All-solid battery

Abstract

To provide an all-solid battery that can ensure insulation even when the spatial distance between a tab wire and a positive electrode current collector is shortened due to bending of the tab wire when the tab wires extending from the negative electrode current collector of the respective cell structure are assembled to function as a battery.SOLUTION: In an all-solid battery including an electrode body in which a positive electrode current collector, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode current collector are stacked in this order, a first insulating material is provided at an end of the positive electrode layer, and a second insulating material is provided between the negative electrode current collector and the solid electrolyte layer in a portion facing the end of the solid electrolyte layer and the end of the first insulating material.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] In recent years, research and development has been conducted on secondary batteries that contribute to energy efficiency in order to ensure that more people have access to affordable, reliable, sustainable, and advanced energy. As a secondary battery, lithium metal batteries, which have high energy density, have attracted attention.

[0003] Lithium metal batteries are secondary batteries that use lithium metal as the negative electrode, and can be high-capacity batteries. Among them, so-called all-solid-state lithium metal batteries, which are all-solidified by replacing the electrolyte with a solid electrolyte layer, have attracted attention for their excellent safety. The all-solid-state lithium metal battery has a cell structure that includes, for example, a negative electrode made of lithium metal, a positive electrode, and a solid electrolyte layer.

[0004] FIG. 5 is a cross-sectional view showing the configuration of a conventional all-solid-state battery. The all-solid-state battery 1 shown in FIG. 5 includes a negative electrode formed of a negative electrode collector 2a and a lithium metal layer (negative electrode layer) 3a, or a negative electrode collector 2b and a lithium metal layer (negative electrode layer) 3b, a positive electrode formed of a positive electrode collector 4 and a positive electrode active material layer (positive electrode layer) 5a or 5b, and solid electrolyte layers 6a and 6b adjacent to the positive electrode active material layer (positive electrode layer) 5a or 5b. The all-solid-state battery 1 shown in FIG. 5 includes an intermediate layer 7a between the lithium metal layer (negative electrode layer) 3a and the solid electrolyte layer 6a, and an intermediate layer 7b between the lithium metal layer (negative electrode layer) 3b and the solid electrolyte layer 6b. In addition, first insulating materials 8a and 8c are respectively arranged at both ends of the positive electrode active material layer (positive electrode layer) 5a, and first insulating materials 8b and 8d are respectively arranged at both ends of the positive electrode active material layer 5b. In addition, L in the figure indicates the lamination direction of the layers constituting the all-solid-state battery 1.

[0005] An all-solid-state battery includes an electrode body in which a plurality of such cell structures are stacked, and the tab wires extending from the negative electrode current collectors of each cell structure are assembled to function as a battery. When the tab wires are assembled, the tab wires extending from the electrode body are bent, and the bending of the tab wires located far from the assembly part is particularly large. As a result, there was a concern that the spatial distance between the tab wires and the positive electrode current collector would be shortened, making it impossible to ensure an insulating distance.

[0006] Patent Document 1 discloses an all-solid-state battery in which, in an electrode body in which a positive electrode current collector foil, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode current collector foil are laminated in this order, the positive electrode layer is laminated and positioned more inward than the solid electrolyte layer and the negative electrode layer, and an insulating layer is disposed on the surface of the positive electrode current collector foil facing the positive electrode layer, at least in portions that face the ends of the solid electrolyte layer and the negative electrode layer.

[0007] The insulating layer applied to the all-solid-state battery described in Patent Document 1 is a ceramic layer adhered to the positive electrode current collector foil via an adhesive layer, and the ceramic layer has high hardness and is expected to suppress damage to the insulating layer due to metallic foreign matter and to suppress short circuits, and even if a short circuit does occur, the high resistance of the ceramic layer is expected to have the effect of suppressing heat generation at the short-circuited area.

[0008] However, since the insulating layer described in Patent Document 1 has a ceramic layer, it is not envisaged that the insulating layer itself will be used in a bent state. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2022-104116 A Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention aims to provide an all-solid-state battery that can ensure insulation even when the spatial distance between the tab wire and the positive electrode current collector is shortened due to bending of the tab wire when tab wires extending from negative electrode current collectors of respective cell structures are assembled to function as a battery. [Means for solving the problem]

[0011] The present inventors have conducted intensive research to achieve the above object. In an all-solid-state battery including an electrode assembly in which a positive electrode collector, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode collector are stacked in this order, the inventors have found that insulation can be ensured by the creepage distance by providing a first insulating material at an end of the positive electrode layer and a second insulating material between the negative electrode collector and the solid electrolyte layer and in a portion facing the end of the solid electrolyte layer and the end of the first insulating material so that the creepage distance from the surface of the negative electrode collector on the negative electrode layer side to the surface of the positive electrode collector on the positive electrode layer side is greater than the linear distance, and have completed the present invention.

[0012] That is, the present invention includes the following aspects. [1] An all-solid-state battery including an electrode assembly in which a positive electrode current collector, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode current collector are laminated in this order, the positive electrode current collector includes a first insulating material on a surface on the positive electrode layer side, the first insulating material being adjacent to an end of the positive electrode layer; the solid electrolyte layer is disposed in contact with the positive electrode layer and the first insulating material; a second insulating material is provided between the negative electrode current collector and the solid electrolyte layer and in a portion facing an end of the solid electrolyte layer and an end of the first insulating material; the second insulating material is disposed in contact with the solid electrolyte layer such that a creepage distance from a surface of the negative electrode current collector on the negative electrode layer side to a surface of the positive electrode current collector on the positive electrode layer side is greater than the linear distance. All-solid-state battery. [2] The all-solid-state battery according to aspect [1], wherein the first insulating material has a thickness in a stacking direction of the electrode body that decreases as the distance from the end adjacent to the positive electrode layer increases in the extension direction of the electrode body. [3] The all-solid-state battery according to aspect [1] or [2], wherein the second insulating material is arranged so as to overlap an end of the negative electrode layer in an extension direction of the electrode body. [4] The all-solid-state battery according to aspect [3], wherein at least a portion of the second insulating material is disposed in contact with the negative electrode current collector. [5] the electrode body includes an intermediate layer between the solid electrolyte layer and the negative electrode layer, The all-solid-state battery according to aspect [1] or [2], wherein, in an extension direction of the electrode body, an end of the intermediate layer is disposed at substantially the same position as an end of the negative electrode layer or an end of the second insulating material, or is disposed more inward than the end of the negative electrode layer or the end of the second insulating material. [6] The all-solid-state battery according to aspect [5], wherein at least a portion of the second insulating material is disposed in contact with the intermediate layer. [7] The all-solid-state battery according to aspect [1] or [2], wherein an end of the solid electrolyte layer is located at substantially the same position as an end of the first insulating material in an extension direction of the electrode body. [8] the second insulating material is a laminate including an adhesive layer and an insulating layer; the adhesive layer is disposed on the negative electrode current collector side, The all-solid-state battery according to aspect [1] or [2], wherein the insulating layer is disposed on the solid electrolyte layer side. [9] The adhesive layer is an acrylic adhesive layer, The all-solid-state battery of embodiment [8], wherein the insulating layer comprises polyethylene. Effect of the Invention

[0013] According to the present invention, it is possible to provide an all-solid-state battery capable of ensuring insulation. [Brief description of the drawings]

[0014] [Figure 1] 1 is a partial cross-sectional view showing the configuration of an all-solid-state battery according to a first embodiment. [Diagram 2] FIG. 6 is a partial cross-sectional view showing the configuration of an all-solid-state battery according to a second embodiment. [Diagram 3] FIG. 11 is a partial cross-sectional view showing the configuration of an all-solid-state battery according to a third embodiment. [Figure 4] FIG. 11 is a partial cross-sectional view showing the configuration of an all-solid-state battery according to a fourth embodiment. [Diagram 5] FIG. 1 is a cross-sectional view showing the configuration of a conventional all-solid-state battery. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment will be described with reference to the drawings. First Embodiment The all-solid-state battery of the present disclosure will be described with reference to an all-solid-state battery 11 as one embodiment.

[0016] The all-solid-state battery of the present disclosure includes an electrode assembly in which a positive electrode current collector, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode current collector are laminated in this order. The positive electrode current collector includes a first insulating material on a surface facing the positive electrode layer and adjacent to an end of the positive electrode layer, and the solid electrolyte layer is disposed in contact with the positive electrode layer and the first insulating material.

[0017] The all-solid-state battery of the present disclosure further includes a second insulating material between the negative electrode current collector and the solid electrolyte layer, the second insulating material being disposed in contact with the solid electrolyte layer such that the creepage distance from the surface of the negative electrode current collector facing the negative electrode layer to the surface of the positive electrode current collector facing the positive electrode layer is greater than the linear distance.

[0018] The all-solid-state battery of the present disclosure includes a first insulating material at an end of the positive electrode layer, and a second insulating material between the negative electrode current collector and the solid electrolyte layer, which is located opposite the end of the solid electrolyte layer and the end of the first insulating material, such that the creepage distance from the surface of the negative electrode current collector on the negative electrode layer side to the surface of the positive electrode current collector on the positive electrode layer side is greater than the linear distance. Therefore, insulation can be ensured by the creepage distance.

[0019] More specifically, when the tab wires extending from the negative electrode current collectors of the respective cell structures are assembled to function as a battery, even if the spatial distance between the tab wire and the positive electrode current collector is shortened due to bending of the tab wire, the creepage distance can be secured, so that insulation can be guaranteed.

[0020] Fig. 1 is a part of a cross-sectional view showing the configuration of an all-solid-state battery 11 according to the first embodiment. Fig. 1 shows an end of a cell structure of the all-solid-state battery 11. The all-solid-state battery 11 shown in Fig. 1 includes a positive electrode formed of a positive electrode current collector 140 and a positive electrode active material layer (positive electrode layer) 15a or 15b, solid electrolyte layers 16a and 16b adjacent to the positive electrode active material layer (positive electrode layer) 15a or 15b, and a negative electrode formed of a lithium metal layer (negative electrode layer) 13a and a negative electrode current collector 12a, or a lithium metal layer (negative electrode layer) 13b and a negative electrode current collector 12b.

[0021] 1 includes an intermediate layer 17a between the lithium metal layer (negative electrode layer) 13a and the solid electrolyte layer 16a, and an intermediate layer 17b between the lithium metal layer (negative electrode layer) 13b and the solid electrolyte layer 16b. A first insulating material 18c is disposed at an end of the positive electrode active material layer (positive electrode layer) 15a, and a first insulating material 18d is disposed at an end of the positive electrode active material layer (positive electrode layer) 15b.

[0022] In the all-solid-state battery 11 according to the first embodiment shown in FIG. 1, the intermediate layers 17a and 17b have their ends disposed inward in the extension direction of the electrode body relative to the ends of the lithium metal layers (negative electrode layers) 13a and 13b, respectively.

[0023] The all-solid-state battery 11 shown in FIG. 1 includes first insulating materials 18c and 18d at the ends of the positive electrode layers 15a and 15b, respectively, and also includes a second insulating material 19a between the negative electrode current collector 12a and the solid electrolyte layer 16a, in a portion facing the end of the solid electrolyte layer 16a and the end of the first insulating material 18c, such that the creepage distance from the surface of the negative electrode current collector 12a on the negative electrode layer 13a side to the surface of the positive electrode current collector 140 on the positive electrode layer 15a side is larger than the straight-line distance (indicated by the arrow b in the figure).

[0024] More specifically, the second insulating material 19a of the all-solid-state battery 11 according to the first embodiment is disposed so that a part of its surface overlaps with the end of the negative electrode layer 13a in the extending direction of the electrode body of the all-solid-state battery 11, and the overlapping part covers the negative electrode layer 13a, and the second insulating material 19a is disposed in contact with the negative electrode current collector 12a without contacting the end of the intermediate layer 17a. The other surface of the second insulating material 19a is in contact with the solid electrolyte layer 16a, except for the part indicated by the arrow a in FIG. 1.

[0025] That is, in the all-solid-state battery 11 shown in FIG. 1, one surface of the second insulating material 19a is in partial contact with the negative electrode layer 13a and the remainder is in contact with the negative electrode current collector 12a in the extending direction of the electrode body, and the surface opposite to the surface in contact with the negative electrode layer 13a and the negative electrode current collector 12a is disposed so as to partially abut against the solid electrolyte layer 16a with the portion indicated by arrow a in FIG. 1 protruding from the end of the solid electrolyte layer 16a.

[0026] As a result, in the all-solid-state battery 11, even if the spatial distance between the tab wire and the positive electrode current collector 140 is shortened due to bending of the tab wire when the tab wire is assembled to function as a battery, the creepage distance between the surface of the negative electrode current collector 12a on the negative electrode layer 13a side to the surface of the positive electrode current collector 140 on the positive electrode layer 15a side is increased because it follows the surface of the second insulating material 19a due to the presence of the second insulating material 19a at the portion of the arrow a protruding from the end of the solid electrolyte layer 16a. As a result, the all-solid-state battery 11 can ensure the creepage distance and ensure insulation.

[0027] In addition, since the second insulating material 19a has a portion indicated by arrow a that protrudes from the end of the solid electrolyte layer 16a, when the tab wires extending from the negative electrode current collector 12a are assembled to function as a battery, even if the tab wires are bent and stress is concentrated at the bent portion, the presence of the second insulating material 19a improves the mechanical strength, and therefore breakage of the tab wires, etc. can be suppressed.

[0028] In the all-solid-state battery of the present disclosure, the distance by which the second insulating material protrudes from the solid electrolyte it abuts (arrow a in FIG. 1) is not particularly limited. As long as the end of the second insulating material is positioned outside the end of the solid electrolyte in the extending direction of the electrode body, the above-mentioned effects of the present invention can be obtained.

[0029] <Second embodiment> A part of a cross-sectional view showing the configuration of an all-solid-state battery 12 according to a second embodiment is shown in Fig. 2. Fig. 2 shows an end of a cell structure of the all-solid-state battery 12. The all-solid-state battery 12 shown in Fig. 2 includes a positive electrode formed of a positive electrode current collector 24 and a positive electrode active material layer (positive electrode layer) 25a or 25b, solid electrolyte layers 26a and 26b adjacent to the positive electrode active material layer (positive electrode layer) 25a or 25b, and a negative electrode formed of a lithium metal layer (negative electrode layer) 23a and a negative electrode current collector 22a, or a lithium metal layer (negative electrode layer) 23b and a negative electrode current collector 22b.

[0030] 2 includes an intermediate layer 27a between the lithium metal layer (negative electrode layer) 23a and the solid electrolyte layer 26a, and an intermediate layer 27b between the lithium metal layer (negative electrode layer) 23b and the solid electrolyte layer 26b. A first insulating material 28c is disposed at an end of the positive electrode active material layer (positive electrode layer) 25a, and a first insulating material 28d is disposed at an end of the positive electrode active material layer (positive electrode layer) 25b.

[0031] In the all-solid-state battery 12 according to the second embodiment shown in FIG. 2, the intermediate layers 27a and 27b have ends arranged at approximately the same positions as the ends of the lithium metal layers (negative electrode layers) 23a and 23b, respectively, in the extension direction of the electrode body.

[0032] The all-solid-state battery 12 shown in FIG. 2 includes first insulating materials 28c and 28d at the ends of the positive electrode layers 25a and 25b, respectively, and includes a second insulating material 29a between the negative electrode current collector 22a and the solid electrolyte layer 26a, in a portion facing the end of the solid electrolyte layer 26a and the end of the first insulating material 28c, such that the creepage distance from the surface of the negative electrode current collector 22a on the negative electrode layer 23a side to the surface of the positive electrode current collector 24 on the positive electrode layer 25a side is larger than the linear distance.

[0033] More specifically, the second insulating material 29a of the all-solid-state battery 12 according to the second embodiment is disposed in contact with the negative electrode current collector 22a without overlapping with the negative electrode layer 23a and the intermediate layer 27a in the extending direction of the electrode body of the all-solid-state battery 12. The other surface of the second insulating material 29a is in contact with the solid electrolyte layer 26a.

[0034] That is, in the all-solid-state battery 12 shown in FIG. 2, one surface of the second insulating material 29a is in full contact with the negative electrode current collector 22a in the extending direction of the electrode body, and the surface opposite to the surface in contact with the negative electrode current collector 22a is disposed so as to partly abut against the solid electrolyte layer 26a while protruding from the end of the solid electrolyte layer 26a.

[0035] As a result, in the all-solid-state battery 12, as in the above-described embodiment, for example, when the tab wires extending from the negative electrode current collector 22 a are assembled to function as a battery, even if the tab wires are bent, the creepage distance can be secured to ensure insulation, and breakage of the tab wires can be suppressed by improving the mechanical strength.

[0036] <Third embodiment> A part of a cross-sectional view showing the configuration of an all-solid-state battery 13 according to a third embodiment is shown in Fig. 3. Fig. 3 shows an end of a cell structure of the all-solid-state battery 13. The all-solid-state battery 13 shown in Fig. 3 includes a positive electrode formed of a positive electrode current collector 34 and a positive electrode active material layer (positive electrode layer) 35a or 35b, solid electrolyte layers 36a and 36b adjacent to the positive electrode active material layer (positive electrode layer) 35a or 35b, and a negative electrode formed of a lithium metal layer (negative electrode layer) 33a and a negative electrode current collector 32a, or a lithium metal layer (negative electrode layer) 33b and a negative electrode current collector 32b.

[0037] 3 includes an intermediate layer 37a between the lithium metal layer (negative electrode layer) 33a and the solid electrolyte layer 36a, and an intermediate layer 37b between the lithium metal layer (negative electrode layer) 33b and the solid electrolyte layer 36b. A first insulating material 38c is disposed at an end of the positive electrode active material layer (positive electrode layer) 35a, and a first insulating material 38d is disposed at an end of the positive electrode active material layer (positive electrode layer) 35b.

[0038] In the all-solid-state battery 13 according to the third embodiment shown in FIG. 3, the intermediate layers 37a and 37b have ends arranged at approximately the same positions as the ends of the lithium metal layers (negative electrode layers) 33a and 33b, respectively, in the extension direction of the electrode body.

[0039] The all-solid-state battery 13 shown in FIG. 3 includes first insulating materials 38c and 38d at the ends of the positive electrode layers 35a and 35b, respectively, and includes a second insulating material 39a between the negative electrode current collector 32a and the solid electrolyte layer 36a, in a portion facing the end of the solid electrolyte layer 36a and the end of the first insulating material 38c, such that the creepage distance from the surface of the negative electrode current collector 32a on the negative electrode layer 33a side to the surface of the positive electrode current collector 34 on the positive electrode layer 35a side is larger than the linear distance.

[0040] More specifically, the second insulating material 39a of the all-solid-state battery 13 according to the third embodiment is disposed in contact with the negative electrode current collector 32a without overlapping with the negative electrode layer 33a and the intermediate layer 37a in the extending direction of the electrode body of the all-solid-state battery 13. The other surface of the second insulating material 39a is in contact with the solid electrolyte layer 36a.

[0041] That is, in the all-solid-state battery 13 shown in FIG. 3, one surface of the second insulating material 39a is in full contact with the intermediate layer 37a in the extending direction of the electrode body, and the surface opposite to the surface in contact with the intermediate layer 37a is disposed so as to partially abut against the solid electrolyte layer 36a while protruding from the end of the solid electrolyte layer 36a.

[0042] Thereby, in the all-solid-state battery 13, similarly to the above-described embodiment, for example, when the tab wires extending from the negative electrode current collector 32a are assembled to function as a battery, even if the tab wires are bent, the creepage distance can be secured and insulation can be guaranteed, and breakage of the tab wires can be suppressed by improving the mechanical strength.

[0043] <Fourth embodiment> A part of a cross-sectional view showing the configuration of an all-solid-state battery 14 according to a fourth embodiment is shown in Fig. 4. Fig. 4 shows an end of a cell structure of the all-solid-state battery 14. The all-solid-state battery 14 shown in Fig. 4 includes a positive electrode formed of a positive electrode current collector 44 and a positive electrode active material layer (positive electrode layer) 45a or 45b, solid electrolyte layers 46a and 46b adjacent to the positive electrode active material layer (positive electrode layer) 45a or 45b, and a negative electrode formed of a lithium metal layer (negative electrode layer) 43a and a negative electrode current collector 42a, or a lithium metal layer (negative electrode layer) 43b and a negative electrode current collector 42b.

[0044] 4 includes an intermediate layer 47a between a lithium metal layer (negative electrode layer) 43a and a solid electrolyte layer 46a, and an intermediate layer 47b between a lithium metal layer (negative electrode layer) 43b and a solid electrolyte layer 46b. A first insulating material 48c is disposed at an end of the positive electrode active material layer (positive electrode layer) 45a.

[0045] In the all-solid-state battery 14 according to the first embodiment shown in FIG. 4, an end of the intermediate layer 47a is disposed more inward than an end of the lithium metal layer (negative electrode layer) 43a in the extending direction of the electrode body.

[0046] In the all-solid-state battery 14 according to the fourth embodiment, the first insulating material 48c has a thickness in the stacking direction of the electrode body (arrow L in FIG. 4) that decreases as the distance (arrow c in FIG. 4) from the end adjacent to the positive electrode active material layer (positive electrode layer) 45a increases in the extending direction of the electrode body. That is, the first insulating material 48c has a shape that is inclined in the stacking direction of the electrode body (arrow L in FIG. 4), and the inclined portion forms a gap.

[0047] The all-solid-state battery 14 shown in FIG. 4 includes a first insulating material 48c at an end of the positive electrode layer 45a, and includes a second insulating material 49a between the negative electrode current collector 42a and the solid electrolyte layer 46a, in a portion facing the end of the solid electrolyte layer 46a and the end of the first insulating material 48c, such that the creepage distance from the surface of the negative electrode current collector 42a on the negative electrode layer 43a side to the surface of the positive electrode current collector 44 on the positive electrode layer 45a side is larger than the linear distance.

[0048] More specifically, in the second insulating material 49a of the all-solid-state battery 14 according to the fourth embodiment, in the same manner as in the first embodiment, in the extending direction of the electrode body of the all-solid-state battery 14, one surface is in partial contact with the negative electrode layer 43a and the remainder is in contact with the negative electrode current collector 42a, and the surface opposite to the surface in contact with the negative electrode layer 43a and the negative electrode current collector 42a is disposed so as to partially abut against the solid electrolyte layer 16a in a state protruding from the end of the solid electrolyte layer 46a.

[0049] That is, in the all-solid-state battery 14 shown in FIG. 4, one surface of the second insulating material 49a is in partial contact with the negative electrode layer 43a and the remainder is in contact with the negative electrode current collector 42a in the extending direction of the electrode body, and the surface opposite to the surface in contact with the negative electrode layer 43a and the negative electrode current collector 42a is disposed so as to partially abut against the solid electrolyte layer 46a in a state where it protrudes from the end of the solid electrolyte layer 46a.

[0050] 4, the second insulating material 49a is a laminate including an adhesive layer 491 and an insulating layer 492. The adhesive layer 491 is disposed so as to abut against the negative electrode current collector 42a, and the insulating layer 492 is disposed so as to abut against the solid electrolyte layer 46a.

[0051] Thereby, in the all-solid-state battery 14, as in the above-described embodiment, for example, when the tab wires extending from the negative electrode current collector 42a are assembled to function as a battery, even if the tab wires are bent, the creepage distance can be secured and insulation can be guaranteed, and breakage of the tab wires can be suppressed by improving the mechanical strength.

[0052] In particular, in the all-solid-state battery 14 according to the fourth embodiment, the first insulating material 48c has a shape that is inclined in the stacking direction of the electrode body (arrow L in FIG. 4), and a gap is formed in the inclined portion. Then, the second insulating material 49a is disposed in the gap region, so that it is possible to suppress the generation of pressure due to the presence of the second insulating material 49a when pressing or laminating the electrode body.

[0053] Hereinafter, each component of the all-solid-state battery according to the present disclosure will be described.

[0054] [Positive electrode] The positive electrode of the all-solid-state battery of the present disclosure includes a positive electrode current collector and a positive electrode layer. In the all-solid-state battery of the present disclosure, the positive electrode layer abuts against the positive electrode current collector. (Positive electrode current collector) The positive electrode current collector used in the all-solid-state battery of the present disclosure is disposed in contact with the positive electrode layer and has a function of collecting the current from the positive electrode layer. The material of the positive electrode current collector is not particularly limited as long as it can collect the current from the positive electrode layer. Examples of the material of the positive electrode current collector include aluminum, aluminum alloy, stainless steel, nickel, iron, and titanium, and among them, at least one selected from the group consisting of aluminum, aluminum alloy, and stainless steel is preferable.

[0055] The shape of the positive electrode current collector is not particularly limited, and may be, for example, a foil or a plate. The thickness of the positive electrode current collector is not particularly limited, and may be the same as that used in the positive electrode of a general all-solid-state battery. The thickness of the positive electrode current collector may be, for example, in the range of 0.1 μm to 1 mm.

[0056] (Positive electrode layer) The positive electrode layer is a layer containing at least a positive electrode active material. The positive electrode active material contained in the positive electrode layer is not particularly limited as long as it is used in the positive electrode layer of a general all-solid-state battery. For example, in the case of a lithium ion battery, examples of the positive electrode active material include a layered active material containing lithium, a spinel type active material, and an olivine type active material. Specific examples of the positive electrode active material include lithium cobalt oxide (LiCoO 2 ), lithium nickel oxide (LiNiO 2 ), LiNi p Mn q Co r O 2 (p+q+r=1), LiNi p Al q Co r O 2 (p+q+r=1), lithium manganate (LiMn 2 O 4 ), Li 1 +xMn 2 -x-yMyO 4 Li-Mn spinel substituted with different elements represented by the formula (x+y=2, M=at least one selected from Al, Mg, Co, Fe, Ni, and Zn), lithium titanate (oxide containing Li and Ti), lithium metal phosphate (LiMPO 4 , M=at least one selected from Fe, Mn, Co, and Ni).

[0057] The content of the positive electrode active material in the positive electrode layer may be, for example, in the range of 50% by mass to 99% by mass. 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.

[0058] The positive electrode layer may optionally contain a solid electrolyte, which will be described later, for the purpose of improving lithium ion conductivity. The positive electrode layer may also optionally contain a binder, a conductive assistant, etc. As these substances, those generally used in all-solid-state batteries can be used.

[0059] The thickness of the positive electrode layer is not particularly limited and can be appropriately set depending on the desired performance of the battery. The thickness of the positive electrode layer may be, for example, in the range of 0.1 μm to 1 mm.

[0060] When the all-solid-state battery of the present disclosure includes an intermediate layer described later, the positive electrode layer preferably has an area equivalent to that of the intermediate layer on the lamination surface. This can improve the energy density of the all-solid-state battery. The area of ​​the positive electrode layer in the all-solid-state battery of the present disclosure may be, for example, up to 100% of the area of ​​the intermediate layer, or may be 90% to 100%, or may be 80% to 90%.

[0061] The method for producing the positive electrode layer is not particularly limited, and the positive electrode layer can be produced by a known method. For example, the positive electrode layer can be produced by mixing the materials constituting the positive electrode layer with a solvent to form a slurry, applying the slurry to the positive electrode current collector described above, and drying the slurry.

[0062] [Solid electrolyte layer] The solid electrolyte layer is a layer including a solid electrolyte and is disposed in contact with the positive electrode layer and the first insulating material.

[0063] The material of the solid electrolyte is not particularly limited as long as it has lithium ion conductivity and insulating properties. As the material of the solid electrolyte, materials generally used in all-solid-state lithium ion batteries can be used, and examples thereof include sulfide solid electrolyte materials, oxide solid electrolyte materials, halide solid electrolytes, inorganic solid electrolytes such as lithium-containing salts, polymer-based solid electrolytes such as polyethylene oxide, and gel-based solid electrolytes containing lithium-containing salts and lithium ion conductive ionic liquids. Among these, sulfide solid electrolyte materials are preferred from the viewpoint of high lithium ion conductivity and good structural formability and interface bonding properties by pressing.

[0064] The form of the solid electrolyte material is not particularly limited, and may be, for example, particulate. In the solid electrolyte layer of the all-solid-state battery of the present disclosure, the content of the solid electrolyte is not particularly limited. The content of the solid electrolyte may be, for example, in the range of 50% by mass to 99% by mass.

[0065] The solid electrolyte layer may optionally contain a binder. In addition, for the purpose of imparting mechanical strength and flexibility, it may optionally contain an adhesive. As these materials, those generally used in all-solid-state batteries can be used.

[0066] The solid electrolyte layer may be disposed such that an end portion is substantially in the same position as an end portion of the first insulating material in the extending direction of the electrode body of the all-solid-state battery of the present disclosure.

[0067] In an electrode body having such a shape, the solid electrolyte layer does not protrude from the end face of the electrode body, and therefore, for example, when pressure is applied by a roll press or the like during the manufacturing process of the electrode body, the occurrence of cracks in the solid electrolyte layer can be suppressed.

[0068] The method for producing the solid electrolyte layer is not particularly limited, and the solid electrolyte layer can be produced by a known method. For example, the solid electrolyte layer can be produced by mixing the materials constituting the solid electrolyte layer with a solvent to form a slurry, applying the slurry to a substrate, and drying the slurry.

[0069] [Negative electrode] The negative electrode of the all-solid-state battery of the present disclosure includes a negative electrode current collector and a negative electrode layer. In the all-solid-state battery of the present disclosure, the negative electrode layer is in contact with the negative electrode current collector.

[0070] (Negative electrode current collector) The negative electrode current collector used in the all-solid-state battery of the present disclosure is disposed in contact with the negative electrode layer and has a function of collecting current from the negative electrode layer. The material of the negative electrode current collector is not particularly limited as long as it can collect current from the negative electrode layer, but it is preferable that the negative electrode current collector is made of a substance with high electrical conductivity. Examples of substances with high electrical conductivity include metals containing at least one metal element selected from the group consisting of silver, palladium, gold (Pt), platinum, aluminum, copper, and nickel, alloys such as stainless steel, and non-metals such as carbon (C).

[0071] Among these highly conductive materials, in consideration of the manufacturing cost as well as the high conductivity, it is preferable to use at least one selected from the group consisting of copper, SUS, and nickel. In particular, since stainless steel material is difficult to react with the negative electrode active material, the positive electrode active material, and the solid electrolyte, the internal resistance of the all-solid-state battery can be reduced by using the stainless steel material as the material of the negative electrode current collector.

[0072] The shape of the negative electrode current collector is not particularly limited, and examples thereof include a foil, a plate, a mesh, a nonwoven fabric, a foam, etc. Furthermore, the negative electrode current collector may have a carbon layer or the like disposed on the surface thereof, or the surface may be roughened, in order to enhance adhesion with the negative electrode layer.

[0073] The thickness of the negative electrode current collector is not particularly limited and may be the same as that used in the negative electrode of a general all-solid-state battery. The thickness of the negative electrode current collector may be, for example, in the range of 0.1 μm to 1 mm.

[0074] (Negative electrode layer) The negative electrode layer is a layer containing a negative electrode active material that gives and receives lithium ions and electrons. The negative electrode active material contained in the negative electrode layer is not particularly limited as long as it is used in the negative electrode layer of a general all-solid-state battery, but it is preferable to use a material with high electronic conductivity that can reversibly release and absorb lithium ions and easily transport electrons. Examples of such negative electrode active materials include silicon-based active materials such as silicon and silicon alloys, carbon-based active materials such as graphite and hard carbon, various oxide-based active materials such as lithium titanate, lithium-metal and lithium-based active materials such as lithium alloys. The negative electrode active material may be one of the above materials alone or two or more of them may be used in combination.

[0075] In the all-solid-state battery of the present disclosure, the negative electrode layer may be made of metallic lithium or a lithium metal alloy, or a mixture of lithium metal or a lithium metal alloy. A negative electrode layer made of lithium metal or a lithium metal alloy, or a mixture of lithium metal or a lithium metal alloy, has a large electric capacity per unit weight, and therefore a high-capacity all-solid-state battery can be realized.

[0076] The content of the negative electrode active material in the negative electrode layer may be in the range of, for example, 30% by mass to 100% by mass.

[0077] The negative electrode layer may optionally contain the above-mentioned solid electrolyte for the purpose of improving lithium ion conductivity. The negative electrode layer may also optionally contain a binder, a conductive assistant, etc. As these substances, those generally used in all-solid-state batteries can be used.

[0078] The thickness of the negative electrode layer is not particularly limited and can be appropriately set depending on the desired performance of the battery. The thickness of the negative electrode layer may be, for example, in the range of 0.1 μm to 1 mm.

[0079] The method for producing the negative electrode layer is not particularly limited, and the negative electrode layer can be produced by a known method. For example, the negative electrode layer can be produced by mixing the materials constituting the negative electrode layer with a solvent to form a slurry, applying the slurry to the negative electrode current collector described above, and drying the slurry.

[0080] [Middle layer] When the all-solid-state battery of the present disclosure includes an intermediate layer, the intermediate layer is provided between the solid electrolyte and the negative electrode layer. When the negative electrode layer of the all-solid-state battery of the present disclosure is a layer of metallic lithium or a lithium metal alloy alone or in combination, providing the intermediate layer between the solid electrolyte layer and the negative electrode layer can suppress non-uniform deposition of dendrites at the interface between the solid electrolyte layer and the negative electrode layer and can improve the interface adhesion.

[0081] The intermediate layer is a layer having electronic conductivity and ionic conductivity. Since the intermediate layer has ionic conductivity, it can pass, for example, lithium ions. Therefore, as the all-solid-state battery is repeatedly charged and discharged, lithium ions (Li + ) passes through the intermediate layer. The presence of the intermediate layer allows lithium metal to be uniformly deposited between the intermediate layer and the negative electrode layer. In addition, when the intermediate layer has flexibility that allows it to follow the volumetric changes of each layer accompanying charge and discharge, it is possible to maintain the interfacial adhesion even when the all-solid-state battery is repeatedly charged and discharged, and thus the durability of the all-solid-state battery can be improved.

[0082] The intermediate layer may be disposed such that an end portion thereof is substantially co-located with an end portion of the negative electrode layer or an end portion of the second insulating material in the extending direction of the electrode body of the all-solid-state battery of the present disclosure, or may be disposed inside the end portion of the negative electrode layer or the end portion of the second insulating material, thereby allowing the above-mentioned effect of disposing the intermediate layer to be fully exerted.

[0083] The material constituting the intermediate layer is not particularly limited, but may contain, for example, amorphous carbon, metal nanoparticles, and a binder as a binding material.

[0084] Unlike graphite, for example, amorphous carbon does not react with lithium metal to form an alloy, and therefore can suppress the formation of dendrites and improve the cycle characteristics of the all-solid-state battery.

[0085] Examples of amorphous carbon include carbon blacks such as acetylene black, furnace black, and ketjen black, coke, activated carbon, etc. The amorphous carbon may be easily graphitized carbon (soft carbon), or may be hardly graphitized carbon (hard carbon), CNT (carbon nanotube), fullerene, or graphene.

[0086] The metal nanoparticles contained in the intermediate layer can increase the electronic conductivity of the intermediate layer, and as a result, lithium metal can be more uniformly precipitated. The metal nanoparticles are not particularly limited, but examples thereof include metal nanoparticles of tin, silicon, zinc, magnesium, gold, platinum, palladium, silver, aluminum, bismuth, antimony, etc.

[0087] The binder contained in the intermediate layer maintains the structure of the intermediate layer and improves the adhesion between the particles constituting the intermediate layer and between the intermediate layer and the solid electrolyte layer. The binder is not particularly limited, and any binder generally used in all-solid-state batteries can be used.

[0088] [First insulating material] The first insulating material is provided on the surface of the positive electrode current collector facing the positive electrode layer, adjacent to the end of the positive electrode layer. By disposing the first insulating material on the end of the positive electrode layer, when the tab wires extending from the negative electrode current collectors of each cell structure are assembled to function as a battery, the tab wires are bent to avoid contact with the positive electrode end, thereby suppressing short circuits, and the occurrence of cracks due to volume changes accompanying repeated charging and discharging can be suppressed, making it possible to suppress short circuits due to cracks.

[0089] The shape of the first insulating material is not limited as long as it is provided at the end of the positive electrode layer. The size of the first insulating material is not particularly limited, and it may be any material that has a thickness equal to or less than the thickness of the positive electrode layer in the stacking direction of the electrode body, abuts against a part or all of the end face of the positive electrode layer in the extension direction of the electrode body, and is disposed at the end of the positive electrode layer.

[0090] The material of the first insulating material is not particularly limited as long as it exhibits insulating properties, and may be a so-called insulator other than a semiconductor or a conductor. The material of the first insulating material can be appropriately selected depending on the characteristics to be added to the insulating properties.

[0091] Examples of materials for the first insulating material include polypropylene, alumina, anodized aluminum, boehmite, zirconia, aluminum nitride, and silicon nitride.

[0092] The first insulating material may have a thickness in the stacking direction of the electrode body of the all-solid-state battery of the present disclosure that decreases with increasing distance from the end adjacent to the positive electrode layer in the extending direction of the electrode body. The first insulating material having such a shape has a slope as shown in FIG. 4, for example, and a void is formed in the slope. The second insulating material of the present disclosure can be disposed in the void region, so that the generation of pressure can be suppressed when the electrode body is pressed or laminated.

[0093] The manufacturing method of the first insulating material is not particularly limited, and for example, the first insulating material can be manufactured by applying a slurry containing a material of the first insulator onto a positive electrode current collector on which a positive electrode layer is formed, and drying the slurry.

[0094] [Second insulating material] The second insulating material is provided between the negative electrode current collector and the solid electrolyte layer, at a portion facing an end of the solid electrolyte layer and an end of the first insulating material, and is disposed in contact with the solid electrolyte layer such that a creepage distance from a surface of the negative electrode current collector facing the negative electrode layer to a surface of the positive electrode current collector facing the positive electrode layer is greater than the linear distance.

[0095] The all-solid-state battery of the present disclosure has the above-mentioned configuration, and when the tab wires extending from the negative electrode current collectors of the respective cell structures are assembled to function as a battery, even if the spatial distance between the tab wires and the positive electrode current collector is shortened due to bending of the tab wires, insulation can be ensured because the creepage distance from the surface of the negative electrode current collector on the negative electrode layer side to the surface of the positive electrode current collector on the positive electrode layer side is large.

[0096] The second insulating material may be a laminate including an adhesive layer and an insulating layer. The adhesive layer may be disposed on the negative electrode current collector side, and the insulating layer may be disposed on the solid electrolyte layer side. The second insulating material having such a configuration allows the adhesive layer to attach the second insulating material to a desired position on the electrode assembly. Such a second insulating material may be in the form of a tape having a release paper on the adhesive layer side, for example.

[0097] When the second insulating material is a laminate including an adhesive layer and an insulating layer, the material of the adhesive layer is not particularly limited and may be made of a known material. Among them, an acrylic adhesive layer is preferable because it is a material that is unlikely to cause an electrochemical reaction during charging and discharging. Also, the material of the insulating layer is not particularly limited and may be made of a known material. Among them, A material containing polyethylene is preferable because it is a material that is unlikely to undergo electrochemical reactions during charging and discharging.

[0098] The manufacturing method of the second insulating material is not particularly limited, and it can be manufactured, for example, by applying a slurry containing the material for the adhesive layer onto a base material with a release paper and drying it to form an adhesive layer, and then applying a slurry containing the material for the insulating layer onto the formed adhesive layer and drying it.

[0099] <Manufacturing method for all-solid-state batteries> The manufacturing method of the all-solid-state battery of the present disclosure is not particularly limited, and can be a known method. For example, a negative electrode layer, an intermediate layer, a solid electrolyte layer, and a positive electrode layer are laminated in this order, and a first insulating material is formed on both ends of the positive electrode layer. Then, a second insulating material is attached to a desired position with a desired size, so that a cell structure can be manufactured. After the cell structure is manufactured, a plurality of layers may be laminated, and then optionally pressed to be integrated.

[0100] Although a preferred embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment, and any modification or improvement that can achieve the object of the present invention is included in the present invention. [Explanation of symbols]

[0101] 1, 11, 12, 13, 14 All-solid-state battery 2a, 2b, 12a, 12b, 22a, 22b, 32a, 32b, 42a Negative electrode current collector 3a, 3b, 13a, 13b, 23a, 23b, 33a, 33b, 43a Lithium metal layer (negative electrode layer) 40, 140, 240, 340, 440 Positive electrode current collector 5a, 5b, 15a, 15b, 25a, 25b, 35a, 35b, 45a Positive electrode active material layer (positive electrode layer) 6a, 6b, 16a, 16b, 26a, 26b, 36a, 36b, 46a Solid electrolyte layer 7a, 7b, 17a, 17b, 27a, 27b, 37a, 37b, 47a Intermediate layer 8a, 8b, 8c, 8d, 18c, 18d, 28c, 28d, 38c, 38d, 48c 1st Insulation 19a, 19b, 29a, 29b, 39a, 39b, 49a Second insulating material 491 Adhesive layer 492 Insulating Layer L Stacking direction of electrode body a) Region of the second insulating material protruding from the solid electrode layer (region that contributes to the creepage distance from the surface of the negative electrode current collector on the negative electrode layer side to the surface of the positive electrode current collector on the positive electrode layer side) b Linear distance from the surface of the negative electrode layer side of the negative electrode current collector to the surface of the positive electrode layer side of the positive electrode current collector c) Distance from the end of the first insulating material adjacent to the positive electrode active material layer (positive electrode layer) in the extending direction of the electrode body

Claims

1. An all-solid-state battery including an electrode assembly in which a positive electrode current collector, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode current collector are laminated in this order, the positive electrode current collector includes a first insulating material on a surface on the positive electrode layer side, the first insulating material being adjacent to an end of the positive electrode layer; the solid electrolyte layer is disposed in contact with the positive electrode layer and the first insulating material; a second insulating material is provided between the negative electrode current collector and the solid electrolyte layer and in a portion facing an end of the solid electrolyte layer and an end of the first insulating material; the second insulating material is disposed in contact with the solid electrolyte layer such that a creepage distance from a surface of the negative electrode current collector on the negative electrode layer side to a surface of the positive electrode current collector on the positive electrode layer side is greater than the linear distance. All-solid-state battery.

2. 2. The all-solid-state battery according to claim 1, wherein the thickness of the first insulating material in a stacking direction of the electrode body decreases as the distance from an end portion adjacent to the positive electrode layer increases in an extension direction of the electrode body.

3. The all-solid-state battery according to claim 1 , wherein the second insulating material is disposed so as to overlap an end of the negative electrode layer in an extension direction of the electrode body.

4. The all-solid-state battery according to claim 3 , wherein at least a portion of the second insulating material is disposed in contact with the negative electrode current collector.

5. the electrode body includes an intermediate layer between the solid electrolyte layer and the negative electrode layer, 3. The all-solid-state battery according to claim 1, wherein, in an extension direction of the electrode body, an end of the intermediate layer is disposed at substantially the same position as an end of the negative electrode layer or an end of the second insulating material, or is disposed more inward than the end of the negative electrode layer or the end of the second insulating material.

6. The all-solid-state battery according to claim 5 , wherein at least a portion of the second insulating material is disposed in contact with the intermediate layer.

7. 3. The all-solid-state battery according to claim 1, wherein an end of the solid electrolyte layer is located at substantially the same position as an end of the first insulating material in an extending direction of the electrode body.

8. the second insulating material is a laminate including an adhesive layer and an insulating layer, the adhesive layer is disposed on the negative electrode current collector side, The all-solid-state battery according to claim 1 , wherein the insulating layer is disposed on the solid electrolyte layer side.

9. The adhesive layer is an acrylic adhesive layer, The all-solid-state battery of claim 8 , wherein the insulating layer comprises polyethylene.

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