JP3627359B2

JP3627359B2 - Sealed non-aqueous secondary battery

Info

Publication number: JP3627359B2
Application number: JP08514896A
Authority: JP
Inventors: 久鈴木
Original assignee: Ube Industries Ltd
Current assignee: Ube Corp
Priority date: 1996-04-08
Filing date: 1996-04-08
Publication date: 2005-03-09
Anticipated expiration: 2016-04-08
Also published as: JPH09274900A

Description

【０００１】
【発明の属する技術分野】
本発明は安全で耐久性のある電池に関し、特に落下等の衝撃が加わった時でも、電池内部を損傷させることなく性能を維持できる密閉型非水二次電池に関する。
【０００２】
【従来の技術】
近年、電子機器の高性能化、小型化、ポータブル化により、その電源として使用される電池に、従来のニッケルカドミウム電池や鉛蓄電池等に代わる高エネルギー密度の二次電池が要求されるようになっている。そこで、最近では負極に水素吸蔵合金を用いたニッケル水素電池や、軽金属を挿入放出可能な物質を正極及び負極に用いた非水二次電池の研究開発が行われ、一部の電子機器に使用されるようになった。特にリチウムの挿入放出を応用した密閉型非水二次電池は電池電圧が３．６Ｖと高く、高エネルギー密度を有するため、電池の小型軽量化が可能であり、また自己放電も少なくサイクル特性にも優れていることから、今後ポータブル機器用の電源として広く使用されることが期待されている。
従来のニッケルカドミウム電池やニッケル水素電池などの密閉型非水二次電池は誤って落下させても、ある程度の高さであれば、電解液の漏出や回路電圧、内部抵抗の変化が少なく、その性能が損なわれずに再使用できるように設計製作されている。しかしながら、リチウム二次電池は、その高エネルギー密度故に、圧力感応弁体や電流遮断体、正温度抵抗係数素子などの複雑な部品を封口部に組み込んでいるため、耐衝撃性に問題を残している。
本発明者はこれらの耐衝撃性について鋭意研究の結果、衝撃による電極群の移動による防爆弁体の破損や、ガスケットに嵌入された封口体の接触抵抗の増大に問題があることをつきとめ、本発明に至った。
【０００３】
【発明が解決しようとする課題】
本発明は、非水二次電池の安全性を確保した上で、衝撃を加えても、電解液の漏出や、電池抵抗の増大等をもたらさない構造の密閉型非水二次電池を提供しようとするものである。
【０００４】
【発明が解決しようとする課題】
発明の課題は、正負電極とセパレータを巻回してなる電極群と、上部絶縁板と非水電解液が有底電池外装缶内に収納され、絶縁性ガスケットに嵌入支持された封口体により該有底電池外装缶の開口部が閉塞されてなる密閉型非水二次電池において、該封口体が、排気孔付き正極端子キャップと、正温度抵抗係数素子（ＰＴＣ素子）と、電流遮断体と、防爆弁体とからなり、さらに該電流遮断体と該防爆弁体とが溶接されていることを特徴とする密閉型非水二次電池により解決された。
【０００５】
【発明の実施の形態】
以下に本発明の好ましい形態を説明するが、本発明はこれらに限定されるわけではない。
（１）正負電極とセパレータを巻回してなる電極群と、上部絶縁板と非水電解液が有底電池外装缶内に収納され、絶縁性ガスケットに嵌入支持された封口体により該有底電池外装缶の開口部が閉塞されてなる密閉型非水二次電池において、該封口体が、排気孔付き正極端子キャップと、正温度抵抗係数素子（ＰＴＣ素子）と、電流遮断体と、防爆弁体とからなり、さらに該電流遮断体と該防爆弁体とが溶接されていることを特徴とする密閉型非水二次電池。
（２）項１の封口体を構成する防爆弁体と電流遮断体に関し、該防爆弁体が電池内圧の上昇に伴って電極群側とは反対方向に変形し、該電流遮断体は、該防爆弁体と該ＰＴＣ素子との間に配置され、かつ該防爆弁体側に配置され貫通孔を有する第一導通体と、中央部に貫通孔を有する中間絶縁体と、該ＰＴＣ素子側に配置され貫通孔を有する第二導通体との３層の積層構造体であり、該第一導通体と該第二導通体は中央部で電気的に接続されていることを特徴とする密閉型非水二次電池。
（３）項２の防爆弁体と電流遮断体の第一導通体とが溶接されていることを特徴とする密閉型非水二次電池。
（４）該防爆弁体と該電流遮断体の第一導通体とがアルミニウム又はその合金からなることを特徴とする項１から３のいずれか１項に記載の密閉型非水二次電池。
（５）項１に記載の電極群と防爆弁体の間に配置される上部絶縁板は、防爆弁体の皿状体の周辺部に対向する部分で防爆弁体側に凸部が設けられ、かつ複数の孔を有することを特徴とする請求項１から４のいずれか１項に記載の密閉型非水二次電池。
（６）有底電池外装缶閉塞外周の凸部は、有底電池外装缶と絶縁性リングと該絶縁性リングの更に外側から電池の胴面及び端面の一部を覆う熱収縮チューブから構成され、該凸部と封口体を構成する端子キャップとの段差が、該有底電池外装缶閉塞外周の凸部の最も高い部分を基準として＋１．０から−０．５ｍｍであることを特徴とする請求項１から５のいずれか１項に記載の密閉型非水二次電池。
【０００６】
以下、本発明について詳述する。
衝撃には種種の場合があり得るが、本発明においては、机の上等からの落下による衝撃への耐性について説明するが、本発明は落下衝撃に限定されるわけではない。
本発明においては、電池の安全性向上のために、封口体を排気孔付き正極端子キャップと、正温度抵抗係数素子（ＰＴＣ素子）と、電流遮断体と、防爆弁体とからこうせいする。正温度抵抗係数素子は電池内温度が上昇すると抵抗が増大して電流を遮断する機能をもつ。電流遮断体は、第一導通体と中間絶縁体と第二導通体の積層構造体であり、第一導通体は防爆弁体側に配置され貫通孔を有し、第二導通体は正温度抵抗係数素子側すなわち正極端子キャップ側に配置され貫通孔を有する構造である。第一導通体と第二導通体とは中央部で電気的に接続され、該第一導通体の該接続部の周囲に肉薄部を有している。防爆弁体は、内圧上昇時に電極群側とは反対側へ変形できるもので、上記した電流遮断体の第一導通体中央接続部を押し上げることができるものであれば良いが、特に外周部近傍から電極群側へ突出する突出平坦部を有する皿状体で、突出平坦部の中央部に、内圧上昇時に電流遮断体の第一導通体中央接続部に作用し得る作用体を有するものが好ましく、さらに、上記突出平坦部の中央部に電流遮断体側へ突出する突起部を一体的に有する特願平６−２９４６１１に記載の防爆弁体であることが好ましい。この防爆弁体と電流遮断体は、電池内の異常反応により、内圧が上昇すると変形した弁体が電流遮断体の第一導通体と第二導通体の接続部分を破断して電流を遮断し、さらに圧力が増大すると弁体の薄肉部が破壊して圧力を放出する。この時電流遮断体を防爆弁体の電極群側とは反対側に配置しているので、遮断部において、電解液蒸気への引火を原因とする電池の破裂が防止される。
【０００７】
上記の安全機構を内蔵させた電池においても、落下等の衝撃で電極群が防爆弁体を押し変形させ、電流遮断体を誤動作させたり、防爆弁体を損傷させ漏液を生じ、使用不可能になってしまう場合があった。その対策として防爆弁体保護フレームを弁体に付属させたり、封口体に組み込んだりしていたが、封口体のカシメ強度が低下したり、組立工程適性に難があった。
本発明は、電極群と防爆弁体の間に、電極群と外装缶又は封口体体との絶縁を兼ねる板状の上部絶縁板を配置し、該上部絶縁板の外周近傍には防爆弁体側に凸部が設けられていて、この凸部は防爆弁体の皿状体の周縁部に対向している。この凸部先端と防爆弁体の皿状体とは接触していてもよい。接触していない場合に凸部先端と皿状体の間隔は１ｍｍ以下が好ましい。本発明の上部絶縁板は２個以上、好ましくは３個以上の孔を有している。孔の中の少なくとも１つは直径が２ｍｍ以上、好ましくは４ｍｍ以上である。
凸部を有する本発明の絶縁板は、絶縁板の中央部が電極群に押し上げられて防爆弁体の皿状体の中央部を変形させて電流遮断体を誤動作させたり、防爆弁体を損傷させて漏液させてしまうということを解決することが可能となる。該上部絶縁板は樹脂を射出成形して作るのが一般的であるが、その際、金属製のリング状の部品等を絶縁が保てるようにインサートして成形し該上部絶縁板自体の剛性を上げると効果的である。インサートする金属はステンレス鋼など耐腐食の高いものが適している。
【０００８】
本発明の電池は上記の種種の部品による安全機構を封口部に内蔵させたものであるため、各部品間の導通の確保が重要である。通常、数種の封口部品を絶縁性ガスケット内に積層させて、これらの封口部品をガスケットを介し電池外装缶でかしめ閉塞させる方法が一般的である。これらの封口体では、部品同志の接触抵抗が変化したり、高くなったりしないように、元々導電性の悪い酸化皮膜を形成するアルミニウム同志の接触を避ける構成をとっている。アルミニウムまたはその合金を使用する場合、それと接する部品にはニッケル又は表面にニッケルメッキ等を施した導電性の良い材料を使用し、部品同志の接触抵抗の低減安定化を図るのが通常である。
【０００９】
本発明は、積層構造の封口体でアルミニウムまたはその合金製封口部品同志が接触して導通する部分を溶接により接続することで、落下等の外部からの衝撃が加わっても封口部品間の抵抗を安定して小さくするとともに、アルミニウム又はその合金の使用により安全機構の作動をより確実にしたものである。溶接する防爆弁体と電流遮断体の第一導通体には、ＪＩＳ規格１０００番系アルミニウムを用いた。溶接手段としては、レーザ溶接又は超音波溶着がこのましい。
レーザ溶接の好ましい条件は次の通りである。電圧２５０Ｖ〜２９０Ｖ、パルス幅１ｍｓｅｃ〜３ｍｓｅｃの条件で可能で、さらに電圧２６０Ｖ〜２８０Ｖ、パルス幅１．５ｍｓｅｃ〜２ｍｓｅｃの条件でより良好な溶接強度と電気的な導通が得られた。
超音波溶着の好ましい条件は次の通りである。溶着は防爆弁体側からホーンを押付け、電流遮断体側をアンビルで受け行った。溶着はホーン押付け力３０Ｎ〜５０Ｎ、振幅８μｍ〜１２μｍ、エネルギ５Ｊ〜２５Ｊ、周波数４０ＫＨｚの条件で可能で、さらにホーン押付け力４０Ｎ〜５０Ｎ、振幅８μｍ〜１０μｍ、エネルギ１５Ｊ〜２５Ｊ、周波数４０ＫＨｚの条件でより良好な溶着強度と電気的な導通が得られた。
【００１０】
衝撃による電池性能の劣化の原因には、上記の他に負極端子キャップの変形とそれに伴う封口体の変形がある。本発明では、これらの変形を外装缶閉塞外周の凸部と端子キャップの段差を、外装缶閉塞外周の凸部を基準（電池を立てた場合に最も高い位置）として＋１．０ｍｍから−０．５ｍｍとすることで改良した。段差は＋０．５ｍｍから−０．３ｍｍがより好ましく、＋０．１５ｍｍから０ｍｍが特に好ましい。ここで、＋は端子キャップが飛び出した状態を、−は引っ込んだ状態を指す。落下時の封口体の電極群側への中央部凸湾曲を段差以下にし、電流遮断体自体の抵抗増加、電流遮断体の誤動作をなくすことが可能になる。段差を＋１．０ｍｍ以上にすると落下時電流遮断体自体の抵抗増加が多くなり、時には電流遮断体が誤動作する。段差が−０．５ｍｍを越えると外部端子との接続性が劣る。段差は絶縁のため該外装缶閉塞外周の凸部上に載置する絶縁性リングの厚みと、該絶縁性リングの更に外側から電池の胴面及び端面の一部を覆う熱収縮チューブの厚さで調整することも可能である。外装缶閉塞外周の凸部が端子キャップより高くなると、該端子キャップへのリード溶接が困難になるため、該端子キャップは外装缶閉塞外周の凸部より高い方が望ましい。絶縁性リングは、紙やプラスチックが好ましく、プラスチックの中ではポリプロピレンが好ましい。
【００１１】
本発明の非水二次電池に用いられる正・負極は、正極合剤あるいは負極合剤を集電体上に塗設、あるいはペレット状に成形して作ることができる。正極あるいは負極合剤には、それぞれ正極活物質あるいは負極材料の他、それぞれに導電剤、結着剤、分散剤、フィラー、イオン導電剤、圧力増強剤や各種添加剤を含むことができる。
【００１２】
本発明で使用できる正極中の活物質は、軽金属を挿入放出できるものであれば良いが、好ましくはリチウム含有遷移金属酸化物であり、さらに好ましくはＬｉ_ｘＣｏＯ_２、Ｌｉ_ｘＮｉＯ_２、Ｌｉ_ｘＣｏ_ａＮｉ_１−ａＯ_２、Ｌｉ_ｘＣｏ_ｂＶ_１−ｂＯ_ｚ、Ｌｉ_ｘＣｏ_ｂＦｅ_１ーｂＯ_ｚ、Ｌｉ_ｘＭｎ_２Ｏ_４、Ｌｉ_ｘＭｎＯ_２、ＬｉＭｎ_２Ｏ_３、Ｌｉ_ｘＭｎ_ｂＣｏ_２ーｂＯ_ｚ、Ｌｉ_ｘＭｎ_ｂＮｉ_２ーｂＯ_ｚ、Ｌｉ_ｘＭｎ_ｂＶ_２ーｂＯ_ｚ、Ｌｉ_ｘＭｎ_ｂＦｅ_１ーｂＯ_ｚ（ここでｘ＝０．０５〜１．２、ａ＝０．１〜０．９、ｂ＝０．８〜０．９８、ｚ＝１．５〜５）である。
以下、本発明で言う軽金属とは、周期律表第１Ａ族（水素を除く）及び第２Ａ族に属する元素であり、好ましくはリチウム、ナトリウム、カリウムであり、特にリチウムであることが好ましい。
【００１３】
本発明で使用できる負極中の活物質は、軽金属を挿入放出できるものであれば良いが、好ましくは黒鉛（天然黒鉛、人造黒鉛、気相成長黒鉛）、コークス（石炭または石油系）、有機ポリマー焼成物（ポリアクリロニトリルの樹脂または繊維、フラン樹脂、クレゾール樹脂、フェノール樹脂）、メゾフェースピッチ焼成物、金属酸化物、金属カルコゲナイド、リチウム含有遷移金属酸化物及びカルコゲナイドである。
特に，Ｇｅ，Ｓｎ，Ｐｂ，Ｂｉ，Ａｌ，Ｇａ，Ｓｉ、Ｓｂの単独あるいはこれらの組み合わせからなる酸化物、カルコゲナイドが好ましい。更に、これらに網目形成剤として知られているＳｉＯ_２、Ｂ_２Ｏ_３、Ｐ_２Ｏ_５、Ａｌ_２Ｏ_３、Ｖ_２Ｏ_５などを加えて非晶質化させたものが特に好ましい。これらは化学量論組成のものであっても、不定比化合物であっても良い。
これらの化合物の好ましい例として以下のものを上げることができるが本発明はこれらに限定されるものではない。
【００１４】
ＧｅＯ、ＧｅＯ_２、ＳｎＯ、ＳｎＯ_２、ＳｎＳｉＯ_３、ＰｂＯ、ＳｉＯ、Ｓｂ_２Ｏ_５、Ｂｉ_２Ｏ_３、Ｌｉ_２ＳｉＯ_３、Ｌｉ_４Ｓｉ_２Ｏ_７、Ｌｉ_２ＧｅＯ_３、ＳｎＡｌ_０．４Ｂ_０．５Ｐ_０．５Ｋ_０．１Ｏ_３．６５、ＳｎＡｌ_０．４Ｂ_０．５Ｐ_０．５Ｃｓ_０．１Ｏ_３．６５、ＳｎＡｌ_０．４Ｂ_０．５Ｐ_０．５Ｋ_０．１Ｇｅ_０．０５Ｏ_３．８５、ＳｎＡｌ_０．４Ｂ_０．５Ｐ_０．５Ｋ_０．１Ｍｇ_０．１Ｇｅ_０．０２Ｏ_３．８３、ＳｎＡｌ_０．４Ｂ_０．４Ｐ_０．４Ｂａ_０．０８Ｏ_３．２８、ＳｎＡｌ_０．５Ｂ_０．４Ｐ_０．５Ｍｇ_０．１Ｆ_０．２Ｏ_３．６５、ＳｎＡｌ_０．４Ｂ_０．５Ｐ_０．５Ｃｓ_０．１Ｍｇ_０．１Ｆ_０．２Ｏ_３．６５、ＳｎＢ_０．５Ｐ_０．５Ｃｓ_０．０５Ｍｇ_０．０５Ｆ_０．１Ｏ_３．０３、Ｓｎ_１．１Ａｌ_０．４Ｂ_０．４Ｐ_０．４Ｂａ_０．０８Ｏ_３．３４、Ｓｎ_１．２Ａｌ_０．５Ｂ_０．３Ｐ_０．４Ｃｓ_０．２Ｏ_３．５、ＳｎＳｉ_０．５Ａｌ_０．２Ｂ_０．１Ｐ_０．１Ｍｇ_０．１Ｏ_２．８、ＳｎＳｉ_０．５Ａｌ_０．３Ｂ_０．４Ｐ_０．５Ｏ_４．３０、ＳｎＳｉ_０．６Ａｌ_０．１Ｂ_０．１Ｐ_０．１Ｂａ_０．２Ｏ_２．９５、ＳｎＳｉ_０．６Ａｌ_０．４Ｂ_０．２Ｍｇ_０．１Ｏ_３．２、Ｓｎ_０．９Ｍｎ_０．３Ｂ_０．４Ｐ_０．４Ｃａ_０．１Ｒｂ_０．１Ｏ_２．９５、Ｓｎ_０．９Ｆｅ_０．３Ｂ_０．４Ｐ_０．４Ｃａ_０．１Ｒｂ_０．１Ｏ_２．９５、Ｓｎ_０．３Ｇｅ_０．７Ｂａ_０．１Ｐ_０．９Ｏ_３．３５、Ｓｎ_０．９Ｍｎ_０．１Ｍｇ_０．１Ｐ_０．９Ｏ_３．３５、Ｓｎ_０．２Ｍｎ_０．８Ｍｇ_０．１Ｐ_０．９Ｏ_３．３５。
【００１５】
さらに本発明の負極材料は、軽金属、特にリチウムを挿入して用いることができる。リチウムの挿入方法は、電気化学的、化学的、熱的方法が好ましい。
【００１６】
本発明の負極材料へのリチウム挿入量は、リチウムの析出電位に近似するまででよいが、上記の好ましい負極材料当たり５０〜７００モル％が好ましい。特に１００〜６００モル％が好ましい。
【００１７】
本発明で使用できる正極及び負極中の導電剤は、グラファイト、アセチレンブラック、カーボンブラック、ケッチェンブラック、炭素繊維や金属粉、金属繊維やポリフェニレン誘導体であり、特にグラファイト、アセチレンブラックが好ましい。
本発明で使用できる正極及び負極中の結着剤は、ポリアクリル酸、カルボキシメチルセルロース、ポリテトラフルオロエチレン、ポリフッ化ビニリデン、ポリビニルアルコール、澱粉、再生セルロース、ジアセチルセルロース、ヒドロキシプロピルセルロース、ポリビニルクロリド、ポリビニルピロリドン、ポリエチレン、ポリプロピレン、ＳＢＲ，ＥＰＤＭ、スルホン化ＥＰＤＭ、フッ素ゴム、ポリブタジエン、ポリエチレンオキシドであり、特にポリアクリル酸、カルボキシメチルセルロース、ポリテトラフルオロエチレン、ポリフッ化ビニリデンが好ましい。
【００１８】
本発明で使用できる正極及び負極の支持体即ち集電体は、材質として、正極にはアルミニウム、ステンレス鋼、ニッケル、チタン、またはこれらの合金であり、負極には銅、ステンレス鋼、ニッケル、チタン、またはこれらの合金であり、形態としては、箔、エキスパンドメタル、パンチングメタル、金網である。特に、正極にはアルミニウム箔、負極には銅箔が好ましい。
本発明で使用できるセパレータは、イオン透過度が大きく、所定の機械的強度を持ち、絶縁性の薄膜であれば良く、材質として、オレフィン系ポリマー、フッ素系ポリマー、セルロース系ポリマー、ポリイミド、ナイロン、ガラス繊維、アルミナ繊維が用いられ、形態として、不織布、織布、微孔性フィルムが用いられる。特に、材質として、ポリプロピレン、ポリエチレン、ポリプロピレンとポリエチレンの混合体、ポリプロピレンとテフロンの混合体、ポリエチレンとテフロンの混合体が好ましく、形態として微孔性フィルムであるものが好ましい。特に、孔径が０．０１〜１μｍ、厚みが５〜５０μｍの微孔性フィルムが好ましい。
【００１９】
本発明で使用できる電解液は、有機溶媒としてプロピレンカーボネート、エチレンカーボネート、ブチレンカーボネート、ジメチルカーボネート、ジエチルカーボネート、１，２−ジメトキシエタン、γ−ブチロラクトン、テトラヒドロフラン、２−メチルテトラヒドロフラン、ジメチルスフォキシド、ジオキソラン、１，３−ジオキソラン、ホルムアミド、ジメチルホルムアミド、ニトロメタン、アセトニトリル、蟻酸メチル、酢酸メチル、プロピオン酸メチル、燐酸トリエステル、トリメトキシメタン、ジオキソラン誘導体、スルホラン、３−メチル−２−オキサゾリジノン、プロピレンカーボネート誘導体、テトラヒドロ誘導体、ジエチルエーテル、１，３−プロパンサルトンの少なくとも１種以上を混合したもの、また電解質として、ＬｉＣｌＯ_４、ＬｉＢＦ_４、ＬｉＰＦ_６、ＬｉＣＦ_３ＳＯ_３、ＬｉＣＦ_３ＣＯ_２、ＬｉＡｓＦ_６、ＬｉＳｂＦ_６、ＬｉＢ_１０Ｃｌ_１０、低級脂肪族カルボン酸リチウム、ＬｉＡｌＣｌ_４、ＬｉＣｌ、ＬｉＢｒ、ＬｉＩ、クロロボランリチウム、四フェニルホウ酸リチウムの１種以上の塩を溶解したものが好ましい。特にプロピレンカーボネートあるいはエチレンカーボネートと１、２−ジメトキシエタン及び／あるいはジエチルカーボネートとの混合溶媒にＬｉＣＦ_３ＳＯ_３、ＬｉＣｌＯ_４、ＬｉＢＦ_４、及び／あるいはＬｉＰＦ_６を溶解したものが好ましく、特に、少なくともエチレンカーボネートとＬｉＰＦ_６を含むことが好ましい。
【００２０】
電池の形状はボタン、コイン、シート、シリンダー、角などのいずれにも適用できる。ボタン、コインでは、合剤をペレット状にプレス成形して用い、シート、角、シリンダーでは合剤を集電体上に塗設、乾燥、脱水、プレスして用いる。電池は、ペレット、シート状あるいはセパレーターと共に巻回した電極を電池缶に挿入し、缶と電極を電気的に接続し、電解液を注入し封口して形成する。電池には、誤動作時にも安全を確保できる手段として電流遮断機構及び内圧開放防爆弁体を備えることが好ましい。
【００２１】
本発明で使用できる有底電池外装缶は、材質として、ニッケルメッキを施した鉄鋼板、ステンレス鋼板（ＳＵＳ３０４、ＳＵＳ３０４Ｌ，ＳＵＳ３０４Ｎ、ＳＵＳ３１６、ＳＵＳ３１６Ｌ、ＳＵＳ４３０、ＳＵＳ４４４等）、ニッケルメッキを施したステンレス鋼板（同上）、アルミニウムまたはその合金、ニッケル、チタン、銅であり、形状として、真円形筒状、楕円形筒状、正方形筒状、長方形筒状である。特に、外装缶が負極端子を兼ねる場合は、ステンレス鋼板、ニッケルメッキを施した鉄鋼板が好ましく、外装缶が正極端子を兼ねる場合は、ステンレス鋼板、アルミニウムまたはその合金が好ましい。
【００２２】
本発明で使用できるガスケットは、材質として、オレフィン系ポリマー、フッ素系ポリマー、セルロース系ポリマー、ポリイミド、ポリアミドであり、耐有機溶媒性及び低水分透過性から、オレフィン系ポリマーが好ましく、特にプロピレン主体のポリマーが好ましい。さらに、プロピレンとエチレンのブロック共重合ポリマーであることが好ましい。
【００２３】
本発明の電池は必要に応じて外装材で被覆される。外装材としては、熱収縮チューブ、粘着テープ、金属フィルム、紙、布、塗料、プラスチックケース等がある。また、外装の少なくとも一部に熱で変色する部分を設け、使用中の熱履歴がわかるようにしても良い。
本発明の電池は必要に応じて複数本を直列及び／または並列に組み電池パックに収納される。電池パックには正温度係数抵抗体、温度ヒューズ、ヒューズ及び／または電流遮断素子等の安全素子の他、安全回路（各電池及び／または組電池全体の電圧、温度、電流等をモニターし、必要なら電流を遮断する機能を有す回路）を設けても良い。また電池パックには、組電池全体の正極及び負極端子以外に、各電池の正極及び負極端子、組電池全体及び各電池の温度検出端子、組電池全体の電流検出端子等を外部端子として設けることもできる。また電池パックには、電圧変換回路（ＤＣ−ＤＣコンバータ等）を内蔵しても良い。また各電池の接続は、リード板を溶接することで固定しても良いし、ソケット等で容易に着脱できるように固定しても良い。さらには、電池パックに電池残存容量、充電の有無、使用回数等の表示機能を設けても良い。
【００２４】
本発明の電池は様々な機器に使用される。特に、ビデオムービー、モニター内蔵携帯型ビデオデッキ、モニター内蔵ムービーカメラ、コンパクトカメラ、一眼レフカメラ、使い捨てカメラ、レンズ付きフィルム、ノート型パソコン、ノート型ワープロ、電子手帳、携帯電話、コードレス電話、ヒゲソリ、電動工具、電動ミキサー、自動車等に使用されることが好ましい。
【００２５】
【実施例】
以下に具体例をあげ、本発明をさらに詳しく説明するが、発明の主旨を越えない限り、本発明は実施例に限定されるものではない。
はじめに電極の作り方を説明し、次に電池の組み立てかたを説明する。
負極活物質としてＳｎＢ_０．２Ｐ_０．５Ｋ_０．１Ｍｇ_０．１Ｇｅ_０．１Ｏ_２．８を８６重量部、導電剤としてアセチレンブラック３重量部とグラファイト６重量部の割合で混合し、さらに結着剤として０．２μの水性分散物であるポリ弗化ビニリデンを４重量部及びカルボキシメチルセルロース１重量部を加え、水を媒体として混練してスラリーを得た。該スラリーを厚さ１０μｍの銅箔の両面にエクストルージョン式塗布機を使って塗設し、乾燥後カレンダープレス機により圧縮成形して帯状の負極を作成した。
正極活物質としてＬｉＣｏＯ２を８７重量部、導電剤としてアセチレンブラック３重量部とグラファイト６重量部の割合で混合し、さらに結着剤としてＮｉｐｏｌ８２０Ｂ（日本ゼオン製）３重量部とカルボキシメチルセルロース１重量部を加え、水を媒体として混練してスラリーを得た。該スラリーを厚さ２０μｍのアルミニウム箔の両面にエクストルージョン式塗布機を使って塗設し、乾燥後カレンダープレス機により圧縮成形して帯状の正極を作成した。
【００２６】
上記負極及び正極のそれぞれも端部にニッケル及びアルミニウム製のリード板をそれぞれ溶接した後、露点−４０℃以下の乾燥空気中で２３０℃で１時間熱処理した。熱処理は遠赤外線ヒーターを用いて行った。さらに、熱処理済みの正極、微多孔性ポリエチレン／ポリプロピレンフィルム製セパレータ、熱処理済みの負極及びセパレータの順で積層し、これを渦巻状に巻回した。
この巻回体を負極端子を兼ねる、ニッケルめっきを施した鉄製の有底円筒型電池缶に収納した。さらに、電解質として１ｍｏｌ／リットルＬｉＰＦ_６（エチレンカーボネートとジエチルカーボネートの２対８重量比混合液）を電池缶内に注入した。正極端子を有する電池蓋をガスケットを介してかしめて円筒型電池を作成した。なお、正極端子は正極と、電池缶は負極と予めリード端子により接続した。
【００２７】
比較電池
本発明の効果を確認するため本発明を盛り込まない比較用密閉型非水二次電池を下記の手順で製作した。以下図１を用いて説明する。比較電池は正極（２ａ）と負極（２ｂ）とをセパレータ（２ｃ）を介して巻回し、ポリプロピレン基材のアクリル系接着剤テープで巻き止めた電極群を、その上下に０．３ｍｍの厚さのポリプロピレン製の孔を有する平板状の絶縁体（３ａ）を配置した状態で非水電解液と共に外形約１６．５ｍｍの外装缶（１）に収納し、さらに外装缶開口部にアスファルトを塗布した絶縁性ガスケットを介して複数の封口部品からなる封口体を配置し外装缶を内側にかしめ閉塞密閉して製作した。かしめ後の電池の総高は約６７０ｍｍとなるようにした。封口部外側の短絡防止のため、外装缶閉塞外周の凸部上には絶縁のためのポリプロピレン製のリング（１０）を載置し、さらに外側から電池の胴面および端面の一部を架橋性ポリエチレンの熱収縮チューブ（１１）で覆った。この時の外装缶閉塞外周の凸部上に載置する絶縁性リングと該絶縁性リングのさらに外側から電池の胴面および端面の一部を覆う熱収縮チューブの厚さを含めた端子キャップとの段差（図７の１５）は＋１．２ｍｍとした。
【００２８】
電池Ａ
電池Ａは本発明の防爆弁体と電流遮断体の電気的な接続を確実にして製作した電池の実施例である。図２に示すように、防爆弁体（６）と電流遮断体（７）を重ね合わせた後一定の力で押さえながら、共にＪＩＳ規格１０００番系アルミニウム製の防爆弁体と電流遮断体の第一導通体（７ａ）の外周部をＹＡＧレーザ溶接機で２点点溶接した。本実施の溶接は特に良好な溶接強度と電気的な導通が得られた電圧２８０Ｖ、パルス幅１．５ｍｓｅｃの条件で行った。溶接を行った防爆弁体と電流遮断体を組み込むこと以外は、比較電池と同様の手順で電池を製作した。
【００２９】
電池Ａ’
電池Ａ’は本発明の防爆弁体と電流遮断体の電気的な接続を確実にして製作した電池の別の実施例である。図３に示すように、防爆弁体と電流遮断体を重ね合わせた後、共にＪＩＳ規格１０００番系アルミニウム製の防爆弁体と電流遮断体の第一導通体の外周部近傍を２点超音波溶着した。本実施の溶着は特に良好な溶着強度と電気的な導通が得られたホーン押付け力４０Ｎ、振幅９μｍ、エネルギ１５Ｊ、周波数４０ＫＨｚの条件で行った。溶着を行った防爆弁体と電流遮断体を組み込むこと以外は、比較電池と同様の手順で電池を製作した。
【００３０】
電池Ｂ
電池Ｂは本発明の外周部近傍に凸部を有する上部絶縁板を組み込んで製作した電池の実施例である。図４は本実施例で使用した上部絶縁板を示し、図５は該上部絶縁板を電池に組込んだ図である。本実施例の上部絶縁板（３ｂ）の形状は外形が１５ｍｍで、凸部は外周から１．５ｍｍ〜２．５ｍｍのところに幅１ｍｍであり、その高さは上部絶縁板底面から１．５ｍｍで、対向する防爆弁体との距離は凸部で０ｍｍ〜０．５ｍｍである。図４の上部絶縁板はポリプロピレンを射出成形して製作した。図４の上部絶縁板を組み込むこと以外は、比較電池と同様の手順で電池を製作した。
【００３１】
電池Ｂ’
電池Ｂ’は本発明の外周部近傍に凸部を有する上部絶縁板を組み込んで製作した電池の別の実施例である。図６は本実施例で使用した上部絶縁板で、上部絶縁板の剛性を上げるため上部絶縁板内部に電極群と対向する面の絶縁性が損なわれないようにＳＵＳ３１６Ｌ製の外形１１ｍｍ、内径５ｍｍ、厚さ０．３ｍｍのリングをインサートして射出成形したものである。金属製リングをインサートすること以外は電池Ｂの上部絶縁板と同じ形状で製作した。図６の上部絶縁板を組み込むこと以外は、比較電池と同様の手順で電池を製作した。
【００３２】
電池Ｃ
電池Ｃは本発明の外装缶閉塞外周の凸部と端子キャップの段差の関係を採用した電池の実施例である。図７は本実施例の該段差の関係を示すものである。外装缶閉塞外周凸部上に載置する絶縁リングはポリプロピレン製で外形１５ｍｍ、内径９ｍｍ、厚さ０．５ｍｍである。該絶縁リングの更に外側から電池の胴面及び端面の一部を覆う熱収縮チューブは架橋性ポリエチレン製で熱収縮後の厚さは０．１５ｍｍである。絶縁リングと熱収縮チューブ装着後の外装缶閉塞外周の凸部と端子キャップの段差は＋０．０８ｍｍで端子キャップが外に出ている。図７の段差となるようにしたこと以外は、比較電池と同様の手順で電池を製作した。
【００３３】
電池ＢＣ
電池ＢＣは電池Ｂの上部絶縁板と電池Ｃの外装缶閉塞外周の凸部と端子キャップの段差の関係を採用した電池の実施例である。電池Ｂの上部絶縁板を組み込み、かつ電池Ｃの段差となるようにしたこと以外は、比較電池と同様の手順で電池を製作した。
【００３４】
電池ＡＢＣ
電池ＡＢＣは電池Ａのレーザ溶接を行った防爆弁体と電流遮断体を組み込み、電池Ｂの上部絶縁板と電池Ｃの外装缶閉塞外周の凸部と端子キャップの段差の関係を採用した電池の実施例である。電池Ａの防爆弁体と電流遮断体と電池Ｂの上部絶縁板を組み込み、かつ電池Ｃの段差となるようにしたこと以外は、比較電池と同様の手順で電池を製作した。
【００３５】
上記実施例の電池Ａ、電池Ａ’、電池Ｂ、電池Ｂ’、電池Ｃ、電池ＢＣ、電池ＡＢＣと比較電池を各５０個製作し、落下試験を実施した。落下試験は９０ｃｍの高さからタイル上に電池の端子キャップが下、外装缶底が下、胴面が下となるようにして各５回自由落下させ、試験前後での電池抵抗変化、漏液の有無を評価した。電池抵抗変化は落下前後で抵抗が１０ｍΩ以上増加した電池を異常と判定した。漏液は落下後に目視で電解液の漏れが確認できた電池を異常と判定した。落下試験の結果を表１に示す。
【００３６】
【表１】

【００３７】
電池Ａ、電池Ａ’では防爆弁体と電流遮断体の溶接で落下衝撃での電池の抵抗変化を大幅に抑制できた。電池Ｂ、電池Ｂ’では本発明の上部絶縁板で、落下時の電極群の衝撃から防爆弁体を保護し、電流遮断体の抵抗増加、電流遮断体の誤動作、防爆弁体の損傷による漏液を防止できた。電池Ｃの外装缶閉塞外周の凸部と端子キャップの段差の関係は電池抵抗変化の抑制にはそれほど寄与していないように理解されるが、電池Ｃの端子キャップの変形量は落下前後でいずれも０．０８ｍｍ以下で、比較電池の端子キャップの変形量は０．８ｍｍ〜１．１ｍｍであることから、落下時の端子キャップ側からの衝撃が原因と推定される電流遮断体の抵抗増加、電流遮断体の誤動作防止には効果があると考えられる。電池ＢＣでは防爆弁体と端子キャップの変形が原因となる電流遮断体の抵抗増加、電流遮断体の誤動作を防止できた。電池ＡＢＣでは落下で衝撃を加えても落下前後の電池の抵抗変化が１０ｍΩ以下となり、電解液の漏液も皆無にできた。
【００３８】
上記の結果から明らかなように、本実施例の密閉型非水二次電池は、落下試験で衝撃を加えても落下前後の抵抗変化が小さく、電解液の漏液の発生がない。本実施例の密閉型非水二次電池は落下試験後も問題無く使用することができた。
【００３９】
【発明の効果】
以上説明してきたように、本発明は落下等の衝撃が加わっても、抵抗変化が小さく、漏液の発生しない密閉型非水二次電池を提供することができる。本発明の密閉型非水二次電池は高さ９０ｃｍ程度であれば落下後も再使用可能である。
【図面の簡単な説明】
【図１】本発明の密閉型非水二次電池の概略断面図である。
【図２】本発明の防爆弁体と電流遮断体の電気的な接続の一例で、防爆弁体と電流遮断体の第一導通体をレーザ溶接したものである。
【図３】本発明の防爆弁体と電流遮断体の電気的な接続の一例で、防爆弁体と電流遮断体の第一導通体を超音波溶着したものである。
【図４】本発明の電極群と防爆弁体の間に配置される上部絶縁板の一例である。
【図５】本発明の上部絶縁板を組み込んだ電池の断面図である。
【図６】本発明の上部絶縁板の一例で上部絶縁板に金属製リングをインサートして射出成形したものである。
【図７】本発明の外装缶閉塞外周の凸部と端子キャップの段差の関係を示した図である。
【符号の説明】
１外装缶
２電極群
２ａ正極
２ｂ負極
２ｃセパレータ
３ａ上部絶縁板（従来）
３ｂ上部絶縁板（本発明）
４リード板
５ガスケット
６防爆弁体
７電流遮断体
７ａ第一導通体
７ｂ第二導通体
７ｃ中間絶縁体
７ｄ正温度係数抵抗体（ＰＴＣ素子）
８端子キャップ
８ａ排気孔
９溝状肉薄部
１０外装絶縁リング
１１外装チューブ
１２レーザ溶接部
１３超音波溶着部
１４金属製リング
１５外装缶閉塞外周の凸部と端子キャップの段差[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a safe and durable battery, and more particularly, to a sealed nonaqueous secondary battery that can maintain performance without damaging the inside of the battery even when an impact such as dropping is applied.
[0002]
[Prior art]
In recent years, high performance, downsizing, and portability of electronic devices have led to demand for high energy density secondary batteries to replace conventional nickel cadmium batteries and lead storage batteries as batteries used as power sources. ing. Therefore, research and development of nickel-metal hydride batteries using hydrogen storage alloys for the negative electrode and non-aqueous secondary batteries using materials that can insert and release light metals for the positive and negative electrodes have recently been conducted and used in some electronic devices. It came to be. In particular, a sealed non-aqueous secondary battery using lithium insertion and release has a high battery voltage of 3.6 V and a high energy density. Therefore, the battery can be reduced in size and weight, and it has less self-discharge and cycle characteristics. Therefore, it is expected to be widely used as a power source for portable devices in the future.
Even if a conventional non-aqueous secondary battery such as a nickel cadmium battery or a nickel metal hydride battery is accidentally dropped, the leakage of the electrolyte, circuit voltage, and change in internal resistance are small as long as it is at a certain height. Designed and manufactured so that it can be reused without sacrificing performance. However, because of the high energy density of lithium secondary batteries, complicated parts such as pressure-sensitive valve bodies, current interrupters, and positive temperature resistance coefficient elements are incorporated in the sealing portion, leaving a problem in impact resistance. Yes.
As a result of diligent research on the impact resistance, the present inventor has found that there is a problem in the damage of the explosion-proof valve body due to the movement of the electrode group due to the impact and the increase in the contact resistance of the sealing body inserted in the gasket. Invented.
[0003]
[Problems to be solved by the invention]
The present invention provides a sealed non-aqueous secondary battery having a structure that does not cause leakage of electrolyte or increase in battery resistance even when an impact is applied while ensuring the safety of the non-aqueous secondary battery. It is what.
[0004]
[Problems to be solved by the invention]
An object of the invention is to provide an electrode group formed by winding positive and negative electrodes and a separator, an upper insulating plate and a nonaqueous electrolyte solution in a bottomed battery outer can, and a sealing body fitted and supported by an insulating gasket. In the sealed nonaqueous secondary battery in which the opening of the bottom battery outer can is closed, the sealing body includes a positive terminal cap with an exhaust hole, a positive temperature resistance coefficient element (PTC element), a current interrupter, It consists of an explosion-proof valve body, Further, the current interrupter and the explosion-proof valve body are welded. This was solved by a sealed non-aqueous secondary battery.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Although the preferable form of this invention is demonstrated below, this invention is not necessarily limited to these.
(1) An electrode group formed by winding positive and negative electrodes and a separator, an upper insulating plate, and a non-aqueous electrolyte are housed in a bottomed battery outer can, and the bottomed battery is sealed by a sealing body fitted and supported by an insulating gasket. In a sealed nonaqueous secondary battery in which an opening of an outer can is closed, the sealing body includes a positive terminal cap with an exhaust hole, a positive temperature resistance coefficient element (PTC element), a current interrupter, and an explosion-proof valve. The body, Further, the current interrupter and the explosion-proof valve body are welded. A sealed non-aqueous secondary battery characterized by the above.
(2) With respect to the explosion-proof valve body and the current interrupting body constituting the sealing body according to item 1, the explosion-proof valve body is deformed in the opposite direction to the electrode group side as the battery internal pressure increases, A first conductive body disposed between the explosion-proof valve body and the PTC element and disposed on the explosion-proof valve body side and having a through hole, an intermediate insulator having a through hole in the center, and disposed on the PTC element side And a second conductive body having a through hole and a three-layer laminated structure, wherein the first conductive body and the second conductive body are electrically connected at a central portion. Water secondary battery.
(3) A sealed non-aqueous secondary battery, wherein the explosion-proof valve body of Item 2 and the first conducting body of the current interrupting body are welded.
(4) The explosion-proof valve body and the first conducting body of the current interrupting body are made of aluminum or an alloy thereof. Any one A sealed nonaqueous secondary battery according to 1.
(5) The upper insulating plate disposed between the electrode group described in Item 1 and the explosion-proof valve body is provided with a convex portion on the explosion-proof valve body side at a portion facing the peripheral portion of the dish-shaped body of the explosion-proof valve body, And having a plurality of holes. Any one A sealed nonaqueous secondary battery according to 1.
(6) The convex portion of the outer periphery of the closed bottom battery case can comprises a bottom battery case, an insulating ring, and a heat shrinkable tube that covers a part of the body surface and end face of the battery from the outside of the insulating ring. The step between the convex portion and the terminal cap constituting the sealing body is +1.0 to −0.5 mm with respect to the highest portion of the convex portion on the outer periphery of the closed bottom of the bottomed battery outer can. Any one of claims 1 to 5 A sealed nonaqueous secondary battery according to 1.
[0006]
Hereinafter, the present invention will be described in detail.
Although there may be various kinds of impacts, in the present invention, resistance to impacts caused by dropping from a desk or the like will be described, but the present invention is not limited to dropping impacts.
In the present invention, in order to improve the safety of the battery, the sealing body is made up of a positive terminal cap with an exhaust hole, a positive temperature resistance coefficient element (PTC element), a current interruption body, and an explosion-proof valve body. The positive temperature resistance coefficient element has a function of cutting off current by increasing resistance when the temperature in the battery rises. The current interrupting body is a laminated structure of a first conducting body, an intermediate insulator, and a second conducting body. The first conducting body is disposed on the explosion-proof valve body side and has a through hole. The second conducting body is a positive temperature resistance. It is a structure which is arrange | positioned at the coefficient element side, ie, the positive terminal cap side, and has a through-hole. The first conducting body and the second conducting body are electrically connected at the central portion, and have a thin portion around the connection portion of the first conducting body. The explosion-proof valve body can be deformed to the side opposite to the electrode group side when the internal pressure rises, and may be any one that can push up the first conductive body central connection part of the above-described current interrupter, but particularly near the outer peripheral part. A dish-like body having a projecting flat part projecting from the electrode group side to the center part of the projecting flat part, preferably having an action body that can act on the first conductive body central connection part of the current interrupter when the internal pressure rises. Furthermore, it is preferable that the explosion-proof valve body described in Japanese Patent Application No. Hei 6-294611 has a protrusion that protrudes toward the current interrupter at the center of the flat protrusion. The explosion-proof valve body and the current interrupting body cut off the current by breaking the connecting part of the first conducting body and the second conducting body of the current interrupting body when the internal pressure rises due to an abnormal reaction in the battery. When the pressure is further increased, the thin portion of the valve body is destroyed and the pressure is released. At this time, since the current interrupting body is disposed on the side opposite to the electrode group side of the explosion-proof valve body, the battery is prevented from being ruptured due to the ignition of the electrolyte vapor in the interrupting portion.
[0007]
Even in a battery with the built-in safety mechanism, the electrode group pushes and deforms the explosion-proof valve body due to an impact such as dropping, causing the current interrupter to malfunction, causing damage to the explosion-proof valve body and causing liquid leakage, making it impossible to use There was a case where it became. As countermeasures, an explosion-proof valve body protective frame was attached to the valve body or incorporated in the sealing body, but the caulking strength of the sealing body was lowered, and the suitability of the assembly process was difficult.
In the present invention, a plate-shaped upper insulating plate serving also as an insulation between the electrode group and the outer can or the sealing body is disposed between the electrode group and the explosion-proof valve body, and the explosion-proof valve body side is disposed near the outer periphery of the upper insulating plate. Is provided with a convex portion, and this convex portion faces the peripheral edge portion of the dish-shaped body of the explosion-proof valve body. The tip of the convex portion and the dish-shaped body of the explosion-proof valve body may be in contact with each other. When not in contact, the distance between the tip of the projection and the dish is preferably 1 mm or less. The upper insulating plate of the present invention has two or more holes, preferably three or more holes. At least one of the holes has a diameter of 2 mm or more, preferably 4 mm or more.
Insulating plate of the present invention having a convex portion, the central portion of the insulating plate is pushed up by the electrode group, the central portion of the plate-shaped body of the explosion-proof valve body is deformed to cause the current interrupter to malfunction or damage the explosion-proof valve body It is possible to solve the problem of leakage. The upper insulating plate is generally made by injection molding of a resin. At that time, a metal ring-shaped part or the like is inserted and molded so as to maintain insulation, and the rigidity of the upper insulating plate itself is increased. It is effective to raise. As the metal to be inserted, a highly corrosion resistant material such as stainless steel is suitable.
[0008]
Since the battery of the present invention incorporates the safety mechanism of the above-described various parts in the sealing part, it is important to ensure conduction between the parts. Usually, a method of laminating several kinds of sealing parts in an insulating gasket and caulking and closing these sealing parts with a battery outer can through the gasket is common. In order to prevent the contact resistance between the components from changing or increasing, these sealing bodies are configured to avoid contact between the aluminums that originally form an oxide film with poor conductivity. When aluminum or an alloy thereof is used, it is usual to use nickel or a material having good conductivity with nickel plating or the like for the parts in contact with the parts to reduce and stabilize the contact resistance between the parts.
[0009]
The present invention provides a laminated structure of a sealing body that connects aluminum and its alloy sealing parts in contact with each other by welding, thereby reducing resistance between the sealing parts even if an external impact such as dropping is applied. In addition to being made stable and small, the use of aluminum or its alloys further ensures the operation of the safety mechanism. JIS standard 1000 series aluminum was used for the first conductor of the explosion-proof valve body and the current interrupter to be welded. As the welding means, laser welding or ultrasonic welding is preferable.
Preferred conditions for laser welding are as follows. This was possible under the conditions of a voltage of 250 V to 290 V and a pulse width of 1 msec to 3 msec. Further, better welding strength and electrical continuity were obtained under the conditions of a voltage of 260 V to 280 V and a pulse width of 1.5 msec to 2 msec.
Preferred conditions for ultrasonic welding are as follows. Welding was performed by pressing the horn from the explosion-proof valve body side and receiving the current interrupter side with an anvil. Welding is possible under the conditions of horn pressing force 30N-50N, amplitude 8μm-12μm, energy 5J-25J, frequency 40KHz, and horn pressing force 40N-50N, amplitude 8μm-10μm, energy 15J-25J, frequency 40KHz. Better weld strength and electrical continuity were obtained.
[0010]
In addition to the above, the cause of the deterioration of the battery performance due to the impact is the deformation of the negative electrode terminal cap and the accompanying deformation of the sealing body. In the present invention, these deformations are determined from +1.0 mm to −0 .0 with respect to the level difference between the convex portion on the outer periphery of the outer can closed and the terminal cap, and the convex portion on the outer periphery of the outer can closed (the highest position when the battery is set up). It improved by setting it as 5 mm. The step is more preferably +0.5 mm to −0.3 mm, particularly preferably +0.15 mm to 0 mm. Here, + indicates a state in which the terminal cap protrudes, and-indicates a state in which the terminal cap is retracted. It is possible to make the convex curve at the center of the sealing body toward the electrode group side lower than the step when dropped, thereby eliminating the resistance increase of the current breaker itself and malfunctioning of the current breaker. If the step is +1.0 mm or more, the resistance increase of the current interrupter itself at the time of dropping increases, and sometimes the current interrupter malfunctions. If the step exceeds -0.5 mm, the connectivity with the external terminal is poor. The thickness of the insulating ring placed on the convex part on the outer periphery of the outer can closing for the insulation and the thickness of the heat-shrinkable tube covering the body surface and part of the end surface of the battery from the outer side of the insulating ring. It is also possible to adjust with. If the convex portion on the outer periphery of the outer can closure is higher than the terminal cap, lead welding to the terminal cap becomes difficult. Therefore, the terminal cap is preferably higher than the convex portion on the outer periphery of the outer can closure. The insulating ring is preferably paper or plastic, and polypropylene is preferable among the plastics.
[0011]
The positive and negative electrodes used in the non-aqueous secondary battery of the present invention can be prepared by coating a positive electrode mixture or a negative electrode mixture on a current collector or molding it into a pellet. In addition to the positive electrode active material or the negative electrode material, the positive electrode or the negative electrode mixture can contain a conductive agent, a binder, a dispersant, a filler, an ionic conductive agent, a pressure enhancer, and various additives, respectively.
[0012]
The active material in the positive electrode that can be used in the present invention may be any material that can insert and release light metals, but is preferably a lithium-containing transition metal oxide, more preferably Li _x CoO ₂ , Li _x NiO ₂ , Li _x Co _a Ni _1-a O ₂ , Li _x Co _b V _1-b O _z , Li _x Co _b Fe _1-b O _z , Li _x Mn ₂ O ₄ , Li _x MnO ₂ , LiMn ₂ O ₃ , Li _x Mn _b Co _2-b O _z , Li _x Mn _b Ni _2-b O _z , Li _x Mn _b V _2-b O _z , Li _x Mn _b Fe _1-b O _z (Where x = 0.05 to 1.2, a = 0.1 to 0.9, b = 0.8 to 0.98, z = 1.5 to 5).
Hereinafter, the light metal referred to in the present invention is an element belonging to Group 1A (excluding hydrogen) and Group 2A of the periodic table, preferably lithium, sodium, and potassium, and particularly preferably lithium.
[0013]
The active material in the negative electrode that can be used in the present invention may be any material that can insert and release light metals, but preferably graphite (natural graphite, artificial graphite, vapor-grown graphite), coke (coal or petroleum), organic polymer. Baked products (polyacrylonitrile resin or fiber, furan resin, cresol resin, phenol resin), mesophase pitch fired product, metal oxide, metal chalcogenide, lithium-containing transition metal oxide and chalcogenide.
In particular, an oxide or chalcogenide made of Ge, Sn, Pb, Bi, Al, Ga, Si, or Sb alone or a combination thereof is preferable. Furthermore, SiO known as a network former in these ₂ , B ₂ O ₃ , P ₂ O ₅ , Al ₂ O ₃ , V ₂ O ₅ Those made amorphous by adding such as are particularly preferred. These may be of stoichiometric composition or non-stoichiometric compounds.
Preferred examples of these compounds include the following, but the present invention is not limited thereto.
[0014]
GeO, GeO ₂ , SnO, SnO ₂ , SnSiO ₃ , PbO, SiO, Sb ₂ O ₅ , Bi ₂ O ₃ , Li ₂ SiO ₃ , Li ₄ Si ₂ O ₇ , Li ₂ GeO ₃ , SnAl _0.4 B _0.5 P _0.5 K _0.1 O _3.65 , SnAl _0.4 B _0.5 P _0.5 Cs _0.1 O _3.65 , SnAl _0.4 B _0.5 P _0.5 K _0.1 Ge _0.05 O _3.85 , SnAl _0.4 B _0.5 P _0.5 K _0.1 Mg _0.1 Ge _0.02 O _3.83 , SnAl _0.4 B _0.4 P _0.4 Ba _0.08 O _3.28 , SnAl _0.5 B _0.4 P _0.5 Mg _0.1 F _0.2 O _3.65 , SnAl _0.4 B _0.5 P _0.5 Cs _0.1 Mg _0.1 F _0.2 O _3.65 , SnB _0.5 P _0.5 Cs _0.05 Mg _0.05 F _0.1 O _3.03 , Sn _1.1 Al _0.4 B _0.4 P _0.4 Ba _0.08 O _3.34 , Sn _1.2 Al _0.5 B _0.3 P _0.4 Cs _0.2 O _3.5 , SnSi _0.5 Al _0.2 B _0.1 P _0.1 Mg _0.1 O _2.8 , SnSi _0.5 Al _0.3 B _0.4 P _0.5 O _4.30 , SnSi _0.6 Al _0.1 B _0.1 P _0.1 Ba _0.2 O _2.95 , SnSi _0.6 Al _0.4 B _0.2 Mg _0.1 O _3.2 , Sn _0.9 Mn _0.3 B _0.4 P _0.4 Ca _0.1 Rb _0.1 O _2.95 , Sn _0.9 Fe _0.3 B _0.4 P _0.4 Ca _0.1 Rb _0.1 O _2.95 , Sn _0.3 Ge _0.7 Ba _0.1 P _0.9 O _3.35 , Sn _0.9 Mn _0.1 Mg _0.1 P _0.9 O _3.35 , Sn _0.2 Mn _0.8 Mg _0.1 P _0.9 O _3.35 .
[0015]
Furthermore, the negative electrode material of the present invention can be used by inserting a light metal, particularly lithium. The lithium insertion method is preferably an electrochemical, chemical or thermal method.
[0016]
The amount of lithium inserted into the negative electrode material of the present invention may be close to the lithium deposition potential, but is preferably 50 to 700 mol% per the above preferred negative electrode material. 100 to 600 mol% is particularly preferable.
[0017]
The conductive agent in the positive electrode and the negative electrode that can be used in the present invention is graphite, acetylene black, carbon black, ketjen black, carbon fiber or metal powder, metal fiber or polyphenylene derivative, and graphite and acetylene black are particularly preferable.
The binder in the positive electrode and the negative electrode that can be used in the present invention is polyacrylic acid, carboxymethyl cellulose, polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl alcohol, starch, regenerated cellulose, diacetyl cellulose, hydroxypropyl cellulose, polyvinyl chloride, polyvinyl Pyrrolidone, polyethylene, polypropylene, SBR, EPDM, sulfonated EPDM, fluororubber, polybutadiene, polyethylene oxide are preferable, and polyacrylic acid, carboxymethylcellulose, polytetrafluoroethylene, and polyvinylidene fluoride are particularly preferable.
[0018]
The positive electrode and negative electrode support or current collector that can be used in the present invention is made of aluminum, stainless steel, nickel, titanium, or an alloy thereof for the positive electrode, and copper, stainless steel, nickel, titanium for the negative electrode. Or an alloy of these, and the form is foil, expanded metal, punching metal, or wire mesh. In particular, an aluminum foil is preferable for the positive electrode and a copper foil is preferable for the negative electrode.
The separator that can be used in the present invention is only required to be an insulating thin film having a large ion permeability, a predetermined mechanical strength, and an olefin polymer, a fluorine polymer, a cellulose polymer, polyimide, nylon, Glass fiber and alumina fiber are used, and as a form, a nonwoven fabric, a woven fabric, and a microporous film are used. In particular, the material is preferably polypropylene, polyethylene, a mixture of polypropylene and polyethylene, a mixture of polypropylene and Teflon, or a mixture of polyethylene and Teflon, and the form is preferably a microporous film. In particular, a microporous film having a pore diameter of 0.01 to 1 μm and a thickness of 5 to 50 μm is preferable.
[0019]
The electrolyte solution that can be used in the present invention includes, as an organic solvent, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, 1,2-dimethoxyethane, γ-butyrolactone, tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl sulfoxide, Dioxolane, 1,3-dioxolane, formamide, dimethylformamide, nitromethane, acetonitrile, methyl formate, methyl acetate, methyl propionate, phosphate ester, trimethoxymethane, dioxolane derivative, sulfolane, 3-methyl-2-oxazolidinone, propylene carbonate Derivatives, tetrahydro derivatives, diethyl ether, a mixture of at least one of 1,3-propane sultone, and electrolytes LiClO ₄ , LiBF ₄ , LiPF ₆ , LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , LiAsF ₆ , LiSbF ₆ , LiB ₁₀ Cl ₁₀ , Lower aliphatic lithium carboxylate, LiAlCl ₄ , LiCl, LiBr, LiI, chloroborane lithium, and lithium tetraphenylborate in which one or more salts are dissolved are preferable. In particular, LiCF is used as a mixed solvent of propylene carbonate or ethylene carbonate and 1,2-dimethoxyethane and / or diethyl carbonate. ₃ SO ₃ LiClO ₄ , LiBF ₄ And / or LiPF ₆ In which at least ethylene carbonate and LiPF are dissolved. ₆ It is preferable to contain.
[0020]
The shape of the battery can be applied to any of buttons, coins, sheets, cylinders, and corners. For buttons and coins, the mixture is pressed into a pellet and used. For sheets, corners, and cylinders, the mixture is coated on a current collector, dried, dehydrated and pressed. The battery is formed by inserting a pellet, a sheet or an electrode wound together with a separator into a battery can, electrically connecting the can and the electrode, injecting an electrolyte, and sealing. The battery preferably includes a current interruption mechanism and an internal pressure release explosion-proof valve body as means for ensuring safety even in the case of malfunction.
[0021]
The bottomed battery outer can that can be used in the present invention is made of steel plate, stainless steel plate (SUS304, SUS304L, SUS304N, SUS316, SUS316L, SUS430, SUS444, etc.) plated with nickel, Same as above), aluminum or alloys thereof, nickel, titanium, and copper, and the shapes are a perfect circular cylinder, an elliptical cylinder, a square cylinder, and a rectangular cylinder. In particular, when the outer can also serves as the negative electrode terminal, a stainless steel plate and a nickel-plated steel plate are preferable, and when the outer can also serves as the positive electrode terminal, a stainless steel plate, aluminum, or an alloy thereof is preferable.
[0022]
Gaskets that can be used in the present invention are olefin polymers, fluoropolymers, cellulosic polymers, polyimides, and polyamides as materials. Olefin polymers are preferred from the viewpoint of organic solvent resistance and low moisture permeability, and are mainly composed of propylene. Polymers are preferred. Furthermore, a block copolymer of propylene and ethylene is preferable.
[0023]
The battery of the present invention is covered with an exterior material as necessary. Examples of the exterior material include a heat-shrinkable tube, an adhesive tape, a metal film, paper, cloth, paint, and a plastic case. Further, at least a part of the exterior may be provided with a portion that changes color by heat so that the heat history during use can be known.
A plurality of the batteries of the present invention are assembled in series and / or in parallel as needed, and stored in a battery pack. In addition to safety elements such as positive temperature coefficient resistors, temperature fuses, fuses and / or current interrupting elements, the battery pack also requires safety circuits (monitoring the voltage, temperature, current, etc. of each battery and / or the entire battery pack) In this case, a circuit having a function of interrupting current may be provided. In addition to the positive and negative terminals of the entire assembled battery, the battery pack should be provided with the positive and negative terminals of each battery, the entire assembled battery, the temperature detection terminal of each battery, the current detection terminal of the entire assembled battery, etc. as external terminals. You can also. The battery pack may incorporate a voltage conversion circuit (such as a DC-DC converter). The connection of each battery may be fixed by welding a lead plate, or may be fixed so that it can be easily attached and detached with a socket or the like. Further, the battery pack may be provided with display functions such as the remaining battery capacity, the presence / absence of charging, and the number of uses.
[0024]
The battery of the present invention is used in various devices. In particular, video movies, portable video decks with built-in monitors, movie cameras with built-in monitors, compact cameras, single-lens reflex cameras, disposable cameras, film with lenses, notebook computers, notebook-type word processors, electronic notebooks, mobile phones, cordless phones, whiskers, It is preferably used for electric tools, electric mixers, automobiles and the like.
[0025]
【Example】
Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the examples unless it exceeds the gist of the invention.
First, how to make the electrode will be explained, and then how to assemble the battery will be explained.
SnB as negative electrode active material _0.2 P _0.5 K _0.1 Mg _0.1 Ge _0.1 O _2.8 86 parts by weight, 3 parts by weight of acetylene black as a conductive agent and 6 parts by weight of graphite, and 4 parts by weight of polyvinylidene fluoride as an aqueous dispersion of 0.2 μm as a binder and carboxymethylcellulose 1 Part by weight was added and kneaded using water as a medium to obtain a slurry. The slurry was coated on both sides of a copper foil having a thickness of 10 μm by using an extrusion coater, dried, and then compression molded by a calendar press to prepare a strip-shaped negative electrode.
87 parts by weight of LiCoO 2 as a positive electrode active material, 3 parts by weight of acetylene black and 6 parts by weight of graphite as a conductive agent were mixed, and 3 parts by weight of Nipol 820B (manufactured by ZEON) and 1 part by weight of carboxymethyl cellulose were added as binders. In addition, a slurry was obtained by kneading with water as a medium. The slurry was coated on both sides of an aluminum foil having a thickness of 20 μm using an extrusion coater, and after drying, compression-molded by a calendar press to produce a strip-shaped positive electrode.
[0026]
Each of the negative electrode and the positive electrode was welded with nickel and aluminum lead plates at the ends, and then heat-treated at 230 ° C. for 1 hour in dry air having a dew point of −40 ° C. or less. The heat treatment was performed using a far infrared heater. Further, a heat-treated positive electrode, a microporous polyethylene / polypropylene film separator, a heat-treated negative electrode and a separator were laminated in this order, and this was wound in a spiral shape.
This wound body was housed in a nickel-plated iron-bottomed cylindrical battery can also serving as a negative electrode terminal. Furthermore, 1 mol / liter LiPF as the electrolyte ₆ (2 to 8 weight ratio mixed solution of ethylene carbonate and diethyl carbonate) was poured into the battery can. A cylindrical battery was prepared by caulking the battery lid having the positive electrode terminal through a gasket. The positive electrode terminal was connected to the positive electrode and the battery can was connected to the negative electrode in advance by a lead terminal.
[0027]
Comparative battery
In order to confirm the effect of the present invention, a comparative non-aqueous secondary battery for comparison not incorporating the present invention was manufactured by the following procedure. This will be described below with reference to FIG. In the comparative battery, a positive electrode (2a) and a negative electrode (2b) are wound via a separator (2c), and an electrode group in which a polypropylene base acrylic adhesive tape is wound is provided with a thickness of 0.3 mm above and below the electrode group. The flat insulator (3a) having holes made of polypropylene was placed in an outer can (1) having an outer diameter of about 16.5 mm together with a non-aqueous electrolyte, and further, asphalt was applied to the opening of the outer can A sealing body composed of a plurality of sealing parts was arranged through an insulating gasket, and the outer can was caulked inside to close and sealed. The total height of the battery after caulking was about 670 mm. In order to prevent a short circuit outside the sealing part, a polypropylene ring (10) for insulation is placed on the convex part of the outer periphery of the outer can closing, and further, the battery body surface and a part of the end face are cross-linked from the outside. Covered with a polyethylene heat shrink tube (11). An insulating ring placed on the convex portion of the outer periphery of the outer can closing at this time, and a terminal cap including the thickness of the heat shrinkable tube covering a part of the body surface and the end surface of the battery from the outer side of the insulating ring; The step (15 in FIG. 7) was +1.2 mm.
[0028]
Battery A
Battery A is an embodiment of a battery manufactured by ensuring electrical connection between the explosion-proof valve body and the current interrupting body of the present invention. As shown in FIG. 2, the explosion-proof valve body (6) and the current interrupting body (7) are overlapped with each other while holding down with a constant force, and both of the explosion-proof valve body and the current interrupting body made of JIS standard 1000 series aluminum are used. The outer periphery of the one conductor (7a) was spot-welded at two points with a YAG laser welder. The welding in this embodiment was performed under the conditions of a voltage of 280 V and a pulse width of 1.5 msec at which particularly good welding strength and electrical continuity were obtained. A battery was manufactured in the same procedure as the comparative battery except that a welded explosion-proof valve body and a current interrupting body were incorporated.
[0029]
Battery A '
Battery A ′ is another embodiment of the battery manufactured by ensuring the electrical connection between the explosion-proof valve body and the current interrupting body of the present invention. As shown in FIG. 3, after the explosion-proof valve body and the current interrupting body are overlapped, two ultrasonic waves are applied to the vicinity of the outer periphery of the first conducting body of the explosion-proof valve body and the current interrupting body made of JIS standard 1000 series. Welded. The welding in this embodiment was performed under the conditions of a horn pressing force of 40 N, an amplitude of 9 μm, an energy of 15 J, and a frequency of 40 KHz at which particularly good welding strength and electrical conduction were obtained. A battery was fabricated in the same procedure as the comparative battery, except that a welded explosion-proof valve body and a current interrupting body were incorporated.
[0030]
Battery B
Battery B is an example of a battery manufactured by incorporating an upper insulating plate having a convex portion in the vicinity of the outer peripheral portion of the present invention. FIG. 4 shows the upper insulating plate used in the present embodiment, and FIG. 5 is a view in which the upper insulating plate is incorporated in a battery. The shape of the upper insulating plate (3b) of the present example is 15 mm in outer shape, the convex portion is 1.5 mm to 2.5 mm from the outer periphery and 1 mm in width, and its height is 1.5 mm from the bottom of the upper insulating plate. And the distance with the explosion-proof valve body which opposes is 0 mm-0.5 mm in a convex part. The upper insulating plate of FIG. 4 was manufactured by injection molding polypropylene. A battery was manufactured in the same procedure as the comparative battery except that the upper insulating plate of FIG. 4 was incorporated.
[0031]
Battery B '
Battery B ′ is another embodiment of the battery manufactured by incorporating an upper insulating plate having a convex portion in the vicinity of the outer peripheral portion of the present invention. FIG. 6 shows the upper insulating plate used in this example. In order to increase the rigidity of the upper insulating plate, the outer surface of the upper insulating plate is 11 mm in outer diameter and 5 mm in inner diameter so that the insulating property of the surface facing the electrode group is not impaired. A ring having a thickness of 0.3 mm is inserted and injection molded. It was manufactured in the same shape as the upper insulating plate of battery B except that a metal ring was inserted. A battery was manufactured in the same procedure as the comparative battery except that the upper insulating plate of FIG. 6 was incorporated.
[0032]
Battery C
Battery C is an embodiment of the battery that employs the relationship between the protrusions on the outer periphery of the outer can closing of the present invention and the step difference of the terminal cap. FIG. 7 shows the relationship of the steps in this embodiment. The insulating ring placed on the outer can-closed outer peripheral convex part is made of polypropylene and has an outer diameter of 15 mm, an inner diameter of 9 mm, and a thickness of 0.5 mm. The heat-shrinkable tube that covers a part of the body surface and end face of the battery from the outer side of the insulating ring is made of cross-linkable polyethylene and has a thickness of 0.15 mm after heat-shrinking. The step between the protrusion on the outer periphery of the outer can closing after the insulation ring and the heat-shrinkable tube are attached and the terminal cap are +0.08 mm, and the terminal cap protrudes outside. A battery was manufactured in the same procedure as the comparative battery except that the steps in FIG. 7 were used.
[0033]
Battery BC
The battery BC is an example of a battery that employs the relationship between the upper insulating plate of the battery B, the convex portion of the outer periphery of the outer cover of the battery C, and the step of the terminal cap. A battery was manufactured in the same procedure as that of the comparative battery except that the upper insulating plate of battery B was incorporated and the level difference of battery C was set.
[0034]
Battery ABC
The battery ABC incorporates an explosion-proof valve body and a current interrupting body, which are laser welded to the battery A, and uses a relationship between the upper insulating plate of the battery B, the convex portion of the outer periphery of the outer cover of the battery C, and the step of the terminal cap. This is an example. A battery was manufactured in the same procedure as the comparative battery except that the explosion-proof valve body of battery A, the current interrupting body, and the upper insulating plate of battery B were incorporated, and the battery C was stepped.
[0035]
50 batteries A, Battery A ′, Battery B, Battery B ′, Battery C, Battery BC, Battery ABC, and Comparative Battery of the above Example were manufactured, and a drop test was performed. In the drop test, from the height of 90 cm, the battery terminal cap is on the tile, the outer can bottom is down, and the body surface is down. The presence or absence of was evaluated. As for battery resistance change, a battery whose resistance increased by 10 mΩ or more before and after dropping was judged as abnormal. As for leakage, a battery in which leakage of the electrolyte was confirmed visually after dropping was judged as abnormal. The results of the drop test are shown in Table 1.
[0036]
[Table 1]

[0037]
In Battery A and Battery A ′, the resistance change of the battery due to drop impact could be greatly suppressed by welding the explosion-proof valve body and the current interrupter. In the batteries B and B ′, the upper insulating plate of the present invention protects the explosion-proof valve body from the impact of the electrode group when dropped, increases the resistance of the current breaker, malfunctions of the current breaker, and leakage due to damage to the explosion-proof valve body The liquid could be prevented. It is understood that the relationship between the protrusions on the outer periphery of the outer cover closing of the battery C and the step of the terminal cap does not contribute much to the suppression of the battery resistance change, but the deformation amount of the terminal cap of the battery C is Is 0.08 mm or less, and the deformation amount of the terminal cap of the comparative battery is 0.8 mm to 1.1 mm. Therefore, the resistance increase of the current interrupter estimated to be caused by the impact from the terminal cap side when dropped, This is thought to be effective in preventing malfunction of the current interrupter. In the battery BC, it was possible to prevent an increase in resistance of the current breaker and a malfunction of the current breaker due to deformation of the explosion-proof valve body and the terminal cap. In the battery ABC, even when an impact was applied by dropping, the resistance change of the battery before and after dropping was 10 mΩ or less, and no electrolyte leakage occurred.
[0038]
As is clear from the above results, the sealed nonaqueous secondary battery of this example has a small resistance change before and after dropping even when an impact is applied in the drop test, and there is no leakage of electrolyte. The sealed non-aqueous secondary battery of this example could be used without any problems after the drop test.
[0039]
【The invention's effect】
As described above, the present invention can provide a sealed nonaqueous secondary battery in which resistance change is small and no leakage occurs even when an impact such as dropping is applied. The sealed non-aqueous secondary battery of the present invention can be reused even after dropping if it is about 90 cm in height.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a sealed nonaqueous secondary battery of the present invention.
FIG. 2 is an example of an electrical connection between an explosion-proof valve body and a current interrupter according to the present invention, in which a first conductive body of an explosion-proof valve body and a current interrupter is laser welded.
FIG. 3 is an example of electrical connection between an explosion-proof valve body and a current interrupting body according to the present invention, in which an explosion-proof valve body and a first conducting body of a current interrupting body are ultrasonically welded.
FIG. 4 is an example of an upper insulating plate disposed between the electrode group of the present invention and an explosion-proof valve body.
FIG. 5 is a cross-sectional view of a battery incorporating the upper insulating plate of the present invention.
FIG. 6 shows an example of the upper insulating plate according to the present invention, in which a metal ring is inserted into the upper insulating plate and injection molded.
FIG. 7 is a view showing the relationship between the protrusions on the outer periphery of the outer can closed according to the present invention and the step difference between the terminal caps.
[Explanation of symbols]
1 Exterior can
2 Electrode group
2a positive electrode
2b negative electrode
2c separator
3a Upper insulating plate (conventional)
3b Upper insulating plate (present invention)
4 Lead plate
5 Gasket
6 Explosion-proof valve body
7 Current interrupter
7a First conductor
7b Second conductor
7c Intermediate insulator
7d Positive temperature coefficient resistor (PTC element)
8 Terminal cap
8a Exhaust hole
9 Grooved thin part
10 Exterior insulation ring
11 Exterior tube
12 Laser weld
13 Ultrasonic weld
14 Metal ring
15 Projection on outer periphery of outer can closed and step between terminal cap

Claims

正負電極とセパレータを巻回してなる電極群と、上部絶縁板と非水電解液が有底電池外装缶内に収納され、絶縁性ガスケットに嵌入支持された封口体により該有底電池外装缶の開口部が閉塞されてなる密閉型非水二次電池において、該封口体が、排気孔付き正極端子キャップと、正温度抵抗係数素子（ＰＴＣ素子）と、電流遮断体と、防爆弁体とからなり、さらに該電流遮断体と該防爆弁体とが溶接されていることを特徴とする密閉型非水二次電池。An electrode group formed by winding positive and negative electrodes and a separator, an upper insulating plate and a non-aqueous electrolyte are housed in a bottomed battery outer can, and the bottomed battery outer can is sealed by a sealing body fitted and supported by an insulating gasket. In a sealed non-aqueous secondary battery in which an opening is closed, the sealing body includes a positive terminal cap with an exhaust hole, a positive temperature resistance coefficient element (PTC element), a current interruption body, and an explosion-proof valve body. Further , the sealed non-aqueous secondary battery, wherein the current interrupter and the explosion-proof valve body are welded .

請求項１の封口体を構成する防爆弁体と電流遮断体に関し、該防爆弁体が電池内圧の上昇に伴って電極群側とは反対方向に変形し、該電流遮断体は、該防爆弁体と該ＰＴＣ素子との間に配置され、かつ該防爆弁体側に配置され貫通孔を有する第一導通体と、中央部に貫通孔を有する中間絶縁体と、該ＰＴＣ素子側に配置され貫通孔を有する第二導通体との３層の積層構造体であり、該第一導通体と該第二導通体は中央部で電気的に接続されていることを特徴とする密閉型非水二次電池。An explosion-proof valve body and a current interrupting body constituting the sealing body according to claim 1, wherein the explosion-proof valve body is deformed in a direction opposite to the electrode group side as the battery internal pressure increases, and the current interrupting body includes the explosion-proof valve A first conducting body disposed between the body and the PTC element and disposed on the explosion-proof valve body side and having a through hole, an intermediate insulator having a through hole in the center, and a penetrating hole disposed on the PTC element side A sealed non-aqueous two-layer structure having a three-layer structure including a second conductor having holes, wherein the first conductor and the second conductor are electrically connected at a central portion. Next battery.

請求項２の防爆弁体と電流遮断体の第一導通体とが溶接されていることを特徴とする密閉型非水二次電池。A sealed non-aqueous secondary battery, wherein the explosion-proof valve body of claim 2 and the first conducting body of a current interrupting body are welded.

該防爆弁体と該電流遮断体の第一導通体とがアルミニウム又はその合金からなることを特徴とする請求項１から３のいずれか１項に記載の密閉型非水二次電池。-Proof explosion valve and sealed non-aqueous secondary battery according to any one of claims 1 to 3, and the first conductive body is characterized in that it consists of aluminum or an alloy thereof of the current blocking member.

請求項１に記載の電極群と防爆弁体の間に配置される上部絶縁板は、防爆弁体の皿状体の周辺部に対向する部分で防爆弁体側に凸部が設けられ、かつ複数の孔を有することを特徴とする請求項１から４のいずれか１項に記載の密閉型非水二次電池。The upper insulating plate disposed between the electrode group according to claim 1 and the explosion-proof valve body is provided with a convex portion on the explosion-proof valve body side at a portion facing the peripheral portion of the dish-shaped body of the explosion-proof valve body, and a plurality of sealed non-aqueous secondary battery according to claim 1, any one of 4, characterized in that it has a hole.

有底電池外装缶閉塞外周の凸部は、有底電池外装缶と絶縁性リングと該絶縁性リングの更に外側から電池の胴面及び端面の一部を覆う熱収縮チューブから構成され、該凸部と封口体を構成する端子キャップとの段差が、該有底電池外装缶閉塞外周の凸部の最も高い部分を基準として＋１．０から−０．５ｍｍであることを特徴とする請求項１から５のいずれか１項に記載の密閉型非水二次電池。The convex portion on the outer periphery of the closed bottom battery case can comprises a bottom battery case, an insulating ring, and a heat shrinkable tube that covers a part of the body surface and the end surface of the battery from the outside of the insulating ring. claim step between terminal cap constituting the parts and the sealing body, characterized in that the highest part of the convex portion of the bottomed battery outer can closed periphery is -0.5mm from +1.0 as a reference 1 6. The sealed nonaqueous secondary battery according to any one of items 1 to 5 .