JP2004071266A

JP2004071266A - Nonaqueous electrolyte secondary battery and its manufacturing process

Info

Publication number: JP2004071266A
Application number: JP2002226839A
Authority: JP
Inventors: Naoya Nakanishi; 中西　直哉; Koichi Sato; 佐藤　広一; Atsuhiro Funabashi; 船橋　淳浩; Toshiyuki Noma; 能間　俊之; Yasuhiro Yamauchi; 山内　康弘; Tokuyuki Miyazaki; 宮崎　徳之
Original assignee: Sanyo Electric Co Ltd
Current assignee: Sanyo Electric Co Ltd
Priority date: 2002-08-05
Filing date: 2002-08-05
Publication date: 2004-03-04

Abstract

<P>PROBLEM TO BE SOLVED: To reduce an internal resistance, increase a volume efficiency, and improve a productivity in a nonaqueous electrolyte secondary battery storing a wind electrode body inside a battery can and taking out an electric power generated by the electrode body from a pair of positive/negative electrode terminal parts to the outside. <P>SOLUTION: In this nonaqueous electrolyte secondary battery, one electrode terminal part is formed of one lid body 53 of a battery can 5 and a power collecting plate 61 is joined with one electrode edge of the wind electrode body 4. The surface of the power collecting plate 61 is fixed with a terminal connecting member 9, the terminal connecting member 9 is firmly fitted in a hole opened in the bottom wall of the battery can 5 to face to the outside of the battery can 5, the battery can 5 and the terminal connecting member 9 are formed of a same material in their mutual joining part, and welding 90 is performed to the joining part from the outside of the battery can 5. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、リチウムイオン二次電池の如く、筒状の電池缶の内部に発電要素となる電極体を収容して、該電極体が発生する電力を外部に取り出すことが出来る非水電解液二次電池、並びにその製造方法に関するものである。
【０００２】
【従来の技術】
近年、携帯型電子機器、電気自動車等の電源として、エネルギー密度の高いリチウムイオン二次電池が注目されている。円筒型のリチウムイオン二次電池は、例えば図１３に示す様に、正極缶（１）の内部に巻き取り電極体（２）を収容して、正極缶（１）の開口部に封口板（１１）を固定したものであって、正極缶（１）と封口板（１１）の間には絶縁部材（１２）が介在している。又、封口板（１１）には、ガス排出弁（１４）を内蔵した負極端子（１３）が取り付けられている。
【０００３】
巻き取り電極体（２）は、それぞれ帯状の負極（２１）、セパレータ（２２）、及び正極（２３）からなり、負極（２１）及び正極（２３）はそれぞれセパレータ（２２）上に幅方向へずらして重ね合わされ、渦巻き状に巻き取られている。これによって、巻き取り電極体（２）の軸方向の両端部の内、一方の端部では、セパレータ（２２）の端縁よりも外方へ負極（２１）の端縁が突出すると共に、他方の端部では、セパレータ（２２）の端縁よりも正極（２３）の端縁が突出している。
巻き取り電極体（２）の両端部にはそれぞれ集電板（３）が設置されている。そして、負極側の集電板（３）はタブ（３１）を介して封口板（１１）の裏面に溶接され、正極側の集電板（３）はタブ（３１）を介して正極缶（１）の底面に溶接されている。
これによって、巻き取り電極体（２）が発生する電力を負極端子（１３）と正極缶（１）から外部へ取り出すことが出来る。
負極端子（１３）は、負極電位で安定なニッケル、銅或いはステンレス鋼から形成され、正極缶（１）は、正極電位で安定なアルミニウム或いはアルミニウム合金から形成されている。
【０００４】
尚、上記リチウムイオン二次電池においては、図１４に示す如く複数本の電池Ａ、Ｂを直列に接続して、所要の出力電圧を得ることが行なわれる。
【０００５】
【発明が解決しようとする課題】
しかしながら、図１３に示す従来のリチウムイオン二次電池においては、特に巻き取り電極体（２）の正極と正極缶（１）の底壁との連結に、タブ（３１）を用いた連結構造が採用されていたので、巻き取り電極体（２）と正極缶（１）の間の電流経路長が大きく、これによって内部抵抗が大きくなる問題や、タブ（３１）の配置のためにデッドスペースが大きくなって、電池の体積効率が低下する問題があった。更には、タブ（３１）の先端部を正極缶（１）の底面に溶接する作業が煩雑であり、生産性が悪い問題があった。
そこで本発明の目的は、内部抵抗の低減、体積効率の増大、並びに生産性の向上を同時に図ることが可能な非水電解液二次電池、及びその製造方法を提供することである。
【０００６】
【課題を解決する為の手段】
本発明に係る非水電解液二次電池は、筒状の電池缶の内部に電極体が収容されて、該電極体が発生する電力を正負一対の電極端子部から外部に取り出すことが出来るものであって、電池缶の一方の端部を形成する底壁によって一方の電極端子部が形成され、前記電極体の一方の電極端縁には集電板が接合されている。
集電板の電極体とは反対側の表面には、端子連結部が突設され、該端子連結部は、電池缶の底壁に開設された孔へ緊密に嵌入して、電池缶の外部へ臨出し、電池缶と端子連結部とは互いの接合部にて同一材質であって、電池缶の外側から該接合部に対して溶接が施されている。
【０００７】
上記本発明の非水電解液二次電池においては、集電板の表面に突設した端子連結部が電池缶の底壁に開設した孔に嵌合して、電極体と電池缶の間の電気的接続が行なわれるので、電極体から電池缶へ至る電流経路長は従来のタブ接続に比べて短縮され、該電流経路の電気抵抗は極めて低いものとなる。
又、集電板の表面に突設した端子連結部が電池缶の底壁に開設した孔に嵌合して、端子連結部の大部分が電池缶底壁に埋設されることになるので、電池缶の内部にデッドスペースは殆ど発生しない。
更に又、端子連結部と電池缶底壁の間の溶接部は、電池缶の外側に露出しているので、溶接作業を電池缶の外側から行なうことが出来、これによって溶接作業が容易なものとなって、溶接の信頼性も向上する。
尚、電池缶と端子連結部とは互いの接合部にて同一材質であるので、該接合部に対する溶接に欠陥発生の虞はなく、溶接部に高い信頼性が得られる。
【０００８】
具体的構成において、前記端子連結部は外周面が円筒面若しくはテーパ面であると共に、電池缶の底壁に開設された孔は内周面が円筒面若しくはテーパ面であって、端子連結部の外周面と電池缶の底壁に開設された孔の内周面とが互いに密着している。
これによって、端子連結部と電池缶底壁との間の接触面積が十分に大きくなって、電流経路の電気抵抗が低減される。
【０００９】
更に具体的には、電池缶の底壁から露出する端子連結部の表面は、電池缶の底壁の表面と同一若しくは略同一の平面上に揃っており、電池缶底壁及び端子連結部の表面には、前記溶接部の内側と外側を溶接部に沿って伸びる周壁を有する２つの凹部が形成されている。
該具体的構成によれば、溶接部が２つの周壁により挟まれて、溶接部の熱が周囲に向かって放散する際の熱流路が絞られることになるため、レーザ溶接時の溶接部からの熱放散が抑制され、この結果、溶接部の温度が急激に低下する事態が回避される。従って、溶接部にクラック等の欠陥が発生することはない。
【００１０】
更に又、電池缶底壁及び端子連結部の表面を覆って、平板状の接続補助板（５５）が固定されている。
該具体的構成によれば、接続補助板（５５）の平坦な表面が電極端子部を形成することとなる。従って、例えば複数本の電池を直列に接続する場合において、該電極端子部に対して他の電池の電極端子部が確実且つ安定して接触することなる。
【００１１】
本発明に係る非水電解液二次電池の製造方法は、
電極体を作製する工程と、
作製された電極体の一方の電極端縁に対し、一方の電極端子部を構成すべき端子機構の基端部を連結する工程と、
作製された電極体の他方の電極端縁に対し、他方の電極端部を構成すべき電池缶の底壁に向けて端子連結部が突設された集電板を接合する工程と、
前記端子連結部を電池缶の底壁に開設した孔へ嵌入せしめて電池缶の外部へ臨出させ、該端子連結部と電池缶底壁との接合部に対して、電池缶の外側から溶接を施す工程と、
電池缶に非水電解液を注入した後、電池缶を密閉する工程
とを有している。
【００１２】
上記本発明の非水電解液二次電池の製造方法によれば、上記本発明の非水電解液二次電池を容易に製造することが可能であって、これによって生産性の向上を図ることが出来る。又、端子連結部と電池缶底壁との接合部に対して電池缶の外側から溶接を施すので、溶接作業が容易であり、これによって確実で信頼性の高い溶接が実現されることとなり、ひいては内部抵抗の低減が図られる。
【００１３】
【発明の効果】
本発明に係る非水電解液二次電池及びその製造方法によれば、内部抵抗の低減、体積効率の増大、並びに生産性の向上を同時に図ることが出来る。
【００１４】
【発明の実施の形態】
以下、本発明をリチウムイオン二次電池に実施した形態につき、図面に沿って具体的に説明する。
全体構成
本発明に係るリチウムイオン二次電池は、図１に示す如く、円筒状の電池缶（５）の内部に巻き取り電極体（４）を収容して構成されている。
電池缶（５）は、円筒状の筒体（５１）の両開口部に蓋体（５２）（５３）を溶接固定して構成され、下方の蓋体（５３）によって正極端子部を形成している。又、電池缶（５）の上方の蓋体（５２）には、負極端子機構（７）が取り付けられており、該負極端子機構（７）を構成する負極端子（８）によって負極端子部を形成している。
この結果、前記正極端子部と負極端子部から巻き取り電極体（４）の発生電力を外部に取り出すことが出来る。
尚、電池缶（５）の上方の蓋体（５２）には、缶内の圧力が上昇したときに圧力を開放するガス排出弁（５０）が取り付けられている。
【００１５】
巻き取り電極体（４）は、図２に示す如く、それぞれ帯状の負極（４１）と正極（４３）の間に帯状のセパレータ（４２）を介在させて、これらを渦巻き状に巻回して構成されている。負極（４１）は、銅箔からなる帯状芯体（４５）の両面に炭素材料を含む負極活物質（４４）を塗布して構成され、正極（４３）は、アルミニウム箔からなる帯状芯体（４７）の両面にリチウム複合酸化物からなる正極活物質（４６）を塗布して構成されている。セパレータ（４２）には、非水電解液が含浸されている。
負極（４１）には、負極活物質（４４）の塗布されている塗工部と、負極活物質の塗布されていない非塗工部とが形成されている。又、正極（４３）にも、正極活物質（４６）の塗布されている塗工部と、正極活物質の塗布されていない非塗工部とが形成されている。
【００１６】
負極（４１）及び正極（４３）はそれぞれセパレータ（４２）上に幅方向へずらして重ね合わせ、負極（４１）及び正極（４３）の前記非塗工部をセパレータ（４２）の両端縁からそれぞれ外側へ突出させる。そして、これらを渦巻き状に巻き取ることによって巻き取り電極体（４）が構成される。該巻き取り電極体（４）においては、巻き軸方向の両端部の内、一方の端部では、負極（４１）の非塗工部の芯体端縁（４８）が、セパレータ（４２）の一方の端縁よりも外方へ突出し、他方の端部では、正極（４３）の非塗工部の芯体端縁（４８）が、セパレータ（４２）の他方の端縁よりも外方へ突出している。
【００１７】
集電構造
図１に示す如く、巻き取り電極体（４）の両端部にはそれぞれ円板状の集電板（６）（６１）がレーザ溶接されている。
負極側の集電板（６）は、ニッケル、銅、表面がニッケルメッキされた銅、若しくは表面がニッケルメッキされた鉄を材料として形成され、図４に示す如く中央孔（６０）を有する円板状の本体に、中央孔（６０）を中心として放射状に伸びる複数条（実施例では４条）の円弧状凸部（６２）が一体成型され、裏面側即ち巻き取り電極体（４）側に突出している。
該集電板（６）の表面には、２本の円弧状凸部（６２）（６２）に挟まれた４つの４分の１円領域に、それぞれ扇形を呈する扁平な４つの連結片（６３）〜（６３）が円陣に配置され、溶接固定されている。これら４つの連結片（６３）〜（６３）の外周面は、一定の半径を有する１つの円筒面を形成する。
【００１８】
正極側の集電板（６１）は、アルミニウム若しくはアルミニウム合金製であって、図９（ａ）に示す如く中央孔（６０）を有する円板状の本体に、中央孔（６０）を中心として放射状に伸びる複数条（実施例では４条）の円弧状凸部（６２）が一体成型され、裏面側即ち巻き取り電極体（４）側に突出している。
該集電板（６１）の表面には、前記中央孔（６０）を塞ぐ位置に、図９（ｂ）に示す如く円板状を呈するアルミニウム製の端子連結部材（９）が固定されている。該端子連結部材（９）の表面には、円形の凹部（９１）が形成されている。
尚、端子連結部材（９）は、集電板（６１）に一体成型によって形成することも可能である。
【００１９】
巻き取り電極体（４）の両端部に集電板（６）（６１）を溶接する工程では、先ず、集電板（６）（６１）を巻き取り電極体（４）の芯体端縁（４８）に押し付ける。これによって、集電板（６）（６１）の円弧状凸部（６２）は、巻き取り電極体（４）の芯体端縁（４８）に食い込み、円弧状凸部（６２）と芯体端縁（４８）の間には、円筒面からなる接合面が形成される。この状態で、集電板（６）（６１）の円弧状凸部（６２）の内周面に向けてレーザビームを照射して、レーザ溶接を施す。この結果、集電板（６）の円弧状凸部（６２）と巻き取り電極体（４）の芯体端縁（４８）とが、大きな接触面積で互いに接合されることになる。
【００２０】
負極側の端子連結構造
負極端子機構（７）は、図１及び図３に示す様に、集電板（６）上の複数の連結片（６３）と溶接されるべき円筒状のスカート部（７０）を有する端子接続部材（７１）と、上方の蓋体（５２）の中央孔に取り付けられるべき第１及び第２絶縁部材（７２）（７３）と、端子接続部材（７１）及び両絶縁部材（７２）（７３）を蓋体（５２）に締結するための円筒状のリベット部材（７６）と、リベット部材（７６）の開口を塞ぐゴム栓（７９）と、該ゴム栓（７９）を覆ってリベット部材（７６）の表面に溶接された負極端子（８）とを具えている。
尚、電解液注入前の段階では、ゴム栓（７９）と負極端子（８）を外した状態で負極端子機構（７）を組み立て、電解液注入後、リベット部材（７６）にゴム栓（７９）を取り付け、負極端子（８）をリベット部材（７６）の表面に溶接固定する。
【００２１】
端子接続部材（７１）は、ニッケル、表面がニッケルメッキされた鉄、表面がニッケルメッキされた銅、或いはステンレス鋼を材料として形成されている。
第１絶縁部材（７２）は、概ね円板状を呈して蓋体（５２）の裏面に圧着し、第２絶縁部材（７３）は、概ね円筒状を呈して蓋体（５２）の中央孔内周面に圧着し、両絶縁部材（７２）（７３）によって、蓋体（５２）と負極端子機構（７）の間の気密性を維持するものであり、何れも、ＰＥ、ＰＰ、ナイロン、フッ素系樹脂（ＰＦＡ、ＰＴＦＥ）、ＰＰＳ、或いはＰＥＥＫから形成されている。
【００２２】
リベット部材（７６）は、表面がニッケルメッキされた鉄、ニッケル、銅、表面がニッケルメッキされた銅、或いは軟鉄を材料として、図３の如く円板部（７７）の裏面に円筒部（７８）を突設して形成され、図６に示す様に、蓋体（５２）に組み付けられた端子接続部材（７１）及び両絶縁部材（７２）（７３）の中央開口へリベット部材（７６）の円筒部（７８）を挿入した状態で、該円筒部（７８）の下端部（７８ａ）をかしめることによって、端子接続部材（７１）及び両絶縁部材（７２）（７３）が蓋体（５２）に締結される。
【００２３】
負極端子（８）は、厚さ約０．２ｍｍのニッケル層（８１）と厚さ約３０μｍのアルミニウム層（８２）の２層のクラッド接合構造を有している。尚、クラッド接合には、一般的な減圧下での圧延によって２層を接合する方法の他、加熱下での圧延、或いは圧延後の加熱によって、２層の接合界面に拡散層を生成する方法を採用することが出来る。
これによって、ニッケル層（８１）とアルミニウム層（８２）は互いに密着して一体化される。従って、ニッケル層（８１）とアルミニウム層（８２）の界面に水分などが浸入する虞はなく、これによって異種金属どうしの接触による電気腐食が防止される。
尚、ニッケル層（８１）とアルミニウム層（８２）の接合には、クラッド接合に限らず、ニッケル層（８１）の表面にアルミニウムメッキを施してアルミニウム層（８２）を形成する方法を採用することも可能である。
【００２４】
巻き取り電極体（４）の負極側の集電板（６）に設けられた複数の連結片（６３）の外周面は、負極端子機構（７）を構成する端子接続部材（７１）のスカート部（７０）の内周面と密着可能であって、図６に示す様に、蓋体（５２）に対して負極端子機構（７）を組み付ける一方、巻き取り電極体（４）に対して連結片（６３）を具えた集電板（６）を固定した後、図７に示す如く、端子接続部材（７１）のスカート部（７０）の内周面と集電板（６）の連結片（６３）の外周面とを密着させ、この状態で、矢印の如く端子接続部材（７１）のスカート部（７０）の外側からレーザビームを照射して、端子接続部材（７１）のスカート部（７０）と集電板（６）の連結片（６３）とを互いにレーザ溶接する。
【００２５】
尚、４つの連結片（６３）〜（６３）は集電板（６）に一体成型することも可能である。又、扇形の連結片（６３）に代えて、図５に示す如き円弧状の連結片（６４）を集電板（６）に突設して、複数の連結片（６４）の外周面によって、端子接続部材（７１）のスカート部（７０）の内周面と密着すべき円筒面を形成することも可能である。又、該連結片（６４）は、集電板（６）の一部を切り起こすことによって形成することも可能である。
【００２６】
正極側の端子連結構造
一方、図１の如く巻き取り電極体（４）の正極側の集電板（６１）に固定されている端子連結部材（９）は、電池缶（５）の下方の蓋体（５３）に連結される。
電池缶（５）の下方の蓋体（５３）には、図１０に示す如く端子連結部材（９）の外径と一致する内径の中央孔（５８）が開設されており、端子連結部材（９）を蓋体（５３）の中央孔（５８）に嵌入せしめ、図１の如く蓋体（５３）の表面と端子連結部材（９）の表面を揃えた状態で、蓋体（５３）と端子連結部材（９）の接合部に対し、図８に示す様に円周線に沿う経路で蓋体（５３）の外側からレーザビームを照射し、レーザ溶接（９０）を施す。これによって、端子連結部材（９）は蓋体（５３）に固定される。
【００２７】
上記端子連結構造において、端子連結部材（９）の表面には、前述の凹部（９１）によって、溶接部（９０）の内側に位置する周壁が形成されると共に、蓋体（５３）の表面には、円周線に沿って伸びる溝（５４）が凹設されて、溶接部（９０）の外側に位置する周壁が形成されている。
この結果、溶接部（９０）が２つの周壁により挟まれて、レーザ溶接時の熱放散が抑制されるため、溶接部（９０）の温度が急激に低下する事態が回避される。従って、溶接部（９０）にクラック等の欠陥が発生することはない。
【００２８】
尚、電池缶（５）の下方の蓋体（５３）の表面には、必要に応じて、図１１に示す如くアルミニウム製の接続補助板（５５ａ）がレーザ溶接され、該接続補助板（５５ａ）によって平坦な表面の正極端子部が形成される。
これによって、図１１の如く２本の電池Ａ、Ｂを互いに直列に接続する場合、一方の電池Ｂの負極端子部である負極端子（８ｂ）を、他方の電池Ａの正極端子部である接続補助板（５５ａ）に対し、確実且つ安定して接触させることが可能となる。
【００２９】
電池の組立方法
図２に示す巻き取り電極体（４）を作製した後、巻き取り電極体（４）の負極端縁に、図４に示す集電板（６）をレーザ溶接によって接合すると共に、巻き取り電極体（４）の正極端縁に、図９（ｂ）に示す集電板（６１）をレーザ溶接によって接合する。
次に、図６及び図７に示す様に、蓋体（５２）に対してゴム栓（７９）及び負極端子（８）以外の負極端子機構（７）を組み付けた後、集電板（６）上の連結片（６３）を端子接続部材（７１）のスカート部（７０）に溶接する。該溶接は、端子接続部材（７１）のスカート部（７０）の外側からレーザビームを照射することによって行なわれる。
その後、図１０に示す如く、集電板（６１）上の端子連結部材（９）を電池缶（５）の蓋体（５３）の中央孔（５８）へ嵌入せしめ、端子連結部材（９）の表面を蓋体（５３）の表面に臨出させる。そして、電池缶（５）の外側から端子連結部材（９）と蓋体（５３）の接合部に溶接を施す。
最後に、負極端子機構（７）のリベット部材（７６）の中央孔から電池缶（５）の内部へ電解液を注入した後、リベット部材（７６）の開口部にゴム栓（７９）を取り付け、更に負極端子（８）をリベット部材（７６）の表面に溶接して、図１の如く電池缶（５）を密閉する。
【００３０】
上記本発明のリチウムイオン二次電池においては、負極端子（８）がニッケル層（８１）とアルミニウム層（８２）のクラッド接合構造を有しているので、図１１に示す如く２本の電池Ａ、Ｂを直列に接続した場合、一方の電池Ｂの負極端子（８ｂ）のアルミニウム層（８２）と他方の電池Ａのアルミニウム製接続補助板（５５ａ）とが互いに接触することとなり、異種金属どうしの接触に起因する電気腐食は発生しない。又、接続補助板（５５）を省略した構成においても、一方の電池Ｂの負極端子（８ｂ）のアルミニウム層（８２）と他方の電池Ａのアルミニウム製蓋体（５３ａ）若しくはアルミニウム製端子連結部材（９ａ）とが接触するので、異種金属どうしの接触に起因する電気腐食は発生しない。
【００３１】
尚、負極端子（８）をニッケル層（８１）とアルミニウム層（８２）のクラッド接合構造とする構成に代えて、図１２に示す如く接続補助板（５５）をアルミニウム層（５６）とニッケル層（５７）のクラッド接合構造とする構成を採用した場合にも、同一金属どうしの接触となって、異種金属どうしの接触に起因する電気腐食は発生しない。
【００３２】
又、上記本発明のリチウムイオン二次電池においては、巻き取り電極体（４）を負極端子機構（７）に連結する構造として、負極側の集電板（６）に固定した連結片（６３）と、負極端子機構（７）を構成する端子接続部材（７１）のスカート部（７０）とを、従来の如きタブを介することなく互いに直接に接合した構造を採用することによって、生産性の改善、巻き取り電極体（４）と負極端子（８）の間の電流経路長の短縮、電池缶（５）内のデッドスペースの削減、並びに内部抵抗の低減が図られる。
【００３３】
更に又、上記本発明のリチウムイオン二次電池においては、巻き取り電極体（４）を正極端子部となる電池缶（５）の蓋体（５３）に連結する構造として、巻き取り電極体（４）に負極端子機構（７）を連結した後、正極側の集電板（６１）に固定した端子連結部材（９）を、蓋体（５３）に開設した中央孔（５８）に嵌合せしめて、端子連結部材（９）と蓋体（５３）とを、従来の如きタブを介することなく直接に接合した構造を採用することによって、缶外からのレーザ溶接を可能としたことによる生産性の改善が図られると共に、巻き取り電極体（４）と蓋体（５３）の間の電流経路長の短縮、内部抵抗の低減、並びに部品点数の削減が図られる。
【００３４】
本発明の各部構成は上記実施の形態に限らず、特許請求の範囲に記載の技術的範囲内で種々の変形が可能である。例えば、上記実施例の構造における正負の極性を逆転させた構成、即ち巻き取り電極体（４）を上下反転させて電池缶（５）内に収容すると共に、負極端子（８）を正極端子に変更し、電池缶（５）によって負極端部を形成する構成として、本発明を実施することも可能である。
【図面の簡単な説明】
【図１】本発明に係るリチウムイオン二次電池の断面図である。
【図２】巻き取り電極体の一部展開斜視図である。
【図３】負極端子機構の分解斜視図である。
【図４】連結片を具えた負極側集電板の斜視図である。
【図５】他形状の連結片を具えた負極側集電板の斜視図である。
【図６】負極側の集電板を負極端子機構に連結する工程を示す一部破断正面図である。
【図７】負極側の集電板を負極端子機構に連結した構造を示す一部破断正面図である。
【図８】下方の蓋体と端子連結部材の間の溶接構造を示す斜視図である。
【図９】正極側の集電板、及び該集電板に端子連結部材を固定した状態を示す斜視図である。
【図１０】端子連結部材を電池缶の蓋体に連結する工程を示す一部破断正面図である。
【図１１】２本の本発明電池を直列に接続した状態を示す断面図である。
【図１２】電池缶の蓋体に対しクラッド接合構造を有する接続補助板を固定した構成例を示す断面図である。
【図１３】従来のリチウムイオン二次電池の断面図である。
【図１４】２本の従来電池を直列に接続した状態を示す断面図である。
【符号の説明】
（５）　電池缶
（５１）　筒体
（５２）　蓋体
（５３）　蓋体
（４）　巻き取り電極体
（６）　集電板
（６１）　集電板
（６２）　円弧状凸部
（６３）　連結片
（６４）　連結片
（７）　負極端子機構
（７１）　端子接続部材
（７０）　スカート部
（７２）　第１絶縁部材
（７３）　第２絶縁部材
（７６）　リベット部材
（８）　負極端子
（８１）　ニッケル層
（８２）　アルミニウム層
（９）　端子連結部材
（９０）　溶接部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a non-aqueous electrolyte solution in which an electrode body serving as a power generation element is housed inside a cylindrical battery can, such as a lithium ion secondary battery, and electric power generated by the electrode body can be taken out. The present invention relates to a secondary battery and a manufacturing method thereof.
[0002]
[Prior art]
2. Description of the Related Art In recent years, lithium-ion secondary batteries with high energy density have attracted attention as power sources for portable electronic devices, electric vehicles, and the like. As shown in FIG. 13, for example, a cylindrical lithium ion secondary battery accommodates a wound electrode body (2) inside a positive electrode can (1), and a sealing plate ( 11) is fixed, and an insulating member (12) is interposed between the positive electrode can (1) and the sealing plate (11). Further, a negative electrode terminal (13) having a built-in gas discharge valve (14) is attached to the sealing plate (11).
[0003]
The wound electrode body (2) includes a strip-shaped negative electrode (21), a separator (22), and a positive electrode (23), and the negative electrode (21) and the positive electrode (23) are respectively placed on the separator (22) in the width direction. They are staggered and superimposed and wound in a spiral. Accordingly, at one end of the two ends in the axial direction of the winding electrode body (2), the edge of the negative electrode (21) projects outward from the edge of the separator (22), and the other end. The edge of the positive electrode (23) projects beyond the edge of the separator (22).
Current collecting plates (3) are provided at both ends of the wound electrode body (2). The current collector plate (3) on the negative electrode side is welded to the back surface of the sealing plate (11) via a tab (31), and the current collector plate (3) on the positive electrode side is connected to the positive electrode can (3) via the tab (31). It is welded to the bottom of 1).
Thereby, the electric power generated by the winding electrode body (2) can be taken out from the negative electrode terminal (13) and the positive electrode can (1) to the outside.
The negative electrode terminal (13) is formed of nickel, copper, or stainless steel stable at the negative electrode potential, and the positive electrode can (1) is formed of aluminum or aluminum alloy stable at the positive electrode potential.
[0004]
In the lithium ion secondary battery, a required output voltage is obtained by connecting a plurality of batteries A and B in series as shown in FIG.
[0005]
[Problems to be solved by the invention]
However, the conventional lithium ion secondary battery shown in FIG. 13 has a connection structure using a tab (31) for connecting the positive electrode of the wound electrode body (2) and the bottom wall of the positive electrode can (1). As a result, the current path length between the take-up electrode body (2) and the positive electrode can (1) is large, thereby increasing the internal resistance and the dead space due to the arrangement of the tab (31). As a result, the volume efficiency of the battery decreases. Furthermore, the work of welding the tip of the tab (31) to the bottom surface of the positive electrode can (1) is complicated, and there is a problem that productivity is poor.
Accordingly, an object of the present invention is to provide a non-aqueous electrolyte secondary battery capable of simultaneously reducing internal resistance, increasing volumetric efficiency, and improving productivity, and a method for manufacturing the same.
[0006]
[Means for solving the problem]
The non-aqueous electrolyte secondary battery according to the present invention has a structure in which an electrode body is accommodated in a cylindrical battery can, and power generated by the electrode body can be taken out from a pair of positive and negative electrode terminals. A bottom wall forming one end of the battery can forms one electrode terminal, and a current collector plate is joined to one electrode edge of the electrode body.
A terminal connecting portion is protruded from a surface of the current collector plate opposite to the electrode body, and the terminal connecting portion is fitted tightly into a hole formed in a bottom wall of the battery can, and is provided outside the battery can. The battery can and the terminal connecting portion are made of the same material at the joint of each other, and are welded to the joint from the outside of the battery can.
[0007]
In the non-aqueous electrolyte secondary battery of the present invention, the terminal connecting portion protruding from the surface of the current collector plate is fitted into the hole formed in the bottom wall of the battery can, and the gap between the electrode body and the battery can is formed. Since the electrical connection is made, the length of the current path from the electrode body to the battery can is reduced as compared with the conventional tab connection, and the electric resistance of the current path is extremely low.
Also, since the terminal connecting portion protruding from the surface of the current collecting plate fits into the hole formed in the bottom wall of the battery can, most of the terminal connecting portion is buried in the bottom wall of the battery can. There is almost no dead space inside the battery can.
Furthermore, the welding portion between the terminal connecting portion and the bottom wall of the battery can is exposed outside the battery can, so that the welding operation can be performed from the outside of the battery can, thereby facilitating the welding operation. As a result, the reliability of welding is improved.
Since the battery can and the terminal connecting portion are made of the same material at the joining portion, there is no possibility that a defect occurs in welding to the joining portion, and high reliability can be obtained at the welding portion.
[0008]
In a specific configuration, the terminal connection portion has an outer peripheral surface having a cylindrical surface or a tapered surface, and a hole formed in the bottom wall of the battery can has an inner peripheral surface having a cylindrical surface or a tapered surface. The outer peripheral surface and the inner peripheral surface of the hole formed in the bottom wall of the battery can are in close contact with each other.
As a result, the contact area between the terminal connecting portion and the bottom wall of the battery can becomes sufficiently large, and the electric resistance of the current path is reduced.
[0009]
More specifically, the surface of the terminal connecting portion exposed from the bottom wall of the battery can is flush with or substantially flush with the surface of the bottom wall of the battery can, and the surface of the battery can bottom wall and the terminal connecting portion are aligned. The surface is formed with two recesses having a peripheral wall extending along the weld inside and outside the weld.
According to this specific configuration, the welded portion is sandwiched between the two peripheral walls, and the heat flow path when the heat of the welded portion dissipates toward the surroundings is narrowed. Heat dissipation is suppressed, and as a result, a situation in which the temperature of the welded portion rapidly decreases is avoided. Therefore, defects such as cracks do not occur in the welded portion.
[0010]
Further, a flat connection auxiliary plate (55) is fixed so as to cover the bottom surface of the battery can and the surface of the terminal connecting portion.
According to this specific configuration, the flat surface of the connection auxiliary plate (55) forms the electrode terminal portion. Therefore, for example, in the case where a plurality of batteries are connected in series, the electrode terminal portions of the other batteries will surely and stably contact the electrode terminal portions.
[0011]
The method for producing a nonaqueous electrolyte secondary battery according to the present invention,
Producing an electrode body;
A step of connecting a base end of a terminal mechanism to constitute one electrode terminal to one electrode edge of the manufactured electrode body,
A step of joining a current collector plate provided with a terminal connecting portion protruding toward a bottom wall of a battery can to constitute the other electrode end, for the other electrode edge of the manufactured electrode body,
The terminal connection portion is fitted into a hole formed in the bottom wall of the battery can to be exposed to the outside of the battery can, and is welded to the junction between the terminal connection portion and the bottom wall of the battery can from outside the battery can. Applying a
Sealing the battery can after injecting the non-aqueous electrolyte into the battery can.
[0012]
According to the method for manufacturing a non-aqueous electrolyte secondary battery of the present invention, it is possible to easily manufacture the non-aqueous electrolyte secondary battery of the present invention, thereby improving productivity. Can be done. In addition, since welding is performed from the outside of the battery can to the joint between the terminal connecting portion and the bottom wall of the battery can, the welding operation is easy, whereby reliable and highly reliable welding is realized, As a result, the internal resistance is reduced.
[0013]
【The invention's effect】
According to the non-aqueous electrolyte secondary battery and the method of manufacturing the same according to the present invention, it is possible to simultaneously reduce internal resistance, increase volumetric efficiency, and improve productivity.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment in which the present invention is applied to a lithium ion secondary battery will be specifically described with reference to the drawings.
Overall configuration As shown in FIG. 1, the lithium ion secondary battery according to the present invention is configured by housing a wound electrode body (4) inside a cylindrical battery can (5).
The battery can (5) is formed by welding and fixing lids (52) and (53) to both openings of a cylindrical tube (51), and the lower lid (53) forms a positive electrode terminal portion. ing. Further, a negative electrode terminal mechanism (7) is attached to the lid (52) above the battery can (5), and the negative electrode terminal part is formed by the negative electrode terminal (8) constituting the negative electrode terminal mechanism (7). Has formed.
As a result, it is possible to take out the generated power of the wound electrode body (4) from the positive electrode terminal portion and the negative electrode terminal portion.
The lid (52) above the battery can (5) is provided with a gas discharge valve (50) that releases pressure when the pressure inside the can increases.
[0015]
As shown in FIG. 2, the winding electrode body (4) has a strip-shaped separator (42) interposed between a strip-shaped negative electrode (41) and a strip-shaped positive electrode (43) and spirally winds them. Have been. The negative electrode (41) is formed by coating a negative electrode active material (44) containing a carbon material on both surfaces of a band-shaped core (45) made of copper foil, and the positive electrode (43) is made of a band-shaped core (45) made of aluminum foil. The positive electrode active material (46) made of a lithium composite oxide is applied to both surfaces of (47). The separator (42) is impregnated with a non-aqueous electrolyte.
The negative electrode (41) has a coated portion on which the negative electrode active material (44) is applied and a non-coated portion on which the negative electrode active material is not applied. The positive electrode (43) also has a coated portion on which the positive electrode active material (46) is applied and a non-coated portion on which the positive electrode active material is not applied.
[0016]
The negative electrode (41) and the positive electrode (43) are superimposed on the separator (42) so as to be shifted in the width direction, and the uncoated portions of the negative electrode (41) and the positive electrode (43) are separated from both end edges of the separator (42), respectively. Protrude outward. Then, these are spirally wound to form a wound electrode body (4). In the winding electrode body (4), at one end of both ends in the winding axis direction, the core edge (48) of the non-coated portion of the negative electrode (41) is connected to the separator (42). At the other end, the core edge (48) of the non-coated portion of the positive electrode (43) extends outward from the other edge of the separator (42). It is protruding.
[0017]
Current collecting structure As shown in FIG. 1, disc-shaped current collecting plates (6) and (61) are laser-welded to both ends of the wound electrode body (4).
The current collector plate (6) on the negative electrode side is made of nickel, copper, copper with a nickel-plated surface, or iron with a nickel-plated surface, and has a central hole (60) as shown in FIG. A plurality of (four in this embodiment) arc-shaped convex portions (62) extending radially around the central hole (60) are integrally molded with the plate-shaped main body, and the rear surface side, that is, the winding electrode body (4) side It protrudes.
On the surface of the current collector plate (6), four flat connecting pieces (each having a fan shape) are formed in four quarter circle regions sandwiched between two arc-shaped convex portions (62) and (62). 63) to (63) are arranged in a circle and fixed by welding. The outer peripheral surfaces of these four connecting pieces (63) to (63) form one cylindrical surface having a constant radius.
[0018]
The current collector plate (61) on the positive electrode side is made of aluminum or an aluminum alloy, and has a disk-shaped main body having a central hole (60) as shown in FIG. A plurality of (four in this embodiment) arc-shaped convex portions (62) extending radially are integrally molded and protrude on the rear surface side, that is, on the winding electrode body (4) side.
As shown in FIG. 9 (b), a disc-shaped aluminum terminal connecting member (9) is fixed to the surface of the current collecting plate (61) at a position closing the central hole (60). . A circular concave portion (91) is formed on the surface of the terminal connecting member (9).
Incidentally, the terminal connecting member (9) can be formed integrally with the current collector plate (61).
[0019]
In the step of welding the current collectors (6) and (61) to both ends of the winding electrode body (4), first, the current collectors (6) and (61) are wound around the core edge of the winding electrode body (4). Press (48). As a result, the arc-shaped protrusions (62) of the current collector plates (6) and (61) bite into the core body edge (48) of the winding electrode body (4), and the arc-shaped protrusions (62) and the core body A joining surface consisting of a cylindrical surface is formed between the edges (48). In this state, laser welding is performed by irradiating the inner peripheral surface of the arc-shaped convex portion (62) of the current collector plates (6) and (61) with a laser beam. As a result, the arc-shaped convex portion (62) of the current collector plate (6) and the core edge (48) of the winding electrode body (4) are joined to each other with a large contact area.
[0020]
Negative terminal connection structure The negative terminal mechanism (7) has a cylindrical shape to be welded to a plurality of connection pieces (63) on the current collector (6) as shown in FIGS. Terminal connecting member (71) having a skirt portion (70), first and second insulating members (72) and (73) to be attached to the center hole of the upper lid (52), and a terminal connecting member (71). ), A cylindrical rivet member (76) for fastening the insulating members (72) and (73) to the lid (52), a rubber stopper (79) for closing an opening of the rivet member (76), and the rubber A negative terminal (8) welded to the surface of the rivet member (76) over the plug (79).
Before the injection of the electrolyte, the negative electrode terminal mechanism (7) was assembled with the rubber stopper (79) and the negative electrode terminal (8) removed. After the electrolyte was injected, the rubber stopper (79) was attached to the rivet member (76). ) Is attached, and the negative electrode terminal (8) is fixed by welding to the surface of the rivet member (76).
[0021]
The terminal connection member (71) is formed of nickel, iron with a nickel-plated surface, copper with a nickel-plated surface, or stainless steel.
The first insulating member (72) has a substantially disk shape and is pressed against the back surface of the lid (52), and the second insulating member (73) has a generally cylindrical shape and has a central hole in the lid (52). It is press-bonded to the inner peripheral surface, and the airtightness between the lid (52) and the negative electrode terminal mechanism (7) is maintained by the insulating members (72) and (73). , A fluororesin (PFA, PTFE), PPS, or PEEK.
[0022]
The rivet member (76) is made of iron, nickel, copper, nickel-plated copper or soft iron with a nickel-plated surface, and a cylindrical portion (78) on the back surface of the disk portion (77) as shown in FIG. 6), and as shown in FIG. 6, a rivet member (76) is connected to the center opening of the terminal connecting member (71) and the insulating members (72) and (73) assembled to the lid (52). By crimping the lower end (78a) of the cylindrical portion (78) in a state where the cylindrical portion (78) is inserted, the terminal connecting member (71) and both insulating members (72) and (73) cover the lid ( 52).
[0023]
The negative electrode terminal (8) has a two-layer clad bonding structure of a nickel layer (81) having a thickness of about 0.2 mm and an aluminum layer (82) having a thickness of about 30 μm. In addition, in the clad bonding, besides a method of bonding two layers by rolling under a general reduced pressure, a method of forming a diffusion layer at a bonding interface between the two layers by rolling under heating or heating after rolling. Can be adopted.
Thus, the nickel layer (81) and the aluminum layer (82) are tightly integrated with each other. Therefore, there is no possibility that moisture or the like may enter the interface between the nickel layer (81) and the aluminum layer (82), thereby preventing electrical corrosion due to contact between different kinds of metals.
In addition, the joining of the nickel layer (81) and the aluminum layer (82) is not limited to the clad joining, and a method of forming an aluminum layer (82) by applying aluminum plating to the surface of the nickel layer (81) may be employed. Is also possible.
[0024]
The outer peripheral surfaces of the plurality of connecting pieces (63) provided on the current collecting plate (6) on the negative electrode side of the winding electrode body (4) are skirts of a terminal connecting member (71) constituting the negative electrode terminal mechanism (7). As shown in FIG. 6, the negative electrode terminal mechanism (7) can be attached to the lid (52) while the negative electrode terminal mechanism (7) can be attached to the winding electrode body (4). After fixing the current collecting plate (6) provided with the connecting piece (63), as shown in FIG. 7, the connection between the inner peripheral surface of the skirt portion (70) of the terminal connecting member (71) and the current collecting plate (6). The outer peripheral surface of the piece (63) is brought into close contact with the piece, and in this state, a laser beam is irradiated from the outside of the skirt (70) of the terminal connecting member (71) as shown by an arrow, and the skirt of the terminal connecting member (71) (70) and the connecting piece (63) of the current collector plate (6) are laser welded to each other.
[0025]
Incidentally, the four connecting pieces (63) to (63) can be integrally formed with the current collector plate (6). Also, instead of the fan-shaped connecting piece (63), an arc-shaped connecting piece (64) as shown in FIG. 5 is protruded from the current collector (6), and the outer peripheral surface of the plurality of connecting pieces (64). It is also possible to form a cylindrical surface to be in close contact with the inner peripheral surface of the skirt (70) of the terminal connecting member (71). Further, the connecting piece (64) can be formed by cutting and raising a part of the current collector plate (6).
[0026]
Terminal connection structure on the positive electrode side On the other hand, as shown in FIG. 1, the terminal connection member (9) fixed to the current collector (61) on the positive electrode side of the wound electrode body (4) includes a battery can (5). ) Is connected to the lid (53) below.
In the lid (53) below the battery can (5), a central hole (58) having an inner diameter matching the outer diameter of the terminal connecting member (9) is opened as shown in FIG. 9) is fitted into the center hole (58) of the lid (53), and the lid (53) is aligned with the surface of the lid (53) and the surface of the terminal connecting member (9) as shown in FIG. As shown in FIG. 8, a laser beam is applied to the joint of the terminal connecting member (9) from the outside of the lid (53) along a path along the circumferential line to perform laser welding (90). As a result, the terminal connecting member (9) is fixed to the lid (53).
[0027]
In the above terminal connection structure, a peripheral wall located inside the welded portion (90) is formed on the surface of the terminal connection member (9) by the recess (91), and the surface of the lid (53) is formed on the surface of the lid (53). The groove (54) extending along the circumferential line is recessed, and a peripheral wall located outside the welded portion (90) is formed.
As a result, the welded portion (90) is sandwiched between the two peripheral walls, and heat dissipation during laser welding is suppressed, so that a situation in which the temperature of the welded portion (90) sharply decreases is avoided. Therefore, cracks and other defects do not occur in the welded portion (90).
[0028]
A connection auxiliary plate (55a) made of aluminum is laser-welded to the surface of the lid (53) below the battery can (5) as necessary, as shown in FIG. ) Forms a flat surface positive electrode terminal portion.
Thus, when two batteries A and B are connected in series as shown in FIG. 11, the negative terminal (8b), which is the negative terminal of one battery B, is connected to the positive terminal of the other battery A. It is possible to reliably and stably contact the auxiliary plate (55a).
[0029]
Battery assembling method After the wound electrode body (4) shown in FIG. 2 is manufactured, the current collector plate (6) shown in FIG. 4 is laser-welded to the negative electrode edge of the wound electrode body (4). And a current collector plate (61) shown in FIG. 9B is joined to the positive electrode edge of the wound electrode body (4) by laser welding.
Next, as shown in FIG. 6 and FIG. 7, after the rubber plug (79) and the negative electrode terminal mechanism (7) other than the negative electrode terminal (8) are assembled to the lid (52), the current collector plate (6) is assembled. ) Is welded to the skirt portion (70) of the terminal connecting member (71). The welding is performed by irradiating a laser beam from outside the skirt portion (70) of the terminal connecting member (71).
Thereafter, as shown in FIG. 10, the terminal connecting member (9) on the current collector (61) is fitted into the central hole (58) of the lid (53) of the battery can (5), and the terminal connecting member (9) is inserted. Is exposed to the surface of the lid (53). Then, welding is performed from the outside of the battery can (5) to the joint between the terminal connecting member (9) and the lid (53).
Finally, after injecting the electrolyte into the inside of the battery can (5) from the center hole of the rivet member (76) of the negative electrode terminal mechanism (7), a rubber stopper (79) is attached to the opening of the rivet member (76). Further, the negative electrode terminal (8) is welded to the surface of the rivet member (76) to seal the battery can (5) as shown in FIG.
[0030]
In the lithium ion secondary battery of the present invention, since the negative electrode terminal (8) has a clad bonding structure of the nickel layer (81) and the aluminum layer (82), as shown in FIG. , B are connected in series, the aluminum layer (82) of the negative electrode terminal (8b) of one battery B and the aluminum connection auxiliary plate (55a) of the other battery A come into contact with each other, and different metals are connected. No electrical corrosion occurs due to the contact of the metal. Further, even in a configuration in which the connection auxiliary plate (55) is omitted, the aluminum layer (82) of the negative electrode terminal (8b) of one battery B and the aluminum lid (53a) or the aluminum terminal connecting member of the other battery A Since (9a) is in contact, no electrical corrosion occurs due to contact between dissimilar metals.
[0031]
Instead of the negative electrode terminal (8) having a clad bonding structure of a nickel layer (81) and an aluminum layer (82), a connection auxiliary plate (55) is replaced with an aluminum layer (56) and a nickel layer as shown in FIG. Even in the case of adopting the structure having the clad bonding structure of (57), the same metal is brought into contact with each other, and electric corrosion due to the contact between different metals is not generated.
[0032]
Further, in the lithium ion secondary battery of the present invention, the connecting piece (63) fixed to the current collector plate (6) on the negative electrode side has a structure for connecting the wound electrode body (4) to the negative electrode terminal mechanism (7). ) And the skirt portion (70) of the terminal connecting member (71) constituting the negative electrode terminal mechanism (7) are directly joined to each other without using a tab as in the related art, thereby improving productivity. Improvement, shortening of the current path length between the wound electrode body (4) and the negative electrode terminal (8), reduction of dead space in the battery can (5), and reduction of internal resistance are achieved.
[0033]
Furthermore, in the above-mentioned lithium ion secondary battery of the present invention, the structure in which the winding electrode body (4) is connected to the lid (53) of the battery can (5) serving as a positive electrode terminal portion has a structure in which the winding electrode body (4) is connected. After connecting the negative electrode terminal mechanism (7) to 4), the terminal connecting member (9) fixed to the current collector plate (61) on the positive electrode side is fitted into the central hole (58) formed in the lid (53). In short, by adopting a structure in which the terminal connecting member (9) and the lid (53) are directly joined without interposing a tab as in the conventional case, productivity by enabling laser welding from outside the can is achieved. , The length of the current path between the winding electrode body (4) and the lid body (53), the internal resistance, and the number of parts are reduced.
[0034]
The configuration of each part of the present invention is not limited to the above embodiment, and various modifications can be made within the technical scope described in the claims. For example, a configuration in which the positive and negative polarities in the structure of the above embodiment are reversed, that is, the wound electrode body (4) is turned upside down and accommodated in the battery can (5), and the negative electrode terminal (8) is used as the positive electrode terminal. Alternatively, the present invention can be implemented as a configuration in which the negative electrode end is formed by the battery can (5).
[Brief description of the drawings]
FIG. 1 is a sectional view of a lithium ion secondary battery according to the present invention.
FIG. 2 is a partially developed perspective view of a wound electrode body.
FIG. 3 is an exploded perspective view of a negative electrode terminal mechanism.
FIG. 4 is a perspective view of a negative-electrode-side current collector provided with a connecting piece;
FIG. 5 is a perspective view of a negative-electrode-side current collector plate having a connection piece of another shape.
FIG. 6 is a partially broken front view showing a step of connecting a current collector plate on the negative electrode side to a negative electrode terminal mechanism.
FIG. 7 is a partially cutaway front view showing a structure in which a current collector on the negative electrode side is connected to a negative electrode terminal mechanism.
FIG. 8 is a perspective view showing a welding structure between a lower lid and a terminal connecting member.
FIG. 9 is a perspective view showing a current collecting plate on the positive electrode side and a state where a terminal connecting member is fixed to the current collecting plate.
FIG. 10 is a partially broken front view showing a step of connecting a terminal connecting member to a lid of a battery can.
FIG. 11 is a cross-sectional view showing a state where two batteries of the present invention are connected in series.
FIG. 12 is a cross-sectional view showing a configuration example in which a connection auxiliary plate having a clad bonding structure is fixed to a lid of a battery can.
FIG. 13 is a sectional view of a conventional lithium ion secondary battery.
FIG. 14 is a cross-sectional view showing a state in which two conventional batteries are connected in series.
[Explanation of symbols]
(5) Battery can (51) Cylindrical body (52) Lid (53) Lid (4) Winding electrode (6) Current collector (61) Current collector (62) Arc-shaped convex part (63) Connection Piece (64) connecting piece (7) negative electrode terminal mechanism (71) terminal connecting member (70) skirt portion (72) first insulating member (73) second insulating member (76) rivet member (8) negative electrode terminal (81) Nickel layer (82) Aluminum layer (9) Terminal connecting member (90) Welded part

Claims

Inside the cylindrical battery can, an electrode body in which a separator containing a non-aqueous electrolyte is interposed between a strip-shaped positive electrode and a strip-shaped negative electrode is housed, and the power generated by the electrode body is stored in the battery can. In a non-aqueous electrolyte secondary battery that can be taken out from a pair of positive and negative electrode terminals provided at both ends in the cylinder axis direction, one electrode terminal is formed by a bottom wall forming one end of a battery can. Is formed, a current collecting plate is joined to one electrode edge of the electrode body, and a terminal connecting portion is protruded from a surface of the current collecting plate opposite to the electrode body, and the terminal connecting portion is The battery can and the terminal connecting portion are fitted into the hole formed in the bottom wall of the battery can tightly, and are exposed to the outside of the battery can. A non-aqueous electrolyte secondary battery characterized in that welding is performed on the joining portion.

The terminal connecting portion has an outer peripheral surface having a cylindrical surface or a tapered surface, and a hole formed in the bottom wall of the battery can has an inner peripheral surface having a cylindrical surface or a tapered surface. The non-aqueous electrolyte secondary battery according to claim 1, wherein an inner peripheral surface of a hole formed in a bottom wall of the non-aqueous electrolyte is in close contact with each other.

The surface of the terminal connecting portion exposed from the bottom wall of the battery can is flush with or substantially flush with the surface of the bottom wall of the battery can. 3. The nonaqueous electrolyte secondary battery according to claim 1, wherein two concave portions having a peripheral wall extending along the welded portion inside and outside the portion are formed. 4.

The non-aqueous electrolyte secondary battery according to any one of claims 1 to 3, wherein a flat connection auxiliary plate (55) is fixed so as to cover a bottom surface of the battery can and a surface of the terminal connecting portion.

Inside the cylindrical battery can, an electrode body in which a separator containing a non-aqueous electrolyte is interposed between a strip-shaped positive electrode and a strip-shaped negative electrode is housed, and the power generated by the electrode body is stored in the battery can. In a method for manufacturing a non-aqueous electrolyte secondary battery that can be taken out from a pair of positive and negative electrode terminals provided at both ends in the cylinder axis direction of
Producing an electrode body;
A step of connecting a base end of a terminal mechanism to constitute one electrode terminal to one electrode edge of the manufactured electrode body,
A step of joining a current collector plate provided with a terminal connecting portion protruding toward a bottom wall of a battery can to constitute the other electrode end, for the other electrode edge of the manufactured electrode body,
The terminal connection portion is fitted into a hole formed in the bottom wall of the battery can to be exposed to the outside of the battery can, and is welded to the junction between the terminal connection portion and the bottom wall of the battery can from outside the battery can. Applying a
After injecting the non-aqueous electrolyte into the battery can, sealing the battery can.