JP2001155971A - Electric double-layer capacitor and manufacturing method therefor - Google Patents
Electric double-layer capacitor and manufacturing method thereforInfo
- Publication number
- JP2001155971A JP2001155971A JP33988599A JP33988599A JP2001155971A JP 2001155971 A JP2001155971 A JP 2001155971A JP 33988599 A JP33988599 A JP 33988599A JP 33988599 A JP33988599 A JP 33988599A JP 2001155971 A JP2001155971 A JP 2001155971A
- Authority
- JP
- Japan
- Prior art keywords
- electric double
- separator
- layer capacitor
- porosity
- current collector
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/13—Energy storage using capacitors
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、電解液を含浸した
活性炭質構造体からなる分極性電極を具備する電気二重
層コンデンサおよびその製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric double layer capacitor provided with a polarizable electrode made of an activated carbonaceous structure impregnated with an electrolyte and a method of manufacturing the same.
【０００２】[0002]
【従来技術】電気二重層コンデンサは、電極と電解液の
界面においてイオンの分極によりできる電気二重層を利
用したコンデンサであり、コンデンサと電池の両方の機
能を兼ね備えたものである。2. Description of the Related Art An electric double layer capacitor is a capacitor using an electric double layer formed by polarization of ions at an interface between an electrode and an electrolytic solution, and has both functions of a capacitor and a battery.
【０００３】このような電気二重層コンデンサは、従来
のコンデンサと比較して大容量の充放電が可能であると
ともに、メンテナンスフリーであり、環境汚染を招く恐
れがないことから、小型のメモリーバックアップ電源や
大容量のモータ等の補助電源等として、急速にその需要
が伸びている。[0003] Such an electric double layer capacitor is capable of charging and discharging a larger capacity than conventional capacitors, is maintenance-free, and does not cause environmental pollution. Demand for such devices as auxiliary power sources for motors and large-capacity motors is rapidly increasing.
【０００４】一般に、このような電気二重層コンデンサ
の構造は、複数の電解液を含浸させた活性炭質電極間に
形成された絶縁性の多孔質セパレータにて前記活性炭質
電極間を絶縁するとともに、該積層体の上下面または前
記分極正電極の他の表面に集電体を形成し、該集電体を
通して電気を充放電することにより、該集電体間に静電
容量を発生するものである。In general, such an electric double layer capacitor has a structure in which the activated carbon electrodes are insulated by an insulating porous separator formed between the activated carbon electrodes impregnated with a plurality of electrolytes. A current collector is formed on the upper and lower surfaces of the laminate or on the other surface of the polarized positive electrode, and electricity is charged and discharged through the current collector to generate a capacitance between the current collectors. is there.
【０００５】電気二重層コンデンサは、活性炭質構造体
中に含浸された電解液のイオンが該構造体の空隙部間を
拡散して活性炭表面に吸脱着する、いわゆる電気泳動現
象によって電荷を貯蔵できるものである。かかる電気二
重層コンデンサでは、上記構造体中の空隙部が少なくな
ると、電解液中のイオンが移動速度が極端に低下して内
部抵抗が増大してしまうために内部抵抗を低減せしめる
ためには活性炭質構造体中の空隙率を高める必要があっ
た。[0005] The electric double layer capacitor can store charges by the so-called electrophoresis phenomenon, in which ions of the electrolyte impregnated in the activated carbonaceous structure diffuse between gaps of the structure and adsorb and desorb on the activated carbon surface. Things. In such an electric double-layer capacitor, when the number of voids in the structure is reduced, the movement speed of ions in the electrolytic solution is extremely reduced and the internal resistance is increased. Therefore, activated carbon is required to reduce the internal resistance. It was necessary to increase the porosity in the porous structure.
【０００６】一方、電気二重層コンデンサに電気を供給
または取り出しのために活性炭質構造体に隣接して集電
体を配設するが、両者間での接触抵抗を低減するには両
者間の接触面積を増す必要があるために、例えば、特開
平３−２０１５１９号公報によれば、活性炭微粒子を焼
結結合せしめた互いに密度の異なる第１、２活性炭から
なる活性炭質電極を分極性電極とし、密度の高い第２活
性炭の面を集電体に密着させて、分極性電極と集電体間
の接触抵抗を低減できることが提案されている。On the other hand, a current collector is provided adjacent to the activated carbonaceous structure for supplying or extracting electricity to or from the electric double layer capacitor. To reduce the contact resistance between the two, a contact between the two is required. In order to increase the area, for example, according to Japanese Patent Application Laid-Open No. Hei 3-201519, an activated carbon electrode composed of first and second activated carbons having mutually different densities obtained by sintering activated carbon fine particles is used as a polarizable electrode. It has been proposed that the surface of the second activated carbon having high density can be brought into close contact with the current collector to reduce the contact resistance between the polarizable electrode and the current collector.
【０００７】[0007]
【発明が解決しようとする課題】しかしながら、特開平
３−２０１５１９号公報のように密度の異なる２種類の
活性炭質構造体を用いると、炭化時の収縮率が異なるた
めに積層界面にクラック等が発生し、クラック部に浮遊
炭素が生じてしまい、これが電気泳動により分極性電極
内を移動してセパレータを透過して反対極の分極性電極
に移動してリーク電流を発生したり、ショート等を起こ
し自己放電が大きくコンデンサの静電容量を低下させる
という問題があった。However, when two types of activated carbonaceous structures having different densities are used as disclosed in JP-A-3-201519, cracks and the like are formed at the lamination interface due to different shrinkage rates during carbonization. Then, floating carbon is generated in the crack part, which moves inside the polarizable electrode by electrophoresis, passes through the separator, moves to the opposite polarizable electrode, and generates a leak current, short circuit, etc. There is a problem that self-discharge is large and the capacitance of the capacitor is reduced.
【０００８】従って、本発明の目的は、電解液の移動、
拡散がスムーズで、かつ集電体に対して接触抵抗が小さ
くできることによって内部抵抗を低減できるとともに、
活性炭質構造体にクラック等の発生しない電気二重層コ
ンデンサを得ることにある。Accordingly, an object of the present invention is to move an electrolyte,
Diffusion is smooth and the contact resistance to the current collector can be reduced, so that the internal resistance can be reduced,
An object of the present invention is to provide an electric double layer capacitor in which cracks and the like do not occur in an activated carbonaceous structure.
【０００９】[0009]
【課題を解決するための手段】本発明者等は、前記課題
に対して検討した結果、所定の固さを有する活性炭を含
有する造粒粉末に対して上下面から圧力を付与して成形
し、該成形体の加圧面に平行な一方の加圧面を除く一部
分を除去することによって、該成形体の空隙率が前記一
方の加圧面から他方の表面に向かって小さくでき、この
活性炭質構造体の前記一方の加圧面に集電体を積層し、
また前記他方の表面にセパレータを積層することによっ
て、前記活性炭質構造体の空隙率が前記集電体接着面か
ら前記セパレータ接着面に向かって小さくできるととも
に、集電体に対して接触抵抗を小さくできる結果、内部
抵抗を低減できることから、急速充放電時の電圧低下を
低減できるとともに、活性炭質構造体にクラック等が発
生することがないことを知見した。Means for Solving the Problems As a result of studying the above-mentioned problems, the present inventors have found that granulated powder containing activated carbon having a predetermined hardness is formed by applying pressure from above and below. By removing a part except one pressing surface parallel to the pressing surface of the molded body, the porosity of the molded body can be reduced from the one pressing surface to the other surface, and the activated carbonaceous structure Laminating a current collector on the one pressing surface of the above,
Further, by laminating a separator on the other surface, the porosity of the activated carbonaceous structure can be reduced from the current collector bonding surface toward the separator bonding surface, and the contact resistance with respect to the current collector is reduced. As a result, it has been found that since the internal resistance can be reduced, the voltage drop during rapid charge / discharge can be reduced, and no cracks or the like occur in the activated carbonaceous structure.
【００１０】すなわち、本発明の電気二重層コンデンサ
は、電解液を含浸した活性炭質構造体からなる分極性電
極と、該分極性電極の上下面にそれぞれ積層された集電
体およびセパレータとを具備するものであって、前記活
性炭質構造体の空隙率が前記集電体積層面から前記セパ
レータ積層面に向かって小さいことを特徴とするもので
ある。That is, the electric double layer capacitor of the present invention comprises a polarizable electrode comprising an activated carbonaceous structure impregnated with an electrolytic solution, and a current collector and a separator which are respectively laminated on the upper and lower surfaces of the polarizable electrode. Wherein the porosity of the activated carbonaceous structure decreases from the current-collector laminated surface to the separator-laminated surface.
【００１１】また、本発明の電気二重層コンデンサの製
造方法は、（ａ）活性炭粉末と有機樹脂とを混合し、上
下面から圧力を付与して成形する工程と、（ｂ）該成形
体の加圧面に平行に、一方の加圧面を除く一部分を除去
して、該成形体の空隙率が前記一方の加圧面から他方の
表面に向かって小さくなるようにする工程と、（ｃ）前
記（ｂ）工程で得られた成形体を炭化熱処理して活性炭
質構造体を作製する工程と、（ｄ）前記（ｃ）工程で得
られた活性炭質構造体の空隙率の高い面にセパレータを
積層し、かつ空隙率の低い面に集電体を積層する工程
と、（ｅ）前記活性炭質構造体内に電解液を含浸する工
程とを具備することを特徴とするものである。Further, the method for producing an electric double layer capacitor of the present invention comprises: (a) a step of mixing activated carbon powder and an organic resin and applying pressure from upper and lower surfaces to form; (C) removing a part except for one of the pressing surfaces in parallel with the pressing surface so that the porosity of the molded body decreases from the one pressing surface toward the other surface; b) a step of carbonizing and heat-treating the molded article obtained in the step to prepare an activated carbonaceous structure; and (d) laminating a separator on the surface of the activated carbonaceous structure obtained in the step (c) having a high porosity. And a step of laminating a current collector on a surface having a low porosity, and (e) a step of impregnating the activated carbonaceous structure with an electrolytic solution.
【００１２】[0012]
【発明の実施の形態】本発明の電気二重層コンデンサの
一例を概略断面図である図１に基づいて説明する。図１
によれば、電気二重層コンデンサ１は、電解液を含浸し
た２枚の分極性電極（以下、電極と略す。）２、２間に
絶縁性の多孔質セパレータ（以下、セパレータと略
す。）３が配設され、その電極２、２のセパレータ３接
触面以外の他の表面にはそれぞれ集電体４が積層されて
いる。DESCRIPTION OF THE PREFERRED EMBODIMENTS One example of an electric double layer capacitor of the present invention will be described with reference to FIG. 1 which is a schematic sectional view. FIG.
According to this, the electric double layer capacitor 1 includes an insulating porous separator (hereinafter abbreviated as a separator) 3 between two polarizable electrodes (hereinafter abbreviated as an electrode) 2 and 2 impregnated with an electrolytic solution. And a current collector 4 is laminated on each of the surfaces of the electrodes 2 and 2 other than the contact surface of the separator 3.
【００１３】電極２を構成する活性炭質構造体は、高い
比表面積を有する活性炭粒子と、該活性炭粒子を結合す
るための結合剤として配合され、炭化処理を施された炭
素成分とからなるものであり、活性炭が焼結によって固
着していることが望ましい。また、コンデンサの高静電
容量を維持しつつ、構造体として必要な強度を得るため
には、電極２の比表面積が１０００〜１８００ｍ2／ｇ
であることが望ましい。The activated carbonaceous structure constituting the electrode 2 is composed of activated carbon particles having a high specific surface area and a carbon component which has been blended as a binder for binding the activated carbon particles and has been subjected to a carbonization treatment. Yes, it is desirable that the activated carbon is fixed by sintering. Further, in order to obtain the necessary strength as a structure while maintaining the high capacitance of the capacitor, the specific surface area of the electrode 2 should be 1000 to 1800 m 2 / g.
It is desirable that
【００１４】なお、結合剤として添加される炭素成分
は、活性炭粒子間に存在するが、各活性炭層中に占める
割合が、５〜５０重量％であることが望ましく、これに
より活性炭粒子間の焼結性および結合性を高めることが
できる。The carbon component added as a binder exists between the activated carbon particles, but preferably accounts for 5 to 50% by weight of each activated carbon layer. Bonding and bonding can be increased.
【００１５】本発明によれば、電極２の空隙率が集電体
接触面からセパレータ接触面に向かって小さいことが大
きな特徴であり、これによって、電極２の集電体４接触
面での空隙率が小さくでき、電極２と集電体４との接触
面積が増加することから、電極２と集電体４間の接触抵
抗を低減することができるとともに、電極２のセパレー
タ３側では空隙率が大きいことから、電解液の拡散、移
動が瞬時に起き、大容量の放電によっても内部抵抗が増
大することなく、ＩＲドロップ、すなわち放電時の電圧
低下が抑制できる。According to the present invention, it is a major feature that the porosity of the electrode 2 decreases from the current collector contact surface to the separator contact surface. As the contact ratio between the electrode 2 and the current collector 4 increases, the contact resistance between the electrode 2 and the current collector 4 can be reduced, and the porosity on the separator 3 side of the electrode 2 can be reduced. Is large, the diffusion and movement of the electrolytic solution occur instantaneously, and the IR drop, that is, the voltage drop at the time of discharge can be suppressed without increasing the internal resistance even by a large-capacity discharge.
【００１６】なお、電極２の集電体４積層面での空隙率
ｂ1は、３５〜４０％、電極２のセパレータ３積層面で
の空隙率ｂ2は、４２〜５０％であることが望ましく、
また、図２に示す電極の集電体４積層面からの距離ｒと
空隙率ｂとの関係のようにｒがゼロ付近、すなわち集電
体４積層面では空隙率ｂの変化が急激であり、ｒ＝（１
／６）ｔ（ｔ：電極２の厚み）以上では、空隙率ｂがほ
とんど変化しないことが望ましい。さらに、集電体４積
層面の空隙率ｂ1とセパレータ３積層面の空隙率ｂ2との
比（ｂ1／ｂ2）が、０．７〜０．８であることが望まし
い。The porosity b 1 of the electrode 2 on the surface of the current collector 4 is 35 to 40%, and the porosity b 2 of the electrode 2 on the surface of the separator 3 is 42 to 50%. Desirably,
Further, as shown in the relationship between the distance r of the electrode from the current collector 4 laminated surface and the porosity b shown in FIG. 2, r is near zero, that is, the porosity b changes rapidly on the current collector 4 laminated surface. , R = (1
/ 6) Above t (t: the thickness of the electrode 2), it is desirable that the porosity b hardly changes. Furthermore, the ratio of the porosity of b 2 porosity of the current collector 4 laminated surface b 1 and the separator 3 lamination plane (b 1 / b 2) is desirably 0.7 to 0.8.
【００１７】また、上記構成によれば、水銀圧入法によ
る電極２の嵩密度は、電極２の集電体４接触面で０．６
〜０．７ｇ／ｃｍ3、電極２のセパレータ３接触面で
０．３〜０．４ｇ／ｃｍ3であることが望ましい。According to the above configuration, the bulk density of the electrode 2 by the mercury intrusion method is 0.6 at the contact surface of the electrode 2 with the current collector 4.
~0.7g / cm 3, with a separator 3 contact surface of the electrode 2 is desirably 0.3~0.4g / cm 3.
【００１８】また、電極２、２は、板状であることが望
ましく、また、電極２、２は、コンデンサ製造時の取り
扱いや使用時の振動、衝撃等に耐えうる機械的な信頼性
の点でＪＩＳＲ１６０１に準じた室温における３点曲げ
強度が２９ｋＰａ以上、特に５８ｋＰａ以上であること
が望ましい。The electrodes 2 and 2 are desirably plate-shaped, and the electrodes 2 and 2 have a mechanical reliability that can withstand vibration, shock, and the like during handling and use during the manufacture of the capacitor. The three-point bending strength at room temperature according to JISR1601 is preferably 29 kPa or more, and more preferably 58 kPa or more.
【００１９】さらに、電極２、２の厚みｔは、コンデン
サの集電体間の距離が狭くなるほど静電容量が増加する
ことから、１．５ｍｍ以下、特に１．０ｍｍ以下、さら
に０．５ｍｍ以下であることが望ましい。Further, the thickness t of the electrodes 2 and 2 is 1.5 mm or less, particularly 1.0 mm or less, and more preferably 0.5 mm or less, since the capacitance increases as the distance between the current collectors of the capacitor decreases. It is desirable that
【００２０】電極２中に含浸される電解液としては、硫
酸や硝酸等の水溶液や、プロピレンカーボネート、γ−
ブチロラクトン、Ｎ，Ｎ−ジメチルホルムアミド、エチ
レンカーボネート、スルホラン、３−メチルスルホラン
等の有機溶媒と４級アンモニウム塩、４級スルホニウム
塩、４級ホスホニウム塩等の電解質を組み合わせた有機
溶液が使用可能である。The electrolytic solution impregnated in the electrode 2 includes an aqueous solution of sulfuric acid or nitric acid, propylene carbonate, γ-
An organic solution in which an organic solvent such as butyrolactone, N, N-dimethylformamide, ethylene carbonate, sulfolane, and 3-methylsulfolane is combined with an electrolyte such as a quaternary ammonium salt, a quaternary sulfonium salt, and a quaternary phosphonium salt can be used. .
【００２１】一方、セパレータ３は、パルプやポリエチ
レン、ポリプロピレン等の有機フィルムまたはガラス繊
維不織布等およびセラミックス等により形成され、電極
２間を絶縁するために形成されるものであるが、電極２
内に含有される前記電解液中のイオンを透過させること
ができる多孔質体により形成される。On the other hand, the separator 3 is formed of an organic film such as pulp, polyethylene or polypropylene, a glass fiber nonwoven fabric or the like, ceramics, etc., and is formed to insulate the electrodes 2 from each other.
It is formed of a porous body capable of transmitting ions in the electrolytic solution contained therein.
【００２２】本発明によれば、電極２のセパレータ３接
触面での空隙率が高いことから前記電解液中のイオンが
スムーズに拡散、移動でき、内部抵抗が低減できるとい
う効果がある。According to the present invention, since the porosity of the electrode 2 at the contact surface of the separator 3 is high, the ions in the electrolytic solution can be diffused and moved smoothly, and the internal resistance can be reduced.
【００２３】さらに、集電体４は、導電性を有する導電
性ブチルゴム、アルミニウム板、アルミニウムのプラズ
マ溶射またはステンレス鋼等の金属等により形成され、
電極２との間で電荷をやり取りすることができるが、電
極２との間の接触抵抗低減のためには抵抗率および塑性
変形性の点でアルミニウムであることが望ましい。Further, the current collector 4 is formed of conductive butyl rubber having conductivity, an aluminum plate, aluminum plasma sprayed or metal such as stainless steel, etc.
Although electric charges can be exchanged with the electrode 2, it is preferable to use aluminum in terms of resistivity and plastic deformability in order to reduce contact resistance with the electrode 2.
【００２４】さらに、図１によれば、電極２、２とセパ
レータ３との積層体の外周部には電解液を保持するため
の封止部材５が配設されている。封止部材５は、電極
２，２に含浸される電解液の外部への漏れを防止すると
ともに、電極２，２、セパレータ３、集電体４を固定、
保護するためのものであり、非導電性の材料、例えば、
ポリプロピレン、アクリル等のプラスチックや、ガラ
ス、セラミックス等により形成される。Further, according to FIG. 1, a sealing member 5 for holding the electrolytic solution is provided on the outer peripheral portion of the laminate of the electrodes 2, 2 and the separator 3. The sealing member 5 prevents the electrolyte solution impregnated in the electrodes 2 and 2 from leaking outside and fixes the electrodes 2 and 2, the separator 3 and the current collector 4.
For protection, non-conductive materials, for example,
It is formed of plastics such as polypropylene and acrylic, glass, ceramics and the like.
【００２５】なお、図１では、電極２が正電極および負
電極をなす一対、すなわち２層配設されたものであった
が、本発明はこれに限られるものではなく、集電体４−
電極２−セパレータ３−電極２−集電体４を一単位とし
てこれが複数積層されたものであってもよい。In FIG. 1, the electrode 2 has a pair of a positive electrode and a negative electrode, that is, two electrodes are provided. However, the present invention is not limited to this.
A plurality of the electrodes 2-separators 3-electrodes 2-current collector 4 may be stacked as one unit.
【００２６】次に、本発明の電気二重層コンデンサを作
製方法について説明する。まず、活性炭質構造体を形成
するための窒素吸着法（ＢＥＴ法）による比表面積が１
０００〜３０００ｍ2／ｇの炭素原料を準備する。Next, a method for manufacturing the electric double layer capacitor of the present invention will be described. First, the specific surface area by the nitrogen adsorption method (BET method) for forming the activated carbonaceous structure is 1.
To prepare the carbon raw material of 000~3000m 2 / g.
【００２７】炭素原料としては、ヤシ殻、木材、樹脂等
に対して薬品賦活やガス賦活により作製される活性炭が
高比表面積を有することから好適であり、それ以外にも
カーボンブラック、コールタール、カーボンファイバ
ー、石炭等が使用できる。また、その形状は、球状、フ
レーク状、突起状あるいは不定形があり、特に限定する
ものではなく、また、粉末、粒状、顆粒状のいずれであ
ってもよく、さらに、その粒径は５〜５０μｍであるこ
とが望ましい。As a carbon raw material, activated carbon produced by activating a chemical or a gas with respect to coconut shell, wood, resin, or the like is preferable since it has a high specific surface area. In addition, carbon black, coal tar, and the like can be used. Carbon fiber, coal and the like can be used. The shape is spherical, flake-like, protruding or irregular, and is not particularly limited, and may be any of powder, granular, and granular. Desirably, it is 50 μm.
【００２８】上記の各活性炭原料に所定量の有機バイン
ダを焼成後の炭素成分量が２．５〜７５重量％となる量
で添加、混合する。有機バインダとしては、フェノー
ル、テフロン、コールタール、ポリビニルブチルアルコ
ール（ＰＶＢ）、ポリビニルホルマール（ＰＶＦＭ）等
のポリビニルアセタール、酢酸ビニル等の公知の有機バ
インダが挙げられ、とりわけ成形性および得られる活性
炭質構造体の強度の点から、ポリビニルブチルアルコー
ル（ＰＶＢ）が最も望ましい。A predetermined amount of an organic binder is added to each of the above activated carbon raw materials and mixed in such an amount that the carbon component after firing becomes 2.5 to 75% by weight. Examples of the organic binder include known organic binders such as phenol, teflon, coal tar, polyvinyl acetal such as polyvinyl butyl alcohol (PVB) and polyvinyl formal (PVFM), and vinyl acetate. In terms of body strength, polyvinyl butyl alcohol (PVB) is most desirable.
【００２９】また、上記有機バインダ以外にも可塑剤、
分散剤、溶剤等を添加してもよい。In addition to the organic binder, a plasticizer,
You may add a dispersing agent, a solvent, etc.
【００３０】そして、スプレードライ、市販の高速混合
攪拌機等により造粒する。本発明によれば、該造粒粉が
ある程度の固さを有し、成形時に加圧面とそれ以外の部
分で密度差、すなわち気孔率の差が生じるような造粒粉
であることが望ましく、かかる点から造粒粉のつぶれ性
の指標であるゆるめ嵩密度が０．３〜０．６ｇ／ｃｍ3
であることが望ましい。Then, granulation is performed by spray drying, a commercially available high-speed mixing stirrer, or the like. According to the present invention, it is preferable that the granulated powder has a certain degree of hardness, and is a granulated powder having a difference in density between the pressed surface and the other portion during molding, that is, a difference in porosity, From this point, the loose bulk density which is an index of the crushing property of the granulated powder is 0.3 to 0.6 g / cm 3.
It is desirable that
【００３１】そして、得られた造粒粉を一軸プレス法、
ロール成形法等の上下面から圧力を付与して成形する成
型法により板状またはテープ状等の所定形状に成形す
る。これによって、加圧時に成形体の厚み方向に対して
応力分布が生じ、容易に加圧面とそれ以外の部分での密
度差、気孔率差が得られる。Then, the obtained granulated powder is subjected to a uniaxial pressing method,
It is formed into a predetermined shape such as a plate shape or a tape shape by a molding method in which pressure is applied from the upper and lower surfaces such as a roll molding method. As a result, a stress distribution is generated in the thickness direction of the compact at the time of pressurization, and a density difference and a porosity difference between the pressurized surface and other portions can be easily obtained.
【００３２】ここで、成形体の表面と内部に所望の気孔
率差を生ぜしめ、電気二重層コンデンサの静電容量を高
めるとともに、電極の集電体との接触抵抗を実用上問題
ない程度とするためには、前記成形時の加圧圧力Ｐ（Ｍ
Ｐａ）と成形体の厚みＴ（ｍｍ）との比（Ｔ／Ｐ）が、
１０〜５００であることが望ましい。Here, a desired porosity difference is generated between the surface and the inside of the molded body to increase the capacitance of the electric double layer capacitor, and the contact resistance between the electrode and the current collector is reduced to a level that does not pose a practical problem. In order to achieve this, the pressurizing pressure P (M
Pa) and the thickness (T / P) of the molded body T (mm)
It is desirable to be 10-500.
【００３３】得られた成形体を、非酸化性雰囲気中、６
００〜１２００℃、特に７００〜９００℃で炭化熱処理
して有機バインダ成分を炭化させるとともに、活性炭間
を焼結一体化させる。上述した範囲の焼成温度によって
粒子間を焼結させることができ、構造体としての強度を
維持できるとともに、活性炭の比表面積を所望の範囲に
制御でき、電気二重層コンデンサの静電容量を高めるこ
とができる。The obtained molded body is placed in a non-oxidizing atmosphere at 6
The organic binder component is carbonized by carbonizing heat treatment at 00 to 1200 ° C, particularly 700 to 900 ° C, and the activated carbon is sintered and integrated. The sintering between the particles can be performed by the sintering temperature in the above range, the strength as a structure can be maintained, the specific surface area of the activated carbon can be controlled in a desired range, and the capacitance of the electric double layer capacitor can be increased. Can be.
【００３４】次に、上記焼結体に対して、焼結体の空隙
率が一方の表面から他の表面に向かって連続的に小さく
なるように前記成形時の加圧面に平行な方向に一部を研
削もしくは研磨等により除去する。なお、かかる研削も
しくは研磨等の除去は、前記炭化する前に、除去しても
良い。Next, in the above-described sintered body, the porosity of the sintered body is reduced in one direction parallel to the pressing surface during the molding so that the porosity of the sintered body decreases continuously from one surface to the other surface. The part is removed by grinding or polishing. The removal such as grinding or polishing may be performed before the carbonization.
【００３５】上記活性炭質構造体を２枚作製し、これら
の空隙率が高い面同士がセパレータを介して対向するよ
うに積層し、また該積層体の上下面に集電体を所望によ
り圧着しながら積層した後、外周表面にガスケットを配
置する。そして、前記２枚の活性炭質構造体中に電解液
を含浸させて分極性電極として電気二重層コンデンサを
作製できる。なお、この電解液の含浸はセパレータを積
層する前であってもよい。Two activated carbonaceous structures were prepared, laminated so that their surfaces having a high porosity faced each other with a separator interposed therebetween, and a current collector was pressed on the upper and lower surfaces of the laminate as required. After stacking, a gasket is arranged on the outer peripheral surface. Then, an electrolytic solution is impregnated in the two activated carbonaceous structures, so that an electric double layer capacitor can be manufactured as a polarizable electrode. The impregnation with the electrolytic solution may be performed before the separator is laminated.
【００３６】また、他の方法として、前記活性炭質構造
体と前記セパレータとを先に積層して同時焼成すること
も可能であるが、この場合、前記セパレータは同時焼成
により変質しない耐熱性を有することが望ましい。As another method, the activated carbonaceous structure and the separator can be laminated first and fired simultaneously. In this case, the separator has heat resistance that does not change due to simultaneous firing. It is desirable.
【００３７】[0037]
【実施例】（実施例）まず、比表面積１８００ｍ2／ｇ
を有する活性炭原料に対して、ポリビニルブチルアルコ
ール（ＰＶＢ）を活性炭の比表面積１０００ｍ2／ｇあ
たり６００ｇとなるように添加し、高速混合攪拌機にて
攪拌混合、造粒、篩別した。EXAMPLES (Example) First, a specific surface area of 1800 m 2 / g
Was added to the activated carbon raw material having a weight ratio of 600 g per 1000 m 2 / g of the specific surface area of the activated carbon, and the mixture was stirred and mixed with a high-speed mixing stirrer, granulated, and sieved.
【００３８】得られた造粒粉末のゆるめ嵩密度をＪＩＳ
Ｚ２５０４に基づいて、容器内に粉末を静かに流し入
れ、所定の容積（ｖ）にてすり切った時の容器内の粉末
の重量（ｍ）にて測定し、ｍ／ｖ（ｇ／ｃｍ3）で表さ
れるゆるめ嵩密度を測定し、表１に示した。The loose bulk density of the obtained granulated powder was determined according to JIS.
Based on Z2504, gently pour the powder into the container, measure the weight (m) of the powder in the container when the powder is worn at a predetermined volume (v), and m / v (g / cm 3 ) The loose bulk density represented by was measured and shown in Table 1.
【００３９】次に、上記造粒粉末を表１に示す成形圧
力、成形方法により表１に示す厚みＴ（ｍｍ）に成形
し、所定の長さ、幅にカットした後、該成形体の一方の
表面から加圧面に平行に研磨し、真空中、９００℃で１
０分間炭化熱処理を行った。焼成後、活性炭質構造体の
寸法は縦９０ｍｍ、横６０ｍｍ、電極の厚さ２ｍｍであ
った。なお、実施例の試料についてはクラック等の発生
がなく、いずれも歩留まりが９０％以上と高いものであ
った。Next, the granulated powder was molded into a thickness T (mm) shown in Table 1 by a molding pressure and a molding method shown in Table 1, and cut into a predetermined length and width. Polished in parallel with the pressing surface from the surface of
A carbonization heat treatment was performed for 0 minutes. After firing, the dimensions of the activated carbonaceous structure were 90 mm in length, 60 mm in width, and 2 mm in electrode thickness. The samples of the examples had no cracks or the like, and all had a high yield of 90% or more.
【００４０】上記活性炭質構造体に対して、前記成形体
における加圧面と研磨面でのＳＥＭ観察を行い、画像解
析法によってそれぞれの面での空隙率を測定し、表１に
示した。The activated carbonaceous structure was subjected to SEM observation on the pressurized surface and the polished surface of the molded body, and the porosity on each surface was measured by an image analysis method.
【００４１】次に、得られた活性炭質構造体２枚に対
し、炭酸プロピレン溶液を溶媒とした過塩素酸リチウム
１ｍｏｌ／ｌ電解液を含浸させて分極性電極とした後、
９３ｍｍ×６３ｍｍ×０．１ｍｍのガラス繊維不織布か
らなる多孔質セパレータを介して前記分極性電極の前記
研磨面が対向するように積層し、該積層体の上下面に９
３ｍｍ×６３ｍｍ×０．５ｍｍのアルミニウム製集電体
を積層し、さらに、前記積層体の外周部を絶縁性のブチ
ルゴム製封止部材で固定一体化して、電気二重層コンデ
ンサを作製した。Next, the two activated carbonaceous structures thus obtained were impregnated with a 1 mol / l lithium perchlorate electrolyte using a propylene carbonate solution as a solvent to form polarizable electrodes.
The polarizable electrodes are laminated so that the polished surfaces of the polarizable electrodes face each other via a porous separator made of a glass fiber non-woven fabric of 93 mm × 63 mm × 0.1 mm.
A 3 mm × 63 mm × 0.5 mm aluminum current collector was laminated, and the outer periphery of the laminate was fixed and integrated with an insulating butyl rubber sealing member to produce an electric double layer capacitor.
【００４２】得られた電気二重層コンデンサについて、
図３に示すＩＲドロップ、つまり初期電圧降下から求め
た。すなわち、３Ｖの電圧で３０分間充電した後、３ｍ
Ａ／ｃｍ2の定電流放電法によって放電した際の放電時
間と電圧との関係を示す放電曲線において、コンデンサ
の電圧が初期値（３Ｖ）の６０％および５０％となった
時間ｔ1およびｔ2とを測定し、次式から電極単位重量当
たりの静電容量Ｆ（Ｆ／ｇ）を求めた。 Ｆ＝３ｍＡ×（ｔ2−ｔ1）／（（０．６−０．５）×３
Ｖ×ｗ） ただし、ｗは正、負の分極性電極の総重量である。With respect to the obtained electric double layer capacitor,
It was determined from the IR drop shown in FIG. 3, that is, the initial voltage drop. That is, after charging at a voltage of 3 V for 30 minutes, 3 m
In the discharge curve showing the relationship between the discharge time and the voltage when discharging by the constant current discharge method of A / cm 2 , the times t 1 and t at which the voltage of the capacitor becomes 60% and 50% of the initial value (3 V). 2 and the capacitance F per unit weight of the electrode (F / g) was determined from the following equation. F = 3 mA × (t 2 −t 1 ) / ((0.6−0.5) × 3
V × w) where w is the total weight of the positive and negative polarizable electrodes.
【００４３】また、それぞれの試料の内部抵抗を３０ｍ
Ａ／ｃｍ2の定電流放電法を用い、３Ｖの電圧で充電し
た後、コンデンサの電圧が０Ｖとなるまでの時間Ｔとし
たとき０．１Ｔ時での電圧Ｅiとしたとき、電圧Ｅ＝３
Ｖ−Ｅiで求められる値をＩＲドロップ（初期電圧降
下）とみなし、内部抵抗ＲをＲ＝Ｅ／Ｉ（ここで、Ｉ＝
３０ｍＡ）を算出した。結果は、表１に示した。The internal resistance of each sample was 30 m
Using a constant current discharge method A / cm 2, was charged with a voltage of 3V, when the voltage of the capacitor which has a voltage E i at time 0.1T when the time T until 0V, the voltage E = 3
The value obtained by V-E i regarded as IR drop (initial voltage drop), the internal resistance R R = E / I (where, I =
30 mA) was calculated. The results are shown in Table 1.
【００４４】[0044]
【表１】 [Table 1]
【００４５】表１から明らかなように、プレス成形によ
って得られた成形体を研磨しなかった試料Ｎｏ．９で
は、集電体側面とセパレータ側面での空隙率が同じとな
り、内部抵抗が高く、静電容量が低いものであった。ま
た、プレス成形によって得られた成形体を両面から同じ
厚み研磨した試料Ｎｏ．８では、集電体側面とセパレー
タ側面での空隙率が同じとなり、内部抵抗が高いもので
あった。さらに、プレス成形後、冷間一軸加圧（ＣＩ
Ｐ）成形を行った試料Ｎｏ．１０でも、集電体側面とセ
パレータ側面での空隙率が同じとなり、内部抵抗が高
く、静電容量が低いものであった。As is clear from Table 1, the molded article obtained by press molding was not polished. In No. 9, the porosity on the side of the current collector and the side of the separator were the same, the internal resistance was high, and the capacitance was low. In addition, the molded body obtained by press molding was polished to the same thickness from both sides of Sample No. 1. In No. 8, the porosity on the side of the current collector and the side of the separator were the same, and the internal resistance was high. Furthermore, after press molding, cold uniaxial pressing (CI
P) Sample No. Also in 10, the porosity on the side of the current collector and the side of the separator were the same, the internal resistance was high, and the capacitance was low.
【００４６】これに対して、本発明に従う試料Ｎｏ．１
〜７では、いずれも３ｍＡ／ｃｍ2放電時の静電容量３
０Ｆ／ｇ以上、内部抵抗１６Ω以下の優れた性能を有す
るものであった。On the other hand, the sample No. 1
-7, the electrostatic capacity at discharge of 3 mA / cm 2 was 3
It had an excellent performance of 0 F / g or more and an internal resistance of 16 Ω or less.
【００４７】（比較例）実施例の試料Ｎｏ．９の成形体
と試料Ｎｏ．１０の成形体を積層して焼成したところ、
両者間にクラックが発生する等により歩留まりが６０％
と低いものであった。また、良品について実施例と同様
に評価したところ、静電容量１８Ｆ／ｇ、内部抵抗２７
Ωであった。(Comparative Example) 9 and Sample No. 9 When the 10 compacts were laminated and fired,
60% yield due to cracks between the two
Was low. In addition, when a good product was evaluated in the same manner as in the example, the capacitance was 18 F / g, and the internal resistance was 27 F / g.
Ω.
【００４８】[0048]
【発明の効果】以上詳述したように、本発明の活性炭質
電極およびそれを用いた電気二重層コンデンサ並びにそ
の製造方法によれば、電解液の拡散、移動をスムーズに
行うことができるとともに、集電体に対する接触抵抗を
小さくすることができる結果、内部抵抗の小さい活性炭
質電極が得られ、電気二重層コンデンサの放電時のＩＲ
ドロップを低減することができる。As described in detail above, according to the activated carbonaceous electrode of the present invention, the electric double layer capacitor using the same, and the method of manufacturing the same, the electrolyte can be smoothly diffused and moved, As a result of reducing the contact resistance to the current collector, an activated carbon electrode having a low internal resistance can be obtained, and the IR of the electric double layer capacitor at the time of discharging is reduced.
Drops can be reduced.
【図１】本発明の電気二重層コンデンサの概略断面図で
ある。FIG. 1 is a schematic sectional view of an electric double layer capacitor of the present invention.
【図２】本発明の電気二重層コンデンサの分極性電極に
ついての空隙率の分布の一例を説明するための図であ
る。FIG. 2 is a diagram for explaining an example of a porosity distribution of a polarizable electrode of the electric double layer capacitor of the present invention.
【図３】実施例における内部抵抗の算出方法を説明する
ための図である。FIG. 3 is a diagram for explaining a method of calculating an internal resistance in an embodiment.
１ 電気二重層コンデンサ ２ 分極性電極 ３ 多孔質セパレータ ４ 集電体 ５ 封止部材 DESCRIPTION OF SYMBOLS 1 Electric double layer capacitor 2 Polarized electrode 3 Porous separator 4 Current collector 5 Sealing member
Claims (2)
分極性電極と、該分極性電極の上下面にそれぞれ積層さ
れた集電体およびセパレータとを具備する電気二重層コ
ンデンサであって、前記活性炭質構造体の空隙率が前記
集電体積層面から前記セパレータ積層面に向かって小さ
いことを特徴とする電気二重層コンデンサ。1. An electric double layer capacitor comprising: a polarizable electrode comprising an activated carbonaceous structure impregnated with an electrolytic solution; and a current collector and a separator laminated on upper and lower surfaces of the polarizable electrode, respectively. An electric double layer capacitor, wherein the porosity of the activated carbonaceous structure decreases from the current collector laminated surface to the separator laminated surface.
上下面から圧力を付与して成形する工程と、（ｂ）該成
形体の加圧面に平行に、一方の加圧面を除く一部分を除
去して、該成形体の空隙率が前記一方の加圧面から他方
の表面に向かって小さくなるようにする工程と、（ｃ）
前記（ｂ）工程で得られた成形体を炭化熱処理して活性
炭質構造体を作製する工程と、（ｄ）前記（ｃ）工程で
得られた活性炭質構造体の空隙率の高い面にセパレータ
を積層し、かつ空隙率の低い面に集電体を積層する工程
と、（ｅ）前記活性炭質構造体内に電解液を含浸する工
程とを具備することを特徴とする電気二重層コンデンサ
の製造方法。2. (a) mixing activated carbon powder and an organic resin,
Applying pressure from the upper and lower surfaces to form, and (b) removing a part except one pressing surface in parallel with the pressing surface of the formed body to reduce the porosity of the formed body to the one pressing surface. (C) reducing the size from the surface to the other surface;
A step of producing an activated carbonaceous structure by carbonizing and heat treating the molded article obtained in the step (b); and (d) a separator on the surface of the activated carbonaceous structure obtained in the step (c) having a high porosity. And a step of (e) impregnating the activated carbonaceous structure with an electrolytic solution, comprising the steps of: laminating a current collector on a surface having a low porosity; Method.
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|---|---|---|---|
| JP33988599A JP3786551B2 (en) | 1999-11-30 | 1999-11-30 | Electric double layer capacitor and manufacturing method thereof |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33988599A JP3786551B2 (en) | 1999-11-30 | 1999-11-30 | Electric double layer capacitor and manufacturing method thereof |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006024611A (en) * | 2004-07-06 | 2006-01-26 | Nisshinbo Ind Inc | Electric double layer capacitor |
| JP2008034557A (en) * | 2006-07-27 | 2008-02-14 | Kyoto Univ | Electrode material and its production process |
| JP2009117696A (en) * | 2007-11-08 | 2009-05-28 | Konica Minolta Holdings Inc | Electrode of electrochemical capacitor and electrochemical capacitor |
-
1999
- 1999-11-30 JP JP33988599A patent/JP3786551B2/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006024611A (en) * | 2004-07-06 | 2006-01-26 | Nisshinbo Ind Inc | Electric double layer capacitor |
| JP2008034557A (en) * | 2006-07-27 | 2008-02-14 | Kyoto Univ | Electrode material and its production process |
| JP2009117696A (en) * | 2007-11-08 | 2009-05-28 | Konica Minolta Holdings Inc | Electrode of electrochemical capacitor and electrochemical capacitor |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3786551B2 (en) | 2006-06-14 |
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