JP2004220953A - Manufacturing method of lithium secondary battery - Google Patents

Manufacturing method of lithium secondary battery Download PDF

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JP2004220953A
JP2004220953A JP2003007921A JP2003007921A JP2004220953A JP 2004220953 A JP2004220953 A JP 2004220953A JP 2003007921 A JP2003007921 A JP 2003007921A JP 2003007921 A JP2003007921 A JP 2003007921A JP 2004220953 A JP2004220953 A JP 2004220953A
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negative electrode
electrode current
secondary battery
lithium secondary
collecting member
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Shinji Otsubo
真治 大坪
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NGK Insulators Ltd
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NGK Insulators Ltd
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    • 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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  • Connection Of Batteries Or Terminals (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a lithium secondary battery with an excellent productivity. <P>SOLUTION: The lithium secondary battery is manufactured by forming a wound inside electrode body or the like by winding a positive electrode plate 1A and a negative electrode plate through a separator, and connecting end parts of the positive electrode plate 1A and the negative electrode plate to a positive electrode current collecting member 4A made of aluminum or the like and a negative electrode current collecting member made of copper, respectively. The surface of respective connection parts 5 of the positive electrode current collecting member 4A and/or the negative electrode current collecting member are processed so as to have a center line average surface coarseness of 0.05 to 6.3 μmRa. The connection parts 5 of the positive electrode current collecting member 4A is fused and welded to the end part 15 of the positive electrode plate 1A by a laser beam having a power density of 5 kW/mm<SP>2</SP>or higher, and/or the connection parts of the negative electrode current collecting member is fused and welded to the end part of the negative electrode plate by a laser beam having a power density of 3 kW/mm<SP>2</SP>or higher. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】本発明は、リチウム二次電池（以下、単に「電池」ともいう）の製造方法に関し、さらに詳しくは、生産性に優れたリチウム二次電池の製造方法に関する。
【０００２】
【従来の技術】近年、国際的な地球環境の保護のための省資源化や省エネルギー化の要請が高まり、電気自動車やハイブリッド電気自動車（以下、単に「電気自動車等」ともいう）のモータ駆動用電源として、リチウム二次電池の開発が進められている。
【０００３】このリチウム二次電池は、その内部に正極板と負極板とを多孔性ポリマーフィルムからなるセパレータを介して正極板と負極板とが直接に接触しないように捲回又は積層して構成された内部電極体（以下、単に「電極体」ともいう）を備えている。
【０００４】従来、図１９に示すように、例えば、捲回型の内部電極体６１には、正極板６２と負極板６３とをセパレータ６４を介して、巻芯６７を芯として捲回して作製され、正極板６２及び負極板６３（以下、「電極板６２、６３」ともいう）のそれぞれに、少なくとも１枚の正極用の集電タブ６５及び負極用の集電タブ６６（以下、「集電タブ６５、６６」ともいう）が配設される（例えば、特許文献１参照）。そして、図１８に示すように、集電タブ６５、６６の、正極板６２及び負極板６３（図１９参照）と接続された反対側の端部は、内部端子６９Ａ、６９Ｂ等に取り付けられる。
【０００５】なお、符号７６は弾性体（パッキン）を、符号７７は絶縁性ポリマーフィルムを、符号７８は放圧弁を、符号７９は金属箔を示す。また、その他の符号はそれぞれ後述する図３に記載の符号と同じものを示している。
【０００６】電極板としては、正極板にアルミニウム等、負極板に銅、ニッケル等の金属箔体等を集電基板として用い、それぞれに電極活物質を塗布して形成されており、集電タブは、このような集電基板の少なくとも一辺に配設される。
【０００７】しかし、集電タブは、電極体を捲回するときに、ひとつずつ電極板にスポット溶接等して取り付ける必要があるために、その工程は煩雑であるという問題があった。また、集電タブの、電極板と接続された反対側の端部は、それら複数の集電タブを揃えて束ね、内部端子にリベット等を用いて打ち込み接続等して取り付ける必要があるために、その工程も同様に煩雑であり、また低抵抗に接続することは容易ではないという問題があった。
【０００８】
【特許文献１】
特開２００１−８５０４２号公報
【０００９】
【発明が解決しようとする課題】本発明は、かかる従来の問題に鑑みてなされたものであり、その目的とするところは、各電極板の端部と集電部材を直接的に接続して内部電極体から電流を導出するという構成を採用し、各電極板と集電部材とを接続するときに、各接続面の表面粗さを所定の範囲とし、所定のエネルギー密度のレーザーを使用して各電極板と集電部材とを溶着することにより、生産性に優れたリチウム二次電池の製造方法を提供することにある。
【００１０】
【課題を解決するための手段】上記目的を達成するために、本発明によって以下のリチウム二次電池の製造方法が提供される。
【００１１】
［１］ 少なくとも１枚の金属箔体からそれぞれ構成された正極板及び負極板をセパレータを介して捲回又は積層して捲回型内部電極体又は積層型内部電極体を形成し、前記正極板及び負極板の端部を、それらの端部から電流を導出するために、アルミニウム又はアルミニウム合金からなる正極集電部材、及び銅又は銅合金からなる負極集電部材のそれぞれの所定箇所（接続部）にそれぞれ接続するリチウム二次電池の製造方法であって、前記正極集電部材の接続部の表面（接続面）の表面粗さを中心線平均表面粗さＲａで０．０５〜６．３μｍＲａとし、前記正極集電部材の接続部をパワー密度が５ｋＷ／ｍｍ２以上のレーザーで溶融して、前記正極集電部材の接続部を前記正極板の端部に溶着することにより、前記正極板の端部を前記正極集電部材の接続部に接続することを特徴とするリチウム二次電池の製造方法（第１の発明ということがある）。
【００１２】
［２］ 前記正極集電部材及び前記負極集電部材のうちの少なくとも一方から電流を導出するための内部端子を、前記正極集電部材及び前記負極集電部材のうちの少なくとも一方に電極リード部材を用いて接続する［１］に記載のリチウム二次電池の製造方法。
【００１３】
［３］ 前記正極集電部材及び前記負極集電部材のうちの少なくとも一方に、直接電池外部に電流を導出するように外部端子を配設する［１］に記載のリチウム二次電池の製造方法。
【００１４】
［４］ 前記正極集電部材の接続部を、前記正極集電部材の前記正極板に向かって列状に連続して突出した凸状とし、凸状の前記接続部の先端部分に前記接続面を形成し、前記接続面と前記正極板の端部の狭幅端面とを対向させた状態で接続する［１］〜［３］のいずれかに記載のリチウム二次電池の製造方法。
【００１５】
［５］ 前記正極集電部材の前記凸状の接続部に前記レーザーを照射して、前記凸状の接続部を溶融することにより、前記凸状の接続部を前記正極板の端部に溶着する［４］に記載のリチウム二次電池の製造方法。
【００１６】
［６］ 前記正極集電部材及び前記負極集電部材のうちの少なくとも一方を、十字形、Ｙ字形、若しくはＩ字形の板状部材、又は一部に切り欠きを有する円板状部材とする［１］〜［５］のいずれかに記載のリチウム二次電池の製造方法。
【００１７】
［７］ 前記正極集電部材を、前記凸状の接続部とそれ以外の平坦部とを有する形状とし、前記凸状の接続部の厚み（Ｌ２）と、前記平坦部の厚み（Ｌ１）との差を０．１ｍｍ以上とする［４］〜［６］のいずれかに記載のリチウム二次電池の製造方法。
【００１８】
［８］ 前記正極集電部材の前記平坦部の厚み（Ｌ１）を０．４ｍｍ以上とする［７］に記載のリチウム二次電池の製造方法。
【００１９】
［９］ 前記正極集電部材における前記凸状の接続部の厚み（Ｌ２）を０．６ｍｍ以上とする［７］又は［８］に記載のリチウム二次電池の製造方法。
【００２０】
［１０］ 前記正極集電部材の前記凸状の接続部に、前記レーザーを照射して前記凸状の接続部を溶融するときに、前記正極板の端部の前記狭幅端面を含む面の法線に対して、角度θ（０＜θ≦９０°）で前記レーザーを照射する［５］〜［９］のいずれかに記載のリチウム二次電池の製造方法。
【００２１】
［１１］ 前記レーザーが照射される範囲（照射点）の径を１ｍｍ以下とする［５］〜［１０］のいずれかに記載のリチウム二次電池の製造方法。
【００２２】
［１２］ 前記正極集電部材の前記接続部と前記正極板の端部との接続を補助する接続材を、前記正極板の端部及び前記正極集電部材の前記接続部のうちの少なくとも一方に塗布し、又は前記正極板の端部と前記正極集電部材の前記接続部との間に挟時させて、前記正極集電部材の前記接続部及び前記接続材に前記レーザーを照射し、前記正極集電部材の前記接続部及び前記接続材を溶融させて、溶融した前記正極集電部材の前記接続部及び前記接続材を、前記正極板の端部に溶着させる［１］〜［１１］のいずれかに記載のリチウム二次電池の製造方法。
【００２３】
［１３］ 前記負極集電部材の接続部の表面（接続面）の表面粗さを中心線平均表面粗さＲａで０．０５〜６．３μｍＲａとし、前記負極集電部材の接続部をパワー密度が３ｋＷ／ｍｍ２以上のレーザーで溶融して、前記負極集電部材の接続部を前記負極板の端部に溶着することにより、前記負極板の端部を前記負極集電部材の接続部に接続する［１］〜［１２］のいずれかに記載のリチウム二次電池の製造方法（第２の発明ということがある）。
【００２４】
［１４］ 前記負極集電部材の接続部を、前記負極集電部材の前記負極板に向かって列状に連続して突出した凸状とし、凸状の前記接続部の先端部分に前記接続面を形成し、前記負極板の端部近傍を屈曲させて前記負極板の端部近傍の側面部が前記負極集電部材の前記接続面に対向するようにし、前記負極板の端部近傍の側面部と前記負極集電部材の前記接続面とを接続する［１３］に記載のリチウム二次電池の製造方法。
【００２５】
［１５］ 前記負極板の端部近傍の側面部と前記負極集電部材の前記接続面とを接続するときに、前記負極板の端部近傍の側面部から前記負極集電部材の方向へ柱状晶が形成されるようにする［１４］に記載のリチウム二次電池の製造方法。
【００２６】
［１６］ 前記負極集電部材の前記凸状の接続部に前記レーザーを照射して、前記凸状の接続部を溶融することにより、前記凸状の接続部を前記負極板の端部に溶着する［１４］又は［１５］に記載のリチウム二次電池の製造方法。
【００２７】
［１７］ 前記正極集電部材及び前記負極集電部材のうちの少なくとも一方を、前記凸状の接続部とそれ以外の平坦部とを有する形状とし、前記凸状の接続部の厚み（Ｌ２）と、前記平坦部の厚み（Ｌ１）との差を０．１ｍｍ以上とする［１４］〜［１６］のいずれかに記載のリチウム二次電池の製造方法。
【００２８】
［１８］ 前記負極集電部材の前記平坦部の厚み（Ｌ１）を０．２ｍｍ以上とする［１７］に記載のリチウム二次電池の製造方法。
【００２９】
［１９］ 前記負極集電部材の前記凸状の接続部の厚み（Ｌ２）が０．４ｍｍ以上である［１７］又は［１８］に記載のリチウム二次電池の製造方法。
【００３０】
［２０］ 前記負極集電部材の前記凸状の接続部に前記レーザーを照射して前記凸状の接続部を溶融するときに、前記負極集電部材の前記接続面に対向するように形成した前記負極板の端部近傍の側面部を含む面の法線に対して、角度θ（０≦θ≦３０°）で前記レーザーを照射する［１６］〜［１９］のいずれかに記載のリチウム二次電池の製造方法。
【００３１】
［２１］ 前記負極集電部材の前記凸状の接続部に前記レーザーを照射して前記凸状の接続部を溶融するときに、前記凸状の接続部の厚みをＬ２（ｍｍ）、前記レーザーの前記パワー密度をＥ（ｋＷ／ｍｍ２）としたときに、下記式（３）を満足する［１６］〜［２０］のいずれかに記載のリチウム二次電池の製造方法。
【００３２】
【数３】
Ｌ２≦Ｅ／７ …（３）
【００３３】
［２２］ 前記レーザーが照射される範囲（照射点）の径を１ｍｍ以下とする［１６］〜［２１］のいずれかに記載のリチウム二次電池の製造方法。
【００３４】
［２３］ 前記負極集電部材の前記接続部と前記負極板の端部との接続を補助する接続材を、前記負極板の端部及び前記負極集電部材の前記接続部のうちの少なくとも一方に塗布し、又は前記負極板の端部と前記負極集電部材の前記接続部との間に挟時させて、前記負極集電部材の前記接続部及び前記接続材に前記レーザーを照射し、前記負極集電部材の前記接続部及び前記接続材を溶融させて、溶融した前記負極集電部材の前記接続部及び前記接続材を、前記負極板の端部に溶着させる［１３］〜［２２］のいずれかに記載のリチウム二次電池の製造方法。
【００３５】
［２４］ 少なくとも１枚の金属箔体からそれぞれ構成された正極板及び負極板をセパレータを介して捲回又は積層して捲回型内部電極体又は積層型内部電極体を形成し、前記正極板及び負極板の端部を、それらの端部から電流を導出するために、アルミニウム又はアルミニウム合金からなる正極集電部材、及び銅又は銅合金からなる負極集電部材のそれぞれの所定箇所（接続部）にそれぞれ接続するリチウム二次電池の製造方法であって、前記負極集電部材の接続部の表面（接続面）の表面粗さを中心線平均表面粗さＲａで０．０５〜６．３μｍＲａとし、前記負極集電部材の接続部をパワー密度が３ｋＷ／ｍｍ２以上のレーザーで溶融して、前記負極集電部材の接続部を前記負極板の端部に溶着することにより、前記負極板の端部を前記負極集電部材の接続部に接続することを特徴とするリチウム二次電池の製造方法。
【００３６】
［２５］ 前記正極集電部材及び前記負極集電部材のうちの少なくとも一方から電流を導出するための内部端子を、前記正極集電部材及び前記負極集電部材のうちの少なくとも一方に電極リード部材を用いて接続する［２４］に記載のリチウム二次電池の製造方法。
【００３７】
［２６］ 前記正極集電部材及び前記負極集電部材のうちの少なくとも一方に、直接電池外部に電流を導出するように外部端子を配設する［２４］に記載のリチウム二次電池の製造方法。
【００３８】
［２７］ 前記負極集電部材の接続部を、前記負極集電部材の前記負極板に向かって列状に連続して突出した凸状とし、凸状の前記接続部の先端部分に前記接続面を形成し、前記負極板の端部近傍を屈曲させて前記負極板の端部近傍の側面部が前記負極集電部材の前記接続面に対向するようにし、前記負極板の端部近傍の側面部と前記負極集電部材の前記接続面とを接続する［２４］〜［２６］のいずれかに記載のリチウム二次電池の製造方法。
【００３９】
［２８］ 前記負極板の端部近傍の側面部と前記負極集電部材の前記接続面とを接続するときに、前記負極板の端部近傍の側面部から前記負極集電部材の方向へ柱状晶が形成されるようにする［２７］に記載のリチウム二次電池の製造方法。
【００４０】
［２９］ 前記負極集電部材の前記凸状の接続部に前記レーザーを照射して、前記凸状の接続部を溶融することにより、前記凸状の接続部を前記負極板の端部に溶着する［２７］又は［２８］に記載のリチウム二次電池の製造方法。
【００４１】
［３０］ 前記正極集電部材及び前記負極集電部材のうちの少なくとも一方を、十字形、Ｙ字形、若しくはＩ字形の板状部材、又は一部に切り欠きを有する円板状部材とする［２４］〜［２９］のいずれかに記載のリチウム二次電池の製造方法。
【００４２】
［３１］ 前記負極集電部材を、前記凸状の接続部とそれ以外の平坦部とを有する形状とし、前記凸状の接続部の厚み（Ｌ２）と、前記平坦部の厚み（Ｌ１）との差を０．１ｍｍ以上とする［２７］〜［３０］のいずれかに記載のリチウム二次電池の製造方法。
【００４３】
［３２］ 前記負極集電部材の前記平坦部の厚み（Ｌ１）を０．２ｍｍ以上とする［３１］に記載のリチウム二次電池の製造方法。
【００４４】
［３３］ 前記負極集電部材の前記凸状の接続部の厚み（Ｌ２）が０．４ｍｍ以上である［３１］又は［３２］に記載のリチウム二次電池の製造方法。
【００４５】
［３４］ 前記負極集電部材の前記凸状の接続部に前記レーザーを照射して前記凸状の接続部を溶融するときに、前記負極集電部材の前記接続面に対向するように形成した前記負極板の端部近傍の側面部を含む面の法線に対して、角度θ（０≦θ≦３０°）で前記レーザーを照射する［２９］〜［３３］のいずれかに記載のリチウム二次電池の製造方法。
【００４６】
［３５］ 前記負極集電部材の前記凸状の接続部に前記レーザーを照射して前記凸状の接続部を溶融するときに、前記凸状の接続部の厚みをＬ２（ｍｍ）、前記レーザーの前記パワー密度をＥ（ｋＷ／ｍｍ２）としたときに、下記式（４）を満足する［２９］〜［３４］のいずれかに記載のリチウム二次電池の製造方法。
【００４７】
【数４】
Ｌ２≦Ｅ／７ …（４）
【００４８】
［３６］ 前記レーザーが照射される範囲（照射点）の径を１ｍｍ以下とする［２９］〜［３５］のいずれかに記載のリチウム二次電池の製造方法。
【００４９】
［３７］ 前記負極集電部材の前記接続部と前記負極板の端部との接続を補助する接続材を、前記負極板の端部及び前記負極集電部材の前記接続部のうちの少なくとも一方に塗布し、又は前記負極板の端部と前記負極集電部材の前記接続部との間に挟時させて、前記負極集電部材の前記接続部及び前記接続材に前記レーザーを照射し、前記負極集電部材の前記接続部及び前記接続材を溶融させて、溶融した前記負極集電部材の前記接続部及び前記接続材を、前記負極板の端部に溶着させる［２４］〜［３６］のいずれかに記載のリチウム二次電池の製造方法。
【００５０】
［３８］ 前記レーザーが連続波である［１］〜［３７］のいずれかに記載のリチウム二次電池の製造方法。
【００５１】
［３９］ 前記レーザーがＹＡＧレーザーである［１］〜［３８］のいずれかに記載のリチウム二次電池の製造方法。
【００５２】
［４０］ 前記リチウム二次電池の電池容量が２Ａｈ以上である［１］〜［３９］のいずれかに記載のリチウム二次電池の製造方法。
【００５３】
［４１］ 前記リチウム二次電池が車載用電池である［１］〜［４０］のいずれかに記載のリチウム二次電池の製造方法。
【００５４】
［４２］ 前記リチウム二次電池が電気自動車用又はハイブリッド電気自動車用電池である［４１］に記載のリチウム二次電池の製造方法。
【００５５】
［４３］ 前記リチウム二次電池がエンジン起動用電池である［４１］又は［４２］に記載のリチウム二次電池の製造方法。
【００５６】このように、各電極板の端部と集電部材を直接的に接続して内部電極体から電流を導出するという構成を採用し、正極板と正極集電部材とを接続するときに、接続面の表面粗さを所定の範囲とし、所定のエネルギー密度のレーザーを使用して正極板と正極集電部材とを溶着するようにしたため（第１の発明）、生産性に優れたリチウム二次電池の製造方法を提供することができる。また、各電極板の端部と集電部材を直接的に接続して内部電極体から電流を導出するという構成を採用し、負極板と負極集電部材とを接続するときに、接続面の表面粗さを所定の範囲とし、所定のエネルギー密度のレーザーを使用して負極板と負極集電部材とを溶着するようにしたため（第２の発明）、生産性に優れたリチウム二次電池の製造方法を提供することができる。
【００５７】
【発明の実施の形態】以下、本発明（第１の発明及び第２の発明）の実施の形態を図面を参照しながら具体的に説明するが、本発明は以下の実施の形態に限定されるものではなく、本発明の趣旨を逸脱しない範囲で、当業者の通常の知識に基づいて、適宜設計の変更、改良等が加えられることが理解されるべきである。
【００５８】第１の発明のリチウム二次電池の製造方法は、少なくとも１枚の金属箔体からそれぞれ構成された正極板及び負極板をセパレータを介して捲回して捲回型内部電極体を形成し、正極板及び負極板のそれぞれの端部を、それらの端部から電流を導出するために、アルミニウムからなる正極集電部材、及び銅からなる負極集電部材のそれぞれの所定箇所（接続部）にそれぞれ接続してリチウム二次電池を製造するものであって、正極板の端部を正極集電部材の接続部に接続するときに、正極集電部材の接続部をパワー密度が５ｋＷ／ｍｍ２以上のレーザーで溶融して、その正極集電部材の接続部を正極板の端部に溶着し、更に、正極集電部材の接続部の表面（接続面）の表面粗さを中心線平均表面粗さＲａで０．０５〜６．３μｍＲａとするものである。また、第２の発明のリチウム二次電池の製造方法は、少なくとも１枚の金属箔体からそれぞれ構成された正極板及び負極板をセパレータを介して捲回して捲回型内部電極体を形成し、正極板及び負極板のそれぞれの端部を、それらの端部から電流を導出するために、アルミニウムからなる正極集電部材、及び銅からなる負極集電部材のそれぞれの所定箇所（接続部）にそれぞれ接続してリチウム二次電池を製造するものであって、負極板の端部を負極集電部材の接続部に接続するときに、負極集電部材の接続部をパワー密度が３ｋＷ／ｍｍ２以上のレーザーで溶融して、その負極集電部材の接続部を負極板の端部に溶着し、更に、負極集電部材の接続部の表面（接続面）の表面粗さを中心線平均表面粗さＲａで０．０５〜６．３μｍＲａとするものである。そして、第１の発明と第２の発明のそれぞれの要件を同時に満たすことが好ましい。
【００５９】ここで、本発明にいうレーザーの「パワー密度」とは、レーザーのパワー（ｋＷ）を、正極又は負極集電部材の所定箇所（接続部）において当該レーザーが照射される照射点のスポット面積（ｍｍ２）で除して得た値を意味する。また、捲回型内部電極体は、少なくとも１枚の金属箔体からそれぞれ構成された正極板及び負極板をセパレータを介して積層して形成する積層型内部電極体であってもよい。更に、正極集電部材はアルミニウム合金から形成されてもよいし、負極集電部材は銅合金から形成されてもよい。また、中心線平均表面粗さＲａとは、ＪＩＳ Ｂ ０６０１及び、ＩＳＯ Ｒ １１０１で規定している表面粗さである。
【００６０】正極集電部材の接続部と正極板、及び負極集電部材の接続部と負極板を、それぞれ接続するときに、接続部に広範囲（例えば接続部からはみ出すぐらいに広い範囲）に渡って強いエネルギー線を照射すると、正極板を構成する正極金属箔体や負極板を構成する負極金属箔体を損傷して歩留まりが悪化し、また、損傷しない場合でも、仕上がり状態の悪いものとなるため、弱いエネルギーで必要な位置に集中的にエネルギー線等を照射する必要がある。しかし、エネルギーが弱過ぎると溶融させるべき箇所が溶融しないため、ある程度以上のエネルギーは必要になる。そこで、第１の発明では、エネルギー線をレーザーとし、正極集電部材をアルミニウムとして、そのアルミニウムを溶融して正極集電部材（の接続部）と正極板とを溶着させるためのレーザーのエネルギー密度を５ｋＷ／ｍｍ２以上としたため、また、第２の発明では、負極集電部材を銅として、その銅を溶融して負極集電部材（の接続部）と負極板とを溶着させるためのレーザーのエネルギー密度を３ｋＷ／ｍｍ２以上としたため、正極集電部材又は負極集電部材を確実に溶融させることができ、更に、これらレーザーのエネルギー密度の下限値を基準としてレーザーのエネルギー密度を最適化することができるため、弱いエネルギー密度で効果的に正極集電部材又は負極集電部材を溶融することができる。これにより、正極金属箔体又は負極金属箔体の損傷等が発生することなく、生産性に優れたリチウム二次電池の製造方法を得ることができる。また、第１の発明及び第２の発明のそれぞれの要件を同時に満たす場合には、正極集電部材及び負極集電部材の双方を確実に溶融させることができ、弱いエネルギー密度で効果的に正極集電部材及び負極集電部材の双方を溶融することができる。
【００６１】正極集電部材（の接続部）と正極板とを溶着させるためのレーザーのエネルギー密度が５ｋＷ／ｍｍ２より小さいとき（第１の発明の要件を満たさないとき）、及び負極集電部材（の接続部）と負極板とを溶着させるためのレーザーのエネルギー密度が３ｋＷ／ｍｍ２より小さいとき（第２の発明の要件を満たさないとき）には、接続状態が良好ではなく、機械的強度が不充分となる。
【００６２】正極集電部材（の接続部）と正極板とをレーザーで接続（溶着）する場合（第１の発明）、及び負極集電部材（の接続部）と負極板とをレーザーで接続（溶着）する場合（第２の発明）には、その接続面の表面粗さが影響するが、中心線平均表面粗さＲａで０．０５〜６．３μｍＲａとすることにより、レーザーによる接続を良好に行うことができる。
【００６３】以下に、第１の発明のリチウム二次電池の製造方法の一の実施の形態について説明する。図１は、第１の発明のリチウム二次電池の製造方法の、一の実施の形態における、正極板と正極集電部材とを接続する方法を模式的に示す斜視図である。図１に示すように、本実施の形態のリチウム二次電池の製造方法では、正極集電部材４Ａと正極板１Ａとの接続は、少なくとも１枚の金属箔体から構成される正極板１Ａの端部１５の狭幅端面２と、正極集電部材４Ａの接続部５の接続面９とを、所定の位置に配置し、所定のパワー密度のレーザー１１で接続部５を溶融して、接続部５と正極板の端部１５とを溶着することにより行う。このとき狭幅端面２上の複数箇所と接続面９とが溶着される。
【００６４】図２は、本実施の形態のリチウム二次電池の製造方法における、負極板と負極集電部材とを接続する方法の一実施例を模式的に示す斜視図である。図２に示すように、本実施の形態のリチウム二次電池の製造方法では、負極集電部材４Ｂと負極板１Ｂとの接続は、少なくとも１枚の金属箔体から構成される負極板１Ｂの端部１５の近傍を屈曲させて負極集電部材４Ｂの接続部５側（接続面９側）を向けた側面部１３と、負極集電部材４Ｂの接続部５の接続面９と、を所定の位置に配置し、所定のパワー密度のレーザー１１で接続部５を溶融して、接続部５と負極板の端部１５とを溶着することにより行うことが好ましい。このとき側面部１３上の複数箇所と接続面９とが溶着される。
【００６５】本実施の形態のリチウム二次電池の製造方法においては、図３に示すように、前記構成に加えて内部端子６９Ａ，６９Ｂ、外部端子７０Ａ，７０Ｂ、及び電池蓋７１Ａ，７１Ｂを有する電極蓋を作製し、上述の方法により捲回型内部電極体６１の正極板１Ａ（図１参照）に正極集電部材４Ａを接続し負極板１Ｂ（図２参照）に負極集電部材４Ｂを接続したものの、正極集電部材４Ａ及び負極集電部材４Ｂを、内部端子６９Ａ及び６９Ｂに各々電極リード部材７２を用いて接続する。このとき、電極リード部材７２としては、接続される集電部材４Ａ，４Ｂ及び内部端子６９Ａ，６９Ｂと、その合金を含む同種金属から構成されることが好ましい。具体的には、正極内部端子６９Ａ及び正極集電部材４Ａにはアルミニウム又はアルミニウム合金を用いているので、正極の電極リード部材にアルミニウム又はアルミニウム合金を採用し、負極内部端子６９Ｂ及び負極集電部材４Ｂには銅又は銅合金を用いているので、負極の電極リード部材に銅又は銅合金を採用することが好ましい。
【００６６】そして、本実施の形態のリチウム二次電池の製造方法では、上述の電極蓋を配設した捲回型内部電極体６１を電池ケース７３に挿入し、電池ケース７３の両端部近傍をくびれ加工して、くびれ加工部を形成し、電解液を注入することによりリチウム二次電池６８を得ることができる。図３において、符号６７は巻芯、符号７５は放圧弁である。
【００６７】なお、本実施の形態では、電極リード部材７２を用いなくとも、集電部材４Ａ，４Ｂと内部端子６９Ａ，６９Ｂとを直接的に接続し、通電させてもよい。また、上述のような電流導出部分としての電極蓋を、正極及び負極に用いてもよいし、正極又は負極のどちらか一方で用いてもよい。
【００６８】また、本発明（第１の発明）においては、図６に示すように、集電部材５４に直接外部端子を配設し、電池外部に直接電流を導出するように形成して、集電部材５４を電極蓋と兼用するようにしてもよい。図６では、片端が開放された円筒形の電池ケース７３を用い、その電池ケース７３の片端にくびれ加工を形成した例を示しているが、集電部材５４が電極蓋を兼用していれば、リチウム二次電池６８の形状に特に制限はなく、電池ケース７３の両端をくびれ加工しても、或いは電池ケース７３の両端をくびれ加工しなくてもよい。また、図６では、正極側に放圧孔７５を形成する例を示しているが、負極側に放圧孔を形成してもよい。図６において、符号６１は捲回型内部電極体、符号６７は巻芯を示す。
【００６９】図３，６に示すように、内部電極体（捲回型内部電極体６１）からの電流導出部分に、各電極板と集電部材４Ａ，４Ｂ（図３参照），５４（図６参照）を直接的に接続して電流を導出するという構成を採用することにより、従来の電流導出手段である集電タブを用いる必要がないために、煩雑な集電タブの取り付け工程を不要とすることにより、生産性の向上を図ることが出来、また、集電タブの長さの分のスペースを省くことが出来ることより、省スペース性の向上を図ることが出来る。
【００７０】本実施の形態においては、図７に示すように、正極集電部材４Ａの接続部５を、正極集電部材４Ａの正極板１Ａ側を向く面４Ｃから正極板１Ａに向かって列状に連続して突出した凸状（突条）とし、凸状の接続部５の先端部分に接続面９を形成し、接続面９と正極板１Ａの端部１５の狭幅端面２とを対向させた状態で接続することが好ましい。そして、図７に示すように、正極板１Ａの端部１５と、正極集電部材４Ａの接続部５とを接続するときには、凸状の接続部５にレーザー１１を照射し、凸状の接続部５を溶融して、正極集電部材４Ａの凸状の接続部５と正極板１Ａの端部１５とを溶着させることが好ましい。さらに、正極集電部材４Ａにおいて接続部５が配設される位置は、正極集電部材４Ａの先端部６であることが、接続面の確認をし易いことから好ましい。図７において、１２は平坦部を示し、正極集電部材４Ａは接続部５と平坦部１２とを有する構造となっている。また、凸状の接続部としては、図１に示すように、正極集電部材４Ａの正極板１Ａ側を向く面４Ｃから正極板１Ａに向かって凸状に突出し、且つ正極集電部材４Ａを外側に延長する方向に延設するように形成した形状も含まれる。
【００７１】また、図７に示す、正極集電部材４Ａの凸状の接続部５の凸状の形状は特に制限はなく、正極板１Ａの端部１５と正極集電部材４Ａとの溶着を容易にするために、凸状の接続部５の接続面９と正極金属箔体１Ａの狭幅端面２との接触を確実に行うことが好ましく、例えば、上述の図１に示す接続部５のような形状にしてもよいし、また凸状の接続部５の接続面９と正極金属箔体１Ａの狭幅端面２とが点接触するように形成することを好適例として挙げることが出来る。
【００７２】正極集電部材４Ａ及び負極集電部材４Ｂの凸状の接続部５の形状の具体的な例を図１４，１５に示す。本発明のリチウム二次電池に用いられる正極集電部材４Ａ及び後述する負極集電部材４Ｂのそれぞれの凸状の接続部５の形状は、図１４に示すような台形状であってもよく、図１５に示すような尖塔状であってもよい。なお、図１４，１５においてＬ１は平坦部１２の厚み、Ｌ２は凸状の接続部５の厚みを示す。
【００７３】本実施の形態のリチウム二次電池の製造方法においては、図１４，１５に示すように、正極集電部材４Ａを凸状の接続部５とそれ以外の平坦部１２とを有する形状とし、凸状の接続部５の厚み（Ｌ２）と、平坦部１２の厚み（Ｌ１）との差を０．１ｍｍ以上とすることが好ましく、０．６ｍｍ以上とすることがさらに好ましく、０．８ｍｍ以上とすることが特に好ましい。凸状の接続部５と平坦部１２との厚みの差が０．１ｍｍ未満である場合には、凸状の接続部５の形状的な特徴が発揮されず、凸状の接続部５と正極板１Ａとの接触状態が不安定となるために好ましくない。また、本発明においては凸状の接続部５と平坦部１２との厚みの差の上限値については特に限定されないが、正極集電部材の加工精度及び強度等から適宜設定されればよく、例えば３ｍｍ以下であればよい。
【００７４】また、接続に際して正極板に正極集電部材を押さえ付けるときに、当該正極集電部材の変形や損傷等の発生を防止するといった観点からは、正極集電部材４Ａの平坦部の厚み（Ｌ１）を０．４ｍｍ以上とすることが好ましく、０．５ｍｍ以上とすることがさらに好ましく、０．６ｍｍ以上とすることが特に好ましい。なお、前記平坦部の厚みの上限値については特に限定されないが、溶接部分とは直接的には関係のない部分であるため正極集電部材の強度及び重量等から適宜設定されればよく、例えば２ｍｍ以下であればよい。
【００７５】また、正極集電部材４Ａの凸状の接続部５の厚み（Ｌ２）を０．６ｍｍ以上とすることが好ましく、０．７ｍｍ以上とすることがさらに好ましく、０．８ｍｍ以上とすることが特に好ましい。このことにより、より強固に接続することが出来る。なお、凸状の接続部５の厚みの上限値については特に限定されないが、照射されるレーザーのパワーの限界から適宜設定されればよい。
【００７６】本発明のリチウム二次電池に用いられる正極集電部材のレーザー照射部の形状に関して、以下に示す形状のものを好適な例として挙げることが出来る。
【００７７】図７には、先端部６に凸状の接続部５を有する正極集電部材４Ａを使用する例を示しているが、この場合には、正極集電部材４Ａの上面側（面４Ｃの反対側）からレーザー１１を照射することにより、正極集電部材４Ａと正極板１Ａの端部１５とを溶着させて接続させることが出来る。
【００７８】図９には、図７の正極集電部材４Ａに比べ、凸状の接続部３３に厚みを有する正極集電部材３１Ａを使用する例を示しているが、この場合には、正極集電部材３１Ａの上面側からレーザー３４を照射することの他に、正極集電部材３１Ａの先端部３２に形成された凸状の接続部３３の側面へレーザー３５を照射することによっても、正極集電部材３１Ａと正極板１Ａの端部１５とを溶着させて接続させることが出来る。図９において、２は狭幅端面、３Ａは狭幅端面を含む面の法線を示す。
【００７９】図１０には、板状の正極集電部材４１を、その端面が正極板１Ａの端部１５に接するように配置する例を示しているが、この場合には、正極集電部材４１の側面側からレーザー４２を照射することにより、正極集電部材４１と正極板１Ａの端部１５とを溶着させて接続させることが出来る。このように、本発明のリチウム二次電池は、図１０に示すような、凸状部を有しない板状の正極集電部材４１と複数の正極板１Ａとを接続させることによっても製造することが出来る。図１０において、２は狭幅端面、３Ａは狭幅端面を含む面の法線を示す。
【００８０】図１１には、正極集電部材５１Ａの先端部ではない、所定箇所に凸状の接続部５２を有する例を示しているが、この場合には、その凸状の接続部５２を設けた正極集電部材５１Ａの背面にレーザー５３を照射して、その正極集電部材５１Ａと正極板１Ａの端部１５とを接続させることが出来る。図１１において、２は狭幅端面を示す。
【００８１】一方、本実施の形態においては、図８に示すように、負極集電部材４Ｂの接続部５を、負極集電部材４Ｂの負極板１Ｂ側を向く面４Ｄから負極板１Ｂに向かって列状に連続して突出した凸状とし、凸状の接続部５の先端部分に接続面９を形成し、負極板１Ｂの端部１５近傍を屈曲させて負極板１Ｂの端部１５近傍の側面部１３が負極集電部材４Ｂの接続面９に対向するようにし、負極板１Ｂの端部１５近傍の側面部１３と負極集電部材４Ｂの接続面９（接続部５）とを接続することが好ましい。そして、図８に示すように、負極板１Ｂの端部１５と、負極集電部材４Ｂの凸状の接続部５とを接続するときには、凸状の接続部５にレーザー１１を照射し、凸状の接続部５を溶融して、負極集電部材４Ｂの凸状の接続部５と負極板１Ｂの端部１５とを溶着させることが好ましい。さらに、負極集電部材４Ｂにおいて、接続部５が配設される位置は、負極集電部材４Ｂの先端部６であることが、接続面の確認のし易いことから好ましい。図８において、１２は平坦部、Ｌ１は平坦部１２の厚み、Ｌ２は接続部５の厚みを示す。負極集電部材４Ｂは接続部５と平坦部１２とを有する構造となっている。また、凸状の接続部としては、図２に示すように、負極集電部材４Ｂの負極板１Ｂ側を向く面４Ｃから負極板１Ｂに向かって凸状に突出し、且つ負極集電部材４Ｂを外側に延長する方向に延設するように形成した形状も含まれる。
【００８２】本実施の形態においては、図８に示すように、負極板１Ｂと負極集電部材４Ｂとを接続するときには、端部１５近傍を屈曲することにより側面部１３と、凸状の接続部５の接続面９とを密着させればよいが、このように側面部１３と接続面９とを密着させる方法としては、例えば、図１６に示すように、予め適当な方法により負極板１Ｂの端部１５近傍を屈曲しておき（図１６（ａ））、次いで、側面部１３の上に負極集電部材４Ｂを配置する（図１６（ｂ））方法がある。また、図１７に示すように、負極板１Ｂの端部１５に負極集電部材４Ｂを適当な圧力で押さえ付けて、端部１５近傍を屈曲し側面部１３を密着させる方法（図１７（ａ），（ｂ），（ｃ））を挙げることも出来る。
【００８３】本実施の形態のリチウム二次電池の製造方法においては、負極板の端部近傍の側面部と負極集電部材の接続面とを接続するときに、負極板の端部近傍の側面部から負極集電部材の方向へ柱状晶が形成されるようにすることが好ましい。一般に溶接金属は、溶融金属が母材（未溶融部）の結晶粒上に同一結晶方位をもって成長（エピタキシャル成長）する。このように形成された固相は熱源の移動に伴い、溶接ビード（溶融部分）内部へ成長する。この成長は、温度勾配の最も大きい方向に成長し易く、その方向へほぼ一方向にのびた形態で成長し、このように成長した結晶は柱状晶と呼ばれる。
【００８４】負極集電部材の溶融化した部分は、冷却されるにしたがって再結晶化するが、負極板１Ｂを通じて溶融部分の熱が急速に拡散する。すなわち、負極板に密着した部分の溶融金属の温度が低下し、負極板と溶融金属の界面が核となって負極板から負極集電部材の方向へ柱状晶が形成し易くなると考えられる。さらに、本実施の形態では負極板の端部近傍の側面部が負極集電部材と隙間なく密着して接触状態が良好であるために、負極板を通じた冷却効果により、柱状晶が形成し易い状態となる。このように、負極板と負極集電部材との接続部分において、負極板から負極集電部材の方向へ柱状晶を形成することにより、負極板と負極集電部材との接続状態が良好、すなわち、接続部分の機械的強度が強く信頼性に優れたリチウム二次電池を得ることができる。
【００８５】本実施の形態のリチウム二次電池の製造方法に用いられる負極集電部材の凸状の接続部の形状には特に制限はない。ここで、凸状の接続部の形状の具体的な例を図１４，１５に示す。本実施の形態のリチウム二次電池の製造方法に用いられる負極集電部材４Ｂの凸状の接続部５の形状は、上述したように、図１４に示すような台形状であってもよく、図１５に示すような尖塔状であってもよい。
【００８６】本実施の形態のリチウム二次電池においては、図１４，１５に示すように負極集電部材４Ｂは凸状の接続部５とそれ以外の平坦部１２とを有する形状であり、凸状の接続部５の厚み（Ｌ２）と、平坦部１２の厚み（Ｌ１）との差を０．１ｍｍ以上とすることが好ましく、０．６ｍｍ以上とすることがさらに好ましく、０．８ｍｍ以上とすることが特に好ましい。凸状の接続部５と平坦部１２との厚みの差が０．１ｍｍ未満である場合には、凸状の接続部５の形状的な特徴が発揮されず、凸状の接続部５と負極板１Ｂとの接触状態が不安定となるために好ましくない。また、負極集電部材４Ｂの凸状の接続部５と平坦部１２との厚みの差の上限値については特に限定されないが、負極集電部材の加工精度及び強度等から適宜設定されればよく、例えば３ｍｍ以下であればよい。
【００８７】接続に際して負極板に負極集電部材を押さえ付けるときに、負極集電部材の変形や損傷等の発生を防止するといった観点からは、平坦部の厚み（Ｌ１）を０．２ｍｍ以上とすることが好ましく、０．３ｍｍ以上とすることがさらに好ましく、０．４ｍｍ以上とすることが特に好ましい。なお、平坦部の厚みの上限値については特に限定されないが、溶接部分とは直接的には関係のない部分であるため負極集電部材の強度及び重量等から適宜設定されればよく、例えば２ｍｍ以下であればよい。
【００８８】また、負極集電部材４Ｂの凸状の接続部の厚み（Ｌ２）を０．４ｍｍ以上とすることが好ましく、０．５ｍｍ以上とすることがさらに好ましく、０．６ｍｍ以上とすることが特に好ましい。このことにより、より強固に接続することが出来る。なお、凸状の接続部の厚みの上限値については特に限定されないが、照射されるレーザーのパワーの限界から適宜設定されればよい。
【００８９】本実施の形態のリチウム二次電池に用いられる負極集電部材のレーザー照射部（接続部）の形状に関して、以下に示す形状のものを好適な例として挙げることが出来る。
【００９０】図８には、先端部６に凸状の接続部５を有する負極集電部材４Ｂの例を示しているが、この場合には、負極集電部材４Ｂの上面側からレーザー１１を照射することにより、負極集電部材４Ｂと負極板１Ｂの端部１５とを溶着させて接続させることが出来る。
【００９１】図１２には、図８の負極集電部材４Ｂに比べ、先端部３２に形成された凸状の接続部３３に厚みを有する負極集電部材３１Ｂの例を示しているが、この場合には、負極集電部材３１Ｂの上面側からレーザー３４を照射することによって、負極集電部材３１Ｂと負極板１Ｂの端部１５（側面部１３）とを溶着させて接続させることが出来る。３Ｂは側面部１３を含む面の法線を示す。
【００９２】図１３には、負極集電部材５１Ｂの先端部ではない、所定箇所に凸状の接続部５２を有する例を示しているが、この場合には、その凸状の接続部５２を設けた負極集電部材５１Ｂの背面にレーザー５３を照射して、その負極集電部材５１Ｂと負極板１Ｂの端部１５近傍の側面部１３とを接続させることが出来る。図１３において、１２は平坦部を示す。
【００９３】本実施の形態において、正極板に正極集電部材と同じ材質のアルミニウム又はアルミニウム合金を使用し、負極板に負極集電部材と同じ材質の銅又は銅合金を使用した場合には、金属板（金属箔体）と集電部材とが同種金属から構成されることとなるために、金属板（金属箔体）と集電部材とがよりよく溶着され、電流導出部分の機械的強度を強くすることが出来る。この場合、アルミニウム又はアルミニウム合金から構成される正極板（金属箔体）の厚みは１５〜２５μｍであることが好ましく、銅又は銅合金から構成される負極板（金属箔体）の厚みは７〜１５μｍであることが好ましい。なお、図３、図６に示す電池では、厚みが２０μｍであるアルミニウム箔及び厚みが１０μｍである銅箔を用いている。
【００９４】本実施の形態に用いられる正極集電部材４Ａ及び負極集電部材４Ｂのうちの少なくとも一方を、図５（ａ）、図５（ｅ）に示すように十字形の板状部材、図５（ｂ）、図５（ｆ）に示すようにＹ字形の板状部材、若しくは図５（ｃ）、図５（ｇ）に示すようにＩ字形の板状部材、又は図４、図５（ｄ）、図５（ｈ）に示すように一部に切り欠きを有する円板状部材とすることが好ましい。このことにより、接続部の検査がし易く、また軽量化することが出来、電解液充填時等に電解液が全体に回り易いこととなる。図４において、５は接続部、６１は捲回型内部電極体、７３は電池ケースを示す。
【００９５】本実施の形態のリチウム二次電池製造方法において、正極集電部材と正極板とを接続するに際して、正極集電部材の凸状の接続部にレーザーを照射して凸状の接続部を溶解するときには、例えば図７に示すように、レーザー１１を、正極板１Ａの端部１５の狭幅端面２を含む面の法線３Ａに対して、角度θ（０°＜θ≦９０°）で凸状の接続部５に照射することが好ましく、角度θ（５°≦θ≦８０°）で照射することがさらに好ましく、角度θ（１０°≦θ≦６０°）で照射することが特に好ましく、角度θ（１５°≦θ≦４５°）で照射することが最も好ましい。また、レーザー１１を、正極集電部材４Ａの凸状の接続部５の表面に又はその前後近傍に合焦させることが好ましく、レーザー１１を、正極板１Ａに直接照射しないことが好ましい。
【００９６】更には、正極集電部材４Ａを、その凸状の接続部５が狭幅端面２に略垂直に交差するように配置し、レーザー１１を、狭幅端面２に略垂直に交差するようにレーザー発生装置により走査、すなわち正極集電部材４Ａの凸状の接続部７を走査して照射することが好ましい。このとき、上述した、レーザー１１を、正極板１Ａの狭幅端面２を含む面の法線３Ａに対して、角度θ（０°＜θ≦９０°）で凸状の接続部５に照射することに加え、レーザー１１を、狭幅端面２に略垂直に交差する線に対して、角度が略垂直で凸状の接続部５に照射することが好ましい。これらにより、図１に示すようにろう材を必要とせずに、正極板１Ａと正極集電部材４Ａの溶融体とを溶着させて、正極板１Ａと正極集電部材４Ａとを接続することが出来る。また少なくとも１枚の正極板１Ａを一度の照射によって正極集電部材４Ａと接続することも出来る。さらに、正極板１Ａに損傷を与えずに、正極集電部材４Ａの所定箇所（凸状の接続部５）のみを溶融させて正極板１Ａと正極集電部材４Ａとを溶着・接続することが出来るために、接続の機械的強度を強いものとすることが出来る。
【００９７】なお、本実施の形態でいう「狭幅端面に略垂直に交差する」とは、正（負）極集電部材の接続部と接続される部分に対応する、正（負）極板の端部における狭幅端面の全てについて略垂直に交差することを意味する。
【００９８】本実施の形態のリチウム二次電池製造方法において、負極集電部材と負極板とを接続するに際して、負極集電部材の凸状の接続部にレーザーを照射して凸状の接続部を溶解するときには、例えば図８に示すように、レーザー１１を、負極集電部材４Ｂの接続面９に対向するように形成した負極板１Ｂの端部１５近傍の側面部１３を含む面の法線３Ｂに対して、角度θ（０°≦θ≦３０°）で凸状の接続部５に照射することが好ましく、角度θ（０°≦θ≦１０°）で照射することがさらに好ましく、角度θ（０°≦θ≦５°）で照射することが特に好ましい。また、レーザー１１を、負極集電部材４Ｂの凸状の接続部５の表面に又はその前後近傍に合焦することが好ましく、レーザー１１を、負極金属箔体１Ｂに直接照射しないことが好ましい。
【００９９】さらには、負極集電部材４Ｂを、その凸状の接続部５が側面部１３に略垂直に交差するように配置し、レーザー１１を、側面部１３に略垂直に交差するようにレーザー発生装置により走査、すなわち負極集電部材４の凸状の接続部５を走査して照射することが好ましい。このとき、上述した、レーザー１１を、負極板１Ｂの側面部１３を含む面の法線３Ｂに対して、角度θ（０°≦θ≦３０°）で凸状の接続部５に照射することに加え、レーザー１１を、側面部１３に略垂直に交差する線に対して、角度が略垂直で凸状の接続部５に照射することが好ましい。これらにより、図２に示すようにろう材を必要とせずに、負極板１Ｂと負極集電部材４Ｂの溶融体とを溶着させて、負極板１Ｂと負極集電部材４Ｂとを接続することが出来る。また少なくとも１枚の負極板１Ｂを一度の照射によって負極集電部材４Ｂと接続することも出来る。さらに、負極板１Ｂに損傷を与えずに、負極集電部材４Ｂの所定箇所（凸状の接続部５）のみを溶融させて負極板１Ｂと負極集電部材４Ｂとを溶着・接続することが出来るために、接続の機械的強度を強いものとすることが出来る。なお、「側面部に略垂直に交差する」とは、負極板１Ｂの端部１５の側面部１３のなかで、接続部５と接続する複数の箇所全てについて略垂直に交差することを意味している。
【０１００】また、本実施の形態のリチウム二次電池の製造方法において、負極集電部材の凸状の接続部にレーザーを照射して凸状の接続部を溶融するときに、凸状の接続部の厚みをＬ２（ｍｍ）、レーザーのパワー密度をＥ（ｋＷ／ｍｍ２）としたときに、下記式（５）を満足することが好ましい。レーザーのパワー密度とは照射点におけるパワー密度をいう。下記式（５）を満足するような条件でレーザーを照射することにより、負極板への損傷を抑制し、負極集電部材と負極板との接続部分の機械的強度も強くなるという特性を有する。
【０１０１】
【数５】
Ｌ２≦Ｅ／７ …（５）
【０１０２】なお、更に負極板への損傷を抑制し、接続部分の機械的強度を強くするという観点からは、下記式（６），（７）を満足することが好ましい。
【０１０３】
【数６】
Ｌ２≦Ｅ／９ …（６）
【０１０４】
【数７】
Ｌ２≦Ｅ／１０ …（７）
【０１０５】本実施の形態のリチウム二次電池の製造方法においては、レーザーの照射点のスポット径が１ｍｍ以下であることが好ましい。このことにより、不要な箇所へのレーザーの照射が抑制され、特に負極板の損傷を抑制することができるために、良好な接続状態にすることができる。なお、本発明のリチウム二次電池の製造方法では、隣り合う正極板どうし及び負極板どうしのうちの少なくとも一方が間隙を保持して配列することが好ましい。
【０１０６】また、本実施の形態においては、例えば、図７，８に示すレーザー１１は、連続波であることが好ましい。このことにより、凸状の接続部５の表面にエネルギーを集中させて照射することが出来るために凸状の接続部５を効率的に溶融させることが出来、正極板１Ａ、又は負極板１Ｂの損傷を抑制することが出来る。なお、レーザーの中でも、ＹＡＧレーザーは焦点をよりよく絞ることが出来、焦点からはずれた部分に配置された正極板１Ａ、又は負極板１Ｂの位置ではエネルギー密度はより小さくなり、正極板１Ａ、又は負極板１Ｂの損傷をよりよく抑制することが出来ることから、特に好ましい。
【０１０７】また、本実施の形態のリチウム二次電池の製造方法では、例えば、図７に示すレーザー１１を、連続照射が可能なレーザー発生装置を用いて照射することが好ましく、レーザー１１を、狭幅端面２を含む面に平行な面を走査可能なレーザー発生装置を用いて照射することが好ましい。なお、照射するレーザーの走査速度は、０．１〜１００ｍ／ｍｉｎであることが好ましく、１〜３０ｍ／ｍｉｎであることがさらに好ましく、２〜１０ｍ／ｍｉｎであることが特に好ましい。また、正極集電部材４Ａの接続部５が凸状である場合には、レーザー１１を、凸状の接続部５に沿って、レーザー発生装置により走査して照射することが好ましい。さらに、本発明においては、配列された正極板１Ａの枚数に応じ、正極集電部材４Ａを複数個用意し、複数の正極集電部材４Ａを、それらの凸状の接続部５が狭幅端面２に略垂直に交差するようにして、連続的に配置することが好ましい。これらのことにより、複数枚の正極板１Ａを一度の照射によって接続することが出来ることとなる。
【０１０８】一方、本実施の形態のリチウム二次電池の製造方法では、例えば、図８に示すレーザー１１を、連続照射が可能なレーザー発生装置を用いて照射することが好ましく、レーザー１１を、側面部１３を含む面に平行な面を走査可能なレーザー発生装置を用いて照射することが好ましい。また、負極集電部材４Ｂの接続部５が凸状である場合には、レーザー１１を、凸状の接続部５に沿って、レーザー発生装置により走査して照射することが好ましい。さらに、本発明においては、配列された負極板１Ｂの枚数に応じ、負極集電部材４Ｂを複数個用意し、複数の負極集電部材４Ｂを、それらの凸状の接続部５が側面部１３に略垂直に交差するようにして、連続的に配置することが好ましい。これらのことにより、複数枚の負極板１Ｂを一度の照射によって接続することが出来ることとなる。
【０１０９】第１の発明のリチウム二次電池の製造方法において、正極集電部材の接続部と正極板の端部とを接続するに際して、ろう材等の接続補助材料（接続材）は必要としないが、もちろん使用しても構わない。その場合には、正極集電部材の接続部と正極板の端部との接続を補助する接続材を、正極板の端部及び正極集電部材の接続部のうちの少なくとも一方に塗布し、又は正極板の端部と正極集電部材の接続部との間に挟時させて、正極集電部材の接続部及び接続材にレーザーを照射し、正極集電部材の接続部及び接続材を溶融させて、溶融した正極集電部材の接続部及び接続材を、正極板の端部に溶着させることが好ましい。
【０１１０】また、第１の発明のリチウム二次電池の製造方法において、負極集電部材と負極板とを接続するに際して、ろう材等の接続補助材料（接続材）は必要としないが、もちろん使用しても構わない。その場合には、負極集電部材の接続部と負極板の端部との接続を補助する接続材を、負極板の端部及び負極集電部材の接続部のうちの少なくとも一方に塗布し、又は負極板の端部と負極集電部材の接続部との間に挟時させて、負極集電部材の接続部及び接続材にレーザーを照射し、負極集電部材の接続部及び接続材を溶融させて、溶融した負極集電部材の接続部及び接続材を、負極板の端部に溶着させることが好ましい。
【０１１１】次に、第２の発明のリチウム二次電池の製造方法について説明する。第２の発明のリチウム二次電池の製造方法は、上述したように、少なくとも１枚の金属箔体からそれぞれ構成された正極板及び負極板をセパレータを介して捲回して捲回型内部電極体を形成し、正極板及び負極板のそれぞれの端部を、それらの端部から電流を導出するために、アルミニウムからなる正極集電部材、及び銅からなる負極集電部材のそれぞれの所定箇所（接続部）にそれぞれ接続してリチウム二次電池を製造するものであって、負極板の端部を負極集電部材の接続部に接続するときに、負極集電部材の接続部をパワー密度が３ｋＷ／ｍｍ２以上のレーザーで溶融して、その負極集電部材の接続部を負極板の端部に溶着し、更に、負極集電部材の接続部の表面（接続面）の表面粗さを中心線平均表面粗さＲａで０．０５〜６．３μｍＲａとするものである。
【０１１２】第２の発明のリチウム二次電池の製造方法の一の実施の形態では、上述した第１の発明の実施の形態における場合と同様に、図２に示すように、負極集電部材４Ｂと負極板１Ｂとの接続は、少なくとも１枚の金属箔体から構成される負極板１Ｂの端部１５の近傍を屈曲させて負極集電部材４Ｂの接続部５側（接続面９側）を向けた側面部１３と、負極集電部材４Ｂの接続部５の接続面９と、を所定の位置に配置し、所定のパワー密度のレーザー１１で接続部５を溶融して、接続部５と負極板の端部１５とを溶着することにより行うことが好ましい。このとき側面部１３上の複数箇所と接続面９とが溶着される。
【０１１３】本実施の形態においては、上述した第１の発明の実施の形態における場合と同様に、図８に示すように、負極集電部材４Ｂの接続部５を、負極集電部材４Ｂの負極板１Ｂ側を向く面４Ｄから負極板１Ｂに向かって列状に連続して突出した凸状とし、凸状の接続部５の先端部分に接続面９を形成し、負極板１Ｂの端部１５近傍を屈曲させて負極板１Ｂの端部１５近傍の側面部１３が負極集電部材４Ｂの接続面９に対向するようにし、負極板１Ｂの端部１５近傍の側面部１３と負極集電部材４Ｂの接続面９（接続部５）とを接続することが好ましい。そして、図８に示すように、負極板１Ｂの端部１５と、負極集電部材４Ｂの凸状の接続部５とを接続するときには、凸状の接続部５にレーザー１１を照射し、凸状の接続部５を溶融して、負極集電部材４Ｂの凸状の接続部５と負極板１Ｂの端部１５とを溶着させることが好ましい。さらに、負極集電部材４Ｂにおいて、接続部５が配設される位置は、負極集電部材４Ｂの先端部６であることが、接続面の確認のし易いことから好ましい。図８において、１２は平坦部、Ｌ１は平坦部１２の厚み、Ｌ２は接続部５の厚みを示す。負極集電部材４Ｂは接続部５と平坦部１２とを有する構造となっている。また、凸状の接続部としては、図２に示すように、負極集電部材４Ｂの負極板１Ｂ側を向く面４Ｃから負極板１Ｂに向かって凸状に突出し、且つ負極集電部材４Ｂを外側に延長する方向に延設するように形成した形状も含まれる。
【０１１４】本実施の形態においては、上述した第１の発明の実施の形態における場合と同様に、図８に示すように、負極板１Ｂと負極集電部材４Ｂとを接続するときには、端部１５近傍を屈曲することにより側面部１３と、凸状の接続部５の接続面９とを密着させればよいが、このように側面部１３と接続面９との密着は、上述した第１の発明における「（負極板の）側面部と（負極集電部材の）接続面とを密着させる方法（図１６，１７により説明したもの）」と同様の方法で行うことができる。
【０１１５】本実施の形態のリチウム二次電池の製造方法においては、負極板の端部近傍の側面部と負極集電部材の接続面とを接続するときには、上述した第１の発明の実施の形態における「負極板の端部近傍の側面部と負極集電部材の接続面とを接続するとき」と同様に、負極板の端部近傍の側面部から負極集電部材の方向へ柱状晶が形成されるようにすることが好ましい。
【０１１６】そして、上述した第１の発明の実施の形態における場合と同様に、負極板と負極集電部材との接続部分において、負極板から負極集電部材の方向へ柱状晶を形成することにより、負極板と負極集電部材との接続状態が良好、すなわち、接続部分の機械的強度が強く信頼性に優れたリチウム二次電池を得ることができる。
【０１１７】本実施の形態のリチウム二次電池の製造方法に用いられる負極集電部材の凸状の接続部の形状には、上述した第１の発明の実施の形態における「負極集電部材の凸状の接続部の形状」と同様に、特に制限はない。
【０１１８】本実施の形態のリチウム二次電池においては、上述した第１の発明の実施の形態における場合と同様に、図１４，１５に示すように、負極集電部材４Ｂは凸状の接続部５とそれ以外の平坦部１２とを有する形状であり、凸状の接続部５の厚み（Ｌ２）と、平坦部１２の厚み（Ｌ１）との差を０．１ｍｍ以上とすることが好ましく、０．６ｍｍ以上とすることがさらに好ましく、０．８ｍｍ以上とすることが特に好ましい。凸状の接続部５と平坦部１２との厚みの差が０．１ｍｍ未満である場合には、凸状の接続部５の形状的な特徴が発揮されず、凸状の接続部５と負極板１Ｂとの接触状態が不安定となるために好ましくない。また、負極集電部材４Ｂの凸状の接続部５と平坦部１２との厚みの差の上限値については特に限定されないが、負極集電部材の加工精度及び強度等から適宜設定されればよく、例えば３ｍｍ以下であればよい。
【０１１９】接続に際して負極板に負極集電部材を押さえ付けるときに、負極集電部材の変形や損傷等の発生を防止するといった観点からは、平坦部の厚み（Ｌ１）を０．２ｍｍ以上とすることが好ましく、０．３ｍｍ以上とすることがさらに好ましく、０．４ｍｍ以上とすることが特に好ましい。なお、平坦部の厚みの上限値については特に限定されないが、溶接部分とは直接的には関係のない部分であるため負極集電部材の強度及び重量等から適宜設定されればよく、例えば２ｍｍ以下であればよい。
【０１２０】また、負極集電部材４Ｂの凸状の接続部の厚み（Ｌ２）を０．４ｍｍ以上とすることが好ましく、０．５ｍｍ以上とすることがさらに好ましく、０．６ｍｍ以上とすることが特に好ましい。このことにより、より強固に接続することが出来る。なお、凸状の接続部の厚みの上限値については特に限定されないが、照射されるレーザーのパワーの限界から適宜設定されればよい。
【０１２１】本実施の形態のリチウム二次電池に用いられる負極集電部材のレーザー照射部（接続部）の形状は、第１の発明の実施の形態において、図８，１２，１３により説明した形状と同様の形状を好適な例として挙げることが出来る。
【０１２２】本実施の形態においては、上述した第１の発明の実施の形態における場合と同様に、正極板に正極集電部材と同じ材質のアルミニウム又はアルミニウム合金を使用し、負極板に負極集電部材と同じ材質の銅又は銅合金を使用した場合には、金属板（金属箔体）と集電部材とが同種金属から構成されることとなるために、金属板（金属箔体）と集電部材とがよりよく溶着され、電流導出部分の機械的強度を強くすることが出来る。この場合、アルミニウム又はアルミニウム合金から構成される正極板（金属箔体）の厚みは１５〜２５μｍであることが好ましく、銅又は銅合金から構成される負極板（金属箔体）の厚みは７〜１５μｍであることが好ましい。
【０１２３】本実施の形態においては、上述した第１の発明の実施の形態における場合と同様に、図５（ａ）、図５（ｅ）に示すように、負極集電部材４Ｂを、十字形の板状部材にすることが好ましい。また、図５（ｂ）、図５（ｆ）に示すように負極集電部材４ＢをＹ字形の板状部材とするか、又は、図５（ｃ）、図５（ｇ）に示すように負極集電部材４ＢをＩ字形の板状部材にすることが好ましい。また、図４、図５（ｄ）、図５（ｈ）に示すように、負極集電部材４Ｂを、一部に切り欠きを有する円板状部材とすることが好ましい。このことにより、接続部の検査がし易く、また軽量化することが出来、電解液充填時等に電解液が全体に回り易いこととなる。
【０１２４】本実施の形態のリチウム二次電池製造方法においては、負極集電部材と負極板とを接続するに際して、負極集電部材の凸状の接続部にレーザーを照射して凸状の接続部を溶解するときには、上述した第１の発明の実施の形態における場合と同様に、例えば図８に示すように、レーザー１１を、負極集電部材４Ｂの接続面９に対向するように形成した負極板１Ｂの端部１５近傍の側面部１３を含む面の法線３Ｂに対して、角度θ（０°≦θ≦３０°）で凸状の接続部５に照射することが好ましく、角度θ（０°≦θ≦１０°）で照射することがさらに好ましく、角度θ（０°≦θ≦５°）で照射することが特に好ましい。また、レーザー１１を、負極集電部材４Ｂの凸状の接続部５の表面に又はその前後近傍に合焦することが好ましく、レーザー１１を、負極金属箔体１Ｂに直接照射しないことが好ましい。
【０１２５】さらには、上述した第１の発明の実施の形態における場合と同様に、負極集電部材４Ｂを、その凸状の接続部５が側面部１３に略垂直に交差するように配置し、レーザー１１を、側面部１３に略垂直に交差するようにレーザー発生装置により走査、すなわち負極集電部材４の凸状の接続部５を走査して照射することが好ましい。このとき、上述した、レーザー１１を、負極板１Ｂの側面部１３を含む面の法線３Ｂに対して、角度θ（０°≦θ≦３０°）で凸状の接続部５に照射することに加え、レーザー１１を、側面部１３に略垂直に交差する線に対して、角度が略垂直で凸状の接続部５に照射することが好ましい。これらにより、図２に示すようにろう材を必要とせずに、負極板１Ｂと負極集電部材４Ｂの溶融体とを溶着させて、負極板１Ｂと負極集電部材４Ｂとを接続することが出来る。また少なくとも１枚の負極板１Ｂを一度の照射によって負極集電部材４Ｂと接続することも出来る。さらに、負極板１Ｂに損傷を与えずに、負極集電部材４Ｂの所定箇所（凸状の接続部５）のみを溶融させて負極板１Ｂと負極集電部材４Ｂとを溶着・接続することが出来るために、接続の機械的強度を強いものとすることが出来る。
【０１２６】また、本実施の形態のリチウム二次電池の製造方法において、負極集電部材の凸状の接続部にレーザーを照射して凸状の接続部を溶融するときに、凸状の接続部の厚みをＬ２（ｍｍ）、レーザーのパワー密度をＥ（ｋＷ／ｍｍ２）としたときに、下記式（８）を満足することが好ましい。レーザーのパワー密度とは照射点におけるパワー密度をいう。下記式（８）を満足するような条件でレーザーを照射することにより、負極板への損傷を抑制し、負極集電部材と負極板との接続部分の機械的強度も強くなるという特性を有する。
【０１２７】
【数８】
Ｌ２≦Ｅ／７ …（８）
【０１２８】なお、更に負極板への損傷を抑制し、接続部分の機械的強度を強くするという観点からは、下記式（９），（１０）を満足することが好ましい。
【０１２９】
【数９】
Ｌ２≦Ｅ／９ …（９）
【０１３０】
【数１０】
Ｌ２≦Ｅ／１０ …（１０）
【０１３１】本実施の形態のリチウム二次電池の製造方法においては、レーザーの照射点のスポット径が１ｍｍ以下であることが好ましい。このことにより、不要な箇所へのレーザーの照射が抑制され、特に負極板の損傷を抑制することができるために、良好な接続状態にすることができる。なお、本発明のリチウム二次電池の製造方法では、隣り合う正極板どうし及び負極板どうしのうちの少なくとも一方が間隙を保持して配列することが好ましい。
【０１３２】また、本実施の形態においては、例えば、上述した第１の発明の実施の形態における場合と同様に、図８に示すレーザー１１は、連続波であることが好ましい。このことにより、凸状の接続部５の表面にエネルギーを集中させて照射することが出来るために凸状の接続部５を効率的に溶融させることが出来、負極板１Ｂの損傷を抑制することが出来る。なお、レーザーの中でも、ＹＡＧレーザーは焦点をよりよく絞ることが出来、焦点からはずれた部分に配置された負極板１Ｂの位置ではエネルギー密度はより小さくなり、負極板１Ｂの損傷をよりよく抑制することが出来ることから、特に好ましい。
【０１３３】一方、本実施の形態のリチウム二次電池の製造方法では、上述した第１の発明の実施の形態における場合と同様に、例えば、図８に示すレーザー１１を、連続照射が可能なレーザー発生装置を用いて照射することが好ましく、レーザー１１を、側面部１３を含む面に平行な面を走査可能なレーザー発生装置を用いて照射することが好ましい。また、負極集電部材４Ｂの接続部５が凸状である場合には、レーザー１１を、凸状の接続部５に沿って、レーザー発生装置により走査して照射することが好ましい。さらに、本発明においては、配列された負極板１Ｂの枚数に応じ、負極集電部材４Ｂを複数個用意し、複数の負極集電部材４Ｂを、それらの凸状の接続部５が側面部１３に略垂直に交差するようにして、連続的に配置することが好ましい。これらのことにより、複数枚の負極板１Ｂを一度の照射によって接続することが出来ることとなる。
【０１３４】また、第２の発明のリチウム二次電池の製造方法において、負極集電部材と負極板とを接続するに際して、ろう材等の接続補助材料（接続材）は必要としないが、もちろん使用しても構わない。その場合には、負極集電部材の接続部と負極板の端部との接続を補助する接続材を、負極板の端部及び負極集電部材の接続部のうちの少なくとも一方に塗布し、又は負極板の端部と負極集電部材の接続部との間に挟時させて、負極集電部材の接続部及び接続材にレーザーを照射し、負極集電部材の接続部及び接続材を溶融させて、溶融した負極集電部材の接続部及び接続材を、負極板の端部に溶着させることが好ましい。
【０１３５】本実施の形態のリチウム二次電池の製造方法においては、上述した第１の発明の実施の形態における場合と同様に、図３に示すように、内部端子６９Ａ，６９Ｂ、外部端子７０Ａ，７０Ｂ、及び電池蓋７１Ａ，７１Ｂを有する電極蓋を作製し、捲回型内部電極体６１の正極板１Ａに正極集電部材４Ａを接続し負極板１Ｂに負極集電部材４Ｂを接続したものの、正極集電部材４Ａ及び負極集電部材４Ｂを、内部端子６９Ａ及び６９Ｂに各々電極リード部材７２を用いて接続することが好ましい。
【０１３６】また、第２の発明においては、上述した第１の発明の実施の形態における場合と同様に、図６に示すように、集電部材５４に直接外部端子を配設し、電池外部に直接電流を導出するように形成して、集電部材５４を電極蓋と兼用するようにしてもよい。
【０１３７】上述した第２の発明の一の実施の形態において、上述した条件以外の、正極板、正極集電部材、これらの接続方法、その他リチウム二次電池製造方法に関する各条件は、第１の発明の実施の形態と同様にすることが好ましい。
【０１３８】上述した第１の発明及び第２の発明は、具体的には、捲回型或いは積層型の内部電極体に好適に用いられ、その中でも２Ａｈ以上の容量を有するものに好適に用いられる。電池の用途としても特に制限はないが、電池を直列に接続して大きな出力を出すことを目的とし、多数の電池を積載するために省スペース性が要求される車載用大容量電池として、エンジン起動用に、電気自動車又はハイブリッド電気自動車のモータ駆動用に特に好適に用いることが出来る。
【０１３９】
【実施例】以下、本発明（第１の発明及び第２の発明）を実施例により具体的に説明するが、本発明はこれら実施例に限定されるものではない。
【０１４０】
（実施例１〜９、比較例１，２）
レーザーとして連続波のＹＡＧレーザーを使用し、縦５０ｍｍ、横１００ｍｍ、厚み１０ｍｍのアルミニウム角板をサンプルとして、ＹＡＧレーザーによるアルミニウム角板の溶融試験（溶融体積測定）を行った。ＹＡＧレーザーの照射点におけるエネルギー密度（レーザーパワー密度）として、表１に示すように２〜１２（ｋＷ／ｍｍ２）の間の１１種類を採用し（実施例１〜９、比較例１，２）、各レーザーパワー密度において、表１に示すように、走査速度（ｍ／ｍｉｎ）及び接続面の状態を変化させて、アルミニウム角板の溶融体積（単位：ｍｍ３／ｓ）を測定した。結果を表１に示す。
【０１４１】ＹＡＧレーザーとしては、ＨＡＡＳ ＨＬＤ３５０４を使用した。また、レーザーはサンプルに対して直角に入射させた。
【０１４２】サンプルの表面において、標準面とは、表面粗さが中心線平均表面粗さＲａで０．４１μｍＲａの面をいい、鏡面とは、表面粗さが中心線平均表面粗さＲａで：０．０６μｍＲａの面をいい、酸化面とはアルミニウムの表面が酸化されることにより表面粗さが中心線平均表面粗さＲａで：６．１８μｍになった面をいう。
【０１４３】中心線平均表面粗さＲａは以下の方法で測定した。
【０１４４】Ｔａｙｌｏｒ Ｈｏｂｓｏｎ社製 フォームタリサーフＳ５で、ＪＩＳ Ｂ ０６０１及び、ＩＳＯ Ｒ １１０１に基づき測定した。
【０１４５】
（実施例１０〜１８、比較例３，４）
サンプルとして、縦５０ｍｍ、横１００ｍｍ、厚み１０ｍｍの銅角板を使用した以外は、上記実施例１〜９、比較例１，２と同様の条件で、銅角板の溶融体積（単位：ｍｍ３／ｓ）を測定した。結果を表２に示す。
【０１４６】
【表１】

Figure 2004220953
【０１４７】
【表２】
Figure 2004220953
【０１４８】以上より、アルミニウム角板をＹＡＧレーザーで溶融する場合には、標準面、鏡面及び酸化面のそれぞれにおいて、５ｋＷ／ｍｍ２以上のパワー密度を必要とすることがわかる。
【０１４９】また、銅角板をＹＡＧレーザーで溶融する場合には、標準面、鏡面及び酸化面のそれぞれにおいて、３ｋＷ／ｍｍ２以上のパワー密度を必要とすることがわかる。
【０１５０】これらにより、アルミニウム又はアルミニウム合金からなる正極集電部材の接続部をレーザーで溶融して、正極板に溶着（接続）する場合には、５ｋＷ／ｍｍ２以上のパワー密度を必要とすることがわかる。また、銅又は銅号金からなる負極集電部材の接続部をレーザーで溶融して、負極板に溶着（接続）する場合には、３ｋＷ／ｍｍ２以上のパワー密度を必要とすることがわかる。そして、接続面の表面粗さは、中心線平均表面粗さＲａで０．０５〜６．３μｍＲａである。これらの条件を基準に、パワー密度の低いレーザーで上記溶着を行うことにより、正極板や負極板の損傷を防止することができるため、歩留まりを向上させることができ、仕上がり状態も良好になる
【０１５１】
【発明の効果】以上説明したように、本発明によって、各電極板の端部と集電部材を直接的に接続して内部電極体から電流を導出するという構成を採用し、各電極板と集電部材とを接続するときに、各接続面の表面粗さを所定の範囲とし、所定のエネルギー密度のレーザーを使用して各電極板と集電部材とを溶着するようにしたため、生産性に優れたリチウム二次電池の製造方法を提供することができる。
【図面の簡単な説明】
【図１】第１の発明のリチウム二次電池の製造方法における正極板と正極集電部材との接続の一実施例を模式的に示す斜視図である。
【図２】第１の発明及び第２の発明のリチウム二次電池の製造方法における負極板と負極集電部材との接続の一実施例を模式的に示す斜視図である。
【図３】第１の発明及び第２の発明のリチウム二次電池の製造方法により得られるリチウム二次電池の一実施形態を示す断面図である。
【図４】第１の発明及び第２の発明のリチウム二次電池の製造方法における捲回型電極体と正極集電部材とを示す斜視図である。
【図５】第１の発明及び第２の発明のリチウム二次電池の製造方法に用いられる集電部材の例を示す模式図である。
【図６】第１の発明及び第２の発明のリチウム二次電池の製造方法により得られるリチウム二次電池の別の実施形態を示す断面図である。
【図７】第１の発明のリチウム二次電池の製造方法において正極集電部材と正極板とをレーザーにより溶着する方法を模式的に示す斜視図である。
【図８】第１の発明及び第２の発明のリチウム二次電池の製造方法において負極集電部材と負極板とをレーザーにより溶着する方法を模式的に示す斜視図である。
【図９】第１の発明のリチウム二次電池の製造方法において正極集電部材と正極板とをレーザーにより溶着する別の方法を模式的に示す斜視図である。
【図１０】第１の発明のリチウム二次電池の製造方法において正極集電部材と正極板とをレーザーにより溶着する別の方法を模式的に示す斜視図である。
【図１１】第１の発明のリチウム二次電池の製造方法において正極集電部材と正極板とをレーザーにより溶着する別の方法を模式的に示す斜視図である。
【図１２】第１の発明及び第２の発明のリチウム二次電池の製造方法において負極集電部材と負極板とをレーザーにより溶着する別の方法を模式的に示す斜視図である。
【図１３】第１の発明及び第２の発明のリチウム二次電池の製造方法において負極集電部材と負極板とをレーザーにより溶着する別の方法を模式的に示す斜視図である。
【図１４】第１の発明及び第２の発明のリチウム二次電池の製造方法に用いられる集電部材の、凸状の接続部の形状の一例を示す模式図である。
【図１５】第１の発明及び第２の発明のリチウム二次電池の製造方法に用いられる集電部材の、凸状の接続部の形状の別の例を示す模式図である。
【図１６】金属板（金属箔体）を屈曲させる方法の一例を説明する模式図である。
【図１７】金属板（金属箔体）を屈曲させる方法の別の例を説明する模式図である。
【図１８】従来のリチウム二次電池の製造方法により得られるリチウム二次電池の一実施形態を示す断面図である。
【図１９】捲回型の内部電極体の一例を示す斜視図である。
【符号の説明】
１Ａ…正極板、１Ｂ…負極板、２…狭幅端面、３Ａ…狭幅端面を含む面の法線、３Ｂ…側面部を含む面の法線、４Ａ…正極集電部材、４Ｂ…負極集電部材、４Ｃ…正極集電部材の正極板側を向く面、４Ｄ…負極集電部材の負極板側を向く面、５…接続部、６…先端部、９…接続面、１１…レーザー、１２…平坦部、１３…側面部、１５…端部、３１Ａ…正極集電部材、３１Ｂ…負極集電部材、３２…先端部、３３…接続部、３４…レーザー、３５…レーザー、４１…正極集電部材、４２…レーザー、５１Ａ…正極集電部材、５１Ｂ…負極集電部材、５２…接続部、５３…レーザー、５４…集電部材、６１…捲回型内部電極体、６２…正極板、６３…負極板、６４…セパレータ、６５…正極用集電タブ、６６…負極用集電タブ、６７…巻芯、６８…リチウム二次電池、６９Ａ…正極内部端子、６９Ｂ…負極内部端子、７０Ａ…正極外部端子、７０Ｂ…負極外部端子、７１Ａ…正極電池蓋、７１Ｂ…負極電池蓋、７２…電極リード部材、７３…電池ケース、７４…くびれ加工部、７５…放圧孔、７６…弾性体（パッキン）、７７…絶縁性ポリマーフィルム、７８…放圧弁、７９…金属箔、Ｌ１…平坦部の厚み、Ｌ２…凸状の接続部の厚み、θ…レーザーと法線３Ａ又は法線３Ｂとにより形成される角度。[0001]
The present invention relates to a method for manufacturing a lithium secondary battery (hereinafter, also simply referred to as "battery"), and more particularly, to a method for manufacturing a lithium secondary battery having excellent productivity.
[0002]
2. Description of the Related Art In recent years, there has been an increasing demand for resource saving and energy saving for the protection of the global environment, and for driving motors of electric vehicles and hybrid electric vehicles (hereinafter, also simply referred to as "electric vehicles, etc."). A lithium secondary battery is being developed as a power supply.
[0003] This lithium secondary battery is constructed by winding or laminating a positive electrode plate and a negative electrode plate inside thereof through a separator made of a porous polymer film so that the positive electrode plate and the negative electrode plate do not come into direct contact with each other. (Hereinafter, simply referred to as an “electrode body”).
Conventionally, as shown in FIG. 19, for example, a wound internal electrode body 61 is produced by winding a positive electrode plate 62 and a negative electrode plate 63 with a winding core 67 as a core via a separator 64. Each of the positive electrode plate 62 and the negative electrode plate 63 (hereinafter, also referred to as “electrode plates 62, 63”) has at least one positive electrode current collecting tab 65 and a negative electrode current collecting tab 66 (hereinafter, “collecting electrode”). (Also referred to as “electric tabs 65 and 66”) (for example, see Patent Document 1). Then, as shown in FIG. 18, the opposite ends of the current collecting tabs 65 and 66 connected to the positive electrode plate 62 and the negative electrode plate 63 (see FIG. 19) are attached to the internal terminals 69A and 69B and the like.
Reference numeral 76 denotes an elastic body (packing), reference numeral 77 denotes an insulating polymer film, reference numeral 78 denotes a pressure relief valve, and reference numeral 79 denotes a metal foil. In addition, other reference numerals indicate the same reference numerals as those described later with reference to FIG.
The electrode plate is formed by using a metal foil such as aluminum or the like for the positive electrode plate and copper or nickel or the like for the negative electrode plate as a current collecting substrate and applying an electrode active material to each of them. Is disposed on at least one side of such a current collecting substrate.
However, since the current collecting tabs need to be attached one by one to the electrode plate when winding the electrode body, there is a problem that the process is complicated. In addition, the end of the current collecting tab on the opposite side connected to the electrode plate needs to be bundled by aligning the plurality of current collecting tabs, and to be attached to the internal terminals by driving connection using rivets or the like. However, there is a problem that the process is similarly complicated, and it is not easy to connect to a low resistance.
[0008]
[Patent Document 1]
JP 2001-85042 A
[0009]
SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem, and an object thereof is to directly connect an end of each electrode plate to a current collecting member. By adopting a configuration that derives current from the internal electrode body, when connecting each electrode plate and the current collecting member, the surface roughness of each connection surface is within a predetermined range, and a laser with a predetermined energy density is used. It is an object of the present invention to provide a method for manufacturing a lithium secondary battery having excellent productivity by welding each electrode plate and a current collecting member.
[0010]
In order to achieve the above object, the present invention provides the following method for manufacturing a lithium secondary battery.
[0011]
[1] A positive electrode plate and a negative electrode plate each composed of at least one metal foil body are wound or laminated via a separator to form a wound internal electrode body or a laminated internal electrode body, In order to derive a current from the ends of the positive electrode current collector and the negative electrode current collector made of aluminum or an aluminum alloy and a negative electrode current collector made of copper or a copper alloy, respectively, ), Wherein the surface roughness of the surface (connection surface) of the connection portion of the positive electrode current collector is 0.05 to 6.3 μm Ra as a center line average surface roughness Ra. And the power density of the connection portion of the positive electrode current collector is 5 kW / mm. 2 The above laser is melted, and the end of the positive electrode plate is connected to the connection of the positive electrode current collector by welding the connection of the positive electrode current collector to the end of the positive electrode plate. Manufacturing method for a lithium secondary battery (hereinafter, sometimes referred to as a first invention).
[0012]
[2] An internal terminal for deriving a current from at least one of the positive electrode current collecting member and the negative electrode current collecting member, and an electrode lead member provided on at least one of the positive electrode current collecting member and the negative electrode current collecting member. The method for producing a lithium secondary battery according to [1], wherein the lithium secondary battery is connected using:
[0013]
[3] The method for producing a lithium secondary battery according to [1], wherein an external terminal is provided on at least one of the positive electrode current collecting member and the negative electrode current collecting member so as to directly draw a current outside the battery. .
[0014]
[4] The connecting portion of the positive electrode current collecting member is formed in a convex shape that continuously protrudes in a line toward the positive electrode plate of the positive electrode current collecting member, and the connecting surface is provided at the tip of the convex connecting portion. The method for manufacturing a lithium secondary battery according to any one of [1] to [3], wherein the connection surface and the narrow end face of the end of the positive electrode plate are connected to each other.
[0015]
[5] The convex connection portion of the positive electrode current collecting member is irradiated with the laser to melt the convex connection portion, so that the convex connection portion is welded to an end of the positive electrode plate. The method for producing a lithium secondary battery according to [4].
[0016]
[6] At least one of the positive electrode current collecting member and the negative electrode current collecting member is a cross-shaped, Y-shaped, or I-shaped plate-shaped member, or a disk-shaped member partially cutout [ The method for producing a lithium secondary battery according to any one of [1] to [5].
[0017]
[7] The positive electrode current collecting member has a shape having the convex connection portion and the other flat portion, and the thickness (L 2 ) And the thickness of the flat portion (L 1 The method for producing a lithium secondary battery according to any one of [4] to [6], wherein the difference from the above is 0.1 mm or more.
[0018]
[8] The thickness (L) of the flat portion of the positive electrode current collector 1 ) Is set to 0.4 mm or more.
[0019]
[9] The thickness (L) of the convex connection portion in the positive electrode current collecting member 2 ) Is set to 0.6 mm or more, the method for producing a lithium secondary battery according to [7] or [8].
[0020]
[10] When irradiating the laser to the convex connecting portion of the positive electrode current collecting member to melt the convex connecting portion, the surface of the positive electrode plate including the narrow end surface of the end portion of the positive electrode plate is formed. The method for producing a lithium secondary battery according to any one of [5] to [9], wherein the laser is irradiated at an angle θ (0 <θ ≦ 90 °) with respect to a normal line.
[0021]
[11] The method for producing a lithium secondary battery according to any one of [5] to [10], wherein a diameter of a range (irradiation point) irradiated with the laser is 1 mm or less.
[0022]
[12] At least one of an end portion of the positive electrode plate and the connection portion of the positive electrode current collector includes a connecting member that assists connection between the connection portion of the positive electrode current collector and an end of the positive electrode plate. Applied, or sandwiched between the end portion of the positive electrode plate and the connection portion of the positive electrode current collector, irradiating the laser to the connection portion and the connection material of the positive electrode current collector, Melting the connection portion and the connection material of the positive electrode current collector, and welding the melted connection portion and the connection material of the positive electrode current collector to an end of the positive electrode plate [1] to [11] ] The method for producing a lithium secondary battery according to any one of the above items.
[0023]
[13] The surface roughness of the surface (connection surface) of the connection portion of the negative electrode current collecting member is set to 0.05 to 6.3 μm Ra as a center line average surface roughness Ra, and the connection portion of the negative electrode current collecting member is subjected to power density. Is 3 kW / mm 2 The end of the negative electrode plate is connected to the connection portion of the negative electrode current collector by melting with the above laser and welding the connection portion of the negative electrode current collector to the end of the negative electrode plate [1]. [12] The method for producing a lithium secondary battery according to any one of [12] to (12).
[0024]
[14] The connecting portion of the negative electrode current collecting member is formed in a convex shape that continuously protrudes in a line toward the negative electrode plate of the negative electrode current collecting member, and the connecting surface is provided at a tip portion of the convex connecting portion. Is formed, and the vicinity of the end of the negative electrode plate is bent so that the side surface near the end of the negative electrode plate faces the connection surface of the negative electrode current collecting member, and the side surface near the end of the negative electrode plate is formed. The method for manufacturing a lithium secondary battery according to [13], wherein the unit and the connection surface of the negative electrode current collector are connected.
[0025]
[15] When connecting the side surface near the end of the negative electrode plate to the connection surface of the negative electrode current collector, a columnar shape is formed from the side surface near the end of the negative electrode current collector toward the negative electrode current collector. The method for producing a lithium secondary battery according to [14], wherein a crystal is formed.
[0026]
[16] By irradiating the laser to the convex connection portion of the negative electrode current collecting member and melting the convex connection portion, the convex connection portion is welded to an end of the negative electrode plate. The method for producing a lithium secondary battery according to [14] or [15].
[0027]
[17] At least one of the positive electrode current collecting member and the negative electrode current collecting member has a shape having the convex connection portion and another flat portion, and the thickness of the convex connection portion (L 2 ) And the thickness of the flat portion (L 1 The method for producing a lithium secondary battery according to any one of [14] to [16], wherein the difference from the above is 0.1 mm or more.
[0028]
[18] The thickness (L) of the flat portion of the negative electrode current collector 1 ) Is 0.2 mm or more.
[0029]
[19] The thickness (L) of the convex connection portion of the negative electrode current collector 2 ) Is 0.4 mm or more, the method for producing a lithium secondary battery according to [17] or [18].
[0030]
[20] The negative electrode current collector is formed so as to face the connection surface of the negative electrode current collector when the convex connection is melted by irradiating the convex connection with the laser. The lithium according to any one of [16] to [19], wherein the laser is irradiated at an angle θ (0 ≦ θ ≦ 30 °) with respect to a normal to a surface including a side surface near the end of the negative electrode plate. A method for manufacturing a secondary battery.
[0031]
[21] When irradiating the laser to the convex connection portion of the negative electrode current collector and melting the convex connection portion, the thickness of the convex connection portion is set to L. 2 (Mm), the power density of the laser is E (kW / mm). 2 ), The method for producing a lithium secondary battery according to any one of [16] to [20], which satisfies the following expression (3).
[0032]
[Equation 3]
L 2 ≦ E / 7 (3)
[0033]
[22] The method for producing a lithium secondary battery according to any one of [16] to [21], wherein a diameter of a range (irradiation point) irradiated with the laser is 1 mm or less.
[0034]
[23] At least one of an end portion of the negative electrode plate and the connection portion of the negative electrode current collecting member may include a connecting material that assists connection between the connection portion of the negative electrode current collecting member and an end portion of the negative electrode plate. Applied, or sandwiched between the end portion of the negative electrode plate and the connection portion of the negative electrode current collector, irradiating the laser to the connection portion and the connection material of the negative electrode current collector, Melting the connection part and the connection material of the negative electrode current collector, and welding the melted connection part and the connection material of the negative electrode current collector to an end of the negative electrode plate [13] to [22] ] The method for producing a lithium secondary battery according to any one of the above items.
[0035]
[24] The positive electrode plate and the negative electrode plate each composed of at least one metal foil body are wound or laminated with a separator interposed therebetween to form a wound internal electrode body or a laminated internal electrode body, In order to derive a current from the ends of the positive electrode current collector and the negative electrode current collector made of aluminum or an aluminum alloy and a negative electrode current collector made of copper or a copper alloy, respectively, ), Wherein the surface roughness of the surface (connection surface) of the connection portion of the negative electrode current collector is defined as a center line average surface roughness Ra of 0.05 to 6.3 μm Ra. The power density of the connection portion of the negative electrode current collector is 3 kW / mm. 2 The above laser is melted, and a connection portion of the negative electrode current collector is welded to an end of the negative electrode plate to thereby connect an end of the negative electrode plate to a connection portion of the negative electrode current collector. Of manufacturing a lithium secondary battery.
[0036]
[25] An internal terminal for deriving a current from at least one of the positive electrode current collecting member and the negative electrode current collecting member, and an electrode lead member provided on at least one of the positive electrode current collecting member and the negative electrode current collecting member. The method for producing a lithium secondary battery according to [24], wherein the lithium secondary battery is connected using:
[0037]
[26] The method for manufacturing a lithium secondary battery according to [24], wherein an external terminal is provided on at least one of the positive electrode current collecting member and the negative electrode current collecting member so as to directly lead a current to the outside of the battery. .
[0038]
[27] The connecting portion of the negative electrode current collecting member has a convex shape that continuously protrudes in a row toward the negative electrode plate of the negative electrode current collecting member, and the connecting surface is provided at the tip of the convex connecting portion. Is formed, and the vicinity of the end of the negative electrode plate is bent so that the side surface near the end of the negative electrode plate faces the connection surface of the negative electrode current collecting member, and the side surface near the end of the negative electrode plate is formed. The method for producing a lithium secondary battery according to any one of [24] to [26], wherein the connecting part connects the connection surface of the negative electrode current collecting member.
[0039]
[28] When connecting the side surface near the end of the negative electrode plate to the connection surface of the negative electrode current collecting member, a columnar shape is formed from the side surface near the end of the negative electrode plate toward the negative electrode current collecting member. The method for producing a lithium secondary battery according to [27], wherein a crystal is formed.
[0040]
[29] The laser is applied to the convex connection portion of the negative electrode current collecting member to melt the convex connection portion, thereby welding the convex connection portion to an end of the negative electrode plate. The method for producing a lithium secondary battery according to [27] or [28].
[0041]
[30] At least one of the positive electrode current collecting member and the negative electrode current collecting member is a cross-shaped, Y-shaped, or I-shaped plate-shaped member, or a disk-shaped member having a cutout in a part thereof [ 24] The method for producing a lithium secondary battery according to any one of [29].
[0042]
[31] The negative electrode current collector is formed into a shape having the convex connection portion and the other flat portion, and the thickness (L 2 ) And the thickness of the flat portion (L 1 The method according to any one of [27] to [30], wherein the difference from the lithium secondary battery is 0.1 mm or more.
[0043]
[32] The thickness (L) of the flat portion of the negative electrode current collector 1 ) Is 0.2 mm or more.
[0044]
[33] The thickness (L) of the convex connection portion of the negative electrode current collector 2 ) Is at least 0.4 mm, the method for producing a lithium secondary battery according to [31] or [32].
[0045]
[34] When the convex connection portion of the negative electrode current collector is irradiated with the laser to melt the convex connection portion, it is formed so as to face the connection surface of the negative electrode current collector. The lithium according to any one of [29] to [33], wherein the laser is irradiated at an angle θ (0 ≦ θ ≦ 30 °) with respect to a normal to a surface including a side surface near the end of the negative electrode plate. A method for manufacturing a secondary battery.
[0046]
[35] When irradiating the laser to the convex connection portion of the negative electrode current collector to melt the convex connection portion, the thickness of the convex connection portion is set to L. 2 (Mm), the power density of the laser is E (kW / mm). 2 ), The method for producing a lithium secondary battery according to any one of [29] to [34], which satisfies the following expression (4).
[0047]
(Equation 4)
L 2 ≦ E / 7 (4)
[0048]
[36] The method for manufacturing a lithium secondary battery according to any one of [29] to [35], wherein a diameter of a range (irradiation point) irradiated with the laser is 1 mm or less.
[0049]
[37] At least one of an end portion of the negative electrode plate and the connection portion of the negative electrode current collecting member may include a connecting member that assists connection between the connection portion of the negative electrode current collecting member and an end portion of the negative electrode current collecting member. Applied, or sandwiched between the end portion of the negative electrode plate and the connection portion of the negative electrode current collector, irradiating the laser to the connection portion and the connection material of the negative electrode current collector, Melting the connection part and the connection material of the negative electrode current collector, and welding the melted connection part and the connection material of the negative electrode current collector to an end of the negative electrode plate [24] to [36] ] The method for producing a lithium secondary battery according to any one of the above items.
[0050]
[38] The method for producing a lithium secondary battery according to any one of [1] to [37], wherein the laser is a continuous wave.
[0051]
[39] The method for producing a lithium secondary battery according to any one of [1] to [38], wherein the laser is a YAG laser.
[0052]
[40] The method for producing a lithium secondary battery according to any one of [1] to [39], wherein a battery capacity of the lithium secondary battery is 2 Ah or more.
[0053]
[41] The method for producing a lithium secondary battery according to any one of [1] to [40], wherein the lithium secondary battery is a vehicle-mounted battery.
[0054]
[42] The method for producing a lithium secondary battery according to [41], wherein the lithium secondary battery is a battery for an electric vehicle or a hybrid electric vehicle.
[0055]
[43] The method for producing a lithium secondary battery according to [41] or [42], wherein the lithium secondary battery is an engine starting battery.
As described above, the configuration in which the end portion of each electrode plate is directly connected to the current collecting member to derive a current from the internal electrode body is adopted, and when the positive electrode plate and the positive electrode current collecting member are connected. In addition, since the surface roughness of the connection surface is set to a predetermined range, and the laser having a predetermined energy density is used to weld the positive electrode plate and the positive electrode current collecting member (first invention), the productivity is excellent. A method for manufacturing a lithium secondary battery can be provided. In addition, by adopting a configuration in which an end of each electrode plate and the current collecting member are directly connected to derive a current from the internal electrode body, when connecting the negative electrode plate and the negative electrode current collecting member, Since the negative electrode plate and the negative electrode current collecting member are welded to each other using a laser having a predetermined surface roughness and a predetermined energy density (second invention), a lithium secondary battery excellent in productivity can be obtained. A manufacturing method can be provided.
[0057]
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention (first and second inventions) will be specifically described below with reference to the drawings, but the present invention is not limited to the following embodiments. However, it should be understood that design changes, improvements, and the like can be made appropriately based on ordinary knowledge of those skilled in the art without departing from the spirit of the present invention.
In the method of manufacturing a lithium secondary battery according to the first invention, a positive electrode plate and a negative electrode plate each composed of at least one metal foil are wound via a separator to form a wound internal electrode. Then, in order to derive a current from each of the ends of the positive electrode plate and the negative electrode plate, a predetermined portion (connecting portion) of each of a positive electrode current collecting member made of aluminum and a negative electrode current collecting member made of copper is connected. ) To manufacture a lithium secondary battery. When the end of the positive electrode plate is connected to the connection of the positive electrode current collector, the power density of the connection of the positive electrode current collector is 5 kW / mm 2 It is melted by the above laser, the connection part of the positive electrode current collector is welded to the end of the positive electrode plate, and the surface roughness (connection surface) of the connection part of the positive electrode current collector is measured by the center line average surface. The roughness Ra is 0.05 to 6.3 μm Ra. Further, in the method for manufacturing a lithium secondary battery according to the second invention, a positive electrode plate and a negative electrode plate each composed of at least one metal foil body are wound via a separator to form a wound type internal electrode body. In order to derive a current from each end of the positive electrode plate and the negative electrode plate, a predetermined portion (connection portion) of each of a positive electrode current collecting member made of aluminum and a negative electrode current collecting member made of copper is used. Respectively, to manufacture a lithium secondary battery. When the end of the negative electrode plate is connected to the connection of the negative electrode current collector, the power density of the connection of the negative electrode current collector is 3 kW / mm. 2 The laser is melted by the above laser, and the connection portion of the negative electrode current collector is welded to the end of the negative electrode plate. Further, the surface roughness (connection surface) of the connection portion of the negative electrode current collector is measured by the center line average surface. The roughness Ra is 0.05 to 6.3 μm Ra. It is preferable that the requirements of the first invention and the second invention are simultaneously satisfied.
Here, the “power density” of the laser according to the present invention means that the power (kW) of the laser is determined by measuring the irradiation point of the laser at a predetermined position (connection portion) of the positive or negative electrode current collecting member. Spot area (mm 2 ) Means the value obtained. Further, the wound internal electrode body may be a laminated internal electrode body formed by laminating a positive electrode plate and a negative electrode plate each composed of at least one metal foil body via a separator. Further, the positive electrode current collector may be formed of an aluminum alloy, and the negative electrode current collector may be formed of a copper alloy. The center line average surface roughness Ra is a surface roughness defined in JIS B 0601 and ISO R 1101.
When the connection portion of the positive electrode current collector and the positive electrode plate and the connection portion of the negative electrode current collector and the negative electrode plate are respectively connected, the connection portion covers a wide area (for example, a wide area as soon as protruding from the connection portion). Irradiation with strong energy rays damages the positive electrode metal foil constituting the positive electrode plate and the negative electrode metal foil constituting the negative electrode plate, thereby deteriorating the yield, and even if not damaged, the finished state is poor. Therefore, it is necessary to irradiate energy rays or the like intensively to a required position with weak energy. However, if the energy is too weak, a portion to be melted does not melt, so a certain amount of energy is required. Therefore, in the first invention, the energy ray is a laser, the positive electrode current collecting member is aluminum, and the energy density of the laser for melting the aluminum and welding (the connection portion of) the positive electrode current collecting member to the positive electrode plate is welded. Is 5 kW / mm 2 As described above, in the second invention, the energy density of the laser for melting the copper and welding the negative electrode current collector to the negative electrode plate is set to 3 kW by using copper as the negative electrode current collector. / Mm 2 As described above, the positive electrode current collector or the negative electrode current collector can be reliably melted, and furthermore, the energy density of the laser can be optimized based on the lower limit of the energy density of these lasers. The positive electrode current collector or the negative electrode current collector can be effectively melted at a high density. This makes it possible to obtain a method for manufacturing a lithium secondary battery having excellent productivity without causing any damage to the positive electrode metal foil or the negative electrode metal foil. Further, when the requirements of the first invention and the second invention are simultaneously satisfied, both the positive electrode current collecting member and the negative electrode current collecting member can be reliably melted, and the positive electrode current collector can be effectively formed at a low energy density. Both the current collecting member and the negative electrode current collecting member can be melted.
The energy density of the laser for welding the (positive connection part) of the positive electrode current collector and the positive electrode plate is 5 kW / mm. 2 Smaller (when the requirements of the first invention are not satisfied), and the energy density of the laser for welding the negative electrode current collector to the negative electrode plate is 3 kW / mm. 2 When smaller (when the requirement of the second invention is not satisfied), the connection state is not good and the mechanical strength is insufficient.
When connecting (welding) the positive current collector to the positive electrode plate with the laser (first invention), and connecting the negative current collector to the negative electrode with the laser. In the case of (welding) (second invention), the surface roughness of the connection surface affects the connection. By setting the center line average surface roughness Ra to 0.05 to 6.3 μm Ra, the connection by the laser can be performed. Can be performed well.
Hereinafter, one embodiment of the method of manufacturing the lithium secondary battery of the first invention will be described. FIG. 1 is a perspective view schematically showing a method for connecting a positive electrode plate and a positive electrode current collector in one embodiment of the method for manufacturing a lithium secondary battery of the first invention. As shown in FIG. 1, in the method of manufacturing a lithium secondary battery according to the present embodiment, the connection between the positive electrode current collector 4A and the positive electrode plate 1A is made by connecting the positive electrode plate 1A made of at least one metal foil. The narrow end surface 2 of the end portion 15 and the connection surface 9 of the connection portion 5 of the positive electrode current collecting member 4A are arranged at predetermined positions, and the connection portion 5 is melted by a laser 11 having a predetermined power density to be connected. This is performed by welding the portion 5 and the end portion 15 of the positive electrode plate. At this time, a plurality of locations on the narrow end face 2 and the connection surface 9 are welded.
FIG. 2 is a perspective view schematically showing one example of a method of connecting a negative electrode plate and a negative electrode current collecting member in the method of manufacturing a lithium secondary battery according to the present embodiment. As shown in FIG. 2, in the method for manufacturing a lithium secondary battery according to the present embodiment, the connection between negative electrode current collector 4B and negative electrode plate 1B is made by connecting negative electrode plate 1B composed of at least one metal foil body. The vicinity of the end portion 15 is bent so that the side surface portion 13 facing the connection portion 5 side (connection surface 9 side) of the negative electrode current collecting member 4B and the connection surface 9 of the connection portion 5 of the negative electrode current collecting member 4B are fixed. It is preferable that the connection portion 5 is melted by the laser 11 having a predetermined power density, and the connection portion 5 is welded to the end portion 15 of the negative electrode plate. At this time, the connection surface 9 is welded to a plurality of locations on the side surface portion 13.
In the method of manufacturing a lithium secondary battery according to the present embodiment, as shown in FIG. 3, in addition to the above configuration, internal terminals 69A and 69B, external terminals 70A and 70B, and battery lids 71A and 71B are provided. An electrode lid is manufactured, and the positive electrode current collector 4A is connected to the positive electrode plate 1A (see FIG. 1) of the wound internal electrode body 61 by the above-described method, and the negative electrode current collector 4B is connected to the negative electrode plate 1B (see FIG. 2). Although connected, the positive electrode current collecting member 4A and the negative electrode current collecting member 4B are connected to the internal terminals 69A and 69B using the electrode lead members 72, respectively. At this time, it is preferable that the electrode lead member 72 is formed of the same kind of metal including the current collecting members 4A and 4B and the internal terminals 69A and 69B to be connected, and an alloy thereof. Specifically, since aluminum or an aluminum alloy is used for the positive electrode internal terminal 69A and the positive electrode current collecting member 4A, aluminum or an aluminum alloy is adopted for the positive electrode lead member, and the negative electrode internal terminal 69B and the negative electrode current collecting member are used. Since copper or copper alloy is used for 4B, it is preferable to use copper or copper alloy for the electrode lead member of the negative electrode.
In the method of manufacturing a lithium secondary battery according to the present embodiment, the wound internal electrode body 61 provided with the above-mentioned electrode cover is inserted into the battery case 73 and the vicinity of both ends of the battery case 73 is removed. A constricted portion is formed by constricting, and a lithium secondary battery 68 can be obtained by injecting an electrolytic solution. In FIG. 3, reference numeral 67 denotes a winding core, and reference numeral 75 denotes a pressure relief valve.
In the present embodiment, the current collectors 4A, 4B and the internal terminals 69A, 69B may be directly connected and energized without using the electrode lead members 72. In addition, the above-described electrode lid as a current deriving portion may be used for the positive electrode and the negative electrode, or may be used for either the positive electrode or the negative electrode.
In the present invention (first invention), as shown in FIG. 6, an external terminal is provided directly on the current collecting member 54 and formed so as to directly draw a current outside the battery. The current collecting member 54 may also be used as the electrode cover. FIG. 6 shows an example in which a cylindrical battery case 73 having one open end is used, and necking is formed on one end of the battery case 73. However, if the current collecting member 54 also serves as an electrode cover, The shape of the lithium secondary battery 68 is not particularly limited, and both ends of the battery case 73 may be constricted or both ends of the battery case 73 may not be constricted. FIG. 6 shows an example in which the pressure release holes 75 are formed on the positive electrode side, but pressure release holes may be formed on the negative electrode side. 6, reference numeral 61 denotes a wound internal electrode body, and reference numeral 67 denotes a winding core.
As shown in FIGS. 3 and 6, each electrode plate and current collecting members 4A, 4B (see FIG. 3), 54 (see FIG. 3) are provided at a portion where current is drawn from the internal electrode body (the wound internal electrode body 61). 6) is directly connected to derive the current, so that there is no need to use a current collecting tab as a conventional current deriving means, and thus a complicated current collecting tab mounting step is not required. By doing so, the productivity can be improved, and the space for the length of the current collecting tab can be omitted, so that the space saving can be improved.
In this embodiment, as shown in FIG. 7, the connecting portions 5 of the positive electrode current collecting member 4A are arranged in a row from the surface 4C of the positive electrode current collecting member 4A facing the positive electrode plate 1A toward the positive electrode plate 1A. A connecting surface 9 is formed at the tip end of the connecting portion 5 having a continuous shape, and the connecting surface 9 and the narrow end surface 2 of the end portion 15 of the positive electrode plate 1A are formed. It is preferable that the connection be made in a state of facing. Then, as shown in FIG. 7, when connecting the end portion 15 of the positive electrode plate 1A and the connecting portion 5 of the positive electrode current collecting member 4A, the convex connecting portion 5 is irradiated with the laser 11 to form the convex connecting portion. It is preferable that the portion 5 is melted and the convex connection portion 5 of the positive electrode current collector 4A and the end 15 of the positive electrode plate 1A are welded. Furthermore, it is preferable that the position where the connecting portion 5 is provided in the positive electrode current collecting member 4A be the distal end portion 6 of the positive electrode current collecting member 4A because the connection surface can be easily confirmed. In FIG. 7, reference numeral 12 denotes a flat portion, and the positive electrode current collecting member 4A has a structure having the connection portion 5 and the flat portion 12. As shown in FIG. 1, the convex connection portion protrudes from the surface 4C of the positive electrode current collector 4A facing the positive electrode plate 1A toward the positive electrode plate 1A, and the positive current collector 4A is A shape formed so as to extend in a direction extending outward is also included.
The convex shape of the convex connecting portion 5 of the positive electrode current collecting member 4A shown in FIG. 7 is not particularly limited, and the welding between the end 15 of the positive electrode plate 1A and the positive electrode current collecting member 4A is performed. In order to facilitate the connection, it is preferable that the connection surface 9 of the convex connection portion 5 and the narrow end surface 2 of the positive electrode metal foil body 1A be reliably contacted. For example, the connection portion 5 shown in FIG. Such a shape may be employed, and a preferable example is that the connection surface 9 of the convex connection portion 5 and the narrow end surface 2 of the positive electrode metal foil body 1A are in point contact with each other.
FIGS. 14 and 15 show specific examples of the shapes of the convex connecting portions 5 of the positive electrode current collecting member 4A and the negative electrode current collecting member 4B. The shape of each convex connecting portion 5 of the positive electrode current collecting member 4A and the negative electrode current collecting member 4B described later used in the lithium secondary battery of the present invention may be trapezoidal as shown in FIG. It may have a spire shape as shown in FIG. 14 and 15, L 1 Is the thickness of the flat portion 12, L 2 Indicates the thickness of the convex connection portion 5.
In the method of manufacturing a lithium secondary battery according to the present embodiment, as shown in FIGS. 14 and 15, a positive current collector 4A is formed into a shape having a convex connecting portion 5 and a flat portion 12 other than the connecting portion 5. And the thickness (L 2 ) And the thickness of the flat portion 12 (L 1 ) Is preferably 0.1 mm or more, more preferably 0.6 mm or more, and particularly preferably 0.8 mm or more. When the difference in thickness between the convex connecting portion 5 and the flat portion 12 is less than 0.1 mm, the shape characteristics of the convex connecting portion 5 are not exhibited, and the convex connecting portion 5 and the positive electrode This is not preferable because the contact state with the plate 1A becomes unstable. Further, in the present invention, the upper limit of the difference in thickness between the convex connection portion 5 and the flat portion 12 is not particularly limited, but may be appropriately set in view of the processing accuracy, strength, and the like of the positive electrode current collector. What is necessary is just 3 mm or less.
When pressing the positive electrode current collector against the positive electrode plate at the time of connection, from the viewpoint of preventing the positive electrode current collector from being deformed or damaged, the thickness of the flat portion of the positive electrode current collector 4A may be reduced. (L 1 ) Is preferably at least 0.4 mm, more preferably at least 0.5 mm, particularly preferably at least 0.6 mm. The upper limit of the thickness of the flat portion is not particularly limited, but may be appropriately set based on the strength and weight of the positive electrode current collector because the portion is not directly related to the welded portion. What is necessary is just 2 mm or less.
The thickness (L) of the convex connecting portion 5 of the positive electrode current collecting member 4A 2 ) Is preferably 0.6 mm or more, more preferably 0.7 mm or more, and particularly preferably 0.8 mm or more. As a result, the connection can be made stronger. The upper limit of the thickness of the convex connection portion 5 is not particularly limited, but may be set as appropriate from the limit of the power of the laser to be irradiated.
Regarding the shape of the laser-irradiated portion of the positive electrode current collector used in the lithium secondary battery of the present invention, the following shapes can be mentioned as preferred examples.
FIG. 7 shows an example in which the positive electrode current collector 4A having the convex connecting portion 5 at the front end 6 is used. In this case, the upper surface side (surface) of the positive electrode current collector 4A is used. By irradiating the laser 11 from the side opposite to 4C), the positive electrode current collector 4A and the end 15 of the positive electrode plate 1A can be welded and connected.
FIG. 9 shows an example in which a positive current collector 31A having a greater thickness is used for the convex connecting portion 33 than the positive current collector 4A shown in FIG. In addition to irradiating the laser 34 from the upper surface side of the current collecting member 31A, it is also possible to irradiate the laser 35 to the side surface of the convex connecting portion 33 formed at the tip portion 32 of the positive electrode current collecting member 31A. The current collecting member 31A and the end 15 of the positive electrode plate 1A can be connected by welding. In FIG. 9, reference numeral 2 denotes a narrow end face, and 3A denotes a normal line of a plane including the narrow end face.
FIG. 10 shows an example in which the plate-shaped positive current collector 41 is arranged so that its end surface is in contact with the end 15 of the positive electrode plate 1A. By irradiating the laser 42 from the side surface of the cathode 41, the cathode current collector 41 and the end 15 of the cathode plate 1A can be welded and connected. As described above, the lithium secondary battery of the present invention can also be manufactured by connecting the plate-shaped positive current collector 41 having no convex portion and the plurality of positive plates 1A as shown in FIG. Can be done. In FIG. 10, reference numeral 2 denotes a narrow end face, and 3A denotes a normal line of a plane including the narrow end face.
FIG. 11 shows an example in which a convex connecting portion 52 is provided at a predetermined position, not at the tip end of the positive electrode current collecting member 51A. In this case, the convex connecting portion 52 is provided. By irradiating the laser 53 to the rear surface of the provided positive electrode current collecting member 51A, the positive electrode current collecting member 51A can be connected to the end 15 of the positive electrode plate 1A. In FIG. 11, reference numeral 2 denotes a narrow end face.
On the other hand, in the present embodiment, as shown in FIG. 8, the connecting portion 5 of the negative electrode current collecting member 4B is connected from the surface 4D of the negative electrode current collecting member 4B facing the negative electrode plate 1B to the negative electrode plate 1B. And a connecting surface 9 is formed at the end of the convex connecting portion 5 and the vicinity of the end 15 of the negative electrode plate 1B is bent to form a connecting surface 9 at the end of the convex connecting portion 5. Is connected to the connection surface 9 of the negative electrode current collector 4B, and the side surface 13 near the end 15 of the negative electrode plate 1B is connected to the connection surface 9 (connection portion 5) of the negative electrode current collector 4B. Is preferred. Then, as shown in FIG. 8, when connecting the end portion 15 of the negative electrode plate 1B and the convex connection portion 5 of the negative electrode current collecting member 4B, the convex connection portion 5 is irradiated with the laser 11, It is preferable to melt the connection part 5 in a shape and weld the convex connection part 5 of the negative electrode current collecting member 4B and the end part 15 of the negative electrode plate 1B. Further, in the negative electrode current collecting member 4B, it is preferable that the position where the connecting portion 5 is provided is the distal end portion 6 of the negative electrode current collecting member 4B because the connection surface can be easily confirmed. In FIG. 8, 12 is a flat portion, L 1 Is the thickness of the flat portion 12, L 2 Indicates the thickness of the connection portion 5. The negative electrode current collecting member 4B has a structure having a connection portion 5 and a flat portion 12. Further, as shown in FIG. 2, the convex connection portion protrudes from the surface 4C of the negative electrode current collector 4B facing the negative electrode plate 1B toward the negative electrode plate 1B in a convex shape. A shape formed so as to extend in a direction extending outward is also included.
In the present embodiment, as shown in FIG. 8, when connecting the negative electrode plate 1B and the negative electrode current collecting member 4B, the vicinity of the end 15 is bent so that the side surface portion 13 is connected to the convex connection. The contact surface 9 of the portion 5 may be brought into close contact with the side surface portion 13 and the connection surface 9 may be brought into close contact with each other, for example, as shown in FIG. Is bent in the vicinity of the end 15 (FIG. 16A), and then the negative electrode current collecting member 4B is arranged on the side surface 13 (FIG. 16B). Also, as shown in FIG. 17, a method of pressing the negative electrode current collecting member 4B against the end portion 15 of the negative electrode plate 1B with an appropriate pressure, bending the vicinity of the end portion 15 and bringing the side surface portion 13 into close contact (FIG. ), (B), and (c)).
In the method of manufacturing a lithium secondary battery according to the present embodiment, when the side surface near the end of the negative electrode plate and the connection surface of the negative electrode current collector are connected, the side surface near the end of the negative electrode plate is connected. It is preferable that columnar crystals are formed in the direction from the portion toward the negative electrode current collector. Generally, in a weld metal, a molten metal grows (epitaxial growth) with the same crystal orientation on crystal grains of a base material (unmelted portion). The solid phase thus formed grows inside the weld bead (molten portion) as the heat source moves. This growth is easy to grow in the direction of the largest temperature gradient, and grows in a form extending almost in one direction in that direction. The crystal thus grown is called a columnar crystal.
The melted portion of the negative electrode current collector recrystallizes as it is cooled, but the heat of the molten portion rapidly diffuses through the negative electrode plate 1B. That is, it is considered that the temperature of the molten metal in the portion in close contact with the negative electrode plate decreases, and the interface between the negative electrode plate and the molten metal serves as a nucleus to easily form columnar crystals from the negative electrode plate toward the negative electrode current collector. Furthermore, in the present embodiment, since the side portion near the end portion of the negative electrode plate is in close contact with the negative electrode current collecting member without any gap and the contact state is good, columnar crystals are easily formed by the cooling effect through the negative electrode plate. State. As described above, by forming columnar crystals in the direction from the negative electrode plate to the negative electrode current collecting member at the connection portion between the negative electrode plate and the negative electrode current collecting member, the connection state between the negative electrode plate and the negative electrode current collecting member is good, Thus, a lithium secondary battery having high mechanical strength at the connection portion and excellent reliability can be obtained.
The shape of the convex connecting portion of the negative electrode current collector used in the method of manufacturing a lithium secondary battery according to the present embodiment is not particularly limited. Here, specific examples of the shape of the convex connection portion are shown in FIGS. As described above, the shape of the convex connecting portion 5 of the negative electrode current collecting member 4B used in the method for manufacturing a lithium secondary battery of the present embodiment may be a trapezoidal shape as shown in FIG. It may have a spire shape as shown in FIG.
In the lithium secondary battery of the present embodiment, as shown in FIGS. 14 and 15, the negative electrode current collector 4B has a shape having a convex connecting portion 5 and a flat portion 12 other than the convex connecting portion 5. Thickness (L 2 ) And the thickness of the flat portion 12 (L 1 ) Is preferably 0.1 mm or more, more preferably 0.6 mm or more, and particularly preferably 0.8 mm or more. When the difference in thickness between the convex connecting portion 5 and the flat portion 12 is less than 0.1 mm, the shape characteristics of the convex connecting portion 5 are not exhibited, and the convex connecting portion 5 and the negative electrode This is not preferable because the contact state with the plate 1B becomes unstable. The upper limit of the difference in thickness between the convex connection portion 5 and the flat portion 12 of the negative electrode current collecting member 4B is not particularly limited, but may be set as appropriate from the processing accuracy and strength of the negative electrode current collecting member. For example, it may be 3 mm or less.
When the negative electrode current collector is pressed against the negative electrode plate at the time of connection, from the viewpoint of preventing the negative electrode current collector from being deformed or damaged, the thickness of the flat portion (L 1 ) Is preferably at least 0.2 mm, more preferably at least 0.3 mm, particularly preferably at least 0.4 mm. The upper limit of the thickness of the flat portion is not particularly limited, but may be appropriately set based on the strength and weight of the negative electrode current collector because the portion is not directly related to the welded portion. The following may be sufficient.
The thickness (L) of the convex connection portion of the negative electrode current collecting member 4B 2 ) Is preferably at least 0.4 mm, more preferably at least 0.5 mm, particularly preferably at least 0.6 mm. As a result, the connection can be made stronger. The upper limit of the thickness of the convex connection portion is not particularly limited, but may be set as appropriate from the limit of the power of the laser to be irradiated.
Regarding the shape of the laser irradiation portion (connection portion) of the negative electrode current collector used in the lithium secondary battery of the present embodiment, the following shapes can be mentioned as preferred examples.
FIG. 8 shows an example of the negative electrode current collecting member 4B having the convex connecting portion 5 at the tip end portion 6. In this case, the laser 11 is applied from the upper surface side of the negative electrode current collecting member 4B. By irradiating, the negative electrode current collecting member 4B and the end 15 of the negative electrode plate 1B can be welded and connected.
FIG. 12 shows an example of a negative electrode current collector 31B having a thicker connecting portion 33 formed at the tip end portion 32 than the negative electrode current collector 4B of FIG. In this case, by irradiating the laser 34 from the upper surface side of the negative electrode current collecting member 31B, the negative electrode current collecting member 31B and the end portion 15 (side surface portion 13) of the negative electrode plate 1B can be welded and connected. 3B indicates a normal line of a surface including the side surface portion 13.
FIG. 13 shows an example in which a convex connecting portion 52 is provided at a predetermined position, not at the tip end of the negative electrode current collecting member 51B. In this case, the convex connecting portion 52 is formed. By irradiating the laser 53 to the back surface of the provided negative electrode current collecting member 51B, the negative electrode current collecting member 51B can be connected to the side surface portion 13 near the end 15 of the negative electrode plate 1B. In FIG. 13, reference numeral 12 denotes a flat portion.
In this embodiment, when aluminum or aluminum alloy of the same material as the positive electrode current collector is used for the positive electrode plate and copper or copper alloy of the same material as the negative electrode current collector is used for the negative electrode plate, Since the metal plate (metal foil) and the current collecting member are made of the same kind of metal, the metal plate (metal foil) and the current collecting member are better welded to each other, and the mechanical strength of the current lead-out portion is improved. Can be strengthened. In this case, the thickness of the positive electrode plate (metal foil body) made of aluminum or aluminum alloy is preferably 15 to 25 μm, and the thickness of the negative electrode plate (metal foil body) made of copper or copper alloy is 7 to 25 μm. It is preferably 15 μm. In the batteries shown in FIGS. 3 and 6, an aluminum foil having a thickness of 20 μm and a copper foil having a thickness of 10 μm are used.
As shown in FIGS. 5 (a) and 5 (e), at least one of the positive electrode current collecting member 4A and the negative electrode current collecting member 4B used in this embodiment is a cross-shaped plate-like member. 5 (b) and 5 (f), a Y-shaped plate member, or an I-shaped plate member as shown in FIGS. 5 (c) and 5 (g), or FIGS. As shown in FIG. 5 (d) and FIG. 5 (h), it is preferable to use a disk-shaped member having a cutout in a part. As a result, the connection portion can be easily inspected and the weight can be reduced, and the electrolyte can easily flow around when the electrolyte is filled. In FIG. 4, 5 indicates a connection portion, 61 indicates a wound internal electrode body, and 73 indicates a battery case.
In the method of manufacturing a lithium secondary battery according to the present embodiment, when connecting the positive current collector to the positive electrode plate, a laser is applied to the convex connection of the positive current collector to irradiate the convex connection. For example, as shown in FIG. 7, the laser 11 is irradiated with the laser 11 at an angle θ (0 ° <θ ≦ 90 °) with respect to a normal 3A to the surface including the narrow end face 2 of the end 15 of the positive electrode plate 1A. ), The irradiation is preferably performed at an angle θ (5 ° ≦ θ ≦ 80 °), and more preferably at an angle θ (10 ° ≦ θ ≦ 60 °). Irradiation at an angle θ (15 ° ≦ θ ≦ 45 °) is particularly preferable. In addition, it is preferable that the laser 11 is focused on the surface of the convex connection portion 5 of the positive electrode current collecting member 4A or in the vicinity thereof, and it is preferable that the laser 11 is not directly irradiated on the positive electrode plate 1A.
Further, the positive electrode current collecting member 4A is arranged so that the convex connecting portion 5 thereof intersects the narrow end face 2 substantially perpendicularly, and the laser 11 intersects the narrow end face 2 substantially perpendicularly. As described above, it is preferable to perform scanning by the laser generator, that is, scan and irradiate the convex connection portion 7 of the positive electrode current collector 4A. At this time, the above-described laser 11 is irradiated to the convex connecting portion 5 at an angle θ (0 ° <θ ≦ 90 °) with respect to a normal 3A to the surface including the narrow end face 2 of the positive electrode plate 1A. In addition, it is preferable that the laser 11 is irradiated on the convex connection portion 5 having a substantially perpendicular angle with respect to a line that intersects substantially perpendicularly with the narrow end face 2. As a result, as shown in FIG. 1, the positive electrode plate 1A and the melt of the positive electrode current collecting member 4A can be welded to each other to connect the positive electrode plate 1A and the positive electrode current collecting member 4A without using a brazing material. I can do it. Further, at least one positive electrode plate 1A can be connected to the positive electrode current collecting member 4A by a single irradiation. Further, it is possible to melt and connect only the positive electrode plate 1A and the positive electrode current collecting member 4A by melting only a predetermined portion (convex connecting portion 5) of the positive electrode current collecting member 4A without damaging the positive electrode plate 1A. For this reason, the mechanical strength of the connection can be increased.
[0097] The term "intersects substantially perpendicularly to the narrow end face" in the present embodiment means that the positive (negative) electrode corresponding to the portion connected to the connection portion of the positive (negative) current collecting member. This means that all of the narrow end faces at the ends of the plate intersect substantially perpendicularly.
In the method of manufacturing a lithium secondary battery according to the present embodiment, when connecting the negative electrode current collecting member and the negative electrode plate, the convex connecting portion of the negative electrode current collecting member is irradiated with a laser to project the convex connecting portion. For example, as shown in FIG. 8, the laser 11 is applied to a surface of the negative electrode plate 1B formed so as to face the connecting surface 9 of the negative electrode current collecting member 4B, including a side surface portion 13 near the end portion 15 as shown in FIG. With respect to the line 3B, it is preferable to irradiate the convex connection portion 5 at an angle θ (0 ° ≦ θ ≦ 30 °), and it is more preferable to irradiate the line 3B at an angle θ (0 ° ≦ θ ≦ 10 °). Irradiation at an angle θ (0 ° ≦ θ ≦ 5 °) is particularly preferred. Further, it is preferable that the laser 11 is focused on the surface of the convex connection portion 5 of the negative electrode current collecting member 4B or in the vicinity thereof, and it is preferable that the laser 11 is not directly irradiated on the negative electrode metal foil 1B.
Further, the negative electrode current collecting member 4B is arranged so that the convex connection portion 5 thereof intersects the side surface 13 substantially perpendicularly, and the laser 11 is arranged so that the laser 11 intersects the side surface approximately perpendicularly. It is preferable to scan with a laser generator, that is, scan and irradiate the convex connection portion 5 of the negative electrode current collector 4. At this time, the above-described laser 11 is applied to the convex connection portion 5 at an angle θ (0 ° ≦ θ ≦ 30 °) with respect to a normal 3B to the surface including the side surface portion 13 of the negative electrode plate 1B. In addition, it is preferable to irradiate the laser 11 to the convex connection portion 5 having a substantially perpendicular angle with respect to a line substantially perpendicular to the side surface portion 13. Thus, the negative electrode plate 1B and the melt of the negative electrode current collecting member 4B can be welded to each other to connect the negative electrode plate 1B and the negative electrode current collecting member 4B without the need for a brazing material as shown in FIG. I can do it. In addition, at least one negative electrode plate 1B can be connected to the negative electrode current collecting member 4B by a single irradiation. Furthermore, it is possible to melt and connect the negative electrode plate 1B and the negative electrode current collecting member 4B by melting only a predetermined portion (the convex connection portion 5) of the negative electrode current collecting member 4B without damaging the negative electrode plate 1B. For this reason, the mechanical strength of the connection can be increased. Note that “intersects substantially perpendicularly to the side surface” means that all of the plurality of locations connected to the connection portion 5 intersect approximately vertically in the side surface portion 13 of the end portion 15 of the negative electrode plate 1B. ing.
In the method of manufacturing a lithium secondary battery according to the present embodiment, when the convex connecting portion of the negative electrode current collector is irradiated with a laser to melt the convex connecting portion, the convex connecting portion is formed. Part thickness L 2 (Mm), the power density of the laser is E (kW / mm 2 ), It is preferable to satisfy the following expression (5). The power density of the laser means the power density at the irradiation point. By irradiating the laser under the condition satisfying the following formula (5), damage to the negative electrode plate is suppressed, and the mechanical strength of the connection portion between the negative electrode current collector and the negative electrode plate is increased. .
[0101]
(Equation 5)
L 2 ≦ E / 7 (5)
It is preferable to satisfy the following expressions (6) and (7) from the viewpoint of further suppressing damage to the negative electrode plate and increasing the mechanical strength of the connection portion.
[0103]
(Equation 6)
L 2 ≦ E / 9 (6)
[0104]
(Equation 7)
L 2 ≦ E / 10 (7)
In the method of manufacturing a lithium secondary battery according to the present embodiment, it is preferable that the spot diameter at the laser irradiation point is 1 mm or less. This suppresses laser irradiation to unnecessary portions, and in particular, it is possible to suppress damage to the negative electrode plate, so that a favorable connection state can be obtained. In the method for manufacturing a lithium secondary battery according to the present invention, it is preferable that at least one of the adjacent positive electrode plates and the adjacent negative electrode plates be arranged while maintaining a gap.
In this embodiment, for example, the laser 11 shown in FIGS. 7 and 8 is preferably a continuous wave. Thereby, since the energy can be concentrated and irradiated on the surface of the convex connection portion 5, the convex connection portion 5 can be efficiently melted, and the positive electrode plate 1A or the negative electrode plate 1B can be melted. Damage can be suppressed. In addition, among lasers, the YAG laser can narrow the focus better, and the energy density becomes smaller at the position of the positive electrode plate 1A or the negative electrode plate 1B arranged at a part out of focus, and the positive electrode plate 1A or It is particularly preferable because damage to the negative electrode plate 1B can be more effectively suppressed.
In the method of manufacturing a lithium secondary battery according to the present embodiment, for example, it is preferable to irradiate the laser 11 shown in FIG. 7 using a laser generator capable of continuous irradiation. Irradiation is preferably performed using a laser generator capable of scanning a plane parallel to the plane including the narrow end face 2. In addition, the scanning speed of the laser to be irradiated is preferably 0.1 to 100 m / min, more preferably 1 to 30 m / min, and particularly preferably 2 to 10 m / min. When the connecting portion 5 of the positive electrode current collecting member 4A is convex, it is preferable that the laser 11 is scanned and irradiated along the convex connecting portion 5 by a laser generator. Further, in the present invention, a plurality of positive electrode current collecting members 4A are prepared in accordance with the number of the arranged positive electrode plates 1A, and the plurality of positive electrode current collecting members 4A are connected to each other so that their convex connecting portions 5 have narrow end faces. It is preferable to arrange them continuously so as to intersect approximately perpendicularly with 2. Thus, a plurality of positive plates 1A can be connected by a single irradiation.
On the other hand, in the method of manufacturing the lithium secondary battery of the present embodiment, for example, it is preferable to irradiate the laser 11 shown in FIG. 8 using a laser generator capable of continuous irradiation. Irradiation is preferably performed using a laser generator capable of scanning a surface parallel to the surface including the side surface portion 13. When the connecting portion 5 of the negative electrode current collecting member 4B is convex, it is preferable that the laser 11 is scanned and irradiated by the laser generator along the convex connecting portion 5. Further, in the present invention, a plurality of negative electrode current collecting members 4B are prepared according to the number of the arranged negative electrode plates 1B, and the plurality of negative electrode current collecting members 4B are connected to the convex connection portions 5 by the side portions 13. It is preferable to arrange them continuously so as to intersect approximately vertically. Thus, a plurality of negative electrode plates 1B can be connected by a single irradiation.
In the method of manufacturing a lithium secondary battery according to the first aspect of the invention, a connection auxiliary material (connecting material) such as a brazing material is required when connecting the connecting portion of the positive electrode current collector to the end of the positive electrode plate. No, but of course you can. In that case, a connecting material that assists the connection between the connection part of the positive electrode current collector and the end of the positive electrode plate is applied to at least one of the end part of the positive electrode plate and the connection part of the positive electrode current collector, Or, by sandwiching between the end portion of the positive electrode plate and the connection portion of the positive electrode current collector, and irradiating a laser to the connection portion and the connection material of the positive electrode current collector, the connection portion and the connection material of the positive electrode current collection member It is preferable that the connecting portion and the connecting material of the positive electrode current collecting member be melted and welded to an end portion of the positive electrode plate.
In the method of manufacturing a lithium secondary battery according to the first invention, when connecting the negative electrode current collector to the negative electrode plate, a connection auxiliary material (connecting material) such as a brazing material is not required. You can use it. In that case, a connection material for assisting connection between the connection portion of the negative electrode current collector and the end of the negative electrode plate is applied to at least one of the end portion of the negative electrode plate and the connection portion of the negative electrode current collector, Or, by sandwiching between the end portion of the negative electrode plate and the connection portion of the negative electrode current collecting member, and irradiating the laser to the connection portion and the connection material of the negative electrode current collection member, the connection portion and the connection material of the negative electrode current collection member It is preferable that the connection portion and the connection material of the negative electrode current collecting member are melted and welded to the end portion of the negative electrode plate.
Next, a method for manufacturing the lithium secondary battery of the second invention will be described. As described above, in the method for manufacturing a lithium secondary battery according to the second invention, a positive electrode plate and a negative electrode plate each composed of at least one metal foil are wound via a separator to form a wound internal electrode. Are formed, and in order to derive a current from the ends of the positive electrode plate and the negative electrode plate, predetermined positions of each of a positive electrode current collector made of aluminum and a negative electrode current collector made of copper ( Connection part) to manufacture a lithium secondary battery. When the end of the negative electrode plate is connected to the connection part of the negative electrode current collector, the connection part of the negative electrode current collector has a lower power density. 3 kW / mm 2 The laser is melted by the above laser, and the connection portion of the negative electrode current collector is welded to the end of the negative electrode plate. Further, the surface roughness (connection surface) of the connection portion of the negative electrode current collector is measured by the center line average surface. The roughness Ra is 0.05 to 6.3 μm Ra.
In one embodiment of the method of manufacturing the lithium secondary battery of the second invention, as in the case of the above-described first embodiment, as shown in FIG. The connection between the negative electrode plate 1B and the negative electrode plate 1B is made by bending the vicinity of the end portion 15 of the negative electrode plate 1B formed of at least one metal foil to the connection portion 5 side (connection surface 9 side) of the negative electrode current collecting member 4B. Are arranged in a predetermined position, and the connection portion 5 is melted by a laser 11 having a predetermined power density, and the connection portion 5 is formed. And the end portion 15 of the negative electrode plate. At this time, the connection surface 9 is welded to a plurality of locations on the side surface portion 13.
In the present embodiment, as in the case of the above-described first embodiment, as shown in FIG. 8, the connecting portion 5 of the negative electrode current collecting member 4B is connected to the negative electrode current collecting member 4B. A connecting surface 9 is formed at the tip of the convex connecting portion 5 to form a convex shape that continuously protrudes in a row from the surface 4D facing the negative electrode plate 1B toward the negative electrode plate 1B. 15 is bent so that the side portion 13 near the end portion 15 of the negative electrode plate 1B faces the connection surface 9 of the negative electrode current collecting member 4B. It is preferable to connect the connection surface 9 (connection portion 5) of the member 4B. Then, as shown in FIG. 8, when connecting the end portion 15 of the negative electrode plate 1B and the convex connection portion 5 of the negative electrode current collecting member 4B, the convex connection portion 5 is irradiated with the laser 11, It is preferable to melt the connection part 5 in a shape and weld the convex connection part 5 of the negative electrode current collecting member 4B and the end part 15 of the negative electrode plate 1B. Further, in the negative electrode current collecting member 4B, it is preferable that the position where the connecting portion 5 is provided is the distal end portion 6 of the negative electrode current collecting member 4B because the connection surface can be easily confirmed. In FIG. 8, 12 is a flat portion, L 1 Is the thickness of the flat portion 12, L 2 Indicates the thickness of the connection portion 5. The negative electrode current collecting member 4B has a structure having a connection portion 5 and a flat portion 12. Further, as shown in FIG. 2, the convex connection portion protrudes from the surface 4C of the negative electrode current collector 4B facing the negative electrode plate 1B toward the negative electrode plate 1B in a convex shape. A shape formed so as to extend in a direction extending outward is also included.
In the present embodiment, as in the case of the above-described first embodiment, as shown in FIG. The side surface portion 13 and the connection surface 9 of the convex connection portion 5 may be brought into close contact with each other by bending the vicinity of the connection portion 15, and the close contact between the side surface portion 13 and the connection surface 9 is made in the first manner described above. The invention can be carried out by the same method as the “method of bringing the side surface portion (of the negative electrode plate) into close contact with the connection surface (of the negative electrode current collector)” (described with reference to FIGS. 16 and 17).
In the method of manufacturing a lithium secondary battery according to the present embodiment, when the side surface near the end of the negative electrode plate is connected to the connection surface of the negative electrode current collecting member, the above-described first embodiment of the present invention is used. As in the case of “when connecting the side surface near the end of the negative electrode plate and the connection surface of the negative electrode current collector” in the form, columnar crystals are formed from the side surface near the end of the negative electrode plate toward the negative electrode current collector. Preferably, it is formed.
As in the case of the first embodiment, columnar crystals are formed in the connecting portion between the negative electrode plate and the negative electrode current collecting member in the direction from the negative electrode plate to the negative electrode current collecting member. Accordingly, a lithium secondary battery in which the connection state between the negative electrode plate and the negative electrode current collecting member is good, that is, the connection portion has high mechanical strength and excellent reliability.
The shape of the convex connecting portion of the negative electrode current collector used in the method of manufacturing a lithium secondary battery of the present embodiment is the same as that of the above-described first embodiment of the present invention. Like the “shape of the convex connection portion”, there is no particular limitation.
In the lithium secondary battery of the present embodiment, similarly to the case of the above-described first embodiment, as shown in FIGS. 14 and 15, the negative electrode current collector 4B has a convex connection. Part 5 and the other flat part 12, and the thickness (L 2 ) And the thickness of the flat portion 12 (L 1 ) Is preferably 0.1 mm or more, more preferably 0.6 mm or more, and particularly preferably 0.8 mm or more. When the difference in thickness between the convex connecting portion 5 and the flat portion 12 is less than 0.1 mm, the shape characteristics of the convex connecting portion 5 are not exhibited, and the convex connecting portion 5 and the negative electrode This is not preferable because the contact state with the plate 1B becomes unstable. The upper limit of the difference in thickness between the convex connection portion 5 and the flat portion 12 of the negative electrode current collecting member 4B is not particularly limited, but may be set as appropriate from the processing accuracy and strength of the negative electrode current collecting member. For example, it may be 3 mm or less.
When pressing the negative electrode current collector against the negative electrode plate during connection, from the viewpoint of preventing the negative electrode current collector from being deformed or damaged, the thickness of the flat portion (L 1 ) Is preferably at least 0.2 mm, more preferably at least 0.3 mm, particularly preferably at least 0.4 mm. The upper limit of the thickness of the flat portion is not particularly limited, but may be appropriately set based on the strength and weight of the negative electrode current collector because the portion is not directly related to the welded portion. The following may be sufficient.
The thickness (L) of the convex connecting portion of the negative electrode current collecting member 4B 2 ) Is preferably at least 0.4 mm, more preferably at least 0.5 mm, particularly preferably at least 0.6 mm. As a result, the connection can be made stronger. The upper limit of the thickness of the convex connection portion is not particularly limited, but may be set as appropriate from the limit of the power of the laser to be irradiated.
The shape of the laser irradiation portion (connection portion) of the negative electrode current collector used in the lithium secondary battery of the present embodiment has been described in the first embodiment of the present invention with reference to FIGS. A shape similar to the shape can be mentioned as a preferable example.
In this embodiment, as in the case of the first embodiment, aluminum or aluminum alloy of the same material as the positive electrode current collector is used for the positive electrode plate, and the negative electrode current collector is used for the negative electrode plate. When copper or a copper alloy of the same material as the current member is used, the metal plate (metal foil) and the current collecting member are composed of the same kind of metal. The current collecting member is welded better, and the mechanical strength of the current lead-out portion can be increased. In this case, the thickness of the positive electrode plate (metal foil body) made of aluminum or aluminum alloy is preferably 15 to 25 μm, and the thickness of the negative electrode plate (metal foil body) made of copper or copper alloy is 7 to 25 μm. It is preferably 15 μm.
In this embodiment, as in the case of the above-described first embodiment, as shown in FIGS. 5A and 5E, the negative electrode current collector 4B is It is preferable to form a letter-shaped plate-like member. Further, the negative electrode current collecting member 4B may be a Y-shaped plate-shaped member as shown in FIGS. 5 (b) and 5 (f), or as shown in FIGS. 5 (c) and 5 (g). It is preferable that the negative electrode current collecting member 4B be an I-shaped plate-shaped member. Further, as shown in FIGS. 4, 5D, and 5H, it is preferable that the negative electrode current collecting member 4B is a disk-shaped member having a cutout in a part. As a result, the connection portion can be easily inspected and the weight can be reduced, and the electrolyte can easily flow around when the electrolyte is filled.
In the method of manufacturing a lithium secondary battery according to the present embodiment, when connecting the negative electrode current collector to the negative electrode plate, the convex connection portion of the negative electrode current collector is irradiated with a laser to form the convex connection. When dissolving the portion, the laser 11 was formed so as to face the connection surface 9 of the negative electrode current collecting member 4B, for example, as shown in FIG. 8, as in the case of the above-described first embodiment of the invention. It is preferable to irradiate the convex connecting portion 5 at an angle θ (0 ° ≦ θ ≦ 30 °) with respect to a normal line 3B of the surface including the side surface portion 13 near the end portion 15 of the negative electrode plate 1B. (0 ° ≦ θ ≦ 10 °), and more preferably, at an angle θ (0 ° ≦ θ ≦ 5 °). Further, it is preferable that the laser 11 is focused on the surface of the convex connection portion 5 of the negative electrode current collecting member 4B or in the vicinity thereof, and it is preferable that the laser 11 is not directly irradiated on the negative electrode metal foil 1B.
Further, as in the case of the above-described first embodiment, the negative electrode current collecting member 4B is arranged so that the convex connection portion 5 thereof intersects the side surface portion 13 substantially perpendicularly. The laser 11 is preferably scanned by a laser generator so as to intersect the side surface 13 substantially perpendicularly, that is, by scanning the convex connecting portion 5 of the negative electrode current collecting member 4 for irradiation. At this time, the above-described laser 11 is applied to the convex connection portion 5 at an angle θ (0 ° ≦ θ ≦ 30 °) with respect to a normal 3B to the surface including the side surface portion 13 of the negative electrode plate 1B. In addition, it is preferable to irradiate the laser 11 to the convex connection portion 5 having a substantially perpendicular angle with respect to a line substantially perpendicular to the side surface portion 13. Thus, the negative electrode plate 1B and the melt of the negative electrode current collecting member 4B can be welded to each other to connect the negative electrode plate 1B and the negative electrode current collecting member 4B without the need for a brazing material as shown in FIG. I can do it. In addition, at least one negative electrode plate 1B can be connected to the negative electrode current collecting member 4B by a single irradiation. Furthermore, it is possible to melt and connect the negative electrode plate 1B and the negative electrode current collecting member 4B by melting only a predetermined portion (the convex connection portion 5) of the negative electrode current collecting member 4B without damaging the negative electrode plate 1B. For this reason, the mechanical strength of the connection can be increased.
In the method of manufacturing a lithium secondary battery according to the present embodiment, when the convex connecting portion of the negative electrode current collector is irradiated with laser to melt the convex connecting portion, the convex connecting portion is melted. Part thickness L 2 (Mm), the power density of the laser is E (kW / mm 2 ), It is preferable to satisfy the following expression (8). The power density of the laser means the power density at the irradiation point. By irradiating the laser under the condition satisfying the following formula (8), damage to the negative electrode plate is suppressed, and the mechanical strength of the connection portion between the negative electrode current collector and the negative electrode plate is increased. .
[0127]
(Equation 8)
L 2 ≦ E / 7 (8)
From the viewpoint of further suppressing damage to the negative electrode plate and increasing the mechanical strength of the connection portion, it is preferable that the following expressions (9) and (10) are satisfied.
[0129]
(Equation 9)
L 2 ≦ E / 9 (9)
[0130]
(Equation 10)
L 2 ≦ E / 10 (10)
In the method of manufacturing a lithium secondary battery according to the present embodiment, it is preferable that the spot diameter at the laser irradiation point is 1 mm or less. This suppresses laser irradiation to unnecessary portions, and in particular, it is possible to suppress damage to the negative electrode plate, so that a favorable connection state can be obtained. In the method for manufacturing a lithium secondary battery according to the present invention, it is preferable that at least one of the adjacent positive electrode plates and the adjacent negative electrode plates be arranged while maintaining a gap.
In the present embodiment, for example, as in the case of the above-described first embodiment, the laser 11 shown in FIG. 8 is preferably a continuous wave. Thereby, since the energy can be concentrated and irradiated on the surface of the convex connection portion 5, the convex connection portion 5 can be efficiently melted, and the damage of the negative electrode plate 1B can be suppressed. Can be done. Among the lasers, the YAG laser can narrow the focus better, and the energy density becomes smaller at the position of the negative electrode plate 1B located at a part out of focus, thereby better suppressing the damage of the negative electrode plate 1B. It is particularly preferable because it can be used.
On the other hand, in the method of manufacturing a lithium secondary battery according to the present embodiment, for example, the laser 11 shown in FIG. Irradiation is preferably performed using a laser generator, and it is preferable to irradiate the laser 11 using a laser generator capable of scanning a surface parallel to a surface including the side surface portion 13. When the connecting portion 5 of the negative electrode current collecting member 4B is convex, it is preferable that the laser 11 is scanned and irradiated by the laser generator along the convex connecting portion 5. Further, in the present invention, a plurality of negative electrode current collecting members 4B are prepared according to the number of the arranged negative electrode plates 1B, and the plurality of negative electrode current collecting members 4B are connected to the convex connection portions 5 by the side portions 13. It is preferable to arrange them continuously so as to intersect approximately vertically. Thus, a plurality of negative electrode plates 1B can be connected by a single irradiation.
In the method for manufacturing a lithium secondary battery according to the second invention, when connecting the negative electrode current collector to the negative electrode plate, a connection auxiliary material (connecting material) such as a brazing material is not required, but it is needless to say. You can use it. In that case, a connection material for assisting connection between the connection portion of the negative electrode current collector and the end of the negative electrode plate is applied to at least one of the end portion of the negative electrode plate and the connection portion of the negative electrode current collector, Or, by sandwiching between the end portion of the negative electrode plate and the connection portion of the negative electrode current collecting member, and irradiating the laser to the connection portion and the connection material of the negative electrode current collection member, the connection portion and the connection material of the negative electrode current collection member It is preferable that the connection portion and the connection material of the negative electrode current collecting member are melted and welded to the end portion of the negative electrode plate.
In the method of manufacturing the lithium secondary battery of this embodiment, as shown in FIG. 3, internal terminals 69A and 69B and external terminals 70A , 70B and an electrode lid having battery lids 71A, 71B, a positive current collector 4A is connected to the positive electrode 1A of the wound internal electrode body 61, and a negative current collector 4B is connected to the negative electrode 1B. Preferably, the positive electrode current collecting member 4A and the negative electrode current collecting member 4B are connected to the internal terminals 69A and 69B using the electrode lead members 72, respectively.
Further, in the second invention, as in the case of the first embodiment described above, as shown in FIG. The current collecting member 54 may also be used as an electrode cover.
In one embodiment of the second invention described above, except for the above-described conditions, the respective conditions relating to the positive electrode plate, the positive electrode current collector, the connection method thereof, and the method of manufacturing the lithium secondary battery are the same as those of the first embodiment. It is preferable to make the same as the embodiment of the present invention.
The first and second inventions described above are preferably used for a wound or laminated internal electrode body, and are particularly preferably used for those having a capacity of 2 Ah or more. Can be There are no particular restrictions on the use of batteries, but engines are used as high-capacity on-board batteries, which are designed to connect batteries in series and produce a large output and require a large amount of batteries to save space. For start-up, it can be particularly suitably used for driving a motor of an electric vehicle or a hybrid electric vehicle.
[0139]
EXAMPLES Hereinafter, the present invention (first and second inventions) will be described specifically with reference to examples, but the present invention is not limited to these examples.
[0140]
(Examples 1 to 9, Comparative Examples 1 and 2)
A continuous wave YAG laser was used as a laser, and an aluminum square plate having a length of 50 mm, a width of 100 mm and a thickness of 10 mm was used as a sample, and a melting test (melt volume measurement) of the aluminum square plate was performed with the YAG laser. As shown in Table 1, the energy density (laser power density) at the irradiation point of the YAG laser was 2 to 12 (kW / mm). 2 ) Are employed (Examples 1 to 9, Comparative Examples 1 and 2), and the scanning speed (m / min) and the state of the connection surface are changed at each laser power density as shown in Table 1. Then, the molten volume of the aluminum square plate (unit: mm 3 / S) was measured. Table 1 shows the results.
HAAS HLD3504 was used as the YAG laser. The laser was incident on the sample at right angles.
In the surface of the sample, the standard surface refers to a surface having a surface roughness of 0.41 μm Ra as a center line average surface roughness Ra, and the mirror surface refers to a surface having a center line average surface roughness Ra as follows: The surface of 0.06 μm Ra is referred to as an oxidized surface, and the surface of aluminum is oxidized to have a surface roughness of 6.18 μm as a center line average surface roughness Ra.
The center line average surface roughness Ra was measured by the following method.
The measurement was carried out using Taylor Hobson's Form Talysurf S5 in accordance with JIS B 0601 and ISO R 1101.
[0145]
(Examples 10 to 18, Comparative Examples 3 and 4)
Except for using a copper square plate having a length of 50 mm, a width of 100 mm, and a thickness of 10 mm as a sample, the molten volume of the copper square plate (unit: mm 3 / S) was measured. Table 2 shows the results.
[0146]
[Table 1]
Figure 2004220953
[0147]
[Table 2]
Figure 2004220953
As described above, when the aluminum square plate is melted by the YAG laser, the standard surface, the mirror surface and the oxidized surface are each 5 kW / mm. 2 It can be seen that the above power density is required.
When the copper square plate is melted by the YAG laser, the standard surface, the mirror surface, and the oxidized surface are each 3 kW / mm. 2 It can be seen that the above power density is required.
Thus, when the connection portion of the positive electrode current collector made of aluminum or an aluminum alloy is melted by a laser and welded (connected) to the positive electrode plate, 5 kW / mm 2 It can be seen that the above power density is required. In addition, when the connection portion of the negative electrode current collector made of copper or copper gold is melted with a laser and welded (connected) to the negative electrode plate, 3 kW / mm 2 It can be seen that the above power density is required. The surface roughness of the connection surface is 0.05 to 6.3 μm Ra as the center line average surface roughness Ra. Based on these conditions, by performing the welding with a laser having a low power density, damage to the positive electrode plate and the negative electrode plate can be prevented, so that the yield can be improved and the finished state can be improved.
[0151]
As described above, according to the present invention, an arrangement is employed in which the end of each electrode plate is directly connected to the current collecting member to derive a current from the internal electrode body. When connecting the current collecting member, the surface roughness of each connection surface is set to a predetermined range, and a laser having a predetermined energy density is used to weld each electrode plate and the current collecting member, thereby improving productivity. It is possible to provide a method of manufacturing a lithium secondary battery having excellent characteristics.
[Brief description of the drawings]
FIG. 1 is a perspective view schematically showing one embodiment of connection between a positive electrode plate and a positive electrode current collector in a method for manufacturing a lithium secondary battery of the first invention.
FIG. 2 is a perspective view schematically showing one embodiment of a connection between a negative electrode plate and a negative electrode current collecting member in the method for producing a lithium secondary battery according to the first and second inventions.
FIG. 3 is a cross-sectional view showing one embodiment of a lithium secondary battery obtained by the method for manufacturing a lithium secondary battery according to the first invention and the second invention.
FIG. 4 is a perspective view showing a wound electrode body and a positive electrode current collector in the method for manufacturing a lithium secondary battery according to the first and second inventions.
FIG. 5 is a schematic view showing an example of a current collecting member used in the method for manufacturing a lithium secondary battery according to the first invention and the second invention.
FIG. 6 is a cross-sectional view showing another embodiment of the lithium secondary battery obtained by the method for manufacturing a lithium secondary battery according to the first invention and the second invention.
FIG. 7 is a perspective view schematically showing a method for welding a positive electrode current collector and a positive electrode plate by laser in the method of manufacturing a lithium secondary battery of the first invention.
FIG. 8 is a perspective view schematically showing a method of welding a negative electrode current collector and a negative electrode plate with a laser in the lithium secondary battery manufacturing methods of the first invention and the second invention.
FIG. 9 is a perspective view schematically showing another method of welding the positive electrode current collector and the positive electrode plate with a laser in the method of manufacturing the lithium secondary battery of the first invention.
FIG. 10 is a perspective view schematically showing another method of welding the positive electrode current collector and the positive electrode plate by laser in the method of manufacturing a lithium secondary battery of the first invention.
FIG. 11 is a perspective view schematically showing another method of welding the positive electrode current collector and the positive electrode plate by laser in the method of manufacturing the lithium secondary battery of the first invention.
FIG. 12 is a perspective view schematically showing another method of welding a negative electrode current collector and a negative electrode plate by laser in the method of manufacturing a lithium secondary battery of the first invention and the second invention.
FIG. 13 is a perspective view schematically showing another method of welding the negative electrode current collector and the negative electrode plate by laser in the method of manufacturing the lithium secondary battery of the first invention and the second invention.
FIG. 14 is a schematic view showing an example of a shape of a convex connecting portion of a current collecting member used in the method of manufacturing a lithium secondary battery according to the first and second inventions.
FIG. 15 is a schematic view showing another example of the shape of the convex connection portion of the current collector used in the method of manufacturing the lithium secondary battery according to the first invention and the second invention.
FIG. 16 is a schematic diagram illustrating an example of a method of bending a metal plate (metal foil body).
FIG. 17 is a schematic diagram illustrating another example of a method of bending a metal plate (metal foil body).
FIG. 18 is a cross-sectional view showing one embodiment of a lithium secondary battery obtained by a conventional method for manufacturing a lithium secondary battery.
FIG. 19 is a perspective view showing an example of a wound internal electrode body.
[Explanation of symbols]
1A: Positive electrode plate, 1B: Negative electrode plate, 2: Narrow end surface, 3A: Normal line of the surface including the narrow end surface, 3B: Normal line of the surface including the side portion, 4A: Positive electrode current collector, 4B: Negative electrode collector 4C: Surface of the positive electrode current collector facing the positive electrode plate side, 4D: Surface of the negative electrode current collector facing the negative electrode plate side, 5 ... Connection portion, 6 ... Tip, 9 ... Connection surface, 11 ... Laser, Reference numeral 12: flat portion, 13: side portion, 15: end portion, 31A: positive electrode current collecting member, 31B: negative electrode current collecting member, 32: tip portion, 33: connection portion, 34: laser, 35: laser, 41: positive electrode Current collecting member, 42: Laser, 51A: Positive current collecting member, 51B: Negative current collecting member, 52: Connection portion, 53: Laser, 54: Current collecting member, 61: Wound internal electrode body, 62: Positive electrode plate , 63 ... negative electrode plate, 64 ... separator, 65 ... positive electrode current collecting tab, 66 ... negative electrode current collecting tab, 67 ... winding core, 6 ... lithium secondary battery, 69A ... positive electrode internal terminal, 69B ... negative electrode internal terminal, 70A ... positive electrode external terminal, 70B ... negative electrode external terminal, 71A ... positive electrode battery cover, 71B ... negative electrode battery cover, 72 ... electrode lead member, 73 ... Battery case, 74: constricted portion, 75: pressure release hole, 76: elastic body (packing), 77: insulating polymer film, 78: pressure release valve, 79: metal foil, L 1 ... Thickness of flat part, L 2 ... Thickness of the convex connection portion, θ: Angle formed by laser and normal line 3A or normal line 3B.

Claims (43)

少なくとも１枚の金属箔体からそれぞれ構成された正極板及び負極板をセパレータを介して捲回又は積層して捲回型内部電極体又は積層型内部電極体を形成し、前記正極板及び負極板の端部を、それらの端部から電流を導出するために、アルミニウム又はアルミニウム合金からなる正極集電部材、及び銅又は銅合金からなる負極集電部材のそれぞれの所定箇所（接続部）にそれぞれ接続するリチウム二次電池の製造方法であって、
前記正極集電部材の接続部の表面（接続面）の表面粗さを中心線平均表面粗さＲａで０．０５〜６．３μｍＲａとし、前記正極集電部材の接続部をパワー密度が５ｋＷ／ｍｍ２以上のレーザーで溶融して、前記正極集電部材の接続部を前記正極板の端部に溶着することにより、前記正極板の端部を前記正極集電部材の接続部に接続することを特徴とするリチウム二次電池の製造方法。A positive electrode plate and a negative electrode plate each composed of at least one metal foil body are wound or laminated via a separator to form a wound internal electrode body or a laminated internal electrode body, and the positive electrode plate and the negative electrode plate are formed. In order to derive a current from those ends, a positive current collector made of aluminum or an aluminum alloy, and a negative current collector made of copper or a copper alloy at predetermined locations (connections), respectively. A method for manufacturing a lithium secondary battery to be connected,
The surface roughness of the surface (connection surface) of the connection portion of the positive electrode current collector is set to 0.05 to 6.3 μm Ra as a center line average surface roughness Ra, and the power density of the connection portion of the positive electrode current collector is 5 kW / The end of the positive electrode plate is connected to the connection of the positive electrode current collector by melting with a laser having a diameter of 2 mm or more and welding the connection of the positive electrode current collector to the end of the positive electrode plate. A method for producing a lithium secondary battery. 前記正極集電部材及び前記負極集電部材のうちの少なくとも一方から電流を導出するための内部端子を、前記正極集電部材及び前記負極集電部材のうちの少なくとも一方に電極リード部材を用いて接続する請求項１に記載のリチウム二次電池の製造方法。An internal terminal for deriving a current from at least one of the positive current collecting member and the negative current collecting member, using an electrode lead member for at least one of the positive current collecting member and the negative current collecting member. The method for manufacturing a lithium secondary battery according to claim 1, wherein the connection is established. 前記正極集電部材及び前記負極集電部材のうちの少なくとも一方に、直接電池外部に電流を導出するように外部端子を配設する請求項１に記載のリチウム二次電池の製造方法。The method for manufacturing a lithium secondary battery according to claim 1, wherein an external terminal is provided on at least one of the positive electrode current collecting member and the negative electrode current collecting member so as to directly lead a current to the outside of the battery. 前記正極集電部材の接続部を、前記正極集電部材の前記正極板に向かって列状に連続して突出した凸状とし、凸状の前記接続部の先端部分に前記接続面を形成し、前記接続面と前記正極板の端部の狭幅端面とを対向させた状態で接続する請求項１〜３のいずれかに記載のリチウム二次電池の製造方法。The connecting portion of the positive electrode current collecting member has a convex shape that continuously protrudes in a line toward the positive electrode plate of the positive electrode current collecting member, and the connecting surface is formed at a tip portion of the convex connecting portion. 4. The method for producing a lithium secondary battery according to claim 1, wherein the connection is performed in a state where the connection surface and the narrow end surface of the end of the positive electrode plate face each other. 前記正極集電部材の前記凸状の接続部に前記レーザーを照射して、前記凸状の接続部を溶融することにより、前記凸状の接続部を前記正極板の端部に溶着する請求項４に記載のリチウム二次電池の製造方法。The laser is applied to the convex connection portion of the positive electrode current collecting member, and the convex connection portion is melted, so that the convex connection portion is welded to an end of the positive electrode plate. 5. The method for producing a lithium secondary battery according to 4. 前記正極集電部材及び前記負極集電部材のうちの少なくとも一方を、十字形、Ｙ字形、若しくはＩ字形の板状部材、又は一部に切り欠きを有する円板状部材とする請求項１〜５のいずれかに記載のリチウム二次電池の製造方法。At least one of the positive electrode current collecting member and the negative electrode current collecting member is a cross-shaped, Y-shaped, or I-shaped plate-shaped member, or a disk-shaped member having a cutout in part. 5. The method for producing a lithium secondary battery according to any one of 5. 前記正極集電部材を、前記凸状の接続部とそれ以外の平坦部とを有する形状とし、前記凸状の接続部の厚み（Ｌ２）と、前記平坦部の厚み（Ｌ１）との差を０．１ｍｍ以上とする請求項４〜６のいずれかに記載のリチウム二次電池の製造方法。The positive electrode current collecting member has a shape having the convex connection portion and the other flat portion, and the thickness (L 2 ) of the convex connection portion and the thickness (L 1 ) of the flat portion The method for producing a lithium secondary battery according to any one of claims 4 to 6, wherein the difference is 0.1 mm or more. 前記正極集電部材の前記平坦部の厚み（Ｌ１）を０．４ｍｍ以上とする請求項７に記載のリチウム二次電池の製造方法。Method for producing a lithium secondary battery according to claim 7, wherein the flat portion of the thickness of the positive electrode current collecting member (L 1) of 0.4mm or more. 前記正極集電部材における前記凸状の接続部の厚み（Ｌ２）を０．６ｍｍ以上とする請求項７又は８に記載のリチウム二次電池の製造方法。9. The method for manufacturing a lithium secondary battery according to claim 7, wherein a thickness (L 2 ) of the convex connection portion in the positive electrode current collector is 0.6 mm or more. 前記正極集電部材の前記凸状の接続部に、前記レーザーを照射して前記凸状の接続部を溶融するときに、前記正極板の端部の前記狭幅端面を含む面の法線に対して、角度θ（０＜θ≦９０°）で前記レーザーを照射する請求項５〜９のいずれかに記載のリチウム二次電池の製造方法。When irradiating the laser to the convex connection portion of the positive electrode current collecting member to melt the convex connection portion, a normal to a surface including the narrow end surface of the end portion of the positive electrode plate is formed. The method for producing a lithium secondary battery according to claim 5, wherein the laser is irradiated at an angle θ (0 <θ ≦ 90 °). 前記レーザーが照射される範囲（照射点）の径を１ｍｍ以下とする請求項５〜１０のいずれかに記載のリチウム二次電池の製造方法。The method for manufacturing a lithium secondary battery according to any one of claims 5 to 10, wherein a diameter of a range (irradiation point) irradiated with the laser is 1 mm or less. 前記正極集電部材の前記接続部と前記正極板の端部との接続を補助する接続材を、前記正極板の端部及び前記正極集電部材の前記接続部のうちの少なくとも一方に塗布し、又は前記正極板の端部と前記正極集電部材の前記接続部との間に挟時させて、前記正極集電部材の前記接続部及び前記接続材に前記レーザーを照射し、前記正極集電部材の前記接続部及び前記接続材を溶融させて、溶融した前記正極集電部材の前記接続部及び前記接続材を、前記正極板の端部に溶着させる請求項１〜１１のいずれかに記載のリチウム二次電池の製造方法。A connection material for assisting connection between the connection portion of the positive electrode current collector and the end of the positive electrode plate is applied to at least one of the end of the positive electrode plate and the connection portion of the positive electrode current collector. Alternatively, the laser is applied to the connection portion and the connection material of the positive electrode current collector while being sandwiched between an end portion of the positive electrode plate and the connection portion of the positive electrode current collector, and the positive electrode current collector is irradiated with the laser. 12. The method according to claim 1, wherein the connection part and the connection material of the electrical member are melted, and the melted connection part and the connection material of the positive electrode current collector are welded to an end of the positive electrode plate. 13. A method for producing the lithium secondary battery according to the above. 前記負極集電部材の接続部の表面（接続面）の表面粗さを中心線平均表面粗さＲａで０．０５〜６．３μｍＲａとし、前記負極集電部材の接続部をパワー密度が３ｋＷ／ｍｍ２以上のレーザーで溶融して、前記負極集電部材の接続部を前記負極板の端部に溶着することにより、前記負極板の端部を前記負極集電部材の接続部に接続する請求項１〜１２のいずれかに記載のリチウム二次電池の製造方法。The surface roughness of the surface (connection surface) of the connection portion of the negative electrode current collecting member is set to 0.05 to 6.3 μm Ra as a center line average surface roughness Ra, and the power density of the connection portion of the negative electrode current collecting member is 3 kW / The end portion of the negative electrode plate is connected to the connection portion of the negative electrode current collector by melting with a laser having a diameter of 2 mm or more and welding the connection portion of the negative electrode current collector to the end portion of the negative electrode plate. Item 13. The method for producing a lithium secondary battery according to any one of Items 1 to 12. 前記負極集電部材の接続部を、前記負極集電部材の前記負極板に向かって列状に連続して突出した凸状とし、凸状の前記接続部の先端部分に前記接続面を形成し、前記負極板の端部近傍を屈曲させて前記負極板の端部近傍の側面部が前記負極集電部材の前記接続面に対向するようにし、前記負極板の端部近傍の側面部と前記負極集電部材の前記接続面とを接続する請求項１３に記載のリチウム二次電池の製造方法。The connecting portion of the negative electrode current collecting member has a convex shape that continuously protrudes in a row toward the negative electrode plate of the negative electrode current collecting member, and the connecting surface is formed at a tip portion of the convex connecting portion. Bending the vicinity of the end of the negative electrode plate so that the side surface near the end of the negative electrode plate faces the connection surface of the negative electrode current collector, and the side surface portion near the end of the negative electrode plate and The method for manufacturing a lithium secondary battery according to claim 13, wherein the connection surface of the negative electrode current collector is connected to the connection surface. 前記負極板の端部近傍の側面部と前記負極集電部材の前記接続面とを接続するときに、前記負極板の端部近傍の側面部から前記負極集電部材の方向へ柱状晶が形成されるようにする請求項１４に記載のリチウム二次電池の製造方法。When connecting the side surface near the end of the negative electrode plate and the connection surface of the negative electrode current collecting member, columnar crystals are formed from the side surface near the end of the negative electrode current collector toward the negative electrode current collecting member. The method for manufacturing a lithium secondary battery according to claim 14, wherein: 前記負極集電部材の前記凸状の接続部に前記レーザーを照射して、前記凸状の接続部を溶融することにより、前記凸状の接続部を前記負極板の端部に溶着する請求項１４又は１５に記載のリチウム二次電池の製造方法。The laser is applied to the convex connection portion of the negative electrode current collecting member, and the convex connection portion is melted, so that the convex connection portion is welded to an end of the negative electrode plate. 16. The method for producing a lithium secondary battery according to 14 or 15. 前記正極集電部材及び前記負極集電部材のうちの少なくとも一方を、前記凸状の接続部とそれ以外の平坦部とを有する形状とし、前記凸状の接続部の厚み（Ｌ２）と、前記平坦部の厚み（Ｌ１）との差を０．１ｍｍ以上とする請求項１４〜１６のいずれかに記載のリチウム二次電池の製造方法。At least one of the positive electrode current collecting member and the negative electrode current collecting member has a shape having the convex connection portion and the other flat portion, and the thickness (L 2 ) of the convex connection portion; method for producing a lithium secondary battery according to any one of claims 14 to 16 wherein the flat portion of the thickness (L 1) the difference between 0.1mm or more. 前記負極集電部材の前記平坦部の厚み（Ｌ１）を０．２ｍｍ以上とする請求項１７に記載のリチウム二次電池の製造方法。The method of manufacturing a lithium secondary battery according to claim 17, wherein the thickness of the flat portion of the negative electrode current collector member (L 1) of 0.2mm or more. 前記負極集電部材の前記凸状の接続部の厚み（Ｌ２）が０．４ｍｍ以上である請求項１７又は１８に記載のリチウム二次電池の製造方法。Method for producing a lithium secondary battery according to the negative electrode current collector the convex connection portion of the thickness of the member (L 2) is according to claim 17 or 18 is 0.4mm or more. 前記負極集電部材の前記凸状の接続部に前記レーザーを照射して前記凸状の接続部を溶融するときに、前記負極集電部材の前記接続面に対向するように形成した前記負極板の端部近傍の側面部を含む面の法線に対して、角度θ（０≦θ≦３０°）で前記レーザーを照射する請求項１６〜１９のいずれかに記載のリチウム二次電池の製造方法。The negative electrode plate formed so as to face the connection surface of the negative electrode current collecting member when the convex connection portion of the negative electrode current collecting member is irradiated with the laser to melt the convex connection portion. 20. The lithium secondary battery according to claim 16, wherein the laser is irradiated at an angle θ (0 ≦ θ ≦ 30 °) with respect to a normal to a surface including a side surface near an end of the lithium secondary battery. Method. 前記負極集電部材の前記凸状の接続部に前記レーザーを照射して前記凸状の接続部を溶融するときに、前記凸状の接続部の厚みをＬ２（ｍｍ）、前記レーザーの前記パワー密度をＥ（ｋＷ／ｍｍ２）としたときに、下記式（１）を満足する請求項１６〜２０のいずれかに記載のリチウム二次電池の製造方法。
Figure 2004220953
 When the convex connecting portion of the negative electrode current collector is irradiated with the laser to melt the convex connecting portion, the thickness of the convex connecting portion is set to L 2 (mm), 21. The method for producing a lithium secondary battery according to claim 16, wherein the following expression (1) is satisfied when the power density is E (kW / mm 2 ).
Figure 2004220953
 前記レーザーが照射される範囲（照射点）の径を１ｍｍ以下とする請求項１６〜２１のいずれかに記載のリチウム二次電池の製造方法。22. The method for manufacturing a lithium secondary battery according to claim 16, wherein a diameter of a range (irradiation point) irradiated with the laser is 1 mm or less. 前記負極集電部材の前記接続部と前記負極板の端部との接続を補助する接続材を、前記負極板の端部及び前記負極集電部材の前記接続部のうちの少なくとも一方に塗布し、又は前記負極板の端部と前記負極集電部材の前記接続部との間に挟時させて、前記負極集電部材の前記接続部及び前記接続材に前記レーザーを照射し、前記負極集電部材の前記接続部及び前記接続材を溶融させて、溶融した前記負極集電部材の前記接続部及び前記接続材を、前記負極板の端部に溶着させる請求項１３〜２２のいずれかに記載のリチウム二次電池の製造方法。A connection material for assisting connection between the connection part of the negative electrode current collector and the end of the negative electrode plate is applied to at least one of the end part of the negative electrode plate and the connection part of the negative electrode current collector. Or by irradiating the laser to the connection portion and the connection material of the negative electrode current collection member while being sandwiched between an end portion of the negative electrode plate and the connection portion of the negative electrode current collection member, 23. The method according to claim 13, wherein the connecting portion and the connecting material of the electrical member are melted, and the melted connecting portion and the connecting material of the negative electrode current collecting member are welded to an end of the negative electrode plate. A method for producing the lithium secondary battery according to the above. 少なくとも１枚の金属箔体からそれぞれ構成された正極板及び負極板をセパレータを介して捲回又は積層して捲回型内部電極体又は積層型内部電極体を形成し、前記正極板及び負極板の端部を、それらの端部から電流を導出するために、アルミニウム又はアルミニウム合金からなる正極集電部材、及び銅又は銅合金からなる負極集電部材のそれぞれの所定箇所（接続部）にそれぞれ接続するリチウム二次電池の製造方法であって、
前記負極集電部材の接続部の表面（接続面）の表面粗さを中心線平均表面粗さＲａで０．０５〜６．３μｍＲａとし、前記負極集電部材の接続部をパワー密度が３ｋＷ／ｍｍ２以上のレーザーで溶融して、前記負極集電部材の接続部を前記負極板の端部に溶着することにより、前記負極板の端部を前記負極集電部材の接続部に接続することを特徴とするリチウム二次電池の製造方法。A positive electrode plate and a negative electrode plate each composed of at least one metal foil body are wound or laminated via a separator to form a wound internal electrode body or a laminated internal electrode body, and the positive electrode plate and the negative electrode plate are formed. In order to derive a current from those ends, a positive current collector made of aluminum or an aluminum alloy, and a negative current collector made of copper or a copper alloy at predetermined locations (connections), respectively. A method for manufacturing a lithium secondary battery to be connected,
The surface roughness of the surface (connection surface) of the connection portion of the negative electrode current collecting member is set to 0.05 to 6.3 μm Ra as a center line average surface roughness Ra, and the power density of the connection portion of the negative electrode current collecting member is 3 kW / The end of the negative electrode plate is connected to the connection portion of the negative electrode current collector by melting with a laser having a diameter of 2 mm or more and welding the connection portion of the negative electrode current collector to the end of the negative electrode plate. A method for producing a lithium secondary battery. 前記正極集電部材及び前記負極集電部材のうちの少なくとも一方から電流を導出するための内部端子を、前記正極集電部材及び前記負極集電部材のうちの少なくとも一方に電極リード部材を用いて接続する請求項２４に記載のリチウム二次電池の製造方法。An internal terminal for deriving a current from at least one of the positive current collecting member and the negative current collecting member, using an electrode lead member for at least one of the positive current collecting member and the negative current collecting member. The method for manufacturing a lithium secondary battery according to claim 24, wherein the connection is established. 前記正極集電部材及び前記負極集電部材のうちの少なくとも一方に、直接電池外部に電流を導出するように外部端子を配設する請求項２４に記載のリチウム二次電池の製造方法。25. The method for manufacturing a lithium secondary battery according to claim 24, wherein an external terminal is provided on at least one of the positive electrode current collecting member and the negative electrode current collecting member so as to directly draw a current to the outside of the battery. 前記負極集電部材の接続部を、前記負極集電部材の前記負極板に向かって列状に連続して突出した凸状とし、凸状の前記接続部の先端部分に前記接続面を形成し、前記負極板の端部近傍を屈曲させて前記負極板の端部近傍の側面部が前記負極集電部材の前記接続面に対向するようにし、前記負極板の端部近傍の側面部と前記負極集電部材の前記接続面とを接続する請求項２４〜２６のいずれかに記載のリチウム二次電池の製造方法。The connecting portion of the negative electrode current collecting member has a convex shape that continuously protrudes in a row toward the negative electrode plate of the negative electrode current collecting member, and the connecting surface is formed at a tip portion of the convex connecting portion. Bending the vicinity of the end of the negative electrode plate so that the side surface near the end of the negative electrode plate faces the connection surface of the negative electrode current collector, and the side surface portion near the end of the negative electrode plate and The method for manufacturing a lithium secondary battery according to any one of claims 24 to 26, wherein the lithium secondary battery is connected to the connection surface of a negative electrode current collector. 前記負極板の端部近傍の側面部と前記負極集電部材の前記接続面とを接続するときに、前記負極板の端部近傍の側面部から前記負極集電部材の方向へ柱状晶が形成されるようにする請求項２７に記載のリチウム二次電池の製造方法。When connecting the side surface near the end of the negative electrode plate and the connection surface of the negative electrode current collecting member, columnar crystals are formed from the side surface near the end of the negative electrode current collector toward the negative electrode current collecting member. 28. The method for manufacturing a lithium secondary battery according to claim 27, wherein: 前記負極集電部材の前記凸状の接続部に前記レーザーを照射して、前記凸状の接続部を溶融することにより、前記凸状の接続部を前記負極板の端部に溶着する請求項２７又は２８に記載のリチウム二次電池の製造方法。The laser is applied to the convex connection portion of the negative electrode current collecting member, and the convex connection portion is melted, so that the convex connection portion is welded to an end of the negative electrode plate. 29. The method for producing a lithium secondary battery according to 27 or 28. 前記正極集電部材及び前記負極集電部材のうちの少なくとも一方を、十字形、Ｙ字形、若しくはＩ字形の板状部材、又は一部に切り欠きを有する円板状部材とする請求項２４〜２９のいずれかに記載のリチウム二次電池の製造方法。25. At least one of the positive electrode current collecting member and the negative electrode current collecting member is a cross-shaped, Y-shaped, or I-shaped plate-shaped member, or a disk-shaped member having a cutout in part. 30. The method for producing a lithium secondary battery according to any one of the items 29. 前記負極集電部材を、前記凸状の接続部とそれ以外の平坦部とを有する形状とし、前記凸状の接続部の厚み（Ｌ２）と、前記平坦部の厚み（Ｌ１）との差を０．１ｍｍ以上とする請求項２７〜３０のいずれかに記載のリチウム二次電池の製造方法。The negative electrode current collector has a shape having the convex connection portion and the other flat portion, and a thickness (L 2 ) of the convex connection portion and a thickness (L 1 ) of the flat portion 31. The method for manufacturing a lithium secondary battery according to claim 27, wherein the difference is 0.1 mm or more. 前記負極集電部材の前記平坦部の厚み（Ｌ１）を０．２ｍｍ以上とする請求項３１に記載のリチウム二次電池の製造方法。The method of manufacturing a lithium secondary battery according to claim 31, wherein the thickness of the flat portion of the negative electrode current collector member (L 1) of 0.2mm or more. 前記負極集電部材の前記凸状の接続部の厚み（Ｌ２）が０．４ｍｍ以上である請求項３１又は３２に記載のリチウム二次電池の製造方法。Method for producing a lithium secondary battery according to the negative electrode current collector the convex connection portion of the thickness of the member (L 2) according to claim 31 or 32 is 0.4mm or more. 前記負極集電部材の前記凸状の接続部に前記レーザーを照射して前記凸状の接続部を溶融するときに、前記負極集電部材の前記接続面に対向するように形成した前記負極板の端部近傍の側面部を含む面の法線に対して、角度θ（０≦θ≦３０°）で前記レーザーを照射する請求項２９〜３３のいずれかに記載のリチウム二次電池の製造方法。The negative electrode plate formed so as to face the connection surface of the negative electrode current collecting member when the convex connection portion of the negative electrode current collecting member is irradiated with the laser to melt the convex connection portion. 34. The lithium secondary battery according to claim 29, wherein the laser is irradiated at an angle [theta] (0≤ [theta] ≤30 [deg.]) With respect to a normal to a surface including a side surface near the end of the lithium secondary battery. Method. 前記負極集電部材の前記凸状の接続部に前記レーザーを照射して前記凸状の接続部を溶融するときに、前記凸状の接続部の厚みをＬ２（ｍｍ）、前記レーザーの前記パワー密度をＥ（ｋＷ／ｍｍ２）としたときに、下記式（２）を満足する請求項２９〜３４のいずれかに記載のリチウム二次電池の製造方法。
Figure 2004220953
 When the convex connecting portion of the negative electrode current collector is irradiated with the laser to melt the convex connecting portion, the thickness of the convex connecting portion is set to L 2 (mm), 35. The method for producing a lithium secondary battery according to claim 29, wherein the following formula (2) is satisfied when the power density is E (kW / mm 2 ).
Figure 2004220953
 前記レーザーが照射される範囲（照射点）の径を１ｍｍ以下とする請求項２９〜３５のいずれかに記載のリチウム二次電池の製造方法。The method for manufacturing a lithium secondary battery according to any one of claims 29 to 35, wherein a diameter of a range (irradiation point) irradiated with the laser is 1 mm or less. 前記負極集電部材の前記接続部と前記負極板の端部との接続を補助する接続材を、前記負極板の端部及び前記負極集電部材の前記接続部のうちの少なくとも一方に塗布し、又は前記負極板の端部と前記負極集電部材の前記接続部との間に挟時させて、前記負極集電部材の前記接続部及び前記接続材に前記レーザーを照射し、前記負極集電部材の前記接続部及び前記接続材を溶融させて、溶融した前記負極集電部材の前記接続部及び前記接続材を、前記負極板の端部に溶着させる請求項２４〜３６のいずれかに記載のリチウム二次電池の製造方法。A connection material for assisting connection between the connection part of the negative electrode current collector and the end of the negative electrode plate is applied to at least one of the end part of the negative electrode plate and the connection part of the negative electrode current collector. Or by irradiating the laser to the connection portion and the connection material of the negative electrode current collection member while being sandwiched between an end portion of the negative electrode plate and the connection portion of the negative electrode current collection member, 37. The method according to claim 24, wherein the connection portion and the connection material of the electrical member are melted, and the melted connection portion and the connection material of the negative electrode current collection member are welded to an end of the negative electrode plate. A method for producing the lithium secondary battery according to the above. 前記レーザーが連続波である請求項１〜３７のいずれかに記載のリチウム二次電池の製造方法。The method for manufacturing a lithium secondary battery according to claim 1, wherein the laser is a continuous wave. 前記レーザーがＹＡＧレーザーである請求項１〜３８のいずれかに記載のリチウム二次電池の製造方法。The method for producing a lithium secondary battery according to any one of claims 1 to 38, wherein the laser is a YAG laser. 前記リチウム二次電池の電池容量が２Ａｈ以上である請求項１〜３９のいずれかに記載のリチウム二次電池の製造方法。The method for manufacturing a lithium secondary battery according to any one of claims 1 to 39, wherein a battery capacity of the lithium secondary battery is 2 Ah or more. 前記リチウム二次電池が車載用電池である請求項１〜４０のいずれかに記載のリチウム二次電池の製造方法。The method for manufacturing a lithium secondary battery according to any one of claims 1 to 40, wherein the lithium secondary battery is a vehicle-mounted battery. 前記リチウム二次電池が電気自動車用又はハイブリッド電気自動車用電池である請求項４１に記載のリチウム二次電池の製造方法。42. The method for manufacturing a lithium secondary battery according to claim 41, wherein the lithium secondary battery is a battery for an electric vehicle or a hybrid electric vehicle. 前記リチウム二次電池がエンジン起動用電池である請求項４１又は４２に記載のリチウム二次電池の製造方法。43. The method for manufacturing a lithium secondary battery according to claim 41, wherein the lithium secondary battery is an engine starting battery.
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WO2008035495A1 (en) * 2006-09-20 2008-03-27 Panasonic Corporation Secondary battery and method for manufacturing secondary battery
US7976979B2 (en) 2006-09-20 2011-07-12 Panasonic Corporation Secondary battery and method for manufacturing secondary battery
KR101057954B1 (en) 2006-09-20 2011-08-18 파나소닉 주식회사 Secondary Battery and Manufacturing Method of Secondary Battery
US8142922B2 (en) 2006-09-20 2012-03-27 Panasonic Corporation Secondary battery and method for manufacturing secondary battery

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