JP2007329033A - Energy storage device - Google Patents

Energy storage device Download PDF

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JP2007329033A
JP2007329033A JP2006159736A JP2006159736A JP2007329033A JP 2007329033 A JP2007329033 A JP 2007329033A JP 2006159736 A JP2006159736 A JP 2006159736A JP 2006159736 A JP2006159736 A JP 2006159736A JP 2007329033 A JP2007329033 A JP 2007329033A
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energy storage
storage device
lithium ions
negative electrode
carbonaceous material
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Shigetaka Tsubouchi
繁貴 坪内
Juichi Arai
寿一 新井
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Showa Denko Materials Co Ltd
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Hitachi Chemical Co Ltd
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Priority to JP2006159736A priority Critical patent/JP2007329033A/en
Priority to PCT/JP2007/059857 priority patent/WO2007141996A1/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/30—Electrodes characterised by their material
    • H01G11/32—Carbon-based
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries

Abstract

<P>PROBLEM TO BE SOLVED: To provide an energy storage device high in capacity and low in capacity drop when high voltage is applied for long hours. <P>SOLUTION: The energy storage device is composed of a positive electrode mainly comprising activated carbon, a negative electrode mainly comprising a compound formed by absorbing lithium ions equivalent to 75% or more of the total absorbable capacity of a carbonaceous material in the carbonaceous material capable of absorbing and releasing lithium ions, and an electrolyte containing a lithium salt and a nonaqueous solvent. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、バックアップ電源等として用いられるエネルギー貯蔵デバイスに関する。   The present invention relates to an energy storage device used as a backup power source or the like.

エネルギー貯蔵デバイスは大別して、二次電池、電気二重層キャパシタの二つに分けられる。特に大電流で充放電可能な電気二重層キャパシタは電気自動車の動力電源やブレーキ回生、瞬停用バックアップ電源、また負荷平準や無停電電源装置等の用途に有望である。この電気二重層キャパシタは正負両極ともに非ファラデー的な反応機構を有する活性炭を主体とする分極性電極からなるため、ファラデー的な反応機構により充放電する電極からなるリチウム二次電池と比べて、急速充放電が可能である。また、サイクル特性および電圧印加時の耐久性が高いという長所を有する。一方、電気二重層キャパシタの電極は正負両極ともに活性炭からなるため、リチウム二次電池に比べてエネルギー密度が低く、耐電圧が小さいという短所がある。   Energy storage devices are roughly divided into two types: secondary batteries and electric double layer capacitors. In particular, electric double layer capacitors that can be charged / discharged with a large current are promising for applications such as power sources for electric vehicles, brake regeneration, backup power sources for momentary power interruptions, load leveling and uninterruptible power supplies. Since this electric double layer capacitor consists of a polarizable electrode mainly composed of activated carbon having a non-Faraday reaction mechanism for both positive and negative electrodes, it is faster than a lithium secondary battery that is charged and discharged by a Faraday reaction mechanism. Charging / discharging is possible. In addition, the cycle characteristics and the durability during voltage application are high. On the other hand, since the electrodes of the electric double layer capacitor are made of activated carbon for both positive and negative electrodes, the energy density is lower than that of the lithium secondary battery, and the withstand voltage is low.

電気二重層キャパシタの耐電圧は水系電解液を有するものでは水の分解電圧で決定されるため１．２Ｖであり、有機系電解液を有するものでも２．５〜３．３Ｖ程度である。電気二重層キャパシタのセルの静電容量Ｃｔは１／Ｃｔ＝１／Ｃａ＋１／Ｃｃ（Ｃａ：負極の静電容量、Ｃｃ：正極の静電容量）で表され、正負両極とも活性炭を主体とする場合、正極と負極の静電容量がほぼ等しく（Ｃａ＝Ｃｃ＝Ｃ）、セルの静電容量はＣｔ＝Ｃ／２となり、セルエネルギーＥはＥ＝（１／２）ＣｔＶ２＝（１／４）ＣＶ２（Ｖ：耐電圧）となる。従って、水系電解液に比べ耐電圧の高い有機系電解液を用いる電気二重層キャパシタのほうが高エネルギーである。しかしながら、有機系電解液を有する電気二重層キャパシタでもそのエネルギー密度は二次電池には及ばない。 The withstand voltage of the electric double layer capacitor is 1.2 V because it is determined by the decomposition voltage of water in the case of having an aqueous electrolyte, and is about 2.5 to 3.3 V even in the case of having an organic electrolyte. The capacitance C t of the electric double layer capacitor cell is expressed by 1 / C t = 1 / C a + 1 / C c (C a : capacitance of the negative electrode, C c : capacitance of the positive electrode). When both electrodes are mainly composed of activated carbon, the positive and negative electrodes have substantially the same capacitance (C a = C c = C), the cell has a capacitance C t = C / 2, and the cell energy E is E = ( 1/2) C t V 2 = (1/4) CV 2 (V: withstand voltage). Therefore, the electric double layer capacitor using the organic electrolyte having a higher withstand voltage than the aqueous electrolyte has higher energy. However, even an electric double layer capacitor having an organic electrolyte has an energy density that is less than that of a secondary battery.

近年、特許文献１に開示されているように、活性炭を主体とする電極を正極とし、Ｘ線回折における［００２］面の面間隔が０．３３８〜０．３５６ｎｍであるファラデー的な反応機構を示す炭素材料に、予めリチウムイオンを吸蔵させた電極を負極とした上限３．０Ｖの二次電源が提案されている。   In recent years, as disclosed in Patent Document 1, a Faraday-like reaction mechanism in which an electrode mainly composed of activated carbon is used as a positive electrode and the [002] plane spacing in X-ray diffraction is 0.338 to 0.356 nm. A secondary power supply with an upper limit of 3.0 V has been proposed in which an electrode in which lithium ions are previously occluded in the carbon material shown is used as a negative electrode.

また、特許文献１で提案される二次電源は負極容量が正極容量より十分に大きいので、このキャパシタのセルの静電容量は正極の静電容量のみで表され１／Ｃｔ＝１／Ｃａ＋１／Ｃｃ≒１／Ｃｃとなり、Ｃｃ＝Ｃとなる。この際、セルエネルギーＥはＥ＝（１／２）ＣｔＶ２＝（１／２）ＣＶ２となり、電気二重層キャパシタよりセルエネルギーを２倍向上させることができる。また、特許文献２、３には、リチウムイオンを吸蔵、脱離しうる炭素材料に予め化学的方法又は電気化学的方法でリチウムイオンを吸蔵させた炭素材料を負極に用いる電池が提案されている。セルエネルギーＥは耐電圧Ｖの二乗に比例するため、Ｖを上げることでセルエネルギーＥを大幅に増加させる事ができる。 Further, since the secondary power source proposed in Patent Document 1 has a negative electrode capacity sufficiently larger than the positive electrode capacity, the capacitance of the cell of this capacitor is expressed only by the positive electrode capacitance, and 1 / C t = 1 / C. a + 1 / C c ≒ 1 / C c , and becomes a C c = C. At this time, the cell energy E becomes E = (1/2) C t V 2 = (1/2) CV 2 , and the cell energy can be improved twice as compared with the electric double layer capacitor. Patent Documents 2 and 3 propose a battery using, as a negative electrode, a carbon material in which lithium ions are occluded in advance by a chemical method or an electrochemical method in a carbon material that can occlude and desorb lithium ions. Since the cell energy E is proportional to the square of the withstand voltage V, increasing the V can greatly increase the cell energy E.

また、特許文献４には、正極を活性炭とし、負極が特殊な炭素材料である非水リチウム電池が開示されている。   Patent Document 4 discloses a non-aqueous lithium battery in which the positive electrode is activated carbon and the negative electrode is a special carbon material.

特開昭６４−１４８８２号公報JP-A 64-14882 特開平８−１０７０４８号公報Japanese Patent Laid-Open No. 8-1007048 特開平９−５５３４２号公報JP-A-9-55342 特開平１１−２６０２４号公報JP-A-11-26024

ＵＰＳ等のバックアップ電源では常に満充電の状態にしておく必要があり、デバイスは常に高電圧印加状態で置かれることになる。しかしながら、活性炭を主体とする正極と、リチウムイオンを吸蔵、脱離しうる炭素質材料に予めリチウムイオンを吸蔵させた材料を主体とする負極と、Ｌｉ塩と非水溶媒を含む電解液とからなるエネルギー貯蔵デバイスにおいて、予めリチウムイオンを吸蔵させる量を規定しなければ容量低下が起こる。   A backup power source such as a UPS must always be in a fully charged state, and the device is always placed in a high voltage application state. However, it consists of a positive electrode mainly composed of activated carbon, a negative electrode mainly composed of a material in which lithium ions are previously occluded in a carbonaceous material capable of occluding and desorbing lithium ions, and an electrolyte containing a Li salt and a nonaqueous solvent. In the energy storage device, capacity reduction occurs unless the amount of lithium ions stored in advance is specified.

本発明の課題は、高容量でかつ長時間の３．８Ｖ以上の高電圧印加において容量減少が少ないエネルギー貯蔵デバイスを提供することである。   An object of the present invention is to provide an energy storage device that has a high capacity and has a small capacity reduction when a high voltage of 3.8 V or more is applied for a long time.

本発明の課題解決手段は、活性炭を主体とする正極と、リチウムイオンを吸蔵、脱離し得る炭素質材料に予めリチウムイオンをその炭素質材料が吸蔵し得る全容量の７５％以上に相当するリチウムイオンを吸蔵させた化合物を主体とする負極と、リチウム塩と非水溶媒を含む電解液を備えたエネルギー貯蔵デバイスである。   The problem-solving means of the present invention includes a positive electrode mainly composed of activated carbon, and lithium corresponding to 75% or more of the total capacity in which the carbonaceous material can previously store lithium ions in a carbonaceous material that can store and desorb lithium ions. An energy storage device comprising a negative electrode mainly composed of a compound having occluded ions, and an electrolytic solution containing a lithium salt and a non-aqueous solvent.

本発明によれば、高容量でかつ長時間の３．８Ｖ以上の高電圧印加において容量減少が少ないエネルギー貯蔵デバイスが提供される。   ADVANTAGE OF THE INVENTION According to this invention, the energy storage device with a small capacity | capacitance reduction with a high capacity | capacitance and long time high voltage application of 3.8V or more is provided.

本発明において、主体とは、電極合剤を構成する各部材の中で最も重量分率が多いものと定義する。正極の活性炭、負極の炭素質材料は電極合剤中の重量分率で５０％以上を占めるのが好ましく、最も好ましくは８０％以上である。
本発明において、全容量とは、Ｌｉ金属を負極、エネルギー貯蔵デバイスにおいて負極として用いる炭素材料を正極とし、定電流０．５ｍＡ／１５ｍｍΦ、定電圧０Ｖでの充電条件において、電流値が０．０２ｍＡ／１５ｍｍΦ（定電流値の２５分の１）に減衰した時点を充電終了とし求めた充電容量（ｍＡｈ／ｇ）である。 In the present invention, the main body is defined as one having the largest weight fraction among the members constituting the electrode mixture. The activated carbon of the positive electrode and the carbonaceous material of the negative electrode preferably occupy 50% or more by weight fraction in the electrode mixture, and most preferably 80% or more.
In the present invention, the total capacity means that Li metal is used as a negative electrode, a carbon material used as a negative electrode in an energy storage device is used as a positive electrode, and a current value is 0.02 mA under charging conditions at a constant current of 0.5 mA / 15 mmΦ and a constant voltage of 0 V. / 15 mmΦ (Charge capacity (mAh / g)) obtained when charging is terminated at the time of decay to a constant current value of 1/25.

炭素質材料固有の不可逆容量による可逆的に使用可能なリチウム量の減少を考慮し、炭素質材料の種類によらずリチウムイオンの吸蔵量は上記全容量の７５〜１００％であることが好ましく、特に９０％以上が好ましい。この吸蔵量は、実質的に全容量の１００％であることが最も望ましいが、実際に１００％であるか、それに近い値であるかを定量的に決定することは困難である。従って、リチウムイオンの吸蔵・充電に当たって、エネルギー貯蔵デバイスに不利な現象が起こらない範囲で、十分に飽和するまで吸蔵・充電を行ったときのリチウムイオン吸蔵量が１００％であると定義する。
この不可逆容量による可逆的に使用可能なリチウム量の減少による、長時間（１０００ｈ以上）の充放電サイクル後の負極の電位上昇を抑制するには、３．８Ｖ以上の電圧を２４ｈ以上印加した後の正極電位を自然電位とした時の負極の炭素質材料が吸蔵しているリチウム量は６０％以上であるのが好ましい。 Considering the reduction of reversibly usable lithium amount due to the irreversible capacity inherent to the carbonaceous material, the occlusion amount of lithium ions is preferably 75 to 100% of the total capacity regardless of the type of carbonaceous material, In particular, 90% or more is preferable. It is most desirable that this occlusion amount is substantially 100% of the total capacity, but it is difficult to quantitatively determine whether it is actually 100% or a value close thereto. Therefore, it is defined that the lithium ion occlusion amount is 100% when the occlusion / charge is performed until the lithium ion is fully saturated within a range in which no adverse phenomenon occurs in the energy storage device.
In order to suppress the increase in the potential of the negative electrode after a long (1000 h or longer) charge / discharge cycle due to the decrease in the reversibly usable lithium amount due to this irreversible capacity, after applying a voltage of 3.8 V or higher for 24 hours or longer The amount of lithium occluded by the carbonaceous material of the negative electrode when the positive electrode potential is a natural potential is preferably 60% or more.

また、３．８Ｖ以上の印加電圧での使用に際し容量減少抑制への効果が大きく、４Ｖ以上ではその効果はより大きい。前述のように、セルエネルギーＥは充電電圧の２乗に比例するので、３．８Ｖ以上、特に４Ｖ以上で充電することにより、エネルギー貯蔵デバイスのエネルギー容量を大きくすることができる。最も好ましくは、４．２Ｖ以上で充電することである。   In addition, when used at an applied voltage of 3.8 V or higher, the effect of suppressing the decrease in capacity is great, and at 4 V or higher, the effect is greater. As described above, since the cell energy E is proportional to the square of the charging voltage, the energy capacity of the energy storage device can be increased by charging at 3.8 V or higher, particularly 4 V or higher. Most preferably, charging is performed at 4.2 V or higher.

また、本発明の実施例で用いられたセル構成は、以下のとおりである。
正極：フェノール樹脂原料の水蒸気賦活炭およびアルカリ賦活炭、ヤシ殻原料の水蒸気賦活炭のいずれかを用いた。
負極：黒鉛、易黒鉛性炭素及び難黒鉛性炭素のいずれかを用いた。
電解液：（１）塩：ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＣｌＯ４、ＬｉＮ（Ｃ２Ｆ５ＳＯ２）２のいずれか一種および二種からなる混合塩。
（２）溶媒：溶媒全量に対しエチレンカーボネートを２５〜５０％、エチルメチルカーボネートを０〜７５％含む。溶媒は、電気化学的、熱力学的に安定なものであり、セルの特性（容量、出力）に影響しない分量である。電解液は、３．８Ｖ以上での印加電圧に長時間（例えば２４時間）耐えるものを選択することが好ましい。この特性は、負極材料についても当てはまる。 The cell configuration used in the examples of the present invention is as follows.
Positive electrode: Any one of steam activated carbon and alkali activated charcoal of a phenol resin raw material and steam activated charcoal of a coconut shell raw material was used.
Negative electrode: Any of graphite, graphitizable carbon, and non-graphitizable carbon was used.
Electrolytic solution: (1) Salt: A mixed salt composed of one or two of LiPF 6 , LiBF 4 , LiClO 4 , and LiN (C 2 F 5 SO 2 ) 2 .
(2) Solvent: 25-50% ethylene carbonate and 0-75% ethyl methyl carbonate with respect to the total amount of solvent. The solvent is electrochemically and thermodynamically stable and has an amount that does not affect the cell characteristics (capacity and output). It is preferable to select an electrolytic solution that can withstand an applied voltage of 3.8 V or higher for a long time (for example, 24 hours). This property is also true for the negative electrode material.

活性炭を主体とする正極と、リチウムイオンを吸蔵、脱離しうる炭素質材料に予めリチウムイオンを吸蔵させた材料を主体とする負極及びリチウム塩と非水溶媒を含む電解液とを有するエネルギー貯蔵デバイスにおいて、炭素質材料に吸蔵させたリチウムイオン及び電解液中のリチウムイオンが充電時に負極の不可逆容量として消費されてしまう。そのため可逆的に使用可能なリチウムイオンが減少することで、負極の電位上昇または電解液中のイオン濃度低下による内部抵抗の増加により放電時の容量は低下する。さらには負極の電位上昇に伴う正極の電位上昇が電解液の分解等の副反応を引き起こし、デバイスの機能を低下もしくは停止させる。   Energy storage device having a positive electrode mainly composed of activated carbon, a negative electrode mainly composed of a material in which lithium ions are previously stored in a carbonaceous material capable of storing and desorbing lithium ions, and an electrolyte containing a lithium salt and a non-aqueous solvent In this case, lithium ions occluded in the carbonaceous material and lithium ions in the electrolytic solution are consumed as irreversible capacity of the negative electrode during charging. Therefore, reversibly usable lithium ions decrease, and the capacity during discharge decreases due to an increase in internal resistance due to a potential increase in the negative electrode or a decrease in ion concentration in the electrolyte. Furthermore, the increase in the potential of the positive electrode accompanying the increase in the potential of the negative electrode causes a side reaction such as decomposition of the electrolytic solution, thereby lowering or stopping the function of the device.

この容量低下は、負極の主体となる化合物に、リチウムイオンを吸蔵、脱離し得る炭素質材料に予めリチウムイオンをその炭素質材料が吸蔵し得る全容量の７５％以上に相当するリチウムイオンを吸蔵させる事で抑制できる。吸蔵量は、９０％以上であることが好ましく、最も好ましくは、実質的に１００％である。   This decrease in capacity is caused by occlusion of lithium ions corresponding to 75% or more of the total capacity of the carbonaceous material capable of preliminarily occluding lithium ions in a carbonaceous material capable of occluding and desorbing lithium ions in the main compound of the negative electrode. This can be suppressed. The occlusion amount is preferably 90% or more, and most preferably substantially 100%.

負極の不可逆容量に相当するリチウムイオンが消費されても、可逆的に使用可能なリチウムイオン量が多いほうが負極の電位上昇の抑制、内部抵抗上昇の抑制になる。そのため、リチウムイオンを吸蔵、脱離し得る炭素質材料に予めリチウムイオンをその炭素質材料が吸蔵し得る全容量の実質的に１００％に相当するリチウムイオンを吸蔵させるのが最も望ましい。以下、本発明を実施例により、詳細に説明する。   Even if lithium ions corresponding to the irreversible capacity of the negative electrode are consumed, the higher the amount of lithium ions that can be used reversibly, the higher the potential of the negative electrode and the lower the internal resistance. Therefore, it is most desirable to previously store lithium ions corresponding to substantially 100% of the total capacity in which the carbonaceous material can occlude lithium ions in a carbonaceous material that can occlude and desorb lithium ions. Hereinafter, the present invention will be described in detail by way of examples.

図１は、本発明によるエネルギー貯蔵デバイスの予備充電試験用セルの断面図であって、１はＳＵＳ製のプレスセルであり、２がセパレータ、３と４は負極の集電体で、圧延した厚さ２０μｍの銅箔であり、４の上に５の黒鉛合剤を塗布しプレスしたものが結着されている。６の厚さ１ｍｍのリチウム金属箔と５が２のセパレータを介して向き合って配置されており、２の全てのセパレータに電解液を浸透させている。   FIG. 1 is a cross-sectional view of a precharge test cell for an energy storage device according to the present invention, wherein 1 is a SUS press cell, 2 is a separator, and 3 and 4 are negative electrode current collectors. It is a copper foil having a thickness of 20 μm, and is formed by applying 5 graphite mixture on 4 and pressing it. Six 1 mm thick lithium metal foils and 5 are arranged to face each other with two separators interposed therebetween, and the electrolyte is infiltrated into all the two separators.

前記予備充電試験用セルにおいて黒鉛、スチレンブタジエン共重合体、カルボキシメチルセルロースを加えて混練したものを厚さ２０μｍの圧延加工された銅箔に塗布し、３時間以上乾燥したものを電極シートとし、このシートを１５ｍｍΦの大きさに打ち抜きプレスしたものを負極とした。   In the precharge test cell, graphite, styrene butadiene copolymer and carboxymethyl cellulose were added and kneaded and applied to a rolled copper foil having a thickness of 20 μm and dried for 3 hours or more to obtain an electrode sheet. The sheet was punched and pressed to a size of 15 mmΦ to make a negative electrode.

前記予備充電試験用セルにおいてエチレンカーボネートとエチルメチルカーボネートを１：３の割合で混合した溶媒に、１．５ｍｏｌ／ＬのＬｉＰＦ６を溶解させた溶液を電解液とした。前記予備充電試験用セルにおいて厚さ４０μｍ、空孔率４５％のポリエチレン製のシートをセパレータとした。前記予備充電試験用セルにおいて３の負極の集電体と６のリチウム金属を外部端子で繋ぎ、短絡させ（以下、短絡充電という）、短絡させた時間と放電容量の関係を図２に示した。 A solution in which 1.5 mol / L LiPF 6 was dissolved in a solvent in which ethylene carbonate and ethyl methyl carbonate were mixed at a ratio of 1: 3 in the precharge test cell was used as an electrolytic solution. In the precharge test cell, a polyethylene sheet having a thickness of 40 μm and a porosity of 45% was used as a separator. In the preliminary charging test cell, the negative electrode current collector 3 and the lithium metal 6 are connected by an external terminal and short-circuited (hereinafter referred to as short-circuit charging), and the relationship between the short-circuiting time and the discharge capacity is shown in FIG. .

図２より２時間以降の放電容量は、短絡させた時間に関係なく一定である。つまり、前記予備充電試験用セルにおいて短絡時間が２時間以上では負極の黒鉛に吸蔵し得る全容量に相当するリチウムイオンが黒鉛に吸蔵される事を示している。   From FIG. 2, the discharge capacity after 2 hours is constant regardless of the short-circuit time. That is, when the short-circuit time is 2 hours or longer in the precharge test cell, lithium ions corresponding to the total capacity that can be stored in the graphite of the negative electrode are stored in the graphite.

前記予備充電試験用セルにおいて、負極の集電体３と６のリチウム金属を電流制御の可能な装置につながった外部端子で繋いだ。そして、０．２ｍＡ／１５ｍｍΦの定電流で負極の炭素材料にリチウムイオンを各５０、１００、１５０、２００、２５０、３００、３５０ｍＡｈ／ｇまで充電した時の充電容量及びその後０．４ｍＡ／１５ｍｍΦの定電流で１．５Ｖまで放電した時の放電容量と、ＯＣＶ（Ｏｐｅｎ Ｃｉｒｃｕｉｔ Ｖｏｌｔａｇｅ）との関係を調べ、その結果を図３に示した。なお、上記ＯＣＶは充電後３時間の開回路状態後の電圧ＯＣＶである。上記の充電方法を電流制御充電という。   In the preliminary charging test cell, the negative electrode current collectors 3 and 6 were connected by an external terminal connected to a device capable of current control. And the charging capacity when charging lithium ion to 50, 100, 150, 200, 250, 300, 350 mAh / g to the carbon material of the negative electrode at a constant current of 0.2 mA / 15 mmΦ, and then 0.4 mA / 15 mmΦ The relationship between the discharge capacity when discharged to 1.5 V at a constant current and OCV (Open Circuit Voltage) was examined, and the results are shown in FIG. The OCV is a voltage OCV after an open circuit state for 3 hours after charging. The above charging method is called current control charging.

以上述べた短絡充電、もしくは電流制御充電により負極の炭素質材料に予めリチウムイオンを吸蔵させる方法を総称して以下、予備充電方法という。   The above-described methods for preliminarily occluding lithium ions in the carbonaceous material of the negative electrode by short-circuit charging or current-controlled charging are collectively referred to as pre-charging methods.

図３より各放電容量から充電容量を見積もる事ができ、充電後３時間の開回路状態後のＯＣＶから充電容量および放電容量を見積もる事ができる。さらに図２および図３より電流の制御できない起電力充電において、リチウムイオンの吸蔵量を見積もる事ができる検量線として使用できる。   From FIG. 3, the charge capacity can be estimated from each discharge capacity, and the charge capacity and discharge capacity can be estimated from the OCV after the open circuit state for 3 hours after the charge. Further, in the electromotive force charging in which the current cannot be controlled from FIGS. 2 and 3, it can be used as a calibration curve capable of estimating the amount of occlusion of lithium ions.

また負極の炭素材料として、負極の炭素質材料が天然黒鉛、人造黒鉛、黒鉛化メソカーボン小球体、黒鉛ウィスカ、黒鉛化炭素繊維、気相成長炭素、石油コークス、石炭コークス、ピッチコークス等を熱処理した易黒鉛化性炭素材料、フルフリルアルコール樹脂、ノボラック樹脂、フェノール樹脂等を熱処理した難黒鉛性炭素材料、アモルファスカーボンから選ばれる１種以上があげられる。炭素質材料には炭素質材料固有の充電量とＯＣＶの関係があり、負極として用いる炭素質材料を特定し同様の検量線を作る事でＯＣＶから充電量を見積もる事が可能である。   As the carbon material for the negative electrode, the carbonaceous material for the negative electrode is heat-treated natural graphite, artificial graphite, graphitized mesocarbon spherules, graphite whiskers, graphitized carbon fiber, vapor-grown carbon, petroleum coke, coal coke, pitch coke, etc. One or more kinds selected from the graphitizable carbon material, the furfuryl alcohol resin, the novolak resin, the non-graphitizable carbon material obtained by heat treatment of the phenol resin, and the amorphous carbon. The carbonaceous material has a relationship between the charge amount inherent to the carbonaceous material and the OCV, and it is possible to estimate the charge amount from the OCV by specifying the carbonaceous material used as the negative electrode and creating a similar calibration curve.

本実施使用の炭素質材料の検量線より短絡時間と放電容量の関係を確認し、飽和充電量となる３時間短絡による充電量を炭素質材料の全容量の実質１００％に相当する量と規定した。また前記予備充電試験用セルにおいて充電後３時間の開回路状態後のＯＣＶで０．０８Ｖ以下という条件を満たすものに関しても負極の全容量の実質１００％に相当する量と規定する事ができる。また炭素質材料の全容量に対する予備充電量の割合は、炭素質材料を黒鉛で評価する場合には全容量である３７０ｍＡｈ／ｇを基準とし算出した。   The relationship between the short-circuit time and the discharge capacity is confirmed from the calibration curve of the carbonaceous material used in this embodiment, and the charge amount due to the 3-hour short-circuit that becomes the saturated charge amount is defined as an amount corresponding to substantially 100% of the total capacity of the carbonaceous material. did. Further, regarding the precharge test cell that satisfies the condition of an OCV of 0.08 V or less after an open circuit state for 3 hours after charging, it can be defined as an amount corresponding to substantially 100% of the total capacity of the negative electrode. The ratio of the precharge amount to the total capacity of the carbonaceous material was calculated based on the total capacity of 370 mAh / g when the carbonaceous material was evaluated by graphite.

図４は、本発明によるエネルギー貯蔵デバイスのフロート試験用セルの断面図であって、１はＳＵＳ製のプレスセルであり、２がセパレータ、３と４は負極の集電体で、圧延した厚さ２０μｍの銅箔である。４の上に５の黒鉛合剤を塗布しプレスしたものが結着されており、黒鉛には前記予備充電方法によりリチウムイオンが吸蔵されている。６と７は正極の集電体で、圧延した厚さ２０μｍのアルミニウム箔であり、６が圧延した厚さ２０μｍのアルミニウム箔である。７が電解エッチングした厚さ２０μｍのアルミニウム箔であり、７の上に８の活性炭合剤を塗布しプレスしたものが結着されており、５と８が２のセパレータを介して向き合って配置されている。   FIG. 4 is a cross-sectional view of a float test cell of an energy storage device according to the present invention, wherein 1 is a SUS press cell, 2 is a separator, 3 and 4 are negative electrode current collectors, and a rolled thickness. This is a 20 μm thick copper foil. A material obtained by applying and pressing a graphite mixture of 5 on 4 is bound, and lithium ions are occluded in the graphite by the above-described precharging method. 6 and 7 are positive electrode current collectors, which are rolled aluminum foil with a thickness of 20 μm, and 6 is a rolled aluminum foil with a thickness of 20 μm. 7 is an electrolytically etched aluminum foil having a thickness of 20 μm, and an activated carbon mixture of 8 is applied onto 7 and pressed, and 5 and 8 are arranged facing each other through a separator of 2. ing.

それと背面方向に２のセパレータを介して厚さ１ｍｍのリチウム金属箔９を配置する。２の全てのセパレータに電解液を浸透させている。１〜５は５の黒鉛に前記予備充電方法にてリチウムイオンが吸蔵されている以外、前記予備充電試験用セルと同じ部材である。   In addition, a lithium metal foil 9 having a thickness of 1 mm is arranged through a separator 2 in the back direction. The electrolyte solution is infiltrated into all the separators 2. 1 to 5 are the same members as the precharge test cell, except that lithium ions are occluded in the graphite of 5 by the precharge method.

活性炭粉末、カーボンブラック、ポリビニリデンフルオライドからなる混合物にＮ−メチルピロリドンを加えて混練したものを、厚さ２０μｍのエッチング加工されたアルミニウム箔に塗布し、乾燥したものを電極シートとした。このシートを１５ｍｍΦの大きさに打ち抜いたものを正極とした。   A mixture of activated carbon powder, carbon black and polyvinylidene fluoride added with N-methylpyrrolidone and kneaded was applied to an etched aluminum foil having a thickness of 20 μm, and dried to obtain an electrode sheet. A sheet obtained by punching this sheet into a size of 15 mmΦ was used as a positive electrode.

フロート試験用セルにより２ｍA／１５ｍｍΦの定電流で動作電圧が２ＶからｘＶ（ｘ＝３．８、４．０、４．２）までの充放電サイクルを４サイクル行い、２ｍA／１５ｍｍΦの定電流で２ＶからｘＶまで充電した後、ｘＶの電圧印加条件で２４時間の定電圧充電を行った。次いで、２ｍA／１５ｍｍΦで２Ｖまで放電する充放電サイクル（以下、フロート試験という）を行った。１サイクル目（２４ｈ後）の放電容量に対する各サイクルでの放電容量の割合を容量維持率とし、各時間毎の容量維持率を求めた。   Using the float test cell, charge / discharge cycles from 2V to xV (x = 3.8, 4.0, 4.2) at a constant current of 2 mA / 15 mmΦ were performed for 4 cycles, and a constant current of 2 mA / 15 mmΦ. After charging from 2V to xV, constant voltage charging was performed for 24 hours under the voltage application condition of xV. Subsequently, a charge / discharge cycle (hereinafter referred to as a float test) for discharging to 2 V at 2 mA / 15 mmΦ was performed. The ratio of the discharge capacity in each cycle to the discharge capacity in the first cycle (after 24 hours) was defined as the capacity maintenance rate, and the capacity maintenance rate for each hour was determined.

［比較例１］
電流制御充電において０．２ｍＡ／１５ｍｍΦの定電流で１００ｍＡｈ／ｇまで黒鉛に予備充電した電極を負極とし、フェノール樹脂の水蒸気賦活処理した活性炭の電極を正極とし、フロート試験（ｘ＝４．２）を行なった結果を図５及び表１に示す。
表１は、予備充電量の異なる条件での１２００ｈ後の容量維持率の値を示した表である。 [Comparative Example 1]
Float test (x = 4.2), with the electrode pre-charged to graphite up to 100 mAh / g at a constant current of 0.2 mA / 15 mmΦ in current-controlled charging as the negative electrode, and the activated carbon electrode activated by steam activation of phenol resin as the positive electrode The results of performing are shown in FIG.
Table 1 is a table showing the capacity retention ratio values after 1200 hours under different precharge amounts.

Figure 2007329033
Figure 2007329033

［比較例２］
電流制御充電において０．２ｍＡ／１５ｍｍΦの定電流で２００ｍＡｈ／ｇまで黒鉛に予備充電した電極を負極とし、フェノール樹脂の水蒸気賦活処理した活性炭の電極を正極とし、フロート試験（ｘ＝４．２）を行なった結果を図５及び表１に示す。 [Comparative Example 2]
Float test (x = 4.2), with the electrode pre-charged to graphite up to 200 mAh / g at a constant current of 0.2 mA / 15 mmΦ in the current controlled charging as the negative electrode and the activated carbon electrode activated by steam activation of phenol resin as the positive electrode The results of performing are shown in FIG.

［実施例１］
電流制御充電において０．２ｍＡ／１５ｍｍΦの定電流で３５０ｍＡｈ／ｇまで黒鉛に予備充電した電極を負極とし、フェノール樹脂の水蒸気賦活処理した活性炭の電極を正極とし、フロート試験（ｘ＝４．２）を行なった結果を図５及び表１に示す。 [Example 1]
Float test (x = 4.2) with the electrode pre-charged to graphite up to 350 mAh / g at a constant current of 0.2 mA / 15 mmΦ in the current-controlled charging as the negative electrode and the activated carbon electrode activated by steam activation of phenol resin as the positive electrode The results of performing are shown in FIG.

［実施例２］
短絡充電において３時間短絡させ黒鉛に予備充電した電極を負極とし、フェノール樹脂の水蒸気賦活処理した活性炭の電極を正極とし、フロート試験（ｘ＝４．２）を行なった結果を図５および表１に示す。 [Example 2]
FIG. 5 and Table 1 show the results of a float test (x = 4.2) using the electrode short-circuited for 3 hours and preliminarily charged with graphite as the negative electrode, and the activated carbon electrode subjected to steam activation of phenol resin as the positive electrode. Shown in

表１より、実施例１、２のデバイスは、比較例１、２のデバイスよりも、フロート試験における１２００ｈ後の容量維持率が６０％以上も高いことが明らかである。
（１）比較例１、２のエネルギー貯蔵デバイス；予備充電量が、負極の炭素質材料である黒鉛が吸蔵し得る全容量の７５％未満の容量に相当する量である負極を用いた。
（２）実施例１、２のエネルギー貯蔵デバイス；予備充電量が負極の炭素質材料である黒鉛が吸蔵し得る全容量の７５％以上の容量に相当する量である負極を用いた。 From Table 1, it is apparent that the devices of Examples 1 and 2 have a capacity retention rate after 1200 h in the float test of 60% or more higher than the devices of Comparative Examples 1 and 2.
(1) Energy storage device of Comparative Examples 1 and 2 A negative electrode whose precharge amount corresponds to a capacity of less than 75% of the total capacity that can be occluded by graphite, which is a carbonaceous material of the negative electrode, was used.
(2) Energy storage device of Examples 1 and 2: A negative electrode having a precharge amount corresponding to a capacity of 75% or more of the total capacity that can be occluded by graphite which is a carbonaceous material of the negative electrode was used.

［実施例３］
短絡充電において３時間短絡させ黒鉛に予備充電した電極を負極とし、フェノール樹脂の水蒸気賦活処理した活性炭の電極を正極とし、フロート試験（ｘ＝４．０）を行なった結果を図６及び表２に示す。表２は印加電位の異なる条件での６００ｈ後の容量維持率の値を示した表である。 [Example 3]
FIG. 6 and Table 2 show the results of a float test (x = 4.0) using the electrode which was short-circuited for 3 hours and precharged with graphite as the negative electrode and the activated carbon electrode subjected to the steam activation of phenol resin as the positive electrode. Shown in Table 2 is a table showing capacity retention rates after 600 hours under different applied potentials.

Figure 2007329033
Figure 2007329033

［実施例４］
短絡充電において３時間短絡させ黒鉛に予備充電した電極を負極とし、フェノール樹脂の水蒸気賦活処理した活性炭の電極を正極とし、フロート試験（ｘ＝３．８）を行なった結果を図６及び表２に示す。 [Example 4]
FIG. 6 and Table 2 show the results of a float test (x = 3.8) in which the electrode short-circuited for 3 hours and preliminarily charged with graphite was used as the negative electrode and the activated carbon electrode subjected to the steam activation treatment of the phenol resin was used as the positive electrode. Shown in

実施例２〜４に示すように６００ｈ後の容量維持率において、４．２Ｖまでの電圧においては充電電圧に関係なく、容量減少はなくなることが確認された。実施例３、４ともに６００ｈにおいても容量低下が全く見られず、実施例２に比べ印加電圧が低い条件である事から、１０００ｈ以上にわたって容量を維持することができることはもちろん、１２００ｈ以上にわたって容量を維持することができると予測できる。これらの実施例では、負極の主体となる化合物に、リチウムイオンを吸蔵、脱離し得る炭素質材料に予めリチウムイオンを、その炭素質材料が吸蔵し得る全容量に相当するリチウムイオンを吸蔵させた化合物を主体とする負極を用いた。   As shown in Examples 2 to 4, it was confirmed that in the capacity maintenance rate after 600 hours, the capacity decrease was eliminated at the voltage up to 4.2 V regardless of the charging voltage. In Examples 3 and 4, there is no reduction in capacity even at 600 h, and the applied voltage is lower than that in Example 2. Therefore, the capacity can be maintained for 1000 h or more, and the capacity is increased for 1200 h or more. It can be predicted that it can be maintained. In these examples, the main compound of the negative electrode was preliminarily occluded with lithium ions corresponding to the total capacity that can be occluded by the carbonaceous material, in which lithium ions were occluded and desorbed. A negative electrode mainly composed of a compound was used.

［実施例５］
短絡充電において３時間短絡させ黒鉛に予備充電した電極を負極とし、フェノール樹脂のアルカリ賦活処理した活性炭の電極を正極とし、フロート試験（ｘ＝４．２）を行なった結果を図７及び表３に示す。表３は、正極の活性炭種の異なる条件での１０００ｈ後の容量維持率の値を示した表である。 [Example 5]
FIG. 7 and Table 3 show the results of a float test (x = 4.2) using the electrode short-circuited for 3 hours and preliminarily charged with graphite as the negative electrode and the activated carbon electrode activated with the phenol resin alkali activated as the positive electrode. Shown in Table 3 is a table showing the capacity retention rate values after 1000 hours under different conditions of the activated carbon type of the positive electrode.

Figure 2007329033
Figure 2007329033

［実施例６］
短絡充電において３時間短絡させ黒鉛に予備充電した電極を負極とし、ヤシ殻の水蒸気賦活処理した活性炭の電極を正極とし、フロート試験（ｘ＝４．２）を行なった結果を図７及び表３に示す。 [Example 6]
FIG. 7 and Table 3 show the results of a float test (x = 4.2) using the electrode which was short-circuited for 3 hours and pre-charged with graphite as the negative electrode, and the activated carbon electrode of the coconut shell subjected to steam activation was used as the positive electrode. Shown in

図７及び表３の結果から活性炭の原材料、賦活処理方法によらず、容量維持率の低下が抑制される事が確認された。   From the results of FIG. 7 and Table 3, it was confirmed that the decrease in the capacity retention rate was suppressed regardless of the raw material of activated carbon and the activation treatment method.

［実施例７］
短絡充電において３時間短絡させ黒鉛に予備充電した電極を負極とし、フェノール樹脂の水蒸気賦活処理した活性炭の電極を正極とし、電解液中１．５ＭのＬｉＰＦ６の代わりにＬｉＰＦ６とＬｉＣｌＯ４を９対１の割合で混合した１．５ＭのＬｉ塩を含有した電解液を用いて、フロート試験（ｘ＝４．２）を行なった結果を図８及び表４に示す。表４は、異なるＬｉ塩条件での７２０ｈ後の容量維持率の値を示した表である。 [Example 7]
In the short-circuit charging, an electrode short-circuited for 3 hours and preliminarily charged with graphite is used as a negative electrode, an activated carbon electrode subjected to a phenol resin water vapor activation treatment is used as a positive electrode, and LiPF 6 and LiClO 4 are used in place of 1.5M LiPF 6 in the electrolyte. FIG. 8 and Table 4 show the results of a float test (x = 4.2) using an electrolytic solution containing 1.5 M Li salt mixed at a ratio of 1: 2. Table 4 is a table showing capacity retention rates after 720 h under different Li salt conditions.

Figure 2007329033
Figure 2007329033

［実施例８］
短絡充電において３時間短絡させ黒鉛に予備充電した電極を負極とし、フェノール樹脂の水蒸気賦活処理した活性炭の電極を正極とし、電解液中１．５ＭのＬｉＰＦ６の代わりにＬｉＰＦ６とＬｉＮ（Ｃ２Ｆ５ＳＯ２）２を９対１の割合で混合した１．５ＭのＬｉ塩を含有した電解液を用いて、フロート試験（ｘ＝４．２）を行なった結果を図８及び表４に示す。 [Example 8]
In the short-circuit charging, the electrode short-circuited for 3 hours and pre-charged with graphite is used as the negative electrode, the electrode of activated carbon treated with steam activation of phenol resin is used as the positive electrode, and LiPF 6 and LiN (C 2 are used instead of 1.5M LiPF 6 in the electrolyte. FIG. 8 and Table 4 show the results of a float test (x = 4.2) using an electrolytic solution containing 1.5 M Li salt mixed with F 5 SO 2 ) 2 at a ratio of 9: 1. Show.

［実施例９］
短絡充電において３時間短絡させ黒鉛に予備充電した電極を負極とし、フェノール樹脂の水蒸気賦活処理した活性炭の電極を正極とし、電解液中１．５ＭのＬｉＰＦ６の代わりにＬｉＰＦ６とＬｉＢＦ４を１対１の割合で混合した１．５ＭのＬｉ塩を含有した電解液を用いて、フロート試験（ｘ＝４．２）を行なった結果を図８及び表４に示す。 [Example 9]
In the short-circuit charging, an electrode short-circuited for 3 hours and preliminarily charged with graphite is used as a negative electrode, an activated carbon electrode subjected to steam activation treatment of phenol resin is used as a positive electrode, and LiPF 6 and LiBF 4 are replaced with 1 in place of 1.5M LiPF 6 in the electrolyte. FIG. 8 and Table 4 show the results of a float test (x = 4.2) using an electrolytic solution containing 1.5 M Li salt mixed at a ratio of 1: 2.

実施例２および実施例７〜９の結果よりＬｉＰＦ６の単独塩及び混合塩によらず、容量維持率の低下が抑制される事が確認された。 From the results of Example 2 and Examples 7 to 9, it was confirmed that the decrease in the capacity retention rate was suppressed regardless of the LiPF 6 single salt and mixed salt.

［実施例１０］
短絡充電において３時間短絡させ黒鉛に予備充電した電極を負極とし、フェノール樹脂の水蒸気賦活処理した活性炭の電極を正極とし、電解液中１．５ＭのＬｉＰＦ６の代わりに１．５ＭのＬｉＢＦ４を含有した電解液を用いて、フロート試験（ｘ＝４．２）を行なった結果を図９及び表４に示す。 [Example 10]
In the short-circuit charging, an electrode short-circuited for 3 hours and pre-charged to graphite is used as a negative electrode, an activated carbon electrode subjected to a phenol resin water vapor activation treatment is used as a positive electrode, and 1.5 M LiBF 4 is used instead of 1.5 M LiPF 6 in the electrolyte. The results of a float test (x = 4.2) using the contained electrolyte are shown in FIG.

［実施例１１］
短絡充電において３時間短絡させ黒鉛に予備充電した電極を負極とし、フェノール樹脂の水蒸気賦活処理した活性炭の電極を正極とし、電解液中１．５ＭのＬｉＰＦ６の代わりにＬｉＢＦ４とＬｉＣｌＯ４を９対１の割合で混合した１．５ＭのＬｉ塩を含有した電解液を用いて、フロート試験（ｘ＝４．２）を行なった結果を図９及び表４に示す。 [Example 11]
In the short-circuit charging, an electrode short-circuited for 3 hours and pre-charged to graphite is used as a negative electrode, an electrode of activated carbon treated with steam activation of phenol resin is used as a positive electrode, and LiBF 4 and LiClO 4 are used in place of 1.5M LiPF 6 in the electrolyte. FIG. 9 and Table 4 show the results of a float test (x = 4.2) using an electrolytic solution containing 1.5 M Li salt mixed at a ratio of 1: 2.

［実施例１２］
短絡充電において３時間短絡させ黒鉛に予備充電した電極を負極とし、フェノール樹脂の水蒸気賦活処理した活性炭の電極を正極とし、電解液中１．５ＭのＬｉＰＦ６の代わりにＬｉＢＦ４とＬｉＮ（Ｃ２Ｆ５ＳＯ２）２を９対１の割合で混合した１．５ＭのＬｉ塩を含有した電解液を用いて、フロート試験（ｘ＝４．２）を行なった結果を図９及び表４に示す。 [Example 12]
In the short-circuit charging, an electrode short-circuited for 3 hours and preliminarily charged with graphite is used as a negative electrode, and an electrode of activated carbon treated with steam activation of phenol resin is used as a positive electrode, and LiBF 4 and LiN (C 2 are used instead of 1.5M LiPF 6 in the electrolyte. FIG. 9 and Table 4 show the results of a float test (x = 4.2) using an electrolytic solution containing 1.5 M Li salt mixed with F 5 SO 2 ) 2 at a ratio of 9: 1. Show.

実施例１０〜１２の結果よりＬｉＢＦ４の単独塩及び混合塩によらず、容量維持率の低下が抑制される事が確認された。 From the results of Examples 10 to 12, it was confirmed that the decrease in capacity retention rate was suppressed regardless of the LiBF 4 single salt and mixed salt.

本発明の検討の実施に際しプレスセルでの評価を行なったが、本発明はプレスセル以外の捲回タイプを含む、全ての素子に有用である。そして、本発明の実施例に拠れば、３Ｖ以上、特に３．８Ｖ以上の電圧を印加した状態で長時間の利用が可能であり、容量低下の少ない信頼性の高い、瞬停時等に高容量のエネルギーを供給できるエネルギー蓄電デバイスを提供することができる。   Although evaluation with a press cell was performed in carrying out the study of the present invention, the present invention is useful for all elements including a wound type other than the press cell. According to the embodiment of the present invention, it can be used for a long time with a voltage of 3 V or more, particularly 3.8 V or more applied, and has a high reliability during a momentary power failure or the like with little reduction in capacity. An energy storage device capable of supplying energy of a capacity can be provided.

本発明によるエネルギー貯蔵デバイスの予備充電用セルの断面図。1 is a cross-sectional view of a precharging cell for an energy storage device according to the present invention. 短絡時間における負極の黒鉛へのリチウムイオンの吸蔵量を放電容量との関係で示したグラフである。It is the graph which showed the occlusion amount of the lithium ion to the graphite of the negative electrode in the short circuit time in relation to the discharge capacity. 負極の予備充電容量とその放電容量を、予備充電後休止３時間後のＯＣＶの関係で示したグラフである。It is the graph which showed the preliminary | backup charge capacity of the negative electrode, and its discharge capacity by the relationship of OCV 3 hours after a rest after preliminary charge. 本発明によるエネルギー貯蔵デバイスのフロート試験用セルの断面図。Sectional drawing of the cell for a float test of the energy storage device by this invention. 予備充電量の異なる条件での容量維持率の変化を示したグラフである。It is the graph which showed the change of the capacity | capacitance maintenance factor on the conditions from which a preliminary | backup charge amount differs. 印加電位の異なる条件での容量維持率の変化を示したグラフである。It is the graph which showed the change of the capacity | capacitance maintenance factor on the conditions from which an applied potential differs. 正極の活性炭種の異なる条件での容量維持率の変化を示したグラフである。It is the graph which showed the change of the capacity | capacitance maintenance factor on the conditions from which the activated carbon kind of a positive electrode differs. 異なるＬｉＰＦ６混合塩条件での容量維持率の変化を示したグラフである。It is a graph showing a change in capacity retention rate at different LiPF 6 mixed salt conditions. ＬｉＢＦ４単独塩及び異なるＬｉＢＦ４混合塩条件での容量維持率の変化を示したグラフである。LiBF is a graph showing changes in capacity maintenance ratio at 4 alone salts and different LiBF 4 mixed salt conditions.

符号の説明Explanation of symbols

１…プレスセル、２…セパレータ、３…負極集電箔、４…負極集電箔、５…負極炭素質材料合剤、９…リチウム金属箔。   DESCRIPTION OF SYMBOLS 1 ... Press cell, 2 ... Separator, 3 ... Negative electrode collector foil, 4 ... Negative electrode collector foil, 5 ... Negative electrode carbonaceous material mixture, 9 ... Lithium metal foil.

Claims (9)

活性炭を主体とする正極と、リチウムイオンを吸蔵、脱離し得る炭素質材料に予めリチウムイオンをその炭素質材料が吸蔵し得る全容量の７５〜１００％に相当するリチウムイオンを吸蔵させた化合物を主体とする負極と、リチウム塩と非水溶媒を含む電解液とを有するエネルギー貯蔵デバイス。   A positive electrode mainly composed of activated carbon, and a compound in which lithium ions corresponding to 75 to 100% of the total capacity in which the carbonaceous material can occlude lithium ions are preliminarily stored in a carbonaceous material that can occlude and desorb lithium ions. An energy storage device having a negative electrode as a main component and an electrolyte containing a lithium salt and a non-aqueous solvent. 前記負極は、リチウムイオンを吸蔵、脱離し得る炭素質材料に予めリチウムイオンをその炭素質材料が吸蔵し得る全容量の９０〜１００％に相当するリチウムイオンを吸蔵させた化合物を主体とするものである請求項１記載のエネルギー貯蔵デバイス。   The negative electrode mainly comprises a compound in which lithium ions corresponding to 90 to 100% of the total capacity of the carbonaceous material capable of occluding and desorbing lithium ions are previously stored in a carbonaceous material capable of occluding and desorbing lithium ions. The energy storage device according to claim 1. 前記負極は、リチウムイオンを吸蔵、脱離し得る炭素質材料に予めリチウムイオンをその炭素質材料が吸蔵し得る全容量の実質的に１００％に相当するリチウムイオンを吸蔵させた化合物を主体とするものである請求項１記載のエネルギー貯蔵デバイス。   The negative electrode is mainly composed of a compound in which lithium ions corresponding to substantially 100% of the total capacity in which the carbonaceous material can occlude lithium ions are previously occluded in a carbonaceous material that can occlude and desorb lithium ions. The energy storage device according to claim 1, wherein 前記エネルギー貯蔵デバイスにおいて３．８Ｖ以上の電圧を２４ｈ以上印加した後の正極電位を自然電位とした時の前記負極が、リチウムイオンを吸蔵、脱離し得る炭素質材料にリチウムイオンをその炭素質材料が吸蔵し得る全容量の６０〜１００％に相当するリチウムイオンを吸蔵させた化合物を主体とするものである請求項１記載のエネルギー貯蔵デバイス。   In the energy storage device, when the positive electrode potential after applying a voltage of 3.8 V or more for 24 hours or more is a natural potential, the negative electrode is a carbonaceous material that can occlude and desorb lithium ions. The energy storage device according to claim 1, wherein the energy storage device is mainly composed of a compound that occludes lithium ions corresponding to 60 to 100% of the total capacity that can be occluded. １０００時間以上、３．８Ｖ以上の電圧を印加し続けることができる請求項１記載のエネルギー貯蔵デバイス。   The energy storage device according to claim 1, wherein a voltage of 3.8 V or more can be continuously applied for 1000 hours or more. １０００時間以上、４Ｖ以上の電圧を印加し続けることができる請求項１記載のエネルギー貯蔵デバイス。   The energy storage device according to claim 1, wherein a voltage of 4 V or more can be continuously applied for 1000 hours or more. 請求項１〜６のいずれかに記載のエネルギー貯蔵デバイスにおいて、非水溶媒が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、γ−ブチロラクトン、γ−バレロラクトン、メチルアセテート、エチルアセテート、メチルプロピオネート、テトラヒドロフラン、２−メチルテトラヒドロフラン、１，２−ジメトキシエタン、１−エトキシ−２−メトキシエタン、３−メチルテトラヒドロフラン、１，２−ジオキサン、１，３−ジオキサン、１，４−ジオキサン、１，３−ジオキソラン、２−メチル−１，３−ジオキソラン及び４−メチル−１，３−ジオキソランからなる群から選ばれる１種以上を含む混合溶媒であるエネルギー貯蔵デバイス。   The energy storage device according to any one of claims 1 to 6, wherein the non-aqueous solvent is ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, γ-butyrolactone, γ-valerolactone, methyl acetate. , Ethyl acetate, methyl propionate, tetrahydrofuran, 2-methyltetrahydrofuran, 1,2-dimethoxyethane, 1-ethoxy-2-methoxyethane, 3-methyltetrahydrofuran, 1,2-dioxane, 1,3-dioxane, 1 , 4-dioxane, 1,3-dioxolane, 2-methyl-1,3-dioxolane and energy storage device which is a mixed solvent containing one or more selected from the group consisting of 4-methyl-1,3-dioxolane Su. 請求項１〜６のいずれかに記載のエネルギー貯蔵デバイスにおいて、リチウム塩がＬｉＰＦ６、ＬｉＢＦ４及びＬｉＣｌＯ４、ＬｉＮ（Ｃ２Ｆ５ＳＯ２）２からなる群から選ばれる一種以上からなるエネルギー貯蔵デバイス。 In energy storage device according to claim 1, energy storage lithium salt is composed of LiPF 6, LiBF 4 and LiClO 4, LiN (C 2 F 5 SO 2) one or more selected from the group consisting of 2 device. 請求項１〜６のいずれかに記載のエネルギー貯蔵デバイスにおいて、負極の炭素質材料が天然黒鉛、人造黒鉛、黒鉛化メソカーボン小球体、黒鉛ウィスカ、黒鉛化炭素繊維、気相成長炭素、石油コークス、石炭コークス、ピッチコークスを熱処理した易黒鉛化性炭素材料、フルフリルアルコール樹脂、ノボラック樹脂、フェノール樹脂を熱処理した難黒鉛性炭素材料及びアモルファスカーボンから選ばれる１種以上からなるエネルギー貯蔵デバイス。   The energy storage device according to any one of claims 1 to 6, wherein the carbonaceous material of the negative electrode is natural graphite, artificial graphite, graphitized mesocarbon spherule, graphite whisker, graphitized carbon fiber, vapor grown carbon, petroleum coke. An energy storage device comprising at least one selected from graphitizable carbon materials obtained by heat treating coal coke, pitch coke, furfuryl alcohol resin, novolac resin, non-graphitizable carbon materials obtained by heat treating phenol resin, and amorphous carbon.
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JP2013026505A (en) * 2011-07-22 2013-02-04 Asahi Kasei Corp Nonaqueous lithium type electricity storage element
JP2016162957A (en) * 2015-03-04 2016-09-05 Ｊｍエナジー株式会社 Lithium ion capacitor

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JP2004079321A (en) * 2002-08-16 2004-03-11 Asahi Kasei Electronics Co Ltd Non-aqueous lithium storage element
JP2005228730A (en) * 2004-01-15 2005-08-25 Asahi Kasei Electronics Co Ltd Nonaqueous lithium type storage element
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JP2007180431A (en) * 2005-12-28 2007-07-12 Fuji Heavy Ind Ltd Lithium ion capacitor

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JP2013026505A (en) * 2011-07-22 2013-02-04 Asahi Kasei Corp Nonaqueous lithium type electricity storage element
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