JP2004266091A - Film type storage device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact film type storage device wherein the exposed portion of a connection terminal has a high durability. <P>SOLUTION: The storage device comprises a storage body having at least one pair of positive and negative electrodes, outer-packaging films for covering and sealing the storage body, and external connection terminals of the positive and negative electrodes. Sealing is performed by overlapping at least parts of the outer-packaging films. The connection terminals of the positive and negative electrodes are extracted outside between the overlapping parts of the outer-packaging films. The exposed portions of the connection terminals exposed outside are divided into a plurality of parts, with one part of the divided exposed portion of each electrode being located on one face of the sealed section and the other part located on the other face of the sealed section. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

（ここで、ｘ及びｙはそれぞれ独立に、０、１または２である）
で表されるメチレン・ビスフェノール類であることができ、あるいはヒドロキシ・ビフェニル類、ヒドロキシナフタレン類であることもできる。これらの中でも、実用的にはフェノール類、特にフェノールが好適である。
【００５０】
また、上記芳香族系縮合ポリマ−としては、上記のフェノール性水酸基を有する芳香族炭化水素化合物の１部をフェノール性水酸基を有さない芳香族炭化水素化合物、例えばキシレン、トルエン、アニリン等で置換した変成芳香族系縮合ポリマー、例えばフェノールとキシレンとホルムアルデヒドとの縮合物を用いることもできる。更に、メラミン、尿素で置換した変成芳香族系ポリマーを用いることもでき、フラン樹脂も好適である。
【００５１】
上記アルデヒドとしては、ホルムアルデヒド、アセトアルデヒド、フルフラール等のアルデヒドを使用することができ、これらの中でもホルムアルデヒドが好適である。また、フェノールホルムアルデヒド縮合物としては、ノボラック型またはレゾール型あるいはこれらの混合物のいずれであってもよい。
【００５２】
上記不溶不融性基体は、上記芳香族系ポリマーを熱処理することにより得られるものであり、特公平１−４４２１２号公報、特公平３−２４０２４号公報等に記載されているポリアセン系骨格構造を有する不溶不融性基体は、すべて用いることができる。
【００５３】
本発明に用いる不溶不融性基体は、例えば次のようにして製造することもできる。すなわち、上記芳香族系縮合ポリマーを、非酸化性雰囲気下（真空も含む）中で４００〜８００°Ｃの適当な温度まで徐々に加熱することにより、水素原子／炭素原子の原子比（以下Ｈ／Ｃと記す）が０．５〜０．０５、好ましくは０．３５〜０．１０の不溶不融性基体を得ることができる。
【００５４】
また、特公平３−２４０２４号公報等に記載されている方法で、６００ｍ^２／ｇ以上のＢＥＴ法による比表面積を有する不溶不融性基体を得ることもできる。例えば、芳香族系縮合ポリマーの初期縮合物と無機塩、例えば塩化亜鉛を含む溶液を調製し、該溶液を加熱して型内で硬化する。
【００５５】
かくして得られた硬化体を、非酸化性雰囲気下（真空も含む）中で、３５０〜８００°Ｃの温度まで、好ましくは４００〜７５０°Ｃの適当な温度まで徐々に加熱した後、水あるいは希塩酸等によって充分に洗浄することにより、上記Ｈ／Ｃを有し、かつ例えば６００ｍ^２／ｇ以上のＢＥＴ法による比表面積を有する不溶不融性基体を得ることもできる。
【００５６】
本発明に用いる不溶不融性基体は、Ｘ線回折（ＣｕＫα）によれば、メイン・ピークの位置は２θで表して２４°以下に存在し、また該メイン・ピークの他に４１〜４６°の間にブロードな他のピークが存在するものである。すなわち、上記不溶不融性基体は、芳香族系多環構造が適度に発達したポリアセン系骨格構造を有し、かつアモルファス構造をとると示唆され、リチウムを安定にドーピングすることができることから、リチウム蓄電装置用の活物質として有用である。
【００５７】
本発明における正極あるいは負極電極は、粉末状、粒状、短繊維状等の成形しやすい形状にある正極あるいは負極活物質をバインダーで成形したものとすることが好ましい。バインダーとしては、例えばＳＢＲ等のゴム系バインダーやポリ四フッ化エチレン、ポリフッ化ビニリデン等の含フッ素系樹脂、ポリプロピレン、ポリエチレン等の熱可塑性樹脂を用いることができ、これらの中でもフッ素系バインダーを用いることが好ましい。特に、フッ素原子／炭素原子の原子比（以下、Ｆ／Ｃと記す）が１．５未満０．７５以上であるフッ素系バインダーを用いることが好ましく、１．３未満０．７５以上のフッ素系バインダーを用いることが更に好ましい。
【００５８】
上記フッ素系バインダーとしては、例えばポリフッ化ビニリデン、フッ化ビニリデン−３フッ化エチレン共重合体、エチレン−４フッ化エチレン共重合体、プロピレン−４フッ化エチレン共重合体等が挙げられ、更に主鎖の水素をアルキル基で置換した含フッ素系ポリマーも用いることができる。
【００５９】
上記ポリフッ化ビニリデンの場合、Ｆ／Ｃは１であり、フッ化ビニリデン−３フッ化エチレン共重合体の場合、フッ化ビニリデンのモル分率が５０％のとき、８０％のとき、それぞれＦ／Ｃは１．２５、１．１となる。更に、プロピレン−４フッ化エチレン共重合体の場合、プロピレンのモル分率が５０％のとき、Ｆ／Ｃは０．７５となる。これらの中でも、ポリフッ化ビニリデン、フッ化ビニリデンのモル分率が５０％以上のフッ化ビニリデン−３フッ化エチレン共重合体が好ましく、実用的にはポリフッ化ビニリデンが好ましく用いられる。
【００６０】
また、上記正極あるいは負極活物質に、必要に応じてアセチレンブラック、グラファイト、金属粉末等の導電材を適宜加えてもよい。導電材の混合比は、上記活物質の電気伝導度、電極形状等により異なるが、活物質に対して２〜４０％の割合で加えることが適当である。
【００６１】
本発明の蓄電装置おいて、電解質部は、電解質と電解質を溶解可能な媒体により構成され、より具体的には、電解質を溶媒に溶解させた電解液などとして構成される。電解液を構成する溶媒として好ましくは、例えば、非プロトン性有機溶媒が採用される。この非プロトン性有機溶媒としては、例えばエチレンカーボネート、プロピレンカーボネート、ジメチルカーボネート、ジエチルカーボネート、γ−ブチロラクトン、アセトニトリル、ジメトキシエタン、テトラヒドロフラン、ジオキソラン、塩化メチレン、スルホラン等が挙げられる。更に、これら非プロトン性有機溶媒の二種以上を混合した混合液を用いることもできる。
【００６２】
また、上記の単一あるいは混合の溶媒に溶解させる電解質は、リチウムイオンを生成しうる電解質であれば、あらゆるものを用いることができる。このような電解質としては、例えばＬｉＩ、ＬｉＣｌＯ_４、ＬｉＡｓＦ_６、ＬｉＢＦ_４、ＬｉＰＦ_６等が挙げられる。
【００６３】
上記の電解質および溶媒は、充分に脱水された状態で混合され、電解液とするのであるが、電解液中の電解質の濃度は、電解液による内部抵抗を小さくするため少なくとも０．１モル／ｌ以上とすることが好ましく、０．５〜１．５モル／ｌの範囲内とすることが更に好ましい。
【００６４】
【発明の実施の形態】
以下、本発明の実施の形態について、図面を参照しながらより詳細に説明する。図１から図６には、外装フィルム（４）および（５）で蓄電体等の内容物を覆い密封した蓄電装置であり、蓄電装置の左側端および右側端にそれぞれ接続端子が設けられた例である。図１は、フィルム型蓄電装置の斜視図であり、図２は正面図であり、図３は左側面図であり、図４は平面図である。図５は、図４に示されたＩ−Ｉ’線に沿う断面を示す図であり、図６は、外装フィルム（４）を透視してみた底面図である。なお、図６においては、外装フィルム（４）の表面上の正極端子（１ｂ）および負極端子（２ｂ）の表示は省略している。
【００６５】
図１から図６に示す例では、外装フィルム（４）および（５）はそれぞれ周縁部の四方を熱融着されシール部が形成される（図６中のＣ）。正極端子（１ｂ）はシール部の左側端に、負極端子（２ｂ）はシール部の右側端に配置されている。図２から図４に示されるように、外部への露出部がシート状に形成されている正極端子（１ｂ）および負極端子（２ｂ）はそれぞれ、シール部の上面および下面に配置されている。したがって、接続端子は従来のように突出しておらず、端子の突出分をなくしただけコンパクトな蓄電装置となる。また、露出部が、外装フィルムの面上に位置し、外装フィルムのシール部を上下から挟み込む状態になっている。したがって、正極端子（１ｂ）および負極端子（２ｂ）の露出部を、外部からのはさみ型の端子で接続する様な場合、従来のように薄い端子のみを挟んで接続するのに比べより安定した状態で接続可能である。また、従来のように接続端子の外装フィルムの間どうしから現れる部分、すなわち、接続端子の基端に過剰に負荷がかかることがないため、接続端子は破損しにくく、接続端子の耐久性が高い。
【００６６】
図５は、図４に示すＩ−Ｉ線に沿う断面図である。正極端子（１ｂ）を例に、接続端子の構成についてさらに説明する。本例における正極端子（１ｂ）は、２枚の金属箔を重ね合わせて構成されている。正極端子（１ｂ）は外装フィルム（４）の内面に融着されているが、例えばシーラントフィルムを介して融着しても良い。正極端子（１ｂ）は、外装フィルム（４）および外装フィルム（５）の間からセル内部からセル外部へと出て露出部を形成する。正極端子（１ｂ）を構成する上下２枚のシートの露出部はそれぞれ折り返され、上側のシートが外装フィルム（４）の面上に、下側のシートが外装フィルム（５）の面上に、それそれ配置して固定される。２枚の正極端子（１ｂ）はセル内部の正極集電体の端子溶接部にいずれも溶接されており、正極端子と外装フィルムの熱融着部（Ａ）において２枚の正極端子（１ｂ）の間にもシーラントフィルムを挟み込み、熱融着の際端子同士の接着を行っている（図示せず）。ただし、２枚の正極端子（１ｂ）がセル内部では例えば超音波溶接により密着され１枚になっていれば上述のシーラントフィルムを用いなくても良い。正極端子（１ｂ）を構成するそれぞれのシートを２つに分けて折り返すという、処置として簡便な手法により、耐久性が高く、安定した接続が可能な端子が形成される。
【００６７】
続いて、図１から図６で示される例の他の構成について説明する。本例では、外装フィルム（５）に正極（１）、負極（２）およびセパレータ（３）などで構成される蓄電体の厚み分のエンボス成形を施しているが、外装フィルム（４）、（５）のいずれか、または両方にエンボス成形を施しても構わない。
【００６８】
図５に示すように、正極集電体（１ａ）の両面に成形された正極（１）と負極集電体（２ａ）の両面に成形された負極（２）とは、セパレーター（３）を介し積層されている。このセパレーター（３）は、電解液あるいは電極活物質等に対して耐久性のある連通気孔を有する電子伝導性のない多孔体等からなり、通常はガラス繊維、ポリエチレンあるいはポリプロピレン等からなる布、不織布あるいは多孔体が用いられる。セパレーター（３）の厚みは、キャパシタの内部抵抗を小さくするために薄い方が好ましいが、電解液の保持量、流通性、強度等を勘案して適宜設定することができる。
【００６９】
そして、セパレーター（３）には電解液が含浸されており、該電解液には、正極および負極に担持されうるイオンを生成しうる後述の化合物が非プロトン性有機溶媒に溶解されている。電解液は、通常液状であってセパレーター（３）に含浸されるが、漏液を防止するためゲル状または固体状の電解質を用い、セパレーター（３）を用いない場合もある。
【００７０】
上記正極集電体（１ａ）および負極集電体（２ａ）は、それぞれが表裏面を貫通する孔（図示せず）を備えていても良く、それぞれにセルの正極端子（１ｂ）および負極端子（２ｂ）が接続されている。
【００７１】
以下、さらに他の例を順次説明していくが、それぞれ特徴部分を中心に説明し、同様の構成については説明を省略する。
【００７２】
図７は、本発明の他の例を示すものであり、図７には要部のみを示している。図７に示す例では、正極端子（１ｂ）および負極端子（２ｂ）が、同一辺に設置されている。同一辺に正極端子（１ｂ）および負極端子（２ｂ）を設けるようにすることにより、セル内部における集電体と接続端子をつなぐためのスペースを一辺側にのみ設ければよいため、正極などで構成される蓄電体の容積を大きく取ることが可能である。
【００７３】
図８から図１１には、本発明のさらに別の例を示す。本例では、負極端子（２ｂ）を例として説明する。図８は、負極端子側を示した斜視図であり、図９は、負極端子側の右側面図であり、図１０は負極端子部分の断面図である。図８から図９はそれぞれ要部のみ示している。また、図１１は、負極端子（２ｂ）の斜視図である。
【００７４】
上記の２つの例では、接続端子は２枚のシートを重ねれて形成されていた。図８から図１１で示す例は、１枚のシートを左右に２つに分けて用いている。図１１に示すように、負極端子（２ｂ）は、右辺に長手方向の切り込みが入れられて、左右に、すなわち水平方向に分割されている。切り込みは露出部に対応する長さ分だけ入れられている。分割された一方の部位は上方へ反転して折り曲げられ、分割された他方の部位は下方に反転して折り曲げられる。図１０、図１１に示されるように、上方に反転して折り曲げられた部位は外装フィルム（４）の面上に例えば両面テープ等により固定され、下方に反転して折り曲げられた部位は外装フィルム（５）の面上に例えば両面テープ等により固定される。
【００７５】
図８から図１１で示される例は、接続端子の露出部を水平方向に複数に分割して折り曲げるという簡便な処理で、接続端子の耐久性向上、外部からの端子との安定した接続などの効果が得られる。
【００７６】
図１２から図１４および図１５から図１７は、本発明の他の実施形態として、角型電池等に用いるような巻き込み型構造をとるキャパシタの電極配置の例を示している。図１３は図１２のＩＶ−ＩＶ’線に沿った断面図であり、図１４は図１３のＩ−Ｉ’線に沿った断面図である。また、図１６は図１５のＩ−Ｉ’線に沿った断面図であり、図１７は図１５のＩＶ−ＩＶ’線に沿った断面図である。
【００７７】
図１２から図１７に示される２例において用いられる電極捲回ユニットは、リボン状の正極、負極をセパレータを介して楕円状に捲回した後にプレス成形したものである。これらの電極配置において、正極（１）および負極（２）は、それぞれ集電体上に成形されている。
【００７８】
図１２から図１５で示される例は、シート状の正極、負極、および各集電体を重ねこれを捲回して得られる、巻き込み型構造を有する電極捲回ユニットを形成する場合であって、電極捲回ユニットの中心に板状のリチウム金属（７）が設けられる例を示すものである。なお、各シートが捲き合わされて形成される積層部分を、電極捲回ユニットの積層部分という。リチウム集電体（７ａ）が２枚のリチウム金属（７）に挟まれて設けられている（図１３）。図１２から図１５に示すように、負極集電体（２ａ）はそれぞれのシートの最外周部の負極端子側に、負極端子と接続するための引き出し部が、電極捲回ユニットの積層部分から突出して設けられている（図１４では、概要を示すために電極捲回ユニットの積層部分において、各集電体を示し正極、負極等は省略している）。
【００７９】
また、リチウム極集電体（７ａ）も負極端子と接続するための引き出し部が、積層部から突出する形態で設けられている。また、正極集電体（１ａ）も電極捲回ユニット（９）の積層部分から正極端子側にはみ出すように引き出し部が形成されており、この引き出し部が正極端子上面に誘導されて正極端子と接続されている。
【００８０】
図１５から１７で示される例では、捲回体の最外周となるセパレーター（３）の外周にリチウム金属（７）を貼り付けてある（図１６）。図１５に示すように、リチウム集電体（７ａ）および負極集電体（２ａ）は、それぞれのシート状のものが負極端子側にはみ出すように他の層部材とずらして重ね合わせて捲回され、電極捲回ユニットの積層部分からはみ出した引き出し部が形成されており、リチウム極集電体（７ａ）および負極集電体（２ａ）はそれぞれ負極端子の上面において接続されている。また、正極集電体（１ａ）も、電極捲回ユニットの積層部分から正極端子側にはみ出した引き出し部が形成されており、この引き出し部が正極端子上面に誘導されて正極端子と接続されている。
【００８１】
図１２から図１７にそれぞれ示される例においては、負極とリチウムとを、ニッケル、銅、ステンレス等の導電物質を介し、あるいは負極集電体上にリチウムを貼り付けることにより接触させているが、本発明の上記〔５〕、〔６〕に係る有機電解質キャパシタは、特にこの構造に限定されるものではなく、例えばリチウムを直接負極上に貼り付けることにより接触させてもよい。すなわち、セル組立て時、電解液を注入した際に、すべての負極とリチウムが電気化学的接触し、電解液を介してリチウムが負極活物質に担持されるように配置されていればよい。
【００８２】
リチウム金属集電体としてステンレスメッシュ等の導電性多孔体を用い、この導電性多孔体の気孔部にリチウム金属の８０％以上を充填して配置することにより、リチウムが担持されても、リチウムの消失による電極間に生じる隙間が少なくなり、リチウムが負極活物質にスムーズに担持されることとなる。
【００８３】
一方、リチウム金属を負極板の断面方向に配置し、セル内にて負極とリチウム金属とを電気化学的接触させて負極活物質にリチウムを担持させることも可能であるが、この場合電極の幅が長いと電極内でのドープむらが大きくなるので、セル構成、電極サイズ等を考慮し配置するリチウムの位置を選択することが望ましい。
【００８４】
本発明の一実施形態であるリチウム極を有する有機電解質キャパシタにおいては、負極に担持させるリチウムを特定位置に局所的に配置することにより、セル設計上の自由度および量産性の向上を可能とするとともに、優れた充放電特性を有するものとしている。
【００８５】
この有機電解質キャパシタにおいて、負極に担持されるリチウム量は、使用する負極材、有機電解質キャパシタに求める特性により都度決定することができる。
【００８６】
図１８および図１９は、積層用電極集電体の端子溶接部の形状と積層方向を示した展開斜視図である。図１８の例では、正極端子と負極端子が逆方向になる積層方向であり、図１９の例では、同じ方向になる積層方向である。ただし、正極と負極の端子の方向はこの２種類に限定されるものではない。
【００８７】
図２０から図２２には、リチウム極を有する有機電解質キャパシタの他の実施形態であって、セル内にリチウムを配置し、複数組の正極板、セパレーター、負極板を順次積層してなる、実施形態をそれぞれ示している。
【００８８】
図２０は、上記タイプのキャパシタのセル内における電極配置の一例を示している。この図に示すように、負極集電体（２ａ）の両面に成形された負極（２）と、ステンレスメッシュ、銅エキスパンドメタル等のリチウム金属集電体（７ａ）に圧着されたリチウム金属（７）とが導線（８ａ）により接続されており、リチウム金属（７）は、積層ユニットの下部に配置されている。
【００８９】
負極集電体（２ａ）とリチウム金属集電体（７ａ）は直接溶接することもできる。また、正極集電体（１ａ）の両面に成形された正極（１）と上記負極（２）とは、セパレーター（３）を介し積層されている。
【００９０】
上記負極集電体（２ａ）および正極集電体（１ａ）は、それぞれが表裏面を貫通する孔（図示せず）を備えており、それぞれにセルの負極端子および正極端子に接続されている。
【００９１】
図２１は、上記キャパシタのセル内における電極配置の他の例を示している。このキャパシタにおいては、リチウム金属集電体（７ａ）に圧着されたリチウム金属（７）を、積層ユニットの上部および下部にそれぞれ配置している。
【００９２】
また、図２２に示す他の例では、リチウム金属（７）を積層ユニットの真中に配置している。図２０から２２に例示されるように、積層タイプの電極配置においては、リチウム金属（７）の配置位置を上記の例のように適宜変更することができる。
【００９３】
【実施例】
実施例１〜３、比較例１
（負極の製造法）
厚さ０．５ｍｍ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５００℃まで５０℃／時間の速度で、更に１０℃／時間の速度で６５０℃まで昇温し、熱処理し、ＰＡＳを合成した。かくして得られたＰＡＳ板をディスクミルで粉砕することにより、ＰＡＳ粉体を得た。このＰＡＳ粉体のＨ／Ｃ比は０．２２であった。
【００９４】
次に、上記ＰＡＳ粉体１００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とを充分に混合することによりスラリーを得た。該スラリーを厚さ４０μｍ（気孔率５０％）の銅エキスパンドメタル両面に塗工、乾燥し、プレス後２００μｍのＰＡＳ負極を得た。
【００９５】
（正極の製造法）
厚さ０．５ｍｍ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５００℃まで５０℃／時間の速度で、更に１０℃／時間の速度で６５０℃まで昇温し、熱処理し、ＰＡＳを合成した。このＰＡＳを水蒸気により賦活した後ナイロンボールミルで粉砕しＰＡＳ粉末を得た。該粉末のＢＥＴ法による比表面積値は１５００ｍ^２／ｇであり、元素分析により、そのＨ／Ｃは０．１０であった。
【００９６】
上記ＰＡＳ粉末１００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１００重量部に溶解した溶液とを充分に混合することによりスラリーを得た。該スラリーをカーボン系導電塗料をコーティングした厚さ４０μｍ（気孔率５０％）のアルミニウムエキスパンドメタル両面に塗工、乾燥し、プレス後３８０μｍのＰＡＳ正極を得た。
【００９７】
（負極の単位重量当たりの静電容量測定）
上記負極を１．５×２．０ｃｍ^２サイズに４枚切り出し、評価用負極とした。負極と対極として１．５×２．０ｃｍ^２サイズ、厚み２００μｍの金属リチウムを厚さ５０μｍのポリエチレン製不織布をセパレーターとして介し模擬セルを組んだ。参照極として金属リチウムを用いた。電解液としては、プロピレンカーボネートに、１モル／ｌの濃度にＬｉＰＦ_６を溶解した溶液を用いた。
【００９８】
充電電流１ｍＡにて負極活物質重量に対して４００ｍＡｈ／ｇ分のリチウムを充電し、その後１ｍＡにて１．５Ｖまで放電を行った。放電開始後１分後の負極の電位から０．２Ｖ電位変化する間の放電時間より負極の単位重量当たりの静電容量を求めたところ、６５３Ｆ／ｇであった。
【００９９】
（正極の単位重量当たりの静電容量測定）
上記正極を１．５×２．０ｃｍ^２サイズに３枚切り出し、一枚を正極、もう一枚を負極と参照極とした。正極、負極を厚さ５０μｍの紙製不織布をセパレーターとして介しキャパシタの模擬セルを組んだ。正極電解液としては、プロピレンカーボネートに、１モル／ｌの濃度にトリエチルメチルアンモニウム・テトラフルオロボレート（ＴＥＭＡ・ＢＦ４）を溶解した溶液を用いた。
【０１００】
充電電流１０ｍＡにて２．５Ｖまで充電しその後定電圧充電を行い、総充電時間１時間の後、１ｍＡにて０Ｖまで放電を行った。２．０Ｖ〜１．５Ｖ間の放電時間よりセルの単位重量当たりの静電容量を求めたところ２１Ｆ／ｇであった。また、参照極と正極の電位差より同様に正極の単位重量当たりの静電容量も求めたところ８５Ｆ／ｇであった。
【０１０１】
（電極積層ユニット１の作成）
厚さ２００μｍのＰＡＳ負極と、厚さ３８０μｍのＰＡＳ正極を図１８に示すような形状で電極面積がそれぞれ、５．０×７．０ｃｍ^２になるようにカットし、セパレータとして厚さ２５μｍのセルロース／レーヨン混合不織布を用いて、図１８に示したように正極集電体、負極集電体の接続端子との溶接部（以下「接続端子溶接部」という）がそれぞれ反対側になるよう配置し、正極、負極の対向面が１０層になるよう積層し、最上部と最下部はセパレータを配置させて４辺をテープ止めして電極積層ユニットを得た。尚、正極は５枚、負極は６枚用いており、図２４に示すように、外側の２枚の負極は両面に成形された上記負極の片側をはがしたのもを用いた。厚さは１２０μｍである。正極活物質重量は負極活物質重量の１．７倍である。リチウム金属としては、リチウム金属箔（８０μｍ、５．０×７．０ｃｍ^２）を厚さ８０μｍのステンレス網に圧着したものを用い、負極と対向するように電極積層ユニットの上下に２枚配置した。負極（片面２枚、両面４枚）とリチウムを圧着したステンレス網はそれぞれ溶接し、接触させ電極積層ユニット１を得た。
【０１０２】
（電極積層ユニット２の作成）
厚さ２００μｍのＰＡＳ負極と、厚さ３８０μｍのＰＡＳ正極を図１９に示すような形状で電極面積がそれぞれ、５．０×８．０ｃｍ^２になるようにカットし、図１９に示したように正極集電体、負極集電体の接続端子溶接部がそれぞれ同じ側になるよう配置した以外は、電極積層ユニット１の作成と同様にして電極積層ユニットを得た。正極活物質重量は負極活物質重量の１．７倍である。リチウム金属としては、リチウム金属箔（８０μｍ、５．０×８．０ｃｍ^２）を厚さ８０μｍのステンレス網に圧着したものを用い、負極と対向するように電極積層ユニット２の上下に２枚配置した。負極（片面２枚、両面４枚）とリチウムを圧着したステンレス網はそれぞれ溶接し、接触させ電極積層ユニット２を得た。
【０１０３】
（セル１の作成）
予めシール部分にシーラントフィルムを熱融着した巾１０ｍｍ、長さ３０ｍｍ、厚さ０．１ｍｍのアルミニウム製正極端子２枚の間に、上記電極積層ユニット１の正極集電体の端子溶接部（５枚）を挟み込み超音波溶接した。同様に、予めシール部分にシーラントフィルムを熱融着した巾１０ｍｍ、長さ３０ｍｍ、厚さ０．１ｍｍのニッケル製負極端子２枚の間に負極集電体の端子溶接部（６枚）を挟み込み超音波溶接し、３．５ｍｍ深絞りした外装フィルムの内部へ設置した。電解液としてエチレンカーボネート、ジエチルカーボネートおよびプロピレンカーボネートを重量比で３：４：１とした混合溶媒に、１モル／ｌの濃度にＬｉＰＦ_６を溶解した溶液を真空含浸させた後、外装ラミネートフィルムで覆い４辺を熱融着し、図５と同様に２枚の端子の露出部はそれぞれ上下に折り返され外装フィルムのシール部に両面テープにて固定することによりフィルム型キャパシタを５０セル組立てた。
【０１０４】
（セル２の作成）
図７に示すように、正極端子および負極端子が同一辺上に有ること以外はセル１と同様に、上記電極積層ユニット２を用いてフィルム型キャパシタを５０セル組立てた。
【０１０５】
（セル３の作成）
上記電極積層ユニット１の正極集電体の端子溶接部（５枚）に、予めシール部分にシーラントフィルムを熱融着した巾２０ｍｍ、長さ３０ｍｍ、厚さ０．１ｍｍのアルミニウム製正極端子１枚を超音波溶接した。同様に負極集電体の端子溶接部（６枚）に、予めシール部分にシーラントフィルムを熱融着した巾２０ｍｍ、長さ３０ｍｍ、厚さ０．１ｍｍのニッケル製負極端子１枚を超音波溶接し、３．５ｍｍ深絞りした外装フィルムの内部へ設置した。電解液としてエチレンカーボネート、ジエチルカーボネートおよびプロピレンカーボネートを重量比で３：４：１とした混合溶媒に、１モル／ｌの濃度にＬｉＰＦ_６を溶解した溶液を真空含浸させた後、外装ラミネートフィルムで覆い４辺を熱融着し、図８、図９と同様に端子の露出部を左右に分割しそれぞれ上下に折り返し外装フィルムのシール部に両面テープにて固定することによりフィルム型キャパシタを５０セル組立てた。
【０１０６】
（セル４の作成）
予めシール部分にシーラントフィルムを熱融着した巾１０ｍｍ、長さ３０ｍｍ、厚さ０．２ｍｍのアルミニウム製正極端子１枚の上に、上記電極積層ユニット１の正極集電体の端子溶接部（５枚）を載せ超音波溶接した。同様に、予めシール部分にシーラントフィルムを熱融着した巾１０ｍｍ、長さ３０ｍｍ、厚さ０．２ｍｍのニッケル製負極端子１枚の上に負極集電体の端子溶接部（６枚）を載せ超音波溶接し、３．５ｍｍ深絞りした外装フィルムの内部へ設置した。電解液としてエチレンカーボネート、ジエチルカーボネートおよびプロピレンカーボネートを重量比で３：４：１とした混合溶媒に、１モル／ｌの濃度にＬｉＰＦ_６を溶解した溶液を真空含浸させた後、外装ラミネートフィルムで覆い４辺を熱融することによりフィルム型キャパシタを５０セル組立てた。図２３に示されるように正極端子、負極端子はともに外装フィルムのシール部より外側に伸びた形状である。
【０１０７】
（セルの初期評価）
セル１〜４の組み立て後７日間目の内部抵抗、ショート確認、液漏れ確認を行った。液漏れ確認については、−１０℃と６０℃の温度で交互に各１時間放置させる熱衝撃テストを５０サイクル行った後に確認した。結果を表１に示した。ただし、内部抵抗は５０セルの平均値を示した。
【０１０８】
【表１】

【０１０９】
組立直後の内部抵抗、ショート数、液漏れ数に関しては、セル１から４において特に顕著な差は見られなかった。ただし、若干ではあるが同じ積層ユニット１を用いたセルにおいて、セル１（実施例１）及びセル３（実施例３）はセル４（比較例１）よりも内部抵抗が低い結果となった。これは、セル１に関しては正極端子、負極端子がそれぞれ２枚あるため、また、セル３に関しては端子巾が広いため電極の端子溶接部への溶接が容易且つ溶接面積が大きくなり接触抵抗が低く抑えられたことと、端子露出部がシール部に固定され安定していることから、より基端部分に近いところから測定装置の接続が可能になったためと考えられる。
【０１１０】
（セルの特性評価）
７日間室温にて放置後、ショート、液漏れの無かったセルを各１個分解したところ、セル１〜４いずれのセルもリチウム金属は完全に無くなっていたことから、負極活物質の単位重量当たりに６５０Ｆ／ｇの静電容量を得るためのリチウムが予備充電されたと判断した。負極活物質と正極活物質の単位重量当たりの静電容量比は７．６５となる。
【０１１１】
また、セル１〜４を各１０個それぞれ１０００ｍＡの定電流でセル電圧が３．３Ｖになるまで充電し、その後３．３Ｖの定電圧を印加する定電流−定電圧充電を１時間行った。次いで、１００ｍＡの定電流でセル電圧が１．６Ｖになるまで放電した。この３．３Ｖ−１．６Ｖのサイクルを繰り返し、３回目の放電においてセル容量および体積エネルギー密度（但し、ここでは、ラミネートフィルムの融着部及び端子露出部の体積は除く）を評価した結果を表２に示す。ただし、セル容量、体積エネルギー密度は１０セルの平均である。
【０１１２】
【表２】

【０１１３】
負極活物質の単位重量当たりの静電容量が正極活物質の単位重量当たりの静電容量の３倍以上を有し、且つ正極活物質重量が負極活物質重量よりも大きく、負極には予めリチウムを担持させた設計の有機電解質キャパシタは大きなエネルギー密度を有することがわかる。
【０１１４】
また、フィルム電池外形サイズが同じでも、端子の取り方により活物質の充填率が変わり容量、エネルギー密度に差が現れる。端子はセル２のように同方向にとる方がより高容量となり望ましい。
【０１１５】
（衝撃試験）
図２６に示すような試験具を用いて衝撃試験を行った。なお、図２６には比較例のユニット（１１０）を固定した様子を示す。セル１〜４各２０セルに対し厚さ１０ｍｍ、縦８０ｍｍ、横１２０ｍｍのベニヤ板（５００）上にて、正極端子及び負極端子をそれぞれ端子固定用受け板と端子固定用押え板の間に挟み、固定用ネジを締め付ける端子留め具（５０１）によりセルを固定した。その後、高さ１ｍから縦及び横方向への落下テストを５０回ずつ行った後、内部抵抗、ショート確認、液漏れ確認を行った。液漏れ確認については、−１０℃と６０℃の温度で交互に各１時間放置させる熱衝撃テストを５０サイクル行った後に確認した。結果を表３に示した。ただし、内部抵抗は２０セルの平均値を示した。
【０１１６】
【表３】

【０１１７】
比較例１（セル４）は内部抵抗の上昇と液漏れ発生数が実施例に比較して多くなった。これは落下によるシール部の緩みの発生及び、電極の端子溶接部と端子の溶接部の接触抵抗が衝撃により上昇したものと考えられる。
【０１１８】
（端子を考慮した４セル並列でのエネルギー密度比較）
セル１およびセル４を用い、それぞれのセルを４セル積層させた並列接続型の組セルを試作した。積層させた組セルの体積エネルギー密度を計算する際の体積は、機器への搭載等を考慮し、セル本体、ラミネートフィルムの融着部、端子露出部を含む最大幅と最大高さの積をセル面積の面積とし、その値と４セルの厚みの積を体積とした。実施例１のセル（セル１）は、比較例１のような端子の張り出しがなく、コンパクトな組セルを作ることが可能であったが、比較例１のセル（セル４）はセル外部に張り出ており、実施例１の組セルに対し体積が１５％大きくなった。したがって、体積エネルギー密度は実施例３の方が１５％高いことがわかった。
【０１１９】
【発明の効果】
本発明によれば、接続端子の露出部の耐久性が高いフィルム型蓄電装置を簡便に得ることができる。また、本発明により、フィルム型蓄電装置をよりコンパクトにすることができる。さらに、本発明によれば、接続端子の接触面を大きくとり接触部抵抗が低いフィルム型蓄電装置が提供される。
【図面の簡単な説明】
【図１】本発明に係る、接続端子についての第１の設置例を示す斜視図である。
【図２】図１で示される第１の設置例の正面図である。
【図３】図１で示される第１の設置例の左側面図である。
【図４】図１で示される第１の設置例の平面図である。
【図５】図４に示されるＩ−Ｉ’線に沿う断面を示す図である。
【図６】外装フィルム（４）を透視して見た底面図である。
【図７】本発明に係る、接続端子についての第２の設置例の要部を示す斜視図である。
【図８】本発明に係る、接続端子についての第３の設置例の要部を示す斜視図である。
【図９】図８に示す第３の設置例の左側面図の要部を示す図である。
【図１０】図８に示す第３の設置例の要部の断面を示す図である。
【図１１】図８に示す第３の設置例で用いられる接続端子の斜視図である。
【図１２】本発明に係る、セル内の電極等を捲回電極配置とした、第１の例を、外装フィルム（４）を透視して見た底面図である。
【図１３】図２１に示す例のＩ−Ｉ線に沿う断面を示す図である。
【図１４】図２１に示す例のＩＶ−ＩＶ線に沿う断面を示す図である。
【図１５】本発明に係る、セル内の電極等を捲回電極配置とした、第２の例を、外装フィルム（４）を透視して見た底面図である。
【図１６】図２４に示す例のＩ−Ｉ線に沿う断面を示す図である。
【図１７】図２４に示す例のＩＶ−ＩＶ線にう断面を示す図である。
【図１８】本発明に係る、セル内の積層用電極集電体の端子溶接部の形状と積層方向の第１の例を示す展開斜視図である。
【図１９】本発明に係る、セル内の積層用電極集電体の端子溶接部の形状と積層方向の第２の例を示す展開斜視図である。
【図２０】セル内の積層電極配置の一例を示す図である。
【図２１】セル内の積層電極配置の他の一例を示す図である。
【図２２】セル内の積層電極配置の他の一例を示す図である。
【図２３】従来のフィルム型電池内の正極端子、負極端子の形状及び配置の例を示す説明図である。
【図２４】図２０に示される例のＶＩＩ−ＶＩＩ線に沿う断面を示す図である。
【図２５】図２０に示される例のＶＩ−ＶＩ線に沿う断面を示す図である。
【図２６】衝撃試験用の試験具にセルの固定した様子を示す図である。（Ｉ）は平面（上面）図、（ＩＩ）は（Ｉ）の右側面図である。
【符号の説明】
１ 正極
２ 負極
１ａ 集電体（正極）
２ａ 集電体（負極）
１ｂ 正極端子
２ｂ 負極端子
１ｃリード線固定用ネジ部（正極）
２ｃリード線固定用ネジ部（負極）
１ｄ正極タブ
２ｄ負極タブ
３ セパレーター
４ 外装ラミネートフィルム
５ 外装ラミネートフィルム（深絞り）
６ 端子支持体
７ リチウム極
７ａ リチウム極集電体
７ｂ リチウム極リード端子（引き出し部）
８ 導線
８ａ 導線
１０ 本発明のフィルム型セルの積層ユニット
１１ 一般的なフィルム型セルの積層ユニット
１２ リード線
１３ ベニヤ板
１４ 端子固定用受け板
１５ 端子固定用押え板
１６ 固定用ネジ
１０１ 正極
１０２ 負極
１０１ａ 正極集電体
１０２ａ 負極集電体
１０１ｂ 正極端子
１０２ｂ 負極端子
１０３ セパレーター
１０４ 外装ラミネートフィルム
１０５ 外装ラミネートフィルム（深絞り）
１１０ 従来のフィルム型セル
５００ ベニヤ板
５１０ 端子留め具
Ａ 正極端子と外装フィルムの熱融着部
Ｂ 負極端子と外装フィルムの熱融着部
Ｃ 外装フィルムの熱融着部
Ａ’正極集電体の端子溶接部と正極端子の溶接部（表面）
Ａ’’正極集電体の端子溶接部と正極端子の溶接部（裏面）
Ｂ’負極集電体の端子溶接部と負極端子の溶接部（表面）
Ｂ’’負極集電体の端子溶接部と負極端子の溶接部（裏面）
Ｅ 正極端子または負極端子と外装ラミネートフィルムの熱融着部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a film-type power storage device covered with a film, and more particularly to a compact film-type power storage device having high durability of connection terminals.
[0002]
[Prior art]
In recent years, secondary batteries using conductive polymers, transition metal oxides, etc. as the positive electrode and lithium metal or lithium alloy for the negative electrode have been used as alternatives to Ni-Cd batteries and lead batteries due to their high energy density. Proposed.
[0003]
However, when these secondary batteries are repeatedly charged and discharged, the capacity is greatly reduced due to deterioration of the positive electrode or the negative electrode, and there remains a problem in practical use. In particular, the deterioration of the negative electrode is accompanied by the formation of moss-like lithium crystals called dentite, and the repetition of charge and discharge eventually causes the dentite to penetrate the separator, causing a short circuit inside the battery, and in some cases, the battery In some cases, there was a problem in terms of safety, such as bursting.
[0004]
Therefore, in order to solve the above problems, a carbon material such as graphite is used for the negative electrode, and LiCoO 2 is used for the positive electrode. ₂ A battery using a lithium-containing metal oxide such as described above has been proposed. This battery is a so-called rocking chair type battery in which lithium is supplied from the lithium-containing metal oxide of the positive electrode to the negative electrode by charging after the battery is assembled, and the negative electrode lithium is returned to the positive electrode in discharging. Since only lithium ions are involved in charging and discharging without using a lithium battery, this is called a lithium ion secondary battery and is distinguished from a lithium battery using metallic lithium. This battery is characterized by having high voltage, high capacity, and high safety.
[0005]
As described above, lithium-ion secondary batteries have been studied as high-capacity and powerful power sources, and have been put to practical use mainly as main power sources for notebook computers and mobile phones. Above all, mobile phones have become smaller and lighter, and lithium-ion secondary batteries used as main power sources have also been required to be thinner and lighter. As a result, the outer case of the prismatic battery has been changed from iron to aluminum, and the weight has been significantly reduced. Further, as the thickness of the battery is required to be as thin as 4 mm or 3 mm, adoption of a film type battery using an aluminum laminate film as an exterior material is accelerated.
[0006]
In addition, as environmental issues are highlighted, renewable energy storage systems using solar power and wind power, distributed power sources for power load leveling, and power sources for electric vehicles instead of gasoline vehicles ( (Main power supply and auxiliary power supply) are being actively developed. Until now, lead-acid batteries have been used as power sources for electrical equipment in automobiles, but recently, in-vehicle devices and equipment such as power windows and car stereos have become more sophisticated and sophisticated, and energy density and output density have been reduced. From this point, a new power source is required. In these large batteries, in addition to the conventional cylindrical type and square type, a laminate film type aiming at further weight reduction and compactness is being developed. Such a shape is effective for space saving because it is hard to restrict the place where batteries are placed when it must be installed in a limited space such as a road conditioner installed at home or a car. There is a study for practical application.
[0007]
As described above, needs for film-type batteries and capacitors are increasing. Generally, a film-type battery uses a three-layer laminate film having a nylon film on the outside, an aluminum foil at the center, and an adhesive layer of modified polypropylene or the like on the inside as an exterior material. In general, the laminated film is deep drawn according to the size and thickness of the electrodes etc. that enter inside, and a unit in which the positive electrode, negative electrode and separator are laminated or wound is installed, and the electrolyte is injected. After that, the two laminated films are sealed by heat fusion or the like. At that time, a positive electrode terminal (mainly an aluminum foil having a thickness of several tens to several hundreds of μm) and a negative electrode terminal (mainly a nickel foil having a thickness of several tens to several hundreds of μm) come out of the battery from between the laminated films. The sealing of the laminated film is performed by fusing while sandwiching the positive electrode terminal and the negative electrode terminal. In order to achieve a sufficient sealing state, as described above, a thin metal foil is used as a terminal, an etching process is performed on the terminal surface, and a sealant film is applied in advance.
[0008]
23 to 25 show a conventional general structure. The positive electrode lead terminal (101b) and the negative electrode lead terminal (102b) welded to the positive electrode current collector (101a) and the negative electrode current collector (102a) are configured to directly exit from between the two laminated films as external terminals. .
[0009]
[Problems to be solved by the invention]
In the above-described film-type battery, generally, terminals are provided so as to protrude to the outside from between two exterior films. In order to seal a portion where the terminal is exposed, a thin metal foil is usually used for the terminal.
[0010]
However, since the thin metal foil protrudes to the outside, a load is easily applied to the base end portion protruding to the outside, and the protruding portion of the connection terminal is easily damaged. Further, since the load is likely to be applied to the base end portion, the sealing portion is loosened, which causes liquid leakage. Further, the terminal protruding outside has been an obstacle to downsizing the film-type power storage device.
[0011]
Large batteries such as electric vehicle power supplies, wind power generation, power storage for photovoltaic energy, and load conditioners require high energy density and high output characteristics. Although practically used, it was possible to increase the energy density of a film type battery, but it was difficult to obtain high output characteristics. The terminal coming out of the laminate film uses the thin metal foil as described above in consideration of sealing, and the resistance of the terminal itself greatly contributes. Therefore, a thick metal plate is considered as a terminal for large film type batteries, but it is difficult to seal it, and at the same time, when vibration is constantly applied, for example, for electric vehicles, the sealing part is easily loosened, so it is durable. Sex is required. Further, in such a terminal shape, the volume occupied by the terminal projecting to the outside becomes large, and when the terminal is actually mounted on an automobile or the like, an extra space is required, which causes a reduction in energy density.
[0012]
Under such circumstances, an object of the present invention is to provide a film-type power storage device in which exposed portions of connection terminals have high durability. Another object of the present invention is to provide a more compact film-type power storage device. Another object of the present invention is to provide a film-type power storage device which can reduce resistance of a connection portion in connection between a terminal and an external circuit.
[0013]
Further, another object of the present invention is to provide a power storage device having excellent charge / discharge characteristics. Another object of the present invention is to provide a power storage device which can be charged and discharged for a long time and has excellent safety. Still another object of the present invention is to provide a power storage device that is easy to manufacture.
[0014]
[Means for Solving the Problems]
In order to solve the above problems, the present inventors have conducted intensive research and obtained an idea of dividing a connection terminal exposed to the outside and further an idea of arranging a connection terminal on a surface of a sealing portion of an exterior film. Thus, the present invention has been completed. That is, the present invention is as follows.
[0015]
[1] A power storage device including: a power storage unit including at least one pair of a positive electrode and a negative electrode; an exterior film that covers and seals the power storage unit; and a connection terminal to the outside of the positive electrode and the negative electrode, wherein the exterior film The exterior films are at least partially overlapped and sealed, and the connection terminals of the positive electrode and the negative electrode are exposed to the outside from the portion where the exterior films are overlapped, and the exposed portions of the connection terminals that are exposed to the outside are exposed. Is divided into a plurality of portions, and a part of the divided exposed portion is disposed on one surface of the seal portion and the other portion is disposed on the other surface of the seal portion, respectively.
[2] The film-type power storage device according to the above [2], wherein an exposed portion of the connection terminal is vertically divided.
[3] The film-type power storage device according to the above [3], wherein the connection terminal is formed by laminating two sheets, and each sheet is vertically divided.
[4] The film-type power storage device according to [2], wherein an exposed portion of the connection terminal is divided into right and left.
[5] The positive electrode active material is a material capable of reversibly supporting lithium ions and / or anions, and the negative electrode active material is a material capable of reversibly supporting lithium ions. The capacitance has at least three times the capacitance per unit weight of the positive electrode active material, the weight of the positive electrode active material is larger than the weight of the negative electrode active material, and the lithium electrode for preliminarily supporting lithium on the negative electrode is used The film-type power storage device according to any one of the above [1] to [4], which is provided.
[6] The power storage unit includes a positive electrode current collector and a negative electrode current collector, each of the current collectors has a hole penetrating on the front and back surfaces, and the lithium electrode capable of electrochemically supplying lithium to the negative electrode. The film-type power storage device according to the above [5], wherein is opposed to the negative electrode and / or the positive electrode.
[7] The above-mentioned [5] or [6], wherein the active material of the negative electrode is an insoluble infusible substrate having a polyacene skeleton structure in which the atomic ratio of hydrogen atoms / carbon atoms is 0.50 to 0.05. The film-type power storage device according to claim 1.
[0016]
The film-type power storage device of the present invention is a power storage device covered with a film. A power storage device is a device that can store electric energy and is a device that can be discharged at least once. That is, regarding batteries, both primary batteries and secondary batteries are included, and capacitors are also included in the power storage device.
[0017]
The power storage device of the present invention includes a power storage unit including at least one pair of a positive electrode and a negative electrode, an exterior film that covers and seals the power storage unit, and a connection terminal for connecting the positive electrode and the negative electrode to the outside. The exterior film is sealed by overlapping at least a part of the exterior films, and seals the contents such as a power storage unit.
[0018]
In the following examples and examples shown in the drawings, a pair of exterior films is used, and they are overlapped so as to cover the contents, and the outer periphery is heat-sealed to seal the contents. are doing. In the examples and the like, the four sides are heat-sealed using a sheet-like film member, but in the present invention, the shape of the exterior film is not particularly limited, and in addition to the sheet-like film member shown in the examples and the like, a cylindrical shape Alternatively, a film member that has been formed in advance into a bag shape may be used. When using a cylindrical molded film member, the contents are hermetically sealed by heat-sealing two opposing sides. When a bag-like film member is used, the contents are hermetically sealed by heat sealing one open side.
[0019]
The connection terminals of the positive electrode and the negative electrode serving as connection ports to the outside are exposed to the outside from the space where the outer films are overlapped to form an exposed portion. The exposed portion of the connection terminal that is exposed to the outside is divided into a plurality, and a part of the divided exposed portion is disposed on one surface of the seal portion, and the other portion is disposed on the other surface of the seal portion.
[0020]
The form of division is not particularly limited as long as a part of the exposed part can be arranged on one surface of the seal part and the other part can be arranged on the other surface. As one example, an exposed portion of the connection terminal is formed in a sheet shape, and the sheet-shaped exposed portion is divided into upper and lower portions. Splitting up and down means splitting in the direction perpendicular to the plane of the sheet. The upper and lower divisions can be easily realized by, for example, laminating two sheets to form connection terminals, and dividing each sheet at an exposed portion outside the exterior film. Further, as still another example, the sheet-shaped exposed portion may be divided into right and left. The division into right and left means division into horizontal directions with respect to the plane of the sheet. More specifically, the exposed portion may be divided into two by making a cut from the end of the exposed portion toward the power storage unit main body. Note that the exposed portion may be divided into a plurality of portions, that is, at least two or more.
[0021]
In a film-type power storage device, since connection terminals are exposed to the outside from between exterior films, there is a strong tendency to make connection terminals as thin as possible from the viewpoint of maintaining airtightness. For this reason, it is required to suppress the resistance of the peripheral portion related to the connection including the connection terminal and the like. As described above, a form in which two sheets are overlapped to form a connection terminal, and each sheet is divided at an exposed portion, is a simple means, and ensures a sufficient exposed area of the connection terminal, It is suitable for suppressing the resistance at the portion related to the connection terminal. On the other hand, as described above, the form of dividing horizontally can be achieved with one sheet, so that the thickness can be suppressed, and the airtightness of the seal portion from which the connection terminal goes out can be easily secured. Is preferred.
[0022]
The divided exposed part is arranged on the surface of the seal part. In order to dispose it on the surface, the exposed portion protruding outward from the exterior film may be turned over toward the power storage device main body side and folded back to the surface of the exterior film. A part of the divided exposed portion is disposed on one surface of the seal portion, and the other portion is disposed on the other surface of the seal portion. Therefore, there are exposed portions of the connection terminals on both the front surface and the rear surface of the seal portion. Since the length of the exposed portion is not particularly limited, the end of the exposed portion may exceed the seal portion. Since the connection terminals are provided along the sealing portion of the exterior film, the mechanical durability is higher than in a state where the connection terminals are projected. The durability is further improved by fixing the seal portion and the terminal with a double-sided tape or the like. In the case of the connection terminal that has been protruded, a load is likely to be applied to the base end portion coming out of the exterior film, and the connection terminal was sometimes damaged. However, the configuration in which both surfaces of the front and back surfaces of the seal portion are sandwiched between the exposed portions of the connection terminals as in the present invention, since the load is evenly applied to both surfaces of the seal portion, the load on the base portion can be significantly reduced. Can be. On the other hand, even when the connection terminal has one exposed portion and is folded back and fixed to only one surface of the seal portion, the load on the base end portion is concentrated on the opposite side, and liquid leakage may occur due to peeling or the like, Insufficient. As a more specific example, when connecting the connection terminals of the power storage device with scissors or clip-shaped connection terminals from the outside, the connection terminals are sandwiched together with the outer film, so that the terminals are maintained in a stable connection state. In addition, the load applied to the root of the connection terminal of the power storage device is extremely small due to the weight of the connection terminal from the outside, the connection work, and the like. That is, the power storage device of the present invention is less likely to damage the connection terminal portion. In addition, since the connection terminal is disposed on the surface of the seal portion, there is substantially no protrusion, and a more compact cell can be obtained. (In this specification, the power storage unit is sealed with an exterior film. One unit may be referred to as a “cell”).
[0023]
INDUSTRIAL APPLICABILITY As described above, the present invention is suitably applied to a lithium power storage device and the like that are required to be further compact while utilizing the characteristics of high output and high energy density.
[0024]
“Positive electrode” is a pole on the side from which current flows during discharge, and “negative electrode” is a pole on the side to which current flows during discharge. The positive electrode active material and the negative electrode active material used in the power storage device of the present invention are not particularly limited, and electrode materials generally used for batteries or capacitors can be used. As a preferred embodiment of the present invention, for example, a material capable of reversibly supporting lithium ions and / or anions of the positive electrode active material, a material capable of reversibly supporting lithium ions in the negative electrode active material, and a unit weight of the negative electrode active material The capacitance per unit has a capacitance of at least three times the capacitance per unit weight of the positive electrode active material, and the weight of the positive electrode active material is larger than the weight of the negative electrode active material. In the case of employing the structure, a power storage device with high voltage and high capacity can be obtained. Note that in this specification, an embodiment of the present invention having such a configuration may be referred to as a first embodiment of a lithium-ion power storage device.
[0025]
Generally, a capacitor uses substantially the same amount of the same active material (mainly activated carbon) for a positive electrode and a negative electrode. The active material used for the positive electrode and the negative electrode has a potential of about 3 V at the time of cell assembly. By charging, the anion forms an electric double layer on the positive electrode surface and the positive electrode potential rises, while the positive electrode potential rises. The cations form an electric double layer and the potential drops. Conversely, at the time of discharging, anions are released from the positive electrode and cations are released from the negative electrode into the electrolytic solution, and the potentials respectively fall and rise, and return to around 3V. In other words, the shape of the charge / discharge curve of the positive electrode and the negative electrode is substantially line-symmetrical with 3 V as a boundary, and the amount of potential change of the positive electrode and the amount of potential change of the negative electrode are substantially the same. The positive electrode has almost only anions and the negative electrode has almost only cations.
[0026]
On the other hand, in the lithium secondary battery according to the first embodiment, an active material capable of reversibly supporting lithium ions and / or anions is used for a positive electrode, which is a conventional positive electrode of an electric double layer capacitor. Activated carbon used for the negative electrode may be used. An aprotic organic solvent solution of a lithium salt is used for the electrolyte part, and the negative electrode has a capacitance of three times or more the capacitance per unit weight of the positive electrode active material, and the weight of the positive electrode active material is A lithium electrode, which is larger than the active material weight and allows lithium to be preliminarily supported on the negative electrode, is provided in the power storage unit. For example, the lithium electrode is designed so that lithium can be preliminarily supported on the negative electrode before charging. The power storage device of the present invention achieves high capacity by the following three mechanisms.
[0027]
First of all, by using a negative electrode having a large capacitance per unit weight with respect to the capacitance per unit weight of the positive electrode, the weight of the negative electrode active material is reduced without changing the potential change amount of the negative electrode. This makes it possible to increase the filling amount of the positive electrode active material and increase the capacitance and capacity of the cell. In another design, since the capacitance of the negative electrode is large, the amount of change in the potential of the negative electrode is small. As a result, the amount of change in the potential of the positive electrode is large, and the capacitance and capacity of the cell are large.
[0028]
Second, by pre-loading a predetermined amount of lithium on the negative electrode in advance to obtain the required capacity as the negative electrode capacity, the negative electrode potential is lower than 3 V while the positive electrode potential during cell assembly is about 3 V. It is becoming.
[0029]
In this embodiment, "the lithium is pre-loaded on the negative electrode before charging" means that the lithium has already been loaded on the negative electrode before charging the power storage device. Does not carry lithium supplied from the electrolyte part. A method of preliminarily supporting lithium on the negative electrode will be described later.
[0030]
The voltage when the voltage of the cell is increased until the electrolyte is oxidatively decomposed is substantially determined by the positive electrode potential. Compared with a power storage device having a normal cell configuration, the power storage device of the present invention having a structure in which lithium is preliminarily loaded has a higher withstand voltage, because the negative electrode potential is lower. In other words, while the operating voltage of a normal capacitor is about 2.3 to 2.7 V, according to the above-described embodiment, it can be set as high as 3 V or more, and the energy density is improved.
[0031]
Third, there is an increase in the capacity of the positive electrode due to the low negative electrode potential. When the negative electrode potential is low, it is possible to further increase the amount of change in the potential in discharging the positive electrode. Depending on the design, the potential of the positive electrode falls below 3 V at the end of discharge, and it is possible to lower the discharge potential to, for example, 2 V (this is mainly due to emission of anions up to 3 V discharge and doping of lithium ions below 3 V). Potential has dropped).
[0032]
In the conventional electric double layer capacitor, the potential of the positive electrode drops only to about 3 V at the time of discharging, because the negative electrode potential also becomes 3 V and the cell voltage becomes 0 V at that time. That is, the configuration of the embodiment in which the positive electrode potential can be reduced to 2 V has a higher capacity than the configuration of the conventional electric double layer capacitor that can reduce only to 3 V.
[0033]
Here, in this specification, the capacitance and the capacitance are defined as follows. The capacitance of a cell indicates the amount of electricity (gradient of a discharge curve) flowing through the cell per unit voltage of the cell, and the unit is F (farad). The capacitance per unit weight of the cell is relative to the capacitance of the cell. It is indicated by dividing the total weight of the positive electrode active material weight and the negative electrode active material weight filled in the cell (unit: F / g). The capacitance of the positive electrode or the negative electrode indicates the amount of electricity (gradient of the discharge curve) flowing through the cell per unit voltage of the positive electrode or the negative electrode, and the unit is F. The capacitance per unit weight of the positive electrode or the negative electrode is It is a value obtained by dividing the capacitance of the positive electrode or the negative electrode by the weight of the positive electrode or the negative electrode active material filling the cell, and the unit is F / g.
[0034]
Further, the cell capacity is the difference between the discharge start voltage and the discharge end voltage of the cell, that is, the product of the amount of voltage change and the capacitance of the cell, and the unit is C (coulomb). Is the amount of charge at the time of flowing, and in this patent, it is determined to be converted to mAh. The positive electrode capacity is the product of the difference between the positive electrode potential at the start of discharge and the positive electrode potential at the end of discharge (positive electrode potential change amount) and the positive electrode capacitance. The unit is C or mAh. Is the product of the difference between the negative electrode potential and the negative electrode potential at the end of discharge (amount of change in the negative electrode potential) and the capacitance of the negative electrode. The unit is C or mAh. The cell capacity, the positive electrode capacity, and the negative electrode capacity match.
[0035]
In the lithium ion power storage device according to the present invention, the means for preliminarily supporting lithium on the negative electrode is not particularly limited.For example, separately from the present lithium ion power storage device, a power storage element that can supply lithium such as metal lithium is used as a lithium electrode. A method in which a predetermined amount of lithium is supported on the negative electrode and then incorporated into the present lithium-ion power storage device. At this time, the negative electrode and the lithium electrode may be in physical contact (short circuit) or may be electrochemically supported. As another means, an industrially simpler method is a method in which lithium is supported on a negative electrode from metallic lithium disposed in a cell. At this time, the negative electrode and the lithium electrode may be in physical contact (short circuit) or may be electrochemically supported.
[0036]
In general, in order to obtain high output characteristics, a power storage device generally winds a positive electrode and a negative electrode with a separator interposed therebetween or has a multilayer structure. A multi-layered power storage device includes a positive electrode current collector and a negative electrode current collector that collect and send electricity to a positive electrode and a negative electrode, respectively. In the present invention, the positive electrode current collector and the negative electrode current collector are not particularly limited, but when the positive electrode and the negative electrode have a multilayer structure, and in the case of a power storage provided with a lithium electrode, the power storage is the positive electrode current collector and the negative electrode A current collector is provided, each current collector has a hole penetrating on the front and back surfaces, and the lithium electrode is provided at a position facing the negative electrode so that lithium can be electrochemically supplied to the negative electrode. Is preferable (referred to as a second embodiment). In this case, for the positive electrode current collector and the negative electrode current collector, for example, a material having a hole penetrating the front and back surfaces such as expanded metal is used, lithium is disposed to face the negative electrode or the positive electrode, and the electrode is wound or Arranging it on a part of the power storage body such as the outermost periphery is the most convenient for industrial production, and it is preferable because lithium can be supported on the negative electrode more smoothly. Lithium may be attached to the entire surface of the negative electrode. However, when the electrode is made thin in order to obtain high output characteristics, the lithium to be attached becomes thin, and handling tends to be difficult in industrial production.
[0037]
In a preferred embodiment of the present invention, as described above, those each having a hole penetrating the front and back surfaces are preferable, and examples thereof include expanded metal, punching metal, a net, and a foam. . The form, number, and the like of the through holes are not particularly limited, and can be appropriately set so that lithium ions in the electrolyte described below can move between the front and back of the electrode without being interrupted by the electrode current collector. .
[0038]
The porosity of this electrode current collector is defined as a value obtained by converting the ratio of {1- (current collector weight / true specific gravity of current collector) / (current collector apparent volume)} into a percentage. When the porosity is high, it is desirable that lithium is supported on the negative electrode for a short time and unevenness is not easily generated. However, it is difficult to hold the active material in the opening, and the strength of the electrode is weak. Will decrease. Furthermore, the active material at the opening, particularly at the edge, tends to fall off, which may cause an internal short circuit in the battery.
[0039]
On the other hand, when the porosity is low, although it takes time until lithium is carried on the negative electrode, the electrode strength is high and the active material is hardly dropped off, so that the electrode yield is high. It is desirable that the porosity and the pore diameter of the current collector be appropriately selected in consideration of the battery structure (laminated type, wound type, etc.) and productivity.
[0040]
In addition, as the material of the electrode current collector, various materials generally proposed for lithium-based batteries can be used, such as aluminum and stainless steel for the positive electrode current collector, and stainless steel and copper for the negative electrode current collector. Nickel or the like can be used respectively.
In the power storage device according to the first embodiment of the present invention or the like, lithium in the case of being supported by electrochemical contact with lithium disposed in a cell means at least lithium such as lithium metal or lithium-aluminum alloy. A substance that contains and can supply lithium ions.
[0041]
In another preferred embodiment of the present invention, the capacitor has a cell configuration in which three or more layers are laminated by winding a positive electrode and a negative electrode, or by laminating a plate-like positive electrode and a negative electrode. Power storage device including a simple power storage body. Since such a power storage unit has a cell configuration with a large electrode area per cell unit volume, a high-voltage capacitor with a large output can be obtained unlike a coin-type battery.
[0042]
The positive electrode active material used in the present invention is not particularly limited as long as it can reversibly support lithium ions and anions such as, for example, tetrafluoroborate. Preferred materials include, for example, activated carbon and highly conductive materials. Molecules, polyacene-based substances, and the like. Among them, the use of an insoluble and infusible substrate (hereinafter, referred to as “PAS”) having a polyacene skeleton structure in which the atomic ratio of hydrogen atoms / carbon atoms is 0.50 to 0.05 has a high capacity. Is more preferred in that As will be described in detail below, PAS is obtained by, for example, heat-treating an aromatic condensation polymer.
[0043]
The negative electrode active material in the present invention is not particularly limited as long as it can support lithium reversibly. Examples of preferable materials include various carbon materials such as graphite, hard carbon, and coke, polyacene-based materials, and tin oxide. And silicon oxide. Among them, the use of the above-mentioned PAS is more preferable in that a high capacity can be obtained. The present inventors obtain a capacitance of 650 F / g or more when discharging after carrying (charging) 400 mAh / g of lithium in the PAS, and 750 F / g when charging lithium of 500 mAh / g or more. It has been found that the above capacitance can be obtained.
[0044]
Since the capacitance per unit weight of the positive electrode and the negative electrode of a general electric double layer capacitor is about 60 to 200 F / g, it is understood that the PAS has a very large capacitance. In consideration of the capacitance of the positive electrode used, by appropriately controlling the amount of lithium charged to the negative electrode, a capacitance of at least three times the capacitance per unit weight of the positive electrode is ensured, and the weight of the positive electrode active material is reduced. The most advantageous effect is obtained when the combination is larger than the weight of the negative electrode active material.
[0045]
Even if the capacitance per unit weight of the negative electrode is three times or more the capacitance per unit weight of the positive electrode, if the weight of the positive electrode active material is smaller than the weight of the negative electrode active material, the conventional electric double layer The increase in capacitance is smaller than that of the capacitor.
[0046]
In a preferred embodiment of the present invention, an active material having a so-called amorphous structure in which the potential gradually decreases with the insertion of lithium, such as PAS, and the potential increases with the elimination of lithium, is used for the negative electrode. In this case, since the potential decreases as the amount of lithium carried increases, the withstand voltage (charging voltage) of the obtained power storage device increases, and the rate of rise of the voltage during discharge (gradient of the discharge curve) decreases. The capacity is slightly larger. Therefore, it is desirable that the amount of lithium be appropriately set within the range of the lithium storage capacity of the active material according to the required operating voltage of the power storage device.
[0047]
In addition, since PAS has an amorphous structure, there is no structural change such as swelling and shrinkage with respect to insertion and desorption of lithium ions, so that it has excellent cycle characteristics, and isotropic with respect to insertion and desorption of lithium ions. Since it has a molecular structure (higher-order structure), it has excellent characteristics in rapid charging and rapid discharging, and thus is suitable as a negative electrode material.
[0048]
The aromatic condensation polymer that is a precursor of PAS is a condensate of an aromatic hydrocarbon compound and an aldehyde. As the aromatic hydrocarbon compound, so-called phenols such as phenol, cresol, xylenol and the like can be suitably used. For example,
[0049]
Embedded image

(Where x and y are each independently 0, 1 or 2)
Methylene bisphenols, or hydroxy biphenyls or hydroxynaphthalenes. Of these, phenols, particularly phenol, are practically preferred.
[0050]
Further, as the aromatic condensation polymer, a part of the aromatic hydrocarbon compound having a phenolic hydroxyl group is replaced with an aromatic hydrocarbon compound having no phenolic hydroxyl group, for example, xylene, toluene, aniline, or the like. A modified aromatic condensation polymer, for example, a condensate of phenol, xylene and formaldehyde can also be used. Further, a modified aromatic polymer substituted with melamine or urea can be used, and a furan resin is also suitable.
[0051]
As the aldehyde, aldehydes such as formaldehyde, acetaldehyde, and furfural can be used, and among these, formaldehyde is preferable. The phenol formaldehyde condensate may be any of a novolak type, a resol type and a mixture thereof.
[0052]
The insoluble infusible substrate is obtained by heat-treating the aromatic polymer, and has a polyacene-based skeleton structure described in JP-B 1-44421, JP-B 3-24024 and the like. All the insoluble and infusible substrates can be used.
[0053]
The insoluble and infusible substrate used in the present invention can be produced, for example, as follows. That is, the aromatic condensation polymer is gradually heated to an appropriate temperature of 400 to 800 ° C. in a non-oxidizing atmosphere (including vacuum) to obtain an atomic ratio of hydrogen atoms / carbon atoms (hereinafter H / C) of 0.5 to 0.05, preferably 0.35 to 0.10.
[0054]
In addition, a method described in Japanese Patent Publication No. ² / G or more can be obtained. For example, a solution containing an initial condensation product of an aromatic condensation polymer and an inorganic salt such as zinc chloride is prepared, and the solution is heated and cured in a mold.
[0055]
The cured product thus obtained is gradually heated to a temperature of 350 to 800 ° C., preferably 400 to 750 ° C. in a non-oxidizing atmosphere (including vacuum), and then water or By sufficiently washing with dilute hydrochloric acid or the like, the above H / C is obtained, and for example, 600 m ² / G or more can be obtained.
[0056]
According to the X-ray diffraction (CuKα), the insoluble infusible substrate used in the present invention has a main peak at a position of 24 ° or less expressed by 2θ and 41 to 46 ° in addition to the main peak. There are other broad peaks in between. That is, it is suggested that the insoluble and infusible substrate has a polyacene-based skeleton structure in which an aromatic polycyclic structure is appropriately developed and has an amorphous structure, and can be doped stably with lithium. It is useful as an active material for a power storage device.
[0057]
The positive electrode or negative electrode in the present invention is preferably formed by molding a positive electrode or negative electrode active material having a shape such as powder, granule, or short fiber, which is easily formed, with a binder. As the binder, for example, a rubber-based binder such as SBR, a polytetrafluoroethylene, a fluorinated resin such as polyvinylidene fluoride, a polypropylene, and a thermoplastic resin such as polyethylene can be used. Among these, a fluorine-based binder is used. Is preferred. In particular, it is preferable to use a fluorine-based binder having an atomic ratio of fluorine atoms / carbon atoms (hereinafter, referred to as F / C) of less than 1.5 and 0.75 or more, and a fluorine-based binder of less than 1.3 and 0.75 or more. More preferably, a binder is used.
[0058]
Examples of the above-mentioned fluorine-based binder include polyvinylidene fluoride, vinylidene fluoride-co-fluorinated ethylene copolymer, ethylene-co-fluoro ethylene copolymer, and propylene-co-fluoro ethylene copolymer. A fluorinated polymer in which hydrogen in the chain is substituted with an alkyl group can also be used.
[0059]
In the case of the above-mentioned polyvinylidene fluoride, F / C is 1, and in the case of the vinylidene fluoride-3fluoroethylene copolymer, when the molar fraction of vinylidene fluoride is 50% and 80%, F / C is F / C, respectively. C becomes 1.25 and 1.1. Further, in the case of a propylene-tetrafluoroethylene copolymer, when the molar fraction of propylene is 50%, the F / C is 0.75. Among these, polyvinylidene fluoride and a vinylidene fluoride-3fluoroethylene copolymer having a molar fraction of vinylidene fluoride of 50% or more are preferable, and practically, polyvinylidene fluoride is preferably used.
[0060]
In addition, a conductive material such as acetylene black, graphite, or metal powder may be appropriately added to the positive electrode or negative electrode active material as needed. The mixing ratio of the conductive material varies depending on the electric conductivity of the active material, the shape of the electrode, and the like, but is preferably added at a ratio of 2 to 40% with respect to the active material.
[0061]
In the power storage device of the present invention, the electrolyte section is formed of an electrolyte and a medium in which the electrolyte can be dissolved, and more specifically, is formed as an electrolyte in which the electrolyte is dissolved in a solvent. For example, an aprotic organic solvent is preferably used as a solvent constituting the electrolytic solution. Examples of the aprotic organic solvent include ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, γ-butyrolactone, acetonitrile, dimethoxyethane, tetrahydrofuran, dioxolan, methylene chloride, sulfolane, and the like. Furthermore, a mixed solution obtained by mixing two or more of these aprotic organic solvents can also be used.
[0062]
As the electrolyte to be dissolved in the single or mixed solvent, any electrolyte can be used as long as it can generate lithium ions. Such electrolytes include, for example, LiI, LiClO ₄ , LiAsF ₆ , LiBF ₄ , LiPF ₆ And the like.
[0063]
The electrolyte and the solvent are mixed in a sufficiently dehydrated state to form an electrolyte. The concentration of the electrolyte in the electrolyte is at least 0.1 mol / l in order to reduce the internal resistance due to the electrolyte. More preferably, it is more preferably in the range of 0.5 to 1.5 mol / l.
[0064]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings. FIGS. 1 to 6 each show a power storage device in which contents such as a power storage unit are covered and sealed with exterior films (4) and (5), in which connection terminals are provided at left and right ends of the power storage device, respectively. It is. 1 is a perspective view of a film-type power storage device, FIG. 2 is a front view, FIG. 3 is a left side view, and FIG. 4 is a plan view. FIG. 5 is a view showing a cross section along the line II ′ shown in FIG. 4, and FIG. 6 is a bottom view of the exterior film (4) seen through. In FIG. 6, the illustration of the positive electrode terminal (1b) and the negative electrode terminal (2b) on the surface of the exterior film (4) is omitted.
[0065]
In the example shown in FIGS. 1 to 6, the outer films (4) and (5) are heat-sealed on the four sides of the peripheral edge, respectively, to form a seal portion (C in FIG. 6). The positive electrode terminal (1b) is disposed at the left end of the seal, and the negative electrode terminal (2b) is disposed at the right end of the seal. As shown in FIGS. 2 to 4, the positive electrode terminal (1 b) and the negative electrode terminal (2 b) whose exposed portions to the outside are formed in a sheet shape are arranged on the upper surface and the lower surface of the seal portion, respectively. Therefore, the connection terminal does not protrude as in the related art, and the power storage device is compact because the protrusion of the terminal is eliminated. Further, the exposed portion is located on the surface of the exterior film, and is in a state of sandwiching the sealing portion of the exterior film from above and below. Therefore, in the case where the exposed portions of the positive electrode terminal (1b) and the negative electrode terminal (2b) are connected by scissor-type terminals from the outside, the connection is more stable than when connecting only thin terminals as in the related art. It can be connected in the state. In addition, since a portion that appears between the outer films of the connection terminals as in the related art, that is, an excessive load is not applied to the base end of the connection terminal, the connection terminal is hardly damaged and the durability of the connection terminal is high. .
[0066]
FIG. 5 is a sectional view taken along the line II shown in FIG. The configuration of the connection terminal will be further described using the positive terminal (1b) as an example. The positive electrode terminal (1b) in this example is configured by stacking two metal foils. Although the positive electrode terminal (1b) is fused to the inner surface of the exterior film (4), it may be fused through a sealant film, for example. The positive electrode terminal (1b) extends from the inside of the cell to the outside of the cell from between the exterior film (4) and the exterior film (5) to form an exposed portion. The exposed portions of the upper and lower two sheets constituting the positive electrode terminal (1b) are folded back, and the upper sheet is on the surface of the outer film (4), and the lower sheet is on the surface of the outer film (5). It is arranged and fixed. The two positive electrode terminals (1b) are both welded to the terminal welds of the positive electrode current collector inside the cell, and the two positive electrode terminals (1b) are heat-sealed between the positive electrode terminal and the exterior film (A). A sealant film is also interposed between the terminals to bond the terminals to each other at the time of heat fusion (not shown). However, if the two positive electrode terminals (1b) are tightly adhered to each other by, for example, ultrasonic welding inside the cell, the above-mentioned sealant film may not be used. A terminal having high durability and capable of stable connection is formed by a simple method as a measure of dividing and folding each sheet constituting the positive electrode terminal (1b) into two.
[0067]
Subsequently, another configuration of the example shown in FIGS. 1 to 6 will be described. In this example, the exterior film (5) is embossed for the thickness of the power storage unit composed of the positive electrode (1), the negative electrode (2), the separator (3), and the like. Either or both of 5) may be embossed.
[0068]
As shown in FIG. 5, the positive electrode (1) formed on both sides of the positive electrode current collector (1a) and the negative electrode (2) formed on both sides of the negative electrode current collector (2a) are connected to a separator (3). It is laminated through. The separator (3) is made of a porous material having continuous air holes that are durable with respect to an electrolytic solution or an electrode active material and the like, and is usually made of glass fiber, polyethylene, polypropylene, or the like. Alternatively, a porous body is used. The thickness of the separator (3) is preferably thinner in order to reduce the internal resistance of the capacitor, but can be appropriately set in consideration of the amount of retained electrolyte, flowability, strength, and the like.
[0069]
The separator (3) is impregnated with an electrolytic solution. In the electrolytic solution, a compound described below capable of generating ions capable of being carried on the positive electrode and the negative electrode is dissolved in an aprotic organic solvent. The electrolyte is usually in a liquid state and impregnated in the separator (3). However, in order to prevent leakage, a gel or solid electrolyte is used, and the separator (3) may not be used.
[0070]
Each of the positive electrode current collector (1a) and the negative electrode current collector (2a) may have a hole (not shown) penetrating the front and back surfaces, and each has a positive electrode terminal (1b) and a negative electrode terminal of a cell. (2b) is connected.
[0071]
Hereinafter, still another example will be described sequentially, but the description will focus on the characteristic portions, and the description of the same configuration will be omitted.
[0072]
FIG. 7 shows another example of the present invention, and FIG. 7 shows only main parts. In the example shown in FIG. 7, the positive terminal (1b) and the negative terminal (2b) are provided on the same side. By providing the positive electrode terminal (1b) and the negative electrode terminal (2b) on the same side, a space for connecting the current collector and the connection terminal inside the cell only needs to be provided on one side only. It is possible to increase the volume of the configured power storage unit.
[0073]
8 to 11 show still another example of the present invention. In this example, the negative terminal (2b) will be described as an example. 8 is a perspective view showing the negative electrode terminal side, FIG. 9 is a right side view of the negative electrode terminal side, and FIG. 10 is a cross-sectional view of the negative electrode terminal portion. 8 to 9 show only the main parts. FIG. 11 is a perspective view of the negative electrode terminal (2b).
[0074]
In the above two examples, the connection terminals are formed by stacking two sheets. In the examples shown in FIGS. 8 to 11, one sheet is divided into two right and left sides. As shown in FIG. 11, the negative electrode terminal (2b) has a cut in the longitudinal direction on the right side and is divided into left and right, that is, horizontally. The cuts are made by the length corresponding to the exposed part. One of the divided portions is turned upside down and bent, and the other split portion is turned down and bent. As shown in FIGS. 10 and 11, the portion turned upside down and bent is fixed on the surface of the exterior film (4) by, for example, a double-sided tape, and the portion turned upside down and bent is placed on the exterior film. It is fixed on the surface of (5) by, for example, a double-sided tape.
[0075]
The example shown in FIGS. 8 to 11 is a simple process in which the exposed portion of the connection terminal is divided into a plurality of portions in the horizontal direction and bent, thereby improving the durability of the connection terminal, stabilizing the connection with the external terminal, and the like. The effect is obtained.
[0076]
FIGS. 12 to 14 and FIGS. 15 to 17 show, as another embodiment of the present invention, examples of the arrangement of electrodes of a capacitor having a winding type structure used for a rectangular battery or the like. FIG. 13 is a sectional view taken along the line IV-IV ′ of FIG. 12, and FIG. 14 is a sectional view taken along the line II ′ of FIG. FIG. 16 is a sectional view taken along the line II ′ of FIG. 15, and FIG. 17 is a sectional view taken along the line IV-IV ′ of FIG.
[0077]
The electrode winding units used in the two examples shown in FIGS. 12 to 17 are formed by pressing a ribbon-shaped positive electrode and a negative electrode in an elliptical shape via a separator and then press-forming. In these electrode arrangements, the positive electrode (1) and the negative electrode (2) are each formed on a current collector.
[0078]
The example shown in FIGS. 12 to 15 is a case in which a sheet-like positive electrode, a negative electrode, and an electrode winding unit having a winding-type structure obtained by stacking and winding each current collector are formed, This is an example in which a plate-shaped lithium metal (7) is provided at the center of the electrode winding unit. Note that a laminated portion formed by winding each sheet is referred to as a laminated portion of the electrode winding unit. A lithium current collector (7a) is provided between two lithium metals (7) (FIG. 13). As shown in FIGS. 12 to 15, the negative electrode current collector (2 a) has, on the negative electrode terminal side of the outermost peripheral portion of each sheet, a lead portion for connecting to the negative electrode terminal, from the laminated portion of the electrode winding unit. In FIG. 14, the current collectors are shown and the positive electrode, the negative electrode, and the like are omitted in the laminated portion of the electrode winding unit for the sake of overview.
[0079]
In addition, the lithium electrode current collector (7a) is also provided with a lead portion for connecting to the negative electrode terminal in a form protruding from the laminated portion. In addition, a lead portion is formed so that the positive electrode current collector (1a) also protrudes from the layered portion of the electrode winding unit (9) to the positive terminal side. It is connected.
[0080]
In the examples shown in FIGS. 15 to 17, the lithium metal (7) is attached to the outer periphery of the separator (3) which is the outermost periphery of the wound body (FIG. 16). As shown in FIG. 15, the lithium current collector (7 a) and the negative electrode current collector (2 a) are overlapped and wound with other layer members so that the respective sheet-like members protrude toward the negative electrode terminal. A lead portion protruding from the laminated portion of the electrode winding unit is formed, and the lithium electrode current collector (7a) and the negative electrode current collector (2a) are respectively connected on the upper surface of the negative electrode terminal. The positive electrode current collector (1a) also has a lead portion protruding from the laminated portion of the electrode winding unit to the positive terminal side, and this lead portion is guided to the upper surface of the positive terminal and connected to the positive terminal. I have.
[0081]
In the examples shown in FIGS. 12 to 17, respectively, the negative electrode and lithium are brought into contact with each other through a conductive material such as nickel, copper, and stainless steel, or by attaching lithium on the negative electrode current collector. The organic electrolyte capacitors according to the above [5] and [6] of the present invention are not particularly limited to this structure, and may be brought into contact by, for example, directly attaching lithium on the negative electrode. That is, it is only necessary that all the negative electrodes and lithium are brought into electrochemical contact with each other when the electrolytic solution is injected during cell assembly, and lithium is supported on the negative electrode active material via the electrolytic solution.
[0082]
By using a conductive porous body such as a stainless steel mesh as a lithium metal current collector and filling and arranging the pores of the conductive porous body with 80% or more of lithium metal, even if lithium is carried, The gap generated between the electrodes due to disappearance is reduced, and lithium is smoothly supported on the negative electrode active material.
[0083]
On the other hand, it is possible to dispose lithium metal in the cross-sectional direction of the negative electrode plate and electrochemically contact the negative electrode and the lithium metal in the cell to support lithium on the negative electrode active material. If the length is long, dope unevenness in the electrode becomes large. Therefore, it is desirable to select the position of lithium to be arranged in consideration of the cell configuration, the electrode size, and the like.
[0084]
In the organic electrolyte capacitor having a lithium electrode according to an embodiment of the present invention, the degree of freedom in cell design and the improvement in mass productivity can be improved by locally disposing lithium to be supported on the negative electrode at a specific position. In addition, it has excellent charge / discharge characteristics.
[0085]
In this organic electrolyte capacitor, the amount of lithium carried on the negative electrode can be determined each time depending on the negative electrode material used and the characteristics required for the organic electrolyte capacitor.
[0086]
18 and 19 are exploded perspective views showing the shape of the terminal welding portion of the electrode current collector for lamination and the lamination direction. In the example of FIG. 18, the direction is a lamination direction in which the positive terminal and the negative terminal are in opposite directions, and in the example of FIG. 19, the lamination direction is the same direction. However, the directions of the positive and negative terminals are not limited to these two types.
[0087]
20 to 22 show another embodiment of an organic electrolyte capacitor having a lithium electrode, in which lithium is arranged in a cell and a plurality of sets of a positive electrode plate, a separator, and a negative electrode plate are sequentially laminated. Each form is shown.
[0088]
FIG. 20 shows an example of electrode arrangement in a cell of a capacitor of the above type. As shown in this figure, a negative electrode (2) molded on both sides of a negative electrode current collector (2a) and a lithium metal (7) pressed against a lithium metal current collector (7a) such as a stainless steel mesh or copper expanded metal. ) Are connected by a conducting wire (8a), and the lithium metal (7) is arranged below the laminated unit.
[0089]
The negative electrode current collector (2a) and the lithium metal current collector (7a) can be directly welded. Further, the positive electrode (1) formed on both surfaces of the positive electrode current collector (1a) and the negative electrode (2) are laminated via a separator (3).
[0090]
The negative electrode current collector (2a) and the positive electrode current collector (1a) each have a hole (not shown) penetrating the front and back surfaces, and are respectively connected to the negative electrode terminal and the positive electrode terminal of the cell. .
[0091]
FIG. 21 shows another example of the electrode arrangement in the cell of the capacitor. In this capacitor, a lithium metal (7) crimped on a lithium metal current collector (7a) is arranged on the upper and lower parts of the laminated unit, respectively.
[0092]
In another example shown in FIG. 22, the lithium metal (7) is arranged in the middle of the laminated unit. As illustrated in FIGS. 20 to 22, in the stacked electrode arrangement, the arrangement position of the lithium metal (7) can be appropriately changed as in the above example.
[0093]
【Example】
Examples 1 to 3, Comparative Example 1
(Production method of negative electrode)
A phenolic resin molded plate having a thickness of 0.5 mm is placed in a siliconite electric furnace, and heated to 500 ° C under a nitrogen atmosphere at a rate of 50 ° C / hour, and further heated to 650 ° C at a rate of 10 ° C / hour and heat-treated. And PAS were synthesized. The PAS plate thus obtained was pulverized with a disk mill to obtain a PAS powder. The H / C ratio of this PAS powder was 0.22.
[0094]
Next, a slurry was obtained by sufficiently mixing 100 parts by weight of the PAS powder and a solution of 10 parts by weight of polyvinylidene fluoride powder in 120 parts by weight of N-methylpyrrolidone. The slurry was applied to both surfaces of a copper expanded metal having a thickness of 40 μm (porosity: 50%), dried, and pressed to obtain a 200 μm PAS negative electrode.
[0095]
(Production method of positive electrode)
A phenolic resin molded plate having a thickness of 0.5 mm is placed in a siliconite electric furnace, and heated to 500 ° C under a nitrogen atmosphere at a rate of 50 ° C / hour, and further heated to 650 ° C at a rate of 10 ° C / hour and heat-treated. And PAS were synthesized. The PAS was activated by steam and then pulverized by a nylon ball mill to obtain a PAS powder. The specific surface area of the powder by the BET method is 1500 m. ² / G, and H / C was 0.10 by elemental analysis.
[0096]
A slurry was obtained by sufficiently mixing 100 parts by weight of the PAS powder and 10 parts by weight of polyvinylidene fluoride powder in 100 parts by weight of N-methylpyrrolidone. The slurry was applied to both sides of a 40 μm (50% porosity) aluminum expanded metal coated with a carbon-based conductive paint, dried, and pressed to obtain a 380 μm PAS positive electrode.
[0097]
(Capacitance measurement per unit weight of negative electrode)
1.5 × 2.0 cm of the negative electrode ² Four pieces were cut out to a size to obtain a negative electrode for evaluation. 1.5 × 2.0cm as negative electrode and counter electrode ² A simulated cell was assembled with lithium metal having a size of 200 μm and a nonwoven fabric made of polyethylene having a thickness of 50 μm as a separator. Metallic lithium was used as a reference electrode. As the electrolyte, LiPF was added to propylene carbonate at a concentration of 1 mol / l. ₆ Was used.
[0098]
Lithium corresponding to 400 mAh / g with respect to the weight of the negative electrode active material was charged at a charging current of 1 mA, and then discharged to 1.5 V at 1 mA. The capacitance per unit weight of the negative electrode was determined from the discharge time during which the potential of the negative electrode changed 0.2 V from the potential of the negative electrode one minute after the start of discharge, and was found to be 653 F / g.
[0099]
(Capacitance measurement per unit weight of positive electrode)
The above positive electrode is 1.5 × 2.0 cm ² Three sheets were cut out to a size, one was used as a positive electrode, and the other was used as a negative electrode and a reference electrode. A simulated cell of a capacitor was assembled with the positive electrode and the negative electrode interposed with a 50 μm-thick paper nonwoven fabric as a separator. As the positive electrode electrolyte, a solution obtained by dissolving triethylmethylammonium / tetrafluoroborate (TEMA / BF4) at a concentration of 1 mol / l in propylene carbonate was used.
[0100]
The battery was charged to 2.5 V at a charging current of 10 mA, and then charged at a constant voltage. After a total charging time of 1 hour, the battery was discharged to 0 V at 1 mA. When the capacitance per unit weight of the cell was determined from the discharge time between 2.0 V and 1.5 V, it was 21 F / g. Similarly, the capacitance per unit weight of the positive electrode was determined from the potential difference between the reference electrode and the positive electrode and found to be 85 F / g.
[0101]
(Preparation of electrode lamination unit 1)
A PAS negative electrode having a thickness of 200 μm and a PAS positive electrode having a thickness of 380 μm were formed as shown in FIG. 18 and each had an electrode area of 5.0 × 7.0 cm. ² As shown in FIG. 18, using a 25 μm-thick cellulose / rayon mixed nonwoven fabric as a separator, a welded portion between the positive electrode current collector and the negative electrode current collector with a connection terminal (hereinafter referred to as a “connection terminal”). Welded parts are placed on opposite sides, and the positive and negative electrodes are laminated so that the opposing surfaces become 10 layers. Separators are placed at the top and bottom, and four sides are taped and laminated. Got a unit. In addition, five positive electrodes and six negative electrodes were used, and as shown in FIG. 24, two outer negative electrodes used were obtained by removing one side of the negative electrode molded on both sides. The thickness is 120 μm. The weight of the positive electrode active material is 1.7 times the weight of the negative electrode active material. As the lithium metal, a lithium metal foil (80 μm, 5.0 × 7.0 cm ² ) Was pressed onto a stainless steel net having a thickness of 80 μm, and two sheets were arranged above and below the electrode stacking unit so as to face the negative electrode. The negative electrode (two on one side, four on both sides) and the stainless steel net pressed with lithium were welded and contacted, respectively, to obtain an electrode laminated unit 1.
[0102]
(Preparation of electrode lamination unit 2)
A PAS negative electrode having a thickness of 200 μm and a PAS positive electrode having a thickness of 380 μm were formed as shown in FIG. 19 and each had an electrode area of 5.0 × 8.0 cm. ² 19, except that the connection terminal welds of the positive electrode current collector and the negative electrode current collector are arranged on the same side as shown in FIG. An electrode stacking unit was obtained. The weight of the positive electrode active material is 1.7 times the weight of the negative electrode active material. As the lithium metal, a lithium metal foil (80 μm, 5.0 × 8.0 cm ² ) Was pressed onto a stainless steel net having a thickness of 80 μm, and two sheets were arranged above and below the electrode stacking unit 2 so as to face the negative electrode. The negative electrode (two on one side, four on both sides) and the stainless steel net pressed with lithium were welded and brought into contact with each other to obtain an electrode laminated unit 2.
[0103]
(Creation of cell 1)
A terminal welding portion (5) of the positive electrode current collector of the electrode lamination unit 1 is provided between two aluminum positive electrode terminals each having a width of 10 mm, a length of 30 mm, and a thickness of 0.1 mm, in which a sealant film is previously heat-sealed to a seal portion. ) And ultrasonic welding. Similarly, the terminal welding portion (six pieces) of the negative electrode current collector is sandwiched between two nickel negative electrode terminals each having a width of 10 mm, a length of 30 mm, and a thickness of 0.1 mm, in which a sealant film is previously heat-sealed to the sealing portion. Ultrasonic welding was carried out, and it set inside 3.5 mm of deep-drawn exterior films. LiPF to a concentration of 1 mol / l in a mixed solvent of ethylene carbonate, diethyl carbonate and propylene carbonate in a weight ratio of 3: 4: 1 as an electrolytic solution. ₆ After impregnating with a solution in which is dissolved in vacuum, cover with an exterior laminate film and heat-seal the four sides. As in FIG. 5, the exposed portions of the two terminals are folded up and down, respectively, and the sealing portion of the exterior film is double-sided tape. Then, 50 cells of a film type capacitor were assembled by fixing.
[0104]
(Creation of cell 2)
As shown in FIG. 7, 50 cells of a film-type capacitor were assembled using the electrode stacking unit 2 in the same manner as the cell 1 except that the positive electrode terminal and the negative electrode terminal were on the same side.
[0105]
(Creation of cell 3)
One aluminum positive electrode terminal having a width of 20 mm, a length of 30 mm, and a thickness of 0.1 mm, in which a sealant film is heat-sealed in advance to a terminal welding portion (five) of the positive electrode current collector of the electrode stacking unit 1 at a sealing portion. Was ultrasonically welded. Similarly, one nickel negative electrode terminal having a width of 20 mm, a length of 30 mm, and a thickness of 0.1 mm, which was previously heat-sealed with a sealant film at a sealing portion, was welded to the terminal welding portion (six pieces) of the negative electrode current collector by ultrasonic welding. Then, it was placed inside the exterior film that was drawn 3.5 mm deep. LiPF to a concentration of 1 mol / l in a mixed solvent of ethylene carbonate, diethyl carbonate and propylene carbonate in a weight ratio of 3: 4: 1 as an electrolytic solution. ₆ After dissolving the solution in a vacuum, the package is covered with an exterior laminate film and the four sides are heat-sealed, and the exposed portions of the terminals are divided into right and left portions as in FIGS. Was fixed with a double-sided tape to assemble 50 cells of a film-type capacitor.
[0106]
(Creation of cell 4)
A terminal welding portion (5) of the positive electrode current collector of the electrode lamination unit 1 is placed on one aluminum positive electrode terminal having a width of 10 mm, a length of 30 mm, and a thickness of 0.2 mm in which a sealant film is previously heat-sealed to a sealing portion. Sheets) and ultrasonically welded. Similarly, the terminal welding portion (six pieces) of the negative electrode current collector is placed on one nickel negative electrode terminal having a width of 10 mm, a length of 30 mm, and a thickness of 0.2 mm, in which a sealant film is previously heat-sealed to the sealing portion. Ultrasonic welding was carried out, and it set inside 3.5 mm of deep-drawn exterior films. LiPF to a concentration of 1 mol / l in a mixed solvent of ethylene carbonate, diethyl carbonate and propylene carbonate in a weight ratio of 3: 4: 1 as an electrolytic solution. ₆ Was dissolved in a vacuum, and then covered with an exterior laminate film, and four sides were thermally fused to assemble 50 cells of a film capacitor. As shown in FIG. 23, both the positive electrode terminal and the negative electrode terminal extend outward from the sealing portion of the exterior film.
[0107]
(Initial cell evaluation)
Seven days after the assembly of the cells 1 to 4, the internal resistance, short-circuit, and liquid leakage were confirmed. The liquid leakage was confirmed after 50 cycles of a thermal shock test in which each was left at -10 ° C and 60 ° C alternately for one hour. The results are shown in Table 1. However, the internal resistance showed an average value of 50 cells.
[0108]
[Table 1]

[0109]
With respect to the internal resistance, the number of short circuits, and the number of liquid leaks immediately after the assembly, no remarkable difference was observed in the cells 1 to 4. However, in the cells using the same laminated unit 1, although slightly, the cell 1 (Example 1) and the cell 3 (Example 3) resulted in lower internal resistance than the cell 4 (Comparative Example 1). This is because the cell 1 has two positive terminals and two negative terminals, and the cell 3 has a wide terminal width, so that the electrode can be easily welded to the terminal welding portion, the welding area is large, and the contact resistance is low. It is considered that the connection of the measuring device became possible from a position closer to the base end portion because of the suppression and the fact that the terminal exposed portion was fixed to the seal portion and was stable.
[0110]
(Evaluation of cell characteristics)
After leaving at room temperature for 7 days, each of the cells having no short circuit and no liquid leakage was disassembled, and the lithium metal was completely lost in all of the cells 1 to 4. It was determined that lithium for obtaining a capacitance of 650 F / g was precharged. The capacitance ratio per unit weight of the negative electrode active material and the positive electrode active material is 7.65.
[0111]
In addition, 10 cells were charged at a constant current of 1000 mA each until the cell voltage reached 3.3 V, and thereafter, a constant current-constant voltage charge of applying a constant voltage of 3.3 V was performed for 1 hour. Next, discharging was performed at a constant current of 100 mA until the cell voltage reached 1.6 V. This cycle of 3.3V-1.6V was repeated, and the result of evaluating the cell capacity and volume energy density (however, excluding the volume of the fused portion and the terminal exposed portion of the laminate film) in the third discharge was evaluated. It is shown in Table 2. However, the cell capacity and the volume energy density are averages of 10 cells.
[0112]
[Table 2]

[0113]
The capacitance per unit weight of the negative electrode active material is at least three times the capacitance per unit weight of the positive electrode active material, and the weight of the positive electrode active material is larger than the weight of the negative electrode active material. It can be seen that the organic electrolyte capacitor designed to carry has a large energy density.
[0114]
Further, even if the film battery has the same outer size, the filling rate of the active material changes depending on how the terminals are taken, and a difference appears in the capacity and energy density. It is preferable that the terminals be in the same direction as in the cell 2 because the capacity is higher.
[0115]
(Impact test)
An impact test was performed using a test tool as shown in FIG. FIG. 26 shows a state where the unit (110) of the comparative example is fixed. A positive terminal and a negative terminal are respectively sandwiched between a terminal fixing receiving plate and a terminal fixing pressing plate on a plywood (500) having a thickness of 10 mm, a length of 80 mm, and a width of 120 mm for each of cells 1 to 4 for 20 cells. The cell was fixed with terminal fasteners (501) for tightening the screws. Thereafter, a drop test was performed 50 times each in the vertical and horizontal directions from a height of 1 m, and then the internal resistance, short circuit, and liquid leakage were confirmed. The liquid leakage was confirmed after 50 cycles of a thermal shock test in which each was left at -10 ° C and 60 ° C alternately for one hour. The results are shown in Table 3. However, the internal resistance showed an average value of 20 cells.
[0116]
[Table 3]

[0117]
In Comparative Example 1 (Cell 4), the increase in internal resistance and the number of occurrences of liquid leakage were larger than those in the Example. This is presumably because the sealing portion was loosened due to the drop and the contact resistance between the electrode terminal weld and the terminal weld was increased by the impact.
[0118]
(Comparison of energy density in 4-cell parallel considering terminal)
Using the cell 1 and the cell 4, a parallel connection type assembled cell in which four cells were stacked was prototyped. The volume when calculating the volume energy density of the stacked cells is calculated by multiplying the product of the maximum width and the maximum height including the cell body, the fused part of the laminate film, and the terminal exposed part, taking into account the mounting on the equipment. The cell area was defined as the area, and the product of the value and the thickness of the four cells was defined as the volume. The cell of Example 1 (cell 1) has no terminal overhang as in Comparative Example 1, and a compact assembled cell can be made. However, the cell of Comparative Example 1 (Cell 4) is located outside the cell. It protruded, and the volume was 15% larger than that of the assembled cell of Example 1. Therefore, it was found that the volume energy density of Example 3 was higher by 15%.
[0119]
【The invention's effect】
According to the present invention, it is possible to easily obtain a film-type power storage device in which the exposed portion of the connection terminal has high durability. Further, according to the present invention, a film-type power storage device can be made more compact. Further, according to the present invention, there is provided a film-type power storage device having a large contact surface of a connection terminal and low contact portion resistance.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a first installation example of connection terminals according to the present invention.
FIG. 2 is a front view of the first installation example shown in FIG.
FIG. 3 is a left side view of the first installation example shown in FIG. 1;
FIG. 4 is a plan view of the first installation example shown in FIG.
FIG. 5 is a view showing a cross section taken along line II ′ shown in FIG. 4;
FIG. 6 is a bottom view seen through the exterior film (4).
FIG. 7 is a perspective view showing a main part of a second installation example of connection terminals according to the present invention.
FIG. 8 is a perspective view showing a main part of a third installation example of connection terminals according to the present invention.
9 is a diagram showing a main part of a left side view of the third installation example shown in FIG. 8;
FIG. 10 is a view showing a cross section of a main part of the third installation example shown in FIG. 8;
FIG. 11 is a perspective view of a connection terminal used in the third installation example shown in FIG.
FIG. 12 is a bottom view of the first example according to the present invention, in which the electrodes and the like in the cell are arranged by winding electrodes, as seen through an exterior film (4).
13 is a diagram showing a cross section taken along line II of the example shown in FIG. 21;
FIG. 14 is a view showing a cross section taken along line IV-IV of the example shown in FIG. 21;
FIG. 15 is a bottom view of a second example according to the present invention, in which electrodes and the like in a cell are arranged as wound electrodes, as seen through an exterior film (4).
FIG. 16 is a diagram showing a cross section taken along line II of the example shown in FIG. 24;
17 is a view showing a cross section taken along line IV-IV of the example shown in FIG. 24;
FIG. 18 is an exploded perspective view showing a first example of the shape of a terminal welding portion of the electrode current collector for lamination in a cell and the laminating direction according to the present invention.
FIG. 19 is an exploded perspective view showing a second example of a shape of a terminal welding portion of a lamination electrode current collector in a cell and a lamination direction according to the present invention.
FIG. 20 is a diagram showing an example of an arrangement of stacked electrodes in a cell.
FIG. 21 is a diagram showing another example of the arrangement of the laminated electrodes in the cell.
FIG. 22 is a diagram showing another example of the arrangement of the laminated electrodes in the cell.
FIG. 23 is an explanatory view showing an example of shapes and arrangements of a positive electrode terminal and a negative electrode terminal in a conventional film-type battery.
FIG. 24 is a diagram showing a cross section along the line VII-VII of the example shown in FIG. 20;
FIG. 25 is a diagram showing a cross section along the line VI-VI of the example shown in FIG. 20;
FIG. 26 is a diagram showing a state in which a cell is fixed to a test device for an impact test. (I) is a plan view (top view), and (II) is a right side view of (I).
[Explanation of symbols]
1 positive electrode
2 Negative electrode
1a Current collector (positive electrode)
2a current collector (negative electrode)
1b Positive terminal
2b Negative electrode terminal
1c lead wire fixing screw (positive electrode)
2c lead wire fixing screw (negative electrode)
1d positive electrode tab
2d negative electrode tab
3 separator
4 Exterior laminate film
5. Exterior laminate film (deep drawing)
6 Terminal support
7 Lithium electrode
7a Lithium electrode current collector
7b Lithium electrode lead terminal (drawing part)
8 conductor
8a conductor
10. Lamination unit of film type cell of the present invention
11 General film type cell stacking unit
12 Lead wire
13 plywood
14 Terminal fixing plate
15 Terminal fixing holding plate
16 Fixing screw
101 positive electrode
102 Negative electrode
101a positive electrode current collector
102a negative electrode current collector
101b Positive terminal
102b Negative electrode terminal
103 separator
104 Exterior laminate film
105 Exterior laminate film (deep drawing)
110 Conventional Film Cell
500 plywood
510 terminal fastener
A Heat-fused part between positive electrode terminal and exterior film
B Heat-fused part between negative electrode terminal and exterior film
C Heat-sealed part of exterior film
A 'Welded part of positive electrode current collector terminal and positive electrode terminal (surface)
A''Welded part of the terminal of the positive electrode current collector and the positive terminal (back side)
B 'Negative electrode current collector terminal weld and negative electrode terminal weld (surface)
B '' Negative electrode current collector terminal weld and negative electrode terminal weld (back side)
E Heat-sealed part of positive or negative terminal and exterior laminate film

Claims (7)

A power storage device including: a power storage unit including at least one pair of a positive electrode and a negative electrode; an exterior film that covers and seals the power storage unit; and a connection terminal to the outside of the positive electrode and the negative electrode. The films are at least partially overlapped and sealed, and the connection terminals of the positive electrode and the negative electrode are exposed to the outside from the time when the outer films are overlapped, and the exposed portions of the connection terminals that are exposed to the outside are plural. A film-type power storage device in which a part of the divided exposed portion is disposed on one surface of the seal portion and the other portion is disposed on the other surface of the seal portion. The film-type power storage device according to claim 2, wherein an exposed portion of the connection terminal is vertically divided. The film-type power storage device according to claim 3, wherein the connection terminal is formed by stacking two sheets, and each sheet is divided into upper and lower parts. The film-type power storage device according to claim 2, wherein an exposed portion of the connection terminal is divided into right and left. The positive electrode active material is a material capable of reversibly supporting lithium ions and / or anions, the negative electrode active material is a material capable of reversibly supporting lithium ions, and the capacitance per unit weight of the negative electrode active material. Has at least three times the capacitance per unit weight of the positive electrode active material, the weight of the positive electrode active material is larger than the weight of the negative electrode active material, and a lithium electrode for preliminarily supporting lithium on the negative electrode is provided on the power storage unit. The film-type power storage device according to any one of claims 1 to 4, wherein: The power storage device includes a positive electrode current collector and a negative electrode current collector, each current collector has a hole penetrating on the front and back surfaces, and the lithium electrode capable of electrochemically supplying lithium to the negative electrode has a negative electrode and a negative electrode. The film-type power storage device according to claim 5, wherein the film-type power storage device faces a positive electrode. The film-type power storage device according to claim 5 or 6, wherein the active material of the negative electrode is an insoluble and infusible substrate having a polyacene-based skeleton structure in which the atomic ratio of hydrogen atoms / carbon atoms is 0.50 to 0.05. .

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