JP3656459B2

JP3656459B2 - Square non-aqueous electrolyte battery and battery module

Info

Publication number: JP3656459B2
Application number: JP14028999A
Authority: JP
Inventors: 竹規石津; 満小関
Original assignee: Shin Kobe Electric Machinery Co Ltd
Current assignee: Resonac Corp
Priority date: 1999-05-20
Filing date: 1999-05-20
Publication date: 2005-06-08
Anticipated expiration: 2019-05-20
Also published as: JP2000331661A

Description

【０００１】
【発明の属する技術分野】
本発明は角形非水電解液電池及び電池モジュールに係り、特に、正極板、負極板及びセパレータを積層し角形電池ケース内に収容された電極群と、該電極群から導電され前記電池ケース上面に固定された正極及び負極端子と、を備えた角形非水電解液電池及び角形非水電解液電池を複数個組み合わせ、該各角形非水電解液電池及び該角形非水電解液電池全体を制御する制御回路を備えた電池モジュールに関する。
【０００２】
【従来の技術】
現在、非水電解液電池としてリチウム一次電池、リチウム二次電池などが実用化されている。これらの電池のうち、電気容量が１．５Ａｈ程度の小型リチウム二次電池では、例えば、ＰＴＣ(Positive Temperature Coefficient) 素子を発電素子と直列に挿入して温度上昇時に電流を遮断する電流遮断機構を付加したり、電池内部と外部との境界に金属薄膜を形成して電池の内圧上昇時に金属薄膜を破断させ電池内部の発生ガスを放出し、電池容器の損傷を防ぐ内圧低減機構を付加する等、非水電解液電池の安全性を確保している。
【０００３】
このように小型電池においても安全性を重視しており、電気容量が１０Ａｈを越えるような大型電池であれば、安全性を確保することが更に重要であることはいうまでもない。安全性を重視した大型電池として、例えば、特開平第９−９２２４９号公報には電池内部の発生ガスを放出するために開放弁を備えた二次電池の技術が開示されている。同公報の開放弁によれば、開放圧を再現性よく設定でき、開放圧力を低く設定できることから、圧力開放時の衝撃力を和らげることができる。
【０００４】
【発明が解決しようとする課題】
しかしながら、同公報の技術では開放弁の明確な位置を記述するには至っていない。また、同公報は円筒形電池についての技術であり、その構造上の特性から電池ケースの耐圧が低い角形電池では、安全性を確保するために、電池内部の発生ガスを放出する内圧低減機構がより一層重要となる。
【０００５】
更に、上記した金属薄膜を破断させて発生ガスを放出させる内圧低減機構では、その金属薄膜の配置位置又はその開裂機構を十分に考慮しなければ安全機能を発揮できない場合がある。すなわち、例えば、ある物体が金属薄膜の直上に配置された場合には、電池異常時に内圧が上昇し金属薄膜が破断して内部発生ガスを放出しようとしても、該物体がガス放出経路を遮断しているので放出することができず、電池容器自体の損傷を招くことも考えられる。また、該物体が非水電解液電池を安全に動作させるための制御回路である場合には、発生ガスが制御回路の真下から直接噴射することから、正常に作動していた制御回路を破壊又は制御不能の状態にし、電池の安全を確保することができない状態に至る。
【０００６】
また、電池異常時に内部発生したガスは、金属薄膜が破断すると同時に勢いよく放出する。このとき、電極群等の電池内容物は、流出ガスとともに圧力が下がった金属薄膜破断部方向に移動するので、ガス放出口を閉塞させ電池容器の損傷を引き起こす、という問題がある。
【０００７】
本発明は上記事案に鑑み、安全性に優れた角形非水電解液電池及び該角形非水電解液電池を備えた電池モジュールを提供することを目的とする。
【０００８】
【課題を解決するための手段】
上記目的を達成するために、本発明の第１の態様は、正極板、負極板及びセパレータを積層し角形電池ケース内に収容された電極群と、該電極群から導電され前記電池ケース上面に固定された正極及び負極端子と、を備えた角形非水電解液電池において、前記電池ケースは所定内圧で開裂する脆弱部を有し、該脆弱部のうち少なくとも１つは前記電池ケース上面に形成され、該電池ケース上面に形成された脆弱部のうち少なくとも１つは、該電池ケース内側に配置され前記脆弱部が開裂したときに該脆弱部の閉塞を防止する閉塞防止部材の直上に形成されており、前記閉塞防止部材は、一端が前記電極群中の負極板に接続され、他端が前記負極端子に接続された長尺状の導電部材であることを特徴とする。
【０００９】
本発明では、閉塞防止部材を電池ケース内側に配置し、その直上に脆弱部を形成したので、電池内圧の上昇により脆弱部が開裂したとき、ガス放出に伴う電池内容物が閉塞防止部材に係止されて開裂した脆弱部の閉塞が防止され、確実に内部発生ガスを放出することができる。また、この脆弱部を正極及び負極端子等を固定した電池ケース上面に少なくとも１つ形成することにより、直方体に近い角形電池の上面以外の５面が他の物体により密着され、その５面に形成された脆弱部が閉塞された場合においても、正極及び負極端子のような凹凸のある電池ケース上面は閉塞されずに、確実に内部発生ガスを電池外部へ放出することができる。更に、塞防止部材を、一端が電極群中の負極板に接続され、他端が負極端子に接続された長尺状の導電部材としたので、新たに閉塞防止部材を設ける必要がない。第１の態様において、導電部材を負極板の集電体と同一材質とすれば、電蝕を防止することができるので、閉塞防止部材が脆弱化することを防止することができる。
【００１０】
また、正極板、負極板及びセパレータを積層し角形電池ケース内に収容された電極群と、該電極群から導電され前記電池ケース上面に固定された正極及び負極端子と、を備えた角形非水電解液電池において、前記電池ケースは所定内圧で開裂する脆弱部を有し、該脆弱部のうち少なくとも１つは前記電池ケース上面に形成され、該電池ケース上面に形成された脆弱部のうち少なくとも１つは、該電池ケース内側に配置され前記脆弱部が開裂したときに該脆弱部の閉塞を防止する閉塞防止部材の直上に形成されており、前記閉塞防止部材は、一端が電極群中の負極板に接続され、他端が負極端子に接続された長尺状の導電部材と、該導電部材の直上かつ脆弱部の直下に、該導電部材とは絶縁されて、該導電部材の長手方向とねじれの位置に配置される長尺部材と、で構成されるようにしてもよい。
【００１１】
また、本発明の第２の態様は、上述した角形非水電解液電池を備えた電池モジュールである。本発明では、電池ケース上面に固定した正極及び負極端子の凹凸によりデッドスペースとなった空間を有効利用するため、その空間に各角形非水電解液電池及び角形非水電解液電池全体を制御する制御回路を配置することにより、高エネルギー密度の電池モジュールが実現される。また、この制御回路により各角形非水電解液電池の電池ケース上面に形成された少なくとも１つの脆弱部が閉塞されないように、各電池ケース上面に形成された少なくとも１つの脆弱部の直上以外で、各電池ケース上面のうち少なくとも１つの上面に配置したので、電池異常時に発生したガスを確実に放出させる経路を確保することができると共に、発生ガスが制御回路の直下から直接噴射することがないので、正常に作動していた制御回路を破壊又は制御不能の状態に至らしめる危険も回避することができる。このとき、制御回路は、該制御回路を保護する、例えば、難燃ＡＢＳ等の制御回路保護材を介して各電池ケース上面のうち少なくとも一つの上面に固定するようにすることが好ましい。
【００１２】
【発明の実施の形態】
以下、図面を参照して本発明が適用される電池モジュールの実施の形態について説明する。
【００１３】
図１に示すように、本実施形態の電池モジュール３０は、角形非水電解液電池２０を複数個備えている。この角形非水電解液電池２０は、図２に示すように、角形非水電解液電池２０の容器となる角形でステンレス製の電池缶７を有している。電池缶７の中央部には、矩形状で上部方向に耳部が張り出した正極板５及び負極板６を両極板が直接接触しないように図示しないセパレータを挟んで複数枚積層した電極群が収容されている。なお、正極板５はアルミニウム箔を正極集電体とし、正極集電体両面に正極活物質合剤が塗布されており、負極板５は銅箔を負極集電体とし、負極集電体両面に負極活物質合剤が塗布されている。また、角形非水電解液電池２０は、ステンレス製の電池蓋８を備えており、電極群を電池缶７に挿入した後、電池缶７の開口部周縁とこの電池蓋８周縁とを溶接することにより封口されている。
【００１４】
正極板５の耳部上端は厚さ２ｍｍの薄板状のアルミニウム板３に超音波接合されている。電池蓋８の一側には、アルミニウム製のねじ棒からなる正極端子１が図示しないシール材を介して電池蓋８と螺合するようにねじ穴が形成されている。正極端子１の先端部は電池蓋８の上部にナットにより固定されており、アルミニウム板３の超音波接合側反対端部と正極端子１の先端部反対端とはボルトとナットにより締め付け接触（図示なし）されている。一方、負極板６の耳部上端は厚さ２ｍｍの薄板状の銅板４に超音波接合されている。電池蓋８の正極端子１固定側とは反対側には、銅製のねじ棒からなる負極端子２が図示しないシール材を介して電池蓋８と螺合するようにねじ穴が形成されている。負極端子２の先端部は電池蓋８の上部にナットにより固定されており、銅板４の超音波接合側反対端部と負極端子２の先端部反対端とはボルトとナットにより締め付け接触（図示なし）されている。従って、正極端子１はアルミニウム板３を介して正極板５に、負極端子２は銅板４を介して負極板６に、それぞれ電気的に導通されている。
【００１５】
図３及び図４に示すように、電池蓋８には、ステンレス箔を溶接した薄膜円形状の脆弱部としての安全弁９が溶接されている。この安全弁９の下部には、「一」文字状（長尺状）で大きさが２ｍｍ×２ｍｍ×２５ｍｍのステンレス製の閉塞防止部材１０の両端上面部が電池蓋８の底面に固定されて配置されている。図３に示すように、安全弁９は閉塞防止部材１０及び銅板４それぞれの直上に配置され、閉塞防止部材１０と銅板４とは電気的に絶縁されている。また、図４に示すように、閉塞防止部材１０と銅板４とはねじれの位置関係にあり、それぞれの長手方向が交差するように配置されている。
【００１６】
なお、図２に示すように、電池蓋８には注液口１１が形成されており、本実施形態の角形非水電解液電池２０では、この注液口１１からエチレンカーボネートとジメチルカーボネートとの混合溶媒に６フッ化リン酸リチウム（ＬｉＰＦ_６）を溶解した電解液を注入し、電解液注入後、図示しない液口栓により注液口１１を密閉している。
【００１７】
また、図１に示すように、電池モジュール３０は、各角形非水電解液電池２０及びモジュール（角形非水電解液電池２０全体）を制御する長尺状の制御回路１２と、各角形非水電解液電池２０と制御回路１２との接触を防止すると共に、安全弁９が開裂してガスが放出されたときに放出ガスが制御回路１２に直接あたることを避けるための、厚さ２ｍｍで制御回路１２の幅と略同幅の難燃ＡＢＳ樹脂を材質とした制御回路保護部材１３と、を備えており、制御回路１２は制御回路保護部材１３を介して各角形非水電解液電池２０の電池蓋８の上面に固定されている。なお、電池モジュール３０は、各角形非水電解液電池２０の安全弁９が制御回路１２と平行に１列に並ぶように組み合わされ、制御回路１２は各角形非水電解液電池２０の安全弁９の直上の位置とはならない位置に、各安全弁９から隔離されて配置されている。
【００１８】
次に、本実施形態の角形非水電解液電池２０及び電池モジュール３０の作用について説明する。
【００１９】
角形非水電解液電池２０は、安全弁９が閉塞防止部材１０と銅板４とがそれぞれの長手方向に交差した直上に配置されているので、角形非水電解液電池２０の内圧が上昇して安全弁９が開裂したときに、電極群の内容物（正極活物質、負極活物質等）がガスとともに安全弁９の方向に移動しても、交差する閉塞防止部材１０及び銅板４に当接係止されて安全弁９の開裂部を閉塞することはない。従って、角形非水電解液電池２０内部のガスは確実に安全弁９から外部に放出されるので、角形非水電解液電池２０を損傷させることはない。また、アルミニウム板３及び銅板４はそれぞれ正極板５、負極板６の各集電体と同一材質（それぞれアルミニウム及び銅）としたので、電蝕犠牲となり脆弱化することない。従って、電極群の内容物がガスとともに安全弁９の方向に移動したときにも強度を保つことができる。また、閉塞防止部材１０を銅板４と絶縁するようにしたので、外部短絡を招くおそれもない。
【００２０】
一方、電池モジュール３０は、制御回路１２を各角形非水電解液電池２０のデッドスペースとなった空間に配置したので、高エネルギー密度の電池モジュールとすることができる。また、制御回路１２を安全弁９の位置とは離れた位置に配置したので、安全弁９の開裂時に安全弁９を外側から塞ぐこともなく、また、ガスの直接噴射により破壊や制御不能に至る状態を回避することができる。また、制御回路保護部材１３を難燃ＡＢＳ樹脂としたので、各角形非水電解液電池２０の電池蓋８に安全弁９を複数配置した場合でも、制御回路１２は電池蓋８との直接の接触が妨げられる。従って、偶々難燃ＡＢＳ樹脂を介して制御回路１２の下側に安全弁９が配置され開裂したときでも放出ガスが制御回路１２に直接あたることがないので、制御回路１２の機能を維持することができ、制御回路保護部材１３が発火することもない。
【００２１】
なお、本実施形態では、安全弁９の開裂時の閉塞を防止するために、銅板４とは別に電気的に独立した閉塞防止部材１０を設けた例について述べたが、閉塞防止部材１０を特に有しなくてもよい。すなわち、図５及び図６に示すように、角形非水電解液電池２１は、閉塞防止部材１０を有しておらず、銅板４が安全弁９の開裂時に電極群の内容物を係止させ閉塞しないようにしたものである。この角形非水電解液電池２１では、銅板４を負極板６から負極端子１への導電部材として使用すると共に、安全弁９の閉塞を防止するようにしたので、角形非水電解液電池２０より部品数を少なくすることができる。
【００２２】
[実施例]
次に、以上の実施形態に従って作製した各角形非水電解液電池２０（２１）及び電池モジュール３０の実施例について説明する。なお、実施例の効果について確認するために同時に作製した比較例の電池についても併記する。
【００２３】
（実施例１）上述した角形非水電解液電池２０と同一で、図２に示したように、安全弁９を負極端子２側に配置し、安全弁９が閉塞防止部材１０及び銅板４それぞれの直上に位置している電池。
【００２４】
（実施例２）図２において、電池蓋８のみを水平方向に１８０度回転し、正極端子１側に安全弁９を配置し、安全弁９が閉塞防止部材１０及びアルミニウム板３それぞれの直上に位置したこと以外は実施例１と同様に作製した電池。
【００２５】
（実施例３）図２において、正極端子１側と負極端子２側にそれぞれ１つずつ２個の安全弁９を設け、安全弁９が閉塞防止部材１０及びアルミニウム板３と銅板４それぞれの直上に配置したこと以外は実施例１と同様に作製した電池。
【００２６】
（実施例４）上述した角形非水電解液電池２１と同一で、図５に示したように、銅板４を導電部材かつ閉塞防止部材として用い、安全弁９が銅板４の直上に配置していること以外は実施例１と同様にして作製した電池。
【００２７】
（実施例５）図１において、実施例１の角形非水電解液電池２０（単電池）を８個組み合わせ、各単電池の安全弁９の位置を１列とし、制御回路１２は安全弁９の直上とはならない位置に配置し、制御回路保護部材１３を備えていない（制御回路１２と各電池蓋８とが直接接触している）電池モジュール。
【００２８】
（実施例６）図１において、実施例３の、安全弁９がそれぞれ正極端子側と負極端子側に配置された角形非水電解液電池を８個組み合わせ、２つの安全弁９のうち１つは、直上に制御回路１２を配置し、制御回路保護部材１３を備えていない電池モジュール。
【００２９】
（実施例７）図１において、実施例３の安全弁９がそれぞれ正極端子側と負極端子側とに配置された角形非水電解液電池を８個組み合わせ、２つの安全弁９のうちひとつは、直上に制御回路１２を配置し、制御回路保護部材１３を備えていること以外は実施例６と同様にして作製した電池モジュール。
【００３０】
（比較例１）図４に示したアルミニウム板３及び銅板４を用いずに電極群中の正極板５及び負極板６からリード（線）により直接それぞれ正極端子１及び負極端子２に導電させたこと以外は実施例４と同様に作製した電池。
【００３１】
＜試験・評価＞
[試験] 次に、以上のように作製した実施例及び比較例の各電池及び各電池モジュールについて外部短絡試験を実施した。この外部短絡試験では、電池モジュールについては、８個の単電池全てを同時には外部短絡させず、１個ずつ外部短絡させて試験を行った。単電池の検査方法として、外部短絡試験後、損傷、発火の有無を確認し、制御回路１２の検査方法として、各単電池の外部短絡試験後、制御回路１２を目視及び動作確認し、損傷、誤動作、動作不能の有無を確認した。
【００３２】
[試験結果] 外部短絡試験後の検査結果を表１に示す。なお、表１において、「○」は８０％以上損傷・発火なし、「△」は５０％以上８０％未満損傷・発火なし、「×」は５０％未満損傷・発火なし、「−」は制御回路１２を有しないため評価なし、「●」は制御回路１２の動作が正常、「◆」は制御回路１２が損傷及び／又は誤動作及び／又は動作不能となったものをそれぞれ示している。
【００３３】
【表１】

【００３４】
[評価]
単電池検査の結果、比較例１の電池は５０％以上の電池が損傷・発火した。実施例２の電池は５０％以上が損傷・発火せず、単電池の安全性が向上している。実施例１、３乃至７の電池は８０％以上が損傷・発火せず安全性が一段と高まっている。
【００３５】
また、制御回路検査の結果、実施例６の電池モジュールは制御回路１２が損傷し、誤動作又は動作不能となり、制御回路１２の機能を果たせない結果となった。実施例５、７の電池モジュールは、単電池の外部短絡試験後も制御回路１２が正常動作した。
【００３６】
このことから、単電池では、安全弁９開裂時の閉塞を妨げる機能を有する部材（アルミニウム板３及び／又は銅板４及び／又は閉塞防止部材１０）を設けることにより安全性が向上し、更に、その安全弁９を電池上面中央部より負極端子２側に配置することにより、一段と安全性が向上することが分かる。また、単電池を複数個組み合わせた電池モジュールでは、安全弁９の配置位置は、直上に制御回路１２がない位置に配置させること、また、安全弁９の直上に制御回路１２を配置させるときは、各電池と制御回路１２の間に制御回路保護部材１３を設けることにより制御回路１２を損傷、誤動作又は動作不能状態にさせず正常動作させることができ、安全性を向上させることができることが分かる。
【００３７】
なお、本実施形態では、ステンレス製薄膜を安全弁９として使用した例について説明したが、安全弁９は薄膜に限定されることなく、電池蓋８上面に形成され、電池蓋８より脆弱で所定電池内圧で開裂する部材を使用することができる。
【００３８】
また、本実施形態では、閉塞防止部材１０にステンレスを使用したが、他の金属、耐熱性樹脂、難燃性樹脂等も使用してもよい。
【００３９】
更に、本実施形態では、制御回路保護部材１３に難燃ＡＢＳ樹脂を使用したが、制御回路保護部材１３の材質としては、金属、他の耐熱性樹脂や難燃性樹脂なども使用可能である。なお、制御回路保護部材１３に金属を使用するときは、制御回路１２内の金属部と接触させないように制御回路保護部材１３の形状を考慮することが好ましい。
【００４０】
なお、本発明は上述の実施形態に限らず本発明の要旨を逸脱することなくその他種々の構成を採り得ることはいうまでもない。
【００４１】
【発明の効果】
以上説明したように、本発明の第１の態様によれば、閉塞防止部材を電池ケース内側に配置し、その直上に脆弱部を形成したので、電池内圧の上昇により脆弱部が開裂したとき、ガス放出に伴う電池内容物が閉塞防止部材に係止されて開裂した脆弱部の閉塞が防止され、確実に内部発生ガスを放出することができると共に、閉塞防止部材を、一端が電極群中の負極板に接続され、他端が負極端子に接続された長尺状の導電部材としたので、新たに閉塞防止部材を設ける必要がない、という効果を得ることができる。また、本発明の第２の態様によれば、各電池ケース上面に形成された少なくとも１つの脆弱部の直上以外で、各電池ケース上面のうち少なくとも１つの上面に、各角形非水電解液電池及び角形非水電解液電池全体を制御する制御回路を配置したので、デッドスペースを有効利用できるのみならず、電池異常時に発生したガスを確実に放出させる経路を確保することができると共に、発生ガスが制御回路の直下から直接噴射することがないので、正常に作動していた制御回路を破壊又は制御不能の状態に至らしめる危険も回避することができる、という効果を得ることができる。
【図面の簡単な説明】
【図１】本発明を適用した電池モジュールの外観斜視図である。
【図２】実施形態の電池モジュールを構成する角形非水電解液電池の一部破断正面図である。
【図３】角形非水電解液電池の安全弁付近の拡大側断面図である。
【図４】角形非水電解液電池の安全弁付近を電極群側から見たときの拡大図である。
【図５】本発明を適用した別の実施形態の角形非水電解液電池の一部破断正面図である。
【図６】別の実施形態の角形非水電解液電池の安全弁付近を電極群側から見たときの拡大図である。
【符号の説明】
１正極端子
２負極端子
３アルミニウム板（閉塞防止部材の一部）
４銅板（導電部材、閉塞防止部材の一部）
５正極板
６負極板
７電池缶（角形電池ケースの一部）
８電池蓋（角形電池ケースの一部）
９安全弁（脆弱部）
１０閉塞防止部材
１２制御回路
１３制御回路保護部材
２０、２１角形非水電解液電池
３０電池モジュール[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a prismatic non-aqueous electrolyte battery and a battery module, and more particularly, an electrode group in which a positive electrode plate, a negative electrode plate, and a separator are stacked and accommodated in a prismatic battery case; A plurality of prismatic nonaqueous electrolyte batteries and prismatic nonaqueous electrolyte batteries each having a fixed positive electrode and a negative electrode terminal are combined to control each of the prismatic nonaqueous electrolyte batteries and the entire prismatic nonaqueous electrolyte battery. The present invention relates to a battery module provided with a control circuit.
[0002]
[Prior art]
Currently, lithium primary batteries, lithium secondary batteries, and the like are put to practical use as non-aqueous electrolyte batteries. Among these batteries, a small lithium secondary battery having an electric capacity of about 1.5 Ah has, for example, a current cutoff mechanism that interrupts current when the temperature rises by inserting a PTC (Positive Temperature Coefficient) element in series with the power generation element. Addition of an internal pressure reduction mechanism to prevent damage to the battery container by forming a metal thin film at the boundary between the inside and outside of the battery and breaking the metal thin film when the internal pressure of the battery rises to release gas generated inside the battery This ensures the safety of non-aqueous electrolyte batteries.
[0003]
As described above, safety is emphasized also in a small battery, and it goes without saying that it is more important to ensure safety if the battery has a large capacity with an electric capacity exceeding 10 Ah. As a large battery with an emphasis on safety, for example, Japanese Patent Application Laid-Open No. 9-92249 discloses a technology of a secondary battery provided with an open valve in order to release gas generated inside the battery. According to the open valve of the publication, the open pressure can be set with good reproducibility, and the open pressure can be set low, so that the impact force when the pressure is released can be reduced.
[0004]
[Problems to be solved by the invention]
However, the technique of the publication does not describe a clear position of the open valve. In addition, this publication is a technology for a cylindrical battery, and in order to ensure safety in a prismatic battery whose battery case has a low withstand voltage due to its structural characteristics, an internal pressure reduction mechanism that releases the generated gas inside the battery is provided. It becomes even more important.
[0005]
Furthermore, in the internal pressure reduction mechanism that breaks the metal thin film and releases the generated gas, the safety function may not be exhibited unless the arrangement position of the metal thin film or the cleavage mechanism is sufficiently considered. That is, for example, when an object is placed immediately above the metal thin film, even if the internal pressure rises when the battery is abnormal and the metal thin film breaks and tries to release the internally generated gas, the object blocks the gas release path. Therefore, it cannot be released, and the battery container itself may be damaged. In addition, when the object is a control circuit for safely operating the nonaqueous electrolyte battery, the generated gas is directly injected from directly under the control circuit. It will be in an uncontrollable state and will be in the state which cannot ensure the safety of a battery.
[0006]
Further, the gas generated inside when the battery is abnormal is released vigorously as the metal thin film breaks. At this time, the battery contents such as the electrode group move in the direction of the metal thin film rupture portion where the pressure is reduced together with the outflow gas, so that there is a problem that the gas discharge port is closed and the battery container is damaged.
[0007]
An object of the present invention is to provide a prismatic non-aqueous electrolyte battery excellent in safety and a battery module including the prismatic non-aqueous electrolyte battery.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a first aspect of the present invention includes an electrode group in which a positive electrode plate, a negative electrode plate, and a separator are stacked and housed in a rectangular battery case, and is electrically conductive from the electrode group on the upper surface of the battery case. In a prismatic non-aqueous electrolyte battery comprising a fixed positive electrode and a negative electrode terminal, the battery case has a fragile portion that is cleaved at a predetermined internal pressure, and at least one of the fragile portions is formed on the upper surface of the battery case. And at least one of the fragile portions formed on the upper surface of the battery case is formed immediately above the blocking prevention member disposed inside the battery case and preventing the fragile portion from being blocked when the fragile portion is cleaved. The blocking prevention member is a long conductive member having one end connected to the negative electrode plate in the electrode group and the other end connected to the negative electrode terminal.
[0009]
In the present invention, the blockage preventing member is disposed inside the battery case, and the fragile portion is formed immediately above the battery case. Therefore, when the fragile portion is cleaved due to an increase in the battery internal pressure, the battery contents accompanying gas release are related to the blockage preventing member. Closure of the weakened portion that is stopped and cleaved is prevented, and the internally generated gas can be reliably released. In addition, by forming at least one weak portion on the upper surface of the battery case to which the positive electrode and the negative electrode terminal are fixed, five surfaces other than the upper surface of the rectangular battery close to a rectangular parallelepiped are brought into close contact with other objects and formed on the five surfaces. Even when the weakened portion is closed, the internally generated gas can be reliably discharged outside the battery without blocking the uneven battery case upper surface such as the positive electrode and the negative electrode terminal. Furthermore, since the blocking prevention member is a long conductive member having one end connected to the negative electrode plate in the electrode group and the other end connected to the negative electrode terminal, there is no need to newly provide a blocking prevention member. In the first aspect, if the conductive member is made of the same material as that of the current collector of the negative electrode plate, it is possible to prevent electric corrosion, thereby preventing the blockage preventing member from becoming weak.
[0010]
In addition, a rectangular non-aqueous device comprising: an electrode group in which a positive electrode plate, a negative electrode plate, and a separator are stacked and accommodated in a rectangular battery case; and a positive electrode and a negative electrode terminal that are conductive from the electrode group and are fixed to the upper surface of the battery case. In the electrolyte battery, the battery case has a fragile portion that is cleaved at a predetermined internal pressure, and at least one of the fragile portions is formed on the upper surface of the battery case, and at least of the fragile portions formed on the upper surface of the battery case. One is formed directly above the blocking prevention member that is disposed inside the battery case and prevents the fragile portion from being blocked when the fragile portion is cleaved, and one end of the blocking prevention member is in the electrode group. A long conductive member connected to the negative electrode plate and having the other end connected to the negative electrode terminal, and the conductive member is insulated immediately above the conductive member and directly below the fragile portion. And twisted position An elongated member is, in may be constituted.
[0011]
Moreover, the 2nd aspect of this invention is a battery module provided with the square nonaqueous electrolyte battery mentioned above. In the present invention, in order to effectively use a space that becomes a dead space due to the unevenness of the positive and negative terminals fixed on the upper surface of the battery case, each rectangular nonaqueous electrolyte battery and the entire rectangular nonaqueous electrolyte battery are controlled in the space. By disposing the control circuit, a battery module with a high energy density is realized. In addition, other than directly above at least one fragile portion formed on the upper surface of each battery case, so that at least one fragile portion formed on the upper surface of the battery case of each rectangular nonaqueous electrolyte battery is not blocked by this control circuit, Since it is arranged on at least one of the upper surfaces of each battery case, it is possible to secure a path for reliably releasing the gas generated when the battery is abnormal, and the generated gas is not directly injected from directly under the control circuit. In addition, it is possible to avoid the danger of causing the control circuit that has been operating normally to be destroyed or uncontrollable. At this time, it is preferable that the control circuit is fixed to at least one of the upper surfaces of the battery cases via a control circuit protection material such as flame retardant ABS, which protects the control circuit.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of a battery module to which the present invention is applied will be described with reference to the drawings.
[0013]
As shown in FIG. 1, the battery module 30 of this embodiment includes a plurality of rectangular nonaqueous electrolyte batteries 20. As shown in FIG. 2, the rectangular nonaqueous electrolyte battery 20 includes a rectangular and stainless steel battery can 7 that serves as a container for the rectangular nonaqueous electrolyte battery 20. The central portion of the battery can 7 accommodates an electrode group in which a positive electrode plate 5 and a negative electrode plate 6 that are rectangular in shape and projecting in the upper direction are stacked with a separator (not shown) interposed therebetween so that the two electrode plates do not directly contact each other. Has been. The positive electrode plate 5 has an aluminum foil as a positive electrode current collector, and a positive electrode active material mixture is applied to both surfaces of the positive electrode current collector. The negative electrode plate 5 has a copper foil as a negative electrode current collector, and both surfaces of the negative electrode current collector. The negative electrode active material mixture is coated on the surface. The rectangular nonaqueous electrolyte battery 20 includes a stainless steel battery cover 8, and after the electrode group is inserted into the battery can 7, the periphery of the opening of the battery can 7 and the periphery of the battery cover 8 are welded. Is sealed.
[0014]
The upper end of the ear portion of the positive electrode plate 5 is ultrasonically bonded to a thin plate-like aluminum plate 3 having a thickness of 2 mm. A screw hole is formed on one side of the battery lid 8 so that the positive electrode terminal 1 made of an aluminum screw rod is screwed to the battery lid 8 via a sealing material (not shown). The tip of the positive electrode terminal 1 is fixed to the upper portion of the battery lid 8 with a nut, and the opposite end of the aluminum plate 3 on the ultrasonic bonding side and the opposite end of the positive electrode terminal 1 are tightened and contacted by bolts and nuts (illustrated). None). On the other hand, the upper end of the ear portion of the negative electrode plate 6 is ultrasonically bonded to a thin plate-like copper plate 4 having a thickness of 2 mm. A screw hole is formed on the opposite side of the battery lid 8 to the fixed side of the positive electrode terminal 1 so that the negative electrode terminal 2 made of a copper screw rod is screwed to the battery lid 8 via a sealing material (not shown). The tip of the negative electrode terminal 2 is fixed to the upper part of the battery lid 8 with a nut, and the opposite end of the copper plate 4 on the ultrasonic bonding side and the opposite end of the negative electrode terminal 2 are tightened and contacted with a bolt and a nut (not shown) ) Therefore, the positive electrode terminal 1 is electrically connected to the positive electrode plate 5 via the aluminum plate 3, and the negative electrode terminal 2 is electrically connected to the negative electrode plate 6 via the copper plate 4.
[0015]
As shown in FIGS. 3 and 4, the battery lid 8 is welded with a safety valve 9 as a thin fragile portion of a thin film welded with a stainless steel foil. At the bottom of the safety valve 9, an upper surface of both ends of a stainless steel blockage prevention member 10 having a “one” character shape (long shape) and a size of 2 mm × 2 mm × 25 mm is fixed to the bottom surface of the battery lid 8. Has been. As shown in FIG. 3, the safety valve 9 is disposed directly above the blockage preventing member 10 and the copper plate 4, and the blockage preventing member 10 and the copper plate 4 are electrically insulated. Moreover, as shown in FIG. 4, the blocking prevention member 10 and the copper plate 4 are in a twisted positional relationship, and are arranged so that their longitudinal directions intersect each other.
[0016]
As shown in FIG. 2, the battery lid 8 is formed with a liquid injection port 11, and in the rectangular non-aqueous electrolyte battery 20 of the present embodiment, ethylene carbonate and dimethyl carbonate are injected from the liquid injection port 11. An electrolyte solution in which lithium hexafluorophosphate (LiPF ₆ ) is dissolved is injected into the mixed solvent. After the electrolyte solution is injected, the liquid injection port 11 is sealed with a liquid port stopper (not shown).
[0017]
As shown in FIG. 1, the battery module 30 includes a rectangular control circuit 12 that controls each rectangular nonaqueous electrolyte battery 20 and the module (the entire rectangular nonaqueous electrolyte battery 20), and each rectangular nonaqueous electrolyte. A control circuit having a thickness of 2 mm for preventing contact between the electrolyte battery 20 and the control circuit 12 and for preventing the released gas from directly hitting the control circuit 12 when the safety valve 9 is cleaved and the gas is released. And a control circuit protection member 13 made of a flame retardant ABS resin having a width substantially the same as the width of 12, and the control circuit 12 is a battery of each rectangular nonaqueous electrolyte battery 20 via the control circuit protection member 13. It is fixed to the upper surface of the lid 8. The battery module 30 is combined so that the safety valves 9 of each rectangular nonaqueous electrolyte battery 20 are arranged in a line in parallel with the control circuit 12, and the control circuit 12 is connected to the safety valve 9 of each rectangular nonaqueous electrolyte battery 20. At a position that is not directly above the position, it is isolated from each safety valve 9.
[0018]
Next, the operation of the rectangular nonaqueous electrolyte battery 20 and the battery module 30 of the present embodiment will be described.
[0019]
In the rectangular nonaqueous electrolyte battery 20, the safety valve 9 is arranged immediately above the obstruction prevention member 10 and the copper plate 4 in the respective longitudinal directions, so that the internal pressure of the rectangular nonaqueous electrolyte battery 20 increases and the safety valve 9 Even when the contents of the electrode group (positive electrode active material, negative electrode active material, etc.) move in the direction of the safety valve 9 together with the gas when the 9 is cleaved, they are contacted and locked to the crossing blocking prevention member 10 and the copper plate 4. Thus, the cleaving portion of the safety valve 9 is not blocked. Therefore, the gas inside the rectangular nonaqueous electrolyte battery 20 is surely released from the safety valve 9 to the outside, so that the rectangular nonaqueous electrolyte battery 20 is not damaged. Further, since the aluminum plate 3 and the copper plate 4 are made of the same material (aluminum and copper, respectively) as the current collectors of the positive electrode plate 5 and the negative electrode plate 6, respectively, they are not sacrificed by electric corrosion. Therefore, the strength can be maintained even when the contents of the electrode group move in the direction of the safety valve 9 together with the gas. Further, since the blocking prevention member 10 is insulated from the copper plate 4, there is no possibility of causing an external short circuit.
[0020]
On the other hand, since the battery module 30 arrange | positions the control circuit 12 in the space used as the dead space of each square nonaqueous electrolyte battery 20, it can be set as a high energy density battery module. In addition, since the control circuit 12 is arranged at a position away from the position of the safety valve 9, the safety valve 9 is not blocked from the outside when the safety valve 9 is opened, and the state in which the gas is directly destroyed or cannot be controlled by the gas injection. It can be avoided. Further, since the control circuit protection member 13 is made of flame retardant ABS resin, the control circuit 12 is in direct contact with the battery lid 8 even when a plurality of safety valves 9 are arranged on the battery lid 8 of each square nonaqueous electrolyte battery 20. Is disturbed. Therefore, even if the safety valve 9 is accidentally placed under the control circuit 12 via the flame retardant ABS resin and is cleaved, the released gas does not directly hit the control circuit 12, so that the function of the control circuit 12 can be maintained. The control circuit protection member 13 is not ignited.
[0021]
In the present embodiment, the example in which the blocking prevention member 10 that is electrically independent from the copper plate 4 is provided in order to prevent the safety valve 9 from being blocked at the time of tearing has been described. You don't have to. That is, as shown in FIGS. 5 and 6, the rectangular nonaqueous electrolyte battery 21 does not have the blocking member 10, and the copper plate 4 locks the contents of the electrode group when the safety valve 9 is opened. This is what I did not. In this rectangular nonaqueous electrolyte battery 21, the copper plate 4 is used as a conductive member from the negative electrode plate 6 to the negative electrode terminal 1, and the safety valve 9 is prevented from being blocked. The number can be reduced.
[0022]
[Example]
Next, examples of each rectangular nonaqueous electrolyte battery 20 (21) and battery module 30 manufactured according to the above embodiment will be described. In addition, in order to confirm the effect of an Example, it writes together also about the battery of the comparative example produced simultaneously.
[0023]
(Embodiment 1) Same as the above-described rectangular non-aqueous electrolyte battery 20, and as shown in FIG. 2, the safety valve 9 is arranged on the negative electrode terminal 2 side, and the safety valve 9 is directly above the blocking member 10 and the copper plate 4, respectively. Located in the battery.
[0024]
(Embodiment 2) In FIG. 2, only the battery lid 8 is rotated 180 degrees in the horizontal direction, the safety valve 9 is disposed on the positive electrode terminal 1 side, and the safety valve 9 is positioned immediately above the blocking prevention member 10 and the aluminum plate 3, respectively. A battery produced in the same manner as in Example 1 except that.
[0025]
(Embodiment 3) In FIG. 2, two safety valves 9 are provided on each of the positive electrode terminal 1 side and the negative electrode terminal 2 side, and the safety valves 9 are arranged immediately above the blockage preventing member 10, the aluminum plate 3, and the copper plate 4, respectively. A battery produced in the same manner as in Example 1 except that.
[0026]
(Embodiment 4) The same as the rectangular nonaqueous electrolyte battery 21 described above, and as shown in FIG. 5, the copper plate 4 is used as a conductive member and a blocking prevention member, and the safety valve 9 is disposed immediately above the copper plate 4. A battery produced in the same manner as in Example 1 except that.
[0027]
(Embodiment 5) In FIG. 1, eight prismatic nonaqueous electrolyte batteries 20 (unit cells) of Example 1 are combined, the positions of the safety valves 9 of each unit cell are arranged in one row, and the control circuit 12 is directly above the safety valve 9. The battery module is arranged at a position where the control circuit protection member 13 is not provided (the control circuit 12 and each battery cover 8 are in direct contact).
[0028]
(Embodiment 6) In FIG. 1, the safety valve 9 of the embodiment 3 is combined with eight rectangular non-aqueous electrolyte batteries in which the safety valve 9 is disposed on the positive electrode terminal side and the negative electrode terminal side, respectively, and one of the two safety valves 9 is A battery module in which the control circuit 12 is arranged directly above and the control circuit protection member 13 is not provided.
[0029]
(Embodiment 7) In FIG. 1, the safety valve 9 of the embodiment 3 is composed of eight rectangular non-aqueous electrolyte batteries arranged on the positive electrode terminal side and the negative electrode terminal side, respectively. A battery module manufactured in the same manner as in Example 6 except that the control circuit 12 is disposed in the battery and the control circuit protection member 13 is provided.
[0030]
(Comparative Example 1) Without using the aluminum plate 3 and the copper plate 4 shown in FIG. 4, the positive electrode 5 and the negative electrode 6 in the electrode group were directly conducted to the positive electrode terminal 1 and the negative electrode terminal 2 by leads (wires), respectively. A battery produced in the same manner as in Example 4 except that.
[0031]
<Test and evaluation>
[Test] Next, an external short-circuit test was performed on each battery and each battery module of Examples and Comparative Examples manufactured as described above. In this external short-circuit test, the battery module was tested by externally short-circuiting each of the eight single cells one by one, not simultaneously. As an inspection method of the single cell, after the external short-circuit test, the presence or absence of damage or ignition is confirmed. As an inspection method of the control circuit 12, after the external short-circuit test of each single cell, the control circuit 12 is visually and confirmed to operate, Checked for malfunctions and inoperability.
[0032]
[Test Results] Table 1 shows the test results after the external short circuit test. In Table 1, “◯” indicates 80% or more without damage / ignition, “△” indicates 50% or more and less than 80% damage / ignition, “×” indicates less than 50% damage / ignition, and “-” indicates control. Since the circuit 12 is not provided, there is no evaluation, “●” indicates that the operation of the control circuit 12 is normal, and “♦” indicates that the control circuit 12 is damaged and / or malfunctions and / or becomes inoperable.
[0033]
[Table 1]

[0034]
[Evaluation]
As a result of the unit cell inspection, 50% or more of the batteries of Comparative Example 1 were damaged or ignited. 50% or more of the batteries of Example 2 are not damaged or ignited, and the safety of the unit cells is improved. More than 80% of the batteries of Examples 1, 3 to 7 are not damaged or ignited, and the safety is further increased.
[0035]
Further, as a result of the control circuit inspection, the battery module of Example 6 was damaged in the control circuit 12 and malfunctioned or inoperable, and the function of the control circuit 12 could not be performed. In the battery modules of Examples 5 and 7, the control circuit 12 operated normally even after the external short-circuit test of the unit cells.
[0036]
From this, in the cell, safety is improved by providing a member (aluminum plate 3 and / or copper plate 4 and / or blockage preventing member 10) having a function of preventing blockage when the safety valve 9 is opened. It can be seen that the safety is further improved by disposing the safety valve 9 on the negative electrode terminal 2 side from the center of the battery upper surface. Further, in a battery module in which a plurality of unit cells are combined, the safety valve 9 is disposed at a position where the control circuit 12 is not directly above, and when the control circuit 12 is disposed directly above the safety valve 9, It can be seen that by providing the control circuit protection member 13 between the battery and the control circuit 12, the control circuit 12 can be operated normally without being damaged, malfunctioned or disabled, and safety can be improved.
[0037]
In this embodiment, an example in which a stainless thin film is used as the safety valve 9 has been described. However, the safety valve 9 is not limited to a thin film, and is formed on the upper surface of the battery lid 8 and is weaker than the battery lid 8 and has a predetermined battery internal pressure. A member that can be cleaved at can be used.
[0038]
In the present embodiment, stainless steel is used for the blocking prevention member 10, but other metals, heat resistant resins, flame retardant resins, and the like may be used.
[0039]
Further, in the present embodiment, flame retardant ABS resin is used for the control circuit protection member 13, but as the material of the control circuit protection member 13, metal, other heat resistant resin, flame retardant resin, or the like can be used. . In addition, when using a metal for the control circuit protection member 13, it is preferable to consider the shape of the control circuit protection member 13 so that it may not contact the metal part in the control circuit 12. FIG.
[0040]
Needless to say, the present invention is not limited to the above-described embodiment, and various other configurations can be adopted without departing from the gist of the present invention.
[0041]
【The invention's effect】
As described above, according to the first aspect of the present invention, the blocking prevention member is arranged inside the battery case, and the fragile portion is formed immediately above, so when the fragile portion is cleaved due to an increase in the battery internal pressure, The battery contents accompanying the gas release are locked by the clogging prevention member to prevent the fragile portion from being clogged, and the internally generated gas can be surely released , and the clogging prevention member has one end in the electrode group. Since the long conductive member is connected to the negative electrode plate and the other end is connected to the negative electrode terminal, it is possible to obtain an effect that it is not necessary to newly provide a blocking member . Further, according to the second aspect of the present invention, each rectangular nonaqueous electrolyte battery is provided on at least one upper surface of each battery case other than directly above at least one fragile portion formed on each battery case upper surface. And a control circuit for controlling the entire rectangular non-aqueous electrolyte battery, not only can the dead space be used effectively, but also a path for reliably discharging the gas generated when the battery is abnormal can be secured, and the generated gas However, since there is no direct injection from directly under the control circuit, it is possible to obtain an effect that it is possible to avoid the risk of causing the control circuit that has been operating normally to be destroyed or uncontrollable.
[Brief description of the drawings]
FIG. 1 is an external perspective view of a battery module to which the present invention is applied.
FIG. 2 is a partially cutaway front view of a rectangular nonaqueous electrolyte battery constituting the battery module of the embodiment.
FIG. 3 is an enlarged cross-sectional side view of the vicinity of a safety valve of a rectangular nonaqueous electrolyte battery.
FIG. 4 is an enlarged view of the vicinity of a safety valve of a rectangular nonaqueous electrolyte battery as viewed from the electrode group side.
FIG. 5 is a partially broken front view of a prismatic nonaqueous electrolyte battery according to another embodiment to which the present invention is applied.
FIG. 6 is an enlarged view when the vicinity of a safety valve of a prismatic nonaqueous electrolyte battery according to another embodiment is viewed from the electrode group side.
[Explanation of symbols]
1 Positive Terminal 2 Negative Terminal 3 Aluminum Plate (Part of Blocking Prevention Member)
4 Copper plate (conductive member, part of blocking prevention member)
5 Positive electrode plate 6 Negative electrode plate 7 Battery can (part of rectangular battery case)
8 Battery cover (part of the square battery case)
9 Safety valve (fragile part)
DESCRIPTION OF SYMBOLS 10 Blocking prevention member 12 Control circuit 13 Control

circuit protection member

20, 21 Square nonaqueous electrolyte battery 30 Battery module

Claims

A rectangular non-aqueous electrolyte comprising: an electrode group in which a positive electrode plate, a negative electrode plate, and a separator are stacked and accommodated in a rectangular battery case; and a positive electrode and a negative electrode terminal that are conductive from the electrode group and are fixed to the upper surface of the battery case In the battery, the battery case has a fragile portion that is cleaved at a predetermined internal pressure, and at least one of the fragile portions is formed on the upper surface of the battery case, and at least one of the fragile portions formed on the upper surface of the battery case. Is formed directly above a blocking prevention member that is disposed inside the battery case and prevents the fragile portion from being blocked when the fragile portion is cleaved , and one end of the blocking prevention member is a negative electrode in the electrode group. A rectangular non-aqueous electrolyte battery characterized in that it is a long conductive member connected to a plate and having the other end connected to the negative electrode terminal .

The rectangular nonaqueous electrolyte battery according to claim 1 , wherein the blocking prevention member is made of the same material as the current collector of the negative electrode plate.

A rectangular non-aqueous electrolyte comprising an electrode group in which a positive electrode plate, a negative electrode plate, and a separator are stacked and accommodated in a rectangular battery case, and a positive electrode and a negative electrode terminal that are conductive from the electrode group and are fixed to the upper surface of the battery case In the battery, the battery case has a fragile portion that is cleaved at a predetermined internal pressure, and at least one of the fragile portions is formed on the upper surface of the battery case, and at least one of the fragile portions formed on the upper surface of the battery case. Is formed immediately above a blocking prevention member that is disposed inside the battery case and prevents the fragile part from being blocked when the fragile part is cleaved, and the blocking prevention member has one end at the negative electrode plate in the electrode group. A long conductive member having the other end connected to the negative electrode terminal, and the conductive member is insulated immediately above the conductive member and directly below the fragile portion, and twisted in the longitudinal direction of the conductive member. Placed at Scale member and, in the angular-shaped non-aqueous electrolyte batteries you characterized in that it is configured.

The battery module provided with the square nonaqueous electrolyte battery of any one of Claims 1 thru | or 3 .

In a battery module comprising a plurality of prismatic non-aqueous electrolyte batteries, each of the prismatic non-aqueous electrolyte batteries and a control circuit for controlling the entire prismatic non-aqueous electrolyte battery,
The rectangular non-aqueous electrolyte battery includes a positive electrode plate, a negative electrode plate, and a separator stacked in an electrode group housed in a rectangular battery case, and a positive electrode and a negative electrode terminal that are conductive from the electrode group and fixed on the upper surface of the battery case. The battery case has a fragile portion that is cleaved at a predetermined internal pressure, and at least one of the fragile portions is formed on the upper surface of the battery case,
Wherein the control circuit includes a battery module, wherein the outside directly above the at least one weak portion formed in the battery case upper surface, disposed on at least one of the upper surface of the respective battery case upper surface.

Wherein the control circuit, the battery module according to claim 5, wherein the through the control circuit protection member for protecting the control circuit is fixed to at least one of the upper surface of the respective battery case upper surface.

The battery module according to claim 6, wherein the control circuit protection member is a flame retardant ABS resin.