All-solid-state battery production method

Abstract

Provided is a method for producing, with excellent productivity, an all-solid-state battery having a high output characteristic.　This all-solid-state battery production method is a method for producing an all-solid-state battery having at least one power generation element and an outer package, characterized in that the power generation element has a positive electrode layer, a negative electrode layer, and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer, and the production method has a power generation element heating step for heating the power generation element to 130°C or higher, a power generation element cooling step for cooling the power generation element that has undergone the power generation element heating step, and an outer package housing step for housing, in the outer package, the power generation element that has undergone the power generation element cooling step.

Description

Manufacturing method for all-solid-state batteries

[0001] The present invention relates to a method for producing an all-solid-state battery with high output characteristics with excellent productivity.

[0002] As batteries, non-aqueous electrolyte batteries such as lithium ion batteries using an organic electrolyte are widely used. However, in recent years, as the range of application fields expands, there has been a demand for higher capacity and use in high-temperature environments, which has led to an increased demand for improved safety, for example.

[0003] For these reasons, attention is being drawn to all-solid-state batteries, which can ensure excellent heat resistance by using a molded solid electrolyte instead of an organic electrolyte solution that uses an organic solvent, which is a flammable liquid.

[0004] Various studies are currently being conducted on all-solid-state batteries. For example, Patent Document 1 discloses a manufacturing method for obtaining an all-solid-state battery with high output characteristics and cycle characteristics, which includes a first step of assembling an all-solid-state battery including an electrode group having a positive electrode, a solid electrolyte layer, and a negative electrode, a second step of heating the all-solid-state battery in an uncharged state, and a third step of cooling the heated all-solid-state battery in an uncharged state. Patent Document 1 states that the manufacturing method allows the solid electrolyte particles to be appropriately and slowly blended together while in contact with or close to each other or to the active material particles, thereby allowing the solid electrolyte particles to adhere to each other or to the active material particles, thereby obtaining an all-solid-state battery with high output characteristics.

[0005] In the manufacturing method described in Patent Document 1, the all-solid-state battery is heated in an assembled state. Therefore, when the all-solid-state battery includes a component made of resin, it is desirable that the heating temperature be lower than the melting point or decomposition temperature of the resin of the component.

[0006] JP 2019-40758 A (claims, paragraphs

[0012] ,

[0045] , etc.)

[0007] However, depending on the type of resin used in the constituent members of the all-solid-state battery, the heating may need to be carried out at a very low temperature, which may result in a very limited effect on improving the output characteristics.

[0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing an all-solid-state battery with high output characteristics with excellent productivity.

[0009] The method for producing an all-solid-state battery of the present invention is a method for producing an all-solid-state battery having at least one power generating element and an exterior body, wherein the power generating element has a positive electrode layer, a negative electrode layer, and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer, and the method comprises a power generating element heating step of heating the power generating element to 130°C or higher, a power generating element cooling step of cooling the power generating element that has undergone the power generating element heating step, and an exterior body accommodating step of accommodating the power generating element that has undergone the power generating element cooling step in the exterior body.

[0010] According to the present invention, it is possible to provide a method for manufacturing an all-solid-state battery with high output characteristics with excellent productivity.

[0011] Fig. 1 is an external perspective view schematically showing an example of an all-solid-state battery manufactured by the manufacturing method of the present invention. Fig. 2 is a cross-sectional view taken along line II in Fig. 1. Fig. 3 is an exploded perspective view of the cell assembly in Fig. 2. Fig. 4 is a cross-sectional view schematically showing another example of an all-solid-state battery manufactured by the manufacturing method of the present invention.

[0012] In the method for producing an all-solid-state battery of the present invention, an all-solid-state battery is produced, which includes at least one power generation element and an exterior body, the power generation element having a positive electrode layer, a negative electrode layer, and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer, and the power generation element is heated to 130°C or higher, cooled, and then housed in the exterior body.

[0013] As described in Patent Document 1, when manufacturing an all-solid-state battery having a power generation element in which a positive electrode layer, a solid electrolyte layer, and a negative electrode layer are sequentially stacked, it is possible to improve the output characteristics of the battery by performing a heat treatment. However, if the heat treatment is performed on an all-solid-state battery in a state in which the power generation element is housed in an exterior body and assembled, and if the all-solid-state battery has resin components inside the exterior body (such as a resin housing that houses the power generation element, a resin tube that covers the power generation element, or a resin insulating member that insulates conductive components of different polarities), there is a risk of the resin melting and other deterioration. To prevent this, it is necessary to set the heat treatment temperature low, and there are cases in which the effect of improving the output characteristics by the heat treatment cannot be sufficiently ensured.

[0014] However, in the manufacturing method of the present invention, since the power generation element is heated before being housed in the outer casing, cooled, and then housed in the outer casing to manufacture an all-solid-state battery, even if the all-solid-state battery has a resin component inside, it is possible to avoid producing a battery with poor characteristics that makes it unusable due to the influence of the resin component caused by the heat treatment of the power generation element. Thus, according to the manufacturing method of the present invention, the heat treatment of the power generation element can be carried out at a high temperature of 130°C or higher, and therefore all-solid-state batteries with higher output characteristics can be manufactured with excellent productivity.

[0015] An example of an all-solid-state battery manufactured by the manufacturing method of the present invention will be described below with reference to the drawings. Fig. 1 is an external perspective view of the all-solid-state battery, and Fig. 2 is a cross-sectional view taken along line II of Fig. 1.

[0016] The all-solid-state battery 1 shown in FIGS. 1 and 2 includes a cell assembly 21 having an electrode body 20 formed by stacking six power generation elements 20a, 20b, 20c, 20d, 20e, and 20f, housed in an exterior body made up of a cylindrical exterior can 10 with a bottom and a lid 50.

[0017] The outer can 10 has a bottom surface 101 and a side surface 102. A plurality of recesses 103 extending from the lower end toward the upper direction in the figure are formed on the outer peripheral wall surface of the side surface 102 by, for example, pressing. This increases the rigidity of the outer can 10, and therefore prevents the outer can 10 from being easily crushed or damaged when a strong external force is applied to the outer can 10.

[0018] Furthermore, by forming the recess 103, a protrusion that protrudes toward the inside of the exterior can 10 is formed on the inner peripheral wall surface of the side surface 102 of the exterior can 10 at the position where the recess 103 is formed. This protrusion comes into contact with the side surface of the cell assembly 21 (the side surface of the electrode body 20) when the cell assembly 21 having the electrode body 20 is housed inside the exterior can 10. This prevents the cell assembly 21 (the electrode body 20 housed therein) from vibrating inside the exterior can 10.

[0019] The recess 103 does not have to be formed in the exterior can 10. In this case, for example, the cell assembly 21 (electrode body 20) and the inner peripheral wall surface of the side surface 102 of the exterior can 10 can be fixed by adhesive. Also, a sealing member made of a non-conductive material such as resin may be disposed in the gap between the cell assembly 21 (electrode body 20) and the inner peripheral wall surface of the side surface 102 of the exterior can 10 to fill the gap.

[0020] The exterior can 10 can be made of aluminum, stainless steel, nickel alloy, or the like.

[0021] The lid 50 has a metal terminal 52 attached to a metal body 51 via an insulator 53 made of resin (e.g., polypropylene), glass hermetic, ceramic hermetic, or the like. When using an electrolyte that decomposes due to atmospheric moisture, such as a sulfide or hydride, as the solid electrolyte, it is desirable to use a more airtight glass hermetic or ceramic hermetic. The lid 50 is inserted into the opening of the outer can 10, and the opening of the outer can 10 is sealed by welding the joint between the two, thereby sealing the interior of the battery. An insulating sheet 54 is attached to the underside of the body 51 of the lid 50 (the surface facing the inside of the battery). A connection lead 60 is attached to the surface of the terminal 52 facing the inside of the battery for electrically connecting the electrode body 20 and the terminal 52.

[0022] The main body 51 and terminals 52 of the lid 50 can be made of aluminum, stainless steel, nickel alloy, or the like.

[0023] The cell assembly 21 includes an electrode body 20 , a holder 22 , a positive electrode lead 30 , and a negative electrode lead 40 .

[0024] 3 shows an exploded perspective view of the cell assembly 21. In the cell assembly 21, six power generation elements 20a, 20b, 20c, 20d, 20e, and 20f and insulating plates 210a, 210b, 210c, 210d, and 210e interposed therebetween are arranged in the vertical direction in the figure to form the electrode body 20. In this manner, a plurality of power generation elements (two or more) can be accommodated in the cylindrical outer can, and the size of the all-solid-state battery can be increased.

[0025] Each of the individual power generating elements 20a, 20b, 20c, 20d, 20e, and 20f of the electrode assembly 20 is configured by sequentially stacking a positive electrode layer 201, a solid electrolyte layer 203, and a negative electrode layer 202. These power generating elements 20a, 20b, 20c, 20d, 20e, and 20f are stacked in the vertical direction in the figure and connected in parallel to each other as described below to configure the electrode assembly 20. Note that the all-solid-state battery is not limited to one having six power generating elements, and it is sufficient that the battery has at least one power generating element.

[0026] The electrode body 20 is formed by stacking each power generating element 20a, 20b, 20c, 20d, 20e, and 20f so that the positive electrode layer and negative electrode layer of adjacent power generating elements face each other with insulating plates 210a, 210b, 210c, 210d, and 210e interposed therebetween.

[0027] A positive electrode tab 204 and a negative electrode tab 205 can be attached to the positive electrode layer 201 and the negative electrode layer 202 of each of the power generation elements 20a, 20b, 20c, 20d, 20e, and 20f, respectively. Then, by connecting the positive electrode tabs 204 of all the power generation elements to the positive electrode lead 30 and the negative electrode tabs 205 of all the power generation elements to the negative electrode lead 40 by welding or the like, each of the power generation elements 20a, 20b, 20c, 20d, 20e, and 20f in the electrode body 20 can be connected in parallel.

[0028] Although not shown in FIG. 2 , the positive electrode tab 204 can be attached by, for example, providing a current collector 201 a on the positive electrode layer 201 as shown in FIG. 3 and welding the current collector 201 a to the positive electrode tab 204, and the negative electrode tab 205 can also be attached by providing a current collector on the negative electrode layer and welding the current collector to the negative electrode tab 205.

[0029] The electrode body 20 is held from below, the sides, and above by a holder 22. The holder 22 is composed of a first holding portion 23 that holds the bottom and sides of the electrode body 20, and a second holding portion 24 that is positioned above the electrode body 20. The first holding portion 23 has a bottom holding portion 231 and multiple side holding portions 232 (four in FIG. 3 ) that extend upward in the figure from the bottom holding portion 231. A hook-shaped bent portion 232 a is provided above the side holding portion 232.

[0030] The holder 22 is made of a resin, such as polypropylene, that has insulating properties, bending resistance, and low water absorption.

[0031] When the electrode body 20 is held by the holder 22, for example, the electrode body 20 is placed on the bottom holding portion 231 of the first holding portion 23 via a sheet 233 made of a resin such as a silicone material or various elastomers as an insulating member, and the second holding portion 24 is then placed above the electrode body 20. The bent portion 232a at the tip of the side holding portion 232 of the first holding portion 23 is fitted into a fixing portion provided on the second holding portion 24, thereby fixing the side holding portion 232 and the second holding portion 24. In this way, the electrode body 20 is held within the holder 22 formed by the first holding portion 23 and the second holding portion 24.

[0032] The sheet 233 does not have to be used, but by using it, the electrode body 20 can be easily rotated within the holder 22, which makes it easier to align the electrodes, for example, when welding the positive electrode tab 204 to the positive electrode lead 30 or welding the negative electrode tab 205 to the negative electrode lead 40.

[0033] The side surfaces of the cell assembly 21 can be covered with a heat-shrinkable tube 213 (a resin insulating member) made of insulating resin such as polyethylene or various elastomers. This heat-shrinkable tube 213 can insulate the electrode body 20 from the metal outer can 10, for example.

[0034] In addition, the side surfaces and portions of the upper and lower surfaces of each power generating element 20a, 20b, 20c, 20d, 20e, and 20f can also be covered with a heat-shrinkable tube 212 (a resin insulating member) made of an insulating resin such as polyethylene or various elastomers.

[0035] In addition, even in the cylindrical all-solid-state battery as shown in FIGS. 1 and 2, two or more power generating elements may be connected in series as shown in FIG. 4 described later.

[0036] When the cell assembly 21 is enclosed in the exterior body, first, a buffer sheet 104 is placed on the inner bottom surface of the exterior can 10 as needed, and then the cell assembly 21 is placed on top of that. The negative electrode lead 40 of the cell assembly 21 is connected to the inner surface of the exterior can 10 by, for example, welding, etc. This allows the exterior can 10 to also serve as the negative electrode terminal.

[0037] Furthermore, the positive electrode lead 30 of the cell assembly 21 is connected to the connection lead 60 of the lid 50 by welding or the like. This allows the terminal 52 to function as a positive electrode terminal. Thereafter, the lid 50 is placed over the open end of the outer can 10 and sealed. In this manner, the all-solid-state battery 1 can be obtained.

[0038] A part of the positive electrode lead 30 (for example, a part located on the upper surface side of the cell assembly 21) is exposed and not covered with the heat shrink tube 213. Therefore, in order to prevent contact between the exposed part of the positive electrode lead 30 and the outer casing 10, the exposed part of the positive electrode lead 30 may be covered with an insulating seal 206 that is an insulating member (for example, an insulating member made of resin).

[0039] Although FIG. 2 shows an all-solid-state battery in an embodiment in which the outer can 10 also functions as a negative electrode terminal and the terminal 52 functions as a positive electrode terminal, if necessary, the outer can 10 may also function as a positive electrode terminal and the terminal 52 may function as a negative electrode terminal.

[0040] 4 is a cross-sectional view schematically illustrating another example of an all-solid-state battery manufactured by the manufacturing method of the present invention. The all-solid-state battery 2 shown in Fig. 4 has a coin-shaped (also called button-shaped) exterior body made up of an exterior can 400, a sealing can 401, and a gasket 402, and has two power generating elements 20g and 20h enclosed therein, each of which is formed by sequentially stacking a positive electrode layer 201, a solid electrolyte layer 203, and a negative electrode layer 202.

[0041] In the all-solid-state battery 2, the sealing can 401 is fitted into the opening of the outer can 400 via a gasket 402, and the open end of the outer can 400 is tightened inward, whereby the gasket 402 comes into contact with the sealing can 401, thereby sealing the opening of the outer can 400 and forming an airtight structure inside the battery.

[0042] The power generating element 20g and the power generating element 20h included in the all-solid-state battery 2 are stacked such that the negative electrode layer 202 of the power generating element 20g and the positive electrode layer 201 of the power generating element 20h face each other via the current collector 300. That is, the power generating element 20g and the power generating element 20h are connected in series.

[0043] The side surfaces of the power generating element 20g and the power generating element 20h can be covered with a heat-shrinkable tube 213 made of insulating resin such as polyethylene or various elastomers.

[0044] The outer can 400 and the positive electrode layer 201 of the power generating element 20g are electrically connected via a current collector 301, and the outer can 400 also serves as a positive electrode terminal. The sealing can 401 and the negative electrode layer 202 of the power generating element 20h are electrically connected via a current collector 302, and the sealing can 401 also serves as a negative electrode terminal.

[0045] In addition, in a coin-type all-solid-state battery, if necessary, the outer can can also serve as a negative electrode terminal, and the sealed can can also serve as a positive electrode terminal. Furthermore, in a coin-type all-solid-state battery, the number of power generation elements is not limited to two, but may be one or more. Furthermore, in a coin-type all-solid-state battery, two or more power generation elements may be connected in parallel, as in the all-solid-state battery shown in FIG. 2 .

[0046] The all-solid-state batteries manufactured by the manufacturing method of the present invention include primary batteries and secondary batteries. The present invention will be described in detail below.

[0047] <Power Generation Element> The power generation element of the all-solid-state battery has a positive electrode layer, a negative electrode layer, and a solid electrolyte layer interposed between them.

[0048] The positive electrode layer of the power generating element can be formed, for example, by molding a positive electrode mixture containing a positive electrode active material and the like.

[0049] When the all-solid-state battery is a primary battery, the positive electrode active material can be the same as the positive electrode active material used in known non-aqueous electrolyte primary batteries. Specifically, for example, manganese dioxide, lithium-containing manganese oxide (e.g., LiMn ３ O ６ or a composite oxide having the same crystal structure as manganese dioxide (e.g., β-type, γ-type, or a mixed structure of β-type and γ-type) and containing 3.5% by mass or less, preferably 2% by mass or less, more preferably 1.5% by mass or less, particularly preferably 1% by mass or less of Li, ａ Ti ５／３ O ４(4 / 3≦a<7 / 3) and other lithium-containing composite oxides; vanadium oxide; niobium oxide; titanium oxide; sulfides such as iron disulfide; graphite fluoride; Ag ２ Silver sulfides such as S; NiO ２ Nickel oxides such as:

[0050] When the all-solid-state battery is a secondary battery, the positive electrode active material is not particularly limited as long as it is a positive electrode active material used in known non-aqueous electrolyte secondary batteries, that is, an active material capable of absorbing and releasing Li ions. Specific examples of the positive electrode active material include LiM ｒ Mn ２－ｒ O ４ (wherein M is at least one element selected from the group consisting of Li, Na, K, B, Mg, Ca, Sr, Ba, Ti, V, Cr, Zr, Fe, Co, Ni, Cu, Zn, Al, Sn, Sb, In, Nb, Ta, Mo, W, Y, Ru, and Rh, and 0≦r≦1), a spinel-type lithium manganese composite oxide represented by Li ｒ Mn （１－ｓ－ｒ） Ni ｓ M ｔ O （２－ｕ） F ｖ (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≦r≦1.2, 0<s<0.5, 0≦t≦0.5, u+v<1, −0.1≦u≦0.2, 0≦v≦0.1), a layered compound represented by １－ｒ M ｒ O ２ (wherein M is at least one element selected from the group consisting of Al, Mg, Ti, V, Cr, Zr, Fe, Ni, Cu, Zn, Ga, Ge, Nb, Mo, Sn, Sb, and Ba, and 0≦r≦0.5), lithium cobalt composite oxide represented by LiNi １－ｒ M ｒ 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≦r≦0.5), a lithium nickel composite oxide represented by Li １＋ｓ M１－ｒ N ｒ P.O. ４ F ｓ (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, V, and Ba, and 0≦r≦0.5, 0≦s≦1), Li ２ M １－ｒ N ｒ P ２ O ７ (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, V, and Ba, and 0≦r≦0.5), and the like. Among these, only one type may be used, or two or more types may be used in combination.

[0051] When the all-solid-state battery is a secondary battery, the average particle diameter of the positive electrode active material is preferably 0.1 μm or more, more preferably 0.5 μm or more, and preferably 25 μm or less, more preferably 10 μm or less, from the viewpoint of reducing side reactions that cause battery capacity degradation and increasing the density of the positive electrode. The positive electrode active material may be primary particles or secondary particles formed by aggregation of primary particles. When the positive electrode layer contains a solid electrolyte, using a positive electrode active material with an average particle diameter in the above range allows for a large interface with the solid electrolyte, thereby further improving the load characteristics of the battery.

[0052] The average particle diameter of the positive electrode active material and the average particle diameter of other particles (such as solid electrolytes) referred to in this specification are determined by a particle size distribution measuring device (such as a Microtrac particle size distribution measuring device "HRA9320" manufactured by Nikkiso Co., Ltd.) and are the 50% diameter value (D) in the volume-based integrated fraction when determining the integrated volume from particles with small particle sizes. ５０ ) means

[0053] When the positive electrode layer contains a solid electrolyte, the positive electrode active material preferably has a reaction suppression layer on its surface to suppress reaction with the solid electrolyte contained in the positive electrode layer.

[0054] If the positive electrode active material and the solid electrolyte come into direct contact in the positive electrode layer, the solid electrolyte may oxidize to form a resistance layer, which may reduce ionic conductivity in the layer. 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 the reduction in ionic conductivity in the positive electrode layer due to oxidation of the solid electrolyte.

[0055] 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, Zr, Ta, and W, 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 , Li ２ WO ４ 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

[0056] The reaction suppression layer is preferably present on the surface in an amount of 0.1 to 2.0 parts 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.

[0057] 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, PVD method, and ALD method.

[0058] The content of the positive electrode active material in the positive electrode layer is preferably 20 to 95 mass %.

[0059] Examples of conductive additives for the positive electrode include carbon materials such as carbon black (thermal black, furnace black, channel black, ketjen black, acetylene black, etc.), graphite (natural graphite, artificial graphite), graphene, vapor-grown carbon fiber, carbon nanofiber, and carbon nanotube; powders of Cu, Ni, Al, Au, and Pd alone or alloys thereof, or porous bodies thereof; and these may be used alone or in combination of two or more. The content of the conductive additive in the positive electrode layer is preferably 0.1 to 15% by mass.

[0060] The positive electrode layer may contain a solid electrolyte. The solid electrolyte used in the positive electrode layer is not particularly limited as long as it has Li ion conductivity, and examples thereof include sulfide-based solid electrolytes, hydride-based solid electrolytes, halide-based solid electrolytes, and oxide-based solid electrolytes.

[0061] The sulfide-based solid electrolyte is Li ２ S-P ２ S ５ , Li ２ S-SiS ２ , Li ２ S-P ２ S ５ -GeS ２ , Li ２ S-B ２ S ３ In addition to particles of glass, thio-LISICON type particles [Li １０ GeP ２ S １２ , Li ９．５４ Si １．７４ P １．４４ S １１．７ Cl ０．３ Li12-12a-b+c+6d-eM, etc. １３＋ａ－ｂ－ｃ－ｄ M ２ ｂ M ３ ｃ M ４ ｄ M ５ １２－ｅ X ｅ (However, M １ is Si, Ge or Sn, M ２ is P or V, M ３ is Al, Ga, Y or Sb, M ４ is Zn, Ca, or Ba, M ５ is either S or S and O, and X is F, Cl, Br or I, 0≦a<3, 0≦b+c+d≦3, 0≦e≦3], or argyrodite type [Li ６ P.S. ５ Li, such as Cl ７－ｋ P.S. ６－ｋ X ｋ (wherein X represents one or more halogen elements, and 0.2<k<2.0), Li ７－ｆ＋ｇ P.S. ６－ｆ Cl ｆ＋ｇ (wherein 0.05≦g≦0.9, −3.0f+1.8≦g≦−3.0f+5.7), Li ７－ｈ P.S. ６－ｈ Cl ｉ Br ｊ (where h=i+j, 0<h≦1.8, 0.1≦i / j≦10.0) can also be used.

[0062] 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, RbF, RbCl, etc.), cesium halides (CsI, CsBr, CsF, CsCl, etc.), lithium amide, rubidium amide, and cesium amide.

[0063] Examples of halide-based solid electrolytes include monoclinic LiAlCl ４ , defect spinel type or layer structure LiInBr ４ , monoclinic Li ６－３ｍ Y ｍ X ６ (wherein 0 < m < 2 and X = Cl or Br), and other known compounds described in, for example, WO 2020 / 070958 and WO 2020 / 070955 can also be used.

[0064] Examples of oxide-based solid electrolytes include Li ２ O-Al ２ O ３ -SiO ２ -P ２ O ５ -TiO ２ Li-based glass ceramics ２ O-Al ２ O ３ -SiO ２ -P ２ O ５ -GeO ２ Lithium-ion-based glass ceramics, garnet-type ７ La ３ Zr ２ O １２ , NASICON type Li １＋Ｏ Al １＋Ｏ Ti ２－Ｏ (P.O. ４ ) ３ , Li １＋ｐ Al １＋ｐ Ge ２－ｐ (P.O. ４ ) ３ , perovskite-type Li ３ｑ La ２／３－ｑ TiO ３ Examples include:

[0065] Among these solid electrolytes, sulfide-based solid electrolytes are preferred because of their high Li ion conductivity, sulfide-based solid electrolytes containing Li and P are more preferred, and argyrodite-type sulfide-based solid electrolytes are even more preferred because of their particularly high Li ion conductivity and high chemical stability.

[0066] The content of the solid electrolyte in the positive electrode layer is preferably 4 to 80 mass %.

[0067] The positive electrode layer may contain a binder, or may not contain a binder if good moldability can be ensured without using a binder, such as in the case of a positive electrode in which a sulfide-based solid electrolyte is contained and powder of the positive electrode mixture is charged into a molding die and compacted.

[0068] Examples of the binder contained in the positive electrode layer include fluororesins such as PVDF.

[0069] When a binder is required in the positive electrode layer, the content thereof is preferably 15% by mass or less, and preferably 0.5% by mass or more. On the other hand, when a binder is not required in the positive electrode layer from the viewpoint of formability, the content thereof is preferably 0.5% by mass or less, more preferably 0.3% by mass or less, and even more preferably 0% by mass (i.e., no binder is contained).

[0070] The positive electrode layer may have a current collector. Examples of the current collector for the positive electrode layer include metal foils such as aluminum and stainless steel; sheet-like conductive porous substrates such as punched metal, mesh, expanded metal, and foamed metal; and carbon sheets. As the sheet-like conductive porous substrate, it is preferable to use a foamed metal porous body. A specific example of a foamed metal porous body is "Celmet (registered trademark)" from Sumitomo Electric Industries, Ltd.

[0071] The positive electrode layer 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.

[0072] In the case of a positive electrode layer having a current collector, it can be formed by, for example, pressing the current collector onto the pressure-molded body of the positive electrode mixture obtained as described above.

[0073] The thickness of the positive electrode layer is usually 50 μm or more, but from the viewpoint of increasing the capacity of the battery, it is preferably 200 μm or more, and is usually 2000 μm or less.

[0074] The thickness of the current collector for the positive electrode layer is preferably 0.01 to 0.1 mm.

[0075] The negative electrode layer of the power generating element can be formed, for example, by molding a negative electrode mixture containing a negative electrode active material and the like.

[0076] When the all-solid-state battery is a primary battery, examples of the negative electrode active material include metallic lithium and lithium alloys (lithium-aluminum alloys, lithium-indium alloys, etc.).

[0077] When the all-solid-state battery is a secondary battery, the negative electrode active material may be, for example, one or a mixture of two or more carbonaceous 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. Also usable as the negative electrode active material are simple substances, compounds, and alloys thereof containing elements such as Si, Sn, Ge, Bi, Sb, and In; compounds capable of charging and discharging at low voltages close to those of lithium metal, such as lithium-containing nitrides or lithium-containing oxides; lithium metal; and lithium / aluminum alloys. For example, Li ４ Ti ５ O １２ and TiO ２ , NbO ２．５－δ (0≦δ≦0.5), MoO ３－δ (0≦δ≦1), WO ３－δ (0≦δ≦1), TiNb ２ O ７ Metal oxides such as WS ２ , MoS ２ or a mixture of two or more of these metal sulfides can also be used as the negative electrode active material.

[0078] The content of the negative electrode active material in the negative electrode layer is preferably 50 to 95 mass %.

[0079] The negative electrode layer can contain a solid electrolyte. The solid electrolyte contained in the negative electrode layer can be one or more of the sulfide-based solid electrolytes, hydride-based solid electrolytes, and oxide-based solid electrolytes previously exemplified as the solid electrolytes that can be contained in the positive electrode layer. Among the solid electrolytes exemplified above, sulfide-based solid electrolytes are more preferably used because they have high Li ion conductivity and also have the function of improving the formability of the negative electrode layer, and argyrodite-type sulfide-based solid electrolytes are even more preferably used.

[0080] The content of the solid electrolyte in the negative electrode layer is preferably 4 to 70 mass %.

[0081] The negative electrode layer may contain a conductive additive. Specific examples include carbon materials such as graphite (natural graphite, artificial graphite), graphene, carbon black, vapor-grown carbon fiber, carbon nanofiber, and carbon nanotube. The content of the conductive additive in the negative electrode layer is preferably 1 to 10 mass %.

[0082] The negative electrode layer may or may not contain a binder. Specific examples thereof include the same binders as those exemplified above as binders that can be contained in the positive electrode layer. For example, when the negative electrode layer contains a sulfide-based solid electrolyte, if good moldability can be ensured in forming the negative electrode layer without using a binder, the negative electrode layer may not contain a binder.

[0083] When a binder is required in the negative electrode layer, the content is preferably 15% by mass or less, and preferably 0.5% by mass or more. On the other hand, when good moldability can be obtained without the binder in the negative electrode layer, the content is preferably 0.5% by mass or less, more preferably 0.3% by mass or less, and even more preferably 0% by mass (i.e., no binder is contained).

[0084] The negative electrode layer may have a current collector. Examples of the current collector for the negative electrode layer include sheet-like conductive porous substrates such as copper or nickel foil, punched metal, mesh, expanded metal, and foamed metal; carbon sheets; and the like. As the sheet-like conductive porous substrate, it is preferable to use a foamed metal porous body. A specific example of a foamed metal porous body is "Celmet (registered trademark)" by Sumitomo Electric Industries, Ltd.

[0085] The negative electrode layer can be formed, for example, by compressing a negative electrode mixture prepared by mixing a negative electrode active material, a conductive additive, a solid electrolyte, and, if necessary, a binder, by pressure molding or the like.

[0086] In the case of a negative electrode layer having a current collector, it can be formed by, for example, pressing the current collector onto the pressure-molded body of the negative electrode mixture obtained as described above.

[0087] The thickness of the negative electrode layer is usually 100 μm or more, but is preferably 200 μm or more from the viewpoint of increasing the capacity of the battery, and is usually 3000 μm or less.

[0088] The thickness of the current collector for the negative electrode layer is preferably 0.01 to 0.1 mm.

[0089] The solid electrolyte layer of the power generating element can use one or more of the sulfide-based solid electrolytes, hydride-based solid electrolytes, and oxide-based solid electrolytes listed above as examples of solid electrolytes that can be contained in the positive electrode layer. Among the above-listed solid electrolytes, it is more preferable to use a sulfide-based solid electrolyte, and it is even more preferable to use an argyrodite-type sulfide-based solid electrolyte, in order to improve battery characteristics.

[0090] The solid electrolyte layer can be formed by a method of compressing a solid electrolyte by pressure molding or the like; a method of applying a solid electrolyte layer-forming composition prepared by dispersing a solid electrolyte in a solvent onto a substrate, a positive electrode, or a negative electrode, drying the composition, and, if necessary, performing pressure molding such as pressing.

[0091] The solid electrolyte layer may also have a porous body such as a resin nonwoven fabric as a support.

[0092] It is preferable to select a solvent for the solid electrolyte layer-forming composition that is less likely to deteriorate the solid electrolyte. 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 nonpolar aprotic solvent, such as hydrocarbon solvents such as hexane, heptane, octane, nonane, decane, decalin, toluene, and xylene. It is particularly preferable to use an ultra-dehydrated solvent with a water content of 0.001% by mass (10 ppm) or less. 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 nonaqueous organic solvents such as dichloromethane and diethyl ether can also be used.

[0093] The thickness of the solid electrolyte layer is preferably 10 to 500 μm.

[0094] The power generation element is formed by sequentially stacking a positive electrode layer, a solid electrolyte layer, and a negative electrode layer. To obtain the power generation element, for example, a positive electrode layer (or a negative electrode layer) may be formed in advance by pressure molding, and the solid electrolyte layer and the negative electrode layer (or a positive electrode layer) may be sequentially pressure molded using the positive electrode layer (or a negative electrode layer) as a base material, or a positive electrode layer may be formed by pressure molding on one side of a solid electrolyte layer previously formed by pressure molding, and the negative electrode layer may be formed by pressure molding on the other side of the solid electrolyte layer.

[0095] The shape of the power generating element in plan view is not particularly limited, and may be a circle, an ellipse, a polygon such as a square, or the like.

[0096] The all-solid-state battery may have only one power generating element or may have multiple (two, three, four, etc.) power generating elements. There is no particular upper limit on the number of power generating elements that the all-solid-state battery has, and the number may be 10, 20, 100, 1000, or more depending on the properties required of the all-solid-state battery.

[0097] In an all-solid-state battery having a plurality of (two or more) power generating elements, for example, the plurality of power generating elements are connected in series or in parallel to each other to form an electrode body for use in the all-solid-state battery. In this case, depending on the shape of the exterior body of the all-solid-state battery, for example, as shown in Fig. 1, the plurality of power generating elements may be stacked and used in the battery as an electrode body, or, for example, the plurality of power generating elements may be arranged in a planar manner and used in the battery as an electrode body.

[0098] For example, when a plurality of power generation elements are stacked to form an electrode body for use in an all-solid-state battery, in order to connect these power generation elements in parallel, for example, as shown in FIG. 2 , in addition to a method of stacking the power generation elements via an insulating plate, a method of stacking adjacent power generation elements so that their electrode layers of the same polarity (positive electrode layer or negative electrode layer) face each other can be employed.

[0099] Furthermore, when a plurality of power generation elements are stacked to form an electrode body for use in an all-solid-state battery, and when these power generation elements are connected in series, for example, a method can be employed in which adjacent power generation elements are stacked such that their electrode layers of opposite polarities face each other.

[0100] When forming an electrode assembly by stacking power generating elements, whether the power generating elements are connected in parallel or in series, a conductive connection terminal may be interposed between opposing electrode layers to electrically connect them. The connection terminal that electrically connects the electrode layers may be fixed to either one of the opposing electrode layers, or may not be fixed to either electrode layer. When fixing the connection terminal to the electrode layer, for example, the connection terminal may be welded to the metal current collector of an electrode layer having the metal current collector.

[0101] <Exterior Body> The exterior body of the all-solid-state battery is not particularly limited, and examples that can be used include a battery container having a concave container (exterior container) and a sealing body (lid); a battery container having a shape (such as a coin shape or a button shape) that has a metal exterior can and a metal sealing body; a battery container having a cylindrical, bottomed metal exterior can (such as a cylindrical or rectangular shape) and a lid as shown in FIG. 1; and a battery container made of a laminate film exterior body made of a metal laminate film such as an aluminum laminate film.

[0102] <Method for manufacturing all-solid-state battery> When manufacturing an all-solid-state battery, first, a power generation element formed by laminating a positive electrode layer, a solid electrolyte layer, and a negative electrode layer is subjected to a heat treatment (power generation element heat treatment step). This heat treatment makes it possible to improve the output characteristics of the manufactured all-solid-state battery. The power generation element subjected to the power generation element heat treatment step may be in an uncharged state or a charged state, but is preferably in an uncharged state because this improves the characteristics of the resulting all-solid-state battery.

[0103] From the viewpoint of improving the output characteristics of the all-solid-state battery after manufacture, the heat treatment temperature is 130°C or higher, and more preferably 150°C or higher. The upper limit of the heat treatment temperature is not particularly limited as long as it is within a range in which deterioration of the constituent materials of the power generation element can be suppressed, but is preferably, for example, 200°C and 180°C or lower. The heat treatment time can be, for example, 60 to 1440 minutes, and is preferably 100 minutes or higher, preferably 120 minutes or higher, and preferably 1000 minutes or lower, and preferably 500 minutes or lower. The heat treatment time can be adjusted within a range in which deterioration of the heat treatment temperature and the constituent materials of the power generation element can be suppressed. In this specification, the heat treatment time refers to the time during which a predetermined heat treatment temperature is maintained.

[0104] There are no particular limitations on the method for heat-treating the power generation element, and commonly used devices such as a thermostatic bath or electric furnace can be used. There are also no particular limitations on the atmosphere during the heat treatment, and the heat treatment can be carried out in air, in an inert gas such as nitrogen gas, or in a vacuum. The power generation element may also be heat-treated without applying pressure using a press or the like.

[0105] After the power generating element heat treatment step, the power generating element is cooled in the next power generating element cooling step. The temperature of the power generating element after cooling is, for example, 40°C or less, preferably 35°C or less, and may be 0°C or more, and 15°C or more. There are no particular restrictions on the cooling method, and for example, the power generating element may be left in a room temperature environment. Furthermore, the power generating element after the heat treatment may be cooled by leaving it in the thermostatic bath or electric furnace in which the heat treatment was performed, or may be cooled using a thermostatic bath set to a temperature lower than the heat treatment temperature.

[0106] After the power generation element cooling step, the power generation element is enclosed in an outer casing either as it is or as an electrode body made up of a combination of multiple power generation elements as needed to form an all-solid-state battery (exterior casing accommodation step). When forming a cell assembly using a holder such as that shown in Figures 2 and 3, a cell assembly is formed using a single power generation element or an electrode body (power generation element) made up of multiple stacked elements, and then enclosed in an outer casing.

[0107] The power generating element that has undergone the power generating element cooling step may be subjected to the exterior housing step after current collecting members such as the positive electrode tab 204, the negative electrode tab 205, the positive electrode lead 30, and the negative electrode lead 40 are attached and the power generating element and these current collecting members are connected to each other. When the power generating element to be housed in the exterior housing is, for example, a single power generating element, or a plurality of power generating elements in which the electrode layers are connected to each other directly or via current collectors, and the interior of the exterior housing has a structure that allows electrical connection between the electrode layers of the power generating element and the positive electrode terminal or negative electrode terminal of the exterior housing, the current collecting members do not need to be connected to the power generating element.

[0108] The cell assembly is manufactured by attaching a positive electrode tab 204 and a negative electrode tab 205 to the power generation element, and by attaching a positive electrode lead 30 and a negative electrode lead 40 to a plurality of power generation elements.

[0109] Furthermore, the power generating element (at least one power generating element) that has undergone the power generating element cooling step may be covered with a resin insulating member before being subjected to the exterior housing step. Examples of cases in which the power generating element is covered with a resin insulating member include, as shown in Fig. 2, inserting the power generating element into a heat shrink tube 212 and shrinking it by heating to cover the side surfaces and parts of the upper and lower surfaces of the power generating element, and inserting the cell assembly 21 into a heat shrink tube 213 and shrinking it by heating to cover at least a part of the cell assembly.

[0110] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples.

[0111] (Example 1) Lithium titanate (Li) having an average particle size of 2 μm ４ Ti ５ O １２, negative electrode active material) and a sulfide-based solid electrolyte (Li ６ P.S. ５ Cl) and graphene (conductive additive) were mixed in a mass ratio of 50:41:9 to prepare a negative electrode mixture.

[0112] In addition, LiNbO ３ LiCoO having an average particle size of 5 μm on which a coating layer of ２ (positive electrode active material) and a sulfide-based solid electrolyte (Li ６ P.S. ５ Cl) and graphene were mixed in a mass ratio of 65:30.7:4.3 to prepare a positive electrode mixture.

[0113] Next, a sulfide-based solid electrolyte (Li ６ P.S. ５ A powder of HCl) was placed in a powder molding die and pressure-molded using a press at a surface pressure of 70 MPa to form a provisionally molded layer of the solid electrolyte layer. Furthermore, the negative electrode mixture was placed on the upper surface of the provisionally molded layer of the solid electrolyte layer and pressure-molded at a surface pressure of 50 MPa to form a provisionally molded layer of the negative electrode layer on the provisionally molded layer of the solid electrolyte layer.

[0114] Furthermore, a nickel foamed metal porous body (nickel "Celmet" (registered trademark)) manufactured by Sumitomo Electric Industries, Ltd. cut into a circle (thickness: 1.2 mm, porosity: 98%) was placed on the provisionally molded layer of the negative electrode layer, and pressure molding was performed at a surface pressure of 300 MPa to form an integrated body of the provisionally molded body of the solid electrolyte layer, the provisionally molded layer of the negative electrode layer, and the porous metal substrate (current collector) for the negative electrode.

[0115] Furthermore, after the mold was turned upside down, the positive electrode mixture was placed on the upper surface of the provisionally molded layer of the solid electrolyte in the mold (the side opposite to the surface having the provisionally molded layer of the negative electrode mixture), and molding was performed with a surface pressure of 50 MPa, thereby forming a provisionally molded layer of the positive electrode on the provisionally molded layer of the solid electrolyte.

[0116] Next, a cut piece of the same nickel foamed porous metal body used for the negative electrode was placed on the provisionally molded positive electrode layer formed on the provisionally molded solid electrolyte layer, and pressure molding was performed at a surface pressure of 1400 MPa to obtain a power generation element including a positive electrode layer (0.8 mm thick) having a porous metal substrate as a current collector, a solid electrolyte layer (0.35 mm thick), and a negative electrode layer (1.4 mm thick) having a porous metal substrate as a current collector. In addition, a nickel alloy positive electrode tab was attached to the porous metal substrate of the positive electrode layer, and a nickel alloy negative electrode tab was attached to the porous metal substrate of the negative electrode layer.

[0117] The power generating element obtained as described above was subjected to heat treatment by being held in a thermostatic chamber adjusted to 150° C. for 180 minutes, and then taken out and left to cool to room temperature.

[0118] Six power generation elements that had been subjected to heat treatment and then cooled were used and stacked as shown in Fig. 3. The positive electrode tab of each power generation element was welded to the positive electrode lead, the negative electrode tab to the negative electrode lead, and the elements were held in a holder to form a cell assembly having an electrode body in which six power generation elements were connected in parallel. The sides of this cell assembly were then covered with polyethylene heat-shrink tubing, and the assembly was placed in a cylindrical outer can with a bottom. The opening of the outer can was sealed with a lid, and an all-solid-state secondary battery with the same cross-sectional structure as that shown in Fig. 2 was obtained.

[0119] Examples 2 to 6 All-solid-state secondary batteries were manufactured in the same manner as in Example 1, except that the temperature and holding time of the heat treatment applied to the power generating element were changed to the conditions shown in Table 1.

[0120] Comparative Example 1 Six power generation elements obtained in the same manner as in Example 1 except that no heat treatment was performed were used to form a cell assembly in the same manner as in Example 1, the sides of the cell assembly were covered with heat-shrinkable tubing, and the cell assembly was then housed in a cylindrical outer can with a bottom. The opening of the outer can was sealed with a lid, and the cell assembly was then subjected to heat treatment by being held in a thermostatic chamber adjusted to 150°C for 180 minutes, thereby producing an all-solid-state secondary battery.

[0121] Comparative Example 2 An all-solid-state secondary battery was manufactured in the same manner as in Comparative Example 1, except that the heat treatment after welding the lid to the open end of the outer can was carried out at 110°C.

[0122] Comparative Example 3 An all-solid-state secondary battery was manufactured in the same manner as in Comparative Example 2, except that the holding time for the heat treatment after welding the lid to the open end of the outer can was set to 1440 minutes.

[0123] The all-solid-state secondary batteries of the Examples and Comparative Examples prepared as described above were evaluated as follows.

[0124] (1 C Load Characteristics) The all-solid-state secondary batteries of the Examples and Comparative Examples were each subjected to constant current charging at a current value equivalent to 0.2 C until the voltage reached 2.6 V, followed by constant voltage charging at a voltage of 2.6 V until the current value reached 0.01 C, and then constant current discharging at a current value equivalent to 0.1 C until the voltage reached 1.0 V. The discharge capacity at this time was designated the 0.1 C discharge capacity of each all-solid-state secondary battery. Next, charging was performed under the same charging conditions as above, followed by constant current discharging at a current value equivalent to 1 C until the voltage reached 1.0 V, and the discharge capacity at this time was designated the 1 C discharge capacity. The 1 C discharge capacity measured as above was divided by the 0.1 C discharge capacity and expressed as a percentage to determine the value of the 1 C load characteristics of each all-solid-state secondary battery.

[0125] (Internal Short-Circuit Defect Rate) Twenty all-solid-state secondary batteries for each of the Examples and Comparative Examples were produced, and the proportion of batteries that had developed an internal short circuit was calculated as a percentage to determine the value of the internal short-circuit defect rate.

[0126] These results are shown in Table 1 together with the objects and conditions (temperature, time) of the heat treatment during the production of the all-solid-state secondary battery.

[0127]

[0128] In the all-solid-state secondary battery of Example 1 in which the heat treatment during production of the all-solid-state secondary battery was performed on the power generation element under conditions of 150°C x 180 minutes, the 1C load characteristic was high at 60% and the internal short circuit occurrence rate was also kept low at 5%.

[0129] Furthermore, in the all-solid-state secondary batteries of Examples 2 to 6, which were assembled using power generation elements that had been heat-treated under appropriate conditions, as in Example 1, the 1C load characteristics were as high as 50 to 60%, and the internal short circuit occurrence rate was also kept low at 5%.

[0130] In contrast, the all-solid-state secondary battery of Comparative Example 1, in which the power generation element was not heat-treated but the battery was assembled and then heat-treated under the same conditions as in Example 1, had a high 1C load characteristic of 60%, but a high internal short-circuit occurrence rate of 50%. This is thought to be due to partial melting of the polyethylene heat-shrink tubing covering the side of the cell assembly, resulting in a loss of insulation. The all-solid-state secondary battery of Comparative Example 2, in which the power generation element was not heat-treated but the battery was heat-treated at 110°C for 180 minutes after assembly, had a low internal short-circuit occurrence rate of 5%, similar to that of the battery of Example 1, but had a low 1C load characteristic of 30%, resulting in poor load characteristics. The all-solid-state secondary battery of Comparative Example 3, in which the heat treatment time was extended from 180 minutes for the battery of Comparative Example 2 to 1,440 minutes, improved the 1C load characteristic from 30% to 40% of that of the battery of Comparative Example 2, but was still low. It was found that unless the heat treatment was performed at a sufficiently high temperature, even if the heat treatment time was extended, it would not improve to the level of the load characteristic of the battery of Example 1.

[0131] The present invention can be implemented in other forms without departing from the spirit of the present invention. The embodiments disclosed in this application are merely examples, and the present invention is not limited to these embodiments. The scope of the present invention shall be interpreted in accordance with the appended claims rather than the description in the above specification, and all modifications within the scope of the claims are included in the scope of the claims.

[0132] The all-solid-state battery produced by the production method of the present invention can be used in the same applications as known primary batteries and secondary batteries, but as described above, due to its excellent heat resistance, it can be preferably used in applications where it is exposed to high temperatures.

[0133] REFERENCE SIGNS LIST 1, 2 All-solid-state battery 10 Outer can 20 Electrode body 20a, 20b, 20c, 20d, 20e, 20f, 20g, 20h Power generating element 21 Cell assembly 22 Holder 23 First holding part 24 Second holding part 30 Positive electrode lead 40 Negative electrode lead 50 Lid body 51 Lid body main body 52 Terminal 53 Insulator 54 Insulating sheet 60 Connection lead 201 Positive electrode layer 202 Negative electrode layer 203 Solid electrolyte layer 204 Positive electrode tab 205 Negative electrode tab 210a, 210b, 210c, 210d, 210e Insulating plate 212, 213 Heat-shrinkable tube 300, 301, 302 Current collector 400 Outer can 401 Sealed can 402 Gasket

Claims

1. A method for manufacturing an all-solid-state battery having at least one power generating element and an exterior body, wherein the power generating element has a positive electrode layer, a negative electrode layer, and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer, the method comprising: a power generating element heating step of heating the power generating element to 130°C or higher; a power generating element cooling step of cooling the power generating element that has undergone the power generating element heating step; and an exterior body accommodation step of accommodating the power generating element that has undergone the power generating element cooling step in the exterior body.

2. The method for producing an all-solid-state battery according to claim 1, wherein the solid electrolyte layer contains a sulfide-based solid electrolyte.

3. The method for manufacturing an all-solid-state battery according to claim 1, wherein the power generating element heating step heats the power generating element in an uncharged state.

4. The method for manufacturing an all-solid-state battery according to claim 1, wherein the exterior body has an insulating member inside.

5. The method for producing an all-solid-state battery according to claim 4, wherein the insulating member is made of resin.

6. The method for manufacturing an all-solid-state battery according to claim 1, wherein the exterior body has a cylindrical exterior can with a bottom and a lid.

7. The method for manufacturing an all-solid-state battery according to claim 1, wherein the exterior body is flat and has an exterior can and a sealing can.

8. The method for producing an all-solid-state battery according to claim 1, which has two or more of the power generating elements connected to each other via a current collector.

9. The method for manufacturing an all-solid-state battery according to claim 1, wherein a current collecting member is connected to the power generating element after the power generating element cooling step, and then the power generating element is subjected to the exterior housing step.

10. The method for manufacturing an all-solid-state battery according to claim 1, wherein after the power generating element cooling step, at least one of the power generating elements is covered with a resin insulating member and then subjected to the exterior housing step.

11. The method for manufacturing an all-solid-state battery according to claim 1, wherein after the power generating element cooling step, two or more power generating elements are assembled into a cell assembly, which is then subjected to the exterior housing step.

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