JP2010239085A - Electric double layer capacitor - Google Patents

Electric double layer capacitor Download PDF

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JP2010239085A
JP2010239085A JP2009088284A JP2009088284A JP2010239085A JP 2010239085 A JP2010239085 A JP 2010239085A JP 2009088284 A JP2009088284 A JP 2009088284A JP 2009088284 A JP2009088284 A JP 2009088284A JP 2010239085 A JP2010239085 A JP 2010239085A
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double layer
electric double
layer capacitor
solid base
positive electrode
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Satoru Tsumeda
覚 爪田
Shuichi Ishimoto
修一 石本
Hiroshi Komatsu
普司 駒津
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Nippon Chemi Con 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
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    • Y02E60/13Energy storage using capacitors

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric double layer capacitor that is suppressed in variation in capacity and variation in internal resistance even when used at high temperature to show long-life characteristics. <P>SOLUTION: The electric double layer capacitor is constituted by storing, in an encapsulating case, a capacitive element including a positive electrode and negative electrode having polarization properties, and a separator disposed therebetween and holding a nonaqueous electrolyte, the encapsulating case containing a solid base such as amorphous silica alumina. The solid base adsorbs a proton generated on a positive electrode surface which is not opposed to the negative electrode to suppress acidification and resolution of the electrolyte, thereby obtaining the electric double layer capacitor that is prevented from deteriorating in capacity and from increasing in internal resistance even when used at high temperature of >60°C to show long-life characteristics. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

本発明は、高温使用下においても容量及び内部抵抗の変化が抑制された、寿命特性の良好な電気二重層キャパシタに関する。   The present invention relates to an electric double layer capacitor having excellent life characteristics in which changes in capacitance and internal resistance are suppressed even under high temperature use.

電気二重層キャパシタは、従来から電子機器におけるメモリバックアップ、各種アクチュエータの駆動等のために広く使用されており、近年では、電気自動車やハイブリッド自動車などの低公害車におけるモーター駆動電源として、高エネルギー密度及び高出力密度を有する電気二重層キャパシタの開発が進められている。   Electric double layer capacitors have been widely used for memory backup in electronic devices, driving various actuators, etc., and in recent years, they have high energy density as motor drive power sources for low-pollution vehicles such as electric vehicles and hybrid vehicles. In addition, electric double layer capacitors having high power density are being developed.

電気二重層キャパシタは、活性炭などの分極性電極を正負極とし、電極表面と電解液との界面に生じる電気二重層を静電容量として利用しており、出力密度が高く、急速充放電が可能であり、充放電を繰り返しても容量劣化が比較的少ないという特徴を有している。電気二重層キャパシタでは、充放電に伴って電解質イオンが電解液内を移動して電極界面に吸脱着するだけであり、電池のような電気化学反応を伴わないためである。   The electric double layer capacitor uses polarizable electrodes such as activated carbon as positive and negative electrodes, and uses the electric double layer generated at the interface between the electrode surface and the electrolyte as the capacitance, which has a high output density and enables rapid charge and discharge. Thus, the capacity deterioration is relatively small even when charging and discharging are repeated. This is because in an electric double layer capacitor, electrolyte ions move only in the electrolytic solution along with charging / discharging and are adsorbed / desorbed to / from the electrode interface, and do not involve an electrochemical reaction as in a battery.

電気二重層キャパシタの構造としては、巻回型と積層型とが一般的である。巻回型キャパシタは、帯状の正極と負極とをこれらの間に挟んだセパレータと共に円筒状の巻芯の周囲に巻きつけて巻回素子を得、この素子に電解液を含浸させた後、有底筒状の外装ケース内に収容し、封口体により密封することにより構成している。また、積層型キャパシタは、複数枚の正極と負極とをセパレータを挟んで交互に積層して絶縁性の素子止めテープでまとめて1つの積層素子を得、この積層素子をさらに複数個積層させて絶縁性のテープでまとめ、この素子に電解液を含浸させた後、有底筒状の外装ケース内に収容し、封口体により密封することにより構成している。   As a structure of the electric double layer capacitor, a winding type and a multilayer type are generally used. A wound capacitor is obtained by winding a strip-shaped positive electrode and a negative electrode around a cylindrical core together with a separator sandwiched between them to obtain a wound element, impregnating the element with an electrolyte, It is configured by being housed in a bottom cylindrical outer case and sealed with a sealing body. In addition, a multilayer capacitor is formed by alternately laminating a plurality of positive electrodes and negative electrodes with a separator interposed therebetween, and collecting them with an insulating element stop tape to obtain one multilayer element. It is configured by packing with an insulating tape, impregnating this element with an electrolytic solution, and then housing it in a bottomed cylindrical outer case and sealing it with a sealing body.

そして、電気二重層キャパシタには、水系電解液を用いたキャパシタと、非水系電解液(有機電解液)を用いたキャパシタとが存在する。電気二重層キャパシタの作動電圧は主に電解液の電気分解電圧によって決定されるため、水系電解液を用いたキャパシタは非水系電解液を用いたキャパシタに比較して作動電圧の点で不利である。作動電圧を高めることはエネルギー密度の向上につながるため、高エネルギー密度が要求される用途には、プロピレンカーボネート、エチレンカーボネートなどの有機溶媒にトリエチルメチルアンモニウム(TEMA)などの4級アンモニウム塩カチオンとテトラフルオロボレート(BF)などのアニオンからなる電解質を溶解させた非水系電解液を用いる電気二重層キャパシタが使用されている。 The electric double layer capacitor includes a capacitor using an aqueous electrolyte and a capacitor using a non-aqueous electrolyte (organic electrolyte). Since the operating voltage of an electric double layer capacitor is mainly determined by the electrolytic voltage of the electrolyte, a capacitor using an aqueous electrolyte is disadvantageous in terms of operating voltage compared to a capacitor using a non-aqueous electrolyte. . Increasing the operating voltage leads to an improvement in energy density. For applications requiring high energy density, an organic solvent such as propylene carbonate or ethylene carbonate and a quaternary ammonium salt cation such as triethylmethylammonium (TEMA) and tetra An electric double layer capacitor using a nonaqueous electrolytic solution in which an electrolyte composed of an anion such as fluoroborate (BF 4 ) is dissolved is used.

ところが、このような非水系電解液を用いた電気二重層キャパシタを60℃以上の高温下で使用すると、電解液の分解反応が生じ、キャパシタの容量が低下し、内部抵抗が増加するという問題が生じていた。   However, when such an electric double layer capacitor using a non-aqueous electrolyte is used at a high temperature of 60 ° C. or higher, a decomposition reaction of the electrolyte occurs, the capacity of the capacitor decreases, and the internal resistance increases. It was happening.

このような問題に対し、電解液の分解を抑制する添加物を加える検討がされており、例えば特許文献1(特開2004−146610号公報)は、電解液にジフェニルを添加する方法を開示している。   In order to solve such problems, studies have been made to add an additive that suppresses the decomposition of the electrolytic solution. For example, Patent Document 1 (Japanese Patent Laid-Open No. 2004-146610) discloses a method of adding diphenyl to the electrolytic solution. ing.

特開2004−146610号公報JP 2004-146610 A

特許文献1におけるジフェニルの添加により、分解ガスの発生が抑制されるものの、60℃を超える高温下でのキャパシタの使用では、このような添加物を電解液に添加するような方法では、容量の低下、内部抵抗の増大に対する抑制効果が十分でない。   Although the generation of decomposition gas is suppressed by the addition of diphenyl in Patent Document 1, in the use of a capacitor at a high temperature exceeding 60 ° C., in a method in which such an additive is added to the electrolytic solution, the capacity is reduced. The effect of suppressing the increase in internal resistance is not sufficient.

また、発明者が、70℃、2.5V負荷試験において安全弁の開弁、容量の低下、内部抵抗の増大が認められた巻回型の電気二重層キャパシタを分解してみたところ、特に巻芯部近傍において、不溶成分が素子に付着して顕著に黒色化した部分が認められ、この部分の電解液(のpH)が酸性化していた(本出願の出願時には未公開である、出願人による特願2008−251869号の段落0055参照)。この不溶成分の堆積、pHの酸性化も、電気二重層キャパシタの容量の低下、内部抵抗の増大の原因になっていると思われる。   In addition, when the inventor disassembled a wound type electric double layer capacitor in which a safety valve opened, a decrease in capacity, and an increase in internal resistance were recognized in a 70 ° C., 2.5 V load test, In the vicinity of the part, a part where the insoluble component adhered to the device was noticeably blackened, and the electrolytic solution (pH) of this part was acidified (by the applicant, unpublished at the time of filing this application) (See paragraph 0055 of Japanese Patent Application No. 2008-251869). The accumulation of insoluble components and the acidification of pH are thought to cause a decrease in the capacitance of the electric double layer capacitor and an increase in internal resistance.

そこで、本発明の課題は、60℃を超える高温下で使用しても容量及び内部抵抗の変化が抑制され、長寿命特性を示す電気二重層キャパシタを提供することである。   Accordingly, an object of the present invention is to provide an electric double layer capacitor that exhibits a long life characteristic by suppressing changes in capacitance and internal resistance even when used at a high temperature exceeding 60 ° C.

発明者は、上述のような不溶成分が付着した巻回型電気二重層キャパシタを詳細に調べたところ、巻芯部分の正極の巻芯の周面に面した側が負極と対向しておらず、この負極と対向していない正極上で素子に含まれる水分の電気化学分解で発生したプロトンにより電解液が酸性化し、またこのプロトンが触媒となってプロピレンカーボネート等の有機溶媒が分解し、分解物が不溶成分となって素子に付着していることがわかった。また、積層型の電気二重層キャパシタにおいても、高温負荷試験において、絶縁性の素子止めテープを介さずに負極と接触していた正極側のセパレータには不溶成分が付着していないのに対し、素子止めテープを介して負極と接触していた正極側のセパレータ部分には不溶成分が付着しており、巻回型の電気二重層キャパシタにおける巻芯部分の現象と同様の現象が生じていることがわかった。   The inventor examined the wound type electric double layer capacitor to which the insoluble component as described above was attached in detail, and the side facing the peripheral surface of the positive electrode core of the core part did not face the negative electrode, Electrolyte is acidified by protons generated by electrochemical decomposition of moisture contained in the element on the positive electrode not facing the negative electrode, and this proton serves as a catalyst to decompose organic solvents such as propylene carbonate, resulting in decomposition products. It was found that became an insoluble component and adhered to the element. In addition, in the multilayer electric double layer capacitor, in the high temperature load test, the insoluble component is not attached to the separator on the positive electrode side that is in contact with the negative electrode without using the insulating element stopper tape, Insoluble components adhere to the separator on the positive electrode side that was in contact with the negative electrode via the element stop tape, and a phenomenon similar to the phenomenon of the core part in the wound type electric double layer capacitor has occurred. I understood.

そして、発明者は、電気二重層キャパシタの外装ケース内に固体塩基を含ませることによりこの現象が抑制され、高温負荷試験においても、素子に対する不溶成分の付着が認められず、電気二重層キャパシタの容量の低下及び内部抵抗の上昇が大幅に抑制されることを発見し、発明を完成させた。   Then, the inventor suppresses this phenomenon by including a solid base in the outer case of the electric double layer capacitor, and in the high temperature load test, no adhesion of insoluble components to the element is observed, and the electric double layer capacitor The inventors discovered that the decrease in capacity and the increase in internal resistance were greatly suppressed, and completed the invention.

したがって、本発明の電気二重層キャパシタは、分極性を有する正極及び負極とこれらの間に配置された非水系電解液を保持したセパレータとを有するキャパシタ素子が外装ケース内に収容されている電気二重層キャパシタであって、上記外装ケース内に固体塩基が含まれていることを特徴とする。固体塩基は、外装ケース内のどの部位に存在させても良い。電気二重層キャパシタの使用過程において、固体塩基が重力の作用により外装ケース内で下方に移動するが、負極と対向していない正極面上で発生したプロトンを含む電解液も下方に移動し、固体塩基によりプロトンが吸着され、電解液の酸性化とプロピレンカーボネート等の有機溶媒の分解が抑制される。   Therefore, the electric double layer capacitor of the present invention is an electric double layer capacitor in which a capacitor element having a polarizable positive electrode and a negative electrode and a separator holding a non-aqueous electrolyte disposed therebetween is accommodated in an outer case. The multilayer capacitor is characterized in that a solid base is contained in the outer case. The solid base may be present at any site in the outer case. In the process of using the electric double layer capacitor, the solid base moves downward in the outer case by the action of gravity, but the electrolyte containing protons generated on the positive electrode surface not facing the negative electrode also moves downward, Protons are adsorbed by the base and acidification of the electrolyte and decomposition of organic solvents such as propylene carbonate are suppressed.

本発明において、電気二重層キャパシタの構造には限定が無いが、上記電気二重層キャパシタが巻回型、すなわち、帯状の正極と負極とをこれらの間に挟んだセパレータと共に円筒状の巻芯の周囲に正極が巻芯の周面に面するように巻きつけることによって巻回素子を得、該巻回素子に非水系電解液を含浸させた後、有底筒状の外装ケース内に収容することにより構成されたものである場合には、上記固体塩基が上記外装ケース内の底部に設けられていると、プロトンを含む電解液が下方に移動して、固体塩基によりプロトンが吸着され、電解液の酸性化とプロピレンカーボネート等の有機溶媒の分解が抑制されるので好ましい。なお、正極と負極とセパレータとを円筒状の巻芯の周囲に負極が巻芯の周面に面するように巻きつけても、対向する負極を持たない正極が存在する場所があれば、固体塩基による本発明の効果が得られる。   In the present invention, the structure of the electric double layer capacitor is not limited, but the electric double layer capacitor is wound type, that is, a cylindrical core with a separator sandwiching a belt-like positive electrode and negative electrode between them. A winding element is obtained by winding the positive electrode so as to face the peripheral surface of the winding core, and the winding element is impregnated with a non-aqueous electrolyte solution and then accommodated in a bottomed cylindrical outer case. If the solid base is provided at the bottom of the outer case, the electrolyte solution containing protons moves downward, and the protons are adsorbed by the solid base and electrolyzed. This is preferable because acidification of the liquid and decomposition of an organic solvent such as propylene carbonate are suppressed. In addition, even if the positive electrode, the negative electrode, and the separator are wound around the cylindrical core so that the negative electrode faces the circumferential surface of the core, if there is a place where there is a positive electrode that does not have an opposing negative electrode, a solid The effect of the present invention by the base is obtained.

また、上記巻回型キャパシタでは、固体塩基を円筒状の巻芯内に収容しておくと、正極の巻芯の周面に面する側で発生したプロトンが効率的に吸着されるため好ましい。   In the wound capacitor, it is preferable to store the solid base in a cylindrical core because protons generated on the side facing the peripheral surface of the positive electrode core are efficiently adsorbed.

上記電気二重層キャパシタが積層型、すなわち、複数枚の正極と負極とをセパレータを挟んで交互に積層して絶縁性の素子止めテープでまとめて1つの積層素子を得、この積層素子をさらに複数個積層させて絶縁性のテープでまとめ、この素子に電解液を含浸させた後、有底筒状の外装ケース内に収容することにより構成されたものである場合には、素子止めテープを介して負極と接触している正極と素子止めテープの間に上記固体塩基が設けられていると、固体塩基にプロトンが吸着され、電解液の酸性化とプロピレンカーボネート等の有機溶媒の分解が抑制されるため好ましい。   The electric double layer capacitor is a multilayer type, that is, a plurality of positive electrodes and negative electrodes are alternately stacked with a separator interposed therebetween, and a single multilayer element is obtained by combining them with an insulating element stopper tape. If it is constructed by laminating and packing together with an insulating tape, impregnating this element with an electrolyte, and then housing it in a bottomed cylindrical outer case, the element is attached via a tape. If the solid base is provided between the positive electrode that is in contact with the negative electrode and the device stopper tape, protons are adsorbed to the solid base, and acidification of the electrolytic solution and decomposition of organic solvents such as propylene carbonate are suppressed. Therefore, it is preferable.

固体塩基の種類には特に限定が無く、非水系電解液に不溶で、安定であり、電解液及び電解質に悪影響を及ぼさないものであれば良いが、無定形シリカアルミナ又は無定形シリカマグネシアが好ましい。   There is no particular limitation on the type of solid base, as long as it is insoluble in a non-aqueous electrolyte solution, stable and does not adversely affect the electrolyte solution and electrolyte, but amorphous silica alumina or amorphous silica magnesia is preferred. .

本発明の電気二重層キャパシタによると、固体塩基が外装ケース内に含まれているため、負極と対向していない正極上で発生したプロトンが固体塩基に吸着され、電解液の酸性化とプロピレンカーボネート等の有機溶媒の分解が抑制され、有機溶媒の分解物である不溶成分の発生が抑制され、高温使用下における電気二重層キャパシタの容量の低下及び内部抵抗の上昇が大幅に抑制される。   According to the electric double layer capacitor of the present invention, since the solid base is contained in the outer case, protons generated on the positive electrode not facing the negative electrode are adsorbed on the solid base, and the acidification of the electrolyte and propylene carbonate The decomposition of the organic solvent such as the above is suppressed, the generation of the insoluble component that is the decomposition product of the organic solvent is suppressed, and the decrease in the capacity and the increase in the internal resistance of the electric double layer capacitor under high temperature use are greatly suppressed.

巻回型電気二重層キャパシタの断面の概略図を示している。The schematic of the cross section of a winding type electric double layer capacitor is shown. 外装ケース内に固体塩基を含むキャパシタと含まないキャパシタについて、高温負荷試験における容量変化率を比較した図である。It is the figure which compared the capacity | capacitance change rate in a high-temperature load test about the capacitor which does not contain the solid base in the exterior case, and a capacitor. 外装ケース内に固体塩基を含むキャパシタと含まないキャパシタについて、高温負荷試験における直流内部抵抗変化率を比較した図である。It is the figure which compared the direct current | flow internal resistance change rate in the high temperature load test about the capacitor which does not contain the solid base in the exterior case, and a capacitor.

以下、本発明を詳細に説明する。以下では巻回型電気二重層キャパシタを例として説明するが、本発明は巻回型に限定されず、積層型、コイン型、ボタン型、ラミネート型等のあらゆる構造のキャパシタに適用される。   Hereinafter, the present invention will be described in detail. Hereinafter, a wound type electric double layer capacitor will be described as an example. However, the present invention is not limited to a wound type, and can be applied to capacitors having any structure such as a laminated type, a coin type, a button type, and a laminated type.

図1は、巻回型電気二重層キャパシタの断面の概略図を示している。巻回型電気二重層キャパシタ1における巻回素子10は、帯状の集電体の両面に分極性電極が設けられた構成の正極3、負極4を、これらの間に挟んだセパレータ2と共に円筒状の巻芯5の周囲に巻きつけることにより得られる。そして、この巻回素子10に非水系電解液を含浸させた後、有底筒状の外装ケース7内に収容し、封口体8により密封することにより、巻回型電気二重層キャパシタ1が構成される。記号6は、集電体に接続されるリード端子を示している。   FIG. 1 shows a schematic cross-sectional view of a wound electric double layer capacitor. The winding element 10 in the wound electric double layer capacitor 1 has a cylindrical shape together with a separator 2 sandwiched between a positive electrode 3 and a negative electrode 4 each having a polarizable electrode provided on both sides of a strip-shaped current collector. It is obtained by winding around the core 5. The winding element 10 is impregnated with a non-aqueous electrolyte solution, then housed in a bottomed cylindrical outer case 7 and sealed with a sealing body 8, whereby the wound electric double layer capacitor 1 is configured. Is done. Symbol 6 indicates a lead terminal connected to the current collector.

集電体としては、アルミニウム、ニッケル、鋼、カーボン等の導電材料を使用することができる。また、分極性電極は、比表面積の大きな活性炭、カーボンナノチューブなどの炭素材料と、カーボンブラックなどの導電材と、ポリテトラフルオロエチレン、ポリフッ化ビニリデン、テトラフルオロエチレン−ヘキサフルオロプロピレンコポリマー、ポリフッ化ビニル、カルボキシメチルセルロース等のバインダとから構成される。そして、バインダを溶解した溶媒に上記炭素材料及び導電材を分散させ、得られた分散液をドクターブレード法などによって集電体上に塗工し、乾燥することにより、正極3及び負極4を得ることができる。セパレータ2としては、セルロース繊維布、ポリオレフィン繊維不織布、ガラス繊維不織布等が好適に使用される。   As the current collector, a conductive material such as aluminum, nickel, steel, or carbon can be used. Polarizable electrodes include carbon materials such as activated carbon and carbon nanotubes with a large specific surface area, conductive materials such as carbon black, polytetrafluoroethylene, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, and polyvinyl fluoride. And a binder such as carboxymethylcellulose. Then, the carbon material and the conductive material are dispersed in a solvent in which the binder is dissolved, and the obtained dispersion is applied onto a current collector by a doctor blade method or the like and dried to obtain the positive electrode 3 and the negative electrode 4. be able to. As the separator 2, a cellulose fiber cloth, a polyolefin fiber nonwoven fabric, a glass fiber nonwoven fabric or the like is preferably used.

非水系電解液の溶媒としては、電気化学的に安定なエチレンカーボネート、プロピレンカーボネート、ブチレンカーボネート、ジメチルカーボネート、エチルメチルカーボネート、ジエチルカーボネート、スルホラン、3−メチルスルホラン、γ−ブチロラクトン、アセトニトリル及びジメトキシエタン、N−メチル−2−ピロリドン、ジメチルホルムアミド又はこれらの混合物を好適に使用することができる。   As the solvent for the non-aqueous electrolyte, electrochemically stable ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, sulfolane, 3-methyl sulfolane, γ-butyrolactone, acetonitrile, and dimethoxyethane, N-methyl-2-pyrrolidone, dimethylformamide or a mixture thereof can be preferably used.

また、非水系電解液の電解質としては、第4級アンモニウムカチオン又は第4級ホスホニウムカチオンを有する第4級アンモニウム塩又は第4級ホスホニウム塩を使用することができる。例えば、R又はRで表されるカチオン(ただし、R、R、R、Rは炭素数1〜6のアルキル基を表す)と、PF 、BF 、ClO 、N(CFSO 、CFSO 、C(SOCF 、N(SO 、AsF 又はSbF からなるアニオンとからなる塩、又はこれらの混合物を好適に使用することができる。特に、アニオンとしてPF 、BF 、ClO 、N(CFSO を使用した塩が溶質として好ましい。 Further, as the electrolyte of the non-aqueous electrolyte solution, a quaternary ammonium salt or a quaternary phosphonium salt having a quaternary ammonium cation or a quaternary phosphonium cation can be used. For example, a cation represented by R 1 R 2 R 3 R 4 N + or R 1 R 2 R 3 R 4 P + (where R 1 , R 2 , R 3 and R 4 are alkyl having 1 to 6 carbon atoms) Group), PF 6 , BF 4 , ClO 4 , N (CF 3 SO 3 ) 2 , CF 3 SO 3 , C (SO 2 CF 3 ) 3 , N (SO 2 C 2 A salt composed of an anion composed of F 5 ) 2 , AsF 6 or SbF 6 , or a mixture thereof can be suitably used. In particular, a salt using PF 6 , BF 4 , ClO 4 or N (CF 3 SO 3 ) 2 as the anion is preferable as the solute.

本発明では、外装ケース7の内部に固体塩基が設けられる。固体塩基としては、非水系電解液中に不溶で、安定であり、電解液及び電解質に悪影響を及ぼさないものであれば、特に限定なく使用することができ、SiO−Al、SiO−MgO、SiO−CaO、Al−MgOなどの複合酸化物、Al、MgO、CaO、SrO、BaO、ZrO、TiOなどの酸化物、陰イオン交換樹脂、ゼオライト、活性炭などを使用することができ、SiO−Al、SiO−MgOは、表面積が大きく、プロトンとの反応性に富むため、好ましく使用することができる。これらは、窒素中で加熱処理して使用することもできる。 In the present invention, a solid base is provided inside the outer case 7. The solid base can be used without particular limitation as long as it is insoluble and stable in the non-aqueous electrolyte solution and does not adversely affect the electrolyte solution and the electrolyte. SiO 2 —Al 2 O 3 , SiO 2 2 -MgO, SiO 2 -CaO, composite oxides such as Al 2 O 3 -MgO, Al 2 O 3, MgO, CaO, SrO, BaO, oxides such as ZrO 2, TiO 2, anion-exchange resins, zeolites Activated carbon can be used, and SiO 2 —Al 2 O 3 and SiO 2 —MgO are preferably used because they have a large surface area and are highly reactive with protons. These can also be used after heat treatment in nitrogen.

固体塩基は、円筒状の巻芯5の筒内aに収容してもよく、外装ケース7内の底部b、すなわち、底面7aと巻回素子10との間の位置に配置してもよく、外装ケース7内の上部c、すなわち、封口体8と巻回素子10との間の位置に配置してもよく、外装ケース7内の側部d、すなわち、外装ケース7の内周面と巻回素子10との間の位置に配置してもよい。電気二重層キャパシタの使用過程において、固体塩基が重力の作用により外装ケース内で下方に移動するが、負極と対向していない正極面上で発生したプロトンを含む電解液も下方に移動し、固体塩基によりプロトンが吸着され、電解液の酸性化とプロピレンカーボネート等の有機溶媒の分解が抑制される。固体塩基は、外装ケース7内の底部bに配置すると、プロトンを含む電解液が下方に移動して、固体塩基によりプロトンが吸着され、電解液の酸性化とプロピレンカーボネート等の有機溶媒の分解が抑制されるので好ましく、また、固体塩基を巻芯内aに収容しておくと、正極の巻芯の周面に面する側で発生したプロトンが効率的に吸着されるため好ましい。   The solid base may be accommodated in the cylinder a of the cylindrical winding core 5, or may be disposed at the bottom b in the outer case 7, that is, at a position between the bottom surface 7a and the winding element 10, You may arrange | position in the position between the upper part c in the exterior case 7, ie, the sealing body 8, and the winding element 10, and the side part d in the exterior case 7, ie, the inner peripheral surface of the exterior case 7, and winding. You may arrange | position in the position between the turning elements 10. In the process of using the electric double layer capacitor, the solid base moves downward in the outer case by the action of gravity, but the electrolyte containing protons generated on the positive electrode surface not facing the negative electrode also moves downward, Protons are adsorbed by the base and acidification of the electrolyte and decomposition of organic solvents such as propylene carbonate are suppressed. When the solid base is disposed at the bottom b in the outer case 7, the electrolyte solution containing protons moves downward, the protons are adsorbed by the solid base, and acidification of the electrolyte solution and decomposition of an organic solvent such as propylene carbonate are performed. The solid base is preferably contained in the core a, because protons generated on the side facing the peripheral surface of the positive electrode core are efficiently adsorbed.

以下、本発明を実施例を用いて説明するが、本発明は以下の実施例に限定されない。
実施例1
活性炭2.6g、カーボンブラック0.28g、及びイソプロピルアルコール5.5gを撹拌し、この混合物に、60%ポリテトラフルオロエチレン水溶液5.2gを混合して混練物を作製し、この混練物を圧延用ローラーにより圧延して、150μmのシートを作製した。
EXAMPLES Hereinafter, although this invention is demonstrated using an Example, this invention is not limited to a following example.
Example 1
2.6 g of activated carbon, 0.28 g of carbon black, and 5.5 g of isopropyl alcohol are stirred, and a mixture is mixed with 5.2 g of a 60% polytetrafluoroethylene aqueous solution. The kneaded product is rolled. A 150 μm sheet was prepared by rolling with a roller.

このシートを、リード端子を設けたアルミニウムエッチング箔(集電体)に、カーボン系接着剤を用いて接着し、これを正極及び負極とした。   This sheet was bonded to an aluminum etching foil (current collector) provided with lead terminals using a carbon-based adhesive, and this was used as a positive electrode and a negative electrode.

このようにして作製した正極及び負極をセルロース系セパレータを介して配置し、円筒状の巻芯に正極が巻芯の周面に対向するようにして巻回し、巻回型の電気二重層キャパシタ素子を作製した。この素子に、1Mの四フッ化ホウ酸テトラエチルアンモニウム/プロピレンカーボネート電解液を含浸し、アルミニウム製の外装ケース内に入れた後、巻芯内に、窒素中、500℃で3時間処理したSiO−Al粉末0.8gを収容した。その後、開口部を封口体で封口し、電圧を印加することにより、径30mm、長さ105mmの固体塩基を内蔵する巻回型電気二重層キャパシタセルを作製した。 A positive electrode and a negative electrode produced in this manner are arranged via a cellulose separator, and wound around a cylindrical winding core so that the positive electrode faces the peripheral surface of the winding core. Was made. This element was impregnated with 1M tetraethylammonium tetrafluoroborate / propylene carbonate electrolytic solution, put in an aluminum outer case, and then treated with SiO 2 in nitrogen at 500 ° C. for 3 hours in the core. containing the -al 2 O 3 powder 0.8 g. Thereafter, the opening was sealed with a sealing body, and a voltage was applied to produce a wound electric double layer capacitor cell containing a solid base having a diameter of 30 mm and a length of 105 mm.

比較例1
SiO−Al粉末を使用する点を除いて実施例1の手順を繰り返し、固体塩基を内蔵しない巻回型電気二重層キャパシタセルを作製した。
Comparative Example 1
The procedure of Example 1 was repeated except that SiO 2 —Al 2 O 3 powder was used, and a wound electric double layer capacitor cell not incorporating a solid base was produced.

実施例1と比較例1の電気二重層キャパシタについて、温度70℃、電圧2.5Vの負荷試験を2000時間行った。図2には、実施例1と比較例1についての放電容量変化率を、図3には、実施例1と比較例1についての直流内部抵抗変化率を示した。   About the electric double layer capacitor of Example 1 and Comparative Example 1, a load test at a temperature of 70 ° C. and a voltage of 2.5 V was performed for 2000 hours. FIG. 2 shows the discharge capacity change rate for Example 1 and Comparative Example 1, and FIG. 3 shows the DC internal resistance change rate for Example 1 and Comparative Example 1.

図2、図3からわかるように、比較例1の固体塩基を内蔵しない電気二重層キャパシタに比較して、実施例1の固体塩基を内蔵する電気二重層キャパシタは、70℃の高温下においても、容量及び内部抵抗の変化が小さく、特に1000時間経過後の変化がほとんど認められず、長寿命であることがわかる。また、試験後のキャパシタを分解して目視検査したところ、比較例1のキャパシタにはプロピレンカーボネートの分解物である不溶成分が付着していたが、実施例1のキャパシタには不溶成分の付着がほとんど認められなかった。   As can be seen from FIGS. 2 and 3, the electric double layer capacitor containing the solid base of Example 1 is higher than the electric double layer capacitor containing the solid base of Comparative Example 1 even at a high temperature of 70 ° C. It can be seen that the change in the capacitance and the internal resistance is small, and especially the change after 1000 hours is hardly observed, and the life is long. Further, when the capacitor after the test was disassembled and visually inspected, the insoluble component, which was a decomposition product of propylene carbonate, was adhered to the capacitor of Comparative Example 1, but the insoluble component was adhered to the capacitor of Example 1. Almost not recognized.

Claims (5)

分極性を有する正極及び負極とこれらの間に配置された非水系電解液を保持したセパレータとを有するキャパシタ素子が外装ケース内に収容されている電気二重層キャパシタであって、
前記外装ケース内に固体塩基が含まれていることを特徴とする電気二重層キャパシタ。
An electric double layer capacitor in which a capacitor element having a positive electrode and a negative electrode having polarities and a separator holding a non-aqueous electrolyte disposed therebetween is housed in an outer case,
An electric double layer capacitor characterized in that a solid base is contained in the outer case.
前記電気二重層キャパシタが、帯状の正極と負極とをこれらの間に挟んだセパレータと共に円筒状の巻芯の周囲に正極が巻芯の周面に面するように巻きつけることによって巻回素子を得、該巻回素子に非水系電解液を含浸させた後、有底筒状の外装ケース内に収容することにより構成されたものであり、
前記固体塩基が前記外装ケース内の底部に設けられている、請求項1に記載の電気二重層キャパシタ。
The electric double layer capacitor is wound with a separator sandwiched between a belt-like positive electrode and a negative electrode, and wound around the cylindrical core so that the positive electrode faces the peripheral surface of the core. Obtained, impregnated with a non-aqueous electrolyte in the winding element, and then housed in a bottomed cylindrical outer case,
The electric double layer capacitor according to claim 1, wherein the solid base is provided at a bottom portion in the outer case.
前記固体塩基が前記円筒状の巻芯内に収容されている、請求項2に記載の電気二重層キャパシタ。   The electric double layer capacitor according to claim 2, wherein the solid base is accommodated in the cylindrical core. 電気二重層キャパシタが、複数枚の正極と負極とをセパレータを挟んで交互に積層して絶縁性の素子止めテープでまとめて1つの積層素子を得、該積層素子をさらに複数個積層させて絶縁性のテープでまとめ、この素子に電解液を含浸させた後、有底筒状の外装ケース内に収容することにより構成されたものであり、
前記固体塩基が素子止めテープを介して負極と接触している正極と素子止めテープの間に設けられている、請求項1に記載の電気二重層キャパシタ。
An electric double layer capacitor is formed by alternately laminating a plurality of positive electrodes and negative electrodes with a separator interposed therebetween and collecting them with an insulating element stop tape to obtain one laminated element, and further laminating a plurality of the laminated elements for insulation. It is composed by packing it with a conductive tape, impregnating this element with an electrolytic solution, and then housing it in a bottomed cylindrical outer case,
2. The electric double layer capacitor according to claim 1, wherein the solid base is provided between a positive electrode in contact with a negative electrode via an element stopper tape and an element stopper tape.
前記固体塩基が無定形シリカアルミナ又は無定形シリカマグネシアである、請求項1〜4のいずれか1項に記載の電気二重層キャパシタ。   The electric double layer capacitor according to any one of claims 1 to 4, wherein the solid base is amorphous silica alumina or amorphous silica magnesia.
JP2009088284A 2009-03-31 2009-03-31 Electric double layer capacitor Pending JP2010239085A (en)

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Cited By (2)

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CN104701029A (en) * 2015-01-06 2015-06-10 宁波南车新能源科技有限公司 Inorganic nanoparticle containing organic electrolyte solution of super capacitor
US9368292B2 (en) 2012-11-13 2016-06-14 Kuraray Chemical Co., Ltd. Carbon material for polarizable electrodes and method for producing same

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JP2003297699A (en) * 2002-03-29 2003-10-17 Nec Tokin Corp Electric double-layer capacitor
JP2006261516A (en) * 2005-03-18 2006-09-28 Honda Motor Co Ltd Electric double layer capacitor
JP2007073810A (en) * 2005-09-08 2007-03-22 Honda Motor Co Ltd Electric double-layer capacitor
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JP2003297699A (en) * 2002-03-29 2003-10-17 Nec Tokin Corp Electric double-layer capacitor
JP2006261516A (en) * 2005-03-18 2006-09-28 Honda Motor Co Ltd Electric double layer capacitor
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US9368292B2 (en) 2012-11-13 2016-06-14 Kuraray Chemical Co., Ltd. Carbon material for polarizable electrodes and method for producing same
CN104701029A (en) * 2015-01-06 2015-06-10 宁波南车新能源科技有限公司 Inorganic nanoparticle containing organic electrolyte solution of super capacitor

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