All-solid-state battery and method for manufacturing same

Abstract

The present invention addresses the problem of providing an all-solid-state battery in which a solid electrolyte layer has high ion conductivity, and a method for manufacturing the same. In order to solve the problem, an all-solid-state battery has a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer, and the solid electrolyte layer is a laminate having a first solid electrolyte layer and a second solid electrolyte layer laminated on one surface of the solid electrolyte layer containing the base material. The first solid electrolyte layer contains a porous base material and a first solid electrolyte composition containing a solid electrolyte and filling pores of the porous base material, and the second solid electrolyte layer contains a second solid electrolyte composition containing a solid electrolyte and does not contain a base material.

Description

Technical Field

[0001] The present invention relates to an all-solid-state battery and a manufacturing method thereof. Background Art

[0002] In recent years, research and development of secondary batteries, which contribute to improved energy efficiency, has been underway to ensure greater access to affordable, reliable, sustainable, and advanced energy. Among these secondary batteries, all-solid-state batteries, comprising a press-bonded laminate composed of a solid electrolyte layer disposed between positive and negative electrode layers, have garnered particular attention due to their non-flammable nature, resulting in improved safety and higher energy density. As a known solid electrolyte layer for all-solid-state batteries, a method of forming a porous substrate by filling the pores with a solid electrolyte is known (Patent Documents 1 and 2).

[0003] [Prior Art Literature]

[0004] (Patent Document)

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2015-153460

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 2021-163759 Summary of the Invention

[0007] [Problems to be solved by the invention]

[0008] However, improving high-rate performance is a major challenge in all-solid-state batteries. Improving the ionic conductivity of the solid electrolyte layer is an effective way to improve high-rate performance in all-solid-state batteries. However, a solid electrolyte layer filled with a solid electrolyte in the pores of a porous substrate can sometimes generate pinholes between the pores of the porous substrate and the solid electrolyte, reducing ionic conductivity.

[0009] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an all-solid-state battery having a solid electrolyte layer with high ion conductivity and a method for manufacturing the same.

[0010] [Technical means to solve the problem]

[0011] The present inventors have discovered that forming a solid electrolyte layer by pressing a second solid electrolyte layer containing a second solid electrolyte composition and no substrate onto one surface of a first solid electrolyte layer filled with a first solid electrolyte composition in the pores of a porous substrate can solve the aforementioned problems, leading to the completion of the present invention. Accordingly, the present invention provides the following.

[0012] (1) An all-solid-state battery comprising: a press-bonded laminated body formed by press-bonding a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer; and the solid electrolyte layer comprising a first solid electrolyte layer and a second solid electrolyte layer press-bonded to one surface of the first solid electrolyte layer, wherein the first solid electrolyte layer is a substrate-containing body comprising a porous substrate and a first solid electrolyte composition containing a solid electrolyte filled in pores of the porous substrate, and the second solid electrolyte layer is a substrate-free body comprising a second solid electrolyte composition containing a solid electrolyte and does not contain a substrate.

[0013] According to the all-solid-state battery of (1), since the first solid electrolyte layer and the second solid electrolyte layer of the press-bonded laminate are press-bonded, pinholes formed in the first solid electrolyte layer are filled with the second solid electrolyte composition of the second solid electrolyte layer. Therefore, the solid electrolyte layer of the all-solid-state battery having the press-bonded laminate has high ion conductivity and improved high-rate characteristics.

[0014] (2) The all-solid-state battery according to (1), wherein the first solid electrolyte layer is press-bonded to the positive electrode layer, and the second solid electrolyte layer is press-bonded to the negative electrode layer.

[0015] According to the all-solid-state battery of (2), since the first solid electrolyte layer including the porous substrate is pressed against the positive electrode layer, a high-strength material can be used for the positive electrode layer. In addition, since the second solid electrolyte layer not including the porous substrate is pressed against the negative electrode layer, a low-strength material can be used for the negative electrode layer.

[0016] (3) The all-solid-state battery according to (1) or (2), wherein the outer peripheral end of the first solid electrolyte layer is larger than the outer peripheral end of at least one of the positive electrode layer and the negative electrode layer in a plan view.

[0017] According to the all-solid-state battery of (3), the outer peripheral end of the first solid electrolyte layer is larger than the outer peripheral end of at least one of the positive electrode layer and the negative electrode layer in a plan view, so that the positive electrode layer and the negative electrode layer are less likely to short-circuit.

[0018] (4) An all-solid-state battery according to any one of (1) to (3), wherein the first solid electrolyte composition and the second solid electrolyte composition each contain a binder, and the binder content of the first solid electrolyte composition is higher than the binder content of the second solid electrolyte composition.

[0019] According to the all-solid-state battery of (4), since the first solid electrolyte composition has a high binder content, the adhesion to the porous substrate is improved, and pinholes are less likely to form in the first solid electrolyte layer. Since the second solid electrolyte composition has a low binder content, the ion conductivity of the second solid electrolyte layer is improved.

[0020] (5) An all-solid-state battery according to any one of (1) to (4), wherein the positive electrode layer has a sheet-shaped positive electrode collector and two positive electrode active material layers stacked on both surfaces of the positive electrode collector, and the negative electrode layer is configured in a manner that sandwiches the positive electrode layer.

[0021] According to the all-solid-state battery of (5), a solid electrolyte layer is arranged on the surface of the two positive electrode active material layers to form a closed bag structure in which the positive electrode layer is surrounded by the solid electrolyte layer. Therefore, it is possible to prevent the negative electrode tab connected to the negative electrode layer from being wrapped around the positive electrode layer and causing a short circuit between the positive electrode layer and the negative electrode layer.

[0022] (6) A method for manufacturing an all-solid-state battery, comprising the following steps: pressurizing a stacked body to pressurize the layers; and the stacked body is stacked with a positive electrode layer, a negative electrode layer, and a solid electrolyte layer arranged between the positive electrode layer and the negative electrode layer, the solid electrolyte layer having a first solid electrolyte layer and a second solid electrolyte layer arranged on one surface of the first solid electrolyte layer, the first solid electrolyte layer being a substrate-containing body comprising a porous substrate and a first solid electrolyte composition containing a solid electrolyte filled in the pores of the porous substrate, and the second solid electrolyte layer being a substrate-free body comprising a second solid electrolyte composition containing a solid electrolyte and not containing a substrate.

[0023] According to the method for manufacturing an all-solid-state battery of (6), since the first solid electrolyte layer and the second solid electrolyte layer are pressed together, the pinholes formed in the first solid electrolyte layer can be filled with the second solid electrolyte composition of the second solid electrolyte layer. As a result, the solid electrolyte layer of the obtained all-solid-state battery has high ion conductivity and improved high-rate characteristics.

[0024] (7) The method for manufacturing an all-solid-state battery according to (6), wherein the first solid electrolyte layer of the stack is stacked on the positive electrode layer, and the second solid electrolyte layer is stacked on the negative electrode layer.

[0025] According to the method for manufacturing an all-solid-state battery of (7), since the first solid electrolyte layer including the porous substrate is pressed against the positive electrode layer, a high-strength material can be used for the positive electrode layer. In addition, since the second solid electrolyte layer not including the porous substrate is pressed against the negative electrode layer, a low-strength material can be used for the negative electrode layer.

[0026] (8) The method for manufacturing an all-solid-state battery according to (7), wherein the positive electrode layer and the first solid electrolyte layer of the stack are pressure-bonded.

[0027] According to the manufacturing method of the all-solid-state battery of (8), since the positive electrode layer and the first solid electrolyte layer are pre-pressed together, the adhesion between the positive electrode layer and the first solid electrolyte layer of the obtained all-solid-state battery becomes higher, and the ion conductivity between the positive electrode layer and the solid electrolyte layer is improved.

[0028] (9) The method for manufacturing a solid-state battery according to (7) or (8), wherein the negative electrode layer and the second solid electrolyte layer of the stack are pressure-bonded.

[0029] According to the manufacturing method of the all-solid-state battery of (9), since the negative electrode layer and the second solid electrolyte layer are pre-pressed together, the adhesion between the negative electrode layer and the second solid electrolyte layer of the obtained all-solid-state battery becomes higher, and the ion conductivity between the negative electrode layer and the solid electrolyte layer is improved.

[0030] (Effects of the Invention)

[0031] According to the present invention, an all-solid-state battery having a solid electrolyte layer with high ion conductivity and a method for manufacturing the same can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a plan view showing a compressed laminated body of an all-solid-state battery according to one embodiment of the present invention.

[0033] Figure 2 yes Figure 2 Cross-sectional view along line II-II.

[0034] Figure 3 It is a cross-sectional view illustrating a method for manufacturing an all-solid-state battery according to one embodiment of the present invention, and is a cross-sectional view showing a positive electrode layer-first solid electrolyte layer press-bonded stack.

[0035] Figure 4 1 is a cross-sectional view showing a negative electrode layer-second solid electrolyte layer press-bonded stack obtained by a method for manufacturing an all-solid-state battery according to one embodiment of the present invention.

[0036] Figure 5 This is a cross-sectional view illustrating a step of press-bonding a stacked body, which is one step of a method for manufacturing an all-solid-state battery according to one embodiment of the present invention. DETAILED DESCRIPTION

[0037] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiments described below are examples of the present invention, and the present invention is not limited to the following embodiments.

[0038] Figure 1 This is a plan view showing a compressed laminated body of an all-solid-state battery according to one embodiment of the present invention. Figure 2 yes Figure 1 Cross-sectional view along line II-II.

[0039] like Figures 1 to 2 As shown, the press-bonded laminate 10 is a laminate formed by press-bonding a positive electrode layer 20 , a negative electrode layer 30 , and a solid electrolyte layer disposed between the positive electrode layer 20 and the negative electrode layer 30 .

[0040] The positive electrode layer 20 includes a positive electrode current collector 21 and two positive electrode active material layers 22 laminated on both surfaces of the positive electrode current collector 21. The positive electrode current collector 21 is connected to the positive electrode tab 25. The negative electrode layers 30 are arranged opposite to each other, sandwiching the positive electrode layer 20. The two opposing negative electrode layers 30 each include a negative electrode current collector 31 and a metal layer 32 laminated on the surface of the negative electrode current collector 31 facing the solid electrolyte layer 40. The negative electrode current collector 31 is connected to the negative electrode tab 35. The solid electrolyte layer 40 is arranged between the positive electrode active material layer 22 and the negative electrode current collector 31. The solid electrolyte layer 40 includes a first solid electrolyte layer 41 and a second solid electrolyte layer 42 press-bonded to one surface of the first solid electrolyte layer 41. The first solid electrolyte layer 41 is press-bonded to the positive electrode layer 20, and the second solid electrolyte layer 42 is press-bonded to the negative electrode layer 30. The outer peripheral edge of the first solid electrolyte layer 41 is larger than the outer peripheral edge of the positive electrode layer 20 when viewed from above.

[0041] The first solid electrolyte layer 41 is a substrate-containing body comprising a porous substrate and a first solid electrolyte composition filling the pores of the porous substrate. The second solid electrolyte layer 42 is a substrate-free body comprising a second solid electrolyte composition containing a solid electrolyte and does not contain a substrate. By pressing the first solid electrolyte layer 41 and the second solid electrolyte layer 42 together, the second solid electrolyte layer 42 is pressed against the pinholes formed in the first solid electrolyte layer 41, thereby filling the pinholes with the second solid electrolyte composition.

[0042] The positive electrode current collector 21 is not particularly limited in material or shape as long as it has the function of collecting current from the positive electrode layer 20. Examples of materials for the positive electrode current collector 21 include aluminum, aluminum alloys, stainless steel, nickel, iron, and titanium, with aluminum, aluminum alloys, and stainless steel being preferred. Examples of the shape of the positive electrode current collector 21 include foil and plate.

[0043] The positive electrode active material layer 22 contains at least one positive electrode active material. There is no particular limitation on the positive electrode active material, and materials used in the positive electrode layer of a conventional all-solid-state battery can be used. As the positive electrode active material, for example, a layered active material containing lithium, a spinel-type active material, an olivine-type active material, etc. can be used. Specific examples of positive electrode active materials include lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), LiNiO2, and the like. p Mn q Co r O2(p+q+r=1), LiNi p Al q Co r O2(p+q+r=1), lithium manganate (LiMn2O4), Li 1+x Mn 2-x-y Heterogeneous element substitution Li-Mn spinel represented by MO4 (x+y=2, M=at least one selected from Al, Mg, Co, Fe, Ni and Zn), lithium titanate (an oxide containing Li and Ti), lithium metal phosphate (LiMPO4, M=at least one selected from Fe, Mn, Co and Ni), etc.

[0044] From the perspective of improving lithium ion conductivity, the positive electrode active material layer 22 may optionally contain a solid electrolyte. Furthermore, to improve conductivity, a conductive additive may optionally be included. Furthermore, from the perspective of achieving flexibility, a binder may optionally be included. The solid electrolyte, conductive additive, and binder are not particularly limited, and materials commonly used in the positive electrode layer of all-solid-state batteries may be used.

[0045] The material of the positive electrode tab 25 may be the same as or different from the material of the positive electrode current collector 21. The positive electrode tab 25 may also be integrally connected to the positive electrode current collector 21. In this embodiment, the positive electrode tab 25 is formed by extending the positive electrode current collector 21 and is integrally connected to the positive electrode current collector 21.

[0046] The negative electrode current collector 31 is not particularly limited in material or shape as long as it has the function of collecting current from the negative electrode layer 30. Examples of materials for the negative electrode current collector 31 include nickel, copper, and stainless steel. Examples of the shape of the negative electrode current collector 31 include foil and plate.

[0047] As long as the metal layer 32 has the function of densely depositing lithium ions, there are no particular restrictions on the material or shape. As the metal layer 32, a metallic lithium layer or a layer of a metal that forms an alloy with lithium can be used. Examples of metals that form alloys with lithium include Mg, Si, Au, Ag, In, Ge, Sn, Pb, Al, and Zn. The metal forming the metal layer 32 can be in powder form or in thin film form. By using the negative electrode layer 30 having this metal layer 32, a uniform lithium deposition layer can be formed on the surface of the metal layer 32.

[0048] The material of the negative electrode tab 35 may be the same as or different from the material of the negative electrode current collector 31. The negative electrode tab 35 may also be integrally connected to the negative electrode current collector 31. In this embodiment, the negative electrode tab 35 is formed by extending the negative electrode current collector 31 and is integrally connected to the negative electrode current collector 31.

[0049] The thickness of the first solid electrolyte layer 41 of the solid electrolyte layer 40 may be the same as or different from the thickness of the second solid electrolyte layer 42. For example, the thickness of the second solid electrolyte layer 42 may be thicker than the thickness of the first solid electrolyte layer 41.

[0050] As the porous base material included in the first solid electrolyte layer 41 , for example, nonwoven fabric or woven fabric can be used.

[0051] The first solid electrolyte composition of first solid electrolyte layer 41 and the second solid electrolyte composition of second solid electrolyte layer 42 may also contain a solid electrolyte and a binder. The solid electrolytes of the first and second solid electrolyte compositions may be the same or different. The first solid electrolyte composition may also contain two or more solid electrolytes having different average particle sizes. For example, it may contain a fine solid electrolyte with an average particle size ranging from 0.1 μm to less than 0.5 μm and a coarse solid electrolyte with an average particle size ranging from 1.0 μm to 10.0 μm. The ratio of the fine solid electrolyte to the coarse solid electrolyte may also be within a range of 1:9 to 9:1 by mass. The fine solid electrolyte improves the bonding between the first solid electrolyte layer 41 and the positive electrode layer 20. The coarse solid electrolyte improves the packing of the solid electrolyte composition in the first solid electrolyte layer 41. The average particle size of the solid electrolyte of the second solid electrolyte composition may also be, for example, within a range from 1.0 μm to 10.0 μm. The average particle size of the solid electrolyte of the first solid electrolyte composition may also be smaller than the average particle size of the solid electrolyte of the second solid electrolyte composition. In addition, the average particle size is a value measured by a laser diffraction scattering method.

[0052] The solid electrolytes of the first solid electrolyte composition and the second solid electrolyte composition are not particularly limited as long as they have lithium ion conductivity, and for example, sulfide solid electrolytes, oxide solid electrolytes, nitride solid electrolytes, halide solid electrolytes, etc. can be used.

[0053] Examples of sulfide solid electrolytes include Li2S-P2S5, Li2S-P2S5-LiI, etc. The sulfide solid electrolyte may have an argyrodite-type crystal structure.

[0054] Examples of oxide solid electrolytes include NASICON type oxides, garnet type oxides, and perovskite type oxides. Examples of NASICON type oxides include oxides containing Li, Al, Ti, P, and O (e.g., Li 1.5 Al 0.5 Ti 1.5 (PO4)3). Examples of garnet-type oxides include oxides containing Li, La, Zr, and O (e.g., Li7La3Zr2O 12 Examples of perovskite-type oxides include oxides containing Li, La, Ti, and O (eg, LiLaTiO 3 ).

[0055] The binder of the first solid electrolyte composition and the second solid electrolyte composition may be the same or different. There is no particular limitation on the type of binder, and the binder used in the solid electrolyte layer of a conventional all-solid-state battery may be used. The binder content of the first solid electrolyte composition can be set, for example, from the perspective of the adhesion between the first solid electrolyte composition and the porous substrate, the overall strength of the first solid electrolyte layer 41, and the ionic conductivity. The binder content of the second solid electrolyte composition can be set, for example, from the perspective of the adhesion with the first solid electrolyte layer 41 and the overall ionic conductivity of the second solid electrolyte layer 42. The binder content of the first solid electrolyte composition may also be higher than the binder content of the second solid electrolyte composition. The binder content of the first solid electrolyte composition may also be, for example, in the range of 1.5 times or more and 10 times or less of the binder content of the second solid electrolyte composition.

[0056] The compressed laminate 10 is housed in an exterior body (not shown). The exterior body includes a positive electrode terminal connected to the positive electrode tab 25 and a negative electrode terminal connected to the negative electrode tab 35 .

[0057] A laminated film can be used as the material for the outer body. A laminated film having a three-layer structure, in which an inner resin layer, a metal layer, and an outer resin layer are laminated in this order from the inner side, can be used. The outer resin layer can be, for example, a polyamide (nylon) layer or a polyethylene terephthalate (PET) layer, the metal layer can be, for example, an aluminum layer, and the inner resin layer can be, for example, a polyethylene layer or a polypropylene layer.

[0058] In the press-bonded laminate 10 of the present embodiment constructed as described above, since the first solid electrolyte layer 41 and the second solid electrolyte layer 42 of the solid electrolyte layer 40 are press-bonded, pinholes formed in the first solid electrolyte layer 41 are filled with the second solid electrolyte composition of the second solid electrolyte layer 42. Therefore, the solid electrolyte layer 40 of the all-solid-state battery including the press-bonded laminate 10 has high ion conductivity and improved high-rate characteristics.

[0059] In the compressed laminate 10 of this embodiment, since the first solid electrolyte layer 41 is compressed to the positive electrode layer 20, a high-strength material can be used for the positive electrode active material layer 22. Furthermore, since the second solid electrolyte layer 42 is compressed to the negative electrode layer 30, a low-strength material can be used for the metal layer 32.

[0060] In the compressed laminate 10 of this embodiment, since the outer peripheral end of the first solid electrolyte layer 41 is larger than the outer peripheral end of the positive electrode layer 20 when viewed from above, a short circuit between the positive electrode layer 20 and the negative electrode layer 30 is less likely to occur. In addition, by arranging the solid electrolyte layer 40 on the surfaces of the two positive electrode active material layers 22, the positive electrode layer 20 forms a closed bag structure surrounded by the solid electrolyte layer 40. This can prevent the negative electrode tab 35 from being wrapped around the positive electrode layer 20 and causing a short circuit between the positive electrode layer 20 and the negative electrode layer 30.

[0061] In the press-bonded laminate 10 of this embodiment, since the first solid electrolyte composition has a high binder content, adhesion to the porous substrate is improved, and pinholes are less likely to form in the first solid electrolyte layer 41. Since the second solid electrolyte composition has a low binder content, the ion conductivity of the second solid electrolyte layer 42 is improved.

[0062] Reference Figures 3 to 5 A method for producing the compression-bonded laminate 10 according to this embodiment will be described.

[0063] Figure 3 It is a cross-sectional view illustrating a method for manufacturing an all-solid-state battery according to one embodiment of the present invention, and is a cross-sectional view showing a positive electrode layer-first solid electrolyte layer press-bonded stack. Figure 4 1 is a cross-sectional view showing a negative electrode layer-second solid electrolyte layer press-bonded stack obtained by a method for manufacturing an all-solid-state battery according to one embodiment of the present invention. Figure 5This is a cross-sectional view illustrating a step of press-bonding a stacked body, which is one step of a method for manufacturing an all-solid-state battery according to one embodiment of the present invention.

[0064] In the method for manufacturing the pressure-bonded laminate 10 of this embodiment, first, as shown in FIG. Figure 3 As shown, a positive electrode layer-first solid electrolyte layer pressed laminate 11 is obtained by pressing the positive electrode layer 20 and the first solid electrolyte layer 41. The positive electrode layer-first solid electrolyte layer pressed laminate 11 can be produced by superimposing the positive electrode active material layer 22 of the positive electrode layer 20 and the first solid electrolyte layer 41 and applying pressure. A roller press can be used as a pressurizing device.

[0065] In addition, if Figure 4 As shown, a negative electrode layer-second solid electrolyte layer laminate 12 is obtained by compressing the metal layer 32 of the negative electrode layer 30 and the second solid electrolyte layer 42. The negative electrode layer-second solid electrolyte layer laminate 12 can be manufactured by overlapping the metal layer 32 of the negative electrode layer 30 and the second solid electrolyte layer 42 and applying pressure. A roller press can be used as a pressurizing device. The pressing pressure can also be lower than the pressure used when manufacturing the positive electrode layer-first solid electrolyte layer laminate 11.

[0066] Then, if Figure 5 As shown, the first solid electrolyte layer 41 of the positive electrode layer-first solid electrolyte layer pressed laminate 11 is overlapped with the second solid electrolyte layer 42 of the negative electrode layer-second solid electrolyte layer pressed laminate 12 to obtain a laminate having the positive electrode layer 20, the negative electrode layer 30, and the first solid electrolyte layer 41 and the second solid electrolyte layer 42 disposed between the positive electrode layer 20 and the negative electrode layer 30. This laminate is then pressurized to press-bond the first solid electrolyte layer 41 and the second solid electrolyte layer 42. The pressing pressure may be lower than the pressure used to produce the positive electrode layer-first solid electrolyte layer pressed laminate 11. Alternatively, the pressing pressure may be higher than the pressure used to produce the metal layer 32 and the second solid electrolyte layer 42.

[0067] The all-solid-state battery can be manufactured, for example, as follows: The positive electrode tab 25 of the obtained press-bonded laminate 10 is connected to the positive electrode terminal, and the negative electrode tab 35 is connected to the negative electrode terminal. Next, the press-bonded laminate 10 is housed in an outer casing so that the ends of the positive and negative terminals protrude, and the outer casing is sealed.

[0068] According to the method for manufacturing the press-bonded laminate 10 of the present embodiment described above, since the first solid electrolyte layer 41 and the second solid electrolyte layer 42 are press-bonded, pinholes formed in the first solid electrolyte layer 41 can be filled with the second solid electrolyte composition of the second solid electrolyte layer 42. Therefore, in an all-solid-state battery using the obtained press-bonded laminate 10, the ion conductivity of the solid electrolyte layer 40 is high, and high-rate characteristics are improved.

[0069] In the method for manufacturing the press-bonded laminate 10 of this embodiment, since the first solid electrolyte layer 41 is press-bonded to the positive electrode layer 20, a high-strength material can be used for the positive electrode active material layer 22. Furthermore, since the second solid electrolyte layer 42 is press-bonded to the negative electrode layer 30, a low-strength material can be used for the metal layer 32.

[0070] In the method for manufacturing the press-bonded laminate 10 of this embodiment, since the positive electrode layer 20 and the first solid electrolyte layer 41 are pre-press-bonded together using the positive electrode layer-first solid electrolyte layer press-bonded laminate 11, the resulting press-bonded laminate 10 has improved adhesion between the positive electrode layer 20 and the first solid electrolyte layer 41, and improved ion conductivity between the positive electrode layer 20 and the solid electrolyte layer 40. Furthermore, since the negative electrode layer 30 and the second solid electrolyte layer 42 are pre-press-bonded together using the negative electrode layer-second solid electrolyte layer press-bonded laminate 12, the resulting press-bonded laminate 10 has improved adhesion between the negative electrode layer 30 and the second solid electrolyte layer 42, and improved ion conductivity between the negative electrode layer 30 and the solid electrolyte layer 40.

[0071] As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment.

[0072] For example, in the present embodiment, the positive electrode layer 20 includes the positive electrode active material layer 22 stacked on both surfaces of the positive electrode current collector 21 . However, the positive electrode active material layer 22 may be stacked on only one surface of the positive electrode current collector 21 .

[0073] In this embodiment, the first solid electrolyte layer 41 is pressed against the positive electrode layer 20 and the second solid electrolyte layer 42 is pressed against the negative electrode layer 30 . However, the second solid electrolyte layer 42 may be pressed against the positive electrode layer 20 and the first solid electrolyte layer 41 may be pressed against the negative electrode layer 30 .

[0074] In addition, in this embodiment, the negative electrode layer 30 has a metal layer 32, but the metal layer 32 can also be omitted, so that lithium is precipitated on the surface of the negative electrode collector 31. In addition, instead of the metal layer 32, a layer containing a negative electrode active material that can insert and release lithium ions can also be used. Examples of negative electrode active materials include lithium transition metal oxides such as lithium titanate, transition metal oxides such as TiO2, Nb2O3 and WOn, Si, SiO, metal sulfides, metal nitrides, and carbon materials such as artificial graphite, natural graphite, graphite, soft carbon and hard carbon. From the perspective of improving lithium ion conductivity, the negative electrode active material layer can also optionally contain a solid electrolyte. In addition, in order to improve conductivity, a conductive auxiliary agent can also be optionally contained. Furthermore, from the perspective of exhibiting flexibility, etc., a binder can also be optionally contained. For the solid electrolyte, conductive auxiliary agent and binder, substances commonly used in solid secondary batteries can be used.

[0075] In addition, in the method for manufacturing the press-bonded laminate 10 of this embodiment, the first solid electrolyte layer 41 of the positive electrode layer-first solid electrolyte layer press-bonded laminate 11 is press-bonded to the second solid electrolyte layer 42 of the negative electrode layer-second solid electrolyte layer press-bonded laminate 12, but the present invention is not limited to this. For example, a laminate in which the positive electrode layer 20, the first solid electrolyte layer 41, the second solid electrolyte layer 42, and the negative electrode layer 30 are laminated separately may be press-bonded to form the layers. Furthermore, for the solid electrolyte layer 40 formed by press-bonding the first solid electrolyte layer 41 and the second solid electrolyte layer 42, the laminate disposed between the positive electrode layer 20 and the negative electrode layer 30 may be press-bonded to form the layers.

[0076] Reference numerals

[0077] 10: Press-bonding the laminate

[0078] 11: Positive electrode layer-first solid electrolyte layer pressed laminate

[0079] 12: Negative electrode layer-second solid electrolyte layer laminate

[0080] 20: Positive electrode layer

[0081] 21: Positive electrode collector

[0082] 22: Positive electrode active material layer

[0083] 25: Positive electrode tab

[0084] 30: Negative electrode layer

[0085] 31: Negative electrode collector

[0086] 32: Metal layer

[0087] 35: Negative electrode tab

[0088] 40: Solid electrolyte layer

[0089] 41: First solid electrolyte layer

[0090] 42: Second solid electrolyte layer

Claims

1. An all-solid-state battery comprising: A laminated body is formed by pressing a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer; and The solid electrolyte layer includes a first solid electrolyte layer and a second solid electrolyte layer press-bonded to one surface of the first solid electrolyte layer. The first solid electrolyte layer is a substrate-containing body comprising a porous substrate and a first solid electrolyte composition containing a solid electrolyte filling pores of the porous substrate. The second solid electrolyte layer includes a second solid electrolyte composition containing a solid electrolyte and is a substrate-free body that does not include a substrate.

2. The all-solid-state battery according to claim 1, wherein The first solid electrolyte layer is press-bonded to the positive electrode layer, and the second solid electrolyte layer is press-bonded to the negative electrode layer.

3. The all-solid-state battery according to claim 1 or 2, wherein: The outer peripheral end portion of the first solid electrolyte layer is larger than the outer peripheral end portion of at least one of the positive electrode layer and the negative electrode layer in a plan view.

4. The all-solid-state battery according to claim 1 or 2, wherein The first solid electrolyte composition and the second solid electrolyte composition each contain a binder, and the binder content of the first solid electrolyte composition is higher than the binder content of the second solid electrolyte composition.

5. The all-solid-state battery according to claim 1 or 2, wherein: The positive electrode layer includes a sheet-shaped positive electrode current collector and two positive electrode active material layers stacked on both surfaces of the positive electrode current collector, and the negative electrode layer is disposed so as to sandwich the positive electrode layer.

6. A method for manufacturing an all-solid-state battery, comprising the following steps: Pressurizing the laminate to bond the layers together; and The stacked body is stacked with a positive electrode layer, a negative electrode layer and a solid electrolyte layer arranged between the positive electrode layer and the negative electrode layer, the solid electrolyte layer has a first solid electrolyte layer and a second solid electrolyte layer arranged on one surface of the first solid electrolyte layer, the first solid electrolyte layer is a substrate-containing body comprising a porous substrate and a first solid electrolyte composition containing a solid electrolyte filled in the pores of the porous substrate, the second solid electrolyte layer comprises a second solid electrolyte composition containing a solid electrolyte, and is a substrate-free body that does not contain a substrate.

7. The method for manufacturing an all-solid-state battery according to claim 6, wherein: In the stacked body, the first solid electrolyte layer is stacked on the positive electrode layer, and the second solid electrolyte layer is stacked on the negative electrode layer.

8. The method for manufacturing an all-solid-state battery according to claim 7, wherein: The positive electrode layer and the first solid electrolyte layer of the stacked body are pressure-bonded.

9. The method for manufacturing an all-solid-state battery according to claim 7 or 8, wherein: The negative electrode layer and the second solid electrolyte layer of the stacked body are pressure-bonded.

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