All-solid battery

Abstract

To provide an all-solid battery with improved capacity retention.SOLUTION: An all-solid battery includes a positive electrode active material layer 10, a solid electrolyte layer 20, and a negative electrode active material layer 30 in this order. An insulating member 40 in contact with an outer side surface of the positive electrode active material layer 10 or an outer peripheral part of a surface of the positive electrode active material layer 10 on the solid electrolyte layer 20 side is further provided. The arithmetic roughness Ra of a surface of the insulating member 40 on the negative electrode active material layer 30 side that is measured in accordance with JIS B0601:2013 is 0.10 μm or more and 10.0 μm or less.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an all-solid-state battery. [Background technology]

[0002] There is an all-solid-state battery that has a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer.

[0003] Patent Document 1 describes a method for manufacturing an all-solid-state battery, with the aim of providing a method for manufacturing an all-solid-state battery capable of improving adhesion between a current collecting layer and a composite layer, including the steps of: preparing a first current collecting layer having an adhesive layer; stacking the first composite layer, a solid electrolyte layer, a second composite layer, and a second current collecting layer to prepare a laminate in which the surface of the first composite layer has a convex shape; and stacking the adhesive layer of the first current collecting layer on the first composite layer of the laminate, followed by pressing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-080519 Summary of the Invention [Problem to be solved by the invention]

[0005] According to the investigations of the present inventors, it has become clear that in an all-solid-state battery having an insulating member, when charge-discharge cycles are repeated, the capacity retention rate relative to the initial discharge capacity may decrease in some cases.

[0006] The present invention provides an all-solid-state battery with an improved capacity retention rate. [Means for solving the problem]

[0007] The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result, have found that an all-solid-state battery can improve capacity retention, the all-solid-state battery including a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order, and further including an insulating member in contact with the outer surface of the positive electrode active material layer or the outer periphery of the surface of the positive electrode active material layer facing the solid electrolyte layer, wherein the surface of the insulating member facing the negative electrode active material layer has an arithmetic mean roughness Ra of 0.10 μm or more and 10.0 μm or less, as measured in accordance with JIS B0601:2013, and has completed the present invention.

[0008] According to the present invention, the following all-solid-state battery is provided.

[0009] [1] a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order; the positive electrode active material layer further includes an insulating member in contact with an outer surface of the positive electrode active material layer or an outer periphery of a surface of the positive electrode active material layer on the side of the solid electrolyte layer, An all-solid-state battery, wherein the surface of the insulating member facing the negative electrode active material layer has an arithmetic mean roughness Ra of 0.10 μm or more and 10.0 μm or less, as measured in accordance with JIS B0601:2013. [2] The area of ​​the overlapping portion between the surface of the insulating member on the negative electrode active material layer side and at least one of the solid electrolyte layer and the negative electrode active material layer is defined as S A , the area of ​​the part surrounded by the inner surface of the insulating member is S B Then, (S A / S B ) × 100(%) is 0.1% or more and 50.0% or less. [3] The all-solid-state battery according to [1] or [2], wherein the surface of the insulating member facing the negative electrode active material layer has a maximum height roughness Rz of 0.50 μm or more and 20.0 μm or less, as measured in accordance with JIS B0601:2013. [4] the insulating member is in contact with the outer surface of the positive electrode active material layer, The all-solid-state battery according to any one of [1] to [3], wherein the thickness of the insulating member is smaller than the thickness of the positive electrode active material layer. [5] the insulating member is in contact with the outer surface of the positive electrode active material layer, The all-solid-state battery according to any one of [1] to [3], wherein the thickness of the insulating member is equal to or greater than the thickness of the positive electrode active material layer and is equal to or less than the sum of the thickness of the positive electrode active material layer and the thickness of the solid electrolyte layer. [6] the insulating member is in contact with the outer surface of the positive electrode active material layer, The all-solid-state battery according to any one of [1] to [3], wherein the thickness of the insulating member is greater than the sum of the thickness of the positive electrode active material layer and the thickness of the solid electrolyte layer. [7] the insulating member contacts an outer periphery of a surface of the positive electrode active material layer facing the solid electrolyte layer, The all-solid-state battery according to any one of [1] to [3], wherein the thickness of the insulating member is smaller than the thickness of the solid electrolyte layer. [8] the insulating member contacts an outer periphery of a surface of the positive electrode active material layer facing the solid electrolyte layer, The all-solid-state battery according to any one of [1] to [3], wherein the thickness of the insulating member is equal to or greater than the thickness of the solid electrolyte layer. [9] The all-solid-state battery according to any one of [1] to [8], wherein the negative electrode active material layer contains one or more negative electrode active materials selected from the group consisting of carbon materials, lithium-based metal materials, Si-based materials, and conductive polymer materials.

[10] The all-solid-state battery according to any one of [1] to [9], wherein the solid electrolyte layer contains one or more solid electrolyte materials selected from the group consisting of an oxide-based solid electrolyte material, a sulfide-based solid electrolyte material, a polymer-based solid electrolyte material, and a halogen-based solid electrolyte material.

[11] The all-solid-state battery according to any one of [1] to

[10] , wherein the insulating member contains one or more materials selected from the group consisting of insulating materials and materials containing insulating metal oxides. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide an all-solid-state battery with an improved capacity retention rate. [Brief explanation of the drawings]

[0011] [Figure 1] 1A and 1B are a schematic plan view and a schematic cross-sectional view illustrating an example of an all-solid-state battery according to an embodiment of the present invention. [Figure 2] FIG. 1 is a schematic cross-sectional view illustrating an example of an all-solid-state battery according to an embodiment of the present invention. [Figure 3] FIG. 1 is a schematic cross-sectional view illustrating an example of an all-solid-state battery according to an embodiment of the present invention. [Figure 4] FIG. 1 is a schematic cross-sectional view illustrating an example of an all-solid-state battery according to an embodiment of the present invention. [Figure 5] FIG. 1 is a schematic cross-sectional view illustrating an example of an all-solid-state battery according to an embodiment of the present invention. [Figure 6] FIG. 1 is a schematic cross-sectional view illustrating an example of an all-solid-state battery according to an embodiment of the present invention. [Figure 7] FIG. 1 is a schematic cross-sectional view illustrating an example of an all-solid-state battery according to an embodiment of the present invention. [Figure 8] FIG. 1 is a schematic cross-sectional view illustrating an example of an all-solid-state battery according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. To avoid complexity, when there are multiple identical components in the same drawing, only one of them may be labeled with a symbol, and not all of them. The drawings are for illustrative purposes only, and the shapes and dimensional ratios of the components in the drawings do not necessarily correspond to the actual products.

[0013] In this embodiment, "A to B" indicating a numerical range means A or more and B or less unless otherwise specified.

[0014] <All-solid-state battery> The all-solid-state battery of this embodiment has a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order, and further has an insulating member in contact with the outer surface of the positive electrode active material layer or the outer periphery of the surface of the positive electrode active material layer facing the solid electrolyte layer, and the arithmetic mean roughness Ra of the surface of the insulating member facing the negative electrode active material layer, measured in accordance with JIS B0601:2013, is 0.10 μm or more and 10.0 μm or less.

[0015] According to the investigations of the present inventors, it has become clear that in an all-solid-state battery having an insulating member, if the surface roughness of the surface of the insulating member is too small or too large, the cell resistance increases, and as a result, lithium that does not contribute to charge and discharge is likely to be generated, and the capacity retention rate during charge and discharge cycling may decrease.

[0016] As a result of further investigations based on the above findings, the present inventors have found that an all-solid-state battery can improve capacity retention, the all-solid-state battery having a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order, and further having an insulating member in contact with the outer surface of the positive electrode active material layer or the outer periphery of the surface of the positive electrode active material layer facing the solid electrolyte layer, wherein the surface of the insulating member facing the negative electrode active material layer has an arithmetic mean roughness Ra of 0.10 μm or more and 10.0 μm or less, as measured in accordance with JIS B0601:2013, and has completed the present invention.

[0017] In the all-solid-state battery of this embodiment, the arithmetic mean roughness Ra of the surface of the insulating member facing the negative electrode active material layer, measured in accordance with JIS B0601:2013, is from 0.10 μm to 10.0 μm, preferably from 0.20 μm to 9.0 μm, more preferably from 0.40 μm to 8.0 μm, even more preferably from 0.50 μm to 7.0 μm, even more preferably from 0.70 μm to 6.0 μm, even more preferably from 0.90 μm to 4.0 μm, and even more preferably from 1.0 μm to 3.0 μm, from the viewpoint of further improving the capacity retention rate. By setting the arithmetic mean roughness Ra of the surface of the insulating member facing the negative electrode active material layer within the above range, the cell resistance can be further reduced, the generation of lithium that does not contribute to charge and discharge can be further suppressed, and the capacity retention rate can be further improved.

[0018] In the all-solid-state battery of this embodiment, the surface of the insulating member facing the negative electrode active material layer has a maximum roughness in height Rz, measured in accordance with JIS B0601:2013, of preferably 0.50 μm to 20.0 μm, more preferably 0.80 μm to 18.0 μm, even more preferably 1.3 μm to 15.0 μm, even more preferably 2.0 μm to 12.0 μm, even more preferably 4.0 μm to 10.0 μm, and even more preferably 5.5 μm to 9.0 μm, from the viewpoint of further improving the capacity retention rate. By setting the maximum roughness in height Rz of the surface of the insulating member facing the negative electrode active material layer within the above range, the cell resistance can be further reduced, the generation of lithium that does not contribute to charge and discharge can be further suppressed, and the capacity retention rate can be further improved.

[0019] In the all-solid-state battery of this embodiment, examples of a method for adjusting the arithmetic mean roughness Ra and maximum height roughness Rz of the surface of the insulating member on the negative electrode active material layer side, as measured in accordance with JIS B0601:2013, include a method of using commercially available insulating members having different surface arithmetic mean roughness Ra and maximum height roughness Rz, and a method of imparting different surface roughness to the surface of a commercially available insulating member by adjusting treatment conditions such as sandblasting, shot blasting, matte finish, polishing, etching, etc.

[0020] In the all-solid-state battery of this embodiment, the arithmetic mean roughness Ra and maximum height roughness Rz of the surface of the insulating member on the negative electrode active material layer side can be measured, for example, using a one-shot 3D shape measuring device in accordance with JIS B0601:2013.

[0021] In the all-solid-state battery of this embodiment, the area of ​​the overlapping portion between the surface of the insulating member on the negative electrode active material layer side and at least one of the solid electrolyte layer and the negative electrode active material layer is S A , the area of ​​the part surrounded by the inner surface of the insulating member is S B Then, (S A / S BFrom the viewpoint of further improving the capacity retention rate, the value of (S) × 100 is preferably 0.1% or more, more preferably 0.3% or more, even more preferably 1.0% or more, even more preferably 2.0% or more, even more preferably 4.0% or more, even more preferably 8.0% or more, and even more preferably 10.0% or more, and from the viewpoint of further improving the energy density, it is preferably 50.0% or less, more preferably 40.0% or less, even more preferably 35.0% or less, even more preferably 30.0% or less, even more preferably 25.0% or less, even more preferably 20.0% or less, and even more preferably 15.0% or less. A / S B By making the value of (S ) × 100 equal to or greater than the lower limit, the cell resistance can be further reduced, and the generation of lithium that does not contribute to charge and discharge can be further suppressed, thereby further improving the capacity retention rate. A / S B By making the value of (3)×100 equal to or less than the upper limit, the amount of negative electrode active material in the portion not facing the solid electrolyte layer can be further reduced, thereby further improving the energy density.

[0022] From these facts, in the all-solid-state battery of this embodiment, the area of ​​the overlapping portion between the surface of the insulating member on the negative electrode active material layer side and at least one of the solid electrolyte layer and the negative electrode active material layer is set to S A , the area of ​​the part surrounded by the inner surface of the insulating member is S B Then, (S A / S B From the viewpoint of further improving the performance balance between the capacity retention rate and the energy density, the value of (3) × 100 is preferably 0.1% or more and 50.0% or less, more preferably 0.3% or more and 40.0% or less, even more preferably 1.0% or more and 35.0% or less, even more preferably 2.0% or more and 30.0% or less, even more preferably 4.0% or more and 25.0% or less, even more preferably 8.0% or more and 20.0% or less, and even more preferably 10.0% or more and 15.0% or less.

[0023] FIG. 1 is a schematic plan view and a schematic cross-sectional view showing an example of an all-solid-state battery according to this embodiment. As shown in FIG. 1 , in this embodiment, an overlap portion 50 between the surface of the insulating member facing the negative electrode active material layer and at least one of the solid electrolyte layer and the negative electrode active material layer refers to the portion of the surface of the insulating member facing the negative electrode active material layer that overlaps with at least one of the solid electrolyte layer and the negative electrode active material layer in a plan view.

[0024] Hereinafter, an example of the structure of the all-solid-state battery according to this embodiment will be described with reference to the drawings.

[0025] FIG. 2 is a schematic cross-sectional view showing an example of the all-solid-state battery according to this embodiment. 2, the all-solid-state battery of this embodiment has a positive electrode active material layer 10, a solid electrolyte layer 20, and a negative electrode active material layer 30 in this order, and further has an insulating member 40 in contact with the outer surface of the positive electrode active material layer 10. This allows the outer surface of the positive electrode active material layer 10 to be covered with the insulating member 40, thereby further improving insulation properties.

[0026] FIG. 3 is a schematic cross-sectional view showing an example of the all-solid-state battery according to this embodiment. 3, the all-solid-state battery of this embodiment has a positive electrode active material layer 10, a solid electrolyte layer 20, and a negative electrode active material layer 30 in this order, and further has an insulating member 40 in contact with the outer periphery of the surface of the positive electrode active material layer 10 facing the solid electrolyte layer 20. This eliminates the need for the insulating member 40 to cover the outer surface of the positive electrode active material layer 10, and the thickness of the insulating member 40 can be reduced, thereby improving the weight and reducing costs.

[0027] FIG. 4 is a schematic cross-sectional view showing an example of the all-solid-state battery according to this embodiment. 4, the insulating member 40 contacts the outer surface of the positive electrode active material layer 10, and the thickness of the insulating member 40 is smaller than the thickness of the positive electrode active material layer 10. This allows the thickness of the insulating member 40 to be reduced, thereby improving the weight and reducing costs.

[0028] FIG. 5 is a schematic cross-sectional view showing an example of the all-solid-state battery according to this embodiment. 5, the insulating member 40 contacts the outer surface of the positive electrode active material layer 10, and the thickness of the insulating member 40 is equal to or greater than the thickness of the positive electrode active material layer 10 and equal to or less than the sum of the thickness of the positive electrode active material layer 10 and the thickness of the solid electrolyte layer 20. This allows the thickness of the insulating member 40 to be reduced while covering the outer surface of the positive electrode active material layer 10, thereby improving the balance between insulation properties, light weight, and cost.

[0029] FIG. 6 is a schematic cross-sectional view showing an example of the all-solid-state battery according to this embodiment. 6, the insulating member 40 contacts the outer surface of the positive electrode active material layer 10, and the thickness of the insulating member 40 is greater than the sum of the thickness of the positive electrode active material layer 10 and the thickness of the solid electrolyte layer 20. This allows the outer surface of the positive electrode active material layer 10 to be covered with the insulating member 40, thereby further improving insulation properties.

[0030] FIG. 7 is a schematic cross-sectional view showing an example of the all-solid-state battery according to this embodiment. 7, the insulating member 40 contacts the outer periphery of the surface of the positive electrode active material layer 10 on the side of the solid electrolyte layer 20, and the thickness of the insulating member 40 is smaller than the thickness of the solid electrolyte layer 20. This allows the thickness of the insulating member 40 to be reduced, thereby improving the weight and reducing costs.

[0031] FIG. 8 is a schematic cross-sectional view showing an example of the all-solid-state battery according to this embodiment. 8, the insulating member 40 contacts the outer periphery of the surface of the positive electrode active material layer 10 facing the solid electrolyte layer 20, and the thickness of the insulating member 40 is equal to or greater than the thickness of the solid electrolyte layer 20. This allows the thickness of the insulating member 40 to be smaller than when the insulating member 40 contacts the outer surface of the positive electrode active material layer 10, thereby improving the weight and reducing costs.

[0032] <Negative electrode active material layer 30> From the perspective of further improving battery performance, the negative electrode active material layer 30 of this embodiment preferably contains one or more negative electrode active materials selected from the group consisting of carbon materials such as graphite that occludes lithium, amorphous carbon, diamond-like carbon, fullerene, carbon nanotube, carbon nanohorn; lithium-based metal materials such as lithium metal and lithium alloy; Si-based materials such as Si, SiO2, SiO x (0 < x ≦ 2), Si-containing composite materials, etc.; and conductive polymer materials such as polyacene, polyacetylene, polypyrrole. More preferably, it contains a lithium-based metal material, and even more preferably, it contains lithium metal.

[0033] Since the cell resistance of the all-solid-state battery of this embodiment is reduced, even if the negative electrode active material layer 30 contains a lithium-based material, it is possible to suppress the generation of lithium that does not contribute to charge and discharge and the decrease in the capacity retention rate.

[0034] The negative electrode active material layer 30 of this embodiment preferably contains a metal foil, and more preferably contains a metal foil of lithium metal or lithium alloy. The metal foil may be a metal foil having a base material and further having a metal or alloy laminated thereon.

[0035] The negative electrode active material layer 30 of this embodiment may optionally contain a binder. Examples of the binder include fluororesins such as polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), and polyvinyl fluoride (PVF); conductive polymers such as polyanilines, polythiophenes, polyacetylenes, and polypyrroles; synthetic rubbers such as styrene-butadiene rubber (SBR), butadiene rubber (BR), chloroprene rubber (CR), isoprene rubber (IR), and acrylonitrile-butadiene rubber (NBR); and polysaccharides such as carboxymethyl cellulose (CMC), xanthan gum, guar gum, and pectin. One of these may be used alone, or two or more of them may be used in combination.

[0036] The negative electrode active material layer 30 of this embodiment may optionally contain a conductive assistant. Examples of the conductive additive include carbon fibers such as carbon nanofibers; carbon blacks such as acetylene black and ketjen black; and carbon materials such as activated carbon, mesoporous carbon, fullerenes, and carbon nanotubes. One of these may be used alone, or two or more may be used in combination.

[0037] From the viewpoint of further improving battery performance, the content of the negative electrode active material in the negative electrode active material layer 30 of this embodiment is preferably 70 parts by mass or more and 100 parts by mass or less, more preferably 80 parts by mass or more and 100 parts by mass or less, and even more preferably 90 parts by mass or more and 100 parts by mass or less, when the total amount of the negative electrode active material layer 30 is taken as 100 parts by mass.

[0038] The thickness of the negative electrode active material layer 30 of this embodiment is preferably 1 μm or more and 150 μm or less, more preferably 5 μm or more and 100 μm or less, and even more preferably 10 μm or more and 80 μm or less.

[0039] <Solid electrolyte layer 20> From the viewpoint of further improving battery performance, the solid electrolyte layer 20 of the present embodiment preferably contains one or more solid electrolyte materials selected from the group consisting of an oxide-based solid electrolyte material, a sulfide-based solid electrolyte material, a polymer-based solid electrolyte material, and a halogen-based solid electrolyte material, more preferably contains a sulfide-based solid electrolyte material, and even more preferably contains an argyrodite-based solid electrolyte material.

[0040] In the all-solid-state battery of this embodiment, the cell resistance is reduced, and therefore, even if the solid electrolyte layer 20 contains a lithium-based material, it is possible to prevent the generation of lithium that does not contribute to charge and discharge and the resulting decrease in the capacity retention rate.

[0041] Examples of oxide-based solid electrolyte materials include NASICON-type solid electrolyte materials such as LiTi2(PO4)3, LiZr2(PO4)3, and LiGe2(PO4)3; 0.5+x Li 0.5-3x) Perovskite-type solid electrolyte materials such as TiO3; Li2O-P2O5 materials, Li2O-P2O5-Li3N materials, etc. These may be used alone or in combination of two or more.

[0042] Examples of sulfide-based solid electrolyte materials include argyrodite-based solid electrolytes (Li6PS5X, Li 7-y PS 6-y X y (X=Cl,Br,I, y=0.0~1.8)), Li2S-P2S5 material, Li2S-SiS2 material, Li2S-GeS2 material, Li2S-Al2S3 material, Li2S-SiS2-Li3PO4 material, Li2S-P 2S5-GeS2 material, Li2S-Li2O-P2S5-SiS2 material, Li2S-GeS2-P2S5-SiS2 material, Li2S-SnS2-P2S5-SiS2 material, Li2S-P2S5-Li3N material, Li2S 2+X -P4S3 material, Li2S-P2S5-P4S3 material, etc. These may be used alone or in combination of two or more.

[0043] Examples of polymer-based solid electrolyte materials include polyether-based electrolyte materials such as polyethylene oxide, polypropylene oxide, ethylene oxide-propylene copolymer, and dimethylsiloxane-ethylene oxide copolymer; gel polymer electrolyte materials such as polyacrylonitrile, polyvinylidene fluoride, and vinylidene fluoride-hexafluoropropylene polymer; and polymer solid electrolyte materials using hyperbranched polymers. These may be used alone or in combination of two or more.

[0044] Examples of halogen-based solid electrolyte materials include LiTaOCl4, LiNbOCl4, and LiTa 0.9 Nb 0.1 Metal oxyhalide compounds such as OCl4, metal sulfur halide compounds such as Li2S-P2S5-LiI material, Li2S-P2S5-LiBr material, etc. These may be used alone or in combination of two or more.

[0045] From the viewpoint of further improving battery performance, the content of the solid electrolyte in the solid electrolyte layer 20 of the present embodiment is preferably 80 parts by mass or more and 100 parts by mass or less, more preferably 90 parts by mass or more and 100 parts by mass or less, and even more preferably 95 parts by mass or more and 100 parts by mass or less, when the total amount of the solid electrolyte layer 20 is taken as 100 parts by mass.

[0046] The thickness of the solid electrolyte layer 20 of this embodiment is preferably 1 μm or more and 150 μm or less, more preferably 5 μm or more and 100 μm or less, and even more preferably 10 μm or more and 80 μm or less.

[0047] <Cathode active material layer 10> From the viewpoint of further improving battery performance, the positive electrode active material layer 10 of this embodiment is preferably made of a composite oxide of lithium and a transition metal such as lithium-nickel composite oxide, lithium-cobalt composite oxide, lithium-manganese composite oxide, lithium-nickel-manganese composite oxide, lithium-nickel-cobalt composite oxide, lithium-nickel-aluminum composite oxide, lithium-nickel-cobalt-aluminum composite oxide, lithium-nickel-manganese-cobalt composite oxide, lithium-nickel-manganese-aluminum composite oxide, or lithium-nickel-cobalt-manganese-aluminum composite oxide; a transition metal sulfide such as TiS2, FeS, or MoS2; MnO, VO5, or VO 13 and transition metal oxides such as TiO2; and olivine-type lithium phosphate oxides, more preferably a composite oxide of lithium and a transition metal, and even more preferably a lithium-nickel-manganese-cobalt composite oxide.

[0048] The volume-based median diameter D of the positive electrode active material in the positive electrode active material layer 10 of this embodiment measured by a laser diffraction scattering method 50 is preferably 1 μm or more and 100 μm or less, more preferably 2 μm or more and 50 μm or less.

[0049] From the viewpoint of further improving battery performance, the content of the positive electrode active material in the positive electrode active material layer 10 of this embodiment is preferably 50 parts by mass or more and 90 parts by mass or less, more preferably 60 parts by mass or more and 80 parts by mass or less, and even more preferably 65 parts by mass or more and 75 parts by mass or less, when the total amount of the positive electrode active material layer 10 is taken as 100 parts by mass.

[0050] From the viewpoint of further improving battery performance, the positive electrode active material layer 10 of this embodiment preferably contains one or more conductive additives selected from the group consisting of carbon black, natural graphite, artificial graphite, and carbon nanotubes, and more preferably contains carbon nanotubes.

[0051] From the viewpoint of further improving battery performance, the content of the conductive additive in the positive electrode active material layer 10 of this embodiment is preferably 0.01 parts by mass or more and 15 parts by mass or less, more preferably 0.1 parts by mass or more and 10 parts by mass or less, and even more preferably 0.5 parts by mass or more and 8 parts by mass or less, when the total amount of the positive electrode active material layer 10 is taken as 100 parts by mass.

[0052] The positive electrode active material layer 10 of this embodiment preferably contains one or more binders selected from the group consisting of fluorine-based binders such as polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF); and aqueous binders, more preferably contains a fluorine-based binder, and even more preferably contains polyvinylidene fluoride.

[0053] The content of the binder in the positive electrode active material layer 10 of this embodiment is preferably 0.01 parts by mass or more and 15 parts by mass or less, and more preferably 0.1 parts by mass or more and 10 parts by mass or less, when the total amount of the positive electrode active material layer 10 is 100 parts by mass.

[0054] The positive electrode active material layer 10 of this embodiment preferably contains a solid electrolyte. The type of solid electrolyte is not particularly limited, and may contain one or more solid electrolyte materials selected from the group consisting of oxide-based solid electrolyte materials, sulfide-based solid electrolyte materials, polymer-based solid electrolyte materials, and halogen-based solid electrolyte materials. However, it preferably contains the same solid electrolyte as the solid electrolyte contained in the solid electrolyte layer 20.

[0055] The content of the solid electrolyte in the positive electrode active material layer 10 of this embodiment is preferably 1 part by mass or more and 50 parts by mass or less, and more preferably 3 parts by mass or more and 30 parts by mass or less, when the total amount of the positive electrode active material layer 10 is 100 parts by mass.

[0056] The density of the positive electrode active material layer 10 of this embodiment is preferably 1.0 g / cm 3 More than 5.0g / cm 3 or less, more preferably 2.0 g / cm 3 More than 4.0g / cm 3 The following is the result.

[0057] The thickness of the positive electrode active material layer 10 of this embodiment is preferably 1 μm or more and 150 μm or less, more preferably 5 μm or more and 100 μm or less, and even more preferably 10 μm or more and 80 μm or less.

[0058] <Insulating member 40> From the viewpoint of further improving the capacity retention rate, the insulating member 40 of this embodiment preferably contains one or more materials selected from the group consisting of resin-based insulating materials such as polypropylene-based insulating materials, polyester-based insulating materials, polyimide-based insulating materials, vinyl chloride-based insulating materials, and acetate-based insulating materials; glass fiber-based insulating materials; butyl rubber-based insulating materials; and materials containing insulating metal oxides such as alumina, boehmite, magnesium oxide, and silicon dioxide, more preferably a resin-based insulating material, and even more preferably a polyester-based insulating material.

[0059] The form of the insulating member 40 of this embodiment is not particularly limited, but from the viewpoint of further improving productivity, it is preferably an insulating tape.

[0060] From the viewpoint of further improving the balance between insulation properties, light weight, and cost, the thickness of the insulating member 40 of the present embodiment is preferably 1 μm or more and 150 μm or less, more preferably 5 μm or more and 100 μm or less, and even more preferably 10 μm or more and 80 μm or less in the aspect of the all-solid-state battery shown in FIG. Moreover, from the viewpoint of further improving the balance between insulation properties, light weight, and cost, the thickness of the insulating member 40 of the present embodiment is preferably 1 μm or more and 300 μm or less, more preferably 5 μm or more and 200 μm or less, and even more preferably 10 μm or more and 160 μm or less in the aspect of the all-solid-state battery shown in FIG.

[0061] <Positive electrode current collector> The all-solid-state battery of this embodiment may further include a positive electrode current collector in a position in contact with the surface of the positive electrode active material layer 10 opposite to the solid electrolyte layer 20 side.

[0062] The positive electrode current collector may be formed of, for example, aluminum, stainless steel, nickel, titanium, or an alloy thereof. The positive electrode current collector may be in the form of, for example, a foil, a flat plate, or a mesh. The thickness of the positive electrode current collector is not particularly limited, but is, for example, 1 μm or more and 50 μm or less.

[0063] <Negative electrode current collector> The all-solid-state battery of this embodiment may further include a negative electrode current collector at a position in contact with the surface of the negative electrode active material layer 30 opposite to the solid electrolyte layer 20 side.

[0064] The negative electrode current collector may be formed of, for example, copper, stainless steel, nickel, titanium, or an alloy thereof. The negative electrode current collector may be in the form of, for example, a foil, a flat plate, or a mesh. The thickness of the negative electrode current collector is not particularly limited, but is, for example, 1 μm or more and 50 μm or less.

[0065] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention. [Example]

[0066] The embodiments of the present invention will be described in detail based on examples and comparative examples, but the present invention is not limited to the examples.

[0067] <Insulating materials> The surface of a 50 μm-thick polyester insulating tape was sandblasted (Hozan Corporation, SG-106) to impart various surface roughnesses by adjusting the particle size of the blasting agent and the processing time, resulting in insulating tapes 1 to 10 with different arithmetic mean roughness Ra and maximum height roughness Rz. The arithmetic mean roughness Ra and maximum height roughness Rz of the surfaces of insulating tapes 1 to 10 were measured using a one-shot 3D shape measuring machine (Keyence Corporation, VR-6000) in accordance with JIS B0601:2013.

[0068] Insulating tapes 1 to 10 used as insulating members in the production of the all-solid-state batteries of Examples 1 to 14 and Comparative Examples 1 and 2 are shown below. Insulating tape 1 (arithmetic mean surface roughness Ra: 0.10 μm, maximum height roughness Rz: 1.1 μm) Insulating tape 2 (arithmetic mean surface roughness Ra: 0.30 μm, maximum height roughness Rz: 1.6 μm) Insulating tape 3 (arithmetic mean surface roughness Ra: 0.80 μm, maximum height roughness Rz: 5.2 μm) Insulating tape 4 (arithmetic mean surface roughness Ra: 1.1 μm, maximum height roughness Rz: 6.2 μm) Insulating tape 5 (arithmetic mean surface roughness Ra: 1.9 μm, maximum height roughness Rz: 8.1 μm) Insulating tape 6 (arithmetic mean surface roughness Ra: 4.5 μm, maximum height roughness Rz: 8.8 μm) Insulating tape 7 (arithmetic mean surface roughness Ra: 7.7 μm, maximum height roughness Rz: 13.9 μm) Insulating tape 8 (arithmetic mean surface roughness Ra: 9.6 μm, maximum height roughness Rz: 15.8 μm) Insulating tape 9 (arithmetic mean surface roughness Ra: 0.05 μm, maximum height roughness Rz: 0.25 μm) Insulating tape 10 (arithmetic mean surface roughness Ra: 12.5 μm, maximum height roughness Rz: 22.5 μm)

[0069] <Fabrication of all-solid-state batteries> Example 1 Lithium nickel cobalt manganese oxide (Li(Ni 0.8 Co 0.1 Mn 0.1 70 parts by mass of )O2) was mixed with 25 parts by mass of Li6PS5Cl (argyrodite-based solid electrolyte) as a solid electrolyte, 3 parts by mass of polyvinylidene fluoride as a binder, and 2 parts by mass of single-walled carbon nanotubes as a conductive additive, and the mixture was dispersed in N-methyl-2-pyrrolidone to obtain a positive electrode slurry. The obtained positive electrode slurry was then applied to an aluminum positive electrode current collector with a thickness of 12 μm at a concentration of 15 mg / cm. 2 After drying, the mixture was pressed with a roll press at a linear pressure of 5.0 ton / cm to obtain a positive electrode comprising a positive electrode active material layer and a positive electrode current collector layer.

[0070] An insulating tape 1 was applied to the outer periphery of the surface of the obtained positive electrode on the side of the positive electrode active material layer, so that the area surrounded by the inner surface of the insulating tape was a rectangle of 30 mm × 40 mm. Next, Li6PS5Cl was added as a solid electrolyte to the area surrounded by the positive electrode active material layer and the insulating tape 1 so that the area was filled with the solid electrolyte, and then pressed with a roll press at a linear pressure of 2.0 ton / cm to obtain a laminate X consisting of a solid electrolyte layer, a positive electrode active material layer, and a positive electrode current collector layer.

[0071] A 50 μm-thick, 31 mm x 41 mm rectangular lithium foil was placed as the negative electrode active material on the solid electrolyte layer side of the obtained laminate X in a position that completely covered the portion of the surface surrounded by the inner surface of the insulating tape 1. A 10 μm-thick, 31 mm x 41 mm rectangular SUS foil was then placed on top of that as the negative electrode current collector. The resulting laminate was then pressed with a roll press at a linear pressure of 2.0 ton / cm to obtain a laminate Y consisting of 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. Here, the laminate Y has an area S of an overlap between the negative electrode active material layer side of the insulating member and at least one of the solid electrolyte layer and the negative electrode active material layer. A is 71mm 2 and the area S of the part surrounded by the inner surface of the insulating material B is 1200mm 2 Therefore, (S A / S B )×100 is 5.9%.

[0072] The obtained laminate Y was placed in an exterior body formed by processing a film mainly composed of aluminum, and a positive electrode tab and a negative electrode tab were connected to the positive electrode and the negative electrode, respectively, and the periphery of the exterior body was sealed to obtain an all-solid-state battery of Example 1. Here, one end of the positive electrode tab was connected to the positive electrode and the other end was extended to the outside of the exterior body, and one end of the negative electrode tab was connected to the negative electrode and the other end was extended to the outside of the exterior body. The all-solid-state battery of Example 1 is an all-solid-state battery of the embodiment shown in FIG.

[0073] (Examples 2 to 8, Comparative Examples 1 and 2) As shown in Table 1, all-solid-state batteries of Examples 2 to 8 and Comparative Examples 1 and 2 were obtained in the same manner as in Example 1, except that insulating tapes 2 to 10, each having a different surface arithmetic mean roughness Ra and maximum height roughness Rz, were used.

[0074] Examples 9 to 14 By changing the area of ​​the lithium foil and SUS foil, as shown in Table 2, (S A / S B All-solid-state batteries of Examples 9 to 14 were obtained in the same manner as in Example 4, except that the value (%) of (1)×100 was changed.

[0075] <Cell resistance> For the all-solid-state batteries of each Example and Comparative Example, the AC resistance (Ω) was measured at 1 kHz using an AC resistance meter (3560 AC milliohm high tester manufactured by Hioki E.E. Corporation), and this was taken as the cell resistance. The results are shown in Tables 1 and 2.

[0076] <Capacity maintenance rate> The all-solid-state batteries of each Example and Comparative Example were placed in a thermostatic chamber at 45°C and charged at 30 mA using a charge / discharge measurement system (HJ1005SD8, manufactured by Meiden Hokuto Co., Ltd.). After the upper limit voltage reached 4.2 V, they were charged at a constant voltage until the total charge time reached 2.5 hours. They were then discharged at a constant current of 30 mA until the lower limit voltage reached 2.5 V. This charge / discharge cycle was repeated 100 times, and the ratio (%) of the 100th discharge capacity to the first discharge capacity was defined as the capacity retention rate. The results are shown in Tables 1 and 2.

[0077] [Table 1]

[0078] [Table 2] [Explanation of symbols]

[0079] 10 Cathode active material layer 20 Solid electrolyte layer 30 Negative electrode active material layer 40 Insulating material 50 An overlapping portion between the surface of the insulating member on the negative electrode active material layer side and at least one of the solid electrolyte layer and the negative electrode active material layer

Claims

1. a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order; the positive electrode active material layer further includes an insulating member in contact with an outer surface of the positive electrode active material layer or an outer periphery of a surface of the positive electrode active material layer on the side of the solid electrolyte layer, an arithmetic mean roughness Ra of the surface of the insulating member facing the negative electrode active material layer, measured in accordance with JIS B0601:2013, of 0.10 μm or more and 10.0 μm or less.

2. The area of ​​the overlapping portion between the surface of the insulating member on the negative electrode active material layer side and at least one of the solid electrolyte layer and the negative electrode active material layer is defined as S Ａ The area of ​​the part surrounded by the inner surface of the insulating member is S Ｂ When this is done, (S Ａ / S Ｂ 2. The all-solid-state battery according to claim 1, wherein the value of (%) × 100(%) is 0.1% or more and 50.0% or less.

3. 3. The all-solid-state battery according to claim 1, wherein a surface of the insulating member facing the negative electrode active material layer has a maximum height roughness Rz of 0.50 μm or more and 20.0 μm or less, as measured in accordance with JIS B0601:2013.

4. the insulating member is in contact with the outer surface of the positive electrode active material layer, The all-solid-state battery according to any one of claims 1 to 3, wherein the insulating member has a thickness smaller than that of the positive electrode active material layer.

5. the insulating member is in contact with the outer surface of the positive electrode active material layer, 4. The all-solid-state battery according to claim 1, wherein the thickness of the insulating member is equal to or greater than the thickness of the positive electrode active material layer and is equal to or less than the sum of the thickness of the positive electrode active material layer and the thickness of the solid electrolyte layer.

6. the insulating member is in contact with the outer surface of the positive electrode active material layer, 4. The all-solid-state battery according to claim 1, wherein the thickness of the insulating member is greater than the sum of the thickness of the positive electrode active material layer and the thickness of the solid electrolyte layer.

7. the insulating member contacts an outer periphery of a surface of the positive electrode active material layer facing the solid electrolyte layer, 4. The all-solid-state battery according to claim 1, wherein the insulating member has a thickness smaller than that of the solid electrolyte layer.

8. the insulating member contacts an outer periphery of a surface of the positive electrode active material layer facing the solid electrolyte layer, 4. The all-solid-state battery according to claim 1, wherein the insulating member has a thickness equal to or greater than the thickness of the solid electrolyte layer.

9. The all-solid-state battery according to any one of claims 1 to 8, wherein the negative electrode active material layer contains one or more negative electrode active materials selected from the group consisting of carbon materials, lithium-based metal materials, Si-based materials, and conductive polymer materials.

10. 10. The all-solid-state battery according to claim 1, wherein the solid electrolyte layer comprises one or more solid electrolyte materials selected from the group consisting of an oxide-based solid electrolyte material, a sulfide-based solid electrolyte material, a polymer-based solid electrolyte material, and a halogen-based solid electrolyte material.

11. The all-solid-state battery according to any one of claims 1 to 10, wherein the insulating member comprises one or more materials selected from the group consisting of a resin-based insulating material, a glass fiber-based insulating material, a butyl rubber-based insulating material, and a material containing an insulating metal oxide.

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