All-solid-state battery and method for pressurizing an all-solid-state battery

Abstract

To provide a technique during pressure application that can apply a sufficient pressure even to ends of an all-solid battery.SOLUTION: An all-solid battery 1 comprises: a power generation element 2; frame-like first insulating parts 3 that are arranged to surround outer peripheral ends of the power generation element 2 and formed of an elastic body; a pressure application mechanism 5 that applies a pressure so as to compress the power generation element 2 and the first insulating parts 3 along a lamination direction; and frame-like second insulating parts 4 that are arranged to surround the outer peripheral ends of the first insulating parts 3.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an all-solid-state battery and a method for pressurizing an all-solid-state battery.

Background Art

[0002] An all-solid-state battery is a secondary battery composed of solid materials. An all-solid-state battery usually has a solid electrolyte layer, a positive electrode layer, and a negative electrode layer as power generation elements. These are laminated so that the solid electrolyte layer is sandwiched between the positive electrode layer and the negative electrode layer.

[0003] In order for an all-solid-state battery to fully exhibit its function, each electrode layer needs to be firmly joined to the solid electrolyte layer. For this reason, an all-solid-state battery is pressurized so as to be compressed along the stacking direction, for example, during manufacturing or use.

[0004] Techniques related to pressurization during manufacturing are described in, for example, Patent Document 1. Patent Document 1 describes that when a positive electrode layer, a solid electrolyte layer, and a negative electrode layer are laminated and press-molded, a short circuit may occur between the positive electrode layer and the negative electrode layer, and the characteristics of the electric element may be impaired. And, as an invention for suppressing a short circuit, an element portion constituted by laminating a first solid electrode layer, a solid electrolyte layer having lithium ion conductivity, and a second solid electrode layer in this order is included. When the element portion is viewed in plan, an electric element is disclosed in which the outer contour line of at least one of the first solid electrode layer and the second solid electrode layer is within the outer contour line of the solid electrolyte layer.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Incidentally, the inventors have found that even when an all-solid-state battery is pressurized along the stacking direction, it is difficult to apply pressure to the ends of the all-solid-state battery. In order for the all-solid-state battery to fully perform its function, it is desirable to apply sufficient pressure to the ends as well.

[0007] Therefore, the object of the present invention is to provide a technology that can apply sufficient pressure to the ends of an all-solid-state battery when pressurized. [Means for solving the problem]

[0008] In one embodiment, the all-solid-state battery according to the present invention comprises a power generation element having a solid electrolyte layer, a first electrode layer laminated on one surface of the solid electrolyte layer, and a second electrode layer laminated on the other surface of the solid electrolyte layer; a frame-shaped first insulating portion formed of an elastic material and arranged to surround the outer peripheral end of the power generation element; a pressurizing mechanism that pressurizes the power generation element and the first insulating portion to compress them along the lamination direction; and a frame-shaped second insulating portion arranged to surround the outer peripheral end of the first insulating portion. The Young's modulus of the second insulating portion is greater than that of the first insulating portion. When pressurized by the pressurizing mechanism, the outer peripheral end of the first insulating portion abuts against the second insulating portion, and the outer peripheral end of the power generation element is pressurized by the first insulating portion. [Effects of the Invention]

[0009] According to the present invention, a technique is provided that allows sufficient pressure to be applied to the ends of an all-solid-state battery during pressurization. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic diagram showing the main parts of an all-solid-state battery according to an embodiment of the present invention. [Figure 2] Figure 2 is a schematic diagram showing the overall configuration of the all-solid-state battery according to the first embodiment. [Figure 3] Figure 3 is a schematic cross-sectional view showing a portion of the end of an all-solid-state battery according to the first embodiment. [Figure 4A]FIG. 4A is a cross-sectional view schematically showing a all-solid-state battery according to a reference example. [Figure 4B] FIG. 4B is a schematic diagram showing how pressure is applied in the all-solid-state battery according to the first embodiment. [Figure 5] FIG. 5 is a diagram showing an example of the arrangement of the first insulating portion and the second insulating portion. [Figure 6] FIG. 6 is a diagram showing another example of the arrangement of the first insulating portion and the second insulating portion. [Figure 7] FIG. 7 is a diagram showing still another example of the arrangement of the first insulating portion and the second insulating portion. [Figure 8] FIG. 8 is a diagram showing still another example of the arrangement of the first insulating portion and the second insulating portion. [Figure 9] FIG. 9 is a cross-sectional view schematically showing the configuration of the all-solid-state battery according to the second embodiment. [Figure 10] FIG. 10 is a cross-sectional view schematically showing the configuration of the all-solid-state battery according to the third embodiment. [Figure 11] FIG. 11 is a cross-sectional view schematically showing the configuration of the all-solid-state battery according to the fourth embodiment. [Figure 12] FIG. 12 is a cross-sectional view schematically showing the configuration of the all-solid-state battery according to the fifth embodiment. [Figure 13] FIG. 13 is a cross-sectional view schematically showing the configuration of the all-solid-state battery according to the sixth embodiment. [Figure 14] FIG. 14 is a cross-sectional view schematically showing the configuration of the all-solid-state battery according to the seventh embodiment. [Figure 15] FIG. 15 is a cross-sectional view schematically showing the configuration of the all-solid-state battery according to the eighth embodiment. BEST MODE FOR CARRYING OUT THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0012] First, the principle of the all-solid-state battery 1 according to the embodiment of the present invention will be described. FIG. 1 is a diagram schematically showing the main part of the all-solid-state battery 1 according to the present embodiment, and is a diagram for explaining the principle of the present embodiment.

[0013] As shown in FIG. 1, the all-solid-state battery 1 includes a power generation element 2, a pressurizing mechanism 5, a first insulating part 3, and a second insulating part 4. Although not shown in FIG. 1, the power generation element 2 has a configuration in which a first electrode layer, a solid electrolyte layer, and a second electrode layer are laminated in this order along the lamination direction. The first insulating part 3 is in a frame shape and is arranged so as to surround the outer peripheral end face of the power generation element 2. The second insulating part 4 is also in a frame shape and is arranged so as to surround the outer peripheral end face of the first insulating part 3. The Young's modulus of the second insulating part 4 is larger than the Young's modulus of the first insulating part 3. The pressurizing mechanism 5 is configured to pressurize the power generation element 2 and the first insulating part 3 along the lamination direction.

[0014] According to the above configuration, the power generation element 2 and the first insulating part 3 are pressurized along the lamination direction by the pressurizing mechanism 5. Here, since the first insulating part 3 is made of an elastic body, it is compressed by the pressurization. A force that bulges in the lateral direction (a direction perpendicular to the lamination direction) is generated in the compressed first insulating part 3. The outer peripheral end of the compressed first insulating part 3 abuts against the inner peripheral end of the second insulating part 4. Since the Young's modulus of the second insulating part 4 is smaller than the Young's modulus of the first insulating part 3, the first insulating part 3 hardly bulges outward. As a result, the force generated in the compressed first insulating part 3 mainly acts inward. As a result, the end part of the power generation element 2 is pressurized by the first insulating part 3. Therefore, sufficient pressure can be applied to the end part of the all-solid-state battery 1 where it is difficult for pressure to be applied.

[0015] The above is the explanation of the principle of the present embodiment. Next, the all-solid-state battery 1 according to the present embodiment will be specifically described.

[0016] (First Embodiment) Figure 2 is a schematic diagram showing the overall configuration of an all-solid-state battery 1 according to the first embodiment. As shown in Figure 2, this all-solid-state battery 1 has a battery cell 8, a pair of pressure plates 6, and a pair of elastic sheets 7. The battery cell 8 is generally in the form of a sheet. The pair of elastic sheets 7 are provided so as to sandwich the battery cell 8 in the stacking direction. The pair of pressure plates 6 are provided on the outside of the pair of elastic sheets 7. The pair of pressure plates 6 are bound together, for example, by a rubber band. As a result, a compressive force is applied to the battery cell 8 from the pair of pressure plates 6 through the pair of elastic sheets 7 in the stacking direction. That is, the pair of pressure plates 6 and the pair of elastic sheets 7 function as a pressurizing mechanism 5.

[0017] Figure 3 is a schematic cross-sectional view showing a portion of the end of the all-solid-state battery 1. Figure 3 also shows the internal structure of the battery cell 8. As shown in Figure 3, the battery cell 8 has an outer casing 9, multiple power generation elements 2, multiple first current collectors 10, multiple second current collectors 11, multiple first insulating parts 3, and multiple second insulating parts 4.

[0018] (Exterior materials) The exterior material 9 is provided to protect the components located inside the battery cell 8. Specifically, multiple power generation elements 2, multiple first current collectors 10, multiple second current collectors 11, multiple first insulating parts 3, and multiple second insulating parts 4 are housed inside the exterior material 9. The exterior material 9 is made of, for example, an aluminum film.

[0019] (Current collector) Multiple first current collectors 10 and multiple second current collectors 11 are provided to electrically connect multiple power generation elements 2 to an external device. One of the first current collectors 10 and the second current collectors 11 is a positive electrode current collector, and the other is a negative electrode current collector. The first current collectors 10 and the second current collectors 11 are each in the form of a sheet. Multiple first current collectors 10 and multiple second current collectors 11 are arranged alternately in the stacking direction. Although not shown in the figures, multiple first current collectors 10 are bundled together at one end and connected to a tab that extends to the outside of the exterior material 9. Similarly, multiple second current collectors 11 are bundled together at one end and connected to a tab.

[0020] (Power generation element) Each power generation element 2 is the part that realizes the charge and discharge function. Each power generation element 2 is positioned between adjacent first current collectors 10 and second current collectors 11 in the stacking direction. Each power generation element 2 has a solid electrolyte layer 13, a first electrode layer 12, and a second electrode layer 14. The first electrode layer 12 is stacked on one surface of the solid electrolyte layer 13. The second electrode layer 14 is stacked on the other surface of the solid electrolyte layer 13. Each power generation element 2 is positioned between the first current collector 10 and the second current collector 11 such that the first electrode layer 12 is connected to the first current collector 10 and the second electrode layer 14 is connected to the second current collector 11.

[0021] The solid electrolyte layer 13 is a solid and can function as an electrolyte layer in a secondary battery; its material is not particularly limited. For example, the solid electrolyte layer 13 can be formed from sulfides or oxides. Preferably, the solid electrolyte layer 13 contains a sulfide solid electrolyte. Examples of sulfide solid electrolytes include LPS-based (e.g., argyrodite (Li6PS5Cl)) and LGPS-based (e.g., Li 10 GeP2S 12 Examples of materials include the following. The thickness of the solid electrolyte layer 13 is not particularly limited, but is, for example, 5 to 100 μm, preferably 20 to 60 μm.

[0022] The first electrode layer 12 and the second electrode layer 14 are layers that function as electrodes. One of the first electrode layer 12 and the second electrode layer 14 is a positive electrode layer, and the other is a negative electrode layer.

[0023] The positive electrode layer only needs to be made of a material that can release lithium ions during charging and absorb lithium ions during discharging. The positive electrode layer is made of a material that includes, for example, a resin binder and a positive electrode active material dispersed in the resin binder. As the positive electrode active material, for example, lithium metal composite oxides can be used. Examples of lithium metal composite oxides include layered rock salt type compounds such as LiCoO2, LiMnO2, LiNiO2, LiVO2, and Li(Ni-Mn-Co)O2, LiMn2O4, and LiNi 0.5 Mn 1.5 Examples include spinel-type compounds such as O4, olivine-type compounds such as LiFePO4 and LiMnPO4, and Si-containing compounds such as Li2FeSiO4 and Li2MnSiO4. Also, Li4Ti5O 12 Other options can also be used.

[0024] The thickness of the positive electrode layer is not particularly limited, but is, for example, 10 to 500 μm, preferably 50 to 200 μm.

[0025] The negative electrode layer should be configured to absorb (or deposit) lithium during charging and release lithium ions during discharge. For example, the negative electrode layer can be formed from a material comprising a resin binder and a negative electrode active material dispersed in the resin binder. Examples of negative electrode active materials include lithium metal, silicon materials, tin materials, compounds containing silicon or tin (oxides, nitrides, alloys with other metals), and carbon materials (graphite, etc.). The thickness of the negative electrode layer is, for example, 1 to 100 μm, preferably 5 to 80 μm.

[0026] In the power generation element 2 having the above-described configuration, during charging, lithium ions move from the positive electrode side to the negative electrode side via the solid electrolyte layer 13, and lithium is absorbed into the negative electrode layer. Alternatively, lithium is deposited on the negative electrode side. On the other hand, during discharge, lithium ions move from the negative electrode side to the positive electrode side via the solid electrolyte layer 13, and lithium is absorbed into the positive electrode layer. This enables the function of a secondary battery.

[0027] Furthermore, the power generation element 2 may function as a so-called "fully deposited" secondary battery. A fully deposited secondary battery is a battery configured such that, in a fully discharged state, the negative electrode side does not contain lithium as a negative electrode active material, and during charging, lithium ions move from the positive electrode side to the negative electrode side, and lithium metal is deposited on the negative electrode current collector. In such a battery, at least the lithium metal deposited on the negative electrode side during charging functions as a negative electrode layer, and is therefore included in the power generation element 2 in this embodiment.

[0028] Furthermore, in a fully deposited secondary battery, a negative electrode intermediate layer may be placed between the solid electrolyte layer 13 and the negative electrode current collector to prevent the deposited lithium metal from coming into contact with the solid electrolyte layer 13. The negative electrode intermediate layer is a layer provided between the deposited lithium metal and the solid electrolyte layer. The negative electrode intermediate layer contains a lithium-reactive material. Examples of lithium-reactive materials include materials that can intercept and deintercept lithium ions during charging, and metals that can alloy with lithium during charging.

[0029] While there are no particular limitations on the material capable of intercalating and deintercalating lithium ions, carbon materials are preferred. Specific examples of carbon materials include carbon black (specifically, acetylene black, Ketjenblack®, furnace black, channel black, thermal lamp black, etc.), carbon nanotubes (CNTs), graphite, and hard carbon. Among these, carbon black is preferred, and it is more preferable that it be at least one selected from the group consisting of acetylene black, Ketjenblack®, furnace black, channel black, and thermal lamp black.

[0030] Examples of metals that can be alloyed with lithium include In, Al, Si, Sn, Mg, Au, Ag, and Zn. Among these, In, Si, Sn, and Ag are preferred, with Ag being more preferred.

[0031] The lithium-reactive material may be used alone or in combination of two or more types. In the case of using two or more types in combination, it is preferable to use a material capable of intercalating and deintercalating lithium ions in combination with a metal that can alloy with lithium. This ensures sufficient strength and lithium-ion conductivity of the negative electrode intermediate layer. More specifically, it is preferable to use nanoparticles made of In, Si, Sn, and Ag in combination with carbon black, and more preferably to use nanoparticles made of Ag in combination with carbon black. When using a material capable of intercalating and deintercalating lithium ions in combination with a metal that can alloy with lithium, the mixing ratio (mass ratio) is not particularly limited, but the ratio of the material capable of intercalating and deintercalating lithium ions to the metal that can alloy with lithium is preferably 10:1 to 1:1, and more preferably 5:1 to 2:1.

[0032] The content of lithium-reactive material in the negative electrode intermediate layer (referring to the total content of two or more materials if they are used in combination; the same applies hereinafter) is not particularly limited, but is preferably in the range of 50 to 100% by mass, more preferably in the range of 70 to 100% by mass, even more preferably in the range of 85 to 99% by mass, and particularly preferably in the range of 90 to 100% by mass.

[0033] The negative electrode intermediate layer may consist solely of lithium-reactive material if a self-supporting film can be fabricated using only lithium-reactive material, but may also contain a binder as needed. The type of binder is not particularly limited, and any known binder in the art can be used as appropriate. Examples include polyvinylidene fluoride (PVDF) (including compounds in which hydrogen atoms are substituted with other halogen elements), polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), and carboxymethylcellulose.

[0034] The binder content in the negative electrode intermediate layer is not particularly limited, but is preferably in the range of 1 to 15% by mass, and more preferably in the range of 5 to 10% by mass. If the binder content is 1% by mass or more, a negative electrode intermediate layer with sufficient strength can be formed. If the binder content is 15% by mass or less, a negative electrode intermediate layer with sufficient lithium ion conductivity can be formed.

[0035] The thickness of the negative electrode intermediate layer is not particularly limited, but is preferably 1 to 50 μm, more preferably 5 to 40 μm, and even more preferably 10 to 30 μm. When the thickness of the negative electrode intermediate layer is 1 μm or more, the functions of the negative electrode intermediate layer can be fully exhibited. When the thickness of the negative electrode intermediate layer is 50 μm or less, the decrease in energy density can be suppressed.

[0036] Figure 3 shows a preferred example in which the edge of the solid electrolyte layer 13 is located outside the edges of the first electrode layer 12 and the second electrode layer 14 when viewed along the stacking direction. By adopting such a configuration, the growth of lithium dendrites that wrap around the edge of the solid electrolyte layer 13 is suppressed. Therefore, short circuits between the first electrode layer 12 and the second electrode layer 14 can be prevented.

[0037] Furthermore, when viewed along the stacking direction, the edges of the first electrode layer 12 and the edges of the second electrode layer 14 may or may not be aligned. In a preferred example, the edges of the negative electrode layer are located further out than the edges of the positive electrode layer. By adopting such a configuration, lithium is prevented from concentrating and depositing at the edges of the negative electrode layer during charging, thereby preventing a short circuit between the positive and negative electrodes.

[0038] (First insulating section and second insulating section) Next, the first insulating section 3 and the second insulating section 4 will be described. As previously stated, the first insulating section 3 and the second insulating section 4 are provided to apply sufficient pressure to the end of the power generation element 2.

[0039] Each first insulating section 3 is frame-shaped and is positioned to surround the outer edge of each power generation element 2. Similarly, each second insulating section 4 is frame-shaped and is positioned to surround the outer edge of each first insulating section 3. Each first insulating section 3 and each second insulating section 4 are positioned between adjacent first current collectors 10 and second current collectors 11 in the stacking direction, similar to each power generation element 2. That is, when viewed along the stacking direction, each first current collector 10 and each second current collector 11 are larger than each power generation element 2, and their outer edges are located outside the outer edges of each power generation element 2. On the outside of each power generation element 2, each first insulating section 3 and each second insulating section 4 are positioned between the first current collector 10 and the second current collector 11.

[0040] As previously described, the first insulating part 3 is insulating and composed of an elastic material. The first insulating part 3 is compressed. That is, the first insulating part 3 is pressurized and compressed along the lamination direction from the elastic sheet 7 via the current collectors (first current collector 10 and / or second current collector 11) and the outer covering material 9, etc. The inner circumferential end of the compressed first insulating part 3 is in contact with the outer circumferential end of the power generation element 2. Also, the outer circumferential end of the compressed first insulating part 3 is in contact with the inner circumferential end of the second insulating part 4.

[0041] The Young's modulus of the first insulating portion 3 is, for example, 1 MPa or less. The first insulating portion 3 can be formed from, for example, a rubber material.

[0042] The second insulating portion 4 is provided to restrict the compressed first insulating portion 3 from bulging outward. The second insulating portion 4 has a larger Young's modulus than the first insulating portion 3. The Young's modulus of the second insulating portion 4 is, for example, 1 MPa or more. The second insulating portion 4 can be formed from, for example, a rubber material. The outer peripheral end of the compressed first insulating portion 3 is in contact with the inner peripheral end of the second insulating portion 4. Because the Young's modulus of the second insulating portion 4 is larger than that of the first insulating portion 3, the first insulating portion 3 is prevented from bulging outward.

[0043] (Pressurization mechanism) Next, we will describe the elastic sheet 7 and the pressure plate 6, which function as the pressure mechanism 5.

[0044] As shown in Figure 3, the elastic sheet 7 is positioned on the outside of the exterior material 9 in the lamination direction. When viewed along the lamination direction, the outer edge of the elastic sheet 7 is located outside the second insulating portion 4. The pressure plate 6 is provided on the outside of the elastic sheet 7 in the lamination direction. When viewed along the lamination direction, the outer edge of the pressure plate 6 is located outside the elastic sheet 7. With this configuration, the power generation element 2, the first insulating portion 3, and the second insulating portion 4 are pressed along the lamination direction by the pressure plate 6 via the elastic sheet 7.

[0045] Furthermore, the power generation element 2 is typically harder (has a higher Young's modulus) than the first insulating part 3, which is an elastic material. Therefore, the elastic sheet 7 is compressed so that the portion overlapping the power generation element 2 is thinner than the portion overlapping the first insulating part 3.

[0046] As the elastic sheet 7, for example, a material with a Young's modulus of 10 MPa or less can be used. The Young's modulus of the elastic sheet 7 is preferably 0.1 to 10 MPa. As the elastic sheet 7, for example, a rubber sheet such as silicone rubber can be used. The thickness of the elastic sheet 7 is, for example, 0.3 to 3 mm, preferably 0.5 to 2 mm.

[0047] Next, the operation of the all-solid-state battery 1 according to this embodiment will be explained with reference to a reference example.

[0048] Figure 4A is a schematic cross-sectional view of an all-solid-state battery according to a reference example. This all-solid-state battery according to this reference example has the same configuration as the all-solid-state battery 1 according to this embodiment, except that it lacks the first insulating part 3 and the second insulating part 4. In Figure 4A, the pressure applied from the pressure plate 6 to the power generation element 2 is schematically shown by arrows. As shown in Figure 4A, in the all-solid-state battery according to the reference example, pressure is applied from the pressure plate 6 to the power generation element 2 via the elastic sheet 7, but this pressure tends to escape outward at the ends. In other words, it is difficult to apply force to the ends of the power generation element 2.

[0049] On the other hand, Figure 4B is a schematic diagram showing how pressure is applied in the all-solid-state battery 1 according to this embodiment. As shown in Figure 4B, in this embodiment, the power generation element 2 is pressurized along the stacking direction via the elastic sheet 7. The first insulating part 3 and the second insulating part 4 are also pressurized along the stacking direction. Since the first insulating part 3 is an elastic body, it is compressed by the pressurization. A force is generated in the compressed first insulating part 3 that tends to expand laterally. As a result, in addition to the force along the stacking direction from the elastic sheet 7, a lateral force from the first insulating part 3 is also applied to the end of the power generation element 2. In other words, the force applied to the first insulating part 3 along the stacking direction is converted into a lateral force. This makes it possible to apply sufficient pressure even to the end of the power generation element 2, which is difficult to pressurize. The outer peripheral end of the compressed first insulating part 3 is in contact with the inner peripheral end of the second insulating part 4. Since the Young's modulus of the second insulating part 4 is greater than that of the first insulating part 3, the outward displacement of the outer peripheral end of the first insulating part 3 is restricted. As a result, the force applied to the first insulating part 3 via the elastic sheet 7 is less likely to escape outwards and more likely to be directed towards the power generation element 2. From this viewpoint as well, the ends of the power generation element 2 are sufficiently pressurized. Therefore, it becomes possible to uniformly pressurize the entire surface of the all-solid-state battery 1.

[0050] The all-solid-state battery 1 according to this embodiment is used under pressurized conditions. Here, the outer peripheral end of the power generation element 2 and the inner peripheral end of the first insulating part 3 only need to be in contact under pressurized conditions. The first insulating part 3 and the second insulating part 4 also need to be in contact under pressurized conditions. In other words, if the system is not under pressurized conditions, the power generation element 2 and the first insulating part 3 may be arranged to be separated. Similarly, in the non-pressurized state, the first insulating part 3 and the second insulating part 4 may be separated. An example of the arrangement of the first insulating part 3 and the second insulating part 4 in the non-pressurized state will be described below.

[0051] Figure 5 is a diagram showing an example of the arrangement of the first insulating part 3 and the second insulating part 4, and is a schematic cross-sectional view showing the configuration of the all-solid-state battery 1 in a non-pressurized state. In the example shown in Figure 5, the first insulating part 3 is in contact with the power generation element 2 even in a non-pressurized state. On the other hand, in a non-pressurized state, the first insulating part 3 is separated from the second insulating part 4. According to this example, by arranging the first insulating part 3 so that it is in contact with the power generation element 2 even in a non-pressurized state, the ends of the power generation element 2 are more easily pressurized when pressurized.

[0052] Figure 6 shows another example of the arrangement of the first insulating part 3 and the second insulating part 4, and is a schematic cross-sectional view showing the configuration of the all-solid-state battery 1 in a non-pressurized state. In the example shown in Figure 6, in a non-pressurized state, the first insulating part 3 and the power generation element 2 are separated, and the first insulating part 3 and the second insulating part 4 are also separated. The structure of the power generation element 2 may change due to charging and discharging, etc. As shown in Figure 6, if the first insulating part 3 and the power generation element 2 are arranged to be separated in a non-pressurized state, the first insulating part 3 can more easily follow changes in the structure of the power generation element 2. Therefore, even if the structure of the power generation element 2 changes, it becomes easier to uniformly pressurize the ends of the power generation element 2.

[0053] Figure 7 shows yet another example of the arrangement of the first insulating part 3 and the second insulating part 4, and is a schematic cross-sectional view showing the configuration of the all-solid-state battery 1 in a non-pressurized state. In the example shown in Figure 7, the first insulating part 3 and the power generation element 2 are separated in the non-pressurized state. On the other hand, the first insulating part 3 and the second insulating part 4 are in contact even in the non-pressurized state. By adopting such a configuration, since the first insulating part 3 and the power generation element 2 are separated in the non-pressurized state, similar to the example shown in Figure 6, the first insulating part 3 can more easily follow structural changes in the power generation element 2, and it becomes easier to uniformly pressurize the ends of the power generation element 2. On the other hand, since the first insulating part 3 and the second insulating part 4 are in contact even in the non-pressurized state, the lateral force generated in the first insulating part 3 when pressurized is less likely to escape outwards. Therefore, the ends of the power generation element 2 can be pressurized more sufficiently.

[0054] Figure 8 shows yet another example of the arrangement of the first insulating part 3 and the second insulating part 4, and is a schematic cross-sectional view showing the configuration of the all-solid-state battery 1 in a non-pressurized state. In the example shown in Figure 8, the first insulating part 3 and the power generation element 2 are in contact in the non-pressurized state. The first insulating part 3 and the second insulating part 4 are also in contact even in the non-pressurized state. With this configuration, similar to the example shown in Figure 5, the first insulating part 3 is arranged to be in contact with the power generation element 2 in the non-pressurized state, so the end of the power generation element 2 is more easily pressurized when pressurized. In addition, similar to the example shown in Figure 7, since the first insulating part 3 and the second insulating part 4 are in contact even in the non-pressurized state, the force applied to the first insulating part 3 is more easily directed towards the power generation element 2 in the pressurized state. Therefore, the end of the power generation element 2 can be pressurized more sufficiently.

[0055] (Manufacturing method) Next, a method for manufacturing the all-solid-state battery 1 will be described. The method for manufacturing the all-solid-state battery 1 according to this embodiment is not particularly limited, as long as it is a method that allows the first insulating part 3 and the second insulating part 4 to be positioned so as to surround the end of the power generation element 2. An example of a manufacturing method is described below.

[0056] [Fabrication of the positive electrode layer] A slurry is prepared by weighing and mixing predetermined amounts of positive electrode active material, sulfide solid electrolyte, conductive additive, binder, and xylene. The obtained slurry is applied to both sides of a carbon-coated Al foil (positive electrode current collector) and dried to create a positive electrode layer with a thickness of 200 μm (100 μm on each side). In addition, rubber materials that will form the first insulating part 3 and the second insulating part 4 are bonded to predetermined positions on the positive electrode current collector.

[0057] [Preparation of a solid electrolyte layer] A slurry is prepared by mixing predetermined amounts of sulfide solid electrolyte, binder, and xylene. The prepared slurry is coated onto a SUS foil and dried to create a solid electrolyte layer with a thickness of 40 μm.

[0058] [Manufacturing of the negative electrode layer (or negative electrode intermediate layer)] A slurry is prepared by mixing predetermined amounts of negative electrode active material (or, if forming a negative electrode intermediate layer, silver particles and carbon particles), binder, and NMP (N-methylpyrrolidone). The prepared slurry is applied to both sides of the negative electrode current collector (SUS foil) and dried. This creates a negative electrode layer (or negative electrode intermediate layer) with a thickness of 20 μm (10 μm on each side). In addition, rubber materials that will form the first insulating part 3 and the second insulating part 4 are bonded to the negative electrode current collector.

[0059] [Fabrication of cathode / solid electrolyte layer laminates] A solid electrolyte layer is placed on the positive electrode layer, and the solid electrolyte layer is transferred onto the positive electrode layer by roll pressing. This results in a positive electrode current collector (positive electrode / solid electrolyte layer laminate) in which the positive electrode layer and the solid electrolyte layer are formed.

[0060] [Fabrication of electrode stacks] Next, a negative electrode current collector with a negative electrode layer (or negative electrode intermediate layer) formed on it and a positive electrode current collector with a positive electrode layer formed on it are stacked and roll-pressed to obtain an electrode stack. Note that multiple negative electrode current collectors and positive electrode current collectors are used as needed. Then, positive electrode tabs (aluminum tabs) are joined to the positive electrode current collector and negative electrode tabs (nickel tabs) are joined to the negative electrode current collector using an ultrasonic welding machine. After placing heat dissipation members on both sides of the electrode stack as needed, the electrode stack is housed in an outer material (aluminum laminate film) and vacuum-sealed. This gives rise to a battery cell 8. Then, a pair of elastic sheets 7 and a pair of pressure plates 6 are placed on it. Furthermore, the battery cell 8 is pressurized by binding the pair of pressure plates 6 together with rubber bands or the like. This gives rise to the all-solid-state battery 1 according to this embodiment.

[0061] In this embodiment, the case in which an elastic sheet 7 and a pressure plate 6 are used as the pressure mechanism 5 has been described. However, the pressure mechanism 5 only needs to be configured to apply pressure so as to compress the power generation element 2 and the first insulating part 3 in the stacking direction, and other configurations may be adopted. For example, it is not necessary for both the power generation element 2 and the first insulating part 3 to be pressurized by a single elastic sheet 7, and the member that pressurizes the first insulating part 3 and the member that pressurizes the power generation element 2 may be separate members.

[0062] Furthermore, in this embodiment, the case in which the all-solid-state battery 1 has multiple power generation elements 2 has been described. However, it is not necessary for multiple power generation elements 2 to be provided, and a single power generation element 2 may be used. In this case, the first current collector 10 and the second current collector 11 may each be single.

[0063] The first embodiment has been described above. Below, a representative summary of the relationship between the configuration and effects of the all-solid-state battery 1 according to this embodiment is provided.

[0064] The all-solid-state battery 1 according to this embodiment includes a power generation element 2 having a solid electrolyte layer 13, a first electrode layer 12 laminated on one surface of the solid electrolyte layer 13, and a second electrode layer 14 laminated on the other surface of the solid electrolyte layer 13; a frame-shaped first insulating part 3 formed of an elastic material and arranged to surround the outer peripheral end of the power generation element 2; a pressurizing mechanism 5 that pressurizes the power generation element 2 and the first insulating part 3 to compress them along the lamination direction; and a frame-shaped second insulating part 4 arranged to surround the outer peripheral end of the first insulating part 3. The Young's modulus of the second insulating part 4 is greater than that of the first insulating part 3. When pressurized by the pressurizing mechanism 5, the outer peripheral end of the first insulating part 3 is in contact with the second insulating part 4, and the outer peripheral end of the power generation element 2 is pressurized by the first insulating part 3. With this configuration, the end of the power generation element 2 is pressurized by the compressed first insulating part 3. In this case, the outer edge of the first insulating part 3 is in contact with the second insulating part 4, which has a higher Young's modulus than the first insulating part 3, thus restricting the outward displacement of the outer edge of the first insulating part 3. As a result, the lateral force generated in the compressed first insulating part 3 tends to be directed towards the power generation element 2. Consequently, the power generation element 2 is pressurized with a greater force, and the end of the power generation element 2 can be sufficiently pressurized.

[0065] In a preferred embodiment, the first insulating portion 3 and the second insulating portion 4 are configured such that the outer peripheral end of the first insulating portion 3 contacts the second insulating portion 4 when uncompressed. With this configuration, the lateral force generated in the compressed first insulating portion 3 is more easily directed toward the power generation element 2. Therefore, the end of the power generation element 2 can be pressurized more sufficiently.

[0066] In one preferred embodiment, the first insulating portion 3 is positioned away from the outer peripheral end of the power generation element 2 when it is not compressed. With this configuration, even if a structural change occurs in the power generation element 2, the first insulating portion 3 can easily follow the end of the power generation element 2. Therefore, even if the structure of the power generation element 2 changes, the end of the power generation element 2 can be uniformly pressurized.

[0067] In one preferred embodiment, the first insulating portion 3 is positioned to contact the outer peripheral end of the power generation element 2 when it is not compressed. With this configuration, the end of the power generation element 2 is more easily pressurized by the first insulating portion 3.

[0068] In a preferred embodiment, the all-solid-state battery 1 has a first current collector 10 and a second current collector 11 arranged to sandwich the power generation element 2 in the stacking direction. When viewed along the stacking direction, the outer peripheral ends of the first current collector 10 and the second current collector 11 are each located outside the outer peripheral end of the power generation element 2. The first insulating portion 3 and the second insulating portion 4 are arranged between the first current collector 10 and the second current collector 11. With this configuration, the ends of the power generation element 2 can be sufficiently pressurized by arranging the first insulating portion 3 and the second insulating portion 4 between the first current collector 10 and the second current collector 11.

[0069] (Second embodiment) Next, a second embodiment will be described. Figure 9 is a schematic cross-sectional view showing the configuration of the all-solid-state battery 1 according to the second embodiment, and is a diagram showing the state when no pressure is applied. In this embodiment, the frame widths of the first insulating part 3 and the second insulating part 4 have been modified. Detailed explanations of aspects that can be adopted in the same configuration as the previously described embodiment will be omitted.

[0070] Specifically, the frame width L1 of the first insulating section 3 is larger than the frame width L2 of the second insulating section 4. By adopting such a configuration, the size of the all-solid-state battery 1 can be reduced. That is, it is desirable that the first insulating section 3 has a certain width in order to generate sufficient pressing force in the lateral direction (towards the power generation element 2) when compressed along the stacking direction. On the other hand, the second insulating section 4 only needs to have the function of restricting the outward displacement of the compressed first insulating section 3, so it does not need to have the same width as the first insulating section 3. Therefore, the frame width L2 of the second insulating section 4 can be smaller than the frame width L1 of the first insulating section 3, thereby reducing the size of the all-solid-state battery 1.

[0071] (Third embodiment) Next, a third embodiment will be described. Figure 10 is a schematic cross-sectional view showing the configuration of the all-solid-state battery 1 according to the third embodiment, and is a diagram showing the state when no pressure is applied. In this embodiment, the configuration of the first insulating part 3 has been improved. Note that detailed explanations will be omitted for points where the same configuration as in the previously described embodiments can be adopted.

[0072] In this embodiment, the first insulating portion 3 is joined to the first current collector 10, but not to the second current collector 11. More specifically, the first insulating portion 3 is joined to both sides of the first current collector 10.

[0073] According to this embodiment, process costs can be reduced. Specifically, during manufacturing, the first insulating part 3 only needs to be joined to the first current collector 10. The process of joining the first insulating part 3 to the second current collector 11 is not necessary. Therefore, the manufacturing process can be shortened, and process costs can be reduced.

[0074] In the example shown in Figure 10, the first insulating part 3 and the second current collector 11 are separated. As shown in this figure, when not pressurized, the first insulating part 3 does not necessarily have to be in contact with the upper and lower current collectors; it is sufficient that it is configured so that a force is applied from the elastic sheet 7 side when pressurized.

[0075] In the example shown in Figure 10, there are irregularities on the end face of the power generation element 2, and the inner circumferential end of the first insulating part 3 fits into the recess of the power generation element 2. Specifically, on the end face of the power generation element 2, the end of the first electrode layer 12 is located inward from the end of the solid electrolyte layer 13. As a result, a recess is formed on the end face of the power generation element 2 with the end face of the first electrode layer 12 as its bottom surface. The first insulating part 3 is positioned so that its inner circumferential end fits into the recess of the power generation element 2. By adopting this configuration, it becomes possible to protect the end face of the first electrode layer 12 with the first insulating part 3.

[0076] (Fourth embodiment) Next, a fourth embodiment will be described. Figure 11 is a schematic cross-sectional view showing the configuration of the all-solid-state battery 1 according to the fourth embodiment, and is a diagram showing the state when no pressure is applied. In this embodiment, the configuration of the second insulating part 4 has been improved. For other points, the same configuration as in the third embodiment can be adopted.

[0077] Specifically, similar to the first insulating section 3, the second insulating section 4 is joined to the first current collector 10 but not to the second current collector 11. More specifically, the second insulating section 4 is joined to both sides of the first current collector 10.

[0078] According to this embodiment, process costs can be further reduced. Specifically, during manufacturing, the first insulating part 3 and the second insulating part 4 only need to be joined to the first current collector 10. There is no need to join the first insulating part 3 and the second insulating part 4 to the second current collector 11. Therefore, the manufacturing process can be shortened, and process costs can be further reduced.

[0079] Furthermore, according to this embodiment, the outward displacement of the first insulating portion 3 is more easily restricted by the second insulating portion 4. Therefore, the end of the power generation element 2 can be pressurized even more sufficiently.

[0080] (Fifth embodiment) Next, a fifth embodiment will be described. Figure 12 is a schematic cross-sectional view showing the configuration of the all-solid-state battery 1 according to the fifth embodiment, and is a diagram showing the state when no pressure is applied. In this embodiment, the configuration of the second insulating part 4 has been improved. For other points, the same configuration as in the third embodiment can be adopted.

[0081] In this embodiment, the first insulating portion 3 is joined to the first current collector 10 but not to the second current collector 11. On the other hand, the second insulating portion 4 is joined to the second current collector 11 but not to the first current collector 10. More specifically, the first insulating portion 3 is joined to both sides of the first current collector 10, and the second insulating portion 4 is joined to both sides of the second current collector 11.

[0082] According to this embodiment, during manufacturing, the first insulating part 3 only needs to be joined to the first current collector 10. The second insulating part 4 only needs to be joined to the second current collector 11. There is no need to join the second insulating part 4 to the first current collector 10, and there is no need to join the first insulating part 3 to the second current collector 11. Therefore, the manufacturing process can be shortened, and process costs can be further reduced.

[0083] In this embodiment as well, the displacement of the first insulating part 3 outward is restricted by the second insulating part 4, so that sufficient pressure can be applied to the end of the power generation element 2 from the first insulating part 3.

[0084] (Sixth embodiment) Next, a sixth embodiment will be described. Figure 13 is a schematic cross-sectional view showing the configuration of the all-solid-state battery 1 according to the sixth embodiment, and is a diagram showing the state when no pressure is applied. In this embodiment, the configuration of the first insulating part 3 has been improved. For other points, the same configuration as in the previously described embodiments can be adopted.

[0085] As shown in Figure 13, in this embodiment, the first insulating section 3 consists of two first insulating elements (3-1 and 3-2) arranged in the stacking direction. One of the first insulating elements 3-1 is joined to the first current collector 10. The other first insulating element 3-2 is joined to the second current collector 11. By adopting this configuration, the outward displacement of the first insulating section 3 is restricted by the second insulating section 4, and the force applied to the first insulating section 3 is directed towards the power generation element 2. Therefore, sufficient pressure can be applied to the end of the power generation element 2.

[0086] (Seventh Embodiment) Next, a seventh embodiment will be described. Figure 14 is a schematic cross-sectional view showing the configuration of the all-solid-state battery 1 according to the seventh embodiment, and is a diagram showing the state when no pressure is applied. In this embodiment, the configuration of the second insulating part 4 has been improved. For other points, the same configuration as in the previously described embodiments, particularly the sixth embodiment, can be adopted.

[0087] As shown in Figure 14, in this embodiment, the second insulating section 4 consists of two second insulating elements (4-1 and 4-2) arranged in the stacking direction. One of the second insulating elements 4-1 is joined to the first current collector 10. The other second insulating element 4-2 is joined to the second current collector 11. By adopting this configuration, the outward displacement of the first insulating section 3 is restricted by the second insulating section 4, and the force applied to the first insulating section 3 is directed towards the power generation element 2. Therefore, sufficient pressure can be applied to the end of the power generation element 2.

[0088] (Eighth embodiment) Next, an eighth embodiment will be described. Figure 15 is a schematic cross-sectional view showing the configuration of the all-solid-state battery 1 according to the eighth embodiment, and is a diagram showing the state when no pressure is applied. In this embodiment, the configuration of the first insulating part 3 and the second insulating part 4 has been improved. For other points, the same configuration as in the previously described embodiments can be adopted.

[0089] As shown in Figure 15, the length T2 of the second insulating portion 4 in the stacking direction is greater than the length T1 of the first insulating portion 3 in the stacking direction. With this configuration, the outward displacement of the first insulating portion 3 is more reliably restricted by the second insulating portion 4. Therefore, the force applied to the first insulating portion 3 is more easily directed toward the power generation element 2, and more sufficient pressure can be applied to the end of the power generation element 2.

[0090] The present invention has been described above using the first to eighth embodiments. These embodiments are not independent of each other and can be combined and used within a non-contradictory scope. [Explanation of symbols]

[0091] 1. All-solid-state battery, 2. Power generation element, 3. First insulating part, 4. Second insulating part, 5... Pressurizing mechanism, 6... Pressurizing plate, 7... Outer elastic member, 8... Battery cell, 9...Exterior material, 10...First current collector, 11...Second current collector, 12...first electrode layer, 13...solid electrolyte layer, 14...second electrode layer

Claims

1. A power generation element having a solid electrolyte layer, a first electrode layer laminated on one surface of the solid electrolyte layer, and a second electrode layer laminated on the other surface of the solid electrolyte layer, A frame-shaped first insulating portion, formed of an elastic material and arranged to surround the outer peripheral end of the power generation element, A pressurizing mechanism that applies pressure to compress the power generation element and the first insulating part along the stacking direction, A frame-shaped second insulating portion is arranged to surround the outer peripheral edge of the first insulating portion, Equipped with, The Young's modulus of the second insulating portion is greater than that of the first insulating portion. In the state pressurized by the pressurizing mechanism, the outer peripheral end of the first insulating part is in contact with the second insulating part, and the outer peripheral end of the power generation element is pressurized by the first insulating part. The first insulating portion is positioned so as to be separated from the outer peripheral end of the power generation element when it is not compressed. All-solid-state battery.

2. A power generation element having a solid electrolyte layer, a first electrode layer laminated on one surface of the solid electrolyte layer, and a second electrode layer laminated on the other surface of the solid electrolyte layer, A frame-shaped first insulating portion, formed of an elastic material and arranged to surround the outer peripheral end of the power generation element, A pressurizing mechanism that applies pressure to compress the power generation element and the first insulating part along the stacking direction, A frame-shaped second insulating portion is arranged to surround the outer peripheral edge of the first insulating portion, Equipped with, The Young's modulus of the second insulating portion is greater than that of the first insulating portion. In the state pressurized by the pressurizing mechanism, the outer peripheral end of the first insulating part is in contact with the second insulating part, and the outer peripheral end of the power generation element is pressurized by the first insulating part. Furthermore, The power generation element has a first current collector and a second current collector that are provided so as to sandwich it in the stacking direction, When viewed along the stacking direction, the outer peripheral end of the first current collector and the outer peripheral end of the second current collector are each located outside the outer peripheral end of the power generation element. The first insulating portion and the second insulating portion are arranged between the first current collector and the second current collector. The first insulating portion is joined to the first current collector, but not to the second current collector. All-solid-state battery.

3. A solid-state battery according to claim 1 or 2, The first insulating portion and the second insulating portion are configured such that, when not compressed, the outer peripheral end of the first insulating portion contacts the second insulating portion. All-solid-state battery.

4. A solid-state battery as described in claim 2, The first insulating portion is positioned so as to be away from the outer edge of the power generation element when it is not compressed. All-solid-state battery.

5. A solid-state battery as described in claim 2, The first insulating portion is arranged to contact the outer peripheral end of the power generation element when it is not compressed. All-solid-state battery.

6. A solid-state battery according to claim 1 or 2, The frame width of the first insulating part is greater than the frame width of the second insulating part. All-solid-state battery.

7. A solid-state battery as described in claim 1, Furthermore, The power generation element has a first current collector and a second current collector that are provided so as to sandwich it in the stacking direction, When viewed along the stacking direction, the outer peripheral end of the first current collector and the outer peripheral end of the second current collector are each located outside the outer peripheral end of the power generation element. The first insulating portion and the second insulating portion are arranged between the first current collector and the second current collector. All-solid-state battery.

8. A solid-state battery as described in claim 7, The first insulating portion is joined to the first current collector, but not to the second current collector. All-solid-state battery.

9. A solid-state battery according to claim 2 or 8, The second insulating portion is joined to the first current collector, but not to the second current collector. All-solid-state battery.

10. A solid-state battery according to claim 2 or 8, The second insulating portion is joined to the second current collector, but not to the first current collector. All-solid-state battery.

11. A solid-state battery according to claim 1 or 2, The first insulating portion consists of two first insulating elements arranged in the stacking direction. All-solid-state battery.

12. A solid-state battery according to claim 1 or 2, The second insulating portion consists of two second insulating elements arranged in the stacking direction. All-solid-state battery.

13. A solid-state battery according to claim 1 or 2, The length of the second insulating portion in the stacking direction is greater than the length of the first insulating portion in the stacking direction. All-solid-state battery.

14. The steps of providing an all-solid-state battery as described in claim 1 or 2, A step of applying pressure to compress the all-solid-state battery in the stacking direction, Equipped with, The aforementioned pressurizing step is, The steps include compressing the first insulating portion in the stacking direction to pressurize the end of the power generation element through the first insulating portion, The second insulating portion restricts the outer peripheral end of the compressed first insulating portion from being displaced outward, Equipped with, A method for pressurizing all-solid-state batteries.

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