All-solid-state batteries

Abstract

To provide an all-solid battery capable of suppressing reduction in capacity.SOLUTION: An all-solid battery 1 comprises: a power generation element 30 in which a negative electrode layer 33, a solid electrolyte layer 32, and a positive electrode layer 31 are sequentially laminated; an elastic body 40 that covers an outer periphery of the power generation element 30; a negative electrode current collector 20 in contact with the negative electrode layer 33; and a positive electrode current collector 10 in contact with the positive electrode layer 31. The solid electrolyte layer 32 covers a surface of the positive electrode layer 31 formed on the positive electrode current collector 10. In a cross-sectional view, a first contact point P1 is located inside a second contact point P2, the first contact point P1 being located innermost among contact points of the elastic body 40 with an outer peripheral part of the solid electrolyte layer 32 at the negative electrode layer 33 side, the second contact point P2 being located outermost among contact points between the positive electrode current collector 10 and the positive electrode layer 31.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] An all-solid-state battery is known in which a positive electrode current collector, a positive electrode powder layer, a solid electrolyte layer, a negative electrode powder layer, and a negative electrode current collector are stacked in this order (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018-110688 Summary of the Invention [Problem to be solved by the invention]

[0004] In an all-solid-state battery in which an alkali metal such as lithium is deposited on the negative electrode during charging, the alkali metal may be deposited outside the region of the negative electrode that faces the positive electrode active material layer, resulting in a problem of a decrease in the capacity of the all-solid-state battery.

[0005] The problem to be solved by the present invention is to provide an all-solid-state battery capable of suppressing a decrease in capacity. [Means for solving the problem]

[0006] The present invention solves the above problem by covering the outer periphery of the power generating element with an elastic body, and positioning, in a cross-sectional view, a first contact point, which is the innermost of the contact points between the elastic body and the outer periphery on the negative electrode layer side of the solid electrolyte, more inside than a second contact point, which is the outermost of the contact points between the positive electrode current collector and the positive electrode layer. [Effects of the Invention]

[0007] According to the present invention, it is possible to suppress the deposition of alkali metal outside the facing region, and therefore it is possible to suppress a decrease in the capacity of the all-solid-state battery. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1(a) is a cross-sectional view showing an example of a fully discharged state of the all-solid-state battery according to the first embodiment of the present invention, and FIG. 1(b) is a cross-sectional view showing an example of a charged state of the all-solid-state battery according to the first embodiment of the present invention. [Figure 2] 2(a) is an enlarged cross-sectional view of the II-A portion of FIG. 1(a), and FIG. 2(b) is an enlarged cross-sectional view of the II-B portion of FIG. 1(b). [Figure 3] 3(a) to 3(c) are cross-sectional views showing examples of first to third modified examples of the solid electrolyte layer in the embodiment of the present invention. [Figure 4] FIG. 4(a) is a cross-sectional view showing an example of a fully discharged state of the all-solid-state battery according to the second embodiment of the present invention, and FIG. 4(b) is a cross-sectional view showing an example of a charged state of the all-solid-state battery according to the second embodiment of the present invention. [Figure 5] FIG. 5 is an enlarged cross-sectional view of part V in FIG. 4(b). DETAILED DESCRIPTION OF THE INVENTION

[0009] First Embodiment A first embodiment of an all-solid-state battery 1 according to the present invention will be described with reference to the drawings. Fig. 1(a) is a cross-sectional view showing an example of a fully discharged state of an all-solid-state battery according to the first embodiment of the present invention, and Fig. 1(b) is a cross-sectional view showing an example of a charged state of an all-solid-state battery according to the first embodiment of the present invention. Fig. 2(a) is an enlarged cross-sectional view of part II-A in Fig. 1(a), and Fig. 2(b) is an enlarged cross-sectional view of part II-B in Fig. 1(b).

[0010] The fully discharged state means a state in which the SOC (State of Charge) of the all-solid-state battery 1 is 0%, and the charged state means a state in which the SOC is greater than 0%. 1(a) and 1(b) show cross sections of the all-solid-state battery 1 cut along the stacking direction.

[0011] 1(a), the all-solid-state battery 1 in a fully discharged state includes a positive electrode current collector 10, a negative electrode current collector 20, a power generating element 30 interposed therebetween, and an elastic body 40 covering the power generating element 30. Note that although FIGS. 1(a) and 1(b) illustrate only a pair of positive and negative electrode current collectors 10, 20 and the vicinity of the power generating element 30, the all-solid-state battery 1 may include a plurality of positive and negative electrode current collectors 10, 20 sandwiching the power generating element 30 therebetween.

[0012] The positive electrode current collector 10 is a conductive plate-like (or foil-like) member and is made of, for example, a metal or a conductive resin, although it is not particularly limited thereto. Examples of metals that can be used include aluminum, nickel, iron, stainless steel, titanium, and copper. Alternatively, a clad material of nickel and aluminum, or a clad material of copper and aluminum may be used. Examples of conductive resins include resins in which a conductive filler is added to a non-conductive polymer material.

[0013] The negative electrode current collector 20 is a conductive plate-like (or foil-like) member, similar to the positive electrode current collector 10, and is not particularly limited, but is made of, for example, a metal or a conductive resin. As the metal and the conductive resin, the same materials as those constituting the positive electrode current collector 10 described above can be used.

[0014] A power generating element 30 is interposed between the positive electrode current collector 10 and the negative electrode current collector 20. As shown in Fig. 1(a), this power generating element 30 has a positive electrode layer 31 and a solid electrolyte layer 32 when the all-solid-state battery 1 is in a fully discharged state.

[0015] The positive electrode layer 31 is formed on a main surface of the positive electrode current collector 10. This positive electrode layer 31 contains at least a positive electrode active material capable of absorbing and releasing an alkali metal such as lithium (Li), sodium (Na), or potassium (K), and is not particularly limited, but preferably contains a positive electrode active material containing sulfur. The sulfur-containing positive electrode active material may be a material that utilizes a sulfur oxidation-reduction reaction to release alkali metal ions such as lithium ions during charging and to absorb the alkali metal ions during discharging. The type of sulfur-containing positive electrode active material is not particularly limited, but particles or thin films of elemental sulfur (S), an organic sulfur compound, or an inorganic sulfur compound can be used.

[0016] The organic sulfur compound is not particularly limited, but examples thereof include disulfide compounds, sulfur-modified polyacrylonitrile, sulfur-modified polyisoprene, rubeanic acid (dithiooxamide), and polycarbon sulfide. The inorganic sulfur compound is not particularly limited, but examples thereof include S-carbon composite, TiS2, TiS3, TiS4, NiS, NiS2, CuS, FeS2, Li2S, MoS2, and MoS3. Note that a sulfur-free positive electrode active material may also be used.

[0017] 1(a), the positive electrode layer 31 has a trapezoidal shape. The positive electrode layer 31 has a first main surface 311, a second main surface 312 facing the first main surface, and a first side surface 313 interposed between the first and second main surfaces 311, 312.

[0018] The first main surface 311 is in contact with the positive electrode current collector 10, while the second main surface 312 and the first side surface 313 are in contact with the solid electrolyte layer 32. That is, in this embodiment, the positive electrode layer 31 formed on the positive electrode current collector 10 is embedded in the solid electrolyte layer 32, and the second main surface 312 and the first side surface 313 are covered by the solid electrolyte layer 32.

[0019] The width of the first main surface 311 is larger than the width of the second main surface 312, and as a result, as shown in Fig. 2(a), the first side surface 313 is inclined so as to approach the center of the positive electrode layer 31 as it approaches the second main surface 312. In other words, the positive electrode layer 31 has a shape that gradually narrows as it approaches the negative electrode current collector 20.

[0020] A solid electrolyte layer 32 is interposed between the positive electrode layer 31 and the negative electrode current collector 20. As shown in FIG. 1(a), when the all-solid-state battery 1 is in a fully discharged state, the solid electrolyte layer 32 is in contact with the negative electrode current collector 20. As the solid electrolyte, for example, a sulfide solid electrolyte or an oxide solid electrolyte can be used, but it is preferable to use a sulfide solid electrolyte.

[0021] 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-Li2O-LiI, Li2S-SiS2, and Li2S -SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-ZmSn (where m and n are positive numbers, and Z is Ge, Zn, or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li x MO y (where x and y are positive numbers, and M is any of P, Si, Ge, B, Al, Ga, and In). The term "Li2S-P2S5" refers to a sulfide solid electrolyte obtained using a raw material composition containing Li2S and P2S5, and the same applies to the other terms above. Alternatively, sulfide glass or the like may be used as the sulfide solid electrolyte.

[0022] As the oxide solid electrolyte, for example, a compound having a NASICON structure can be used. Examples of the compound having a NASICON structure include compounds represented by the general formula Li 1+x Al x Ge 2-x Compounds (LAGP) represented by (PO4)3 (0≦x≦2), general formula Li 1+x Al x Ti 2-x A compound (LATP) represented by (PO4)3 (0≦x≦2) can be used. Other oxide solid electrolytes include LiLaTiO (for example, Li 0.34 La 0.51 TiO3), LiPON (e.g., Li 2.9 PO 3.3 N 0.46 ), LiLaZrO (e.g., Li7La3Zr2O 12 ) etc. can be used.

[0023] The solid electrolyte layer 32 is disposed along the positive electrode current collector 10 and the second main surface 312 and first side surface 313 of the positive electrode layer 31. The solid electrolyte layer 32 has a third main surface 321 in contact with the positive electrode current collector 10, the second main surface 312, and the first side surface 313. The solid electrolyte layer 32 also has a fourth main surface 322 in contact with the negative electrode current collector 20, and a second side surface 323 interposed between the third and fourth main surfaces 321, 322.

[0024] The third main surface 321 of the solid electrolyte layer 32 includes a recess recessed toward the negative electrode current collector 20, and the positive electrode layer 31 is accommodated in this recess. The width of the third main surface 321 is greater than the width of the fourth main surface 322, and as a result, as shown in FIG. 2( a), the second side surface 323 is inclined so as to approach the center of the solid electrolyte layer 32 as it approaches the fourth main surface 322. In other words, the solid electrolyte layer 32 has a shape that gradually narrows as it approaches the negative electrode current collector 20.

[0025] 1(b) and 2(b), the power generating element 30 in this embodiment further includes an anode layer 33 in addition to the above-described cathode layer 31 and solid electrolyte layer 32 when the all-solid-state battery 1 is charged. This anode layer 33 is an alkali metal layer 33a mainly composed of alkali metal that is released from the cathode layer 31, reaches the main surface of the anode current collector 20 via the solid electrolyte layer 32, and precipitates thereon as the all-solid-state battery 1 is charged. The volume of this alkali metal layer 33a increases as the alkali metal precipitates as the all-solid-state battery 1 is charged, but decreases as the alkali metal disappears (moves toward the cathode layer 31) as the all-solid-state battery 1 is discharged.

[0026] The presence of such an alkali metal layer 33a can ensure the battery capacity of the all-solid-state battery 1. The alkali metal layer 33a may be mainly composed of lithium metal, and in this case, the battery capacity of the all-solid-state battery 1 can also be ensured.

[0027] The alkali metal layer 33a of this embodiment is interposed between the solid electrolyte layer 32 and the negative electrode current collector 20 when the all-solid-state battery 1 is in a charged state, while as shown in FIG. 1(a), this alkali metal layer 33a is not present in the power generating element 30 when the all-solid-state battery 1 is in a fully discharged state.

[0028] The outer periphery of the power generating element 30 is covered with an elastic body 40. This elastic body 40 is interposed between the positive electrode current collector 10 and the negative electrode current collector 20, and the upper and lower ends of the elastic body 40 are fixed to the negative electrode current collector 20 and the positive electrode current collector 10. The elastic body 40 is not particularly limited, but a material that has elasticity but does not have electronic conductivity or ionic conductivity can be used.

[0029] For example, a rubber material can be used for the elastic body 40, and examples of the rubber material that can be used include natural rubber and urethane rubber. The elastic body 40 is not particularly limited, but can be formed by laminating the positive electrode current collector 10, the power generating element 30, and the negative electrode current collector 20, and then attaching a rubber material to the outer periphery of the power generating element 30 via an adhesive layer, or by applying and drying a rubber material in paste form.

[0030] As shown in FIGS. 1(a) and 2(a), the elastic body 40 of this embodiment covers the entire second side surface 323 of the solid electrolyte layer 32 of the power generating element 30 when the all-solid-state battery 1 is fully discharged. As shown in FIGS. 1(b) and 2(b), the elastic body 40 covers the second side surface 323 of the solid electrolyte layer 32 and the outer periphery (side surface) of the alkali metal layer 33a when the all-solid-state battery 1 is charged. That is, the elastic body 40 expands in the stacking direction in response to the expansion of the power generating element 30 accompanying the deposition of the alkali metal layer 33a, thereby covering the entire outer periphery of the power generating element 30 during both charging and discharging. From the viewpoint of the ability to follow the expansion and contraction of the power generating element 30, the elastic modulus of the elastic body 40 is preferably less than 1 GPa.

[0031] The elastic body 40 has an inner circumferential surface 401 and an outer circumferential surface 402. The inner circumferential surface 401 is in contact with the power-generating element 30 and is fixed to the power-generating element 30. As shown in FIGS. 2(a) and 2(b), the inner circumferential surface 401 includes a first contact point P1 that contacts the power-generating element 30. Here, the first contact point P1 is the innermost contact point between the inner circumferential surface 401 of the elastic body 40 and the outer circumferential portion of the solid electrolyte layer 32 on the negative electrode layer 33 side, and in this embodiment, it is also the outermost peripheral edge of the fourth main surface 322 of the solid electrolyte layer 32.

[0032] The first contact point P1 is located closer to the center of the positive electrode current collector 10 than the second contact point P2. In other words, when the first contact point P1 is projected onto the main surface of the positive electrode current collector 10 in a direction perpendicular to the main surface in a cross-sectional view, the first contact point P1 is located at a point closer to the center of the positive electrode current collector 10 than the second contact point P2. The second contact point P2 is the outermost contact point between the positive electrode current collector 10 and the positive electrode layer 31. It is sufficient that the relative positional relationship between the first contact point P1 and the second contact point P2 is established in at least one cross section. It is also preferable that the above-described positional relationship is established around the entire circumference of the power generating element 30.

[0033] In this embodiment, the angle ψ between the first virtual line L1 and the second virtual line L2 is preferably 90° to 180° (90°<ψ<180°). Here, the first virtual line L1 is an imaginary line segment connecting the first contact point P1 and the outermost circumferential end point P3 in a cross-sectional view. The outermost circumferential end point P3 is the outermost point on the third main surface 321 of the solid electrolyte layer 32 facing the positive electrode current collector 10. The second virtual line L2 is an imaginary line segment substantially parallel to the main surface of the positive electrode current collector 10 that is not covered by the solid electrolyte layer 32 in a cross-sectional view.

[0034] When the angle ψ satisfies the above relationship, a space in which the elastic body 40 can be disposed can be formed between the second side surface 323 of the solid electrolyte layer 32 and the negative electrode current collector 20, making it possible to easily form the elastic body 40 of this embodiment. Furthermore, in this embodiment, the solid electrolyte layer 32 is in contact with the positive electrode current collector 10, so the angle ψ satisfies the above relationship and a space in which the elastic body 40 can be disposed can be formed.

[0035] In this embodiment, the elastic body 40 covers the entire power generating element 30, but is not limited to this. It is sufficient that the elastic body 40 covers at least the vicinity of the contact portion of the power generating element 30 with the negative electrode current collector 20. However, from the viewpoint of improving manufacturability, it is preferable that the elastic body 40 covers the entire power generating element 30.

[0036] Similarly, as in this embodiment, from the viewpoint of improving manufacturability, the maximum width (maximum outer diameter) W p is the maximum width W of the solid electrolyte layer 32 cs It is preferable that it is larger than (W p >W cs ) is the maximum width (maximum outer diameter) W of the elastic body 40 p is the maximum width W of the solid electrolyte layer 32 cs It may be less than (W p ≦W cs ).

[0037] In addition, in this embodiment, the case where the end of the solid electrolyte layer 32 has the continuously inclined second side surface 323 has been described as an example, but this is not limited to this. The solid electrolyte layer 32 may have an end shape as shown in Figures 3(a) to 3(c). Figures 3(a) to 3(c) are cross-sectional views showing examples of first to third modified examples of the solid electrolyte layer in the embodiment of the present invention.

[0038] 3(a) is a cross-sectional view showing a first modified example. In this first modified example, the second side surface 323 has a surface that is approximately perpendicular to the main surface of the positive electrode current collector 10. The end shape of the first modified example can be formed, for example, by punching and cutting the end of the solid electrolyte layer 32 in order to adjust the width of the power generating element 30.

[0039] 3(b) is a cross-sectional view showing a second modified example. In this second modified example, a protrusion is further formed that protrudes from the lower part of the second side surface 323. The end shape of the second modified example can be formed, for example, by placing a sheet-like solid electrolyte layer 32 on the positive electrode layer 31 and then pressing the solid electrolyte layer 32 toward the positive electrode layer 32.

[0040] 3(c) is a cross-sectional view showing a third modified example. In this third modified example, the outer periphery of the third main surface 321 of the solid electrolyte layer 32 is not in contact with the main surface of the positive electrode current collector 10. The end shape of the third modified example is formed, for example, when, after pressing the sheet-like solid electrolyte layer 32, the end of the solid electrolyte layer 32 is slightly peeled off from the positive electrode current collector 10. In this case, the outermost periphery end point P3 is the outermost end point of the outer periphery of the solid electrolyte layer 32 that is not in contact with but faces the main surface of the positive electrode current collector 10.

[0041] In the first to third modified examples as described above, the angle ψ between the first virtual line L1 and the second virtual line L2 can be set to 90° to 180°, and a space in which the elastic body 40 can be placed can be formed between the second side surface 323 of the solid electrolyte layer 32 and the negative electrode current collector 20, making it possible to easily form the elastic body 40.

[0042] If alkali metal ions migrating through the solid electrolyte layer are deposited in a region (non-opposing region) outside the opposing region of the negative electrode current collector facing the positive electrode layer, the alkali metal deposited in the non-opposing region is farther from the positive electrode layer than the alkali metal deposited in the opposing region, making it more difficult for the alkali metal to migrate to the positive electrode layer during discharge. In contrast, in the all-solid-state battery 1 of this embodiment, the first contact P1 is located more inward than the second contact P2, making it easier for alkali metal ions migrating through the solid electrolyte layer 32 to reach the opposing region. Furthermore, the elastic body 40, which satisfies this positional relationship between the first and second contacts P1 and P2, can restrict the migration of alkali metal ions to the non-opposing region through its inner circumferential surface 401. Furthermore, the elastic body 40 can follow the expansion and contraction of the power generating element 30 due to changes in the volume of the alkali metal layer 33a, thereby maintaining the effect of restricting the migration of alkali metal ions even when the power generating element 30 expands and contracts. Therefore, in the all-solid-state battery 1 of this embodiment, the alkali metal layer 33a is more likely to deposit in the opposing region, so that a decrease in capacity can be suppressed (cycle characteristics can be improved).

[0043] Generally, all-solid-state batteries are used with a load applied in the stacking direction. However, because the alkali metal layer is relatively soft, it may stretch on the negative electrode current collector due to the load and protrude from the opposing region, resulting in a decrease in capacity. In contrast, in the all-solid-state battery 1 of this embodiment, the alkali metal layer 33a is covered on the side by the elastic body 40, making it difficult for the layer to stretch due to the load, thereby suppressing a decrease in capacity.

[0044] Incidentally, if the first contact P1 is located outside the second contact P2, a gap is formed between the alkali metal layer deposited in the opposing region of the negative electrode current collector and the elastic body, resulting in the alkali metal being deposited in regions other than the opposing region.

[0045] Furthermore, when using a power generating element that does not have a negative electrode layer when the battery is fully discharged, it is difficult to provide a member that surrounds the periphery of the negative electrode layer because the negative electrode layer does not exist during the manufacturing of the all-solid-state battery. In contrast, in this embodiment, by providing an expandable elastic body 40 on the negative electrode layer side of the solid electrolyte layer 32, it is possible to cover the periphery of the alkali metal layer 33a in accordance with the deposition of the alkali metal layer 33a, and by arranging an elastic body that can limit the movement of alkali metal ions to areas other than the facing area, it is possible to suppress the deposition of alkali metal in areas other than the facing area.

[0046] Second Embodiment Next, a second embodiment will be described with reference to the drawings. Fig. 4(a) is a cross-sectional view showing an example of an all-solid-state battery in a fully discharged state in the second embodiment, and Fig. 4(b) is a cross-sectional view showing an example of an all-solid-state battery in a charged state in the second embodiment. Fig. 5 is an enlarged cross-sectional view of part V in Fig. 4(b).

[0047] This embodiment differs from the first embodiment in that the negative electrode layer 33B further includes an intermediate layer 33b, but other configurations are similar to those of the first embodiment. Below, only the intermediate layer 33b of the second embodiment will be described, and parts having the same configuration as those of the first embodiment will be assigned the same reference numerals and will not be described again.

[0048] 4(a), when the all-solid-state battery 1B is in a fully discharged state, the intermediate layer 33b is interposed between the fourth main surface 322 of the solid electrolyte layer 32 and the negative electrode current collector 20. The intermediate layer 33b is a layer for assisting deposition of the alkali metal layer 33a. The intermediate layer 33b contains a material capable of absorbing and releasing alkali metal ions, and may contain, for example, a material having electronic conductivity, a material having ionic conductivity, a material having both electronic conductivity and ionic conductivity, or a mixture of these.

[0049] As the material having electronic conductivity, for example, particles of a metal such as silver capable of absorbing lithium ions can be used. As the material having ionic conductivity, a general electrolyte can be used. As the material having both electronic conductivity and ionic conductivity, a carbon material such as graphite can be used.

[0050] The outer periphery (side surface) of this intermediate layer 33b is also covered with the elastic body 40. As shown in Fig. 4(b) , the alkali metal layer 33a of this embodiment is deposited between the intermediate layer 33b and the negative electrode current collector 20 when the all-solid-state battery 1B is in a charged state, but as the elastic body 40 stretches, the alkali metal layer 33a is covered with the elastic body 40, as in the first embodiment.

[0051] 5, in this embodiment as well, the first contact P1 is located more inward of the second contact P2 in the all-solid-state battery 1, and therefore, similarly to the first embodiment, deposition of the alkali metal layer 33a in regions other than the opposing region can be suppressed. Therefore, the all-solid-state battery 1 of this embodiment can suppress a decrease in capacity.

[0052] Although the embodiments of the present invention have been described above, these embodiments are described to facilitate understanding of the present invention and are not described to limit the present invention. Therefore, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention.

[0053] For example, the cross-sectional shape of the positive electrode layer 31 is not limited to a trapezoid. The cross-sectional shape of the positive electrode layer 31 may be any polygonal shape that narrows toward the negative electrode current collector 20. Alternatively, the cross-sectional shape may be a semicircular shape in which the second main surface 312 is curved so as to protrude toward the negative electrode current collector 20. In this case, the shape of the solid electrolyte layer 32 may also follow the shape of the second main surface 312 of the positive electrode layer 31.

[0054] Furthermore, although the outer peripheral surface 402 of the elastic body 40 in the above embodiment is substantially perpendicular to the positive electrode current collector 10 and the negative electrode current collector 20, the present invention is not limited to this.

[0055] In addition, in the second embodiment, an example has been given in which the alkali metal layer 33b is formed between the negative electrode current collector 20 and the intermediate layer 33b, but this is not limitative, and the alkali metal layer 33b may be formed between the solid electrolyte layer 32 and the intermediate layer 33b. [Explanation of symbols]

[0056] 1,1B…All-solid-state battery 10...Positive electrode current collector 20...Negative electrode current collector 30...Power generation element 31...Positive electrode layer 311, 312...First and second principal surfaces 313...First aspect 32...Solid electrolyte layer 321, 322...Third and fourth principal surfaces 323...Second Aspect 33,33B…Negative electrode layer 33a...alkali metal layer 33b…middle class 40...Elastic body 401…Inner peripheral surface 402...Outer surface P1, P2: First and second contacts P3…Outermost edge point

Claims

1. a power generating element in which an anode layer, a solid electrolyte layer, and a cathode layer are stacked in this order; an elastic body covering the outer periphery of the power generating element; a negative electrode current collector in contact with the negative electrode layer; a positive electrode current collector in contact with the positive electrode layer, the solid electrolyte layer covers a surface of the positive electrode layer formed on the positive electrode current collector, an all-solid-state battery, in which, in a cross-sectional view, a first contact point that is located innermost among contact points between the outer periphery of the solid electrolyte layer on the negative electrode layer side and the elastic body is located more inner than a second contact point that is located outermost among contact points between the positive electrode current collector and the positive electrode layer.

2. The all-solid-state battery according to claim 1, The elastic body has an elastic modulus of less than 1 GPa.

3. The all-solid-state battery according to claim 1 or 2, The solid electrolyte layer and the positive electrode current collector are in contact with each other.

4. The all-solid-state battery according to any one of claims 1 to 3, the angle ψ between the first imaginary line and the second imaginary line satisfies 90°<ψ<180°; the first virtual line is a virtual line segment that connects the first contact point and an outermost point on a surface of the solid electrolyte layer that faces the positive electrode current collector in the cross-sectional view, the second imaginary line is an imaginary line segment that is approximately parallel to a main surface of the positive electrode current collector that is not covered with the solid electrolyte layer in the cross-sectional view.

5. The all-solid-state battery according to any one of claims 1 to 4, The negative electrode layer in a fully charged state of the all-solid-state battery includes an alkali metal layer containing an alkali metal as a main component.

6. The all-solid-state battery according to claim 5, The alkali metal layer is an all-solid-state battery containing lithium metal as a main component.

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