JP4106206B2

JP4106206B2 - Electrochemical cell

Info

Publication number: JP4106206B2
Application number: JP2001296932A
Authority: JP
Inventors: 信雄安東; 之規羽藤
Original assignee: Kanebo Trinity Holdings Ltd
Current assignee: Kracie Holdings Ltd
Priority date: 2001-09-27
Filing date: 2001-09-27
Publication date: 2008-06-25
Anticipated expiration: 2021-09-27
Also published as: JP2003109653A

Description

【０００１】
【産業上の利用分野】
本発明は電気化学セルに関し、特に、組み立て及び分解が容易であり、電池材料の評価を効率的に行なえる電気化学セルに関する。
【０００２】
【従来の技術】
従来、電池材料の性能評価に使用される電気化学セルは、正極と負極をセパレーターを介して対向配置させてなる電極体の少なくとも一組を収納容器に配置し、蓋部をかぶせ、該収納部と蓋部を複数のネジにより締結して構成される。このような電気化学セルの例として、宝泉株式会社製のＨＳセル及び三極セルが挙げられる。これらのセルを組み立てる際には、ネジの片締めに起因する問題、例えば、電極部材間の接圧の偏り、電極間の距離の偏り、電極相互の位置ずれ、及びセルの不完全な密閉等が起きないように留意する必要がある。また、分解する際にも、複数のネジをゆるめなければならないので、手間を要し、電極の交換効率及び評価効率の点で改良の余地がある。
【０００３】
また、円筒型電池における電極面積や厚み等の効果を評価する場合には、リボン状の電極体をスパイラル上に捲き回し、外装容器に充填後、負極端子と該外装容器、及び、正極端子とトップキャップとをそれぞれ溶接し、電解液を注液して、トップキャップを容器にかしめて電気化学セルとする。しかし、かしめる際には、液漏れ等の無いようシール剤を塗布して、かしめる角度を調節しなければならず、手間がかかる上に困難である。また、かしめた後に接触不良等の不具合を見出した場合には、トップキャップを壊さなければならない。
【０００４】
【発明が解決しようとする課題】
そこで本発明は、ネジ止め又はかしめ操作無く、容易且つ片締めなく組み立てることができ、分解も容易な電気化学セルを提供することを目的とする。
【０００５】
【課題を解決するための手段】
すなわち、本発明は少なくとも１組の作用極と対極をセパレーターを介して対向配置してなる電極体、該電極体を収納するための収納容器及び該収納容器の蓋部からなる電気化学セルにおいて、該蓋部の面積と略同じ面積の押圧面を備える加圧手段をさらに備え、該押圧面により該蓋部の略全面を該収納容器側に押圧することにより該収納容器が密閉されることを特徴とする電気化学セルである。
上記発明の好ましい態様は以下のものである。
該加圧手段がハンドプレスまたは万力であることを特徴とする該電気化学セル。
該電極体が、少なくとも１つの参照極をさらに含み、且つ、該収納容器と該蓋部の間に少なくとも１個の胴部を有することを特徴とする該電気化学セル。
該電極体がスパイラル状電極体であることを特徴とする該電気化学セル。
該収納容器内に、該スパイラル状電極体を収納するための、電気絶縁性材料からなる中空柱状部材をさらに備え、及び、該中空柱状部材の上端面と該蓋部の間に導電性材料からなる弾性部材をさらに備え、該加圧手段により該蓋部を該収納容器側に押圧することによって、該電極体のリードの一つが該中空柱状部材の上端面上で該弾性部材と接圧され、且つ、該電極体の他のリードが該中空柱状部材の下端面の下側で該収納容器の底部と接圧されることを特徴とする該電気化学セル。
該電極体が板状構造を有し、且つ、該電極体と該蓋部との間に弾性部材をさらに備え、該加圧手段により該蓋部を該収納容器側に押圧することにより該弾性部材を介して、該作用極、該セパレーター及び該対極が相互に接圧されることを特徴とする該電気化学セル。
該弾性部材が導電性材料からなり、該加圧手段により該蓋部を該収納容器側に押圧することにより、該弾性部材が該電極体のリードの一つと接圧されることを特徴とする該電気化学セル。
該弾性部材が巻きバネであることを特徴とする該電気化学セル。
【０００６】
【発明の実施の態様】
以下、本発明の電気化学セルを図面を参照して説明する。
図１は、本発明の電気化学セルの一実施態様の正面図である。同図は、加圧手段１により、蓋部２２が電極収納容器２１の開放端に圧着されて、収納容器２１が密閉されている状態を表す。該加圧手段１によれば、蓋と容器の複数のネジ孔を合わせて締結する煩わしさや、かしめる角度を調製する必要がない。また、一旦密閉した後に、何らかの不具合が検出された場合にも、加圧手段１を緩めるだけでセルを分解して不具合を直し、新たに組み立て直すことが容易にでき、複数のネジを緩めたり、かしめ部を破壊する煩わしさが無い。
【０００７】
さらに、加圧手段１の押圧面の面積を蓋部２２のそれとほぼ同じにして、蓋部２２全面を押圧するようにすれば、セルの各部が均等に押圧される結果、ネジの片締め又はかしめ角度の傾きに起因する電極間の接圧状態の不均一性、液漏れ等を回避できる。該加圧手段１としては、公知のプレス機、例えばハンドプレス、クランクプレス、油圧プレス、水圧プレス、及び、万力などを用いることができる。なかでも、小型のハンドプレスおよび万力が使い易いので好ましい。また、加圧手段１には、圧力を正確に調整するための、圧力計を備えてもよい。なお、押圧の方向は上方からに限られず、下から押し上げる、または横方向に押圧してもよい。また、加圧手段１と蓋部２２の間および加圧手段１と電極収納容器２１の間を電気的に絶縁するためには、電気絶縁性材料、例えばポリプロピレン、のシートを挟んでもよく、あるいは、電極収納容器２２をポリプロピレン製等の外装ケース３に収納してもよい。
【０００８】
図２は、電極収納容器２１および蓋部２２からなる電気化学セル本体２の一実施態様の断面図である。電極収納容器２１内に電極体が収納される。収納容器２１および蓋部２２の形状および構成材料には特に制限はなく、金属製、プラスチック製、またはセラミック製の円筒、角柱形状であってよい。収納容器２１及び蓋部２２を、例えばSUS316等の金属製にすれば、それぞれを電極リードにすることができるので好ましい。さらに、みのむしクリップ等で挟み易いように、収納容器２１及び蓋部２２にネジ製の外部端子５１および５２を設けてもよい。好ましくは、電極収納容器２１の外部端子５１に作用極を、蓋部２２の外部端子５２に対極を接続させる。外部端子は、構成する電池の電解液、及びセル電圧等に依存して、腐食、反応、及び溶解等の無い材料を適宜選択して構成することができる。
【０００９】
電極収納容器２１と蓋部２２との間の密閉性を高めるために、Ｏ−リング７を用いることが望ましい。Ｏ−リング７は、高い弾性率、および耐電解液性を有する材料、例えば、ポリテトラフルオロエチレン（ＰＴＦＥ）、ブチルゴム（ＩＩＲ）、エチレン／プロピレン／ジエン三元共重合体（ＥＰＤＭ）からなることが好ましい。電極収納容器２１と蓋部２２をプラスチックで構成する場合には、O−リング等を使用する代わりに、容器及び蓋部の端部を夫々テーパー状のオスとメスにして密閉するようにしてもよい。
【００１０】
電極収納容器２１と蓋部２２を電極リードとして用いる場合、これらが互いに電気的に絶縁されるように、収納容器２１と蓋部２２との間に、スペーサー６をさらに用いる。該スペーサー６は、電気絶縁性、好ましくは例えばポリプロピレン、から構成してよい。該スペーサーを使用すれば、電極収納容器２１と蓋部２２の隙間を平行にして圧力が均一に加わるようにするパッキングとしても作用するので好ましい。
【００１１】
図３は、電極収納容器２１と蓋部２２の間に胴部２３を有する本発明におけるセルの一態様を示す。本態様は、電極体が少なくとも１つの参照極をさらに有する３極の構成である場合に適し、電極収納容器２１、蓋部２２、及び胴部２３のそれぞれを作用極、対極、および参照極リードとすることができる。上述したように、クリップ等で挟み易いように、外部端子５１、５２、５３を設けることが好ましい。好ましくは、各外部端子５１〜５３を、それぞれ２個ずつ、より好ましくは３個ずつ設ける。各外部端子を複数にすることで、任意の２極間の電位をモニターする際、該外部端子にみのむしクリップ等を固定すればレコーダーのプラス端子およびマイナス端子へ入力することができ、配線が楽に行なえるので便利である。図３に示す実施態様において、ネジ511及び531は、それぞれ作用極及び参照極からのリード又は集電体端子を固定するするために用いられる。
【００１２】
図４は本発明のセルに収納される電極体の一態様であるスパイラル状電極体を示す。同図においてスパイラル状電極体８は、少なくとも１組の作用極（負極）８１及び対極（正極）８２、及び各々の集電体８５及び８６にリード811及び821を夫々溶接したものを、セパレータ８３を挟んで重ね、巻き回して作られる。該スパイラル状電極体８は参照極を含んでもよい。
【００１３】
スパイラル状電極体８を収納容器２１に収納する場合には、収納容器２１の底部に、一のリード、例えばリード811を接続し、他のリード821を蓋部２２に接続させて収納することができる。この時、集電体８５からのリードは、リード固定治具５１１に固定されて、該リード固定治具５１１を介して外部端子５１に接続されてもよい。該電極体８は、そのままで、又はセパレーターを巻いて収納してよいが、好ましくは図５に示すように、電極収納容器２１に収納される中空柱状部材であって、電気絶縁性材料、例えばポリプロピレン、ポリフェニレンサルファイド、からなる中空柱状部材４の該中空部にスパイラル状電極体８を収納したものを収納容器２１に収納する。中空柱状部材４を用いれば作業性が良くなり好ましい。
【００１４】
さらに好ましくは、図５に示すように、中空柱状部材４の上端面上と蓋部２２の間に弾性部材１０を備え、蓋部２２を加圧手段１で電極収納容器２１側へ押圧することによって、弾性部材１０が中空柱状部材４を押圧し、該中空柱状部材４の下端面で作用極リード811が電極収納容器２１の底部に押さえつけられて容器２１と接圧されるようにする。特に好ましくは、弾性部材１０が導電性材料からなり、蓋部２２を加圧手段１で収納容器２１側へ押圧することによって、対極リード812が中空柱状部材４の上端面上で弾性部材１０と接触させられて、蓋部２２へと導通される。なお、図５において、中空柱状部材４及び電極体８の高さは収納容器２１の深さと同じであるが、必ずしも同じである必要はなく、中空柱状部材４の高さは電極体８の高さ以上で収納容器２１の深さ以下の間で変えてよい。又、中空柱状部材４の中空部の形状は、その内部に収納する電極体の形状に合わせて、円柱状又は四角柱状等であってよい。
【００１５】
弾性部材１０としては、各種のバネ、例えば巻きバネ、板バネ、棒バネ、輪バネ、柱形状のプラスチックもしくはゴム、複数のパッキングを重ねたもの等を用いることができるが、好ましくは、金属製の巻きバネが用いられる。さらに、電気抵抗を下げるために、表面にアルミニウム、ニッケル等のめっきを施してもよく、その際、構成する電池の電解液、及びセル電圧等に依存して、腐食、反応、及び溶解等の無い物質を適宜選択することができる。
【００１６】
図６は、本発明のセルに収納される電極体の他の態様である板状電極体の断面図である。同図において、板状電極体９の作用極９１と対極９２がセパレーター９４を介して対向配置される。好ましくは、参照極９３を有し、作用極９１と参照極９３が、例えばポリプロピレン製の電気絶縁性層991を挟んで配置される。各電極９１〜９３は、集電体９５〜９７を介して、外部端子５１〜５３にそれぞれ接続される。この時、集電体９５、９７からのリードは、リード固定治具531、511に夫々固定されて、外部端子５３、５１に夫々接続されてもよい。
【００１７】
板状電極体９は、複数組の作用極と対極及び参照極からなってよい。例えば図７は、2組の作用極と対極を接続して電極体を構成する場合の断面図である。同図において、並列接続する場合には、作用極911と912の端子を接続し、対極921と922の端子を接続し、及び対極922と参照極９３の間を板状体991で電気的に絶縁する。作用極911と912の間は、板状体991で絶縁してもよいが、直接接圧させ又は板状体991に代えて導電体を挟むことで、より容易に並列接続を得ることができる。一方、直列接続する際には作用極911と対極922とを接続する。又は、図７において作用極912と対極922の位置を入れ替えて、該対極922と作用極911とを板状体991に代えて導電体を介して重ねることで、より容易に直列接続を得ることができる。なお、これらの電極配置の態様に応じて、ゲル系の電解液を用いる等により、各電極の組毎の電解液が相互に混じり合わないようにする。
【００１８】
図８は、板状電極体９が収納された状態を示す。加圧手段１により蓋部２２を押圧すると、蓋部２２と板状電極体９の間に配置された弾性部材１０を介して板状電極体９が押圧されて、各電極とセパレーターとの間、及び各電極と集電体との間の接圧が達成される。同時に、板状電極体９がセル内で固定される。このように、押圧操作のみにより、従来、複数のネジ止め操作で固定及び接圧を行なっていたのに比べてより均一な接圧をより容易に達成することができる。弾性部材１０としては、既に述べたように各種のバネ、柱形状のプラスチックもしくはゴム、複数のパッキングを重ねたもの等を用いることができる。好ましくは、巻きバネが用いられる。該バネの直径、およびバネ定数を適宜選択することにより、実際の円筒型電池やコイン型電池において電極にかかる荷重、および電極間距離に設定することができる。また、弾性部材１０からの圧力を、電極体に均一に伝えるために、電極体の上に図７に示す板状部材992を置いてもよい。板状電極体９の板状部材992は、適度な硬さを有する物質からなっていればよく、例えば、ポリプロピレン製であってよい。
【００１９】
好ましくは、弾性部材１０が導電性材料、例えば金属からなり、電極リードとして用いられる。図９は図８の電極体９の拡大断面図である。同図において、対極９２の集電体９６の端子が、ポリプロピレン製の板状部材992の裏側へと伸ばされており、加圧手段１で蓋部２２を収納容器２１側に押圧すると、弾性部材１０が該集電体端子を上から押さえ、対極９２と蓋部２２とを導通させる。
【００２０】
なお、板状電極体９も、スパイラル状電極体８と同様に、該電極体を収納するための中空柱状部材４を用いて収納すれば、電極部材相互の位置ずれや、電極と容器２１との接触を回避することができるので好ましい。
【００２１】
本発明における電極体の構成材料には特に制限はなく、種々の組合わせを使用することができる。有機電解液電池、例えば、リチウムイオン電池の負極材料を評価する場合には、作用極８１に炭素系材料、例えば天然黒鉛、不定形炭素等、有機高分子焼成体等の負極材料からなる電極、または、リチウム遷移金属化合物、二酸化マンガン、フッ化黒鉛等の正極材料を用い、対極８２及び参照極８３にリチウム金属箔、炭素などを用いる。また、セパレーター８４としてはガラス繊維からなる不織布又はポリエチレン等のポリオレフィン系微孔性フィルム用いることができる。水系電池の場合には、作用極８１として水酸化ニッケル、対極８２として水酸化カドミウムを用いたNi−Cd電池系や、作用極８１および対極８２に活性炭を用いた水系キャパシタも構成することができる。集電体としては、ステンレススチール（オーステナイト系、フェライト系等）、スチール、アルミニウム、銅、ニッケル、チタン、炭素からなるメッシュ又は箔など、構成する電池の電解液、及びセル電圧等に依存して、腐食、反応、及び溶解等の無い材料を適宜選択することができる。
【００２２】
尚、セル内部にガスが発生し、セル内の圧力が高くなる場合には、蓋部２２に安全機構、例えば、蓋部２２の一部に孔を貫通させ、Al−PETおよびAl−PPなどのラミネートフィルムの樹脂面を蓋部２２に接触させて置き、ホットプレスにより該孔を塞いでなる安全弁、又は、圧力弁を備えることが好ましい。
【００２３】
以下に、本発明の実施例を示す。
実施例１
アルゴンボックス中で、下記のリチウムイオン電池を収納した電気化学セルを組み立てた。厚さ５mmのフェノール樹脂成形板をシリコニット電気炉中に入れ、窒素雰囲気下で、50℃／時間の速度で500℃まで昇温し、更に、10℃／時間の速度で 650℃まで昇温して熱処理して合成したポリアセン（ＰＡＳ）を、ディスクミルで粉砕して、平均粒径約７μmの粉体とした。このPAS粉体のH／C比は0.22であった。次に、該PAS粉体100重量部と、アセチレンブラック10重量部とポリフッ化ビニリデン粉末10重量部をN−メチルピロリドン120重量部に溶解した溶液を十分に混合してスラリーを得た。該スラリーを厚さ20μmの銅箔の片面に塗布してプレスし、厚さ110μmのPAS作用極９１を得た。これを１５×２０ｍｍの大きさにカットし、SUSメッシュ集電体９５に重ねた。
参照極９３は、SUSメッシュ集電体９７の上に、厚さ200μm、１５×２０ｍｍの大きさの金属リチウムを圧着して調製した。また、対極９２は、SUSメッシュ集電体９６の上に、厚さ200μm、１５×２０ｍｍの大きさの金属リチウムを圧着して調製した。
電解液として、プロピレンカーボネートに六フッ化リン酸リチウム（LiPF₆）を１モル／lの濃度で溶解させた溶液を用いた。セパレーター９４として、ガラス繊維からなるフェルトを用いた。なお、集電体９５および９７は、厚さ２ｍｍのポリプロピレン製電気絶縁層991の両面にそれぞれ固定し、SUSメッシュ集電体９６は、厚さ５ｍｍのポリプロピレン製板９９２の片面からその裏面へと、折り曲げた。
電極収納容器２１の底にセパレーター９４を敷き、その上にリチウム金属面を下側にして参照極９３、ポリプロピレン板991、銅箔面を下側にしてＰＡＳ作用極９１、セパレーター９４、リチウム金属面を下側にして対極９２、および厚さ５ｍｍのポリプロピレン製板状部材992の順に積層した。作用極９１の集電体９５を外部端子５１に接続後、電極収納容器２１の上端にポリプロピレン製スペーサー６とブチルゴム製Ｏ−リング７を置き、胴部２３を重ね、参照極９３の集電体９７を外部端子５３に接続した。次いで、電極収納容器２１と胴部２３の積層体を外装ケース３に入れ、電解液を注入し、ベルジャーをかぶせて減圧下で電解液をセパレーター９４及び作用極９５に充分含浸させた。
次いで、胴部２３の上端にポリプロピレン製スペーサー６とブチルゴム製Ｏ−リング７を置き、ポリプロピレン製板状部材992の上にＳＵＳ製巻きバネ１０を置き、その上に蓋部２２を乗せて、上からハンドプレス１で下方に圧縮して、胴部２３の上端に密着させた。
上記電気化学セルの組み立ては、作業性の悪いアルゴンボックス中でも約５分しかかからず、容易に行なうことができた。
【００２４】
比較例１
実施例と同様の電極体を用い、ネジで４点を固定するタイプの電気化学セルを組み立てた。電極収納容器と蓋部の４つのネジ孔を一致させるのが困難であり、組み立てに１０分以上かかった。
【００２５】
実施例２
円筒型のリチウムイオン電池を作成した。アルミ箔の両面にLiCoO₂を塗布し、非塗布部にアルミリード821を超音波溶接して対極（正極）８２を調製した。銅箔の両面にグラファイトを塗付し、非塗布部にニッケルリード811を超音波溶接して作用極（負極）８１を調製した。作用極８1と対極８２をセパレーター８３を介して重ねて巻き回し、スパイラル状電極８を得た。
収納容器２１内に管形状のポリプロピレン製中空柱状部材４を挿入し、その中にスパイラル状電極８を入れ、ニッケルリード811を、収納容器２１底部と中空柱状部材４の下端面との間に配置し、中空柱状部材４が押圧されることによって、ニッケルリード811が収納容器２１と電気的に接続されるようにした。一方、アルミリード821は、図５に示すように、蓋部２２を押圧することにより、巻きバネ１０と中空柱状部材４の上端面との間に挟まれて、巻きバネ１０を介して蓋部２２に電気的に接続するよう折り曲げた。電極収納容器２１を外装ケース３に挿入後、実施例１と同様の電解液を注入し、ベルジャーをかぶせて減圧下で作用極８１、対極８２及びセパレーター８３に電解液を充分含浸させ後、中空柱状部材４の上端面のアルミリード811上に巻きバネ１０を、さらにその上に蓋部２２を乗せて、ハンドプレス１で下方に押し、蓋部２２を収納容器２１の上端に密着させて円筒型電池評価用セルを得た。
上記組み立てを10本行なった。電極の巻き取りを失敗して、電池にすることができなかった１本を除き、総て良好な電池となった。１本あたりの組み立て所要時間は、約40分であった。
【００２６】
比較例２
実施例２と同様のスパイラル状電極を、外装缶に入れ、負極のニッケルリードを缶底部に抵抗溶接して、缶上部をネッキングした。次に、缶上部にガスケットを装着後、正極のアルミリードをトップキャップに超音波溶接した。電解液を注液後、トップキャップと缶にかしめて、円筒型電池を得た。この組み立てを10本行なったが、リードの溶接不良が３本、液漏れが２本、巻き取り不良が１本、巻に挿入できなかったものが２本あり、最終的に電池となったのは、２本であった。１本あたりの組み立て所要時間は、約１時間であった。
【００２７】
【発明の効果】
本発明の電気化学セルは、加圧手段を用いることにより、組み立てが容易で、且つ、各電池部材間が均一に接圧される。また、分解も容易であるから、電極の交換等も容易にできる。
【００２８】
【図面の簡単な説明】
【図１】本発明の電気化学セルの一実施態様の斜視図である。
【図２】本発明における電気化学セル本体の一実施態様の断面図である。
【図３】本発明における電気化学セル本体の他の実施態様の断面図である。
【図４】本発明におけるスパイラル状電極体の斜視図である。
【図５】スパイラル状電極体が電気化学セルに収納された状態を表す断面図である。
【図６】本発明の電気化学セルにおける板状電極体の一態様の断面図である。
【図７】本発明の電気化学セルにおける板状電極体の他の態様の断面図である。
【図８】板状電極体が電気化学セルに収納された状態を表す断面図である。
【図９】図８における板状電極体の拡大断面図である。
【００２９】
【符号の説明】
１加圧手段
２電気化学セル本体
２１電極収納容器
２２蓋部
２３胴部
３外装ケース
４中空柱状部材
５１〜５３外部端子
511及び531 リード固定治具
６スペーサー
７Ｏ−リング
８スパイラル状電極体
８１作用極
８２対極
８３セパレーター
８５及び８６集電体
８１１作用極リード
８２１対極リード
９板状電極体
９１作用極
９２対極
９３参照極
９４セパレーター
９５〜９７集電体
911及び912 作用極
921及び922 対極
991 電気絶縁性層
992 板状部材
１０弾性部材[0001]
[Industrial application fields]
The present invention relates to an electrochemical cell, and more particularly, to an electrochemical cell that is easy to assemble and disassemble and can efficiently evaluate battery materials.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an electrochemical cell used for performance evaluation of battery materials has at least one set of electrode bodies in which a positive electrode and a negative electrode are arranged to face each other with a separator placed in a storage container, and a cover is placed on the storage cell. And the lid portion are fastened by a plurality of screws. Examples of such electrochemical cells include HS cells and triode cells manufactured by Hosen Co., Ltd. When assembling these cells, problems caused by screw tightening, such as uneven contact pressure between electrode members, uneven distance between electrodes, misalignment between electrodes, and incomplete sealing of cells, etc. It is necessary to be careful so that this does not occur. Also, when disassembling, since a plurality of screws must be loosened, it takes time and there is room for improvement in terms of electrode replacement efficiency and evaluation efficiency.
[0003]
Further, when evaluating the effects such as the electrode area and thickness in the cylindrical battery, the ribbon-shaped electrode body is rolled on a spiral and filled in the outer container, and then the negative electrode terminal, the outer container, and the positive electrode terminal The top cap is welded to each other, an electrolytic solution is injected, and the top cap is caulked in a container to form an electrochemical cell. However, when caulking, it is necessary to apply a sealing agent so as not to leak liquid and adjust the caulking angle, which is troublesome and difficult. In addition, if a defect such as poor contact is found after caulking, the top cap must be broken.
[0004]
[Problems to be solved by the invention]
Therefore, an object of the present invention is to provide an electrochemical cell that can be assembled easily and without clamping, without screwing or caulking, and can be easily disassembled.
[0005]
[Means for Solving the Problems]
That is, the present invention relates to an electrode body in which at least one set of working electrode and counter electrode are arranged to face each other via a separator, a storage container for storing the electrode body, and an electrochemical cell including a lid portion of the storage container. lid unit area and further comprising a substantially pressurizing means comprising a pressing surface of the same area of that said container is sealed by pressing substantially the whole surface of the lid portion to the container side by the pressing surface It is the electrochemical cell characterized.
Preferred embodiments of the invention are as follows.
The electrochemical cell, wherein the pressurizing means is a hand press or a vise.
The electrochemical cell, wherein the electrode body further includes at least one reference electrode, and has at least one barrel portion between the storage container and the lid portion.
The electrochemical cell, wherein the electrode body is a spiral electrode body.
The storage container further includes a hollow columnar member made of an electrically insulating material for storing the spiral electrode body, and a conductive material is formed between the upper end surface of the hollow columnar member and the lid portion. And pressing one of the leads of the electrode body against the elastic member on the upper end surface of the hollow columnar member. The electrochemical cell is characterized in that the other lead of the electrode body is brought into contact with the bottom of the storage container below the lower end surface of the hollow columnar member.
The electrode body has a plate-like structure, and further includes an elastic member between the electrode body and the lid portion, and the elastic body is pressed by pressing the lid portion toward the storage container by the pressurizing means. The electrochemical cell, wherein the working electrode, the separator, and the counter electrode are brought into contact with each other through a member.
The elastic member is made of a conductive material, and the elastic member is brought into contact with one of the leads of the electrode body by pressing the lid portion toward the storage container by the pressing means. The electrochemical cell.
The electrochemical cell, wherein the elastic member is a wound spring.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the electrochemical cell of the present invention will be described with reference to the drawings.
FIG. 1 is a front view of one embodiment of the electrochemical cell of the present invention. The figure shows a state in which the cover 22 is pressed against the open end of the electrode storage container 21 by the pressurizing means 1 and the storage container 21 is sealed. According to the pressurizing means 1, it is not necessary to adjust the troublesomeness of fastening the plurality of screw holes of the lid and the container together and the caulking angle. In addition, even if some trouble is detected after sealing once, the cell can be disassembled by simply loosening the pressurizing means 1 to fix the trouble, and it can be easily reassembled. There is no hassle of destroying the caulking portion.
[0007]
Furthermore, if the area of the pressing surface of the pressurizing means 1 is made substantially the same as that of the lid part 22 and the entire surface of the lid part 22 is pressed, each part of the cell is pressed evenly. Nonuniformity of the contact pressure state between the electrodes due to the inclination of the caulking angle, liquid leakage, etc. can be avoided. As the pressurizing means 1, known press machines such as a hand press, a crank press, a hydraulic press, a hydraulic press, and a vise can be used. Among these, a small hand press and a vise are preferable because they are easy to use. Further, the pressurizing means 1 may be provided with a pressure gauge for accurately adjusting the pressure. Note that the pressing direction is not limited to the above, and may be pushed up from below or pressed in the lateral direction. Further, in order to electrically insulate between the pressurizing means 1 and the lid portion 22 and between the pressurizing means 1 and the electrode storage container 21, a sheet of an electrically insulating material such as polypropylene may be sandwiched, or The electrode storage container 22 may be stored in an exterior case 3 made of polypropylene or the like.
[0008]
FIG. 2 is a cross-sectional view of an embodiment of the electrochemical cell main body 2 including the electrode storage container 21 and the lid portion 22. An electrode body is stored in the electrode storage container 21. There is no restriction | limiting in particular in the shape and constituent material of the storage container 21 and the cover part 22, A cylinder, prismatic shape made from metal, a plastic, or a ceramic may be sufficient. If the storage container 21 and the lid portion 22 are made of metal such as SUS316, for example, each can be used as an electrode lead, which is preferable. Further, external terminals 51 and 52 made of screws may be provided on the storage container 21 and the lid portion 22 so as to be easily sandwiched by a saw clip or the like. Preferably, the working electrode is connected to the external terminal 51 of the electrode container 21, and the counter electrode is connected to the external terminal 52 of the lid portion 22. The external terminal can be configured by appropriately selecting a material that does not corrode, react, dissolve, etc., depending on the electrolyte of the battery to be configured, the cell voltage, and the like.
[0009]
In order to improve the sealing property between the electrode storage container 21 and the lid portion 22, it is desirable to use the O-ring 7. The O-ring 7 is made of a material having a high elastic modulus and resistance to electrolyte, such as polytetrafluoroethylene (PTFE), butyl rubber (IIR), ethylene / propylene / diene terpolymer (EPDM). Is preferred. When the electrode storage container 21 and the lid portion 22 are made of plastic, instead of using an O-ring or the like, the ends of the container and the lid portion may be sealed with tapered males and females, respectively. Good.
[0010]
When the electrode storage container 21 and the lid portion 22 are used as electrode leads, the spacer 6 is further used between the storage container 21 and the lid portion 22 so that they are electrically insulated from each other. The spacer 6 may be composed of electrical insulation, preferably polypropylene, for example. The use of the spacer is preferable because it acts as a packing that applies a uniform pressure with the gap between the electrode container 21 and the lid portion 22 being parallel.
[0011]
FIG. 3 shows an embodiment of a cell according to the present invention having a body portion 23 between the electrode container 21 and the lid portion 22. This aspect is suitable when the electrode body has a three-pole configuration further including at least one reference electrode, and each of the electrode storage container 21, the lid portion 22, and the body portion 23 is a working electrode, a counter electrode, and a reference electrode lead. It can be. As described above, it is preferable to provide the external terminals 51, 52, and 53 so as to be easily sandwiched between clips. Preferably, two external terminals 51 to 53 are provided, more preferably three each. By using multiple external terminals, when monitoring the potential between any two poles, if the clip is fixed to the external terminal, it can be input to the plus and minus terminals of the recorder. Is convenient because it is easy to go. In the embodiment shown in FIG. 3, screws 511 and 531 are used to secure leads or current collector terminals from the working and reference electrodes, respectively.
[0012]
FIG. 4 shows a spiral electrode body which is an embodiment of the electrode body housed in the cell of the present invention. In the figure, a spiral electrode body 8 includes a separator 83 in which leads 811 and 821 are welded to at least one set of working electrode (negative electrode) 81 and counter electrode (positive electrode) 82, and current collectors 85 and 86, respectively. It is made by stacking and winding it. The spiral electrode body 8 may include a reference electrode.
[0013]
When the spiral electrode body 8 is stored in the storage container 21, one lead, for example, a lead 811, is connected to the bottom of the storage container 21, and the other lead 821 is connected to the lid portion 22 for storage. it can. At this time, the lead from the current collector 85 may be fixed to the lead fixing jig 511 and connected to the external terminal 51 via the lead fixing jig 511. The electrode body 8 may be stored as it is or wrapped with a separator, but preferably is a hollow columnar member stored in the electrode storage container 21, as shown in FIG. A hollow container 4 made of polypropylene and polyphenylene sulfide, in which the spiral electrode body 8 is housed in the hollow portion, is housed in the housing container 21. Use of the hollow columnar member 4 is preferable because workability is improved.
[0014]
More preferably, as shown in FIG. 5, the elastic member 10 is provided between the upper end surface of the hollow columnar member 4 and the lid portion 22, and the lid portion 22 is pressed toward the electrode storage container 21 by the pressurizing means 1. Thus, the elastic member 10 presses the hollow columnar member 4, and the working electrode lead 811 is pressed against the bottom of the electrode storage container 21 at the lower end surface of the hollow columnar member 4 so as to be in contact with the container 21. Particularly preferably, the elastic member 10 is made of a conductive material, and the counter electrode lead 812 is formed on the upper end surface of the hollow columnar member 4 with the elastic member 10 by pressing the lid portion 22 toward the storage container 21 with the pressurizing means 1. It is made to contact and is conducted to the lid part 22. In FIG. 5, the height of the hollow columnar member 4 and the electrode body 8 is the same as the depth of the storage container 21, but it is not necessarily the same. The height of the hollow columnar member 4 is the height of the electrode body 8. It may be changed between the above and below the depth of the storage container 21. Moreover, the shape of the hollow part of the hollow columnar member 4 may be a columnar shape, a square columnar shape, etc. according to the shape of the electrode body accommodated in the inside.
[0015]
As the elastic member 10, various springs such as a winding spring, a leaf spring, a rod spring, a ring spring, a columnar plastic or rubber, a plurality of packings, and the like can be used. No. spring is used. Furthermore, in order to lower the electrical resistance, the surface may be plated with aluminum, nickel, etc. At that time, depending on the electrolyte of the battery and the cell voltage, etc., corrosion, reaction, dissolution, etc. A substance that does not exist can be selected as appropriate.
[0016]
FIG. 6 is a cross-sectional view of a plate electrode body which is another embodiment of the electrode body housed in the cell of the present invention. In the same figure, the working electrode 91 and the counter electrode 92 of the plate electrode body 9 are disposed opposite to each other with a separator 94 interposed therebetween. Preferably, it has a reference electrode 93, and the working electrode 91 and the reference electrode 93 are disposed with an electrically insulating layer 991 made of polypropylene interposed therebetween, for example. The electrodes 91 to 93 are connected to the external terminals 51 to 53 via current collectors 95 to 97, respectively. At this time, the leads from the current collectors 95 and 97 may be fixed to the lead fixing jigs 531 and 511 and connected to the external terminals 53 and 51, respectively.
[0017]
The plate electrode body 9 may include a plurality of sets of working electrodes, counter electrodes, and reference electrodes. For example, FIG. 7 is a cross-sectional view when an electrode body is configured by connecting two sets of working electrodes and counter electrodes. In the figure, when connecting in parallel, the terminals of the working electrodes 911 and 912 are connected, the terminals of the counter electrodes 921 and 922 are connected, and the plate-like body 991 electrically connects between the counter electrode 922 and the reference electrode 93. Insulate. The working electrodes 911 and 912 may be insulated by a plate-like body 991, but a parallel connection can be obtained more easily by direct contact pressure or by sandwiching a conductor instead of the plate-like body 991. . On the other hand, when connecting in series, the working electrode 911 and the counter electrode 922 are connected. Alternatively, in FIG. 7, the positions of the working electrode 912 and the counter electrode 922 are interchanged, and the counter electrode 922 and the working electrode 911 are stacked via a conductor instead of the plate-like body 991, thereby obtaining a series connection more easily. Can do. In addition, according to the aspect of these electrode arrangement | positioning, it is made not to mix the electrolyte solution for every group of each electrode by using a gel type electrolyte solution etc., for example.
[0018]
FIG. 8 shows a state in which the plate electrode body 9 is housed. When the lid portion 22 is pressed by the pressurizing means 1, the plate electrode body 9 is pressed via the elastic member 10 disposed between the lid portion 22 and the plate electrode body 9, and between each electrode and the separator. And the contact pressure between each electrode and the current collector is achieved. At the same time, the plate electrode body 9 is fixed in the cell. As described above, the uniform contact pressure can be more easily achieved by only the pressing operation, compared to the case where the fixing and the contact pressure are conventionally performed by a plurality of screwing operations. As the elastic member 10, as described above, various springs, columnar plastics or rubbers, a plurality of packings, and the like can be used. Preferably, a wound spring is used. By appropriately selecting the diameter of the spring and the spring constant, it is possible to set the load applied to the electrodes and the distance between the electrodes in an actual cylindrical battery or coin-type battery. Further, in order to uniformly transmit the pressure from the elastic member 10 to the electrode body, a plate-like member 992 shown in FIG. 7 may be placed on the electrode body. The plate-like member 992 of the plate-like electrode body 9 only needs to be made of a material having an appropriate hardness, and may be made of, for example, polypropylene.
[0019]
Preferably, the elastic member 10 is made of a conductive material, such as metal, and is used as an electrode lead. FIG. 9 is an enlarged cross-sectional view of the electrode body 9 of FIG. In the same figure, the terminals of the current collector 96 of the counter electrode 92 are extended to the back side of the polypropylene plate-like member 992, and when the cover 22 is pressed toward the storage container 21 by the pressurizing means 1, the elastic member 10 holds the current collector terminal from above, and makes the counter electrode 92 and the lid portion 22 conductive.
[0020]
If the plate-like electrode body 9 is also housed using the hollow columnar member 4 for housing the electrode body in the same manner as the spiral-shaped electrode body 8, the positional deviation between the electrode members and the electrode and container 21 This is preferable because it is possible to avoid this contact.
[0021]
There is no restriction | limiting in particular in the constituent material of the electrode body in this invention, A various combination can be used. When evaluating a negative electrode material of an organic electrolyte battery, for example, a lithium ion battery, an electrode made of a negative electrode material such as a carbon-based material, for example, natural graphite, amorphous carbon, etc. Alternatively, a positive electrode material such as a lithium transition metal compound, manganese dioxide, or fluorinated graphite is used, and a lithium metal foil, carbon, or the like is used for the counter electrode 82 and the reference electrode 83. As the separator 84, a nonwoven fabric made of glass fiber or a polyolefin microporous film such as polyethylene can be used. In the case of an aqueous battery, a Ni-Cd battery system using nickel hydroxide as the working electrode 81 and cadmium hydroxide as the counter electrode 82, or an aqueous capacitor using activated carbon for the working electrode 81 and the counter electrode 82 can be configured. . Current collectors are stainless steel (austenitic, ferritic, etc.), steel, aluminum, copper, nickel, titanium, carbon mesh, foil, etc. A material free from corrosion, reaction, and dissolution can be selected as appropriate.
[0022]
In addition, when gas is generated inside the cell and the pressure in the cell becomes high, a safety mechanism, for example, a hole is made to penetrate a part of the lid portion 22, and Al-PET, Al-PP, etc. It is preferable to provide a safety valve or a pressure valve in which the resin surface of the laminate film is placed in contact with the lid portion 22 and the hole is closed by hot pressing.
[0023]
Examples of the present invention are shown below.
Example 1
In an argon box, an electrochemical cell containing the following lithium ion battery was assembled. Put a 5mm thick phenolic resin molded board in a siliconit electric furnace, raise the temperature to 500 ° C at a rate of 50 ° C / hour in a nitrogen atmosphere, and further raise the temperature to 650 ° C at a rate of 10 ° C / hour. The polyacene (PAS) synthesized by heat treatment was pulverized by a disk mill to obtain a powder having an average particle size of about 7 μm. The H / C ratio of this PAS powder was 0.22. Next, 100 parts by weight of the PAS powder, 10 parts by weight of acetylene black, and 10 parts by weight of polyvinylidene fluoride powder were sufficiently mixed with 120 parts by weight of N-methylpyrrolidone to obtain a slurry. The slurry was applied to one side of a 20 μm thick copper foil and pressed to obtain a PAS working electrode 91 having a thickness of 110 μm. This was cut into a size of 15 × 20 mm and overlaid on the SUS mesh current collector 95.
The reference electrode 93 was prepared by press-bonding lithium metal having a thickness of 200 μm and a size of 15 × 20 mm on a SUS mesh current collector 97. The counter electrode 92 was prepared by press-bonding metal lithium having a thickness of 200 μm and a size of 15 × 20 mm on a SUS mesh current collector 96.
As an electrolytic solution, a solution in which lithium hexafluorophosphate (LiPF ₆ ) was dissolved in propylene carbonate at a concentration of 1 mol / l was used. As the separator 94, a felt made of glass fiber was used. The current collectors 95 and 97 are respectively fixed to both surfaces of a 2 mm-thick polypropylene electrical insulating layer 991, and the SUS mesh current collector 96 is connected from one side of a 5 mm-thick polypropylene plate 992 to its back surface. Bent.
A separator 94 is laid on the bottom of the electrode container 21, and a reference electrode 93 and a polypropylene plate 991 with a lithium metal surface on the lower side, a PAS working electrode 91 with a copper foil surface on the lower side, a separator 94 and a lithium metal surface. The counter electrode 92 and the 5 mm-thick polypropylene plate-like member 992 were laminated in this order. After connecting the current collector 95 of the working electrode 91 to the external terminal 51, the spacer 6 made of polypropylene and the O-ring 7 made of butyl rubber are placed on the upper end of the electrode storage container 21, the body portion 23 is overlapped, and the current collector of the reference electrode 93 is placed. 97 was connected to the external terminal 53. Next, the laminated body of the electrode storage container 21 and the body portion 23 was put in the outer case 3, the electrolytic solution was injected, the bell jar was applied, and the separator 94 and the working electrode 95 were sufficiently impregnated with the electrolytic solution under reduced pressure.
Next, the spacer 6 made of polypropylene and the O-ring 7 made of butyl rubber are placed on the upper end of the body portion 23, the SUS winding spring 10 is placed on the polypropylene plate-like member 992, and the lid portion 22 is placed on the top. Then, it was compressed downward with the hand press 1 and brought into close contact with the upper end of the body portion 23.
The assembly of the electrochemical cell took only about 5 minutes even in an argon box with poor workability, and could be easily performed.
[0024]
Comparative Example 1
Using the same electrode body as in the example, an electrochemical cell of a type that fixes four points with screws was assembled. It was difficult to match the four screw holes of the electrode container and the lid, and the assembly took 10 minutes or more.
[0025]
Example 2
A cylindrical lithium ion battery was prepared. LiCoO ₂ was applied to both surfaces of the aluminum foil, and an aluminum lead 821 was ultrasonically welded to the non-coated portion to prepare a counter electrode (positive electrode) 82. Working electrode (negative electrode) 81 was prepared by applying graphite on both sides of the copper foil and ultrasonically welding nickel lead 811 to the non-coated portion. The working electrode 8 1 and the counter electrode 82 were overlapped and wound via a separator 83 to obtain a spiral electrode 8.
A tubular polypropylene hollow columnar member 4 is inserted into the storage container 21, a spiral electrode 8 is inserted therein, and a nickel lead 811 is disposed between the bottom of the storage container 21 and the lower end surface of the hollow columnar member 4. The nickel lead 811 is electrically connected to the storage container 21 by pressing the hollow columnar member 4. On the other hand, the aluminum lead 821 is sandwiched between the winding spring 10 and the upper end surface of the hollow columnar member 4 by pressing the lid portion 22 as shown in FIG. 22 was bent to be electrically connected. After the electrode storage container 21 is inserted into the outer case 3, the same electrolytic solution as in Example 1 is injected, and the working electrode 81, the counter electrode 82, and the separator 83 are sufficiently impregnated with the electrolytic solution under a reduced pressure by covering with a bell jar, and then hollow. The winding spring 10 is placed on the aluminum lead 811 on the upper end surface of the columnar member 4, and the lid portion 22 is further placed thereon, and is pushed downward by the hand press 1, and the lid portion 22 is brought into close contact with the upper end of the storage container 21. A cell for evaluation of a type battery was obtained.
Ten assemblies were assembled. All of the batteries were good except for one that failed to be wound up due to electrode winding failure. The assembly time per piece was about 40 minutes.
[0026]
Comparative Example 2
A spiral electrode similar to that in Example 2 was placed in an outer can, and a nickel lead as a negative electrode was resistance-welded to the bottom of the can to neck the top of the can. Next, after mounting a gasket on the top of the can, the positive electrode aluminum lead was ultrasonically welded to the top cap. After injecting the electrolytic solution, it was caulked into a top cap and a can to obtain a cylindrical battery. This assembly was done 10 times, but there were 3 lead welding defects, 2 liquid leaks, 1 winding failure, 2 things that could not be inserted into the winding, and finally it became a battery. Was two. The assembly time per piece was about 1 hour.
[0027]
【The invention's effect】
The electrochemical cell of the present invention is easy to assemble by using the pressurizing means, and the battery members are contacted uniformly. Further, since the disassembly is easy, the exchange of the electrodes can be easily performed.
[0028]
[Brief description of the drawings]
FIG. 1 is a perspective view of one embodiment of an electrochemical cell of the present invention.
FIG. 2 is a cross-sectional view of one embodiment of an electrochemical cell body in the present invention.
FIG. 3 is a cross-sectional view of another embodiment of an electrochemical cell body according to the present invention.
FIG. 4 is a perspective view of a spiral electrode body in the present invention.
FIG. 5 is a cross-sectional view showing a state in which a spiral electrode body is housed in an electrochemical cell.
FIG. 6 is a cross-sectional view of one embodiment of a plate electrode body in the electrochemical cell of the present invention.
FIG. 7 is a cross-sectional view of another embodiment of the plate electrode body in the electrochemical cell of the present invention.
FIG. 8 is a cross-sectional view showing a state where a plate electrode body is housed in an electrochemical cell.
9 is an enlarged cross-sectional view of the plate electrode body in FIG.
[0029]
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Pressurization means 2 Electrochemical cell main body 21 Electrode storage container 22 Lid part 23 Body part 3 Outer case 4 Hollow columnar member 51-53 External terminal
511 and 531 Lead fixing jig 6 Spacer 7 O-ring 8 Spiral electrode body 81 Working electrode 82 Counter electrode 83 Separator 85 and 86 Current collector 811 Working electrode lead 821 Counter electrode lead 9 Plate electrode body 91 Working electrode 92 Counter electrode 93 Reference Pole 94 Separator 95-97 Current collector
911 and 912 working electrode
921 and 922 counter electrode
991 Electrical insulating layer
992 Plate member 10 Elastic member

Claims

Electrode body formed by oppositely arranged with the separator at least one set of working electrode and the counter electrode, the storage container and the electrochemical cell consisting of a lid portion of the container for accommodating the electrode body, the area of the lid portion electrochemical characterized by substantially further comprising a pressing means comprising a pressing surface of the same area, that said container by substantially the whole surface of the lid portion by the pressing surface for pressing on the container side is sealed when cell.

2. The electrochemical cell according to claim 1, wherein the pressurizing means is a hand press or a vise.

3. The electrochemical cell according to claim 1, wherein the electrode body further includes at least one reference electrode, and has at least one body portion between the storage container and the lid portion.

The electrochemical cell according to claim 1, wherein the electrode body is a spiral electrode body.

The storage container further includes a hollow columnar member made of an electrically insulating material for storing the spiral electrode body, and a conductive material is formed between the upper end surface of the hollow columnar member and the lid portion. And pressing one of the leads of the electrode body against the elastic member on the upper end surface of the hollow columnar member by pressing the lid portion toward the storage container by the pressing means. 5. The electrochemical cell according to claim 4, wherein the other lead of the electrode body is brought into contact with the bottom of the storage container below the lower end surface of the hollow columnar member.

The electrode body has a plate-like structure, and further includes an elastic member between the electrode body and the lid portion, and the elastic body is pressed by pressing the lid portion toward the storage container by the pressurizing means. The electrochemical cell according to any one of claims 1 to 3, wherein the working electrode, the separator, and the counter electrode are in contact with each other via a member.

The elastic member is made of a conductive material, and the elastic member is brought into contact with one of the leads of the electrode body by pressing the lid portion toward the storage container by the pressing means. The electrochemical cell according to claim 6.

The electrochemical cell according to claim 5, wherein the elastic member is a wound spring.