All-solid-state battery

Abstract

Provided, in an all-solid-state battery provided with a solid electrolyte layer, is a means which can suppress short-circuiting to a greater degree while suppressing a decrease in energy density. Provided is an all-solid-state battery provided with an electric power generation element including a positive electrode which has a positive electrode active material layer, a negative electrode which has a negative electrode active material layer, and a solid electrolyte layer which is interposed between the positive electrode and the negative electrode and contains a solid electrolyte. The solid electrolyte layer includes a first solid electrolyte layer which is adjacent to the positive electrode active material layer and includes a first solid electrolyte and a first binder and a second solid electrolyte layer which is adjacent to the negative electrode active material layer and includes a second solid electrolyte and a second binder. Each of the first binder and the second binder includes a specific binder. At least a part of an outer peripheral end of the positive electrode active material layer is positioned inside an outer peripheral end of the first solid electrolyte layer or an outer peripheral end of the second solid electrolyte layer in a plan view of the electric power generation element.

Description

All solid state battery

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

[0002] In recent years, there has been active research and development into all-solid-state batteries, such as all-solid-state lithium secondary batteries that use oxide- or sulfide-based solid electrolytes. Solid electrolytes are materials primarily composed of ionic conductors that can conduct lithium ions in a solid state. Therefore, all-solid-state batteries have the advantage that, in principle, they do not encounter the various problems associated with flammable organic electrolytes, as occurs in conventional liquid-based lithium secondary batteries.

[0003] In an all-solid-state battery, a solid electrolyte layer containing a solid electrolyte is disposed between a positive electrode and a negative electrode. From the viewpoint of improving energy density, it is desirable to reduce the thickness of the solid electrolyte layer. However, it is known that reducing the thickness makes it more likely for pinholes to form in the solid electrolyte, which makes it more likely for a short circuit to occur.

[0004] International Publication No. 2014 / 010043 discloses that the electrolyte layer (solid electrolyte layer) of an all-solid-state battery is configured by stacking a first solid electrolyte layer containing a sulfide solid electrolyte and a second solid electrolyte layer different from the first solid electrolyte layer containing the sulfide solid electrolyte. According to this document, by adopting this configuration, even if pinholes are formed in the first solid electrolyte layer and the second solid electrolyte layer, the possibility of these pinholes connecting so as to penetrate through the thickness direction of the electrolyte layer (solid electrolyte layer) is extremely low, thereby suppressing short circuits.

[0005] However, according to the investigations of the present inventors, it has become clear that even if the techniques described in the above documents are employed, there are cases in which short circuits cannot be sufficiently suppressed.

[0006] Therefore, an object of the present invention is to provide a means for further suppressing short circuits while suppressing a decrease in energy density in an all-solid-state battery having a solid electrolyte layer.

[0007] The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result, have found that the above-mentioned problems can be solved by configuring a solid electrolyte layer in which a first solid electrolyte layer and a second solid electrolyte layer are stacked, and controlling the type of binder contained in each layer and the size of each layer, thereby completing the present invention.

[0008] That is, one aspect of the present invention is an all-solid-state battery including a power generating element having a positive electrode having a positive electrode active material layer, a negative electrode having a negative electrode active material layer, and a solid electrolyte layer interposed between the positive electrode and the negative electrode and containing a solid electrolyte, wherein the solid electrolyte layer has a first solid electrolyte layer adjacent to the positive electrode active material layer and containing a first solid electrolyte and a first binder, and a second solid electrolyte layer adjacent to the negative electrode active material layer and containing a second solid electrolyte and a second binder, the first binder containing at least one selected from the group consisting of polytetrafluoroethylene, carboxymethyl cellulose, polyethylene oxide, polyvinyl alcohol, and polyethylene, and the second binder containing at least one selected from the group consisting of styrene-butadiene rubber, polyvinylidene fluoride, polybutylene terephthalate, and the like. phthalate, polyethylene terephthalate, carboxymethyl cellulose, polyethylene oxide, polyvinyl alcohol, polyethylene, polypropylene, polymethylpentene, polybutene, polyether nitrile, polyacrylonitrile, polyimide, polyamide, polyamideimide, ethylene-vinyl acetate copolymer, polyvinyl chloride, ethylene-propylene-diene copolymer, styrene-butadiene-styrene block copolymer, and styrene-isoprene-styrene block copolymer, and when the power generating element is viewed from above, at least a part of the outer circumferential edge of the positive electrode active material layer is located more inward than the outer circumferential edge of the first solid electrolyte layer or the outer circumferential edge of the second solid electrolyte layer.

[0009] Fig. 1 is a cross-sectional view schematically showing the overall structure of a stacked-type (internal parallel connection type) all-solid-state lithium secondary battery (stacked-type secondary battery) according to one embodiment of the present invention. Fig. 2 is an enlarged cross-sectional view of a cell layer 19 of the stacked-type secondary battery according to one embodiment of the present invention.

[0010] One aspect of the present invention is an all-solid-state battery including a power generating element having a positive electrode having a positive electrode active material layer, a negative electrode having a negative electrode active material layer, and a solid electrolyte layer interposed between the positive electrode and the negative electrode and containing a solid electrolyte, wherein the solid electrolyte layer has a first solid electrolyte layer adjacent to the positive electrode active material layer and containing a first solid electrolyte and a first binder, and a second solid electrolyte layer adjacent to the negative electrode active material layer and containing a second solid electrolyte and a second binder, the first binder containing at least one selected from the group consisting of polytetrafluoroethylene, carboxymethyl cellulose, polyethylene oxide, polyvinyl alcohol, and polyethylene, and the second binder containing at least one selected from the group consisting of styrene-butadiene rubber, polyvinylidene fluoride, polybutylene terephthalate, The present invention relates to an all-solid-state battery including a solid electrolyte layer, the all-solid-state battery including a solid electrolyte layer, the all-solid-state battery including a solid electrolyte layer, and the cathode active material layer, the cathode active material layer, and the cathode active material layer are all-solid-state batteries, and the cathode active material layer is at least one selected from the group consisting of ethylene-vinyl acetate copolymer, polyvinyl chloride, ethylene-propylene-diene copolymer, styrene-butadiene-styrene block copolymer, and styrene-isoprene-styrene block copolymer, and the cathode active material layer is at least one selected from the group consisting of ethylene-vinyl acetate copolymer, polyethylene terephthalate, carboxymethyl cellulose, polyethylene oxide, polyvinyl alcohol, polyethylene, polypropylene, polymethylpentene, polybutene, polyether nitrile, polyacrylonitrile, polyimide, polyamide, polyamideimide, ethylene-vinyl acetate copolymer, polyvinyl chloride, ethylene-propylene-diene copolymer, styrene-butadiene-styrene block copolymer, and styrene-isoprene-styrene block copolymer, and the cathode active material layer is at least partly located inside the outer circumferential edge of the first solid electrolyte layer or the outer circumferential edge of the second solid electrolyte layer when the power generating element is viewed from above.

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicate explanations will be omitted. Furthermore, the dimensional proportions in the drawings are exaggerated for the convenience of explanation and may differ from the actual proportions.

[0012] FIG. 1 is a cross-sectional view schematically illustrating the overall structure of a stacked-type (internal parallel connection type) all-solid-state lithium secondary battery (hereinafter simply referred to as a "stacked-type secondary battery") according to one embodiment of the present invention. The stacked-type secondary battery 10a shown in FIG. 1 has a structure in which a substantially rectangular power generating element 21, where charge and discharge reactions actually occur, is sealed inside a laminate film 29, which is a battery exterior. Note that FIG. 1 shows a cross-section of the stacked-type secondary battery during charging, and thus, a negative electrode active material layer 13 made of lithium metal is present between the negative electrode current collector 11' and the solid electrolyte layer 17. Furthermore, a pressure member (not shown) applies a restraining pressure to the stacked-type secondary battery 10a in the stacking direction of the power generating element 21. Therefore, the volume of the power generating element 21 is maintained constant.

[0013] As shown in FIG. 1 , a power generating element 21 of a stacked secondary battery 10 a of this embodiment has a configuration in which a negative electrode in which a negative electrode active material layer 13 containing lithium metal is disposed on both sides of a negative electrode current collector 11 ′, a solid electrolyte layer 17, and a positive electrode in which a positive electrode active material layer 15 containing a lithium transition metal composite oxide is disposed on both sides of a positive electrode current collector 11 ″ are laminated. Specifically, the negative electrode, solid electrolyte layer, and positive electrode are laminated in this order such that one negative electrode active material layer 13 and an adjacent positive electrode active material layer 15 face each other with the solid electrolyte layer 17 interposed therebetween. As a result, adjacent negative electrode, solid electrolyte layer, and positive electrode constitute one unit cell layer 19. Therefore, the stacked secondary battery 10 a shown in FIG. 1 can also be said to have a configuration in which a plurality of unit cell layers 19 are stacked and electrically connected in parallel.

[0014] A negative electrode current collector 25 and a positive electrode current collector 27 that are electrically connected to the respective electrodes (negative and positive electrodes) are attached to the negative electrode current collector 11′ and the positive electrode current collector 11″, respectively, and are configured to be sandwiched between the ends of the laminate film 29 and led out of the laminate film 29. The negative electrode current collector 25 and the positive electrode current collector 27 may be attached to the negative electrode current collector 11′ and the positive electrode current collector 11″ of the respective electrodes by ultrasonic welding, resistance welding, or the like, via a negative electrode terminal lead and a positive electrode terminal lead (not shown), respectively, as necessary.

[0015] In the above description, an embodiment of the lithium secondary battery according to the present invention has been described using a stacked (internal parallel connection) all-solid-state lithium secondary battery as an example. However, the type of lithium secondary battery to which the present invention is applicable is not particularly limited, and the present invention can also be applied to a bipolar lithium secondary battery.

[0016] 2 is an enlarged cross-sectional view of a cell layer 19 of a stacked secondary battery according to one embodiment of the present invention. As shown in FIG. 2, the cell layer 19 constituting the stacked secondary battery 10a according to this embodiment has a positive electrode constituted by a positive electrode current collector 11" and a positive electrode active material layer 15 disposed on the surface thereof, and a negative electrode constituted by a negative electrode current collector 11' and a negative electrode active material layer 13 disposed on the surface thereof. A solid electrolyte layer 17 having a two-layer laminated structure of a first solid electrolyte layer 17a and a second solid electrolyte layer 17b is disposed between the positive electrode and the negative electrode, and the first solid electrolyte layer 17a is adjacent to the positive electrode active material layer 15, and the second solid electrolyte layer 17b is adjacent to the negative electrode active material layer 13, respectively. Here, in the embodiment shown in FIG. 2, when the cell layer 19 is viewed from above, the positive electrode active material layer The outer peripheral edge of the negative electrode active material layer 13 is located inside the outer peripheral edge of the first solid electrolyte layer 17a over its entire circumference (in other words, the first solid electrolyte layer 17a is slightly larger than the positive electrode active material layer 15). This configuration prevents dendrite growth from the outer peripheral edge of the negative electrode active material layer 13 and the resulting short circuit caused by contact between the dendrite and the positive electrode active material layer 15. The outer peripheral edge of the second solid electrolyte layer 17b of this embodiment is located inside the outer peripheral edge of the first solid electrolyte layer 17a over its entire circumference. The outer peripheral edge of the negative electrode active material layer 13 of this embodiment coincides with the outer peripheral edge of the second solid electrolyte layer 17b over its entire circumference.

[0017] In the embodiment shown in FIG. 2, the first solid electrolyte layer 17a is made of Li as the first solid electrolyte. ６ P.S. ５ The first solid electrolyte layer 17a contains Li, Cl, and polytetrafluoroethylene (PTFE) as a first binder. ６ P.S. ５The Cl is entangled and held in the fibrillated polytetrafluoroethylene (PTFE), and the first solid electrolyte layer 17a has a high mechanical strength sufficient to exist as a free-standing film. As a result, when the first solid electrolyte layer 17a is made one size larger than the positive electrode active material layer 15, cracks and chips at the outer peripheral edge of the first solid electrolyte layer 17a are suppressed, and the effects of the present invention can be more significantly exhibited. Furthermore, in the embodiment shown in FIG. 2, the second solid electrolyte layer 17b adjacent to the negative electrode active material layer 13 contains Li as the second solid electrolyte. ６ P.S. ５ The battery contains styrene-butadiene rubber (SBR) as a second binder. By using a material that is resistant to decomposition even at the reduction potential of the negative electrode as the second binder, deterioration of the solid electrolyte layer due to repeated charge and discharge can be suppressed, and the capacity retention rate can be improved.

[0018] The main components of the stacked secondary battery 10a will be described below.

[0019] [Current Collectors] The current collectors (negative electrode current collector 11′ and positive electrode current collector 11″) have the function of mediating the transfer of electrons from the electrode active material layer. There are no particular restrictions on the material that constitutes the current collectors. Examples of materials that can be used to constitute the current collectors include metals such as aluminum, nickel, iron, stainless steel, titanium, and copper, as well as conductive resins. There are also no particular restrictions on the thickness of the current collectors, but one example is 10 to 100 μm.

[0020] [Negative Electrode Active Material Layer] The negative electrode active material layer 13 contains a negative electrode active material and may optionally contain a solid electrolyte, a binder, and a conductive additive. The type of negative electrode active material is not particularly limited, but examples include carbon materials, metal oxides, and metal active materials. Furthermore, a lithium-containing active material may be used as the negative electrode active material. Such a negative electrode active material is not particularly limited as long as it is a lithium-containing active material, and examples thereof include metallic lithium and lithium-containing alloys. Examples of lithium-containing alloys include alloys of Li with at least one of In, Al, Si, Sn, Mg, Au, Ag, and Zn. The negative electrode active material preferably contains metallic lithium or a lithium-containing alloy, a silicon-based negative electrode active material, or a tin-based negative electrode active material, and particularly preferably contains metallic lithium or a lithium-containing alloy. When metallic lithium or a lithium-containing alloy is used as the negative electrode active material, the lithium secondary battery is preferably a so-called lithium deposition type in which lithium metal as the negative electrode active material is deposited on the negative electrode current collector during charging, as shown in FIGS. 1 and 2 . In this case, the layer of lithium metal deposited on the negative electrode current collector during the charging process becomes the negative electrode active material layer, and the thickness of the negative electrode active material layer increases as the charging process progresses and decreases as the discharging process progresses. The negative electrode active material layer does not need to be present during full discharge, but in some cases, a negative electrode active material layer consisting of a certain amount of lithium metal may be present during full discharge. The thickness of the negative electrode active material layer (lithium metal layer) during full charge is not particularly limited, but is typically 0.1 to 1000 μm.

[0021] [Solid Electrolyte Layer] The solid electrolyte layer 17 has a configuration in which a first solid electrolyte layer 17a containing a first solid electrolyte and a first binder and a second solid electrolyte layer 17b containing a second solid electrolyte and a second binder are stacked. In the stack-type secondary battery 10a according to this embodiment shown in Figure 2, the solid electrolyte layer 17 is arranged so that the first solid electrolyte layer 17a is adjacent to the positive electrode active material layer 15 and the second solid electrolyte layer 17b is adjacent to the negative electrode active material layer 13.

[0022] (First Solid Electrolyte and Second Solid Electrolyte) The first solid electrolyte constituting the first solid electrolyte layer and the second solid electrolyte constituting the second solid electrolyte layer are not particularly limited, and any conventionally known solid electrolyte may be used as appropriate. Examples of the solid electrolyte include sulfide-based solid electrolytes and oxide-based solid electrolytes.

[0023] Examples of sulfide solid electrolytes include LiI-Li ２ S-SiS ２ , LiI-Li ２ S-P ２ O ５ , LiI-Li ３ P.O. ４ -P ２ S ５ , Li ２ S-P ２ S ５ , LiI-Li ３ P.S. ４ , LiI-LiBr-Li ３ P.S. ４ , Li ３ P.S. ４ , Li ２ S-P ２ S ５ - LiI, Li ２ S-P ２ S ５ -Li ２ O, Li ２ S-P ２ S ５ -Li ２ O-LiI, Li ２ S-SiS ２ , Li ２ S-SiS ２ - LiI, Li ２ S-SiS ２ - LiBr, Li ２ S-SiS ２ -LiCl, Li ２ S-SiS ２ -B ２ S ３ - LiI, Li ２ S-SiS ２ -P ２ S ５ - LiI, Li ２ S-B ２ S ３ , Li２ S-P ２ S ５ -Z ｍ S ｎ (where m and n are positive numbers, and Z is Ge, Zn, or Ga), Li ２ S-GeS ２ , Li ２ S-SiS ２ -Li ３ P.O. ４ , Li ２ S-SiS ２ -Li ｘ MO ｙ (where x and y are positive numbers, and M is any of P, Si, Ge, B, Al, Ga, and In). ２ S-P ２ S ５ " is written by Li ２ S and P ２ S ５ The same applies to other descriptions.

[0024] The sulfide solid electrolyte is, for example, Li ３ P.S. ４ It may have a Li framework. ４ P ２ S ７ It may have a Li framework. ４ P ２ S ６ It may have a Li skeleton. ３ P.S. ４ Examples of sulfide solid electrolytes having a skeleton include LiI-Li ３ P.S. ４ , LiI-LiBr-Li ３ P.S. ４ , Li ３ P.S. ４ In addition, Li ４ P ２ S ７ Examples of the sulfide solid electrolyte having a skeleton include a Li-P-S solid electrolyte called LPS (for example, Li ７ P ３ S １１ ) can be mentioned. In addition, examples of sulfide solid electrolytes include Li（４－ｘ） Ge （１－ｘ） P ｘ S ４ (x satisfies 0<x<1), or the like may be used. Among them, a sulfide solid electrolyte containing a P element is preferable. Furthermore, the sulfide solid electrolyte may contain a halogen (F, Cl, Br, I), and an example thereof is Li. ６ P.S. ５ X (wherein X is Cl, Br or I, preferably Cl).

[0025] Examples of oxide solid electrolytes include compounds having a NASICON structure. An example of a compound having a NASICON structure is a compound represented by the general formula Li １＋ｘ Al ｘ Ge ２－ｘ (P.O. ４ ) ３ (0≦x≦2) (LAGP), a compound represented by the general formula Li １＋ｘ Al ｘ Ti ２－ｘ (P.O. ４ ) ３ (0≦x≦2) (LATP) and the like. Another example of the oxide solid electrolyte is LiLaTiO (for example, Li ０．３４ La ０．５１ TiO ３ ), LiPON (e.g., Li ２．９ P.O. ３．３ N ０．４６ ), LiLaZrO (e.g., Li ７ La ３ Zr ２ O １２ ) etc.

[0026] From the viewpoint of further improving the lithium ion conductivity of the solid electrolyte layer, it is preferable that both the first solid electrolyte and the second solid electrolyte are sulfide-based solid electrolytes, and both the first solid electrolyte and the second solid electrolyte are Li ６ P.S. ５ It is more preferable that the first solid electrolyte and the second solid electrolyte are X (wherein X is Cl, Br or I, and preferably Cl). However, the first solid electrolyte and the second solid electrolyte may be different types from each other.

[0027] The solid electrolyte is preferably in the form of particles. When the solid electrolyte is in the form of particles, its average particle diameter (D50) is not particularly limited, but is preferably 0.01 μm or more and 40 μm or less, more preferably 0.01 μm or more and 20 μm or less, even more preferably 0.1 μm or more and 10 μm or less, and even more preferably 0.1 μm or more and 1 μm or less. In this specification, the average particle diameter (D50) of the solid electrolyte is a value calculated as the average particle diameter of the solid electrolyte observed in several to several tens of fields of view using an observation means such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM).

[0028] (First Binder) The binder (first binder) contained in the first solid electrolyte layer includes at least one selected from the group consisting of polytetrafluoroethylene (PTFE), carboxymethyl cellulose (CMC), polyethylene oxide (PEO), polyvinyl alcohol (PVA), and polyethylene (PE). These binders can be fibrillated by applying shear force, entangling and holding the solid electrolyte. By using such a binder, the first solid electrolyte layer has high mechanical strength sufficient to exist as a free-standing film. This can suppress cracking and chipping at the outer peripheral edge of the first solid electrolyte layer, even if the first solid electrolyte layer is slightly larger than the positive electrode active material layer. From the viewpoint of further improving the mechanical strength of the first solid electrolyte layer, the first binder preferably includes PTFE, and more preferably consists solely of PTFE. Note that polytetrafluoroethylene may include polytetrafluoroethylene in which the terminals or part of the side chains are substituted (modified) with other substituents. In cases where the terminals or part of the side chains are substituted (modified) with other substituents, the proportion of structural units whose terminals or side chains have been substituted (modified) with other substituents in 100 mol % of all structural units is preferably 10 mol % or less, and more preferably 5 mol % or less.

[0029] The first binder may contain other binders than those described above. However, from the viewpoint of further improving the mechanical strength of the first solid electrolyte layer, the proportion of the other binders relative to the total mass of the first binder is preferably 10 mass % or less, more preferably 5 mass % or less, even more preferably 3 mass % or less, particularly preferably 1 mass % or less, and most preferably 0 mass % (i.e., no other binders are included).

[0030] When the first binder contains PTFE, the amount of PTFE in the first solid electrolyte layer is preferably 3% by mass or more and 50% by mass or less, more preferably 5% by mass or more and 30% by mass or less, and even more preferably 10% by mass or more and 20% by mass or less, relative to the total solid content of the first solid electrolyte layer. If the proportion is 3% by mass or more, the tensile strength of the first solid electrolyte layer is improved, resulting in a first solid electrolyte layer with excellent handleability. If the proportion is 50% by mass or less, the ionic conductivity of the first solid electrolyte layer is improved, resulting in a stacked secondary battery with excellent rate characteristics.

[0031] (Second Binder) The binder (second binder) contained in the second solid electrolyte layer is selected from the group consisting of styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVdF), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), carboxymethyl cellulose (CMC), polyethylene oxide (PEO), polyvinyl alcohol (PVA), polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), polybutene (PB), polyethernitrile (PEN), polyacrylonitrile (PAN), polyimide (PI), polyamide (PA), polyamideimide (PAI), ethylene-vinyl acetate copolymer (EVA), polyvinyl chloride (PVC), ethylene-propylene-diene copolymer, styrene-butadiene-styrene block copolymer, and styrene-isoprene-styrene block copolymer. These binders are not easily reductively decomposed by the negative electrode potential, and therefore can suppress deterioration of the second solid electrolyte layer due to repeated charge and discharge. From the viewpoint of further suppressing deterioration of the second solid electrolyte layer, the second binder preferably contains SBR or PVdF, more preferably consists of at least one of SBR and PVdF, and further preferably consists of SBR alone.

[0032] The second binder may contain other binders than those described above. However, from the viewpoint of further suppressing reductive decomposition of the second solid electrolyte layer due to the negative electrode potential, the proportion of the other binders relative to the total mass of the second binder is preferably 10 mass % or less, more preferably 5 mass % or less, even more preferably 3 mass % or less, particularly preferably 1 mass % or less, and most preferably 0 mass % (i.e., no other binders are included).

[0033] The amount of the second binder in the second solid electrolyte layer is preferably 1% by mass or more and 30% by mass or less, more preferably 3% by mass or more and 20% by mass or less, and even more preferably 5% by mass or more and 10% by mass or less, relative to the total solid content of the second solid electrolyte layer. If the proportion is 1% by mass or more, the mechanical strength of the second solid electrolyte layer is further improved, thereby more effectively suppressing short circuits. If the proportion is 30% by mass or less, the ionic conductivity of the second solid electrolyte layer is improved, thereby enabling a stacked secondary battery with excellent rate characteristics.

[0034] In the stacked secondary battery according to this embodiment, when the power generating element is viewed from above, it is essential that at least a portion (preferably the entire circumference) of the outer circumferential edge of the positive electrode active material layer is located inside the outer circumferential edge of the first solid electrolyte layer or the outer circumferential edge of the second solid electrolyte layer (in other words, at least one of the first solid electrolyte layer and the second solid electrolyte layer is slightly larger in size than the positive electrode active material layer). This configuration can prevent dendrite growth from the outer circumferential edge of the negative electrode active material layer and the resulting short circuit caused by contact between the dendrite and the positive electrode active material layer.

[0035] From the viewpoint of further preventing the above-described short circuit, it is preferable that, when the power generating element is viewed from above, at least a part (preferably the entire circumference) of the outer circumferential edge of the second solid electrolyte layer is located inside the outer circumferential edge of the first solid electrolyte layer (in other words, the first solid electrolyte layer is one size larger than the second solid electrolyte layer).

[0036] The thickness of the first solid electrolyte layer is not particularly limited, but is preferably in the range of 1 to 100 μm, and more preferably 10 to 50 μm. If the thickness is 1 μm or more, the mechanical strength of the first solid electrolyte layer can be further improved. If the thickness is 100 μm or less, the energy density of the battery can be further improved.

[0037] The thickness of the second solid electrolyte layer is also not particularly limited, but is preferably within a range of 0.1 to 100 μm, more preferably 0.5 to 50 μm, and even more preferably 1 to 10 μm. If the thickness is 0.1 μm or more, contact between the first solid electrolyte layer and the negative electrode active material layer is further suppressed, so deterioration of the first solid electrolyte layer can be more effectively suppressed. If the thickness is 100 μm or less, the energy density of the battery can be further improved.

[0038] From the viewpoint of further improving the ionic conductivity of the second solid electrolyte layer, the thickness of the second solid electrolyte layer is preferably equal to or greater than the maximum particle diameter of the second solid electrolyte. In this specification, the maximum particle diameter of the second solid electrolyte is measured by the following method. First, the second solid electrolyte to be measured is placed in a glass bottle and diluted with 1,3,5-trimethylbenzene (mesitylene) so that the concentration of the second solid electrolyte is 0.5% by mass. One drop of the resulting diluted solution is placed in the center of a glass slide. A cover glass is placed over the diluted solution, and the cover glass is pressed down with a finger to wipe off any excess diluted solution. A specimen (preparation) is prepared by sealing the four edges of the cover glass with nail polish applied with a brush. The specimen is then placed in a particle image analyzer (Morphologi 4, manufactured by Malvern Panalytical) to measure the maximum particle diameter of the second solid electrolyte.

[0039] [Positive Electrode Active Material Layer] The positive electrode active material layer 15 essentially contains a positive electrode active material, and may contain a solid electrolyte, a binder, and a conductive additive as needed.

[0040] The type of the positive electrode active material contained in the positive electrode active material layer is not particularly limited, but may be LiCoO ２ , LiMnO ２ , LiNiO ２ , LiVO ２ , Li(Ni-Mn-Co)O ２ Layered rock salt active materials such as LiMn ２ O ４ , LiNi ０．５ Mn １．５ O ４ Spinel-type active materials such as LiFePO ４ , LiMnPO ４Olivine type active materials such as Li ２ FeSiO ４ , Li ２ MnSiO ４ Examples of oxide active materials other than those mentioned above include Si-containing active materials such as Li ４ Ti ５ O １２ Among them, Li(Ni-Mn-Co)O ２ Also, those in which part of these transition metals has been replaced with other elements (hereinafter simply referred to as "NMC composite oxides") are preferably used as the positive electrode active material.

[0041] In addition, a sulfur-based positive electrode active material is also one of the preferred embodiments. Examples of the sulfur-based positive electrode active material include particles or thin films of organic sulfur compounds or inorganic sulfur compounds, and any material can be used as long as it is capable of releasing lithium ions during charging and absorbing lithium ions during discharging by utilizing the oxidation-reduction reaction of sulfur.

[0042] The content of the positive electrode active material in the positive electrode active material layer is preferably 50 to 100% by mass, more preferably 55 to 95% by mass, and even more preferably 60 to 90% by mass.

[0043] The thickness of the positive electrode active material layer varies depending on the intended configuration of the all-solid-state battery, but is usually 0.1 to 1000 μm, and preferably 10 to 100 μm.

[0044] Although one embodiment of the secondary battery of the present invention has been described above, the present invention is not limited to the configuration described in the above embodiment and can be modified as appropriate based on the claims. The following embodiments are also included within the scope of the present invention: an all-solid-state battery according to claim 1 having the features of claim 2; an all-solid-state battery according to claim 1 or 2 having the features of claim 3; an all-solid-state battery according to claim 3 having the features of claim 4; and an all-solid-state battery according to any one of claims 1 to 4 having the features of claim 5.

[0045] The present invention will be described in more detail below with reference to examples. However, the technical scope of the present invention is not limited to the following examples. In the following, the instruments and devices used in the glove box were thoroughly dried beforehand.

[0046] <Examples of Preparation of Evaluation Cell> [Example 1] (Preparation of Tabbed Positive Electrode) In a glove box with an argon atmosphere having a dew point of −68° C. or less, an NMC composite oxide (LiNi) ０．８ Mn ０．１ Co ０．１ O ２ ) 70 parts by mass, acetylene black 10 parts by mass as a conductive additive, and an argyrodite-type sulfide solid electrolyte (Li ６ P.S. ５ 20 parts by mass of fluorine-containing silica (C1, average particle diameter (D50) 1 μm) was mixed using an agate mortar. 2 parts by mass of polytetrafluoroethylene (PTFE) as a binder was added to 100 parts by mass of the obtained mixed powder, and after lightly kneading, the mixture was kneaded for 2 minutes while applying shear force in the mortar. After confirming that the binder had been fibrillated, the obtained kneaded product was formed into a sheet having a thickness of 200 μm using a hand roller. The obtained sheet-like molded product was passed through a benchtop roll press to obtain a sheet-like positive electrode active material layer having a thickness of 100 μm. The sheet-like positive electrode active material layer was placed on etched aluminum foil as a positive electrode current collector, and the layers were bonded together using a benchtop roll press. The obtained laminate was cut so that the positive electrode active material layer was a square measuring 2.0 cm × 2.0 cm and the positive electrode current collector was a rectangle measuring 2.0 cm × 3.0 cm (at this time, so that the uncoated portion of the positive electrode active material layer was a rectangle measuring 2.0 cm × 1.0 cm). Then, a tab lead (made of aluminum) was welded to the uncoated portion of the positive electrode active material layer of the positive electrode current collector to obtain a tab-equipped positive electrode.

[0047] (Preparation of First Solid Electrolyte Layer) In a glove box with an argon atmosphere having a dew point of −68° C. or less, an argyrodite-type sulfide solid electrolyte (Li ６ P.S. ５80 parts by mass of HCl (average particle size (D50) 3 μm) and 20 parts by mass of polytetrafluoroethylene (PTFE) as a binder were mixed using an agate mortar, and then kneaded for 2 minutes while applying shear force in the mortar. After confirming that the binder was fibrillated, the resulting kneaded mixture was sandwiched between two SUS304 foils (thickness 50 μm) and heated on a hot plate at 80 ° C. using a hand roller to form a 200 μm thick sheet. The sheet-shaped product sandwiched between the SUS foils was stretched to a thickness of 50 μm by reducing the gap by 20 μm at a roll surface temperature of 80 ° C. using a tabletop roll press equipped with a heating mechanism, and then cut into a square measuring 2.5 cm × 2.5 cm to obtain a first solid electrolyte layer.

[0048] (Preparation of a laminate of a second solid electrolyte layer and a negative electrode current collector with a tab) In a glove box with an argon atmosphere having a dew point of −68° C. or less, an argyrodite-type sulfide solid electrolyte (Li ６ P.S. ５ 95 parts by mass of styrene-butadiene rubber (SBR, average particle diameter 1 μm) and 5 parts by mass of styrene-butadiene rubber (SBR) as a binder were dispersed in 1,3,5-trimethylbenzene as a solvent to a solids content of 47% by mass. The binder was previously adjusted to a concentration of 6% by mass using 1,3,5-trimethylbenzene. The resulting dispersion was stirred at 1000 rpm for 3 minutes using a planetary mixer to prepare a slurry. The resulting slurry was applied to a negative electrode current collector (made of SUS430, thickness 10 μm) to a film thickness of 10 μm after drying, and the solvent was dried on a hot plate at 80°C for 30 minutes. The obtained laminate was cut so that the second solid electrolyte layer was a square measuring 2.2 cm × 2.2 cm and the negative electrode current collector was a rectangle measuring 2.2 cm × 3.2 cm (at this time, so that the uncoated portion of the second solid electrolyte layer was a rectangle measuring 2.2 cm × 1.0 cm). Then, a tab lead (nickel-plated copper) was welded to the uncoated portion of the second solid electrolyte layer of the negative electrode current collector to obtain a laminate of the second solid electrolyte layer and the negative electrode current collector with a tab.

[0049] (Evaluation Cell) The "tabbed positive electrode," "first solid electrolyte layer," and "laminated body of second solid electrolyte layer and tabbed negative electrode current collector" prepared above were stacked so that the positive electrode active material layer was adjacent to one side of the first solid electrolyte layer, and so that the other side of the first solid electrolyte layer was adjacent to the second solid electrolyte layer, to form a power generation element. The power generation element was covered with a laminate film, and the tab portion was welded with a sealer. The laminate film was sealed using a vacuum sealer, leaving one side uncovered. The resulting cell was covered with a laminate film and sandwiched between two aluminum plates (thickness 5 mm) and subjected to hydrostatic pressing (CIP) at 80°C and 500 MPa for 1 minute. This bonded the interfaces of the positive electrode current collector, positive electrode active material layer, first solid electrolyte layer (thickness 35 μm after CIP), second solid electrolyte layer (thickness 5 μm after CIP), and negative electrode current collector, yielding an evaluation cell for this example.

[0050] [Example 2] The cutting in the above (preparation of a tabbed positive electrode) was performed so that the positive electrode active material layer was a square measuring 2.2 cm × 2.2 cm, and the positive electrode current collector was a rectangle measuring 2.2 cm × 3.2 cm (with the uncoated portion of the positive electrode active material layer being a rectangle measuring 2.2 cm × 1.0 cm). The cutting in the above (preparation of a first solid electrolyte layer) was performed so that the first solid electrolyte layer was a square measuring 2.2 cm × 2.2 cm. The cutting in the above (preparation of a laminate of a second solid electrolyte layer and a tabbed negative electrode current collector) was performed so that the second solid electrolyte layer was a square measuring 2.4 cm × 2.4 cm, and the negative electrode current collector was a rectangle measuring 2.4 cm × 3.4 cm (with the uncoated portion of the second solid electrolyte layer being a rectangle measuring 2.4 cm × 1.0 cm). Except for these points, the evaluation cell of this example was obtained in the same manner as in Example 1.

[0051] Example 3 An evaluation cell for this example was obtained in the same manner as in Example 1, except that in the above (production of a laminate of a second solid electrolyte layer and a tab-attached negative electrode current collector), polyvinylidene fluoride (PVdF) was used as the binder and butyl acetate was used as the solvent.

[0052] Comparative Example 1 The cutting in the above (preparation of a tabbed positive electrode) was performed so that the positive electrode active material layer was a square measuring 2.0 cm × 2.0 cm, and the positive electrode current collector was a rectangle measuring 2.0 cm × 3.0 cm (where the uncoated portion of the positive electrode active material layer was a rectangle measuring 2.0 cm × 1.0 cm). The cutting in the above (preparation of a first solid electrolyte layer) was performed so that the first solid electrolyte layer was a square measuring 2.0 cm × 2.0 cm. The cutting in the above (preparation of a laminate of a second solid electrolyte layer and a tabbed negative electrode current collector) was performed so that the second solid electrolyte layer was a square measuring 2.0 cm × 2.0 cm, and the negative electrode current collector was a rectangle measuring 2.0 cm × 3.0 cm (where the uncoated portion of the second solid electrolyte layer was a rectangle measuring 2.0 cm × 1.0 cm). A cell for evaluation in this comparative example was obtained in the same manner as in Example 1, except for the above.

[0053] [Comparative Example 2] An evaluation cell for this comparative example was obtained in the same manner as in Example 1, except that in the above (preparation of the first solid electrolyte layer), the thickness of the first solid electrolyte layer was set to 60 μm, and in the above (preparation of the laminate of the second solid electrolyte layer and the tab-attached negative electrode current collector), the second solid electrolyte layer was not formed on the negative electrode current collector. The thickness of the first solid electrolyte layer after CIP was 40 μm.

[0054] Comparative Example 3 The above (production of the first solid electrolyte layer) was carried out by the following method. In a glove box with an argon atmosphere having a dew point of −68° C. or less, an argyrodite-type sulfide solid electrolyte (Li ６ P.S. ５Eighty parts by weight of CI (average particle size (D50) 1 μm) and 20 parts by weight of polyvinylidene fluoride (PVdF) as a binder were dispersed in butyl acetate as a solvent to a solids content of 47% by weight. The binder was previously adjusted to a concentration of 6% by weight using butyl acetate. The resulting dispersion was stirred at 1000 rpm for 3 minutes using a planetary mixer to prepare a slurry. The resulting slurry was applied to SUS430 foil (10 μm thick) to a dry film thickness of 50 μm, and the solvent was dried on a hot plate at 80°C for 30 minutes. The SUS430 foil was peeled from the resulting laminate, and the laminate was cut into a 2.5 cm x 2.5 cm square to obtain a first solid electrolyte layer. A cell for evaluation of this comparative example was obtained using the same method as in Example 1, except for the above.

[0055] Comparative Example 4 The above (production of a laminate of a second solid electrolyte layer and a tab-attached negative electrode current collector) was carried out by the following method. In a glove box with an argon atmosphere having a dew point of −68° C. or less, an argyrodite-type sulfide solid electrolyte (Li ６ P.S. ５95 parts by mass of ethylenediaminetetraacetic acid (Ethylenediaminetetraacetic acid, average particle diameter 1 μm) and 5 parts by mass of polytetrafluoroethylene (PTFE) as a binder were mixed in an agate mortar and then kneaded for 2 minutes while applying shear force in the mortar. After confirming that the binder had fibrillated, the resulting kneaded mixture was sandwiched between two SUS430 foils (thickness 50 μm) and formed into a 200 μm thick sheet using a hand roller while heated on a hot plate at 80 °C. The sheet-shaped product sandwiched between the SUS foils was stretched to a thickness of 50 μm using a tabletop roll press equipped with a heating mechanism, with the roll surface temperature at 80 °C, while reducing the gap by 20 μm at a time. The resulting laminate was cut so that the second solid electrolyte layer was a square measuring 2.2 cm × 2.2 cm and the negative electrode current collector was a rectangle measuring 2.2 cm × 3.2 cm (with the uncoated portion of the second solid electrolyte layer being a rectangle measuring 2.2 cm × 1.0 cm). A tab lead (nickel-plated copper) was then welded to the uncoated portion of the negative electrode current collector where the second solid electrolyte layer was not coated, yielding a laminate of the second solid electrolyte layer and the negative electrode current collector with a tab. A cell for evaluation of this comparative example was obtained in the same manner as in Example 1, except for this.

[0056] Comparative Example 5 The above (production of the first solid electrolyte layer) was carried out by the following method. In a glove box with an argon atmosphere having a dew point of −68° C. or less, an argyrodite-type sulfide solid electrolyte (Li ６ P.S. ５Eighty parts by weight of 1,3,5-trimethylbenzene (average particle size (D50) 1 μm) of HCl and 20 parts by weight of styrene-butadiene rubber (SBR) as a binder were dispersed using 1,3,5-trimethylbenzene as a solvent to a solids content of 47% by weight. The binder was previously adjusted to a concentration of 6% by weight using 1,3,5-trimethylbenzene. The resulting dispersion was stirred at 1,000 rpm for 3 minutes using a planetary mixer to prepare a slurry. The resulting slurry was applied to SUS430 foil (10 μm thick) to a dry film thickness of 50 μm, and the solvent was dried on a hot plate at 80°C for 30 minutes. The SUS430 foil was peeled from the resulting laminate, and the laminate was cut into a 2.5 cm x 2.5 cm square to obtain a first solid electrolyte layer. A cell for evaluation of this comparative example was obtained using the same method as in Example 1, except for this.

[0057] <Example of Preparation of First Solid Electrolyte Layer for Evaluation> [Comparative Reference Example 1-1] In a glove box with an argon atmosphere having a dew point of −70° C. or less, an argyrodite-type sulfide solid electrolyte (Li ６ P.S. ５ Cl, average particle diameter (D50) 3 μm) was placed in a ceramic cylindrical tube jig (φ10.2 mm) and uniaxially press molded at 25° C. and 100 MPa to prepare a 50 μm-thick first solid electrolyte layer for evaluation.

[0058] Comparative Reference Example 1-2 In a glove box with an argon atmosphere having a dew point of −68° C. or less, an argyrodite-type sulfide solid electrolyte (Li ６ P.S. ５99 parts by mass of HCl (average particle size (D50) 3 μm) and 1 part by mass of polytetrafluoroethylene (PTFE) as a binder (the ratio of the binder amount to the solid content of the first solid electrolyte layer was 1% by mass) were mixed using an agate mortar and then kneaded for 2 minutes while applying shear force in the mortar. The resulting kneaded mixture was sandwiched between two SUS304 foils (thickness 50 μm) and formed into a sheet of 200 μm in thickness using a hand roller while heating on a hot plate at 80 °C. The sheet-shaped product sandwiched between the SUS foils was stretched to a thickness of 50 μm using a tabletop roll press equipped with a heating mechanism, with the roll surface temperature at 80 °C, while reducing the gap by 20 μm at a time, to obtain a first solid electrolyte layer for evaluation in this comparative example.

[0059] [Reference Examples 1-1 to 1-6 and Comparative Reference Example 1-3] A first solid electrolyte layer for evaluation in each example was obtained in the same manner as in Comparative Reference Example 1-2, except that the ratio of the binder amount to the solid content of the first solid electrolyte layer was changed as shown in Table 3 below.

[0060] <Charge / Discharge Test> The following charge / discharge test was performed on the evaluation cell prepared above. The charge / discharge test was performed while applying a restraining pressure of 3 MPa in the stacking direction of the evaluation cell using a pressure member. First, the evaluation cell was charged at 0.01 C for 5 seconds, and then placed in a thermostatic chamber at 60°C for 5 hours to bring the cell temperature to 60°C. The cell was charged at a constant current equivalent to 0.05 C, and when the cell voltage reached 4.2 V, the charging mode was switched to a constant voltage mode. After the current value reached 0.01 C, a 0.5-hour pause was performed. The cell was then discharged at a constant current equivalent to 0.05 C until the cell voltage reached 2.5 V, after which a 0.5-hour pause was performed. This cycle constitutes one cycle, and 10 charge / discharge cycles were performed. The charge capacity and discharge capacity at the first cycle were measured, and the percentage (%) of the discharge capacity relative to the charge capacity was calculated. The resulting value was used as the charge / discharge efficiency. The discharge capacity at the 10th cycle was measured, and the percentage (%) of the discharge capacity at the 10th cycle to the discharge capacity at the 1st cycle was calculated, and the obtained value was taken as the capacity retention rate. The results are shown in Tables 1 and 2 below.

[0061] <Short-circuit evaluation> The above charge-discharge test was performed five times, and the arithmetic mean value of the obtained charge-discharge efficiencies was taken as the average charge-discharge efficiency. Then, short-circuiting was evaluated based on the following criteria. The results are shown in Tables 1 and 2 below. ◯ (no short-circuit): average charge-discharge efficiency of 90% or more △ (slight short-circuit): average charge-discharge efficiency of 80% or more but less than 90% × (short-circuit): average charge-discharge efficiency of less than 80%.

[0062] <Evaluation of Handling Ease> The first solid electrolyte layer for evaluation prepared above and the first solid electrolyte layer prepared by the method described in the above Examples and Comparative Examples (Preparation of First Solid Electrolyte Layer) were subjected to a tensile test in accordance with JIS K 6251:2017 "Vulcanized rubber and thermoplastic rubber - Determination of tensile properties" to measure the breaking strength. The test specimens were dumbbell-shaped No. 6, and the measurement was performed at a pulling rate of 10 mm / min and room temperature (25°C). The handling ease was evaluated based on the following criteria. The first solid electrolyte layer for evaluation of Comparative Reference Example 1-1 did not have the strength required for a free-standing membrane, and was therefore evaluated as "× (poor)." The results are shown in Tables 2 and 3 below. ◯ (Good): Breaking strength of 0.2 N / mm ２ or more △ (insufficient): Breaking strength is 0.1 N / mm ２ 0.2N / mm or more ２ Less than × (bad): Breaking strength is 0.1 N / mm ２ Less than this or self-supporting film cannot be formed.

[0063] <Ion Conductivity Evaluation> The ion conductivity of the first solid electrolyte layer for evaluation prepared above was measured by the following method. In a glove box in an argon atmosphere with a dew point of −70° C. or less, the first solid electrolyte layer for evaluation was punched out to a diameter of 10 mm. The punched first solid electrolyte layer for evaluation was inserted into a ceramic cylindrical tube jig (φ10.2 mm) and uniaxially press-molded at 25° C. and 100 MPa to prepare a blocking cell of Al / first solid electrolyte layer for evaluation / Al. Note that, since a free-standing film could not be formed for the first solid electrolyte layer for evaluation in Comparative Reference Example 1-1, an argyrodite-type sulfide solid electrolyte (Li ６ P.S. ５A powder of Al / first solid electrolyte layer for evaluation / Al was placed in the cylindrical tube jig and uniaxially press-molded at 25°C and 100 MPa to produce a blocking cell of Al / first solid electrolyte layer for evaluation / Al. The blocking cell was subjected to electrochemical impedance spectroscopy (EIS) (measuring device: Solartron 1260) to measure impedance at an amplitude of 10 mV and from 1 MHz to 0.1 Hz. The resistance was calculated from the intercept with the X-axis in the Cole-Cole plot and normalized based on the cross-sectional area and thickness of the sample to determine the ionic conductivity. The relative values ​​of each ionic conductivity, relative to the ionic conductivity of Comparative Reference Example 1-1 (binder amount 0 mass%) set to 100, are shown in Table 3 below.

[0064]

[0065]

[0066]

[0067] The results shown in Tables 1 and 2 demonstrate that the present invention can further suppress short circuits in all-solid-state batteries including a solid electrolyte layer. Note that in Comparative Examples 3 and 5, the handleability (tensile strength) of the first solid electrolyte layer was insufficient, requiring a protective member or the like to prevent cracking or chipping of the outer periphery, and it was found that this may prevent short circuits from being suppressed without reducing the energy density.

[0068] REFERENCE SIGNS LIST 10a laminated secondary battery, 11' negative electrode current collector, 11" positive electrode current collector, 13 negative electrode active material layer, 14 positive electrode, 15 positive electrode active material layer, 17 solid electrolyte layer, 17a first solid electrolyte layer, 17b second solid electrolyte layer, 19 single cell layer, 21 power generating element, 25 negative electrode current collector, 27 positive electrode current collector, 29 laminate film.

Claims

1. a positive electrode having a positive electrode active material layer; a negative electrode having a negative electrode active material layer; a solid electrolyte layer interposed between the positive electrode and the negative electrode and containing a solid electrolyte; An all-solid-state battery comprising a power generating element having the solid electrolyte layer includes a first solid electrolyte layer adjacent to the positive electrode active material layer and including a first solid electrolyte and a first binder, and a second solid electrolyte layer adjacent to the negative electrode active material layer and including a second solid electrolyte and a second binder; the first binder includes at least one selected from the group consisting of polytetrafluoroethylene, carboxymethyl cellulose, polyethylene oxide, polyvinyl alcohol, and polyethylene; the second binder comprises at least one selected from the group consisting of styrene-butadiene rubber, polyvinylidene fluoride, polybutylene terephthalate, polyethylene terephthalate, carboxymethyl cellulose, polyethylene oxide, polyvinyl alcohol, polyethylene, polypropylene, polymethylpentene, polybutene, polyether nitrile, polyacrylonitrile, polyimide, polyamide, polyamideimide, ethylene-vinyl acetate copolymer, polyvinyl chloride, ethylene-propylene-diene copolymer, styrene-butadiene-styrene block copolymer, and styrene-isoprene-styrene block copolymer; when the power-generating element is viewed from above, at least a part of an outer peripheral edge of the positive electrode active material layer is located inside an outer peripheral edge of the first solid electrolyte layer or an outer peripheral edge of the second solid electrolyte layer, an outer circumferential edge of the first solid electrolyte layer being at least partially located outside an outer circumferential edge of the positive electrode active material layer and an outer circumferential edge of the negative electrode active material layer;

2. 2. The all-solid-state battery according to claim 1, wherein, in a plan view of the power generating element, at least a part of an outer peripheral edge of the second solid electrolyte layer is located more inward than an outer peripheral edge of the first solid electrolyte layer.

3. The all-solid-state battery according to claim 1 , wherein the first binder comprises polytetrafluoroethylene.

4. 4. The all-solid-state battery according to claim 3, wherein an amount of the polytetrafluoroethylene in the first solid electrolyte layer is 3 mass % or more and 50 mass % or less with respect to a total solid content contained in the first solid electrolyte layer.

5. The all-solid-state battery according to claim 1 , wherein the second binder includes styrene-butadiene rubber or polyvinylidene fluoride.

6. a positive electrode having a positive electrode active material layer; a negative electrode having a negative electrode active material layer; a solid electrolyte layer interposed between the positive electrode and the negative electrode and containing a solid electrolyte; An all-solid-state battery comprising a power generating element having the solid electrolyte layer includes a first solid electrolyte layer adjacent to the positive electrode active material layer and including a first solid electrolyte and a first binder, and a second solid electrolyte layer adjacent to the negative electrode active material layer and including a second solid electrolyte and a second binder; the first binder includes at least one selected from the group consisting of polytetrafluoroethylene, carboxymethyl cellulose, polyethylene oxide, polyvinyl alcohol, and polyethylene; the second binder comprises at least one selected from the group consisting of styrene-butadiene rubber, polyvinylidene fluoride, polybutylene terephthalate, polyethylene terephthalate, carboxymethyl cellulose, polyethylene oxide, polyvinyl alcohol, polyethylene, polypropylene, polymethylpentene, polybutene, polyether nitrile, polyacrylonitrile, polyimide, polyamide, polyamideimide, ethylene-vinyl acetate copolymer, polyvinyl chloride, ethylene-propylene-diene copolymer, styrene-butadiene-styrene block copolymer, and styrene-isoprene-styrene block copolymer; when the power-generating element is viewed from above, at least a part of an outer peripheral edge of the positive electrode active material layer is located inside an outer peripheral edge of the first solid electrolyte layer or an outer peripheral edge of the second solid electrolyte layer, an outer circumferential edge of the second solid electrolyte layer being located more inward than an outer circumferential edge of the first solid electrolyte layer when the power generating element is viewed from above;