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

Abstract

The problem of this invention is to provide a solid-state battery with improved safety. To solve this problem, a solid-state battery is provided, comprising a stack 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 stacked sequentially. The negative electrode active material layer comprises at least one of lithium metal and lithium alloy. An intermediate layer is arbitrarily stacked between the negative electrode active material layer and the solid electrolyte layer. The stacked surface of the negative electrode active material layer is covered by the solid electrolyte layer or the intermediate layer. The outer edge of the negative electrode active material layer in a direction orthogonal to the stacking direction of the stack is covered by a first insulating member. The outer edge of the positive electrode active material layer in a direction orthogonal to the stacking direction of the stack is covered by a second insulating member. When the length obtained by subtracting the length from the center of the stack to the outer end of the first insulating member in the direction orthogonal to the stacking direction is denoted as c, c > 0.

Description

Technical Field

[0001] This invention relates to a solid-state battery and a method for manufacturing a solid-state battery. Background Technology

[0002] In recent years, research and development on rechargeable batteries has been underway to help improve energy efficiency, in order to ensure that more people have access to affordable, reliable, sustainable and advanced energy.

[0003] As such secondary batteries, solid-state batteries with a solid electrolyte layer disposed between the positive and negative electrode layers are known. As solid-state batteries, lithium metal batteries with lithium metal or lithium alloys as the negative electrode active material are known.

[0004] Patent document 1 discloses the following technology: covering the periphery of the positive electrode active material layer and the negative electrode active material layer of a solid-state battery such as a lithium metal battery with an elastic component, so that even if the solid electrolyte layer is pressed during manufacturing, the breakage of the solid electrolyte layer can be suppressed.

[0005] [Existing Technical Documents]

[0006] (Patent Documents)

[0007] Patent Document 1: International Publication No. 2023 / 057811 Summary of the Invention

[0008] [The problem the invention aims to solve]

[0009] Furthermore, lithium metal batteries are susceptible to short circuits due to the potential for lithium metal or lithium alloys to melt at high temperatures. Therefore, it is crucial to prevent these melted lithium metals or alloys from contacting the positive electrode and causing a short circuit, thereby improving the safety of lithium metal batteries. As disclosed in Patent Document 1, it is generally believed that covering the periphery of both the positive and negative electrode active material layers can, to some extent, prevent short circuits in lithium metal batteries. However, molten lithium metal or lithium alloys can still leak out through minute gaps, thus requiring technologies to further enhance the safety of lithium metal batteries.

[0010] The present invention was made in view of the above circumstances, and its object is to provide a solid-state battery with improved safety.

[0011] [Technical means to solve the problem]

[0012] (1) A solid-state battery having a stack 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 stacked in sequence, wherein the negative electrode active material layer comprises at least one of lithium metal and lithium alloy, an intermediate layer may be arbitrarily stacked between the negative electrode active material layer and the solid electrolyte layer, the stacked surface of the negative electrode active material layer is covered by the solid electrolyte layer or the intermediate layer, the outer edge of the negative electrode active material layer in a direction orthogonal to the stacking direction of the stack is covered by a first insulating member, the outer edge of the positive electrode active material layer in a direction orthogonal to the stacking direction of the stack is covered by a second insulating member, and when the length obtained by subtracting the length from the center of the stack to the outer end of the first insulating member in the direction orthogonal to the stacking direction is c, c > 0.

[0013] (2) According to the solid-state battery of (1), when the length obtained by subtracting the length from the center of the aforementioned stack to the inner end of the aforementioned first insulating member from the length of the aforementioned stack to the inner end of the aforementioned second insulating member in a direction orthogonal to the aforementioned stacking direction is d, d > 0.

[0014] (3) According to the solid-state battery described in (2), when the length of the first insulating component is set as b and the length of the second insulating component is set as a in a direction orthogonal to the aforementioned stacking direction, a = b + c + d.

[0015] (4) The solid-state battery according to any one of (1) to (3), wherein, in a direction orthogonal to the aforementioned stacking direction, the length of the aforementioned negative electrode active material layer is longer than the length of the aforementioned positive electrode active material layer.

[0016] (5) According to the solid-state battery described in (2), in a direction orthogonal to the aforementioned stacking direction, the length Ln from the center of the aforementioned stack to the outer end of the aforementioned negative electrode active material layer, minus the length Lp from the center of the aforementioned stack to the outer end of the aforementioned positive electrode active material layer, satisfies d < Ln - Lp.

[0017] (6) The solid-state battery according to any one of (1) to (5), wherein the length of the first insulating member in the stacking direction is a length greater than or equal to the length of the negative electrode active material layer in the stacking direction.

[0018] (7) The solid-state battery according to any one of (1) to (6), wherein the aforementioned intermediate layer is stacked between the aforementioned negative electrode active material layer and the aforementioned solid electrolyte layer.

[0019] (8) The solid-state battery according to any one of (1) to (7), wherein the first insulating component and the second insulating component both comprise ceramic material.

[0020] (9) The solid-state battery according to any one of (1) to (8), wherein the first insulating component and the second insulating component both comprise aluminum oxide.

[0021] (10) The solid-state battery according to any one of (1) to (9), wherein the first insulating component and the second insulating component both comprise aluminum oxide and fluorinated resin.

[0022] (11) The solid-state battery according to any one of (1) to (10), wherein the first insulating component and the second insulating component are made of the same material.

[0023] (12) A method for manufacturing a solid-state battery, which is the method for manufacturing a solid-state battery according to any one of (1) to (11), comprising a first step:

[0024] A negative electrode layer is obtained by coating and forming the first insulating component around the aforementioned negative electrode active material layer, wherein the negative electrode active material layer is formed on the aforementioned negative electrode current collector layer at approximately equal intervals.

[0025] (13) The method for manufacturing a solid-state battery according to (12) includes a second step after the first step: forming the solid electrolyte layer or the intermediate layer and the solid electrolyte layer on the negative electrode layer to obtain a laminated intermediate; and a third step after the third step: cutting the laminated intermediate in a straight line along the lamination direction.

[0026] (The effect of the invention)

[0027] According to the present invention, a solid-state battery with higher safety can be provided. Attached Figure Description

[0028] Figure 1 This is a cross-sectional schematic diagram showing the structure of a solid-state battery according to the first embodiment of the present invention.

[0029] Figure 2 This is a cross-sectional schematic diagram showing the structure of a solid-state battery according to the first embodiment of the present invention.

[0030] Figure 3 This is a diagram illustrating a method for manufacturing a solid-state battery according to an embodiment of the present invention.

[0031] Figure 4 This is a cross-sectional schematic diagram showing the structure of a solid-state battery according to the second embodiment of the present invention.

[0032] Figure 5 This is a cross-sectional schematic diagram showing the structure of a solid-state battery according to the third embodiment of the present invention. Detailed Implementation

[0033] [First Implementation Method]

[0034] Solid-state batteries

[0035] Figure 1 and Figure 2 This is a schematic cross-sectional view illustrating the structure of a solid-state battery 1 manufactured by the solid-state battery manufacturing method of this embodiment. In each figure, the Y direction represents the stacking direction of each layer. The Z direction represents the direction orthogonal to the stacking direction and extending of the current collector tabs (hereinafter, negative electrode tab 21a and positive electrode tab 31a). The X direction represents the direction orthogonal to both the Y and Z directions. Figure 1 This is a schematic diagram showing a cross section of the solid-state battery 1 that is orthogonal to the Z direction mentioned above. Figure 2 This is a schematic diagram showing a cross-section of the solid-state battery 1 orthogonal to the X direction mentioned above. The following figures are schematic representations of the structures for illustrative purposes, and the dimensions of each structure do not faithfully reflect the actual dimensions.

[0036] like Figure 1 As shown, the solid-state battery 1 comprises a stack of a negative electrode current collector layer 22, a negative electrode active material layer 21, a solid electrolyte layer 4, a positive electrode active material layer 31, and a positive electrode current collector layer 32 stacked sequentially. The outer edge of the negative electrode active material layer 21 in a direction orthogonal to the stacking direction is covered by a first insulating member 7, and the outer edge of the positive electrode active material layer 31 in a direction orthogonal to the stacking direction is covered by a second insulating member 6. An intermediate layer 5 may also be arbitrarily stacked between the negative electrode active material layer 21 and the solid electrolyte layer 4. The stacked surface of the negative electrode active material layer 21 is covered by the negative electrode current collector layer 22 and the intermediate layer 5 or the solid electrolyte layer 4, and the outer edge of the negative electrode active material layer 21 (all surfaces except the stacked surface) is covered by the first insulating member 7. Therefore, it is preferable that the outer surface of the negative electrode active material layer 21 is completely covered by other layers. The solid-state battery 1 is a lithium metal secondary battery having at least one of lithium metal and lithium alloy as the negative electrode active material. Even if lithium metal or lithium alloy is accidentally melted, the solid-state battery 1 of this embodiment can effectively prevent short circuits by means of the first insulating component 7 and the second insulating component 6.

[0037] (Negative electrode layer)

[0038] The negative electrode layer 2 has a negative electrode active material layer 21 and a negative electrode current collector layer 22. The negative electrode active material layer 21 is a layer containing lithium metal or a lithium alloy as the negative electrode active material. As for the aforementioned lithium metal alloy, the metal that can form an alloy with lithium is not particularly limited, and for example, one or more metals selected from the group consisting of Sn, Ag, Mg, In, Si, Al, Bi, Sb, Zn, and Cu can be listed. For example, from the viewpoint of obtaining the preferred battery performance (discharge characteristics) of the solid-state battery 1, the metal that can form an alloy with lithium is preferably Ag or Mg.

[0039] In addition to the materials described above, the negative electrode active material layer 21 may also include materials that can be contained in the negative electrode active material layer of a solid-state battery. Examples of such materials include solid electrolytes, conductive additives, and binders. Examples of conductive additives include carbon black, natural graphite, carbon fibers, and carbon nanotubes. Examples of solid electrolytes and binders include materials identical to those used in the solid electrolyte layer 4 described below.

[0040] While the negative electrode current collector layer 22 is not particularly limited, it can be made of copper, nickel, or stainless steel. Examples of possible shapes for the negative electrode current collector layer 22 include foil, plate, mesh, non-woven fabric, and foam. The negative electrode current collector layer 22 may also have other metal layers formed on the metal foil by plating or other methods. For example, forming a nickel (Ni) plating layer on a copper foil is an example. Figure 2 As shown, a portion of the negative current collector layer 22 extends in the Z direction to form the negative current collector tab 22a.

[0041] (First insulating component)

[0042] A first insulating member 7 is provided on the outer edge of the negative electrode active material layer 21 in a direction orthogonal to the stacking direction. The first insulating member 7 is arranged to cover all surfaces of the negative electrode active material layer 21 except for the stacking surface. With the first insulating member 7, even when lithium metal or lithium alloy melts at high temperatures, the outflow of molten lithium metal or lithium alloy to the outside of the negative electrode layer 2 can be suppressed. The shape of this first insulating member 7 can also be, for example, a frame shape.

[0043] The material constituting the first insulating component 7 is not particularly limited as long as it is an insulating material other than a semiconductor or conductor, but from the viewpoint of obtaining preferred heat resistance, it is preferable to include a ceramic material. Alumina is particularly preferred as the ceramic material. Examples of ceramic materials other than alumina include magnesium oxide, zirconium oxide, titanium oxide, and silicon nitride. Examples of materials other than those mentioned above include resins such as polyvinylidene fluoride (PVDF) and rubbers such as styrene butadiene rubber (SBR).

[0044] When the first insulating component 7 comprises alumina, from the viewpoint of easy layer formation, the first insulating component 7 preferably further comprises an adhesive in addition to alumina. There are no particular limitations on the adhesive, but from the viewpoint of improving the heat resistance and chemical stability of the first insulating component 7, a fluorinated resin is preferred. Examples of fluorinated resins include polyvinylidene fluoride (PVDF) and perfluoroalkoxyfluororesin (PFA). When the first insulating component 7 comprises alumina and a fluorinated resin, the mass ratio of alumina to adhesive is preferably 80:20 to 99:1, more preferably 90:10 to 99:1, and even more preferably 92:8 to 97:3.

[0045] (Positive electrode layer)

[0046] The positive electrode layer 3 comprises a positive electrode active material layer 31 and a positive electrode current collector layer 32. The positive electrode active material layer 31 is not particularly limited and can be composed of a material suitable for use as a positive electrode active material in solid-state batteries. Examples of positive electrode active materials constituting the positive electrode active material layer 31 include: LiCoO2, LiNiO2, and LiCo. x Ni y Mn z Layered positive electrode active material particles such as O2(x+y+z=1), LiVO2, and LiCrO2; LiMn2O4, Li(Ni) 0.25 Mn 0.75 Spinel-type positive electrode active materials such as Li₂O₄, LiCoMnO₄, and Li₂NiMn₃O₈; olivine-type positive electrode active materials such as LiCoPO₄, LiMnPO₄, and LiFePO₄; solid solution oxides (Li₂MnO₃-LiMO₂ (M is Co, Ni, etc.)); conductive polymers such as polyaniline and polypyrrole; sulfides such as Li₂S, CuS, Li-Cu-S compounds, TiS₂, FeS, MoS₂, and Li-Mo-S compounds; and mixtures of sulfur and carbon, etc. The above-mentioned positive electrode active materials may use one or more of the above materials.

[0047] In addition to the materials mentioned above, the positive electrode active material layer 31 may also contain materials that can be contained in the positive electrode active material layer of a solid-state battery, such as solid electrolyte, conductive additives, and binders. Examples of such materials include those that are the same as those contained in the negative electrode active material layer 21.

[0048] The positive electrode current collector layer 32 is not particularly limited, and can be made of materials such as aluminum, stainless steel, or conductive carbon (graphite, carbon nanotubes, etc.). Examples of possible shapes for the positive electrode current collector layer 32 include foil, plate, mesh, non-woven fabric, and foam. Figure 2 As shown, a portion of the positive current collector layer 32 extends in the Z direction to form the positive current collector tab 32a.

[0049] (Second insulating component)

[0050] A second insulating member 6 is provided on the outer edge of the positive electrode active material layer 31 in a direction orthogonal to the stacking direction. The second insulating member 6 can prevent short circuits in the solid-state battery 1 and improve its strength. The shape of the second insulating member 6 may also be, for example, frame-shaped. The second insulating member 6 may also abut against a portion of the stacking surface of the positive electrode current collector layer 32 and has a gap for the positive electrode current collector tab 32a to extend.

[0051] Materials constituting the second insulating component 6 may be the same as those constituting the first insulating component 7. Both the first insulating component 7 and the second insulating component 6 preferably comprise alumina. Both the first insulating component 7 and the second insulating component 6 preferably comprise alumina and a fluorinated resin. The second insulating component 6 is preferably made of the same material as the first insulating component 7.

[0052] (Solid electrolyte layer)

[0053] In this embodiment, the solid electrolyte layer 4 is stacked between the intermediate layer 5 and the positive electrode layer 3. Figure 1 The diagram shows a solid electrolyte layer 4 stacked between the intermediate layer 5 and the positive electrode layer 3, but the number of layers of the solid electrolyte layer 4 between the intermediate layer 5 and the positive electrode layer 3 is not limited to one. For example, the solid electrolyte layer 4 can have two layers or more. When the solid-state battery 1 does not have an intermediate layer 5, the solid electrolyte layer 4 can also be stacked between the negative electrode layer 2 and the positive electrode layer 3. The solid electrolyte layer 4 contains a solid electrolyte material. There are no particular limitations on the solid electrolyte material; examples include sulfide solid electrolyte materials, oxide solid electrolyte materials, halide solid electrolytes, inorganic solid electrolytes such as lithium salts, and polymer-based solid electrolytes such as polyethylene oxide. One of the above solid electrolyte materials can be used, or two or more can be used in combination.

[0054] In addition to the solid electrolyte material described above, the solid electrolyte layer 4 may also include a binder. Examples of binders include: fluorinated resins, nitrile polymers, polyester polymers, acrylic polymers, cellulose polymers, styrene polymers, styrene-butadiene polymers, vinyl acetate polymers, and urethane polymers. One of these binders may be used alone, or two or more may be used in combination.

[0055] (Intermediate layer)

[0056] Intermediate layer 5 is arbitrarily disposed between negative electrode layer 2 and solid electrolyte layer 4. Intermediate layer 5 is a lithium-ion conductive layer. Intermediate layer 5 has the function of uniformly depositing lithium metal (dendritic crystals). The number of intermediate layers 5 is not particularly limited.

[0057] The materials constituting the intermediate layer 5 are not particularly limited, and examples include metals that can form alloys with lithium and amorphous carbon. Examples of metals that can form alloys with lithium include tin (Sn), silicon (Si), zinc (Zn), magnesium (Mg), gold (Au), platinum (Pt), palladium (Pd), silver (Ag), aluminum (Al), bismuth (Bi), antimony (Sb), and indium (In). These metals can also be composited with carbon. Metals that can form alloys with lithium can also be nanoparticles. Examples of amorphous carbon include acetylene black, furnace black, Ketjen black, coke, and activated carbon. Amorphous carbon can be easily graphitized carbon (soft carbon), difficult-to-graphitize carbon (hard carbon), carbon nanotubes (CNTs), fullerenes, and graphene. In addition to the above materials, the intermediate layer 5 may also contain a binder. The binder can be the same material that can be contained in the solid electrolyte layer 4.

[0058] The preferred configuration and dimensions of each layer are described below. In the following description, a cross-sectional view orthogonal to the Z-direction of solid-state battery 1 is used. Figure 1 This will be explained. For the cross-sectional view of solid-state battery 1 orthogonal to the X direction, i.e. Figure 2 The same explanation can be applied. In the solid-state battery 1 of this embodiment, the negative electrode layer 2, the intermediate layer 5, and the solid electrolyte layer 4, which include the first insulating member 7, have the same length in the X direction (a direction orthogonal to the stacking direction), and their end faces are aligned. The positive electrode layer 3, which includes the second insulating member 6, is longer than the above-mentioned layers in the X direction, and its two end faces extend further outward in the X direction than the above-mentioned layers. The same applies in the Z direction.

[0059] like Figure 1As shown, in the X direction, when the length obtained by subtracting the length from the center of the laminate to the outer end of the second insulating member 6 from the length from the center of the laminate to the outer end of the first insulating member 7 is denoted as c, c > 0. That is, in the X direction, the outer end of the first insulating member 7 is closer to the inner side of the laminate than the outer end of the second insulating member 6. By ensuring c > 0, the distance (surface distance) between the ends of the negative and positive electrodes can be increased, thereby reducing the possibility of a short circuit in the solid-state battery 1. During the manufacturing process of the solid-state battery 1, burrs may be generated on the cut surfaces of each layer when the layers are cut. With the above structure, even in the case of burrs, the possibility of a short circuit in the solid-state battery 1 can be reduced. In addition, in this specification, the center of the laminate refers to the point on the axis of symmetry C in each cross-sectional view.

[0060] When the length of the negative current collector layer 22 in the X direction (excluding the length of the negative current collector tab 22a, and the same applies below) is 100, c is preferably 0.2 or more and 2.0 or less, more preferably 0.3 or more and 1.7 or less, and even more preferably 0.5 or more and 1.5 or less. If c is too small, the possibility of a short circuit in the solid-state battery 1 will increase relatively. If c is too large, the disadvantage of a decrease in the energy density of the solid-state battery 1 will be more significant than the effect of improving the safety of the solid-state battery 1.

[0061] The length of the negative electrode active material layer 21 in the X direction is preferably longer than the length of the positive electrode active material layer 31 in the X direction. This increases the negative electrode capacity, thereby improving the energy density of the solid-state battery 1.

[0062] In the X direction, the length d obtained by subtracting the length from the center of the laminate to the inner end of the first insulating member 7 from the length from the center of the laminate to the inner end of the second insulating member 6 is preferably d > 0. As described above, the length of the negative electrode active material layer 21 in the X direction is preferably longer than the length of the positive electrode active material layer 31 in the X direction. In this case, d > 0 is required. If d < 0, and the end of the positive electrode active material layer 31 in the X direction is located further out of the laminate than the end of the negative electrode active material layer 21 in the X direction, the possibility of a short circuit in the solid-state battery 1 increases compared to the case where d > 0. Specifically, when d < 0, lithium dendrites are more likely to form at the ends of the lithium metal or lithium alloy constituting the negative electrode active material layer 21 during charging of the solid-state battery 1, increasing the possibility of a short circuit. Therefore, by having d > 0, the possibility of a short circuit in the solid-state battery 1 can be reduced.

[0063] When the length of the negative electrode current collector layer 22 in the X direction is 100, d is preferably 0.1 or more and 3.0 or less, more preferably 0.5 or more and 2.0 or less. If d is too small, the possibility of a short circuit in the solid-state battery 1, as described above, will increase relatively. If d is too large, when the size of the positive electrode active material layer 31 remains unchanged, it may be impossible to sufficiently ensure the length b or length c of the first insulating member 7 in the X direction. In this case, the possibility of a short circuit in the solid-state battery 1 will increase relatively. To avoid the above situation, for example, increasing a can be considered, but this will lead to a decrease in the energy density of the solid-state battery 1.

[0064] In the X direction, the length Ln from the center of the laminate to the outer end of the negative electrode active material layer 21, minus the length Lp from the center of the laminate to the outer end of the positive electrode active material layer 31, is preferably d < Ln - Lp. This reduces the possibility of short circuit in the solid-state battery 1 and improves its energy density.

[0065] When the length of the first insulating component 7 in the X direction is ( Figure 1 The length of the first insulating member 7 on one end side in the X direction is b, and the length of the second insulating member 6 in the X direction is ( Figure 1 When the length of the second insulating member 6 on one end side in the X direction is a, it is preferably a = b + c + d. Therefore, it is preferable to achieve a configuration where c > 0 for each layer, thereby better suppressing short circuits in the solid-state battery 1 and improving the energy density of the solid-state battery 1.

[0066] From the viewpoint of reducing the possibility of short circuit in the solid-state battery 1, when the length of the negative electrode current collector layer 22 in the X direction is 100, the length b of the first insulating member 7 in the X direction is preferably 0.5 or more. No particular upper limit is imposed, but from the viewpoint of energy density, it can, for example, be 2.0 or less.

[0067] The length of the first insulating component 7 in the Y direction (stacked direction) is preferably a length greater than or equal to the length of the negative electrode active material layer 21 in the Y direction. This can suppress the leakage of molten lithium metal or lithium alloy to the outside.

[0068] <Solid-State Battery Manufacturing Method>

[0069] The following describes a method for manufacturing a solid-state battery 1 according to this embodiment. The method includes a first step: forming a first insulating member 7 around a negative electrode active material layer 21 by coating, thereby obtaining a negative electrode layer, wherein the negative electrode active material layer 21 is formed on a negative electrode current collector layer 22 at approximately equal intervals. Furthermore, it is preferable to include a second step after the first step: forming a solid electrolyte layer 4, or an intermediate layer 5 and a solid electrolyte layer 4, on the negative electrode active material layer 21 to obtain a laminate; and a third step after the second step: linearly cutting the laminate along the lamination direction.

[0070] Figure 3 This diagram schematically illustrates a method for manufacturing a solid-state battery 1 according to this embodiment, and shows the negative electrode layer 2 as viewed from the stacking direction during the manufacturing process. The method for manufacturing the solid-state battery 1 according to this embodiment includes, for example, a method of fabricating multiple negative electrode layers 2 on a manufacturing line. In a first step, a first insulating member 7 is formed around a negative electrode active material layer 21 by coating, the negative electrode active material layers 21 being formed on a negative electrode current collector layer 22 at approximately equal intervals. This facilitates the formation of the first insulating member 7 in close contact around the negative electrode active material layer 21, and makes it easy to ensure that the lengths of the negative electrode active material layer 21 and the first insulating member 7 are consistent in the stacking direction. In the first step, for example, a composition for forming the first insulating member 7 is coated around the negative electrode active material layer 21 except for the portion of the negative electrode current collector tab 22a, and then hardened by methods such as drying.

[0071] In the second step, an intermediate layer 5 is arbitrarily formed on the negative electrode layer 2, and then a solid electrolyte layer 4 is formed, thereby forming a laminated intermediate. As a method for forming the intermediate layer 5 and the solid electrolyte layer 4, for example, the following method can be used: dispersing the materials constituting each layer in a solvent to prepare a slurry, coating the slurry onto a specified area, and then drying it. Alternatively, the layers formed on the transfer sheet can be transferred instead of the above method.

[0072] In the third step, for example along Figure 3 The cutting line L in the process cuts the laminated intermediate obtained in the second step along the Y direction in a straight line to a specified size. This ensures that the end faces of the laminated intermediate are uniformly aligned. Therefore, manufacturing deviations can be suppressed, and quality improved.

[0073] In the manufacturing method of solid-state battery 1, any known steps may be included as a manufacturing method of solid-state battery other than those described above.

[0074] The first embodiment of the present invention has been described above. Other embodiments of the present invention will be described below. For structures identical to the first embodiment described above, the same reference numerals will be used in the drawings, and descriptions will be omitted.

[0075] [Second Implementation]

[0076] Figure 4 This refers to the structure of the solid-state battery 1a in this embodiment, equivalent to... Figure 1 A schematic diagram is shown. In the solid-state battery 1a, in the direction orthogonal to the stacking direction (X direction), the negative electrode layer 2, including the first insulating member 7, has the shortest length. The intermediate layer 5 and the solid electrolyte layer 4 have the same length in the X direction and their end faces are aligned. The positive electrode layer 3, including the second insulating member 6, is longer than the above layers in the X direction, and its two end faces extend further outward than the above layers. The same situation applies in the Z direction.

[0077] Solid-state battery 1a is obtained by sequentially stacking a solid electrolyte layer 4 and an intermediate layer 5 on a positive electrode layer 3 containing a second insulating member 6, and finally stacking a negative electrode layer 2 containing a first insulating member 7 on top of the aforementioned layers. Therefore, a step difference may occur between the negative electrode layer 2 containing the first insulating member 7 and the solid electrolyte layer 4 and intermediate layer 5. That is, when the length obtained by subtracting the length from the outer end of the solid electrolyte layer 4 and intermediate layer 5 from the length from the outer end of the first insulating member 7 from the center of the stack is denoted as e, e ≥ 0. In this case, it is preferable to design each structure in the same manner as the solid-state battery 1 of the first embodiment described above, but preferably a = b + c + d + e. Thus, it is preferable to achieve a configuration where c > 0 for each layer.

[0078] Since the negative electrode layer 2 is fabricated separately as described above, the manufacturing method of the solid-state battery 1a does not include the second step described above. In the third step, the negative electrode layer 2 is simply cut in a straight line along the Y direction to a predetermined size. An intermediate layer 5 is stacked on the solid electrolyte layer 4 and cut in a straight line along the Y direction with the end faces aligned. Subsequently, the laminate formed by stacking the solid electrolyte layer 4 and the intermediate layer 5 is stacked on the positive electrode layer 3, and finally, the negative electrode layer 2 is stacked on the side of the intermediate layer 5. All other aspects are the same as in the first embodiment.

[0079] [Third Implementation Method]

[0080] Figure 5 This describes the structure of the solid-state battery 1b in this embodiment, equivalent to... Figure 1A schematic diagram is shown. In the solid-state battery 1a, in the direction orthogonal to the stacking direction (X direction), the negative electrode layer 2, including the first insulating member 7, has the shortest length. The intermediate layer 5 is longer than the negative electrode layer 2 in the X direction. The solid electrolyte layer 4 and the positive electrode layer 3, including the second insulating member 6, have the same length in the X direction and their end faces are aligned. Furthermore, the solid electrolyte layer 4 and the positive electrode layer 3, including the second insulating member 6, are longer than the aforementioned layers in the X direction, and their end faces extend further outward than the aforementioned layers. The same applies in the Z direction.

[0081] Similar to solid-state battery 1a, solid-state battery 1b is obtained by sequentially stacking a solid electrolyte layer 4 and an intermediate layer 5 on a positive electrode layer 3 containing a second insulating member 6, and finally stacking a negative electrode layer 2 containing a first insulating member 7 on top of the aforementioned layers. Therefore, a step difference may occur between the negative electrode layer 2 containing the first insulating member 7 and the intermediate layer 5. That is, when the length obtained by subtracting the length from the outer end of the intermediate layer 5 to the center of the stack to the outer end of the first insulating member 7 is e, e ≥ 0. In this case, it is also preferable to design each structure in the same manner as the solid-state battery 1 of the first embodiment described above, but preferably a = b + c + d + e. Thus, it is preferable to achieve a configuration where c > 0 for each layer.

[0082] Since the negative electrode layer 2 is fabricated separately as described above, the manufacturing method of the solid-state battery 1b does not include the second step described above. In the third step, the negative electrode layer 2 is simply cut in a straight line along the Y direction to a predetermined size. A solid electrolyte layer 4 is stacked on the positive electrode layer 3 and cut in a straight line along the Y direction with the end faces aligned. Subsequently, an intermediate layer 5 is stacked on the side of the solid electrolyte layer 4, and finally, the negative electrode layer 2 is stacked on the side of the intermediate layer 5. All other aspects are the same as in the first embodiment.

[0083] The preferred embodiments of the present invention have been described above. The present invention is not limited to the above embodiments, and appropriate modifications can be made without impairing the effects of the present invention.

[0084] Figure Labels

[0085] 1: Solid-state batteries

[0086] 2: Negative electrode layer

[0087] 22: Negative electrode current collector layer

[0088] 3: Positive electrode layer

[0089] 31: Positive electrode active material layer

[0090] 32: Positive current collector layer

[0091] 4: Solid electrolyte layer

[0092] 5: Intermediate layer

[0093] 6: Second insulating component

[0094] 7: First insulating component.

Claims

1. A solid-state battery comprising a stack 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 sequentially stacked. The aforementioned negative electrode active material layer includes at least one of lithium metal and lithium alloy. An intermediate layer may optionally be stacked between the aforementioned negative electrode active material layer and the aforementioned solid electrolyte layer. The aforementioned negative electrode active material layer is covered by the aforementioned solid electrolyte layer or the aforementioned intermediate layer. The outer edge of the aforementioned negative electrode active material layer in a direction orthogonal to the stacking direction of the aforementioned laminate is covered by the first insulating component. The outer edge of the aforementioned positive electrode active material layer in a direction orthogonal to the stacking direction of the aforementioned laminate is covered by a second insulating component. In a direction orthogonal to the aforementioned stacking direction, when the length obtained by subtracting the length from the center of the aforementioned stack to the outer end of the aforementioned second insulating member from the length from the center of the aforementioned stack to the outer end of the aforementioned first insulating member is denoted as c, c > 0.

2. The solid-state battery according to claim 1, wherein, In a direction orthogonal to the aforementioned stacking direction, when the length obtained by subtracting the length from the center of the aforementioned stack to the inner end of the aforementioned first insulating component from the length of the first insulating component, d is defined as d, d > 0.

3. The solid-state battery according to claim 2, wherein, In a direction orthogonal to the aforementioned stacking direction, when the length of the first insulating component is set as b and the length of the second insulating component is set as a, a = b + c + d.

4. The solid-state battery according to claim 1, wherein, In a direction orthogonal to the aforementioned stacking direction, the length of the aforementioned negative electrode active material layer is longer than the length of the aforementioned positive electrode active material layer.

5. The solid-state battery according to claim 2, wherein, In a direction orthogonal to the aforementioned stacking direction, the length Ln - Lp obtained by subtracting the length Lp from the length Lp from the length Ln from the length Ln from the length Lp from the length Lp of the length Ln from the length Ln from the length Lp of ... satisfies d < Ln - Lp.

6. The solid-state battery according to claim 1, wherein, The length of the aforementioned first insulating component in the aforementioned stacking direction is greater than or equal to the length of the aforementioned negative electrode active material layer in the aforementioned stacking direction.

7. The solid-state battery according to claim 1, wherein, The aforementioned intermediate layer is stacked between the aforementioned negative electrode active material layer and the aforementioned solid electrolyte layer.

8. The solid-state battery according to claim 1, wherein, Both the aforementioned first insulating component and the aforementioned second insulating component contain ceramic materials.

9. The solid-state battery according to claim 1, wherein, Both the aforementioned first insulating component and the aforementioned second insulating component contain aluminum oxide.

10. The solid-state battery according to claim 1, wherein, Both the aforementioned first insulating component and the aforementioned second insulating component contain alumina and fluorinated resin.

11. The solid-state battery according to claim 1, wherein, The aforementioned first insulating component and the aforementioned second insulating component are made of the same material.

12. A method for manufacturing a solid-state battery, as described in claim 1, comprising a first step: A negative electrode layer is obtained by coating and forming the first insulating component around the aforementioned negative electrode active material layer, wherein the negative electrode active material layer is formed on the aforementioned negative electrode current collector layer at approximately equal intervals.

13. The method for manufacturing a solid-state battery according to claim 12, wherein, The first step described above is followed by a second step: forming the aforementioned solid electrolyte layer, or the aforementioned intermediate layer and the aforementioned solid electrolyte layer, on the aforementioned negative electrode layer to obtain a laminated intermediate; and The second step described above includes a third step: cutting the aforementioned intermediate stacked body in a straight line along the stacking direction.

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