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

Abstract

The present invention relates to a solid-state battery and a manufacturing method of a solid-state battery. A solid-state battery includes a current collector, an electrode active material layer provided on at least one main surface of the current collector, an insulating layer provided on the at least one main surface of the current collector so as to be in contact with an end portion of the electrode active material layer, and a solid electrolyte layer provided on the electrode active material layer and the insulating layer, wherein a Young's modulus of the insulating layer is less than a Young's modulus of the electrode active material layer.

Description

Technical Field

[0001] This disclosure relates to solid-state batteries and methods for manufacturing said solid-state batteries. Background Technology

[0002] In recent years, secondary batteries have become increasingly important. In addition to secondary batteries containing electrolytes, solid-state batteries using solid electrolytes are under development. As an example of a solid-state battery, the all-solid-state battery has a solid electrolyte layer instead of a liquid electrolyte. Because it does not use flammable organic solvents, it simplifies safety devices and has excellent manufacturing costs and productivity.

[0003] Japanese Patent Application Publication No. 2024-025996 (JP 2024-025996 A) discloses a solid-state battery comprising a laminate containing a positive electrode layer, a negative electrode layer, and a solid electrolyte layer. In the solid-state battery disclosed in JP 2024-025996 A, a positive electrode active material layer and an edge layer (made of insulating material) adhering to the positive electrode active material layer are formed on two main surfaces of the positive electrode current collector. In the solid-state battery disclosed in JP 2024-025996 A, the edge layer adhering to the positive electrode active material layer has a Young's modulus distribution in the in-plane direction. Therefore, according to JP 2024-025996 A, stress concentration at the boundary between the edge layer and the positive electrode active material layer can be alleviated, the mechanical strength of the laminate can be improved, and degradation such as cracking and peeling within the laminate can be effectively suppressed.

[0004] Furthermore, Japanese Patent Application Publication No. 2023-107428 (JP 2023-107428 A) discloses a solid-state battery in which the positive electrode layer formed on the positive electrode current collector has an inclined surface tilted towards the positive electrode current collector, and this inclined surface is covered by an ion conductor layer with a Young's modulus lower than that of the solid electrolyte layer. According to JP 2023-107428 A, even when the positive electrode layer expands and contracts due to charging and discharging, stress concentration at the corners of the positive electrode layer on the solid electrolyte layer can be suppressed. Summary of the Invention

[0005] However, when pressure is applied in the stacking direction to a structure in which an electrode active material layer is stacked on a current collector and an insulating layer is stacked thereon, thus in contact with the electrode active material layer, there is a concern that the insulating layer may be damaged. Therefore, an object of one embodiment of this disclosure is to provide a solid-state battery and a method for manufacturing a solid-state battery that can suppress damage to the insulating layer even when pressure is applied in the stacking direction to a structure in which an electrode active material layer is stacked on a current collector and an insulating layer is stacked thereon, thus in contact with the electrode active material layer.

[0006] This disclosure, which achieves the above objectives, covers the following aspects.

[0007] <1> A solid-state battery, comprising: Current collector, An electrode active material layer disposed on at least one main surface of the current collector. An insulating layer disposed on at least one main surface of the current collector, thereby contacting the end of the electrode active material layer, and A solid electrolyte layer disposed on the electrode active material layer and the insulating layer The Young's modulus of the insulating layer is less than that of the Young's modulus of the electrode active material layer.

[0008] <2> according to <1> In the solid-state battery, the Young's modulus of the electrode active material layer divided by the Young's modulus of the insulating layer is in the range of 1.1 to 2.0.

[0009] <3> according to <1> or <2> The solid-state battery, wherein the insulating layer comprises filler.

[0010] <4> A method for manufacturing a solid-state battery, comprising: An electrode active material layer and an insulating layer are formed on at least one main surface of the current collector, such that the insulating layer is in contact with an end of the electrode active material layer. Pressure is applied to the current collector, the electrode active material layer, and the insulating layer in the stacking direction, and A solid electrolyte layer is formed on the electrode active material layer and the insulating layer. The Young's modulus of the insulating layer is less than that of the Young's modulus of the electrode active material layer.

[0011] <5> according to <4> In the manufacturing method described above, the value obtained by dividing the Young's modulus of the electrode active material layer by the Young's modulus of the insulating layer is in the range of 1.1 to 2.0.

[0012] <6> according to <4> or <5> The manufacturing method wherein the insulating layer comprises a filler.

[0013] According to one embodiment of the present disclosure, even when pressure is applied to a structure in the stacking direction in which an electrode active material layer is stacked on a current collector and an insulating layer is stacked to be in contact with the electrode active material layer, damage to the insulating layer can be suppressed. Attached Figure Description

[0014] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, wherein like symbols denote like elements, and wherein: Figure 1 is a cross-sectional view of a main part of a solid-state battery according to an embodiment of the present disclosure; and Figure 2 is a schematic top view showing an example of a position where the surface of the solid-state battery is cut along a plane parallel to the first axis direction in a top view from above. Detailed Embodiments

[0015] In the present disclosure, a numerical range represented using "to" indicates a range including the values written before and after "to" (as the minimum value and the maximum value, respectively).

[0016] Within the numerical ranges described in stages in the present disclosure, the upper limit value or the lower limit value described within a certain numerical range can be replaced with the upper limit value or the lower limit value of another numerically described range in stages. Within the numerical ranges described in the present disclosure, the upper limit value or the lower limit value described within a certain numerical range can be replaced with the value shown in the examples.

[0017] In the present disclosure, the term "process" includes not only independent processes but also processes that may be difficult to clearly distinguish from other processes, as long as the intended purpose of the process is achieved. In the present disclosure, when multiple types of substances correspond to each component, unless otherwise specified, the amount of each component refers to the total amount of the multiple types of substances.

[0018] In the present disclosure, when describing an embodiment with reference to the drawings, the configuration of the embodiment is not limited to the configuration shown in the drawings. In addition, the dimensions of the components in the drawings are conceptual, and the relative relationships between the dimensions of the components are not limited to these.

[0019] Solid-state battery

[0020] The solid-state battery of this disclosure will now be described. The solid-state battery according to this disclosure includes a current collector, an electrode active material layer disposed on at least one main surface of the current collector, an insulating layer disposed on the at least one main surface of the current collector and thus in contact with an end of the electrode active material layer, and a solid electrolyte layer disposed on the electrode active material layer and the insulating layer, wherein the Young's modulus of the insulating layer is less than the Young's modulus of the electrode active material layer. In the solid-state battery according to this disclosure, even when pressure is applied to the electrode active material layer and the insulating layer stacked on the current collector in the stacking direction (e.g., when an external force is applied in the stacking direction while the current collector, electrode layer, etc., are under a constrained state of being pressed into close contact), damage to the insulating layer can be suppressed. Furthermore, in the solid-state battery according to this disclosure, when pressure is applied in the stacking direction as described above, the stepped formation between the electrode active material layer and the insulating layer disposed on the current collector is eliminated, and the solid electrolyte layer can be suitably made to be in close contact with the electrode active material layer and the insulating layer.

[0021] like Figure 1 As shown in the illustration, a solid-state battery according to one embodiment of this disclosure includes a positive current collector 1, a positive electrode layer 2 and an insulating layer 3 disposed on two main surfaces of the positive current collector 1, a solid electrolyte layer 4 disposed on the positive electrode layer 2 and the insulating layer 3, a negative electrode layer 5 disposed on the solid electrolyte layer 4, a carbon coating 6 disposed on the negative electrode layer 5, and a negative current collector 7 disposed on the carbon coating 6. It should be noted that in... Figure 1 The solid-state battery shown is configured such that the positive electrode layer 2 and the insulating layer 3 are disposed on two main surfaces of the positive electrode current collector 1. However, the solid-state battery according to this disclosure is not limited to this configuration. For example, the solid-state battery of this disclosure may have a configuration in which the positive electrode layer 2 and the insulating layer 3 are disposed on one main surface of the positive electrode current collector 1. Furthermore, the solid-state battery of this disclosure may have the following configuration: a negative electrode layer and an insulating layer are disposed on two main surfaces or one main surface of the negative electrode current collector, a solid electrolyte layer is disposed on the negative electrode layer and the insulating layer, and a positive electrode layer and a positive electrode current collector are disposed on the solid electrolyte layer. That is, in the solid-state battery according to this disclosure, the current collector and the electrode active material layer refer to either the positive electrode current collector and the positive electrode layer, or the negative electrode current collector and the negative electrode layer.

[0022] In addition, Figure 1 In the solid-state battery shown, the positive current collector 1 has a positive current collector tab side end 1A connected to the positive current collector tab. The insulating layer 3 and the positive electrode layer 2 are arranged sequentially from the positive current collector tab side end 1A. Figure 1The solid-state battery shown has an end insulation portion 8 provided at the end of the positive current collector 1 opposite to the end 1A on the tab side of the positive current collector. It should be noted that in this disclosure, the term "stack direction" refers to the direction in which the positive current collector 1, the positive electrode layer 2, the solid electrolyte layer 4, etc., are stacked, such as... Figure 1 As indicated by the middle arrow X.

[0023] exist Figure 1 In the solid-state battery shown, the negative electrode layers 5 are each divided into two layers: a first negative electrode layer 5A located on the solid electrolyte layer 4, and a second negative electrode layer 5B located on the first negative electrode layer 5A. However, it should be noted that each negative electrode layer 5 can be a single layer, or it can have two or more sub-layers. Furthermore, in... Figure 1 In the solid-state battery shown, each negative electrode current collector 7 is divided into two layers: a first negative electrode current collector 7A located on the negative electrode layer 5, and a second negative electrode current collector 7B located on the first negative electrode current collector 7A. However, it should be noted that each negative electrode current collector 7 can be a single layer, or it can have two or more sub-layers.

[0024] exist Figure 1 In the solid-state battery shown, the positive electrode layer 2 and the insulating layer 3 are formed flush with the main surface of the positive electrode current collector 1. That is, the positive electrode layer 2 and the insulating layer 3 are connected to each other at one end face, wherein the main surface of the positive electrode layer 2 and the main surface of the insulating layer 3 are formed as a single plane. In the solid-state battery according to this disclosure, the Young's modulus of the insulating layer 3 is smaller than that of the positive electrode layer 2. Therefore, when the positive electrode layer 2 and the insulating layer 3 are disposed on the main surface of the positive electrode current collector 1, applying pressure in the stacking direction can eliminate the step between the main surface of the positive electrode layer 2 and the main surface of the insulating layer 3, thereby making them a single plane. Furthermore, in Figure 1 In the solid-state battery shown, the end of the solid electrolyte layer 4 on the positive electrode current collector tab side 1A side is located at a position overlapping with the insulating layer 3. In other words, the end of the solid electrolyte layer 4 on the positive electrode current collector tab side 1A side is located at a position not overlapping with the positive electrode layer 2, and the solid electrolyte layer 4 is formed to cover the entire surface of the positive electrode layer 2.

[0025] In addition, Figure 1 In the solid-state battery shown, the positive electrode layer 2 is formed by applying a positive electrode slurry to the main surface of the positive electrode current collector 1 and then drying it. Therefore, the end face of the positive electrode layer 2 on the tab side 1A side of the positive electrode current collector becomes an inclined surface due to sag. It should be noted that the end face of the positive electrode layer 2 opposite to the tab side 1A side of the positive electrode current collector is cut off, and therefore is not an inclined surface but a surface approximately parallel to the lamination direction. Furthermore, in Figure 1In the solid-state battery shown, after forming the positive electrode layer 2 with an inclined surface, an insulating layer 3 is formed by applying an insulating slurry containing an insulating material and drying it. Therefore, the end face of the insulating layer 3 on the positive electrode current collector tab side 1A side becomes an inclined surface due to sag.

[0026] In addition, Figure 1 In the solid-state battery shown, in a cross-sectional view taken along the stacking direction X of the positive current collector 1, positive electrode layer 2, and insulating layer 3, the end of the solid electrolyte layer 4 on the positive current collector tab side 1A side is located overlapping with the insulating layer 3. The term "cross-sectional view along the stacking direction X" refers to a cross-section of the solid-state battery taken along the stacking direction X of the observed battery stack structure, specifically a cross-section passing through the positive current collector tab side end 1A and the end opposite to the observed positive current collector tab side end 1A. More specifically, when... Figure 1 When the solid-state battery shown is a prismatic battery, the cross-sectional view along the stacking direction X can be a cross-sectional view taken from a top view along line AA, which divides the short side of the rectangle into approximately two equal parts, as shown below. Figure 2 As shown in the image. It should be noted that... Figure 2 In the middle, the AA line, which divides the rectangular shape into approximately two equal parts along the short side, passes through the end 1A of the positive current collector tab and the end insulation part 8.

[0027] In the solid-state battery constructed as described above, the Young's modulus of the insulating layer 3 is smaller than that of the positive electrode layer 2. Therefore, even when pressure is applied to the solid-state battery in the stacking direction X, damage to the insulating layer 3, particularly damage near the end face of the insulating layer 3 and damage to the boundary portion between the insulating layer 3 and the positive electrode layer 2, can be suppressed. Now, an example of applying pressure in the stacking direction X includes the following steps: wherein the positive electrode layer 2 and the insulating layer 3 are disposed on the main surface of the positive electrode current collector 1, and then the positive electrode layer 2 is compressed in the stacking direction X to densify the positive electrode layer. In this case, the Young's modulus of the insulating layer 3 is smaller than that of the positive electrode layer 2, thus damage to the insulating layer 3, particularly damage near the end face of the insulating layer 3 and damage to the boundary portion between the insulating layer 3 and the positive electrode layer 2, can also be eliminated, thereby forming a coplanar plane.

[0028] In addition, Figure 1In the solid-state battery shown, the positive electrode current collector 1, the positive electrode layer 2, the insulating layer 3, and the solid electrolyte layer 4 can be stacked sequentially. Pressure can then be applied in the direction that holds the positive electrode current collector 1, the positive electrode layer 2, the insulating layer 3, and the solid electrolyte layer 4, thereby densifying the positive electrode layer 2 and ensuring close contact between the solid electrolyte layer 4 and the positive electrode layer 2. In this case, the Young's modulus of the insulating layer 3 is also smaller than that of the positive electrode layer 2, thus suppressing damage to the insulating layer 3, particularly damage near the end face of the insulating layer 3 and damage to the boundary between the insulating layer 3 and the positive electrode layer 2.

[0029] Furthermore, the solid-state battery may also include a constraint member (although omitted in the figures) for constraining the solid-state battery in the stacking direction X. The constraint member applies constraint pressure to the electrode stack in the stacking direction X. In the solid-state battery according to this disclosure, even when the constraint pressure is applied by the constraint member, damage to the insulating layer 3, particularly damage near the end face of the insulating layer 3 and damage to the boundary portion between the insulating layer 3 and the positive electrode layer 2, can be suppressed.

[0030] Here, in the solid-state battery according to this disclosure, the value obtained by dividing the Young's modulus of the electrode active material layer by the Young's modulus of the insulating layer is preferably in the range of 1.1 to 2.0. That is, in Figure 1 In the solid-state battery shown, the Young's modulus obtained by dividing the Young's modulus of the positive electrode layer 2 by the Young's modulus of the insulating layer 3 is preferably in the range of 1.1 to 2.0. Setting the value obtained by dividing the Young's modulus of the positive electrode layer 2 by the Young's modulus of the insulating layer 3 by 1.1 or more makes it possible to more reliably suppress damage to the insulating layer 3, especially damage near the end face of the insulating layer 3 and damage to the boundary between the insulating layer 3 and the positive electrode layer 2. Furthermore, setting the value obtained by dividing the Young's modulus of the positive electrode layer 2 by the Young's modulus of the insulating layer 3 by 2.0 or less allows the solid electrolyte layer 4 disposed on the insulating layer 3 to be reliably supported. It should be noted that the Young's modulus of the insulating layer 3, the electrode active material layer, etc., can be measured according to the tensile test method of JIS G0567, which is a static test method.

[0031] Elements of solid-state batteries

[0032] Positive current collector

[0033] The positive current collector used can be any commonly used battery positive current collector. The positive current collector can be in the form of foil, plate, mesh, perforated metal, foam, etc. The positive current collector can be made of metal foil or metal mesh. In particular, metal foil is excellent in terms of ease of handling. The positive current collector can be made of multiple foil sheets. Examples of metals that can be used in the positive current collector include copper (Cu), nickel (Ni), chromium (Cr), gold (Au), platinum (Pt), silver (Ag), aluminum (Al), iron (Fe), titanium (Ti), zinc (Zn), cobalt (Co), stainless steel, etc. In particular, from the viewpoint of ensuring oxidation resistance, the positive current collector can contain Al.

[0034] Positive electrode layer

[0035] The positive electrode layer contains at least a positive electrode active material and may optionally contain an electrolyte, conductive additives, binders, etc. The positive electrode layer may also contain various types of additives. The positive electrode active material can be any known material used as a positive electrode active material for secondary batteries. Examples of positive electrode active materials may include at least one selected from various types of lithium-containing compounds, elemental sulfur, sulfur compounds, etc. The lithium-containing compound used as the positive electrode active material can be any of the following: various types of lithium-containing oxides, such as lithium cobalt oxide, lithium nickel oxide, Li... 1±α Ni 1 / 3 Co 1 / 3 Mn 1 / 3 O 2±δ Lithium manganese oxide, spinel-based lithium compounds (e.g., Li-Mn spinel with different element substitutions, whose composition is represented as Li...) 1+x Mn 2-x-y M y O4 (where M is selected from one or more of Al, Mg, Co, Fe, Ni and Zn)), lithium titanate, lithium metal phosphate (e.g., LiMPO4, where M is selected from one or more of Fe, Mn, Co and Ni), etc.

[0036] Insulation layer

[0037] There are no particular restrictions on the insulating layer, and it can have any composition, as long as it is non-conductive. For example, the insulating layer can contain fillers such as inorganic fillers and adhesives. When the insulating layer contains fillers, it can exhibit an anchoring effect on the solid electrolyte layer disposed on the insulating layer, and the insulating layer and the solid electrolyte layer can be more firmly bonded to each other. Examples of inorganic fillers include inorganic materials such as spherical silica, crystalline silica, etc., glass, alumina, calcium carbonate, zirconium silicate, calcium silicate, silicon nitride, aluminum nitride, boron nitride, beryllium oxide, zircon, zircon, forsterite, soapstone, spinel, mullite, titanium dioxide, talc, clay, mica, etc. As an example, the insulating layer can be composed of alumina and adhesives. There are no particular restrictions on the amount of filler contained in the insulating layer, and it can be, for example, 1% to 10% by volume, preferably 3% to 10% by volume, more preferably 5% to 10% by volume. Setting the amount of filler contained in the insulation layer within this range can more strongly exhibit the aforementioned anchoring effect.

[0038] The Young's modulus of the insulating layer can be appropriately adjusted by factors such as the type and content of the filler, the type and content of the binder, and other additives. This allows the Young's modulus of the insulating layer to be lower than that of the electrode active material layer (positive or negative electrode layer). Furthermore, the value obtained by dividing the Young's modulus of the electrode active material layer (positive or negative electrode layer) by the Young's modulus of the insulating layer can be set within the range of 1.1 to 2.0.

[0039] solid electrolyte layer

[0040] Examples of solid electrolyte layers include those used in semi-solid-state and all-solid-state batteries. There are no particular limitations on the thickness of the solid electrolyte layer, and it can be selected, for example, from 1 μm to 30 μm. There are no particular limitations on the type of solid electrolyte contained in the solid electrolyte layer. For example, solid electrolytes selected from those applicable to the electrode layers described above can be used. The solid electrolyte layer can be a single layer or a multilayer structure comprising two or more layers.

[0041] When a solid electrolyte is included, the solid-state battery according to this disclosure may further include an electrolyte solution in an amount of less than 10% by mass relative to the total mass of the electrolyte. When the battery according to this disclosure includes a solid electrolyte, the solid electrolyte may be a composite solid electrolyte containing both an inorganic solid electrolyte and a polymeric electrolyte. Preferably, the solid electrolyte contains at least one type of solid electrolyte selected from the group consisting of sulfide solid electrolytes, oxide solid electrolytes, and halide solid electrolytes. When the solid-state battery of this disclosure includes an electrolyte solution as the electrolyte, there are no particular limitations on the type of electrolyte solution, and any known electrolyte solution can be used. Specific examples of electrolyte solutions include liquids obtained by dissolving lithium salts such as LiPF6 and LiFSI in an organic solvent.

[0042] negative electrode layer

[0043] The negative electrode layer contains at least a negative electrode active material and may optionally contain an electrolyte, conductive additives, binders, etc. The negative electrode layer may also contain various other additives. Examples of negative electrode active materials include carbon materials, active materials containing elemental silicon (Si), metallic lithium, lithium-containing alloys, metals or alloys capable of forming alloys with lithium, oxides, transition metal nitrides, etc. Examples of carbon materials include graphite materials, amorphous carbon materials, carbon black, activated carbon, etc. Examples of active materials containing elemental Si include pure silicon, silicon alloys (e.g., alloys of Si with one or more metals selected from the group consisting of Sn, Ti, Fe, Ni, Cu, Co, and Al), porous silicon, silicon cage compounds, silicon oxides, etc.

[0044] Negative current collector

[0045] Any commonly used battery negative electrode current collector can be used as the negative electrode current collector. Furthermore, the negative electrode current collector can be in the form of foil, plate, mesh, perforated metal, foam, etc. The negative electrode current collector can be a metal foil or metal mesh, or it can be a carbon sheet. The negative electrode current collector can be made of multiple foil sheets. Examples of metals that can be used to make negative electrode current collectors include Cu, Ni, Cr, Au, Pt, Ag, Al, Fe, Ti, Zn, Co, stainless steel, etc. In particular, from the viewpoint of ensuring resistance to reduction and minimizing the likelihood of alloying with lithium, the negative electrode current collector can contain at least one selected from Cu, Ni, and stainless steel.

[0046] carbon coating

[0047] The carbon coating serves as an adhesive layer to bond the aforementioned negative electrode current collector to the negative electrode layer, and also as a conductive layer to ensure conductivity between the negative electrode current collector and the negative electrode layer. Examples of carbon materials contained in the carbon coating include graphite, amorphous carbon, carbon black, activated carbon, etc.

[0048] Constraint components

[0049] The solid-state battery of this disclosure may further include a constraint member. The constraint member applies constraint pressure to the electrode stack in the thickness direction. The constraint pressure applied in the thickness direction of the electrode stack may be, for example, 0.1 MPa or more, 1 MPa or more, or 5 MPa or more. The constraint pressure applied in the thickness direction of the electrode stack may be, for example, 100 MPa or less, 50 MPa or less, or 20 MPa or less.

[0050] Solid-state battery manufacturing method

[0051] The solid-state battery manufacturing method of this disclosure includes the following steps: forming an electrode active material layer and an insulating layer on at least one main surface of a current collector, such that the insulating layer is in contact with the end of the electrode active material layer; applying pressure to the current collector, the electrode active material layer, and the insulating layer in the stacking direction; and forming a solid electrolyte layer on the electrode active material layer and the insulating layer. In the solid-state battery manufacturing method according to this disclosure, the Young's modulus of the insulating layer is less than that of the electrode active material layer, so damage to the insulating layer can be suppressed even after undergoing the pressure application step. Furthermore, in the solid-state battery manufacturing method according to this disclosure, the pressure application step eliminates any steps formed between the electrode active material layer and the insulating layer disposed on the current collector, and the solid electrolyte layer can be suitably adhered to the electrode active material layer and the insulating layer. It should be noted that in the solid-state battery manufacturing method according to this disclosure, the electrode active material layer can be densified by the step of applying pressure in the stacking direction of the current collector, the electrode active material layer, and the insulating layer.

[0052] Furthermore, in the solid-state battery manufacturing method according to this disclosure, during the step of forming a solid electrolyte layer on the electrode active material layer and the insulating layer, pressure can be applied in the stacking direction of the current collector, the electrode active material layer, the insulating layer, and the solid electrolyte layer. Applying pressure in the stacking direction of the current collector, the electrode active material layer, the insulating layer, and the solid electrolyte layer enables the solid electrolyte layer to be firmly and tightly contacted with the electrode active material layer and the insulating layer. In this case, the Young's modulus of the insulating layer is also smaller than that of the electrode active material layer, thus suppressing damage to the insulating layer.

[0053] Regarding the manufacturing method of the solid-state battery according to this disclosure, Figure 1 The solid-state battery shown is an example. First, a positive electrode layer 2 and an insulating layer 3 are formed on the two main surfaces of the positive electrode current collector 1. Then, a solid electrolyte layer 4 is formed on the positive electrode layer 2 and the insulating layer 3, such that the end of the solid electrolyte layer overlaps with the insulating layer 3. Next, a negative electrode layer 5, a carbon coating 6, and a negative electrode current collector 7 are sequentially formed on the solid electrolyte layer 4, thereby enabling the fabrication of a solid-state battery. Figure 1The solid-state battery is shown. In this case, the positive electrode layer 2 and the insulating layer 3 are formed on the two main surfaces of the positive electrode current collector 1. Pressure is applied in the stacking direction X to clamp the positive electrode current collector 1, thereby densifying the positive electrode layer 2 formed on the two main surfaces of the positive electrode current collector 1. This also eliminates any steps formed between the positive electrode layer 2 and the insulating layer 3, allowing the positive electrode layer 2 and the insulating layer 3 to be made into the same plane. Subsequently, a solid electrolyte layer 4 is formed on the positive electrode layer 2 and the insulating layer 3. It should be noted that after the solid electrolyte layer 4 is formed, the positive electrode current collector 1 can be clamped between them by applying pressure in the stacking direction X, thereby simultaneously densifying the positive electrode layer 2 and the solid electrolyte layer 4.

[0054] Specifically, in the solid-state battery manufacturing method according to this disclosure, the Young's modulus of the insulating layer 3 is less than that of the positive electrode layer 2, thus eliminating the step formed between the positive electrode layer 2 and the insulating layer 3. Furthermore, the positive electrode layer 2 and the insulating layer 3 are formed on the same plane, allowing the solid electrolyte layer 4 to be in close contact with both the positive electrode layer 2 and the insulating layer 3. It has been confirmed that when the main surface of the positive electrode layer 2 is 10 μm lower than the main surface of the insulating layer 3, the solid electrolyte layer 4 cannot be in close contact with the positive electrode layer 2. It has also been confirmed that when the main surface of the positive electrode layer 2 is 10 μm higher than the main surface of the insulating layer 3, the solid electrolyte layer 4 cannot be in close contact with the insulating layer 3. Therefore, in the solid-state battery manufacturing method according to this disclosure, pressure is applied in the stacking direction X to clamp the positive electrode current collector 1, such that the step formed between the positive electrode layer 2 and the insulating layer 3 is less than 10 μm, preferably less than 5.0 μm, more preferably less than 3.0 μm, and even more preferably less than 1.0 μm.

[0055] Subsequently, a negative electrode layer 5 is formed on the solid electrolyte layer 4. At this time, the negative electrode layer 5 is formed such that the end of the negative electrode layer 5 on the positive electrode current collector tab side 1A side is located at a position overlapping with the solid electrolyte layer 4 and the insulating layer 3. Then, the carbon coating 6 in the laminate of the negative electrode current collector 7 and the carbon coating 6 is bonded to the negative electrode layer 5. Thus, the carbon coating 6 and the negative electrode current collector 7 can be formed on the negative electrode layer 5.

[0056] According to the solid-state battery manufacturing method disclosed in this disclosure, the Young's modulus of the insulating layer 3 is smaller than that of the positive electrode layer 2. Therefore, even when the positive electrode current collector 1, the positive electrode layer 2, and the insulating layer 3 are pressurized in the stacking direction X to densify the positive electrode layer 2, damage to the insulating layer 3, particularly damage near the end face of the insulating layer 3 and damage to the boundary portion between the insulating layer 3 and the positive electrode layer 2, can be suppressed. Furthermore, in the solid-state battery manufacturing method of this disclosure, even when the solid electrolyte layer 4 is formed on the positive electrode layer 2 and the insulating layer 3, and then compressed in the stacking direction X to clamp the positive electrode current collector 1, damage to the insulating layer 3, particularly damage near the end face of the insulating layer 3 and damage to the boundary portion between the insulating layer 3 and the positive electrode layer 2, can be suppressed.

Claims

1. A solid-state battery, comprising: Current collector; An electrode active material layer disposed on at least one main surface of the current collector; An insulating layer disposed on at least one main surface of the current collector, thereby contacting the end of the electrode active material layer; as well as A solid electrolyte layer is disposed on the electrode active material layer and the insulating layer, wherein The Young's modulus of the insulating layer is less than that of the Young's modulus of the electrode active material layer.

2. The solid-state battery according to claim 1, wherein the Young's modulus of the electrode active material layer divided by the Young's modulus of the insulating layer is in the range of 1.1 to 2.

0.

3. The solid-state battery according to claim 1, wherein the insulating layer comprises a filler.

4. A method for manufacturing a solid-state battery, the method comprising: An electrode active material layer and an insulating layer are formed on at least one main surface of the current collector, such that the insulating layer is in contact with the end of the electrode active material layer; Pressure is applied to the current collector, the electrode active material layer, and the insulating layer in the stacking direction; as well as A solid electrolyte layer is formed on the electrode active material layer and the insulating layer, wherein... The Young's modulus of the insulating layer is less than that of the Young's modulus of the electrode active material layer.

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