JP2010003773A - Electric double layer capacitor - Google Patents

Electric double layer capacitor Download PDF

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JP2010003773A
JP2010003773A JP2008159832A JP2008159832A JP2010003773A JP 2010003773 A JP2010003773 A JP 2010003773A JP 2008159832 A JP2008159832 A JP 2008159832A JP 2008159832 A JP2008159832 A JP 2008159832A JP 2010003773 A JP2010003773 A JP 2010003773A
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double layer
electric double
layer capacitor
insulating film
capacitor
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Masahiro Murata
正浩 村田
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Tokin Corp
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NEC Tokin Corp
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    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/13Energy storage using capacitors

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin type electric double layer capacitor which maintains durability and has low resistance. <P>SOLUTION: Capacitor elements 1 are formed such that a basic cell 8 on the side of an insulating film 2 has smaller area than other basic cells 8, two capacitor elements are disposed opposite to each other with the insulating film 2 interposed therebetween, and lead terminals 5 are electrically connected to the two capacitor elements. When they are sealed with laminate films 3, sealing portions 3a formed by connecting the laminate films 3 and insulating film 2 to each other are put in and provided between the capacitor elements 1 at peripheries of the laminate films 3 perpendicular to the direction where the lead terminals 5 extend. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、電気二重層キャパシタに係り、特に、高い耐電圧を有する電気二重層キャパシタに関する。   The present invention relates to an electric double layer capacitor, and more particularly to an electric double layer capacitor having a high withstand voltage.

電気二重層キャパシタは、Ni水素二次電池やLiイオン二次電池などの二次電池と比べ、急速に充電ができ、大電流で放電することができると共に、1万回以上の充放電を繰り返しても、特性が劣化しないなど、従来の二次電池にはない特長を有している。このため、近年、二次電池の代替用または補助用の電力供給電源として、電気二重層キャパシタに対する期待が高まっている。   Electric double layer capacitors can be charged quickly and discharged with a large current compared to secondary batteries such as Ni-hydrogen secondary batteries and Li-ion secondary batteries, and are repeatedly charged and discharged 10,000 times or more. However, it has features that are not found in conventional secondary batteries, such as no deterioration in characteristics. For this reason, in recent years, there is an increasing expectation for an electric double layer capacitor as an alternative or auxiliary power supply power source for a secondary battery.

また、近年では、業務用ハンディターミナルやパーソナルコンピュータ用通信カードおよび携帯電話等のIT機器の小型化に応じて、内部部品の搭載スペースが限られてきているため、近年の小型携帯製品では薄型で耐久性のある低抵抗のキャパシタの要求が大きい。   In recent years, the space for mounting internal parts has been limited in accordance with the downsizing of IT devices such as business handy terminals, personal computer communication cards, and mobile phones. There is a great demand for durable low-resistance capacitors.

図2は、キャパシタ素子の説明図である。基本セル8は、正極および負極からなる一対の分極性電極9、セパレータ10、正極および負極からなる一対の集電体11から構成される。この基本セル8の正極の集電体11は、集電体リード部6aと電気的に接続され、集電体リード部6aは基本セル8の一端側に延在している。また、基本セル8の負極の集電体11は、集電体リード部6bと電気的に接続され、集電体リード部6bは基本セル8の他端側に延在している。図2のキャパシタ素子1は、基本セル8が並列に接続された例である。キャパシタ素子1は、集電体リード部6aおよび集電体リード部6bが接続された基本セル8が積層されて構成される(例えば、特許文献1参照)。   FIG. 2 is an explanatory diagram of the capacitor element. The basic cell 8 includes a pair of polarizable electrodes 9 composed of a positive electrode and a negative electrode, a separator 10, and a pair of current collectors 11 composed of a positive electrode and a negative electrode. The positive electrode current collector 11 of the basic cell 8 is electrically connected to the current collector lead portion 6 a, and the current collector lead portion 6 a extends to one end side of the basic cell 8. The negative electrode current collector 11 of the basic cell 8 is electrically connected to the current collector lead portion 6 b, and the current collector lead portion 6 b extends to the other end side of the basic cell 8. The capacitor element 1 in FIG. 2 is an example in which basic cells 8 are connected in parallel. The capacitor element 1 is configured by laminating a basic cell 8 to which a current collector lead portion 6a and a current collector lead portion 6b are connected (see, for example, Patent Document 1).

基本セル8は、活性炭を主成分とする分極性電極層を有する一対の上記分極性電極9がセパレータ10を介して対向配置されることで構成され、この分極性電極9には電解液が含浸されている。これにより、分極性電極層と電解液との界面に電気二重層が形成される。電気二重層キャパシタの基本セル8に電圧が印加されると、電気二重層の静電容量に従い電荷が蓄積される。   The basic cell 8 is formed by arranging a pair of polarizable electrodes 9 having a polarizable electrode layer mainly composed of activated carbon through a separator 10, and the polarizable electrodes 9 are impregnated with an electrolyte. Has been. Thereby, an electric double layer is formed at the interface between the polarizable electrode layer and the electrolytic solution. When a voltage is applied to the basic cell 8 of the electric double layer capacitor, charges are accumulated according to the capacitance of the electric double layer.

電気二重層キャパシタの耐電圧は1つの基本セル8当たり2.3〜2.7Vであるため、それ以上の電圧で使用する際は、基本セル8を2個以上直列に接続して耐電圧を高めたキャパシタ素子1を外装体であるラミネートフィルム(図示せず)で覆って、封止することによって、高い耐電圧を有する電気二重層キャパシタが製造されている(例えば、特許文献2〜4参照)。   Since the withstand voltage of an electric double layer capacitor is 2.3 to 2.7 V per basic cell 8, when using at a voltage higher than that, connect two or more basic cells 8 in series to reduce the withstand voltage. An electric double layer capacitor having a high withstand voltage is manufactured by covering and sealing the raised capacitor element 1 with a laminate film (not shown) as an exterior body (see, for example, Patent Documents 2 to 4). ).

特開2002−075806号公報JP 2002-0775806 A 特開2005−093825号公報JP 2005-093825 A 特開2007−173212号公報JP 2007-173212 A 特開2007−317812号公報JP 2007-317812 A

図3は、電気二重層キャパシタの説明図で、図3(a)は比較例の電気二重層キャパシタの上面図、図3(b)は比較例の電気二重層キャパシタの側面図、図3(c)は比較例の電気二重層キャパシタのC−C断面図、図3(d)は比較例の電気二重層キャパシタ構造においてラミネートフィルムと絶縁性フィルムとの接合距離を短くした場合のC−C断面図である。この電気二重層キャパシタは、キャパシタ素子1、絶縁性フィルム2、ラミネートフィルム3、電解液4、リード端子5から構成される。   3A and 3B are explanatory diagrams of the electric double layer capacitor. FIG. 3A is a top view of the electric double layer capacitor of the comparative example, FIG. 3B is a side view of the electric double layer capacitor of the comparative example, and FIG. FIG. 3C is a cross-sectional view of the electric double layer capacitor of the comparative example taken along the line C-C, and FIG. 3D is a cross sectional view of the electric double layer capacitor structure of the comparative example when the bonding distance between the laminate film and the insulating film is shortened. It is sectional drawing. The electric double layer capacitor includes a capacitor element 1, an insulating film 2, a laminate film 3, an electrolytic solution 4, and lead terminals 5.

図3に示した比較例の電気二重層キャパシタにおいては、絶縁性フィルム2を中央に挟んでラミネートフィルム3で封止される。絶縁性フィルム2で区切られた2個の空間にはキャパシタ素子1がそれぞれ挿入される。挿入された2個のキャパシタ素子1の基本セル8は、それぞれ直列に接続され、さらに2個のキャパシタ素子1は並列にリード端子5で電気的に接続される。   In the electric double layer capacitor of the comparative example shown in FIG. 3, the insulating film 2 is sandwiched in the center and sealed with the laminate film 3. Capacitor elements 1 are respectively inserted into the two spaces separated by the insulating film 2. The basic cells 8 of the two inserted capacitor elements 1 are respectively connected in series, and the two capacitor elements 1 are further electrically connected in parallel by the lead terminals 5.

上記2個のキャパシタ素子1は、絶縁性フィルム2で隔離されているため、封止されるラミネートフィルム3内での電気的な接触はなく、図3(b)に示した電気二重層キャパシタの端部におけるラミネートフィルム3の外部の溶接部7で、溶接により電気的に並列接続される。   Since the two capacitor elements 1 are separated by the insulating film 2, there is no electrical contact in the laminated film 3 to be sealed, and the electric double layer capacitor shown in FIG. Electrical connection is made in parallel by welding at a weld 7 outside the laminate film 3 at the end.

この電気二重層キャパシタは、図3(b)、図3(c)に示すように、キャパシタ素子1、絶縁性フィルム2、電解液4、リード端子5、ラミネートフィルム3から構成され、電解液4が含浸されたキャパシタ素子1がラミネートフィルム3で密封されている。そのため、図3(c)に示した電気二重層キャパシタの左右の両短部は、上下2枚のラミネートフィルム3を強固に接着する必要がある。   As shown in FIGS. 3B and 3C, the electric double layer capacitor is composed of a capacitor element 1, an insulating film 2, an electrolytic solution 4, a lead terminal 5, and a laminate film 3, and the electrolytic solution 4 The capacitor element 1 impregnated with is sealed with a laminate film 3. Therefore, it is necessary to firmly bond the upper and lower laminate films 3 to the left and right short portions of the electric double layer capacitor shown in FIG.

また、図3(c)と同じ耐電圧を持つ電気二重層キャパシタで、薄型のまま低抵抗なものにしようとすると、図3(d)の電気二重層キャパシタように、キャパシタ素子1を分離させるための絶縁性フィルム2とラミネートフィルム3との接着幅であるシール幅12を、図3(c)のシール幅12よりも小さくすることが考えられるが、シール幅12を小さくしてしまうと、絶縁性フィルム2とラミネートフィルム3の接着強度が不十分となり、電気特性不良や湿気や水分等の進入による耐久性の悪化という不具合が生じてしまうという問題があった。   In addition, when the electric double layer capacitor having the same withstand voltage as in FIG. 3C is to be made thin and low in resistance, the capacitor element 1 is separated as in the electric double layer capacitor of FIG. For this reason, it is conceivable to make the seal width 12 that is the adhesive width between the insulating film 2 and the laminate film 3 smaller than the seal width 12 of FIG. 3C, but if the seal width 12 is reduced, There is a problem that the adhesive strength between the insulating film 2 and the laminate film 3 becomes insufficient, resulting in defects such as poor electrical characteristics and deterioration of durability due to the ingress of moisture, moisture, and the like.

本発明は、上記の点に鑑みてなされたもので、薄型の電気二重層キャパシタで、耐久性を維持した低抵抗の電気二重層キャパシタを提供することを目的とする。   The present invention has been made in view of the above points, and an object of the present invention is to provide a low-resistance electric double layer capacitor that maintains durability with a thin electric double layer capacitor.

本発明は、正極および負極からなる一対の分極性電極がセパレータを介して対向配置された基本セルを積層してなるキャパシタ素子を外装体にて覆われ、前記積層の方向に直交する周囲に封止部が設けられて封止された電気二重層キャパシタであって、前記外装体の内部を分割する絶縁性フィルムを備え、2個の前記キャパシタ素子が前記絶縁性フィルムを挟んで対向配置され、少なくとも前記封止部の連続した一部が、前記外装体と前記絶縁性フィルムとの接続にて形成され、かつ前記2個のキャパシタ素子の間に入り込んだことを特徴とする電気二重層キャパシタである。   In the present invention, a capacitor element formed by laminating a basic cell in which a pair of polarizable electrodes composed of a positive electrode and a negative electrode are arranged opposite to each other with a separator interposed therebetween is covered with an exterior body and sealed around the direction perpendicular to the direction of the lamination. An electric double layer capacitor provided with a stopper and sealed, including an insulating film that divides the interior of the exterior body, and the two capacitor elements are arranged opposite to each other with the insulating film interposed therebetween, An electric double layer capacitor, wherein at least a continuous part of the sealing portion is formed by connection between the exterior body and the insulating film and enters between the two capacitor elements. is there.

また、本発明は、前記キャパシタ素子の前記絶縁性フィルムに接する前記基本セルの面積が他の基本セルの面積より小さく、前記封止部の一部が前記面積の小さい箇所に入り込んだことを特徴とする電気二重層キャパシタである。   Further, the present invention is characterized in that the area of the basic cell in contact with the insulating film of the capacitor element is smaller than the area of the other basic cell, and a part of the sealing portion enters a portion having the small area. This is an electric double layer capacitor.

また、本発明は、前記絶縁性フィルムが熱可塑性樹脂であることを特徴とする電気二重層キャパシタである。   The present invention is the electric double layer capacitor, wherein the insulating film is a thermoplastic resin.

また、本発明は、前記絶縁性フィルムがポリプロピレン樹脂または酸変性ポリプロピレン樹脂であることを特徴とする電気二重層キャパシタである。   The present invention is the electric double layer capacitor, wherein the insulating film is a polypropylene resin or an acid-modified polypropylene resin.

本発明によれば、一つの外装体であるラミネートフィルム中にキャパシタ素子を複数個直列に接続して封止する場合でも、基本セルを積層して構成されるキャパシタ素子の一部の基本セルの絶縁性フィルムと接合する面積を小さくすることにより、ラミネートフィルムと絶縁性フィルムとの接続部の距離(シール幅)を充分に確保することができるため、薄型のままで電気二重層キャパシタの集電体の電極の面積を大きくでき、耐久性を維持した低抵抗の電気二重層キャパシタを提供することができる。   According to the present invention, even when a plurality of capacitor elements are connected in series and sealed in a laminate film as an exterior body, some basic cells of a capacitor element configured by stacking basic cells are used. By reducing the area to be bonded to the insulating film, the distance between the laminate film and the insulating film (seal width) can be secured sufficiently. It is possible to provide a low-resistance electric double layer capacitor that can increase the area of the body electrode and maintain durability.

以下、図面に基づいて本発明の好適な実施の形態について詳細に説明する。   Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

図1は、本発明に係る電気二重層キャパシタの説明図で、図1(a)は本発明に係る電気二重層キャパシタの上面図、図1(b)は本発明に係る電気二重層キャパシタの側面図、図1(c)は本発明に係る電気二重層キャパシタのB−B断面図、図1(d)は本発明に係る電気二重層キャパシタのA−A断面図である。   FIG. 1 is an explanatory diagram of an electric double layer capacitor according to the present invention, FIG. 1 (a) is a top view of the electric double layer capacitor according to the present invention, and FIG. 1 (b) is an electric double layer capacitor according to the present invention. FIG. 1C is a side view of the electric double layer capacitor according to the present invention, and FIG. 1D is a cross sectional view of the electric double layer capacitor according to the present invention taken along the line AA.

本発明の電気二重層キャパシタは、図1(c)に示すように、キャパシタ素子1、集電体リード部6、絶縁性フィルム2、電解液4、集電体リード部6と溶接部7によって電気的に接続されたリード端子5、外装体として主に使用されるラミネートフィルム3から構成される。また、この電気二重層キャパシタは、電解液4が含浸されたキャパシタ素子1をラミネートフィルム3で覆い、周囲に封止部を設けて密封する。これは、水分等の浸入を防ぐことにより、電気二重層キャパシタの耐久性を保っているためである。   As shown in FIG. 1 (c), the electric double layer capacitor of the present invention includes a capacitor element 1, a current collector lead portion 6, an insulating film 2, an electrolytic solution 4, a current collector lead portion 6 and a weld portion 7. It is comprised from the electrically connected lead terminal 5 and the laminate film 3 mainly used as an exterior body. Further, in this electric double layer capacitor, the capacitor element 1 impregnated with the electrolytic solution 4 is covered with a laminate film 3, and a sealing portion is provided around the capacitor element 1 for sealing. This is because the durability of the electric double layer capacitor is maintained by preventing intrusion of moisture and the like.

また、図1(c)に示すように、ラミネートフィルム3で外装されている電気二重層キャパシタ内部は、絶縁性フィルム2によって2分割され、分割されたそれぞれの空間部にキャパシタ素子1が配置される。キャパシタ素子1に電気的に接続された集電体リード部6は、リード端子5と溶接部7にて溶接され、電気的に接続される。   Further, as shown in FIG. 1 (c), the inside of the electric double layer capacitor that is covered with the laminate film 3 is divided into two parts by the insulating film 2, and the capacitor element 1 is arranged in each divided space part. The The current collector lead portion 6 electrically connected to the capacitor element 1 is welded and electrically connected to the lead terminal 5 and the welding portion 7.

電気二重層キャパシタの周囲は、リード端子5が延在する方向の周囲では、リード端子5と絶縁性フィルム2およびラミネートフィルム3は熱シール等によって好適に接続され、リード端子5が延在する方向と垂直の周囲では、絶縁性フィルム2とラミネートフィルム3は熱シール等によって好適に接続される。   In the periphery of the electric double layer capacitor, the lead terminal 5, the insulating film 2, and the laminate film 3 are suitably connected by heat sealing or the like in the direction in which the lead terminal 5 extends, and the lead terminal 5 extends. The insulating film 2 and the laminate film 3 are suitably connected by heat sealing or the like around the vertical direction.

上記のリード端子5が延在する方向と垂直の周囲では、図1(d)に示すように、ラミネートフィルム3が絶縁性フィルム2とキャパシタ素子1の間に入り込んで、ラミネートフィルム3と絶縁性フィルム2が接続して、封止部3aが形成される。   In the periphery perpendicular to the direction in which the lead terminal 5 extends, the laminate film 3 enters between the insulating film 2 and the capacitor element 1 as shown in FIG. The film 2 is connected to form the sealing portion 3a.

ここで、電気二重層キャパシタは、図1(d)に示すように、上下に2分割された空間部に、キャパシタ素子1が配置される際、絶縁性フィルム2に接する面の基本セル8(第1の基本セル)の面積を他の基本セル8(第2の基本セル)の面積よりも小さくするとよい。具体的な一例を示すと、第1の基本セルの大きさは10〜15×15〜20mm程度、第2の基本セルの大きさは15〜20×15〜20mm程度、ラミネートフィルム3の大きさは20〜30×25〜35mm程度がよい。   Here, as shown in FIG. 1 (d), the electric double layer capacitor has a basic cell 8 (on the surface in contact with the insulating film 2) when the capacitor element 1 is disposed in the space portion divided into two vertically. The area of the first basic cell may be smaller than the area of the other basic cell 8 (second basic cell). As a specific example, the size of the first basic cell is about 10-15 × 15-20 mm, the size of the second basic cell is about 15-20 × 15-20 mm, the size of the laminate film 3 Is preferably about 20 to 30 × 25 to 35 mm.

上記のように、絶縁性フィルム2に接続する基本セルの面積を他の基本セルの面積より小さくし、その封止部3aをそこに入り込ませることで、ラミネートフィルム3と絶縁性フィルム2が好適に接続され、キャパシタ素子1が変形させることがなくなる。   As described above, the laminate film 3 and the insulating film 2 are suitable by making the area of the basic cell connected to the insulating film 2 smaller than the area of the other basic cells and allowing the sealing portion 3a to enter there. The capacitor element 1 is not deformed.

絶縁性フィルム2とラミネートフィルム3との接続面積を大きくするために、ラミネートフィルム3を入り込ませることで、絶縁性フィルム2とラミネートフィルム3の接着強度を大きくできる。封止部3aの入り込みの長さは図3(c)のシール幅12程度がよく、逆に、このシール幅12以上だと上記の第1の基本セル8の面積が減少するので、電気二重層キャパシタの低抵抗化の効果が得られない。   In order to increase the connection area between the insulating film 2 and the laminate film 3, the adhesive strength between the insulating film 2 and the laminate film 3 can be increased by inserting the laminate film 3. The sealing portion 3a has an intrusion length of about the seal width 12 in FIG. 3C. Conversely, if the seal width is 12 or more, the area of the first basic cell 8 is reduced. The effect of lowering the resistance of the multilayer capacitor cannot be obtained.

なお、これらの電気二重層キャパシタの周囲の接続には、熱シール等によって好適に接続される。また、リード端子5と絶縁性フィルム2およびラミネートフィルム3の接続には、接着剤を用いて接続したり、カシメ等の方法で接続してもよい。   In addition, the connection around these electric double layer capacitors is preferably connected by heat sealing or the like. Further, the lead terminal 5, the insulating film 2 and the laminate film 3 may be connected using an adhesive or may be connected by a method such as caulking.

これにより、上記他の基本セル8の面積を大きくすることができるため、低抵抗の電気二重層キャパシタを提供することも可能となる。   Thereby, since the area of the other basic cell 8 can be increased, a low resistance electric double layer capacitor can be provided.

ここで、本発明の電気二重層コンデンサに用いる材料について説明する。   Here, materials used for the electric double layer capacitor of the present invention will be described.

分極性電極は主として炭素材料で構成されており、炭素材料にはフェノール樹脂系活性炭、やしがら系活性炭、石油コークス系活性炭やポリアセンなどを用いるとよい。また、活性炭としては、大容量で低内部抵抗の電気二重層キャパシタが得られるように、粉末の場合は平均粒径が20μm以下で、比表面積が1000〜3000m2/gの活性炭を使用するのが好ましい。 The polarizable electrode is mainly composed of a carbon material. As the carbon material, phenol resin-based activated carbon, coconut-based activated carbon, petroleum coke-based activated carbon, polyacene, or the like may be used. As the activated carbon, activated carbon having an average particle size of 20 μm or less and a specific surface area of 1000 to 3000 m 2 / g is used in the case of powder so that an electric double layer capacitor having a large capacity and a low internal resistance can be obtained. Is preferred.

分極性電極には、必要に応じて導電助剤が添加される。導電助剤としては、黒鉛、カーボンブラック、気相成長カーボンやカーボンナノチューブなどが好ましく、特に、黒鉛、カーボンブラックが好ましい。また、場合によっては、分極性電極にバインダが添加されるが、このバインダには有機溶媒系電解液に対して耐薬品性を有し、キャパシタ特性に影響を及ぼさないものを選択すればよく、一般にはポリフッ化ビニリデンやポリテトラフルオロエチレンなどを用いるのが好ましい。   If necessary, a conductive additive is added to the polarizable electrode. As the conductive aid, graphite, carbon black, vapor-grown carbon, carbon nanotube, and the like are preferable, and graphite and carbon black are particularly preferable. In some cases, a binder is added to the polarizable electrode, and this binder may be selected from those having chemical resistance to the organic solvent electrolyte and not affecting the capacitor characteristics. In general, it is preferable to use polyvinylidene fluoride or polytetrafluoroethylene.

セパレータには、例えば、電気二重層キャパシタ用として、レーヨン系抄紙、ガラス繊維混抄紙やポリプロピレン不織布などが使用できる。   For the separator, for example, rayon papermaking, glass fiber mixed paper, polypropylene nonwoven fabric, etc. can be used for electric double layer capacitors.

集電体用の材料は、使用する電気二重層キャパシタの特性に応じて適宜選択すればよく、アルミニウム、ステンレス、銅やニッケル等が使用されるが、特にアルミニウムが好ましい。集電体に電極層を形成する方法は従来の方法でよく、電極層に用いる部材を溶媒に分散させてスラリとし、低抵抗とするためにそのスラリを表面エッチング処理として集電体に塗工してもよい。塗工法としては一般に、メタルマスク印刷法、静電塗装法、ディップコート法、スプレーコート法、ロールコート法、ドクターブレード法、グラビアコート法、スクリーン印刷法等が使用されている。その後、必要に応じて、平板プレス、カレンダーロール等により圧延処理を行ってもよい。また、塗工法以外にも押し出し法によりシート状の電極を形成し、次いで集電体に導電性接着剤を用いて一体化する方法でもよい。   The material for the current collector may be appropriately selected according to the characteristics of the electric double layer capacitor to be used, and aluminum, stainless steel, copper, nickel or the like is used, and aluminum is particularly preferable. The method for forming the electrode layer on the current collector may be a conventional method. The member used for the electrode layer is dispersed in a solvent to form a slurry, and the slurry is applied to the current collector as a surface etching treatment in order to reduce resistance. May be. Generally, a metal mask printing method, an electrostatic coating method, a dip coating method, a spray coating method, a roll coating method, a doctor blade method, a gravure coating method, a screen printing method and the like are used as the coating method. Thereafter, rolling may be performed by a flat plate press, a calender roll, or the like, if necessary. In addition to the coating method, a sheet-like electrode may be formed by an extrusion method, and then integrated with the current collector using a conductive adhesive.

電解液としては、電気化学的に安定な電解質を極性有機溶媒に溶解させたものを適宜使用すればよい。電解質としては、(C254+や(C494+、(C254+などの第4級オニウムカチオンと、BF4 -やPF6 -、ClO4 -などのアニオンとからなる塩が好ましい。有機溶媒としては、プロピレンカーボネート、ブチレンカーボネート、ジエチルカーボネートなどのカーボネート類、γ−ブチロラクトンなどのラクトン類やスルホランなどが好ましい。これらの有機溶媒は、単独でなく、2種以上併用してもよい。 What is necessary is just to use suitably what melt | dissolved the electrochemically stable electrolyte in the polar organic solvent as electrolyte solution. Examples of the electrolyte include quaternary onium cations such as (C 2 H 5 ) 4 N + , (C 4 H 9 ) 4 N + , (C 2 H 5 ) 4 P + , BF 4 and PF 6 , ClO 4 - anions comprising a salt such as preferred. As the organic solvent, carbonates such as propylene carbonate, butylene carbonate and diethyl carbonate, lactones such as γ-butyrolactone, sulfolane and the like are preferable. These organic solvents may be used alone or in combination of two or more.

熱可塑性絶縁性フィルムには、ポリエチレンやポリプロピレン、エチレン−メタクリル酸共重合体などに代表される熱可塑性樹脂を用いればよい。   A thermoplastic resin typified by polyethylene, polypropylene, ethylene-methacrylic acid copolymer, etc. may be used for the thermoplastic insulating film.

ラミネートフィルムには、金属箔とポリオレフィン系フィルムを貼り合わせたラミネートフィルムを用いればよい。   As the laminate film, a laminate film in which a metal foil and a polyolefin film are bonded together may be used.

以下に、実施例を挙げて、本発明の説明をする。   Hereinafter, the present invention will be described with reference to examples.

(実施例)
比表面積2000m2/gのやしがら系活性炭とカーボンブラックとポリフッ化ビニリデンを重量比8:1:1で混合したものに溶媒を加えスラリを作製した。このスラリを表面エッチング処理した13×16mm、30μm厚のアルミニウム箔の両面にドクターブレード法にて電極面積が12.5×15.5mm2になるように塗布し分極性電極を作製した。分極性電極の分極性電極層はアルミニウム集電体に厚みが30μm厚になるように塗工した。つまり、集電体リード部となる未塗工部を除いた電極面積が12.5×15.5mm2になるように正負極電極を製作した。
(Example)
A slurry was prepared by adding a solvent to a mixture of coconut shell activated carbon having a specific surface area of 2000 m 2 / g, carbon black, and polyvinylidene fluoride in a weight ratio of 8: 1: 1. The slurry was applied to both surfaces of a 13 × 16 mm, 30 μm thick aluminum foil surface-etched by a doctor blade method so that the electrode area would be 12.5 × 15.5 mm 2 to produce a polarizable electrode. The polarizable electrode layer of the polarizable electrode was coated on an aluminum current collector to a thickness of 30 μm. That is, the positive and negative electrodes were manufactured so that the electrode area excluding the uncoated portion that would be the current collector lead portion would be 12.5 × 15.5 mm 2 .

次に、12.5×15.5mmの正極と負極の各電極を、13×16mmで25μm厚のレーヨン系セパレータで挟んで第1の基本セルを作製し、2個積層した。また、15.5×15.5mmの正極と負極の各電極を、16×16mmで25μm厚のレーヨン系セパレータで挟んで第2の基本セルを作製し、6個積層した。図1(d)に示すように、この第1の基本セル2層と第2の基本セル6層を組み合わせて(合計の基本セルは8層)、キャパシタ素子を2個作製した。   Next, a 12.5 × 15.5 mm positive electrode and a negative electrode were sandwiched between 13 × 16 mm and 25 μm thick rayon separators to form a first basic cell, and two layers were stacked. A second basic cell was prepared by sandwiching each 15.5 × 15.5 mm positive electrode and negative electrode between 16 × 16 mm and 25 μm thick rayon separators, and six were stacked. As shown in FIG. 1 (d), two capacitor elements were fabricated by combining the first basic cell 2 layers and the second basic cell 6 layers (the total number of basic cells is 8 layers).

また、図1(d)に示すように、25×27mmで、115μm厚のナイロンとアルミニウム箔およびポリプロピレンの三層構造からなるラミネートフィルムを2枚用意し、中央部に、深さ1.0mmの凹部ができるように、エンボス加工し、この2枚のラミネートフィルムを鏡に映したように対向配置し、その2枚のラミネートフィルムの間に100μm厚の酸変性ポリプロピレンフィルムを挟んで、ラミネートフィルム2枚と酸変性ポリプロピレンフィルムを組み合わせ、隣り合わない対向する2つの端を折り畳んで封止部に2mmの幅で配置し、この2mmの幅を熱シール機で150℃、3秒間融着した。   Also, as shown in FIG. 1 (d), two laminate films of a three-layer structure of 25 × 27 mm, 115 μm-thick nylon, aluminum foil, and polypropylene are prepared, and the center portion has a depth of 1.0 mm. Embossed so as to form a recess, the two laminated films are placed opposite to each other as reflected in a mirror, and an acid-modified polypropylene film having a thickness of 100 μm is sandwiched between the two laminated films. A sheet and an acid-modified polypropylene film were combined, and two opposite ends that were not adjacent to each other were folded and placed in a sealed portion with a width of 2 mm, and the width of 2 mm was fused at 150 ° C. for 3 seconds with a heat sealer.

このラミネートフィルムと酸変性ポリプロピレンフィルム間の2箇所の空間部に上記キャパシタ素子をそれぞれ挿入し、25×27mm角のラミネートフィルムの隣り合わない対向する他の2つの端のうち、1つの端から2.5mmの位置に窪みを付けたラミネートフィルム形状とし、この端から2mmの幅を熱シール機で150℃、3秒間融着した。   The capacitor element is inserted into each of two spaces between the laminate film and the acid-modified polypropylene film, and the other two ends of the 25 × 27 mm square laminate film that are not adjacent to each other are separated from one end to the second end. A laminate film shape having a depression at a position of 5 mm was formed, and a width of 2 mm from this end was fused at 150 ° C. for 3 seconds with a heat sealer.

最後に、残った未融着のラミネートフィルムの端に、各セルにテトラメチルアンモニウムテトラフルオロボーレートとプロピレンカーボネートの混合溶媒からなる電解液を注入し、−98MPaの減圧下にて下部から2mmの幅で熱シールを行った。その後、2個のキャパシタ素子を、正極同士または負極同士に電気的に接続された集電体リード部を0.1mm厚のリード端子と共に超音波溶接することで、直列接合型電気二重層キャパシタを作製した。この時のキャパシタ製品の外形寸法は、外装面積25×18mm2で、厚みは2.3mmとした。 Finally, an electrolyte solution composed of a mixed solvent of tetramethylammonium tetrafluoroborate and propylene carbonate is injected into each cell at the end of the remaining unfused laminate film, and a width of 2 mm from the bottom under reduced pressure of -98 MPa. And heat sealed. Thereafter, two capacitor elements are ultrasonically welded together with a lead terminal having a thickness of 0.1 mm to a current collector lead portion electrically connected to each other between the positive electrodes or the negative electrodes. Produced. The external dimensions of the capacitor product at this time were an exterior area of 25 × 18 mm 2 and a thickness of 2.3 mm.

このキャパシタ製品の1kHz時のESR(等価直列抵抗)を5個測定したところ、その平均値は95mΩであった。   When five ESR (equivalent series resistance) at 1 kHz of this capacitor product were measured, the average value was 95 mΩ.

(比較例)
実施例と同様に、13×16mm、30μm厚のアルミ箔の表面に、比表面積2000m2/gのやしがら系活性炭とカーボンブラックとポリフッ化ビニリデンを重量比8:1:1で混合したものに溶媒を加えスラリを30μm厚で塗布し、第1の基本セルを8個積層したキャパシタ素子に、これらの正極同士または負極同士に電気的に接続された集電体リード部を0.1mm厚のリード端子と共に超音波溶接し、並列積層のキャパシタ素子を2個作製した。
(Comparative example)
In the same manner as in the example, a 13 × 16 mm, 30 μm thick aluminum foil surface mixed with coconut palm activated carbon having a specific surface area of 2000 m 2 / g, carbon black, and polyvinylidene fluoride in a weight ratio of 8: 1: 1. To the capacitor element in which the solvent was added to the slurry and the slurry was applied to a thickness of 30 μm, and the eight first basic cells were stacked, the current collector lead portion electrically connected to these positive electrodes or negative electrodes was 0.1 mm thick The two lead capacitors were ultrasonically welded to produce two parallel laminated capacitor elements.

また、25×18mmで、115μm厚のラミネートフィルムを2枚用意し、中央部に、深さ1.0mmの凹部ができるように、エンボス加工することで、25×18mm角のラミネートフィルムの外周の各端部から2.0mmの位置にコの字状の窪みを付けたラミネートフィルムを作製した。   Also, two 115 μm thick laminate films of 25 × 18 mm were prepared, and embossed so that a concave portion with a depth of 1.0 mm was formed at the center, so that the outer periphery of the 25 × 18 mm square laminate film was A laminate film having a U-shaped depression at a position 2.0 mm from each end was produced.

上記ラミネートフィルムを2個の用意し、この2枚のラミネートフィルムを鏡に映したように対向配置し、その2枚のラミネートフィルムの間に100μm厚の酸変性ポリプロピレンフィルムを挟んで、ラミネートフィルム2枚と酸変性ポリプロピレンフィルムを組み合わせ、隣り合わない対向する2つの端から2mmの幅を熱シール機で150℃、3秒間融着した。このラミネートフィルムと酸変性ポリプロピレンフィルム間の2箇所の空間部に上記キャパシタ素子をそれぞれ挿入し、ラミネートフィルムの他端部の上下方向から2mmの幅を熱シール機で融着した。これ以降は、実施例と同様の工程にて電気二重層キャパシタを作製した。この時のキャパシタ製品の外形寸法は、実施例と同じの外装面積25×18mm2で、厚みは2.3mmとした。 Two laminate films are prepared, and the two laminate films are arranged to face each other as reflected in a mirror, and an acid-modified polypropylene film having a thickness of 100 μm is sandwiched between the two laminate films. The sheet and the acid-modified polypropylene film were combined, and a width of 2 mm from two opposite ends not adjacent to each other was fused at 150 ° C. for 3 seconds with a heat sealing machine. The capacitor elements were respectively inserted into two spaces between the laminate film and the acid-modified polypropylene film, and a width of 2 mm from the vertical direction of the other end of the laminate film was fused with a heat sealer. Thereafter, an electric double layer capacitor was manufactured in the same process as in the example. The external dimensions of the capacitor product at this time were the same exterior area of 25 × 18 mm 2 as in the example, and the thickness was 2.3 mm.

このキャパシタ製品の1kHz時のESRを5個測定したところ、その平均値は115mΩであった。   When five ESRs at 1 kHz of this capacitor product were measured, the average value was 115 mΩ.

以上のことにより、比較例と同じ外形寸法の本実施例の電気二重層キャパシタのESRを比較した結果を表1に示す。   Table 1 shows the result of comparing the ESR of the electric double layer capacitor of this example having the same external dimensions as the comparative example.

Figure 2010003773
Figure 2010003773

表1に示すように、ESRの平均値は、比較例が115mΩであったのに対し、実施例は95mΩであり、実施例の平均値は、比較例の平均値と比べて82.6%となり、17.4%もの低抵抗化となることが分かった。   As shown in Table 1, the average value of ESR was 115 mΩ in the comparative example, whereas it was 95 mΩ in the example. The average value of the example was 82.6% compared with the average value of the comparative example. It was found that the resistance was reduced by 17.4%.

これにより、本発明によれば、薄型の電気二重層キャパシタで、耐久性を維持した低抵抗の電気二重層キャパシタを提供することを可能とする。   As a result, according to the present invention, it is possible to provide a low-resistance electric double layer capacitor that maintains durability with a thin electric double layer capacitor.

本発明に係る電気二重層キャパシタの説明図。図1(a)は、本発明に係る電気二重層キャパシタの上面図。図1(b)は本発明に係る電気二重層キャパシタの側面図。図1(c)は本発明に係る電気二重層キャパシタのB−B断面図。図1(d)は本発明に係る電気二重層キャパシタのA−A断面図。Explanatory drawing of the electric double layer capacitor which concerns on this invention. FIG. 1A is a top view of an electric double layer capacitor according to the present invention. FIG. 1B is a side view of the electric double layer capacitor according to the present invention. FIG.1 (c) is BB sectional drawing of the electric double layer capacitor based on this invention. FIG.1 (d) is AA sectional drawing of the electric double layer capacitor based on this invention. キャパシタ素子の説明図。Explanatory drawing of a capacitor element. 電気二重層キャパシタの説明図。図3(a)は比較例の電気二重層キャパシタの上面図。図3(b)は比較例の電気二重層キャパシタの側面図。図3(c)は比較例の電気二重層キャパシタのC−C断面図。図3(d)は比較例の電気二重層キャパシタ構造においてラミネートフィルムと絶縁性フィルムとの接合距離を短くした場合のC−C断面図。Explanatory drawing of an electric double layer capacitor. FIG. 3A is a top view of the electric double layer capacitor of the comparative example. FIG. 3B is a side view of the electric double layer capacitor of the comparative example. FIG.3 (c) is CC sectional drawing of the electric double layer capacitor of a comparative example. FIG.3 (d) is CC sectional drawing at the time of shortening the joining distance of a laminate film and an insulating film in the electric double layer capacitor structure of a comparative example.

符号の説明Explanation of symbols

1 キャパシタ素子
2 絶縁性フィルム
3 ラミネートフィルム
3a 封止部
4 電解液
5 リード端子
6,6a,6b 集電体リード部
7 溶接部
8 基本セル
9 分極性電極
10 セパレータ
11 集電体
12 シール幅
DESCRIPTION OF SYMBOLS 1 Capacitor element 2 Insulating film 3 Laminate film 3a Sealing part 4 Electrolytic solution 5 Lead terminal 6, 6a, 6b Current collector lead part
7 Welded part 8 Basic cell 9 Polarized electrode 10 Separator 11 Current collector 12 Seal width

Claims (4)

正極および負極からなる一対の分極性電極がセパレータを介して対向配置された基本セルを積層してなるキャパシタ素子が外装体にて覆われ、前記積層の方向に直交する周囲に封止部が設けられて封止された電気二重層キャパシタであって、
前記外装体の内部を分割する絶縁性フィルムを備え、
2個の前記キャパシタ素子が前記絶縁性フィルムを挟んで対向配置され、
少なくとも前記封止部の連続した一部が、前記外装体と前記絶縁性フィルムとの接続にて形成され、かつ前記2個のキャパシタ素子の間に入り込んだことを特徴とする電気二重層キャパシタ。
A capacitor element formed by laminating a basic cell in which a pair of polarizable electrodes composed of a positive electrode and a negative electrode are arranged opposite to each other with a separator interposed therebetween is covered with an exterior body, and a sealing portion is provided around the direction perpendicular to the direction of the lamination. A sealed electric double layer capacitor,
Comprising an insulating film that divides the interior of the exterior body;
Two capacitor elements are arranged opposite to each other with the insulating film interposed therebetween,
An electric double layer capacitor, wherein at least a continuous part of the sealing portion is formed by connection between the exterior body and the insulating film and enters between the two capacitor elements.
前記キャパシタ素子の前記絶縁性フィルムに接する前記基本セルの面積が他の基本セルの面積より小さく、前記封止部の一部が前記面積の小さい箇所に入り込んだことを特徴とする請求項1記載の電気二重層キャパシタ。   2. The area of the basic cell in contact with the insulating film of the capacitor element is smaller than the area of another basic cell, and a part of the sealing portion enters a portion having the small area. Electric double layer capacitor. 前記絶縁性フィルムが熱可塑性樹脂であることを特徴とする請求項1又は2記載の電気二重層キャパシタ。   The electric double layer capacitor according to claim 1, wherein the insulating film is a thermoplastic resin. 前記絶縁性フィルムがポリプロピレン樹脂または酸変性ポリプロピレン樹脂であることを特徴とする請求項1又は2記載の電気二重層キャパシタ。   The electric double layer capacitor according to claim 1, wherein the insulating film is a polypropylene resin or an acid-modified polypropylene resin.
JP2008159832A 2008-06-19 2008-06-19 Electric double layer capacitor Pending JP2010003773A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013115411A (en) * 2011-12-01 2013-06-10 Rohm Co Ltd Laminated energy device and manufacturing method therefor
KR20220097086A (en) * 2020-12-31 2022-07-07 현대자동차주식회사 Energy storage device

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013115411A (en) * 2011-12-01 2013-06-10 Rohm Co Ltd Laminated energy device and manufacturing method therefor
KR20220097086A (en) * 2020-12-31 2022-07-07 현대자동차주식회사 Energy storage device
KR102575732B1 (en) * 2020-12-31 2023-09-08 현대자동차주식회사 Energy storage device

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