JP2004327291A - Nonaqueous electrolyte battery - Google Patents

Nonaqueous electrolyte battery Download PDF

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Publication number
JP2004327291A
JP2004327291A JP2003121844A JP2003121844A JP2004327291A JP 2004327291 A JP2004327291 A JP 2004327291A JP 2003121844 A JP2003121844 A JP 2003121844A JP 2003121844 A JP2003121844 A JP 2003121844A JP 2004327291 A JP2004327291 A JP 2004327291A
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positive electrode
winding
wound
sheet
electrode
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JP4079326B2 (en
Inventor
Tetsuo Kawai
徹夫 川合
Toshiyuki Edamoto
俊之 枝元
Reiko Masukichi
令子 益吉
Mitsutoshi Watanabe
光俊 渡辺
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Maxell Holdings Ltd
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Hitachi Maxell 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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  • Battery Electrode And Active Subsutance (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To enhance safety and reliability by suppressing the occurrence of short-circuiting caused when the end face edge part of a winding end part of a positive electrode sheet damages a separator, in a nonaqueous electrolyte battery having an electrode winding body formed by winding a short and thick positive electrode like a sheet together with a negative electrode and a separator as a battery element. <P>SOLUTION: Two positive electrode sheets 20, 21 composing the positive electrode 3 are wound so that their winding end parts E are brought under an uneven and dislocated condition. Since the outwardly stretched width of the winding end part E of the positive electrode 21 on the outer periphery side can be suppressed small by providing a level difference between the positive electrode sheets 20, 21, a damage of a separator 5 which is caused when the edge part 21a of the winding end part E of the positive electrode sheet 21 on the outer periphery side greatly stretches outward, and which has been unavoidable when both positive electrode sheets 20, 21 are made even without dislocating them, is eliminated to prevent short-circuiting from being caused. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、非水電解液電池に関し、さらに詳しくは、中負荷以下の用途に適した高容量かつ安全で信頼性の高い円筒形の非水電解液電池に関する。
【０００２】
【従来の技術】
筒形の非水電池には、メモリーバックなどの高容量ではあるが軽負荷用のボビンタイプの電池と、カメラの電源など重負荷対応の捲回式電池とが広く知られている。前者のボビンタイプの電池は、ＣＲやＥＲ電池が製品化されているが、構造が簡単で低コストでの製造が可能であり、多くの活物質を充填することができる反面、電極面積が小さく負荷特性に劣ることから、大きな電流での放電を行おうとすると、容量が低下する不利がある。
【０００３】
後者の重負荷特性の捲回式電池は、ＣＲやＢＲの構成で製品化されている。この種の電池は、薄い長尺の電極を捲回してなる渦巻電極体を電池要素とするため、大きな電極面積を確保でき、大電流で放電しても大きな容量を取り出すことができる。但し、電池特性向上に直接的に寄与しないセパレータや集電体を電極体内に多く備えるため、活物質の充填量が低くならざるを得ず、電池容量が低下することは避けられない。また、大電流が取り出せる反面、短絡等の異常が起こった場合には発熱が激しく、発火の危険性があり、種々の安全対策が必要で、電池構造が複雑で製造コストの上昇を招く不利もある。
【０００４】
最近の応用機器の多様化により、メモリーバックなどの軽負荷用途、カメラ用などの重負荷用途だけでなく、データの発信、受信など中負荷での用途が増加しつつあり、中負荷で特徴を発揮する電池の開発が要望されていた。そこで、特許文献１および２には、厚い電極を数回巻いた電極捲回体を電池要素とする電池が提案されている。かかる電極捲回体を電池要素とする電池によれば、厚い電極を用いることで、従来の重負荷特性の電池に比べて、セパレータや集電体などの使用量を減らして活物質の充填性の向上を図ることができ、従って高容量な電池を得ることができる点で有利である。また、極端な大電流を流せなくすることで、安全性、信頼性に優れ、中負荷特性に優れた電池を得ることができる。
【０００５】
【特許文献１】
特開平６−２６７５８３号公報（段落番号００１７、図１、図３）
【特許文献２】
特開平９−１９０８３６号公報（段落番号００１９、図１）
【０００６】
【発明が解決しようとする課題】
但し、特許文献１および特許文献２に記載の電池の正極は、ニッケル発泡体からなる集電体の空隙に活物質合剤を充填してなる形態を採るため、可撓性や柔軟性に乏しい。このため厚み寸法を大きくとると、捲回時に電極の割れや切断、活物質の脱落が生じて短絡や導電不良を生じやすい不利がある。
【０００７】
そこで本発明者等は図７に示すごとく、正極３を、正極活物質をシート状に成形してなる２枚の正極シート２０・２１と、これら正極シート２０・２１の間に介在された集電体２２とからなるものとし、これらを捲回して電極捲回体６を作製した。そこでは、電極捲回体６の作成時において、正極シート２０・２１と集電体２２とを捲回始端部Ｓのみを固定した状態で捲回するようにした。これによれば、正極３を２枚の正極シート２０・２１に分割することで、発泡金属製の集電体の空隙に活物質を充填してなる従来形態に比べて、正極３の可撓性や柔軟性の向上を図ることができるため、捲回時における正極３の割れや切断、活物質の脱落などの発生を効果的に解消できる。
【０００８】
但し、図７に示すごとく、捲回末端部Ｅにおける２枚の正極シート２０・２１が揃っていると、外周側の正極シート２１の捲回末端部Ｅが外方向に大きく張り出すために、電極捲回体６を円筒状の外装缶２内に挿入する際に、捲回末端部Ｅに係る外周側の正極シート２１の端面エッジ部２１ａがセパレータ５を損傷して、短絡を引き起こしやすい。
【０００９】
本発明の目的は、厚み寸法が大きく且つ短いシート状の正極を、負極およびセパレータとともに捲回してなる電極捲回体を電池要素とする非水電解液電池において、正極シートの捲回末端部の端面エッジ部がセパレータを損傷することに起因する短絡の発生を抑えて、安全性、信頼性に優れる非水電解液電池を得ることにある。
【００１０】
【課題を解決するための手段】
本発明は、図２に示すごとく、上方開口部を有する有底円筒状の外装缶２内に、シート状の正極３と負極４とをセパレータ５を介して捲回してなる電極捲回体６と、非水電解液とを収容してなる円筒形の非水電解液電池を対象とする。図１および図４に示すごとく、電極捲回体６は、正極３の捲回始端部Ｓと捲回末端部Ｅとで規定される捲回数が１．６周以上、２．５周以下となるように正負極３・４およびセパレータ５を捲回してなるものであって、全体として略円柱形状に成形されている。正極３は、同一の厚み寸法を有する２枚の正極シート２０・２１と、これら正極シート２０・２１の間に介在された集電体２２とを含み、電極捲回体６の作成時において、該正極シート２０・２１と集電体２２は、捲回始端部Ｓのみを固定した状態で捲回する。各正極シート２０・２１は、正極活物質を０．５ｍｍ以上、２ｍｍ以下の厚み寸法を有するシート状に成形してなるものである。
【００１１】
そのうえで、請求項１記載の本発明は、図１および図４に示すごとく、電極捲回体６の最外周において、正極３を構成する２枚の正極シート２０・２１は、その捲回末端部Ｅが不揃いの位置ずれ状態とされており、両正極シート２０・２１の捲回末端部Ｅのずれ幅Ｗが、正極シート２０・２１の厚み寸法Ｌの１／２以上、２倍以下に設定されていることを特徴とする。
【００１２】
図１に示すごとく、電極捲回体６の最外周において、内周側に位置する正極シート２０の捲回末端部Ｅが、外周側に位置する正極シート２１の捲回末端部Ｅよりも長く延出された位置ずれ状態にあることがより好ましい。
【００１３】
また本発明は、図２に示すごとく、上方開口部を有する有底円筒状の外装缶２内に、シート状の正極３と負極４とをセパレータ５を介して捲回してなる電極捲回体６と、非水電解液とを収容してなる円筒形の非水電解液電池を対象とする。電極捲回体６は、図５に示すごとく、正極３の捲回始端部Ｓと捲回末端部Ｅとで規定される捲回数が１．６周以上、２．５周以下となるように正負極３・４およびセパレータ５を捲回してなるものであって、全体として略円柱形状に成形されている。正極３は、同一の厚み寸法を有する２枚の正極シート２０・２１と、これら正極シート２０・２１の間に介在された集電体２２とを含み、電極捲回体６の作成時において、該正極シート２０・２１と集電体２２は、捲回始端部Ｓのみを固定した状態で捲回する。各正極シート２０・２１は、正極活物質を０．５ｍｍ以上、２ｍｍ以下の厚み寸法を有するシート状に成形してなるものである。
【００１４】
そのうえで、請求項３記載の本発明は、図５に示すごとく、電極捲回体６の最外周において、外周側に位置する正極シート２１の捲回末端部Ｅに、他よりも厚みの薄い薄肉部２７を形成してあることを特徴とする。
【００１５】
また本発明は、図２に示すごとく、上方開口部を有する有底円筒状の外装缶２内に、シート状の正極３と負極４とをセパレータ５を介して捲回してなる電極捲回体６と、非水電解液とを収容してなる円筒形の非水電解液電池を対象とする。電極捲回体６は、図６に示すごとく、正極３の捲回始端部Ｓと捲回末端部Ｅとで規定される捲回数が１．６周以上、２．５周以下となるように正負極３・４およびセパレータ５を捲回してなるものであって、全体として略円柱形状に成形されている。正極３は、同一の厚み寸法を有する２枚の正極シート２０・２１と、これら正極シート２０・２１の間に介在された集電体２２とを含み、電極捲回体６の作成時において、該正極シート２０・２１と集電体２２は、捲回始端部Ｓのみを固定した状態で捲回する。各正極シート２０・２１は、正極活物質を０．５ｍｍ以上、２ｍｍ以下の厚み寸法を有するシート状に成形してなるものである。
【００１６】
そのうえで、請求項４記載の本発明は、図６に示すごとく、前記電極捲回体６の最外周において、外周側に位置する正極シート２１の捲回末端部Ｅの外側縁が、面取り形成されていることを特徴とする。
【００１７】
【発明の作用効果】
薄く且つ長いシート状の正・負極をセパレータを介して捲回してなる渦巻状の電極体を電池要素とする電池においては、正・負極の厚み寸法は極めて小さいため、電極体を円柱状に成形することは容易である。つまり、正・負極の捲回末端部の外方向への張り出し幅は、無視できるほどに僅かであるため、円筒状の外装缶内へ電極体を装填する際に捲回末端部を無理込むような事態は生じず、捲回末端部に係るセパレータが正・負極で損傷されて、短絡を起こすような不具合は生じない。
【００１８】
これに対して、本発明に係る非水電解液電池のごとく、厚み寸法が大きく、且つ長さ寸法の小さな正極を捲回してなる電極捲回体を電池要素とする場合には、電極捲回体を円柱状に成形することが難しく、正・負極の捲回末端部の外方向への張り出し幅が、外装缶内へ装填する際の問題となる。すなわち、図５に示すごとく、正極シート２０・２１の捲回末端部Ｅが揃っていて、該正極３の捲回末端部Ｅが外方向へ不用意に大きく張り出した形態となっていると、円筒状の外装缶２内へ電極体６を装填する際に、捲回末端部Ｅを無理込まなければならず、その結果、捲回末端部Ｅに係るセパレータ５が外周側に位置する正極シート２１のエッジ部２１ａで損傷されて、短絡が生じるおそれがある。
【００１９】
そこで本発明の非水電解液電池においては、図１および図４に示すごとく、正極３を構成する２枚の正極シート２０・２１を、その捲回末端部Ｅが不揃いの位置ずれ状態となるようにしてある。このように、正極シート２０・２１に段差を設けることで、外周側の正極シート２１の捲回末端部Ｅの外方向への張り出し幅を小さく抑えることができるので、図７に示すごとく両正極シート２０・２１を位置ずれさせずに揃えた場合に不可避であった、外周側の正極シート２１の捲回末端部Ｅのエッジ部２１ａが外方向に大きく張り出すことに起因するセパレータ５の損傷を解消でき、短絡の発生を効果的に防ぐことができる。とくに、図１に示すように、内周側に位置する正極シート２０の捲回末端部Ｅを、外周側に位置する正極シート２１の捲回末端部Ｅよりも長く延出してあると、外装缶２の内部スペースを無駄なく有効利用できるので、デッドスペースを最小限に抑えて、放電容量の向上が期待できる。
【００２０】
そのうえで、両正極シート２０・２１の捲回末端部Ｅのずれ幅Ｗは、正極シートの厚み寸法Ｌの１／２以上、２倍以下に、より好ましくは０．７以上、１．５倍以下に設定する。ずれ幅Ｗが正極シートの厚み寸法Ｌの１／２未満となると、正極シート２０・２１をずらした効果が得られず、外装缶２への電極捲回体６の装填時に、セパレータ５を傷つけて短絡を引き起こすおそれがある。ずれ幅Ｗが正極シート２０・２１の厚み寸法Ｌの２倍を超えると、集電体２２が正極シート２０・２１の捲回末端部Ｅから突出して、短絡を引き起こすおそれがある。また、集電体２２の片面に正極シート２０・２１がない部分の密着性が劣るため、中負荷での電池特性（放電容量）が低下する。
【００２１】
図５に示すごとく、電極捲回体６の最外周において、外周側に位置する正極シート２１の捲回末端部Ｅに、他よりも厚みの薄い薄肉部２７を形成してあると、捲回末端部Ｅに係る外周側の正極シート２１とセパレータ５との接触を抑えることができるので、セパレータ５の損傷に起因する短絡の発生を抑えることができる。
【００２２】
図６に示すごとく、前記電極捲回体６の最外周において、外周側に位置する正極シート２１の捲回末端部Ｅの外側縁を面取り形成して、正極シート２１の捲回末端部Ｅに係る外周側のエッジ部を削ってあると、セパレータ５の損傷を確実に抑えて、短絡の発生をよく防ぐことができる。
【００２３】
【発明の実施の形態】
（第１実施形態） 図１ないし図３に、本発明の第１実施形態に係る非水電解液電池を示す。図２において、非水電解液電池１は、上方開口部を有する有底円筒状の外装缶２と、外装缶２内に装填された正極３および負極４と、外装缶２の上方開口部を封止する封口構造とからなる。正極３および負極４は、セパレータ５を介して捲回してなる電極捲回体６として、電解液とともに外装缶２内に収容されている。外装缶２は、鉄やステンレスを素材とする。
【００２４】
封口構造は、外装缶２の上方開口部の内周縁に固定された蓋板８と、蓋板８の中央部に開設された開口に、ゴム製の絶縁パッキン９を介して装着された端子体１０と、蓋板８の下部に配置された絶縁板１１とからなる。絶縁板１１は、円盤状のベース部１２の周縁に環状の側壁１３を立設した上向きに開口する丸皿形状に形成されており、ベース部１２の中央にはガス通口１４が開設されている。蓋板８は、側壁１３の上端部に受け止められた状態で、外装缶２の上方開口部の内周縁に、レーザ溶接若しくはパッキングを介したクリンプシールで固定されている。蓋板８もしくは外装缶２の缶底２ａには薄肉部を設け、内圧が急激に上昇したときの対策としてのベントを設けることができる。正極３と端子体１０の下面とは、正極リード体１５で接続されており、負極端子４と外装缶２の内面とは負極リード体１６で接続されている。
【００２５】
図１に示すごとく、電極捲回体６は、正極３の捲回始端部Ｓと捲回末端部Ｅとで規定される捲回数が、１．６周以上、２．５周以下となるように正・負極３・４およびセパレータ５を捲回してなるものであって、全体として略円柱形状に形成される。なお、図１には捲回数が１．６周程度の形態を示す。正極３は、同一の厚み寸法を有する２枚の正極シート２０・２１と、これら正極シート２０・２１の間に介在された集電体２２とを含み、電極捲回体６の作成時においては、正極シート２０・２１と集電体２２は、捲回始端部Ｓのみを固定した状態で捲回される（図３（ｃ）参照）。
【００２６】
正極シート２０・２１は、正極活物質を０．５ｍｍ以上、２ｍｍ以下の厚み寸法Ｌを有するシート状に成形してなる。正極活物質としては、例えば二酸化マンガン、フッ化カーボン、リチウムコバルト複合酸化物、スピネル形リチウムマンガン複合酸化物などを挙げることができる。
【００２７】
正極３の電導助剤としては、黒鉛、カーボンブラック、アセチレンブラック、ケッチェンブラックから選択される一種、または２種以上の複合物を用いることができるが、主成分としてケッチェンブラックを用いることが好ましい。正極３のバインダとしては、テフロンディスパージョンや、粉末のテフロン（登録商標）、ゴム系バインダなどを用いることができるが、テフロンディスパージョンを用いることが好ましい。
【００２８】
正極リード体１５としては、ステンレス３１６や、４３０、４４４などからなる平織り金網、エキスパンドメタル、ラス網、パンチングメタル、箔などを用いることができる。
【００２９】
負極４は、薄い板状（箔状）に形成されており、その材料としては、リチウム金属、リチウムとアルミニウムなどの合金、黒鉛などの炭素材料を挙げることができる。負極４は、図１および図３（ｂ）に示すごとく、短尺と長尺の２枚の負極４ａ・４ｂを、張り合わしてなるものであり、これらを正極３、セパレータ５とともに捲回して電極捲回体６を作製する。負極リード体１６としては、ニッケルリボン、ステンレス平織り金網、エキスパンドメタル、ラス網、パンチングメタルなどを用いることができる。
【００３０】
電解液としては、溶質としてＬｉＰＦ６ 、ＬｉＣｌＯ４ 、ＬｉＣＦ３ ＳＯ３ 、（ＣＦ３ ＳＯ２ ）２ ＮＬｉなどを０．３〜１．５Ｍ／ｌ溶解した溶媒として、ＰＣ、ＥＣなどの環状カルボネートにＤＭＥなどの鎖状エーテル、ジメチルカルボネートなどの鎖状カルボネートを混合した電解液が用いられる。
【００３１】
セパレータ５としては、ＰＰ、ＰＥ、ＰＥＴ、ＰＢＴ、ＰＰＳなどの不織布、微孔性フィルムなどを用いることができる。
【００３２】
電極捲回体は、図３に示すような手順で作製することができる。まず、図３（ａ）に示すごとく、セパレータ５を２つ割の巻芯２５に挟んで１周巻く。次に、図３（ｂ）に示すごとく、負極４を短尺４ａのみの一層部分から巻芯２５に向けて挿入して、セパレータ５とともに１周巻き込む（図３（ｃ）参照）。続いて、図３（ｃ）に示すごとく、正極３をセパレータ５を介して負極４上に載置して巻芯２５で捲回する。ここでは、正極３は、両正極シート２０・２１および集電体２２を固定した巻始端Ｓの側から捲回されるようにしてあり、長尺の負極４ｂ上にセパレータ５を介して載置された状態で捲回される。捲回終了後は、セパレータ５が最外周を覆う形となり、このセパレータ５の捲回末端部Ｅを固定テープで固定する。以上より、図１に示すような形態の電極捲回体６を得ることができる。
【００３３】
内外周に位置する２枚の正極シート２０・２１の長さ寸法を調整することで、捲回末端部Ｅに係る正極３の形態を適宜に変化させることができる。ここでは、図１に示すごとく、捲回末端部Ｅに係る内周側の正極シート２０が、外周側の正極シート２１よりも長く延出された、両正極シート２０・２１が不揃いの位置ずれ状態となるように、両正極シート２０・２１の長さ寸法を調整してある。これにより、外周側の正極シート２１の捲回末端部Ｅの外方向への張り出し幅を小さく抑えることができるので、図７に示すごとく両正極シート２０・２１を位置ずれさせずに揃えた形態では不可避であった、外周側の正極シート２１の捲回末端部Ｅのエッジ部が外方向に大きく張り出すことに起因するセパレータ５の損傷を抑えて、短絡の発生を効果的に防ぐことができる。すなわち、外周側の正極シート２１の捲回末端部Ｅの外方向への張り出し幅を小さく抑えることにより、電極捲回体６の外装缶２内への装填時に、正極シート２１の捲回末端部Ｅのエッジ部２１ａと外装缶２の内周面とが強く擦れて、介在するセパレータ５が損傷されることをよく防ぐことができる。
【００３４】
そのうえで、両正極シート２０・２１の捲回末端部Ｅのずれ幅Ｗは、正極シート２０・２１の厚み寸法Ｌの１／２以上、２倍以下に、より好ましくは、０．７以上、１．５倍以下に設定する。ずれ幅Ｗが正極シート２０・２１の厚み寸法の１／２未満となると、正極シート２０・２１をずらした効果が得られず、セパレータ５の損傷して短絡が生じやすい。ずれ幅Ｗが正極シート２０・２１の厚み寸法Ｌの２倍を超えると、集電体２２が正極シート２０・２１の捲回末端部Ｅから突出して、短絡を引き起こすおそれがある。また、集電体２２の片面に正極シート２０・２１がない部分の密着性が劣るため、中負荷での電池特性（放電容量）が低下する。
【００３５】
（第２実施形態） 図４に、本発明の第２実施形態に係る非水電解液電池を示す。この場合の非水電解液電池は、捲回末端部Ｅに係る内周側の正極シート２０が、外周側の正極シート２１よりも短くなっている点が、先の第１実施例と相違する。これによっても、外周側の正極シート２１の捲回末端部Ｅの外方向への張り出し幅を抑えることができるので、外装缶２への装填時におけるセパレータ５の損傷を抑えて、短絡の発生をよく防ぐことができる。
【００３６】
（第３実施形態） 図５に、本発明の第３実施形態に係る非水電解液電池を示す。この場合の非水電解液電池１は、両正極シート２０・２１の捲回末端部Ｅを、他よりも厚みの薄い薄肉部２７としてある点が、先の第１実施例と相違する。この薄肉部２７は、例えば、正極シート２０・２１の捲回末端部Ｅに対してプレス加工を施すことにより形成できる。このように正極シート２０・２１の捲回末端部Ｅに薄肉部２７を設けることで、捲回末端部Ｅに係る外周側の正極シート２１とセパレータ５との接触を抑えることができるので、セパレータ５の損傷に起因する短絡の発生を抑えることができる。なお、図５には、両正極シート２０・２１の捲回末端部Ｅに対して薄肉部２７を設けた例を示したが、外周側の正極シート２１のみに薄肉部２７を設けてもよい。
【００３７】
（第４実施形態） 図６に本発明の第４実施形態に係る非水電解液電池を示す。この場合の非水電解液電池１は、両正極シート２０・２１の捲回末端部Ｅに係る外周側のエッジ部を削って、Ｒ状に面取りしてある点が、先の第１実施例と相違する。図６において符号２８は、面取り部分を示す。これによっても、セパレータ５の損傷を抑えて、短絡の発生を効果的に防ぐことができる。なお、外周側の正極シート２１にのみ、面取り処理を行った形態であってもよい。
【００３８】
【実施例】
次に、実施例を挙げて本発明をより具体的に説明する。但し、本発明はこれら実施例に限定されるものではない。なお、この実施例においては、ＣＲ電池を例にして説明する。
【００３９】
《実施例１》
〈正極の製法〉
（配合） ケッチェンブラック３％と、二酸化マンガン（東ソー社製）９２％の比率でプラネタリーミキサーを用いて乾式で５分間混合したのち、水を重量比で固形分の２０％添加して５分間混合した。テフロンディスパージョン（Ｄ−１ダイキン工業社製）を固形分として５％を残りの水に希釈した状態で添加し、５分間混合した。配合剤中の水分は、固形分１００に対し２５〜３０に調整した。
【００４０】
（シート化） 混合した配合剤を直径２５０ｍｍの２本ロールを用い、ロール温度を１３０±５℃に調整し、プレス圧７トン／ｃｍ、ロール間隔０．４ｍｍ、回転速度１０ｒｐｍで、ロールによる圧延、シート化を行った。ロールを通過した配合剤（予備シート）を１０５℃±５℃で残水分が２％以下になるまで乾燥した。次いで乾燥後の予備シートを粉砕器を用いて粉砕した。ここでは、プレスされた予備シートが、元の見かけ体積の２倍以上になるまでコーヒーミルで粉砕した。粉砕された粒子径は、大部分が１ｍｍ以下であり、バインダとして添加したテフロン（登録商標）の繊維も１ｍｍ以下の長さに切断されていた。
【００４１】
粉砕された材料に対して、再度ロールによるシート化を行った。ロールの間隔は０．６±０．０５ｍｍに調整し、ロール温度は１２０±１０℃、プレス圧７トン／ｃｍ、回転速度１０ｒｐｍでシート化を行い、正極シートを得た。正極シートは、厚さが１．０ｍｍ、密度が２．６ｇ／ｃｍ３ であった。
【００４２】
以上のようにして、内周用と外周用の２枚の正極シート２０・２１（図１、図３（ｃ）参照）を作成した。内周用の正極シート２０は、幅３７ｍｍ、長さ５１ｍｍに切断した。外周用の正極シート２１は、幅３７ｍｍ、長さ６２ｍｍに切断した。
【００４３】
（集電体） ステンレス３１６からなるラス網（日建ラス社製）を集電体２２として用いた。このラス網は、幅３５ｍｍ、長さ５６ｍｍに切断し、その長さ方向の中央部に、厚さ０．３ｍｍ、幅３ｍｍのステンレスリボン製の正極リード体１５を抵抗溶接により取り付けた。集電体２２にカーボンペースト（日本黒鉛社製）を網の目をつぶさない程度に塗布したのち、１０５℃±５℃の加熱温度条件で２時間以上乾燥した。尚、ここでは４ｍｇ／ｃｍ２ となるようにカーボンペーストを塗布した。
【００４４】
次に、図３（ｃ）に示すごとく、２枚の正極シート２０・２１を、その間に集電体２２を介装した状態で長さ方向の一端部のみを固定して三者を一体化した。具体的には、内・外周用の２枚の正極シート２０・２１は、長さ方向の一端を揃えるとともに、集電体２２の端部が正極シート２０・２１からはみ出さないようにセットし、その状態で長さ方向の端部から３〜１０ｍｍをプレスにより圧着することで、３者を一体化した。続いて、これら正極シート２０・２１および集電体２２を２５０℃±１０℃で６時間熱風乾燥して正極３を得た。尚、ここで正極シート２０・２１と集電体２２とを一体化したのは、作業上の問題であり、尤も独立した正極シート２０・２１と集電体２２とを、捲回時に一体化しても特性上の問題はない。
【００４５】
〈負極の製法〉
負極４は、幅３７ｍｍ、厚さ０．３ｍｍのリチウム箔を３６ｍｍと９６ｍｍに切断し、短尺側の箔４ａの一端から１０ｍｍを除き、３６ｍｍを長尺側の箔４ｂと重ねて圧着した。負極リード体１６は、厚さ０．１ｍｍ、幅３ｍｍのニッケルリボンの一端をエンボス加工してなるものとし、２枚の箔の間に挟んで圧着して固定した。
【００４６】
〈組立方法〉
幅４４ｍｍ、厚さ０．０２５ｍｍのＰＥからなる微孔性セパレータ（旭化成社製 ハイポア）を２２０ｍｍに切断し、図３（ａ）に示すごとく２つ割の直径４ｍｍの巻芯２５に挟んで１周巻いた。次いで、図３（ｂ）・（ｃ）に示すごとく、負極４のリチウム金属箔の一重長さが１０ｍｍの方を巻芯２５側にして、セパレータ５と同時に１周巻き込んだのち、正極シート２０・２１を固定した方を巻芯２５側に載置して捲回した。捲回終了後は、セパレータ５が最外周を覆う形となり、セパレータ５の巻き終わり部を固定テープで固定した。捲回末端部Ｅに係るセパレータ５を折り曲げ、該セパレータ５で正極シート２０・２１が被覆されるようにした。以上より、図１に示すような電極捲回体６を得た。
【００４７】
ニッケルメッキした鉄缶からなる外装缶２の底に、厚さ０．２ｍｍのＰＰ製絶縁板を挿入し、その上に電極捲回体６を正負極のリード体１５・１６が上側に向く姿勢で挿入した。負極リード体１６は、外装缶２の上部内面に抵抗溶接した。正極リード体１５は、絶縁板１１を挿入したのち、端子体１０の下面に抵抗溶接した。この時点で絶縁抵抗を測定し、短絡がないことを確認した。
【００４８】
電解液は、０．５Ｍ ＬｉＣｌＯ４ ／（ＰＣ＋ＤＭＥ＝１：２）を、外装缶２内に３．３±０．１ｍｌ注入した。注入は３度に分け、最終工程で減圧にして全量を注入した。電解液の注入後、蓋体８を嵌合・レーザ溶接により封口した。以上により、実施例１に係る非水電解液電池を得た。
【００４９】
（後処理：予備放電、エージング）
封口した電池は、１Ωの抵抗で３０秒間予備放電し、４５℃で２４時間保管した後、１Ａの低電流で３分間２次予備放電を行った。予備放電後の電池を、室温で７日間エージングし、開路電圧を測定した。
【００５０】
《実施例２》
内周側の正極シートの長さ寸法を５１．５ｍｍ、外周側の正極シートの長さ寸法を６１．５ｍｍとした以外は、実施例１と同様にして電極捲回体を得て、これを外装缶内に装填して実施例２に係る非水電解液電池を得た。電極捲回体の形態は、図１に示すごとくであった。
【００５１】
《実施例３》
内周側の正極シートの長さ寸法を４９．５ｍｍ、外周側の正極シートの長さ寸法を６３．５ｍｍとした以外は、実施例１と同様にして電極捲回体を得て、これを外装缶内に装填して実施例３に係る非水電解液電池を得た。電極捲回体の形態は、図４のごとくであった。
【００５２】
《実施例４》
内周側の正極シートの長さ寸法を５０．５ｍｍ、外周側の正極シートの長さ寸法を６２．５ｍｍとし、両正極シートの捲回末端部にプレス加工を施して、厚み寸法が０．５ｍｍの薄肉部を形成した。すなわち得られた電極捲回体は、図５に示すごとくであった。それ以外は、実施例１と同様にして実施例４に係る非水電解液電池を得た。
【００５３】
《比較例１》
内周側の正極シートの長さ寸法を５２ｍｍ、外周側の正極シートの長さ寸法を６１ｍｍとした以外は、実施例１と同様にして電極捲回体を得て、これを外装缶内に装填して比較例１に係る非水電解液電池を得た。
【００５４】
《比較例２》
内周側の正極シートの長さ寸法を４９ｍｍ、外周側の正極シートの長さ寸法を６４ｍｍとした以外は、実施例１と同様にして電極捲回体を得て、これを外装缶内に装填して比較例２に係る非水電解液電池を得た。
【００５５】
《比較例３》
内周側の正極シートの長さ寸法を５０．５ｍｍ、外周側の正極シートの長さ寸法を６２．５ｍｍとした以外は、実施例１と同様にして電極捲回体を得て、これを外装缶内に装填して比較例３に係る非水電解液電池を得た。
【００５６】
上記実施例１〜４および比較例１〜３の非水電解液電池の捲回末端部のずれを測定した。外周側が短く、内周側が長い場合を正、短い場合を負と定義した。ここでは、各実施例および比較例に係る電池を１００個ずつ作製して、その捲回末端部のずれ幅を測定した。また、２３℃、１０ｍＡと３００ｍＡで２．０Ｖまで放電させ放電容量を比較した。１０ｍＡでの放電を電池の軽負荷容量、３００ｍＡを中負荷容量と定義した。
【００５７】
組立時の短絡の発生個数を比較した。これは、電池に電極捲回体を挿入した後の絶縁抵抗値（１Ω以下）と、予備放電後のエージング中の開路電圧変化（平均値より５０ｍＶ以上低下）により調べた。
【００５８】
上記実施例１〜４および比較例１〜３の電池についての捲回末端部のずれ幅、短絡発生率、および放電特性を表１に示す。
【００５９】
【表１】

Figure 2004327291
【００６０】
表１に示す結果から明らかなように、比較例３に係る電池は短絡の発生率が高く、その点に不具合があることがわかる。これは図７に示すごとく、両正極シート２０・２１の捲回末端部Ｅが揃っているため、外装缶２内への電極捲回体６の装填時に、捲回末端部Ｅに係るセパレータ５が、外方向に大きく張り出した正極シート２１のエッジ部２１ａで損傷されたことに拠る。
【００６１】
比較例１および比較例２より、捲回末端部Ｅに係る内外周の正極シート２０・２１の位置ずれ幅Ｗが、正極シート２０・２１の厚み寸法Ｌの２倍以上と大きいと、短絡を引き起こすおそれがあることがわかる。これは集電体２２が正極シート２０・２１の端から突出することに拠る。また、比較例１および比較例２に係る非水電解液電池は、実施例に係る非水電解液電池と比較して、軽負荷での特性は遜色ないが、中負荷での特性は明らかな低下が認められる。これは集電体２２の片面に正極シート２０・２１がない部分では、正極シート２０・２１と集電体２２との密着性が多少劣るため、集電効率が低下したことに拠る。
【００６２】
これに対して、実施例１、２、３の非水電解液電池のごとく、捲回末端部に係る内外周の正極シート２０・２１を、ずれ幅Ｗが正極シートの厚み寸法Ｌの１／２以上、２倍以下の範囲で位置ずれさせた形態では、短絡は一切生じなかった。これは、正極シート２０・２１を位置ずれさせることで、外周側の正極シート２１の捲回末端部Ｅの外方向への張り出し幅を小さく抑えて、セパレータ５の損傷を良好に解消できたことに拠る。また、実施例２、３より、ずれ幅Ｗが正極シート２０・２１の厚み寸法Ｌの１／２以上、２倍以下の範囲であれば、中負荷の特性も問題ないことがわかる。
【００６３】
実施例４より、内外周の正極シート２０・２１の捲回末端部Ｅが、揃っている場合でも、図５に示すごとく薄肉部２７を設けておけば、短絡は生じず、電池特性も良好であることがわかる。
【図面の簡単な説明】
【図１】本発明の第１実施形態に係る非水電解液電池の横断平面図である。
【図２】本発明の非水電解液電池の縦断正面図である。
【図３】電極捲回体の作製方法を説明するための図である。
【図４】本発明の第２実施形態に係る非水電解液電池の横断平面図である。
【図５】本発明の第３実施形態に係る非水電解液電池の横断平面図である。
【図６】本発明の第４実施形態に係る非水電解液電池の横断平面図である。
【図７】従来形態に係る非水電解液電池の横断平面図である。
【符号の説明】
１ 非水電解液電池
２ 外装缶
３ 正極
４ 負極
５ セパレータ
６ 電極捲回体
２０ 内周側に位置する正極シート
２１ 外周側に位置する正極シート
２２ 集電体
Ｓ 正極の捲回始端部
Ｅ 正極の捲回末端部
Ｗ ずれ幅
Ｌ 正極シートの厚み寸法[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a non-aqueous electrolyte battery, and more particularly, to a high-capacity, safe and highly reliable cylindrical non-aqueous electrolyte battery suitable for use under a medium load.
[0002]
[Prior art]
As the cylindrical non-aqueous battery, a bobbin-type battery having a high capacity but a light load, such as a memory bag, and a wound type battery capable of handling a heavy load such as a camera power supply are widely known. The former bobbin type battery has been commercialized as CR or ER battery, but it has a simple structure, can be manufactured at low cost, and can be filled with many active materials, but has a small electrode area. Since the load characteristics are inferior, there is a disadvantage that the capacity is reduced when attempting to discharge with a large current.
[0003]
The latter wound type battery having heavy load characteristics has been commercialized in a CR or BR configuration. In this type of battery, a spiral electrode body formed by winding a thin and long electrode is used as a battery element, so that a large electrode area can be secured and a large capacity can be obtained even when discharging with a large current. However, since a large number of separators and current collectors that do not directly contribute to the improvement of the battery characteristics are provided in the electrode body, the amount of the active material to be filled must be reduced, and the battery capacity is inevitably reduced. In addition, while large currents can be extracted, when abnormalities such as short-circuits occur, they generate a lot of heat and there is a risk of ignition, and various safety measures are required, and the battery structure is complicated and the production cost increases. is there.
[0004]
Due to recent diversification of application equipment, not only light-load applications such as memory back and heavy-load applications such as cameras, but also medium-load applications such as data transmission and reception are increasing. There has been a demand for the development of batteries that can be used. Therefore, Patent Literatures 1 and 2 propose a battery in which an electrode wound body in which a thick electrode is wound several times is used as a battery element. According to the battery in which such an electrode wound body is used as a battery element, the use of a thicker electrode reduces the amount of separators and current collectors used compared to a conventional battery with heavy load characteristics, and reduces the filling of the active material. This is advantageous in that a high-capacity battery can be obtained. In addition, by preventing an extremely large current from flowing, a battery excellent in safety and reliability and excellent in medium load characteristics can be obtained.
[0005]
[Patent Document 1]
JP-A-6-267584 (paragraph number 0017, FIGS. 1 and 3)
[Patent Document 2]
JP-A-9-190836 (paragraph number 0019, FIG. 1)
[0006]
[Problems to be solved by the invention]
However, the positive electrodes of the batteries described in Patent Literature 1 and Patent Literature 2 have poor flexibility and flexibility because the active material mixture is filled in the voids of the current collector made of a nickel foam. . For this reason, when the thickness dimension is large, there is a disadvantage that the electrode is easily cracked or cut at the time of winding, and the active material is dropped, and a short circuit or poor conductivity is easily caused.
[0007]
Therefore, as shown in FIG. 7, the present inventors have formed a positive electrode 3 into two positive sheets 20 and 21 formed by forming a positive electrode active material into a sheet shape, and a collection interposed between the positive sheets 20 and 21. The electrode wound body 6 was manufactured by winding these. Here, at the time of forming the electrode wound body 6, the positive electrode sheets 20 and 21 and the current collector 22 were wound with only the winding start end S fixed. According to this, by dividing the positive electrode 3 into two positive electrode sheets 20 and 21, the flexibility of the positive electrode 3 is improved as compared with the conventional configuration in which the active material is filled in the voids of the current collector made of foamed metal. Since the properties and flexibility can be improved, it is possible to effectively eliminate the occurrence of cracking or cutting of the positive electrode 3 at the time of winding, falling off of the active material, and the like.
[0008]
However, as shown in FIG. 7, if the two positive electrode sheets 20 and 21 in the wound end portion E are aligned, the wound end portion E of the outer circumferential side positive electrode sheet 21 greatly protrudes outward, so that When inserting the electrode winding body 6 into the cylindrical outer can 2, the end face edge portion 21 a of the positive electrode sheet 21 on the outer peripheral side related to the winding end portion E damages the separator 5 and easily causes a short circuit.
[0009]
An object of the present invention is to provide a nonaqueous electrolyte battery in which a battery element is an electrode wound body obtained by winding a sheet-shaped positive electrode having a large thickness and a short thickness together with a negative electrode and a separator. An object of the present invention is to obtain a nonaqueous electrolyte battery excellent in safety and reliability by suppressing occurrence of a short circuit caused by damage to a separator at an end face edge.
[0010]
[Means for Solving the Problems]
As shown in FIG. 2, the present invention relates to an electrode wound body 6 formed by winding a sheet-shaped positive electrode 3 and a negative electrode 4 through a separator 5 in a bottomed cylindrical outer can 2 having an upper opening. And a cylindrical non-aqueous electrolyte battery containing a non-aqueous electrolyte. As shown in FIGS. 1 and 4, the electrode winding body 6 has a winding number defined by the winding start end S and the winding end E of the positive electrode 3 of 1.6 turns or more and 2.5 turns or less. The positive and negative electrodes 3 and 4 and the separator 5 are wound so as to form a substantially cylindrical shape as a whole. The positive electrode 3 includes two positive electrode sheets 20 and 21 having the same thickness and a current collector 22 interposed between the positive electrode sheets 20 and 21. The positive electrode sheets 20 and 21 and the current collector 22 are wound with only the winding start end S fixed. Each of the positive electrode sheets 20 and 21 is formed by molding a positive electrode active material into a sheet having a thickness of 0.5 mm or more and 2 mm or less.
[0011]
In addition, as shown in FIGS. 1 and 4, the two positive sheets 20 and 21 constituting the positive electrode 3 are disposed at the outermost periphery of the electrode winding body 6 at the winding end portions, as shown in FIGS. E is in an irregular displacement state, and the displacement width W of the wound end portions E of the two positive electrode sheets 20 and 21 is set to be equal to or more than １ ／ and twice or less the thickness L of the positive electrode sheets 20 and 21. It is characterized by having been done.
[0012]
As shown in FIG. 1, at the outermost periphery of the electrode wound body 6, the wound end portion E of the positive electrode sheet 20 located on the inner peripheral side is longer than the wound terminal end E of the positive electrode sheet 21 located on the outer peripheral side. More preferably, it is in the extended position shift state.
[0013]
Further, as shown in FIG. 2, the present invention provides an electrode wound body formed by winding a sheet-like positive electrode 3 and a negative electrode 4 through a separator 5 in a bottomed cylindrical outer can 2 having an upper opening. 6 and a non-aqueous electrolyte battery containing a non-aqueous electrolyte solution. As shown in FIG. 5, the electrode winding body 6 is configured such that the number of turns defined by the winding start end S and the winding end E of the positive electrode 3 is 1.6 turns or more and 2.5 turns or less. It is formed by winding the positive and negative electrodes 3 and 4 and the separator 5 and is formed into a substantially cylindrical shape as a whole. The positive electrode 3 includes two positive electrode sheets 20 and 21 having the same thickness and a current collector 22 interposed between the positive electrode sheets 20 and 21. The positive electrode sheets 20 and 21 and the current collector 22 are wound with only the winding start end S fixed. Each of the positive electrode sheets 20 and 21 is formed by molding a positive electrode active material into a sheet having a thickness of 0.5 mm or more and 2 mm or less.
[0014]
In addition, as shown in FIG. 5, the present invention according to claim 3 provides a thin wall having a thickness smaller than that of the other at the outermost periphery of the electrode winding body 6 at the wound end portion E of the positive electrode sheet 21 located on the outer peripheral side. It is characterized in that a part 27 is formed.
[0015]
Further, as shown in FIG. 2, the present invention provides an electrode wound body formed by winding a sheet-like positive electrode 3 and a negative electrode 4 through a separator 5 in a bottomed cylindrical outer can 2 having an upper opening. 6 and a non-aqueous electrolyte battery containing a non-aqueous electrolyte solution. As shown in FIG. 6, the electrode winding body 6 is configured such that the number of windings defined by the winding start end S and the winding end E of the positive electrode 3 is 1.6 turns or more and 2.5 turns or less. It is formed by winding the positive and negative electrodes 3 and 4 and the separator 5 and is formed into a substantially cylindrical shape as a whole. The positive electrode 3 includes two positive electrode sheets 20 and 21 having the same thickness and a current collector 22 interposed between the positive electrode sheets 20 and 21. The positive electrode sheets 20 and 21 and the current collector 22 are wound with only the winding start end S fixed. Each of the positive electrode sheets 20 and 21 is formed by molding a positive electrode active material into a sheet having a thickness of 0.5 mm or more and 2 mm or less.
[0016]
In addition, as shown in FIG. 6, the outer edge of the wound end portion E of the positive electrode sheet 21 located on the outer peripheral side at the outermost periphery of the electrode wound body 6 is chamfered as shown in FIG. 6. It is characterized by having.
[0017]
Effects of the Invention
In a battery that uses a spiral electrode body formed by winding a thin and long sheet-like positive / negative electrode through a separator, as a battery element, the thickness of the positive / negative electrode is extremely small. It is easy to do. In other words, since the outwardly extending width of the wound terminal portions of the positive and negative electrodes is so small as to be negligible, when loading the electrode body into the cylindrical outer can, it is necessary to force the wound terminal portions. Such a situation does not occur, and there is no problem that the separator at the winding end portion is damaged by the positive and negative electrodes to cause a short circuit.
[0018]
On the other hand, as in the nonaqueous electrolyte battery according to the present invention, when a battery element is an electrode wound body formed by winding a positive electrode having a large thickness and a small length, an electrode winding is required. It is difficult to shape the body into a columnar shape, and the width of the positive and negative electrodes that protrude outward from the winding ends becomes a problem when the positive and negative electrodes are loaded into the outer can. That is, as shown in FIG. 5, if the wound end portions E of the positive electrode sheets 20 and 21 are aligned and the wound end portion E of the positive electrode 3 is inadvertently greatly extended outward, When the electrode body 6 is loaded into the cylindrical outer can 2, the wound end portion E must be forcibly inserted. As a result, the positive electrode sheet in which the separator 5 related to the wound end portion E is located on the outer peripheral side is used. 21 may be damaged at the edge portion 21a and cause a short circuit.
[0019]
Therefore, in the nonaqueous electrolyte battery of the present invention, as shown in FIGS. 1 and 4, the two positive electrode sheets 20 and 21 constituting the positive electrode 3 are displaced in such a manner that the winding end portions E thereof are not aligned. It is like that. By providing the steps on the positive electrode sheets 20 and 21 in this manner, the outwardly projecting width of the wound end portion E of the positive electrode sheet 21 on the outer peripheral side can be suppressed to be small, and as shown in FIG. Damage to the separator 5 caused by the edge 21a of the wound end portion E of the positive electrode sheet 21 on the outer peripheral side protruding largely outward, which is inevitable when the sheets 20 and 21 are aligned without being displaced. Can be eliminated, and the occurrence of a short circuit can be effectively prevented. In particular, as shown in FIG. 1, if the wound end portion E of the positive electrode sheet 20 located on the inner peripheral side extends longer than the wound end portion E of the positive electrode sheet 21 located on the outer peripheral side, Since the internal space of the can 2 can be effectively used without waste, the dead space can be minimized and the discharge capacity can be improved.
[0020]
In addition, the deviation width W of the winding end portions E of the two positive electrode sheets 20 and 21 is 以上 to 2 times the thickness L of the positive electrode sheets, more preferably 0.7 to 1.5 times. Set to. If the shift width W is less than half the thickness L of the positive electrode sheet, the effect of shifting the positive electrode sheets 20 and 21 cannot be obtained, and the separator 5 may be damaged when the electrode winding body 6 is loaded into the outer can 2. May cause a short circuit. If the shift width W exceeds twice the thickness L of the positive electrode sheets 20 and 21, the current collector 22 may protrude from the winding end portion E of the positive electrode sheets 20 and 21 and cause a short circuit. In addition, since the adhesiveness of a portion where the positive electrode sheets 20 and 21 are not provided on one surface of the current collector 22 is poor, battery characteristics (discharge capacity) under a medium load are reduced.
[0021]
As shown in FIG. 5, if a thinner portion 27 having a smaller thickness than the others is formed at the outermost periphery of the electrode wound body 6 at the wound end portion E of the positive electrode sheet 21 located on the outer peripheral side, Since the contact between the positive electrode sheet 21 on the outer peripheral side relating to the end portion E and the separator 5 can be suppressed, the occurrence of a short circuit due to damage to the separator 5 can be suppressed.
[0022]
As shown in FIG. 6, at the outermost periphery of the electrode wound body 6, the outer edge of the wound end portion E of the positive electrode sheet 21 located on the outer peripheral side is chamfered and formed at the wound end portion E of the positive electrode sheet 21. If the outer peripheral side edge is shaved, damage to the separator 5 can be reliably suppressed, and short-circuiting can be prevented well.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
First Embodiment FIGS. 1 to 3 show a nonaqueous electrolyte battery according to a first embodiment of the present invention. In FIG. 2, a nonaqueous electrolyte battery 1 includes an outer can 2 having a bottomed cylindrical shape having an upper opening, a positive electrode 3 and a negative electrode 4 loaded in the outer can 2, and an upper opening of the outer can 2. And a sealing structure for sealing. The positive electrode 3 and the negative electrode 4 are housed in an outer can 2 together with an electrolytic solution as an electrode wound body 6 wound with a separator 5 interposed therebetween. The outer can 2 is made of iron or stainless steel.
[0024]
The sealing structure includes a cover plate 8 fixed to the inner peripheral edge of the upper opening of the outer can 2, and a terminal body attached to an opening formed in the center of the cover plate 8 via a rubber insulating packing 9. 10 and an insulating plate 11 arranged below the cover plate 8. The insulating plate 11 is formed in the shape of an upwardly opening round plate with an annular side wall 13 erected on the periphery of a disk-shaped base portion 12, and a gas passage 14 is opened in the center of the base portion 12. I have. The cover plate 8 is fixed to the inner peripheral edge of the upper opening of the outer can 2 by a crimp seal via laser welding or packing while being received by the upper end of the side wall 13. A thin portion may be provided on the lid plate 8 or the can bottom 2a of the outer can 2, and a vent may be provided as a countermeasure when the internal pressure is rapidly increased. The positive electrode 3 and the lower surface of the terminal body 10 are connected by a positive electrode lead body 15, and the negative electrode terminal 4 and the inner surface of the outer can 2 are connected by a negative electrode lead body 16.
[0025]
As shown in FIG. 1, the electrode winding body 6 has a winding number defined by the winding start end S and the winding end E of the positive electrode 3 of 1.6 turns or more and 2.5 turns or less. The positive and negative electrodes 3 and 4 and the separator 5 are wound around the substrate, and are formed in a substantially columnar shape as a whole. FIG. 1 shows an embodiment in which the number of turns is about 1.6. The positive electrode 3 includes two positive electrode sheets 20 and 21 having the same thickness and a current collector 22 interposed between the positive electrode sheets 20 and 21. The positive electrode sheets 20 and 21 and the current collector 22 are wound with only the winding start end S fixed (see FIG. 3C).
[0026]
The positive electrode sheets 20 and 21 are formed by forming a positive electrode active material into a sheet having a thickness L of 0.5 mm or more and 2 mm or less. Examples of the positive electrode active material include manganese dioxide, carbon fluoride, lithium cobalt composite oxide, and spinel lithium manganese composite oxide.
[0027]
As the conduction aid of the positive electrode 3, one kind selected from graphite, carbon black, acetylene black, and Ketjen black, or a composite of two or more kinds can be used, but Ketjen black can be used as a main component. preferable. As the binder of the positive electrode 3, Teflon dispersion, powdered Teflon (registered trademark), a rubber-based binder, or the like can be used, but Teflon dispersion is preferably used.
[0028]
As the positive electrode lead body 15, a plain woven metal mesh made of stainless steel 316, 430, 444, or the like, an expanded metal, a lath net, a punching metal, a foil, or the like can be used.
[0029]
The negative electrode 4 is formed in a thin plate shape (foil shape), and examples of the material include lithium metal, alloys such as lithium and aluminum, and carbon materials such as graphite. As shown in FIGS. 1 and 3 (b), the negative electrode 4 is formed by laminating two short and long negative electrodes 4a and 4b, and these are wound together with the positive electrode 3 and the separator 5 to form an electrode. A wound body 6 is produced. As the negative electrode lead member 16, a nickel ribbon, a stainless steel plain woven wire mesh, an expanded metal, a lath mesh, a punching metal, or the like can be used.
[0030]
As an electrolyte, LiPF is used as a solute. 6 , LiClO 4 , LiCF 3 SO 3 , (CF 3 SO 2 ) 2 As a solvent in which NLi or the like is dissolved in an amount of 0.3 to 1.5 M / l, an electrolytic solution obtained by mixing a chain ether such as DME or a chain carbonate such as dimethyl carbonate with a cyclic carbonate such as PC or EC is used.
[0031]
As the separator 5, a nonwoven fabric such as PP, PE, PET, PBT, or PPS, a microporous film, or the like can be used.
[0032]
The electrode wound body can be manufactured by a procedure as shown in FIG. First, as shown in FIG. 3 (a), the separator 5 is wound around the core 25 in two turns. Next, as shown in FIG. 3B, the negative electrode 4 is inserted from one layer portion of only the short length 4a toward the core 25 and wound around the separator 5 one round (see FIG. 3C). Subsequently, as shown in FIG. 3C, the positive electrode 3 is placed on the negative electrode 4 via the separator 5 and wound around the core 25. Here, the positive electrode 3 is wound from the side of the winding start end S to which the two positive electrode sheets 20 and 21 and the current collector 22 are fixed, and is placed on the long negative electrode 4 b via the separator 5. It is wound in the state where it was done. After the completion of the winding, the separator 5 covers the outermost periphery, and the wound end portion E of the separator 5 is fixed with a fixing tape. As described above, the electrode wound body 6 having the form shown in FIG. 1 can be obtained.
[0033]
By adjusting the length dimensions of the two positive electrode sheets 20 and 21 located on the inner and outer circumferences, the form of the positive electrode 3 related to the wound end portion E can be appropriately changed. Here, as shown in FIG. 1, the positive electrode sheet 20 on the inner peripheral side related to the winding end portion E is extended longer than the positive electrode sheet 21 on the outer peripheral side. The length dimensions of both positive electrode sheets 20 and 21 are adjusted so as to be in a state. As a result, it is possible to reduce the outward width of the wound end portion E of the outer peripheral side positive electrode sheet 21, so that the two positive electrode sheets 20 and 21 are aligned without being displaced as shown in FIG. 7. In this case, it is impossible to effectively prevent the separator 5 from being damaged due to the edge portion of the wound end portion E of the positive electrode sheet 21 on the outer peripheral side protruding largely outward, and to effectively prevent the occurrence of a short circuit. it can. That is, by suppressing the outwardly extending width of the wound end portion E of the outer peripheral side positive electrode sheet 21 to be small, the winding end portion of the positive electrode sheet 21 can be loaded into the outer can 2 when the electrode wound body 6 is loaded. The edge portion 21a of E and the inner peripheral surface of the outer can 2 are strongly rubbed, so that it is possible to prevent the intervening separator 5 from being damaged.
[0034]
In addition, the deviation width W of the wound end portions E of the two positive electrode sheets 20 and 21 is set to 以上 or more and twice or less the thickness L of the positive electrode sheets 20 and 21, more preferably 0.7 or more, Set to 5 times or less. If the shift width W is less than の of the thickness of the positive electrode sheets 20 and 21, the effect of shifting the positive electrode sheets 20 and 21 cannot be obtained, and the separator 5 is damaged, and a short circuit is likely to occur. If the shift width W exceeds twice the thickness L of the positive electrode sheets 20 and 21, the current collector 22 may protrude from the winding end portion E of the positive electrode sheets 20 and 21 and cause a short circuit. In addition, since the adhesiveness of a portion where the positive electrode sheets 20 and 21 are not provided on one surface of the current collector 22 is poor, battery characteristics (discharge capacity) under a medium load are reduced.
[0035]
Second Embodiment FIG. 4 shows a nonaqueous electrolyte battery according to a second embodiment of the present invention. The nonaqueous electrolyte battery in this case differs from the first embodiment in that the inner peripheral side positive electrode sheet 20 related to the winding end portion E is shorter than the outer peripheral side positive electrode sheet 21. . This also makes it possible to suppress the outward extension of the wound end portion E of the positive electrode sheet 21 on the outer peripheral side, so that damage to the separator 5 at the time of loading into the outer can 2 is suppressed, and occurrence of a short circuit is prevented. Can be prevented well.
[0036]
Third Embodiment FIG. 5 shows a nonaqueous electrolyte battery according to a third embodiment of the present invention. The non-aqueous electrolyte battery 1 in this case differs from the first embodiment in that the wound end portions E of the positive electrode sheets 20 and 21 are thinner portions 27 having a smaller thickness than the other. The thin portion 27 can be formed, for example, by subjecting the wound end portions E of the positive electrode sheets 20 and 21 to press working. By providing the thin portion 27 at the wound end portion E of the positive electrode sheets 20 and 21 in this manner, contact between the positive electrode sheet 21 on the outer peripheral side related to the wound end portion E and the separator 5 can be suppressed, and 5 can be suppressed from occurring due to damage. Although FIG. 5 shows an example in which the thin portion 27 is provided at the wound end portion E of both the positive electrode sheets 20 and 21, the thin portion 27 may be provided only on the outer peripheral side positive electrode sheet 21. .
[0037]
Fourth Embodiment FIG. 6 shows a nonaqueous electrolyte battery according to a fourth embodiment of the present invention. In the non-aqueous electrolyte battery 1 in this case, the first embodiment is characterized in that the outer edges of the wound end portions E of both the positive electrode sheets 20 and 21 are shaved and chamfered in an R shape. Is different from In FIG. 6, reference numeral 28 indicates a chamfered portion. This can also suppress the damage to the separator 5 and effectively prevent the occurrence of a short circuit. In addition, only the outer peripheral side positive electrode sheet 21 may be chamfered.
[0038]
【Example】
Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In this embodiment, a CR battery will be described as an example.
[0039]
<< Example 1 >>
<Positive electrode manufacturing method>
(Blending) After mixing for 5 minutes in a dry manner using a planetary mixer at a ratio of 3% of Ketjen Black and 92% of manganese dioxide (manufactured by Tosoh Corporation), water was added at a weight ratio of 20% to 5% by weight. Mix for minutes. Teflon dispersion (D-1 manufactured by Daikin Industries, Ltd.) was added in a state where 5% as a solid content was diluted in the remaining water, and mixed for 5 minutes. The water content in the compounding agent was adjusted to 25 to 30 with respect to 100 solids.
[0040]
(Sheet formation) The mixed compounding agent was rolled using two rolls having a diameter of 250 mm, the roll temperature was adjusted to 130 ± 5 ° C., the press pressure was 7 tons / cm, the roll interval was 0.4 mm, the rotation speed was 10 rpm, and the rolls were rolled. , Into sheets. The compounding agent (preliminary sheet) passed through the roll was dried at 105 ° C. ± 5 ° C. until the residual moisture became 2% or less. Next, the dried preliminary sheet was pulverized using a pulverizer. Here, the pressed spare sheet was pulverized with a coffee mill until it reached at least twice the original apparent volume. Most of the pulverized particle diameter was 1 mm or less, and the Teflon (registered trademark) fiber added as a binder was also cut to a length of 1 mm or less.
[0041]
The pulverized material was again rolled into a sheet. The interval between the rolls was adjusted to 0.6 ± 0.05 mm, the roll temperature was set to 120 ± 10 ° C., the press pressure was 7 tons / cm, and the rotation speed was 10 rpm, to obtain a positive electrode sheet. The positive electrode sheet has a thickness of 1.0 mm and a density of 2.6 g / cm. 3 Met.
[0042]
As described above, two positive electrode sheets 20 and 21 for the inner circumference and the outer circumference (see FIGS. 1 and 3C) were prepared. The inner peripheral positive electrode sheet 20 was cut into a width of 37 mm and a length of 51 mm. The outer peripheral positive electrode sheet 21 was cut into a width of 37 mm and a length of 62 mm.
[0043]
(Current collector) A lath net made of stainless steel 316 (manufactured by Nikken Las) was used as the current collector 22. This lath net was cut into a width of 35 mm and a length of 56 mm, and a positive electrode lead 15 made of a stainless steel ribbon having a thickness of 0.3 mm and a width of 3 mm was attached to a central portion in the length direction by resistance welding. After a carbon paste (manufactured by Nippon Graphite Co., Ltd.) was applied to the current collector 22 to such an extent that the mesh was not broken, it was dried at a heating temperature of 105 ° C. ± 5 ° C. for 2 hours or more. Here, 4 mg / cm 2 The carbon paste was applied so that
[0044]
Next, as shown in FIG. 3C, the two positive sheets 20 and 21 are integrated with the current collector 22 interposed therebetween and only one end in the length direction is fixed. did. Specifically, the two inner and outer positive electrode sheets 20 and 21 are set so that one end in the length direction is aligned and the end of the current collector 22 does not protrude from the positive electrode sheets 20 and 21. In this state, 3 to 10 mm from the end in the length direction was pressed by a press to integrate the three members. Subsequently, the positive electrode sheets 20 and 21 and the current collector 22 were dried with hot air at 250 ° C. ± 10 ° C. for 6 hours to obtain a positive electrode 3. Here, the integration of the positive electrode sheets 20 and 21 and the current collector 22 is a problem in operation, and the independent positive electrode sheets 20 and 21 and the current collector 22 are integrated at the time of winding. However, there is no problem in characteristics.
[0045]
<Negative electrode manufacturing method>
The negative electrode 4 was obtained by cutting a lithium foil having a width of 37 mm and a thickness of 0.3 mm into 36 mm and 96 mm, and excluding 10 mm from one end of the short side foil 4 a, 36 mm was overlapped with the long side foil 4 b and pressed. The negative electrode lead body 16 was formed by embossing one end of a nickel ribbon having a thickness of 0.1 mm and a width of 3 mm, and was fixed by being pressed between two foils.
[0046]
<Assembly method>
A microporous separator made of PE having a width of 44 mm and a thickness of 0.025 mm (Hipore manufactured by Asahi Kasei Corporation) was cut into 220 mm, and as shown in FIG. Wrapped around. Next, as shown in FIGS. 3B and 3C, the lithium metal foil of the negative electrode 4 is wound around the core 25 side with the single length of 10 mm, and is wound around the separator 5 once, and then the positive electrode sheet 20 is wound. -The one with 21 fixed was placed on the core 25 side and wound. After the completion of the winding, the separator 5 covered the outermost periphery, and the winding end portion of the separator 5 was fixed with a fixing tape. The separator 5 related to the winding end portion E was bent so that the positive electrode sheets 20 and 21 were covered with the separator 5. From the above, an electrode wound body 6 as shown in FIG. 1 was obtained.
[0047]
A 0.2-mm-thick PP insulating plate is inserted into the bottom of the outer can 2 made of a nickel-plated iron can, and the electrode winding body 6 is placed thereon with the positive and negative electrode leads 15 and 16 facing upward. Inserted in. The negative electrode lead body 16 was resistance-welded to the upper inner surface of the outer can 2. The positive electrode lead body 15 was resistance-welded to the lower surface of the terminal body 10 after the insulating plate 11 was inserted. At this time, the insulation resistance was measured, and it was confirmed that there was no short circuit.
[0048]
The electrolyte is 0.5M LiClO 4 / (PC + DME = 1: 2) was injected into the outer can 2 by 3.3 ± 0.1 ml. The injection was divided into three times, and the whole amount was injected under reduced pressure in the final step. After the injection of the electrolyte, the lid 8 was fitted and sealed by laser welding. Thus, a nonaqueous electrolyte battery according to Example 1 was obtained.
[0049]
(Post-treatment: pre-discharge, aging)
The sealed battery was pre-discharged at a resistance of 1Ω for 30 seconds, stored at 45 ° C. for 24 hours, and then subjected to a secondary pre-discharge at a low current of 1 A for 3 minutes. The battery after the preliminary discharge was aged at room temperature for 7 days, and the open circuit voltage was measured.
[0050]
<< Example 2 >>
An electrode wound body was obtained in the same manner as in Example 1 except that the length dimension of the inner peripheral side positive electrode sheet was 51.5 mm and the length dimension of the outer peripheral side positive electrode sheet was 61.5 mm. The nonaqueous electrolyte battery according to Example 2 was obtained by charging the battery in the outer can. The form of the electrode wound body was as shown in FIG.
[0051]
<< Example 3 >>
An electrode wound body was obtained in the same manner as in Example 1, except that the length of the inner positive electrode sheet was 49.5 mm and the length of the outer positive electrode sheet was 63.5 mm. The nonaqueous electrolyte battery according to Example 3 was obtained by charging the battery in the outer can. The form of the electrode wound body was as shown in FIG.
[0052]
<< Example 4 >>
The inner positive electrode sheet has a length of 50.5 mm and the outer positive electrode sheet has a length of 62.5 mm. A thin portion of 5 mm was formed. That is, the obtained electrode wound body was as shown in FIG. Otherwise, in the same manner as in Example 1, a nonaqueous electrolyte battery according to Example 4 was obtained.
[0053]
<< Comparative Example 1 >>
An electrode wound body was obtained in the same manner as in Example 1, except that the length of the inner peripheral side positive electrode sheet was set to 52 mm, and the length of the outer peripheral side positive electrode sheet was set to 61 mm. The battery was loaded to obtain a nonaqueous electrolyte battery according to Comparative Example 1.
[0054]
<< Comparative Example 2 >>
An electrode wound body was obtained in the same manner as in Example 1, except that the length of the positive electrode sheet on the inner peripheral side was set to 49 mm, and the length of the positive electrode sheet on the outer peripheral side was set to 64 mm. By loading, a nonaqueous electrolyte battery according to Comparative Example 2 was obtained.
[0055]
<< Comparative Example 3 >>
An electrode wound body was obtained in the same manner as in Example 1, except that the length of the inner positive electrode sheet was 50.5 mm and the length of the outer positive electrode sheet was 62.5 mm. The nonaqueous electrolyte battery according to Comparative Example 3 was obtained by charging the battery in the outer can.
[0056]
The displacement of the wound end portions of the nonaqueous electrolyte batteries of Examples 1 to 4 and Comparative Examples 1 to 3 was measured. The case where the outer circumference side is short and the inner circumference side is long is defined as positive, and the case where it is short is defined as negative. Here, 100 batteries according to each of the examples and the comparative examples were manufactured, and the deviation width of the wound end portion was measured. Further, the battery was discharged to 2.0 V at 23 ° C., 10 mA and 300 mA, and the discharge capacities were compared. The discharge at 10 mA was defined as the light load capacity of the battery, and 300 mA was defined as the medium load capacity.
[0057]
The number of occurrences of short circuits during assembly was compared. This was examined based on the insulation resistance value (1 Ω or less) after inserting the electrode winding body into the battery and the change in open-circuit voltage during aging after preliminary discharge (50 mV or more lower than the average value).
[0058]
Table 1 shows the deviation width of the wound end portion, the short-circuit occurrence rate, and the discharge characteristics of the batteries of Examples 1 to 4 and Comparative Examples 1 to 3.
[0059]
[Table 1]
Figure 2004327291
[0060]
As is clear from the results shown in Table 1, the battery according to Comparative Example 3 has a high short-circuit occurrence rate, which indicates that there is a problem in that point. As shown in FIG. 7, since the wound end portions E of both the positive electrode sheets 20 and 21 are aligned, when the electrode wound body 6 is loaded into the outer can 2, the separator 5 related to the wound end portion E is formed. Is damaged at the edge portion 21a of the positive electrode sheet 21 which largely protrudes outward.
[0061]
From Comparative Example 1 and Comparative Example 2, when the positional deviation width W of the inner and outer peripheral positive electrode sheets 20 and 21 related to the wound end portion E is as large as twice or more the thickness L of the positive electrode sheets 20 and 21, a short circuit occurs. It is understood that there is a possibility of causing. This is because the current collector 22 protrudes from the ends of the positive electrode sheets 20 and 21. Further, the non-aqueous electrolyte batteries according to Comparative Examples 1 and 2 have the same characteristics at light load as compared with the non-aqueous electrolyte batteries according to Examples, but the characteristics at medium load are clear. A decrease is observed. This is because in a portion where the positive electrode sheets 20 and 21 are not provided on one surface of the current collector 22, the adhesion between the positive electrode sheets 20 and 21 and the current collector 22 is somewhat inferior, so that the current collection efficiency is reduced.
[0062]
On the other hand, like the non-aqueous electrolyte batteries of Examples 1, 2, and 3, the offset width W of the inner and outer positive electrode sheets 20 and 21 related to the wound end portion is 1/1 / th of the thickness L of the positive electrode sheet. No short circuit occurred at all when the position was displaced within the range of 2 to 2 times. This is because, by displacing the positive electrode sheets 20 and 21, the width of the wound end portion E of the positive electrode sheet 21 on the outer peripheral side in the outward direction is suppressed to be small, and the damage to the separator 5 can be successfully eliminated. It depends on. Further, it can be seen from Examples 2 and 3 that if the shift width W is in the range of not less than の and not more than twice the thickness L of the positive electrode sheets 20 and 21, there is no problem in medium load characteristics.
[0063]
According to Example 4, even if the winding end portions E of the inner and outer peripheral positive electrode sheets 20 and 21 are aligned, if the thin portion 27 is provided as shown in FIG. 5, no short circuit occurs and the battery characteristics are good. It can be seen that it is.
[Brief description of the drawings]
FIG. 1 is a cross-sectional plan view of a nonaqueous electrolyte battery according to a first embodiment of the present invention.
FIG. 2 is a vertical sectional front view of the nonaqueous electrolyte battery of the present invention.
FIG. 3 is a diagram for explaining a method of manufacturing an electrode wound body.
FIG. 4 is a cross-sectional plan view of a nonaqueous electrolyte battery according to a second embodiment of the present invention.
FIG. 5 is a cross-sectional plan view of a nonaqueous electrolyte battery according to a third embodiment of the present invention.
FIG. 6 is a cross-sectional plan view of a nonaqueous electrolyte battery according to a fourth embodiment of the present invention.
FIG. 7 is a cross-sectional plan view of a conventional nonaqueous electrolyte battery.
[Explanation of symbols]
1 Non-aqueous electrolyte battery
2 Exterior cans
3 Positive electrode
4 Negative electrode
5 Separator
6. Electrode wound body
20 Positive electrode sheet located on inner side
21 Positive electrode sheet located on the outer peripheral side
22 current collector
S Winding start end of positive electrode
E Winding end of positive electrode
W deviation width
L Thickness of positive electrode sheet

Claims (4)

上方開口部を有する有底円筒状の外装缶内に、シート状の正極と負極とをセパレータを介して捲回してなる電極捲回体と、非水電解液とを収容してなる円筒形の非水電解液電池であって、
前記電極捲回体は、前記正極の捲回始端部と捲回末端部とで規定される捲回数が１．６周以上、２．５周以下となるように正負極およびセパレータを捲回してなるものであって、全体として略円柱形状に成形されており、
前記正極は、同一の厚み寸法を有する２枚の正極シートと、これら正極シートの間に介在された集電体とを含み、電極捲回体の作成時において、該正極シートと集電体は、捲回始端部のみを固定した状態で捲回されており、
各正極シートは、正極活物質を０．５ｍｍ以上、２ｍｍ以下の厚み寸法を有するシート状に成形してなるものであり、
前記電極捲回体の最外周において、前記正極を構成する２枚の正極シートは、その捲回末端部が不揃いの位置ずれ状態とされており、
両正極シートの捲回末端部のずれ幅が、正極シートの厚み寸法の１／２以上、２倍以下に設定されていることを特徴とする非水電解液電池。An electrode wound body formed by winding a sheet-shaped positive electrode and a negative electrode through a separator in a bottomed cylindrical outer can having an upper opening, and a cylindrical shape containing a non-aqueous electrolyte. A non-aqueous electrolyte battery,
The electrode winding body is formed by winding the positive and negative electrodes and the separator so that the number of turns defined by the winding start end and the winding end of the positive electrode is 1.6 or more and 2.5 or less. It is molded into a substantially cylindrical shape as a whole,
The positive electrode includes two positive electrode sheets having the same thickness dimension, and a current collector interposed between the positive electrode sheets, and when the electrode wound body is formed, the positive electrode sheet and the current collector are , Is wound with only the winding start end fixed,
Each positive electrode sheet is formed by molding a positive electrode active material into a sheet having a thickness of 0.5 mm or more and 2 mm or less,
At the outermost periphery of the electrode winding body, the two positive electrode sheets constituting the positive electrode have winding end portions that are in irregular misalignment,
A nonaqueous electrolyte battery, wherein the offset width of the wound end portions of both positive electrode sheets is set to be not less than １ ／ and not more than twice the thickness dimension of the positive electrode sheets. 前記電極捲回体の最外周において、内周側に位置する正極シートの捲回末端部が、外周側に位置する正極シートの捲回末端部よりも長く延出された位置ずれ状態にある請求項１記載の非水電解液電池。In the outermost periphery of the electrode winding body, the wound end portion of the positive electrode sheet located on the inner peripheral side is in a misaligned state extended longer than the wound terminal end of the positive electrode sheet located on the outer peripheral side. Item 2. The non-aqueous electrolyte battery according to Item 1. 上方開口部を有する有底円筒状の外装缶内に、シート状の正極と負極とをセパレータを介して捲回してなる電極捲回体と、非水電解液とを収容してなる円筒形の非水電解液電池であって、
前記電極捲回体は、前記正極の捲回始端部と捲回末端部とで規定される捲回数が１．６周以上、２．５周以下となるように正負極およびセパレータを捲回してなるものであって、全体として略円柱形状に成形されており、
前記正極は、同一の厚み寸法を有する２枚の正極シートと、これら正極シートの間に介在された集電体とを含み、電極捲回体の作成時において、該正極シートと集電体は、捲回始端部のみを固定した状態で捲回されており、
各正極シートは、正極活物質を０．５ｍｍ以上、２ｍｍ以下の厚み寸法を有するシート状に成形してなるものであり、
前記電極捲回体の最外周において、外周側に位置する正極シートの捲回末端部に、他よりも厚みの薄い薄肉部を形成してあることを特徴とする非水電解液電池。An electrode wound body formed by winding a sheet-shaped positive electrode and a negative electrode through a separator in a bottomed cylindrical outer can having an upper opening, and a cylindrical shape containing a non-aqueous electrolyte. A non-aqueous electrolyte battery,
The electrode winding body is formed by winding the positive and negative electrodes and the separator so that the number of turns defined by the winding start end and the winding end of the positive electrode is 1.6 or more and 2.5 or less. It is molded into a substantially cylindrical shape as a whole,
The positive electrode includes two positive electrode sheets having the same thickness dimension, and a current collector interposed between the positive electrode sheets, and when the electrode wound body is formed, the positive electrode sheet and the current collector are , Is wound with only the winding start end fixed,
Each positive electrode sheet is formed by molding a positive electrode active material into a sheet having a thickness of 0.5 mm or more and 2 mm or less,
A nonaqueous electrolyte battery, characterized in that a thinner portion having a smaller thickness than other portions is formed at the outermost periphery of the electrode wound body at the wound end of the positive electrode sheet located on the outer periphery side. 上方開口部を有する有底円筒状の外装缶内に、シート状の正極と負極とをセパレータを介して捲回してなる電極捲回体と、非水電解液とを収容してなる円筒形の非水電解液電池であって、
前記電極捲回体は、前記正極の捲回始端部と捲回末端部とで規定される捲回数が１．６周以上、２．５周以下となるように正負極およびセパレータを捲回してなるものであって、全体として略円柱形状に成形されており、
前記正極は、同一の厚み寸法を有する２枚の正極シートと、これら正極シートの間に介在された集電体とを含み、電極捲回体の作成時において、該正極シートと集電体は、捲回始端部のみを固定した状態で捲回されており、
各正極シートは、正極活物質を０．５ｍｍ以上、２ｍｍ以下の厚み寸法を有するシート状に成形してなるものであり、
前記電極捲回体の最外周において、外周側に位置する正極シートの捲回末端部の外側縁が、面取り形成されていることを特徴とする非水電解液電池。An electrode wound body formed by winding a sheet-shaped positive electrode and a negative electrode through a separator in a bottomed cylindrical outer can having an upper opening, and a cylindrical shape containing a non-aqueous electrolyte. A non-aqueous electrolyte battery,
The electrode winding body is formed by winding the positive and negative electrodes and the separator so that the number of turns defined by the winding start end and the winding end of the positive electrode is 1.6 or more and 2.5 or less. It is molded into a substantially cylindrical shape as a whole,
The positive electrode includes two positive electrode sheets having the same thickness dimension, and a current collector interposed between the positive electrode sheets, and when the electrode wound body is formed, the positive electrode sheet and the current collector are , Is wound with only the winding start end fixed,
Each positive electrode sheet is formed by molding a positive electrode active material into a sheet having a thickness of 0.5 mm or more and 2 mm or less,
A nonaqueous electrolyte battery, wherein an outer edge of a wound end portion of a positive electrode sheet located on an outer peripheral side is chamfered at an outermost periphery of the electrode wound body.
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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009266750A (en) * 2008-04-28 2009-11-12 Hitachi Maxell Ltd Nonaqueous electrolyte battery
JP2015181112A (en) * 2015-04-21 2015-10-15 トヨタ自動車株式会社 Secondary battery, manufacturing method thereof, and method for manufacturing negative electrode sheet used for secondary battery
CN111213278A (en) * 2017-10-27 2020-05-29 三洋电机株式会社 Method for manufacturing nonaqueous electrolyte secondary battery
CN113540579A (en) * 2021-06-07 2021-10-22 厦门海辰新能源科技有限公司 Battery cell winding method and battery cell
CN114175366A (en) * 2019-09-26 2022-03-11 三洋电机株式会社 Secondary battery
CN114420887B (en) * 2022-01-18 2024-05-28 三一技术装备有限公司 Pole piece, diaphragm, lamination, battery core manufacturing process and battery

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009266750A (en) * 2008-04-28 2009-11-12 Hitachi Maxell Ltd Nonaqueous electrolyte battery
JP2015181112A (en) * 2015-04-21 2015-10-15 トヨタ自動車株式会社 Secondary battery, manufacturing method thereof, and method for manufacturing negative electrode sheet used for secondary battery
CN111213278A (en) * 2017-10-27 2020-05-29 三洋电机株式会社 Method for manufacturing nonaqueous electrolyte secondary battery
CN111213278B (en) * 2017-10-27 2023-06-30 三洋电机株式会社 Method for manufacturing nonaqueous electrolyte secondary battery
CN114175366A (en) * 2019-09-26 2022-03-11 三洋电机株式会社 Secondary battery
CN113540579A (en) * 2021-06-07 2021-10-22 厦门海辰新能源科技有限公司 Battery cell winding method and battery cell
CN114420887B (en) * 2022-01-18 2024-05-28 三一技术装备有限公司 Pole piece, diaphragm, lamination, battery core manufacturing process and battery

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