Solid-state battery and method for manufacturing solid-state battery

Abstract

To provide a solid-state battery capable of improving the bonding of an intermediate layer disposed between a negative electrode layer and a solid electrolyte layer to other layers.SOLUTION: A solid-state battery has a structure in which an anode layer, a solid electrolyte layer, and a cathode layer are laminated in this order, an intermediate layer is disposed between the anode layer and the solid electrolyte layer, and the porosity of the intermediate layer is 46% or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a solid-state battery and a method for manufacturing a solid-state battery. [Background technology]

[0002] In recent years, research and development into secondary batteries that contribute to energy efficiency has been conducted to ensure that more people have access to affordable, reliable, sustainable and advanced energy.

[0003] Known examples of such secondary batteries include solid-state batteries such as lithium metal batteries and lithium ion secondary batteries, in which a solid electrolyte layer is disposed between a positive electrode layer and a negative electrode layer. A technology for disposing another layer between the negative electrode layer and the solid electrolyte layer has been disclosed for solid-state batteries (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] US Patent Application Publication No. 2022 / 158226 Summary of the Invention [Problem to be solved by the invention]

[0005] The solid-state battery disclosed in Patent Document 1 has a conformal coating layer between the anode layer and the solid electrolyte layer. The conformal coating layer is said to contribute to reducing interfacial resistance and improving current uniformity. On the other hand, when another layer is disposed between the anode layer and the solid electrolyte layer, the interfacial adhesion between these layers also becomes important. For example, there was a problem in that desirable interfacial adhesion could not be obtained when joining high-density layers or low-density layers.

[0006] The present invention has been made in view of the above, and aims to provide a solid-state battery that can improve the bonding strength of an intermediate layer disposed between an anode layer and a solid electrolyte layer with other layers. [Means for solving the problem]

[0007] (1) A solid-state battery having a structure in which an anode layer, a solid electrolyte layer, and a cathode layer are stacked in this order, and an intermediate layer is disposed between the anode layer and the solid electrolyte layer; A solid-state battery, wherein the porosity of the intermediate layer is 46% or less.

[0008] According to the invention (1), it is possible to provide a solid-state battery capable of improving the bonding of the intermediate layer disposed between the negative electrode layer and the solid electrolyte layer to other layers.

[0009] (2) The solid-state battery according to (1), wherein the intermediate layer has a porosity of 44% or less.

[0010] According to the invention (2), the bonding strength of the intermediate layer disposed between the negative electrode layer and the solid electrolyte layer to other layers can be more preferably improved.

[0011] (3) The solid state battery according to (1) or (2), wherein an arithmetic mean height Sa of an interface between the intermediate layer and the solid electrolyte layer in contact with the intermediate layer is 0.2 or more.

[0012] According to the invention (3), the bonding strength of the intermediate layer disposed between the negative electrode layer and the solid electrolyte layer to other layers can be more preferably improved.

[0013] (4) The solid state battery according to any one of (1) to (3), wherein the particle size of the solid electrolyte constituting the solid electrolyte layer in contact with the intermediate layer is 0.2 to 5 μm, the content of the binder in the solid electrolyte layer is 5 to 25 mass %, the particle size of the particles constituting the intermediate layer is 5 to 300 nm, and the content of the binder in the intermediate layer is 1 to 10 mass %.

[0014] According to the invention (4), the bonding strength of the intermediate layer disposed between the negative electrode layer and the solid electrolyte layer to other layers can be more preferably improved.

[0015] (5) The solid state battery according to any one of (1) to (4), wherein the solid electrolyte layer is composed of a plurality of layers, and an arithmetic mean height Sa of an interface of the solid electrolyte layer arranged on the negative electrode layer side among the solid electrolyte layers is 1 or less.

[0016] According to the fifth aspect of the present invention, it is possible to improve the bonding between a layer such as an intermediate layer disposed on the negative electrode layer side and a solid electrolyte layer disposed on the negative electrode layer side.

[0017] (6) A method for manufacturing a solid-state battery having a structure in which an anode layer, a solid electrolyte layer, and a cathode layer are laminated in this order, wherein an intermediate layer is disposed between the anode layer and the solid electrolyte layer, the method comprising: a first pressing step of pre-pressing the intermediate layer; a second pressing step of transferring the intermediate layer that has been subjected to the first pressing step onto the anode layer and pressing the transferred intermediate layer to obtain an intermediate layer-anode layer laminate; and a third pressing step of disposing the solid electrolyte layer on a surface of the intermediate layer in the intermediate layer-anode layer laminate and pressing the transferred solid electrolyte layer to obtain a solid electrolyte layer-intermediate layer-anode layer laminate. and an integration pressing step of integrating the layers together, wherein the pressing pressure in the first pressing step is greater than the pressing pressure in the third pressing step.

[0018] According to the sixth aspect of the present invention, a solid-state battery can be manufactured that can improve the bonding strength of the intermediate layer disposed between the negative electrode layer and the solid electrolyte layer with other layers.

[0019] (7) The method for producing a solid-state battery according to (6), wherein the pressing pressure in the first pressing step is 600 MPa or more and 1200 MPa or less.

[0020] According to the seventh aspect of the present invention, a solid-state battery can be manufactured in which the bonding strength of the intermediate layer disposed between the negative electrode layer and the solid electrolyte layer to other layers is more preferably improved.

[0021] (8) The method for producing a solid-state battery according to claim 6, wherein the temperature during pressing in the first pressing step is equal to or higher than room temperature and equal to or lower than 100°C.

[0022] According to the invention (8), it is possible to increase the density of the intermediate layer. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a conceptual cross-sectional view showing the configuration of a solid-state battery according to an embodiment of the present invention. [Figure 2A] 1A to 1C are diagrams illustrating some steps in a method for manufacturing a solid-state battery according to an embodiment of the present invention. [Figure 2B] 1A to 1C are diagrams illustrating some steps in a method for manufacturing a solid-state battery according to an embodiment of the present invention. [Figure 2C] 1A to 1C are diagrams illustrating some steps in a method for manufacturing a solid-state battery according to an embodiment of the present invention. [Figure 2D] 1A to 1C are diagrams illustrating some steps in a method for manufacturing a solid-state battery according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] [Solid battery] As shown in FIG. 1 , the solid-state battery 1 has an electrode laminate in which an anode layer 2, a solid electrolyte layer 4, and a cathode layer 3 are laminated in this order. An intermediate layer 5 is disposed between the anode layer 2 and the solid electrolyte layer 4. In this embodiment, the laminate structure of the solid-state battery 1 will be described as the structure in which the anode layer 2, the intermediate layer 5, the solid electrolyte layer 4, the cathode layer 3, the solid electrolyte layer 4, the intermediate layer 5, and the anode layer 2 are laminated in this order as shown in FIG. 1 . However, the structure of the solid-state battery 1 is not limited to the above, and it is sufficient that the solid-state battery 1 has a structure in which the solid electrolyte layer 4 is laminated between the anode layer 2 and the cathode layer 3, and the intermediate layer 5 is disposed between the anode layer 2 and the solid electrolyte layer 4. In addition to the electrode laminate shown in FIG. 1 , the solid-state battery 1 may have a configuration that can be used in solid-state batteries, such as an exterior body.

[0025] The solid state battery 1 is not particularly limited, but may be a lithium ion solid state secondary battery or a lithium metal secondary battery.

[0026] (negative electrode layer) The anode layer 2 has an anode active material layer 21 and an anode current collector layer 22. The anode active material layer 21 is not particularly limited and can be made of a material that can be used as an anode active material for a solid-state battery. The anode active material layer 21 is preferably a lithium metal layer in which the anode active material is lithium metal. This is because, in the solid-state battery 1 according to the present invention, even if the anode active material layer 21 is made of a hard metal, it can adhere to the solid electrolyte layer 4 with high adhesion. The lithium metal includes not only elemental lithium metal but also lithium alloys, etc. The anode active material layer 21 can also be made of silicon-based active materials such as Si and Si alloys, lithium titanate (Li4Ti5O 12 The electrode may be composed of lithium transition metal oxides such as TiO2, Nb2O3 and WO3, metal sulfides, metal nitrides, carbon materials such as graphite, soft carbon and hard carbon, metallic indium, etc.

[0027] The negative electrode active material layer 21 may contain other materials that can be contained in a negative electrode active material layer of a solid-state battery. Examples of such materials include a solid electrolyte, a conductive additive, and a binder. Examples of the solid electrolyte include the same solid electrolyte contained in the solid electrolyte layer 4 described below. Examples of the conductive additive include carbon black, natural graphite, carbon fiber, and carbon nanotubes. Examples of the binder include a nitrile polymer, a polyester polymer, an acrylic acid polymer, a cellulose polymer, a styrene polymer, a styrene-butadiene polymer, a vinyl acetate polymer, a urethane polymer, and a fluoroethylene polymer.

[0028] The negative electrode current collector layer 22 is not particularly limited, but may be made of copper, nickel, stainless steel, or the like. Examples of the shape of the negative electrode current collector layer 22 include foil, plate, mesh, nonwoven fabric, and foam. A portion of the negative electrode current collector layer 22 extends in a predetermined direction to form a negative electrode current collector tab 22a.

[0029] (middle class) The intermediate layer 5 is disposed between the anode layer 2 and the solid electrolyte layer 4. For example, when the solid battery 1 is a lithium metal battery, the intermediate layer 5 has the function of uniformly depositing lithium metal. Therefore, the interface between the intermediate layer 5 and the first solid electrolyte layer 41 is stabilized. When the solid battery 1 is a lithium metal secondary battery having the intermediate layer 5, the solid battery 1 may be an anode-free battery in which the anode active material layer 21 is not present during the initial charge. In this case, a lithium metal layer is formed as the anode active material layer 21 after the initial charge / discharge. In this embodiment, the intermediate layer 5 will be described as being a single layer, but the number of layers of the intermediate layer 5 is not particularly limited.

[0030] The material constituting the intermediate layer 5 is not particularly limited, and examples thereof include metals capable of forming an alloy with lithium and amorphous carbon. Examples of metals capable of forming an alloy with lithium include tin (Sn), silicon (Si), zinc (Zn), magnesium (Mg), gold (Au), platinum (Pt), palladium (Pd), silver (Ag), aluminum (Al), bismuth (Bi), and antimony (Sb). The metal capable of forming an alloy with lithium may be in the form of nanoparticles. Examples of amorphous carbon include carbon blacks such as acetylene black, furnace black, and ketjen black, as well as coke and activated carbon. The amorphous carbon may be graphitizable carbon (soft carbon), non-graphitizable carbon (hard carbon), CNT (carbon nanotube), fullerene, or graphene. The intermediate layer 5 may contain a binder in addition to the above materials. The binder may be the same material as the binder that can be contained in the negative electrode active material layer 21.

[0031] The intermediate layer 5 is densified in advance by a first pressing step described below. This improves the bonding strength between the intermediate layer 5 and the solid electrolyte layer 4 (first solid electrolyte layer 41). The porosity of the intermediate layer 5 is 46% or less. The porosity of the intermediate layer 5 is preferably 44% or less, and may be 42% or less. The porosity of the intermediate layer 5 may be 40% or more.

[0032] The particle size of the particles constituting the intermediate layer 5 is preferably 5 to 300 nm. The content of the binder relative to the total mass of the intermediate layer 5 may be 1 to 15 mass %, and is preferably 1 to 10 mass %.

[0033] (solid electrolyte layer) The solid electrolyte layer 4 is formed between the intermediate layer 5 and the positive electrode layer 3. In this embodiment, the solid electrolyte layer 4 has a structure in which a first solid electrolyte layer 41 disposed on the intermediate layer side, a second solid electrolyte layer 42, and a third solid electrolyte layer 43 disposed on the positive electrode side are stacked in this order. The configuration of the solid electrolyte layer 4 is not limited to the above, and may be, for example, a solid electrolyte layer consisting of one or two layers.

[0034] The first solid electrolyte layer 41 is disposed in contact with the intermediate layer 5 as shown in FIG. 1. The solid electrolyte material constituting the first solid electrolyte layer 41 is not particularly limited, and may be any material that can be used as an electrolyte in a solid-state battery. Examples include inorganic solid electrolytes such as sulfide solid electrolyte materials, oxide solid electrolyte materials, halide solid electrolytes, and lithium-containing salts, as well as polymer solid electrolytes such as polyethylene oxide. The above solid electrolytes may be used alone or in combination of two or more.

[0035] The solid electrolyte material constituting the first solid electrolyte layer 41 is preferably in a particulate form. The particle size (D50, median diameter) of the solid electrolyte material constituting the first solid electrolyte layer 41 is preferably 0.2 to 5 μm. The particle size of the solid electrolyte material is preferably 1 μm or less. This allows the first solid electrolyte layer 41 to be easily densified. The particle size of the solid electrolyte material is more preferably 0.7 μm or less.

[0036] The density of the first solid electrolyte layer 41 is 1.65 g / cm 3 It is preferable that the value is 1.80 / cm or more. 3 The density of the first solid electrolyte layer 41 is not particularly limited, but is preferably 2.00 / cm 3 or more. 3 It may be the following:

[0037] The first solid electrolyte layer 41 may contain, in addition to the solid electrolyte material, a material that can be used in a solid electrolyte layer of a solid-state battery. For example, the first solid electrolyte layer 41 may contain a binder. As the binder, the same material as the binder that can be contained in the negative electrode active material layer 21 can be used. When the first solid electrolyte layer 41 contains a binder, the content of the binder is preferably 5 to 25 mass % with respect to the total mass of the first solid electrolyte layer 41.

[0038] The interfacial roughness of the interface between the intermediate layer 5 and the first solid electrolyte layer 41 is optimized by the particle size and binder content of the particles constituting the intermediate layer 5, and the particle size and binder content of the solid electrolyte material constituting the first solid electrolyte layer 41. This improves the bonding between the intermediate layer 5 and the first solid electrolyte layer 41. The interfacial roughness of the interface between the intermediate layer 5 and the first solid electrolyte layer 41 is expressed, for example, by the arithmetic mean height Sa. The arithmetic mean height Sa is preferably 0.2 or more. The arithmetic mean height Sa is more preferably 1 or less.

[0039] The thickness of the first solid electrolyte layer 41 (the length of each layer in the stacking direction) is preferably 7 μm or less. This allows the first solid electrolyte layer 41 to be easily densified. The thickness of the first solid electrolyte layer 41 is more preferably 3 μm or less. The thickness of the first solid electrolyte layer 41 is not particularly limited, but may be 1 μm or more.

[0040] The porosity of the first solid electrolyte layer 41 is preferably 7% or less. This can be said to increase the density of the first solid electrolyte layer 41. Furthermore, the efficiency of charge transfer within the first solid electrolyte layer 41 is improved. The porosity of the first solid electrolyte layer 41 is more preferably 4% or less. The porosity of the first solid electrolyte layer 41 is not particularly limited, but may be 1% or more.

[0041] The second solid electrolyte layer 42 and the third solid electrolyte layer 43 may have the same configuration as the first solid electrolyte layer 41. In this embodiment, the third solid electrolyte layer 43 is disposed in contact with the positive electrode layer 3. The second solid electrolyte layer 42 is disposed between the first solid electrolyte layer 41 and the third solid electrolyte layer 43. It is possible to arbitrarily determine whether the second solid electrolyte layer 42 and the third solid electrolyte layer 43 are provided separately from the first solid electrolyte layer 41. Alternatively, it may be effective to provide a densified solid electrolyte layer or a high-strength solid electrolyte layer including a support in addition to the first solid electrolyte layer 41, which is a layer for improving interfacial bonding. Examples of the support include three-dimensional structures such as mesh, woven fabric, nonwoven fabric, embossed body, punched body, expanded body, and foam.

[0042] (positive electrode layer) The positive electrode layer 3 has a positive electrode active material layer 31 and a positive electrode current collector layer 32. In this embodiment, the positive electrode layer 3 has a configuration in which two positive electrode active material layers 31 are stacked on both sides of one positive electrode current collector layer 32. However, the configuration of the positive electrode layer 3 is not limited to the above, and the positive electrode layer 3 may have a configuration in which one positive electrode active material layer 31 is stacked on one side of one positive electrode current collector layer 32.

[0043] The positive electrode active material layer 31 is not particularly limited and can be made of a material that can be used as a positive electrode active material for a solid-state battery. Examples of the positive electrode active material that makes up the positive electrode active material layer 31 include LiCoO2, LiNiO2, LiCo x Ni y Mn z O2 (x+y+z=1), LiVO2, LiCrO2, etc., layered positive electrode active material particles, LiMn2O4, Li(Ni 0.25 Mn 0.75 Examples of such positive electrode active materials include spinel-type positive electrode active materials such as LiCoPO, LiMnPO, and LiFePO; solid solution oxides (LiMnO-LiMO (M=Co, Ni, etc.)); conductive polymers such as polyaniline and polypyrrole; sulfides such as LiS, CuS, Li-Cu-S compounds, TiS, FeS, MoS, and Li-Mo-S compounds; and mixtures of sulfur and carbon. The positive electrode active material may be one of the above materials, or may be composed of two or more of the above materials.

[0044] An insulating frame 6 may be provided around the outer periphery of the positive electrode active material layer 31. The insulating frame 6 can prevent short circuits in the solid state battery 1 and improve its strength. In this embodiment, the insulating frame 6 is disposed so as to cover the side surfaces of the two positive electrode active material layers 31 formed on both sides of the positive electrode current collector layer 32. The insulating frame 6 also abuts against a portion of the stacking surface of the positive electrode current collector layer 32, and has a gap through which a positive electrode current collector tab 32a (described later) extends. The material for the insulating frame 6 is not particularly limited, but examples thereof include insulating oxides such as alumina, resins such as polyvinylidene fluoride (PVDF), and rubbers such as styrene-butadiene rubber (SBR).

[0045] The positive electrode current collector layer 32 is not particularly limited, and can be made of, for example, aluminum, stainless steel, conductive carbon (graphite, carbon nanotubes, etc.), etc. Examples of the shape of the positive electrode current collector layer 32 include foil, plate, mesh, nonwoven fabric, and foam. A portion of the positive electrode current collector layer 32 extends in a predetermined direction to form a positive electrode current collector tab 32a.

[0046] [Solid-state battery manufacturing method] A method for manufacturing a solid-state battery according to this embodiment will be described below with reference to FIGS. 2A to 2D. The method for manufacturing a solid-state battery according to this embodiment is a method for manufacturing a solid-state battery having an electrode laminate La in which an anode layer 2, an intermediate layer 5, a solid electrolyte layer 4, and a cathode layer 3 are stacked in this order. The method for manufacturing a solid-state battery according to this embodiment includes at least a first pressing step for pre-pressing the intermediate layer 5, a second pressing step for transferring the intermediate layer 5 that has been subjected to the first pressing step to the anode layer 2 and pressing it to obtain an intermediate layer-anode layer laminate L1, a third pressing step for placing a solid electrolyte layer 4 on the surface of the intermediate layer 5 in the intermediate layer-anode layer laminate L1 and pressing it to obtain a solid electrolyte layer-intermediate layer-anode layer laminate, and an integration pressing step for integrating the layers. The first pressing step, second pressing step, and third pressing step are performed in this order.

[0047] The first pressing step is a step of pre-pressing the intermediate layer 5 to densify it. The intermediate layer 5 is formed, for example, by dispersing the materials constituting the intermediate layer 5 in a solvent, applying a slurry obtained by this to a support sheet, and then drying the slurry. By pressing the intermediate layer 5 in this state, the intermediate layer 5 is densified, and finally an intermediate layer 5 having a porosity of 46% or less can be formed. The pressing pressure in the first pressing step is higher than the pressing pressure in the third pressing step described below. The pressing pressure in the first pressing step is, for example, preferably 600 MPa or more and 1200 MPa or less, and more preferably 800 MPa or more.

[0048] The temperature during pressing in the first pressing step is preferably equal to or higher than room temperature and equal to or lower than 100° C. Room temperature means, for example, 25° C. By setting the pressing temperature as described above, the intermediate layer can be preferably densified.

[0049] As shown in FIG. 2A , the second pressing step is a step of press-bonding the negative electrode layer 2 and the intermediate layer 5 that has been subjected to the first pressing step to obtain an intermediate layer-negative electrode layer laminate L1. A specific method for disposing the intermediate layer 5 on the surface of the negative electrode layer 2 that faces the negative electrode active material layer 21, i.e., the lamination surface, is a method of transferring the intermediate layer 5 using the support sheet (intermediate layer transfer sheet). The pressure used to press the negative electrode layer 2 and the intermediate layer 5 in the second pressing step is not particularly limited as long as the pressure does not excessively deform the negative electrode layer 2 and the intermediate layer 5 and allows them to be bonded together without peeling in a subsequent step. The pressing pressure in the second pressing step is, for example, in the range of 300 MPa or more and 800 MPa or less.

[0050] As shown in FIG. 2B , the third pressing step is a step of placing a material constituting the solid electrolyte layer 4 (in this embodiment, the first solid electrolyte layer 41) on the lamination surface of the intermediate layer 5 in the intermediate layer-anode layer laminate L1 and press-bonding them to obtain a solid electrolyte layer-intermediate layer-anode layer laminate L2. The first solid electrolyte layer 41 may be placed on the lamination surface of the intermediate layer 5 using a solid electrolyte layer transfer sheet, or a solid electrolyte sheet formed in advance into a sheet shape. The solid electrolyte layer transfer sheet has the same configuration as the intermediate layer transfer sheet.

[0051] The pressing pressure in the third pressing step is, for example, preferably 500 MPa or more and 800 MPa or less, and more preferably 600 MPa or more.

[0052] As shown in FIG. 2C , the solid electrolyte layer 4 may be formed as a plurality of layers, with a third solid electrolyte layer 43 provided on the cathode layer 3 side. In this case, a fourth press step may be provided in which a material constituting the third solid electrolyte layer 43 is placed on the laminated surface of the cathode layer 3 and press-bonded to obtain a solid electrolyte layer-cathode layer laminate L3. In this embodiment, the cathode layer 3 has cathode active material layers 31 formed on both sides of the cathode current collector layer 32, and the third solid electrolyte layer 43 is disposed on both cathode active material layers 31. There are no particular limitations on the fourth press step, other than that it be performed before the integration press step.

[0053] 2D, the integration press step is a step of press-bonding a solid electrolyte layer-intermediate layer-anode layer laminate L2 and a layer including a cathode layer 3 to obtain an electrode laminate La. The layer including the cathode layer 3 may be the cathode layer 3 alone, or may be a solid electrolyte layer-cathode layer laminate L3 obtained in the fourth press step. Furthermore, during the integration press step, a second solid electrolyte layer 42 may be disposed between the solid electrolyte layer-intermediate layer-anode layer laminate L2 and the cathode layer 3 or the solid electrolyte layer-cathode layer laminate L3 so as to face each solid electrolyte layer, and then press-bonded.

[0054] Since the integration press step is a step of integrating the layers, it is preferable to apply a pressure that does not excessively deform the layers. The pressure in the integration press step is, for example, in the range of 500 MPa or more and 900 MPa or less.

[0055] In each of the above steps, the press bonding apparatus is not particularly limited, and a roll press, a plate press, or an isostatic press (CIP, WIP) apparatus can be used. When press bonding is performed using a roll press, the objects to be press-bonded may be conveyed to the roll press in the same direction or in different directions. The temperature during pressing in each of the above steps may be room temperature, for example, 10 to 35°C.

[0056] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and can be modified as appropriate within the scope of the present invention. [Explanation of symbols]

[0057] 1 solid state battery 2. Negative electrode layer 3 Positive electrode layer 4 Solid electrolyte layer 5. Middle class

Claims

1. A solid-state battery having a structure in which an anode layer, a solid electrolyte layer, and a cathode layer are stacked in this order, an intermediate layer is disposed between the negative electrode layer and the solid electrolyte layer; A solid-state battery, wherein the porosity of the intermediate layer is 46% or less.

2. The solid-state battery according to claim 1 , wherein the porosity of the intermediate layer is 44% or less.

3. 3. The solid state battery according to claim 1, wherein an arithmetic mean height Sa of an interface between the intermediate layer and the solid electrolyte layer in contact with the intermediate layer is 0.2 or more.

4. the particle size of the solid electrolyte constituting the solid electrolyte layer in contact with the intermediate layer is 0.2 to 5 μm, and the content of the binder in the solid electrolyte layer is 5 to 25 mass %, 3. The solid state battery according to claim 1, wherein the particle diameter of the particles constituting the intermediate layer is 5 to 300 nm, and the content of the binder in the intermediate layer is 1 to 10 mass %.

5. the solid electrolyte layer is composed of a plurality of layers, 3. The solid state battery according to claim 1, wherein the solid electrolyte layer arranged on the negative electrode layer side has an arithmetic mean height Sa of 1 or less at an interface on the negative electrode layer side.

6. A method for manufacturing a solid-state battery having a structure in which an anode layer, a solid electrolyte layer, and a cathode layer are stacked in this order, comprising: an intermediate layer is disposed between the negative electrode layer and the solid electrolyte layer; a first pressing step of pre-pressing the intermediate layer; a second pressing step of transferring the intermediate layer that has been subjected to the first pressing step onto a negative electrode layer and pressing the transferred intermediate layer onto the negative electrode layer to obtain an intermediate layer-negative electrode layer laminate; a third pressing step of placing the solid electrolyte layer on a lamination surface of the intermediate layer in the intermediate layer-negative electrode layer laminate and pressing the solid electrolyte layer to obtain a solid electrolyte layer-intermediate layer-negative electrode layer laminate; and an integration pressing step for integrating the layers, a pressing pressure in the first pressing step being greater than a pressing pressure in the third pressing step.

7. The method for manufacturing a solid-state battery according to claim 6 , wherein the pressing pressure in the first pressing step is 600 MPa or more.

8. The method for manufacturing a solid-state battery according to claim 6 , wherein the temperature during pressing in the first pressing step is equal to or higher than room temperature and equal to or lower than 100° C.

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