WO2013080459A1 - Électrode négative pour batterie à lithium-ion et batterie à lithium-ion - Google Patents

Électrode négative pour batterie à lithium-ion et batterie à lithium-ion Download PDF

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Publication number
WO2013080459A1
WO2013080459A1 PCT/JP2012/007250 JP2012007250W WO2013080459A1 WO 2013080459 A1 WO2013080459 A1 WO 2013080459A1 JP 2012007250 W JP2012007250 W JP 2012007250W WO 2013080459 A1 WO2013080459 A1 WO 2013080459A1
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negative electrode
active material
current collector
lithium ion
electrode lead
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PCT/JP2012/007250
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English (en)
Japanese (ja)
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古結　康隆
心 原口
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パナソニック株式会社
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/531—Electrode connections inside a battery casing
    • H01M50/536—Electrode connections inside a battery casing characterised by the method of fixing the leads to the electrodes, e.g. by welding
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/386—Silicon or alloys based on silicon
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/387—Tin or alloys based on tin
    • 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
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/531—Electrode connections inside a battery casing
    • H01M50/534—Electrode connections inside a battery casing characterised by the material of the leads or tabs
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/134—Electrodes based on metals, Si or alloys
    • 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 negative electrode for a lithium ion battery and a lithium ion battery, and more particularly to an improvement in a joining technique between a negative electrode current collector and a negative electrode lead in a negative electrode for a lithium ion battery containing an alloy-based active material.
  • Lithium ion batteries are widely used as power sources for electronic devices and the like because they have high capacity and high energy density, and are easy to reduce in size and weight.
  • Electronic devices include mobile phones, personal digital assistants (PDAs), notebook personal computers, video cameras, and portable game machines.
  • a typical lithium ion battery includes a positive electrode containing a lithium cobalt composite oxide, a negative electrode containing graphite, and a polyolefin separator.
  • Each of the positive electrode and the negative electrode includes a current collector, an active material layer, and a lead.
  • the active material layer is formed on the surface of the current collector.
  • the lead is welded to an exposed portion of the surface of the current collector where the active material layer is not formed. Resistance welding and ultrasonic welding are used for lead welding.
  • the exposed portion is formed by providing an active material layer with a space on the surface of the current collector, or by removing a part of the active material layer after forming the active material layer on the surface of the current collector.
  • Typical alloy-based active materials include silicon-based active materials such as silicon and silicon oxide.
  • a negative electrode containing an alloy-based active material is generally composed of a negative electrode current collector and a thin film of an alloy-based active material formed on the surface of the negative electrode current collector by a vapor phase method (hereinafter referred to as “thin film-shaped negative electrode active material” Layer).
  • a vapor phase method hereinafter referred to as “thin film-shaped negative electrode active material” Layer.
  • Patent Document 1 discloses a technique for joining a negative electrode current collector and a negative electrode lead by irradiating a laser beam onto a laminate of a negative electrode plate and a negative electrode lead.
  • the negative electrode plate is composed of a negative electrode current collector and a thin film negative electrode active material layer formed on both surfaces thereof.
  • Patent Document 1 by irradiating the laminated body with a laser, a through hole penetrating the laminated body in the thickness direction is formed, and a part of the negative electrode lead is melted to form a negative electrode on the inner peripheral surface of the through hole. It is in contact with the current collector.
  • Patent Document 1 particles of an alloy-based active material are mixed in the joint between the negative electrode current collector and the negative electrode lead.
  • the alloy-based active material particles flow out of the thin-film negative electrode active material layer when the through-hole is formed by laser irradiation. Since the alloy-based active material has a high melting point, it is difficult to melt even when irradiated with a laser. Therefore, the mixing of the alloy-based active material into the joint portion reduces the joint strength of the joint portion. In addition, since the alloy-based active material has a large electric resistance, the mixing of the alloy-based active material into the joint decreases the conductivity of the joint.
  • Patent Document 2 discloses a technique in which a negative electrode lead made of copper, a copper alloy, or a copper clad material is joined to the surface of a thin-film negative electrode active material layer containing an alloy-based active material by resistance welding. However, almost no current flows through the thin film negative electrode active material layer. For this reason, in the technique of Patent Document 2, although the negative electrode current collector or the negative electrode lead may be locally melted, the thin film negative electrode active material layer is hardly melted. Therefore, the bonding strength between the negative electrode current collector and the negative electrode lead is low.
  • a silicon-based active material was deposited on the surface of a current collector made of copper foil or the like by vacuum deposition or the like.
  • Silicon-based negative electrodes are known.
  • the process for connecting the negative electrode lead to the current collector is complicated. Specifically, in order to form the exposed portion for connecting the negative electrode lead on the surface of the current collector, for example, by masking the exposed area of the surface of the current collector during vacuum deposition or the like, It was necessary to prevent the silicon-based active material from being deposited on the region. Such a mask operation becomes very complicated in terms of the process.
  • the inventors have made a negative electrode plate in which active material layers made of a silicon-based active material or the like are provided on both sides of a current collector, and a group consisting of nickel, nickel alloy, copper, and copper alloy.
  • a method of joining a negative electrode lead containing at least one selected by arc welding has been proposed (see Patent Document 3). Specifically, a part of the negative electrode lead is brought into contact with the active material layer, and arc welding is performed on a contact portion between the active material layer and the negative electrode lead.
  • a silicon-based alloy layer is formed between the current collector and the negative electrode lead, and as a result, an electrically good connection state is obtained between the current collector and the negative electrode lead.
  • Such a silicon-based alloy layer is formed by melting and resolidifying the active material layer together with the current collector and the negative electrode lead.
  • FIG. 7 (a) and 7 (b) are a top view and a side view, respectively, schematically showing the connection state of the silicon-based negative electrode plate by arc welding.
  • the negative electrode current collector 110 and the negative electrode lead 113 of the silicon negative electrode plate 100 are formed by arc welding to the contact portion between the silicon active material layer 111 and the negative electrode lead 113 of the silicon negative electrode plate 100. They are connected to each other via the layer 117 (melting part). According to such a joining method by arc welding, a step of exposing a part of the surface of the negative electrode current collector becomes unnecessary. Therefore, such a joining method can be easily performed and is therefore industrially advantageous.
  • the inventors have found the following new problem in the joining method by arc welding described above. That is, when arc welding is performed on the contact portion between the silicon-based negative electrode plate 100 and the negative electrode lead 113, the arc irradiation width is made larger than the width of the negative electrode lead 113 so that the arc is not irradiated to a portion different from the contact portion. It was small. For this reason, it was found that sufficient bonding strength could not be obtained between the negative electrode current collector 110 and the negative electrode lead 113.
  • the stress applied to the negative electrode lead 113 in the manufacturing process and the stress applied to the negative electrode lead 113 after manufacturing the battery are likely to concentrate, and the molten part breaks. Is likely to occur.
  • the burr generated when the end portion of the negative electrode lead is cut damages the separator when the positive electrode, the negative electrode, and the separator are stacked to form an electrode group, thereby electrically connecting the positive electrode and the negative electrode. It is easy to cause problems such as short circuit.
  • an object of the present invention is to provide a negative electrode for a lithium ion battery in which the junction between the negative electrode current collector and the negative electrode lead is not easily broken, and to provide a lithium ion battery having high capacity and high output.
  • the negative electrode for a lithium ion battery according to the present invention includes a negative electrode plate, a negative electrode lead, and a melting part.
  • the negative electrode plate has a current collector and a thin film negative electrode active material layer formed on the surface of the current collector, and the thin film negative electrode active material layer contains an alloy-based active material.
  • the negative electrode lead is electrically connected to the negative electrode plate.
  • the melting portion is formed across the end face of the negative electrode plate and the end face of the negative electrode lead, and the negative electrode lead is welded to the current collector.
  • the negative electrode plate On the end surface of the negative electrode plate, there are a first region that forms an end surface of a portion of the negative electrode plate that faces the negative electrode lead, and a second region that forms an end surface of a portion of the negative electrode plate that does not face the negative electrode lead. Yes. A part of the melted part is formed in the first region, and a remaining part of the melted part is also formed in a part of the second region, whereby the width of the melted part becomes larger than the width of the negative electrode lead. Yes.
  • the lithium ion battery according to the present invention includes a positive electrode, the negative electrode, a separator, and a lithium ion conductive nonaqueous electrolyte.
  • the positive electrode has a positive electrode current collector, a positive electrode active material layer formed on the surface of the positive electrode current collector, and a positive electrode lead electrically connected to the positive electrode current collector.
  • the separator is interposed between the positive electrode and the negative electrode.
  • the junction between the negative electrode current collector and the negative electrode lead is hardly broken.
  • the lithium ion battery according to the present invention has a high capacity and a high output, and is excellent in battery performance such as cycle characteristics.
  • the negative electrode for a lithium ion battery according to the present invention includes a negative electrode plate, a negative electrode lead, and a melting part.
  • the negative electrode plate has a current collector and a thin film negative electrode active material layer formed on the surface of the current collector, and the thin film negative electrode active material layer contains an alloy-based active material.
  • the negative electrode lead is electrically connected to the negative electrode plate.
  • the melting portion is formed across the end face of the negative electrode plate and the end face of the negative electrode lead, and the negative electrode lead is welded to the current collector.
  • the negative electrode plate On the end surface of the negative electrode plate, there are a first region that forms an end surface of a portion of the negative electrode plate that faces the negative electrode lead, and a second region that forms an end surface of a portion of the negative electrode plate that does not face the negative electrode lead. Yes. A part of the melted part is formed in the first region, and a remaining part of the melted part is also formed in a part of the second region, whereby the width of the melted part becomes larger than the width of the negative electrode lead. Yes.
  • the negative electrode current collector and the negative electrode lead are firmly joined by the melted portion. Therefore, the junction between the negative electrode current collector and the negative electrode lead is not easily broken. Moreover, an electrically favorable connection state is obtained between the negative electrode current collector and the negative electrode lead by the melting portion. Therefore, high electrical conductivity is realized between the negative electrode current collector and the negative electrode lead.
  • melting part is 0.5 N / mm or more and 50 N / mm or less.
  • the width of the portion provided in the second region of the melted portion is preferably 0.1 mm or more and 10 mm or less. Moreover, it is preferable that the fusion
  • the width is 0.1 mm or more, the necessary bonding strength can be obtained between the negative electrode current collector and the negative electrode lead.
  • the width is 10 mm or less, when the electrode group is formed by making the negative electrode and the positive electrode face each other, it is difficult to cause a loss in the facing area between the negative electrode and the positive electrode, and a high-capacity battery can be designed.
  • the portion provided in the second region of the melted portion preferably contains an alloy composed of an element of an alloy-based active material and an element of a current collector.
  • the element of the alloy-based active material is preferably silicon or tin
  • the metal element of the current collector is preferably copper or nickel.
  • the lithium ion battery according to the present invention includes a positive electrode, the negative electrode, a separator, and a lithium ion conductive nonaqueous electrolyte.
  • the positive electrode has a positive electrode current collector, a positive electrode active material layer formed on the surface of the positive electrode current collector, and a positive electrode lead electrically connected to the positive electrode current collector.
  • the separator is interposed between the positive electrode and the negative electrode.
  • the lithium ion battery when it includes the negative electrode, high capacity and high output are realized. Therefore, the lithium ion battery is excellent in battery performance such as output characteristics and cycle characteristics.
  • the negative electrode as described above, the negative electrode current collector and the negative electrode lead are firmly bonded, and an electrically good connection state is realized between them. Therefore, the current collection performance of the negative electrode and the output characteristics of the battery are maintained at a high level over a long period of time. Therefore, the lithium ion battery has a long service life.
  • FIG. 1A and FIG. 1B are a top view and a side view, respectively, showing a simplified configuration of the main part of the negative electrode for a lithium ion battery according to this embodiment.
  • the negative electrode includes a negative electrode plate 1, a negative electrode lead 13, and a melting part 17.
  • the negative electrode plate 1 has a negative electrode current collector 10 and a thin film negative electrode active material layer 11 formed on the surface of the negative electrode current collector 10.
  • the thin film negative electrode active material layer 11 is formed on both surfaces in the thickness direction of the negative electrode current collector 10.
  • Nonporous conductive substrates include foils, sheets, films, and the like.
  • Examples of the material of the conductive substrate include stainless steel, titanium, nickel, copper, and copper alloy.
  • the thickness of the conductive substrate is usually 1 to 500 ⁇ m, preferably 1 to 50 ⁇ m, more preferably 10 to 40 ⁇ m, and still more preferably 10 to 30 ⁇ m.
  • the thin film negative electrode active material layer 11 contains an alloy-based active material.
  • the alloy-based active material is an active material containing an element (such as Si or Sn) that can reversibly form an alloy with lithium.
  • the thin-film negative electrode active material layer 11 may contain a known negative electrode active material other than the alloy-based active material, an additive, and the like as long as the characteristics thereof are not impaired along with the alloy-based active material.
  • a preferred form of the thin-film negative electrode active material layer 11 is an amorphous or low crystalline thin film containing an alloy-based active material and having a thickness of 3 to 50 ⁇ m.
  • the alloy-based active material absorbs lithium at the time of charging and forms an alloy at the negative electrode potential, and releases lithium at the time of discharging.
  • the alloy-based active material known materials can be used without particular limitation. Among them, a silicon-based active material and a tin-based active material are preferable, and a silicon-based active material is particularly preferable.
  • silicon-based active materials include silicon, silicon compounds, partial substitutes thereof, and solid solutions.
  • Silicon compounds include silicon oxide, silicon carbide, silicon nitride, silicon alloy and the like, and among these, silicon oxide is particularly preferable.
  • Silicon oxide includes silicon oxide represented by SiO a (0.05 ⁇ a ⁇ 1.95).
  • Silicon carbide includes silicon carbide represented by SiC b (0 ⁇ b ⁇ 1).
  • Silicon nitride includes silicon nitride represented by SiN c (0 ⁇ c ⁇ 4/3).
  • the silicon alloy is an alloy of silicon and a different element A.
  • the different element A at least one element selected from the group consisting of Fe, Co, Sb, Bi, Pb, Ni, Cu, Zn, Ge, In, Sn, and Ti can be used.
  • the partially substituted body is a compound in which a part of silicon contained in silicon or a silicon compound is substituted with a different element B.
  • the heterogeneous element B is at least selected from the group consisting of B, Mg, Ni, Ti, Mo, Co, Ca, Cr, Cu, Fe, Mn, Nb, Ta, V, W, Zn, C, N, and Sn.
  • One element can be used.
  • Examples of the tin-based active material include tin, tin oxide, tin nitride, tin alloy, tin compound, and a solid solution thereof.
  • tin oxide is particularly preferable.
  • Examples of the tin oxide include tin oxides such as SnO d (0 ⁇ d ⁇ 2) and SnO 2 .
  • Examples of tin alloys include Ni—Sn alloys, Mg—Sn alloys, Fe—Sn alloys, Cu—Sn alloys, Ti—Sn alloys, and the like.
  • Examples of the tin compound include SnSiO 3 , Ni 2 Sn 4 , and Mg 2 Sn.
  • the thin film negative electrode active material layer 11 may contain one kind of alloy-based active material alone, or may contain two or more kinds of alloy-based active materials in combination.
  • the thin film negative electrode active material layer 11 is a deposited film formed in a thin film shape on the surface of the negative electrode current collector 10 by a vapor phase method.
  • the vapor phase method include a vacuum deposition method, a sputtering method, an ion plating method, a laser ablation method, a chemical vapor deposition (CVD) method, a plasma chemical vapor deposition method, and a thermal spray method.
  • the vacuum evaporation method is particularly preferable.
  • the negative electrode current collector 10 is disposed above the silicon target in the vertical direction. Silicon vapor is generated by irradiating the silicon target with an electron beam, and this silicon vapor is deposited on the surface of the negative electrode current collector 10. Thereby, a thin film negative electrode active material layer 11 made of silicon is formed on the surface of the negative electrode current collector 10. At this time, when oxygen or nitrogen is supplied into the electron beam vacuum deposition apparatus, a thin film negative electrode active material layer 11 containing silicon oxide or silicon nitride is formed.
  • the thin-film negative electrode active material layer 11 is formed as a thin-film solid film, but is not limited thereto, and may be formed in a pattern shape such as a lattice by a vapor phase method. It may be formed as an assembly of columnar bodies.
  • the plurality of columnar bodies each contain an alloy-based active material, and are formed so as to extend outward from the surface of the negative electrode current collector 10 and to be separated from each other.
  • the thin film negative electrode active material layer 11 is composed of a plurality of columnar bodies, a plurality of convex portions are regularly or irregularly formed on the surface of the negative electrode current collector 10, and one columnar body is formed on the surface of one convex portion. Is preferably formed.
  • the shape of the convex portion when viewed from the direction perpendicular to the surface of the negative electrode current collector 10 is a rhombus, a circle, an ellipse, a polygon (triangle, octagon, etc.), and the like.
  • the arrangement of the convex portions on the surface of the negative electrode current collector 10 includes a grid-like arrangement, a lattice arrangement, a staggered arrangement, a close-packed arrangement, and the like. Further, the convex portion is formed on one surface or both surfaces in the thickness direction of the negative electrode current collector 10. Further, the height of the columnar body is preferably 3 ⁇ m to 30 ⁇ m.
  • the negative electrode lead 13 contains at least one metal or alloy selected from the group consisting of nickel, nickel alloy, copper, and copper alloy.
  • nickel alloy include a nickel-silicon alloy, a nickel-tin alloy, a nickel-cobalt alloy, a nickel-iron alloy, and a nickel-manganese alloy.
  • Copper alloys include copper-nickel alloy, copper-iron alloy, copper-silver alloy, copper-phosphorus alloy, copper-aluminum alloy, copper-silicon alloy, copper-tin alloy, copper-zirconia alloy, copper-beryllium alloy, etc. There is.
  • nickel, copper, and a copper-nickel alloy are preferable, and copper is particularly preferable.
  • a clad material of copper and nickel may be used.
  • the negative electrode lead 13 is manufactured by molding the above-described metal or alloy into a general lead form.
  • the thickness is 0.01 to 0.5 mm, and the width is 2 to 100 mm.
  • the melting part 17 is continuously formed across the end surface 1a of the negative electrode plate 1 and the end surface 13a of the negative electrode lead 13, thereby making the negative electrode current collector 10 and the negative electrode lead 13 conductive, and the negative electrode collector.
  • the electric body 10 and the negative electrode lead 13 are joined to each other.
  • the width of the melting part 17 is larger than the width of the negative electrode lead 13.
  • the end surface 1 a of the negative electrode plate 1 includes a first region 1 b that constitutes an end surface of a portion of the negative electrode plate 1 that faces the negative electrode lead 13, and a portion of the negative electrode plate 1 that does not face the negative electrode lead 13.
  • a part of the melting part 17 is formed in the first region 1b, and a remaining part of the melting part 17 is also formed in a part of the second region 1c.
  • the melting part 17 is continuously formed from the first region 1b to the second region 1c.
  • the width W of the portion provided in the second region 1c of the melted portion 17 is defined as the dimension from the side end of the negative electrode lead 13 to the end of the melted portion 17 (the dimension indicated by the double arrow in FIG. 1A). Then, it is preferable that the width W is 0.1 mm or more and 10 mm or less.
  • the melting portion 17 is continuously formed in the entire first region 1b and the end surface 13a of the end surface 1a.
  • the both ends about the width direction of the negative electrode lead 13 should just be joined to the negative electrode collector 10, Therefore Therefore, the fusion
  • the portion of the melted portion 17 provided in the first region 1b is formed by performing arc welding on the contact portion between the negative electrode plate 1 and the negative electrode lead 13 as described later. Specifically, in the portion subjected to arc welding, the negative electrode lead 13, the negative electrode current collector 10, and the thin film negative electrode active material layer 11 are melted and the elements contained therein are uniformly dispersed. Alloying occurs. In this manner, a portion provided in the first region 1b of the melted portion 17 is formed, and the negative electrode current collector 10 and the negative electrode lead 13 are firmly bonded by the portion.
  • the negative electrode current collector 10 and the thin film negative electrode active material layer 11 are melted in the portion irradiated with the arc, respectively. Alloying occurs when the contained elements are uniformly dispersed. The melted portion formed in this manner has higher strength than the negative electrode plate 1.
  • the part formed in the first region 1b and the part formed in the second region 1c are connected to each other. Therefore, even if stress is applied to the joint end portion of the negative electrode lead 13 due to the twist or deformation of the negative electrode lead 13, the joint between the negative electrode current collector 10 and the negative electrode lead 13 is not easily broken. In addition, the negative electrode plate 1 is hardly cracked or broken in the vicinity of the joint end portion of the negative electrode lead 13. That is, the connection reliability between the negative electrode current collector 10 and the negative electrode lead 13 is enhanced by forming the melted portion 17 having high strength in the entire region where stress is likely to concentrate.
  • the melting part 17 has high conductivity, and makes the negative electrode current collector 10 and the negative electrode lead 13 conductive. Therefore, the negative electrode according to the present embodiment has high bonding strength between the negative electrode current collector 10 and the negative electrode lead 13 and exhibits high current collecting performance.
  • the melting part 17 includes, for example, an alloy of a metalloid element contained in the negative electrode current collector 10 or the negative electrode lead 13 and a metalloid element contained in the alloy-based negative electrode active material in the thin film negative electrode active material layer 11. It is out.
  • the metalloid element contained in the alloy-based negative electrode active material include silicon and tin.
  • main metal elements contained in the negative electrode current collector 10 and the negative electrode lead 13 include copper and nickel. Among these, copper is particularly preferable in consideration of uniformly dispersing the metalloid element contained in the alloy-based negative electrode active material.
  • FIG. 5A and FIG. 5B are diagrams showing a method for producing a sample used for measuring the tensile strength of the negative electrode lead 13 with respect to the negative electrode current collector 10.
  • FIG. 6 is a perspective view schematically showing a method for measuring the tensile strength of the negative electrode lead 13 with respect to the negative electrode current collector 10.
  • the negative electrode lead 13 is cut so that the length of the negative electrode lead 13 is the same as the width of the negative electrode plate 1.
  • the length of the negative electrode plate 1 is adjusted by cutting the negative electrode plate 1 so that the negative electrode plate 1 can be easily fixed to the lower fixing jig 71 described later.
  • the negative electrode current collector 10 and the negative electrode lead 13 are bonded to each other with a bonding width d by the melting portion 17.
  • the bonding width d is equal to the width of the negative electrode lead 13.
  • the negative electrode lead 13 is turned up in the direction of the arrow 66 by raising the negative electrode lead 13 from the negative electrode plate 1. In this way, a sample 65 for tensile strength measurement is prepared.
  • the lower fixing jig 71 of the universal testing machine 70 is opposite to the end of the negative electrode plate 1 where the melted portion 17 is formed. Fix it with the side edge. Further, the upper fixing jig 72 is fixed by sandwiching the end portion of the negative electrode lead 13 opposite to the end portion where the melted portion 17 is formed.
  • the negative electrode lead 13 is pulled up with respect to the negative electrode plate 1 by moving the upper fixing jig 72 in the direction of the arrow 73 at a speed of 5 mm / min at a room temperature of 25 ° C.
  • the tensile strength (N) when the junction part (melting part 17) of the negative electrode plate 1 and the negative electrode lead 13 fractures is measured.
  • the tensile strength (N / mm) per 1 mm of the bonding width is determined from the measured value of the tensile strength and the measured value of the bonding width d.
  • the welding conditions are set so that the bonding strength between the negative electrode plate 1 and the negative electrode lead 13 is 0.5 N / mm or more and 50 N / mm or less. It is desirable.
  • This manufacturing method includes a first step, a second step, and a third step.
  • a first step a second step
  • a third step a third step.
  • 2A and 2B are a top view and a longitudinal sectional view, respectively, used for explaining the method for manufacturing a negative electrode for a lithium ion battery according to this embodiment.
  • the negative electrode plate 1 and the negative electrode lead 13 are prepared.
  • the negative electrode plate 1 includes a negative electrode current collector 10 and a thin film negative electrode active material layer 11 formed on both surfaces in the thickness direction of the negative electrode current collector 10 (see FIG. 2B).
  • the thin film negative electrode active material layer 11 may be formed only on one surface of the negative electrode current collector 10.
  • a welding jig 14 composed of a first plate 20 and a second plate 21 is prepared (see FIG. 2B).
  • the welding jig 14 is produced by forming a metal material such as copper into a predetermined shape.
  • the negative electrode plate 1 and the negative electrode lead 13 are sandwiched between the first plate 20 and the second plate 21.
  • the surface of the negative electrode lead 13 is placed on the surface of the thin film negative electrode active material layer 11 so that the end surface 1a of the negative electrode plate 1 and the end surface 13a of the negative electrode lead 13 are aligned on the same plane. Are superimposed.
  • a flat weld end face 16 composed of the end faces 1 a and 13 a is exposed from the welding jig 14.
  • the surface of the thin film negative electrode active material layer 11 is one surface in the thickness direction of the thin film negative electrode active material layer 11.
  • the surface of the negative electrode lead 13 is one surface in the thickness direction of the negative electrode lead 13.
  • the entire surface of the thin-film negative electrode active material layer 11 and the entire surface of the negative electrode lead 13 do not need to overlap each other, and at least a part of each surface may overlap and be in contact with each other.
  • the end face 1 a of the negative electrode plate 1 is one end face in the width direction of the negative electrode plate 1, and the end face 13 a of the negative electrode lead 13 is one end face in the longitudinal direction of the negative electrode lead 13.
  • the end surface 1a of the negative electrode plate 1 may be the other end surface in the width direction of the negative electrode plate 1, or the end surface in the longitudinal direction of the negative electrode plate 1.
  • the end surface 13 a of the negative electrode lead 13 may be the other end surface in the longitudinal direction of the negative electrode lead 13, or may be the end surface in the width direction of the negative electrode lead 13.
  • the end faces 1a and 13a are formed of electrode groups (winding type, flat type, laminated type, etc.), lithium ion battery types (square type, cylindrical type, flat type, laminated film pack type, coin type, etc.), And it selects suitably according to conditions, such as a design (a dimension, a capacity
  • the first plate 20 when the negative electrode plate 1 and the negative electrode lead 13 are sandwiched between the first plate 20 and the second plate 21 of the welding jig 14, the first plate 20.
  • a first recess 20x is formed between the end surface of the negative electrode lead 13 and the end surface 13a of the negative electrode lead 13, and a second recess 21x is formed between the end surface of the second plate 21 and the end surface 1a of the negative electrode plate 1.
  • the first plate 20 and the second plate 21 are each provided with a notch.
  • the third step arc discharge is performed toward the welding region in which the melted portion 17 is formed in the weld end face 16. Thereby, the welding region is melted, and the negative electrode lead 13 is welded to the negative electrode current collector 10.
  • an arc welding electrode (not shown) is applied so that the arc is irradiated perpendicularly to the welding end face 16 (in the direction of the arrow 19 shown in FIGS. 2A and 2B). Place. Then, while moving the welding torch of the electrode for arc welding along the welding end face 16 (in the direction of the arrow 18 shown in FIG. 2A), the arc is continuously emitted from the welding torch in the direction of the arrow 19. To do. At this time, the moving distance of the welding torch is set larger than the width of the negative electrode lead 13. The arc emitted from the welding torch is applied to the weld end face 16, thereby uniformly melting the weld region of the weld end face 16. Thereafter, the melted portion 17 is formed by solidifying the melted portion. A part of the melted portion 17 formed in this way is also provided in the second region 1c of the end face 1a of the negative electrode plate 1 (see FIG. 1A).
  • the entire end face 13a of the negative electrode lead 13 is melted. Therefore, even if burrs exist on the end surface 13a before arc welding, the burrs are also melted during welding, and as a result, sharp portions of the burrs disappear. Therefore, when a lithium ion battery is manufactured using the negative electrode according to the present embodiment, the separator is not damaged by burrs, and therefore, an electrical short circuit between the positive electrode and the negative electrode that may occur when the separator is damaged occurs. It becomes difficult.
  • region 1c among the melting parts 17 is 0.1 mm or more and 10 mm or less. If the width W is 0.1 mm or more, the melted portion 17 can provide the necessary bonding strength between the negative electrode current collector 10 and the negative electrode lead 13. Further, when burrs are present on the end face 13a of the negative electrode lead 13, the sharp portions of the burrs can be eliminated. When the width W is 10 mm or less, when the electrode group is formed by making the negative electrode and the positive electrode face each other, it is difficult to cause a loss in the facing area between the negative electrode and the positive electrode, and a high-capacity battery can be designed. Examples of methods for controlling the width W include a method of changing the moving distance of the welding torch, a method of changing the energy of the arc, and a method of changing the distance between the welding torch and the end face 1 a of the negative electrode plate 1.
  • the arc is continuously injected from the welding torch while moving the welding torch of the electrode for arc welding.
  • the present invention is not limited to this.
  • the arc may be intermittently ejected from the welding torch while moving the welding torch of the electrode for arc welding in the direction of the arrow 18 (see FIG. 2A).
  • the melting part 17 is intermittently formed in the longitudinal direction of the negative electrode plate 1.
  • a plasma welding method and a TIG (Tungsten Inert Gas) welding method are preferable.
  • the plasma welding method is particularly preferable. It is considered that the bonding strength and conductivity between the negative electrode current collector 10 and the negative electrode lead 13 by the melting part 17 improve as the elements are uniformly dispersed in the melting part 17.
  • Plasma welding and TIG welding are performed using a commercially available plasma welding machine and TIG welding machine, respectively.
  • Plasma welding is performed, for example, by appropriately selecting conditions such as welding current value, welding speed (moving speed of the welding torch), welding time, types of plasma gas and shield gas, and their flow rates. By selecting these conditions, it is possible to control the bonding strength and conductivity between the negative electrode current collector 10 and the negative electrode lead 13 by the melted portion 17 to be formed.
  • conditions such as welding current value, welding speed (moving speed of the welding torch), welding time, types of plasma gas and shield gas, and their flow rates.
  • the welding current value is, for example, 1A to 100A.
  • the sweep speed of the welding torch is, for example, 1 mm / second to 100 mm / second.
  • argon gas or the like is used as the plasma gas.
  • the plasma gas flow rate is, for example, 10 ml / min to 10 liters / min.
  • argon or hydrogen is used as the shielding gas.
  • the shield gas flow rate is, for example, 10 ml / min to 10 liters / min.
  • a part of the thin-film negative electrode active material layer 11 may remain in the melted portion 17 without being melted.
  • the melted portion 17 is formed by arc welding, even if the thin film negative electrode active material layer 11 remains in the melted portion 17, the joining of the negative electrode current collector 10 and the negative electrode lead 13 by the melted portion 17. The strength and continuity do not fall below the practical range.
  • lithium is occluded in the thin film negative electrode active material layer 11 between the first step and the second step. It is preferable to provide a step (hereinafter referred to as “lithium occlusion step”). Thereby, the uniform dispersibility of the alloy is further improved inside the melted part 17 obtained in the third step.
  • the contact area between the melted portion 17, the negative electrode current collector 10 and the negative electrode lead 13 becomes larger than when the lithium storage step is not provided.
  • the bonding strength and conductivity between the negative electrode current collector 10 and the negative electrode lead 13 by the melting part 17 are further improved.
  • the occlusion of lithium in the thin film negative electrode active material layer 11 is performed, for example, by vacuum deposition, an electrochemical method, sticking of lithium foil to the surface of the thin film negative electrode active material layer 11, or the like.
  • metallic lithium is attached to a target of a vacuum vapor deposition apparatus, and lithium is vacuum vapor deposited on the thin film negative electrode active material layer 11.
  • the occlusion amount of lithium is not particularly limited, it is preferable that the thin-film negative electrode active material layer 11 occlude lithium for an irreversible capacity.
  • FIG. 3 is a longitudinal sectional view schematically showing the configuration of the lithium ion battery according to the embodiment of the present invention.
  • the lithium ion battery 25 includes a negative electrode 28 obtained by the manufacturing method described above. Other configurations are the same as those of the conventional lithium ion battery.
  • the lithium ion battery 25 includes a wound electrode group 26, an upper insulating plate 30 and a lower insulating member that are respectively attached to both ends of the wound electrode group 26 in the longitudinal direction.
  • a plate 31 a battery case 32 in which the wound electrode group 26 is accommodated, a sealing plate 34 that seals an opening of the battery case 32, a positive electrode terminal 33 supported by the sealing plate 34, and a nonaqueous electrolyte (Not shown).
  • the wound electrode group 26 includes a strip-shaped positive electrode 27, a strip-shaped negative electrode 28, and a strip-shaped separator 29.
  • the wound electrode group 26 is obtained, for example, by winding a laminate in which a separator 29 is interposed between a positive electrode 27 and a negative electrode 28 with one end in the longitudinal direction as a winding axis. It is done.
  • the electrode group 26 is a wound type, but the present invention is not limited to this.
  • the electrode group 26 may be a stacked type in which a positive electrode 27 and a negative electrode 28 are stacked with a separator 29 interposed therebetween.
  • the positive electrode 27 includes a positive electrode plate 35 and a positive electrode lead 36.
  • the positive electrode plate 35 has a positive electrode current collector and a positive electrode active material layer.
  • a porous or non-porous conductive substrate made of a metal material such as stainless steel, titanium, aluminum, or an aluminum alloy is used.
  • porous conductive substrates include mesh bodies, net bodies, punching sheets, lath bodies, porous bodies, foams, and nonwoven fabrics.
  • Non-porous conductive substrates include foils and films.
  • the thickness of the conductive substrate is not particularly limited, but is usually 1 to 500 ⁇ m, preferably 1 to 50 ⁇ m, more preferably 10 to 30 ⁇ m.
  • the positive electrode active material layer is provided on both sides in the thickness direction of the positive electrode current collector, but is not limited thereto, and may be provided on one side in the thickness direction of the positive electrode current collector. Good.
  • the positive electrode active material layer includes a positive electrode active material, and may further include a conductive agent, a binder, and the like.
  • lithium-containing composite metal oxides As the positive electrode active material, lithium-containing composite metal oxides, olivine type lithium phosphate and the like are preferable.
  • the lithium-containing composite metal oxide is a metal oxide containing lithium and a transition metal element, or a metal oxide in which a part of the transition metal element in the metal oxide is substituted with a different element.
  • the transition metal element include Sc, Y, Mn, Fe, Co, Ni, Cu, and Cr, and Mn, Co, Ni, and the like are particularly preferable.
  • the different elements include Na, Mg, Zn, Al, Pb, Sb, and B, and Mg, Al, and the like are particularly preferable.
  • the transition metal element and the different element one kind of element may be used alone, or two or more kinds of elements may be used in combination.
  • the lithium-containing composite oxide Li l CoO 2, Li l NiO 2, Li l MnO 2, Li l Co m Ni 1-m O 2, Li l Co m A 1-m O n, Li l Ni 1- m A m O n , Li l Mn 2 O 4 , Li l Mn 2 ⁇ m A n O 4
  • A is Sc, Y, Mn, Fe, Co, Ni, Cu, Cr, Na, Mg, Zn, Al
  • olivine type lithium phosphate examples include LiXPO 4 and Li 2 XPO 4 F (X represents at least one element selected from the group consisting of Co, Ni, Mn, and Fe).
  • the molar ratio of lithium in the positive electrode active material described above is a value immediately after the production of the positive electrode active material, and the molar ratio increases or decreases due to charge / discharge.
  • the positive electrode active material constituting the positive electrode active material layer one type of active material may be used alone, or two or more types of active materials may be used in combination.
  • Examples of the conductive agent include graphites such as natural graphite and artificial graphite; carbon blacks such as acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; conductive properties such as carbon fiber and metal fiber. Fibers; metal powders such as aluminum; carbon fluoride and the like.
  • one type of conductive agent may be included alone, or two or more types of conductive agents may be included in combination.
  • Resin material is used for the binder.
  • Resin materials include polyvinylidene fluoride, polytetrafluoroethylene, polyhexafluoropropylene, polyethylene, polypropylene, polyamide, polyimide, polyamideimide, polyacrylonitrile, methyl polyacrylate, ethyl polyacrylate, polymethyl methacrylate, polymethacryl Examples include ethyl acid, polyvinyl pyrrolidone, styrene butadiene rubber, modified acrylic rubber, carboxymethyl cellulose, and copolymers containing two or more types of monomer compounds.
  • Examples of the monomer compound include tetrafluoroethylene, hexafluoropropylene, pentafluoropropylene, perfluoroalkyl vinyl ether, vinylidene fluoride, chlorotrifluoroethylene, ethylene, propylene, acrylic acid, and hexadiene.
  • one kind of binder may be contained alone, or two or more kinds of binders may be contained in combination.
  • the positive electrode active material layer is formed, for example, by applying a positive electrode mixture slurry on the surface of the positive electrode current collector, and drying and rolling the obtained coating film.
  • the positive electrode mixture slurry is prepared by dissolving or dispersing a positive electrode active material, a conductive agent, a binder, and the like in an organic solvent.
  • organic solvent dimethylformamide, dimethylacetamide, methylformamide, N-methyl-2-pyrrolidone, dimethylamine, acetone, cyclohexanone and the like are used.
  • the material of the positive electrode lead 36 is aluminum, an aluminum alloy, or the like.
  • the aluminum alloy include an aluminum-silicon alloy, an aluminum-iron alloy, an aluminum-copper alloy, an aluminum-manganese alloy, an aluminum-magnesium alloy, and an aluminum-zinc alloy.
  • the separator 29 is disposed so as to be interposed between the positive electrode 27 and the negative electrode 28.
  • a sheet having predetermined ion permeability, mechanical strength, insulation, and the like is used as the separator 29.
  • the separator 29 is preferably made of a porous sheet such as a microporous film, a woven fabric, or a non-woven fabric.
  • Various resin materials can be used as the material of the separator 29, but polyolefins such as polyethylene and polypropylene are particularly preferable in view of durability, shutdown function and the like.
  • the thickness of the separator 29 is usually 10 to 300 ⁇ m, preferably 10 to 30 ⁇ m, more preferably 10 to 25 ⁇ m.
  • the porosity of the separator 29 is preferably 30 to 70%, more preferably 35 to 60%. The porosity is the ratio of the total volume of the pores of the separator 29 to the volume of the separator 29.
  • the separator 29 is impregnated with a liquid nonaqueous electrolyte having lithium ion conductivity.
  • the liquid non-aqueous electrolyte contains a solute (supporting salt) and a non-aqueous solvent.
  • the liquid non-aqueous electrolyte may contain an additive.
  • Solutes include LiClO 4 , LiBF 4 , LiPF 6 , LiAlCl 4 , LiSbF 6 , LiSCN, LiCF 3 SO 3 , LiCF 3 CO 2 , LiAsF 6 , LiB 10 Cl 10 , lithium lower aliphatic carboxylate, LiCl, LiBr, Examples include LiI, LiBCl 4 , borate salts, and imide salts.
  • the solute is preferably dissolved in a non-aqueous solvent at a concentration of 0.5 to 2 mol / L.
  • Non-aqueous solvents include cyclic carbonates, chain carbonates, and cyclic carboxylic acid esters.
  • cyclic carbonate include propylene carbonate and ethylene carbonate.
  • chain carbonate include diethyl carbonate, ethyl methyl carbonate, dimethyl carbonate and the like.
  • cyclic carboxylic acid esters include ⁇ -butyrolactone and ⁇ -valerolactone.
  • the non-aqueous solvent one type of solvent may be used alone, or two or more types of solvents may be used in combination.
  • Additives include additives that improve charge and discharge efficiency such as fluorinated ethylene carbonate, vinylene carbonate, vinyl ethylene carbonate, and divinyl ethylene carbonate, and additives that inactivate batteries such as cyclohexylbenzene, biphenyl, and diphenyl ether.
  • the liquid non-aqueous electrolyte may contain one kind of additive alone, or may contain two or more kinds of additives in combination.
  • the upper insulating plate 30, the lower insulating plate 31, and the sealing plate 34 are produced by molding an electrically insulating material into a predetermined shape.
  • an electrically insulating material a resin material or a rubber material is preferable.
  • the battery case 32 is a bottomed cylindrical member having an opening at one end in the longitudinal direction.
  • the battery case 32 and the positive electrode terminal 33 are produced by molding a metal material such as iron or stainless steel into a predetermined shape.
  • the wound electrode group 26 is accommodated in the battery case 32 with the upper insulating plate 30 and the lower insulating plate 31 attached to both ends in the longitudinal direction.
  • the positive electrode lead 36 of the positive electrode 27 and the negative electrode lead 13 of the negative electrode 28 are respectively connected to predetermined locations.
  • a non-aqueous electrolyte is injected into the battery case 32.
  • a sealing plate 34 that supports the positive terminal 33 is inserted into the opening of the battery case 32, and the opening end of the battery case 32 is crimped toward the sealing plate 34. Thereby, the opening of the battery case 32 is sealed by the sealing plate 34. In this way, the lithium ion battery 25 is obtained.
  • the lithium ion battery 25 according to this embodiment has a high capacity and a high output by including the negative electrode 28, and is excellent in battery performance such as output characteristics and cycle characteristics.
  • the negative electrode plate 1 (negative electrode current collector 10) and the negative electrode lead 13 are firmly bonded, and an electrically good connection state is realized between them. Yes. Accordingly, the current collection performance of the negative electrode 28, the output characteristics of the battery, and the like are maintained at a high level over a long period of time. Therefore, the lithium ion battery 25 of this embodiment has a long service life.
  • the lithium ion battery 25 has a cylindrical shape, but is not limited thereto, and various forms can be adopted for the lithium ion battery 25. Specific examples thereof include a square battery, a flat battery, a coin battery, and a laminate film pack battery. Further, instead of the wound electrode group 26, a stacked electrode group, a flat electrode group, or the like may be used.
  • a sodium hydroxide aqueous solution having a concentration of 2 mol / liter is gradually added dropwise to the aqueous solution with stirring. As a result, these aqueous solutions were neutralized.
  • a ternary precipitate having a composition represented by Ni 0.85 Co 0.15 (OH) 2 was produced by a coprecipitation method. The precipitate was separated by filtration, washed with water, and then dried at 80 ° C. Thereby, a composite hydroxide was obtained.
  • the obtained composite hydroxide was heated in the atmosphere at 900 ° C. for 10 hours for heat treatment to obtain a composite oxide having a composition represented by Ni 0.85 Co 0.15 O 2 . Thereafter, lithium hydroxide monohydrate was added to the composite oxide so that the sum of the number of Ni and Co atoms was equal to the number of Li atoms. Then, heat treatment is performed by heating for 10 hours at 800 ° C. in air to obtain a lithium-nickel-containing composite metal oxide having a composition represented by LiNi 0.85 Co 0.15 O 2. In this way, a positive electrode active material in which the volume average particle size of the secondary particles was 10 ⁇ m was produced.
  • FIG. 4 is a side view schematically showing the configuration of the electron beam vacuum deposition apparatus 40.
  • the vacuum chamber 41 is a pressure-resistant container, and accommodates a transfer means 42, a gas supply means 48, a plasma generating means 49, silicon targets 50a and 50b, a shielding plate 51, and an electron beam generator (not shown). ing.
  • the conveying means 42 includes an unwinding roller 43, a can 44, a winding roller 45, and guide rollers 46 and 47.
  • the strip-shaped negative electrode current collector 10 is wound around the unwinding roller 43.
  • the negative electrode current collector 10 is conveyed via the guide roller 46, the can 44, and the guide roller 47, and then wound around the take-up roller 45.
  • silicon vapor is supplied to the surface of the negative electrode current collector 10.
  • the silicon vapor is deposited on the surface of the negative electrode current collector 10 by being cooled by a cooling means (not shown) provided inside the can 44. In this way, a thin-film negative electrode active material layer 11 that is a solid film is formed on the surface of the negative electrode current collector 10.
  • the silicon vapor is generated by irradiating the silicon targets 50a and 50b with an electron beam from an electron beam generator.
  • the gas supply means 48 supplies the source gas into the vacuum chamber 41.
  • the source gas is oxygen
  • a mixture of silicon vapor and oxygen is supplied to the surface of the negative electrode current collector 10.
  • the thin film negative electrode active material layer 11 contains a silicon oxide.
  • the source gas is not supplied from the gas supply means 48, only silicon vapor is supplied to the surface of the negative electrode current collector 10.
  • the thin film negative electrode active material layer 11 contains silicon.
  • the plasma generating means 49 converts the raw material gas into plasma. The position of the shielding plate 51 in the horizontal direction is adjusted according to the situation in which the thin film negative electrode active material layer 11 is formed on the surface of the negative electrode current collector 10.
  • a thin-film negative electrode active material layer 11 (silicon thin film) having a thickness of 5 ⁇ m was formed on both surfaces of the negative electrode current collector 10 using the electron beam vacuum deposition apparatus 40 under the following conditions.
  • a negative electrode plate 1 was prepared.
  • Negative electrode current collector Roughened electrolytic copper foil (Furukawa Electric Co., Ltd.) Winding speed of negative electrode current collector by take-up roller: 2 cm / min
  • Raw material gas Not supplied Silicon target: Silicon single crystal of purity 99.9999% (manufactured by Shin-Etsu Chemical Co., Ltd.)
  • Electron beam acceleration voltage -8 kV
  • Electron beam emission 300 mA
  • the obtained negative electrode plate 1 was cut into 58 mm ⁇ 210 mm.
  • This negative electrode plate 1 was fixed in a resistance heating vapor deposition apparatus (manufactured by ULVAC, Inc.) so that the tantalum board and the thin film negative electrode active material layer 11 face each other.
  • the tantalum board was loaded with lithium metal.
  • An argon atmosphere was introduced into the resistance heating vapor deposition apparatus, and a current of 50 A was applied to the tantalum board to deposit lithium on the thin film negative electrode active material layer 11.
  • the deposition time was 10 minutes. Thereby, lithium for the irreversible capacity stored at the time of first charge / discharge was supplemented to the thin film negative electrode active material layer 11.
  • the negative electrode lead 13 was joined to the produced negative electrode plate 1 as follows, and thereby the negative electrode 28 was produced.
  • the negative electrode lead 13 was produced by cutting a copper foil (tough pitch copper, manufactured by Hitachi Cable Ltd.) having a thickness of 0.1 mm so as to have a width of 5 mm and a length of 70 mm.
  • the negative electrode plate 1 and the negative electrode lead 13 were overlapped so that one end surface 1a in the width direction of the negative electrode plate 1 and one end surface 13a in the longitudinal direction of the negative electrode lead 13 were aligned on the same plane. These were clamped by the welding jig 14 shown in FIG. 2B so that the welding end face 16 composed of the end faces 1 a and 13 a was exposed from the welding jig 14.
  • the welding jig 14 was fixed to a single axis robot (manufactured by IAI Corporation).
  • the dimensions of the first plate 20 and the second plate 21 of the welding jig 14 were 100 mm ⁇ 40 mm ⁇ 10 mm, and both were made of copper.
  • the cross-sectional shapes of the notches formed in the first plate 20 and the second plate 21 are both tapered, and the cross-sectional dimensions of the notches are both along the end surface of the first plate 20 or the second plate 21.
  • the length in the direction was 0.5 mm, and the length in the direction along the mating surface of the first plate 20 or the second plate 21 was 0.5 mm.
  • a plasma welding machine (trade name: PW-50NR, manufactured by Koike Oxygen Co., Ltd.) was arranged so that the arc was irradiated perpendicularly to the welding end face 16. Then, while moving the welding torch of the plasma welding machine along the welding end surface 16, plasma gas was irradiated from the welding torch perpendicular to the welding end surface 16. At this time, with the center line of the negative electrode lead 13 as a reference, the positions separated by 3.5 mm before and after that were taken as the start point and the end point, respectively, and the welding torch was moved from the start point to the end point. In this way, the melted portion 17 was formed. Detailed conditions are as follows.
  • Electrode bar 1.0mm in diameter
  • Electrode nozzle 1.6mm in diameter
  • Torch distance 2.0mm
  • Torch sweep speed 30 mm / s Torch delivery width: 7mm
  • Plasma gas Argon
  • Plasma gas flow rate 100 (sccm)
  • Shield gas hydrogen, argon Shield gas flow rate (hydrogen): 500 (sccm)
  • the weld end face 16 was allowed to cool naturally after plasma welding. Thereafter, the weld end face 16 was observed with a laser microscope (trade name: VK9700, manufactured by Keyence Corporation). As a result, it was confirmed that the melted portion 17 was continuously formed on the weld end surface 16 from the first region 1b to the second region 1c of the end surface 1a of the negative electrode plate 1.
  • melting parts 17 was 3 mm.
  • a scanning electron microscope (3D real surface view) was equipped with an energy dispersive X-ray analyzer (trade name: Genesis XM2, manufactured by EDAX), and an elemental map of copper and silicon in the cross section of the melting portion 17 was examined.
  • an energy dispersive X-ray analyzer (trade name: Genesis XM2, manufactured by EDAX)
  • copper and silicon were present in almost the entire region of the cross section of the melted portion 17.
  • an energy dispersive X-ray analyzer Genesis XM2
  • copper was 95 mol% and silicon was 5 mol%. . From these results, it was found that silicon diffused in copper to form an alloy.
  • the cross section of the melted part 17 was qualitatively analyzed by a micro part X-ray diffractometer (trade name: RINT2500, manufactured by Rigaku Corporation). As a result, a copper peak and a Cu 5 Si peak were identified from the melted portion 17. Therefore, it has been found that the molten portion 17 contains a Cu 5 Si alloy.
  • the elemental map of lithium was examined with an Auger electron spectrometer (trade name: MODEL670, manufactured by ULVAC PHI) for the cross section of the melted portion.
  • an Auger electron spectrometer (trade name: MODEL670, manufactured by ULVAC PHI) for the cross section of the melted portion.
  • this active material layer is a layer formed from the silicon contained in the thin film negative electrode active material layer 11 that remains without melting.
  • the silicon layer is a layer formed from silicon contained in the thin film negative electrode active material layer 11 that is once melted but re-solidified without being alloyed.
  • a polyethylene microporous membrane (separator 29, trade name: Hypore, thickness 20 ⁇ m, manufactured by Asahi Kasei Co., Ltd.) is interposed between the produced positive electrode 27 and negative electrode 28 to laminate them. A laminate was produced. Thereafter, this laminate was wound to produce a wound electrode group 26.
  • the end of the positive electrode lead 36 was welded to the positive electrode terminal 33 made of stainless steel, and the end of the negative electrode lead 13 was connected to the bottom inner surface of the battery case 32 made of iron with a bottomed cylindrical shape.
  • the wound electrode group 26 was housed in a battery case 32 with a polyethylene upper insulating plate 30 and a lower insulating plate 31 attached to both ends in the longitudinal direction.
  • a non-aqueous electrolyte solution prepared by dissolving LiPF 6 at a concentration of 1.0 mol / L in a mixed solvent containing ethylene carbonate and ethyl methyl carbonate at a volume ratio of 1: 1 is prepared.
  • Case 32 was injected. Further, a polyethylene gasket and a sealing plate 34 were inserted into the opening of the battery case 32, and the opening end of the battery case was crimped toward the sealing plate 34. Thus, the opening of the battery case 32 was sealed with the sealing plate 34, and a cylindrical lithium ion battery was produced as Example 1.
  • Comparative Example 1 A negative electrode was produced with a torch feed width of 2 mm. Other configurations and production conditions were the same as those in Example 1. In this way, a cylindrical lithium ion battery was produced as Comparative Example 1.
  • the weld end face 16 was observed with a laser microscope (trade name: VK9700, manufactured by Keyence Corporation) after plasma welding. As a result, although the melted portion 17 having a width of 4 mm was formed, the end portion of the negative electrode lead 13 was hardly melted. In addition, a melted portion could not be confirmed in the second region 1 c of the end face 1 a of the negative electrode plate 1.
  • Comparative Example 2 The joining method of the negative electrode lead 13 to the negative electrode current collector 10 was changed from plasma welding to resistance welding to produce a negative electrode 28. Other configurations and production conditions were the same as those in Example 1. In this manner, a cylindrical lithium ion battery was produced as Comparative Example 2. The negative electrode was produced as follows.
  • the negative electrode plate 1 obtained in the same manner as in Example 1 and the copper negative electrode lead 13 are overlapped so that the end faces 1 a and 13 a are aligned on the same plane. Combined. Then, these negative electrode plate 1 and negative electrode lead 13 were sandwiched between electrode rods having a tip diameter of 2 mm. Thereafter, a resistance welding machine (manufactured by Miyachi Technos Co., Ltd.) was used and the current value was set to 1.3 kA to perform spot welding. In this way, a negative electrode 28 was produced.
  • a resistance welding machine manufactured by Miyachi Technos Co., Ltd.
  • Test Example 1 [Joint strength between negative electrode current collector and negative electrode lead]
  • the tensile strength of the negative electrode lead 13 with respect to the negative electrode current collector 10 was measured as follows. It was set as joining strength. Specifically, it is as follows.
  • the negative electrode lead 13 was cut so that the length of the negative electrode lead 13 was the same as the width of the negative electrode plate 1.
  • the negative electrode plate 1 was cut so that the length in the width direction of the negative electrode plate 1 was 30 mm from the end face 1a.
  • the bonding width d where the negative electrode current collector 10 and the negative electrode lead 13 were welded by the melting part 17 was measured.
  • the bonding width d is the width of the portion of the melting portion 17 provided in the first region 1b of the end face 1a of the negative electrode plate 1.
  • the negative electrode lead 13 was turned up in the direction of the arrow 66 by raising the negative electrode lead 13 from the negative electrode plate 1.
  • the tensile strength was measured by the measuring method shown in FIG. Specifically, a universal testing machine 70 manufactured by Shimadzu Corporation is prepared, and the lower fixing jig 71 is opposite to the end of the negative electrode plate 1 opposite to the end where the melted portion 17 is formed. The ends were fixed. Further, the upper fixing jig 72 was fixed by sandwiching the end portion of the negative electrode lead 13 opposite to the end portion where the melted portion 17 is formed.
  • the negative electrode lead 13 was pulled up with respect to the negative electrode plate 1 by moving the upper fixing jig 72 in the direction of the arrow 73 at a speed of 5 mm / min at a room temperature of 25 ° C. And the tensile strength (N) when the junction part (The melted part 17 in Example 1 and Comparative Example 1) of the negative electrode plate 1 and the negative electrode lead 13 fractured was measured.
  • the tensile strength (N / mm) per 1 mm of the bonding width was determined from the measured value of the tensile strength and the measured value of the bonding width d. The results are shown in Table 1.
  • the junction resistance between the negative electrode current collector 10 and the negative electrode lead 13 was measured as follows. First, the thin film negative electrode active material layer 11 was peeled off at a position near the negative electrode lead 13 using sandpaper. Next, as the junction resistance, the resistance between the exposed portion of the negative electrode current collector 10 and the negative electrode lead was measured using a milliohm meter (trade name: milliohm high tester 3540, manufactured by Hioki Electric Co., Ltd.). . The results are shown in Table 1.
  • the negative electrode current collector 10 and the negative electrode lead 13 are bonded to each other by the melting portion 17 as in Example 1 and Comparative Example 1 to thereby connect the negative electrode current collector 10 and the negative electrode lead 13 to each other. It was found that high bonding strength and electrical conductivity can be obtained. Further, no defective cells were confirmed in Example 1, whereas defective cells were confirmed in Comparative Example 1. From this, it was found that it is important that a part of the melting portion 17 is also provided in the second region 1c of the end face 1a of the negative electrode plate 1.
  • Each lithium ion battery was charged at a constant current of 1C rate (1C is a current value that can use up the entire battery capacity in 1 hour) until the battery voltage reached 4.2V. After the battery voltage reached 4.2V, each battery was charged at a constant voltage of 4.2V until the current value reached 0.05C. Next, after resting for 20 minutes, the charged battery was discharged at a constant rate of 1C rate until the battery voltage reached 2.5V. Such charge and discharge was repeated 100 cycles.
  • the ratio of the total discharge capacity at the 100th cycle to the total discharge capacity at the first cycle was determined as a percentage value.
  • An average value of the obtained values was calculated and used as a capacity retention rate. The results are shown in Table 2.
  • the lithium ion batteries of Example 1 and Comparative Example 1 had a high capacity retention rate and good cycle characteristics.
  • the lithium ion battery of Example 1 is preferable because it has a higher capacity retention rate than Comparative Example 1.
  • the resistance was infinite in one of the three lithium ion batteries. Therefore, when the lithium ion battery was disassembled and observed, it was found that the junction between the negative electrode current collector 10 and the negative electrode lead 13 was broken.
  • the lithium ion battery of Comparative Example 2 had an infinite resistance and could not be energized. Thus, when the lithium ion battery of Comparative Example 2 was disassembled and observed, it was found that the junction was broken as in Comparative Example 1.
  • the negative electrode according to the present invention is suitable as a negative electrode for a lithium ion battery.
  • the lithium ion battery according to the present invention can be used in the same applications as conventional lithium ion batteries, and is particularly useful as a power source for portable electronic devices. Examples of portable electronic devices include personal computers, mobile phones, mobile devices, personal digital assistants (PDAs), portable game devices, and video cameras.
  • the lithium ion battery according to the present invention is a main power source and auxiliary power source for hybrid electric vehicles, electric vehicles, fuel cell vehicles, etc .; power sources for driving electric tools, cleaners, robots, etc .; power sources for plug-in HEVs, etc. Is expected to be used.
  • Negative electrode plate 1a End surface 1b 1st area
  • Negative electrode collector 11 Thin film-like negative electrode active material layer 13

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Connection Of Batteries Or Terminals (AREA)
  • Secondary Cells (AREA)
  • Cell Electrode Carriers And Collectors (AREA)

Abstract

L'invention concerne un électrode négative pour batterie à lithium-ion, dans laquelle la liaison entre un collecteur d'électrode négative et un conducteur d'électrode négative est difficile à rompre ; et une batterie à lithium-ion ayant une capacité et une puissance en sortie élevées. L'électrode négative de la batterie à lithium-ion de la présente invention comprend une plaque d'électrode négative, le conducteur d'électrode négative et une section fondue. La plaque d'électrode négative a un collecteur, et une couche de substance active d'électrode négative à film mince formée sur la surface du collecteur ; la couche de substance active d'électrode négative à film mince comprenant une substance active d'alliage. La section fondue est formée en ce que la surface d'extrémité de la plaque d'électrode négative et la surface d'extrémité du conducteur d'électrode négative sont interposées entre eux ; et qu'elle soude également le conducteur d'électrode négative au collecteur. Dans la surface d'extrémité de la plaque d'électrode négative on trouve une première zone comprenant la surface d'extrémité de la section de la plaque d'électrode négative faisant face au conducteur d'électrode négative, et une deuxième zone comprenant la surface d'extrémité de la section de la plaque d'électrode négative ne faisant pas face au conducteur d'électrode négative. Une partie de la section fondue est formée dans la première zone, le reste de la section fondue étant formé dans une partie de la deuxième zone. La largeur de la section fondue est donc plus grande que la largeur du conducteur d'électrode négative.
PCT/JP2012/007250 2011-11-28 2012-11-12 Électrode négative pour batterie à lithium-ion et batterie à lithium-ion WO2013080459A1 (fr)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111293268A (zh) * 2018-12-10 2020-06-16 丰田自动车株式会社 电池
CN112470323A (zh) * 2018-07-30 2021-03-09 松下知识产权经营株式会社 锂二次电池
CN113097426A (zh) * 2021-03-29 2021-07-09 宁德新能源科技有限公司 电化学装置和电子装置
WO2022235159A1 (fr) 2021-05-04 2022-11-10 Leydenjar Technologies B.V. Ensemble électrode pour une batterie ayant une soudure par ultrasons, procédé de fabrication et utilisation de l'ensemble
NL2028136B1 (en) 2021-05-04 2022-11-10 Leydenjar Tech B V Method for joining an electrode tab to a current collector using ultrasonic welding, an electrode assembly for a battery, and use of the assembly

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109888161B (zh) * 2018-09-11 2022-03-29 拓迪化学(上海)有限公司 一种电极极片及电池电芯

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003109575A (ja) * 2001-09-28 2003-04-11 Sanyo Electric Co Ltd 電 池
WO2010041399A1 (fr) * 2008-10-08 2010-04-15 パナソニック株式会社 Électrode négative et son procédé de production, et accumulateur secondaire à électrolyte non aqueux
JP2010157484A (ja) * 2008-06-25 2010-07-15 Panasonic Corp 非水電解質二次電池用電極構造体、その製造方法、および非水電解質二次電池
WO2011016200A1 (fr) * 2009-08-05 2011-02-10 パナソニック株式会社 Batterie hermétiquement fermée et son procédé de fabrication
JP2011029026A (ja) * 2009-07-27 2011-02-10 Panasonic Corp 負極およびその製造方法ならびに非水電解質二次電池
JP2011100642A (ja) * 2009-11-06 2011-05-19 Panasonic Corp リチウムイオン電池用負極の製造方法及びリチウムイオン電池

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003109575A (ja) * 2001-09-28 2003-04-11 Sanyo Electric Co Ltd 電 池
JP2010157484A (ja) * 2008-06-25 2010-07-15 Panasonic Corp 非水電解質二次電池用電極構造体、その製造方法、および非水電解質二次電池
WO2010041399A1 (fr) * 2008-10-08 2010-04-15 パナソニック株式会社 Électrode négative et son procédé de production, et accumulateur secondaire à électrolyte non aqueux
JP2011029026A (ja) * 2009-07-27 2011-02-10 Panasonic Corp 負極およびその製造方法ならびに非水電解質二次電池
WO2011016200A1 (fr) * 2009-08-05 2011-02-10 パナソニック株式会社 Batterie hermétiquement fermée et son procédé de fabrication
JP2011100642A (ja) * 2009-11-06 2011-05-19 Panasonic Corp リチウムイオン電池用負極の製造方法及びリチウムイオン電池

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112470323A (zh) * 2018-07-30 2021-03-09 松下知识产权经营株式会社 锂二次电池
CN112470323B (zh) * 2018-07-30 2024-02-23 松下知识产权经营株式会社 锂二次电池
CN111293268A (zh) * 2018-12-10 2020-06-16 丰田自动车株式会社 电池
CN111293268B (zh) * 2018-12-10 2022-03-15 丰田自动车株式会社 电池
CN113097426A (zh) * 2021-03-29 2021-07-09 宁德新能源科技有限公司 电化学装置和电子装置
US12002964B2 (en) 2021-03-29 2024-06-04 Ningde Amperex Technology Limited Electrochemical device and electronic device
WO2022235159A1 (fr) 2021-05-04 2022-11-10 Leydenjar Technologies B.V. Ensemble électrode pour une batterie ayant une soudure par ultrasons, procédé de fabrication et utilisation de l'ensemble
NL2028136B1 (en) 2021-05-04 2022-11-10 Leydenjar Tech B V Method for joining an electrode tab to a current collector using ultrasonic welding, an electrode assembly for a battery, and use of the assembly
WO2022235158A1 (fr) 2021-05-04 2022-11-10 Leydenjar Technologies B.V. Procédé d'assemblage d'une languette d'électrode à un collecteur de courant par soudage par ultrasons, ensemble électrode pour batterie et utilisation de l'ensemble
NL2028135B1 (en) 2021-05-04 2022-11-10 Leydenjar Tech B V Electrode assembly for a battery having an ultrasonic weld, method for manufacture and use of the assembly

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