Solid-state battery

Abstract

The problem to be solved by the present invention is to easily block a load on the positive electrode side with respect to the edge of the negative electrode by a positive electrode frame and to easily ensure a large insulation distance between a positive electrode-side conductor and a negative electrode-side conductor. In order to solve the problem, provided is a solid-state battery which is provided with a positive electrode current collector, a positive electrode material layer, a prescribed solid electrolyte layer, a negative electrode-side solid electrolyte layer, and a negative electrode in this order in at least one of the lamination directions, and which is also provided with 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 of an insulator surrounding the positive electrode material layer from the periphery is provided closer to the negative electrode side than the positive electrode current collector. Hereinafter, the area inside the outer edge of the positive electrode frame is defined as "sF", the area of the predetermined solid electrolyte layer is defined as "sEc", the area of the negative electrode-side solid electrolyte layer is defined as "sEn", and the area of the negative electrode is defined as "sN". The solid-state battery satisfies the relationship of "sEc > = sF > sN > = sEn".

Description

Technical Field

[0001] The present invention relates to a solid battery mounted on a vehicle or the like. Background Art

[0002] In recent years, electric vehicles, such as pure electric vehicles (EVs) and hybrid electric vehicles (HEVs), have become increasingly popular to reduce carbon dioxide emissions and mitigate adverse environmental impacts. Among the secondary batteries used in EVs and other vehicles, the following solid-state batteries are common.

[0003] The solid-state battery comprises a positive electrode current collector and, in order from the positive electrode current collector to either side of the stacking direction, a positive electrode material layer, a solid electrolyte layer, and a negative electrode. A positive electrode frame, comprising an insulator surrounding the positive electrode material layer, is provided closer to the negative electrode layer than the positive electrode current collector. The positive electrode current collector and the positive electrode material layer constitute the positive electrode. Furthermore, the solid-state battery comprises a positive electrode tab protruding from the positive electrode current collector and a negative electrode tab protruding from the negative electrode.

[0004] The solid battery is stored in a state where it is pressed inward in the stacking direction so that adjacent layers in the stacking direction are in close contact with each other. As a result, when the solid battery is in use, the positive electrode is always pressed against the negative electrode, and the negative electrode is always pressed against the positive electrode.

[0005] [Prior Art Literature]

[0006] (Patent Document)

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2023-148244 Summary of the Invention

[0008] [Problems to be solved by the invention]

[0009] The present inventors have focused on the following problems in such solid batteries.

[0010] In most solid-state batteries, the volume of the negative electrode increases during charging due to lithium adsorption and other factors. During discharge, the volume of the negative electrode decreases due to lithium release and other factors. This increase or decrease in the volume of the negative electrode can cause a short circuit between the positive and negative conductors. Therefore, it is desirable to ensure that the insulation distance between the positive and negative conductors is as large as possible.

[0011] On the other hand, by reducing the area of ​​the positive electrode collector and the positive electrode frame when viewed in the stacking direction, the edges of the positive electrode collector and the positive electrode frame are recessed further inward than the edges of the solid electrolyte, thereby ensuring the insulation distance between the conductor on the positive electrode side and the conductor on the negative electrode side. The following problems may arise.

[0012] Specifically, when a solid-state battery is in use, the positive electrode frame cannot block the load directed toward the positive electrode from the edge of the negative electrode. Consequently, this load easily escapes to the edge of the negative electrode. Consequently, during charging, problems such as large amounts of lithium and other substances being easily adsorbed to the edge of the negative electrode can occur.

[0013] The present invention has been made in view of the above circumstances and aims to facilitate the positive electrode frame to absorb the load on the positive electrode side relative to the edge of the negative electrode and to facilitate ensuring a large insulation distance between the positive electrode side conductor and the negative electrode side conductor.

[0014] [Technical means to solve the problem]

[0015] The present inventors have discovered that the above-mentioned object can be achieved by setting the areas of the layers constituting the solid battery to have a predetermined size relationship, and have thus completed the present invention. The present invention is the solid battery of the following (1) to (12).

[0016] (1) A solid battery comprising, in order from at least one side of a 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 comprising a positive electrode tab protruding from the positive electrode current collector and a negative electrode tab protruding from the negative electrode,

[0017] A positive electrode frame is provided on the negative electrode side closer to the positive electrode current collector than the positive electrode current collector, and an insulator surrounds the positive electrode material layer.

[0018] Charging increases the volume of the negative electrode, while discharging reduces the volume of the negative electrode, wherein:

[0019] The area inside the outer edge of the positive electrode frame in a plan view seen along 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".

[0020] And the relationship of "sEc≧sF>sN≧sEn" is satisfied.

[0021] According to this structure, since "sN≧sEn" satisfies, it is easy to transfer the negative electrode side solid electrolyte layer to the negative electrode side based on the negative electrode side.

[0022] Furthermore, because "sF > sEn" (sF > sEn), the surface of the negative-side solid electrolyte layer on the positive electrode frame side tends to be flat. Furthermore, because "sF > sN" (sF > sN), the positive electrode frame tends to expand to the portion corresponding to the edge of the negative electrode. This makes it easier for the positive electrode frame to absorb the load from the edge of the negative electrode toward the positive electrode.

[0023] Furthermore, since "sEc ≧ sF", the edge of the solid electrolyte layer is more likely to protrude outward than the edge of the positive electrode frame. This makes it easier to maintain the insulation distance between the conductors on the positive and negative electrode sides by defining the solid electrolyte layer.

[0024] As described above, according to this structure, the load on the positive electrode side relative to the edge of the negative electrode can be easily blocked by the positive electrode frame, and the insulation distance between the positive electrode side conductor and the negative electrode side conductor can be easily ensured.

[0025] (2) The solid battery according to (1), further comprising an intermediate layer between the negative electrode-side solid electrolyte layer and the negative electrode.

[0026] The area of ​​the aforementioned middle layer is defined as "sM",

[0027] And satisfy the relationship of "sN≧sM≧sEn".

[0028] According to this structure, by making the intermediate layer assume the prescribed role, the performance of the solid battery can be further improved. In addition, since "sN ≧ sM", it is easy to transfer the intermediate layer to the negative electrode based on the negative electrode side. In addition, even if the intermediate layer constitutes the conductor on the negative electrode side, since "sN ≧ sM", it is easy to ensure the insulation distance between the intermediate layer and the conductor on the positive electrode side. In addition, since "sM ≧ sEn", it is easy to transfer the negative electrode side solid electrolyte layer to the intermediate layer based on the intermediate layer side.

[0029] (3) The solid battery according to (1) or (2), further comprising a positive electrode side solid electrolyte layer between the positive electrode material layer and the predetermined solid electrolyte layer.

[0030] The area of ​​the positive electrode side solid electrolyte layer in the above plan view is defined as "sEp",

[0031] And the relationship of "sEc≧sF≧sEp" is satisfied.

[0032] According to this structure, since "sF≧sEp", it is easy to transfer the positive electrode side solid electrolyte layer to the positive electrode frame side. In addition, since "sEc≧sEp", it is easy to transfer the positive electrode side solid electrolyte layer to a predetermined solid electrolyte layer.

[0033] (4) The solid state battery according to any one of (1) to (3) above, wherein the relationship "sEc>sF" is satisfied.

[0034] According to this structure, by setting the solid electrolyte layer to protrude further outward than the positive electrode frame, the insulation between the conductor on the positive electrode side and the conductor on the negative electrode side can be further improved.

[0035] (5) The solid battery according to any one of (1) to (4), wherein the predetermined solid electrolyte layer protrudes further in the protruding direction of the negative electrode tab than the positive electrode frame.

[0036] According to this structure, by defining the solid electrolyte layer, the insulation distance between the negative electrode tab and the positive electrode current collector can be ensured.

[0037] (6) The solid battery according to any one of (1) to (5), wherein the predetermined solid electrolyte layer is thicker than the negative electrode side solid electrolyte layer along the stacking direction.

[0038] According to this structure, by thickening the predetermined solid electrolyte layer having the largest area and tending to protrude outward in the stacking direction, the predetermined solid electrolyte layer can be made less susceptible to damage even under pressure loads or the like.

[0039] (7) The solid battery according to any one of (1) to (6), wherein the predetermined solid electrolyte layer includes a porous substrate and a solid electrolyte filled in the substrate.

[0040] According to this structure, by making the predetermined solid electrolyte layer include the base material, the predetermined solid electrolyte layer can be made less susceptible to damage even under pressure load or the like.

[0041] (8) The solid battery according to any one of (1) to (7), wherein the predetermined solid electrolyte layer contains a binder.

[0042] The content of the binder in the predetermined solid electrolyte layer is different from the content of the binder in the negative electrode side solid electrolyte layer.

[0043] According to this structure, by making the binder content of the predetermined solid electrolyte layer different from that of the negative electrode side solid electrolyte layer, it is easy to adjust the strength of the solid electrolyte layer to be higher. Therefore, the predetermined solid electrolyte layer can be made less susceptible to damage even under pressure loads.

[0044] (9) The solid battery according to any one of (1) to (8), wherein the solid battery comprises a positive electrode tab insulating portion, the positive electrode tab insulating portion protruding from the positive electrode frame in a protruding direction of the positive electrode tab,

[0045] The positive electrode tab insulating portion protrudes further than the solid electrolyte layer in a protruding direction of the positive electrode tab.

[0046] According to this structure, a large insulation distance between the positive electrode tab and the negative electrode can be ensured by the positive electrode tab insulating portion.

[0047] (10) The solid battery according to any one of (1) to (9), further comprising a positive electrode side solid electrolyte layer between the positive electrode material layer and the predetermined solid electrolyte layer.

[0048] An intermediate layer is provided between the anode-side solid electrolyte layer and the anode.

[0049] The area of ​​the positive electrode material layer in the plan view is defined as "sPm".

[0050] The area of ​​the positive electrode side solid electrolyte layer in the plan view is defined as "sEp".

[0051] The area of ​​the intermediate layer in the plan view is defined as "sM".

[0052] And satisfy the relationship of "sEc≧sF≧sEp≧sN≧sM≧sEn≧sPm".

[0053] According to this structure, since "sF≧sEp", it is easy to transfer the positive electrode side solid electrolyte layer to the positive electrode frame and positive electrode material layer based on the positive electrode frame side. In addition, since "sN≧sM≧", it is easy to transfer the intermediate layer to the negative electrode based on the negative electrode side. In addition, since "sM≧sEn", it is easy to transfer the negative electrode side solid electrolyte layer to the intermediate layer based on the intermediate layer side. In addition, since "sEc≧sEp", it is easy to transfer the positive electrode side solid electrolyte layer to a specified solid electrolyte layer. In addition, since "sEc≧sEn", it is easy to transfer the negative electrode side solid electrolyte layer to a specified solid electrolyte layer.

[0054] (11) A solid battery according to any one of (1) to (10) above, wherein the solid battery has a resin coating, the resin coating covers the end of the stack in a direction orthogonal to the stacking direction, and the stack includes the positive electrode collector, the positive electrode material layer, the positive electrode frame, the specified solid electrolyte layer, the negative electrode side solid electrolyte layer, and the negative electrode.

[0055] According to this structure, the resin coating can further improve the insulation between the conductor on the positive electrode side and the conductor on the negative electrode side. Furthermore, since "sEc>sEn" in (1) cited in this structure, the resin coating easily enters the area between the specified solid electrolyte layer and the negative electrode tab, including the area outside the edge of the negative electrode side solid electrolyte layer.

[0056] (12) A solid battery according to any one of (1) to (11) above, wherein the negative electrode comprises: a negative electrode current collector; and a negative electrode material layer provided on a side closer to the positive electrode current collector than the negative electrode current collector and containing metallic lithium.

[0057] According to this configuration, in this solid battery, the above-described effects are obtained.

[0058] (Effects of the Invention)

[0059] As described above, according to the structure of (1), the load on the positive electrode side relative to the edge of the negative electrode can be easily blocked by the positive electrode frame, while a large insulation distance can be ensured between the conductor on the positive electrode side and the conductor on the negative electrode side. Furthermore, according to the structures of (2) to (12) cited in (1), each additional effect is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 It is an exploded perspective view showing each layer of the solid state battery according to the first embodiment.

[0061] Figure 2 It is a plan view showing a solid-state battery.

[0062] Figure 3 It is a drawing Figure 2 A cross-sectional view of the cross section taken along the fg3-fg3 line.

[0063] Figure 4 It is a drawing Figure 2 A cross-sectional view of the cross-section taken along the fg4-fg4 line.

[0064] Figure 5 This is a cross-sectional view of the solid state battery according to the second embodiment, as viewed along the X direction.

[0065] Figure 6 This is a cross-sectional view of the solid battery viewed from the Y direction. DETAILED DESCRIPTION

[0066] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the present invention.

[0067] [First embodiment]

[0068] Figure 1 The solid-state battery Bt of the present embodiment shown is a lithium metal secondary battery having multiple layers. Hereinafter, the three directions orthogonal to each other are referred to as the "X direction," the "Y direction," and the "Z direction." Furthermore, the "Z direction" may also be referred to as the stacking direction. Hereinafter, one side in the X direction is referred to as the "X-side," and the opposite side is referred to as the "X+ side." Furthermore, one side in the Y direction is referred to as the "Y-side," and the other side in the Y direction is referred to as the "Y+ side." Furthermore, one side in the Z direction is referred to as the "Z-side," and the opposite side is referred to as the "Z+ side."

[0069] like Figure 3 As shown, 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+ and Z- sides, a positive electrode material layer Pm, a positive electrode electrolyte layer Ep, an intermediate electrolyte layer Ec, a negative electrode electrolyte layer En, an intermediate layer M, a negative electrode material layer Nm, and a negative electrode current collector Nc. Furthermore, the solid-state battery Bt further includes a positive electrode frame F, an insulator surrounding the positive electrode material layer Pm, on each side closer to the Z+ and Z- sides than the positive electrode current collector Pc.

[0070] 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. Furthermore, the "positive electrode side electrolyte layer Ep," the "intermediate electrolyte layer Ec," and the "negative electrode side electrolyte layer En" may be respectively referred to as the "positive electrode side solid electrolyte layer," the "predetermined solid electrolyte layer," and the "negative electrode side solid electrolyte layer." The negative electrode material layer Nm and the negative electrode current collector Nc constitute the negative electrode N.

[0071] Hereinafter, the plan view as viewed from the Z direction will be referred to simply as the "plan view." In addition, the area of ​​the positive electrode frame F, which is located inside the outer edge of the plan view, will be defined as "sF." The area of ​​the positive electrode material layer Pm in the plan view will be defined as "sPm." The area of ​​the positive-electrode-side electrolyte layer Ep in the plan view will be defined as "sEp." The area of ​​the intermediate electrolyte layer Ec in the plan view will be defined as "sEc." The area of ​​the negative-electrode-side solid electrolyte layer E in the plan view will be defined as "sEn." The area of ​​the intermediate layer M in the plan view will be defined as "sM." The area of ​​the negative electrode N in the 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 the plan view. In this embodiment, since the area of ​​the negative electrode current collector layer Nc in the plan view is greater than the area of ​​the negative electrode material layer Nm, "sN" is essentially the area of ​​the negative electrode current collector layer Nc in the plan view.

[0072] The solid-state battery Bt also includes a positive electrode tab Tp that protrudes from the positive electrode current collector Pc toward the Y+ side. Therefore, the "Y+ side" can also be replaced by the "direction of protrusion of the positive electrode tab Tp." Furthermore, the positive electrode P and the positive electrode tab Tp constitute the conductor on the positive electrode P side. Furthermore, the solid-state battery Bt also includes a positive electrode tab insulating portion Ip that protrudes from the positive electrode frame F toward the Y+ side. Furthermore, the area of ​​the positive electrode tab insulating portion Ip is not included in "sF." Furthermore, the solid-state battery Bt also includes a negative electrode tab Tn that protrudes from the negative electrode current collector Nc toward the Y- side. Therefore, the "Y- side" can also be replaced by the "direction of protrusion of the negative electrode tab Tn." Furthermore, 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 the conductor on the negative electrode N side.

[0073] Next, details of each layer of the solid state battery Bt will be described in order from the positive electrode P side.

[0074] Specific examples of the material constituting the positive electrode current collector Pc include aluminum foil, etc. The positive electrode tab Tp is formed integrally with the positive electrode current collector Pc.

[0075] The positive electrode material layer Pm contains a positive electrode active material that is a material capable of absorbing and releasing lithium. Specific examples of the positive electrode active material include LiCoO2, Li(Ni 5 / 10 Co 2 / 10 Mn 3 / 10 )O2、Li(Ni 6 / 10 Co 2 / 10 Mn 2 / 10 )O2、Li(Ni 8 / 10 Co 1 / 10 Mn 1 / 10 )O2、Li(Ni 0.8 Co 0.15 Al 0.05 )O2、Li(Ni 1 / 6 Co 4 / 6 Mn 1 / 6 )O2、Li(Ni 1 / 3 Co 1 / 3 Mn 1 / 3 )O2, LiCoO4, LiMn2O4, LiNiO2, LiFePO4, lithium sulfide, sulfur, etc. The positive electrode material layer Pm may further include a solid electrolyte, a conductive additive, a binder, etc. The positive electrode material layer Pm is located inside the positive electrode frame F. Therefore, among "sPm", "sF", "sEp", "sEc", "sEn", "sM", and "sN", "sPm" is the smallest.

[0076] like Figure 1As shown, the positive electrode frame F is a quadrilateral in plan view. Specific examples of materials for the positive electrode frame F include insulating oxides such as alumina, resins such as polyvinylidene difluoride (PVDF), and rubbers such as styrene-butadiene rubber (SBR). The positive electrode tab insulation portion Ip is integrally formed with the positive electrode frame F.

[0077] Figure 3 The solid electrolyte layer E shown includes a solid electrolyte capable of conducting lithium ions. Specific examples of the solid electrolyte include oxide-based electrolytes and sulfide-based electrolytes. Furthermore, the solid electrolyte layer E contains a binder.

[0078] The positive electrode-side electrolyte layer Ep is transferred to the positive electrode material layer Pm and the positive electrode frame F based on the positive electrode P side. Thus, the relationship "sF ≧ sEp" is satisfied. Furthermore, the positive electrode-side electrolyte layer Ep is subsequently transferred to the intermediate electrolyte layer Ec. Thus, the relationship "sEc ≧ sEp" is also satisfied.

[0079] The intermediate electrolyte layer Ec is the primary layer in the solid electrolyte layer E and is thicker in the Z direction than either the positive electrode electrolyte layer Ep or the negative electrode electrolyte layer En. The intermediate electrolyte layer Ec comprises a porous substrate, such as a nonwoven fabric, and the aforementioned solid electrolyte filled within the substrate. The binder content of the intermediate electrolyte layer Ec differs from that of the negative electrode solid electrolyte layer E. In this embodiment, to ensure the insulation distance between the conductor on the positive electrode P side and the conductor on the negative electrode N side, the intermediate electrolyte layer Ec satisfies the relationship "sEc > sF."

[0080] The negative electrode side electrolyte layer En is transferred to the intermediate layer M based on the intermediate layer M side. Thus, the relationship "sM ≧ sEn" is satisfied. Furthermore, the negative electrode side electrolyte layer En is subsequently transferred to the intermediate electrolyte layer Ec. Thus, the relationship "sEc ≧ sEn" is also satisfied.

[0081] Specific examples of materials constituting the intermediate layer M include carbon loaded with a metal capable of alloying with lithium (e.g., silver). The intermediate layer M stabilizes the interface between the solid electrolyte layer E and the intermediate layer M, and also stabilizes 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. Thus, the relationship "sN ≧ sM" is satisfied. Furthermore, since "sN ≧ sM" is thus established, it is easy to ensure the insulation distance between the intermediate layer M and the conductor on the positive electrode P side.

[0082] The negative electrode material layer Nm contains a negative electrode active material that is a substance 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, carbon materials, and the like. Examples of the carbon material include artificial graphite, natural graphite, hard carbon, and soft carbon. The negative electrode material layer Nm may further include a solid electrolyte, a conductive additive, a binder, and the like. Therefore, the negative electrode material layer Nm may be, for example, a layer containing metallic lithium as a main component, or a layer containing silicon as a main component.

[0083] Specific examples of materials for the negative electrode current collector Nc include copper foil. The negative electrode tab Tn is integrally formed with the negative electrode current collector Nc. This negative electrode current collector Nc is formed within a range that satisfies the relationship "sF > sN" for insulation performance with the positive electrode tab Tp.

[0084] As described above, in this embodiment, the relationship of "sEc>sF≧sEp≧sN≧sM≧sEn≧sPm" is satisfied. In addition, in this embodiment, the relationship of "sF>sN" is satisfied.

[0085] Next, refer to Figure 3 The left portion of the solid battery Bt illustrates the positional relationship between the Y+ side ends of each layer. The negative electrode side electrolyte layer En, the intermediate layer M, the negative electrode material layer Nm, and the negative electrode collector Nc each protrude further toward the Y+ side than the positive electrode material layer Pm. The positive electrode collector Pc, the positive electrode frame F, the positive electrode side electrolyte layer Ep, and the intermediate electrolyte layer Ec each protrude further toward the Y+ side than the layers En, M, Nm, and Nc. The positive electrode tab insulating portion Ip protrudes further toward the Y+ direction than the layers Pc, F, Ep, and Ec. The positive electrode tab Tp protrudes further toward the Y+ side than the positive electrode tab insulating portion Ip. In addition, the protruding length of the positive electrode tab insulating portion Ip toward the Y+ side relative to the intermediate electrolyte layer Ec is approximately 0.3 to 1.0 mm.

[0086] Next, refer to Figure 3 The right portion of the figure illustrates the positional relationship between the Y-side ends of each layer of the solid-state battery Bt. The negative-electrode electrolyte layer En, the intermediate layer M, the negative-electrode material layer Nm, and the negative-electrode current collector Nc each protrude further toward the Y-side than the positive-electrode material layer Pm. The positive-electrode current collector Pc, the positive-electrode frame F, and the positive-electrode electrolyte layer Ep each protrude further toward the Y-side than the layers En, M, Nm, and Nc. The intermediate electrolyte layer Ec protrudes further toward the Y-side than the layers Pc, F, and Ep. Furthermore, the length of the intermediate electrolyte layer Ec protruding toward the Y-side relative to the positive-electrode frame F is approximately 0.3 to 2.0 mm.

[0087] Next, refer to Figure 4, the positional relationship between the ends in the X direction in each layer of the solid battery Bt is described. Figure 4 Only the X+ side end portion of each layer of the solid battery Bt is shown, and the X- side end portion is not shown. Figure 4 If the end portion on the X+ side shown is reversed with the Z direction as an axis, the end portion on the X- side will be the same.

[0088] 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 further outward in the X direction than 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 further outward in the X direction than the layers M, En, Nc, and Nm.

[0089] Next, the manufacturing method of the solid battery Bt shown above is described. This manufacturing method includes a positive electrode manufacturing process, a negative electrode manufacturing process, and an overall manufacturing process. The positive electrode manufacturing process and the negative electrode manufacturing process can be performed one by one or in parallel. On the other hand, the overall manufacturing process is performed after the positive electrode manufacturing process and the negative electrode manufacturing process. In addition, the "transfer" mentioned below is performed using a roller press or the like.

[0090] In the positive electrode manufacturing process, the material including the positive electrode side electrolyte layer Ep is transferred to both surfaces in the Z direction of the material including the positive electrode collector Pc, the positive electrode tab Tp, the positive electrode material layer Pm, and the positive electrode frame F.

[0091] In the negative electrode manufacturing process, first, the material including the intermediate layer M is transferred to the material including the negative electrode current collector Nc, the negative electrode tab Tn, and the negative electrode material layer Nm. Next, the material including the negative electrode side electrolyte layer En is transferred to the material including the negative electrode current collector Nc, the negative electrode tab Tn, the negative electrode material layer Nm, and the intermediate layer M.

[0092] In the overall manufacturing process, the material including the intermediate electrolyte layer Ec is first transferred onto both sides of the Z-direction surface of the material produced in the positive electrode manufacturing process. Next, the material produced in the negative electrode manufacturing process is further transferred onto both sides of the transferred material in the Z-direction. The material to which these materials have been transferred is then cut, completing the internal structure of the solid-state battery Bt.

[0093] The internal structure of the solid battery Bt manufactured in the above manner 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. As a result, when the solid battery Bt is in use, the positive electrode P is always pressed against the negative electrode N, and the negative electrode N is always pressed against the positive electrode P.

[0094] During use, the solid-state battery Bt repeatedly charges and discharges from a predetermined fully charged state to a predetermined fully discharged state. During charging, the solid-state battery Bt absorbs lithium into the negative electrode material layer Nm, increasing the volume of the negative electrode N. Conversely, during discharging, lithium is released from the negative electrode material layer Nm, decreasing the volume of the negative electrode N.

[0095] 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, this negative electrode expansion rate can be appropriately varied, for example, within a range of 1.8 times or more and 5.5 times or less.

[0096] Hereinafter, the configuration and effects of this embodiment will be summarized.

[0097] The relationship "sEc>sF≧sEp≧sN≧sM≧sEn≧sPm" is satisfied. Because "sF≧sEp" is established, 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 based on the positive electrode frame F side. In addition, because "sN≧sM" is established, it is easy to transfer the intermediate layer M to the negative electrode N based on the negative electrode N side. In addition, because "sM≧sEn" is established, it is easy to transfer the negative electrode side electrolyte layer En to the intermediate layer M based on the intermediate layer M side. In addition, because "sEc>sEp" is established, it is easy to transfer the positive electrode side electrolyte layer Ep to the intermediate electrolyte layer Ec. In addition, because "sEc>sEn" is established, it is easy to transfer the negative electrode side electrolyte layer En to the intermediate electrolyte layer Ec.

[0098] Because "sF>sEn" is true, the surface of the positive electrode frame F on the negative-electrolyte layer En is easily flattened. Furthermore, because "sF>sN" is true, the positive electrode frame F easily expands to the portion corresponding to the edge of the negative electrode N. As a result, the load directed toward the positive electrode P from the edge of the negative electrode N is easily blocked by the positive electrode frame F. This reduces the risk of this load escaping to the edge of the negative electrode N. This also reduces the risk of a high amount of lithium being adsorbed at the edge of the negative electrode material layer Nm during charging.

[0099] Furthermore, due to "sEc>sF", the edge of the intermediate electrolyte layer Ec protrudes further outward than the edge of the positive electrode frame F. Thus, the intermediate electrolyte layer Ec facilitates ensuring the insulation distance between the conductor on the positive electrode P side and the conductor on the negative electrode N side.

[0100] The intermediate electrolyte layer Ec protrudes further in the Y-direction than the positive electrode frame F. The intermediate electrolyte layer Ec ensures an insulation distance between the negative electrode tab Tn and the positive electrode current collector Pc.

[0101] The intermediate electrolyte layer Ec is thicker than either the positive-electrode electrolyte layer Ep or the negative-electrode electrolyte layer En in the stacking direction Z. By thickening the intermediate electrolyte layer Ec, which has the largest area and protrudes most outward in the Z direction, the intermediate electrolyte layer Ec is less susceptible to damage even under compressive loads.

[0102] 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 is less susceptible to damage even under pressure loads.

[0103] The binder content of the intermediate electrolyte layer Ec differs from that of the negative-electrode electrolyte layer En. This makes it easier to adjust the strength of the intermediate electrolyte layer Ec to a higher level. Consequently, even under compressive loads, the intermediate electrolyte layer Ec is less likely to be damaged.

[0104] The positive electrode tab insulating portion Ip protrudes further toward the Y+ side than the intermediate electrolyte layer Ec. This positive electrode frame F can ensure a large insulation distance between the positive electrode tab Tp and the negative electrode N.

[0105] [Second embodiment]

[0106] Next, refer to Figure 5 、 Figure 6 This embodiment will be described based on the first embodiment, focusing on the differences therefrom, and appropriately omitting descriptions of aspects identical or similar to those of the first embodiment.

[0107] The following, such as Figure 5 As shown, the main part of the solid battery Bt is called a "stack L". Specifically, the stack L includes a positive electrode P and a positive electrode frame F, and includes a solid electrolyte layer E, an intermediate layer M, and a negative electrode N provided on both sides thereof in the Z direction.

[0108] The solid battery Bt further includes a resin coating RC that covers the ends of the stack L in the X and Y directions. Specifically, the resin coating RC covers the end of the stack L on the Y+ side from the Y+ side, and covers the end of the stack L on the Y- side from the Y- side. Figure 6 As shown, the resin coating layer RC covers the end portion on the X+ side of the stacked body from the X+ side, and covers the end portion on the X- side of the stacked body L from the X- side.

[0109] According to this embodiment, the insulation between the conductor on the positive electrode P side and the conductor on the negative electrode N side can be further improved by the resin coating RC. Figure 5As shown, due to "sEc>sEn", the resin coating RC can easily enter the region between the intermediate electrolyte layer Ec and the negative electrode tab Tn, including the region outside the edge of the negative electrode side electrolyte layer En.

[0110] [Other embodiments]

[0111] The above-described embodiments may be modified as follows, for example. 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. If 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 not be required.

[0112] The negative electrode N may also be a non-anode having no negative electrode material layer Nm immediately after manufacture. In this case, a lithium metal layer serving as the negative electrode material layer Nm is formed after the initial charge. Furthermore, the solid-state battery Bt may be a battery other than a lithium metal secondary battery. In this case, the intermediate layer M for uniform lithium metal deposition may also be omitted.

[0113] Even if “sEc=sF”, when the insulation between the positive electrode P and the negative electrode N can be sufficiently ensured, “sEc=sF” may be set.

[0114] Reference numerals

[0115] Bt solid-state battery

[0116] Ec Intermediate electrolyte layer (specified solid electrolyte layer)

[0117] En Negative electrode side electrolyte layer (negative electrode side solid electrolyte layer)

[0118] Ep positive electrode side electrolyte layer (positive electrode side solid electrolyte layer)

[0119] F Positive frame

[0120] Ip positive electrode tab insulation part

[0121] M Middle Layer

[0122] N negative electrode

[0123] Nc negative electrode current collector

[0124] Nm negative electrode material layer

[0125] P positive electrode

[0126] Pc positive electrode collector

[0127] Pm positive electrode material layer

[0128] Tn negative electrode tab

[0129] Tp positive electrode tab

[0130] RC resin coating

Claims

1. A solid battery comprising, in order from at least one side of a 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 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 is provided on the negative electrode side closer to the positive electrode current collector than the positive electrode current collector, and an insulator surrounds the positive electrode material layer. Charging increases the volume of the negative electrode, while discharging reduces the volume of the negative electrode. The solid battery is characterized in that: The area inside the outer edge of the positive electrode frame in the plan view along 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". And the relationship of "sEc≧sF>sN≧sEn" is satisfied.

2. The solid state battery according to claim 1, wherein An intermediate layer is provided between the anode-side solid electrolyte layer and the anode. The area of ​​the aforementioned middle layer is defined as "sM", And satisfy the relationship "sN≧sM≧sEn".

3. The solid state battery according to claim 1 or 2, wherein A positive electrode side solid electrolyte layer is provided between the positive electrode material layer and the predetermined solid electrolyte layer. The area of ​​the positive electrode side solid electrolyte layer in the above plan view is defined as "sEp", And satisfy the relationship "sEc≧sF≧sEp".

4. The solid state battery according to claim 1 or 2, wherein The relationship "sEc>sF" is satisfied.

5. The solid state battery according to claim 1 or 2, wherein The predetermined solid electrolyte layer protrudes further in a protruding direction of the negative electrode tab than the positive electrode frame.

6. The solid state battery according to claim 1 or 2, wherein: The predetermined solid electrolyte layer is thicker than the negative electrode side solid electrolyte layer along the stacking direction.

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

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

9. The solid state battery according to claim 1 or 2, wherein The solid battery includes a positive electrode tab insulating portion, the 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 solid electrolyte layer in a protruding direction of the positive electrode tab.

10. The solid state battery according to claim 1 or 2, wherein A positive electrode side solid electrolyte layer is provided between the positive electrode material layer and the predetermined solid electrolyte layer. An intermediate layer is provided between the anode-side solid electrolyte layer and the anode. 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", And satisfy the relationship "sEc≧sF≧sEp≧sN≧sM≧sEn≧sPm".

11. The solid state battery according to claim 1 or 2, wherein The solid battery has a resin coating, which covers the end of the stack on the side perpendicular to the aforementioned stacking direction, and the stack includes the aforementioned positive electrode collector, the aforementioned positive electrode material layer, the aforementioned positive electrode frame, the aforementioned specified solid electrolyte layer, the aforementioned negative electrode side solid electrolyte layer, and the aforementioned negative electrode.

12. The solid state battery according to claim 1 or 2, wherein: The negative electrode includes: a negative electrode current collector; and a negative electrode material layer provided on the positive electrode current collector side relative to the negative electrode current collector and containing metallic lithium.

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