All-solid battery

Abstract

To provide an all-solid battery that suppresses displacement of a battery unit without reducing the structural efficiency of a battery.SOLUTION: An all-solid battery includes a stack of a plurality of battery units each including, in this order, a first current collector layer, an electrode layer, a second current collector layer, an electrode layer, and a first current collector layer, the stack including a battery unit X and a battery unit Y adjacent to each other, and a fixing portion that fixes the battery unit X and the battery unit Y together, and the fixing portion is in contact with the electrode layer of the battery unit X and the electrode layer of the battery unit Y.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present disclosure relates to all-solid-state batteries. [Background technology]

[0002] All-solid-state batteries that use a solid electrolyte instead of an electrolytic solution in which an electrolyte is dissolved in an organic solvent are being developed. One example of a method for manufacturing an all-solid-state battery is a method in which multiple pre-fabricated battery units are stacked. Batteries obtained by stacking multiple battery units are prone to misalignment of the battery units due to vibration during use and expansion and contraction during charging and discharging. Misalignment of the battery units may cause short circuits and other problems. As a measure to prevent misalignment between battery units, Patent Document 1 proposes an all-solid-state battery having an adhesive means for fixing adjacent battery units with an adhesive. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-204377 Summary of the Invention [Problem to be solved by the invention]

[0004] In the all-solid-state battery described in Patent Document 1, adhesive means are provided on the opposing surfaces of adjacent battery units, which may limit the number of battery units that can be accommodated in a battery case due to the adhesive means disposed between multiple battery units, resulting in a risk of reducing the structural efficiency of the battery. An object of one embodiment of the present disclosure is to provide an all-solid-state battery in which displacement of a battery unit is suppressed without reducing the structural efficiency of the battery. [Means for solving the problem]

[0005] The means for solving the above problems include the following embodiments. <1> a stack of a plurality of battery units each including a first current collector layer, an electrode layer, a second current collector layer, an electrode layer, and a first current collector layer in this order; the stack includes a battery unit X and a battery unit Y adjacent to each other, and a fixing portion that fixes the battery unit X and the battery unit Y, The fixing portion is in contact with the electrode layer of the battery unit X and the electrode layer of the battery unit Y, respectively. <1> the fixing portion is in contact with an end surface of the first current collector layer of the battery unit X and an end surface of the first current collector layer of the battery unit Y, <1> The all-solid-state battery described in <3> the electrode layer of the battery unit X and the electrode layer of the battery unit Y each include a first active material layer adjacent to a first current collector layer, a solid electrolyte layer, and a second active material layer adjacent to a second current collector layer; the fixing portion is in contact with the first active material layer of the battery unit X and the first active material layer of the battery unit Y, <1> or <2> The all-solid-state battery described in <4> the electrode layer of the battery unit X and the electrode layer of the battery unit Y each include a first active material layer adjacent to a first current collector layer, a solid electrolyte layer, and a second active material layer adjacent to a second current collector layer; the fixing portion is in contact with the solid electrolyte layer of the battery unit X and the solid electrolyte layer of the battery unit Y, <1> or <2> The all-solid-state battery described in <5> The fixing portion includes a resin. <1> ~ <4> 10. The all-solid-state battery according to claim 1, [Effects of the Invention]

[0006] According to one embodiment of the present disclosure, an all-solid-state battery is provided in which displacement of a battery unit is suppressed without reducing the structural efficiency of the battery. [Brief explanation of the drawings]

[0007] [Figure 1A] 1 is a cross-sectional view schematically illustrating an example of the configuration of a battery unit X and a battery unit Y adjacent to each other among the battery units included in an all-solid-state battery. FIG. [Figure 1B] 1B is a plan view schematically illustrating the configuration of the battery unit X shown in FIG. 1A when viewed from the main surface side of the first current collector layer 10. FIG. [Figure 2A] 1 is a cross-sectional view schematically illustrating an example of the configuration of a battery unit X and a battery unit Y adjacent to each other among the battery units included in an all-solid-state battery. FIG. [Figure 2B] 2B is a plan view schematically illustrating the configuration of the battery unit X shown in FIG. 2A when viewed from the main surface side of the first current collector layer 10. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] The all-solid-state battery of the present disclosure comprises: a stack of a plurality of battery units each including a first current collector layer, an electrode layer, a second current collector layer, an electrode layer, and a first current collector layer in this order; the stack includes a battery unit X and a battery unit Y adjacent to each other, and a fixing portion that fixes the battery unit X and the battery unit Y, The fixing portion is an all-solid-state battery that is in contact with the electrode layer of the battery unit X and the electrode layer of the battery unit Y, respectively.

[0009] The all-solid-state battery of the present disclosure is a so-called stacked battery that includes a stack of multiple battery units. The stack includes a battery unit X and a battery unit Y adjacent to each other, and a fixing portion that fixes the battery unit X and the battery unit Y together. That is, at least some of the battery units included in the stack are fixed to adjacent battery units by fixing portions.

[0010] In the all-solid-state battery of the present disclosure, the fixing portion is in contact with the electrode layer of battery unit X and the electrode layer of battery unit Y. That is, the all-solid-state battery of the present disclosure differs from existing all-solid-state batteries in that the fixing portion is not located between the first electrode layer of battery unit X and the first electrode layer of battery unit Y. In the all-solid-state battery of the present disclosure, the influence of the thickness of the fixing part on the dimension in the stacking direction of the battery units is reduced compared to when the fixing part is disposed between the first electrode layer of battery unit X and the first electrode layer of battery unit Y. As a result, a sufficient number of battery units can be accommodated in the battery case, and a decrease in the structural efficiency of the battery is suppressed.

[0011] In the following description, the battery unit X and the battery unit Y may be referred to as the "battery unit" without distinction. The battery unit constituting the laminate includes, in this order, a first current collector layer, an electrode layer, a second current collector layer, an electrode layer, and a first current collector layer. The first current collector layer and the second current collector layer are opposite poles to each other, i.e., when the first current collector layer is a negative electrode current collector layer, the second current collector layer is a positive electrode current collector layer, and when the first current collector layer is a positive electrode current collector layer, the second current collector layer is a negative electrode current collector layer.

[0012] From the viewpoint of more reliably suppressing misalignment of the battery units, it is preferable that the fixing portion that fixes the battery unit X and the battery unit Y contact the end surface of the first current collector layer of the battery unit X and the end surface of the first current collector layer of the battery unit Y, respectively.

[0013] From the viewpoint of effectively suppressing a decrease in the structural efficiency of the all-solid-state battery, it is preferable that the fixing portion be disposed in a portion that is inside the outer periphery of the stack when the stack of the battery unit is observed from above in the stacking direction.

[0014] Of the multiple battery units included in the stack, all or some of them may satisfy the conditions of battery unit X and battery unit Y. That is, all of the battery units included in the stack may be fixed to adjacent battery units by fixing portions, or only some of the battery units may be fixed to adjacent battery units by fixing portions. From the viewpoint of effectively suppressing misalignment of the battery units, it is more preferable that 50% to 100%, 70% to 100%, or 80% to 100% of the battery units included in the stack satisfy the conditions of battery unit X and battery unit Y, based on the number of units.

[0015] The electrode layers included in the battery unit may include a first active material layer adjacent to the first current collector layer, a solid electrolyte layer, and a second active material layer adjacent to the second current collector layer. When the first current collector layer is a negative electrode current collector layer, the first active material layer is a layer containing a negative electrode active material, and when the first current collector layer is a positive electrode current collector layer, the first active material layer is a layer containing a positive electrode active material. When the second current collector layer is a negative electrode current collector layer, the second active material layer is a layer containing a negative electrode active material, and when the second current collector layer is a positive electrode current collector layer, the second active material layer is a layer containing a positive electrode active material.

[0016] Hereinafter, the first active material layer and the second active material layer may be referred to as "active material layer" without distinction. The active material layer is a layer containing at least an active material, and the solid electrolyte layer is a layer containing at least a solid electrolyte. The active material layer may contain a solid electrolyte together with an active material.

[0017] The fixing portion that fixes the battery unit X and the battery unit Y may be in contact with any layer included in the electrode layer. For example, the following embodiments 1 to 3 are exemplified. In embodiments 1 to 3, the fixing portion may also be in contact with another layer included in the electrode layer. Aspect 1: An aspect in which the fixing portion is in contact with the first active material layer of battery unit X and the first active material layer of battery unit Y, respectively Aspect 2: An aspect in which the fixing portion is in contact with the first active material layer of battery unit X and the first active material layer of battery unit Y, respectively Aspect 3: An aspect in which the fixing portion is in contact with the second active material layer of battery unit X and the second active material layer of battery unit Y, respectively

[0018] The material of the fixing portion is not particularly limited as long as it can fix the battery unit X and the battery unit Y together. From the viewpoint of more reliably fixing the battery unit X and the battery unit Y together, it is preferable that the fixing portion be in a state of being adhered to the electrode layer of the battery unit X and the electrode layer of the battery unit Y. A fixing portion containing a resin can be used as the fixing portion adhered to the electrode layer of the battery unit X and the electrode layer of the battery unit Y. The fixing portion containing a resin is formed by applying a material containing a resin, such as a hot melt adhesive or a solution obtained by dissolving a binder in a solvent, to a predetermined portion of at least one of the electrode layer of the battery unit X or the electrode layer of the battery unit Y.

[0019] When the fixing part contains a resin, the type of resin is not particularly limited. Specific examples of resins include polyolefins such as polyethylene (PE) and polypropylene (PP), ethylene-vinyl acetate copolymer (EVA), styrene-isoprene-styrene block copolymer (SIS), polyvinylidene fluoride (PVDF), carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), acrylic resin, polyurethane, polyester, and polyamide.

[0020] The method for applying the material of the fixing portion to the electrode layer of the battery unit is not particularly limited, and can be selected from known methods such as coating, printing, transfer, and inkjet. If necessary, after the material for the fixing portion is applied to the electrode layer of the battery unit, treatment such as heating or pressure may be carried out.

[0021] From the viewpoint of more reliably suppressing displacement of the battery unit, it is preferable that the portion to which the material for the fixing portion is applied be adjacent to the end face of the first current collector layer that is disposed on the electrode layer to which the material for the fixing portion is applied. From the viewpoint of effectively suppressing a decrease in the structural efficiency of the all-solid-state battery, it is preferable that the portion to which the material of the fixing portion is applied be a portion that is inside the outer periphery of the battery unit when the battery unit is observed from above in the stacking direction.

[0022] An example of the configuration of an all-solid-state battery according to the present disclosure will be described below with reference to the drawings. The dimensions and shapes of the components shown in the drawings are conceptual, and the actual configuration is not limited to these.

[0023] FIG. 1A is a cross-sectional view that schematically illustrates an example of the configuration of adjacent battery units X and Y among the battery units included in the all-solid-state battery of the present disclosure.

[0024] The battery unit X and battery unit Y shown in FIG. 1A each have a first current collector layer 10, an electrode layer 20, a second current collector layer 30, an electrode layer 20, and a first current collector layer 10 stacked in this order. Electrode layers 20 are disposed on both sides of the first current collector layer 10. Each electrode layer 20 is formed by laminating a first active material layer 22 adjacent to the first current collector layer 10, a solid electrolyte layer 24, and a second active material layer 26 adjacent to the second current collector layer 30 in this order.

[0025] As shown in FIG. 1A, the first current collector layer 10 and the second current collector layer 20 included in the battery unit X and the battery unit Y protrude in different directions. In FIG. 1A, the region where the first current collector layer protrudes is referred to as the first protruding region R1, the region where the second current collector layer protrudes is referred to as the second protruding region R2, and the region between the first protruding region R1 and the second protruding region R2 is referred to as the intermediate region R3. In the first projecting region R1 and the second projecting region R2, the first current collector layer 10 does not overlap with the second current collector layer 30 in the stacking direction LD.

[0026] 1A, the second current collector layer 30 included in the battery unit X and the battery unit Y has an end surface on the first protruding region R1 side covered with an insulating portion 50. The insulating portion 50 prevents the second current collector layer 30 from contacting (short-circuiting) with the first current collector layer 10.

[0027] 1A, the battery unit X and the battery unit Y have a portion (hereinafter also referred to as a clearance) where the electrode layer 20 and the first current collector layer 10 do not overlap in the stacking direction LD. The fixing portion 40 is disposed in the clearance between the battery unit X and the battery unit Y, and is in contact with the electrode layer 20 (first active material layer 22 in FIG. 1A) of the battery unit X and the electrode layer 20 (first active material layer 22 in FIG. 1A) of the battery unit Y, respectively. The fixing portion 40 shown in FIG. 1A is disposed near the boundary between the intermediate region R3 and the second protruding region R2.

[0028] FIG. 1B is a plan view that schematically illustrates the configuration of the battery unit X shown in FIG. 1A when viewed from the main surface side of the first current collector layer 10. As shown in FIG. 1B, the first current collector layer 10 of the battery unit X has a protruding shape in a portion corresponding to the first protruding region R1. The fixing portion 40 is disposed in a portion (clearance) where the first active material layer 22 included in the electrode layer 20 is exposed. Clearances are provided on the side of the first current collector layer 10 where the protruding portion is located and on the side opposite to the side where the first current collector layer 10 has the protruding portion. The fixing portion 40 shown in FIG. 1B is disposed in the clearance on the side opposite to the side where the protruding portion of the first current collector layer 10 is located.

[0029] FIG. 2A is a cross-sectional view that schematically illustrates an example of the configuration of adjacent battery units X and Y among the battery units included in the all-solid-state battery of the present disclosure. In the configuration shown in FIG. 2A, unlike the configuration (see FIG. 1A) in which the fixing portion 40 is arranged near the boundary between the intermediate region R3 of the battery unit and the second protruding region R2, the fixing portion 40 is arranged near the boundary between the intermediate region R2 of the battery unit and the first protruding region R1.

[0030] FIG. 2B is a plan view that schematically shows the configuration of the battery unit X shown in FIG. 2A when viewed from the main surface side of the first current collector layer 10. As shown in FIG. In the configuration shown in Figure 2B, unlike the configuration (see Figure 1B) in which the fixing part 40 is arranged in the clearance on the side opposite to the side having the protruding part of the first current collector layer 10, the fixing part 40 is arranged in the clearance on the side having the protruding part of the first current collector layer 10.

[0031] In the above-described drawings, the fixing portion 40 is in contact with the first active material layer 22 included in the electrode layer 20 of the battery unit X and the battery unit Y, but the embodiment of the present disclosure is not limited thereto. For example, the fixing portion 40 may be in contact with the solid electrolyte layer 24 or the second active material layer 26 included in the electrode layer 20 of the battery unit X and the battery unit Y. In the above-described drawings, the number of fixing parts 40 included in each of the battery units X and Y is two, but the embodiment of the present disclosure is not limited to this. For example, the number of fixing parts 40 per battery unit may be one, three or more.

[0032] As shown in the above-mentioned drawings, the fixing portion 40 may be arranged on the side of the battery unit where the first current collector layer does not protrude (see FIGS. 1A and 1B), or on the side of the battery unit where the first current collector layer protrudes (see FIGS. 12 and 2B). From the viewpoint of preventing the occurrence of short circuits due to expansion and contraction of the battery unit while also preventing the battery unit from shifting in position, it is preferable that the fixing portion be disposed on the side of the battery unit where the first current collector layer does not protrude. The amount of change in dimensions due to expansion of the battery unit is proportional to the size of the battery unit from the position where the fixing part is located, so displacement due to expansion of the battery unit is more likely to occur on the side of the battery unit where the fixing part is not located. 1A and 1B, the degree of expansion of the battery unit is relatively large on the side where the fixing portion is not arranged (i.e., the side where the second current collector layer protrudes). On the other hand, the end face on the side where the second current collector layer does not protrude can be insulated by covering it with an insulating portion during fabrication of the battery unit. Therefore, the risk of a short circuit on the side where the second current collector layer protrudes is easily reduced even if the battery unit expands.

[0033] Components of the battery unit included in the all-solid-state battery of the present disclosure will be described below, although the all-solid-state battery of the present disclosure is not limited thereto.

[0034] The battery unit includes, in this order, a first current collector layer, an electrode layer, a second current collector layer, an electrode layer, and a first current collector layer. When the first current collector layer is a negative electrode current collector layer, the second current collector layer is a positive electrode current collector layer, and when the first current collector layer is a positive electrode current collector layer, the second current collector layer is a negative electrode current collector layer. Examples of materials for the negative electrode current collector layer or the positive electrode current collector layer include metals such as Ag, Cu, Au, Al, Ni, Fe, and Ti, and alloys containing these metals. The material of the negative electrode current collector layer is preferably Cu or Ni, and the material of the positive electrode current collector layer is preferably Al.

[0035] The electrode layers included in the battery unit include a first active material layer adjacent to the first current collector layer, a solid electrolyte layer, and a second active material layer adjacent to the second current collector layer. When the first current collector layer is a negative electrode current collector layer, the first active material layer is a layer containing a negative electrode active material, and when the first current collector layer is a positive electrode current collector layer, the first active material layer is a layer containing a positive electrode active material. When the second current collector layer is a negative electrode current collector layer, the second active material layer is a layer containing a negative electrode active material, and when the second current collector layer is a positive electrode current collector layer, the second active material layer is a layer containing a positive electrode active material.

[0036] The negative electrode active material can be selected from materials that can absorb and release metal ions such as lithium ions. Specific examples of the negative electrode active material include metallic lithium, lithium alloys, carbon materials such as graphite and hard carbon, metal alloys, silicon materials such as silicon alloys, and Li4Ti5O 12 (LTO), etc.

[0037] Specific examples of the positive electrode active material include metal oxides containing lithium and transition metals such as manganese, cobalt, nickel, and titanium, such as lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt manganese oxide, heteroelement-substituted Li-Mn spinel, lithium titanate, and lithium metal phosphate.

[0038] Examples of the solid electrolyte include sulfide-based amorphous solid electrolytes, oxide-based amorphous solid electrolytes, sulfide-based crystalline solid electrolytes, oxide-based crystalline solid electrolytes, iodide-based crystalline solid electrolytes, and nitride-based solid electrolytes.

[0039] If necessary, each layer constituting the electrode layer may contain components other than the active material or solid electrolyte, such as a binder and a conductive material.

[0040] The thickness of the laminate consisting of a plurality of battery units is not particularly limited and can be set depending on the application and performance of the all-solid-state battery. For example, the thickness of the laminate can be selected from the range of 1 mm to 100 mm.

[0041] A laminate consisting of a plurality of battery units may be housed in an exterior body. The material of the exterior body that houses the laminate is not particularly limited and can be selected depending on the application and performance of the all-solid-state battery. In an embodiment, the exterior body may be one that includes a base layer and a barrier layer (a laminate film). The material of the substrate layer is not particularly limited, and examples thereof include thermoplastic resins, metals, etc. Examples of the barrier layer include metal foils, vapor deposition layers, etc.

[0042] The number of battery units included in the laminate is not particularly limited, and can be selected depending on the scale, performance, etc. of the all-solid-state battery. For example, the number of battery units included in the stack may be selected from within the range of 10 to 100.

[0043] The thickness of the all-solid-state battery including the stack of battery units is not particularly limited, and can be set depending on the application and performance of the all-solid-state battery. For example, the thickness of the all-solid-state battery can be selected from the range of 1 mm to 100 mm. [Explanation of symbols]

[0044] 10: First current collector layer 20: Electrode layer 22: First active material layer 24: Solid electrolyte layer 26: Second active material layer 30: Second current collector layer 40: Fixed part 50: Insulation part

Claims

1. a stack of a plurality of battery units each including a first current collector layer, an electrode layer, a second current collector layer, an electrode layer, and a first current collector layer in this order; the stack includes a battery unit X and a battery unit Y adjacent to each other, and a fixing portion that fixes the battery unit X and the battery unit Y, The fixing portion is in contact with the electrode layer of the battery unit X and the electrode layer of the battery unit Y, respectively.

2. The all-solid-state battery according to claim 1 , wherein the fixing portion is in contact with an end surface of the first current collector layer of the battery unit X and an end surface of the first current collector layer of the battery unit Y.

3. the electrode layer of the battery unit X and the electrode layer of the battery unit Y each include a first active material layer adjacent to a first current collector layer, a solid electrolyte layer, and a second active material layer adjacent to a second current collector layer; The all-solid-state battery according to claim 1 , wherein the fixing portion is in contact with the first active material layer of the battery unit X and the first active material layer of the battery unit Y, respectively.

4. the electrode layer of the battery unit X and the electrode layer of the battery unit Y each include a first active material layer adjacent to a first current collector layer, a solid electrolyte layer, and a second active material layer adjacent to a second current collector layer; The all-solid-state battery according to claim 1 , wherein the fixing portion is in contact with the solid electrolyte layer of the battery unit X and the solid electrolyte layer of the battery unit Y, respectively.

5. The all-solid-state battery according to any one of claims 1 to 4, wherein the fixing portion contains a resin.

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