All-solid battery and manufacturing method of all-solid battery

Abstract

To provide an all-solid battery capable of suppressing expansion caused by charging and discharging.SOLUTION: The all-solid battery includes a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode current collector that are layered in this order on at least one surface of a positive electrode current collector in which the negative electrode active material layer contains a negative electrode active material, the negative electrode active material is Si or a Si alloy. The filling rate of the solid electrolyte layer is 95% or more. The filling rate of the negative electrode active material layer is between 40% and 68% of the filling rate of the solid electrolyte layer.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Lithium-ion secondary batteries containing non-aqueous electrolytes have high voltage and high capacity, and are widely used as power sources for electronic devices such as mobile phones and laptops, and electric vehicles. However, because non-aqueous electrolytes are flammable, there are safety concerns about lithium-ion secondary batteries containing non-aqueous electrolytes. Therefore, in order to improve safety, development of all-solid-state batteries containing non-flammable solid electrolytes is also underway.

[0003] Patent Document 1 discloses an all-solid-state lithium ion secondary battery including a negative electrode current collector layer, a negative electrode active material layer, a solid electrolyte layer, a positive electrode active material layer, and a positive electrode current collector layer in this order, characterized in that the negative electrode active material layer contains an alloy material containing at least one selected from silicon and tin, the solid electrolyte layer has a filling factor calculated by a predetermined formula of 85% or less, the negative electrode current collector layer has an elongation of 7.0% or more in a tensile test, and the positive electrode current collector layer has an elongation of 4.0% or more in a tensile test.

[0004] Patent Document 2 discloses a lithium ion secondary battery including a positive electrode, a negative electrode, a polymer layer, and a lithium ion permeable insulating layer, the polymer layer being formed on the surface of the negative electrode active material layer and containing a first polymer and first inorganic oxide particles, and the lithium ion permeable insulating layer being disposed so as to be interposed between the positive electrode and the negative electrode.

[0005] Patent Document 3 discloses an all-solid-state battery in which an anode foil, an anode layer, a solid electrolyte layer, and a cathode layer are laminated in this order, the areas of the solid electrolyte layer and the anode layer are larger than the area of ​​the cathode layer, the filling rate of the anode layer is 80% or more, the filling rate of the solid electrolyte layer is 70% or more, and the filling rate of the cathode layer is 75% or more, and the solid electrolyte layer protrudes from the entire outer periphery of the positive electrode layer in a plan view.

[0006] Patent Document 4 discloses a negative electrode comprising a layer of a negative electrode mixture containing graphite particles and ion-conductive solid electrolyte particles, the graphite particles having a diameter of 3.5 mm. 2 / g or more, and the content of graphite particles in the negative electrode mixture layer is 70% by mass or more and 90% by mass or less. The document also describes that the packing rate of the negative electrode active material layer may be 95% or more. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2018-45779 A [Patent Document 2] JP 2010-250968 A [Patent Document 3] JP 2019-160516 A [Patent Document 4] JP 2019-16484 A Summary of the Invention [Problem to be solved by the invention]

[0008] The expansion of a battery caused by the volume change of the negative electrode active material layer due to charging and discharging has been a problem for some time. This is because there is a risk of cracking or peeling of the electrodes inside the expanded battery, which leads to concerns about a decrease in cycle characteristics. In Patent Document 1, the expansion of a battery is suppressed by adjusting the packing rate of the solid electrolyte layer. In Patent Document 2, the expansion of a battery is suppressed by providing a specific polymer layer. In Patent Document 3, the expansion of a battery is suppressed by adjusting the packing rates of the negative electrode layer, the positive electrode layer, and the solid electrolyte layer.

[0009] In recent years, developments have been made to increase the capacity of negative electrodes. As the capacity of negative electrodes increases, the volume change of the negative electrode active material layer due to charging and discharging becomes larger, and the expansion of the battery also becomes significant. Therefore, a technology to further suppress the expansion of the battery is desired.

[0010] In view of the above, a main object of the present disclosure is to provide an all-solid-state battery capable of suppressing expansion due to charging and discharging, and a manufacturing method thereof. [Means for solving the problem]

[0011] As one aspect for solving the above problems, the present disclosure provides an all-solid-state battery in which a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode current collector are laminated in this order on at least one surface of a positive electrode current collector, the negative electrode active material layer contains a negative electrode active material, and the filling rate of the negative electrode active material layer is less than 80%.

[0012] In the all-solid-state battery, the positive electrode active material layer contains a positive electrode active material, the solid electrolyte layer contains a solid electrolyte, the positive electrode active material layer has a filling rate of 85% or more, and the solid electrolyte layer has a filling rate of 85% or more.

[0013] The all-solid-state battery may be in the following form. That is, the all-solid-state battery may be a battery in which a first positive electrode active material layer, a first solid electrolyte layer, a first negative electrode active material layer, and a first negative electrode current collector are laminated in this order on one surface of a positive electrode current collector, a second positive electrode active material layer, a second solid electrolyte layer, a second negative electrode active material layer, and a second negative electrode current collector are laminated in this order on the other surface of the positive electrode current collector, the first negative electrode active material layer and the second negative electrode active material layer contain a negative electrode active material, and the filling rate of the first negative electrode active material layer and the second negative electrode active material layer is less than 80%. In this form, the first positive electrode active material layer and the second positive electrode active material layer may contain a positive electrode active material, the first solid electrolyte layer and the first solid electrolyte layer may contain a solid electrolyte, the filling rate of the first positive electrode active material layer and the second positive electrode active material layer may be 85% or more, and the filling rate of the first solid electrolyte layer and the second solid electrolyte layer may be 85% or more.

[0014] In the all-solid-state battery, the negative electrode active material may be Si or a Si alloy.

[0015] As one aspect for solving the above problems, the present disclosure provides a method for manufacturing an all-solid-state battery, comprising: a negative electrode manufacturing step of obtaining a negative electrode by laminating a negative electrode active material layer and a negative electrode current collector; a positive electrode-solid electrolyte layer laminate manufacturing step of obtaining a positive electrode-solid electrolyte layer laminate by laminating a positive electrode active material layer and a solid electrolyte layer in this order on at least one surface of a positive electrode current collector; and a lamination step of laminating the positive electrode-solid electrolyte layer laminate and the negative electrode such that a negative electrode active material layer is disposed on the surface of the solid electrolyte layer. The negative electrode active material layer contains a negative electrode active material, and the filling rate of the negative electrode active material layer is less than 80%.

[0016] In the method for manufacturing the all-solid-state battery, the positive electrode active material layer contains a positive electrode active material, the solid electrolyte layer contains a solid electrolyte, the filling rate of the positive electrode active material layer is 85% or more, and the filling rate of the solid electrolyte layer may be 85% or more.

[0017] The method for manufacturing the all-solid-state battery may also be the following aspect. That is, a first negative electrode manufacturing step of obtaining a first negative electrode by laminating a first negative electrode active material layer and a first negative electrode current collector; a second negative electrode manufacturing step of obtaining a second negative electrode by laminating a second negative electrode active material layer and a second negative electrode current collector; a positive electrode-solid electrolyte layer laminate manufacturing step of obtaining a positive electrode-solid electrolyte layer laminate by laminating a first positive electrode active material layer and a first solid electrolyte layer in this order on one surface of a positive electrode current collector, and laminating a second positive electrode active material layer and a second solid electrolyte layer in this order on the other surface of the positive electrode current collector; and a lamination step of laminating the positive electrode-solid electrolyte layer laminate, the first negative electrode, and the second negative electrode such that the first negative electrode active material layer is disposed on the surface of the first solid electrolyte layer and the second negative electrode active material layer is disposed on the surface of the second solid electrolyte layer. The first negative electrode active material layer and the second negative electrode active material layer contain a negative electrode active material, and the filling rate of the first negative electrode active material layer and the second negative electrode active material layer is less than 80%. In this aspect, the first positive electrode active material layer and the second positive electrode active material layer contain a positive electrode active material, the first solid electrolyte layer and the second solid electrolyte layer contain a solid electrolyte, the filling rate of the first positive electrode active material layer and the second positive electrode active material layer is 85% or more, and the filling rate of the first solid electrolyte layer and the second solid electrolyte layer may be 85% or more.

[0018] In the method for manufacturing the all-solid-state battery described above, the negative electrode active material may be Si or an Si alloy.

Advantages of the Invention

[0019] According to the present disclosure, expansion due to charge and discharge can be suppressed.

Brief Description of the Drawings

[0020] [Figure 1] It is a schematic cross-sectional view of the all-solid-state battery 100. [Diagram 2] It is a schematic cross-sectional view of the all-solid-state battery 200. [Diagram 3] It is a flowchart of the method 1000 for manufacturing an all-solid-state battery. [Figure 4] It is a flowchart of the method 2000 for manufacturing an all-solid-state battery.

Embodiments for Carrying Out the Invention

[0021] 1. All-solid-state battery The all-solid-state battery of the present disclosure will be described with reference to the all-solid-state batteries 100 and 200, which are one embodiment.

[0022] 1.1. All-solid-state battery 100 In the all-solid-state battery 100, a positive electrode active material layer 20, a solid electrolyte layer 30, a negative electrode active material layer 40, and a negative electrode current collector 50 are laminated in this order on at least one surface of the positive electrode current collector 10. The negative electrode active material layer contains a negative electrode active material, and the filling rate of the negative electrode active material layer is less than 80%. A schematic cross-sectional view of the all-solid-state battery 100 is shown in FIG. 1. FIG. 1 shows a form in which the positive electrode active material layer 20, the solid electrolyte layer 30, the negative electrode active material layer 40, and the negative electrode current collector 50 are laminated in this order on one surface of the positive electrode current collector 10.

[0023] The all-solid-state battery 100 may include a positive electrode current collector 10, a positive electrode active material layer 20, a solid electrolyte layer 30, a negative electrode active material layer 40, and a negative electrode current collector 50 in this order. For example, a laminate including the positive electrode current collector 10, the positive electrode active material layer 20, the solid electrolyte layer 30, the negative electrode active material layer 40, and the negative electrode current collector 50 in this order may be used as one structural unit, and a plurality of such laminates may be included. In addition, when a plurality of laminates are included, the adjacent laminates may share a collector. For example, the adjacent laminates may share a positive electrode current collector. Specifically, the all-solid-state battery may include a first positive electrode active material layer, a first solid electrolyte layer, a first negative electrode active material layer, and a first negative electrode current collector stacked on one surface of the positive electrode current collector, and a second positive electrode active material layer, a second solid electrolyte layer, a second negative electrode active material layer, and a second negative electrode current collector stacked on the other surface of the positive electrode current collector. This embodiment will be described later in the section on the all-solid-state battery 200.

[0024] 1.1.1. Positive electrode current collector 10 The material of the positive electrode current collector 10 is not particularly limited, and can be appropriately selected from known materials according to the purpose. For example, Cu, Ni, Cr, Au, Pt, Ag, Al, Fe, Ti, Zn, Co, stainless steel, etc. are included. The thickness of the positive electrode current collector is not particularly limited, and may be appropriately set according to the desired battery performance. For example, it is in the range of 0.1 μm to 1 mm.

[0025] 1.1.2. Positive electrode active material layer 20 The positive electrode active material layer 20 contains a positive electrode active material. The positive electrode active material can be appropriately selected from known positive electrode active materials used in all-solid-state lithium-ion secondary batteries. Examples include lithium cobalt oxide, lithium nickel cobalt aluminum oxide (NCA), lithium nickel cobalt manganese oxide (NCM), and lithium manganese oxide. The particle size of the positive electrode active material is not particularly limited, but is in the range of 1 μm to 100 μm, for example. The content of the positive electrode active material in the positive electrode active material layer 20 is not particularly limited, but is in the range of 50% by weight to 99% by weight, for example. The surface of the positive electrode active material may be covered with an oxide layer such as a lithium niobate layer, a lithium titanate layer, or a lithium phosphate layer.

[0026] The positive electrode active material layer 20 may optionally include a solid electrolyte. The solid electrolyte can be appropriately selected from known solid electrolytes used in all-solid-state lithium ion secondary batteries. Examples of the solid electrolyte include sulfide solid electrolytes, oxide solid electrolytes, nitride solid electrolytes, and halide solid electrolytes. A sulfide solid electrolyte is preferable. The content of the solid electrolyte in the positive electrode active material layer is not particularly limited, but is, for example, in the range of 1% by weight to 50% by weight.

[0027] The sulfide solid electrolyte preferably contains Li, M (M is preferably at least one of P, Ge, Si, Sn, B, and Al), and S. The sulfide solid electrolyte may further contain a halogen element. Examples of the halogen element include F, Cl, Br, and I. The amorphous sulfide solid electrolyte may further contain O.

[0028] As the sulfide solid electrolyte, for example, Li 2 SP 2 S 5 , Li 2 SP 2 S 5 - LiI, Li 2 SP 2 S 5 -GeS 2 , Li 2 SP 2 S 5 -Li 2 O, Li 2 SP 2 S 5 -Li 2 O-LiI, Li 2 SP 2 S 5 -LiI-LiBr, Li 2 S-SiS 2 , Li 2 S-SiS 2 - LiI, Li 2 S-SiS 2 -LiBr, Li 2 S-SiS 2 -LiCl, Li 2 S-SiS2 -B 2 S 3 - LiI, Li 2 S-SiS 2 -P 2 S 5 - LiI, Li 2 S.B. 2 S 3 , Li 2 SP 2 S 5 -Z m S n (where m and n are positive numbers. Z is Ge, Zn, or Ga.) Li 2 S-GeS 2 , Li 2 S-SiS 2 -Li 3 PO 4 , Li 2 S-SiS 2 -Li x MO y (where x and y are positive numbers, and M is P, Si, Ge, B, Al, Ga, or In.)

[0029] Examples of oxide solid electrolytes include lithium lanthanum zirconium-containing composite oxides (LLZO), Al-doped LLZO, lithium lanthanum titanium-containing composite oxides (LLTO), Al-doped LLTO, and lithium oxynitride phosphate (LIPON). Examples of nitride solid electrolytes include Li 3 N, Li 3 Examples of the halide solid electrolyte include LiF, LiCl, LiBr, LiI, and LiI-Al. 2 O 3 Examples include:

[0030] The positive electrode active material layer 20 may optionally include a conductive assistant. The conductive assistant can be appropriately selected from known conductive assistants used in all-solid-state lithium-ion secondary batteries. Examples of the conductive assistant include carbon materials such as acetylene black, ketjen black, and vapor-grown carbon fiber (VGCF), and metal materials such as nickel, aluminum, and stainless steel. The content of the conductive assistant in the positive electrode active material layer 20 is not particularly limited, but is, for example, in the range of 0.1% by weight to 10% by weight.

[0031] The positive electrode active material layer 20 may optionally include a binder. The binder can be appropriately selected from known binders used in all-solid-state lithium ion secondary batteries. Examples of the binder include butadiene rubber (BR), butylene rubber (IIR), acrylate butadiene rubber (ABR), styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVdF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVdF-HFP), etc. The content of the binder in the positive electrode active material layer 20 is not particularly limited, but is, for example, in the range of 0.1% by weight to 10% by weight.

[0032] The shape of the positive electrode active material layer 20 is not particularly limited, but is preferably a sheet shape. The thickness of the positive electrode active material layer 20 is not particularly limited and may be appropriately set according to the desired battery performance. For example, it is in the range of 0.1 μm to 1 mm.

[0033] The filling rate of the positive electrode active material layer 20 is not particularly limited, but from the viewpoint of reducing the battery resistance, it may be 85% or more, 90% or more, or 95% or more.

[0034] Here, in this specification, the "filling rate" can be calculated from the following formula: In the formula, "electrode layer" means the electrode layer for which the filling rate is to be calculated, i.e., any one of the positive electrode active material layer, the solid electrolyte layer, or the negative electrode active material layer. Filling rate (%) = [{Weight of electrode layer (g) ÷ True specific gravity of electrode layer (g / cm 3 )}÷{apparent volume of electrode layer (cm 3 )}]×100

[0035] 1.1.3.Solid electrolyte layer 30 The solid electrolyte layer 30 contains at least a solid electrolyte. The solid electrolyte can be appropriately selected from among known solid electrolytes used in all-solid-state lithium ion secondary batteries. For example, the solid electrolyte that can be contained in the above-mentioned positive electrode active material layer 20 can be used. The content of the solid electrolyte in the solid electrolyte layer 30 is not particularly limited, but is, for example, in the range of 50% by weight to 99% by weight.

[0036] The solid electrolyte layer 30 may optionally include a binder. The binder can be appropriately selected from known binders used in all-solid-state lithium ion secondary batteries. For example, the binder can be the binder that can be contained in the positive electrode active material layer 20 described above. The content of the binder in the solid electrolyte layer 30 is not particularly limited, but is, for example, in the range of 0.1% by weight to 10% by weight.

[0037] The shape of the solid electrolyte layer 30 is not particularly limited, but is preferably a sheet shape. The thickness of the solid electrolyte layer 30 is not particularly limited and may be appropriately set according to the desired battery performance. For example, it is in the range of 0.1 μm to 1 mm.

[0038] The filling rate of the solid electrolyte layer 30 is not particularly limited, but from the viewpoint of reducing the battery resistance, it may be 85% or more, 90% or more, or 95% or more.

[0039] 1.1.4.Negative electrode active material layer 40 The negative electrode active material layer 40 includes a negative electrode active material. The negative electrode active material can be appropriately selected from known negative electrode active materials used in all-solid-state lithium ion secondary batteries. Examples of the negative electrode active material include silicon and Si alloys, tin and tin alloys, silicon oxide and other silicon-based active materials, graphite, hard carbon and other carbon-based active materials, lithium titanate and other oxide-based active materials, metallic lithium and lithium alloys.

[0040] Among them, the negative electrode active material is preferably Si or a Si alloy, or tin and a tin alloy. In particular, Si or a Si alloy is preferably used. This is because these negative electrode active materials have a large theoretical discharge capacity. Also, it is known that the volume change due to charging and discharging is particularly large, and by setting the filling rate of the negative electrode active material layer 20 to less than 80%, the volume change of the negative electrode active material can be absorbed and the expansion of the battery can be suppressed.

[0041] The negative electrode active material layer 40 may optionally include a solid electrolyte. The solid electrolyte can be appropriately selected from among known solid electrolytes used in all-solid-state lithium ion secondary batteries. For example, the solid electrolyte that can be contained in the positive electrode active material layer 20 described above can be used. The content of the solid electrolyte in the negative electrode active material layer 40 is not particularly limited, but is, for example, in the range of 1% by weight to 50% by weight.

[0042] The negative electrode active material layer 40 may optionally include a conductive assistant. The conductive assistant can be appropriately selected from known conductive assistants used in all-solid-state lithium ion secondary batteries. For example, the conductive assistant that can be contained in the positive electrode active material layer 20 described above can be used. The content of the conductive assistant in the negative electrode active material layer 40 is not particularly limited, but is, for example, in the range of 0.1% by weight to 10% by weight.

[0043] The negative electrode active material layer 40 may optionally include a binder. The binder can be appropriately selected from known binders used in all-solid-state lithium ion secondary batteries. For example, the binder can be the binder that can be contained in the positive electrode active material layer 20 described above. The content of the binder in the negative electrode active material layer 40 is not particularly limited, but is, for example, in the range of 0.1% by weight to 10% by weight.

[0044] The shape of the negative electrode active material layer 40 is not particularly limited, but is preferably a sheet shape. The thickness of the negative electrode active material layer 40 is not particularly limited and may be appropriately set according to the desired battery performance. For example, it is in the range of 0.1 μm to 1 mm.

[0045] The filling rate of the negative electrode active material layer 40 is less than 80%. This allows the negative electrode active material layer 40 itself to absorb the volume change of the negative electrode active material due to charging and discharging, thereby suppressing the expansion of the all-solid-state battery. This is particularly effective when Si or a Si alloy, which undergoes a large volume change due to charging and discharging, is used as the negative electrode active material. On the other hand, if the filling rate of the negative electrode active material layer 40 is 80% or more, the negative electrode active material layer 40 itself cannot absorb the volume change of the negative electrode active material due to charging and discharging, and there is a risk that the negative electrode active material layer 40 will crack or peel off, which may result in a decrease in cycle characteristics.

[0046] The filling rate of the negative electrode active material layer 40 is not particularly limited as long as it is less than 80%, but may be, for example, 70% or less, or 60% or less. The smaller the filling rate, the greater the ability of the negative electrode active material layer 40 itself to absorb the volume change of the negative electrode active material. However, if the filling rate is too small, there is a concern that the mechanical strength and energy density of the negative electrode active material layer 40 may decrease. Therefore, the filling rate of the negative electrode active material layer 40 may be 30% or more, or 40% or more.

[0047] 1.1.5. Negative electrode current collector 50 The material of the negative electrode current collector 50 can be appropriately selected from known materials depending on the purpose. For example, Cu, Ni, Cr, Au, Pt, Ag, Al, Fe, Ti, Zn, Co, stainless steel, etc. are included. The thickness of the negative electrode current collector 50 is not particularly limited and may be appropriately set depending on the desired battery performance. For example, it is in the range of 0.1 μm to 1 mm.

[0048] 1.1.6. Manufacturing method of the all-solid-state battery 100 There is no particular limitation on the method for manufacturing the all-solid-state battery 100. For example, the positive electrode current collector 10, the positive electrode active material layer 20, the solid electrolyte layer 30, the negative electrode active material layer 40, and the negative electrode current collector 50 may be prepared separately and stacked to produce the all-solid-state battery 100. After stacking, the stack may be appropriately pressed.

[0049] The electrode layers (positive electrode active material layer 20, solid electrolyte layer 30, and negative electrode active material layer 40) can be produced, for example, as follows. The materials constituting the electrode layers are mixed and pressed to produce the electrode layers. Alternatively, the materials constituting the electrode layers are dispersed in an organic solvent to obtain a slurry, and the obtained slurry is then applied to a current collector or a substrate and dried to produce the electrode layers.

[0050] On the other hand, the all-solid-state battery 100 is characterized in that the filling rate of the negative electrode active material layer 40 is less than 80%, but from the viewpoint of reducing the battery resistance, it is considered that the filling rates of the positive electrode active material layer 20 and the solid electrolyte layer 30 are made larger than the filling rate of the negative electrode active material layer 40. From the viewpoint of efficiently manufacturing such an all-solid-state battery 100, a manufacturing method 1000 described below may be adopted.

[0051] 1.2.All-solid-state battery 200 In the all-solid-state battery 200, a first positive electrode active material layer 121, a first solid electrolyte layer 131, a first negative electrode active material layer 141, and a first negative electrode current collector 151 are laminated in this order on one surface of a positive electrode current collector 110, and a second positive electrode active material layer 122, a second solid electrolyte layer 132, a second negative electrode active material layer 142, and a second negative electrode current collector 152 are laminated in this order on the other surface of the positive electrode current collector 110, the first negative electrode active material layer 141 and the second negative electrode active material layer 142 contain a negative electrode active material, and the filling rate of the first negative electrode active material layer 141 and the second negative electrode active material layer 142 is less than 80%. The all-solid-state battery 200 is a subordinate concept of the all-solid-state battery 100, and shows an example of the form of a monopolar battery. FIG. 2 shows a schematic cross-sectional view of the all-solid-state battery 200.

[0052] 1.2.1. Positive electrode current collector 110 Possible configurations of the positive electrode current collector 110 are similar to those of the positive electrode current collector 10, and therefore will not be described here.

[0053] 1.2.2. First positive electrode active material layer 121, second positive electrode active material layer 122 The first positive electrode active material layer 121 is laminated on one surface of the positive electrode collector 110, and the second positive electrode active material layer 122 is laminated on the other surface of the positive electrode collector 110. The configurations that can be adopted by the first positive electrode active material layer 121 and the second positive electrode active material layer 122 are similar to the configurations that can be adopted by the positive electrode active material layer 20, so a description thereof will be omitted here. However, the configurations of the first positive electrode active material layer 121 and the second positive electrode active material layer 122 may be the same or different. The filling rate of the first positive electrode active material layer 121 and the second positive electrode active material layer 122 is not particularly limited, but may be 85% or more, 90% or more, or 95% or more from the viewpoint of reducing the battery resistance.

[0054] 1.2.3. First solid electrolyte layer 131, second solid electrolyte layer 132 The first solid electrolyte layer 131 is laminated on one surface of the first positive electrode active material layer 121, and the second solid electrolyte layer 132 is laminated on the other surface of the second positive electrode active material layer 122. The configurations that can be adopted by the first solid electrolyte layer 131 and the second solid electrolyte layer 132 are similar to the configurations that can be adopted by the solid electrolyte layer 30, so a description thereof will be omitted here. However, the configurations of the first solid electrolyte layer 131 and the second solid electrolyte layer 132 may be the same or different. The filling rates of the first solid electrolyte layer 131 and the second solid electrolyte layer 132 are not particularly limited, but may be 85% or more, 90% or more, or 95% or more from the viewpoint of reducing the battery resistance.

[0055] 1.2.4. First negative electrode active material layer 141, second negative electrode active material layer 142 The first negative electrode active material layer 141 is laminated on one surface of the first solid electrolyte layer 131, and the second negative electrode active material layer 142 is laminated on the other surface of the second solid electrolyte layer 132. The configurations that can be adopted by the first negative electrode active material layer 141 and the second negative electrode active material layer 142 are similar to the configurations that can be adopted by the negative electrode active material layer 40, so a description thereof will be omitted here. However, the configurations of the first negative electrode active material layer 141 and the second negative electrode active material layer 142 may be the same or different. The filling rate of the first negative electrode active material layer 141 and the second negative electrode active material layer 142 is not particularly limited as long as it is less than 80%, but may be, for example, 70% or less, 60% or less, 30% or more, or 40% or more.

[0056] 1.2.5. First negative electrode current collector 151, second negative electrode current collector 152 The first negative electrode current collector 151 is laminated on one surface of the first negative electrode active material layer 141, and the second negative electrode current collector 152 is laminated on the other surface of the second negative electrode active material layer 142. The configurations that can be adopted by the first negative electrode current collector 151 and the second negative electrode current collector 152 are similar to the configurations that can be adopted by the negative electrode current collector 50, and therefore a description thereof will be omitted here. However, the configurations of the first negative electrode current collector 151 and the second negative electrode current collector 152 may be the same or different.

[0057] 1.2.6. Manufacturing method of the all-solid-state battery 200 Since the all-solid-state battery 200 is a subordinate concept of the all-solid-state battery 100, the manufacturing method of the all-solid-state battery 100 described above may be appropriately adopted. On the other hand, the all-solid-state battery 200 is characterized in that the filling rate of the first negative electrode active material layer 141 and the second negative electrode active material layer 142 is less than 80%. From the viewpoint of reducing the battery resistance, it is considered that the filling rates of the first positive electrode active material layer 121, the second positive electrode active material layer 122, the first solid electrolyte layer 131, and the second solid electrolyte layer 132 are made larger than the filling rates of the first negative electrode active material layer 141 and the second negative electrode active material layer 142. From the viewpoint of efficiently manufacturing such an all-solid-state battery 200, a manufacturing method 2000 described later may be adopted.

[0058] 1.3.Effects As described in the above embodiment, the all-solid-state battery of the present disclosure is characterized in that the filling rate of the negative electrode active material layer is less than 80%. The negative electrode active material layer 40 itself can absorb the volume change of the negative electrode active material due to charging and discharging, so that the expansion of the all-solid-state battery can be suppressed. In particular, when Si or a Si alloy, which has a large volume change due to charging and discharging, is used as the negative electrode active material, a remarkable effect is achieved. In addition, the all-solid-state battery of the present disclosure may have a filling rate of the positive electrode active material layer and the solid electrolyte layer of 85% or more from the viewpoint of reducing the battery resistance. Thus, the all-solid-state battery of the present disclosure includes a form in which the filling rates of the positive electrode active material layer and the solid electrolyte layer are larger than the filling rate of the negative electrode active material layer.

[0059] 2. Manufacturing method of all-solid-state batteries The manufacturing method of the all-solid-state battery of the present disclosure will be described with reference to manufacturing methods 1000 and 2000 of the all-solid-state battery, which are one embodiment.

[0060] 2.1. Manufacturing method of all-solid-state battery 1000 The manufacturing method 1000 of the all-solid-state battery is a method for efficiently manufacturing the all-solid-state battery 100. The manufacturing method 1000 of the all-solid-state battery includes a negative electrode fabrication step S1 in which the negative electrode active material layer 40 and the negative electrode current collector 50 are laminated to obtain a negative electrode, a positive electrode-solid electrolyte layer laminate fabrication step S2 in which the positive electrode active material layer 20 and the solid electrolyte layer 30 are laminated in this order on at least one surface of the positive electrode current collector 10 to obtain a positive electrode-solid electrolyte layer laminate, and a lamination step S3 in which the positive electrode-solid electrolyte layer laminate and the negative electrode are laminated so that the negative electrode active material layer 40 is disposed on the surface of the solid electrolyte layer 30, and the negative electrode active material layer contains a negative electrode active material, and the filling rate of the negative electrode active material layer is less than 80%. A flowchart of the manufacturing method 1000 of the all-solid-state battery is shown in FIG. 3.

[0061] 3, the order of carrying out the negative electrode fabrication step S1 and the positive electrode-solid electrolyte layer laminate fabrication step S2 is not limited, and one of them may be carried out first, or they may be carried out in parallel. The lamination step S3 is carried out after the negative electrode fabrication step S1 and the positive electrode-solid electrolyte layer laminate fabrication step S2.

[0062] 2.1.1. Negative electrode preparation process S1 The negative electrode preparation step S1 is a step of laminating the negative electrode active material layer 40 and the negative electrode current collector 50 to obtain a negative electrode.

[0063] The method for producing the negative electrode is not particularly limited. For example, the negative electrode can be produced by a dry method or a wet method. The method for producing the negative electrode by a dry method is not particularly limited, but the following method can be mentioned, for example. First, the materials constituting the negative electrode active material layer 40 are mixed and pressed at a predetermined pressure to form the negative electrode active material layer 40. Then, the negative electrode current collector 50 is laminated on the surface of the negative electrode active material layer 40 to obtain the negative electrode.

[0064] The method for producing the negative electrode by the wet method is not particularly limited, but may be, for example, the following method: After mixing the material constituting the negative electrode active material layer 40 with a predetermined organic solvent to form a slurry, the slurry is applied to the negative electrode current collector 50 and dried to obtain the negative electrode.

[0065] The method of applying the slurry is not particularly limited, and includes common methods such as doctor blade method, die coating method, gravure coating method, spray coating method, electrostatic coating method, bar coating method, etc. The method of drying the slurry is not particularly limited, and for example, the slurry may be heated to a temperature range of 50° C. to 200° C. The drying atmosphere may be set to an inert atmosphere or a reduced pressure atmosphere.

[0066] Here, in the negative electrode preparation step S1, the packing rate of the negative electrode active material layer 40 may be adjusted to a desired packing rate. However, it is necessary to adjust the packing rate of the negative electrode active material layer 40 to less than 80%. For example, the packing rate of the negative electrode active material layer 40 may be adjusted to a desired packing rate by pressing the negative electrode or the negative electrode active material layer 40. From the viewpoint of efficiency, after the negative electrode is formed, the negative electrode may be pressed to adjust the packing rate of the negative electrode active material layer 40 to a desired packing rate.

[0067] The pressing method is not particularly limited, but may be, for example, plate pressing. The surface pressure applied during plate pressing may be, for example, 1 MPa or more and 50 MPa or less.

[0068] 2.1.2. Positive electrode-solid electrolyte layer laminate process S2 The positive electrode-solid electrolyte layer laminate step S2 is a step of laminating a positive electrode active material layer 20 and a solid electrolyte layer 30 in this order on at least one surface of a positive electrode current collector 10 to obtain a positive electrode-solid electrolyte layer laminate.

[0069] The method for producing the positive electrode-solid electrolyte layer laminate is not particularly limited. For example, the positive electrode-solid electrolyte layer laminate can be produced by a dry or wet method. The method for producing the positive electrode-solid electrolyte layer laminate by a dry method is not particularly limited, but the following method can be mentioned, for example. First, the materials constituting the positive electrode active material layer 20 are mixed and pressed at a predetermined pressure to form the positive electrode active material layer 20. The solid electrolyte layer 30 is formed by the same method. Then, the positive electrode active material layer 20 and the solid electrolyte layer 30 are laminated in this order on at least one surface of the positive electrode current collector 10 to obtain the positive electrode-solid electrolyte layer laminate.

[0070] The method for producing the cathode-solid electrolyte layer laminate by the wet method is not particularly limited, but for example, the following method can be mentioned. After mixing the material constituting the cathode active material layer 20 with a predetermined organic solvent to form a slurry, the slurry is applied to at least one surface of the cathode current collector 10 and dried. As a result, a laminate in which the cathode active material layer 20 is laminated on at least one surface of the cathode current collector 10 is obtained. Next, after mixing the material constituting the solid electrolyte layer 30 with a predetermined organic solvent to form a slurry, the slurry is applied to a substrate and dried to form the solid electrolyte layer 30. Then, the solid electrolyte layer 30 is transferred to the surface of the cathode active material layer 20 to obtain the cathode-solid electrolyte layer laminate. Alternatively, the cathode-solid electrolyte layer laminate may be obtained by directly applying a slurry containing the material constituting the solid electrolyte layer 30 to the surface of the cathode active material layer 20 and drying it. The application method and drying temperature of the slurry are the same as those described above, so the explanation will be omitted here.

[0071] Here, in the positive electrode-solid electrolyte layer laminate preparation step S2, the filling rate of the positive electrode active material layer 20 may be adjusted to 85% or more. In addition, the filling rate of the solid electrolyte layer may be adjusted to 85% or more. For example, the positive electrode active material layer 20 and the solid electrolyte layer 30 may be pressed individually or in a laminated state (for example, in the state of a positive electrode-solid electrolyte layer laminate) to adjust the filling rate of the positive electrode active material layer 20 and the solid electrolyte layer 30 to 85% or more. From the viewpoint of efficiency, after forming the positive electrode-solid electrolyte layer laminate, the positive electrode-solid electrolyte layer laminate may be pressed to adjust the filling rate of the positive electrode active material layer 20 and the solid electrolyte layer 30 to 85% or more.

[0072] The pressing method is not particularly limited, but examples thereof include roll pressing and plate pressing. The linear pressure applied during roll pressing may be, for example, 1 t / cm or more and 4 t / cm or less. The gap between the rolls may be, for example, 0.1 mm or more and 0.3 mm or less. The surface pressure applied during plate pressing may be, for example, 400 MPa or more and 1900 MPa or less.

[0073] 2.1.3.Lamination process S3 The lamination step S3 is a step of laminating the positive electrode-solid electrolyte layer laminate and the negative electrode such that the negative electrode active material layer 40 is disposed on the surface of the solid electrolyte layer 30. In this manner, the all-solid-state battery 100 can be obtained.

[0074] The method of laminating the positive electrode-solid electrolyte layer laminate and the negative electrode is not particularly limited, and the positive electrode-solid electrolyte layer laminate and the negative electrode may simply be laminated to obtain the all-solid-state battery 100. In this case, from the viewpoint of reducing the contact resistance of each electrode layer, the all-solid-state battery 100 may be restrained and a restraining pressure toward the inside in the lamination direction may be applied. The restraining pressure is not particularly limited, but may be, for example, 0.5 MPa or more or 50 MPa or less. In addition, the obtained all-solid-state battery 100 may be pressed with a predetermined pressure, but attention must be paid to changes in the filling rate.

[0075] 2.2. Manufacturing method of all-solid-state batteries 2000 The manufacturing method 2000 of the all-solid-state battery is a method for efficiently manufacturing the all-solid-state battery 200. The manufacturing method 2000 of the all-solid-state battery includes a first negative electrode fabrication process S11a of laminating a first negative electrode active material layer 141 and a first negative electrode current collector 151 to obtain a first negative electrode, a second negative electrode fabrication process S11b of laminating a second negative electrode active material layer 152 and a second negative electrode current collector 152 to obtain a second negative electrode, and a positive electrode-solid electrode fabrication process S11c of laminating a first positive electrode active material layer 121 and a first solid electrolyte layer 131 in this order on one surface of a positive electrode current collector 110, and a second positive electrode active material layer 122 and a second solid electrolyte layer 132 in this order on the other surface of the positive electrode current collector 110 to obtain a positive electrode-solid electrode fabrication process S11d of laminating a first negative electrode active material layer 141 and a first negative electrode current collector 151 to obtain a first negative electrode, and a lamination step S13 of laminating the positive electrode-solid electrolyte layer laminate, the first negative electrode, and the second negative electrode such that the first negative electrode active material layer 121 is disposed on the surface of the first solid electrolyte layer 131 and the second negative electrode active material layer 122 is disposed on the surface of the second solid electrolyte layer 132, the first negative electrode active material layer 141 and the second negative electrode active material layer 142 contain a negative electrode active material, and the filling rate of the first negative electrode active material layer 141 and the second negative electrode active material layer 142 is less than 80%. A flowchart of the manufacturing method 2000 of an all-solid-state battery is shown in FIG. 4.

[0076] 4, the order of performing the first negative electrode fabrication step S11a, the second negative electrode fabrication step S11b, and the positive electrode-solid electrolyte layer laminate fabrication step S12 is not limited, and any one of them may be performed first, or they may be performed in parallel. The lamination step S13 is performed after the first negative electrode fabrication step S11a, the second negative electrode fabrication step S11b, and the positive electrode-solid electrolyte layer laminate fabrication step S12.

[0077] 2.2.1. First negative electrode preparation step S11a and second negative electrode preparation step S11b The first negative electrode preparation step S11a is a step of laminating the first negative electrode active material layer 141 and the first negative electrode current collector 151 to obtain a first negative electrode. The second negative electrode preparation step S11b is a step of laminating the second negative electrode active material layer 152 and the second negative electrode current collector 152 to obtain a second negative electrode. The configurations that can be adopted in the first negative electrode preparation step S11a and the second negative electrode preparation step S11b are similar to the configurations that can be adopted in the negative electrode preparation step S1, so the explanation will be omitted here. However, the first negative electrode preparation step S11a and the second negative electrode preparation step S11b may be the same or different.

[0078] 2.2.2. Positive electrode-solid electrolyte layer laminate process S12 The positive electrode-solid electrolyte layer laminate step S12 is a step of laminating a first positive electrode active material layer 121 and a first solid electrolyte layer 131 in this order on one surface of the positive electrode current collector 110 (lamination method A), and laminating a second positive electrode active material layer 122 and a second solid electrolyte layer 132 in this order on the other surface of the positive electrode current collector 110 (lamination method B) to obtain a positive electrode-solid electrolyte layer laminate. The configurations that can be adopted by lamination methods A and B are similar to the configurations that can be adopted by the positive electrode-solid electrolyte layer laminate step S2, and therefore the explanations are omitted here. However, lamination methods A and B may be the same or different from each other.

[0079] 2.2.3. Lamination process S13 The lamination step S13 is a step of laminating the positive electrode-solid electrolyte layer laminate, the first negative electrode, and the second negative electrode such that the first negative electrode active material layer 121 is disposed on the surface of the first solid electrolyte layer 131, and the second negative electrode active material layer 122 is disposed on the surface of the second solid electrolyte layer 132. This makes it possible to obtain the all-solid-state battery 200. The configuration that can be adopted in the lamination step S13 is similar to the configuration that can be adopted in the lamination step S3, and therefore a description thereof will be omitted here.

[0080] 2.3.Effects As described in the above embodiment, the method for producing an all-solid-state battery according to the present disclosure is a method for efficiently producing an all-solid-state battery according to the present disclosure. In particular, from the viewpoint of reducing the battery resistance, it is considered to make the packing rate of the positive electrode active material layer and the solid electrolyte layer larger than the packing rate of the negative electrode active material layer. In such a case, an all-solid-state battery can be produced more efficiently.

[0081] In the conventional manufacturing method, a negative electrode active material layer, a solid electrolyte layer, and a positive electrode active material layer are laminated on at least one surface of a negative electrode current collector, and then the laminate is pressed to densify the positive electrode active material layer and the solid electrolyte layer. As a result, the packing rate of the negative electrode active material layer is almost the same as that of the positive electrode active material layer and the solid electrolyte layer. Since conventional all-solid-state batteries are manufactured by such a process, it is difficult to reduce the packing rate of the negative electrode active material layer, and battery expansion has been a problem.

[0082] The manufacturing method of the all-solid-state battery disclosed herein focuses on the packing rate of the negative electrode active material layer, which is one of the causes of battery expansion, and is based on findings obtained as a result of a fundamental review of conventional manufacturing methods in order to efficiently manufacture an all-solid-state battery in which the packing rate of the negative electrode active material layer is adjusted while the positive electrode active material layer and the solid electrolyte layer are densified. EXAMPLES

[0083] The present disclosure will now be further described with reference to examples.

[0084] [Fabrication of all-solid-state batteries] As described below, all-solid-state batteries of Examples 1 to 4 and Comparative Examples 1 to 3 were fabricated.

[0085] <Example 1> (Negative electrode manufacturing process) Negative electrode active material (Si) 18.6g, sulfide solid electrolyte (0.75Li 2 S 0.25P 2 S 517.6g of the active material (VGCF) and 2.4g of the conductive additive were collected in a container. Then, 1.9g of SBR as a binder diluted to 5wt% and DIBK (diisobutyl ketone) as a dispersion medium were added to the container so that the solid content of the paste was 31wt%. Using a kneading device, Filmix was used to knead these materials at a peripheral speed of 5m / s to 30m / s to prepare a negative electrode layer paste. Next, the obtained negative electrode active material layer paste was applied to a negative electrode current collector using a blade coating method with an applicator, and dried at 100°C for 30 minutes to obtain a negative electrode.

[0086] Next, the obtained negative electrode was pressed using a flat press. The pressing pressure was 1 MPa. The filling rate of the negative electrode active material layer was calculated using the negative electrode after pressing. The results are shown in Table 1.

[0087] (Positive electrode-solid electrolyte layer laminate manufacturing process) First, the positive electrode was prepared. 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 )80.0g, sulfide solid electrolyte (0.75Li 2 S 0.25P 2 S 5 9.4g of the binder (100g) and 2.0g of the conductive additive (VGCF) were collected in a container. Then, 45.7g of SBR as a binder diluted to 5wt% and DIBK (diisobutyl ketone) as a dispersion medium were added to the container so that the solid content of the paste was 69wt%. Using a kneading device, Filmix was used to knead these materials at a peripheral speed of 5m / s to 30m / s to prepare a positive electrode active material layer paste. Next, the obtained positive electrode active material layer paste was applied to both sides of a positive electrode current collector using a blade coating method with an applicator, and dried at 100°C for 30 minutes to obtain a positive electrode.

[0088] Next, the solid electrolyte layer was prepared. 2 S 0.25P 2 S 5These materials were put into a dispersion medium (heptane) so that the content of the binder was 95 wt% and the content of the butadiene-based binder was 5 wt%, and the materials were subjected to ultrasonic treatment for 5 minutes using an ultrasonic homogenizer to obtain a solid electrolyte layer slurry. Next, the obtained solid electrolyte layer paste was applied to a substrate (aluminum foil) using a blade coating method with an applicator, and dried at 100°C for 30 minutes to obtain a solid electrolyte layer.

[0089] Then, the solid electrolyte layer was transferred to both sides of the positive electrode using a pressure of 20 kN. The obtained positive electrode-solid electrolyte layer laminate was pressed using a roll press. The press line pressure was 4 ton / cm. The gap between the rolls was 100 μm. In addition, the filling rate of the positive electrode active material layer and the solid electrolyte layer was calculated using the positive electrode-solid electrolyte layer laminate after pressing. The results are shown in Table 1.

[0090] (Lamination process) The negative electrode and positive electrode-solid electrolyte layer laminates were laminated, and tabs were attached to the respective current collectors, and then the laminate was sealed using a laminate sheet. Thereafter, the battery was restrained under a pressure of 20 MPa to obtain the all-solid-state battery of Example 1.

[0091] <Example 2> An all-solid-state battery of Example 2 was produced in the same manner as in Example 1, except that in the negative electrode production step, the pressing surface pressure of the plate press was changed to 5 MPa.

[0092] <Example 3> An all-solid-state battery of Example 3 was produced in the same manner as in Example 1, except that in the negative electrode production step, the pressing surface pressure of the plate press was changed to 20 MPa.

[0093] <Example 4> An all-solid-state battery of Example 4 was produced in the same manner as in Example 1, except that in the negative electrode production step, the pressing surface pressure of the plate press was changed to 50 MPa.

[0094] <Comparative Example 1> (Negative electrode manufacturing process) Anode active material (Si) 18.6g, sulfide solid electrolyte (0.75Li 2 S 0.25P 2 S 5 17.6g of the active material (VGCF) and 2.4g of the conductive additive were collected in a container. Then, 1.9g of SBR as a binder diluted to 5wt% and DIBK (diisobutyl ketone) as a dispersion medium were added to the container so that the solid content of the paste was 31wt%. Using a kneading device, Filmix was used to knead these materials at a peripheral speed of 5m / s to 30m / s to prepare a negative electrode layer paste. Next, the obtained negative electrode active material layer paste was applied to a negative electrode current collector using a blade coating method with an applicator, and dried at 100°C for 30 minutes to obtain a negative electrode.

[0095] (Positive electrode manufacturing process) Cathode active material (LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 )80.0g, sulfide solid electrolyte (0.75Li 2 S 0.25P 2 S 5 9.4g of the binder (100g) and 2.0g of the conductive additive (VGCF) were collected in a container. Then, 45.7g of SBR as a binder diluted to 5wt% and DIBK (diisobutyl ketone) as a dispersion medium were added to the container so that the solid content of the paste was 69wt%. Using a kneading device, Filmix was used to knead these materials at a peripheral speed of 5m / s to 30m / s to prepare a positive electrode active material layer paste. Next, the obtained positive electrode active material layer paste was applied to both sides of a positive electrode current collector using a blade coating method with an applicator, and dried at 100°C for 30 minutes to obtain a positive electrode.

[0096] (Solid electrolyte layer production process) Sulfide solid electrolyte (0.75Li 2 S 0.25P 2 S 5These materials were put into a dispersion medium (heptane) so that the content of the binder was 95 wt% and the content of the butadiene-based binder was 5 wt%, and the materials were subjected to ultrasonic treatment for 5 minutes using an ultrasonic homogenizer to obtain a solid electrolyte layer slurry. Next, the obtained solid electrolyte layer paste was applied to a substrate (aluminum foil) using a blade coating method with an applicator, and dried at 100°C for 30 minutes to obtain a solid electrolyte layer.

[0097] (Lamination process) A solid electrolyte layer and a positive electrode were transferred in this order to both sides of the obtained negative electrode using a pressure of 20 kN. The obtained laminate was pressed using a roll press. The press line pressure was 1 ton / cm. The gap between the rolls was 200 μm. In addition, the packing ratios of the negative electrode active material layer, the positive electrode active material layer, and the solid electrolyte layer were calculated using the laminate after pressing. The results are shown in Table 1.

[0098] Then, after attaching a tab to each current collector, the laminate was sealed with a laminate sheet, and the battery was then restrained under a pressure of 20 MPa to obtain the all-solid-state battery of Comparative Example 1.

[0099] <Comparative Example 2> An all-solid-state battery of Comparative Example 2 was produced in the same manner as in Comparative Example 1, except that in the lamination process, the press line pressure of the roll press machine was changed to 2 ton / cm and the gap between the rolls was changed to 150 μm.

[0100] <Comparative Example 3> An all-solid-state battery of Comparative Example 3 was produced in the same manner as in Comparative Example 1, except that in the lamination process, the press line pressure of the roll press machine was changed to 4 ton / cm and the gap between the rolls was changed to 100 μm.

[0101] [evaluation]

[0102] A pressure sensor and a displacement sensor were attached to the restraining tool of the fabricated all-solid-state battery, and these sensors were connected to an NR600 data logger (manufactured by KEYENCE Corporation). Next, the all-solid-state battery was subjected to 0.1C CCCV charge and discharge in the range of an upper limit voltage of 4.05V to a lower limit voltage of 2.5V. Here, the design capacity of the all-solid-state battery was set to 0.3Ah. From the obtained results, the restraining pressure change and the film thickness change of the all-solid-state battery were calculated based on the following formula. The results are shown in Table 1. Confinement pressure change (ΔMPa / Ah) = Pressure change during the 1st cycle (MPa) / Charge capacity during the 1st cycle (Ah) Change in film thickness (Δμm / Ah) = change in film thickness during the 1st cycle (MPa) / charge capacity during the 1st cycle (Ah)

[0103] [Table 1]

[0104] [result] In Examples 1 to 4, the values ​​of the confining pressure change and the film thickness change were smaller than those in Comparative Examples 1 to 3. Therefore, in Examples 1 to 4, the expansion of the battery could be suppressed. In addition, when focusing on the packing rate of the negative electrode active material layer, the packing rates in Examples 1 to 4 were less than 80%, whereas the packing rates in Comparative Examples 1 to 3 were 80% or more. The values ​​of the confining pressure change in Examples 1 to 4 were 0.8 MPa / Ah or less, and the values ​​of the film thickness change were 30 μm / Ah or less. In contrast, the values ​​of the confining pressure change in Comparative Examples 1 to 3 were greater than 0.8 MPa / Ah, and the values ​​of the film thickness change were greater than 30 μm / Ah, which were values ​​that raised concerns about the deterioration of cycle characteristics due to cracking or peeling of the electrode layer in the battery. From the above, it is considered that the packing rate of the negative electrode active material being less than 80% can also suppress the deterioration of cycle characteristics due to cracking or peeling of the electrode layer in the battery. [Explanation of symbols]

[0105] 10 Positive electrode current collector 20 Cathode active material layer 30 Solid electrolyte layer 40 Negative electrode active material layer 50 Negative electrode current collector 110 Positive electrode current collector 121 First positive electrode active material layer 122 Second positive electrode active material layer 131 First solid electrolyte layer 132 Second solid electrolyte layer 141 First negative electrode active material layer 142 Second negative electrode active material layer 151 First negative electrode current collector 152 Second negative electrode current collector 100, 200 All-solid-state battery

Claims

1. a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode current collector are laminated in this order on at least one surface of a positive electrode current collector; The negative electrode active material layer contains a negative electrode active material, the negative electrode active material is Si or a Si alloy, The filling rate of the solid electrolyte layer is 95% or more, a packing rate of the negative electrode active material layer relative to a packing rate of the solid electrolyte layer is 40% or more and 68% or less.

2. The all-solid-state battery as described in claim 1, wherein the filling rate of the negative electrode active material layer is a ratio of 40% or more to 57% or less with respect to the filling rate of the solid electrolyte layer.

3. The all-solid-state battery as described in claim 1, wherein the filling rate of the negative electrode active material layer is a ratio of 40% or more to 47% or less with respect to the filling rate of the solid electrolyte layer.

4. The negative electrode active material layer contains a binder. The all-solid-state battery according to any one of claims 1 to 3.

5. a negative electrode preparation step of laminating a negative electrode active material layer and a negative electrode current collector to obtain a negative electrode; a positive electrode-solid electrolyte layer laminate fabrication step of laminating a positive electrode active material layer and a solid electrolyte layer in this order on at least one surface of a positive electrode current collector to obtain a positive electrode-solid electrolyte layer laminate; a lamination step of laminating the positive electrode-solid electrolyte layer laminate and the negative electrode such that the negative electrode active material layer is disposed on a surface of the solid electrolyte layer, The negative electrode active material layer contains a negative electrode active material, the negative electrode active material is Si or a Si alloy, The filling rate of the solid electrolyte layer is 95% or more, a packing rate of the negative electrode active material layer relative to a packing rate of the solid electrolyte layer is 40% or more and 68% or less.

6. The method for manufacturing an all-solid-state battery described in claim 5, wherein the filling rate of the negative electrode active material layer is a ratio of 40% or more to 57% or less with respect to the filling rate of the solid electrolyte layer.

7. The method for manufacturing an all-solid-state battery described in claim 5, wherein the filling rate of the negative electrode active material layer is 40% or more and 47% or less relative to the filling rate of the solid electrolyte layer.

8. The negative electrode active material layer contains a binder. The method for producing the all-solid-state battery according to any one of claims 5 to 7.

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