Electrode laminate

Abstract

To suppress current concentration at the boundary between a positive electrode active material layer and an insulating member in a positive electrode of a battery, and localized deposition of lithium on the negative electrode side containing metallic lithium or a lithium alloy.SOLUTION: In an electrode laminate 1, a solid electrolyte layer 30 has a low ion conductive region 31 in a region from the boundary line between a positive electrode active material layer 20 and an insulating member 50 to a distance A in one direction perpendicular to the thickness direction of the solid electrolyte layer 30 and to a distance B in the other direction, and the positive electrode active material layer 20 includes an inclined portion 20a that is inclined such that its width narrows in a direction away from a positive electrode current collector 10, and the distance A and the distance B satisfy the following relational expression (1): distance A=distance B, distance A≤distance B, distance A≥distance B (1)SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing an electrode stack. [Background technology]

[0002] Batteries such as all-solid-state batteries are manufactured, for example, by applying an electrode mixture onto a positive electrode current collector to form a positive electrode active material layer, and then further forming an insulating member on the outer periphery of the positive electrode active material layer, and then cutting out a sheet having a solid electrolyte disposed on the upper surface of the positive electrode active material layer from the sheet into an arbitrary shape, stacking the positive electrodes and negative electrodes alternately, and press-molding the resulting sheet.

[0003] In the positive electrode of the battery obtained in this manner, the positive electrode active material layer has an inclined portion that is inclined so as to widen toward the positive electrode current collector (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-173954 Summary of the Invention [Problem to be solved by the invention]

[0005] When the positive electrode active material layer has an inclined portion that is inclined so as to widen toward the positive electrode current collector, current concentrates at the boundary between the positive electrode active material layer and the insulating member, causing localized deposition of lithium on the negative electrode side containing metallic lithium or a lithium alloy, which is a problem.

[0006] In order to solve the above-mentioned problems, the present application aims to suppress current concentration at the boundary between the positive electrode active material layer and the insulating member in the positive electrode of a battery, and to suppress localized lithium deposition on the negative electrode side containing metallic lithium or a lithium alloy, thereby contributing to energy efficiency. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides the following means. [1] An electrode laminate that utilizes a deposition-dissolution reaction of metallic lithium as a negative electrode reaction, a positive electrode current collector, a positive electrode active material layer, a solid electrolyte layer, and a negative electrode current collector; an insulating member is disposed on the outer periphery of the positive electrode active material layer; the solid electrolyte layer has a low ion-conductivity region in which the ion conductivity of the solid electrolyte is lower than the ion conductivity of the solid electrolyte in a central portion of the solid electrolyte layer, in a region extending from a boundary line between the positive electrode active material layer and the insulating member to a distance A in one direction perpendicular to the thickness direction of the solid electrolyte layer, and in a region extending from a boundary line between the positive electrode active material layer and the insulating member to a distance B in the other direction perpendicular to the thickness direction of the solid electrolyte layer, the positive electrode active material layer has an inclined portion that is inclined so that its width narrows in a direction away from the positive electrode current collector, The electrode stack, wherein the distance A and the distance B satisfy the following relational expression (1): Distance A = Distance B, Distance A ≤ Distance B, Distance A ≥ Distance B (1)

[0008] The electrode laminate of the present invention can suppress current concentration at the boundary between the positive electrode active material layer and the insulating member, and can suppress localized deposition of lithium on the negative electrode for an all-solid-state battery containing metallic lithium or a lithium alloy.

[0009] [2] The electrode stack according to [1], wherein a first contact portion where the inclined portion and the solid electrolyte layer contact each other has a high proportion of the low ion conductive region in a distance from a second contact portion where the inclined portion and the positive electrode current collector contact each other to a point on the solid electrolyte layer when a straight line is drawn in the stacking direction.

[0010] The electrode laminate of the present invention can suppress current concentration at the boundary between the positive electrode active material layer and the insulating member, and can suppress localized deposition of lithium on the negative electrode for an all-solid-state battery containing metallic lithium or a lithium alloy.

[0011] [3] The electrode stack according to [1], wherein the distance A is 500 μm or less and the distance B is 500 μm or less.

[0012] The electrode laminate of the present invention can suppress current concentration at the boundary between the positive electrode active material layer and the insulating member, and can suppress localized deposition of lithium on the negative electrode for an all-solid-state battery containing metallic lithium or a lithium alloy. [Effects of the Invention]

[0013] According to the present invention, it is possible to suppress current concentration at the boundary between the positive electrode active material layer and the insulating member in the positive electrode of a battery, and to suppress localized deposition of lithium on the negative electrode side containing metallic lithium or a lithium alloy. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a cross-sectional view showing an example of an electrode stack according to an embodiment of the present invention. [Figure 2] FIG. 10 is a diagram showing the results of a simulation of the current density of an electrode stack according to an embodiment of the present invention. [Figure 3] FIG. 2 is a cross-sectional view showing an example of an electrode stack in an experimental example. [Figure 4] 10 is a diagram showing the results of simulating the current density of the solid electrolyte layer in Experimental Example 1. FIG. [Figure 5] 10 is a diagram showing the results of simulating the current density of the solid electrolyte layer in Experimental Example 2. FIG. [Figure 6] FIG. 10 is a diagram showing the results of simulating the current density of the solid electrolyte layer in Experimental Example 3. [Figure 7] FIG. 10 is a diagram showing the results of simulating the current density of the solid electrolyte layer in Experimental Example 4. [Figure 8] FIG. 10 is a diagram showing the results of simulating the current density of the solid electrolyte layer in Experimental Example 5. [Figure 9] FIG. 10 is a diagram showing the results of simulating the current density of the solid electrolyte layer in Experimental Example 6. [Figure 10] FIG. 10 is a diagram showing the results of simulating the current density of the solid electrolyte layer in Experimental Example 7. [Figure 11] FIG. 10 is a diagram showing the results of simulating the current density of the solid electrolyte layer in Experimental Example 8. [Figure 12] FIG. 10 is a diagram showing the results of simulating the current density of the solid electrolyte layer in Experimental Example 9. [Figure 13] FIG. 10 is a diagram showing the results of simulating the current density of the solid electrolyte layer in Experimental Example 10. [Figure 14] FIG. 10 is a diagram showing the results of simulating the current density of the solid electrolyte layer in Experimental Example 11. [Figure 15] FIG. 13 is a diagram showing the results of simulating the current density of the solid electrolyte layer in Experimental Example 12. [Figure 16] FIG. 13 is a diagram showing the results of simulating the current density of the solid electrolyte layer in Experimental Example 13. [Figure 17] FIG. 11 is a diagram showing the results of simulating the current density of the solid electrolyte layer in Experimental Example 14. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an electrode stack according to one embodiment of the present invention will be described with reference to the drawings.

[0016] [Electrode laminate] 1 is a cross-sectional view showing an example of an electrode laminate according to an embodiment of the present invention. Note that the drawings used in the following description may show characteristic portions enlarged for convenience in order to make the characteristics easier to understand, and the dimensional ratios of the components are not limited to those shown.

[0017] 1, the electrode laminate 1 includes a positive electrode current collector 10, a positive electrode active material layer 20, a solid electrolyte layer 30, and a negative electrode current collector 40. In the electrode laminate 1, the positive electrode current collector 10, the positive electrode active material layer 20, the solid electrolyte layer 30, and the negative electrode current collector 40 are laminated.

[0018] A positive electrode active material layer 20 is formed on one main surface 10a of the positive electrode current collector 10. The positive electrode active material layer 20 has an inclined portion 20a that is inclined so that its width narrows in a direction away from one main surface 10a of the positive electrode current collector 10 (toward the thickness direction of the positive electrode active material layer 20). The angle of the inclined portion 20a with respect to one main surface 10a of the positive electrode current collector 10 is not particularly limited and is adjusted depending on the capacity of the positive electrode active material layer 20, the thickness of the solid electrolyte layer 30, etc. In this embodiment, the current density of the electrode stack 1 is derived by simulation, and the angle of the inclined portion 20a with respect to one main surface 10a of the positive electrode current collector 10 is adjusted based on the results of the simulation.

[0019] An insulating member 50 is disposed on the outer periphery of the positive electrode active material layer 20 . The insulating member 50 has an inclined portion that is inclined so as to widen toward one main surface 10a of the positive electrode current collector 10 (toward the thickness direction of the positive electrode current collector 10). The angle of the inclined portion with respect to one main surface 10a of the positive electrode current collector 10 is not particularly limited and is adjusted depending on the capacity of the positive electrode active material layer 20, the thickness of the solid electrolyte layer 30, etc.

[0020] The solid electrolyte layer 30 has a low ion-conductive region 31 in which the ionic conductivity of the solid electrolyte is lower than that of the solid electrolyte in the central portion of the solid electrolyte layer 30, in a region extending from the boundary between the positive electrode active material layer 20 and the insulating member 50 to a distance A in one direction perpendicular to the thickness direction of the solid electrolyte layer 30 (to the right of the boundary between the positive electrode active material layer 20 and the insulating member 50 in FIG. 1 ), and in a region extending from the boundary between the positive electrode active material layer 20 and the insulating member 50 to a distance B in the other direction perpendicular to the thickness direction of the solid electrolyte layer 30 (to the left of the boundary between the positive electrode active material layer 20 and the insulating member 50 in FIG. 1 ). The solid electrolyte layer 30 also has a high ion-conductive region 32 in which the ionic conductivity of the solid electrolyte is higher than that of the solid electrolyte in the central portion of the solid electrolyte layer 30, located closer to the periphery than the low ion-conductive region 31.

[0021] The distance A and the distance B satisfy the following relational expression (1). Distance A = Distance B, Distance A ≤ Distance B, Distance A ≥ Distance B (1)

[0022] The distance A is preferably 500 μm or less, and the distance B is preferably 500 μm or less.

[0023] In the first contact portion 61 where the inclined portion 20a and the solid electrolyte layer 30 contact each other, the proportion of the low ion conductive region 31 is higher than that of the high ion conductive region 32 in the distance from the second contact portion 62 where the inclined portion 20a and the positive electrode current collector 10 contact each other to a point on the solid electrolyte layer 30 when a straight line is drawn in the stacking direction.

[0024] (positive electrode) The positive electrode current collector 10 is preferably made of at least one material with high electrical conductivity. Examples of highly conductive materials include metals or alloys containing at least one of silver (Ag), palladium (Pd), gold (Au), platinum (Pt), aluminum (Al), copper (Cu), chromium (Cr), and nickel (Ni), as well as non-metals such as carbon (C). Considering not only high conductivity but also manufacturing costs, aluminum, nickel, or stainless steel is preferred. Furthermore, aluminum is less likely to react with the positive electrode active material, negative electrode active material, and solid electrolyte. Therefore, using aluminum for the positive electrode current collector 10 can reduce the internal resistance of the electrode stack 1.

[0025] Examples of the shape of the positive electrode current collector 10 include foil, plate, mesh, nonwoven fabric, and foam. In order to improve adhesion to the positive electrode active material layer 20, carbon or the like may be disposed on the surface of the positive electrode current collector 10, or the surface may be roughened.

[0026] The positive electrode active material layer 20 contains a positive electrode active material that donates and receives lithium ions and electrons. The positive electrode active material is not particularly limited as long as it is a material that can reversibly release and absorb lithium ions and transport electrons, and known positive electrode active materials that can be used in the positive electrode of all-solid-state lithium-ion batteries can be used. For example, lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium manganese oxide (LiMn2O4), solid solution oxide (Li2MnO3-LiMO2 (M = Co, Ni, etc.)), lithium manganese-nickel-cobalt oxide (LiNi x Mn y Co z O2, x+y+z=1), composite oxides such as olivine-type lithium phosphate (LiFePO4); conductive polymers such as polyaniline and polypyrrole; sulfides such as Li2S, CuS, Li-Cu-S compounds, TiS2, FeS, MoS2, and Li-Mo-S compounds; mixtures of sulfur and carbon; etc. The positive electrode active material may be composed of one kind of the above materials alone, or may be composed of two or more kinds.

[0027] The positive electrode active material layer 20 may contain a conductive additive to improve conductivity. Examples of the conductive additive include carbon blacks such as acetylene black and Ketjen black; carbon fibers; vapor-grown carbon fibers; graphite powder; and carbon materials such as carbon nanotubes. The conductive additive may be composed of one or more of the above materials.

[0028] The positive electrode active material layer 20 may also contain a binder that functions to bind the positive electrode active materials together and between the positive electrode active material and the positive electrode current collector 10 .

[0029] In this embodiment, the positive electrode active material layer 20 is formed on one main surface 10a of the positive electrode current collector 10, but is not limited thereto, and the positive electrode active material layer 20 may be formed on both main surfaces of the positive electrode current collector 10. Furthermore, when the positive electrode active material layer 20 has a three-dimensional porous structure such as a mesh, nonwoven fabric, or foam, the positive electrode active material layer 20 may be provided integrally with the positive electrode current collector 10.

[0030] (solid electrolyte layer) The solid electrolyte layer 30 is disposed between the positive electrode active material layer 20 and the negative electrode current collector 40 .

[0031] The solid electrolyte is not particularly limited as long as it has lithium ion conductivity and insulating properties, and materials generally used in all-solid-state lithium ion batteries can be used. Examples include inorganic solid electrolytes such as sulfide solid electrolyte materials, oxide solid electrolyte materials, halide solid electrolytes, and lithium-containing salts, polymer-based solid electrolytes such as polyethylene oxide, and gel-based solid electrolytes containing lithium-containing salts and lithium ion-conductive ionic liquids. Among these, sulfide solid electrolyte materials are preferred from the viewpoints of high lithium ion conductivity, structural formability by pressing, and interfacial bonding. The form of the solid electrolyte material is not particularly limited, but may be, for example, in the form of particles.

[0032] The solid electrolyte layer 30 may contain an adhesive to impart mechanical strength and flexibility.

[0033] The solid electrolyte layer 30 may be in the form of a sheet having a support and a solid electrolyte supported on the support. The form of the support is not particularly limited, and examples thereof include woven fabric, nonwoven fabric, mesh cloth, porous membrane, expanded sheet, and punched sheet. Among these forms, nonwoven fabric is preferred from the viewpoint of handleability, which allows for a greater loading amount of solid electrolyte.

[0034] The support is preferably made of an insulating material, which can improve the insulating properties of the solid electrolyte layer 30. Examples of insulating materials include resin materials such as nylon, polyester, polyethylene, polypropylene, polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, polyvinylidene fluoride, polyvinylidene chloride, polyvinyl chloride, polyurethane, vinylon, polybenzimidazole, polyimide, polyphenylene sulfite, polyether ether ketone, cellulose, and acrylic resin; natural fibers such as hemp, wood pulp, and cotton linter; and glass.

[0035] (Negative electrode) The negative electrode utilizes a deposition-dissolution reaction of metallic lithium and has a second active material layer containing at least a negative electrode active material.

[0036] The second current collector layer contains at least copper (Cu). Like the first current collector layer, the second current collector layer may contain a material other than copper that has high conductivity. Examples of highly conductive materials other than copper include metals or alloys containing at least one of silver (Ag), palladium (Pd), gold (Au), platinum (Pt), chromium (Cr), and nickel (Ni), or non-metals such as carbon (C). Considering not only high conductivity but also manufacturing costs, nickel or stainless steel is preferred as the material other than copper. Furthermore, stainless steel is less likely to react with the positive electrode active material, negative electrode active material, and electrolyte. Therefore, using stainless steel for the second current collector layer can reduce battery manufacturing costs.

[0037] The second current collector layer may be in the form of, for example, a foil, a plate, a mesh, a nonwoven fabric, a foam, etc. In order to improve adhesion to the second active material layer, carbon or the like may be disposed on the surface of the second current collector layer, or the surface may be roughened.

[0038] The second active material layer contains a negative electrode active material that donates and accepts lithium ions and electrons. The negative electrode active material is not particularly limited as long as it is a material that can reversibly absorb and release lithium ions and transport electrons, and known negative electrode active materials that can be used for the negative electrode of a lithium ion battery can be used. Examples of such materials include carbonaceous materials such as natural graphite, artificial graphite, resin carbon, carbon fiber, activated carbon, hard carbon, and soft carbon; alloy-based materials mainly composed of tin, tin alloys, silicon, silicon alloys, gallium, gallium alloys, indium, indium alloys, aluminum, and aluminum alloys; conductive polymers such as polyacene, polyacetylene, and polypyrrole; metallic lithium; lithium titanium composite oxides (e.g., Li4Ti5O 12 These negative electrode active materials may be composed of one kind of the above materials alone, or two or more kinds of them.

[0039] The second active material layer contains an electrolyte that transfers lithium ions to and from the negative electrode active material. The electrolyte is not particularly limited as long as it has lithium ion conductivity, and materials generally used in lithium ion batteries can be used. Examples of the electrolyte include inorganic solid electrolytes such as sulfide solid electrolyte materials, oxide solid electrolyte materials, halide solid electrolytes, and lithium-containing salts, polymer-based solid electrolytes such as polyethylene oxide, and gel-based solid electrolytes containing lithium-containing salts and lithium-ion conductive ionic liquids. The electrolyte may be composed of one or more of the above materials. The electrolyte contained in the second active material layer may be the same as or different from the electrolyte contained in the first active material layer or the solid electrolyte layer.

[0040] The second active material layer may contain a conductive additive, a binder, etc. These materials are not particularly limited, and may be, for example, the same materials as those used in the first active material layer described above.

[0041] The second active material layer may be formed on both main surfaces of the second current collector layer, or on only one main surface of the second current collector layer. When the second current collector layer has a three-dimensional porous structure such as a mesh, nonwoven fabric, or foam, the second current collector layer may be provided integrally with the second active material layer.

[0042] (insulating material) The insulating material forming the insulating member 50 is not particularly limited, but examples thereof include insulating oxides such as alumina, resins such as polyvinylidene fluoride (PVDF), and rubbers such as styrene-butadiene rubber (SBR).

[0043] According to the electrode laminate 1 of the present embodiment, a positive electrode active material layer 20 is formed on one main surface 10 a of a positive electrode current collector 10, and the positive electrode active material layer 20 has an inclined portion 20 a that is inclined so that its width narrows in a direction away from the one main surface 10 a of the positive electrode current collector 10. The solid electrolyte layer 30 has low ion conductivity regions 31 in which the ionic conductivity of the solid electrolyte is lower than the ionic conductivity of the solid electrolyte in a central portion of the solid electrolyte layer 30, in a region extending from the boundary between the positive electrode active material layer 20 and the insulating member 50 to a distance A in one direction perpendicular to the thickness direction of the solid electrolyte layer 30, and in a region extending from the boundary between the positive electrode active material layer 20 and the insulating member 50 to a distance B in the other direction perpendicular to the thickness direction of the solid electrolyte layer 30. Since the positive electrode active material layer 20 has the inclined portion 20 a that is inclined so that its width narrows in a direction away from the positive electrode current collector 10, current concentration at the boundary between the positive electrode active material layer 20 and the insulating member 50 can be suppressed. As a result, localized deposition of lithium on the negative electrode containing metallic lithium or a lithium alloy can be suppressed.

[0044] The results of simulating the current density of the electrode stack 1 are shown in Fig. 2. In Fig. 2, the top vertical line on the page indicates the total current density (magnitude), the bottom vertical line on the page indicates the current density in the y direction, and the center line indicates the current density in the x direction. 2, current concentration is suppressed in the electrode stack 1. Therefore, in the electrode stack 1, localized deposition of lithium can be suppressed on the negative electrode side containing metallic lithium or a lithium alloy.

[0045] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as set forth in the claims. [Example]

[0046] The present invention will be explained in more detail below by way of experimental examples, but the present invention is not limited to the following experimental examples.

[0047] [Experimental Example 1] Fig. 4 shows the results of a simulation of the current density of the solid electrolyte layer 30 of the electrode stack 1 shown in Fig. 3. Fig. 4 is a diagram showing the relationship between the length of the solid electrolyte layer 30 in the width direction and the current density of the solid electrolyte layer 30. 4, the current density of the solid electrolyte layer 30 was 0.57 S / m in the high ion conduction region 32 (Sigma_high), 0.57 S / m in the low ion conduction region 31 (Sigma_low), and 0.57 S / m in the center (Sigma_SE). Note that w_SE_offset A (one direction perpendicular to the thickness direction of the solid electrolyte layer 30 (in FIG. 3, the direction to the left of the boundary between the positive electrode active material layer 20 and the insulating member 50)) shown in FIG. 4 was 50 μm, and w_SE_offset B (one direction perpendicular to the thickness direction of the solid electrolyte layer 30 (in FIG. 3, the direction to the right of the boundary between the positive electrode active material layer 20 and the insulating member 50)) was 50 μm. In addition,

[0048] [Experimental Example 2] 5 shows the results of simulating the current density of the solid electrolyte layer 30 of the electrode stack 1 shown in Fig. 3. Fig. 5 is a diagram showing the relationship between the length of the solid electrolyte layer 30 in the width direction and the current density of the solid electrolyte layer 30. 5, the current density of the solid electrolyte layer 30 was 1.00 S / m in the high ion conduction region 32 (Sigma_high), 0.57 S / m in the low ion conduction region 31 (Sigma_low), and 0.57 S / m in the center (Sigma_SE). Note that w_SE_offset A shown in FIG. 5 was 50 μm, and w_SE_offset B was 50 μm.

[0049] [Experimental Example 3] 6 shows the results of simulating the current density of the solid electrolyte layer 30 of the electrode stack 1 shown in Fig. 3. Fig. 6 is a diagram showing the relationship between the length of the solid electrolyte layer 30 in the width direction and the current density of the solid electrolyte layer 30. 6, the current density of the solid electrolyte layer 30 was 0.57 S / m in the high ion conduction region 32 (Sigma_high), 0.35 S / m in the low ion conduction region 31 (Sigma_low), and 0.57 S / m in the center (Sigma_SE). Note that w_SE_offset A shown in FIG. 6 was 50 μm, and w_SE_offset B was 50 μm.

[0050] [Experimental Example 4] 7 shows the results of simulating the current density of the solid electrolyte layer 30 of the electrode stack 1 shown in Fig. 3. Fig. 7 is a diagram showing the relationship between the length of the solid electrolyte layer 30 in the width direction and the current density of the solid electrolyte layer 30. 7, the current density of the solid electrolyte layer 30 was 0.57 S / m in the high ion conduction region 32 (Sigma_high), 0.20 S / m in the low ion conduction region 31 (Sigma_low), and 0.57 S / m in the center (Sigma_SE). Note that w_SE_offset A shown in FIG. 7 was 50 μm, and w_SE_offset B was 50 μm.

[0051] [Experimental Example 5] 8 shows the results of simulating the current density of the solid electrolyte layer 30 of the electrode stack 1 shown in Fig. 3. Fig. 8 is a diagram showing the relationship between the length of the solid electrolyte layer 30 in the width direction and the current density of the solid electrolyte layer 30. 8, the current density of the solid electrolyte layer 30 was 0.57 S / m in the high ion conduction region 32 (Sigma_high), 0.10 S / m in the low ion conduction region 31 (Sigma_low), and 0.57 S / m in the center (Sigma_SE). Note that w_SE_offset A shown in FIG. 8 was 50 μm, and w_SE_offset B was 50 μm.

[0052] [Experimental Example 6] 9 shows the results of simulating the current density of the solid electrolyte layer 30 of the electrode stack 1 shown in Fig. 3. Fig. 9 is a diagram showing the relationship between the length of the solid electrolyte layer 30 in the width direction and the current density of the solid electrolyte layer 30. 9, the current density of the solid electrolyte layer 30 was 0.57 S / m in the high ion conduction region 32 (Sigma_high), 0.10 S / m in the low ion conduction region 31 (Sigma_low), and 0.57 S / m in the center (Sigma_SE). Note that w_SE_offset A shown in FIG. 9 was 50 μm, and w_SE_offset B was 50 μm.

[0053] [Experimental Example 7] 10 shows the results of simulating the current density of the solid electrolyte layer 30 of the electrode stack 1 shown in Fig. 3. Fig. 10 is a diagram showing the relationship between the length of the solid electrolyte layer 30 in the width direction and the current density of the solid electrolyte layer 30. 10, the current density of the solid electrolyte layer 30 was 0.57 S / m in the high ion conduction region 32 (Sigma_high), 0.10 S / m in the low ion conduction region 31 (Sigma_low), and 0.57 S / m in the center (Sigma_SE). Note that w_SE_offset A shown in FIG. 10 was 100 μm, and w_SE_offset B was 100 μm.

[0054] [Experimental Example 8] 11 shows the results of simulating the current density of the solid electrolyte layer 30 of the electrode stack 1 shown in Fig. 3. Fig. 11 is a diagram showing the relationship between the length of the solid electrolyte layer 30 in the width direction and the current density of the solid electrolyte layer 30. 11, the current density of the solid electrolyte layer 30 was 0.57 S / m in the high ion conduction region 32 (Sigma_high), 0.10 S / m in the low ion conduction region 31 (Sigma_low), and 0.57 S / m in the center (Sigma_SE). Note that w_SE_offset A shown in FIG. 11 was 300 μm, and w_SE_offset B was 300 μm.

[0055] [Experimental Example 9] 12 shows the results of simulating the current density of the solid electrolyte layer 30 of the electrode stack 1 shown in Fig. 3. Fig. 12 is a diagram showing the relationship between the length of the solid electrolyte layer 30 in the width direction and the current density of the solid electrolyte layer 30. 12, the current density of the solid electrolyte layer 30 was 0.57 S / m in the high ion conduction region 32 (Sigma_high), 0.05 S / m in the low ion conduction region 31 (Sigma_low), and 0.57 S / m in the center (Sigma_SE). Note that w_SE_offset A shown in FIG. 12 was 50 μm, and w_SE_offset B was 50 μm.

[0056] [Experimental Example 10] 13 shows the results of simulating the current density of the solid electrolyte layer 30 of the electrode stack 1 shown in Fig. 3. Fig. 13 is a diagram showing the relationship between the length of the solid electrolyte layer 30 in the width direction and the current density of the solid electrolyte layer 30. 13, the current density of the solid electrolyte layer 30 was 0.57 S / m in the high ion conduction region 32 (Sigma_high), 0.05 S / m in the low ion conduction region 31 (Sigma_low), and 0.57 S / m in the center (Sigma_SE). Note that w_SE_offset A shown in FIG. 13 was 100 μm, and w_SE_offset B was 100 μm.

[0057] [Experimental Example 11] 14 shows the results of simulating the current density of the solid electrolyte layer 30 of the electrode stack 1 shown in Fig. 3. Fig. 14 is a diagram showing the relationship between the length of the solid electrolyte layer 30 in the width direction and the current density of the solid electrolyte layer 30. 14, the current density of the solid electrolyte layer 30 was 0.57 S / m in the high ion conduction region 32 (Sigma_high), 0.05 S / m in the low ion conduction region 31 (Sigma_low), and 0.57 S / m in the center (Sigma_SE). Note that w_SE_offset A shown in FIG. 14 was 300 μm, and w_SE_offset B was 300 μm.

[0058] [Experimental Example 12] 15 shows the results of simulating the current density of the solid electrolyte layer 30 of the electrode stack 1 shown in Fig. 3. Fig. 15 is a diagram showing the relationship between the length of the solid electrolyte layer 30 in the width direction and the current density of the solid electrolyte layer 30. 15, the current density of the solid electrolyte layer 30 was 0.57 S / m in the high ion conduction region 32 (Sigma_high), 0.10 S / m in the low ion conduction region 31 (Sigma_low), and 0.57 S / m in the center (Sigma_SE). Note that w_SE_offset A shown in FIG. 15 was 800 μm, and w_SE_offset B was 300 μm.

[0059] [Experimental Example 13] 16 shows the results of simulating the current density of the solid electrolyte layer 30 of the electrode stack 1 shown in Fig. 3. Fig. 16 is a diagram showing the relationship between the length of the solid electrolyte layer 30 in the width direction and the current density of the solid electrolyte layer 30. 16, the current density of the solid electrolyte layer 30 was 0.57 S / m in the high ion conduction region 32 (Sigma_high), 0.10 S / m in the low ion conduction region 31 (Sigma_low), and 0.57 S / m in the center (Sigma_SE). Note that w_SE_offset A shown in FIG. 15 was 500 μm, and w_SE_offset B was 300 μm.

[0060] [Experimental Example 14] 17 shows the results of simulating the current density of the solid electrolyte layer 30 of the electrode stack 1 shown in Fig. 3. Fig. 17 is a diagram showing the relationship between the length of the solid electrolyte layer 30 in the width direction and the current density of the solid electrolyte layer 30. 17, the current density of the solid electrolyte layer 30 was 0.57 S / m in the high ion conduction region 32 (Sigma_high), 0.10 S / m in the low ion conduction region 31 (Sigma_low), and 0.57 S / m in the center (Sigma_SE). Note that w_SE_offset A shown in FIG. 15 was 300 μm, and w_SE_offset B was 300 μm.

[0061] As shown in Experimental Examples 1 to 11, current concentration is suppressed in the electrode stack 1. Therefore, in the electrode stack 1, localized deposition of lithium can be suppressed on the negative electrode side containing metallic lithium or a lithium alloy. As shown in Experimental Examples 12 to 14, even when w_SE_offset A was set to 300 μm, 500 μm, or 500 μm, there was not much difference in the effect of suppressing current concentration in the electrode stack 1. [Explanation of symbols]

[0062] 1 Electrode laminate 10 Positive electrode current collector 20 Cathode active material layer 30 Solid electrolyte layer 31 Low ionic conductivity region 32 High ionic conductivity region 40 Negative electrode current collector 50 Insulating material 61 First contact part 62 Second contact part

Claims

1. An electrode laminate that utilizes a deposition-dissolution reaction of metallic lithium as a negative electrode reaction, a positive electrode current collector, a positive electrode active material layer, a solid electrolyte layer, and a negative electrode current collector; an insulating member is disposed on the outer periphery of the positive electrode active material layer; the solid electrolyte layer has a low ion-conductivity region in which the ion conductivity of the solid electrolyte is lower than the ion conductivity of the solid electrolyte in a central portion of the solid electrolyte layer, the low ion-conductivity region being a region extending from a boundary line between the positive electrode active material layer and the insulating member to a distance A in one direction perpendicular to the thickness direction of the solid electrolyte layer, and a region extending from a boundary line between the positive electrode active material layer and the insulating member to a distance B in the other direction perpendicular to the thickness direction of the solid electrolyte layer, the positive electrode active material layer has an inclined portion that is inclined so that its width narrows in a direction away from the positive electrode current collector, The electrode stack, wherein the distance A and the distance B satisfy the following relational expression (1): Distance A = Distance B, Distance A ≤ Distance B, Distance A ≥ Distance B (1)

2. 2. The electrode stack according to claim 1, wherein a proportion of the low ion conductive region in a first contact portion where the inclined portion and the solid electrolyte layer are in contact with each other is also high in a distance from a second contact portion where the inclined portion and the positive electrode current collector are in contact with each other to a point on the solid electrolyte layer when a straight line is drawn in the stacking direction.

3. 2. The electrode stack according to claim 1, wherein the distance A is 500 μm or less and the distance B is 500 μm or less.

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