All-solid-state rechargeable battery, stacked all-solid-state rechargeable battery, and method for manufacturing an all-solid-state rechargeable battery.

Abstract

The goal is to further improve the safety of all-solid-state rechargeable batteries compared to conventional batteries, while also simplifying the manufacturing process for all-solid-state rechargeable batteries and stacked all-solid-state rechargeable batteries as much as possible. [Solution] A solid-state secondary battery comprising: a positive electrode layer 10; solid electrolyte layers 30 laminated on both sides of the positive electrode layer; negative electrode layers 20 laminated on the sides of the solid electrolyte layer opposite to the side facing the positive electrode layer; an insulating member 13 arranged to cover the side end surface of the positive electrode layer; a foil-shaped first conductive member 41 protruding from the positive electrode layer through the insulating member to the outside; and a foil-shaped second conductive member 42 protruding from the negative electrode layer to the outside, wherein the first conductive member is integrally formed with the positive electrode layer, the second conductive member is integrally formed with the negative electrode layer, and the ends of the first conductive member and the second conductive member are laminated on the outside of the negative electrode layer while the first conductive member and the second conductive member are insulated from each other.

Description

[Technical Field]

[0001] This invention relates to an all-solid-state secondary battery, a stacked all-solid-state secondary battery, and a method for manufacturing an all-solid-state secondary battery. [Background technology]

[0002] All-solid-state rechargeable batteries are attracting increasing attention in recent years because they are expected to improve energy density compared to conventional lithium-ion batteries that use electrolytes. One way to further improve the energy density of these all-solid-state rechargeable batteries is to stack multiple single cells of the all-solid-state rechargeable battery to reduce the proportion of the outer casing in the overall battery.

[0003] For example, Patent Document 1 discloses a method for obtaining a stacked all-solid-state secondary battery by pressing a pair of roughened temporary battery bodies against a positive electrode current collector. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2017-157271 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, as the energy density of all-solid-state rechargeable batteries increases, if a short circuit occurs inside the battery due to external impact or penetration by a nail, for example, a large current will flow locally, potentially causing the all-solid-state rechargeable battery to overheat and catch fire.

[0006] This invention has been made in view of these problems, and aims to further improve the safety of all-solid-state secondary batteries compared to conventional batteries, while also simplifying the manufacturing process of all-solid-state secondary batteries and stacked all-solid-state secondary batteries as much as possible. [Means for solving the problem]

[0007] In other words, the all-solid-state secondary battery, the stacked all-solid-state secondary battery, and the methods for manufacturing them according to the present invention are as follows. [1] The positive electrode layer and Solid electrolyte layers are laminated on both sides of the positive electrode layer, A negative electrode layer is laminated on the side of the solid electrolyte layer opposite to the side facing the positive electrode layer, An insulating member arranged to cover the side end surface of the positive electrode layer, A foil-shaped first conductive member that extends from the positive electrode layer through the insulating member and protrudes to the outside, The negative electrode layer comprises a foil-shaped second conductive member that protrudes to the outside, The first conductive member is integrally formed with the positive electrode layer, The second conductive member is integrally formed with the negative electrode layer, A solid-state secondary battery in which the ends of the first current dispersant and the ends of the second current dispersant are stacked on the outside of the negative electrode layer in a state of mutual insulation. [2] Further comprising a foil-shaped first current collector that penetrates the insulating member from the positive electrode layer and protrudes to the outside, The all-solid-state secondary battery according to [1], wherein the first conductive member and the first current collector protrude in different directions from each other. [3] Further comprising a foil-shaped second current collector protruding from the negative electrode layer, The all-solid-state secondary battery according to [1] or [2], wherein the second conductive member and the second current collector protrude in different directions from each other. [4] The all-solid-state secondary battery according to any one of [1] to [3], further comprising a foil-shaped first current collector that protrudes outward from the positive electrode layer through the insulating member and a foil-shaped second current collector that protrudes outward from the negative electrode layer, wherein the first current collector and the second current collector protrude in different directions from each other. [5] The all-solid-state secondary battery according to any one of [1] to [4], wherein at least a portion of the side end face of the insulating member is a roughened portion. [6] The all-solid-state secondary battery according to any one of [1] to [5], wherein the insulating member contains resin. [7] The all-solid-state secondary battery according to any one of [1] to [6], wherein the insulating member contains an insulating filler. [8] The all-solid-state secondary battery according to [7], characterized in that the insulating filler consists of one or more substances selected from the group consisting of fibrous resin, resin nonwoven fabric, alumina, magnesium oxide, silica, boehmite, barium titanate, barium carbonate, yttria, and manganese oxide. [9] The first current collector, when viewed from the stacking direction, is provided so as to extend outward from one end of the positive electrode layer which is formed into a rectangular plate shape, The all-solid-state secondary battery according to any one of [1] to [8], wherein a part or all of the outer edge of the insulating member on the side where the current collector is located is located outside the outer edge of the negative electrode layer.

[10] The all-solid-state secondary battery according to any one of [1] to [9], wherein the solid electrolyte layer comprises a sulfide-based solid electrolyte containing lithium, phosphorus, and sulfur.

[11] An all-solid-state secondary battery according to any one of [1] to

[10] , comprising a negative electrode active material that forms an alloy with lithium and / or a negative electrode active material that forms a compound with lithium, wherein metallic lithium can be deposited inside the negative electrode layer during charging.

[12] The all-solid-state secondary battery according to

[11] , wherein 80% or more of the charging capacity of the negative electrode layer is provided by the deposited metallic lithium.

[13] The all-solid-state secondary battery according to any one of [1] to

[12] , wherein the negative electrode layer contains one or more selected from the group consisting of amorphous carbon, gold, platinum, palladium, silicon, silver, aluminum, bismuth, tin, and zinc. A stacked solid-state battery comprising two or more solid-state batteries described in any one of the items

[14] [1] to

[13] .

[15] The positive electrode layer and Solid electrolyte layers are laminated on both sides of the positive electrode layer, A negative electrode layer laminated on the surface of the solid electrolyte layer opposite to the surface facing the positive electrode layer, An insulating member disposed so as to cover the side end face of the positive electrode layer, A foil-shaped first conductive member protruding to the outside through the insulating member from the positive electrode layer, A foil-shaped second conductive member protruding to the outside from the negative electrode layer, and a laminate comprising: The first conductive member is integrally formed with the positive electrode layer, The second conductive member is integrally formed with the negative electrode layer, By folding the first conductive member and the second conductive member, A laminate preparation step of preparing a laminate in which an end portion of the first current dispersion body and an end portion of the second current dispersion body are laminated outside the negative electrode layer in a state of being insulated from each other; A pressing step of pressing the laminate in its lamination direction, and a method for manufacturing an all-solid-state secondary battery including the pressing step.

[16] The laminate includes a foil-shaped first current collector protruding from the positive electrode layer to the outside, A first current collector protection part for protecting the first current collector, After the pressing step, the manufacturing method of the all-solid-state secondary battery according to

[15] , further including a removing step of removing the first current collector protection part.

[17] The manufacturing method of the all-solid-state secondary battery according to

[16] , wherein the first current collector protection part is integrally formed on a side end face of the insulating member.

[18] The manufacturing method of the all-solid-state secondary battery according to

[17] , further including a step of forming a notch between the insulating member and the first current collector protection part to facilitate removal of the first current collector protection part.

[19] The manufacturing method of the all-solid-state secondary battery according to "18", wherein the notch is formed in a range of 5% or more and 99% or less of the thickness of the first current collector protection part.

Advantages of the Invention

[0008] According to the present invention, the battery comprises a first conductive member integrally formed with (i.e., electrically connected to) the positive electrode layer, and a second conductive member integrally formed with (i.e., electrically connected to) the negative electrode layer. Since the first and second conductive members are laminated on the outside of the negative electrode layer, even if a short circuit occurs in the all-solid-state secondary battery, the current can be distributed. As a result, the heat generated in the all-solid-state secondary battery due to localized current increases can be suppressed, and the safety of the all-solid-state secondary battery can be improved compared to conventional batteries.

[0009] Furthermore, since the first conductive member and the second conductive member are integrally formed with the positive electrode layer or the negative electrode layer, an all-solid-state secondary battery equipped with these conductive members can be easily manufactured by simply adding a step of folding the first conductive member and the second conductive member to the conventional process for manufacturing an all-solid-state secondary battery. [Brief explanation of the drawing]

[0010] [Figure 1] This is a cross-sectional view showing the schematic configuration of an all-solid-state secondary battery according to this embodiment. [Figure 2] This is a plan view showing the schematic configuration of an all-solid-state secondary battery according to this embodiment. [Figure 3] This is a cross-sectional view showing the schematic configuration of an all-solid-state secondary battery according to this embodiment. [Figure 4] This is a schematic diagram illustrating a method for manufacturing an all-solid-state secondary battery according to this embodiment. [Figure 5] Figure 4B is a plan view of the laminated structure as seen from the direction of its stacking. [Figure 6] This is a schematic diagram showing the structure of the surplus insulating material used in the all-solid-state secondary battery according to this embodiment. Figure 6A is a plan view seen from the stacking direction, and Figure 6B is a cross-sectional view taken along the CC line. [Figure 7] This is a schematic diagram illustrating a method for manufacturing an all-solid-state secondary battery according to this embodiment. [Figure 8] This is a schematic diagram illustrating a method for manufacturing an all-solid-state secondary battery according to this embodiment. [Figure 9]This is a schematic diagram illustrating a method for manufacturing an all-solid-state secondary battery according to this embodiment. [Figure 10] This is a cross-sectional view showing the schematic configuration of a stacked all-solid-state secondary battery according to this embodiment. [Figure 11] This is a cross-sectional view showing a schematic configuration of an all-solid-state secondary battery according to another embodiment of the present invention. [Figure 12] This graph shows the evaluation results of an all-solid-state secondary battery according to an embodiment of the present invention. [Figure 13] This graph shows the evaluation results of an all-solid-state secondary battery according to a comparative example of the present invention. [Figure 14] This graph shows the evaluation results of an all-solid-state secondary battery according to a comparative example of the present invention. [Modes for carrying out the invention]

[0011] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. In this specification and the drawings, components having substantially the same functional configuration are denoted by the same reference numerals to avoid redundant explanation. Also, the components in the figures have been enlarged or reduced as appropriate for the sake of clarity, and the size and proportions of the components in the figures may differ from those of the actual components.

[0012] <1. Basic configuration of the all-solid-state secondary battery according to this embodiment> The all-solid-state secondary battery 1 according to this embodiment comprises, for example, a positive electrode layer 10, a negative electrode layer 20, and a solid electrolyte layer 30, as shown in Figure 1. More specifically, it is an all-solid-state lithium secondary battery comprising a positive electrode layer 10, solid electrolyte layers 30 laminated on both sides of the positive electrode layer 10, negative electrode layers 20 laminated on the side of each solid electrolyte layer 30 opposite to the positive electrode layer 10, and an insulating member 13 arranged on the side end face S of the positive electrode layer 10. The side end face refers to the peripheral end of each layer that is not in the stacking direction of each layer, and means the end of each layer in a direction perpendicular to the stacking direction of each layer.

[0013] (1-1. Positive electrode layer) As shown in Figure 1, the positive electrode layer 10 includes a positive electrode current collector 11 and a positive electrode active material layer 12. Examples of the positive electrode current collector 11 include a plate-shaped or foil-shaped body made of stainless steel, titanium (Ti), nickel (Ni), aluminum (Al), or an alloy thereof. The thickness of the positive electrode current collector 11 is, for example, 1 μm or more and 50 μm or less, more preferably 5 μm or more and 30 μm or less. As shown in Figure 1, the positive electrode active material layer 12 is arranged on both sides of the positive electrode current collector 11. The positive electrode active material layer 12 contains at least a positive electrode active material and a solid electrolyte. The solid electrolyte contained in the positive electrode active material layer 12 may be the same type as the solid electrolyte contained in the solid electrolyte layer 30, or it may be a different type. Details of the solid electrolyte will be explained in the section on the solid electrolyte layer 30 below.

[0014] The positive electrode active material can be any positive electrode active material capable of reversibly intercepting and releasing lithium ions.

[0015] For example, the positive electrode active material may be in powder or granular form and can be formed using lithium salts such as lithium cobalt oxide (hereinafter referred to as LCO), lithium nickel oxide, lithium nickel cobalt oxide, lithium nickel cobalt aluminate (hereinafter referred to as NCA), lithium nickel cobalt manganese oxide (hereinafter referred to as NCM), lithium manganese oxide, lithium iron phosphate, nickel sulfide, copper sulfide, sulfur, iron oxide, or vanadium oxide. These positive electrode active materials may be used individually or in combination of two or more.

[0016] Further, the positive electrode active material is preferably formed by including a lithium salt of a transition metal oxide having a layered rock salt structure among the lithium salts described above. Here, "layered" represents a thin sheet-like shape. Also, "rock salt structure" represents a sodium chloride-type structure which is a kind of crystal structure. Specifically, it represents a structure in which the face-centered cubic lattices formed by each of the cations and anions are arranged so as to be shifted from each other by 1 / 2 of the edge of the unit lattice.

[0017] Examples of the lithium salt of the transition metal oxide having such a layered rock salt structure include, for example, LiNi x Co y Al z O2 (NCA), or LiNi x Co y Mn z O2 (NCM) (where 0 < x < 1, 0 < y < 1, 0 < z < 1, and x + y + z = 1), and the like, lithium salts of ternary transition metal oxides can be cited.

[0018] When the positive electrode active material contains a lithium salt of a ternary transition metal oxide having the above-described layered rock salt structure, the energy density and thermal stability of the all-solid-state secondary battery 1 can be improved.

[0019] The surface of the positive electrode active material may be covered by a coating layer. Here, the coating layer in the present embodiment may be any known coating layer for the positive electrode active material of the all-solid-state secondary battery 1. Examples of the coating layer include, for example, Li2O-ZrO2 and the like.

[0020] Also, when the positive electrode active material is formed of a lithium salt of a ternary transition metal oxide such as NCA or NCM and contains nickel (Ni) as the positive electrode active material, the capacity density of the all-solid-state secondary battery 1 can be increased, and the metal elution from the positive electrode active material in the charged state can be reduced. Thereby, the all-solid-state secondary battery 1 according to the present embodiment can improve the long-term reliability and cycle characteristics in the charged state.

[0021] Here, the shape of the positive electrode active material can be, for example, a perfect sphere or an ellipsoid. Furthermore, the particle size of the positive electrode active material is not particularly limited and should be within a range applicable to the positive electrode active material of conventional all-solid-state secondary batteries. In addition, the content of the positive electrode active material in the positive electrode layer 10 is not particularly limited and should be within a range applicable to the positive electrode layer 10 of a conventional all-solid-state secondary battery 1.

[0022] Furthermore, in addition to the positive electrode active material and solid electrolyte described above, the positive electrode active material layer 12 may appropriately contain additives such as conductive additives, binders, fillers, dispersants, and ion conduction aids.

[0023] Examples of conductive additives that can be incorporated into the positive electrode active material layer 12 include graphite, carbon black, acetylene black, Ketjenblack, carbon fiber, carbon nanotubes, graphene, and metal powders. Examples of binders that can be incorporated into the positive electrode active material layer 12 include styrene-butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, and polyethylene. Furthermore, known materials generally used in the electrodes of all-solid-state secondary batteries 1 can be used as fillers, dispersants, and ion conduction additives that can be incorporated into the positive electrode active material layer 12.

[0024] The thickness of the positive electrode active material layer 12 in the completed battery state is not particularly limited, but is preferably 20 μm or more and 1000 μm or less, more preferably 50 μm or more and 500 μm or less, and particularly preferably 100 μm or more and 300 μm or less.

[0025] (1-2. Negative electrode layer) The negative electrode layer 20 includes, for example, a plate-shaped or foil-shaped negative electrode current collector 21 and a negative electrode active material layer 22 formed on the negative electrode current collector 21, as shown in Figure 1. The negative electrode current collector 21 forms the outermost layer of the all-solid-state secondary battery 1 when the first conductive member and the second conductive member, described later, are not further laminated on its outside.

[0026] It is preferable that the negative electrode current collector 21 is made of a material that does not react with lithium, that is, a material that does not form either an alloy or a compound. In addition to stainless steel, other materials that can be used to make up the negative electrode current collector 21 include, for example, copper (Cu), titanium (Ti), iron (Fe), cobalt (Co), and nickel (Ni). The negative electrode current collector 21 may be composed of any one of these metals, or it may be composed of an alloy or clad material of two or more metals. Furthermore, the base metal may be plated or coated with other metals. The thickness of the negative electrode current collector 21 is, for example, 1 μm or more and 50 μm or less, more preferably 5 μm or more and 30 μm or less.

[0027] The negative electrode active material layer 22 includes, for example, at least one of a negative electrode active material that forms an alloy with lithium and a negative electrode active material that forms a compound with lithium. The negative electrode active material layer 22 may be configured such that metallic lithium can be deposited on one or both surfaces of the negative electrode active material layer 22, as described below.

[0028] Examples of the negative electrode active material include amorphous carbon, gold, platinum, palladium (Pd), silicon (Si) silver, aluminum (Al), bismuth (Bi), tin, antimony, and zinc. Examples of amorphous carbon include carbon black such as acetylene black, furnace black, and Ketjen black, as well as graphene.

[0029] The shape of the negative electrode active material is not particularly limited and may be granular, or it may be a uniform layer, such as a plating layer. In the former case, lithium ions or lithium pass through the interior of the granular negative electrode active material or through the gaps between the negative electrode active materials, forming a metal layer mainly composed of lithium between the negative electrode active material layer 22 and the negative electrode current collector 21, and some lithium exists within the negative electrode active material layer 22 by forming an alloy with metal elements in the negative electrode active material. On the other hand, in the latter case, the metal layer is deposited between the negative electrode active material layer 22 and the solid electrolyte layer 30.

[0030] Among those mentioned above, the negative electrode active material layer 22 has a specific surface area of ​​100 m² as amorphous carbon, as measured by nitrogen gas adsorption. 2 Low specific surface area amorphous carbon with a specific surface area of ​​300 m² or less, and specific surface area measured by nitrogen gas adsorption method. 2 It is preferable that the mixture contains a high specific surface area amorphous carbon with a value of 1 / g or more.

[0031] The negative electrode active material layer 22 may contain only one of these negative electrode active materials, or it may contain two or more negative electrode active materials. For example, the negative electrode active material layer 22 may contain only amorphous carbon as the negative electrode active material, or it may contain one or more selected from the group consisting of gold, platinum, palladium, silicon, silver, aluminum, bismuth, tin, antimony, and zinc. Alternatively, the negative electrode active material layer 22 may contain a mixture of one or more selected from the group consisting of gold, platinum, palladium, silicon, silver, aluminum, bismuth, tin, antimony, and zinc and amorphous carbon.

[0032] The mixing ratio (mass ratio) of amorphous carbon and the aforementioned metal such as gold is preferably about 1:1 to 1:3. By composing the negative electrode active material with these materials, the characteristics of the all-solid-state secondary battery 1 are further improved.

[0033] When using amorphous carbon along with one or more materials selected from the group consisting of gold, platinum, palladium, silicon, silver, aluminum, bismuth, tin, antimony, and zinc as the negative electrode active material, it is preferable that the particle size of these negative electrode active materials is 4 μm or less. In this case, the characteristics of the all-solid-state secondary battery 1 are further improved.

[0034] Furthermore, if the negative electrode active material is one or more materials selected from the group consisting of materials capable of forming an alloy with lithium, such as gold, platinum, palladium, silicon, silver, aluminum, bismuth, tin, antimony, and zinc, the negative electrode active material layer 22 may be a layer made of these metals. For example, this metal layer may be a plating layer.

[0035] The negative electrode active material layer 22 may further contain a binder as needed. Examples of this binder include styrene-butadiene rubber (SBR), polytetrafluoroethylene (PTFE), polyvinylidene fluoride, polyethylene oxide, etc. The binder may consist of one of these or two or more of these. By including the binder in the negative electrode active material layer 22 in this way, the detachment of the negative electrode active material can be suppressed, especially when the negative electrode active material is granular. The binder content in the negative electrode active material layer 22 is, for example, 0.3% by mass or more and 20.0% by mass or less, preferably 1.0% by mass or more and 15.0% by mass or less, and more preferably 3.0% by mass or more and 15.0% by mass or less, based on the total mass of the negative electrode active material layer 22.

[0036] Furthermore, the negative electrode active material layer 22 may contain additives used in conventional all-solid-state secondary batteries 1, such as fillers, dispersants, and ion conductive materials, as appropriate.

[0037] The thickness of the negative electrode active material layer 22 is not particularly limited, but if the negative electrode active material is granular, for example, the thickness in the completed battery state is 1 μm or more and 30 μm or less, preferably 5 μm or more and 20 μm or less. By setting the thickness to such a degree, the resistance value of the negative electrode active material layer 22 can be sufficiently reduced while fully obtaining the effects of the negative electrode active material layer 22 described above, and the characteristics of the all-solid-state secondary battery 1 can be sufficiently improved. On the other hand, the thickness of the negative electrode active material layer 22 is, for example, 1 nm to 100 nm when the negative electrode active material forms a uniform layer. In this case, the upper limit of the thickness of the negative electrode active material layer 22 is preferably 95 nm, more preferably 90 nm, and even more preferably 50 nm.

[0038] Furthermore, the present invention is not limited to the embodiments described above, and the negative electrode active material layer 22 can be any configuration available for use as the negative electrode active material layer 22 of the all-solid-state secondary battery 1. For example, the negative electrode active material layer 22 may be a layer containing the aforementioned negative electrode active material, a solid electrolyte, and a negative electrode layer conductive additive.

[0039] In this case, for example, a metal active material or a carbon active material can be used as the negative electrode active material. Examples of the metal active material include metals such as lithium (Li), indium (In), aluminum (Al), tin (Sn), and silicon (Si), as well as alloys thereof. Examples of the carbon active material include artificial graphite, graphite carbon fiber, resin-calcined carbon, pyrolysis vapor-grown carbon, coke, mesocarbon microbeads (MCMB), furfuryl alcohol resin-calcined carbon, polyacene, pitch-based carbon fiber, vapor-grown carbon fiber, natural graphite, and non-graphitizable carbon. These negative electrode active materials may be used individually or in combination of two or more types.

[0040] The conductive additive for the negative electrode layer and the solid electrolyte can use the same compounds as the conductive agent and the solid electrolyte contained in the positive electrode active material layer 12. Therefore, the description thereof here is omitted.

[0041] (1-3. Solid electrolyte layer) The solid electrolyte layer 30 is, for example, a layer formed between the positive electrode layer 10 and the negative electrode layer 20 as shown in FIG. 1, and contains a solid electrolyte. In the present embodiment, the solid electrolyte layer 30 is laminated between the positive electrode layer 10 and the negative electrode layer 20. Note that the Z direction (also referred to as the lamination direction) in the figure means the lamination direction of each layer, and the X direction means the direction perpendicular to the lamination direction. The thickness of the solid electrolyte layer 30 may be 5 μm or more and 100 μm or less in the state where the battery is completed. This thickness is preferably 8 μm or more and 80 μm or less, and more preferably 10 μm or more and 50 μm or less.

[0042] The solid electrolyte is, for example, in a powder form and is composed of, for example, a sulfide-based solid electrolyte material. Examples of the sulfide-based solid electrolyte material include Li2S-P2S5, Li2S-P2S5-LiX (X is a halogen element, for example, I, Br, Cl), Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2 S -SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (m, n are positive numbers, Z is any one of Ge, Zn or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO qExamples include (where p and q are positive numbers, and M is one of P, Si, Ge, B, Al, Ga, or In). Here, the sulfide-based solid electrolyte material is produced by processing the starting material (e.g., Li2S, P2S5, etc.) by a melt-quenching method or a mechanical milling method. Further heat treatment may be performed after these processes. The solid electrolyte may be amorphous, crystalline, or a mixture of both.

[0043] Furthermore, it is preferable to use a material as the solid electrolyte that contains sulfur and one or more elements selected from the group consisting of silicon, phosphorus, and boron, among the above-mentioned sulfide-based solid electrolyte materials. This improves the lithium conductivity of the solid electrolyte layer 30 and improves the battery characteristics of the all-solid-state secondary battery 1. In particular, it is preferable to use a solid electrolyte that contains sulfur (S), phosphorus (P), and lithium (Li) as constituent elements, and it is even more preferable to use one that contains Li2S-P2S5.

[0044] Here, when using a sulfide-based solid electrolyte material containing Li2S-P2S5 to form the solid electrolyte, the molar ratio of Li2S to P2S5 may be selected in the range of, for example, Li2S:P2S5 = 50:50 to 90:10. The solid electrolyte layer 30 may also contain a binder. Examples of binders included in the solid electrolyte layer 30 include styrene-butadiene rubber (SBR), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyethylene (PE), and polyacrylic acid (PAA). The binder included in the solid electrolyte layer 30 may be the same type as the binder in the positive electrode active material layer 12 and the negative electrode active material layer 22, or it may be a different type.

[0045] (1-4. Current collection section) As shown in Figures 1 and 2, the positive electrode layer 10 includes a positive electrode current collector portion 111 that protrudes laterally from the positive electrode current collector 11, and is connected to external wiring via this positive electrode current collector portion 111. Similarly, the negative electrode layer 20 includes a negative electrode current collector portion 211 that protrudes laterally from the negative electrode current collector 21, and is connected to external wiring via this negative electrode current collector portion 211. Figure 2 shows the all-solid-state secondary battery 1 according to this embodiment viewed from the Z direction (towards the second conductive member 42 shown in Figure 1), and Figure 1 is a cross-sectional view of this all-solid-state secondary battery 1 cut along line AA in Figure 2. In this specification, "lateral" refers, for example, to the direction extending outward from the outer edge of the positive electrode current collector 11 along its surface, and more specifically, to the direction perpendicular to the stacking direction of each layer constituting the all-solid-state secondary battery 1.

[0046] In this embodiment, the positive electrode current collector 111 is configured to penetrate the insulating member 13 and protrude outward from the insulating member 13. For the sake of explanation, in each figure, the direction in which the positive electrode current collector 111 protrudes is referred to as the X direction (also called the protrusion direction), and the direction perpendicular to the protrusion direction in a plan view of each layer constituting the all-solid-state secondary battery 1 as seen from the stacking direction is referred to as the Y direction (also called the width direction). In this embodiment, the positive electrode current collector 111 and the negative electrode current collector 211 are assumed to protrude substantially parallel to each other and to be of substantially the same length in the aforementioned protrusion direction. However, their protrusion direction and protrusion length may be the same or different. The positive electrode current collector 111 and the negative electrode current collector 211 may protrude in the same direction, but it is preferable that they protrude in different directions. In this embodiment, the positive electrode current collector 111 and the negative electrode current collector 211 protrude in opposite directions relative to their respective protrusion directions.

[0047] (1-5. Insulating materials) The insulating member 13 is arranged to closely adhere to the side end surface S of the positive electrode active material layer 12 of the positive electrode layer 10, for example, so as to cover the entire side end surface S of the positive electrode active material layer 12 of the positive electrode layer 10. This insulating member 13 is formed using an insulating material 13A, which is an electrically non-conductive material, and has a volume resistivity of 10 12 It is preferable that the density is Ω / cm or higher. Examples of materials constituting the insulating member material 13A include resin films containing resins such as polypropylene, polyethylene, or copolymers thereof. Examples of resins include polyolefin-based resin materials as described above, as well as vinyl-based resins such as polyvinyl chloride (PVC), acrylic-based resins such as polyacetal resin and polymethyl methacrylate (PMMA), polycarbonate (PC), polyamide-based resins, polyurethane resins, fluoropolymer-based resins such as polytetrafluoroethylene (PTFE), and composite resins of these listed above.

[0048] Such a resin film can be made to adhere closely to the positive electrode layer 10 and become less likely to peel off by, for example, pressure molding such as isotropic pressing. Furthermore, it is even better if the insulating material 13A is made by mixing insulating fillers into these resins. By including insulating fillers in the insulating material 13A, the adhesion between the insulating material 13A is improved, and the strength of the insulating material 13 can be improved when forming the insulating material 13 with the insulating material 13A and during use. In addition, by including insulating fillers together with the resin in the insulating material 13A, fine irregularities can be formed on the surface of the insulating material 13 by mixing in the insulating fillers. This irregular shape of the surface of the insulating material 13 makes it more difficult for the solid electrolyte layer 30 to peel off from the insulating material 13 when it is laminated. The insulating filler can be in various shapes, such as particulate, fibrous, needle-shaped, or plate-shaped. Among these, it is preferable to use fibrous or nonwoven fabric-shaped insulating fillers as they exhibit the above effects particularly prominently.

[0049] As the insulating filler, from the viewpoint of suppressing cost increases, it is preferable to use one or more substances selected from the group consisting of fibrous resin, resin nonwoven fabric, alumina, magnesium oxide, silica, boehmite, barium titanate, barium carbonate, yttria, and manganese oxide.

[0050] The thickness of the insulating member 13 in the completed battery is not particularly limited, but is preferably 20 μm to 1000 μm, more preferably 50 μm to 500 μm, and particularly preferably 100 μm to 300 μm. This preferred thickness varies depending on the thickness of the positive electrode layer 10, and the thickness of the insulating member 13 should be close to the thickness of the positive electrode layer 10. In this embodiment, when positive electrode active material layers 12 are formed on both sides of the positive electrode current collector 11, the insulating member 13 is also provided in two layers, similar to the positive electrode active material layers 12, so as to sandwich the positive electrode current collector 11 and the positive electrode current collector portion 111 from both sides. Preferably, the total thickness of the two insulating member layers 13 that sandwich the positive electrode current collector 11 and the positive electrode current collector portion 111 is approximately the same as the total thickness of the two positive electrode active material layers 12 formed on both sides of the positive electrode current collector 11.

[0051] <2. Characteristic Configuration of the All-Solid-State Secondary Battery According to This Embodiment> The all-solid-state secondary battery 1 according to this embodiment further comprises a first conductive member 41 and a second conductive member 42 that are electrically connected to the positive electrode layer 10 or the negative electrode layer 20.

[0052] In this embodiment, the first conductive member 41 is a conductive member for the positive electrode that is formed integrally with the positive electrode current collector 11.

[0053] The positive electrode conductive member 41 is electrically connected to the positive electrode current collector 11 and can disperse the current flowing through the all-solid-state secondary battery 1 in the event of a short circuit inside the battery due to external impact or penetration by a nail, etc. Its material and shape are not particularly limited, but given that it is integrally formed with the positive electrode current collector 11, it is preferably foil-shaped like the positive electrode current collector 11 and preferably made of the same material as the positive electrode current collector 11.

[0054] The positive electrode conductive member 41 is a foil-like member provided to extend outward from the positive electrode current collector 11 and is provided to penetrate the insulating member and protrude outward. The positive electrode conductive member 41 has, for example, a covering portion 411 which is substantially the same shape as the positive electrode current collector 11, and a connecting portion 412 which connects the covering portion 411 and the positive electrode current collector 11.

[0055] The covering portion 411 is the part that is stacked outside the negative electrode current collector 21 of the all-solid-state secondary battery 1 when the connecting portion 412 is folded, and covers the outer surface of the negative electrode current collector 21. It is preferable that the covering portion 411 is arranged to cover part or all of the negative electrode current collector 21 in the stacking direction of the all-solid-state secondary battery 1. Figure 3 shows a cross-sectional view of the all-solid-state secondary battery 1 after the connecting portion 412 has been folded and the all-solid-state secondary battery 1 is completed (cross-sectional view along line BB in Figure 2). As mentioned above, this covering portion 411 is integrally formed with the positive electrode current collector 11. In this embodiment, as will be described later, it is formed to extend from the positive electrode current collector 11, which is a rectangular metal foil. Therefore, from the viewpoint of suppressing breakage at the connecting portion and / or ease of manufacturing, it is preferable that the covering portion 411 is a metal foil of the same width as the positive electrode current collector 11. The shape and thickness of the covering portion 411 are not limited to those described above and can be changed as appropriate. It does not necessarily have to be the same thickness and shape as the positive electrode current collector 11, and it goes without saying that it can be made of various thicknesses and shapes as needed.

[0056] The connecting portion 412 is preferably formed from a strip of metal foil having the same width as the positive electrode current collector 11, similar to the covering portion 411, but it is not limited to this, and various shapes can be used.

[0057] In this embodiment, the second conductive member 42 is a negative electrode conductive member formed integrally with the negative electrode current collector 21. This second conductive member 42 is a foil-like member formed integrally with the negative electrode current collector 21 and protruding from the negative electrode current collector 21 to the outside. It is preferable that it has the same configuration (covering portion 421, connecting portion 422) and properties as the first conductive member 41 described above, but it is not limited to this, and various deformations are possible as long as it fulfills its function.

[0058] Furthermore, if the positive electrode conductive member 41 and the negative electrode conductive member 42 were to come into contact with each other, the positive electrode layer 10 and the negative electrode layer 20 would be short-circuited. Therefore, they are arranged so that they do not come into direct contact with each other. In order to reliably prevent them from coming into direct contact, it is preferable to provide an insulating layer 43 for conductive members between the positive electrode conductive member 41 and the negative electrode conductive member 42 to insulate them. This insulating layer 43 for conductive members may be, for example, an insulating sheet that covers both sides of the all-solid-state secondary battery 1 when it is in use, or a buffer material X that is placed in the outermost layer of the stacked all-solid-state secondary battery 100 or between each all-solid-state secondary battery when manufacturing the stacked all-solid-state secondary battery 100.

[0059] <3. Method for manufacturing an all-solid-state secondary battery according to this embodiment> Next, an example of a method and procedure for manufacturing the all-solid-state secondary battery 1 according to this embodiment will be described with reference to Figures 4 to 9. Figures 4, 7, 8, and 9 show cross-sectional views of the all-solid-state secondary battery during manufacturing, cut along line AA in Figure 2.

[0060] The method for manufacturing the all-solid-state secondary battery 1 according to this embodiment includes the following steps. (3-1. Fabrication of the positive electrode layer) The positive electrode active material layer 12 can be manufactured by mixing the materials constituting the positive electrode active material layer 12 (positive electrode active material, binder, etc.), stretching the mixture into a sheet, and then punching out the resulting positive electrode sheet into a specified shape such as a rectangle using a die-cutting machine. The laminate obtained by pressing the positive electrode active material layer 12 thus manufactured onto a positive electrode current collector 11, which is aluminum foil punched into a specified shape such as a rectangle, is called a positive electrode layer structure (Figure 4A). This positive electrode structure is placed on an aluminum plate covered with a PET film, and two insulating material 13A that form insulating members 13 are placed around the positive electrode structure, one on each side of the positive electrode active material layer 12. After placing another PET film on top of the whole, it is laminated and subjected to isostatic pressure treatment (isostatic press), thereby applying pressure from the lamination direction to produce the positive electrode layer insulating member composite 10A shown in Figure 4B.

[0061] Furthermore, during the aforementioned pressurization process, it is preferable that the aforementioned insulating material 13A includes a first current collector protection part (positive current collector protection part) 14 that encloses and protects the protruding portion of the positive current collector part 111, and as shown in Figure 4B, it is preferable that the entire positive current collector part 111 is covered from both sides by the positive current collector protection part 14.

[0062] The positive electrode current collector protection part 14 preferably has a surface area larger than the area of ​​the positive electrode current collector part 111 so that it can cover the entire positive electrode current collector part 111 without any gaps, at least while isotropic pressure is applied, and its shape is not particularly limited. From the viewpoint of ease of manufacture, the positive electrode current collector protection part 14 is preferably formed integrally with the insulating member 13, as shown in Figure 5, and is a rectangular plate shape with the same width and thickness as the insulating member 13, protruding from the insulating member 13 in the same direction as the positive electrode current collector part 111 and larger than the positive electrode current collector part 111. For clarity, dashed lines are shown between the insulating member 13 and the positive electrode current collector protection part 14 in each drawing.

[0063] As mentioned above, not only the positive electrode current collector 111 but also the positive electrode conductive member 41 extends from the positive electrode current collector 11. Therefore, it is preferable that the insulating member material 13A includes a first conductive member protection part (positive electrode conductive member protection part) 15 that encloses and protects the positive electrode conductive member 41, and it is preferable that the entire positive electrode conductive member 41 is covered from both sides by the positive electrode conductive member protection part 15. The positive electrode conductive member protection portion 15 is preferably the same size as or larger than the positive electrode conductive member 41, so as shown in Figure 8C, for example, it can cover the entire positive electrode conductive member 41 without any gaps, at least while isotropic pressure is applied, and its shape is not particularly limited. From the viewpoint of ease of manufacture, the positive electrode conductive member protection portion 15 is preferably formed integrally with the insulating member 13, as shown in Figure 5, and is a rectangular plate shape with the same width and thickness as the insulating member 13, protruding from the insulating member 13 in the same direction as the positive electrode conductive member 41. For clarity, dashed lines are shown between the insulating member 13 and the positive electrode conductive member protection portion 15 in each drawing.

[0064] In this embodiment, two insulating material 13A as shown in Figures 6A and 6B are prepared, and as shown in Figure 4B, these two insulating material 13A are arranged so that both sides of the positive electrode current collector 111 are sandwiched by the positive electrode current collector protection part 14, and both sides of the positive electrode conductive member 41 are sandwiched by the positive electrode conductive member protection part 15, and then pressure treatment is performed by isostatic pressure.

[0065] (3-2. Fabrication of the negative electrode layer) The negative electrode active material layer coating solution is prepared by adding the materials constituting the negative electrode active material layer 22 (negative electrode active material, binder, etc.) to a polar or non-polar solvent. Then, as shown in Figure 7A, the obtained negative electrode active material layer coating solution is applied to the negative electrode current collector 21 and dried. The negative electrode layer 20 is prepared by punching it out into a rectangular plate shape using a die or the like. As mentioned above, the negative electrode current collector portion 211 and the negative electrode conductive member 42 extend from the negative electrode current collector 21.

[0066] (3-3. Preparation of the solid electrolyte layer) The solid electrolyte layer 30 can be made from a solid electrolyte formed from a sulfide-based solid electrolyte material. The method for making the solid electrolyte is as follows.

[0067] First, the starting material is processed using methods such as melt-and-quench method or mechanical milling. For example, when using the melt-and-cool method, a sulfide-based solid electrolyte material can be produced by mixing a predetermined amount of starting materials (e.g., Li2S, P2S5, etc.), forming them into pellets, reacting them in a vacuum at a predetermined reaction temperature, and then rapidly cooling them. The reaction temperature of the Li2S and P2S5 mixture is preferably 400°C to 1000°C, more preferably 800°C to 900°C. The reaction time is preferably 0.1 hours to 12 hours, more preferably 1 hour to 12 hours. Furthermore, the rapid cooling temperature of the reactants is usually 10°C or lower, preferably 0°C or lower, and the rapid cooling rate is usually about 1°C / sec to 10000°C / sec, more preferably about 1°C / sec to 1000°C / sec.

[0068] Furthermore, when using the mechanical milling method, sulfide-based solid electrolyte materials can be produced by stirring and reacting the starting materials (e.g., Li2S, P2S5, etc.) using a ball mill or the like. While the stirring speed and time in the mechanical milling method are not particularly limited, a faster stirring speed can increase the rate of sulfide-based solid electrolyte material production, and a longer stirring time can increase the conversion rate of the raw materials to sulfide-based solid electrolyte material.

[0069] Subsequently, the mixed raw materials obtained by the melt-quenching method or the mechanical milling method can be heat-treated at a predetermined temperature and then pulverized to produce particulate solid electrolytes. If the solid electrolyte has a glass transition temperature, it may change from amorphous to crystalline upon heat treatment.

[0070] Next, a solid electrolyte layer coating solution is prepared containing the solid electrolyte obtained by the above method, other additives such as a binder, and a dispersion medium. As the dispersion medium, a general-purpose nonpolar solvent such as xylene or diethylbenzene can be used. Alternatively, a polar solvent that is relatively unreactive with the solid electrolyte can be used. The concentrations of the solid electrolyte and other additives can be appropriately adjusted according to the composition of the solid electrolyte layer 30 to be formed and the viscosity of the liquid composition.

[0071] The aforementioned liquid composition of the solid electrolyte is coated onto a PET film whose surface has been treated for mold release using a blade, and after drying, a solid electrolyte sheet is produced in which a solid electrolyte layer 30 is formed on the PET film.

[0072] (3-4.Lamination process) As described above, a solid electrolyte sheet punched out to the same or a larger shape as the negative electrode layer 20 is laminated to one side of the negative electrode layer 20, as shown in Figure 7A. These are then pressed together under isotropic pressure to create a tight bond between the negative electrode layer 20 and the solid electrolyte layer 30, as shown in Figure 7B. If the solid electrolyte layer 30 is larger than the negative electrode layer 20, any portion of the solid electrolyte layer 30 that protrudes outward when laminated on the negative electrode layer 20 can be removed. This laminated structure will be referred to as the electrolyte negative electrode structure 20A.

[0073] Next, as shown in Figure 8A, the aforementioned positive electrode layer insulating material composite 10A is laminated so as to be sandwiched between two electrolyte negative electrode structures 20A from both sides. At this time, the electrolyte negative electrode structures 20A are laminated so that the solid electrolyte layer 30 of the electrolyte negative electrode structure 20A is in contact with both sides of the positive electrode layer 10, and the whole assembly is laminated and pressed under isotropic pressure to produce the uncut all-solid-state secondary battery 1A shown in Figure 8B.

[0074] During this isotropic pressing, in order to protect the aforementioned negative electrode current collector 211 and negative electrode conductive member 42, the insulating member material 13A further comprises a second current collector protection section (negative electrode current collector protection section) 16 and a second conductive section protection section (negative electrode conductive section protection section) 17, as shown in Figure 6, which support the negative electrode current collector 211.

[0075] The negative electrode current collector protection part 16 preferably has a larger area than the negative electrode current collector 211 so that it can support the entire negative electrode current collector 211, at least while isotropic pressure is applied, as shown in Figure 8B, and its shape is not particularly limited. From the viewpoint of ease of manufacture, the negative electrode current collector protection part 16 is preferably formed integrally with the insulating member 13, as shown in Figure 5, and is a rectangular plate shape with the same width and thickness as the insulating member 13, protruding from the insulating member 13 in the same direction as the negative electrode current collector 211. For clarity, dashed lines are shown between the insulating member 13 and the negative electrode current collector protection part 16 in each drawing.

[0076] As shown in Figure 8C, the negative electrode conductive member protection portion 17 preferably has the same area as or a larger area than the negative electrode conductive member 42 so that it can support the entire negative electrode conductive member 42 at least while isotropic pressure is applied, and its shape is not particularly limited. From the viewpoint of ease of manufacture, the negative electrode conductive member protection portion 17 is preferably formed integrally with the insulating member 13, as shown in Figure 5, and is a rectangular plate shape with the same width and thickness as the insulating member 13, protruding from the insulating member 13 in the same direction as the negative electrode conductive member 42. For clarity, dashed lines are shown between the insulating member 13 and the negative electrode conductive member protection portion 17 in each drawing.

[0077] In Figures 1, 8B, and 8C, there appear to be gaps between the negative electrode current collector 211 and the insulating material 13A, and between the negative electrode conductive member 42 and the insulating material 13A. However, when the materials are laminated, there are actually almost no gaps between them, and when pressurized, the negative electrode current collector 211 and the negative electrode conductive member 42 are pressed against the insulating material 13A and supported by the insulating material 13A from one side.

[0078] It is preferable that the outer edge 1E of the insulating member 13 is positioned so that a part or all of its outer edge 1E is located outside the outer edge 2E of the negative electrode layer 20 in the direction in which the positive electrode current collector 111 and / or negative electrode current collector 211 protrude. Furthermore, it is preferable that the negative electrode layer 2 is laminated so that its outer edge 2E is located on the insulating member 13, because even if the negative electrode layer 20 is pressed against the positive electrode layer 10 and deformed by external pressure, a short circuit due to physical contact between the positive electrode layer 10 and the negative electrode layer 20 can be suppressed.

[0079] The outer edge 1E of the insulating member 13 refers to the outermost edge (outer edge) of the side end face of the insulating member 13 in a direction perpendicular to the lamination direction, as shown in Figures 1 and 2. Similarly, the outer edge 2E of the negative electrode layer 20 refers to the outermost edge (outer edge) of the side end face of the negative electrode layer 20 in a direction perpendicular to the lamination direction. In this embodiment, for example, it refers to the outermost edge of the side end face of the negative electrode current collector 21 or the negative electrode active material layer 22 in a direction perpendicular to the lamination direction. In this embodiment, since the covering portion 421 of the negative electrode conductive member 42 has the same shape as the negative electrode layer 20, the outer edge of the negative electrode conductive member 42 in Figure 2 directly represents the outer edge 2E of the negative electrode layer 20.

[0080] (3-5. Isostatic Press) The pressurization process using the isostatic press (pressurization step) described above will be explained below. Isotropic pressing is performed by placing a support plate, such as a SUS plate, on at least one side of the laminate. This isotropic pressing allows each laminate forming the positive electrode layer insulating member composite 10A, the electrolyte negative electrode structure 20A, or the all-solid-state secondary battery 1 to be subjected to pressure treatment from the direction of lamination.

[0081] Examples of pressure media for isotropic presses include liquids such as water and oil, and powders. Using a liquid as the pressure media is more preferable. The pressure in the isotropic press is not particularly limited, but can be, for example, 10 to 1000 MPa, preferably 100 to 500 MPa. The pressurizing time is also not particularly limited, and can be, for example, 1 to 120 minutes, preferably 5 to 30 minutes. Furthermore, the temperature of the pressure medium during pressurization is also not particularly limited, and can be, for example, 20 to 200°C, preferably 50 to 100°C. Furthermore, during isotropic pressing, it is preferable that the laminate constituting the all-solid-state secondary battery 1, together with the support plate, be laminated with a resin film or the like to isolate it from the external atmosphere.

[0082] Compared to other pressing methods such as roll pressing, isotropic pressing is advantageous in that it suppresses cracking in each layer constituting the all-solid-state secondary battery 1, prevents warping of the all-solid-state secondary battery 1, and enables high-pressure pressing that is not affected by the increase in electrode area.

[0083] Subsequently, the all-solid-state secondary battery 1B before folding is obtained by removing one or more of the excess portions, which are the positive electrode current collector protection portion 14, the negative electrode current collector protection portion 16, the positive electrode conductive member protection portion 15, and the negative electrode conductive member protection portion 17, from the all-solid-state secondary battery 1A before cutting. Figures 8B and 8C show the all-solid-state secondary battery 1A before cutting, and Figures 9A and 9B show the all-solid-state secondary battery 1B before folding. In Figures 9A and 9B, the insulating member 13 is formed from two insulating member materials 13A, but these insulating member materials 13A may be, for example, heated and integrated together.

[0084] At this time, for example, as shown in Figure 6B, it is preferable to make cuts 13C in the thickness direction between the insulating member 13 and the positive electrode current collector protection part 14 and the negative electrode current collector protection part 16, as this makes them easier to remove. Furthermore, it is preferable that the ends of the cuts 13C penetrate the insulating member 13 for easier removal. It is also preferable that these cuts are formed between the insulating member 13 and the positive electrode conductive member protection part 15 and the negative electrode conductive member protection part 17. The method for removing the positive electrode current collector protection part 14 and the negative electrode current collector protection part 16 is not limited to those described above; for example, they may be removed using tools or machinery instead of by hand. The positive electrode conductive member protection part 15 and the negative electrode conductive member protection part 17 may also be removed in a similar manner. By removing the positive electrode current collector protection part 14, etc., from the insulating member material 13A in this way, a rougher portion (roughened portion) is formed on the side end face of the insulating member 13 compared to the rest of the insulating member material 13A, due to the removal of the positive electrode current collector protection part 14, etc.

[0085] Finally, the all-solid-state secondary battery 1 shown in Figures 1 to 3 is completed by folding the positive electrode conductive member 41 and the negative electrode conductive member 42 so that at least a portion of them is stacked on the outside of the negative electrode current collector 21. At this time, both the positive electrode conductive member 41 and the negative electrode conductive member 42 are positioned on the outside of one of the negative electrode current collectors 21 of the all-solid-state secondary battery 1. When the positive electrode conductive member 41 is folded, there is a possibility that a portion of the side surface of the positive electrode conductive member 41 may come into contact with the negative electrode current collector 21 or the negative electrode active material layer, causing a short circuit. Therefore, in this embodiment, a second insulating member 44 is provided between the side end surface of the negative electrode current collector 21 and the negative electrode active material layer 22, which may come into contact with the side surface of the positive electrode conductive member 41, and the side surface of the positive electrode conductive member 41. This second insulating member 44 can be formed, for example, by placing an insulating seal or the like on the side end faces of the negative electrode current collector 21 and the negative electrode active material layer 22 before bending the positive electrode conductive member 41. Furthermore, when the negative electrode conductive member 42 is folded, a portion of the side surface of the negative electrode conductive member 42 may come into contact with the side end of the folded positive electrode conductive member 41, potentially causing a short circuit. Therefore, it is preferable to provide a third insulating member 45 between the side surface of the negative electrode conductive member 42 and the side end of the positive electrode conductive member 41. In this case, it can be formed by placing an insulating seal or the like at the end of the positive electrode conductive member 41. It is preferable that the second insulating member 44 and the third insulating member 45 are arranged to cover the entire side end face of the negative electrode current collector 21, the negative electrode active material layer 22, and the positive electrode conductive member 41 in a direction different from the protruding direction.

[0086] <4. Effects of the all-solid-state secondary battery according to this embodiment> According to the all-solid-state secondary battery 1 of this embodiment, since it is equipped with a positive electrode conductive member 41 and a negative electrode conductive member 42 which are integrally formed with the positive electrode current collector 11 and the negative electrode current collector 21, even if an internal short circuit occurs between the positive electrode layer 10 and the negative electrode layer 20 of the all-solid-state secondary battery 1 due to external impact or penetration by a conductive object such as a nail, the short-circuit current can be distributed to these positive electrode conductive member 41 and negative electrode conductive member 42, thereby suppressing heat generation in the all-solid-state secondary battery 1 and preventing ignition or explosion. Furthermore, the positive electrode conductive member 41 and the negative electrode conductive member 42 are integrally molded with the positive electrode current collector 11 or the negative electrode current collector 21. This allows for the manufacture of an all-solid-state secondary battery 1 equipped with the positive electrode conductive member 41 and the negative electrode conductive member 42 using almost the same procedure as in the conventional method, without the need for complicated operations such as welding of multi-layer metal foils that would occur if the conductive members were used separately.

[0087] <5. Method for manufacturing a stacked all-solid-state secondary battery according to this embodiment> A stacked all-solid-state secondary battery 100 can be manufactured by stacking multiple all-solid-state secondary batteries 1 manufactured in the manner described above. The positive electrode conductive member 41 and negative electrode conductive member 42 provided in each all-solid-state secondary battery 1 may be arranged separately for each all-solid-state secondary battery 1, or, as shown in Figure 10, the positive electrode conductive member 41 and negative electrode conductive member 42 of multiple stacked all-solid-state secondary batteries 1 may be gathered together at one or more locations in the stacking direction. When stacking all-solid-state secondary batteries 1 in this manner, the positive electrode current collectors 111 and negative electrode current collectors 211 of the multiple all-solid-state secondary batteries 1 are aligned in the stacking direction and then pressed or welded to create electrical conductivity between the positive electrode current collectors 111 and negative electrode current collectors 211 of each all-solid-state secondary battery 1.

[0088] <6. Charging and discharging of the all-solid-state secondary battery according to this embodiment> The charging and discharging of the all-solid-state secondary battery 1 according to this embodiment will be described below. In the all-solid-state secondary battery 1 according to this embodiment, during the initial stages of charging, lithium is absorbed into the negative electrode active material layer 22 by the negative electrode active material forming an alloy or compound with lithium ions within the negative electrode active material layer 22. Subsequently, after exceeding the charging capacity provided by the negative electrode active material layer 22, metallic lithium is deposited on one or both surfaces of the negative electrode active material layer 22, forming a metallic lithium layer. Since the metallic lithium is formed by diffusion through the negative electrode active material capable of forming alloys or compounds, it is not dendritic but is mainly formed uniformly between the negative electrode active material layer 22 and the negative electrode current collector 21. During discharge, metallic lithium is ionized from the negative electrode active material layer 22 and the metallic lithium layer and moves to the positive electrode active material layer 12 side. As a result, metallic lithium itself can be used as the negative electrode active material, improving the energy density.

[0089] This deposition of metallic lithium occurs by composing the negative electrode active material with a specific substance, namely a substance that forms an alloy or compound with lithium. During discharge, the lithium in the negative electrode active material layer 22 and the metallic lithium layer is ionized and moves to the positive electrode layer 10. Therefore, metallic lithium can be used as the negative electrode active material in the all-solid-state secondary battery 1. More specifically, if the charging capacity of the negative electrode layer 20 (the total charging capacity provided by the negative electrode active material layer 22 and the aforementioned metallic lithium layer) is set to 100%, it is preferable that 80% or more of that charging capacity is provided by the metallic lithium layer.

[0090] Furthermore, it is preferable that the metallic lithium layer is formed between the negative electrode active material layer 22 and the negative electrode current collector 21, that is, inside the negative electrode layer 20. In this case, the negative electrode active material layer 22 covers the metallic lithium layer, so the negative electrode active material layer 22 functions as a protective layer for the metallic lithium layer. This is preferable because it suppresses short circuits and capacity degradation of the all-solid-state secondary battery 1, and consequently improves the characteristics of the all-solid-state secondary battery 1.

[0091] One method for enabling the deposition of metallic lithium in the negative electrode active material layer 22 is to make the charging capacity of the positive electrode active material layer 12 greater than the charging capacity of the negative electrode active material layer 22. Specifically, it is preferable that the ratio (capacity ratio) of the charging capacity of the positive electrode active material layer 12 to the charging capacity of the negative electrode active material layer 22 satisfies the requirements of the following formula (1). 0.002 a: Charging capacity of the positive electrode active material layer 12 (mAh) b: Charging capacity of the negative electrode active material layer 22 (mAh)

[0092] ​When the capacity ratio represented by formula (1) is greater than 0.002, the negative electrode active material layer 22 can sufficiently mediate the deposition of metallic lithium from lithium ions, regardless of the configuration of the negative electrode active material layer 22, making it easier for the metallic lithium layer to be formed properly. Furthermore, when the metallic lithium layer is formed between the negative electrode active material layer 22 and the negative electrode current collector 21, the negative electrode active material layer 22 can function sufficiently as a protective layer, which is preferable. For this reason, the capacity ratio is more preferably 0.01 or higher, and even more preferably 0.03 or higher.

[0093] Furthermore, when the above capacity ratio is less than 0.5, the negative electrode active material layer 22 does not store most of the lithium during charging, making it easier to uniformly form the metallic lithium layer regardless of the configuration of the negative electrode active material layer 22. The above capacity ratio is more preferably 0.2 or less, and even more preferably 0.1 or less.

[0094] It is more preferable that the capacity ratio is greater than 0.01. If the capacity ratio is 0.01 or less, the characteristics of the all-solid-state secondary battery 1 may deteriorate. This is because the negative electrode active material layer 22 may not function adequately as a protective layer. For example, if the thickness of the negative electrode active material layer 22 is very thin, the capacity ratio may be 0.01 or less. In this case, repeated charging and discharging may cause the negative electrode active material layer 22 to disintegrate, and dendrites may precipitate and grow. As a result, the characteristics of the all-solid-state secondary battery 1 may deteriorate. Furthermore, it is more preferable that the capacity ratio is less than 0.5. If the capacity ratio is 0.5 or more, the amount of lithium deposited in the negative electrode layer 20 may decrease, which may reduce the battery capacity. For similar reasons, it is more preferable that the capacity ratio is less than 0.25. In addition, by having a capacity ratio of less than 0.25, the output characteristics of the battery can also be further improved.

[0095] Here, the charging capacity of the positive electrode active material layer 12 is obtained by multiplying the charging ratio capacity (mAh / g) of the positive electrode active material by the mass of the positive electrode active material in the positive electrode active material layer 12. If multiple types of positive electrode active materials are used, the value of charging ratio × mass should be calculated for each positive electrode active material, and the sum of these values ​​should be taken as the charging capacity of the positive electrode active material layer 12. The charging capacity of the negative electrode active material layer 22 is calculated in the same way. That is, the charging capacity of the negative electrode active material layer 22 is obtained by multiplying the charging ratio capacity (mAh / g) of the negative electrode active material by the mass of the negative electrode active material in the negative electrode active material layer 22. If multiple types of negative electrode active materials are used, the value of charging ratio capacity × mass should be calculated for each negative electrode active material, and the sum of these values ​​should be taken as the capacity of the negative electrode active material layer 22. Here, the charging ratio capacity of the positive electrode active material and the negative electrode active material is the capacity estimated using an all-solid-state half-cell with lithium metal as the counter electrode. In practice, the charging capacity of the positive electrode active material layer 12 and the negative electrode active material layer 22 is directly measured using an all-solid-state half-cell.

[0096] The following methods can be used to directly measure the charging capacity. First, the charging capacity of the positive electrode active material layer 12 is measured by fabricating an all-solid-state half-cell using the positive electrode active material layer 12 as the working electrode and Li as the counter electrode, and performing CC-CV charging from the OCV (open circuit voltage) to the upper limit charging voltage. This upper limit charging voltage is defined in the JIS C 8712:2015 standard, and for positive electrode active material layers 12 using lithium cobalt oxide-based positive electrode active materials, it is 4.25V, and for positive electrode active material layers 12 using other positive electrode active materials, it refers to the voltage obtained by applying the provisions of A.3.2.3 (safety requirements when applying different upper limit charging voltages) of JIS C 8712:2015. The charging capacity of the negative electrode active material layer 22 is measured by fabricating an all-solid-state half-cell using the negative electrode active material layer 22 as the working electrode and Li as the counter electrode, and performing CC-CV charging from the OCV (open circuit voltage) to 0.01V.

[0097] The charge ratio capacity is calculated by dividing the charge capacity measured in this way by the mass of each active material. The charge capacity of the positive electrode active material layer 12 may be the initial charge capacity measured during the first charging cycle.

[0098] <7. Other Embodiments of the Invention> The all-solid-state secondary battery according to the present invention is not limited to those described above. As mentioned above, two second conductive members may extend from the negative electrode layer, or, as shown in Figure 11, only one second conductive member may extend from the negative electrode layer.

[0099] The solid electrolyte layer 30 provided between the positive electrode layer and the negative electrode layer only needs to be stacked in at least one layer, but may be stacked in two, three, four or more layers.

[0100] This invention is not limited to all-solid-state lithium-ion secondary batteries, but can be broadly applied to all-solid-state secondary batteries that have a foil-shaped current collector and are manufactured by molding them using a pressurized process such as isostatic pressing. [Examples]

[0101] The present invention will be described in more detail below with further specific examples, but it goes without saying that the present invention is not limited to these. (Example 1) [Fabrication of positive electrode layer structure] LiNi as a positive electrode active material 0.8 Co 0.15 Mg 0.05O2(NCM) was used. This active material was coated with Li2O-ZrO2. As the solid electrolyte, Li6PS5Cl, an argyrodite-type crystal, was prepared. As the binder, polytetrafluoroethylene (Teflon® binder manufactured by DuPont) was prepared. In addition, carbon nanofiber (CNF) was prepared as a conductive additive. These materials were then mixed in a mass ratio of positive electrode active material:solid electrolyte:conductive additive:binder = 85:15:3:1.5, and the mixture was stretched into a sheet to produce a positive electrode sheet. This positive electrode sheet was then punched into a specified shape using a die-cutting machine. The positive electrode current collector 11 was made from 10 μm thick aluminum foil coated with a 1 μm thick undercoat layer, punched into a specified shape using a Pinnacle Die®. The positive electrode current collector 11 was rectangular in shape and was integrally molded with a rectangular conductive component for the positive electrode.

[0102] The positive electrode current collector and positive electrode active material layer were placed on a PET film with a release treatment on its surface (hereinafter referred to as "release film"). Two insulating material 13A were then positioned such that the ring-shaped portion of the positive electrode current collector 111 surrounded the positive electrode active material layer 12, and the positive electrode current collector protection portion 14 protruded from the positive electrode current collector 11, while the positive electrode conductive member protection portion 15 sandwiched the positive electrode conductive member from both sides. After this, the package was covered with another release film, and then covered from both sides with a SUS metal plate (support material) that was 0.3 mm thick and had the same shape as the combined ring-shaped portion of the positive electrode active material layer and insulating material 13A, that is, the positive electrode current collector protection portion 14 and the positive electrode conductive member protection portion 15 of the insulating material 13A were not covered. Finally, the package was vacuum laminated. The insulating member 13 portion of the insulating member material 13A was integrated with the positive electrode current collector 11 and the positive electrode active material layer 12 by submerging it in a pressurized medium and performing hydrostatic pressure treatment (consolidation process by isostatic pressing) at 490 MPa.

[0103] A positive electrode layer insulating member composite 10A is defined as a positive electrode layer insulating member composite 10A comprising a positive electrode layer 10 in which a positive electrode active material layer 12 is laminated on both sides of the positive electrode current collector 11, a positive electrode protective part, an insulating member 13 that covers the side circumferential surface (side end face S) different from the lamination direction of the positive electrode active material layer 12, a positive electrode current collector protective part 14, and a positive electrode conductive member protective part 15.

[0104] The insulating material 13A mentioned above was manufactured by punching out an insulating resin film with a Pinnacle Die (registered trademark). The insulating resin film used in this embodiment is a polycarbonate material, Excure (registered trademark), manufactured by AGC Inc. As shown in Figure 6A, the insulating material 13A has a ring-shaped insulating material 13A with a housing hole just large enough to surround the positive electrode active material layer 12 from its periphery, and four extensions extending outwards in all directions. Rectangular current collector protection parts 14 and 16 that protect the current collector parts (111, 211) extend in opposite directions from each other, and rectangular conductive member protection parts 15 and 17 that protect the first conductive member and the second conductive member extend in opposite directions from each other, in a direction different from the direction in which the current collector protection parts 14 and 16 extend.

[0105] [Fabrication of the negative electrode layer] As the negative electrode current collector 21, a nickel-plated copper foil current collector with a total thickness of 11 μm, plated with nickel to a thickness of 0.5 μm on both sides, was prepared. This negative electrode current collector 21 is integrally formed with the conductive member for the negative electrode. In addition, as the negative electrode active material, Asahi Carbon Co., Ltd.'s CB1 (nitrogen adsorption specific surface area is approximately 339 m2 / g, DBP oil supply amount is approximately 193 ml / 100g), Asahi Carbon Co., Ltd.'s CB2 (nitrogen adsorption specific surface area is approximately 52 m2 / g, DBP oil supply amount is approximately 193 ml / 100g), and silver particles with a particle size of 60 nm were prepared. The particle size of these silver particles can be measured using, for example, the median diameter (so-called D50) measured using a laser particle size distribution system. Next, 1.5g of CB1, 1.5g of CB2, and 1g of silver particles were placed in a container, and 4g of an N-methylpyrrolidone (NMP) solution containing 5% by mass of binder (Kureha Corporation #9300) was added. Then, a total of 30g of NMP was gradually added to this mixed solution while stirring, thereby preparing a negative electrode active material layer coating solution. This negative electrode active material layer coating solution was applied onto the aforementioned negative electrode current collector 21 using a blade coater and dried in air at 80°C for about 20 minutes to form a negative electrode active material layer 22. The resulting laminate was vacuum dried at 100°C for about 12 hours and punched out with a Pinnacle Die (registered trademark). The negative electrode layer 20 was prepared by the above process.

[0106] [Preparation of solid electrolyte sheets] First, a solid electrolyte layer coating solution was prepared. A primary mixed slurry was prepared by adding an SBR binder dissolved in dehydrated xylene to a Li2S-P2S5 (80:20 mol%) amorphous powder, which is a sulfide-based solid electrolyte, in an amount of 1% by mass relative to the solid electrolyte. A secondary mixed slurry was then prepared by adding appropriate amounts of dehydrated xylene and dehydrated diethylbenzene to this primary mixed slurry to adjust the viscosity. Furthermore, to improve the dispersibility of the mixed powder, 5 mm diameter zirconia balls were added to the tertiary mixed slurry so that the space, mixed powder, and zirconia balls each occupied 1 / 3 of the total volume of the mixing container. The resulting tertiary mixture was then added to a rotary-orbit mixer and stirred at 3000 rpm for 3 minutes to prepare a solid electrolyte layer coating solution. The prepared solid electrolyte layer coating solution was applied to a PET film with a release-treated surface using a blade, dried on a hot plate at 40°C for 10 minutes, and then vacuum-dried at 40°C for 12 hours to obtain a solid electrolyte sheet. The thickness of the solid electrolyte layer after drying was approximately 65 μm. The dried solid electrolyte sheet was punched out with a die-cutting blade and processed to the desired size.

[0107] [Fabrication of electrolyte anode structures] A solid electrolyte sheet was placed on the surface of the negative electrode layer 20 so that the solid electrolyte layer 30 and the negative electrode active material layer 22 were in contact. These were then placed on a 3 mm thick aluminum plate (support material) with a release film attached, and the entire assembly, including the support material, was vacuum laminated. By immersing the assembly in a pressurized medium and performing hydrostatic pressure treatment (consolidation process by isostatic pressing) at 50 MPa, the solid electrolyte layer on the solid electrolyte sheet became integrated with the negative electrode layer 20. This will be referred to as the electrolyte negative electrode structure 20A.

[0108] [Fabrication of all-solid-state secondary batteries] A laminate, which is a pre-pressurized all-solid-state secondary battery, was obtained by placing a positive electrode layer insulating material composite 10A between two electrolyte negative electrode structures 20A on a release film. This laminate was further covered with a release film and then covered on both sides with a 0.3 mm thick SUS metal plate (support material) of the same shape as used in the [fabrication of the positive electrode layer] above, and then vacuum laminate packing was performed including the support material. It was submerged in a pressurized medium and subjected to hydrostatic pressure treatment (consolidation process by isostatic pressing) at 490 MPa to obtain a pre-cut all-solid-state secondary battery 1A. Finally, the positive electrode current collector protection part and the negative electrode current collector protection part were cut from the pre-cut all-solid-state secondary battery 1A to obtain a single cell (single cell) of the pre-folded all-solid-state secondary battery 1B. In this embodiment, aluminum plates and stainless steel metal plates are used as support materials, but any material with sufficient strength to withstand isotropic pressure treatment can be used for these support materials.

[0109] [Stacking of all-solid-state secondary batteries] Six 300 μm thick resin films were prepared, and five fabricated solid-state secondary batteries were placed one by one between these resin films and stacked. Then, the conductive members on the positive and negative electrode sides of each single cell were all folded toward one side of the stacking direction of the solid-state secondary battery cells, so that the positive and negative electrode conductive members were gathered and stacked at one end of the stacked solid-state secondary battery. At this time, a 25 μm thick polyimide film was inserted between these conductive members to insulate them from direct electrical contact. An aluminum (Al) tab was ultrasonically welded to the positive electrode current collector and a nickel (Ni) tab was ultrasonically welded to the negative electrode current collector, and then the stacked solid-state secondary battery 100 was obtained by vacuum lamination packing.

[0110] [Charge / Discharge Evaluation of All-Solid-State Rechargeable Batteries] The fabricated stacked solid-state secondary battery was sandwiched between 1 mm insulating sheets from the outside in the stacking direction, and then sandwiched between two metal plates from the outside. Screws with disc springs were passed through holes pre-drilled in the metal plates, and the screws were tightened to fasten the stacked solid-state secondary battery with an applied pressure of 1.0 MPa. The battery characteristics were evaluated using a charge / discharge evaluation device TOSCAT-3100 under the charge / discharge conditions of charging at 45°C with a constant current of 0.1C up to an upper voltage limit of 4.25V, then charging at a constant voltage until the current became 0.05C, and discharging at 0.1C until the termination voltage was 2.5V. The results are shown in Figure 12.

[0111] [Nail-piercing test] A nail-penetration test was performed on a stacked solid-state secondary battery using a nail-penetration test apparatus. Specifically, a stacked solid-state secondary battery, charged using the same procedure as described above for charge-discharge evaluation, was removed from the metal plate, placed and fixed on a bakelite plate with a φ10 mm hole, and the stability of the stacked solid-state secondary battery was evaluated by inserting a nail (φ3 mm, tip angle 36 degrees) at a speed of 50 mm / sec from the side where the conductive material is stacked toward the stacking direction. The results are shown in Table 1.

[0112] (Example 2) In a subsequent experiment, an all-solid-state secondary battery was fabricated using the same method as in Example 1, except that an insulating material was used that had only positive electrode current collector protection and negative electrode current collector protection, and did not have positive electrode conductive member protection or negative electrode conductive member protection. As a result, after pressure molding of the all-solid-state secondary battery, there were cases where the positive electrode conductive member and negative electrode conductive member physically detached from the positive electrode current collector and negative electrode current collector.

[0113] (Comparative Example 1) A laminated all-solid-state secondary battery was fabricated using the same method as in Example 1, except that the insulating material used in Example 2 was used, and a positive electrode current collector without a positive electrode conductive member and a negative electrode current collector without a negative electrode conductive member were used. The battery was then subjected to the nail-piercing test described above. The results are shown in Table 1. The results from the [Charge / Discharge Evaluation of All-Solid-State Secondary Battery] are shown in Figure 13.

[0114] (Comparative Example 2) A stacked solid-state secondary battery was fabricated using the same method as in Comparative Example 1. Subsequently, six 11 μm thick nickel-plated copper foils were used on the positive electrode side and six on the negative electrode side as independent conductive members that were not integrally molded with the current collector. These were then welded to the positive or negative electrode current collector using ultrasonic welding and resistance welding to fabricate a stacked solid-state secondary battery with conductive members. Although welding was possible, the conductive members and current collectors were made of different materials, and the large total number of metal foils used resulted in a thick weld, making welding between the current collector and the conductive members difficult, and some welding defects were observed. This stacked solid-state secondary battery of Comparative Example 2 was subjected to the nail-piercing test described above. The results are shown in Table 1. Furthermore, the results from the [Charge / Discharge Evaluation of Solid-State Secondary Batteries] described above are shown in Figure 14.

[0115] [Table 1]

[0116] (Discussion of the results) As shown in Table 1, the stacked all-solid-state secondary battery using the all-solid-state secondary battery according to the embodiment equipped with a conductive material for the positive electrode and a conductive material for the negative electrode showed reduced heat generation in the all-solid-state secondary battery during the nail-insertion test, resulting in no thermal runaway, ignition, or fire. On the other hand, in the case of the stacked all-solid-state secondary battery using the all-solid-state secondary battery according to Comparative Example 1, which does not have conductive members for the positive electrode and the negative electrode, the nail-insertion test resulted in the all-solid-state secondary battery exploding. Furthermore, in the all-solid-state secondary battery and stacked all-solid-state secondary battery of Comparative Example 2, which were manufactured using positive electrode conductive members and negative electrode conductive members that are not integrated with the positive electrode current collector or negative electrode current collector, it is necessary to weld the positive electrode current collector to the positive electrode conductive member and the negative electrode current collector to the negative electrode conductive member during the manufacturing process. In this case, it was found that welding can be difficult depending on the combination of materials used for each current collector and each conductive member, and that the thickness increases due to the presence of multiple welding points, making welding difficult. As shown in Figure 12, the stacked all-solid-state secondary battery fabricated in Example 1 exhibited good charge-discharge characteristics, and it was confirmed that it achieved charge-discharge characteristics equivalent to those of the all-solid-state secondary battery in Comparative Example 1 shown in Figure 13 (i.e., an all-solid-state secondary battery without conductive materials for the positive electrode and negative electrode). Similar results were obtained for the all-solid-state secondary battery in Comparative Example 2. From these results, it can be seen that the difference in performance of the stacked all-solid-state secondary batteries in the nail-insertion test between the example and the comparative example is due to the presence or absence of conductive materials and whether or not the conductive materials are integrally molded. Furthermore, a comparison of Example 1 and Example 2 revealed that using an insulating material equipped with a conductive member protection portion for the positive electrode and / or a conductive member protection portion for the negative electrode is preferable because it makes the manufacturing of all-solid-state secondary batteries and stacked all-solid-state secondary batteries easier. [Explanation of symbols]

[0117] 100 stacked all-solid-state secondary batteries 1 All-solid-state secondary battery 10 Positive electrode layer 11 Positive electrode current collector 111 Positive electrode current collector 12 Cathode active material layer 13 Insulating material 13C cut 14 1st current collector protection section 16 2nd current collector protection section 20 Negative electrode layer 21 Negative electrode current collector 211 Negative electrode current collector 22 Negative electrode active material layer 30 Solid electrolyte layer 41 First conductive member 42 Second conductive member

Claims

1. The positive electrode layer, Solid electrolyte layers are laminated on both sides of the positive electrode layer, A negative electrode layer is laminated on the side of the solid electrolyte layer opposite to the side facing the positive electrode layer, An insulating member arranged to cover the side end surface of the positive electrode layer, A foil-shaped first conductive member that extends from the positive electrode layer through the insulating member and protrudes to the outside, The negative electrode layer comprises a foil-shaped second conductive member that protrudes to the outside, The first conductive member is integrally formed with the positive electrode layer, The second conductive member is integrally formed with the negative electrode layer, A solid-state secondary battery in which the first conductive member and the second conductive member are insulated from each other, and the ends of the first conductive member and the ends of the second conductive member are laminated on the outside of the negative electrode layer.

2. The positive electrode layer further comprises a foil-shaped first current collector that penetrates the insulating member and protrudes to the outside, The all-solid-state secondary battery according to claim 1, wherein the first conductive member and the first current collector protrude in different directions from each other.

3. The negative electrode layer further comprises a foil-shaped second current collector that protrudes to the outside, The all-solid-state secondary battery according to claim 1, wherein the second conductive member and the second current collector protrude in different directions from each other.

4. A foil-shaped first current collector portion that penetrates the insulating member from the positive electrode layer and protrudes to the outside, A foil-shaped second current collector protruding from the negative electrode layer, Furthermore, The all-solid-state secondary battery according to claim 1, wherein the first current collector and the second current collector protrude in different directions from each other.

5. The all-solid-state secondary battery according to claim 1, wherein at least a portion of the side end surface of the insulating member is a roughened portion.

6. The all-solid-state secondary battery according to claim 1, wherein the insulating member contains resin.

7. The all-solid-state secondary battery according to claim 1, wherein the insulating member contains an insulating filler.

8. The all-solid-state secondary battery according to claim 7, wherein the insulating filler consists of one or more substances selected from the group consisting of fibrous resin, resin nonwoven fabric, alumina, magnesium oxide, silica, boehmite, barium titanate, barium carbonate, yttria, and manganese oxide.

9. The first current collector is provided so as to extend outward from one end of the positive electrode layer, The all-solid-state secondary battery according to claim 2, wherein a part or all of the outer edge of the insulating member on the side where the first current collector is located, when viewed from the stacking direction, is located outside the outer edge of the negative electrode layer.

10. The all-solid-state secondary battery according to claim 1, wherein the solid electrolyte layer comprises a sulfide-based solid electrolyte containing lithium, phosphorus, and sulfur.

11. The all-solid-state secondary battery according to claim 1, comprising one or more negative electrode active materials selected from negative electrode active materials that form an alloy with lithium and negative electrode active materials that form a compound with lithium, wherein metallic lithium can be deposited inside the negative electrode layer during charging.

12. The all-solid-state secondary battery according to claim 11, wherein 80% or more of the charging capacity of the negative electrode layer is provided by the deposited metallic lithium.

13. The all-solid-state secondary battery according to claim 1, wherein the negative electrode layer contains one or more selected from the group consisting of amorphous carbon, gold, platinum, palladium, silicon, silver, aluminum, bismuth, tin, and zinc.

14. A stacked solid-state secondary battery comprising two or more stacked solid-state secondary batteries according to any one of claims 1 to 13.

15. The positive electrode layer, Solid electrolyte layers are laminated on both sides of the positive electrode layer, A negative electrode layer is laminated on the side of the solid electrolyte layer opposite to the side facing the positive electrode layer, An insulating member arranged to cover the side end surface of the positive electrode layer, A foil-shaped first conductive member that extends from the positive electrode layer through the insulating member and protrudes to the outside, A laminate comprising a foil-shaped second conductive member protruding to the outside from the negative electrode layer, The first conductive member is integrally formed with the positive electrode layer, The second conductive member is integrally formed with the negative electrode layer, The first conductive member and the second conductive member are folded, A laminate preparation step is to prepare a laminate in which the end of the first conductive member and the end of the second conductive member are laminated on the outside of the negative electrode layer, with the first conductive member and the second conductive member insulated from each other. A method for manufacturing an all-solid-state secondary battery, comprising a pressurization step of applying pressure to the laminate from the direction of stacking.

16. The laminate comprises a foil-shaped first current collector portion that protrudes outward from the positive electrode layer, The system includes a first current collector protection unit that protects the first current collector unit, A method for manufacturing an all-solid-state secondary battery according to claim 15, further comprising a removal step of removing the first current collector protection part after the pressurization step.

17. The method for manufacturing an all-solid-state secondary battery according to claim 16, wherein the first current collector protection portion is integrally formed with the side end face of the insulating member.

18. The method for manufacturing an all-solid-state secondary battery according to claim 17, further comprising the step of forming a notch between the insulating member and the first current collector protective part to facilitate removal of the first current collector protective part.

19. The method for manufacturing an all-solid-state secondary battery according to claim 18, wherein the notch is formed in a range of 5% to 99% of the thickness of the first current collector protective portion.

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