WO2021210284A1 - Lithium ion secondary battery - Google Patents

Lithium ion secondary battery Download PDF

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Publication number
WO2021210284A1
WO2021210284A1 PCT/JP2021/008159 JP2021008159W WO2021210284A1 WO 2021210284 A1 WO2021210284 A1 WO 2021210284A1 JP 2021008159 W JP2021008159 W JP 2021008159W WO 2021210284 A1 WO2021210284 A1 WO 2021210284A1
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negative electrode
electrode
positive electrode
lithium ion
secondary battery
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PCT/JP2021/008159
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French (fr)
Japanese (ja)
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栄二 關
耕平 本蔵
渉太 伊藤
杉政　昌俊
誠之 廣岡
純 川治
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株式会社日立製作所
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H01M10/0585—Construction or manufacture of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to a lithium ion secondary battery.
  • Lithium-ion secondary batteries are one of the non-aqueous electrolyte secondary batteries, and because of their high energy density, they are also used as batteries for portable devices and, in recent years, as batteries for electric vehicles. However, it is known that a lithium ion secondary battery deteriorates with use and the battery capacity decreases.
  • a lithium metal oxide is generally used as an active material for a positive electrode, and a carbon material such as graphite is used as an active material for a negative electrode.
  • the positive electrode and the negative electrode of a lithium ion battery are manufactured by adding a binder, a conductive agent, or the like to a group of minute active material particles to form a slurry, and then applying the mixture to a metal foil.
  • the lithium ions released from the active material of the positive electrode are occluded in the active material of the negative electrode, and at the time of discharging, the lithium ions stored in the active material of the negative electrode are occluded and stored in the active material of the positive electrode.
  • the lithium ions move between the electrodes in this way, a current flows between the electrodes.
  • the battery capacity is reduced due to the electrical isolation of the positive electrode active material, the electrical isolation of the negative electrode active material, the immobilization of lithium ions, and the like.
  • the immobilization of lithium ions includes immobilization in the initial charge / discharge and immobilization by repeating the charge / discharge cycle.
  • Patent Document 1 discloses a technique of joining a third electrode and a negative electrode and pre-doping lithium corresponding to the irreversible capacity of the negative electrode for the purpose of compensating for a decrease in battery capacity due to the irreversible capacity of the SiO negative electrode. There is.
  • An object of the present invention is to provide a lithium ion secondary battery capable of suppressing immobilization of lithium ions and excessive replenishment of lithium ions due to repeated charge / discharge cycles.
  • the lithium ion secondary battery of the present invention is a lithium ion secondary battery having a cell including a positive electrode, a negative electrode, and a third electrode, and the negative electrode is coated with a negative electrode mixture layer on both sides of a negative electrode metal foil. It has a double-sided coated negative electrode and a single-sided coated negative electrode with a negative electrode mixture layer coated on one side of the negative electrode metal foil.
  • the third pole exposes the negative electrode metal foil of the single-sided coated negative electrode. It is characterized in that it is arranged so as to face the surface of the surface.
  • the present invention it is possible to suppress the immobilization of lithium ions and the excessive replenishment of lithium ions due to repeated charge / discharge cycles, improve the recovery efficiency for lithium ion replenishment, thinn the third electrode, and reduce the thickness of the negative electrode.
  • the energy density can be improved by single-sided coating.
  • FIG. 3 is a schematic cross-sectional view of the cell shown in FIG. The perspective view which shows the part of the winding body disassembled.
  • FIG. 1 is a diagram schematically showing a configuration of a lithium ion secondary battery of the present embodiment.
  • the lithium ion secondary battery of the present embodiment is a lithium ion secondary battery with a recovery function that recovers the battery capacity by adding lithium ions when the battery capacity decreases due to the immobilization of lithium ions by repeating the charge / discharge cycle. It is a battery.
  • the lithium ion secondary battery 100 shown in FIG. 1 is a laminated lithium ion secondary battery.
  • the lithium ion secondary battery 100 has a cell 1.
  • the cell 1 is installed inside a container 10 made of a laminated film, and has a structure in which the periphery is filled with an electrolytic solution. That is, the cell 1 is housed inside the container 10 filled with the electrolytic solution.
  • the cell 1 is provided with a positive electrode 21, negative electrodes 22, 23 and a separator 25 laminated and a third pole 24 is provided. It is desirable that the discharge capacity of the negative electrode 22 is larger than the discharge capacity of the positive electrode 21.
  • the negative electrode mixture layer 22b of the negative electrode 22 is wider than the positive electrode mixture layer 21b of the positive electrode 21, and when the negative electrode 22 and the positive electrode 21 are overlapped, the edge of the positive electrode active material coated surface 21b is formed.
  • the end portion of the negative electrode active material coated surface 22b has a size that protrudes more than the portion.
  • FIG. 2 is a schematic cross-sectional view of the cell shown in FIG. 1, and is shown so that the laminated state inside the cell can be understood.
  • Cell 1 is composed of a laminated body in which sheet-shaped electrodes are laminated. That is, as shown in FIG. 2, the cell 1 has a structure in which a positive electrode 21 having a sheet shape, a double-sided coated negative electrode 22, and a single-sided coated negative electrode 23 are alternately arranged and laminated via a separator 25. There is.
  • a pair of third poles 24 are arranged so as to be sandwiched from both sides in the stacking direction.
  • a pair of separators 25 are arranged on both sides in the stacking direction, and the left and right ends of the cell 1 in the drawing are covered with the separators 25.
  • the cell 1 has a positive electrode 21 in which the positive electrode mixture layer 21b is coated on both sides of the positive electrode metal foil 21a, a double-sided coating negative electrode 22 in which the negative electrode mixture layer 22b is coated on both sides of the negative electrode metal foil 22a, and a negative electrode.
  • a single-sided coating negative electrode 23 in which the negative electrode mixture layer 23b is coated on one side of the metal foil 23a, and a third pole 24 in which the mixture layer 24b is coated on both sides of the metal foil 24a are separated between each other. It has a structure in which 25 is laminated.
  • the third pole 24 has the same structure as the positive electrode 21, that is, the positive electrode mixture layer is coated on both sides of the positive electrode metal foil.
  • the positive electrode 21 and the double-sided coated negative electrode 22 are alternately laminated, and the single-sided coated negative electrode 23 is arranged outside the stacking direction of the positive electrode 21 arranged on the outermost side of the laminated body, and the single-sided coated negative electrode 23 is arranged.
  • the third pole 24 is arranged outside the stacking direction of the 23.
  • the negative electrode mixture layer 23b is arranged inside in the lamination direction
  • the negative electrode metal foil 23a is arranged outside in the lamination direction
  • the negative electrode mixture layer 23b faces the positive electrode 21, and the negative electrode metal foil 23a Is arranged to face the third pole 24.
  • the third pole 24 is arranged so as to face the surface of the single-sided coated negative electrode 23 where the negative electrode metal foil 23a is exposed.
  • FIG. 3 is a perspective view showing a part of the wound body in an exploded manner.
  • the cell 1 may be a wound body in which a band-shaped electrode is wound, and the third pole 24 may be installed near the winding axis of the wound body or at the outermost peripheral portion.
  • the strip-shaped positive electrode 21 and the double-sided coated negative electrode 22 are wound in a state of being overlapped with a separator 25 sandwiched between them, and the single-sided coated negative electrode 23 is wound continuously on the double-sided coated negative electrode 22 and the separator is wound on the outside thereof.
  • the third pole 24 may be wound at least one turn or more via the above.
  • the single-sided coating negative electrode 23 has a configuration in which the negative electrode metal foil 23a is arranged so as to face the third pole 24.
  • the wound body for example, only the third pole 24 is wound a plurality of times to form a core of the wound body, and on the outside of the core, a single-sided coating negative electrode 23 is provided via a separator 25. Is wound so that the negative electrode metal foil 23a of the single-sided coating negative electrode 23 faces the core. Then, the double-sided coating negative electrode 22 and the positive electrode 21 may be wound around the outer periphery via a separator 25. In this case, the double-sided coating negative electrode 22 may be formed continuously on the single-sided coating negative electrode 23.
  • the positive electrode 21, the double-sided coated negative electrode 22, the single-sided coated negative electrode 23, and the third pole 24 are each a predetermined metal collecting foil (metal foil) mixed with a predetermined electrode active material, a conductive agent, a binder, and the like. It is made by painting what has been done.
  • the negative electrode metal foil 23a which is an uncoated portion, faces the third pole 24.
  • the active material of the third pole 24 is preferably a material containing a reactive species inside. For example, it is possible to use LiCoO 2, LiNi x Mn y Co z O 2 positive active material, such as, a Li metal as the active material of the third pole 24.
  • the arrangement of the third pole 24 is not limited to this figure, and may be charged or discharged from the positive electrode 21 or the negative electrodes 22 and 23.
  • the potential difference between the negative electrode and the positive electrode is changed using the third electrode.
  • a method of changing the potential difference between the positive electrode and the negative electrode a method of charging only the negative electrode by a predetermined amount using the third electrode and adding lithium ions to the negative electrode, or a method of charging the positive electrode and the negative electrode and then charging the positive electrode with the third electrode.
  • the present invention is not limited to this, and the present invention is not limited to this, and the all-solid-state battery, the semi-solid-state battery, etc., which do not have the separator 25, etc. It is also applicable to.
  • Example 1 In order to prepare the positive electrode mixture layer 21b, LiNi 0.5 Mn 0.2 Co 0.3 was used as the positive electrode active material, a carbon material was used as the positive electrode conductive agent, and polyvinylidene fluoride (PVDF) was used as the positive electrode binder.
  • the mass ratio of the positive electrode active material, the positive electrode conductive agent, and the positive electrode binder is 93: 4: 3, and the positive electrode mixture layer slurry in which these are mixed is adjusted in viscosity with N-methyl-2-pyrrolidone as a dispersion solvent.
  • a 15 ⁇ m aluminum foil (positive electrode current collector) was coated to prepare a positive electrode mixture layer.
  • the coating amount of the positive electrode mixture layer was set to 300 g / m 2 . After the positive electrode after coating was dried at 120 ° C., the density was adjusted by a roll press to adjust the density of the positive electrode mixture layer 21b to 3.0 g / cm 3 .
  • the negative electrode mixture layer 22b graphite was used as the negative electrode active material, a carbon material was used as the negative electrode conductive agent, and styrene-butadiene rubber (SBR) and carboxymethyl cellulose (CMC) were used as the negative electrode binder.
  • SBR styrene-butadiene rubber
  • CMC carboxymethyl cellulose
  • the mass ratio of the negative electrode active material, SBR, and CMC is 98: 1: 1, and the negative electrode mixture layer slurry in which these are mixed is applied to a 10 ⁇ m copper foil (negative electrode current collector) while adjusting the viscosity with water.
  • the work was carried out to prepare a negative electrode mixture layer 22b.
  • the amount of double-sided coating of the negative electrode mixture layer 22b was 190 g / m 2, and two types of coating, single-sided coating and double-sided coating, were produced. After the negative electrode after coating was dried at 100 ° C., the density was adjusted by a roll press to adjust the density of the negative electrode mixture layer 22b to 1.5 g / cm 3 .
  • the third electrode the one having the same configuration as the positive electrode was used.
  • the positive electrode 21, the negative electrode 22, 23 and the third electrode 24 were cut to a predetermined size. At the time of cutting, the electrode tabs 5, 7, and 6 in which the electrode mixture layer was not coated on a part of the electrode current collector were left in the positive electrode 21, the negative electrode 22, 23, and the third electrode 24, respectively.
  • the cut positive electrode 21 and the negative electrode 22 are alternately laminated with a separator 25 sandwiched between them.
  • the outermost negative electrode is a single-sided coated negative electrode 23, and the third electrode 24 is arranged outside the single-sided coated negative electrode 23. Then, it was made to face the third pole 24.
  • the negative electrode metal foil 23a which is an uncoated surface, was arranged so as to face the third pole 24 to form cell 1.
  • the plurality of positive electrode tabs 5, the plurality of negative electrode tabs 7 and the plurality of third electrode tabs 6 of the cell 1 are bundled and connected to the positive electrode terminal, the negative electrode terminal and the third electrode terminal that electrically connect the inside and outside of the lithium ion secondary battery.
  • the bundled electrode tabs were ultrasonically welded, respectively.
  • the capacity of the produced positive electrode 21 is 300 mAh, and the capacity of the negative electrode 22 opposite the positive electrode is 460 mAh.
  • the prepared cell 1 is placed inside the exterior body, the edge of the exterior body is heat-welded and sealed at 175 ° C. for 10 seconds, and the positive electrode terminal and the negative electrode terminal are projected to the outside of the lithium ion secondary battery in an electrically insulated state. I did. In order to provide a liquid injection port, sealing is performed by heat welding except for one side of the edge of the exterior body, injecting the electrolytic solution into the voids of the electrode group, and vacuum pressurizing the remaining side. rice field. As a result, the lithium ion secondary battery was completed.
  • the positive electrode 21 and the negative electrode 22 were connected to the charging / discharging device, charged at 4.2VCCCV for 30 hours at a current value of 1/20 CA, discharged at 2.5VCC, and charged again under the same conditions.
  • the positive electrode 21 and the third electrode 24 are connected to a charging / discharging device (positive electrode is +, third electrode is-), and a constant current of 120 mAh (negative electrode capacity-75% of positive electrode capacity) at a current value of 1/100 CA. Discharge was performed.
  • Example 1 The same procedure as in Example 1 was carried out except that all the negative electrodes 22 were coated on both sides and the discharge capacity between the positive electrode 21 and the third electrode 24 was 0 mAh. That is, the single-sided coating negative electrode 23 was not provided, and all were negative electrodes 22.
  • Comparative Example 2 The positive electrode and the third electrode were connected to a charging / discharging device (positive electrode is +, third electrode is ⁇ ), and 40 mAh (negative electrode capacity-25% of positive electrode capacity) constant current discharge was performed at a current value of 1/100 CA. Other than this, it was the same as in Comparative Example 1.
  • Comparative Example 3 The positive electrode and the third electrode were connected to a charging / discharging device (positive electrode is +, third electrode is ⁇ ), and a constant current discharge of 80 mAh (negative electrode capacity-50% of positive electrode capacity) was performed at a current value of 1/100 CA. Other than this, it was the same as in Comparative Example 1.
  • Comparative Example 4 The positive electrode and the third electrode were connected to a charging / discharging device (positive electrode is +, third electrode is ⁇ ), and 120 mAh (negative electrode capacity-75% of positive electrode capacity) constant current discharge was performed at a current value of 1/100 CA. Other than this, it was the same as in Comparative Example 1.
  • Comparative Example 5 The positive electrode and the third electrode were connected to a charging / discharging device (positive electrode is +, third electrode is ⁇ ), and 160 mAh (negative electrode capacity-100% of positive electrode capacity) constant current discharge was performed at a current value of 1/100 CA. Other than this, it was the same as in Comparative Example 1.
  • Comparative Example 6 The positive electrode and the third electrode were connected to a charging / discharging device (positive electrode is +, third electrode is ⁇ ), and 200 mAh (negative electrode capacity-125% of positive electrode capacity) constant current discharge was performed at a current value of 1/100 CA. Other than this, it was the same as in Comparative Example 1.
  • the facing surface of the negative electrode 23 facing the third pole 24 is uncoated, and the negative electrode metal foil 23a faces the third pole 24, so that the negative electrode 23 does not face the positive electrode 21 during charging and discharging. It is considered that the recovery efficiency was improved by suppressing the insertion of lithium into the surface of the negative electrode 23 (the surface side of the negative electrode 23 facing the third electrode 24).
  • the negative electrode active material is not formed on the facing surface of the negative electrode facing the third electrode 24, that is, the third.

Abstract

According to the present invention, the fixation of lithium ions and the excessive replenishment of lithium ions due to repeated charge-discharge cycles can be prevented. Provided is a lithium ion secondary battery which has a cell comprising a positive electrode 21, a negative electrode and a third electrode 24. The negative electrode comprises a double-side-coated negative electrode 22 comprising a negative electrode metal foil 22a of which each surface is coated with a negative electrode mix layer 22b and a single-side-coated negative electrode 23 comprising a negative electrode metal foil 23a of which one surface is coated with a negative electrode mix layer 23b. The third electrode 24 is arranged so as to face a surface of the single-side-coated negative electrode 23 on which the negative electrode metal foil 23a is exposed.

Description

リチウムイオン二次電池Lithium ion secondary battery
　本発明は、リチウムイオン二次電池に関する。 The present invention relates to a lithium ion secondary battery.
　リチウムイオン二次電池は、非水電解質二次電池の一つであり、エネルギー密度が高いため、携帯機器のバッテリーや、近年では電気自動車のバッテリーとしても用いられている。しかし、リチウムイオン二次電池は、使用に伴い、劣化し、電池容量が減少することが知られている。 Lithium-ion secondary batteries are one of the non-aqueous electrolyte secondary batteries, and because of their high energy density, they are also used as batteries for portable devices and, in recent years, as batteries for electric vehicles. However, it is known that a lithium ion secondary battery deteriorates with use and the battery capacity decreases.
　リチウムイオン二次電池では、一般に、正極の活物質としてリチウム金属酸化物が用いられ、負極の活物質として黒鉛などの炭素材が用いられている。リチウムイオン電池の正極及び負極は、微小な活物質粒子群にバインダや導電剤等を加えてスラリー化した後、金属箔に塗工することによって作製される。 In a lithium ion secondary battery, a lithium metal oxide is generally used as an active material for a positive electrode, and a carbon material such as graphite is used as an active material for a negative electrode. The positive electrode and the negative electrode of a lithium ion battery are manufactured by adding a binder, a conductive agent, or the like to a group of minute active material particles to form a slurry, and then applying the mixture to a metal foil.
　充電時には正極の活物質から放出されたリチウムイオンが負極の活物質に吸蔵され、放電時には負極の活物質に吸蔵されたリチウムイオンが放出され正極の活物質に吸蔵される。このように、リチウムイオンが電極間を移動することで、電極間に電流が流れる。
　このようなリチウムイオン二次電池では、正極活物質の電気的な孤立、負極活物質の電気的な孤立、リチウムイオンの固定化等によって、電池容量が減少する。
　これらの要因のうち、リチウムイオンの固定化については、初回の充放電における固定化と、充放電サイクルの繰り返しによる固定化とがある。 At the time of charging, the lithium ions released from the active material of the positive electrode are occluded in the active material of the negative electrode, and at the time of discharging, the lithium ions stored in the active material of the negative electrode are occluded and stored in the active material of the positive electrode. As the lithium ions move between the electrodes in this way, a current flows between the electrodes.
In such a lithium ion secondary battery, the battery capacity is reduced due to the electrical isolation of the positive electrode active material, the electrical isolation of the negative electrode active material, the immobilization of lithium ions, and the like.
Among these factors, the immobilization of lithium ions includes immobilization in the initial charge / discharge and immobilization by repeating the charge / discharge cycle.
　特許文献１には、SiO負極の不可逆容量に起因する電池容量の低下を補うことを目的として、第三極と負極を接合し、負極の不可逆容量に相当するリチウムをプレドープする技術が示されている。 Patent Document 1 discloses a technique of joining a third electrode and a negative electrode and pre-doping lithium corresponding to the irreversible capacity of the negative electrode for the purpose of compensating for a decrease in battery capacity due to the irreversible capacity of the SiO negative electrode. There is.
特開２０１７－１２０７４６号公報Japanese Unexamined Patent Publication No. 2017-12746
　特許文献１に記載のリチウムイオン二次電池においては、最初の充電により生じる負極の不可逆容量についての補充がされている。しかしながら、特許文献１の技術では、充放電サイクルの繰り返しによるリチウムイオンの固定化についてはリチウムを補充することができない。 In the lithium ion secondary battery described in Patent Document 1, the irreversible capacity of the negative electrode generated by the initial charging is replenished. However, in the technique of Patent Document 1, lithium cannot be replenished for the immobilization of lithium ions by repeating the charge / discharge cycle.
　本発明の目的は、充放電サイクルの繰り返しによるリチウムイオンの固定化及びリチウムイオンの過剰な補充を抑制することができるリチウムイオン二次電池を提供することにある。 An object of the present invention is to provide a lithium ion secondary battery capable of suppressing immobilization of lithium ions and excessive replenishment of lithium ions due to repeated charge / discharge cycles.
　本発明のリチウムイオン二次電池は、正極と、負極と、第三極とを含むセルを有するリチウムイオン二次電池であって、前記負極は、負極金属箔の両面に負極合剤層が塗工された両面塗工負極と、負極金属箔の片面に負極合剤層が塗工された片面塗工負極とを有し、　前記第三極は、前記片面塗工負極の負極金属箔が露出する面に対向して配置されていることを特徴とする。 The lithium ion secondary battery of the present invention is a lithium ion secondary battery having a cell including a positive electrode, a negative electrode, and a third electrode, and the negative electrode is coated with a negative electrode mixture layer on both sides of a negative electrode metal foil. It has a double-sided coated negative electrode and a single-sided coated negative electrode with a negative electrode mixture layer coated on one side of the negative electrode metal foil. The third pole exposes the negative electrode metal foil of the single-sided coated negative electrode. It is characterized in that it is arranged so as to face the surface of the surface.
　本発明によれば、充放電サイクルの繰り返しによるリチウムイオンの固定化及びリチウムイオンの過剰な補充を抑制することができ、リチウムイオンの補充に対する回復効率が改善し、第三電極の薄膜化と負極片面塗工によるエネルギー密度の向上が図れる。 According to the present invention, it is possible to suppress the immobilization of lithium ions and the excessive replenishment of lithium ions due to repeated charge / discharge cycles, improve the recovery efficiency for lithium ion replenishment, thinn the third electrode, and reduce the thickness of the negative electrode. The energy density can be improved by single-sided coating.
本実施形態のリチウムイオン二次電池の構成を模式的に示す図。The figure which shows typically the structure of the lithium ion secondary battery of this embodiment. 図１に示すセルの模式断面図。FIG. 3 is a schematic cross-sectional view of the cell shown in FIG. 捲回体の一部を分解して示す斜視図。The perspective view which shows the part of the winding body disassembled.
　以下、本発明の実施形態について、図面を参照して説明する。
　図１は、本実施形態のリチウムイオン二次電池の構成を模式的に示す図である。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram schematically showing a configuration of a lithium ion secondary battery of the present embodiment.
　本実施形態のリチウムイオン二次電池は、充放電サイクルの繰り返しによるリチウムイオンの固定化によって電池容量が減少した場合に、リチウムイオンを追加して電池容量を回復させる回復機能付きのリチウムイオン二次電池である。 The lithium ion secondary battery of the present embodiment is a lithium ion secondary battery with a recovery function that recovers the battery capacity by adding lithium ions when the battery capacity decreases due to the immobilization of lithium ions by repeating the charge / discharge cycle. It is a battery.
　図１に示すリチウムイオン二次電池１００は、積層型のリチウムイオン二次電池である。リチウムイオン二次電池１００は、セル１を有している。セル１は、ラミネートフィルム製の容器１０の内部に設置され、周囲が電解液で満たされた構成を有している。つまり、セル１は、電解液で満たされている容器１０の内部に収容されている。 The lithium ion secondary battery 100 shown in FIG. 1 is a laminated lithium ion secondary battery. The lithium ion secondary battery 100 has a cell 1. The cell 1 is installed inside a container 10 made of a laminated film, and has a structure in which the periphery is filled with an electrolytic solution. That is, the cell 1 is housed inside the container 10 filled with the electrolytic solution.
　容器１０の上部は、開放され、金属製の正極タブ５、負極タブ７及び第三極タブ６が突出している。セル１には、図２に示すように正極２１、負極２２、２３及びセパレータ２５が積層され、第三極２４が設けられている。負極２２の放電容量は、正極２１の放電容量より大きいことが望ましい。本実施形態では、負極２２の負極合剤層２２ｂの方が正極２１の正極合剤層２１ｂよりも広くなっており、負極２２と正極２１を重ねたときに、正極活物質塗工面２１ｂの端部よりも負極活物質塗工面２２ｂの端部の方が突出する大きさを有している。 The upper part of the container 10 is opened, and the metal positive electrode tab 5, negative electrode tab 7, and third electrode tab 6 project. As shown in FIG. 2, the cell 1 is provided with a positive electrode 21, negative electrodes 22, 23 and a separator 25 laminated and a third pole 24 is provided. It is desirable that the discharge capacity of the negative electrode 22 is larger than the discharge capacity of the positive electrode 21. In the present embodiment, the negative electrode mixture layer 22b of the negative electrode 22 is wider than the positive electrode mixture layer 21b of the positive electrode 21, and when the negative electrode 22 and the positive electrode 21 are overlapped, the edge of the positive electrode active material coated surface 21b is formed. The end portion of the negative electrode active material coated surface 22b has a size that protrudes more than the portion.
　図２は、図１に示すセルの模式断面図であり、セル内部の積層状態がわかるように示したものである。 FIG. 2 is a schematic cross-sectional view of the cell shown in FIG. 1, and is shown so that the laminated state inside the cell can be understood.
　セル１は、シート状の電極を積層した積層体により構成されている。つまり、セル１は、図２に示すように、それぞれシート形状を有する正極２１と両面塗工負極２２と片面塗工負極２３がセパレータ２５を介して交互に配置されて積層された構造となっている。セル１は、積層方向両側から挟み込むように一対の第三極２４が配置されている。そして、更にその積層方向両側には一対のセパレータ２５が配置されており、セル１の図中の左右の端部は、セパレータ２５で覆われている。 Cell 1 is composed of a laminated body in which sheet-shaped electrodes are laminated. That is, as shown in FIG. 2, the cell 1 has a structure in which a positive electrode 21 having a sheet shape, a double-sided coated negative electrode 22, and a single-sided coated negative electrode 23 are alternately arranged and laminated via a separator 25. There is. In the cell 1, a pair of third poles 24 are arranged so as to be sandwiched from both sides in the stacking direction. Further, a pair of separators 25 are arranged on both sides in the stacking direction, and the left and right ends of the cell 1 in the drawing are covered with the separators 25.
　セル１は、正極金属箔２１ａの両面に正極合剤層２１ｂが塗工された正極２１と、負極金属箔２２ａの両面に負極合剤層２２ｂが塗工された両面塗工負極２２と、負極金属箔２３ａの片面に負極合剤層２３ｂが塗工された片面塗工負極２３と、金属箔２４ａの両面に合剤層２４ｂが塗工された第三極２４とが、それぞれの間にセパレータ２５を介して積層された構成を有している。第三極２４は、本実施形態では、正極２１と同じ構成、つまり、正極金属箔の両面に正極合剤層が塗工された構成を有している。 The cell 1 has a positive electrode 21 in which the positive electrode mixture layer 21b is coated on both sides of the positive electrode metal foil 21a, a double-sided coating negative electrode 22 in which the negative electrode mixture layer 22b is coated on both sides of the negative electrode metal foil 22a, and a negative electrode. A single-sided coating negative electrode 23 in which the negative electrode mixture layer 23b is coated on one side of the metal foil 23a, and a third pole 24 in which the mixture layer 24b is coated on both sides of the metal foil 24a are separated between each other. It has a structure in which 25 is laminated. In the present embodiment, the third pole 24 has the same structure as the positive electrode 21, that is, the positive electrode mixture layer is coated on both sides of the positive electrode metal foil.
　セル１は、正極２１と、両面塗工負極２２とが交互に積層され、その積層体の最も外側に配置される正極２１の積層方向外側に片面塗工負極２３が配置され、片面塗工負極２３の積層方向外側に第三極２４が配置されている。片面塗工負極２３は、負極合剤層２３ｂが積層方向内側に配置され、負極金属箔２３ａが積層方向外側に配置されており、負極合剤層２３ｂが正極２１に対向し、負極金属箔２３ａが第三極２４に対向して配置されている。そして、第三極２４は、片面塗工負極２３の負極金属箔２３ａが露出する面に対向して配置されている。 In the cell 1, the positive electrode 21 and the double-sided coated negative electrode 22 are alternately laminated, and the single-sided coated negative electrode 23 is arranged outside the stacking direction of the positive electrode 21 arranged on the outermost side of the laminated body, and the single-sided coated negative electrode 23 is arranged. The third pole 24 is arranged outside the stacking direction of the 23. In the single-sided coated negative electrode 23, the negative electrode mixture layer 23b is arranged inside in the lamination direction, the negative electrode metal foil 23a is arranged outside in the lamination direction, the negative electrode mixture layer 23b faces the positive electrode 21, and the negative electrode metal foil 23a Is arranged to face the third pole 24. The third pole 24 is arranged so as to face the surface of the single-sided coated negative electrode 23 where the negative electrode metal foil 23a is exposed.
　図３は、捲回体の一部を分解して示す斜視図である。
　セル１は、帯状の電極を捲回した捲回体とし、第三極２４を捲回体の捲回軸付近若しくは最外周部に設置した構成としてもよい。例えば、帯状の正極２１と両面塗工負極２２を、間にセパレータ２５を挟んで重ねた状態で捲回し、両面塗工負極２２に連続して片面塗工負極２３を捲回し、その外側にセパレータを介して第三極２４を少なくとも１周以上捲回する構成としてもよい。片面塗工負極２３は、負極金属箔２３ａが第三極２４に対向して配置される構成を有している。 FIG. 3 is a perspective view showing a part of the wound body in an exploded manner.
The cell 1 may be a wound body in which a band-shaped electrode is wound, and the third pole 24 may be installed near the winding axis of the wound body or at the outermost peripheral portion. For example, the strip-shaped positive electrode 21 and the double-sided coated negative electrode 22 are wound in a state of being overlapped with a separator 25 sandwiched between them, and the single-sided coated negative electrode 23 is wound continuously on the double-sided coated negative electrode 22 and the separator is wound on the outside thereof. The third pole 24 may be wound at least one turn or more via the above. The single-sided coating negative electrode 23 has a configuration in which the negative electrode metal foil 23a is arranged so as to face the third pole 24.
　また、捲回体によって構成する他の例として、例えば第三極２４だけを複数回捲回して捲回体の芯を形成し、その芯の外側に、セパレータ２５を介して片面塗工負極２３を、片面塗工負極２３の負極金属箔２３ａが芯に対向するように捲回する。そして、その外周に両面塗工負極２２と正極２１とを間にセパレータ２５を介して捲回する構成としてもよい。この場合、両面塗工負極２２が片面塗工負極２３に連続して形成された構成とすることもできる。 Further, as another example configured by the wound body, for example, only the third pole 24 is wound a plurality of times to form a core of the wound body, and on the outside of the core, a single-sided coating negative electrode 23 is provided via a separator 25. Is wound so that the negative electrode metal foil 23a of the single-sided coating negative electrode 23 faces the core. Then, the double-sided coating negative electrode 22 and the positive electrode 21 may be wound around the outer periphery via a separator 25. In this case, the double-sided coating negative electrode 22 may be formed continuously on the single-sided coating negative electrode 23.
　正極２１、両面塗工負極２２、片面塗工負極２３及び第三極２４はそれぞれ、所定の金属の集電箔（金属箔）に、所定の電極活物質、導電剤、結着剤等を混合したものを塗工することにより作製されている。片面塗工負極２３は、図２に示すように、未塗工部分である負極金属箔２３ａが第三極２４と対向している。第三極２４の活物質は、反応種を内部に含む材料が望ましい。例えば、ＬｉＣｏＯ２、ＬｉＮｉｘＭｎｙＣｏｚＯ２等の正極活物質、Ｌｉ金属を第三極２４の活物質として用いることができる。
　なお、第三極２４の配置については、本図に限定されるものではなく、正極２１又は負極２２、２３との充放電が可能であればよい。 The positive electrode 21, the double-sided coated negative electrode 22, the single-sided coated negative electrode 23, and the third pole 24 are each a predetermined metal collecting foil (metal foil) mixed with a predetermined electrode active material, a conductive agent, a binder, and the like. It is made by painting what has been done. In the single-sided coated negative electrode 23, as shown in FIG. 2, the negative electrode metal foil 23a, which is an uncoated portion, faces the third pole 24. The active material of the third pole 24 is preferably a material containing a reactive species inside. For example, it is possible to use LiCoO 2, LiNi x Mn y Co z O 2 positive active material, such as, a Li metal as the active material of the third pole 24.
The arrangement of the third pole 24 is not limited to this figure, and may be charged or discharged from the positive electrode 21 or the negative electrodes 22 and 23.
　図１に示す状態で、第三極を用いて負極と正極との電位差を変化させる。正極と負極との電位差を変化させる方法としては、第三極を用いて負極のみ所定量充電して負極にリチウムイオンを追加する方法、又は、正極及び負極を充電した後に第三極で正極を放電して正極にリチウムイオンを追加する方法がある。 In the state shown in FIG. 1, the potential difference between the negative electrode and the positive electrode is changed using the third electrode. As a method of changing the potential difference between the positive electrode and the negative electrode, a method of charging only the negative electrode by a predetermined amount using the third electrode and adding lithium ions to the negative electrode, or a method of charging the positive electrode and the negative electrode and then charging the positive electrode with the third electrode. There is a method of discharging and adding lithium ions to the positive electrode.
　上述の例においては、リチウムイオン二次電池がセパレータ２５を有するリチウムイオン電池について説明したが、本発明は、これに限定されるものではなく、セパレータ２５を有しない全固体電池、半固体電池等にも適用可能である。 In the above example, the lithium ion battery in which the lithium ion secondary battery has the separator 25 has been described, but the present invention is not limited to this, and the present invention is not limited to this, and the all-solid-state battery, the semi-solid-state battery, etc., which do not have the separator 25, etc. It is also applicable to.
　以下、実施例を用いて更に具体的に説明する。なお、本発明は、これらの実施例に限定されるものではない。 Hereinafter, a more specific description will be given using examples. The present invention is not limited to these examples.
（実施例１）
　正極合剤層２１ｂを作製するために、正極活物質としてＬｉＮｉ０．５Ｍｎ０．２Ｃｏ０．３、正極導電剤として炭素材料、正極バインダとしてポリフッ化ビニリデン（ＰＶＤＦ）を用いた。正極活物質、正極導電剤及び正極バインダの質量比率は、９３：４：３とし、これらを混合した正極合剤層スラリーを、分散溶媒であるＮ－メチル－２－ピロリドンにより粘度を調整しながら、１５μｍのアルミニウム箔（正極集電体）に塗工し、正極合剤層を作製した。正極合剤層の塗工量は、３００ｇ／ｍ２とした。塗工後の正極を１２０℃で乾燥した後、ロールプレスで密度を調整し、正極合剤層２１ｂの密度を３．０ｇ／ｃｍ３とした。 (Example 1)
In order to prepare the positive electrode mixture layer 21b, LiNi 0.5 Mn 0.2 Co 0.3 was used as the positive electrode active material, a carbon material was used as the positive electrode conductive agent, and polyvinylidene fluoride (PVDF) was used as the positive electrode binder. The mass ratio of the positive electrode active material, the positive electrode conductive agent, and the positive electrode binder is 93: 4: 3, and the positive electrode mixture layer slurry in which these are mixed is adjusted in viscosity with N-methyl-2-pyrrolidone as a dispersion solvent. , A 15 μm aluminum foil (positive electrode current collector) was coated to prepare a positive electrode mixture layer. The coating amount of the positive electrode mixture layer was set to 300 g / m 2 . After the positive electrode after coating was dried at 120 ° C., the density was adjusted by a roll press to adjust the density of the positive electrode mixture layer 21b to 3.0 g / cm 3 .
　負極合剤層２２ｂを作製するために、負極活物質として黒鉛、負極導電剤として炭素材料、負極バインダとしてスチレン－ブタジエンゴム（ＳＢＲ）及びカルボキシメチルセルロース（ＣＭＣ）を用いた。負極活物質、ＳＢＲ及びＣＭＣの質量比率は、９８：１：１とし、これらを混合した負極合剤層スラリーを、水で粘度を調整しながら、１０μｍの銅箔（負極集電体）に塗工し、負極合剤層２２ｂを作製した。負極合剤層２２ｂの両面塗工量は、１９０ｇ／ｍ２とし、片面塗工と両面塗工の２種類作製した。塗工後の負極を１００℃で乾燥した後、ロールプレスで密度を調整し、負極合剤層２２ｂの密度を１．５ｇ／ｃｍ３とした。 In order to prepare the negative electrode mixture layer 22b, graphite was used as the negative electrode active material, a carbon material was used as the negative electrode conductive agent, and styrene-butadiene rubber (SBR) and carboxymethyl cellulose (CMC) were used as the negative electrode binder. The mass ratio of the negative electrode active material, SBR, and CMC is 98: 1: 1, and the negative electrode mixture layer slurry in which these are mixed is applied to a 10 μm copper foil (negative electrode current collector) while adjusting the viscosity with water. The work was carried out to prepare a negative electrode mixture layer 22b. The amount of double-sided coating of the negative electrode mixture layer 22b was 190 g / m 2, and two types of coating, single-sided coating and double-sided coating, were produced. After the negative electrode after coating was dried at 100 ° C., the density was adjusted by a roll press to adjust the density of the negative electrode mixture layer 22b to 1.5 g / cm 3 .
　第三極には、正極と同じ構成のものを用いた。 For the third electrode, the one having the same configuration as the positive electrode was used.
　正極２１、負極２２、２３及び第三極２４を所定のサイズに裁断した。裁断の際、正極２１、負極２２、２３及び第三極２４において、それぞれ電極集電体の一部に電極合剤層が塗工されてない電極タブ５、７、６を残した。裁断した正極２１と負極２２とをこれらの間にセパレータ２５を挟みながら交互に積層し、最も外側の負極は、片面塗工負極２３とし、片面塗工負極２３の外側に第三極２４を配置して第三極２４と対向させた。片面塗工負極２３は、未塗工面である負極金属箔２３ａを第三極２４と対向させて配置し、セル１とした。セル１の複数の正極タブ５、複数の負極タブ７及び複数の第三極タブ６はそれぞれ束ね、リチウムイオン二次電池の内外を電気的に接続する正極端子、負極端子及び第三極端子にそれぞれ、束ねた電極タブを超音波溶接した。 The positive electrode 21, the negative electrode 22, 23 and the third electrode 24 were cut to a predetermined size. At the time of cutting, the electrode tabs 5, 7, and 6 in which the electrode mixture layer was not coated on a part of the electrode current collector were left in the positive electrode 21, the negative electrode 22, 23, and the third electrode 24, respectively. The cut positive electrode 21 and the negative electrode 22 are alternately laminated with a separator 25 sandwiched between them. The outermost negative electrode is a single-sided coated negative electrode 23, and the third electrode 24 is arranged outside the single-sided coated negative electrode 23. Then, it was made to face the third pole 24. In the single-sided coated negative electrode 23, the negative electrode metal foil 23a, which is an uncoated surface, was arranged so as to face the third pole 24 to form cell 1. The plurality of positive electrode tabs 5, the plurality of negative electrode tabs 7 and the plurality of third electrode tabs 6 of the cell 1 are bundled and connected to the positive electrode terminal, the negative electrode terminal and the third electrode terminal that electrically connect the inside and outside of the lithium ion secondary battery. The bundled electrode tabs were ultrasonically welded, respectively.
　作製した正極２１の容量は３００ｍＡｈであり、正極対向部の負極２２の容量は４６０ｍＡｈである。作製したセル１を外装体内に入れ、外装体の縁部を１７５℃で１０秒間熱溶着封止し、電気的に絶縁した状態で正極端子及び負極端子をリチウムイオン二次電池の外部に突出するようにした。封止は、注液口を設けるために、外装体の縁部の一辺以外をはじめに熱溶着し、電解液を電極群の空隙に注液し、残りの一辺を真空加圧しながら熱溶着により行った。これにより、リチウムイオン二次電池を完成させた。 The capacity of the produced positive electrode 21 is 300 mAh, and the capacity of the negative electrode 22 opposite the positive electrode is 460 mAh. The prepared cell 1 is placed inside the exterior body, the edge of the exterior body is heat-welded and sealed at 175 ° C. for 10 seconds, and the positive electrode terminal and the negative electrode terminal are projected to the outside of the lithium ion secondary battery in an electrically insulated state. I did. In order to provide a liquid injection port, sealing is performed by heat welding except for one side of the edge of the exterior body, injecting the electrolytic solution into the voids of the electrode group, and vacuum pressurizing the remaining side. rice field. As a result, the lithium ion secondary battery was completed.
　その後、正極２１と負極２２を充放電装置に接続し、１／２０ＣＡの電流値で４．２ＶＣＣＣＶ、３０時間の充電と、２．５ＶＣＣ放電を行い、再度同条件で充電した。 After that, the positive electrode 21 and the negative electrode 22 were connected to the charging / discharging device, charged at 4.2VCCCV for 30 hours at a current value of 1/20 CA, discharged at 2.5VCC, and charged again under the same conditions.
　充電後、正極２１と第三極２４とを充放電装置（正極を＋、第三極を－）に接続し、１／１００ＣＡの電流値で１２０ｍＡｈ（負極容量-正極容量の75％）定電流放電を行った。 After charging, the positive electrode 21 and the third electrode 24 are connected to a charging / discharging device (positive electrode is +, third electrode is-), and a constant current of 120 mAh (negative electrode capacity-75% of positive electrode capacity) at a current value of 1/100 CA. Discharge was performed.
（比較例１）
　全ての負極２２を両面塗工とし、正極２１と第三極２４との間の放電容量が０ｍＡｈとしたこと以外は、実施例１と同様にした。つまり、片面塗工負極２３は設けず、全て負極２２とした。 (Comparative Example 1)
The same procedure as in Example 1 was carried out except that all the negative electrodes 22 were coated on both sides and the discharge capacity between the positive electrode 21 and the third electrode 24 was 0 mAh. That is, the single-sided coating negative electrode 23 was not provided, and all were negative electrodes 22.
（比較例２）
　正極と第三極とを充放電装置（正極を＋、第三極を－）に接続し、１／１００ＣＡの電流値で４０ｍＡｈ（負極容量-正極容量の25％）定電流放電を行った。これ以外は、比較例１と同様にした。 (Comparative Example 2)
The positive electrode and the third electrode were connected to a charging / discharging device (positive electrode is +, third electrode is −), and 40 mAh (negative electrode capacity-25% of positive electrode capacity) constant current discharge was performed at a current value of 1/100 CA. Other than this, it was the same as in Comparative Example 1.
（比較例３）
　正極と第三極とを充放電装置（正極を＋、第三極を－）に接続し、１／１００ＣＡの電流値で８０ｍＡｈ（負極容量-正極容量の50％）定電流放電を行った。これ以外は、比較例１と同様にした。 (Comparative Example 3)
The positive electrode and the third electrode were connected to a charging / discharging device (positive electrode is +, third electrode is −), and a constant current discharge of 80 mAh (negative electrode capacity-50% of positive electrode capacity) was performed at a current value of 1/100 CA. Other than this, it was the same as in Comparative Example 1.
（比較例４）
　正極と第三極とを充放電装置（正極を＋、第三極を－）に接続し、１／１００ＣＡの電流値で１２０ｍＡｈ（負極容量-正極容量の75％）定電流放電を行った。これ以外は、比較例１と同様にした。 (Comparative Example 4)
The positive electrode and the third electrode were connected to a charging / discharging device (positive electrode is +, third electrode is −), and 120 mAh (negative electrode capacity-75% of positive electrode capacity) constant current discharge was performed at a current value of 1/100 CA. Other than this, it was the same as in Comparative Example 1.
（比較例５）
　正極と第三極とを充放電装置（正極を＋、第三極を－）に接続し、１／１００ＣＡの電流値で１６０ｍＡｈ（負極容量-正極容量の100％）定電流放電を行った。これ以外は、比較例１と同様にした。 (Comparative Example 5)
The positive electrode and the third electrode were connected to a charging / discharging device (positive electrode is +, third electrode is −), and 160 mAh (negative electrode capacity-100% of positive electrode capacity) constant current discharge was performed at a current value of 1/100 CA. Other than this, it was the same as in Comparative Example 1.
（比較例６）
　正極と第三極とを充放電装置（正極を＋、第三極を－）に接続し、１／１００ＣＡの電流値で２００ｍＡｈ（負極容量-正極容量の125％）定電流放電を行った。これ以外は、比較例１と同様にした。 (Comparative Example 6)
The positive electrode and the third electrode were connected to a charging / discharging device (positive electrode is +, third electrode is −), and 200 mAh (negative electrode capacity-125% of positive electrode capacity) constant current discharge was performed at a current value of 1/100 CA. Other than this, it was the same as in Comparative Example 1.
　＜結果及び考察＞
　表１は、実施例１と比較例１～６についてまとめて示したものである。
　本表に示すように、実施例１は、比較例１～６と比較して、初期容量が向上している。また、正極２１と第三極２４を用いて同じ容量放電した実施例１と比較例４では、回復効率（＝（回復後容量-回復前容量）/回復量）が改善している。実施例１では第三極２４と対向する負極２３の対向面を未塗工とし、第三極２４に負極金属箔２３ａを対向させたことで、充放電時に正極２１と対向していない負極２３の面（第三極２４に対向する負極２３の面側）にリチウムが挿入されることを抑制し、回復効率が改善したと考えられる。 <Results and discussion>
Table 1 summarizes Example 1 and Comparative Examples 1 to 6.
As shown in this table, the initial capacity of Example 1 is improved as compared with Comparative Examples 1 to 6. Further, in Example 1 and Comparative Example 4 in which the positive electrode 21 and the third electrode 24 were discharged in the same capacity, the recovery efficiency (= (capacity after recovery-capacity before recovery) / recovery amount) was improved. In the first embodiment, the facing surface of the negative electrode 23 facing the third pole 24 is uncoated, and the negative electrode metal foil 23a faces the third pole 24, so that the negative electrode 23 does not face the positive electrode 21 during charging and discharging. It is considered that the recovery efficiency was improved by suppressing the insertion of lithium into the surface of the negative electrode 23 (the surface side of the negative electrode 23 facing the third electrode 24).
　すなわち、充放電サイクルの繰り返しによるリチウムイオンの固定化及びリチウムイオンの過剰な補充を抑制することができ、第三極２４と対向する負極の対向面に負極活物質を形成しない、つまり、第三極２４に片面塗工負極２３の負極金属箔２３ａを対向させることでリチウムイオンの補充に対する回復効率が改善し、第三極２４の薄膜化と負極片面塗工によるエネルギー密度の向上が図れる。なお、初期回復でデータを示したが、当然のことながらサイクル後でも同様の結果が得られる。 That is, it is possible to suppress the immobilization of lithium ions and the excessive replenishment of lithium ions due to the repetition of the charge / discharge cycle, and the negative electrode active material is not formed on the facing surface of the negative electrode facing the third electrode 24, that is, the third. By facing the negative electrode metal foil 23a of the single-sided coating negative electrode 23 to the pole 24, the recovery efficiency against lithium ion replenishment is improved, and the thinning of the third electrode 24 and the improvement of the energy density by the negative electrode single-sided coating can be achieved. Although the data was shown in the initial recovery, the same result can be obtained after the cycle as a matter of course.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　１・・・セル、２５・・・セパレータ、５・・・正極タブ、６・・・第三極タブ、７・・・負極タブ、２１・・・正極、２２・・・両面塗工負極、２３・・・片面塗工負極、２４・・・第三極、１００・・・リチウムイオン二次電池 1 ... cell, 25 ... separator, 5 ... positive electrode tab, 6 ... third pole tab, 7 ... negative electrode tab, 21 ... positive electrode, 22 ... double-sided coating negative electrode, 23 ... Single-sided coating Negative electrode, 24 ... Third electrode, 100 ... Lithium ion secondary battery

Claims (5)

  1. 　正極と、負極と、第三極とを含むセルを有するリチウムイオン二次電池であって、
    　前記負極は、負極金属箔の両面に負極合剤層が塗工された両面塗工負極と、負極金属箔の片面に負極合剤層が塗工された片面塗工負極とを有し、
    　前記第三極は、前記片面塗工負極の負極金属箔が露出する面に対向して配置されていることを特徴とするリチウムイオン二次電池。     A lithium ion secondary battery having a cell containing a positive electrode, a negative electrode, and a third electrode.
    The negative electrode has a double-sided coated negative electrode in which a negative electrode mixture layer is coated on both sides of the negative electrode metal foil, and a single-sided coated negative electrode in which a negative electrode mixture layer is coated on one side of the negative electrode metal foil.
    The lithium ion secondary battery is characterized in that the third pole is arranged so as to face the surface on which the negative electrode metal foil of the single-sided coated negative electrode is exposed.
  2. 　前記負極の放電容量は、前記正極の放電容量より大きいことを特徴とする請求項１に記載のリチウムイオン二次電池。 The lithium ion secondary battery according to claim 1, wherein the discharge capacity of the negative electrode is larger than the discharge capacity of the positive electrode.
  3. 　前記正極は、正極金属箔と、該正極金属箔の両面に塗工された正極合剤層とを有し、
    　前記第三極は、前記正極と同一の金属箔および該金属箔の両面に塗工された合剤層を有することを特徴とする請求項１に記載のリチウムイオン二次電池。     The positive electrode has a positive electrode metal foil and a positive electrode mixture layer coated on both sides of the positive electrode metal foil.
    The lithium ion secondary battery according to claim 1, wherein the third pole has the same metal foil as the positive electrode and a mixture layer coated on both sides of the metal foil.
  4. 　前記セルは、前記正極と前記両面塗工負極とが交互に積層され、前記正極の積層方向外側に前記片面塗工負極が配置され、該片面塗工負極の積層方向外側に前記第三極が配置されていることを特徴とする請求項１に記載のリチウムイオン二次電池。 In the cell, the positive electrode and the double-sided coated negative electrode are alternately laminated, the single-sided coated negative electrode is arranged outside the stacking direction of the positive electrode, and the third pole is located outside the laminated direction of the single-sided coated negative electrode. The lithium ion secondary battery according to claim 1, wherein the lithium ion secondary battery is arranged.
  5. 　前記セルは、帯状の正極と帯状の両面塗工負極とを間にセパレータを介して重ねた状態で捲回し、前記両面塗工負極に連続して前記片面塗工負極を捲回し、該片面塗工負極の外側に前記第三極を捲回した捲回体を有していることを特徴とする請求項１に記載のリチウムイオン二次電池。 In the cell, a band-shaped positive electrode and a band-shaped double-sided coated negative electrode are wound in a state of being stacked with a separator in between, and the single-sided coated negative electrode is wound continuously on the double-sided coated negative electrode, and the single-sided coating is performed. The lithium ion secondary battery according to claim 1, wherein the lithium ion secondary battery has a wound body in which the third electrode is wound on the outside of the negative electrode.
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JP2011054324A (en) * 2009-08-31 2011-03-17 Nissan Motor Co Ltd Lithium ion secondary battery and method for manufacturing the same
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WO2016051639A1 (en) * 2014-09-29 2016-04-07 パナソニックＩｐマネジメント株式会社 Laminated battery
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JP2010205769A (en) * 2009-02-27 2010-09-16 Fuji Heavy Ind Ltd Wound-type storage device
JP2011054324A (en) * 2009-08-31 2011-03-17 Nissan Motor Co Ltd Lithium ion secondary battery and method for manufacturing the same
JP2014519166A (en) * 2011-05-31 2014-08-07 コミッサリア ア レネルジー アトミーク エ オ ゼネルジ ザルタナテイヴ Semi-automatic method for manufacturing electrochemical lithium-ion batteries
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