Solid state battery

Abstract

To easily secure an insulation distance between a conductor on a positive electrode side and a conductor on a negative electrode side while a load to a positive electrode side with respect to an edge part of a negative electrode is easily received by a positive electrode frame.SOLUTION: A solid state battery includes a positive electrode current collector, a positive electrode material layer, a predetermined solid electrolyte layer, a negative electrode side solid electrolyte layer, and a negative electrode in order toward at least one side in a stacking direction, and a positive electrode frame of an insulator surrounding the positive electrode material layer from a periphery is provided on a side closer to the negative electrode side than the positive electrode current collector including a positive electrode tab protruding from the positive electrode current collector and a negative electrode tab protruding from the negative electrode. Hereinafter, an area inside an outer edge of the positive electrode frame is defined as "sF", an area of the predetermined solid electrolyte layer is defined as "sEc", an area of the negative electrode side solid electrolyte layer is defined as "sEn", and an area of the negative electrode is defined as "sN". The solid state battery satisfies the relationship of "sEc≥sF>sN≥sEn".SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a solid-state battery to be mounted on a vehicle or the like. [Background technology]

[0002] In recent years, electric vehicles such as EVs and HEVs have become increasingly popular in order to reduce carbon dioxide emissions and thereby mitigate adverse effects on the global environment. Among the secondary batteries installed in electric vehicles and the like, there are the following solid-state batteries.

[0003] The solid-state battery includes a positive electrode current collector, and, in this order from the positive electrode current collector toward both sides in the stacking direction, a positive electrode material layer, a solid electrolyte layer, and a negative electrode. A positive electrode frame made of an insulator is provided on the negative electrode layer side of the positive electrode current collector. The positive electrode current collector and the positive electrode material layer form a positive electrode. The solid-state battery also includes a positive electrode tab protruding from the positive electrode current collector and a negative electrode tab protruding from the negative electrode.

[0004] This solid-state battery is stored in a state where adjacent layers are pressed inward in the stacking direction so that they are in close contact with each other in the stacking direction. As a result, when the solid-state battery is in use, the positive electrode is always pressed toward the negative electrode, and the negative electrode is always pressed toward the positive electrode. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2023-148244 Summary of the Invention [Problem to be solved by the invention]

[0006] The present inventors have noticed that such solid-state batteries have the following problems.

[0007] In many of these solid-state batteries, the volume of the negative electrode increases during charging due to the absorption of lithium, and decreases during discharging due to the release of lithium. This increase or decrease in the volume of the negative electrode can cause a short circuit between the positive electrode conductor and the negative electrode conductor. For this reason, it is preferable to ensure as large an insulation distance as possible between the positive electrode conductor and the negative electrode conductor.

[0008] On the other hand, if the areas of the positive electrode current collector and the positive electrode frame as viewed in the stacking direction are reduced and the edges of the positive electrode current collector and the positive electrode frame are recessed inward relative to the edges of the solid electrolyte, thereby ensuring an insulating distance between the conductor on the positive electrode side and the conductor on the negative electrode side, the following problem may occur.

[0009] In other words, when the solid-state battery is in use, the load on the positive electrode side relative to the edge of the negative electrode cannot be supported by the positive electrode frame. As a result, the load tends to be dissipated to the edge of the negative electrode. This can cause problems such as a large amount of lithium being easily absorbed by the edge of the negative electrode during charging.

[0010] The present invention has been made in consideration of the above circumstances, and aims to make it easier to ensure a large insulation distance between the conductor on the positive electrode side and the conductor on the negative electrode side, while making it easier for the positive electrode frame to support the load on the positive electrode side against the edge of the negative electrode. [Means for solving the problem]

[0011] The present inventors have discovered that the above object can be achieved by setting the areas of the layers constituting the solid-state battery in a predetermined relationship, and have arrived at the present invention. The present invention relates to the following solid-state batteries (1) to (12).

[0012] (1) A battery comprising, in order in at least one stacking direction, a positive electrode current collector, a positive electrode material layer, a predetermined solid electrolyte layer, a negative electrode-side solid electrolyte layer, and a negative electrode, and also comprising a positive electrode tab protruding from the positive electrode current collector and a negative electrode tab protruding from the negative electrode, a positive electrode frame made of an insulator that surrounds the positive electrode material layer is provided on the negative electrode side of the positive electrode current collector, A solid-state battery in which the volume of the negative electrode increases upon charging and decreases upon discharging, The area inside the outer edge of the positive electrode frame in a plan view in the stacking direction is defined as "sF", the area of ​​the predetermined solid electrolyte layer in the plan view is defined as "sEc", the area of ​​the negative electrode-side solid electrolyte layer in the plan view is defined as "sEn", and the area of ​​the negative electrode in the plan view is defined as "sN", The relationship "sEc ≥ sF > sN ≥ sEn" is satisfied. solid state battery.

[0013] According to this configuration, since "sN≧sEn" holds, it becomes easy to transfer the negative electrode solid electrolyte layer side to the negative electrode side using the negative electrode side as a base.

[0014] In addition, since "sF > sEn" holds, the surface of the negative electrode solid electrolyte layer on the positive electrode frame side tends to be flat. Furthermore, since "sF > sN" holds, the positive electrode frame tends to expand to the portion corresponding to the edge of the negative electrode. These factors make it easier for the positive electrode frame to withstand the load on the positive electrode side from the edge of the negative electrode.

[0015] Furthermore, since sEc≧sF, the edge of the predetermined solid electrolyte layer is likely to protrude outward beyond the edge of the positive electrode frame, which makes it easier to ensure an insulating distance between the positive electrode conductor and the negative electrode conductor by the predetermined solid electrolyte layer.

[0016] As described above, this configuration makes it easier for the positive electrode frame to support the load on the positive electrode side applied to the edge of the negative electrode, while also making it easier to ensure an insulation distance between the conductor on the positive electrode side and the conductor on the negative electrode side.

[0017] (2) An intermediate layer is provided between the negative electrode-side solid electrolyte layer and the negative electrode, The area of ​​the intermediate layer is defined as "sM", The relationship "sN ≥ sM ≥ sEn" is satisfied. The solid-state battery according to (1) above.

[0018] According to this configuration, the performance of the solid-state battery can be further improved by assigning a predetermined role to the intermediate layer. Furthermore, since "sN ≧ sM" holds, it is easy to transfer the intermediate layer to the negative electrode using the negative electrode side as a base. Furthermore, even when the intermediate layer constitutes the negative electrode side conductor, since "sN ≧ sM" holds, it is easy to ensure an insulating distance between the intermediate layer and the positive electrode side conductor. Furthermore, since "sM ≧ sEn" holds, it is easy to transfer the negative electrode side solid electrolyte layer to the intermediate layer using the intermediate layer side as a base.

[0019] (3) A cathode-side solid electrolyte layer is provided between the cathode material layer and the predetermined solid electrolyte layer, The area of ​​the positive electrode side solid electrolyte layer in the plan view is defined as "sEp", The relationship "sEc ≥ sF ≥ sEp" is satisfied. The solid state battery according to (1) or (2).

[0020] According to this configuration, since "sF≧sEp", it is easy to transfer the positive electrode side solid electrolyte layer to the positive electrode frame using the positive electrode frame as a base. Also, since "sEc≧sEp", it is easy to transfer the positive electrode side solid electrolyte layer to the predetermined solid electrolyte layer.

[0021] (4) The relationship "sEc>sF" is satisfied. The solid state battery according to any one of (1) to (3) above.

[0022] According to this configuration, the predetermined solid electrolyte layer protrudes outward from the positive electrode frame, thereby further improving the insulation between the positive electrode side conductor and the negative electrode side conductor.

[0023] (5) The predetermined solid electrolyte layer protrudes beyond the positive electrode frame in the protruding direction of the negative electrode tab. The solid state battery according to any one of (1) to (4) above.

[0024] According to this configuration, the predetermined solid electrolyte layer ensures an insulating distance between the negative electrode tab and the positive electrode current collector.

[0025] (6) The predetermined solid electrolyte layer is thicker in the stacking direction than the negative electrode side solid electrolyte layer. The solid state battery according to any one of (1) to (5) above.

[0026] According to this configuration, by making the predetermined solid electrolyte layer, which has the largest area and is most likely to protrude outward, thicker in the stacking direction, the predetermined solid electrolyte layer can be made less susceptible to damage even by a press load or the like.

[0027] (7) The predetermined solid electrolyte layer includes a porous substrate and a solid electrolyte filled in the substrate. The solid state battery according to any one of (1) to (6) above.

[0028] According to this configuration, by including a base material in the predetermined solid electrolyte layer, the predetermined solid electrolyte layer can be made less susceptible to damage even when subjected to a press load or the like.

[0029] (8) The predetermined solid electrolyte layer contains a binder, the binder content of the predetermined solid electrolyte layer is different from the binder content of the negative electrode-side solid electrolyte layer; The solid state battery according to any one of (1) to (7) above.

[0030] According to this configuration, by making the binder content of the predetermined solid electrolyte layer different from the binder content of the negative electrode solid electrolyte layer, it is easy to adjust the strength of the predetermined solid electrolyte layer to be high, and this makes it possible to make the predetermined solid electrolyte layer less susceptible to damage even by a press load or the like.

[0031] (9) A positive electrode tab insulating portion is provided that protrudes from the positive electrode frame in the protruding direction of the positive electrode tab, the positive electrode tab insulating portion protrudes further in the protruding direction of the positive electrode tab than the solid electrolyte layer; The solid state battery according to any one of (1) to (8) above.

[0032] According to this configuration, the positive electrode tab insulating portion can ensure a larger insulation distance between the positive electrode tab and the negative electrode.

[0033] (10) A cathode-side solid electrolyte layer is provided between the cathode material layer and the predetermined solid electrolyte layer, An intermediate layer is provided between the negative electrode-side solid electrolyte layer and the negative electrode. The area of ​​the positive electrode material layer in the plan view is defined as "sPm", The area of ​​the positive electrode-side solid electrolyte layer in the plan view is defined as "sEp", The area of ​​the intermediate layer in the plan view is defined as "sM", The relationship "sEc ≥ sF ≥ sEp ≥ sN ≥ sM ≥ sEn ≥ sPm" is satisfied. The solid state battery according to any one of (1) to (9) above.

[0034] According to this configuration, since "sF ≧ sEp", it is easy to transfer the positive electrode-side solid electrolyte layer to the positive electrode frame and the positive electrode material layer using the positive electrode frame side as a base. Furthermore, since "sN ≧ sM ≧", it is easy to transfer the intermediate layer to the negative electrode using the negative electrode side as a base. Furthermore, since "sM ≧ sEn", it is easy to transfer the negative electrode-side solid electrolyte layer to the intermediate layer using the intermediate layer side as a base. Furthermore, since "sEc > sEp", it is easy to transfer the positive electrode-side solid electrolyte layer to a predetermined solid electrolyte layer. Furthermore, since "sEc > sEn", it is easy to transfer the negative electrode-side solid electrolyte layer to a predetermined solid electrolyte layer.

[0035] (11) A resin coating is provided to cover an end portion of a stack including the positive electrode current collector, the positive electrode material layer, the positive electrode frame, the predetermined solid electrolyte layer, the negative electrode-side solid electrolyte layer, and the negative electrode, on a side perpendicular to the stacking direction. The solid state battery according to any one of (1) to (10) above.

[0036] According to this configuration, the resin coating can further improve the insulation between the positive electrode conductor and the negative electrode conductor. Furthermore, since "sEc>sEn" in (1) cited in this configuration, the resin coating can easily penetrate into the region between the predetermined solid electrolyte layer and the negative electrode tab, including the area outside the edge of the negative electrode solid electrolyte layer.

[0037] (12) The negative electrode includes a negative electrode current collector and a negative electrode material layer that is disposed closer to the positive electrode current collector than the negative electrode current collector and contains metallic lithium. The solid state battery according to any one of (1) to (11) above.

[0038] According to this configuration, the above-mentioned effects can be obtained in such a solid-state battery. [Effects of the Invention]

[0039] As described above, the configuration (1) makes it easy to receive the load on the edge of the negative electrode toward the positive electrode side by the positive electrode frame, while making it easy to ensure a large insulation distance between the conductor on the positive electrode side and the conductor on the negative electrode side. Furthermore, the configurations (2) to (12) that refer to the configuration (1) above provide additional effects. [Brief explanation of the drawings]

[0040] [Figure 1] FIG. 2 is an exploded perspective view showing each layer of the solid state battery of the first embodiment. [Figure 2] FIG. 2 is a plan view showing a solid-state battery. [Figure 3] FIG. 3 is a cross-sectional view showing a cross section taken along line fg3-fg3 in FIG. 2. [Figure 4] FIG. 3 is a cross-sectional view showing a cross section of line fg4-fg4 in FIG. 2. [Figure 5] FIG. 10 is a cross-sectional view of the solid state battery of the second embodiment as viewed in the X direction. [Figure 6] FIG. 2 is a cross-sectional view of the solid-state battery as viewed in the Y direction. DETAILED DESCRIPTION OF THE INVENTION

[0041] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments and can be appropriately modified and implemented within the scope of the present invention.

[0042] [First embodiment] The solid-state battery Bt of this embodiment shown in FIG. 1 is a lithium metal secondary battery and includes multiple layers. Hereinafter, the three mutually orthogonal directions will be referred to as the "X direction," "Y direction," and "Z direction." Note that the "Z direction" may also be interpreted as the stacking direction. Hereinafter, one side of the X direction will be referred to as the "X-side," and the opposite side will be referred to as the "X+ side." One side of the Y direction will be referred to as the "Y-side," and the other side of the Y direction will be referred to as the "Y+ side." One side of the Z direction will be referred to as the "Z-side," and the opposite side will be referred to as the "Z+ side."

[0043] 3, the solid-state battery Bt includes a positive electrode current collector Pc, and, in order from the positive electrode current collector Pc toward the Z+ side and the Z- side, a positive electrode material layer Pm, a positive electrode-side electrolyte layer Ep, an intermediate electrolyte layer Ec, a negative electrode-side electrolyte layer En, an intermediate layer M, a negative electrode material layer Nm, and a negative electrode current collector Nc. The solid-state battery Bt also includes an insulating positive electrode frame F that surrounds the positive electrode material layer Pm on each of the Z+ side and the Z- side of the positive electrode current collector Pc.

[0044] The positive electrode current collector Pc and the positive electrode material layer Pm constitute the positive electrode P. The positive electrode-side electrolyte layer Ep, the intermediate electrolyte layer Ec, and the negative electrode-side electrolyte layer En constitute the solid electrolyte layer E. Note that the terms "positive electrode-side electrolyte layer Ep," "intermediate electrolyte layer Ec," and "negative electrode-side electrolyte layer En" may be read as "positive electrode-side solid electrolyte layer," "predetermined solid electrolyte layer," and "negative electrode-side solid electrolyte layer," respectively. The negative electrode material layer Nm and the negative electrode current collector Nc constitute the negative electrode N.

[0045] Hereinafter, the plan view in the Z direction will be simply referred to as the "plan view." In addition, in the following, the area inside the outer edge of the positive electrode frame F in a plan view will be defined as "sF." In addition, the area of ​​the positive electrode material layer Pm in a plan view will be defined as "sPm." In addition, the area of ​​the positive electrode side electrolyte layer Ep in a plan view will be defined as "sEp." In addition, the area of ​​the intermediate electrolyte layer Ec in a plan view will be defined as "sEc." In addition, the area of ​​the negative electrode side solid electrolyte layer E in a plan view will be defined as "sEn." In addition, the area of ​​the intermediate layer M in a plan view will be defined as "sM." In addition, the area of ​​the negative electrode N in a plan view will be defined as "sN." Therefore, "sN" is the area of ​​the portion including the negative electrode material layer Nm and the negative electrode current collector layer Nc in a plan view. In this embodiment, since the area of ​​the negative electrode current collector layer Nc is equal to or larger than the area of ​​the negative electrode material layer Nm in plan view, "sN" is essentially the area of ​​the negative electrode current collector layer Nc in plan view.

[0046] The solid-state battery Bt further includes a positive electrode tab Tp protruding from the positive electrode current collector Pc toward the Y+ side. Therefore, the "Y+ side" may be interpreted as the "protruding direction of the positive electrode tab Tp." The positive electrode P and the positive electrode tab Tp constitute a conductor on the positive electrode P side. The solid-state battery Bt further includes a positive electrode tab insulating portion Ip protruding from the positive electrode frame F toward the Y+ side. The area of ​​the positive electrode tab insulating portion Ip is not included in "sF." The solid-state battery Bt further includes a negative electrode tab Tn protruding from the negative electrode current collector Nc toward the Y- side. Therefore, the "Y- side" may be interpreted as the "protruding direction of the negative electrode tab Tn." The area of ​​the negative electrode tab Tn is not included in "sN." The intermediate layer M, the negative electrode N, and the negative electrode tab Tn constitute a conductor on the negative electrode N side.

[0047] Next, the details of each layer of the solid state battery Bt will be described in order starting from the positive electrode P side.

[0048] A specific example of the material that constitutes the positive electrode current collector Pc is aluminum foil, etc. The positive electrode tab Tp is formed integrally with the positive electrode current collector Pc.

[0049] The positive electrode layer Pm contains a positive electrode active material capable of absorbing and releasing lithium. Specific examples of the positive electrode active material include LiCoO2, Li(Ni5 / 10Co2 / 10Mn3 / 10)O2, Li(Ni6 / 10Co2 / 10Mn2 / 10)O2, Li(Ni8 / 10Co1 / 10Mn1 / 10)O2, Li(Ni0.8Co0.15Al0.05)O2, Li(Ni1 / 6Co4 / 6Mn1 / 6)O2, Li(Ni1 / 3Co1 / 3Mn1 / 3)O2, LiCoO4, LiMn2O4, LiNiO2, LiFePO4, lithium sulfide, and sulfur. The positive electrode layer Pm may further contain a solid electrolyte, a conductive additive, a binder, and the like. The positive electrode layer Pm is located inside the positive electrode frame F. Therefore, among "sPm," "sF," "sEp," "sEc," "sEn," "sM," and "sN," "sPm" is the smallest.

[0050] As shown in Figure 1, the positive electrode frame F has a rectangular frame shape in plan view. Specific examples of materials that make up the positive electrode frame F include insulating oxides such as alumina, resins such as polyvinylidene fluoride (PVDF), and rubbers such as styrene-butadiene rubber (SBR). The positive electrode tab insulating part Ip is integrally formed with the positive electrode frame F.

[0051] The solid electrolyte layer E shown in Fig. 3 contains a solid electrolyte capable of conducting lithium ions. Specific examples of the solid electrolyte include oxide-based electrolytes and sulfide-based electrolytes. The solid electrolyte layer E also contains a binder.

[0052] The positive electrode side electrolyte layer Ep is transferred onto the positive electrode material layer Pm and the positive electrode frame F using the positive electrode P side as a base. This satisfies the relationship "sF≧sEp." The positive electrode side electrolyte layer Ep is then transferred onto the intermediate electrolyte layer Ec. This also satisfies the relationship "sEc≧sEp."

[0053] The intermediate electrolyte layer Ec is a main layer of the solid electrolyte layer E and is thicker in the Z direction than either the positive electrode-side electrolyte layer Ep or the negative electrode-side electrolyte layer En. The intermediate electrolyte layer Ec includes a porous substrate such as a nonwoven fabric and the aforementioned solid electrolyte filled in the substrate. The binder content of the intermediate electrolyte layer Ec is different from the binder content of the negative electrode-side solid electrolyte layer E. In this embodiment, the intermediate electrolyte layer Ec satisfies the relationship "sEc > sF" to ensure an insulation distance between the conductor on the positive electrode P side and the conductor on the negative electrode N side.

[0054] The negative electrode side electrolyte layer En is transferred onto the intermediate layer M using the intermediate layer M side as a base. This satisfies the relationship "sM ≥ sEn." The negative electrode side electrolyte layer En is then transferred onto the intermediate electrolyte layer Ec. This also satisfies the relationship "sEc ≥ sEn."

[0055] Specific examples of materials constituting the intermediate layer M include carbon carrying a metal (e.g., silver) that can be alloyed with lithium. The intermediate layer M stabilizes the interface between the solid electrolyte layer E and the intermediate layer M, as well as the interface between the intermediate layer M and the negative electrode material layer Nm. Furthermore, the intermediate layer M has the function of uniformly depositing lithium metal. The intermediate layer M is transferred to the negative electrode material layer Nm based on the negative electrode N side. This satisfies the relationship "sN ≥ sM." Furthermore, since "sN ≥ sM" holds, it is easy to ensure an insulating distance between the intermediate layer M and the conductor on the positive electrode P side.

[0056] The negative electrode layer Nm includes a negative electrode active material capable of absorbing and releasing lithium ions. Specific examples of the negative electrode active material include metallic lithium, lithium alloys, metal oxides, metal sulfides, metal nitrides, Si, SiO, and carbon materials. Examples of the carbon materials include artificial graphite, natural graphite, hard carbon, and soft carbon. The negative electrode layer Nm may further include a solid electrolyte, a conductive additive, a binder, and the like. Therefore, the negative electrode layer Nm may be, for example, a layer mainly containing metallic lithium, or a layer mainly containing silicon.

[0057] A specific example of the material constituting the negative electrode current collector Nc is copper foil. The negative electrode tab Tn is integrally formed with the negative electrode current collector Nc. From the viewpoint of insulation between the negative electrode current collector Nc and the positive electrode tab Tp, the negative electrode current collector Nc is formed within a range that satisfies the relationship "sF>sN."

[0058] From the above, in this embodiment, the relationship "sEc>sF≧sEp≧sN≧sM≧sEn≧sPm" is satisfied. Also, in this embodiment, the relationship "sF>sN" is satisfied.

[0059] Next, with reference to the left side of FIG. 3 , the positional relationship between the Y+ side ends of each layer of the solid-state battery Bt will be described. The negative electrode side electrolyte layer En, intermediate layer M, negative electrode material layer Nm, and negative electrode current collector Nc each protrude toward the Y+ side beyond the positive electrode material layer Pm. The positive electrode current collector Pc, positive electrode frame F, positive electrode side electrolyte layer Ep, and intermediate electrolyte layer Ec each protrude toward the Y+ side beyond each of these layers En, M, Nm, and Nc. The positive electrode tab insulating portion Ip protrudes in the Y+ direction beyond each of these layers Pc, F, Ep, and Ec. The positive electrode tab Tp protrudes in the Y+ direction beyond the positive electrode tab insulating portion Ip. The protrusion length of the positive electrode tab insulating portion Ip toward the Y+ side from the intermediate electrolyte layer Ec is approximately 0.3 to 1.0 mm.

[0060] Next, with reference to the right side of FIG. 3 , the positional relationship between the Y-side ends of each layer of the solid-state battery Bt will be described. The negative electrode side electrolyte layer En, intermediate layer M, negative electrode material layer Nm, and negative electrode current collector Nc each protrude toward the Y-side beyond the positive electrode material layer Pm. The positive electrode current collector Pc, positive electrode frame F, and positive electrode side electrolyte layer Ep each protrude toward the Y-side beyond each of these layers En, M, Nm, and Nc. The intermediate electrolyte layer Ec protrudes toward the Z-side beyond each of these layers Pc, F, and Ep. The protrusion length of the intermediate electrolyte layer Ec toward the Y-side from the positive electrode frame F is approximately 0.3 to 2.0 mm.

[0061] Next, the positional relationship between the ends in the X direction of each layer of the solid-state battery Bt will be described with reference to Fig. 4. Note that Fig. 4 shows only the end on the X+ side of each layer of the solid-state battery Bt, and does not show the end on the X- side, but the end on the X- side is the same as the end on the X+ side shown in Fig. 4, but flipped around the Z direction as an axis.

[0062] The intermediate layer M, the negative electrode side electrolyte layer En, the negative electrode current collector Nc, and the negative electrode material layer Nm each protrude outward in the X direction from the positive electrode material layer Pm. The positive electrode current collector Pc, the positive electrode frame F, the positive electrode side electrolyte layer Ep, and the intermediate electrolyte layer Ec each protrude outward in the X direction from each of these layers M, En, Nc, and Nm.

[0063] Next, a method for manufacturing the above-described solid-state battery Bt will be described. The manufacturing method includes a positive electrode side manufacturing process, a negative electrode side manufacturing process, and an overall manufacturing process. The positive electrode side manufacturing process and the negative electrode side manufacturing process may be performed in either order, or may be performed in parallel. On the other hand, the overall manufacturing process is performed after the positive electrode side manufacturing process and the negative electrode side manufacturing process. Note that the "transfer" referred to below is performed by a roll press or the like.

[0064] In the positive electrode manufacturing process, a material including a positive electrode side electrolyte layer Ep is transferred onto both surfaces in the Z direction of a material including a positive electrode current collector Pc, a positive electrode tab Tp, a positive electrode material layer Pm, and a positive electrode frame F.

[0065] In the negative electrode manufacturing process, first, a material including an intermediate layer M is transferred onto a material including a negative electrode current collector Nc, a negative electrode tab Tn, and a negative electrode material layer Nm. Next, a material including a negative electrode-side electrolyte layer En is transferred onto the material including the negative electrode current collector Nc, a negative electrode tab Tn, a negative electrode material layer Nm, and an intermediate layer M.

[0066] In the overall manufacturing process, first, a material containing the intermediate electrolyte layer Ec is transferred to both sides of the material manufactured in the positive electrode manufacturing process in the Z direction. Next, the material manufactured in the negative electrode manufacturing process is further transferred to both sides of the transferred material in the Z direction. Next, the material to which these materials have been transferred is cut, thereby completing the internal structure of the solid-state battery Bt.

[0067] The internal structure of the solid-state battery Bt manufactured as described above is stored in a state pressed inward in the Z direction so that adjacent layers in the Z direction are in close contact with each other. Therefore, when the solid-state battery Bt is in use, the positive electrode P is always pressed toward the negative electrode N, and the negative electrode N is always pressed toward the positive electrode P.

[0068] During use, the solid-state battery Bt is repeatedly charged and discharged between a predetermined fully charged state and a predetermined fully discharged state. As the solid-state battery Bt is charged, lithium is absorbed into the negative electrode material layer Nm, increasing the volume of the negative electrode N. On the other hand, as the solid-state battery Bt is discharged, lithium is released from the negative electrode material layer Nm, decreasing the volume of the negative electrode N.

[0069] Hereinafter, the value obtained by dividing the volume of the negative electrode N in the fully charged state of the solid-state battery Bt by the volume of the negative electrode N in the fully discharged state is defined as the "negative electrode expansion rate." In this embodiment, the negative electrode expansion rate is approximately 2.5 times or more and 4.0 times or less. However, the negative electrode expansion rate may be changed as appropriate, for example, within a range of 1.8 times or more and 5.5 times or less.

[0070] The configuration and effects of this embodiment are summarized below.

[0071] The relationship "sEc>sF≧sEp≧sN≧sM≧sEn≧sPm" is satisfied. Since "sF≧sEp", it is easy to transfer the positive electrode side electrolyte layer Ep to the positive electrode frame F and the positive electrode material layer Pm using the positive electrode frame F side as a base. Also, since "sN≧sM≧", it is easy to transfer the intermediate layer M to the negative electrode N using the negative electrode N side as a base. Also, since "sM≧sEn", it is easy to transfer the negative electrode side electrolyte layer En to the intermediate layer M using the intermediate layer M side as a base. Also, since "sEc>sEp", it is easy to transfer the positive electrode side electrolyte layer Ep to the intermediate electrolyte layer Ec. Also, since "sEc>sEn", it is easy to transfer the negative electrode side electrolyte layer En to the intermediate electrolyte layer Ec.

[0072] Since "sF>sEn", the surface of the negative electrode side electrolyte layer En on the positive electrode frame F side is likely to be flat. Furthermore, since "sF>sN", the positive electrode frame F is likely to expand to the portion corresponding to the edge of the negative electrode N. As a result, the load on the positive electrode P side relative to the edge of the negative electrode N is more likely to be received by the positive electrode frame F. As a result, the load is less likely to be dissipated to the edge of the negative electrode N, which is a problem. As a result, the load is less likely to be absorbed to the edge of the negative electrode N, which is a problem.

[0073] Moreover, since "sEc>sF", the edge of the intermediate electrolyte layer Ec protrudes outward beyond the edge of the positive electrode frame F. This makes it easier to ensure an insulating distance between the conductor on the positive electrode P side and the conductor on the negative electrode N side by the intermediate electrolyte layer Ec.

[0074] The intermediate electrolyte layer Ec protrudes in the Y-direction from the positive electrode frame F. The intermediate electrolyte layer Ec ensures an insulating distance between the negative electrode tab Tn and the positive electrode current collector Pc.

[0075] The intermediate electrolyte layer Ec is thicker in the Z-stacking direction than either the positive electrode-side solid electrolyte layer E or the negative electrode-side solid electrolyte layer E. By thickening the intermediate electrolyte layer Ec, which has the largest area and protrudes the most outward, in the Z direction, the intermediate electrolyte layer Ec can be made less susceptible to damage even by a press load.

[0076] The intermediate electrolyte layer Ec includes a porous substrate and a solid electrolyte filled in the substrate. By including the substrate in the intermediate electrolyte layer Ec, the intermediate electrolyte layer Ec can be made less susceptible to damage even when subjected to a press load or the like.

[0077] The binder content of the intermediate electrolyte layer Ec is different from the binder content of the negative electrode side electrolyte layer En. This makes it easier to adjust the strength of the intermediate electrolyte layer Ec to be high. This makes it possible to make the intermediate electrolyte layer Ec less susceptible to damage even when subjected to a press load.

[0078] The positive electrode tab insulating portion Ip protrudes further toward the Y+ side than the intermediate electrolyte layer Ec. The positive electrode frame F ensures a larger insulation distance between the positive electrode tab Tp and the negative electrode N.

[0079] [Second embodiment] Next, a second embodiment will be described with reference to Figures 5 and 6. This embodiment will be described based on the first embodiment, focusing on differences from the first embodiment, and descriptions of the same or similar aspects to the first embodiment will be omitted as appropriate.

[0080] Hereinafter, a main part of the solid-state battery Bt will be referred to as a "laminated body L" as shown in Fig. 5. Specifically, the laminated body L includes a positive electrode P and a positive electrode frame F, as well as a solid electrolyte layer E, an intermediate layer M, and a negative electrode N provided on both sides of the positive electrode P and a positive electrode frame F in the Z direction.

[0081] The solid-state battery Bt further includes a resin coat RC that covers the X-direction and Y-direction end portions of the laminate L. Specifically, the resin coat RC covers the Y+-side end portion of the laminate from the Y+ side, and also covers the Y-side end portion of the laminate from the Y- side. Also, as shown in FIG. 6, the resin coat RC covers the X+-side end portion of the laminate from the X+ side, and also covers the X--side end portion of the laminate L from the X- side.

[0082] According to this embodiment, the resin coating RC can further improve the insulation between the conductor on the positive electrode P side and the conductor on the negative electrode N side. Furthermore, as in the first embodiment, since "sEc>sEn" as shown in Fig. 5, the resin coating RC can easily penetrate into the region including the outer side of the edge of the negative electrode-side solid electrolyte layer En between the intermediate electrolyte layer Ec and the negative electrode tab Tn.

[0083] [Other embodiments] The above-described embodiments can be modified, for example, as follows. In the first embodiment, the positive electrode tab Tp and the negative electrode tab Tn protrude in opposite directions. Alternatively, the positive electrode tab Tp and the negative electrode tab Tn may protrude in the same direction. In cases where the intermediate electrolyte layer Ec can be transferred to the positive electrode P even without the positive electrode-side electrolyte layer Ep, the positive electrode-side electrolyte layer Ep may be omitted.

[0084] The negative electrode N may be anode-free, i.e., have no negative electrode material layer Nm immediately after production. In this case, a lithium metal layer is formed as the negative electrode material layer Nm after the first charge. The solid-state battery Bt may also be a battery other than a lithium metal secondary battery. In this case, the intermediate layer M for uniformly depositing lithium metal may be omitted.

[0085] Even if "sEc=sF" is true, if sufficient insulation between the positive electrode P and the negative electrode N can be ensured, "sEc=sF" may be true. [Explanation of symbols]

[0086] Bt solid state battery Ec intermediate electrolyte layer (predetermined solid electrolyte layer) En Negative electrode side electrolyte layer (negative electrode side solid electrolyte layer) Ep Positive electrode side electrolyte layer (positive electrode side solid electrolyte layer) F Positive electrode frame Ip positive electrode tab insulation M middle layer N negative electrode Nc negative electrode current collector Nm negative electrode material layer P positive electrode PC positive electrode current collector Pm cathode material layer Tn negative electrode tab Tp positive electrode tab RC resin coating

Claims

1. the battery includes, in order in at least one direction of lamination, a positive electrode current collector, a positive electrode material layer, a predetermined solid electrolyte layer, an anode-side solid electrolyte layer, and a negative electrode, and also includes a positive electrode tab protruding from the positive electrode current collector and a negative electrode tab protruding from the negative electrode, a positive electrode frame made of an insulator that surrounds the positive electrode material layer is provided on the negative electrode side of the positive electrode current collector, A solid-state battery in which the volume of the negative electrode increases upon charging and decreases upon discharging, The area inside the outer edge of the positive electrode frame in a plan view in the stacking direction is defined as "sF", the area of ​​the predetermined solid electrolyte layer in the plan view is defined as "sEc", the area of ​​the negative electrode-side solid electrolyte layer in the plan view is defined as "sEn", and the area of ​​the negative electrode in the plan view is defined as "sN", The relationship "sEc ≥ sF > sN ≥ sEn" is satisfied. solid state battery.

2. an intermediate layer is provided between the anode-side solid electrolyte layer and the anode; The area of ​​the intermediate layer is defined as "sM", The relationship "sN ≥ sM ≥ sEn" is satisfied. The solid-state battery according to claim 1 .

3. a cathode-side solid electrolyte layer is provided between the cathode material layer and the predetermined solid electrolyte layer, The area of ​​the positive electrode-side solid electrolyte layer in the plan view is defined as “sEp”, The relationship "sEc ≥ sF ≥ sEp" is satisfied. The solid-state battery according to claim 1 or 2.

4. Satisfy the relationship "sEc>sF" The solid-state battery according to claim 1 or 2.

5. the predetermined solid electrolyte layer protrudes beyond the positive electrode frame in the protruding direction of the negative electrode tab; The solid-state battery according to claim 1 or 2.

6. the predetermined solid electrolyte layer is thicker in the stacking direction than the negative electrode side solid electrolyte layer; The solid-state battery according to claim 1 or 2.

7. The predetermined solid electrolyte layer includes a porous substrate and a solid electrolyte filled in the substrate. The solid-state battery according to claim 1 or 2.

8. the predetermined solid electrolyte layer contains a binder, the binder content of the predetermined solid electrolyte layer is different from the binder content of the negative electrode-side solid electrolyte layer; The solid-state battery according to claim 1 or 2.

9. a positive electrode tab insulating portion protruding from the positive electrode frame in a protruding direction of the positive electrode tab, the positive electrode tab insulating portion protrudes further than the predetermined solid electrolyte layer in the protruding direction of the positive electrode tab; The solid-state battery according to claim 1 or 2.

10. a cathode-side solid electrolyte layer is provided between the cathode material layer and the predetermined solid electrolyte layer, An intermediate layer is provided between the negative electrode-side solid electrolyte layer and the negative electrode. The area of ​​the positive electrode material layer in the plan view is defined as "sPm", The area of ​​the positive electrode-side solid electrolyte layer in the plan view is defined as “sEp”, The area of ​​the intermediate layer in the plan view is defined as “sM”, The relationship "sEc ≥ sF ≥ sEp ≥ sN ≥ sM ≥ sEn ≥ sPm" is satisfied. The solid-state battery according to claim 1 or 2.

11. a resin coating covering an end portion of a stack including the positive electrode current collector, the positive electrode material layer, the positive electrode frame, the predetermined solid electrolyte layer, the negative electrode-side solid electrolyte layer, and the negative electrode in a direction perpendicular to the stacking direction; The solid-state battery according to claim 1 or 2.

12. the negative electrode comprises a negative electrode current collector and a negative electrode material layer that is provided closer to the positive electrode current collector than the negative electrode current collector and that contains metallic lithium; The solid-state battery according to claim 1 or 2.

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