WO2018025649A1 - All-solid-state lithium cell - Google Patents

All-solid-state lithium cell Download PDF

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Publication number
WO2018025649A1
WO2018025649A1 PCT/JP2017/026286 JP2017026286W WO2018025649A1 WO 2018025649 A1 WO2018025649 A1 WO 2018025649A1 JP 2017026286 W JP2017026286 W JP 2017026286W WO 2018025649 A1 WO2018025649 A1 WO 2018025649A1
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Prior art keywords
positive electrode
solid
oriented
electrode plate
lithium
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PCT/JP2017/026286
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French (fr)
Japanese (ja)
Inventor
雄樹 藤田
小林　伸行
幸信 由良
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日本碍子株式会社
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Priority to JP2018531828A priority Critical patent/JP6906524B2/en
Publication of WO2018025649A1 publication Critical patent/WO2018025649A1/en

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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0561—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of inorganic materials only
    • H01M10/0562—Solid materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0565—Polymeric materials, e.g. gel-type or solid-type
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H01M10/0585—Construction or manufacture of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/70—Carriers or collectors characterised by shape or form
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to an all solid lithium battery.
  • Patent Document 1 Japanese Patent No. 3427570
  • Patent Document 2 Japanese Patent No. 5775444 discloses a nonaqueous electrolyte battery electrode having a sheet-like conductive core material, a carbon layer, an active material layer, and a coating layer. It is disclosed that the material layer includes a ceramic film having a thickness of 20 to 120 ⁇ m formed of a sintered body of a transition metal oxide capable of occluding and / or releasing lithium.
  • Patent Document 3 Japanese Patent Laid-Open No. 2013-1057078 describes a positive electrode layer made of lithium cobaltate (LiCoO 2 ), a negative electrode layer made of metallic lithium, and a lithium phosphate oxynitride glass electrolyte (LiPON).
  • LiCoO 2 lithium cobaltate
  • LiPON lithium phosphate oxynitride glass electrolyte
  • a thin-film lithium secondary battery including a solid electrolyte layer that can be formed is disclosed, and it is described that a positive electrode layer is formed by sputtering and has a thickness in the range of 1 to 15 ⁇ m.
  • a thin film lithium secondary battery is manufactured by forming a positive electrode layer made of lithium cobaltate on a substrate, forming a solid electrolyte layer on the positive electrode layer, and forming metal lithium on the solid electrolyte layer. This is done by forming a negative electrode layer.
  • a positive electrode active material composed of a lithium composite oxide having a layered rock salt structure the diffusion of lithium ions (Li + ) therein is a plane parallel to the (003) plane (ie, the (003) plane).
  • lithium ions enter and exit in crystal planes other than the (003) plane (for example, (101) plane or (104) plane). Therefore, in this type of positive electrode active material, a surface that comes into contact with the electrolyte more in a crystal plane (a plane other than the (003) plane, for example, the (101) plane or the (104) plane) on which lithium ions can enter and exit satisfactorily. Attempts have been made to improve the battery characteristics of lithium secondary batteries by exposing them to the above.
  • Patent Document 4 (WO 2010/074304), a sheet containing Co 3 O 4 particles by firing a green sheet (h00) face is oriented parallel to the sheet surface including Co 3 O 4 It is disclosed that a LiCoO 2 ceramic sheet (positive electrode active material film) having a (104) plane oriented parallel to the sheet surface is produced by forming and then introducing Li.
  • the orientation direction of each primary particle exposed on the plate surface can be set to the [101] direction or the [104] direction. If the orientation direction of the primary particles is the [101] direction, the (003) plane of the primary particles is inclined by about 75 degrees with respect to the plate surface. If the orientation direction of the primary particles is the [104] direction, the (003) plane of the primary particles is inclined by about 48 degrees with respect to the plate surface.
  • the lithium composite oxide with a layered rock salt structure has the property that the interlayer distance increases as lithium ions are released. Dimension changes with. For this reason, tensile stress is generated with respect to the solid electrolyte layer, which may cause an electrical short circuit or an increase in resistance due to breakage or peeling of the solid electrolyte layer or generation of cracks.
  • stress is generated between the grains along with charge / discharge, which may cause deterioration of charge / discharge performance.
  • a conductive agent having a sufficiently low resistance in the in-plane direction is uniformly formed on the back surface of the positive electrode plate as a current collecting layer to enable uniform charge and discharge in the plate surface direction of the positive electrode plate. It is possible.
  • a metal film having a thickness of 10 ⁇ m or more is formed on the surface of the positive electrode plate by baking or the like, or a thickness of 5 ⁇ m or more is formed on the surface of the positive electrode plate.
  • a special configuration is required, such as bonding the metal foil (current collector foil) through a conductive adhesive.
  • the positive electrode plate expands and contracts due to charge / discharge, and the contact resistance increases due to deterioration factors such as interfacial peeling during use at a deep charge / discharge depth or for a long period of time. Invited, therefore, there was a problem with reliability.
  • a positive electrode plate made of a dense and thick ceramic sintered body is used as the positive electrode of the all-solid-state lithium battery, further improvement in long-term reliability is desired.
  • the object of the present invention is to improve the resistance increase rate during repeated use while adopting a thick positive electrode plate made of a sintered body, and therefore the long-term reliability is greatly improved.
  • the object is to provide an all-solid-state lithium battery having excellent battery characteristics.
  • a self-supporting oriented positive electrode plate having a thickness of 20 ⁇ m or more made of an oriented sintered body, wherein the oriented sintered body comprises a plurality of lithium composite oxides having a layered rock salt structure.
  • An oriented positive electrode plate comprising crystal grains, wherein the plurality of crystal grains have a (003) plane oriented parallel to a plate surface of the oriented positive electrode plate;
  • a solid electrolyte layer provided on the oriented positive electrode plate and made of a lithium ion conductive material;
  • a positive electrode current collector which is a metal foil having a thickness of 5 ⁇ m or more and 30 ⁇ m or less, which is in full contact with the surface opposite to the solid electrolyte layer of the oriented positive electrode plate in a non-adhesive state not containing an adhesive;
  • An all-solid lithium battery is provided.
  • FIG. 8 is a schematic cross-sectional view for conceptually explaining the lithium ion conduction direction and the expansion / contraction method in the oriented positive electrode plate used in the present invention as shown in FIG. 7. It is a SEM image which shows an example of a cross section perpendicular
  • FIG. 9B is an EBSD image of a cross section of the aligned positive electrode plate in a measurement region specified by a rectangular frame in FIG. 9A.
  • FIGS. 1 and 2 schematically show an example of an all solid lithium battery according to the present invention.
  • An all solid lithium battery 10 shown in FIGS. 1 and 2 includes an oriented positive electrode plate 12, a solid electrolyte layer 14, a negative electrode layer 16, and a positive electrode current collector 20.
  • An all-solid lithium battery 10 shown in FIG. 1 includes two unit batteries each composed of an oriented positive electrode plate 12, a solid electrolyte layer 14, a negative electrode layer 16, and a positive electrode current collector 20 via a negative electrode current collector 24. It has a configuration in which the layers are vertically stacked in parallel. However, the present invention is not limited to this, and may be configured by one unit cell 10 ′ as schematically shown in FIG.
  • the oriented positive electrode plate 12 is a self-supporting plate having a thickness of 20 ⁇ m or more made of an oriented sintered body, and the oriented sintered body includes a plurality of crystal grains composed of a lithium composite oxide having a layered rock salt structure. These crystal grains have a (003) plane oriented parallel to the plate surface of the oriented positive electrode plate 12.
  • the solid electrolyte layer 14 is provided on the oriented positive electrode plate 12 and is made of a lithium ion conductive material.
  • the negative electrode layer 16 is a layer provided on the solid electrolyte layer 14 and containing lithium.
  • the positive electrode current collector 20 is a metal foil having a thickness of 5 ⁇ m or more and 30 ⁇ m or less, and is in full contact with the surface opposite to the solid electrolyte layer 14 of the oriented positive electrode plate 12 in a non-adhesive state not containing an adhesive. Yes.
  • the alignment positive electrode plate is brought into full contact with a thin positive electrode current collector in a non-adhesive state without an adhesive. The rate of increase in resistance during repeated use can be significantly reduced, and as a result, long-term reliability can be greatly improved.
  • the positive electrode current collector 20 which is a metal foil having a thickness of 5 ⁇ m or more and 30 ⁇ m or less, is a flexible thin conductive material, and therefore can be uniformly adhered to the entire surface of the oriented positive electrode plate 12.
  • the positive electrode current collector 20 and the alignment positive electrode plate 12 which are metal foils are in point contact with each other microscopically, current collection unevenness may occur in the plane.
  • the distance between the contact points is significantly smaller than the thickness of the alignment positive electrode plate 12 (20 ⁇ m or more), unevenness of current collection due to misalignment from the contact point causes Li ion diffusion in the thickness direction of the alignment positive electrode plate 12. Therefore, uneven charging / discharging within the plate surface can be eliminated.
  • the aligned positive electrode plate 12 collects current with the positive electrode current collector 20 in an adhesive-free non-adhered state
  • the positive electrode current collector 20 does not basically follow even when the aligned positive electrode plate 12 expands and contracts. Even if this is not the case, since the positive electrode current collector 20 is a thin metal foil, it can follow expansion and contraction to some extent due to its ductility. In any case, the oriented positive electrode plate 12 can move relative to the positive electrode current collector 20 while ensuring contact with the positive electrode current collector 20 according to expansion and contraction. For this reason, the interface stress between the oriented positive electrode plate 12 and the positive electrode current collector 20 does not occur, and therefore, deterioration factors such as interface peeling can be eliminated.
  • long-term reliability is considered to be greatly improved. That is, interfacial peeling caused by expansion and contraction of the alignment positive electrode plate 12 due to charge and discharge and an increase in contact resistance caused thereby can be significantly suppressed, and long-term reliability can be improved.
  • battery characteristics such as rate characteristics and cycle characteristics are also improved by adopting an oriented positive plate whose (003) plane is oriented parallel to the plate surface of the oriented positive plate.
  • the positive current collector 20 is a metal foil.
  • the thickness of the metal foil is 5 to 30 ⁇ m, preferably 5 to 25 ⁇ m, more preferably 10 to 25 ⁇ m, and still more preferably 10 to 20 ⁇ m. By increasing the thickness as described above, a sufficient current collecting function can be ensured.
  • the positive electrode current collector 20 is entirely in contact with the surface of the oriented positive electrode plate 12 opposite to the solid electrolyte layer 14 in a non-adhesive state that does not contain an adhesive. For this reason, since it is rich in flexibility when it is a very thin metal foil as described above, it becomes easy to adhere to the entire surface of the alignment positive electrode plate 12 uniformly.
  • the metal constituting the positive electrode current collector 20 is not particularly limited as long as it does not react with the aligned positive electrode plate 12, and may be an alloy.
  • Preferred examples of such metals include stainless steel, aluminum, copper, platinum, and nickel, and more preferably stainless steel and nickel.
  • the positive electrode current collector 20 also serves as a positive electrode exterior material that covers the outer side of the aligned positive electrode plate 12.
  • the positive electrode current collector 20 also serves as a positive electrode exterior material that covers the outer side of the aligned positive electrode plate 12.
  • two unit cells are stacked in parallel symmetrically via a single negative electrode current collector 24 to expose the positive electrode current collector 20 to the outside of the all-solid-state lithium battery 10. It is good also as a structure.
  • the negative electrode current collector 24 can function as a current collector common to two adjacent unit batteries.
  • the positive electrode current collector 20 is preferably pressed against the aligned positive electrode plate 12. Since the metal foil which is the positive electrode current collector 20 is a flexible thin conductive material, a large number of contact points between the positive electrode current collector 20 and the alignment positive electrode plate 12 can be secured by pressing, and the alignment positive electrode plate 12 can be secured. Can be more uniformly adhered to the entire surface. Thereby, a desirable current collecting effect can be obtained while being in an adhesive-free non-adhered state.
  • the method of pressing is not particularly limited. For example, the pressing is performed from the outside of the positive electrode current collector 20 toward the alignment positive electrode plate 12 using a flexible pressing member (for example, foam metal) that does not damage the positive electrode current collector 20.
  • a method, a method using a pressure difference between the inside and outside of the positive electrode current collector 20, or the like can be employed.
  • the positive current collector 20 is pressed against the oriented positive electrode plate 12 due to a difference in internal and external pressures of the positive current collector 20. That is, it is only necessary that the orientation positive electrode plate 12 side of the positive electrode current collector 20 is depressurized or the side opposite to the orientation positive electrode plate 12 of the positive electrode current collector 20 is pressurized.
  • the metal foil as the positive electrode current collector 20 is a flexible thin conductive material according to the pressing using the internal and external pressure difference of the positive electrode current collector 20, the surface of the oriented positive electrode plate 12 Thus, the contact can be made at more contact points, and the current collecting effect can be further enhanced.
  • the positive electrode current collector 20 and the aligned positive electrode plate 12 are in a non-adhered state. This means that the positive electrode current collector 20 and the aligned positive electrode plate 12 are partially (for example, part of the outer peripheral portion of the aligned positive electrode plate 12) and are adhesive resins. It is not excluded that it is fixed by, for example. Such a resin is used for the purpose of temporary adhesion to prevent misalignment of the oriented positive electrode plate when assembling the battery.
  • the laminate including the oriented positive electrode plate 12, the solid electrolyte layer 14, and the negative electrode layer 16 is packaged or sealed with an exterior material.
  • the positive electrode current collector 20 constitutes a part of the exterior material, and the accommodation space of the laminate that is packaged or sealed with the exterior material is decompressed.
  • the storage space can be depressurized, for example, by packaging or sealing with an exterior material under reduced pressure, or by degassing the storage space after packaging or sealing the exterior material.
  • the metal foil that is the positive electrode current collector 20 is a flexible thin conductive material, the contact point of the positive electrode current collector 20 with the surface of the aligned positive electrode plate 12 is increased by reducing the storage space.
  • the degree of vacuum may be set as appropriate based on the flexibility of the metal and the strength of the laminate.
  • the positive electrode current collector 20 may include a carbon film on the surface on the solid electrolyte layer 14 side.
  • the thickness of the carbon film is preferably 0.01 ⁇ m to 5 ⁇ m, more preferably 0.01 ⁇ m to 1 ⁇ m, and still more preferably 0.05 ⁇ m to 0.5 ⁇ m.
  • the oriented positive electrode plate 12 is a self-supporting plate made of an oriented sintered body and having a thickness of 20 ⁇ m or more.
  • the oriented sintered body includes a plurality of crystal grains composed of a lithium composite oxide having a layered rock salt structure.
  • the lithium composite oxide is Li x MO 2 (0.05 ⁇ x ⁇ 1.10, M is at least one transition metal, and M is typically selected from Co, Ni, and Mn. Oxide containing a species or more).
  • the lithium composite oxide typically has a layered rock salt structure.
  • the layered rock salt structure is a crystal structure in which lithium layers and transition metal layers other than lithium are alternately stacked with oxygen layers in between, that is, the transition metal ion layers and lithium single layers are alternately arranged via oxide ions.
  • an ⁇ -NaFeO 2 type structure, ie a structure in which transition metals and lithium are regularly arranged in the [111] axis direction of a cubic rock salt type structure.
  • lithium composite oxides include lithium cobaltate, lithium nickelate, lithium manganate, nickel / lithium manganate, nickel / lithium cobaltate, cobalt / nickel / lithium manganate, cobalt / lithium manganate, etc. .
  • the lithium composite oxide includes Mg, Al, Si, Ca, Ti, V, Cr, Fe, Cu, Zn, Ga, Ge, Sr, Y, Zr, Nb, Mo, Ag, Sn, Sb, Te, Ba. , Bi, W, etc. may contain one or more elements.
  • a particularly preferable lithium composite oxide is lithium cobalt oxide. That is, it is particularly preferable that the crystal grains are lithium cobalt oxide crystal grains.
  • the (003) plane of the plurality of crystal grains contained in the oriented sintered body is oriented parallel to the plate surface of the oriented positive electrode plate. It is not necessary for all of the crystal grains contained in the oriented sintered body to be parallel, but most of them are preferably parallel.
  • “parallel” is not limited to perfect parallel (that is, 0 degree), but includes an angle equivalent to parallel, which should be substantially parallel.
  • the angle formed by the (003) plane is within 30 degrees, more typically within 25 degrees, even more typically within 20 degrees, particularly typically within 15 degrees, particularly typically within 10 degrees, most typically Specifically, it means within 5 degrees.
  • the layered rock salt structure lithium composite oxide has the property that the interlayer distance increases as lithium ions are released. That is, as conceptually shown in FIG.
  • the lithium composite oxide crystal grains 11 as primary particles have a lithium ion movement direction LiD parallel to the (003) plane, and the expansion / contraction direction perpendicular to the (003) plane.
  • LiD lithium ion movement direction
  • expansion / contraction direction perpendicular to the (003) plane.
  • ECD expansion / contraction direction
  • the oriented positive electrode plate 12 employed in the present invention has the (003) plane parallel to the plate surface as illustrated in the fracture surface SEM image of FIG. 7 and conceptually depicted in FIG.
  • the expansion in the surface direction of the aligned positive electrode plate 12 accompanying the release of lithium ions is reduced.
  • the tensile stress to the solid electrolyte layer 14 due to the expansion and contraction of the oriented positive electrode plate 12 at the time of charging / discharging is reduced, and an electrical short circuit or an increase in resistance due to the breakage or peeling of the solid electrolyte layer 14 or the occurrence of cracks is prevented. Can lead to improved cycle characteristics.
  • the angle of the crystal grain 11 is drawn larger than that shown in FIG. 7, but the crystal grain 11 is parallel to the same degree as in FIG. It should be understood as meaning.
  • the lithium ion moving distance is the same as that of the conventional aligned positive electrode plate 12 shown in FIG. It is much longer than the lithium ion movement distance. Nevertheless, battery characteristics such as rate characteristics and cycle characteristics are good, and this is a surprising finding that is totally unexpected.
  • FIG. 9A shows an SEM image showing an example of a cross section perpendicular to the plate surface of the oriented positive electrode plate
  • FIG. 9B shows an EBSD image of a cross section of the oriented positive electrode plate in the measurement region specified by the rectangular frame in FIG. 9A.
  • the orientation angle of each crystal grain is represented by color shading, and the darker the color, the smaller the orientation angle.
  • the orientation angle is an inclination angle formed by the (003) plane of each crystal grain with respect to the plate surface direction.
  • the portions displayed in black inside the oriented positive plate are pores.
  • the average value of the orientation angles of crystal grains (primary particles) (hereinafter referred to as “average orientation angle”) is more than 0 ° and not more than 30 °.
  • the average orientation angle of crystal grains or primary particles is obtained by arithmetically averaging the orientation angles of about 30 primary particles selected by the method described later in the EBSD image in the cross section of the orientation positive electrode plate as shown in FIG. 9B. can get.
  • the average orientation angle of the primary particles is preferably 30 ° or less and more preferably 25 ° or less in consideration of further improving the rate characteristics.
  • the average orientation angle of the primary particles is preferably 2 ° or more, more preferably 5 ° or more, considering rate characteristics.
  • the primary particles used for calculation of the average degree of orientation are those of the primary particles in the image when the observation magnification is set such that about 30 primary particles are included in the image in the EBSD image in the cross section of the positive electrode plate. All the particles whose outer periphery is completely included are included. Note that primary particles having a maximum ferret diameter of less than 0.5 ⁇ m are not counted.
  • the angle of the (003) plane with respect to the plate surface among the crystal grains included in the analyzed cross section exceeds 0 °.
  • the total area of crystal grains of 30 ° or less is 70% or more with respect to the total area of crystal grains included in the cross section. That is, in the EBSD image as shown in FIG. 9B, the total area of primary particles whose orientation angle is greater than 0 ° and 30 ° or less (hereinafter referred to as “low angle primary particles”) is used for calculating the average orientation angle.
  • the total area of the primary particles is preferably 70% or more.
  • the total area of the low-angle primary particles is preferably more than 70%, more preferably 80% with respect to the total area of about 30 primary particles used for calculating the average orientation angle.
  • the above is more preferable.
  • the total area of the low-angle primary particles having an orientation angle of 20 ° or less is more preferably 50% or more with respect to the total area of about 30 primary particles used for calculation of the average orientation angle. .
  • the total area of the low-angle primary particles having an orientation angle of 10 ° or less is more preferably 15% or more with respect to the total area of 30 primary particles used for calculating the average orientation angle.
  • the thickness of the alignment positive electrode plate 12 is preferably 20 ⁇ m or more, more preferably 30 ⁇ m or more, from the viewpoint of increasing the active material capacity per unit area and ensuring a self-supporting form free of a substrate. More preferably, it is 40 ⁇ m or more, particularly preferably 50 ⁇ m or more, and most preferably 55 ⁇ m or more.
  • the upper limit of the thickness is preferably 100 ⁇ m or less, more preferably 90 ⁇ m or less, still more preferably 80 ⁇ m or less, and particularly preferably from the viewpoint of reducing deterioration of battery characteristics (particularly increase in resistance value) due to repeated charge / discharge. 70 ⁇ m or less.
  • the size of the oriented positive electrode plate is preferably 5 mm ⁇ 5 mm square or more, more preferably 10 mm ⁇ 10 mm to 100 mm ⁇ 100 mm square, and further preferably 20 mm ⁇ 20 mm to 200 mm ⁇ 200 mm square. if, preferably 25 mm 2 or more, more preferably 100 ⁇ 10000 mm 2, more preferably from 400 ⁇ 40000 mm 2.
  • the crystal grains are preferably lithium cobaltate crystal grains.
  • LiCoO 2 constituting the lithium cobaltate crystal grains has a layered rock salt structure, but the oriented sintered plate used in the present invention is typically a plate in which the (003) plane of lithium cobaltate is an oriented positive plate. It is oriented parallel to the surface. This is because the ratio of the diffraction peak intensity due to the (003) plane to the diffraction peak intensity due to the (104) plane when taking the XRD profile of the plate surface is larger than that of the XRD profile of the pulverized powder. Can be judged.
  • the lithium cobalt oxide oriented sintered plate is Mg, Al, Si, Ca, Ti, V, Cr, Fe, Cu, Zn, Ga, Ge, Sr, Y, and the like within the scope of the present invention.
  • One or more elements such as Zr, Nb, Mo, Ag, Sn, Sb, Te, Ba, Bi, etc. are further doped or equivalent (for example, partial solid solution, segregation, coating, or adhesion to the surface layer of crystal grains) ) May contain a trace amount.
  • the density of the sintered body constituting the oriented positive electrode plate 12 is preferably 90% or more, more preferably 90 to 98%, still more preferably 92 to 98%, and particularly preferably 92 to 95%.
  • the density can be calculated by measuring the bulk density of the sintered body by the Archimedes method and dividing the bulk density by the true density. Alternatively, the density may be calculated by performing SEM observation at 1000 magnifications after CP polishing of the cross section of the aligned positive electrode plate 12, and binarizing the obtained SEM image. From the viewpoint of capacity and energy density, it is basically desirable that the density be high, but if it is within the above range, the resistance value is unlikely to increase even after repeated charge and discharge. It is considered that this is because the dense positive electrode plate 12 can be appropriately expanded and contracted as lithium is deinserted and the stress can be relaxed.
  • the oriented positive electrode plate 12 is preferably provided with a conductive film 12a having a thickness of 0.01 ⁇ m or more and less than 5 ⁇ m on the surface opposite to the solid electrolyte layer 14 (surface on the positive electrode current collector 20 side).
  • the conductive film 12a is preferably made of metal and / or carbon. When the conductive film 12a is made of a metal, the conductive film 12a has a low electron conduction resistance with the positive electrode current collector 20 and the alignment positive electrode plate 12 and is a layer made of a metal that does not adversely affect the characteristics of the alignment positive electrode plate 12, in particular.
  • preferred examples include an Au sputtered layer and a Si sputtered layer.
  • a carbon layer may be used instead of a metal conductive film such as an Au sputter layer.
  • the thickness of the conductive film 12a is 0.01 ⁇ m or more and less than 5 ⁇ m, preferably 0.02 ⁇ m or more and 2 ⁇ m or less, more preferably 0.02 ⁇ m or more and 1 ⁇ m or less, and further preferably 0.04 ⁇ m or more and 1 ⁇ m or less.
  • the lithium ion conductive material constituting the solid electrolyte layer 14 is a garnet ceramic material, a nitride ceramic material, a perovskite ceramic material, a phosphate ceramic material, a sulfide ceramic material, or a polymer material.
  • it is at least one selected from the group consisting of garnet-based ceramic materials, nitride-based ceramic materials, perovskite-based ceramic materials, and phosphate-based ceramic materials.
  • garnet based ceramic materials include Li—La—Zr—O based materials (specifically, Li 7 La 3 Zr 2 O 12 etc.), Li—La—Ta—O based materials (specifically, Li 7 La 3 Ta 2 O 12 etc.).
  • nitride ceramic material is Li 3 N.
  • perovskite ceramic materials include Li—La—Zr—O based materials (specifically, LiLa 1-x Ti x O 3 (0.04 ⁇ x ⁇ 0.14), etc.).
  • phosphate ceramic materials include lithium phosphate, nitrogen-substituted lithium phosphate (LiPON), Li—Al—Ti—PO, Li—Al—Ge—PO, and Li—Al—Ti—.
  • Si—P—O specifically, Li 1 + x + y Al x Ti 2 ⁇ x Si y P 3 ⁇ y O 12 (0 ⁇ x ⁇ 0.4, 0 ⁇ y ⁇ 0.6), etc. may be mentioned.
  • the lithium ion conductive material constituting the solid electrolyte layer 14 is composed of a Li—La—Zr—O based ceramic material and / or a lithium phosphate oxynitride (LiPON) based ceramic material.
  • the Li—La—Zr—O-based material is an oxide sintered body having a garnet-type or garnet-type similar crystal structure including Li, La, Zr, and O. Specifically, Li 7 A garnet-based ceramic material such as La 3 Zr 2 O 12 .
  • the garnet-based ceramic material is a lithium ion conductive material that does not react even when directly contacted with the negative electrode lithium, and in particular, a garnet-type or garnet-type similar crystal structure including Li, La, Zr, and O Oxide sintered bodies having excellent sinterability and easy densification and high ionic conductivity.
  • a garnet-type or garnet-like crystal structure having this kind of composition is called an LLZ crystal structure, which is referred to as CSD (Cambridge Structure Database) X-ray diffraction file No. It has an XRD pattern similar to 422259 (Li 7 La 3 Zr 2 O 12 ). In addition, No.
  • the constituent elements are different and the Li concentration in the ceramics may be different, so the diffraction angle and the diffraction intensity ratio may be different.
  • the molar ratio Li / La of Li to La is preferably 2.0 or more and 2.5 or less, and the molar ratio Zr / La to La is preferably 0.5 or more and 0.67 or less.
  • This garnet-type or garnet-like crystal structure may further comprise Nb and / or Ta. That is, by replacing a part of Zr of LLZ with one or both of Nb and Ta, the conductivity can be improved as compared with that before the substitution.
  • the substitution amount (molar ratio) of Zr with Nb and / or Ta is preferably set such that the molar ratio of (Nb + Ta) / La is 0.03 or more and 0.20 or less.
  • the garnet-based oxide sintered body preferably further contains Al, and these elements may exist in the crystal lattice or may exist in other than the crystal lattice.
  • the amount of Al added is preferably 0.01 to 1% by mass of the sintered body, and the molar ratio Al / La to La is preferably 0.008 to 0.12.
  • Such LLZ-based ceramics can be manufactured according to a known method or by appropriately modifying it.
  • a lithium phosphate oxynitride (LiPON) ceramic material is also preferable.
  • LiPON is a group of compounds represented by the composition of Li 2.9 PO 3.3 N 0.46 .
  • Li a PO b N c (wherein a is 2 to 4 and b is 3 to 5 , C is 0.1 to 0.9).
  • the dimensions of the solid electrolyte layer 14 are not particularly limited, but the thickness is preferably 0.0005 mm to 0.1 mm, more preferably 0.001 mm to 0.05 mm, and still more preferably, from the viewpoint of charge / discharge rate characteristics and mechanical strength. Is 0.002 to 0.02 mm, particularly preferably 0.003 to 0.01 mm.
  • various particle jet coating methods, solid phase methods, solution methods, and gas phase methods can be used.
  • the particle jet coating method include an aerosol deposition (AD) method, a gas deposition (GD) method, a powder jet deposition (PJD) method, a cold spray (CS) method, and a thermal spraying method.
  • the aerosol deposition (AD) method is particularly preferable because it can form a film at room temperature, and does not cause a composition shift in the process or formation of a high resistance layer by reaction with an oriented positive electrode plate.
  • the solid phase method include a tape lamination method and a printing method.
  • the tape lamination method is preferable because the solid electrolyte layer 14 can be formed thin and the thickness can be easily controlled.
  • the solution method include a solvothermal method, a hydrothermal synthesis method, a sol-gel method, a precipitation method, a microemulsion method, and a solvent evaporation method.
  • the hydrothermal synthesis method is particularly preferable in that it is easy to obtain crystal grains having high crystallinity at a low temperature.
  • microcrystals synthesized using these methods may be deposited on the positive electrode or may be directly deposited on the positive electrode.
  • gas phase method examples include laser deposition (PLD) method, sputtering method, evaporation condensation (PVD) method, gas phase reaction method (CVD) method, vacuum deposition method, molecular beam epitaxy (MBE) method and the like.
  • PLD laser deposition
  • PVD evaporation condensation
  • CVD gas phase reaction method
  • MBE molecular beam epitaxy
  • the sputtering method is particularly preferable because there is little composition deviation and a film with relatively high adhesion can be easily obtained.
  • the interface between the oriented positive electrode plate 12 and the solid electrolyte layer 14 may be subjected to a treatment for reducing the interface resistance.
  • a treatment for reducing the interface resistance includes niobium oxide, titanium oxide, tungsten oxide, tantalum oxide, lithium-nickel composite oxide, lithium-titanium composite oxide, lithium-niobium compound, lithium-tantalum compound, lithium-
  • This can be done by coating the surface of the oriented positive electrode plate 12 and / or the surface of the solid electrolyte layer 14 with a tungsten compound, a lithium / titanium compound, and any combination or composite oxide thereof.
  • a coating film can exist at the interface between the oriented positive electrode plate 12 and the solid electrolyte layer 14, but the thickness of the coating film is extremely thin, for example, 20 nm or less.
  • Negative electrode layer The negative electrode layer 16 is a layer containing lithium and is typically composed of lithium metal.
  • the negative electrode layer 16 may be formed by placing lithium metal in the form of a foil on the solid electrolyte layer 14 or the negative electrode current collector 24, or may be formed on the solid electrolyte layer 14 or the negative electrode current collector 24.
  • the thin film can be formed by a vacuum deposition method, a sputtering method, a CVD method, or the like to form a lithium metal layer.
  • the dimensions of the negative electrode layer 16 are not particularly limited, but the thickness is preferably 10 ⁇ m or more, more preferably 50 to 10 ⁇ m, from the viewpoint of securing a large amount of lithium in the all-solid lithium battery 10 with the adoption of the thick oriented positive electrode plate 12. More preferably, it is 40 to 10 ⁇ m, particularly preferably 20 to 10 ⁇ m.
  • an intermediate layer may be interposed between the negative electrode layer 16 and the solid electrolyte layer 14. That is, the all-solid-state lithium battery 10 can further include an intermediate layer containing a metal that can be alloyed with lithium on the surface of the solid electrolyte layer 14 on the negative electrode layer 16 side.
  • a metal alloyed with lithium, an oxide-based material, or the like can be used as a constituent material of the intermediate layer. In this way, even when subjected to a process involving heating such as a reflow soldering process (for example, a process performed at a temperature of 200 ° C. or higher), the melting of lithium metal and the like is significantly suppressed, and therefore an internal short circuit And peeling of the negative electrode layer can be effectively prevented.
  • Metals that can be alloyed with lithium are Al (aluminum), Si (silicon), Zn (zinc), Ga (gallium), Ge (germanium), Ag (silver), Au (gold), Pt (platinum), Cd. It is preferable to include at least one selected from the group consisting of (cadmium), In (indium), Sn (tin), Sb (antimony), Pb (lead), and Bi (bismuth), and more preferably Au ( It contains at least one selected from the group consisting of gold), In (indium), Si (silicon), Sn (tin), Zn (zinc), and Al (aluminum).
  • a preferable metal alloyable with lithium may include at least one selected from Au (gold) and In (indium).
  • the metal that can be alloyed with lithium may be an alloy composed of two or more elements such as Mg 2 Si and Mg 2 Sn.
  • the oxide material include Li 4 Ti 5 O 12 , TiO 2 , and SiO.
  • the intermediate layer may be formed by a known method such as an aerosol deposition (AD) method, a pulse laser deposition (PLD) method, a sputtering method, or an evaporation method.
  • the dimension of the intermediate layer is not particularly limited, but the thickness is preferably 0.05 to 1 ⁇ m, more preferably 0.05 to 0.5 ⁇ m, and still more preferably 0.08, from the viewpoint of promoting alloying during heating.
  • the thickness is from 0.2 to 0.2 ⁇ m, particularly preferably from 0.1 to 0.15 ⁇ m.
  • middle layer since the material illustrated as an intermediate
  • the end insulating portion 18 may be provided so as to insulate the end portion of the solid electrolyte layer 14.
  • the end insulating portion 18 preferably includes an organic polymer material that can be adhered or adhered to the solid electrolyte layer 14.
  • the organic polymer material is preferably at least one selected from the group consisting of a binder, a hot melt resin, and an adhesive.
  • the binder include a cellulose resin, an acrylic resin, and a combination thereof.
  • the heat fusion resin include a fluorine resin, a polyolefin resin, and any combination thereof.
  • the hot-melt resin is preferably provided in the form of a heat-sealing film as will be described later.
  • a preferable example of the adhesive is a thermosetting adhesive using a thermosetting resin such as an epoxy resin. Accordingly, it can be said that the organic polymer material is preferably at least one selected from the group consisting of a cellulose resin, an acrylic resin, a fluorine resin, a polyolefin resin, and an epoxy resin.
  • Examples of the cellulose resin include carboxymethyl cellulose, carboxyethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, cellulose butyrate, cellulose acetate butyrate, and the alkali metal salts and ammonium salts described above.
  • Examples of the acrylic resin include polyacrylic acid esters, polyacrylic acid salts, and maleic anhydride modified products, maleic acid modified products and fumaric acid modified products thereof.
  • fluororesins examples include polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP). ), Polychlorotrifluoroethylene (PCTFE), tetrafluoroethylene / hexafluoropropylene / vinylidene fluoride copolymer, hexafluoropropylene / vinylidene fluoride copolymer, and maleic anhydride-modified products thereof, maleic acid Examples include modified products and fumaric acid modified products. Examples of the polyolefin-based resin include polyethylene, polypropylene, cycloolefin polymer, and maleic anhydride modified products, maleic acid modified products and fumaric acid modified products thereof.
  • the end insulating portion 18 is preferably formed by applying a liquid or slurry containing an organic polymer material (preferably a binder) and optionally a filler or the like.
  • a liquid or slurry application method include a dispensing method, a screen printing method, a spray method, a stamping method, and the like.
  • the negative electrode current collector 24 is preferably provided outside the negative electrode current collector negative electrode layer 16.
  • the negative electrode current collector 24 may also serve as a negative electrode exterior material that covers the outside of the negative electrode.
  • two unit cells are stacked vertically and symmetrically via one positive current collector 20 to form a negative current collector 24. May be exposed to the outside of the all-solid-state lithium battery.
  • the positive electrode current collector 20 can function as a current collector common to two adjacent unit batteries.
  • the negative electrode current collector 24 may be made of the same or different material as the positive electrode current collector 20, but is preferably made of the same kind of material.
  • the metal constituting the negative electrode current collector 24 is not particularly limited as long as it does not react with the negative electrode layer 16 and may be an alloy. Preferred examples of such metals include stainless steel, aluminum, copper, platinum, and nickel, and more preferably stainless steel.
  • the negative electrode current collector 24 is preferably a metal plate or a metal foil, and more preferably a metal foil. Therefore, it can be said that the most preferred current collector is a stainless steel foil.
  • the preferred thickness of the metal foil is 1 to 30 ⁇ m, more preferably 5 to 25 ⁇ m, and still more preferably 10 to 20 ⁇ m.
  • the end-sealing portion all solid lithium battery 10 is not coated with the positive electrode current collector 20 and the negative electrode current collector 24, and is aligned with the positive electrode plate 12, the solid electrolyte layer 14, the negative electrode layer 16, and (if present) It is preferable that an end sealing portion 26 made of a sealing material for sealing the exposed portion of the end insulating portion 18 is further provided. An end sealing portion 26 is provided to expose exposed portions of the oriented positive electrode plate 12, the solid electrolyte layer 14, the negative electrode layer 16, and the end insulating portion 18 that are not covered with the positive electrode current collector 20 and the negative electrode current collector 24. By sealing, excellent moisture resistance (desirably moisture resistance at high temperature) can be ensured.
  • the end sealing portion 26 is made of a sealing material.
  • the sealing material can seal the exposed portion not covered with the positive electrode current collector 20, the negative electrode current collector 24, and the end insulating portion 18 to ensure excellent moisture resistance (preferably moisture resistance at high temperature). If it is a thing, it will not specifically limit. However, it goes without saying that it is desirable that the sealing material ensure electrical insulation between the positive electrode current collector 20 and the negative electrode current collector 24.
  • the sealing material preferably has a resistivity of 1 ⁇ 10 6 ⁇ cm or more, more preferably 1 ⁇ 10 7 ⁇ cm or more, and further preferably 1 ⁇ 10 8 ⁇ cm or more. Such a resistivity can significantly reduce self-discharge.
  • the thickness of the end sealing portion 26 is preferably 10 to 300 ⁇ m, more preferably 15 to 200 ⁇ m, still more preferably 20 to 150 ⁇ m.
  • the intrusion of moisture into the battery can only occur through the end sealing portion 26. This is because moisture is not transmitted when the positive electrode current collector and the negative electrode current collector are made of metal. Therefore, the thinner the end sealing portion 26 (that is, the narrower the entrance of moisture intrusion) is, and the greater the width of the end sealing portion (ie, the longer the path of moisture intrusion), the more the device enters the battery.
  • the amount of moisture is reduced, that is, moisture resistance is improved. From such a viewpoint, it can be said that the thickness within the above range is preferable.
  • the width of the end sealing portion 26 (also referred to as the thickness of the solid electrolyte layer 14 in the layer surface direction) is preferably 0.5 to 3 mm, more preferably 0.7 to 2 mm, and further preferably 1 to 2 mm. It is. When the width is within the above range, the end sealing portion 26 does not become too large, so that the volume energy density of the battery can be secured high.
  • the sealing material is preferably a resin-based sealing material containing a resin.
  • the end sealing portion 26 can be formed at a relatively low temperature (for example, 400 ° C. or lower), and as a result, battery destruction and alteration due to sealing accompanied by heating can be effectively prevented. be able to.
  • the resin preferably has a thermal expansion coefficient of 7 ⁇ 10 ⁇ 6 / ° C. or more, more preferably 9 ⁇ 10 ⁇ 6 to 20 ⁇ 10 ⁇ 6 / ° C., and still more preferably 10 ⁇ 10 ⁇ 6 to 19 ⁇ 10 ⁇ .
  • the resin is preferably an insulating resin.
  • the insulating resin is preferably a resin (adhesive resin that can be bonded with heat, an adhesive, or the like) that can be bonded while maintaining insulating properties.
  • preferable insulating resins include olefin resins, fluorine resins, acrylic resins, epoxy resins, urethane resins, and silicon resins.
  • particularly preferable resins include, as a low moisture-permeable resin sealing material, polypropylene (PP), polyethylene (PE), cycloolefin polymer, and polychlorotrifluoroethylene (PCTFE), and modified maleic anhydrides thereof, Examples thereof include an adhesive resin having a low water permeability and a heat fusion type typified by a maleic acid modified product and a fumaric acid modified product.
  • the insulating resin can be composed of at least one or a plurality of types of laminates. Further, a thermoplastic resin molded sheet or a resin having a reactive adhesive component may be used as at least one kind of insulating resin.
  • the resin-based sealing material may be made of a mixture of a resin (preferably an insulating resin) and an inorganic material.
  • a resin preferably an insulating resin
  • inorganic materials include silica, alumina, zinc oxide, magnesia, calcium carbonate, calcium hydroxide, barium sulfate, mica and talc, and silica is more preferable.
  • a resin-based sealing material made of a mixture of an epoxy resin and silica is preferably exemplified.
  • the end sealing portion 26 may be formed by laminating a resin film on the positive electrode current collector (thermal fusion or bonding via an adhesive), dispensing a liquid resin, or the like. It is preferable that gaps that can be formed between the end side surfaces of the alignment positive electrode plate 12, the solid electrolyte layer 14, and the negative electrode layer 16 and the end sealing portion 26 are sufficiently filled with the end insulating portion 18.
  • the sealing material may be a glass-based sealing material containing glass. It is preferable that the glass-based sealing material contains at least one selected from the group consisting of V, Sn, Te, P, Bi, B, Zn, and Pb from the viewpoint of easily obtaining a desired softening temperature and thermal expansion coefficient. Of course, these elements may be present in the glass in the form of V 2 O 5 , SnO, TeO 2 , P 2 O 5 , Bi 2 O 3 , B 2 O 3 , ZnO, and PbO. However, it is more preferable that the glass-based sealing material does not contain Pb or PbO which can be a harmful substance.
  • the glass-based sealing material preferably has a softening temperature of 400 ° C.
  • the softening temperature is not particularly limited with respect to the lower limit value, but may be, for example, 300 ° C or higher, 310 ° C or higher, or 320 ° C or higher.
  • the end sealing portion 26 can be formed at a relatively low temperature, and as a result, sealing with heating is performed. It is possible to effectively prevent the destruction and alteration of the battery due to the wearing.
  • the glass-based sealing material preferably has a thermal expansion coefficient of 7 ⁇ 10 ⁇ 6 / ° C.
  • the all-solid lithium battery preferably has a thickness of 60 to 5000 ⁇ m, more preferably 70 to 4000 ⁇ m, still more preferably 80 to 3000 ⁇ m, and particularly preferably. Is from 90 to 2000 ⁇ m, most preferably from 100 to 1000 ⁇ m.
  • the oriented positive electrode plate can be made relatively thick, while the current collector also serves as an exterior material, so that the thickness of the entire battery can be made relatively thin.
  • the oriented positive electrode plate or oriented sintered plate used in the all solid lithium battery of the present invention may be produced by any method, but preferably, as exemplified below (1) Production of LiCoO 2 template particles, (2) Production of matrix particles, (3) Production of green sheets, and (4) Production of oriented sintered plates.
  • LiCoO 2 Template Particles Co 3 O 4 raw material powder and Li 2 CO 3 raw material powder are mixed and fired (500 to 900 ° C., 1 to 20 hours) to synthesize LiCoO 2 powder.
  • the obtained LiCoO 2 powder is pulverized to a volume-based D50 particle size of 0.2 ⁇ m to 10 ⁇ m by a pot mill to obtain plate-like LiCoO 2 particles capable of conducting lithium ions in parallel with the plate surface.
  • Such LiCoO 2 particles can be obtained by a method of crushing after growing a green sheet using LiCoO 2 powder slurry, a plate method such as a flux method, hydrothermal synthesis, single crystal growth using a melt, or a sol-gel method.
  • the obtained LiCoO 2 particles are easily cleaved along the cleavage plane. It is to cleave by crushing the LiCoO 2 particles to prepare a LiCoO 2 template particles.
  • Co 3 O 4 raw material powder is used as matrix particles.
  • the volume-based D50 particle size of the Co 3 O 4 raw material powder is not particularly limited and can be, for example, 0.1 to 1.0 ⁇ m, but is preferably smaller than the volume-based D50 particle size of LiCoO 2 template particles.
  • the matrix particles can also be obtained by subjecting a Co (OH) 2 raw material to heat treatment at 500 ° C. to 800 ° C. for 1 to 10 hours.
  • Co (OH) 2 particles or LiCoO 2 particles may be used as matrix particles.
  • the slurry compact is placed on a zirconia setter and subjected to heat treatment (500 ° C. to 900 ° C., 1 to 10 hours) to obtain a sintered plate as an intermediate.
  • the sintered plate is sandwiched between lithium sheets so that the Li / Co ratio is 1.0, and the synthesized lithium sheet is placed on a zirconia setter.
  • the setter is put into an alumina sheath and fired in the atmosphere (700 to 850 ° C., 1 to 20 hours), and then the sintered plate is sandwiched between lithium sheets and further fired (750 to 900 ° C., 1 to 40 Time) to obtain a LiCoO 2 sintered plate.
  • This firing step may be performed in two steps or may be performed once. When firing twice, it is preferable that the first firing temperature is lower than the second firing temperature.
  • Examples A1 to A8 (1) Preparation of LCO template particles Co 3 O 4 raw material powder (volume basis D50 particle size 0.8 ⁇ m, manufactured by Shodo Chemical Co., Ltd.) and Li 2 CO 3 raw material powder (volume basis D50 particle size 2.5 ⁇ m, Honjo) Chemical) was mixed and baked at 800 ° C. to 900 ° C. for 5 hours to synthesize LiCoO 2 raw material powder. At this time, the volume-based D50 particle size of the LiCoO 2 raw material powder was adjusted as shown in Table 1 by adjusting the heat treatment temperature and the Li / Co ratio.
  • the obtained LiCoO 2 powder was pulverized to obtain plate-like LiCoO 2 particles (LCO template particles).
  • LCO template particles plate-like LiCoO 2 particles
  • a pot mill was used, and in Example A3, a wet jet mill was used.
  • the volume-based D50 particle size of the LCO template particles was adjusted as shown in Table 1 by adjusting the grinding time.
  • the aspect ratio of LiCoO 2 template particles were as shown in Table 1.
  • the aspect ratio of LiCoO 2 template particles was measured by observing the particles with SEM.
  • Co 3 O 4 raw material powder (manufactured by Shodo Chemical Industry Co., Ltd.) was used as matrix particles.
  • the volume-based D50 particle size of the matrix particles was as shown in Table 1. However, Example A4 did not use matrix particles.
  • a binder polyvinyl butyral: product number BM-2, manufactured by Sekisui Chemical Co., Ltd.
  • a plasticizer DOP : 4 parts by weight of Di (2-ethylhexyl) phthalate (manufactured by Kurokin Kasei Co., Ltd.) and 2 parts by weight of a dispersant (product name: Leodol SP-O30, manufactured by Kao Corporation) were mixed.
  • the mixture was degassed by stirring under reduced pressure, and a slurry was prepared by adjusting the viscosity to 40960000 cP.
  • the viscosity was measured with an LVT viscometer manufactured by Brookfield.
  • the prepared slurry was formed into a sheet on a PET film by a doctor blade method so that the thickness after drying was 40 ⁇ m at a forming speed of 100 m / h to obtain a green sheet.
  • the synthesized lithium sheet is subjected to secondary firing by placing it on a zirconia setter with the Co 3 O 4 sintered plate sandwiched between the lithium sheets so that the Li / Co ratio is as shown in Table 1.
  • a LiCoO 2 sintered plate Specifically, the zirconia setter was placed in a 90 mm square alumina sheath, held in the atmosphere at 800 ° C. for 5 hours, and then further sandwiched between lithium sheets and fired at 900 ° C. for 20 hours.
  • tungsten boat with lithium metal was prepared.
  • a vacuum deposition apparatus carbon coater SVC-700, manufactured by Sanyu Denshi
  • vapor deposition was performed in which Li was evaporated by resistance heating to form a thin film on the surface of the intermediate layer.
  • the size of the negative electrode layer was set to 9.5 mm square so that the negative electrode layer was within the 10 mm square positive electrode region. In this way, a unit cell was produced in which a Li-deposited film having a thickness of 10 ⁇ m was formed as a negative electrode layer on the solid electrolyte layer.
  • a 20 ⁇ m thick stainless steel foil was cut into a 13 mm square to form a positive electrode current collector. Also, a 1 mm wide frame-shaped modified polypropylene resin film (thickness: 100 ⁇ m) having an outer edge shape of 13 mm square and an 11 mm square hole punched inside thereof was prepared. This frame-shaped resin film was laminated on the outer peripheral portion on the positive electrode current collector plate, and heat-pressed to form an end sealing portion. The unit cell was placed in a region surrounded by the end sealing portion on the positive electrode current collector plate. Similarly to the above, a stainless steel foil having a thickness of 20 ⁇ m was placed on the negative electrode side of the placed unit cell, and heated at 200 ° C. under reduced pressure while applying a load to the end sealing portion. Thus, the end sealing part and the upper and lower two stainless steel foils were bonded together over the entire outer periphery to seal the unit cell. Thus, an all solid lithium battery in a sealed form was obtained.
  • the average orientation angle of the primary particles was calculated by arithmetically averaging the orientation angles of about 30 primary particles selected under the above conditions.
  • the calculation results were as shown in Table 2.
  • the angle formed between the plate surface and the (003) plane is within 30 degrees, more typically within 25 degrees, more typically within 20 degrees, particularly typically within 15 degrees, particularly typical.
  • it includes a plurality of crystal grains (primary particles) within 10 degrees, most typically within 5 degrees, and the (003) plane is oriented parallel to the plate surface of the oriented positive electrode plate. It was confirmed that a plurality of crystal grains were included.
  • the ratio (%) of the total area of primary particles having an orientation angle of more than 0 ° and 30 ° or less to the total area of about 30 primary particles used for calculating the average orientation angle was calculated.
  • the calculation results were as shown in Table 2.
  • the lithium ion battery was charged to 4.2 [V] at a constant current of 0.1 [mA], and then charged to 0.05 [mA] at a constant voltage. And it discharged to 3.0 [V] with a 0.2 [mA] constant current, and measured the discharge capacity W0. Moreover, after charging to 4.2 [V] at a constant current of 0.1 [mA], charging is performed until the current reaches 0.05 [mA] at a constant voltage, and then 3 at a constant current of 2.0 [mA]. The battery was discharged to 0.0 [V], and the discharge capacity W1 was measured. The rate performance was evaluated by dividing W1 by W0.
  • Example B1 (comparison) In this example, the (104) plane is aligned in parallel to the plate surface (that is, the (003) plane is not aligned in parallel to the plate surface), and an all-solid-state in which the aligned positive plate is bonded to the current collector plate. It is the comparative example which produced and evaluated the lithium battery.
  • a binder polyvinyl butyral: product number BM-2, manufactured by Sekisui Chemical Co., Ltd.
  • a plasticizer DOP : 4 parts by weight of di (2-ethylhexyl) phthalate (manufactured by Kurokin Kasei Co., Ltd.) and 2 parts by weight of a dispersant (product name: Leodol SP-O30, Kao Corporation) were mixed.
  • the mixture was defoamed by stirring under reduced pressure and adjusted to a viscosity of 4000 cP.
  • the viscosity was measured with an LVT viscometer manufactured by Brookfield.
  • the slurry prepared as described above was formed into a sheet shape on a PET (polyethylene terephthalate) film so that the thickness after drying was 40 ⁇ m by a doctor blade method to obtain a green sheet.
  • the bulk density of the obtained sintered plate was measured by Archimedes method, and the density was calculated by dividing the bulk density by the true density of lithium cobaltate of 5.05 g / cm 3 . As a result, the density of the sintered plate was 97%.
  • the lithium cobaltate oriented sintered plate is cut into a 10 mm square, and the conductive film surface of the oriented sintered plate is made of an epoxy resin-based conductive adhesive in which conductive carbon is dispersed.
  • a current collector plate positive electrode outer packaging material, 13 mm square, thickness 100 ⁇ m
  • a flat plate-like laminated positive electrode plate / conductive adhesive / positive electrode outer packaging layer plate was obtained.
  • end sealing portion was produced by laminating a modified polypropylene resin film (thickness: 100 ⁇ m) on the end portion of the unit cell (the outer peripheral portion of the positive electrode current collector plate). .
  • the all-solid-state lithium battery was charged to 4.1 V at a constant current of 0.1 mA, and then charged to a current of 0.02 mA at a constant voltage to obtain a charge capacity. Then, it discharged to 3.0V with a 0.1 mA constant current. This operation was repeated 50 times.
  • the internal resistance R of the battery was calculated from the IR drop 10 seconds after the start of discharge, and the internal resistance at the fifth discharge was R 5 and the internal resistance R 50 at the 50th discharge. To R 50 have the value obtained by dividing the rate of change in resistance R 5. When five batteries were produced and evaluated and the average was taken, the resistance change rate was 220%.
  • Example B2 (comparison) In this example, the (104) plane is aligned in parallel with the plate surface (that is, the (003) plane is not aligned in parallel with the plate surface) and the aligned positive plate is not bonded to the current collector plate. It is the comparative example which produced and evaluated the solid lithium battery.
  • a binder polyvinyl butyral: product number BM-2, manufactured by Sekisui Chemical Co., Ltd.
  • a plasticizer DOP : 4 parts by weight of di (2-ethylhexyl) phthalate (manufactured by Kurokin Kasei Co., Ltd.) and 2 parts by weight of a dispersant (product name: Leodol SP-O30, Kao Corporation) were mixed.
  • the mixture was defoamed by stirring under reduced pressure and adjusted to a viscosity of 4000 cP.
  • the viscosity was measured with an LVT viscometer manufactured by Brookfield.
  • the slurry prepared as described above was formed into a sheet shape on a PET (polyethylene terephthalate) film so that the thickness after drying was 40 ⁇ m by a doctor blade method to obtain a green sheet.
  • the battery thus obtained is in a state where the aligned positive electrode plate is not bonded to the current collector plate. That is, in the obtained battery, the positive electrode current collector is entirely in contact with the surface of the oriented positive electrode plate opposite to the solid electrolyte layer in a non-adhesive state that does not contain an adhesive.
  • Example B3 This example is an example in which an all-solid-state lithium battery was prepared and evaluated in a state in which an oriented positive plate with the (003) plane oriented parallel to the plate surface was not bonded to the current collector plate.
  • Example A2 (1) Production of Oriented Positive Electrode Plate
  • an oriented positive plate having a (003) plane oriented parallel to the plate surface was produced according to the conditions shown in Table 1.
  • the characteristics of the obtained oriented positive electrode plate are as shown in Table 2.

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Abstract

Provided is an all-solid-state lithium cell with good cell characteristics with which it is possible to significantly reduce the rate of increase in resistance during repeated use, even when a thick positive electrode plate comprising a sintered compact is used, whereby long-term reliability is greatly improved. This all-solid-state lithium cell is provided with: an independent oriented positive electrode plate having a thickness of 20 μm or more and comprising an oriented sintered body; a solid-state electrolyte layer constituted from a lithium ion conducting material; a negative electrode layer containing lithium; and a positive electrode collector, which is a metal foil having a thickness of 5-30 μm and which is in full-surface contact with the surface of the oriented positive electrode plate on the opposite side from the solid-state electrolyte layer in a non-adhesive state devoid of adhesive. This oriented positive electrode plate includes a plurality of crystal grains composed of a lithium composite oxide in which the oriented sintered body has a layered rock-salt structure, the plurality of crystal grains having the (003) plane oriented parallel to the plate surface of the oriented positive electrode plate.

Description

全固体リチウム電池All solid lithium battery
　本発明は、全固体リチウム電池に関するものである。 The present invention relates to an all solid lithium battery.
　正極としてセラミックス焼結体を用いて電池を作製する試みが提案されている。例えば、特許文献１（特許第３４２７５７０号公報）には、炭素質材料、リチウム金属又はリチウム合金からなる負極と、リチウム複合酸化物の焼結体からなる正極と、非水電解質とを有する、非水電解質二次電池が開示されている。また、特許文献２（特許第５７７５４４４号公報）には、シート状の導電性芯材と、カーボン層と、活物質層と、被覆層と有する非水電解質電池用電極が開示されており、活物質層が、リチウムを吸蔵及び／又は放出可能な遷移金属酸化物の焼結体で構成される厚さ２０～１２０μｍのセラミックス膜を含むことが開示されている。 An attempt to produce a battery using a ceramic sintered body as a positive electrode has been proposed. For example, Patent Document 1 (Japanese Patent No. 3427570) includes a negative electrode made of a carbonaceous material, lithium metal or a lithium alloy, a positive electrode made of a sintered body of a lithium composite oxide, and a nonaqueous electrolyte. A water electrolyte secondary battery is disclosed. Patent Document 2 (Japanese Patent No. 5775444) discloses a nonaqueous electrolyte battery electrode having a sheet-like conductive core material, a carbon layer, an active material layer, and a coating layer. It is disclosed that the material layer includes a ceramic film having a thickness of 20 to 120 μm formed of a sintered body of a transition metal oxide capable of occluding and / or releasing lithium.
　ところで、パーソナルコンピュータ、携帯電話等のポータブル機器といったような用途に用いられる電池においては、イオンを移動させる媒体として、リチウム塩を可燃性の有機溶媒へ溶解させた、液体の電解質（電解液）が従来使用されている。このような電解液を用いた電池においては、電解液の漏液や、発火、爆発等の問題を生ずる可能性がある。このような問題を解消すべく、本質的な安全性確保のために、液体の電解質に代えて固体電解質を使用するとともに、その他の要素の全てを固体で構成した全固体リチウム電池の開発が進められている。このような全固体リチウム電池は、電解質が固体であることから、発火の心配が少なく、漏液せず、また、腐食による電池性能の劣化等の問題も生じ難い。例えば、特許文献３（特開２０１３－１０５７０８号公報）には、コバルト酸リチウム（ＬｉＣｏＯ２）からなる正極層と、金属リチウムからなる負極層と、リン酸リチウムオキシナイトライドガラス電解質（ＬｉＰＯＮ）で形成されうる固体電解質層とを備えた薄膜リチウム二次電池が開示されており、正極層がスパッタリングにより形成され、その厚さは１～１５μｍの範囲であることが記載されている。この文献において、薄膜リチウム二次電池の製造は、基板上に、コバルト酸リチウムからなる正極層を形成し、当該正極層上に固体電解質層を形成し、当該固体電解質層上に金属リチウムからなる負極層を形成することにより行われている。 By the way, in batteries used for applications such as portable devices such as personal computers and mobile phones, a liquid electrolyte (electrolytic solution) in which lithium salt is dissolved in a flammable organic solvent is used as a medium for moving ions. Conventionally used. A battery using such an electrolytic solution may cause problems such as leakage of the electrolytic solution, ignition, and explosion. In order to solve these problems, in order to ensure essential safety, the development of an all-solid-state lithium battery in which a solid electrolyte is used instead of a liquid electrolyte and all other elements are made of solid is progressed. It has been. Such an all-solid-state lithium battery has a solid electrolyte, so there is little fear of ignition, no leakage, and problems such as deterioration of battery performance due to corrosion hardly occur. For example, Patent Document 3 (Japanese Patent Laid-Open No. 2013-105708) describes a positive electrode layer made of lithium cobaltate (LiCoO 2 ), a negative electrode layer made of metallic lithium, and a lithium phosphate oxynitride glass electrolyte (LiPON). A thin-film lithium secondary battery including a solid electrolyte layer that can be formed is disclosed, and it is described that a positive electrode layer is formed by sputtering and has a thickness in the range of 1 to 15 μm. In this document, a thin film lithium secondary battery is manufactured by forming a positive electrode layer made of lithium cobaltate on a substrate, forming a solid electrolyte layer on the positive electrode layer, and forming metal lithium on the solid electrolyte layer. This is done by forming a negative electrode layer.
　一方、層状岩塩構造を有するリチウム複合酸化物からなる正極活物質においては、その内部でのリチウムイオン（Ｌｉ＋）の拡散が（００３）面の面内方向（すなわち（００３）面と平行な平面内の任意の方向）で行われる一方、（００３）面以外の結晶面（例えば（１０１）面や（１０４）面）でリチウムイオンの出入りが生じることが知られている。そこで、この種の正極活物質において、リチウムイオンの出入りが良好に行われる結晶面（（００３）面以外の面、例えば（１０１）面や（１０４）面））をより多く電解質と接触する表面に露出させることで、リチウム二次電池の電池特性を向上させる試みがなされている。例えば、特許文献４（国際公開第２０１０／０７４３０４号）には、Ｃｏ３Ｏ４を含むグリーンシートを焼成して（ｈ００）面がシート面と平行に配向したＣｏ３Ｏ４粒子を含むシートを形成し、その後Ｌｉを導入することにより、（１０４）面がシート面と平行に配向したＬｉＣｏＯ２セラミックスシート（正極活物質膜）を製造することが開示されている。特許文献１の手法によれば、板面に露出する各一次粒子の配向方位を、［１０１］方向や［１０４］方向にすることができる。一次粒子の配向方位が［１０１］方向であれば、一次粒子の（００３）面は板面に対して約７５度傾いた状態となる。一次粒子の配向方位が［１０４］方向であれば、一次粒子の（００３）面は板面に対して約４８度傾いた状態となる。 On the other hand, in a positive electrode active material composed of a lithium composite oxide having a layered rock salt structure, the diffusion of lithium ions (Li + ) therein is a plane parallel to the (003) plane (ie, the (003) plane). On the other hand, it is known that lithium ions enter and exit in crystal planes other than the (003) plane (for example, (101) plane or (104) plane). Therefore, in this type of positive electrode active material, a surface that comes into contact with the electrolyte more in a crystal plane (a plane other than the (003) plane, for example, the (101) plane or the (104) plane) on which lithium ions can enter and exit satisfactorily. Attempts have been made to improve the battery characteristics of lithium secondary batteries by exposing them to the above. For example, Patent Document 4 (WO 2010/074304), a sheet containing Co 3 O 4 particles by firing a green sheet (h00) face is oriented parallel to the sheet surface including Co 3 O 4 It is disclosed that a LiCoO 2 ceramic sheet (positive electrode active material film) having a (104) plane oriented parallel to the sheet surface is produced by forming and then introducing Li. According to the method of Patent Document 1, the orientation direction of each primary particle exposed on the plate surface can be set to the [101] direction or the [104] direction. If the orientation direction of the primary particles is the [101] direction, the (003) plane of the primary particles is inclined by about 75 degrees with respect to the plate surface. If the orientation direction of the primary particles is the [104] direction, the (003) plane of the primary particles is inclined by about 48 degrees with respect to the plate surface.
特許第３４２７５７０号公報Japanese Patent No. 3427570 特許第５７７５４４４号公報Japanese Patent No. 5775444 特開２０１３－１０５７０８号公報JP 2013-105708 A 国際公開第２０１０／０７４３０４号International Publication No. 2010/0704304
　ところで、層状岩塩構造のリチウム複合酸化物は、リチウムイオンが抜けるのに伴い、層間距離が広がる性質があることから、そのセラミックス焼結体からなる正極板は、充放電に伴うＬｉイオンの脱挿入に伴い寸法変化する。このため、固体電解質層に対して引張応力が発生し、固体電解質層の破損や剥がれ、クラック発生等による電気的なショートや抵抗増加を引き起こすことがあった。 また、正極板内で構成する結晶粒子の方位がバラバラである場合、充放電に伴い粒子間で応力が発生し、充放電性能の低下を招くことがあった。さらに、不均一な寸法変化に伴う応力の発生を低減すべく、正極板全体を均一に充放電させることが望まれる。また、全固体リチウム電池の場合、固体電解質内のＬｉイオンの板面平行方向の移動が期待できないことから、正極板の充放電が面内で不均一であると、負極側も正極と同様に不均一に充放電することになるため、充放電性能の低下を招く。この点、電解液を用いた液系電池の場合には、電解液中でＬｉイオンが全方位的に濃度拡散できるため、正極板表面に起こりうるＬｉイオンの濃度ムラが容易に緩和し、負極は均一に充放電できる。これは特に正極板表面の電解液中における、Ｌｉイオンの板面平行方向への移動によるものである。そこで、全固体電池において、正極板の板面方向で均一な充放電を可能とすべく、集電層として、面内方向の抵抗が十分に低い導電剤を正極板の裏面に均一に形成することが考えられる。緻密度が高く、厚く、しかも高エネルギー密度な設計の正極板においては、例えば、正極板の表面に厚さ１０μｍ以上の金属膜を焼付け等により形成する、或いは正極板の表面に厚さ５μｍ以上の金属箔（集電箔）を導電性接着剤を介して接合させる等の特段の構成が必要となる。いずれの構成も、正極板が充放電で膨張収縮することに起因し、深い充放電深度で使用したり、或いは長期間使用したりする中で、界面剥離等の劣化要因により接触抵抗の増大を招き、それ故、信頼性に問題があった。このように、全固体リチウム電池の正極として、緻密で厚いセラミックス焼結体からなる正極板を用いる場合、長期的な信頼性における更なる改善が望まれる。 By the way, the lithium composite oxide with a layered rock salt structure has the property that the interlayer distance increases as lithium ions are released. Dimension changes with. For this reason, tensile stress is generated with respect to the solid electrolyte layer, which may cause an electrical short circuit or an increase in resistance due to breakage or peeling of the solid electrolyte layer or generation of cracks. In addition, when the orientations of the crystal grains constituting the positive electrode plate are different, stress is generated between the grains along with charge / discharge, which may cause deterioration of charge / discharge performance. Furthermore, it is desirable to uniformly charge and discharge the entire positive electrode plate in order to reduce the generation of stress associated with non-uniform dimensional changes. In addition, in the case of an all-solid lithium battery, since movement of Li ions in the solid electrolyte in the plate surface parallel direction cannot be expected, if the charge and discharge of the positive electrode plate is uneven in the plane, the negative electrode side is also the same as the positive electrode Since charging / discharging is performed unevenly, the charging / discharging performance is reduced. In this regard, in the case of a liquid battery using an electrolytic solution, since Li ions can be diffused in all directions in the electrolytic solution, concentration unevenness of Li ions that can occur on the surface of the positive electrode plate can be easily mitigated, and the negative electrode Can charge and discharge uniformly. This is particularly due to the movement of Li ions in the direction parallel to the plate surface in the electrolyte solution on the surface of the positive electrode plate. Therefore, in an all-solid-state battery, a conductive agent having a sufficiently low resistance in the in-plane direction is uniformly formed on the back surface of the positive electrode plate as a current collecting layer to enable uniform charge and discharge in the plate surface direction of the positive electrode plate. It is possible. In a positive electrode plate having a high density, a high thickness, and a high energy density, for example, a metal film having a thickness of 10 μm or more is formed on the surface of the positive electrode plate by baking or the like, or a thickness of 5 μm or more is formed on the surface of the positive electrode plate. A special configuration is required, such as bonding the metal foil (current collector foil) through a conductive adhesive. In any configuration, the positive electrode plate expands and contracts due to charge / discharge, and the contact resistance increases due to deterioration factors such as interfacial peeling during use at a deep charge / discharge depth or for a long period of time. Invited, therefore, there was a problem with reliability. Thus, when a positive electrode plate made of a dense and thick ceramic sintered body is used as the positive electrode of the all-solid-state lithium battery, further improvement in long-term reliability is desired.
　本発明者らは、今般、層状岩塩構造を有するリチウム複合酸化物の焼結体からなる厚い正極板を採用した全固体リチウム電池において、（００３）面が板面に対して平行に配向した配向正極板を採用し、なおかつ、その配向正極板を接着剤を伴わない非接着状態で薄い正極集電体に全面的に接触させることにより、繰り返し使用時の抵抗増加率を有意に低減でき、その結果、長期的な信頼性を大幅に改善できるとの知見を得た。また、かかる構成によりレート特性及びサイクル特性といった電池特性も良好であるとの知見も得た。 In an all-solid lithium battery employing a thick positive electrode plate made of a lithium composite oxide sintered body having a layered rock salt structure, the present inventors have orientated the (003) plane parallel to the plate surface. By adopting a positive electrode plate and bringing the oriented positive electrode plate into full contact with the thin positive electrode current collector in a non-adhered state without an adhesive, the resistance increase rate during repeated use can be significantly reduced. As a result, we have learned that long-term reliability can be greatly improved. Moreover, the knowledge that battery characteristics, such as a rate characteristic and a cycle characteristic, were also favorable was acquired by this structure.
　したがって、本発明の目的は、焼結体からなる厚い正極板を採用しながらも、繰り返し使用時の抵抗増加率を有意に低減でき、それ故、長期的な信頼性が大幅に改善された良好な電池特性の全固体リチウム電池を提供することにある。 Therefore, the object of the present invention is to improve the resistance increase rate during repeated use while adopting a thick positive electrode plate made of a sintered body, and therefore the long-term reliability is greatly improved. The object is to provide an all-solid-state lithium battery having excellent battery characteristics.
　本発明の一態様によれば、配向焼結体からなる厚さ２０μｍ以上の自立した配向正極板であって、前記配向焼結体が層状岩塩構造を有するリチウム複合酸化物で構成される複数の結晶粒を含み、前記複数の結晶粒は（００３）面が前記配向正極板の板面に対して平行に配向している、配向正極板と、
　前記配向正極板上に設けられ、リチウムイオン伝導材料で構成される固体電解質層と、
　前記固体電解質層上に設けられる、リチウムを含む負極層と、
　前記配向正極板の前記固体電解質層と反対側の面に、接着剤を含まない非接着状態で全面的に接触されている、厚さ５μｍ以上３０μｍ以下の金属箔である正極集電体と、
を備えた、全固体リチウム電池が提供される。 According to one aspect of the present invention, a self-supporting oriented positive electrode plate having a thickness of 20 μm or more made of an oriented sintered body, wherein the oriented sintered body comprises a plurality of lithium composite oxides having a layered rock salt structure. An oriented positive electrode plate comprising crystal grains, wherein the plurality of crystal grains have a (003) plane oriented parallel to a plate surface of the oriented positive electrode plate;
A solid electrolyte layer provided on the oriented positive electrode plate and made of a lithium ion conductive material;
A negative electrode layer containing lithium provided on the solid electrolyte layer;
A positive electrode current collector which is a metal foil having a thickness of 5 μm or more and 30 μm or less, which is in full contact with the surface opposite to the solid electrolyte layer of the oriented positive electrode plate in a non-adhesive state not containing an adhesive;
An all-solid lithium battery is provided.
本発明の全固体リチウム電池の一例を示す模式断面図である。It is a schematic cross section which shows an example of the all-solid-state lithium battery of this invention. 図１に示される全固体リチウム電池の模式上面図である。It is a model top view of the all-solid-state lithium battery shown by FIG. 本発明の全固体リチウム電池の他の一例を示す模式断面図である。It is a schematic cross section which shows another example of the all-solid-state lithium battery of this invention. 本発明の全固体リチウム電池の更に他の一例を示す模式断面図である。It is a schematic cross section which shows another example of the all-solid-state lithium battery of this invention. 本発明の配向正極板に含まれるリチウム複合酸化物結晶粒のリチウムイオン伝導方向と膨張収縮方法とを概念的に説明するための模式断面図である。It is a schematic cross section for conceptually explaining the lithium ion conduction direction and the expansion / contraction method of the lithium composite oxide crystal grains contained in the oriented positive electrode plate of the present invention. 従来の配向正極板の一例におけるリチウムイオン伝導方向と膨張収縮方法とを概念的に説明するための模式断面図である。It is a schematic cross section for conceptually explaining a lithium ion conduction direction and an expansion / contraction method in an example of a conventional oriented positive electrode plate. 本発明に用いられる配向正極板の板面に垂直な破断面の一例を示す破断面ＳＥＭ画像である。It is a fracture surface SEM image which shows an example of the fracture surface perpendicular | vertical to the plate | board surface of the orientation positive electrode plate used for this invention. 図７に示されるような本発明に用いられる配向正極板におけるリチウムイオン伝導方向と膨張収縮方法とを概念的に説明するための模式断面図である。FIG. 8 is a schematic cross-sectional view for conceptually explaining the lithium ion conduction direction and the expansion / contraction method in the oriented positive electrode plate used in the present invention as shown in FIG. 7. 本発明の配向正極板の板面に垂直な断面の一例を示すＳＥＭ像である。It is a SEM image which shows an example of a cross section perpendicular | vertical to the plate | board surface of the orientation positive electrode plate of this invention. 図９Ａにおいて四角形の枠で特定される測定領域における、配向正極板の断面のＥＢＳＤ像である。FIG. 9B is an EBSD image of a cross section of the aligned positive electrode plate in a measurement region specified by a rectangular frame in FIG. 9A.
　全固体リチウム電池
　図１及び２に本発明による全固体リチウム電池の一例を模式的に示す。図１及び２に示される全固体リチウム電池１０は、配向正極板１２、固体電解質層１４、負極層１６、及び正極集電体２０を備える。図１に示される全固体リチウム電池１０は、配向正極板１２、固体電解質層１４、負極層１６、及び正極集電体２０で構成される２個の単位電池を負極集電体２４を介して上下対称に並列積層した構成を有している。もっとも、これに限らず、図３に模式的に示されるように１つの単位電池１０’からなる構成であってもよいし、２つ以上の単位電池を並列又は直列に積層した構成であってもよい。配向正極板１２は、配向焼結体からなる厚さ２０μｍ以上の自立した板であって、配向焼結体は層状岩塩構造を有するリチウム複合酸化物で構成される複数の結晶粒を含む。これらの複数の結晶粒は（００３）面が配向正極板１２の板面に対して平行に配向している。固体電解質層１４は、配向正極板１２上に設けられ、リチウムイオン伝導材料で構成される。負極層１６は、固体電解質層１４上に設けられ、リチウムを含む層である。正極集電体２０は、厚さ５μｍ以上３０μｍ以下の金属箔であり、配向正極板１２の固体電解質層１４と反対側の面に、接着剤を含まない非接着状態で全面的に接触されている。このように、焼結体からなる厚い配向正極板を採用した全固体リチウム電池において、配向正極板を、接着剤を伴わない非接着状態で薄い正極集電体に全面的に接触させることにより、繰り返し使用時の抵抗増加率を有意に低減でき、その結果、長期的な信頼性を大幅に改善することができる。すなわち、厚さ５μｍ以上３０μｍ以下の金属箔である正極集電体２０は柔軟性のある薄い導電性材料であるため、配向正極板１２の表面に全面的に均一に密着することができる。もっとも、金属箔である正極集電体２０と配向正極板１２とは、微視的には互いに点接触となるため、面内で集電ムラが生じうる。しかしながら、接触点の間隔は配向正極板１２の厚さ（２０μｍ以上）に対して有意に小さいことから、接触点から位置ずれによる集電ムラを配向正極板１２の厚さ方向へのＬｉイオン拡散で相殺できるため、板面内での充放電ムラを無くすことができる。しかも、配向正極板１２が正極集電体２０に接着剤フリーの非接着状態で集電が行われるため、配向正極板１２の膨張収縮によっても、正極集電体２０は基本的に追随されない。また、仮にそうではなかったとしても正極集電体２０は薄い金属箔であるためそれ自体の延性により膨張収縮にある程度は追随することができる。いずれにしても、配向正極板１２は膨張収縮に応じて、正極集電体２０との接触を確保しながら、正極集電体２０に対して相対的に動くことができる。このため、配向正極板１２と正極集電体２０の間での界面応力が発生せず、それ故界面剥離等の劣化要因を排除することができる。こうして長期的な信頼性が大幅に改善されるものと考えられる。すなわち、配向正極板１２が充放電で膨張収縮することに起因する界面剥離及びそれによる接触抵抗の増大を有意に抑制することができ、長期的な信頼性を改善することができる。しかも、後述するように、（００３）面が配向正極板の板面に対して平行に配向した配向正極板の採用により、レート特性及びサイクル特性といった電池特性も良好となる。 All Solid Lithium Battery FIGS. 1 and 2 schematically show an example of an all solid lithium battery according to the present invention. An all solid lithium battery 10 shown in FIGS. 1 and 2 includes an oriented positive electrode plate 12, a solid electrolyte layer 14, a negative electrode layer 16, and a positive electrode current collector 20. An all-solid lithium battery 10 shown in FIG. 1 includes two unit batteries each composed of an oriented positive electrode plate 12, a solid electrolyte layer 14, a negative electrode layer 16, and a positive electrode current collector 20 via a negative electrode current collector 24. It has a configuration in which the layers are vertically stacked in parallel. However, the present invention is not limited to this, and may be configured by one unit cell 10 ′ as schematically shown in FIG. 3, or may be configured by stacking two or more unit cells in parallel or in series. Also good. The oriented positive electrode plate 12 is a self-supporting plate having a thickness of 20 μm or more made of an oriented sintered body, and the oriented sintered body includes a plurality of crystal grains composed of a lithium composite oxide having a layered rock salt structure. These crystal grains have a (003) plane oriented parallel to the plate surface of the oriented positive electrode plate 12. The solid electrolyte layer 14 is provided on the oriented positive electrode plate 12 and is made of a lithium ion conductive material. The negative electrode layer 16 is a layer provided on the solid electrolyte layer 14 and containing lithium. The positive electrode current collector 20 is a metal foil having a thickness of 5 μm or more and 30 μm or less, and is in full contact with the surface opposite to the solid electrolyte layer 14 of the oriented positive electrode plate 12 in a non-adhesive state not containing an adhesive. Yes. Thus, in an all solid lithium battery employing a thick alignment positive electrode plate made of a sintered body, the alignment positive electrode plate is brought into full contact with a thin positive electrode current collector in a non-adhesive state without an adhesive. The rate of increase in resistance during repeated use can be significantly reduced, and as a result, long-term reliability can be greatly improved. That is, the positive electrode current collector 20, which is a metal foil having a thickness of 5 μm or more and 30 μm or less, is a flexible thin conductive material, and therefore can be uniformly adhered to the entire surface of the oriented positive electrode plate 12. However, since the positive electrode current collector 20 and the alignment positive electrode plate 12 which are metal foils are in point contact with each other microscopically, current collection unevenness may occur in the plane. However, since the distance between the contact points is significantly smaller than the thickness of the alignment positive electrode plate 12 (20 μm or more), unevenness of current collection due to misalignment from the contact point causes Li ion diffusion in the thickness direction of the alignment positive electrode plate 12. Therefore, uneven charging / discharging within the plate surface can be eliminated. Moreover, since the aligned positive electrode plate 12 collects current with the positive electrode current collector 20 in an adhesive-free non-adhered state, the positive electrode current collector 20 does not basically follow even when the aligned positive electrode plate 12 expands and contracts. Even if this is not the case, since the positive electrode current collector 20 is a thin metal foil, it can follow expansion and contraction to some extent due to its ductility. In any case, the oriented positive electrode plate 12 can move relative to the positive electrode current collector 20 while ensuring contact with the positive electrode current collector 20 according to expansion and contraction. For this reason, the interface stress between the oriented positive electrode plate 12 and the positive electrode current collector 20 does not occur, and therefore, deterioration factors such as interface peeling can be eliminated. Thus, long-term reliability is considered to be greatly improved. That is, interfacial peeling caused by expansion and contraction of the alignment positive electrode plate 12 due to charge and discharge and an increase in contact resistance caused thereby can be significantly suppressed, and long-term reliability can be improved. In addition, as will be described later, battery characteristics such as rate characteristics and cycle characteristics are also improved by adopting an oriented positive plate whose (003) plane is oriented parallel to the plate surface of the oriented positive plate.
　正極集電体
　正極集電体２０は金属箔である。金属箔の厚さは５～３０μｍであり、好ましくは５～２５μｍ、より好ましくは１０～２５μｍ、さらに好ましくは１０～２０μｍである。このように厚くすることで十分な集電機能を確保することができる。正極集電体２０は、配向正極板１２の固体電解質層１４と反対側の面に、接着剤を含まない非接着状態で全面的に接触されている。このため、上記のように極めて薄い金属箔であると柔軟性に富むため、配向正極板１２の表面に全面的に均一に密着させやすくなる。正極集電体２０を構成する金属は、配向正極板１２と反応しないものであれば特に限定されず、合金であってもよい。そのような金属の好ましい例としては、ステンレス、アルミニウム、銅、白金、ニッケルが挙げられ、より好ましくはステンレス及びニッケルが挙げられる。 Positive Current Collector The positive current collector 20 is a metal foil. The thickness of the metal foil is 5 to 30 μm, preferably 5 to 25 μm, more preferably 10 to 25 μm, and still more preferably 10 to 20 μm. By increasing the thickness as described above, a sufficient current collecting function can be ensured. The positive electrode current collector 20 is entirely in contact with the surface of the oriented positive electrode plate 12 opposite to the solid electrolyte layer 14 in a non-adhesive state that does not contain an adhesive. For this reason, since it is rich in flexibility when it is a very thin metal foil as described above, it becomes easy to adhere to the entire surface of the alignment positive electrode plate 12 uniformly. The metal constituting the positive electrode current collector 20 is not particularly limited as long as it does not react with the aligned positive electrode plate 12, and may be an alloy. Preferred examples of such metals include stainless steel, aluminum, copper, platinum, and nickel, and more preferably stainless steel and nickel.
　正極集電体２０は、配向正極板１２の外側を被覆する正極外装材を兼ねているのが好ましい。例えば、図１に示されるように２個の単位電池を１枚の負極集電体２４を介して上下対称に並列積層して正極集電体２０を全固体リチウム電池１０の外側に露出させた構成としてもよい。このような並列積層型電池に構成される場合、負極集電体２４を隣り合う２個の単位電池に共通の集電体として機能させることができる。 It is preferable that the positive electrode current collector 20 also serves as a positive electrode exterior material that covers the outer side of the aligned positive electrode plate 12. For example, as shown in FIG. 1, two unit cells are stacked in parallel symmetrically via a single negative electrode current collector 24 to expose the positive electrode current collector 20 to the outside of the all-solid-state lithium battery 10. It is good also as a structure. When configured in such a parallel stacked battery, the negative electrode current collector 24 can function as a current collector common to two adjacent unit batteries.
　正極集電体２０は、配向正極板１２に対して押圧されているのが好ましい。正極集電体２０である金属箔は柔軟性のある薄い導電性材料であるため、押圧により正極集電体２０と配向正極板１２との接触点を多く確保することができ、配向正極板１２の表面に全面的により均一に密着させることができる。それによって、接着剤フリーの非接着状態でありながらも望ましい集電効果を得ることができる。押圧する手法は特に限定されず、例えば、正極集電体２０を損傷しないような柔軟な押圧部材（例えば発泡金属）を用いて正極集電体２０の外側から配向正極板１２に向かって押し当てる手法、正極集電体２０の内外気圧差を用いる手法等が採用可能である。特に、正極集電体２０の配向正極板１２に対する押圧が、正極集電体２０の内外気圧差によってもたらされているのが好ましい。すなわち、正極集電体２０の配向正極板１２側が減圧されているか、又は正極集電体２０の配向正極板１２と反対側が加圧されていればよい。いずれにしても、正極集電体２０の内外気圧差を用いた押圧によれば、正極集電体２０である金属箔は柔軟性のある薄い導電性材料であるため、配向正極板１２の表面により一層多くの接触点で密着させることができ、集電効果を更に高めることができる。正極集電体２０と配向正極板１２が非接着状態ということは、正極集電体２０と配向正極板１２が部分的に（例えば配向正極板１２の外周部の一部）、粘着性の樹脂等で固定されていることを排除するものではない。このような樹脂は、電池を組み立てる際、配向正極板の位置ズレを防止する仮接着の目的で使用される。 The positive electrode current collector 20 is preferably pressed against the aligned positive electrode plate 12. Since the metal foil which is the positive electrode current collector 20 is a flexible thin conductive material, a large number of contact points between the positive electrode current collector 20 and the alignment positive electrode plate 12 can be secured by pressing, and the alignment positive electrode plate 12 can be secured. Can be more uniformly adhered to the entire surface. Thereby, a desirable current collecting effect can be obtained while being in an adhesive-free non-adhered state. The method of pressing is not particularly limited. For example, the pressing is performed from the outside of the positive electrode current collector 20 toward the alignment positive electrode plate 12 using a flexible pressing member (for example, foam metal) that does not damage the positive electrode current collector 20. A method, a method using a pressure difference between the inside and outside of the positive electrode current collector 20, or the like can be employed. In particular, it is preferable that the positive current collector 20 is pressed against the oriented positive electrode plate 12 due to a difference in internal and external pressures of the positive current collector 20. That is, it is only necessary that the orientation positive electrode plate 12 side of the positive electrode current collector 20 is depressurized or the side opposite to the orientation positive electrode plate 12 of the positive electrode current collector 20 is pressurized. In any case, since the metal foil as the positive electrode current collector 20 is a flexible thin conductive material according to the pressing using the internal and external pressure difference of the positive electrode current collector 20, the surface of the oriented positive electrode plate 12 Thus, the contact can be made at more contact points, and the current collecting effect can be further enhanced. The positive electrode current collector 20 and the aligned positive electrode plate 12 are in a non-adhered state. This means that the positive electrode current collector 20 and the aligned positive electrode plate 12 are partially (for example, part of the outer peripheral portion of the aligned positive electrode plate 12) and are adhesive resins. It is not excluded that it is fixed by, for example. Such a resin is used for the purpose of temporary adhesion to prevent misalignment of the oriented positive electrode plate when assembling the battery.
　本発明の特に好ましい態様によれば、配向正極板１２、固体電解質層１４及び負極層１６を含む積層体が外装材で包装又は封止される。この態様において、正極集電体２０が外装材の一部を構成し、かかる外装材で包装又は封止される積層体の収容空間が減圧されているのが好ましい。収容空間の減圧は、例えば、減圧下にて外装材での包装又は封止を行う、又は外装材の包装又は封止を行った後に収容空間を脱気することにより行うことができる。上述のとおり、正極集電体２０である金属箔は柔軟性のある薄い導電性材料であるため、収容空間の減圧により、正極集電体２０を配向正極板１２の表面により一層多くの接触点で密着させることができる。しかも、外装材で気密に包装又は封止していれば、積層体の収容空間の減圧を長期間にわたって維持することができるので、高度な密着性及びそれによるい良好な集電効果を長期間にわたって発揮させることができる。減圧度は、金属の柔軟性と、積層体の強度等から適宜設定すればよい。 According to a particularly preferred aspect of the present invention, the laminate including the oriented positive electrode plate 12, the solid electrolyte layer 14, and the negative electrode layer 16 is packaged or sealed with an exterior material. In this aspect, it is preferable that the positive electrode current collector 20 constitutes a part of the exterior material, and the accommodation space of the laminate that is packaged or sealed with the exterior material is decompressed. The storage space can be depressurized, for example, by packaging or sealing with an exterior material under reduced pressure, or by degassing the storage space after packaging or sealing the exterior material. As described above, since the metal foil that is the positive electrode current collector 20 is a flexible thin conductive material, the contact point of the positive electrode current collector 20 with the surface of the aligned positive electrode plate 12 is increased by reducing the storage space. Can be brought into close contact with. Moreover, if the packaging material is packaged or sealed in an airtight manner, it is possible to maintain a reduced pressure in the accommodation space of the laminate over a long period of time. Can be exerted over. The degree of vacuum may be set as appropriate based on the flexibility of the metal and the strength of the laminate.
　所望により、正極集電体２０は、固体電解質層１４側の面にカーボン膜を備えていてもよい。こうすることで、正極集電体２０と配向正極板１２との電子伝導性を高め、界面における接触抵抗をより一層低減することができる。カーボン膜の厚さは、好ましくは０．０１μｍ以上５μｍ以下、より好ましくは０．０１μｍ以上１μｍ以下、さらに好ましくは０．０５μｍ以上０．５μｍ以下である。 If desired, the positive electrode current collector 20 may include a carbon film on the surface on the solid electrolyte layer 14 side. By carrying out like this, the electronic conductivity of the positive electrode electrical power collector 20 and the orientation positive electrode plate 12 can be improved, and the contact resistance in an interface can be reduced further. The thickness of the carbon film is preferably 0.01 μm to 5 μm, more preferably 0.01 μm to 1 μm, and still more preferably 0.05 μm to 0.5 μm.
　配向正極板
　配向正極板１２は配向焼結体からなる厚さ２０μｍ以上の自立した板である。配向焼結体は層状岩塩構造を有するリチウム複合酸化物で構成される複数の結晶粒を含む。リチウム複合酸化物は、ＬｉｘＭＯ２（０．０５＜ｘ＜１．１０であり、Ｍは少なくとも１種類の遷移金属であり、Ｍは典型的にはＣｏ、Ｎｉ及びＭｎから選択される１種以上を含む）で表される酸化物である。リチウム複合酸化物は、典型的には層状岩塩構造を有する。層状岩塩構造とは、リチウム層とリチウム以外の遷移金属層とが酸素の層を挟んで交互に積層された結晶構造、すなわち、酸化物イオンを介して遷移金属イオン層とリチウム単独層とが交互に積層した結晶構造（典型的には、α－ＮａＦｅＯ２型構造、すなわち立方晶岩塩型構造の［１１１］軸方向に遷移金属とリチウムとが規則配列した構造）をいう。リチウム複合酸化物の例としては、コバルト酸リチウム、ニッケル酸リチウム、マンガン酸リチウム、ニッケル・マンガン酸リチウム、ニッケル・コバルト酸リチウム、コバルト・ニッケル・マンガン酸リチウム、コバルト・マンガン酸リチウムなどが挙げられる。リチウム複合酸化物には、Ｍｇ，Ａｌ，Ｓｉ，Ｃａ，Ｔｉ，Ｖ，Ｃｒ，Ｆｅ，Ｃｕ，Ｚｎ，Ｇａ，Ｇｅ，Ｓｒ，Ｙ，Ｚｒ，Ｎｂ，Ｍｏ，Ａｇ，Ｓｎ，Ｓｂ，Ｔｅ，Ｂａ，Ｂｉ、Ｗ等から選択される一種以上の元素が含まれていてもよい。特に好ましいリチウム複合酸化物はコバルト酸リチウムである。すなわち、結晶粒がコバルト酸リチウム結晶粒であるのが特に好ましい。 Oriented positive electrode plate The oriented positive electrode plate 12 is a self-supporting plate made of an oriented sintered body and having a thickness of 20 μm or more. The oriented sintered body includes a plurality of crystal grains composed of a lithium composite oxide having a layered rock salt structure. The lithium composite oxide is Li x MO 2 (0.05 <x <1.10, M is at least one transition metal, and M is typically selected from Co, Ni, and Mn. Oxide containing a species or more). The lithium composite oxide typically has a layered rock salt structure. The layered rock salt structure is a crystal structure in which lithium layers and transition metal layers other than lithium are alternately stacked with oxygen layers in between, that is, the transition metal ion layers and lithium single layers are alternately arranged via oxide ions. (Typically an α-NaFeO 2 type structure, ie, a structure in which transition metals and lithium are regularly arranged in the [111] axis direction of a cubic rock salt type structure). Examples of lithium composite oxides include lithium cobaltate, lithium nickelate, lithium manganate, nickel / lithium manganate, nickel / lithium cobaltate, cobalt / nickel / lithium manganate, cobalt / lithium manganate, etc. . The lithium composite oxide includes Mg, Al, Si, Ca, Ti, V, Cr, Fe, Cu, Zn, Ga, Ge, Sr, Y, Zr, Nb, Mo, Ag, Sn, Sb, Te, Ba. , Bi, W, etc. may contain one or more elements. A particularly preferable lithium composite oxide is lithium cobalt oxide. That is, it is particularly preferable that the crystal grains are lithium cobalt oxide crystal grains.
　配向焼結体に含まれる複数の結晶粒は、（００３）面が配向正極板の板面に対して平行に配向している。配向焼結体に含まれる結晶粒の全て平行である必要はないが、それらの大部分が平行であるのが好ましい。ここで、本明細書において「平行」とは完全な平行（すなわち０度）に限られるものではなく、略平行ともいうべき平行に準ずる角度も包含するものであり、典型的には板面と（００３）面がなす角度が３０度以内、より典型的には２５度以内、さらに典型的には２０度以内、特に典型的には１５度以内、特に典型的には１０度以内、最も典型的には５度以内を意味するものとする。層状岩塩構造のリチウム複合酸化物は、リチウムイオンが抜けるのに伴い、層間距離が広がる性質がある。すなわち、図５に概念的に示されるように一次粒子としてのリチウム複合酸化物結晶粒１１は（００３）面と平行にリチウムイオン移動方向ＬｉＤを有するとともに、（００３）面と垂直に膨張収縮方向ＥＣＤを有している。したがって、図６に示されるように、（００３）面が板面に対して非平行に（すなわち斜め又は垂直に）配向した従来の配向正極板１２’においては、複数個のリチウム複合酸化物結晶粒１１の膨張収縮が、全体として配向正極板１２’の板面と平行方向の膨張収縮をもたらす、すなわち膨張収縮方向ＥＣＤが板面と平行となる。これに対し、本発明で採用される配向正極板１２は、図７の破断面ＳＥＭ画像に例示され且つ図８に概念的に描かれるように、（００３）面が板面と平行となることで、リチウムイオンが抜けることに伴う配向正極板１２の面方向の膨張が小さくなる。このため、充放電時における配向正極板１２の膨張収縮による固体電解質層１４への引張応力が低減され、固体電解質層１４の破損や剥がれ、クラック発生等による電気的なショートや抵抗増加を防止することができ、サイクル特性の向上につながる。なお、図８は、リチウムイオン移動方向ＬｉＤを簡潔に描くため、図７に示されるものよりも結晶粒１１の角度を大きめに描いてあるが、結晶粒１１が図７と同程度の平行を意味するものとして理解されるべきである。いずれにしても、図８に示されるリチウム移動方向ＬｉＤから理解されるように、本発明で採用される配向正極板１２においてはリチウムイオン移動距離が、図６に示される従来の配向正極板１２’のリチウムイオン移動距離よりも格段に長くなる。それにもかかわらずレート特性及びサイクル特性といった電池特性は良好であり、このことは全く予想外ともいうべき驚くべき知見に他ならない。 The (003) plane of the plurality of crystal grains contained in the oriented sintered body is oriented parallel to the plate surface of the oriented positive electrode plate. It is not necessary for all of the crystal grains contained in the oriented sintered body to be parallel, but most of them are preferably parallel. Here, in this specification, “parallel” is not limited to perfect parallel (that is, 0 degree), but includes an angle equivalent to parallel, which should be substantially parallel. The angle formed by the (003) plane is within 30 degrees, more typically within 25 degrees, even more typically within 20 degrees, particularly typically within 15 degrees, particularly typically within 10 degrees, most typically Specifically, it means within 5 degrees. The layered rock salt structure lithium composite oxide has the property that the interlayer distance increases as lithium ions are released. That is, as conceptually shown in FIG. 5, the lithium composite oxide crystal grains 11 as primary particles have a lithium ion movement direction LiD parallel to the (003) plane, and the expansion / contraction direction perpendicular to the (003) plane. Has ECD. Therefore, as shown in FIG. 6, in the conventional oriented positive electrode plate 12 ′ in which the (003) plane is oriented non-parallel to the plate surface (ie, obliquely or vertically), a plurality of lithium composite oxide crystals The expansion / contraction of the grains 11 results in expansion / contraction in the direction parallel to the plate surface of the oriented positive electrode plate 12 ′ as a whole, that is, the expansion / contraction direction ECD is parallel to the plate surface. In contrast, the oriented positive electrode plate 12 employed in the present invention has the (003) plane parallel to the plate surface as illustrated in the fracture surface SEM image of FIG. 7 and conceptually depicted in FIG. Thus, the expansion in the surface direction of the aligned positive electrode plate 12 accompanying the release of lithium ions is reduced. For this reason, the tensile stress to the solid electrolyte layer 14 due to the expansion and contraction of the oriented positive electrode plate 12 at the time of charging / discharging is reduced, and an electrical short circuit or an increase in resistance due to the breakage or peeling of the solid electrolyte layer 14 or the occurrence of cracks is prevented. Can lead to improved cycle characteristics. 8 shows the lithium ion movement direction LiD in a concise manner, the angle of the crystal grain 11 is drawn larger than that shown in FIG. 7, but the crystal grain 11 is parallel to the same degree as in FIG. It should be understood as meaning. In any case, as understood from the lithium moving direction LiD shown in FIG. 8, in the aligned positive electrode plate 12 employed in the present invention, the lithium ion moving distance is the same as that of the conventional aligned positive electrode plate 12 shown in FIG. It is much longer than the lithium ion movement distance. Nevertheless, battery characteristics such as rate characteristics and cycle characteristics are good, and this is a surprising finding that is totally unexpected.
　配向焼結体に含まれる個々の結晶粒の配向方位は電子線後方散乱回折（ＥＢＳＤ）により解析することができる。図９Ａに配向正極板の板面に垂直な断面の一例を示すＳＥＭ像を、図９Ｂに図９Ａにおいて四角形の枠で特定される測定領域における、配向正極板の断面のＥＢＳＤ像を示す。図９Ｂに示されるＥＢＳＤ像では、結晶方位の不連続性を観測することができる。図９Ｂでは、各結晶粒（一次粒子）の配向角度が色の濃淡で表されており、色が濃いほど配向角度が小さいことを示している。配向角度とは、各結晶粒の（００３）面が板面方向に対して成す傾斜角度である。なお、図９Ａ及び９Ｂにおいて、配向正極板の内部で黒く表示されている箇所は気孔である。 The orientation orientation of individual crystal grains contained in the oriented sintered body can be analyzed by electron beam backscatter diffraction (EBSD). FIG. 9A shows an SEM image showing an example of a cross section perpendicular to the plate surface of the oriented positive electrode plate, and FIG. 9B shows an EBSD image of a cross section of the oriented positive electrode plate in the measurement region specified by the rectangular frame in FIG. 9A. In the EBSD image shown in FIG. 9B, discontinuity of crystal orientation can be observed. In FIG. 9B, the orientation angle of each crystal grain (primary particle) is represented by color shading, and the darker the color, the smaller the orientation angle. The orientation angle is an inclination angle formed by the (003) plane of each crystal grain with respect to the plate surface direction. In FIGS. 9A and 9B, the portions displayed in black inside the oriented positive plate are pores.
　図９Ａ及び９Ｂに示されように、結晶粒（一次粒子）の配向角度の平均値（以下、「平均配向角度」という）は、０°超３０°以下である。結晶粒ないし一次粒子の平均配向角度は、図９Ｂに示されるような、配向正極板の断面におけるＥＢＳＤ像において、後述の方法で選択した３０個程度の一次粒子の配向角度を算術平均することによって得られる。一次粒子の平均配向角度は、レート特性をより向上させることを考慮すると、３０°以下が好ましく、２５°以下がより好ましい。一次粒子の平均配向角度は、同様にレート特性を考慮すると、２°以上が好ましく、５°以上がより好ましい。ここで、平均配向度の算出に用いる一次粒子は、正極板断面におけるＥＢＳＤ像において、像内に３０個程度の一次粒子が含まれるような観察倍率を設定したときに、像内に一次粒子の外周が完全に含まれる、全ての粒子とする。なお、最大フェレー径が０．５μｍ未満の一次粒子は算入しないものとする。 9A and 9B, the average value of the orientation angles of crystal grains (primary particles) (hereinafter referred to as “average orientation angle”) is more than 0 ° and not more than 30 °. The average orientation angle of crystal grains or primary particles is obtained by arithmetically averaging the orientation angles of about 30 primary particles selected by the method described later in the EBSD image in the cross section of the orientation positive electrode plate as shown in FIG. 9B. can get. The average orientation angle of the primary particles is preferably 30 ° or less and more preferably 25 ° or less in consideration of further improving the rate characteristics. Similarly, the average orientation angle of the primary particles is preferably 2 ° or more, more preferably 5 ° or more, considering rate characteristics. Here, the primary particles used for calculation of the average degree of orientation are those of the primary particles in the image when the observation magnification is set such that about 30 primary particles are included in the image in the EBSD image in the cross section of the positive electrode plate. All the particles whose outer periphery is completely included are included. Note that primary particles having a maximum ferret diameter of less than 0.5 μm are not counted.
　好ましくは、配向焼結体１２の断面を電子線後方散乱回折法（ＥＢＳＤ）により解析した場合に、解析された断面に含まれる結晶粒のうち板面に対する（００３）面の角度が０°超３０°以下である結晶粒の合計面積が、断面に含まれる結晶粒の総面積に対して７０％以上である。すなわち、図９Ｂに示されるようなＥＢＳＤ像において、配向角度が０°超３０°以下である一次粒子（以下、「低角一次粒子」という。）の合計面積は、平均配向角度の算出に用いた一次粒子の総面積に対して７０％以上であることが好ましい。これによって、相互密着性の高い一次粒子の割合を増加させることができるため、レート特性をより向上させることができる。低角一次粒子の合計面積は、レート特性をより向上させることを考慮すると、平均配向角度の算出に用いた３０個程度の一次粒子の総面積に対して、７０％超がより好ましく、８０％以上がより好ましい。また、低角一次粒子のうち配向角度が２０°以下であるものの合計面積は、平均配向角度の算出に用いた３０個程度の一次粒子の総面積に対して５０％以上であることがより好ましい。さらに、低角一次粒子のうち配向角度が１０°以下であるものの合計面積は、平均配向角度の算出に用いた３０個の一次粒子の総面積に対して１５％以上であることがより好ましい。 Preferably, when the cross section of the oriented sintered body 12 is analyzed by electron beam backscatter diffraction (EBSD), the angle of the (003) plane with respect to the plate surface among the crystal grains included in the analyzed cross section exceeds 0 °. The total area of crystal grains of 30 ° or less is 70% or more with respect to the total area of crystal grains included in the cross section. That is, in the EBSD image as shown in FIG. 9B, the total area of primary particles whose orientation angle is greater than 0 ° and 30 ° or less (hereinafter referred to as “low angle primary particles”) is used for calculating the average orientation angle. The total area of the primary particles is preferably 70% or more. As a result, the ratio of primary particles having high mutual adhesion can be increased, so that the rate characteristics can be further improved. In consideration of further improving the rate characteristics, the total area of the low-angle primary particles is preferably more than 70%, more preferably 80% with respect to the total area of about 30 primary particles used for calculating the average orientation angle. The above is more preferable. The total area of the low-angle primary particles having an orientation angle of 20 ° or less is more preferably 50% or more with respect to the total area of about 30 primary particles used for calculation of the average orientation angle. . Further, the total area of the low-angle primary particles having an orientation angle of 10 ° or less is more preferably 15% or more with respect to the total area of 30 primary particles used for calculating the average orientation angle.
　配向正極板１２の厚さは、単位面積当りの活物質容量を高くし、かつ、基材フリーの自立した形態を確保する観点から、好ましくは２０μｍ以上であり、より好ましくは３０μｍ以上であり、さらに好ましくは４０μｍ以上、特に好ましくは５０μｍ以上、最も好ましくは５５μｍ以上である。厚さの上限値は、充放電の繰り返しに伴う電池特性の劣化（特に抵抗値の上昇）を低減する観点から、好ましくは１００μｍ以下、より好ましくは９０μｍ以下、さらに好ましくは８０μｍ以下、特に好ましくは７０μｍ以下である。また、配向正極板のサイズは、好ましくは５ｍｍ×５ｍｍ平方以上、より好ましくは１０ｍｍ×１０ｍｍ～１００ｍｍ×１００ｍｍ平方であり、さらに好ましくは２０ｍｍ×２０ｍｍ～２００ｍｍ×２００ｍｍ平方であり、別の表現をすれば、好ましくは２５ｍｍ２以上、より好ましくは１００～１００００ｍｍ２であり、さらに好ましくは４００～４００００ｍｍ２である。 The thickness of the alignment positive electrode plate 12 is preferably 20 μm or more, more preferably 30 μm or more, from the viewpoint of increasing the active material capacity per unit area and ensuring a self-supporting form free of a substrate. More preferably, it is 40 μm or more, particularly preferably 50 μm or more, and most preferably 55 μm or more. The upper limit of the thickness is preferably 100 μm or less, more preferably 90 μm or less, still more preferably 80 μm or less, and particularly preferably from the viewpoint of reducing deterioration of battery characteristics (particularly increase in resistance value) due to repeated charge / discharge. 70 μm or less. Further, the size of the oriented positive electrode plate is preferably 5 mm × 5 mm square or more, more preferably 10 mm × 10 mm to 100 mm × 100 mm square, and further preferably 20 mm × 20 mm to 200 mm × 200 mm square. if, preferably 25 mm 2 or more, more preferably 100 ~ 10000 mm 2, more preferably from 400 ~ 40000 mm 2.
　前述のとおり、結晶粒はコバルト酸リチウム結晶粒であるのが好ましい。コバルト酸リチウム結晶粒を構成するＬｉＣｏＯ２は層状岩塩構造を有するものであるが、本発明に用いる配向焼結板は、典型的には、コバルト酸リチウムの（００３）面が配向正極板の板面と平行に配向しているものである。このことは、板面のＸＲＤプロファイルをとったときの、（００３）面による回折ピーク強度の、（１０４）面による回折ピーク強度に対する比が、粉砕粉のＸＲＤプロファイルのそれに対し、大きくなっていることで判断できる。もっとも、コバルト酸リチウム配向焼結板は、本発明の趣旨を逸脱しない範囲内において、Ｍｇ，Ａｌ，Ｓｉ，Ｃａ，Ｔｉ，Ｖ，Ｃｒ，Ｆｅ，Ｃｕ，Ｚｎ，Ｇａ，Ｇｅ，Ｓｒ，Ｙ，Ｚｒ，Ｎｂ，Ｍｏ，Ａｇ，Ｓｎ，Ｓｂ，Ｔｅ，Ｂａ，Ｂｉ等の元素が１種以上更にドーピング又はそれに準ずる形態（例えば結晶粒子の表層への部分的な固溶、偏析、コーティング、又は付着）で微量含んでいてもよい。 As described above, the crystal grains are preferably lithium cobaltate crystal grains. LiCoO 2 constituting the lithium cobaltate crystal grains has a layered rock salt structure, but the oriented sintered plate used in the present invention is typically a plate in which the (003) plane of lithium cobaltate is an oriented positive plate. It is oriented parallel to the surface. This is because the ratio of the diffraction peak intensity due to the (003) plane to the diffraction peak intensity due to the (104) plane when taking the XRD profile of the plate surface is larger than that of the XRD profile of the pulverized powder. Can be judged. However, the lithium cobalt oxide oriented sintered plate is Mg, Al, Si, Ca, Ti, V, Cr, Fe, Cu, Zn, Ga, Ge, Sr, Y, and the like within the scope of the present invention. One or more elements such as Zr, Nb, Mo, Ag, Sn, Sb, Te, Ba, Bi, etc. are further doped or equivalent (for example, partial solid solution, segregation, coating, or adhesion to the surface layer of crystal grains) ) May contain a trace amount.
　配向正極板１２を構成する焼結体の緻密度は９０％以上であるのが好ましく、より好ましくは９０～９８％、さらに好ましくは９２～９８％、特に好ましくは９２～９５％である。緻密度は、焼結体の嵩密度をアルキメデス法で測定し、嵩密度を真密度で除することにより、算出することができる。あるいは、上記緻密度は、配向正極板１２の断面をＣＰ研磨した後に１０００倍率でＳＥＭ観察して、得られたＳＥＭ画像を２値化することで算出してもよい。容量及びエネルギー密度の観点から緻密度は基本的には高い方が望ましいが、上記範囲内であると充放電の繰り返しによっても抵抗値が上昇しにくい。これは上記緻密度であるとリチウムの脱挿入に伴い配向正極板１２が適度に膨張収縮でき、それにより応力を緩和できるためではないかと考えられる。 The density of the sintered body constituting the oriented positive electrode plate 12 is preferably 90% or more, more preferably 90 to 98%, still more preferably 92 to 98%, and particularly preferably 92 to 95%. The density can be calculated by measuring the bulk density of the sintered body by the Archimedes method and dividing the bulk density by the true density. Alternatively, the density may be calculated by performing SEM observation at 1000 magnifications after CP polishing of the cross section of the aligned positive electrode plate 12, and binarizing the obtained SEM image. From the viewpoint of capacity and energy density, it is basically desirable that the density be high, but if it is within the above range, the resistance value is unlikely to increase even after repeated charge and discharge. It is considered that this is because the dense positive electrode plate 12 can be appropriately expanded and contracted as lithium is deinserted and the stress can be relaxed.
　配向正極板１２は、固体電解質層１４と反対側の面（正極集電体２０側の面）に、厚さ０．０１μｍ以上５μｍ未満の導電膜１２ａを備えるのが好ましい。こうすることで、正極集電体２０と配向正極板１２との電子伝導性を高め、界面における接触抵抗をより一層低減することができる。導電膜１２ａは金属及び／又はカーボンで構成されるのが好ましい。導電膜１２ａは、金属で構成される場合、正極集電体２０及び配向正極板１２との電子伝導抵抗が低く、しかも配向正極板１２の特性への悪影響の無い金属からなる層であれば特に限定されないが、好ましい例としてはＡｕスパッタ層及びＳｉスパッタ層が挙げられる。また、Ａｕスパッタ層等の金属製導電膜の代わりにカーボン層を用いてもよい。導電膜１２ａの厚さは０．０１μｍ以上５μｍ未満であり、好ましくは０．０２μｍ以上２μｍ以下、より好ましくは０．０２μｍ以上１μｍ以下、さらに好ましくは０．０４μｍ以上１μｍ以下である。 The oriented positive electrode plate 12 is preferably provided with a conductive film 12a having a thickness of 0.01 μm or more and less than 5 μm on the surface opposite to the solid electrolyte layer 14 (surface on the positive electrode current collector 20 side). By carrying out like this, the electronic conductivity of the positive electrode electrical power collector 20 and the orientation positive electrode plate 12 can be improved, and the contact resistance in an interface can be reduced further. The conductive film 12a is preferably made of metal and / or carbon. When the conductive film 12a is made of a metal, the conductive film 12a has a low electron conduction resistance with the positive electrode current collector 20 and the alignment positive electrode plate 12 and is a layer made of a metal that does not adversely affect the characteristics of the alignment positive electrode plate 12, in particular. Although not limited, preferred examples include an Au sputtered layer and a Si sputtered layer. A carbon layer may be used instead of a metal conductive film such as an Au sputter layer. The thickness of the conductive film 12a is 0.01 μm or more and less than 5 μm, preferably 0.02 μm or more and 2 μm or less, more preferably 0.02 μm or more and 1 μm or less, and further preferably 0.04 μm or more and 1 μm or less.
　固体電解質層
　固体電解質層１４を構成するリチウムイオン伝導材料は、ガーネット系セラミックス材料、窒化物系セラミックス材料、ペロブスカイト系セラミックス材料、リン酸系セラミックス材料、硫化物系セラミックス材料、又は高分子系材料で構成されるのが好ましく、より好ましくは、ガーネット系セラミックス材料、窒化物系セラミックス材料、ペロブスカイト系セラミックス材料、及びリン酸系セラミックス材料からなる群から選択される少なくとも一種である。ガーネット系セラミックス材料の例としては、Ｌｉ－Ｌａ－Ｚｒ－Ｏ系材料（具体的には、Ｌｉ７Ｌａ３Ｚｒ２Ｏ１２など）、Ｌｉ－Ｌａ－Ｔａ－Ｏ系材料（具体的には、Ｌｉ７Ｌａ３Ｔａ２Ｏ１２など）が挙げられる。窒化物系セラミックス材料の例としては、Ｌｉ３Ｎ。ペロブスカイト系セラミックス材料の例としては、Ｌｉ－Ｌａ－Ｚｒ－Ｏ系材料（具体的には、ＬｉＬａ１－ｘＴｉｘＯ３（０．０４≦ｘ≦０．１４）など）が挙げられる。リン酸系セラミックス材料の例としては、リン酸リチウム、窒素置換リン酸リチウム（ＬｉＰＯＮ）、Ｌｉ－Ａｌ－Ｔｉ－Ｐ－Ｏ，Ｌｉ－Ａｌ－Ｇｅ－Ｐ－Ｏ、及びＬｉ－Ａｌ－Ｔｉ－Ｓｉ－Ｐ－Ｏ（具体的には、Ｌｉ１＋ｘ＋ｙＡｌｘＴｉ２－ｘＳｉｙＰ３－ｙＯ１２（０≦ｘ≦０．４、０＜ｙ≦０．６）など）が挙げられる。 The lithium ion conductive material constituting the solid electrolyte layer 14 is a garnet ceramic material, a nitride ceramic material, a perovskite ceramic material, a phosphate ceramic material, a sulfide ceramic material, or a polymer material. Preferably, it is at least one selected from the group consisting of garnet-based ceramic materials, nitride-based ceramic materials, perovskite-based ceramic materials, and phosphate-based ceramic materials. Examples of garnet based ceramic materials include Li—La—Zr—O based materials (specifically, Li 7 La 3 Zr 2 O 12 etc.), Li—La—Ta—O based materials (specifically, Li 7 La 3 Ta 2 O 12 etc.). An example of a nitride ceramic material is Li 3 N. Examples of perovskite ceramic materials include Li—La—Zr—O based materials (specifically, LiLa 1-x Ti x O 3 (0.04 ≦ x ≦ 0.14), etc.). Examples of phosphate ceramic materials include lithium phosphate, nitrogen-substituted lithium phosphate (LiPON), Li—Al—Ti—PO, Li—Al—Ge—PO, and Li—Al—Ti—. Si—P—O (specifically, Li 1 + x + y Al x Ti 2−x Si y P 3−y O 12 (0 ≦ x ≦ 0.4, 0 <y ≦ 0.6), etc.) may be mentioned.
　固体電解質層１４を構成するリチウムイオン伝導材料が、Ｌｉ－Ｌａ－Ｚｒ－Ｏ系セラミックス材料及び／又はリン酸リチウムオキシナイトライド（ＬｉＰＯＮ）系セラミックス材料で構成されるのが特に好ましい。Ｌｉ－Ｌａ－Ｚｒ－Ｏ系材料は、Ｌｉ、Ｌａ、Ｚｒ及びＯを含んで構成されるガーネット型又はガーネット型類似の結晶構造を有する酸化物焼結体であり、具体的には、Ｌｉ７Ｌａ３Ｚｒ２Ｏ１２などのガーネット系セラミックス材料である。ガーネット系セラミックス材料は、負極リチウムと直接接触しても反応が起きないリチウムイオン伝導材料であるが、とりわけ、Ｌｉ、Ｌａ、Ｚｒ及びＯを含んで構成されるガーネット型又はガーネット型類似の結晶構造を有する酸化物焼結体が、焼結性に優れて緻密化しやすく、かつ、イオン伝導率も高い。この種の組成のガーネット型又はガーネット型類似の結晶構造はＬＬＺ結晶構造と呼ばれ、ＣＳＤ（Ｃａｍｂｒｉｄｇｅ　Ｓｔｒｕｃｔｕｒａｌ　Ｄａｔａｂａｓｅ）のＸ線回折ファイルＮｏ．４２２２５９（Ｌｉ７Ｌａ３Ｚｒ２Ｏ１２）に類似のＸＲＤパターンを有する。なお、Ｎｏ．４２２２５９と比較すると構成元素が異なり、またセラミックス中のＬｉ濃度などが異なる可能性があるため、回折角度や回折強度比が異なる場合もある。Ｌａに対するＬｉのモル数の比Ｌｉ／Ｌａは２．０以上２．５以下であることが好ましく、Ｌａに対するＺｒのモル比Ｚｒ／Ｌａは０．５以上０．６７以下であるのが好ましい。このガーネット型又はガーネット型類似の結晶構造はＮｂ及び／又はＴａをさらに含んで構成されるものであってもよい。すなわち、ＬＬＺのＺｒの一部がＮｂ及びＴａのいずれか一方又は双方で置換されることにより、置換前に比べて伝導率を向上させることができる。ＺｒのＮｂ及び／又はＴａによる置換量（モル比）は、（Ｎｂ＋Ｔａ）／Ｌａのモル比が０．０３以上０．２０以下となる量にすることが好ましい。また、このガーネット系酸化物焼結体はＡｌをさらに含んでいるのが好ましく、これらの元素は結晶格子に存在してもよいし、結晶格子以外に存在していてもよい。Ａｌの添加量は焼結体の０．０１～１質量％とするのが好ましく、Ｌａに対するＡｌのモル比Ａｌ／Ｌａは、０．００８～０．１２であるのが好ましい。このようなＬＬＺ系セラミックスの製造は、公知の手法に従って又はそれを適宜修正することにより行うことができる。また、リン酸リチウムオキシナイトライド（ＬｉＰＯＮ）系セラミックス材料も好ましい。ＬｉＰＯＮは、Ｌｉ２．９ＰＯ３．３Ｎ０．４６の組成によって代表されるような化合物群であり、例えばＬｉａＰＯｂＮｃ（式中、ａは２～４、ｂは３～５、ｃは０．１～０．９である）で表される化合物群である。 It is particularly preferable that the lithium ion conductive material constituting the solid electrolyte layer 14 is composed of a Li—La—Zr—O based ceramic material and / or a lithium phosphate oxynitride (LiPON) based ceramic material. The Li—La—Zr—O-based material is an oxide sintered body having a garnet-type or garnet-type similar crystal structure including Li, La, Zr, and O. Specifically, Li 7 A garnet-based ceramic material such as La 3 Zr 2 O 12 . The garnet-based ceramic material is a lithium ion conductive material that does not react even when directly contacted with the negative electrode lithium, and in particular, a garnet-type or garnet-type similar crystal structure including Li, La, Zr, and O Oxide sintered bodies having excellent sinterability and easy densification and high ionic conductivity. A garnet-type or garnet-like crystal structure having this kind of composition is called an LLZ crystal structure, which is referred to as CSD (Cambridge Structure Database) X-ray diffraction file No. It has an XRD pattern similar to 422259 (Li 7 La 3 Zr 2 O 12 ). In addition, No. Compared to 422259, the constituent elements are different and the Li concentration in the ceramics may be different, so the diffraction angle and the diffraction intensity ratio may be different. The molar ratio Li / La of Li to La is preferably 2.0 or more and 2.5 or less, and the molar ratio Zr / La to La is preferably 0.5 or more and 0.67 or less. This garnet-type or garnet-like crystal structure may further comprise Nb and / or Ta. That is, by replacing a part of Zr of LLZ with one or both of Nb and Ta, the conductivity can be improved as compared with that before the substitution. The substitution amount (molar ratio) of Zr with Nb and / or Ta is preferably set such that the molar ratio of (Nb + Ta) / La is 0.03 or more and 0.20 or less. The garnet-based oxide sintered body preferably further contains Al, and these elements may exist in the crystal lattice or may exist in other than the crystal lattice. The amount of Al added is preferably 0.01 to 1% by mass of the sintered body, and the molar ratio Al / La to La is preferably 0.008 to 0.12. Such LLZ-based ceramics can be manufactured according to a known method or by appropriately modifying it. A lithium phosphate oxynitride (LiPON) ceramic material is also preferable. LiPON is a group of compounds represented by the composition of Li 2.9 PO 3.3 N 0.46 . For example, Li a PO b N c (wherein a is 2 to 4 and b is 3 to 5 , C is 0.1 to 0.9).
　固体電解質層１４の寸法は特に限定されないが、厚さは充放電レート特性と機械的強度の観点から、０．０００５ｍｍ～０．１ｍｍが好ましく、より好ましくは０．００１ｍｍ～０．０５ｍｍ、さらに好ましくは０．００２～０．０２ｍｍ、特に好ましくは０．００３～０．０１ｍｍである。 The dimensions of the solid electrolyte layer 14 are not particularly limited, but the thickness is preferably 0.0005 mm to 0.1 mm, more preferably 0.001 mm to 0.05 mm, and still more preferably, from the viewpoint of charge / discharge rate characteristics and mechanical strength. Is 0.002 to 0.02 mm, particularly preferably 0.003 to 0.01 mm.
　固体電解質層１４の形成方法としては、各種パーティクルジェットコーティング法、固相法、溶液法、気相法を用いることができる。パーティクルジェットコーティング法の例としては、エアロゾルデポジション（ＡＤ）法、ガスデポジション（ＧＤ）法、パウダージェットデポジション（ＰＪＤ）法、コールドスプレー（ＣＳ）法、溶射法等がある。中でも、エアロゾルデポジション（ＡＤ）法は、常温成膜が可能であることから、プロセス中の組成ズレや、配向正極板との反応による高抵抗層の形成がなく特に好ましい。固相法の例としては、テープ積層法、印刷法等がある。中でも、テープ積層法は固体電解質層１４を薄く形成することが可能であり、また、厚さの制御が容易であることから好ましい。溶液法の例としては、ソルボサーマル法、水熱合成法、ゾルゲル法、沈殿法、マイクロエマルション法、溶媒蒸発法等がある。これらの方法の中でも、水熱合成法は、低温で結晶性の高い結晶粒を得やすい点で特に好ましい。また、これらの方法を用いて合成した微結晶を、正極上に堆積させてもよいし、正極上に直接析出させてもよい。気相法の例としては、レーザー堆積（ＰＬＤ）法、スパッタリング法、蒸発凝縮（ＰＶＤ）法、気相反応法（ＣＶＤ）法、真空蒸着法、分子線エピタキシ（ＭＢＥ）法等がある。この中でも、スパッタリング法は組成ズレが少なく、比較的密着性の高い膜を得られやすく特に好ましい。 As a method for forming the solid electrolyte layer 14, various particle jet coating methods, solid phase methods, solution methods, and gas phase methods can be used. Examples of the particle jet coating method include an aerosol deposition (AD) method, a gas deposition (GD) method, a powder jet deposition (PJD) method, a cold spray (CS) method, and a thermal spraying method. Among these, the aerosol deposition (AD) method is particularly preferable because it can form a film at room temperature, and does not cause a composition shift in the process or formation of a high resistance layer by reaction with an oriented positive electrode plate. Examples of the solid phase method include a tape lamination method and a printing method. Among these, the tape lamination method is preferable because the solid electrolyte layer 14 can be formed thin and the thickness can be easily controlled. Examples of the solution method include a solvothermal method, a hydrothermal synthesis method, a sol-gel method, a precipitation method, a microemulsion method, and a solvent evaporation method. Among these methods, the hydrothermal synthesis method is particularly preferable in that it is easy to obtain crystal grains having high crystallinity at a low temperature. In addition, microcrystals synthesized using these methods may be deposited on the positive electrode or may be directly deposited on the positive electrode. Examples of the gas phase method include laser deposition (PLD) method, sputtering method, evaporation condensation (PVD) method, gas phase reaction method (CVD) method, vacuum deposition method, molecular beam epitaxy (MBE) method and the like. Among these, the sputtering method is particularly preferable because there is little composition deviation and a film with relatively high adhesion can be easily obtained.
　配向正極板１２と固体電解質層１４の間の界面には界面抵抗を下げるための処理が施されていてもよい。例えば、そのような処理は、ニオブ酸化物、チタン酸化物、タングステン酸化物、タンタル酸化物、リチウム・ニッケル複合酸化物、リチウム・チタン複合酸化物、リチウム・ニオブ化合物、リチウム・タンタル化合物、リチウム・タングステン化合物、リチウム・チタン化合物、及びこれらの任意の組み合わせ若しくは複合酸化物で配向正極板１２の表面及び／又は固体電解質層１４の表面を被覆することにより行うことができる。このような処理によって配向正極板１２と固体電解質層１４の間の界面には被膜が存在しうることになるが、その被膜の厚さは例えば２０ｎｍ以下といったような極めて薄いものである。 The interface between the oriented positive electrode plate 12 and the solid electrolyte layer 14 may be subjected to a treatment for reducing the interface resistance. For example, such treatment includes niobium oxide, titanium oxide, tungsten oxide, tantalum oxide, lithium-nickel composite oxide, lithium-titanium composite oxide, lithium-niobium compound, lithium-tantalum compound, lithium- This can be done by coating the surface of the oriented positive electrode plate 12 and / or the surface of the solid electrolyte layer 14 with a tungsten compound, a lithium / titanium compound, and any combination or composite oxide thereof. By such treatment, a coating film can exist at the interface between the oriented positive electrode plate 12 and the solid electrolyte layer 14, but the thickness of the coating film is extremely thin, for example, 20 nm or less.
　負極層
　負極層１６はリチウムを含む層であり、典型的にはリチウム金属により構成される。負極層１６は、固体電解質層１４又は負極集電体２４上に箔形態のリチウム金属を載置することにより作製してもよいし、あるいは固体電解質層１４または負極集電体２４上にリチウム金属の薄膜を真空蒸着法、スパッタリング法、ＣＶＤ法等で形成してリチウム金属の層を形成することにより作製することができる。 Negative electrode layer The negative electrode layer 16 is a layer containing lithium and is typically composed of lithium metal. The negative electrode layer 16 may be formed by placing lithium metal in the form of a foil on the solid electrolyte layer 14 or the negative electrode current collector 24, or may be formed on the solid electrolyte layer 14 or the negative electrode current collector 24. The thin film can be formed by a vacuum deposition method, a sputtering method, a CVD method, or the like to form a lithium metal layer.
　負極層１６の寸法は特に限定されないが、厚さは、厚い配向正極板１２の採用に伴い全固体リチウム電池１０におけるリチウム総量を多く確保する観点から、１０μｍ以上が好ましく、より好ましくは５０～１０μｍ、さらに好ましくは４０～１０μｍ、特に好ましくは２０～１０μｍである。 The dimensions of the negative electrode layer 16 are not particularly limited, but the thickness is preferably 10 μm or more, more preferably 50 to 10 μm, from the viewpoint of securing a large amount of lithium in the all-solid lithium battery 10 with the adoption of the thick oriented positive electrode plate 12. More preferably, it is 40 to 10 μm, particularly preferably 20 to 10 μm.
　中間層
　所望により、負極層１６と固体電解質層１４の間に中間層を介在させてもよい。すなわち、全固体リチウム電池１０は、固体電解質層１４の負極層１６側の面にリチウムと合金化可能な金属を含む中間層をさらに含むことができる。中間層の構成材料としては、リチウムと合金化する金属、酸化物系材料等を用いることができる。こうすることで、リフローはんだ付けプロセス等の加熱を伴うプロセス（例えば２００℃以上の温度で行われるプロセス）に付されても、リチウム金属の融け出し等が有意に抑制され、それ故、内部短絡や負極層の剥離を効果的に防止することができる。また、充放電サイクル特性を向上させることができる。リチウムと合金化可能な金属は、Ａｌ（アルミニウム）、Ｓｉ（シリコン）、Ｚｎ（亜鉛）、Ｇａ（ガリウム）、Ｇｅ（ゲルマニウム）、Ａｇ（銀）、Ａｕ（金）、Ｐｔ（白金）、Ｃｄ（カドミウム）、Ｉｎ（インジウム）、Ｓｎ（スズ）、Ｓｂ（アンチモン）、Ｐｂ（鉛）、及びＢｉ（ビスマス）からなる群から選択される少なくとも１種を含むのが好ましく、より好ましくはＡｕ（金）、Ｉｎ（インジウム）、Ｓｉ（シリコン）、Ｓｎ（スズ）、Ｚｎ（亜鉛）、及びＡｌ（アルミニウム）からなる群から選択される少なくとも１種を含む。例えば、好ましいリチウムと合金化可能な金属は、Ａｕ（金）及びＩｎ（インジウム）から選択される少なくとも１種を含むものでありうる。リチウムと合金化可能な金属は、Ｍｇ２ＳｉやＭｇ２Ｓｎ等の２種類以上の元素により構成された合金であってもよい。酸化物系材料の例としては、Ｌｉ４Ｔｉ５Ｏ１２、ＴｉＯ２、ＳｉＯ等が挙げられる。中間層の形成は、エアロゾルデポジション（ＡＤ）法、パルスレーザー堆積（ＰＬＤ）法、スパッタリング法、蒸着法等の公知の方法により行えばよい。中間層の寸法は特に限定されないが、厚さは加熱時の合金化促進の観点から、厚さ０．０５～１μｍが好ましく、より好ましくは０．０５～０．５μｍ、さらに好ましくは０．０８～０．２μｍ、特に好ましくは０．１～０．１５μｍである。なお、ここで中間層として例示した材料はそれ自体で負極として充放電に寄与するため、これらの材料から選択される少なくとも１種の材料で負極を構成してもよい。 If desired, an intermediate layer may be interposed between the negative electrode layer 16 and the solid electrolyte layer 14. That is, the all-solid-state lithium battery 10 can further include an intermediate layer containing a metal that can be alloyed with lithium on the surface of the solid electrolyte layer 14 on the negative electrode layer 16 side. As a constituent material of the intermediate layer, a metal alloyed with lithium, an oxide-based material, or the like can be used. In this way, even when subjected to a process involving heating such as a reflow soldering process (for example, a process performed at a temperature of 200 ° C. or higher), the melting of lithium metal and the like is significantly suppressed, and therefore an internal short circuit And peeling of the negative electrode layer can be effectively prevented. Moreover, charge / discharge cycle characteristics can be improved. Metals that can be alloyed with lithium are Al (aluminum), Si (silicon), Zn (zinc), Ga (gallium), Ge (germanium), Ag (silver), Au (gold), Pt (platinum), Cd. It is preferable to include at least one selected from the group consisting of (cadmium), In (indium), Sn (tin), Sb (antimony), Pb (lead), and Bi (bismuth), and more preferably Au ( It contains at least one selected from the group consisting of gold), In (indium), Si (silicon), Sn (tin), Zn (zinc), and Al (aluminum). For example, a preferable metal alloyable with lithium may include at least one selected from Au (gold) and In (indium). The metal that can be alloyed with lithium may be an alloy composed of two or more elements such as Mg 2 Si and Mg 2 Sn. Examples of the oxide material include Li 4 Ti 5 O 12 , TiO 2 , and SiO. The intermediate layer may be formed by a known method such as an aerosol deposition (AD) method, a pulse laser deposition (PLD) method, a sputtering method, or an evaporation method. The dimension of the intermediate layer is not particularly limited, but the thickness is preferably 0.05 to 1 μm, more preferably 0.05 to 0.5 μm, and still more preferably 0.08, from the viewpoint of promoting alloying during heating. The thickness is from 0.2 to 0.2 μm, particularly preferably from 0.1 to 0.15 μm. In addition, since the material illustrated as an intermediate | middle layer here contributes to charging / discharging as a negative electrode in itself, you may comprise a negative electrode with at least 1 sort (s) of materials selected from these materials.
　端部絶縁部
　所望により、端部絶縁部１８が固体電解質層１４の端部を絶縁被覆するように設けられてもよい。端部絶縁部１８は、固体電解質層１４と接着又は密着可能な有機高分子材料を含むのが好ましい。端部絶縁部１８がそのような有機高分子材料を含むことで、配向正極板１２と負極層１６との短絡防止をより効果的に実現することができる。有機高分子材料は、バインダー、熱溶融樹脂及び接着剤からなる群から選択される少なくとも１種であるのが好ましい。バインダーの好ましい例としては、セルロース系樹脂、アクリル系樹脂、及びその組合せが挙げられる。熱融着樹脂の好ましい例としては、フッ素系樹脂、ポリオレフィン系樹脂、及びそれらの任意の組合せが挙げられる。熱溶融樹脂は後述するように熱融着フィルムの形態で供されるのが好ましい。接着剤の好ましい例としてはエポキシ系樹脂等の熱硬化性樹脂を用いた熱硬化型接着剤が挙げられる。したがって、有機高分子材料は、セルロース系樹脂、アクリル系樹脂、フッ素系樹脂、ポリオレフィン系樹脂及びエポキシ系樹脂からなる群から選択される少なくとも１種が好ましいといえる。セルロース系樹脂の例としては、カルボキシメチルセルロース、カルボキシエチルセルロース、ヒドロキシエチルセルロース、ヒドロキシプロピルセルロース、酪酸セルロース、酢酸酪酸セルロース、及び上記のアルカリ金属塩、及びアンモニウム塩が挙げられる。アクリル系樹脂の例としては、ポリアクリル酸エステル、ポリアクリル酸塩、並びにこれらの無水マレイン酸変性物、マレイン酸変性物及びフマル酸変性物が挙げられる。フッ素系樹脂の例としては、ポリフッ化ビニリデン（ＰＶｄＦ）、ポリテトラフルオロエチレン（ＰＴＦＥ）、テトラフルオロエチレン・パーフルオロアルキルビニルエーテル共重合体（ＰＦＡ）、テトラフルオロエチレン・ヘキサフルオロプロピレン共重合体（ＦＥＰ）、ポリクロロトリフルオロエチレン（ＰＣＴＦＥ）、テトラフルオロエチレン・ヘキサフルオロプロピレン・フッ化ビニリデン系共重合体、ヘキサフルオロプロピレン・フッ化ビニリデン系共重合体、並びにこれらの無水マレイン酸変性物、マレイン酸変性物及びフマル酸変性物が挙げられる。ポリオレフィン系樹脂の例としては、ポリエチレン、ポリプロピレン、シクロオレフィンポリマー、並びにこれらの無水マレイン酸変性物、マレイン酸変性物及びフマル酸変性物が挙げられる。 If desired, the end insulating portion 18 may be provided so as to insulate the end portion of the solid electrolyte layer 14. The end insulating portion 18 preferably includes an organic polymer material that can be adhered or adhered to the solid electrolyte layer 14. By including the organic polymer material in the end insulating portion 18, it is possible to more effectively realize prevention of short circuit between the oriented positive electrode plate 12 and the negative electrode layer 16. The organic polymer material is preferably at least one selected from the group consisting of a binder, a hot melt resin, and an adhesive. Preferable examples of the binder include a cellulose resin, an acrylic resin, and a combination thereof. Preferable examples of the heat fusion resin include a fluorine resin, a polyolefin resin, and any combination thereof. The hot-melt resin is preferably provided in the form of a heat-sealing film as will be described later. A preferable example of the adhesive is a thermosetting adhesive using a thermosetting resin such as an epoxy resin. Accordingly, it can be said that the organic polymer material is preferably at least one selected from the group consisting of a cellulose resin, an acrylic resin, a fluorine resin, a polyolefin resin, and an epoxy resin. Examples of the cellulose resin include carboxymethyl cellulose, carboxyethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, cellulose butyrate, cellulose acetate butyrate, and the alkali metal salts and ammonium salts described above. Examples of the acrylic resin include polyacrylic acid esters, polyacrylic acid salts, and maleic anhydride modified products, maleic acid modified products and fumaric acid modified products thereof. Examples of fluororesins include polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP). ), Polychlorotrifluoroethylene (PCTFE), tetrafluoroethylene / hexafluoropropylene / vinylidene fluoride copolymer, hexafluoropropylene / vinylidene fluoride copolymer, and maleic anhydride-modified products thereof, maleic acid Examples include modified products and fumaric acid modified products. Examples of the polyolefin-based resin include polyethylene, polypropylene, cycloolefin polymer, and maleic anhydride modified products, maleic acid modified products and fumaric acid modified products thereof.
　端部絶縁部１８の形成は、有機高分子材料（好ましくはバインダー）及び所望によりフィラー等を含む液体又はスラリーの塗布により行うのが好ましい。液体又はスラリーの塗布方法の好ましい例としては、ディスペンス法、スクリーン印刷法、スプレー法、スタンピング法等が挙げられる。 The end insulating portion 18 is preferably formed by applying a liquid or slurry containing an organic polymer material (preferably a binder) and optionally a filler or the like. Preferable examples of the liquid or slurry application method include a dispensing method, a screen printing method, a spray method, a stamping method, and the like.
　負極集電体
　負極層１６の外側には負極集電体２４が設けられるのが好ましい。負極集電体２４は負極の外側を被覆する負極外装材を兼ねていてもよい。例えば、図４に示されるように、図１に示される構成とは逆に、２個の単位電池を１枚の正極集電体２０を介して上下対称に並列積層して負極集電体２４を全固体リチウム電池の外側に露出させた構成としてもよい。このような並列積層型電池に構成される場合、正極集電体２０を隣り合う２個の単位電池に共通の集電体として機能させることができる。 The negative electrode current collector 24 is preferably provided outside the negative electrode current collector negative electrode layer 16. The negative electrode current collector 24 may also serve as a negative electrode exterior material that covers the outside of the negative electrode. For example, as shown in FIG. 4, contrary to the configuration shown in FIG. 1, two unit cells are stacked vertically and symmetrically via one positive current collector 20 to form a negative current collector 24. May be exposed to the outside of the all-solid-state lithium battery. When configured in such a parallel stacked battery, the positive electrode current collector 20 can function as a current collector common to two adjacent unit batteries.
　負極集電体２４は正極集電体２０と同種又は異種の材料で構成されてよいが、好ましくは同種の材料で構成される。負極集電体２４を構成する金属は、負極層１６と反応しないものであれば特に限定されず、合金であってもよい。そのような金属の好ましい例としては、ステンレス、アルミニウム、銅、白金、ニッケルが挙げられ、より好ましくはステンレスである。負極集電体２４は金属板又は金属箔であるのが好ましく、より好ましくは金属箔である。したがって、最も好ましい集電体はステンレス箔であるといえる。金属箔の好ましい厚さは１～３０μｍであり、より好ましくは５～２５μｍ、さらに好ましくは１０～２０μｍである。 The negative electrode current collector 24 may be made of the same or different material as the positive electrode current collector 20, but is preferably made of the same kind of material. The metal constituting the negative electrode current collector 24 is not particularly limited as long as it does not react with the negative electrode layer 16 and may be an alloy. Preferred examples of such metals include stainless steel, aluminum, copper, platinum, and nickel, and more preferably stainless steel. The negative electrode current collector 24 is preferably a metal plate or a metal foil, and more preferably a metal foil. Therefore, it can be said that the most preferred current collector is a stainless steel foil. The preferred thickness of the metal foil is 1 to 30 μm, more preferably 5 to 25 μm, and still more preferably 10 to 20 μm.
　端部封止部
　全固体リチウム電池１０には、正極集電体２０及び負極集電体２４で被覆されていない、配向正極板１２、固体電解質層１４、負極層１６及び（存在する場合には）端部絶縁部１８の露出部分を封止する、封着材で構成される端部封止部２６がさらに設けられるのが好ましい。端部封止部２６を設けて、正極集電体２０及び負極集電体２４で被覆されていない、配向正極板１２、固体電解質層１４、負極層１６及び端部絶縁部１８の露出部分を封止することで、優れた耐湿性（望ましくは高温における耐湿性）を確保することができる。それにより、全固体リチウム電池１０内への望ましくない水分の侵入を効果的に阻止して電池特性を向上できる。端部封止部２６は封着材で構成される。封着材は、正極集電体２０、負極集電体２４及び端部絶縁部１８で被覆されていない上記露出部分を封止して優れた耐湿性（望ましくは高温における耐湿性）を確保可能なものであれば特に限定されない。もっとも、封着材は正極集電体２０と負極集電体２４の間の電気的絶縁性を確保することが望まれるのはいうまでもない。その意味で、封着材は１×１０６Ωｃｍ以上の抵抗率を有するのが好ましく、より好ましくは１×１０７Ωｃｍ以上であり、さらに好ましくは１×１０８Ωｃｍ以上である。このような抵抗率であれば自己放電を有意に小さくすることができる。 The end-sealing portion all solid lithium battery 10 is not coated with the positive electrode current collector 20 and the negative electrode current collector 24, and is aligned with the positive electrode plate 12, the solid electrolyte layer 14, the negative electrode layer 16, and (if present) It is preferable that an end sealing portion 26 made of a sealing material for sealing the exposed portion of the end insulating portion 18 is further provided. An end sealing portion 26 is provided to expose exposed portions of the oriented positive electrode plate 12, the solid electrolyte layer 14, the negative electrode layer 16, and the end insulating portion 18 that are not covered with the positive electrode current collector 20 and the negative electrode current collector 24. By sealing, excellent moisture resistance (desirably moisture resistance at high temperature) can be ensured. Thereby, it is possible to effectively prevent undesirable moisture from entering the all solid lithium battery 10 and improve battery characteristics. The end sealing portion 26 is made of a sealing material. The sealing material can seal the exposed portion not covered with the positive electrode current collector 20, the negative electrode current collector 24, and the end insulating portion 18 to ensure excellent moisture resistance (preferably moisture resistance at high temperature). If it is a thing, it will not specifically limit. However, it goes without saying that it is desirable that the sealing material ensure electrical insulation between the positive electrode current collector 20 and the negative electrode current collector 24. In that sense, the sealing material preferably has a resistivity of 1 × 10 6 Ωcm or more, more preferably 1 × 10 7 Ωcm or more, and further preferably 1 × 10 8 Ωcm or more. Such a resistivity can significantly reduce self-discharge.
　端部封止部２６の厚さは好ましくは１０～３００μｍであり、より好ましくは１５～２００μｍ、さらに好ましくは２０～１５０μｍである。特に、金属製の正極集電体及び負極集電体で電池が被覆される構成の場合、電池内への水分の侵入は端部封止部２６を透過することによってのみ起こりうることになる。これは、正極集電体及び負極集電体が金属製であると水分を透過させないからである。そのため、端部封止部２６の厚さが薄い（すなわち水分侵入の入り口が狭い）程、また端部封止部の幅が大きい（すなわち水分侵入の経路が長い）程、電池内へ侵入する水分の量は少なくなる、すなわち耐湿性が向上する。そのような観点からも上記範囲内の厚さは好ましいといえる。 The thickness of the end sealing portion 26 is preferably 10 to 300 μm, more preferably 15 to 200 μm, still more preferably 20 to 150 μm. In particular, in the case where the battery is covered with a metal positive electrode current collector and a negative electrode current collector, the intrusion of moisture into the battery can only occur through the end sealing portion 26. This is because moisture is not transmitted when the positive electrode current collector and the negative electrode current collector are made of metal. Therefore, the thinner the end sealing portion 26 (that is, the narrower the entrance of moisture intrusion) is, and the greater the width of the end sealing portion (ie, the longer the path of moisture intrusion), the more the device enters the battery. The amount of moisture is reduced, that is, moisture resistance is improved. From such a viewpoint, it can be said that the thickness within the above range is preferable.
　端部封止部２６の幅（固体電解質層１４の層面方向の厚さともいえる）は好ましくは０．５～３ｍｍであり、より好ましくは０．７～２ｍｍであり、さらに好ましくは１～２ｍｍである。上記範囲内の幅であると、端部封止部２６が大きくなり過ぎることがないので、電池の体積エネルギー密度を高く確保することができる。 The width of the end sealing portion 26 (also referred to as the thickness of the solid electrolyte layer 14 in the layer surface direction) is preferably 0.5 to 3 mm, more preferably 0.7 to 2 mm, and further preferably 1 to 2 mm. It is. When the width is within the above range, the end sealing portion 26 does not become too large, so that the volume energy density of the battery can be secured high.
　封着材は、樹脂を含む樹脂系封着材であるのが好ましい。この場合、端部封止部２６の形成を比較的低温（例えば４００℃以下）で行うことができ、その結果、加熱を伴った封着に起因する電池の破壊や変質を効果的に防止することができる。樹脂は７×１０－６／℃以上の熱膨張係数を有するのが好ましく、より好ましくは９×１０－６～２０×１０－６／℃、さらに好ましくは１０×１０－６～１９×１０－６／℃、特に好ましくは１２×１０－６～１８×１０－６／℃、最も好ましくは１５×１０－６～１８×１０－６／℃である。また、樹脂は絶縁性樹脂であるのが好ましい。絶縁性樹脂は、絶縁性を保持しつつ接合することが可能な樹脂（熱や接着剤等で接着可能な接着性樹脂）であるのが好ましい。好ましい絶縁性樹脂の例としては、オレフィン系樹脂、フッ素系樹脂、アクリル系樹脂、エポキシ系樹脂、ウレタン系樹脂、及びシリコン系樹脂等が挙げられる。特に好ましい樹脂の例としては、低透湿樹脂封止材料として、ポリプロピレン（ＰＰ）、ポリエチレン（ＰＥ）、シクロオレフィンポリマー、及びポリクロロトリフルオロエチレン（ＰＣＴＦＥ）、並びにこれらの無水マレイン酸変性物、マレイン酸変性物及びフマル酸変性物に代表される熱融着型で水分透過率の低い接着性樹脂が挙げられる。絶縁性樹脂は、少なくとも１種又は複数種の積層体で構成されることができる。また、絶縁性樹脂の少なくとも１種として熱可塑性樹脂成形シートや、反応性の接着成分を有する樹脂を用いてもよい。樹脂系封着材は、樹脂（好ましくは絶縁性樹脂）と無機材料の混合物からなるものであってもよい。そのような無機材料の好ましい例としては、シリカ、アルミナ、酸化亜鉛、マグネシア、炭酸カルシウム、水酸化カルシウム、硫酸バリウム、マイカ、タルクが挙げられ、より好ましくはシリカである。例えば、エポキシ樹脂とシリカの混合物からなる樹脂系封着材が好ましく例示される。 The sealing material is preferably a resin-based sealing material containing a resin. In this case, the end sealing portion 26 can be formed at a relatively low temperature (for example, 400 ° C. or lower), and as a result, battery destruction and alteration due to sealing accompanied by heating can be effectively prevented. be able to. The resin preferably has a thermal expansion coefficient of 7 × 10 −6 / ° C. or more, more preferably 9 × 10 −6 to 20 × 10 −6 / ° C., and still more preferably 10 × 10 −6 to 19 × 10 −. 6 / ° C., particularly preferably 12 × 10 −6 to 18 × 10 −6 / ° C., most preferably 15 × 10 −6 to 18 × 10 −6 / ° C. The resin is preferably an insulating resin. The insulating resin is preferably a resin (adhesive resin that can be bonded with heat, an adhesive, or the like) that can be bonded while maintaining insulating properties. Examples of preferable insulating resins include olefin resins, fluorine resins, acrylic resins, epoxy resins, urethane resins, and silicon resins. Examples of particularly preferable resins include, as a low moisture-permeable resin sealing material, polypropylene (PP), polyethylene (PE), cycloolefin polymer, and polychlorotrifluoroethylene (PCTFE), and modified maleic anhydrides thereof, Examples thereof include an adhesive resin having a low water permeability and a heat fusion type typified by a maleic acid modified product and a fumaric acid modified product. The insulating resin can be composed of at least one or a plurality of types of laminates. Further, a thermoplastic resin molded sheet or a resin having a reactive adhesive component may be used as at least one kind of insulating resin. The resin-based sealing material may be made of a mixture of a resin (preferably an insulating resin) and an inorganic material. Preferable examples of such inorganic materials include silica, alumina, zinc oxide, magnesia, calcium carbonate, calcium hydroxide, barium sulfate, mica and talc, and silica is more preferable. For example, a resin-based sealing material made of a mixture of an epoxy resin and silica is preferably exemplified.
　端部封止部２６の形成は、正極集電体に対する樹脂フィルムの積層（熱融着もしくは接着剤を介しての貼り合せ）や、液状樹脂のディスペンス等により行えばよい。配向正極板１２、固体電解質層１４及び負極層１６の端部側面と、端部封止部２６との間に形成されうる隙間は端部絶縁部１８で十分に埋められるのが好ましい。 The end sealing portion 26 may be formed by laminating a resin film on the positive electrode current collector (thermal fusion or bonding via an adhesive), dispensing a liquid resin, or the like. It is preferable that gaps that can be formed between the end side surfaces of the alignment positive electrode plate 12, the solid electrolyte layer 14, and the negative electrode layer 16 and the end sealing portion 26 are sufficiently filled with the end insulating portion 18.
　あるいは、封着材は、ガラスを含むガラス系封着材であってもよい。ガラス系封着材は、Ｖ、Ｓｎ、Ｔｅ、Ｐ、Ｂｉ、Ｂ、Ｚｎ及びＰｂからなる群から選択される少なくとも１種を含むのが、望ましい軟化温度及び熱膨張係数を得やすい点で好ましい、これらの元素はＶ２Ｏ５、ＳｎＯ、ＴｅＯ２、Ｐ２Ｏ５、Ｂｉ２Ｏ３、Ｂ２Ｏ３、ＺｎＯ、及びＰｂＯの形でガラス中に存在しうるのはいうまでもない。もっとも、ガラス系封着材は有害物質となりうるＰｂないしＰｂＯを含まないのがより好ましい。ガラス系封着材は４００℃以下の軟化温度を有するのが好ましく、より好ましくは３７０℃以下、さらに好ましくは３５０℃以下である。軟化温度は、下限値に関して特に限定されないが、例えば３００℃以上、３１０℃以上又は３２０℃以上でありうる。いずれにしても、このように比較的低い軟化温度のガラス系封着材を用いることで、端部封止部２６の形成を比較的低温で行うことができ、その結果、加熱を伴った封着に起因する電池の破壊や変質を効果的に防止することができる。また、ガラス系封着材は７×１０－６／℃以上の熱膨張係数を有するのが好ましく、より好ましくは９×１０－６～２０×１０－６／℃、さらに好ましくは１０×１０－６～１９×１０－６／℃、特に好ましくは１２×１０－６～１８×１０－６／℃、最も好ましくは１５×１０－６～１８×１０－６／℃である。これらの範囲内の熱膨張係数は金属の熱膨張係数に近いため、金属製の集電体（すなわち正極集電体２０及び／又は負極集電体２４）と端部封止部２６の接合部における熱衝撃による破損を効果的に抑制することができる。上述した諸特性を満たすガラス系封着材は市販されている。例えば、ＡＧＣエレクトロニクス株式会社社から「ＰＯＷＤＥＲ　ＧＬＡＳＳ」（ＡＧＣガラスフリット）及び「ＧＬＡＳＳ　ＰＡＳＴＥ」（ＡＧＣガラスペースト）と称されて市販されている製品群、セントラル硝子株式会社から低融点ガラスペーストと称されて市販されているもの製品群、及び日立化成株式会社から「バニーテクト」と称されて市販されているバナジウム系低融点ガラスの製品群に上述した諸特性を満たすガラス系封着材を見つけることができる。 Alternatively, the sealing material may be a glass-based sealing material containing glass. It is preferable that the glass-based sealing material contains at least one selected from the group consisting of V, Sn, Te, P, Bi, B, Zn, and Pb from the viewpoint of easily obtaining a desired softening temperature and thermal expansion coefficient. Of course, these elements may be present in the glass in the form of V 2 O 5 , SnO, TeO 2 , P 2 O 5 , Bi 2 O 3 , B 2 O 3 , ZnO, and PbO. However, it is more preferable that the glass-based sealing material does not contain Pb or PbO which can be a harmful substance. The glass-based sealing material preferably has a softening temperature of 400 ° C. or lower, more preferably 370 ° C. or lower, and further preferably 350 ° C. or lower. The softening temperature is not particularly limited with respect to the lower limit value, but may be, for example, 300 ° C or higher, 310 ° C or higher, or 320 ° C or higher. In any case, by using the glass-based sealing material having a relatively low softening temperature in this manner, the end sealing portion 26 can be formed at a relatively low temperature, and as a result, sealing with heating is performed. It is possible to effectively prevent the destruction and alteration of the battery due to the wearing. The glass-based sealing material preferably has a thermal expansion coefficient of 7 × 10 −6 / ° C. or more, more preferably 9 × 10 −6 to 20 × 10 −6 / ° C., and still more preferably 10 × 10 −. 6 to 19 × 10 −6 / ° C., particularly preferably 12 × 10 −6 to 18 × 10 −6 / ° C., and most preferably 15 × 10 −6 to 18 × 10 −6 / ° C. Since the thermal expansion coefficient within these ranges is close to the thermal expansion coefficient of the metal, the junction between the metal current collector (that is, the positive electrode current collector 20 and / or the negative electrode current collector 24) and the end sealing portion 26. Breakage due to thermal shock in can be effectively suppressed. Glass-based sealing materials that satisfy the various characteristics described above are commercially available. For example, a product group called “POWDER GLASS” (AGC glass frit) and “GLASS PATHE” (AGC glass paste) marketed by AGC Electronics Co., Ltd., and a low melting point glass paste from Central Glass Co., Ltd. To find glass-based sealing materials that satisfy the above-mentioned characteristics in the product group that is commercially available and the product group of vanadium-based low-melting-point glass that is called “Bunny Tect” from Hitachi Chemical Co., Ltd. it can.
　電池厚さ
　全固体リチウム電池は、単位電池１個を備えた構成の場合、６０～５０００μｍの厚さを有するのが好ましく、より好ましくは、７０～４０００μｍ、さらに好ましくは、８０～３０００μｍ、特に好ましくは、９０～２０００μｍ、最も好ましくは、１００～１０００μｍである。本発明によれば、配向正極板を比較的厚くできる一方、集電体で外装材を兼用するため電池全体の厚さを比較的薄く構成することができる。 Battery thickness In the case of a configuration including one unit battery, the all-solid lithium battery preferably has a thickness of 60 to 5000 μm, more preferably 70 to 4000 μm, still more preferably 80 to 3000 μm, and particularly preferably. Is from 90 to 2000 μm, most preferably from 100 to 1000 μm. According to the present invention, the oriented positive electrode plate can be made relatively thick, while the current collector also serves as an exterior material, so that the thickness of the entire battery can be made relatively thin.
　コバルト酸リチウム配向焼結板の製造方法
　本発明の全固体リチウム電池に用いられる配向正極板ないし配向焼結板は、いかなる製法によって製造されてもよいが、好ましくは、以下に例示されるように、（１）ＬｉＣｏＯ２テンプレート粒子の作製、（２）マトリックス粒子の作製、（３）グリーンシートの作製、及び（４）配向焼結板の作製を経て製造される。 Method for Producing Lithium Cobalt Oxide Oriented Sintered Plate The oriented positive electrode plate or oriented sintered plate used in the all solid lithium battery of the present invention may be produced by any method, but preferably, as exemplified below (1) Production of LiCoO 2 template particles, (2) Production of matrix particles, (3) Production of green sheets, and (4) Production of oriented sintered plates.
（１）ＬｉＣｏＯ２テンプレート粒子の作製
　Ｃｏ３Ｏ４原料粉末とＬｉ２ＣＯ３原料粉末とを混合して焼成（５００～９００℃、１～２０時間）することによって、ＬｉＣｏＯ２粉末を合成する。得られたＬｉＣｏＯ２粉末をポットミルにて体積基準Ｄ５０粒径０．２μｍ～１０μｍに粉砕することによって、板面と平行にリチウムイオンを伝導可能な板状のＬｉＣｏＯ２粒子が得られる。このようなＬｉＣｏＯ２粒子は、ＬｉＣｏＯ２粉末スラリーを用いたグリーンシートを粒成長させた後に解砕する手法や、フラックス法や水熱合成、融液を用いた単結晶育成、ゾルゲル法など板状結晶を合成する手法によっても得ることができる。得られたＬｉＣｏＯ２粒子は、劈開面に沿って劈開しやすい状態となっている。ＬｉＣｏＯ２粒子を解砕によって劈開させることで、ＬｉＣｏＯ２テンプレート粒子を作製する。 (1) Preparation of LiCoO 2 Template Particles Co 3 O 4 raw material powder and Li 2 CO 3 raw material powder are mixed and fired (500 to 900 ° C., 1 to 20 hours) to synthesize LiCoO 2 powder. The obtained LiCoO 2 powder is pulverized to a volume-based D50 particle size of 0.2 μm to 10 μm by a pot mill to obtain plate-like LiCoO 2 particles capable of conducting lithium ions in parallel with the plate surface. Such LiCoO 2 particles can be obtained by a method of crushing after growing a green sheet using LiCoO 2 powder slurry, a plate method such as a flux method, hydrothermal synthesis, single crystal growth using a melt, or a sol-gel method. It can also be obtained by a method of synthesizing crystals. The obtained LiCoO 2 particles are easily cleaved along the cleavage plane. It is to cleave by crushing the LiCoO 2 particles to prepare a LiCoO 2 template particles.
（２）マトリックス粒子の作製
　Ｃｏ３Ｏ４原料粉末をマトリックス粒子として用いる。Ｃｏ３Ｏ４原料粉末の体積基準Ｄ５０粒径は特に制限されず、例えば０．１～１．０μｍとすることができるが、ＬｉＣｏＯ２テンプレート粒子の体積基準Ｄ５０粒径より小さいことが好ましい。このマトリックス粒子は、Ｃｏ（ＯＨ）２原料を５００℃～８００℃で１～１０時間熱処理を行なうことによっても得ることができる。また、マトリックス粒子には、Ｃｏ３Ｏ４のほか、Ｃｏ（ＯＨ）２粒子を用いてもよいし、ＬｉＣｏＯ２粒子を用いてもよい。 (2) Production of matrix particles Co 3 O 4 raw material powder is used as matrix particles. The volume-based D50 particle size of the Co 3 O 4 raw material powder is not particularly limited and can be, for example, 0.1 to 1.0 μm, but is preferably smaller than the volume-based D50 particle size of LiCoO 2 template particles. The matrix particles can also be obtained by subjecting a Co (OH) 2 raw material to heat treatment at 500 ° C. to 800 ° C. for 1 to 10 hours. In addition to Co 3 O 4 , Co (OH) 2 particles or LiCoO 2 particles may be used as matrix particles.
（３）グリーンシートの作製
　ＬｉＣｏＯ２テンプレート粒子とマトリックス粒子を１００：３～３：９７に混合した粉末と分散媒とバインダーと可塑剤と分散剤とを混合しながら、減圧下で撹拌して脱泡するとともに所望の粘度に調整することによってスラリーを調製する。次に、ＬｉＣｏＯ２テンプレート粒子にせん断力を印加可能な成形手法を用いて、調製したスラリーを成形することによって、成形体を形成する。これによって、各一次粒子の平均配向角度を０°超３０°以下とすることができる。ＬｉＣｏＯ２テンプレート粒子にせん断力を印加可能な成形手法としては、ドクターブレード法が好適である。ドクターブレード法を用いる場合には、調製したスラリーをＰＥＴフィルムの上に成形することによって、成形体としてのグリーンシートが形成される。 (3) Preparation of green sheet While mixing powder, dispersion medium, binder, plasticizer and dispersant in which LiCoO 2 template particles and matrix particles are mixed in a ratio of 100: 3 to 3:97, the mixture is stirred and removed under reduced pressure. A slurry is prepared by foaming and adjusting to the desired viscosity. Next, a molded body is formed by molding the prepared slurry using a molding technique capable of applying a shearing force to LiCoO 2 template particles. Thereby, the average orientation angle of each primary particle can be made to be more than 0 ° and not more than 30 °. A doctor blade method is suitable as a forming technique capable of applying a shearing force to LiCoO 2 template particles. When the doctor blade method is used, a green sheet as a molded body is formed by molding the prepared slurry on a PET film.
（４）配向焼結板の作製
　スラリーの成形体をジルコニア製セッターに載置して加熱処理（５００℃～９００℃、１～１０時間）することによって、中間体としての焼結板を得る。次に、合成したリチウムシートをＬｉ／Ｃｏ比が１．０になるように、焼結板をリチウムシートで上下挟み込み、ジルコニアセッター上に載せる。次に、セッターをアルミナ鞘に入れ、大気中にて焼成（７００～８５０℃、１～２０時間）した後、焼結板をリチウムシートで上下挟み、さらに焼成（７５０～９００℃、１～４０時間）することによって、ＬｉＣｏＯ２焼結板を得る。この焼成工程は、２度に分けて行ってもよいし、１度に行なってもよい。２度に分けて焼成する場合には、１度目の焼成温度が２度目の焼成温度より低いことが好ましい。 (4) Production of Oriented Sintered Plate The slurry compact is placed on a zirconia setter and subjected to heat treatment (500 ° C. to 900 ° C., 1 to 10 hours) to obtain a sintered plate as an intermediate. Next, the sintered plate is sandwiched between lithium sheets so that the Li / Co ratio is 1.0, and the synthesized lithium sheet is placed on a zirconia setter. Next, the setter is put into an alumina sheath and fired in the atmosphere (700 to 850 ° C., 1 to 20 hours), and then the sintered plate is sandwiched between lithium sheets and further fired (750 to 900 ° C., 1 to 40 Time) to obtain a LiCoO 2 sintered plate. This firing step may be performed in two steps or may be performed once. When firing twice, it is preferable that the first firing temperature is lower than the second firing temperature.
　本発明を以下の例によってさらに具体的に説明する。 The present invention will be described more specifically with reference to the following examples.
　例Ａ１～Ａ８
（１）ＬＣＯテンプレート粒子の作製
　Ｃｏ３Ｏ４原料粉末（体積基準Ｄ５０粒径０．８μｍ、正同化学工業株式会社製）とＬｉ２ＣＯ３原料粉末（体積基準Ｄ５０粒径２．５μｍ、本荘ケミカル製）を混合し、８００℃～９００℃で５時間焼成することでＬｉＣｏＯ２原料粉末を合成した。この際、熱処理温度とＬｉ／Ｃｏ比を調整することによって、ＬｉＣｏＯ２原料粉末の体積基準Ｄ５０粒径を表１に示すように調整した。 Examples A1 to A8
(1) Preparation of LCO template particles Co 3 O 4 raw material powder (volume basis D50 particle size 0.8 μm, manufactured by Shodo Chemical Co., Ltd.) and Li 2 CO 3 raw material powder (volume basis D50 particle size 2.5 μm, Honjo) Chemical) was mixed and baked at 800 ° C. to 900 ° C. for 5 hours to synthesize LiCoO 2 raw material powder. At this time, the volume-based D50 particle size of the LiCoO 2 raw material powder was adjusted as shown in Table 1 by adjusting the heat treatment temperature and the Li / Co ratio.
　得られたＬｉＣｏＯ２粉末を粉砕することによって板状ＬｉＣｏＯ２粒子（ＬＣＯテンプレート粒子）を得た。例Ａ１～Ａ２，Ａ４～Ａ８ではポットミルを用い、例Ａ３では湿式ジェットミルを用いた。この際、粉砕時間を調整することによって、ＬＣＯテンプレート粒子の体積基準Ｄ５０粒径を表１に示すように調整した。また、ＬｉＣｏＯ２テンプレート粒子のアスペクト比は、表１に示すとおりであった。ＬｉＣｏＯ２テンプレート粒子のアスペクト比は、粒子をＳＥＭ観察することで測定した。 The obtained LiCoO 2 powder was pulverized to obtain plate-like LiCoO 2 particles (LCO template particles). In Examples A1 to A2 and A4 to A8, a pot mill was used, and in Example A3, a wet jet mill was used. At this time, the volume-based D50 particle size of the LCO template particles was adjusted as shown in Table 1 by adjusting the grinding time. The aspect ratio of LiCoO 2 template particles were as shown in Table 1. The aspect ratio of LiCoO 2 template particles was measured by observing the particles with SEM.
（２）ＣｏＯマトリックス粒子の作製
　Ｃｏ３Ｏ４原料粉末（正同化学工業株式会社製）をマトリックス粒子とした。マトリックス粒子の体積基準Ｄ５０粒径は、表１に示すとおりとした。ただし、例Ａ４ではマトリックス粒子を用いなかった。 (2) Preparation of CoO matrix particles Co 3 O 4 raw material powder (manufactured by Shodo Chemical Industry Co., Ltd.) was used as matrix particles. The volume-based D50 particle size of the matrix particles was as shown in Table 1. However, Example A4 did not use matrix particles.
（３）グリーンシートの作製
　ＬＣＯテンプレート粒子とＣｏＯマトリックス粒子を混合した。ＬＣＯテンプレート粒子とＣｏＯマトリックス粒子の重量比は、表１に示すとおりとした。ただし、例Ａ４ではマトリックス粒子を用いなかったため、重量比は、１００：０である。 (3) Production of green sheet LCO template particles and CoO matrix particles were mixed. The weight ratio between the LCO template particles and the CoO matrix particles was as shown in Table 1. However, in Example A4, since no matrix particles were used, the weight ratio was 100: 0.
　この混合粉末１００重量部と、分散媒（トルエン：イソプロパノール＝１：１）１００重量部と、バインダー（ポリビニルブチラール：品番ＢＭ－２、積水化学工業株式会社製）１０重量部と、可塑剤（ＤＯＰ：Ｄｉ（２－ｅｔｈｙｌｈｅｘｙｌ）ｐｈｔｈａｌａｔｅ、黒金化成株式会社製）４重量部と、分散剤（製品名レオドールＳＰ－Ｏ３０、花王株式会社製）２重量部とを混合した。この混合物を、減圧下で撹拌することで脱泡するとともに粘度を４０００１００００ｃＰに調整することによってスラリーを調製した。なお、粘度は、ブルックフィールド社製ＬＶＴ型粘度計で測定した。 100 parts by weight of the mixed powder, 100 parts by weight of a dispersion medium (toluene: isopropanol = 1: 1), 10 parts by weight of a binder (polyvinyl butyral: product number BM-2, manufactured by Sekisui Chemical Co., Ltd.), and a plasticizer (DOP : 4 parts by weight of Di (2-ethylhexyl) phthalate (manufactured by Kurokin Kasei Co., Ltd.) and 2 parts by weight of a dispersant (product name: Leodol SP-O30, manufactured by Kao Corporation) were mixed. The mixture was degassed by stirring under reduced pressure, and a slurry was prepared by adjusting the viscosity to 40960000 cP. The viscosity was measured with an LVT viscometer manufactured by Brookfield.
　調製されたスラリーを、ドクターブレード法によって、ＰＥＴフィルムの上に、乾燥後の厚さが４０μｍとなるように、成形速度１００ｍ／ｈでシート状に成形してグリーンシートを得た。 The prepared slurry was formed into a sheet on a PET film by a doctor blade method so that the thickness after drying was 40 μm at a forming speed of 100 m / h to obtain a green sheet.
（４）配向焼結板の作製
　ＰＥＴフィルムから剥がしたグリーンシートをジルコニア製セッターに載置して一次焼成することによってＣｏ３Ｏ４焼結板を得た。表１に示すとおり、例Ａ１～Ａ６，Ａ８では焼成条件を９００℃、５時間とし、例Ａ７では焼成条件を８００℃、５時間とした。 (4) Production of Oriented Sintered Plate A green sheet peeled from the PET film was placed on a zirconia setter and subjected to primary firing to obtain a Co 3 O 4 sintered plate. As shown in Table 1, in Examples A1 to A6 and A8, the firing conditions were 900 ° C. and 5 hours, and in Example A7, the firing conditions were 800 ° C. and 5 hours.
　そして、合成したリチウムシートをＬｉ／Ｃｏ比が表１に示す比になるように、Ｃｏ３Ｏ４焼結板をリチウムシートで上下挟み込んだ状態で、ジルコニアセッター上に載せて二次焼成することによってＬｉＣｏＯ２焼結板を得た。具体的には、ジルコニアセッターを９０ｍｍ角のアルミナ鞘に入れ、大気中にて８００℃で５時間保持した後、さらにリチウムシートで上下挟んで９００℃で２０時間焼成した。 Then, the synthesized lithium sheet is subjected to secondary firing by placing it on a zirconia setter with the Co 3 O 4 sintered plate sandwiched between the lithium sheets so that the Li / Co ratio is as shown in Table 1. To obtain a LiCoO 2 sintered plate. Specifically, the zirconia setter was placed in a 90 mm square alumina sheath, held in the atmosphere at 800 ° C. for 5 hours, and then further sandwiched between lithium sheets and fired at 900 ° C. for 20 hours.
（５）固体電解質層の作製
　直径４インチ（約１０ｃｍ）のリン酸リチウム焼結体ターゲットを準備し、スパッタリング装置（キャノンアネルバ社製　ＳＰＦ－４３０Ｈ）を用いてＲＦマグネトロン方式にてガス種Ｎ２を０．２Ｐａ、出力０．２ｋＷにて膜厚２μｍとなるようにスパッタリングを行なった。こうして、厚さ２μｍのＬｉＰＯＮ系固体電解質スパッタ膜をＬｉＣｏＯ２焼結板上に形成した。 (5) Preparation of solid electrolyte layer A lithium phosphate sintered compact target having a diameter of 4 inches (about 10 cm) was prepared, and a gas type N 2 was obtained by a RF magnetron method using a sputtering apparatus (SPF-430H manufactured by Canon Anelva). Was sputtered to a thickness of 2 μm at 0.2 Pa and an output of 0.2 kW. Thus, a LiPON solid electrolyte sputtered film having a thickness of 2 μm was formed on the LiCoO 2 sintered plate.
（６）リチウムイオン電池の作製
　イオンスパッタリング装置（日本電子社製　ＪＦＣ－１５００）を用いたスパッタリングにより、固体電解質層上に厚さ５００ÅのＡｕ膜を形成した。 (6) Production of Lithium Ion Battery An Au film having a thickness of 500 mm was formed on the solid electrolyte layer by sputtering using an ion sputtering apparatus (JFC-1500 manufactured by JEOL Ltd.).
　リチウム金属を載せたタングステンボートを準備した。真空蒸着装置（サンユー電子製、カーボンコーターＳＶＣ－７００）を用いて、抵抗加熱によりＬｉを蒸発させて上記中間層の表面に薄膜を設ける蒸着を行った。このとき、マスクを用いて負極層のサイズを９．５ｍｍ角として、負極層が１０ｍｍ角の正極領域内に収まるようにした。こうして、固体電解質層上に膜厚１０μｍのＬｉ蒸着膜を負極層として形成した単電池を作製した。 タ ン グ ス テ ン A tungsten boat with lithium metal was prepared. Using a vacuum deposition apparatus (carbon coater SVC-700, manufactured by Sanyu Denshi), vapor deposition was performed in which Li was evaporated by resistance heating to form a thin film on the surface of the intermediate layer. At this time, using a mask, the size of the negative electrode layer was set to 9.5 mm square so that the negative electrode layer was within the 10 mm square positive electrode region. In this way, a unit cell was produced in which a Li-deposited film having a thickness of 10 μm was formed as a negative electrode layer on the solid electrolyte layer.
　厚さ２０μｍのステンレス箔を１３ｍｍ角に切り出して正極集電板とした。また、外縁形状が１３ｍｍ角で、その内側に１１ｍｍ角の孔が打ち抜かれた、１ｍｍ幅の枠状の変性ポリプロピレン樹脂フィルム（厚さ１００μｍ）を用意した。この枠状の樹脂フィルムを正極集電板上の外周部に積層し、加熱圧着して端部封止部を形成した。正極集電板上の端部封止部で囲まれた領域内に上記単電池を載置した。載置した単電池の負極側にも上記同様に厚さ２０μｍのステンレス箔を載置し、端部封止部に対して荷重を加えながら、減圧下、２００℃で加熱した。こうして外周全体にわたって端部封止部と上下２枚のステンレス箔とを貼り合せて単電池を封止した。こうして、封止形態の全固体リチウム電池を得た。 A 20 μm thick stainless steel foil was cut into a 13 mm square to form a positive electrode current collector. Also, a 1 mm wide frame-shaped modified polypropylene resin film (thickness: 100 μm) having an outer edge shape of 13 mm square and an 11 mm square hole punched inside thereof was prepared. This frame-shaped resin film was laminated on the outer peripheral portion on the positive electrode current collector plate, and heat-pressed to form an end sealing portion. The unit cell was placed in a region surrounded by the end sealing portion on the positive electrode current collector plate. Similarly to the above, a stainless steel foil having a thickness of 20 μm was placed on the negative electrode side of the placed unit cell, and heated at 200 ° C. under reduced pressure while applying a load to the end sealing portion. Thus, the end sealing part and the upper and lower two stainless steel foils were bonded together over the entire outer periphery to seal the unit cell. Thus, an all solid lithium battery in a sealed form was obtained.
（正極を構成する一次粒子の観察）
　後方散乱電子回折像システム付の走査型電子顕微鏡（日立ハイテクノロジーズ製ＦＥ－ＳＥＭ、ＳＵ５０００及びオックスフォード・インストゥルメンツ製ＥＢＳＤ検出器、ＮｏｒｄｌｙＮａｎｏ）を用いて、正極の板面に垂直な断面におけるＥＢＳＤ像を取得した。そして、ＥＢＳＤ像上において、前述の条件で選択した３０個程度の一次粒子の配向角度を算術平均することによって、一次粒子の平均配向角度を算出した。算出結果は表２に示すとおりであった。いずれの例においても、板面と（００３）面がなす角度が３０度以内、より典型的には２５度以内、さらに典型的には２０度以内、特に典型的には１５度以内、特に典型的には１０度以内、最も典型的には５度以内である複数の結晶粒（一次粒子）を含んでおり、（００３）面が配向正極板の板面に対して平行に配向している複数の結晶粒が含まれていることが確認された。 (Observation of primary particles constituting the positive electrode)
Using a scanning electron microscope with a backscattered electron diffraction image system (FE-SEM, SU5000 manufactured by Hitachi High-Technologies, EBSD detector manufactured by Oxford Instruments, Nordly Nano), an EBSD image in a cross section perpendicular to the plate surface of the positive electrode Acquired. Then, on the EBSD image, the average orientation angle of the primary particles was calculated by arithmetically averaging the orientation angles of about 30 primary particles selected under the above conditions. The calculation results were as shown in Table 2. In any example, the angle formed between the plate surface and the (003) plane is within 30 degrees, more typically within 25 degrees, more typically within 20 degrees, particularly typically within 15 degrees, particularly typical. In particular, it includes a plurality of crystal grains (primary particles) within 10 degrees, most typically within 5 degrees, and the (003) plane is oriented parallel to the plate surface of the oriented positive electrode plate. It was confirmed that a plurality of crystal grains were included.
　また、ＥＢＳＤ像において、平均配向角度の算出に用いた３０個程度の一次粒子の総面積に対する、配向角度が０°超３０°以下である一次粒子の合計面積の割合（％）を算出した。算出結果は表２に示すとおりであった。 Further, in the EBSD image, the ratio (%) of the total area of primary particles having an orientation angle of more than 0 ° and 30 ° or less to the total area of about 30 primary particles used for calculating the average orientation angle was calculated. The calculation results were as shown in Table 2.
（正極の緻密度）
　ＣＰ研磨した正極の断面における１０００倍率のＳＥＭ画像を２値化した。そして、２値化画像上において、固相と気相の合計面積に対する固相の面積割合を緻密度として算出した。算出結果は表２に示すとおりであった。 (Positive electrode density)
A 1000-magnification SEM image in the cross section of the CP-polished positive electrode was binarized. Then, on the binarized image, the area ratio of the solid phase to the total area of the solid phase and the gas phase was calculated as the density. The calculation results were as shown in Table 2.
（レート性能）
　リチウムイオン電池を０．１［ｍＡ］定電流で４．２［Ｖ］まで充電した後、定電圧で電流が０．０５［ｍＡ］になるまで充電した。そして、０．２［ｍＡ］定電流で３．０［Ｖ］まで放電し、放電容量Ｗ０を測定した。また０．１［ｍＡ］定電流で４．２［Ｖ］まで充電した後、定電圧で電流が０．０５［ｍＡ］になるまで充電し、そして、２．０［ｍＡ］定電流で３．０［Ｖ］まで放電し、放電容量Ｗ１を測定した。Ｗ１をＷ０で除することでレート性能を評価した。 (Rate performance)
The lithium ion battery was charged to 4.2 [V] at a constant current of 0.1 [mA], and then charged to 0.05 [mA] at a constant voltage. And it discharged to 3.0 [V] with a 0.2 [mA] constant current, and measured the discharge capacity W0. Moreover, after charging to 4.2 [V] at a constant current of 0.1 [mA], charging is performed until the current reaches 0.05 [mA] at a constant voltage, and then 3 at a constant current of 2.0 [mA]. The battery was discharged to 0.0 [V], and the discharge capacity W1 was measured. The rate performance was evaluated by dividing W1 by W0.
（サイクル容量維持率）
　リチウムイオン電池を０．１［ｍＡ］定電流で４．２［Ｖ］まで充電した後、定電圧で電流が０．０５［ｍＡ］になるまで充電した。そして、０．２［ｍＡ］定電流で３．０［Ｖ］まで放電し、放電容量Ｗ０を測定した。この測定を３０回繰り返し、３０回目の放電容量Ｗ３０を測定した。Ｗ３０をＷ０で除することでサイクル容量維持率を評価した。
  (Cycle capacity maintenance rate)
The lithium ion battery was charged to 4.2 [V] at a constant current of 0.1 [mA], and then charged to 0.05 [mA] at a constant voltage. And it discharged to 3.0 [V] with a 0.2 [mA] constant current, and measured the discharge capacity W0. This measurement was repeated 30 times, and the 30th discharge capacity W30 was measured. The cycle capacity retention rate was evaluated by dividing W30 by W0.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表２に示すように、板状のＬＣＯテンプレート粒子にせん断力を印加する成形手法で正極の成形体を形成した例Ａ１～Ａ８では、一次粒子の（００３）面の傾斜角度を２５°以下にすることができたため、サイクル容量維持率だけでなくレート性能をも向上させることができた。 As shown in Table 2, in Examples A1 to A8 in which the molded body of the positive electrode was formed by a molding technique in which a shearing force was applied to the plate-like LCO template particles, the inclination angle of the (003) plane of the primary particles was 25 ° or less. As a result, not only the cycle capacity maintenance rate but also the rate performance could be improved.
　例Ｂ１（比較）
　本例は、（１０４）面が板面に対して平行に配向した（すなわち（００３）面が板面と平行に配向していない）配向正極板が集電板へ接着された状態の全固体リチウム電池を作製及び評価した比較例である。 Example B1 (comparison)
In this example, the (104) plane is aligned in parallel to the plate surface (that is, the (003) plane is not aligned in parallel to the plate surface), and an all-solid-state in which the aligned positive plate is bonded to the current collector plate. It is the comparative example which produced and evaluated the lithium battery.
（１）配向正極板の作製
（１ａ）グリーンシートの作製
　Ｃｏ３Ｏ４原料粉末（体積基準Ｄ５０粒径０．３μｍ、正同化学工業株式会社製）に５ｗｔ％の割合でＢｉ２Ｏ３（体積基準Ｄ５０粒径０．３μｍ、太陽鉱工株式会社製）を添加して混合粉末を得た。この混合粉末１００重量部と、分散媒（トルエン：イソプロパノール＝１：１）１００重量部と、バインダー（ポリビニルブチラール：品番ＢＭ－２、積水化学工業株式会社製）１０重量部と、可塑剤（ＤＯＰ：ジ（２－エチルヘキシル）フタレート、黒金化成株式会社製）４重量部と、分散剤（製品名レオドールＳＰ－Ｏ３０、花王株式会社製）２重量部とを混合した。この混合物を、減圧下で撹拌することで脱泡するとともに、４０００ｃＰの粘度に調整した。なお、粘度は、ブルックフィールド社製ＬＶＴ型粘度計で測定した。上記のようにして調製されたスラリーを、ドクターブレード法によって、ＰＥＴ（ポリエチレンテレフタレート）フィルムの上に、乾燥後の厚さが４０μｍとなるように、シート状に成形してグリーンシートを得た。 (1) Preparation of oriented positive electrode plate (1a) Preparation of green sheet Bi 2 O 3 (Co 2 O 3 raw material powder (volume basis D50 particle size 0.3 μm, manufactured by Shodo Chemical Industry Co., Ltd.)) Volume standard D50 particle size 0.3 μm, manufactured by Taiyo Mining Co., Ltd.) was added to obtain a mixed powder. 100 parts by weight of the mixed powder, 100 parts by weight of a dispersion medium (toluene: isopropanol = 1: 1), 10 parts by weight of a binder (polyvinyl butyral: product number BM-2, manufactured by Sekisui Chemical Co., Ltd.), and a plasticizer (DOP : 4 parts by weight of di (2-ethylhexyl) phthalate (manufactured by Kurokin Kasei Co., Ltd.) and 2 parts by weight of a dispersant (product name: Leodol SP-O30, Kao Corporation) were mixed. The mixture was defoamed by stirring under reduced pressure and adjusted to a viscosity of 4000 cP. The viscosity was measured with an LVT viscometer manufactured by Brookfield. The slurry prepared as described above was formed into a sheet shape on a PET (polyethylene terephthalate) film so that the thickness after drying was 40 μm by a doctor blade method to obtain a green sheet.
（１ｂ）配向焼結板の作製
　ＰＥＴフィルムから剥がしたグリーンシートを、カッターで４０ｍｍ角に切り出し、突起の高さが３００μｍのエンボス加工を施したジルコニア製セッター（寸法９０ｍｍ角、高さ１ｍｍ）の中央に載置し、１３００℃で５時間焼成後、降温速度５０℃／ｈにて降温し、セッターに溶着していない部分をＣｏ３Ｏ４配向焼結板として取り出した。 (1b) Preparation of oriented sintered plate A green sheet peeled off from a PET film was cut into a 40 mm square with a cutter, and a zirconia setter (dimension 90 mm square, height 1 mm) embossed with a projection height of 300 μm After placing at the center and firing at 1300 ° C. for 5 hours, the temperature was decreased at a temperature decrease rate of 50 ° C./h, and the portion not welded to the setter was taken out as a Co 3 O 4 oriented sintered plate.
（１ｃ）リチウムの導入
　ＬｉＯＨ・Ｈ２Ｏ粉末（和光純薬工業株式会社製）をジェットミルで１μｍ以下に粉砕し、エタノールに分散したスラリーを作製した。このスラリーを上記Ｃｏ３Ｏ４配向焼結板にＬｉ／Ｃｏ＝１．３になるように塗布し、乾燥した。その後、ジルコニアセッター上に載せ、大気中にて８４０℃で２０時間加熱処理して厚さ４５μｍからなるＬｉＣｏＯ２配向焼結板を配向正極板として得た。得られた焼結板の嵩密度をアルキメデス法で測定し、嵩密度をコバルト酸リチウムの真密度５．０５ｇ/ｃｍ３で除することにより、緻密度を算出した。その結果、焼結板の緻密度は９７％であった。 (1c) Introduction of Lithium LiOH · H 2 O powder (manufactured by Wako Pure Chemical Industries, Ltd.) was pulverized to 1 μm or less with a jet mill to prepare a slurry dispersed in ethanol. This slurry was applied to the Co 3 O 4 oriented sintered plate so that Li / Co = 1.3, and dried. After that, it was placed on a zirconia setter and heat-treated at 840 ° C. for 20 hours in the air to obtain a LiCoO 2 oriented sintered plate having a thickness of 45 μm as an oriented positive plate. The bulk density of the obtained sintered plate was measured by Archimedes method, and the density was calculated by dividing the bulk density by the true density of lithium cobaltate of 5.05 g / cm 3 . As a result, the density of the sintered plate was 97%.
（２）全固体リチウム電池の作製
（２ａ）導電膜の作製
　イオンスパッタリング装置（日本電子製、ＪＦＣ－１５００）を用いたスパッタリングにより、コバルト酸リチウム配向正極板の片面に厚さ１０００ÅのＡｕ膜を導電膜として形成した。 (2) Production of all solid lithium battery (2a) Production of conductive film By sputtering using an ion sputtering apparatus (JFC-1500, manufactured by JEOL Ltd.), an Au film having a thickness of 1000 mm was formed on one surface of a lithium cobaltate oriented positive electrode plate. It formed as an electrically conductive film.
（２ｂ）配向正極板の固定
　上記コバルト酸リチウム配向焼結板を１０ｍｍ角に切出し、配向焼結板の導電膜面を、導電性カーボンを分散させたエポキシ樹脂系の導電性接着剤で、ステンレス集電板（正極外装材、１３ｍｍ角、厚さ１００μｍ）上に固定することによって、平板状の配向正極板／導電性接着剤／正極外装材の積層板を得た。 (2b) Fixing the Oriented Positive Electrode Plate The lithium cobaltate oriented sintered plate is cut into a 10 mm square, and the conductive film surface of the oriented sintered plate is made of an epoxy resin-based conductive adhesive in which conductive carbon is dispersed. By fixing on a current collector plate (positive electrode outer packaging material, 13 mm square, thickness 100 μm), a flat plate-like laminated positive electrode plate / conductive adhesive / positive electrode outer packaging layer plate was obtained.
（２ｃ）固体電解質層の形成
　直径４インチ（約１０ｃｍ）のリン酸リチウム焼結体ターゲットを準備した。このターゲットに対して、スパッタリング装置（キャノンアネルバ製、ＳＰＦ－４３０Ｈ）を用いてＲＦマグネトロン方式にてガス種Ｎ２を０．２Ｐａ、出力０．２ｋＷの条件にて衝突させて上記配向正極板の板表面に薄膜を設けるスパッタリングを行なった。こうして、配向正極板上に、膜厚３．５μｍのＬｉＰＯＮ（リン酸リチウムオキシナイトライドガラス電解質）系の固体電解質スパッタ膜を固体電解質層として形成した。 (2c) Formation of Solid Electrolyte Layer A lithium phosphate sintered compact target having a diameter of 4 inches (about 10 cm) was prepared. Using this sputtering apparatus (Canon Anelva, SPF-430H), a gas type N 2 was collided with an RF magnetron method under the conditions of 0.2 Pa and an output of 0.2 kW, and the above-mentioned aligned positive electrode plate Sputtering was performed to provide a thin film on the plate surface. Thus, a LiPON (lithium phosphate oxynitride glass electrolyte) -based solid electrolyte sputtered film having a film thickness of 3.5 μm was formed as a solid electrolyte layer on the oriented positive electrode plate.
（２ｄ）負極層の形成
　リチウム金属を載せたタングステンボートを準備した。真空蒸着装置（サンユー電子製、カーボンコーターＳＶＣ－７００）を用いて、抵抗加熱によりＬｉを蒸発させて上記固体電解質層の表面に薄膜を設ける蒸着を行った。このとき、マスクを用いて負極層のサイズを９．５ｍｍ角として、負極層が１０ｍｍ角の正極領域内に収まるようにした。こうして、固体電解質層上に膜厚１０μｍのＬｉ蒸着膜を負極層として形成した単電池を作製した。 (2d) Formation of negative electrode layer A tungsten boat on which lithium metal was placed was prepared. Using a vacuum deposition apparatus (Sanyu Denshi, carbon coater SVC-700), evaporation was performed by evaporating Li by resistance heating and forming a thin film on the surface of the solid electrolyte layer. At this time, using a mask, the size of the negative electrode layer was set to 9.5 mm square so that the negative electrode layer was within the 10 mm square positive electrode region. In this way, a unit cell was produced in which a Li-deposited film having a thickness of 10 μm was formed as a negative electrode layer on the solid electrolyte layer.
（２ｅ）端部封止部の作製
　上記単電池の端部（正極集電板の外周部）に、変性ポリプロピレン樹脂フィルム（厚さ１００μｍ）を積層することにより、端部封止部を作製した。 (2e) Production of end sealing portion An end sealing portion was produced by laminating a modified polypropylene resin film (thickness: 100 μm) on the end portion of the unit cell (the outer peripheral portion of the positive electrode current collector plate). .
（２ｆ）負極集電体（負極外装材）の積層
　上記単電池の負極層上に、負極集電体（負極外装材）として厚さ２０μｍのステンレス集電板を積層し、減圧下、２００℃のホットプレートを使用して加熱圧着した。こうして全固体リチウム電池を得た。 (2f) Lamination of negative electrode current collector (negative electrode exterior material) On the negative electrode layer of the unit cell, a stainless current collector plate having a thickness of 20 μm was laminated as a negative electrode current collector (negative electrode exterior material), and the pressure was reduced to 200 ° C. And hot pressing using a hot plate. Thus, an all solid lithium battery was obtained.
（３）電池評価
　全固体リチウム電池を０．１ｍＡ定電流で４．１Ｖまで充電し、その後定電圧で電流が０．０２ｍＡになるまで充電して、充電容量を得た。その後、０．１ｍＡ定電流で３．０Ｖまで放電した。この操作を５０回繰り返した。放電開始から１０秒後のＩＲドロップから電池の内部抵抗Ｒを算出し、５回目の放電時の内部抵抗をＲ５、５０回目の放電時の内部抵抗Ｒ５０とした。Ｒ５０をＲ５で除した値を抵抗変化率とした。５つの電池を作製及び評価し、その平均を取ったところ、抵抗変化率は２２０％であった。 (3) Battery evaluation The all-solid-state lithium battery was charged to 4.1 V at a constant current of 0.1 mA, and then charged to a current of 0.02 mA at a constant voltage to obtain a charge capacity. Then, it discharged to 3.0V with a 0.1 mA constant current. This operation was repeated 50 times. The internal resistance R of the battery was calculated from the IR drop 10 seconds after the start of discharge, and the internal resistance at the fifth discharge was R 5 and the internal resistance R 50 at the 50th discharge. To R 50 have the value obtained by dividing the rate of change in resistance R 5. When five batteries were produced and evaluated and the average was taken, the resistance change rate was 220%.
　例Ｂ２（比較）
　本例は、（１０４）面が板面に対して平行に配向した（すなわち（００３）面が板面と平行に配向していない）配向正極板が集電板へ接着されていない状態の全固体リチウム電池を作製及び評価した比較例である。 Example B2 (comparison)
In this example, the (104) plane is aligned in parallel with the plate surface (that is, the (003) plane is not aligned in parallel with the plate surface) and the aligned positive plate is not bonded to the current collector plate. It is the comparative example which produced and evaluated the solid lithium battery.
（１）配向正極板の作製
（１ａ）グリーンシートの作製
　Ｃｏ３Ｏ４原料粉末（体積基準Ｄ５０粒径０．３μｍ、正同化学工業株式会社製）に５ｗｔ％の割合でＢｉ２Ｏ３（体積基準Ｄ５０粒径０．３μｍ、太陽鉱工株式会社製）を添加して混合粉末を得た。この混合粉末１００重量部と、分散媒（トルエン：イソプロパノール＝１：１）１００重量部と、バインダー（ポリビニルブチラール：品番ＢＭ－２、積水化学工業株式会社製）１０重量部と、可塑剤（ＤＯＰ：ジ（２－エチルヘキシル）フタレート、黒金化成株式会社製）４重量部と、分散剤（製品名レオドールＳＰ－Ｏ３０、花王株式会社製）２重量部とを混合した。この混合物を、減圧下で撹拌することで脱泡するとともに、４０００ｃＰの粘度に調整した。なお、粘度は、ブルックフィールド社製ＬＶＴ型粘度計で測定した。上記のようにして調製されたスラリーを、ドクターブレード法によって、ＰＥＴ（ポリエチレンテレフタレート）フィルムの上に、乾燥後の厚さが４０μｍとなるように、シート状に成形してグリーンシートを得た。 (1) Preparation of oriented positive electrode plate (1a) Preparation of green sheet Bi 2 O 3 (Co 2 O 3 raw material powder (volume basis D50 particle size 0.3 μm, manufactured by Shodo Chemical Industry Co., Ltd.)) Volume standard D50 particle size 0.3 μm, manufactured by Taiyo Mining Co., Ltd.) was added to obtain a mixed powder. 100 parts by weight of the mixed powder, 100 parts by weight of a dispersion medium (toluene: isopropanol = 1: 1), 10 parts by weight of a binder (polyvinyl butyral: product number BM-2, manufactured by Sekisui Chemical Co., Ltd.), and a plasticizer (DOP : 4 parts by weight of di (2-ethylhexyl) phthalate (manufactured by Kurokin Kasei Co., Ltd.) and 2 parts by weight of a dispersant (product name: Leodol SP-O30, Kao Corporation) were mixed. The mixture was defoamed by stirring under reduced pressure and adjusted to a viscosity of 4000 cP. The viscosity was measured with an LVT viscometer manufactured by Brookfield. The slurry prepared as described above was formed into a sheet shape on a PET (polyethylene terephthalate) film so that the thickness after drying was 40 μm by a doctor blade method to obtain a green sheet.
（１ｂ）配向焼結板の作製
　例Ｂ１と同様の手順により、厚さ４５μｍからなるＬｉＣｏＯ２配向焼結板を配向正極板として得た。 (1b) Preparation of Oriented Sintered Plate A LiCoO 2 oriented sintered plate having a thickness of 45 μm was obtained as an oriented positive plate by the same procedure as in Example B1.
（２）全固体リチウム電池の作製
（２ａ）導電膜の作製及び配向正極板の切り出し
　イオンスパッタリング装置（日本電子製、ＪＦＣ－１５００）を用いたスパッタリングにより、コバルト酸リチウム配向正極板の片面に厚さ１０００ÅのＡｕ膜を導電膜として形成した。さらに、配向正極板を１０ｍｍ角に切り出した。 (2) Production of all-solid-state lithium battery (2a) Production of conductive film and cutting of oriented positive plate Thickness on one side of a lithium cobaltate oriented positive plate by sputtering using an ion sputtering apparatus (JFC-1500, manufactured by JEOL Ltd.) A 1000 Ａｕ thick Au film was formed as a conductive film. Furthermore, the oriented positive electrode plate was cut into a 10 mm square.
（２ｂ）固体電解質層の形成
　直径４インチ（約１０ｃｍ）のリン酸リチウム焼結体ターゲットを準備した。このターゲットに対して、スパッタリング装置（キャノンアネルバ製、ＳＰＦ－４３０Ｈ）を用いてＲＦマグネトロン方式にてガス種Ｎ２を０．２Ｐａ、出力０．２ｋＷの条件にて衝突させて上記配向正極板の板表面に薄膜を設けるスパッタリングを行なった。こうして、配向正極板上に、膜厚３．５μｍのＬｉＰＯＮ（リン酸リチウムオキシナイトライドガラス電解質）系の固体電解質スパッタ膜を固体電解質層として形成した。 (2b) Formation of solid electrolyte layer A lithium phosphate sintered compact target having a diameter of 4 inches (about 10 cm) was prepared. Using this sputtering apparatus (Canon Anelva, SPF-430H), a gas type N 2 was collided with an RF magnetron method under the conditions of 0.2 Pa and an output of 0.2 kW, and the above-mentioned aligned positive electrode plate Sputtering was performed to provide a thin film on the plate surface. Thus, a LiPON (lithium phosphate oxynitride glass electrolyte) -based solid electrolyte sputtered film having a film thickness of 3.5 μm was formed as a solid electrolyte layer on the oriented positive electrode plate.
（２ｃ）負極層の形成
　リチウム金属を載せたタングステンボートを準備した。真空蒸着装置（サンユー電子製、カーボンコーターＳＶＣ－７００）を用いて、抵抗加熱によりＬｉを蒸発させて上記中間層の表面に薄膜を設ける蒸着を行った。このとき、マスクを用いて負極層のサイズを９．５ｍｍ角として、負極層が１０ｍｍ角の正極領域内に収まるようにした。こうして、固体電解質層上に膜厚１０μｍのＬｉ蒸着膜を負極層として形成した単電池を作製した。 (2c) Formation of negative electrode layer A tungsten boat on which lithium metal was placed was prepared. Using a vacuum deposition apparatus (carbon coater SVC-700, manufactured by Sanyu Denshi), vapor deposition was performed in which Li was evaporated by resistance heating to form a thin film on the surface of the intermediate layer. At this time, using a mask, the size of the negative electrode layer was set to 9.5 mm square so that the negative electrode layer was within the 10 mm square positive electrode region. In this way, a unit cell was produced in which a Li-deposited film having a thickness of 10 μm was formed as a negative electrode layer on the solid electrolyte layer.
（２ｄ）外装封止
　厚さ２０μｍのステンレス箔を１３ｍｍ角に切り出して正極集電板とした。また、外縁形状が１３ｍｍ角で、その内側に１１ｍｍ角の孔が打ち抜かれた、１ｍｍ幅の枠状の変性ポリプロピレン樹脂フィルム（厚さ１００μｍ）を用意した。この枠状の樹脂フィルムを正極集電板上の外周部に積層し、加熱圧着して端部封止部を形成した。正極集電板上の端部封止部で囲まれた領域内に上記単電池を載置した。載置した単電池の負極側にも上記同様に厚さ２０μｍのステンレス箔を載置し、端部封止部に対して荷重を加えながら、減圧下、２００℃で加熱した。こうして外周全体にわたって端部封止部と上下２枚のステンレス箔とを貼り合せて単電池を封止した。こうして、封止形態の全固体リチウム電池を得た。こうして得られた電池は、配向正極板が集電板へ接着されていない状態のものである。すなわち、得られた電池は、正極集電体が、配向正極板の固体電解質層と反対側の面に、接着剤を含まない非接着状態で全面的に接触されているものである。 (2d) Exterior sealing A stainless foil having a thickness of 20 μm was cut into a 13 mm square to form a positive electrode current collector plate. Also, a 1 mm wide frame-shaped modified polypropylene resin film (thickness: 100 μm) having an outer edge shape of 13 mm square and an 11 mm square hole punched inside thereof was prepared. This frame-shaped resin film was laminated on the outer peripheral portion on the positive electrode current collector plate, and heat-pressed to form an end sealing portion. The unit cell was placed in a region surrounded by the end sealing portion on the positive electrode current collector plate. Similarly to the above, a stainless steel foil having a thickness of 20 μm was placed on the negative electrode side of the placed unit cell, and heated at 200 ° C. under reduced pressure while applying a load to the end sealing portion. Thus, the end sealing part and the upper and lower two stainless steel foils were bonded together over the entire outer periphery to seal the unit cell. Thus, an all solid lithium battery in a sealed form was obtained. The battery thus obtained is in a state where the aligned positive electrode plate is not bonded to the current collector plate. That is, in the obtained battery, the positive electrode current collector is entirely in contact with the surface of the oriented positive electrode plate opposite to the solid electrolyte layer in a non-adhesive state that does not contain an adhesive.
（３）電池評価
　上記のようにして得られた全固体リチウム電池５個を例Ｂ１と同様にして評価したところ、すべてサイクル途中で漏れ電流が発生したため、不良品と判定した。 (3) Battery evaluation When five all-solid-state lithium batteries obtained as described above were evaluated in the same manner as in Example B1, leakage current was generated in the middle of the cycle.
　例Ｂ３
　本例は、（００３）面が板面と平行に配向した配向正極板が集電板へ接着されていない状態の全固体リチウム電池を作製及び評価した実施例である。 Example B3
This example is an example in which an all-solid-state lithium battery was prepared and evaluated in a state in which an oriented positive plate with the (003) plane oriented parallel to the plate surface was not bonded to the current collector plate.
（１）配向正極板の作製
　例Ａ２と同様にして、表１に示される条件に従い、（００３）面が板面と平行に配向した配向正極板を作製した。得られた配向正極板の特性は表２に示されるとおりである。 (1) Production of Oriented Positive Electrode Plate In the same manner as in Example A2, an oriented positive plate having a (003) plane oriented parallel to the plate surface was produced according to the conditions shown in Table 1. The characteristics of the obtained oriented positive electrode plate are as shown in Table 2.
（２）全固体リチウム電池の作製
　上記（１）で得られたコバルト酸リチウム配向正極板を用いたこと以外は、例Ｂ２と同様にして、封止形態の全固体リチウム電池を得た。こうして得られた電池は、配向正極板が集電板へ接着されていない状態のものである。すなわち、得られた電池は、正極集電体が、配向正極板の固体電解質層と反対側の面に、接着剤を含まない非接着状態で全面的に接触されているものである。 (2) Production of all-solid lithium battery An all-solid lithium battery in a sealed form was obtained in the same manner as in Example B2, except that the lithium cobaltate oriented positive plate obtained in (1) above was used. The battery thus obtained is in a state where the aligned positive electrode plate is not bonded to the current collector plate. That is, in the obtained battery, the positive electrode current collector is entirely in contact with the surface of the oriented positive electrode plate opposite to the solid electrolyte layer in a non-adhesive state that does not contain an adhesive.
（３）電池評価
　上記のようにして得られた全固体リチウム電池５個を例Ｂ１と同様にして評価したところ、抵抗増加率は１２０％であった。

  (3) Battery evaluation When five all solid lithium batteries obtained as described above were evaluated in the same manner as in Example B1, the rate of increase in resistance was 120%.

Claims (14)

  1. 　配向焼結体からなる厚さ２０μｍ以上の自立した配向正極板であって、前記配向焼結体が層状岩塩構造を有するリチウム複合酸化物で構成される複数の結晶粒を含み、前記複数の結晶粒は（００３）面が前記配向正極板の板面に対して平行に配向している、配向正極板と、
    　前記配向正極板上に設けられ、リチウムイオン伝導材料で構成される固体電解質層と、
    　前記固体電解質層上に設けられる、リチウムを含む負極層と、
    　前記配向正極板の前記固体電解質層と反対側の面に、接着剤を含まない非接着状態で全面的に接触されている、厚さ５μｍ以上３０μｍ以下の金属箔である正極集電体と、
    を備えた、全固体リチウム電池。     A self-supporting oriented positive electrode plate having a thickness of 20 μm or more comprising an oriented sintered body, wherein the oriented sintered body includes a plurality of crystal grains composed of a lithium composite oxide having a layered rock salt structure, and the plurality of crystals The grains have a (003) plane oriented parallel to the plate surface of the oriented positive plate;
    A solid electrolyte layer provided on the oriented positive electrode plate and made of a lithium ion conductive material;
    A negative electrode layer containing lithium provided on the solid electrolyte layer;
    A positive electrode current collector which is a metal foil having a thickness of 5 μm or more and 30 μm or less, which is in full contact with the surface opposite to the solid electrolyte layer of the oriented positive electrode plate in a non-adhesive state not containing an adhesive;
    An all-solid-state lithium battery.
  2. 　前記配向正極板の厚さが２０～１００μｍである、請求項１に記載の全固体リチウム電池。 2. The all-solid-state lithium battery according to claim 1, wherein the orientation positive electrode plate has a thickness of 20 to 100 μm.
  3. 　前記配向焼結体の断面を電子線後方散乱回折法（ＥＢＳＤ）により解析した場合に、解析された前記断面に含まれる結晶粒のうち前記板面に対する（００３）面の角度が０°超３０°以下である結晶粒の合計面積が、前記断面に含まれる結晶粒の総面積に対して７０％以上である、請求項１又は２に記載の全固体リチウム電池。 When the cross section of the oriented sintered body is analyzed by electron beam backscatter diffraction (EBSD), the angle of the (003) plane with respect to the plate surface among the crystal grains included in the analyzed cross section is more than 0 ° 30 3. The all-solid-state lithium battery according to claim 1, wherein the total area of crystal grains that is less than or equal to 70 ° is 70% or more with respect to the total area of crystal grains included in the cross section.
  4. 　前記リチウム複合酸化物がコバルト酸リチウムである、請求項１～３のいずれか一項に記載の全固体リチウム電池。 The all-solid-state lithium battery according to any one of claims 1 to 3, wherein the lithium composite oxide is lithium cobalt oxide.
  5. 　前記焼結体の緻密度が９０％以上である、請求項１～４のいずれか一項に記載の全固体リチウム電池。 The all-solid-state lithium battery according to any one of claims 1 to 4, wherein a density of the sintered body is 90% or more.
  6. 　前記配向正極板が、前記固体電解質層と反対側の面に、厚さ０．０１μｍ以上５μｍ未満の導電膜をさらに備える、請求項１～５のいずれか一項に記載の全固体リチウム電池。 6. The all-solid-state lithium battery according to claim 1, wherein the oriented positive electrode plate further includes a conductive film having a thickness of 0.01 μm or more and less than 5 μm on a surface opposite to the solid electrolyte layer.
  7. 　前記導電膜が金属及び／又はカーボンで構成される、請求項６に記載の全固体リチウム電池。 The all-solid-state lithium battery according to claim 6, wherein the conductive film is made of metal and / or carbon.
  8. 　前記正極集電体が、前記固体電解質層側の面にカーボン膜をさらに備える、請求項１～７のいずれか一項に記載の全固体リチウム電池。 The all-solid-state lithium battery according to any one of claims 1 to 7, wherein the positive electrode current collector further includes a carbon film on the surface on the solid electrolyte layer side.
  9. 　前記正極集電体が、前記配向正極板に対して押圧されている、請求項１～８のいずれか一項に記載の全固体リチウム電池。 The all-solid-state lithium battery according to any one of claims 1 to 8, wherein the positive electrode current collector is pressed against the oriented positive electrode plate.
  10. 　前記正極集電体の前記配向正極板に対する押圧は、前記正極集電体の内外気圧差によってもたらされている、請求項９に記載の全固体リチウム電池。 The all-solid-state lithium battery according to claim 9, wherein the positive current collector is pressed against the oriented positive electrode plate by a difference in internal and external pressures of the positive current collector.
  11. 　前記配向正極板、前記固体電解質層及び前記負極層を含む積層体が外装材で包装又は封止されており、前記正極集電体が前記外装材の一部を構成し、前記外装材で包装又は封止される前記積層体の収容空間が減圧されている、請求項１～１０のいずれか一項に記載の全固体リチウム電池。 A laminate including the oriented positive electrode plate, the solid electrolyte layer, and the negative electrode layer is packaged or sealed with an exterior material, and the positive electrode current collector constitutes a part of the exterior material and is packaged with the exterior material. Alternatively, the all-solid-state lithium battery according to any one of claims 1 to 10, wherein an accommodation space of the laminated body to be sealed is decompressed.
  12. 　前記固体電解質層を構成する前記リチウムイオン伝導材料が、ガーネット系セラミックス材料、窒化物系セラミックス材料、ペロブスカイト系セラミックス材料、リン酸系セラミックス材料、硫化物系セラミックス材料、又は高分子系材料で構成されている、請求項１～１１のいずれか一項に記載の全固体リチウム電池。 The lithium ion conductive material constituting the solid electrolyte layer is composed of a garnet ceramic material, a nitride ceramic material, a perovskite ceramic material, a phosphate ceramic material, a sulfide ceramic material, or a polymer material. The all-solid-state lithium battery according to any one of claims 1 to 11, wherein
  13. 　前記固体電解質層を構成する前記リチウムイオン伝導材料が、Ｌｉ－Ｌａ－Ｚｒ－Ｏ系セラミックス材料及び／又はリン酸リチウムオキシナイトライド（ＬｉＰＯＮ）系セラミックス材料で構成される、請求項１～１２のいずれか一項に記載の全固体リチウム電池。 The lithium ion conductive material constituting the solid electrolyte layer is composed of a Li-La-Zr-O based ceramic material and / or a lithium phosphate oxynitride (LiPON) based ceramic material. The all-solid-state lithium battery as described in any one.
  14. 　前記固体電解質層の前記負極側の面にリチウムと合金化可能な金属を含む中間層をさらに含む、請求項１～１３のいずれか一項に記載の全固体リチウム電池。

          The all-solid lithium battery according to any one of claims 1 to 13, further comprising an intermediate layer containing a metal that can be alloyed with lithium on a surface of the solid electrolyte layer on the negative electrode side.

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