JP3643710B2

JP3643710B2 - Sealed alkaline storage battery and method for manufacturing the same

Info

Publication number: JP3643710B2
Application number: JP27107598A
Authority: JP
Inventors: 通則池添; 貴史小田; 英樹岡島
Original assignee: Sanyo Electric Co Ltd
Current assignee: Sanyo Electric Co Ltd
Priority date: 1998-09-25
Filing date: 1998-09-25
Publication date: 2005-04-27
Anticipated expiration: 2018-09-25
Also published as: JP2000100406A

Description

【０００１】
【発明の属する技術分野】
本発明は、電槽蓋に安全弁を設けてなる密閉型アルカリ蓄電池に関する。
【０００２】
【従来の技術】
ニッケル−水素電池やニッケル−カドミウム電池等の密閉型アルカリ蓄電池は、内圧が一定の圧力よりも高くなると開弁する安全弁を備えている。電池の内圧が異常に高くなったときに、電槽が破裂するのを防止するためである。密閉型アルカリ蓄電池は、充電するときの反応でガスが発生して、内部の圧力を上昇させる。その際、なんらかの原因で、内圧が異常に上昇することがある。このとき、ガスを外部に放出して、内部の圧力の上昇を阻止するのが安全弁である。さらに、安全弁は、正常な状態では、外気が電池の内部に侵入するのを阻止するシール性も要求される。
【０００３】
このような特性を満足させる安全弁は、電池の内圧が、２〜８ｋｇ／ｃｍ²よりも高くなると開弁してガスを排出する。開弁圧力が２ｋｇ／ｃｍ²よりも低いと、通常の充電状態において、安全弁が開放して電池を密閉化できなくなり、８ｋｇ／ｃｍ²以上でも開弁しないと、電槽が破裂する危険性があるからである。安全弁を一定の決められた圧力で開弁させるために、安全弁は、電池に固定する前に、作動圧を検査している。検査の結果、正常に作動する安全弁を電池の電槽に固定している。
【０００４】
密閉型アルカリ蓄電池は、安全弁を正確に作動させることに加えて、この安全弁を電槽に確実に固定することも大切である。安全弁を電槽に固定する構造として、安全弁の鍔部を、熱溶着して電槽蓋に固定する構造が、例えば、特開平１０−２１８９３号公報に記載される。
【０００５】
この公報に記載される密閉型アルカリ蓄電池は、安全弁の鍔部を加熱して溶着し、あるいは、安全弁を電槽蓋に押し付けて回転させることにより、摩擦熱で溶着している。この構造の密閉型アルカリ蓄電池は、安全弁を強固に電槽蓋に固定できる特長がある。しかしながら、この構造の電池は、安全弁を固定する前工程において、電池に圧力センサーを連結する検査工程を簡単に、しかも正確にするのが難しい欠点がある。この種の電池は、出荷前に、電池の極板を活性化し、あるいは、評価工程をするために、圧力センサーを連結する。圧力センサーが連結された電池は、充放電されて内圧力の変化を検出し、正常であるかどうかを判別している。この工程によって、不良電池を事前に検知している。
【０００６】
この検査工程は、安全弁を連結する前に行われる。不良電池を完成しないためである。圧力センサーは、安全弁と同じように、電槽蓋の取付穴に気密に連結して内圧を検出する必要がある。圧力センサーを取付穴に気密に連結するために、図１に示すように、Ｏリング１９を介して圧力センサー１７を取付穴４の開口部に押し付けている。しかしながら、この状態で圧力センサー１７を連結すると、圧力センサー１７と電槽蓋３との間を気密に連結するのが難しい。このため、検査工程で圧力センサー１７と電槽蓋３との間にガス漏れし、電池の内圧を正確に検出できない弊害がある。
【０００７】
【発明が解決しようとする課題】
この弊害は、安全弁を取付穴にねじ込んで連結する構造として解消できる。安全弁をねじ込んで連結する電池は、取付穴に雌ネジを設けているので、ここに圧力センサーをねじ込んで連結できるからである。しかしながら、この構造の密閉型アルカリ蓄電池は、圧力センサーを確実に気密に連結できるが、安全弁をねじ込んで固定するので、長期間にわたって確実に電槽蓋に連結できない。とくに、電池が振動を受けると、安全弁が緩んでしまう欠点がある。
【０００８】
したがって、従来の密閉型アルカリ蓄電池は、安全弁を電槽蓋に溶着して確実に固定できるものは、圧力センサーを簡単にしかもガス漏れしないように確実に連結することが難しく、また、安全弁をねじ込んで電槽蓋に連結する構造は、圧力センサーを確実に連結できる特長はあるが、振動すると安全弁が緩んでガス漏れする欠点があった。
【０００９】
本発明は、このような従来の欠点を解決することを目的に開発されたもので、安全弁を確実に電槽蓋に固定できることに加えて、圧力センサーを簡単に連結して能率よく試験できる密閉型アルカリ蓄電池を提供することにある。
【００１０】
【課題を解決するための手段】
本発明の密閉型アルカリ蓄電池は、正極と負極とがセパレータを介して積層されてなる発電要素群１と、この発電要素群１と電解液とを内蔵している電槽２と、この電槽２の開口部を閉塞している電槽蓋３と、電槽蓋３に設けられた取付穴４に連結されてなる安全弁５とを備える。さらに、密閉型アルカリ蓄電池は、取付穴４の内面に、圧力センサー１７を着脱自在にねじ込み可能な雌ネジ８を設けており、この取付穴４に安全弁５を挿入して溶着している。
【００１１】
さらに、本発明の請求項２に記載される密閉型アルカリ蓄電池は、安全弁５が、電槽蓋３に溶着される所定の厚さの鍔部９Ａと、電槽蓋３の取付穴４に挿入される挿入部９Ｂとを有する。さらに、電槽蓋３の取付穴４は、開口部に凹部７を有し、電槽蓋３の凹部７に鍔部９Ａの外周を溶着している。
【００１２】
さらに、本発明の請求項３に記載される密閉型アルカリ蓄電池は、安全弁５が、本体ケース９に、弁体１０と弾性体１１とを内蔵し、本体ケース９の開口部に蓋体１２を固定して組み立てている。
【００１３】
さらに、本発明の請求項４に記載される密閉型アルカリ蓄電池は、凹部７にＯリング１９を配置して、Ｏリング１９を介して圧力センサー１７を着脱自在にねじ込み可能となっている。
【００１４】
さらに、本発明の請求項５に記載される密閉型アルカリ蓄電池の製造方法は、正極と負極とがセパレータを介して積層されてなる発電要素群１と、この発電要素群１と電解液とを内蔵している電槽２と、この電槽２の開口部を閉塞している電槽蓋３と、電槽蓋３に設けた取付穴４に連結されてなる安全弁５とを備える密閉型アルカリ蓄電池の製造方法において、安全弁５を溶着する前に、取付穴４の雌ネジ８に圧力センサー１７をねじ込んで固定し、この状態で内圧の変化を検出して正常であるかどうかを判別し、不良電池を事前に検知して、正常な電池にのみ安全弁５を固定する。
【００１５】
さらに、本発明の請求項６に記載される密閉型アルカリ蓄電池の製造方法は、安全弁５は、本体ケース９に、弁体１０と弾性体１１とを内蔵し、本体ケース９の開口部に蓋体１２を固定して組み立て、安全弁５として正常に作動することを試験した後、電槽蓋３に溶着して固定する。
【００１７】
【発明の実施の形態】
以下、本発明の実施例を図面に基づいて説明する。ただし、以下に示す実施例は、本発明の技術思想を具体化するための密閉型アルカリ蓄電池を例示するものであって、本発明は密閉型アルカリ蓄電池を以下のものに特定しない。
【００１８】
さらに、この明細書は、特許請求の範囲を理解しやすいように、実施例に示される部材に対応する番号を、「特許請求の範囲の欄」、および「課題を解決するための手段の欄」に示される部材に付記している。ただ、特許請求の範囲に示される部材を、実施例の部材に特定するものでは決してない。
【００１９】
図２に示す密閉型アルカリ蓄電池は、正極と負極とがセパレータを介して積層されてなる発電要素群１と、この発電要素群１と電解液とを内蔵している電槽２と、この電槽２の開口部を閉塞している電槽蓋３と、電槽蓋３に設けた取付穴４に連結されてなる安全弁５とを備える。
【００２０】
この図の電池は、発電要素群１の正極と負極を、電槽蓋３に固定している＋−の電極端子６に内部で連結している。電極端子６は、電槽蓋３を気密に貫通して固定されている。発電要素群１は、密閉型アルカリ蓄電池のタイプによって異なる。密閉型アルカリ蓄電池がニッケル−水素電池の場合、負極には、パンチングメタルである芯体に、水素吸蔵合金を主体とした活物質を塗布した極板を使用し、正極には、多孔質ニッケルの芯体に、スラリー状の水酸化ニッケルを主体とした活物質を含浸して圧延した極板を使用する。複数枚の正極と複数枚の負極は、間にセパレータを介在させて絶縁して積層されて発電要素群１となる。
【００２１】
電槽２は、プラスチックを上方開口の箱型に成形したもので、開口部に電槽蓋３を気密に固定している。電槽蓋３は、接着あるいは溶着等の構造で、電槽２の開口部に固定される。
【００２２】
電槽蓋３は、図３の拡大断面図に示すように、安全弁５を連結する取付穴４を、中央部に貫通して開口している。取付穴４は、上端の開口部の内径を大きくして凹部７を設け、凹部７以外の部分の内面に雌ネジ８を設けている。凹部７は、外形を円形として底面を平滑な水平面としている。図示しないが、凹部の底面は、リング状に凸条を設け、この凸条を安全弁に溶着することもできる。
【００２３】
安全弁５は図３に示すように、本体ケース９と、この本体ケース９に内蔵される弁体１０と、弁体１０を弾性的に押圧する弾性体１１と、本体ケース９の上端開口部を閉塞している蓋体１２とを備える。本体ケース９は、電槽蓋３に溶着される鍔部９Ａと、電槽蓋３の取付穴４に挿入される挿入部９Ｂを有する。
【００２４】
本体ケース９は、鍔部９Ａを取付穴４の凹部７に溶着して安全弁５を電槽蓋３に固定する。鍔部９Ａは、外周を凹部７の内面に確実に溶着するために、その外形を円形とすると共に、外径を凹部７の内径よりも多少大きく形成している。図３に示すように、鍔部９Ａの外径と凹部７の内径との差（ｄ）は、たとえば０．１〜１ｍｍ、好ましくは０．１〜０．８ｍｍ、さらに好ましくは０．２〜０．５ｍｍとする。外径が凹部７の内径よりも大きい鍔部９Ａは、外周を溶融しながら凹部７に圧入されて、凹部７の内面に溶着される。
【００２５】
この状態で電槽蓋３に安全弁５を溶着する密閉型アルカリ蓄電池は、安全弁５と電槽蓋３とのガス漏れを極減して、しかも、安全弁５を強固に電槽蓋３に固定できる特長がある。安全弁５は、鍔部９Ａと凹部７の底面を溶着して電槽蓋３に固定することもできる。しかしながら、鍔部９Ａの底面を溶着して固定する安全弁５は、鍔部９Ａの外周を溶着する構造に比較して、電池の内圧で抜ける方向に移動しやすい。それは、電池に内圧が作用して、安全弁５が押し出されるとき、溶着面に引張力が作用するからである。鍔部９Ａの外周を凹部７の内面に溶着している安全弁５は、電池の内圧で抜ける方向に移動されるとき、溶着面を横ずれさせる方向に力が作用する。溶着面は、耐引張力に比較すると、横ずれする方向の移動を阻止しやすい。このため、鍔部９Ａの外周を凹部７の内面に溶着する安全弁５は、確実に外れないように電槽蓋３に固定できる特長がある。
【００２６】
鍔部９Ａを凹部７よりも大きくしている安全弁５は、溶融されない状態で、鍔部９Ａを凹部７に嵌入できない。このため、鍔部９Ａを凹部７の正確な位置に案内しながら挿入するのが難しい。図に示す密閉型アルカリ蓄電池は、取付穴４の内径と、安全弁５の挿入部９Ｂの外径をほぼ等しくして、挿入部９Ｂと取付穴４で、鍔部９Ａを凹部７の定位置に案内する。本明細書において、取付穴の内径とは、図３に示すように、ネジ山先端の内径、すなわち、取付穴４の最小の内径を意味するものとする。
【００２７】
挿入部９Ｂを取付穴４に挿入するとき、挿入部９Ｂの外周面は、取付穴４に設けた雌ネジ８の先端縁を摺動する。雌ネジ８の先端縁は螺旋状で、挿入部９Ｂを周囲から保持して、挿入部９Ｂを取付穴４の中心に案内する。さらに、雌ネジ８の先端縁で安全弁５の挿入部９Ｂを保持する構造は、たとえば、雌ネジ８の取付穴４の内径が、挿入部９Ｂの外径よりも多少大きくても、雌ネジ８のネジ山の先端部が変形して、挿入部９Ｂを取付穴４の中心に保持する。このため、挿入部９Ｂの外径と、取付穴４の内径を極めて高い精度で同じに直径に製造する必要がない。
【００２８】
圧力センサーをねじ込んで連結しない取付穴は、図示しないが、雌ネジのない平滑面とすることもできる。しかしながら、内面を平滑面とする取付穴で、挿入部を中心に保持する構造では、挿入部が取付穴よりも少しでも太いと、挿入部を取付穴に挿入できなくなる。実際の製造工程において、挿入部と取付穴の直径を正確に一致させることは極めて難しい。このため、取付穴に入れる挿入部は、取付穴よりも多少細く製造する必要がある。
【００２９】
これに対して、図３に示す、本発明の密閉型アルカリ蓄電池の電槽蓋３は、取付穴４に雌ネジ８を設けているので、取付穴４よりも太い挿入部９Ｂを入れると、雌ネジ８の先端縁が弾性変形して、挿入部９Ｂを取付穴４の中心に保持する。このため、たとえ挿入部９Ｂが取付穴４の内径よりも多少太くても、挿入部９Ｂを取付穴４の中心に正確に案内して挿入できる。したがって、取付穴４の雌ネジ８は、圧力センサーを簡単かつ容易に、しかも確実に連結できることに加えて、安全弁５の挿入部９Ｂを正確に中心に案内して挿入できる効果も実現する。
【００３０】
鍔部９Ａと挿入部９Ｂからなる本体ケース９は、挿入部９Ｂを筒状に成形して、挿入部９Ｂの底に弁孔１３を開口している。この弁孔１３の上方に弁体１０を配設している。弁体１０は、ゴム状弾性体の上部に硬質リング１４を連結している。ゴム状弾性体は、上面に中心に突出するロッドを有し、このロッドの周囲に硬質リング１４を配設している。硬質リング１４は、挿入部９Ｂに内蔵されるコイルスプリングの弾性体１１に押圧されて、ゴム状弾性体を弁孔１３に押し付けて安全弁５を閉弁させる。弾性体１１を押圧するために、挿入部９Ｂの上端対向部に蓋体１２を固定している。蓋体１２は、溶着され、あるい接着されて本体ケース９に固定される。蓋体１２は、開弁した弁孔１３を通過したガスを排出するガス抜孔１５を開口している。
【００３１】
安全弁５は、本体ケース９に、弁体１０と弾性体１１とを内蔵し、本体ケース９の開口部に蓋体１２を固定して組み立て、安全弁５として正常に作動することを試験した後、電槽蓋３に溶着して固定される。この安全弁５は、図４に示すように、本体ケース９の上面に超音波ホーン１６を押し付けて電槽蓋３に溶着される。超音波ホーン１６は、鍔部９Ａを超音波振動させて、鍔部９Ａと凹部７の接触部分を加熱溶融して、鍔部９Ａの外周を凹部７の内面に溶着する。さらに、超音波ホーン１６で押圧して、鍔部９Ａと凹部７の底面も溶着できる。
【００３２】
超音波溶着で電槽蓋３に溶着して製作される密閉型アルカリ蓄電池は、極めて短時間に安全弁５を確実に電槽蓋３に溶着できる特長がある。ただ、本発明の密閉型アルカリ蓄電池は、安全弁を高周波やヒータで加熱して電槽蓋に溶着し、さらに、安全弁を押圧する状態で回転させて摩擦熱で電槽蓋に溶着することもできる。
【００３３】
安全弁５と電槽蓋３は、熱で溶融されて互いに溶着される。このため、安全弁５と電槽蓋３は、少なくとも互いに溶着される部分を、熱可塑性のプラスチックで成形する。熱可塑性のプラスチックには、変成ＰＰＥ、ＰＰ、ＰＳ、ＰＰＥ／ＰＰアロイ等のプラスチックが使用できる。
【００３４】
密閉型アルカリ蓄電池は、安全弁５を溶着する前に、図５に示すように、取付穴４の雌ネジ８に圧力センサー１７をねじ込んで固定する。この状態で充放電して、内圧の変化を検出して、正常であるかどうかを判別し、不良電池を事前に検知して、正常な電池にのみ安全弁５を固定して完成させる。
【００３５】
［実施例］
図２に示す構造の密閉型アルカリ蓄電池を、以下のようにして製作した。この蓄電池は、容量を１００Ａｈとするニッケル−水素電池である。
▲１▼ ポリプロピレン製の角型電槽２に、発電要素群１を挿入し、電解液を注液して、電槽２の開口部を電槽蓋３で閉塞した。発電要素群１の正極と負極は、１００ｍｍ×１２０ｍｍの大きさとした。さらに、発電要素群１は、１７枚の正極と１８枚の負極を、セパレータを介して積層した。正極と負極は、ニッケル薄板を極板にスポット溶接し、正極、負極それぞれをまとめて、電極端子６にスポット溶接して集電した。電槽２に注液する電解液には、水酸化カリウム系電解液を使用した。
【００３６】
▲２▼ 電槽蓋３は、取付穴４にＭ１２の雌ネジ８を設け、ここに図５に示すように、圧力センサー１７をねじ込んで連結した。圧力センサー１７は、Ｍ１２の取付穴４に雌ネジ８にねじ込みできる、雄ネジ１８のあるものを使用した。圧力センサー１７を連結する状態で、＋−の電極端子６に充電用の電源を接続し、また放電用の負荷を交互に接続して、充放電させて内圧力の変化を検出して、正常であるかどうかを判別した。この工程で、不良電池を識別する。
【００３７】
▲３▼ 圧力センサー１７を取付穴４から外した後、取付穴４に安全弁５を超音波溶着して、電槽蓋３に固定した。安全弁５は、６ｋｇ／ｃｍ²で開弁するものを使用した。さらに、安全弁５は、鍔部９Ａを取付穴４の凹部７に溶着して電槽蓋３に固定した。安全弁５は、鍔部９Ａの外径を、凹部７の内径よりも０．３ｍｍ大きくして、鍔部９Ａの外周を凹部７の内面に溶着したものと、鍔部９Ａの外径と凹部７の内径を同じにして、鍔部９Ａと凹部７を底面で溶着したものを製作した。
【００３８】
以上の実施例で試作した密閉型アルカリ蓄電池は、圧力センサー１７をガス漏れしない状態で連結でき、しかも、極めて優れた耐震特性を示した。耐震性は、以下の条件で試験した。
振動する振動数を３３．３Ｈｚとし、加速度を５．５Ｇとした。この条件で、毎日、２時間連続して電池を加震した。その後、電槽蓋３を貫通して気密に空気管を連結し、空気管から電池内に６ｋｇ／ｃｍ²の加圧空気を圧入して加圧し、安全弁５と取付穴４の溶着部からのエアー漏れの有無を、リーク検査液を用いて確認した。
【００３９】
この振動条件において、実施例で試作した密閉型アルカリ蓄電池は、１カ月経過後も、安全弁５と電槽蓋３との間の空気漏れは発生しなかった。
【００４０】
比較のために、図６に示すうよに、Ｏリング１９を挟着して、安全弁５を取付穴４の雌ネジ８にねじ込む密閉型アルカリ蓄電池を試作した。この密閉型アルカリ蓄電池は、同じ耐震試験において、７日経過後に安全弁５と電槽蓋３との間で空気漏れが発生した。
【００４１】
【発明の効果】
本発明の密閉型アルカリ蓄電池は、安全弁を確実に電槽蓋に固定できることに加えて、圧力センサーを簡単に連結して能率よく試験できる特長がある。それは、本発明の密閉型アルカリ蓄電池が、電槽の開口部を閉塞している電槽蓋に設けられた取付穴の内面に雌ネジを設けており、この取付穴に安全弁を溶着しているからである。この密閉型アルカリ蓄電池は、電槽蓋の取付穴の内面に設けた雌ネジに圧力センサーをねじ込むことによって、簡単に、しかも、ガス漏れしないように確実に連結して能率よく試験できる。さらに、この密閉型アルカリ蓄電池は、電槽蓋の取付穴に安全弁を溶着して固定するので、安全弁を確実かつ強固に電槽蓋に固定できる。すなわち、本発明の密閉型アルカリ蓄電池は、極めて簡単な構造で、従来の密閉型アルカリ蓄電池の欠点であった、圧力センサーを簡単かつ確実に取付穴に連結し、安全弁を確実に電槽蓋に固定するという、互いに相反する両方の条件を同時に満たすことができる特長がある。
【図面の簡単な説明】
【図１】従来の密閉型アルカリ蓄電池の電槽蓋の取付穴に圧力センサーを連結する状態を示す断面図
【図２】本発明の実施例の密閉型アルカリ蓄電池の一部断面正面図
【図３】図２に示す密閉型アルカリ蓄電池の電槽蓋に安全弁を挿入する状態を示す拡大断面図
【図４】図３に示す安全弁を超音波ホーンで電槽蓋に溶着する状態を示す一部断面正面図
【図５】図２に示す密閉型アルカリ蓄電池の電槽蓋の取付穴に圧力センサーをねじ込んだ状態を示す断面図
【図６】比較例の密閉型アルカリ蓄電池の電槽蓋を示す断面図
【符号の説明】
１…発電要素群
２…電槽
３…電槽蓋
４…取付穴
５…安全弁
６…電極端子
７…凹部
８…雌ネジ
９…本体ケース９Ａ…鍔部９Ｂ…挿入部
１０…弁体
１１…弾性体
１２…蓋体
１３…弁孔
１４…硬質リング
１５…ガス抜孔
１６…超音波ホーン
１７…圧力センサー
１８…雄ネジ
１９…Ｏリング[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sealed alkaline storage battery in which a safety valve is provided on a battery case lid.
[0002]
[Prior art]
Sealed alkaline storage batteries such as nickel-hydrogen batteries and nickel-cadmium batteries have a safety valve that opens when the internal pressure becomes higher than a certain pressure. This is to prevent the battery case from rupturing when the internal pressure of the battery becomes abnormally high. In a sealed alkaline storage battery, gas is generated by a reaction when charging, and the internal pressure is increased. At that time, the internal pressure may rise abnormally for some reason. At this time, the safety valve releases the gas to the outside and prevents the internal pressure from increasing. Furthermore, the safety valve is required to have a sealing property that prevents outside air from entering the inside of the battery in a normal state.
[0003]
A safety valve that satisfies such characteristics opens and discharges gas when the internal pressure of the battery is higher than ² to 8 kg / cm ² . If the valve opening pressure is lower than 2 kg / cm ² , the safety valve opens in the normal charging state and the battery cannot be sealed, and if it does not open even at 8 kg / cm ² or more, there is a risk that the battery case may burst. Because there is. In order to open the safety valve at a fixed pressure, the safety valve checks the operating pressure before being secured to the battery. As a result of the inspection, a normally operating safety valve is fixed to the battery case.
[0004]
In addition to operating the safety valve accurately, it is also important for the sealed alkaline storage battery to securely fix the safety valve to the battery case. As a structure for fixing the safety valve to the battery case, a structure in which the collar portion of the safety valve is thermally welded and fixed to the battery case cover is described in, for example, Japanese Patent Application Laid-Open No. 10-21893.
[0005]
The sealed alkaline storage battery described in this publication is welded by frictional heat by heating and welding the collar portion of the safety valve, or by pressing the safety valve against the battery lid and rotating it. The sealed alkaline storage battery having this structure has a feature that the safety valve can be firmly fixed to the battery case lid. However, the battery with this structure has a drawback that it is difficult to easily and accurately perform the inspection process for connecting the pressure sensor to the battery in the previous process of fixing the safety valve. This type of battery is connected to a pressure sensor in order to activate the battery electrode plate or perform an evaluation process before shipment. The battery connected to the pressure sensor is charged / discharged to detect a change in internal pressure, and determines whether or not it is normal. By this process, a defective battery is detected in advance.
[0006]
This inspection process is performed before connecting the safety valve. This is because a defective battery is not completed. Like the safety valve, the pressure sensor needs to detect the internal pressure by airtightly connecting to the mounting hole of the battery case lid. In order to airtightly connect the pressure sensor to the mounting hole, the pressure sensor 17 is pressed against the opening of the mounting hole 4 through the O-ring 19 as shown in FIG. However, if the pressure sensor 17 is connected in this state, it is difficult to connect the pressure sensor 17 and the battery case lid 3 in an airtight manner. For this reason, gas leaks between the pressure sensor 17 and the battery case lid 3 in the inspection process, and there is a problem that the internal pressure of the battery cannot be accurately detected.
[0007]
[Problems to be solved by the invention]
This adverse effect can be solved by a structure in which the safety valve is screwed into the mounting hole and connected. This is because the battery to which the safety valve is screwed and connected is provided with a female screw in the mounting hole, so that the pressure sensor can be screwed and connected here. However, the sealed alkaline storage battery having this structure can reliably connect the pressure sensor in an airtight manner, but cannot be reliably connected to the battery case cover for a long time because the safety valve is screwed and fixed. In particular, there is a drawback that the safety valve loosens when the battery is vibrated.
[0008]
Therefore, the conventional sealed alkaline storage battery that can be securely fixed by welding the safety valve to the battery case lid is difficult to connect the pressure sensor easily and securely so that no gas leaks. The structure connected to the battery case lid has the feature that the pressure sensor can be securely connected, but has the disadvantage that the safety valve loosens and leaks when vibrated.
[0009]
The present invention was developed for the purpose of solving such conventional drawbacks, and in addition to being able to securely fix the safety valve to the battery case lid, the pressure sensor can be easily connected and sealed for efficient testing. It is to provide a type alkaline storage battery.
[0010]
[Means for Solving the Problems]
A sealed alkaline storage battery according to the present invention includes a power generation element group 1 in which a positive electrode and a negative electrode are laminated via a separator, a battery case 2 containing the power generation element group 1 and an electrolyte, and the battery case. 2, and a safety valve 5 connected to a mounting hole 4 provided in the battery case lid 3. Further, the sealed alkaline storage battery is provided with a female screw 8 into which the pressure sensor 17 can be removably screwed on the inner surface of the mounting hole 4, and the safety valve 5 is inserted into the mounting hole 4 and welded.
[0011]
Further, in the sealed alkaline storage battery according to claim 2 of the present invention, the safety valve 5 is inserted into the flange portion 9A having a predetermined thickness welded to the battery case lid 3 and the mounting hole 4 of the battery case lid 3. And an insertion portion 9B. Further, the mounting hole 4 of the battery case lid 3 has a recess 7 in the opening, and the outer periphery of the flange portion 9 A is welded to the recess 7 of the battery case lid 3.
[0012]
Further, in the sealed alkaline storage battery according to claim 3 of the present invention, the safety valve 5 has the valve body 10 and the elastic body 11 built in the main body case 9, and the lid body 12 is provided at the opening of the main body case 9. Fixed and assembled.
[0013]
Further, in the sealed alkaline storage battery described in claim 4 of the present invention, an O-ring 19 is disposed in the recess 7 and the pressure sensor 17 can be detachably screwed through the O-ring 19.
[0014]
Furthermore, in the method for producing a sealed alkaline storage battery according to claim 5 of the present invention, a power generation element group 1 in which a positive electrode and a negative electrode are laminated via a separator, and the power generation element group 1 and an electrolyte solution are provided. A sealed alkali comprising a built-in battery case 2, a battery case lid 3 closing the opening of the battery case 2, and a safety valve 5 connected to a mounting hole 4 provided in the battery case cover 3. In the method for manufacturing a storage battery, before welding the safety valve 5, the pressure sensor 17 is screwed and fixed to the female screw 8 of the mounting hole 4, and in this state, a change in internal pressure is detected to determine whether it is normal, A defective battery is detected in advance, and the safety valve 5 is fixed only to a normal battery.
[0015]
Furthermore, in the method for producing a sealed alkaline storage battery according to claim 6 of the present invention, the safety valve 5 has the main body case 9 with the valve body 10 and the elastic body 11 built therein, and the opening of the main body case 9 has a lid. After the body 12 is fixed and assembled and tested to operate normally as the safety valve 5, it is welded and fixed to the battery case lid 3.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. However, the Example shown below illustrates the sealed alkaline storage battery for embodying the technical idea of the present invention, and the present invention does not specify the sealed alkaline storage battery as follows.
[0018]
Further, in this specification, in order to facilitate understanding of the scope of claims, the numbers corresponding to the members shown in the examples are referred to as “the scope of claims” and “the means for solving the problems”. It is added to the member shown by. However, the members shown in the claims are not limited to the members in the embodiments.
[0019]
The sealed alkaline storage battery shown in FIG. 2 includes a power generation element group 1 in which a positive electrode and a negative electrode are stacked with a separator interposed therebetween, a battery case 2 containing the power generation element group 1 and an electrolyte, A battery case lid 3 that closes the opening of the tank 2 and a safety valve 5 connected to a mounting hole 4 provided in the battery case lid 3 are provided.
[0020]
In the battery of this figure, the positive electrode and the negative electrode of the power generation element group 1 are internally connected to a +-electrode terminal 6 fixed to the battery case lid 3. The electrode terminal 6 penetrates the battery case lid 3 in an airtight manner and is fixed. The power generation element group 1 differs depending on the type of sealed alkaline storage battery. When the sealed alkaline storage battery is a nickel-hydrogen battery, the negative electrode uses an electrode plate in which an active material mainly composed of a hydrogen storage alloy is applied to a core that is a punching metal, and the positive electrode is made of porous nickel. An electrode plate rolled by impregnating an active material mainly composed of slurry-like nickel hydroxide into a core is used. The plurality of positive electrodes and the plurality of negative electrodes are insulated and laminated with a separator interposed therebetween to form the power generation element group 1.
[0021]
The battery case 2 is formed of plastic in a box shape with an upper opening, and a battery case lid 3 is airtightly fixed to the opening. The battery case lid 3 is fixed to the opening of the battery case 2 with a structure such as adhesion or welding.
[0022]
As shown in the enlarged cross-sectional view of FIG. 3, the battery case lid 3 has an attachment hole 4 for connecting the safety valve 5 penetrating through the central portion and opening. The mounting hole 4 is provided with a recess 7 by increasing the inner diameter of the opening at the upper end, and a female screw 8 is provided on the inner surface of the portion other than the recess 7. The concave portion 7 has a circular outer shape and a smooth horizontal bottom surface. Although not shown, the bottom surface of the recess can be provided with a ridge in a ring shape, and the ridge can be welded to the safety valve.
[0023]
As shown in FIG. 3, the safety valve 5 includes a main body case 9, a valve body 10 incorporated in the main body case 9, an elastic body 11 that elastically presses the valve body 10, and an upper end opening of the main body case 9. And a lid 12 that is closed. The main body case 9 has a flange portion 9 A welded to the battery case lid 3 and an insertion portion 9 B inserted into the attachment hole 4 of the battery case lid 3.
[0024]
The body case 9 fixes the safety valve 5 to the battery case lid 3 by welding the flange 9 A to the recess 7 of the mounting hole 4. The flange portion 9 A has a circular outer shape and a slightly larger outer diameter than the inner diameter of the concave portion 7 in order to reliably weld the outer periphery to the inner surface of the concave portion 7. As shown in FIG. 3, the difference (d) between the outer diameter of the flange 9A and the inner diameter of the recess 7 is, for example, 0.1 to 1 mm, preferably 0.1 to 0.8 mm, and more preferably 0.2 to 0.5 mm. The flange portion 9 A whose outer diameter is larger than the inner diameter of the concave portion 7 is press-fitted into the concave portion 7 while melting the outer periphery, and is welded to the inner surface of the concave portion 7.
[0025]
The sealed alkaline storage battery in which the safety valve 5 is welded to the battery case lid 3 in this state can minimize the gas leakage between the safety valve 5 and the battery case lid 3 and can firmly fix the safety valve 5 to the battery case lid 3. There are features. The safety valve 5 can also be fixed to the battery case lid 3 by welding the bottom surface of the flange 9A and the recess 7. However, the safety valve 5 that welds and fixes the bottom surface of the flange portion 9A is more likely to move in the direction in which it is removed by the internal pressure of the battery, compared to a structure in which the outer periphery of the flange portion 9A is welded. This is because when the internal pressure acts on the battery and the safety valve 5 is pushed out, a tensile force acts on the welding surface. When the safety valve 5 that welds the outer periphery of the flange portion 9A to the inner surface of the recess 7 is moved in a direction that is released by the internal pressure of the battery, a force acts in a direction that laterally shifts the welding surface. The welding surface tends to prevent movement in the direction of lateral displacement compared to the tensile strength. For this reason, the safety valve 5 which welds the outer periphery of the collar part 9A to the inner surface of the recessed part 7 has an advantage that it can be fixed to the battery case lid 3 so as not to be surely removed.
[0026]
The safety valve 5 having the flange portion 9A larger than the recess portion 7 cannot fit the flange portion 9A into the recess portion 7 without being melted. For this reason, it is difficult to insert the collar portion 9 A while guiding the collar portion 9 A to the accurate position of the recess 7. In the sealed alkaline storage battery shown in the figure, the inner diameter of the mounting hole 4 is substantially equal to the outer diameter of the insertion portion 9B of the safety valve 5, and the flange portion 9A is placed at a fixed position of the recess 7 by the insertion portion 9B and the mounting hole 4. invite. In the present specification, the inner diameter of the mounting hole means the inner diameter of the thread tip, that is, the minimum inner diameter of the mounting hole 4 as shown in FIG.
[0027]
When inserting the insertion portion 9 B into the attachment hole 4, the outer peripheral surface of the insertion portion 9 B slides on the tip edge of the female screw 8 provided in the attachment hole 4. The leading edge of the female screw 8 is spiral, and the insertion portion 9B is held from the periphery to guide the insertion portion 9B to the center of the mounting hole 4. Further, the structure in which the insertion portion 9B of the safety valve 5 is held at the tip edge of the female screw 8 is, for example, even if the inner diameter of the mounting hole 4 of the female screw 8 is slightly larger than the outer diameter of the insertion portion 9B. The tip of the thread is deformed to hold the insertion portion 9B at the center of the mounting hole 4. For this reason, it is not necessary to manufacture the outer diameter of the insertion portion 9B and the inner diameter of the mounting hole 4 to the same diameter with extremely high accuracy.
[0028]
Although not shown in the drawing, the mounting hole in which the pressure sensor is not screwed and connected may be a smooth surface without a female screw. However, in the structure in which the inner surface is held by the mounting hole having a smooth inner surface, the insertion portion cannot be inserted into the mounting hole if the insertion portion is slightly thicker than the mounting hole. In an actual manufacturing process, it is extremely difficult to accurately match the diameters of the insertion portion and the mounting hole. For this reason, it is necessary to manufacture the insertion part put in a mounting hole somewhat thinner than a mounting hole.
[0029]
On the other hand, since the battery case lid 3 of the sealed alkaline storage battery of the present invention shown in FIG. 3 is provided with the female screw 8 in the mounting hole 4, when the insertion portion 9B thicker than the mounting hole 4 is inserted, The leading edge of the female screw 8 is elastically deformed to hold the insertion portion 9B at the center of the mounting hole 4. For this reason, even if the insertion portion 9B is somewhat thicker than the inner diameter of the attachment hole 4, the insertion portion 9B can be accurately guided and inserted into the center of the attachment hole 4. Therefore, the female screw 8 of the mounting hole 4 realizes an effect that the pressure sensor can be easily and reliably connected, and that the insertion portion 9B of the safety valve 5 can be accurately guided and inserted.
[0030]
In the main body case 9 including the flange portion 9A and the insertion portion 9B, the insertion portion 9B is formed into a cylindrical shape, and a valve hole 13 is opened at the bottom of the insertion portion 9B. The valve body 10 is disposed above the valve hole 13. The valve body 10 has a hard ring 14 connected to the upper part of a rubber-like elastic body. The rubber-like elastic body has a rod protruding from the center on the upper surface, and a hard ring 14 is disposed around the rod. The hard ring 14 is pressed by the elastic body 11 of the coil spring built in the insertion portion 9B, and presses the rubber-like elastic body against the valve hole 13 to close the safety valve 5. In order to press the elastic body 11, the lid body 12 is fixed to the upper end facing portion of the insertion portion 9B. The lid body 12 is welded or bonded and fixed to the main body case 9. The lid 12 has a gas vent hole 15 for discharging the gas that has passed through the valve hole 13 that has been opened.
[0031]
After the safety valve 5 incorporates the valve body 10 and the elastic body 11 in the main body case 9, the lid body 12 is fixed to the opening of the main body case 9 and assembled, and it is tested that the safety valve 5 operates normally. It is welded and fixed to the battery case lid 3. As shown in FIG. 4, the safety valve 5 is welded to the battery case lid 3 by pressing an ultrasonic horn 16 against the upper surface of the main body case 9. The ultrasonic horn 16 ultrasonically vibrates the flange portion 9A, heats and melts the contact portion between the flange portion 9A and the concave portion 7, and welds the outer periphery of the flange portion 9A to the inner surface of the concave portion 7. Further, the bottom surface of the flange 9A and the recess 7 can be welded by pressing with the ultrasonic horn 16.
[0032]
The sealed alkaline storage battery manufactured by welding to the battery case lid 3 by ultrasonic welding has a feature that the safety valve 5 can be reliably welded to the battery case lid 3 in an extremely short time. However, the sealed alkaline storage battery of the present invention can be welded to the battery case lid by heating the safety valve with a high frequency or a heater, and further rotating while the safety valve is pressed to be welded to the battery case lid by frictional heat. .
[0033]
The safety valve 5 and the battery case lid 3 are melted by heat and welded to each other. For this reason, the safety valve 5 and the battery case lid 3 are formed of a thermoplastic plastic at least at a portion to be welded to each other. Plastics such as modified PPE, PP, PS, and PPE / PP alloy can be used as the thermoplastic plastic.
[0034]
In the sealed alkaline storage battery, before welding the safety valve 5, as shown in FIG. 5, the pressure sensor 17 is screwed into the female screw 8 of the mounting hole 4 and fixed. In this state, charging / discharging is performed, a change in internal pressure is detected, it is determined whether or not it is normal, a defective battery is detected in advance, and the safety valve 5 is fixed only to a normal battery and completed.
[0035]
[Example]
A sealed alkaline storage battery having the structure shown in FIG. 2 was produced as follows. This storage battery is a nickel-hydrogen battery having a capacity of 100 Ah.
{Circle around (1)} The power generation element group 1 was inserted into a rectangular battery case 2 made of polypropylene, the electrolyte was injected, and the opening of the battery case 2 was closed with the battery case lid 3. The positive electrode and the negative electrode of the power generation element group 1 were 100 mm × 120 mm in size. Furthermore, in the power generation element group 1, 17 positive electrodes and 18 negative electrodes were laminated via a separator. The positive electrode and the negative electrode were collected by spot welding a nickel thin plate to the electrode plate, collecting the positive electrode and the negative electrode together, and spot welding the electrode terminal 6. A potassium hydroxide electrolyte was used as the electrolyte to be poured into the battery case 2.
[0036]
{Circle around (2)} The battery case lid 3 was provided with M12 female screws 8 in the mounting holes 4 and connected thereto by screwing a pressure sensor 17 as shown in FIG. As the pressure sensor 17, a sensor having a male screw 18 that can be screwed into the female screw 8 in the mounting hole 4 of M 12 was used. In a state where the pressure sensor 17 is connected, a power source for charging is connected to the +-electrode terminal 6 and a load for discharging is alternately connected to charge and discharge to detect a change in internal pressure. It was determined whether or not. In this step, a defective battery is identified.
[0037]
(3) After removing the pressure sensor 17 from the mounting hole 4, the safety valve 5 was ultrasonically welded to the mounting hole 4 and fixed to the battery case lid 3. A safety valve 5 that opens at 6 kg / cm ² was used. Furthermore, the safety valve 5 was fixed to the battery case lid 3 by welding the flange 9 A to the recess 7 of the mounting hole 4. The safety valve 5 has an outer diameter of the flange portion 9A larger by 0.3 mm than an inner diameter of the recess portion 7, the outer periphery of the flange portion 9A is welded to the inner surface of the recess portion 7, and the outer diameter and the recess portion 7 of the flange portion 9A. The same inner diameter was prepared, and the flange portion 9A and the concave portion 7 were welded on the bottom surface.
[0038]
The sealed alkaline storage battery prototyped in the above example can be connected to the pressure sensor 17 without causing gas leakage, and exhibits extremely excellent earthquake resistance. The earthquake resistance was tested under the following conditions.
The vibration frequency was 33.3 Hz, and the acceleration was 5.5 G. Under this condition, the battery was vibrated continuously for 2 hours every day. Thereafter, an air pipe is connected through the battery case lid 3 in an airtight manner, 6 kg / cm ² of pressurized air is press-fitted into the battery from the air pipe and pressurized, and the safety valve 5 and the mounting hole 4 are connected from the welded portion. The presence or absence of air leakage was confirmed using a leak test solution.
[0039]
Under this vibration condition, the sealed alkaline storage battery prototyped in the example did not leak air between the safety valve 5 and the battery case lid 3 even after one month had passed.
[0040]
For comparison, as shown in FIG. 6, a sealed alkaline storage battery in which an O-ring 19 is sandwiched and the safety valve 5 is screwed into the female screw 8 of the mounting hole 4 was made as a prototype. In this sealed alkaline storage battery, air leakage occurred between the safety valve 5 and the battery case lid 3 after 7 days in the same earthquake resistance test.
[0041]
【The invention's effect】
The sealed alkaline storage battery of the present invention has an advantage that it can be efficiently tested by simply connecting a pressure sensor in addition to being able to securely fix the safety valve to the battery case lid. In the sealed alkaline storage battery of the present invention, a female screw is provided on the inner surface of a mounting hole provided in the battery case lid that closes the opening of the battery case, and a safety valve is welded to the mounting hole. Because. This sealed alkaline storage battery can be easily and efficiently tested by screwing a pressure sensor into a female screw provided in the inner surface of the mounting hole of the battery case lid, and securely and securely without gas leakage. Furthermore, since this sealed alkaline storage battery has the safety valve welded and fixed to the mounting hole of the battery case lid, the safety valve can be fixed to the battery case lid reliably and firmly. In other words, the sealed alkaline storage battery of the present invention has a very simple structure, and has been a drawback of the conventional sealed alkaline storage battery. The pressure sensor is simply and reliably connected to the mounting hole, and the safety valve is securely connected to the battery case lid. It has the feature that it can satisfy both mutually contradictory conditions of fixing at the same time.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a state in which a pressure sensor is connected to a mounting hole of a battery case lid of a conventional sealed alkaline storage battery. FIG. 2 is a partially sectional front view of a sealed alkaline storage battery according to an embodiment of the present invention. 3 is an enlarged cross-sectional view showing a state where the safety valve is inserted into the battery case lid of the sealed alkaline storage battery shown in FIG. 2. FIG. 4 is a partial view showing a state where the safety valve shown in FIG. 3 is welded to the battery case lid with an ultrasonic horn. FIG. 5 is a sectional view showing a state in which a pressure sensor is screwed into the mounting hole of the battery case lid of the sealed alkaline storage battery shown in FIG. 2. FIG. Sectional view [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Electric power generation element group 2 ... Battery case 3 ... Battery case cover 4 ... Mounting hole 5 ... Safety valve 6 ... Electrode terminal 7 ... Recessed part 8 ... Female screw 9 ... Main body case 9A ... Gutter 9B ... Insertion part 10 ... Valve body 11 ... Elastic body 12 ... Lid 13 ... Valve hole 14 ... Hard ring 15 ... Gas vent hole 16 ... Ultrasonic horn 17 ... Pressure sensor 18 ... Male screw 19 ... O-ring

Claims

A power generation element group (1) in which a positive electrode and a negative electrode are laminated via a separator, a battery case (2) containing the power generation element group (1) and an electrolyte, and the battery case (2) In a sealed alkaline storage battery comprising a battery case lid (3) closing the opening of the battery and a safety valve (5) connected to a mounting hole (4) provided in the battery case lid (3) A female screw (8) to which the pressure sensor (17) can be removably screwed is provided on the inner surface of (4), and a safety valve (5) is inserted into the mounting hole (4) and welded. A sealed alkaline storage battery.

A safety valve (5) is welded to the battery case lid (3) with a flange (9A) having a predetermined thickness, and an insertion part (9B) is inserted into the mounting hole (4) of the battery case lid (3). The mounting hole (4) of the battery case lid (3) has a recess (7) in the opening, and the outer periphery of the flange (9A) is welded to the recess (7) of the battery case lid (3). A sealed alkaline storage battery according to claim 1.

The safety valve (5) is assembled by incorporating the valve body (10) and the elastic body (11) in the main body case (9) and fixing the lid (12) to the opening of the main body case (9). A sealed alkaline storage battery according to claim 1 .

The sealed alkaline storage battery according to claim 2, wherein an O-ring (19) is arranged in the recess (7), and the pressure sensor (17) can be detachably screwed through the O-ring (19) .

A power generation element group (1) in which a positive electrode and a negative electrode are laminated via a separator, a battery case (2) containing the power generation element group (1) and an electrolyte, and the battery case (2) In the manufacturing method of a sealed alkaline storage battery comprising a battery case lid (3) closing the opening of the battery case and a safety valve (5) connected to a mounting hole (4) provided in the battery case lid (3) Before welding the safety valve (5), the pressure sensor (17) is screwed into the female screw (8) of the mounting hole (4) and fixed. In this state, the change of the internal pressure is detected to determine whether it is normal. A method for producing a sealed alkaline storage battery, characterized in that a defective battery is detected in advance and the safety valve (5) is fixed only to a normal battery.

The safety valve (5) is assembled by fixing the valve body (10) and the elastic body (11) in the main body case (9), and fixing the lid (12) to the opening of the main body case (9). (5) The manufacturing method of the sealed alkaline storage battery according to claim 5, wherein the sealed alkaline storage battery is fixed by being welded to the battery case lid (3) after being tested for normal operation.