図６の場合、脆弱部５１は、電池ケース２の左側（紙面左側）の背面（紙面奥側）に一つ設けられている。 The fragile portion 51 is provided in at least one end in the width direction of the battery case 2, that is, in the longitudinal direction of the lid plate 20. Further, the fragile portion 51 is provided on at least one side in the thickness direction of the battery case 2, that is, the short side direction of the lid plate 20. In the case of FIG. 6, one fragile portion 51 is provided on the back side (the back side of the drawing) of the left side (the left side of the drawing) of the battery case 2.
　溶接部５０は、レーザー溶接や抵抗溶接などによって溶接される。脆弱部５１は、溶接のビード幅を狭くしたり、溶接時の溶け込み深さを浅くしたりすることにより形成される。なお、レーザー溶接の場合には、例えば、溶接部５０の他の部分よりもレーザー光線の照射出力を小さくしたり、照射時間を短くしたりすることにより、脆弱部５１を形成することができる。 The weld 50 is welded by laser welding or resistance welding. The fragile portion 51 is formed by narrowing the weld bead width or reducing the penetration depth during welding. In the case of laser welding, for example, the weakened portion 51 can be formed by making the irradiation output of the laser beam smaller than other portions of the welded portion 50 or shortening the irradiation time.
　その他のベント機構としては、例えば、電池の内圧が上昇した際に開裂する開裂溝を、蓋板２０に設ける構成や外装缶１０の側面に設ける構成などがある。また、開裂溝の形状は、例えば、直線状、円弧状、Ｓ字状及び馬蹄鉄状など、電池の内圧に応じて開裂可能な形状であればどのような形状でもよい。さらに、ベント機構を複数、設けてもよい。 Other vent mechanisms include, for example, a configuration in which a cleaving groove that is cleaved when the internal pressure of the battery rises is provided in the lid plate 20 or a side surface of the outer can 10. In addition, the shape of the cleavage groove may be any shape as long as it can be cleaved according to the internal pressure of the battery, such as a linear shape, an arc shape, an S shape, and a horseshoe iron shape. Further, a plurality of vent mechanisms may be provided.
　本実施形態においては、正極３１及び負極３２の少なくともどちらか一方の表面に多孔性絶縁層が形成されていてもよい。正極及び負極の少なくとも一方の表面に、アルミナなどのフィラーを多孔性絶縁層として積層すると、電池の安全性が向上すること、繰り返しの充放電サイクルにおいて容量劣化が比較的少なくなること、などが知られている。しかし、充放電サイクルを繰り返すことによるガス発生や、電極の膨張・収縮により、外装缶が膨れてしまい、電極体の押さえつけがゆるくなって前記多孔性絶縁層が電極から脱落することがあった。多孔性絶縁層が電極から脱落すると、前述した本来の機能が著しく損なわれる問題があった。 In the present embodiment, a porous insulating layer may be formed on the surface of at least one of the positive electrode 31 and the negative electrode 32. It is known that when a filler such as alumina is laminated on at least one surface of the positive electrode and the negative electrode as a porous insulating layer, the safety of the battery is improved and the capacity deterioration is relatively reduced in repeated charge / discharge cycles. It has been. However, due to gas generation due to repeated charge / discharge cycles and expansion / contraction of the electrode, the outer can may swell, the electrode body may be loosely pressed, and the porous insulating layer may fall off the electrode. When the porous insulating layer is detached from the electrode, there is a problem that the above-described original function is remarkably impaired.
　本実施形態においては、前述した電解液に含まれるホスホノアセテート類の作用により、ガス発生を抑制しており、さらに、外装缶１０の側壁１２の平面部１３に形成した複数の凹部４１の存在により、外装缶の膨れを抑制しているので、多孔性絶縁層が電極から脱落する従来技術の問題を解決することができる。 In the present embodiment, the generation of gas is suppressed by the action of the phosphonoacetates contained in the electrolytic solution described above, and the presence of a plurality of recesses 41 formed in the flat portion 13 of the side wall 12 of the outer can 10. Thus, since the swelling of the outer can is suppressed, it is possible to solve the problem of the prior art in which the porous insulating layer is dropped from the electrode.
　正極３１の両方の表面に多孔性絶縁層が形成される場合は、図７Ａに示す通り、正極集電体３１ａの両面に形成した正極活物質層３１ｂそれぞれの表面３１１上に多孔性絶縁層３１ｃを形成する。あるいは、図７Ｂの通り、正極集電体３１ａの両面に形成された正極活物質層３１ｂのうち、どちらか片方の正極活物質層３１ｂの表面３１１に多孔性絶縁層３１ｃを形成してもよい。なお、図７Ａ及び図７Ｂの例では、正極集電体３１ａの両面に形成された正極活物質層３１ｂのうち、一方の正極活物質層３１ｂの表面３１１が正極３１における主面、他方の正極活物質層３１ｂの表面３１１が正極３１における主面の対向面に相当する。 When a porous insulating layer is formed on both surfaces of the positive electrode 31, as shown in FIG. 7A, a porous insulating layer 31c is formed on the surface 311 of each of the positive electrode active material layers 31b formed on both surfaces of the positive electrode current collector 31a. Form. Alternatively, as shown in FIG. 7B, the porous insulating layer 31c may be formed on the surface 311 of one of the positive electrode active material layers 31b formed on both surfaces of the positive electrode current collector 31a. . 7A and 7B, of the positive electrode active material layers 31b formed on both surfaces of the positive electrode current collector 31a, the surface 311 of one positive electrode active material layer 31b is the main surface of the positive electrode 31, and the other positive electrode The surface 311 of the active material layer 31 b corresponds to a surface facing the main surface of the positive electrode 31.
　前記多孔性絶縁層３１ｃは、例えば、母材となるフィラーと、必要に応じてバインダや増粘剤、分散剤等を水やＮＭＰなどの溶剤に分散させたペースト状やスラリー状の多孔性絶縁層含有組成物を調製し、これを正極活物質層３１ｂの表面に塗布し、乾燥することで形成される。 The porous insulating layer 31c is made of, for example, a paste-like or slurry-like porous insulation in which a filler as a base material and a binder, a thickener, a dispersant, etc. are dispersed in a solvent such as water or NMP as necessary. It is formed by preparing a layer-containing composition, applying it to the surface of the positive electrode active material layer 31b, and drying it.
　前記多孔性絶縁層３１ｃに用いられるフィラーは、電気絶縁性を有し、電気化学的にも安定であれば特に制限はなく、無機材料でもよいし、有機材料であってもよい。中でも耐熱温度が１５０℃以上のフィラーを含有することが望ましい。ここで、「耐熱温度が１５０℃以上」とは、少なくとも１５０℃において軟化などの変形が見られないこと意味する。前述した通り、電池が高温に曝された場合、セパレータが溶けて収縮し、正極及び負極で短絡を生じる可能性がある。よって、前記多孔性絶縁層３１ｃに、耐熱温度が１５０℃以上のフィラーを含有させることで、たとえセパレータが溶けて収縮しても、正極３１及び負極３２の少なくとも一方の主面及び／またはその対向面に形成した多孔性絶縁層３１ｃ，３２ｃの存在により、正極及び負極で短絡することを防止することができる。 The filler used for the porous insulating layer 31c is not particularly limited as long as it has electrical insulating properties and is electrochemically stable, and may be an inorganic material or an organic material. Among these, it is desirable to contain a filler having a heat resistant temperature of 150 ° C. or higher. Here, “the heat resistant temperature is 150 ° C. or higher” means that deformation such as softening is not observed at least at 150 ° C. As described above, when the battery is exposed to a high temperature, the separator melts and contracts, which may cause a short circuit between the positive electrode and the negative electrode. Therefore, by including a filler having a heat resistant temperature of 150 ° C. or higher in the porous insulating layer 31c, even if the separator melts and contracts, at least one main surface of the positive electrode 31 and the negative electrode 32 and / or the opposing surface thereof. The presence of the porous insulating layers 31c and 32c formed on the surface can prevent a short circuit between the positive electrode and the negative electrode.
　前記耐熱温度が１５０℃以上のフィラーのうち、無機材料としては、マグネシウム、アルミニウム、ケイ素、カルシウム、ジルコニウム、バリウム等の、元素周期表における、主に第３周期から第６周期の元素からなる酸化物、水酸化物、水酸化酸化物などがあげられる。有機材料としては、アクリレート系樹脂、架橋ポリスチレン、ポリイミド、メラミン樹脂、フェノール樹脂などがあげられる。また、これら無機材料及び有機材料は、それぞれを単独で用いてもよく、２種以上を併用して用いても構わない。 Among the fillers having a heat resistant temperature of 150 ° C. or higher, the inorganic material includes, for example, magnesium, aluminum, silicon, calcium, zirconium, barium, and the like, which are mainly composed of elements in the third to sixth periods in the periodic table of elements. Products, hydroxides, hydroxides and the like. Examples of the organic material include acrylate-based resins, cross-linked polystyrene, polyimide, melamine resins, and phenol resins. These inorganic materials and organic materials may be used alone or in combination of two or more.
　負極３２の両方の表面に多孔性絶縁層が形成される場合は、図８Ａに示す通り、負極集電体３２ａの両面に形成した負極活物質層３２ｂそれぞれの表面３２１上に多孔性絶縁層３２ｃを形成する。あるいは、図８Ｂの通り、負極集電体３２ａの両面に形成された負極活物質層３２ｂのうち、どちらか片方の負極活物質層３２ｂの表面３２１に多孔性絶縁層３２ｃを形成してもよい。なお、図８Ａ及び図８Ｂの例では、負極集電体３２ａの両面に形成された負極活物質層３２ｂのうち、一方の負極活物質層３２ｂの表面３２１が負極３２における主面、他方の負極活物質層３２ｂの表面３２１が負極３２における主面の対向面に相当する。 When the porous insulating layer is formed on both surfaces of the negative electrode 32, as shown in FIG. 8A, the porous insulating layer 32c is formed on the surface 321 of each of the negative electrode active material layers 32b formed on both surfaces of the negative electrode current collector 32a. Form. Alternatively, as shown in FIG. 8B, the porous insulating layer 32c may be formed on the surface 321 of one of the negative electrode active material layers 32b among the negative electrode active material layers 32b formed on both surfaces of the negative electrode current collector 32a. . 8A and 8B, among the negative electrode active material layers 32b formed on both surfaces of the negative electrode current collector 32a, the surface 321 of one negative electrode active material layer 32b is the main surface of the negative electrode 32, and the other negative electrode The surface 321 of the active material layer 32 b corresponds to a surface facing the main surface of the negative electrode 32.
　前記多孔性絶縁層３２ｃは、前記正極の多孔性絶縁層３１ｃを形成する場合と同様の手法で形成することができる。ただし、前記フィラーやバインダなど、多孔性絶縁層３２ｃを構成する物質は、必ずしも多孔性絶縁層３１ｃと同じでなくてもよく、例えば、多孔性絶縁層３１ｃで用いたフィラーとは別のフィラーを多孔性絶縁層３２ｃに用いてもよい。 The porous insulating layer 32c can be formed by the same method as that for forming the positive electrode porous insulating layer 31c. However, the material constituting the porous insulating layer 32c, such as the filler and the binder, is not necessarily the same as the porous insulating layer 31c. For example, a filler different from the filler used in the porous insulating layer 31c is used. You may use for the porous insulating layer 32c.
　（製造方法）
　次に、上述したように構成された密閉型電池１の製造方法について、図９を参照しつつ説明する。 (Production method)
Next, a manufacturing method of the sealed battery 1 configured as described above will be described with reference to FIG.
　まず、側面に凹部４１（６１）を有する外装缶１０を準備する（ステップＳ１）。具体的には、例えば、アルミニウム等の金属を原材料とし、上述のプレス成形等によって有底筒状の外装缶１０を作製する。プレス成形によって外装缶１を作製する場合は、上述した通り、プレスによって、凹部４１（６１）を外装缶１０の側面に同時に形成することが好ましい。しかしながら、凹部４１（６１）を有さない有底筒状の缶を成形した後で、この缶の側面に凹部を形成し、側面に凹部４１（６１）を有する有底筒状の外装缶１０を作製することもできる。なお、外装缶１０内の底面上には、上述した絶縁体１５（図２参照）を配置してもよい。 First, the outer can 10 having the concave portion 41 (61) on the side surface is prepared (step S1). Specifically, for example, a bottomed cylindrical outer can 10 is manufactured by using the metal such as aluminum as a raw material by the above press molding or the like. When producing the outer can 1 by press molding, as described above, it is preferable to simultaneously form the recess 41 (61) on the side surface of the outer can 10 by pressing. However, after molding a bottomed cylindrical can that does not have the recess 41 (61), a bottomed cylindrical outer can 10 having a recess on the side surface of the can and the recess 41 (61) on the side surface. Can also be produced. The insulator 15 (see FIG. 2) described above may be disposed on the bottom surface in the outer can 10.
　次に、上述した方法によって、正極３１を作製する（ステップＳ２）。作製された正極３１には、正極リード３４が接続される。また、上述した方法によって、負極３２を作製する（ステップＳ３）。作製された負極３５には、負極リード３５が接続される。 Next, the positive electrode 31 is produced by the method described above (step S2). A positive electrode lead 34 is connected to the manufactured positive electrode 31. Moreover, the negative electrode 32 is produced by the method described above (step S3). A negative electrode lead 35 is connected to the manufactured negative electrode 35.
　なお、外装缶の準備（ステップＳ１）、正極の作製（ステップＳ２）、及び負極の作製（ステップＳ３）を行う順序は、適宜入れ替えることができる。 Note that the order in which the outer can is prepared (step S1), the positive electrode is manufactured (step S2), and the negative electrode is manufactured (step S3) can be changed as appropriate.
　続いて、正極３１及び負極３２を用いて電極体３０を作製する（ステップＳ４）。詳述すると、正極３１と負極３２との間にセパレータ３３を配置し、正極３１、セパレータ３３、及び負極３２の積層体を渦巻状に巻回する。これにより、巻回構造を有する電極体３０が作製される。 Then, the electrode body 30 is produced using the positive electrode 31 and the negative electrode 32 (step S4). More specifically, the separator 33 is disposed between the positive electrode 31 and the negative electrode 32, and the laminate of the positive electrode 31, the separator 33, and the negative electrode 32 is wound in a spiral shape. Thereby, the electrode body 30 which has a winding structure is produced.
　このようにして作製した電極体３０の側面を押圧し、電極体３０を扁平状にした後、電極体３０を外装缶１０内に挿入する（ステップＳ５）。外装缶１０内の底面上に絶縁体１５が配置されている場合、電極体３０において、巻回方向に垂直な方向の端部の一方が絶縁体１５上に配置される。そして、上述した蓋板２０を準備し、図２に示すように、正極リード３４の先端を蓋板２０に接続するとともに、負極リード３５の先端を蓋板２０に設けられた負極端子２２に接続する。この状態で、外装缶１０の開口部の内側に蓋板２０を配置し、外装缶１０の内壁面と蓋板２０の外周縁部とを接合する。 The side surface of the electrode body 30 produced in this way is pressed to make the electrode body 30 flat, and then the electrode body 30 is inserted into the outer can 10 (step S5). When the insulator 15 is disposed on the bottom surface in the outer can 10, one end of the electrode body 30 in the direction perpendicular to the winding direction is disposed on the insulator 15. Then, the lid plate 20 described above is prepared, and as shown in FIG. 2, the tip of the positive electrode lead 34 is connected to the lid plate 20, and the tip of the negative electrode lead 35 is connected to the negative electrode terminal 22 provided on the lid plate 20. To do. In this state, the cover plate 20 is disposed inside the opening of the outer can 10, and the inner wall surface of the outer can 10 and the outer peripheral edge of the cover plate 20 are joined.
　次に、上述した方法によって電解液を調整し、外装缶１０に取り付けられた蓋板２０の注入口２４から電解液を注入する（ステップＳ６）。 Next, the electrolytic solution is adjusted by the above-described method, and the electrolytic solution is injected from the inlet 24 of the lid plate 20 attached to the outer can 10 (step S6).
　その後、注入口２４を封止栓２５で封止し、上述したように、注入口２４の周縁部に封止栓２５を接合することによって、外装缶１０を密閉する（ステップＳ７）。これにより、密閉型電池１が製造される。 Thereafter, the inlet 24 is sealed with the sealing plug 25, and the outer can 10 is sealed by joining the sealing plug 25 to the peripheral edge of the inlet 24 as described above (step S7). Thereby, the sealed battery 1 is manufactured.
　なお、図１０に示すように、作製された正極３１の少なくとも一方の表面３１１上に、上述した方法によって、多孔性絶縁層３１ｃを形成してもよい（ステップＳ８）。また、作製された負極３２の少なくとも一方の表面３２１上に、上述した方法によって、多孔性絶縁層３２ｃを形成してもよい。 As shown in FIG. 10, a porous insulating layer 31c may be formed on at least one surface 311 of the produced positive electrode 31 by the method described above (step S8). Further, the porous insulating layer 32c may be formed on at least one surface 321 of the manufactured negative electrode 32 by the method described above.
　多孔性絶縁層３１ｃ，３２ｃは、正極３１及び負極３２の少なくとも一方に形成されればよい。 The porous insulating layers 31 c and 32 c may be formed on at least one of the positive electrode 31 and the negative electrode 32.
　多孔性絶縁層３１ｃを正極３１のみに設ける場合は、正極３１を作製した（ステップＳ２）後であって、電極体３０を作製する（ステップＳ４）前に多孔性絶縁層３１ｃを形成すればよい（ステップＳ８）。正極３１の作製（ステップＳ１）及び多孔性絶縁層３１ｃの形成（ステップＳ８）を、外装缶の準備（ステップＳ１）の前に行うこともできる。 When the porous insulating layer 31c is provided only on the positive electrode 31, the porous insulating layer 31c may be formed after the positive electrode 31 is manufactured (step S2) and before the electrode body 30 is manufactured (step S4). (Step S8). The production of the positive electrode 31 (step S1) and the formation of the porous insulating layer 31c (step S8) can also be performed before the preparation of the outer can (step S1).
　多孔性絶縁層３２ｃを負極３２のみに設ける場合は、負極３２を作製した（ステップＳ３）後であって、電極体３０を作製する（ステップＳ４）前に多孔性絶縁層３２ｃを形成すればよい（ステップＳ８）。負極３２の作製（ステップＳ３）及び多孔性絶縁層３１ｃの形成（ステップＳ８）を、外装缶の準備（ステップＳ１）や正極３１の作製（ステップＳ１）の前に行うこともできる。 When the porous insulating layer 32c is provided only on the negative electrode 32, the porous insulating layer 32c may be formed after the negative electrode 32 is manufactured (step S3) and before the electrode body 30 is manufactured (step S4). (Step S8). The production of the negative electrode 32 (step S3) and the formation of the porous insulating layer 31c (step S8) can also be performed before the preparation of the outer can (step S1) and the production of the positive electrode 31 (step S1).
　（実施例１）
　＜正極の作製＞
　正極活物質としてのＬｉ１．０２Ｎｉ０．５Ｃｏ０．２Ｍｎ０．３Ｏ２：（５０質量部）及びＬｉＣｏＯ２（５０質量部）と、バインダであるポリフッ化ビニリデン（ＰＶｄＦ）を１０質量％含有したＮ－メチル－２－ピロリドン（ＮＭＰ）の溶液：２０質量部と、導電助剤である人造黒鉛：１質量部及びケッチェンブラック：１質量部とを、二軸混練機を用いて混練した。その後、混練されたものにＮＭＰを加えて粘度を調節することにより、正極合剤含有ペーストを調製した。この正極合剤含有ペーストを、厚みが１５μｍのアルミニウム箔（正極集電体）の両面に、厚みを調整しながら間欠塗布して、乾燥させた。その後、カレンダー処理を行って全厚が１３０μｍになるように正極合剤層の厚みを調整し、幅が４２ｍｍになるように切断することにより、正極を作製した。そして、この正極のアルミニウム箔の露出部に正極タブを溶接することにより、正極のリード部を形成した。 (Example 1)
<Preparation of positive electrode>
Li 1.02 Ni 0.5 Co 0.2 Mn 0.3 O 2 as positive electrode active material : (50 parts by mass) and LiCoO 2 (50 parts by mass), and 10 % of polyvinylidene fluoride (PVdF) as a binder N-methyl-2-pyrrolidone (NMP) solution containing 20% by mass: 20 parts by mass of artificial graphite as a conductive additive: 1 part by mass and ketjen black: 1 part by mass using a biaxial kneader And kneaded. Thereafter, NMP was added to the kneaded mixture to adjust the viscosity, thereby preparing a positive electrode mixture-containing paste. This positive electrode mixture-containing paste was intermittently applied to both surfaces of an aluminum foil (positive electrode current collector) having a thickness of 15 μm while adjusting the thickness, and dried. Thereafter, calendar treatment was performed to adjust the thickness of the positive electrode mixture layer so that the total thickness was 130 μm, and the positive electrode was produced by cutting so that the width was 42 mm. And the lead part of the positive electrode was formed by welding the positive electrode tab to the exposed part of the aluminum foil of this positive electrode.
　＜負極の作製＞
　負極活物質として、ＳｉＯの表面を炭素材料で被覆した複合体（複合体における炭素材料の量が２０質量％、平均粒径が５μｍ。以下、「ＳｉＯ／炭素材料複合体」という。）及び平均粒子径が１６μｍである黒鉛をＳｉＯ／炭素材料複合体の量が５．０質量％となる量で混合したもの：９７．５質量％、ＳＢＲ：１．５質量％、及びカルボキシメチルセルロース（増粘剤）：１質量％を、水を用いて混合して負極合剤層形成用スラリーを調製した。この負極合剤層形成用スラリーを、集電体である銅箔（厚み：８μｍ）の両面に塗布して、１２０℃で１２時間真空乾燥を施した。そして、プレス処理を行うことにより、全厚が１１０μｍになるように負極合剤層の厚みを調整した。その後、幅が４３ｍｍになるように切断することにより、負極を作製した。この負極の銅箔の露出部にタブを溶接することにより、負極のリード部を形成した。 <Production of negative electrode>
As a negative electrode active material, a composite in which the surface of SiO is coated with a carbon material (the amount of the carbon material in the composite is 20 mass%, the average particle size is 5 μm, hereinafter referred to as “SiO / carbon material composite”) and the average Graphite having a particle size of 16 μm mixed with SiO / carbon material composite in an amount of 5.0% by mass: 97.5% by mass, SBR: 1.5% by mass, and carboxymethyl cellulose (thickening Agent): 1% by mass was mixed with water to prepare a slurry for forming a negative electrode mixture layer. This slurry for forming a negative electrode mixture layer was applied to both sides of a copper foil (thickness: 8 μm) as a current collector, and vacuum dried at 120 ° C. for 12 hours. And the thickness of the negative mix layer was adjusted so that the total thickness might be 110 micrometers by performing a press process. Then, the negative electrode was produced by cut | disconnecting so that a width | variety might be set to 43 mm. A negative electrode lead portion was formed by welding a tab to the exposed portion of the negative electrode copper foil.
　＜セパレータの作製＞
　変性ポリブチルアクリレートの樹脂バインダ：３質量部と、ベーマイト粉末（平均粒径１μｍ）：９７質量部と、水：１００質量部とを混合して、絶縁層形成スラリーを作製した。この絶縁層形成スラリーを、リチウムイオン電池用ポリエチレン製微多孔膜（厚さ１４μｍ）の片面に塗布し（塗布厚さは２μｍ）、乾燥させることにより、セパレータを得た。 <Preparation of separator>
A resin binder of modified polybutyl acrylate: 3 parts by mass, boehmite powder (average particle size 1 μm): 97 parts by mass, and water: 100 parts by mass were mixed to prepare an insulating layer forming slurry. This insulating layer forming slurry was applied to one side of a polyethylene microporous membrane (thickness 14 μm) for lithium ion batteries (application thickness was 2 μm) and dried to obtain a separator.
　＜外装缶の作製＞
　図１に示す外観を有し、平面部の横寸法が５１ｍｍ、縦寸法が４８ｍｍ、板厚みが０．３ｍｍ、見掛け厚みが５．０５ｍｍのアルミニウム製外装缶を作製した。その際、外装缶の四角の端部に、正方形状の凹部４１を形成した。なお、凹部は、側壁部の面方向の長さが０．５ｍｍ、凹部の深さが０．２ｍｍ、凹部の一辺の長さが９ｍｍとした。 <Preparation of outer can>
An aluminum outer can having the appearance shown in FIG. 1 and having a horizontal dimension of 51 mm, a vertical dimension of 48 mm, a plate thickness of 0.3 mm, and an apparent thickness of 5.05 mm was produced. At that time, a square recess 41 was formed at the square end of the outer can. In addition, the recessed part made the length of the surface direction of a side wall part 0.5 mm, the depth of the recessed part 0.2 mm, and the length of one side of the recessed part 9 mm.
　＜電解液の作製＞
　上述の正極及び負極を、セパレータを介して重ね合わせた状態で渦巻状に巻回することにより、巻回構造を有する巻回電極体を作製した。この巻回電極体を押しつぶして扁平状にした後、前記外装缶内に挿入した。さらに、エチレンカーボネートとエチルメチルカーボネートとジエチルカーボネートとを体積比＝１：１：１で混合した溶媒に、ＬｉＰＦ６を１．１ｍｏｌ／ｌの濃度になるように溶解させた。これに、４－フルオロ－１，３－ジオキソラン－２－オンを、１．５質量％となる量で添加し、ビニレンカーボネートを、２．０質量％となる量で添加し、さらに、２－プロピニル２－（ジエトキシホスホリル）アセテートを１．５質量％となる量で添加した。このように作製された電解液を、前記外装缶内に注入した。 <Preparation of electrolyte>
The above-described positive electrode and negative electrode were wound in a spiral shape in a state of being overlapped via a separator, thereby producing a wound electrode body having a wound structure. The wound electrode body was crushed into a flat shape and then inserted into the outer can. Furthermore, LiPF 6 was dissolved in a solvent in which ethylene carbonate, ethyl methyl carbonate, and diethyl carbonate were mixed at a volume ratio = 1: 1: 1 so as to have a concentration of 1.1 mol / l. To this, 4-fluoro-1,3-dioxolan-2-one was added in an amount of 1.5% by mass, vinylene carbonate was added in an amount of 2.0% by mass, and 2- Propinyl 2- (diethoxyphosphoryl) acetate was added in an amount of 1.5% by weight. The electrolytic solution thus prepared was injected into the outer can.
　＜密閉型電池の作製＞
　巻回電極体及び電解液が収納された外装缶の開口部周縁と、蓋体の外周縁とを溶接することにより、図１に示すような密閉型電池を作製した。なお、溶接の際に、部分的に溶接強度を低下させることにより、脆弱部を形成した。具体的には、溶接の際にレーザー光の照射強度を調整して、脆弱部の溶け込み深さを０．１ｍｍ、それ以外の溶接部の溶け込み深さを０．１８ｍｍとした。 <Production of sealed battery>
A sealed battery as shown in FIG. 1 was produced by welding the peripheral edge of the opening of the outer can in which the wound electrode body and the electrolytic solution were stored, and the outer peripheral edge of the lid. In the welding, the weakened part was formed by partially reducing the welding strength. Specifically, the laser beam irradiation intensity was adjusted at the time of welding so that the penetration depth of the weakened portion was 0.1 mm, and the penetration depth of the other welded portions was 0.18 mm.
　（実施例２）
　２－プロピニル２－（ジエトキシホスホリル）アセテートの代わりに、トリエチルホスホノアセテートを添加した電解液を用いた以外は、すべて実施例１と同様に密閉型電池を作製した。 (Example 2)
A sealed battery was fabricated in the same manner as in Example 1 except that an electrolytic solution to which triethylphosphonoacetate was added instead of 2-propynyl 2- (diethoxyphosphoryl) acetate was used.
　（実施例３）
　２－プロピニル２－（ジエトキシホスホリル）アセテートの代わりに、アリルジエチルホスホノアセテートを添加した電解液を用いた以外は、すべて実施例１と同様に密閉型電池を作製した。 (Example 3)
A sealed battery was produced in the same manner as in Example 1 except that an electrolytic solution to which allyl diethylphosphonoacetate was added instead of 2-propynyl 2- (diethoxyphosphoryl) acetate was used.
　（実施例４）
　ＳｉＯ／炭素材料複合体の量を５．０質量％から３．０質量％とした点、Ｌｉ１．０２Ｎｉ０．５Ｃｏ０．２Ｍｎ０．３Ｏ２を５０質量部から３０質量部（ＬｉＣｏＯ２は７０質量部）とした点、電解液に添加した２－プロピニル２－（ジエトキシホスホリル）アセテートの量を１．５重量％から１．０質量％とした点以外は、すべて実施例１と同様に密閉型電池を作製した。 Example 4
Point was 3.0 wt% the amount of SiO / carbon material composite from 5.0 wt%, Li 1.02 Ni 0.5 Co 0.2 Mn 0.3 O 2 30 parts by weight from 50 parts by weight (LiCoO 2 was 70 parts by mass) and all the steps were performed except that the amount of 2-propynyl 2- (diethoxyphosphoryl) acetate added to the electrolyte was changed from 1.5% by weight to 1.0% by weight. A sealed battery was produced in the same manner as in Example 1.
　（実施例５）
　ＳｉＯ／炭素材料複合体の量を５．０質量％から８．０質量％とした点、Ｌｉ１．０２Ｎｉ０．５Ｃｏ０．２Ｍｎ０．３Ｏ２を５０質量部から６０質量部（ＬｉＣｏＯ２は４０質量部）とした点、電解液に添加した２－プロピニル２－（ジエトキシホスホリル）アセテートの量を１．５重量％から２．０質量％とした点以外は、すべて実施例１と同様に密閉型電池を作製した。 (Example 5)
Point was 8.0 wt% the amount of SiO / carbon material composite from 5.0 wt%, Li 1.02 Ni 0.5 Co 0.2 Mn 0.3 O 2 60 parts by mass from 50 parts by weight (LiCoO 2 was 40 parts by mass) and all the steps were performed except that the amount of 2-propynyl 2- (diethoxyphosphoryl) acetate added to the electrolyte was changed from 1.5% by weight to 2.0% by weight. A sealed battery was produced in the same manner as in Example 1.
　（実施例６）
　ＳｉＯ／炭素材料複合体の量を５．０質量％から１０．０質量％とした点、Ｌｉ１．０２Ｎｉ０．５Ｃｏ０．２Ｍｎ０．３Ｏ２を５０質量部から７０質量部（ＬｉＣｏＯ２は３０質量部）とした点、電解液に添加した２－プロピニル２－（ジエトキシホスホリル）アセテートの量を１．５重量％から３．０質量％とした点以外は、すべて実施例１と同様に密閉型電池を作製した。 (Example 6)
Point was 10.0 wt% the amount of SiO / carbon material composite from 5.0 wt%, Li 1.02 Ni 0.5 Co 0.2 Mn 0.3 O 2 to 70 parts by mass 50 parts by weight Except for the point that LiCoO 2 was 30 parts by mass and the amount of 2-propynyl 2- (diethoxyphosphoryl) acetate added to the electrolyte was 1.5% to 3.0% by mass A sealed battery was produced in the same manner as in Example 1.
　（実施例７）
　平面部の横寸法が５１ｍｍ、縦寸法が４８ｍｍ、板厚みが０．３ｍｍ、見掛け厚みが５．０５ｍｍのアルミニウム製外装缶の四角のうち上側の二箇所に、凹部を形成した。なお、凹部の仕様は実施例１と同様とした。また、電解液に添加した２－プロピニル２－（ジエトキシホスホリル）アセテートの量を１．５重量％から２．０質量％とした。以上の変更を除けば、すべて実施例１と同様に密閉型電池を作製した。 (Example 7)
Concave portions were formed in two upper portions of the square of the aluminum outer can having a horizontal dimension of 51 mm, a vertical dimension of 48 mm, a plate thickness of 0.3 mm, and an apparent thickness of 5.05 mm. The specifications of the recesses were the same as in Example 1. Further, the amount of 2-propynyl 2- (diethoxyphosphoryl) acetate added to the electrolytic solution was adjusted from 1.5% by weight to 2.0% by weight. Except for the above changes, a sealed battery was produced in the same manner as in Example 1.
　（実施例８）
　平面部の横寸法が５１ｍｍ、縦寸法が４８ｍｍ、板厚みが０．３ｍｍ、見掛け厚みが５．０５ｍｍのアルミニウム製外装缶の中央部の２箇所に凹部を形成した。なお、凹部は、側壁部の面方向の長さが０．５ｍｍ、凹部の深さが０．２ｍｍ、凹部の横寸法が７ｍｍ、凹部の縦寸法が３５ｍｍとした。以上の外装缶を用いた以外は、すべて実施例１と同様にして密閉型電池を作製した。 (Example 8)
Concave portions were formed at two locations in the center of the aluminum outer can having a horizontal dimension of 51 mm, a vertical dimension of 48 mm, a plate thickness of 0.3 mm, and an apparent thickness of 5.05 mm. In addition, as for the recessed part, the length of the surface direction of the side wall part was 0.5 mm, the depth of the recessed part was 0.2 mm, the horizontal dimension of the recessed part was 7 mm, and the vertical dimension of the recessed part was 35 mm. A sealed battery was produced in the same manner as in Example 1 except that the above outer can was used.
　（実施例９）
　蓋板２０に開裂ベントを設ける一方、蓋板２０と外装缶１０との溶接部分には脆弱部を形成しなかった点以外は、すべて実施例１と同様にして密閉型電池を作製した。 Example 9
A sealed battery was fabricated in the same manner as in Example 1 except that a cleaving vent was provided on the lid plate 20 and no fragile portion was formed at the welded portion between the lid plate 20 and the outer can 10.
　（実施例１０）
　バインダであるポリフッ化ビニリデン（ＰＶｄＦ）を５質量％含有したＮ－メチル－２－ピロリドン（ＮＭＰ）の溶液：１００質量部と、ベーマイト粉末（平均粒径１μｍ）：１００質量部とを混合して、多孔性絶縁層形成スラリーを作製した。この多孔性絶縁層形成スラリーを、実施例１で用いたカレンダー処理後の正極（全厚が１３０μｍ）の両面に塗布し（塗布厚さは両面とも３μｍ）、乾燥させることにより、正極の両面に多孔性絶縁層を形成させた。さらに幅が４２ｍｍになるように切断することにより、正極を作製した。以下、セパレータとしてリチウムイオン電池用ポリエチレン製微多孔膜（厚さ１２μｍ）を用いたこと以外は、すべて実施例１と同様にして密閉型電池を作製した。 (Example 10)
A solution of N-methyl-2-pyrrolidone (NMP) containing 5% by mass of polyvinylidene fluoride (PVdF) as a binder: 100 parts by mass and boehmite powder (average particle size 1 μm): 100 parts by mass were mixed. A porous insulating layer forming slurry was prepared. This porous insulating layer-forming slurry was applied to both sides of the calendered positive electrode (total thickness 130 μm) used in Example 1 (the coating thickness was 3 μm on both sides) and dried to form both sides of the positive electrode. A porous insulating layer was formed. Furthermore, the positive electrode was produced by cut | disconnecting so that a width | variety might be set to 42 mm. Thereafter, a sealed battery was produced in the same manner as in Example 1 except that a polyethylene microporous membrane for lithium ion batteries (thickness: 12 μm) was used as the separator.
　（実施例１１）
　バインダであるポリフッ化ビニリデン（ＰＶｄＦ）を５質量％含有したＮ－メチル－２－ピロリドン（ＮＭＰ）の溶液：１００質量部と、ベーマイト粉末（平均粒径１μｍ）：１００質量部とを混合して、多孔性絶縁層形成スラリーを作製した。この多孔性絶縁層形成スラリーを、実施例１で用いたカレンダー処理後の負極（全厚が１１０μｍ）の両面に塗布し（塗布厚さは両面とも３μｍ）、乾燥させることにより、負極の両面に多孔性絶縁層を形成させた。さらに幅が４３ｍｍになるように切断することにより、負極を作製した。以下、セパレータとしてリチウムイオン電池用ポリエチレン製微多孔膜（厚さ１２μｍ）を用いたこと以外は、すべて実施例１と同様にして密閉型電池を作製した。 (Example 11)
A solution of N-methyl-2-pyrrolidone (NMP) containing 5% by mass of polyvinylidene fluoride (PVdF) as a binder: 100 parts by mass and boehmite powder (average particle size 1 μm): 100 parts by mass were mixed. A porous insulating layer forming slurry was prepared. This porous insulating layer-forming slurry was applied to both sides of the calendered negative electrode (total thickness 110 μm) used in Example 1 (the coating thickness was 3 μm on both sides) and dried to form both sides of the negative electrode A porous insulating layer was formed. Furthermore, the negative electrode was produced by cut | disconnecting so that a width | variety might be set to 43 mm. Thereafter, a sealed battery was produced in the same manner as in Example 1 except that a polyethylene microporous membrane for lithium ion batteries (thickness: 12 μm) was used as the separator.
　（比較例１）
　正極にＬｉ１．０２Ｎｉ０．５Ｃｏ０．２Ｍｎ０．３Ｏ２を用いずに、ＬｉＣｏＯ２のみを正極活物質として用いた点、及び、負極にＳｉＯ／炭素材料複合体を用いずに、負極活物質をすべて平均粒子径が１６μｍの黒鉛とした点以外は、すべて実施例１と同様にして密閉型電池を作製した。 (Comparative Example 1)
Without using Li 1.02 Ni 0.5 Co 0.2 Mn 0.3 O 2 for the positive electrode, using only LiCoO 2 as the positive electrode active material, and without using the SiO / carbon material composite for the negative electrode In addition, a sealed battery was fabricated in the same manner as in Example 1 except that the negative electrode active material was all graphite having an average particle diameter of 16 μm.
　（比較例２）
　外装缶に凹部を設けていない点以外は、すべて実施例１と同様にして密閉型電池を作製した。 (Comparative Example 2)
A sealed battery was produced in the same manner as Example 1 except that the outer can was not provided with a recess.
　（比較例３）
　２－プロピニル２－（ジエトキシホスホリル）アセテートを添加していない電解液を用いた点以外は、すべて実施例１と同様にして密閉型電池を作製した。 (Comparative Example 3)
A sealed battery was fabricated in the same manner as in Example 1 except that an electrolytic solution to which 2-propynyl 2- (diethoxyphosphoryl) acetate was not added was used.
　（比較例４）
　２－プロピニル２－（ジエトキシホスホリル）アセテートの代わりに、１，３－プロパンスルトンを添加した電解液を用いた以外は、すべて実施例１と同様に密閉型電池を作製した。 (Comparative Example 4)
A sealed battery was fabricated in the same manner as in Example 1 except that an electrolytic solution added with 1,3-propane sultone was used instead of 2-propynyl 2- (diethoxyphosphoryl) acetate.
　さらに各実施例及び各比較例で作製した密閉型電池について、下記の方法によって電池容量、充放電サイクル試験、電池膨れの評価をそれぞれ行った。その結果を表１に示す。
Furthermore, the battery capacity, the charge / discharge cycle test, and the battery swelling were evaluated by the following methods for the sealed batteries prepared in each Example and each Comparative Example. The results are shown in Table 1.
　＜電池容量＞
　密閉型電池の初回充放電後、２３℃の環境下で、１Ｃの定電流で４．２Ｖに達するまで充電を行った後、４．２Ｖの定電圧で充電する、定電流－定電圧充電（総充電時間：２．５時間）を行った。そして、０．２Ｃの定電流放電（放電終止電圧：３．０Ｖ）を行い、得られた放電容量（ｍＡｈ）を電池容量とした。表１では、各実施例及び各比較例で測定した放電容量（電池容量）を比較例１の放電容量（電池容量）で除した値を、相対値（％）として示している。　 <Battery capacity>
After the initial charge / discharge of the sealed battery, the battery is charged at a constant current of 1C until reaching 4.2V in an environment of 23 ° C., and then charged at a constant voltage of 4.2V. Total charging time: 2.5 hours). And 0.2 C constant current discharge (discharge end voltage: 3.0V) was performed, and the obtained discharge capacity (mAh) was defined as the battery capacity. In Table 1, the value which remove | divided the discharge capacity (battery capacity) measured by each Example and each comparative example by the discharge capacity (battery capacity) of the comparative example 1 is shown as a relative value (%).
　＜充放電サイクル試験＞
　２３℃の環境下で、１．０Ｃの電流値で電池電圧が４．２Ｖになるまで定電流充電を行った後、４．２Ｖで定電圧充電を行う、定電流－定電圧充電を行った。充電終了までの総充電時間は２．５時間とした。その後、１．０Ｃの電流値で電池電圧が３．０Ｖに到達するまで定電流放電を行った。このような充放電を１サイクルとして、充放電を繰り返して、１サイクル目の放電容量に対して８０％の放電容量となったサイクル数を調べた。
<Charge / discharge cycle test>
In a 23 ° C. environment, constant current charging was performed until the battery voltage reached 4.2 V at a current value of 1.0 C, then constant voltage charging was performed at 4.2 V, and constant current-constant voltage charging was performed. . The total charging time until the end of charging was 2.5 hours. Thereafter, constant current discharge was performed until the battery voltage reached 3.0 V at a current value of 1.0 C. Such charging / discharging was made into 1 cycle, charging / discharging was repeated and the cycle number which became 80% of discharge capacity with respect to the discharge capacity of the 1st cycle was investigated.
　＜電池膨れ＞
　密閉型電池の初回充放電後、上述の電池容量の測定と同じ条件で密閉型電池の充電を行った。密閉型電池の充電を行った後、外装缶の厚さＴ１を測定した。その後、８５℃に設定された恒温槽内で密閉型電池を２４時間保存した後、恒温槽から取り出して、常温で３時間放置後に、再び外装缶の厚さＴ２を測定した。なお、本試験でいう外装缶の厚さとは、外装缶の平面部（幅広側面）間の厚さを意味する。外装缶の厚さ測定は、ノギス（例えば、ミツトヨ社製；ＣＤ－１５ＣＸ）を用いて、平面部の中央部を、１００分の１ｍｍ単位で計測した。電池膨れ（％）は、下記式により求めた。 <Battery swelling>
After the initial charge / discharge of the sealed battery, the sealed battery was charged under the same conditions as the above-described measurement of the battery capacity. After charging of the sealed battery was measured thickness T 1 of the outer can. Thereafter, the sealed battery was stored in a thermostat set at 85 ° C. for 24 hours, then taken out of the thermostat and allowed to stand at room temperature for 3 hours, and then the thickness T 2 of the outer can was measured again. The thickness of the outer can in the present test means the thickness between the flat portions (wide side surfaces) of the outer can. The thickness of the outer can was measured using a caliper (for example, Mitutoyo Corp .; CD-15CX) at the center of the flat surface in units of 1/100 mm. The battery swelling (%) was obtained by the following formula.
　電池膨れ（％）＝１００×（Ｔ２－Ｔ１）／（Ｔ１）　 Battery swelling (%) = 100 × (T 2 −T 1 ) / (T 1 )
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
　表１から、負極にＳｉＯ／炭素材料複合体を用いるとともに、ホスホノアセテート類化合物が添加された電解液を用いた場合（実施例１～１１）には、それらを用いなかった場合（比較例１～４）に比べて、電池の充放電サイクル特性が高く且つ電池容量も大きい。また、実施例１～１１の方が、比較例２，３に対して電池膨れも小さかった。特に、２－プロピニル２－（ジエトキシホスホリル）アセテートが適量、添加された電解液を用いた場合（実施例１、２、１０、１１）には、高い電池性能を有しつつ、最も電池の膨れを抑制することができた。 From Table 1, when using the electrolyte solution to which the phosphonoacetate compound was added while using the SiO / carbon material composite for the negative electrode (Examples 1 to 11), when not using them (Comparative Example) Compared with 1 to 4), the charge / discharge cycle characteristics of the battery are high and the battery capacity is also large. Further, in Examples 1 to 11, the battery swelling was smaller than those in Comparative Examples 2 and 3. In particular, when an electrolyte containing an appropriate amount of 2-propynyl 2- (diethoxyphosphoryl) acetate was used (Examples 1, 2, 10, and 11), while having high battery performance, Swelling could be suppressed.
　しかも、上述の実施例１～１１のように密閉型電池の外装缶に凹部を設けることにより、凹部を設けない場合（比較例２）に比べて電池膨れを効果的に抑制することができる。 In addition, by providing a recess in the outer can of the sealed battery as in Examples 1 to 11 described above, it is possible to effectively suppress battery swelling compared to the case where no recess is provided (Comparative Example 2).
　したがって、負極にＳｉＯ／炭素材料複合体を用いるとともに、ホスホノアセテート類化合物が添加された電解液を用いて、外装缶に凹部を設けることにより、電池性能の向上と電池の膨れ防止との両立を図ることが可能になる。 Therefore, using a SiO / carbon material composite for the negative electrode and using an electrolytic solution to which a phosphonoacetate compound has been added to provide a recess in the outer can, both improving battery performance and preventing battery swelling Can be achieved.
　（実施形態の効果）
　本実施形態では、負極がＳｉとＯとを構成元素に含む材料を有し、電解液として、２－プロピニル２－（ジエトキシホスホリル）アセテート、トリエチルホスホノアセテートなどのホスホノアセテート類化合物が添加された電解液を用いる。これにより、遷移金属としてニッケルを含むリチウム含有複合酸化物を正極活物質として有する密閉型電池において、電池ケース２の内圧が上昇した場合に、電池ケース２内でのガス発生を抑制することができる。 (Effect of embodiment)
In this embodiment, the negative electrode has a material containing Si and O as constituent elements, and a phosphonoacetate compound such as 2-propynyl 2- (diethoxyphosphoryl) acetate or triethylphosphonoacetate is added as an electrolyte. The electrolyte solution used is used. Accordingly, in a sealed battery having a lithium-containing composite oxide containing nickel as a transition metal as a positive electrode active material, gas generation in the battery case 2 can be suppressed when the internal pressure of the battery case 2 increases. .
　しかも、本実施形態では、電池ケース２の平面部１３の角部分で、且つ、平面部１３の角部分から中央部分へと延びる直線Ｌ上に、該電池ケース２の内方に向かって凹んだ凹部４１を設ける。これにより、電池ケース２の内圧が上昇した場合、凹部４１によって、電池ケース２の変形を抑制することができる。 Moreover, in the present embodiment, the battery case 2 is recessed toward the inside of the battery case 2 on the straight line L extending from the corner part of the flat part 13 to the central part at the corner part of the flat part 13. A recess 41 is provided. Thereby, when the internal pressure of battery case 2 rises, deformation of battery case 2 can be suppressed by recess 41.
　また、凹部４１を、その角部分４１ｃが前記直線Ｌ上に位置するように平面部１３に設けることで、該平面部１３の変形を凹部４１によってより確実に阻害することができる。したがって、電池ケース２の変形をより確実に抑制することができる。 Further, by providing the concave portion 41 on the flat surface portion 13 so that the corner portion 41c is positioned on the straight line L, deformation of the flat surface portion 13 can be more reliably inhibited by the concave portion 41. Therefore, deformation of the battery case 2 can be more reliably suppressed.
　さらに、凹部４１を、その角部分４１ｃが直線Ｌ上で且つ該凹部４１において平面部１３の角部分側に位置するように、該平面部１３に形成することで、平面部１３の変形を初期段階で抑制することができる。したがって、電池ケース２の変形をさらに確実に抑制することができる。 Further, the concave portion 41 is formed in the flat portion 13 so that the corner portion 41c is located on the straight line L and on the corner portion side of the flat portion 13 in the concave portion 41, so that the deformation of the flat portion 13 is initially performed. Can be suppressed in stages. Therefore, the deformation of the battery case 2 can be further reliably suppressed.
　しかも、凹部４１を、平面部１３の四角にそれぞれ設けることで、平面部１３の変形をさらに確実に抑制することができる。これにより、電池ケース２の変形をさらに確実に抑制することができる。 In addition, by providing the concave portions 41 at the squares of the plane portion 13, the deformation of the plane portion 13 can be further reliably suppressed. Thereby, the deformation | transformation of the battery case 2 can be suppressed more reliably.
　（その他の実施形態）
　以上、本発明の実施の形態を説明したが、上述した実施の形態は本発明を実施するための例示に過ぎない。よって、上述した実施の形態に限定されることなく、その趣旨を逸脱しない範囲内で上述した実施の形態を適宜変形して実施することが可能である。 (Other embodiments)
While the embodiments of the present invention have been described above, the above-described embodiments are merely examples for carrying out the present invention. Therefore, the present invention is not limited to the above-described embodiment, and the above-described embodiment can be appropriately modified and implemented without departing from the spirit of the invention.
　前記各実施形態では、密閉型電池１の電池ケース２を、長方形の短辺側が円弧状に形成された底面を有する柱状としている。しかしながら、電池ケースの形状は、六面体など他の形状であってもよい。 In each of the above embodiments, the battery case 2 of the sealed battery 1 has a columnar shape having a bottom surface in which the rectangular short side is formed in an arc shape. However, the shape of the battery case may be other shapes such as a hexahedron.
　前記各実施形態では、電池ケース２は一対の対向する平面部１３（側面）を有し、各平面部１３に凹部４１が形成されていたが、特にこれに限定されるものではない。例えば、電池ケースの一対の対向する側面の一方にのみ、凹部を形成してもよい。また、電池ケースが三角筒状に形成される等、電池ケースが一対の対向する側面を有しない場合であっても、電池ケースの側面のどこかに凹部が形成されていればよい。 In each of the above embodiments, the battery case 2 has a pair of opposed flat portions 13 (side surfaces), and the concave portions 41 are formed in the flat portions 13, but the present invention is not particularly limited thereto. For example, you may form a recessed part only in one side of a pair of opposing side surface of a battery case. In addition, even when the battery case does not have a pair of opposing side surfaces, such as when the battery case is formed in a triangular cylinder shape, it is only necessary that a recess be formed somewhere on the side surface of the battery case.
　前記各実施形態では、電池ケース２の平面部１３（側面）は矩形状であったが、電池ケースの側面は、矩形状以外の多角形状や、円形状、または楕円形状などであってもよい。また、電池ケースの側面を多角形状（矩形状を含む）に形成した後、側面の角部の一部を面取り加工するなど、電池ケースの側面を種々の形状とすることができる。 In each of the embodiments described above, the flat surface portion 13 (side surface) of the battery case 2 has a rectangular shape, but the side surface of the battery case may have a polygonal shape other than the rectangular shape, a circular shape, an elliptical shape, or the like. . Moreover, after forming the side surface of the battery case into a polygonal shape (including a rectangular shape), the side surface of the battery case can be formed into various shapes such as chamfering a part of the corners of the side surface.
　本発明は、電極体及び電解液が収納される電池ケースを備えた密閉型電池に利用可能である。 The present invention can be used for a sealed battery including a battery case in which an electrode body and an electrolytic solution are stored.

Claims (15)

  1. 　正極及び負極を有する電極体と、
    　電解液と、
    　内部に前記電極体及び前記電解液が封入される電池ケースとを備え、
    　前記正極は、正極活物質として、リチウム及び遷移金属を含むリチウム含有複合酸化物が用いられ、
    　前記リチウム含有複合酸化物の少なくとも一部は、遷移金属としてニッケルを含み、
    　前記負極は、負極活物質として、Ｓｉ及びＯを構成元素に含む材料（ただし、Ｓｉに対するＯの原子比ｘは、０．５≦ｘ≦１．５）と黒鉛質炭素材料とを含み、
    　前記電解液は、ホスホノアセテート類化合物を含有し、
    　前記電池ケースの側面には、該電池ケースの内方に向かって凹んだ凹部が形成されている、密閉型電池。     An electrode body having a positive electrode and a negative electrode;
    An electrolyte,
    A battery case in which the electrode body and the electrolytic solution are enclosed,
    The positive electrode uses a lithium-containing composite oxide containing lithium and a transition metal as a positive electrode active material,
    At least a part of the lithium-containing composite oxide contains nickel as a transition metal,
    The negative electrode includes, as a negative electrode active material, a material containing Si and O as constituent elements (however, an atomic ratio x of O to Si is 0.5 ≦ x ≦ 1.5) and a graphitic carbon material,
    The electrolytic solution contains a phosphonoacetate compound,
    A sealed battery, wherein a side surface of the battery case is formed with a recess recessed toward the inside of the battery case.
  2. 　請求項１に記載の密閉型電池において、
    　前記ホスホノアセテート類化合物は、下記一般式（１）のＲ３に３重結合を有する化合物である、密閉型電池。
    Figure JPOXMLDOC01-appb-C000001
     （上記一般式（１）中、Ｒ１～Ｒ３は、それぞれ独立して、ハロゲン原子で置換されていてもよい、炭素数１～１２のアルキル基、アルケニル基またはアルキニル基を示す。ｎは、０～６の整数を示す。）     The sealed battery according to claim 1,
    The phosphonoacetate compound is a sealed battery, which is a compound having a triple bond in R 3 of the following general formula (1).
    Figure JPOXMLDOC01-appb-C000001
     (In the general formula (1), R 1 to R 3 each independently represents an alkyl group, alkenyl group or alkynyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom. , Represents an integer of 0 to 6.)
  3. 　請求項２に記載の密閉型電池において、
    　前記ホスホノアセテート類化合物は、前記一般式（１）のＲ３がプロピニル基である化合物である、密閉型電池。     The sealed battery according to claim 2,
    The phosphonoacetate compound is a sealed battery in which R 3 in the general formula (1) is a propynyl group.
  4. 　請求項３に記載の密閉型電池において、
    　前記ホスホノアセテート類化合物は、２－プロピニル２－（ジエトキシホスホリル）アセテートである、密閉型電池。     The sealed battery according to claim 3,
    The sealed battery, wherein the phosphonoacetate compound is 2-propynyl 2- (diethoxyphosphoryl) acetate.
  5. 　請求項１から４のいずれか一つに記載の密閉型電池において、
    　前記正極及び前記負極の少なくとも一方は、主面上及び／または前記主面の対向面上に多孔性絶縁層が形成されている、密閉型電池。     The sealed battery according to any one of claims 1 to 4,
    At least one of the positive electrode and the negative electrode is a sealed battery in which a porous insulating layer is formed on a main surface and / or on a surface opposite to the main surface.
  6. 　請求項１から５のいずれか一つに記載の密閉型電池において、
    　前記電池ケースの側面は、少なくとも一つの角部分を有し、
    　前記凹部は、前記電池ケースの側面の角部分から前記電池ケースの側面の中央部分へと延びる直線上に配置されている、密閉型電池。     The sealed battery according to any one of claims 1 to 5,
    The side surface of the battery case has at least one corner portion,
    The said recessed part is a sealed battery arrange | positioned on the straight line extended from the corner | angular part of the side surface of the said battery case to the center part of the side surface of the said battery case.
  7. 　請求項６に記載の密閉型電池において、
    　前記電池ケースの側面は、矩形状に形成されており、
    　前記凹部は、前記電池ケースの側面の四つの角部分のうち少なくとも一つに配置されている、密閉型電池。     The sealed battery according to claim 6, wherein
    The side surface of the battery case is formed in a rectangular shape,
    The recessed portion is a sealed battery disposed in at least one of four corners on the side surface of the battery case.
  8. 　請求項６または７に記載の密閉型電池において、
    　前記電池ケースは、少なくとも一対の対向する側面を有し、
    　前記凹部は、前記電池ケースの一対の側面それぞれに形成されている、密閉型電池。     The sealed battery according to claim 6 or 7,
    The battery case has at least a pair of opposing side surfaces,
    The recessed portion is a sealed battery formed in each of a pair of side surfaces of the battery case.
  9. 　請求項６から８のいずれか一つに記載の密閉型電池において、
    　前記凹部は、前記電池ケースの側面の法線方向から見て、多角形状に形成されている、密閉型電池。     The sealed battery according to any one of claims 6 to 8,
    The said recessed part is a sealed battery formed in polygonal shape seeing from the normal line direction of the side surface of the said battery case.
  10. 　請求項９に記載の密閉型電池において、
    　前記凹部の角部分は、前記電池ケースの側面の角部分から前記電池ケースの側面の中央部分へと延びる直線上に位置している、密閉型電池。     The sealed battery according to claim 9, wherein
    The corner part of the said recessed part is a sealed battery which is located on the straight line extended from the corner part of the side surface of the said battery case to the center part of the side surface of the said battery case.
  11. 　側面に凹部を有する、有底筒状の外装缶を準備するステップと、
    　リチウム含有複合酸化物を含有する正極活物質層を正極集電体上に形成し、正極を作製するステップと、
    　Ｓｉ及びＯを構成元素に含む材料（ただし、Ｓｉに対するＯの原子比ｘは、０．５≦ｘ≦１．５）と黒鉛質炭素材料とを含有する負極活物質層を負極集電体上に形成し、負極を作製するステップと、
    　前記正極及び前記負極を有する電極体を作製するステップと、
    　前記電極体を前記外装缶内に挿入するステップと、
    　ホスホノアセテート類化合物を含有する電解液を前記外装缶内に注入するステップと、
    　前記電極体及び前記電解液を収納した外装缶を密閉するステップと、
    を備え、
    　前記リチウム含有複合酸化物は、遷移金属としてニッケルを含む、密閉型電池の製造方法。     Preparing a bottomed cylindrical outer can having a recess on a side surface;
    Forming a positive electrode active material layer containing a lithium-containing composite oxide on a positive electrode current collector, and producing a positive electrode;
    A negative electrode active material layer containing a material containing Si and O as constituent elements (provided that the atomic ratio x of O to Si is 0.5 ≦ x ≦ 1.5) and a graphitic carbon material is formed on the negative electrode current collector. Forming a negative electrode, and
    Producing an electrode body having the positive electrode and the negative electrode;
    Inserting the electrode body into the outer can;
    Injecting an electrolyte containing a phosphonoacetate compound into the outer can;
    Sealing the outer can containing the electrode body and the electrolyte; and
    With
    The method for producing a sealed battery, wherein the lithium-containing composite oxide contains nickel as a transition metal.
  12. 　請求項１１に記載の密閉型電池の製造方法において、
    　前記ホスホノアセテート類化合物は、下記一般式（１）のＲ３に３重結合を有する化合物である、製造方法。
    Figure JPOXMLDOC01-appb-C000002
     （上記一般式（１）中、Ｒ１～Ｒ３は、それぞれ独立して、ハロゲン原子で置換されていてもよい、炭素数１～１２のアルキル基、アルケニル基またはアルキニル基を示す。ｎは、０～６の整数を示す。）     In the manufacturing method of the sealed battery according to claim 11,
    The phosphonoacetate compound is a compound having a triple bond in R 3 of the following general formula (1), the production method.
    Figure JPOXMLDOC01-appb-C000002
     (In the general formula (1), R 1 to R 3 each independently represents an alkyl group, alkenyl group or alkynyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom. , Represents an integer of 0 to 6.)
  13. 　請求項１２に記載の密閉型電池の製造方法において、
    　前記ホスホノアセテート類化合物は、前記一般式（１）のＲ３がプロピニル基である化合物である、製造方法。     In the manufacturing method of the sealed battery according to claim 12,
    The said phosphono acetate compound is a manufacturing method whose R < 3 > of the said General formula (1) is a propynyl group.
  14. 　請求項１３に記載の密閉型電池の製造方法において、
    　前記ホスホノアセテート類化合物は、２－プロピニル２－（ジエトキシホスホリル）アセテートである、製造方法。     In the manufacturing method of the sealed battery according to claim 13,
    The production method, wherein the phosphonoacetate compound is 2-propynyl 2- (diethoxyphosphoryl) acetate.
  15. 　請求項１１から１４のいずれか一つに記載の密閉型電池の製造方法において、
    　前記正極及び前記負極の少なくとも一方の主面上及び／または前記主面の対向面上に、多孔性絶縁層を形成するステップ、をさらに備える、製造方法。     In the manufacturing method of the sealed type battery according to any one of claims 11 to 14,
    Forming a porous insulating layer on at least one main surface of the positive electrode and the negative electrode and / or on a surface opposite to the main surface.
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