All-solid battery

Abstract

To suppress the occurrence of a crack of a solid electrolyte that causes short-circuiting.SOLUTION: An all-solid battery includes a solid electrolyte layer, a negative electrode layer including a negative electrode lithium metal layer stacked on one surface of the solid electrolyte layer and having lithium metal precipitated, and a positive electrode layer stacked on the other surface of the solid electrolyte layer. The solid electrolyte layer includes an electrolyte base part that forms a surface region held between the negative electrode layer and the positive electrode layer, and an outer edge part provided along the outer periphery of the electrolyte base part and extending on the outer side relative to the negative electrode lithium metal layer. In the outer edge part of the solid electrolyte layer, a surface facing the negative electrode layer is flush with or concave with respect to the electrolyte base part and is formed to protrude to the positive electrode layer side.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] In Patent Document 1, an all-solid-state battery has been proposed in which the end portion of the electrolyte layer is formed in a convex shape protruding toward the negative electrode layer side to thicken the end portion of the electrolyte layer and improve its strength.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, from the viewpoint of improving the energy density, all-solid-state batteries using metallic lithium as the negative electrode have been developed. In this type of all-solid-state battery, metallic lithium is deposited on the negative electrode during charging to form a negative electrode metallic lithium layer. On the other hand, during discharging, at least a part of the negative electrode metallic lithium layer disappears as lithium ions move to the positive electrode.

[0005] In an all-solid-state battery having such a configuration, metallic lithium may precipitate so as to extend toward the outside of the solid electrolyte, and stress concentration may occur at the contact portion between the negative electrode metallic lithium layer and the solid electrolyte due to the extension. In particular, in the structure of the all-solid-state battery proposed in Patent Document 1, the end portion of the electrolyte layer comes into contact with the end face of the negative electrode. Therefore, when this structure is applied to an all-solid-state battery using metallic lithium as the negative electrode, stress concentration occurs between the end face of the negative electrode and the end portion of the electrolyte layer as the negative electrode lithium metal extends, which may cause cracks in the solid electrolyte, leading to a short circuit.

[0006] Accordingly, an object of the present invention is to provide an all-solid-state battery capable of suppressing the occurrence of cracks in a solid electrolyte layer that causes a short circuit. **Means for Solving the Problems**

[0007] According to an aspect of the present invention, there is provided an all-solid-state battery including a solid electrolyte layer, a negative electrode layer including a negative electrode lithium metal layer in which metallic lithium is deposited and laminated on one surface of the solid electrolyte layer, and a positive electrode layer laminated on the other surface of the solid electrolyte layer. In this all-solid-state battery, the solid electrolyte layer has an electrolyte base portion constituting a surface region sandwiched between the negative electrode layer and the positive electrode layer, and an outer edge portion provided on the outer periphery of the electrolyte base portion and extending beyond the negative electrode lithium metal layer. The outer edge portion of the solid electrolyte layer is configured such that the surface facing the negative electrode layer is flush with or concave with respect to the electrolyte base portion and protrudes toward the positive electrode layer side. **Advantages of the Invention**

[0008] According to the present invention, the occurrence of cracks in the solid electrolyte layer that causes a short circuit can be suppressed. **Brief Description of the Drawings**

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

[0010] Hereinafter, each embodiment of the present invention will be described.

[0011] (First Embodiment) The all-solid-state battery 10 according to the first embodiment of the present invention will be described.

[0012] FIG. 1 is a diagram for explaining the configuration of the all-solid-state battery 10 of the present embodiment. In particular, FIG. 1(a) shows a schematic configuration of the all-solid-state battery 10 in the state of lithium metal deposition (during charging), and FIG. 1(b) shows a schematic configuration of the all-solid-state battery 10 in the state of lithium metal disappearance (during discharging). In FIG. 1, for simplicity of the drawing, only the main parts (a part of the outer peripheral region of each layer) to which the configuration of the present embodiment is applied are shown.

[0013] The all-solid-state battery 10 is configured by sealing one or a plurality of cell units 10A, each of which is a laminate in which a solid electrolyte layer 15 is laminated between a negative electrode layer n and a positive electrode layer p, with a laminate material 20. In FIG. 1, for simplicity of the drawing, an example in which the cell unit 10A is composed of a single laminate is shown. Note that the cell unit 10A is provided with electrical wirings (such as a positive electrode lead, a negative electrode lead, a positive electrode current collector plate, and a negative electrode current collector plate), not shown, for connecting to an electrical load or the like outside the laminate material 20.

[0014] The cell unit 10A of the present embodiment is formed in a substantially rectangular shape in plan view. That is, the negative electrode layer n, the positive electrode layer p, and the solid electrolyte layer 15 are each formed in a substantially rectangular shape in plan view.

[0015] The negative electrode layer n is mainly composed of a negative electrode lithium metal layer 14 laminated on the other surface (the upper surface in the drawing) of the solid electrolyte layer 15 in the lamination direction, and a negative electrode current collector 12 connected to the negative electrode lithium metal layer 14.

[0016] The negative electrode lithium metal layer 14 is mainly composed of lithium metal and functions as a negative electrode active material layer. In particular, as shown in Fig. 1(a), the negative electrode lithium metal layer 14 is formed by the precipitation of metallic lithium in the region between the solid electrolyte layer 15 and the negative electrode current collector 12 (especially the portion facing the positive electrode active material layer 17) during charging. On the other hand, as shown in Fig. 1(b), at least a part of the metallic lithium constituting the negative electrode lithium metal layer 14 disappears as lithium ions during discharging. Therefore, the thickness of the negative electrode lithium metal layer 14 during discharging decreases compared to that during charging.

[0017] In particular, in the present embodiment, the negative electrode lithium metal layer 14 is configured such that the negative electrode outer edge portion 14A constituting the outer peripheral portion in the lateral direction thereof is located inside the electrolyte outer edge portion 15B. In the present embodiment, the negative electrode outer edge portion 14A means a region along the outer periphery of the substantially rectangular negative electrode lithium metal layer 14 and facing the electrolyte outer edge portion 15B in the stacking direction.

[0018] Here, the precipitation of metallic lithium basically occurs in the region facing the positive electrode active material layer 17 between the solid electrolyte layer 15 and the negative electrode current collector 12. On the other hand, from the viewpoint of more reliably suppressing the precipitation of metallic lithium outside the positive electrode active material layer 17 on the solid electrolyte layer 15 (especially on the electrolyte outer edge portion 15B), it is preferable to limit the maximum discharge region of the all-solid-state battery 10 so that the negative electrode lithium metal layer 14 does not completely disappear. As a result, a part of the negative electrode lithium metal layer 14 remains without disappearing during discharging (see Fig. 1(b)), and thus the precipitation region of metallic lithium can be suitably adjusted to the portion of the negative electrode lithium metal layer 14.

[0019] Furthermore, instead of or together with the above-described method of adjusting the precipitation region of metallic lithium, a layer having a higher affinity for metallic lithium than the solid electrolyte layer 15 may be provided between the solid electrolyte layer 15 and the negative electrode current collector 12. In particular, by providing such a layer, the precipitation region of metallic lithium can be suitably adjusted without restricting the maximum discharge region (even in a configuration where the negative electrode lithium metal layer 14 is completely disappeared).

[0020] The positive electrode layer p is mainly composed of a positive electrode active material layer 17 laminated on one surface (the lower surface in the figure) of the solid electrolyte layer 15 in the lamination direction, and a positive electrode current collector 18 connected to the positive electrode active material layer 17. In particular, in the present embodiment, the positive electrode active material layer 17 is formed in a substantially linear shape in which the surface on the side of the solid electrolyte layer 15 of the positive electrode outer edge portion 17A constituting the outer peripheral portion in the lateral direction thereof is inclined in a direction away from the solid electrolyte layer 15 (the lower and upper directions in the figure). In the present embodiment, the positive electrode outer edge portion 17A means a region along the outer periphery of the substantially rectangular positive electrode active material layer 17 and facing the electrolyte outer edge portion 15B described later in the lamination direction.

[0021] The solid electrolyte layer 15 is mainly composed of an electrolyte base portion 15A which is a basic surface region sandwiched between the negative electrode layer n and the positive electrode layer p, and an electrolyte outer edge portion 15B which constitutes the outer periphery of the electrolyte base portion 15A, that is, the outer peripheral portion in the lateral direction of the solid electrolyte layer 15.

[0022] The electrolyte base portion 15A is a surface region in which one surface of the solid electrolyte layer 15 faces the negative electrode lithium metal layer 14 and the other surface faces the positive electrode active material layer 17. The electrolyte outer edge portion 15B is a region extending outward from the electrolyte base portion 15A in the solid electrolyte layer 15.

[0023] And the electrolyte outer edge portion 15B of the present embodiment extends beyond the negative electrode outer edge portion 14A in the negative electrode lithium metal layer 14. That is, the electrolyte base portion 15A envelopes the negative electrode outer edge portion 14A in plan view. In other words, the surface region of the negative electrode lithium metal layer 14 is configured to be within the surface region of the solid electrolyte layer 15.

[0024] Furthermore, the surface on the n-side of the negative electrode layer in the electrolyte outer edge portion 15B is configured to be flush with the electrolyte base portion 15A continuously. As a result, the electrolyte outer edge portion 15B has a structure that is completely separated without overlapping the negative electrode outer edge portion 14A in a side view. On the other hand, the surface on the p-side of the positive electrode layer in the electrolyte outer edge portion 15B of the solid electrolyte layer 15 has a structure that protrudes toward the p-side of the positive electrode layer from the electrolyte base portion 15A. As a result, the electrolyte outer edge portion 15B is configured to be thicker than the electrolyte base portion 15A. In particular, in the present embodiment, the electrolyte outer edge portion 15B protrudes toward the p-side of the positive electrode layer in the entire lateral region extending to the outside of the negative electrode lithium metal layer 14 with the electrolyte base portion 15A as a reference point. For this reason, the electrolyte outer edge portion 15B is configured to be thicker than the electrolyte base portion 15A as a whole in the lateral direction.

[0025] Next, the materials of each element (negative electrode layer n, positive electrode layer p 、 and solid electrolyte layer 15) constituting the all-solid-state battery 10 according to the present embodiment and an outline of the manufacturing method of the all-solid-state battery 10 will be described.

[0026] [Negative Electrode] As described above, the negative electrode layer n of the present embodiment includes a negative electrode current collector 12 and a negative electrode lithium metal layer 14.

[0027] The material constituting the negative electrode current collector 12 is not particularly limited as long as it functions as a current collector applicable to the all-solid-state battery 10 in the technical field to which the present invention pertains. For example, a metal or a resin having conductivity can be employed.

[0028] Specifically, examples of the metal material applicable to the negative electrode current collector 12 include aluminum, nickel, iron, stainless steel, titanium, or copper. In addition to these, a clad material of nickel and aluminum, or a clad material of copper and aluminum may be used. Furthermore, a foil in which the surface of the metal is coated with aluminum may also be used. In particular, from the viewpoints of electron conductivity, battery operating potential, and adhesion of the negative electrode active material to the current collector by sputtering, it is preferable to employ aluminum, stainless steel, copper, or nickel.

[0029] Examples of the conductive resin material applicable to the negative electrode current collector 12 include resins obtained by adding a conductive filler to a non-conductive polymer material as necessary.

[0030] In particular, examples of the non-conductive polymer material include polyethylene (PE; such as high-density polyethylene (HDPE) or low-density polyethylene (LDPE)), polypropylene (PP), polyethylene terephthalate (PET), polyether nitrile (PEN), polyimide (PI), polyamideimide (PAI), polyamide (PA), polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), polyacrylonitrile (PAN), polymethyl acrylate (PMA), polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), polyvinylidene fluoride (PVdF), or polystyrene (PS).

[0031] The negative electrode lithium metal layer 14 is formed between the solid electrolyte layer 15 and the negative electrode current collector 12 and is a layer mainly composed of single lithium metal. Note that the negative electrode lithium metal layer 14 may be configured in advance during the manufacture of the all-solid-state battery 10, or may be configured to be generated by precipitation of lithium supplied from a predetermined lithium source (such as the solid electrolyte layer 15 or the positive electrode active material layer 17) through the first charge without being provided during the manufacture.

[0032] [Positive Electrode] The positive electrode layer p is composed of a positive electrode active material layer 17 and a positive electrode current collector 18.

[0033] The positive electrode active material layer 17 is configured of an active material capable of reversibly occluding and releasing lithium ions. For example, materials applicable to the positive electrode active material layer 17 are, for example, lithium metal composite oxides. More specifically, examples of the lithium metal composite oxides include layered rock salt type compounds such as LiCoO2, LiMnO2, LiNiO2, LiVO2, or Li(Ni-Mn-Co)O2, LiMn2O4, or LiNi 0.5 Mn 1.5Examples include spinel-type compounds such as O4, olivine-type compounds such as LiFePO4 or LiMnPO4, or Si-containing compounds such as Li2FeSiO4 or Li2MnSiO4. Further, examples of lithium metal composite oxides other than those described above include, for example, Li4Ti5O 12 can be mentioned.

[0034] The positive electrode current collector 18 can be made of the same material as the negative electrode current collector 12.

[0035] [Solid electrolyte] The solid electrolyte layer 15 is a layer containing a solid electrolyte as a main component. Examples of the solid electrolyte include sulfide solid electrolytes and oxide solid electrolytes, but a sulfide solid electrolyte is preferred.

[0036] In particular, examples of the sulfide solid electrolyte include, for example, LiI-Li2S-SiS2, LiI-Li2S-P2O5, LiI-Li3PO4-P2S5, Li2S-P2S5, LiI-Li3PS4, LiI-LiBr-Li3PS4, Li3PS4, Li2S-P2S5, Li2S-P2S5-LiI, Li2S-P2S5-Li2O, Li2S-P2S5-Li2OLiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiC l , Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (However, m , n is a positive number, and Z is any one of Ge, Zn, Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, or Li2S-SiS2-Li x MO y (However, x , y is a positive number, and M is any one of P, Si, Ge, B, Al, Ga, In), etc. Note that the description of "Li2S-P2S5" means a sulfide solid electrolyte formed using a raw material composition containing Li2S and P2S5, and the same applies to other descriptions.

[0037] Further, the sulfide solid electrolyte may be a sulfide glass, a crystallized sulfide glass, or a crystalline material obtained by a solid-phase method. The sulfide glass can be obtained, for example, by performing mechanical milling (such as a ball mill) on a raw material composition.

[0038] [Manufacture of All-Solid-State Battery] The all-solid-state battery 10 according to the present embodiment can be manufactured by laminating and pressing the above positive electrode layer p, solid electrolyte layer 15, and negative electrode layer n by a known method.

[0039] [Operation and Effect] The configuration and operation and effect of the all-solid-state battery 10 of the present embodiment described above will be collectively described.

[0040] The all-solid-state battery 10 of the present embodiment includes a solid electrolyte layer 15, a negative electrode layer n including a negative electrode lithium metal layer 14 on which metallic lithium is deposited and laminated on one surface of the solid electrolyte layer 15, and a positive electrode layer p laminated on the other surface of the solid electrolyte layer 15. And this all-solid-state battery 10 has an electrolyte base portion 15A that constitutes a surface region sandwiched between the negative electrode layer n and the positive electrode layer p, and an electrolyte outer edge portion 15B as an outer edge portion provided on the outer periphery of the electrolyte base portion 15A and extending beyond the negative electrode lithium metal layer 14. And the electrolyte outer edge portion 15B is configured such that the surface facing the negative electrode layer n is flush with or concave with respect to the electrolyte base portion 15A and protrudes toward the positive electrode layer p side.

[0041] Accordingly, even in a scenario where the negative electrode lithium metal layer 14 extends outward (for example, when transitioning from the state of FIG. 1(b) to the state of FIG. 1(a)), a configuration can be realized in which the electrolyte outer edge portion 15B does not exist on the extension track of the negative electrode outer edge portion 14A. For this reason, stress transmission caused by contact between the negative electrode lithium metal layer 14 and the solid electrolyte layer 15 can be more reliably prevented. Moreover, since the electrolyte outer edge portion 15B protrudes toward the positive electrode layer p side in a shape where the outer peripheral portion of the solid electrolyte layer 15 has a certain thickness, the strength thereof is improved. That is, in the all-solid-state battery 10 of the present embodiment, by devising the structure of the electrolyte outer edge portion 15B described above, not only can the generation of stress concentration itself be suppressed by preventing the negative electrode outer edge portion 14A, which is likely to be displaced outward, from contacting the outer peripheral portion of the solid electrolyte layer 15, but also the strength of the peripheral portion of the solid electrolyte layer 15 that resists this stress concentration can be ensured even if stress concentration occurs. As a result, the occurrence of cracks in the solid electrolyte layer 15, which is a cause of short circuit, can be preferably suppressed.

[0042] In particular, in the present embodiment, the electrolyte outer edge portion 15B protrudes toward the positive electrode layer p side over the entire lateral direction region extending from the electrolyte base portion 15A to the outside of the negative electrode lithium metal layer 14.

[0043] Thereby, the strength of the outer peripheral portion of the solid electrolyte layer 15, where stress concentration is particularly likely to occur due to the precipitation of lithium metal, can be more reliably increased. As a result, the occurrence of cracks in the solid electrolyte layer 15 can be more preferably suppressed.

[0044] (Second Embodiment) Hereinafter, the all-solid-state battery 10 of the second embodiment will be described. Note that the same reference numerals are given to the same elements as in the first embodiment, and the description thereof will be omitted.

[0045] FIG. 2 is a diagram for explaining the configuration of the all-solid-state battery 10 according to the present embodiment. As shown in the figure, in the all-solid-state battery 10 of the present embodiment, the shape of the surface of the electrolyte outer edge portion 15B facing the negative electrode layer n is different from that of the all-solid-state battery 10 of the first embodiment. Specifically, the surface of the electrolyte outer edge portion 15B facing the negative electrode layer n is formed in a concave shape that gradually separates from the negative electrode lithium metal layer 14 as it goes outward from the electrolyte base portion 15A. More specifically, the surface of the electrolyte outer edge portion 15B facing the negative electrode layer n is formed in a substantially linear shape that inclines toward the positive electrode layer p side (downward in the figure) as it goes outward with the electrolyte base portion 15A as a reference point.

[0046] According to this configuration, in addition to the effects described in the first embodiment, the surface pressure acting on the solid electrolyte layer 15 (particularly, the electrolyte outer edge portion 15B) from the negative electrode lithium metal layer 14 can be further reduced. Therefore, the stress generated in the solid electrolyte layer 15 due to the stretching of the negative electrode lithium metal layer 14 is further relaxed. As a result, the effect of suppressing the generation of cracks in the solid electrolyte layer 15, which is a cause of short circuit, can be further enhanced.

[0047] (Third Embodiment) Hereinafter, the all-solid-state battery 10 of the third embodiment will be described. Note that the same reference numerals are given to the same elements as in the second embodiment, and the description thereof will be omitted.

[0048] FIG. 3 is a diagram for explaining the configuration of the all-solid-state battery 10 of the present embodiment. As shown in the figure, the all-solid-state battery 10 of the present embodiment is based on the configuration of the second embodiment, and the surfaces of the electrolyte outer edge portion 15B of the solid electrolyte layer 15 facing the positive electrode layer p and the negative electrode layer n are formed in a curved shape continuous with the electrolyte base portion 15A.

[0049] More specifically, the surface of the electrolyte outer edge portion 15B facing the negative electrode layer n is formed in a curve (particularly, a curve convex toward the negative electrode layer n) in a direction of gradually separating from the negative electrode layer n as it goes outward with the electrolyte base portion 15A as a reference point.

[0050] On one side, the surface of the electrolyte outer edge portion 15B facing the positive electrode layer p is formed in a curved shape (specifically, a curve that is concave toward the positive electrode layer p) in a direction that gradually approaches the positive electrode current collector 18 as it goes outward from the electrolyte base portion 15A as a reference point.

[0051] Also, the positive electrode outer edge portion 17A of the positive electrode active material layer 17 and the negative electrode outer edge portion 14A of the negative electrode lithium metal layer 14 are each formed in a curved shape that conforms to the surface of the opposing electrolyte outer edge portion 15B.

[0052] As described above, in the all-solid-state battery 10 of the present embodiment, the electrolyte outer edge portion 15B is formed in a continuous curved shape with respect to the electrolyte base portion 15A for the surface facing the positive electrode layer p and the surface facing the negative electrode layer n. For this reason, compared with the case where these surfaces are formed in a substantially linear shape (the case shown in FIG. 2), the bending points on the solid electrolyte layer 15 where stress concentration is likely to occur can be reduced. As a result, the occurrence of cracks in the solid electrolyte layer 15, which is a cause of short circuit, can be more reliably suppressed.

[0053] (Fourth Embodiment) Hereinafter, the all-solid-state battery 10 of the fourth embodiment will be described. Note that the same reference numerals are given to elements that are the same as those in any of the first to fourth embodiments, and the description thereof will be omitted.

[0054] FIG. 4 is a diagram for explaining the configuration of the all-solid-state battery 10 of the present embodiment. As shown in the figure, the all-solid-state battery 10 of the present embodiment is based on the configuration of the third embodiment shown in FIG. 3, while the negative electrode lithium metal layer 14 is configured to extend to the outside of the positive electrode layer p. That is, the negative electrode outer edge portion 14A extends outside the positive electrode outer edge portion 17A. In other words, the all-solid-state battery 10 of the present embodiment is configured such that the existence range of the positive electrode layer p in the plane direction is within the existence range of the negative electrode lithium metal layer 14 in the plane direction.

[0055] According to the configuration of the all-solid-state battery 10 of the present embodiment described above, since the negative electrode lithium metal layer 14 extends to the outside beyond the positive electrode layer p, at least a part of the region of the negative electrode outer edge portion 14A can be made a non-opposing region with respect to the positive electrode layer p (particularly the positive electrode outer edge portion 17A). Thereby, excessive precipitation of lithium metal due to current concentration at the negative electrode outer edge portion 14A can be suppressed, and stress concentration on the solid electrolyte layer 15 that may be caused by the precipitation can be alleviated. As a result, the occurrence of cracks in the solid electrolyte layer 15, which is a cause of short circuit, can be more reliably suppressed.

[0056] In addition, in the present embodiment, an example in which the configuration is adopted such that the negative electrode lithium metal layer 14 extends to the outside beyond the positive electrode layer p based on the configuration of the all-solid-state battery 10 according to the third embodiment has been described. However, the present invention is not limited to this, and the configuration may be adopted such that the negative electrode lithium metal layer 14 extends to the outside beyond the positive electrode layer p based on the configuration of the all-solid-state battery 10 according to the first embodiment (see FIG. 1) or the configuration of the all-solid-state battery 10 according to the second embodiment (see FIG. 2).

[0057] (Fifth Embodiment) Hereinafter, the all-solid-state battery 10 of the fifth embodiment will be described. Note that the same reference numerals are given to the same elements as those in any of the first to fourth embodiments, and the description thereof will be omitted.

[0058] FIG. 5 is a diagram for explaining the configuration of the all-solid-state battery 10 of the present embodiment. In particular, FIG. 5(a) is a schematic plan view of a main part of the all-solid-state battery 10, FIG. 5(b) is an enlarged view taken along the line A-A in FIG. 5(a), and FIG. 5(c) is an enlarged view taken along the line B-B in FIG. 5(b).

[0059] In addition, in the present embodiment, in the all-solid-state battery 10, a region where the ratio of the amount of extension to the outside with respect to the perimeter of the negative electrode lithium metal layer 14 is relatively large is referred to as a "large extension region C1". Further, a region within the electrolyte outer edge portion 15B where the ratio of the amount of extension to the outside with respect to the perimeter of the negative electrode lithium metal layer 14 is relatively small is referred to as a "small extension region C2".

[0060] Note that the large elongation region C1 can be defined as a region where the ratio of the elongation amount of the negative electrode lithium metal layer 14 before and after a charging and discharging process of a predetermined number of times exceeds a predetermined threshold value determined in advance by experiments or the like. On the other hand, the small elongation region C2 can be defined as a region where the measured value of the ratio of the elongation amount is equal to or less than the predetermined threshold value.

[0061] In particular, as shown in FIG. 5(a), the large elongation region C1 of the present embodiment is a region near the vertex of the substantially rectangular negative electrode lithium metal layer 14 (indicated by a broken-line square). On the other hand, the small elongation region C2 is a region of a portion other than near the vertex (side portion in the substantially rectangular shape) (indicated by a one-dot chain line square).

[0062] And in the small elongation region C2, the outer peripheral portion of the cell unit 10A has the structure shown in FIG. 5(b). Specifically, in the small elongation region C2, in the electrolyte outer edge portion 15B, the portion between the negative electrode outer edge portion 14A and the positive electrode outer edge portion 17A is formed in substantially the same shape as the electrolyte base portion 15A. That is, in the small elongation region C2, the electrolyte outer edge portion 15B has a structure that does not protrude toward the positive electrode layer p side in the portion between the negative electrode outer edge portion 14A and the positive electrode outer edge portion 17A.

[0063] On the other hand, in the large elongation region C1, the outer peripheral portion of the cell unit 10A has the structure shown in FIG. 5(c). Specifically, in the large elongation region C1, the negative electrode outer edge portion 14A, the electrolyte outer edge portion 15B, and the positive electrode outer edge portion 17A have the same structure as the structure described in FIG. 4. In particular, in the large elongation region C1, the electrolyte outer edge portion 15B has a structure that protrudes toward the positive electrode layer p side in the portion between the negative electrode outer edge portion 14A and the positive electrode outer edge portion 17A.

[0064] Therefore, in the all-solid-state battery 10 of the present embodiment, the amount of protrusion of the electrolyte outer edge portion 15B toward the positive electrode layer p side is configured to be larger in a region (large elongation region C1) where the ratio of the outward elongation amount to the perimeter of the negative electrode lithium metal layer 14 is relatively large than in a region (small elongation region C2) where it is relatively small. For this reason, the thickness D of the electrolyte outer edge portion 15B between the negative electrode outer edge portion 14A and the positive electrode outer edge portion 17A is configured to be larger in the large elongation region C1 (FIG. 5(c)) than in the small elongation region C2 (FIG. 5(b)).

[0065] Accordingly, while thickening a portion (large stretching region C1) where particularly strong stress concentration is assumed to occur in the electrolyte outer edge portion 15B to locally increase the strength, the other portions (small stretching regions C2) are thinned to ensure the thickness of the positive electrode active material layer 17. For this reason, while exerting the effect of suppressing the generation of cracks in the solid electrolyte layer 15, the positive electrode capacity can be maintained relatively high.

[0066] In addition, in the present embodiment, as shown in FIG. 5(b), the configuration in which the electrolyte outer edge portion 15B does not protrude toward the positive electrode layer p side in the portion between the negative electrode outer edge portion 14A and the positive electrode outer edge portion 17A in the small stretching region C2 has been described. However, the present invention is not limited to this, and a configuration may be adopted in which the electrolyte outer edge portion 15B also protrudes toward the positive electrode layer p side in the small stretching region C2, but the amount of protrusion is smaller than the amount of protrusion in the large stretching region C1.

[0067] As described above, the embodiments of the present invention have been described. However, the above embodiments merely show a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments. Further, the above embodiments can be combined as appropriate.

[0068] For example, the all-solid-state battery 10 of the present embodiment can also be configured as a laminated battery in which a plurality of laminated cell units 10A are sealed with an exterior material according to the application. Further, the appearance of the all-solid-state battery 10 of the present embodiment and the electrical connection state (electrode structure) inside are not particularly limited. The appearance of the all-solid-state battery 10 may be, for example, a rectangular flat shape, a circular or elliptical shape. Alternatively, the all-solid-state battery 10 may be configured in a cylindrical shape in which one or more cell units 10A are wound and housed. Further, either a so-called non-bipolar type (internal parallel connection type) or a bipolar type (internal series connection type) may be adopted for the electrode structure of the all-solid-state battery 10.

Explanation of Reference Numerals

[0069] 10 All-solid-state battery 14 Negative electrode lithium metal layer 14A Negative electrode outer edge portion 15 Solid electrolyte layer 15A Electrolyte base portion 15B Electrolyte outer edge portion 17 Positive electrode active material layer 17A Positive electrode outer edge portion n Negative electrode layer p Positive electrode layer

Claims

1. An all-solid-state battery including: a solid electrolyte layer; an anode layer including an anode lithium metal layer laminated on one surface of the solid electrolyte layer and having metallic lithium deposited thereon; and a cathode layer laminated on the other surface of the solid electrolyte layer, the solid electrolyte layer has an electrolyte base that constitutes a surface area sandwiched between the negative electrode layer and the positive electrode layer, and an outer edge that is provided on an outer periphery of the electrolyte base and extends outward beyond the negative electrode lithium metal layer, The outer edge of the solid electrolyte layer is The surface facing the negative electrode layer is flush with or concave with the electrolyte base, and is configured to protrude toward the positive electrode layer. All-solid-state battery.

2. The all-solid-state battery according to claim 1 , The outer edge of the solid electrolyte layer is The electrolyte base protrudes toward the positive electrode layer over the entire lateral area extending from the electrolyte base to the outside of the negative electrode lithium metal layer. All-solid-state battery.

3. The all-solid-state battery according to claim 1 or 2, The outer edge of the solid electrolyte layer is The surface facing the negative electrode layer is formed in a concave shape that is spaced apart from the negative electrode lithium metal layer as it extends from the electrolyte base to the outside. All-solid-state battery.

4. The all-solid-state battery according to claim 3, The outer edge of the solid electrolyte layer is a surface facing the positive electrode layer and a surface facing the negative electrode layer are formed in a curved shape continuous with the electrolyte base; All-solid-state battery.

5. The all-solid-state battery according to any one of claims 1 to 4, The negative electrode lithium metal layer extends outward beyond the positive electrode layer. All-solid-state battery.

6. The all-solid-state battery according to any one of claims 1 to 5, The amount of protrusion of the outer edge of the solid electrolyte layer toward the positive electrode layer is In a region where the ratio of the outward extension amount to the perimeter of the negative electrode lithium metal layer is relatively large, the ratio is larger than in a region where the ratio is relatively small. All-solid-state battery.

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