WO2021029126A1 - Battery - Google Patents

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Publication number
WO2021029126A1
WO2021029126A1 PCT/JP2020/022353 JP2020022353W WO2021029126A1 WO 2021029126 A1 WO2021029126 A1 WO 2021029126A1 JP 2020022353 W JP2020022353 W JP 2020022353W WO 2021029126 A1 WO2021029126 A1 WO 2021029126A1
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Prior art keywords
negative electrode
positive electrode
active material
battery
current collector
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PCT/JP2020/022353
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French (fr)
Japanese (ja)
Inventor
中村　利一
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株式会社村田製作所
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Publication of WO2021029126A1 publication Critical patent/WO2021029126A1/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
    • H01M10/04—Construction or manufacture in general
    • 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
    • H01M10/058—Construction or manufacture
    • H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
    • 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
    • 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 battery.
  • Patent Document 1 in a winding type battery, a resin film is provided at the ends of the positive electrode and the negative electrode on the winding core side for the purpose of protecting the innermost diameter on the winding core side and the portion easily distorted due to deformation such as a step.
  • the technique of placement is disclosed.
  • buckling means a local bending in a region of several mm from the electrode cutting end (for example, the positive electrode cutting end) on the winding center side, and the occurrence of “buckling” refers to the separator. It may break through and cause a physical short circuit (short circuit) with the counter electrode (for example, the negative electrode).
  • An object of the present invention is to provide a battery capable of suppressing buckling of an electrode on the winding center side.
  • a wound electrode body including a positive electrode and a negative electrode is provided.
  • the negative electrode is A negative electrode current collector having a first surface and a second surface, A negative electrode active material layer provided on the first surface and the second surface so that the first surface is exposed at the winding center side end of the electrode body. It is provided with a metal layer provided on the exposed first surface at the winding center side end.
  • the metal layer is a battery that is wound in a tubular shape.
  • the second invention is A wound electrode body including a positive electrode and a negative electrode is provided.
  • the electrode located on the innermost circumference of the electrode body is A current collector having a first surface and a second surface, An active material layer provided on the first surface and the second surface so that the first surface is exposed at the end of the electrode body on the winding center side. It is provided with a metal layer provided on the exposed first surface at the end on the winding center side.
  • the metal layer is a battery that is wound in a tubular shape.
  • This battery is, for example, a so-called lithium ion secondary battery in which the capacity of the negative electrode is represented by a capacity component due to occlusion and release of lithium (Li), which is an electrode reactant.
  • This battery is a so-called cylindrical type, and a pair of strip-shaped positive electrodes 21 and strip-shaped negative electrodes 22 are laminated and wound inside a substantially hollow cylindrical battery can 11 via a separator 23.
  • a mold electrode body 20 (hereinafter, simply referred to as “electrode body 20”) is provided.
  • the battery can 11 is made of iron (Fe) plated with nickel (Ni), and one end thereof is closed and the other end is open.
  • An electrolytic solution as a liquid electrolyte is injected into the inside of the battery can 11, and the positive electrode 21, the negative electrode 22, and the separator 23 are impregnated.
  • a pair of insulating plates 12 and 13 are arranged perpendicular to the winding peripheral surface so as to sandwich the electrode body 20.
  • a battery lid 14 At the open end of the battery can 11, a battery lid 14, a safety valve mechanism 15 provided inside the battery lid 14, and a heat-sensitive resistance element (Positive Temperature Coefficient; PTC element) 16 are interposed via a sealing gasket 17. It is attached by being crimped. As a result, the inside of the battery can 11 is sealed.
  • the battery lid 14 is made of, for example, the same material as the battery can 11.
  • the safety valve mechanism 15 is electrically connected to the battery lid 14, and when the internal pressure of the battery exceeds a certain level due to an internal short circuit or heating from the outside, the disk plate 15A is inverted and the battery lid 14 and the electrode It is designed to disconnect the electrical connection with the body 20.
  • the sealing gasket 17 is made of, for example, an insulating material, and the surface is coated with asphalt.
  • the electrode body 20 has a substantially columnar shape.
  • the electrode body 20 has a center hole 20A penetrating from the center of the first end face toward the center of the second end face.
  • the central hole 20A functions as a flow path for guiding the gas from the can bottom side of the battery can 11 to the battery lid 14 side opposite to the gas when gas is generated in the battery can 11.
  • a positive electrode tab 25 made of aluminum (Al) or the like is connected to the positive electrode 21, and a negative electrode tab 26 and a negative electrode tab 27 made of nickel or the like are connected to the negative electrode 22.
  • the positive electrode tab 25 is electrically connected to the battery lid 14 by being welded to the safety valve mechanism 15, and the negative electrode tab 26 and the negative electrode tab 27 are welded to the battery can 11 and electrically connected.
  • the positive electrode 21, the negative electrode 22, the separator 23, and the electrolytic solution constituting the battery will be sequentially described with reference to FIGS. 2 to 4.
  • 2 and 3 show an example in which the negative electrode 22 of the positive electrode 21 and the negative electrode 22 is an electrode located on the innermost circumference of the electrode body 20, but the positive electrode 21 is the innermost circumference of the electrode body 20. It may be an electrode located at.
  • the positive electrode 21 includes a positive electrode current collector 21A having an inner side surface (third surface) 21S1 and an outer surface (fourth surface) 21S2, and a positive electrode active material layer 21B1 provided on the inner side surface 21S1 of the positive electrode current collector 21A. And the positive electrode active material layer 21B2 provided on the outer surface 21S2 of the positive electrode current collector 21A.
  • the "inner surface” means a surface located on the winding center side
  • the "outer surface” means a surface located on the side opposite to the winding center.
  • the tips of the positive electrode active material layer 21B1 and the positive electrode current collector 21A are aligned, and the tips of the positive electrode active material layer 21B2 and the positive electrode current collector 21A are aligned.
  • the inner side surface 21S1 of the end portion of the positive electrode current collector 21A on the winding center side is covered with the positive electrode active material layer 21B1 so that the inner side surface 21S1 is not exposed.
  • the outer surface 21S2 at the end of the positive electrode current collector 21A on the winding center side is covered with the positive electrode active material layer 21B2 so that the outer surface 21S2 is not exposed.
  • the resistance of the positive electrode active material layer 21B1 and the positive electrode active material layer 21B2 is one digit or more lower than the resistance of the positive electrode current collector 21A. Therefore, when the positive electrode active material layer 21B1 and the positive electrode active material layer 21B2 are covered at the end of the positive electrode current collector 21A on the winding center side as described above, the winding center side of the positive electrode current collector 21A Compared with the case where the end portion of the positive electrode active material layer 21B1 and the positive electrode active material layer 21B2 is not covered (that is, the end portion on the winding center side of the positive electrode current collector 21A is exposed), the positive electrode 21 The risk of short-circuiting the negative electrode 22 can be reduced.
  • the tips of the positive electrode active material layer 21B1 and the positive electrode current collector 21A are aligned, and the tips of the positive electrode active material layer 21B2 and the positive electrode current collector 21A are aligned.
  • the inner side surface 21S1 of the winding outer peripheral side end of the positive electrode 21 is covered with the positive electrode active material layer 21B1 so that the inner side surface 21S1 is not exposed.
  • the outer surface 21S2 of the winding outer peripheral end of the positive electrode 21 is covered with the positive electrode active material layer 21B2 so that the outer surface 21S2 is not exposed.
  • the winding outer peripheral end of the positive electrode current collector 21A When the positive electrode active material layer 21B1 and the positive electrode active material layer 21B2 are covered by the winding outer peripheral end of the positive electrode current collector 21A as described above, the winding outer peripheral end of the positive electrode current collector 21A The positive electrode 21 and the negative electrode 22 are compared with the case where the portion is not covered by the positive electrode active material layer 21B1 and the positive electrode active material layer 21B2 (that is, the end portion on the winding outer peripheral side of the positive electrode current collector 21A is exposed). Can reduce the risk of short circuit.
  • the positive electrode active material layer 21B1 and the positive electrode active material layer 21B2 are not provided on the inner side surface 21S1 and the outer side surface 21S2 of the middle peripheral portion of the positive electrode 21, and the inner side surface 21S1 and the positive electrode current collector 21A
  • a positive electrode current collector exposed portion 21C1 and a positive electrode current collector exposed portion 21C2 with the outer side surface 21S2 exposed are provided.
  • the middle peripheral portion of the positive electrode 21 means a portion between the end portion on the winding center side and the end portion on the winding outer peripheral side.
  • the positive electrode current collector exposed portion 21C1 or the positive electrode current collector exposed portion 21C2 is provided with a positive electrode tab 25.
  • FIG. 2 shows an example in which the positive electrode tab 25 is provided on the positive electrode current collector exposed portion 21C1.
  • the positive electrode tab 25 may be covered with insulating tape (not shown).
  • the positive electrode current collector 21A is made of, for example, a metal foil such as an aluminum foil, a nickel foil, or a stainless steel foil.
  • the positive electrode active material layer 21B1 and the positive electrode active material layer 21B2 contain a positive electrode active material capable of occluding and releasing lithium.
  • the positive electrode active material layer 21B1 and the positive electrode active material layer 21B2 may further contain at least one of a binder and a conductive agent, if necessary.
  • a lithium-containing compound such as a lithium oxide, a lithium phosphorus oxide, a lithium sulfide or an interlayer compound containing lithium is suitable, and these two types are suitable. The above may be mixed and used.
  • a lithium-containing compound containing lithium, a transition metal element, and oxygen (O) is preferable.
  • Examples of such a lithium-containing compound include a lithium composite oxide having a layered rock salt type structure represented by the formula (A), a lithium composite phosphate having an olivine type structure represented by the formula (B), and the like. Can be mentioned.
  • the lithium-containing compound is more preferably one containing at least one of the group consisting of cobalt (Co), nickel (Ni), manganese (Mn) and iron (Fe) as a transition metal element.
  • Examples of such a lithium-containing compound include a lithium composite oxide having a layered rock salt type structure represented by the formula (C), the formula (D) or the formula (E), and a spinel type represented by the formula (F).
  • Examples thereof include a lithium composite oxide having a structure and a lithium composite phosphate having an olivine-type structure represented by the formula (G).
  • M1 represents at least one of the elements selected from groups 2 to 15 excluding nickel and manganese.
  • X is at least one of the group 16 and group 17 elements other than oxygen.
  • P, q, y, z are 0 ⁇ p ⁇ 1.5, 0 ⁇ q ⁇ 1.0, 0 ⁇ r ⁇ 1.0, ⁇ 0.10 ⁇ y ⁇ 0.20, 0 ⁇ It is a value within the range of z ⁇ 0.2.
  • M2 represents at least one of the elements selected from groups 2 to 15.
  • a and b are 0 ⁇ a ⁇ 2.0 and 0.5 ⁇ b ⁇ 2.0. It is a value within the range of.
  • M3 is cobalt, magnesium (Mg), aluminum, boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron, copper, zinc (Zn), Represents at least one of the group consisting of zirconium (Zr), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr) and tungsten (W).
  • Zr zirconium
  • Mo molybdenum
  • Sn tin
  • Ca calcium
  • W tungsten
  • composition of lithium differs depending on the state of charge and discharge, and the value of f represents the value in the state of complete discharge.
  • M4 is at least in the group consisting of cobalt, manganese, magnesium, aluminum, boron, titanium, vanadium, chromium, iron, copper, zinc, molybdenum, tin, calcium, strontium and tungsten.
  • M, n, p and q are 0.8 ⁇ m ⁇ 1.2, 0.005 ⁇ n ⁇ 0.5, ⁇ 0.1 ⁇ p ⁇ 0.2, 0 ⁇ q ⁇ 0. It is a value within the range of .1.
  • the composition of lithium differs depending on the state of charge and discharge, and the value of m represents the value in the state of complete discharge.
  • M5 is at least in the group consisting of nickel, manganese, magnesium, aluminum, boron, titanium, vanadium, chromium, iron, copper, zinc, molybdenum, tin, calcium, strontium and tungsten.
  • R, s, t and u are 0.8 ⁇ r ⁇ 1.2, 0 ⁇ s ⁇ 0.5, ⁇ 0.1 ⁇ t ⁇ 0.2, 0 ⁇ u ⁇ 0.1.
  • the composition of lithium differs depending on the state of charge and discharge, and the value of r represents the value in the state of complete discharge.
  • M6 is at least in the group consisting of cobalt, nickel, magnesium, aluminum, boron, titanium, vanadium, chromium, iron, copper, zinc, molybdenum, tin, calcium, strontium and tungsten.
  • V, w, x and y are 0.9 ⁇ v ⁇ 1.1, 0 ⁇ w ⁇ 0.6, 3.7 ⁇ x ⁇ 4.1, 0 ⁇ y ⁇ 0.1. It is a value within the range.
  • the composition of lithium differs depending on the state of charge and discharge, and the value of v represents the value in the state of complete discharge.
  • M7 is composed of cobalt, manganese, iron, nickel, magnesium, aluminum, boron, titanium, vanadium, niobium (Nb), copper, zinc, molybdenum, calcium, strontium, tungsten and zirconium. Represents at least one of the groups.
  • Z is a value within the range of 0.9 ⁇ z ⁇ 1.1.
  • the composition of lithium differs depending on the state of charge and discharge, and the value of z is the state of complete discharge. Represents the value in.
  • lithium composite oxide containing nickel examples include a lithium composite oxide containing lithium, nickel, cobalt, manganese and oxygen (NCM), and a lithium composite oxide containing lithium, nickel, cobalt, aluminum and oxygen (NCA). May be used.
  • the lithium composite oxide containing nickel those represented by the following formula (H) or formula (I) may be used.
  • Li v1 Ni w1 M1 'x1 O z1 ⁇ (H) (In the formula, 0 ⁇ v1 ⁇ 2, w1 + x1 ⁇ 1, 0.2 ⁇ w1 ⁇ 1, 0 ⁇ x1 ⁇ 0.7, 0 ⁇ z ⁇ 3, and M1 ′ is cobalt, iron, manganese, copper, At least one element composed of transition metals such as zinc, aluminum, chromium, vanadium, titanium, magnesium and zirconium.)
  • Li v2 Ni w2 M2 'x2 O z2 ⁇ (I) (In the formula, 0 ⁇ v2 ⁇ 2, w2 + x2 ⁇ 1, 0.65 ⁇ w2 ⁇ 1, 0 ⁇ x2 ⁇ 0.35, 0 ⁇ z2 ⁇ 3, and M2'is cobalt, iron, manganese, copper, At least one element composed of transition metals such as zinc, aluminum, chromium, vanadium, titanium, magnesium and zirconium.)
  • positive electrode active materials capable of occluding and releasing lithium include lithium-free inorganic compounds such as MnO 2 , V 2 O 5 , V 6 O 13 , NiS, and MoS.
  • the positive electrode active material capable of occluding and releasing lithium may be other than the above.
  • two or more kinds of positive electrode active materials exemplified above may be mixed in any combination.
  • the binder is, for example, at least one selected from the group consisting of polyvinylidene fluoride, polytetrafluoroethylene, polyacrylonitrile, styrene butadiene rubber, carboxymethyl cellulose, and a copolymer mainly composed of one of these resin materials. Seeds can be used.
  • the conductive agent for example, at least one carbon material selected from the group consisting of graphite, carbon fiber, carbon black, acetylene black, ketjen black, carbon nanotubes, graphene and the like can be used.
  • the conductive agent may be any material having conductivity, and is not limited to the carbon material.
  • a metal material, a conductive polymer material, or the like may be used as the conductive agent.
  • the shape of the conductive agent includes, for example, granular, scaly, hollow, needle-shaped, tubular, and the like, but is not particularly limited to these shapes.
  • the negative electrode 22 includes a negative electrode current collector 22A having an inner side surface (first surface) 22S1 and an outer side surface (second surface) 22S2, and a negative electrode active material layer 22B1 provided on the inner side surface 22S1 of the negative electrode current collector 22A. And the negative electrode active material layer 22B2 provided on the outer surface 22S2 of the negative electrode current collector 22A.
  • the negative electrode active material layer 22B1 is not provided on the inner side surface 22S1 of the central end portion of the negative electrode 22, and the negative electrode current collector exposed portion 22C1 in which the inner side surface 22S1 of the negative electrode current collector 22A is exposed is provided.
  • the negative electrode active material layer 22B2 is not provided on the outer surface 22S2 of the central end portion of the negative electrode 22, and the negative electrode current collector exposed portion 22C2 in which the outer surface 22S2 of the negative electrode current collector 22A is exposed is provided.
  • a reinforcing metal layer 24 is provided on the negative electrode current collector exposed portion 22C1, and a negative electrode tab 27 is provided on the reinforcing metal layer 24.
  • the reinforcing metal layer 24 and the negative electrode tab 27 are welded to the negative electrode current collector 22A once. Can be attached. Further, since the negative electrode tab 27 is wrapped in the reinforcing metal layer 24, it is possible to suppress the occurrence of a physical short circuit due to cut burrs or the like of the negative electrode tab 27.
  • the reinforcing metal layer 24 reinforces the central hole 20A. Specifically, the reinforcing metal layer 24 retains the shape and size of the central hole 20A of the electrode body 20 when the electrode body 20 is expanded and contracted by charging and discharging the battery.
  • the reinforcing metal layer 24 has, for example, a foil shape or a plate shape.
  • the reinforcing metal layer 24 is wound in a cylindrical shape together with the negative electrode current collector exposed portion 22C1.
  • the problem of the electrode body 30 in which the reinforcing metal layer 24 is not provided will be described with reference to FIG.
  • the electrode body 30 expands and contracts due to charging and discharging of the battery and pressure is generated toward the central hole 20A of the electrode body 30, the shape and size of the central hole 20A of the electrode body 30 changes.
  • the negative electrode 22 located inside the tip of the positive electrode 21 on the winding center side is pushed by the tip 21D of the positive electrode 21 on the winding center side, and buckling occurs in the negative electrode 22 (in FIG. 5). , See region 20R).
  • the separator 23 may be damaged and the positive electrode 21 and the negative electrode 22 may be short-circuited.
  • the reliability and safety of the battery are lowered.
  • the electrode body 20 has a cylindrical reinforcing metal layer 24 wound around the end of the negative electrode 22 on the winding center side together with the negative electrode current collector exposed portion 22C1. Therefore, the strength of the central hole 20A of the electrode body 20 can be improved. As a result, when the electrode body 20 expands and contracts due to charging and discharging of the battery and pressure is generated toward the central hole 20A of the electrode body 20, the shape and size of the central hole 20A of the electrode body 20 are suppressed from changing. can do.
  • the outer surface of the negative electrode 22 is pressed against the tip 21D on the winding center side of the positive electrode 21, and buckling can be suppressed from occurring in the negative electrode 22 (see region 20R in FIG. 2). Therefore, a short circuit between the positive electrode 21 and the negative electrode 22 can be suppressed. Therefore, it is possible to suppress a decrease in the reliability and safety of the battery.
  • the reinforcing metal layer 24 preferably contains copper, copper-nickel alloy, nickel, zinc, copper-zinc alloy or copper-zinc-nickel alloy.
  • the reinforcing metal layer 24 contains such a material, it is possible to prevent the reinforcing metal layer 24 connected to the negative electrode current collector 22A from being melted during charging and discharging. Therefore, it is possible to suppress a decrease in the reliability of the battery.
  • the thickness of the reinforcing metal layer 24 is preferably 20 ⁇ m or more and 100 ⁇ m or less, and more preferably 30 ⁇ m or more and 80 ⁇ m or less.
  • the thickness of the reinforcing metal layer 24 is 20 ⁇ m or more, the strength of the reinforcing metal layer 24 wound in a cylindrical shape can be sufficiently increased, so that when the electrode body 20 is expanded and contracted by charging and discharging the battery.
  • the thickness of the reinforcing metal layer 24 is 100 ⁇ m or less, it is possible to suppress an increase in the step at the end of the reinforcing metal layer 24 on the winding outer peripheral side, so that the step shape is larger than that of the reinforcing metal layer 24. It is possible to suppress the transfer to the positive electrode 21 and the negative electrode 22 located on the outer peripheral side. Therefore, it is possible to suppress the occurrence of distortion in the positive electrode 21 and the negative electrode 22, and thus it is possible to suppress a decrease in the reliability of the battery. Further, when the thickness of the reinforcing metal layer 24 is 100 ⁇ m or less, the decrease in the number of turns of the positive electrode 21 and the negative electrode 22 can be suppressed, so that the decrease in the energy density of the battery can be suppressed.
  • the number of turns of the reinforcing metal layer 24 is at least 1 lap or more, preferably 1.2 laps or more and 3 laps or less, and more preferably 1.2 laps or more and 1.8 laps or less. If the number of turns is less than one, the reinforcing metal layer 24 cannot be wound in a cylindrical shape, so that the effect of suppressing buckling of the negative electrode 22 is significantly reduced. When the number of turns is 1.2 or more, the strength of the reinforcing metal layer 24 wound in a cylindrical shape can be sufficiently increased, so that the electrode body 20 expands and contracts due to charging and discharging of the battery, and the electrode body 20 expands and contracts.
  • the negative electrode active material layer 22B1 is not provided on the inner side surface 22S1 of the end on the winding outer peripheral side of the negative electrode 22, and the negative electrode current collector exposed portion 22D1 in which the inner side surface 22S1 of the negative electrode current collector 22A is exposed is provided. There is.
  • the negative electrode active material layer 22B2 is not provided on the outer surface 22S2 of the end on the winding outer peripheral side of the negative electrode 22, and the negative electrode current collector exposed portion 22D2 in which the outer surface 22S2 of the negative electrode current collector 22A is exposed is provided.
  • the negative electrode current collector exposed portion 22D1 or the negative electrode current collector exposed portion 22D2 is provided with a negative electrode tab 26.
  • FIGS. 2 and 3 show an example in which the negative electrode tab 26 is provided on the negative electrode current collector exposed portion 22D1.
  • the negative electrode current collector 22A is made of, for example, a metal foil such as a copper foil, a nickel foil, or a stainless steel foil.
  • the negative electrode active material layer 22B1 and the negative electrode active material layer 22B2 contain a negative electrode active material capable of storing and releasing lithium.
  • the negative electrode active material layer 22B1 and the negative electrode active material layer 22B2 may further contain at least one of a binder and a conductive agent, if necessary.
  • the electrochemical equivalent of the negative electrode 22 or the negative electrode active material is larger than the electrochemical equivalent of the positive electrode 21, and theoretically, lithium metal does not precipitate on the negative electrode 22 during charging. It is preferable to have.
  • the negative electrode active material includes, for example, a first negative electrode active material containing a carbon-containing material.
  • the negative electrode active material preferably further contains a second negative electrode active material containing a silicon (Si) -containing material.
  • the content of the second negative electrode active material in the negative electrode active material layer 22B1 and the content of the second negative electrode active material in the negative electrode active material layer 22B2 are preferably 5% by mass or more and 20% by mass or less, more preferably 10. It is 0% by mass or more and 20% by mass or less.
  • the content of the second negative electrode active material is 5% by mass or more and 20% by mass or less, a high theoretical capacity can be obtained, and buckling occurs in the negative electrode 22 on the winding center side of the electrode body 20. Can be done.
  • the content of the above-mentioned second negative electrode active material is determined as follows. First, the negative electrode 22 is taken out from the battery, washed with dimethyl carbonate (DMC) and dried, and then the negative electrode current collector 22A is removed. Next, a sample of several to several tens of mg (negative electrode active material layer 22B1 and negative electrode active material layer 22B2) was used with a differential heat balance device (TG-DTA, for example, Rigaku Thermo plus TG8120 manufactured by Rigaku Co., Ltd.) at 1 to 5 ° C./
  • TG-DTA differential heat balance device
  • the second negative electrode activity contained in the negative electrode active material layer 22B1 and the negative electrode active material layer 22B2 is determined by the amount of weight loss at that time when heating is performed in an air atmosphere (for example, heating to 600 ° C.) at a heating rate of min.
  • the mass of a material other than the substance is determined.
  • the "mass of the material other than the second positive electrode active material” is subtracted from the "total mass of the negative electrode active material layer 22B1 and the negative electrode active material layer 22B2" to obtain the "mass of the second negative electrode active material”.
  • the ratio of the "mass of the second negative electrode active material” to the "total mass of the negative electrode active material layer 22B1 and the negative electrode active material layer 22B2" is determined as a percentage (mass%).
  • the first negative electrode active material contains a carbon-containing material as described above.
  • the carbon-containing material means a general term for materials containing carbon as a constituent element.
  • the carbon-containing material may contain only carbon as a constituent element.
  • the type of carbon-containing material may be only one type or two or more types.
  • the first negative electrode active material contains a carbon-containing material
  • the crystal structure of the carbon-containing material hardly changes at the time of occlusion and release of lithium, and the carbon-containing material also functions as a conductive agent.
  • a high energy density can be stably obtained, and the conductivity of the negative electrode active material layer 22B1 and the negative electrode active material layer 22B2 can be improved.
  • the carbon-containing material is, for example, graphitizable carbon, non-graphitizable carbon, graphite, and the like.
  • the interplanar spacing of the (002) plane in graphitizable carbon is, for example, 0.37 nm or more
  • the interplanar spacing of the (002) plane in graphite is, for example, 0.34 nm or less.
  • the carbon-containing material is, for example, pyrolytic carbons, cokes, glassy carbon fibers, calcined organic polymer compound, activated carbon, carbon blacks, and the like.
  • cokes include, for example, pitch coke, needle coke, petroleum coke and the like.
  • the fired organic polymer compound is a fired product obtained by firing (carbonizing) a polymer compound such as a phenol resin and a furan resin at an arbitrary temperature.
  • the carbon-containing material may be, for example, low crystalline carbon heat-treated at a temperature of about 1000 ° C. or lower, or amorphous carbon.
  • the shape of the first negative electrode active material is not particularly limited, but is, for example, fibrous, spherical (particulate), scaly, or the like. A plurality of first negative electrode active materials having two or more types of shapes may be mixed.
  • the second negative electrode active material contains a silicon-containing material as described above.
  • the silicon-containing material means a general term for materials containing silicon as a constituent element.
  • the silicon-containing material may contain only silicon as a constituent element.
  • the type of silicon-containing material may be only one type or two or more types.
  • the Kay-containing material can form an alloy with lithium, and may be a simple substance of silicon, an alloy of silicon, a compound of silicon, a mixture of two or more of them, or one of them. Alternatively, a material containing two or more kinds of phases may be used. Further, the silicon-containing material may be crystalline, amorphous, or may contain both a crystalline portion and an amorphous portion. However, since the simple substance described here means a general simple substance to the last, it may contain a trace amount of impurities. That is, the purity of a simple substance is not necessarily limited to 100%.
  • Silicon alloys include, for example, tin, nickel, copper, iron, cobalt, manganese, zinc, indium (In), silver (Ag), titanium, germanium (Ge), bismuth (Bi), as constituent elements other than silicon. Includes any one or more of antimony (Sb), chromium and the like.
  • the silicon compound contains, for example, any one or more of carbon, oxygen, and the like as constituent elements other than silicon.
  • the silicon compound may contain, for example, any one or more of the series of constituent elements described for the silicon alloy as constituent elements other than silicon.
  • the silicon alloy and the silicon compound are, for example, SiB 4 , SiB 6 , Mg 2 Si, Ni 2 Si, TiSi 2 , MoSi 2 , CoSi 2 , NiSi 2 , CaSi 2 , CrSi 2 , Cu 5 Si, FeSi 2 , MnSi 2 , NbSi 2 , TaSi 2 , VSi 2 , WSi 2 , ZnSi 2 , SiC, Si 3 N 4 , Si 2 N 2 O, SiO v (0 ⁇ v ⁇ 2) and the like.
  • the range of v can be arbitrarily set, and may be, for example, 0.2 ⁇ v ⁇ 1.4.
  • the negative electrode active material may be, for example, any one of the other negative electrode active materials together with the above-mentioned first negative electrode active material, or with the above-mentioned first negative electrode active material and the second negative electrode active material. Two or more types may be included.
  • the other negative electrode active material is, for example, a metal-based material
  • the metal-based material is a general term for materials containing any one or more of metal elements and metalloid elements as constituent elements. High energy density can be obtained by including the metal material in the other negative electrode active material.
  • the metal-based material may be a simple substance, an alloy, a compound, a mixture of two or more kinds thereof, or a material containing one kind or two or more kinds of phases thereof.
  • the alloy includes not only a material composed of two or more kinds of metal elements, but also a material containing one kind or two or more kinds of metal elements and one kind or two or more kinds of metalloid elements. Further, the alloy may contain one kind or two or more kinds of non-metal elements.
  • the structure of the metal-based material is, for example, a solid solution, a eutectic (eutectic mixture), an intermetallic compound, and a coexistence of two or more of them.
  • Each of the metallic element and the metalloid element can form an alloy with lithium.
  • the metal elements and metalloid elements are, for example, magnesium, boron, aluminum, gallium, indium, germanium, tin, lead, bismuth, cadmium, silver, zinc, hafnium, zirconium, yttrium, palladium, platinum and the like. is there.
  • binder As the binder, the same binder as that of the positive electrode active material layer 21B can be used.
  • Conducting agent As the conductive agent, the same one as that of the positive electrode active material layer 21B can be used.
  • the separator 23 separates the positive electrode 21 and the negative electrode 22 and allows lithium ions to pass through while preventing a short circuit of current due to contact between the two electrodes.
  • the separator 23 is porous, for example, made of polytetrafluoroethylene, polyolefin resin (polypropylene (PP), polyethylene (PE), etc.), acrylic resin, styrene resin, polyester resin or nylon resin, or a resin blended with these resins. It is composed of a quality film, and may have a structure in which two or more of these porous films are laminated.
  • the porous film made of polyolefin is preferable because it has an excellent short-circuit prevention effect and can improve the safety of the battery by the shutdown effect.
  • polyethylene is preferable as a material constituting the separator 23 because it can obtain a shutdown effect in the range of 100 ° C. or higher and 160 ° C. or lower and is also excellent in electrochemical stability.
  • low-density polyethylene, high-density polyethylene, and linear polyethylene are preferably used because they have an appropriate melting temperature and are easily available.
  • a material obtained by copolymerizing or blending a resin having chemical stability with polyethylene or polypropylene can be used.
  • the porous film may have a structure of three or more layers in which a polypropylene layer, a polyethylene layer, and a polypropylene layer are sequentially laminated.
  • a polypropylene layer a polypropylene layer
  • a single-layer base material having 100 wt% PP or 100 wt% PE can be used.
  • the method for producing the separator 23 may be wet or dry.
  • a non-woven fabric may be used as the separator 23.
  • the fiber constituting the non-woven fabric aramid fiber, glass fiber, polyolefin fiber, polyethylene terephthalate (PET) fiber, nylon fiber and the like can be used. Further, these two or more kinds of fibers may be mixed to form a non-woven fabric.
  • the separator 23 may have a structure including a base material and a surface layer provided on one side or both sides of the base material.
  • the surface layer contains inorganic particles having an electrically insulating property, and a resin material that binds the inorganic particles to the surface of the base material and also binds the inorganic particles to each other.
  • This resin material may have, for example, a three-dimensional network structure in which fibrils are formed and a plurality of fibrils are connected. The inorganic particles are supported on a resin material having this three-dimensional network structure. Further, the resin material may bind the surface of the base material or the inorganic particles to each other without becoming fibril. In this case, higher binding properties can be obtained.
  • the base material is a porous membrane composed of an insulating membrane that allows lithium ions to permeate and has a predetermined mechanical strength. Since the electrolytic solution is held in the pores of the base material, it is resistant to the electrolytic solution. It is preferable that the properties are high, the reactivity is low, and the swelling is difficult.
  • the resin material or the non-woven fabric constituting the separator 23 described above can be used as the material constituting the base material.
  • Inorganic particles include at least one such as metal oxides, metal nitrides, metal carbides and metal sulfides.
  • metal oxides include aluminum oxide (alumina, Al 2 O 3 ), boehmite (hydrated aluminum oxide), magnesium oxide (magnesia, MgO), titanium oxide (titania, TiO 2 ), zirconium oxide (zirconia, ZrO 2). ), silicon oxide (silica, SiO 2) or yttrium oxide (yttria, Y 2 O 3) or the like can be suitably used.
  • silicon nitride Si 3 N 4
  • aluminum nitride AlN
  • boron nitride BN
  • titanium nitride TiN
  • the metal carbide may be used silicon carbide (SiC) or boron carbide (B 4 C) or the like suitably.
  • metal sulfide barium sulfate (BaSO 4 ) or the like can be preferably used.
  • porous aluminosilicates such as zeolite (M 2 / n O, Al 2 O 3 , xSiO 2 , yH 2 O, M is a metal element, x ⁇ 2, y ⁇ 0), layered silicate, and barium titanate.
  • Minerals such as barium (BaTIO 3 ) or strontium titanate (SrTiO 3 ) may be used.
  • alumina, titania (particularly those having a rutile type structure), silica or magnesia are preferably used, and alumina is more preferable.
  • the inorganic particles have oxidation resistance and heat resistance, and the surface layer on the side surface facing the positive electrode containing the inorganic particles has strong resistance to the oxidizing environment in the vicinity of the positive electrode during charging.
  • the shape of the inorganic particles is not particularly limited, and any of spherical, plate-like, fibrous, cubic, random and the like can be used.
  • the particle size of the inorganic particles is preferably in the range of 1 nm or more and 10 ⁇ m or less. If the particle size is less than 1 nm, it is difficult to obtain inorganic particles. On the other hand, if the particle size exceeds 10 ⁇ m, the distance between the electrodes becomes large, the amount of active material filled cannot be sufficiently obtained in a limited space, and the battery capacity decreases.
  • Examples of the resin material constituting the surface layer include fluororesins such as polyvinylidene fluoride and polytetrafluoroethylene, fluororubber containing vinylidene fluoride-tetrafluoroethylene copolymer, ethylene-tetrafluoroethylene copolymer and the like, and styrene.
  • fluororesins such as polyvinylidene fluoride and polytetrafluoroethylene
  • fluororubber containing vinylidene fluoride-tetrafluoroethylene copolymer ethylene-tetrafluoroethylene copolymer and the like
  • styrene styrene
  • Examples thereof include resins having high heat resistance of ° C. or higher. These resin materials may be used alone or in combination of two or more. Among them, a fluorine-based resin such as polyvinylidene fluoride is preferable from the viewpoint of oxidation resistance and flexibility, and aramid or polyamide-imide is preferably contained from the viewpoint of heat resistance.
  • a slurry composed of a matrix resin, a solvent and an inorganic substance is applied onto a base material (porous film), and the matrix resin is passed through a poor solvent and a parent solvent bath of the above solvent to form a phase.
  • a method of separating and then drying can be used.
  • the above-mentioned inorganic particles may be contained in a porous membrane as a base material. Further, the surface layer may not contain inorganic particles and may be composed only of a resin material.
  • the electrolytic solution is a so-called non-aqueous electrolytic solution, and contains an organic solvent (non-aqueous solvent) and an electrolyte salt dissolved in the organic solvent.
  • the electrolyte may contain known additives to improve battery characteristics.
  • an electrolyte layer containing an electrolytic solution and a polymer compound serving as a retainer for holding the electrolytic solution may be used.
  • the electrolyte layer may be in the form of a gel.
  • a cyclic carbonate ester such as ethylene carbonate or propylene carbonate can be used, and it is preferable to use one of ethylene carbonate and propylene carbonate, particularly both. This is because the cycle characteristics can be further improved.
  • organic solvent in addition to these cyclic carbonate esters, it is preferable to mix and use a chain carbonate ester such as diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate or methyl propyl carbonate. This is because high ionic conductivity can be obtained.
  • organic solvent it is preferable to further contain 2,4-difluoroanisole or vinylene carbonate. This is because 2,4-difluoroanisole can further improve the discharge capacity, and vinylene carbonate can further improve the cycle characteristics. Therefore, it is preferable to mix and use these because the discharge capacity and the cycle characteristics can be further improved.
  • organic solvents butylene carbonate, ⁇ -butyrolactone, ⁇ -valerolactone, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyl tetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3 -Dioxolane, methyl acetate, methyl propionate, acetonitrile, glutaronitrile, adiponitrile, methoxynitrile, 3-methoxypropyronitrile, N, N-dimethylformamide, N-methylpyrrolidinone, N-methyloxazolidinone, N, N- Examples thereof include dimethylimidazolidinone, nitromethane, nitroethane, sulfolane, dimethylsulfoxide, trimethyl phosphate and the like.
  • a compound in which at least a part of hydrogen in these organic solvents is replaced with fluorine may be preferable because the reversibility of the electrode reaction may be improved depending on the type of electrode to be combined.
  • Examples of the electrolyte salt include a lithium salt, and one type may be used alone, or two or more types may be mixed and used.
  • Lithium salts include LiPF 6 , LiBF 4 , LiAsF 6 , LiClO 4 , LiB (C 6 H 5 ) 4 , LiCH 3 SO 3 , LiCF 3 SO 3 , LiN (SO 2 CF 3 ) 2 , LiC (SO 2 CF). 3 ) 3 , LiAlCl 4 , LiSiF 6 , LiCl, difluoro [oxorat-O, O'] lithium borate, lithium bisoxalate volate, LiBr and the like can be mentioned.
  • LiPF 6 is preferable because it can obtain high ionic conductivity and further improve the cycle characteristics.
  • the open circuit voltage (that is, battery voltage) in the fully charged state per pair of positive electrode 21 and negative electrode 22 may be less than 4.25V, but is preferably 4.25V or more, more preferably. May be designed to be 4.3 V or higher, and even more preferably 4.4 V or higher. A high energy density can be obtained by increasing the battery voltage.
  • the upper limit of the open circuit voltage per pair of positive electrode 21 and negative electrode 22 in the fully charged state is preferably 6 V or less, more preferably 4.6 V or less, and even more preferably 4.5 V or less.
  • a positive electrode active material, a conductive agent, and a binder are mixed to prepare a positive electrode mixture, and this positive electrode mixture is dispersed in a solvent such as N-methyl-2-pyrrolidone (NMP) to form a paste.
  • NMP N-methyl-2-pyrrolidone
  • a positive electrode mixture slurry of is applied to both sides of the positive electrode current collector 21A, the solvent is dried, and compression molding is performed by a roll press or the like to form the positive electrode active material layer 21B1 and the positive electrode active material layer 21B2. 21 is formed.
  • the positive electrode current collector exposed portion 21C1 and the positive electrode current collector exposed portion 21C2 are formed on the positive electrode 21.
  • a negative electrode active material and a binder are mixed to prepare a negative electrode mixture, and this negative electrode mixture is dispersed in a solvent such as N-methyl-2-pyrrolidone to prepare a paste-like negative electrode mixture slurry. To do. Next, this negative electrode mixture slurry is applied to both sides of the negative electrode current collector 22A, the solvent is dried, and compression molding is performed by a roll press or the like to form the negative electrode active material layer 22B1 and the negative electrode active material layer 22B2. 22 is made.
  • a solvent such as N-methyl-2-pyrrolidone
  • the negative electrode 22 has a negative electrode current collector exposed portion 22C1, a negative electrode current collector exposed portion 22C2, a negative electrode current collector exposed portion 22D1, and a negative electrode current collector exposed portion 22D2. To form.
  • the positive electrode tab 25 is attached to the positive electrode current collector exposed portion 21C1 by welding or the like, and the negative electrode tab 26 is attached to the negative electrode current collector exposed portion 22D1 by welding or the like.
  • the reinforcing metal layer 28 and the negative electrode tab 27 are superposed on the negative electrode current collector exposed portion 22C1 in this order, and then the reinforcing metal layer 28 and the negative electrode tab 27 are attached to the negative electrode current collector exposed portion 22C1 by welding.
  • the positive electrode 21 and the negative electrode 22 are wound around the separator 23.
  • the tip of the positive electrode tab 25 is welded to the safety valve mechanism 15, and the tips of the negative electrode tab 26 and the negative electrode tab 27 are welded to the battery can 11, and the wound positive electrode 21 and the negative electrode 22 are combined with a pair of insulating plates. It is sandwiched between 12 and 13 and stored inside the battery can 11.
  • the positive electrode 21 and the negative electrode 22 are housed inside the battery can 11, and then the electrolytic solution is injected into the battery can 11 to impregnate the separator 23.
  • the battery lid 14, the safety valve mechanism 15, and the heat-sensitive resistance element 16 are fixed to the open end of the battery can 11 by caulking via the sealing gasket 17. As a result, the battery shown in FIG. 1 is obtained.
  • the electrode body 20 is wound around the end of the negative electrode 22 on the winding center side together with the negative electrode current collector exposed portion 22C1 in a cylindrical reinforcing metal layer 24. have.
  • the strength of the central hole 20A of the electrode body 20 can be improved. Therefore, when the electrode body 20 expands and contracts due to charging and discharging of the battery and pressure is generated toward the central hole 20A of the electrode body 20, when pressure is generated. It is possible to suppress changes in the shape and size of the central hole 20A of the electrode body 20.
  • the electrode body 20 is operated and opened as the cell internal pressure release valve is opened. Rupture of the positive electrode 21 and the negative electrode 22 caused by the contraction phenomenon can be suppressed. Therefore, the unsafe phenomenon due to the physical short heat storage between the torn electrode ends can be suppressed, and the safety can be improved.
  • the winding center of the electrode body 20 has a structure in which the negative electrode current collector 22A is wound (that is, the same electrodes are adjacent to each other in the light direction of the electrode body 20), the winding center of the electrode body 20 is located at the winding center. It is not necessary to provide an insulating tape. Further, even when the negative electrode tab 27 and the reinforcing metal layer 24 have cut burrs, it is possible to suppress the occurrence of a short circuit at the winding center of the electrode body 20.
  • the expansion amount of the silicon-containing material during charging is several times larger than the expansion amount of the carbon-containing material, as the content of the second negative electrode active material in the negative electrode active material layer 22B1 and the negative electrode active material layer 22B1 increases, Due to the expansion of the electrode body 20 at the time of charging, the pressure acting toward the central hole 20A of the electrode body 20 increases.
  • the central hole 20A is reinforced by the cylindrical reinforcing metal layer 24, the second in the negative electrode active material layer 22B1 and the negative electrode active material layer 22B2.
  • the electronic device 100 includes an electronic circuit 110 of the main body of the electronic device and a battery pack 120.
  • the battery pack 120 is electrically connected to the electronic circuit 110 via the positive electrode terminal 123a and the negative electrode terminal 123b.
  • the electronic device 100 may have a structure in which the battery pack 120 can be attached and detached.
  • Examples of the electronic device 100 include a notebook personal computer, a tablet computer, a mobile phone (for example, a smartphone), a personal digital assistant (PDA), a display device (LCD (Liquid Crystal Display), and an EL (Electro Luminescence).
  • a notebook personal computer for example, a smartphone
  • a tablet computer for example, a mobile phone (for example, a smartphone), a personal digital assistant (PDA), a display device (LCD (Liquid Crystal Display), and an EL (Electro Luminescence).
  • PDA personal digital assistant
  • LCD Liquid Crystal Display
  • EL Electro Luminescence
  • Display electronic paper, etc.
  • imaging device for example, digital still camera, digital video camera, etc.
  • audio equipment for example, portable audio player
  • game equipment cordless phone handset, electronic book, electronic dictionary, radio, headphones, navigation System, memory card, pacemaker, hearing aid, power tool, electric shaver, refrigerator, air conditioner, TV, stereo, water heater, microwave oven, dishwasher, washing machine, dryer, lighting equipment, toys, medical equipment, robot, road conditioner
  • a signal device and the like can be mentioned, but the present invention is not limited to these.
  • the electronic circuit 110 includes, for example, a CPU (Central Processing Unit), a peripheral logic unit, an interface unit, a storage unit, and the like, and controls the entire electronic device 100.
  • a CPU Central Processing Unit
  • the battery pack 120 includes an assembled battery 121 and a charge / discharge circuit 122.
  • the battery pack 120 may further include an exterior material (not shown) that houses the assembled battery 121 and the charge / discharge circuit 122, if necessary.
  • the assembled battery 121 is configured by connecting a plurality of secondary batteries 121a in series and / or in parallel.
  • the plurality of secondary batteries 121a are connected, for example, in n parallel m series (n and m are positive integers).
  • FIG. 6 shows an example in which six secondary batteries 121a are connected in two parallels and three series (2P3S).
  • the secondary battery 121a the battery according to the first embodiment described above is used.
  • the battery pack 120 includes an assembled battery 121 composed of a plurality of secondary batteries 121a.
  • the battery pack 120 includes one secondary battery 121a instead of the assembled battery 121. It may be adopted.
  • the charge / discharge circuit 122 is a control unit that controls the charge / discharge of the assembled battery 121. Specifically, at the time of charging, the charging / discharging circuit 122 controls charging of the assembled battery 121. On the other hand, at the time of discharging (that is, when the electronic device 100 is used), the charging / discharging circuit 122 controls the discharging to the electronic device 100.
  • the exterior material for example, a case made of a metal, a polymer resin, a composite material thereof, or the like can be used.
  • the composite material include a laminate in which a metal layer and a polymer resin layer are laminated.
  • the center pin may be inserted into the center hole 20A of the electrode body 20.
  • the electrode body 20 has a cylindrical reinforcing metal layer 24 wound together with the negative electrode current collector exposed portion 22C1 at the end portion of the negative electrode body 22 on the winding center side, so that the electrode body 20 is an electrode body. It is possible to suppress the occurrence of buckling of the negative electrode 22 on the winding center side of 20.
  • the reinforcing metal layer 24 is provided on the negative electrode current collector exposed portion 22C1
  • the reinforcing metal layer 24 is provided on the negative electrode current collector exposed portion 22C2.
  • the negative electrode tab 27 may be provided on the reinforcing metal layer 24, may be provided between the negative electrode current collector exposed portion 22C2 and the reinforcing metal layer 24, or the negative electrode current collector. It may be provided on the exposed portion 22C1.
  • the negative electrode tab 27 is provided on the negative electrode current collector exposed portion 22C1, it is preferable that the negative electrode tab 27 and the reinforcing metal layer 24 overlap in the thickness direction of the negative electrode current collector 22A.
  • the negative electrode tab 27 and the reinforcing metal layer 24 can be attached to the negative electrode current collector 22A by one welding. Further, the negative electrode tab 27 may be provided between the negative electrode current collector exposed portion 22C1 and the reinforcing metal layer 24. Further, the reinforcing metal layer 24 and the negative electrode tab 27 may be provided side by side in the winding direction on the negative electrode current collector exposed portion 22C1, or the reinforcing metal layer 24 and the negative electrode tab 27 may be provided on the negative electrode current collector exposed portion 22C2. 27 and 27 may be provided side by side in the winding direction.
  • Example 1 (Positive electrode manufacturing process) The positive electrode was prepared as follows. First, a positive electrode mixture was obtained by mixing 91 parts by mass of lithium nickel composite oxide (NCA) as a positive electrode active material, 6 parts by mass of graphite as a conductive agent, and 3 parts by mass of polyvinylidene fluoride as a binder. By dispersing in N-methyl-2-pyrrolidone, a paste-like positive electrode mixture slurry was obtained. Next, a positive electrode mixture slurry was applied to both sides of a positive electrode current collector made of strip-shaped aluminum foil (15 ⁇ m thick), dried, and then compression-molded with a roll press to form a positive electrode active material layer. ..
  • NCA lithium nickel composite oxide
  • graphite as a conductive agent
  • polyvinylidene fluoride as a binder
  • the coating position of the positive electrode mixture slurry was adjusted so that the positive electrode current collector exposed portions were formed on both sides of the central portion in the longitudinal direction of the positive electrode.
  • both ends in the longitudinal direction of the positive electrode were cut so that the positive electrode active material layer and the tips of the positive electrode current collector were aligned at both ends in the longitudinal direction of the positive electrode.
  • an aluminum positive electrode tab was attached to the exposed portion of the positive electrode current collector to be located on the inner side surface side after winding by ultrasonic welding.
  • an insulating tape was attached to the exposed portion of the positive electrode current collector so as to cover the positive electrode tab.
  • the negative electrode was prepared as follows. First, 97 parts by mass of artificial graphite powder as a negative electrode active material and 3 parts by mass of polyvinylidene fluoride as a binder are mixed to obtain a negative electrode mixture, which is then dispersed in N-methyl-2-pyrrolidone to form a paste. Negative electrode mixture slurry was obtained. Next, a negative electrode mixture slurry was applied to both sides of a negative electrode current collector made of a strip-shaped copper foil (15 ⁇ m thick), dried, and then compression-molded with a roll press to form a negative electrode active material layer. ..
  • the coating position of the negative electrode mixture slurry was adjusted so that the negative electrode current collector exposed portions were formed on both ends of the negative electrode in the longitudinal direction.
  • a reinforcing metal layer and a nickel negative electrode tab are superposed in this order on the negative electrode current collector exposed portion to be located on the inner side surface of the central end after winding, and then the negative electrode current collector is exposed.
  • a reinforcing metal layer and a negative electrode tab were attached to the portion by ultrasonic welding.
  • a nickel negative electrode tab was attached by ultrasonic welding to the exposed negative electrode current collector, which is to be located on the inner surface of the outer peripheral end after winding.
  • the reinforcing metal layer as shown in Table 1, a rectangular Cu foil having a length of 1.6 turns and having the same width as the negative electrode current collector and a thickness of 50 ⁇ m was used. ..
  • the batteries were assembled as follows. First, the positive electrode and the negative electrode obtained as described above were laminated in the order of the negative electrode, the separator, the positive electrode, and the separator via a separator made of a microporous polyethylene biaxially stretched film having a thickness of 10 ⁇ m. Next, winding was started from one end side of the negative electrode to which the reinforcing metal layer and the negative electrode tab were attached, and the winding was performed many times to obtain a wound electrode body as a power generation element.
  • a non-aqueous electrolyte solution was prepared by dissolving LiPF 6 as an electrolyte salt in a solvent in which ethylene carbonate and methyl ethyl carbonate were mixed at a volume ratio of 1: 1 so as to have a concentration of 1 mol / dm 3 .
  • Example 2 In the process of manufacturing the negative electrode, 87 parts by mass of artificial graphite powder as the negative electrode active material, 10 parts by mass of the silicon-containing material (SiO) as the negative electrode active material, and 3 parts by mass of polyvinylidene polyvinylfluoride as the binder are mixed to obtain a negative electrode mixture.
  • a battery was obtained in the same manner as in Example 1 except for the above.
  • Examples 3 to 6 As shown in Table 1, a battery was obtained in the same manner as in Example 2 except that CuNi alloy foil, Ni foil, CuZn alloy foil, and CuZnNi alloy foil were used as the reinforcing metal layer in the process of manufacturing the negative electrode.
  • Examples 7 to 10 As shown in Table 1, a battery was obtained in the same manner as in Example 2 except that 10 ⁇ m, 20 ⁇ m, 100 ⁇ m, and 110 ⁇ m Cu foils were used as the reinforcing metal layer in the process of manufacturing the negative electrode.
  • Example 11 to 14 In the process of manufacturing the negative electrode, as shown in Table 1, the reinforcing metal layer was carried out except that a Cu foil having a length capable of winding 1.1 turns, 1.2 turns, 2 turns and 3 turns was used. A battery was obtained in the same manner as in Example 2.
  • Example 15 and 16 In the process of manufacturing the negative electrode, as shown in Table 1, a copper foil having a length of two turns and three turns and a thickness of 100 ⁇ m was used as the reinforcing metal layer in the same manner as in Example 2. I got a battery.
  • Example 17 In the process of manufacturing the negative electrode, 92 parts by mass of artificial graphite powder as the negative electrode active material, 5 parts by mass of the silicon-containing material (SiO) as the negative electrode active material, and 3 parts by mass of polyvinylidene fluoride as the binder are mixed to obtain a negative electrode mixture. It was. Further, as the reinforcing metal layer, as shown in Table 1, a copper foil having a length of 1.2 turns and a thickness of 20 ⁇ m was used. A battery was obtained in the same manner as in Example 2 except for these matters.
  • Example 18 In the process of manufacturing the negative electrode, 77 parts by mass of artificial graphite powder as the negative electrode active material, 20 parts by mass of the silicon-containing material (SiO) as the negative electrode active material, and 3 parts by mass of polyvinylidene polyvinylfluoride as the binder are mixed to obtain a negative electrode mixture.
  • a battery was obtained in the same manner as in Example 17 except for the above.
  • Example 19 (Positive electrode manufacturing process) The positive electrode was prepared as follows. First, a paste-like positive electrode mixture slurry was obtained in the same manner as in Example 1. Next, a positive electrode mixture slurry was applied to both sides of a positive electrode current collector made of strip-shaped aluminum foil (15 ⁇ m thick), dried, and then compression-molded with a roll press to form a positive electrode active material layer. .. At this time, the application position of the positive electrode mixture slurry was adjusted so that exposed portions of the positive electrode current collector were formed on both sides of one end portion in the longitudinal direction of the positive electrode.
  • a reinforcing metal layer and an aluminum positive electrode tab are superposed in this order on the positive electrode current collector exposed portion to be located on the inner side surface of the central end after winding, and then the positive electrode current collector is exposed.
  • a reinforcing metal layer and a positive electrode tab were attached to the portion by ultrasonic welding.
  • the reinforcing metal layer as shown in Table 1, a rectangular Al foil having a length of 1.6 turns and having the same width as the positive electrode current collector and a thickness of 100 ⁇ m was used. ..
  • the negative electrode was prepared as follows. First, a paste-like negative electrode mixture slurry was obtained in the same manner as in Example 1. Next, a negative electrode mixture slurry was applied to both sides of a negative electrode current collector made of a strip-shaped copper foil (15 ⁇ m thick), dried, and then compression-molded with a roll press to form a negative electrode active material layer. .. At this time, the coating position of the negative electrode mixture slurry was adjusted so that the negative electrode current collector exposed portions were formed on both sides of one end portion in the longitudinal direction of the negative electrode. Next, a nickel negative electrode tab was attached by ultrasonic welding to the exposed negative electrode current collector, which is to be located on the inner surface of the outer peripheral end after winding. Next, an insulating tape was attached to the exposed negative electrode current collector so as to cover the negative electrode tab.
  • the batteries were assembled as follows. First, the positive electrode and the negative electrode obtained as described above were laminated in the order of the negative electrode, the separator, the positive electrode, and the separator via a separator made of a microporous polyethylene biaxially stretched film having a thickness of 10 ⁇ m. Next, winding was started from one end side of the positive electrode to which the reinforcing metal layer and the positive electrode tab were attached, and the winding was performed many times to obtain a wound electrode body as a power generation element. In the subsequent steps, a cylindrical battery was obtained in the same manner as in Example 1.
  • Example 20 A battery was obtained in the same manner as in Example 19 except that the material of the negative electrode mixture and the compounding ratio thereof were the same as in Example 2 in the process of producing the negative electrode.
  • Example 21 As shown in Table 1, a battery was obtained in the same manner as in Example 20 except that a Ti foil having a thickness of 50 ⁇ m was used as the reinforcing metal layer in the process of manufacturing the negative electrode.
  • Example 1 In the process of manufacturing the negative electrode, the same as in Example 1 except that a reinforcing metal layer is not provided on the exposed portion of the negative electrode current collector and a nickel negative electrode tab is directly attached to the exposed portion of the negative electrode current collector by ultrasonic welding. I got a battery.
  • Comparative Example 2 A battery was obtained in the same manner as in Comparative Example 1 except that the compounding ratio of the material of the negative electrode mixture was the same as in Example 17 in the process of producing the negative electrode.
  • Comparative Example 4 A battery was obtained in the same manner as in Comparative Example 3 except that a resin film was attached to the exposed portion of the positive electrode current collector in the process of producing the positive electrode.
  • a resin film as shown in Table 1, a rectangular polypropylene (PP) resin having a thickness of 500 ⁇ m, which has a length that can be wound 1.6 times and has the same width as the positive electrode current collector. A film was used.
  • Comparative Example 5 A battery was obtained in the same manner as in Comparative Example 3 except that the central hole reinforcing portion of the electrode body was formed by winding the positive electrode 1.6 times at the beginning of winding of the winding type electrode body.
  • Comparative Example 5 A battery was obtained in the same manner as in Comparative Example 2 except that the central hole reinforcing portion of the electrode body was formed by winding the negative electrode 1.6 times at the beginning of winding of the winding type electrode body.
  • the batteries in which the central hole is reinforced by the cylindrical reinforcing metal layer are compared with the batteries in which the central hole is not reinforced by the cylindrical reinforcing metal layer (Comparative Examples 1 to 3).
  • the incidence of shorts and buckling can be reduced.
  • Batteries in which the central hole is reinforced by a cylindrical reinforcing metal layer are short-circuited and buckled as compared with batteries in which the central hole is reinforced by a cylindrical resin film (Comparative Example 4). The incidence of bending can be reduced.
  • the thickness of the reinforcing metal layer is preferably 20 ⁇ m or more (Examples 7 to 10).
  • the number of turns of the reinforcing metal layer is preferably 1.2 or more (Examples 11 to 14).

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Abstract

This battery comprises a winding-type electrode body provided with a positive electrode and a negative electrode. The negative electrode comprises: a negative electrode current collector having a first surface and a second surface; a negative electrode active material layer provided on the first surface and the second surface so that the first surface is exposed at the winding center side end part of the electrode body; and a metal layer provided on the first surface exposed at the winding center side end part. The metal layer is wound in cylindrical form.

Description

電池battery
　本発明は、電池に関する。 The present invention relates to a battery.
　近年、長尺状の正極および負極を巻回した巻回型電池は広く用いられている。この巻回型電池では、電池特性を改善するために、様々な検討がなされている。 In recent years, a wound battery in which a long positive electrode and a negative electrode are wound is widely used. In this wound type battery, various studies have been made in order to improve the battery characteristics.
　例えば特許文献１には、巻回型の電池において、巻芯側の最内径や段差等の変形による歪みが掛かり易い箇所を保護する目的で、正極および負極の巻芯側の端に樹脂フィルムを配置する技術が開示されている。 For example, in Patent Document 1, in a winding type battery, a resin film is provided at the ends of the positive electrode and the negative electrode on the winding core side for the purpose of protecting the innermost diameter on the winding core side and the portion easily distorted due to deformation such as a step. The technique of placement is disclosed.
特開２００５－１３５６７４号公報Japanese Unexamined Patent Publication No. 2005-135674
　しかしながら、特許文献１に記載の電池では、樹脂フィルムの形状維持強度が十分ではないため、充放電を繰り返すと、巻回中心側において電極に座屈が発生することがある。このように電極に座屈が発生すると、電池の信頼性や安全性が低下する。本明細書において、“座屈”とは、巻回中心側の電極切断端（例えば正極切断端）から数ｍｍ域の局所的な曲がりのことを言い、“座屈”の発生は、セパレータを突き破り、対極（例えば負極）と物理的な短絡（ショート）を引き起こす原因となる。 However, in the battery described in Patent Document 1, the shape-maintaining strength of the resin film is not sufficient, so that the electrode may buckle on the winding center side when charging and discharging are repeated. When buckling occurs in the electrodes in this way, the reliability and safety of the battery deteriorate. In the present specification, "buckling" means a local bending in a region of several mm from the electrode cutting end (for example, the positive electrode cutting end) on the winding center side, and the occurrence of "buckling" refers to the separator. It may break through and cause a physical short circuit (short circuit) with the counter electrode (for example, the negative electrode).
　本発明の目的は、巻回中心側において電極に座屈が発生することを抑制することができる電池を提供することにある。 An object of the present invention is to provide a battery capable of suppressing buckling of an electrode on the winding center side.
　上述の課題を解決するために、第１の発明は、
　正極と、負極とを備える巻回型の電極体を備え、
　負極は、
　第１の面および第２の面を有する負極集電体と、
　電極体の巻回中心側端部において第１の面が露出するように、第１の面および第２の面上に設けられた負極活物質層と、
　巻回中心側端部において露出した第１の面上に設けられた金属層と
　を備え、
　金属層は、筒状に巻回されている電池である。 In order to solve the above-mentioned problems, the first invention
A wound electrode body including a positive electrode and a negative electrode is provided.
The negative electrode is
A negative electrode current collector having a first surface and a second surface,
A negative electrode active material layer provided on the first surface and the second surface so that the first surface is exposed at the winding center side end of the electrode body.
It is provided with a metal layer provided on the exposed first surface at the winding center side end.
The metal layer is a battery that is wound in a tubular shape.
　第２の発明は、
　正極と、負極とを備える巻回型の電極体を備え、
　正極および負極のうち、電極体の最内周に位置する電極は、
　第１の面および第２の面を有する集電体と、
　電極体の巻回中心側の端部において第１の面が露出するように、第１の面および第２の面上に設けられた活物質層と、
　巻回中心側の端部において露出した第１の面上に設けられた金属層と
　を備え、
　金属層は、筒状に巻回されている電池である。 The second invention is
A wound electrode body including a positive electrode and a negative electrode is provided.
Of the positive electrode and the negative electrode, the electrode located on the innermost circumference of the electrode body is
A current collector having a first surface and a second surface,
An active material layer provided on the first surface and the second surface so that the first surface is exposed at the end of the electrode body on the winding center side.
It is provided with a metal layer provided on the exposed first surface at the end on the winding center side.
The metal layer is a battery that is wound in a tubular shape.
　本発明によれば、巻回中心側において電極に座屈が発生することを抑制することができる。 According to the present invention, it is possible to suppress the occurrence of buckling of the electrode on the winding center side.
本発明の第１の実施形態に係る非水電解質二次電池の構成の一例を示す縦断面図である。It is a vertical sectional view which shows an example of the structure of the non-aqueous electrolyte secondary battery which concerns on 1st Embodiment of this invention. 巻回型電極体の構成の一例を示す横断面図である。It is sectional drawing which shows an example of the structure of the winding type electrode body. 巻き解かれた状態の巻回型電極体の構成の一例を示す断面図である。It is sectional drawing which shows an example of the structure of the winding type electrode body in the unwound state. 負極の巻回中心側の端部の構成の一例を示す斜視図である。It is a perspective view which shows an example of the structure of the end part on the winding center side of a negative electrode. 補強金属層が設けられていない巻回型電極体の構成の一例を示す横断面図である。It is sectional drawing which shows an example of the structure of the winding type electrode body which is not provided with a reinforcing metal layer. 本発明の第２の実施形態に係る電子機器の構成の一例を示すブロック図である。It is a block diagram which shows an example of the structure of the electronic device which concerns on 2nd Embodiment of this invention.
　本発明の実施形態について以下の順序で説明する。
１　第１の実施形態（円筒型電池の例）
２　第２の実施形態（電子機器の例）
３　変形例 Embodiments of the present invention will be described in the following order.
1 First embodiment (example of cylindrical battery)
2 Second embodiment (example of electronic device)
3 Modification example
＜１　第１の実施形態＞
［電池の構成］
　以下、図１を参照しながら、本発明の第１の実施形態に係る非水電解質二次電池（以下単に「電池」という。）の構成の一例について説明する。この電池は、例えば、負極の容量が、電極反応物質であるリチウム（Ｌｉ）の吸蔵および放出による容量成分により表されるいわゆるリチウムイオン二次電池である。この電池はいわゆる円筒型といわれるものであり、ほぼ中空円柱状の電池缶１１の内部に、一対の帯状の正極２１と帯状の負極２２とがセパレータ２３を介して積層し巻回された巻回型電極体２０（以下単に「電極体２０」という。）を備える。電池缶１１は、ニッケル（Ｎｉ）のめっきがされた鉄（Ｆｅ）により構成され、一端部が閉鎖され他端部が開放されている。電池缶１１の内部には、液状の電解質としての電解液が注入され、正極２１、負極２２およびセパレータ２３に含浸されている。また、電極体２０を挟むように巻回周面に対して垂直に一対の絶縁板１２、１３がそれぞれ配置されている。 <1 First Embodiment>
[Battery configuration]
Hereinafter, an example of the configuration of the non-aqueous electrolyte secondary battery (hereinafter, simply referred to as “battery”) according to the first embodiment of the present invention will be described with reference to FIG. This battery is, for example, a so-called lithium ion secondary battery in which the capacity of the negative electrode is represented by a capacity component due to occlusion and release of lithium (Li), which is an electrode reactant. This battery is a so-called cylindrical type, and a pair of strip-shaped positive electrodes 21 and strip-shaped negative electrodes 22 are laminated and wound inside a substantially hollow cylindrical battery can 11 via a separator 23. A mold electrode body 20 (hereinafter, simply referred to as “electrode body 20”) is provided. The battery can 11 is made of iron (Fe) plated with nickel (Ni), and one end thereof is closed and the other end is open. An electrolytic solution as a liquid electrolyte is injected into the inside of the battery can 11, and the positive electrode 21, the negative electrode 22, and the separator 23 are impregnated. Further, a pair of insulating plates 12 and 13 are arranged perpendicular to the winding peripheral surface so as to sandwich the electrode body 20.
　電池缶１１の開放端部には、電池蓋１４と、この電池蓋１４の内側に設けられた安全弁機構１５および熱感抵抗素子（Positive Temperature Coefficient；ＰＴＣ素子）１６とが、封口ガスケット１７を介してかしめられることにより取り付けられている。これにより、電池缶１１の内部は密閉されている。電池蓋１４は、例えば、電池缶１１と同様の材料により構成されている。安全弁機構１５は、電池蓋１４と電気的に接続されており、内部短絡あるいは外部からの加熱等により電池の内圧が一定以上となった場合に、ディスク板１５Ａが反転して電池蓋１４と電極体２０との電気的接続を切断するようになっている。封口ガスケット１７は、例えば、絶縁材料により構成されており、表面にはアスファルトが塗布されている。 At the open end of the battery can 11, a battery lid 14, a safety valve mechanism 15 provided inside the battery lid 14, and a heat-sensitive resistance element (Positive Temperature Coefficient; PTC element) 16 are interposed via a sealing gasket 17. It is attached by being crimped. As a result, the inside of the battery can 11 is sealed. The battery lid 14 is made of, for example, the same material as the battery can 11. The safety valve mechanism 15 is electrically connected to the battery lid 14, and when the internal pressure of the battery exceeds a certain level due to an internal short circuit or heating from the outside, the disk plate 15A is inverted and the battery lid 14 and the electrode It is designed to disconnect the electrical connection with the body 20. The sealing gasket 17 is made of, for example, an insulating material, and the surface is coated with asphalt.
　電極体２０は、ほぼ円柱状を有している。電極体２０は、その第１の端面の中心から第２の端面の中心に向けて貫通する中心孔２０Ａを有している。この中心孔２０Ａは、電池缶１１内でガスが発生した場合に、ガスを電池缶１１の缶底側からそれとは反対の電池蓋１４側に誘導する流路として機能する。 The electrode body 20 has a substantially columnar shape. The electrode body 20 has a center hole 20A penetrating from the center of the first end face toward the center of the second end face. The central hole 20A functions as a flow path for guiding the gas from the can bottom side of the battery can 11 to the battery lid 14 side opposite to the gas when gas is generated in the battery can 11.
　正極２１には、アルミニウム（Ａｌ）等よりなる正極タブ２５が接続されており、負極２２には、ニッケル等よりなる負極タブ２６および負極タブ２７が接続されている。正極タブ２５は安全弁機構１５に溶接されることにより電池蓋１４と電気的に接続されており、負極タブ２６および負極タブ２７は電池缶１１に溶接され電気的に接続されている。 A positive electrode tab 25 made of aluminum (Al) or the like is connected to the positive electrode 21, and a negative electrode tab 26 and a negative electrode tab 27 made of nickel or the like are connected to the negative electrode 22. The positive electrode tab 25 is electrically connected to the battery lid 14 by being welded to the safety valve mechanism 15, and the negative electrode tab 26 and the negative electrode tab 27 are welded to the battery can 11 and electrically connected.
　以下、図２～図４を参照しながら、電池を構成する正極２１、負極２２、セパレータ２３、および電解液について順次説明する。図２、図３では、正極２１および負極２２のうち負極２２が、電極体２０の最内周に位置する電極である例について示されているが、正極２１が、電極体２０の最内周に位置する電極であってもよい。 Hereinafter, the positive electrode 21, the negative electrode 22, the separator 23, and the electrolytic solution constituting the battery will be sequentially described with reference to FIGS. 2 to 4. 2 and 3 show an example in which the negative electrode 22 of the positive electrode 21 and the negative electrode 22 is an electrode located on the innermost circumference of the electrode body 20, but the positive electrode 21 is the innermost circumference of the electrode body 20. It may be an electrode located at.
（正極）
　正極２１は、内側面（第３の面）２１Ｓ１および外側面（第４の面）２１Ｓ２を有する正極集電体２１Ａと、正極集電体２１Ａの内側面２１Ｓ１に設けられた正極活物質層２１Ｂ１と、正極集電体２１Ａの外側面２１Ｓ２に設けられた正極活物質層２１Ｂ２とを備える。本明細書において、“内側面”とは、巻回中心側に位置する面を意味し、“外側面”とは、巻回中心とは反対側に位置する面を意味する。 (Positive electrode)
The positive electrode 21 includes a positive electrode current collector 21A having an inner side surface (third surface) 21S1 and an outer surface (fourth surface) 21S2, and a positive electrode active material layer 21B1 provided on the inner side surface 21S1 of the positive electrode current collector 21A. And the positive electrode active material layer 21B2 provided on the outer surface 21S2 of the positive electrode current collector 21A. In the present specification, the "inner surface" means a surface located on the winding center side, and the "outer surface" means a surface located on the side opposite to the winding center.
　正極２１の巻回中心側の端部において、正極活物質層２１Ｂ１と正極集電体２１Ａの先端が揃っていると共に、正極活物質層２１Ｂ２と正極集電体２１Ａの先端が揃っている。正極集電体２１Ａの巻回中心側の端部の内側面２１Ｓ１は、当該内側面２１Ｓ１が露出しないように正極活物質層２１Ｂ１により覆われている。正極集電体２１Ａの巻回中心側の端部の外側面２１Ｓ２は、当該外側面２１Ｓ２が露出しないように正極活物質層２１Ｂ２により覆われている。 At the end of the positive electrode 21 on the winding center side, the tips of the positive electrode active material layer 21B1 and the positive electrode current collector 21A are aligned, and the tips of the positive electrode active material layer 21B2 and the positive electrode current collector 21A are aligned. The inner side surface 21S1 of the end portion of the positive electrode current collector 21A on the winding center side is covered with the positive electrode active material layer 21B1 so that the inner side surface 21S1 is not exposed. The outer surface 21S2 at the end of the positive electrode current collector 21A on the winding center side is covered with the positive electrode active material layer 21B2 so that the outer surface 21S2 is not exposed.
　正極活物質層２１Ｂ１および正極活物質層２１Ｂ２の抵抗は、正極集電体２１Ａの抵抗に比べて１桁以上低い。したがって、上述のように正極集電体２１Ａの巻回中心側の端部が正極活物質層２１Ｂ１および正極活物質層２１Ｂ２が覆われている場合には、正極集電体２１Ａの巻回中心側の端部が正極活物質層２１Ｂ１および正極活物質層２１Ｂ２により覆われていない場合（すなわち正極集電体２１Ａの巻回中心側の端部が露出している場合）に比べて、正極２１と負極２２がショートするリスクを低減することができる。 The resistance of the positive electrode active material layer 21B1 and the positive electrode active material layer 21B2 is one digit or more lower than the resistance of the positive electrode current collector 21A. Therefore, when the positive electrode active material layer 21B1 and the positive electrode active material layer 21B2 are covered at the end of the positive electrode current collector 21A on the winding center side as described above, the winding center side of the positive electrode current collector 21A Compared with the case where the end portion of the positive electrode active material layer 21B1 and the positive electrode active material layer 21B2 is not covered (that is, the end portion on the winding center side of the positive electrode current collector 21A is exposed), the positive electrode 21 The risk of short-circuiting the negative electrode 22 can be reduced.
　正極２１の巻回外周側の端部において、正極活物質層２１Ｂ１と正極集電体２１Ａの先端が揃っていると共に、正極活物質層２１Ｂ２と正極集電体２１Ａの先端が揃っている。正極２１の巻回外周側の端部の内側面２１Ｓ１は、当該内側面２１Ｓ１が露出しないように正極活物質層２１Ｂ１により覆われている。正極２１の巻回外周側の端部の外側面２１Ｓ２は、当該外側面２１Ｓ２が露出しないように正極活物質層２１Ｂ２により覆われている。 At the end of the positive electrode 21 on the winding outer peripheral side, the tips of the positive electrode active material layer 21B1 and the positive electrode current collector 21A are aligned, and the tips of the positive electrode active material layer 21B2 and the positive electrode current collector 21A are aligned. The inner side surface 21S1 of the winding outer peripheral side end of the positive electrode 21 is covered with the positive electrode active material layer 21B1 so that the inner side surface 21S1 is not exposed. The outer surface 21S2 of the winding outer peripheral end of the positive electrode 21 is covered with the positive electrode active material layer 21B2 so that the outer surface 21S2 is not exposed.
　上述のように正極集電体２１Ａの巻回外周側の端部が正極活物質層２１Ｂ１および正極活物質層２１Ｂ２が覆われている場合には、正極集電体２１Ａの巻回外周側の端部が正極活物質層２１Ｂ１および正極活物質層２１Ｂ２により覆われていない場合（すなわち正極集電体２１Ａの巻回外周側の端部が露出している場合）に比べて、正極２１と負極２２がショートするリスクを低減することができる。 When the positive electrode active material layer 21B1 and the positive electrode active material layer 21B2 are covered by the winding outer peripheral end of the positive electrode current collector 21A as described above, the winding outer peripheral end of the positive electrode current collector 21A The positive electrode 21 and the negative electrode 22 are compared with the case where the portion is not covered by the positive electrode active material layer 21B1 and the positive electrode active material layer 21B2 (that is, the end portion on the winding outer peripheral side of the positive electrode current collector 21A is exposed). Can reduce the risk of short circuit.
　正極２１の中周部の内側面２１Ｓ１および外側面２１Ｓ２には、図３に示すように、正極活物質層２１Ｂ１および正極活物質層２１Ｂ２が設けられず、正極集電体２１Ａの内側面２１Ｓ１および外側面２１Ｓ２が露出した正極集電体露出部２１Ｃ１および正極集電体露出部２１Ｃ２が設けられている。ここで、正極２１の中周部とは、巻回中心側の端部と巻回外周側の端部の間に部分のことをいう。正極集電体露出部２１Ｃ１または正極集電体露出部２１Ｃ２には、正極タブ２５が設けられている。但し、図２では、正極集電体露出部２１Ｃ１に正極タブ２５が設けられた例が示されている。正極タブ２５は、絶縁テープ（図示せず）により覆われていてもよい。 As shown in FIG. 3, the positive electrode active material layer 21B1 and the positive electrode active material layer 21B2 are not provided on the inner side surface 21S1 and the outer side surface 21S2 of the middle peripheral portion of the positive electrode 21, and the inner side surface 21S1 and the positive electrode current collector 21A A positive electrode current collector exposed portion 21C1 and a positive electrode current collector exposed portion 21C2 with the outer side surface 21S2 exposed are provided. Here, the middle peripheral portion of the positive electrode 21 means a portion between the end portion on the winding center side and the end portion on the winding outer peripheral side. The positive electrode current collector exposed portion 21C1 or the positive electrode current collector exposed portion 21C2 is provided with a positive electrode tab 25. However, FIG. 2 shows an example in which the positive electrode tab 25 is provided on the positive electrode current collector exposed portion 21C1. The positive electrode tab 25 may be covered with insulating tape (not shown).
　正極集電体２１Ａは、例えば、アルミニウム箔、ニッケル箔あるいはステンレス箔等の金属箔により構成されている。 The positive electrode current collector 21A is made of, for example, a metal foil such as an aluminum foil, a nickel foil, or a stainless steel foil.
　正極活物質層２１Ｂ１および正極活物質層２１Ｂ２は、リチウムを吸蔵および放出することが可能な正極活物質を含む。正極活物質層２１Ｂ１および正極活物質層２１Ｂ２は、必要に応じてバインダーおよび導電剤のうちの少なくとも１種をさらに含んでいてもよい。 The positive electrode active material layer 21B1 and the positive electrode active material layer 21B2 contain a positive electrode active material capable of occluding and releasing lithium. The positive electrode active material layer 21B1 and the positive electrode active material layer 21B2 may further contain at least one of a binder and a conductive agent, if necessary.
（正極活物質）
　リチウムを吸蔵および放出することが可能な正極活物質としては、例えば、リチウム酸化物、リチウムリン酸化物、リチウム硫化物またはリチウムを含む層間化合物等のリチウム含有化合物が適当であり、これらの２種以上を混合して用いてもよい。エネルギー密度を高くするには、リチウムと遷移金属元素と酸素（Ｏ）とを含むリチウム含有化合物が好ましい。このようなリチウム含有化合物としては、例えば、式（Ａ）に示した層状岩塩型の構造を有するリチウム複合酸化物、式（Ｂ）に示したオリビン型の構造を有するリチウム複合リン酸塩等が挙げられる。リチウム含有化合物としては、遷移金属元素として、コバルト（Ｃｏ）、ニッケル（Ｎｉ）、マンガン（Ｍｎ）および鉄（Ｆｅ）からなる群のうちの少なくとも１種を含むものであればより好ましい。このようなリチウム含有化合物としては、例えば、式（Ｃ）、式（Ｄ）もしくは式（Ｅ）に示した層状岩塩型の構造を有するリチウム複合酸化物、式（Ｆ）に示したスピネル型の構造を有するリチウム複合酸化物、または式（Ｇ）に示したオリビン型の構造を有するリチウム複合リン酸塩等が挙げられ、具体的には、Ｌｉ１Ｎｉ０．５０Ｃｏ０．２０Ｍｎ０．３０Ｏ２、Ｌｉ１ＣｏＯ２、Ｌｉ１ＮｉＯ２、Ｌｉ１ＮｉａＣｏ１－ａＯ２（０＜ａ＜１）、Ｌｉ１Ｍｎ２Ｏ４またはＬｉ１ＦｅＰＯ４等がある。 (Positive electrode active material)
As the positive electrode active material capable of occluding and releasing lithium, for example, a lithium-containing compound such as a lithium oxide, a lithium phosphorus oxide, a lithium sulfide or an interlayer compound containing lithium is suitable, and these two types are suitable. The above may be mixed and used. In order to increase the energy density, a lithium-containing compound containing lithium, a transition metal element, and oxygen (O) is preferable. Examples of such a lithium-containing compound include a lithium composite oxide having a layered rock salt type structure represented by the formula (A), a lithium composite phosphate having an olivine type structure represented by the formula (B), and the like. Can be mentioned. The lithium-containing compound is more preferably one containing at least one of the group consisting of cobalt (Co), nickel (Ni), manganese (Mn) and iron (Fe) as a transition metal element. Examples of such a lithium-containing compound include a lithium composite oxide having a layered rock salt type structure represented by the formula (C), the formula (D) or the formula (E), and a spinel type represented by the formula (F). Examples thereof include a lithium composite oxide having a structure and a lithium composite phosphate having an olivine-type structure represented by the formula (G). Specifically, Li 1 Ni 0.50 Co 0.20 Mn 0. There are 30 O 2 , Li 1 CoO 2 , Li 1 NiO 2 , Li 1 Ni a Co 1-a O 2 (0 <a <1), Li 1 Mn 2 O 4 or Li 1 FePO 4 .
　ＬｉｐＮｉ（１－ｑ－ｒ）ＭｎｑＭ１ｒＯ（２－ｙ）Ｘｚ　・・・（Ａ）
（但し、式（Ａ）中、Ｍ１は、ニッケル、マンガンを除く２族～１５族から選ばれる元素のうち少なくとも一種を示す。Ｘは、酸素以外の１６族元素および１７族元素のうち少なくとも１種を示す。ｐ、ｑ、ｙ、ｚは、０≦ｐ≦１．５、０≦ｑ≦１．０、０≦ｒ≦１．０、－０．１０≦ｙ≦０．２０、０≦ｚ≦０．２の範囲内の値である。） Li p Ni (1-q-r) Mn q M1 r O (2-y) X z ... (A)
(However, in the formula (A), M1 represents at least one of the elements selected from groups 2 to 15 excluding nickel and manganese. X is at least one of the group 16 and group 17 elements other than oxygen. Indicates a species. P, q, y, z are 0 ≦ p ≦ 1.5, 0 ≦ q ≦ 1.0, 0 ≦ r ≦ 1.0, −0.10 ≦ y ≦ 0.20, 0 ≦ It is a value within the range of z ≦ 0.2.)
　ＬｉａＭ２ｂＰＯ４　・・・（Ｂ）
（但し、式（Ｂ）中、Ｍ２は、２族～１５族から選ばれる元素のうち少なくとも一種を示す。ａ、ｂは、０≦ａ≦２．０、０．５≦ｂ≦２．０の範囲内の値である。） Li a M2 b PO 4 ... (B)
(However, in the formula (B), M2 represents at least one of the elements selected from groups 2 to 15. a and b are 0 ≦ a ≦ 2.0 and 0.5 ≦ b ≦ 2.0. It is a value within the range of.)
　ＬｉｆＭｎ(１－ｇ－ｈ)ＮｉｇＭ３ｈＯ(２－ｊ)Ｆｋ　・・・（Ｃ）
（但し、式（Ｃ）中、Ｍ３は、コバルト、マグネシウム（Ｍｇ）、アルミニウム、ホウ素（Ｂ）、チタン（Ｔｉ）、バナジウム（Ｖ）、クロム（Ｃｒ）、鉄、銅、亜鉛（Ｚｎ）、ジルコニウム（Ｚｒ）、モリブデン（Ｍｏ）、スズ（Ｓｎ）、カルシウム（Ｃａ）、ストロンチウム（Ｓｒ）およびタングステン（Ｗ）からなる群のうちの少なくとも１種を表す。ｆ、ｇ、ｈ、ｊおよびｋは、０．８≦ｆ≦１．２、０＜ｇ＜０．５、０≦ｈ≦０．５、ｇ＋ｈ＜１、－０．１≦ｊ≦０．２、０≦ｋ≦０．１の範囲内の値である。なお、リチウムの組成は充放電の状態によって異なり、ｆの値は完全放電状態における値を表している。） Li f Mn (1-g-h) Ni g M3 h O (2-j) F k ... (C)
(However, in the formula (C), M3 is cobalt, magnesium (Mg), aluminum, boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron, copper, zinc (Zn), Represents at least one of the group consisting of zirconium (Zr), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr) and tungsten (W). F, g, h, j and k. 0.8 ≦ f ≦ 1.2, 0 <g <0.5, 0 ≦ h ≦ 0.5, g + h <1, −0.1 ≦ j ≦ 0.2, 0 ≦ k ≦ 0.1 The composition of lithium differs depending on the state of charge and discharge, and the value of f represents the value in the state of complete discharge.)
　ＬｉｍＮｉ(１－ｎ)Ｍ４ｎＯ(２－ｐ)Ｆｑ　・・・（Ｄ）
（但し、式（Ｄ）中、Ｍ４は、コバルト、マンガン、マグネシウム、アルミニウム、ホウ素、チタン、バナジウム、クロム、鉄、銅、亜鉛、モリブデン、スズ、カルシウム、ストロンチウムおよびタングステンからなる群のうちの少なくとも１種を表す。ｍ、ｎ、ｐおよびｑは、０．８≦ｍ≦１．２、０．００５≦ｎ≦０．５、－０．１≦ｐ≦０．２、０≦ｑ≦０．１の範囲内の値である。なお、リチウムの組成は充放電の状態によって異なり、ｍの値は完全放電状態における値を表している。） Li m Ni (1-n) M4 n O (2-p) F q ... (D)
(However, in formula (D), M4 is at least in the group consisting of cobalt, manganese, magnesium, aluminum, boron, titanium, vanadium, chromium, iron, copper, zinc, molybdenum, tin, calcium, strontium and tungsten. Represents one type. M, n, p and q are 0.8 ≦ m ≦ 1.2, 0.005 ≦ n ≦ 0.5, −0.1 ≦ p ≦ 0.2, 0 ≦ q ≦ 0. It is a value within the range of .1. The composition of lithium differs depending on the state of charge and discharge, and the value of m represents the value in the state of complete discharge.)
　ＬｉｒＣｏ(１－ｓ)Ｍ５ｓＯ(２－ｔ)Ｆｕ　・・・（Ｅ）
（但し、式（Ｅ）中、Ｍ５は、ニッケル、マンガン、マグネシウム、アルミニウム、ホウ素、チタン、バナジウム、クロム、鉄、銅、亜鉛、モリブデン、スズ、カルシウム、ストロンチウムおよびタングステンからなる群のうちの少なくとも１種を表す。ｒ、ｓ、ｔおよびｕは、０．８≦ｒ≦１．２、０≦ｓ＜０．５、－０．１≦ｔ≦０．２、０≦ｕ≦０．１の範囲内の値である。なお、リチウムの組成は充放電の状態によって異なり、ｒの値は完全放電状態における値を表している。） Li r Co (1-s) M5 s O (2-t) Fu ... (E)
(However, in formula (E), M5 is at least in the group consisting of nickel, manganese, magnesium, aluminum, boron, titanium, vanadium, chromium, iron, copper, zinc, molybdenum, tin, calcium, strontium and tungsten. Represents one type. R, s, t and u are 0.8 ≦ r ≦ 1.2, 0 ≦ s <0.5, −0.1 ≦ t ≦ 0.2, 0 ≦ u ≦ 0.1. The composition of lithium differs depending on the state of charge and discharge, and the value of r represents the value in the state of complete discharge.)
　ＬｉｖＭｎ２－ｗＭ６ｗＯｘＦｙ　・・・（Ｆ）
（但し、式（Ｆ）中、Ｍ６は、コバルト、ニッケル、マグネシウム、アルミニウム、ホウ素、チタン、バナジウム、クロム、鉄、銅、亜鉛、モリブデン、スズ、カルシウム、ストロンチウムおよびタングステンからなる群のうちの少なくとも１種を表す。ｖ、ｗ、ｘおよびｙは、０．９≦ｖ≦１．１、０≦ｗ≦０．６、３．７≦ｘ≦４．１、０≦ｙ≦０．１の範囲内の値である。なお、リチウムの組成は充放電の状態によって異なり、ｖの値は完全放電状態における値を表している。） Li v Mn 2-w M6 w O x F y ... (F)
(However, in formula (F), M6 is at least in the group consisting of cobalt, nickel, magnesium, aluminum, boron, titanium, vanadium, chromium, iron, copper, zinc, molybdenum, tin, calcium, strontium and tungsten. Represents one type. V, w, x and y are 0.9 ≦ v ≦ 1.1, 0 ≦ w ≦ 0.6, 3.7 ≦ x ≦ 4.1, 0 ≦ y ≦ 0.1. It is a value within the range. The composition of lithium differs depending on the state of charge and discharge, and the value of v represents the value in the state of complete discharge.)
　ＬｉｚＭ７ＰＯ４　・・・（Ｇ）
（但し、式（Ｇ）中、Ｍ７は、コバルト、マンガン、鉄、ニッケル、マグネシウム、アルミニウム、ホウ素、チタン、バナジウム、ニオブ（Ｎｂ）、銅、亜鉛、モリブデン、カルシウム、ストロンチウム、タングステンおよびジルコニウムからなる群のうちの少なくとも１種を表す。ｚは、０．９≦ｚ≦１．１の範囲内の値である。なお、リチウムの組成は充放電の状態によって異なり、ｚの値は完全放電状態における値を表している。） Li z M7PO 4 ... (G)
(However, in formula (G), M7 is composed of cobalt, manganese, iron, nickel, magnesium, aluminum, boron, titanium, vanadium, niobium (Nb), copper, zinc, molybdenum, calcium, strontium, tungsten and zirconium. Represents at least one of the groups. Z is a value within the range of 0.9 ≦ z ≦ 1.1. The composition of lithium differs depending on the state of charge and discharge, and the value of z is the state of complete discharge. Represents the value in.)
　ニッケルを含むリチウム複合酸化物としては、リチウムとニッケルとコバルトとマンガンと酸素とを含むリチウム複合酸化物（ＮＣＭ）、リチウムとニッケルとコバルトとアルミニウムと酸素とを含むリチウム複合酸化物（ＮＣＡ）等を用いてもよい。ニッケルを含むリチウム複合酸化物としては、具体的には、以下の式（Ｈ）または式（Ｉ）に示したものを用いてもよい。 Examples of the lithium composite oxide containing nickel include a lithium composite oxide containing lithium, nickel, cobalt, manganese and oxygen (NCM), and a lithium composite oxide containing lithium, nickel, cobalt, aluminum and oxygen (NCA). May be used. Specifically, as the lithium composite oxide containing nickel, those represented by the following formula (H) or formula (I) may be used.
　Ｌｉｖ１Ｎｉｗ１Ｍ１’ｘ１Ｏｚ１　・・・（Ｈ）
（式中、０＜ｖ１＜２、ｗ１＋ｘ１≦１、０．２≦ｗ１≦１、０≦ｘ１≦０．７、０＜ｚ＜３であり、Ｍ１’は、コバルト、鉄、マンガン、銅、亜鉛、アルミニウム、クロム、バナジウム、チタン、マグネシウムおよびジルコニウム等の遷移金属からなる元素を少なくとも１種類以上である。） Li v1 Ni w1 M1 'x1 O z1 ··· (H)
(In the formula, 0 <v1 <2, w1 + x1 ≦ 1, 0.2 ≦ w1 ≦ 1, 0 ≦ x1 ≦ 0.7, 0 <z <3, and M1 ′ is cobalt, iron, manganese, copper, At least one element composed of transition metals such as zinc, aluminum, chromium, vanadium, titanium, magnesium and zirconium.)
　Ｌｉｖ２Ｎｉｗ２Ｍ２’ｘ２Ｏｚ２　・・・（Ｉ）
（式中、０＜ｖ２＜２、ｗ２＋ｘ２≦１、０．６５≦ｗ２≦１、０≦ｘ２≦０．３５、０＜ｚ２＜３であり、Ｍ２’は、コバルト、鉄、マンガン、銅、亜鉛、アルミニウム、クロム、バナジウム、チタン、マグネシウムおよびジルコニウム等の遷移金属からなる元素を少なくとも１種類以上である。） Li v2 Ni w2 M2 'x2 O z2 ··· (I)
(In the formula, 0 <v2 <2, w2 + x2 ≦ 1, 0.65 ≦ w2 ≦ 1, 0 ≦ x2 ≦ 0.35, 0 <z2 <3, and M2'is cobalt, iron, manganese, copper, At least one element composed of transition metals such as zinc, aluminum, chromium, vanadium, titanium, magnesium and zirconium.)
　リチウムを吸蔵および放出することが可能な正極活物質としては、これらの他にも、ＭｎＯ２、Ｖ２Ｏ５、Ｖ６Ｏ１３、ＮｉＳ、ＭｏＳ等のリチウムを含まない無機化合物も挙げられる。 Other positive electrode active materials capable of occluding and releasing lithium include lithium-free inorganic compounds such as MnO 2 , V 2 O 5 , V 6 O 13 , NiS, and MoS.
　リチウムを吸蔵および放出することが可能な正極活物質は、上記以外のものであってもよい。また、上記で例示した正極活物質は、任意の組み合わせで２種以上混合されてもよい。 The positive electrode active material capable of occluding and releasing lithium may be other than the above. In addition, two or more kinds of positive electrode active materials exemplified above may be mixed in any combination.
（バインダー）
　バインダーとしては、例えば、ポリフッ化ビニリデン、ポリテトラフルオロエチレン、ポリアクリロニトリル、スチレンブタジエンゴム、カルボキシメチルセルロース、およびこれら樹脂材料のうちの１種を主体とする共重合体等からなる群より選ばれる少なくとも１種を用いることができる。 (binder)
The binder is, for example, at least one selected from the group consisting of polyvinylidene fluoride, polytetrafluoroethylene, polyacrylonitrile, styrene butadiene rubber, carboxymethyl cellulose, and a copolymer mainly composed of one of these resin materials. Seeds can be used.
（導電剤）
　導電剤としては、例えば、黒鉛、炭素繊維、カーボンブラック、アセチレンブラック、ケッチェンブラック、カーボンナノチューブおよびグラフェン等からなる群より選ばれる少なくとも１種の炭素材料を用いることができる。なお、導電剤は導電性を有する材料であればよく、炭素材料に限定されるものではない。例えば、導電剤として金属材料または導電性高分子材料等を用いるようにしてもよい。また、導電剤の形状としては、例えば、粒状、鱗片状、中空状、針状または筒状等が挙げられるが、特にこれらの形状に限定されるものではない。 (Conducting agent)
As the conductive agent, for example, at least one carbon material selected from the group consisting of graphite, carbon fiber, carbon black, acetylene black, ketjen black, carbon nanotubes, graphene and the like can be used. The conductive agent may be any material having conductivity, and is not limited to the carbon material. For example, a metal material, a conductive polymer material, or the like may be used as the conductive agent. The shape of the conductive agent includes, for example, granular, scaly, hollow, needle-shaped, tubular, and the like, but is not particularly limited to these shapes.
（負極）
　負極２２は、内側面（第１の面）２２Ｓ１および外側面（第２の面）２２Ｓ２を有する負極集電体２２Ａと、負極集電体２２Ａの内側面２２Ｓ１に設けられた負極活物質層２２Ｂ１と、負極集電体２２Ａの外側面２２Ｓ２に設けられた負極活物質層２２Ｂ２とを備える。 (Negative electrode)
The negative electrode 22 includes a negative electrode current collector 22A having an inner side surface (first surface) 22S1 and an outer side surface (second surface) 22S2, and a negative electrode active material layer 22B1 provided on the inner side surface 22S1 of the negative electrode current collector 22A. And the negative electrode active material layer 22B2 provided on the outer surface 22S2 of the negative electrode current collector 22A.
　負極２２の中心側端部の内側面２２Ｓ１には、負極活物質層２２Ｂ１が設けられず、負極集電体２２Ａの内側面２２Ｓ１が露出した負極集電体露出部２２Ｃ１が設けられている。負極２２の中心側端部の外側面２２Ｓ２には、負極活物質層２２Ｂ２が設けられず、負極集電体２２Ａの外側面２２Ｓ２が露出した負極集電体露出部２２Ｃ２が設けられている。 The negative electrode active material layer 22B1 is not provided on the inner side surface 22S1 of the central end portion of the negative electrode 22, and the negative electrode current collector exposed portion 22C1 in which the inner side surface 22S1 of the negative electrode current collector 22A is exposed is provided. The negative electrode active material layer 22B2 is not provided on the outer surface 22S2 of the central end portion of the negative electrode 22, and the negative electrode current collector exposed portion 22C2 in which the outer surface 22S2 of the negative electrode current collector 22A is exposed is provided.
　負極集電体露出部２２Ｃ１上には補強金属層２４が設けられ、補強金属層２４上には負極タブ２７が設けられている。このように負極集電体露出部２２Ｃ１上に補強金属層２４および補強金属層２４が重ねて設けられていることで、補強金属層２４および負極タブ２７を一度の溶接により負極集電体２２Ａに取り付けることができる。また、負極タブ２７は補強金属層２４に包まれた状態となるため、負極タブ２７のカットバリ等による物理ショートの発生を抑制することができる。さらに、負極集電体露出部２２Ｃ１上に補強金属層２４および負極タブ２７が巻回方向に並べて設けられている場合に比べて、負極集電体２２Ａにシワが発生することを抑制することができる。 A reinforcing metal layer 24 is provided on the negative electrode current collector exposed portion 22C1, and a negative electrode tab 27 is provided on the reinforcing metal layer 24. By providing the reinforcing metal layer 24 and the reinforcing metal layer 24 on the negative electrode current collector exposed portion 22C1 in this way, the reinforcing metal layer 24 and the negative electrode tab 27 are welded to the negative electrode current collector 22A once. Can be attached. Further, since the negative electrode tab 27 is wrapped in the reinforcing metal layer 24, it is possible to suppress the occurrence of a physical short circuit due to cut burrs or the like of the negative electrode tab 27. Further, it is possible to suppress the occurrence of wrinkles in the negative electrode current collector 22A as compared with the case where the reinforcing metal layer 24 and the negative electrode tab 27 are provided side by side in the winding direction on the negative electrode current collector exposed portion 22C1. it can.
　補強金属層２４は、中心孔２０Ａを補強する。具体的には、補強金属層２４は、電池の充放電により電極体２０が膨張収縮される場合において、電極体２０の中心孔２０Ａの形状および大きさを保持する。補強金属層２４は、例えば、箔状または板状を有する。補強金属層２４は、負極集電体露出部２２Ｃ１と共に円筒状に巻回されている。 The reinforcing metal layer 24 reinforces the central hole 20A. Specifically, the reinforcing metal layer 24 retains the shape and size of the central hole 20A of the electrode body 20 when the electrode body 20 is expanded and contracted by charging and discharging the battery. The reinforcing metal layer 24 has, for example, a foil shape or a plate shape. The reinforcing metal layer 24 is wound in a cylindrical shape together with the negative electrode current collector exposed portion 22C1.
　ここで、補強金属層２４の作用効果の理解を容易にするため、図５を参照して、補強金属層２４が設けられていない電極体３０の問題点について説明する。電池の充放電により電極体３０が膨張収縮し、電極体３０の中心孔２０Ａに向けて圧力が生じた場合、電極体３０の中心孔２０Ａの形状および大きさが変化する。これに伴って、正極２１の巻回中心側の先端の内側に位置する負極２２が、正極２１の巻回中心側の先端２１Ｄに押されて、負極２２に座屈が発生する（図５中、領域２０Ｒ参照）。このような座屈が発生すると、セパレータ２３が破損し、正極２１と負極２２とがショートする場合がある。このようなショートが発生すると、電池の信頼性や安全性が低下する。 Here, in order to facilitate understanding of the action and effect of the reinforcing metal layer 24, the problem of the electrode body 30 in which the reinforcing metal layer 24 is not provided will be described with reference to FIG. When the electrode body 30 expands and contracts due to charging and discharging of the battery and pressure is generated toward the central hole 20A of the electrode body 30, the shape and size of the central hole 20A of the electrode body 30 changes. Along with this, the negative electrode 22 located inside the tip of the positive electrode 21 on the winding center side is pushed by the tip 21D of the positive electrode 21 on the winding center side, and buckling occurs in the negative electrode 22 (in FIG. 5). , See region 20R). When such buckling occurs, the separator 23 may be damaged and the positive electrode 21 and the negative electrode 22 may be short-circuited. When such a short circuit occurs, the reliability and safety of the battery are lowered.
　これに対して、第１の実施形態における電池では、電極体２０が、負極２２の巻回中心側の端部に負極集電体露出部２２Ｃ１と共に巻回された円筒状の補強金属層２４を有しているため、電極体２０の中心孔２０Ａの強度を向上させることができる。これにより、電池の充放電により電極体２０が膨張収縮し、電極体２０の中心孔２０Ａに向けて圧力が生じた場合、電極体２０の中心孔２０Ａの形状および大きさが変化することを抑制することができる。これにより、正極２１の巻回中心側の先端２１Ｄに負極２２の外側面が押されて、負極２２に座屈が発生すること抑制することができる（図２中、領域２０Ｒ参照）。したがって、正極２１と負極２２とのショートを抑制することができる。よって、電池の信頼性や安全性の低下を抑制することができる。 On the other hand, in the battery of the first embodiment, the electrode body 20 has a cylindrical reinforcing metal layer 24 wound around the end of the negative electrode 22 on the winding center side together with the negative electrode current collector exposed portion 22C1. Therefore, the strength of the central hole 20A of the electrode body 20 can be improved. As a result, when the electrode body 20 expands and contracts due to charging and discharging of the battery and pressure is generated toward the central hole 20A of the electrode body 20, the shape and size of the central hole 20A of the electrode body 20 are suppressed from changing. can do. As a result, the outer surface of the negative electrode 22 is pressed against the tip 21D on the winding center side of the positive electrode 21, and buckling can be suppressed from occurring in the negative electrode 22 (see region 20R in FIG. 2). Therefore, a short circuit between the positive electrode 21 and the negative electrode 22 can be suppressed. Therefore, it is possible to suppress a decrease in the reliability and safety of the battery.
　補強金属層２４は、銅、銅ニッケル合金、ニッケル、亜鉛、銅亜鉛合金または銅亜鉛ニッケル合金を含むことが好ましい。補強金属層２４がこのような材料を含むことで、充放電において、負極集電体２２Ａに接続された補強金属層２４が溶解することを抑制することができる。したがって、電池の信頼性の低下を抑制することができる。 The reinforcing metal layer 24 preferably contains copper, copper-nickel alloy, nickel, zinc, copper-zinc alloy or copper-zinc-nickel alloy. When the reinforcing metal layer 24 contains such a material, it is possible to prevent the reinforcing metal layer 24 connected to the negative electrode current collector 22A from being melted during charging and discharging. Therefore, it is possible to suppress a decrease in the reliability of the battery.
　補強金属層２４の厚さが、好ましくは２０μｍ以上１００μｍ以下、より好ましくは３０μｍ以上８０μｍ以下である。補強金属層２４の厚みが２０μｍ以上であると、円筒状に巻回された補強金属層２４の強度を十分に高めることができるので、電池の充放電により電極体２０が膨張収縮される場合において、電極体２０の中心孔２０Ａの形状および大きさが変化することを抑制することができる。したがって、電極体２０の巻回中心側において負極２２に座屈が発生すること抑制することができる。よって、電池の信頼性や安全性の低下を抑制することができる。一方、補強金属層２４の厚みが１００μｍ以下であると、補強金属層２４の巻回外周側の端部の段差の増大を抑制することができるため、この段差形状が、補強金属層２４よりも外周側に位置する正極２１および負極２２に転写されることを抑制することができる。したがって、正極２１および負極２２に歪みが発生することを抑制することができるので、電池の信頼性の低下を抑制することができる。また、補強金属層２４の厚みが１００μｍ以下であると、正極２１および負極２２の巻回数の低下を抑制することができるので、電池のエネルギー密度の低下を抑制することができる。 The thickness of the reinforcing metal layer 24 is preferably 20 μm or more and 100 μm or less, and more preferably 30 μm or more and 80 μm or less. When the thickness of the reinforcing metal layer 24 is 20 μm or more, the strength of the reinforcing metal layer 24 wound in a cylindrical shape can be sufficiently increased, so that when the electrode body 20 is expanded and contracted by charging and discharging the battery. , It is possible to suppress the change in the shape and size of the central hole 20A of the electrode body 20. Therefore, it is possible to prevent buckling from occurring in the negative electrode 22 on the winding center side of the electrode body 20. Therefore, it is possible to suppress a decrease in the reliability and safety of the battery. On the other hand, when the thickness of the reinforcing metal layer 24 is 100 μm or less, it is possible to suppress an increase in the step at the end of the reinforcing metal layer 24 on the winding outer peripheral side, so that the step shape is larger than that of the reinforcing metal layer 24. It is possible to suppress the transfer to the positive electrode 21 and the negative electrode 22 located on the outer peripheral side. Therefore, it is possible to suppress the occurrence of distortion in the positive electrode 21 and the negative electrode 22, and thus it is possible to suppress a decrease in the reliability of the battery. Further, when the thickness of the reinforcing metal layer 24 is 100 μm or less, the decrease in the number of turns of the positive electrode 21 and the negative electrode 22 can be suppressed, so that the decrease in the energy density of the battery can be suppressed.
　補強金属層２４の巻回数は、少なくとも１周以上、好ましくは１．２周以上３周以下、より好ましくは１．２周以上１．８周以下である。巻回数が１周未満であると、補強金属層２４を円筒状に巻回することができないため、負極２２に座屈が発生すること抑制する効果が大幅に低下する。巻回数が１．２周以上であると、円筒状に巻回された補強金属層２４の強度を十分に高めることができるので、電池の充放電により電極体２０が膨張収縮し、電極体２０の中心孔２０Ａに向けて圧力が生じた場合に、電極体２０の中心孔２０Ａの形状および大きさが変化することを抑制することができる。したがって、電極体２０の巻回中心側において負極２２に座屈が発生すること抑制することができる。よって、電池の信頼性や安全性の低下を抑制することができる。一方、巻回数が３周以下であると、正極２１および負極２２の巻回数の低下を抑制することができる。したがって、電池のエネルギー密度の低下を抑制することができる。 The number of turns of the reinforcing metal layer 24 is at least 1 lap or more, preferably 1.2 laps or more and 3 laps or less, and more preferably 1.2 laps or more and 1.8 laps or less. If the number of turns is less than one, the reinforcing metal layer 24 cannot be wound in a cylindrical shape, so that the effect of suppressing buckling of the negative electrode 22 is significantly reduced. When the number of turns is 1.2 or more, the strength of the reinforcing metal layer 24 wound in a cylindrical shape can be sufficiently increased, so that the electrode body 20 expands and contracts due to charging and discharging of the battery, and the electrode body 20 expands and contracts. It is possible to suppress a change in the shape and size of the central hole 20A of the electrode body 20 when a pressure is generated toward the central hole 20A of the electrode body 20. Therefore, it is possible to prevent buckling from occurring in the negative electrode 22 on the winding center side of the electrode body 20. Therefore, it is possible to suppress a decrease in the reliability and safety of the battery. On the other hand, when the number of turns is 3 or less, it is possible to suppress a decrease in the number of turns of the positive electrode 21 and the negative electrode 22. Therefore, it is possible to suppress a decrease in the energy density of the battery.
　負極２２の巻回外周側の端部の内側面２２Ｓ１には、負極活物質層２２Ｂ１が設けられず、負極集電体２２Ａの内側面２２Ｓ１が露出した負極集電体露出部２２Ｄ１が設けられている。負極２２の巻回外周側の端部の外側面２２Ｓ２には、負極活物質層２２Ｂ２が設けられず、負極集電体２２Ａの外側面２２Ｓ２が露出した負極集電体露出部２２Ｄ２が設けられている。負極集電体露出部２２Ｄ１または負極集電体露出部２２Ｄ２には、負極タブ２６が設けられている。但し、図２、図３では、負極集電体露出部２２Ｄ１に負極タブ２６が設けられた例が示されている。 The negative electrode active material layer 22B1 is not provided on the inner side surface 22S1 of the end on the winding outer peripheral side of the negative electrode 22, and the negative electrode current collector exposed portion 22D1 in which the inner side surface 22S1 of the negative electrode current collector 22A is exposed is provided. There is. The negative electrode active material layer 22B2 is not provided on the outer surface 22S2 of the end on the winding outer peripheral side of the negative electrode 22, and the negative electrode current collector exposed portion 22D2 in which the outer surface 22S2 of the negative electrode current collector 22A is exposed is provided. There is. The negative electrode current collector exposed portion 22D1 or the negative electrode current collector exposed portion 22D2 is provided with a negative electrode tab 26. However, FIGS. 2 and 3 show an example in which the negative electrode tab 26 is provided on the negative electrode current collector exposed portion 22D1.
　負極集電体２２Ａは、例えば、銅箔、ニッケル箔あるいはステンレス箔等の金属箔により構成されている。 The negative electrode current collector 22A is made of, for example, a metal foil such as a copper foil, a nickel foil, or a stainless steel foil.
　負極活物質層２２Ｂ１および負極活物質層２２Ｂ２は、リチウムを吸蔵および放出することが可能な負極活物質を含む。負極活物質層２２Ｂ１および負極活物質層２２Ｂ２は、必要に応じてバインダーおよび導電剤のうちの少なくとも１種をさらに含んでいてもよい。 The negative electrode active material layer 22B1 and the negative electrode active material layer 22B2 contain a negative electrode active material capable of storing and releasing lithium. The negative electrode active material layer 22B1 and the negative electrode active material layer 22B2 may further contain at least one of a binder and a conductive agent, if necessary.
　なお、この電池では、負極２２または負極活物質の電気化学当量が、正極２１の電気化学当量よりも大きくなっており、理論上、充電の途中において負極２２にリチウム金属が析出しないようになっていることが好ましい。 In this battery, the electrochemical equivalent of the negative electrode 22 or the negative electrode active material is larger than the electrochemical equivalent of the positive electrode 21, and theoretically, lithium metal does not precipitate on the negative electrode 22 during charging. It is preferable to have.
（負極活物質）
　負極活物質は、例えば、炭素含有材料を含む第１の負極活物質を含む。負極活物質は、ケイ素（Ｓｉ）含有材料を含む第２の負極活物質をさらに含むことが好ましい。負極活物質が第２の負極活物質をさらに含むことで、充放電時において負極２２の膨張収縮を抑制しながら、高い理論容量を得ることができる。 (Negative electrode active material)
The negative electrode active material includes, for example, a first negative electrode active material containing a carbon-containing material. The negative electrode active material preferably further contains a second negative electrode active material containing a silicon (Si) -containing material. By further containing the second negative electrode active material in the negative electrode active material, a high theoretical capacity can be obtained while suppressing the expansion and contraction of the negative electrode 22 during charging and discharging.
　負極活物質層２２Ｂ１中における第２の負極活物質の含有量および負極活物質層２２Ｂ２中における第２の負極活物質の含有量は、好ましくは５質量％以上２０質量％以下、より好ましくは１０質量％以上２０質量％以下である。第２の負極活物質の含有量が５質量％以上２０質量％以下であると、高い理論容量を得ることができると共に、電極体２０の巻回中心側において負極２２に座屈が発生することができる。 The content of the second negative electrode active material in the negative electrode active material layer 22B1 and the content of the second negative electrode active material in the negative electrode active material layer 22B2 are preferably 5% by mass or more and 20% by mass or less, more preferably 10. It is 0% by mass or more and 20% by mass or less. When the content of the second negative electrode active material is 5% by mass or more and 20% by mass or less, a high theoretical capacity can be obtained, and buckling occurs in the negative electrode 22 on the winding center side of the electrode body 20. Can be done.
　上記の第２の負極活物質の含有量は、以下のようにして求められる。まず、電池から負極２２を取り出し、ジメチルカーボネート（ＤＭＣ）で洗浄、乾燥させたのち、負極集電体２２Ａを取り除く。次に、数～数十ｍｇのサンプル（負極活物質層２２Ｂ１および負極活物質層２２Ｂ２）を示差熱天秤装置(ＴＧ－ＤＴＡ　例えば株式会社リガク製Rigaku Thermo plus TG8120)を用い、１～５℃／ｍｉｎの昇温速度で、空気雰囲気下にて加熱（例えば６００℃まで加熱）し、その際の重量減少量から、負極活物質層２２Ｂ１および負極活物質層２２Ｂ２に含まれる、第２の負極活物質以外の材料（例えば第１の負極活物質、バインダーおよび導電剤）の質量を求める。次に、“負極活物質層２２Ｂ１および負極活物質層２２Ｂ２の全質量”から“第２の正極活物質以外の材料の質量”を差し引き、“第２の負極活物質の質量”を求める。次に、“負極活物質層２２Ｂ１および負極活物質層２２Ｂ２の全質量”に対する“第２の負極活物質の質量”の割合を百分率（質量％）として求める。 The content of the above-mentioned second negative electrode active material is determined as follows. First, the negative electrode 22 is taken out from the battery, washed with dimethyl carbonate (DMC) and dried, and then the negative electrode current collector 22A is removed. Next, a sample of several to several tens of mg (negative electrode active material layer 22B1 and negative electrode active material layer 22B2) was used with a differential heat balance device (TG-DTA, for example, Rigaku Thermo plus TG8120 manufactured by Rigaku Co., Ltd.) at 1 to 5 ° C./ The second negative electrode activity contained in the negative electrode active material layer 22B1 and the negative electrode active material layer 22B2 is determined by the amount of weight loss at that time when heating is performed in an air atmosphere (for example, heating to 600 ° C.) at a heating rate of min. The mass of a material other than the substance (for example, the first negative electrode active material, the binder and the conductive agent) is determined. Next, the "mass of the material other than the second positive electrode active material" is subtracted from the "total mass of the negative electrode active material layer 22B1 and the negative electrode active material layer 22B2" to obtain the "mass of the second negative electrode active material". Next, the ratio of the "mass of the second negative electrode active material" to the "total mass of the negative electrode active material layer 22B1 and the negative electrode active material layer 22B2" is determined as a percentage (mass%).
（第１の負極活物質）
　第１の負極活物質は、上述のように、炭素含有材料を含む。本明細書において、炭素含有材料とは、炭素を構成元素として含む材料の総称を意味する。但し、炭素含有材料は、炭素だけを構成元素として含んでいてもよい。なお、炭素含有材料の種類は、１種類だけでもよいし、２種類以上でもよい。 (First negative electrode active material)
The first negative electrode active material contains a carbon-containing material as described above. In the present specification, the carbon-containing material means a general term for materials containing carbon as a constituent element. However, the carbon-containing material may contain only carbon as a constituent element. The type of carbon-containing material may be only one type or two or more types.
　第１の負極活物質が炭素含有材料を含むことにより、炭素含有材料の結晶構造がリチウムの吸蔵放出時においてほとんど変化しないと共に、その炭素含有材料が導電剤としても機能する。これにより、高いエネルギー密度を安定に得ることができると共に、負極活物質層２２Ｂ１および負極活物質層２２Ｂ２の導電性を向上させることができる。 Since the first negative electrode active material contains a carbon-containing material, the crystal structure of the carbon-containing material hardly changes at the time of occlusion and release of lithium, and the carbon-containing material also functions as a conductive agent. As a result, a high energy density can be stably obtained, and the conductivity of the negative electrode active material layer 22B1 and the negative electrode active material layer 22B2 can be improved.
　具体的には、炭素含有材料は、例えば、易黒鉛化性炭素、難黒鉛化性炭素および黒鉛等である。但し、難黒鉛化性炭素における（００２）面の面間隔は、例えば、０．３７ｎｍ以上であると共に、黒鉛における（００２）面の面間隔は、例えば、０．３４ｎｍ以下である。 Specifically, the carbon-containing material is, for example, graphitizable carbon, non-graphitizable carbon, graphite, and the like. However, the interplanar spacing of the (002) plane in graphitizable carbon is, for example, 0.37 nm or more, and the interplanar spacing of the (002) plane in graphite is, for example, 0.34 nm or less.
　より具体的には、炭素含有材料は、例えば、熱分解炭素類、コークス類、ガラス状炭素繊維、有機高分子化合物焼成体、活性炭およびカーボンブラック類等である。このコークス類は、例えば、ピッチコークス、ニードルコークスおよび石油コークス等を含む。有機高分子化合物焼成体は、フェノール樹脂およびフラン樹脂等の高分子化合物が任意の温度で焼成（炭素化）された焼成物である。この他、炭素含有材料は、例えば、約１０００℃以下の温度で熱処理された低結晶性炭素でもよいし、非晶質炭素でもよい。 More specifically, the carbon-containing material is, for example, pyrolytic carbons, cokes, glassy carbon fibers, calcined organic polymer compound, activated carbon, carbon blacks, and the like. These cokes include, for example, pitch coke, needle coke, petroleum coke and the like. The fired organic polymer compound is a fired product obtained by firing (carbonizing) a polymer compound such as a phenol resin and a furan resin at an arbitrary temperature. In addition, the carbon-containing material may be, for example, low crystalline carbon heat-treated at a temperature of about 1000 ° C. or lower, or amorphous carbon.
　第１の負極活物質の形状は、特に限定されないが、例えば、繊維状、球状（粒子状）および鱗片状等である。２種類以上の形状を有する複数の第１の負極活物質が混在していてもよい。 The shape of the first negative electrode active material is not particularly limited, but is, for example, fibrous, spherical (particulate), scaly, or the like. A plurality of first negative electrode active materials having two or more types of shapes may be mixed.
（第２の負極活物質）
　第２の負極活物質は、上述のように、ケイ素含有材料を含む。本明細書において、ケイ素含有材料とは、ケイ素を構成元素として含む材料の総称を意味する。但し、ケイ素含有材料は、ケイ素だけを構成元素として含んでいてもよい。なお、ケイ素含有材料の種類は、１種類だけでもよいし、２種類以上でもよい。 (Second negative electrode active material)
The second negative electrode active material contains a silicon-containing material as described above. In the present specification, the silicon-containing material means a general term for materials containing silicon as a constituent element. However, the silicon-containing material may contain only silicon as a constituent element. The type of silicon-containing material may be only one type or two or more types.
　ケイ含有材料は、リチウムと合金を形成可能であり、ケイ素の単体でもよいし、ケイ素の合金でもよいし、ケイ素の化合物でもよいし、それらの２種類以上の混合物でもよいし、それらの１種類または２種類以上の相を含む材料でもよい。また、ケイ素含有材料は、結晶質でもよいし、非晶質（アモルファス）でもよいし、結晶質部分および非晶質部分の双方を含んでいてもよい。但し、ここで説明した単体は、あくまで一般的な単体を意味しているため、微量の不純物を含んでいてもよい。すなわち、単体の純度は、必ずしも１００％に限られない。 The Kay-containing material can form an alloy with lithium, and may be a simple substance of silicon, an alloy of silicon, a compound of silicon, a mixture of two or more of them, or one of them. Alternatively, a material containing two or more kinds of phases may be used. Further, the silicon-containing material may be crystalline, amorphous, or may contain both a crystalline portion and an amorphous portion. However, since the simple substance described here means a general simple substance to the last, it may contain a trace amount of impurities. That is, the purity of a simple substance is not necessarily limited to 100%.
　ケイ素の合金は、例えば、ケイ素以外の構成元素として、スズ、ニッケル、銅、鉄、コバルト、マンガン、亜鉛、インジウム（Ｉｎ）、銀（Ａｇ）、チタン、ゲルマニウム（Ｇｅ）、ビスマス（Ｂｉ）、アンチモン（Ｓｂ）およびクロム等のうちのいずれか１種類または２種類以上を含む。ケイ素の化合物は、例えば、ケイ素以外の構成元素として、炭素および酸素等のうちのいずれか１種類または２種類以上を含む。なお、ケイ素の化合物は、例えば、ケイ素以外の構成元素として、ケイ素の合金に関して説明した一連の構成元素のうちのいずれか１種類または２種類以上を含んでいてもよい。 Silicon alloys include, for example, tin, nickel, copper, iron, cobalt, manganese, zinc, indium (In), silver (Ag), titanium, germanium (Ge), bismuth (Bi), as constituent elements other than silicon. Includes any one or more of antimony (Sb), chromium and the like. The silicon compound contains, for example, any one or more of carbon, oxygen, and the like as constituent elements other than silicon. The silicon compound may contain, for example, any one or more of the series of constituent elements described for the silicon alloy as constituent elements other than silicon.
　具体的には、ケイ素の合金およびケイ素の化合物は、例えば、ＳｉＢ４、ＳｉＢ６、Ｍｇ２Ｓｉ、Ｎｉ２Ｓｉ、ＴｉＳｉ２、ＭｏＳｉ２、ＣｏＳｉ２、ＮｉＳｉ２、ＣａＳｉ２、ＣｒＳｉ２、Ｃｕ５Ｓｉ、ＦｅＳｉ２、ＭｎＳｉ２、ＮｂＳｉ２、ＴａＳｉ２、ＶＳｉ２、ＷＳｉ２、ＺｎＳｉ２、ＳｉＣ、Ｓｉ３Ｎ４、Ｓｉ２Ｎ２ＯおよびＳｉＯｖ（０＜ｖ≦２）等である。但し、ｖの範囲は、任意に設定可能であり、例えば、０．２＜ｖ＜１．４でもよい。 Specifically, the silicon alloy and the silicon compound are, for example, SiB 4 , SiB 6 , Mg 2 Si, Ni 2 Si, TiSi 2 , MoSi 2 , CoSi 2 , NiSi 2 , CaSi 2 , CrSi 2 , Cu 5 Si, FeSi 2 , MnSi 2 , NbSi 2 , TaSi 2 , VSi 2 , WSi 2 , ZnSi 2 , SiC, Si 3 N 4 , Si 2 N 2 O, SiO v (0 <v ≦ 2) and the like. However, the range of v can be arbitrarily set, and may be, for example, 0.2 <v <1.4.
（他の負極活物質）
　なお、負極活物質は、例えば、上述した第１の負極活物質と共に、または上述した第１の負極活物質および第２の負極活物質と共に、他の負極活物質のうちのいずれか１種類または２種類以上を含んでいてもよい。 (Other negative electrode active materials)
The negative electrode active material may be, for example, any one of the other negative electrode active materials together with the above-mentioned first negative electrode active material, or with the above-mentioned first negative electrode active material and the second negative electrode active material. Two or more types may be included.
　他の負極活物質は、例えば、金属系材料であり、その金属系材料は、金属元素および半金属元素のうちのいずれか１種類または２種類以上を構成元素として含む材料の総称である。他の負極活物質が金属材料を含むことで、高いエネルギー密度が得られる。 The other negative electrode active material is, for example, a metal-based material, and the metal-based material is a general term for materials containing any one or more of metal elements and metalloid elements as constituent elements. High energy density can be obtained by including the metal material in the other negative electrode active material.
　金属系材料は、単体でもよいし、合金でもよいし、化合物でもよいし、それらの２種類以上の混合物でもよいし、それらの１種類または２種類以上の相を含む材料でもよい。但し、合金には、２種類以上の金属元素からなる材料だけでなく、１種類または２種類以上の金属元素と１種類または２種類以上の半金属元素とを含む材料も含まれる。また、合金は、１種類または２種類以上の非金属元素を含んでいてもよい。金属系材料の組織は、例えば、固溶体、共晶（共融混合物）、金属間化合物およびそれらの２種類以上の共存物等である。 The metal-based material may be a simple substance, an alloy, a compound, a mixture of two or more kinds thereof, or a material containing one kind or two or more kinds of phases thereof. However, the alloy includes not only a material composed of two or more kinds of metal elements, but also a material containing one kind or two or more kinds of metal elements and one kind or two or more kinds of metalloid elements. Further, the alloy may contain one kind or two or more kinds of non-metal elements. The structure of the metal-based material is, for example, a solid solution, a eutectic (eutectic mixture), an intermetallic compound, and a coexistence of two or more of them.
　金属元素および半金属元素のそれぞれは、リチウムと合金を形成可能である。具体的には、金属元素および半金属元素は、例えば、マグネシウム、ホウ素、アルミニウム、ガリウム、インジウム、ゲルマニウム、スズ、鉛、ビスマス、カドミウム、銀、亜鉛、ハフニウム、ジルコニウム、イットリウム、パラジウムおよび白金等である。 Each of the metallic element and the metalloid element can form an alloy with lithium. Specifically, the metal elements and metalloid elements are, for example, magnesium, boron, aluminum, gallium, indium, germanium, tin, lead, bismuth, cadmium, silver, zinc, hafnium, zirconium, yttrium, palladium, platinum and the like. is there.
（バインダー）
　バインダーとしては、正極活物質層２１Ｂと同様のものを用いることができる。 (binder)
As the binder, the same binder as that of the positive electrode active material layer 21B can be used.
（導電剤）
　導電剤としては、正極活物質層２１Ｂと同様のものを用いることができる。 (Conducting agent)
As the conductive agent, the same one as that of the positive electrode active material layer 21B can be used.
（セパレータ）
　セパレータ２３は、正極２１と負極２２とを隔離し、両極の接触による電流の短絡を防止しつつ、リチウムイオンを通過させるものである。セパレータ２３は、例えば、ポリテトラフルオロエチレン、ポリオレフィン樹脂（ポリプロピレン（ＰＰ）あるいはポリエチレン（ＰＥ）等）、アクリル樹脂、スチレン樹脂、ポリエステル樹脂またはナイロン樹脂、または、これらの樹脂をブレンドした樹脂からなる多孔質膜によって構成されており、これらの２種以上の多孔質膜を積層した構造とされていてもよい。 (Separator)
The separator 23 separates the positive electrode 21 and the negative electrode 22 and allows lithium ions to pass through while preventing a short circuit of current due to contact between the two electrodes. The separator 23 is porous, for example, made of polytetrafluoroethylene, polyolefin resin (polypropylene (PP), polyethylene (PE), etc.), acrylic resin, styrene resin, polyester resin or nylon resin, or a resin blended with these resins. It is composed of a quality film, and may have a structure in which two or more of these porous films are laminated.
　中でも、ポリオレフィン製の多孔質膜は短絡防止効果に優れ、かつシャットダウン効果による電池の安全性向上を図ることができるので好ましい。特にポリエチレンは、１００℃以上１６０℃以下の範囲内においてシャットダウン効果を得ることができ、かつ電気化学的安定性にも優れているので、セパレータ２３を構成する材料として好ましい。その中でも、低密度ポリエチレン、高密度ポリエチレン、線状ポリエチレンは溶融温度が適当であり、入手が容易なので好適に用いられる。他にも、化学的安定性を備えた樹脂を、ポリエチレンあるいはポリプロピレンと共重合またはブレンド化した材料を用いることができる。あるいは、多孔質膜は、ポリプロピレン層と、ポリエチレン層と、ポリプロピレン層を順次に積層した３層以上の構造を有していてもよい。例えば、ＰＰ／ＰＥ／ＰＰの三層構造とし、ＰＰとＰＥの質量比［ｗｔ％］が、ＰＰ：ＰＥ＝６０：４０～７５：２５とすることが望ましい。あるいは、コストの観点から、ＰＰが１００ｗｔ％またはＰＥが１００ｗｔ％の単層基材とすることもできる。セパレータ２３の作製方法としては、湿式、乾式を問わない。 Among them, the porous film made of polyolefin is preferable because it has an excellent short-circuit prevention effect and can improve the safety of the battery by the shutdown effect. In particular, polyethylene is preferable as a material constituting the separator 23 because it can obtain a shutdown effect in the range of 100 ° C. or higher and 160 ° C. or lower and is also excellent in electrochemical stability. Among them, low-density polyethylene, high-density polyethylene, and linear polyethylene are preferably used because they have an appropriate melting temperature and are easily available. In addition, a material obtained by copolymerizing or blending a resin having chemical stability with polyethylene or polypropylene can be used. Alternatively, the porous film may have a structure of three or more layers in which a polypropylene layer, a polyethylene layer, and a polypropylene layer are sequentially laminated. For example, it is desirable to have a three-layer structure of PP / PE / PP and have a mass ratio [wt%] of PP to PE of PP: PE = 60: 40 to 75:25. Alternatively, from the viewpoint of cost, a single-layer base material having 100 wt% PP or 100 wt% PE can be used. The method for producing the separator 23 may be wet or dry.
　セパレータ２３としては、不織布を用いてもよい。不織布を構成する繊維としては、アラミド繊維、ガラス繊維、ポリオレフィン繊維、ポリエチレンテレフタレート（ＰＥＴ）繊維、またはナイロン繊維等を用いることができる。また、これら２種以上の繊維を混合して不織布としてもよい。 A non-woven fabric may be used as the separator 23. As the fiber constituting the non-woven fabric, aramid fiber, glass fiber, polyolefin fiber, polyethylene terephthalate (PET) fiber, nylon fiber and the like can be used. Further, these two or more kinds of fibers may be mixed to form a non-woven fabric.
　セパレータ２３は、基材と、基材の片面または両面に設けられた表面層を備える構成を有していてもよい。表面層は、電気的な絶縁性を有する無機粒子と、無機粒子を基材の表面に結着すると共に、無機粒子同士を結着する樹脂材料とを含む。この樹脂材料は、例えば、フィブリル化し、複数のフィブリルが繋がった三次元的なネットワーク構造を有していてもよい。無機粒子は、この三次元的なネットワーク構造を有する樹脂材料に担持されている。また、樹脂材料はフィブリル化せずに基材の表面や無機粒子同士を結着してもよい。この場合、より高い結着性を得ることができる。上述のように基材の片面または両面に表面層を設けることで、セパレータ２３の耐酸化性、耐熱性および機械強度を高めることができる。 The separator 23 may have a structure including a base material and a surface layer provided on one side or both sides of the base material. The surface layer contains inorganic particles having an electrically insulating property, and a resin material that binds the inorganic particles to the surface of the base material and also binds the inorganic particles to each other. This resin material may have, for example, a three-dimensional network structure in which fibrils are formed and a plurality of fibrils are connected. The inorganic particles are supported on a resin material having this three-dimensional network structure. Further, the resin material may bind the surface of the base material or the inorganic particles to each other without becoming fibril. In this case, higher binding properties can be obtained. By providing the surface layer on one side or both sides of the base material as described above, the oxidation resistance, heat resistance and mechanical strength of the separator 23 can be improved.
　基材は、リチウムイオンを透過し、所定の機械的強度を有する絶縁性の膜から構成される多孔質膜であり、基材の空孔には電解液が保持されるため、電解液に対する耐性が高く、反応性が低く、膨張しにくいという特性を要することが好ましい。 The base material is a porous membrane composed of an insulating membrane that allows lithium ions to permeate and has a predetermined mechanical strength. Since the electrolytic solution is held in the pores of the base material, it is resistant to the electrolytic solution. It is preferable that the properties are high, the reactivity is low, and the swelling is difficult.
　基材を構成する材料としては、上述したセパレータ２３を構成する樹脂材料や不織布を用いることができる。 As the material constituting the base material, the resin material or the non-woven fabric constituting the separator 23 described above can be used.
　無機粒子は、金属酸化物、金属窒化物、金属炭化物および金属硫化物等の少なくとも１種を含む。金属酸化物としては、酸化アルミニウム（アルミナ、Ａｌ２Ｏ３）、ベーマイト（水和アルミニウム酸化物）、酸化マグネシウム（マグネシア、ＭｇＯ）、酸化チタン（チタニア、ＴｉＯ２）、酸化ジルコニウム（ジルコニア、ＺｒＯ２）、酸化ケイ素（シリカ、ＳｉＯ２）または酸化イットリウム（イットリア、Ｙ２Ｏ３）等を好適に用いることができる。金属窒化物としては、窒化ケイ素（Ｓｉ３Ｎ４）、窒化アルミニウム（ＡｌＮ）、窒化硼素（ＢＮ）または窒化チタン（ＴｉＮ）等を好適に用いることができる。金属炭化物としては、炭化ケイ素（ＳｉＣ）または炭化ホウ素（Ｂ４Ｃ）等を好適に用いることができる。金属硫化物としては、硫酸バリウム（ＢａＳＯ４）等を好適に用いることができる。また、ゼオライト（Ｍ２／ｎＯ・Ａｌ２Ｏ３・ｘＳｉＯ２・ｙＨ２Ｏ、Ｍは金属元素、ｘ≧２、ｙ≧０）等の多孔質アルミノケイ酸塩、層状ケイ酸塩、チタン酸バリウム（ＢａＴｉＯ３）またはチタン酸ストロンチウム（ＳｒＴｉＯ３）等の鉱物を用いてもよい。中でも、アルミナ、チタニア（特にルチル型構造を有するもの）、シリカまたはマグネシアを用いることが好ましく、アルミナを用いることがより好ましい。無機粒子は耐酸化性および耐熱性を備えており、無機粒子を含有する正極対向側面の表面層は、充電時の正極近傍における酸化環境に対しても強い耐性を有する。無機粒子の形状は特に限定されるものではなく、球状、板状、繊維状、キュービック状およびランダム形状等のいずれも用いることができる。 Inorganic particles include at least one such as metal oxides, metal nitrides, metal carbides and metal sulfides. Examples of metal oxides include aluminum oxide (alumina, Al 2 O 3 ), boehmite (hydrated aluminum oxide), magnesium oxide (magnesia, MgO), titanium oxide (titania, TiO 2 ), zirconium oxide (zirconia, ZrO 2). ), silicon oxide (silica, SiO 2) or yttrium oxide (yttria, Y 2 O 3) or the like can be suitably used. As the metal nitride, silicon nitride (Si 3 N 4 ), aluminum nitride (AlN), boron nitride (BN), titanium nitride (TiN) and the like can be preferably used. The metal carbide may be used silicon carbide (SiC) or boron carbide (B 4 C) or the like suitably. As the metal sulfide, barium sulfate (BaSO 4 ) or the like can be preferably used. In addition, porous aluminosilicates such as zeolite (M 2 / n O, Al 2 O 3 , xSiO 2 , yH 2 O, M is a metal element, x ≧ 2, y ≧ 0), layered silicate, and barium titanate. Minerals such as barium (BaTIO 3 ) or strontium titanate (SrTiO 3 ) may be used. Among them, alumina, titania (particularly those having a rutile type structure), silica or magnesia are preferably used, and alumina is more preferable. The inorganic particles have oxidation resistance and heat resistance, and the surface layer on the side surface facing the positive electrode containing the inorganic particles has strong resistance to the oxidizing environment in the vicinity of the positive electrode during charging. The shape of the inorganic particles is not particularly limited, and any of spherical, plate-like, fibrous, cubic, random and the like can be used.
　無機粒子の粒径は、１ｎｍ以上１０μｍ以下の範囲内であることが好ましい。粒径が１ｎｍ未満であると、無機粒子の入手が困難である。一方、粒径が１０μｍを超えると、電極間距離が大きくなり、限られたスペースで活物質充填量が十分得られず、電池容量が低下する。 The particle size of the inorganic particles is preferably in the range of 1 nm or more and 10 μm or less. If the particle size is less than 1 nm, it is difficult to obtain inorganic particles. On the other hand, if the particle size exceeds 10 μm, the distance between the electrodes becomes large, the amount of active material filled cannot be sufficiently obtained in a limited space, and the battery capacity decreases.
　表面層を構成する樹脂材料としては、ポリフッ化ビニリデン、ポリテトラフルオロエチレン等の含フッ素樹脂、フッ化ビニリデン－テトラフルオロエチレン共重合体、エチレン－テトラフルオロエチレン共重合体等の含フッ素ゴム、スチレン－ブタジエン共重合体またはその水素化物、アクリロニトリル－ブタジエン共重合体またはその水素化物、アクリロニトリル－ブタジエン－スチレン共重合体またはその水素化物、メタクリル酸エステル－アクリル酸エステル共重合体、スチレン－アクリル酸エステル共重合体、アクリロニトリル－アクリル酸エステル共重合体、エチレンプロピレンラバー、ポリビニルアルコール、ポリ酢酸ビニル等のゴム類、エチルセルロース、メチルセルロース、ヒドロキシエチルセルロース、カルボキシメチルセルロース等のセルロース誘導体、ポリフェニレンエーテル、ポリスルホン、ポリエーテルスルホン、ポリフェニレンスルフィド、ポリエーテルイミド、ポリイミド、全芳香族ポリアミド（アラミド）等のポリアミド、ポリアミドイミド、ポリアクリロニトリル、ポリビニルアルコール、ポリエーテル、アクリル酸樹脂またはポリエステル等の融点およびガラス転移温度の少なくとも一方が１８０℃以上の高い耐熱性を有する樹脂等が挙げられる。これら樹脂材料は、単独で用いてもよいし、２種以上を混合して用いてもよい。中でも、耐酸化性および柔軟性の観点からは、ポリフッ化ビニリデン等のフッ素系樹脂が好ましく、耐熱性の観点からは、アラミドまたはポリアミドイミドを含むことが好ましい。 Examples of the resin material constituting the surface layer include fluororesins such as polyvinylidene fluoride and polytetrafluoroethylene, fluororubber containing vinylidene fluoride-tetrafluoroethylene copolymer, ethylene-tetrafluoroethylene copolymer and the like, and styrene. -Butadiene copolymer or hydride thereof, acrylonitrile-butadiene copolymer or hydride thereof, acrylonitrile-butadiene-styrene copolymer or hydride thereof, methacrylic acid ester-acrylic acid ester copolymer, styrene-acrylic acid ester Copolymers, acrylonitrile-acrylic acid ester copolymers, rubbers such as ethylene propylene rubber, polyvinyl alcohol, vinyl acetate, cellulose derivatives such as ethyl cellulose, methyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, polyphenylene ether, polysulfone, polyether sulfone , Polyphenylene sulfide, polyetherimide, polyimide, polyamide such as total aromatic polyamide (aramid), polyamideimide, polyacrylonitrile, polyvinyl alcohol, polyether, acrylic acid resin or polyester, etc., at least one of the melting point and the glass transition temperature is 180. Examples thereof include resins having high heat resistance of ° C. or higher. These resin materials may be used alone or in combination of two or more. Among them, a fluorine-based resin such as polyvinylidene fluoride is preferable from the viewpoint of oxidation resistance and flexibility, and aramid or polyamide-imide is preferably contained from the viewpoint of heat resistance.
　表面層の形成方法としては、例えば、マトリックス樹脂、溶媒および無機物からなるスラリーを基材（多孔質膜）上に塗布し、マトリックス樹脂の貧溶媒且つ上記溶媒の親溶媒浴中を通過させて相分離させ、その後、乾燥させる方法を用いることができる。 As a method for forming the surface layer, for example, a slurry composed of a matrix resin, a solvent and an inorganic substance is applied onto a base material (porous film), and the matrix resin is passed through a poor solvent and a parent solvent bath of the above solvent to form a phase. A method of separating and then drying can be used.
　なお、上述した無機粒子は、基材としての多孔質膜に含有されていてもよい。また、表面層が無機粒子を含まず、樹脂材料のみにより構成されていてもよい。 The above-mentioned inorganic particles may be contained in a porous membrane as a base material. Further, the surface layer may not contain inorganic particles and may be composed only of a resin material.
（電解液）
　電解液は、いわゆる非水電解液であり、有機溶媒（非水溶媒）と、この有機溶媒に溶解された電解質塩とを含む。電解液が、電池特性を向上させるために、公知の添加剤を含んでいてもよい。なお、電解液に代えて、電解液と、この電解液を保持する保持体となる高分子化合物とを含む電解質層を用いるようにしてもよい。この場合、電解質層は、ゲル状となっていてもよい。 (Electrolytic solution)
The electrolytic solution is a so-called non-aqueous electrolytic solution, and contains an organic solvent (non-aqueous solvent) and an electrolyte salt dissolved in the organic solvent. The electrolyte may contain known additives to improve battery characteristics. In addition, instead of the electrolytic solution, an electrolyte layer containing an electrolytic solution and a polymer compound serving as a retainer for holding the electrolytic solution may be used. In this case, the electrolyte layer may be in the form of a gel.
　有機溶媒としては、炭酸エチレンまたは炭酸プロピレン等の環状の炭酸エステルを用いることができ、炭酸エチレンおよび炭酸プロピレンのうちの一方、特に両方を混合して用いることが好ましい。サイクル特性をさらに向上させることができるからである。 As the organic solvent, a cyclic carbonate ester such as ethylene carbonate or propylene carbonate can be used, and it is preferable to use one of ethylene carbonate and propylene carbonate, particularly both. This is because the cycle characteristics can be further improved.
　有機溶媒としては、また、これらの環状の炭酸エステルに加えて、炭酸ジエチル、炭酸ジメチル、炭酸エチルメチルまたは炭酸メチルプロピル等の鎖状の炭酸エステルを混合して用いることが好ましい。高いイオン伝導性を得ることができるからである。 As the organic solvent, in addition to these cyclic carbonate esters, it is preferable to mix and use a chain carbonate ester such as diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate or methyl propyl carbonate. This is because high ionic conductivity can be obtained.
　有機溶媒としては、さらにまた、２，４－ジフルオロアニソールまたは炭酸ビニレンを含むこと好ましい。２，４－ジフルオロアニソールは放電容量をさらに向上させることができ、また、炭酸ビニレンはサイクル特性をさらに向上させることができるからである。よって、これらを混合して用いれば、放電容量およびサイクル特性をさらに向上させることができるので好ましい。 As the organic solvent, it is preferable to further contain 2,4-difluoroanisole or vinylene carbonate. This is because 2,4-difluoroanisole can further improve the discharge capacity, and vinylene carbonate can further improve the cycle characteristics. Therefore, it is preferable to mix and use these because the discharge capacity and the cycle characteristics can be further improved.
　これらの他にも、有機溶媒としては、炭酸ブチレン、γ－ブチロラクトン、γ－バレロラクトン、１，２－ジメトキシエタン、テトラヒドロフラン、２－メチルテトラヒドロフラン、１，３－ジオキソラン、４－メチル－１，３－ジオキソラン、酢酸メチル、プロピオン酸メチル、アセトニトリル、グルタロニトリル、アジポニトリル、メトキシアセトニトリル、３－メトキシプロピロニトリル、Ｎ，Ｎ－ジメチルフォルムアミド、Ｎ－メチルピロリジノン、Ｎ－メチルオキサゾリジノン、Ｎ，Ｎ－ジメチルイミダゾリジノン、ニトロメタン、ニトロエタン、スルホラン、ジメチルスルフォキシドまたはリン酸トリメチル等が挙げられる。 In addition to these, as organic solvents, butylene carbonate, γ-butyrolactone, γ-valerolactone, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyl tetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3 -Dioxolane, methyl acetate, methyl propionate, acetonitrile, glutaronitrile, adiponitrile, methoxynitrile, 3-methoxypropyronitrile, N, N-dimethylformamide, N-methylpyrrolidinone, N-methyloxazolidinone, N, N- Examples thereof include dimethylimidazolidinone, nitromethane, nitroethane, sulfolane, dimethylsulfoxide, trimethyl phosphate and the like.
　なお、これらの有機溶媒の少なくとも一部の水素をフッ素で置換した化合物は、組み合わせる電極の種類によっては、電極反応の可逆性を向上させることができる場合があるので、好ましい場合もある。 Note that a compound in which at least a part of hydrogen in these organic solvents is replaced with fluorine may be preferable because the reversibility of the electrode reaction may be improved depending on the type of electrode to be combined.
　電解質塩としては、例えばリチウム塩が挙げられ、１種を単独で用いてもよく、２種以上を混合して用いてもよい。リチウム塩としては、ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＡｓＦ６、ＬｉＣｌＯ４、ＬｉＢ（Ｃ６Ｈ５）４、ＬｉＣＨ３ＳＯ３、ＬｉＣＦ３ＳＯ３、ＬｉＮ（ＳＯ２ＣＦ３）２、ＬｉＣ（ＳＯ２ＣＦ３）３、ＬｉＡｌＣｌ４、ＬｉＳｉＦ６、ＬｉＣｌ、ジフルオロ［オキソラト－Ｏ，Ｏ'］ホウ酸リチウム、リチウムビスオキサレートボレート、またはＬｉＢｒ等が挙げられる。中でも、ＬｉＰＦ６は高いイオン伝導性を得ることができると共に、サイクル特性をさらに向上させることができるので好ましい。 Examples of the electrolyte salt include a lithium salt, and one type may be used alone, or two or more types may be mixed and used. Lithium salts include LiPF 6 , LiBF 4 , LiAsF 6 , LiClO 4 , LiB (C 6 H 5 ) 4 , LiCH 3 SO 3 , LiCF 3 SO 3 , LiN (SO 2 CF 3 ) 2 , LiC (SO 2 CF). 3 ) 3 , LiAlCl 4 , LiSiF 6 , LiCl, difluoro [oxorat-O, O'] lithium borate, lithium bisoxalate volate, LiBr and the like can be mentioned. Among them, LiPF 6 is preferable because it can obtain high ionic conductivity and further improve the cycle characteristics.
［正極電位］
　第１の実施形態に係る電池では、一対の正極２１および負極２２当たりの完全充電状態における開回路電圧（すなわち電池電圧）は、４．２５Ｖ未満でもよいが、好ましくは４．２５Ｖ以上、より好ましくは４．３Ｖ以上、さらにより好ましくは４．４Ｖ以上になるように設計されていてもよい。電池電圧を高くすることにより、高いエネルギー密度を得ることができる。一対の正極２１および負極２２当たりの完全充電状態における開回路電圧の上限値は、好ましくは６Ｖ以下、より好ましくは４．６Ｖ以下、さらにより好ましくは４．５Ｖ以下である。 [Positive potential]
In the battery according to the first embodiment, the open circuit voltage (that is, battery voltage) in the fully charged state per pair of positive electrode 21 and negative electrode 22 may be less than 4.25V, but is preferably 4.25V or more, more preferably. May be designed to be 4.3 V or higher, and even more preferably 4.4 V or higher. A high energy density can be obtained by increasing the battery voltage. The upper limit of the open circuit voltage per pair of positive electrode 21 and negative electrode 22 in the fully charged state is preferably 6 V or less, more preferably 4.6 V or less, and even more preferably 4.5 V or less.
［電池の動作］
　上述の構成を有する電池では、充電を行うと、例えば、正極活物質層２１Ｂからリチウムイオンが放出され、電解液を介して負極活物質層２２Ｂに吸蔵される。また、放電を行うと、例えば、負極活物質層２２Ｂからリチウムイオンが放出され、電解液を介して正極活物質層２１Ｂに吸蔵される。 [Battery operation]
In the battery having the above configuration, when charging is performed, for example, lithium ions are released from the positive electrode active material layer 21B and are occluded in the negative electrode active material layer 22B via the electrolytic solution. Further, when the electric discharge is performed, for example, lithium ions are released from the negative electrode active material layer 22B and are occluded in the positive electrode active material layer 21B via the electrolytic solution.
［電池の製造方法］
　次に、本発明の第１の実施形態に係る電池の製造方法の一例について説明する。 [Battery manufacturing method]
Next, an example of a method for manufacturing a battery according to the first embodiment of the present invention will be described.
　まず、例えば、正極活物質と、導電剤と、バインダーとを混合して正極合剤を調製し、この正極合剤をＮ－メチル－２－ピロリドン（ＮＭＰ）等の溶剤に分散させてペースト状の正極合剤スラリーを作製する。次に、この正極合剤スラリーを正極集電体２１Ａの両面に塗布し溶剤を乾燥させ、ロールプレス機等により圧縮成型することにより正極活物質層２１Ｂ１および正極活物質層２１Ｂ２を形成し、正極２１を形成する。この際、正極合剤スラリーの塗布位置を調整することで、正極２１に正極集電体露出部２１Ｃ１および正極集電体露出部２１Ｃ２を形成する。 First, for example, a positive electrode active material, a conductive agent, and a binder are mixed to prepare a positive electrode mixture, and this positive electrode mixture is dispersed in a solvent such as N-methyl-2-pyrrolidone (NMP) to form a paste. To prepare a positive electrode mixture slurry of. Next, this positive electrode mixture slurry is applied to both sides of the positive electrode current collector 21A, the solvent is dried, and compression molding is performed by a roll press or the like to form the positive electrode active material layer 21B1 and the positive electrode active material layer 21B2. 21 is formed. At this time, by adjusting the coating position of the positive electrode mixture slurry, the positive electrode current collector exposed portion 21C1 and the positive electrode current collector exposed portion 21C2 are formed on the positive electrode 21.
　また、例えば、負極活物質と、バインダーとを混合して負極合剤を調製し、この負極合剤をＮ－メチル－２－ピロリドン等の溶剤に分散させてペースト状の負極合剤スラリーを作製する。次に、この負極合剤スラリーを負極集電体２２Ａの両面に塗布し溶剤を乾燥させ、ロールプレス機等により圧縮成型することにより負極活物質層２２Ｂ１および負極活物質層２２Ｂ２を形成し、負極２２を作製する。この際、負極合剤スラリーの塗布位置を調整することで、負極２２に負極集電体露出部２２Ｃ１、負極集電体露出部２２Ｃ２、負極集電体露出部２２Ｄ１および負極集電体露出部２２Ｄ２を形成する。 Further, for example, a negative electrode active material and a binder are mixed to prepare a negative electrode mixture, and this negative electrode mixture is dispersed in a solvent such as N-methyl-2-pyrrolidone to prepare a paste-like negative electrode mixture slurry. To do. Next, this negative electrode mixture slurry is applied to both sides of the negative electrode current collector 22A, the solvent is dried, and compression molding is performed by a roll press or the like to form the negative electrode active material layer 22B1 and the negative electrode active material layer 22B2. 22 is made. At this time, by adjusting the coating position of the negative electrode mixture slurry, the negative electrode 22 has a negative electrode current collector exposed portion 22C1, a negative electrode current collector exposed portion 22C2, a negative electrode current collector exposed portion 22D1, and a negative electrode current collector exposed portion 22D2. To form.
　次に、正極集電体露出部２１Ｃ１に正極タブ２５を溶接等により取り付けると共に、負極集電体露出部２２Ｄ１に負極タブ２６を溶接等により取り付ける。次に、負極集電体露出部２２Ｃ１に補強金属層２８、負極タブ２７をこの順序で重ね合わせたのち、負極集電体露出部２２Ｃ１に補強金属層２８と負極タブ２７とを溶接により取り付ける。次に、正極２１と負極２２とをセパレータ２３を介して巻回する。次に、正極タブ２５の先端部を安全弁機構１５に溶接すると共に、負極タブ２６および負極タブ２７の先端部を電池缶１１に溶接して、巻回した正極２１および負極２２を一対の絶縁板１２、１３で挟み電池缶１１の内部に収納する。次に、正極２１および負極２２を電池缶１１の内部に収納したのち、電解液を電池缶１１の内部に注入し、セパレータ２３に含浸させる。次に、電池缶１１の開口端部に電池蓋１４、安全弁機構１５および熱感抵抗素子１６を封口ガスケット１７を介してかしめることにより固定する。これにより、図１に示した電池が得られる。 Next, the positive electrode tab 25 is attached to the positive electrode current collector exposed portion 21C1 by welding or the like, and the negative electrode tab 26 is attached to the negative electrode current collector exposed portion 22D1 by welding or the like. Next, the reinforcing metal layer 28 and the negative electrode tab 27 are superposed on the negative electrode current collector exposed portion 22C1 in this order, and then the reinforcing metal layer 28 and the negative electrode tab 27 are attached to the negative electrode current collector exposed portion 22C1 by welding. Next, the positive electrode 21 and the negative electrode 22 are wound around the separator 23. Next, the tip of the positive electrode tab 25 is welded to the safety valve mechanism 15, and the tips of the negative electrode tab 26 and the negative electrode tab 27 are welded to the battery can 11, and the wound positive electrode 21 and the negative electrode 22 are combined with a pair of insulating plates. It is sandwiched between 12 and 13 and stored inside the battery can 11. Next, the positive electrode 21 and the negative electrode 22 are housed inside the battery can 11, and then the electrolytic solution is injected into the battery can 11 to impregnate the separator 23. Next, the battery lid 14, the safety valve mechanism 15, and the heat-sensitive resistance element 16 are fixed to the open end of the battery can 11 by caulking via the sealing gasket 17. As a result, the battery shown in FIG. 1 is obtained.
［効果］
　上述したように、第１の実施形態に係る電池では、電極体２０が、負極２２の巻回中心側の端部に負極集電体露出部２２Ｃ１と共に巻回された円筒状の補強金属層２４を有している。これにより、電極体２０の中心孔２０Ａの強度を向上させることができるので、電池の充放電により電極体２０が膨張収縮し、電極体２０の中心孔２０Ａに向けて圧力が生じた場合に、電極体２０の中心孔２０Ａの形状および大きさが変化することを抑制することができる。したがって、電極体２０の巻回中心側において負極２２に座屈が発生すること抑制し、高温保存下や充放電サイクル時等において正極２１と負極２２とがショートすることを抑制することができる。よって、電池の信頼性や安全性の低下を抑制することができる。 [effect]
As described above, in the battery according to the first embodiment, the electrode body 20 is wound around the end of the negative electrode 22 on the winding center side together with the negative electrode current collector exposed portion 22C1 in a cylindrical reinforcing metal layer 24. have. As a result, the strength of the central hole 20A of the electrode body 20 can be improved. Therefore, when the electrode body 20 expands and contracts due to charging and discharging of the battery and pressure is generated toward the central hole 20A of the electrode body 20, when pressure is generated. It is possible to suppress changes in the shape and size of the central hole 20A of the electrode body 20. Therefore, it is possible to suppress the occurrence of buckling of the negative electrode 22 on the winding center side of the electrode body 20, and to prevent the positive electrode 21 and the negative electrode 22 from being short-circuited under high temperature storage or during a charge / discharge cycle. Therefore, it is possible to suppress a decrease in the reliability and safety of the battery.
　上述のように、電極体２０の中心孔２０Ａの形状および大きさが変化することを抑制することで、高温加熱試験や過負荷試験において、セル内圧開放弁の作動開放に伴い、電極体２０の収縮現象によって生じる正極２１および負極２２の断裂を抑制することができる。したがって、断裂した電極端同士の物理ショート蓄熱による不安全現象を抑制することができるため、安全性を向上させることができる。 As described above, by suppressing the change in the shape and size of the central hole 20A of the electrode body 20, in the high temperature heating test and the overload test, the electrode body 20 is operated and opened as the cell internal pressure release valve is opened. Rupture of the positive electrode 21 and the negative electrode 22 caused by the contraction phenomenon can be suppressed. Therefore, the unsafe phenomenon due to the physical short heat storage between the torn electrode ends can be suppressed, and the safety can be improved.
　電極体２０の巻回中心部は、負極集電体２２Ａを巻回した構造（すなわち同極同士が電極体２０の軽方向に隣接した構造）であるため、電極体２０の巻回中心部に絶縁テープを設けなくてもよくなる。また、負極タブ２７や補強金属層２４がカットバリを有している場合にも、電極体２０の巻回中心部でショートが発生することを抑制することができる。 Since the winding center of the electrode body 20 has a structure in which the negative electrode current collector 22A is wound (that is, the same electrodes are adjacent to each other in the light direction of the electrode body 20), the winding center of the electrode body 20 is located at the winding center. It is not necessary to provide an insulating tape. Further, even when the negative electrode tab 27 and the reinforcing metal layer 24 have cut burrs, it is possible to suppress the occurrence of a short circuit at the winding center of the electrode body 20.
　充電時のケイ素含有材料の膨張量は、炭素含有材料の膨張量よりも数倍大きいため、負極活物質層２２Ｂ１および負極活物質層２２Ｂ１中における第２の負極活物質の含有量が増加するに従って、充放時の電極体２０の膨張により、電極体２０の中心孔２０Ａに向けて作用する圧力が増大する。第１の実施形態に係る電池では、図３に示すように、円筒状の補強金属層２４により中心孔２０Ａが補強されているため、負極活物質層２２Ｂ１および負極活物質層２２Ｂ２中における第２の負極活物質の含有量が５質量％以上２０質量％以下の範囲でも、負極２２に座屈が発生することを抑制し、信頼性および安全性が低下することを抑制することができる。これに対して、図５に示すように、円筒状の補強金属層２４により中心孔２０Ａが補強されていない電池では、負極２２に座屈が発生し易くなり、信頼性および安全性の低下が顕著となる。 Since the expansion amount of the silicon-containing material during charging is several times larger than the expansion amount of the carbon-containing material, as the content of the second negative electrode active material in the negative electrode active material layer 22B1 and the negative electrode active material layer 22B1 increases, Due to the expansion of the electrode body 20 at the time of charging, the pressure acting toward the central hole 20A of the electrode body 20 increases. In the battery according to the first embodiment, as shown in FIG. 3, since the central hole 20A is reinforced by the cylindrical reinforcing metal layer 24, the second in the negative electrode active material layer 22B1 and the negative electrode active material layer 22B2. Even when the content of the negative electrode active material is in the range of 5% by mass or more and 20% by mass or less, it is possible to suppress the occurrence of buckling in the negative electrode 22 and suppress the deterioration of reliability and safety. On the other hand, as shown in FIG. 5, in a battery in which the central hole 20A is not reinforced by the cylindrical reinforcing metal layer 24, buckling is likely to occur in the negative electrode 22, which reduces reliability and safety. It becomes remarkable.
＜２　第２の実施形態＞
　第２の実施形態では、上述の第１の実施形態に係る電池を備える電子機器について説明する。 <2 Second embodiment>
In the second embodiment, the electronic device including the battery according to the first embodiment described above will be described.
　以下、図６を参照して、本発明の第２の実施形態に係る電子機器１００の構成の一例について説明する。電子機器１００は、電子機器本体の電子回路１１０と、電池パック１２０とを備える。電池パック１２０は、正極端子１２３ａおよび負極端子１２３ｂを介して電子回路１１０に対して電気的に接続されている。電子機器１００は、電池パック１２０を着脱自在な構成を有していてもよい。 Hereinafter, an example of the configuration of the electronic device 100 according to the second embodiment of the present invention will be described with reference to FIG. The electronic device 100 includes an electronic circuit 110 of the main body of the electronic device and a battery pack 120. The battery pack 120 is electrically connected to the electronic circuit 110 via the positive electrode terminal 123a and the negative electrode terminal 123b. The electronic device 100 may have a structure in which the battery pack 120 can be attached and detached.
　電子機器１００としては、例えば、ノート型パーソナルコンピュータ、タブレット型コンピュータ、携帯電話（例えばスマートフォン等）、携帯情報端末（Personal Digital Assistants：ＰＤＡ）、表示装置（ＬＣＤ（Liquid Crystal Display）、ＥＬ（Electro Luminescence）ディスプレイ、電子ペーパ等）、撮像装置（例えばデジタルスチルカメラ、デジタルビデオカメラ等）、オーディオ機器（例えばポータブルオーディオプレイヤー）、ゲーム機器、コードレスフォン子機、電子書籍、電子辞書、ラジオ、ヘッドホン、ナビゲーションシステム、メモリーカード、ペースメーカー、補聴器、電動工具、電気シェーバー、冷蔵庫、エアコン、テレビ、ステレオ、温水器、電子レンジ、食器洗い器、洗濯機、乾燥器、照明機器、玩具、医療機器、ロボット、ロードコンディショナーまたは信号機等が挙げられるが、これらに限定されるものでなない。 Examples of the electronic device 100 include a notebook personal computer, a tablet computer, a mobile phone (for example, a smartphone), a personal digital assistant (PDA), a display device (LCD (Liquid Crystal Display), and an EL (Electro Luminescence). ) Display, electronic paper, etc.), imaging device (for example, digital still camera, digital video camera, etc.), audio equipment (for example, portable audio player), game equipment, cordless phone handset, electronic book, electronic dictionary, radio, headphones, navigation System, memory card, pacemaker, hearing aid, power tool, electric shaver, refrigerator, air conditioner, TV, stereo, water heater, microwave oven, dishwasher, washing machine, dryer, lighting equipment, toys, medical equipment, robot, road conditioner Alternatively, a signal device and the like can be mentioned, but the present invention is not limited to these.
（電子回路）
　電子回路１１０は、例えば、ＣＰＵ（Central Processing Unit）、周辺ロジック部、インターフェース部および記憶部等を備え、電子機器１００の全体を制御する。 (Electronic circuit)
The electronic circuit 110 includes, for example, a CPU (Central Processing Unit), a peripheral logic unit, an interface unit, a storage unit, and the like, and controls the entire electronic device 100.
（電池パック）
　電池パック１２０は、組電池１２１と、充放電回路１２２とを備える。電池パック１２０が、必用に応じて組電池１２１および充放電回路１２２を収容する外装材（図示せず）をさらに備えるようにしてもよい。 (Battery pack)
The battery pack 120 includes an assembled battery 121 and a charge / discharge circuit 122. The battery pack 120 may further include an exterior material (not shown) that houses the assembled battery 121 and the charge / discharge circuit 122, if necessary.
　組電池１２１は、複数の二次電池１２１ａを直列および／または並列に接続して構成されている。複数の二次電池１２１ａは、例えばｎ並列ｍ直列（ｎ、ｍは正の整数）に接続される。なお、図６では、６つの二次電池１２１ａが２並列３直列（２Ｐ３Ｓ）に接続された例が示されている。二次電池１２１ａとしては、上述の第１の実施形態に係る電池が用いられる。 The assembled battery 121 is configured by connecting a plurality of secondary batteries 121a in series and / or in parallel. The plurality of secondary batteries 121a are connected, for example, in n parallel m series (n and m are positive integers). Note that FIG. 6 shows an example in which six secondary batteries 121a are connected in two parallels and three series (2P3S). As the secondary battery 121a, the battery according to the first embodiment described above is used.
　ここでは、電池パック１２０が、複数の二次電池１２１ａにより構成される組電池１２１を備える場合について説明するが、電池パック１２０が、組電池１２１に代えて１つの二次電池１２１ａを備える構成を採用してもよい。 Here, a case where the battery pack 120 includes an assembled battery 121 composed of a plurality of secondary batteries 121a will be described. However, the battery pack 120 includes one secondary battery 121a instead of the assembled battery 121. It may be adopted.
　充放電回路１２２は、組電池１２１の充放電を制御する制御部である。具体的には、充電時には、充放電回路１２２は、組電池１２１に対する充電を制御する。一方、放電時（すなわち電子機器１００の使用時）には、充放電回路１２２は、電子機器１００に対する放電を制御する。 The charge / discharge circuit 122 is a control unit that controls the charge / discharge of the assembled battery 121. Specifically, at the time of charging, the charging / discharging circuit 122 controls charging of the assembled battery 121. On the other hand, at the time of discharging (that is, when the electronic device 100 is used), the charging / discharging circuit 122 controls the discharging to the electronic device 100.
　外装材としては、例えば、金属、高分子樹脂またはこれらの複合材料等より構成されるケースを用いることができる。複合材料としては、例えば、金属層と高分子樹脂層とが積層された積層体が挙げられる。 As the exterior material, for example, a case made of a metal, a polymer resin, a composite material thereof, or the like can be used. Examples of the composite material include a laminate in which a metal layer and a polymer resin layer are laminated.
＜３　変形例＞
　以上、本発明の実施形態について具体的に説明したが、本発明は、上述の実施形態に限定されるものではなく、本発明の技術的思想に基づく各種の変形が可能である。 <3 Modification example>
Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments, and various modifications based on the technical idea of the present invention are possible.
　上述の実施形態において挙げた構成、方法、工程、形状、材料および数値等はあくまでも例に過ぎず、必要に応じてこれと異なる構成、方法、工程、形状、材料および数値等を用いてもよい。上述の実施形態の構成、方法、工程、形状、材料および数値等は、本発明の主旨を逸脱しない限り、互いに組み合わせることが可能である。 The configurations, methods, processes, shapes, materials, numerical values, etc. mentioned in the above-described embodiments are merely examples, and different configurations, methods, processes, shapes, materials, numerical values, etc. may be used as necessary. .. The configurations, methods, processes, shapes, materials, numerical values, etc. of the above-described embodiments can be combined with each other without departing from the gist of the present invention.
　上述の実施形態にて例示した化合物等の化学式は代表的なものであって、同じ化合物の一般名称であれば、記載された価数等に限定されない。上述の実施形態で段階的に記載された数値範囲において、ある段階の数値範囲の上限値または下限値は、他の段階の数値範囲の上限値または下限値に置き換えてもよい。上述の実施形態に例示した材料は、特に断らない限り、１種を単独でまたは２種以上を組み合わせて用いることができる。 The chemical formulas of the compounds exemplified in the above-described embodiments are typical, and the general names of the same compounds are not limited to the stated valences and the like. In the numerical range described stepwise in the above embodiment, the upper limit value or the lower limit value of the numerical range of one step may be replaced with the upper limit value or the lower limit value of the numerical range of another step. Unless otherwise specified, the materials exemplified in the above-described embodiments may be used alone or in combination of two or more.
　上述の第１の実施形態において、電極体２０が有する中心孔２０Ａにセンターピンが挿入されていてもよい。この場合にも、電極体２０が、負極２２の巻回中心側の端部に負極集電体露出部２２Ｃ１と共に巻回された円筒状の補強金属層２４を有していることで、電極体２０の巻回中心側において負極２２に座屈が発生することを抑制することができる。電極体２０の中心孔２０Ａにセンターピンを挿入するために、センターピンの外周面と中心孔２０Ａの壁面の間には、通常隙間がある。このため、電池が、補強金属層２４を有していない場合には、負極２２に座屈が発生する。 In the first embodiment described above, the center pin may be inserted into the center hole 20A of the electrode body 20. Also in this case, the electrode body 20 has a cylindrical reinforcing metal layer 24 wound together with the negative electrode current collector exposed portion 22C1 at the end portion of the negative electrode body 22 on the winding center side, so that the electrode body 20 is an electrode body. It is possible to suppress the occurrence of buckling of the negative electrode 22 on the winding center side of 20. In order to insert the center pin into the center hole 20A of the electrode body 20, there is usually a gap between the outer peripheral surface of the center pin and the wall surface of the center hole 20A. Therefore, when the battery does not have the reinforcing metal layer 24, buckling occurs in the negative electrode 22.
　上述の第１の実施形態では、負極集電体露出部２２Ｃ１上に補強金属層２４が設けられている場合について説明したが、負極集電体露出部２２Ｃ２上に補強金属層２４が設けられていてもよい。この場合、負極タブ２７は、補強金属層２４上に設けられていてもよいし、負極集電体露出部２２Ｃ２と補強金属層２４との間に設けられていてもよいし、負極集電体露出部２２Ｃ１上に設けられていてもよい。負極タブ２７が負極集電体露出部２２Ｃ１上に設けられる場合、負極タブ２７と補強金属層２４とが負極集電体２２Ａの厚み方向に重なり合っていることが好ましい。この場合、負極タブ２７および補強金属層２４を一度の溶接により負極集電体２２Ａに取り付けることができる。
　また、負極タブ２７が負極集電体露出部２２Ｃ１と補強金属層２４との間に設けられていてもよい。
　また、負極集電体露出部２２Ｃ１上に補強金属層２４と負極タブ２７とが巻回方向に並べて設けられていてもよいし、負極集電体露出部２２Ｃ２上に補強金属層２４と負極タブ２７とが巻回方向に並べて設けられていてもよい。 In the first embodiment described above, the case where the reinforcing metal layer 24 is provided on the negative electrode current collector exposed portion 22C1 has been described, but the reinforcing metal layer 24 is provided on the negative electrode current collector exposed portion 22C2. You may. In this case, the negative electrode tab 27 may be provided on the reinforcing metal layer 24, may be provided between the negative electrode current collector exposed portion 22C2 and the reinforcing metal layer 24, or the negative electrode current collector. It may be provided on the exposed portion 22C1. When the negative electrode tab 27 is provided on the negative electrode current collector exposed portion 22C1, it is preferable that the negative electrode tab 27 and the reinforcing metal layer 24 overlap in the thickness direction of the negative electrode current collector 22A. In this case, the negative electrode tab 27 and the reinforcing metal layer 24 can be attached to the negative electrode current collector 22A by one welding.
Further, the negative electrode tab 27 may be provided between the negative electrode current collector exposed portion 22C1 and the reinforcing metal layer 24.
Further, the reinforcing metal layer 24 and the negative electrode tab 27 may be provided side by side in the winding direction on the negative electrode current collector exposed portion 22C1, or the reinforcing metal layer 24 and the negative electrode tab 27 may be provided on the negative electrode current collector exposed portion 22C2. 27 and 27 may be provided side by side in the winding direction.
　以下、実施例により本発明を具体的に説明するが、本発明はこれらの実施例のみに限定されるものではない。 Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples.
［実施例１］
（正極の作製工程）
　正極を次のようにして作製した。まず、正極活物質としてリチウムニッケル複合酸化物（ＮＣＡ）９１質量部と、導電剤としてグラファイト６質量部と、バインダーとしてポリフッ化ビニリデン３質量部とを混合することにより正極合剤を得たのち、Ｎ－メチル－２－ピロリドンに分散させることにより、ペースト状の正極合剤スラリーを得た。次に、帯状のアルミニウム箔（１５μｍ厚）からなる正極集電体の両面に正極合剤スラリーを塗布して乾燥させたのち、ロールプレス機で圧縮成型することにより、正極活物質層を形成した。この際、正極の長手方向における中央部の両面に正極集電体露出部が形成されるように、正極合剤スラリーの塗布位置を調整した。次に、正極の長手方向の両端において、正極活物質層と正極集電体の先端が揃うように、正極の長手方向の両端をカットした。次に、巻回後に内側面側に位置する予定の正極集電体露出部に、アルミニウム製の正極タブを超音波溶接により取り付けた。次に、正極タブを覆うように正極集電体露出部に絶縁テープを貼り合わせた。 [Example 1]
(Positive electrode manufacturing process)
The positive electrode was prepared as follows. First, a positive electrode mixture was obtained by mixing 91 parts by mass of lithium nickel composite oxide (NCA) as a positive electrode active material, 6 parts by mass of graphite as a conductive agent, and 3 parts by mass of polyvinylidene fluoride as a binder. By dispersing in N-methyl-2-pyrrolidone, a paste-like positive electrode mixture slurry was obtained. Next, a positive electrode mixture slurry was applied to both sides of a positive electrode current collector made of strip-shaped aluminum foil (15 μm thick), dried, and then compression-molded with a roll press to form a positive electrode active material layer. .. At this time, the coating position of the positive electrode mixture slurry was adjusted so that the positive electrode current collector exposed portions were formed on both sides of the central portion in the longitudinal direction of the positive electrode. Next, both ends in the longitudinal direction of the positive electrode were cut so that the positive electrode active material layer and the tips of the positive electrode current collector were aligned at both ends in the longitudinal direction of the positive electrode. Next, an aluminum positive electrode tab was attached to the exposed portion of the positive electrode current collector to be located on the inner side surface side after winding by ultrasonic welding. Next, an insulating tape was attached to the exposed portion of the positive electrode current collector so as to cover the positive electrode tab.
（負極の作製工程）
　負極を次のようにして作製した。まず、負極活物質として人造黒鉛粉末９７質量部と、バインダーとしてポリフッ化ビニリデン３質量部とを混合して負極合剤を得たのち、Ｎ－メチル－２－ピロリドンに分散させることにより、ペースト状の負極合剤スラリーを得た。次に、帯状の銅箔（１５μｍ厚）からなる負極集電体の両面に負極合剤スラリーを塗布して乾燥させたのち、ロールプレス機で圧縮成型することにより、負極活物質層を形成した。この際、負極の長手方向の両端部の両面に負極集電体露出部が形成されるように、負極合剤スラリーの塗布位置を調整した。次に、巻回後に中心側端部の内側面に位置する予定の負極集電体露出部上に、補強金属層、ニッケル製の負極タブをこの順序で重ね合わせたのち、負極集電体露出部に補強金属層と負極タブを超音波溶接により取り付けた。また、巻回後に外周側端部の内側面に位置する予定の負極集電体露出部に、ニッケル製の負極タブを超音波溶接により取り付けた。なお、補強金属層としては、表１に示すように、１．６周巻回可能な長さで、負極集電体と同一の幅を有する、厚さ５０μｍの矩形状のＣｕ箔を用いた。 (Negative electrode manufacturing process)
The negative electrode was prepared as follows. First, 97 parts by mass of artificial graphite powder as a negative electrode active material and 3 parts by mass of polyvinylidene fluoride as a binder are mixed to obtain a negative electrode mixture, which is then dispersed in N-methyl-2-pyrrolidone to form a paste. Negative electrode mixture slurry was obtained. Next, a negative electrode mixture slurry was applied to both sides of a negative electrode current collector made of a strip-shaped copper foil (15 μm thick), dried, and then compression-molded with a roll press to form a negative electrode active material layer. .. At this time, the coating position of the negative electrode mixture slurry was adjusted so that the negative electrode current collector exposed portions were formed on both ends of the negative electrode in the longitudinal direction. Next, a reinforcing metal layer and a nickel negative electrode tab are superposed in this order on the negative electrode current collector exposed portion to be located on the inner side surface of the central end after winding, and then the negative electrode current collector is exposed. A reinforcing metal layer and a negative electrode tab were attached to the portion by ultrasonic welding. In addition, a nickel negative electrode tab was attached by ultrasonic welding to the exposed negative electrode current collector, which is to be located on the inner surface of the outer peripheral end after winding. As the reinforcing metal layer, as shown in Table 1, a rectangular Cu foil having a length of 1.6 turns and having the same width as the negative electrode current collector and a thickness of 50 μm was used. ..
（電池の組み立て工程）
　電池を次のようにして組み立てた。まず、上述のようにして得られた正極と負極とを厚さ１０μｍの微多孔性ポリエチレン二軸延伸フィルムよりなるセパレータを介して、負極、セパレータ、正極、セパレータの順に積層した。次に、補強金属層および負極タブが取り付けられた負極の一端側から巻き始め、多数回巻回することにより、発電素子として巻回型電極体を得た。 (Battery assembly process)
The batteries were assembled as follows. First, the positive electrode and the negative electrode obtained as described above were laminated in the order of the negative electrode, the separator, the positive electrode, and the separator via a separator made of a microporous polyethylene biaxially stretched film having a thickness of 10 μm. Next, winding was started from one end side of the negative electrode to which the reinforcing metal layer and the negative electrode tab were attached, and the winding was performed many times to obtain a wound electrode body as a power generation element.
　次に、電極体を一対の絶縁板で挟み、負極タブを電池缶に溶接すると共に、正極タブを安全弁機構に溶接して、電極体を電池缶の内部に収納した。次に、エチレンカーボネートとメチルエチルカーボネートとを１：１の体積比で混合した溶媒に、電解質塩としてＬｉＰＦ６を１ｍｏｌ／ｄｍ３の濃度になるように溶解して非水電解液を調製した。 Next, the electrode body was sandwiched between a pair of insulating plates, the negative electrode tab was welded to the battery can, and the positive electrode tab was welded to the safety valve mechanism, and the electrode body was housed inside the battery can. Next, a non-aqueous electrolyte solution was prepared by dissolving LiPF 6 as an electrolyte salt in a solvent in which ethylene carbonate and methyl ethyl carbonate were mixed at a volume ratio of 1: 1 so as to have a concentration of 1 mol / dm 3 .
　最後に、上述の電極体が収容された電池缶内に、電解液を注入したのち、絶縁封口ガスケットを介して電池缶をかしめることにより、安全弁、ＰＴＣ素子および電池蓋を固定し、外径（直径）１８ｍｍ、高さ６５ｍｍの円筒型の電池を得た。 Finally, after injecting the electrolytic solution into the battery can containing the above-mentioned electrode body, the safety valve, the PTC element and the battery lid are fixed by crimping the battery can through the insulating sealing gasket to fix the outer diameter. A cylindrical battery having a diameter of 18 mm and a height of 65 mm was obtained.
［実施例２］
　負極の作製工程において、負極活物質として人造黒鉛粉末８７質量部と、負極活物質としてケイ素含有材料（ＳｉＯ）１０質量部、バインダーとしてポリフッ化ビニリデン３質量部とを混合して負極合剤を得たこと以外は実施例１と同様にして電池を得た。 [Example 2]
In the process of manufacturing the negative electrode, 87 parts by mass of artificial graphite powder as the negative electrode active material, 10 parts by mass of the silicon-containing material (SiO) as the negative electrode active material, and 3 parts by mass of polyvinylidene polyvinylfluoride as the binder are mixed to obtain a negative electrode mixture. A battery was obtained in the same manner as in Example 1 except for the above.
［実施例３～６］
　負極の作製工程において、補強金属層として、表１に示すように、ＣｕＮｉ合金箔、Ｎｉ箔、ＣｕＺｎ合金箔、ＣｕＺｎＮｉ合金箔を用いたこと以外は実施例２と同様にして電池を得た。 [Examples 3 to 6]
As shown in Table 1, a battery was obtained in the same manner as in Example 2 except that CuNi alloy foil, Ni foil, CuZn alloy foil, and CuZnNi alloy foil were used as the reinforcing metal layer in the process of manufacturing the negative electrode.
［実施例７～１０］
　負極の作製工程において、補強金属層として、表１に示すように、１０μｍ、２０μｍ、１００μｍ、１１０μｍのＣｕ箔を用いたこと以外は実施例２と同様にして電池を得た。 [Examples 7 to 10]
As shown in Table 1, a battery was obtained in the same manner as in Example 2 except that 10 μm, 20 μm, 100 μm, and 110 μm Cu foils were used as the reinforcing metal layer in the process of manufacturing the negative electrode.
［実施例１１～１４］
　負極の作製工程において、補強金属層として、表１に示すように、１．１周、１．２周、２周、３周巻回可能な長さを有するＣｕ箔を用いたこと以外は実施例２と同様にして電池を得た。 [Examples 11 to 14]
In the process of manufacturing the negative electrode, as shown in Table 1, the reinforcing metal layer was carried out except that a Cu foil having a length capable of winding 1.1 turns, 1.2 turns, 2 turns and 3 turns was used. A battery was obtained in the same manner as in Example 2.
［実施例１５、１６］
　負極の作製工程において、補強金属層として、表１に示すように、２周、３周巻回可能な長さで、厚さ１００μｍの銅箔を用いたこと以外は実施例２と同様にして電池を得た。 [Examples 15 and 16]
In the process of manufacturing the negative electrode, as shown in Table 1, a copper foil having a length of two turns and three turns and a thickness of 100 μm was used as the reinforcing metal layer in the same manner as in Example 2. I got a battery.
［実施例１７］
　負極の作製工程において、負極活物質として人造黒鉛粉末９２質量部と、負極活物質としてケイ素含有材料（ＳｉＯ）５質量部、バインダーとしてポリフッ化ビニリデン３質量部とを混合して負極合剤を得た。また、補強金属層として、表１に示すように、１．２周巻回可能な長さで、厚さ２０μｍの銅箔を用いた。これら以外のことは実施例２と同様にして電池を得た。 [Example 17]
In the process of manufacturing the negative electrode, 92 parts by mass of artificial graphite powder as the negative electrode active material, 5 parts by mass of the silicon-containing material (SiO) as the negative electrode active material, and 3 parts by mass of polyvinylidene fluoride as the binder are mixed to obtain a negative electrode mixture. It was. Further, as the reinforcing metal layer, as shown in Table 1, a copper foil having a length of 1.2 turns and a thickness of 20 μm was used. A battery was obtained in the same manner as in Example 2 except for these matters.
［実施例１８］
　負極の作製工程において、負極活物質として人造黒鉛粉末７７質量部と、負極活物質としてケイ素含有材料（ＳｉＯ）２０質量部、バインダーとしてポリフッ化ビニリデン３質量部とを混合して負極合剤を得たこと以外は実施例１７と同様にして電池を得た。 [Example 18]
In the process of manufacturing the negative electrode, 77 parts by mass of artificial graphite powder as the negative electrode active material, 20 parts by mass of the silicon-containing material (SiO) as the negative electrode active material, and 3 parts by mass of polyvinylidene polyvinylfluoride as the binder are mixed to obtain a negative electrode mixture. A battery was obtained in the same manner as in Example 17 except for the above.
［実施例１９］
（正極の作製工程）
　正極を次のようにして作製した。まず、実施例１と同様にして、ペースト状の正極合剤スラリーを得た。次に、帯状のアルミニウム箔（１５μｍ厚）からなる正極集電体の両面に正極合剤スラリーを塗布して乾燥させたのち、ロールプレス機で圧縮成型することにより、正極活物質層を形成した。この際、正極の長手方向の一端部の両面に正極集電体露出部が形成されるように、正極合剤スラリーの塗布位置を調整した。次に、巻回後に中心側端部の内側面に位置する予定の正極集電体露出部上に、補強金属層、アルミニウム製の正極タブをこの順序で重ね合わせたのち、正極集電体露出部に補強金属層と正極タブを超音波溶接により取り付けた。なお、補強金属層としては、表１に示すように、１．６周巻回可能な長さで、正極集電体と同一の幅を有する、厚さ１００μｍの矩形状のＡｌ箔を用いた。 [Example 19]
(Positive electrode manufacturing process)
The positive electrode was prepared as follows. First, a paste-like positive electrode mixture slurry was obtained in the same manner as in Example 1. Next, a positive electrode mixture slurry was applied to both sides of a positive electrode current collector made of strip-shaped aluminum foil (15 μm thick), dried, and then compression-molded with a roll press to form a positive electrode active material layer. .. At this time, the application position of the positive electrode mixture slurry was adjusted so that exposed portions of the positive electrode current collector were formed on both sides of one end portion in the longitudinal direction of the positive electrode. Next, a reinforcing metal layer and an aluminum positive electrode tab are superposed in this order on the positive electrode current collector exposed portion to be located on the inner side surface of the central end after winding, and then the positive electrode current collector is exposed. A reinforcing metal layer and a positive electrode tab were attached to the portion by ultrasonic welding. As the reinforcing metal layer, as shown in Table 1, a rectangular Al foil having a length of 1.6 turns and having the same width as the positive electrode current collector and a thickness of 100 μm was used. ..
（負極の作製工程）
　負極を次のようにして作製した。まず、実施例１と同様にして、ペースト状の負極合剤スラリーを得た。次に、帯状の銅箔（１５μｍ厚）からなる負極集電体の両面に負極合剤スラリーを塗布して乾燥させたのち、ロールプレス機で圧縮成型することにより、負極活物質層を形成した。この際、負極の長手方向の一端部の両面に負極集電体露出部が形成されるように、負極合剤スラリーの塗布位置を調整した。次に、巻回後に外周側端部の内側面に位置する予定の負極集電体露出部に、ニッケル製の負極タブを超音波溶接により取り付けた。次に、負極タブを覆うように負極集電体露出に絶縁テープを貼り合わせた。 (Negative electrode manufacturing process)
The negative electrode was prepared as follows. First, a paste-like negative electrode mixture slurry was obtained in the same manner as in Example 1. Next, a negative electrode mixture slurry was applied to both sides of a negative electrode current collector made of a strip-shaped copper foil (15 μm thick), dried, and then compression-molded with a roll press to form a negative electrode active material layer. .. At this time, the coating position of the negative electrode mixture slurry was adjusted so that the negative electrode current collector exposed portions were formed on both sides of one end portion in the longitudinal direction of the negative electrode. Next, a nickel negative electrode tab was attached by ultrasonic welding to the exposed negative electrode current collector, which is to be located on the inner surface of the outer peripheral end after winding. Next, an insulating tape was attached to the exposed negative electrode current collector so as to cover the negative electrode tab.
（電池の組み立て工程）
　電池を次のようにして組み立てた。まず、上述のようにして得られた正極と負極とを厚さ１０μｍの微多孔性ポリエチレン二軸延伸フィルムよりなるセパレータを介して、負極、セパレータ、正極、セパレータの順に積層した。次に、補強金属層および正極タブが取り付けられた正極の一端側から巻き始め、多数回巻回することにより、発電素子として巻回型電極体を得た。これ以降の工程は実施例１と同様にして円筒型の電池を得た。 (Battery assembly process)
The batteries were assembled as follows. First, the positive electrode and the negative electrode obtained as described above were laminated in the order of the negative electrode, the separator, the positive electrode, and the separator via a separator made of a microporous polyethylene biaxially stretched film having a thickness of 10 μm. Next, winding was started from one end side of the positive electrode to which the reinforcing metal layer and the positive electrode tab were attached, and the winding was performed many times to obtain a wound electrode body as a power generation element. In the subsequent steps, a cylindrical battery was obtained in the same manner as in Example 1.
［実施例２０］
　負極の作製工程において、負極合剤の材料およびその配合比を実施例２と同様にしたこと以外は実施例１９と同様にして電池を得た。 [Example 20]
A battery was obtained in the same manner as in Example 19 except that the material of the negative electrode mixture and the compounding ratio thereof were the same as in Example 2 in the process of producing the negative electrode.
［実施例２１］
　負極の作製工程において、補強金属層として、表１に示すように、厚さ５０μｍのＴｉ箔を用いたこと以外は実施例２０と同様にして電池を得た。 [Example 21]
As shown in Table 1, a battery was obtained in the same manner as in Example 20 except that a Ti foil having a thickness of 50 μm was used as the reinforcing metal layer in the process of manufacturing the negative electrode.
［比較例１］
　負極の作製工程において、負極集電体露出部に補強金属層を設けず、負極集電体露出部に直接ニッケル製の負極タブを超音波溶接により取り付けたこと以外は実施例１と同様にして電池を得た。 [Comparative Example 1]
In the process of manufacturing the negative electrode, the same as in Example 1 except that a reinforcing metal layer is not provided on the exposed portion of the negative electrode current collector and a nickel negative electrode tab is directly attached to the exposed portion of the negative electrode current collector by ultrasonic welding. I got a battery.
［比較例２］
　負極の作製工程において、負極合剤の材料の配合比を実施例１７と同様にしたこと以外は比較例１と同様にして電池を得た。 [Comparative Example 2]
A battery was obtained in the same manner as in Comparative Example 1 except that the compounding ratio of the material of the negative electrode mixture was the same as in Example 17 in the process of producing the negative electrode.
［比較例３］
　正極の作製工程において、正極集電体露出部に補強金属層を設けず、正極集電体露出部に直接アルミニウム製の正極タブを超音波溶接により取り付けたこと以外は実施例１７と同様にして電池を得た。 [Comparative Example 3]
In the process of manufacturing the positive electrode, the same as in Example 17 except that the reinforcing metal layer was not provided on the exposed portion of the positive electrode current collector and the positive electrode tab made of aluminum was directly attached to the exposed portion of the positive electrode current collector by ultrasonic welding. I got a battery.
［比較例４］
　正極の作製工程において、正極集電体露出部に樹脂フィルムを貼り合わせたこと以外は比較例３と同様にして電池を得た。なお、樹脂フィルムとしては、表１に示すように、１．６周巻回可能な長さで、正極集電体と同一の幅を有する、厚さ５００μｍの矩形状のポリプロピレン（ＰＰ）製樹脂フィルムを用いた。 [Comparative Example 4]
A battery was obtained in the same manner as in Comparative Example 3 except that a resin film was attached to the exposed portion of the positive electrode current collector in the process of producing the positive electrode. As the resin film, as shown in Table 1, a rectangular polypropylene (PP) resin having a thickness of 500 μm, which has a length that can be wound 1.6 times and has the same width as the positive electrode current collector. A film was used.
［比較例５］
　巻回型電極体の巻き始めにおいて正極を１．６周巻回することにより、電極体の中心孔補強部を形成したこと以外は比較例３と同様にして電池を得た。 [Comparative Example 5]
A battery was obtained in the same manner as in Comparative Example 3 except that the central hole reinforcing portion of the electrode body was formed by winding the positive electrode 1.6 times at the beginning of winding of the winding type electrode body.
［比較例５］
　巻回型電極体の巻き始めにおいて負極を１．６周巻回することにより、電極体の中心孔補強部を形成したこと以外は比較例２と同様にして電池を得た。 [Comparative Example 5]
A battery was obtained in the same manner as in Comparative Example 2 except that the central hole reinforcing portion of the electrode body was formed by winding the negative electrode 1.6 times at the beginning of winding of the winding type electrode body.
［評価］
＜低温サイクル試験前の落下試験によるショート発生率＞
　まず、落下試験により外部から電池に衝撃が加える過酷試験を行い、ショートが発生した電池の個数を求めた。次に、以下の式からショート発生率を求めた。
　（ショート発生率）［％］＝（（ショートが発生した電池の個数）／（落下試験を行った電池の個数））×１００ [Evaluation]
<Short occurrence rate by drop test before low temperature cycle test>
First, a harsh test was conducted in which a shock was applied to the batteries from the outside by a drop test, and the number of batteries in which a short circuit occurred was determined. Next, the short circuit occurrence rate was calculated from the following formula.
(Short occurrence rate) [%] = ((Number of batteries with short circuit) / (Number of batteries subjected to drop test)) x 100
　落下試験としては、「リチウム二次電池安全性評価基準ガイドライン」（SBA G1101）に規定されたものに一部改変を加えたものを採用した。具体的には、SBA G(23) JP 2018-10764 A 2018.1.181101に規定された落下試験は、１．９ｍからコンクリートに１０回落下させる試験であるが、本評価の落下試験ではこの落下回数ｎを２０回にして限界試験を行い、ｎ＝２０でのショート発生率を調査した。 For the drop test, the one specified in the "Lithium Secondary Battery Safety Evaluation Criteria Guideline" (SBA G1101) with some modifications was adopted. Specifically, the drop test specified in SBA G (23) JP 2018-10764 A 2018.1.181101 is a test in which the concrete is dropped 10 times from 1.9 m, but in the drop test of this evaluation, the number of drops is this. A limit test was conducted with n set to 20 times, and the short-circuit occurrence rate at n = 20 was investigated.
＜低温サイクル試験後の落下試験によるショート発生率＞
　まず、負極でのＬｉ析出により電極体が膨張し、内圧が上昇する低温（０℃）にてサイクル試験を行い、正極の巻き芯切断端部の段差でセパレータにダメージを与えた。その後、低温サイクル試験前の落下試験と同様にしてショート発生率を求めた。 <Short occurrence rate by drop test after low temperature cycle test>
First, a cycle test was conducted at a low temperature (0 ° C.) at which the electrode body expanded due to Li precipitation at the negative electrode and the internal pressure increased, and the separator was damaged at the step at the cut end of the winding core of the positive electrode. After that, the short circuit occurrence rate was determined in the same manner as in the drop test before the low temperature cycle test.
　以下に、低温サイクル試験の詳細を示す。
　　環境温度：０℃
　　充電：ＣＣ／ＣＶ、４．２５Ｖ／１Ｃ、１００ｍＡｃｕｔ
　　放電：２Ｃ、２Ｖｃｕｔ（放電後セル温度が０℃になったら充電再開）
　放電レートは、初期の放電容量に対する維持率［％］が３０％に到達する毎に、２Ｃ→１Ｃ→０．５Ｃと段階的に下げて行くことで加速サイクル的に劣化を促進させた。すなわち、初期の放電容量に対する維持率［％］が３０％以下到達時に２Ｃ→１Ｃに下げることで維持率が３０％以上に一時的に復帰してくるが、再度３０％以下になったら１Ｃ→０．５Ｃに下げるようにした。 The details of the low temperature cycle test are shown below.
Environmental temperature: 0 ° C
Charging: CC / CV, 4.25V / 1C, 100mAcut
Discharge: 2C, 2Vcut (Charging resumes when the cell temperature reaches 0 ° C after discharge)
The discharge rate was gradually lowered in the order of 2C → 1C → 0.5C every time the maintenance rate [%] with respect to the initial discharge capacity reached 30%, thereby accelerating the deterioration in an acceleration cycle. That is, when the maintenance rate [%] with respect to the initial discharge capacity reaches 30% or less, the maintenance rate temporarily returns to 30% or more by lowering it from 2C to 1C, but when it becomes 30% or less again, 1C → I tried to lower it to 0.5C.
＜座屈の発生率＞
　まず、ＣＴ（Computed Tomography）を用いて、“低温サイクル試験後の落下試験によるショート発生率”の評価後の電池の横断面画像（電池の高さ方向に垂直な断面画像）を、撮影した。次に、この断面画像から、電極体の巻回中心側の位置において負極または正極に座屈（図５参照）が発生しているか否かを確認し、以下の式から座屈の発生率を求めた。
　（座屈の発生率）［％］＝（（座屈の発生が確認された電池の個数）／（座屈の発生を確認した電池の個数））×１００ <Buckling rate>
First, using CT (Computed Tomography), a cross-sectional image (cross-sectional image perpendicular to the height direction of the battery) of the battery after evaluation of "short occurrence rate by drop test after low temperature cycle test" was taken. Next, from this cross-sectional image, it is confirmed whether or not buckling (see FIG. 5) occurs in the negative electrode or the positive electrode at the position on the winding center side of the electrode body, and the occurrence rate of buckling is calculated from the following formula. I asked.
(Buckling rate) [%] = ((Number of batteries confirmed to have buckling) / (Number of batteries confirmed to have buckling)) x 100
　実施例１～２１、比較例１～６の電池の構成および評価結果を示す。
Figure JPOXMLDOC01-appb-T000001
 The battery configurations and evaluation results of Examples 1 to 21 and Comparative Examples 1 to 6 are shown.
Figure JPOXMLDOC01-appb-T000001
　上記評価結果から以下のことがわかる。
　円筒状の補強金属層により中心孔が補強されている電池（実施例１～２１）では、円筒状の補強金属層により中心孔が補強されてない電池（比較例１～３）に比べて、ショートおよび座屈の発生率を低減することができる。
　円筒状の補強金属層により中心孔が補強されている電池（実施例１～２１）では、円筒状の樹脂フィルムにより中心孔が補強されている電池（比較例４）に比べて、ショートおよび座屈の発生率を低減することができる。
　円筒状の補強金属層により中心孔が補強されている電池（実施例１～２１）では、正極または負極を１．６周巻回することにより中心孔が補強されている電池（比較例５、６）に比べて、ショートおよび座屈の発生率を低減することができる。 The following can be seen from the above evaluation results.
The batteries in which the central hole is reinforced by the cylindrical reinforcing metal layer (Examples 1 to 21) are compared with the batteries in which the central hole is not reinforced by the cylindrical reinforcing metal layer (Comparative Examples 1 to 3). The incidence of shorts and buckling can be reduced.
Batteries in which the central hole is reinforced by a cylindrical reinforcing metal layer (Examples 1 to 21) are short-circuited and buckled as compared with batteries in which the central hole is reinforced by a cylindrical resin film (Comparative Example 4). The incidence of bending can be reduced.
In the batteries in which the central hole is reinforced by a cylindrical reinforcing metal layer (Examples 1 to 21), the battery in which the central hole is reinforced by winding the positive electrode or the negative electrode 1.6 times (Comparative Example 5, Compared with 6), the occurrence rate of short circuit and buckling can be reduced.
　補強金属層の材料として、Ｃｕ、ＣｕＮｉ合金、Ｎｉ、ＣｕＺｎ合金およびＣｕＺｎＮｉ合金のいずれを用いた場合にも、ショートおよび座屈の発生率を低減することができる（実施例２～６）。 When any of Cu, CuNi alloy, Ni, CuZn alloy and CuZnNi alloy is used as the material of the reinforcing metal layer, the occurrence rate of short circuit and buckling can be reduced (Examples 2 to 6).
　座屈の発生率を低減する観点からすると、補強金属層の厚さは２０μｍ以上であることが好ましい（実施例７～１０）。 From the viewpoint of reducing the occurrence rate of buckling, the thickness of the reinforcing metal layer is preferably 20 μm or more (Examples 7 to 10).
　座屈の発生率を低減する観点からすると、補強金属層の巻回数は１．２以上であることが好ましい（実施例１１～１４）。 From the viewpoint of reducing the occurrence rate of buckling, the number of turns of the reinforcing metal layer is preferably 1.2 or more (Examples 11 to 14).
　負極活物質としてケイ素含有材料（ＳｉＯ）を含む場合にも、円筒状の補強金属層により中心孔が補強されていることで、ショートおよび座屈の発生率を低減することができる（実施例１、８、１７、１８）。 Even when a silicon-containing material (SiO) is contained as the negative electrode active material, the occurrence rate of short circuit and buckling can be reduced by reinforcing the central hole by the cylindrical reinforcing metal layer (Example 1). , 8, 17, 18).
　１１　　電池缶
　１２、１３　　絶縁板
　１４　　電池蓋
　１５　　安全弁機構
　１５Ａ　　ディスク板
　１６　　熱感抵抗素子
　１７　　ガスケット
　２０　　巻回型電極体
　２１　　正極
　２１Ａ　　正極集電体
　２１Ｂ　　正極活物質層
　２１Ｃ１、２１Ｃ２　　正極集電体露出部
　２１Ｄ　　先端
　２１Ｓ１　　内側面
　２１Ｓ２　　外側面
　２２　　負極
　２２Ａ　　負極集電体
　２２Ｂ　　負極活物質層
　２２Ｃ１、２２Ｃ１、２２Ｄ１、２２Ｄ２　　負極集電体露出部
　２２Ｓ１　　内側面
　２２Ｓ２　　外側面
　２３　　セパレータ
　２４　　補強金属層
　２５　　正極リード
　２６、２７　　負極リード 11 Battery can 12, 13 Insulation plate 14 Battery lid 15 Safety valve mechanism 15A Disc plate 16 Heat-sensitive resistance element 17 Gasket 20 Winding type electrode body 21 Positive electrode 21A Positive electrode current collector 21B Positive electrode active material layer 21C1, 21C2 Positive electrode current collector exposed Part 21D Tip 21S1 Inner side 21S2 Outer side 22 Negative electrode 22A Negative electrode current collector 22B Negative electrode active material layer 22C1, 22C1, 22D1, 22D2 Negative electrode current collector exposed part 22S1 Inner side surface 22S2 Outer side surface 23 Separator 24 Reinforcing metal layer , 27 Negative lead

Claims (10)

  1. 　正極と、負極とを備える巻回型の電極体を備え、
    　前記負極は、
    　第１の面および第２の面を有する負極集電体と、
    　前記電極体の巻回中心側端部において前記第１の面が露出するように、前記第１の面および前記第２の面上に設けられた負極活物質層と、
    　前記巻回中心側端部において露出した前記第１の面上に設けられた金属層と
    　を備え、
    　前記金属層は、筒状に巻回されている電池。     A wound electrode body including a positive electrode and a negative electrode is provided.
    The negative electrode is
    A negative electrode current collector having a first surface and a second surface,
    A negative electrode active material layer provided on the first surface and the second surface so that the first surface is exposed at the winding center side end portion of the electrode body.
    A metal layer provided on the first surface exposed at the winding center side end is provided.
    The metal layer is a battery wound in a tubular shape.
  2. 　前記正極は、第３の面および第４の面を有する正極集電体と、前記第３の面および前記第４の面上に設けられた正極活物質層とを備え、
    　前記正極の巻回中心側端部の前記第３の面および前記第４の面は、前記正極活物質層により覆われている請求項１に記載の電池。     The positive electrode includes a positive electrode current collector having a third surface and a fourth surface, and a positive electrode active material layer provided on the third surface and the fourth surface.
    The battery according to claim 1, wherein the third surface and the fourth surface of the winding center side end portion of the positive electrode are covered with the positive electrode active material layer.
  3. 　前記金属層上に設けられた負極タブをさらに備える請求項１または２に記載の電池。 The battery according to claim 1 or 2, further comprising a negative electrode tab provided on the metal layer.
  4. 　前記第１の面は、前記負極集電体の内側面である請求項１から３のいずれかに記載の電池。 The battery according to any one of claims 1 to 3, wherein the first surface is an inner surface of the negative electrode current collector.
  5. 　前記金属層が、銅、銅ニッケル合金、ニッケル、亜鉛、銅亜鉛合金または銅亜鉛ニッケル合金を含む請求項１から４のいずれかに記載の電池。 The battery according to any one of claims 1 to 4, wherein the metal layer contains copper, copper-nickel alloy, nickel, zinc, copper-zinc alloy or copper-zinc-nickel alloy.
  6. 　前記金属層の厚みが、２０μｍ以上１００μｍ以下である請求項１から５のいずれかに記載の電池。 The battery according to any one of claims 1 to 5, wherein the thickness of the metal layer is 20 μm or more and 100 μm or less.
  7. 　前記金属層の巻回数は、１．２周以上３周以下である請求項１から６のいずれかに記載の電池。 The battery according to any one of claims 1 to 6, wherein the number of turns of the metal layer is 1.2 or more and 3 or less.
  8. 　前記負極活物質層は、炭素含有材料を含む第１の負極活物質と、ケイ素含有材料を含む第２の負極活物質とを含む請求項１から７のいずれかに記載の電池。 The battery according to any one of claims 1 to 7, wherein the negative electrode active material layer includes a first negative electrode active material containing a carbon-containing material and a second negative electrode active material containing a silicon-containing material.
  9. 　前記負極活物質層中における前記第２の負極活物質の含有量は、５質量％以上２０質量％以下である請求項８に記載の電池。 The battery according to claim 8, wherein the content of the second negative electrode active material in the negative electrode active material layer is 5% by mass or more and 20% by mass or less.
  10. 　正極と、負極とを備える巻回型の電極体を備え、
    　前記正極および前記負極のうち、前記電極体の最内周に位置する電極は、
    　第１の面および第２の面を有する集電体と、
    　前記電極体の巻回中心側の端部において前記第１の面が露出するように、前記第１の面および前記第２の面上に設けられた活物質層と、
    　前記巻回中心側の端部において露出した前記第１の面上に設けられた金属層と
    　を備え、
    　前記金属層は、筒状に巻回されている電池。     A wound electrode body including a positive electrode and a negative electrode is provided.
    Of the positive electrode and the negative electrode, the electrode located on the innermost circumference of the electrode body is
    A current collector having a first surface and a second surface,
    An active material layer provided on the first surface and the second surface so that the first surface is exposed at the end of the electrode body on the winding center side.
    The metal layer provided on the first surface exposed at the end on the winding center side is provided.
    The metal layer is a battery wound in a tubular shape.
PCT/JP2020/022353 2019-08-15 2020-06-05 Battery WO2021029126A1 (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002100364A (en) * 2000-09-20 2002-04-05 Hitachi Cable Ltd ELECTRODE MATERIAL FOR Li ION CELL, AND Li ION CELL
JP2008218202A (en) * 2007-03-05 2008-09-18 Sony Corp Electrode and battery
JP2013025912A (en) * 2011-07-19 2013-02-04 Hitachi Ltd Wound secondary battery and manufacturing method therefor
WO2019009239A1 (en) * 2017-07-03 2019-01-10 株式会社村田製作所 Secondary battery, battery pack, electric vehicle, power storage system, power tool, and electronic device
JP2019067579A (en) * 2017-09-29 2019-04-25 日立化成株式会社 Lithium ion secondary battery and negative electrode material for lithium ion secondary battery

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002100364A (en) * 2000-09-20 2002-04-05 Hitachi Cable Ltd ELECTRODE MATERIAL FOR Li ION CELL, AND Li ION CELL
JP2008218202A (en) * 2007-03-05 2008-09-18 Sony Corp Electrode and battery
JP2013025912A (en) * 2011-07-19 2013-02-04 Hitachi Ltd Wound secondary battery and manufacturing method therefor
WO2019009239A1 (en) * 2017-07-03 2019-01-10 株式会社村田製作所 Secondary battery, battery pack, electric vehicle, power storage system, power tool, and electronic device
JP2019067579A (en) * 2017-09-29 2019-04-25 日立化成株式会社 Lithium ion secondary battery and negative electrode material for lithium ion secondary battery

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