WO2024070579A1 - Batterie tout solide et procédé de production correspondant - Google Patents

Batterie tout solide et procédé de production correspondant Download PDF

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Publication number
WO2024070579A1
WO2024070579A1 PCT/JP2023/032791 JP2023032791W WO2024070579A1 WO 2024070579 A1 WO2024070579 A1 WO 2024070579A1 JP 2023032791 W JP2023032791 W JP 2023032791W WO 2024070579 A1 WO2024070579 A1 WO 2024070579A1
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positive electrode
solid
negative electrode
electrode mixture
power generating
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PCT/JP2023/032791
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English (en)
Japanese (ja)
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政嗣 石澤
潤珠 青木
春樹 上剃
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マクセル株式会社
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Publication of WO2024070579A1 publication Critical patent/WO2024070579A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/04—Construction or manufacture in general
    • 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
    • H01M10/058—Construction or manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • 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
    • H01M4/80—Porous plates, e.g. sintered carriers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/528—Fixed electrical connections, i.e. not intended for disconnection
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/531—Electrode connections inside a battery casing
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/572—Means for preventing undesired use or discharge
    • H01M50/584—Means for preventing undesired use or discharge for preventing incorrect connections inside or outside the batteries
    • H01M50/586—Means for preventing undesired use or discharge for preventing incorrect connections inside or outside the batteries inside the batteries, e.g. incorrect connections of electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/572—Means for preventing undesired use or discharge
    • H01M50/584—Means for preventing undesired use or discharge for preventing incorrect connections inside or outside the batteries
    • H01M50/59—Means for preventing undesired use or discharge for preventing incorrect connections inside or outside the batteries characterised by the protection means
    • H01M50/593—Spacers; Insulating plates
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M6/00—Primary cells; Manufacture thereof
    • H01M6/02—Details
    • 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-state battery with excellent discharge characteristics and high capacity, and a method for manufacturing the same.
  • lithium batteries particularly lithium ion batteries, that can meet this demand use lithium-containing composite oxides such as lithium cobalt oxide ( LiCoO2 ) and lithium nickel oxide ( LiNiO2 ) as the positive electrode active material, graphite or the like as the negative electrode active material, and an organic electrolyte solution containing an organic solvent and a lithium salt as the non-aqueous electrolyte.
  • lithium-containing composite oxides such as lithium cobalt oxide ( LiCoO2 ) and lithium nickel oxide ( LiNiO2 ) as the positive electrode active material, graphite or the like as the negative electrode active material, and an organic electrolyte solution containing an organic solvent and a lithium salt as the non-aqueous electrolyte.
  • lithium-ion batteries As devices that use lithium-ion batteries continue to develop, there is a demand for longer life, higher capacity, and higher energy density lithium-ion batteries, as well as a high demand for the reliability of these longer life, higher capacity, and higher energy density lithium-ion batteries.
  • the organic electrolyte used in lithium-ion batteries contains organic solvents, which are flammable substances, and so there is a possibility that the organic electrolyte may generate abnormal heat if an abnormality such as a short circuit occurs in the battery. Furthermore, with the recent trend toward higher energy density in lithium-ion batteries and an increasing amount of organic solvent in organic electrolytes, there is an even greater demand for the reliability of lithium-ion batteries.
  • All-solid-state lithium batteries that do not use organic solvents (all-solid-state batteries) are also being considered.
  • All-solid-state lithium batteries use a molded solid electrolyte that does not use organic solvents instead of the conventional organic solvent-based electrolyte, and are highly reliable with no risk of abnormal heat generation from the solid electrolyte. For this reason, there are high expectations for them, especially in product areas that require high-capacity secondary batteries.
  • Solid-state batteries are also highly reliable and environmentally resistant, and have a long lifespan, making them promising maintenance-free batteries that can contribute to social development while also continuing to contribute to safety and security.
  • Providing solid-state batteries to society can contribute to the achievement of Goal 3 (Ensure healthy lives and promote well-being for all at all ages), Goal 7 (Ensure access to affordable, reliable, sustainable and modern energy for all), Goal 11 (Make cities and human settlements inclusive, safe, resilient and sustainable), and Goal 12 (Ensure sustainable consumption and production patterns) out of the 17 Sustainable Development Goals (SDGs) established by the United Nations.
  • SDGs Sustainable Development Goals
  • All-solid-state batteries are manufactured by, for example, sequentially placing a powdered positive electrode mixture containing a positive electrode active material and a solid electrolyte, a powdered solid electrolyte, and a powdered negative electrode mixture containing a negative electrode active material and a solid electrolyte in a processing jig and pressurizing them to form a positive electrode mixture layer, a solid electrolyte layer, and a negative electrode mixture layer, and then further pressurizing the entire laminate to increase the density of each layer and to bond the interfaces between the layers.
  • the pressure applied to the compact during compression tends to be uneven due to the insufficient fluidity of the raw material powders and frictional forces acting between the powders, resulting in density variations within each layer.
  • localized unevenness in the degree of contact between the active material and solid electrolyte occurs inside the compact, making it undesirable to obtain an all-solid-state battery with good electrical properties.
  • these density unevenness can also cause the compact to curve.
  • Patent Document 1 proposes a method for manufacturing an all-solid-state battery in which an electrode layer (laminate) consisting of a positive electrode collector, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode collector has a larger area than the electrode layer, a curvature prevention portion is formed on the outer edge of at least one of the current collectors, pressure is applied, and then the curvature prevention portion is removed together with a part of the current collector.
  • an electrode layer laminate
  • an electrode layer consisting of a positive electrode collector, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode collector has a larger area than the electrode layer
  • a curvature prevention portion is formed on the outer edge of at least one of the current collectors, pressure is applied, and then the curvature prevention portion is removed together with a part of the current collector.
  • a collector with an excessively large area is used compared to the area of the electrode layer, resulting in waste of material.
  • a collector with a side length of 160 mm is used for a square electrode layer with a side length of 100 mm, resulting in a waste of more than half of the material.
  • the curvature prevention part must be changed to match these conditions, but this adjustment is not easy.
  • Patent Document 2 proposes an all-solid-state secondary battery in which a thin sheet-like battery element with a relatively small surface area, in which a positive electrode, a solid electrolyte, and a negative electrode are sequentially laminated, is arranged on a current collector at specific intervals to suppress deterioration of characteristics caused by expansion and contraction of the electrodes and brittle fracture due to impact.
  • Patent Document 2 has the potential to increase the overall capacity of the battery while avoiding the manufacture of battery elements with non-uniform internal density.
  • the demand for improved characteristics in recent all-solid-state batteries is increasing day by day, and from this perspective, there is still room for improvement in the technology described in Patent Document 2.
  • JP 2018-125268 A (claims, paragraphs [0033] to [0035], etc.)
  • JP 2001-15153 A (claims, paragraphs [0025] to [0027], [0037], etc.)
  • the present invention was made in consideration of the above circumstances, and its purpose is to provide an all-solid-state battery with excellent discharge characteristics and high capacity, and a manufacturing method thereof.
  • a first aspect of the all-solid-state battery of the present invention is characterized in that a plurality of power generation elements are arranged, each of the power generation elements having a positive electrode, a negative electrode, and a solid electrolyte layer disposed between the positive electrode and the negative electrode, the thickness t (mm) of the power generation element is 0.5 to 6.0 mm, the area S ( mm2 ) of the power generation element in a plan view is 10 to 1000 mm, and the positive electrodes of the plurality of power generation elements are directly connected to each other by current collectors, and the negative electrodes of the plurality of power generation elements are directly connected to each other by current collectors.
  • a second aspect of the all-solid-state battery of the present invention is characterized in that a plurality of power generation elements are arranged, the power generation elements are formed by stacking a plurality of unit laminate electrode bodies each formed by stacking a positive electrode, a negative electrode, and a solid electrolyte layer disposed between the positive electrode and the negative electrode, the thickness t2 (mm) of each of the unit laminate electrode bodies is 0.5 to 6.0, the area S2 ( mm2 ) in a plan view of each of the unit laminate electrode bodies is 10 to 1000, and the outermost positive electrodes of each of the plurality of power generation elements are directly connected to each other by a current collector, and the outermost negative electrodes of each of the plurality of power generation elements are directly connected to each other by a current collector.
  • each of the multiple power generation elements, or each unit laminate electrode body constituting the multiple power generation elements can have a positive electrode having a positive electrode mixture layer and a negative electrode having a negative electrode mixture layer.
  • Such an all-solid-state battery can be manufactured by the manufacturing method of the present invention having a power generation element formation process or a unit laminate electrode body formation process including a process of pressurizing a powdered positive electrode mixture to form the positive electrode mixture layer, a process of pressurizing a powdered solid electrolyte to form a solid electrolyte layer, and a process of pressurizing a powdered negative electrode mixture to form the negative electrode mixture layer.
  • the present invention provides an all-solid-state battery with excellent discharge characteristics and high capacity, as well as a manufacturing method thereof.
  • FIG. 1 is a cross-sectional view illustrating a schematic example of an all-solid-state battery of the present invention.
  • 1 is a diagram for explaining a state in which a plurality of power generating elements are arranged using a frame.
  • 1 is a diagram for explaining a state in which a plurality of power generating elements are arranged using a frame.
  • 1 is a diagram for explaining a state in which a plurality of power generating elements are arranged using a frame.
  • 1 is a scanning electron microscope photograph of a surface (positive electrode surface) of an example of a power generating element.
  • FIG. 1 is a perspective view illustrating an example of an all-solid-state battery of the present invention.
  • FIG. 1 shows a schematic longitudinal cross-sectional view of an example of an all-solid-state battery of the present invention.
  • the all-solid-state battery 100 shown in FIG. 1 is configured by encapsulating three power generating elements 110 in an exterior body 150.
  • the power generating elements 110 have a positive electrode 120, a negative electrode 130, and a solid electrolyte layer 140 interposed between them.
  • the exterior body 150 is composed of substrates 160 and 170.
  • Three power generating elements 110 are arranged on the substrates 160 and 170.
  • the substrate 160 has an insulating layer 161 and a conductive layer 162, and the conductive layer 162 functions as a current collector on the positive electrode side. That is, the positive electrodes 120 of the three power generating elements 110 are in direct contact with the conductive layer 162 of the substrate 160, respectively, and thus the positive electrodes 120 of the three power generating elements 110 are directly connected to each other by the conductive layer 162, which is a current collector.
  • a connection terminal 180 for connecting the positive electrode of the all-solid-state battery 100 to an external device is connected to the conductive layer 162.
  • the substrate 170 also has an insulating layer 171 and a conductive layer 172, and the conductive layer 172 functions as a current collector on the negative electrode side. That is, the negative electrodes 130 of the three power generating elements 110 are in direct contact with the conductive layer 172 of the substrate 170, respectively, and as a result, the negative electrodes 130 of the three power generating elements 110 are directly connected to each other by the conductive layer 172, which is a current collector.
  • a connection terminal 190 for connecting the negative electrode of the all-solid-state battery 100 to an external device is also connected to the conductive layer 172.
  • a plurality of power generation elements are arranged. That is, for example, the area of each individual power generation element in a plan view is reduced to prevent uneven density in each layer (positive electrode, solid electrolyte layer, and negative electrode) caused by pressure spots during the formation of the power generation element, improving the characteristics, and by arranging a plurality of such power generation elements inside, it is possible to increase the capacity of the entire all-solid-state battery.
  • each power generating element has an area S (mm 2 ) in a plan view of 10 mm 2 or more, preferably 100 mm 2 or more.
  • the capacity of each power generating element becomes an appropriate value, so that the number of power generating elements to be arranged can be reduced, and the manufacturing efficiency of the all-solid-state battery can be improved.
  • the area S in a plan view of each power generating element is 1000 mm 2 or less, preferably 800 mm 2 or less.
  • each power generating element has a thickness t (mm) of 0.5 mm or more, preferably 1.0 mm or more.
  • t mm
  • the all-solid-state battery can have a high capacity even if the number of power generating elements used is reduced, the manufacturing efficiency of the all-solid-state battery can also be improved.
  • the thickness t of each power generating element is 6.0 mm or less, preferably 5.5 mm or less, and more preferably 5.0 mm or less.
  • the ratio S/t (mm) of the area S to the thickness t in a plan view of each power generating element is preferably 300 or less, more preferably 200 or less. This can improve the discharge characteristics of each power generating element, and therefore the discharge characteristics of the all-solid-state battery can be further improved. If S/t (mm) is large, cracks and deformations are likely to occur during molding of the electrode layer, and even if there are no apparent cracks, cracks and density unevenness may occur inside the electrode layer, significantly reducing electrical conductivity and causing a decrease in charge and discharge performance.
  • each layer related to the power generating element can be better molded, and the uniformity of density can be improved, and the discharge characteristics of each power generating element can be improved, and therefore the discharge characteristics of the all-solid-state battery can be further improved.
  • S/t is preferably 10 or more.
  • each unit laminate electrode body has an area S2 ( mm2 ) in a plan view of 10 mm2 or more, preferably 100 mm2 or more.
  • the capacity of each power generating element formed by these unit laminate electrode bodies becomes an appropriate value, so that the number of power generating elements to be arranged can be reduced, and the manufacturing efficiency of the all-solid-state battery can be improved.
  • the area S2 in a plan view of each unit laminate electrode body is 1000 mm2 or less, preferably 800 mm2 or less.
  • each unit laminated electrode body has a thickness t 2 (mm) of 0.5 mm or more, preferably 1.0 mm or more.
  • the thickness t 2 of each unit laminated electrode body is 6.0 mm or less, preferably 5.5 mm or less, and more preferably 5.0 mm or less.
  • the ratio S 2 /t 2 (mm) of the area S 2 to the thickness t 2 in a plan view of each unit laminate electrode body is preferably 300 or less, more preferably 200 or less. This can improve the discharge characteristics of each unit laminate electrode body, and the discharge characteristics of each power generation element composed of these are also improved, making it possible to further improve the discharge characteristics of the all-solid-state battery. If S 2 /t 2 (mm) is large, cracks and deformations are likely to occur during molding of the electrode layer body, and even if there are no apparent cracks, cracks and density unevenness will occur inside the electrode layer body, causing a significant decrease in electrical conductivity and a decrease in charge and discharge performance.
  • each layer related to the unit laminate electrode body can be better molded and the uniformity of density can be improved, and each unit laminate electrode body can be made better, making it possible to further improve the discharge characteristics of the all-solid-state battery.
  • S 2 /t 2 is preferably 10 or more.
  • the area S of the power generating element in a plan view and the area S2 of the unit laminated electrode body in a plan view refer to the area in a plan view at the location where all of the laminated positive electrodes, solid electrolyte layers, and negative electrodes are present in a direction parallel to the lamination direction of each layer of the power generating element or unit laminated electrode body.
  • a cylindrical electrode layer body it is obtained from the area of the circle, and in the case of a prismatic electrode layer body, it is obtained from the area of the rectangle.
  • CT computer tomography
  • the thickness t of the power generating element means the thickness of the power generating element including all of the porous metal substrate, the positive electrode layer, the solid electrolyte layer, and the negative electrode layer obtained by pressure molding, excluding the current collecting element to be connected after pressure molding
  • the thickness t2 of the unit laminate electrode body means the thickness of the unit laminate electrode body including all of the porous metal substrate, the positive electrode layer, the solid electrolyte layer, and the negative electrode layer obtained by pressure molding, excluding the current collecting element to be connected after pressure molding.
  • the thickness t and the thickness t2 can also be determined by CT, and in that case, they are the maximum values of the length in the stacking direction in a group of cross-sectional images parallel to the stacking direction of the power generating element or unit laminate electrode body obtained by MPR in the same manner as above (the values described in the examples below are values determined by this method).
  • the positive electrode 120 has a positive electrode mixture layer 121 and a porous metal substrate 122, and the entire porous metal substrate 122, including the end on the positive electrode mixture layer 121 side, is embedded in the surface layer of the positive electrode mixture layer 121. That is, the entire location of the porous metal substrate 122 corresponds to the region where the positive electrode mixture layer and the porous metal substrate coexist. Furthermore, in the positive electrode 120, the end of the porous metal substrate 122 on the opposite side to the positive electrode mixture layer 121 side (the lower end in FIG. 1) is exposed.
  • the dotted line in the positive electrode 120 indicates the boundary between the region in the positive electrode mixture layer 121 where the porous metal substrate does not coexist and the region where the positive electrode mixture layer and the porous metal substrate coexist, and corresponds to the end of the porous metal substrate 122 on the positive electrode mixture layer 121 side.
  • the negative electrode 130 has a negative electrode mixture layer 131 and a porous metal substrate 132, and the entirety of the porous metal substrate 132, including the end on the negative electrode mixture layer 131 side, is embedded in the surface layer of the negative electrode mixture layer 131. That is, the entirety of the location of the porous metal substrate 132 corresponds to the region where the negative electrode mixture layer and the porous metal substrate coexist. Furthermore, in the negative electrode 130, the end of the porous metal substrate 132 on the opposite side to the negative electrode mixture layer 131 side (the upper end in FIG. 1) is exposed.
  • the dotted line in the negative electrode 130 indicates the boundary between the region in the negative electrode mixture layer 131 where the porous metal substrate does not coexist and the region where the negative electrode mixture layer and the porous metal substrate coexist, and corresponds to the end of the porous metal substrate 132 on the negative electrode mixture layer 131 side.
  • the positive electrode has a positive electrode mixture layer and a sheet-shaped porous metal substrate arranged on the surface of the positive electrode mixture layer, and at least a portion of the porous metal substrate of the positive electrode, including the end on the positive electrode mixture layer side, is embedded in the surface layer of the positive electrode mixture layer to be integrated with the positive electrode mixture layer, and the other end of the porous metal substrate of the positive electrode is preferably exposed on the surface of the positive electrode, and the negative electrode has a negative electrode mixture layer and a sheet-shaped porous metal substrate arranged on the surface of the negative electrode mixture layer, and at least a portion of the porous metal substrate of the negative electrode, including the end on the negative electrode mixture layer side, is embedded in the surface layer of the negative electrode mixture layer to be integrated with the negative electrode mixture layer, and the other end of the porous metal substrate of the negative electrode is preferably exposed on the surface of the negative electrode.
  • the positive electrode of the power generating element has a positive electrode mixture layer and a sheet-like porous metal substrate arranged on the surface of the positive electrode mixture layer, and at least a portion of the porous metal substrate of the positive electrode, including the end portion on the positive electrode mixture layer side, is embedded in the surface layer of the positive electrode mixture layer and is integrated with the positive electrode mixture layer, and the other end portion of the porous metal substrate of the positive electrode is exposed on the surface of the positive electrode, it is possible to achieve good electrical connection between the sheet-like porous metal substrate that functions as a positive electrode current collector in the power generating element and the positive electrode mixture layer, and also good electrical connection between the sheet-like porous metal substrate and the current collector that connects the positive electrodes to each other.
  • the negative electrode of the power generation element has a negative electrode mixture layer and a sheet-shaped porous metal substrate arranged on the surface of the negative electrode mixture layer, and at least a portion of the porous metal substrate of the negative electrode, including the end on the negative electrode mixture layer side, is embedded in the surface layer of the negative electrode mixture layer and integrated with the negative electrode mixture layer, and the other end of the porous metal substrate of the negative electrode is exposed on the surface of the negative electrode, the electrical connection between the sheet-shaped porous metal substrate that functions as a current collector of the negative electrode in the power generation element and the negative electrode mixture layer, and the electrical connection between the sheet-shaped porous metal substrate and the current collector that connects the negative electrodes together can be improved. Therefore, since the electrical connection between the power generation elements can be improved without individually packaging each power generation element, it is possible to obtain an all-solid-state battery that has higher reliability of electrical connection and can exhibit better characteristics.
  • insulators 200 are arranged between the power generating elements 110, to the left of the power generating element 110 arranged at the left end of the figure, and to the right of the power generating element 110 arranged at the right end of the figure.
  • an insulator is arranged in at least a part of the area where the power generating elements are not arranged. This makes it possible to effectively suppress the occurrence of a short circuit due to misalignment of the power generating elements and contact between the positive electrode side current collector and the negative electrode side current collector during the manufacture and use of the all-solid-state battery.
  • an insulating layer (such as a resin film) can be provided on the side of at least a portion of the power generating element to prevent direct contact between adjacent power generating elements. This can also be used to effectively prevent misalignment of the power generating element and the occurrence of short circuits due to contact between the positive electrode collector and the negative electrode collector during the manufacture and use of the all-solid-state battery.
  • a frame made of an insulating material and having multiple openings can be used, and each of the multiple power generating elements can be placed within the openings of the frame.
  • the insulator it is possible to effectively prevent the power generating elements from shifting in position and the occurrence of short circuits due to contact between the positive electrode collector and the negative electrode collector during the manufacture and use of the all-solid-state battery.
  • Figures 2 to 4 are plan views illustrating a frame made of an insulating material and having multiple openings in which multiple power generating elements are arranged.
  • Figures 2 and 3 show multiple power generating elements 110 that are circular in plan view and arranged within the openings of frame 210, while Figure 4 shows multiple power generating elements 110 that are square in plan view and arranged within the openings of frame 210.
  • the locations where each power generating element 110 is arranged correspond to the openings.
  • the power generating element has a positive electrode, a negative electrode, and a solid electrolyte layer interposed between them.
  • the positive electrode has, for example, a positive electrode mixture layer containing a positive electrode active material and the like, and a sheet-like porous metal substrate that functions as a current collector.
  • the positive electrode active material can be the same as the positive electrode active material used in conventionally known non-aqueous electrolyte primary batteries.
  • manganese dioxide, lithium-containing manganese oxide e.g., LiMn 3 O 6 , or a composite oxide having the same crystal structure as manganese dioxide ( ⁇ -type, ⁇ -type, or a structure in which ⁇ -type and ⁇ -type are mixed, etc.
  • lithium-containing composite oxide such as Li a Ti 5/3 O 4 (4/3 ⁇ a ⁇ 7/3); vanadium oxide; niobium oxide; titanium oxide; sulfides such as iron disulfide; graphite fluoride; silver sulfides such as Ag 2 S; nickel oxide such as NiO 2 : and the like can be mentioned.
  • the positive electrode active material may be the same as the positive electrode active material used in conventionally known non-aqueous electrolyte secondary batteries, etc.
  • a spinel-type lithium manganese composite oxide represented by Li 1-x M r Mn 2-r O 4 (wherein M is at least one element selected from the group consisting of Li, Na, K, B, Mg, Ca, Sr, Ba, Ti, V, Cr, Zr, Fe, Co, Ni, Cu, Zn, Al, Sn, Sb, In, Nb, Ta, Mo, W, Y, Ru, and Rh, and 0 ⁇ x ⁇ 1, 0 ⁇ r ⁇ 1)
  • Li r Mn (1-s-t) Ni s M t O (2-u) F v a layered compound represented by Li 1-x Co 1-r M r O 2 (wherein M is at least one element selected from the group consisting of Co, Mg, Al, B, Ti, V, Cr, Fe
  • the average particle size of the positive electrode active material is preferably 1 ⁇ m or more, more preferably 2 ⁇ m or more, and preferably 10 ⁇ m or less, more preferably 8 ⁇ m or less.
  • the positive electrode active material may be either primary particles or secondary particles formed by agglomeration of primary particles.
  • the average particle diameter of various particles means the 50% diameter value ( D50 ) in the volume-based integrated fraction when the integrated volume is calculated from particles with small particle sizes using a particle size distribution measurement device (such as the Microtrack particle size distribution measurement device "HRA9320" manufactured by Nikkiso Co., Ltd.).
  • the positive electrode active material has a reaction suppression layer on its surface to suppress reaction with the solid electrolyte contained in the positive electrode.
  • the solid electrolyte may oxidize and form a resistive layer, which may reduce the ionic conductivity in the positive electrode mixture layer.
  • the reaction suppression layer may be made of a material that has ion conductivity and can suppress the reaction between the positive electrode active material and the solid electrolyte.
  • materials that can form the reaction suppression layer include oxides containing Li and at least one element selected from the group consisting of Nb, P, B, Si, Ge, Ti and Zr, more specifically, Nb-containing oxides such as LiNbO 3 , Li 3 PO 4 , Li 3 BO 3 , Li 4 SiO 4 , Li 4 GeO 4 , LiTiO 3 , LiZrO 3 , Li 2 WO 4 and the like.
  • the reaction suppression layer may contain only one of these oxides, or may contain two or more of them, and further, a plurality of these oxides may form a composite compound. Among these oxides, it is preferable to use an Nb-containing oxide, and it is more preferable to use LiNbO 3 .
  • the reaction suppression layer is preferably present on the surface in an amount of 0.1 to 1.0 parts by mass per 100 parts by mass of the positive electrode active material. This range allows for good suppression of the reaction between the positive electrode active material and the solid electrolyte.
  • Methods for forming a reaction suppression layer on the surface of the positive electrode active material include the sol-gel method, mechanofusion method, CVD method, PVD method, and ALD method.
  • the content of the positive electrode active material in the positive electrode mixture is preferably 60 to 85 mass % in order to increase the energy density of the all-solid-state battery.
  • the positive electrode mixture can contain a conductive assistant.
  • a conductive assistant include carbon materials such as graphite (natural graphite, artificial graphite), graphene, carbon black, carbon nanofibers, and carbon nanotubes.
  • carbon materials such as graphite (natural graphite, artificial graphite), graphene, carbon black, carbon nanofibers, and carbon nanotubes.
  • the conductive assistant when the conductive assistant is contained in the positive electrode mixture, the content is preferably 1.0 parts by mass or more, preferably 7.0 parts by mass or less, and more preferably 6.5 parts by mass or less, when the content of the positive electrode active material is 100 parts by mass.
  • the positive electrode mixture may contain a binder.
  • a binder is a fluororesin such as polyvinylidene fluoride (PVDF).
  • PVDF polyvinylidene fluoride
  • the positive electrode mixture may not contain a binder if good moldability can be ensured in forming the positive electrode mixture layer without using a binder, such as when a sulfide-based solid electrolyte is contained in the positive electrode mixture (described in detail later).
  • the positive electrode mixture requires a binder, its content is preferably 15% by mass or less, and preferably 0.5% by mass or more. On the other hand, if the positive electrode mixture can obtain moldability without requiring a binder, its content is preferably 0.5% by mass or less, more preferably 0.3% by mass or less, and even more preferably 0% by mass (i.e., no binder is contained).
  • the positive electrode mixture contains a solid electrolyte.
  • the solid electrolyte contained in the positive electrode mixture is not particularly limited as long as it has lithium ion conductivity.
  • sulfide-based solid electrolytes, hydride-based solid electrolytes, halide-based solid electrolytes, oxide-based solid electrolytes, etc. can be used.
  • Examples of sulfide-based solid electrolytes include particles of Li 2 S-P 2 S 5 , Li 2 S-SiS 2 , Li 2 S -P 2 S 5 -GeS 2 , and Li 2 S -B 2 S 3 based glass.
  • thio - LISICON type electrolytes which have been attracting attention in recent years for their high Li ion conductivity , are also available .
  • M3 is Al, Ga, Y or Sb, M4 is Zn, Ca or Ba, M5 is S or either S and O, and X is F, Cl, Br or I, 0 ⁇ a ⁇ 3, 0 ⁇ b+c+d ⁇ 3, 0 ⁇ e ⁇ 3] or one having an argyrodite type crystal structure can also be used.
  • Examples of hydride-based solid electrolytes include LiBH 4 , solid solutions of LiBH 4 and the following alkali metal compounds (for example, those in which the molar ratio of LiBH 4 to the alkali metal compound is 1:1 to 20:1), etc.
  • Examples of the alkali metal compound in the solid solution include at least one selected from the group consisting of lithium halides (LiI, LiBr, LiF, LiCl, etc.), rubidium halides (RbI, RbBr, RbF, RbCl, etc.), cesium halides (CsI, CsBr, CsF, CsCl, etc.), lithium amide, rubidium amide, and cesium amide.
  • lithium halides LiI, LiBr, LiF, LiCl, etc.
  • rubidium halides RbI, RbBr, RbF, RbCl, etc.
  • cesium halides CsI, CsBr, CsF, Cs
  • Other known solid electrolytes that can be used include those described in, for example, WO 2020/070958 and WO 2020/070955.
  • oxide-based solid electrolytes examples include garnet-type Li 7 La 3 Zr 2 O 12 , NASICON-type Li 1+O Al 1+O Ti 2-O (PO 4 ) 3 and Li 1+p Al 1+p Ge 2-p (PO 4 ) 3 , and perovskite-type Li 3q La 2/3-q TiO 3 .
  • sulfide-based solid electrolytes are preferred due to their high lithium ion conductivity, sulfide-based solid electrolytes containing Li and P are more preferred, and sulfide-based solid electrolytes having an argyrodite crystal structure are even more preferred due to their higher lithium ion conductivity and high chemical stability.
  • sulfide-based solid electrolyte having an argyrodite-type crystal structure for example, one represented by the following general composition formula (1), the following general composition formula (2), or the following general composition formula (3), such as Li 6 PS 5 Cl, is particularly preferred.
  • X represents one or more halogen elements, and 0.2 ⁇ k ⁇ 2.0 or 0.2 ⁇ k ⁇ 1.8.
  • the average particle size of the solid electrolyte is preferably 0.1 ⁇ m or more, and more preferably 0.2 ⁇ m or more, from the viewpoint of reducing grain boundary resistance, while it is preferably 10 ⁇ m or less, and more preferably 5 ⁇ m or less, from the viewpoint of forming a sufficient contact interface between the active material and the solid electrolyte.
  • the content of the solid electrolyte in the positive electrode mixture is preferably 10 parts by mass or more, and more preferably 15 parts by mass or more, when the content of the positive electrode active material is 100 parts by mass.
  • the content of solid electrolyte in the positive electrode mixture is preferably 65 parts by mass or less, and more preferably 60 parts by mass or less, when the content of the positive electrode active material is 100 parts by mass.
  • a foamed metal porous body For the sheet-like porous metal substrate in the positive electrode, it is preferable to use a foamed metal porous body.
  • An example of a foamed metal porous body is "Celmet (registered trademark)" by Sumitomo Electric Industries, Ltd.
  • such a porous metal substrate usually has a thickness before use in a positive electrode (power generating element) that is greater than the thickness described above (thickness within the positive electrode) (for example, the thickness before compression is preferably 0.1 mm or more, more preferably 0.3 mm or more, and particularly preferably 0.5 mm or more, while preferably 3 mm or less, more preferably 2 mm or less, and particularly preferably 1.5 mm or less).
  • the thickness is compressed in the thickness direction to the value described below.
  • the porosity of the porous metal substrate before compression is preferably 80% or more, more preferably 90% or more, and particularly preferably 95% or more, so that the pores of the porous metal substrate can be easily filled with the positive electrode mixture in the process of pressurizing the porous metal substrate and the positive electrode mixture layer, and the porous metal substrate and the positive electrode mixture layer can be easily integrated.
  • the porosity is preferably 99.5% or less, more preferably 99% or less, and particularly preferably 98.5% or less.
  • the thickness of the portion of the porous metal substrate that is embedded in the positive electrode mixture layer is preferably 10% or more, and more preferably 20% or more, of the thickness of the porous metal substrate (the thickness of the entire porous metal substrate, including the thickness of the portion where the positive electrode mixture layer coexists; unless otherwise specified, the same applies below to the thickness of the porous metal substrate) from the viewpoint of more reliably integrating the porous metal substrate and the positive electrode mixture layer.
  • the end of the porous metal substrate opposite to the positive electrode mixture layer side is not embedded in the positive electrode mixture layer, and the end of the positive electrode (the surface of the positive electrode) is composed only of the porous metal substrate. That is, when the porous metal substrate is compressed in the thickness direction during the production of the power generating element described below, it is desirable that the pores at the end of the porous metal substrate are crushed and eliminated, and only the porous metal substrate is exposed on the surface of the positive electrode.
  • some of the pores at the end of the porous metal substrate may not be crushed and may be filled with the positive electrode mixture, and it is also acceptable that some of the positive electrode mixture may be exposed on the surface of the positive electrode together with the end of the porous metal substrate, as long as it does not significantly affect the contact resistance with the current collector.
  • Figure 5 shows a scanning electron microscope (SEM) photograph of the surface of an example of a positive electrode.
  • SEM scanning electron microscope
  • the proportion of the area of the exposed positive electrode mixture on the positive electrode surface is desirable to set the proportion of the area of the exposed positive electrode mixture on the positive electrode surface to 50% or less in a plan view, more desirably 25% or less, even more desirably 15% or less, and particularly desirably 10% or less.
  • the thickness of the porous metal substrate is preferably 1% or more, more preferably 2% or more, and particularly preferably 3% or more of the total thickness of the positive electrode mixture layer (including the thickness of the portion coexisting with the porous metal substrate.
  • the "thickness of the positive electrode mixture layer" referred to below means the “total thickness of the positive electrode mixture layer” here).
  • the thickness of the porous metal substrate is preferably 30% or less, more preferably 20% or less, and particularly preferably 10% or less of the thickness of the positive electrode mixture layer.
  • the thickness of the porous metal substrate is preferably 10 ⁇ m or more, more preferably 20 ⁇ m or more, and particularly preferably 30 ⁇ m or more, while it is preferably 300 ⁇ m or less, more preferably 200 ⁇ m or less, and particularly preferably 100 ⁇ m or less.
  • the thickness of the positive electrode mixture layer is preferably 0.2 mm or more, more preferably 0.5 mm or more, and particularly preferably 0.7 mm or more, while it is preferably 3 mm or less, more preferably 2.5 mm or less, and particularly preferably 2 mm or less.
  • the thickness of the porous metal substrate, the thickness of the positive electrode mixture layer, and the thickness of the negative electrode mixture layer described later are determined from the maximum thickness-wise width of the area in which the porous metal substrate can be confirmed and the area in which the positive electrode mixture or the negative electrode mixture can be confirmed in an image of a cross section of the positive electrode or the negative electrode in the thickness direction observed by SEM at a magnification of 50 to 1000 times.
  • the thickness of the part of the porous metal substrate embedded in the positive electrode mixture layer or the negative electrode mixture layer is determined from the maximum thickness-wise width of the part where the area in which the porous metal substrate can be confirmed overlaps with the area in which the positive electrode mixture or the area in which the negative electrode mixture can be confirmed (the values in the examples described later are determined by these methods).
  • the proportion (area ratio) of the positive electrode mixture exposed on the surface of the positive electrode and the proportion (area ratio) of the negative electrode mixture exposed on the surface of the negative electrode are determined by the ratio (A/B) of the total area of the positive electrode mixture or negative electrode mixture exposed (A) to the area of the entire positive electrode or negative electrode (B) in an image of the positive electrode or negative electrode surface observed with an SEM at a magnification of 50 to 200 times (the values in the examples described later are determined by this method).
  • the negative electrode has, for example, a negative electrode mixture layer containing a negative electrode active material and the like, and a sheet-like porous metal substrate that functions as a current collector.
  • negative electrode active materials include carbon materials such as graphite, lithium titanium oxides (lithium titanate, etc.), simple substances containing elements such as Si and Sn, compounds (oxides, etc.), and alloys thereof. Lithium metal and lithium alloys (lithium-aluminum alloy, lithium-indium alloy, etc.) can also be used as negative electrode active materials.
  • the content of the negative electrode active material in the negative electrode mixture is preferably 40 to 80 mass % in order to increase the energy density of the battery.
  • the negative electrode mixture may contain a conductive additive. Specific examples include the same conductive additives as those exemplified above as those that may be contained in the positive electrode mixture.
  • the content of the conductive additive in the negative electrode mixture is preferably 10 to 30 parts by mass when the content of the negative electrode active material is 100 parts by mass.
  • the negative electrode mixture may contain a binder.
  • a binder Specific examples include the same binders as those exemplified above as those that may be contained in the positive electrode mixture. Note that, for example, in the case where the negative electrode mixture contains a sulfide-based solid electrolyte (described later), if good moldability can be ensured in forming the negative electrode mixture layer without using a binder, the negative electrode mixture may not need to contain a binder.
  • the negative electrode mixture requires a binder, its content is preferably 15% by mass or less, and more preferably 0.5% by mass or more. On the other hand, if the negative electrode mixture can obtain moldability without requiring a binder, its content is preferably 0.5% by mass or less, more preferably 0.3% by mass or less, and even more preferably 0% by mass (i.e., no binder is contained).
  • a solid electrolyte in the negative electrode mixture.
  • Specific examples include the same solid electrolytes as those exemplified above as those that can be included in the positive electrode mixture.
  • a sulfide-based solid electrolyte because it has high lithium ion conductivity and also has the function of increasing the moldability of the negative electrode mixture.
  • the average particle size of the solid electrolyte in the negative electrode mixture is preferably 0.1 ⁇ m or more, more preferably 0.2 ⁇ m or more, and is preferably 10 ⁇ m or less, more preferably 5 ⁇ m or less.
  • the content of the solid electrolyte in the negative electrode mixture is preferably 30 parts by mass or more, and more preferably 35 parts by mass or more, when the content of the negative electrode active material is 100 parts by mass.
  • the content of solid electrolyte in the negative electrode mixture is preferably 130 parts by mass or less, and more preferably 110 parts by mass or less, when the content of the negative electrode active material is 100 parts by mass.
  • a foamed metal porous body for the sheet-like porous metal substrate in the negative electrode.
  • An example of a foamed metal porous body is "Celmet (registered trademark)" by Sumitomo Electric Industries, Ltd.
  • such a porous metal substrate usually has a thickness before use in the negative electrode (power generating element) that is greater than the thickness described above (thickness within the negative electrode) (for example, the thickness before compression is preferably 0.1 mm or more, more preferably 0.3 mm or more, and particularly preferably 0.5 mm or more, while preferably 3 mm or less, more preferably 2 mm or less, and particularly preferably 1.5 mm or less).
  • the thickness is compressed in the thickness direction to the value described below.
  • the porosity of the porous metal substrate before compression is preferably 80% or more, more preferably 90% or more, and particularly preferably 95% or more, so that the pores of the porous metal substrate can be easily filled with the negative electrode mixture in the process of pressurizing the porous metal substrate and the negative electrode mixture layer, and so that the porous metal substrate and the negative electrode mixture layer can be easily integrated.
  • the porosity is preferably 99.5% or less, more preferably 99% or less, and particularly preferably 98.5% or less.
  • the thickness of the portion of the porous metal substrate that is embedded in the negative electrode mixture layer is preferably 10% or more, and more preferably 20% or more, of the thickness of the porous metal substrate (the thickness of the entire porous metal substrate, including the thickness of the portion where the negative electrode mixture layer coexists; unless otherwise specified, the same applies below to the thickness of the porous metal substrate) from the viewpoint of more reliably integrating the porous metal substrate and the negative electrode mixture layer.
  • the end of the porous metal substrate opposite to the negative electrode mixture layer side is not embedded in the negative electrode mixture layer, and the end of the negative electrode (the surface of the negative electrode) is composed only of the porous metal substrate. That is, when the porous metal substrate is compressed in the thickness direction during the production of the power generating element described below, it is desirable that the pores at the end of the porous metal substrate are crushed and eliminated, and only the porous metal substrate is exposed on the surface of the negative electrode.
  • some of the pores at the end of the porous metal substrate may not be crushed and may be filled with the negative electrode mixture, and it is also acceptable that some of the negative electrode mixture may be exposed on the surface of the negative electrode together with the end of the porous metal substrate, as long as it does not significantly affect the contact resistance with the current collector.
  • the proportion of the area of the exposed negative electrode mixture on the negative electrode surface is desirable to set the proportion of the area of the exposed negative electrode mixture on the negative electrode surface to 50% or less in a plan view, more desirably 25% or less, even more desirably 15% or less, and particularly desirably 10% or less.
  • the thickness of the porous metal substrate is preferably 1% or more, more preferably 2% or more, and particularly preferably 3% or more of the total thickness of the negative electrode mixture layer (including the thickness of the portion coexisting with the porous metal substrate.
  • the "thickness of the negative electrode mixture layer" referred to below means the “total thickness of the negative electrode mixture layer” here).
  • the thickness of the porous metal substrate is preferably 30% or less, more preferably 20% or less, and particularly preferably 10% or less of the thickness of the negative electrode mixture layer.
  • the thickness of the porous metal substrate is preferably 10 ⁇ m or more, more preferably 20 ⁇ m or more, and particularly preferably 30 ⁇ m or more, while it is preferably 300 ⁇ m or less, more preferably 200 ⁇ m or less, and particularly preferably 100 ⁇ m or less.
  • the thickness of the negative electrode mixture layer is preferably 0.2 mm or more, more preferably 0.5 mm or more, and particularly preferably 0.7 mm or more, while it is preferably 4 mm or less, more preferably 3.5 mm or less, and particularly preferably 3 mm or less.
  • Solid electrolyte layer In the power generating element, a solid electrolyte layer is interposed between the positive electrode and the negative electrode.
  • Specific examples of the solid electrolyte constituting the solid electrolyte layer include the same solid electrolytes as those exemplified above as those that can be contained in the positive electrode mixture.
  • a sulfide-based solid electrolyte because it has high lithium ion conductivity and has a function of improving moldability, and it is more preferable to use a sulfide-based solid electrolyte having an argyrodite-type crystal structure, and it is even more preferable to use one represented by the general composition formula (1), the general composition formula (2), or the general composition formula (3).
  • the solid electrolyte layer may have a porous body such as a resin nonwoven fabric as a support.
  • the thickness of the solid electrolyte is preferably 10 to 200 ⁇ m.
  • the shape of the power generating element in a plan view is not particularly limited and may be any of a circle, an ellipse, a rectangle, a hexagon, or other polygon, but is usually a circle or a rectangle.
  • a power generation element is used that is composed only of a unit laminate electrode body in which one positive electrode and one negative electrode are laminated with one solid electrolyte layer in between, and in the second embodiment of the all-solid-state battery, a power generation element is used that is composed of multiple (2, 3, 4, etc.) laminated unit electrode bodies.
  • the number of unit laminated electrode bodies in the power generation element used in the second embodiment of the all-solid-state battery is not particularly limited, and may be 10, 20 or more (usually up to about 15).
  • the unit laminated electrode bodies may be connected in parallel by electrically connecting the positive electrodes of the unit laminated electrode bodies to each other by a lead or the like and electrically connecting the negative electrodes of the unit laminated electrode bodies to each other by a lead or the like, or adjacent unit laminated electrode bodies may be connected in series by stacking them via a metal foil or the like that serves as a current collector so that electrodes of different polarities face each other.
  • one of the outermost electrodes of the power generation element is a positive electrode and the other is a negative electrode.
  • the power generation element (unit laminate electrode body) can be manufactured by a manufacturing method including, for example, a step of press-molding a powdered positive electrode mixture to form the positive electrode mixture layer, a step of press-molding a powdered solid electrolyte to form a solid electrolyte layer, and a step of press-molding a powdered negative electrode mixture to form the negative electrode mixture layer.
  • a more specific example of a method for manufacturing a power generating element (unit laminate electrode body) is a manufacturing method having the following first to third steps.
  • the powdered electrode mixture (positive electrode mixture or negative electrode mixture) is poured into a mold and pressure molded.
  • the surface pressure for pressure molding in the first step is preferably, for example, 30 to 500 MPa.
  • a porous metal substrate is placed on the electrode mixture formed by pressure molding in the first step, and then in the third step, the electrode mixture and the porous metal substrate are pressurized.
  • the pressure in this third step embeds the porous metal substrate in the electrode mixture from the end on the electrode mixture side, further compressing the electrode mixture, and compressing the porous metal substrate in the thickness direction, integrating the electrode mixture layer (positive electrode mixture layer or negative electrode mixture layer) with the porous metal substrate to form an electrode (positive electrode or negative electrode).
  • the porous metal substrate is compressed in the thickness direction, and the degree of compression is preferably such that the thickness of the porous metal substrate after compression is 30% or less of the thickness before compression, more preferably 20% or less, and particularly preferably 10% or less, from the viewpoint of ensuring a more secure bond between the porous metal substrate and the electrode mixture layer.
  • the thickness of the porous metal substrate after compression in the third step is preferably 1% or more of the thickness before compression, and more preferably 2% or more.
  • the surface pressure during the third step is preferably 800 MPa or more, more preferably 1000 MPa or more, and particularly preferably 1200 MPa or more, in order to compress and mold the electrode mixture and sufficiently increase the density of the electrode mixture layer.
  • the upper limit is usually around 2000 MPa.
  • an electrode positive or negative electrode
  • at least a portion of the porous metal substrate including the end portion on the electrode mixture layer side (a certain range in the thickness direction from the end portion of the porous metal substrate), is embedded in the surface layer of the electrode mixture layer and is integrated with the electrode mixture layer, and the other end portion of the porous metal substrate is exposed on the surface of the electrode.
  • the positive and negative electrodes are produced through the first, second and third steps described above, and are then arranged on both sides of the solid electrolyte layer, and if necessary, pressurized to form a unit laminate electrode body.
  • a preliminary step is performed in which powdered solid electrolyte is poured into a mold and pressure-molded, and an electrode mixture (positive electrode mixture or negative electrode mixture) is placed on the solid electrolyte pressure-molded in this preliminary step. Then, the first, second, and third steps are performed in sequence to produce an integrated product of the solid electrolyte layer and the electrode (positive electrode or negative electrode), which can be used as a unit laminate electrode body.
  • the surface pressure during pressure molding in the preliminary process is preferably, for example, 30 to 120 MPa.
  • a unit laminate electrode body can be manufactured by forming one of the positive and negative electrodes on one side of a solid electrolyte layer through a preliminary process, followed by the first, second and third processes, and then sequentially carrying out the first, second and third processes on the other side of the solid electrolyte layer to form the other electrode (negative or positive electrode).
  • the unit laminate electrode body manufactured as described above can be used as a power generation element.
  • a power generation element can be used in which a plurality of unit laminate electrode bodies manufactured as described above are laminated and the unit laminate electrode bodies are connected directly or in parallel by the method described above.
  • Fig. 6 is a perspective view showing a schematic diagram of an example of an all-solid-state battery.
  • each power generating element 110 and a part of a lower base material and a connection terminal 190 constituting an exterior body 150 are shown by dotted lines in order to explain the arrangement of the power generating elements 110 inside the all-solid-state battery 101.
  • a total of 25 power generating elements 110 having a rectangular shape in a plan view are arranged in 5 columns by 5 columns inside the exterior body 150.
  • multiple power generating elements can be arranged in a single linear row, or as shown in Figure 6, they can be arranged in multiple rows vertically and horizontally, in a single circular row, or in multiple concentric rows.
  • the number of power generating elements to be placed in an all-solid-state battery so long as there is more than one, i.e., two or more, and this can be selected appropriately depending on the characteristics required when the battery is used; for example, it is possible to have 10, 100, 1000, or more.
  • ⁇ Current collector and exterior body> For the current collectors connecting the positive electrodes and negative electrodes of the multiple power generation elements, metal foils (plates), wires, etc., such as stainless steel, nickel, aluminum, iron, copper, clad materials combining these, and materials plated with nickel, chromium, nickel chromium, etc., can be used.
  • the current collectors When the all-solid-state battery is deformed due to the application of external force, the current collectors may be damaged, and the electrical connections between the positive electrodes and the negative electrodes of the multiple power generation elements may be impaired. From the viewpoint of suppressing the deterioration of the battery characteristics due to this, it is preferable to configure the current collectors with metal foils (plates).
  • the thickness of the current collector made of metal foil (plate) is preferably 10 to 300 ⁇ m.
  • a substrate having an insulating layer and a conductive layer may be used, and the conductive layer may function as a current collector that connects the positive electrodes and negative electrodes of multiple power generating elements.
  • the insulating layer in the substrate having an insulating layer and a conductive layer can be an insulating sheet (a film with substantially no pores, a woven fabric, a nonwoven fabric, etc.).
  • the material of the insulating layer can be nylon (nylon 66, etc.), polyester (polyethylene terephthalate (PET), etc.), polyolefin (polypropylene, polyethylene, etc.), polyurethane, epoxy, polyimide, and other resins.
  • the thickness of the insulating layer is preferably 1 to 100 ⁇ m.
  • the conductive layer in the substrate having an insulating layer and a conductive layer can be a metal foil that can be used for the current collector.
  • the thickness of the conductive layer is preferably 10 to 1000 ⁇ m.
  • the insulating layer and the conductive layer may simply be stacked on top of each other, but it is preferable that the insulating layer and the conductive layer are bonded together.
  • the porous metal substrate and the current collector connecting the positive electrodes may simply be in contact with each other, or may be welded to each other.
  • the porous metal substrate and the current collector connecting the negative electrodes may simply be in contact with each other, or may be welded to each other.
  • exterior body of the all-solid-state battery there are no particular limitations on the exterior body of the all-solid-state battery, and exterior bodies that have been conventionally used for all-solid-state batteries, such as metal battery containers (such as battery containers having a sealing can and an exterior can), ceramic battery containers, those made of resin films, and those made of laminate films with a metal layer on the surface of a resin film, can be used.
  • metal battery containers such as battery containers having a sealing can and an exterior can
  • ceramic battery containers those made of resin films, and those made of laminate films with a metal layer on the surface of a resin film
  • the resin film can be the same as a film that is substantially free of pores, among resin sheet-like materials that can be used as an insulating layer in a substrate having an insulating layer and a conductive layer.
  • the laminate film that constitutes the exterior body can be the same as the substrate having an insulating layer and a conductive layer.
  • the exterior body can also be constructed from a base material having an insulating layer and a conductive layer.
  • the outer edges of two base materials on which the power generating elements are arranged can be sealed by bonding or the like to form the exterior body.
  • the substrates to be bonded together to form the exterior body can be heat-sealed via an ionomer resin or the like.
  • the ionomer resin that can be used is "Himilan (ethylene-based ionomer resin, product name)" manufactured by Dow Mitsui Polychemicals.
  • the shape of the exterior body when viewed from above can be polygonal, such as a square, or circular.
  • connection terminals for connecting the all-solid-state battery to the applicable device metal plates such as stainless steel, nickel, aluminum, iron, copper, clad materials combining these, and materials plated with nickel, chrome, nickel chrome, etc. can be used.
  • the thickness of the connection terminals is preferably 50 to 300 ⁇ m.
  • insulating material constituting the frame examples include polyolefins such as polypropylene, polyesters such as PET, and nylons such as nylon 66.
  • the thickness of the frame there are no particular restrictions on the thickness of the frame as long as it effectively prevents contact between adjacent generating elements, but it is usually preferable for it to be 30 to 100% of the thickness of the generating elements.
  • the shape and size of the opening there are no particular restrictions on the shape and size of the opening as long as it allows the generating elements to be inserted and prevents contact between adjacent generating elements.
  • insulators to be placed in areas where the power generating elements are not placed include ionomer resins (e.g., the same as those exemplified above for bonding substrates to form the outer casing), polyolefins (polypropylene, polyethylene, etc.), polyurethane, epoxy, polyimide, and other resins.
  • the insulating layer provided on at least a part of the side surface of the power generating element can be formed, for example, by covering the side surface of the power generating element with the same insulating material as exemplified above as a material that can form the frame.
  • Examples of methods for covering the side surface of the power generating element with an insulating material include a method of covering the side surface of the power generating element with an insulating material that has been heated or otherwise rendered fluid, and then solidifying the material, and a method of covering the side surface of the power generating element with a film made of an insulating material.
  • the thickness of the insulating layer covering the side surface of the power generating element should be sufficient to effectively prevent contact between adjacent power generating elements, but is usually preferably 1 to 100 ⁇ m.
  • Example 1 A negative electrode mixture was prepared by mixing lithium titanate (Li4Ti5O12, negative electrode active material) having an average particle size of 2 ⁇ m, a sulfide-based solid electrolyte (Li6PS5Cl ) having an average particle size of 0.7 ⁇ m, and graphene (conductive additive) in a mass ratio of 50:41:9.
  • lithium titanate Li4Ti5O12, negative electrode active material
  • Li6PS5Cl sulfide-based solid electrolyte
  • graphene conductive additive
  • LiCoO 2 positive electrode active material
  • LiNbO 3 coating layer formed on its surface LiNbO 3
  • Si 6 PS 5 Cl sulfide-based solid electrolyte having an average particle size of 0.7 ⁇ m
  • graphene were mixed in a mass ratio of 65:30.7:4.3 to prepare a positive electrode mixture.
  • a powder of sulfide-based solid electrolyte ( Li6PS5Cl ) having an average particle size of 0.7 ⁇ m was placed in a powder molding die, and pressure molding was performed at a surface pressure of 70 MPa using a press machine to form a provisionally molded layer of the solid electrolyte layer.
  • the negative electrode mixture was placed on the upper surface of the provisionally molded layer of the solid electrolyte layer and pressure molding was performed at a surface pressure of 50 MPa, and a provisionally molded layer of the negative electrode was further formed on the provisionally molded layer of the solid electrolyte layer.
  • a nickel-made porous metal foam (nickel "Celmet” (registered trademark)) made by Sumitomo Electric Industries, Ltd., cut into a 10 mm x 10 mm square (thickness: 1.2 mm, porosity: 98%) was placed on the provisionally molded layer of the negative electrode formed on the provisionally molded layer of the solid electrolyte layer, and pressure molding was performed with a surface pressure of 300 MPa to form an integrated body of the solid electrolyte layer and the negative electrode.
  • nickel "Celmet” registered trademark
  • the positive electrode mixture was placed on the upper surface of the solid electrolyte layer in the mold (the surface opposite to the surface having the negative electrode) and pressure molding was performed with a surface pressure of 50 MPa, forming a preformed layer for the positive electrode on the solid electrolyte layer.
  • the thickness of the negative electrode mixture layer of the negative electrode, the thickness of the porous metal substrate, and the thickness of the portion of the porous metal substrate embedded in the negative electrode mixture layer were 1,850 ⁇ m, 50 ⁇ m (4% of the thickness of the porous metal substrate before use in the negative electrode), and 10 ⁇ m (20% of the total thickness of the porous metal substrate), respectively.
  • the area ratio of the portion of the negative electrode mixture exposed on the surface of the negative electrode was 7%.
  • the thickness of the positive electrode mixture layer of the positive electrode, the thickness of the porous metal substrate, and the thickness of the portion of the porous metal substrate embedded in the positive electrode mixture layer were 1050 ⁇ m and 50 ⁇ m (4% of the thickness of the porous metal substrate before use in the positive electrode), and 10 ⁇ m (20% of the total thickness of the porous metal substrate), respectively.
  • the area ratio of the portion of the positive electrode mixture exposed on the surface of the positive electrode was 7%.
  • a polypropylene frame was prepared, measuring 56 mm long and 45 mm wide and 1.0 mm thick, with 10 mm long and 10 mm wide openings spaced 1 mm apart in 5 rows and 4 rows, and 20 generating elements obtained as described above were placed in the openings of the frame.
  • connection terminal (0.1 mm thick, 5 mm x 30 mm) was attached to each of the vertical ends.
  • a 0.1 mm thick ionomer resin (HiMilan (product name) manufactured by Dow Mitsui Polychemicals) was placed in the area where the connection terminal overlapped with the outer periphery of the laminate film described below.
  • one of the current collectors was placed on the negative electrode side of the power generating elements arranged in the frame as described above, and the porous metal substrate on the negative electrode side of each power generating element and the current collector were welded and fixed by resistance welding.
  • one of the current collectors was placed on the positive electrode side of the power generating elements, and the porous metal substrate on the positive electrode side of each power generating element and the current collector were welded and fixed by resistance welding.
  • Example 2 Power generating elements (S/t was 133) produced in the same manner as in Example 1 except that the amount of the negative electrode mixture and the amount of the positive electrode mixture were changed to obtain a negative electrode mixture layer thickness of 350 ⁇ m, a positive electrode mixture layer thickness of 200 ⁇ m, and a thickness t of 0.75 mm were arranged in 10 columns and 10 columns, and an all-solid-state battery was produced in the same manner as in Example 1 except that the thickness and size of the frame, and the sizes of the nickel plate and laminate film were changed.
  • Example 3 Power generating elements (S/t was 18) produced in the same manner as in Example 1 except that the amount of the negative electrode mixture and the amount of the positive electrode mixture were changed to obtain a negative electrode mixture layer thickness of 3500 ⁇ m, a positive electrode mixture layer thickness of 2000 ⁇ m, and a thickness t of 5.7 mm were arranged in 5 vertical rows and 2 horizontal rows, and an all-solid-state battery was produced in the same manner as in Example 1 except that the thickness and size of the frame, and the sizes of the nickel plate and laminate film were changed.
  • Example 4 A power generating element (S/t was 158) prepared in the same manner as in Example 1 was arranged in 4 columns and 2 columns, except that the amount of the negative electrode mixture and the amount of the positive electrode mixture were changed so that the thickness of the negative electrode mixture layer was 3500 ⁇ m, the thickness of the positive electrode mixture layer was 2000 ⁇ m, the shape was a rectangle of 30 mm ⁇ 30 mm in plan view (area S was 900 mm2), and the thickness t was 5.7 mm.
  • An all-solid-state battery was prepared in the same manner as in Example 1, except that the thickness and size of the frame, and the sizes of the nickel plate and laminate film were changed.
  • Example 5 A power generating element (S/t was 290) prepared in the same manner as in Example 1 except for changing the amount of the negative electrode mixture and the amount of the positive electrode mixture and making the shape a 30 mm x 30 mm rectangle in a plan view (area S was 900 mm2) was arranged in 5 columns and 3 columns, and an all-solid-state battery was prepared in the same manner as in Example 1 except for changing the sizes of the frame, nickel plate, and laminate film.
  • S/t was 290
  • Power generating elements (S/t was 13) produced in the same manner as in Example 1 except that the amount of the negative electrode mixture and the amount of the positive electrode mixture were changed to obtain a negative electrode mixture layer thickness of 4700 ⁇ m, a positive electrode mixture layer thickness of 2700 ⁇ m, and a thickness t of 7.6 mm were arranged in 10 columns and 5 columns, and an all-solid-state battery was produced in the same manner as in Example 1 except that the thickness and size of the frame, and the sizes of the nickel plate and laminate film were changed.
  • a power generating element (S/t was 281) prepared in the same manner as in Example 1 was arranged in 2 vertical rows and 2 horizontal rows, except that the amount of the negative electrode mixture and the amount of the positive electrode mixture were changed so that the negative electrode mixture layer had a thickness of 3500 ⁇ m, the positive electrode mixture layer had a thickness of 2000 ⁇ m, and the shape was a rectangle of 40 mm ⁇ 40 mm in plan view (area S was 1600 mm 2 ), and the thickness t was 5.7 mm.
  • An all-solid-state battery was prepared in the same manner as in Example 1, except that the thickness and size of the frame, and the sizes of the nickel plate and laminate film were changed.
  • Example 3 A power generating element (S/t was 516) prepared in the same manner as in Example 1 except for changing the amount of the negative electrode mixture and the amount of the positive electrode mixture and making the element a 40 mm x 40 mm square in a planar view (area S was 1600 mm2) was arranged in 4 columns and 2 columns, and an all-solid-state battery was prepared in the same manner as in Example 1 except for changing the sizes of the frame, nickel plate, and laminate film.
  • This charge-discharge operation was counted as one cycle, and after repeating this cycle 300 times, the 0.2 C capacity was measured in the same manner as described above, and the ratio of the 0.2 C discharge capacity before the cycles to the 0.2 C discharge capacity after 300 cycles (i.e., the capacity retention rate before and after the cycles) was expressed as a percentage to be used as the charge-discharge cycle characteristic of each all-solid-state battery.
  • the all-solid-state batteries of Examples 1 to 5 which have multiple power generating elements with appropriate values for thickness t and area S, had a high positive electrode utilization rate at 0.2 C discharge (i.e., the 0.2 C discharge capacity was close to the theoretical value), and also had excellent 2 C load characteristics and charge/discharge cycle characteristics.
  • the all-solid-state batteries of Comparative Examples 1 to 3 which have multiple power generating elements with inappropriate thickness t or area S, had a low positive electrode utilization rate at 0.2 C discharge, and also had poor 2 C load characteristics and charge/discharge cycle characteristics. Furthermore, it was confirmed that cracks had occurred inside the constituent power generating elements of the all-solid-state batteries of Comparative Examples 2 and 3, which have power generating elements with large area S.
  • the all-solid-state battery of the present invention can be used in the same applications as conventionally known primary and secondary batteries, but because it has a solid electrolyte instead of an organic electrolyte, it has excellent heat resistance and can be preferably used in applications where it is exposed to high temperatures.

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Abstract

L'invention concerne une batterie tout solide ayant d'excellentes caractéristiques de décharge et une capacité élevée, ainsi qu'un procédé de production de ladite batterie tout solide. Cette batterie tout solide se rapporte aux ODD 3, 7, 11 et 12.　Cette batterie tout solide comprend une pluralité d'éléments de génération d'énergie agencés d'une certaine manière, et est caractérisée en ce que chaque élément de génération d'énergie comprend une électrode positive, une électrode négative et une couche d'électrolyte solide placée entre l'électrode positive et l'électrode négative, présente une épaisseur t (mm) de 0,5 à 6,0, et dans une vue en plan, présente une superficie S (mm2) de 10 à 1 000, et en ce que, dans la pluralité d'éléments de génération d'énergie, les électrodes positives sont directement connectées les unes aux autres par un collecteur de courant et les électrodes négatives sont directement connectées les unes aux autres par un collecteur de courant.
PCT/JP2023/032791 2022-09-28 2023-09-08 Batterie tout solide et procédé de production correspondant WO2024070579A1 (fr)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001015153A (ja) * 1999-06-29 2001-01-19 Kyocera Corp 全固体二次電池およびその製造方法
JP2015076182A (ja) * 2013-10-07 2015-04-20 古河機械金属株式会社 電気素子および電気素子の製造方法
JP2015092433A (ja) * 2012-02-24 2015-05-14 住友電気工業株式会社 全固体リチウム二次電池
JP2018133200A (ja) * 2017-02-15 2018-08-23 パナソニックＩｐマネジメント株式会社 全固体電池、蓄電装置、および全固体電池のリユース方法
JP2020161492A (ja) * 2015-04-27 2020-10-01 パナソニックＩｐマネジメント株式会社 電池
JP2022110671A (ja) * 2021-01-19 2022-07-29 本田技研工業株式会社 コイン型全固体電池及びその製造方法

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001015153A (ja) * 1999-06-29 2001-01-19 Kyocera Corp 全固体二次電池およびその製造方法
JP2015092433A (ja) * 2012-02-24 2015-05-14 住友電気工業株式会社 全固体リチウム二次電池
JP2015076182A (ja) * 2013-10-07 2015-04-20 古河機械金属株式会社 電気素子および電気素子の製造方法
JP2020161492A (ja) * 2015-04-27 2020-10-01 パナソニックＩｐマネジメント株式会社 電池
JP2018133200A (ja) * 2017-02-15 2018-08-23 パナソニックＩｐマネジメント株式会社 全固体電池、蓄電装置、および全固体電池のリユース方法
JP2022110671A (ja) * 2021-01-19 2022-07-29 本田技研工業株式会社 コイン型全固体電池及びその製造方法

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