All-solid-state battery and method for manufacturing the same

Abstract

Provided is an all-solid-state battery comprising: a laminate configured such that a first electrode layer, a solid electrolyte layer, and a second electrode layer are laminated in a lamination region; and an exterior material that accommodates the laminate. The laminate is provided with an insulating frame structure surrounding the first electrode layer in the outermost portion in the surface direction as an outermost-portion frame structure. An outer peripheral end surface of the outermost-portion frame structure is inclined. The outermost-portion frame structure is substantially rectangular and the inclination angle of the outer peripheral end surface on the short side is larger than the inclination angle of the outer peripheral end surface on the long side.

Description

[[Technical Field]]

[0001] The present invention relates to an all-solid battery and a method for manufacturing the same. [[Background Art]]

[0002] An all-solid battery is a secondary battery that uses a solid electrolyte as the electrolyte. There is known an all-solid battery including a layered product having a stacked structure of a positive electrode layer, a solid electrolyte layer, and a negative electrode layer, and an exterior material that houses the layered product. A film-like material may be used as the exterior material. In an all-solid battery having such a configuration, the exterior material may interfere with the layered product, resulting in damage to the exterior material or the layered product.

[0003] As a technique for preventing damage caused by interference between the exterior material and the layered product, the technique described in Patent Document 1 (JP2014-44920A) can be mentioned. This document discloses a sealed battery including an electrode body, an exterior case that houses the electrode body in a sealed state inside, and an elastic body filled inside the exterior case in a state of covering the entire electrode body. [[Summary of the Invention]]

[0004] As described in Patent Document 1, when an elastic body is disposed so as to cover the entire electrode body (layered product), the volume increases and the energy density decreases.

[0005] Therefore, an object of the present invention is to provide a technique capable of preventing damage caused by interference between the layered product and the exterior material without lowering the energy density.

[0006] In one embodiment, the all-solid-state battery according to the present invention comprises a laminate having a configuration in which at least one first electrode layer, at least one solid electrolyte layer, and at least one second electrode layer are laminated in a laminated region, and an outer casing material that houses the laminate. One of the first electrode layer and the second electrode layer is a positive electrode layer, and the other is a negative electrode layer. When viewed along the laminated direction, the laminated region is substantially rectangular. Of the at least one first electrode layer, the electrode layer located on the outermost side in the laminated direction is defined as the outermost first electrode layer. The laminate is further provided with an outermost frame structure, which is an insulating frame structure that surrounds the outermost first electrode layer in the planar direction. The outer peripheral end faces of the outermost frame structure are inclined such that the thickness of the outermost frame structure decreases towards the outside. The inclination angle of the outer peripheral end faces on the short side of the outermost frame structure is greater than the inclination angle of the outer peripheral end faces on the long side of the outermost frame structure. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic cross-sectional view showing an all-solid-state battery according to an embodiment. [Figure 2] Figure 2 is a schematic plan view showing an all-solid-state battery according to this embodiment. [Figure 3A] Figure 3A is a schematic cross-sectional view showing a portion of section AA in Figure 2. [Figure 3B] Figure 3B is a schematic cross-sectional view showing a portion of the BB section in Figure 2. [Figure 4] Figure 4 shows a modified example of the frame structure. [Figure 5] Figure 5 is a schematic cross-sectional view showing a modified example of the battery compartment frame structure. [Figure 6] Figure 6 is a schematic cross-sectional view showing a modified example of the laminated structure in a laminate. [Figure 7] Figure 7 is a schematic diagram illustrating the method for creating a frame structure. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described below with reference to the drawings. Figure 1 is a schematic cross-sectional view showing an all-solid-state battery 1 according to this embodiment. As shown in Figure 1, the all-solid-state battery 1 has a laminate 2 and an outer casing material 3 that houses the laminate 2.

[0009] The laminate 2 has a configuration in which at least one first electrode layer 6, at least one solid electrolyte layer 8, and at least one second electrode layer 7 are laminated in a laminate region 20. One of the first electrode layer 6 and the second electrode layer 7 is a positive electrode layer, and the other is a negative electrode layer.

[0010] In this specification, "all-solid-state battery" refers to a battery that primarily uses a solid electrolyte, but may also contain a small amount of liquid electrolyte in addition to the solid electrolyte.

[0011] Specifically, in the laminated region 20, multiple first current collector foils 4 and multiple second current collector foils 5 are arranged alternately along the lamination direction. A single cell 11 is sandwiched between adjacent first current collector foils 4 and second current collector foils 5. The single cell 11 consists of a first electrode layer 6, a second electrode layer 7, and a solid electrolyte layer 8. In the single cell 11, the solid electrolyte layer 8 is sandwiched between the first electrode layer 6 and the second electrode layer 7. The single cell 11 is positioned between the first current collector foil 4 and the second current collector foil 5 such that the first electrode layer 6 is in contact with the first current collector foil 4 and the second electrode layer 7 is in contact with the second current collector foil 5. Of the first current collector foils 4 and the second current collector foils 5, the outermost current collector foil in the lamination direction is the first current collector foil 4. A first electrode layer 6 is also formed on the outside of this outermost first current collector foil 4. In other words, the outermost layer in the laminate 2 is the first electrode layer 6.

[0012] In other words, in the laminated region 20, a first current collector foil 4, on which a first electrode layer 6 is formed on both sides, and a second current collector foil 5, on which a second electrode layer 7 is formed on both sides, are alternately laminated with a solid electrolyte layer 8 in between. As a result, a structure is formed in which a single cell 11 is sandwiched between the first current collector foil 4 and the second current collector foil 5. Furthermore, the outermost layer of the laminated body 2 in the lamination direction is the first electrode layer 6.

[0013] In the following description, the electrode layer located on the outermost side in the stacking direction among the multiple first electrode layers 6 is referred to as the "outermost first electrode layer 9". Also, the first electrode layer 6 included in the single cell 11 is referred to as the "battery section first electrode layer 19".

[0014] The first current collector foil 4 and the second current collector foil 5 are provided to electrically connect the single cell 11 to an external device. Each first current collector foil 4 protrudes laterally from the laminated region 20 on one side in a first direction perpendicular to the lamination direction (hereinafter referred to as the first electrode tab side). Multiple first current collector foils 4 are joined together at the end on the first electrode tab side and connected to the first electrode tab 13. On the other hand, each second current collector foil 5 protrudes laterally from the laminated region 20 on the side opposite to the first electrode tab side (hereinafter sometimes referred to as the second electrode tab side). Multiple second current collector foils 5 are joined together at the end on the second electrode tab side and connected to the second electrode tab 14.

[0015] The laminate 2 is further provided with a plurality of frame structures 30 to protect the edges of each first electrode layer 6. Each frame structure 30 is insulating and formed on the first current collector foil 4. Each frame structure 30 is arranged to surround each first electrode layer 6 in the planar direction (a direction perpendicular to the lamination direction). When viewed along the lamination direction, the outer edges of each first electrode layer 6 are located inward from the outer edges of the first current collector foil 4 and the solid electrolyte layer 8. As a result, there is a surplus area on the first current collector foil 4 that overlaps with the solid electrolyte layer 8 but does not have a first electrode layer 6. The frame structures 30 are arranged in this surplus area. When viewed along the lamination direction, the outer edges of the frame structures 30 are at the same position as the outer edges of the first current collector foil 4, or located inward from the outer edges of the first current collector foil 4. When viewed along the lamination direction, the outer edges of the frame structures 30 are aligned with the outer edges of the solid electrolyte layer 8. In other words, when viewed along the lamination direction, the frame structure 30 does not protrude outside the first current collector foil 4 and the solid electrolyte layer 8.

[0016] In the following description, among the multiple frame structures 30, the frame structure 30 provided so as to surround the outermost first electrode layer 9 will be referred to as the "outermost frame structure 10". Also, among the multiple frame structures 30, the frame structure provided in accordance with the single cell 11 (the frame structure provided so as to surround the battery section first electrode layer 19) will be referred to as the "battery section frame structure 12".

[0017] The exterior material 3 is provided to protect the laminate 2. The exterior material 3 has a structure in which a pair of films are sealed around its outer periphery. Specifically, the pair of films constituting the exterior material 3 are arranged so as to sandwich the laminate 2. The pair of films are sealed on the side of the laminate 2. The portion where the pair of films are sealed will be hereinafter referred to as the sealed portion 15.

[0018] Next, the configuration of the all-solid-state battery 1 as viewed along the stacking direction will be described. Figure 2 is a schematic plan view of the all-solid-state battery 1. As shown in Figure 2, the stacking region 20 is approximately rectangular in shape. That is, the first electrode layer 6, the second electrode layer 7, and the solid electrolyte layer 8 are all approximately rectangular in shape. In addition, each frame structure 30 is also approximately rectangular in shape, corresponding to the shape of the first electrode layer 6. The first current collector foil 4 and the second current collector foil 5 are also approximately rectangular in shape. The long sides of the stacking region 20 and each current collector foil (4, 5) are aligned along the first direction. That is, the first current collector foil 4 and the second current collector foil 5 each protrude laterally from the short side of the stacking region 20 and are connected to the respective electrode tabs (13, 14) at their ends in the first direction.

[0019] The sealing portion 15 provided on the outer casing material 3 is also roughly rectangular in shape. The sealing portion 15 is positioned to surround the first current collector foil 4 and the second current collector foil 5 when viewed along the lamination direction. At both ends in the first direction, the sealing portion 15 overlaps each electrode tab (13, 14). That is, the pair of films constituting the outer casing material 3 are partially sealed to each electrode tab (13, 14). On the other hand, at both ends in the second direction, when viewed along the lamination direction, the sealing portion 15 is located very close to each current collector foil (4, 5).

[0020] The above is the overall configuration of the all-solid-state battery 1. One of the features of the present embodiment is the configuration of the outermost frame structure among the plurality of frame structures 30.

[0021] Specifically, as shown in FIG. 1, the outer peripheral end face of the outermost frame structure 10 is inclined such that the thickness of the outermost frame structure 10 decreases toward the outer side. More specifically, the outer peripheral end face is inclined such that the width of the outermost frame structure 10 is larger on the inner side than on the outer side in the stacking direction. Note that FIG. 1 shows an example where the outer peripheral end face of the outermost frame structure 10 is a curved surface. As a result, the end portion of the outermost layer of the stacked body 2 in the stacking direction has a rounded shape.

[0022] As described above, the inclined outer peripheral end face of the outermost frame structure 10 prevents damage to the exterior material 3 and the stacked body 2. As shown in FIG. 1, while the exterior material 3 is sealed at the sealing portion 15, it sandwiches the stacked body 2 in the stacked region 20. Therefore, the exterior material 3 is bent at the end of the stacked region 20. At the bent portion of the exterior material 3, that is, at the end portion of the outermost layer of the stacked body 2, a load applied from the exterior material 3 to the stacked body 2 is likely to concentrate. For example, during manufacturing, while the internal region of the exterior material 3 is depressurized, a pair of films are sealed to form the sealing portion 15. At this time, the load from the exterior material 3 concentrates on the end portion of the outermost layer of the stacked body 2. Alternatively, even after manufacturing, vibration or impact may be applied to the all-solid-state battery 1 from the outside. Even in such a case, a large load is applied from the exterior material 3 to the end portion of the outermost layer of the stacked body 2. As a result, at the end portion of the outermost layer, damage to the stacked body 2 (such as falling off of the active material from the electrode layer) and damage to the exterior material 3 are likely to occur. In contrast, according to the present embodiment, since a frame structure having an inclined outer peripheral end face is disposed as the outermost frame structure 10, the load at the end portion of the outermost layer is dispersed. Therefore, damage to the stacked body 2 and the exterior material 3 can be prevented.

[0023] Furthermore, with the above configuration, an elastic body that completely covers the laminate 2 is not necessary. Therefore, damage to the laminate 2 and the outer material 3 can be prevented without significantly increasing weight or volume.

[0024] In this embodiment, the magnitude of the inclination angles on the long and short sides of the outermost frame structure 10 has been further refined. This will be explained below. Figure 3A is a schematic cross-sectional view showing a part of the AA section of Figure 2, and is a schematic diagram showing the cross-sectional structure on the short side of the outermost frame structure 10. Figure 3B is a schematic cross-sectional view showing a part of the BB section of Figure 2, and is a schematic diagram showing the cross-sectional structure on the long side of the outermost frame structure 10. As shown in Figures 3A and 3B, the inclination angle of the outer peripheral end face on the short side of the outermost frame structure 10 is greater than the inclination angle of the outer peripheral end face on the long side of the outermost frame structure 10. Here, "inclination angle" refers to the angle formed between the outer peripheral end face of the outermost frame structure 10 and the surface of the first current collector foil 4. Furthermore, if the outermost end surface of the outermost frame structure 10 is curved, the angle between the tangent to the outermost frame structure 10 at the outermost point in the first direction (the part where the thickness of the outermost frame structure 10 becomes zero) and the surface of the first current collector foil 4 is specified as the "angle of inclination".

[0025] As described above, the inclination angle of the outer peripheral end face on the shorter side of the outermost frame structure 10 is greater than that on the longer side, which reduces the excess volume of the all-solid-state battery 1. This point will be explained below.

[0026] As shown in Figure 2, the sealing portion 15 of the exterior material 3 is formed very close to the laminated region 20 at both ends in the second direction, for reasons such as reducing volume. Therefore, at the ends (long sides) of the laminated region 20 in the second direction, the exterior material 3 bends at a sharp angle. Because the exterior material 3 bends at a sharp angle, the load from the exterior material 3 is easily applied to the laminated body 2 at the long sides. Therefore, from the viewpoint of sufficiently distributing the load, the inclination angle of the outer peripheral end face at the long side of the outermost frame structure 10 should be small, as shown in Figure 3B.

[0027] On the other hand, at both ends in the first direction, the sealing portion 15 is positioned so as to cross each electrode tab (13, 14). Therefore, the distance between the stacked region 20 and the sealing portion 15 in the first direction is greater than that in the second direction. At the ends (short sides) of the stacked region 20 in the first direction, the bending angle of the outer casing material 3 is not that large. Therefore, the load applied from the outer casing material 3 to the stacked body 2 is not that large. Thus, the inclination angle of the outer peripheral end face on the short side of the outermost frame structure 10 can be relatively large. And if the inclination angle is large, the width of the outermost frame structure 10 can be reduced. This makes it possible to secure a larger area for the first electrode layer 6. As a result, the excess volume of the all-solid-state battery 1 can be reduced.

[0028] The above describes the general configuration of the all-solid-state battery 1 according to this embodiment. Next, the detailed configuration and preferred embodiments of the all-solid-state battery 1 according to this embodiment will be described.

[0029] Referring to Figure 1, the battery section frame structure 12 will be described. As previously stated, the battery section frame structure 12 is a frame structure provided around the electrode layer (battery section first electrode layer 19) included in the single cell 11, among the multiple frame structures 30. The load that the laminate 2 receives from the outer material 3 is greatest at the outermost part in the stacking direction. However, even at points other than the outermost part in the stacking direction, a certain amount of load is indirectly applied to the ends of the first electrode layer 6 from the outer material 3. Also, as shown in Figure 1, each current collector foil (first current collector foil 4 and second current collector foil 5) is bent at the ends of the stacking region 20, except for the current collector foil located in the center in the stacking direction. A load is applied directly or indirectly to the ends of each first electrode layer 6 from the bent parts of each current collector foil (4, 5). In other words, the battery section first electrode layer 19 also receives a certain amount of load at its ends from the outer material 3 and each current collector foil (4, 5). Therefore, the active material is prone to falling off. For this reason, it is preferable to provide a battery section frame structure 12 around the battery section's first electrode layer 19 to protect the edges of the battery section's first electrode layer 19.

[0030] The outer peripheral end surface of the battery section frame structure 12 is preferably inclined such that, similar to the outermost frame structure 10, the thickness of the battery section frame structure 12 decreases towards the outside in the surface direction. However, it is preferable that the outer peripheral end surface of the battery section frame structure 12 is inclined such that the width of the battery section frame structure 12 widens on the first current collector foil 4 side and narrows on the opposite side (solid electrolyte layer 8 side). This configuration prevents interference between the end of the battery section frame structure 12 and the end of the solid electrolyte layer 8, thereby preventing damage to both. It is also preferable that the outer peripheral end surface of the battery section frame structure 12 is curved, similar to the outermost frame structure 10.

[0031] Regarding other aspects, the configuration of the battery section frame structure 12 can be basically the same as that of the outermost frame structure 10. That is, the battery section frame structure 12 is roughly rectangular in shape, corresponding to the shape of the first electrode layer 6. The inclination angle of the outer edge of the battery section frame structure 12 is large on the short side and small on the long side. When viewed along the stacking direction, the outer edge of the battery section first electrode layer 19 is located inside the outer edge of the first current collector foil 4. The battery section frame structure 12 is provided in the region on the first current collector foil 4 that overlaps with the solid electrolyte layer 8 but where the battery section first electrode layer 19 is not provided. When viewed along the stacking direction, the outer edge of the battery section frame structure 12 is in the same position as the outer edge of the first current collector foil 4, or located inside the outer edge of the first current collector foil 4. When viewed along the stacking direction, the outer edge of the battery section frame structure 12 is aligned with the outer edge of the solid electrolyte layer 8. In other words, the battery frame structure 12 does not protrude outside the first current collector foil 4 and the solid electrolyte layer 8. With this configuration, there is almost no increase in area or volume due to the provision of the battery frame structure 12, so the edges of each first electrode layer 6 can be protected without significantly reducing the energy density.

[0032] Next, a preferred shape for the frame structure 30 will be described. In the following, when it is not necessary to distinguish between the outermost frame structure 10 and the battery section frame structure 12, it will simply be referred to as the frame structure 30. As shown in Figure 2, when viewed along the stacking direction, the frame structure 30 has four corners 16. It is preferable that each of these four corners 16 has a rounded shape. By having rounded corners 16, the load applied from the outer material 3 to the laminate 2 is more easily distributed, damage to the laminate 2 during impacts, etc., is more reliably prevented, and short circuits due to damage are also more reliably prevented. The curvature of each corner 16 is, for example, 1 to 3, preferably 1.5 to 2.5. Within this range, the load can be sufficiently distributed while ensuring a sufficient area for the first electrode layer 6. In one embodiment, the curvature of each corner 16 is 2 or more.

[0033] Next, a modified example of the frame structure 30 will be described. Figure 4 shows a modified example of the frame structure 30. When viewed along the lamination direction, the width at each corner 16 is wider than the width at the other parts. By adopting this configuration, damage to the laminate 2 can be prevented more reliably even if impact or vibration is applied to the corners 16 during handling, etc.

[0034] Figure 5 is a schematic cross-sectional view showing a modified example of the battery section frame structure 12, and shows the end of the single cell 11 and its surrounding area. In this modified example, when viewed along the stacking direction, the outer peripheral end of the battery section frame structure 12 on the first electrode tab side in the first direction is located outside the outer peripheral end of the second current collector foil 5. Also, the outer peripheral end of the battery section frame structure 12 is located outside the bent portion of the first current collector foil 4 (see "bent portion 17" in Figure 5). With this configuration, short circuits due to contact between the first current collector foil 4 and the second current collector foil 5 are prevented.

[0035] Next, a modified example of the laminated structure in the laminate 2 will be described. Figure 6 is a schematic cross-sectional view showing a modified example of the laminated structure in the laminate 2. In the example shown in Figure 1, the case where the outermost layer of the laminate 2 in the lamination direction is the first electrode layer 6 was described. In contrast, in this modified example, the outermost layer of the laminate 2 is the second current collector foil 5. That is, in the laminate 2, from the outermost part in the lamination direction, the layers are arranged in the following order: second current collector foil 5, second electrode layer 7, solid electrolyte layer 8, first electrode layer 6, and first current collector foil 4.

[0036] In the modified example shown in Figure 6, the outermost electrode layer among the multiple first electrode layers 6 can be said to be the outermost first electrode layer 9. The frame structure 30 provided around this outermost first electrode layer 9 can be said to be the outermost frame structure 10. However, in this modified example, the outermost first electrode layer 9 is also an electrode layer that constitutes a single cell 11. Therefore, the outermost first electrode layer 9 can also be said to be the battery section first electrode layer 19. The outermost frame structure 10 can also be said to be the battery section frame structure 12. In other respects, it has the same configuration as the example shown in Figure 1.

[0037] In this modified example, the outermost first electrode layer 9 is not the outermost layer in the laminate 2. That is, outside the outermost first electrode layer 9 in the lamination direction, there are further solid electrolyte layer 8, second electrode layer 7, and second current collector foil 5. However, if the thickness of the solid electrolyte layer 8, second electrode layer 7, and second current collector foil 5 is thin, the load from the outer covering material 3 is indirectly applied to the edge of the outermost first electrode layer 9. Therefore, damage due to interference between the outer covering material 3 and the edge of the outermost first electrode layer 9 may occur. For this reason, even when the outermost layer is not the outermost first electrode layer 9, as in this modified example, it is worthwhile to provide an outermost frame structure 10 with an inclined outer peripheral end surface to distribute the load.

[0038] Next, the number of individual cells 11 included in the laminate 2 will be described. In the embodiments and modifications described above, the case in which the all-solid-state battery 1 includes multiple individual cells 11 has been described. However, the individual cells 11 included in the all-solid-state battery 1 may be single. That is, the first current collector foil 4, the second current collector foil 5, the first electrode layer 6, the second electrode layer 7, and the solid electrolyte layer 8 may each be single. In this case, the only first electrode layer 6 included in the laminate 2 becomes the outermost first electrode layer 9. And it is sufficient that the outermost frame structure 10 is provided around this single first electrode layer 6.

[0039] The first electrode layer 6 may be a positive electrode layer or a negative electrode layer. However, preferably, the first electrode layer 6 is a positive electrode layer. That is, it is preferable that the outermost frame structure 10 is provided around the outermost positive electrode layer. In all-solid-state batteries, the thickness of the positive electrode layer is often greater than the thickness of the negative electrode layer. Due to its greater thickness, the positive electrode layer is more susceptible to the effects of load from the outer casing material 3 than the negative electrode layer. Therefore, by arranging the frame structure 30 around the positive electrode layer and distributing the load, damage to the all-solid-state battery 1 can be prevented more reliably.

[0040] Next, a method for manufacturing the all-solid-state battery 1 will be described. The method for manufacturing the all-solid-state battery 1 is not particularly limited. For example, after manufacturing a laminate 2 having the above-described structure, the all-solid-state battery 1 can be obtained by housing the laminate 2 in an outer casing material 3. In manufacturing the laminate 2, first, a first electrode layer 6 and a frame structure 30 are formed on the first current collector foil 4. Then, other materials such as a solid electrolyte layer 8 and a second current collector foil 5 are laminated on the first current collector foil 4 on which the first electrode layer 6 etc. are formed, and pressed. After that, electrode tabs etc. are connected. This gives the laminate 2. Then, a pair of films for the outer casing material 3 are placed so as to sandwich the laminate 2. Then, the pair of films are sealed while reducing the pressure between the pair of films so as to form a seal portion 15. This gives the all-solid-state battery 1.

[0041] The method for forming the frame structure 30 having an inclined outer peripheral end surface is not particularly limited. However, an example will be described with reference to Figure 7. First, a first electrode layer 6 is formed on the first current collector foil 4. Next, a liquid material (slurry) containing the substance constituting the frame structure 30 is prepared. Then, the prepared liquid material is applied in a frame shape onto the first current collector foil 4 using a dispenser having a circular nozzle and allowed to dry.

[0042] In this case, if a low-viscosity slurry is used, the outer peripheral end of the initial frame structure 30A formed immediately after application will spread, naturally resulting in a frame structure 30B with an inclined outer peripheral surface. Furthermore, the frame structure 30B can also fill the gap formed between the first electrode layer 6 and the frame structure 30. In addition, the outer peripheral end of the first electrode layer 6 can be covered by the inner peripheral end of the frame structure 30B.

[0043] On the other hand, it is also possible to use a high-viscosity slurry. In this case, as shown in Figure 7, a frame structure 30A is initially formed. In this example, the frame structure 30A is sloped so that its thickness decreases towards the inside. As a result, a gap is created between the inner circumferential end surface of the frame structure 30A and the outer circumferential end surface of the first electrode layer 6. In the subsequent pressing process, the frame structure 30A is pressurized and expands, filling the gap. This forms the final frame structure 30B. With this method, the amount of frame structure 30 can be minimized, and therefore the volume and mass of the all-solid-state battery 1 can be minimized.

[0044] When forming the frame structure 30, a frame structure 30 including rounded corners 16 as shown in Figure 2 can be obtained by applying the slurry through a circular nozzle. Furthermore, by applying the slurry through a circular nozzle having, for example, an opening radius of 0.5 mm or more, a frame structure 30 including corners 16 having a suitable curvature (curvature of 1 to 3) can be obtained.

[0045] Furthermore, by reducing the movement speed of the circular nozzle at the corner 16 during slurry application, the frame width at the corner 16 can be made larger than that of the other parts. Alternatively, the frame width at the corner 16 can be selectively widened by applying the slurry twice only at the corner 16. This makes it possible to realize a frame structure 30 having a shape like the modified example shown in Figure 4.

[0046] Next, we will explain each of the constituent materials included in the all-solid-state battery 1.

[0047] (Positive electrode layer) The positive electrode layer should be formed from a material that can release lithium ions during charging and absorb lithium ions during discharging. The positive electrode layer is formed from 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, or Si-containing compounds such as Li2FeSiO4 and Li2MnSiO4. Also, Li4Ti5O 12 Other types can also be used. The thickness of the positive electrode layer is, for example, 10 to 500 μm, preferably 50 to 200 μm.

[0048] (Negative electrode layer) The negative electrode layer can be any layer that deposits lithium during charging, or a layer that absorbs lithium during charging. For example, the negative electrode layer can be formed from a material containing a resin binder and a negative electrode active material dispersed in the resin binder. Examples of negative electrode active materials that can be used include lithium metal, silicon materials, tin materials, compounds containing silicon or tin (oxides, nitrides, alloys with other metals), and carbon materials (graphite, etc.).

[0049] Furthermore, the all-solid-state battery 1 according to this embodiment may be a so-called fully-deposited secondary battery. A fully-deposited secondary battery is a type of deposition-type secondary battery configured such that lithium metal is deposited as a negative electrode active material between the negative electrode current collector foil and the solid electrolyte layer during charging. In a fully-deposited secondary battery, all of the lithium metal as a negative electrode active material moves to the positive electrode side during complete discharge. In a fully-deposited all-solid-state battery 1, at least the negative electrode active material deposited between the negative electrode current collector foil and the solid electrolyte layer during charging can be said to be the negative electrode layer. When the all-solid-state battery 1 is a fully-deposited secondary battery, it is preferable that the first electrode layer 6 is the positive electrode layer and the second electrode layer 7 is the negative electrode layer.

[0050] In addition, in deposition-type secondary batteries, a negative electrode protective layer (sometimes called a negative electrode intermediate layer) may be provided between the solid electrolyte layer and the negative electrode current collector foil to prevent damage to the solid electrolyte layer by the highly reactive lithium metal.

[0051] (solid electrolyte layer) The solid electrolyte layer 8 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 8 can be formed from sulfides or oxides. For example, the solid electrolyte layer 8 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 8 is not particularly limited, but is, for example, 5 to 100 μm, preferably 20 to 60 μm.

[0052] (Frame structure) The frame structure 30 can be made of any insulating material. For example, the same material used to make up the solid electrolyte layer 8 can be used for the frame structure 30.

[0053] (Negative electrode current collector foil and positive electrode current collector foil) One of the first current collector foil 4 and the second current collector foil 5 is the negative electrode current collector foil, and the other is the positive electrode current collector foil. For the negative electrode current collector foil, for example, a thin film of copper, copper alloy, nickel, or nickel alloy can be used. For the positive electrode current collector foil, for example, aluminum foil can be used.

[0054] (Exterior materials) The exterior material 3 is not particularly limited, but for example, aluminum foil with an insulating layer formed on its surface can be used.

[0055] The present invention has been described above using embodiments and their modifications. Below, a typical configuration of the present invention and its effects are summarized.

[0056] In one embodiment, the all-solid-state battery 1 comprises a laminate 2 having a configuration in which at least one first electrode layer 6, at least one solid electrolyte layer 8, and at least one second electrode layer 7 are laminated in a laminate region 20, and an outer casing material 3 that houses the laminate 2. One of the first electrode layer 6 and the second electrode layer 7 is a positive electrode layer, and the other is a negative electrode layer. When viewed along the laminate direction, the first electrode layer 6 is substantially rectangular. Of the at least one first electrode layer 6, the electrode layer located on the outermost side in the laminate direction is defined as the outermost first electrode layer 9. The laminate 2 is further provided with an outermost frame structure 10, which is an insulating frame structure that surrounds the outermost first electrode layer 9 in the planar direction. The outer peripheral end faces of the outermost frame structure 10 are inclined such that the thickness of the outermost frame structure 10 decreases towards the outside. When viewed along the laminate direction, the outermost frame structure 10 is substantially rectangular. The inclination angle of the outer peripheral end face on the short side of the outermost frame structure 10 is greater than the inclination angle of the outer peripheral end face on the long side of the outermost frame structure 10. With this configuration, since the outer peripheral end face of the outermost frame structure 10 is inclined, the load applied from the exterior material 3 to the laminate 2 is distributed. Therefore, damage to the exterior material 3 and the laminate 2 can be prevented. The outermost frame structure 10 only needs to be arranged so as to surround the outermost first electrode layer 9, so the volume of the all-solid-state battery 1 does not increase. In addition, since the inclination angle of the outer peripheral end face on the short side of the outermost frame structure 10 is greater than the inclination angle of the outer peripheral end face on the long side of the outermost frame structure 10, the excess volume of the all-solid-state battery 1 can be reduced.

[0057] In one embodiment, the laminate 2 further comprises at least one first current collector foil 4 and at least one second current collector foil 5. The first electrode layer 6 is formed on the first current collector foil 4. The second electrode layer 7 is formed on the second current collector foil 5.

[0058] In one embodiment, when viewed along the stacking direction, the outermost edge of the outermost first electrode layer 9 is located inward from the outermost edge of the first current collector foil 4. The outermost frame structure 10 is placed on the first current collector foil 4. When viewed along the stacking direction, the outermost edge of the outermost frame structure 10 is located at the same position as the outermost edge of the first current collector foil 4, or is located inward from the outermost edge of the first current collector foil 4. With this configuration, since the outermost frame structure 10 does not protrude beyond the first current collector foil 4, the increase in volume and weight of the all-solid-state battery 1 can be suppressed.

[0059] In one embodiment, the laminate 2 has a configuration in which a single cell 11 is sandwiched between a first current collector foil 4 and a second current collector foil 5. The single cell 11 consists of a first electrode layer 6, a second electrode layer 7, and a solid electrolyte layer 8 sandwiched between the first electrode layer 6 and the second electrode layer 7. The laminate 2 is provided with an insulating frame structure as a battery section frame structure 12 so as to surround the battery section first electrode layer 19, which is the first electrode layer 6 included in the single cell 11, in the planar direction. The outer peripheral end surface of the battery section frame structure 12 is inclined such that the thickness of the battery section frame structure 12 decreases towards the outside. With this configuration, damage due to interference between the end of the first electrode layer 6 included in the single cell 11 and the end of the solid electrolyte layer 8 can be prevented.

[0060] In one embodiment, the first current collector foil 4 extends laterally from the lamination region 20 on the first electrode tab side, which is one side in a first direction perpendicular to the lamination direction, and is connected to the first electrode tab 13 at its end on the first electrode tab side. When viewed along the lamination direction, the outer peripheral end of the battery section frame structure 12 on the first electrode tab side in the first direction is located outside the outer peripheral end of the second current collector foil 5. With this configuration, it is possible to prevent short circuits caused by contact between the first current collector foil 4 and the second current collector foil 5.

[0061] In one embodiment, when viewed along the lamination direction, each of the four corners 16 of the outermost frame structure 10 has a rounded shape. The curvature of each corner 16 is 1 or greater. With this configuration, the load is sufficiently distributed at the corners 16 of the outermost frame structure 10, so that damage to the exterior material 3 and the laminate 2 can be prevented more reliably.

[0062] In one embodiment, when viewed along the lamination direction, the frame width of the outermost frame structure 10 is wider at the corners 16 than at the parts other than the corners 16. With this configuration, the load is sufficiently distributed at the corners 16 of the outermost frame structure 10, so that damage to the exterior material 3 and the laminate 2 can be prevented more reliably.

[0063] In one embodiment, the method for manufacturing the all-solid-state battery 1 comprises the steps of manufacturing a laminate 2 and housing the laminate 2 in an outer casing material 3. The step of manufacturing the laminate includes applying a liquid material containing the substance constituting the outermost frame structure 10 in a frame shape onto the first current collector foil 4 using a dispenser having a circular nozzle. With this configuration, by using a dispenser having a circular nozzle, the outermost frame structure 10 including rounded corners 16 can be obtained.

[0064] In one embodiment, the process of manufacturing the laminate includes the steps of forming an outermost first electrode layer 9 on a first current collector foil 4, forming an outermost frame structure 10 on the first current collector foil 4 after the step of forming the outermost first electrode layer, and pressing the outermost frame structure 10 after the step of forming the outermost frame structure 10. Before the pressing step, the inner circumferential end surface of the outermost frame structure 10 is inclined such that its thickness decreases towards the inside. During the pressing step, the gap formed between the inner circumferential end surface of the outermost frame structure 10 and the outer circumferential end surface of the outermost first electrode layer 9 is filled. By this method, the volume and mass of the all-solid-state battery 1 can be minimized.

Claims

1. A laminate having a configuration in which at least one first electrode layer, at least one solid electrolyte layer, and at least one second electrode layer are laminated in a laminated region, An exterior material that houses the laminated body, Equipped with, One of the first electrode layer and the second electrode layer is a positive electrode layer, and the other is a negative electrode layer. When viewed along the stacking direction, the first electrode layer is approximately rectangular. Of the at least one first electrode layer, the electrode layer located on the outermost side in the stacking direction is defined as the outermost first electrode layer. The laminate is further provided with an insulating frame structure as the outermost frame structure, which surrounds the outermost first electrode layer in the planar direction. The outermost end face of the outermost frame structure is inclined such that the thickness of the outermost frame structure decreases towards the outside. When viewed along the stacking direction, the outermost frame structure is approximately rectangular. The inclination angle of the outer peripheral end face on the short side of the outermost frame structure is greater than the inclination angle of the outer peripheral end face on the long side of the outermost frame structure. All-solid-state battery.

2. A solid-state battery as described in claim 1, The laminate further comprises at least one first current collector foil and at least one second current collector foil. The first electrode layer is formed on the first current collector foil, The second electrode layer is formed on the second current collector foil. All-solid-state battery.

3. A solid-state battery as described in claim 2, When viewed along the lamination direction, the outermost edge of the outermost first electrode layer is located inward from the outermost edge of the first current collector foil. The outermost frame structure is arranged on the first current collector foil, When viewed along the lamination direction, the outermost edge of the outermost frame structure is located at the same position as the outermost edge of the first current collector foil, or is located inside the outermost edge of the first current collector foil. All-solid-state battery.

4. A solid-state battery according to claim 2 or 3, The laminate has a configuration in which a single cell is sandwiched between the first current collector foil and the second current collector foil. The single cell comprises the first electrode layer, the second electrode layer, and the solid electrolyte layer sandwiched between the first electrode layer and the second electrode layer. The laminate is provided with an insulating frame structure as a battery section frame structure, so as to surround the first electrode layer contained in the single cell in the planar direction. The outer peripheral end surface of the battery frame structure is inclined such that the thickness of the battery frame structure decreases towards the outside. All-solid-state battery.

5. A solid-state battery as described in claim 4, The first current collector foil extends laterally from the laminated region on the first electrode tab side, which is one side in a first direction perpendicular to the lamination direction, and is connected to the first electrode tab at the end on the first electrode tab side. When viewed along the stacking direction, the outer peripheral end of the battery frame structure on the first electrode tab side in the first direction is located outside the outer peripheral end of the second current collector foil. All-solid-state battery.

6. A solid-state battery according to claim 1 or 2, When viewed along the stacking direction, each of the four corners of the outermost frame structure has a rounded shape, and the curvature of each corner is 1 or greater. All-solid-state battery.

7. A solid-state battery according to claim 1 or 2, When viewed along the stacking direction, the frame width of the outermost frame structure is wider at the corners than at the rest of the frame. All-solid-state battery.

8. A method for manufacturing an all-solid-state battery according to claim 1 or 2, The process of manufacturing the laminate, A step of housing the laminated body inside the exterior material, Equipped with, A method for manufacturing all-solid-state batteries.

9. A manufacturing method according to claim 8, The process for producing the laminate includes applying a liquid material containing the substance constituting the outermost frame structure to the first current collector foil in a frame shape using a dispenser having a circular nozzle. Manufacturing method.

10. A method for manufacturing an all-solid-state battery as described in Claim 2, The process of manufacturing the laminate, A step of housing the laminated body inside the exterior material, Equipped with, The process of producing the laminate is as follows: The process involves forming the outermost first electrode layer on the first current collector foil, The process of forming the outermost first electrode layer is followed by the process of forming the outermost frame structure on the first current collector foil, The process includes the step of forming the outermost frame structure followed by the step of pressing the outermost frame structure, Prior to the pressing process, the inner circumferential end surface of the outermost frame structure is inclined such that its thickness decreases towards the inside. In the pressing process, the gap formed between the inner circumferential end surface of the outermost frame structure and the outer circumferential end surface of the outermost first electrode layer is filled. Manufacturing method.

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