JP2015035249A - Negative electrode for lithium ion battery and lithium ion battery - Google Patents

Negative electrode for lithium ion battery and lithium ion battery Download PDF

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JP2015035249A
JP2015035249A JP2011258966A JP2011258966A JP2015035249A JP 2015035249 A JP2015035249 A JP 2015035249A JP 2011258966 A JP2011258966 A JP 2011258966A JP 2011258966 A JP2011258966 A JP 2011258966A JP 2015035249 A JP2015035249 A JP 2015035249A
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negative electrode
active material
current collector
electrode lead
lead
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古結　康隆
Yasutaka Furuyui
康隆 古結
心 原口
Shin Haraguchi
心 原口
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Panasonic Corp
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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

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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

PROBLEM TO BE SOLVED: To provide a negative electrode for lithium ion battery including a negative electrode active material layer of a thin film containing an alloy-based active material capable of improving connection reliability between a negative electrode collector and a negative electrode lead.SOLUTION: The negative electrode for lithium ion battery includes: a negative electrode plate which contains a negative electrode collector and an alloy-based active material; and a fusion part which includes a negative electrode lead connected to the negative electrode plate and connect the end of the negative electrode plate and the end of the negative electrode lead. The fusion part has a fusion area wider than the width of the negative electrode lead. At least a part of the end of the negative electrode plate at the side not opposite to the negative electrode lead is also provided with a fusion part.

Description

本発明は、リチウムイオン電池用負極及びリチウムイオン電池に関する。さらに詳しくは、合金系活物質を含有するリチウムイオン電池用負極における接合部の改良と、負極集電体と負極リードとの接合方法の改良に関する。   The present invention relates to a negative electrode for a lithium ion battery and a lithium ion battery. More specifically, the present invention relates to an improvement in a joining portion in a negative electrode for a lithium ion battery containing an alloy-based active material and an improvement in a joining method between a negative electrode current collector and a negative electrode lead.

リチウムイオン電池は、高容量及び高エネルギー密度を有し、小型化及び軽量化が容易なことから、電子機器等の電源として広く利用されている。電子機器には、携帯電話、携帯情報端末（Personal Digital Assistant、ＰＤＡ）、ノート型パーソナルコンピュータ、ビデオカメラ、携帯ゲーム機等がある。代表的なリチウムイオン電池は、リチウムコバルト複合酸化物を含有する正極と、黒鉛を含有する負極と、ポリオレフィン製セパレータと、を備える。   Lithium ion batteries are widely used as power sources for electronic devices and the like because they have a high capacity and a high energy density, and can be easily reduced 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.

正極及び負極は、それぞれ、集電体と活物質層とリードとからなる。活物質層は集電体表面に形成される。リードは、活物質層が形成されていない集電体露出部に溶接される。リードの溶接には、抵抗溶接や超音波溶接が利用されている。集電体露出部は、集電体表面に間隔を空けて活物質層を形成するか、又は集電体表面に活物質層を形成した後、活物質層の一部を除去することにより形成される。   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 current collector surface. The lead is welded to the exposed portion of the current collector where the active material layer is not formed. Resistance welding and ultrasonic welding are used for lead welding. The current collector exposed portion is formed by forming an active material layer with a space on the current collector surface or by removing a part of the active material layer after forming the active material layer on the current collector surface. Is done.

最近では電子機器の多機能化が進み、その電力消費量が増大している。その一方で、一度の充電で連続して使用できる時間の延長が望まれている。このため、リチウムイオン電池のさらなる高容量化が必要になり、黒鉛よりも高容量である合金系活物質の開発が盛んに行われている。代表的な合金系活物質には、珪素、珪素酸化物等の珪素系活物質がある。   Recently, electronic devices have become more multifunctional, and their power consumption is increasing. On the other hand, it is desired to extend the time that can be used continuously by one charge. For this reason, it is necessary to further increase the capacity of the lithium ion battery, and development of an alloy-based active material having a capacity higher than that of graphite has been actively performed. Typical alloy-based active materials include silicon-based active materials such as silicon and silicon oxide.

合金系活物質を含有する負極は、一般的には、負極集電体と、負極集電体表面に気相法により形成される合金系活物質の薄膜（以下において「薄膜状負極活物質層」とすることがある）と、を備える。   A negative electrode containing an alloy-based active material generally includes 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 a “thin film-like negative electrode active material layer”). ”).

薄膜状負極活物質層が形成された負極集電体に、負極リードを接合する方法が種々提案されている。   Various methods for joining a negative electrode lead to a negative electrode current collector on which a thin film negative electrode active material layer is formed have been proposed.

特許文献１は、負極板と負極リードとの積層体にレーザを照射することにより、積層体を厚さ方向に貫通する連通孔を形成した負極を開示している。積層体にレーザを照射すると、連通孔の内部表面に存在する負極集電体と負極リードとが溶融して接触することにより、負極集電体と負極リードとが接続される。   Patent Document 1 discloses a negative electrode in which a communication hole penetrating the laminated body in the thickness direction is formed by irradiating a laminated body of a negative electrode plate and a negative electrode lead with a laser. When the laminated body is irradiated with laser, the negative electrode current collector and the negative electrode lead existing on the inner surface of the communication hole are melted and brought into contact with each other, thereby connecting the negative electrode current collector and the negative electrode lead.

しかしながら、負極集電体と負極リードとの接続部分には、合金系活物質の粒子が含まれている。合金系活物質の粒子は、レーザ照射により、薄膜状負極活物質層から流出したものである。合金系活物質は融点が高いので、レーザを照射しただけでは、溶融しにくい。したがって、接続部分の接合強度は低い。また、合金系活物質は電気抵抗が大きいので、接続部分に合金系活物質の粒子が存在することにより、接続部分の導通性が低下しやすい。   However, the connection portion between the negative electrode current collector and the negative electrode lead contains particles of an alloy-based active material. The alloy-based active material particles flow out of the thin-film negative electrode active material layer by laser irradiation. Since the alloy-based active material has a high melting point, it is difficult to melt only by laser irradiation. Therefore, the joint strength of the connection portion is low. Further, since the alloy-based active material has a large electric resistance, the presence of the alloy-based active material particles in the connection portion tends to lower the conductivity of the connection portion.

特許文献２は、合金系活物質を含有する薄膜状負極活物質層の表面に、銅、銅合金又は銅のクラッド材からなる負極リードを抵抗溶接により接合した負極を開示している。抵抗溶接では、負極集電体又は負極リードが局所的に溶融することがあるが、薄膜状負極活物
質層には電流がほとんど流れないので、薄膜状負極活物質層は溶融しない。このため、負極集電体と負極リードとは十分に接合しない。 Patent Document 2 discloses a negative electrode 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. In resistance welding, the negative electrode current collector or the negative electrode lead may locally melt. However, since a current hardly flows through the thin film negative electrode active material layer, the thin film negative electrode active material layer does not melt. For this reason, the negative electrode current collector and the negative electrode lead are not sufficiently bonded.

ところで、合金系二次電池に用いられる負極として、結着剤を用いた活物質層を形成する代わりに、銅箔等からなる集電体の表面に真空蒸着等により珪素系活物を被着させた珪素系負極が知られている。このような珪素系負極においては、集電体にリードを接続することが煩雑であるという問題があった。詳しくは、従来の負極のような集電体が露出したリード接続部を形成するためには、例えば、真空蒸着等の際にリード接続部の形成領域をマスクすることにより、その領域に珪素系活物質が蒸着されないようにする必要があった。このような、マスク作業は、工程上非常に煩雑になる。   By the way, as a negative electrode used in an alloy-based secondary battery, instead of forming an active material layer using a binder, a silicon-based active material is deposited on the surface of a current collector made of copper foil or the like by vacuum deposition or the like. Known silicon-based negative electrodes are known. In such a silicon-based negative electrode, there is a problem that it is complicated to connect the lead to the current collector. Specifically, in order to form a lead connection portion where a current collector such as a conventional negative electrode is exposed, for example, by masking the formation region of the lead connection portion during vacuum deposition or the like, a silicon-based region is formed in the region. It was necessary to prevent the active material from being deposited. Such a mask operation becomes very complicated in the process.

このような問題に対し、本発明者らは、珪素系活物質等からなる活物質層が両側表面に設けられた集電体と、ニッケル、ニッケル合金、銅及び銅合金よりなる群から選ばれる少なくとも１種を含有するリードとを、アーク溶接により接続する方法を提案した（特許文献３参照）。詳しくは、集電体の表面に形成された活物質層にリードの一部分を重ね、重ね合わせた部分をアーク溶接することにより、集電体とリードとの間に珪素系合金層が形成され、集電体とリードとが導通性良く接続される。このような珪素系合金層は、活物質層が集電体及びリードのそれぞれ一部と共に溶融し、再凝固することにより形成される。   For such problems, the present inventors are selected from the group consisting of a current collector provided with active material layers made of silicon-based active material or the like on both side surfaces, and nickel, nickel alloy, copper, and copper alloy. A method of connecting a lead containing at least one kind by arc welding has been proposed (see Patent Document 3). Specifically, by overlapping a part of the lead on the active material layer formed on the surface of the current collector and arc welding the overlapped part, a silicon-based alloy layer is formed between the current collector and the lead, The current collector and the lead are connected with good conductivity. Such a silicon-based alloy layer is formed by melting and resolidifying the active material layer together with a part of each of the current collector and the lead.

図７（ａ）は、アーク溶接による珪素系負極板の接続状態を模式的に示す上面図であり、図７（ｂ）は、アーク溶接による珪素系負極板の接続状態を模式的に示す側面図である。珪素系負極板１と負極リード１３とをアーク溶接することにより、珪素系負極板１の負極集電体１０と負極リード１３とが溶融部１７を介して接続されている。このように集電体の表面に形成された珪素系活物質層にリードの一部分を重ね、重ね合わせた部分をアーク溶接することにより、集電体の露出部を形成することなく溶接ができるために工業的に有利になる。   FIG. 7A is a top view schematically showing the connection state of the silicon-based negative electrode plate by arc welding, and FIG. 7B is a side view schematically showing the connection state of the silicon-based negative electrode plate by arc welding. FIG. By arc welding the silicon-based negative electrode plate 1 and the negative electrode lead 13, the negative electrode current collector 10 and the negative electrode lead 13 of the silicon-based negative electrode plate 1 are connected via the melting portion 17. In this way, by overlapping a part of the lead on the silicon-based active material layer formed on the surface of the current collector and arc welding the overlapped portion, welding can be performed without forming the exposed portion of the current collector. It becomes industrially advantageous.

特開２００７−２１４０８６号公報JP 2007-214086 A 特開２００７−１１５４２１号公報JP 2007-115421 A 国際公開第２０１０／０４１３９９号International Publication No. 2010/041399

特許文献３に開示された技術によれば、珪素系負極にリードを溶接することが容易になる。しかしながら、本発明者らは、次のような新たな課題を見出した。   According to the technique disclosed in Patent Document 3, it becomes easy to weld a lead to a silicon-based negative electrode. However, the present inventors have found the following new problem.

すなわち、珪素系負極において、集電体とリードを重ね合わせた領域にアーク溶接するが、重ね合わせのない領域を溶融させないために、リードの幅よりもアークを照射する面積を狭くする。この結果、溶融部の幅がリードの幅より狭くなり十分な接合強度が得られず、製造プロセスにおいてリードにかかる応力や、電池作製後にリードにかかる応力が接合部に集中しやすく、接合部が破断する不具合が起こりやすくなる。   That is, in the silicon-based negative electrode, arc welding is performed on the region where the current collector and the lead are overlapped. However, in order not to melt the region where there is no overlap, the area irradiated with the arc is narrower than the width of the lead. As a result, the width of the melted portion becomes narrower than the width of the lead and sufficient bonding strength cannot be obtained, and stress applied to the lead in the manufacturing process and stress applied to the lead after manufacturing the battery are easily concentrated on the bonded portion. Failure to break easily occurs.

さらに、負極リードの端部は切断時にバリが発生しやすいため、正極と負極とセパレータを重ねて電極群を形成時に、負極リードのバリがセパレータを損傷して短絡する不具合が起こりやすくなる。   Further, since the end portion of the negative electrode lead is likely to generate burrs when cut, when the electrode group is formed by stacking the positive electrode, the negative electrode, and the separator, a problem that the burrs of the negative electrode lead damage the separator and short-circuit easily occurs.

本発明は、合金系負極活物質を利用するリチウムイオン電池において、負極集電体と負極リードとが破断する不具合を抑制できる負極及び当該負極を含み高容量及び高出力を有
するリチウムイオン電池を提供することを目的とする。 The present invention provides a lithium ion battery using an alloy-based negative electrode active material, a negative electrode capable of suppressing the failure of the negative electrode current collector and the negative electrode lead, and a lithium ion battery including the negative electrode and having a high capacity and a high output. The purpose is to do.

本発明のリチウムイオン電池用負極は、集電体及び集電体の表面に形成される薄膜状負極活物質を備え、薄膜状負極活物質層が合金系活物質を含有する負極板と、負極板に接続される負極リードと、負極板の端面と負極リードの端面との間に介在しこれらを溶接する溶融部を有するリチウムイオン電池用負極であって、溶融部は、負極リードの幅より溶融領域が広く、負極リードが対向しない負極板の端面の少なくとも一部にも溶融部が設けられているリチウムイオン電池用負極に係わる。   A negative electrode for a lithium ion battery according to the present invention includes a current collector and a thin-film negative electrode active material formed on a surface of the current collector, a thin-film negative electrode active material layer containing an alloy-based active material, and a negative electrode A negative electrode lead for a lithium ion battery having a negative electrode lead connected to the plate and a melting part interposed between the end face of the negative electrode plate and the end face of the negative electrode lead and welding them, the melting part being smaller than the width of the negative electrode lead The present invention relates to a negative electrode for a lithium ion battery in which a melting region is wide and at least a part of an end face of a negative electrode plate where a negative electrode lead does not face is provided with a melting portion.

本発明のリチウムイオン電池用負極は、負極板と負極リードとを接合する溶融部を有し、溶融部が負極リードの幅より広く、負極リードが対向しない負極板の端面の少なくとも一部にも溶融部が設けられることにより、負極リードの幅全域を負極板に接合することができる。これより負極リードの破断を抑制することができる。   The negative electrode for a lithium ion battery according to the present invention has a melting part for joining the negative electrode plate and the negative electrode lead, the melting part is wider than the width of the negative electrode lead, and at least part of the end face of the negative electrode plate where the negative electrode lead does not face By providing the melting portion, the entire width of the negative electrode lead can be bonded to the negative electrode plate. Thereby, the breakage of the negative electrode lead can be suppressed.

また、負極リードの端部に生成しやすいバリが、負極リードの幅全域を溶融させることによりバリも溶融して鋭利な部分が消失するため、セパレータを損傷することなく、短絡の不具合を抑制することができる。   In addition, the burr that is likely to be generated at the end of the negative electrode lead melts the entire width of the negative electrode lead, so that the burr is melted and the sharp part disappears. Therefore, the short circuit failure is suppressed without damaging the separator. be able to.

さらに、負極リードの両端に隣接する、負極リードに対向していない負極板の端部に溶融部を形成することによって、活物質の珪素が銅に拡散し合金化することで強度を高めることができる。このため、負極リードと負極板接合部付近の負極板に亀裂が生じる不具合を抑制することができる。   Further, by forming a melted portion at the end of the negative electrode plate adjacent to both ends of the negative electrode lead and not facing the negative electrode lead, the active material silicon diffuses into copper and is alloyed to increase the strength. it can. For this reason, the malfunction which a crack arises in the negative electrode plate of the negative electrode lead and the negative electrode plate vicinity vicinity can be suppressed.

また、本発明のリチウムイオン電池は、本発明の負極を用いたリチウムイオン電池は、高容量及び高出力を有し、サイクル特性等の電池性能に優れている。   Moreover, the lithium ion battery of the present invention is a lithium ion battery using the negative electrode of the present invention, has a high capacity and a high output, and is excellent in battery performance such as cycle characteristics.

（ａ）本発明の実施形態である負極の要部の構成を簡略化して示す上面図（ｂ）本発明の実施形態である負極の要部の構成を簡略化して示す側面図(A) The top view which simplifies and shows the structure of the principal part of the negative electrode which is embodiment of this invention (b) The side view which simplifies and shows the structure of the principal part of the negative electrode which is embodiment of this invention （ａ）本発明の負極の製造方法で第３工程を説明する上面図（ｂ）本発明の負極の製造方法で第３工程を説明する断面図(A) Top view explaining 3rd process with the manufacturing method of the negative electrode of this invention (b) Sectional drawing explaining 3rd process with the manufacturing method of the negative electrode of this invention 本発明の別の実施形態であるリチウムイオン電池の構成を模式的に示す縦断面図The longitudinal cross-sectional view which shows typically the structure of the lithium ion battery which is another embodiment of this invention. 電子ビーム式蒸着装置の構成を模式的に示す側面図Side view schematically showing the configuration of an electron beam evaporation system （ａ）負極リードの負極集電体に対する引張強度を測定するための試料の一作製方法を模式的に示す斜視図（ｂ）負極リードの負極集電体に対する引張強度を測定するための試料の一作製方法を模式的に示す斜視図(A) Perspective view schematically showing a method for preparing a sample for measuring the tensile strength of the negative electrode lead with respect to the negative electrode current collector. (B) Sample of the sample for measuring the tensile strength of the negative electrode lead with respect to the negative electrode current collector. Perspective view schematically showing one manufacturing method 負極リードの負極集電体に対する引張強度の測定方法を模式的に示す斜視図The perspective view which shows typically the measuring method of the tensile strength with respect to the negative electrode collector of a negative electrode lead （ａ）従来の負極の要部の構成を簡略化して示す上面図（ｂ）従来の負極の要部の構成を簡略化して示す側面図(A) Top view showing simplified configuration of main part of conventional negative electrode (b) Side view showing simplified configuration of main part of conventional negative electrode

本発明者らは、上記課題を解決するための研究過程において、特許文献２のように、合金系活物質を含有する薄膜状負極活物質層を介して負極集電体と負極リードとを接合する構成に着目した。そして、負極集電体と薄膜状負極活物質層とを備える負極板と、特定の材質を有する負極リードとを、アーク溶接により接合する新規な方法を見出した。この方法によれば、負極集電体と負極リードとが溶融するだけでなく、薄膜状負極活物質層に含有される合金系活物質が溶融して合金層が形成されることにより、負極集電体と負極リー
ドとを、導通性良くかつ強固に接合できることを見出した。 In the research process for solving the above problems, the present inventors joined the negative electrode current collector and the negative electrode lead through a thin film negative electrode active material layer containing an alloy-based active material as in Patent Document 2. Focused on the configuration to do. And the novel method of joining a negative electrode plate provided with a negative electrode collector and a thin film-like negative electrode active material layer, and the negative electrode lead which has a specific material by arc welding was discovered. According to this method, not only the negative electrode current collector and the negative electrode lead are melted, but also the alloy-based active material contained in the thin film negative electrode active material layer is melted to form an alloy layer. It has been found that the electrical conductor and the negative electrode lead can be joined firmly with good electrical conductivity.

このアーク溶接により接合する方法では、薄膜状負極活物質層の表面と負極リードの表面とが重なり、負極板の端面と負極リードの端面とからなる平坦な溶接端面が露出するように、負極板と負極リードとを溶接治具により挟持する。そして、溶接端面に対してアーク放電を行うことにより、負極集電体と負極リードとの間に合金層の溶融部が形成される。   In this method of joining by arc welding, the surface of the thin film negative electrode active material layer and the surface of the negative electrode lead are overlapped, and the flat weld end surface composed of the end surface of the negative electrode plate and the end surface of the negative electrode lead is exposed. And the negative electrode lead are sandwiched by a welding jig. Then, by performing arc discharge on the weld end face, a molten portion of the alloy layer is formed between the negative electrode current collector and the negative electrode lead.

しかしながら、このアーク溶接により接合する方法では、負極リードの幅よりも溶融領域の幅が狭いため、負極リードに引っ張り応力やひねり、変角させる応力が印加されると溶融端部に応力が集中し、負極リードが破断する不具合が起こりやすくなる。   However, in this method of joining by arc welding, since the width of the melting region is narrower than the width of the negative electrode lead, when stress that causes tensile stress, twisting, or turning is applied to the negative electrode lead, the stress concentrates on the melting end. The problem that the negative electrode lead breaks easily occurs.

また、負極リードの切断加工時には端部にバリが生成しやすいため、負極リードの端部にバリが存在した状態で電極群を作製した場合に、バリがセパレータを損傷させて内部短絡が発生するなど、不具合が起こりやすくなる。   In addition, burrs are likely to be generated at the end of the negative electrode lead when cutting, so when an electrode group is fabricated with burrs present at the end of the negative electrode lead, the burrs damage the separator and cause an internal short circuit. Etc., it becomes easier to cause problems.

本発明者らは、負極リードの接続信頼性について、鋭意研究を重ねた。その結果、負極リードの幅よりも広くアーク溶接を施し、リード幅全域を溶融接続させて接続強度を確保しつつ、負極リードが対向していない負極板を必要以上に溶融させない接合条件を見出した。   The inventors of the present invention have made extensive studies on the connection reliability of the negative electrode lead. As a result, arc welding was performed wider than the width of the negative electrode lead, and the bonding conditions were found such that the negative electrode plate not facing the negative electrode lead was not melted more than necessary while the entire lead width was fused and secured to ensure connection strength. .

以下、図１を用いて本発明の実施形態について詳しく説明する。   Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG.

負極集電体１０には、リチウムイオン電池の分野で常用される無孔の導電性基板を使用できる。無孔の導電性基板の形態には、箔、シート、フィルム等がある。導電性基板の材質には、ステンレス鋼、チタン、ニッケル、銅、銅合金等がある。導電性基板の厚さは、通常は１〜５００μｍ、好ましくは１〜５０μｍ、より好ましくは１０〜４０μｍ、さらに好ましくは１０〜３０μｍである。   As the negative electrode current collector 10, a nonporous conductive substrate commonly used in the field of lithium ion batteries can be used. 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 μm, preferably 1 to 50 μm, more preferably 10 to 40 μm, and still more preferably 10 to 30 μm.

薄膜状負極活物質層１１は、合金系活物質を含有する。薄膜状負極活物質層１１は、合金系活物質とともに、その特性を損なわない範囲で、合金系活物質以外の公知の負極活物質、添加物等を含んでいてもよい。好ましい形態の薄膜状負極活物質層１１は、合金系活物質を含有しかつ膜厚が３〜５０μｍである非晶質又は低結晶性の薄膜である。   The thin film negative electrode active material layer 11 contains an alloy-based active material. The thin film negative electrode active material layer 11 may contain a known negative electrode active material, additives, and the like other than the alloy active material, as long as the characteristics thereof are not impaired, together with the alloy active material. The thin film negative electrode active material layer 11 in a preferred form is an amorphous or low crystalline thin film containing an alloy-based active material and having a thickness of 3 to 50 μm.

合金系活物質は、負極電位下で、充電時にリチウムと合金化することによりリチウムを吸蔵し、かつ放電時にリチウムを放出する。合金系活物質としては特に制限されず、公知のものを使用できるが、珪素系活物質及び錫系活物質が好ましく、珪素系活物質がさらに好ましい。   The alloy-based active material occludes lithium by being alloyed with lithium at the time of charging under a negative electrode potential, and releases lithium at the time of discharging. The alloy-based active material is not particularly limited, and known materials can be used, but a silicon-based active material and a tin-based active material are preferable, and a silicon-based active material is more preferable.

珪素系活物質には、珪素、珪素化合物、これらの部分置換体及び固溶体等がある。珪素化合物には、珪素酸化物、珪素炭化物、珪素窒化物、珪素合金等があり、これらの中でも、珪素酸化物が好ましい。   Examples of silicon-based active materials include silicon, silicon compounds, partial substitutes, and solid solutions thereof. Examples of the silicon compound include silicon oxide, silicon carbide, silicon nitride, and silicon alloy, and among these, silicon oxide is preferable.

珪素酸化物には、ＳｉＯａ（０．０５＜ａ＜１．９５）で表される酸化珪素等がある。珪素炭化物には、ＳｉＣｂ（０＜ｂ＜１）で表される炭化珪素等がある。珪素窒化物には、ＳｉＮｃ（０＜ｃ＜４／３）で表される窒化珪素等がある。 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).

珪素合金は、珪素と異種元素Ａとの合金である。異種元素Ａとしては、Ｆｅ、Ｃｏ、Ｓｂ、Ｂｉ、Ｐｂ、Ｎｉ、Ｃｕ、Ｚｎ、Ｇｅ、Ｉｎ、Ｓｎ及びＴｉよりなる群から選ばれる少なくとも１つの元素を使用できる。部分置換体は、珪素又は珪素化合物に含まれる珪素
の一部を異種元素Ｂで置換した化合物である。異種元素Ｂとしては、Ｂ、Ｍｇ、Ｎｉ、Ｔｉ、Ｍｏ、Ｃｏ、Ｃａ、Ｃｒ、Ｃｕ、Ｆｅ、Ｍｎ、Ｎｂ、Ｔａ、Ｖ、Ｗ、Ｚｎ、Ｃ、Ｎ及びＳｎよりなる群から選ばれる少なくとも１つの元素を使用できる。 The silicon alloy is an alloy of silicon and a different element A. As 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 different 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.

錫系活物質には、錫、錫酸化物、錫窒化物、錫合金、錫化合物及びこれらの固溶体等があり、錫酸化物が好ましい。錫酸化物には、ＳｎＯｄ（０＜ｄ＜２）、ＳｎＯ２等の酸化錫がある。錫合金には、Ｎｉ−Ｓｎ合金、Ｍｇ−Ｓｎ合金、Ｆｅ−Ｓｎ合金、Ｃｕ−Ｓｎ合金、Ｔｉ−Ｓｎ合金等がある。錫化合物には、ＳｎＳｉＯ３、Ｎｉ２Ｓｎ４、Ｍｇ２Ｓｎ等がある。 Examples of the tin-based active material include tin, tin oxide, tin nitride, tin alloy, tin compound, and a solid solution thereof, and tin oxide is preferable. Examples of the tin oxide include tin oxides such as SnO d (0 <d <2) and SnO 2 . Examples of the tin alloy include a Ni—Sn alloy, a Mg—Sn alloy, a Fe—Sn alloy, a Cu—Sn alloy, and a Ti—Sn alloy. Examples of the tin compound include SnSiO 3 , Ni 2 Sn 4 , and Mg 2 Sn.

合金系活物質は、１種を単独で又は２種以上を組み合わせて使用できる。   An alloy type active material can be used individually by 1 type or in combination of 2 or more types.

薄膜状負極活物質層１１は、気相法により、負極集電体１０の表面に薄膜状に形成される。気相法には、真空蒸着法、スパッタ法、イオンプレーティング法、レーザーアブレーション法、化学気相成長（ＣＶＤ；Chemical Vapor Deposition）法、プラズマ化学気相成長法、溶射法等がある。これらの中でも、真空蒸着法が好ましい。   The thin film negative electrode active material layer 11 is formed in a thin film shape on the surface of the negative electrode current collector 10 by a vapor phase method. Examples of 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. Among these, the vacuum evaporation method is preferable.

例えば、電子ビーム式真空蒸着装置において、シリコンターゲットの鉛直方向上方に負極集電体１０を配置する。シリコンターゲットに電子ビームを照射してシリコン蒸気を発生させ、このシリコン蒸気を負極集電体１０の表面に析出させる。これにより、珪素からなる薄膜状負極活物質層１１が負極集電体１０の表面に形成される。このとき、電子ビーム式真空蒸着装置内に酸素又は窒素を供給すると、珪素酸化物又は珪素窒化物を含有する薄膜状負極活物質層１１が形成される。   For example, in the electron beam vacuum deposition apparatus, the negative electrode current collector 10 is disposed above the silicon target in the vertical direction. The silicon target is irradiated with an electron beam to generate silicon vapor, 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, the thin film negative electrode active material layer 11 containing silicon oxide or silicon nitride is formed.

本実施形態では、薄膜状負極活物質層１１は、薄膜状のベタ膜として形成されるが、それに限定されず、気相法により、格子等のパターン形状や複数の柱状体の集合体として形成してもよい。複数の柱状体は、それぞれが合金系活物質を含有し、負極集電体表面から外方に延びかつ互いに離隔するように形成される。   In the present embodiment, the thin-film negative electrode active material layer 11 is formed as a thin-film solid film, but is not limited thereto, and is formed as a pattern shape such as a lattice or an assembly of a plurality of columnar bodies by a vapor phase method. May be. Each of the plurality of columnar bodies contains an alloy-based active material, and is formed to extend outward from the surface of the negative electrode current collector and to be separated from each other.

この場合、負極集電体の表面に複数の凸部を規則的に又は不規則に形成し、１つの凸部の表面に１つの柱状体を形成するのが好ましい。凸部の鉛直方向上方からの正投影図における形状には、菱形、円形、楕円形、多角形（三角形、八角形等）などがある。凸部を規則的に形成する場合、凸部の負極集電体表面での配置には、碁盤目状配置、格子状配置、千鳥格子状配置、最密充填配置等がある。また、凸部は、負極集電体の厚さ方向の一方の表面又は両方の表面に形成される。また、柱状体の高さは好ましくは３μｍ〜３０μｍである。   In this case, it is preferable to form a plurality of convex portions regularly or irregularly on the surface of the negative electrode current collector and to form one columnar body on the surface of one convex portion. Examples of the shape in the orthographic projection from above in the vertical direction of the convex portion include a rhombus, a circle, an ellipse, and a polygon (triangle, octagon, etc.). When the convex portions are regularly formed, the arrangement of the convex portions on the surface of the negative electrode current collector 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. The height of the columnar body is preferably 3 μm to 30 μm.

負極リード１３は、ニッケル、ニッケル合金、銅及び銅合金よりなる群から選ばれる少なくとも１つの金属又は合金を含有する。ニッケル合金には、ニッケル−珪素合金、ニッケル−錫合金、ニッケル−コバルト合金、ニッケル−鉄合金、ニッケル−マンガン合金等がある。銅合金には、銅−ニッケル合金 、銅−鉄合金、銅−銀合金、銅−りん合金、銅−アルミニウム合金、銅−珪素合金、銅−錫合金、銅−ジルコニア合金、銅−ベリリウム合金等がある。   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. Examples of the 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.

これらの中でも、負極集電体１０と負極リード１３との接合強度を高める観点から、ニッケル、銅、銅−ニッケル合金が好ましく、銅がさらに好ましい。また、銅とニッケルとのクラッド材を用いてもよい。負極リード１３は、前述した金属又は合金を一般的なリードの形態に成形することにより製造される。   Among these, from the viewpoint of increasing the bonding strength between the negative electrode current collector 10 and the negative electrode lead 13, nickel, copper, and a copper-nickel alloy are preferable, and copper is more preferable. Further, 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.

溶融部１７は負極集電体１０と負極リード１３との間に介在し、負極集電体１０と負極
リード１３とを導通させるとともに、負極集電体１０と負極リード１３を接合する。溶融部１７は負極リード１３の幅より広く、負極リード１３が対向しない負極板１の端面の少なくとも一部にも溶融部１７が設けられている。負極リード１３が対向しない溶融部１７を溶融部Ｗとして、その大きさはリードの端面から溶融端部までの図１（ａ）の矢印で示される寸法と定義する。負極板１の溶融幅Ｗは０．１ｍｍ以上、１０ｍｍ以下である。本実施形態では、負極集電体１０と負極リード１３とが対向する全領域を連続的に溶融しているが、負極リード１３の両端部と負極板１の少なくとも一部が溶融していれば良く、間欠的に溶融部１７を形成しても良い。 The melting part 17 is interposed between the negative electrode current collector 10 and the negative electrode lead 13, makes the negative electrode current collector 10 and the negative electrode lead 13 conductive, and joins the negative electrode current collector 10 and the negative electrode lead 13. The melting part 17 is wider than the negative electrode lead 13, and the melting part 17 is also provided on at least a part of the end face of the negative electrode plate 1 where the negative electrode lead 13 does not face. The melted portion 17 that does not face the negative electrode lead 13 is defined as a melted portion W, and the size thereof is defined as a dimension indicated by an arrow in FIG. 1A from the end surface of the lead to the melted end portion. The melt width W of the negative electrode plate 1 is 0.1 mm or more and 10 mm or less. In this embodiment, the entire region where the negative electrode current collector 10 and the negative electrode lead 13 face each other is continuously melted. However, if both ends of the negative electrode lead 13 and at least a part of the negative electrode plate 1 are melted. For example, the melted portion 17 may be formed intermittently.

溶融部１７は、後記する方法でアーク溶接を行うことにより形成されるものと推測される。後記する方法でアーク溶接を行うと、溶接を施す部位において、負極リード１３、負極集電体１０及び薄膜状負極活物質層１１のそれぞれ少なくとも一部が溶融する。その溶融部分のほぼ全域において、負極リード１３、負極集電体１０及び薄膜状負極活物質層１１に含まれる元素が均一に分散する合金化が起こるものと推測される。これにより負極リード１３幅全域が、負極集電体１０と強固に接続される。   It is estimated that the melting part 17 is formed by performing arc welding by a method described later. When arc welding is performed by a method to be described later, at least a part of each of the negative electrode lead 13, the negative electrode current collector 10, and the thin film negative electrode active material layer 11 is melted at a portion to be welded. It is presumed that alloying in which the elements contained in the negative electrode lead 13, the negative electrode current collector 10, and the thin film negative electrode active material layer 11 are uniformly dispersed occurs in almost the entire molten portion. As a result, the entire width of the negative electrode lead 13 is firmly connected to the negative electrode current collector 10.

負極リード１３が対向していない負極板１にアークを照射すると、負極集電体１０と薄膜状負極活物質層１１のみが溶融して負極集電体１０及び薄膜状負極活物質層１１に含まれる元素が均一に分散する合金化が起こるものと推測される。この溶融部１７の合金層は負極板１よりも強度が高い。負極板１のみが溶融して形成した溶融部１７と負極リード１３と負極板１とが対向している領域で溶融して形成した溶融部１７とは連結している。これより、負極リード１３のねじれや変角して接合部端部に応力がかかっても、接合周囲の負極板１に亀裂や破断が生じることがない。すなわち、応力が集中する領域全てに、強度が高い溶融部を形成することで、接続信頼性を高めている。   When the negative electrode plate 1 not facing the negative electrode lead 13 is irradiated with an arc, only the negative electrode current collector 10 and the thin film negative electrode active material layer 11 are melted and included in the negative electrode current collector 10 and the thin film negative electrode active material layer 11. It is presumed that alloying occurs in which uniformly dispersed elements occur. The alloy layer of the melting part 17 has higher strength than the negative electrode plate 1. The melted portion 17 formed by melting only the negative electrode plate 1 is connected to the melted portion 17 formed by melting in a region where the negative electrode lead 13 and the negative electrode plate 1 face each other. As a result, even if the negative electrode lead 13 is twisted or bent and stress is applied to the end portion of the joint, the negative electrode plate 1 around the joint does not crack or break. That is, the connection reliability is improved by forming a melted portion having a high strength in all regions where stress is concentrated.

また、溶融部１７には、少なくとも、負極集電体１０と薄膜状負極活物質層１１と負極リード１３に含まれる金属元素の少なくとも１つが均一に分散している。したがって、溶融部１７は良好な導電性を有し、負極集電体１０と負極リード１３とを導通させることができる。これにより、負極板１は、負極集電体１０と負極リード１３との高強度での接合性及び良好な集電性能を併せ持つことができる。   Further, at least one of the metal elements contained in at least the negative electrode current collector 10, the thin film negative electrode active material layer 11, and the negative electrode lead 13 is uniformly dispersed in the melted portion 17. Therefore, the melting part 17 has good electrical conductivity, and can make the negative electrode current collector 10 and the negative electrode lead 13 conductive. Thereby, the negative electrode plate 1 can have both high-strength bondability and good current collecting performance between the negative electrode current collector 10 and the negative electrode lead 13.

溶融部１７は、たとえば、薄膜状負極活物質層１１中の合金系負極活物質に含有される半金属元素と負極集電体１０または負極リード１３に含有される金属元素との合金を含んでいる。合金系負極活物質に含有される半金属元素としては、たとえば、珪素、錫などが挙げられる。負極集電体１０及び負極リード１３に含有される主な金属元素としては、銅、ニッケルなどが挙げられる。これらの中でも、合金系負極活物質に含有される半金属元素を均一に分散させることなどを考慮すると、銅が好ましい。   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. Yes. Examples of the metalloid element contained in the alloy-based negative electrode active material include silicon and tin. Examples of 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 preferable in consideration of uniformly dispersing the metalloid element contained in the alloy-based negative electrode active material.

負極板１と負極リード１３との接合強度は、次のような測定法により引張強度として測定できる。図５（ａ）及び図５（ｂ）は、負極リード１３の負極集電体１０に対する引張強度を測定するための試料の作製方法を示す斜視図である。図６は、負極リード１３の負極集電体１０に対する引張強度の測定方法を示す斜視図である。   The bonding strength between the negative electrode plate 1 and the negative electrode lead 13 can be measured as the tensile strength by the following measurement method. FIG. 5A and FIG. 5B are perspective views showing a method for preparing a sample 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 showing a method for measuring the tensile strength of the negative electrode lead 13 with respect to the negative electrode current collector 10.

図５（ａ）に示すように、まず、負極リード１３の長さが、負極板１の幅と同じになるように、負極リード１３を切断する。次に、負極板１の長さが、負極リード１３が接合されている端部から引っ張り強度測定治具に設置しやすいように適切な長さに負極板１を切断する。負極リード１３と負極板１が対向している領域の接合幅をｄとする。図５（ａ）では、溶融領域が連続的に形成されているため、接合幅は負極リード１３の幅に等しい。引き続き、図５（ｂ）に示すように、負極リード１３を負極板１から剥がすように、矢印６６の方向に折り返し、引張強度測定用の試料６５を準備する。   As shown in FIG. 5A, first, 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. Next, the negative electrode plate 1 is cut to an appropriate length so that the length of the negative electrode plate 1 can be easily installed in the tensile strength measuring jig from the end where the negative electrode lead 13 is joined. Let d be the bonding width of the region where the negative electrode lead 13 and the negative electrode plate 1 face each other. In FIG. 5A, since the melted region is continuously formed, the bonding width is equal to the width of the negative electrode lead 13. Subsequently, as shown in FIG. 5B, the negative electrode lead 13 is folded in the direction of the arrow 66 so as to peel off the negative electrode plate 1 to prepare a sample 65 for measuring the tensile strength.

このようにして得られた試料６５を用い、図６に示す測定方法により、引張強度を測定する。万能試験機７０の下部固定治具７１に、負極板１の溶融部１７が形成されていない側の端部を挟んで固定し、上部固定治具７２に負極リード１３の溶融部１７が形成されていない側の端部（折り返し側の端部）を挟んで固定する。   Using the sample 65 thus obtained, the tensile strength is measured by the measuring method shown in FIG. The end of the negative electrode plate 1 on the side where the melting part 17 is not formed is fixed to the lower fixing jig 71 of the universal testing machine 70, and the melting part 17 of the negative electrode lead 13 is formed on the upper fixing jig 72. Fix it with the end on the non-turned side (the end on the folded side).

室温２５℃にて、上部固定治具７２を５ｍｍ／分の速度で矢印７３の方向に移動させて負極リード１３を引っ張り、負極板１と負極リード１３との接合部分（溶融部１７）が破断するときの引張強度（Ｎ）を測定する。得られた引張強度の測定値と接合幅ｄの測定値とから、接合幅１ｍｍ当たりの引張強度（Ｎ／ｍｍ）を求められる。本実施形態の負極板１と負極リード１３との溶接強度は０．５Ｎ／ｍｍから５０Ｎ／ｍｍとなるように溶接条件を設定することが望ましい。   At a room temperature of 25 ° C., the upper fixing jig 72 is moved at a speed of 5 mm / min in the direction of the arrow 73 to pull the negative electrode lead 13, and the joint portion (melting portion 17) between the negative electrode plate 1 and the negative electrode lead 13 is broken. Measure the tensile strength (N). The tensile strength (N / mm) per 1 mm of bonding width can be obtained from the measured value of tensile strength and the measured value of bonding width d. It is desirable to set the welding conditions so that the welding strength between the negative electrode plate 1 and the negative electrode lead 13 of the present embodiment is 0.5 N / mm to 50 N / mm.

図２は、本実施形態であるリチウムイオン電池用負極の製造方法を説明する縦断面図である。本実施形態のリチウムイオン電池用負極の製造方法（以下「本実施形態の製造方法」とする）は、第１工程と、第２工程と、第３工程と、を備える。以下に、各工程について詳しく説明する。   FIG. 2 is a longitudinal sectional view for explaining a method for producing a negative electrode for a lithium ion battery according to this embodiment. The method for producing a negative electrode for a lithium ion battery of the present embodiment (hereinafter referred to as “production method of the present embodiment”) includes a first step, a second step, and a third step. Below, each process is demonstrated in detail.

第１工程では、負極板１及び負極リード１３を準備する。   In the first step, the negative electrode plate 1 and the negative electrode lead 13 are prepared.

負極板１は、負極集電体１０と、負極集電体１０の厚さ方向の両面に形成された薄膜状負極活物質層１１と、を備える。本実施形態では、薄膜状負極活物質層１１は、負極集電体１０の厚さ方向の両面に形成されているが、片面に形成されていてもよい。   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 of the negative electrode current collector 10 in the thickness direction. In the present embodiment, the thin film negative electrode active material layer 11 is formed on both surfaces of the negative electrode current collector 10 in the thickness direction, but may be formed on one surface.

第２工程では、第１板２０と第２板２１とからなる一組の溶接治具１４を用い、第１板２０と第２板２１との間に、負極板１と負極リード１３とを挟持する。溶接治具１４は、銅等の金属材料を所定の形状に成形することにより、作製される。溶接治具１４による負極板１及び負極リード１３の挟持は、薄膜状負極活物質層１１の表面と負極リード１３の表面とが重なり、且つ、負極板端面１ａと負極リード端面１３ａとからなる平坦な溶接端面１６を含む溶接領域が露出するように、実施される。   In the second step, the negative electrode plate 1 and the negative electrode lead 13 are connected between the first plate 20 and the second plate 21 by using a set of welding jigs 14 including the first plate 20 and the second plate 21. Hold it. 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 by the welding jig 14 so that the surface of the thin-film negative electrode active material layer 11 and the surface of the negative electrode lead 13 overlap, and the flat surface is composed of the negative electrode plate end surface 1a and the negative electrode lead end surface 13a. This is performed so that the welding region including the weld end surface 16 is exposed.

ここで、薄膜状負極活物質層１１の表面とは、薄膜状負極活物質層１１の厚さ方向の一方の表面である。負極リード１３の表面とは、負極リード１３の厚さ方向の一方の表面である。薄膜状負極活物質層１１の表面の全面と、負極リード１３の表面の全面とが重なっている必要はなく、それぞれの表面の少なくとも一部が重なって、接触していればよい。   Here, the surface of the thin film negative electrode active material layer 11 is one surface of the thin film negative electrode active material layer 11 in the thickness direction. The surface of the negative electrode lead 13 is one surface of the negative electrode lead 13 in the thickness direction. 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.

本実施形態では、負極板端面１ａは、負極板１の長手方向の一方の端面であり、負極リード端面１３ａは、負極リード１３の幅方向の一方の端面であるが、それに限定されない。負極板端面１ａは、負極板１の長手方向の一端面又は負極板１の幅方向の一端面のいずれでもよい。負極リード端面１３ａは、負極リード１３の長手方向の一端面又は負極リード１３の幅方向の一端面のいずれでもよい。   In the present embodiment, the negative electrode plate end surface 1 a is one end surface in the longitudinal direction of the negative electrode plate 1, and the negative electrode lead end surface 13 a is one end surface in the width direction of the negative electrode lead 13, but is not limited thereto. The negative electrode plate end surface 1 a may be either one end surface in the longitudinal direction of the negative electrode plate 1 or one end surface in the width direction of the negative electrode plate 1. The negative electrode lead end surface 13 a may be either one end surface in the longitudinal direction of the negative electrode lead 13 or one end surface in the width direction of the negative electrode lead 13.

負極板端面１ａ及び負極リード端面１３ａについて、長手方向又は幅方向のいずれにするかは、電極群の形態（捲回型、扁平型、積層型等）、リチウムイオン電池の形態（角型、円筒型、扁平型、ラミネートフィルムパック型、コイン型等）及び設計（寸法、容量、用途等）等の条件に応じて適宜選択される。   The negative electrode plate end surface 1a and the negative electrode lead end surface 13a are either in the longitudinal direction or in the width direction depending on the form of electrode group (winding type, flat type, laminated type, etc.), or the form of lithium ion battery (square type, cylindrical type). Mold, flat type, laminated film pack type, coin type, etc.) and design (size, capacity, usage, etc.) and the like.

また、溶接治具１４により負極板１と負極リード１３とを挟持する際にしては、負極板端面１ａと負極リード端面１３ａとが連続した同一平面になり、平坦な溶接端面１６が形成されるように、負極板１及び負極リード１３が配置される。溶接端面１６を含む溶接領
域とは、後述する条件で溶接端面１６に対して垂直な方向１９からアーク放電を行った場合に、負極板１及び負極リード１３におけるアーク放電のエネルギーが及ぶ領域である。 Further, when the negative electrode plate 1 and the negative electrode lead 13 are sandwiched by the welding jig 14, the negative electrode plate end surface 1a and the negative electrode lead end surface 13a are in the same continuous plane, and a flat weld end surface 16 is formed. Thus, the negative electrode plate 1 and the negative electrode lead 13 are disposed. The welding region including the weld end surface 16 is a region where the arc discharge energy reaches the negative electrode plate 1 and the negative electrode lead 13 when arc discharge is performed from a direction 19 perpendicular to the weld end surface 16 under the conditions described later. .

本実施形態の溶接治具１４は、第１板２０と第２板２１との間に負極板１と負極リード１３とを挟持した状態で、第１板２０の第１凹部２０ｘと第２板２１の第２凹部２１ｘとにより形成される窪みを有している。   The welding jig 14 of the present embodiment includes the first recess 20x and the second plate of the first plate 20 with the negative electrode plate 1 and the negative electrode lead 13 sandwiched between the first plate 20 and the second plate 21. And a second recess 21x.

第３工程では、溶接端面１６を含む溶接領域に向けてアーク放電することにより、溶接領域を溶融させ、負極集電体１０と負極リード１３とをアーク溶接する。   In the third step, arc discharge is performed toward the welding region including the weld end face 16 to melt the welding region, and the negative electrode current collector 10 and the negative electrode lead 13 are arc-welded.

具体的には、負極板端面１ａと負極リード端面１３ａとからなる平坦な溶接端面１６に対して、垂直な方向に、図示しないアーク溶接用電極を配置する。そして、アーク溶接用電極の溶接トーチから矢印１９の方向にエネルギーを照射する。溶接トーチから照射されるエネルギーは、溶接端面１６に照射される。これにより、溶接端面１６を含む溶接領域が均一に溶融して、その後固化して溶融部１７が形成される。溶接トーチは矢印１８の方向で、負極リード１３の幅よりも広く移動させ、アーク溶接を行う。負極リード１３が対向しない負極板１の端面にも溶融部を形成する。   Specifically, an arc welding electrode (not shown) is arranged in a direction perpendicular to the flat welding end surface 16 composed of the negative electrode plate end surface 1a and the negative electrode lead end surface 13a. Then, energy is irradiated in the direction of arrow 19 from the welding torch of the electrode for arc welding. The energy irradiated from the welding torch is irradiated to the welding end surface 16. As a result, the weld region including the weld end face 16 is uniformly melted and then solidified to form the melted portion 17. The welding torch is moved wider than the width of the negative electrode lead 13 in the direction of the arrow 18 to perform arc welding. A melted part is also formed on the end face of the negative electrode plate 1 where the negative electrode lead 13 is not opposed.

ここで、負極リード１３が対向しない負極板１の溶融幅Ｗは０．１ｍｍ以上、１０ｍｍ以下であることが望ましい。溶融幅Ｗが０．１ｍｍ以下では、負極リード１３の端部溶融と負極板１の端面の溶融部が十分に形成されず、強度が不足する。また、負極リードの端部に生成されやすいバリが溶融せず、鋭利な部分が残存する可能性がある。溶融幅Ｗが１０ｍｍ以上では、正極と対向して電極群を形成する領域にロスが生じ、高容量の電池を設計することが出来ない。溶接幅Ｗを制御する方法としては、溶接トーチの移動幅を変える、アークのエネルギーを変える、溶接トーチと負極板１の端面との距離を変える方法などがある。   Here, it is desirable that the melt width W of the negative electrode plate 1 to which the negative electrode lead 13 does not face is 0.1 mm or more and 10 mm or less. When the melting width W is 0.1 mm or less, the end portion melting of the negative electrode lead 13 and the melting portion of the end surface of the negative electrode plate 1 are not sufficiently formed, and the strength is insufficient. In addition, burrs that are likely to be generated at the end of the negative electrode lead are not melted, and a sharp portion may remain. When the melting width W is 10 mm or more, a loss occurs in a region where the electrode group is formed facing the positive electrode, and a high-capacity battery cannot be designed. As a method of controlling the welding width W, there are a method of changing the moving width of the welding torch, changing the energy of the arc, and changing the distance between the welding torch and the end face of the negative electrode plate 1.

アーク溶接用電極を負極板１の幅方向に移動させながら、間欠的にアーク溶接を行ってもよい。これにより、負極板１の幅方向に間欠的に溶融部１７が形成される。アーク溶接を実施すると、負極集電体１０と負極リード１３との任意の箇所に、溶融部１７を容易に形成できる。   Arc welding may be performed intermittently while moving the electrode for arc welding in the width direction of the negative electrode plate 1. Thereby, the melting part 17 is intermittently formed in the width direction of the negative electrode plate 1. When arc welding is performed, the melted portion 17 can be easily formed at any location between the negative electrode current collector 10 and the negative electrode lead 13.

アーク溶接法の中でも、プラズマ溶接法及びＴＩＧ（Tungsten Inert Gas）溶接法が好ましい。溶融部１７内での元素の均一分散性等を考慮すると、プラズマ溶接法が特に好ましい。溶融部１７内で元素が均一に分散するほど、溶融部１７による負極集電体１０と負極リード１３との接合性及び導通性が向上するものと推測される。プラズマ溶接及びＴＩＧ溶接は、それぞれ、市販されているプラズマ溶接機及びＴＩＧ溶接機を用いて実施される。   Among arc welding methods, a plasma welding method and a TIG (Tungsten Inert Gas) welding method are preferable. In view of the uniform dispersibility of the elements in the melting part 17, the plasma welding method is particularly preferable. It is presumed that the more uniformly the elements are dispersed in the melted part 17, the better the bondability and conductivity between the negative electrode current collector 10 and the negative electrode lead 13 by the melted part 17. Plasma welding and TIG welding are performed using a commercially available plasma welding machine and TIG welding machine, respectively.

プラズマ溶接は、例えば、溶接電流値、溶接速度（溶接トーチの移動速度）、溶接時間、プラズマガス及びシールドガスの種類とその流量等の条件を適宜選択して実施できる。これらの条件を選択することにより、生成する溶融部１７による負極集電体１０と負極リード１３との接合性及び導通性を制御できる。   For example, plasma welding can be performed by appropriately selecting conditions such as a welding current value, a welding speed (moving speed of the welding torch), a welding time, types of plasma gas and shield gas, and flow rates thereof. By selecting these conditions, it is possible to control the bondability and conductivity between the negative electrode current collector 10 and the negative electrode lead 13 by the melting portion 17 to be generated.

溶接電流値は、例えば、１Ａ〜１００Ａである。溶接トーチの掃引速度は、例えば、１ｍｍ／秒〜１００ｍｍ／秒である。プラズマガスにはアルゴンガス等を使用できる。プラズマガス流量は、例えば、１０ｍｌ／分〜１０リットル／分である。シールドガスには、アルゴン、水素等を使用できる。シールドガス流量は、例えば、１０ｍｌ／分〜１０リットル／分である。   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 can be used as the plasma gas. The plasma gas flow rate is, for example, 10 ml / min to 10 liter / min. Argon, hydrogen, etc. can be used for the shielding gas. The shield gas flow rate is, for example, 10 ml / min to 10 liter / min.

なお、アーク溶接の溶接条件によっては、溶融部１７の内部に、薄膜状負極活物質層１１の一部が溶融せずにそのまま残存することがある。しかし、アーク溶接で溶融部１８を形成する限り、溶融部１７内部に残存する薄膜状負極活物質層１１が、溶融部１７による負極集電体１０と負極リード１３との接合性及び導通性を実用範囲よりも低下させることはない。   Depending on the welding conditions of arc welding, a part of the thin film negative electrode active material layer 11 may remain in the melted portion 17 without melting. However, as long as the melted part 18 is formed by arc welding, the thin-film negative electrode active material layer 11 remaining in the melted part 17 has a bonding property and conductivity between the negative electrode current collector 10 and the negative electrode lead 13 by the melted part 17. There is no reduction beyond the practical range.

一方、アーク溶接に代えて抵抗溶接を実施した場合には、薄膜状負極活物質層１１が合金系活物質を含有することにより、薄膜状負極活物質層１１に電流が流れない。したがって、負極集電体１０と薄膜状負極活物質層１１との界面において、負極集電体１０の一部が局所的に溶融することがある。また、薄膜状負極活物質層１１と負極リード１３との接触箇所において、負極リード１３の一部が局所的に溶融することがある。しかしながら、負極集電体１０から薄膜状負極活物質層１１を介して負極リード１３に至る領域が溶融することはない。超音波溶接を実施しても、抵抗溶接を実施した場合と同様である。   On the other hand, when resistance welding is performed instead of arc welding, the thin-film negative electrode active material layer 11 contains an alloy-based active material, so that no current flows through the thin-film negative electrode active material layer 11. Therefore, a part of the negative electrode current collector 10 may locally melt at the interface between the negative electrode current collector 10 and the thin film negative electrode active material layer 11. Further, a part of the negative electrode lead 13 may be locally melted at a contact portion between the thin film negative electrode active material layer 11 and the negative electrode lead 13. However, the region from the negative electrode current collector 10 to the negative electrode lead 13 through the thin film negative electrode active material layer 11 does not melt. Even if ultrasonic welding is performed, it is the same as when resistance welding is performed.

すなわち、抵抗溶接及び超音波抵抗では、負極集電体１０及び／又は負極リード１３が局所的に溶融するのみであり、薄膜状負極活物質層１１は溶融しない。したがって、負極集電体１０と負極リード１３とを接合することはできない。外観上は接合しているように見えても、電池の組立て時等にほぼ確実に断線が生じる。   That is, in resistance welding and ultrasonic resistance, the negative electrode current collector 10 and / or the negative electrode lead 13 are only locally melted, and the thin film negative electrode active material layer 11 is not melted. Therefore, the negative electrode current collector 10 and the negative electrode lead 13 cannot be joined. Even if it appears to be joined in appearance, disconnection occurs almost certainly when the battery is assembled.

本実施形態の製造方法では、薄膜状負極活物質層１１が珪素系活物質を含有する場合、第１工程と第２工程との間に、薄膜状負極活物質層１１にリチウムを吸蔵させる工程（以下「リチウム吸蔵工程」とする）を設けるのが好ましい。これにより、第３工程で得られる溶融部１８内部における合金の均一分散性がより一層向上する。   In the manufacturing method of the present embodiment, when the thin film negative electrode active material layer 11 contains a silicon-based active material, the thin film negative electrode active material layer 11 occludes lithium between the first step and the second step. (Hereinafter referred to as “lithium storage step”) is preferably provided. Thereby, the uniform dispersibility of the alloy in the fusion | melting part 18 obtained at a 3rd process further improves.

また、リチウム吸蔵工程を設けると、リチウム吸蔵工程を設けない場合に比べて、溶融部１７の形状の均一性を損なうことなく、接合強度を確保することができる。これにより、幅方向全域で溶融部１７の負極集電体１０及び負極リード１３との接触面積が大きくなる。その結果、溶融部１７による負極集電体１０と負極リード１３との接合性及び導通性がより一層向上する。   In addition, when the lithium occlusion process is provided, the bonding strength can be ensured without impairing the uniformity of the shape of the melted portion 17 as compared with the case where the lithium occlusion process is not provided. Thereby, the contact area between the negative electrode current collector 10 and the negative electrode lead 13 of the melting portion 17 increases in the entire width direction. As a result, the bondability and conductivity between the negative electrode current collector 10 and the negative electrode lead 13 by the melting part 17 are further improved.

薄膜状負極活物質層１１へのリチウムの吸蔵は、例えば、真空蒸着法、電気化学的な方法、薄膜状負極活物質層１１表面へのリチウム箔の貼着等により実施される。例えば、真空蒸着法によれば、真空蒸着装置のターゲットに金属リチウムを装着し、真空蒸着を行うと、薄膜状負極活物質層１１にリチウムが吸蔵される。リチウムの吸蔵量は特に制限されないが、薄膜状負極活物質層１１の不可逆容量分のリチウムを吸蔵させるのが好ましい。   The insertion of lithium into the thin film negative electrode active material layer 11 is performed by, for example, a vacuum deposition method, an electrochemical method, sticking of a lithium foil to the surface of the thin film negative electrode active material layer 11, or the like. For example, according to the vacuum deposition method, when metal lithium is attached to the target of the vacuum deposition apparatus and vacuum deposition is performed, lithium is occluded in the thin film negative electrode active material layer 11. Although the occlusion amount of lithium is not particularly limited, it is preferable to occlude lithium for the irreversible capacity of the thin film negative electrode active material layer 11.

図３は、本発明の第２実施形態であるリチウムイオン電池２５の構成を模式的に示す縦断面図である。リチウムイオン電池２５は、本発明の第１実施形態の製造方法により得られた負極２８を含む以外は、従来のリチウムイオン電池と同様の構成を有している。   FIG. 3 is a longitudinal sectional view schematically showing a configuration of the lithium ion battery 25 according to the second embodiment of the present invention. The lithium ion battery 25 has the same configuration as the conventional lithium ion battery except that it includes the negative electrode 28 obtained by the manufacturing method of the first embodiment of the present invention.

本実施形態のリチウムイオン電池２５は、負極２８を含むことにより、高容量及び高出力を有し、出力特性、サイクル特性等の電池性能に優れている。また、負極２８において負極板１（負極集電体１０）と負極リード１３とが強固にかつ導通性良く接合されている。
負極板１と負極リード１３とが接合されている溶融部１７の幅が負極リード１３の幅より広く、負極リード１３が対向していない負極板１の端部が溶融していることで、負極リード１３は高い接合強度を有する。これにより、負極２８の集電性能、電池の出力特性等が長期にわたって高水準で維持される。したがって、本実施形態のリチウムイオン電池２５は耐用寿命が長い。 By including the negative electrode 28, the lithium ion battery 25 of this embodiment has high capacity and high output, and is excellent in battery performance such as output characteristics and cycle characteristics. Further, in the negative electrode 28, the negative electrode plate 1 (negative electrode current collector 10) and the negative electrode lead 13 are joined firmly and with good conductivity.
The width of the melted portion 17 where the negative electrode plate 1 and the negative electrode lead 13 are joined is wider than the width of the negative electrode lead 13, and the end of the negative electrode plate 1 where the negative electrode lead 13 is not opposed is melted. The lead 13 has a high bonding strength. Thereby, 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.

リチウムイオン電池２５は、捲回型電極群２６と、捲回型電極群２６の長手方向の両端にそれぞれ装着される上部絶縁板３０及び下部絶縁板３１と、捲回型電極群２６等を収容する電池ケース３２と、封口板３４により支持される正極端子３３と、電池ケース３２を封口する封口板３４と、非水電解質（図示しない）とを含む。   The lithium ion battery 25 accommodates a wound electrode group 26, an upper insulating plate 30 and a lower insulating plate 31, which are respectively attached to both ends in the longitudinal direction of the wound electrode group 26, and the wound electrode group 26. A battery case 32, a positive electrode terminal 33 supported by the sealing plate 34, a sealing plate 34 for sealing the battery case 32, and a nonaqueous electrolyte (not shown).

捲回型電極群２６の長手方向の両端部に上部絶縁板３０及び下部絶縁板３１を装着し、これを電池ケース３２に収容する。このとき、正極２７の正極リード３６及び負極２８の負極リード１３が、それぞれ所定の箇所に接続される。電池ケース３２内に非水電解質を注液する。次に、電池ケース３２の開口部分に、正極端子３３を支持する封口板３４を装着し、電池ケース３２の開口端部を封口板３４に向けてかしめ付ける。これにより、電池ケース３２が封口され、リチウムイオン電池２５が得られる。   The upper insulating plate 30 and the lower insulating plate 31 are attached to both ends in the longitudinal direction of the wound electrode group 26 and accommodated in the battery case 32. At this time, 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 nonaqueous electrolyte is injected into the battery case 32. Next, a sealing plate 34 that supports the positive terminal 33 is attached to the opening of the battery case 32, and the opening end of the battery case 32 is caulked toward the sealing plate 34. Thereby, the battery case 32 is sealed and the lithium ion battery 25 is obtained.

捲回型電極群２６は、帯状の正極２７と、帯状の負極２８と、帯状のセパレータ２９と、備える。捲回型電極群２６は、例えば、正極２７と負極２８との間にセパレータ２９を介在させた積層物を、その長手方向の一端部を捲回軸にして捲回することにより得られる。本実施形態では、捲回型電極群２６を使用するが、それに限定されず、正極２７と負極２８との間にセパレータ２９を介在させて積層した積層型電極群を使用してもよい。   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 portion in the longitudinal direction as a winding axis. In this embodiment, the wound electrode group 26 is used. However, the present invention is not limited to this, and a stacked electrode group in which a separator 29 is interposed between the positive electrode 27 and the negative electrode 28 may be used.

正極２７は、正極板３５と、正極リード３６と、を備える。正極板３５は、正極集電体と、正極活物質層と、を備える。   The positive electrode 27 includes a positive electrode plate 35 and a positive electrode lead 36. The positive electrode plate 35 includes a positive electrode current collector and a positive electrode active material layer.

正極集電体には、ステンレス鋼、チタン、アルミニウム、アルミニウム合金等の金属材料からなる、多孔性又は無孔の導電性基板を使用できる。   As the positive electrode current collector, a porous or non-porous conductive substrate made of a metal material such as stainless steel, titanium, aluminum, or an aluminum alloy can be used.

多孔性導電性基板には、メッシュ体、ネット体、パンチングシート、ラス体、多孔質体、発泡体、不織布等がある。無孔の導電性基板には、箔、フィルム等がある。導電性基板の厚さは特に制限されないが、通常は１〜５００μｍ、好ましくは１〜５０μｍ、さらに好ましくは１０〜３０μｍである。   Examples of 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. Although the thickness in particular of an electroconductive board | substrate is not restrict | limited, Usually, 1-500 micrometers, Preferably it is 1-50 micrometers, More preferably, it is 10-30 micrometers.

正極活物質層は、本実施形態では正極集電体の厚さ方向の両方の表面に設けられているが、それに限定されず、正極集電体の厚さ方向の片方の表面に設けられてもよい。正極活物質層は、正極活物質を含み、さらに導電剤、結着剤等を含んでもよい。   In the present embodiment, the positive electrode active material layer is provided on both surfaces in the thickness direction of the positive electrode current collector, but is not limited thereto, and is provided on one surface in the thickness direction of the positive electrode current collector. Also 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.

正極活物質としては、リチウム含有複合金属酸化物、オリビン型リン酸リチウム等が好ましい。   As the positive electrode active material, lithium-containing composite metal oxides, olivine type lithium phosphate and the like are preferable.

リチウム含有複合金属酸化物は、リチウムと遷移金属元素とを含む金属酸化物又は金属酸化物中の遷移金属元素の一部が異種元素によって置換された金属酸化物である。遷移金属元素には、Ｓｃ、Ｙ、Ｍｎ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ｃｒ等があり、Ｍｎ、Ｃｏ、Ｎｉ等が好ましい。異種元素には、Ｎａ、Ｍｇ、Ｚｎ、Ａｌ、Ｐｂ、Ｓｂ、Ｂ等があり、Ｍｇ、Ａｌ等が好ましい。遷移金属元素及び異種元素は、それぞれ１種を単独で又は２種以上を組み合わせて使用できる。   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. Examples of the transition metal element include Sc, Y, Mn, Fe, Co, Ni, Cu, and Cr, and Mn, Co, Ni, and the like are preferable. Examples of different elements include Na, Mg, Zn, Al, Pb, Sb, and B, and Mg, Al, and the like are preferable. A transition metal element and a different element can be used individually by 1 type or in combination of 2 or more types, respectively.

リチウム含有複合酸化物には、ＬｉｌＣｏＯ２、ＬｉｌＮｉＯ２、ＬｉｌＭｎＯ２、ＬｉｌＣｏｍＮｉ１−ｍＯ２、ＬｉｌＣｏｍＡ１−ｍＯｎ、ＬｉｌＮｉ１−ｍＡｍＯｎ、ＬｉｌＭｎ２Ｏ４、ＬｉｌＭｎ２−ｍＡｎＯ４（前記各式中、ＡはＳｃ、Ｙ、Ｍｎ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ｃｒ、Ｎａ、Ｍｇ、Ｚｎ、Ａｌ、Ｐｂ、Ｓｂ及びＢよりなる群から選ばれる少なくとも１つの元素を示す。０＜ｌ≦１．２、ｍ＝０〜０．９、ｎ＝２．０〜２．３である。）等がある。 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 (in the above formulas, A is Sc, Y, Mn, Fe, Co, Ni, Cu, Cr, Na, Mg And at least one element selected from the group consisting of Zn, Al, Pb, Sb and B. 0 <l ≦ 1.2, m = 0 to 0.9, and n = 2.0 to 2.3. .) Etc.

オリビン型リン酸リチウムには、ＬｉＸＰＯ４、Ｌｉ２ＸＰＯ４Ｆ（前記各式中、ＸはＣｏ、Ｎｉ、Ｍｎ及びＦｅよりなる群から選ばれる少なくとも１つの元素を示す。）等がある。 Examples of the olivine type lithium phosphate include LiXPO 4 and Li 2 XPO 4 F (wherein X represents at least one element selected from the group consisting of Co, Ni, Mn and Fe).

前記に例示した正極活物質において、リチウムのモル比は正極活物質作製直後の値であり、充放電により増減する。正極活物質は１種を単独で使用でき又は２種以上を組み合わせて使用できる。   In the positive electrode active material exemplified above, the molar ratio of lithium is a value immediately after the production of the positive electrode active material, and increases or decreases due to charge / discharge. A positive electrode active material can be used individually by 1 type, or can be used in combination of 2 or more type.

導電剤には、例えば、天然黒鉛、人造黒鉛等のグラファイト類、アセチレンブラック、ケッチェンブラック、チャンネルブラック、ファーネスブラック、ランプブラック、サーマルブラック等のカーボンブラック類、炭素繊維、金属繊維等の導電性繊維、アルミニウム等の金属粉末類、フッ化カーボン等がある。導電剤は１種を単独で又は２種以上を組み合わせて使用できる。   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, and conductive properties such as carbon fiber and metal fiber. There are fibers, metal powders such as aluminum, and carbon fluoride. A conductive agent can be used individually by 1 type or in combination of 2 or more types.

結着剤には、樹脂材料を使用できる。樹脂材料には、ポリフッ化ビニリデン、ポリテトラフルオロエチレン、ポリヘキサフルオロプロピレン、ポリエチレン、ポリプロピレン、ポリアミド、ポリイミド、ポリアミドイミド、ポリアクリロニトリル、ポリアクリル酸メチル、ポリアクリル酸エチル、ポリメタクリル酸メチル、ポリメタクリル酸エチル、ポリビニルピロリドン、スチレンブタジエンゴム、変性アクリルゴム、カルボキシメチルセルロース、２種類以上のモノマー化合物を含有する共重合体等がある。   A resin material can be used for the binder. Resin materials include polyvinylidene fluoride, polytetrafluoroethylene, polyhexafluoropropylene, polyethylene, polypropylene, polyamide, polyimide, polyamideimide, polyacrylonitrile, polymethyl acrylate, polyethyl acrylate, polymethyl methacrylate, polymethacrylate Examples include ethyl acid, polyvinyl pyrrolidone, styrene butadiene rubber, modified acrylic rubber, carboxymethyl cellulose, and copolymers containing two or more types of monomer compounds.

モノマー化合物には、テトラフルオロエチレン、ヘキサフルオロプロピレン、ペンタフルオロプロピレン、パーフルオロアルキルビニルエーテル、フッ化ビニリデン、クロロトリフルオロエチレン、エチレン、プロピレン、アクリル酸、ヘキサジエン等がある。   Examples of the monomer compound include tetrafluoroethylene, hexafluoropropylene, pentafluoropropylene, perfluoroalkyl vinyl ether, vinylidene fluoride, chlorotrifluoroethylene, ethylene, propylene, acrylic acid, and hexadiene.

結着剤は１種を単独で又は２種以上を組み合わせて使用できる。   A binder can be used individually by 1 type or in combination of 2 or more types.

正極活物質層は、例えば、正極合剤スラリーを正極集電体表面に塗布し、得られた塗膜を乾燥し、圧延することにより形成できる。正極合剤スラリーは、正極活物質及び導電剤、結着剤等を有機溶媒に溶解又は分散させることにより調製できる。有機溶媒には、ジメチルホルムアミド、ジメチルアセトアミド、メチルホルムアミド、Ｎ−メチル−２−ピロリドン、ジメチルアミン、アセトン、シクロヘキサノン等を使用できる。   The positive electrode active material layer can be formed, for example, by applying a positive electrode mixture slurry to the surface of the positive electrode current collector, drying the obtained coating film, and rolling. The positive electrode mixture slurry can be prepared by dissolving or dispersing a positive electrode active material, a conductive agent, a binder and the like in an organic solvent. As the organic solvent, dimethylformamide, dimethylacetamide, methylformamide, N-methyl-2-pyrrolidone, dimethylamine, acetone, cyclohexanone and the like can be used.

正極リード３６は、抵抗溶接、超音波溶接等により、一端が正極集電体の集電体露出部に接続され、他端が正極端子３３に接続される。正極リード３６の材質は、アルミニウム、アルミニウム合金等である。アルミニウム合金には、アルミニウム−珪素合金、アルミニウム−鉄合金、アルミニウム−銅合金、アルミニウム−マンガン合金、アルミニウム−マグネシウム合金、アルミニウム−亜鉛合金等がある。   The positive electrode lead 36 has one end connected to the current collector exposed portion of the positive electrode current collector and the other end connected to the positive electrode terminal 33 by resistance welding, ultrasonic welding, or the like. The material of the positive electrode lead 36 is aluminum, an aluminum alloy, or the like. Examples of 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.

負極２８は、負極板１と負極リード１３と複数の溶融部１７とを備える。負極２８は、本発明の実施形態の製造方法により作製された負極である。   The negative electrode 28 includes the negative electrode plate 1, the negative electrode lead 13, and a plurality of melting portions 17. The negative electrode 28 is a negative electrode produced by the manufacturing method of the embodiment of the present invention.

セパレータ２９は、正極２７と負極２８との間に介在するように配置される。セパレータ２９には、所定のイオン透過度、機械的強度、絶縁性等を併せ持つシートを使用できる。セパレータ２９には、微多孔膜、織布、不織布等の多孔質シートを使用するのが好ましい。セパレータ２９の材料には各種樹脂材料を使用できるが、耐久性、シャットダウン機能等を考慮すると、ポリエチレン、ポリプロピレン等のポリオレフィンが好ましい。   The separator 29 is disposed so as to be interposed between the positive electrode 27 and the negative electrode 28. As the separator 29, a sheet having predetermined ion permeability, mechanical strength, insulation, and the like can be used. For the separator 29, it is preferable to use a porous sheet such as a microporous film, a woven fabric, and 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 preferable in view of durability, shutdown function and the like.

セパレータ２９の厚さは、通常１０〜３００μｍ、好ましくは１０〜３０μｍ、さらに好ましくは１０〜２５μｍである。また、セパレータ２９の空孔率は好ましくは３０〜７
０％、さらに好ましくは３５〜６０％である。空孔率とは、セパレータ２９の体積に対する、セパレータ２９が有する細孔の総容積の百分率である。 The thickness of the separator 29 is usually 10 to 300 μm, preferably 10 to 30 μm, and more preferably 10 to 25 μm. The porosity of the separator 29 is preferably 30-7.
0%, more preferably 35-60%. The porosity is a percentage of the total volume of the pores of the separator 29 with respect to the volume of the separator 29.

セパレータ２９には、リチウムイオン伝導性を有する液状非水電解質が含浸される。液状非水電解質は、溶質（支持塩）と非水溶媒とを含み、添加剤を含んでもよい。   The separator 29 is impregnated with a liquid non-aqueous electrolyte having lithium ion conductivity. The liquid nonaqueous electrolyte contains a solute (supporting salt) and a nonaqueous solvent, and may contain an additive.

溶質には、ＬｉＣｌＯ４、ＬｉＢＦ４、ＬｉＰＦ６、ＬｉＡｌＣｌ４、ＬｉＳｂＦ６、ＬｉＳＣＮ、ＬｉＣＦ３ＳＯ３、ＬｉＣＦ３ＣＯ２、ＬｉＡｓＦ６、ＬｉＢ１０Ｃｌ１０、低級脂肪族カルボン酸リチウム、ＬｉＣｌ、ＬｉＢｒ、ＬｉＩ、ＬｉＢＣｌ４、ホウ酸塩類、イミド塩類等がある。溶質は、好ましくは０．５〜２モル／Ｌの濃度で非水溶媒に溶解される。 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 , lower aliphatic lithium carboxylate, LiCl, LiBr, Examples include LiI, LiBCl 4 , borate salts, and imide salts. The solute is preferably dissolved in the non-aqueous solvent at a concentration of 0.5 to 2 mol / L.

非水溶媒には、環状炭酸エステル、鎖状炭酸エステル、環状カルボン酸エステル等がある。環状炭酸エステルには、プロピレンカーボネート、エチレンカーボネート等がある。鎖状炭酸エステルには、ジエチルカーボネート、エチルメチルカーボネート、ジメチルカーボネート等がある。環状カルボン酸エステルには、γ−ブチロラクトン、γ−バレロラクトン等がある。非水溶媒は１種を単独で又は２種以上を組み合わせて使用できる。   Nonaqueous solvents include cyclic carbonates, chain carbonates, and cyclic carboxylic acid esters. Examples of the cyclic carbonate include propylene carbonate and ethylene carbonate. Examples of the chain carbonate include diethyl carbonate, ethyl methyl carbonate, dimethyl carbonate and the like. Examples of cyclic carboxylic acid esters include γ-butyrolactone and γ-valerolactone. A non-aqueous solvent can be used individually by 1 type or in combination of 2 or more types.

添加剤には、フッ化エチレンカーボネート、ビニレンカーボネート、ビニルエチレンカーボネート、ジビニルエチレンカーボネート等の充放電効率を向上させる添加剤、シクロヘキシルベンゼン、ビフェニル、ジフェニルエーテル等の電池を不活性化する添加剤等がある。添加剤は１種を単独で又は２種以上を組み合わせて使用できる。   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. . An additive can be used individually by 1 type or in combination of 2 or more types.

上部絶縁板３０、下部絶縁板３１及び封口板３４は、電気絶縁性材料、好ましくは樹脂材料又はゴム材料を所定の形状に成形することにより、作製される。電池ケース３２は長手方向の一方の端部に開口を有する、有底円筒状部材である。電池ケース３２及び正極端子３３は、鉄、ステンレス鋼等の金属材料を所定の形状に成形することにより、作製される。   The upper insulating plate 30, the lower insulating plate 31, and the sealing plate 34 are manufactured by molding an electrically insulating material, preferably a resin material or a rubber material, into a predetermined shape. 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.

本実施形態では、リチウムイオン電池２５は、捲回型電極群２６を含む円筒形電池であるが、それに限定されず、種々の形態を採ることができる。その具体例としては、角形電池、扁平電池、コイン電池、ラミネートフィルムパック電池等が挙げられる。また、捲回型電極群２６に代えて、積層型電極群、扁平状電極群等を用いてもよい。   In the present embodiment, the lithium ion battery 25 is a cylindrical battery including the wound electrode group 26, but is not limited thereto, and can take various forms. 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.

以下に実施例及び比較例を挙げ、本発明を具体的に説明する。   Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.

（実施例１）
（１）正極活物質の作製
ＮｉＳＯ４水溶液に、Ｎｉ：Ｃｏ＝８．５：１．５（モル比）になるように硫酸コバルトを加えて金属イオン濃度２ｍｏｌ／リットルの水溶液を調製した。この水溶液に撹拌下、２ｍｏｌ／リットルの水酸化ナトリウム水溶液を徐々に滴下して中和することにより、Ｎｉ０．８５Ｃｏ０．１５（ＯＨ）２で示される組成を有する三元系の沈殿物を共沈法により生成させた。この沈殿物をろ過により分離し、水洗し、８０℃で乾燥し、複合水酸化物を得た。 Example 1
(1) Preparation NiSO 4 aqueous solution of the positive electrode active material, Ni: Co = 8.5: to prepare an aqueous solution of metal ion concentration 2 mol / l to be 1.5 (mole ratio) was added cobalt sulfate. A ternary precipitate having a composition represented by Ni 0.85 Co 0.15 (OH) 2 is obtained by gradually dropping and neutralizing a 2 mol / liter sodium hydroxide aqueous solution to the aqueous solution while stirring. Was produced by the coprecipitation method. This precipitate was separated by filtration, washed with water, and dried at 80 ° C. to obtain a composite hydroxide.

得られた複合水酸化物を大気中にて９００℃で１０時間加熱して熱処理を行い、Ｎｉ０．８５Ｃｏ０．１５Ｏ２で示される組成を有する複合酸化物を得た。ここでＮｉ及びＣｏの原子数の和とＬｉの原子数とが等量になるように水酸化リチウム１水和物を加え、大気中にて８００℃で１０時間加熱して熱処理を行うことにより、ＬｉＮｉ０．８５Ｃｏ０．
１５Ｏ２で示される組成を有するリチウムニッケル含有複合金属酸化物を得た。こうして、二次粒子の体積平均粒径が１０μｍの正極活物質を得た。 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 . Here, lithium hydroxide monohydrate is added so that the sum of the number of Ni and Co atoms and the number of Li atoms are equal, and heat treatment is performed at 800 ° C. for 10 hours in the air. , LiNi 0.85 Co 0.
A lithium nickel-containing composite metal oxide having a composition represented by 15 O 2 was obtained. In this way, a positive electrode active material having a secondary particle volume average particle size of 10 μm was obtained.

（２）正極の作製
上記で得られた正極活物質の粉末９３ｇ、アセチレンブラック（導電剤）３ｇ、ポリフッ化ビニリデン粉末（結着剤）４ｇ及びＮ−メチル−２−ピロリドン５０ｍｌを充分に混合して正極合剤スラリーを調製した。この正極合剤スラリーを厚さ１５μｍのアルミニウム箔（正極集電体）の両面に塗布し、得られた塗膜を乾燥し、圧延して、片面あたり厚さ５０μｍの正極活物質層を形成し、５６ｍｍ×２０５ｍｍの正極板を作製した。この正極板の両面の正極活物質層の一部（５６ｍｍ×５ｍｍ）を切除し、正極集電体露出部を形成し、アルミニウム製正極リードを超音波溶接により溶接し、正極を作製した。 (2) Production of Positive Electrode 93 g of the positive electrode active material obtained above, 3 g of acetylene black (conductive agent), 4 g of polyvinylidene fluoride powder (binder) and 50 ml of N-methyl-2-pyrrolidone were mixed thoroughly. Thus, a positive electrode mixture slurry was prepared. This positive electrode mixture slurry was applied to both sides of a 15 μm thick aluminum foil (positive electrode current collector), and the resulting coating film was dried and rolled to form a positive electrode active material layer having a thickness of 50 μm per side. A positive electrode plate of 56 mm × 205 mm was produced. A part (56 mm × 5 mm) of the positive electrode active material layer on both surfaces of the positive electrode plate was excised to form a positive electrode current collector exposed portion, and an aluminum positive electrode lead was welded by ultrasonic welding to produce a positive electrode.

（３）負極板の作製
図４は、電子ビーム式真空蒸着装置４０の構成を模式的に示す側面図である。図４では、電子ビーム式真空蒸着装置４０の内部の部材を実線で示している。真空チャンバー４１は耐圧性容器であり、その内部に、搬送手段４２、ガス供給手段４８、プラズマ化手段４９、シリコンターゲット５０ａ、５０ｂ、遮蔽板５１及び電子ビーム発生装置（図示しない）を収容する。 (3) Production of Negative Electrode Plate FIG. 4 is a side view schematically showing the configuration of the electron beam vacuum deposition apparatus 40. In FIG. 4, members inside the electron beam vacuum deposition apparatus 40 are indicated by solid lines. 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).

搬送手段４２は、巻き出しローラ４３、キャン４４、巻き取りローラ４５及び案内ローラ４６、４７を含む。巻き出しローラ４３には、帯状の負極集電体１０が捲き付けられる。帯状の負極集電体１０は、案内ローラ４６、キャン４４及び案内ローラ４７を経由して搬送され、負極板１として巻き取りローラ４５に巻き取られる。   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 strip-shaped negative electrode current collector 10 is conveyed via the guide roller 46, the can 44 and the guide roller 47, and is wound around the winding roller 45 as the negative electrode plate 1.

帯状の負極集電体１０がキャン４４の表面を搬送される際に、帯状の負極集電体１０の表面に珪素の蒸気が供給される。珪素の蒸気はキャン４４内部の図示しない冷却手段により冷却されて帯状の負極集電体１０の表面に析出し、ベタ膜である薄膜状負極活物質層１１が形成される。珪素の蒸気は、シリコンターゲット５０ａ、５０ｂに、電子ビーム発生装置から電子ビームを照射することにより生成する。   When the strip-shaped negative electrode current collector 10 is conveyed on the surface of the can 44, silicon vapor is supplied to the surface of the strip-shaped negative electrode current collector 10. The silicon vapor is cooled by a cooling means (not shown) inside the can 44 and is deposited on the surface of the strip-shaped negative electrode current collector 10 to form the thin film negative electrode active material layer 11 which is a solid film. Silicon vapor is generated by irradiating the silicon targets 50a and 50b with an electron beam from an electron beam generator.

ガス供給手段４８は、原料ガスを真空チャンバー４１内に供給する。原料ガスが酸素である場合、珪素の蒸気と酸素との混合物が帯状の負極集電体１０の表面に供給され、珪素酸化物を含有する薄膜状負極活物質層１１が形成される。ガス供給手段４８が原料ガスを供給しない場合は、珪素を含有する薄膜状負極活物質層１１が形成される。プラズマ化手段４９は、原料ガスをプラズマ化する。負極集電体１０表面の薄膜状負極活物質層１１の形成状況に応じて、遮蔽板５１の水平方向の位置が調整される。   The gas supply means 48 supplies the source gas into the vacuum chamber 41. When the source gas is oxygen, a mixture of silicon vapor and oxygen is supplied to the surface of the strip-shaped negative electrode current collector 10 to form the thin film negative electrode active material layer 11 containing silicon oxide. When the gas supply means 48 does not supply the source gas, the thin film negative electrode active material layer 11 containing silicon is formed. The plasma generating means 49 converts the raw material gas into plasma. The horizontal position of the shielding plate 51 is adjusted according to the formation state of the thin film negative electrode active material layer 11 on the surface of the negative electrode current collector 10.

電子ビーム式真空蒸着装置４０を用いて、下記の条件で、帯状負極集電体の両方の表面に、厚さ５μｍの薄膜状負極活物質層（シリコン薄膜）を形成し、負極板を作製した。   Using the electron beam type vacuum vapor deposition apparatus 40, a thin-film negative electrode active material layer (silicon thin film) having a thickness of 5 μm was formed on both surfaces of the strip-shaped negative electrode current collector under the following conditions to produce a negative electrode plate. .

真空チャンバー内の圧力：８．０×１０−５Ｔｏｒｒ
帯状負極集電体：粗面化処理した電解銅箔（古河電工（株）製）
帯状負極集電体の巻き取りローラによる巻き取り速度：２ｃｍ／分
原料ガス：供給せず。 Pressure in the vacuum chamber: 8.0 × 10 −5 Torr
Strip-shaped negative electrode current collector: roughened electrolytic copper foil (Furukawa Electric Co., Ltd.)
Winding speed of belt-shaped negative electrode current collector by winding roller: 2 cm / min. Source gas: not supplied.

シリコンターゲット：純度９９．９９９９％のシリコン単結晶（信越化学工業（株）製）
電子ビームの加速電圧：−８ｋＶ
電子ビームのエミッション：３００ｍＡ
得られた負極板を５８ｍｍ×２１０ｍｍに裁断した。この負極板を、タンタル製ボード
と薄膜状負極活物質層とが対向するように、抵抗加熱蒸着装置（（株）アルバック製）内に固定した。タンタル製ボードには、リチウム金属を装填した。抵抗加熱蒸着装置内にアルゴン雰囲気を導入し、タンタル製ボートに５０Ａの電流を通電し、薄膜状負極活物質層にリチウムを蒸着した。蒸着時間は１０分であった。これにより、初回充放電時に蓄えられる不可逆容量分のリチウムを薄膜状負極活物質層に補填した。 Silicon target: Silicon single crystal with a purity of 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 was cut into 58 mm × 210 mm. This negative electrode plate 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 face each other. The tantalum board was loaded with lithium metal. An argon atmosphere was introduced into the resistance heating vapor deposition apparatus, a 50 A current was passed through the tantalum boat, and lithium was deposited on the thin film negative electrode active material layer. The deposition time was 10 minutes. Thereby, lithium for the irreversible capacity stored at the time of the first charge / discharge was supplemented to the thin film negative electrode active material layer.

（４）負極リードの接合
上記で得られた負極板に、銅箔（タフピッチ銅、日立電線（株）製）を裁断して作製された、幅５ｍｍ、長さ７０ｍｍ、厚さ０．１ｍｍの負極リードを、次のようにしてプラズマ溶接により接合し、負極を作製した。 (4) Bonding of negative electrode lead The negative electrode plate obtained above was prepared by cutting a copper foil (tough pitch copper, manufactured by Hitachi Cable Ltd.), having a width of 5 mm, a length of 70 mm, and a thickness of 0.1 mm. The negative electrode lead was joined by plasma welding as follows to produce a negative electrode.

まず、負極板の長手方向の一端面と、負極リードの幅方向の一端面とが、連続した１つの平面になり、平坦な溶接端面が形成されるように、負極板と負極リードとを重ね合せた。溶接端面に垂直な方向を鉛直方向に一致させ、溶接端面が鉛直方向横方を臨むように配置した。これらを、図１に示す一組の溶接治具で挟持し、さらに単軸ロボット（（株）アイエイアイ製）で固定した。   First, the negative electrode plate and the negative electrode lead are overlapped so that one end surface in the longitudinal direction of the negative electrode plate and one end surface in the width direction of the negative electrode lead form one continuous plane, and a flat weld end surface is formed. Combined. The direction perpendicular to the weld end face was made to coincide with the vertical direction, and the weld end face was arranged to face the vertical direction side. These were clamped by a set of welding jigs shown in FIG. 1 and further fixed by a single-axis robot (manufactured by IAI Corporation).

溶接治具は、第１板及び第２板からなり、第１板及び第２板の寸法は１００ｍｍ×４０ｍｍ×１０ｍｍであり、いずれも銅製であった。また、第１板に形成された第１凹部及び第２板に形成された第２凹部である切欠きの断面形状はテーパ形状であり、切かきの断面寸法は、第１板又は第２板の端面に沿う方向の長さが０．５ｍｍであり、第１板又は第２板の合わせ面に沿う方向の長さが０．５ｍｍであった。   The welding jig was composed of a first plate and a second plate, and the dimensions of the first plate and the second plate were 100 mm × 40 mm × 10 mm, both of which were made of copper. Moreover, the cross-sectional shape of the notch which is the 1st recessed part formed in the 1st board and the 2nd recessed part formed in the 2nd board is a taper shape, and the cross-sectional dimension of a notch is the 1st board or the 2nd board. The length in the direction along the end surface of the first plate was 0.5 mm, and the length in the direction along the mating surface of the first plate or the second plate was 0.5 mm.

次に、プラズマ溶接機（商品名：ＰＷ−５０ＮＲ、小池酸素工業（株）製）を、溶接端面の鉛直方向横に配置した。このプラズマ溶接機のトーチから、溶接端面に対して垂直にエネルギーを照射した。トーチを負極リード中心に幅７ｍｍ移動させた。溶接端面に下記の条件でエネルギーを照射し、合金層を形成し、負極を作製した。   Next, a plasma welding machine (trade name: PW-50NR, manufactured by Koike Oxygen Industry Co., Ltd.) was placed beside the welding end face in the vertical direction. Energy was irradiated from the torch of this plasma welding machine perpendicularly to the weld end face. The torch was moved 7 mm in width to the center of the negative electrode lead. The weld end face was irradiated with energy under the following conditions, an alloy layer was formed, and a negative electrode was produced.

電極棒：直径１．０ｍｍ
電極ノズル：直径１．６ｍｍ
トーチ距離：２．０ｍｍ
トーチ掃引速度：３０ｍｍ／ｓ
トーチ送引幅：７ｍｍ
プラズマガス：アルゴン
プラズマガス流量：１００（ｓｃｃｍ）
シールドガス：水素、アルゴン
シールドガス流量（水素）：５００（ｓｃｃｍ）
シールドガス流量（アルゴン）：１（ｓｌｍ）
溶接電流：８．０Ａ
プラズマ溶接後に、自然放冷し、溶接端面をレーザ顕微鏡（商品名：ＶＫ９７００、（株）キーエンス製）で観察した。その結果、負極リードが負極板に対向している領域から、負極リードが対向していない領域まで連続した溶融部が形成されていることが確認された。負極リードが対向していない負極板の溶融幅は３ｍｍであった。 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)
Shielding gas flow rate (argon): 1 (slm)
Welding current: 8.0A
After plasma welding, it was allowed to cool naturally, and the weld end face was observed with a laser microscope (trade name: VK9700, manufactured by Keyence Corporation). As a result, it was confirmed that a continuous melted portion was formed from a region where the negative electrode lead was opposed to the negative electrode plate to a region where the negative electrode lead was not opposed. The melt width of the negative electrode plate with the negative electrode lead not facing was 3 mm.

走査型電子顕微鏡（３Ｄリアルサーフェースビュー）にエネルギー分散型Ｘ線分析装置（商品名：Ｇｅｎｅｓｉｓ ＸＭ２、ＥＤＡＸ社製）を装着し、溶融部の断面の銅及び珪素の元素マップを調べた。その結果、溶融部断面のほぼ全領域に、銅及び珪素が存在していた。また、エネルギー分散型Ｘ線分析装置（Ｇｅｎｅｓｉｓ ＸＭ２）により、溶融部の所定の部分で銅と珪素との元素モル比率を測定した結果、銅が９５モル％、珪素が５モル％であった。これらの結果から、銅中に珪素が拡散し、合金を形成していることが判っ
た。 An energy dispersive X-ray analyzer (trade name: Genesis XM2, manufactured by EDAX) was attached to a scanning electron microscope (3D real surface view), and an elemental map of copper and silicon in the cross section of the molten part was examined. As a result, copper and silicon were present in almost the entire region of the melted section. Moreover, as a result of measuring the element molar ratio of copper and silicon in the predetermined part of the fusion | melting part with the 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.

溶融部の断面を、微小部Ｘ線回折装置（商品名：ＲＩＮＴ２５００、理学電機（株）製）により定性分析した。その結果、溶融部から、銅のピーク及びＣｕ５Ｓｉのピークが同定された。したがって、溶融部には、Ｃｕ５Ｓｉ合金が含まれていることが判った。 The cross section of the melted part 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. Therefore, it was found that the molten portion contained a Cu 5 Si alloy.

さらに、溶融部の断面について、オージェ電子分光装置（商品名：ＭＯＤＥＬ６７０、ＵＬＶＡＣ ＰＨＩ社製）によりリチウムの元素マップを調べた。溶融部の断面の周縁部には、溶融部の断面に比べて寸法が非常に小さい薄膜状負極活物質層の断面及びシリコン層の断面が存在した。薄膜状負極活物質層は、溶融せずに残存した部分である。シリコン層は、１度溶融して、合金化せずに再凝固した部分である。これらの断面にはリチウムが存在したが、銅及び銅合金の断面にはリチウムは存在しなかった。   Furthermore, the elemental map of lithium was investigated about the cross section of the fusion | melting part with the Auger electron spectroscope (brand name: MODEL670, ULVAC PHI make). The cross section of the thin-film negative electrode active material layer and the cross section of the silicon layer existed at the peripheral edge of the cross section of the melted portion, the dimensions being very small compared to the cross section of the melted portion. The thin film negative electrode active material layer is a portion remaining without melting. The silicon layer is a portion that has been melted once and re-solidified without being alloyed. Lithium was present in these cross sections, but no lithium was present in the cross sections of copper and copper alloys.

以上の分析結果から、合金層には、銅と、Ｃｕ５Ｓｉを含む銅−シリコン合金とが存在し、合金層断面の周縁部にはシリコンとリチウムが存在することがわかった。 From the above analysis results, it was found that copper and a copper-silicon alloy containing Cu 5 Si exist in the alloy layer, and silicon and lithium exist in the peripheral portion of the alloy layer cross section.

（５）電池の作製
上記で得られた正極と負極との間にポリエチレン微多孔膜（セパレータ、商品名：ハイポア、厚さ２０μｍ、旭化成（株）製）を介在させて積層し、得られた積層物を捲回し、捲回型電極群を作製した。正極リードの他端をステンレス鋼製正極端子に溶接し、負極リードの他端を有底円筒形の鉄製電池ケースの底部内面に接続した。捲回型電極群の長手方向の一端部及び他端部に、それぞれ、ポリエチレン製の上部絶縁板及び下部絶縁板を装着し、電池ケース内に収容した。 (5) Fabrication of battery A polyethylene microporous membrane (separator, trade name: Hypore, thickness 20 μm, manufactured by Asahi Kasei Co., Ltd.) was interposed between the positive electrode and the negative electrode obtained above and obtained. The laminate was wound to produce a wound electrode group. The other end of the positive electrode lead was welded to a stainless steel positive electrode terminal, and the other end of the negative electrode lead was connected to the bottom inner surface of a bottomed cylindrical iron battery case. An upper insulating plate and a lower insulating plate made of polyethylene were attached to one end and the other end in the longitudinal direction of the wound electrode group, respectively, and accommodated in the battery case.

次に、エチレンカーボネートとエチルメチルカーボネートとを体積比１：１の割合で含む混合溶媒に、ＬｉＰＦ６を１．０ｍｏｌ／Ｌの濃度で溶解させた非水電解液を電池ケースに注液した。さらに、電池ケースの開口に、ポリエチレン製のガスケットを介して封口板を装着し、電池ケースの開口端部を内側にかしめて電池ケースを封口し、円筒型リチウムイオン電池を作製した。 Next, a non-aqueous electrolyte solution in which LiPF 6 was dissolved 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 was poured into the battery case. Furthermore, a sealing plate was attached to the opening of the battery case via a polyethylene gasket, and the battery case was sealed by crimping the opening end of the battery case inward to produce a cylindrical lithium ion battery.

（比較例１）
トーチの送引幅を負極リード中心に２ｍｍとして負極を作製する以外は実施例１と同様にして、円筒リチウムイオン電池を作製した。 (Comparative Example 1)
A cylindrical lithium ion battery was produced in the same manner as in Example 1 except that the negative electrode was produced with the torch feed width of 2 mm at the center of the negative electrode lead.

プラズマ溶接後に、自然放冷し、溶接端面をレーザ顕微鏡（商品名：ＶＫ９７００、キーエンス社製）で観察した。その結果、負極リードと負極板の溶融幅は４ｍｍで負極リードの端部は溶融しておらず、負極リードが対向していない負極板に溶融は確認されなかった。   After plasma welding, it was allowed to cool naturally, and the weld end face was observed with a laser microscope (trade name: VK9700, manufactured by Keyence Corporation). As a result, the melting width of the negative electrode lead and the negative electrode plate was 4 mm, the end of the negative electrode lead was not melted, and no melting was confirmed in the negative electrode plate where the negative electrode lead was not opposed.

（比較例２）
負極リードの負極集電体への接合方法をプラズマ溶接から抵抗溶接に変更して負極を作製する以外は、実施例１と同様にして円筒型リチウムイオン電池を作製した。なお、負極の作製は次のようにして実施した。 (Comparative Example 2)
A cylindrical lithium ion battery was produced in the same manner as in Example 1 except that the negative electrode was produced by changing the joining method of the negative electrode lead to the negative electrode current collector from plasma welding to resistance welding. The negative electrode was produced as follows.

まず、実施例１と同様にして得られた負極板と銅製の負極リード（幅４ｍｍ、長さ７０ｍｍ、厚さ１００μｍ）とを、負極板の長手方向の端面と負極リードの幅方向の端面とが１つの連続した平面になるように隣接配置した。これらの負極板及び負極リードを、先端径２ｍｍの電極棒で挟持し、抵抗溶接機（ミヤチテクノス（株）製）を用いて、電流値を１．３ｋＡに設定してスポット溶接を行い、負極を作製した。   First, a negative electrode plate obtained in the same manner as in Example 1 and a copper negative electrode lead (width 4 mm, length 70 mm, thickness 100 μm), the end surface in the longitudinal direction of the negative electrode plate and the end surface in the width direction of the negative electrode lead Are arranged adjacent to each other so as to be one continuous plane. The negative electrode plate and the negative electrode lead are sandwiched between electrode rods having a tip diameter of 2 mm, and spot welding is performed using a resistance welding machine (manufactured by Miyachi Technos Co., Ltd.) with the current value set to 1.3 kA. Was made.

［負極集電体と負極リードとの接合強度］
実施例１及び比較例１〜２で得られた負極について、次のようにして負極集電体と負極リードとの接合強度を、負極リードの負極集電体に対する引張強度として測定した。図５は、負極リード１３の負極集電体１０に対する引張強度を測定するための試料の作製方法を示す斜視図である。図６は、負極リード１３の負極集電体１０に対する引張強度の測定方法を示す斜視図である。 [Joint strength between negative electrode current collector and negative electrode lead]
About the negative electrode obtained in Example 1 and Comparative Examples 1 and 2, the bonding strength between the negative electrode current collector and the negative electrode lead was measured as the tensile strength of the negative electrode lead with respect to the negative electrode current collector as follows. FIG. 5 is a perspective view showing a method for preparing a sample 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 showing a method for measuring the tensile strength of the negative electrode lead 13 with respect to the negative electrode current collector 10.

図５（ａ）に示すように、まず、負極リード１３の長さが、負極板１の幅と同じになるように、負極リード１３を切断した。次に、負極板１の長さが、負極リード１３が接合されている端部から３０ｍｍになるように、負極板１を切断した。このとき、接合幅ｄを測定した。接合幅ｄは、負極板１と負極リード１３とが対向した領域で、かつ溶融している領域の長さである。   As shown in FIG. 5A, first, 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. Next, the negative electrode plate 1 was cut so that the length of the negative electrode plate 1 was 30 mm from the end where the negative electrode lead 13 was joined. At this time, the bonding width d was measured. The bonding width d is a length of a region where the negative electrode plate 1 and the negative electrode lead 13 are opposed to each other and a melted region.

複数の溶融部１７が所定の間隔を空けて形成されている場合、接合幅ｄは、負極板１の幅方向の一端に形成された溶融部１７から、他端に形成された溶融部１７までの長さである。この場合、一端及び他端に形成された溶融部１７の長さを、接合幅ｄに含めている。実施例１及び比較例１〜２で得られた負極それぞれの接合幅ｄを３０ｍｍに切断した。引き続き、図５（ｂ）に示すように、負極リード１３を負極板１から剥がすように、矢印６６の方向に折り返し、引張強度測定用の試料６５を作製した。   When the plurality of melting portions 17 are formed at predetermined intervals, the bonding width d ranges from the melting portion 17 formed at one end in the width direction of the negative electrode plate 1 to the melting portion 17 formed at the other end. Is the length of In this case, the length of the melting part 17 formed at one end and the other end is included in the joining width d. The junction width d of each negative electrode obtained in Example 1 and Comparative Examples 1 and 2 was cut to 30 mm. Subsequently, as shown in FIG. 5B, the negative electrode lead 13 was folded in the direction of the arrow 66 so as to peel off the negative electrode plate 1, thereby preparing a sample 65 for measuring tensile strength.

得られた試料６５を用い、図６に示す測定方法により、引張強度を測定した。万能試験機（（株）島津製作所製）７０の下部固定治具７１に、負極板１の溶融部１７が形成されていない側の端部を挟んで固定し、上部固定治具７２に負極リード１３の溶融部１７が形成されていない側の端部（折り返し側の端部）を挟んで固定した。   Using the obtained sample 65, the tensile strength was measured by the measuring method shown in FIG. Fixed to the lower fixing jig 71 of the universal testing machine (manufactured by Shimadzu Corp.) 70 with the end of the negative electrode plate 1 on the side where the melted portion 17 is not formed sandwiched, and the negative electrode lead to the upper fixing jig 72 13 end portions on the side where the melted portions 17 are not formed (end portions on the folded side) are fixed.

室温２５℃にて、上部固定治具７２を５ｍｍ／分の速度で矢印７３の方向に移動させて負極リード１３を引っ張った。そして、負極板１と負極リード１３との接合部分（溶融部１７）が破断したときの引張強度（Ｎ）を測定した。得られた引張強度の測定値と接合幅ｄの測定値とから、接合幅１ｍｍ当たりの引張強度（Ｎ／ｍｍ）を求めた。結果を表１に示す。   At a room temperature of 25 ° C., the upper fixing jig 72 was moved in the direction of the arrow 73 at a speed of 5 mm / min to pull the negative electrode lead 13. And the tensile strength (N) when the junction part (melting part 17) of the negative electrode plate 1 and the negative electrode lead 13 fractured | ruptured 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.

［負極集電体と負極リードとの導通性］
実施例１及び比較例１〜２で得られた負極について、次のようにして負極集電体と負極リードとの接合抵抗を測定した。負極リード近傍の薄膜状負極活物質層を、サンドペーパーを用いて剥離した。次に、露出した負極集電体と負極リードとの接合抵抗を、ミリオームメーター（商品名：ミリオームハイテスタ３５４０、日置電機（株）製）を用いて測定した。結果を表１に示す。 [Conductivity between negative electrode current collector and negative electrode lead]
For the negative electrodes obtained in Example 1 and Comparative Examples 1 and 2, the junction resistance between the negative electrode current collector and the negative electrode lead was measured as follows. The thin film negative electrode active material layer in the vicinity of the negative electrode lead was peeled off using sandpaper. Next, the junction resistance between the exposed negative electrode current collector 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.

［電極群構成時の電極変形］
実施例１及び比較例１〜２で得られた円筒型リチウムイオン電池２０セルを分解し、負極リードの接続状態を観察した。接合部付近に亀裂や破断が見られたセル数またはセパレータに損傷が見られたセル数を数え、不良セル数とした。結果を表１に示す。 [Electrode deformation during electrode group configuration]
The cylindrical lithium ion battery 20 cells obtained in Example 1 and Comparative Examples 1 and 2 were disassembled, and the connection state of the negative electrode lead was observed. The number of cells in which cracks or breaks were observed in the vicinity of the joint or the number of cells in which the separator was damaged was counted as the number of defective cells. The results are shown in Table 1.

表１における実施例１の結果から、溶融部による負極集電体と負極リードとの接合により、負極集電体と負極リードとの間で、良好な接合性及び導通性が得られることがわかる。比較例１では、負極集電体と負極リードとの接合部に亀裂が観察されたことから、断線する不具合が起こりやすいことが判明した。   From the results of Example 1 in Table 1, it can be seen that good bondability and electrical conductivity can be obtained between the negative electrode current collector and the negative electrode lead by bonding the negative electrode current collector and the negative electrode lead by the melting part. . In Comparative Example 1, since it was observed that a crack was observed at the joint between the negative electrode current collector and the negative electrode lead, it was found that the problem of disconnection was likely to occur.

一方、抵抗溶接を実施した比較例２では、導通性を有する接合が出来なかったことが明らかである。このことから、抵抗溶接では、負極リードを負極集電体に接合できないことが判った。   On the other hand, in Comparative Example 2 in which resistance welding was performed, it is clear that the joining having conductivity was not possible. From this, it was found that resistance welding cannot bond the negative electrode lead to the negative electrode current collector.

（試験例２）
［サイクル特性］
実施例１及び比較例１〜２のリチウムイオン電池を各条件３個ずつ、それぞれ２０℃の恒温槽に収容し、以下のような定電流定電圧方式で、電池を充電した。 (Test Example 2)
[Cycle characteristics]
Three lithium ion batteries of Example 1 and Comparative Examples 1 and 2 were housed in a constant temperature bath of 20 ° C., respectively, and the batteries were charged by the following constant current and constant voltage method.

各電池を、電池電圧が４．２Ｖになるまで１Ｃレート（１Ｃとは１時間で全電池容量を使い切ることができる電流値）の定電流で充電した。電池電圧が４．２Ｖに達した後は、電流値が０．０５Ｃになるまで、各電池を４．２Ｖの定電圧で充電した。次に、２０分間休止した後、充電後の電池を、１Ｃレートのハイレートの定電流で、電池電圧が２．５Ｖになるまで放電した。このような充放電を１００サイクル繰り返した。   Each 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.

１サイクル目の全放電容量に対する、１００サイクル目の全放電容量の割合を、百分率値で求めた。得られた値の平均値を算出し、容量維持率として表２に示す。   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 is calculated and shown in Table 2 as a capacity maintenance rate.

実施例１及び比較例１の電池は、容量維持率が高く、良好なサイクル特性を有することが判った。特に、実施例１の電池は、さらに高い容量維持率を示した。比較例１の電池は、１セルが抵抗無限大を示し、分解観察の結果リードが破断していることがわかった。一方、比較例２の電池は、通電することができず、抵抗が無限大となった。分解観察の結果、比較例１と同様にリードが破断していることがわかった。   The batteries of Example 1 and Comparative Example 1 were found to have a high capacity retention rate and good cycle characteristics. In particular, the battery of Example 1 exhibited a higher capacity retention rate. In the battery of Comparative Example 1, one cell showed infinite resistance, and as a result of disassembly observation, it was found that the lead was broken. On the other hand, the battery of Comparative Example 2 could not be energized, and the resistance was infinite. As a result of the decomposition observation, it was found that the lead was broken as in Comparative Example 1.

本発明の負極の製造方法により得られる負極は、リチウムイオン電池の負極として好適に使用できる。また、本発明のリチウムイオン電池は、従来のリチウムイオン電池と同様
の用途に使用でき、特に、携帯用電子機器の電源として有用である。携帯用電子機器には、例えば、パーソナルコンピュータ、携帯電話、モバイル機器、携帯情報端末（ＰＤＡ）、携帯用ゲーム機器、ビデオカメラ等がある。また、本発明のリチウムイオン電池は、ハイブリッド電気自動車、電気自動車、燃料電池自動車等の主電源及び補助電源、電動工具、掃除機、ロボット等の駆動用電源、プラグインＨＥＶの動力源等としての利用も期待される。 The negative electrode obtained by the negative electrode manufacturing method of the present invention can be suitably used as a negative electrode for a lithium ion battery. In addition, the lithium ion battery of the present invention can be used for 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 of the present invention is used as a main power source and auxiliary power source for hybrid electric vehicles, electric vehicles, fuel cell vehicles, etc., driving power sources for electric tools, vacuum cleaners, robots, etc., power sources for plug-in HEVs, etc. Use is also expected.

１ 負極板
１ａ 負極板端面
１０ 負極集電体
１１ 薄膜状負極活物質層
１３ 負極リード
１３ａ 負極リード端面
１４ 溶接治具
１７ 溶融部
２０ 第１板
２０ｘ 第１凹部
２１ 第２板
２１ｘ 第２凹部
２３ 平面加圧治具
２５ リチウムイオン電池
４０ 電子ビーム式真空蒸着装置 DESCRIPTION OF SYMBOLS 1 Negative electrode plate 1a Negative electrode plate end surface 10 Negative electrode collector 11 Thin film negative electrode active material layer 13 Negative electrode lead 13a Negative electrode lead end surface 14 Welding jig 17 Melting part 20 1st board 20x 1st recessed part 21 2nd board 21x 2nd recessed part 23 Flat pressure jig 25 Lithium ion battery 40 Electron beam vacuum deposition equipment

Claims (7)

集電体及び前記集電体の表面に形成される薄膜状負極活物質層を備え、前記薄膜状負極活物質層が合金系活物質を含有する負極板と、
前記負極板に接続される負極リードと、
前記負極板の端面と前記負極リードの端面との間に介在しこれらを溶接する溶融部を有するリチウムイオン電池用負極であって、
前記溶融部は、前記負極リードの幅より溶融領域が広く、前記負極リードが対向しない前記負極板の端面の少なくとも一部にも設けられているリチウムイオン電池用負極。 A negative electrode plate comprising a current collector and a thin film negative electrode active material layer formed on a surface of the current collector, wherein the thin film negative electrode active material layer contains an alloy-based active material;
A negative electrode lead connected to the negative electrode plate;
A negative electrode for a lithium ion battery having a fusion zone interposed between an end face of the negative electrode plate and an end face of the negative electrode lead and welding them,
The melting part has a melting region wider than the width of the negative electrode lead, and the negative electrode for a lithium ion battery is also provided on at least a part of an end surface of the negative electrode plate where the negative electrode lead does not face. 前記負極リードが対向しない前記負極板の端面の少なくとも一部に設けられた溶融部の幅が、０．１ｍｍ以上、１０ｍｍ以下である請求項１記載のリチウムイオン電池用負極。   2. The negative electrode for a lithium ion battery according to claim 1, wherein a width of a melted portion provided on at least a part of an end face of the negative electrode plate that does not face the negative electrode lead is 0.1 mm or more and 10 mm or less. 前記溶融部が連続的に設けられている請求項１または２に記載のリチウムイオン電池用負極。   The negative electrode for a lithium ion battery according to claim 1, wherein the melting part is continuously provided. 前記負極リードが対向しない前記負極板の端面の溶融部は、前記合金系活物質の元素と前記集電体の元素からなる合金を含有する請求項１〜３のいずれかに記載のリチウムイオン電池用負極。   The lithium ion battery according to any one of claims 1 to 3, wherein a melted portion of an end face of the negative electrode plate that is not opposed to the negative electrode lead contains an alloy composed of an element of the alloy-based active material and an element of the current collector. Negative electrode. 前記合金系活物質の元素が珪素または錫であり、前記集電体の金属元素が銅またはニッケルである請求項４に記載の負極。   The negative electrode according to claim 4, wherein the element of the alloy-based active material is silicon or tin, and the metal element of the current collector is copper or nickel. 前記溶融部の溶接強度が０．５Ｎ／ｍｍ以上、５０Ｎ／ｍｍ以下である請求項１〜５のいずれかに記載のリチウムイオン電池用負極。   The negative electrode for a lithium ion battery according to any one of claims 1 to 5, wherein the weld strength of the molten part is 0.5 N / mm or more and 50 N / mm or less. 正極集電体、前記正極集電体の表面に形成される正極活物質及び前記正極集電体に接続される正極リードを備える正極と、
請求項１〜６のいずれかに記載のリチウムイオン電池用負極と、
前記正極と前記リチウムイオン電池用負極との間に介在するように配置されるセパレータと、
リチウムイオン伝導性非水電解質と、を備えるリチウムイオン電池。 A positive electrode comprising a positive electrode current collector, a positive electrode active material formed on a surface of the positive electrode current collector, and a positive electrode lead connected to the positive electrode current collector;
A negative electrode for a lithium ion battery according to any one of claims 1 to 6,
A separator disposed so as to be interposed between the positive electrode and the negative electrode for a lithium ion battery;
A lithium ion battery comprising: a lithium ion conductive nonaqueous electrolyte.
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