JP4048031B2

JP4048031B2 - Sealed electricity storage device

Info

Publication number: JP4048031B2
Application number: JP2001093101A
Authority: JP
Inventors: 浩幸紙透; 利彦西山; 学原田; 雅人黒崎; 裕二中川; 知希信田; 勝哉三谷
Original assignee: NEC Tokin Corp
Current assignee: Tokin Corp
Priority date: 2001-03-28
Filing date: 2001-03-28
Publication date: 2008-02-13
Anticipated expiration: 2021-03-28
Also published as: JP2002289172A

Description

【０００１】
【発明の属する技術分野】
本発明は密閉式蓄電デバイスに関し、特に密閉式蓄電デバイスの封止栓の構造に関するものである。
【０００２】
【従来の技術】
近年、情報通信の分野では携帯機器の小型化・軽量化が進んでおり、これに対応して小型化・軽量化且つ急速充放電可能な二次電池や電気二重層コンデンサ等の蓄電デバイスの開発が盛んに行われ、ニッケル―水素電池、ニッケル―カドミウム電池といったアルカリ電池やリチウムイオン電池をはじめとする密閉式の蓄電デバイスが広く実用化されている。
【０００３】
密閉式の蓄電デバイスは、携帯機器に搭載するにあたり、スペース効率の点で優れているが、電気化学的反応に伴う発生ガスにより、デバイスの内圧が異常に上昇した場合、デバイスセルの破裂や封止孔の開放によるデバイス構体の破壊が生じる危険性がある。このため多くの密閉式の蓄電デバイスでは、ある程度の内圧に達した場合、発生ガスを外部へ開放させ破壊を未然に防止する防爆安全機構を備えている。
【０００４】
特開２０００―２６８８１１号公報には、外装缶の封口蓋に設けられた電解液の注液孔に単一組成のゴムで一体成形した弾性体を圧入し、この弾性体を覆うように支持部材で弾性体を固定させて密閉した電池が開示されている。この技術では、電池内部にガスが発生して電池の内圧が上昇した場合には、上記弾性体が変形し、注入孔との間に隙間をつくって、電池内部のガスを電池外部に放出させ、電池破壊を防止する。
【０００５】
また、特開平５―１９０１６４号公報には、電池ケースの開口部を封口蓋と環状ガスケットで封口した密閉式アルカリ電池が開示されている。封口蓋には弁孔と排気孔が設けられており、この弁孔が変形能の大きいゴムと変形能の小さいゴムを一体化積層した弾性体で閉塞されることによって電池内部が密閉される。電池の内部にガス等が発生して電池内部圧力が増加すると弾性体が変形し、弁孔からガス等が逸散して内部圧力が減少して電池破壊が防止される。この技術では、変形能の大きいゴムによって作動圧力の調整を行うようにしたため、防爆に対する作動圧力のばらつきを小さくなり、防爆安全性が向上する。
【０００６】
【発明が解決しようとする課題】
しかしながら、これらの技術においては、電池の内部ガスの圧力調整の機能は、単にゴムの弾性だけでなく、弾性体を固定する支持部材により大きな影響をうける。つまり、支持部材が弾性体を固定する圧力が下がれば、作動圧力は低下する。この支持部材が弾性体を固定する圧力は支持部材の固定状態により大きく変化し、その制御の精度を高めることはかなり困難である。これらの理由から、上記の従来の密閉式電池では、防爆安全性に対して十分とはいえなかった。
【０００７】
従って、本発明の目的は、これらの点を鑑み、弾性体自体のみの弁機能により、内部発生ガスに対する内圧制御を精度よく行える密閉式蓄電デバイス用の封止栓とそれを用い、高い防爆安全性を備えた密閉式蓄電デバイスを提供することにある。
【０００８】
【課題を解決するための手段】
本発明の封止栓は、密閉式蓄電デバイスのガスケットに設けられた円柱状の注液孔に装着され、該蓄電デバイス内部を封止する封止栓において、板状の支持体と、該支持体に接続され、前記注液孔に挿入される封止弁とを備え、前記封止弁が前記支持体に接続された弁軸部と、該弁軸部に接続され、前記挿入される方向に狭まる円錐台状の弾性を有する弁部とを備えていることを特徴とする。
【０００９】
前記弁部の材料としてＥＰＤＭ（エチレンとプロピレンと非共役ジエン化合物との三元共重合体）等のゴム材が使用される。該弁部の表面をフッ素樹脂で被覆することによって弁部の撥水性が向上し、封止栓の封止性能が向上できる。
【００１０】
前記支持体としては、弁部のゴム材よりも硬度の大きなゴム材または金属板が使用される。
【００１１】
前記封止弁の前記弁軸部には金属棒を挿入して弁軸部の機械的強度を上げることができる。また、前記弁部の上端面の前記弁軸部の境界と前記弁部縁との間にリング状に溝を形成しておき、密閉式蓄電デバイスの注液孔に装着した場合、該デバイス内部の圧力増加で内側方向へ変形をしやすくすることができる。
【００１２】
上記の本発明の封止栓を密閉式蓄電デバイスに使用する場合には、封止栓の弁部上端部外形直径は、蓄電デバイスの注液孔の口径の１．１〜１．３倍が適当である。封止栓の支持体は蓄電デバイスのガスケットにその端部をシリコーン樹脂またはエポキシ樹脂等の接着剤で固定される。ガスケットには、封止栓の支持体を装着する凹部を設けることもでき、該凹部に支持体を装着することによって支持体の固定が容易となる。
【００１３】
本発明では、封止栓自身が弁作用を有するため、弁作動圧力を任意かつ精度よく調節でき、ガス発生により蓄電デバイスの内圧が上昇した際の防爆安全性が向上する。また、本封止栓は、蓄電デバイス内部のガスをデバイス外部に放出して内圧が低下したときは、弁部（弾性体）が元の状態に復帰して、再び密閉状態が維持されるので、ガス漏れや液漏れを生じることなく、本来の充放電機能を支障なく発揮することができる。
【００１４】
【発明の実施の形態】
次に、本発明の実施の形態について図面を参照して説明する。図１は、本発明の実施の形態の封止栓の構造示す斜視図である。図１を参照すると、本実施の形態の封止栓５０は、板状の支持体１と、その支持体１に接続された封止弁３を備えて構成されている。封止弁３は、支持体１に接続された弁軸部２ａと、弁軸部２ａに接続され、挿入方向に狭まる円錐台状の弁部２とを備えている。弁軸部２ａの形状は円柱または角柱である。
【００１５】
封止弁３は弾性を有するゴム材からなる。ゴム材の種類は問わないが、電池等の蓄電デバイスに使用される電解液に対して、耐性の高いものを使用する。例えば、ゴム材としては、ＥＰＤＭ等が使用できる。弁軸部２ａと弁部２のゴム材は同じでも異なってもよいが、異なる場合には、弁部２のゴム材の硬さを弁軸部２ａよりも小さくする。ゴム材の硬さは使用に際しての内部圧力の値に応じて適宜選択できるが、通常ゴム硬さが２０〜６０程度のゴムが使用される。支持体１は弁部２よりも硬さの大きいゴム材からなる。弁軸部２ａと弁部２のゴム材の材料が異なる場合には、支持体１と弁軸部２ａのゴム材は同じものを使用してもよい。支持体１のゴム材も使用する電解液に対して耐性の高いものが望ましい。なお、封止弁の弁部２には、撥水性を有するフッ素系の樹脂をコーティングすることができる。これにより、封止栓を通じて電解液の蒸発が抑えられ、電解液揮発による容量異常の発生が低減される効果がある。
【００１６】
また、支持体１は蓄電デバイスのガスケットと接着剤により固着させるため、対接着性の高いものが望ましいといえる。なお、支持体１の材質をゴム材としたが、それなり硬さをもち、電解液に対する耐性の高いものならば、金属材料等他の材料でもかまわない。
【００１７】
封止弁３の弁部２の構造は挿入方向に狭まった円錐台の形状にしてある。弁部をこのような構造にすることにより、密閉式の蓄電デバイスの封止栓に使用した場合に、蓄電デバイスの内部圧力が規定よりも大きな値になった場合に、内方に弾性変形して内部のガス等を効率よく開放して内部圧力を下げることができる。
【００１８】
封止栓の構造としては、図２のような構造も考えることができる。図２（ａ）は弁軸部２ａの内部に金属棒２０を挿入して弁軸部の機械的強度を補強した場合であり、図２（ｂ）は弁部２上面の弁軸部２ａとの境界に隣接した箇所にリング状に溝３０を設け、弁部２を弁軸方向の内方に変形しやすくした場合である。また、図２（ｃ）は、図２（ａ）と図２（ｂ）を組み合わせた場合である。図２（ａ）や図２（ｃ）の場合には、支持体１に金属棒の２０上端部をネジ止めすることによって、支持体１への封止弁３の固定が容易となる。なお、図２（ｂ）において、弁部上面の溝３０の設ける位置は、弁軸部との境界から弁部２の外周端の間であればどこでもよい。
【００１９】
なお、図１を参照すると、支持体１の形状は矩形板状であるが、この形状は矩形板状に限定されず、三角形以上の多角形板や円板状等であってもよい。
【００２０】
次に、上記の本発明の封止栓を使用した密閉式の蓄電デバイスの実施の形態について図面を参照して説明する。
【００２１】
図３は、本発明の封止栓を使用した第１の実施の形態の密閉式蓄電デバイスの封止部の図で、（ａ）は平面図、（ｂ）は（ａ）のＡ―Ａ’線に断面図である。蓄電デバイスとしては密閉式二次電池（例えばポリマー二次電池）を使用した。
【００２２】
ガスケット４に円柱状の注液孔６が設けられており、この注液孔６から電解液を注入した後、この注液孔６に封止栓５０の封止弁３を挿入し、支持体１を接着剤でガスケット４の表面に固定して電池が封止される。支持体１の幅は図３（ａ）のように、注液孔６の口径よりも小さくしてあり、電池内部から開放されたガスを外部に放出できるようになっている。なお、密閉式二次電池の内部には電極およびセパレータからなる電池素子が設置されているが図３では表示していない。
【００２３】
注液孔６の口径は電池体の大きさにより異なるが、おおよそ直径１．０ｍｍ〜１．５ｍｍの範囲である。封止栓５０の弁部２の径は、ゴムの硬さと必要とされる弁作動圧力により決定されるが、注液孔６の口径のおおよそ１．１〜１．３倍の範囲である。弁部２の直径が注液孔６の口径の１．１倍よりも小さくなると封止性が低下する。これが１．３倍を超えると電池の内部圧力が大きくなった場合でも内部圧力に対する弁部２の変形圧力よりも弁部２の注液孔６壁の押圧力が大きいために電池内部ガスを外部に開放できない。電池内部のガスが開放され、電池内部の圧力が減少すると弁部２は弾性によって元の封止状態にもどる。
【００２４】
接着剤５はガスケット４と封止栓５０の支持体１固定させるもので、ゴム材に対して接着性のよいものを使用する。通常、シリコーン樹脂系、およびエポキシ樹脂系の接着剤が用いられる。
【００２５】
図４は、本発明の封止栓を使用した第２の実施の形態の密閉式蓄電デバイスの封止部の図で、（ａ）は平面図、（ｂ）は（ａ）のＡ―Ａ’線に断面図である。この場合も蓄電デバイスとしては密閉式二次電池を使用した。
【００２６】
本電池では、図４（ｂ）のように、ガスケット４に封止栓の支持体１も装填できる凹部４０を設け、この４０の底部から注液孔６が設けられている。このような封止栓挿入部の構造によって、図３よりも封止栓のガスケット４への固定が容易となる。
【００２７】
図５は、本発明の封止栓を使用した第３の実施の形態の密閉式蓄電デバイスの封止部の図で、（ａ）は平面図、（ｂ）は（ａ）のＡ―Ａ’線に沿った断面図、（ｃ）は（ａ）のＢ―Ｂ’線に沿った断面図である。この場合も蓄電デバイスとしては密閉式二次電池を使用した。
【００２８】
本電池では、図５（ａ）のように、図３の封止栓の支持体１の幅を注液孔６の口径よりも大きくした場合である。この場合、支持体１のガスケット４の接触面には電池内部から開放されたガスを放出する排気溝７を設ける。この構造では図３と比較して、支持体の機械的強度が増加する。排気溝７の代わりに支持体１に注液孔が露出するように切欠き部を設けてもよい。
【００２９】
図６は、本発明の封止栓を使用した第４の実施の形態の密閉式蓄電デバイスの封止部の図で、（ａ）は平面図、（ｂ）は（ａ）のＡ―Ａ’線に沿った断面図、（ｃ）は（ａ）のＢ―Ｂ’線に沿った断面図である。この場合も蓄電デバイスとしては密閉式二次電池を使用した。
【００３０】
本電池は、図４の封止栓の支持体１の幅を注液孔６の口径よりも大きくした場合である。この場合、支持体１には電池内部から開放されたガスを放出する排気用切欠き部８を設ける。この構造では図４と比較して、支持体の機械的強度が増加し、また、図５よりも封止栓のガスケット４への固定が容易となる。
【００３１】
なお、上記の図３〜図６の封止栓としては、図１の構造のものを使用したが、図２の構造の封止栓も使用することができる。また、図３〜図６の封止構造は、電気二重層コンデンサにも適用できることはいうまでもない。
【００３２】
以下、図１の封止栓を使用した二次電池および電気二重層コンデンについて実施例に基づいてより具体的に説明する。なお、封止構造は図３の構造を適用した。
【００３３】
（実施例１）
以下のように、密閉式二次電池（ポリマー電池）を製造した。
【００３４】
電池素子となる正極には活物質としてＰＣＩ（ポリシアノインドール）、負極の活物質としてＰＱｘ（ポリキノキサリン）を使用し、それぞれ導電補助材であるカ−ボン粉末を２０％程度混合し、高速攪拌機にて攪拌した。この粉末を２００℃の高温にて加圧成型したものを電極として使用した。
【００３５】
次に、この電極の正極と負極の間にオレフィン系の多孔膜をセパレータとしてはさみ、あらかじめ所定の大きさに加工した、未加硫のゴムからなるガスケットの中に入れ、両側を厚さ２００μｍの未加硫の導電性ゴムではさみ、２ｋｇｆ／ｃｍ²の加圧をかけ、恒温槽にて１２０℃で２時間放置して電池セルを作製した。このセルのガスケットに直径１．０ｍｍの注液孔を開け、電解液を注入した。電解液は４０ｗｔ％硫酸水溶液を使用した。注液の完了した電池セルの両端に金属端子板を取り付けポリマー電池を作製した。封止は本発明の支持体がゴム硬さ９０のＳＢＲ、封止弁がゴム硬さ５０のＥＰＤＭからなる封止栓を使用し、支持体の両端をエポキシ樹脂にて接着することによって行った。尚本封止弁の径は注入孔の１．１倍のものを使用した。
【００３６】
上記の工程で製造したポリマー電池を１００個を６０℃の恒温槽中で定格電圧の１．１倍まで１Ｃで定電流充電を行ったのち、定格電圧の０．８倍まで１クーロンで定電流放電を行うことを１サイクルとするサイクル試験にかけた。この試験を１０００サイクル行った。そのときの放電容量を測定し初期容量に対する変化率を調査し、変化率が１０％以上変化した電池を容量変化異常として、その個数を計測した。また同時に、そのときの電池の１ｋＨｚでのＥＳＲ（等価直列抵抗）を測定し、初期ＥＳＲに対する変化率を調査し、変化率が５０％以上変化した電池をＥＳＲ変化異常として、その個数を計測した。同時にまた１０００サイクル時の外観状態（液漏れ、セル破裂、集電体亀裂など）を調査した。
【００３７】
本実施例では、容量変化異常数１個、ＥＳＲ変化異常数１個、外観異常数０個であった。
【００３８】
上記実施例の動作で述べた試験を実施すると、高温で電池の過充電が繰り返されるため、電池内部でのガス発生により、セルの内圧が徐々に上昇する。セル内部のガス抜けが正常に行われなかった場合は、セルの内圧が異常に高くなり、導電端子との接触抵抗が高くなるため電池のＥＳＲが上昇する。また、内圧が高くなりすぎた場合、セルの破裂や集電体の亀裂による液漏れなどが発生する。また、逆にセル内部のガス抜けが容易に起こる状態であった場合は、電解液の揮発が進み、電池の容量が低下する。このため、セルのガス抜けに関しては適度な範囲が要求される。
【００３９】
実施例に使用した封止栓は、ゴム材質と硬さを最適に選択したため、精度よくガス抜き動作が起こり、安定した電池特性が得られた。
【００４０】
（実施例２）
封止栓に、支持体にゴム硬さ１００のＥＰＤＭ、封止弁にゴム硬さ５０のＥＰＤＭをからなる封止栓を用いた他は、実施例１と同じ構成をもつポリマー電池を作製し、実施例１と同様のサイクル試験を行い評価した。
その結果、容量変化異常数０個、ＥＳＲ変化異常数１個、外観異常数０個であった。
【００４１】
本実施例では、支持体と封止弁に同様のゴム種を使用したが、支持体によりガスケットと封止栓が、しっかり固定されていれば、ガス抜き機能自体は封止弁の弁が有するため、実施例１と同様、精度よくガス抜き動作が起こり、安定した電池特性が得られたといえる。
【００４２】
（実施例３）
電極に活性炭を使用し、セパレータを挟んで一対の活性炭電極を配置し、さらに活性炭電極の両側に集電体を配置してコンデンサ素子を構成した。封止栓に支持体にゴム硬さ９０のＥＰＤＭ、封止弁にゴム硬さ３５のＥＰＤＭをからなる封止栓を用いた他は、実施例１と同じ封止構造をもつ電気二重層コンデンサを作製し、実施例１と同様のサイクル試験を行い評価した。なお、電解液には硫酸水溶液を使用した。
【００４３】
その結果、容量変化異常数０個、ＥＳＲ変化異常数３個、外観異常数０個であった。
【００４４】
本実施例では、電極に活性炭を使用する電気二重層コンデンサに、本発明の封止栓を使用したが、電気二重層コンデンサはＥＳＲの値が低く、少しのガス発生による内圧上昇がＥＳＲ値に敏感に影響される。このため、封止弁のゴム硬度を３５に変更して適用したところ、実施例１と同様、精度よくガス抜き動作が起こり、安定した電池特性が得られた。このように本発明では、封止弁自体に動作圧力を制御する機能をもつ弁を有しているため、ゴム硬度の変更等により容易に動作圧力制御ができる利点がある。
【００４５】
（実施例４）
封止栓に、弁部の径が注入孔の口径の１．１５倍であり、封止弁にゴム硬さ４０のＥＰＤＭをからなる封止栓を用いた他は、実施例１と同じ構成をもつポリマー電池を作製し、実施例１と同様のサイクル試験を行い評価した。その結果、容量変化異常数０個、ＥＳＲ変化異常数１個、外観異常数０個であった。
【００４６】
本実施例では、封止栓の弁径を変更している。弁径をやや大きくした分、封止弁のゴム硬度を下げ、最適化を図った。これにより実施例１と同様、精度よくガス抜き動作が起こり、安定した電池特性が得られた。このように本発明の封止栓では、単にゴム硬度だけでなく、弁の径を変更することにより、容易に動作圧力制御ができる利点がある。
【００４７】
（実施例５）
封止栓に、封止弁にフッ素樹脂をコーティングした他は、実施例１と同じ構成をもつポリマー電池を作製し、実施例１と同様のサイクル試験を行い評価した。その結果、容量変化異常数０個、ＥＳＲ変化異常数０個、外観異常数０個であった。なお、フッ素樹脂のコーティング厚さは約２０μｍとした。
【００４８】
本実施例では、封止栓に撥水性を有するフッ素系の樹脂をコーティングしている。これにより、封止栓を通じて電解液の蒸発が抑えられ、電解液揮発による容量異常の発生が低減する効果が見込まれる。このように本発明では、封止弁自体に表面処理により、特別の効果をもたらすことができる利点がある。
【００４９】
（実施例６）
封止栓に、弁の径が注入孔の口径の１．１５倍であり、封止弁にゴム硬さ３０のＥＰＤＭをからなる封止栓を用いた他は、実施例３と同じ封止構造をもつ電気二重層コンデンサを作製し、実施例１と同様のサイクル試験を行い評価した。その結果、容量変化異常数０個、ＥＳＲ変化異常数１個、外観異常数０個であった。
【００５０】
本実施例では、実施例３と同様、電極に活性炭を使用する電気二重層コンデンサに、本発明の封止栓を使用したが、少しのガス発生による内圧上昇がＥＳＲ値に敏感に影響される電気二重層コンデンサに対し、ゴム硬度、弁径の両面から圧力制御ができる本封止弁の利点を生かし最適化した結果、実施例１と同様、精度よくガス抜き動作が起こり、安定した電気二重層コンデンサの容量特性が得られた。
【００５１】
（比較例１）
従来の封止栓を使用した密閉式電池の構成は以下の通りである。図７に従来の封止栓を使用した電池の構造を示す。図７は、封止栓１１が支持板１０が接着剤１３で固定されることにより、ガスケット１２に設けられた注液孔１４を塞いでいる部分を示す。この封止栓１１は弾性を有するゴム材よりなっている。支持板１０は封止栓１１を固定するために使用されるもので、それ自体が変形しにくいプラスチックおよび金属材料のものが使用される。これらの封止構造以外の構成は、上記の本発明の実施例１に示したものと同様である。
【００５２】
実施例１と同様のサイクル試験を行い評価した。その結果、容量変化異常数５個、ＥＳＲ変化異常数１６個、外観異常数７個であった。
【００５３】
本比較例１は、特性異常が多かったが、これは次の理由によるものと考えられる。本比較例１の封止構造は、封止栓を支持板で固定する方法をとっているが、これは内圧上昇によるガス抜けの制御が、封止栓のもつ弾性だけで決まらず、封止栓を固定する状態によって変化するためである。つまり、支持板の接着状態により、支持板が封止栓を抑える圧力が弱くなると、栓の作動圧力は低くなり、反対に支持板の封止栓を抑える圧力が高くなると、栓の作動圧力は高くなる。ゴムの弾性は、ほぼそのゴム材によって決まり、大きく違わないが、支持板が封止栓を抑える圧力は、制御が難しくばらつきが大きくなる。このため電池の内圧制御のばらつきが大きくなったため、サイクルでの電池特性が安定しなかったといえる。
【００５４】
（比較例２）
電極に活性炭を使用した他は、比較例１と同じ構成を持つ電気二重層コンデンサを作製し、実施例１と同様のサイクル試験を行い評価した。その結果、容量変化異常数４個、ＥＳＲ変化異常数２８個、外観異常数９個であった。
【００５５】
本比較例２は、少しのガス発生による内圧上昇がＥＳＲ値に敏感に影響される電気二重層コンデンサであったため、内圧制御のばらつきの影響を大きく受け、比較例１より異常が多くなっている。
【００５６】
表１に上記の本発明の実施例と比較例の蓄電デバイスの評価結果をまとめて示す。
【００５７】
【表１】

【００５８】
【発明の効果】
以上説明したように、本発明の封止栓は、弾性を有し、注液孔への注入方向に狭まった円錐台状の弁部を有しており、これを密閉式蓄電デバイスの封止栓に使用した場合には、次のような効果がある。
（１）封止栓として自身が弁作用を有するため、弁作動圧力を任意かつ精度よく調節でき、ガス発生により蓄電デバイスの内圧が上昇した際の防爆安全性を向上できる。
（２）また、本封止栓は、蓄電デバイス内部のガスをデバイス外部に放出して内圧が低下したときは、弁部（弾性体）が元の状態に復帰して、再び密閉状態が維持されるので、ガス漏れや液漏れを生じることなく、本来の充放電機能を支障なく発揮することができる。
【図面の簡単な説明】
【図１】本発明の実施の形態の封止栓の構造示す斜視図である。
【図２】本発明の封止栓のその他の構造例を示す断面図である。
【図３】本発明の封止栓を使用した第１の実施の形態の密閉式蓄電デバイスの封止部の図で、（ａ）は平面図、（ｂ）は（ａ）のＡ―Ａ’線に断面図である。
【図４】本発明の封止栓を使用した第２の実施の形態の密閉式蓄電デバイスの封止部の図で、（ａ）は平面図、（ｂ）は（ａ）のＡ―Ａ’線に断面図である。
【図５】本発明の封止栓を使用した第３の実施の形態の密閉式蓄電デバイスの封止部の図で、（ａ）は平面図、（ｂ）は（ａ）のＡ―Ａ’線に沿った断面図、（ｃ）は（ａ）のＢ―Ｂ’線に沿った断面図である。
【図６】本発明の封止栓を使用した第４の実施の形態の密閉式蓄電デバイスの封止部の図で、（ａ）は平面図、（ｂ）は（ａ）のＡ―Ａ’線に沿った断面図、（ｃ）は（ａ）のＢ―Ｂ’線に沿った断面図である。
【図７】従来の封止栓を使用した電池の構造を示す断面図である。
【符号の説明】
１支持体
２弁部
２ａ弁軸部
３封止弁
４，１２ガスケット
５，１３接着剤
６，１４注液孔
７排気溝
８排気用切欠き部
１０支持板
１１，５０封止栓
２０金属棒
３０溝
４０凹部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sealed electric storage device, and particularly to a structure of a sealing plug of the sealed electric storage device.
[0002]
[Prior art]
In recent years, mobile devices have become smaller and lighter in the field of information and communications, and in response to this, development of power storage devices such as secondary batteries and electric double layer capacitors that can be reduced in size and weight and can be rapidly charged and discharged. Enclosed storage devices such as alkaline batteries such as nickel-hydrogen batteries and nickel-cadmium batteries and lithium ion batteries have been widely put into practical use.
[0003]
A sealed electricity storage device is superior in space efficiency when mounted on a portable device, but if the internal pressure of the device rises abnormally due to gas generated by an electrochemical reaction, the device cell may burst or be sealed. There is a risk of destruction of the device structure due to the opening of the blind hole. For this reason, many sealed electric storage devices are provided with an explosion-proof safety mechanism that releases generated gas to the outside and prevents destruction before reaching a certain internal pressure.
[0004]
In Japanese Patent Laid-Open No. 2000-268811, an elastic body integrally molded with a single composition rubber is press-fitted into an electrolyte solution injection hole provided in a sealing lid of an outer can, and a support member is covered so as to cover the elastic body Discloses a battery in which an elastic body is fixed and sealed. In this technology, when gas is generated inside the battery and the internal pressure of the battery rises, the elastic body deforms, creating a gap between the injection hole and releasing the gas inside the battery to the outside of the battery. Prevents battery destruction.
[0005]
Japanese Patent Laid-Open No. 5-190164 discloses a sealed alkaline battery in which the opening of a battery case is sealed with a sealing lid and an annular gasket. The sealing lid is provided with a valve hole and an exhaust hole, and the inside of the battery is sealed by closing the valve hole with an elastic body integrally laminated with a rubber having a large deformability and a rubber having a small deformability. When gas or the like is generated inside the battery and the battery internal pressure is increased, the elastic body is deformed, and the gas or the like is diffused from the valve hole and the internal pressure is reduced to prevent battery destruction. In this technique, since the operating pressure is adjusted by rubber having a large deformability, the variation in the operating pressure with respect to the explosion-proof is reduced, and the explosion-proof safety is improved.
[0006]
[Problems to be solved by the invention]
However, in these technologies, the function of adjusting the pressure of the internal gas of the battery is greatly influenced not only by the elasticity of rubber but also by the support member that fixes the elastic body. That is, if the pressure at which the support member fixes the elastic body decreases, the operating pressure decreases. The pressure at which the support member fixes the elastic body varies greatly depending on the fixed state of the support member, and it is quite difficult to increase the accuracy of the control. For these reasons, the above-described conventional sealed battery is not sufficient for explosion-proof safety.
[0007]
Therefore, in view of these points, the object of the present invention is to provide a sealing plug for a sealed electricity storage device that can accurately control the internal pressure with respect to the internally generated gas by using only the valve function of the elastic body itself, and a high explosion-proof safety using the same. Another object of the present invention is to provide a sealed electric storage device having the characteristics.
[0008]
[Means for Solving the Problems]
The sealing plug of the present invention is mounted in a cylindrical liquid injection hole provided in a gasket of a sealed electricity storage device, and seals the inside of the electricity storage device. A valve connected to the body and inserted into the liquid injection hole, the valve shaft connected to the support, and the direction in which the valve is connected and inserted And a valve portion having a truncated cone-like elasticity that narrows.
[0009]
A rubber material such as EPDM (a terpolymer of ethylene, propylene and a non-conjugated diene compound) is used as the material of the valve portion. By covering the surface of the valve portion with a fluororesin, the water repellency of the valve portion is improved, and the sealing performance of the sealing plug can be improved.
[0010]
As the support, a rubber material or a metal plate having a hardness higher than that of the valve portion is used.
[0011]
A metal rod can be inserted into the valve stem portion of the sealing valve to increase the mechanical strength of the valve stem portion. In addition, when a groove is formed in a ring shape between a boundary of the valve shaft portion on the upper end surface of the valve portion and the edge of the valve portion and the groove is attached to the liquid injection hole of the sealed electric storage device, It is possible to easily deform inward by increasing the pressure.
[0012]
When the sealing plug of the present invention is used in a sealed electric storage device, the outer diameter of the valve portion upper end portion of the sealing plug is 1.1 to 1.3 times the diameter of the liquid injection hole of the electric storage device. Is appropriate. The end of the support of the sealing plug is fixed to the gasket of the electricity storage device with an adhesive such as silicone resin or epoxy resin. The gasket may be provided with a recess for mounting the support of the sealing plug, and the support can be easily fixed by mounting the support in the recess.
[0013]
In the present invention, since the sealing plug itself has a valve action, the valve operating pressure can be adjusted arbitrarily and accurately, and the explosion-proof safety when the internal pressure of the electricity storage device increases due to gas generation is improved. In addition, when the internal pressure is reduced by releasing the gas inside the electricity storage device to the outside of the device, this sealing plug returns to its original state and the sealed state is maintained again. The original charge / discharge function can be exhibited without hindrance without causing gas leakage or liquid leakage.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a structure of a sealing plug according to an embodiment of the present invention. Referring to FIG. 1, a sealing plug 50 according to the present embodiment includes a plate-like support 1 and a sealing valve 3 connected to the support 1. The sealing valve 3 includes a valve shaft portion 2a connected to the support 1, and a truncated cone-shaped valve portion 2 connected to the valve shaft portion 2a and narrowing in the insertion direction. The shape of the valve stem 2a is a cylinder or a prism.
[0015]
The sealing valve 3 is made of an elastic rubber material. Although the kind of rubber material is not ask | required, a thing with high tolerance is used with respect to the electrolyte solution used for electrical storage devices, such as a battery. For example, EPDM can be used as the rubber material. The rubber material of the valve shaft portion 2a and the valve portion 2 may be the same or different, but in such a case, the hardness of the rubber material of the valve portion 2 is made smaller than that of the valve shaft portion 2a. The hardness of the rubber material can be appropriately selected according to the value of the internal pressure at the time of use, but usually rubber having a rubber hardness of about 20 to 60 is used. The support 1 is made of a rubber material that is harder than the valve portion 2. When the rubber material of the valve shaft part 2a and the valve part 2 is different, the same rubber material may be used for the support 1 and the valve shaft part 2a. It is desirable that the rubber material of the support 1 is highly resistant to the electrolyte used. The valve portion 2 of the sealing valve can be coated with a fluorine-based resin having water repellency. Thereby, the evaporation of the electrolytic solution is suppressed through the sealing plug, and there is an effect that the occurrence of the capacity abnormality due to the evaporation of the electrolytic solution is reduced.
[0016]
Further, since the support 1 is fixed by a gasket and an adhesive of the electricity storage device, it can be said that a material having high adhesiveness is desirable. In addition, although the material of the support body 1 is a rubber material, other materials such as a metal material may be used as long as it has a certain hardness and has a high resistance to the electrolytic solution.
[0017]
The structure of the valve portion 2 of the sealing valve 3 has a truncated cone shape narrowed in the insertion direction. By using such a structure for the valve portion, when used as a sealing plug for a sealed electricity storage device, if the internal pressure of the electricity storage device becomes larger than the specified value, it will elastically deform inward. The internal gas can be efficiently released to lower the internal pressure.
[0018]
As the structure of the sealing plug, a structure as shown in FIG. 2 can be considered. FIG. 2A shows a case where the metal rod 20 is inserted into the valve shaft portion 2a to reinforce the mechanical strength of the valve shaft portion. FIG. 2B shows the valve shaft portion 2a on the upper surface of the valve portion 2. This is a case in which a groove 30 is provided in a ring shape at a location adjacent to the boundary of the valve portion 2 so that the valve portion 2 is easily deformed inward in the valve shaft direction. FIG. 2C shows the case where FIG. 2A and FIG. 2B are combined. In the case of FIG. 2A and FIG. 2C, fixing the sealing valve 3 to the support 1 is facilitated by screwing the upper end portion of the metal rod 20 to the support 1. In addition, in FIG.2 (b), the position in which the groove | channel 30 of a valve part upper surface is provided may be anywhere between the boundary with a valve shaft part and the outer peripheral end of the valve part 2.
[0019]
Referring to FIG. 1, the shape of the support 1 is a rectangular plate shape, but this shape is not limited to the rectangular plate shape, and may be a polygonal plate or a disc shape having a triangular shape or more.
[0020]
Next, an embodiment of a sealed electricity storage device using the sealing plug of the present invention will be described with reference to the drawings.
[0021]
FIGS. 3A and 3B are diagrams of a sealing portion of the hermetic power storage device according to the first embodiment using the sealing plug of the present invention, in which FIG. 3A is a plan view and FIG. 'Is a cross-sectional view along the line. As the electricity storage device, a sealed secondary battery (for example, a polymer secondary battery) was used.
[0022]
A cylindrical liquid injection hole 6 is provided in the gasket 4, and after injecting an electrolytic solution from the liquid injection hole 6, the sealing valve 3 of the sealing plug 50 is inserted into the liquid injection hole 6, and the support body The battery is sealed by fixing 1 to the surface of the gasket 4 with an adhesive. As shown in FIG. 3A, the width of the support 1 is smaller than the diameter of the liquid injection hole 6 so that the gas released from the inside of the battery can be discharged to the outside. In addition, although the battery element which consists of an electrode and a separator is installed in the inside of a sealing type secondary battery, it is not displaying in FIG.
[0023]
The diameter of the liquid injection hole 6 varies depending on the size of the battery body, but is approximately in the range of 1.0 mm to 1.5 mm in diameter. The diameter of the valve portion 2 of the sealing plug 50 is determined by the hardness of the rubber and the required valve operating pressure, but is approximately 1.1 to 1.3 times the diameter of the liquid injection hole 6. When the diameter of the valve part 2 is smaller than 1.1 times the diameter of the liquid injection hole 6, the sealing performance is lowered. If this exceeds 1.3 times, even if the internal pressure of the battery increases, the pressure inside the injection hole 6 of the valve section 2 is greater than the deformation pressure of the valve section 2 with respect to the internal pressure. Cannot be opened. When the gas inside the battery is released and the pressure inside the battery decreases, the valve portion 2 returns to its original sealed state due to elasticity.
[0024]
The adhesive 5 is used to fix the support 4 of the gasket 4 and the sealing plug 50, and an adhesive having good adhesion to the rubber material is used. Usually, silicone resin-based and epoxy resin-based adhesives are used.
[0025]
4A and 4B are diagrams of a sealing portion of a hermetic electricity storage device according to a second embodiment using the sealing plug of the present invention, in which FIG. 4A is a plan view and FIG. 4B is AA of FIG. 'Is a cross-sectional view along the line. Also in this case, a sealed secondary battery was used as the electricity storage device.
[0026]
In this battery, as shown in FIG. 4B, the gasket 4 is provided with a recess 40 in which the support 1 of the sealing plug can be loaded, and a liquid injection hole 6 is provided from the bottom of the 40. Such a structure of the sealing plug insertion portion makes it easier to fix the sealing plug to the gasket 4 than in FIG.
[0027]
FIGS. 5A and 5B are diagrams of a sealing part of a sealed electric storage device according to a third embodiment using the sealing plug of the present invention, in which FIG. 5A is a plan view and FIG. (C) is a cross-sectional view taken along line BB 'in (a). Also in this case, a sealed secondary battery was used as the electricity storage device.
[0028]
In this battery, as shown in FIG. 5A, the width of the support 1 of the sealing plug of FIG. 3 is larger than the diameter of the liquid injection hole 6. In this case, an exhaust groove 7 for releasing gas released from the inside of the battery is provided on the contact surface of the gasket 4 of the support 1. In this structure, the mechanical strength of the support is increased as compared with FIG. You may provide a notch so that a liquid injection hole may be exposed to the support body 1 instead of the exhaust groove 7. FIG.
[0029]
FIGS. 6A and 6B are diagrams of a sealing portion of a sealed electric storage device according to a fourth embodiment using the sealing plug of the present invention, in which FIG. 6A is a plan view and FIG. (C) is a cross-sectional view taken along line BB 'in (a). Also in this case, a sealed secondary battery was used as the electricity storage device.
[0030]
This battery is a case where the width of the support 1 of the sealing plug of FIG. 4 is made larger than the diameter of the liquid injection hole 6. In this case, the support 1 is provided with an exhaust notch 8 for releasing the gas released from the inside of the battery. In this structure, the mechanical strength of the support is increased as compared with FIG. 4, and the sealing plug can be more easily fixed to the gasket 4 than in FIG.
[0031]
In addition, although the thing of the structure of FIG. 1 was used as said sealing stopper of FIGS. 3-6, the sealing stopper of the structure of FIG. 2 can also be used. Moreover, it cannot be overemphasized that the sealing structure of FIGS. 3-6 is applicable also to an electrical double layer capacitor.
[0032]
Hereinafter, the secondary battery and the electric double layer condenser using the sealing plug of FIG. 1 will be described more specifically based on examples. In addition, the structure of FIG. 3 was applied for the sealing structure.
[0033]
Example 1
A sealed secondary battery (polymer battery) was produced as follows.
[0034]
The positive electrode used as the battery element uses PCI (polycyanoindole) as an active material and PQx (polyquinoxaline) as an active material for the negative electrode. Was stirred. A powder obtained by press molding this powder at a high temperature of 200 ° C. was used as an electrode.
[0035]
Next, an olefin-based porous film is sandwiched between the positive electrode and the negative electrode of this electrode as a separator and put into a gasket made of unvulcanized rubber that has been processed to a predetermined size in advance, and both sides have a thickness of 200 μm. A battery cell was fabricated by sandwiching with unvulcanized conductive rubber and applying a pressure of ² kgf / cm ² and leaving it in a constant temperature bath at 120 ° C. for 2 hours. An injection hole having a diameter of 1.0 mm was formed in the gasket of the cell, and an electrolytic solution was injected. The electrolytic solution used was a 40 wt% aqueous sulfuric acid solution. A metal terminal plate was attached to both ends of the battery cell where the injection was completed to prepare a polymer battery. Sealing was performed by using a sealing plug made of SBR having a rubber hardness of 90 for the support of the present invention and EPDM having a rubber hardness of 50 for the sealing valve, and bonding both ends of the support with an epoxy resin. . The diameter of this sealing valve was 1.1 times that of the injection hole.
[0036]
100 polymer batteries manufactured in the above process were charged at a constant current of 1C up to 1.1 times the rated voltage in a constant temperature bath at 60 ° C, and then at a constant current of 1 coulomb up to 0.8 times the rated voltage. A cycle test was conducted in which discharging was one cycle. This test was performed 1000 cycles. The discharge capacity at that time was measured, the rate of change with respect to the initial capacity was investigated, and the number of batteries with the rate of change changed by 10% or more was regarded as abnormal capacity change. At the same time, the ESR (equivalent series resistance) at 1 kHz of the battery at that time was measured, the rate of change with respect to the initial ESR was investigated, and the number of cells with the rate of change changed by 50% or more was determined as an ESR change abnormality. . At the same time, the appearance state at 1000 cycles (liquid leakage, cell rupture, current collector crack, etc.) was investigated.
[0037]
In this example, the number of abnormalities in capacity change was 1, the number of abnormalities in ESR change was 1, and the number of abnormalities in appearance was 0.
[0038]
When the test described in the operation of the above embodiment is performed, the battery is repeatedly overcharged at a high temperature, so that the internal pressure of the cell gradually increases due to gas generation inside the battery. When the gas escape from the inside of the cell is not normally performed, the internal pressure of the cell becomes abnormally high and the contact resistance with the conductive terminal becomes high, so that the ESR of the battery rises. If the internal pressure becomes too high, cell rupture or liquid leakage due to current collector cracks may occur. On the other hand, when the gas inside the cell easily escapes, the volatilization of the electrolyte proceeds and the battery capacity decreases. For this reason, an appropriate range is required for outgassing of the cell.
[0039]
The sealing plugs used in the examples selected the rubber material and hardness optimally, so that the degassing operation occurred with high accuracy and stable battery characteristics were obtained.
[0040]
(Example 2)
A polymer battery having the same configuration as in Example 1 was prepared except that the sealing plug was made of EPDM having a rubber hardness of 100 for the support and EPDM having a rubber hardness of 50 for the sealing valve. The same cycle test as in Example 1 was performed for evaluation.
As a result, the capacity change abnormality number was 0, the ESR change abnormality number was 1, and the appearance abnormality number was 0.
[0041]
In this example, the same rubber type was used for the support and the sealing valve. However, if the gasket and the sealing plug are firmly fixed by the support, the gas venting function itself has the valve of the sealing valve. Therefore, it can be said that, as in Example 1, the degassing operation occurred with high accuracy and stable battery characteristics were obtained.
[0042]
(Example 3)
Activated carbon was used as an electrode, a pair of activated carbon electrodes were disposed with a separator in between, and a current collector was disposed on both sides of the activated carbon electrode to constitute a capacitor element. The electric double layer capacitor having the same sealing structure as in Example 1 except that the sealing plug is made of EPDM having a rubber hardness of 90 for the support and the sealing valve is made of EPDM having a rubber hardness of 35 for the sealing valve. The same cycle test as in Example 1 was performed and evaluated. A sulfuric acid aqueous solution was used as the electrolyte.
[0043]
As a result, the capacity change abnormality number was 0, the ESR change abnormality number was 3, and the appearance abnormality number was 0.
[0044]
In this example, the sealing plug of the present invention was used for an electric double layer capacitor that uses activated carbon as an electrode. However, the electric double layer capacitor has a low ESR value, and a slight increase in internal pressure due to gas generation becomes an ESR value. Sensitively affected. For this reason, when the rubber hardness of the sealing valve was changed to 35 and applied, the degassing operation occurred with high accuracy as in Example 1, and stable battery characteristics were obtained. As described above, in the present invention, since the sealing valve itself has a valve having a function of controlling the operating pressure, there is an advantage that the operating pressure can be easily controlled by changing the rubber hardness or the like.
[0045]
Example 4
The same configuration as in Example 1 except that the diameter of the valve portion is 1.15 times the diameter of the injection hole and the sealing valve is made of EPDM having a rubber hardness of 40 for the sealing valve. A polymer battery having the following characteristics was prepared, and the same cycle test as in Example 1 was performed for evaluation. As a result, the capacity change abnormality number was 0, the ESR change abnormality number was 1, and the appearance abnormality number was 0.
[0046]
In this embodiment, the valve diameter of the sealing plug is changed. The rubber hardness of the sealing valve was lowered to optimize the valve diameter. As a result, as in Example 1, the degassing operation was performed with high accuracy, and stable battery characteristics were obtained. Thus, the sealing plug of the present invention has an advantage that the operating pressure can be easily controlled by changing not only the rubber hardness but also the diameter of the valve.
[0047]
(Example 5)
A polymer battery having the same configuration as in Example 1 was prepared except that the sealing valve was coated with a fluororesin on the sealing valve, and the same cycle test as in Example 1 was performed for evaluation. As a result, the capacity change abnormality number was 0, the ESR change abnormality number was 0, and the appearance abnormality number was 0. The coating thickness of the fluororesin was about 20 μm.
[0048]
In this embodiment, the sealing plug is coated with a fluorine resin having water repellency. Thereby, the evaporation of the electrolytic solution is suppressed through the sealing plug, and an effect of reducing the occurrence of capacity abnormality due to the electrolytic solution volatilization is expected. Thus, in the present invention, there is an advantage that a special effect can be brought about by surface treatment on the sealing valve itself.
[0049]
(Example 6)
The same sealing as in Example 3 except that the sealing plug uses a sealing plug made of EPDM having a rubber hardness of 30 for the sealing valve and the diameter of the valve is 1.15 times the diameter of the injection hole. An electric double layer capacitor having a structure was prepared, and the same cycle test as in Example 1 was performed and evaluated. As a result, the capacity change abnormality number was 0, the ESR change abnormality number was 1, and the appearance abnormality number was 0.
[0050]
In this example, as in Example 3, the sealing plug of the present invention was used for the electric double layer capacitor using activated carbon for the electrode. However, the increase in internal pressure due to slight gas generation is sensitively influenced by the ESR value. As a result of optimizing the electric double layer capacitor by taking advantage of this sealing valve capable of controlling pressure from both sides of the rubber hardness and the valve diameter, as in the first embodiment, the degassing operation occurs with high accuracy and the stable electric double-layer capacitor. The capacitance characteristics of the multilayer capacitor were obtained.
[0051]
(Comparative Example 1)
The configuration of a sealed battery using a conventional sealing plug is as follows. FIG. 7 shows the structure of a battery using a conventional sealing plug. FIG. 7 shows a portion where the sealing plug 11 blocks the liquid injection hole 14 provided in the gasket 12 by fixing the support plate 10 with the adhesive 13. The sealing plug 11 is made of a rubber material having elasticity. The support plate 10 is used for fixing the sealing plug 11 and is made of a plastic or metal material that is difficult to deform itself. Configurations other than these sealing structures are the same as those shown in the first embodiment of the present invention.
[0052]
A cycle test similar to that in Example 1 was performed and evaluated. As a result, the capacity change abnormality number was 5, the ESR change abnormality number was 16, and the appearance abnormality number was 7.
[0053]
The comparative example 1 had many characteristic abnormalities, which is considered to be due to the following reason. The sealing structure of Comparative Example 1 employs a method of fixing the sealing plug with a support plate, but this is not controlled by the elasticity of the sealing plug, but the control of the gas release due to the increase in internal pressure. This is because it changes depending on the state in which the stopper is fixed. In other words, if the pressure at which the support plate holds down the sealing plug is weakened due to the bonding state of the support plate, the operating pressure of the plug decreases, and conversely, when the pressure at which the sealing plate of the support plate is suppressed increases, the operating pressure of the plug becomes Get higher. The elasticity of rubber is almost determined by the rubber material and is not much different, but the pressure at which the support plate holds the sealing plug is difficult to control and varies widely. For this reason, the variation in the internal pressure control of the battery has increased, and it can be said that the battery characteristics in the cycle were not stable.
[0054]
(Comparative Example 2)
An electric double layer capacitor having the same configuration as in Comparative Example 1 was prepared except that activated carbon was used as an electrode, and the same cycle test as in Example 1 was performed for evaluation. As a result, the capacity change abnormality number was 4, the ESR change abnormality number was 28, and the appearance abnormality number was 9.
[0055]
Since this comparative example 2 is an electric double layer capacitor in which the increase in internal pressure due to slight gas generation is sensitively influenced by the ESR value, it is greatly affected by variations in internal pressure control and is more abnormal than the comparative example 1. .
[0056]
Table 1 summarizes the evaluation results of the electricity storage devices of the examples of the present invention and the comparative example.
[0057]
[Table 1]

[0058]
【The invention's effect】
As described above, the sealing plug of the present invention has elasticity and has a truncated cone-shaped valve portion narrowed in the injection direction into the liquid injection hole. When used as a stopper, it has the following effects.
(1) Since the sealing plug itself has a valve action, the valve operating pressure can be adjusted arbitrarily and accurately, and the explosion-proof safety when the internal pressure of the electricity storage device increases due to gas generation can be improved.
(2) In addition, when the internal pressure is reduced by releasing the gas inside the electricity storage device to the outside of the device, the sealing plug returns to its original state and the sealed state is maintained again. Therefore, the original charge / discharge function can be exhibited without any trouble without causing gas leakage or liquid leakage.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a structure of a sealing plug according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing another structural example of the sealing plug of the present invention.
FIGS. 3A and 3B are diagrams of a sealing portion of the sealed electric storage device according to the first embodiment using the sealing plug of the present invention, in which FIG. 3A is a plan view, and FIG. 'Is a cross-sectional view along the line.
FIGS. 4A and 4B are diagrams of a sealing portion of a hermetic power storage device according to a second embodiment using the sealing plug of the present invention, where FIG. 4A is a plan view and FIG. 'Is a cross-sectional view along the line.
FIGS. 5A and 5B are diagrams of a sealing portion of a sealed electric storage device according to a third embodiment using the sealing plug of the present invention, in which FIG. 5A is a plan view and FIG. (C) is a cross-sectional view taken along line BB 'in (a).
6A and 6B are views of a sealing portion of a sealed electric storage device according to a fourth embodiment using the sealing plug of the present invention, where FIG. 6A is a plan view, and FIG. 6B is an AA view of FIG. (C) is a cross-sectional view taken along line BB 'in (a).
FIG. 7 is a cross-sectional view showing the structure of a battery using a conventional sealing plug.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Support body 2 Valve part 2a Valve shaft part 3 Sealing valve 4,12 Gasket 5,13 Adhesive 6,14 Injection hole 7 Exhaust groove 8 Exhaust notch part 10 Support plate 11,50 Sealing plug 20 Metal rod 30 groove 40 recess

Claims

A sealed electricity storage device that is externally provided with a gasket, includes a cylindrical liquid injection hole for electrolyte in the gasket, and the liquid injection hole is sealed with a sealing plug, the sealing plug being the liquid injection mounted in the hole, to seal the interior of the electric storage device, a plate-like support, is connected to the support, and a sealing valve that is inserted into the injection hole, the sealing valve is the support A valve shaft portion connected to the body, and a valve portion connected to the valve shaft portion and having a truncated cone-like elasticity that narrows in the insertion direction, and the diameter of the upper end surface outer shape of the valve portion is the note. A sealed electric storage device , which is 1.1 to 1.3 times the diameter of the liquid hole, and the width of the support is smaller than the diameter of the liquid injection hole .

A sealed electricity storage device that is externally provided with a gasket, includes a cylindrical liquid injection hole for electrolyte in the gasket, and the liquid injection hole is sealed with a sealing plug, the sealing plug being the liquid injection mounted in the hole, to seal the interior of the electric storage device, a plate-like support, is connected to the support, and a sealing valve that is inserted into the injection hole, the sealing valve is the support A valve shaft portion connected to the body, and a valve portion connected to the valve shaft portion and having a truncated cone-like elasticity that narrows in the insertion direction, and the diameter of the upper end surface outer shape of the valve portion is the note. It is 1.1 to 1.3 times the diameter of the liquid hole, the width of the support is larger than the diameter of the liquid injection hole, and the support is provided with a groove that is connected to the liquid injection hole. A sealed electric storage device .

A sealed electricity storage device that is externally provided with a gasket, includes a cylindrical liquid injection hole for electrolyte in the gasket, and the liquid injection hole is sealed with a sealing plug, the sealing plug being the liquid injection mounted in the hole, to seal the interior of the electric storage device, a plate-like support, is connected to the support, and a sealing valve that is inserted into the injection hole, the sealing valve is the support A valve shaft portion connected to the body, and a valve portion connected to the valve shaft portion and having a truncated cone-like elasticity that narrows in the insertion direction, and the diameter of the upper end surface outer shape of the valve portion is the note. It is 1.1 to 1.3 times the diameter of the liquid hole, the width of the support is larger than the diameter of the liquid injection hole, and the support includes a notch that is connected to the liquid injection hole. A sealed electricity storage device characterized by.

The sealed electric storage device according to any one of claims 1 to 3, wherein an end portion of the support body of the sealing plug is fixed to the surface of the gasket with an adhesive.

With a recess in the surface of the gasket, it said support being attached to the recess, according to claim 1 or 3 ends of the support is characterized in that it is adhesively secured to a surface of the gasket Sealed electricity storage device.

6. The sealed electric storage device according to claim 4, wherein the adhesive is a silicone resin or an epoxy resin.

The sealed electric storage device according to any one of claims 1 to 6, wherein a rubber material is used as a material of the valve portion.

The sealed electric storage device according to any one of claims 1 to 7, wherein a surface of the valve portion is coated with a fluororesin.

The sealed electric storage device according to claim 7, wherein a terpolymer of ethylene, propylene and a non-conjugated diene compound is used as the rubber material.

The sealed electric storage device according to any one of claims 1 to 9 , wherein the support is a rubber plate or a metal plate.

The sealed power storage device according to any one of claims 1 to 6, wherein the support and the valve portion are made of a rubber material, and the support is harder than the valve portion. .

The sealed electricity storage device according to any one of claims 7, 9, and 11 , wherein the rubber material of the valve portion has a hardness of 20 to 60.

The sealed electric storage device according to any one of claims 1 to 12 , wherein a metal rod is inserted into the valve shaft portion of the sealing valve.

According to any one of claims 1 to 13, characterized in that the grooves in a ring shape is formed between the valve portion edge and the boundary between the valve shaft portion of the upper end face of the valve portion Sealed electricity storage device .

Claims, characterized a positive electrode comprising poly-cyano indole as an active material across the porous separator within said gasket, a negative electrode containing a polyquinoxaline as an active material, that it has a battery element having a sulfuric acid aqueous solution as an electrolytic solution The sealed electricity storage device according to any one of 1 to 14 .

The hermetic seal according to any one of claims 1 to 14, further comprising an electric double layer capacitor element having a pair of activated carbon electrodes sandwiching a porous separator in the gasket and an aqueous sulfuric acid solution as an electrolytic solution. Power storage device.