All-solid-state battery, and method for manufacturing all-solid-state battery

Abstract

An all-solid-state battery 1 comprises: a battery molded body 20 including a positive electrode 201, a negative electrode 202, and a solid electrolyte layer 203; a bottomed cylindrical battery can 10 accommodating a cell assembly 21 that includes a positive electrode power supply plate 30 connected to the positive electrode 201 of the battery molded body 20 and a negative electrode power supply plate 40 connected to the negative electrode 202 of the battery molded body 20; and a can lid part 50 sealing an opening at one end of the battery can 10. The can lid part 50 has a conductive electrode terminal 52 and an insulation part 53 provided around the electrode terminal 52. The battery molded body 20 and the insulation part 53 are arranged along an axis X1 direction intersecting a bottom surface 101 of the battery can 10. A compression direction of the battery molded body 20 and the insulation part 53 is toward the bottom surface 101 of the battery can 10 along the axis X1 direction.

Description

All-solid-state battery and method for manufacturing the same

[0001] The present disclosure relates to an all-solid-state battery and a method for manufacturing an all-solid-state battery.

[0002] Lithium secondary batteries, particularly lithium ion secondary batteries, have traditionally been used in portable electronic devices such as mobile phones and laptop computers, and electric vehicles. Lithium ion batteries contain a flammable organic solvent as a non-aqueous electrolyte. With the development of the above-mentioned devices and electric vehicles, the energy density of lithium ion secondary batteries has increased, and the amount of flammable organic solvent has tended to increase. As a result, even greater reliability is required of lithium ion secondary batteries.

[0003] In this situation, all-solid-state lithium secondary batteries (all-solid-state secondary batteries) that do not use organic solvents have attracted attention. All-solid-state secondary batteries use a molded body of a solid electrolyte that does not use organic solvents, instead of conventional organic solvent-based electrolytes. All-solid-state secondary batteries are configured as a laminate in which a positive electrode layer, a negative electrode layer, and a solid electrolyte layer are stacked.

[0004] Patent Document 1 discloses a battery in which a laminate is housed in a space formed by a housing and a lid.

[0005] Japanese Patent Application Laid-Open No. 2004-253287

[0006] The laminate is formed by compressing solid (powder) materials, but its strength decreases due to expansion in high-temperature environments and contraction in low-temperature environments, and it may be damaged by impact, etc. On the other hand, there is a demand for all-solid-state batteries that can be used in high-temperature and low-temperature environments.

[0007] A brief summary of a representative embodiment of the present invention will be given below.

[0008] An all-solid-state battery according to one embodiment includes a battery molded body having a positive electrode, a negative electrode, and a solid electrolyte layer interposed between the positive electrode and the negative electrode, a positive electrode power supply plate connected to the positive electrode of the battery molded body, and a negative electrode power supply plate connected to the negative electrode of the battery molded body. The battery can has a bottomed cylindrical shape and a can lid that seals an opening at one end of the battery can. The can lid has a conductive electrode terminal electrically connected to the positive electrode power supply plate or the negative electrode power supply plate, and an insulating portion provided around the electrode terminal. The battery molded body and the insulating portion are arranged along an axial direction that intersects with a bottom surface of the battery can. The battery molded body and the insulating portion are compressed in a direction toward the bottom surface of the battery can, which is along the axial direction.

[0009] A method for manufacturing an all-solid-state battery according to one embodiment includes a first step of compressing a positive electrode mixture, a negative electrode mixture, and a solid electrolyte in a first compression direction to form a laminate in which a positive electrode, a negative electrode, and a solid electrolyte layer interposed between the positive electrode and the negative electrode are laminated, producing a positive electrode tab connected to the positive electrode and a negative electrode tab connected to the negative electrode, attaching the positive electrode tab to the positive electrode of the laminate, and attaching the negative electrode tab to the negative electrode of the laminate to manufacture a battery molded body; The method includes a second step of manufacturing a cell assembly by attaching a positive electrode power supply plate and a negative electrode power supply plate to the negative electrode tab; a third step of accommodating the cell assembly in a bottomed cylindrical battery can with the first compression direction aligned in an axial direction intersecting the bottom surface of the battery can; a fourth step of compressing an insulating material in the second compression direction to form an insulating portion and integrally forming a can lid portion having the insulating portion and an electrode terminal made of a conductive material; and a fifth step of attaching the can lid portion to one end of the battery can with the second compression direction aligned in the axial direction.

[0010] According to one embodiment, it is possible to provide an all-solid-state battery that can be used in high-temperature and low-temperature environments.

[0011] 1 is a perspective view of the appearance of an all-solid-state battery according to an embodiment; FIG. 2 is a cross-sectional view of the all-solid-state battery taken along line A-A in FIG. 1; FIG. 3 is an exploded perspective view of a cell assembly; FIG. 4 is a perspective view of the appearance of a battery molded body; FIG. 5 is a perspective view of the appearance of a holder; FIG. 6 is a perspective view of the appearance of a can lid; FIG. 7 is a diagram illustrating a connection power supply plate; FIG. 8 is a flowchart illustrating the manufacturing direction of an all-solid-state battery; FIG. 9 is a schematic diagram illustrating a method for forming a laminate; FIG. 10 is a schematic diagram illustrating a laminate; FIG. 11 is a diagram illustrating a manufacturing process of a battery molded body; FIG. 12 is a diagram illustrating a manufacturing process of a cell assembly; FIG. 13 is a diagram illustrating a manufacturing process of a cell assembly; FIG. 14 is a diagram illustrating a manufacturing process of a cell assembly; FIG. 15 is a diagram illustrating a manufacturing process of a cell assembly; FIG. 16 is a diagram illustrating a process of housing a cell assembly in a battery can; FIG. 17 is a diagram illustrating a process of housing a cell assembly in a battery can; FIG. 18 is a diagram illustrating a manufacturing process of a can lid; FIG. 19 is a diagram illustrating a process of attaching the can lid to the battery can; FIG. 19 is a perspective view of the appearance of an all-solid-state battery when a cushioning member is attached to the can lid.

[0012] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, identical parts are generally designated by the same reference numerals, and repeated explanations will be omitted. In the drawings, the depiction of components may not represent their actual positions, sizes, shapes, ranges, etc., in order to facilitate understanding of the invention. <Embodiments>

[0013] An all-solid-state battery according to an embodiment of the present disclosure will be described below with reference to the drawings. FIG. 1 is a perspective view of the appearance of an all-solid-state battery 1 according to the embodiment. FIG. 2 is a cross-sectional view of the all-solid-state battery 1 taken along line A-A in FIG. 1. Note that, although the term "all-solid-state battery" is used in the following description of the embodiment, it is also possible to use terms such as a stacked solid-state battery or a battery module instead.

[0014] The all-solid-state battery 1 includes a battery can 10, a cell assembly 21, a can lid 50, and a connection power supply plate 60. The cell assembly 21 is housed inside the battery can 10, and includes a battery molded body 20, a holder 22, a positive electrode power supply plate 30, and a negative electrode power supply plate 40. The holder 22 also includes a support portion.

[0015] <Battery Can 10> The battery can 10 has a cylindrical shape with one open end and the other closed. Specifically, as shown in the figure, the battery can 10 is a cylindrical can formed into a bottomed cylindrical shape. The battery can 10 contains a battery molded body 20, a positive electrode power supply plate 30, and a negative electrode power supply plate 40, which will be described in detail later.

[0016] The battery can 10 is not limited to a cylindrical can, but may be a square can with a rectangular cross section or the like, depending on the shape of the battery molded body 20 housed therein.

[0017] The battery can 10 has a bottom surface 101 and a side surface 102. The side surface 102 is connected to the bottom surface 101 and extends in a direction intersecting the bottom surface 101, in a height direction or a width direction depending on how it is placed, or more specifically in a direction perpendicular to the bottom surface 101.

[0018] Hereinafter, the description will be given assuming that an axis X1 passes through the center of the bottom surface 101 and extends in a direction perpendicular to the bottom surface 101. The bottom surface 101 side of the battery can 10 along the axis X1 may be referred to as the bottom, and the leading end side (i.e., the side of the battery can 10 away from the bottom surface 101) may be referred to as the top. The top may also be referred to as one side of the battery can 10, and the bottom may also be referred to as the other side of the battery can 10.

[0019] The battery can 10 is formed of a conductive material, for example, a metal material such as aluminum, stainless steel, a nickel alloy, etc. When the battery can 10 is electrically connected to the negative electrode or positive electrode described below, the material of the battery can 10 is preferably selected so as to prevent corrosion of the battery can 10 or deterioration of the material due to alloying with lithium ions.

[0020] A plurality of recesses 104 extending upward from the lower end along the axis X1 are formed by, for example, pressing on the outer peripheral wall surface of the side surface 102 of the battery can 10. This increases the rigidity of the battery can 10 and prevents the battery can 10 from being easily crushed or damaged when a strong external force acts on the battery can 10.

[0021] By forming the recess 104, a protrusion that protrudes toward the inside of the battery can 10 is formed on the inner peripheral wall surface of the side surface 102 of the battery can 10 at the position where the recess 104 is formed. This protrusion comes into contact with the side surface of the battery molded body 20 when the battery molded body 20 (described later) is housed inside the battery can 10. This suppresses the battery molded body 20 from vibrating inside the battery can 10.

[0022] The recess 104 does not have to be formed on the outer peripheral wall surface of the side surface 102 of the battery can 10. In this case, the battery molded body 20 and the inner peripheral wall surface of the side surface 102 of the battery can 10 may be fixed by adhesive. Alternatively, a sealing member made of a non-conductive material such as a resin material may be disposed in the gap between the battery molded body 20 and the inner peripheral wall surface of the side surface 102 of the battery can 10 to fill the gap.

[0023] <Cell assembly 21> The cell assembly 21 is housed in the battery can 10 via a buffer sheet 105, which is an insulating soft elastic material such as silicone rubber, between the cell assembly 21 and the bottom surface 101 of the battery can 10. The buffer sheet 105 does not necessarily have to be provided.

[0024] As described above, the cell assembly 21 includes a battery molded body 20, a holder 22, a positive electrode power supply plate 30, and a negative electrode power supply plate 40. As shown in FIG. 2 , the cell assembly 21 of this embodiment includes six battery molded bodies 20 (20a, 20b, 20c, 20d, 20e, and 20f). The number of battery molded bodies 20 is not limited to six, and may be more or less than six. In the following description, each individual battery molded body 20 may be referred to as a cell.

[0025] 3 is an exploded perspective view of the cell assembly 21. In the cell assembly 21, battery molded bodies 20 (20a, 20b, 20c, 20d, 20e, 20f) that are multiple cells and insulating plates 210 (210a, 210b, 210c, 210d, 210e) are stacked along the axis X1. That is, in the cell assembly 21, the multiple battery molded bodies 20 are arranged along the axis X1. This allows the multiple battery molded bodies 20 to be accommodated in the cylindrical battery can 10, thereby preventing the all-solid-state battery 1 from becoming too large.

[0026] The stacked battery molded bodies 20 are held from below, the sides, and above by holders 22. The positive electrode tabs 206 of each of the battery molded bodies 20 are connected to the positive electrode power supply plate 30. The negative electrode tabs 207 of each of the battery molded bodies 20 are connected to the negative electrode power supply plate 40.

[0027] The sides of the cell assembly 21 are covered with non-conductive heat-shrink tubing 213 made of a high molecular weight polymer, such as polyethylene or various elastomers. That is, the multiple battery molded bodies 20, the holder 22, the positive power supply plate 30, and the negative power supply plate 40 are covered with the heat-shrink tubing 213. However, the second holding portion 24 (described later) of the holder 22, which is disposed on the uppermost surface of the cell assembly 21, is not covered with the heat-shrink tubing 213. Furthermore, the vicinity of the upper end of the positive power supply plate 30 and the vicinity of the upper end of the negative power supply plate 40 are not covered with the heat-shrink tubing 213.

[0028] <Battery Molded Body 20> Each battery molded body 20 is a laminated body 211 in which a molded body (layer) of a positive electrode 201, a molded body (layer) of a negative electrode 202, and a solid electrolyte layer 203 are stacked. Specifically, in the battery molded body 20, the solid electrolyte layer 203 is stacked between the positive electrode 201 and the negative electrode 202. Note that FIGS. 2 and 3 show a case in which the battery molded body 20 is molded into a cylindrical shape. However, the shape of the battery molded body 20 is not limited to a cylindrical shape, and may be a polygonal pillar shape such as a rectangular pillar.

[0029] 2, a polar sheet 201a is attached to one surface of the laminate 211, i.e., the surface on which the positive electrode 201 is formed. The polar sheet 201a is formed in a disk shape according to the shape of the cylindrical laminate 211. When the laminate 211 is prismatic, the polar sheet 201a is also formed in a polygonal plate shape according to the shape of the laminate 211.

[0030] A positive electrode tab 206 is joined to the polar sheet 201a by, for example, resistance welding. A polar sheet 202a is attached to the other surface of the laminate 211, i.e., the surface on which the negative electrode 202 is formed. A negative electrode tab 207 is joined to the polar sheet 202a by, for example, resistance welding. The polar sheet 202a is also formed into a shape corresponding to the shape of the laminate 211.

[0031] The side surfaces, part of the top surface, and part of the bottom surface of the laminate 211 are covered with a non-conductive heat-shrinkable tube 212 made of a high molecular weight polymer such as polyethylene or various elastomers.

[0032] <Positive electrode 201> The positive electrode 201 is a cylindrically shaped compact (layer) formed by compressing a positive electrode mixture by pressing it. The positive electrode 201 is not limited to a cylindrically shaped layer, and may be a prismatic layer. The positive electrode mixture is not particularly limited as long as it is, for example, a positive electrode active material used in a lithium ion secondary battery, that is, a material capable of absorbing and releasing lithium ions. Specifically, LiM ｘ Mn ２－ｘ O ４ (wherein M is at least one element selected from the group consisting of Li, B, Mg, Ca, Sr, Ba, Ti, V, Cr, Fe, Co, Ni, Cu, Al, Sn, Sb, In, Nb, Mo, W, Y, Ru, and Rh, and 0.01≦x≦0.5), a spinel-type lithium manganese composite oxide represented by Li ｘ Mn （１－ｙ－ｘ） Ni ｙ M ｚ O （２－ｋ） F ｌ (wherein M is at least one element selected from the group consisting of Co, Mg, Al, B, Ti, V, Cr, Fe, Cu, Zn, Zr, Mo, Sn, Ca, Sr, and W, and 0.8≦x≦1.2, 0<y<0.5, 0≦z≦0.5, k+l<1, −0.1≦k≦0.2, 0≦l≦0.1), a layered compound represented by １－ｘ M ｘ O ２(wherein M is at least one element selected from the group consisting of Al, Mg, Ti, Zr, Fe, Ni, Cu, Zn, Ga, Ge, Nb, Mo, Sn, Sb, and Ba, and 0≦x≦0.5), lithium cobalt composite oxide represented by LiNi １－ｘ M ｘ O ２ (wherein M is at least one element selected from the group consisting of Al, Mg, Ti, Zr, Fe, Co, Cu, Zn, Ga, Ge, Nb, Mo, Sn, Sb, and Ba, and 0≦x≦0.5), a lithium nickel composite oxide represented by LiM １－ｘ N ｘ P.O. ４ (wherein M is at least one element selected from the group consisting of Fe, Mn, and Co, and N is at least one element selected from the group consisting of Al, Mg, Ti, Zr, Ni, Cu, Zn, Ga, Ge, Nb, Mo, Sn, Sb, and Ba, and 0≦x≦0.5), Li ４ Ti ５ O １２ These may be used alone or in combination of two or more.

[0033] The average particle size of the positive electrode active material is preferably 1 μm or more, more preferably 2 μm or more, and is preferably 10 μm or less, more preferably 8 μm or less. The positive electrode active material may be primary particles or secondary particles formed by aggregation of primary particles. When a positive electrode active material having an average particle size within the above range is used, a large interface with the solid electrolyte can be secured, thereby further improving the load characteristics of the battery.

[0034] The positive electrode active material preferably has a reaction suppression layer on its surface to suppress reaction with the solid electrolyte.

[0035] If the positive electrode active material and the solid electrolyte come into direct contact within the positive electrode mixture compact, the solid electrolyte may oxidize to form a resistance layer, resulting in a decrease in ionic conductivity within the compact. By providing a reaction suppression layer on the surface of the positive electrode active material that suppresses reaction with the solid electrolyte and preventing direct contact between the positive electrode active material and the solid electrolyte, it is possible to suppress a decrease in ionic conductivity within the compact due to oxidation of the solid electrolyte.

[0036] 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. Examples of 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, LiNbO ３ Nb-containing oxides such as Li ３ P.O. ４ , Li ３ BO ３ , Li ４ SiO ４ , Li ４ GeO ４ , LiTiO ３ , LiZrO ３ The reaction suppression layer may contain only one of these oxides, or may contain two or more of them, or may contain a composite compound of two or more of these oxides. Among these oxides, it is preferable to use an Nb-containing oxide, such as LiNbO ３ It is more preferable to use

[0037] The reaction suppression layer is preferably present on the surface in an amount of 0.1 to 1.0 part by mass per 100 parts by mass of the positive electrode active material, which allows for effective suppression of the reaction between the positive electrode active material and the solid electrolyte.

[0038] Examples of methods for forming a reaction suppression layer on the surface of a positive electrode active material include the sol-gel method, mechanofusion method, CVD method, and PVD method.

[0039] The content of the positive electrode active material in the positive electrode mixture is preferably 60 to 95 mass %.

[0040] Examples of the conductive additive for the positive electrode 201 include carbon materials such as graphite (natural graphite, artificial graphite), graphene, carbon black, carbon nanofibers, and carbon nanotubes. The content of the conductive additive in the positive electrode mixture is preferably 1 to 10 mass %.

[0041] The solid electrolyte of the positive electrode 201 can be one or more of various sulfide-based solid electrolytes, hydride-based solid electrolytes, and oxide-based solid electrolytes, which will be described later as being usable for the negative electrode 202. In order to improve the battery characteristics, it is desirable to contain a sulfide-based solid electrolyte.

[0042] The content of the solid electrolyte in the positive electrode mixture is preferably 4 to 30 mass %.

[0043] The positive electrode mixture may or may not contain a resin binder. Examples of resin binders include fluororesins such as polyvinylidene fluoride (PVDF). However, since the resin binder acts as a resistance component in the positive electrode mixture, it is desirable that the amount of the resin binder be as small as possible. Therefore, it is preferable that the positive electrode mixture does not contain a resin binder, or if it does contain one, its content is 0.5 mass% or less. It is more preferable that the content of the resin binder in the positive electrode mixture is 0.3 mass% or less, and even more preferably 0 mass% (i.e., no resin binder is contained).

[0044] When a current collector is used for the positive electrode 201, the current collector may be a foil of a metal such as aluminum or stainless steel, a punched metal, a mesh, an expanded metal, a foamed metal, a carbon sheet, or the like.

[0045] The compact of the positive electrode mixture can be formed, for example, by compressing a positive electrode mixture prepared by mixing a positive electrode active material, a conductive additive, a solid electrolyte, and, if necessary, a binder, by pressure molding or the like.

[0046] In the case of a positive electrode having a current collector, it can be produced by bonding a molded body of the positive electrode mixture formed by the above-mentioned method to the current collector by, for example, pressing.

[0047] The thickness of the positive electrode mixture compact (in the case of the positive electrode 201 having a current collector, the thickness of the positive electrode mixture compact per one surface of the current collector; the same applies hereinafter) is preferably 200 μm or more from the viewpoint of increasing the capacity of the battery. The thickness of the positive electrode mixture compact is usually 2000 μm or less.

[0048] A positive electrode tab 206 is attached to the positive electrode 201. The positive electrode tab 206 is made of a metal material such as aluminum. The positive electrode tab 206 is joined to a positive electrode power supply plate 30 (described later) by welding.

[0049] <Negative Electrode 202> The negative electrode 202 is a cylindrically shaped compact (layer) formed by compressing (pressing) the negative electrode mixture. The negative electrode is not limited to a cylindrically shaped layer, but may also be a prismatic layer. The negative electrode mixture can be formed using a negative electrode active material used in lithium-ion secondary batteries. The negative electrode active material is not particularly limited as long as it is a material capable of absorbing and releasing lithium ions. Examples of the negative electrode active material include carbon-based materials capable of absorbing and releasing lithium, such as graphite, pyrolytic carbons, cokes, glassy carbons, fired organic polymer compounds, mesocarbon microbeads (MCMB), and carbon fibers; simple substances or oxides or alloys of elements capable of forming alloys with lithium, such as Si, Sn, Ge, Bi, Sb, and In; nitrides containing lithium and transition metals such as Co, Ni, Mn, Fe, Cr, Ti, and W; metallic lithium; lithium alloys such as lithium-aluminum alloys; and lithium-containing transition metal oxides such as lithium niobium oxide and lithium titanium oxide. Examples of lithium titanium oxides include those represented by the following general composition formula (1): Li[Li １／３－ａ M １ ａ Ti ５／３－ｂ M ２ ｂ ]O ４ (1) In general compositional formula (1), M １is at least one element selected from the group consisting of Na, Mg, K, Ca, Sr and Ba, and M ２ is at least one element selected from the group consisting of Al, V, Cr, Fe, Co, Ni, Zn, Ym, Zr, Nb, Mo, Ta, and W, and 0≦a<1 / 3, 0≦b≦2 / 3.

[0050] That is, in the lithium titanium oxide represented by the general composition formula (1), a part of the Li site is an element M １ However, in the general composition formula (1), the element M １ In the lithium titanium oxide represented by the general composition formula (1), Li is an element M １ Therefore, the element M １ The value a representing the ratio may be 0.

[0051] In addition, in the lithium titanium oxide represented by the general composition formula (1), the element M ２ is a component for increasing the electronic conductivity of lithium titanium oxide, and element M ２ When b, which represents the ratio of (a) to (b), satisfies 0≦b≦2 / 3, the effect of improving the electronic conductivity can be satisfactorily ensured.

[0052] The negative electrode active material may be one or more of the above-mentioned materials. For example, when lithium titanium oxide is used, a negative electrode active material other than lithium titanium oxide may be used together with the lithium titanium oxide. However, it is preferable that the proportion of the negative electrode active material other than lithium titanium oxide in the total amount of the negative electrode active material is 30% by mass or less.

[0053] The solid electrolyte of the negative electrode 202 is not particularly limited as long as it has lithium ion conductivity, and for example, a sulfide-based solid electrolyte, a hydride-based solid electrolyte, an oxide-based solid electrolyte, or the like can be used.

[0054] Examples of sulfide-based solid electrolytes include Li ２ S-P ２ S ５ , Li ２ S-SiS ２ , Li ２S-P ２ S ５ -GeS ２ , Li ２ S-B ２ S ３ In addition to the above, Lithium-ion-conducting glass has been attracting attention in recent years as a material with high lithium ion conductivity. １０ GeP ２ S １２ (LGPS system) and Li ６ P.S. ５ Among these, argyrodite-based materials are preferably used because they have particularly high lithium ion conductivity and high chemical stability.

[0055] Examples of hydride-based solid electrolytes include LiBH ４ , LIBH ４ and a solid solution of the following alkali metal compound (e.g., LiBH ４ and the alkali metal compound in a molar ratio of 1:1 to 20:1. The alkali metal compound in the solid solution may be at least one selected from the group consisting of lithium halides (LiI, LiBr, LiF, LiCl, etc.), rubidium halides (RbI, RbBr, RbiF, RbCl, etc.), cesium halides (CsI, CsBr, CsF, CsCl, etc.), lithium amide, rubidium amide, and cesium amide.

[0056] Examples of oxide-based solid electrolytes include Li ７ La ３ Zr ２ O １２ , LiTi(PO ４ ) ３ , LiGe(PO ４ ) ３ , LiLaTiO ３ Examples include:

[0057] As the solid electrolyte, one or more of the solid electrolytes exemplified above can be used. Among the solid electrolytes exemplified above, it is more preferable to use a sulfide-based solid electrolyte because it has high lithium ion conductivity and also has the function of improving the formability of the negative electrode mixture.

[0058] As the conductive additive for the negative electrode 202, for example, a carbon material such as carbon black can be used.

[0059] The negative electrode mixture may or may not contain a binder. When the negative electrode mixture contains a binder, a fluororesin such as polyvinylidene fluoride (PVDF) can be used as the binder.

[0060] When a current collector is used for the negative electrode 202, the current collector may be made of copper, nickel, stainless steel, or aluminum foil, punched metal, mesh, expanded metal, foamed metal, carbon sheet, or the like.

[0061] The negative electrode 202 can be manufactured by mixing, for example, particles of lithium titanium oxide as an active material, a solid electrolyte, a conductive additive, and the like without using a solvent to prepare a negative electrode mixture, and then molding the mixture into a pellet, etc. Alternatively, the negative electrode 202 may be manufactured by bonding a molded body of the negative electrode mixture obtained as described above to a current collector.

[0062] Alternatively, the above-mentioned anode mixture and a solvent may be mixed to prepare an anode mixture-containing composition, which may be applied to a substrate such as a current collector or the solid electrolyte layer 203 that faces the anode 202, dried, and then pressed to form a molded body of the anode mixture.

[0063] It is preferable to select a solvent that is less likely to deteriorate the solid electrolyte when used in the negative electrode mixture-containing composition. In particular, sulfide-based solid electrolytes and hydride-based solid electrolytes undergo chemical reactions with trace amounts of water, so it is preferable to use a non-polar aprotic solvent such as a hydrocarbon solvent such as hexane, heptane, octane, nonane, decane, decalin, toluene, or xylene. In particular, it is more preferable to use an ultra-dehydrated solvent with a water content of 0.001% by mass (10 ppm) or less. In addition, fluorine-based solvents such as "Vertrel (registered trademark)" manufactured by DuPont-Mitsui Fluorochemicals, "Zeorolla (registered trademark)" manufactured by Nippon Zeon Co., Ltd., and "Novec (registered trademark)" manufactured by Sumitomo 3M Co., Ltd., as well as non-aqueous organic solvents such as dichloromethane and diethyl ether can also be used.

[0064] The composition of the negative electrode mixture is, for example, preferably 50 to 80% by mass of the negative electrode active material, 20 to 50% by mass of the solid electrolyte, and 0.1 to 10% by mass of the conductive additive. When the negative electrode mixture contains a binder, the binder content is preferably 0.1 to 10% by mass. Furthermore, the thickness of the negative electrode mixture compact (including both cases where the negative electrode does not have a current collector and cases where the negative electrode has a current collector) is preferably 50 to 1000 μm.

[0065] A negative electrode tab 207 is attached to the negative electrode 202. The negative electrode tab 207 is made of a metal material such as copper. The negative electrode tab 207 is joined to a negative electrode power supply plate 40 (described later) by welding.

[0066] <Solid Electrolyte Layer 203> The solid electrolyte in the solid electrolyte layer 203 can be one or more of the same solid electrolytes as those exemplified above for the negative electrode 202. However, in order to improve the battery characteristics, it is desirable to contain a sulfide-based solid electrolyte, and it is more desirable to contain a sulfide-based solid electrolyte in all of the positive electrode 201, the negative electrode 202, and the solid electrolyte layer 203.

[0067] The solid electrolyte layer 203 may have a porous body such as a resin nonwoven fabric as a support.

[0068] The solid electrolyte layer 203 is a cylindrically shaped compact (layer) formed by compressing (pressing) a solid electrolyte by pressure molding or the like. The solid electrolyte layer is not limited to a cylindrically shaped layer, and may be a prismatic layer. The solid electrolyte layer may be formed by applying a composition for forming the solid electrolyte layer 203, which is prepared by dispersing the solid electrolyte in a solvent, onto a substrate, a positive electrode, or a negative electrode, drying the composition, and optionally performing pressure molding such as pressing.

[0069] As with the solvent used in the anode mix-containing composition, it is desirable to select a solvent that is less likely to deteriorate the solid electrolyte for use in the composition for forming the solid electrolyte layer 203. The various solvents exemplified above are preferably used as solvents for the anode mix-containing composition, and it is particularly preferable to use an ultra-dehydrated solvent with a water content of 0.001% by mass (10 ppm) or less. The thickness of the solid electrolyte layer 203 is preferably 10 to 200 μm.

[0070] <Arrangement of Battery Molded Bodies 20> In the cell assembly 21, six battery molded bodies 20a, 20b, 20c, 20d, 20e, and 20f are arranged (stacked) in this order from bottom to top along the axis X1. The battery molded bodies 20 are arranged so that the negative electrode 202 faces downward and the positive electrode 201 faces upward. Note that the arrangement is not limited to one in which the negative electrode 202 of the battery molded bodies 20 faces downward, and the positive electrode 201 may also face downward. Furthermore, the battery molded bodies 20 may be arranged in parallel, in series, or in a combination of parallel and series. This allows the battery molded bodies 20 to be arranged according to the required voltage or current and the arrangement space.

[0071] FIG. 4(A) is an external perspective view of one battery molded body 20 (20a, 20b, 20c, 20d, 20e). FIG. 4(B) is an external perspective view of one battery molded body 20 (20f). As described above, the battery molded body 20 is constructed based on a stacked body 211 that has been compression-molded by pressing. In the following description, the thickness direction of the compression-molded stacked body 211, i.e., the thickness direction of the battery molded body 20, is referred to as the first direction L1. It can also be said that the multiple battery molded bodies 20 stacked along the axis X1 are stacked along the first direction L1.

[0072] The positive electrode tab 206 connected to the positive electrode 201 of the battery molded body 20 has a main portion 206a and a connection portion 206b. The main portion 206a is formed in a plate shape extending in a direction intersecting the first direction L1. The main portion 206a is joined to the polar sheet 201a attached to the positive electrode 201 by, for example, resistance welding, and is electrically connected to the positive electrode 201.

[0073] 4A, the connecting portion 206b provided on the battery molded bodies 20a, 20b, 20c, 20d, and 20e is connected to one end of the main portion 206a and extends along a first direction L1, which is a direction intersecting the main portion 206a. In this embodiment, the direction intersecting the main portion 206a is a direction perpendicular to the main portion 206a.

[0074] As shown in FIG. 4B , the positive electrode tab 206 provided on the uppermost battery molded body 20f has a connection portion 206b formed via a rising portion 206c extending upward from the end of the main portion 206a along the first direction L1. The connection portion 206b extends along the first direction L1. As will be described in detail later, the connection portion 206b is bent after being housed in the holder 22, which will be described later, and extends in a direction intersecting the first direction L1. In this embodiment, the direction in which the connection portion 206b extends intersecting the first direction L1 is a direction perpendicular to the first direction L1.

[0075] The connection portion 206b is joined to the positive electrode power supply plate 30 by resistance welding or the like, thereby electrically connecting the positive electrode 201 of the battery molded body 20 and the positive electrode power supply plate 30.

[0076] The negative electrode tab 207 connected to the negative electrode 202 of the battery molded body 20 has a main portion 207a and a connection portion 207b. The main portion 207a is formed in a plate shape extending in a direction intersecting the first direction L1. The main portion 207a is joined to a polar sheet 202a attached to the negative electrode 202 by, for example, resistance welding, and is electrically connected to the negative electrode 202.

[0077] The connecting portion 207b is connected to an end of the main portion 207a and extends along a first direction L1 that intersects with (specifically, is perpendicular to) the main portion 207a. The connecting portion 207b extends from the surface of the negative electrode 202 along the first direction L1 toward the positive electrode 201.

[0078] 4(A) and 4(B), the negative electrode tab 207 is attached at a position where the connection portion 207b of the negative electrode tab 207 and the connection portion 206b of the positive electrode tab 206 are symmetrical with respect to the central axis of the cylindrical battery molded body 20 (i.e., where the connection portion 206b and the connection portion 207b face each other). The connection portion 207b is joined to the negative electrode power supply plate 40 by, for example, resistance welding. This electrically connects the negative electrode 202 of the battery molded body 20 and the negative electrode power supply plate 40.

[0079] 2 and 3, insulating plates 210 made of a soft elastic material such as silicone rubber are disposed between the battery molded bodies 20. Specifically, insulating plate 210a is disposed between the upper surface of battery molded body 20a and the lower surface of battery molded body 20b. Insulating plate 210b is disposed between the upper surface of battery molded body 20b and the lower surface of battery molded body 20c. Insulating plate 210c is disposed between the upper surface of battery molded body 20c and the lower surface of battery molded body 20d. Insulating plate 210d is disposed between the upper surface of battery molded body 20d and the lower surface of battery molded body 20e. Insulating plate 210e is disposed between the upper surface of battery molded body 20e and the lower surface of battery molded body 20f.

[0080] The insulating plate 210 is formed into a disk shape corresponding to the cylindrical shape of each battery molded body 20. Note that the insulating plate 210 is not limited to being formed into a disk shape, but is formed into a shape corresponding to the shape of the battery molded body 20. For example, if the battery molded body 20 is prismatic, the insulating plate 210 is formed into a polygonal plate shape.

[0081] The insulating plate 210 allows the battery molded bodies 20a, 20b, 20c, 20d, 20e, and 20f to be arranged in an insulated state. The insulating plate 210, which is a soft elastic body, buffers impacts in the direction of the axis X1 on the battery molded bodies 20 stacked along the axis X1. The insulating plate 210, which is a soft elastic body, also prevents load stress from being applied to the joints between the positive electrode tabs 206 and the negative electrode tabs 207 of the battery molded bodies 20 stacked along the axis X1.

[0082] <Holder 22> The holder 22 holds the plurality of battery molded bodies 20 arranged along the axis X1 (first direction L1). The holder 22 is made of a resin material, such as polypropylene, that is insulating, flex-resistant, and non-water-absorbent. The holder 22 has a first holding portion 23 and a second holding portion 24. The first holding portion 23 holds the lower and side surfaces of the plurality of stacked battery molded bodies 20. The second holding portion 24 holds the upper part of the uppermost battery molded body 20f of the plurality of stacked battery molded bodies 20.

[0083] As shown in Fig. 3, the first holding portion 23 has a bottom holding portion 231 and four side holding portions 232. The number of side holding portions 232 is not limited to four and may be more or less than four. The bottom holding portion 231 is a circular plate that matches the shape of the cylindrical battery molded body 20. If the battery molded body 20 is prismatic, the bottom holding portion 231 is formed in a polygonal plate shape.

[0084] The side supporting portions 232 extend along the axis X1 and are connected at their lower ends to the bottom supporting portions 231. The four side supporting portions 232 are provided at intervals of, for example, 90 degrees in the circumferential direction of the bottom supporting portion 231. A hook-shaped bent portion 232a is formed on the upper part of each side supporting portion 232.

[0085] Fig. 5(A) is a perspective view of the appearance of the first holding portion 23 during molding. As shown in Fig. 5(A), each of the four side holding portions 232 extends radially outward from the circumference of the bottom holding portion 231. By bending the side holding portion 232 in the A1 direction shown in Fig. 5(A) around a bent portion 232b near the connection point with the bottom holding portion 231 as a fulcrum, the first holding portion 23 takes on the shape shown in Fig. 3.

[0086] The battery molded body 20, which will be described later, is housed in the space surrounded by the bottom holding portion 231 and the side holding portion 232. When the battery molded body 20 is housed, as shown in Fig. 3, the bent portion 232a of the side holding portion 232 is inclined radially outward from the axis X1. Therefore, the upper end of the side holding portion 232 does not get in the way when the battery molded body 20 is housed in the first holding portion 23, improving workability.

[0087] 3, a sheet 233 made of, for example, a silicone material is disposed between the bottom holding portion 231 and the battery molded body 20a. The sheet 233 is provided to facilitate rotation of the battery molded body 20 relative to the holder 22 when manufacturing the cell assembly 21, which will be described in detail later. Rotating the battery molded body 20 on the sheet 233 facilitates the position adjustment process of aligning the positive electrode tabs 206 and the negative electrode tabs 207 of each battery molded body 20 housed in the holder 22 in the direction of the axis X1. The sheet 233 does not have to be disposed.

[0088] When the battery molded body 20 is housed in the first holding section 23, the upper portion of the side holding section 232 is bent in the A2 direction shown in FIG. 3 , with the lower end 232c of the bent section 232a as a fulcrum. As a result, the contact surface 232d of the bent section 232a above the lower end 232c comes into contact with the upper surface of the uppermost battery molded body 20f. An upper tip 232e formed at the upper end of the side holding section 232 above the contact surface 232d extends upward along the axis X1. A latch portion that protrudes outward is formed on the upper tip 232e.

[0089] 5B is an external perspective view of the second holding portion 24. The second holding portion 24 has two semicircular portions 240 and 241 and a rectangular storage portion 242. The storage portion 242 is provided between the semicircular portions 240 and 241, and is connected to the semicircular portion 240 at one wall surface and is connected to the semicircular portion 241 at the wall surface opposite the one wall surface. The upper surface of the storage portion 242 is lower than the upper surfaces of the semicircular portions 240 and 241. In other words, the storage portion 242 forms a recess relative to the semicircular portions 240 and 241.

[0090] The connection portion 206b of the positive electrode tab 206 provided on the uppermost battery molded body 20f, which is bent in a direction intersecting the axis X1 (i.e., the first direction L1), is accommodated in the upper surface of the accommodation portion 242. Furthermore, the accommodation portion 242 accommodates a contact connection portion 302 of the positive electrode power supply plate 30 (described later) above the accommodated connection portion 206b.

[0091] Two accommodation openings 243 are formed in each of the semicircular portions 240 and 241 along the circumferential direction, for example, at 90-degree intervals. The accommodation openings 243 are through-holes that vertically penetrate the semicircular portions 240 and 241. The circumferential length of the accommodation openings 243 is approximately equal to the width of the side supporting portion 232 of the first supporting portion 23, and the radial length of the accommodation openings 243 is approximately equal to the thickness of the side supporting portion 232.

[0092] When the second holding portion 24 is placed above the battery molded body 20f, the upper tip 232e of the side holding portion 232 of the first holding portion 23 is inserted into the accommodation opening 243. When the upper tip 232e is inserted into the accommodation opening 243, a latch portion formed on the upper tip 232e engages with the upper surfaces of the semicircular portions 240 and 241, and the second holding portion 24 is fixed to the first holding portion 23.

[0093] An attachment recess 244 is formed between the two accommodation openings 243 of the semicircular portion 240 and between the two accommodation openings 243 of the semicircular portion 241. As will be described in detail later, an adhesive is applied to the attachment recess 244 to adhere and fix the cell assembly 21 to the battery can 10 after the cell assembly 21 is accommodated in the battery can 10.

[0094] <Positive Electrode Power Supply Plate 30> The positive electrode power supply plate 30 is made of a metal material such as nickel or aluminum, and electrically connects the positive electrode 201 of the battery molded body 20 to an electrode terminal of the can lid portion 50, which will be described later. The positive electrode power supply plate 30 has a tab connection portion 301 and a contact connection portion 302. The tab connection portion 301 is formed in a plate shape with long sides along the axis X1. The tab connection portion 301 is joined to the positive electrode tabs 206 attached to the battery molded bodies 20a, 20b, 20c, 20d, and 20e by, for example, resistance welding.

[0095] The contact connection portion 302 is formed by bending the positive electrode power supply plate 30, and is connected to the upper end of the tab connection portion 301. The contact connection portion 302 is housed in a housing portion 242 formed on the upper surface of the second holding portion 24 of the holder 22. The lower surface of the contact connection portion 302 is joined to the positive electrode tab 206 of the battery molded body 20f housed in the housing portion 242 of the second holding portion 24, for example, by resistance welding.

[0096] The vicinity of the upper end of the tab connection portion 301 of the positive power supply plate 30 and the contact connection portion 302 are not covered with the above-mentioned heat shrink tube 213. Therefore, a positive insulating seal 215 is attached, for example, by adhesive, near the upper end of the tab connection portion 301 of the positive power supply plate 30, i.e., near the position where it is connected to the contact connection portion 302.

[0097] <Negative electrode power supply plate 40> The negative electrode power supply plate 40 is a member that electrically connects the negative electrode 202 of the battery molded body 20 and the battery can 10. Specifically, the negative electrode power supply plate 40 is a plate-shaped member having long sides along the axis X1. The negative electrode power supply plate 40 is made of a metal material such as nickel or copper. The negative electrode power supply plate 40 is joined to the negative electrode tabs 207 attached to the negative electrodes 202 of each of the multiple battery molded bodies 20 by, for example, resistance welding.

[0098] The upper end of the negative electrode power supply plate 40 protrudes above the upper end of the cell assembly 21. Two upper end portions 401, 402 are formed at the upper end of the negative electrode power supply plate 40. That is, the upper end portions 401, 402 are also not covered with the heat shrink tubing 213. Each of these two upper end portions 401, 402 is joined to the inner wall surface of the side surface 102 of the battery can 10 by welding or the like. Note that the negative electrode power supply plate 40 may not be formed with the upper end portions 401, 402, but may instead have a single upper end portion.

[0099] <Can lid portion 50> The can lid portion 50 is attached to the upper end, which is one end of the battery can 10, to seal the opening of the battery can 10. The can lid portion 50 is press-fitted into the upper end of the battery can 10, and then joined to the battery can 10 by, for example, laser welding, to seal the opening of the battery can 10.

[0100] Fig. 6(A) is a perspective view of the upper side of the can lid 50, and Fig. 6(B) is a perspective view of the lower side of the can lid 50. The can lid 50 has a main body 51, an electrode terminal 52, an insulating part 53, and an insulating sheet 54.

[0101] The main body 51 is made of, for example, a metal material and has a disk shape corresponding to the shape of the opening of the battery can 10. As shown in FIG. 6(B) , an insulating sheet 54 is provided on the lower surface of the main body 51. The lower surface of the main body 51 is the surface that faces the bottom surface 101 of the battery can 10 when the can lid 50 is attached to the battery can 10. A curved surface 510 is formed on the outer periphery of the lower surface of the main body 51. The curved surface 510 functions as a guide when fitting the can lid 50 into the opening of the battery can 10. An opening 511 is formed in the center of the can lid 50. The opening 511 is a through-hole that passes through the main body 51 in the vertical direction.

[0102] The insulating portion 53 is made of a non-conductive material such as a sintered glass material or a sintered ceramic material. The insulating portion 53 is provided in the opening 511 of the main body 51. An opening 531 is formed in the center of the insulating portion 53. The opening 531 is a through-hole that passes through the insulating portion 53 in the vertical direction.

[0103] The electrode terminal 52 is made of a conductive material and is disposed in the opening 531. The electrode terminal 52 is cylindrical and is formed by a first protrusion 521 and a second protrusion 522. The first protrusion 521 protrudes upward beyond the upper surface of the main body 51. The first protrusion 521 comes into contact with an electrical contact or the like of a device or the like in which the all-solid-state battery 1 is mounted.

[0104] The second protrusion 522 protrudes downward from the lower surface of the main body 51. That is, when the can lid 50 is attached to the battery can 10, the second protrusion 522 protrudes toward the bottom surface 101 of the battery can 10. The amount by which the first protrusion 521 protrudes from the main body 51 is greater than the amount by which the second protrusion 522 protrudes from the main body 51.

[0105] The second protrusion 522 protrudes downward by 0.1 mm relative to the insulating sheet 54 provided on the lower surface of the main body 51. The insulating sheet 54 is made of, for example, a resin material and has a thickness of about 0.1 mm. Therefore, the downward protrusion amount of the second protrusion 522 is about 0.2 mm. In other words, the protrusion amount of the second protrusion 522 is about 0.1 mm larger than the thickness of the insulating sheet 54.

[0106] The second protrusion 522 is electrically connected to the above-described positive power supply plate 30. Specifically, the second protrusion 522 is joined to the connection power supply plate 60 (described later) by, for example, resistance welding. Note that when the positive power supply plate 30 is joined to the battery can 10, the negative power supply plate 40 is electrically connected to the second protrusion 522.

[0107] The main body 51, the electrode terminals 52, and the insulating portion 53 are integrally molded. Specifically, when the insulating portion 53 is a sintered glass material, glass powder, which is the material of the insulating portion 53, is molded by press molding or the like, as described below. At this time, the insulating portion 53 is formed into a cylindrical shape that can be inserted into the opening 511 of the main body 51 and to which the electrode terminals 52 can be attached. The main body 51, the electrode terminals 52, and the insulating portion 53 are integrally molded by sintering the glass material of the insulating portion 53 in an electric furnace or the like using a glass hermetic method.

[0108] <Connection Power Supply Plate 60> The connection power supply plate 60 is a plate-shaped member made of a conductive metal material, such as stainless steel, aluminum, or a nickel alloy. An electric wire may also be used as the connection power supply plate 60. As shown in FIG. 2 , the plate-shaped member has a folded shape formed by being alternately bent (folded) in opposite directions at multiple bending points (three bending points in FIG. 2 ). One end of the connection power supply plate 60 is joined to the second protrusion 522 of the electrode terminal 52 provided on the can lid 50 by, for example, resistance welding, laser welding, brazing, or the like. The other end of the connection power supply plate 60 is joined to the contact connection portion 302 of the positive power supply plate 30 by, for example, resistance welding, laser welding, brazing, or the like. When the positive power supply plate 30 is joined to the battery can 10, the other end of the connection power supply plate 60 is joined to the negative power supply plate 40.

[0109] 7A is a perspective view of the lower side of the can lid 50 with the connection feed plate 60 joined to the second protrusion 522. As shown in FIG. 7A, the width D1 of one end of the connection feed plate 60 is equal to or greater than the diameter D2 of the second protrusion 522. Therefore, the contact area between the joined connection feed plate 60 and the second protrusion 522 can be increased compared to when the width D1 is less than the diameter D2. As a result, the resistance at the joint between the connection feed plate 60 and the electrode terminal 52 can be reduced.

[0110] 7B is an enlarged cross-sectional view of region B surrounded by the two-dot chain line in FIG. 2. As shown in FIG. 7B, connection feed plate 60 is folded back at bending points P1, P2, and P3. By folding connection feed plate 60 back at bending points P1, P2, and P3, first flat portion 601, second flat portion 602, third flat portion 603, fourth flat portion 604, first curved portion 605, second curved portion 606, and third curved portion 607 are formed.

[0111] The first flat portion 601, the second flat portion 602, the third flat portion 603, and the fourth flat portion 604 each extend in a direction intersecting (orthogonal to) the axis X1 and are accommodated inside the battery can 10 and the can lid 50 in an overlapping state with a gap in the axis X1 direction. The first curved portion 605 is a portion connecting the first flat portion 601 and the second flat portion 602 and is formed by bending the connection power feed plate 60 at a bending point P1. The second curved portion 606 is a portion connecting the second flat portion 602 and the third flat portion 603 and is formed by bending the connection power feed plate 60 at a bending point P2. The third curved portion 607 is a portion connecting the third flat portion 603 and the fourth flat portion 604 and is formed by bending the connection power feed plate 60 at a bending point P3.

[0112] A part (e.g., one end) of the first flat portion 601 is one end of the connection power supply plate 60 and is joined to the electrode terminal 52. A part (e.g., one end) of the fourth flat portion 604 is the other end of the connection power supply plate 60 and is joined to the positive power supply plate 30. As described above, the second protrusion 522 of the electrode terminal 52 protrudes downwardly beyond the insulating sheet 54, thereby preventing the connection power supply plate 60 from coming into contact with the main body 51 and causing a short circuit. Furthermore, even when a high impact force is applied to the all-solid-state battery 1, a momentary disconnection between the connection power supply plate 60 and the electrode terminal 52, a momentary disconnection between the positive power supply plate 30 (i.e., the battery molded body 20) and the connection power supply plate 60, and an increase in contact resistance due to rubbing of the contact surfaces are suppressed, thereby suppressing a decrease in the output voltage of the battery and the occurrence of chattering.

[0113] <Method of Manufacturing All-Solid-State Battery 1> A method of manufacturing the all-solid-state battery 1 will be described with reference to the flowchart shown in FIG. 8 . In the first process shown in step S1, a battery molded body 20 is manufactured. In this case, a laminate 211 in which a positive electrode 201, a negative electrode 202, and a solid electrolyte layer 203 are stacked is formed by applying pressure using, for example, a press or the like. A positive electrode tab 206 is manufactured from a metal material such as aluminum, and a negative electrode tab 207 is manufactured from a metal material such as copper. The positive electrode tab 206 is then bonded to a polar sheet 201a provided on the positive electrode 201 of the laminate 211. The negative electrode tab 207 is then bonded to a polar sheet 202a provided on the negative electrode 202 of the laminate 211.

[0114] In the second process shown in step S2, the cell assembly 21 is manufactured. In this case, a plurality of battery molded bodies 20, each manufactured by joining a positive electrode tab 206 and a negative electrode tab 207 to a laminate 211, are stacked. Then, a positive electrode power supply plate 30 and a negative electrode power supply plate 40 are attached, thereby manufacturing the cell assembly 21.

[0115] Depending on the production line, the step of joining the positive electrode tab 206 and the negative electrode tab 207 to the laminate 211, which is performed in the first step of step S1 described above, may be performed in the second step of step S2. In this case, in the second step of step S2, the positive electrode tab 206 and the negative electrode tab 207 are joined to the laminate 211 to produce the battery molded body 20, and then the cell assembly 21 is produced. Furthermore, the positive electrode 201, the negative electrode 202, and the solid electrolyte layer 203 of the laminate 211 are stacked along a first direction L1, which is the thickness direction, and the multiple battery molded bodies 20 in the cell assembly 21 are stacked along the first direction L1.

[0116] In the third process shown in step S3, the cell assembly 21 is housed in the battery can 10. At this time, the cell assembly 21 is housed in the battery can 10 so that the first direction L1 in which the multiple battery molded bodies 20 are stacked is aligned with the axis X1 of the battery can 10.

[0117] In the fourth process shown as step S4, the can lid 50 is manufactured. In this case, the can lid 50 is manufactured by integrally molding an insulating part 53 formed by compressing an insulating material, a main body 51, and an electrode terminal 52. Note that the fourth process does not necessarily have to be performed after the third process, but may be performed before the first process, the second process, or the third process.

[0118] In the fifth process shown in step S5, the can lid 50 is attached to the opening on one side of the axis X1 of the battery can 10, thereby sealing the opening of the battery can 10. In this way, the all-solid-state battery 1 is manufactured. Each process will be described in detail below.

[0119] <First Step (Manufacturing Battery Molded Body 20)> In the first step, a positive electrode mixture, a negative electrode mixture, and a solid electrolyte are first molded into a laminate 211. Then, a positive electrode tab 206 is attached to the positive electrode 201 of the laminate 211, and a negative electrode tab 207 is attached to the negative electrode 202, thereby manufacturing the battery molded body 20.

[0120] <Forming of Laminate 211> Figures 9(A) to 9(C) are diagrams schematically illustrating the forming process of the laminate 211. The laminate 211 is produced by compressing a solid (powder) material placed in a mold using a press or the like. Specifically, first, the above-described solid electrolyte is placed in a lower die 81 inside a cylindrical compression press die 80. As shown in Figure 9(A), an upper die 82 is placed on top of the solid electrolyte, and the upper die 82 is compressed by a press or the like in a first compression direction indicated by arrow A3 in the figure. This produces a provisionally formed layer 203b of the solid electrolyte layer 203.

[0121] 9(B) , a cathode mixture constituting the cathode 201 is placed on the provisionally molded layer 203b of the solid electrolyte layer 203, and a polar sheet 201a is placed on the cathode mixture. Then, the polar sheet 201a, the cathode mixture, and the provisionally molded layer 203b are compressed by a press or the like along the first compression direction A3 via the upper pressing die 82. As a result, the provisionally molded layer 201b of the cathode 201 and the polar sheet 201a are formed on top of the provisionally molded layer 203b of the solid electrolyte layer 203.

[0122] 9(C), the provisionally molded layer 203b of the solid electrolyte layer 203, the provisionally molded layer 201b of the positive electrode 201, and the polar sheet 201a are turned upside down. In this case, the provisionally molded layer 203b of the solid electrolyte layer 203, the provisionally molded layer 201b of the positive electrode 201, and the polar sheet 201a may be temporarily removed from the compression press mold 80, turned upside down, and then placed in the compression press mold 80 again.

[0123] The assembly is then removed from the compression press mold 80 and turned upside down, and the anode mixture 202b constituting the anode 202 is placed on the provisionally molded layer 203b of the solid electrolyte layer 203, i.e., on the side of the provisionally molded layer 203b of the solid electrolyte layer 203 that does not face the provisionally molded layer 201b of the positive electrode 201. A polar sheet 202a is placed on the anode mixture 202b. The polar sheet 202a, the anode mixture 202b, the provisionally molded layer 203b of the solid electrolyte layer 203, the provisionally molded layer 201b of the positive electrode 201, and the polar sheet 201a are compressed along the first compression direction A3 via the lower press mold 81 using a press or the like. This compresses the anode mixture 202b, the provisionally molded layer 203b of the solid electrolyte layer 203, and the provisionally molded layer 201b of the positive electrode 201. As a result, a laminate 211 is formed, which has a solid electrolyte layer 203, a layered anode 202 on one side of the solid electrolyte layer 203, and a layered cathode 201 on the other side of the solid electrolyte layer 203.

[0124] By being compressed along the first compression direction A3, the stack 211 is formed into a shape having a thickness in a predetermined direction along the first compression direction A3. In the stack 211, the positive electrode 201, the solid electrolyte layer 203, and the negative electrode 202 are stacked along the predetermined direction. In other words, the stacking direction of the positive electrode 201, the solid electrolyte layer 203, and the negative electrode 202 is aligned with (coincides with) the first direction L1 and the first compression direction A3.

[0125] 10A is a perspective view of the appearance of the molded laminate 211. The laminate 211 is molded into a columnar shape by being compressed in a cylindrical compression press die 80. When the compression press die 80 has a rectangular tube shape, the laminate 211 made up of the positive electrode 201, the solid electrolyte layer 203, and the negative electrode 202 has a rectangular columnar shape. As described above, the laminate 211 has a thickness along the first direction L1.

[0126] 10(B) is a plan view of the laminate 211, which schematically shows the directions in which the positive electrode 201, the solid electrolyte layer 203, and the negative electrode 202 are elongated by compression when the laminate 211 is compressed and molded. Specifically, FIG. 10(B) schematically shows the laminate 211 in a plane perpendicular to the first direction L1.

[0127] During molding, the laminate 211 is compressed in the first compression direction A3, and is therefore stretched in the A4 direction along the radial direction from the center of the laminate 211 to the radially outer side. Therefore, when the molded laminate 211 is placed in a high-temperature environment, the laminate 211 has a high resistance to high-temperature expansion in the A4 direction.

[0128] Fig. 10C is a plan view of the laminate 211, schematically illustrating the direction of the force remaining in the laminate 211 after the laminate 211 is compressed. Specifically, Fig. 10C schematically illustrates the laminate 211 in a plane perpendicular to the first direction L1.

[0129] In the molded laminate 211, strain applied to the powder material during compression causes a residual force in the A5 direction along the radial direction from the outer periphery toward the center of the laminate 211. Therefore, when the molded laminate 211 is placed in a low-temperature environment, the laminate 211 has a high resistance to low-temperature shrinkage in the A5 direction.

[0130] That is, the laminate 211 has strong resistance to high-temperature expansion and low-temperature contraction in a direction intersecting the first direction L1. In other words, the laminate 211 is less likely to crack, collapse, bend, or the like due to temperature changes in a direction intersecting the first direction L1. In contrast, the laminate 211 has weaker resistance to high-temperature expansion and low-temperature contraction in the first direction L1, which is the thickness direction of the laminate 211, compared to a direction intersecting the first direction L1. For this reason, when a force is applied along the first direction L1 in a high-temperature environment exceeding 60°C (e.g., an environment of approximately 60°C to 125°C) or a low-temperature environment below -20°C (e.g., an environment of approximately -20°C to -50°C), the laminate 211 is more likely to crack, collapse, bend, or the like compared to a direction intersecting the first direction L1.

[0131] <Manufacturing of Battery Molded Body 20> The battery molded body 20 is manufactured by attaching the heat shrink tube 212, the positive electrode tab 206, and the negative electrode tab 207 to the laminated body 211 produced as described above. Since the battery molded body 20 is manufactured by attaching the heat shrink tube 212, the positive electrode tab 206, and the negative electrode tab 207 to the laminated body 211, it can also be said that the battery molded body 20 is manufactured by compressing it in the first compression direction A3.

[0132] 11(A) to 11(C) are diagrams showing the manufacturing process of the battery molded body 20. The cylindrically formed laminate 211 shown in FIG. 10(A) is inserted into a cylindrical heat-shrinkable tube 212 shown in FIG. 11(A). When the heat-shrinkable tube 212 is heated in this state, it shrinks. As a result, the side surfaces and the peripheries of the top and bottom surfaces of the laminate 211 are covered with the heat-shrinkable tube 212, as shown in FIG. 11(B).

[0133] Attaching the heat-shrinkable tube 212 prevents separation of the laminate 211 and the polar sheets 201 a, 202 a. Furthermore, because the heat-shrinkable tube 212 is made of a non-conductive material, when the battery molded body 20 is housed in the battery can 10, it is possible to insulate the battery molded body 20 from the metal battery can 10.

[0134] 11(C), a positive electrode tab 206 and a negative electrode tab 207 are joined by, for example, resistance welding to the laminate 211 with the heat-shrinkable tube 212 attached. Specifically, the positive electrode tab 206 is joined to a polar sheet 201a provided on one surface of the laminate 211, i.e., the surface on which the positive electrode 201 is formed. Furthermore, the negative electrode tab 207 is joined to a polar sheet 202a provided on the other surface of the laminate 211, i.e., the surface on which the negative electrode 202 is formed. In this way, the battery molded body 20 shown in FIGS. 4(A) and 4(B) is manufactured.

[0135] FIG. 11C shows the case where the battery molded bodies 20a, 20b, 20c, 20d, and 20e shown in FIG. 4A are manufactured.

[0136] The heat shrink tube 212 may also be attached after the positive electrode tab 206 and the negative electrode tab 207 are bonded to the polar sheets 201a and 202a, respectively.

[0137] <Second Step (Manufacturing the Cell Assembly 21)> Next, the second step will be described in detail with reference to the external perspective views of the cell assembly 21 in the middle of manufacture shown in Figures 12(A) to 16. In the second step, the multiple battery molded bodies 20 manufactured in the first step are stacked along the first direction L1 inside the holder 22. Then, a positive electrode power supply plate 30 is joined to each positive electrode tab 206 of the multiple battery molded bodies 20 held in the holder 22, and a negative electrode power supply plate 40 is joined to each negative electrode tab 207.

[0138] <Stacking of battery molded bodies 20> First, the first holding portion 23 of the holder 22 is deformed into a shape that can accommodate the battery molded body 20. Specifically, the first holding portion 23 during molding shown in Fig. 5(A) is bent in the A1 direction around the bent portions 232b of the four side holding portions 232 as fulcrums, thereby deforming into a shape that can accommodate the battery molded body 20 as shown in Fig. 3.

[0139] A plurality of battery molded bodies 20 are stacked in a stacking direction along the first direction L1 on the bottom surface holding portion 231 of this first holding portion 23. As described above, an insulating plate 210 is disposed between the plurality of battery molded bodies 20. When a sheet 233 is disposed, the sheet 233 is provided between the bottom surface holding portion 231 and the battery molded body 20a in the lowest layer.

[0140] 12(A) and 12(B) are external perspective views of the cell assembly 21 in which a plurality of battery molded bodies 20 are stacked on the first holding portion 23. As shown in Fig. 12(A), the battery molded bodies 20 are stacked so that the negative electrode tabs 207 of each battery molded body 20 are aligned in a row along the stacking direction (first direction L1). Although not shown in Fig. 12(A), the positive electrode tabs 206 are also aligned in a row along the stacking direction.

[0141] In the state shown in Fig. 12(A), the upper bent portion 232a of the side supporting portion 232 is bent in the A2 direction with the lower end portion 232c as a fulcrum. As a result, as shown in the external perspective view of Fig. 12(B), the contact surface 232d of the bent portion 232a comes into contact with the upper surface of the uppermost battery molded body 20f. The upper tip portion 232e formed at the upper end of the contact surface 232d extends along the first direction L1.

[0142] When multiple battery molded bodies 20 are stacked within the first holding section 23, the second holding section 24 is attached to the top of the uppermost battery molded body 20f. FIG. 13A is an external perspective view of the cell assembly 21 with the second holding section 24 attached. As shown in FIG. 13A, the upper tip 232e of the first holding section 23 is inserted into the housing opening 243 of the second holding section 24. As described above, the latch portion formed on the upper tip 232e engages with the upper surface of the second holding section 24, thereby fixing the second holding section 24 to the first holding section 23. As a result, the battery molded body 20 is held from above by the second holding section 24.

[0143] As shown in Fig. 13(A), the positive electrode tab 206 of the uppermost battery molded body 20f protrudes upward beyond the second holding portion 24. This positive electrode tab 206 is bent in the A4 direction. As a result, as shown in Fig. 13(B), the connection portion 206b of the positive electrode tab 206 of the battery molded body 20f is accommodated in the accommodation portion 242, which is a recess formed in the upper surface of the second holding portion 24.

[0144] Thereafter, the positive power supply plate 30 and the negative power supply plate 40 are joined. Fig. 14(A) is an external perspective view of the cell assembly 21 showing the state in which the positive power supply plate 30 is joined. In this case, the tab connection portion 301 of the positive power supply plate 30 is joined by resistance welding or the like to the positive tab 206 attached to the battery molded body 20a, 20b, 20c, 20d, and 20e. In addition, the lower surface of the contact connection portion 302 of the positive power supply plate 30 is joined by resistance welding or the like to the upper surface of the connection portion 206b of the positive tab 206 provided on the battery molded body 20f.

[0145] 14(B) is an external perspective view of the cell assembly 21, showing the state in which the negative power supply plate 40 is joined after the positive power supply plate 30 is joined. As shown in the figure, the negative power supply plate 40 is joined by resistance welding or the like to the negative electrode tabs 207 attached to each of the battery molded bodies 20a, 20b, 20c, 20d, 20e, and 20f. This completes the cell assembly 21. For convenience of explanation, the negative power supply plate 40 is joined after the positive power supply plate 30 is joined, but the positive power supply plate 30 may be joined after the negative power supply plate 40 is joined.

[0146] The side surfaces of the cell assembly 21 are covered with the non-conductive heat-shrinkable tube 213 described above. Specifically, as shown in the external perspective view of FIG. 15 , the cell assembly 21 is inserted into the cylindrical heat-shrinkable tube 213. When the heat-shrinkable tube 213 is heated in this state, the heat-shrinkable tube 213 shrinks. As a result, the side surfaces of the cell assembly 21 are covered with the heat-shrinkable tube 213, as shown in the external perspective view of FIG. 16 .

[0147] That is, the multiple battery molded bodies 20, the holder 22, the positive power supply plate 30, and the negative power supply plate 40 are covered by the heat-shrink tubing 213. However, the second holding portion 24 of the holder 22 arranged on the uppermost surface of the cell assembly 21 is not covered by the heat-shrink tubing 213. That is, the vicinity of the upper end of the tab connection portion 301 of the positive power supply plate 30 and the contact connection portion 302, and the vicinity of the upper ends 401, 402 of the negative power supply plate 40 are not covered by the heat-shrink tubing 213.

[0148] By covering the side surfaces of the cell assembly 21 with the heat-shrinkable tube 213, the multiple battery molded bodies 20 constituting the cell assembly 21 can be fixed together, thereby preventing the battery molded bodies 20 from separating or falling off. Also, the positive power supply plate 30 joined to the positive tab 206 and the negative power supply plate 40 joined to the negative tab 207 are prevented from falling off. Furthermore, when the cell assembly 21 is housed in the battery can 10, the heat-shrinkable tube 213 prevents the positive power supply plate 30 from coming into direct contact with the battery can 10. As a result, the occurrence of a short circuit due to contact between the positive power supply plate 30 and the battery can 10 is prevented.

[0149] 16 , a positive electrode insulating seal 215 is attached, for example, by adhesive, near the upper end of the tab connection portion 301 of the positive electrode power supply plate 30, i.e., near the position where it connects to the contact connection portion 302. Attaching the positive electrode insulating seal 215 prevents the positive electrode power supply plate 30 of the cell assembly 21 housed in the battery can 10 from coming into contact with the battery can 10, thereby preventing a short circuit from occurring. Note that if the upper end portion of the tab connection portion 301 of the positive electrode power supply plate 30 can be covered with the heat-shrinkable tube 213, the positive electrode insulating seal 215 need not be attached.

[0150] <Third Step (Accommodating the Cell Assembly 21 in the Battery Can 10)> Fig. 17 is a perspective view illustrating the step of accommodating the cell assembly 21 in the battery can 10, and Fig. 18 is a perspective view of the battery can 10 with the cell assembly 21 accommodated therein. As shown in Fig. 17 , first, the buffer sheet 105 is accommodated in the battery can 10. Then, the cell assembly 21, to which the heat shrink tube 213 and the positive electrode insulating seal 215 are attached, is moved downward along the axis X1 from above the battery can 10 and inserted into the battery can 10. That is, the cell assembly 21 is placed on the bottom surface 101 of the battery can 10 with the buffer sheet 105 interposed therebetween.

[0151] In addition, in the cell assembly 21 inserted into the battery can 10, the first direction L1, which is the direction in which the multiple battery molded bodies 20 are stacked, is aligned with the axis X1. In other words, the multiple battery molded bodies 20 are stacked along the axis X1 inside the battery can 10. Alternatively, it can be said that the first compression direction A3 of the battery molded body 20 (stacked body 211) is aligned with the axis X1.

[0152] A recess 104 is press-formed in the side surface 102 of the battery can 10, and a protrusion protruding toward the axis X1 is formed on the inner peripheral wall surface of the battery can 10. The side surface of the cell assembly 21 housed in the battery can 10 comes into contact with the protrusion. This prevents the cell assembly 21 from vibrating inside the battery can 10.

[0153] 18 is not covered with the heat shrink tube 213. The upper ends 401, 402 of the negative electrode power supply plate 40 are joined to the battery can 10 by welding or the like. This electrically connects the negative electrode 202 and the battery can 10 via the negative electrode power supply plate 40.

[0154] Thereafter, the cell assembly 21 and the inner peripheral wall surface of the side surface 102 of the battery can 10 are fixed with an adhesive. Specifically, the adhesive is applied to the mounting recess 244 formed in the second holding portion 24 of the holder 22 that is not covered by the heat shrink tube 213, and to the inner peripheral wall surface of the side surface 102 of the battery can 10. As the adhesive, a UV adhesive, an epoxy resin adhesive, a silicone adhesive, or the like can be used.

[0155] The configuration is not limited to one in which the negative electrode power supply plate 40 is joined to the battery can 10. The positive electrode power supply plate 30 may be joined to the battery can 10. In this case, the negative electrode power supply plate 40 may be configured to contact an electrode terminal 52 of the can lid portion 50, which will be described later.

[0156] <Fourth Step (Manufacturing the Can Lid 50)> As described above, the can lid 50 is integrally formed from the main body 51 and the electrode terminal 52, which are made of a conductive material such as a metal, and the insulating part 53, which is made of an insulating material. When forming the can lid 50, first, powder, which is the material for the insulating part 53, is molded by press molding or the like. Specifically, it is molded into a cylindrical shape having an outer diameter that can be inserted into the opening 511 of the main body 51 and an inner diameter that can insert the electrode terminal 52.

[0157] 19(A) is a diagram schematically illustrating a molding process of the insulating portion 53. The material (insulating material) 53a of the insulating portion 53 is accommodated in a first compression press die 90. The first compression press die 90 has a cylindrical shape with a bottom surface 901. An axis X2 shown in FIG. 19(A) passes through the center of the bottom surface 901 and is perpendicular to the bottom surface 901.

[0158] The inner diameter of the first compression press die 90 is approximately equal to the diameter of the opening 511 of the main body 51. A cylindrical protrusion 902 having a diameter approximately equal to the diameter of the electrode terminal 52 ( FIG. 2 ) and extending along the axis X2 is formed at the center of the bottom surface 901. The insulating material 53 a is accommodated in a space 904 between the bottom surface 901, an inner peripheral wall surface 903, and the cylindrical protrusion 902 of the first compression press die 90.

[0159] The insulating material 53a accommodated in the first compression press die 90 is compressed downward in a second compression direction A6 along the axis X2 by a second compression press die 91. The second compression press die 91 has a diameter substantially equal to the inner diameter of the first compression press die 90, and has a recess 910 formed in the center thereof having a diameter substantially equal to the diameter of the cylindrical protrusion 902.

[0160] 19(B) is a perspective view of the appearance of the insulating part 53 formed by pressure compression. By being compressed in the cylindrical first compression press die 90, the insulating part 53 is formed into a shape having a thickness in the second direction L2 along the second compression direction A6. Furthermore, because the first compression press die 90 has a cylindrical protrusion 902, the insulating part 53 is formed into a cylindrical shape with an opening 511. Note that if the first compression press die 90 has a rectangular cylindrical shape, the insulating part 53 will also have a rectangular cylindrical shape.

[0161] FIG. 19(C) is a plan view of the insulating portion 53, schematically illustrating the direction in which the insulating portion 53 is stretched when it is molded by compression. Specifically, FIG. 19(C) schematically illustrates the insulating portion 53 in a plane perpendicular to the second direction L2. During molding, the insulating material 53a is compressed in the second compression direction A6 (i.e., the direction along the second direction L2). As a result, the insulating portion 53 is stretched in the direction A7, which extends radially from the interior of the insulating portion 53 toward the outer periphery, and the direction A8, which extends radially from the interior of the insulating portion 53 toward the inner periphery. Therefore, when the molded insulating portion 53 is placed in a high-temperature environment, the insulating portion 53 has high resistance to high-temperature expansion in the directions A7 and A8.

[0162] 19(D) is a plan view of the insulating portion 53, schematically showing the direction of the force remaining in the insulating portion 53 after molding. Due to the strain applied to the powder material during compression, the insulating portion 53 after molding is subjected to a force in the A9 direction, which is directed radially inward from the outer periphery of the insulating portion 53, and a force in the A10 direction, which is directed radially inward from the inner periphery of the insulating portion 53. Therefore, when the insulating portion 53 after molding is placed in a low-temperature environment, the insulating portion 53 has high resistance to low-temperature shrinkage in the A9 and A10 directions.

[0163] That is, the insulating portion 53 has high resistance to high-temperature expansion and low-temperature contraction in a direction intersecting the second direction L2. In other words, the insulating portion 53 is less likely to crack, collapse, bend, or the like due to temperature changes in the direction intersecting the second direction L2. In contrast, the insulating portion 53 has weaker resistance to high-temperature expansion and low-temperature contraction in the second direction L2, which is the thickness direction of the insulating portion 53, compared to the direction intersecting the second direction L2. Therefore, when a force is applied along the second direction L2 in a high-temperature environment exceeding 60°C (e.g., an environment of approximately 60°C to 125°C) or a low-temperature environment below -20°C (e.g., an environment of approximately -20°C to -50°C), the insulating portion 53 is more likely to crack, collapse, bend, or the like in the direction intersecting the second direction L2.

[0164] The insulating part 53 formed as described above is inserted into the opening 511 of the main body part 51. The electrode terminal 52 is inserted into the opening 531 of the insulating part 53. Then, by sintering the insulating material 53a of the insulating part 53, the main body part 51, the electrode terminal 52, and the insulating part 53 are integrally formed as shown in Figures 6(A) and 6(B), and the can lid part 50 is manufactured.

[0165] The insulating sheet 54 described above is attached to the lower surface of the main body 51 of the can lid 50. The first flat portion 601 of the connection power supply plate 60 is joined to the second protrusion 522 of the electrode terminal 52 by resistance welding or the like. As a result, the can lid 50 with the connection power supply plate 60 attached is formed, as shown in FIG. 7B .

[0166] <Fifth Step (Attaching the Can Lid 50 to the Battery Can 10)> In the fifth step, the can lid 50 manufactured in the fourth step is attached to the battery can 10 in which the cell assembly 21 is housed in the third step.

[0167] 20(A) and 20(B) are external perspective views illustrating the process of attaching the can lid 50 to the battery can 10. First, as shown in Fig. 20(A), the connection power supply plate 60 attached to the can lid 50 and the positive power supply plate 30 housed in the battery can 10 are joined by, for example, resistance welding. Specifically, the first flat portion 601 of the connection power supply plate 60 is joined to the contact connection portion 302 of the positive power supply plate 30 housed in the housing portion 242 of the second holding portion 24 of the holder 22.

[0168] 20(B) , with the lower surface of the can lid 50 facing the upper surface of the second holding portion 24, the can lid 50 is moved downward along the axis X1 and press-fitted into the battery can 10. After that, the peripheral edge of the can lid 50 and the upper end of the battery can 10 are joined along the seam by, for example, laser welding. This causes the battery can 10 to be hermetically sealed by the can lid 50. As a result, an all-solid-state battery 1 having the appearance shown in FIG. 1 is manufactured.

[0169] At this time, the can lid 50 is attached to the battery can 10 with the second direction L2, which is the thickness direction of the insulating portion 53, aligned with the axis X1 of the battery can 10. As described above, the cell assembly 21 is housed in the battery can 10 with the first direction L1, which is the thickness direction of the battery body 20, aligned with the axis X1 of the battery can 10. Therefore, when the can lid 50 is attached to the battery can 10, the battery body 20 and the insulating portion 53 are aligned with the axis X1 with the first direction L1 and the second direction L2 aligned (matched). In other words, the battery body 20 and the insulating portion 53 are aligned with the axis X1 in the direction in which they have low resistance to temperature changes. Alternatively, it can be said that the first compression direction A3 of the battery body 20 and the second compression direction A6 of the insulating portion 53 are aligned along the axis X1.

[0170] The hermetically sealing with the can lid 50 is performed in a vacuum environment. In this case, the pressure difference is preferably 1 atmosphere (0.1 MPa). By performing the hermetically sealing in a vacuum environment, the inside of the battery can 10 becomes negative pressure under atmospheric pressure. As a result, the bottom surface 101 of the battery can 10 is recessed inward. By measuring this recess using, for example, a laser displacement meter, it is possible to inspect whether the battery can 10 is hermetically sealed.

[0171] 21 , a buffer member 99 may be attached to the upper surface of the can lid 50 of the all-solid-state battery 1. In this case, the buffer member 99 may be attached to the can lid 50 with weakly adhesive double-sided tape or the like.

[0172] The buffer member 99 is an insulating soft elastic body such as silicone rubber. The buffer member 99 is tubular with an outer diameter substantially equal to the diameter of the can lid 50 and an inner diameter large enough to receive the first protrusion 521 of the electrode terminal 52. The length of the buffer member 99 along the axis X1 is greater than the length of the first protrusion 521 protruding from the can lid 50.

[0173] This prevents the electrode terminal 52 from colliding with the floor or the like when the all-solid-state battery 1 is dropped, thereby preventing the electrode terminal 52 from being damaged by the impact. Also, it prevents the electrode terminal 52 and the battery can 10 from coming into contact with the same plane of a conductive material such as metal, causing a short circuit.

[0174] According to the above-described embodiment, at least one of the following advantageous effects can be obtained.

[0175] (1) The all-solid-state battery 1 includes a battery molded body 20 having a positive electrode 201, a negative electrode 202, and a solid electrolyte layer 203 interposed between the positive electrode 201 and the negative electrode 202, a bottomed cylindrical battery can 10 that houses a cell assembly 21 having a positive electrode power supply plate 30 and a negative electrode power supply plate 40, and a can lid 50 that seals an opening at one end of the battery can 10. The can lid 50 has a conductive electrode terminal 52 and an insulating portion 53 provided around the electrode terminal 52. The battery molded body 20 and the insulating portion 53 are arranged along the axis X1 of the battery can 10. A first compression direction A3 of the battery molded body 20 and a second compression direction A6 of the insulating portion 53 are aligned along the axis X1. An elastic member may be disposed between the cell assembly 21 and the inner surface of the battery can 10.

[0176] When the battery molded body 20 and the insulating portion 53 are arranged in a misaligned manner in the directions (first direction L1 and second direction L2) that have low resistance to external forces in a high-temperature environment or a low-temperature environment, it is necessary to consider impacts in both the first direction L1 and the second direction L2. That is, measures such as providing a buffer member inside the all-solid-state battery 1 or on the device to which the all-solid-state battery 1 is attached to protect against impacts acting from multiple directions are necessary. In contrast, in the present embodiment, the battery molded body 20 and the insulating portion 53 are arranged in a state where the first direction L1 and the second direction L2 are aligned, so that it is sufficient to take measures against impacts acting from a single direction.

[0177] This eliminates the need to consider impacts acting from multiple directions, facilitating the design and manufacture of the impact-resistant structure of the all-solid-state battery 1 and the impact-resistant structure of the device to which the all-solid-state battery 1 is attached. As a result, the all-solid-state battery 1 according to the present embodiment can be used in high-temperature and low-temperature environments, i.e., in environments with a wider temperature range than the temperature range in which existing batteries can be used. In other words, it is possible to provide an all-solid-state battery 1 that can be used in environments with a wider temperature range than existing batteries.

[0178] (2) The plurality of battery molded bodies 20 are stacked inside the battery can 10 along the axis X1. As a result, by taking measures against impacts in a single direction, such as providing an insulating plate 210 made of a soft elastic material along the axis X1, damage to the plurality of battery molded bodies 20 included in the cell assembly 21 can be suppressed. As a result, it is possible to provide an all-solid-state battery 1 that can be used in both high-temperature and low-temperature environments, i.e., in environments with a wide temperature range.

[0179] (3) The connection power supply plate 60 connecting the positive power supply plate 30 and the electrode terminal 52 has a folded shape folded at one or more bending points. This reduces the occurrence of momentary disconnection between the connection power supply plate 60 and the electrode terminal 52, momentary disconnection between the positive power supply plate 30 (i.e., the battery molded body 20) and the connection power supply plate 60, and an increase in contact resistance due to rubbing of the contact surfaces when a high impact force is applied to the all-solid-state battery 1. As a result, a decrease in battery output voltage and the occurrence of chattering are suppressed.

[0180] (4) The electrode terminal 52 has a second protrusion 522 that protrudes further toward the bottom surface 101 of the battery can 10 than the insulating portion 53, and one end of the connection power supply plate 60 is connected to the second protrusion 522, and the other end is connected to the positive electrode power supply plate 30. This makes it possible to electrically connect the electrode terminal 52 to the positive electrode 201 via the positive electrode power supply plate 30.

[0181] (5) The width D1 of one end of the connection power supply plate 60 is equal to or greater than the diameter D2 of the second protrusion 522. This allows for a larger contact area between the joined connection power supply plate 60 and the second protrusion 522 compared to when the width D1 is less than the diameter D2. That is, the resistance value at the joint between the connection power supply plate 60 and the electrode terminal 52 can be reduced. As a result, a larger capacity of power can be supplied from the charged all-solid-state battery 1. For example, when the all-solid-state battery 1 is mounted in a mobile device such as a mobile phone, the standby time of the mobile device can be extended.

[0182] (6) An insulating sheet 54 is provided on the surface of the can lid 50 facing the bottom surface 101 of the battery can 10, and the protrusion amount of the second protrusion 522 is greater than the thickness of the insulating sheet 54. This prevents the connection power supply plate 60 from coming into contact with the main body 51 of the can lid 50 and causing a short circuit.

[0183] (7) The protrusion amount of the second protrusion portion 522 is 0.2 mm. By keeping the protrusion amount of the second protrusion portion 522 along the axis X1 small, a space for accommodating the battery molded body 20 can be secured within the battery can 10. That is, the size of the battery molded body 20 accommodated within the battery can 10 can be increased while preventing the all-solid-state battery 1 from becoming larger, thereby increasing the capacity of the all-solid-state battery 1. Alternatively, if the protrusion amount of the second protrusion portion 522 along the axis X1 is 0.2 mm or less, a space for accommodating the battery molded body 20 can be secured within the battery can 10.

[0184] (8) The multiple battery molded bodies 20 are arranged via insulating plates 210. This allows the multiple battery molded bodies 20 to be arranged in an insulated state, and the insulating plates 210, which are soft elastic bodies, buffer impacts in the direction of the axis X1 on the battery molded bodies 20 stacked along the axis X1. That is, impacts from directions with low resistance to temperature changes are mitigated, preventing damage to the battery molded bodies 20 even in the event of large temperature changes. As a result, the all-solid-state battery 1 can be used in environments with a wide range of temperature changes. Furthermore, the insulating plates 210, which are soft elastic bodies, prevent load stress from being applied to the joints between the positive electrode tabs 206 and the negative electrode tabs 207 of the battery molded bodies 20 stacked along the axis X1.

[0185] Although the embodiments of the present disclosure have been specifically described above, they are not limited to the above-described embodiments and may be modified in various ways without departing from the spirit of the present disclosure. In each embodiment, components may be added, deleted, or replaced, except for essential components. Unless otherwise specified, each component may be singular or plural.

[0186] The all-solid-state battery 1 is not limited to having a plurality of battery molded bodies 20 , and may have one battery molded body 20 .

[0187] The can lid 50 is not limited to having a main body 51 made of a conductive material. For example, the can lid 50 may be integrally formed of an electrode terminal 52 and an insulating portion 53. In this case, the outer diameter of the insulating portion 53 is approximately equal to the inner diameter of the upper end of the battery can 10. The can lid 50 may be attached to the battery can 10 by fixing the outer periphery of the insulating portion 53 to the upper end of the battery can 10 by crimping or the like.

[0188] In the technology according to the present embodiment, the battery molded body (multiple cells) and the insulating portion of the can lid are arranged in the battery can in the direction of least resistance to temperature changes, thereby enabling the all-solid-state battery to be used in environments with a wide range of temperature changes. The present invention, which provides such technology, can contribute to "Build resilient infrastructure, promote inclusive and sustainable industrialization, inclusive and sustainable technological development" of the Sustainable Development Goals (SDGs) proposed by the United Nations.

[0189] 1 All-solid-state battery, 10 Battery can, 20, 20a, 20b, 20c, 20d, 20e, 20f Battery molded body, 21 Cell assembly, 22 Holder, 23 First holding portion, 24 Second holding portion, 30 Positive electrode power supply plate, 40 Negative electrode power supply plate, 50 Can lid portion, 51 Main body portion, 52 Electrode terminal, 53 Insulating portion, 53a Insulating material, 54 Insulating sheet, 60 Connection power supply plate, 101 Bottom surface, 201 Positive electrode, 202 Negative electrode, 203 Solid electrolyte layer, 210, 210a, 210b, 210c, 210d, 210e Insulating plate, 211 Stack, 521 First protrusion, 522 Second protrusion, A3 First compression direction, A6 Second compression direction, D1 Width, D2 Diameter, X1 Axis

Claims

1. An all-solid-state battery comprising: a bottomed, cylindrical battery can that houses a cell assembly having a battery molded body having a positive electrode, a negative electrode, and a solid electrolyte layer interposed between the positive electrode and the negative electrode, a positive electrode power supply plate connected to the positive electrode of the battery molded body, and a negative electrode power supply plate connected to the negative electrode of the battery molded body; and a can lid that seals an opening at one end of the battery can, wherein the can lid has a conductive electrode terminal that is electrically connected to the positive electrode power supply plate or the negative electrode power supply plate, and an insulating part provided around the electrode terminal, wherein the battery molded body and the insulating part are arranged along an axial direction that intersects with a bottom surface of the battery can, and the compression direction of the battery molded body and the insulating part is a direction toward the bottom surface of the battery can that is along the axial direction.

2. The all-solid-state battery according to claim 1, wherein each of the plurality of battery molded bodies is stacked in the battery can along the axial direction.

3. An all-solid-state battery according to claim 2, further comprising a connection power supply plate that connects the positive electrode power supply plate or the negative electrode power supply plate to the electrode terminal, the connection power supply plate having a folded shape folded back at one or more bending points.

4. An all-solid-state battery as defined in claim 3, wherein the electrode terminal has a protrusion that protrudes further toward the bottom surface of the battery can than the insulating portion along an axial direction intersecting with the bottom surface of the battery can, and one end of the connection power supply plate is connected to the protrusion, and the other end is connected to the positive power supply plate or the negative power supply plate.

5. The all-solid-state battery according to claim 4, wherein the width of the one end of the connection power supply plate is equal to or greater than the diameter of the protrusion.

6. An all-solid-state battery according to claim 5, wherein an insulating sheet is provided on the surface of the can lid portion facing the bottom surface of the battery can, and the amount of protrusion of the protrusion is greater than the thickness of the insulating sheet.

7. The all-solid-state battery according to claim 6, wherein the protrusion has a protruding amount that is greater than the thickness of the insulating sheet and is 0.2 mm or less.

8. An all-solid-state battery as described in claim 1, wherein the battery molded body has a positive electrode tab connected to the positive electrode and a negative electrode tab connected to the negative electrode, the positive electrode tab is connected to the positive electrode power supply plate, and the negative electrode tab is connected to the negative electrode power supply plate.

9. The all-solid-state battery according to claim 2, wherein each of the plurality of battery molded bodies is arranged via an insulating plate.

10. A first step of compressing a positive electrode mixture, a negative electrode mixture, and a solid electrolyte in a first compression direction to form a laminate in which a positive electrode, a negative electrode, and a solid electrolyte layer interposed between the positive electrode and the negative electrode are laminated, producing a positive electrode tab connected to the positive electrode and a negative electrode tab connected to the negative electrode, and manufacturing a battery molded body by attaching the positive electrode tab to the positive electrode of the laminate and attaching the negative electrode tab to the negative electrode, a second step of manufacturing a cell assembly by attaching a positive electrode power supply plate and a negative electrode power supply plate to the positive electrode tab and the negative electrode tab attached to the battery molded body, a third step of housing the cell assembly in a bottomed cylindrical battery can with the first compression direction aligned in an axial direction intersecting with the bottom surface, and a fourth step of compressing an insulating material in a second compression direction to form an insulating portion, and integrally forming a can lid portion having the insulating portion and an electrode terminal which is a conductive material. and a fifth step of attaching the can lid portion to one end of the battery can with the second compression direction aligned with the axial direction.

11. A method for manufacturing an all-solid-state battery as described in claim 10, wherein in the second step, each of the multiple battery molded bodies is stacked along the axial direction, and a positive electrode power supply plate and a negative electrode power supply plate are attached to the positive electrode tab and the negative electrode tab attached to each of the multiple battery molded bodies.

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