JP3842925B2

JP3842925B2 - Cylindrical battery

Info

Publication number: JP3842925B2
Application number: JP18080699A
Authority: JP
Inventors: 英樹北尾; 直哉中西; 俊之能間; 育郎米津
Original assignee: Sanyo Electric Co Ltd
Current assignee: Sanyo Electric Co Ltd
Priority date: 1999-06-25
Filing date: 1999-06-25
Publication date: 2006-11-08
Anticipated expiration: 2019-06-25
Also published as: JP2001015167A

Description

【０００１】
【発明の属する技術分野】
本発明は、筒状の電池缶の内部に巻き取り電極体が収容されて、電池缶に取り付けられた電極端子機構から巻き取り電極体の発生電力を取り出すことが可能な筒型電池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。
例えば電気自動車に用いられる比較的大きな容量の円筒型リチウム二次電池は、図４に示す様に、筒体(11)の開口部に蓋体(12)を溶接固定してなる円筒状の電池缶(１)の内部に、巻き取り電極体(２)を収容して構成されている。蓋体(12)には、電極端子機構(９)が取り付けられており、巻き取り電極体(２)と電極端子機構(９)とが複数本の集電タブ(３)により互いに接続されて、巻き取り電極体(２)が発生する電力を電極端子機構(９)から外部に取り出すことが可能となっている。又、蓋体(12)にはバネ復帰式のガス排出弁(13)が取り付けられている。
尚、筒体(11)の他方の開口部に固定された蓋体(図示省略)にも同じ構成の電極端子機構が取り付けられて、両電極端子機構が正負一対を為している。
【０００３】
巻き取り電極体(２)は、リチウム複合酸化物を含む正極(23)と炭素材料を含む負極(21)の間に、非水電解液が含浸されたセパレータ(22)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。巻き取り電極体(２)の正極(23)及び負極(21)からは夫々複数本の集電タブ(３)が引き出され、極性が同じ複数本の集電タブ(３)の先端部(31)が１つの電極端子機構(９)に接続されている。
【０００４】
尚、図４は、一部の集電タブの先端部が電極端子機構(９)に接続されている状態を示し、他の集電タブについては、電極端子機構(９)との接続部を図示省略している。
又、電池缶(１)の内部には、筒体(11)の内周面及び蓋体(12)の内面に沿って、巻き取り電極体(２)との電気的絶縁を図るための絶縁部材が配備されるが、図示省略している。
【０００５】
電極端子機構(９)は、電池缶(１)の蓋体(12)を貫通して取り付けられたネジ部材(91)を具え、該ネジ部材(91)の基端部にはフランジ部(92)が形成されている。蓋体(12)の貫通孔には、例えばポリプロピレン製の絶縁パッキン(93)が装着され、蓋体(12)と締結部材(91)の間の電気的絶縁性とシール性が保たれている。ネジ部材(91)には、筒体(11)の外側からワッシャ(94)が嵌められると共に、第１ナット(95)及び第２ナット(96)が螺合している。第１ナット(95)を締め付けて、ネジ部材(91)のフランジ部(92)とワッシャ(94)によって絶縁パッキン(93)を挟圧することにより、シール性を高めている。
前記複数本の集電タブ(３)の先端部(31)は、ネジ部材(91)のフランジ部(92)の裏面に、スポット溶接或いは超音波溶接によって連結されている。
【０００６】
【発明が解決しようとする課題】
しかしながら、従来のリチウムイオン二次電池においては、特に電気自動車の電源として用いた場合、外部から振動や衝撃を受けることによって、電池缶(１)内で巻き取り電極体(２)が移動し、電池缶(１)の内壁に衝突して、正極(23)や負極(21)から電極活物質の一部が剥がれ落ちる虞れがある。
正極(23)や負極(21)から電極活物質が剥がれ落ちると、電池の内部抵抗が増加して、電池出力が低下する問題を生じる。
【０００７】
そこで、巻き取り電極体の中央部に巻き芯を固定し、電池缶の両端部に取り付けられた一対の電極端子機構によって、該巻き芯を両側から挟持することにより、電池缶内に巻き取り電極体を固定する方法が知られている(例えば特開平9-92335号)。
しかしながら、該方法においては、巻き取り電極体の中央部に巻き芯を固定するために、巻き取り電極体の重量が増大し、電池の重量エネルギー密度が低下する問題があった。
【０００８】
そこで本発明の目的は、電池の重量エネルギー密度を低下させることなく電池缶内に巻き取り電極体を固定することが出来る、簡易な構成の筒型電池を提供することである。
【０００９】
【課題を解決する為の手段】
本発明に係る筒型電池は、筒体(11)の開口部に蓋体(12)を固定してなる電池缶(１)の内部に、巻き取り電極体(２)を具え、巻き取り電極体(２)が発生する電力を電極端子機構(４)から外部に取り出すものであって、電極端子機構(４)と接続された巻き取り電極体(２)の端部には、筒状の絶縁キャップ部材(６)が装着され、該絶縁キャップ部材(６)は、電池缶(１)の筒体(11)の内周面と巻き取り電極体(２)の外周面の間に緊密若しくは略緊密に嵌まる肉厚を有する筒部(61)を具え、巻き取り電極体 ( ２ ) の外周面には、巻き取り電極体 ( ２ ) の巻き軸方向の全長Ｌの５％以上の長さ範囲にて、絶縁キャップ部材 ( ６ ) の筒部 (61) の内周面が密着している。
【００１０】
上記本発明の筒型電池においては、電池缶(１)の筒体(11)の内周面と巻き取り電極体(２)の外周面との間に、絶縁キャップ部材(６)の筒部(61)が緊密若しくは略緊密に嵌まることによって、電池缶(１)内の巻き取り電極体(２)の外周面が周囲から拘束されることとなる。
従って、外部から振動や衝撃が加わったとしても、電池缶(１)内にて巻き取り電極体(２)が大きく移動する虞れはなく、よって、正極(23)や負極(21)から電極活物質が剥がれ落ちることはない。
又、巻き取り電極体 ( ２ ) の外周面には、絶縁キャップ部材 ( ６ ) の筒部 (61) の内周面が充分な面積で密着しているので、巻き取り電極体 ( ２ ) の外周面に作用する単位面積当たりの圧力を低く抑えた上で、巻き取り電極体 ( ２ ) の外周面に対して充分な大きさの挟圧力を与えることが出来る。
【００１１】
ここで、絶縁キャップ部材(６)は電気絶縁性を有しており、巻き取り電極体(２)と電池缶(１)の間の電気絶縁を図る部材を兼ねているので、従来の絶縁部材は省略することが出来る。
従って、本発明の実施によって電池の重量が増大することはなく、重量エネルギー密度は高い値に維持される。
【００１２】
具体的構成において、絶縁キャップ部材(６)は、筒部(61)の端部に、電池缶(１)の蓋体(12)の内面に沿って拡がる平板部(62)を一体に具え、該平板部(62)が電極端子機構(４)によって挟持されている。
該具体的構成においては、絶縁キャップ部材(６)の平板部(62)が電極端子機構(４)に挟持されることによって、絶縁キャップ部材(６)が電池缶(１)の蓋体(12)に固定されることになる。
絶縁キャップ部材(６)の平板部(62)によって、巻き取り電極体(２)と電池缶(１)の蓋体(12)の間の電気的絶縁が図られるので、従来の絶縁部材は省略することが出来る。
【００１３】
又、絶縁キャップ部材(６)の材質としては、ポリプロピレン、ポリエチレン、ポリテトラフルオロエチレンの何れかを採用することが出来る。
これによって、絶縁キャップ部材(６)が電池缶(１)中の電解液等と化学反応を起こすことない。
【００１４】
更に具体的な構成において、絶縁キャップ部材(６)の筒部(61)の肉厚は、絶縁キャップ部材(６)を嵌める前の状態において電池缶(１)の筒体(11)の内周面と巻き取り電極体(２)の外周面との間に形成される隙間寸法の０.９倍以上、１.２倍以下に形成されている。
これによって、電池缶(１)内の巻き取り電極体(２)の振動に対して充分な拘束力を与えることが出来ると共に、電池缶(１)の内周面と巻き取り電極体(２)の外周面の間へ絶縁キャップ部材(６)の筒部(61)を無理なく嵌入せしめることが可能となる。
【００１６】
又、更に具体的な構成において、絶縁キャップ部材(６)の筒部(61)は、その内周面の先端部にテーパ面 (63) を有して、巻き取り電極体(２)に嵌合する端部の先端が鋭角に尖っている。
これによって、電池缶(１)の内周面と巻き取り電極体(２)の外周面との間の狭い空間へ、絶縁キャップ部材(６)の筒部(61)を容易に嵌入せしめることが出来る。
【００１７】
【発明の効果】
本発明に係る筒型電池によれば、従来の絶縁部材を兼ねた絶縁キャップ部材によって、電池缶内に巻き取り電極体を拘持する方式を採用しているので、電池の重量エネルギー密度を低下させることなく、簡易な構造で巻き取り電極体を固定することが出来る。
【００１８】
【発明の実施の形態】
以下、本発明を円筒型のリチウムイオン二次電池に実施の形態につき、図面に沿って具体的に説明する。
本発明に係るリチウムイオン二次電池は、図１及び図２に示す如く、筒体(11)の両開口部に蓋体(12)(12)をそれぞれ溶接固定してなる円筒状のアルミニウム製電池缶(１)を具え、該電池缶(１)の内部には、巻き取り電極体(２)を収容している。尚、電池缶(１)の外径は５７ｍｍ、長さは２２０ｍｍである。
【００１９】
巻き取り電極体(２)は、正極集電体となるアルミニウム箔の表面にリチウム複合酸化物を含む正極層を形成してなる正極と、負極集電体となる銅箔の表面に炭素粉末を含む負極層を形成してなる負極との間に、非水電解液が含浸されたセパレータを介在させて、これらを渦巻き状に巻回したものであって、正極からは複数本のアルミニウム製の集電タブ(３)が引き出されている。又、負極からは複数本の銅製の集電タブ(３)が引き出されている。
【００２０】
電池缶(１)の両端部にはそれぞれ、ポリプロピレンからなる円筒状の絶縁キャップ部材(６)が装着され、これによって、巻き取り電極体(２)と電池缶(１)の間の電気絶縁が図られると共に、電池缶(１)内に巻き取り電極体(２)が固定されている。
【００２１】
電池缶(１)の各蓋体(12)には、電極端子機構(４)が取り付けられており、巻き取り電極体(２)と各電極端子機構(４)とがそれぞれ、前記複数本の集電タブ(３)により互いに接続されて、巻き取り電極体(２)が発生する電力を一対の電極端子機構(４)(４)から外部に取り出すことが可能となっている。
【００２２】
又、蓋体(12)には、図３に示す如く、電極端子機構(４)が貫通すべき断面円形の中央孔(18)が開設され、中央孔(18)の両側には、組立時に電解液注入のために用いるねじ孔(17)と、リング部材(14a)及び弁膜(14b)からなる圧力開放型のガス排出弁(14)を取り付けるための圧力逃し孔(15)が開設されている。尚、電解液の注入後、ねじ孔(17)にはねじ栓(16)がねじ込まれる。又、ガス排出弁(14)は、蓋体(12)の圧力逃し孔(15)の開口縁に溶接固定される。
【００２３】
正極側の電極端子機構(４)は、蓋体(12)を貫通して取り付けられるアルミニウム製の端子部材(５)を具えている。端子部材(５)は、蓋体(12)に開設された中央孔(18)を貫通する円柱部(52)と、円柱部(52)に上向きに突設されたねじ軸部(53)と、円柱部(52)の下端部に形成されたフランジ部(51)とから構成され、フランジ部(51)の上面には、フッ素樹脂製のＯリング(72)が嵌まるリング溝(54)が凹設されている。
【００２４】
又、端子部材(５)の背面には、ねじ孔(5a)が凹設されており、該ねじ孔(5a)には、六角頭部(56)及びねじ部(57)からなるねじ部材(55)がねじ込まれる。
そして、端子部材(５)のフランジ部(51)とねじ部材(55)の六角頭部(56)の間に、前記複数本の集電タブ(３)の先端部を挟み込んで固定するようになっている(図２参照)。
【００２５】
絶縁キャップ部材(６)は、電池缶(１)の筒体(11)の内周面に密着する円筒部(61)と、電池缶(１)の蓋体(12)の内面に密着する平板部(62)とを一体に具え、円筒部(61)の肉厚は、電池缶(１)の筒体(11)の内周面と巻き取り電極体(２)の外周面との間に円筒部(61)が緊密状態で嵌まることとなる様、適当な大きさに形成されている。
【００２６】
絶縁キャップ部材(６)の平板部(62)の中央部には、端子部材(５)の円柱部(52)が貫通すべき中央孔(64)が開設されると共に、中央孔(64)の両側には、蓋体(12)の圧力逃がし孔(15)及びねじ孔(17)に合致すべき２つの貫通孔(65)(66)が開設されている。又、平板部(62)の上面には、中央孔(64)を包囲して、フッ素樹脂製のＯリング(73)が嵌まるリング溝(67)が凹設されている。
絶縁キャップ部材(６)の円筒部(61)には、その内周面の下端部に、下方に向かって拡大するテーパ面(63)が形成されており、これによって、円筒部(61)の先端が鋭角に尖っている。
【００２７】
又、電極端子機構(４)には、蓋体(12)の中央孔(18)に嵌まる第１パッキン部材(７)と、蓋体(12)の中央孔(18)の開口縁に嵌まる第２パッキン部材(71)とが装備され、両パッキン部材(７)(71)が互いに係合して、蓋体(12)の中央孔(18)と端子部材(５)との間に気密性を与えている。
尚、絶縁キャップ部材(６)の平板部(62)の内面や蓋体(12)の内面にも、それぞれ前記Ｏリング(72)(73)が嵌まるリング溝(図示省略)が凹設されている。
【００２８】
蓋体(12)の中央孔(18)から突出する端子部材(５)のねじ軸部(53)には、アルミニウム製のワッシャ(81)が嵌められ、更にその上部に、アルミニウム製のナット(８)が螺合され、締め付けられる。
負極側の電極端子機構(４)も同様の構成を有しているが、端子部材(５)やねじ部材(55)がニッケルによって形成されている。
【００２９】
上記円筒型リチウム二次電池の組立工程においては、電池缶(１)を構成すべき蓋体(12)に電極端子機構(４)を取り付ける一方、筒体(11)の内部に巻き取り電極体(２)を装入した状態で、巻き取り電極体(２)から伸びる複数本の集電タブ(３)の先端部を端子部材(５)のフランジ部(51)とねじ部材(55)の六角頭部(56)の間に挟み込み、ねじ部材(55)を締め付ける。
【００３０】
次に、絶縁キャップ部材(６)の円筒部(61)を、電池缶(１)の筒体(11)の内周面と巻き取り電極体(２)の外周面との間の空間へ嵌入せしめると共に、蓋体(12)を筒体(11)の開口部に被せる。この際、絶縁キャップ部材(６)の円筒部(61)の先端が尖っているため、該先端を前記空間へ容易に差し込むことが出来る。
その後、筒体(11)に蓋体(12)を溶接固定する。そして、蓋体(12)のねじ孔(17)から電池缶(１)内に電解液を注入した後、ねじ孔(17)にねじ栓(16)をねじ込み、更にナット(８)を増し締めして、組立を完了する。
これによって、図１に示す円筒型のリチウムイオン二次電池が完成する。
【００３１】
上記本発明の円筒型リチウムイオン二次電池においては、電池缶(１)の筒体(11)の内周面と巻き取り電極体(２)の外周面との間に、絶縁キャップ部材(６)の円筒部(61)が緊密に嵌まることによって、電池缶(１)内の巻き取り電極体(２)の外周面が周囲から強く挟圧されることとなり、この結果、電池缶(１)内に巻き取り電極体(２)が固定される。
従って、外部から振動や衝撃が加わったとしても、電池缶(１)内にて巻き取り電極体(２)が移動する虞れはなく、よって、正極(23)や負極(21)から電極活物質が剥がれ落ちることはない。
【００３２】
【実施例】
上記本発明に係るリチウムイオン二次電池を以下の工程により試作し、その性能を確認した。
【００３３】
(正極の作製)
正極活物質としてのＬｉＣｏＯ_２粉末と導電剤としての人造黒鉛を重量比９：１で混合して、正極合剤を得た。この正極合剤と、結着剤である５重量％のポリフッ化ビニリデン(ＰＶｄＦ)をＮ−メチル−２−ピロリドン(ＮＭＰ)に溶解させたＮＭＰ溶液とを、固形分重量比９５：５で混練し、スラリーを調製した。このスラリーを、厚さ２０μｍのアルミニウム箔の両面にドクターブレード法によって塗布し、正極を作製した。
【００３４】
(負極の作製)
黒鉛粉末と、ＰＶｄＦをＮＭＰに溶解させたＮＭＰ溶液とを、黒鉛粉末とＰＶｄＦの重量比が８５：１５となるように混練して、スラリーを調整した。このスラリーを、厚さ２０μｍの銅箔の両面にドクターブレード法によって塗布し、負極を作製した。
【００３５】
(電解液の調製)
エチレンカーボネートとジエチルカーボネートを体積比１：１で混合した溶媒に、ＬｉＰＦ_６を１Ｍの割合で溶解し、電解液を調製した。
【００３６】
(電池の組立)
上記の様にして得られた正極と負極の間に、イオン透過性のポリプロピレン微多孔膜からなるセパレータを挟んで渦巻き状に巻回し、巻き取り電極体を構成した。そして、該巻き取り電極体を用いて、後述する１５種類の本発明電池Ａ、Ｃ〜Ｎと、比較例電池Ｂとを組み立てた。
【００３７】
本発明電池Ａ
本発明電池Ａにおいて、絶縁キャップ部材(６)を嵌入せしめる前の状態で電池缶(１)の筒体(11)の内周面と巻き取り電極体(２)の外周面との間に形成される隙間の寸法(以下、単に隙間寸法という)は、０.５ｍｍに設定されている
絶縁キャップ部材(６)は、円筒部(61)の肉厚Ｔを０.６ｍｍに形成した。従って、該肉厚Ｔの隙間寸法に対する比率は１.２となる。
又、絶縁キャップ部材(６)の円筒部(61)の先端角度を３０゜に形成すると共に、電池の組立後において巻き取り電極体(２)の外周面が１つの絶縁キャップ部材(６)の内周面によって直接に覆われることとなる円筒面領域の被覆率(Ｓ／Ｌ)が１０％となる様、絶縁キャップ部材(６)の寸法を決定した。
【００３８】
比較例電池
絶縁キャップ部材(６)が装備されていないこと以外は電池Ａと同様にして、比較例電池Ｂを作製した。
【００３９】
本発明電池Ｃ、Ｄ、Ｅ、Ｆ、Ｇ、Ｈ
絶縁キャップ部材(６)の円筒部(61)の肉厚Ｔが隙間寸法に対してそれぞれ０.６、０.８、０.９、１.０、１.３、１．５の比率を有していること以外は本発明電池Ａと同様にして、本発明電池Ｃ、Ｄ、Ｅ、Ｆ、Ｇ、Ｈを作製した。
【００４０】
電池Ｉ、Ｊ、及び本発明電池Ｋ、Ｌ、Ｍ、Ｎ
巻き取り電極体(２)の外周面の被覆率(Ｓ／Ｌ)がそれぞれ１％、３％、５％、１５％、２０％、３０％に設定されていること以外は本発明電池Ａと同様にして、電池Ｉ、Ｊ及び本発明電池Ｋ、Ｌ、Ｍ、Ｎを作製した。
【００４１】
振動試験
上記の各電池Ａ〜Ｍに対し、振幅０.８ｍｍを有して、掃引速度１Ｈｚ／ｍｉｎにて周波数が１０〜５５Ｈｚの範囲で変化するＸＹＺ軸方向の振動を、１００分間与えて、振動試験前後における１ｋＨｚ時の内部抵抗を測定した。
【００４２】
表１は、本発明電池Ａと比較例電池Ｂにおける振動試験前後の内部抵抗を表わしている。
【表１】

【００４３】
表１から明らかな様に、本発明電池Ａでは振動試験後に内部抵抗の増大は見られなかったが、比較例電池Ｂでは、内部抵抗が大幅に増大している。これは、比較例電池Ｂでは、電極缶内の巻き取り電極体の固定が不十分であったために、振動によって電極から活物質の一部が剥がれ落ちたためであると推定される。
【００４４】
表２は、本発明電池Ａ及びＣ〜Ｈにおける各部の寸法と、振動試験前後の内部抵抗を表わしている。
【表２】

【００４５】
表２から明らかな様に、本発明電池Ｅ、Ｆでは、振動試験後に内部抵抗の増大は見られなかったが、本発明電池Ｃ、Ｄでは、内部抵抗に若干の増大が発生している。これは、本発明電池Ｃ、Ｄでは、絶縁キャップ部材による巻き取り電極体の固定が不十分であったために、振動によって電極の活物質の一部が剥がれ落ちたためと推定される。
又、本発明電池Ｇ、Ｈにおいては、絶縁キャップ部材(６)の円筒部(61)の肉厚が過大であるために、該円筒部(61)を電池缶(１)の内周面と巻き取り電極体(２)の外周面の間へ無理に挿入することとなって、歩留まりが低下した。
【００４６】
従って、絶縁キャップ部材(６)の筒部(61)の肉厚Ｔは、電池缶(１)と巻き取り電極体(２)の間の隙間寸法の０.９倍以上、１.２倍以下に形成することが好ましいと言える。
尚、絶縁キャップ部材(６)の材質として、ポリエチレンやポリテトラフルオロエチレンを用いた場合にも、同様の結論が得られた。
【００４７】
表３は、本発明電池Ａ、電池Ｉ、Ｊ、及び本発明電池Ｋ〜Ｎにおける巻き取り電極体の外周面の被覆率と、振動試験前後の内部抵抗を表わしている。
【表３】

【００４８】
表３から明らかな様に、本発明電池Ｋ、Ｌ、Ｍ、Ｎでは、振動試験後も内部抵抗の増大は見られなかったが、電池Ｉ、Ｊでは、振動試験後に内部抵抗が増大した。これは、電池Ｉ、Ｊの様に５％未満の被覆率では、巻き取り電極体(２)に局所的な応力が作用して、セパレータ(22)に目詰まりが生じる等の問題が発生するためと考えられる。
従って、巻き取り電極体(２)の外周面の絶縁キャップ部材(６)による被覆率は５％以上に設定することが好ましいと言える。
尚、絶縁キャップ部材(６)の材質として、ポリエチレンやポリテトラフルオロエチレンを用いた場合にも、同様の結論が得られた。
【００４９】
尚、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、本発明は円筒型の二次電池のみならず、角筒型の二次電池や、筒型の一次電池に実施することも可能である。
【図面の簡単な説明】
【図１】本発明に係る円筒型二次電池の一部破断正面図である。
【図２】該二次電池の要部を拡大して示す断面図である。
【図３】電極端子機構及び絶縁キャップ部材の分解斜視図である。
【図４】従来の円筒型二次電池の断面図である。
【符号の説明】
(１) 電池缶
(11) 筒体
(12) 蓋体
(２) 巻き取り電極体
(３) 集電タブ
(４) 電極端子機構
(５) 端子部材
(６) 絶縁キャップ部材
(61) 円筒部
(62) 平板部
(63) テーパ面[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cylindrical battery in which a winding electrode body is housed inside a cylindrical battery can and the electric power generated by the winding electrode body can be taken out from an electrode terminal mechanism attached to the battery can. is there.
[0002]
[Prior art]
In recent years, lithium ion secondary batteries with high energy density have attracted attention as power sources for portable electronic devices and electric vehicles.
For example, as shown in FIG. 4, a cylindrical lithium secondary battery having a relatively large capacity used for an electric vehicle is a cylindrical battery in which a lid (12) is welded and fixed to an opening of a cylindrical body (11). The take-up electrode body (2) is accommodated inside the can (1). An electrode terminal mechanism (9) is attached to the lid (12), and the winding electrode body (2) and the electrode terminal mechanism (9) are connected to each other by a plurality of current collecting tabs (3). The electric power generated by the winding electrode body (2) can be taken out from the electrode terminal mechanism (9). A spring return type gas discharge valve (13) is attached to the lid (12).
An electrode terminal mechanism having the same configuration is also attached to a lid (not shown) fixed to the other opening of the cylindrical body (11), and both electrode terminal mechanisms form a positive and negative pair.
[0003]
The take-up electrode body (2) includes a separator (22) impregnated with a non-aqueous electrolyte between a positive electrode (23) containing a lithium composite oxide and a negative electrode (21) containing a carbon material. Is wound in a spiral shape. A plurality of current collecting tabs (3) are drawn out from the positive electrode (23) and the negative electrode (21) of the winding electrode body (2), respectively, and the tips (31) of the plurality of current collecting tabs (3) having the same polarity are drawn out. ) Is connected to one electrode terminal mechanism (9).
[0004]
FIG. 4 shows a state in which the tip ends of some of the current collecting tabs are connected to the electrode terminal mechanism (9), and the other current collecting tabs are connected to the electrode terminal mechanism (9). The illustration is omitted.
In addition, the battery can (1) has an insulation for electrical insulation from the winding electrode body (2) along the inner peripheral surface of the cylinder (11) and the inner surface of the lid (12). Although members are provided, they are not shown.
[0005]
The electrode terminal mechanism (9) includes a screw member (91) attached through the lid (12) of the battery can (1). A flange portion (92) is provided at the proximal end of the screw member (91). ) Is formed. In the through hole of the lid (12), for example, an insulating packing (93) made of polypropylene is mounted, and the electrical insulation and sealing performance between the lid (12) and the fastening member (91) are maintained. . A washer (94) is fitted to the screw member (91) from the outside of the cylindrical body (11), and a first nut (95) and a second nut (96) are screwed together. The first nut (95) is tightened, and the insulating packing (93) is clamped by the flange portion (92) and the washer (94) of the screw member (91), thereby improving the sealing performance.
The tip portions (31) of the plurality of current collecting tabs (3) are connected to the back surface of the flange portion (92) of the screw member (91) by spot welding or ultrasonic welding.
[0006]
[Problems to be solved by the invention]
However, in a conventional lithium ion secondary battery, especially when used as a power source for an electric vehicle, the winding electrode body (2) moves in the battery can (1) by receiving vibration or impact from the outside. There is a possibility that a part of the electrode active material is peeled off from the positive electrode (23) or the negative electrode (21) by colliding with the inner wall of the battery can (1).
When the electrode active material is peeled off from the positive electrode (23) or the negative electrode (21), the internal resistance of the battery increases, causing a problem that the battery output decreases.
[0007]
Therefore, the winding core is fixed to the central portion of the winding electrode body, and the winding core is sandwiched from both sides by a pair of electrode terminal mechanisms attached to both ends of the battery can, so that the winding electrode is placed in the battery can. A method for fixing a body is known (for example, JP-A-9-92335).
However, in this method, since the winding core is fixed to the central portion of the winding electrode body, there is a problem that the weight of the winding electrode body increases and the weight energy density of the battery decreases.
[0008]
Accordingly, an object of the present invention is to provide a cylindrical battery having a simple configuration capable of fixing a winding electrode body in a battery can without reducing the weight energy density of the battery.
[0009]
[Means for solving the problems]
The cylindrical battery according to the present invention includes a winding electrode body (2) inside a battery can (1) formed by fixing a lid body (12) to an opening of a cylindrical body (11). The electric power generated by the body (2) is taken out from the electrode terminal mechanism (4), and at the end of the winding electrode body (2) connected to the electrode terminal mechanism (4), a cylindrical shape is provided. An insulating cap member (6) is attached, and the insulating cap member (6) is tightly or between the inner peripheral surface of the cylindrical body (11) of the battery can (1) and the outer peripheral surface of the winding electrode body (2). cylindrical portion (61) comprises having a full wall thickness tightly fitted substantially on the outer peripheral surface of the wound electrode body (2), 5% or more of the length of the total length of the winding axis direction of the wound electrode body (2) L In this range, the inner peripheral surface of the cylindrical portion (61) of the insulating cap member ( 6 ) is in close contact.
[0010]
In the cylindrical battery of the present invention, the cylindrical portion of the insulating cap member (6) is disposed between the inner peripheral surface of the cylindrical body (11) of the battery can (1) and the outer peripheral surface of the winding electrode body (2). When (61) fits closely or substantially tightly, the outer peripheral surface of the winding electrode body (2) in the battery can (1) is restrained from the periphery.
Therefore, even if a vibration or impact is applied from the outside, there is no possibility that the winding electrode body (2) moves greatly in the battery can (1). Therefore, the electrode from the positive electrode (23) or the negative electrode (21) The active material does not peel off.
Further, on the outer circumferential surface of the wound electrode body (2), since the inner peripheral surface of the cylindrical portion of the insulating cap member (6) (61) is in close contact with a sufficient area, the winding electrode body (2) A sufficiently large clamping pressure can be applied to the outer peripheral surface of the winding electrode body ( 2 ) while keeping the pressure per unit area acting on the outer peripheral surface low .
[0011]
Here, since the insulating cap member (6) has electric insulation and serves also as a member for electric insulation between the winding electrode body (2) and the battery can (1), the conventional insulating member. Can be omitted.
Therefore, the weight of the battery is not increased by the practice of the present invention, and the weight energy density is maintained at a high value.
[0012]
In a specific configuration, the insulating cap member (6) integrally includes a flat plate portion (62) extending along the inner surface of the lid (12) of the battery can (1) at the end of the cylindrical portion (61), The flat plate portion (62) is clamped by the electrode terminal mechanism (4).
In this specific configuration, the insulating cap member (6) is sandwiched between the electrode terminal mechanism (4) by sandwiching the flat plate portion (62) of the insulating cap member (6) so that the lid (12) of the battery can (1). ) Will be fixed.
Since the flat plate portion (62) of the insulating cap member (6) provides electrical insulation between the winding electrode body (2) and the lid body (12) of the battery can (1), the conventional insulating member is omitted. I can do it.
[0013]
As the material of the insulating cap member (6), any of polypropylene, polyethylene, and polytetrafluoroethylene can be used.
Thereby, the insulating cap member (6) does not cause a chemical reaction with the electrolytic solution or the like in the battery can (1).
[0014]
In a more specific configuration, the thickness of the cylindrical portion (61) of the insulating cap member (6) is such that the inner periphery of the cylindrical body (11) of the battery can (1) before the insulating cap member (6) is fitted. The gap is formed between 0.9 times and 1.2 times as large as the gap formed between the surface and the outer peripheral surface of the winding electrode body (2).
As a result, a sufficient restraining force can be applied to the vibration of the winding electrode body (2) in the battery can (1), and the inner peripheral surface of the battery can (1) and the winding electrode body (2). It becomes possible to fit the cylindrical portion (61) of the insulating cap member (6) without difficulty between the outer peripheral surfaces.
[0016]
In a more specific configuration, the cylindrical portion (61) of the insulating cap member (6) has a tapered surface (63) at the tip of the inner peripheral surface thereof and is fitted to the winding electrode body (2). The tip of the joining end is sharp at an acute angle.
Thus, the cylindrical portion (61) of the insulating cap member (6) can be easily fitted into the narrow space between the inner peripheral surface of the battery can (1) and the outer peripheral surface of the winding electrode body (2). I can do it.
[0017]
【The invention's effect】
According to the cylindrical battery according to the present invention, a method in which the winding electrode body is held in the battery can by the insulating cap member that also serves as the conventional insulating member is used, so that the weight energy density of the battery is reduced. The winding electrode body can be fixed with a simple structure without making it.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings with respect to embodiments of a cylindrical lithium ion secondary battery.
As shown in FIGS. 1 and 2, the lithium ion secondary battery according to the present invention is made of cylindrical aluminum in which lids (12), (12) are welded and fixed to both openings of the cylinder (11). The battery can (1) is provided, and the winding electrode body (2) is accommodated in the battery can (1). The battery can (1) has an outer diameter of 57 mm and a length of 220 mm.
[0019]
The wound electrode body (2) comprises a positive electrode formed by forming a positive electrode layer containing a lithium composite oxide on the surface of an aluminum foil serving as a positive electrode current collector, and a carbon powder on the surface of a copper foil serving as a negative electrode current collector. A separator impregnated with a non-aqueous electrolyte is interposed between the negative electrode formed with the negative electrode layer, and these are wound in a spiral shape. The current collecting tab (3) is pulled out. Further, a plurality of copper current collecting tabs (3) are drawn out from the negative electrode.
[0020]
Cylindrical insulating cap members (6) made of polypropylene are attached to both ends of the battery can (1), whereby electrical insulation between the winding electrode body (2) and the battery can (1) is provided. As shown, the winding electrode body (2) is fixed in the battery can (1).
[0021]
An electrode terminal mechanism (4) is attached to each lid body (12) of the battery can (1), and each of the winding electrode body (2) and each electrode terminal mechanism (4) includes the plurality of the above-mentioned plurality. Connected to each other by the current collecting tab (3), the electric power generated by the winding electrode body (2) can be taken out from the pair of electrode terminal mechanisms (4) and (4).
[0022]
Further, as shown in FIG. 3, the lid (12) is provided with a central hole (18) having a circular cross section through which the electrode terminal mechanism (4) passes, and on both sides of the central hole (18) during assembly. A screw hole (17) used for electrolyte injection and a pressure relief hole (15) for mounting a pressure release type gas discharge valve (14) consisting of a ring member (14a) and a valve membrane (14b) are opened. Yes. In addition, after injection | pouring of electrolyte solution, a screw plug (16) is screwed in a screw hole (17). The gas discharge valve (14) is fixed by welding to the opening edge of the pressure relief hole (15) of the lid (12).
[0023]
The electrode terminal mechanism (4) on the positive electrode side includes an aluminum terminal member (5) attached through the lid (12). The terminal member (5) includes a cylindrical portion (52) that passes through a central hole (18) provided in the lid (12), and a screw shaft portion (53) that projects upward from the cylindrical portion (52). And a flange portion (51) formed at the lower end portion of the cylindrical portion (52). On the upper surface of the flange portion (51), a ring groove (54) in which an O-ring (72) made of fluororesin is fitted Is recessed.
[0024]
A screw hole (5a) is recessed in the back surface of the terminal member (5). The screw hole (5a) has a screw member (hexagonal head (56) and screw portion (57)). 55) is screwed.
The tip portions of the plurality of current collecting tabs (3) are sandwiched and fixed between the flange portion (51) of the terminal member (5) and the hexagonal head portion (56) of the screw member (55). (See FIG. 2).
[0025]
The insulating cap member (6) includes a cylindrical portion (61) that is in close contact with the inner peripheral surface of the cylindrical body (11) of the battery can (1) and a flat plate that is in close contact with the inner surface of the lid (12) of the battery can (1). The cylindrical portion (61) has a thickness between the inner peripheral surface of the cylindrical body (11) and the outer peripheral surface of the winding electrode body (2). The cylindrical part (61) is formed in an appropriate size so as to be fitted in a tight state.
[0026]
A central hole (64) through which the cylindrical part (52) of the terminal member (5) passes is formed in the central part of the flat plate part (62) of the insulating cap member (6). On both sides, two through holes (65) and (66) that should match the pressure relief holes (15) and screw holes (17) of the lid (12) are provided. In addition, a ring groove (67) is provided on the upper surface of the flat plate portion (62) so as to surround the central hole (64) and to receive an O-ring (73) made of a fluororesin.
The cylindrical portion (61) of the insulating cap member (6) is formed with a tapered surface (63) that expands downward at the lower end portion of the inner peripheral surface thereof. The tip is sharp.
[0027]
The electrode terminal mechanism (4) is fitted to the opening edge of the first packing member (7) that fits in the central hole (18) of the lid (12) and the central hole (18) of the lid (12). A second packing member (71), and the packing members (7) and (71) are engaged with each other so that the gap between the center hole (18) of the lid (12) and the terminal member (5) It is airtight.
Ring grooves (not shown) in which the O-rings (72) and (73) are fitted are respectively provided in the inner surface of the flat plate portion (62) of the insulating cap member (6) and the inner surface of the lid (12). ing.
[0028]
An aluminum washer (81) is fitted on the screw shaft (53) of the terminal member (5) protruding from the central hole (18) of the lid (12), and an aluminum nut ( 8) is screwed and tightened.
The electrode terminal mechanism (4) on the negative electrode side has the same configuration, but the terminal member (5) and the screw member (55) are made of nickel.
[0029]
In the assembly process of the cylindrical lithium secondary battery, the electrode terminal mechanism (4) is attached to the lid (12) that is to constitute the battery can (1), while the winding electrode body is placed inside the cylinder (11). With the (2) inserted, the tips of the current collecting tabs (3) extending from the winding electrode body (2) are connected to the flanges (51) of the terminal member (5) and the screw members (55). Clamp between the hexagon heads (56) and tighten the screw member (55).
[0030]
Next, the cylindrical portion (61) of the insulating cap member (6) is inserted into the space between the inner peripheral surface of the cylindrical body (11) of the battery can (1) and the outer peripheral surface of the winding electrode body (2). At the same time, the lid (12) is placed over the opening of the cylinder (11). At this time, since the tip of the cylindrical portion (61) of the insulating cap member (6) is sharp, the tip can be easily inserted into the space.
Thereafter, the lid (12) is fixed by welding to the cylinder (11). After injecting the electrolyte into the battery can (1) from the screw hole (17) of the lid (12), the screw plug (16) is screwed into the screw hole (17), and the nut (8) is further tightened. Then, the assembly is completed.
Thereby, the cylindrical lithium ion secondary battery shown in FIG. 1 is completed.
[0031]
In the cylindrical lithium ion secondary battery of the present invention, an insulating cap member (6) is provided between the inner peripheral surface of the cylindrical body (11) of the battery can (1) and the outer peripheral surface of the winding electrode body (2). ) Is tightly fitted, the outer peripheral surface of the take-up electrode body (2) in the battery can (1) is strongly pinched from the periphery. As a result, the battery can (1 The take-up electrode body (2) is fixed in the bracket.
Therefore, even if a vibration or impact is applied from the outside, there is no possibility that the wound electrode body (2) moves in the battery can (1), and therefore the electrode active from the positive electrode (23) or the negative electrode (21). The material will not come off.
[0032]
【Example】
The lithium ion secondary battery according to the present invention was prototyped according to the following steps, and its performance was confirmed.
[0033]
(Preparation of positive electrode)
LiCoO ₂ powder as a positive electrode active material and artificial graphite as a conductive agent were mixed at a weight ratio of 9: 1 to obtain a positive electrode mixture. This positive electrode mixture and an NMP solution prepared by dissolving 5% by weight of polyvinylidene fluoride (PVdF) as a binder in N-methyl-2-pyrrolidone (NMP) at a solid content weight ratio of 95: 5 And a slurry was prepared. This slurry was applied to both surfaces of an aluminum foil having a thickness of 20 μm by a doctor blade method to produce a positive electrode.
[0034]
(Preparation of negative electrode)
The graphite powder and an NMP solution in which PVdF was dissolved in NMP were kneaded so that the weight ratio of the graphite powder and PVdF was 85:15 to prepare a slurry. This slurry was applied to both sides of a 20 μm thick copper foil by a doctor blade method to produce a negative electrode.
[0035]
(Preparation of electrolyte)
LiPF ₆ was dissolved at a ratio of 1M in a solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 1: 1 to prepare an electrolytic solution.
[0036]
(Battery assembly)
Between the positive electrode and the negative electrode obtained as described above, a separator made of an ion-permeable polypropylene microporous film was sandwiched and wound in a spiral shape to constitute a wound electrode body. And 15 types of this invention batteries A and C-N mentioned later and the comparative example battery B were assembled using this winding electrode body.
[0037]
Invention battery A
In the present invention battery A, it is formed between the inner peripheral surface of the cylindrical body (11) of the battery can (1) and the outer peripheral surface of the winding electrode body (2) in a state before the insulating cap member (6) is fitted. The insulating cap member (6), in which the gap dimension (hereinafter simply referred to as gap dimension) is set to 0.5 mm, has a cylindrical portion (61) having a thickness T of 0.6 mm. Accordingly, the ratio of the thickness T to the gap size is 1.2.
Further, the tip end angle of the cylindrical portion (61) of the insulating cap member (6) is formed to be 30 °, and the outer peripheral surface of the winding electrode body (2) after the assembly of the battery is one insulating cap member (6). The dimensions of the insulating cap member (6) were determined so that the coverage ratio (S / L) of the cylindrical surface region that would be directly covered by the inner peripheral surface was 10%.
[0038]
Comparative battery A comparative battery B was prepared in the same manner as the battery A, except that the insulating cap member (6) was not provided.
[0039]
Invention batteries C, D, E, F, G, H
The thickness T of the cylindrical portion (61) of the insulating cap member (6) has ratios of 0.6, 0.8, 0.9, 1.0, 1.3, and 1.5, respectively, with respect to the gap size. Inventive batteries C, D, E, F, G, and H were produced in the same manner as in the inventive battery A except for the above.
[0040]
Batteries I and J, and batteries K, L, M and N of the present invention
The battery A of the present invention, except that the coverage (S / L) of the outer peripheral surface of the wound electrode body (2) is set to 1%, 3%, 5%, 15%, 20%, and 30%, respectively. Similarly, batteries I and J and inventive batteries K, L, M and N were produced.
[0041]
Vibration test For each of the batteries A to M, vibrations in the XYZ axis directions having an amplitude of 0.8 mm and a frequency changing in the range of 10 to 55 Hz at a sweep speed of 1 Hz / min are 100 The internal resistance was measured at 1 kHz before and after the vibration test.
[0042]
Table 1 shows the internal resistance before and after the vibration test in the battery A of the present invention and the comparative battery B.
[Table 1]

[0043]
As is clear from Table 1, the battery A of the present invention did not show any increase in internal resistance after the vibration test, but the battery of Comparative Example B has a large increase in internal resistance. This is presumably because in Comparative Example Battery B, the winding electrode body in the electrode can was not sufficiently fixed, and part of the active material was peeled off from the electrode due to vibration.
[0044]
Table 2 shows the dimensions of each part in the present invention batteries A and C to H and the internal resistance before and after the vibration test.
[Table 2]

[0045]
As is clear from Table 2, the batteries E and F of the present invention did not show an increase in internal resistance after the vibration test, but the batteries C and D of the present invention show a slight increase in internal resistance. This is presumably because in the batteries C and D of the present invention, since the winding electrode body was not sufficiently fixed by the insulating cap member, part of the active material of the electrode was peeled off due to vibration.
In the batteries G and H of the present invention, since the thickness of the cylindrical portion (61) of the insulating cap member (6) is excessive, the cylindrical portion (61) is connected to the inner peripheral surface of the battery can (1). The yield was lowered by forcibly inserting it between the outer peripheral surfaces of the wound electrode body (2).
[0046]
Therefore, the thickness T of the cylindrical portion (61) of the insulating cap member (6) is not less than 0.9 times and not more than 1.2 times the gap dimension between the battery can (1) and the take-up electrode body (2). It can be said that it is preferable to form it.
The same conclusion was obtained when polyethylene or polytetrafluoroethylene was used as the material of the insulating cap member (6).
[0047]
Table 3 represents the coverage of the outer peripheral surface of the wound electrode body and the internal resistance before and after the vibration test in the present invention battery A , the batteries I and J, and the present invention batteries K to N.
[Table 3]

[0048]
As is apparent from Table 3, the batteries K, L, M, and N of the present invention did not increase the internal resistance after the vibration test, but the batteries I and J increased the internal resistance after the vibration test. This is because, when the coverage is less than 5% as in the case of the batteries I and J , local stress acts on the winding electrode body (2) and the separator (22) is clogged. This is probably because of this.
Accordingly, it can be said that the coverage of the outer peripheral surface of the winding electrode body (2) by the insulating cap member (6) is preferably set to 5% or more.
The same conclusion was obtained when polyethylene or polytetrafluoroethylene was used as the material of the insulating cap member (6).
[0049]
In addition, each part structure of this invention is not restricted to the said embodiment, A various deformation | transformation is possible within the technical scope as described in a claim. For example, the present invention can be implemented not only in a cylindrical secondary battery but also in a square tube type secondary battery and a cylindrical primary battery.
[Brief description of the drawings]
FIG. 1 is a partially broken front view of a cylindrical secondary battery according to the present invention.
FIG. 2 is an enlarged cross-sectional view showing a main part of the secondary battery.
FIG. 3 is an exploded perspective view of an electrode terminal mechanism and an insulating cap member.
FIG. 4 is a cross-sectional view of a conventional cylindrical secondary battery.
[Explanation of symbols]
(1) Battery can
(11) Tube
(12) Lid
(2) Winding electrode body
(3) Current collection tab
(4) Electrode terminal mechanism
(5) Terminal material
(6) Insulation cap member
(61) Cylindrical part
(62) Flat plate
(63) Tapered surface

Claims

筒体(11)の開口部に蓋体(12)を固定してなる電池缶(１)の内部に、巻き取り電極体(２)が収容され、蓋体(12)には、蓋体(12)に対して電気的絶縁と気密性を保って電極端子機構(４)が取り付けられ、巻き取り電極体(２)と電極端子機構(４)とが互いに電気的に接続されて、巻き取り電極体(２)が発生する電力を電極端子機構(４)から外部に取り出すことが可能な筒型電池において、電極端子機構(４)と接続された巻き取り電極体(２)の端部には、筒状の絶縁キャップ部材(６)が装着され、該絶縁キャップ部材(６)は、電池缶(１)の筒体(11)の内周面と巻き取り電極体(２)の外周面の間に緊密若しくは略緊密に嵌まる肉厚を有する筒部(61)を具え、巻き取り電極体 ( ２ ) の外周面には、巻き取り電極体 ( ２ ) の巻き軸方向の全長Ｌの５％以上の長さ範囲にて、絶縁キャップ部材 ( ６ ) の筒部 (61) の内周面が密着していることを特徴とする筒型電池。The winding electrode body (2) is accommodated in the battery can (1) formed by fixing the lid body (12) to the opening of the cylindrical body (11), and the lid body (12) includes a lid body (12). 12) The electrode terminal mechanism (4) is attached while maintaining electrical insulation and airtightness, and the take-up electrode body (2) and the electrode terminal mechanism (4) are electrically connected to each other for winding. In the cylindrical battery in which the electric power generated by the electrode body (2) can be taken out from the electrode terminal mechanism (4), the end of the winding electrode body (2) connected to the electrode terminal mechanism (4) Is provided with a cylindrical insulating cap member (6), and the insulating cap member (6) includes an inner peripheral surface of the cylindrical body (11) of the battery can (1) and an outer peripheral surface of the winding electrode body (2). A cylindrical portion (61) having a thickness that fits tightly or substantially tightly between the winding electrode body ( 2 ) and an outer circumferential surface of the winding electrode body ( 2 ) having a total length L in the winding axis direction of the winding electrode body ( 2 ) . Insulation key in the length range of 5% or more A cylindrical battery characterized in that the inner peripheral surface of the cylindrical portion (61) of the cap member ( 6 ) is in close contact .

絶縁キャップ部材(６)は、筒部(61)の端部に、電池缶(１)の蓋体(12)の内面に沿って拡がる平板部(62)を一体に具え、該平板部(62)が電極端子機構(４)によって挟持されている請求項１に記載の筒型電池。 The insulating cap member (6) integrally includes a flat plate portion (62) that extends along the inner surface of the lid (12) of the battery can (1) at the end of the cylindrical portion (61). The cylindrical battery according to claim 1, which is sandwiched by the electrode terminal mechanism (4).

絶縁キャップ部材(６)の材質は、ポリプロピレン、ポリエチレン、ポリテトラフルオロエチレンの何れかである請求項１又は請求項２に記載の筒型電池。 The cylindrical battery according to claim 1 or 2, wherein a material of the insulating cap member (6) is any one of polypropylene, polyethylene, and polytetrafluoroethylene.

絶縁キャップ部材(６)の筒部(61)の肉厚は、絶縁キャップ部材(６)を嵌める前の状態において電池缶(１)の筒体(11)の内周面と巻き取り電極体(２)の外周面との間に形成される隙間寸法の０.９倍以上、１.２倍以下に形成されている請求項１乃至請求項３の何れかに記載の筒型電池。 The thickness of the cylindrical portion (61) of the insulating cap member (6) is such that the inner peripheral surface of the cylindrical body (11) of the battery can (1) and the winding electrode body (in the state before the insulating cap member (6) is fitted) The cylindrical battery according to any one of claims 1 to 3, wherein the cylindrical battery is formed 0.9 times or more and 1.2 times or less the size of a gap formed between the outer peripheral surface of 2).

絶縁キャップ部材(６)の筒部(61)は、その内周面の先端部にテーパ面 (63) を有して、巻き取り電極体(２)に嵌合する端部の先端が鋭角に尖っている請求項１乃至請求項４の何れかに記載の筒型電池。The cylindrical portion (61) of the insulating cap member (6) has a tapered surface (63) at the distal end portion of the inner peripheral surface thereof, and the distal end of the end portion fitted to the winding electrode body (2) has an acute angle. The cylindrical battery according to any one of claims 1 to 4 , wherein the cylindrical battery is sharp.