JP4043675B2

JP4043675B2 - Carbon material activation device, carbon material activation method, and electric double layer capacitor manufacturing method

Info

Publication number: JP4043675B2
Application number: JP37094799A
Authority: JP
Inventors: 邦宏松田; 廸夫岡村
Original assignee: Casio Computer Co Ltd
Current assignee: Casio Computer Co Ltd
Priority date: 1999-12-27
Filing date: 1999-12-27
Publication date: 2008-02-06
Anticipated expiration: 2019-12-27
Also published as: JP2001180922A

Description

【０００１】
【発明の属する技術分野】
本発明は、電気二重層コンデンサの分極性電極などに用いられる炭素材料の賦活装置、炭素材料の賦活方法及び電気二重層コンデンサの製造方法に関するものである。
【０００２】
【従来の技術】
電気二重層コンデンサの分極性電極に適用される活性炭は、微細な孔を多数内含することで大きい比表面積を持つ多孔性の構造であり、この活性炭は炭素化合物からなる炭素材料を賦活して多孔質化することにより得られ、十分大きい静電容量を持つ活性炭を得るために様々な手法の炭素材料の賦活方法が研究されている。
そこで、大きい静電容量を持つ活性炭を得る方法として、電気的賦活方法が用いられている。電気的賦活方法では、セパレータの両面にそれぞれ正極用の分極性電極となる炭素材料シート及びこの炭素材料シートと同程度の厚さの負極用の分極性電極となる炭素材料シートを配置し、さらにこれら炭素材料シートの外面にそれぞれ外部接続用配線に接続された集電極を配置し、炭素材料シート内に電解液を含浸させた後、これら集電極に所定の電圧を印加し、炭素材料シートに電界を印加することにより炭素材料シートの賦活を行い比表面積を大きくすることで、そのまま電気二重層コンデンサとして完成させていた。ここで賦活電圧は、正極用の炭素材料シート及び負極用の炭素材料シートともにほぼ同程度の電圧に分圧されているが、シートに印加される電圧値はある程度高くないと賦活の進行が極端に遅く、印加時間がある程度長い方がより大きい静電容量の電気二重層コンデンサが得られることが確認されている。
【０００３】
【発明が解決しようとする課題】
しかし、電気二重層コンデンサの正極及び負極の分極性電極に適用される未賦活の炭素材料シートの容積比はほぼ１：１で且つ同材料からなり、電解液中で電解されたイオンの電荷量の絶対値は正極側及び負極側で互いに等しいの２枚の炭素材料シートはほぼ同じ電圧値に分圧され、またセル全体に印加される賦活電圧は電気二重層コンデンサの特性劣化電圧未満に制限されていたため、それぞれの炭素材料シートに印加される電圧は高くならず結果として十分大きい静電容量が得ることが困難だった。
本発明は、上記事情に鑑みてなされたもので、賦活電圧による劣化を抑え、任意の静電容量を持たせることのできる炭素材料の賦活装置、炭素材料の賦活方法及び電気二重層コンデンサの製造方法を提供することを目的としている。
【０００４】
【課題を解決するための手段】
上記の課題を解決するため、請求項１記載の炭素材料の賦活装置（例えば図１参照）は、所定の静電容量の補助部材と、一方の面を補助部材に接し、他方の面に賦活対象の炭素材料を配置するセパレータと、前記補助部材及び前記セパレータを収納し、内部を電解液で満たした収納容器と、前記炭素材料及び前記補助部材間に電圧を印加する電源と、を備えることを特徴とする。
【０００５】
この請求項１記載の炭素材料の賦活装置によれば、炭素材料及び補助部材間に印加される賦活電圧が素子劣化電圧未満に抑えても賦活対象の炭素材料により大きい電圧が印加されるため十分大きい静電容量に達するまで賦活することができるので、炭素材料の劣化並びに電解液の分解又は劣化によって賦活効果が低減することを防止できる。特に、補助部材を、上記未賦活の炭素材料よりも静電容量の高くすることで、炭素材料及び補助部材間に印加される電圧のうちの多くが、賦活対象の炭素材料に印加されるので、大きい静電容量を持つ分極性電極を得ることができる。一方、賦活対象の炭素材料シートの高電圧を印加し電気的賦活して炭素材料シートを形成するとこの炭素材料シート内部の細孔に存在する電解液が高電圧により劣化してしまうことがある。この炭素材料シートをそのまま電気二重層コンデンサとして使用すると劣化した電解液により発生される不純物が炭素材料シートを汚染し、結果として素子特性を下げることもある。このため、補助部材の静電容量を炭素材料シートの静電容量より小さくした方がいい場合もある。
なお、炭素材料に分圧される電圧は、電源の電流値又は電圧値並びに補助部材の静電容量に応じて制御され、補助部材の静電容量は、その種類、質量、体積、表面積に応じて設定されることができる。
【０００６】
そして上記の課題を解決するため、請求項４記載の炭素材料の賦活方法は、絶縁体からなるセパレータを挟んで設けられた賦活対象の炭素材料シート及び補助部材を電解液に満たし、前記炭素材料シートおよび前記補助部材間に所定の電圧を印加して賦活するようにしている。
請求項４記載の炭素材料の賦活方法によれば、炭素材料シート及び補助部材間に印加される賦活電圧が素子劣化電圧未満に抑えても賦活対象の炭素材料シートにより大きい電圧が印加されるため十分大きい静電容量に達するまで賦活することができるので、炭素材料の劣化並びに電解液の分解又は劣化によって賦活効果が低減することを防止できる。
【０００７】
そして請求項８記載の発明では、電気二重層コンデンサの製造方法において、絶縁体からなるセパレータを挟んで設けられた賦活対象の第１炭素材料シート及び補助部材を電解液に満たし、前記第１炭素材料シートおよび前記補助部材間に電圧を印加して電気的賦活された第１炭素材料シートを形成し、絶縁体からなるセパレータを挟んで設けられた賦活対象の第２炭素材料シート及び補助部材を電解液に満たし、前記第２炭素材料シートおよび前記補助部材間に電圧を印加して電気的賦活された第２炭素材料シートを形成し、前記電気的賦活された第１炭素材料シート及び前記電気的賦活された第２炭素材料シートをセパレータを介して配置するようにしたものである。
請求項８記載の発明では、第１炭素材料シート及び第２炭素材料シートをそれぞれ、別途電気的賦活するのでそれぞれ任意の電圧を印加することができ、最適の静電容量に設定することができる。電気的賦活に用いられる補助部材は、第１炭素材料シート用及び第２炭素材料シート用と別にしても同じでもよい。電気二重層コンデンサとして賦活された第１炭素材料シート及び賦活された第２炭素材料シートに挟まれるセパレータは、第１炭素材料シート又は第２炭素材料シートを電気的賦活したときに用いられるセパレータを用いてもよいし、電気的賦活時に用いられていないセパレータでもよい。
【０００８】
【発明の実施の形態】
本実施の形態の炭素材料の賦活装置及び炭素材料の賦活方法は、図１に示すように、絶縁体からなるセパレータ３を挟んで、一方に電気二重層コンデンサの分極性電極に用いられる電気的に賦活された炭素材料シートとなる未賦活の炭素材料シート（炭素材料）１を、他方に、炭素材料シート１を賦活するための対極となる補助シート（補助部材）２を配し、前記賦活対象の炭素材料シート１および補助シート２の上にそれぞれ、金属箔からなる同じ表面積の集電極４、４を配し、前記セパレータ３、賦活対象の炭素材料シート１、補助シート２、および集電極４、４とを、収納容器（セル）６で覆い、この収納容器６の内部には電解液５を充填した上で、前記集電極４、４を、電気回路１１を通じて収納容器６外部の定電流源（電源）１２に接続することで、賦活対象の炭素材料シート１及び補助シート２間に電圧を印加するものである。ここで補助シート２は、炭素材料シート１と同様に炭素化合物又は様々な方法で賦活された活性炭或いはこれらの混合物から構成されていてもよい。シート１、２が集電極４と接触する面積並びにセパレータ３と接触する面積は全て同じになるように設定されている。また、この集電極４、４は、本実施の形態の炭素材料の賦活方法により得られる電気二重層コンデンサの集電極である必要はない。
【０００９】
ここで、賦活対象の炭素材料シート１と非賦活対象の補助シート２は、同材料を用いるが、図１に示すように、賦活対象の炭素材料シート１に対し、補助シート２の量を十分多くする。したがって、炭素材料シート１は補助シート２より薄い構造になり、定電流源１２から集電極４，４間の炭素材料シート１及び補助シート２に一定時間電流を流すと、正負両極側の炭素材料の電位は図２に示すように、炭素材料シート１並びに補助シート２の容量に応じて分圧される。詳述すると、電解液中で電解される電荷の量の絶対値は、炭素材料シート１側と補助シート２側でほぼ等しいため、両者に分圧される電圧の比は、両者の容量の比に依存され、容量のより小さい側により大きい電圧が分圧されることになる。このように、より静電容量の小さい炭素材料シート１により絶対値が大きい電圧が印加されるという相乗効果により補助シート２の単位体積当たり印加される電圧（絶対値）に対する炭素材料シート１の単位体積当たり印加される電圧（絶対値）の比率は、補助シート２全体に印加される電圧（絶対値）に対する炭素材料シート１全体に印加される電圧（絶対値）の比率より大きい。このためセル全体の賦活電圧を上げることなく炭素材料シート１の賦活をより促進させて電気的に賦活された炭素材料シート１とし、静電容量を大きくすることができる。
【００１０】
このようにして、電気二重層コンデンサの正極側分極性電極および負極側分極性電極となる複数の電気的に賦活された炭素材料シート１を、それぞれ補助シート２を用いて電気賦活して、電気的に賦活された炭素材料シート１からなる正極側分極性電極および負極側分極性電極をセパレータで挟み、両外側にアルミニウム等でなる集電極を設け、これを絶縁容器で覆い、電気的に賦活された炭素材料シート１内を十分電解液で満たした後封止して電気二重層コンデンサを製造する。このとき賦活後に電気的に賦活された炭素材料シート１内に残された電解液を排出し、新しい電解液で電気的に賦活された炭素材料シート１内を満たしてもよい。
【００１１】
本実施の形態の炭素材料の賦活装置及び炭素材料の賦活方法によれば、炭素材料シート１に分圧される電圧は、定電流源１２の電流値又は電圧値並びに補助部材シート２の静電容量に応じて制御され、補助部材シート２の静電容量は、その種類、質量、体積、表面積に応じて設定されることができる。
また、賦活用分極性電極として、賦活対象の炭素材料シート１よりも静電容量の大きい非賦活対象の炭素材料２を用いることで、両集電極４，４間に印加される電圧の大部分が、賦活対象の炭素材料１に印加されるので、大きい静電容量を持つ電気的に賦活された炭素材料を得ることができる。また、両集電極４，４間に印加される電圧が比較的小さくても賦活対象の炭素材料シート１を賦活することができるので、電気的に賦活された炭素材料シート１及び電解液５が劣化を起こすことを防止するによって賦活効果が低減することを防止できる。
【００１２】
また、電気二重層コンデンサとしては使用する必要のない補助シート２は、複数の炭素材料シート１の賦活用に繰り返し用いることができるので、図１の炭素材料シート１を除くシステムを賦活装置として連続して炭素材料シート１の賦活に用いることができる。補助シート２は炭素材料シート１の賦活前に賦活されたものであっても、賦活されてないものであってもよいが電気的賦活により劣化しにくいものが望ましい。補助シート２に炭素材料を用いると補助シート２は炭素材料シート１の賦活時に賦活している状態なので比表面積が大きいため電解液５中の不純物を吸着しある程度洗浄する作用も兼ね備えている。なお賦活装置における電解液５は賦活するに従い経時劣化するので適宜交換、洗浄した方が望ましい。
【００１３】
なお、上記の実施の形態では、賦活対象の炭素材料シート１の対極側には、補助シート２を配して電気的賦活を行ったが、本発明はこれに限定されることはなく、賦活対象の炭素材料シート１の対極側は、炭素材料以外の材料からなってもよいし、そのような材料と例えば、賦活対象の炭素材料１よりも大きい静電容量を持つ炭素材料以外の材料や、と炭素材料との混合物であってもよい。
また、電気二重層コンデンサの正極側および負極側の分極性電極となる電気的に賦活された炭素材料は、電気的賦活時にいずれも正極側で賦活したが、電解液の種類、炭素材料の種類に応じて、炭素材料シートの電気的賦活を負極側で行い、この電気的に賦活された炭素材料シートを、電気二重層コンデンサの正極および負極に使用してもよい。この場合、賦活対象の炭素材料シートを負極側に配し、補助シートを正極側に配して、炭素材料シートの電気的賦活を行う。
その他、具体的な詳細などについても適宜に変更可能であることは勿論である。
【００１４】
【実施例】
本発明の炭素材料の賦活方法にて、炭素材料シートを賦活し、電気二重層コンデンサの正極側分極性電極および負極側分極性電極としてコンデンサＡを作製した。コンデンサＡの正極側および負極側の分極性電極（Ａ＋，Ａ−）となる、賦活対象の炭素材料シートは、ともに炭素化合物９８ｗｔ％、ＰＴＦＥ（ポリエチレンテレフタラート）２ｗｔ％の混合物であり、それぞれ賦活用セル内で、賦活対象の炭素材料シートをセパレータの正極側に、補助シートをセパレータの負極側に配し、両炭素材料シートの外面にそれぞれ集電極（賦活用電極）を配し、さらにＰＣ（プロピレンカーボネイト）溶媒に電解質ＴＥＭＡＢＦ₄（トリエチルメチルアンモニウム・テトラフルオロボーレイト）を溶解した２ｍｏｌ／ｌの電解液でセル内部を満たした。セル内の容積は、０．６ｃｍ³とし、それぞれ、次の同条件下で、別々に賦活した。
この炭素材料の賦活条件は、賦活対象の炭素材料シートと補助シートの質量比を１：３とし、定電流源により５ｍＡの定電流を６００００秒流し続け、正負両極間の賦活電圧は最大で３．５Ｖとした。
【００１５】
また、比較対照のため、正極側および負極側の炭素材料シートの質量比を１：１とした実施例とセパレータで互いに離間された同材料からなる正負両極側の炭素材料シートを賦活対象とし、同材料の電解液で満たして封止したセルの炭素材料シートに賦活電圧を加えて、正負両極側の炭素材料シートの賦活を同時に行い、このセルをそのまま正極側分極性電極Ｂ＋および負極側分極性電極Ｂ−とした電気二重層コンデンサＢ（従来の炭素材料の電気的賦活方法）も用意した。炭素材料の電気的賦活時の正負両極間の最大印加電圧は、コンデンサＡの場合と同様に、３．５Ｖとした。なお、賦活用の炭素材料シートの容積を実施例及び比較例ともに等しくするため、セルの容積を０．３ｃｍ³とした。このため定電流源により５ｍＡの定電流を３００００秒流し続けた。
【００１６】
表１に、コンデンサＡ用セルおよびコンデンサＢの炭素材料シートの電気的賦活時の、正負両極における電位配分を示す。
【００１７】
【表１】

【００１８】
表１に示すように、コンデンサＡの正極側電極（Ａ＋）となる炭素材料シートおよび負極側電極（Ａ−）となる炭素材料シートの賦活においては、賦活対象の炭素材料シートの電位上昇量は、補助シートの電位降下量の１．６倍程度である。
【００１９】
表２は、上記の方法により電気的に賦活された炭素材料を正極および負極として電気二重層コンデンサ（コンデンサＡ、コンデンサＢ）を作製して３．５Ｖで充電したときの電位配分を示す。
コンデンサＡとコンデンサＢとの間に、電位配分の差はほとんど見られない。
【００２０】
【表２】

【００２１】
表２に示すように、コンデンサＡとコンデンサＢとの間に、正負両極間の電位配分の差はほとんど見られない。
【００２２】
表３に、コンデンサＡと、コンデンサＢの特性を示す。
【００２３】
【表３】

【００２４】
表３の結果から、コンデンサＡはコンデンサＢよりも内部抵抗が僅かに大きいが、コンデンサＡはコンデンサＢに比べて静電容量が単位重量当たりで１１％、単位体積当たりで１４％大きく、また、蓄積される電力量が単位体積当たりで１４％大きいのに対し、内部抵抗の差は僅かなので、静電容量および蓄積される電力量の大きなコンデンサＡが優れている。
したがって、本発明の炭素材料の賦活方法により賦活した活性炭を、電気二重層コンデンサの正極側および負極側の分極性電極として使用することで、炭素材料の賦活時に正負両極間に印加する電界を高電圧にして劣化することなく、静電容量の大きな電気二重層コンデンサを得ることができた。
【００２５】
【発明の効果】
本発明によれば、炭素材料及び補助部材間に印加される電圧を抑えて賦活対象の炭素材料により大きい電圧が印加されるため十分賦活することができるので、電解液が分解したり劣化を起こすことによって賦活効果が低減することを防止できる。また電気二重層コンデンサの正、負極用の分極性電極となる炭素材料の電気的賦活をそれぞれ単極ごとに高電界下で行うことができるので、大きい静電容量を持つ活性炭を得ることができる。
【図面の簡単な説明】
【図１】本発明の炭素材料の賦活方法の一例を示す概略図である。
【図２】本発明の炭素材料の賦活方法の一例による、賦活対象の炭素材料（炭素材料シート）および補助部材（補助シート）の電位変化を示す図である。
【符号の説明】
１炭素材料（炭素材料シート）
２補助シート（補助部材）
３セパレータ
４集電極
５電解液
６収納容器（セル）
１１電気回路
１２電源（定電流源）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a carbon material activation device, a carbon material activation method, and a method for producing an electric double layer capacitor used for a polarizable electrode of an electric double layer capacitor.
[0002]
[Prior art]
Activated carbon applied to the polarizable electrode of an electric double layer capacitor has a porous structure with a large specific surface area by including many fine pores. This activated carbon activates a carbon material made of a carbon compound. In order to obtain activated carbon having a sufficiently large capacitance obtained by making it porous, various methods for activating carbon materials have been studied.
Therefore, an electrical activation method is used as a method for obtaining activated carbon having a large capacitance. In the electrical activation method, a carbon material sheet serving as a polarizable electrode for a positive electrode and a carbon material sheet serving as a polarizable electrode for a negative electrode having a thickness similar to the carbon material sheet are disposed on both sides of the separator, The collector electrodes connected to the external connection wirings are arranged on the outer surfaces of these carbon material sheets, respectively, and after impregnating the carbon material sheets with the electrolytic solution, a predetermined voltage is applied to these collector electrodes, The carbon material sheet was activated by applying an electric field to increase the specific surface area, thereby completing the electric double layer capacitor as it was. Here, the activation voltage is divided to substantially the same voltage in both the positive electrode carbon material sheet and the negative electrode carbon material sheet, but the activation is extremely advanced unless the voltage applied to the sheet is high to some extent. It is confirmed that an electric double layer capacitor having a larger capacitance can be obtained when the application time is relatively long.
[0003]
[Problems to be solved by the invention]
However, the volume ratio of the unactivated carbon material sheet applied to the polarizable electrodes of the positive and negative electrodes of the electric double layer capacitor is approximately 1: 1 and is made of the same material, and the charge amount of ions electrolyzed in the electrolytic solution The two carbon material sheets with the same absolute value on the positive electrode side and the negative electrode side are divided to almost the same voltage value, and the activation voltage applied to the entire cell is limited to less than the characteristic deterioration voltage of the electric double layer capacitor. Therefore, the voltage applied to each carbon material sheet is not high, and as a result, it is difficult to obtain a sufficiently large capacitance.
The present invention has been made in view of the above circumstances, and suppresses deterioration due to an activation voltage and can provide an arbitrary capacitance, a carbon material activation device, a carbon material activation method, and manufacture of an electric double layer capacitor It aims to provide a method.
[0004]
[Means for Solving the Problems]
In order to solve the above-described problem, the carbon material activation device according to claim 1 (see, for example, FIG. 1) has an auxiliary member having a predetermined capacitance, one surface being in contact with the auxiliary member, and the other surface being activated. A separator for disposing a target carbon material, a storage container storing the auxiliary member and the separator and filled with an electrolyte, and a power source for applying a voltage between the carbon material and the auxiliary member. It is characterized by.
[0005]
According to the activation device of the carbon material according to claim 1, even if the activation voltage applied between the carbon material and the auxiliary member is suppressed to less than the element deterioration voltage, a sufficient voltage is applied to the carbon material to be activated. Since it can activate until it reaches a large capacitance, it can be prevented that the activation effect is reduced due to the deterioration of the carbon material and the decomposition or deterioration of the electrolytic solution. In particular, since the auxiliary member has a higher capacitance than the unactivated carbon material, most of the voltage applied between the carbon material and the auxiliary member is applied to the carbon material to be activated. A polarizable electrode having a large capacitance can be obtained. On the other hand, when a high voltage of a carbon material sheet to be activated is applied and electrically activated to form a carbon material sheet, the electrolyte present in the pores inside the carbon material sheet may be deteriorated by the high voltage. If this carbon material sheet is used as an electric double layer capacitor as it is, impurities generated by the deteriorated electrolyte solution may contaminate the carbon material sheet, resulting in deterioration of device characteristics. For this reason, it may be better to make the capacitance of the auxiliary member smaller than the capacitance of the carbon material sheet.
The voltage divided by the carbon material is controlled according to the current value or voltage value of the power source and the capacitance of the auxiliary member, and the capacitance of the auxiliary member depends on the type, mass, volume, and surface area. Can be set.
[0006]
And in order to solve said subject, the activation method of the carbon material of Claim 4 fills the electrolyte material with the carbon material sheet and auxiliary member of the activation object provided on both sides of the separator which consists of an insulator, The said carbon material A predetermined voltage is applied between the sheet and the auxiliary member for activation.
According to the activation method of the carbon material according to claim 4, even if the activation voltage applied between the carbon material sheet and the auxiliary member is less than the element deterioration voltage, a larger voltage is applied to the carbon material sheet to be activated. Since activation can be performed until a sufficiently large electrostatic capacity is reached, it is possible to prevent the activation effect from being reduced due to deterioration of the carbon material and decomposition or deterioration of the electrolytic solution.
[0007]
According to an eighth aspect of the present invention, in the method for manufacturing an electric double layer capacitor, the first carbon material sheet to be activated and the auxiliary member provided with a separator made of an insulator interposed therebetween are filled with an electrolyte solution, and the first carbon A first carbon material sheet that is electrically activated by applying a voltage between the material sheet and the auxiliary member is formed, and a second carbon material sheet to be activated and the auxiliary member provided with a separator made of an insulator interposed therebetween. An electrically activated second carbon material sheet is formed by applying a voltage between the second carbon material sheet and the auxiliary member to fill the electrolytic solution, and the electrically activated first carbon material sheet and the electricity The activated second carbon material sheet is disposed via a separator.
In the invention according to claim 8, since the first carbon material sheet and the second carbon material sheet are separately electrically activated, an arbitrary voltage can be applied, and the optimum capacitance can be set. . The auxiliary member used for electrical activation may be the same as that used separately from the first carbon material sheet and the second carbon material sheet. The separator sandwiched between the first carbon material sheet activated as the electric double layer capacitor and the activated second carbon material sheet is a separator used when the first carbon material sheet or the second carbon material sheet is electrically activated. A separator that is not used at the time of electrical activation may be used.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIG. 1, the carbon material activation device and the carbon material activation method according to the present embodiment are electrically used for a polarizable electrode of an electric double layer capacitor with a separator 3 made of an insulator interposed therebetween. An unactivated carbon material sheet (carbon material) 1 to be a carbon material sheet activated in the above-described manner, and an auxiliary sheet (auxiliary member) 2 serving as a counter electrode for activating the carbon material sheet 1 are arranged on the other side. On the target carbon material sheet 1 and the auxiliary sheet 2,

collector electrodes

4 and 4 having the same surface area made of metal foil are arranged, respectively, and the separator 3, the carbon material sheet 1 to be activated, the auxiliary sheet 2, and the

current collector electrode

4 and 4 are covered with a storage container (cell) 6, the inside of the storage container 6 is filled with an electrolytic solution 5, and the

collector electrodes

4 and 4 are fixed to the outside of the storage container 6 through an electric circuit 11. Current source (power source) 12 By connecting, in which a voltage is applied between the carbon material sheet 1 and the auxiliary sheet 2 activation target. Here, the auxiliary sheet 2 may be composed of a carbon compound, activated carbon activated by various methods, or a mixture thereof in the same manner as the carbon material sheet 1. The area where the

sheets

1 and 2 are in contact with the collector electrode 4 and the area where they are in contact with the separator 3 are all set to be the same. Further, the

collector electrodes

4 and 4 need not be collector electrodes of an electric double layer capacitor obtained by the carbon material activation method of the present embodiment.
[0009]
Here, the carbon material sheet 1 to be activated and the auxiliary sheet 2 to be deactivated use the same material, but the amount of the auxiliary sheet 2 is sufficient with respect to the carbon material sheet 1 to be activated as shown in FIG. Do more. Therefore, the carbon material sheet 1 has a thinner structure than the auxiliary sheet 2, and when a current is passed from the constant current source 12 to the carbon material sheet 1 and the auxiliary sheet 2 between the

collector electrodes

4 and 4, the carbon material on both the positive and negative sides 2 is divided according to the capacity of the carbon material sheet 1 and the auxiliary sheet 2 as shown in FIG. More specifically, since the absolute value of the amount of electric charge electrolyzed in the electrolytic solution is substantially equal on the carbon material sheet 1 side and the auxiliary sheet 2 side, the ratio of the voltages divided by both is the ratio of the capacity of both. The higher voltage is divided on the smaller side of the capacitance. Thus, the unit of the carbon material sheet 1 with respect to the voltage (absolute value) applied per unit volume of the auxiliary sheet 2 due to the synergistic effect that a voltage having a large absolute value is applied by the carbon material sheet 1 having a smaller capacitance. The ratio of the voltage (absolute value) applied per volume is larger than the ratio of the voltage (absolute value) applied to the entire carbon material sheet 1 to the voltage (absolute value) applied to the entire auxiliary sheet 2. For this reason, without increasing the activation voltage of the whole cell, the activation of the carbon material sheet 1 can be further promoted to make the carbon material sheet 1 electrically activated, and the capacitance can be increased.
[0010]
In this way, a plurality of electrically activated carbon material sheets 1 that become the positive electrode side polarizable electrode and the negative electrode side polarizable electrode of the electric double layer capacitor are each electrically activated using the auxiliary sheet 2, The positively polarizable electrode and the negatively polarizable electrode made of activated carbon material sheet 1 are sandwiched between separators, and collector electrodes made of aluminum or the like are provided on both outer sides, covered with an insulating container, and electrically activated. The filled carbon material sheet 1 is sufficiently filled with an electrolytic solution and then sealed to manufacture an electric double layer capacitor. At this time, the electrolytic solution left in the carbon material sheet 1 electrically activated after activation may be discharged, and the carbon material sheet 1 electrically activated with the new electrolytic solution may be filled.
[0011]
According to the carbon material activation device and the carbon material activation method of the present embodiment, the voltage divided into the carbon material sheet 1 is the current value or voltage value of the constant current source 12 and the electrostatic capacity of the auxiliary member sheet 2. It is controlled according to the capacity, and the capacitance of the auxiliary member sheet 2 can be set according to its type, mass, volume, and surface area.
Moreover, most of the voltage applied between the

collector electrodes

4 and 4 can be obtained by using the non-activation target carbon material 2 having a larger capacitance than the activation target carbon material sheet 1 as the activation polarizable electrode. However, since it is applied to the carbon material 1 to be activated, an electrically activated carbon material having a large capacitance can be obtained. Moreover, since the carbon material sheet 1 to be activated can be activated even if the voltage applied between the

collector electrodes

4 and 4 is relatively small, the electrically activated carbon material sheet 1 and the electrolytic solution 5 can be activated. By preventing the deterioration, the activation effect can be prevented from being reduced.
[0012]
Further, since the auxiliary sheet 2 that does not need to be used as an electric double layer capacitor can be repeatedly used for the utilization of the plurality of carbon material sheets 1, the system excluding the carbon material sheet 1 in FIG. Thus, the carbon material sheet 1 can be used for activation. The auxiliary sheet 2 may be activated before activation of the carbon material sheet 1 or may not be activated, but is preferably not easily deteriorated by electrical activation. When a carbon material is used for the auxiliary sheet 2, the auxiliary sheet 2 is activated when the carbon material sheet 1 is activated, and therefore has a large specific surface area, so that it also has an action of adsorbing impurities in the electrolytic solution 5 and cleaning to some extent. In addition, since the electrolyte solution 5 in an activation apparatus deteriorates with time as it is activated, it is desirable to replace and wash as appropriate.
[0013]
In the above embodiment, the auxiliary sheet 2 is arranged on the counter electrode side of the carbon material sheet 1 to be activated for electrical activation. However, the present invention is not limited to this and is activated. The counter electrode side of the target carbon material sheet 1 may be made of a material other than the carbon material, and such a material and, for example, a material other than a carbon material having a larger capacitance than the carbon material 1 to be activated, , And a carbon material may be used.
In addition, the electrically activated carbon material that becomes the polarizable electrodes on the positive electrode side and the negative electrode side of the electric double layer capacitor was activated on the positive electrode side at the time of the electrical activation, but the type of electrolyte and the type of carbon material Accordingly, the carbon material sheet may be electrically activated on the negative electrode side, and the electrically activated carbon material sheet may be used for the positive electrode and the negative electrode of the electric double layer capacitor. In this case, the carbon material sheet to be activated is arranged on the negative electrode side, the auxiliary sheet is arranged on the positive electrode side, and the carbon material sheet is electrically activated.
Of course, specific details can be changed as appropriate.
[0014]
【Example】
The carbon material sheet was activated by the carbon material activation method of the present invention, and a capacitor A was produced as a positive electrode side polarizable electrode and a negative electrode side polarizable electrode of an electric double layer capacitor. The carbon material sheets to be activated, which become the polarizable electrodes (A +, A−) on the positive electrode side and the negative electrode side of the capacitor A, are both a mixture of 98 wt% of carbon compound and 2 wt% of PTFE (polyethylene terephthalate). In the cell, the carbon material sheet to be activated is arranged on the positive electrode side of the separator, the auxiliary sheet is arranged on the negative electrode side of the separator, and collectors (utilizing electrodes) are arranged on the outer surfaces of both carbon material sheets, respectively. The inside of the cell was filled with 2 mol / l of an electrolytic solution in which an electrolyte TEMABF ₄ (triethylmethylammonium tetrafluoroborate) was dissolved in a (propylene carbonate) solvent. The volume in the cell was 0.6 cm ^3, and each was activated separately under the following same conditions.
The activation condition of the carbon material is that the mass ratio of the carbon material sheet to be activated and the auxiliary sheet is 1: 3, and a constant current of 5 mA is continuously supplied from the constant current source for 60000 seconds, and the activation voltage between the positive and negative electrodes is 3 at the maximum. .5V.
[0015]
In addition, for comparison purposes, the positive and negative carbon material sheets made of the same material separated from each other by the separator and the example in which the mass ratio of the carbon material sheet on the positive electrode side and the negative electrode side was 1: 1, were activated, An activation voltage is applied to the carbon material sheet of the cell filled and sealed with the electrolyte solution of the same material, and the carbon material sheet on both the positive and negative electrode sides is activated at the same time, and this cell is directly used as the positive polarizable electrode B + and the negative electrode side component. An electric double layer capacitor B (conventional electrical activation method for carbon material) as a polar electrode B- was also prepared. The maximum applied voltage between the positive and negative electrodes at the time of electrical activation of the carbon material was 3.5 V, as in the case of the capacitor A. In addition, in order to make the volume of the utilized carbon material sheet equal in both the example and the comparative example, the volume of the cell was set to 0.3 cm ³ . Therefore, a constant current of 5 mA was continuously supplied from the constant current source for 30000 seconds.
[0016]
Table 1 shows potential distribution in the positive and negative electrodes at the time of electrical activation of the capacitor A cell and the carbon material sheet of the capacitor B.
[0017]
[Table 1]

[0018]
As shown in Table 1, in the activation of the carbon material sheet serving as the positive electrode (A +) and the carbon material sheet serving as the negative electrode (A−) of the capacitor A, the potential increase amount of the carbon material sheet to be activated is This is about 1.6 times the potential drop of the auxiliary sheet.
[0019]
Table 2 shows potential distribution when an electric double layer capacitor (capacitor A, capacitor B) is manufactured using the carbon material electrically activated by the above method as a positive electrode and a negative electrode and charged at 3.5V.
There is almost no difference in potential distribution between the capacitor A and the capacitor B.
[0020]
[Table 2]

[0021]
As shown in Table 2, there is almost no difference in potential distribution between the positive and negative electrodes between the capacitor A and the capacitor B.
[0022]
Table 3 shows the characteristics of the capacitor A and the capacitor B.
[0023]
[Table 3]

[0024]
From the results in Table 3, capacitor A has a slightly larger internal resistance than capacitor B, but capacitor A has a capacitance 11% per unit weight and 14% greater per unit volume than capacitor B. While the amount of stored electric power is 14% larger per unit volume, the difference in internal resistance is small, so that the capacitor A having a large capacitance and stored electric energy is excellent.
Therefore, by using the activated carbon activated by the carbon material activation method of the present invention as the polarizable electrodes on the positive electrode side and the negative electrode side of the electric double layer capacitor, the electric field applied between the positive and negative electrodes can be increased when the carbon material is activated. An electric double layer capacitor having a large capacitance could be obtained without deteriorating in voltage.
[0025]
【The invention's effect】
According to the present invention, since the voltage applied between the carbon material and the auxiliary member is suppressed and a larger voltage is applied to the carbon material to be activated, it can be activated sufficiently, so that the electrolytic solution is decomposed or deteriorated. Thus, the activation effect can be prevented from being reduced. In addition, since the carbon material used as the polarizable electrode for the positive and negative electrodes of the electric double layer capacitor can be electrically activated for each single electrode under a high electric field, activated carbon having a large capacitance can be obtained. .
[Brief description of the drawings]
FIG. 1 is a schematic view showing an example of a carbon material activation method of the present invention.
FIG. 2 is a diagram showing potential changes of a carbon material (carbon material sheet) to be activated and an auxiliary member (auxiliary sheet) according to an example of the carbon material activation method of the present invention.
[Explanation of symbols]
1 Carbon material (carbon material sheet)
2 Auxiliary sheet (auxiliary member)
3 Separator 4 Collector 5 Electrolyte 6 Storage container (cell)
11 Electric circuit 12 Power supply (constant current source)

Claims

An auxiliary member having a predetermined capacitance;
A separator in which one surface is in contact with the auxiliary member and the carbon material to be activated is disposed on the other surface;
A storage container that stores the auxiliary member and the separator and is filled with an electrolyte; and
A power source for applying a voltage between the carbon material and the auxiliary member;
A carbon material activation device comprising:

In the activation device of the carbon material according to claim 1,
The carbon material activation device is characterized in that a voltage divided by the carbon material is controlled in accordance with a current value or a voltage value of the power source and a capacitance of the auxiliary member.

In the activation apparatus of the carbon material of Claim 1 or 2,
The capacitance of the auxiliary member is set according to the type, mass, volume, and surface area of the carbon material activation device.

A carbon material sheet to be activated and an auxiliary member provided across a separator made of an insulator are filled with an electrolytic solution, and activated by applying a predetermined voltage between the carbon material sheet and the auxiliary member. Carbon material activation method.

In the activation method of the carbon material of Claim 4,
The voltage divided into the carbon material sheet is controlled according to the predetermined voltage and the capacitance of the auxiliary member.

In the activation method of the carbon material of Claim 4 or 5,
The capacitance of the auxiliary member is set according to the type, mass, volume, and surface area of the carbon material.

In the activation method of the carbon material in any one of Claims 4-6,
The method for activating a carbon material, wherein the carbon material sheet includes activated carbon activated to some extent.

The first carbon material sheet to be activated and the auxiliary member provided across the separator made of an insulator were filled with the electrolytic solution, and a voltage was applied between the first carbon material sheet and the auxiliary member to be electrically activated. Forming a first carbon material sheet;
The second carbon material sheet to be activated and the auxiliary member provided across the separator made of an insulator were filled with an electrolytic solution, and a voltage was applied between the second carbon material sheet and the auxiliary member to be electrically activated. Forming a second carbon material sheet;
A method for producing an electric double layer capacitor, wherein the electrically activated first carbon material sheet and the electrically activated second carbon material sheet are disposed via a separator.