All-solid-state battery

Abstract

This all-solid-state battery comprises: a container; an electrode laminate that is housed in the container; and a tracer substance-containing member that is housed in the container and contains a tracer substance.

Description

All solid state battery

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

[0002] An all-solid-state battery is a secondary battery that uses a solid electrolyte. An all-solid-state battery may be provided as a cell. The cell includes a container and an electrode stack housed in the container. The container is required to be free of defects. Therefore, the container is inspected for defects as needed.

[0003] As a technology for inspecting defects in a container, Patent Document 1 (JP 2022-95089 A) discloses an all-solid-state lithium-ion battery that includes a solid-state battery having a specific configuration and an exterior film that houses the solid-state battery, and in which a specific inspection recess or inspection protrusion is formed on the surface of the exterior film.

[0004] It would be useful to provide a new technique that can inspect defects in containers of all-solid-state batteries. Therefore, an object of the present invention is to provide a new technique that can inspect defects in containers of all-solid-state batteries.

[0005] FIG. 1 is a schematic cross-sectional view showing an all-solid-state battery according to an embodiment. FIG. 2 is a schematic cross-sectional view showing an all-solid-state battery according to a modified example of Aspect 1. FIG. 3A is a plan view showing an example of the shape of a tracer substance-containing member. FIG. 3B is a plan view showing an example of the shape of a tracer substance-containing member. FIG. 3C is a plan view showing an example of the shape of a tracer substance-containing member. FIG. 3D is a plan view showing an example of the shape of a tracer substance-containing member. FIG. 4A is a schematic cross-sectional view showing an example of Aspect 2. FIG. 4B is a plan view showing a tracer substance-containing member 8 of Aspect 2. FIG. 5A is a schematic cross-sectional view showing a modified example of Aspect 2. FIG. 5B is a view showing another modified example of Aspect 2. FIG. 6A is a plan view showing another example of a tracer substance-containing member. FIG. 6B is a plan view showing another example of a tracer substance-containing member.

[0006] In this specification, the term "all-solid-state battery" refers to a secondary battery in which the electrolyte layer, the positive electrode layer, and the negative electrode layer are all substantially solid. Each layer may be "substantially" solid, and a small amount of liquid material may be used.

[0007] Hereinafter, an all-solid-state battery according to an embodiment of the present invention will be described with reference to the drawings.

[0008] 1 is a schematic cross-sectional view showing an all-solid-state battery 1 according to this embodiment. The all-solid-state battery 1 includes a container 9, an electrode stack 2, and a tracer substance-containing member 8. The electrode stack 2 and the tracer substance-containing member 8 are housed in the container 9. The tracer substance-containing member 8 contains a tracer substance.

[0009] In this embodiment, the presence or absence of defects in the container 9 is inspected by detecting the tracer material. For example, during inspection, the all-solid-state battery 1 is placed in a chamber. Then, the gas in the chamber is sent to a device for detecting the tracer material, and the presence or absence of the tracer material is inspected. If a defect exists in the container 9, the tracer material leaks to the outside of the container 9 through the defect, and the tracer material is detected. Therefore, by checking the presence or absence of the tracer material, the presence or absence of defects in the container 9 can be known.

[0010] In a lithium-ion battery that uses an electrolyte, rather than an all-solid-state battery, if there is a defect in the container, the volatilized electrolyte will leak through the defect. Therefore, defects can be inspected by checking whether or not components contained in the electrolyte have leaked. On the other hand, in an all-solid-state battery, the electrolyte is solid, so even if the presence or absence of leaked substances is checked, it is not possible to determine whether or not there is a defect. However, according to this embodiment, since a tracer substance is contained in the container 9, it is possible to inspect for defects by detecting leaked substances, even though the battery is an all-solid-state battery.

[0011] The above is an outline of this embodiment. The configuration of each part of this embodiment will now be described in detail.

[0012] (Electrode Stack) The electrode stack 2 has a solid electrolyte layer 5, an anode layer 6, a cathode layer 7, a cathode current collector 3, and an anode current collector 4. These are stacked in the stacking direction. Specifically, the anode layer 6 and the cathode layer 7 are arranged to sandwich the solid electrolyte layer 5 in the stacking direction. The anode current collector 4 is arranged on the anode layer 6, and the cathode current collector 3 is arranged on the cathode layer 7. The solid electrolyte layer 5, the anode layer 6, and the positive electrode layer 7 overlap in the charge / discharge region 10. Meanwhile, the positive electrode current collector 3 and the anode current collector 4 extend laterally from the charge / discharge region 10.

[0013] 1 , the detailed configuration is omitted, but the positive electrode current collector 3 and the negative electrode current collector 4 are each connected to a tab inside the container 9. One end of the tab is disposed inside the container 9, and the other end is disposed outside the container 9. In other words, the tab extends so as to penetrate through the container 9. This makes it possible to electrically connect the electrode stack 2 to an external device via the tab and each current collector.

[0014] 1, a stack of a plurality of units, each of which is made up of a solid electrolyte layer 5, an anode layer 6, and a cathode layer 7, is stacked with a current collector (a cathode current collector 3 in FIG. 1) sandwiched therebetween. As in the example shown in FIG. 1, the electrode stack 2 may include a plurality of units.

[0015] (Container) The material of the container 9 is not particularly limited. For example, the container 9 is formed of a pair of laminate films. That is, the all-solid-state battery 1 may be a so-called laminate-type all-solid-state battery cell. The pair of laminate films are arranged to sandwich the electrode stack 2 in the stacking direction. The pair of laminate films are bonded at their outer peripheries by thermal welding or the like.

[0016] The inside of the container 9 is decompressed. The internal space of the container 9 is sealed. In Fig. 1, for ease of viewing, a space is depicted between the side surface of the electrode stack 2 and the container 9, but in reality, the two are in almost tight contact with each other.

[0017] (Tracer Substance-Containing Member) As described above, the tracer substance-containing member 8 contains a tracer substance.

[0018] The form of the tracer material is not particularly limited, but is preferably a gas. Gas has higher fluidity than solid or liquid. If the tracer material is a gas, the tracer material is more likely to leak if there is a defect in the container 9. Therefore, it is possible to inspect for defects in a short time.

[0019] The tracer material is preferably a gas with low reactivity. Examples of such gases include noble gases, nitrogen, and carbon dioxide. Preferably, the tracer material is a noble gas. Examples of noble gases include helium, neon, and argon.

[0020] More preferably, the tracer material is helium. Helium has a small molecular size. Therefore, even if the size of a defect generated in the container 9 is small, helium can easily leak through the defect to the outside. Therefore, if helium is used, even small defects can be easily detected.

[0021] The tracer substance-containing member 8 may be any member capable of retaining a tracer substance. For example, a porous body may be used as the tracer substance-containing member 8. The use of a porous body allows the tracer substance to be stored in its pores. Examples of porous bodies include metal porous bodies, porous glass, plastic porous bodies, porous carbon materials, and ceramic materials. Examples of metal porous bodies include those made of iron, titanium, copper, nickel, and alloys thereof. Examples of plastic porous bodies include porous bodies made of polyethylene, polystyrene, and polypropylene. Examples of porous carbon materials include activated carbon and carbon nanotubes. Examples of ceramic materials include silica, alumina, zirconia, zeolite, and composite oxides thereof.

[0022] In a preferred embodiment, the tracer substance-containing member 8 is made of a ceramic material. Ceramic materials are thermally and chemically stable materials. This improves the durability of the tracer substance-containing member 8. Furthermore, ceramic materials are insulating materials. This allows the tracer substance-containing member 8 to function as an insulating member to prevent short circuits.

[0023] Preferably, the tracer material containing member 8 has a thickness of 0.1 cm ３ / g or more. If the tracer substance-containing member 8 has such a pore volume, a sufficient amount of the tracer substance can be contained in the tracer substance-containing member 8. In a preferred embodiment, the volume of the container 9 is 30 to 200 cm ３ and the tracer substance-containing member 8 is 0.1 cm ３ In another preferred embodiment, the tracer substance-containing member 8 is made of a ceramic material and has a pore volume of 0.1 cm 3 / g or more. ３ The pore volume of the tracer substance-containing member 8 is N ２ It can be determined by gas adsorption method.

[0024] The amount of the tracer substance-containing member 8 contained in the container 9 is preferably 1 g or more. If the tracer substance-containing member 8 is contained in such an amount, a sufficient amount of tracer substance for detecting defects can be contained in the container 9. In one preferred embodiment, the volume of the container 9 is 30 to 200 cm ３ and 1 g or more of the tracer substance-containing member 8 is contained in the container 9.

[0025] The amount of the tracer substance contained in the tracer substance-containing member 8 is preferably 0.05 μg or more. If the tracer substance is contained in such an amount, the tracer substance will be easily detected when a defect exists. In a preferred embodiment, the volume of the container 9 is 30 to 200 cm ３ and the tracer substance-containing member 8 contains 0.05 μg or more of the tracer substance.

[0026] The method for containing the tracer substance in the tracer substance-containing member 8 is not particularly limited. For example, if the tracer substance is a gas, the tracer substance can be retained (contained) in the tracer substance-containing member by creating an atmosphere containing the tracer substance when the electrode laminate 2 is housed in the container 9. For example, when manufacturing the all-solid-state battery 1, a pair of laminate films is prepared as the container 9, and the electrode laminate 2 and the tracer substance-containing member 8 are placed between the pair of laminate films. Then, the space formed between the pair of laminate films is evacuated (depressurized), and the outer peripheries of the pair of laminate films are joined by thermal welding or the like. This results in a configuration in which the electrode laminate 2 and the tracer substance-containing member 8 are housed in the container 9. In this case, if the environment before depressurization is a tracer substance atmosphere, most of the tracer substance is exhausted during depressurization, but at least a sufficient amount of the tracer substance for detection is taken in and remains in the tracer substance-containing member 8. Therefore, the tracer substance-containing member 8 that retains the tracer substance can be housed in the container 9.

[0027] Alternatively, the tracer substance may be sprayed between a pair of laminate films using a nozzle or the like when the laminate films are bonded. This method also allows the tracer substance to be contained in the tracer substance-containing member 8. Note that the time of bonding the laminate films refers to, for example, the period from when the electrode stack and the tracer substance-containing member are placed between a pair of laminate films until just before bonding (sealing) the fourth edge of the periphery (the edge or portion to be bonded last) while reducing the pressure. It is also possible to spray the tracer substance when bonding under reduced pressure, but spraying the tracer substance when bonding the laminate films described above allows the gas (air) in the space within the laminate films to be replaced with more tracer substance.

[0028] There are no particular limitations on the shape and arrangement of the tracer substance-containing member 8. The shape, arrangement, etc. of the tracer substance-containing member 8 will be described below with reference to specific examples.

[0029] (Aspect 1) The tracer substance-containing member according to aspect 1 is in the form of a sheet, as shown in Fig. 1 . Furthermore, the tracer substance-containing member 8 is disposed on the electrode stack 2. With this configuration, during production, the tracer substance-containing member 8 can be disposed at a desired position simply by placing the tracer substance-containing member 8 on the electrode stack 2. The additional steps and equipment required for disposing the tracer substance-containing member 8 can be minimized.

[0030] The tracer substance-containing member 8 does not contribute to charging and discharging. Therefore, it is preferable that the volume occupied by the tracer substance-containing member 8 is small. If the tracer substance-containing member 8 is in a sheet shape, the volume occupied by the tracer substance-containing member 8 can be minimized by using a thin sheet.

[0031] The tracer substance-containing member 8 may be a free-standing film, or may be supported on a support (e.g., a plastic film).

[0032] In the example shown in Fig. 1, one tracer substance-containing member 8 is accommodated in the container 9. However, a plurality of tracer substance-containing members 8 may be contained in the container 9. Fig. 2 is a schematic cross-sectional view showing an all-solid-state battery according to a modified example of embodiment 1. In the modified example shown in Fig. 2, two tracer substance-containing members are contained. The two tracer substance-containing members are arranged at positions that sandwich the electrode stack 2 in the stacking direction.

[0033] The shape of the tracer substance-containing member 8 when viewed along the stacking direction is not particularly limited. FIGS. 3A to 3D are plan views showing examples of the shape of the tracer substance-containing member 8. In the example shown in FIG. 3A , when viewed along the stacking direction, the outer peripheral edge of the tracer substance-containing member 8 coincides with the outer peripheral edge of the charge / discharge region 10 (the region where the solid electrolyte layer 5, the positive electrode layer 7, and the negative electrode layer 6 overlap). On the other hand, in the example shown in FIG. 3B , when viewed along the stacking direction, the outer peripheral edge of the tracer substance-containing member 8 is located inside the outer peripheral edge of the charge / discharge region 10. In the example shown in FIG. 3C , the tracer substance-containing member 8 is frame-shaped. The outer peripheral edge of the tracer substance-containing member 8 coincides with the outer peripheral edge of the charge / discharge region 10. In the example shown in FIG. 3D , when viewed along the stacking direction, the charge / discharge region 10 is rectangular. The tracer substance-containing member 8 is arranged to correspond to three sides of the outer periphery of the charge / discharge region 10.

[0034] 3A, 3C, and 3D, the tracer substance-containing member 8 is located near the outer periphery of the container 9. Defects are likely to occur in the container 9 at positions corresponding to the corners of the electrode stack 2, i.e., the outer periphery of the container 9. If the tracer substance-containing member 8 is located near the outer periphery of the container 9, the tracer substance is more likely to leak to the outside if a defect exists. This makes it possible to more reliably detect defects.

[0035] (Aspect 2) On the other hand, the tracer substance-containing member 8 does not necessarily have to be in a sheet form. Also, it does not necessarily have to be laminated on the electrode laminate 2. Hereinafter, another aspect regarding the shape and arrangement of the tracer substance-containing member 8 will be described as aspect 2.

[0036] Fig. 4A is a schematic cross-sectional view showing an example of Aspect 2. Fig. 4B is a plan view showing a tracer substance-containing member 8. As shown in Fig. 4A and Fig. 4B, the tracer substance-containing member 8 is frame-shaped and is provided at a position so as to surround the solid electrolyte layer 5, the positive electrode layer 7, and the negative electrode layer 6 in the planar direction (the direction perpendicular to the stacking direction).

[0037] According to this aspect, it is possible to more efficiently detect defects in the container 9. As described above, the location where defects are likely to occur in the container 9 is the outer periphery. According to this aspect, since the tracer substance-containing member 8 is present near the location where defects are likely to occur, it is possible to more reliably detect defects.

[0038] In this embodiment, the tracer substance-containing member 8 is preferably an insulating member (e.g., a ceramic material). If the tracer substance-containing member 8 is an insulating member, it is possible to suppress the formation of lithium dendrites at the end of the electrode stack 2. As a result, it is possible to impart a short-circuit prevention function to the tracer substance-containing member 8.

[0039] In this embodiment, the tracer substance-containing member 8 does not necessarily have to be disposed so as to surround all of the solid electrolyte layer 5, the positive electrode layer 7, and the negative electrode layer 6. The tracer substance-containing member 8 only needs to be disposed so as to surround at least one of the solid electrolyte layer 5, the positive electrode layer 7, and the negative electrode layer 6. This point will be described with reference to FIGS. 5A and 5B .

[0040] 5A is a schematic cross-sectional view showing a modified example of Aspect 2. In the example shown in Fig. 5A, the tracer substance-containing member 8 is disposed in a position surrounding only the positive electrode layer 7 among the solid electrolyte layer 5, the positive electrode layer 7, and the negative electrode layer 6. Specifically, the outer peripheral edge of the positive electrode layer 7 is positioned slightly inward relative to the outer peripheral edges of the solid electrolyte layer 5 and the negative electrode layer 6. The outer peripheral edge of the tracer substance-containing member 8 is aligned with the outer peripheral edges of the solid electrolyte layer 5 and the negative electrode layer 6.

[0041] 5B is a diagram showing another modified example. In the example shown in FIG. 5B, the tracer substance-containing member 8 is disposed in a position so as to surround only the anode layer 6 among the solid electrolyte layer 5, the cathode layer 7, and the anode layer 6. Specifically, the outer peripheral edge of the anode layer 6 is positioned slightly inward from the outer peripheral edges of the solid electrolyte layer 5 and the cathode layer 7. The outer peripheral edge of the tracer substance-containing member 8 is aligned with the outer peripheral edges of the solid electrolyte layer 5 and the cathode layer 7.

[0042] 5A and 5B can also achieve the same effects as the example shown in Figures 4A and 4B. That is, if the tracer substance-containing member 8 is arranged along an area surrounding at least one of the solid electrolyte layer 5, the positive electrode layer 7, and the negative electrode layer 6, the tracer substance-containing member will be present near an area where defects are likely to occur, and defects in the container 9 can be efficiently detected. Furthermore, if an insulating material is used as the tracer substance-containing member 8, the generation of lithium dendrites at the end of the electrode stack 2 can be suppressed.

[0043] In the example shown in FIG. 5A , the outer peripheral edge of the tracer substance-containing member 8 is aligned with the outer peripheral edges of the solid electrolyte layer 5 and the negative electrode layer 6. Similarly, in the example shown in FIG. 5B , the outer peripheral edge of the tracer substance-containing member 8 is aligned with the outer peripheral edges of the solid electrolyte layer 5 and the positive electrode layer 7. However, these outer peripheral edges do not necessarily need to be aligned, and their positional relationship is not limited. For example, from the viewpoint of suppressing lithium dendrites, the outer peripheral edge of the positive electrode layer 7 may be located outside the outer peripheral edge of the negative electrode layer. Furthermore, from the viewpoint of suppressing damage to the solid electrolyte layer when pressure is applied, the outer peripheral edge of the tracer substance-containing member 8 may be located outside the outer peripheral edge of the solid electrolyte layer 5. On the other hand, the outer peripheral edge of the tracer substance-containing member 8 may be located inside the outer peripheral edge of the solid electrolyte layer 5.

[0044] In this embodiment, the tracer substance-containing member 8 does not necessarily have to be provided so as to surround the entire periphery of the solid electrolyte layer 5, the positive electrode layer 7, or the negative electrode layer 6. The tracer substance-containing member 8 may be provided in at least a part of the region surrounding the solid electrolyte layer 5, the positive electrode layer 7, or the negative electrode layer 6. This point will be described with reference to FIGS. 6A and 6B.

[0045] 6A is a plan view showing another example of the tracer substance-containing member 8. In the example shown in Fig. 6A, the solid electrolyte layer 5, the positive electrode layer 7, and the negative electrode layer 6 are rectangular. The tracer substance-containing member 8 is arranged along three sides of the solid electrolyte layer 5, the positive electrode layer 7, and the negative electrode layer 6.

[0046] 6B is a plan view showing yet another example of the tracer substance-containing member 8. In the example shown in Fig. 6B, the solid electrolyte layer 5, the positive electrode layer 7, and the negative electrode layer 6 are rectangular, as in the example shown in Fig. 6A. However, the tracer substance-containing member 8 is arranged along two opposing sides of the solid electrolyte layer 5, the positive electrode layer 7, and the negative electrode layer 6.

[0047] As described above, the tracer substance-containing member 8 may be provided in at least a part of the region surrounding the solid electrolyte layer 5, the positive electrode layer 7, or the negative electrode layer 6. Even when such a configuration is adopted, the tracer substance-containing member 8 is disposed near the outer periphery of the container 9 where defects are likely to occur, making it easier to detect defects. Furthermore, if an insulating member is used as the tracer substance-containing member 8, it is possible to suppress the generation of lithium dendrites at least in the portion where the tracer substance-containing member 8 is provided, thereby achieving a certain effect in preventing short circuits.

[0048] [Supplementary Note] The present invention has been described above with reference to the embodiments. The main configurations and effects of the present invention will be summarized below as supplementary notes.

[0049] (Supplementary Note 1) An all-solid-state battery comprising: a container 9; an electrode stack 2 housed in the container; and a tracer substance-containing member 8 housed in the container and containing a tracer substance.

[0050] According to this configuration, if there is a defect in the container, the tracer material will leak out of the container, and therefore, by checking for the presence or absence of the leaked tracer material, it is possible to check for the presence or absence of the defect.

[0051] (Supplementary Note 2) The all-solid-state battery according to Supplementary Note 1, wherein the tracer substance is a gas.

[0052] This configuration allows the tracer material to leak more easily when a defect exists, making it easier to detect the defect.

[0053] (Supplementary Note 3) The all-solid-state battery according to Supplementary Note 2, wherein the tracer material is helium gas.

[0054] Helium gas has a small molecular size, so if a defect exists, the tracer substance will leak out easily, making it easier to detect the defect.

[0055] (Supplementary Note 4) The all-solid-state battery according to any one of Supplementary Notes 1 to 3, wherein the tracer substance-containing member 8 includes a porous material.

[0056] According to this configuration, the tracer substance can be stored in the pores of the tracer substance-containing member, so that a sufficient amount of the tracer substance can be contained.

[0057] (Supplementary Note 5) The all-solid-state battery according to any one of Supplementary Notes 1 to 4, wherein the tracer substance-containing member 8 contains a ceramic material.

[0058] According to this configuration, since the ceramic material is a thermally and chemically stable material, the durability of the tracer substance-containing member 8 is improved. In addition, since the ceramic material is an insulating material, it is possible to impart a function for preventing short circuits to the tracer substance-containing member 8.

[0059] (Supplementary Note 6) The all-solid-state battery according to any one of Supplementary Notes 1 to 5, wherein the tracer substance-containing member 8 is sheet-shaped and is disposed on the electrode laminate 2.

[0060] This configuration allows the tracer substance-containing member to be easily placed on the electrode stack, minimizing the need for additional equipment and processes. Furthermore, if the tracer substance-containing member is thin, the volume occupied by members that do not contribute to charging and discharging can be reduced.

[0061] (Appendix 7) The all-solid-state battery according to any one of Appendices 1 to 6, wherein the electrode stack 2 has a solid electrolyte layer 5, and a positive electrode layer 7 and a negative electrode layer 6 arranged to sandwich the solid electrolyte layer in the stacking direction, and the tracer substance-containing member 8 is arranged in at least a part of an area surrounding the solid electrolyte layer, the positive electrode layer, or the negative electrode layer.

[0062] With this configuration, the tracer substance-containing member is located near the outer periphery of the container, where defects are more likely to occur. Therefore, if a defect exists, the tracer substance is more likely to leak. This makes it easier to detect defects.

[0063] (Supplementary Note 8) The all-solid-state battery according to Supplementary Note 7, wherein the tracer substance-containing member is insulating.

[0064] According to this configuration, the tracer substance-containing member 8 can suppress the formation of lithium dendrites at the ends of the electrode stack 2, thereby preventing short circuits.

Claims

1. An all-solid-state battery comprising: a container; an electrode stack housed in the container; and a tracer substance-containing member housed in the container and containing a tracer substance.

2. An all-solid-state battery according to claim 1, wherein the tracer substance is a gas.

3. An all-solid-state battery according to claim 2, wherein the tracer substance is helium gas.

4. An all-solid-state battery according to claim 1 or 2, wherein the tracer substance-containing member includes a porous material.

5. An all-solid-state battery according to claim 1 or 2, wherein the tracer substance-containing member contains a ceramic material.

6. An all-solid-state battery according to claim 1 or 2, wherein the tracer substance-containing member is in the form of a sheet and is disposed on the electrode laminate.

7. An all-solid-state battery according to claim 1 or 2, wherein the electrode stack has a solid electrolyte layer, and a positive electrode layer and a negative electrode layer arranged to sandwich the solid electrolyte layer in the stacking direction, and the tracer substance-containing member is arranged in at least a part of an area surrounding the solid electrolyte layer, the positive electrode layer, or the negative electrode layer.

8. An all-solid-state battery according to claim 7, wherein the tracer substance-containing member is insulating.

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