All-solid-state battery

Abstract

Provided is an all-solid-state battery having: a solid electrolyte layer; a positive electrode layer and a negative electrode intermediate layer provided so as to sandwich the solid electrolyte layer; and a negative electrode current collector foil provided on the negative electrode intermediate layer. In the all-solid-state battery, the solid electrolyte layer and the negative electrode current collector foil have outer shapes larger than the negative electrode intermediate layer. The negative electrode current collector foil is configured to cover the negative electrode intermediate layer, and at least a part of the outer peripheral edge thereof not in contact with the negative electrode intermediate layer is in contact with the outer peripheral edge of the solid electrolyte layer.

Description

all solid state battery

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

[0002] JP2022-98487A discloses an all-solid-state battery that uses a layer (negative electrode intermediate layer) made of a metal and a carbonaceous material (carbon) as the negative electrode layer. It is known that the use of a negative electrode intermediate layer, such as the all-solid-state battery described in JP2022-98487A, enables charging and discharging without cell short circuit.

[0003] However, in metal deposition-type all-solid-state batteries in which alkali metals such as lithium metal (Li) are deposited on the negative electrode side during charging, even when a negative electrode intermediate layer is used, alkali metals can deposit and grow on the edge (side) of the negative electrode intermediate layer during charging. Because the outside of the edge of the negative electrode intermediate layer is a non-pressurized portion of the all-solid-state battery, the alkali metal deposited on the edge of the negative electrode intermediate layer during charging does not return to the positive electrode during discharge and becomes alkali metal that does not contribute to the charge / discharge reaction. This can result in a decrease in charge / discharge capacity. Furthermore, if the deposited alkali metal reaches the positive electrode layer or the positive electrode current collector foil, it can lead to a cell short circuit.

[0004] The present invention has been made in view of the above problems, and has an object to provide an all-solid-state battery that suppresses a decrease in charge / discharge capacity and cell short-circuiting.

[0005] According to one aspect of the present invention, there is provided an all-solid-state battery including a solid electrolyte layer, a positive electrode layer and a negative electrode intermediate layer disposed so as to sandwich the solid electrolyte layer, and a negative electrode current collector foil disposed on the negative electrode intermediate layer. In this all-solid-state battery, the solid electrolyte layer and the negative electrode current collector foil have outer dimensions larger than those of the negative electrode intermediate layer, and the negative electrode current collector foil is configured to cover the negative electrode intermediate layer, with at least a portion of the outer edge that is not in contact with the negative electrode intermediate layer in contact with the outer edge of the solid electrolyte layer.

[0006] Fig. 1 is a schematic diagram showing the main configuration of an all-solid-state battery according to one embodiment of the present invention. Fig. 2 is a schematic diagram of an all-solid-state battery according to a conventional example. Fig. 3 is a schematic diagram of an all-solid-state battery according to a modified example. Fig. 4 is a schematic diagram of an all-solid-state battery according to a modified example.

[0007] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0008] [Embodiment] FIG. 1 is a schematic diagram showing the main components of an all-solid-state battery 1 according to one embodiment of the present invention. The all-solid-state battery 1 is a metal deposition-type battery in which an alkali metal is deposited on a negative electrode current collector foil during charging. In this embodiment, the all-solid-state battery 1 is a lithium deposition-type battery in which lithium metal (Li) is deposited in particular, and is a secondary battery in which charging and discharging are performed by the movement of lithium ions between the positive electrode and the negative electrode. The all-solid-state battery 1 includes a solid electrolyte layer 2, a positive electrode layer 3, a negative electrode intermediate layer 4, a positive electrode current collector foil 5, and a negative electrode current collector foil 6. The positive electrode layer 3 and the negative electrode intermediate layer 4 are disposed so as to sandwich the solid electrolyte layer 2. The positive electrode current collector foil 5 is disposed on the positive electrode layer 3, and the negative electrode current collector foil 6 is disposed on the negative electrode intermediate layer 4 (below the negative electrode intermediate layer 4 in the drawing). That is, in the all-solid-state battery 1, the negative electrode current collector foil 6, the negative electrode intermediate layer 4, the solid electrolyte layer 2, the positive electrode layer 3, and the positive electrode current collector foil 5 are laminated in this order.

[0009] The overall shape of the all-solid-state battery 1 is not particularly limited, but may be, for example, a sheet shape. That is, the solid electrolyte layer 2, the positive electrode layer 3, the negative electrode intermediate layer 4, the positive electrode current collector foil 5, and the negative electrode current collector foil 6 are each sheet-shaped, and the all-solid-state battery 1, which is a laminate of these components, is also sheet-shaped. The all-solid-state battery 1 may be provided by rolling up the sheet-shaped laminate and housing it in a cylindrical container.

[0010] The solid electrolyte layer 2 is a solid phase sandwiched between the positive electrode layer 3 and the negative electrode intermediate layer 4. The solid electrolyte layer 2 functions as a separator between the positive electrode and the negative electrode in the all-solid-state battery 1 and has lithium ion conductivity. The material of the solid electrolyte layer 2 is not particularly limited as long as it functions as an electrolyte in the battery. In this embodiment, the solid electrolyte layer 2 is a sulfide solid electrolyte, but is not limited thereto. For example, the solid electrolyte layer 2 may be formed from an oxide. The solid electrolyte layer 2 is produced, for example, by weighing and mixing predetermined amounts of a sulfide solid electrolyte, a binder, and an organic solvent to prepare a slurry, which is then applied and dried.

[0011] Furthermore, the solid electrolyte layer 2 is configured to have a larger outer shape than the positive electrode layer 3 and the negative electrode intermediate layer 4, thereby more reliably insulating the positive electrode and the negative electrode in the all-solid-state battery 1 from each other.

[0012] The positive electrode layer 3 is laminated on one surface of the solid electrolyte layer 2 (on the upper surface in the drawing) so as to be in contact with the solid electrolyte layer 2. The positive electrode layer 3 contains a positive electrode active material and functions as an electrode. The positive electrode layer 3 is produced, for example, by weighing and mixing predetermined amounts of a positive electrode active material, a sulfide solid electrolyte, a conductive additive, a binder, and an organic solvent to prepare a slurry, which is then applied to the positive electrode current collector foil 5 and dried. The positive electrode layer 3 is configured to release lithium ions during charging and to occlude lithium during discharging.

[0013] The negative electrode intermediate layer 4 is laminated on the other surface of the solid electrolyte layer 2 (on the bottom surface in the figure) so as to be in contact with the solid electrolyte layer 2. The negative electrode intermediate layer 4 is a layer that assists in smooth deposition of lithium metal and / or protects the solid electrolyte layer 2 so that the deposited lithium metal does not come into direct contact with the solid electrolyte layer 2. The negative electrode intermediate layer 4 contains a material capable of absorbing and desorbing lithium ions, or a material having electronic insulating properties and lithium ion conductivity. The material capable of absorbing and desorbing lithium ions contains one or more materials selected from the group consisting of a carbon material (carbon) such as graphite and a metal material such as silver. The material having electronic insulating properties and lithium ion conductivity is also a material that is more stable against reductive decomposition due to contact with lithium metal than the solid electrolyte contained in the solid electrolyte layer 2. The negative electrode intermediate layer 4 is produced, for example, by weighing and mixing predetermined amounts of metal particles, carbon, a binder, and an organic solvent to prepare a slurry, applying the slurry, and drying it.

[0014] The positive electrode current collector foil 5 and the negative electrode current collector foil 6 are provided to electrically connect the all-solid-state battery 1 to an external device. Although not shown, the positive electrode current collector foil 5 and the negative electrode current collector foil 6 are each connected to a tab at one end, and are electrically connected to the external device via the tab.

[0015] The positive electrode current collector foil 5 is formed of a conductive thin film, and may be, for example, aluminum foil, but is not limited to this. The positive electrode current collector foil 5 is laminated so as to contact the surface of the positive electrode layer 3 opposite to the side that contacts the solid electrolyte layer 2.

[0016] The negative electrode current collector foil 6 is formed of a conductive thin film, and although a stainless steel thin film, a copper thin film, or the like can be used, in this embodiment, copper or a material containing copper is particularly used. The negative electrode current collector foil 6 is laminated so as to contact the surface of the negative electrode intermediate layer 4 opposite to the side that contacts the solid electrolyte layer 2 (the lower surface in the drawing).

[0017] The negative electrode current collector foil 6 is configured to have an outer shape larger than that of the negative electrode intermediate layer 4, and an outer peripheral edge 61 of the negative electrode current collector foil 6 is in contact with the outer peripheral edge of the solid electrolyte layer 2. That is, the negative electrode current collector foil 6 is configured to cover the negative electrode intermediate layer 4. Details of the connection between the outer peripheral edge 61 of the negative electrode current collector foil 6 and the outer peripheral edge of the solid electrolyte layer 2 will be described later.

[0018] The location where the negative electrode current collector foil 6, the negative electrode intermediate layer 4, the solid electrolyte layer 2, the positive electrode layer 3, and the positive electrode current collector foil 5 of the all-solid-state battery 1 are stacked is pressurized in the stacking direction by a pressurizing mechanism (not shown) including a pressure plate, etc. The all-solid-state battery 1 is housed inside an exterior body (not shown).

[0019] In the all-solid-state battery 1 configured as described above, the positive electrode active material contained in the positive electrode layer 3 serves as a lithium ion supply source. During charging, lithium ions migrate from the positive electrode layer 3 to the negative electrode current collector foil 6 side through the solid electrolyte layer 2 and the negative electrode intermediate layer 4. As a result, lithium metal is deposited on the surface of the negative electrode intermediate layer 4, and a metal layer is formed between the negative electrode intermediate layer 4 and the negative electrode current collector foil 6. During discharging, on the other hand, in contrast to during charging, lithium ions migrate from the metal layer formed by the lithium metal deposited on the surface of the negative electrode intermediate layer 4 to the positive electrode layer 3 side, and are absorbed into the positive electrode layer 3.

[0020] In a metal deposition-type all-solid-state battery in which an alkali metal such as lithium metal is deposited on the negative electrode side during charging, even if a negative electrode intermediate layer is used, alkali metal may also deposit and grow on the edge (side) of the negative electrode intermediate layer during charging. Here, the outside of the edge of the negative electrode intermediate layer is a portion of the all-solid-state battery that is not pressurized. Therefore, the alkali metal deposited on the edge of the negative electrode intermediate layer during charging does not return to the positive electrode during discharge and becomes alkali metal that does not contribute to the charge / discharge reaction. This may result in a decrease in charge / discharge capacity. Furthermore, if the deposited alkali metal reaches the positive electrode layer or the positive electrode current collector foil, it may lead to a cell short circuit. For example, in a conventional lithium deposition-type all-solid-state battery 1' in which a negative electrode current collector foil 6', a negative electrode intermediate layer 4', a solid electrolyte layer 2', a positive electrode layer 3', and a positive electrode current collector foil 5' are stacked, lithium ions (Li ＋ ), lithium metal (Li) is also deposited on the 4' end (side surface) of the negative electrode intermediate layer. Because the outside of the 4' end of the negative electrode intermediate layer is a non-pressurized portion, lithium metal (Li) deposited on the 4' end of the negative electrode intermediate layer may not return to the positive electrode during discharge, resulting in a decrease in charge / discharge capacity. Furthermore, for example, lithium metal (Li) deposited on the 4' end of the negative electrode intermediate layer may grow and reach the positive electrode layer 3' or the positive electrode current collector foil 5' from the outside of the end of the solid electrolyte layer 2', potentially resulting in a cell short circuit.

[0021] In contrast, in the all-solid-state battery 1 of this embodiment, the negative electrode current collector foil 6 is configured to cover the negative electrode intermediate layer 4, and the portion of the outer circumferential edge 61 that is not in contact with the negative electrode intermediate layer 4 is in contact with the outer circumferential edge of the solid electrolyte layer 2. This reduces the space in which lithium metal precipitates at the end of the negative electrode intermediate layer 4 compared to when the outer circumferential edge 61 of the negative electrode current collector foil 6 is not in contact with the outer circumferential edge of the solid electrolyte layer 2, making it possible to suppress lithium metal precipitation at the end (side surface) of the negative electrode intermediate layer 4 during charging. Therefore, the amount of lithium metal that does not contribute to the charge / discharge reaction is reduced, making it possible to suppress a decrease in the charge / discharge capacity of the all-solid-state battery 1. Furthermore, because lithium metal precipitation is suppressed at the end (side surface) of the negative electrode intermediate layer 4, cell short-circuiting can be suppressed.

[0022] The connection structure between the outer periphery 61 of the negative electrode current collector foil 6 and the outer periphery of the solid electrolyte layer 2 will be described in detail below.

[0023] As described above, the solid electrolyte layer 2 and the negative electrode current collector foil 6 are configured to have larger outer shapes than the negative electrode intermediate layer 4, and the negative electrode current collector foil 6 is configured to cover the negative electrode intermediate layer 4. Furthermore, the portion of the outer circumferential edge 61 of the negative electrode current collector foil 6 that is not in contact with the negative electrode intermediate layer 4 is in contact with the outer circumferential edge of the solid electrolyte layer 2.

[0024] Specifically, as shown in FIG. 1 , the outer peripheral edge 61 of the negative electrode current collector foil 6 is bent toward the solid electrolyte layer 2 and has a first outer peripheral edge 61A that contacts the entire surface of the negative electrode intermediate layer 4 and a second outer peripheral edge 61B that does not contact the negative electrode intermediate layer 4. The second outer peripheral edge 61B extends from the first outer peripheral edge 61A while contacting the outer peripheral edge of the solid electrolyte layer 2. Because the first outer peripheral edge 61A contacts the entire surface of the negative electrode intermediate layer 4, there is no space between the end (side surface) of the negative electrode intermediate layer 4 and the negative electrode current collector foil 6. That is, there is no space for lithium metal to deposit at the end (side surface) of the negative electrode intermediate layer 4, and lithium metal does not deposit at the end (side surface) of the negative electrode intermediate layer 4 during charging of the all-solid-state battery 1. Therefore, compared to when lithium metal deposits at the end (side surface) of the negative electrode intermediate layer 4, the amount of lithium metal that does not contribute to the charge / discharge reaction is reduced, and a decrease in the charge / discharge capacity of the all-solid-state battery 1 is suppressed. Furthermore, because lithium metal is not deposited on the end (side surface) of the negative electrode intermediate layer 4, the deposited lithium metal is prevented from reaching the positive electrode layer 3 or the positive electrode current collector foil 5 and causing a cell short circuit. Although the negative electrode current collector foil 6 is compressed by air pressure, the all-solid-state battery 1 is provided with a buffer material (not shown) or the like that allows for a change in thickness in the stacking direction. Therefore, lithium metal is deposited between the negative electrode intermediate layer 4 and the negative electrode current collector foil 6 in the stacking direction.

[0025] The negative electrode current collector foil 6 is configured so that the electronic conductivity of the second outer peripheral edge 61B, which is not in contact with the negative electrode intermediate layer 4, is lower than the electronic conductivity of the portion of the negative electrode current collector foil 6 that is in contact with the negative electrode intermediate layer 4. In detail, the second outer peripheral edge 61B of the negative electrode current collector foil 6 has, on the surface facing the solid electrolyte layer 2, copper sulfide (CuS or Cu ２A coating 62 (S) is formed on the negative electrode current collector foil 6, and has lower electrical conductivity than other portions (portions in contact with the negative electrode intermediate layer 4). This suppresses lithium metal deposition on the surface of the second outer peripheral edge 61B of the negative electrode current collector foil 6 facing the solid electrolyte layer 2. If lithium metal deposits on the surface of the second outer peripheral edge 61B of the negative electrode current collector foil 6 facing the solid electrolyte layer 2 (between the second outer peripheral edge 61B and the solid electrolyte layer 2), the deposited lithium metal becomes lithium that does not contribute to charge / discharge reactions. In contrast, in this embodiment, lithium metal deposition is suppressed on the surface of the second outer peripheral edge 61B facing the solid electrolyte layer 2, reducing the amount of lithium that does not contribute to charge / discharge reactions, thereby further suppressing a decrease in the charge / discharge capacity of the all-solid-state battery 1. Furthermore, suppressing lithium metal deposition on the surface of the second outer peripheral edge 61B further suppresses cell short-circuiting.

[0026] Furthermore, the coating 62 is configured as a part of the negative electrode current collector foil 6, and is not a separate component interposed between the negative electrode current collector foil 6 and the solid electrolyte layer 2. Therefore, the second outer peripheral edge 61B is in direct contact with the outer peripheral edge of the solid electrolyte layer 2, and the thickness of the portion of the negative electrode current collector foil 6 that is in contact with the negative electrode intermediate layer 4 is equal to the thickness of the second outer peripheral edge 61B that is not in contact with the negative electrode intermediate layer 4. If a thick component such as an insulating material is interposed between the outer peripheral edge 61 of the negative electrode current collector foil 6 and the solid electrolyte layer 2, a difference in level will occur between the portion where the insulating material is interposed and the other portions. This may result in deformation and cracking of the solid electrolyte layer during pressing during manufacturing or prototyping of the all-solid-state battery. In contrast, in the present embodiment, the thickness of the portion of the negative electrode current collector foil 6 that is in contact with the negative electrode intermediate layer 4 is equal to the thickness of the second outer peripheral edge 61B that is not in contact with the negative electrode intermediate layer 4, and there is no step between the negative electrode current collector foil 6 and the solid electrolyte layer 2. This prevents the solid electrolyte layer 2 from being deformed and cracked during pressing. Furthermore, since no insulating material or the like is interposed, the weight energy density is improved and costs are reduced.

[0027] In this embodiment, the coating 62 is a copper sulfide coating, but the present invention is not limited to this, and the coating 62 may be made of other copper compounds having higher electrical resistivity than copper or materials containing copper. For example, the coating 62 may be made of copper oxide.

[0028] As described above, in the all-solid-state battery 1 of this embodiment, the anode intermediate layer 4 is covered with the anode current collector foil 6, and the outer peripheral edge 61 of the anode current collector foil 6 has a first outer peripheral edge 61A that contacts the front of the side surface of the anode intermediate layer 4 and a second outer peripheral edge 61B that is not in contact with the anode intermediate layer 4, and the second outer peripheral edge 61B is in contact with the outer peripheral edge of the solid electrolyte layer 2. Therefore, there is no space for lithium metal to precipitate at the end (side surface) of the anode intermediate layer 4, and lithium metal does not precipitate at the end (side surface) of the anode intermediate layer 4 during charging of the all-solid-state battery 1. This reduces the amount of lithium metal that does not contribute to the charge / discharge reaction, and suppresses a decrease in the charge / discharge capacity of the all-solid-state battery 1. Furthermore, because lithium metal does not precipitate at the end (side surface) of the anode intermediate layer 4, cell short-circuiting is prevented.

[0029] According to the all-solid-state battery 1 of the above-described embodiment, the following effects can be obtained.

[0030] In the all-solid-state battery 1, the solid electrolyte layer 2 and the negative electrode current collector foil 6 have larger outer dimensions than the negative electrode intermediate layer 4, and the negative electrode current collector foil 6 is configured to cover the negative electrode intermediate layer 4. The second outer peripheral edge (outer peripheral edge) 61B, which is not in contact with the negative electrode intermediate layer 4, is in contact with the outer peripheral edge of the solid electrolyte layer 2. This reduces the space in which lithium metal precipitates at the end of the negative electrode intermediate layer 4 compared to when the second outer peripheral edge (outer peripheral edge) 61B of the negative electrode current collector foil 6 is not in contact with the outer peripheral edge of the solid electrolyte layer 2, thereby suppressing lithium metal precipitation at the end (side surface) of the negative electrode intermediate layer 4 during charging. This reduces the amount of lithium metal that does not contribute to the charge / discharge reaction, thereby suppressing a decrease in the charge / discharge capacity of the all-solid-state battery 1. Furthermore, suppressing lithium metal precipitation at the end (side surface) of the negative electrode intermediate layer 4 also suppresses cell short-circuiting.

[0031] The all-solid-state battery 1 has a first outer peripheral edge 61A that bends toward the solid electrolyte layer 2 and contacts the entire side surface of the anode intermediate layer 4. A second outer peripheral edge (outer peripheral edge) 61B that does not contact the anode intermediate layer 4 extends from the first outer peripheral edge 61A while contacting the outer peripheral edge of the solid electrolyte layer 2. Because the first outer peripheral edge 61A contacts the entire surface of the anode intermediate layer 4, there is no space for lithium metal to deposit at the end (side surface) of the anode intermediate layer 4, and lithium metal does not deposit at the end (side surface) of the anode intermediate layer 4 during charging of the all-solid-state battery 1. Therefore, compared to when lithium metal deposits at the end (side surface) of the anode intermediate layer 4, the amount of lithium metal that does not contribute to the charge / discharge reaction is reduced, and a decrease in the charge / discharge capacity of the all-solid-state battery 1 is suppressed. Furthermore, because lithium metal does not deposit at the end (side surface) of the anode intermediate layer 4, the deposited lithium metal is prevented from reaching the positive electrode layer 3 or the positive electrode current collector foil 5 and causing a cell short circuit.

[0032] In the all-solid-state battery 1, the negative electrode intermediate layer 4 contains metal and carbon, which allows the negative electrode to absorb and release lithium ions, thereby forming a negative electrode deposition-type all-solid-state battery.

[0033] In the all-solid-state battery 1, the electronic conductivity of the second outer peripheral edge (outer peripheral edge) 61B of the negative electrode current collector foil 6 that is not in contact with the negative electrode intermediate layer 4 is lower than the electronic conductivity of the portion in contact with the negative electrode intermediate layer 4. This suppresses lithium metal deposition on the surface of the second outer peripheral edge (outer peripheral edge) 61B of the negative electrode current collector foil 6 that faces the solid electrolyte layer 2. This reduces lithium that does not contribute to charge / discharge reactions, making it possible to further suppress a decrease in the charge / discharge capacity of the all-solid-state battery 1. Furthermore, because lithium metal deposition on the surface of the second outer peripheral edge (outer peripheral edge) 61B is reduced, cell short-circuiting can be further suppressed.

[0034] In the all-solid-state battery 1, the thickness of the second outer peripheral edge (outer peripheral edge) 61B of the negative electrode current collector foil 6 that is not in contact with the negative electrode intermediate layer 4 is equal to the thickness of the portion that is in contact with the negative electrode intermediate layer 4, and the second outer peripheral edge (outer peripheral edge) 61B that is not in contact with the negative electrode intermediate layer 4 is in direct contact with the solid electrolyte layer 2. That is, no thick member such as an insulating material is interposed between the second outer peripheral edge (outer peripheral edge) 61B of the negative electrode current collector foil 6 and the solid electrolyte layer 2. This prevents the solid electrolyte layer 2 from deforming and cracking during pressing. Furthermore, the absence of an insulating material or the like improves weight energy density and reduces costs.

[0035] In the all-solid-state battery 1, the negative electrode current collector foil 6 is made of copper or a material containing copper, and the second outer peripheral edge (outer peripheral edge) 61B, which is not in contact with the negative electrode intermediate layer 4, contains a copper compound on the surface facing the solid electrolyte layer 2. That is, the second outer peripheral edge (outer peripheral edge) 61B contains a copper compound with high electrical resistivity on the surface facing the solid electrolyte layer 2. This suppresses lithium metal deposition on the surface of the second outer peripheral edge 61B of the negative electrode current collector foil 6 facing the solid electrolyte layer 2, reducing lithium that does not contribute to charge / discharge reactions and further suppressing a decrease in the charge / discharge capacity of the all-solid-state battery 1. Furthermore, because lithium metal deposition on the surface of the second outer peripheral edge (outer peripheral edge) 61B is suppressed, cell short-circuiting can be further suppressed.

[0036] In the all-solid-state battery 1, the negative electrode current collector foil 6 is made of copper or a material containing copper, and the second outer peripheral edge (outer peripheral edge) 61B, which is not in contact with the negative electrode intermediate layer 4, contains copper sulfide on the surface facing the solid electrolyte layer 2. That is, the second outer peripheral edge (outer peripheral edge) 61B contains copper sulfide, which has high electrical resistivity, on the surface facing the solid electrolyte layer 2. This suppresses lithium metal deposition on the surface of the second outer peripheral edge 61B of the negative electrode current collector foil 6 facing the solid electrolyte layer 2, reducing lithium that does not contribute to charge / discharge reactions and further suppressing a decrease in the charge / discharge capacity of the all-solid-state battery 1. Furthermore, because lithium metal deposition on the surface of the second outer peripheral edge (outer peripheral edge) 61B is suppressed, cell short-circuiting can be further suppressed.

[0037] As in the present embodiment, it is preferable that the outer peripheral edge 61 of the negative electrode current collector foil 6 has a first outer peripheral edge 61A that contacts the entire surface of the negative electrode intermediate layer 4 and a second outer peripheral edge 61B that does not contact the negative electrode intermediate layer 4, but this is not necessarily limited to this. For example, as shown in Figures 3 and 4, even if the outer peripheral edge 61 of the negative electrode current collector foil 6 has a configuration in which there is no portion that contacts the negative electrode intermediate layer 4, it is sufficient that at least a portion of the outer peripheral edge 61 of the negative electrode current collector foil 6 contacts the outer peripheral edge of the solid electrolyte layer 2. In these cases, although a space exists between the end (side surface) of the negative electrode intermediate layer 4 and the negative electrode current collector foil 6, the size of this space is smaller than when the outer peripheral edge 61 of the negative electrode current collector foil 6 does not contact the outer peripheral edge of the solid electrolyte layer 2. That is, compared to when the outer peripheral edge 61 of the negative electrode current collector foil 6 is not in contact with the outer peripheral edge of the solid electrolyte layer 2, the space in which lithium metal precipitates at the end of the negative electrode intermediate layer 4 is reduced, and therefore, even in these cases, it is possible to suppress the precipitation of lithium metal at the end (side surface) of the negative electrode intermediate layer 4 during charging. Therefore, the amount of lithium metal that does not contribute to the charge / discharge reaction is reduced, and it is possible to suppress a decrease in the charge / discharge capacity of the all-solid-state battery 1. Furthermore, because the precipitation of lithium metal at the end (side surface) of the negative electrode intermediate layer 4 is suppressed, it is possible to suppress a cell short circuit.

[0038] Furthermore, in all of the drawings of this embodiment, the thickness of the negative electrode intermediate layer 4 is shown to be greater than the thickness of the negative electrode current collector foil 6, but preferably, the negative electrode intermediate layer 4 is configured to be thinner than the negative electrode current collector foil 6. This makes it easier to bend the negative electrode current collector foil 6 and bring it into contact with the outer periphery of the solid electrolyte layer 2, compared to when the negative electrode intermediate layer 4 is thicker than the negative electrode current collector foil 6. Furthermore, by configuring the negative electrode intermediate layer 4 to be thin, the energy density can be improved.

[0039] Furthermore, as in the present embodiment, it is preferable that the electronic conductivity of the second outer peripheral edge 61B of the negative electrode current collector foil 6 that is not in contact with the negative electrode intermediate layer 4 is configured to be lower than the electronic conductivity of the portion of the negative electrode current collector foil 6 that is not in contact with the negative electrode intermediate layer 4, but this is not necessarily limited to this. Even if the electronic conductivity of the second outer peripheral edge 61B is not lower than the electronic conductivity of the other portions of the negative electrode current collector foil 6, as long as at least a portion of the outer peripheral edge 61 of the negative electrode current collector foil 6 is in contact with the outer peripheral edge of the solid electrolyte layer 2, deposition of lithium metal on the side surface of the negative electrode intermediate layer 4 can be suppressed.

[0040] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

Claims

1. An all-solid-state battery having a solid electrolyte layer, a positive electrode layer and a negative electrode intermediate layer disposed so as to sandwich the solid electrolyte layer, and a negative electrode current collector foil disposed on the negative electrode intermediate layer, wherein the solid electrolyte layer and the negative electrode current collector foil have larger outer shapes than the negative electrode intermediate layer, and the negative electrode current collector foil is configured to cover the negative electrode intermediate layer, and at least a portion of the outer periphery that is not in contact with the negative electrode intermediate layer is in contact with the outer periphery of the solid electrolyte layer.

2. An all-solid-state battery according to claim 1, wherein the negative electrode current collector foil has a first outer peripheral edge that is bent toward the solid electrolyte layer and in contact with the entire side surface of the negative electrode intermediate layer, and the outer peripheral edge that is not in contact with the negative electrode intermediate layer extends from the first outer peripheral edge while in contact with the outer peripheral edge of the solid electrolyte layer.

3. The all-solid-state battery according to claim 1 or 2, wherein the negative electrode intermediate layer contains a metal and carbon.

4. The all-solid-state battery according to claim 1 or 2, wherein the negative electrode intermediate layer is thinner than the negative electrode current collector foil.

5. An all-solid-state battery according to claim 1 or 2, wherein the electronic conductivity of the outer periphery of the negative electrode current collector foil that is not in contact with the negative electrode intermediate layer is lower than the electronic conductivity of the portion of the negative electrode current collector foil that is in contact with the negative electrode intermediate layer.

6. An all-solid-state battery according to claim 5, wherein the thickness of the outer periphery of the negative electrode current collector foil that is not in contact with the negative electrode intermediate layer is equal to the thickness of the portion that is in contact with the negative electrode intermediate layer, and the outer periphery that is not in contact with the negative electrode intermediate layer is in direct contact with the solid electrolyte layer.

7. An all-solid-state battery according to claim 6, wherein the negative electrode current collector foil is made of copper or a material containing copper, and the outer edge not in contact with the negative electrode intermediate layer contains a copper compound on the surface facing the solid electrolyte layer.

8. An all-solid-state battery according to claim 7, wherein the outer peripheral edge not in contact with the negative electrode intermediate layer contains copper sulfide on the surface facing the solid electrolyte layer.

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