WO2009141850A1 - Electrical storage device - Google Patents

Electrical storage device Download PDF

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Publication number
WO2009141850A1
WO2009141850A1 PCT/JP2008/001275 JP2008001275W WO2009141850A1 WO 2009141850 A1 WO2009141850 A1 WO 2009141850A1 JP 2008001275 W JP2008001275 W JP 2008001275W WO 2009141850 A1 WO2009141850 A1 WO 2009141850A1
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WO
WIPO (PCT)
Prior art keywords
negative electrode
storage device
current collector
electricity storage
thickness
Prior art date
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PCT/JP2008/001275
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French (fr)
Japanese (ja)
Inventor
北條伸彦
大塚友
渡邊庄一郎
本田和義
Original Assignee
パナソニック株式会社
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Priority to PCT/JP2008/001275 priority Critical patent/WO2009141850A1/en
Publication of WO2009141850A1 publication Critical patent/WO2009141850A1/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
    • H01G11/02—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 using combined reduction-oxidation reactions, e.g. redox arrangement or solion
    • 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
    • H01G11/04—Hybrid capacitors
    • H01G11/06—Hybrid capacitors with one of the electrodes allowing ions to be reversibly doped thereinto, e.g. lithium ion capacitors [LIC]
    • 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
    • H01G11/26—Electrodes characterised by their structure, e.g. multi-layered, porosity or surface features
    • 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
    • H01G11/50—Electrodes characterised by their material specially adapted for lithium-ion capacitors, e.g. for lithium-doping or for intercalation
    • 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
    • H01G11/66—Current collectors
    • H01G11/70—Current collectors characterised by their structure
    • 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
    • H01G11/74—Terminals, e.g. extensions of current collectors
    • 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

Definitions

  • the present invention relates to an electricity storage device having a high output and a high capacity and having excellent repeated charge / discharge life characteristics.
  • chargeable / dischargeable power storage devices are used for power sources such as hybrid vehicles driven by using two types of energy, gasoline and electricity, various electronic devices, especially mobile communication devices, portable electronic devices, and uninterruptible power supplies. ing.
  • various electronic devices especially mobile communication devices, portable electronic devices, and uninterruptible power supplies.
  • electric double layer capacitors which are one type of power storage device, have been actively conducted. Electric double layer capacitors have the characteristics of high output and excellent repeated charge / discharge life characteristics, and are expected to be applied mainly to high output applications, but have a lower capacity or energy density than secondary batteries. .
  • the positive electrode active material of the electric double layer capacitor and the negative electrode active material of the lithium ion battery optimize the positive electrode active material and the negative electrode active material itself, and optimize the combination
  • the negative electrode active material for example, crystalline or amorphous carbon materials such as graphite and polyacene have been studied. These carbon materials are materials capable of reversibly occluding and releasing lithium ions by charging and discharging.
  • a positive electrode active material of an electric double layer capacitor such as activated carbon and a negative electrode containing these carbon materials are combined (for example, Patent Document 1 and Patent Document 2). reference).
  • a negative electrode active material having a larger capacity density than the carbon material examples include a negative electrode active material obtained by modifying a carbon material, a negative electrode active material other than a carbon material, and the like.
  • a negative electrode active material obtained by modifying the carbon material “a negative electrode active material obtained by activating an optically anisotropic carbonaceous material excluding graphite, and a part or all of the surface thereof is made of a carbon material and / or a silicon material.
  • a coated negative electrode active material is proposed (see, for example, Patent Document 2).
  • metal oxides such as tin oxide and silicon oxide (for example, see Patent Documents 3 and 4) are proposed.
  • Patent Documents 2 to 4 disclose a combination of a negative electrode active material disclosed in each of the patent documents and a positive electrode active material that is activated carbon.
  • Patent Documents 3 and 4 provide an electricity storage device having excellent overdischarge characteristics by combining a negative electrode active material that is a non-carbon material such as silicon oxide or tin oxide with a positive electrode active material that is activated carbon. There is disclosure to be done. More specifically, in Example 1 of Patent Document 3, silicon monoxide particles (negative electrode active material) pulverized and sized to a particle size of 44 ⁇ m or less, graphite (conductive agent), and polyacrylic acid (binder) ) In a weight ratio of 45:40:15, respectively, to prepare a negative electrode mixture.
  • pellet-shaped negative electrode having a diameter of 4 mm and a thickness of 0.19 mm is produced.
  • the pellet-like negative electrode is fixed to the negative electrode case with a conductive resin adhesive that also functions as a negative electrode current collector.
  • the electricity storage device including the pellet-shaped negative electrode can operate in a voltage range including an overdischarge region from 2 V to a discharge end voltage of 0 V, but the charge / discharge rate is very slow at a 200 hour rate (0.005 C rate). The output characteristics are low.
  • lithium secondary batteries often used in electronic devices such as portable electronic devices generally have a charge / discharge rate of about 10 to 0.5 hour rate (0.1 C rate to 2 C rate). Therefore, it is clear that the electricity storage devices of Patent Documents 3 and 4 cannot be used for alternative uses for lithium secondary batteries.
  • An electric double layer capacitor capable of instantaneously charging and discharging a large current generally has a charge / discharge rate of about 0.002 to 0.02 hour rate (500 C rate to 50 C rate). Therefore, the electrical storage device of patent documents 3 and 4 cannot be used also for the alternative use of an electric double layer capacitor.
  • the power storage devices disclosed in Patent Documents 3 and 4 have a high voltage and a high capacity, but their use is limited because the charge / discharge speed is slow and the output characteristics are low.
  • the positive electrode active material an organic compound capable of oxidation and reduction having a capacity higher than that of currently used activated carbon is being studied.
  • organic compounds that can be oxidized and reduced organic compounds having a ⁇ -electron conjugated cloud (for example, see Patent Documents 5 and 6), organic compounds having a radical (for example, see Patent Document 7), and the like have been proposed.
  • these patent documents do not report a combination of a positive electrode active material that is an organic compound capable of redox and a negative electrode active material that is a non-carbon material.
  • the present invention provides a power storage device that can be charged / discharged at high speed despite having a non-carbon material as a negative electrode active material, and has high output, high capacity, and excellent repeated charge / discharge life characteristics.
  • the purpose is to do.
  • the inventors of the present invention have made extensive studies to solve the above problems.
  • the negative electrode has a specific configuration, thereby charging and discharging It has been found that higher speed and, in turn, higher output can be achieved.
  • the electricity storage device has a high charge / discharge rate, high output and high capacity, and excellent repeated charge / discharge life characteristics. Was found and the present invention was completed.
  • an electricity storage device of the present invention includes a positive electrode current collector, a positive electrode including at least a positive electrode active material capable of reversibly adsorbing and desorbing anions disposed on the positive electrode current collector, the negative electrode current collector, A negative electrode made of a negative electrode active material that is substantially reversibly occluded and desorbed and is disposed on the negative electrode current collector, wherein the negative electrode active material comprises silicon, a silicon-containing alloy, and a silicon compound. And at least one selected from the group consisting of tin, tin-containing alloys and tin compounds, wherein the negative electrode is a thin film having a thickness of 10 ⁇ m or less.
  • the capacity per unit area of the negative electrode is preferably 0.2 to 2.0 mAh / cm 2 .
  • the thickness of the positive electrode is preferably 5 times or more the thickness of the negative electrode.
  • the specific surface area of the negative electrode is preferably 5 or more.
  • the negative electrode current collector preferably has a specific surface area of 5 or more.
  • the surface roughness Ra of the negative electrode current collector is equal to or greater than the thickness of the negative electrode. It is preferable that lithium is occluded in advance in the negative electrode active material. It is preferable that lithium is occluded mechanically in the negative electrode active material. At the time of charge / discharge of the electricity storage device, the SOC of the negative electrode is preferably 20% or more and 95% or less.
  • the negative electrode active material is preferably silicon.
  • the negative electrode active material is preferably silicon nitride or silicon oxynitride.
  • the silicon compound is preferably a silicon oxide represented by the formula SiOx (0 ⁇ x ⁇ 2).
  • the positive electrode active material is preferably activated carbon.
  • the positive electrode active material is preferably an organic compound that can be oxidized and reduced.
  • the organic compound preferably has a radical in the molecule.
  • the organic compound preferably has a ⁇ -conjugated electron cloud in the molecule.
  • the negative electrode current collector has an electrolyte holding part, and the volume of the electrolyte holding part is 30% or more of the occupied volume of the negative electrode current collector.
  • the negative electrode current collector has an electrolyte holding part, and the volume of the electrolyte holding part is 50% or more of the occupied volume of the negative electrode current collector.
  • the negative electrode current collector is preferably a porous film having a plurality of through holes penetrating in the thickness direction.
  • the negative electrode current collector does not have a through-hole penetrating in the thickness direction and has a plurality of protrusions on the surface, and the cross-sectional shape of the protrusion in the thickness direction of the negative electrode current collector is trapezoidal or pseudo-trapezoidal.
  • the height of the protrusion is at least twice the thickness of the negative electrode.
  • a coating layer containing a negative electrode active material is formed on at least a part of the tip of the protrusion.
  • an electricity storage device that can be charged / discharged at high speed and has high output, high capacity, and excellent repeated charge / discharge life characteristics. It is possible to provide an electric storage device that does not cause a decrease in capacity even at high output and can stably maintain high output for a long time.
  • FIG. 1 is a longitudinal sectional view schematically showing a configuration of an electricity storage device 1 according to an embodiment of the present invention.
  • 2 is a longitudinal sectional view schematically showing the configuration of a negative electrode 12 formed on the surface of a negative electrode current collector 13.
  • FIG. 4 is a longitudinal sectional view schematically showing a configuration of another form of negative electrode 12a formed on the surface of the negative electrode current collector 13.
  • FIG. 3 is a longitudinal sectional view schematically showing a configuration of a negative electrode current collector 13.
  • FIG. 2 is a longitudinal sectional view schematically showing a configuration of a negative electrode laminate including a negative electrode 12 and a negative electrode current collector 13.
  • FIG. It is a longitudinal cross-sectional view which shows the structure of the negative electrode collector 30 of another form typically.
  • FIG. 4 is a longitudinal sectional view schematically showing a configuration of a negative electrode current collector 35 in which a protrusion 36 has a triangular cross-sectional shape in the thickness direction. It is a longitudinal cross-sectional view which shows typically the structure of the negative electrode laminated body 40 which has the proceedings
  • a schematic perspective view of a mobile phone using the electricity storage device of the present invention It is a schematic perspective view of the notebook PC using the electrical storage device of this invention. It is a schematic block diagram of the hybrid vehicle using the electrical storage device of this invention.
  • the electricity storage device of the present invention includes a positive electrode, a positive electrode current collector, a negative electrode, and a negative electrode current collector, and has the following characteristics (a) and (b). Other configurations are the same as those of the conventional power storage device.
  • the negative electrode does not contain a binder, particularly an organic binder, and contains a non-carbon material capable of reversibly occluding and releasing lithium ions as a negative electrode active material. And the negative electrode active material layer.
  • the non-carbon material capable of reversibly occluding and releasing lithium ions at least one selected from silicon, silicon-containing alloys, silicon compounds, tin, tin-containing alloys and tin compounds is used.
  • a negative electrode is formed by binding particles of a non-carbon material and a conductive agent with a binder.
  • the contact resistance between the active material particles, the contact resistance between the active material particles and the current collector surface, and the active material particles when the negative electrode contains a conductive agent It has been found that contact resistance between the metal and the conductive agent is generated, increasing the internal resistance of the electricity storage device. For this reason, it is presumed that the charge / discharge rate and, consequently, the output is significantly reduced.
  • the negative electrode does not contain a binder, particularly an organic binder, as in the present invention, lithium can be preliminarily occluded in the negative electrode active material by a mechanical charging method using a thin film formation process such as vapor deposition for the first time.
  • the present invention makes it possible to occlude lithium in the negative electrode active material in this way, thereby significantly improving the workability of the electricity storage device.
  • the negative electrode is substantially made of a non-carbon material.
  • this invention also includes the form in which a negative electrode contains an inorganic compound with a non-carbon material.
  • the inorganic compound is used for the purpose of improving the mechanical strength of the negative electrode.
  • the inorganic compound used in combination with the non-carbon material is an inorganic compound that does not contribute to the battery reaction and does not deteriorate even if Li is occluded in the negative electrode.
  • the negative electrode of the present invention is formed as a structure in which non-carbon materials that are negative electrode active materials are continuously connected.
  • contact resistance the electrical contact resistance
  • a negative electrode composed of a thin film having a thickness of 10 ⁇ m or less is directly formed on the surface of the negative electrode current collector.
  • the negative electrode is not directly formed on the negative electrode current collector, but a separately prepared negative electrode is bonded or bonded to the negative electrode current collector.
  • the negative electrode is produced, for example, by mixing particles of a non-carbon material, a conductive agent, and a binder, and pressing the resulting mixture into a pellet.
  • the negative electrode thickness can be significantly reduced as compared with the prior art by directly forming a negative electrode comprising a thin film having a thickness of 10 ⁇ m or less on the surface of the negative electrode current collector.
  • the negative electrode becomes a path for electrons or ions accompanying charging and discharging. Therefore, if the thickness of the negative electrode is small, the movement distance of electrons or ions is shortened, the resistance is reduced, and the internal resistance of the electricity storage device can be reduced.
  • the negative electrode when the negative electrode is directly formed on the surface of the negative electrode current collector, for example, the negative electrode can be formed by vapor deposition or the like, so that the workability of the electricity storage device is significantly improved.
  • the power storage device of the present invention has the features (a) and (b) above, so that the internal resistance is remarkably smaller than that of the conventional power storage device, and charging / discharging at high speed and high output are possible. become. Furthermore, the electricity storage device of the present invention can provide an electricity storage device having a high capacity, excellent repeated charge / discharge life characteristics, and remarkably improved workability by using a non-carbon material as a negative electrode active material. it can. By using this thin film negative electrode, it is possible to reduce the size of the electricity storage device.
  • the thickness of the negative electrode refers to the thickness of the negative electrode when the power storage device is configured (during discharge). Since the negative electrode active material reversibly absorbs and releases lithium during charging and discharging, the thickness of the negative electrode changes.
  • the negative electrode capacity per unit area a negative electrode having a capacity of 0.2 to 2.0 mAh / cm 2 can be used.
  • the negative electrode capacity per unit area is 0.2 to 1.0 mAh / cm 2 .
  • the negative electrode capacity refers to a capacity capable of reversible charge / discharge as a single negative electrode, and does not include an irreversible capacity described later. Specifically, it is a reversible capacity when charging / discharging at 0.2 CA (5-hour rate) with respect to the negative electrode capacity in a potential range of 0 to 1.5 V with respect to lithium.
  • FIG. 1 is a longitudinal sectional view schematically showing a configuration of a coin-type electricity storage device 1 according to an embodiment of the present invention.
  • FIG. 2 is a longitudinal sectional view schematically showing the configuration of the negative electrode 12 formed on the surface of the negative electrode current collector 13.
  • the electricity storage device 1 includes a positive electrode 10, a positive electrode current collector 11, a negative electrode 12, a negative electrode current collector 13, a separator 14, a sealing plate 15, a gasket 16, a spacer 17, and a case 18.
  • FIG. 1 can also be said to be a cross-sectional view of the electricity storage device 1 in the diameter direction. Note that substantially equal pressure is applied to the stacked portion of the positive electrode current collector 11, the positive electrode 10, the separator 14, the negative electrode 12, and the negative electrode current collector 13 in the electricity storage device 1.
  • the negative electrode 12 is a thin film having a thickness of 10 ⁇ m or less. Thereby, it is possible to charge and discharge at high speed, and an electricity storage device having high output, high capacity, and excellent repeated charge / discharge life characteristics can be obtained.
  • the thickness of the negative electrode 12 is preferably 5 ⁇ m or less, more preferably 2 to 5 ⁇ m.
  • the negative electrode 12 is made of a negative electrode active material capable of reversibly occluding and releasing lithium ions, and does not substantially contain an insulating material such as a binder.
  • the negative electrode active material is at least one non-carbon material selected from silicon, a silicon-containing alloy, a silicon compound, tin, a tin-containing alloy, and a tin compound.
  • the negative electrode active material is preferably silicon.
  • the silicon-containing alloy include an alloy of silicon and at least one element selected from iron, cobalt, antimony, bismuth, lead, nickel, copper, zinc, germanium, indium, tin, and titanium.
  • the silicon compound is not particularly limited as long as it is a compound containing silicon other than a silicon-containing alloy, but silicon oxide, silicon nitride, silicon oxynitride and the like are preferable.
  • the silicon oxide include silicon oxide represented by the formula SiOx (0 ⁇ x ⁇ 2). This silicon oxide may contain elements such as nitrogen and sulfur.
  • the silicon nitride include silicon nitride represented by the formula Si 3 N y (3 ⁇ y ⁇ 4). Among these, Si 3 N 4 is preferable.
  • As the silicon oxynitride a compound that contains silicon, oxygen, and nitrogen as main components and may contain an element other than the above three elements (such as carbon and hydrogen) as impurities can be used.
  • a / b about 0.2 to 5.0 can be preferably used.
  • the tin-containing alloy include tin and at least one element selected from iron, cobalt, antimony, bismuth, lead, nickel, copper, silver, zinc, thallium, cadmium, gallium, germanium, indium, and silicon. An alloy etc. are mentioned. Although it will not restrict
  • the tin oxide include tin oxide represented by the formula SnOx (x is the same as above). This tin oxide may contain elements such as nitrogen and sulfur.
  • non-carbon materials may further contain a non-metallic element.
  • a nonmetallic element For example, alkali metals, such as hydrogen, sodium, potassium, and rubidium, alkaline earth metals, such as magnesium and calcium, carbon, boron, nitrogen, phosphorus etc. are mentioned.
  • silicon compounds are preferable, silicon oxides are more preferable, and silicon oxide represented by the formula SiOx (x is the same as above) is particularly preferable.
  • a non-carbon material can be used individually by 1 type, or can be used in combination of 2 or more type as needed.
  • non-carbon materials are characterized by a very large amount of energy.
  • the energy density per volume of the carbon material conventionally used as the negative electrode active material (hereinafter referred to as “conventional carbon material”) is 500 to 600 mAh / cc, whereas for example silicon 2400 mAh / cc, tin oxide 1400 mAh / cc, 3-5 times energy density. Therefore, unlike the case of using a conventional carbon material, the thickness balance between the positive electrode 10 and the negative electrode 12 can be appropriately adjusted. For example, it is possible to provide a thin film-like negative electrode 12 having a thickness of about several ⁇ m.
  • the negative electrode 12 By forming the negative electrode 12 in a thin film shape using a non-carbon material, it is possible to increase the output of the electricity storage device 1 as well as to reduce the size and increase the capacity.
  • the non-carbon material has a very large energy density of about 50 to 80 times that of the positive electrode active material of an electric double layer capacitor such as activated carbon having a volume energy density of about 30 mAh / cc. . Further, since the non-carbon material has a low negative electrode potential as in the case of the conventional carbon material, the electricity storage device 1 having a high voltage of about 3 V can be obtained.
  • a general film forming method such as a vacuum deposition method, a sputtering method, a gas deposition method, a CVD method, or a plating method can be used.
  • the thickness of the negative electrode can be adjusted by appropriately selecting the film forming conditions.
  • a film forming method may be appropriately selected according to the characteristics of the inorganic compound. For example, if the inorganic compound can be deposited, the negative electrode can be formed by co-evaporation of a non-carbon material and an inorganic compound. In this embodiment, as shown in FIG.
  • the negative electrode 12 is formed on the entire surface of the negative electrode current collector 13.
  • the present invention is not limited to this, and the negative electrode 12 is formed in a pattern on the negative electrode current collector 13 surface. Also good.
  • the negative electrode formed in the pattern include a negative electrode 12a shown in FIG.
  • FIG. 3 is a longitudinal sectional view schematically showing the configuration of another form of negative electrode 12 a formed on the surface of the negative electrode current collector 13.
  • the negative electrode 12 a is formed in a striped pattern on the surface of the negative electrode current collector 13. It is not limited to this, For example, you may form in pattern shapes, such as a grid
  • a method of forming the negative electrode 12 in a pattern on the negative electrode current collector 13 for example, a method of forming the negative electrode 12 using a mask, oblique deposition on the negative electrode current collector 13 having irregularities on the surface And a method of partially removing the negative electrode 12 by etching or the like after the negative electrode 12 is formed on the entire surface of the negative electrode current collector 13.
  • the negative electrode 12 is preferably formed in a thin film shape having a specific surface area of 5 or more, more preferably 10 or more. If the specific surface area is less than 5, the capacity drop at the time of high output of the electricity storage device 1 becomes remarkable, and there is a possibility that stable high output cannot be obtained. In addition, although there is no upper limit of the specific surface area, about 10 can be formed at present.
  • the specific surface area of the negative electrode 12 can be adjusted, for example, by appropriately selecting the film forming conditions when the negative electrode is produced according to a general film forming method such as a vacuum deposition method or a sputtering method.
  • the specific surface area means the ratio of the surface area of the set measurement range to the apparent area of the measurement range (surface area of the measurement range / apparent area of the measurement range).
  • the surface area of the measurement range is measured using a laser microscope (trade name: Ultra-deep shape measurement microscope VK-855, manufactured by Keyence Corporation).
  • the method for measuring the surface area of a substance includes the method of measuring only the outer area of the substance, the method of measuring the outer area of the substance and the unevenness of the substance surface, the area of the crack, the outer area of the substance and the unevenness of the substance surface, the crack There is a method of measuring the area of pores extending inside the substance together with the area. And the specific surface area which has a different meaning according to a measuring method is calculated
  • the surface area measurement method using a laser can easily measure the surface area of the measurement range (the sum of the outer area of the substance and the unevenness of the substance surface and the area of the crack) without destroying the measurement object. Furthermore, the surface area measuring method using a laser has an advantage that the surface area of a substance having a specific surface area value of about 3 to 10 can be measured almost accurately. Therefore, the present invention is suitable for measuring the surface area of the negative electrode 12, the negative electrode current collector 13, and the like.
  • the apparent area of the measurement range is an area when the measurement range is assumed to be a plane. Therefore, the apparent area can be automatically calculated by setting the measurement range. Note that, in the measurement method of the present invention, when the measurement range is viewed from above in the vertical direction, the unevenness and cracks that are not visible as shadows are not included in the measurement. Here, “invisible” means not recognized by the laser microscope.
  • the measurement range is set as follows. First, one projection is selected from the surface of the substance to be measured, and this is set as the first projection. Let W be the width of each side of the peripheral edge of the first protrusion. The value of W actually changes from side to side. Next, in the central portion of the first protrusion, a portion that is similar to the first protrusion and the width of each side of the peripheral edge portion is W / 2 or less is set as a measurement range.
  • the predetermined thickness and specific surface area can also be obtained by adjusting the value (roughness value) of the surface roughness (arithmetic average surface roughness) Ra of the surface of the negative electrode current collector 13 on which the negative electrode 12 is formed. Can be formed.
  • the value of the surface roughness Ra of the negative electrode current collector 13 is preferably equal to or greater than the thickness of the negative electrode 12. In other words, it is preferable that the thickness of the negative electrode 12 containing no lithium immediately after formation is equal to or less than the value of the surface roughness Ra of the negative electrode current collector 13.
  • the surface roughness Ra of the negative electrode current collector 13 is preferably 10 ⁇ m or less, more preferably 5 ⁇ m or less, and further preferably 1 to 2 ⁇ m.
  • the surface roughness Ra of the negative electrode current collector 13 can be appropriately adjusted by, for example, a general surface roughening method.
  • the surface roughness Ra of the negative electrode current collector 13 is a value measured by a method defined in JIS B0601-1994 of the Japanese Industrial Standard.
  • the negative electrode 12 having a predetermined thickness and specific surface area can be relatively easily adjusted by adjusting the specific surface area of the negative electrode current collector 13 on which the negative electrode 12 is formed to preferably 5 or more, more preferably 10 or more. Can be formed. Also at this time, it is preferable to appropriately select film formation conditions such as film formation time so that the thickness of the negative electrode 12 is equal to or less than the value of the surface roughness Ra of the negative electrode current collector 13.
  • the SOC (state of charge) of the negative electrode is preferably 20% or more and 95% or less.
  • the SOC of the negative electrode is an index that represents the state of charge of the single negative electrode, not as a power storage device, and the ratio of the charge amount to the full charge amount with the capacity (reversible capacity) when the negative electrode is fully charged being 100%. Is a value expressed as a percentage. Therefore, the fully discharged SOC is 0%, and the fully charged SOC is 100%.
  • the SOC of the negative electrode is determined by the following method. In the potential range of 0 to 1.5 V with respect to lithium, the SOC of the negative electrode when charged at 0.2 CA (5-hour rate) with respect to the negative electrode capacity is 100% (full charge) The SOC value can be determined based on this charge amount.
  • the negative electrode current collector 13 has a plurality of through holes 20 that penetrate the film-like negative electrode current collector 13 in the thickness direction, and the through holes 20 serve as an electrolyte holding portion. .
  • the negative electrode current collector 13 there are a plurality of open cells 21 extending mainly in the thickness direction of the negative electrode current collector 13.
  • One end of the open cell 21 reaches one surface in the thickness direction of the negative electrode current collector 13, and the other end of the open cell 21 reaches the other surface in the thickness direction of the negative electrode current collector 13.
  • a plurality of bubbles are continuously connected to each other in the continuous bubble 21, and each bubble has an internal space. Therefore, inside the continuous bubble 21, the internal space of each bubble communicates to form one through hole 20.
  • the electrolytic solution can be impregnated and held in the through hole 20. That is, an anion and cation electrolyte (electrolytic solution) can be held inside the negative electrode current collector 13 provided in contact with the negative electrode 12. Even if the negative electrode 12 cannot sufficiently hold the electrolyte therein, a sufficient amount of electrolyte can be secured inside the electricity storage device 1 by holding a sufficient amount of electrolyte inside the negative electrode current collector 13. .
  • the negative electrode 12 is formed on one surface in the thickness direction of the negative electrode current collector 13 having a plurality of through holes 20.
  • the thickness of the negative electrode 12 is preferably set to the thickness of the through hole 20. It is better to make it smaller than the hole diameter.
  • the hole diameter of the through hole 20 is preferably larger than the thickness of the negative electrode 12.
  • the hole diameter of the through hole 20 is preferably at least twice the thickness of the negative electrode 12, more preferably at least 5 times, and even more preferably at 5 to 100 times.
  • the hole diameter of the through-hole 20 can be measured by, for example, gas adsorption measurement or a mercury porosimeter.
  • the hole diameter of the through-hole 20 generally has a distribution, it can be handled as the hole diameter of the through-hole 20 with the volume-based median pore diameter as a representative value.
  • the ratio of the volume of the electrolyte holding portion (the sum of the internal volumes of the through holes 20) to the volume occupied by the negative electrode current collector 13 (hereinafter simply referred to as “volume ratio of the electrolyte holding portion”) is 30% or more. Is preferred.
  • the volume ratio of the electrolyte holding portion is more preferably 50% or more, and further preferably 50 to 95%. When the volume ratio of the electrolyte holding part is less than 30%, the amount of electrolyte salt in the vicinity of the negative electrode 12 becomes insufficient, and the charge / discharge capacity of the electricity storage device 1 may be reduced.
  • the volume ratio of the electrolyte holding part can be measured, for example, by gas adsorption measurement or mercury porosimeter.
  • a measurement using a specific surface area / pore distribution measuring instrument (trade name: ASAP2010, manufactured by Shimadzu Corporation) is given as an example.
  • This measuring device is a device that measures the pore volume by using gas adsorption and desorption, and can measure pores having a pore diameter of about several to 0.1 ⁇ m.
  • Another example is measurement using a mercury porosimeter (trade name: Autopore III 9410, manufactured by Shimadzu Corporation).
  • This measuring device is a device that measures the pore volume by using mercury intrusion into the pores, and can measure pores having a pore diameter of about several nm to 500 ⁇ m.
  • the negative electrode current collector 13 having the through holes 20 for example, a porous body such as a foam or a mesh body can be used.
  • a material which comprises the negative electrode collector 13 what is used for the negative electrode collector of a lithium ion battery can be used, however, considering the workability of porous formation etc., metal materials, such as copper and nickel, are used. preferable.
  • the open cell formed inside the foam is the electrolyte holding part, the total volume of the open cells is the volume of the electrolyte holding part, and the porosity of the foam is occupied by the negative electrode current collector 13. This is the volume ratio of the electrolyte holding part to the volume.
  • FIG. 6 is a longitudinal sectional view schematically showing the configuration of another form of negative electrode current collector 30.
  • FIG. 7 is a longitudinal sectional view schematically showing a configuration of a negative electrode laminate including the thin film negative electrode 33 and the negative electrode current collector 30 shown in FIG.
  • the negative electrode current collector 30 includes a current collecting film 31 and a protrusion 32.
  • the current collecting film 31 is made of a material used for a negative electrode current collector of a lithium ion battery.
  • a plurality of protrusions 32 are formed on both surfaces of the current collecting film 31 in the thickness direction so as to extend from the surface of the current collecting film 31 toward the outside of the current collecting film 31.
  • the current collecting film 31 does not have a through hole penetrating in the thickness direction.
  • the negative electrode 33 is formed at least at the tip of the protrusion 32.
  • the negative electrode current collector 30 and the separator 14 are brought into contact with each other via the negative electrode 33, a space in which the negative electrode current collector 30 and the separator 14 are not in direct contact is formed due to the presence of the protrusion 32.
  • the amount of electrolyte salt necessary for the negative electrode reaction can be secured in the vicinity of the negative electrode 33. That is, this space becomes an electrolyte holding part.
  • the volume of the electrolyte holding portion can be calculated by multiplying the non-occupied area of the protrusion with respect to the current collector area by the protrusion height.
  • the non-occupied area of the protrusions with respect to the current collector area is the ratio of the total area of the area where the protrusions are not formed on the current collector surface in the area of the current collector film.
  • the protrusion height and the unoccupied area of the protrusion relative to the current collector area can be measured by surface observation and cross-sectional observation of the current collector film using a laser microscope or an electron microscope. Specifically, for example, a laser microscope (trade name: VK-855, manufactured by Keyence Corporation) can be used.
  • the protrusion 32 is preferably formed so as to be in contact with the separator 14 not by a point but by a surface through a negative electrode 33 provided on the surface thereof. Accordingly, the protrusion 32 is preferably formed such that its tip (the portion farthest from the current collector film 31) is a surface, and more preferably, its tip is a surface parallel to the surface of the current collector film 31. The When the tip of the protrusion 32 becomes a surface, the tip surface reliably supports the separator 14, so that the volume of the electrolyte holding portion is held substantially the same throughout the lifetime of the electricity storage device 1. Further, the tip of the protrusion 32 does not penetrate the separator 14 to short-circuit the positive and negative electrodes, and the product yield of the electricity storage device 1 is not reduced.
  • the protrusion 32 is not particularly limited in shape as long as the tip is a surface, and can be formed in various shapes. However, in consideration of the stable support of the separator 14, it is preferable to form the negative electrode current collector 30 so that the cross-sectional shape in the thickness direction is a trapezoidal shape or a pseudo-trapezoidal shape.
  • the pseudo trapezoidal shape is a shape in which the cross section in the thickness direction is almost a trapezoid, and the side (hereinafter referred to as “the upper side”) in contact with the surface of the current collecting film 31 rather than the side farther from the current collecting film 31 (hereinafter referred to as “upper side”).
  • the lower side is long and the upper side is not slightly parallel to the lower side.
  • the angle formed by the extension line on the upper side and the extension line on the lower side is about several degrees. Further, at least a part of the upper side in the cross section in the thickness direction may include a curve. Even if it is a pseudo trapezoid shape, the above-described effects can be obtained if the separator 14 can be supported by the surface.
  • FIG. 8 is a longitudinal sectional view schematically showing the configuration of the negative electrode current collector 35 of still another embodiment.
  • the protrusion 36 in the negative electrode current collector 35, the protrusion 36 has a triangular cross-sectional shape in the thickness direction, and the tip of the protrusion 36 has a sharp point. If the tip of the protrusion 36 is a point, at least a part of the tip may enter the separator 14 and possibly penetrate the separator 14. In addition, the tip of the protrusion 36 may penetrate the separator 14 to short-circuit the positive and negative electrodes, which may reduce the product yield of the electricity storage device 1.
  • the occupied volume of the negative electrode current collector 30 is a value obtained by multiplying the surface area of the current collector film 31 in the thickness direction by the thickness t of the negative electrode current collector 30.
  • the thickness t of the negative electrode current collector 30 refers to the length from the top of the protrusion 32 formed on one surface of the current collector film 31 to the top of the protrusion 32 formed on the other surface.
  • the ratio of the electrolyte holding portion to the occupied volume of the negative electrode current collector 30 to 30% or more, for example, the height of the protrusion 32, the total area of the surface formed at the tip of the protrusion 32, What is necessary is just to adjust a space
  • the height of the protrusion 32 refers to the length from the surface of the current collecting film 31 to the top of the protrusion 32.
  • the negative electrode current collector 30 can be manufactured, for example, by subjecting the current collector film 31 to mechanical processing and forming a plurality of protrusions 32 on the surface of the current collector film 31 in the thickness direction.
  • the mechanical processing is, for example, press processing or roller processing.
  • the negative electrode current collector 30 can also be obtained by subjecting the current collecting film 31 to surface processing such as polishing, etching, patterning, plating treatment (electrolytic plating, electroless plating, electrodeposition plating, etc.), and fine particle spraying treatment. Can be obtained.
  • a copper foil, a nickel foil or the like can be used for the current collecting film 31, for example.
  • the negative electrode 33 is preferably formed so as to follow the shape of the surface of the negative electrode current collector 30, and the shape of the protrusion 32 is preferably reproduced on the surface of the negative electrode 33.
  • the thickness of the negative electrode 33 needs to be sufficiently thin with respect to the height of the protrusion 32 existing on the surface of the negative electrode current collector 30.
  • the height of the protrusion 32 is preferably at least twice the thickness of the negative electrode 33, more preferably at least five times the thickness of the negative electrode 33, and further preferably 5 to 10 times.
  • FIG. 9 is a longitudinal sectional view schematically showing the configuration of the negative electrode laminate 40.
  • the negative electrode laminate 40 includes a negative electrode 41 and a negative electrode current collector 42.
  • the negative electrode current collector 42 includes a current collector film 43 and a protrusion 44.
  • the height of the protrusion 44 is less than twice the film thickness of the negative electrode 41. Since the negative electrode 41 is formed not only on the front surface of the protrusion 44 but also on the side surface of the protrusion 44, the space between the adjacent protrusions 44 is particularly narrowed.
  • the space of the electrolyte holding portion to be formed due to the presence of the protrusion 44 becomes extremely small, and the amount of electrolyte solution that can be held by the negative electrode current collector 42 is reduced.
  • the protrusions 32 are formed on both surfaces in the thickness direction.
  • the present invention is not limited thereto, and a plurality of protrusions 32 may be formed only on the surface of the negative electrode current collector 30 that contacts the separator 14. . In that case, the thin film negative electrode 33 may be provided only on the surface on which the protrusion 32 is formed.
  • precharging the negative electrode 12 with an amount of electricity means charging the negative electrode 12 with an amount of electricity and storing the lithium in the negative electrode active material prior to the fabrication (assembly) of the electricity storage device 1. . This is because the negative electrode 12 immediately after the production of the electricity storage device 1 has an irreversible capacity.
  • the irreversible capacity refers to a capacity corresponding to a part of the electric capacity charged in the negative electrode 12 that is consumed by a side reaction other than the occlusion / release reaction of lithium contributing to the charge / discharge reaction of the negative electrode active material. That is, the irreversible capacity is a capacity that cannot be reversibly discharged despite being charged, and is well known to be observed only in the first charge / discharge.
  • a known method can be employed, and examples thereof include a mechanical charging method, an electrochemical charging method, a chemical charging method, and the like.
  • the mechanical charging method for example, charging is performed by mechanically bringing a material (such as lithium metal) having a lower potential than the negative electrode active material into contact with the negative electrode active material. More specifically, for example, a predetermined amount of metallic lithium is attached to the negative electrode 12 surface, or a metallic lithium film is directly formed on the negative electrode 12 surface by a vacuum process such as vapor deposition, or a release-treated plastic. The metal lithium produced on the substrate is transferred to the surface of the negative electrode 12 and then charged.
  • a material such as lithium metal
  • the negative electrode 12 is heated to accelerate the progress of the charging reaction, thereby shortening the time required for the charging reaction. Is also possible.
  • the negative electrode 12 and the counter electrode are immersed in an electrolytic solution, and a current is passed between the negative electrode 12 and the counter electrode, whereby the negative electrode 12 is charged.
  • metallic lithium can be used as the counter electrode.
  • the electrolytic solution for example, a non-aqueous solvent in which a lithium salt is dissolved can be used.
  • a compound containing lithium ions such as butyl lithium is dissolved in an organic solvent, and this solution is brought into contact with the negative electrode 12 to cause a chemical reaction, thereby charging the negative electrode 12.
  • the contact between the lithium ion-containing compound solution and the negative electrode 12 is performed, for example, by immersing the negative electrode 12 in the solution.
  • the negative electrode 12 is taken out after charging, and the solvent, electrolyte salt, and other compounds used for the charging treatment, which are attached to the surface of the negative electrode 12, are removed by washing. There is a need. In addition, the charging process itself takes a long time. Further, since the negative electrode 12 after charging is close to the lithium potential and has a very low potential and becomes highly reactive, the surface of the negative electrode 12 may be deteriorated during cleaning of the negative electrode 12 after charging. On the other hand, in the mechanical charging method, since only lithium is brought into contact with the negative electrode 12, there is no need for cleaning and the required time is short. There is no deterioration of the surface of the negative electrode 12.
  • the mechanical charging method is preferable from the viewpoint of manufacturing and characteristics.
  • a method in which metallic lithium is directly formed on the surface of the negative electrode 12 by a thin film forming process such as vapor deposition is most desirable.
  • the negative electrode 12 in the electricity storage device of the present invention is a thin film negative electrode having a thickness of 10 ⁇ m or less
  • the lithium to be charged also needs to be controlled with a thin film having a thickness of 10 ⁇ m or less, and in some cases, 5 ⁇ m or less.
  • a mechanical charging method by a thin film forming process such as vapor deposition is desirable from the viewpoint of thickness controllability and processing time.
  • the negative electrode 12 when the negative electrode 12 is charged with a predetermined amount of electricity, the negative electrode 12 directly formed on the negative electrode current collector 13 without containing a binder in the electricity storage device 1 of the present invention is effective.
  • the reason for this will be described below.
  • the negative electrode 12 when lithium is deposited on the negative electrode 12 by vapor deposition and mechanical charging is performed, since the melting point of lithium is 179 ° C., the negative electrode 12 is exposed to lithium heated to a high temperature of at least about 179 ° C. Will be.
  • most of the resin materials used as the main component of the binder are rich in chemical reactivity, such as lithium, and heated to a temperature of around 179 ° C.
  • the negative electrode 12 is formed directly on the surface of the negative electrode current collector 13 without containing a binder, a mechanical charging method using a thin film forming method such as vapor deposition can be applied, It is very effective.
  • the negative electrode current collector 13 those used for the negative electrode current collector in various power storage devices can be used, and among them, those used for the negative electrode current collector of the lithium ion battery can be preferably used.
  • a negative electrode current collector include a metal foil made of a metal such as copper or nickel. Among these, copper foil is preferable in consideration of workability and the like.
  • Examples of the form of the negative electrode current collector plate 13 include a film shape with a smooth surface, a film shape with a roughened surface, a mesh shape made of fine metal fibers, and a porous film shape.
  • the surface roughness (Ra) of the negative electrode current collector plate 13 is preferable in consideration of adhesion to the negative electrode 12, output characteristics of the electricity storage device 1, and the like. Is about 1 to 2 ⁇ m, preferably 5 or more, more preferably 10 or more.
  • the layered positive electrode 10 is provided so that one surface in the thickness direction is in contact with the separator 14 and the other surface is in contact with the positive electrode current collector 11, and includes a positive electrode active material. Furthermore, the positive electrode 10 may contain an ion conduction aid, an electron conduction aid, a binder, and the like together with the positive electrode active material.
  • the positive electrode active material a material capable of reversibly adsorbing and desorbing at least anions during charge / discharge can be used.
  • the positive electrode active material used for an electric double layer capacitor, the positive electrode active material used for an electrochemical capacitor, etc. are mentioned.
  • the material used for the positive electrode active material may be capable of reversibly adsorbing and desorbing cations.
  • Activated carbon the organic compound which can be oxidized / reduced, etc. can be used preferably.
  • activated carbon activated carbon having a high specific surface area is preferable. For example, by carbonizing a carbon material (such as coconut shell, organic resin, petroleum pitch) in an inert gas such as nitrogen gas at a temperature of 900 to 1000 ° C., and then introducing water vapor into the system, Activated carbon having an extremely high specific surface area of up to about 2000 m 2 / g can be obtained.
  • the shape of the activated carbon is not particularly limited, and examples thereof include a powder shape, a fiber shape, and a flake shape (or scale shape).
  • Examples of the organic compound capable of oxidation / reduction include organic compounds having radicals, organic compounds having ⁇ -electron conjugated clouds, and indole organic compounds.
  • Examples of the organic compound having a radical include an organic compound having at least one radical selected from a nitroxy radical, a boron radical, and an oxygen radical in the molecule. Specific examples of such organic compounds include, for example, 2,2,6,6-tetramethylpiperidine-1-oxyl, 2,2,5,5-tetramethyl-3-imidazolium-1-loxy and the like Examples thereof include nitroxy radical-containing compounds, quinones such as quinone and benzoquinone.
  • Examples of the organic compound having a ⁇ electron conjugated cloud include an organic compound having a structure represented by the following general formula (1).
  • R 1 to R 4 each independently represents a chain aliphatic group, a cyclic aliphatic group, a hydrogen atom, a hydroxyl group, a cyano group, an amino group, a nitro group, or a nitroso group.
  • R 5 and R 6 each independently represent a hydrogen atom, a chain aliphatic group or a cyclic aliphatic group.
  • the chain aliphatic group and cycloaliphatic group represented by R 1 to R 6 are at least one selected from the group consisting of oxygen atom, nitrogen atom, sulfur atom, silicon atom, phosphorus atom, boron atom and halogen atom. It may contain seed atoms.
  • the organic compound which has a structure represented by following General formula (2) is mentioned.
  • R 1 ⁇ R 6 in the general formula (2) are the same as R 1 ⁇ R 6 in the general formula (1).
  • the organic compound which has a structure represented by following General formula (3) is mentioned.
  • X 1 to X 4 each independently represent a sulfur atom, an oxygen atom, a selenium atom or a tellurium atom.
  • R 7 and R 8 each independently represents a divalent chain aliphatic group or a divalent cyclic aliphatic group.
  • the divalent chain aliphatic group and divalent cyclic aliphatic group represented by R 7 to R 8 are composed of an oxygen atom, a nitrogen atom, a sulfur atom, a silicon atom, a phosphorus atom, a boron atom, and a halogen atom. It may contain at least one atom selected from the group.
  • the monovalent or divalent chain aliphatic group and cyclic aliphatic group represented by R 1 to R 8 are oxygen atoms, nitrogen atoms in the molecular chain.
  • You may have atoms, such as an atom, a sulfur atom, and a phosphorus atom.
  • “may have an atom such as an oxygen atom, a nitrogen atom, a sulfur atom, or a silicon atom” means that it may have a group containing at least one of these atoms.
  • Examples of the group having a nitrogen atom include an amino group, an imino group, a cyano group, and a nitro group.
  • Examples of the group having an oxygen atom include an alkoxy group, a hydroxyl group, an alkyl group having a hydroxyl group, and an oxo group.
  • Examples of the group having a sulfur atom include a sulfo group, a sulfonyl group, a sulfonic acid group, a thiocarbonyl group, a sulfamoyl group, and an alkylsulfonyl group.
  • Examples of the group having a silicon atom include a silyl group. Further, at least one of these atoms may be incorporated in the middle of a saturated or unsaturated carbon chain in an alkyl group, an alkenyl group or the like.
  • Boron and halogen atoms can be bonded to various substituents.
  • the boron atom and the halogen atom may be directly substituted with a monovalent or divalent chain aliphatic group or cyclic aliphatic group represented by R 1 to R 8 .
  • indole organic compounds examples include indole trimers such as 5-cyanoindole, and derivatives thereof.
  • a positive electrode active material used for an electrochemical capacitor the material which has the pseudo
  • a positive electrode active material include metal oxides such as ruthenium oxide, iridium oxide, and manganese oxide, and nanocarbon materials such as nanogate carbon and carbon nanotubes.
  • a positive electrode active material can be used individually by 1 type or in combination of 2 or more types as needed.
  • the ion conduction aid is used for improving ion conductivity, for example.
  • the ion conduction aid include, for example, a solid electrolyte such as polyethylene oxide, a gel electrolyte containing polymethyl methacrylate, and the like.
  • the electron conduction aid is used, for example, to improve electron conductivity.
  • Specific examples of the electron conduction aid include carbon materials such as carbon black, graphite, and acetylene black, and conductive polymers such as polyaniline, polypyrrole, and polythiophene.
  • the binder is used, for example, to improve the binding property of the positive electrode active material.
  • binder examples include polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-polytetrafluoroethylene, polytetrafluoroethylene, polyethylene, polyimide, polyacrylic acid, carboxymethylcellulose, acrylonitrile rubber, and butadiene. Examples thereof include rubber and styrene butadiene rubber.
  • the thickness of the positive electrode 10 (hereinafter referred to as “positive electrode thickness”) is not particularly limited, but for example, in view of electrolyte retention, it is preferably at least 5 times the thickness of the negative electrode 12 (hereinafter referred to as “negative electrode thickness”). More preferably, it is 10 times or more the thickness of the negative electrode.
  • the upper limit of the positive electrode thickness to the negative electrode thickness is about 50 to 100 times. This is because, if the thickness of the positive electrode is too thick, such as about 50 to 100 times the thickness of the negative electrode, the storage capacity of the electricity storage device becomes negative electrode regulation, resulting in a decrease in capacity.
  • the negative electrode 12 is directly formed on the surface of the negative electrode current collector 13 to reduce the thickness of the negative electrode. Therefore, there is a possibility that the electrolyte retention in the negative electrode 12 may be reduced. In order to compensate for this, it is preferable to increase the thickness of the positive electrode. Specifically, it is desirable that the thickness of the negative electrode is about 2 to 10 ⁇ m and the thickness of the positive electrode is about 20 to 100 ⁇ m, which is 10 times or more. More preferably, the thickness of the negative electrode is 2 to 5 ⁇ m, and the thickness of the positive electrode is preferably about 20 to 50 ⁇ m, which is 10 times or more.
  • the layered positive electrode current collector 11 is provided so that one surface in the thickness direction is in contact with the positive electrode 10 and the other surface is in contact with the case 18.
  • a general material used for a positive electrode current collector plate of a lithium ion battery can be used, and examples thereof include aluminum and stainless steel.
  • the positive electrode current collector 11 is preferably formed in a film shape or a sheet shape. Further, the surface form of the positive electrode current collector 11 may be smooth or roughened.
  • the internal structure of the positive electrode current collector 11 may be a mesh body containing a metal fiber, a porous body, or the like.
  • the separator 14 is provided so as to be sandwiched between the positive electrode 10 and the negative electrode 12.
  • the separator 14 can be a separator used for lithium ion batteries, electric double layer capacitors, and the like, and examples thereof include microporous films such as polypropylene and polyethylene, and nonwoven fabrics.
  • the separator 14 is supported or impregnated with an electrolyte as required.
  • the electrolyte is not particularly limited, and examples thereof include a supporting salt (electrolyte salt), a liquid electrolyte (or nonaqueous electrolytic solution) obtained by dissolving the supporting salt in a nonaqueous solvent, a gel electrolyte, and a solid electrolyte.
  • the supporting salt can be appropriately selected from known supporting salts according to the type of the electricity storage device 1 and used.
  • a salt containing lithium and an anion can be used.
  • the anion is not particularly limited as long as it forms a salt with lithium.
  • Examples thereof include phosphate anion (PF 6 ⁇ ), bis (trifluoromethanesulfonyl) imide anion, and bis (perfluoroethylsulfonyl) imide anion.
  • a supporting salt can be used individually by 1 type, or may be used in combination of 2 or more types as needed.
  • the non-aqueous solvent in which the supporting salt is dissolved can be appropriately selected from known non-aqueous solvents according to the type of the electricity storage device 1 and used.
  • the electricity storage device 1 is a lithium ion battery, a non-aqueous electric double layer capacitor or the like
  • examples of the non-aqueous solvent include ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, ⁇ -butyrolactone, Tetrahydrofuran, dioxolane, sulfolane, dimethylformamide, acetonitrile and the like can be used.
  • a non-aqueous solvent may be used individually by 1 type, or may be used in combination of 2 or more type.
  • the gel electrolyte is a gelled liquid electrolyte.
  • the gelation of the liquid electrolyte is performed, for example, by adding a gelling agent to the liquid electrolyte.
  • a gelling agent those commonly used in this field can be used, and examples thereof include a polymer containing polyacrylonitrile, an acrylate compound or a methacrylate compound as a monomer component, and a copolymer of ethylene and acrylonitrile.
  • the solid electrolyte is a solid electrolyte.
  • the solid electrolyte examples include Li 2 S—SiS 2 , Li 2 S—B 2 S 5 , Li 2 S—P 2 S 5 —GeS 2 , a mixture of sodium and alumina (Al 2 O 3 ), and amorphous.
  • examples include polyethers, polyethers having a low phase transition temperature (Tg), amorphous vinylidene fluoride-6-propylene copolymer, and heterogeneous polymer blend polyethylene oxide.
  • the electricity storage device 1 may be configured by arranging only the electrolyte between the positive electrode 10 and the negative electrode 12 without using the separator 14.
  • the power storage device 1 includes a spacer 17, a negative electrode current collector 13, a negative electrode 12, a separator 14, a positive electrode 10, and a positive electrode current collector 11 that are stacked in this order in the thickness direction. 18, and the sealing plate 15 and the case 18 are caulked through the gasket 16.
  • the spacer 17 is not necessary. That is, whether or not to provide the spacer 17 may be appropriately selected according to the contact pressure of each member.
  • the power storage device of the present invention includes, for example, a power source such as a hybrid vehicle, various electric / electronic devices (particularly mobile communication devices, portable electronic devices such as notebook PCs and mobile phones), thermal power generation, wind power generation, fuel cell power generation, etc. It can be suitably used as a power storage device for power generation leveling, an emergency power storage system for ordinary homes and apartment buildings, a power source for a midnight power storage system, an uninterruptible power supply, and the like.
  • a power source such as a hybrid vehicle
  • various electric / electronic devices particularly mobile communication devices, portable electronic devices such as notebook PCs and mobile phones
  • thermal power generation wind power generation
  • fuel cell power generation etc.
  • It can be suitably used as a power storage device for power generation leveling, an emergency power storage system for ordinary homes and apartment buildings, a power source for a midnight power storage system, an uninterruptible power supply, and the like.
  • an electricity storage device for a mobile phone or the like will be described.
  • FIG. 10 is a schematic perspective view of a mobile phone 100 using the power storage device of the present invention as a power source.
  • the mobile phone 100 includes a display unit 166 such as a liquid crystal panel and an input unit 168, and an electronic control circuit unit (not shown) and a housing 160 provided with the input unit 168, and
  • the power storage device 150 of the present invention is installed as a power supply unit.
  • the control circuit unit controls, for example, the charge amount (SOC) of the power storage device and the display on the panel. For example, the voltage at the time of charge of an electrical storage device is controlled.
  • SOC charge amount
  • the power storage device 150 the power storage device of the present invention and a conventional power storage device may be used in combination.
  • conventional power storage devices include lithium ion batteries, nickel metal hydride storage batteries, capacitors, and fuel cells. Since the electricity storage device of the present invention can be reduced in size and thickness, the space required for installing the electricity storage device can be reduced, and the mobile phone can be reduced in size and thickness. Since the electricity storage device of the present invention can be charged at high speed, the charging time can be shortened. Since the electricity storage device of the present invention has a high output and a high capacity, it is possible to improve the performance such as extending the continuous talk time of the mobile phone.
  • FIG. 11 is a schematic perspective view of a notebook PC 200 using the power storage device of the present invention as a power source.
  • the notebook PC 200 includes a housing 260 including a display unit 266 such as a liquid crystal panel and a key operation unit 210, and an electronic control circuit unit (not shown) including a CPU and the like in the housing 260.
  • a power storage device 270 of the present invention is installed as a cooling fan (not shown) and a power supply unit.
  • the power storage device of the present invention and a conventional power storage device may be used in combination.
  • Examples of conventional power storage devices include lithium ion batteries, nickel metal hydride storage batteries, capacitors, and fuel cells. Since the electricity storage device of the present invention can be reduced in size and thickness, the space required for installing the electricity storage device can be reduced, and the notebook PC can be reduced in size and thickness. Since the electricity storage device of the present invention can be charged at high speed, the charging time can be shortened. Since the electricity storage device of the present invention has a high output and a high capacity, the notebook PC can be used for a long time or can be started at a high speed.
  • FIG. 12 is a diagram showing a configuration of a hybrid vehicle 300 using the electricity storage device of the present invention.
  • the hybrid vehicle 300 includes the engine 302, a plurality of motors 303, 304, and 305, inverters 306, 307, and 308 connected to the motor 302, and a power supply unit that supplies power.
  • Power storage device 309 and a controller 310 for controlling the entire system.
  • the motor 303 is a motor for starting the engine 302 or assisting departure of the vehicle, and also functions as a generator.
  • the motor 304 is a motor for driving a vehicle, and the motor 305 is a motor for steering (power steering).
  • the motor 303 Due to the discharge (power supply) of the electricity storage device 309, the motor 303 is driven to assist in starting or starting the engine 302, and the motor 305 connected to the hydraulic device 311 is driven at high speed.
  • the power storage device 309 is charged by converting the driving force of the engine 302 into electric power using the motor 303 as a generator.
  • the power storage device of the present invention and a conventional power storage device may be used in combination. Examples of conventional power storage devices include lithium ion batteries, nickel metal hydride storage batteries, capacitors, and fuel cells. Since the electricity storage device of the present invention can be reduced in size and thickness, the weight of an automobile can be reduced.
  • the space required for installing the power storage device can be reduced, and a larger storage space and seat space can be secured. Since the electricity storage device of the present invention can be charged and discharged at high speed and has high output and high capacity, it can cope with various driving modes and contribute to improvement in fuel efficiency of an automobile.
  • Example 1 A coin-type electricity storage device similar to that shown in FIG. 1 was produced by the following procedure. (1) Production of positive electrode 100 mg of activated carbon powder (specific surface area 1700 m 2 / g, number average particle diameter 2 ⁇ m) as a positive electrode active material and 20 mg of acetylene black as an electron conduction aid were uniformly mixed. A positive electrode mixture slurry was prepared by adding 20 mg of polyvinylpyrrolidone and 800 mg of methanol to this mixture.
  • the positive electrode mixture slurry was applied on a positive electrode current collector (thickness 15 ⁇ m) made of an aluminum foil, and then vacuum-dried to form a layered positive electrode on the surface of the aluminum foil.
  • the positive electrode laminate comprising the positive electrode current collector and the positive electrode was punched and cut into a disk shape having a diameter of 13.5 mm.
  • the coating weight of the positive electrode active material was 6.1 mg / cm 2
  • the positive electrode thickness was 45 ⁇ m.
  • the activated carbon powder which is a positive electrode active material is obtained by carbonizing a phenol resin-based carbon material in nitrogen gas, and then performing activation treatment by introducing water vapor.
  • an electric double layer capacitor obtained by using this positive electrode laminate and using a laminate having exactly the same structure as a counter electrode (negative electrode) can be used in a range of a single electrode potential of 0 to 1 V (0 to 2 V as an electric storage device).
  • the electricity storage device capacity was 0.08 mAh.
  • a copper foil (specific surface area 11.6, arithmetic average surface roughness (Ra) 2.0 ⁇ m, thickness 43 ⁇ m) was used for the negative electrode current collector.
  • a negative electrode (thickness 6 ⁇ m, specific surface area 4.2) made of a thin film of silicon oxide (SiOx) was formed on the copper foil by electron beam heating vapor deposition.
  • the specific surface area and arithmetic average surface roughness were measured using a laser microscope (trade name: Ultradeep shape measuring microscope VK-855, manufactured by Keyence Corporation).
  • the thickness of the negative electrode current collector and the negative electrode was measured with a scanning electron microscope (SEM).
  • SEM scanning electron microscope
  • the negative electrode laminated body which consists of a negative electrode collector and a negative electrode was obtained.
  • the negative electrode thickness was adjusted by adjusting the deposition time.
  • the conditions for electron beam heating vapor deposition are as follows.
  • silicon metal with a purity of 99.9999% manufactured by Kojundo Chemical Laboratory Co., Ltd.
  • oxygen gas with a purity of 99.7% manufactured by Nippon Oxygen Co., Ltd.
  • the degree of vacuum was adjusted to 3 ⁇ 10 ⁇ 3 Pa.
  • the acceleration voltage of the electron beam irradiated to the vapor deposition source was 8 kV, and the emission was 500 mA.
  • a separator (thickness 20 ⁇ m) made of a porous polyethylene sheet is formed by punching and cutting a negative electrode laminate produced by the same method as above into a disc shape having a diameter of 13.5 mm and a counter electrode made of a lithium metal plate (thickness 300 ⁇ m).
  • a coin-type electricity storage device was manufactured by facing each other. This electricity storage device was charged and discharged three times. At this time, the current value was 0.5 mA, the upper limit voltage was 1.5 V, and the lower limit voltage was 0 V.
  • the negative electrode immediately after fabrication obtained above does not contain lithium, it is in a completely discharged state, that is, in a state of SOC (State of Charge) 0%.
  • the SOC of the negative electrode is an index that represents the state of charge of the single negative electrode, not the entire power storage device, and represents the percentage of the charge amount with respect to the full charge amount as a percentage with the capacity when the negative electrode is fully charged being 100%. Value. Therefore, the fully discharged SOC is 0%, and the fully charged SOC is 100%.
  • a 4.5 ⁇ m-thick lithium metal layer was formed on the negative electrode surface obtained above by an evaporation method, and the SOC of the negative electrode was adjusted to 50%.
  • the charge amount of the negative electrode when charged at 0.2 CA (5-hour rate) with respect to the negative electrode capacity in a potential range of 0 to 1.5 V with respect to lithium is defined as SOC 100% (full charge).
  • the SOC of the negative electrode was determined based on the above.
  • the lithium metal deposited on the surface of the negative electrode is absorbed by the negative electrode without being immersed in the electrolyte, and the negative electrode is charged (lithium charging).
  • the lithium charge amount is an amount corresponding to the amount of charge charged to 50% of the reversible capacity (SOC 50%).
  • the negative electrode with 50% SOC had a thickness of 9 ⁇ m. After the SOC adjustment, the negative electrode laminate was punched and cut into a disk shape having a diameter of 13.5 mm.
  • Example 2 An electrolytic copper foil (specific surface area 11.6, arithmetic average surface roughness (Ra) 1.8 ⁇ m, thickness 43 ⁇ m) was used for the negative electrode current collector.
  • the negative electrode laminated body which consists of a negative electrode collector and a negative electrode was obtained.
  • RF sputtering was performed as follows. A 10-inch diameter molten silicon target (silicon purity 99.99%) was used, the distance between the target and the substrate was 7 cm, and argon 50 sccm was introduced. The vacuum atmosphere pressure was 1.1 Pa, the applied power was 1 kW, and the film formation time was 5 hours.
  • the reversible capacity capable of charge / discharge is 2.1 mAh (capacity per unit area: 1.5 mAh / cm 2 ), and the irreversible capacity does not contribute to charge / discharge.
  • a 4 ⁇ m-thick lithium metal layer was formed on the negative electrode surface obtained above by a vapor deposition method, and the SOC of the negative electrode was adjusted to 50%. The lithium metal deposited on the surface of the negative electrode is absorbed by the negative electrode without being immersed in the electrolyte, and the negative electrode is charged (lithium charging).
  • this lithium charge amount is an amount corresponding to the charge electricity amount charged to SOC 50%.
  • the SOC 50% negative electrode thus obtained had a film thickness of 4 ⁇ m.
  • An electricity storage device was produced in the same manner as in Example 1 except that this negative electrode laminate of the negative electrode and the negative electrode current collector was used.
  • Comparative Example 1 As the negative electrode active material, SiO particles (manufactured by High Purity Science Laboratory Co., Ltd.) were used, and those pulverized and sized to a particle size of 44 ⁇ m or less with an automatic mortar were used as the negative electrode active material. This negative electrode active material, graphite (electron conduction aid), and polyacrylic acid (binder) were mixed in a weight ratio of 45:40:15, respectively, to obtain a negative electrode mixture. This negative electrode mixture was pressure-bonded to a 100 ⁇ m-thick nickel mesh as a negative electrode current collector to form a 75 ⁇ m-thick negative electrode (mixture layer).
  • capacitance confirmation and the charging process by the electrochemical charging method were performed as follows.
  • the negative electrode obtained above and a counter electrode made of lithium metal (thickness: 300 ⁇ m) were opposed to each other with a separator (thickness: 20 ⁇ m) made of a porous polyethylene sheet, to produce a coin-type electricity storage device.
  • this electrical storage device was charged / discharged 3 times.
  • the current value was 0.5 mA
  • the upper limit voltage was 1.5 V
  • the reversible capacity capable of charge / discharge was 14 mAh
  • the irreversible capacity not contributing to charge / discharge was 9 mAh.
  • the coin-type electricity storage device After charging to 50% of the reversible capacity (SOC 50%), the coin-type electricity storage device was disassembled, and a negative electrode laminate composed of a negative electrode current collector and a negative electrode was taken out. An electricity storage device was produced in the same manner as in Example 1 except that this negative electrode laminate was used.
  • Comparative Example 2 A negative electrode having a thickness of 50 ⁇ m containing a binder was formed on the surface of the nickel mesh (negative electrode current collector) in the same manner as in Comparative Example 1 except that the negative electrode thickness was changed from 75 ⁇ m to 50 ⁇ m.
  • capacitance confirmation and the charge process were performed by the method similar to the comparative example 1.
  • the coin-type electricity storage device After charging to 50% of reversible capacity (SOC 50%), the coin-type electricity storage device was disassembled, and only the negative electrode laminate composed of the negative electrode current collector and the negative electrode was taken out. An electricity storage device was produced in the same manner as in Example 1 except that this negative electrode laminate was used.
  • Comparative Example 3 The same negative electrode as Comparative Example 2 was charged by a mechanical charging method. That is, a Li metal layer having a thickness of 38 ⁇ m was formed on the negative electrode by vapor deposition. In addition to the irreversible capacity of the negative electrode, this layer contains an amount of Li corresponding to the amount of electricity that can be charged to 50% SOC of the reversible capacity of the negative electrode. After the deposition of Li, the entire surface of the negative electrode was colored silver, Li deposition was confirmed, and the charging reaction of Li to the negative electrode did not occur completely.
  • the electricity storage devices of Examples 1 and 2 and Comparative Examples 1 and 2 were evaluated for charge / discharge capacity.
  • the electricity storage devices of Examples 1 and 2 and Comparative Examples 1 and 2 have a positive electrode capacity of 0.08 mAh, and use a negative electrode having a sufficiently excessive amount of reversible capacity with respect to the positive electrode capacity. Is big enough. Therefore, the theoretical charge / discharge capacity of these electricity storage devices is 0.08 mAh.
  • the charge / discharge capacity is evaluated by performing constant current charge / discharge at a current value of 0.5 mA, 4 mA, or 12 mA to obtain a charge upper limit voltage of 3.75 V and a discharge lower limit voltage of 2.75 V. It took as 1 minute.
  • the charging pause time is the time from the end of charging until the start of the next discharge.
  • the discharge pause time is the time from the end of discharge until the start of the next charge. This charge / discharge was repeated three times, and the third discharge capacity was defined as the charge / discharge capacity. The evaluation results are shown in Table 1.
  • the current value was 0.5 mA, 4 mA, It was confirmed that even if the current was increased to 12 mA, most of the charge / discharge electricity could be maintained. In other words, it has been possible to provide a power storage device having a higher output than before.
  • the electrical storage device using the negative electrode containing the organic binder of Comparative Example 3 lithium could not be occluded in advance by a vapor deposition method.
  • the power storage devices of Examples 1 and 2 were found to be excellent in workability because lithium could be occluded in the negative electrode by vapor deposition before assembly.
  • the electricity storage device of Example 2 (negative electrode thickness 4 ⁇ m) has a larger discharge capacity at a current value of 12 mA, and a higher output electricity storage device is obtained. It was. This is considered to be because the thickness of the negative electrode in the electricity storage device of Example 2 was 4 ⁇ m, which was thinner than the thickness of the negative electrode of the electricity storage device in Example 1. Therefore, it was found that the thickness of the negative electrode is preferably 5 ⁇ m or less.
  • the positive electrode active material and the negative electrode active material It is possible to increase the energy density as compared with the conventional power storage device using activated carbon for both.
  • the negative electrode used in the electricity storage device of the present invention is a thin film having a thickness of 10 ⁇ m or less. Therefore, according to the present invention, it is possible to simultaneously achieve high capacity and downsizing of the electricity storage device.
  • Example 3 an electricity storage device was produced in the same manner as in Example 1 except that the positive electrode laminate was used.
  • the positive electrode active material constituting the positive electrode an organic compound polymer having a ⁇ -conjugated electron cloud (hereinafter referred to as “ ⁇ -conjugated polymer”), which is a homopolymer of monomer units represented by the chemical structural formula (4), was used.
  • This ⁇ -conjugated polymer was synthesized by dehydrating and condensing polyvinyl alcohol and a compound having a molecular structure represented by the chemical structural formula (5) in which a carboxyl group was introduced into tetrathiafulvalene.
  • This ⁇ -conjugated polymer had a number average molecular weight of about 15000 and a theoretical maximum capacity of 200 mAh / g.
  • ⁇ -conjugated polymer and 100 mg of acetylene black were uniformly mixed, and 25 mg of polytetrafluoroethylene was further added and mixed to prepare a positive electrode mixture.
  • This positive electrode mixture was pressure-bonded onto a positive electrode current collector made of an aluminum wire mesh and vacuum-dried. This was punched and cut into a disk shape having a diameter of 13.5 mm to produce a laminate of a positive electrode and a positive electrode current collector.
  • the coating weight of the positive electrode active material was 0.5 mg / cm 2 per unit area of the positive electrode, the positive electrode thickness was 90 ⁇ m, and the positive electrode theoretical capacity was 0.14 mAh.
  • Example 4 An electricity storage device was produced in the same manner as in Example 1 except that the following positive electrode laminate was used.
  • the positive electrode active material constituting the positive electrode an organic compound polymer having a radical that is a homopolymer of the monomer unit represented by the chemical structural formula (6) (hereinafter referred to as “radical polymer”) was used.
  • This radical polymer was synthesized by radical polymerization of a monomer compound represented by the chemical structural formula (7) and then oxidizing a hydrogen atom bonded to a nitrogen atom.
  • This radical polymer had a number average molecular weight of about 100,000 and a theoretical maximum capacity of 110 mAh / g.
  • a positive electrode mixture 37.5 mg of radical polymer and 100 mg of acetylene black were uniformly mixed, and 25 mg of polytetrafluoroethylene was further added and mixed to prepare a positive electrode mixture.
  • This positive electrode mixture was pressure-bonded onto a positive electrode current collector made of an aluminum wire mesh and vacuum-dried. This was punched and cut into a disk shape having a diameter of 13.5 mm to produce a laminate of a positive electrode and a positive electrode current collector.
  • the coating weight of the positive electrode active material was 0.5 mg / cm 2 per unit area of the positive electrode, the positive electrode thickness was 90 ⁇ m, and the positive electrode theoretical capacity was 0.08 mAh.
  • the charge / discharge capacity evaluation was performed on the electricity storage devices of Examples 3 to 4.
  • the charge / discharge capacity is evaluated by performing constant current charge / discharge at a current value of 0.5 mA, 4 mA, or 12 mA to obtain a charge upper limit voltage of 3.75 V and a discharge lower limit voltage of 2.75 V. It took as 1 minute.
  • the charging pause time is the time from the end of charging until the start of the next discharge.
  • the discharge pause time is the time from the end of discharge until the start of the next charge.
  • This charge / discharge was repeated three times, and the third discharge capacity was defined as the charge / discharge capacity.
  • Table 2 The evaluation results are shown in Table 2.
  • Example 5 the relationship between the thickness of the negative electrode and the thickness of the positive electrode was examined.
  • a negative electrode was produced by the following method.
  • a copper foil (specific surface area 11.6, surface roughness (Ra) 2.0 ⁇ m, thickness 43 ⁇ m) was used for the negative electrode current collector.
  • a negative electrode (thickness 6 ⁇ m, specific surface area 4.2) made of a thin film of silicon oxide (SiOx) was formed on the copper foil by electron beam heating vapor deposition.
  • the negative electrode laminated body which consists of a negative electrode collector and a negative electrode was obtained.
  • the negative electrode thickness was adjusted by adjusting the deposition time.
  • the conditions for electron beam heating vapor deposition are as follows.
  • Silicon metal with a purity of 99.9999% (manufactured by Kojundo Chemical Laboratory Co., Ltd.) is used as a vapor deposition source, and oxygen gas with a purity of 99.7% (manufactured by Nippon Oxygen Co., Ltd.) is introduced into the vacuum chamber and vacuum is applied.
  • the degree was adjusted to 3 ⁇ 10 ⁇ 3 P.
  • the acceleration voltage of the electron beam applied to the vapor deposition source was 8 kV, and the emission was 500 mA.
  • the molar ratio of Si and O in the negative electrode was 1: 0.6. From this, it was found that the x value of silicon oxide (SiOx) constituting the negative electrode was 0.6.
  • a separator (thickness 20 ⁇ m) made of a porous polyethylene sheet is formed by punching and cutting a negative electrode laminate produced by the same method as above into a disc shape having a diameter of 13.5 mm and a counter electrode made of lithium metal (thickness 300 ⁇ m).
  • the coin-type electricity storage device was manufactured by facing each other. This electricity storage device was charged and discharged three times. At this time, the current value was 0.5 mA, the upper limit voltage was 1.5 V, and the lower limit voltage was 0 V.
  • This charge / discharge confirmed that the reversible capacity capable of charge / discharge was 1.8 mAh (capacity per unit area: 1.3 mAh / cm 2 ), and the irreversible capacity not contributing to charge / discharge was 0.5 mAh.
  • the SOC of the negative electrode was adjusted as follows. That is, the negative electrode was mechanically charged, and then the SOC of the negative electrode was finely adjusted by electrochemical charging. Specifically, a lithium metal having a thickness of 2.6 ⁇ m corresponding to an irreversible capacity (0.5 mAh) was formed on the negative electrode surface of the negative electrode laminate obtained above by an evaporation method. Note that lithium deposited on the surface of the negative electrode was absorbed by the negative electrode without immersing the negative electrode in the electrolyte, and the irreversible capacity was charged in the negative electrode.
  • a coin-type electricity storage device is fabricated by punching and cutting a negative electrode laminate after mechanical charging into a disk shape having a diameter of 13.5 mm and a counter electrode made of lithium metal (thickness 300 ⁇ m) with a separator interposed therebetween. did. Then, the negative electrode was charged with a constant current of 0.5 mA until the SOC of the negative electrode reached 50% (charged electric charge 0.05 mAh). The same separator and electrolyte as those used in Example 1 were used. Thus, after charging until the SOC of the negative electrode reached 50%, the coin-type electricity storage device was disassembled to obtain a negative electrode with an SOC of 50%. The thickness of the negative electrode obtained at this time was 9 ⁇ m.
  • Positive electrode laminates (A-1) to (A-7) were produced.
  • the positive electrode thicknesses 45, 60, 70, 100, 125, 30, and 35 ⁇ m are blended ratios of acetylene black as an electron conduction aid with respect to 100 mg of activated carbon powder (specific surface area 1700 m 2 / g, average particle diameter 2 ⁇ m).
  • the electricity storage devices (A-1) to (A-7) were produced in the same manner as in Example 1. Was made.
  • charge / discharge capacity was evaluated for the electricity storage devices (A-1) to (A-7).
  • the evaluation of the charge / discharge capacity is a constant current charge / discharge of 4 mA or 12 mA, a charge upper limit voltage of 3.75 V, a discharge lower limit voltage of 2.75 V, a charge pause time until the start of the next discharge after the end of charge, and The discharge pause time from the end of discharge until the start of the next charge was 1 minute each.
  • This charge / discharge was repeated three times, and the third discharge capacity was defined as the charge / discharge capacity.
  • the thickness of the positive electrode was measured in the storage devices (A-1) to (A-5) in which the thickness of the positive electrode was 5 times or more the thickness of the negative electrode.
  • the electricity storage devices (A-6) and (A-7) having a thickness of less than 5 times the thickness of the negative electrode a high capacity of 0.08 mAh was obtained. From the above, it was found that the thickness of the positive electrode is preferably 5 times or more the thickness of the negative electrode.
  • the electricity storage devices (A-1) to (A-7) have a positive electrode capacity of 0.08 mAh, and the negative electrode capacity has a sufficiently excessive amount of reversible capacity relative to the positive electrode capacity. The capacity is 0.08 mAh.
  • the thickness of the positive electrode is equal to the thickness of the negative electrode. It was found that a capacity higher than that of the electricity storage devices (A-1) to (A-3), (A-6) and (A-7) of less than 10 times was obtained. The fact that a high capacity can be obtained even when charging / discharging with a large current means that the power storage device has a high capacity and excellent output characteristics.
  • the thickness of the positive electrode is more preferably 10 times or more the thickness of the negative electrode.
  • Example 6 the specific surface area of the negative electrode was examined. Using the following negative electrode laminates (B-1) to (B-3), electricity storage devices (B-1) to (B-3) were produced in the same manner as in Example 1.
  • the negative electrode laminate (B-1) was produced by the following method.
  • an electrolytic copper foil (specific surface area 11.6, arithmetic average surface roughness (Ra) 1.8 ⁇ m, thickness 43 ⁇ m) was used.
  • a negative electrode made of a silicon thin film was formed on the copper foil by RF sputtering.
  • the negative electrode laminated body which consists of a negative electrode collector and a negative electrode was obtained.
  • RF sputtering was performed as follows.
  • a 10-inch diameter molten silicon target (silicon purity 99%) was used, the distance between the target and the substrate was 7 cm, and argon was introduced at 50 sccm.
  • the vacuum atmosphere pressure was 1.1 Pa, the applied power was 1 kw, and the film formation time was 1 hour.
  • FIG. 13 is a micrograph of a cross section in the thickness direction of the negative electrode current collector 53.
  • FIG. 14 is a photomicrograph of the cross section in the thickness direction of the laminate of the negative electrode 52 and the negative electrode current collector 53. From FIG. 14, it is apparent that a thin film that is the negative electrode 52 is formed on the surface (upper surface) of the electrolytic copper foil that is the negative electrode current collector 53 so as to follow the unevenness of the surface of the electrolytic copper foil.
  • the specific surface area of the negative electrode 52 surface was 11.4. Since the surface of the negative electrode 52 reproduces the unevenness of the surface of the negative electrode current collector 53 almost accurately, a value close to the specific surface area of the surface of the negative electrode current collector 53 was obtained.
  • a coin-type electricity storage device was manufactured by placing the two facing each other. This electricity storage device was charged and discharged three times. At this time, the current value was 0.1 mA, the upper limit voltage was 1.5V, and the lower limit voltage was 0V.
  • the SOC of the negative electrode was adjusted to 50%. That is, a lithium metal layer having a thickness of 1.3 ⁇ m was formed on the negative electrode surface by vapor deposition. This was punched and cut into a disk shape having a diameter of 13.5 mm to form a laminate of lithium metal, a negative electrode, and a negative electrode current collector. The lithium metal deposited on the surface of the negative electrode is absorbed by the negative electrode without being immersed in the electrolyte, and the negative electrode is charged (lithium charging). In addition to the irreversible capacity of the negative electrode, this lithium charge amount is an amount corresponding to the charge electricity amount charged to SOC 50%.
  • the negative electrode thickness after the SOC adjustment was 0.6 ⁇ m.
  • the negative electrode laminate (B-2) was produced by the following method.
  • a rolled copper foil (specific surface area 7.0, arithmetic average surface roughness (Ra) 1.24 ⁇ m, thickness 15 ⁇ m) was used for the negative electrode current collector.
  • RF sputtering was performed under the same conditions as described above to form a negative electrode made of a silicon thin film.
  • the negative electrode laminated body which consists of a negative electrode collector and a negative electrode was obtained.
  • the negative electrode was a thin film having a thickness of 0.7 ⁇ m.
  • the specific surface area of the negative electrode surface was 7.1. Since the unevenness of the surface of the negative electrode current collector was almost accurately reproduced on the surface of the negative electrode, a value close to the specific surface area of the surface of the negative electrode current collector was obtained.
  • capacitance of the negative electrode was confirmed by the method similar to the above, the reversible capacity
  • a lithium metal layer having a thickness of 1.6 ⁇ m was formed on the negative electrode surface by vapor deposition. As a result, the SOC of the negative electrode was adjusted to 50%. The negative electrode thickness after the SOC adjustment was 1.4 ⁇ m.
  • the negative electrode laminate (B-3) was produced by the following method.
  • a rolled copper foil (specific surface area 1.0, arithmetic average surface roughness (Ra) 0.12 ⁇ m, thickness 15 ⁇ m) was used for the negative electrode current collector.
  • RF sputtering was performed under the same conditions as described above to form a negative electrode made of a silicon thin film.
  • the negative electrode laminated body which consists of a negative electrode collector and a negative electrode was obtained.
  • the negative electrode was a thin film having a thickness of 0.7 ⁇ m.
  • FIG. 15 is a photomicrograph of a cross section in the thickness direction of the negative electrode current collector 62.
  • FIG. 15 is a photomicrograph of a cross section in the thickness direction of the negative electrode current collector 62.
  • FIG. 16 is a photomicrograph of the cross section in the thickness direction of the laminate of the negative electrode 61 and the negative electrode current collector 62. From FIG. 16, it is clear that a thin film that is the negative electrode 61 is formed on the surface of the rolled copper foil that is the negative electrode current collector 62 so as to follow the irregularities on the surface of the rolled copper foil. Moreover, the specific surface area of the negative electrode 61 surface was 1.1. Since the surface of the negative electrode 61 reproduces the unevenness of the surface of the negative electrode current collector 62 almost accurately, a value close to the specific surface area of the surface of the negative electrode current collector 62 was obtained.
  • capacitance of the negative electrode was confirmed by the method similar to the above, the reversible capacity
  • a lithium metal layer having a thickness of 1.6 ⁇ m was formed on the negative electrode surface by vapor deposition. As a result, the SOC of the negative electrode was adjusted to 50%. The negative electrode thickness after the SOC adjustment was 1.4 ⁇ m.
  • the electricity storage devices (B-1) to (B-3) For the electricity storage devices (B-1) to (B-3), a charge / discharge capacity evaluation was performed.
  • the electricity storage devices (B-1) to (B-3) have a positive electrode capacity of 0.08 mAh, and use a negative electrode having a sufficiently excessive amount of reversible capacity with respect to the positive electrode capacity.
  • the negative electrode capacity is sufficiently higher than the positive electrode capacity. large. Therefore, the theoretical charge / discharge capacity of these electricity storage devices is 0.08 mAh.
  • the charge / discharge capacity was evaluated at a constant current charge / discharge of 0.6 mA, 1.8 mA, or 3 mA, a charge upper limit voltage of 3.75 V, a discharge lower limit voltage of 2.75 V, and a charge pause time and a discharge pause time of 1 minute each. Went as.
  • the charging pause time is the time from the end of charging until the start of the next discharge.
  • the discharge pause time is the time from the end of discharge until the start of the next charge. This charge / discharge was repeated three times, and the third discharge capacity was defined as the charge / discharge capacity. The results are shown in Table 4. Table 4 also shows the specific surface area of the negative electrode in each power storage device.
  • the resistance value of the power storage device (B-3) was 30 ohms larger than the resistance value of the power storage device (B-1). Since the electricity storage device (B-1) has exactly the same configuration as the electricity storage device (B-3) except for the negative electrode, it was confirmed that the impedance of the electricity storage device is reduced by increasing the specific surface area of the negative electrode. .
  • the specific surface area of the negative electrode is preferably 5 or more when a specific non-carbon material which is a negative electrode active material having a very large energy amount per material is used and a thin film negative electrode having a thickness of 10 ⁇ m or less is used.
  • a specific non-carbon material which is a negative electrode active material having a very large energy amount per material
  • a thin film negative electrode having a thickness of 10 ⁇ m or less.
  • Example 7 An electricity storage device (B-4) was produced in the same manner as the electricity storage device (B-1) of Example 6, except that the same positive electrode laminate as in Example 3 using the ⁇ -conjugated polymer as the positive electrode active material was used. Further, an electricity storage device (B-5) was produced in the same manner as the electricity storage device (B-1) of Example 6, except that the same positive electrode laminate as that of Example 4 using the above radical polymer as the positive electrode active material was used.
  • charge / discharge capacity evaluation was performed.
  • the charge / discharge capacity was evaluated with a charge / discharge current value of 4 mA, a charge upper limit voltage of 4.2 V, a discharge lower limit voltage of 2.75 V, and a charge pause time and a discharge pause time of 1 minute each.
  • the charging pause time is the time from the end of charging until the start of the next discharge.
  • This charge / discharge was repeated three times, and the third discharge capacity was defined as the charge / discharge capacity.
  • the obtained charge / discharge capacity was 0.14 mAh in the electricity storage device (B-4) and 0.08 mAh in the electricity storage device (B-5), and a high capacity as designed was obtained.
  • the organic compound capable of oxidation and reduction which is a positive electrode active material, has a higher capacity than activated carbon and enables operation at a higher voltage, so that an electric storage device with higher capacity and practicality can be obtained. It was.
  • Example 8 the SOC of the negative electrode when the power storage device was configured was examined.
  • a negative electrode (thickness 7 ⁇ m, specific surface area 4.0) made of a thin film of silicon oxide (SiOx) was formed on the copper foil by electron beam heating vapor deposition.
  • the negative electrode laminated body which consists of a negative electrode collector and a negative electrode was obtained.
  • the negative electrode thickness was adjusted by adjusting the deposition time.
  • the conditions for electron beam heating vapor deposition are as follows.
  • silicon metal with a purity of 99.9999% manufactured by Kojundo Chemical Laboratory Co., Ltd.
  • oxygen gas with a purity of 99.7% manufactured by Nippon Oxygen Co., Ltd.
  • the degree of vacuum was adjusted to 3 ⁇ 10 ⁇ 3 Pa.
  • the acceleration voltage of the electron beam irradiated to the vapor deposition source was 8 kV, and the emission was 500 mA.
  • a separator (thickness 20 ⁇ m) made of a porous polyethylene sheet is formed by punching and cutting a negative electrode laminate produced by the same method as above into a disc shape having a diameter of 13.5 mm and a counter electrode made of a lithium metal plate (thickness 300 ⁇ m).
  • a coin-type electricity storage device was manufactured by facing each other. This electricity storage device was charged and discharged three times. At this time, the current value was 0.5 mA, the upper limit voltage was 1.5 V, and the lower limit voltage was 0 V.
  • the negative electrode was mechanically charged, and then the SOC of the negative electrode was adjusted by electrochemical charging.
  • the negative electrode SOC was determined by the same method as in Example 1. Specifically, a lithium metal layer having a thickness of 3 ⁇ m corresponding to an irreversible capacity (0.6 mAh) was formed on the negative electrode surface of the negative electrode laminate obtained above by an evaporation method. The lithium metal deposited on the surface of the negative electrode was absorbed by the negative electrode without immersing the negative electrode in the electrolyte, and the irreversible capacity was charged (lithium charge) in the negative electrode.
  • a coin-type electricity storage device is obtained by making a negative electrode laminate after mechanical charging punched and cut into a disk shape having a diameter of 13.5 mm and a counter electrode made of a lithium metal plate (thickness 300 ⁇ m) with a separator interposed therebetween. Produced.
  • the negative electrode SOC is changed to 20%, 40%, 50%, 70%, 80%, 90%, 0%, or 10%, respectively.
  • To (C-8) were obtained. Note that the amount of charge to make the negative electrode SOC 20%, 40%, 50%, 70%, 80%, 90%, 0%, or 10% is 0.42 mAh, 0.84 mAh, and 1.05 mAh, respectively. 1.47 mAh, 1.68 mAh, 1.89 mAh, 0 mAh, or 0.21 mAh.
  • the thicknesses of the negative electrodes (C-1) to (C-8) after the SOC adjustment are 6.8 ⁇ m, 7.6 ⁇ m, 8.1 ⁇ m, 8.7 ⁇ m, 9.2 ⁇ m, 9.6 ⁇ m, and 6. 0 ⁇ m and 6.5 ⁇ m, both of which were 10 ⁇ m or less.
  • the same thing as the electrical storage device of Example 1 was used for the separator and the electrolyte.
  • an electricity storage device (C) was prepared in the same manner as in Example 1 except that a negative electrode laminate including a negative electrode (thickness: 7 ⁇ m) without adjusting SOC (not mechanically and electrochemically charged with respect to the negative electrode) was used. ⁇ 9) was produced. Note that this negative electrode was not subjected to a charge process for an irreversible capacity corresponding to 30% of the reversible capacity, so the SOC of the negative electrode in the configuration of the electricity storage device was set to ⁇ 30% for convenience. Electric storage devices (C-1) to (C-9) were produced in the same manner as in Example 1, except that the negative electrode laminates (C-1) to (C-9) were used.
  • the electricity storage devices (C-1) to (C-9) were evaluated for charge / discharge capacity and impedance.
  • the charge / discharge capacity was evaluated by performing constant current charge / discharge at a current value of 4 mA, a charge upper limit voltage of 3.75 V and a discharge lower limit voltage of 2.75 V, and a charge pause time and a discharge pause time of 1 minute each.
  • the charging pause time is the time from the end of charging until the start of the next discharge. This charge / discharge was repeated three times, and the third discharge capacity was defined as the charge / discharge capacity.
  • impedance evaluation was performed in the discharge state after completion
  • the impedance of the electricity storage device here is an index by which the output characteristics of the electricity storage device can be known. For example, when the impedance of the electricity storage device is small, it means that the electricity storage device has low resistance and high output characteristics, and when the impedance is large, it means that the electricity storage device has high resistance and does not have high output characteristics. .
  • the evaluation results are shown in Table 5. Table 5 also shows the negative electrode SOC (%) at the time of device configuration (during discharge immediately after fabrication) and the negative electrode SOC (%) at the time of device charging.
  • the electricity storage devices (C-1) to (C-8) exhibited a charge / discharge capacity of 0.08 to 0.10 mAh, and their operation as electricity storage devices could be confirmed.
  • the voltage at the time of charging and discharging of this electricity storage device was 2.75 to 3.75 V, which was about 3 V or higher, which was higher than that of the conventional electric double layer capacitor. That is, an electricity storage device having a high capacity capable of operating at a high voltage was obtained.
  • the charge / discharge capacity could not be obtained with the electricity storage device (C-9), which is probably due to the irreversible capacity of the negative electrode. That is, it seems that part of the charged electricity immediately after the production was consumed as the irreversible capacity of the negative electrode and could not be discharged.
  • a favorable charge / discharge capacity was obtained because the irreversible capacity of the negative electrode was charged in advance during the SOC adjustment process of the negative electrode.
  • the utilization factor of the negative electrode active material was 4 to 5%, that is, the difference between the negative electrode SOC during charging and discharging in the electricity storage device was 4 to 5%. Met. From this, when the negative electrode SOC used for the electricity storage device is 0 to 95%, a high capacity electricity storage device that operates at an operating voltage of 2.75 to 3.75 V and approximately 3 V or more can be obtained. all right. From the results in Table 5, it was found that the impedance of the electricity storage device greatly depends on the SOC of the negative electrode.
  • charge / discharge repetition tests were performed using the electricity storage devices (C-1), (C-3), (C-6), and (C-8).
  • the charge / discharge conditions were a charge / discharge current of 4 mA, a charge upper limit voltage of 3.75 V, and a discharge lower limit voltage of 2.75 V.
  • the charge pause time until the start of the next discharge after the end of the charge and the discharge pause time until the start of the next charge after the end of the discharge were each set to 1 minute.
  • Such charging / discharging was repeated 500 times.
  • This charge / discharge test was repeated 6 times, that is, until the total number of cycles was 3000.
  • every time charge / discharge was repeated 500 times charge / discharge was performed three times under the same conditions as described above except that the charge / discharge current value was set to 0.5 mA, and the discharge capacity for the third time was obtained.
  • the capacity maintenance ratio in FIG. 17 represents the ratio of the discharge capacity obtained at each cycle to the initial discharge capacity in percentage. From FIG. 17, it was found that the charge / discharge repetition characteristics of the electricity storage device largely depended on the negative electrode SOC of the electricity storage device. Specifically, in the electricity storage devices (C-1), (C-3), and (C-6) in which the negative electrode SOC during charging / discharging is in the range of 20 to 95%, the number of repetitions is 3000 times. In the electricity storage device (C-8) in which the negative electrode SOC during charging / discharging is 10% while the capacity maintenance rate is 50% or more, the capacity maintenance rate is increased to 20% when the number of repetitions is 3000 times.
  • the SOC of the negative electrode during charge / discharge of the electricity storage device is preferably 20 to 95% because an electricity storage device having a high capacity and excellent output characteristics and charge / discharge repetition characteristics can be obtained. .
  • Example 9 An electricity storage device (C-10) was produced in the same manner as the electricity storage device (C-3) of Example 11, except that the same positive electrode laminate as in Example 3 using the ⁇ -conjugated polymer as the positive electrode active material was used. Further, a power storage device (C-11) was produced in the same manner as the power storage device (C-3) of Example 11 except that the same positive electrode laminate as that of Example 4 using the above radical polymer as the positive electrode active material was used. .
  • the charge / discharge capacity of the electricity storage devices (C-10) and (C-11) was evaluated as follows.
  • the charge / discharge conditions are a charge / discharge current value of 4 mA, a charge upper limit voltage of 4.2 V, and a discharge lower limit voltage of 2.75 V.
  • After the end of charge the charge rest time until the start of the next discharge, and after the end of discharge, The discharge pause time until the start of charging was 1 minute each. This charge / discharge was repeated three times, and the third discharge capacity was defined as the charge / discharge capacity.
  • the evaluation results are shown in Table 6 together with the results of the electricity storage device (C-3).
  • Example 10 the form of the negative electrode current collector was examined.
  • a negative electrode (thickness: 3.0 ⁇ m) made of a thin film of silicon oxide (SiOx) was formed on the layered negative electrode current collector by electron beam heating vapor deposition.
  • the negative electrode thickness was adjusted by adjusting the deposition time.
  • the conditions for electron beam heating vapor deposition are as follows.
  • silicon metal with a purity of 99.9999% manufactured by Kojundo Chemical Laboratory Co., Ltd.
  • oxygen gas with a purity of 99.7% manufactured by Nippon Oxygen Co., Ltd.
  • the acceleration voltage of the electron beam irradiated to the vapor deposition source was 8 kV, and the emission was 500 mA.
  • the capacity of the negative electrode obtained above was confirmed as follows.
  • a negative electrode produced in the same manner as above and a counter electrode made of lithium metal (thickness: 300 ⁇ m) were arranged to face each other through a separator (thickness: 20 ⁇ m) made of a porous polyethylene sheet to produce a coin-type electricity storage device.
  • This electricity storage device was charged and discharged three times.
  • the current value was 0.1 mA
  • the upper limit voltage was 1.5V
  • the lower limit voltage was 0V.
  • the reversible capacity capable of charging / discharging was 0.72 mAh / cm 2
  • the irreversible capacity not contributing to charging / discharging was 0.22 mAh / cm 2 .
  • the negative electrode obtained above is in a completely discharged state, that is, in a state where the SOC is 0% because the negative electrode active material in the negative electrode immediately after production does not contain lithium.
  • the SOC of the negative electrode is an index that represents the state of charge of the single negative electrode, not the entire power storage device, and represents the percentage of the charge amount with respect to the full charge amount as a percentage with the capacity when the negative electrode is fully charged being 100%. Value. Therefore, the fully discharged SOC is 0%, and the fully charged SOC is 100%.
  • SOC of a negative electrode active material is calculated
  • the charge amount of the negative electrode when charged at 0.2 CA (5-hour rate) with respect to the negative electrode capacity is defined as SOC of 100% (full charge).
  • SOC value can be obtained based on the charged amount.
  • a 3.0 ⁇ m-thick lithium metal layer was formed on the negative electrode surface obtained above by an evaporation method, and the SOC of the negative electrode was adjusted to 50%.
  • the lithium metal deposited on the surface of the negative electrode is absorbed by the negative electrode without being immersed in the electrolyte, and the negative electrode is charged (lithium charging).
  • this lithium charge amount is an amount corresponding to the charge electricity amount charged to SOC 50%.
  • the SOC 50% negative electrode thus obtained had a film thickness of 4.5 ⁇ m.
  • An electricity storage device was produced in the same manner as in Example 1 except that the above negative electrode laminate was used.
  • the following negative electrode current collectors (D-1) to (D-7) were used in the preparation of the negative electrode laminate.
  • This negative electrode current collector was produced by pattern plating of a rolled copper foil. Pattern plating is performed by applying a negative photoresist on a rolled copper foil having a thickness of 20 ⁇ m, and using a negative mask arranged so that a 10 ⁇ m square pattern occupies 92% of the copper foil surface. The resist film was exposed and developed, and copper particles were deposited in the formed grooves by an electrolytic method, and then the resist was removed to obtain a copper foil having protrusions having a trapezoidal shape on the surface.
  • FIG. 18 is a scanning electron microscope (SEM) photograph of the main part in the cross section in the thickness direction of the negative electrode current collector 70 which is the negative electrode current collector (D-1).
  • the negative electrode current collector 70 includes a current collector film 71 that is a rolled copper foil, and a plurality of protrusions 72 that are formed on the surface of the current collector film 71.
  • the protrusions 72 were formed on both sides of the current collecting film 71 in the thickness direction.
  • the cross-sectional shape in the thickness direction of the protrusion 72 was a pseudo trapezoid, and the height of the protrusion 72 was 15 ⁇ m.
  • the thickness of the negative electrode current collector 70 including the protrusions 72 is 50 ⁇ m
  • the occupied area of the protrusions 72 on the surface of the current collector film 71 is 8%
  • the volume ratio of the electrolyte holding portion to the occupied volume of the negative electrode current collector 70 is 55%.
  • the occupation area of the protrusions 72 is the ratio of the total area of the portions where the protrusions 72 are formed on the surface of the negative electrode current collector 70 to the area of the surface of the negative electrode current collector 70.
  • the height of the protrusion 72 and the thickness of the negative electrode current collector 70 were measured by observing the current collector with a cross-sectional electron microscope.
  • the area occupied by the protrusion 72 on the surface of the current collector 71 was measured by observation of the current collector with a surface electron microscope. Using these values, the volume ratio of the electrolyte holding portion to the occupied volume of the negative electrode current collector 70 was calculated.
  • the negative electrode current collector (D-2) a copper foil (specific surface area 1.4) having a plurality of protrusions on both surfaces in the thickness direction was used.
  • This negative electrode current collector was produced by pattern plating of a rolled copper foil. Pattern plating is performed by applying a negative photoresist on a rolled copper foil having a thickness of 20 ⁇ m and using a negative mask arranged so that a 10 ⁇ m square pattern occupies 85% of the copper foil surface. The resist film was exposed and developed, and copper particles were deposited in the formed grooves by an electrolytic method, and then the resist was removed to obtain a copper foil having protrusions having a trapezoidal shape on the surface.
  • the cross-sectional shape of the protrusion in the thickness direction was a pseudo trapezoid, and the height of the protrusion was 15 ⁇ m.
  • the thickness of the negative electrode current collector including the protrusions was 50 ⁇ m, the area occupied by the protrusions on the surface of the current collector film was 15%, and the volume ratio of the electrolyte holding part to the volume occupied by the negative electrode current collector was 51%. .
  • the negative electrode current collector (D-3) a copper foil (specific surface area 1.4) having a plurality of protrusions on both surfaces in the thickness direction was used.
  • This negative electrode current collector was produced by pattern plating of a rolled copper foil.
  • a negative photoresist is applied on a rolled copper foil having a thickness of 18 ⁇ m, and a negative mask on which a 10 ⁇ m square pattern occupies 85% of the copper foil surface is used.
  • the resist film was exposed and developed, and copper particles were deposited in the formed grooves by an electrolytic method, and then the resist was removed to obtain a copper foil having protrusions having a trapezoidal shape on the surface.
  • the cross-sectional shape of the protrusion in the thickness direction was a pseudo trapezoid, and the height of the protrusion was 12 ⁇ m.
  • the thickness of the negative electrode current collector including the protrusions was 42 ⁇ m, the area occupied by the protrusions on the surface of the current collector film was 15%, and the volume ratio of the electrolyte holding part to the volume occupied by the negative electrode current collector was 49%. .
  • the negative electrode current collector (D-4) a copper foil (specific surface area 1.4) having a plurality of protrusions on both surfaces in the thickness direction was used.
  • This negative electrode current collector was produced by pattern plating of a rolled copper foil. Pattern plating is performed by applying a negative photoresist on a rolled copper foil having a thickness of 22 ⁇ m, and using a negative mask arranged so that a 10 ⁇ m square pattern occupies 92% of the copper foil surface. The resist film was exposed and developed, and copper particles were deposited in the formed grooves by an electrolytic method, and then the resist was removed to obtain a copper foil having protrusions having a trapezoidal shape on the surface.
  • the cross-sectional shape of the protrusion in the thickness direction was a pseudo trapezoid, and the height of the protrusion was 10 ⁇ m.
  • the thickness of the negative electrode current collector including the protrusions was 42 ⁇ m, the area occupied by the protrusions on the surface of the current collector film was 8%, and the volume ratio of the electrolyte holding portion to the volume occupied by the negative electrode current collector was 44%. .
  • the negative electrode current collector (D-5) includes copper foam metal (thickness 200 ⁇ m, average pore diameter 100 ⁇ m, porosity (volume ratio of electrolyte holding portion to negative electrode current collector occupied volume) 80%, manufactured by Mitsubishi Materials Corporation. ) Was used.
  • FIG. 19 is a scanning electron microscope (SEM) photograph of the main part in the cross section in the thickness direction of the negative electrode current collector 75 which is the negative electrode current collector (D-6).
  • the negative electrode current collector 75 does not have a protrusion on the surface in the thickness direction and does not have a through hole penetrating in the thickness direction. Therefore, the electrolyte holding portion volume with respect to the current collector occupied volume of the negative electrode current collector 75 is 0%.
  • the electrode current collector (D-6) was used, the specific surface area of the negative electrode was 1.1.
  • a copper foil (specific surface area 1.4) having a plurality of protrusions on both surfaces in the thickness direction was used.
  • This negative electrode current collector was produced by pattern plating of a rolled copper foil.
  • a negative photoresist is applied onto a rolled copper foil having a thickness of 26 ⁇ m, and a negative mask on which a 10 ⁇ m square pattern occupies 70% of the surface of the copper foil is used.
  • the resist film was exposed and developed, and copper particles were deposited in the formed grooves by an electrolytic method, and then the resist was removed to obtain a copper foil having protrusions having a trapezoidal shape on the surface.
  • the cross-sectional shape of the protrusion in the thickness direction was a pseudo trapezoid, and the height of the protrusion was 8 ⁇ m.
  • the thickness of the negative electrode current collector including the protrusions was 42 ⁇ m, the area occupied by the protrusions on the surface of the current collector film was 30%, and the volume ratio of the electrolyte holding portion to the volume occupied by the negative electrode current collector was 27%. .
  • power storage devices (D-1) to (D-7) were produced, respectively.
  • the electricity storage devices (D-1) to (D-7) charge / discharge capacity evaluation was performed.
  • the electricity storage devices (D-1) to (D-7) have a positive electrode capacity of 0.08 mAh, and use a negative electrode having a reversible capacity that is sufficiently excessive with respect to the positive electrode capacity. Big enough. Therefore, the theoretical charge / discharge capacity of these electricity storage devices is 0.08 mAh.
  • the charge / discharge capacity was evaluated by constant current charge / discharge of 4 mA, a charge upper limit voltage of 3.75 V and a discharge lower limit voltage of 2.75 V, and a charge pause time and a discharge pause time of 1 minute each.
  • the charging pause time is the time from the end of charging until the start of the next discharge.
  • the discharge pause time is the time from the end of discharge until the start of the next charge. This charge / discharge was repeated three times, and the third discharge capacity was defined as the charge / discharge capacity.
  • Table 7 shows the evaluation results. Table 7 shows the characteristics of the negative electrode current collector in each power storage device, the ratio of the protrusion height or through-hole diameter in the negative electrode current collector to the negative electrode film formation thickness (4.5 ⁇ m) (projection height / negative electrode film formation). (Thickness, through-hole diameter / negative electrode film-forming thickness) are also shown.
  • the volume ratio of the electrolyte holding portion to the occupied volume of the negative electrode current collector is as high as 44 to 55%.
  • the electrolyte could be retained on the current collector surface.
  • the storage devices (D-1) to (D-4) have a high discharge capacity as designed.
  • the electricity storage device (D-5) using the negative electrode current collector (D-5) made of a porous film having through-holes in the thickness direction the electrolyte retention effect by the negative electrode current collector is sufficiently exhibited, and the high capacity was gotten.
  • the negative electrode current collector (D-5) has the highest volume ratio (porosity) of the electrolyte holding part to the occupied volume of the negative electrode current collector among the respective negative electrode current collectors in Table 7, and is the highest. It was found to have the best retention characteristics.
  • the discharge capacity was reduced to 0.05 mAh because the electrolyte retention effect by the negative electrode current collector was almost zero.
  • the discharge capacity of the electricity storage device (D-7) is slightly improved compared to the electricity storage device (D-6), but the discharge capacity is lower than that of the electricity storage devices (D-1) to (D-4). Obtained. From the above, it was found that the volume ratio of the electrolyte holding part is preferably 30% or more in order to improve the charge / discharge characteristics of the electricity storage device.
  • Example 11 A power storage device (D-8) was produced in the same manner as the power storage device (D-1) of Example 10, except that the same positive electrode laminate as that of Example 3 using the ⁇ -conjugated polymer as the positive electrode active material was used. Further, an electricity storage device (D-9) was produced in the same manner as the electricity storage device (D-1) of Example 10 except that the same positive electrode laminate as that of Example 4 using the radical polymer as a positive electrode active material was used. .
  • the electricity storage devices (D-8) and (D-9) were evaluated for charge / discharge capacity.
  • the charge / discharge capacity was evaluated with a charge / discharge current value of 4 mA, a charge upper limit voltage of 4.2 V, and a discharge lower limit voltage of 2.75 V, and a charge pause time and a discharge pause time of 1 minute each.
  • the charging pause time is the time from the end of charging until the start of the next discharge.
  • This charge / discharge was repeated three times, and the third discharge capacity was defined as the charge / discharge capacity.
  • the obtained charge / discharge capacity was 0.14 mAh for the electricity storage device (D-8) and 0.08 mAh for the electricity storage device (D-9), and a high capacity as designed could be obtained.
  • the volume ratio of the electrolyte holding part to the volume occupied by the negative electrode current collector was as high as 55%, and the electrolyte could be held in the negative electrode current collector.
  • the electricity storage device of the present invention Since the electricity storage device of the present invention has high output, high capacity, and excellent charge / discharge repetition characteristics, it can be suitably used as a power source for transportation equipment, electrical / electronic equipment, and an uninterruptible power source.
  • Examples of the transportation device include a hybrid vehicle.
  • Examples of electric / electronic devices include mobile communication devices and portable devices.

Abstract

This invention provides an electrical storage device comprising a positive electrode current collector, a positive electrode provided on the positive electrode current collector and containing a positive electrode active material, which can reversibly adsorb and desorb at least an anion, a negative electrode current collector, and a negative electrode provided on the negative electrode current collector and formed of a negative electrode active material which can substantially reversibly occlude and release lithium ions. The negative electrode active material is at least one material selected from the group consisting of silicon, a silicon-containing alloy, a silicon compound, tin, a tin-containing alloy, and a tin compound, and the negative electrode is a thin film having a thickness of not more than 10 μm.

Description

蓄電デバイスElectricity storage device
　本発明は、高出力および高容量を有し、繰り返し充放電寿命特性に優れた蓄電デバイスに関する。 The present invention relates to an electricity storage device having a high output and a high capacity and having excellent repeated charge / discharge life characteristics.
　従来から、充放電可能な蓄電デバイスは、ガソリンと電気という２つのエネルギーを用いて駆動するハイブリッド自動車、各種電子機器、特に移動体通信機器、携帯電子機器などの電源、無停電電源などに用いられている。最近におけるハイブリッド自動車や電子機器の普及に伴い、蓄電デバイスに対する高性能化への要求が非常に高まっている。このような要求に対して、蓄電デバイスの１種である電気二重層キャパシタに関する研究開発が盛んに行われている。電気二重層キャパシタは、高出力でかつ繰り返し充放電寿命特性に優れるという特徴を有し、主に高出力用途への応用が期待されるが、二次電池に比べて、容量すなわちエネルギー密度が低い。 Conventionally, chargeable / dischargeable power storage devices are used for power sources such as hybrid vehicles driven by using two types of energy, gasoline and electricity, various electronic devices, especially mobile communication devices, portable electronic devices, and uninterruptible power supplies. ing. With the recent spread of hybrid vehicles and electronic devices, the demand for higher performance of power storage devices is increasing. In response to such demands, research and development related to electric double layer capacitors, which are one type of power storage device, have been actively conducted. Electric double layer capacitors have the characteristics of high output and excellent repeated charge / discharge life characteristics, and are expected to be applied mainly to high output applications, but have a lower capacity or energy density than secondary batteries. .
　電気二重層キャパシタの高容量化には、たとえば、電気二重層キャパシタの正極活物質とリチウムイオン電池の負極活物質とを選定し、正極活物質および負極活物質自体の最適化、組み合わせの最適化などについて、種々検討されている。負極活物質としては、たとえば、グラファイト、ポリアセンなどの結晶質または非晶質の炭素材料が検討されている。これらの炭素材料は、充放電によりリチウムイオンを可逆的に吸蔵・放出し得る材料である。これらの炭素材料の製造法、活性炭などの電気二重層キャパシタの正極活物質とこれらの炭素材料を含む負極とを組み合わせた蓄電デバイスなどが数多く提案されている（たとえば、特許文献１および特許文献２参照）。 To increase the capacity of the electric double layer capacitor, for example, select the positive electrode active material of the electric double layer capacitor and the negative electrode active material of the lithium ion battery, optimize the positive electrode active material and the negative electrode active material itself, and optimize the combination Various studies have been made. As the negative electrode active material, for example, crystalline or amorphous carbon materials such as graphite and polyacene have been studied. These carbon materials are materials capable of reversibly occluding and releasing lithium ions by charging and discharging. There have been proposed a number of methods for producing these carbon materials, power storage devices in which a positive electrode active material of an electric double layer capacitor such as activated carbon and a negative electrode containing these carbon materials are combined (for example, Patent Document 1 and Patent Document 2). reference).
　また、炭素材料よりも容量密度の大きい負極活物質を用いることによって、蓄電デバイスを高容量化しようとする試みがなされている。このような負極活物質としては、炭素材料を改質してなる負極活物質、炭素材料以外の負極活物質などが挙げられる。炭素材料を改質してなる負極活物質としては、「黒鉛を除く光学的異方性炭素質物を賦活処理した負極活物質、それらの表面の一部又は全部が炭素材料及び／又は珪素材料によって被覆された負極活物質」が提案される（たとえば、特許文献２参照）。炭素材料以外の負極活物質として、錫酸化物、珪素酸化物などの金属酸化物（たとえば、特許文献３および４参照）が提案される。 In addition, attempts have been made to increase the capacity of the electricity storage device by using a negative electrode active material having a larger capacity density than the carbon material. Examples of such a negative electrode active material include a negative electrode active material obtained by modifying a carbon material, a negative electrode active material other than a carbon material, and the like. As the negative electrode active material obtained by modifying the carbon material, “a negative electrode active material obtained by activating an optically anisotropic carbonaceous material excluding graphite, and a part or all of the surface thereof is made of a carbon material and / or a silicon material. A coated negative electrode active material ”is proposed (see, for example, Patent Document 2). As negative electrode active materials other than carbon materials, metal oxides such as tin oxide and silicon oxide (for example, see Patent Documents 3 and 4) are proposed.
　特許文献２～４には、それぞれの特許文献に開示の負極活物質と、活性炭である正極活物質との組み合わせが開示されている。特に、特許文献３および４には、珪素酸化物、錫酸化物などの非炭素材料である負極活物質と、活性炭である正極活物質との組み合わせにより、過放電特性に優れた蓄電デバイスが得られるとの開示がある。より具体的には、特許文献３の実施例１では、粒径４４μｍ以下に粉砕、整粒した一酸化ケイ素粒子（負極活物質）と、グラファイト（導電剤）と、ポリアクリル酸（結着剤）とをそれぞれ重量比４５：４０：１５の割合で混合して負極合剤が調製される。この負極合剤を加圧成形することにより、直径４ｍｍ、厚み０．１９ｍｍのペレット状負極が作製される。このペレット状負極は、負極集電体としての機能をも有する導電性樹脂接着剤によって負極ケースに固定される。このペレット状負極を含む蓄電デバイスは、２Ｖ～放電終止電圧０Ｖまでの過放電領域を含んだ電圧域で動作可能であるが、充放電速度が２００時間率（０．００５Ｃレート）と非常に遅く、出力特性が低い。 Patent Documents 2 to 4 disclose a combination of a negative electrode active material disclosed in each of the patent documents and a positive electrode active material that is activated carbon. In particular, Patent Documents 3 and 4 provide an electricity storage device having excellent overdischarge characteristics by combining a negative electrode active material that is a non-carbon material such as silicon oxide or tin oxide with a positive electrode active material that is activated carbon. There is disclosure to be done. More specifically, in Example 1 of Patent Document 3, silicon monoxide particles (negative electrode active material) pulverized and sized to a particle size of 44 μm or less, graphite (conductive agent), and polyacrylic acid (binder) ) In a weight ratio of 45:40:15, respectively, to prepare a negative electrode mixture. By pelletizing this negative electrode mixture, a pellet-shaped negative electrode having a diameter of 4 mm and a thickness of 0.19 mm is produced. The pellet-like negative electrode is fixed to the negative electrode case with a conductive resin adhesive that also functions as a negative electrode current collector. The electricity storage device including the pellet-shaped negative electrode can operate in a voltage range including an overdischarge region from 2 V to a discharge end voltage of 0 V, but the charge / discharge rate is very slow at a 200 hour rate (0.005 C rate). The output characteristics are low.
　ところで、携帯電子機器などの電子機器に多く用いられるリチウム二次電池は、一般に、１０～０．５時間率（０．１Ｃレート～２Ｃレート）程度の充放電速度を有する。したがって、特許文献３および４の蓄電デバイスはリチウム二次電池の代替用途には使用できないことが明らかである。また、瞬間的に大電流を充放電することが可能である電気二重層キャパシタは、一般に、０．００２～０．０２時間率（５００Ｃレート～５０Ｃレート）程度の充放電速度を有する。したがって、特許文献３および４の蓄電デバイスは、電気二重層キャパシタの代替用途にも使用できない。このように、特許文献３および４において開示された蓄電デバイスは、高電圧および高容量ではあるものの、充放電速度が遅く、出力特性が低いため、用途が限られる。 By the way, lithium secondary batteries often used in electronic devices such as portable electronic devices generally have a charge / discharge rate of about 10 to 0.5 hour rate (0.1 C rate to 2 C rate). Therefore, it is clear that the electricity storage devices of Patent Documents 3 and 4 cannot be used for alternative uses for lithium secondary batteries. An electric double layer capacitor capable of instantaneously charging and discharging a large current generally has a charge / discharge rate of about 0.002 to 0.02 hour rate (500 C rate to 50 C rate). Therefore, the electrical storage device of patent documents 3 and 4 cannot be used also for the alternative use of an electric double layer capacitor. As described above, the power storage devices disclosed in Patent Documents 3 and 4 have a high voltage and a high capacity, but their use is limited because the charge / discharge speed is slow and the output characteristics are low.
　一方、正極活物質としては、現在汎用される活性炭よりも高容量を有する酸化還元可能な有機化合物が検討されている。酸化還元可能な有機化合物としては、π電子共役雲を有する有機化合物（たとえば、特許文献５および６参照）、ラジカルを有する有機化合物（たとえば、特許文献７参照）などが提案されている。しかしながら、これらの特許文献には、酸化還元可能な有機化合物である正極活物質と、非炭素材料である負極活物質との組み合わせについては、報告されていない。 On the other hand, as the positive electrode active material, an organic compound capable of oxidation and reduction having a capacity higher than that of currently used activated carbon is being studied. As organic compounds that can be oxidized and reduced, organic compounds having a π-electron conjugated cloud (for example, see Patent Documents 5 and 6), organic compounds having a radical (for example, see Patent Document 7), and the like have been proposed. However, these patent documents do not report a combination of a positive electrode active material that is an organic compound capable of redox and a negative electrode active material that is a non-carbon material.
国際公開第２００３／００３３９５号パンフレットInternational Publication No. 2003/003395 Pamphlet 特開２００５－０９３７７７号公報JP 2005-093777 A 特開２０００－１９５５５５号公報JP 2000-195555 A 特開２００１－１４８２４２号公報JP 2001-148242 A 特開２００４－１１１３７４号公報JP 2004-111374 A 特開２００４－３４２６０５号公報JP 2004-342605 A 特開２００４－１９３００４号公報JP 2004-193004 A
　そこで、本発明は、負極活物質として非炭素材料を用いるにもかかわらず、高速での充放電が可能であり、高出力、高容量、および優れた繰り返し充放電寿命特性を有する蓄電デバイスを提供することを目的とする。 Therefore, the present invention provides a power storage device that can be charged / discharged at high speed despite having a non-carbon material as a negative electrode active material, and has high output, high capacity, and excellent repeated charge / discharge life characteristics. The purpose is to do.
　本発明者らは、上記課題を解決するために鋭意研究を重ねた。その結果、電気二重層キャパシタ用の正極活物質と、リチウムイオンを可逆的に吸蔵および放出可能な非炭素材料である負極活物質との組み合わせにおいて、負極を特定の構成とすることによって、充放電速度の高速化ひいては高出力化を達成できることを見出した。すなわち、バインダーを用いることなく、負極集電体上に非炭素材料からなる負極を直接形成することによって、充放電速度が速く、高出力および高容量で、繰り返し充放電寿命特性に優れた蓄電デバイスが得られることを見出し、本発明を完成した。 The inventors of the present invention have made extensive studies to solve the above problems. As a result, in a combination of a positive electrode active material for an electric double layer capacitor and a negative electrode active material that is a non-carbon material capable of reversibly occluding and releasing lithium ions, the negative electrode has a specific configuration, thereby charging and discharging It has been found that higher speed and, in turn, higher output can be achieved. In other words, by directly forming a negative electrode made of a non-carbon material on a negative electrode current collector without using a binder, the electricity storage device has a high charge / discharge rate, high output and high capacity, and excellent repeated charge / discharge life characteristics. Was found and the present invention was completed.
　すなわち本発明の蓄電デバイスは、正極集電体と、前記正極集電体上に配された、少なくともアニオンを可逆的に吸脱着可能な正極活物質を含む正極と、負極集電体と、前記負極集電体上に配された、実質的に、リチウムイオンを可逆的に吸蔵および放出可能な負極活物質からなる負極と、を備え、前記負極活物質は、珪素、珪素含有合金、珪素化合物、錫、錫含有合金および錫化合物からなる群より選ばれる少なくとも１つであり、前記負極は厚み１０μｍ以下の薄膜であることを特徴とする。 That is, an electricity storage device of the present invention includes a positive electrode current collector, a positive electrode including at least a positive electrode active material capable of reversibly adsorbing and desorbing anions disposed on the positive electrode current collector, the negative electrode current collector, A negative electrode made of a negative electrode active material that is substantially reversibly occluded and desorbed and is disposed on the negative electrode current collector, wherein the negative electrode active material comprises silicon, a silicon-containing alloy, and a silicon compound. And at least one selected from the group consisting of tin, tin-containing alloys and tin compounds, wherein the negative electrode is a thin film having a thickness of 10 μm or less.
　前記負極の単位面積あたりの容量は、０．２～２．０ｍＡｈ/ｃｍ２であるのが好ましい。
　前記正極の厚みが、前記負極の厚みの５倍以上であるのが好ましい。
　前記負極の比表面積が、５以上であるのが好ましい。
　前記負極集電体の比表面積が５以上であるのが好ましい。 The capacity per unit area of the negative electrode is preferably 0.2 to 2.0 mAh / cm 2 .
The thickness of the positive electrode is preferably 5 times or more the thickness of the negative electrode.
The specific surface area of the negative electrode is preferably 5 or more.
The negative electrode current collector preferably has a specific surface area of 5 or more.
　前記負極集電体の表面粗さＲａの値が、前記負極の厚みと同じかまたはそれよりも大きい値であるのが好ましい。
　前記負極活物質に予めリチウムが吸蔵されているのが好ましい。
　前記負極活物質へのリチウムの吸蔵が機械的に行われるのが好ましい。
　前記蓄電デバイスの充放電時において、前記負極のＳＯＣが２０％以上９５％以下であるのが好ましい。 It is preferable that the surface roughness Ra of the negative electrode current collector is equal to or greater than the thickness of the negative electrode.
It is preferable that lithium is occluded in advance in the negative electrode active material.
It is preferable that lithium is occluded mechanically in the negative electrode active material.
At the time of charge / discharge of the electricity storage device, the SOC of the negative electrode is preferably 20% or more and 95% or less.
　前記負極活物質が、珪素であるのが好ましい。
　前記負極活物質が、珪素窒化物または珪素酸窒化物であるのが好ましい。
　前記珪素化合物が、式ＳｉＯｘ（０＜ｘ＜２）で表される珪素酸化物であるのが好ましい。
　前記正極活物質が活性炭であるのが好ましい。
　前記正極活物質が酸化還元可能な有機化合物であるのが好ましい。
　前記有機化合物は分子内にラジカルを有するのが好ましい。
　前記有機化合物は分子内にπ共役電子雲を有するのが好ましい。 The negative electrode active material is preferably silicon.
The negative electrode active material is preferably silicon nitride or silicon oxynitride.
The silicon compound is preferably a silicon oxide represented by the formula SiOx (0 <x <2).
The positive electrode active material is preferably activated carbon.
The positive electrode active material is preferably an organic compound that can be oxidized and reduced.
The organic compound preferably has a radical in the molecule.
The organic compound preferably has a π-conjugated electron cloud in the molecule.
　前記負極集電体は電解質保持部を有し、前記電解質保持部の容積が前記負極集電体の占有体積の３０％以上であるのが好ましい。
　前記負極集電体は電解質保持部を有し、前記電解質保持部の容積が前記負極集電体の占有体積の５０％以上であるのが好ましい。
　前記負極集電体が、厚み方向に貫通する複数の貫通孔を有する多孔質膜であるのが好ましい。
　前記負極集電体が、厚み方向に貫通する貫通孔を有さずかつ表面に複数の突起を有し、前記突起の前記負極集電体の厚み方向の断面形状が台形状または擬台形状であるのが好ましい。
　前記突起の高さが、前記負極の厚みの２倍以上であるのが好ましい。
　前記突起の先端部の少なくとも一部に、負極活物質を含む被覆層が形成されるのが好ましい。 Preferably, the negative electrode current collector has an electrolyte holding part, and the volume of the electrolyte holding part is 30% or more of the occupied volume of the negative electrode current collector.
Preferably, the negative electrode current collector has an electrolyte holding part, and the volume of the electrolyte holding part is 50% or more of the occupied volume of the negative electrode current collector.
The negative electrode current collector is preferably a porous film having a plurality of through holes penetrating in the thickness direction.
The negative electrode current collector does not have a through-hole penetrating in the thickness direction and has a plurality of protrusions on the surface, and the cross-sectional shape of the protrusion in the thickness direction of the negative electrode current collector is trapezoidal or pseudo-trapezoidal. Preferably there is.
It is preferable that the height of the protrusion is at least twice the thickness of the negative electrode.
It is preferable that a coating layer containing a negative electrode active material is formed on at least a part of the tip of the protrusion.
　本発明によれば、高速で充放電することが可能であり、高出力、高容量、および優れた繰り返し充放電寿命特性を有する蓄電デバイスを提供することができる。高出力時でも容量の低下が起こらず、長時間にわたって高出力を安定的に維持できる蓄電デバイスを提供することができる。 According to the present invention, it is possible to provide an electricity storage device that can be charged / discharged at high speed and has high output, high capacity, and excellent repeated charge / discharge life characteristics. It is possible to provide an electric storage device that does not cause a decrease in capacity even at high output and can stably maintain high output for a long time.
本発明の実施の形態である蓄電デバイス１の構成を模式的に示す縦断面図である。1 is a longitudinal sectional view schematically showing a configuration of an electricity storage device 1 according to an embodiment of the present invention. 負極集電体１３の表面に形成された負極１２の構成を模式的に示す縦断面図である。2 is a longitudinal sectional view schematically showing the configuration of a negative electrode 12 formed on the surface of a negative electrode current collector 13. FIG. 負極集電体１３の表面に形成された別形態の負極１２ａの構成を模式的に示す縦断面図である。4 is a longitudinal sectional view schematically showing a configuration of another form of negative electrode 12a formed on the surface of the negative electrode current collector 13. FIG. 負極集電体１３の構成を模式的に示す縦断面図である。3 is a longitudinal sectional view schematically showing a configuration of a negative electrode current collector 13. FIG. 負極１２と負極集電体１３とからなる負極積層体の構成を模式的に示す縦断面図である。2 is a longitudinal sectional view schematically showing a configuration of a negative electrode laminate including a negative electrode 12 and a negative electrode current collector 13. FIG. 別形態の負極集電体３０の構成を模式的に示す縦断面図である。It is a longitudinal cross-sectional view which shows the structure of the negative electrode collector 30 of another form typically. 負極３３と図６に示す負極集電体３０とからなる負極積層体の構成を模式的に示す縦断面図であるIt is a longitudinal cross-sectional view which shows typically the structure of the negative electrode laminated body which consists of the negative electrode 33 and the negative electrode collector 30 shown in FIG. 突起３６の厚み方向断面形状が三角形である負極集電体３５の構成を模式的に示す縦断面図である。FIG. 4 is a longitudinal sectional view schematically showing a configuration of a negative electrode current collector 35 in which a protrusion 36 has a triangular cross-sectional shape in the thickness direction. 突起高さが不足する突起４４を有する負極積層体４０の構成を模式的に示す縦断面図である。It is a longitudinal cross-sectional view which shows typically the structure of the negative electrode laminated body 40 which has the processus | protrusion 44 with insufficient processus | protrusion height. 本発明の蓄電デバイスを用いた携帯電話の概略斜視図である。It is a schematic perspective view of a mobile phone using the electricity storage device of the present invention. 本発明の蓄電デバイスを用いたノートＰＣの概略斜視図である。It is a schematic perspective view of the notebook PC using the electrical storage device of this invention. 本発明の蓄電デバイスを用いたハイブリッド自動車の概略構成図である。It is a schematic block diagram of the hybrid vehicle using the electrical storage device of this invention. 本発明の実施例６における蓄電デバイス（Ｂ－１）に用いた負極集電体５３の厚み方向断面の顕微鏡写真である。It is a microscope picture of the cross section of the thickness direction of the negative electrode collector 53 used for the electrical storage device (B-1) in Example 6 of this invention. 本発明の実施例６における蓄電デバイス（Ｂ－１）に用いた負極５２と負極集電体５３とからなる負極積層体の厚み方向断面の顕微鏡写真である。It is a microscope picture of the thickness direction cross section of the negative electrode laminated body which consists of the negative electrode 52 and the negative electrode collector 53 which were used for the electrical storage device (B-1) in Example 6 of this invention. 本発明の実施例６における蓄電デバイス（Ｂ－３）に用いた負極集電体６２の厚み方向断面の顕微鏡写真である。It is a microscope picture of the cross section of the thickness direction of the negative electrode collector 62 used for the electrical storage device (B-3) in Example 6 of this invention. 本発明の実施例６における蓄電デバイス（Ｂ－３）に用いた負極６１と負極集電体６２とからなる負極積層体の厚み方向断面の顕微鏡写真である。It is a microscope picture of the thickness direction cross section of the negative electrode laminated body which consists of the negative electrode 61 and the negative electrode collector 62 which were used for the electrical storage device (B-3) in Example 6 of this invention. 本発明の実施例８における、蓄電デバイス（Ｃ－１）、（Ｃ－３）、（Ｃ－６）および（Ｃ－８）の充放電繰り返し試験の結果を示す図である。It is a figure which shows the result of the charging / discharging repetition test of electrical storage device (C-1), (C-3), (C-6), and (C-8) in Example 8 of this invention. 本発明の実施例１０における蓄電デバイス（Ｄ－１）に用いた負極集電体７０の厚み方向断面における要部の電子顕微鏡写真である。It is an electron micrograph of the principal part in the cross section of the thickness direction of the negative electrode collector 70 used for the electrical storage device (D-1) in Example 10 of this invention. 本発明の実施例１０における蓄電デバイス（Ｄ－６）に用いた負極集電体７５の厚み方向断面における要部の電子顕微鏡写真である。It is an electron micrograph of the principal part in the cross section of the thickness direction of the negative electrode collector 75 used for the electrical storage device (D-6) in Example 10 of this invention.
　本発明の蓄電デバイスは、正極、正極集電体、負極および負極集電体を含み、つぎの（イ）および（ロ）の特徴を有する。それ以外の構成は、従来の蓄電デバイスと同様である。
（イ）本発明の最大の特徴は、負極がバインダー、特に有機バインダーを含有せず、かつリチウムイオンを可逆的に吸蔵・放出可能な非炭素材料を負極活物質として含有すること、すなわち実質的に負極活物質の層からなる点である。リチウムイオンを可逆的に吸蔵・放出可能な非炭素材料としては、珪素、珪素含有合金、珪素化合物、錫、錫含有合金および錫化合物から選ばれる少なくとも１種が用いられる。
　粒子形状の非炭素材料を負極活物質として用いる従来の蓄電デバイスでは、非炭素材料の粒子および導電剤をバインダーで結合することによって負極を構成している。本発明者らの研究によれば、前記のような負極では、活物質粒子間の接触抵抗、活物質粒子と集電体表面との接触抵抗、負極が導電剤を含有する場合の活物質粒子と導電剤との接触抵抗などが発生し、蓄電デバイスの内部抵抗を増大させていることが判明した。このため、充放電速度ひいては出力の低下が顕著になるものと推測される。 The electricity storage device of the present invention includes a positive electrode, a positive electrode current collector, a negative electrode, and a negative electrode current collector, and has the following characteristics (a) and (b). Other configurations are the same as those of the conventional power storage device.
(A) The greatest feature of the present invention is that the negative electrode does not contain a binder, particularly an organic binder, and contains a non-carbon material capable of reversibly occluding and releasing lithium ions as a negative electrode active material. And the negative electrode active material layer. As the non-carbon material capable of reversibly occluding and releasing lithium ions, at least one selected from silicon, silicon-containing alloys, silicon compounds, tin, tin-containing alloys and tin compounds is used.
In a conventional power storage device using a non-carbon material in a particle shape as a negative electrode active material, a negative electrode is formed by binding particles of a non-carbon material and a conductive agent with a binder. According to the studies by the present inventors, in the negative electrode as described above, the contact resistance between the active material particles, the contact resistance between the active material particles and the current collector surface, and the active material particles when the negative electrode contains a conductive agent It has been found that contact resistance between the metal and the conductive agent is generated, increasing the internal resistance of the electricity storage device. For this reason, it is presumed that the charge / discharge rate and, consequently, the output is significantly reduced.
　また、本発明のように負極がバインダー、特に有機バインダーを含有しないことによって、初めて蒸着などの薄膜形成プロセスによる機械的充電方法により、負極活物質に予めリチウムを吸蔵させることが可能になる。本発明により、このように負極活物質へのリチウムの機械的な吸蔵が可能になることにより、蓄電デバイスの加工性が顕著に向上する。 In addition, since the negative electrode does not contain a binder, particularly an organic binder, as in the present invention, lithium can be preliminarily occluded in the negative electrode active material by a mechanical charging method using a thin film formation process such as vapor deposition for the first time. The present invention makes it possible to occlude lithium in the negative electrode active material in this way, thereby significantly improving the workability of the electricity storage device.
　本発明の蓄電デバイスにおいて、負極は実質的に非炭素材料からなる。なお、本発明は、負極が非炭素材料とともに無機化合物を含有する形態をも包含している。無機化合物は、負極の機械的強度などを向上させることなどを目的として用いられる。非炭素材料と併用される無機化合物は、電池反応に寄与せずかつ負極にＬｉを吸蔵しても劣化などを起こさない程度の耐熱性を有する無機化合物であり、たとえば、鉄、コバルト、アンチモン、ビスマス、鉛、ニッケル、銅、銀、亜鉛、タリウム、カドミウム、ガリウム、ゲルマニウム、インジウム、チタン、あるいはこれらの化合物、もしくはこれらと珪素の合金、もしくはこれらと錫の合金等などが挙げられる。本発明の負極は、バインダーを含有しないことによって、負極活物質である非炭素材料が連続的に繋がった構造体として形成される。このような構造を採ることによって、負極と負極集電体との電気的な接触抵抗（以下、単に「接触抵抗」とする）を大幅に小さくできる。 In the electricity storage device of the present invention, the negative electrode is substantially made of a non-carbon material. In addition, this invention also includes the form in which a negative electrode contains an inorganic compound with a non-carbon material. The inorganic compound is used for the purpose of improving the mechanical strength of the negative electrode. The inorganic compound used in combination with the non-carbon material is an inorganic compound that does not contribute to the battery reaction and does not deteriorate even if Li is occluded in the negative electrode. For example, iron, cobalt, antimony, Examples thereof include bismuth, lead, nickel, copper, silver, zinc, thallium, cadmium, gallium, germanium, indium, titanium, a compound thereof, an alloy of these with silicon, or an alloy of these with tin. By not containing a binder, the negative electrode of the present invention is formed as a structure in which non-carbon materials that are negative electrode active materials are continuously connected. By adopting such a structure, the electrical contact resistance (hereinafter simply referred to as “contact resistance”) between the negative electrode and the negative electrode current collector can be significantly reduced.
（ロ）負極集電体の表面に、厚み１０μｍ以下の薄膜からなる負極が直接形成される。
　粒子形状の非炭素材料を負極活物質として用いる従来技術では、負極は負極集電体に直接形成されるのではなく、別途作製した負極を負極集電体に接着または接合させている。負極は、たとえば、非炭素材料の粒子と導電剤とバインダーとを混合し、得られる混合物をペレット状に加圧成形することにより作製される。たとえば、特許文献３および４のように粒径４４μｍ以下の非炭素材料粒子を用いると、厚み３０μｍ程度の、表面が平滑な負極を作製できないのは明らかである。従来の方法で作製できるペレット状負極の厚みは、非炭素材料粒子をさらに微細化しても数十μｍ程度が限界であり、たとえば１０μｍ以下のような大幅な薄膜化は困難である。 (B) A negative electrode composed of a thin film having a thickness of 10 μm or less is directly formed on the surface of the negative electrode current collector.
In the prior art using a particulate non-carbon material as the negative electrode active material, the negative electrode is not directly formed on the negative electrode current collector, but a separately prepared negative electrode is bonded or bonded to the negative electrode current collector. The negative electrode is produced, for example, by mixing particles of a non-carbon material, a conductive agent, and a binder, and pressing the resulting mixture into a pellet. For example, when non-carbon material particles having a particle size of 44 μm or less as in Patent Documents 3 and 4 are used, it is apparent that a negative electrode having a thickness of about 30 μm and a smooth surface cannot be produced. The thickness of the pellet-shaped negative electrode that can be produced by a conventional method is limited to about several tens of μm even if the non-carbon material particles are further miniaturized, and it is difficult to make a large thin film such as 10 μm or less.
　これに対し、本発明では、厚み１０μｍ以下の薄膜からなる負極を負極集電体表面に直接形成することによって、従来に比べて負極厚みを大幅に薄くすることができる。負極は、充放電に伴う電子またはイオンの通り道になる。したがって、負極厚みが薄いと、それだけ電子またはイオンの移動距離が短くなり、抵抗が小さくなって、蓄電デバイスの内部抵抗を低減化できる。また、負極集電体表面に負極を直接形成する場合には、たとえば、蒸着などによって負極を形成できるので、蓄電デバイスの加工性が顕著に向上する。 On the other hand, in the present invention, the negative electrode thickness can be significantly reduced as compared with the prior art by directly forming a negative electrode comprising a thin film having a thickness of 10 μm or less on the surface of the negative electrode current collector. The negative electrode becomes a path for electrons or ions accompanying charging and discharging. Therefore, if the thickness of the negative electrode is small, the movement distance of electrons or ions is shortened, the resistance is reduced, and the internal resistance of the electricity storage device can be reduced. In addition, when the negative electrode is directly formed on the surface of the negative electrode current collector, for example, the negative electrode can be formed by vapor deposition or the like, so that the workability of the electricity storage device is significantly improved.
　このように、本発明の蓄電デバイスは、上記（イ）および（ロ）の特徴を持つことによって、従来の蓄電デバイスよりも内部抵抗が著しく小さくなり、高速での充放電および高出力化が可能になる。さらに、本発明の蓄電デバイスは、負極活物質として非炭素材料を用いることによって、高容量で、繰り返し充放電寿命特性にも優れ、かつ、加工性が顕著に向上した蓄電デバイスを提供することができる。この薄膜負極を用いることにより蓄電デバイスの小型化が可能となる。
　なお、ここでいう負極の厚みとは、蓄電デバイス構成時（放電時）における負極の厚みをいう。充放電時において負極活物質はリチウムを可逆的に吸蔵・放出するため、負極の厚みが変化する。 As described above, the power storage device of the present invention has the features (a) and (b) above, so that the internal resistance is remarkably smaller than that of the conventional power storage device, and charging / discharging at high speed and high output are possible. become. Furthermore, the electricity storage device of the present invention can provide an electricity storage device having a high capacity, excellent repeated charge / discharge life characteristics, and remarkably improved workability by using a non-carbon material as a negative electrode active material. it can. By using this thin film negative electrode, it is possible to reduce the size of the electricity storage device.
Here, the thickness of the negative electrode refers to the thickness of the negative electrode when the power storage device is configured (during discharge). Since the negative electrode active material reversibly absorbs and releases lithium during charging and discharging, the thickness of the negative electrode changes.
　単位面積あたりの負極容量としては、０．２～２．０ｍＡｈ／ｃｍ２の容量を示す負極を利用することができる。好ましくは、単位面積あたりの負極容量は０．２～１．０ｍＡｈ／ｃｍ２である。なお、ここでいう、負極容量とは、負極単体として、可逆的な充放電が可能な容量のことを指し、後述する不可逆容量を含まない。具体的には、リチウム基準で０～１．５Ｖの電位範囲において、負極容量に対して０．２ＣＡ（５時間率）で充放電させた場合の可逆容量である。 As the negative electrode capacity per unit area, a negative electrode having a capacity of 0.2 to 2.0 mAh / cm 2 can be used. Preferably, the negative electrode capacity per unit area is 0.2 to 1.0 mAh / cm 2 . Here, the negative electrode capacity refers to a capacity capable of reversible charge / discharge as a single negative electrode, and does not include an irreversible capacity described later. Specifically, it is a reversible capacity when charging / discharging at 0.2 CA (5-hour rate) with respect to the negative electrode capacity in a potential range of 0 to 1.5 V with respect to lithium.
　以下、本発明の蓄電デバイスの一実施の形態を図を参照しながら説明する。
　図１は、本発明の実施の形態であるコイン型蓄電デバイス１の構成を模式的に示す縦断面図である。図２は、負極集電体１３表面に形成された負極１２の構成を模式的に示す縦断面図である。蓄電デバイス１は、正極１０、正極集電体１１、負極１２、負極集電体１３、セパレータ１４、封口板１５、ガスケット１６、スペーサー１７およびケース１８を含む。蓄電デバイス１は、スペーサー１７、負極集電体１３、負極１２、セパレータ１４、正極１０および正極集電体１１の積層体が、封口板１５とケース１８とによって形成される内部空間に収容されてなるコイン型蓄電デバイスである。したがって、図１は蓄電デバイス１の直径方向の断面図と言うこともできる。なお、蓄電デバイス１における、正極集電体１１、正極１０、セパレータ１４、負極１２および負極集電体１３の積層部分には、ほぼ均等な圧力が付加されている。 Hereinafter, an embodiment of an electricity storage device of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view schematically showing a configuration of a coin-type electricity storage device 1 according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view schematically showing the configuration of the negative electrode 12 formed on the surface of the negative electrode current collector 13. The electricity storage device 1 includes a positive electrode 10, a positive electrode current collector 11, a negative electrode 12, a negative electrode current collector 13, a separator 14, a sealing plate 15, a gasket 16, a spacer 17, and a case 18. In the electricity storage device 1, a laminate of a spacer 17, a negative electrode current collector 13, a negative electrode 12, a separator 14, a positive electrode 10 and a positive electrode current collector 11 is accommodated in an internal space formed by a sealing plate 15 and a case 18. It is a coin-type electricity storage device. Therefore, FIG. 1 can also be said to be a cross-sectional view of the electricity storage device 1 in the diameter direction. Note that substantially equal pressure is applied to the stacked portion of the positive electrode current collector 11, the positive electrode 10, the separator 14, the negative electrode 12, and the negative electrode current collector 13 in the electricity storage device 1.
　負極１２は、厚み１０μｍ以下の薄膜である。これにより、高速で充放電することが可能であり、高出力、高容量、および優れた繰り返し充放電寿命特性を有する蓄電デバイスが得られる。負極１２の厚みは、好ましくは５μｍ以下であり、より好ましくは２～５μｍである。 The negative electrode 12 is a thin film having a thickness of 10 μm or less. Thereby, it is possible to charge and discharge at high speed, and an electricity storage device having high output, high capacity, and excellent repeated charge / discharge life characteristics can be obtained. The thickness of the negative electrode 12 is preferably 5 μm or less, more preferably 2 to 5 μm.
　負極１２は、リチウムイオンを可逆的に吸蔵および放出可能な負極活物質からなり、実質的にバインダーなどの絶縁材料を含まない。負極活物質は、具体的には、珪素、珪素含有合金、珪素化合物、錫、錫含有合金および錫化合物から選ばれる少なくとも１つの非炭素材料である。特に容量が大きく、負極厚みを５μｍ以下に容易に薄くできるため、これらのなかでも、負極活物質は珪素であるのが好ましい。
　珪素含有合金としては、たとえば、珪素と、鉄、コバルト、アンチモン、ビスマス、鉛、ニッケル、銅、亜鉛、ゲルマニウム、インジウム、錫およびチタンから選ばれる少なくとも１種の元素との合金などが挙げられる。珪素化合物としては、珪素含有合金以外の珪素を含む化合物であれば特に制限されないが、好ましくは珪素酸化物、珪素窒化物、珪素酸窒化物などである。珪素酸化物としては、たとえば、式ＳｉＯｘ（０＜ｘ＜２）で表される酸化珪素が挙げられる。この酸化珪素は、窒素、硫黄などの元素を含んでもよい。珪素窒化物としては、たとえば、式Ｓｉ3Ｎy（３＜ｙ≦４）で表される窒化珪素が挙げられる。これらの中でも、Ｓｉ3Ｎ4が好ましい。珪素酸窒化物としては、珪素、酸素および窒素を主成分として含み、不純物として上記３種以外の元素（たとえば炭素、水素など）を含むことがある化合物を使用できる。たとえば、ＳｉＯaＮbという組成式では、ａ／ｂ＝０．２～５．０程度のものを好ましく使用できる。錫含有合金としては、たとえば、錫と、鉄、コバルト、アンチモン、ビスマス、鉛、ニッケル、銅、銀、亜鉛、タリウム、カドミウム、ガリウム、ゲルマニウム、インジウムおよび珪素から選ばれる少なくとも１種の元素との合金などが挙げられる。錫化合物としては、錫含有合金以外の錫を含む化合物であれば特に制限されないが、好ましくは錫酸化物である。錫酸化物としては、たとえば、式ＳｎＯｘ（ｘは上記に同じ）で表される酸化錫が挙げられる。この酸化錫は、窒素、硫黄などの元素を含んでもよい。 The negative electrode 12 is made of a negative electrode active material capable of reversibly occluding and releasing lithium ions, and does not substantially contain an insulating material such as a binder. Specifically, the negative electrode active material is at least one non-carbon material selected from silicon, a silicon-containing alloy, a silicon compound, tin, a tin-containing alloy, and a tin compound. In particular, since the capacity is large and the negative electrode thickness can be easily reduced to 5 μm or less, the negative electrode active material is preferably silicon.
Examples of the silicon-containing alloy include an alloy of silicon and at least one element selected from iron, cobalt, antimony, bismuth, lead, nickel, copper, zinc, germanium, indium, tin, and titanium. The silicon compound is not particularly limited as long as it is a compound containing silicon other than a silicon-containing alloy, but silicon oxide, silicon nitride, silicon oxynitride and the like are preferable. Examples of the silicon oxide include silicon oxide represented by the formula SiOx (0 <x <2). This silicon oxide may contain elements such as nitrogen and sulfur. Examples of the silicon nitride include silicon nitride represented by the formula Si 3 N y (3 <y ≦ 4). Among these, Si 3 N 4 is preferable. As the silicon oxynitride, a compound that contains silicon, oxygen, and nitrogen as main components and may contain an element other than the above three elements (such as carbon and hydrogen) as impurities can be used. For example, in the composition formula of SiO a N b , a / b = about 0.2 to 5.0 can be preferably used. Examples of the tin-containing alloy include tin and at least one element selected from iron, cobalt, antimony, bismuth, lead, nickel, copper, silver, zinc, thallium, cadmium, gallium, germanium, indium, and silicon. An alloy etc. are mentioned. Although it will not restrict | limit especially if it is a compound containing tin other than a tin containing alloy as a tin compound, Preferably it is a tin oxide. Examples of the tin oxide include tin oxide represented by the formula SnOx (x is the same as above). This tin oxide may contain elements such as nitrogen and sulfur.
　これらの非炭素材料はさらに非金属元素を含んでもよい。非金属元素としては特に制限されないが、たとえば、水素、ナトリウム、カリウム、ルビジウムなどのアルカリ金属、マグネシウム、カルシウムなどのアルカリ土類金属、炭素、ホウ素、窒素、リンなどが挙げられる。
　これらの非炭素材料の中でも、珪素化合物が好ましく、珪素酸化物がさらに好ましく、式ＳｉＯｘ（ｘは上記に同じ）で表される酸化珪素が特に好ましい。非炭素材料は１種を単独で使用できまたは必要に応じて２種以上を組み合わせて使用できる。 These non-carbon materials may further contain a non-metallic element. Although it does not restrict | limit especially as a nonmetallic element, For example, alkali metals, such as hydrogen, sodium, potassium, and rubidium, alkaline earth metals, such as magnesium and calcium, carbon, boron, nitrogen, phosphorus etc. are mentioned.
Among these non-carbon materials, silicon compounds are preferable, silicon oxides are more preferable, and silicon oxide represented by the formula SiOx (x is the same as above) is particularly preferable. A non-carbon material can be used individually by 1 type, or can be used in combination of 2 or more type as needed.
　これらの非炭素材料はエネルギー量が非常に大きいという特徴を有する。従来から負極活物質として使用される炭素材料（以下、「従来の炭素材料」とする）の体積当りのエネルギー密度が５００～６００ｍＡｈ／ｃｃであるのに対し、たとえば、珪素２４００ｍＡｈ／ｃｃ、錫酸化物１４００ｍＡｈ／ｃｃと、３～５倍のエネルギー密度を有する。よって、従来の炭素材料を用いる場合とは異なり、正極１０および負極１２の厚みバランスを適宜調整することが可能になる。たとえば、厚み数μｍ程度の薄膜状の負極１２を設けることが可能になる。負極１２を非炭素材料で薄膜状に形成することによって、蓄電デバイス１の高出力化とともに、小型化、高容量化などが可能になる。また、非炭素材料は、活性炭などの電気二重層キャパシタの正極活物質が３０ｍＡｈ／ｃｃ程度の体積エネルギー密度であることから、これに比べても５０～８０倍程度の非常に大きなエネルギー密度を有する。また、非炭素材料は、従来の炭素材料と同様に負極電位が低いので、３Ｖ程度の高電圧を有する蓄電デバイス１が得られる。 These non-carbon materials are characterized by a very large amount of energy. The energy density per volume of the carbon material conventionally used as the negative electrode active material (hereinafter referred to as “conventional carbon material”) is 500 to 600 mAh / cc, whereas for example silicon 2400 mAh / cc, tin oxide 1400 mAh / cc, 3-5 times energy density. Therefore, unlike the case of using a conventional carbon material, the thickness balance between the positive electrode 10 and the negative electrode 12 can be appropriately adjusted. For example, it is possible to provide a thin film-like negative electrode 12 having a thickness of about several μm. By forming the negative electrode 12 in a thin film shape using a non-carbon material, it is possible to increase the output of the electricity storage device 1 as well as to reduce the size and increase the capacity. In addition, the non-carbon material has a very large energy density of about 50 to 80 times that of the positive electrode active material of an electric double layer capacitor such as activated carbon having a volume energy density of about 30 mAh / cc. . Further, since the non-carbon material has a low negative electrode potential as in the case of the conventional carbon material, the electricity storage device 1 having a high voltage of about 3 V can be obtained.
　薄膜状の負極１２を負極集電体１３表面に直接形成するには、たとえば、真空蒸着法、スパッタリング法、ガスデポジション法、ＣＶＤ法、めっき法などの一般的な成膜方法を利用できる。このとき、成膜条件を適宜選択することによって、負極厚みを調整できる。非炭素材料と無機化合物とを含む負極を形成する場合、無機化合物の特性に応じて、成膜方法を適宜選択すればよい。たとえば、無機化合物が蒸着可能な化合物であれば、非炭素材料と無機化合物との共蒸着によって負極を形成することができる。本実施の形態では、図２に示すように、負極集電体１３表面の全面に負極１２を形成するが、それに限定されず、負極集電体１３表面にパターン状に負極１２を形成しても良い。パターンに形成した負極としては、たとえば、図３に示す負極１２ａが挙げられる。図３は、負極集電体１３表面に形成された別形態の負極１２ａの構成を模式的に示す縦断面図である。負極１２ａは、負極集電体１３表面に縞状に形成される。これに限定されず、たとえば、格子状、円形の縞状などのパターン状に形成してもよい。負極集電体１３上にパターン状に負極１２を形成する方法としては、たとえば、マスクを用いて負極１２の成膜を行う方法、表面に凹凸を有する負極集電体１３に対して斜方蒸着を行う方法、負極集電体１３の表面全面に負極１２を形成した後、エッチングなどによって負極１２を部分的に除去する方法などが挙げられる。 In order to directly form the thin-film negative electrode 12 on the surface of the negative electrode current collector 13, for example, a general film forming method such as a vacuum deposition method, a sputtering method, a gas deposition method, a CVD method, or a plating method can be used. At this time, the thickness of the negative electrode can be adjusted by appropriately selecting the film forming conditions. In the case of forming a negative electrode including a non-carbon material and an inorganic compound, a film forming method may be appropriately selected according to the characteristics of the inorganic compound. For example, if the inorganic compound can be deposited, the negative electrode can be formed by co-evaporation of a non-carbon material and an inorganic compound. In this embodiment, as shown in FIG. 2, the negative electrode 12 is formed on the entire surface of the negative electrode current collector 13. However, the present invention is not limited to this, and the negative electrode 12 is formed in a pattern on the negative electrode current collector 13 surface. Also good. Examples of the negative electrode formed in the pattern include a negative electrode 12a shown in FIG. FIG. 3 is a longitudinal sectional view schematically showing the configuration of another form of negative electrode 12 a formed on the surface of the negative electrode current collector 13. The negative electrode 12 a is formed in a striped pattern on the surface of the negative electrode current collector 13. It is not limited to this, For example, you may form in pattern shapes, such as a grid | lattice form and circular stripe form. As a method of forming the negative electrode 12 in a pattern on the negative electrode current collector 13, for example, a method of forming the negative electrode 12 using a mask, oblique deposition on the negative electrode current collector 13 having irregularities on the surface And a method of partially removing the negative electrode 12 by etching or the like after the negative electrode 12 is formed on the entire surface of the negative electrode current collector 13.
　負極１２は、好ましくは比表面積５以上、より好ましくは１０以上の薄膜状に形成される。比表面積が５未満では、蓄電デバイス１の高出力時における容量低下が顕著になり、安定的な高出力が得られないおそれがある。なお、比表面積の上限はないが、現状では１０程度のものが形成可能である。
　負極１２の比表面積は、たとえば、真空蒸着法、スパッタリング法などの一般的な成膜方法に従って負極を作製する場合、成膜条件を適宜選択することによって調整できる。 The negative electrode 12 is preferably formed in a thin film shape having a specific surface area of 5 or more, more preferably 10 or more. If the specific surface area is less than 5, the capacity drop at the time of high output of the electricity storage device 1 becomes remarkable, and there is a possibility that stable high output cannot be obtained. In addition, although there is no upper limit of the specific surface area, about 10 can be formed at present.
The specific surface area of the negative electrode 12 can be adjusted, for example, by appropriately selecting the film forming conditions when the negative electrode is produced according to a general film forming method such as a vacuum deposition method or a sputtering method.
　本明細書において、比表面積は、設定される測定範囲の表面積と、測定範囲の見掛け上の面積との比（測定範囲の表面積／測定範囲の見掛け上の面積）を意味する。測定範囲の表面積は、レーザー顕微鏡（商品名：超深度形状測定顕微鏡ＶＫ－８５５、キーエンス社製）を用いて測定される。物質の表面積の測定方法には、物質の外郭面積のみを測定する方法、物質の外郭面積と物質表面の凹凸、亀裂の面積とを測定する方法、物質の外郭面積および物質表面の凹凸、亀裂の面積とともに、物質内部に延びる細孔の面積を測定する方法などがある。そして、測定方法に応じて異なる意義を有する比表面積が求められる。レーザーを利用する表面積測定方法は、測定対象を破壊することなく、測定範囲の表面積（物質の外郭面積と物質表面の凹凸、亀裂の面積との和）を簡便に測定できる。さらに、レーザーを利用する表面積測定方法は、比表面積値が３～１０程度の物質の表面積をほぼ正確に測定できるという利点を有する。したがって、本発明において負極１２、負極集電体１３などの表面積を測定するのに好適である。一方、測定範囲の見掛け上の面積とは、測定範囲を平面と仮定した場合の面積である。したがって、見掛け上の面積は測定範囲を設定することによって自動的に算出できる。なお、本発明の測定方法では、測定範囲を鉛直方向上方から見たときに、影になって見えない部分の凹凸および亀裂は測定には含まれない。ここで「見えない」とはレーザー顕微鏡によって認識されないことである。 In the present specification, the specific surface area means the ratio of the surface area of the set measurement range to the apparent area of the measurement range (surface area of the measurement range / apparent area of the measurement range). The surface area of the measurement range is measured using a laser microscope (trade name: Ultra-deep shape measurement microscope VK-855, manufactured by Keyence Corporation). The method for measuring the surface area of a substance includes the method of measuring only the outer area of the substance, the method of measuring the outer area of the substance and the unevenness of the substance surface, the area of the crack, the outer area of the substance and the unevenness of the substance surface, the crack There is a method of measuring the area of pores extending inside the substance together with the area. And the specific surface area which has a different meaning according to a measuring method is calculated | required. The surface area measurement method using a laser can easily measure the surface area of the measurement range (the sum of the outer area of the substance and the unevenness of the substance surface and the area of the crack) without destroying the measurement object. Furthermore, the surface area measuring method using a laser has an advantage that the surface area of a substance having a specific surface area value of about 3 to 10 can be measured almost accurately. Therefore, the present invention is suitable for measuring the surface area of the negative electrode 12, the negative electrode current collector 13, and the like. On the other hand, the apparent area of the measurement range is an area when the measurement range is assumed to be a plane. Therefore, the apparent area can be automatically calculated by setting the measurement range. Note that, in the measurement method of the present invention, when the measurement range is viewed from above in the vertical direction, the unevenness and cracks that are not visible as shadows are not included in the measurement. Here, “invisible” means not recognized by the laser microscope.
　測定範囲は、次のように設定される。まず、測定対象物質の表面から１つの突起を選択し、これを第１の突起とする。第１の突起周縁部の各辺の幅をＷとする。Ｗの値は実際には辺ごとに変化する。次に、第１の突起の中心部において、第１の突起と相似形であり、周縁部の各辺の幅がＷ／２以下である部分を測定範囲とする。 The measurement range is set as follows. First, one projection is selected from the surface of the substance to be measured, and this is set as the first projection. Let W be the width of each side of the peripheral edge of the first protrusion. The value of W actually changes from side to side. Next, in the central portion of the first protrusion, a portion that is similar to the first protrusion and the width of each side of the peripheral edge portion is W / 2 or less is set as a measurement range.
　また、負極集電体１３の負極１２が形成される面の表面粗さ（算術平均表面粗さ）Ｒａの値（ラフネス値）を特定の範囲に調整することによっても、所定の厚みおよび比表面積を有する負極１２を形成できる。負極集電体１３の表面粗さＲａを調整すれば、成膜条件を厳密に調整しないでも、所定の比表面積を有する負極１２を容易に形成できる。このとき、負極集電体１３の表面粗さＲａの値が、負極１２の厚みと同じかまたはそれよりも大きい値であることが好ましい。換言すれば、形成直後のリチウムを全く含まない負極１２の厚みが、負極集電体１３の表面粗さＲａの値以下であることが好ましい。これによって、負極集電体１３表面の凹凸が負極１２表面にほぼ正確に再現され、所定の比表面積を有する負極１２が得られる。負極１２の厚みが、負極集電体１３の表面粗さＲａの値を超えると、負極集電体１３表面の凹凸に対する負極１２の追従性がなくなる。その結果、負極集電体１３表面の凹凸が負極１２によって平坦化され、所定の比表面積を有する負極１２が得られないおそれがある。負極集電体１３の表面粗さＲａは、好ましくは１０μｍ以下、より好ましくは５μｍ以下、さらに好ましくは１～２μｍである。負極集電体１３の表面粗さＲａは、たとえば、一般的な粗面化処理方法などによって適宜調整できる。本明細書において、負極集電体１３の表面粗さＲａは、日本工業規格のＪＩＳ　Ｂ０６０１－１９９４に規定される方法によって測定される値である。 The predetermined thickness and specific surface area can also be obtained by adjusting the value (roughness value) of the surface roughness (arithmetic average surface roughness) Ra of the surface of the negative electrode current collector 13 on which the negative electrode 12 is formed. Can be formed. By adjusting the surface roughness Ra of the negative electrode current collector 13, the negative electrode 12 having a predetermined specific surface area can be easily formed without strictly adjusting the film forming conditions. At this time, the value of the surface roughness Ra of the negative electrode current collector 13 is preferably equal to or greater than the thickness of the negative electrode 12. In other words, it is preferable that the thickness of the negative electrode 12 containing no lithium immediately after formation is equal to or less than the value of the surface roughness Ra of the negative electrode current collector 13. As a result, the irregularities on the surface of the negative electrode current collector 13 are almost accurately reproduced on the surface of the negative electrode 12, and the negative electrode 12 having a predetermined specific surface area is obtained. When the thickness of the negative electrode 12 exceeds the value of the surface roughness Ra of the negative electrode current collector 13, the followability of the negative electrode 12 to the irregularities on the surface of the negative electrode current collector 13 is lost. As a result, the unevenness on the surface of the negative electrode current collector 13 is flattened by the negative electrode 12, and the negative electrode 12 having a predetermined specific surface area may not be obtained. The surface roughness Ra of the negative electrode current collector 13 is preferably 10 μm or less, more preferably 5 μm or less, and further preferably 1 to 2 μm. The surface roughness Ra of the negative electrode current collector 13 can be appropriately adjusted by, for example, a general surface roughening method. In this specification, the surface roughness Ra of the negative electrode current collector 13 is a value measured by a method defined in JIS B0601-1994 of the Japanese Industrial Standard.
　さらに、負極集電体１３の負極１２が形成される面の比表面積を好ましくは５以上、より好ましくは１０以上に調整することによっても、所定の厚みおよび比表面積を有する負極１２を比較的容易に形成できる。このときも、負極１２の厚みが、負極集電体１３の表面粗さＲａの値以下になるように、たとえば、成膜時間などの成膜条件を適宜選択するのがよい。 Further, the negative electrode 12 having a predetermined thickness and specific surface area can be relatively easily adjusted by adjusting the specific surface area of the negative electrode current collector 13 on which the negative electrode 12 is formed to preferably 5 or more, more preferably 10 or more. Can be formed. Also at this time, it is preferable to appropriately select film formation conditions such as film formation time so that the thickness of the negative electrode 12 is equal to or less than the value of the surface roughness Ra of the negative electrode current collector 13.
　蓄電デバイスの充放電時において、負極のＳＯＣ（state of charge）は２０％以上９５％以下であるのが好ましい。これにより、高容量および高出力を有し、かつ充放電繰り返し寿命特性に優れた蓄電デバイスが得られる。
　なお、負極のＳＯＣとは、蓄電デバイスとしてではなく、負極単体の充電状態を表す指標であり、負極単体の満充電時の容量（可逆容量）を１００％として、満充電量に対する充電量の割合を百分率で表した値である。従って、完全に放電された状態のＳＯＣは０％であり、満充電状態のＳＯＣは１００％である。
　負極のＳＯＣは、以下の方法により求められる。リチウム基準で０～１．５Ｖの電位範囲において、負極容量に対して０．２ＣＡ（５時間率）で充電させた場合の負極の充電量をＳＯＣが１００％である（満充電である）と定義し、この充電量を基準としてＳＯＣの値を求めることができる。 At the time of charge / discharge of the electricity storage device, the SOC (state of charge) of the negative electrode is preferably 20% or more and 95% or less. Thereby, the electrical storage device which has high capacity | capacitance and high output, and was excellent in the charging / discharging repetition lifetime characteristic is obtained.
The SOC of the negative electrode is an index that represents the state of charge of the single negative electrode, not as a power storage device, and the ratio of the charge amount to the full charge amount with the capacity (reversible capacity) when the negative electrode is fully charged being 100%. Is a value expressed as a percentage. Therefore, the fully discharged SOC is 0%, and the fully charged SOC is 100%.
The SOC of the negative electrode is determined by the following method. In the potential range of 0 to 1.5 V with respect to lithium, the SOC of the negative electrode when charged at 0.2 CA (5-hour rate) with respect to the negative electrode capacity is 100% (full charge) The SOC value can be determined based on this charge amount.
　負極集電体１３は、図４および図５に示すように、膜状の負極集電体１３を厚み方向に貫通する複数の貫通孔２０を有し、この貫通孔２０が電解質保持部になる。負極集電体１３の内部には、主に負極集電体１３の厚み方向に延びる複数の連続気泡２１が存在する。連続気泡２１の一端は負極集電体１３の厚み方向における一方の表面に達し、連続気泡２１の他端は負極集電体１３の厚み方向における他方の表面に達する。連続気泡２１は複数の気泡が連続的に繋がり、個々の気泡は内部空間を有するので、連続気泡２１の内部では個々の気泡の内部空間が連通して１つの貫通孔２０が形成される。 As shown in FIGS. 4 and 5, the negative electrode current collector 13 has a plurality of through holes 20 that penetrate the film-like negative electrode current collector 13 in the thickness direction, and the through holes 20 serve as an electrolyte holding portion. . Inside the negative electrode current collector 13, there are a plurality of open cells 21 extending mainly in the thickness direction of the negative electrode current collector 13. One end of the open cell 21 reaches one surface in the thickness direction of the negative electrode current collector 13, and the other end of the open cell 21 reaches the other surface in the thickness direction of the negative electrode current collector 13. A plurality of bubbles are continuously connected to each other in the continuous bubble 21, and each bubble has an internal space. Therefore, inside the continuous bubble 21, the internal space of each bubble communicates to form one through hole 20.
　貫通孔２０を有することにより、この貫通孔２０の中に電解液を含浸および保持させることができる。すなわち、負極１２に接して設けられる負極集電体１３内部に、アニオン、カチオンの電解質（電解液）を保持できる。負極１２がその内部に電解質を充分に保持できなくても、負極集電体１３内部に充分な量の電解質を保持することにより、蓄電デバイス１内部に必要な量の電解質を確保することができる。図５では、複数の貫通孔２０を有する負極集電体１３における厚み方向の一方の面に、負極１２が形成される。負極１２が負極集電体１３上に成膜された後も、貫通孔２０を通して、負極集電体１３内部に電解質を含浸および保持させるには、好ましくは、負極１２の厚みを貫通孔２０の孔径よりも小さくするのがよい。換言すれば、貫通孔２０の孔径は、負極１２の厚みよりも大きいことが好ましい。具体的には、貫通孔２０の孔径は、好ましくは負極１２の厚みの２倍以上、より好ましくは５倍以上、さらに好ましくは５倍～１００倍である。なお、貫通孔２０の孔径は、たとえばガス吸着測定あるいは水銀ポロシメータにより測定することができる。また、貫通孔２０の孔径は、一般的に分布を持っていることが多いため、体積基準メディアン細孔径を代表値として、貫通孔２０の孔径として扱うことができる。 By having the through hole 20, the electrolytic solution can be impregnated and held in the through hole 20. That is, an anion and cation electrolyte (electrolytic solution) can be held inside the negative electrode current collector 13 provided in contact with the negative electrode 12. Even if the negative electrode 12 cannot sufficiently hold the electrolyte therein, a sufficient amount of electrolyte can be secured inside the electricity storage device 1 by holding a sufficient amount of electrolyte inside the negative electrode current collector 13. . In FIG. 5, the negative electrode 12 is formed on one surface in the thickness direction of the negative electrode current collector 13 having a plurality of through holes 20. In order to impregnate and hold the electrolyte in the negative electrode current collector 13 through the through hole 20 even after the negative electrode 12 is formed on the negative electrode current collector 13, the thickness of the negative electrode 12 is preferably set to the thickness of the through hole 20. It is better to make it smaller than the hole diameter. In other words, the hole diameter of the through hole 20 is preferably larger than the thickness of the negative electrode 12. Specifically, the hole diameter of the through hole 20 is preferably at least twice the thickness of the negative electrode 12, more preferably at least 5 times, and even more preferably at 5 to 100 times. In addition, the hole diameter of the through-hole 20 can be measured by, for example, gas adsorption measurement or a mercury porosimeter. Moreover, since the hole diameter of the through-hole 20 generally has a distribution, it can be handled as the hole diameter of the through-hole 20 with the volume-based median pore diameter as a representative value.
　負極集電体１３の占有体積に対する電解質保持部の容積（貫通孔２０の内部容積の総和）の割合（以下、単に「電解液保持部の容積比率」とする）は、３０％以上であるのが好ましい。
　電解質保持部の容積比率は、より好ましくは５０％以上、さらに好ましくは５０～９５％である。電解質保持部の容積比率が３０％未満では、負極１２近傍における電解質塩量が不十分になり、蓄電デバイス１の充放電容量が低下する場合がある。なお、電解質保持部の容積比率の測定には、たとえばガス吸着測定あるいは水銀ポロシメータにより測定することができる。ガス吸着測定の例としては、比表面積・細孔分布測定器（商品名：ＡＳＡＰ２０１０、（株）島津製作所製）を用いる測定が一例として挙げられる。この測定装置はガスの吸脱着を利用して細孔容積を測定する装置であり、数Å～０．１μｍ程度の細孔径を有する細孔の測定が可能である。また、別の一例としては水銀ポロシメータ（商品名：オートポアIII９４１０、（株）島津製作所製）を用いる測定が一例として挙げられる。この測定装置は細孔への水銀の圧入を利用して細孔容積を測定する装置であり、数ｎｍ～５００μｍ程度の細孔径を有する細孔の測定が可能である。これら測定装置は、対象物の細孔径に応じて使い分けることができる。 The ratio of the volume of the electrolyte holding portion (the sum of the internal volumes of the through holes 20) to the volume occupied by the negative electrode current collector 13 (hereinafter simply referred to as “volume ratio of the electrolyte holding portion”) is 30% or more. Is preferred.
The volume ratio of the electrolyte holding portion is more preferably 50% or more, and further preferably 50 to 95%. When the volume ratio of the electrolyte holding part is less than 30%, the amount of electrolyte salt in the vicinity of the negative electrode 12 becomes insufficient, and the charge / discharge capacity of the electricity storage device 1 may be reduced. The volume ratio of the electrolyte holding part can be measured, for example, by gas adsorption measurement or mercury porosimeter. As an example of the gas adsorption measurement, a measurement using a specific surface area / pore distribution measuring instrument (trade name: ASAP2010, manufactured by Shimadzu Corporation) is given as an example. This measuring device is a device that measures the pore volume by using gas adsorption and desorption, and can measure pores having a pore diameter of about several to 0.1 μm. Another example is measurement using a mercury porosimeter (trade name: Autopore III 9410, manufactured by Shimadzu Corporation). This measuring device is a device that measures the pore volume by using mercury intrusion into the pores, and can measure pores having a pore diameter of about several nm to 500 μm. These measuring devices can be used properly according to the pore diameter of the object.
　貫通孔２０を有する負極集電体１３としては、たとえば、発泡体、メッシュ体などの多孔質体を使用できる。また、負極集電体１３を構成する素材としては、リチウムイオン電池の負極集電体に用いられるものを使用できるが、多孔質化の加工性などを考慮すると、銅、ニッケルなどの金属素材が好ましい。なお、発泡体では、発泡体内部に形成される連続気泡が電解質保持部であり、連続気泡の容積の総和が電解質保持部の容積であり、発泡体の空隙率が負極集電体１３の占有体積に対する電解質保持部の容積比率になる。 As the negative electrode current collector 13 having the through holes 20, for example, a porous body such as a foam or a mesh body can be used. Moreover, as a material which comprises the negative electrode collector 13, what is used for the negative electrode collector of a lithium ion battery can be used, However, considering the workability of porous formation etc., metal materials, such as copper and nickel, are used. preferable. In the foam, the open cell formed inside the foam is the electrolyte holding part, the total volume of the open cells is the volume of the electrolyte holding part, and the porosity of the foam is occupied by the negative electrode current collector 13. This is the volume ratio of the electrolyte holding part to the volume.
　ここで、図６は、別形態の負極集電体３０の構成を模式的に示す縦断面図である。図７は、薄膜負極３３と図６に示す負極集電体３０とからなる負極積層体の構成を模式的に示す縦断面図である。負極集電体３０は、集電膜３１と、突起３２とを含むことを特徴とする。集電膜３１は、リチウムイオン電池の負極集電体に用いられる素材で構成される。突起３２は、集電膜３１の厚み方向の両面に、集電膜３１表面から集電膜３１の外方に向けて延びるように、複数形成される。集電膜３１は、厚み方向に貫通する貫通孔を有しない。 Here, FIG. 6 is a longitudinal sectional view schematically showing the configuration of another form of negative electrode current collector 30. FIG. 7 is a longitudinal sectional view schematically showing a configuration of a negative electrode laminate including the thin film negative electrode 33 and the negative electrode current collector 30 shown in FIG. The negative electrode current collector 30 includes a current collecting film 31 and a protrusion 32. The current collecting film 31 is made of a material used for a negative electrode current collector of a lithium ion battery. A plurality of protrusions 32 are formed on both surfaces of the current collecting film 31 in the thickness direction so as to extend from the surface of the current collecting film 31 toward the outside of the current collecting film 31. The current collecting film 31 does not have a through hole penetrating in the thickness direction.
　負極集電体３０においては、少なくとも突起３２の先端部に負極３３が形成される。この負極集電体３０とセパレータ１４とを、負極３３を介して接触させると、突起３２の存在により、負極集電体３０とセパレータ１４とが直接接触しない空間が形成される。この空間に電解質を含浸および保持させることにより、負極３３近傍で負極反応に必要な電解質塩量を確保できる。すなわち、この空間が電解質保持部になる。
　電解質保持部の容積は、集電体面積に対する突起の非占有面積と、突起高さを掛けることにより、計算により算出することができる。ここで、集電体面積に対する突起の非占有面積とは、集電体膜の面積において、集電体表面に突起が形成されていない部分の総面積の割合である。突起高さ、および集電体面積に対する突起の非占有面積は、レーザー顕微鏡あるいは電子顕微鏡を用いた、集電体膜の表面観察、および断面観察により測定することができる。具体的には、たとえば、レーザー顕微鏡（商品名：ＶＫ－８５５、キーエンス社製）などを用いることができる。 In the negative electrode current collector 30, the negative electrode 33 is formed at least at the tip of the protrusion 32. When the negative electrode current collector 30 and the separator 14 are brought into contact with each other via the negative electrode 33, a space in which the negative electrode current collector 30 and the separator 14 are not in direct contact is formed due to the presence of the protrusion 32. By impregnating and holding the electrolyte in this space, the amount of electrolyte salt necessary for the negative electrode reaction can be secured in the vicinity of the negative electrode 33. That is, this space becomes an electrolyte holding part.
The volume of the electrolyte holding portion can be calculated by multiplying the non-occupied area of the protrusion with respect to the current collector area by the protrusion height. Here, the non-occupied area of the protrusions with respect to the current collector area is the ratio of the total area of the area where the protrusions are not formed on the current collector surface in the area of the current collector film. The protrusion height and the unoccupied area of the protrusion relative to the current collector area can be measured by surface observation and cross-sectional observation of the current collector film using a laser microscope or an electron microscope. Specifically, for example, a laser microscope (trade name: VK-855, manufactured by Keyence Corporation) can be used.
　突起３２は、その表面に設けられる負極３３を介して、点ではなく面でセパレータ１４に接触するように形成するのが好ましい。したがって、突起３２は、好ましくはその先端（集電膜３１から最も遠い部分）が面になるように形成され、さらに好ましくはその先端が集電膜３１表面に平行な面になるように形成される。突起３２の先端が面になることによって、その先端面がセパレータ１４を確実に支持するので、蓄電デバイス１の耐用期間全般にわたって、電解質保持部の容積がほぼ同じに保持される。また、突起３２の先端がセパレータ１４を貫通して正負極を短絡させ、蓄電デバイス１の製品歩留まりを低下させることがない。突起３２は、先端が面であればそれ以外の形状は特に制限されず、種々の形状に形成することが可能である。ただし、セパレータ１４の安定的に支持することなどを考慮すると、負極集電体３０の厚み方向の断面形状が台形状または擬台形状になるように形成するのが好ましい。擬台形状とは、厚み方向の断面がほぼ台形に近い形状であり、集電膜３１から遠い方の辺（以下「上辺」とする）よりも集電膜３１表面に接触する辺（以下「下辺」とする）が長くかつ上辺が下辺に対してわずかに平行でない形状である。この場合、上辺の延長線と下辺の延長線とがなす角の角度は数度程度である。また、厚み方向の断面における上辺の少なくとも一部が曲線を含んでいてもよい。擬台形状であっても、面でセパレータ１４を支持できれば、前記のような効果が得られる。 The protrusion 32 is preferably formed so as to be in contact with the separator 14 not by a point but by a surface through a negative electrode 33 provided on the surface thereof. Accordingly, the protrusion 32 is preferably formed such that its tip (the portion farthest from the current collector film 31) is a surface, and more preferably, its tip is a surface parallel to the surface of the current collector film 31. The When the tip of the protrusion 32 becomes a surface, the tip surface reliably supports the separator 14, so that the volume of the electrolyte holding portion is held substantially the same throughout the lifetime of the electricity storage device 1. Further, the tip of the protrusion 32 does not penetrate the separator 14 to short-circuit the positive and negative electrodes, and the product yield of the electricity storage device 1 is not reduced. The protrusion 32 is not particularly limited in shape as long as the tip is a surface, and can be formed in various shapes. However, in consideration of the stable support of the separator 14, it is preferable to form the negative electrode current collector 30 so that the cross-sectional shape in the thickness direction is a trapezoidal shape or a pseudo-trapezoidal shape. The pseudo trapezoidal shape is a shape in which the cross section in the thickness direction is almost a trapezoid, and the side (hereinafter referred to as “the upper side”) in contact with the surface of the current collecting film 31 rather than the side farther from the current collecting film 31 (hereinafter referred to as “upper side”). The lower side ”is long and the upper side is not slightly parallel to the lower side. In this case, the angle formed by the extension line on the upper side and the extension line on the lower side is about several degrees. Further, at least a part of the upper side in the cross section in the thickness direction may include a curve. Even if it is a pseudo trapezoid shape, the above-described effects can be obtained if the separator 14 can be supported by the surface.
　ここで、さらに別形態の負極集電体３５の構成を模式的に示す縦断面図を図８に示す。負極集電体３５は、図８に示すように、突起３６の厚み方向断面形状が三角形であり、突起３６の先端は尖って点になる。突起３６の先端が点であると、その先端の少なくとも一部がセパレータ１４内に侵入し、場合によってセパレータ１４を貫通するおそれがある。また、突起３６の先端がセパレータ１４を貫通して正負極を短絡させ、蓄電デバイス１の製品歩留まりを低下させるおそれがある。
　負極集電体３０の占有体積は、集電膜３１の厚み方向表面の面積と負極集電体３０の厚みｔとを乗じた値である。ここで、負極集電体３０の厚みｔは、集電膜３１の一方の面に形成される突起３２の最頂部から他方の面に形成される突起３２の最頂部までの長さを言う。負極集電体３０の占有体積に対する電解質保持部の割合を３０％以上にするためには、たとえば、突起３２の高さ、突起３２の先端に形成される面の面積の総和、突起３２同士の間隔、突起３２の数などを適宜調整すればよい。突起３２の高さとは、集電膜３１表面から突起３２の最頂部までの長さを言う。 Here, FIG. 8 is a longitudinal sectional view schematically showing the configuration of the negative electrode current collector 35 of still another embodiment. As shown in FIG. 8, in the negative electrode current collector 35, the protrusion 36 has a triangular cross-sectional shape in the thickness direction, and the tip of the protrusion 36 has a sharp point. If the tip of the protrusion 36 is a point, at least a part of the tip may enter the separator 14 and possibly penetrate the separator 14. In addition, the tip of the protrusion 36 may penetrate the separator 14 to short-circuit the positive and negative electrodes, which may reduce the product yield of the electricity storage device 1.
The occupied volume of the negative electrode current collector 30 is a value obtained by multiplying the surface area of the current collector film 31 in the thickness direction by the thickness t of the negative electrode current collector 30. Here, the thickness t of the negative electrode current collector 30 refers to the length from the top of the protrusion 32 formed on one surface of the current collector film 31 to the top of the protrusion 32 formed on the other surface. In order to set the ratio of the electrolyte holding portion to the occupied volume of the negative electrode current collector 30 to 30% or more, for example, the height of the protrusion 32, the total area of the surface formed at the tip of the protrusion 32, What is necessary is just to adjust a space | interval, the number of the protrusions 32, etc. suitably. The height of the protrusion 32 refers to the length from the surface of the current collecting film 31 to the top of the protrusion 32.
　負極集電体３０は、たとえば、集電膜３１に機械的加工を施し、集電膜３１の厚み方向の表面に複数の突起３２を形成することによって製造できる。機械的加工とは、たとえば、プレス加工、ローラー加工などである。また、集電膜３１に、研磨、エッチング、パターニングなどの表面加工、めっき処理（電解めっき、無電解めっき、電着めっきなど）、微粒子の吹き付け処理などを施すことによっても、負極集電体３０を得ることができる。ここで、集電膜３１には、たとえば、銅箔、ニッケル箔などを使用できる。 The negative electrode current collector 30 can be manufactured, for example, by subjecting the current collector film 31 to mechanical processing and forming a plurality of protrusions 32 on the surface of the current collector film 31 in the thickness direction. The mechanical processing is, for example, press processing or roller processing. The negative electrode current collector 30 can also be obtained by subjecting the current collecting film 31 to surface processing such as polishing, etching, patterning, plating treatment (electrolytic plating, electroless plating, electrodeposition plating, etc.), and fine particle spraying treatment. Can be obtained. Here, for the current collecting film 31, for example, a copper foil, a nickel foil or the like can be used.
　また、負極集電体３０表面に負極３３を形成するに際しては、負極３３の厚みと突起３２の高さとの関係に留意するのが好ましい。図７に示すように、負極３３が負極集電体３０表面の形状を追従するように形成され、負極３３表面に突起３２の形状が再現されるのが好ましい。これにより、負極３３の形成後も、負極３３表面に、電解質を保持するための空間である電解質保持部を確保できる。したがって、負極集電体３０表面に存在する突起３２の高さに対して負極３３の厚みが十分に薄いことが必要である。具体的には、突起３２の高さを、好ましくは負極３３の厚みの２倍以上、より好ましく負極３３の厚みの５倍以上、さらに好ましくは５～１０倍にするのがよい。 In forming the negative electrode 33 on the surface of the negative electrode current collector 30, it is preferable to pay attention to the relationship between the thickness of the negative electrode 33 and the height of the protrusion 32. As shown in FIG. 7, the negative electrode 33 is preferably formed so as to follow the shape of the surface of the negative electrode current collector 30, and the shape of the protrusion 32 is preferably reproduced on the surface of the negative electrode 33. Thereby, even after formation of the negative electrode 33, an electrolyte holding portion that is a space for holding the electrolyte can be secured on the surface of the negative electrode 33. Therefore, the thickness of the negative electrode 33 needs to be sufficiently thin with respect to the height of the protrusion 32 existing on the surface of the negative electrode current collector 30. Specifically, the height of the protrusion 32 is preferably at least twice the thickness of the negative electrode 33, more preferably at least five times the thickness of the negative electrode 33, and further preferably 5 to 10 times.
　突起３２の高さが、負極３３の厚みの２倍未満である場合には、突起３２により確保される電解質保持部の空間が小さくなる。図９は、負極積層体４０の構成を模式的に示す縦断面図である。負極積層体４０は、負極４１と、負極集電体４２とを含む。負極集電体４２は、集電膜４３と突起４４とを含む。負極積層体４０においては、突起４４の高さが、負極４１の成膜厚みの２倍未満である。負極４１は、突起４４先端の面だけでなく、突起４４の側面にも形成されるので、特に隣り合う突起４４の間の空間が狭まる。その結果、突起４４の存在によって形成されるべき電解質保持部の空間が極端に小さくなり、負極集電体４２が保持可能な電解液量が減少する。
　なお、負極集電体３０では、厚み方向の両面に突起３２を形成するが、それに限定されず、負極集電体３０のセパレータ１４に接触する面にのみ複数の突起３２を形成してもよい。その場合は、突起３２が形成された面のみに薄膜負極３３を設けてもよい。 When the height of the protrusion 32 is less than twice the thickness of the negative electrode 33, the space of the electrolyte holding portion secured by the protrusion 32 is reduced. FIG. 9 is a longitudinal sectional view schematically showing the configuration of the negative electrode laminate 40. The negative electrode laminate 40 includes a negative electrode 41 and a negative electrode current collector 42. The negative electrode current collector 42 includes a current collector film 43 and a protrusion 44. In the negative electrode laminate 40, the height of the protrusion 44 is less than twice the film thickness of the negative electrode 41. Since the negative electrode 41 is formed not only on the front surface of the protrusion 44 but also on the side surface of the protrusion 44, the space between the adjacent protrusions 44 is particularly narrowed. As a result, the space of the electrolyte holding portion to be formed due to the presence of the protrusion 44 becomes extremely small, and the amount of electrolyte solution that can be held by the negative electrode current collector 42 is reduced.
In the negative electrode current collector 30, the protrusions 32 are formed on both surfaces in the thickness direction. However, the present invention is not limited thereto, and a plurality of protrusions 32 may be formed only on the surface of the negative electrode current collector 30 that contacts the separator 14. . In that case, the thin film negative electrode 33 may be provided only on the surface on which the protrusion 32 is formed.
　また、負極１２を負極集電体１３表面に形成した後、負極１２に所定の電気量を予め充電しておくのが好ましい。すなわち、負極１２に所定量のリチウムを予め吸蔵させておくのが好ましい。本明細書において、負極１２に電気量を予め充電するとは、蓄電デバイス１の作製（組み立て）に先立って、負極１２に電気量を充電し、負極活物質にリチウムを吸蔵させておくことである。これは、蓄電デバイス１の作製直後の負極１２が不可逆容量を有することなどによるものである。不可逆容量とは、負極１２に充電される電気容量のうち、負極活物質の充放電反応に寄与するリチウムの吸蔵・放出反応以外の副反応に消費される分に相当する容量のことをいう。すなわち、不可逆容量とは、充電したにもかかわらず、可逆的に放電できない容量であり、最初の充放電においてのみ観測されることが良く知られている。 In addition, after the negative electrode 12 is formed on the surface of the negative electrode current collector 13, it is preferable to charge the negative electrode 12 with a predetermined amount of electricity in advance. That is, it is preferable to store a predetermined amount of lithium in the negative electrode 12 in advance. In this specification, precharging the negative electrode 12 with an amount of electricity means charging the negative electrode 12 with an amount of electricity and storing the lithium in the negative electrode active material prior to the fabrication (assembly) of the electricity storage device 1. . This is because the negative electrode 12 immediately after the production of the electricity storage device 1 has an irreversible capacity. The irreversible capacity refers to a capacity corresponding to a part of the electric capacity charged in the negative electrode 12 that is consumed by a side reaction other than the occlusion / release reaction of lithium contributing to the charge / discharge reaction of the negative electrode active material. That is, the irreversible capacity is a capacity that cannot be reversibly discharged despite being charged, and is well known to be observed only in the first charge / discharge.
　負極１２に予め所定の電気量を充電するに際しては、公知の方法を採用でき、たとえば、機械的充電方法、電気化学的充電方法、化学的充電方法などが挙げられる。機械的充電方法によれば、たとえば、負極活物質よりも電位の低い材料（金属リチウムなど）を負極活物質に機械的に接触させることにより充電する。より具体的には、たとえば、負極１２表面に所定量の金属リチウムを貼り付けるか、負極１２表面に蒸着などの真空プロセスによって金属リチウムを直接成膜するか、または、離型処理を施したプラスチック基板上で作製した金属リチウムを負極１２表面に転写した後、充電すればよい。また、機械的充電方法では、負極活物質よりも電位の低い材料を負極１２表面に接触させた後に、負極１２を加熱することにより充電反応の進行を早め、充電反応の所要時間を短縮することも可能である。 When the anode 12 is charged with a predetermined amount of electricity in advance, a known method can be employed, and examples thereof include a mechanical charging method, an electrochemical charging method, a chemical charging method, and the like. According to the mechanical charging method, for example, charging is performed by mechanically bringing a material (such as lithium metal) having a lower potential than the negative electrode active material into contact with the negative electrode active material. More specifically, for example, a predetermined amount of metallic lithium is attached to the negative electrode 12 surface, or a metallic lithium film is directly formed on the negative electrode 12 surface by a vacuum process such as vapor deposition, or a release-treated plastic. The metal lithium produced on the substrate is transferred to the surface of the negative electrode 12 and then charged. In the mechanical charging method, after the material having a lower potential than the negative electrode active material is brought into contact with the surface of the negative electrode 12, the negative electrode 12 is heated to accelerate the progress of the charging reaction, thereby shortening the time required for the charging reaction. Is also possible.
　電気化学的充電方法によれば、たとえば、負極１２と対極とを電解液中に浸漬させ、負極１２と対極との間に電流を通電させることにより、負極１２を充電する。このとき、対極としては、たとえば、金属リチウムを使用できる。電解液としては、たとえば、リチウム塩を溶解させた非水溶媒を使用できる。また、リチウムイオン電池に用いられる一般的な電解液を使用してもよい。蓄電デバイス１を作製した後に、蓄電デバイス１の内部に、正極１０および負極１２以外に、負極１２に電気化学的充電処理を施すための図示しない第３の電極を導入すれば、蓄電デバイス１のセル構成後に負極１２に充電処理を施すことも可能である。
　化学的充電方法によれば、たとえば、ブチルリチウムなどのリチウムイオンを含有する化合物を有機溶媒中に溶解させ、この溶液と負極１２とを接触させ、化学反応を生起させることにより、負極１２を充電する。リチウムイオンを含有する化合物の溶液と負極１２との接触は、たとえば、該溶液中に負極１２を浸漬させることにより行われる。 According to the electrochemical charging method, for example, the negative electrode 12 and the counter electrode are immersed in an electrolytic solution, and a current is passed between the negative electrode 12 and the counter electrode, whereby the negative electrode 12 is charged. At this time, for example, metallic lithium can be used as the counter electrode. As the electrolytic solution, for example, a non-aqueous solvent in which a lithium salt is dissolved can be used. Moreover, you may use the general electrolyte solution used for a lithium ion battery. If the third electrode (not shown) for applying the electrochemical charging process to the negative electrode 12 in addition to the positive electrode 10 and the negative electrode 12 is introduced into the electric storage device 1 after the electric storage device 1 is manufactured, It is also possible to charge the negative electrode 12 after the cell configuration.
According to the chemical charging method, for example, a compound containing lithium ions such as butyl lithium is dissolved in an organic solvent, and this solution is brought into contact with the negative electrode 12 to cause a chemical reaction, thereby charging the negative electrode 12. To do. The contact between the lithium ion-containing compound solution and the negative electrode 12 is performed, for example, by immersing the negative electrode 12 in the solution.
　これらの充電方法のうち、電気化学的充電方法および化学的充電方法では、充電後に負極１２を取り出し、負極１２の表面に付着する溶媒、電解質塩その他の充電処理に用いる化合物などを洗浄により除去する必要がある。また、充電処理そのものにも長時間を要する。また、充電後の負極１２はリチウム電位に近くかつ非常に低い電位になり、反応性が高くなるため、充電後の負極１２の洗浄時に、負極１２表面が劣化する場合がある。これに対し、機械的充電方法では、負極１２にリチウムのみを接触させるため、洗浄の必要がなく、また所要時間も短い。負極１２表面の劣化もない。 Among these charging methods, in the electrochemical charging method and the chemical charging method, the negative electrode 12 is taken out after charging, and the solvent, electrolyte salt, and other compounds used for the charging treatment, which are attached to the surface of the negative electrode 12, are removed by washing. There is a need. In addition, the charging process itself takes a long time. Further, since the negative electrode 12 after charging is close to the lithium potential and has a very low potential and becomes highly reactive, the surface of the negative electrode 12 may be deteriorated during cleaning of the negative electrode 12 after charging. On the other hand, in the mechanical charging method, since only lithium is brought into contact with the negative electrode 12, there is no need for cleaning and the required time is short. There is no deterioration of the surface of the negative electrode 12.
　したがって、製造面および特性面から、機械的充電方法が好ましい。特に、機械的充電方法の中でも、負極１２表面に蒸着などの薄膜形成プロセスによって金属リチウムを直接成膜する方法が最も望ましい。なぜなら、本発明の蓄電デバイスにおける負極１２は、厚み１０μｍ以下の薄膜負極であるため、充電すべきリチウムもまた同様に、厚み１０μｍ以下、場合によっては５μｍ以下の薄膜で制御する必要があるため、金属リチウムの貼り付け処理などは事実上制御が困難となる。したがって、蒸着などの薄膜形成プロセスによる機械的充電方法が、厚み制御性、加工時間の観点から望ましい。機械的充電方法を実施することによって、蓄電デバイスの加工性が顕著に向上する。 Therefore, the mechanical charging method is preferable from the viewpoint of manufacturing and characteristics. In particular, among the mechanical charging methods, a method in which metallic lithium is directly formed on the surface of the negative electrode 12 by a thin film forming process such as vapor deposition is most desirable. Because the negative electrode 12 in the electricity storage device of the present invention is a thin film negative electrode having a thickness of 10 μm or less, the lithium to be charged also needs to be controlled with a thin film having a thickness of 10 μm or less, and in some cases, 5 μm or less. In practice, it is difficult to control the process of attaching metallic lithium. Therefore, a mechanical charging method by a thin film forming process such as vapor deposition is desirable from the viewpoint of thickness controllability and processing time. By implementing the mechanical charging method, the workability of the electricity storage device is significantly improved.
　また、負極１２に所定の電気量を充電する際においても、本発明の蓄電デバイス１における、負極集電体１３上にバインダーを含まず直接形成した負極１２が有効となる。この理由について、以下に説明する。たとえば、蒸着法により負極１２上にリチウムを成膜し、機械的充電を行う場合、リチウムの融点が１７９℃であることから、負極１２は少なくとも１７９℃前後の高温に加熱されたリチウムに曝されることになる。この際、バインダーを含む負極上にリチウムを成膜すると、バインダーの主成分として用いられる樹脂材料の多くは、リチウムのように化学的な反応性に富みかつ１７９℃前後の温度まで加熱された材料と化学反応を起して劣化する。一方、本発明の蓄電デバイス１では、負極１２はバインダーを含まない状態で負極集電体１３表面に直接形成されているので、蒸着などの薄膜形成法を利用する機械的充電方法を適用でき、非常に有効である。 Also, when the negative electrode 12 is charged with a predetermined amount of electricity, the negative electrode 12 directly formed on the negative electrode current collector 13 without containing a binder in the electricity storage device 1 of the present invention is effective. The reason for this will be described below. For example, when lithium is deposited on the negative electrode 12 by vapor deposition and mechanical charging is performed, since the melting point of lithium is 179 ° C., the negative electrode 12 is exposed to lithium heated to a high temperature of at least about 179 ° C. Will be. At this time, when a lithium film is formed on the negative electrode containing the binder, most of the resin materials used as the main component of the binder are rich in chemical reactivity, such as lithium, and heated to a temperature of around 179 ° C. Deteriorates due to chemical reaction. On the other hand, in the electricity storage device 1 of the present invention, since the negative electrode 12 is formed directly on the surface of the negative electrode current collector 13 without containing a binder, a mechanical charging method using a thin film forming method such as vapor deposition can be applied, It is very effective.
　負極集電体１３としては、各種蓄電デバイスにおいて負極集電体に用いられるものを使用でき、その中でも、リチウムイオン電池の負極集電体に用いられるものを好ましく使用できる。このような負極集電体の具体例としては、たとえば、銅、ニッケルなどの金属からなる金属箔が挙げられる。これらの中でも、加工性などを考慮すると、銅箔が好ましい。負極集電板１３の形態としては、たとえば、表面が平滑なフィルム状、表面を粗面化したフィルム状、細い金属繊維からなるメッシュ状、多孔質フィルム状などが挙げられる。表面を粗面化したフィルム状の負極集電板１３を用いる場合、負極１２との密着性、蓄電デバイス１の出力特性などを考慮すると、負極集電板１３の表面粗さ（Ｒａ）は好ましくは１～２μｍ程度であり、また、好ましくは比表面積５以上、さらに好ましくは１０以上である。 As the negative electrode current collector 13, those used for the negative electrode current collector in various power storage devices can be used, and among them, those used for the negative electrode current collector of the lithium ion battery can be preferably used. Specific examples of such a negative electrode current collector include a metal foil made of a metal such as copper or nickel. Among these, copper foil is preferable in consideration of workability and the like. Examples of the form of the negative electrode current collector plate 13 include a film shape with a smooth surface, a film shape with a roughened surface, a mesh shape made of fine metal fibers, and a porous film shape. In the case of using a film-like negative electrode current collector plate 13 with a roughened surface, the surface roughness (Ra) of the negative electrode current collector plate 13 is preferable in consideration of adhesion to the negative electrode 12, output characteristics of the electricity storage device 1, and the like. Is about 1 to 2 μm, preferably 5 or more, more preferably 10 or more.
　層状の正極１０は、厚み方向の一方の面がセパレータ１４に接しかつ他方の面が正極集電体１１に接するように設けられ、正極活物質を含む。さらに正極１０は、正極活物質とともに、イオン伝導助材、電子伝導助材、バインダーなどを含んでもよい。
　正極活物質としては、充放電時において、少なくともアニオンを可逆的に吸脱着可能な材料を使用できる。たとえば、電気二重層キャパシタに用いられる正極活物質、電気化学キャパシタに用いられる正極活物質などが挙げられる。上記正極活物質に用いられる材料はカチオンを可逆的に吸脱着できてもよい。
　電気二重層キャパシタに用いられる正極活物質としては特に制限されないが、活性炭、酸化還元可能な有機化合物などを好ましく使用できる。活性炭としては、比表面積の高い活性炭が好ましい。たとえば、炭素材料（椰子殻、有機樹脂、石油ピッチなど）を、窒素ガスなどの不活性ガス中にて９００～１０００℃の温度下で炭化した後、この系内に水蒸気を導入することによって、最大２０００ｍ2／ｇ程度の極めて比表面積の高い活性炭が得られる。活性炭の形状は特に制限されず、たとえば、粉末状、繊維状、薄片状（または鱗片状）などの形状が挙げられる。 The layered positive electrode 10 is provided so that one surface in the thickness direction is in contact with the separator 14 and the other surface is in contact with the positive electrode current collector 11, and includes a positive electrode active material. Furthermore, the positive electrode 10 may contain an ion conduction aid, an electron conduction aid, a binder, and the like together with the positive electrode active material.
As the positive electrode active material, a material capable of reversibly adsorbing and desorbing at least anions during charge / discharge can be used. For example, the positive electrode active material used for an electric double layer capacitor, the positive electrode active material used for an electrochemical capacitor, etc. are mentioned. The material used for the positive electrode active material may be capable of reversibly adsorbing and desorbing cations.
Although it does not restrict | limit especially as a positive electrode active material used for an electrical double layer capacitor, Activated carbon, the organic compound which can be oxidized / reduced, etc. can be used preferably. As the activated carbon, activated carbon having a high specific surface area is preferable. For example, by carbonizing a carbon material (such as coconut shell, organic resin, petroleum pitch) in an inert gas such as nitrogen gas at a temperature of 900 to 1000 ° C., and then introducing water vapor into the system, Activated carbon having an extremely high specific surface area of up to about 2000 m 2 / g can be obtained. The shape of the activated carbon is not particularly limited, and examples thereof include a powder shape, a fiber shape, and a flake shape (or scale shape).
　酸化還元可能な有機化合物としては、たとえば、ラジカルを有する有機化合物、π電子共役雲を有する有機化合物、インドール系有機化合物などが挙げられる。ラジカルを有する有機化合物としては、たとえば、分子内にニトロキシラジカル、ホウ素ラジカルおよび酸素ラジカルから選ばれる少なくとも１種のラジカルを有する有機化合物が挙げられる。このような有機化合物の具体例としては、たとえば、２，２，６，６－テトラメチルピペリジン－１－オキシル、２，２，５，５－テトラメチル－３－イミダゾリウム－１－ロキシなどのニトロキシラジカル含有化合物、キノン、ベンゾキノンなどのキノン類などが挙げられる。π電子共役雲を有する有機化合物としては、たとえば、下記の一般式（１）で表される構造を有する有機化合物が挙げられる。 Examples of the organic compound capable of oxidation / reduction include organic compounds having radicals, organic compounds having π-electron conjugated clouds, and indole organic compounds. Examples of the organic compound having a radical include an organic compound having at least one radical selected from a nitroxy radical, a boron radical, and an oxygen radical in the molecule. Specific examples of such organic compounds include, for example, 2,2,6,6-tetramethylpiperidine-1-oxyl, 2,2,5,5-tetramethyl-3-imidazolium-1-loxy and the like Examples thereof include nitroxy radical-containing compounds, quinones such as quinone and benzoquinone. Examples of the organic compound having a π electron conjugated cloud include an organic compound having a structure represented by the following general formula (1).
Figure JPOXMLDOC01-appb-C000001
Figure JPOXMLDOC01-appb-C000001
　一般式（１）中、４つのＸはそれぞれ独立して硫黄原子または酸素原子を示す。Ｒ1～Ｒ4はそれぞれ独立して鎖状脂肪族基、環状脂肪族基、水素原子、ヒドロキシル基、シアノ基、アミノ基、ニトロ基またはニトロソ基を示す。Ｒ5およびＲ6はそれぞれ独立して水素原子、鎖状脂肪族基または環状脂肪族基を示す。但し、Ｒ1～Ｒ6で示される鎖状脂肪族基および環状脂肪族基は、酸素原子、窒素原子、硫黄原子、珪素原子、リン原子、ホウ素原子およびハロゲン原子からなる群より選ばれる少なくとも１種の原子を含んでもよい。
　下記の一般式（２）で表される構造を有する有機化合物が挙げられる。 In the general formula (1), four Xs each independently represent a sulfur atom or an oxygen atom. R 1 to R 4 each independently represents a chain aliphatic group, a cyclic aliphatic group, a hydrogen atom, a hydroxyl group, a cyano group, an amino group, a nitro group, or a nitroso group. R 5 and R 6 each independently represent a hydrogen atom, a chain aliphatic group or a cyclic aliphatic group. However, the chain aliphatic group and cycloaliphatic group represented by R 1 to R 6 are at least one selected from the group consisting of oxygen atom, nitrogen atom, sulfur atom, silicon atom, phosphorus atom, boron atom and halogen atom. It may contain seed atoms.
The organic compound which has a structure represented by following General formula (2) is mentioned.
Figure JPOXMLDOC01-appb-C000002
Figure JPOXMLDOC01-appb-C000002
　一般式（２）中におけるＲ1～Ｒ6は一般式（１）のＲ1～Ｒ6と同じである。
　下記の一般式（３）で表される構造を有する有機化合物が挙げられる。 R 1 ~ R 6 in the general formula (2) are the same as R 1 ~ R 6 in the general formula (1).
The organic compound which has a structure represented by following General formula (3) is mentioned.
Figure JPOXMLDOC01-appb-C000003
Figure JPOXMLDOC01-appb-C000003
　一般式（３）中、Ｘ1～Ｘ4はそれぞれ独立して硫黄原子、酸素原子、セレン原子またはテルル原子を示す。Ｒ7およびＲ8はそれぞれ独立して２価の鎖状脂肪族基または２価の環状脂肪族基を示す。但し、Ｒ7～Ｒ8で示される２価の鎖状脂肪族基および２価の環状脂肪族基は、酸素原子、窒素原子、硫黄原子、珪素原子、リン原子、ホウ素原子およびハロゲン原子からなる群より選ばれる少なくとも１種の原子を含んでもよい。 In the general formula (3), X 1 to X 4 each independently represent a sulfur atom, an oxygen atom, a selenium atom or a tellurium atom. R 7 and R 8 each independently represents a divalent chain aliphatic group or a divalent cyclic aliphatic group. However, the divalent chain aliphatic group and divalent cyclic aliphatic group represented by R 7 to R 8 are composed of an oxygen atom, a nitrogen atom, a sulfur atom, a silicon atom, a phosphorus atom, a boron atom, and a halogen atom. It may contain at least one atom selected from the group.
　なお、上記一般式（１）～（３）において、Ｒ1～Ｒ8で示される１価または２価の鎖状脂肪族基および環状脂肪族基は、その分子鎖中に、酸素原子、窒素原子、硫黄原子、リン原子などの原子を有していても良い。ここで、酸素原子、窒素原子、硫黄原子、シリコン原子などの原子を有していても良いとは、これらの原子の少なくとも１つを含む基を有していてもよいことを意味する。窒素原子を有する基としては、たとえば、アミノ基、イミノ基、シアノ基、ニトロ基などが挙げられる。酸素原子を有する基としては、たとえば、アルコキシ基、水酸基、水酸基を有するアルキル基、オキソ基などが挙げられる。硫黄原子を有する基としては、たとえば、スルホ基、スルホニル基、スルホン酸基、チオカルボニル基、スルファモイル基、アルキルスルホニル基などが挙げられる。シリコン原子を有する基としては、たとえば、シリル基などが挙げられる。また、アルキル基、アルケニル基などにおける飽和または不飽和の炭素鎖の途中にこれらの原子の少なくとも１種が組み込まれていてもよい。ホウ素原子およびハロゲン原子は各種置換基に結合できる。ホウ素原子およびハロゲン原子は、Ｒ1～Ｒ8で示される１価または２価の鎖状脂肪族基および環状脂肪族基に直接置換していても良い。 In the above general formulas (1) to (3), the monovalent or divalent chain aliphatic group and cyclic aliphatic group represented by R 1 to R 8 are oxygen atoms, nitrogen atoms in the molecular chain. You may have atoms, such as an atom, a sulfur atom, and a phosphorus atom. Here, “may have an atom such as an oxygen atom, a nitrogen atom, a sulfur atom, or a silicon atom” means that it may have a group containing at least one of these atoms. Examples of the group having a nitrogen atom include an amino group, an imino group, a cyano group, and a nitro group. Examples of the group having an oxygen atom include an alkoxy group, a hydroxyl group, an alkyl group having a hydroxyl group, and an oxo group. Examples of the group having a sulfur atom include a sulfo group, a sulfonyl group, a sulfonic acid group, a thiocarbonyl group, a sulfamoyl group, and an alkylsulfonyl group. Examples of the group having a silicon atom include a silyl group. Further, at least one of these atoms may be incorporated in the middle of a saturated or unsaturated carbon chain in an alkyl group, an alkenyl group or the like. Boron and halogen atoms can be bonded to various substituents. The boron atom and the halogen atom may be directly substituted with a monovalent or divalent chain aliphatic group or cyclic aliphatic group represented by R 1 to R 8 .
　インドール系有機化合物としては、たとえば、５－シアノインドールなどのインドール３量体、その誘導体などが挙げられる。
　また、電気化学キャパシタに用いられる正極活物質としては、電気二重層キャパシタに常用される正極活物質のほかに、酸化還元反応により発現する擬似二重層容量を有する材料をも含む。このような正極活物質の具体例としては、たとえば、酸化ルテニウム、酸化イリジウム、酸化マンガンなどの金属酸化物、ナノゲートカーボン、カーボンナノチューブなどのナノカーボン材料などが挙げられる。正極活物質は１種を単独でまたは必要に応じて２種以上を組み合わせて使用できる。 Examples of indole organic compounds include indole trimers such as 5-cyanoindole, and derivatives thereof.
Moreover, as a positive electrode active material used for an electrochemical capacitor, the material which has the pseudo | simulation double layer capacity | capacitance which expresses by oxidation-reduction reaction other than the positive electrode active material normally used for an electric double layer capacitor is also included. Specific examples of such a positive electrode active material include metal oxides such as ruthenium oxide, iridium oxide, and manganese oxide, and nanocarbon materials such as nanogate carbon and carbon nanotubes. A positive electrode active material can be used individually by 1 type or in combination of 2 or more types as needed.
　イオン伝導助材は、たとえば、イオン伝導性を改善するために用いられる。イオン伝導助材の具体例としては、たとえば、ポリエチレンオキシドなどの固体電解質、ポリメタクリル酸メチルなどを含むゲル電解質などが挙げられる。
　電子伝導助材は、たとえば、電子伝導性を改善するために用いられる。電子伝導助材の具体例としては、たとえば、カーボンブラック、グラファイト、アセチレンブラックなどの炭素材料、ポリアニリン、ポリピロール、ポリチオフェンなどの導電性高分子などが挙げられる。
　バインダーは、たとえば、正極活物質の結着性を改善するために用いられる。バインダーとしては、たとえば、ポリフッ化ビニリデン、フッ化ビニリデン－ヘキサフルオロプロピレン共重合体、フッ化ビニリデン－ポリテトラフルオロエチレン、ポリテトラフルオロエチレン、ポリエチレン、ポリイミド、ポリアクリル酸、カルボキシメチルセルロース、アクリロニトリルゴム、ブタジエンゴム、スチレンブタジエンゴムなどが挙げられる。 The ion conduction aid is used for improving ion conductivity, for example. Specific examples of the ion conduction aid include, for example, a solid electrolyte such as polyethylene oxide, a gel electrolyte containing polymethyl methacrylate, and the like.
The electron conduction aid is used, for example, to improve electron conductivity. Specific examples of the electron conduction aid include carbon materials such as carbon black, graphite, and acetylene black, and conductive polymers such as polyaniline, polypyrrole, and polythiophene.
The binder is used, for example, to improve the binding property of the positive electrode active material. Examples of the binder include polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-polytetrafluoroethylene, polytetrafluoroethylene, polyethylene, polyimide, polyacrylic acid, carboxymethylcellulose, acrylonitrile rubber, and butadiene. Examples thereof include rubber and styrene butadiene rubber.
　正極１０の厚み（以下、「正極厚み」とする）は特に制限されないが、たとえば、電解質保持性などを考慮すると、好ましくは負極１２の厚み（以下、「負極厚み」とする）の５倍以上、さらに好ましくは負極厚みの１０倍以上である。なお、正極厚みの負極厚みに対する上限は、５０～１００倍程度である。負極厚みに対して、正極厚みが５０～１００倍程度と厚すぎる場合、蓄電デバイスの蓄電容量が負極規制になってしまい、容量低下が起こってしまうためである。本発明の蓄電デバイス１においては、上記したように、負極集電体１３の表面に負極１２を直接形成することによって、負極厚みを薄くする。したがって、負極１２内部での電解質保持性が低下するおそれがある。それを補うために、正極厚みを大きくするのが好ましい。
　具体的には、負極厚みが２～１０μｍ程度、正極厚みがその１０倍以上となる２０～１００μｍ程度が望ましい。さらに好ましくは、負極厚みは２～５μｍ、正極厚みがその１０倍以上となる２０～５０μｍ程度が望ましい。 The thickness of the positive electrode 10 (hereinafter referred to as “positive electrode thickness”) is not particularly limited, but for example, in view of electrolyte retention, it is preferably at least 5 times the thickness of the negative electrode 12 (hereinafter referred to as “negative electrode thickness”). More preferably, it is 10 times or more the thickness of the negative electrode. The upper limit of the positive electrode thickness to the negative electrode thickness is about 50 to 100 times. This is because, if the thickness of the positive electrode is too thick, such as about 50 to 100 times the thickness of the negative electrode, the storage capacity of the electricity storage device becomes negative electrode regulation, resulting in a decrease in capacity. In the electricity storage device 1 of the present invention, as described above, the negative electrode 12 is directly formed on the surface of the negative electrode current collector 13 to reduce the thickness of the negative electrode. Therefore, there is a possibility that the electrolyte retention in the negative electrode 12 may be reduced. In order to compensate for this, it is preferable to increase the thickness of the positive electrode.
Specifically, it is desirable that the thickness of the negative electrode is about 2 to 10 μm and the thickness of the positive electrode is about 20 to 100 μm, which is 10 times or more. More preferably, the thickness of the negative electrode is 2 to 5 μm, and the thickness of the positive electrode is preferably about 20 to 50 μm, which is 10 times or more.
　層状の正極集電体１１は、厚み方向の一方の面が正極１０に接し、かつ他方の面がケース１８に接するように設けられる。正極集電体１１としては、リチウムイオン電池の正極集電板に用いられる一般的な材料を使用でき、たとえば、アルミニウム、ステンレス鋼などが挙げられる。正極集電体１１は、好ましくは、フィルム状またはシート状に形成される。また、正極集電体１１の表面形態は平滑でも粗面化されていてもよい。正極集電体１１の内部構造は、金属繊維を含むメッシュ体、多孔質体などでもよい。 The layered positive electrode current collector 11 is provided so that one surface in the thickness direction is in contact with the positive electrode 10 and the other surface is in contact with the case 18. As the positive electrode current collector 11, a general material used for a positive electrode current collector plate of a lithium ion battery can be used, and examples thereof include aluminum and stainless steel. The positive electrode current collector 11 is preferably formed in a film shape or a sheet shape. Further, the surface form of the positive electrode current collector 11 may be smooth or roughened. The internal structure of the positive electrode current collector 11 may be a mesh body containing a metal fiber, a porous body, or the like.
　セパレータ１４は、正極１０と負極１２とにより挟持されるように設けられる。セパレータ１４には、リチウムイオン電池、電気二重層キャパシタなどに用いられるセパレータを使用でき、たとえば、ポリプロピレン、ポリエチレンなどの微多孔膜、不織布などが挙げられる。
　セパレータ１４には、必要に応じて、電解質が担持されるかまたは含浸される。電解質としては特に制限されないが、たとえば、支持塩（電解質塩）、支持塩を非水溶媒に溶解した液状電解質（または非水電解液）、ゲル電解質、固体電解質などが挙げられる。 The separator 14 is provided so as to be sandwiched between the positive electrode 10 and the negative electrode 12. The separator 14 can be a separator used for lithium ion batteries, electric double layer capacitors, and the like, and examples thereof include microporous films such as polypropylene and polyethylene, and nonwoven fabrics.
The separator 14 is supported or impregnated with an electrolyte as required. The electrolyte is not particularly limited, and examples thereof include a supporting salt (electrolyte salt), a liquid electrolyte (or nonaqueous electrolytic solution) obtained by dissolving the supporting salt in a nonaqueous solvent, a gel electrolyte, and a solid electrolyte.
　支持塩は、蓄電デバイス１の種類に応じて、公知の支持塩の中から適宜選択して使用できる。たとえば、蓄電デバイス１をリチウムイオン電池として用いる場合には、リチウムとアニオンとを含む塩を使用できる。アニオンとしてはリチウムと塩を形成するものであれば特に制限されないが、たとえば、ハロゲン化物アニオン、過塩素酸アニオン、トリフルオロメタンスルホン酸アニオン、４フッ化ホウ酸アニオン（ＢＦ4 -）、６フッ化リン酸アニオン（ＰＦ6 -）、ビス（トリフルオロメタンスルホニル）イミドアニオン、ビス（パーフルオロエチルスルホニル）イミドアニオンなどが挙げられる。支持塩は１種を単独で使用できまたは必要に応じて２種以上を組み合わせて用いてもよい。 The supporting salt can be appropriately selected from known supporting salts according to the type of the electricity storage device 1 and used. For example, when the electricity storage device 1 is used as a lithium ion battery, a salt containing lithium and an anion can be used. The anion is not particularly limited as long as it forms a salt with lithium. For example, halide anion, perchlorate anion, trifluoromethanesulfonate anion, tetrafluoroborate anion (BF 4 − ), hexafluoride Examples thereof include phosphate anion (PF 6 − ), bis (trifluoromethanesulfonyl) imide anion, and bis (perfluoroethylsulfonyl) imide anion. A supporting salt can be used individually by 1 type, or may be used in combination of 2 or more types as needed.
　支持塩を溶解させる非水溶媒も、蓄電デバイス１の種類に応じて、公知の非水溶媒の中から適宜選択して使用できる。たとえば、蓄電デバイス１がリチウムイオン電池、非水系電気二重層キャパシタなどである場合は、非水溶媒としては、たとえば、エチレンカーボネート、プロピレンカーボネート、ジメチルカーボネート、ジエチルカーボネート、メチルエチルカーボネート、γ－ブチロラクトン、テトラヒドロフラン、ジオキソラン、スルホラン、ジメチルホルムアミド、アセトニトリルなどを使用できる。非水溶媒は１種を単独で用いてもよくまたは２種以上を組み合わせて用いてもよい。 The non-aqueous solvent in which the supporting salt is dissolved can be appropriately selected from known non-aqueous solvents according to the type of the electricity storage device 1 and used. For example, when the electricity storage device 1 is a lithium ion battery, a non-aqueous electric double layer capacitor or the like, examples of the non-aqueous solvent include ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, γ-butyrolactone, Tetrahydrofuran, dioxolane, sulfolane, dimethylformamide, acetonitrile and the like can be used. A non-aqueous solvent may be used individually by 1 type, or may be used in combination of 2 or more type.
　ゲル電解質は、液状電解質をゲル化したものである。液状電解質のゲル化は、たとえば、液状電解質にゲル化剤を添加することにより行われる。ゲル化剤としてはこの分野で常用されるものを使用でき、たえとば、ポリアクリロニトリル、アクリレート化合物またはメタクリレート化合物をモノマー成分として含む重合体、エチレンとアクリロニトリルとの共重合体などが挙げられる。固体電解質は、固形状の電解質である。固体電解質としては、たとえば、Ｌｉ2Ｓ－ＳｉＳ2、Ｌｉ2Ｓ－Ｂ2Ｓ5、Ｌｉ2Ｓ－Ｐ2Ｓ5－ＧｅＳ2、ナトリウムとアルミナ（Ａｌ2Ｏ3）との混合物、無定形ポリエーテル、相転移温度（Ｔｇ）の低いポリエーテル、無定形フッ化ビニリデン－６フッ化プロピレンコポリマー、異種高分子ブレンド体ポリエチレンオキサイドなどが挙げられる。ゲル電解質および固体電解質を用いる場合、セパレータ１４を用いずに、正極１０と負極１２との間に電解質のみを配して蓄電デバイス１を構成してもよい。 The gel electrolyte is a gelled liquid electrolyte. The gelation of the liquid electrolyte is performed, for example, by adding a gelling agent to the liquid electrolyte. As the gelling agent, those commonly used in this field can be used, and examples thereof include a polymer containing polyacrylonitrile, an acrylate compound or a methacrylate compound as a monomer component, and a copolymer of ethylene and acrylonitrile. The solid electrolyte is a solid electrolyte. Examples of the solid electrolyte include Li 2 S—SiS 2 , Li 2 S—B 2 S 5 , Li 2 S—P 2 S 5 —GeS 2 , a mixture of sodium and alumina (Al 2 O 3 ), and amorphous. Examples include polyethers, polyethers having a low phase transition temperature (Tg), amorphous vinylidene fluoride-6-propylene copolymer, and heterogeneous polymer blend polyethylene oxide. When the gel electrolyte and the solid electrolyte are used, the electricity storage device 1 may be configured by arranging only the electrolyte between the positive electrode 10 and the negative electrode 12 without using the separator 14.
　封口板１５、ガスケット１６、スペーサー１７およびケース１８としては、この分野で常用されるものをいずれも使用できる。
　蓄電デバイス１は、たとえば、スペーサー１７、負極集電体１３、負極１２、セパレータ１４、正極１０および正極集電体１１をこの順番で厚み方向に積層し、得られる積層体を封口板１５とケース１８とによって挟持し、封口板１５とケース１８とをガスケット１６を介してかしめることによって製造できる。なお、蓄電デバイス１における負極集電体１３、負極１２、セパレータ１４、正極１０、正極集電体１１などの各部材の接触圧が十分である場合には、スペーサー１７を設ける必要はない。すなわち、スペーサー１７を設けるか否かは、前記各部材の接触圧などに応じて、適宜選択すればよい。 As the sealing plate 15, the gasket 16, the spacer 17, and the case 18, any of those commonly used in this field can be used.
For example, the power storage device 1 includes a spacer 17, a negative electrode current collector 13, a negative electrode 12, a separator 14, a positive electrode 10, and a positive electrode current collector 11 that are stacked in this order in the thickness direction. 18, and the sealing plate 15 and the case 18 are caulked through the gasket 16. In addition, when the contact pressure of each member such as the negative electrode current collector 13, the negative electrode 12, the separator 14, the positive electrode 10, and the positive electrode current collector 11 in the electricity storage device 1 is sufficient, the spacer 17 is not necessary. That is, whether or not to provide the spacer 17 may be appropriately selected according to the contact pressure of each member.
　本発明の蓄電デバイスは、たとえば、ハイブリッド自動車、各種電気・電子機器（特に移動体通信機器や、ノートＰＣや携帯電話などの携帯電子機器）などの電源、火力発電、風力発電、燃料電池発電などの発電平準化用の蓄電デバイス、一般家庭および集合住宅用の非常用蓄電システム、深夜電力蓄電システムなどの電源、無停電電源などとして好適に使用できる。
　以下に、本発明の実施の形態として蓄電デバイスの携帯電話等への使用例を示す。 The power storage device of the present invention includes, for example, a power source such as a hybrid vehicle, various electric / electronic devices (particularly mobile communication devices, portable electronic devices such as notebook PCs and mobile phones), thermal power generation, wind power generation, fuel cell power generation, etc. It can be suitably used as a power storage device for power generation leveling, an emergency power storage system for ordinary homes and apartment buildings, a power source for a midnight power storage system, an uninterruptible power supply, and the like.
Hereinafter, as an embodiment of the present invention, an example of using an electricity storage device for a mobile phone or the like will be described.
実施の形態１
　本発明の蓄電デバイスを用いた携帯電話の一例を、図１０を参照しながら説明する。図１０は、本発明の蓄電デバイスを電源に用いた携帯電話１００の概略斜視図である。図１０に示すように、携帯電話１００は、液晶パネル等の表示部１６６および入力部１６８を有し、入力部１６８が設けられた筐体１６０内に、電子制御回路部（図示しない）、および電源部として本発明の蓄電デバイス１５０が設置されている。制御回路部は、たとえば蓄電デバイスの充電量（ＳＯＣ）やパネルの表示を制御する。また、たとえば蓄電デバイスの充電時の電圧を制御する。
　蓄電デバイス１５０として、本発明の蓄電デバイスと、従来の蓄電デバイスとを組み合わせて用いてもよい。従来の蓄電デバイスとは、例えば、リチウムイオン電池、ニッケル水素蓄電池、キャパシタ、または燃料電池が挙げられる。
　本発明の蓄電デバイスは小型・薄型化が可能であるため、蓄電デバイスの設置に要するスペースを小さくでき、携帯電話を小型・薄型化できる。本発明の蓄電デバイスは高速充電が可能であるため、充電時間を短縮できる。本発明の蓄電デバイスは高出力および高容量を有するため、携帯電話の連続通話時間の延長等の高性能化が可能である。 Embodiment 1
An example of a cellular phone using the electricity storage device of the present invention will be described with reference to FIG. FIG. 10 is a schematic perspective view of a mobile phone 100 using the power storage device of the present invention as a power source. As shown in FIG. 10, the mobile phone 100 includes a display unit 166 such as a liquid crystal panel and an input unit 168, and an electronic control circuit unit (not shown) and a housing 160 provided with the input unit 168, and The power storage device 150 of the present invention is installed as a power supply unit. The control circuit unit controls, for example, the charge amount (SOC) of the power storage device and the display on the panel. For example, the voltage at the time of charge of an electrical storage device is controlled.
As the power storage device 150, the power storage device of the present invention and a conventional power storage device may be used in combination. Examples of conventional power storage devices include lithium ion batteries, nickel metal hydride storage batteries, capacitors, and fuel cells.
Since the electricity storage device of the present invention can be reduced in size and thickness, the space required for installing the electricity storage device can be reduced, and the mobile phone can be reduced in size and thickness. Since the electricity storage device of the present invention can be charged at high speed, the charging time can be shortened. Since the electricity storage device of the present invention has a high output and a high capacity, it is possible to improve the performance such as extending the continuous talk time of the mobile phone.
実施の形態２
　本発明の蓄電デバイスを用いたノートＰＣの一例を、図１１を参照しながら説明する。図１１は、本発明の蓄電デバイスを電源に用いたノートＰＣ２００の概略斜視図である。図１１に示すように、ノートＰＣ２００は、液晶パネル等の表示部２６６およびキー操作部２１０を備えた筐体２６０を備え、筐体２６０内にＣＰＵ等を備えた電子制御回路部（図示しない）、冷却用ファン（図示しない）、および電源部として本発明の蓄電デバイス２７０が設置されている。
　蓄電デバイス２７０として、本発明の蓄電デバイスと、従来の蓄電デバイスとを組み合わせて用いてもよい。従来の蓄電デバイスとは、例えば、リチウムイオン電池、ニッケル水素蓄電池、キャパシタ、または燃料電池が挙げられる。
　本発明の蓄電デバイスは小型・薄型化が可能であるため、蓄電デバイスの設置に要するスペースを小さくでき、ノートＰＣの小型・薄型化が可能である。本発明の蓄電デバイスは高速充電が可能であるため、充電時間を短縮できる。本発明の蓄電デバイスは高出力および高容量を有するため、ノートＰＣの長時間の使用、または高速起動などが可能となる。 Embodiment 2
An example of a notebook PC using the electricity storage device of the present invention will be described with reference to FIG. FIG. 11 is a schematic perspective view of a notebook PC 200 using the power storage device of the present invention as a power source. As shown in FIG. 11, the notebook PC 200 includes a housing 260 including a display unit 266 such as a liquid crystal panel and a key operation unit 210, and an electronic control circuit unit (not shown) including a CPU and the like in the housing 260. A power storage device 270 of the present invention is installed as a cooling fan (not shown) and a power supply unit.
As the power storage device 270, the power storage device of the present invention and a conventional power storage device may be used in combination. Examples of conventional power storage devices include lithium ion batteries, nickel metal hydride storage batteries, capacitors, and fuel cells.
Since the electricity storage device of the present invention can be reduced in size and thickness, the space required for installing the electricity storage device can be reduced, and the notebook PC can be reduced in size and thickness. Since the electricity storage device of the present invention can be charged at high speed, the charging time can be shortened. Since the electricity storage device of the present invention has a high output and a high capacity, the notebook PC can be used for a long time or can be started at a high speed.
実施の形態３
　本発明の蓄電デバイスを用いたハイブリッド自動車の一例を、図１２を参照しながら説明する。図１２は、本発明の蓄電デバイスを用いたハイブリッド自動車３００の構成を示す図である。図１２に示すように、ハイブリッド自動車３００は、エンジン３０２と、複数のモーター３０３、３０４、および３０５と、これらにそれぞれ接続するインバーター３０６、３０７、および３０８と、電力を供給する電源部として本発明の蓄電デバイス３０９と、システム全体を制御するコントローラー３１０からなる。モーター３０３は、エンジン３０２の始動用または発車のアシスト用のモーターであり、発電機としても機能する。モーター３０４は車駆動用のモーターであり、モーター３０５は操舵（パワーステアリング）用のモーターである。蓄電デバイス３０９の放電（電力供給）により、モーター３０３が駆動してエンジン３０２を始動または発進をアシストし、油圧装置３１１に接続されたモーター３０５が高速駆動する。蓄電デバイス３０９の充電は、モーター３０３を発電機として用い、エンジン３０２の駆動力を電力に変換して行われる。
　蓄電デバイス３０９として、本発明の蓄電デバイスと、従来の蓄電デバイスとを組み合わせて用いてもよい。従来の蓄電デバイスとは、例えば、リチウムイオン電池、ニッケル水素蓄電池、キャパシタ、または燃料電池が挙げられる。
　本発明の蓄電デバイスは小型・薄型化が可能であるため、自動車の軽量化が可能となる。また、蓄電デバイスの設置に要するスペースを小さくでき、収納スペースや座席スペースをより大きく確保することが可能となる。本発明の蓄電デバイスは、高速充放電でき、高出力および高容量を有するため、種々の走行モードに対応でき、自動車の燃費向上に寄与することができる。 Embodiment 3
An example of a hybrid vehicle using the electricity storage device of the present invention will be described with reference to FIG. FIG. 12 is a diagram showing a configuration of a hybrid vehicle 300 using the electricity storage device of the present invention. As shown in FIG. 12, the hybrid vehicle 300 includes the engine 302, a plurality of motors 303, 304, and 305, inverters 306, 307, and 308 connected to the motor 302, and a power supply unit that supplies power. Power storage device 309 and a controller 310 for controlling the entire system. The motor 303 is a motor for starting the engine 302 or assisting departure of the vehicle, and also functions as a generator. The motor 304 is a motor for driving a vehicle, and the motor 305 is a motor for steering (power steering). Due to the discharge (power supply) of the electricity storage device 309, the motor 303 is driven to assist in starting or starting the engine 302, and the motor 305 connected to the hydraulic device 311 is driven at high speed. The power storage device 309 is charged by converting the driving force of the engine 302 into electric power using the motor 303 as a generator.
As the power storage device 309, the power storage device of the present invention and a conventional power storage device may be used in combination. Examples of conventional power storage devices include lithium ion batteries, nickel metal hydride storage batteries, capacitors, and fuel cells.
Since the electricity storage device of the present invention can be reduced in size and thickness, the weight of an automobile can be reduced. In addition, the space required for installing the power storage device can be reduced, and a larger storage space and seat space can be secured. Since the electricity storage device of the present invention can be charged and discharged at high speed and has high output and high capacity, it can cope with various driving modes and contribute to improvement in fuel efficiency of an automobile.
　以下、本発明の実施例を詳細に説明するが、本発明はこれらの実施例に限定されない。
《実施例１》
　図１に示すのと同様のコイン型蓄電デバイスを、以下の手順で作製した。
（１）正極の作製
　正極活物質としての活性炭粉末（比表面積１７００ｍ2／ｇ、数平均粒子径２μｍ）１００ｍｇと、電子伝導助材としてのアセチレンブラック２０ｍｇとを均一に混合した。この混合物にポリビニルピロリドン２０ｍｇおよびメタノール８００ｍｇを加えて正極合剤スラリーを調製した。この正極合剤スラリーをアルミニウム箔からなる正極集電体（厚み１５μｍ）上に塗布した後、真空乾燥し、アルミニウム箔表面に層状の正極を形成した。この正極集電体と正極とからなる正極積層体を直径１３．５ｍｍの円盤状に打ち抜き裁断した。このとき、正極活物質の塗布重量は６．１ｍｇ／ｃｍ２、正極厚みは４５μｍであった。なお、正極活物質である活性炭粉末は、フェノール樹脂系炭素材料を窒素ガス中で炭化させた後、水蒸気を導入して賦活処理を施すことによって得られたものである。
　また、この正極積層体を用い、かつ全く同じ構成の積層体を対極（負極）として用いて得られる電気二重層キャパシタを、単極電位０～１Ｖ（蓄電デバイスとしては０～２Ｖ）の範囲で動作（充放電）させた場合、その蓄電デバイス容量は０．０８ｍＡｈであった。 Examples of the present invention will be described in detail below, but the present invention is not limited to these examples.
Example 1
A coin-type electricity storage device similar to that shown in FIG. 1 was produced by the following procedure.
(1) Production of positive electrode 100 mg of activated carbon powder (specific surface area 1700 m 2 / g, number average particle diameter 2 μm) as a positive electrode active material and 20 mg of acetylene black as an electron conduction aid were uniformly mixed. A positive electrode mixture slurry was prepared by adding 20 mg of polyvinylpyrrolidone and 800 mg of methanol to this mixture. The positive electrode mixture slurry was applied on a positive electrode current collector (thickness 15 μm) made of an aluminum foil, and then vacuum-dried to form a layered positive electrode on the surface of the aluminum foil. The positive electrode laminate comprising the positive electrode current collector and the positive electrode was punched and cut into a disk shape having a diameter of 13.5 mm. At this time, the coating weight of the positive electrode active material was 6.1 mg / cm 2 , and the positive electrode thickness was 45 μm. In addition, the activated carbon powder which is a positive electrode active material is obtained by carbonizing a phenol resin-based carbon material in nitrogen gas, and then performing activation treatment by introducing water vapor.
In addition, an electric double layer capacitor obtained by using this positive electrode laminate and using a laminate having exactly the same structure as a counter electrode (negative electrode) can be used in a range of a single electrode potential of 0 to 1 V (0 to 2 V as an electric storage device). When operated (charge / discharge), the electricity storage device capacity was 0.08 mAh.
（２）負極の作製
　負極集電体に銅箔（比表面積１１．６、算術平均表面粗さ（Ｒａ）２．０μｍ、厚み４３μｍ）を用いた。電子線加熱蒸着法により、この銅箔上に珪素酸化物（ＳｉＯｘ）の薄膜からなる負極（厚み６μｍ、比表面積４．２）を形成した。比表面積および算術平均表面粗さは、レーザー顕微鏡（商品名：超深度形状測定顕微鏡ＶＫ－８５５、キーエンス社製）を用いて測定した。負極集電体および負極の厚みは走査型電子顕微鏡（ＳＥＭ）により測定した。負極集電体の電解質保持部の容積比率は、後述の実施例１０と同様の方法により求めた。
　このようにして、負極集電体と負極とからなる負極積層体を得た。負極厚みの調整は蒸着時間を調整して行った。電子線加熱蒸着の条件は次の通りである。蒸着源として、純度９９．９９９９％の珪素金属（（株）高純度化学研究所製）を用い、真空チャンバー内に純度９９．７％の酸素ガス（日本酸素（株）製）を導入して真空度３×１０－３Ｐａに調整した。また、蒸着源に照射する電子ビームの加速電圧を８ｋＶ、エミッションを５００ｍＡとした。負極形成後、蛍光Ｘ線分析により組成を分析した結果、負極中のＳｉとＯとの比はＳｉ：Ｏ＝１：０．６（モル比）であった。このことから、負極を構成する酸化珪素（ＳｉＯｘ）のｘの値は０．６であることが判った。 (2) Production of Negative Electrode A copper foil (specific surface area 11.6, arithmetic average surface roughness (Ra) 2.0 μm, thickness 43 μm) was used for the negative electrode current collector. A negative electrode (thickness 6 μm, specific surface area 4.2) made of a thin film of silicon oxide (SiOx) was formed on the copper foil by electron beam heating vapor deposition. The specific surface area and arithmetic average surface roughness were measured using a laser microscope (trade name: Ultradeep shape measuring microscope VK-855, manufactured by Keyence Corporation). The thickness of the negative electrode current collector and the negative electrode was measured with a scanning electron microscope (SEM). The volume ratio of the electrolyte holding part of the negative electrode current collector was determined by the same method as in Example 10 described later.
Thus, the negative electrode laminated body which consists of a negative electrode collector and a negative electrode was obtained. The negative electrode thickness was adjusted by adjusting the deposition time. The conditions for electron beam heating vapor deposition are as follows. As a deposition source, silicon metal with a purity of 99.9999% (manufactured by Kojundo Chemical Laboratory Co., Ltd.) was used, and oxygen gas with a purity of 99.7% (manufactured by Nippon Oxygen Co., Ltd.) was introduced into the vacuum chamber. The degree of vacuum was adjusted to 3 × 10 −3 Pa. In addition, the acceleration voltage of the electron beam irradiated to the vapor deposition source was 8 kV, and the emission was 500 mA. As a result of analyzing the composition by fluorescent X-ray analysis after forming the negative electrode, the ratio of Si and O in the negative electrode was Si: O = 1: 0.6 (molar ratio). From this, it was found that the value of x of silicon oxide (SiOx) constituting the negative electrode was 0.6.
　次に、上記で得られた負極の容量を、以下のようにして確認した。上記と同じ方法で作製した負極積層体を、直径１３．５ｍｍの円盤状に打ち抜き裁断したものと、リチウム金属板（厚み３００μｍ）からなる対極とを、多孔質ポリエチレンシートからなるセパレータ（厚み２０μｍ）を介して対向配置してコイン型蓄電デバイスを作製した。この蓄電デバイスを３回充放電した。このとき、電流値０．５ｍＡ、上限電圧１．５Ｖ、および下限電圧０Ｖとした。この充放電により、充放電可能な可逆容量は１．８ｍＡｈ（単位面積あたりの容量：１．３ｍＡｈ/ｃｍ２）であり、充放電に寄与しない不可逆容量は０．５ｍＡｈであることを確認した。 Next, the capacity of the negative electrode obtained above was confirmed as follows. A separator (thickness 20 μm) made of a porous polyethylene sheet is formed by punching and cutting a negative electrode laminate produced by the same method as above into a disc shape having a diameter of 13.5 mm and a counter electrode made of a lithium metal plate (thickness 300 μm). A coin-type electricity storage device was manufactured by facing each other. This electricity storage device was charged and discharged three times. At this time, the current value was 0.5 mA, the upper limit voltage was 1.5 V, and the lower limit voltage was 0 V. By this charging / discharging, it was confirmed that the reversible capacity capable of charging / discharging was 1.8 mAh (capacity per unit area: 1.3 mAh / cm 2 ), and the irreversible capacity not contributing to charging / discharging was 0.5 mAh.
　上記で得られた作製直後の負極はリチウムを含まないため、完全放電状態、すなわちＳＯＣ（State of Charge）０％の状態である。負極のＳＯＣとは、蓄電デバイス全体としてではなく、負極単体の充電状態を表す指標であり、負極単体の満充電時の容量を１００％として、満充電量に対する充電量の割合を百分率で表した値である。したがって、完全に放電された状態のＳＯＣは０％であり、満充電状態のＳＯＣは１００％である。
　本実施例では、上記で得られた負極表面に厚み４．５μｍのリチウム金属層を蒸着法により形成して負極のＳＯＣを５０％に調整した。ここでは、リチウム基準で０～１．５Ｖの電位範囲において、負極容量に対して０．２ＣＡ（５時間率）で充電させた場合の負極の充電量をＳＯＣ１００％（満充電）とし、この値を基準として負極のＳＯＣを求めた。なお、負極の表面に蒸着されたリチウム金属は、負極を電解質に浸漬しなくても負極に吸収され、負極が充電（リチウム充電）される。また、このリチウム充電量は、負極の不可逆容量に加えて、可逆容量の５０％（ＳＯＣ５０％）まで充電される充電電気量に相当する量である。ＳＯＣ５０％の負極は、厚みが９μｍであった。ＳＯＣ調整後、負極積層体を直径１３．５ｍｍの円盤状に打ち抜き裁断した。 Since the negative electrode immediately after fabrication obtained above does not contain lithium, it is in a completely discharged state, that is, in a state of SOC (State of Charge) 0%. The SOC of the negative electrode is an index that represents the state of charge of the single negative electrode, not the entire power storage device, and represents the percentage of the charge amount with respect to the full charge amount as a percentage with the capacity when the negative electrode is fully charged being 100%. Value. Therefore, the fully discharged SOC is 0%, and the fully charged SOC is 100%.
In this example, a 4.5 μm-thick lithium metal layer was formed on the negative electrode surface obtained above by an evaporation method, and the SOC of the negative electrode was adjusted to 50%. Here, the charge amount of the negative electrode when charged at 0.2 CA (5-hour rate) with respect to the negative electrode capacity in a potential range of 0 to 1.5 V with respect to lithium is defined as SOC 100% (full charge). The SOC of the negative electrode was determined based on the above. The lithium metal deposited on the surface of the negative electrode is absorbed by the negative electrode without being immersed in the electrolyte, and the negative electrode is charged (lithium charging). In addition to the irreversible capacity of the negative electrode, the lithium charge amount is an amount corresponding to the amount of charge charged to 50% of the reversible capacity (SOC 50%). The negative electrode with 50% SOC had a thickness of 9 μm. After the SOC adjustment, the negative electrode laminate was punched and cut into a disk shape having a diameter of 13.5 mm.
（３）蓄電デバイスの組み立て
　電解質を含浸させた多孔質ポリエチレンシートであるセパレータ（厚み２０μｍ）を介して、上記で得られた正極積層体と負極積層体とを対向配置し、電極体を作製した。電解質には、エチレンカーボネートとエチルメチルカーボネートとの混合溶媒（体積比１：３）に１．２５ｍｏｌ／Ｌの割合で６フッ化リン酸リチウム（支持塩または電解質塩）を溶解させた非水電解液を用いた。この電極体を、正極集電体側を下側にしてケースに収容した。プレス機により、ケースの開口端部と封口板の周縁部とをガスケットを介してかしめて、ケースを封口し、図１に示す本発明のコイン型蓄電デバイスを作製した。なお、正極の厚みに応じて、蓄電デバイス内の各部材の接触圧が不十分な場合には、適切な厚みを有するスペーサーを負極集電体と封口板との間に設けた。 (3) Assembling the electricity storage device The positive electrode laminate and the negative electrode laminate obtained above were arranged to face each other through a separator (thickness 20 μm), which is a porous polyethylene sheet impregnated with an electrolyte, to produce an electrode body. . In the electrolyte, nonaqueous electrolysis in which lithium hexafluorophosphate (supporting salt or electrolyte salt) is dissolved in a mixed solvent of ethylene carbonate and ethyl methyl carbonate (volume ratio 1: 3) at a rate of 1.25 mol / L. The liquid was used. The electrode body was housed in a case with the positive electrode current collector side facing down. The coin-type electricity storage device of the present invention shown in FIG. 1 was manufactured by caulking the opening end of the case and the peripheral edge of the sealing plate with a press to seal the case. Note that when the contact pressure of each member in the electricity storage device was insufficient according to the thickness of the positive electrode, a spacer having an appropriate thickness was provided between the negative electrode current collector and the sealing plate.
《実施例２》
　負極集電体に電解銅箔（比表面積１１．６、算術平均表面粗さ（Ｒａ）１．８μｍ、厚み４３μｍ）を用いた。ＲＦスパッタリングにより、この銅箔上に珪素の薄膜からなる負極（厚み１．５μｍ、比表面積１１．４）を形成した。このようにして、負極集電体と負極とからなる負極積層体を得た。
　ＲＦスパッタリングは以下のようにして行った。直径１０インチの溶融シリコンターゲット（ケイ素純度９９．９９％）を用い、ターゲットと基板との間の距離を７ｃｍとし、アルゴン５０ｓｃｃｍを導入した。真空雰囲気圧力１．１Ｐａ、印加電力１ｋＷ、および成膜時間５時間とした。 Example 2
An electrolytic copper foil (specific surface area 11.6, arithmetic average surface roughness (Ra) 1.8 μm, thickness 43 μm) was used for the negative electrode current collector. A negative electrode (thickness 1.5 μm, specific surface area 11.4) made of a silicon thin film was formed on the copper foil by RF sputtering. Thus, the negative electrode laminated body which consists of a negative electrode collector and a negative electrode was obtained.
RF sputtering was performed as follows. A 10-inch diameter molten silicon target (silicon purity 99.99%) was used, the distance between the target and the substrate was 7 cm, and argon 50 sccm was introduced. The vacuum atmosphere pressure was 1.1 Pa, the applied power was 1 kW, and the film formation time was 5 hours.
　実施例１と同様の方法により負極容量を確認した結果、充放電が可能な可逆容量が２．１ｍＡｈ（単位面積あたりの容量：１．５ｍＡｈ/ｃｍ２）であり、充放電に寄与しない不可逆容量が０．１ｍＡｈであった。
　本実施例では、上記で得られた負極表面に厚み４μｍのリチウム金属層を蒸着法により形成して負極のＳＯＣを５０％に調整した。なお、負極の表面に蒸着されたリチウム金属は、負極を電解質に浸漬しなくても負極に吸収され、負極が充電（リチウム充電）される。また、このリチウム充電量は、負極の不可逆容量に加えて、ＳＯＣ５０％まで充電される充電電気量に相当する量である。このようにして得られたＳＯＣ５０％の負極は、４μｍの成膜厚みを有していた。この負極と負極集電体との負極積層体を用いた以外、実施例１と同様の方法により蓄電デバイスを作製した。 As a result of confirming the negative electrode capacity by the same method as in Example 1, the reversible capacity capable of charge / discharge is 2.1 mAh (capacity per unit area: 1.5 mAh / cm 2 ), and the irreversible capacity does not contribute to charge / discharge. Was 0.1 mAh.
In this example, a 4 μm-thick lithium metal layer was formed on the negative electrode surface obtained above by a vapor deposition method, and the SOC of the negative electrode was adjusted to 50%. The lithium metal deposited on the surface of the negative electrode is absorbed by the negative electrode without being immersed in the electrolyte, and the negative electrode is charged (lithium charging). In addition to the irreversible capacity of the negative electrode, this lithium charge amount is an amount corresponding to the charge electricity amount charged to SOC 50%. The SOC 50% negative electrode thus obtained had a film thickness of 4 μm. An electricity storage device was produced in the same manner as in Example 1 except that this negative electrode laminate of the negative electrode and the negative electrode current collector was used.
《比較例１》
　負極活物質として、ＳｉＯ粒子（高純度科学研究所（株）製）を用い、自動乳鉢により粒径４４μｍ以下に粉砕整粒したものを負極活物質として用いた。この負極活物質、グラファイト（電子伝導助材）、およびポリアクリル酸（バインダー）をそれぞれ重量比４５：４０：１５の割合で混合して負極合剤を得た。この負極合剤を、負極集電体である厚み１００μｍのニッケルメッシュに圧着し、厚み７５μｍの負極（合剤層）を形成した。
　上記で得られた負極について、以下のようにして容量の確認、および電気化学的充電方法による充電処理を行った。上記で得られた負極と、リチウム金属（厚み３００μｍ）である対極とを、多孔質ポリエチレンシートからなるセパレータ（厚み２０μｍ）を挟んで対向させてコイン型蓄電デバイスを作製した。そして、この蓄電デバイスを３回充放電した。このとき、電流値０．５ｍＡ、上限電圧１．５Ｖ、および下限電圧０Ｖとした。この充放電により、充放電が可能な可逆容量が１４ｍＡｈであり、充放電に寄与しない不可逆容量が９ｍＡｈであることを確認した。可逆容量の５０％（ＳＯＣ５０％）まで充電した後、コイン型蓄電デバイスを分解し、負極集電体と負極とからなる負極積層体を取り出した。この負極積層体を用いた以外、実施例１と同様の方法により蓄電デバイスを作製した。 << Comparative Example 1 >>
As the negative electrode active material, SiO particles (manufactured by High Purity Science Laboratory Co., Ltd.) were used, and those pulverized and sized to a particle size of 44 μm or less with an automatic mortar were used as the negative electrode active material. This negative electrode active material, graphite (electron conduction aid), and polyacrylic acid (binder) were mixed in a weight ratio of 45:40:15, respectively, to obtain a negative electrode mixture. This negative electrode mixture was pressure-bonded to a 100 μm-thick nickel mesh as a negative electrode current collector to form a 75 μm-thick negative electrode (mixture layer).
About the negative electrode obtained above, the capacity | capacitance confirmation and the charging process by the electrochemical charging method were performed as follows. The negative electrode obtained above and a counter electrode made of lithium metal (thickness: 300 μm) were opposed to each other with a separator (thickness: 20 μm) made of a porous polyethylene sheet, to produce a coin-type electricity storage device. And this electrical storage device was charged / discharged 3 times. At this time, the current value was 0.5 mA, the upper limit voltage was 1.5 V, and the lower limit voltage was 0 V. By this charge / discharge, it was confirmed that the reversible capacity capable of charge / discharge was 14 mAh, and the irreversible capacity not contributing to charge / discharge was 9 mAh. After charging to 50% of the reversible capacity (SOC 50%), the coin-type electricity storage device was disassembled, and a negative electrode laminate composed of a negative electrode current collector and a negative electrode was taken out. An electricity storage device was produced in the same manner as in Example 1 except that this negative electrode laminate was used.
《比較例２》
　負極厚みを７５μｍから５０μｍに変更する以外、比較例１と同様の方法によりニッケルメッシュ（負極集電体）表面に、バインダーを含む厚み５０μｍの負極を形成した。得られた負極について、比較例１と同様の方法により、容量の確認および充電処理を行った。得られた負極の充放電可能な可逆容量が９ｍＡｈであり、充放電に寄与しない不可逆容量が６ｍＡｈであることを確認した。可逆容量の５０％（ＳＯＣ５０％）まで充電した後、コイン型蓄電デバイスを分解し、負極集電体と負極とからなる負極積層体のみ取り出した。この負極積層体を用いる以外、実施例１と同様の方法により蓄電デバイスを作製した。 << Comparative Example 2 >>
A negative electrode having a thickness of 50 μm containing a binder was formed on the surface of the nickel mesh (negative electrode current collector) in the same manner as in Comparative Example 1 except that the negative electrode thickness was changed from 75 μm to 50 μm. About the obtained negative electrode, the capacity | capacitance confirmation and the charge process were performed by the method similar to the comparative example 1. FIG. It confirmed that the reversible capacity | capacitance which can be charged / discharged of the obtained negative electrode was 9 mAh, and the irreversible capacity | capacitance which does not contribute to charging / discharging was 6 mAh. After charging to 50% of reversible capacity (SOC 50%), the coin-type electricity storage device was disassembled, and only the negative electrode laminate composed of the negative electrode current collector and the negative electrode was taken out. An electricity storage device was produced in the same manner as in Example 1 except that this negative electrode laminate was used.
《比較例３》
　比較例２と同じ負極に対し機械的充電方法により充電処理を行った。すなわち、負極上に、蒸着法により厚み３８μｍのＬｉ金属層を形成した。この層は、負極の不可逆容量に加えて、負極の有する可逆容量の５０％ＳＯＣまで充電することのできる電気量に相当するＬｉ量を含む。Ｌｉ蒸着後、負極表面の全面が銀色に着色しており、Ｌｉの析出が確認され、負極へのＬｉの充電反応は完全には起こらなかった。また、この負極と負極集電体との負極積層体を非水電解液に浸漬すると、負極が負極集電体から剥がれ、蓄電デバイスとしての評価を行うことができなかった。これは、Ｌｉの蒸着により、負極中のバインダーの劣化が起こったためと考えられる。 << Comparative Example 3 >>
The same negative electrode as Comparative Example 2 was charged by a mechanical charging method. That is, a Li metal layer having a thickness of 38 μm was formed on the negative electrode by vapor deposition. In addition to the irreversible capacity of the negative electrode, this layer contains an amount of Li corresponding to the amount of electricity that can be charged to 50% SOC of the reversible capacity of the negative electrode. After the deposition of Li, the entire surface of the negative electrode was colored silver, Li deposition was confirmed, and the charging reaction of Li to the negative electrode did not occur completely. Moreover, when the negative electrode laminate of the negative electrode and the negative electrode current collector was immersed in a nonaqueous electrolytic solution, the negative electrode was peeled off from the negative electrode current collector, and evaluation as an electricity storage device could not be performed. This is presumably because the binder in the negative electrode was deteriorated by the deposition of Li.
　実施例１～２および比較例１～２の蓄電デバイスについて、充放電容量評価を行った。なお、実施例１～２および比較例１～２の蓄電デバイスは、正極容量が０．０８ｍＡｈであり、正極容量に対して十分過剰量の可逆容量を有する負極を用い、負極容量は正極容量よりも十分に大きい。したがって、これらの蓄電デバイスの理論充放電容量は０．０８ｍＡｈである。
　充放電容量の評価は、０．５ｍＡ、４ｍＡ、または１２ｍＡの電流値で定電流充放電を行い、充電上限電圧３．７５Ｖ、放電下限電圧２．７５Ｖとし、充電休止時間および放電休止時間をそれぞれ１分として行った。充電休止時間とは、充電終了後、次の放電を開始するまでの時間である。放電休止時間とは、放電終了後、次の充電を開始するまでの時間である。この充放電を３回繰り返し、３回目の放電容量を充放電容量とした。その評価結果を表１に示す。 The electricity storage devices of Examples 1 and 2 and Comparative Examples 1 and 2 were evaluated for charge / discharge capacity. The electricity storage devices of Examples 1 and 2 and Comparative Examples 1 and 2 have a positive electrode capacity of 0.08 mAh, and use a negative electrode having a sufficiently excessive amount of reversible capacity with respect to the positive electrode capacity. Is big enough. Therefore, the theoretical charge / discharge capacity of these electricity storage devices is 0.08 mAh.
The charge / discharge capacity is evaluated by performing constant current charge / discharge at a current value of 0.5 mA, 4 mA, or 12 mA to obtain a charge upper limit voltage of 3.75 V and a discharge lower limit voltage of 2.75 V. It took as 1 minute. The charging pause time is the time from the end of charging until the start of the next discharge. The discharge pause time is the time from the end of discharge until the start of the next charge. This charge / discharge was repeated three times, and the third discharge capacity was defined as the charge / discharge capacity. The evaluation results are shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１から次のことが明らかとなった。従来の蓄電デバイスである、比較例１および２の蓄電デバイスは、電流値が０．５ｍＡと小さい場合には、０．０８ｍＡｈとほぼ理論容量が充放電できるものの、充放電時の電流値を４ｍＡ、１２ｍＡと大きくするにつれて、充放電容量の低下が見られた。特に、電流値１２ｍＡの時には、充放電電気量が極端に低下した。
　これに比べて、バインダーを含まず、負極集電体上に直接形成された厚み１０μｍ以下の負極を用いた実施例１および２の本発明の蓄電デバイスでは、電流値が０．５ｍＡ、４ｍＡ、１２ｍＡと大きくなっても、大部分の充放電電気量が維持できることが確認できた。すなわち、従来よりも高出力の蓄電デバイスを提供することができた。また、比較例３の有機バインダーを含んだ負極を用いている蓄電デバイスでは、予め負極に蒸着法によりリチウムを吸蔵させることができなかった。これに対して、実施例１～２の蓄電デバイスでは、組立前に蒸着法により負極にリチウムを吸蔵させることができるので、加工性の面でも優れていることがわかった。 From Table 1, the following became clear. When the current value is as small as 0.5 mA, the power storage devices of Comparative Examples 1 and 2, which are conventional power storage devices, can charge and discharge with a theoretical capacity of 0.08 mAh, but the current value during charging and discharging is 4 mA. As the current was increased to 12 mA, the charge / discharge capacity decreased. In particular, when the current value was 12 mA, the charge / discharge electricity amount was extremely reduced.
In comparison with this, in the electricity storage device of Examples 1 and 2 of the present invention using a negative electrode having a thickness of 10 μm or less and not directly including a binder and formed directly on the negative electrode current collector, the current value was 0.5 mA, 4 mA, It was confirmed that even if the current was increased to 12 mA, most of the charge / discharge electricity could be maintained. In other words, it has been possible to provide a power storage device having a higher output than before. Moreover, in the electrical storage device using the negative electrode containing the organic binder of Comparative Example 3, lithium could not be occluded in advance by a vapor deposition method. In contrast, the power storage devices of Examples 1 and 2 were found to be excellent in workability because lithium could be occluded in the negative electrode by vapor deposition before assembly.
　実施例１（負極厚み９μｍ）に比べて、実施例２（負極厚み４μｍ）の蓄電デバイスの方が、電流値１２ｍＡの際の放電容量が大きくなっており、より高出力な蓄電デバイスが得られた。これは、実施例２の蓄電デバイスにおける負極の厚みが４μｍであり、実施例１の蓄電デバイスの負極厚みよりも薄かったためであると考えられる。したがって、負極の厚みは５μｍ以下が好ましいことがわかった。 Compared with Example 1 (negative electrode thickness 9 μm), the electricity storage device of Example 2 (negative electrode thickness 4 μm) has a larger discharge capacity at a current value of 12 mA, and a higher output electricity storage device is obtained. It was. This is considered to be because the thickness of the negative electrode in the electricity storage device of Example 2 was 4 μm, which was thinner than the thickness of the negative electrode of the electricity storage device in Example 1. Therefore, it was found that the thickness of the negative electrode is preferably 5 μm or less.
　実施例１および２の蓄電デバイスでは、動作電圧（放電下限電圧～充電上限電圧）２．７５～３．７５Ｖと高電圧での充放電が可能であることから、正極活物質および負極活物質の両方に活性炭を用いた従来の蓄電デバイスよりも高エネルギー密度化することが可能である。また、本発明の蓄電デバイスで用いる負極は厚み１０μｍ以下の薄膜である。従って、本発明では、蓄電デバイスの高容量化と小型化とを同時に達成できる。 In the electricity storage devices of Examples 1 and 2, since charging / discharging at a high voltage of 2.75 to 3.75 V operating voltage (discharge lower limit voltage to charge upper limit voltage) is possible, the positive electrode active material and the negative electrode active material It is possible to increase the energy density as compared with the conventional power storage device using activated carbon for both. The negative electrode used in the electricity storage device of the present invention is a thin film having a thickness of 10 μm or less. Therefore, according to the present invention, it is possible to simultaneously achieve high capacity and downsizing of the electricity storage device.
《実施例３》
　以下正極積層体を用いた以外、実施例１と同様の方法により蓄電デバイスを作製した。
　正極を構成する正極活物質として、化学構造式（４）で表されるモノマー単位のホモポリマーであるπ共役電子雲を有する有機化合物ポリマー（以下「π共役ポリマー」とする）を用いた。このπ共役ポリマーは、ポリビニルアルコールと、テトラチアフルバレンにカルボキシル基を導入した化学構造式（５）の分子構造を有する化合物を脱水縮合させることによって合成した。このπ共役ポリマーは、数平均分子量：約１５０００、理論最大容量：２００ｍＡｈ／ｇであった。 Example 3
Hereinafter, an electricity storage device was produced in the same manner as in Example 1 except that the positive electrode laminate was used.
As the positive electrode active material constituting the positive electrode, an organic compound polymer having a π-conjugated electron cloud (hereinafter referred to as “π-conjugated polymer”), which is a homopolymer of monomer units represented by the chemical structural formula (4), was used. This π-conjugated polymer was synthesized by dehydrating and condensing polyvinyl alcohol and a compound having a molecular structure represented by the chemical structural formula (5) in which a carboxyl group was introduced into tetrathiafulvalene. This π-conjugated polymer had a number average molecular weight of about 15000 and a theoretical maximum capacity of 200 mAh / g.
Figure JPOXMLDOC01-appb-C000004
Figure JPOXMLDOC01-appb-C000004
　π共役ポリマー３７．５ｍｇとアセチレンブラック１００ｍｇとを均一に混合し、さらにポリテトラフルオロエチレン２５ｍｇを加えて混合し、正極合剤を調製した。この正極合剤をアルミニウム製金網からなる正極集電体上に圧着し、真空乾燥した。これを直径１３．５ｍｍの円盤状に打ち抜き裁断して、正極と正極集電体との積層体を作製した。このとき、正極活物質の塗布重量は正極単位面積あたり０．５ｍｇ／ｃｍ２、正極厚みは９０μｍ、正極理論容量は０．１４ｍＡｈであった。 37.5 mg of π-conjugated polymer and 100 mg of acetylene black were uniformly mixed, and 25 mg of polytetrafluoroethylene was further added and mixed to prepare a positive electrode mixture. This positive electrode mixture was pressure-bonded onto a positive electrode current collector made of an aluminum wire mesh and vacuum-dried. This was punched and cut into a disk shape having a diameter of 13.5 mm to produce a laminate of a positive electrode and a positive electrode current collector. At this time, the coating weight of the positive electrode active material was 0.5 mg / cm 2 per unit area of the positive electrode, the positive electrode thickness was 90 μm, and the positive electrode theoretical capacity was 0.14 mAh.
《実施例４》
　以下の正極積層体を用いた以外、実施例１と同様の方法により蓄電デバイスを作製した。
　正極を構成する正極活物質として、化学構造式（６）で表されるモノマー単位のホモポリマーであるラジカルを有する有機化合物ポリマー（以下「ラジカルポリマー」とする）を用いた。このラジカルポリマーは、化学構造式（７）で表されるモノマー化合物をラジカル重合させた後、窒素原子に結合する水素原子を酸化することによって合成した。このラジカルポリマーは、数平均分子量：約１０００００、理論最大容量：１１０ｍＡｈ／ｇであった。 Example 4
An electricity storage device was produced in the same manner as in Example 1 except that the following positive electrode laminate was used.
As the positive electrode active material constituting the positive electrode, an organic compound polymer having a radical that is a homopolymer of the monomer unit represented by the chemical structural formula (6) (hereinafter referred to as “radical polymer”) was used. This radical polymer was synthesized by radical polymerization of a monomer compound represented by the chemical structural formula (7) and then oxidizing a hydrogen atom bonded to a nitrogen atom. This radical polymer had a number average molecular weight of about 100,000 and a theoretical maximum capacity of 110 mAh / g.
Figure JPOXMLDOC01-appb-C000005
Figure JPOXMLDOC01-appb-C000005
　ラジカルポリマー３７．５ｍｇとアセチレンブラック１００ｍｇとを均一に混合し、さらにポリテトラフルオロエチレン２５ｍｇを加えて混合し、正極合剤を調製した。この正極合剤をアルミニウム製金網からなる正極集電体上に圧着し、真空乾燥した。これを直径１３．５ｍｍの円盤状に打ち抜き裁断して、正極と正極集電体との積層体を作製した。このとき、正極活物質の塗布重量は正極単位面積あたり０．５ｍｇ／ｃｍ２、正極厚みは９０μｍ、正極理論容量は０．０８ｍＡｈであった。 37.5 mg of radical polymer and 100 mg of acetylene black were uniformly mixed, and 25 mg of polytetrafluoroethylene was further added and mixed to prepare a positive electrode mixture. This positive electrode mixture was pressure-bonded onto a positive electrode current collector made of an aluminum wire mesh and vacuum-dried. This was punched and cut into a disk shape having a diameter of 13.5 mm to produce a laminate of a positive electrode and a positive electrode current collector. At this time, the coating weight of the positive electrode active material was 0.5 mg / cm 2 per unit area of the positive electrode, the positive electrode thickness was 90 μm, and the positive electrode theoretical capacity was 0.08 mAh.
　実施例３～４の蓄電デバイスについて、充放電容量評価を行った。充放電容量の評価は、０．５ｍＡ、４ｍＡ、または１２ｍＡの電流値で定電流充放電を行い、充電上限電圧３．７５Ｖ、放電下限電圧２．７５Ｖとし、充電休止時間および放電休止時間をそれぞれ１分として行った。充電休止時間とは、充電終了後、次の放電を開始するまでの時間である。放電休止時間とは、放電終了後、次の充電を開始するまでの時間である。この充放電を３回繰り返し、３回目の放電容量を充放電容量とした。その評価結果を表２に示す。 The charge / discharge capacity evaluation was performed on the electricity storage devices of Examples 3 to 4. The charge / discharge capacity is evaluated by performing constant current charge / discharge at a current value of 0.5 mA, 4 mA, or 12 mA to obtain a charge upper limit voltage of 3.75 V and a discharge lower limit voltage of 2.75 V. It took as 1 minute. The charging pause time is the time from the end of charging until the start of the next discharge. The discharge pause time is the time from the end of discharge until the start of the next charge. This charge / discharge was repeated three times, and the third discharge capacity was defined as the charge / discharge capacity. The evaluation results are shown in Table 2.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表２から次のことが明らかとなった。実施例３および４の蓄電デバイスでは、電流値が０．５ｍＡ、４ｍＡ、１２ｍＡと大きくなっても、大部分の充放電電気量を維持できることが確認できた。すなわち、従来よりも高出力の蓄電デバイスを提供することができた。また、実施例３～４の蓄電デバイスでは、組立前に蒸着法により負極にリチウムを吸蔵できており、加工性の面でも優れていることがわかった。この結果から、酸化還元可能な有機化合物を正極活物質として用いた場合でも、高出力な蓄電デバイスが得られることを確認できた。
　また、正極活物質である酸化還元可能な有機化合物は、活性炭よりもさらに高容量であり、かつ高電圧での動作を可能にすることから、一層高容量で実用性に富む蓄電デバイスが得られる。 From Table 2, the following became clear. In the electricity storage devices of Examples 3 and 4, it was confirmed that even when the current value was increased to 0.5 mA, 4 mA, and 12 mA, most of the charge / discharge electricity could be maintained. In other words, it has been possible to provide a power storage device having a higher output than before. In addition, it was found that in the electricity storage devices of Examples 3 to 4, lithium was occluded in the negative electrode by a vapor deposition method before assembly, and the workability was also excellent. From this result, it was confirmed that a high-output electricity storage device was obtained even when an organic compound capable of oxidation and reduction was used as the positive electrode active material.
In addition, the organic compound capable of redox which is a positive electrode active material has a higher capacity than activated carbon and enables operation at a high voltage, so that an electric storage device having higher capacity and practicality can be obtained. .
《実施例５》
　本実施例では、負極の厚みと正極の厚みとの関係について検討した。
　以下の方法により負極を作製した。
　負極集電体に銅箔（比表面積１１．６、表面粗さ（Ｒａ）２．０μｍ、厚み４３μｍ）を用いた。電子線加熱蒸着法により、この銅箔上に珪素酸化物（ＳｉＯｘ）の薄膜からなる負極（厚み６μｍ、比表面積４．２）を形成した。
　このようにして、負極集電体と負極とからなる負極積層体を得た。負極厚みの調整は蒸着時間を調整することで行った。電子線加熱蒸着の条件は次の通りである。蒸着源として純度９９．９９９９％のケイ素金属（（株）高純度化学研究所製）を用い、真空チャンバー内に純度９９．７％の酸素ガス（日本酸素（株）製）を導入して真空度３×１０－３Ｐに調整した。また、蒸着源に照射する電子ビームの加速電圧を８ｋＶとし、エミッションを５００ｍＡとした。負極形成後、蛍光Ｘ線分析により組成を分析した結果、負極中のＳｉとＯとのモル比率が１：０．６であった。このことから、負極を構成する酸化珪素（ＳｉＯｘ）のｘ値は０．６であることが判った。 Example 5
In this example, the relationship between the thickness of the negative electrode and the thickness of the positive electrode was examined.
A negative electrode was produced by the following method.
A copper foil (specific surface area 11.6, surface roughness (Ra) 2.0 μm, thickness 43 μm) was used for the negative electrode current collector. A negative electrode (thickness 6 μm, specific surface area 4.2) made of a thin film of silicon oxide (SiOx) was formed on the copper foil by electron beam heating vapor deposition.
Thus, the negative electrode laminated body which consists of a negative electrode collector and a negative electrode was obtained. The negative electrode thickness was adjusted by adjusting the deposition time. The conditions for electron beam heating vapor deposition are as follows. Silicon metal with a purity of 99.9999% (manufactured by Kojundo Chemical Laboratory Co., Ltd.) is used as a vapor deposition source, and oxygen gas with a purity of 99.7% (manufactured by Nippon Oxygen Co., Ltd.) is introduced into the vacuum chamber and vacuum is applied. The degree was adjusted to 3 × 10 −3 P. In addition, the acceleration voltage of the electron beam applied to the vapor deposition source was 8 kV, and the emission was 500 mA. As a result of analyzing the composition by fluorescent X-ray analysis after forming the negative electrode, the molar ratio of Si and O in the negative electrode was 1: 0.6. From this, it was found that the x value of silicon oxide (SiOx) constituting the negative electrode was 0.6.
　次に、上記で得られた負極の容量を、以下のようにして確認した。上記と同じ方法で作製した負極積層体を、直径１３．５ｍｍの円盤状に打ち抜き裁断したものと、リチウム金属（厚み３００μｍ）からなる対極とを、多孔質ポリエチレンシートからなるセパレータ（厚み２０μｍ）を介して対向配置してコイン型蓄電デバイスを作製した。この蓄電デバイスを３回充放電した。このとき、電流値０．５ｍＡ、上限電圧１．５Ｖ、および下限電圧０Ｖとした。この充放電により、充放電可能な可逆容量が１．８ｍＡｈ（単位面積あたり容量１．３ｍＡｈ／ｃｍ２）であり、充放電に寄与しない不可逆容量が０．５ｍＡｈであることを確認した。 Next, the capacity of the negative electrode obtained above was confirmed as follows. A separator (thickness 20 μm) made of a porous polyethylene sheet is formed by punching and cutting a negative electrode laminate produced by the same method as above into a disc shape having a diameter of 13.5 mm and a counter electrode made of lithium metal (thickness 300 μm). The coin-type electricity storage device was manufactured by facing each other. This electricity storage device was charged and discharged three times. At this time, the current value was 0.5 mA, the upper limit voltage was 1.5 V, and the lower limit voltage was 0 V. This charge / discharge confirmed that the reversible capacity capable of charge / discharge was 1.8 mAh (capacity per unit area: 1.3 mAh / cm 2 ), and the irreversible capacity not contributing to charge / discharge was 0.5 mAh.
　最後に、以下のようにして、負極のＳＯＣを調整した。すなわち、負極に対して機械的充電を行い、次に、電気化学的充電により負極のＳＯＣを微調整した。具体的には、上記で得られた負極積層体における負極表面に、不可逆容量（０．５ｍＡｈ）に相当する厚み２．６μｍのリチウム金属を蒸着法により形成した。なお、負極の表面に蒸着されたリチウムは、負極を電解質に浸漬しなくても負極に吸収され、負極において不可逆容量分が充電された。さらに、機械的充電後の負極積層体を直径１３．５ｍｍの円盤状に打ち抜き裁断したものと、リチウム金属（厚み３００μｍ）からなる対極とを、セパレータを挟んで対向させてコイン型蓄電デバイスを作製した。そして、負極のＳＯＣが５０％（充電電気量０．０５ｍＡｈ）となるまで、０．５ｍＡの定電流で充電した。なお、セパレータおよび電解質には、実施例１と同じものを用いた。
　このようにして、負極のＳＯＣが５０％となるまで充電した後、コイン型蓄電デバイスを分解し、ＳＯＣが５０％の負極を得た。このとき得られた負極の厚みは９μｍであった。 Finally, the SOC of the negative electrode was adjusted as follows. That is, the negative electrode was mechanically charged, and then the SOC of the negative electrode was finely adjusted by electrochemical charging. Specifically, a lithium metal having a thickness of 2.6 μm corresponding to an irreversible capacity (0.5 mAh) was formed on the negative electrode surface of the negative electrode laminate obtained above by an evaporation method. Note that lithium deposited on the surface of the negative electrode was absorbed by the negative electrode without immersing the negative electrode in the electrolyte, and the irreversible capacity was charged in the negative electrode. Further, a coin-type electricity storage device is fabricated by punching and cutting a negative electrode laminate after mechanical charging into a disk shape having a diameter of 13.5 mm and a counter electrode made of lithium metal (thickness 300 μm) with a separator interposed therebetween. did. Then, the negative electrode was charged with a constant current of 0.5 mA until the SOC of the negative electrode reached 50% (charged electric charge 0.05 mAh). The same separator and electrolyte as those used in Example 1 were used.
Thus, after charging until the SOC of the negative electrode reached 50%, the coin-type electricity storage device was disassembled to obtain a negative electrode with an SOC of 50%. The thickness of the negative electrode obtained at this time was 9 μm.
　蓄電デバイス構成時の正極の単位面積あたりの活物質重量、および電極容量を実施例１と同じ値とし、正極の厚みを表３に示す値に変えた以外は、実施例１と同様の方法により正極積層体（Ａ－１）～（Ａ－７）を作製した。
　なお、正極の厚み４５、６０、７０、１００、１２５、３０、および３５μｍは、活性炭粉末（比表面積１７００ｍ2／ｇ、平均粒子径２μｍ）１００ｍｇに対する、電子伝導助材としてのアセチレンブラックの配合割合を、それぞれ２０、３０、３５、５０、６２、１５、および１８ｍｇに変えることにより調整した。
　そして、上記で得られた負極積層体および正極積層体（Ａ－１）～（Ａ－７）を用いて、実施例１と同様の方法により蓄電デバイス（Ａ－１）～（Ａ－７）を作製した。 According to the same method as in Example 1, except that the active material weight per unit area of the positive electrode and the electrode capacity when the power storage device was configured were the same values as in Example 1 and the thickness of the positive electrode was changed to the values shown in Table 3. Positive electrode laminates (A-1) to (A-7) were produced.
The positive electrode thicknesses 45, 60, 70, 100, 125, 30, and 35 μm are blended ratios of acetylene black as an electron conduction aid with respect to 100 mg of activated carbon powder (specific surface area 1700 m 2 / g, average particle diameter 2 μm). Were adjusted to 20, 30, 35, 50, 62, 15, and 18 mg, respectively.
Then, using the negative electrode laminate and the positive electrode laminates (A-1) to (A-7) obtained above, the electricity storage devices (A-1) to (A-7) were produced in the same manner as in Example 1. Was made.
　蓄電デバイス（Ａ－１）～（Ａ－７）について、充放電容量評価を行った。
　充放電容量の評価は、４ｍＡまたは１２ｍＡの定電流充放電で、充電上限電圧３．７５Ｖ、放電下限電圧２．７５Ｖとし、充電終了後、次の放電を開始するまでの充電休止時間、および、放電終了後、次の充電を開始するまでの放電休止時間は、それぞれ１分間とした。この充放電を３回繰り返し、３回目の放電容量を充放電容量とした。
　これらの評価結果を表１に示す。同様に表１中に、各蓄電デバイスに用いた正極と負極の厚み、およびその比率を記載した。 For the electricity storage devices (A-1) to (A-7), charge / discharge capacity was evaluated.
The evaluation of the charge / discharge capacity is a constant current charge / discharge of 4 mA or 12 mA, a charge upper limit voltage of 3.75 V, a discharge lower limit voltage of 2.75 V, a charge pause time until the start of the next discharge after the end of charge, and The discharge pause time from the end of discharge until the start of the next charge was 1 minute each. This charge / discharge was repeated three times, and the third discharge capacity was defined as the charge / discharge capacity.
These evaluation results are shown in Table 1. Similarly, in Table 1, the thicknesses and ratios of the positive electrode and the negative electrode used for each power storage device are described.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　表３に示すように、電流値４ｍＡで蓄電デバイスを充放電した場合、正極の厚みが負極の厚みの５倍以上である蓄電デバイス（Ａ－１）～（Ａ－５）では、正極の厚みが負極の厚みの５倍未満である蓄電デバイス（Ａ－６）および（Ａ－７）と比べて０．０８ｍＡｈの高い容量が得られた。
　以上のことから、正極の厚みが負極の厚みの５倍以上であることが好ましいことがわかった。なお、蓄電デバイス（Ａ－１）～（Ａ－７）は、正極容量が０．０８ｍＡｈであり、負極容量が正極容量に対して十分過剰量の可逆容量を有しているため、理論充放電容量は０．０８ｍＡｈである。 As shown in Table 3, when the storage device was charged / discharged at a current value of 4 mA, the thickness of the positive electrode was measured in the storage devices (A-1) to (A-5) in which the thickness of the positive electrode was 5 times or more the thickness of the negative electrode. As compared with the electricity storage devices (A-6) and (A-7) having a thickness of less than 5 times the thickness of the negative electrode, a high capacity of 0.08 mAh was obtained.
From the above, it was found that the thickness of the positive electrode is preferably 5 times or more the thickness of the negative electrode. The electricity storage devices (A-1) to (A-7) have a positive electrode capacity of 0.08 mAh, and the negative electrode capacity has a sufficiently excessive amount of reversible capacity relative to the positive electrode capacity. The capacity is 0.08 mAh.
　また、電流値１２ｍＡで蓄電デバイスを充放電した場合、正極の厚みが負極の厚みの１０倍以上を有する蓄電デバイス（Ａ－４）および（Ａ－５）では、正極の厚みが負極の厚みの１０倍未満の蓄電デバイス（Ａ－１）～（Ａ－３）、（Ａ－６）および（Ａ－７）に比べて高容量が得られることがわかった。
　大電流で充放電した場合でも高容量が得られるということは、高容量を有し、かつ出力特性に優れた蓄電デバイスであるということを意味している。すなわち、蓄電デバイス内部に十分量のアニオンおよびカチオンを保持させることができるため、イオンの伝導性、および拡散性に優れた蓄電デバイスを提供することができると考えられる。
　以上のことから、正極の厚みが負極の厚みの１０倍以上であることがより好ましいことがわかった。 In addition, when the electricity storage device is charged / discharged at a current value of 12 mA, in the electricity storage devices (A-4) and (A-5) in which the thickness of the positive electrode is 10 times or more the thickness of the negative electrode, the thickness of the positive electrode is equal to the thickness of the negative electrode. It was found that a capacity higher than that of the electricity storage devices (A-1) to (A-3), (A-6) and (A-7) of less than 10 times was obtained.
The fact that a high capacity can be obtained even when charging / discharging with a large current means that the power storage device has a high capacity and excellent output characteristics. That is, since a sufficient amount of anions and cations can be retained inside the electricity storage device, it is considered that an electricity storage device having excellent ion conductivity and diffusibility can be provided.
From the above, it was found that the thickness of the positive electrode is more preferably 10 times or more the thickness of the negative electrode.
《実施例６》
　本実施例では、負極の比表面積について検討した。
　下記の負極積層体（Ｂ－１）～（Ｂ－３）を用いて、実施例１と同様の方法により、蓄電デバイス（Ｂ－１）～（Ｂ－３）を作製した。
　負極積層体（Ｂ－１）は以下の方法により作製した。
　負極集電体には、電解銅箔（比表面積１１．６、算術平均表面粗さ（Ｒａ）１．８μｍ、厚み４３μｍ）を用いた。この銅箔上に、ＲＦスパッタリングにより、珪素の薄膜からなる負極を形成した。このようにして、負極集電体および負極からなる負極積層体を得た。
　ＲＦスパッタリングは、以下のようにして行った。直径１０インチの溶融シリコンターゲット（珪素純度９９％）を用い、ターゲットと基板との間の距離を７ｃｍとし、アルゴンを５０ｓｃｃｍで導入した。真空雰囲気圧力１．１Ｐａ、印加電力１ｋｗ、および成膜時間１時間とした。 Example 6
In this example, the specific surface area of the negative electrode was examined.
Using the following negative electrode laminates (B-1) to (B-3), electricity storage devices (B-1) to (B-3) were produced in the same manner as in Example 1.
The negative electrode laminate (B-1) was produced by the following method.
For the negative electrode current collector, an electrolytic copper foil (specific surface area 11.6, arithmetic average surface roughness (Ra) 1.8 μm, thickness 43 μm) was used. A negative electrode made of a silicon thin film was formed on the copper foil by RF sputtering. Thus, the negative electrode laminated body which consists of a negative electrode collector and a negative electrode was obtained.
RF sputtering was performed as follows. A 10-inch diameter molten silicon target (silicon purity 99%) was used, the distance between the target and the substrate was 7 cm, and argon was introduced at 50 sccm. The vacuum atmosphere pressure was 1.1 Pa, the applied power was 1 kw, and the film formation time was 1 hour.
　得られた負極を走査型電子顕微鏡（ＳＥＭ）により観察した結果、負極は厚み０．３μｍの薄膜であった。図１３は負極集電体５３の厚み方向断面の顕微鏡写真である。図１４は負極５２と負極集電体５３との積層体の厚み方向断面の顕微鏡写真である。図１４から、負極集電体５３である電解銅箔の表面（上面）に、該電解銅箔表面の凹凸に追従するように、負極５２である薄膜が形成されることが明らかである。また、負極５２表面の比表面積は１１．４であった。負極５２は、その表面が負極集電体５３表面の凹凸をほぼ正確に再現するので、負極集電体５３表面の比表面積に近い値が得られた。 As a result of observing the obtained negative electrode with a scanning electron microscope (SEM), the negative electrode was a thin film having a thickness of 0.3 μm. FIG. 13 is a micrograph of a cross section in the thickness direction of the negative electrode current collector 53. FIG. 14 is a photomicrograph of the cross section in the thickness direction of the laminate of the negative electrode 52 and the negative electrode current collector 53. From FIG. 14, it is apparent that a thin film that is the negative electrode 52 is formed on the surface (upper surface) of the electrolytic copper foil that is the negative electrode current collector 53 so as to follow the unevenness of the surface of the electrolytic copper foil. Moreover, the specific surface area of the negative electrode 52 surface was 11.4. Since the surface of the negative electrode 52 reproduces the unevenness of the surface of the negative electrode current collector 53 almost accurately, a value close to the specific surface area of the surface of the negative electrode current collector 53 was obtained.
　次に、上記で得られた負極の容量を、以下のようにして確認した。上記と同様にして作製された負極積層体を直径１３．５ｍｍの円盤状に打ち抜き裁断したものと、リチウム金属板（厚み３００μｍ）からなる対極とを、多孔質ポリエチレンシートからなるセパレータ（厚み２０μｍ）を介して対向配置させてコイン型蓄電デバイスを作製した。この蓄電デバイスを３回充放電した。このとき、電流値０．１ｍＡ、上限電圧１．５Ｖ、および下限電圧０Ｖとした。この充放電により、充放電可能な可逆容量が０．４４ｍＡｈ／ｃｍ２であり、充放電に寄与しない不可逆容量が０．０３ｍＡｈ／ｃｍ2であることを確認した。 Next, the capacity of the negative electrode obtained above was confirmed as follows. A separator made of a porous polyethylene sheet (thickness: 20 μm) obtained by punching and cutting a negative electrode laminate produced in the same manner as above into a disc shape having a diameter of 13.5 mm and a counter electrode made of a lithium metal plate (thickness: 300 μm) A coin-type electricity storage device was manufactured by placing the two facing each other. This electricity storage device was charged and discharged three times. At this time, the current value was 0.1 mA, the upper limit voltage was 1.5V, and the lower limit voltage was 0V. This charge / discharge confirmed that the reversible capacity capable of charge / discharge was 0.44 mAh / cm 2 and the irreversible capacity not contributing to charge / discharge was 0.03 mAh / cm 2 .
　次に、負極のＳＯＣを５０％に調整した。すなわち、蒸着法により、厚み１．３μｍのリチウム金属層を負極表面に形成した。これを直径１３．５ｍｍの円盤状に打ち抜き裁断してリチウム金属、負極および負極集電体の積層体を形成した。なお、負極の表面に蒸着されたリチウム金属は、負極を電解質に浸漬しなくても負極に吸収され、負極が充電（リチウム充電）される。また、このリチウム充電量は、負極の不可逆容量に加えて、ＳＯＣ５０％まで充電される充電電気量に相当する量である。ＳＯＣ調整後の負極厚みは０．６μｍであった。 Next, the SOC of the negative electrode was adjusted to 50%. That is, a lithium metal layer having a thickness of 1.3 μm was formed on the negative electrode surface by vapor deposition. This was punched and cut into a disk shape having a diameter of 13.5 mm to form a laminate of lithium metal, a negative electrode, and a negative electrode current collector. The lithium metal deposited on the surface of the negative electrode is absorbed by the negative electrode without being immersed in the electrolyte, and the negative electrode is charged (lithium charging). In addition to the irreversible capacity of the negative electrode, this lithium charge amount is an amount corresponding to the charge electricity amount charged to SOC 50%. The negative electrode thickness after the SOC adjustment was 0.6 μm.
　負極積層体（Ｂ－２）は、以下の方法により作製した。
　負極集電体には、圧延銅箔（比表面積７．０、算術平均表面粗さ（Ｒａ）１．２４μｍ、厚み１５μｍ）を用いた。この銅箔上に、上記と同じ条件でＲＦスパッタリングし、珪素の薄膜からなる負極を形成した。このようにして、負極集電体および負極からなる負極積層体を得た。
　得られた負極を走査型電子顕微鏡（ＳＥＭ）により観察した結果、負極は厚み０．７μｍの薄膜であった。負極表面の比表面積は７．１であった。負極の表面には、負極集電体表面の凹凸がほぼ正確に再現されているので、負極集電体表面の比表面積に近い値が得られた。 The negative electrode laminate (B-2) was produced by the following method.
A rolled copper foil (specific surface area 7.0, arithmetic average surface roughness (Ra) 1.24 μm, thickness 15 μm) was used for the negative electrode current collector. On this copper foil, RF sputtering was performed under the same conditions as described above to form a negative electrode made of a silicon thin film. Thus, the negative electrode laminated body which consists of a negative electrode collector and a negative electrode was obtained.
As a result of observing the obtained negative electrode with a scanning electron microscope (SEM), the negative electrode was a thin film having a thickness of 0.7 μm. The specific surface area of the negative electrode surface was 7.1. Since the unevenness of the surface of the negative electrode current collector was almost accurately reproduced on the surface of the negative electrode, a value close to the specific surface area of the surface of the negative electrode current collector was obtained.
　また、負極の容量を上記と同様の方法により確認したところ、充放電可能な可逆容量が０．５３ｍＡｈ／ｃｍ２であり、充放電に寄与しない不可逆容量が０．０４ｍＡｈ／ｃｍ２であることを確認した。
　次に、蒸着法により、負極表面に厚み１．６μｍのリチウム金属層を形成した。これによって、負極のＳＯＣを５０％に調整した。ＳＯＣ調整後の負極厚みは１．４μｍであった。 Moreover, when the capacity | capacitance of the negative electrode was confirmed by the method similar to the above, the reversible capacity | capacitance which can be charged / discharged is 0.53 mAh / cm < 2 >, and the irreversible capacity | capacitance which does not contribute to charging / discharging is 0.04 mAh / cm < 2 >. confirmed.
Next, a lithium metal layer having a thickness of 1.6 μm was formed on the negative electrode surface by vapor deposition. As a result, the SOC of the negative electrode was adjusted to 50%. The negative electrode thickness after the SOC adjustment was 1.4 μm.
　負極積層体（Ｂ－３）は、以下の方法により作製した。
　負極集電体には、圧延銅箔（比表面積１．０、算術平均表面粗さ（Ｒａ）０．１２μｍ、厚み１５μｍ）を用いた。この銅箔上に、上記と同じ条件でＲＦスパッタリングし、珪素の薄膜からなる負極を形成した。このようにして、負極集電体および負極からなる負極積層体を得た。
　得られた負極を走査型電子顕微鏡（ＳＥＭ）により観察した結果、負極は厚み０．７μｍの薄膜であった。図１５は負極集電体６２の厚み方向断面の顕微鏡写真である。図１６は負極６１と負極集電体６２との積層体の厚み方向断面の顕微鏡写真である。図１６から、負極集電体６２である圧延銅箔の表面に、該圧延銅箔表面の凹凸に追従するように、負極６１である薄膜が形成されることが明らかである。また、負極６１表面の比表面積は１．１であった。負極６１は、その表面が負極集電体６２表面の凹凸をほぼ正確に再現するので、負極集電体６２表面の比表面積に近い値が得られた。 The negative electrode laminate (B-3) was produced by the following method.
A rolled copper foil (specific surface area 1.0, arithmetic average surface roughness (Ra) 0.12 μm, thickness 15 μm) was used for the negative electrode current collector. On this copper foil, RF sputtering was performed under the same conditions as described above to form a negative electrode made of a silicon thin film. Thus, the negative electrode laminated body which consists of a negative electrode collector and a negative electrode was obtained.
As a result of observing the obtained negative electrode with a scanning electron microscope (SEM), the negative electrode was a thin film having a thickness of 0.7 μm. FIG. 15 is a photomicrograph of a cross section in the thickness direction of the negative electrode current collector 62. FIG. 16 is a photomicrograph of the cross section in the thickness direction of the laminate of the negative electrode 61 and the negative electrode current collector 62. From FIG. 16, it is clear that a thin film that is the negative electrode 61 is formed on the surface of the rolled copper foil that is the negative electrode current collector 62 so as to follow the irregularities on the surface of the rolled copper foil. Moreover, the specific surface area of the negative electrode 61 surface was 1.1. Since the surface of the negative electrode 61 reproduces the unevenness of the surface of the negative electrode current collector 62 almost accurately, a value close to the specific surface area of the surface of the negative electrode current collector 62 was obtained.
　また、負極の容量を上記と同様の方法により確認したところ、充放電可能な可逆容量が０．５３ｍＡｈ／ｃｍ２であり、充放電に寄与しない不可逆容量が０．０４ｍＡｈ／ｃｍ２であることを確認した。
　次に、蒸着法により、負極表面に厚み１．６μｍのリチウム金属層を形成した。これによって、負極のＳＯＣを５０％に調整した。ＳＯＣ調整後の負極厚みは１．４μｍであった。 Moreover, when the capacity | capacitance of the negative electrode was confirmed by the method similar to the above, the reversible capacity | capacitance which can be charged / discharged is 0.53 mAh / cm < 2 >, and the irreversible capacity | capacitance which does not contribute to charging / discharging is 0.04 mAh / cm < 2 >. confirmed.
Next, a lithium metal layer having a thickness of 1.6 μm was formed on the negative electrode surface by vapor deposition. As a result, the SOC of the negative electrode was adjusted to 50%. The negative electrode thickness after the SOC adjustment was 1.4 μm.
　蓄電デバイス（Ｂ－１）～（Ｂ－３）について、充放電容量評価を行った。蓄電デバイス（Ｂ－１）～（Ｂ－３）は、正極容量が０．０８ｍＡｈであり、正極容量に対して十分過剰量の可逆容量を有する負極を用い、負極容量は正極容量よりも十分に大きい。従って、これらの蓄電デバイスの理論充放電容量は０．０８ｍＡｈである。
　充放電容量の評価は、０．６ｍＡ、１．８ｍＡ、または３ｍＡの定電流充放電で、充電上限電圧３．７５Ｖ、放電下限電圧２．７５Ｖとし、充電休止時間および放電休止時間をそれぞれ１分として行った。充電休止時間とは、充電終了後、次の放電を開始するまでの時間である。放電休止時間とは、放電終了後、次の充電を開始するまでの時間である。この充放電を３回繰り返し、３回目の放電容量を充放電容量とした。結果を表４に示す。なお、表４には、各蓄電デバイスにおける負極の比表面積を併記する。 For the electricity storage devices (B-1) to (B-3), a charge / discharge capacity evaluation was performed. The electricity storage devices (B-1) to (B-3) have a positive electrode capacity of 0.08 mAh, and use a negative electrode having a sufficiently excessive amount of reversible capacity with respect to the positive electrode capacity. The negative electrode capacity is sufficiently higher than the positive electrode capacity. large. Therefore, the theoretical charge / discharge capacity of these electricity storage devices is 0.08 mAh.
The charge / discharge capacity was evaluated at a constant current charge / discharge of 0.6 mA, 1.8 mA, or 3 mA, a charge upper limit voltage of 3.75 V, a discharge lower limit voltage of 2.75 V, and a charge pause time and a discharge pause time of 1 minute each. Went as. The charging pause time is the time from the end of charging until the start of the next discharge. The discharge pause time is the time from the end of discharge until the start of the next charge. This charge / discharge was repeated three times, and the third discharge capacity was defined as the charge / discharge capacity. The results are shown in Table 4. Table 4 also shows the specific surface area of the negative electrode in each power storage device.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　表４に示すように、充放電時の電流値０．６ｍＡの場合、蓄電デバイス（Ｂ－１）～（Ｂ－３）のいずれにおいても、設計容量である０．０８ｍＡｈの容量が得られた。また、充放電時の電流値が１．８ｍＡまたは３ｍＡと大きい場合でも、蓄電デバイス（Ｂ－１）および（Ｂ－２）は、ほぼ設計容量通りの良好な容量を示した。特に、蓄電デバイス（Ｂ－１）は、蓄電デバイス（Ｂ－２）に比べて、３ｍＡという大電流においてより良好な特性を示した。
　このように、蓄電デバイス（Ｂ－１）および（Ｂ－２）では、３ｍＡという大電流で充放電した場合でも高容量が得られることは、これらの蓄電デバイスが高容量でありかつ出力特性に優れることを意味する。 As shown in Table 4, when the current value during charging and discharging was 0.6 mA, a capacity of 0.08 mAh, which is the designed capacity, was obtained in any of the electricity storage devices (B-1) to (B-3). . Further, even when the current value during charging / discharging was as large as 1.8 mA or 3 mA, the electricity storage devices (B-1) and (B-2) exhibited good capacity almost as designed. In particular, the electricity storage device (B-1) exhibited better characteristics at a large current of 3 mA than the electricity storage device (B-2).
Thus, in the electricity storage devices (B-1) and (B-2), a high capacity can be obtained even when charging / discharging at a large current of 3 mA. This indicates that these electricity storage devices have a high capacity and output characteristics. Means excellent.
　各蓄電デバイスのインピーダンスを測定したところ、蓄電デバイス（Ｂ－３）の抵抗値は蓄電デバイス（Ｂ－１）の抵抗値よりも３０オームも大きい値であった。蓄電デバイス（Ｂ－１）は、負極以外は蓄電デバイス（Ｂ－３）と全く同じ構成であることから、負極の比表面積を大きくすることによって、蓄電デバイスのインピーダンスが低下することが確認された。 When the impedance of each power storage device was measured, the resistance value of the power storage device (B-3) was 30 ohms larger than the resistance value of the power storage device (B-1). Since the electricity storage device (B-1) has exactly the same configuration as the electricity storage device (B-3) except for the negative electrode, it was confirmed that the impedance of the electricity storage device is reduced by increasing the specific surface area of the negative electrode. .
　以上の結果から、材料あたりのエネルギー量が非常に大きい負極活物質である特定の非炭素材料を含み、かつ厚み１０μｍ以下の薄膜負極を用いる場合には、負極の比表面積は５以上が好ましいことがわかった。これにより、高容量で出力特性に優れた蓄電デバイス、すなわち高容量キャパシタが得られることがわかった。さらに、蓄電デバイスの出力特性が大幅に向上するため、負極の比表面積は１０以上がより好ましいことがわかった。 From the above results, the specific surface area of the negative electrode is preferably 5 or more when a specific non-carbon material which is a negative electrode active material having a very large energy amount per material is used and a thin film negative electrode having a thickness of 10 μm or less is used. I understood. As a result, it was found that an electricity storage device having a high capacity and excellent output characteristics, that is, a high-capacity capacitor was obtained. Furthermore, it was found that the specific surface area of the negative electrode is more preferably 10 or more because the output characteristics of the electricity storage device are greatly improved.
《実施例７》
　正極活物質に上記π共役ポリマーを用いた実施例３と同じ正極積層体を用いる以外、実施例６の蓄電デバイス（Ｂ－１）と同様に蓄電デバイス（Ｂ－４）を作製した。
　また、正極活物質に上記ラジカルポリマーを用いた実施例４と同じ正極積層体を用いる以外、実施例６の蓄電デバイス（Ｂ－１）と同様に蓄電デバイス（Ｂ－５）を作製した。 Example 7
An electricity storage device (B-4) was produced in the same manner as the electricity storage device (B-1) of Example 6, except that the same positive electrode laminate as in Example 3 using the π-conjugated polymer as the positive electrode active material was used.
Further, an electricity storage device (B-5) was produced in the same manner as the electricity storage device (B-1) of Example 6, except that the same positive electrode laminate as that of Example 4 using the above radical polymer as the positive electrode active material was used.
　蓄電デバイス（Ｂ－４）および（Ｂ－５）について、充放電容量評価を行った。充放電容量の評価は、充放電電流値４ｍＡ、充電上限電圧４．２Ｖ、放電下限電圧２．７５Ｖとし、充電休止時間および放電休止時間をそれぞれ１分として行った。充電休止時間とは、充電終了後、次の放電を開始するまでの時間である。この充放電を３回繰り返し、３回目の放電容量を充放電容量とした。
　得られた充放電容量は、蓄電デバイス（Ｂ－４）では０．１４ｍＡｈ、蓄電デバイス（Ｂ－５）では０．０８ｍＡｈであり、設計容量通りの高容量を得ることができた。すなわち、いずれの場合においても、正極活物質に活性炭を用いた場合と同様に、高容量を有し、かつ出力特性に優れる蓄電デバイスが得られた。また、正極活物質である酸化還元可能な有機化合物は、活性炭に比べて高容量であり、かつ高電圧での動作を可能にすることから、一層高容量で実用性に富む蓄電デバイスが得られた。 For the electricity storage devices (B-4) and (B-5), charge / discharge capacity evaluation was performed. The charge / discharge capacity was evaluated with a charge / discharge current value of 4 mA, a charge upper limit voltage of 4.2 V, a discharge lower limit voltage of 2.75 V, and a charge pause time and a discharge pause time of 1 minute each. The charging pause time is the time from the end of charging until the start of the next discharge. This charge / discharge was repeated three times, and the third discharge capacity was defined as the charge / discharge capacity.
The obtained charge / discharge capacity was 0.14 mAh in the electricity storage device (B-4) and 0.08 mAh in the electricity storage device (B-5), and a high capacity as designed was obtained. That is, in any case, as in the case of using activated carbon as the positive electrode active material, an electricity storage device having a high capacity and excellent output characteristics was obtained. In addition, the organic compound capable of oxidation and reduction, which is a positive electrode active material, has a higher capacity than activated carbon and enables operation at a higher voltage, so that an electric storage device with higher capacity and practicality can be obtained. It was.
《実施例８》
　本実施例では、蓄電デバイス構成時の負極のＳＯＣについて検討した。
　負極集電体に、銅箔（算術平均表面粗さＲａ＝２．０μｍ、厚み４３μｍ、比表面積１１．６）を用いた。電子線加熱蒸着法により、この銅箔上に珪素酸化物（ＳｉＯｘ）の薄膜からなる負極（厚み７μｍ、比表面積４．０）を形成した。このようにして、負極集電体および負極からなる負極積層体を得た。負極厚みの調整は蒸着時間を調整することで行った。電子線加熱蒸着の条件は次の通りである。蒸着源として、純度９９．９９９９％の珪素金属（（株）高純度化学研究所製）を用い、真空チャンバー内に純度９９．７％の酸素ガス（日本酸素（株）製）を導入して真空度３×１０－３Ｐａに調整した。また、蒸着源に照射する電子ビームの加速電圧を８ｋＶ、エミッションを５００ｍＡとした。負極形成後、蛍光Ｘ線分析により組成を分析した結果、負極中のＳｉとＯとの比はＳｉ：Ｏ＝１：０．６（モル比）であった。このことから、負極を構成する酸化珪素（ＳｉＯｘ）のｘの値は０．６であることが判った。 Example 8
In this example, the SOC of the negative electrode when the power storage device was configured was examined.
A copper foil (arithmetic average surface roughness Ra = 2.0 μm, thickness 43 μm, specific surface area 11.6) was used for the negative electrode current collector. A negative electrode (thickness 7 μm, specific surface area 4.0) made of a thin film of silicon oxide (SiOx) was formed on the copper foil by electron beam heating vapor deposition. Thus, the negative electrode laminated body which consists of a negative electrode collector and a negative electrode was obtained. The negative electrode thickness was adjusted by adjusting the deposition time. The conditions for electron beam heating vapor deposition are as follows. As a deposition source, silicon metal with a purity of 99.9999% (manufactured by Kojundo Chemical Laboratory Co., Ltd.) was used, and oxygen gas with a purity of 99.7% (manufactured by Nippon Oxygen Co., Ltd.) was introduced into the vacuum chamber. The degree of vacuum was adjusted to 3 × 10 −3 Pa. In addition, the acceleration voltage of the electron beam irradiated to the vapor deposition source was 8 kV, and the emission was 500 mA. As a result of analyzing the composition by fluorescent X-ray analysis after forming the negative electrode, the ratio of Si and O in the negative electrode was Si: O = 1: 0.6 (molar ratio). From this, it was found that the value of x of silicon oxide (SiOx) constituting the negative electrode was 0.6.
　次に、上記で得られた負極の容量を、以下のようにして確認した。上記と同じ方法で作製した負極積層体を、直径１３．５ｍｍの円盤状に打ち抜き裁断したものと、リチウム金属板（厚み３００μｍ）からなる対極とを、多孔質ポリエチレンシートからなるセパレータ（厚み２０μｍ）を介して対向配置してコイン型蓄電デバイスを作製した。この蓄電デバイスを３回充放電した。このとき、電流値０．５ｍＡ、上限電圧１．５Ｖ、および下限電圧０Ｖとした。この充放電により、充放電可能な可逆容量は２．１ｍＡｈ（単位面積あたりの負極容量：１．５ｍＡｈ／ｃｍ２）であり、充放電に寄与しない不可逆容量は０．５ｍＡｈであることを確認した。 Next, the capacity of the negative electrode obtained above was confirmed as follows. A separator (thickness 20 μm) made of a porous polyethylene sheet is formed by punching and cutting a negative electrode laminate produced by the same method as above into a disc shape having a diameter of 13.5 mm and a counter electrode made of a lithium metal plate (thickness 300 μm). A coin-type electricity storage device was manufactured by facing each other. This electricity storage device was charged and discharged three times. At this time, the current value was 0.5 mA, the upper limit voltage was 1.5 V, and the lower limit voltage was 0 V. By this charging / discharging, it was confirmed that the reversible capacity capable of charging / discharging was 2.1 mAh (negative electrode capacity per unit area: 1.5 mAh / cm 2 ), and the irreversible capacity not contributing to charging / discharging was 0.5 mAh. .
　本実施例では、負極に対して機械的充電を行い、ついで電気化学的充電により負極のＳＯＣを調整した。負極ＳＯＣは実施例１と同様の方法により求めた。
　具体的には、上記で得られた負極積層体における負極表面に、不可逆容量（０．６ｍＡｈ）に相当する厚み３μｍのリチウム金属層を蒸着法により形成した。なお、負極の表面に蒸着されたリチウム金属は、負極を電解質に浸漬しなくても負極に吸収され、負極において不可逆容量分が充電（リチウム充電）された。
　さらに、機械的充電後の負極積層体を直径１３．５ｍｍの円盤状に打ち抜き裁断したものと、リチウム金属板（厚み３００μｍ）からなる対極とを、セパレータを挟んで対向させてコイン型蓄電デバイスを作製した。 In this example, the negative electrode was mechanically charged, and then the SOC of the negative electrode was adjusted by electrochemical charging. The negative electrode SOC was determined by the same method as in Example 1.
Specifically, a lithium metal layer having a thickness of 3 μm corresponding to an irreversible capacity (0.6 mAh) was formed on the negative electrode surface of the negative electrode laminate obtained above by an evaporation method. The lithium metal deposited on the surface of the negative electrode was absorbed by the negative electrode without immersing the negative electrode in the electrolyte, and the irreversible capacity was charged (lithium charge) in the negative electrode.
Furthermore, a coin-type electricity storage device is obtained by making a negative electrode laminate after mechanical charging punched and cut into a disk shape having a diameter of 13.5 mm and a counter electrode made of a lithium metal plate (thickness 300 μm) with a separator interposed therebetween. Produced.
　そして、負極のＳＯＣが表５に示す値となるように、０．５ｍＡの定電流で所定時間充電した。具体的には、充電時間を調整して、負極のＳＯＣを２０％、４０％、５０％、７０％、８０％、９０％、０％、または１０％と変えて、それぞれ負極（Ｃ－１）～（Ｃ－８）を得た。なお、負極ＳＯＣを２０％、４０％、５０％、７０％、８０％、９０％、０％、または１０％とするための充電電気量は、それぞれ０．４２ｍＡｈ、０．８４ｍＡｈ、１．０５ｍＡｈ、１．４７ｍＡｈ、１．６８ｍＡｈ、１．８９ｍＡｈ、０ｍＡｈ、または０．２１ｍＡｈであった。また、上記ＳＯＣ調整後の負極（Ｃ－１）～（Ｃ－８）の厚みは、それぞれ６．８μｍ、７．６μｍ、８．１μｍ、８．７μｍ、９．２μｍ、９．６μｍ、６．０μｍ、および６．５μｍであり、いずれも１０μｍ以下であった。なお、セパレータおよび電解質には、実施例１の蓄電デバイスと同じものを用いた。 And it charged with the constant current of 0.5 mA for the predetermined time so that SOC of a negative electrode might become the value shown in Table 5. Specifically, by adjusting the charging time, the negative electrode SOC is changed to 20%, 40%, 50%, 70%, 80%, 90%, 0%, or 10%, respectively. ) To (C-8) were obtained. Note that the amount of charge to make the negative electrode SOC 20%, 40%, 50%, 70%, 80%, 90%, 0%, or 10% is 0.42 mAh, 0.84 mAh, and 1.05 mAh, respectively. 1.47 mAh, 1.68 mAh, 1.89 mAh, 0 mAh, or 0.21 mAh. The thicknesses of the negative electrodes (C-1) to (C-8) after the SOC adjustment are 6.8 μm, 7.6 μm, 8.1 μm, 8.7 μm, 9.2 μm, 9.6 μm, and 6. 0 μm and 6.5 μm, both of which were 10 μm or less. In addition, the same thing as the electrical storage device of Example 1 was used for the separator and the electrolyte.
　また、ＳＯＣの調整をしない（負極に対して機械的充電および電気化学的充電をしない）負極（厚み７μｍ）を含む負極積層体を用いた以外、実施例１と同様の方法により蓄電デバイス（Ｃ－９）を作製した。なお、この負極は、可逆容量の３０％に相当する不可逆容量分の充電処理を行っていないため、蓄電デバイス構成時の負極のＳＯＣを便宜上－３０％とした。
　上記負極積層体（Ｃ－１）～（Ｃ－９）を用いる以外、実施例１と同様の方法により、蓄電デバイス（Ｃ－１）～（Ｃ－９）を作製した。 In addition, an electricity storage device (C) was prepared in the same manner as in Example 1 except that a negative electrode laminate including a negative electrode (thickness: 7 μm) without adjusting SOC (not mechanically and electrochemically charged with respect to the negative electrode) was used. −9) was produced. Note that this negative electrode was not subjected to a charge process for an irreversible capacity corresponding to 30% of the reversible capacity, so the SOC of the negative electrode in the configuration of the electricity storage device was set to −30% for convenience.
Electric storage devices (C-1) to (C-9) were produced in the same manner as in Example 1, except that the negative electrode laminates (C-1) to (C-9) were used.
　蓄電デバイス（Ｃ－１）～（Ｃ－９）について、充放電容量の評価およびインピーダンス評価を行った。
　充放電容量の評価は、４ｍＡの電流値で定電流充放電を行い、充電上限電圧３．７５Ｖ、放電下限電圧２．７５Ｖとし、充電休止時間および放電休止時間をそれぞれ１分として行った。充電休止時間とは、充電終了後、次の放電を開始するまでの時間である。この充放電を３回繰り返し、３回目の放電容量を充放電容量とした。 The electricity storage devices (C-1) to (C-9) were evaluated for charge / discharge capacity and impedance.
The charge / discharge capacity was evaluated by performing constant current charge / discharge at a current value of 4 mA, a charge upper limit voltage of 3.75 V and a discharge lower limit voltage of 2.75 V, and a charge pause time and a discharge pause time of 1 minute each. The charging pause time is the time from the end of charging until the start of the next discharge. This charge / discharge was repeated three times, and the third discharge capacity was defined as the charge / discharge capacity.
　また、インピーダンス評価は、交流インピーダンス法を用い、充放電容量評価終了後の放電状態で行った。測定条件は、開回路電圧から振幅１０ｍＶ、周波数範囲１０６～０．１Ｈｚで行い、周波数１０Ｈｚのインピーダンス値を読み取った。
　なお、ここでいう蓄電デバイスのインピーダンスとは、蓄電デバイスの出力特性を知ることのできる指標である。たとえば蓄電デバイスのインピーダンスが小さい場合、蓄電デバイスは低抵抗であり、高出力特性を有することを意味し、インピーダンスが大きい場合、蓄電デバイスは高抵抗であり、高出力特性を有しないことを意味する。
　上記評価結果を表５に示す。なお、表５には、デバイス構成時（作製直後の放電時）の負極ＳＯＣ（％）、およびデバイス充電時の負極のＳＯＣ（％）も示す。 Moreover, impedance evaluation was performed in the discharge state after completion | finish of charging / discharging capacity | capacitance using the alternating current impedance method. Measurement conditions were an open circuit voltage with an amplitude of 10 mV and a frequency range of 10 6 to 0.1 Hz, and an impedance value at a frequency of 10 Hz was read.
Note that the impedance of the electricity storage device here is an index by which the output characteristics of the electricity storage device can be known. For example, when the impedance of the electricity storage device is small, it means that the electricity storage device has low resistance and high output characteristics, and when the impedance is large, it means that the electricity storage device has high resistance and does not have high output characteristics. .
The evaluation results are shown in Table 5. Table 5 also shows the negative electrode SOC (%) at the time of device configuration (during discharge immediately after fabrication) and the negative electrode SOC (%) at the time of device charging.
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　表５に示すように、蓄電デバイス（Ｃ－１）～（Ｃ－８）は、０．０８～０．１０ｍＡｈの充放電容量を示し、蓄電デバイスとしての動作を確認することができた。この蓄電デバイスの充放電時の電圧は２．７５～３．７５Ｖであり、およそ３Ｖ以上と、従来の電気二重層キャパシタに比べて高電圧が得られた。すなわち、高電圧で動作可能な、高容量を有する蓄電デバイスが得られた。
　蓄電デバイス（Ｃ－９）では充放電容量が得られなかったが、これは、負極の不可逆容量に起因すると思われる。つまり、作製直後の充電電気量の一部が、負極の不可逆容量として消費され、放電することができなかったためと思われる。なお、蓄電デバイス（Ｃ－１）～（Ｃ－８）では、いずれも負極のＳＯＣ調整過程において、負極の不可逆容量分を予め充電する処理を行ったため、良好な充放電容量が得られた。 As shown in Table 5, the electricity storage devices (C-1) to (C-8) exhibited a charge / discharge capacity of 0.08 to 0.10 mAh, and their operation as electricity storage devices could be confirmed. The voltage at the time of charging and discharging of this electricity storage device was 2.75 to 3.75 V, which was about 3 V or higher, which was higher than that of the conventional electric double layer capacitor. That is, an electricity storage device having a high capacity capable of operating at a high voltage was obtained.
The charge / discharge capacity could not be obtained with the electricity storage device (C-9), which is probably due to the irreversible capacity of the negative electrode. That is, it seems that part of the charged electricity immediately after the production was consumed as the irreversible capacity of the negative electrode and could not be discharged. In each of the electricity storage devices (C-1) to (C-8), a favorable charge / discharge capacity was obtained because the irreversible capacity of the negative electrode was charged in advance during the SOC adjustment process of the negative electrode.
　また、蓄電デバイスにおける負極の可逆容量が２．１ｍＡｈであったことから、負極活物質の利用率は４～５％、すなわち蓄電デバイスにおいて充電時と放電時の負極ＳＯＣの差は４～５％であった。このことから、蓄電デバイスに用いる負極ＳＯＣが０～９５％である場合に、動作電圧２．７５～３．７５Ｖと、およそ３Ｖ以上の電圧で動作する、高容量の蓄電デバイスが得られることがわかった。
　また、表５の結果より、蓄電デバイスのインピーダンスは負極のＳＯＣに大きく依存していることがわかった。充放電時の負極ＳＯＣが２０～９５％である蓄電デバイス（Ｃ－１）～（Ｃ－６）では、インピーダンスが６．２Ω以下に低下した。これに対して、負極のＳＯＣが２０％以下である蓄電デバイス（Ｃ－７）および（Ｃ－８）では、インピーダンスが１０Ω以上と増大した。この結果から、蓄電デバイスの負極のＳＯＣが２０～９５％である場合、インピーダンスが小さく、高出力な蓄電デバイスが得られることがわかった。なお、充放電容量の確認できなかった蓄電デバイス（Ｃ－９）に関しては、インピーダンス測定は行わなかった。 Further, since the reversible capacity of the negative electrode in the electricity storage device was 2.1 mAh, the utilization factor of the negative electrode active material was 4 to 5%, that is, the difference between the negative electrode SOC during charging and discharging in the electricity storage device was 4 to 5%. Met. From this, when the negative electrode SOC used for the electricity storage device is 0 to 95%, a high capacity electricity storage device that operates at an operating voltage of 2.75 to 3.75 V and approximately 3 V or more can be obtained. all right.
From the results in Table 5, it was found that the impedance of the electricity storage device greatly depends on the SOC of the negative electrode. In the electricity storage devices (C-1) to (C-6) in which the negative electrode SOC during charging / discharging was 20 to 95%, the impedance decreased to 6.2Ω or less. On the other hand, in the electricity storage devices (C-7) and (C-8) in which the SOC of the negative electrode was 20% or less, the impedance increased to 10Ω or more. From this result, it was found that when the SOC of the negative electrode of the electricity storage device is 20 to 95%, an electricity storage device with low impedance and high output can be obtained. The impedance measurement was not performed for the electricity storage device (C-9) for which the charge / discharge capacity could not be confirmed.
　次に、蓄電デバイス（Ｃ－１）、（Ｃ－３）、（Ｃ－６）、および（Ｃ－８）を用いて、充放電繰り返し試験を行った。充放電条件は、充放電電流４ｍＡ、充電上限電圧３．７５Ｖ、および放電下限電圧２．７５Ｖとした。また、充電終了後、次の放電を開始するまでの充電休止時間および、放電終了後、次の充電を開始するまでの放電休止時間は、それぞれ１分とした。このような充放電を５００回繰り返した。この充放電試験を６回、すなわち合計サイクル数が３０００回まで試験を繰り返した。
　上記の繰り返し試験において、充放電を５００回繰り返す毎に、充放電電流値を０．５ｍＡとした以外、上記と同様の条件で３回充放電を行い、３回目の放電容量を求めた。 Next, charge / discharge repetition tests were performed using the electricity storage devices (C-1), (C-3), (C-6), and (C-8). The charge / discharge conditions were a charge / discharge current of 4 mA, a charge upper limit voltage of 3.75 V, and a discharge lower limit voltage of 2.75 V. In addition, the charge pause time until the start of the next discharge after the end of the charge and the discharge pause time until the start of the next charge after the end of the discharge were each set to 1 minute. Such charging / discharging was repeated 500 times. This charge / discharge test was repeated 6 times, that is, until the total number of cycles was 3000.
In the above repeat test, every time charge / discharge was repeated 500 times, charge / discharge was performed three times under the same conditions as described above except that the charge / discharge current value was set to 0.5 mA, and the discharge capacity for the third time was obtained.
　この繰り返し試験の結果を図１７に示す。図１７中の容量維持率は、初回の放電容量に対する各サイクル時で求められた放電容量の比を百分率で表したものである。図１７から、蓄電デバイスの充放電繰り返し特性は、蓄電デバイスの負極ＳＯＣに大きく依存していることがわかった。具体的には、充放電時の負極ＳＯＣが２０～９５％の範囲内である蓄電デバイス（Ｃ－１）、（Ｃ－３）および（Ｃ－６）では、繰り返し回数が３０００回の時点で、容量維持率が５０％以上であるのに対し、充放電時の負極ＳＯＣが１０％である蓄電デバイス（Ｃ－８）では、繰り返し回数が３０００回の時点で、容量維持率が２０％に低下し、繰り返し特性が低下することがわかった。
　以上の結果から、高容量を有し、かつ出力特性および充放電繰り返し特性に優れた蓄電デバイスが得られるため、蓄電デバイスの充放電時における負極のＳＯＣは２０～９５％が好ましいことがわかった。 The results of this repeated test are shown in FIG. The capacity maintenance ratio in FIG. 17 represents the ratio of the discharge capacity obtained at each cycle to the initial discharge capacity in percentage. From FIG. 17, it was found that the charge / discharge repetition characteristics of the electricity storage device largely depended on the negative electrode SOC of the electricity storage device. Specifically, in the electricity storage devices (C-1), (C-3), and (C-6) in which the negative electrode SOC during charging / discharging is in the range of 20 to 95%, the number of repetitions is 3000 times. In the electricity storage device (C-8) in which the negative electrode SOC during charging / discharging is 10% while the capacity maintenance rate is 50% or more, the capacity maintenance rate is increased to 20% when the number of repetitions is 3000 times. It was found that the repetition characteristics deteriorated.
From the above results, it was found that the SOC of the negative electrode during charge / discharge of the electricity storage device is preferably 20 to 95% because an electricity storage device having a high capacity and excellent output characteristics and charge / discharge repetition characteristics can be obtained. .
《実施例９》
　正極活物質に上記π共役ポリマーを用いた実施例３と同じ正極積層体を用いる以外、実施例１１の蓄電デバイス（Ｃ－３）と同様にして、蓄電デバイス（Ｃ－１０）を作製した。
　また、正極活物質に上記ラジカルポリマーを用いた実施例４と同じ正極積層体を用いる以外、実施例１１の蓄電デバイス（Ｃ－３）と同様にして、蓄電デバイス（Ｃ－１１）を作製した。 Example 9
An electricity storage device (C-10) was produced in the same manner as the electricity storage device (C-3) of Example 11, except that the same positive electrode laminate as in Example 3 using the π-conjugated polymer as the positive electrode active material was used.
Further, a power storage device (C-11) was produced in the same manner as the power storage device (C-3) of Example 11 except that the same positive electrode laminate as that of Example 4 using the above radical polymer as the positive electrode active material was used. .
　蓄電デバイス（Ｃ－１０）および（Ｃ－１１）について、以下のように充放電容量評価を行った。充放電条件は、充放電電流値４ｍＡ、充電上限電圧４．２Ｖ、および放電下限電圧２．７５Ｖとし、充電終了後、次の放電を開始するまでの充電休止時間および、放電終了後、次の充電を開始するまでの放電休止時間は、それぞれ１分とした。この充放電を３回繰り返し、３回目の放電容量を充放電容量とした。その評価結果を蓄電デバイス（Ｃ－３）の結果とともに表６に示す。 The charge / discharge capacity of the electricity storage devices (C-10) and (C-11) was evaluated as follows. The charge / discharge conditions are a charge / discharge current value of 4 mA, a charge upper limit voltage of 4.2 V, and a discharge lower limit voltage of 2.75 V. After the end of charge, the charge rest time until the start of the next discharge, and after the end of discharge, The discharge pause time until the start of charging was 1 minute each. This charge / discharge was repeated three times, and the third discharge capacity was defined as the charge / discharge capacity. The evaluation results are shown in Table 6 together with the results of the electricity storage device (C-3).
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
　蓄電デバイス（Ｃ－１０）および（Ｃ－１１）では、蓄電デバイス（Ｃ－３）よりも高容量が得られた。これらの蓄電デバイスでは、充放電時の電圧が２．７５～４．２Ｖと、およそ３Ｖ以上であり、高電圧で動作することがわかった。
　蓄電デバイス（Ｃ－１０）および（Ｃ－１１）では、正極活物質に活性炭を用いた場合と同様に、高容量、かつ優れた出力特性および充放電繰り返し特性が得られた。なお、蓄電デバイス（Ｃ－１０）および（Ｃ－１１）では、負極ＳＯＣが５０～７０％の範囲で充放電を行ったが、負極ＳＯＣが２０～９５％の範囲内であれば、上記と同様の結果が得られる。 In the electricity storage devices (C-10) and (C-11), a higher capacity was obtained than in the electricity storage device (C-3). In these electricity storage devices, the voltage during charging and discharging was 2.75 to 4.2 V, approximately 3 V or more, and it was found that the device operates at a high voltage.
In the electricity storage devices (C-10) and (C-11), similar to the case where activated carbon was used as the positive electrode active material, high capacity and excellent output characteristics and charge / discharge repetition characteristics were obtained. In the electricity storage devices (C-10) and (C-11), the negative electrode SOC was charged / discharged in the range of 50 to 70%. If the negative electrode SOC was in the range of 20 to 95%, Similar results are obtained.
《実施例１０》
　本実施例では、負極集電体の形態について検討した。
　層状の負極集電体上に、電子線加熱蒸着法により、酸化珪素（ＳｉＯｘ）の薄膜からなる負極（厚み３．０μｍ）を形成した。負極厚みの調整は蒸着時間を調整することで行った。電子線加熱蒸着の条件は次の通りである。蒸着源として、純度９９．９９９９％の珪素金属（（株）高純度化学研究所製）を用い、真空チャンバー内に純度９９．７％の酸素ガス（日本酸素（株）製）を導入して真空度３×１０－３Ｐａに調整した。また、蒸着源に照射する電子ビームの加速電圧を８ｋＶ、エミッションを５００ｍＡとした。負極形成後、蛍光Ｘ線分析により組成を分析した結果、負極中のＳｉとＯとの比が、Ｓｉ：Ｏ＝１：０．６（モル比）であった。このことから、負極を構成する酸化珪素（ＳｉＯｘ）のｘの値は０．６であることが判った。 Example 10
In this example, the form of the negative electrode current collector was examined.
A negative electrode (thickness: 3.0 μm) made of a thin film of silicon oxide (SiOx) was formed on the layered negative electrode current collector by electron beam heating vapor deposition. The negative electrode thickness was adjusted by adjusting the deposition time. The conditions for electron beam heating vapor deposition are as follows. As a deposition source, silicon metal with a purity of 99.9999% (manufactured by Kojundo Chemical Laboratory Co., Ltd.) was used, and oxygen gas with a purity of 99.7% (manufactured by Nippon Oxygen Co., Ltd.) was introduced into the vacuum chamber The degree of vacuum was adjusted to 3 × 10 −3 Pa. In addition, the acceleration voltage of the electron beam irradiated to the vapor deposition source was 8 kV, and the emission was 500 mA. As a result of analyzing the composition by fluorescent X-ray analysis after forming the negative electrode, the ratio of Si and O in the negative electrode was Si: O = 1: 0.6 (molar ratio). From this, it was found that the value of x of silicon oxide (SiOx) constituting the negative electrode was 0.6.
　次に、上記で得られた負極の容量を、以下のようにして確認した。上記と同様にして作製された負極と、リチウム金属（厚み３００μｍ）である対極とを、多孔質ポリエチレンシートからなるセパレータ（厚み２０μｍ）を介して対向配置してコイン型蓄電デバイスを作製した。この蓄電デバイスを３回充放電した。このとき、電流値０．１ｍＡ、上限電圧１．５Ｖ、および下限電圧０Ｖとした。この充放電によれば、充放電可能な可逆容量は０．７２ｍＡｈ／ｃｍ２であり、充放電に寄与しない不可逆容量は０．２２ｍＡｈ／ｃｍ２であった。 Next, the capacity of the negative electrode obtained above was confirmed as follows. A negative electrode produced in the same manner as above and a counter electrode made of lithium metal (thickness: 300 μm) were arranged to face each other through a separator (thickness: 20 μm) made of a porous polyethylene sheet to produce a coin-type electricity storage device. This electricity storage device was charged and discharged three times. At this time, the current value was 0.1 mA, the upper limit voltage was 1.5V, and the lower limit voltage was 0V. According to this charging / discharging, the reversible capacity capable of charging / discharging was 0.72 mAh / cm 2 , and the irreversible capacity not contributing to charging / discharging was 0.22 mAh / cm 2 .
　上記で得られた負極は、作製直後の負極中の負極活物質がリチウムを含まないため、完全放電状態、すなわちＳＯＣが０％の状態である。負極のＳＯＣとは、蓄電デバイス全体としてではなく、負極単体の充電状態を表す指標であり、負極単体の満充電時の容量を１００％として、満充電量に対する充電量の割合を百分率で表した値である。したがって、完全に放電された状態のＳＯＣは０％であり、満充電状態のＳＯＣは１００％である。なお、負極活物質のＳＯＣは、以下の方法により求められる。リチウム基準で０～１．５Ｖの電位範囲において、負極容量に対して０．２ＣＡ（５時間率）で充電させた場合の負極の充電量をＳＯＣが１００％（満充電）であると定義し、この充電量を基準としてＳＯＣの値を求めることができる。 The negative electrode obtained above is in a completely discharged state, that is, in a state where the SOC is 0% because the negative electrode active material in the negative electrode immediately after production does not contain lithium. The SOC of the negative electrode is an index that represents the state of charge of the single negative electrode, not the entire power storage device, and represents the percentage of the charge amount with respect to the full charge amount as a percentage with the capacity when the negative electrode is fully charged being 100%. Value. Therefore, the fully discharged SOC is 0%, and the fully charged SOC is 100%. In addition, SOC of a negative electrode active material is calculated | required with the following method. In the potential range of 0 to 1.5V with respect to lithium, the charge amount of the negative electrode when charged at 0.2 CA (5-hour rate) with respect to the negative electrode capacity is defined as SOC of 100% (full charge). The SOC value can be obtained based on the charged amount.
　本実施例では、上記で得られた負極表面に厚み３．０μｍのリチウム金属層を蒸着法により形成して負極のＳＯＣを５０％に調整した。なお、負極の表面に蒸着されたリチウム金属は、負極を電解質に浸漬しなくても負極に吸収され、負極が充電（リチウム充電）される。また、このリチウム充電量は、負極の不可逆容量に加えて、ＳＯＣ５０％まで充電される充電電気量に相当する量である。このようにして得られたＳＯＣ５０％の負極は、４．５μｍの成膜厚みを有していた。 In this example, a 3.0 μm-thick lithium metal layer was formed on the negative electrode surface obtained above by an evaporation method, and the SOC of the negative electrode was adjusted to 50%. The lithium metal deposited on the surface of the negative electrode is absorbed by the negative electrode without being immersed in the electrolyte, and the negative electrode is charged (lithium charging). In addition to the irreversible capacity of the negative electrode, this lithium charge amount is an amount corresponding to the charge electricity amount charged to SOC 50%. The SOC 50% negative electrode thus obtained had a film thickness of 4.5 μm.
　上記の負極積層体を用いた以外、実施例１と同様の方法により蓄電デバイスを作製した。そして、上記の負極積層体作製時において、以下の各種負極集電体（Ｄ－１）～（Ｄ－７）を用いた。
　負極集電体（Ｄ－１）には、表面に突起を有する銅箔（比表面積１．４）を用いた。この負極集電体は、圧延銅箔をパターンめっきすることにより作製した。パターンめっきは、厚み２０μｍの圧延銅箔上にネガ型フォトレジストを塗布し、１０μｍ角のパターンが銅箔表面の９２％を占有するように配置されたネガ型マスクを用いて、銅箔上のレジストフィルムを露光、現像し、形成された溝に電解法により銅粒子を析出させ、その後レジストを除去し、台形形状を有する突起を表面に有する銅箔を得た。 An electricity storage device was produced in the same manner as in Example 1 except that the above negative electrode laminate was used. The following negative electrode current collectors (D-1) to (D-7) were used in the preparation of the negative electrode laminate.
As the negative electrode current collector (D-1), a copper foil having a protrusion on the surface (specific surface area 1.4) was used. This negative electrode current collector was produced by pattern plating of a rolled copper foil. Pattern plating is performed by applying a negative photoresist on a rolled copper foil having a thickness of 20 μm, and using a negative mask arranged so that a 10 μm square pattern occupies 92% of the copper foil surface. The resist film was exposed and developed, and copper particles were deposited in the formed grooves by an electrolytic method, and then the resist was removed to obtain a copper foil having protrusions having a trapezoidal shape on the surface.
　ここで、図１８は、負極集電体（Ｄ－１）である負極集電体７０の厚み方向断面における要部の走査型電子顕微鏡（ＳＥＭ）写真である。負極集電体７０は、圧延銅箔である集電膜７１と、集電膜７１の表面に形成される複数の突起７２とを含む。突起７２は、集電膜７１の厚み方向両面に形成した。突起７２の厚み方向断面形状は擬台形状であり、突起７２の高さは１５μｍであった。また、突起７２も含めた負極集電体７０の厚みは５０μｍ、突起７２の集電膜７１表面における占有面積は８％であり、負極集電体７０の占有体積に対する電解質保持部の容積比率は５５％であった。ここで、突起７２の占有面積とは、負極集電体７０表面の面積に対する、負極集電体７０表面における突起７２が形成された部分の総面積の割合である。
　突起７２の高さおよび負極集電体７０の厚みは集電体の断面電子顕微鏡観察により測定した。また、突起７２の集電体７１表面における占有面積は、集電体の表面電子顕微鏡観察により測定した。これらの値を用いて負極集電体７０の占有体積に対する電解質保持部の容積比率を計算により算出した。 Here, FIG. 18 is a scanning electron microscope (SEM) photograph of the main part in the cross section in the thickness direction of the negative electrode current collector 70 which is the negative electrode current collector (D-1). The negative electrode current collector 70 includes a current collector film 71 that is a rolled copper foil, and a plurality of protrusions 72 that are formed on the surface of the current collector film 71. The protrusions 72 were formed on both sides of the current collecting film 71 in the thickness direction. The cross-sectional shape in the thickness direction of the protrusion 72 was a pseudo trapezoid, and the height of the protrusion 72 was 15 μm. Further, the thickness of the negative electrode current collector 70 including the protrusions 72 is 50 μm, the occupied area of the protrusions 72 on the surface of the current collector film 71 is 8%, and the volume ratio of the electrolyte holding portion to the occupied volume of the negative electrode current collector 70 is 55%. Here, the occupation area of the protrusions 72 is the ratio of the total area of the portions where the protrusions 72 are formed on the surface of the negative electrode current collector 70 to the area of the surface of the negative electrode current collector 70.
The height of the protrusion 72 and the thickness of the negative electrode current collector 70 were measured by observing the current collector with a cross-sectional electron microscope. Further, the area occupied by the protrusion 72 on the surface of the current collector 71 was measured by observation of the current collector with a surface electron microscope. Using these values, the volume ratio of the electrolyte holding portion to the occupied volume of the negative electrode current collector 70 was calculated.
　負極集電体（Ｄ－２）には、厚み方向の両面に複数の突起を有する銅箔（比表面積１．４）を用いた。この負極集電体は圧延銅箔をパターンめっきすることにより作製した。パターンめっきは、厚み２０μｍの圧延銅箔上にネガ型フォトレジストを塗布し、１０μｍ角のパターンが銅箔表面の８５％を占有するように配置されたネガ型マスクを用いて、銅箔上のレジストフィルムを露光、現像し、形成された溝に電解法により銅粒子を析出させ、その後レジストを除去し、台形形状を有する突起を表面に有する銅箔を得た。突起の厚み方向断面形状は擬台形状であり、突起の高さは１５μｍであった。また、突起も含めた負極集電体の厚みは５０μｍ、突起の集電膜表面における占有面積は１５％であり、負極集電体の占有体積に対する電解質保持部の容積比率は５１％であった。 As the negative electrode current collector (D-2), a copper foil (specific surface area 1.4) having a plurality of protrusions on both surfaces in the thickness direction was used. This negative electrode current collector was produced by pattern plating of a rolled copper foil. Pattern plating is performed by applying a negative photoresist on a rolled copper foil having a thickness of 20 μm and using a negative mask arranged so that a 10 μm square pattern occupies 85% of the copper foil surface. The resist film was exposed and developed, and copper particles were deposited in the formed grooves by an electrolytic method, and then the resist was removed to obtain a copper foil having protrusions having a trapezoidal shape on the surface. The cross-sectional shape of the protrusion in the thickness direction was a pseudo trapezoid, and the height of the protrusion was 15 μm. The thickness of the negative electrode current collector including the protrusions was 50 μm, the area occupied by the protrusions on the surface of the current collector film was 15%, and the volume ratio of the electrolyte holding part to the volume occupied by the negative electrode current collector was 51%. .
　負極集電体（Ｄ－３）には、厚み方向の両面に複数の突起を有する銅箔（比表面積１．４）を用いた。この負極集電体は圧延銅箔をパターンめっきすることにより作製した。パターンめっきは、厚み１８μｍの圧延銅箔上にネガ型フォトレジストを塗布し、１０μｍ角のパターンが銅箔表面の８５％を占有するように配置されたネガ型マスクを用いて、銅箔上のレジストフィルムを露光、現像し、形成された溝に電解法により銅粒子を析出させ、その後レジストを除去し、台形形状を有する突起を表面に有する銅箔を得た。突起の厚み方向断面形状は擬台形状であり、突起の高さは１２μｍであった。また、突起も含めた負極集電体の厚みは４２μｍ、突起の集電膜表面における占有面積は１５％であり、負極集電体の占有体積に対する電解質保持部の容積比率は４９％であった。 As the negative electrode current collector (D-3), a copper foil (specific surface area 1.4) having a plurality of protrusions on both surfaces in the thickness direction was used. This negative electrode current collector was produced by pattern plating of a rolled copper foil. For pattern plating, a negative photoresist is applied on a rolled copper foil having a thickness of 18 μm, and a negative mask on which a 10 μm square pattern occupies 85% of the copper foil surface is used. The resist film was exposed and developed, and copper particles were deposited in the formed grooves by an electrolytic method, and then the resist was removed to obtain a copper foil having protrusions having a trapezoidal shape on the surface. The cross-sectional shape of the protrusion in the thickness direction was a pseudo trapezoid, and the height of the protrusion was 12 μm. The thickness of the negative electrode current collector including the protrusions was 42 μm, the area occupied by the protrusions on the surface of the current collector film was 15%, and the volume ratio of the electrolyte holding part to the volume occupied by the negative electrode current collector was 49%. .
　負極集電体（Ｄ－４）には、厚み方向の両面に複数の突起を有する銅箔（比表面積１．４）を用いた。この負極集電体は圧延銅箔をパターンめっきすることにより作製した。パターンめっきは、厚み２２μｍの圧延銅箔上にネガ型フォトレジストを塗布し、１０μｍ角のパターンが銅箔表面の９２％を占有するように配置されたネガ型マスクを用いて、銅箔上のレジストフィルムを露光、現像し、形成された溝に電解法により銅粒子を析出させ、その後レジストを除去し、台形形状を有する突起を表面に有する銅箔を得た。突起の厚み方向断面形状は擬台形状であり、突起の高さは１０μｍであった。また、突起も含めた負極集電体の厚みは４２μｍ、突起の集電膜表面における占有面積は８％であり、負極集電体の占有体積に対する電解質保持部の容積比率は４４％であった。 As the negative electrode current collector (D-4), a copper foil (specific surface area 1.4) having a plurality of protrusions on both surfaces in the thickness direction was used. This negative electrode current collector was produced by pattern plating of a rolled copper foil. Pattern plating is performed by applying a negative photoresist on a rolled copper foil having a thickness of 22 μm, and using a negative mask arranged so that a 10 μm square pattern occupies 92% of the copper foil surface. The resist film was exposed and developed, and copper particles were deposited in the formed grooves by an electrolytic method, and then the resist was removed to obtain a copper foil having protrusions having a trapezoidal shape on the surface. The cross-sectional shape of the protrusion in the thickness direction was a pseudo trapezoid, and the height of the protrusion was 10 μm. The thickness of the negative electrode current collector including the protrusions was 42 μm, the area occupied by the protrusions on the surface of the current collector film was 8%, and the volume ratio of the electrolyte holding portion to the volume occupied by the negative electrode current collector was 44%. .
　負極集電体（Ｄ－５）には、銅からなる発泡金属（厚み２００μｍ、平均孔径１００μｍ、気孔率（負極集電体占有体積に対する電解質保持部容積比率）８０％、三菱マテリアル（株）製）を用いた。 The negative electrode current collector (D-5) includes copper foam metal (thickness 200 μm, average pore diameter 100 μm, porosity (volume ratio of electrolyte holding portion to negative electrode current collector occupied volume) 80%, manufactured by Mitsubishi Materials Corporation. ) Was used.
　負極集電体（Ｄ－６）には、平滑な表面を有する圧延銅箔（算術平均表面粗さ（Ｒａ）０．１２μｍ、厚み２５μｍ、比表面積１．０）を用いた。ここで、図１９は、負極集電体（Ｄ－６）である負極集電体７５の厚み方向断面における要部の走査型電子顕微鏡（ＳＥＭ）写真である。負極集電体７５は、厚み方向表面に突起を有さず、また、厚み方向に貫通する貫通孔をも有さない。したがって、負極集電体７５の集電体占有体積に対する電解質保持部容積は０％である。なお、極集電体（Ｄ－６）を用いた場合の負極の比表面積は１．１であった。 As the negative electrode current collector (D-6), a rolled copper foil (arithmetic mean surface roughness (Ra) 0.12 μm, thickness 25 μm, specific surface area 1.0) having a smooth surface was used. Here, FIG. 19 is a scanning electron microscope (SEM) photograph of the main part in the cross section in the thickness direction of the negative electrode current collector 75 which is the negative electrode current collector (D-6). The negative electrode current collector 75 does not have a protrusion on the surface in the thickness direction and does not have a through hole penetrating in the thickness direction. Therefore, the electrolyte holding portion volume with respect to the current collector occupied volume of the negative electrode current collector 75 is 0%. When the electrode current collector (D-6) was used, the specific surface area of the negative electrode was 1.1.
　負極集電体（Ｄ－７）には、厚み方向の両面に複数の突起を有する銅箔（比表面積１．４）を用いた。この負極集電体は圧延銅箔をパターンめっきすることにより作製した。パターンめっきは、厚み２６μｍの圧延銅箔上にネガ型フォトレジストを塗布し、１０μｍ角のパターンが銅箔表面の７０％を占有するように配置されたネガ型マスクを用いて、銅箔上のレジストフィルムを露光、現像し、形成された溝に電解法により銅粒子を析出させ、その後レジストを除去し、台形形状を有する突起を表面に有する銅箔を得た。突起の厚み方向断面形状は擬台形状であり、突起の高さは８μｍであった。また、突起も含めた負極集電体の厚みは４２μｍ、突起の集電膜表面における占有面積は３０％であり、負極集電体の占有体積に対する電解質保持部の容積比率は２７％であった。
　上記負極集電体（Ｄ－１）～（Ｄ－７）を用いて、それぞれ蓄電デバイス（Ｄ－１）～（Ｄ－７）を作製した。 For the negative electrode current collector (D-7), a copper foil (specific surface area 1.4) having a plurality of protrusions on both surfaces in the thickness direction was used. This negative electrode current collector was produced by pattern plating of a rolled copper foil. For pattern plating, a negative photoresist is applied onto a rolled copper foil having a thickness of 26 μm, and a negative mask on which a 10 μm square pattern occupies 70% of the surface of the copper foil is used. The resist film was exposed and developed, and copper particles were deposited in the formed grooves by an electrolytic method, and then the resist was removed to obtain a copper foil having protrusions having a trapezoidal shape on the surface. The cross-sectional shape of the protrusion in the thickness direction was a pseudo trapezoid, and the height of the protrusion was 8 μm. The thickness of the negative electrode current collector including the protrusions was 42 μm, the area occupied by the protrusions on the surface of the current collector film was 30%, and the volume ratio of the electrolyte holding portion to the volume occupied by the negative electrode current collector was 27%. .
Using the negative electrode current collectors (D-1) to (D-7), power storage devices (D-1) to (D-7) were produced, respectively.
　蓄電デバイス（Ｄ－１）～（Ｄ－７）について、充放電容量評価を行った。なお、蓄電デバイス（Ｄ－１）～（Ｄ－７）は、正極容量が０．０８ｍＡｈであり、正極容量に対して十分過剰量の可逆容量を有する負極を用い、負極容量は正極容量よりも十分に大きい。したがって、これらの蓄電デバイスの理論充放電容量は０．０８ｍＡｈである。
　充放電容量の評価は、４ｍＡの定電流充放電で、充電上限電圧３．７５Ｖ、放電下限電圧２．７５Ｖとし、充電休止時間および放電休止時間をそれぞれ１分として行った。充電休止時間とは、充電終了後、次の放電を開始するまでの時間である。放電休止時間とは、放電終了後、次の充電を開始するまでの時間である。この充放電を３回繰り返し、３回目の放電容量を充放電容量とした。評価結果を表７に示す。なお、表７には、各蓄電デバイスにおける負極集電体の特性、負極集電体における突起高さまたは貫通孔径と負極成膜厚み（４．５μｍ）との比（突起高さ／負極成膜厚み、貫通孔径／負極成膜厚み）を併記する。 For the electricity storage devices (D-1) to (D-7), charge / discharge capacity evaluation was performed. The electricity storage devices (D-1) to (D-7) have a positive electrode capacity of 0.08 mAh, and use a negative electrode having a reversible capacity that is sufficiently excessive with respect to the positive electrode capacity. Big enough. Therefore, the theoretical charge / discharge capacity of these electricity storage devices is 0.08 mAh.
The charge / discharge capacity was evaluated by constant current charge / discharge of 4 mA, a charge upper limit voltage of 3.75 V and a discharge lower limit voltage of 2.75 V, and a charge pause time and a discharge pause time of 1 minute each. The charging pause time is the time from the end of charging until the start of the next discharge. The discharge pause time is the time from the end of discharge until the start of the next charge. This charge / discharge was repeated three times, and the third discharge capacity was defined as the charge / discharge capacity. Table 7 shows the evaluation results. Table 7 shows the characteristics of the negative electrode current collector in each power storage device, the ratio of the protrusion height or through-hole diameter in the negative electrode current collector to the negative electrode film formation thickness (4.5 μm) (projection height / negative electrode film formation). (Thickness, through-hole diameter / negative electrode film-forming thickness) are also shown.
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
　表面に突起を有する負極集電体を用いた蓄電デバイス（Ｄ－１）～（Ｄ－４）では、負極集電体の占有体積に対する電解質保持部の容積比率が４４～５５％と高く、負極集電体表面に電解質を保持できた。このため、蓄電デバイス（Ｄ－１）～（Ｄ－４）は、設計値通りの高容量の放電容量が得られた。
　厚み方向に貫通孔を有する多孔質膜からなる負極集電体（Ｄ－５）を用いた蓄電デバイス（Ｄ－５）においても、負極集電体による電解質保持効果が十分に発現され、高容量が得られた。負極集電体（Ｄ－５）は、表７中の各負極集電体のなかでも、負極集電体の占有体積に対する電解質保持部の容積比率（気孔率）が８０％と最も高く、電解質保持特性に最も優れていることがわかった。 In the electricity storage devices (D-1) to (D-4) using the negative electrode current collector having protrusions on the surface, the volume ratio of the electrolyte holding portion to the occupied volume of the negative electrode current collector is as high as 44 to 55%. The electrolyte could be retained on the current collector surface. For this reason, the storage devices (D-1) to (D-4) have a high discharge capacity as designed.
Also in the electricity storage device (D-5) using the negative electrode current collector (D-5) made of a porous film having through-holes in the thickness direction, the electrolyte retention effect by the negative electrode current collector is sufficiently exhibited, and the high capacity was gotten. The negative electrode current collector (D-5) has the highest volume ratio (porosity) of the electrolyte holding part to the occupied volume of the negative electrode current collector among the respective negative electrode current collectors in Table 7, and is the highest. It was found to have the best retention characteristics.
　平滑表面を有する無孔質銅箔を負極集電体として用いた蓄電デバイス（Ｄ－６）では、負極集電体による電解質保持効果がほぼ０であるため、放電容量が０．０５ｍＡｈと低下した。
　負極集電体（Ｄ－７）は、負極集電体（Ｄ－１）～（Ｄ－４）と比べて、負極集電体の占有体積に対する電解質保持部の容積比率が２７％と低く、突起高さが十分ではない（（突起高さ／負極成膜厚み）＝１．８）ため、電解質保持効果が十分に得られなかった。したがって、蓄電デバイス（Ｄ－７）では、蓄電デバイス（Ｄ－６）に比べて放電容量は若干改善されたが、蓄電デバイス（Ｄ－１）～（Ｄ－４）と比べて低い放電容量が得られた。
　以上のことから、蓄電デバイスの充放電特性が向上するため、電解質保持部の容積比率は３０％以上であるのが好ましいことがわかった。 In the electricity storage device (D-6) using a non-porous copper foil having a smooth surface as the negative electrode current collector, the discharge capacity was reduced to 0.05 mAh because the electrolyte retention effect by the negative electrode current collector was almost zero. .
In the negative electrode current collector (D-7), the volume ratio of the electrolyte holding part to the occupied volume of the negative electrode current collector is 27%, which is lower than the negative electrode current collectors (D-1) to (D-4). Since the protrusion height was not sufficient ((projection height / negative electrode film thickness) = 1.8), the electrolyte retention effect was not sufficiently obtained. Accordingly, the discharge capacity of the electricity storage device (D-7) is slightly improved compared to the electricity storage device (D-6), but the discharge capacity is lower than that of the electricity storage devices (D-1) to (D-4). Obtained.
From the above, it was found that the volume ratio of the electrolyte holding part is preferably 30% or more in order to improve the charge / discharge characteristics of the electricity storage device.
《実施例１１》
　正極活物質に上記π共役ポリマーを用いた実施例３と同じ正極積層体を用いる以外、実施例１０の蓄電デバイス（Ｄ－１）と同様にして、蓄電デバイス（Ｄ－８）を作製した。
　また、正極活物質に上記ラジカルポリマーを用いた実施例４と同じ正極積層体を用いる以外、実施例１０の蓄電デバイス（Ｄ－１）と同様にして、蓄電デバイス（Ｄ－９）を作製した。 Example 11
A power storage device (D-8) was produced in the same manner as the power storage device (D-1) of Example 10, except that the same positive electrode laminate as that of Example 3 using the π-conjugated polymer as the positive electrode active material was used.
Further, an electricity storage device (D-9) was produced in the same manner as the electricity storage device (D-1) of Example 10 except that the same positive electrode laminate as that of Example 4 using the radical polymer as a positive electrode active material was used. .
　蓄電デバイス（Ｄ－８）および（Ｄ－９）について、充放電容量評価を行った。充放電容量の評価は、充放電電流値４ｍＡ、充電上限電圧４．２Ｖ、および放電下限電圧２．７５Ｖとし、充電休止時間および放電休止時間をそれぞれ１分として行った。充電休止時間とは、充電終了後、次の放電を開始するまでの時間である。この充放電を３回繰り返し、３回目の放電容量を充放電容量とした。
　得られた充放電容量は、蓄電デバイス（Ｄ－８）では０．１４ｍＡｈ、蓄電デバイス（Ｄ－９）では０．０８ｍＡｈであり、設計容量通りの高容量を得ることができた。いずれの場合も、負極集電体の占有体積に対する電解質保持部の容積比率が５５％と高く、負極集電体に電解質を保持できた。 The electricity storage devices (D-8) and (D-9) were evaluated for charge / discharge capacity. The charge / discharge capacity was evaluated with a charge / discharge current value of 4 mA, a charge upper limit voltage of 4.2 V, and a discharge lower limit voltage of 2.75 V, and a charge pause time and a discharge pause time of 1 minute each. The charging pause time is the time from the end of charging until the start of the next discharge. This charge / discharge was repeated three times, and the third discharge capacity was defined as the charge / discharge capacity.
The obtained charge / discharge capacity was 0.14 mAh for the electricity storage device (D-8) and 0.08 mAh for the electricity storage device (D-9), and a high capacity as designed could be obtained. In either case, the volume ratio of the electrolyte holding part to the volume occupied by the negative electrode current collector was as high as 55%, and the electrolyte could be held in the negative electrode current collector.
　本発明の蓄電デバイスは、高出力、高容量および優れた充放電繰り返し特性を有するので、輸送機器、電気・電子機器などの電源、無停電電源などとして好適に使用できる。輸送機器には、たとえば、ハイブリッド自動車などが挙げられる。電気・電子機器には、たとえば、移動体通信機器、携帯機器などが挙げられる。 Since the electricity storage device of the present invention has high output, high capacity, and excellent charge / discharge repetition characteristics, it can be suitably used as a power source for transportation equipment, electrical / electronic equipment, and an uninterruptible power source. Examples of the transportation device include a hybrid vehicle. Examples of electric / electronic devices include mobile communication devices and portable devices.

Claims (25)

  1. 　正極集電体と、
    　前記正極集電体上に配された、少なくともアニオンを可逆的に吸脱着可能な正極活物質を含む正極と、
    　負極集電体と、
    　前記負極集電体上に配された、実質的に、リチウムイオンを可逆的に吸蔵および放出可能な負極活物質からなる負極と、を備え、
    　前記負極活物質は、珪素、珪素含有合金、珪素化合物、錫、錫含有合金および錫化合物からなる群より選ばれる少なくとも１つであり、
    　前記負極は厚み１０μｍ以下の薄膜であることを特徴とする蓄電デバイス。     A positive electrode current collector;
    A positive electrode including a positive electrode active material disposed on the positive electrode current collector and capable of reversibly absorbing and desorbing anions;
    A negative electrode current collector;
    A negative electrode made of a negative electrode active material, which is disposed on the negative electrode current collector and is substantially capable of reversibly occluding and releasing lithium ions,
    The negative electrode active material is at least one selected from the group consisting of silicon, a silicon-containing alloy, a silicon compound, tin, a tin-containing alloy, and a tin compound,
    The power storage device, wherein the negative electrode is a thin film having a thickness of 10 μm or less.
  2. 　前記負極の単位面積あたりの容量は、０．２～２．０ｍＡｈ/ｃｍ２である請求項１記載の蓄電デバイス。 The electric storage device according to claim 1, wherein the negative electrode has a capacity per unit area of 0.2 to 2.0 mAh / cm 2 .
  3. 　前記正極の厚みが、前記負極の厚みの５倍以上である請求項１記載の蓄電デバイス。 The electrical storage device according to claim 1, wherein the thickness of the positive electrode is 5 times or more the thickness of the negative electrode.
  4. 　前記負極の比表面積が、５以上である請求項１記載の蓄電デバイス。 The electric storage device according to claim 1, wherein the negative electrode has a specific surface area of 5 or more.
  5. 　前記負極集電体の比表面積が、５以上である請求項１記載の蓄電デバイス。 The electric storage device according to claim 1, wherein the negative electrode current collector has a specific surface area of 5 or more.
  6. 　前記負極集電体の表面粗さＲａの値が、前記負極の厚みと同じかまたはそれよりも大きい値である請求項１記載の蓄電デバイス。 The electric storage device according to claim 1, wherein the value of the surface roughness Ra of the negative electrode current collector is equal to or greater than the thickness of the negative electrode.
  7. 　前記負極活物質に予めリチウムが吸蔵されている請求項１記載の蓄電デバイス。 The electric storage device according to claim 1, wherein lithium is occluded in advance in the negative electrode active material.
  8. 　前記負極活物質へのリチウムの吸蔵が機械的に行われる請求項１記載の蓄電デバイス。 The electric storage device according to claim 1, wherein occlusion of lithium into the negative electrode active material is mechanically performed.
  9. 　前記蓄電デバイスの充放電時において、前記負極のＳＯＣが２０％以上９５％以下である請求項１記載の蓄電デバイス。 The power storage device according to claim 1, wherein the SOC of the negative electrode is 20% or more and 95% or less during charging / discharging of the power storage device.
  10. 　前記負極活物質が、珪素である請求項１記載の蓄電デバイス。 The electricity storage device according to claim 1, wherein the negative electrode active material is silicon.
  11. 　前記負極活物質が、珪素窒化物または珪素酸窒化物である請求項１記載の蓄電デバイス。 The electricity storage device according to claim 1, wherein the negative electrode active material is silicon nitride or silicon oxynitride.
  12. 　前記珪素化合物が、式ＳｉＯｘ（０＜ｘ＜２）で表される珪素酸化物である請求項１記載の蓄電デバイス。 The electric storage device according to claim 1, wherein the silicon compound is a silicon oxide represented by a formula SiOx (0 <x <2).
  13. 　前記正極活物質が活性炭である請求項１記載の蓄電デバイス。 The electric storage device according to claim 1, wherein the positive electrode active material is activated carbon.
  14. 　前記正極活物質が酸化還元可能な有機化合物である請求項１記載の蓄電デバイス。 The electricity storage device according to claim 1, wherein the positive electrode active material is an organic compound capable of oxidation and reduction.
  15. 　前記有機化合物は分子内にラジカルを有する請求項１４記載の蓄電デバイス。 The electric storage device according to claim 14, wherein the organic compound has a radical in the molecule.
  16. 　前記有機化合物は分子内にπ共役電子雲を有する請求項１４記載の蓄電デバイス。 The electricity storage device according to claim 14, wherein the organic compound has a π-conjugated electron cloud in the molecule.
  17. 　前記負極集電体は電解質保持部を有し、
    　前記電解質保持部の容積が前記負極集電体の占有体積の３０％以上である請求項１記載の蓄電デバイス。     The negative electrode current collector has an electrolyte holding part,
    The power storage device according to claim 1, wherein a volume of the electrolyte holding unit is 30% or more of a volume occupied by the negative electrode current collector.
  18. 　前記負極集電体は電解質保持部を有し、
    　前記電解質保持部の容積が前記負極集電体の占有体積の５０％以上である請求項１記載の蓄電デバイス。     The negative electrode current collector has an electrolyte holding part,
    The power storage device according to claim 1, wherein a volume of the electrolyte holding unit is 50% or more of a volume occupied by the negative electrode current collector.
  19. 　前記負極集電体が、厚み方向に貫通する複数の貫通孔を有する多孔質膜である請求項１記載の蓄電デバイス。 The electricity storage device according to claim 1, wherein the negative electrode current collector is a porous film having a plurality of through holes penetrating in the thickness direction.
  20. 　前記負極集電体が、厚み方向に貫通する貫通孔を有さずかつ表面に複数の突起を有し、
    　前記突起の前記負極集電体の厚み方向の断面形状が台形状または擬台形状である請求項１記載の蓄電デバイス。     The negative electrode current collector does not have a through-hole penetrating in the thickness direction and has a plurality of protrusions on the surface;
    The power storage device according to claim 1, wherein a cross-sectional shape of the protrusion in the thickness direction of the negative electrode current collector is trapezoidal or pseudo-trapezoidal.
  21. 　前記突起の高さが、前記負極の厚みの２倍以上である請求項２０記載の蓄電デバイス。 The electricity storage device according to claim 20, wherein the height of the protrusion is twice or more the thickness of the negative electrode.
  22. 　前記突起の先端部の少なくとも一部に、負極活物質を含む被覆層が形成されている請求項２０記載の蓄電デバイス。 21. The electricity storage device according to claim 20, wherein a coating layer containing a negative electrode active material is formed on at least a part of the tip of the protrusion.
  23. 　請求項１記載の蓄電デバイスを備えたノートＰＣ。 A notebook PC comprising the electricity storage device according to claim 1.
  24. 　請求項１記載の蓄電デバイスを備えたハイブリッド自動車。 A hybrid vehicle comprising the electricity storage device according to claim 1.
  25. 　請求項１記載の蓄電デバイスを備えた携帯電話。 A mobile phone comprising the electricity storage device according to claim 1.
PCT/JP2008/001275 2008-05-21 2008-05-21 Electrical storage device WO2009141850A1 (en)

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JP2022542586A (en) * 2019-07-29 2022-10-05 寧徳時代新能源科技股▲分▼有限公司 Silicon-oxygen compound, preparation method thereof, and related secondary battery, battery module, battery pack and device
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