All-solid-state 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 technology]

[0002] Patent Document 1 proposes an all-solid-state battery in which the end of the electrolyte layer is formed in a convex shape that protrudes toward the negative electrode layer, thereby thickening the end of the electrolyte layer and improving its strength. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6608188 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, all-solid-state batteries using metallic lithium as the anode have been developed to improve energy density. In these types of all-solid-state batteries, metallic lithium is deposited on the anode during charging, forming a metallic lithium anode layer. On the other hand, during discharging, lithium ions migrate to the cathode, causing at least a portion of the metallic lithium anode layer to disappear.

[0005] In an all-solid-state battery with such a configuration, metallic lithium is deposited so as to extend outward from the solid electrolyte, and this extension can cause stress concentration at the contact portion between the negative electrode metallic lithium layer and the solid electrolyte. In particular, in the structure of the all-solid-state battery proposed in Patent Document 1, the edge 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 in the negative electrode, stress concentration occurs between the end face of the negative electrode and the edge of the electrolyte layer as the negative electrode lithium metal extends, which may lead to cracks in the solid electrolyte that may cause a short circuit.

[0006] Therefore, an object of the present invention is to provide an all-solid-state battery that can suppress the occurrence of cracks in the solid electrolyte layer, which are a cause of short circuits. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided an all-solid-state battery including a solid electrolyte layer, an anode layer including an anode lithium metal layer on one side of the solid electrolyte layer and having metallic lithium deposited thereon, and a cathode layer on the other side of the solid electrolyte layer. In this all-solid-state battery, the solid electrolyte layer has an electrolyte base portion constituting a surface area sandwiched between the anode layer and the cathode layer, and an outer edge portion provided on the outer periphery of the electrolyte base portion and extending beyond the anode lithium metal layer. The outer edge portion of the solid electrolyte layer has a surface facing the anode layer that is adjacent to the electrolyte base portion. The negative electrode is formed in a concave shape that is spaced apart from the negative electrode lithium metal layer as it extends outward from the negative electrode. In addition, it is configured to protrude toward the positive electrode layer side. [Effects of the Invention]

[0008] According to the present invention, it is possible to suppress the occurrence of cracks in the solid electrolyte layer, which can cause short circuits. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating the configuration of an all-solid-state battery according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a diagram illustrating the configuration of the all-solid-state battery according to the second embodiment. [Figure 3] FIG. 3 is a diagram illustrating the configuration of an all-solid-state battery according to a third embodiment. [Figure 4] FIG. 4 is a diagram illustrating the configuration of an all-solid-state battery according to the fourth embodiment. [Figure 5] FIG. 5 is a diagram illustrating the configuration of an all-solid-state battery according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

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

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

[0012] Fig. 1 is a diagram illustrating the configuration of an all-solid-state battery 10 according to this embodiment. In particular, Fig. 1(a) shows a schematic configuration of the all-solid-state battery 10 in a state where metallic lithium is deposited (during charging), and Fig. 1(b) shows a schematic configuration of the all-solid-state battery 10 in a state where metallic lithium has disappeared (during discharging). Note that, in Fig. 1, for the sake of simplicity, only the main parts (parts of the outer peripheral regions of each layer) to which the configuration of this embodiment is applied are shown.

[0013] The all-solid-state battery 10 is constructed by sealing a cell unit 10A, which is formed by laminating one or more laminates, each of which has a solid electrolyte layer 15 laminated between an anode layer n and a cathode layer p, with a laminate material 20. For simplicity of illustration, FIG. 1 shows an example in which the cell unit 10A is formed of a single laminate. This cell unit 10A is provided with electrical wiring (such as a positive electrode lead, a negative electrode lead, a positive electrode current collector, and a negative electrode current collector) not shown for connecting the cell unit 10A to an external electrical load or the like outside the laminate material 20.

[0014] The cell unit 10A of this embodiment is formed in a generally 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 generally rectangular shape in plan view.

[0015] The negative electrode layer n is mainly composed of a negative electrode lithium metal layer 14 stacked on the other surface (the upper surface in the figure) of the solid electrolyte layer 15 in the stacking 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 a layer that is mainly composed of lithium metal and functions as a negative electrode active material. In particular, as shown in FIG. 1(a), the negative electrode lithium metal layer 14 is formed by the deposition of metallic lithium in the region between the solid electrolyte layer 15 and the negative electrode current collector 12 (particularly, 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 portion of the metallic lithium constituting the negative electrode lithium metal layer 14 becomes lithium ions and disappears during discharging. Therefore, the thickness of the negative electrode lithium metal layer 14 during discharging is reduced compared to during charging.

[0017] In particular, in this embodiment, negative electrode lithium metal layer 14 is configured such that negative electrode outer edge portion 14A, which forms the outer periphery of negative electrode lithium metal layer 14 in the lateral direction, is located inside electrolyte outer edge portion 15B. Note that, in this embodiment, negative electrode outer edge portion 14A refers to a region along the periphery of substantially rectangular negative electrode lithium metal layer 14 and a region facing electrolyte outer edge portion 15B in the stacking direction.

[0018] Here, deposition of metallic lithium basically occurs in a region facing positive electrode active material layer 17 between solid electrolyte layer 15 and negative electrode current collector 12. On the other hand, from the viewpoint of more reliably suppressing deposition of metallic lithium outside positive electrode active material layer 17 on solid electrolyte layer 15 (particularly on electrolyte outer edge portion 15B), it is preferable to limit the maximum discharge region of all-solid-state battery 10 to an extent that negative electrode lithium metal layer 14 does not completely disappear. This allows a portion of negative electrode lithium metal layer 14 to remain without disappearing during discharge (see FIG. 1(b)), and therefore the deposition region of metallic lithium can be suitably adjusted to this portion of negative electrode lithium metal layer 14.

[0019] Furthermore, instead of or in addition to the above-described method for adjusting the deposition region of metallic lithium, a layer having a higher affinity for metallic lithium than solid electrolyte layer 15 may be provided between solid electrolyte layer 15 and negative electrode current collector 12. In particular, by providing such a layer, the deposition region of metallic lithium can be suitably adjusted without imposing any restrictions on the maximum discharge region (even in a configuration in which negative electrode lithium metal layer 14 is completely eliminated).

[0020] The positive electrode layer p is mainly composed of a positive electrode active material layer 17 laminated on one surface (the upper or 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 this embodiment, the positive electrode active material layer 17 has a surface on the solid electrolyte layer 15 side of a positive electrode outer edge portion 17A constituting the outer periphery in the lateral direction, which is formed in a substantially linear shape that slopes in a direction away from the solid electrolyte layer 15 (the upper or lower surface in the figure). Note that in this embodiment, the positive electrode outer edge portion 17A refers to a region along the periphery of the substantially rectangular positive electrode active material layer 17 and a region facing an electrolyte outer edge portion 15B described below in the lamination direction.

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

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

[0023] In this embodiment, electrolyte outer edge portion 15B extends outward beyond negative electrode outer edge portion 14A of negative electrode lithium metal layer 14. That is, electrolyte base portion 15A envelops negative electrode outer edge portion 14A in a plan view. In other words, the surface area of ​​negative electrode lithium metal layer 14 is contained within the surface area of ​​solid electrolyte layer 15.

[0024] Furthermore, the surface of the electrolyte outer edge portion 15B on the anode layer n side is configured to be continuous with and flush with the electrolyte base portion 15A. As a result, the electrolyte outer edge portion 15B is configured to be completely separated from the anode outer edge portion 14A without overlapping it in a side view. On the other hand, the surface of the electrolyte outer edge portion 15B of the solid electrolyte layer 15 on the cathode layer p side is configured to protrude toward the cathode layer p side beyond the electrolyte base 15A. As a result, the electrolyte outer edge portion 15B is configured to be thicker than the electrolyte base 15A. In particular, in this embodiment, the electrolyte outer edge portion 15B protrudes toward the cathode layer p side in the entire lateral region extending from the electrolyte base 15A as a base point to the outside of the anode lithium metal layer 14. As a result, the electrolyte outer edge portion 15B is configured to be thicker than the electrolyte base 15A in the lateral direction overall.

[0025] Next, the materials of the elements (negative electrode layer n, positive electrode layer p, and solid electrolyte layer 15) that constitute the all-solid-state battery 10 according to this embodiment and an outline of a method for manufacturing the all-solid-state battery 10 will be described.

[0026] [Negative electrode] As described above, the negative electrode layer n of this embodiment includes the negative electrode current collector 12 and the 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 related to the present invention. For example, a metal or a conductive resin can be used.

[0028] Specifically, examples of metal materials that can be used for the negative electrode current collector 12 include aluminum, nickel, iron, stainless steel, titanium, and copper. Other materials that can be used include clad materials of nickel and aluminum, and clad materials of copper and aluminum. Furthermore, foils in which aluminum is coated on a metal surface may also be used. In particular, from the viewpoints of electronic conductivity, battery operating potential, and adhesion of the negative electrode active material to the current collector by sputtering, it is preferable to use aluminum, stainless steel, copper, or nickel.

[0029] Examples of conductive resin materials that can be used for the negative electrode current collector 12 include resins in which a conductive filler is added to a non-conductive polymer material as needed.

[0030] In particular, examples of non-conductive polymer materials include polyethylene (PE; high density polyethylene (HDPE) or low density polyethylene (LDPE)), polypropylene (PP), polyethylene terephthalate (PET), polyethernitrile (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), and polystyrene (PS).

[0031] Negative electrode lithium metal layer 14 is formed between solid electrolyte layer 15 and negative electrode current collector 12, and is a layer containing elemental lithium metal as a main component. Negative electrode lithium metal layer 14 may be formed in advance during the manufacture of all-solid-state battery 10, or may be formed by precipitation of lithium supplied from a predetermined lithium source (such as solid electrolyte layer 15 or positive electrode active material layer 17) after initial charging 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 as an active material capable of reversibly absorbing and releasing lithium ions. For example, a material applicable to the positive electrode active material layer 17 is, for example, a lithium metal composite oxide. More specifically, the lithium metal composite oxide may be a layered rock salt compound such as LiCoO2, LiMnO2, LiNiO2, LiVO2, or Li(Ni-Mn-Co)O2, LiMn2O4, or LiNi 0.5 Mn 1.5Examples of lithium metal composite oxides include spinel-type compounds such as LiFePO4 and LiMnPO4, olivine-type compounds such as LiFeSiO4 and LiMnSiO4, and Si-containing compounds such as LiFeSiO4 and LiMnSiO4. 12 Examples include:

[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, with sulfide solid electrolytes being preferred.

[0036] In particular, examples of sulfide solid electrolytes include 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, and 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 Ge, Zn, or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, or Li2S-SiS2-Li x MO y (however, x , y is a positive number, and M is any of P, Si, Ge, B, Al, Ga, and In. The term "LiS-P2S5" refers to a sulfide solid electrolyte obtained using a raw material composition containing LiS and P2S5, and the same applies to other terms.

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

[0038] [Manufacturing all-solid-state batteries] The all-solid-state battery 10 according to this embodiment can be manufactured by laminating the above-mentioned positive electrode layer p, solid electrolyte layer 15, and negative electrode layer n by a known method and applying pressure.

[0039] [Action and effect] The configuration and effects of the all-solid-state battery 10 of this embodiment described above will be described together.

[0040] The all-solid-state battery 10 of this embodiment includes a solid electrolyte layer 15, an anode layer n including an anode lithium metal layer 14 on one surface of the solid electrolyte layer 15 and having metallic lithium deposited thereon, and a cathode layer p on the other surface of the solid electrolyte layer 15. The all-solid-state battery 10 also includes an electrolyte base 15A constituting a surface region sandwiched between the anode layer n and the cathode layer p, and an electrolyte outer edge portion 15B as an outer edge portion provided on the outer periphery of the electrolyte base 15A and extending outward beyond the anode lithium metal layer 14. The surface of the electrolyte outer edge portion 15B facing the anode layer n is flush with or concave with the electrolyte base 15A and is configured to protrude toward the cathode layer p.

[0041] This allows for a configuration in which the electrolyte outer edge portion 15B is not present on the extension path of the anode outer edge portion 14A, even when the anode lithium metal layer 14 extends outward (e.g., when transitioning from the state shown in FIG. 1(b) to the state shown in FIG. 1(a)). This more reliably prevents stress transmission due to contact between the anode lithium metal layer 14 and the solid electrolyte layer 15. Furthermore, the shape of the electrolyte outer edge portion 15B protruding toward the cathode layer p ensures a sufficient thickness at the outer periphery of the solid electrolyte layer 15, thereby improving its strength. That is, in the all-solid-state battery 10 of this embodiment, the aforementioned ingenuity in the structure of the electrolyte outer edge portion 15B prevents the anode outer edge portion 14A, which is prone to outward displacement, from contacting the outer periphery of the solid electrolyte layer 15. This not only prevents stress concentration from occurring, but also ensures the strength of the peripheral portion of the solid electrolyte layer 15 to resist stress concentration even if it does occur. As a result, cracks in the solid electrolyte layer 15, which could cause a short circuit, can be effectively prevented.

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

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

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

[0045] 2 is a diagram illustrating the configuration of an all-solid-state battery 10 according to this embodiment. As shown in the figure, in the all-solid-state battery 10 of this embodiment, the shape of the surface of the electrolyte outer peripheral 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 peripheral portion 15B facing the negative electrode layer n is formed in a concave shape that gradually becomes more spaced from the negative electrode lithium metal layer 14 as it extends outward from the electrolyte base 15A. More specifically, the surface of the electrolyte outer peripheral portion 15B facing the negative electrode layer n is formed in a substantially linear shape that slopes from the electrolyte base 15A toward the positive electrode layer p side (top and bottom in the figure) as it extends outward.

[0046] According to this configuration, in addition to the effects described in the first embodiment, the surface pressure acting from anode lithium metal layer 14 to solid electrolyte layer 15 (particularly, electrolyte outer edge portion 15B) can be further reduced. This further alleviates the stress generated in solid electrolyte layer 15 due to the extension of anode lithium metal layer 14. As a result, the effect of suppressing the occurrence of cracks in solid electrolyte layer 15, which can cause short circuits, can be further improved.

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

[0048] 3 is a diagram illustrating the configuration of the all-solid-state battery 10 of this embodiment. As shown in the figure, the all-solid-state battery 10 of this embodiment is based on the configuration of the second embodiment, and the surface of the electrolyte outer edge portion 15B of the solid electrolyte layer 15 facing the positive electrode layer p and the surface facing the negative electrode layer n are formed in a curved shape that is 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 curved shape (particularly, a curved shape that is convex toward the negative electrode layer n) that gradually moves away from the negative electrode layer n as it extends outward from the electrolyte base portion 15A.

[0050] On the other hand, the surface of the electrolyte outer edge portion 15B facing the positive electrode layer p is formed in a curved shape (particularly, a curved shape that is concave toward the positive electrode layer p) that gradually approaches the positive electrode current collector 18 as it moves outward from the electrolyte base portion 15A as a base point.

[0051] Additionally, positive electrode outer edge portion 17A of positive electrode active material layer 17 and negative electrode outer edge portion 14A of negative electrode lithium metal layer 14 are also formed in curved shapes that fit the surfaces of opposing electrolyte outer edge portion 15B.

[0052] As described above, in the all-solid-state battery 10 of this embodiment, the electrolyte outer edge portion 15B has a curved shape in which the surface facing the positive electrode layer p and the surface facing the negative electrode layer n are continuous with the electrolyte base portion 15A. Therefore, compared to when these surfaces are formed in a substantially straight line (as shown in FIG. 2), it is possible to reduce bending points on the solid electrolyte layer 15 where stress concentration is likely to occur. As a result, it is possible to more reliably suppress the occurrence of cracks in the solid electrolyte layer 15, which can cause short circuits.

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

[0054] 4 is a diagram illustrating the configuration of an all-solid-state battery 10 of this embodiment. As shown in the figure, the all-solid-state battery 10 of this embodiment is based on the configuration of the third embodiment shown in FIG. 3, but is configured such that the anode lithium metal layer 14 extends outward beyond the positive electrode layer p. That is, the anode outer edge portion 14A extends outward beyond the positive electrode outer edge portion 17A. In other words, the all-solid-state battery 10 of this embodiment is configured such that the extent of the positive electrode layer p in the planar direction is within the extent of the anode lithium metal layer 14 in the planar direction.

[0055] According to the configuration of the all-solid-state battery 10 of this embodiment described above, the anode lithium metal layer 14 extends outward beyond the positive electrode layer p, so that at least a portion of the anode outer edge portion 14A can be made to be a region not facing the positive electrode layer p (particularly the positive electrode outer edge portion 17A). This makes it possible to suppress excessive deposition of lithium metal due to current concentration in the anode outer edge portion 14A, and to alleviate stress concentration on the solid electrolyte layer 15 that may be caused by such deposition. As a result, it is possible to more reliably suppress the occurrence of cracks in the solid electrolyte layer 15, which may cause short circuits.

[0056] In the present embodiment, an example has been described in which a configuration is adopted in which the anode lithium metal layer 14 extends outward beyond the positive electrode layer p, based on the configuration of the all-solid-state battery 10 according to the third embodiment. However, the present invention is not limited to this, and a configuration in which the anode lithium metal layer 14 extends outward beyond the positive electrode layer p may be adopted in which 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) is used as a base.

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

[0058] Fig. 5 is a diagram illustrating the configuration of the all-solid-state battery 10 of this 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 AA in Fig. 5(a), and Fig. 5(c) is an enlarged view taken along the line BB in Fig. 5(b).

[0059] In this embodiment, in all-solid-state battery 10, a region where the ratio of the amount of outward extension to the circumferential length of negative-electrode lithium metal layer 14 is relatively large is referred to as a "largely extended region C1." Furthermore, a region in electrolyte outer peripheral portion 15B where the ratio of the amount of outward extension to the circumferential length of negative-electrode lithium metal layer 14 is relatively small is referred to as a "smallly extended region C2."

[0060] The large stretch region C1 can be defined as a region where the ratio of the stretch amounts of the negative-electrode lithium metal layer 14 before and after a predetermined number of charge-discharge cycles exceeds a predetermined threshold value determined in advance by experiments, etc. On the other hand, the small stretch region C2 can be defined as a region where the measured value of the ratio of the stretch amounts is equal to or less than the predetermined threshold value.

[0061] 5(a), the large stretched region C1 in this embodiment is a region (indicated by a dashed square) near the vertices of the substantially rectangular negative-electrode lithium metal layer 14. On the other hand, the small stretched region C2 is a region (indicated by a dashed square) other than the vertices (side portions of the substantially rectangular shape).

[0062] 5(b) 。 Specifically, in the small stretched region C2, the portion of the electrolyte outer edge 15B between the negative electrode outer edge 14A and the positive electrode outer edge 17A is formed to have substantially the same shape as the electrolyte base 15A. That is, in the small stretched region C2, the portion of the electrolyte outer edge 15B between the negative electrode outer edge 14A and the positive electrode outer edge 17A does not protrude toward the positive electrode layer p.

[0063] On the other hand, in the large stretched region C1, the outer peripheral portion of the cell unit 10A has the structure shown in Fig. 5(c). Specifically, in the large stretched 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 structures as those described in Fig. 4. In particular, in the large stretched region C1, the electrolyte outer edge portion 15B has a structure that protrudes toward the positive electrode layer p 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 this embodiment, the amount of protrusion of the electrolyte outer peripheral portion 15B toward the positive electrode layer p is configured to be larger in a region (large stretched region C1) where the ratio of the outward stretch amount to the circumferential length of the negative electrode lithium metal layer 14 is relatively large compared to a region (small stretched region C2) where the ratio is relatively small. Therefore, the thickness D of the electrolyte outer peripheral portion 15B between the negative electrode outer peripheral portion 14A and the positive electrode outer peripheral portion 17A is configured to be larger in the large stretched region C1 (FIG. 5(c)) than in the small stretched region C2 (FIG. 5(b)).

[0065] This allows the thickness of the electrolyte outer peripheral portion 15B to be increased in a portion (largely stretched region C1) where particularly strong stress concentration is expected to occur, thereby locally increasing strength, while the other portion (smallly stretched region C2) is thinned, thereby ensuring the thickness of the positive electrode active material layer 17. This makes it possible to suppress the occurrence of cracks in the solid electrolyte layer 15, while maintaining a relatively high positive electrode capacity.

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

[0067] 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 the technical scope of the present invention is not intended to be limited to the specific configurations of the above embodiments. Furthermore, the above embodiments can be combined as appropriate.

[0068] For example, the all-solid-state battery 10 of this embodiment can be configured as a stacked battery in which a plurality of stacked cell units 10A are sealed with an exterior material, depending on the application. Furthermore, the appearance and internal electrical connection state (electrode structure) of the all-solid-state battery 10 of this embodiment are not particularly limited. The appearance of the all-solid-state battery 10 may be, for example, a flattened rectangular shape, or a circular or elliptical shape. Alternatively, the all-solid-state battery 10 may be configured as a cylindrical type that accommodates one or more wound cell units 10A. Furthermore, the electrode structure of the all-solid-state battery 10 may be either a so-called non-bipolar type (internal parallel connection type) or a bipolar type (internal series connection type). [Explanation of symbols]

[0069] 10 All-solid-state battery 14. Negative electrode lithium metal layer 14A Negative electrode outer edge 15 Solid electrolyte layer 15A electrolyte base 15B Electrolyte Outer Edge 17 Cathode active material layer 17A Positive electrode outer edge 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 portion that forms a surface area sandwiched between the negative electrode layer and the positive electrode layer, and an outer edge portion that is provided on the outer periphery of the electrolyte base portion and extends outward beyond the negative electrode lithium metal layer, The outer edge of the solid electrolyte layer is a surface facing the negative electrode layer is formed in a concave shape that moves away from the negative electrode lithium metal layer as it extends outward from 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 portion protrudes toward the positive electrode layer over the entire lateral area extending from the electrolyte base portion to the outside of the negative electrode lithium metal layer; All-solid-state battery.

3. The all-solid-state battery according to claim 1, The outer edge of the solid electrolyte layer is a surface facing the positive electrode layer and a surface facing the negative electrode layer each having a curved shape that is continuous with the electrolyte base; All-solid-state battery.

4. The all-solid-state battery according to any one of claims 1 to 3, The negative electrode lithium metal layer extends further outward than the positive electrode layer. All-solid-state battery.

5. The all-solid-state battery according to any one of claims 1 to 4, a large stretched region and a small stretched region formed on the outer periphery of the substantially rectangular negative electrode lithium metal layer; the large stretched region is a region near a vertex of the substantially rectangular negative electrode lithium metal layer, The small stretching region is a region other than the vicinity of the apex, The outer edge of the solid electrolyte layer is protruding toward the positive electrode layer in the large stretching region and the small stretching region, a thickness of an outer edge portion of the solid electrolyte layer in the large stretched region is greater than a thickness of an outer edge portion of the solid electrolyte layer in the small stretched region; All-solid-state battery.

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