JP2010141065A - Electric storage device - Google Patents

Electric storage device Download PDF

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JP2010141065A
JP2010141065A JP2008315155A JP2008315155A JP2010141065A JP 2010141065 A JP2010141065 A JP 2010141065A JP 2008315155 A JP2008315155 A JP 2008315155A JP 2008315155 A JP2008315155 A JP 2008315155A JP 2010141065 A JP2010141065 A JP 2010141065A
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negative electrode
electrode
storage device
lithium
positive electrode
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Riza Miyagawa
里咲 宮川
Yukinori Hado
之規 羽藤
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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
    • Y02E60/10Energy storage using batteries
    • 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
    • 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
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50Manufacturing or production processes characterised by the final manufactured product

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric storage device having high output density and reducing costs. <P>SOLUTION: A polarizing electrode is used for a positive electrode 1, and an electrode that can be reversibly doped with lithium is used for a negative electrode 2. A separator 3 is arranged between the positive electrode 1 and the negative electrode 2. A positive electrode current collector 4 and a negative electrode current collector 5 for extracting an electric charge are arranged in the positive electrode and the negative electrode. The positive electrode 1 and the negative electrode 2 are alternately laminated through the separator in the configuration. A lithium metal 6 that is a lithium supply source of the negative electrode is opposed to the negative electrode. An electric storage device has such a configuration as to be impregnated with an electrolyte 7 that is a nonaqueous solution containing lithium ions. In the electric storage device, a carbon material with an electric potential adjusted beforehand at 120 mV (Li/Li<SP>+</SP>) or below is used for the negative electrode 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、二次電池および電気二重層キャパシタの代替又は補助電力供給源としてのハイブリットキャパシタと呼ばれる蓄電デバイスに関するものである。   The present invention relates to an electricity storage device called a hybrid capacitor as an alternative or auxiliary power supply source for a secondary battery and an electric double layer capacitor.

電気二重層キャパシタは、急速に充電ができ、大電流で放電することができ、さらに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、ニッケル水素二次電池やリチウムイオン二次電池などの二次電池にはない特長を有している。   Electric double layer capacitors can be charged quickly, can be discharged with a large current, and even if they are charged and discharged more than 10,000 times, their characteristics do not deteriorate. It has features not found in secondary batteries such as batteries.

このため、近年、大電流を必要するハイパワー用途や電力補助供給源として、電気二重層キャパシタに対する期待が高まっている。   For this reason, in recent years, expectations for electric double layer capacitors have increased as high power applications and power auxiliary supply sources that require large currents.

電気二重層キャパシタは、活性炭を主成分とした分極性電極層に電解液を含浸し、これら分極性電極はセパレータを介して対向配置し、キャパシタ素子が構成されている。そして、各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。   In an electric double layer capacitor, a polarizable electrode layer containing activated carbon as a main component is impregnated with an electrolyte, and these polarizable electrodes are arranged to face each other via a separator to constitute a capacitor element. Then, an electric double layer is formed at the interface between each polarizable electrode layer and the electrolytic solution.

この電気二重層キャパシタに電圧が印加されることにより、この電気二重層のもつ静電容量分の電荷が蓄積される。   By applying a voltage to the electric double layer capacitor, charges corresponding to the capacitance of the electric double layer are accumulated.

近年、正極に電気二重層キャパシタ用として用いられる分極性電極を使用し、負極にリチウムイオンを吸蔵、脱離しうる炭素材料を使用したハイブリットキャパシタと呼ばれる蓄電デバイスが提案されている。このハイブリッドキャパシタは、負極にあらかじめリチウムイオンを吸蔵(ドープ)させて、ハイブリッドキャパシタの電圧(正極電位と負極電位の電位差)を高くすることで、高耐電圧化、高エネルギー密度化している。   In recent years, an electric storage device called a hybrid capacitor has been proposed in which a polarizable electrode used for an electric double layer capacitor is used for a positive electrode and a carbon material capable of inserting and extracting lithium ions is used for a negative electrode. In this hybrid capacitor, lithium ions are occluded (doped) in advance in the negative electrode to increase the voltage of the hybrid capacitor (potential difference between the positive electrode potential and the negative electrode potential), thereby increasing the withstand voltage and increasing the energy density.

また、ハイブリッドキャパシタの正極には、電気二重層キャパシタで一般的に使用される分極性電極を使用するため、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、それにより電荷が蓄積される。そのため、リチウムイオン二次電池のように、正極活物質自体にリチウムイオンを吸蔵、脱離させる化学反応を伴わず、充放電サイクルに優れた蓄電デバイスを提供することが出来る。   In addition, since a polarizable electrode generally used in an electric double layer capacitor is used for the positive electrode of the hybrid capacitor, an electric double layer is formed at the interface between the polarizable electrode layer and the electrolyte solution, thereby charging Accumulated. Therefore, unlike the lithium ion secondary battery, it is possible to provide an electricity storage device that is excellent in charge and discharge cycles without being accompanied by a chemical reaction that causes the positive electrode active material itself to occlude and desorb lithium ions.

特許文献1には、負極の電極とリチウム金属箔とを接触させて炭素材料にリチウムイオンをドープさせたものを負極に用いるハイブリットキャパシタが提案されている。また、特許文献2、3には、リチウム金属と負極を電気化学的に接触させることによりリチウムイオンが負極にドープされるという電池またはキャパシタが提案されている。   Patent Document 1 proposes a hybrid capacitor in which a negative electrode and a lithium metal foil are brought into contact with each other and a carbon material doped with lithium ions is used for the negative electrode. Patent Documents 2 and 3 propose batteries or capacitors in which lithium ions are doped into the negative electrode by bringing lithium metal and the negative electrode into electrochemical contact.

特開平8−107048号公報Japanese Patent Laid-Open No. 8-1007048 国際公開第WO00/07255号パンフレットInternational Publication No. WO00 / 07255 Pamphlet 国際公開第WO2003/003395号パンフレットInternational Publication No. WO2003 / 003395 Pamphlet

しかし、特許文献1〜3のように、あらかじめ負極とリチウム金属を接触させる場合には、負極へリチウムイオンをドープする量を調整できないため、抵抗にばらつきが生じる問題があった。また、ハイブリッドキャパシタは、電気二重層キャパシタと比べて抵抗が高いため、更なる高出力化など高性能化が望まれている。   However, as in Patent Documents 1 to 3, when the negative electrode and the lithium metal are contacted in advance, the amount of doping of lithium ions into the negative electrode cannot be adjusted. In addition, since the hybrid capacitor has a higher resistance than the electric double layer capacitor, higher performance such as higher output is desired.

本発明の課題は、正極に分極性電極を使用し、負極はリチウムを可逆的にドープ可能な電極であり、電解液にリチウムイオンを含有する非水系の溶液を使用したハイブリッドキャパシタと呼ばれる蓄電デバイスにおいて、更に出力密度が高く、かつ低コスト化が図られた蓄電デバイスを提供することにある。   An object of the present invention is to provide a power storage device called a hybrid capacitor using a polarizable electrode as a positive electrode, an electrode capable of reversibly doping lithium, and a non-aqueous solution containing lithium ions as an electrolyte. Therefore, an object of the present invention is to provide an electricity storage device with higher output density and lower cost.

本発明は、上記課題を解決するためになされたものであり、正極に分極性電極を、負極にリチウムを可逆的にドープ可能な電極を、電解液にリチウムイオンを含有する非水系の溶液を使用し、セパレータを介して交互に積層した正極と負極で構成された電極ユニットにおいては、負極にドープされるリチウム量により負極電位が変わり、かかる負極電位とハイブリッドキャパシタの抵抗や出力密度が密接に関係し、電位をあらかじめ2〜120mV(Li/Li+)に調整した炭素材料を負極に用いることにより、上記の課題を解決できることを見出したものである。即ち、本発明は、以下の構成を有することを特徴とするものである。 The present invention has been made in order to solve the above-mentioned problems. A polarizable electrode is used as a positive electrode, an electrode capable of reversibly doping lithium is used as a negative electrode, and a non-aqueous solution containing lithium ions is used as an electrolytic solution. In an electrode unit composed of positive and negative electrodes that are alternately stacked via separators, the negative electrode potential changes depending on the amount of lithium doped into the negative electrode, and the negative electrode potential closely matches the resistance and output density of the hybrid capacitor. It has been found that the above problem can be solved by using a carbon material whose potential is adjusted to 2 to 120 mV (Li / Li + ) in advance for the negative electrode. That is, the present invention is characterized by having the following configuration.

本発明の蓄電デバイスは、分極性電極を主体とする正極と、リチウムを可逆的にドープ可能で電位をあらかじめ2〜120mV(Li/Li+)に調整した炭素材料を主体とする負極とをセパレータを介して交互に積層し、電解液にリチウムイオンを含有する非水系の溶液を使用したことを特徴とする。 The electricity storage device of the present invention is a separator comprising a positive electrode mainly composed of a polarizable electrode and a negative electrode mainly composed of a carbon material which can be reversibly doped with lithium and whose potential is adjusted to 2 to 120 mV (Li / Li + ) in advance. It is characterized by using a non-aqueous solution containing lithium ions as an electrolytic solution.

前記負極は、電極ユニットの負極面に対向して配置されたリチウム供給源からリチウムをドープさせたことを特徴とする。   The negative electrode is characterized in that lithium is doped from a lithium supply source disposed to face the negative electrode surface of the electrode unit.

また、前記負極は集電体に、低コストかつ電極作製が簡便な箔を用いることが望ましい。   In addition, it is desirable that the negative electrode be made of a foil that is low-cost and easy to produce an electrode for the current collector.

また、前記負極は、低抵抗かつ、低コストとなる難黒鉛化炭素材料あるいはリチウムイオン二次電池の負極活物質に用いられる黒鉛材料を主成分としたことを特徴とする。   In addition, the negative electrode is characterized in that the main component is a non-graphitizable carbon material or a graphite material used for a negative electrode active material of a lithium ion secondary battery that has low resistance and low cost.

また、前記非水系の溶液は、少なくともプロピレンカーボネートまたはエチレンカーボネートいずれかを有することを特徴とする。   The non-aqueous solution contains at least either propylene carbonate or ethylene carbonate.

また、正極は活性炭を主成分とする分極性電極を用いると、高容量かつ高耐久性が得られるため、望ましい。   Further, it is desirable to use a polarizable electrode mainly composed of activated carbon as the positive electrode because high capacity and high durability can be obtained.

本発明によれば、負極に電位をあらかじめ2〜120mV(Li/Li+)に調整した炭素材料を用いることにより、出力密度が高くなり、さらに低抵抗な負極材料として難黒鉛化炭素材料あるいはリチウムイオン二次電池の負極活物質に用いられる黒鉛材料を活用することで更なる低抵抗化が図られる。また、負極電位を0mV近傍まで極端に下げなくても、低抵抗な負極が得られることがわかり、集電体に高価となる貫通孔を用いなくても、抵抗低減するのに充分量のドープがなされ、箔を用いることで電極作製工程を簡略化させることができ低コストの蓄電デバイスを提供することができる。 According to the present invention, by using a carbon material whose potential has been adjusted to 2 to 120 mV (Li / Li + ) in advance for the negative electrode, the power density is increased, and a non-graphitizable carbon material or lithium as a negative electrode material having a low resistance. The resistance can be further reduced by utilizing the graphite material used for the negative electrode active material of the ion secondary battery. Further, it can be seen that a low-resistance negative electrode can be obtained without extremely reducing the negative electrode potential to near 0 mV, and a sufficient amount of doping can be used to reduce the resistance without using an expensive through-hole in the current collector. By using the foil, the electrode manufacturing process can be simplified, and a low-cost power storage device can be provided.

次に、本発明の実施の形態について図面を参照して説明する。図1に、本発明に係る蓄電デバイスの断面図を示す。本発明の蓄電デバイスは、正極1に分極性電極、負極2にリチウムを可逆的にドープ可能な電極が用いられ、正極1と負極2の間にセパレータ3が配置され、また正極および負極には電荷を取り出すための正極集電体4、負極集電体5が配置され、正極1と負極2はセパレータを介して交互に積層して構成された電極ユニットとなっている。さらに、負極のリチウム供給源となるリチウム金属6を負極に対向させ、リチウムイオンを含有する非水系溶液である電解液7が含浸された構成となっている。   Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a cross-sectional view of an electricity storage device according to the present invention. In the electricity storage device of the present invention, a polarizable electrode is used for the positive electrode 1, an electrode capable of reversibly doping lithium is used for the negative electrode 2, a separator 3 is disposed between the positive electrode 1 and the negative electrode 2, and A positive electrode current collector 4 and a negative electrode current collector 5 for taking out electric charges are arranged, and the positive electrode 1 and the negative electrode 2 are electrode units that are alternately stacked via separators. Further, the lithium metal 6 serving as a lithium supply source of the negative electrode is opposed to the negative electrode, and the electrolyte solution 7 which is a non-aqueous solution containing lithium ions is impregnated.

上記、電極ユニットを、リチウムイオンを含有する非水系溶液である電解液に含浸されると、リチウム金属をリチウム源として負極にドープされる。このとき、本発明において、あらかじめ負極にリチウムをドープさせる手段は特に限定されない。例えば、負極とリチウム金属を物理的に短絡させる方法でも、または電気化学的にドープさせる方法いずれでもよい。   When the electrode unit is impregnated with an electrolytic solution that is a non-aqueous solution containing lithium ions, the negative electrode is doped with lithium metal as a lithium source. At this time, in the present invention, means for doping lithium in the negative electrode in advance is not particularly limited. For example, either a method of physically short-circuiting the negative electrode and lithium metal or a method of electrochemically doping may be used.

負極の電位は、2〜120mV(Li/Li+)に調整することが好ましい。120mVより高いと、負極におけるリチウムイオンの電荷移動抵抗が大きくなるため、抵抗は上昇し、出力密度は下がるため好ましくない。また、2mV未満では、大電流のサイクル充放電試験において、負極の電位は0Vより小さくなり、負極上にリチウムまたはリチウムを含有する化合物を析出する可能性がある。そのため、2〜120mVの範囲にすることが好ましい。 The potential of the negative electrode is preferably adjusted to 2 to 120 mV (Li / Li + ). If it is higher than 120 mV, the charge transfer resistance of lithium ions at the negative electrode increases, so that the resistance increases and the output density decreases, which is not preferable. If it is less than 2 mV, the potential of the negative electrode becomes smaller than 0 V in a large current cycle charge / discharge test, and lithium or a lithium-containing compound may be deposited on the negative electrode. Therefore, it is preferable to make it the range of 2-120 mV.

また、負極のリチウムドープ供給源は、負極に対向させることが望ましい。負極に対向させないと、負極とリチウム供給源との拡散距離が大きくなり、ドープに時間を要するとともに負極の電荷移動抵抗が高くなる。また、リチウム供給源は、負極と対向した場所なら電極ユニットの中に、何枚あっても構わない。   Further, the lithium-doped supply source of the negative electrode is desirably opposed to the negative electrode. If it is not made to oppose the negative electrode, the diffusion distance between the negative electrode and the lithium supply source becomes large, and it takes time for doping and the charge transfer resistance of the negative electrode becomes high. Further, there may be any number of lithium supply sources in the electrode unit as long as it is opposed to the negative electrode.

リチウムイオン供給源には、リチウム金属あるいはリチウム−アルミニウム合金のようにリチウムイオンを供給できる物質を使用することができる。   As the lithium ion supply source, a material capable of supplying lithium ions such as lithium metal or lithium-aluminum alloy can be used.

負極集電体の材質としては、一般にリチウム系電池に提案されている種々の材質を用いることができ、負極集電体およびリチウム電極集電体にはステンレス、銅、ニッケル等をそれぞれ用いることができる。また、負極電位を0mV近傍まで極端に下げなくても、低抵抗な負極が得られることがわかり、集電体に高価な貫通孔を用いなくても、抵抗低減するのに充分量のドープがなされることを確認したことから、集電体は、箔を用いることができる。そのため、貫通孔を有する集電体への処理がなくなり低コストが図れる。また、貫通孔を有する箔を用いると、活物質を塗布する前処理として、導電剤や接着剤を用いて貫通孔を塞ぐ、いわゆる下塗り処理が必要となるが、本発明によりこの工程は必要なくなることから、電極作製工程を簡略にすることができる。   As the material of the negative electrode current collector, various materials generally proposed for lithium-based batteries can be used, and stainless steel, copper, nickel, etc. are used for the negative electrode current collector and the lithium electrode current collector, respectively. it can. Further, it can be seen that a low resistance negative electrode can be obtained even if the negative electrode potential is not extremely lowered to around 0 mV, and a sufficient amount of dope is added to reduce the resistance without using an expensive through-hole in the current collector. Since it was confirmed that the current collector is made, a foil can be used as the current collector. For this reason, there is no need to process the current collector having a through hole, and the cost can be reduced. In addition, when a foil having a through hole is used, a so-called undercoating treatment is required as a pretreatment for applying the active material, which closes the through hole using a conductive agent or an adhesive, but this step is not necessary according to the present invention. Therefore, the electrode manufacturing process can be simplified.

負極集電体の厚みは、5〜20μmであることが最も好ましい。5μmより薄くなると電極の塗工工程で作業性が低下し、電極を作製できない。また、20μmより厚くなると、電極ユニットあたりの集電体体積が大きくなり、エネルギー密度が低下する。そのため、低抵抗かつ作業性のよい5〜20μmの厚みが望ましい。   The thickness of the negative electrode current collector is most preferably 5 to 20 μm. If the thickness is less than 5 μm, workability deteriorates in the electrode coating process, and the electrode cannot be produced. Moreover, when it becomes thicker than 20 micrometers, the collector volume per electrode unit will become large, and an energy density will fall. Therefore, a thickness of 5 to 20 μm with low resistance and good workability is desirable.

また、集電体と負極の間には、低抵抗化のために接着剤や下塗り剤を塗工することもできる。   In addition, an adhesive or a primer can be applied between the current collector and the negative electrode to reduce resistance.

負極の主成分である負極活物質は、リチウムイオンを可逆的にドープできる物質から形成される。例えば、リチウムイオン二次電池の負極に用いられる黒鉛材料や、難黒鉛化炭素材料、コークスなどの炭素材料、ポリアセン系物質等を挙げることができるが、低抵抗化や低コスト化を考慮すると、好ましくは、黒鉛材料や、難黒鉛化炭素材料がよい。また、平均粒径が5μm以下であることが好ましい。   The negative electrode active material that is the main component of the negative electrode is formed of a material that can be reversibly doped with lithium ions. For example, a graphite material used for a negative electrode of a lithium ion secondary battery, a non-graphitizable carbon material, a carbon material such as coke, a polyacene-based substance, and the like can be mentioned, but considering low resistance and low cost, Preferably, graphite material and non-graphitizable carbon material are good. Moreover, it is preferable that an average particle diameter is 5 micrometers or less.

次に、リチウムイオンを含有する非水系の溶液から構成される電解液の溶媒は、例えばエチレンカーボネート、プロピレンカーボネート、ジメチルカーボネート、ジエチルカーボネート、メチルエチルカーボネート、γ―ブチルラクトン、アセトニトリル、ジメトキシエタン、テトラヒドロフラン、ジオキソラン、塩化メチレン、スルホラン等が挙げられる、さらに、これらの溶媒を2種類以上混合した混合溶媒も用いることができる。この中で、少なくともプロピレンカーボネートとエチレンカーボネートいずれかを有することが好ましい。   Next, the solvent of the electrolytic solution composed of a non-aqueous solution containing lithium ions is, for example, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, γ-butyl lactone, acetonitrile, dimethoxyethane, tetrahydrofuran. , Dioxolane, methylene chloride, sulfolane and the like. Furthermore, a mixed solvent obtained by mixing two or more of these solvents can also be used. Among these, it is preferable to have at least either propylene carbonate or ethylene carbonate.

また、上記溶媒に溶解させる電解質は、電離してリチウムイオンを生成するものであれば良く、例えば、LiI、LiClO4、LiAsF6、LiBF4、LiPF6等が挙げられる。これらの溶質は、上記溶媒中に0.5mol/L以上とすることが好ましく、0.5〜1.5mol/Lの範囲内とすることが更に好ましい。 The electrolyte dissolved in the solvent may be any one that ionizes to generate lithium ions, and examples thereof include LiI, LiClO 4 , LiAsF 6 , LiBF 4 , and LiPF 6 . These solutes are preferably 0.5 mol / L or more in the solvent, and more preferably in the range of 0.5 to 1.5 mol / L.

正極集電体にはアルミニウム、ステンレス等を用いることができる。正極の低抵抗化かつ低コスト化には、一般的にアルミ電解コンデンサや電気二重層キャパシタに用いられているアルミエッチング箔を使用することが好ましい。アルミエッチング箔は、アルミをエッチング処理することで比表面積を増やしているため、正極の活物質層との接触面積が増えて抵抗は低減し、出力特性は向上する。また、汎用品であることから低コストが期待できる。アルミエッチング箔のエッチング処理はいずれのものでも使用できる。   Aluminum, stainless steel, or the like can be used for the positive electrode current collector. In order to reduce the resistance and cost of the positive electrode, it is preferable to use an aluminum etching foil generally used for an aluminum electrolytic capacitor or an electric double layer capacitor. Since the aluminum etching foil increases the specific surface area by etching aluminum, the contact area with the active material layer of the positive electrode is increased, the resistance is reduced, and the output characteristics are improved. Moreover, since it is a general-purpose product, low cost can be expected. Any etching process can be used for the aluminum etching foil.

正極集電体の厚みは、薄い方が好ましく、10〜40μmの厚みが最も好ましい。10μmより薄くなると電極の塗工工程で作業性が低下し、電極を作製できない。また、40μmより厚くなると、電極ユニットあたりの集電体体積が大きくなり、エネルギー密度が低下する。そのため、低抵抗かつ作業性のよい10〜40μmの厚みが望ましい。   The thickness of the positive electrode current collector is preferably thin, and most preferably 10 to 40 μm. If the thickness is less than 10 μm, workability deteriorates in the electrode coating process, and the electrode cannot be produced. Moreover, when it becomes thicker than 40 micrometers, the collector volume per electrode unit will become large and an energy density will fall. Therefore, a thickness of 10 to 40 μm with low resistance and good workability is desirable.

正極の分極性電極層は主として炭素材料で構成され、フェノール樹脂系活性炭、ヤシガラ系活性炭、石油コークス系活性炭やポリアセンなどを用いることができるが、大容量の電気二重層が得られることからフェノール樹脂系活性炭を用いることが好ましい。また、炭素材料としてこれらの活性炭を用いる場合は、平均粒径が20μm以下で、比表面積が600〜3000m2/gの活性炭を用いることが好ましい。 The polarizable electrode layer of the positive electrode is mainly composed of a carbon material, and phenol resin activated carbon, coconut shell activated carbon, petroleum coke activated carbon, polyacene, etc. can be used, but since a large capacity electric double layer is obtained, phenol resin It is preferable to use activated carbon. Moreover, when using these activated carbon as a carbon material, it is preferable to use activated carbon with an average particle diameter of 20 micrometers or less and a specific surface area of 600-3000 m < 2 > / g.

活性炭の賦活処理方法として、水蒸気賦活処理法、アルカリ賦活処理法などがあるが、大容量化にはアルカリ賦活処理した活性炭を用いるのが好ましい。   The activated carbon activation treatment method includes a steam activation treatment method, an alkali activation treatment method, and the like, but it is preferable to use activated carbon subjected to an alkali activation treatment for increasing the capacity.

分極性電極を主体とする正極および負極には、必要により導電助剤やバインダ添加される。導電助剤としては、黒鉛、カーボンブラック、ケッチェンブラック、気相成長カーボンやカーボンナノチューブなどが挙げられ、特にカーボンブラック、黒鉛が好ましい。バインダとしては、例えば、SBR(スチレンブタジエンゴム)等のゴム系バインダやポリ四フッ化エチレン、ポリフッ化ビニリデン等の含フッ素系樹脂、ポリプロピレン、ポリエチレン等の熱可塑性樹脂を用いることができる。   If necessary, a conductive additive or a binder is added to the positive electrode and the negative electrode mainly composed of a polarizable electrode. Examples of the conductive assistant include graphite, carbon black, ketjen black, vapor-grown carbon, and carbon nanotube, and carbon black and graphite are particularly preferable. As the binder, for example, a rubber binder such as SBR (styrene butadiene rubber), a fluorine-containing resin such as polytetrafluoroethylene or polyvinylidene fluoride, or a thermoplastic resin such as polypropylene or polyethylene can be used.

(実施例1、2、3、4)
黒鉛材料88重量部、アセチレンブラック粉体6重量部、SBR5重量部、カルボキシメチルセルロース4重量部、水200重量部を混合して、スラリーを得た。
(Examples 1, 2, 3, 4)
A slurry was obtained by mixing 88 parts by weight of graphite material, 6 parts by weight of acetylene black powder, 5 parts by weight of SBR, 4 parts by weight of carboxymethyl cellulose, and 200 parts by weight of water.

次いで、得られたスラリーを厚さ10μm銅箔の両面に塗布し、乾燥後プレスして、厚さ50μmの負極を得た。   Next, the obtained slurry was applied to both sides of a 10 μm thick copper foil, dried and pressed to obtain a negative electrode having a thickness of 50 μm.

比表面積2000m2/gのアルカリ賦活活性炭92重量部、黒鉛8重量部、SBR3重量部、カルボキシメチルセルロース3重量部、水200重量部を混合したものを、厚み20μmのアルミ箔の両面に塗布し、乾燥後プレスして、厚さ80μmの正極を得た。 A mixture of 92 parts by weight of alkali activated carbon having a specific surface area of 2000 m 2 / g, 8 parts by weight of graphite, 3 parts by weight of SBR, 3 parts by weight of carboxymethyl cellulose and 200 parts by weight of water was applied to both sides of an aluminum foil having a thickness of 20 μm. After drying, pressing was performed to obtain a positive electrode having a thickness of 80 μm.

上記で得られた電極を、その活物質が塗布されている部分の電極面積が6cm2となるように、正極を2枚、負極を3枚切り出した。 Two positive electrodes and three negative electrodes were cut out from the electrode obtained above so that the electrode area of the portion where the active material was applied was 6 cm 2 .

次いで、負極と正極の間に厚さ30μmのセルロース系セパレータ(日本高度紙工業製)を介して、負極/正極/負極の順で、積層して、電極ユニットを作製した。   Subsequently, a negative electrode / positive electrode / negative electrode were laminated in this order via a cellulose separator (manufactured by Nippon Kogyo Paper Industries Co., Ltd.) having a thickness of 30 μm between the negative electrode and the positive electrode to produce an electrode unit.

作製した電極ユニットは、真空乾燥機で130℃、6時間減圧処理した後、アルミラミネートフィルムで形成した容器に入れ、電極ユニット外側に、リチウム金属を負極に対向させて配置させ、エチレンカーボネートとプロピレンカーボネートを1対1の割合で混合した混合溶媒に、1mol/LのLiPF6を溶かした非水電解液を注入し密閉し、蓄電デバイスを作製した。 The produced electrode unit was vacuum-treated at 130 ° C. for 6 hours in a vacuum dryer, then placed in a container formed of an aluminum laminate film, and placed outside the electrode unit with lithium metal facing the negative electrode, ethylene carbonate and propylene A nonaqueous electrolytic solution in which 1 mol / L LiPF 6 was dissolved was injected into a mixed solvent in which carbonate was mixed at a ratio of 1: 1, and sealed to produce an electricity storage device.

作製した蓄電デバイスは、リチウム金属から負極に所定の負極電位まで1時間定電圧放電してリチウムイオンをドープし、負極の電位を2mV(実施例1)、20mV(実施例2)、80mV(実施例3)、120mV(実施例4)に調整した。   The produced electricity storage device was subjected to constant voltage discharge from lithium metal to the negative electrode to a predetermined negative electrode potential for 1 hour to dope lithium ions, and the negative electrode potential was 2 mV (Example 1), 20 mV (Example 2), 80 mV (implementation). Example 3), adjusted to 120 mV (Example 4).

上記の状態のまま、正極を対極にしてセルのESRを測定し、さらにインピーダンスを測定して電荷移動抵抗を算出した。なお、ESRはLCメーターを用いて、周波数1kHzの値を測定した。インピーダンスは、周波数20kHz〜0.01Hz、振幅10mVの範囲で測定し、Cole−Cole Plotより電荷移動抵抗を算出した。   In the above state, the ESR of the cell was measured using the positive electrode as a counter electrode, and the impedance was measured to calculate the charge transfer resistance. In addition, ESR measured the value of frequency 1kHz using LC meter. The impedance was measured in a frequency range of 20 kHz to 0.01 Hz and an amplitude of 10 mV, and charge transfer resistance was calculated from Cole-Cole Plot.

(比較例1)
実施例1と同様に蓄電デバイスを作製し、作製した蓄電デバイスは、リチウム金属から負極に所定の負極電位まで1時間定電圧放電してリチウムイオンをドープし、負極の電位を150mVに調整した。
(Comparative Example 1)
An electricity storage device was produced in the same manner as in Example 1, and the produced electricity storage device was subjected to constant voltage discharge from lithium metal to the negative electrode to a predetermined negative electrode potential for 1 hour to dope lithium ions, and the negative electrode potential was adjusted to 150 mV.

上記の状態のまま、正極を対極にしてセルのESRを測定し、さらにインピーダンスを測定して電荷移動抵抗を算出した。実施例と合わせて、測定結果を表1に示す。ここで、負極電位はLi/Li+の値を示し、ESRは1kHzの抵抗を示している。 In the above state, the ESR of the cell was measured using the positive electrode as a counter electrode, and the impedance was measured to calculate the charge transfer resistance. The measurement results are shown in Table 1 together with the examples. Here, the negative electrode potential indicates a value of Li / Li + , and ESR indicates a resistance of 1 kHz.

Figure 2010141065
Figure 2010141065

表1より、負極電位が150mV(Li/Li+)では、他の電位と比べて抵抗は高いことがわかる。また、負極電位120mV以下では、電位による違い小さいことが分かる。 Table 1 shows that when the negative electrode potential is 150 mV (Li / Li + ), the resistance is higher than other potentials. Further, it can be seen that when the negative electrode potential is 120 mV or less, the difference due to the potential is small.

(実施例5,6)
難黒鉛化炭素材料88重量部、アセチレンブラック粉体6重量部、SBR5重量部、カルボキシメチルセルロース4重量部、水200重量部を混合して、スラリーを得た。
(Examples 5 and 6)
A slurry was obtained by mixing 88 parts by weight of a non-graphitizable carbon material, 6 parts by weight of acetylene black powder, 5 parts by weight of SBR, 4 parts by weight of carboxymethyl cellulose, and 200 parts by weight of water.

次いで、得られたスラリーを厚さ10μm銅箔の両面に塗布し、乾燥後プレスして、厚さ50μmの負極を得た。   Next, the obtained slurry was applied to both sides of a 10 μm thick copper foil, dried and pressed to obtain a negative electrode having a thickness of 50 μm.

比表面積2000m2/gのアルカリ賦活活性炭92重量部、黒鉛8重量部、SBR3重量部、カルボキシメチルセルロース3重量部、水200重量部を混合したものを、厚み20μmのアルミ箔の両面に塗布し、乾燥後プレスして、厚さ80μmの正極を得た。 A mixture of 92 parts by weight of alkali activated carbon having a specific surface area of 2000 m 2 / g, 8 parts by weight of graphite, 3 parts by weight of SBR, 3 parts by weight of carboxymethyl cellulose and 200 parts by weight of water was applied to both sides of an aluminum foil having a thickness of 20 μm. After drying, pressing was performed to obtain a positive electrode having a thickness of 80 μm.

上記で得られた電極を、その活物質が塗布されている部分の電極面積が6cm2となるように、正極を2枚、負極を3枚切り出した。 Two positive electrodes and three negative electrodes were cut out from the electrode obtained above so that the electrode area of the portion where the active material was applied was 6 cm 2 .

次いで、負極と正極の間に30μmのセルロース系セパレータ(日本高度紙工業製)を介して、負極/正極/負極の順で、積層して、電極ユニットを作製した。   Subsequently, a negative electrode / positive electrode / negative electrode were laminated in this order via a 30 μm cellulose separator (manufactured by Nippon Kogyo Paper Industries Co., Ltd.) between the negative electrode and the positive electrode to prepare an electrode unit.

作製した電極ユニットは、真空乾燥機で130℃、6時間減圧処理した後、アルミラミネートフィルムで形成した容器に入れ、電極ユニット外側に、リチウム金属を負極に対向させて配置させ、エチレンカーボネートとプロピレンカーボネートを1対1の割合で混合した混合溶媒に、1mol/LのLiPF6を溶かした非水電解液を注入し密閉し、蓄電デバイスを作製した。 The produced electrode unit was vacuum-treated at 130 ° C. for 6 hours in a vacuum dryer, then placed in a container formed of an aluminum laminate film, and placed outside the electrode unit with lithium metal facing the negative electrode, ethylene carbonate and propylene A nonaqueous electrolytic solution in which 1 mol / L LiPF 6 was dissolved was injected into a mixed solvent in which carbonate was mixed at a ratio of 1: 1, and sealed to produce an electricity storage device.

作製した蓄電デバイスは、リチウム金属から負極に所定の負極電位まで1時間定電圧放電してリチウムイオンをドープし、負極の電位を20mV(実施例5)、80mV(実施例6)に調整した。   The produced electricity storage device was subjected to constant voltage discharge from lithium metal to a predetermined negative electrode potential for 1 hour to dope lithium ions, and the negative electrode potential was adjusted to 20 mV (Example 5) and 80 mV (Example 6).

上記の状態のまま、上記の状態のまま、正極を対極にしてセルのESRを測定し、さらにインピーダンスを測定して電荷移動抵抗を算出した。なお、ESRはLCメーターを用いて、周波数1kHzの値を測定した。インピーダンスは、周波数20kHz〜0.01Hz、振幅10mVの範囲で測定し、Cole−Cole Plotより電荷移動抵抗を算出した。   In the above state, in the above state, the cell ESR was measured with the positive electrode as the counter electrode, and the impedance was measured to calculate the charge transfer resistance. In addition, ESR measured the value of frequency 1kHz using LC meter. The impedance was measured in a frequency range of 20 kHz to 0.01 Hz and an amplitude of 10 mV, and charge transfer resistance was calculated from Cole-Cole Plot.

(比較例2)
実施例5と同様に蓄電デバイスを作製し、作製した蓄電デバイスは、リチウム金属から負極に所定の負極電位まで1時間定電圧放電してリチウムイオンをドープし、負極の電位を150mVに調整した。
(Comparative Example 2)
An electricity storage device was produced in the same manner as in Example 5, and the produced electricity storage device was subjected to constant voltage discharge from lithium metal to the negative electrode to a predetermined negative electrode potential for 1 hour to dope lithium ions, and the negative electrode potential was adjusted to 150 mV.

上記の状態のまま、正極を対極にしてセルのESRを測定し、さらにインピーダンスを測定して電荷移動抵抗を算出した。実施例と合わせて、測定結果を表2に示す。   In the above state, the ESR of the cell was measured using the positive electrode as a counter electrode, and the impedance was measured to calculate the charge transfer resistance. The measurement results are shown in Table 2 together with the examples.

Figure 2010141065
Figure 2010141065

表2より、負極材料を変えても、負極電位が150mV(Li/Li+)では、他の電位と比べて抵抗は高いことがわかる。また、負極電位80mV以下では、電位による違いが小さいことが分かる。 Table 2 shows that even when the negative electrode material is changed, the resistance is higher than the other potentials at a negative electrode potential of 150 mV (Li / Li + ). Further, it can be seen that the difference due to the potential is small when the negative electrode potential is 80 mV or less.

本発明の蓄電デバイスの断面図。Sectional drawing of the electrical storage device of this invention.

符号の説明Explanation of symbols

1 正極
2 負極
3 セパレータ
4 正極集電体
5 負極集電体
6 リチウム金属
7 電解液
DESCRIPTION OF SYMBOLS 1 Positive electrode 2 Negative electrode 3 Separator 4 Positive electrode collector 5 Negative electrode collector 6 Lithium metal 7 Electrolyte

Claims (6)

分極性電極を主体とする正極と、リチウムを可逆的にドープ可能で電位をあらかじめ2〜120mV(Li/Li+)に調整した炭素材料を主体とする負極とをセパレータを介して交互に積層し、電解液にリチウムイオンを含有する非水系の溶液を使用したことを特徴とする蓄電デバイス。 A positive electrode mainly composed of a polarizable electrode and a negative electrode mainly composed of a carbon material which can be reversibly doped with lithium and whose potential is previously adjusted to 2 to 120 mV (Li / Li + ) are alternately laminated via separators. An electricity storage device using a non-aqueous solution containing lithium ions as an electrolyte. 前記負極は、負極面に対向して配置されたリチウム供給源からリチウムをドープさせたことを特徴とする請求項1に記載の蓄電デバイス。   The electricity storage device according to claim 1, wherein the negative electrode is doped with lithium from a lithium supply source disposed to face the negative electrode surface. 前記負極は、集電体に箔を用いたことを特徴する請求項1または2に記載の蓄電デバイス。   The electricity storage device according to claim 1, wherein the negative electrode uses a foil as a current collector. 前記負極は、難黒鉛化炭素材料あるいは黒鉛材料を主成分とすることを特徴とする請求項1から3のいずれか1項に記載の蓄電デバイス。   The electric storage device according to any one of claims 1 to 3, wherein the negative electrode includes a non-graphitizable carbon material or a graphite material as a main component. 前記非水系の溶液は、少なくともプロピレンカーボネートまたはエチレンカーボネートを含むことを特徴とする請求項1から4のいずれか1項に記載の蓄電デバイス。   5. The electricity storage device according to claim 1, wherein the non-aqueous solution contains at least propylene carbonate or ethylene carbonate. 前記正極は、活性炭を主成分とする分極性電極であることを特徴とする請求項1から5のいずれか1項に記載の蓄電デバイス。   The electricity storage device according to any one of claims 1 to 5, wherein the positive electrode is a polarizable electrode mainly composed of activated carbon.
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102013336A (en) * 2010-09-16 2011-04-13 南京双登科技发展研究院有限公司 Asymmetrical super capacitor
JP2012195563A (en) * 2011-02-28 2012-10-11 Jm Energy Corp Lithium ion capacitor
JPWO2015162885A1 (en) * 2014-04-25 2017-04-13 株式会社Gsユアサ Nonaqueous electrolyte secondary battery

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102013336A (en) * 2010-09-16 2011-04-13 南京双登科技发展研究院有限公司 Asymmetrical super capacitor
JP2012195563A (en) * 2011-02-28 2012-10-11 Jm Energy Corp Lithium ion capacitor
JPWO2015162885A1 (en) * 2014-04-25 2017-04-13 株式会社Gsユアサ Nonaqueous electrolyte secondary battery
JP2020188017A (en) * 2014-04-25 2020-11-19 株式会社Gsユアサ Lithium ion secondary battery, battery pack, power storage device, and automobile
JP7021690B2 (en) 2014-04-25 2022-02-17 株式会社Gsユアサ Lithium-ion secondary batteries, assembled batteries, power storage devices and automobiles

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