JP3717684B2

JP3717684B2 - Cylindrical secondary battery

Info

Publication number: JP3717684B2
Application number: JP31073298A
Authority: JP
Inventors: 広一佐藤; 直哉中西; 秀行猪俣; 一恭藤原; 俊之能間; 育郎米津; 晃治西尾
Original assignee: Sanyo Electric Co Ltd
Current assignee: Sanyo Electric Co Ltd
Priority date: 1998-10-30
Filing date: 1998-10-30
Publication date: 2005-11-16
Anticipated expiration: 2018-10-30
Also published as: JP2000133221A

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二次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、エネルギー密度が高く、然もカドミウムや鉛の如き有害物質を含まないリチウム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３に示す様に、筒体(11)の両開口部にそれぞれ蓋体(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。各蓋体(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)と各電極端子機構(９)とがそれぞれ、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(９)(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)には安全弁(13)が取り付けられている。
【０００３】
巻き取り電極体(２)は、リチウム複合酸化物を含む正極(21)と炭素材料を含む負極(23)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(21)及び負極(23)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。
尚、図３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。
【０００４】
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)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。
【０００５】
【発明が解決しようとする課題】
しかしながら、上記従来の円筒型二次電池においては、金属製の電池缶(１)の内面がむき出しになっているため、特に電気自動車等の車両に搭載した場合、振動や衝撃が加わることによって、集電タブ(３)が電池缶(１)の内面、特に蓋体(12)の内面に接触して、集電タブ(３)と電池缶(１)とが短絡する虞れがあった。特に大型の円筒型二次電池においては、高容量、高出力化に伴って、集電タブ(３)の本数が増大するため、蓋体(12)との接触の可能性が高い。
【０００６】
そこで、蓋体(12)の内面に、塩化ビニル樹脂、アクリル樹脂、エポキシ樹脂などの樹脂塗料を塗布して、蓋体(12)の内面に絶縁膜を形成した二次電池が提案されている(特開平5-182647号［H01M2/02］)。
ところが、上述の樹脂塗料からなる絶縁膜は、電池缶(１)中の電解液に晒されることにより膨潤して軟化し、蓋体(12)内面から剥がれたり、集電タブ(３)の衝突によって破損する虞れがあった。
【０００７】
又、電池缶(１)の蓋体(12)と巻き取り電極体(２)の間に、蓋体(12)の内面全体を覆うことが可能な絶縁カバーを配備して、集電タブ(３)と蓋体(12)の間の短絡を防止した二次電池が知られているが、絶縁カバーの配置によって部品点数が増え、組立工数が増大してコストアップを招く問題がある。
【０００８】
そこで本発明の目的は、電池缶(１)の蓋体(12)と巻き取り電極体(２)の間に確実な電気的絶縁性が得られ、然も、組立工数が増大することのない構造の筒型二次電池を提供することである。
【０００９】
【課題を解決する為の手段】
本発明に係る筒型二次電池において、電極端子機構(４)は、電池缶(１)の蓋体(12)に開設された中央孔(18)を貫通して配置された端子部材(５)を具えている。該端子部材(５)には、蓋体(12)の外側へ突出するねじ軸部(53)と、蓋体(12)の内側に位置するフランジ部(51)とが形成され、端子部材(５)のねじ軸部(53)にはナット(８)が螺合し、端子部材(５)のフランジ部(51)に、巻取り電極体(２)から伸びる集電タブ(３)の先端部が連結されている。
又、蓋体(12)の中央孔(18)の内周面と端子部材(５)の外周面との間、並びに蓋体(12)の外面とナット(８)の背面との間は、絶縁部材によって電気的に絶縁されると共に、蓋体(12)の内面と端子部材(５)のフランジ部(51)の表面との間は、パッキン部材(６)によって電気的に絶縁されている。
該パッキン部材(６)は、蓋体(12)と端子部材(５)のフランジ部(51)によって挟圧されるボス部(61)と、該ボス部(62)の外周部に突設されて蓋体(12)の内面全体を覆う鍔部(62)とを具えている。
又、蓋体(12)とパッキン部材(６)の対向面間、並びに端子部材(５)のフランジ部(51)とパッキン部材(６)の対向面間には、それぞれシール部材が介在して、電池缶(１)の気密性が保たれている。
【００１０】
上記本発明の筒型二次電池においては、パッキン部材(６)の鍔部(62)が、蓋体(12)の内面全体を覆っているので、電池缶(１)に対して振動や衝撃が加わって、巻き取り電極体(２)が電池缶(１)内で移動したとしても、集電タブ(３)は、パッキン部材(６)の鍔部(62)によって受け止められ、蓋体(12)の内面に接触することはない。ここで、パッキン部材(６)を、ポリプロピレン、ポリエチレン、フッ素樹脂等から形成すれば、電解液中で膨潤することはない。従って、電池缶(１)の蓋体(12)と巻き取り電極体(２)との短絡が確実に防止される。
尚、パッキン部材(６)のボス部(61)は、従来の絶縁パッキン(93)の機能を発揮するものであって、該ボス部(61)と一体に鍔部(62)が形成されているので、従来の如く別体の絶縁カバーを配備した二次電池に比べて部品点数が減少し、組立工数も減少する。
【００１１】
具体的構成において、前記絶縁部材は、蓋体(12)の中央孔(18)の内周面と端子部材(５)の外周面との間に介在する絶縁パッキン(７)と、蓋体(12)の外面とナット(８)の背面との間に介在する絶縁リング(71)とから構成され、絶縁パッキン(７)は、ポリプロピレン、ポリエチレン、若しくはフッ素樹脂から形成され、絶縁リング(71)は、ポリテトラフルオロエチレン若しくはガラス繊維から形成されている。
該具体的構成によれば、絶縁リング(71)がポリテトラフルオロエチレン若しくはガラス繊維から形成されているので、従来の如くポリプロピレン製の絶縁パッキンを蓋体とナットの間に介在させた二次電池に比べて、ナット(８)の締め付け力を増大させることが可能であり、これによってシール性を高めることが出来る。
【００１２】
又、他の具体的構成において、蓋体(12)の中央孔(18)は断面多角形であって、端子部材(５)は、フランジ部(51)とねじ軸部(53)の間に、蓋体(12)の中央孔(18)に係合可能な角柱部(52)を具えている。
この場合、蓋体(12)の中央孔(18)の内周面と端子部材(５)の角柱部(52)との間に介在する絶縁パッキン(７)は角筒状に形成される。
該具体的構成によれば、蓋体(12)の中央孔(18)内における端子部材(５)の回転が阻止されるので、端子部材(５)のねじ軸部(53)に対してナット(８)をねじ込む過程で、端子部材(５)が伴回りすることはなく、ナット(８)の締め付けを容易に、然も大きなトルクで行なうことが出来る。
【００１３】
【発明の効果】
本発明に係る筒型二次電池によれば、電池缶(１)の蓋体(12)と巻き取り電極体(２)の間に確実な電気的絶縁性が得られ、然も、従来に比べて部品点数や組立工数が増大することはなく、低コストで製造、組立が可能である。
【００１４】
【発明の実施の形態】
以下、本発明の実施の形態につき、図面に沿って具体的に説明する。
本発明に係る円筒型二次電池は、図１に示す如く、筒体(11)の両開口部にそれぞれ蓋体(12)を溶接固定してなる円筒状のアルミニウム製電池缶(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。
尚、電池缶(１)の外径は６５ｍｍ、長さは３００ｍｍであって、蓋体(12)の厚さは３ｍｍに形成されている。又、電池容量は、７０Ａｈ(０.１２５Ｃ充電)である。
【００１５】
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１２本のアルミニウム製の集電タブが引き出されている。又、負極からは１２本のニッケル製の集電タブが引き出されている。
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１２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。
尚、集電タブ(３)は、厚さ０.１ｍｍに形成されている。
【００１６】
又、蓋体(12)には、図２に示す如く、電極端子機構(４)が貫通すべき断面四角形の中央孔(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)からなる爆裂型の安全弁(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、安全弁(14)は、蓋体(12)の圧力逃し孔(15)の開口縁にて溶接固定される。
【００１７】
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)に開設された断面四角形の中央孔(18)を貫通する断面四角形の角柱部(52)と、角柱部(52)に上向きに突設されたねじ軸部(53)と、角柱部(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。負極側の電極端子機構(４)も、端子部材(５)をニッケル製とする以外は同様にして作製する。
【００１８】
又、電極端子機構(４)は、蓋体(12)と端子部材(５)のフランジ部(51)との間に介在する円板状パッキン部材(６)を具えている。パッキン部材(６)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、若しくはフッ素樹脂を用いて一体成型され、蓋体(12)と端子部材(５)のフランジ部(51)によって挟圧されるボス部(61)と、該ボス部(62)の外周部に突設されて蓋体(12)の内面全体を覆うことが可能な鍔部(62)とから構成されている。
パッキン部材(６)のボス部(61)の中央部には、断面四角形の中央孔(64)が開設されている。又、鍔部(62)には、蓋体(12)の圧力逃し孔(15)と対応する位置に第１の貫通孔(65)が開設されると共に、蓋体(12)のねじ孔(17)に対応する位置に第２の貫通孔(66)が開設されている。
更に、パッキン部材(６)の蓋体(12)との対向面には、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。
尚、端子部材(５)のフランジ部(51)との対向面や、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。
【００１９】
蓋体(12)の中央孔(18)には、角筒状のポリプロピレン製絶縁パッキン(７)が装着される。
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、ポリテトラフルオロエチレン製の絶縁リング(71)及び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。
【００２０】
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)の先端部を電極端子機構(４)のフランジ部(51)の背面に溶接し、その後、蓋体(12)を筒体(11)の開口部に被せて、両者を互いに溶接固定する。
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に示す円筒型二次電池が完成する。
【００２１】
上記円筒型二次電池においては、絶縁パッキン(７)及び絶縁リング(71)によって、電池缶(１)の蓋体(12)と端子部材(５)の角柱部(52)及びねじ軸部(53)との間の電気的絶縁性が保たれると共に、パッキン部材(６)によって、電池缶(１)の蓋体(12)と端子部材(５)のフランジ部(51)との電気的絶縁性が保たれる。又、Ｏリング(72)(73)によって、電池缶(１)の蓋体(12)と端子部材(５)の間のシール性(気密性)が保たれる。
更に、電池缶(１)の蓋体(12)の内面全体がパッキン部材(６)によって覆われているので、電池缶(１)内で巻き取り電極体(２)が移動して、集電タブ(３)が弛んで蓋体(12)の内面へ接近したとしても、該集電タブ(３)はパッキン部材(６)の鍔部(62)により受け止められ、これによって電池缶(１)の蓋体(12)と集電タブ(３)との短絡が阻止される。
【００２２】
特に、上記実施例では、端子部材(５)の角柱部(52)が蓋体(12)の中央孔(18)に係合して、端子部材(５)の回転が阻止されるので、ナット(８)を従来よりも強い力で締め付けたとしても、端子部材(５)が伴回りすることはなく、これによって従来よりも高いシール性が得られる。この際、絶縁リング(71)としてポリテトラフルオロエチレン材が採用されているので、強い締め付け力によって絶縁リング(71)が破損する虞れはない。
【００２３】
上記本発明の円筒型二次電池のパッキン部材による効果を確認するべく、図１に示すパッキン部材(６)としてポリプロピレン材、ポリテトラフルオロエチレン材、及びポリエチレン材をそれぞれ採用した発明例Ａ１、Ａ２及びＡ３と、図３に示す従来の二次電池の蓋体(12)の内面に厚さ５μｍの塩化ビニル樹脂(塩化ビニル／酢酸ビニル共重合体)の絶縁膜を形成した従来例を、それぞれ１０個ずつ試作し、これらの電池に、振動数１００Ｈｚ、加速度３Ｇの振動を３０分間加えて、蓋体(12)と集電タブ(３)の間の短絡の有無を調べたところ、発明例においては何れも、短絡が発生しなかったのに対し、従来例では、１０個中の５個の電池で短絡が発生した。
短絡の発生した電池を解体して短絡の原因を調べたところ、蓋体(12)内面の塩化ビニル樹脂層が電解液によって膨潤して軟化しており、集電タブが塩化ビニル樹脂層を貫通して、蓋体の内面に接触していることを確認した。
【００２４】
又、上記本発明の円筒型二次電池の角柱部(52)を具えた端子部材(５)による効果を確認するべく、図１に示す二次電池においては、トルクレンチを用いてナット(８)を８０Ｋｇｆ・ｃｍのトルクで締め付けて、電池の組立を行なった。一方、図３に示す従来の二次電池においては、ナット(95)の締め付け力を徐々に増大させて、ねじ部材(91)が伴回りを開始する時点で締め付けを止め、電池の組立を行なった。尚、従来の二次電池におけるナットの最終的な締め付けトルクは４０Ｋｇｆ・ｃｍであった。この様な方法で組み立てた本発明電池Ａ−１、Ａ−２及びＡ−３と、従来電池Ｂ−１、Ｂ−２及びＢ−３のそれぞれにつき、窒素ガスを用いて電池缶内を１〜７Ｋｇ／ｃｍ²の範囲で徐々に加圧し、石鹸液によって各圧力におけるリークの有無を調べた。
【００２５】
この結果、本発明電池Ａ−１、Ａ−２及びＡ−３では何れの圧力でもリークが発生しなかったが、従来電池Ｂ−１では、４ｋｇ／ｃｍ²、従来Ｂ−２では５ｋｇ／ｃｍ²、従来電池Ｂ−３では４ｋｇ／ｃｍ²でリークが発生した。
これは、本発明電池では、ナットの締め付け力が大きく、十分な気密性が得られるに対し、従来電池ではナットの締め付け力が小さいために、十分な気密性が得られないことによるものである。
【００２６】
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、パッキン部材(６)と絶縁パッキン(７)は、一体に成型することも可能である。又、Ｏリング(72)(73)に代えて、シート状のシールパッキンを採用することも可能である。更に又、端子部材(５)の角柱部(52)及び蓋体(12)の中央孔(18)の断面形状は、四角形に限らず、六角形等、任意の多角形を採用することが出来る。
【図面の簡単な説明】
【図１】本発明に係る円筒型二次電池の要部を示す断面図である。
【図２】電極端子機構の分解斜視図である。
【図３】従来の円筒型二次電池の要部を示す断面図である。
【符号の説明】
(１) 電池缶
(11) 筒体
(12) 蓋体
(18) 中央孔
(14) 安全弁
(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
(51) フランジ部
(52) 角柱部
(53) ねじ軸部
(６) パッキン部材
(61) ボス部
(62) 鍔部
(７) 絶縁パッキン
(71) 絶縁リング
(８) ナット[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cylindrical secondary battery in which a winding electrode body is accommodated in a cylindrical battery can and power generated by the winding electrode body can be taken out from an electrode terminal mechanism attached to the battery can. Is.
[0002]
[Prior art]
In recent years, lithium secondary batteries that have high energy density and do not contain harmful substances such as cadmium and lead have attracted attention as power sources for portable electronic devices and electric vehicles.
For example, as shown in FIG. 3, a cylindrical lithium secondary battery having a relatively large capacity used in an electric vehicle has a cylindrical shape in which a lid (12) is fixed by welding to both openings of the cylindrical body (11). The winding electrode body (2) is accommodated in the battery can (1). An electrode terminal mechanism (9) is attached to each lid (12), and the take-up electrode body (2) and each electrode terminal mechanism (9) are each provided by a plurality of current collecting tabs (3). Connected to each other, the electric power generated by the winding electrode body (2) can be taken out from the pair of electrode terminal mechanisms (9) and (9). A safety valve (13) is attached to the lid (12).
[0003]
The take-up electrode body (2) includes a separator (22) impregnated with a non-aqueous electrolyte between a positive electrode (21) containing a lithium composite oxide and a negative electrode (23) containing a carbon material. Is wound in a spiral shape. A plurality of current collecting tabs (3) are drawn out from the positive electrode (21) and the negative electrode (23) 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).
Note that FIG. 3 shows a state in which the tip portions of some 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.
[0004]
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 flange portion (92) of the screw member (91) by spot welding or ultrasonic welding.
[0005]
[Problems to be solved by the invention]
However, in the conventional cylindrical secondary battery, since the inner surface of the metal battery can (1) is exposed, particularly when mounted on a vehicle such as an electric vehicle, vibration and impact are applied. There is a possibility that the current collecting tab (3) contacts the inner surface of the battery can (1), particularly the inner surface of the lid (12), and the current collecting tab (3) and the battery can (1) are short-circuited. In particular, in a large cylindrical secondary battery, the number of current collecting tabs (3) increases with an increase in capacity and output, so that the possibility of contact with the lid (12) is high.
[0006]
Therefore, a secondary battery has been proposed in which a resin paint such as vinyl chloride resin, acrylic resin, or epoxy resin is applied to the inner surface of the lid (12), and an insulating film is formed on the inner surface of the lid (12). (Japanese Patent Laid-Open No. 5-186447 [H01M2 / 02]).
However, the insulating film made of the above-mentioned resin paint swells and softens when exposed to the electrolyte in the battery can (1), peels off from the inner surface of the lid (12), or collides with the current collecting tab (3). There was a risk of damage.
[0007]
In addition, an insulating cover capable of covering the entire inner surface of the lid (12) is disposed between the lid (12) of the battery can (1) and the winding electrode body (2), and a current collecting tab ( A secondary battery that prevents a short circuit between 3) and the lid (12) is known, but there is a problem that the number of parts increases due to the arrangement of the insulating cover, and the number of assembly steps increases, resulting in an increase in cost.
[0008]
Therefore, an object of the present invention is to obtain a reliable electrical insulation between the lid (12) of the battery can (1) and the take-up electrode body (2) without increasing the number of assembly steps. It is to provide a cylindrical secondary battery having a structure.
[0009]
[Means for solving the problems]
In the cylindrical secondary battery according to the present invention, the electrode terminal mechanism (4) includes a terminal member (5) disposed through the central hole (18) formed in the lid (12) of the battery can (1). ). The terminal member (5) is formed with a screw shaft portion (53) protruding outward from the lid body (12) and a flange portion (51) located inside the lid body (12). The nut (8) is screwed into the screw shaft portion (53) of 5), and the tip of the current collecting tab (3) extending from the winding electrode body (2) to the flange portion (51) of the terminal member (5) The parts are connected.
Further, between the inner peripheral surface of the center hole (18) of the lid (12) and the outer peripheral surface of the terminal member (5), and between the outer surface of the lid (12) and the back surface of the nut (8), While being electrically insulated by the insulating member, the inner surface of the lid (12) and the surface of the flange portion (51) of the terminal member (5) are electrically insulated by the packing member (6). .
The packing member (6) protrudes from the boss part (61) clamped by the lid part (12) and the flange part (51) of the terminal member (5) and the outer peripheral part of the boss part (62). And a flange (62) covering the entire inner surface of the lid (12).
Seal members are interposed between the facing surfaces of the lid (12) and the packing member (6) and between the flange portion (51) of the terminal member (5) and the facing surface of the packing member (6). The airtightness of the battery can (1) is maintained.
[0010]
In the above-described cylindrical secondary battery of the present invention, the flange (62) of the packing member (6) covers the entire inner surface of the lid (12). Even if the take-up electrode body (2) is moved in the battery can (1) due to the added, the current collecting tab (3) is received by the flange portion (62) of the packing member (6) and the lid ( 12) There is no contact with the inner surface. Here, if the packing member (6) is made of polypropylene, polyethylene, fluororesin or the like, it will not swell in the electrolyte. Therefore, a short circuit between the lid (12) of the battery can (1) and the winding electrode body (2) is reliably prevented.
The boss portion (61) of the packing member (6) exhibits the function of the conventional insulating packing (93), and the flange portion (62) is formed integrally with the boss portion (61). As a result, the number of parts is reduced and the number of assembling steps is reduced as compared with a secondary battery in which a separate insulating cover is provided as in the prior art.
[0011]
In a specific configuration, the insulating member includes an insulating packing (7) interposed between the inner peripheral surface of the central hole (18) of the lid (12) and the outer peripheral surface of the terminal member (5), and a lid ( 12) is composed of an insulating ring (71) interposed between the outer surface of the nut and the back surface of the nut (8). The insulating packing (7) is made of polypropylene, polyethylene or fluororesin, and the insulating ring (71) Is formed from polytetrafluoroethylene or glass fiber.
According to this specific configuration, since the insulating ring (71) is formed of polytetrafluoroethylene or glass fiber, a secondary battery in which an insulating packing made of polypropylene is interposed between the lid and the nut as in the prior art. In comparison with the above, it is possible to increase the tightening force of the nut (8), thereby improving the sealing performance.
[0012]
In another specific configuration, the central hole (18) of the lid (12) has a polygonal cross section, and the terminal member (5) is disposed between the flange portion (51) and the screw shaft portion (53). And a prism portion (52) that can be engaged with the central hole (18) of the lid (12).
In this case, the insulating packing (7) interposed between the inner peripheral surface of the central hole (18) of the lid (12) and the prismatic part (52) of the terminal member (5) is formed in a rectangular tube shape.
According to the specific configuration, the rotation of the terminal member (5) in the central hole (18) of the lid (12) is prevented, so that the nut with respect to the screw shaft portion (53) of the terminal member (5). In the process of screwing (8), the terminal member (5) is not accompanied, and the nut (8) can be easily tightened with a large torque.
[0013]
【The invention's effect】
According to the cylindrical secondary battery of the present invention, reliable electrical insulation is obtained between the lid (12) of the battery can (1) and the winding electrode body (2). Compared to this, the number of parts and the number of assembly steps are not increased, and manufacturing and assembly can be performed at low cost.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
As shown in FIG. 1, a cylindrical secondary battery according to the present invention comprises a cylindrical aluminum battery can (1) formed by welding and fixing lids (12) to both openings of a cylindrical body (11). The winding electrode body (2) is accommodated inside.
The battery can (1) has an outer diameter of 65 mm, a length of 300 mm, and a lid (12) having a thickness of 3 mm. The battery capacity is 70 Ah (0.125 C charge).
[0015]
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 collector tab is pulled out. In addition, twelve nickel current collecting tabs are drawn from the negative electrode.
An electrode terminal mechanism (4) is attached to each lid body (12), and the winding electrode body (2) and each electrode terminal mechanism (4) are respectively connected to the twelve current collecting tabs (3). Thus, the electric power generated by the winding electrode body (2) can be taken out from the pair of electrode terminal mechanisms (4) and (4).
The current collecting tab (3) is formed with a thickness of 0.1 mm.
[0016]
Further, as shown in FIG. 2, the lid (12) is provided with a central hole (18) having a rectangular cross section through which the electrode terminal mechanism (4) can pass, and both sides of the central hole (18) are provided at the time of assembly. A screw hole (17) used for electrolyte injection, and a pressure relief hole (15) for mounting an explosion-type safety valve (14) composed of a ring member (14a) and a valve membrane (14b) are provided. In addition, after injection | pouring of electrolyte solution, a screw plug (16) is screwed in a screw hole (17). The safety valve (14) is fixed by welding at the opening edge of the pressure relief hole (15) of the lid (12).
[0017]
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 rectangular column part (52) having a quadrangular section passing through a central hole (18) having a quadrangular section formed in the lid (12), and a screw projecting upward from the square column part (52). The shaft portion (53) and a flange portion (51) formed at the lower end portion of the prismatic portion (52) are configured. A fluororesin O-ring (72) is fitted on the upper surface of the flange portion (51). A round ring groove (54) is recessed. The electrode terminal mechanism (4) on the negative electrode side is produced in the same manner except that the terminal member (5) is made of nickel.
[0018]
The electrode terminal mechanism (4) includes a disk-shaped packing member (6) interposed between the lid (12) and the flange portion (51) of the terminal member (5). The packing member (6) is integrally molded using polypropylene, polyethylene, polytetrafluoroethylene , or fluororesin, and is a boss portion that is clamped by the flange (51) of the lid (12) and the terminal member (5). (61) and a flange portion (62) that protrudes from the outer peripheral portion of the boss portion (62) and can cover the entire inner surface of the lid (12).
A central hole (64) having a square cross section is formed in the central portion of the boss portion (61) of the packing member (6). In addition, a first through hole (65) is opened in the collar portion (62) at a position corresponding to the pressure relief hole (15) of the lid body (12), and a screw hole ( A second through hole (66) is opened at a position corresponding to 17).
Further, a ring groove (67) into which a fluororesin O-ring (73) is fitted is formed in the surface of the packing member (6) facing the lid (12).
In addition, ring grooves (not shown) in which the O-rings (72) and (73) are fitted are recessed on the surface of the terminal member (5) facing the flange portion (51) and the inner surface of the lid (12). It is installed.
[0019]
A rectangular tube-shaped polypropylene insulating packing (7) is mounted in the central hole (18) of the lid (12).
An insulating ring (71) made of polytetrafluoroethylene and an aluminum washer (81) are fitted into the screw shaft (53) of the terminal member (5) protruding from the central hole (18) of the lid (12). Further, an aluminum nut (8) is screwed and tightened on the upper part.
[0020]
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 take-up electrode body (2) are welded to the back surface of the flange portion (51) of the electrode terminal mechanism (4). Thereafter, the lid (12) is placed over the opening of the cylindrical body (11), and both are welded and fixed together.
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 secondary battery shown in FIG. 1 is completed.
[0021]
In the cylindrical secondary battery, the lid (12) of the battery can (1), the prism (52) of the terminal member (5), and the screw shaft (by the insulating packing (7) and the insulating ring (71)). 53) and electrical insulation between the lid (12) of the battery can (1) and the flange (51) of the terminal member (5) by the packing member (6). Insulation is maintained. Further, the O-rings (72) and (73) maintain the sealing performance (airtightness) between the lid (12) of the battery can (1) and the terminal member (5).
Further, since the entire inner surface of the lid (12) of the battery can (1) is covered with the packing member (6), the winding electrode body (2) moves within the battery can (1), and the current collector is collected. Even if the tab (3) is loosened and approaches the inner surface of the lid (12), the current collecting tab (3) is received by the collar portion (62) of the packing member (6), thereby the battery can (1) The short circuit between the lid 12 and the current collecting tab 3 is prevented.
[0022]
In particular, in the above embodiment, since the prism portion (52) of the terminal member (5) engages with the central hole (18) of the lid (12) and the rotation of the terminal member (5) is prevented, the nut Even if (8) is tightened with a force stronger than before, the terminal member (5) is not accompanied, and thereby a higher sealing performance than in the past can be obtained. At this time, since the polytetrafluoroethylene material is adopted as the insulating ring (71), there is no possibility that the insulating ring (71) is damaged by a strong tightening force.
[0023]
In order to confirm the effect of the packing member of the cylindrical secondary battery of the present invention, Invention Examples A1 and A2 adopting a polypropylene material, a polytetrafluoroethylene material, and a polyethylene material as the packing member (6) shown in FIG. A3, and a conventional example in which an insulating film of vinyl chloride resin (vinyl chloride / vinyl acetate copolymer) having a thickness of 5 μm is formed on the inner surface of the lid (12) of the conventional secondary battery shown in FIG. Ten prototypes were manufactured, and vibrations of 100 Hz and acceleration of 3G were applied to these batteries for 30 minutes, and the presence or absence of a short circuit between the lid (12) and the current collecting tab (3) was examined. In all, no short circuit occurred, whereas in the conventional example, a short circuit occurred in 5 out of 10 batteries.
When the short-circuited battery was disassembled and the cause of the short circuit was investigated, the vinyl chloride resin layer on the inner surface of the lid (12) was swollen and softened by the electrolyte, and the current collecting tab penetrated the vinyl chloride resin layer. Then, it was confirmed that it was in contact with the inner surface of the lid.
[0024]
In order to confirm the effect of the terminal member (5) having the prism portion (52) of the cylindrical secondary battery of the present invention, the secondary battery shown in FIG. ) Was tightened with a torque of 80 kgf · cm to assemble the battery. On the other hand, in the conventional secondary battery shown in FIG. 3, the tightening force of the nut (95) is gradually increased, and the tightening is stopped when the screw member (91) starts rotating. It was. The final tightening torque of the nut in the conventional secondary battery was 40 kgf · cm. For each of the batteries A-1, A-2 and A-3 of the present invention assembled by such a method and the conventional batteries B-1, B-2 and B-3, the inside of the battery can is 1 using nitrogen gas. The pressure was gradually increased in the range of ˜7 Kg / cm ² and the presence or absence of leakage at each pressure was examined with a soap solution.
[0025]
As a result, the present invention batteries A-1, A-2 and A-3 did not leak at any pressure, but the conventional battery B-1 was 4 kg / cm ² and the conventional B-2 was 5 kg / cm. ^{2. In} conventional battery B-3, leakage occurred at 4 kg / cm ² .
This is because in the battery of the present invention, the nut tightening force is large and sufficient airtightness is obtained, whereas in the conventional battery, the nut tightening force is small, so that sufficient airtightness cannot be obtained. .
[0026]
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 packing member (6) and the insulating packing (7) can be integrally molded. Further, instead of the O-rings (72) and (73), a sheet-like seal packing can be adopted. Furthermore, the cross-sectional shape of the prism portion (52) of the terminal member (5) and the central hole (18) of the lid (12) is not limited to a quadrangle, and any polygon such as a hexagon can be adopted. .
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a main part of a cylindrical secondary battery according to the present invention.
FIG. 2 is an exploded perspective view of an electrode terminal mechanism.
FIG. 3 is a cross-sectional view showing a main part of a conventional cylindrical secondary battery.
[Explanation of symbols]
(1) Battery can
(11) Tube
(12) Lid
(18) Central hole
(14) Safety valve
(2) Winding electrode body
(3) Current collection tab
(4) Electrode terminal mechanism
(5) Terminal material
(51) Flange
(52) Square column
(53) Screw shaft
(6) Packing material
(61) Boss
(62) Buttocks
(7) Insulation packing
(71) Insulation ring
(8) Nut

Claims

The winding electrode body (2) is accommodated inside the battery can (1) formed by fixing the lid (12) to the opening of the cylindrical body (11), and the lid (12) of the battery can (1). The electrode terminal mechanism (4) is attached to the winding electrode body (2) and the electrode terminal mechanism (4) are connected to each other by the current collecting tab (3) to generate the winding electrode body (2). In the cylindrical secondary battery capable of taking out the electric power to be taken out from the electrode terminal mechanism (4), the electrode terminal mechanism (4) includes an inner surface of the lid (12) and a terminal member (5) facing the inner surface. A packing member (6) that electrically insulates the surface of the lid, and the packing member (6) includes a flange portion (62) covering the entire inner surface of the lid (12) on the outer periphery thereof. A cylindrical secondary battery characterized by comprising:

The winding electrode body (2) is accommodated inside the battery can (1) formed by fixing the lid (12) to the opening of the cylindrical body (11), and the lid (12) of the battery can (1). The electrode terminal mechanism (4) is attached to the winding electrode body (2) and the electrode terminal mechanism (4) are connected to each other by the current collecting tab (3) to generate the winding electrode body (2). In the cylindrical secondary battery in which the electric power to be taken out can be taken out from the electrode terminal mechanism (4), the electrode terminal mechanism (4) passes through the central hole (18) formed in the lid (12). The terminal member (5) is disposed, and the terminal member (5) includes a screw shaft portion (53) protruding outward from the lid (12) and a flange portion located inside the lid (12). (51) is formed, the nut (8) is screwed into the screw shaft portion (53) of the terminal member (5), and the winding electrode body (2) is fitted to the flange portion (51) of the terminal member (5). ) Is connected to the tip of the current collecting tab (3), and the inner periphery of the central hole (18) of the lid (12) And the outer peripheral surface of the terminal member (5) and between the outer surface of the lid (12) and the back surface of the nut (8) are electrically insulated by an insulating member, and the lid (12) The surface of the terminal member (5) facing the flange portion (51) is electrically insulated by the packing member (6), and the packing member (6) is disposed on the outer periphery of the inner surface of the lid (12). A cylindrical secondary battery comprising a collar (62) covering the whole.

A seal member is interposed between the facing surface of the lid (12) and the packing member (6) and between the flange portion (51) of the terminal member (5) and the facing surface of the packing member (6). The cylindrical secondary battery according to claim 2, wherein the airtightness of the can (1) is maintained.

The cylindrical secondary battery according to claim 2 or 3, wherein the packing member (6) is made of polypropylene, polyethylene, or fluororesin.

The insulating member includes an insulating packing (7) interposed between an inner peripheral surface of the central hole (18) of the lid (12) and an outer peripheral surface of the terminal member (5), and an outer surface of the lid (12). The insulating ring (71) is interposed between the back surface of the nut (8), the insulating packing (7) is made of polypropylene, polyethylene, or fluororesin, and the insulating ring (71) is made of polytetrafluoro The cylindrical secondary battery in any one of Claim 2 thru | or 4 formed from ethylene or glass fiber.

The central hole (18) of the lid body (12) has a polygonal cross section, and the terminal member (5) has a central hole of the lid body (12) between the flange portion (51) and the screw shaft portion (53). The cylindrical secondary battery according to any one of claims 2 to 5, further comprising a prism portion (52) engageable with (18).