Electrode body, solid-state battery, and method for manufacturing solid-state battery

Abstract

To provide an electrode body, a solid state battery, and a manufacturing method for the electrode body that are less likely to break when a component exposed on a side is bent.SOLUTION: An electrode body includes a first current collector, a first active material layer, an electrolyte layer, a second active material layer, and a second current collector in this order, and the first current collector includes an extension portion extending from the first active material layer, the electrolyte layer, the second active material layer, and the second current collector, and the extension portion includes a region having a width smaller than the maximum width of the first current collector. A solid state battery and a manufacturing method for the electrode body are also provided.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an electrode assembly, a solid-state battery, and a method for manufacturing a solid-state battery. [Background technology]

[0002] In some electrode bodies, when observed in the thickness direction of the electrode body, in order to electrically connect to external devices, etc., a component for electrically connecting to external devices, etc. is exposed on the side of the electrode body. For example, Patent Document 1 proposes "an electrode for a stacked battery having an electrode current collecting foil, an electrode mixture layer formed on the electrode current collecting foil, and a separator formed on the electrode mixture layer, wherein the electrode has an electrode laminated portion and an electrode terminal portion protruding from the electrode laminated portion, and the electrode mixture layer is exposed when the electrode terminal portion is viewed from the stacking direction of the electrode." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-207746 Summary of the Invention [Problem to be solved by the invention]

[0004] When an electrode assembly having a member exposed on its side surface is housed in a battery, the exposed member may need to be bent, which may cut the exposed member on the side surface when the member is bent, thereby reducing the degree of freedom in the shape of the battery. Therefore, there is a demand for the development of an electrode assembly having a member exposed on the side surface, in which the exposed member has bending resistance.

[0005] The problem that one embodiment of the present disclosure aims to solve is to provide an electrode body in which a component exposed on the side (i.e., an extension portion in an electrode body according to the present disclosure) is less likely to break even when the component is bent. Another embodiment of the present disclosure aims to solve the problem of providing a solid-state battery including an electrode body in which a member exposed on a side surface is less likely to break even when the member is bent. The problem that another embodiment of the present disclosure aims to solve is to provide a manufacturing method for an electrode body that can produce an electrode body in which the exposed member on the side is less likely to break even when the member is bent. [Means for solving the problem]

[0006] The means for solving the above problems include the following means. <1> a first current collector, a first active material layer, an electrolyte layer, a second active material layer, and a second current collector, in this order; the first current collector has an extension portion extending from the first active material layer, the electrolyte layer, the second active material layer, and the second current collector, The electrode assembly wherein the extension portion includes a region having a width smaller than the maximum width of the first current collector. <2> The minimum width of the extension portion is 70% or more and 80% or less of the maximum width of the first current collector. <1> The electrode body according to claim 1. <3> The total Young's modulus of the first active material layer, the electrolyte layer, and the second active material layer is 6 GPa or more. <1> or <2> The electrode body according to claim 1. <4> <1> ~ <3> A solid-state battery comprising the electrode assembly according to any one of the above. <5> a step of laminating a substrate, a first active material layer, an electrolyte layer, and a second active material layer in this order to obtain a laminate having regions in which the substrate extends from the first active material layer, the electrolyte layer, and the second active material layer; cutting off a portion of the extended region of the base material at a position away from a region where the first active material layer, the electrolyte layer, and the second active material layer are stacked; A method for manufacturing an electrode assembly having the above structure. [Effects of the Invention]

[0007] According to one embodiment of the present disclosure, an electrode assembly is provided in which even when a member exposed on a side surface (that is, an extension portion in an electrode assembly according to the present disclosure) is bent, the member is unlikely to break. According to another embodiment of the present disclosure, there is provided a solid-state battery including an electrode assembly in which a member exposed on a side surface is unlikely to be cut even when the member is bent. According to another embodiment of the present disclosure, there is provided a method for manufacturing an electrode assembly that can obtain an electrode assembly in which even when a member exposed on a side surface is bent, the member is less likely to break. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic perspective view showing an example of a layered structure of an electrode body according to the present disclosure. FIG. [Figure 2] 1 is a schematic top view showing an example of a layered structure of an electrode body according to the present disclosure. FIG. [Figure 3] FIG. 2 is a schematic top view illustrating an example of an extension portion according to the present disclosure. [Figure 4] FIG. 2 is a schematic top view illustrating an example of an extension portion according to the present disclosure. [Figure 5] 1 is a schematic perspective view illustrating an electrode assembly and a current collecting terminal according to the present disclosure. FIG. [Figure 6] 1 is a schematic perspective view illustrating a current collector, a current collecting terminal, and a laminate film according to the present disclosure. FIG. [Figure 7] 1 is a schematic side view illustrating an electrode assembly and a current collecting terminal according to the present disclosure. [Figure 8] 1 is a schematic side view illustrating an example of a solid state battery according to the present disclosure. [Figure 9] 1 is a side view of an example of a solid-state battery according to the present disclosure, viewed from the collector terminal side. FIG. [Figure 10] 1 is a plan view of an example of a solid-state battery according to the present disclosure, viewed from the thickness direction of the solid-state battery; [Figure 11] 1 is a plan view of an example of a solid-state battery according to the present disclosure, viewed from the thickness direction of the solid-state battery; [Figure 12] 1 is a schematic side view of a portion of an example of a solid-state battery according to the present disclosure, viewed from the collector terminal side. FIG. [Figure 13] FIG. 1 is a schematic cross-sectional view illustrating a portion of a battery according to the present disclosure. [Figure 14] FIG. 1 is a schematic side view illustrating a portion of a battery according to the present disclosure. [Figure 15] FIG. 10 is a schematic side view illustrating a second coating step according to the present disclosure. [Figure 16] FIG. 10 is a schematic side view illustrating a second coating step according to the present disclosure. [Figure 17] FIG. 10 is a schematic side view illustrating a second coating step according to the present disclosure. [Figure 18] FIG. 1 is a schematic side view illustrating a jig according to the present disclosure. [Figure 19] FIG. 2 is a schematic top view of an electrode body produced in Examples and Reference Examples. [Figure 20] FIG. 10 is a schematic top view of an electrode body produced in a comparative example. [Figure 21] FIG. 1 is a schematic cross-sectional view showing an example of a solid-state battery. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present disclosure will be described. These descriptions and examples are intended to illustrate the embodiment and are not intended to limit the scope of the invention. In the present specification, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range. In addition, in the present specification, the upper or lower limit of a numerical range may be replaced with a value shown in the examples.

[0010] Each component may contain multiple types of the corresponding substance. When referring to the amount of each component in a composition, if there are multiple substances corresponding to each component in the composition, the amount refers to the total amount of those multiple substances present in the composition, unless otherwise specified. The term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes as long as the intended effect of the process is achieved.

[0011] <Electrode body> The electrode body according to the present disclosure has a first current collector, a first active material layer, an electrolyte layer, a second active material layer, and a second current collector, in this order, and the first current collector has an extension portion extending from the first active material layer, the electrolyte layer, the second active material layer, and the second current collector, and the extension portion includes a region having a width smaller than the maximum width of the first current collector. Here, the "width" refers to the length in a direction perpendicular to the extending direction of the extending portion.

[0012] The electrode assembly according to the present disclosure has the above-described configuration, and is an electrode assembly in which the extending portion is less likely to break even when the extending portion is bent. The reason for this is presumed to be as follows.

[0013] In the electrode assembly according to the present disclosure, the first current collector has a first active material layer, an electrolyte layer, a second active material layer, and an extension portion extending from the second current collector, and the extension portion includes a region having a width smaller than the maximum width of the first current collector. The extension portion does not have a layer such as an active material layer or an electrolyte layer on its surface. This maintains the flexibility of the extension portion. Therefore, even when the extension portion is bent, it is less likely to break. The electrode assembly according to the present disclosure will be described in detail below.

[0014] (Layered structure of electrode body) An example of the layered structure of the electrode assembly according to the present disclosure will be described with reference to FIG. FIG. 1 is a schematic perspective view of one embodiment of an electrode assembly according to the present disclosure. The electrode body 810 has, in this order in the thickness direction, a first current collector 81, a first active material layer 82, an electrolyte layer 83, a second active material layer 84, and a second current collector 85. The first current collector 81 has an extension portion 81a extending from the first active material layer 82, the electrolyte layer 83, the second active material layer 84, and the second current collector 85. The extension portion 81a includes a region 81b having a width smaller than the maximum width of the first current collector 81. 2 shows current collector 810 shown in FIG. 1 as viewed from above positive electrode current collector 85. The symbols in FIG. 2 have the same meanings as those in FIG.

[0015] Here, when the first current collector 81 is, for example, a negative electrode current collector, the first active material layer 82 is a negative electrode active material layer, the second active material layer 84 is a positive electrode active material layer, and the second current collector 85 is a positive electrode current collector. On the other hand, when the first current collector 81 is, for example, a positive electrode current collector, the first active material layer 82 is a positive electrode active material layer, the second active material layer 84 is a negative electrode active material layer, and the second current collector 85 is a negative electrode current collector.

[0016] The electrode assembly according to the present disclosure will be described in detail below, but reference numerals may be omitted.

[0017] (First current collector) In the electrode assembly according to the present disclosure, the first current collector has an extension portion extending from the first active material layer, the electrolyte layer, the second active material layer, and the second current collector, and the extension portion includes a region having a width smaller than the maximum width of the first current collector.

[0018] The first current collector is a positive electrode current collector or a negative electrode current collector. Examples of the material for the first current collector include metal and carbon. The first current collector may be made of stainless steel, aluminum, nickel, iron, titanium, carbon, etc., and is preferably made of an aluminum alloy foil or aluminum foil. The aluminum alloy foil and aluminum foil may be produced using powder. The first current collector may be in the form of, for example, a foil or a mesh, with a foil being preferred.

[0019] The thickness of the first current collector is not particularly limited, but from the viewpoint of bending resistance, it is preferably 10 μm or more and 30 μm or less, and more preferably 12 μm or more and 20 μm or less.

[0020] From the viewpoint of bending resistance, the minimum width of the extension portion is preferably 40% to 80% of the maximum width of the first current collector, more preferably 50% to 70%, and even more preferably 55% to 65%.

[0021] From the viewpoint of bending resistance, the maximum width of the extension portion is preferably 40% to 100% of the maximum width of the first current collector, more preferably 50% to 100%, and even more preferably 55% to 100%.

[0022] The minimum width of the extension portion is appropriately selected depending on the application of the electrode body, but for example, when used in a battery for a hybrid vehicle (HEV), it may be 30 mm or more. The maximum width of the extension portion is appropriately selected depending on the application of the electrode body, but for example, when used in a battery for an HEV vehicle, it may be 110 mm or less.

[0023] The maximum length of the extension portion in the extension direction (also referred to as the longitudinal direction) is preferably 40% or more of the maximum length of the first current collector in the longitudinal direction.

[0024] The maximum length in the vertical direction of the first current collector is appropriately selected depending on the application of the electrode body, but for example, when used in a battery for an HEV vehicle, it is 3 mm or more and 15 mm or less. "Vertical" refers to a direction parallel to the extension direction of the extension portion.

[0025] The shape of the extension is not particularly limited, and examples thereof include the shapes shown in FIGS. 1 and 2, and the shapes shown in (a) to (g) in FIGS. 3 and 4 are schematic top views of an electrode assembly according to an embodiment of the present disclosure, viewed from the positive electrode current collector side. The symbols in Fig. 3 and Fig. 4 have the same meanings as those in Fig. 1. From the viewpoint of bending resistance, the shape shown in FIGS. 1 and 2 is preferable.

[0026] (1st active material layer) The current collector according to the present disclosure has a first active material layer laminated on a first current collector. The first active material layer may be a positive electrode active material layer or a negative electrode active material layer.

[0027] The positive electrode active material layer contains at least a positive electrode active material, and may contain a conductive additive, a solid electrolyte, a binder, and other components as needed.

[0028] The positive electrode active material preferably contains a lithium composite oxide. The lithium composite oxide may contain at least one element selected from the group consisting of F, Cl, N, S, Br, and I. The lithium composite oxide may have a crystal structure belonging to at least one space group selected from the space groups R-3m, Immm, and P63-mmc (also referred to as P63mc or P6 / mmc). The lithium composite oxide may have an O2-type structure in which the transition metal, oxygen, and lithium are primarily arranged. Examples of lithium composite oxides having a crystal structure belonging to R-3m include Li x Me y O α X β (Me represents at least one selected from the group consisting of Mn, Co, Ni, Fe, Al, Cu, V, Nb, Mo, Ti, Cr, Zr, Zn, Na, K, Ca, Mg, Pt, Au, Ag, Ru, W, B, Si, and P, and X represents at least one selected from the group consisting of F, Cl, N, S, Br, and I, and satisfy the conditions 0.5≦x≦1.5, 0.5≦y≦1.0, 1≦α<2, and 0<β≦1.) Examples of lithium composite oxides having a crystal structure belonging to Immm include Li x1 M 1 A 1 2(1.5≦x1≦2.3, M 1 contains at least one selected from the group consisting of Ni, Co, Mn, Cu and Fe, and A 1 contains at least oxygen, and A 1 The ratio of oxygen in the oxide is 85 atomic % or more. x1M 1A 1-x2 M 1B x2 O 2-y A 2 y (0 ≦ x2 ≦ 0.5, 0 ≦ y ≦ 0.3, and at least one of x2 and y is not zero, and M 1A represents at least one selected from the group consisting of Ni, Co, Mn, Cu, and Fe, and M 1B represents at least one selected from the group consisting of Al, Mg, Sc, Ti, Cr, V, Zn, Ga, Zr, Mo, Nb, Ta, and W, and A2 represents at least one selected from the group consisting of F, Cl, Br, S, and P.) Examples include composite oxides represented by the following formula. Examples of the lithium composite oxide having a crystal structure belonging to P63 - mmc include, for example, M1 x M2 y O2 (where M1 represents an alkali metal (at least one of Na and K is preferred), M2 represents a transition metal (at least one selected from the group consisting of Mn, Ni, Co, and Fe is preferred), and x + y satisfies 0 < x + y ≦ 2.) Examples include composite oxides represented by the following formula. Examples of the lithium composite oxide having an O2 - type structure include, for example, Li x [Li α (Mn a Co b M c ) 1-α O2 (where 0.5 < x < 1.1, 0.1 < α < 0.33, 0.17 < a < 0.93, 0.03 < b < 0.50, 0.04 < c < 0.33, and M represents at least one selected from the group consisting of Ni, Mg, Ti, Fe, Sn, Zr, Nb, Mo, W, and Bi.) Examples include composite oxides represented by the following formula, and specific examples include Li 0.744 [Li 0.145 Mn 0.625 Co 0.115 Ni 0.115 O2 and the like.

[0029] Examples of conductive additives include carbon materials, metal materials, and conductive polymer materials. Examples of carbon materials include carbon black (e.g., acetylene black, furnace black, ketjen black, etc.), fibrous carbon (e.g., vapor-grown carbon fiber, carbon nanotube, carbon nanofiber, etc.), graphite, and carbon fluoride. Examples of metallic materials include metal powder (e.g., aluminum powder, etc.), conductive whiskers (e.g., zinc oxide, potassium titanate, etc.), and conductive metal oxides (e.g., titanium oxide, etc.). Examples of conductive polymer materials include polyaniline, polypyrrole, and polythiophene. One type of conductive additive may be used alone, or two or more types may be mixed and used.

[0030] The solid electrolyte preferably contains at least one solid electrolyte species selected from the group consisting of sulfide solid electrolytes, oxide solid electrolytes, and halide solid electrolytes. Specific examples of the sulfide solid electrolyte, oxide solid electrolyte, and halide solid electrolyte are the same as those described below.

[0031] Examples of binders include vinyl halide resins, rubbers, and polyolefin resins. Examples of vinyl halide resins include polyvinylidene fluoride (PVdF) and copolymers of polyvinylidene fluoride and hexafluoropropylene (PVdF-HFP). Examples of polyolefin resins include butadiene rubber (BR), acrylate butadiene rubber (ABR), styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), and butyl rubber (isobutylene-isoprene rubber). Examples of polyolefin resins include polyethylene and polypropylene. The binder may be a diene rubber containing a double bond in the main chain, such as a butadiene rubber in which butadiene accounts for 30 mol% or more of the total.

[0032] Examples of other components include oxide solid electrolytes, halide solid electrolytes, thickeners, surfactants, dispersants, wetting agents, antifoaming agents, and solvents.

[0033] The negative electrode active material layer contains at least a negative electrode active material, and may contain at least one of a negative electrode solid electrolyte, a conductive additive, and a binder, as necessary. Examples of the negative electrode active material include Li-based active materials such as metallic lithium, carbon-based active materials such as graphite, oxide-based active materials such as lithium titanate, and Si-based active materials such as elemental silicon. Examples of the conductive additive, negative electrode solid electrolyte, and binder used in the negative electrode active material layer include the same conductive additive, solid electrolyte, and binder as those exemplified in the positive electrode active material layer and the solid electrolyte and binder contained in the solid electrolyte layer.

[0034] (electrolyte layer) The electrode assembly according to the present disclosure has an electrolyte layer laminated on a first active material layer. The electrolyte layer contains at least an electrolyte, such as a solid electrolyte. In the case of a layer containing a solid electrolyte (solid electrolyte layer), the solid electrolyte layer preferably contains one selected from the group consisting of a sulfide solid electrolyte, an oxide solid electrolyte, and a halide solid electrolyte.

[0035] As a sulfide solid electrolyte, it is preferable to contain sulfur (S) as the main component of the anion element, and further, for example, it is preferable to contain Li element, A element, and S element. The A element is at least one selected from the group consisting of P, As, Sb, Si, Ge, Sn, B, Al, Ga, and In. The sulfide solid electrolyte may further contain at least one of O and halogen elements. Examples of the halogen element (X) include F, Cl, Br, I, etc. The composition of the sulfide solid electrolyte is not particularly limited, and examples include xLi2S·(100-x)P2S5 (70≦x≦80), yLiI·zLiBr·(100-y-z)(xLi2S·(1-x)P2S5) (0.7≦x≦0.8, 0≦y≦30, 0≦z≦30). The sulfide solid electrolyte may have a composition represented by the following general formula (1). Li 4-x Ge 1-x P x S4(0<x<1) ··· Formula (1) In formula (1), at least a part of Ge may be substituted by at least one selected from the group consisting of Sb, Si, Sn, B, Al, Ga, In, Ti, Zr, V, and Nb. Also, at least a part of P may be substituted by at least one selected from the group consisting of Sb, Si, Sn, B, Al, Ga, In, Ti, Zr, V, and Nb. A part of Li may be substituted by at least one selected from the group consisting of Na, K, Mg, Ca, and Zn. A part of S may be substituted by a halogen. The halogen is at least one of F, Cl, Br, and I.

[0036] As an oxide solid electrolyte, it is preferable to contain oxygen (O) as the main component of the anion element. For example, it may contain Li, Q element (Q represents at least one of Nb, B, Al, Si, P, Ti, Zr, Mo, W, and S), and O. Examples of the oxide solid electrolyte include garnet-type solid electrolyte, perovskite-type solid electrolyte, NASICON-type solid electrolyte, Li-P-O-based solid electrolyte, Li-B-O-based solid electrolyte, etc. Examples of the garnet-type solid electrolyte include, for example, Li7La3Zr2O 12 、Li 7-x La3(Zr2-x Nb x )O 12 (0 ≦ x ≦ 2), Li5La3Nb2O 12 and the like. Examples of perovskite-type solid electrolytes include (Li, La)TiO3, (Li, La)NbO3, (Li, Sr)(Ta, Zr)O3, etc. Examples of NASICON-type solid electrolytes include Li(Al, Ti)(PO4)3, Li(Al, Ga)(PO4)3, etc. Examples of Li-P-O-based solid electrolytes include Li3PO4, LIPON (a compound in which a part of O in Li3PO4 is substituted with N), and examples of Li-B-O-based solid electrolytes include Li3BO3, a compound in which a part of O in Li3BO3 is substituted with C, etc.

[0037] As the halide solid electrolyte, a solid electrolyte containing Li, M, and X (M represents at least one of Ti, Al, and Y, and X represents F, Cl, or Br) is preferable. Specifically, Li 6-3z Y z X6 (X represents Cl or Br, and z satisfies 0 < z < 2), Li 6-(4-x)b (Ti 1-x Al x ) b F6 (0 < x < 1, 0 < b ≦ 1.5) is preferable. Among Li 6-3z Y z X6, Li3YX6 (X represents Cl or Br) is more preferable in terms of excellent lithium ion conductivity, and further, Li3YCl6 is preferable. Also, Li 6-(4-x)b (Ti 1-x Al x ) b F6 (0 < x < 1, 0 < b ≦ 1.5) is preferably included together with a solid electrolyte such as a sulfide solid electrolyte from the viewpoint of suppressing oxidative decomposition of the sulfide solid electrolyte, etc.

[0038] The solid electrolyte layer may have a single-layer structure or a multilayer structure of two or more layers.

[0039] The solid electrolyte layer may contain a binder, or may not contain a binder. The binder that can be contained in the solid electrolyte layer is the same as the binder described above.

[0040] (Second active material layer) The electrode assembly according to the present disclosure has a second active material layer laminated on the electrolyte layer. The second active material layer may be a positive electrode active material layer or a negative electrode active material layer. The compositions and preferred embodiments of the positive electrode active material layer and the negative electrode active material layer are the same as those of the first active material layer.

[0041] (Second current collector) The electrode assembly according to the present disclosure has a second current collector laminated on the second active material layer. The second current collector is a positive electrode current collector or a negative electrode current collector. The preferred aspects of the material and thickness of the second current collector are the same as those of the first current collector.

[0042] (Total Young's modulus of first active material layer, electrolyte layer and second active material layer) In the electrode body according to the present disclosure, the combined Young's modulus of the first active material layer, electrolyte layer, and second active material layer is preferably 6 GPa or more, more preferably 9 GPa or more and 15 GPa or less, and even more preferably 12 GPa or more and 14 GPa or less.

[0043] From the viewpoint of reducing resistance, it is preferable that the components contained in the first active material layer, the electrolyte layer, and the second active material layer are dense. In this case, it is preferable that the combined Young's modulus of the first active material layer, the electrolyte layer, and the second active material layer is 6 GPa or more. Conventionally, when assembling an electrode body into a battery, it is sometimes necessary to fold the portion having these layers, and in such a case, the rigidity of these layers may cause the metal foil at the folded portion to break. The electrode body according to the present disclosure has an extended portion, and therefore the extended portion is less likely to break even if the combined Young's modulus of the first active material layer, electrolyte layer, and second active material layer is within the above numerical range.

[0044] Measurement procedure for the combined Young's modulus of the first active material layer, electrolyte layer, and second active material layer The combined Young's modulus of the first active material layer, the electrolyte layer, and the second active material layer is measured in accordance with JIS K7171 (2022) by the following specific procedure. The Young's modulus of the first current collector is measured in accordance with JIS K7171 (2022). Then, the Young's modulus is measured in accordance with JIS K7171 (2022) using a laminate in which a first current collector, a first active material layer, an electrolyte layer, and a second active material layer are laminated in this order as the measurement object. Then, the Young's modulus of the first current collector is subtracted from that of the laminate to calculate the total Young's modulus of the first active material layer, electrolyte layer, and second active material layer.

[0045] <Solid battery> A solid state battery according to the present disclosure includes an electrode assembly according to the present disclosure. The solid-state battery includes so-called all-solid-state batteries (in which the content of electrolytic solution as electrolyte is 0% by mass relative to the total amount of electrolyte) that use an inorganic solid electrolyte as the electrolyte. The structure of the solid-state battery of the present disclosure may include a positive electrode current collector, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode current collector in this order, for example, as shown in FIG. 21 . The solid electrolyte layer B in FIG. 21 may have a two-layer structure. FIG. 21 is a schematic cross-sectional view showing an example of a solid-state battery. The solid-state battery shown in FIG. 21 includes a negative electrode including a negative electrode current collector 113 and a negative electrode layer A, a solid electrolyte layer B, a positive electrode including a positive electrode current collector 115 and a positive electrode layer C, and a negative electrode layer A. The negative electrode layer A includes a negative electrode active material 101, a conductive additive 105, a binder 109, and a solid electrolyte 102. The positive electrode layer C includes a positive electrode active material 103, a binder 111, and a solid electrolyte 102.

[0046] When a set of a positive electrode layer, a solid electrolyte layer, and a negative electrode layer is defined as a power generation unit, the solid-state battery may have only one power generation unit or may have two or more power generation units. When the solid-state battery has two or more power generation units, the power generation units may be connected in series or in parallel.

[0047] The solid-state battery may be configured by sealing the end faces (side faces) of the stacked structure of the positive electrode layer / solid electrolyte layer / negative electrode layer with resin. The electrode current collector may have a buffer layer, an elastic layer, or a PTC (Positive Temperature Coefficient) thermistor layer disposed on the surface. The shape of the solid-state battery is not particularly limited, and may be, for example, a coin type, a cylindrical type, a square type, a sheet type, a button type, a flat type, or a laminate type.

[0048] The solid state battery according to the present disclosure is preferably a battery comprising an electrode assembly according to the present disclosure, a current collecting terminal disposed on a side surface of the electrode assembly, and a laminate film covering the electrode assembly. In particular, the solid state battery according to the present disclosure comprises an electrode body according to the present disclosure, a current collecting terminal arranged on a side portion of the electrode body, and a laminate film covering the electrode body, and when the solid state battery is viewed from the side from the current collecting terminal side, it is preferable that the outer edge of the current collecting terminal is located inside the outer edge of the electrode body, the laminate film is arranged so as to cover the surface that constitutes the outer edge of the current collecting terminal and the surface that constitutes the outer edge of the electrode body, and a fused portion where the inner surfaces of the laminate film are fused together is arranged on the current collecting terminal.

[0049] An example of a solid-state battery according to the present disclosure will be illustrated and described below. Fig. 5 is a schematic perspective view illustrating an electrode assembly and current collecting terminals according to the present disclosure. The electrode assembly 10 shown in Fig. 5(a) has a top surface portion 11, a bottom surface portion 12 facing the top surface portion 11, and four side surfaces (a first side surface portion 13, a second side surface portion 14, a third side surface portion 15, and a fourth side surface portion 16) connecting the top surface portion 11 and the bottom surface portion 12. In Fig. 5(b), a first current collecting terminal 20A is disposed on the first side surface portion 13 of the electrode assembly 10, and a second current collecting terminal 20B is disposed on the third side surface portion 15 of the electrode assembly 10. For example, the first current collecting terminal 20A is a positive electrode current collecting terminal, and the second current collecting terminal 20B is a negative electrode current collecting terminal.

[0050] Here, the extension portion included in the electrode body 10 is bent and connected to the first current collector terminal 20A or the second current collector terminal 20B.

[0051] 6A and 6B are schematic perspective views illustrating a current collector, a current collecting terminal, and a laminate film according to the present disclosure. As shown in FIG. 6A, the laminate film 30 is, for example, a single film. As shown in FIGS. 6A and 6B, the laminate film 30 is folded so as to entirely cover the bottom surface 12, the second side surface 14, the top surface 11, and the fourth side surface 16 of the electrode body 10. In FIG. 6B, at least a portion of the first current collecting terminal 20A and at least a portion of the second current collecting terminal 20B are located inside the folded laminate film 30.

[0052] Fig. 7(a) is a schematic side view illustrating an electrode assembly and a current collecting terminal according to the present disclosure, and Fig. 7(b) is a cross-sectional view taken along line AA in Fig. 7(a). As shown in Figs. 7(a) and 7(b), when the electrode assembly 10 and the current collecting terminal 20 are observed from the current collecting terminal 20 side, the outer edge E2 of the current collecting terminal 20 is located inside the outer edge E1 of the electrode assembly 10. In other words, the dimensions of the current collecting terminal 20 are smaller than the dimensions of the electrode assembly 10.

[0053] 7(C) is a schematic side view illustrating an electrode assembly, a current collecting terminal, and a laminate film according to the present disclosure, and FIG. 7(d) is a cross-sectional view taken along the line AA of FIG. 7(C). As shown in FIGS. 7(c) and 7(d), when the electrode assembly 10, the current collecting terminal 20, and the laminate film 30 are observed from the current collecting terminal 20 side, a space S is formed between the laminate film 30 and the current collecting terminal 20. Therefore, when the current collecting terminal 20 is sealed with the laminate film 30, the excess portion of the laminate film 30 may cause wrinkles in the laminate film 30, which may reduce the sealing performance of the battery. In contrast, in the battery according to the present disclosure, as shown in FIG. 8, a fused portion X is disposed on the current collecting terminal 20, where the inner surfaces of the laminate films 30 (the surfaces facing the current collecting terminal 20) are fused together.

[0054] According to the present disclosure, a fused portion is disposed on the current collecting terminal, thereby resulting in a battery in which deterioration of sealing performance is suppressed. As shown in FIG. 7 above, the dimensions of the current collecting terminal may be smaller than the dimensions of the electrode body. By adopting such a dimensional relationship, for example, when multiple batteries are stacked, contact between adjacent current collecting terminals can be prevented. Preventing contact between adjacent current collecting terminals makes the battery less likely to be damaged. Furthermore, if current collecting terminals having such a dimensional relationship are sealed with a laminate film, for example, wrinkles may occur in the laminate film, which may reduce the sealing performance of the battery. In the present disclosure, by disposing a fused portion X, where the inner surfaces of the laminate film are fused together, on the current collecting terminal, a battery in which deterioration of sealing performance is suppressed even when the dimensions of the current collecting terminal are smaller than the dimensions of the electrode body is obtained.

[0055] (electrode body) A solid state battery according to the present disclosure includes an electrode assembly according to the present disclosure. The shape of the electrode body is not particularly limited, but may, for example, as shown in FIG. 5(a), have a top surface portion 11, a bottom surface portion 12 facing the top surface portion 11, and four side surfaces (first side surface portion 13, second side surface portion 14, third side surface portion 15, and fourth side surface portion 16) connecting the top surface portion 11 and the bottom surface portion 12. The top surface portion 11 and the bottom surface portion 12 both correspond to the main surfaces of the electrode body, and the normal direction to the main surfaces can be defined as the thickness direction. The first side surface portion 13 and the third side surface portion 15 are arranged to face each other. Similarly, the second side surface portion 14 and the fourth side surface portion 16 are arranged to face each other.

[0056] The shape of the top surface portion is not particularly limited, and examples thereof include quadrilaterals such as squares, rectangles, rhombuses, trapezoids, parallelograms, etc. The shape of the top surface portion 11 in Fig. 5(a) is rectangular. The shape of the top surface may be a polygon other than a rectangle, or may be a curved shape such as a circle. The shape of the bottom surface is the same as that of the top surface. The shape of the side surface is not particularly limited, but examples thereof include quadrilaterals such as a square, rectangle, rhombus, trapezoid, and parallelogram.

[0057] (Current collector terminal) In the present disclosure, the current collecting terminal is disposed on the side surface of the electrode assembly. Examples of materials for the current collecting terminals include metals such as SUS. The battery according to the present disclosure may include one current collecting terminal for one electrode body, or may include two or more current collecting terminals. In the latter case, for example, as shown in FIG. 5(b), a pair of current collecting terminals 20 (a first current collecting terminal 20A and a second current collecting terminal 20B) may be arranged to face each other with respect to the electrode body 10. Also, in FIG. 5(b), the pair of current collecting terminals 20 are arranged to face each other in the longitudinal direction of the electrode body 10. On the other hand, although not specifically shown, the pair of current collecting terminals may also be arranged to face each other in the lateral direction of the electrode body.

[0058] The shape of the current collecting terminal is not particularly limited, but examples thereof include quadrilaterals such as squares, rectangles, rhombuses, trapezoids, and parallelograms. The shape of the current collecting terminal 20 in FIG. 7(a) is rectangular. In this rectangle, the thickness direction D T The short side extends along the direction parallel to the thickness direction D T The long sides extend in a direction perpendicular to the plane of the collector terminal. The shape of the collector terminal may be a polygon other than a rectangle, or may be a curved shape such as a circle. The collector terminal may also have a corner where two sides (straight sides) intersect.

[0059] When the battery is viewed from the side from the collector terminal side, the outer edge of the collector terminal is located inside the outer edge of the electrode body. For example, as shown in FIG. 7(a), the outer edge E2 of the collector terminal 20 is located inside the outer edge E1 of the electrode body 10. In other words, the outer edge E2 of the collector terminal 20 is encompassed by the outer edge E1 of the electrode body 10 over its entire periphery. Furthermore, the dimensions of the collector terminal 20 are smaller than the dimensions of the electrode body 10.

[0060] For example, in FIG. 7(a), the length (total circumferential length) of the outer edge E1 of the electrode body 10 is L1, and the length (total circumferential length) of the outer edge E2 of the current collecting terminal 20 is L2. The ratio of L2 to L1 (L2 / L1) may be, for example, 0.7 or more and less than 1, or 0.8 or more and 0.95 or less. Also, for example, in FIG. 7(a), T The length of the outer edge E1 is La, and the thickness direction D T The length of the outer edge E2 in the thickness direction D is defined as Lb. The ratio of Lb to La (Lb / La) is, for example, 0.5 or more and less than 1, and may be 0.8 or more and 0.95 or less. T The length of the outer edge E1 in the direction perpendicular to the T The length of the outer edge E2 in the direction perpendicular to Le is defined as Ld. The ratio of Ld to Le (Ld / Lc) is, for example, 0.5 or more and less than 1, and may be 0.8 or more and 0.95 or less. Also, for example, in FIG. 7(a), the length of the gap between the outer edges E1 and E2 is defined as δ. δ is greater than 0 mm, and may be 0.3 mm or more, or 0.5 mm or more. On the other hand, δ is, for example, 1.5 mm or less.

[0061] (laminating film) The laminate film in the present disclosure covers the electrode body and seals the electrode body together with the current collecting terminals. The laminate film according to the present disclosure has at least a structure in which a heat-sealing layer and a metal layer are laminated. The laminate film may also have a heat-sealing layer, a metal layer, and a resin layer in this order along the thickness direction. Examples of materials for the heat-sealing layer include olefin-based resins such as polypropylene (PP) and polyethylene (PE). Examples of materials for the metal layer include aluminum, aluminum alloys, and stainless steel. Examples of materials for the resin layer include polyethylene terephthalate (PET) and nylon. The thickness of the heat-sealing layer is, for example, 40 μm or more and 100 μm or less. The thickness of the metal layer is, for example, 30 μm or more and 60 μm or less. The thickness of the resin layer is, for example, 20 μm or more and 60 μm or less. The thickness of the exterior body is, for example, 80 μm or more and 250 μm or less.

[0062] As shown in FIG. 6, when the electrode body 10 and the current collecting terminal 20 are observed from the current collecting terminal 20 side, the laminate film 30 is arranged so as to cover the surface that forms the outer edge of the current collecting terminal 20 and the surface that forms the outer edge of the electrode body 10. Also, as shown in FIG. 8, a fused portion X where the inner surfaces of the laminate film 30 are fused together is arranged on the current collecting terminal 20. It is preferable that the fused surface in the fused portion X does not have any voids. Also, in FIG. 8, an end contact portion Y where the ends of the laminate film 30 are fused together is arranged. The end contact portion Y may be bent to fit the shape of the current collecting terminal. This is because excess space can be reduced.

[0063] In FIG. 9, when the solid-state battery 100 is viewed from the side of the current collecting terminal 20, the fused portion X is disposed at a corner that constitutes the outer edge E2 of the current collecting terminal 20. Specifically, the corner that constitutes the outer edge E2 of the current collecting terminal 20 coincides with the end t of the fused surface of the fused portion X. Also, as shown in FIG. 9, the width of the fused surface of the fused portion X is w. The width w is, for example, 0.1 mm or more, and may be 0.3 mm or more, or may be 0.6 mm or more. On the other hand, the width w is, for example, 1.2 mm or less.

[0064] As shown in FIGS. 10 and 11 , when the solid-state battery 100 is viewed from above in the thickness direction, the end position of the laminate film 30 on the current collecting terminal 20 side is designated as α, and the position of the laminate film 30 corresponding to the boundary between the current collecting terminal 20 and the electrode assembly 10 is designated as β. The fused portion X in FIGS. 10 and 11 is continuously disposed from the end position α to position β. Furthermore, when the direction in which the current collecting terminal 20 extends from the electrode assembly 30 is designated as D1, the fused portion X is preferably disposed along the direction D1. Furthermore, the fused portion X may be disposed in at least a portion of the region from the end position α to position β in the direction D1. The length of the fused portion X in the direction D1 is, for example, 1 mm or more, or may be 3 mm or more, or may be 5 mm or more.

[0065] 12(a) is a schematic side view of a part of the solid state battery 100 as viewed from the side of the current collecting terminal 20, and FIG. 12(b) is a cross-sectional view taken along the line AA in FIG. 12(a). As shown in FIGS. 12(a) and 12(b), the thickness direction D of the solid state battery 100 is T 12(a) and 12(b), the highest position of the fused portion X is P1, the highest position of the laminate film 30 disposed on the electrode body 10 is P2, and the highest position of the electrode body 10 is P3. T 12(a) and 12(b), the position P1 is lower than the position P2 in the thickness direction D. T In the thickness direction D, the position P1 is lower than the position P3, but may be the same as the position P3 or may be higher than the position P3. T , it may be lower than the position of the top surface of the electrode body 10.

[0066] 12(c) is a schematic side view of a part of the solid-state battery 100 viewed from the side of the current collecting terminal 20, and FIG. 12(d) is a cross-sectional view taken along the line AA in FIG. 12(c). The fused parts X in the above-described FIGS. 12(a) and 12(b) are arranged at the corners of the current collecting terminal 20. On the other hand, as shown in FIGS. 12(c) and 12(d), the fused parts X are arranged at the corners of the sides constituting the outer edge of the current collecting terminal 20 in the thickness direction D. T 12(c) and 12(d) are arranged on the long side (the long side on the top surface side of the electrode body) that forms the outer edge of the current collecting terminal 20. Even when the fused portion X is disposed at such a position, the position P1 is T 12(c) and 12(d), the position P1 is preferably lower than the position P2 in the thickness direction D. T In the thickness direction D, the position P1 is higher than the position P3, but may be the same as the position P3 or may be lower than the position P3. T , it may be lower than the position of the top surface of the electrode body 10.

[0067] As shown in FIG. 13(a), the end position α of the laminate film 30 on the current collecting terminal 20 side may be closer to the electrode body 10 than the end position γ of the current collecting terminal 20 on the opposite side from the electrode body 10. That is, when the battery is viewed in plan from the thickness direction, the laminate film 30 may cover a portion of the current collecting terminal 20. In this case, a portion of the current collecting terminal 20 (a portion not covered by the laminate film 30) is exposed. On the other hand, as shown in FIG. 13(b), the end position α may coincide with the end position γ. That is, when the battery is viewed in plan from the thickness direction, the laminate film 30 may cover the entire current collecting terminal 20.

[0068] 14(a) to 14(d) are schematic side views of a portion of the solid-state battery 100 viewed from the side of the current collecting terminal 20. As shown in FIG. 14(a), the fused portions X are arranged at corners that form the outer edge of the current collecting terminal 20. Although two fused portions X are shown in FIG. 14(a), one fused portion X may be arranged for one current collecting terminal 20, or three or more fused portions X may be arranged for one current collecting terminal 20. In particular, it is preferable that multiple fused portions X are arranged for one current collecting terminal 20. This is because the excess portion of the laminate film 30 can be dispersed and absorbed. Furthermore, the end contact portion Y in FIG. 14(a) is formed by the ends of the laminate film 30 being fused together with their inner surfaces in contact with each other.

[0069] Alternatively, the fused portions X may be disposed at two corners of the short sides. Alternatively, as shown in FIG. 14(b), two fused portions X may be disposed at two corners of one long side constituting the outer edge of the current collecting terminal 20. Alternatively, as shown in FIG. 14(C), four fused portions X may be disposed at four corners constituting the outer edge (rectangle) of the current collecting terminal 20. The end contact portions Y in FIG. 14(C) are formed by contacting the inner surface of one end of the laminate film 30 with the outer surface of the other end. Alternatively, as shown in FIG. 14(d), the fused portions X may be disposed in the middle (non-corner portion) of the side constituting the outer edge of the current collecting terminal 20.

[0070] <Electrode body manufacturing method> The method for manufacturing an electrode assembly according to the present disclosure includes a step of laminating a substrate, a first active material layer, an electrolyte layer, and a second active material layer in this order to obtain a laminate having regions in which the substrate extends from the first active material layer, the electrolyte layer, and the second active material layer (a laminate formation step); and cutting out a portion of the extended region of the base material at a position away from the region where the first active material layer, the electrolyte layer, and the second active material layer are stacked (cutting out step). The method for manufacturing an electrode assembly according to the present disclosure may also include a preparation step prior to the stack formation step.

[0071] (preparation process) The preparation step is a step of preparing a first active material layer, an electrolyte layer, and a second active material layer.

[0072] In the preparation step, a positive electrode active material layer and a negative electrode active material layer are prepared as the first and second active material layers. The positive electrode active material layer is preferably produced, for example, by mixing the components that can be contained in the positive electrode active material layer described above with a solvent to produce a slurry, applying the slurry to a substrate, and drying it. The negative electrode active material layer is preferably produced, for example, by mixing the components that can be contained in the positive electrode active material layer described above with a solvent to produce a slurry, applying the slurry to a substrate, and drying it. The electrolyte layer is preferably produced, for example, by mixing the components that can be contained in the electrolyte layer described above with a solvent to produce a slurry, and then applying the slurry to a substrate and drying it.

[0073] The method for kneading the components contained in the slurry when obtaining the slurry is not particularly limited, and examples thereof include a method of kneading using a kneading device, such as an ultrasonic homogenizer, a shaker, a thin film rotary mixer, a dissolver, a homomixer, a kneader, a roll mill, a sand mill, an attritor, a ball mill, a vibrator mill, or a high-speed impeller mill.

[0074] The solvent is not particularly limited, and may be any known solvent used in the production of solid state batteries. As the material of the substrate, for example, the same materials as those of the first current collector included in the electrode assembly described above can be applied, and the same applies to the preferred embodiments.

[0075] Here, in preparing the first active material layer, it is preferable to have a region where the base material extends from the first active material layer, because this region where the base material extends will be the region where the base material extends in the laminate described below.

[0076] (Laminate formation process) The laminate formation process is a process of laminating a substrate, a first active material layer, an electrolyte layer, and a second active material layer in this order to obtain a laminate having regions in which the substrate extends from the first active material layer, the electrolyte layer, and the second active material layer.

[0077] The laminate forming step may involve pressing the laminate. Examples of pressing methods include roll pressing and cold isostatic pressing (CIP).

[0078] The pressure during pressing is preferably 0.1 ton / cm 2 More preferably, it is 0.5 t / cm 2 More preferably, it is 1 t / cm 2 The pressure during pressing is preferably 10 t / cm 2 More preferably, it is 8 t / cm or less. 2 More preferably, it is 6 t / cm or less. 2 The following is the result.

[0079] (Cutting process) The cutting step is a step of cutting out a part of the extended region of the base material at a position away from the region where the first active material layer, the electrolyte layer, and the second active material layer are stacked. In the cutting step, a part of the region where the base material extends is cut away, and the region where the base material extends in the laminate is made into an extension portion of the electrode assembly. The method for cutting out the extended region of the base material is not particularly limited, and any known cutting method can be used, such as a cutting method using laser irradiation or a cutting method using a metal blade.

[0080] (Trimming process) The method for manufacturing an electrode body according to the present disclosure may include a step of adjusting the shape of the second active material layer (trimming step) as needed. An example of a method for adjusting the shape of the second active material layer is a method using laser irradiation.

[0081] <Solid-state battery manufacturing method> The method for manufacturing a solid state battery according to the present disclosure includes a step of laminating a substrate, a first active material layer, an electrolyte layer, and a second active material layer in this order to obtain a laminate having regions in which the substrate extends from the first active material layer, the electrolyte layer, and the second active material layer (a laminate formation step); The method includes cutting out a part of the extended region of the substrate at a position away from the region where the first active material layer, the electrolyte layer, and the second active material layer are stacked (cutting step).

[0082] The method for producing a solid state battery according to the present disclosure is not particularly limited as long as it includes the laminate forming step and the cutting step. However, after the cutting step, a step of preparing a structure having an electrode body and a current collecting terminal (preparation step); a step of covering the outer edge of the electrode body in the structure with a laminate film (first covering step); It is preferable to further include a step of covering the outer edge of the current collector terminal in the structure with a laminate film (second covering step).

[0083] (Laminate formation process and cutting process) The laminate forming step and cutting step are the same as the laminate forming step and cutting step in the above-described method for manufacturing an electrode assembly according to the present disclosure.

[0084] (preparation process) The preparation step is a step of preparing a structure having an electrode body and a current collecting terminal. The electrode body and current collecting terminals are the same as those described for the solid-state battery, and therefore, a description thereof will be omitted here. In this step, the extending portion of the electrode body is bent and connected to a current collecting terminal.

[0085] (First coating process) The first covering step in the present disclosure is a step of covering the outer edge of the electrode body in the above structure with a laminate film. For example, as shown in FIGS. 6(a) and 6(b), in the first covering step, the surfaces constituting the outer edge of the electrode body 10 (e.g., the bottom surface portion 12, the second side surface portion 14, the top surface portion 11, and the fourth side surface portion 16) are covered with a laminate film 30. At this time, the electrode body 10 and the laminate film 30 may be brought into close contact with each other. Also, as shown in FIG. 6(b), an end overlap portion z where the ends of the laminate film 30 overlap is heated. This forms an end contact portion Y where the ends of the laminate film 30 are fused together. The laminate film may be previously folded to fit the shape of the electrode body.

[0086] 7(c) and 7(d), a space S is usually formed between the laminate film 30 and the current collecting terminal 20. This space S disappears in the second covering step described later, and a fused portion is formed instead.

[0087] (Second coating process) The second covering step in the present disclosure is a step of covering the surface that forms the outer edge of the current collector terminal with the laminate film. Also, in the second covering step, a fused portion is formed.

[0088] In the second covering step, the current collecting terminal and the laminate film are brought into close contact with a jig capable of surface contact with the surface constituting the outer edge of the current collecting terminal. FIG. 15 is a schematic side view illustrating the second covering step in the present disclosure. As shown in FIG. 15(a), a space S is formed between the laminate film 30 and the current collecting terminal 20 by the first covering step described above. Furthermore, an end contact portion Y is formed by the first covering step described above. Next, as shown in FIG. 15(b), jigs 41, 42, 43, and 44 are pressed into the laminate film 30 and the current collecting terminal 20. It is preferable that the jigs 41 to 44 are heated. In the thickness direction D T In this example, the length of the jig 42 (the length in the vertical direction in the drawing) is shorter than the length of the current collecting terminal 20 (the length in the vertical direction in the drawing). Therefore, a gap is formed between the jig 41 and the jig 42, and the excess portion of the laminate film 30 gathers in the gap. As a result, a fused portion X is formed as shown in FIG. 15(c).

[0089] Furthermore, when the shape of the current collecting terminal in side view is rectangular, the second covering step may include a first adhesion treatment and a second adhesion treatment, which will be described later. For example, as shown in FIG. 16(a), the shape of the current collecting terminal 20 in side view is rectangular. This rectangle has a first side s1, a second side s2 adjacent to the first side s1, a third side s3 adjacent to the second side s2 and facing the first side s1, and a fourth side s4 adjacent to the third side s3 and facing the second side s2. In FIG. 16(a), the first side s1 and the third side s3 correspond to the short sides that form the outer edge of the current collecting terminal 20, and the second side s2 and the fourth side s4 correspond to the long sides that form the outer edge of the current collecting terminal 20.

[0090] Next, as shown in Fig. 16(b), a first jig 41 and a third jig 43 are pressed into the collector terminal 20 from the first side s1 and the third side s3, respectively. This causes the laminate film 30 to adhere to the first side s1 and the third side s3, respectively (first adhesion process). In Fig. 16(b), the first jig 41 and the third jig 43 have a first elastic member 51 and a third elastic member 53, respectively. Examples of materials for the elastic members include silicone rubber and fluororubber.

[0091] Next, as shown in Figures 16(C) and (d), a second jig 42 and a fourth jig 44 are pressed into the collector terminal 20 from the second side s2 and the fourth side s4, respectively. This causes the laminate film 30 to adhere to the second side s2 and the fourth side s4, respectively (second adhesion process). At this time, by pressing the second jig 42 and the fourth jig 44, the first elastic member 51 and the third elastic member 53 are compressed and deformed. This forms a fused portion X, as shown in Figure 16(e).

[0092] The circumstances under which the fused portion X is formed will be described with reference to Figure 17. As shown in Figure 17(a), in the first adhesion process, a jig 45 having an elastic member 55 is pressed into the current collecting terminal 20. While maintaining this state, as shown in Figure 17(b), in the second adhesion process, the elastic member 55 is compressively deformed by a jig 46. At this time, since the elastic member 55 is softer than the current collecting terminal 20, the jig 45, and the jig 46, it is preferentially compressed and deformed, and the excess portion of the laminate film 30 is folded in response to this compressive deformation, forming the fused portion X.

[0093] In the present disclosure, it is preferable that the first and third sides correspond to the short sides that form the outer edge of the current collecting terminal 20, and the second and fourth sides correspond to the long sides that form the outer edge of the current collecting terminal 20. In this case, the first and third jigs, which are not heated, may be pressed in during the first adhesion treatment, and the second and fourth jigs, which are heated, may be pressed in during the second adhesion treatment. By heating the entire outer edge of the current collecting terminal 20 only with heat input from the jigs on the long sides (the second and fourth jigs), the structure of the sealing machine can be simplified.

[0094] As shown in FIG. 18(a), in a state where the jig 45 having the elastic member 55 is pressed, T In this case, it is preferable that the position P5 of the apex of the end of the elastic member 55 on the collector terminal 20 side is higher than the position P6 of the apex of the end of the collector terminal 20 on the elastic member 55 side. By satisfying the relationship of position P5 > position P6, the inner surfaces of the laminate film 30 are strongly compressed together, and a fused portion with better sealing properties is formed. That is, TThe length of the elastic member 55 and the jig 45 in the thickness direction D T 18(a), a part of the elastic member 55 is disposed between the jig 45 and the current collecting terminal 20. On the other hand, as shown in FIG. 18(b), the elastic member 55 does not have to be disposed between the jig 45 and the current collecting terminal 20. As shown in FIG. 18(C), a notch 55a may be disposed in the end t5 of the elastic member 55 on the current collecting terminal 20 side. By disposing the notch 55a, the fused portion can be formed stably. [Example]

[0095] Examples will be described below, but the present invention is not limited to these examples. In the following description, unless otherwise specified, all "parts" and "%" are by mass.

[0096] <Preparation of positive electrode active material> Using a rolling fluidized coating device (manufactured by Powrex Corporation), Li was coated in an air atmosphere. 1.15 Ni 1 / 3 Co 1 / 3 Particles with O2 as the main phase were coated with lithium niobate and then fired in an air atmosphere to obtain a positive electrode active material with a lithium niobate coating layer.

[0097] Example 1 [Preparation of electrode body] (preparation process) - Preparation of positive electrode active material layer (second active material layer) - A polypropylene container was charged with 2 parts polyvinylidene fluoride (PVdF) as a binder, 100 parts positive electrode active material, 30 parts sulfide solid electrolyte (Li2S-P2S5-based glass ceramic), 2.5 parts carbon fiber ("VGCF-H" manufactured by Showa Denko K.K.) as a conductive additive, and butyl butyrate as a solvent to a solids content of 65%. The mixture was then stirred for 30 seconds using an ultrasonic disperser (UH-50 manufactured by SMT Corporation). The polypropylene container was then shaken for 3 minutes using a shaker (TTM-1 manufactured by Shibata Scientific Co., Ltd.), stirred for 30 seconds using the ultrasonic disperser, and then shaken for another 3 minutes using the shaker to obtain a slurry. The slurry was then applied to an aluminum foil substrate using a blade method with an applicator. The coating was then air-dried and then dried on a hot plate at 100 °C for 30 minutes to produce a laminate of the substrate and positive electrode active material layer. The amount of the slurry applied to the substrate was adjusted so that the thickness of the positive electrode active material layer would be 15 μm when pressed at 4 t / cm.

[0098] - Preparation of negative electrode active material layer (first active material layer) - In a polypropylene container, 2 parts of polyvinylidene fluoride (PVdF) as a binder and Li4Ti50 as a negative electrode active material are placed. 12 100 parts of the sintered body, 35 parts of a sulfide solid electrolyte (Li2S-P2S5-based glass ceramic), and butyl butyrate as a solvent were added to a solids content of 65%, and the mixture was stirred for 30 seconds using an ultrasonic disperser (UH-50, manufactured by SMT Corporation) to obtain a slurry. The slurry was applied to the surface of the aluminum foil substrate using a blade method with an applicator. A portion of the substrate was left uncoated with the slurry, forming an area where the substrate extended from the negative electrode active material layer. The coating was then air-dried and then dried on a hot plate at 100 °C for 30 minutes to form a negative electrode active material layer on the substrate. Then, a negative electrode active material layer was prepared on the back surface of the aluminum foil substrate in the same manner. At this time, in the area of ​​the surface of the aluminum foil that was not coated with the slurry, the back surface was also not coated with the slurry, so that a part of the substrate was exposed. In this way, a laminate of the substrate and the negative electrode active material layer was obtained.

[0099] -Preparation of electrolyte layer- Heptane was added to a polypropylene container as a solvent to a solids content of 60%, and 2 parts of a butadiene rubber binder and 100 parts of a sulfide solid electrolyte (Li2S-P2S5-based glass ceramic) were added. The polypropylene container was shaken for 30 minutes using a shaker (Shibata Scientific Co., Ltd. TTM-1), stirred for 30 seconds using an ultrasonic disperser (SMT Corporation UH-50), and then shaken for another 3 minutes using a shaker to obtain a slurry. The slurry was then applied to an aluminum foil substrate using a blade method with an applicator. The coating was then air-dried and then dried on a hot plate at 100 °C for 30 minutes to produce a laminate of the substrate and electrolyte layer.

[0100] (Laminate formation process) A laminate of the substrate and the negative electrode active material layer and a laminate of the substrate and the electrolyte layer were attached together so that the negative electrode active material layer and the electrolyte layer were in contact with each other, and pressed at 1.6 t / cm. The substrate in contact with the electrolyte layer was then peeled off. Next, a laminate of the substrate and the positive electrode active material layer was attached together so that the positive electrode active material layer and the electrolyte layer were in contact with each other, and pressed at 1.6 t / cm. The substrate in contact with the positive electrode active material layer was then peeled off. Then, by pressing at 5 t / cm (this pressing is also referred to as "final pressing"), a laminate having a laminate structure of substrate / negative electrode active material layer / electrolyte layer / positive electrode active material layer was obtained. In this laminate, a portion of the substrate in contact with the negative electrode active material layer was exposed.

[0101] (Cutting and trimming processes) The positive electrode active material layer was laser trimmed, and a portion of the region of the laminate where the substrate extended was cut away to produce a negative electrode current collector (first current collector) having an extended portion including a region having a width smaller than the maximum width of the negative electrode current collector, as shown in Fig. 19. The symbols in Fig. 19 are the same as those in Fig. 1.

[0102] (Other processes) Acetylene black and an acrylic binder were weighed and mixed in a volume ratio of 40:60. Ethyl acetate was then added to prepare a carbon coating composition. The carbon coating composition was then applied to an aluminum foil to a thickness of 2 μm and dried at 100°C for 1 hour to prepare a positive electrode current collector (second current collector). The positive electrode current collector was attached to the laminate that had been cut out so that the positive electrode active material layer did not protrude from the laminate, and pressed at 140° C. and 5 MPa to obtain an electrode assembly.

[0103] [Fabrication of solid-state batteries] A solid state battery was obtained by going through the (preparation step), (first covering step) and (second covering step) in the above-mentioned <Method for manufacturing a solid state battery>. The solid-state battery comprises an electrode body, a current collecting terminal arranged on the side of the electrode body, and a laminate film covering the electrode body; when the solid-state battery is viewed from the side from the current collecting terminal side, the outer edge of the current collecting terminal is located inside the outer edge of the electrode body, the laminate film is arranged to cover the surface that constitutes the outer edge of the current collecting terminal and the surface that constitutes the outer edge of the electrode body, and a fused portion where the inner surfaces of the laminate film are fused together is arranged on the current collecting terminal.

[0104] <Example 2> A solid state battery was obtained in the same procedure as in Example 1, except that the final pressing pressure in the (laminate formation step) was changed to 4 t / cm.

[0105] <Comparative Example 1> In the cutting and trimming steps, the positive electrode active material layer was laser trimmed, and the region of the laminate where the substrate was exposed was cut out, as shown in Fig. 20. A solid state battery was obtained in the same procedure as in Example 1, except that the symbols in Fig. 20 are the same as those in Fig. 1.

[0106] <Comparative Example 2> In the (cutting and trimming) steps, the positive electrode active material layer was laser trimmed, and the region of the laminate where the base material extended was cut out, as shown in FIG. 20. A solid state battery was obtained in the same procedure as in Example 2, except that:

[0107] <Reference example> A solid state battery was obtained in the same procedure as in Example 1, except that the final pressing pressure in the laminate formation step was changed to 2 t / cm.

[0108] <Evaluation> (Total Young's modulus of active material layer and electrolyte) The combined Young's modulus of the active material layer and electrolyte of the electrode body obtained in each example was measured according to the procedure described in "Measurement procedure for combined Young's modulus of active material layer and electrolyte layer." The results are shown in Table 1.

[0109] (Evaluation of cuttability of extension part) The confining pressure of the electrode body in the solid state battery obtained in each example was set to 5 MPa, and a vibration test was carried out according to the following procedure. First, vibration was applied in the vertical direction (extension direction of the extension portion) for 15 minutes. The vibration frequency was changed from 7 Hz to 200 Hz, and then from 200 Hz to 7 Hz. Next, vibration was applied in the horizontal direction (direction perpendicular to the extension direction of the extension portion) for 15 minutes. The vibration frequency was changed from 7 Hz to 200 Hz, and then from 200 Hz to 7 Hz. Finally, vibration was applied in the thickness direction of the electrode body for 15 minutes. The vibration frequency was changed from 7 Hz to 200 Hz, and then from 200 Hz to 7 Hz. The above procedure was counted as one set, and a total of 12 sets were performed to conduct the vibration test. The solid-state battery was then disassembled to check whether or not the extension portion had been cut. The results are shown in Table 1. If the extension portion had been cut, it was recorded as "cut," and if the extension portion had not been cut, it was recorded as "not cut."

[0110] [Table 1]

[0111] In Table 1, "Configuration of electrode body" indicates whether the electrode body after (the cutting and trimming steps) corresponds to either FIG. 19 or FIG.

[0112] In the Reference Example, the combined Young's modulus of the first active material layer, electrolyte layer, and second active material layer is low, and therefore the resistance of the solid state battery becomes too high for practical use.

[0113] From the above results, it can be seen that the electrode body of this example is an electrode body in which the extending portions are less likely to break even when the extending portions are bent. [Explanation of symbols]

[0114] 10 Electrode body 11 Top part 12 Bottom part 13 First side part 14 Second side part 15 Third side part 16 4th side part 20 Current collector terminal 30 Laminating Film 100 batteries 81 First current collector 81a Extension 81b: a region having a width smaller than the maximum width of the first current collector 82 First active material layer 83 Electrolyte layer 84 Second active material layer 85 Second current collector 810 Electrode body

Claims

1. a first current collector, a first active material layer, an electrolyte layer, a second active material layer, and a second current collector, in this order; the first current collector has a first extension portion extending from the first active material layer, the electrolyte layer, the second active material layer, and the second current collector, the second current collector has a second extension portion extending from the first current collector, the first active material layer, the electrolyte layer, and the second active material layer to a side opposite to the first extension portion, the first extension portion includes a region having a width smaller than a maximum width of the first current collector, the region is at least 2 mm away from a region where the first active material layer, the electrolyte layer, and the second active material layer are stacked; a minimum width of a region having a width smaller than the maximum width of the first current collector is 40% or more and 80% or less of the maximum width of the first current collector, An electrode body, wherein the maximum width of the first extension portion is 100% of the maximum width of the first current collector.

2. 2. The electrode assembly according to claim 1, wherein the minimum width of the region having a width smaller than the maximum width of the first current collector is 55% or more and 65% or less of the maximum width of the first current collector.

3. 2. The electrode body according to claim 1, wherein the total Young's modulus of the first active material layer, the electrolyte layer, and the second active material layer is 6 GPa or more.

4. A solid state battery comprising the electrode assembly according to any one of claims 1 to 3.

5. A method for manufacturing an electrode assembly according to any one of claims 1 to 3, comprising: a step of stacking a first current collector, a first active material layer, an electrolyte layer, a second active material layer, and a second current collector in this order to obtain a laminate having a region where the first current collector extends from the first active material layer, the electrolyte layer, the second active material layer, and the second current collector, and a region where the second current collector extends from the first current collector, the first active material layer, the electrolyte layer, and the second active material layer; cutting off a portion of the extended region of the first current collector at a position 2 mm or more away from a region where the first active material layer, the electrolyte layer, and the second active material layer are stacked, from the extended region of the first current collector; A method for manufacturing an electrode assembly having the above structure.

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