Battery and method for manufacturing battery

Abstract

To provide a battery and a manufacturing method of the battery capable of improving insertability of an electrode laminate into a battery case and enhancing energy density.SOLUTION: The battery 10A includes a rectangular plate-shaped electrode-stacked body 20 in which positive electrode current collectors, positive electrode active materials, solid electrolytes, negative electrode active materials, and negative electrode current collectors are stacked, and a battery case 40 in which the electrode-stacked body 20 is housed. The battery case 40 includes a case main body 42 that forms a cylindrical housing and has rectangular opening portions 43 on two opposing surfaces, and a terminal member 44 that seals the opening portions 43, and the electrode laminate 20 includes chamfered portions 50 obtained by chamfering at least some corner portions 21A among a plurality of corner portions 21A provided at end portions in the opposing direction of the opening portions 43.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a battery and a method for manufacturing the battery. [Background technology]

[0002] Patent Document 1 discloses a battery in which chamfered portions are provided at the corners of an electrode laminate (battery element), and the chamfered portions are covered with an insulating member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. WO2021 / 230009 Summary of the Invention [Problem to be solved by the invention]

[0004] It is known that a solid-state battery in which the electrolyte layer of the electrode laminate contains a solid electrolyte expands and contracts less during charging and discharging than a battery that uses a liquid electrolyte. Therefore, it is preferable to make the gap between the battery case and the electrode laminate as small as possible when the electrode laminate is housed therein. However, this poses a problem in that it is not easy to prevent interference between the battery case and the electrode laminate during the process of inserting the electrode laminate into the battery case.

[0005] In this regard, it is expected that the above interference can be suppressed by chamfering the corners of the electrode laminate, as in the battery described in Patent Document 1. However, in the technology of Patent Document 1, the entire length of one side of the rectangular parallelepiped electrode laminate is chamfered as a corner, which reduces the energy density of the battery.

[0006] In consideration of the above, an object of the present invention is to provide a battery and a method for manufacturing the battery that can improve the ease of inserting an electrode stack into a battery case and increase the energy density. [Means for solving the problem]

[0007] A battery according to a first aspect of the present invention is a battery comprising: a rectangular plate-shaped electrode stack in which a positive electrode current collector, a positive electrode active material, a solid electrolyte, a negative electrode active material, and a negative electrode current collector are stacked; and a battery case in which the electrode stack is housed. The battery case is a cylindrical housing and comprises a case body having rectangular openings on two opposing sides, and a lid that seals the openings. The electrode stack has chamfered portions in which at least some of a plurality of corners provided at the end opposite the openings are chamfered.

[0008] In the battery according to the first aspect, the battery includes a rectangular plate-shaped electrode stack in which a positive electrode current collector, a positive electrode active material, a solid electrolyte, a negative electrode active material, and a negative electrode current collector are stacked, and is a so-called solid-state battery. The battery case that houses this electrode stack includes a case body and a lid that form a housing, and the lid seals rectangular openings provided on two opposing sides of the case body. Therefore, the rectangular plate-shaped electrode stack passes through the rectangular openings of the case body and is housed inside the battery case.

[0009] Here, the electrode stack has chamfered portions in which at least some of the corners of a plurality of corners provided at the end facing the opening are chamfered, which reduces interference between the opening of the case body and the corners of the electrode stack when the electrode stack is placed in the battery case, thereby improving the ease of insertion of the electrode stack into the battery case.

[0010] Furthermore, since the chamfered portion is a corner provided at the end of the electrode stack corresponding to the position of the opening of the case body, the volume removed is smaller than when the entire length of one side of the electrode stack is chamfered as a corner, which allows for an increase in the energy density of the battery.

[0011] A battery according to a second aspect of the present invention has the configuration according to the first aspect, wherein the chamfered portion has a chamfered surface that is a triangular flat surface.

[0012] In the battery according to the second aspect, the chamfered surface of the chamfered portion is formed by a triangular flat surface, and therefore the chamfered portion can be formed by cutting the corner of the electrode laminate along a predetermined planar direction, which makes processing easier than, for example, a configuration in which the chamfered surface is an R-shaped curved surface, and reduces manufacturing costs.

[0013] A battery according to a third aspect of the present invention has the configuration described in the first or second aspect, and a heat-conducting member is arranged inside the battery case between the end where the chamfered portion is provided and the inner surface of the battery case.

[0014] In the battery according to the third aspect, a thermally conductive member is disposed between the end of the electrode stack where the chamfered portion is provided and the inner surface of the battery case, which prevents an air gap from being formed between the chamfered portion and the inner surface of the battery case, thereby improving the heat dissipation performance of the battery.

[0015] A fourth aspect of the present invention relates to a battery having the configuration described in the third aspect, wherein the electrode stack has a larger number of positive electrode current collectors than negative electrode current collectors, and the chamfered portion is provided at a corner of the end of the electrode stack on the negative electrode side.

[0016] In the battery according to the fourth aspect, the electrode laminate has a greater number of positive current collectors than negative current collectors, which puts the negative current collectors at a disadvantage in terms of dissipating heat generated by current flow compared to the positive current collectors. Therefore, by providing a chamfered portion at the corner of the negative electrode-side end of the electrode laminate, the heat dissipation performance near the negative current collector is improved by providing a sufficient amount of thermally conductive material. This improves the heat dissipation performance of the battery in areas where the temperature is likely to increase during heat generation.

[0017] A battery according to a fifth aspect of the present invention has the configuration according to the fourth aspect, wherein the chamfered portion is not provided at the corner of the positive electrode side end portion of the electrode laminate.

[0018] In the battery according to the fifth aspect, the corners of the end of the negative electrode laminate are chamfered to allow sufficient placement of the thermally conductive member, while the corners of the end of the positive electrode laminate are not chamfered. This makes it possible to efficiently improve the heat dissipation performance of the battery in the areas where the temperature is likely to increase during heat generation, while minimizing the volume eliminated by the chamfering, and efficiently increase the energy density of the battery.

[0019] A battery manufacturing method according to a sixth aspect of the present invention is the battery manufacturing method according to the first aspect, and includes the steps of chamfering at least some of the corners of the electrode laminate at the end of the electrode laminate facing the opening, and inserting the electrode laminate into the case body, wherein the end with the chamfered corners is inserted into the opening of the case body.

[0020] In a battery manufacturing method according to a sixth aspect, at least some of the corners of the electrode stack at the end facing the opening are chamfered, and the electrode stack is inserted into the case body. By inserting the end of the electrode stack with the chamfered corners into the opening of the case body during this insertion step, interference between the opening of the case body and the corners of the electrode stack is suppressed, and the electrode stack can be easily inserted into the battery case. Furthermore, this method can produce a battery with an increased energy density. [Effects of the Invention]

[0021] As described above, the battery and the method for manufacturing the battery according to the present invention can improve the insertability of the electrode stack into the battery case and increase the energy density. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a perspective view of a battery according to an embodiment of the present invention. [Figure 2] 2 is a cross-sectional view of the battery case taken along line 2-2 of FIG. 1. FIG. [Figure 3]3 is a cross-sectional view of the battery case taken along line 3-3 in FIG. 2. FIG. [Figure 4] 4 is a cross-sectional view of the electrode stack taken along line 4-4 of FIG. 2.

[0023] FIG. [Figure 5] FIG. 2 is a perspective view schematically illustrating an end portion of an electrode stack according to the present embodiment and a chamfered portion provided at the end portion. [Figure 6] 1A and 1B are schematic diagrams illustrating a method for manufacturing a battery according to this embodiment, in which (A) shows a process for chamfering the corners of an electrode laminate, (B) shows a process for inserting the electrode laminate into a case body of a battery case, (C) shows a process for joining the electrode laminate to an internal terminal, and (D) shows a process for joining the case body of the battery case to a terminal wall portion. DETAILED DESCRIPTION OF THE INVENTION

[0023] The battery 10A according to this embodiment will be described below with reference to FIGS. 1 to 6. Note that the arrow W1 shown in each drawing indicates a first direction, the arrow W2 indicates a second direction, and the arrow W3 indicates a third direction. The first, second, and third directions are perpendicular to each other. In this embodiment, the first direction W1 coincides with the width direction of the battery 10A. The second direction W2 coincides with the thickness direction of the battery 10A. The third direction W3 coincides with the height direction of the battery 10A.

[0024] Unless otherwise specified in the specification, each element is not limited to one and may be present in multiple numbers. Furthermore, in the drawings, substantially identical elements are given the same reference numerals, and duplicated explanations in the specification are omitted. Furthermore, in the drawings, substantially identical elements are given the same reference numerals, and duplicated explanations in the specification are omitted.

[0025] Furthermore, in this specification, the term "process" includes not only a process that is independent of other processes, but also a process that cannot be clearly distinguished from other processes as long as the purpose of the process is achieved.

[0026] (battery) Fig. 1 is a perspective view of a battery 10A according to this embodiment. Fig. 2 is a cross-sectional view of a battery case 40, schematically showing a state cut along line 2-2 in Fig. 1. Fig. 3 is a cross-sectional view of the battery case, schematically showing a state cut along line 3-3 in Fig. 2. As shown in Figs. 1 to 3, the battery 10A is configured to include an electrode stack 20 constituting a positive electrode and a negative electrode, and a battery case 40 that houses the electrode stack 20.

[0027] (battery case) The battery case 40 includes a case body 42 that forms a cylindrical housing, and a terminal wall portion 44 that serves as a lid. The terminal wall portion 44 seals two openings of the case body 42. The case body 42 and the pair of terminal wall portions 44 are formed from a metal plate such as aluminum or iron.

[0028] The case body 42 has a pair of short-side sidewalls 421 facing in the third direction W3 and a pair of long-side sidewalls 422 facing in the second direction W2, and the pair of short-side sidewalls 421 and the pair of long-side sidewalls 422 form a rectangular opening 43. The rectangular opening 43 constitutes two sides of the case body 42 facing in the first direction W1.

[0029] The pair of short-side side walls 421 form the top and bottom surfaces of the battery case 40, and extend with the first direction W1 as the longitudinal direction and the second direction W2 as the lateral direction. Thus, they form the two short sides of the opening 43 of the case body 42.

[0030] The pair of long-side side walls 422 constitute both side surfaces (front and back) in the thickness direction of the battery case 40, and extend with the first direction W1 as the longitudinal direction and the third direction W3 as the lateral direction. Therefore, they constitute the two long sides of the opening 43 of the case body 42.

[0031] The case body 42 may be formed, for example, by extrusion molding of aluminum material or the like, or may be formed by bending a flat plate using a press and welding the ends of the flat plate together to form a cylindrical housing.

[0032] In this embodiment, the inner surfaces of the short-side sidewall portion 421 and the long-side sidewall portion 422 that face the electrode stack 20 are configured as flat surfaces.

[0033] A positive electrode terminal 26 and a negative electrode terminal 28 are respectively arranged on the pair of terminal wall portions 44. Each terminal wall portion 44 is formed in the shape of a rectangular plate with the plate thickness direction aligned in the first direction W1, and has through holes (reference numerals omitted) through which a positive electrode side external terminal 26B and a negative electrode side external terminal 28B, which will be described later, are inserted.

[0034] The positive electrode terminal 26 includes a positive electrode side internal terminal 26A disposed inside the battery case 40, and a positive electrode side external terminal 26B disposed outside the battery case 40. The positive electrode side internal terminal 26A is formed in the shape of a rectangular plate with its plate thickness direction aligned in the first direction W1, and is disposed along the inner surface of the terminal wall portion 44. The positive electrode side internal terminal 26A is electrically connected to the positive electrode current collector tab 22 of the electrode stack 20. The positive electrode side internal terminal 26A also has a through-hole (reference numeral omitted) through which the positive electrode side external terminal 26B is inserted.

[0035] The positive external terminal 26B is formed, for example, by a metal rivet. The positive external terminal 26B is inserted into the through-holes of the terminal wall 44 and the positive internal terminal 26A, and is fixed by deforming the end portion in the axial direction. In other words, the positive external terminal 26B is fixed to the terminal wall 44 and the positive internal terminal 26A by crimping.

[0036] Furthermore, an insulating member 34 is interposed between the terminal wall portion 44 of the battery case 40 and the positive electrode terminal 26 to electrically insulate the battery case 40 from the positive electrode terminal 26 .

[0037] The negative electrode terminal 28 includes a negative electrode internal terminal 28A disposed inside the battery case 40, and a negative electrode external terminal 28B disposed outside the battery case 40. The negative electrode internal terminal 28A is electrically connected to the negative electrode current collector tab 23 of the electrode stack 20. The configuration of this negative electrode terminal 28 is the same as the configuration of the positive electrode terminal 26, and therefore a detailed description thereof will be omitted.

[0038] (electrode laminate) FIG. 4 is a cross-sectional view of the electrode stack 20, schematically showing a state cut along line 4-4 in FIG. 2. As shown in FIGS. 2 and 4, the electrode stack 20 is formed in the shape of a rectangular plate as a whole. The electrode stack 20 has an electrode body 21, a plurality of positive electrode current collector tabs 22, and a plurality of negative electrode current collector tabs 23. The electrode body 21 includes a plurality of unit electrode bodies 21U. The plurality of unit electrode bodies 21U are stacked along the second direction W2. The plurality of unit electrode bodies 21U are electrically connected in parallel.

[0039] The electrode body 21 is formed, for example, in the shape of a rectangular parallelepiped (rectangular plate) with the first direction W1 as its width direction and the second direction W2 as its thickness direction. A plurality of positive electrode current collecting tabs 22 are provided to protrude from one side of the electrode body 21 in the first direction W1. A plurality of negative electrode current collecting tabs 23 are provided to protrude from the other side of the electrode body 21 in the first direction W1.

[0040] The unit electrode body 21U has a monopolar laminate structure. Specifically, the unit electrode body 21U has two solid electrolyte layers 211, two positive electrode active material layers 212, two negative electrode active material layers 213, two positive electrode current collectors 214, and one negative electrode current collector 215. The positive electrode current collector 214, the positive electrode active material layer 212, the solid electrolyte layer 211, the negative electrode active material layer 213, the negative electrode current collector 215, the negative electrode active material layer 213, the solid electrolyte layer 211, the positive electrode active material layer 212, and the positive electrode current collector 214 are laminated in this order along the second direction W2.

[0041] One positive electrode current collector tab 22 is connected to one positive electrode current collector 214. One negative electrode current collector tab 23 is connected to one negative electrode current collector 215. The number of positive electrode current collector tabs 22 in the electrode stack 20 is greater than the number of negative electrode current collector tabs 23 in the electrode stack 20.

[0042] The solid electrolyte layer 211 includes a solid electrolyte. The solid electrolyte is not particularly limited and may be an aggregate of a plurality of particles. The solid electrolyte preferably includes one selected from the group consisting of a sulfide solid electrolyte, an oxide solid electrolyte, and a halide solid electrolyte. The solid electrolyte may be a known solid electrolyte.

[0043] The solid electrolyte layer may further include a binder. The binder may be used for bonding between solid electrolytes. The binder may be used for bonding between the solid electrolyte and the positive electrode active material layer 112 or the negative electrode active material layer 113. Examples of the binder include a vinyl halide resin (e.g., polyvinylidene fluoride (PVdF)), rubbers (e.g., acrylate butadiene rubber (ABR), styrene-butadiene rubber (SBR), etc.), and a polyolefin resin (e.g., polyethylene (PE), polypropylene (PP), etc.).

[0044] The positive electrode active material layer 212 contains a positive electrode active material. The positive electrode active material layer 212 may contain at least one of a positive electrode solid electrolyte, a conductive additive, and a binder, as necessary.

[0045] 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. The lithium composite oxide may have an O2-type structure in which the transition metal, oxygen, and lithium are primarily arranged. The positive electrode active material may be a known positive electrode active material.

[0046] Examples of the solid electrolyte for the positive electrode include the same solid electrolytes as those exemplified as the solid electrolyte contained in the solid electrolyte layer.

[0047] Examples of conductive additives include carbon materials (e.g., carbon black, carbon nanotubes, graphite, or carbon fluoride), metal materials (e.g., aluminum powder or conductive whiskers), or conductive polymer materials (e.g., polyaniline, polypyrrole, or polythiophene).

[0048] Examples of the binder include the same binders as those exemplified as the binder contained in the solid electrolyte layer.

[0049] The negative electrode active material layer 213 contains a negative electrode active material. The negative electrode active material layer 213 may contain at least one of a negative electrode solid electrolyte, a conductive additive, and a binder, as necessary.

[0050] Examples of the negative electrode active material include a Li-based active material (e.g., metallic lithium), a carbon-based active material (e.g., graphite), an oxide-based active material (e.g., lithium titanate), or a Si-based active material (e.g., elemental Si).

[0051] Examples of the solid electrolyte for the negative electrode include the same solid electrolytes as those exemplified as the solid electrolyte for the positive electrode that can be used in the positive electrode active material layer.

[0052] Examples of the conductive additive that can be used in the negative electrode active material layer include the same ones as those exemplified as the conductive additive that can be used in the positive electrode active material layer.

[0053] Examples of binders that can be used in the negative electrode active material layer include the same binders as those exemplified as binders that can be used in the positive electrode active material layer.

[0054] The positive electrode current collector 214 collects current from the positive electrode active material layer 212. The material of the positive electrode current collector is not particularly limited, and examples thereof include stainless steel, aluminum, copper, nickel, iron, titanium, and carbon. The positive electrode current collector may be an aluminum alloy foil or an aluminum foil. The aluminum alloy foil and the aluminum foil may be manufactured using powder. The positive electrode current collector may have a foil or mesh shape, for example. The positive electrode current collector may have a buffer layer, an elastic layer, or a PTC (Positive Temperature Coefficient) thermistor layer disposed on its surface.

[0055] The negative electrode current collector 215 collects current from the negative electrode active material layer 213. The material of the negative electrode current collector is not particularly limited, and examples thereof include stainless steel, aluminum, copper, nickel, iron, titanium, and carbon. The negative electrode current collector may be a copper foil. The negative electrode current collector may have a foil or mesh shape, for example. The negative electrode current collector may have a buffer layer, an elastic layer, or a PTC (Positive Temperature Coefficient) thermistor layer disposed on its surface.

[0056] The positive electrode current collector tab 22 electrically connects the positive electrode current collector 214 and the positive electrode terminal 26. The positive electrode current collector tab 22 is connected to the positive electrode current collector 214. The positive electrode current collector tab 22 protrudes toward one side in the width direction (first direction W1) of the electrode body 21. Specifically, a bundle including a plurality of positive electrode current collector tabs 22 is electrically connected to the positive electrode terminal 26. The positive electrode current collector tab 22 is preferably formed continuously from the positive electrode current collector 214. The material of the positive electrode current collector tab is not particularly limited and may be a metal (for example, aluminum, stainless steel (SUS), nickel, etc.).

[0057] The negative electrode current collector tab 23 electrically connects the negative electrode current collector 215 and the negative electrode terminal 28. The negative electrode current collector tab 23 is connected to the negative electrode current collector 215. The negative electrode current collector tab 23 protrudes toward the other side of the width direction (first direction W1) of the electrode body 21. Specifically, a bundle including a plurality of negative electrode current collector tabs 23 is electrically connected to the negative electrode terminal 28. The negative electrode current collector tab 23 is preferably formed continuously from the positive electrode current collector 214. The material of the negative electrode current collector tab is not particularly limited and may be a metal (for example, aluminum, stainless steel (SUS), nickel, etc.).

[0058] The electrode stack 20 having the above configuration is placed inside a battery case 40 (see FIG. 3) with a pair of resin sheets 30 as insulating members arranged on both side surfaces in the second direction W2.

[0059] The material of the resin sheet includes known resins (thermoplastic resins, thermosetting resins, etc.) The thermoplastic resins may be elastomers. The resin sheet may further contain a thermally conductive filler as needed. The material of the thermally conductive filler is not particularly limited, and examples thereof include metal oxides (e.g., alumina, silica, magnesia, etc.), metal nitrides (e.g., aluminum nitride, silicon nitride, boron nitride, etc.), artificial diamond, and silicon carbide. The resin sheet may further contain compounding agents as needed, such as fillers such as glass fiber, carbon fiber, and inorganic powder, heat stabilizers, antioxidants, pigments, weathering agents, flame retardants, plasticizers, dispersants, lubricants, release agents, and antistatic agents.

[0060] Furthermore, the electrode stack 20 having the above configuration has a pair of resin fillers 32 disposed on both side surfaces in the third direction W3 as heat conduction members (see FIGS. 2 and 3).

[0061] The material of the resin filler 32 can be the same as the material exemplified for the resin sheet 30. The material of the resin filler may be the same as or different from the material of the resin sheet. As the content of the thermally conductive filler increases, the thermal conductivity tends to improve and the electrical insulation tends to decrease. The thermal conductivity of the resin filler 32 may be higher than that of the resin sheet 30, and the electrical insulation of the resin filler 32 may be lower than that of the resin sheet 30.

[0062] In this embodiment, the resin filler 32 is made of a resin containing a thermally conductive filler, and has high thermal conductivity. For example, the thermal conductivity of the resin filler 32 is set to be higher than that of the air layer.

[0063] The resin sheet 30 and the resin filler 32 are disposed between the battery case 40 and the electrode stack 20 with the electrode stack 20 housed inside the battery case 40. The resin sheet 30 and the resin filler 32 electrically insulate the battery case 40 and the electrode stack 20.

[0064] (chamfered part) Here, the chamfered portion 50, which is a main part of the present invention, will be described. Fig. 5 is a perspective view of the other end portion of the electrode stack 20, and schematically shows the chamfered portion 50 obtained by chamfering the corner portion 21A provided at that end portion.

[0065] The chamfered portions 50 are formed at the end portions in the first direction W1 of the electrode stack 20. More specifically, the chamfered portions 50 are provided at at least some of the corners 21A among the multiple corners 21A provided at the end portions in the first direction W1 of the rectangular parallelepiped-shaped electrode main body 21. The first direction W1 coincides with the opposing direction of the two openings 43 of the case main body 42.

[0066] In the present embodiment, as an example, the chamfered portion 50 is formed at the other end of the electrode body 21 in the first direction W1, i.e., at the end on the negative electrode side where the negative electrode current collector 215 is disposed. In addition, the chamfered portion 50 is not provided at the corner 21A of the end on the positive electrode side (i.e., one end in the first direction W1) of the electrode body 21 (see FIGS. 1 and 2).

[0067] It is not essential that the chamfered portion 50 is not provided at the end on the positive electrode side. It may be provided at one end of the electrode body 21 in the first direction W1, i.e., at the end on the positive electrode side where the positive electrode current collector 214 is disposed.

[0068] 5, four corners 21A are provided at the end of the negative electrode side of the electrode body 21. The number of chamfered portions 50 is not particularly limited, and may be provided at some or all of the four corners 21A. In this embodiment, all corners 21A are chamfered, and four chamfered portions 50 are provided.

[0069] As an example, the chamfered portion 50 is formed by cutting the corner 21A of the electrode body 21 along a predetermined planar direction. Therefore, the chamfered surface 50S of the chamfered portion 50 is a triangular flat surface.

[0070] The shape of the chamfered surface 50S is not particularly limited, and may be, for example, an R-shaped curved surface.

[0071] As shown in FIG. 2, when the electrode stack 20 having the above configuration is housed in a battery case 40, a resin filler (thermal conductive member) is disposed inside the battery case 40 between the end (corner 21A) of the electrode main body 21 where the chamfered portion 50 is provided and the inner surface of the battery case 40. The resin filler 32 is, for example, filled between the end (corner 21A) of the electrode main body 21 and the inner surface of the battery case 40, and is in contact with the chamfered surface 50S of the electrode main body 21 and the inner surface of the battery case 40. Therefore, with respect to the thickness of the resin filler 32 in the third direction W3, the thickness T3 of the other end in the first direction W1 is thicker than the thickness T1 of the central portion in the first direction W1. Furthermore, the thickness T2 of the other end in the first direction W1 is thicker than the thickness T2 of one side in the first direction W1. Therefore, inside the battery case 40, the heat dissipation effect of the resin filler 32 is enhanced at the end in the other first direction.

[0072] Furthermore, at the other end in the first direction W1 inside the battery case 40, the surface area of ​​the electrode body 21 is increased by the chamfered portion 50, so the contact area between the resin filler 32 and the electrode body 21 is larger than at other corners 21A that do not have the chamfered portion 50. This also improves the heat dissipation effect of the resin filler 32.

[0073] [Battery manufacturing method] A method for manufacturing a battery according to this embodiment will be described below with reference to Figures 6(A) to 6(D). The method for manufacturing a battery according to this embodiment is, for example, a method for manufacturing a battery 10A. The method for manufacturing a battery includes a preparation step (chamfering step), an insertion step, a resin filling step, a terminal connection step, and a sealing step.

[0074] (preparation process) In the preparation step, a positive electrode current collector sheet, a positive electrode active material layer sheet, a solid electrolyte layer sheet, a negative electrode active material layer sheet, a negative electrode current collector sheet, a negative electrode active material layer sheet, a solid electrolyte layer sheet, a positive electrode active material layer sheet, and a positive electrode current collector sheet are stacked in this order to form a unit electrode body 11U. Then, a step is performed in which a positive electrode current collector tab 12 is connected to the positive electrode current collector 114 of the unit electrode body 11U, and a negative electrode current collector tab 13 is connected to the negative electrode current collector 115 of the unit electrode body 11U. Next, a step is carried out in which a plurality of unit electrode bodies with current collecting tabs are stacked to obtain an electrode stack 20. The entire opposing surfaces of the plurality of unit electrode bodies are bonded together with an adhesive or the like, so that the electrode stack 20 is formed in the shape of a substantially rectangular plate.

[0075] Next, in the preparation step, a chamfering step is carried out. As shown in FIG. 6(A), the chamfering step is a step of forming chamfered portions 50 by chamfering a plurality of corners 21A provided at the end of the electrode stack 20 in the first direction W1. The method for chamfering the corners 21A is not particularly limited, and any known method may be used.

[0076] Next, a step is performed in which a pair of resin sheets 30 are attached to both side surfaces in the second direction W2 of the electrode stack 20. The method for attaching the resin sheets 30 is not particularly limited, and any known method may be used. After the pair of resin sheets 30 are attached to the electrode stack 20, the chamfering step may be carried out.

[0077] (Insertion process) 5(B), the insertion step is a step of inserting the electrode stack 20 through the opening 43 of the case body 42. In this step, the electrode stack 20 is inserted into the case body 42 from the end on the negative electrode side (the other end in the first direction) first. A chamfered portion 50 is formed at the end on the negative electrode side of the electrode stack 20, thereby suppressing interference between the opening 43 of the case body 42 and the electrode stack 20.

[0078] (Resin filling process) The resin filling step is a step of filling the gap between the short-side sidewall portion 421 of the case body 42 and the electrode stack 20 with unsolidified resin filler 32 to form the resin filler 32. The method of filling the resin filler 32 is not particularly limited and may be any known method. The method of solidifying the unsolidified resin filler 32 is selected appropriately depending on the type of resin.

[0079] (Terminal connection process) The terminal connection step is a step of connecting the multiple positive electrode current collector tabs 22 to the positive electrode terminal 26, and connecting the multiple negative electrode current collector tabs 23 to the negative electrode terminal 28 (FIG. 5(C)). Specifically, the positive electrode current collector tabs 22 are connected to the positive electrode side internal terminal 26A, and the negative electrode current collector tabs 23 are connected to the negative electrode side internal terminal 28A. The connection method is not particularly limited and may be any known method. In this embodiment, the connections are made by welding. In this step, the positive external terminal 26B and the negative external terminal 28B are respectively attached to the insulating member 34.

[0080] (Sealing process) The sealing step is a step of attaching a pair of terminal walls 44 to the opening 43 of the case body 42 to seal the opening 43 of the case body 42 (FIG. 5(D)). The sealing method is not particularly limited and may be any known method. In this embodiment, the connection is made by welding.

[0081] (Action and effect) As described above, the battery 10A according to this embodiment includes a rectangular plate-shaped electrode stack 20 in which a positive electrode current collector 214, a positive electrode active material layer 212, a solid electrolyte layer 211, a negative electrode active material layer 213, and a negative electrode current collector 215 are stacked, and is a so-called solid-state battery. The battery case 40 that houses the electrode stack 20 includes a case body 42 and a terminal wall portion 44 (lid) that form a housing, and the terminal wall portion 44 seals rectangular openings 43 provided on two opposing surfaces of the case body 42. Therefore, the rectangular plate-shaped electrode stack 20 passes through the rectangular openings 43 of the case body 42 and is housed inside the battery case 40.

[0082] Here, the electrode stack 20 has chamfered portions 50 obtained by chamfering at least some of the corners 21A among a plurality of corners 21A provided at the end of the electrode body 21 in the first direction W1 (the end facing the opening 43). Therefore, when the electrode stack 20 is accommodated in the battery case 40, interference between the opening 43 of the case body 42 and the corners 21A of the electrode stack 20 is suppressed, and the electrode stack 20 can be easily inserted into the battery case 40.

[0083] Furthermore, because the chamfered portion 50 is formed by chamfering the corner 21A provided at the end of the electrode stack 20 corresponding to the position of the opening 43 of the case body 42, the volume removed is smaller than when the entire length of one side of the electrode stack is chamfered as a corner, thereby increasing the energy density of the battery 10A.

[0084] Furthermore, in this embodiment, the chamfered surface 50S of the chamfered portion 50 is configured as a triangular flat surface, and therefore the chamfered portion 50 can be formed by cutting the corner 21A of the electrode body 21 along a predetermined planar direction. This makes processing easier than, for example, a configuration in which the chamfered surface is an R-shaped curved surface, and allows for reduction in manufacturing costs.

[0085] Furthermore, in this embodiment, a resin filler 32 serving as a thermally conductive member is disposed between the end of the electrode body 21 where the chamfered portion 50 is provided and the inner surface of the battery case 40. This prevents an air layer from being formed between the chamfered portion 50 and the inner surface of the battery case 40, thereby improving the heat dissipation performance of the battery 10A.

[0086] Furthermore, in this embodiment, the electrode laminate 20 has a larger number of positive electrode current collectors 214 than negative electrode current collectors 215, and therefore the negative electrode current collectors 215 are at a disadvantage compared to the positive electrode current collectors 214 in terms of dissipating heat generated by current flow. For this reason, by providing the chamfered portion 50 at the corner 21A at the end on the negative electrode side of the electrode laminate 20, the heat dissipation performance near the negative electrode current collector 215 is improved by sufficient arrangement of the resin filler 32. This makes it possible to improve the heat dissipation performance of the battery 10A in areas where the temperature is likely to increase during heat generation.

[0087] Furthermore, in this embodiment, a chamfered portion 50 is provided at the corner 21A at the end of the electrode body 21 on the negative electrode side, and a resin filler 32 is disposed therein, while a chamfered portion 50 is not provided at the corner 21A at the end on the positive electrode side. This makes it possible to efficiently improve the heat dissipation performance of the parts of the battery 10A that are likely to become hot during heat generation, while minimizing the volume eliminated by the chamfering, and efficiently increasing the energy density of the battery 10A.

[0088] 5(B), the battery 10A according to this embodiment is manufactured by inserting the end of the electrode stack 20, with the corners 21A chamfered, into the opening 43 of the case body 42. This reduces interference between the opening 43 of the case body 42 and the corners 21A of the electrode stack 20, improving the ease of insertion of the electrode stack 20 into the battery case 40. Furthermore, this method makes it possible to obtain a battery 10A with increased energy density. [Explanation of symbols]

[0089] 10A battery 20 Electrode laminate 21A Corner 32 Resin filler (thermal conductive material) 40 Battery case 42 Case body 43 Opening 44 Terminal wall (lid) 50 Chamfered part 50S chamfered surface W1 First direction (opposite direction of opening) 214 Positive electrode current collector 212 Positive electrode active material layer (positive electrode active material) 211 Solid electrolyte layer (solid electrolyte) 213 Negative electrode active material layer (negative electrode active material) 215 Negative electrode current collector

Claims

1. A battery comprising: a rectangular plate-shaped electrode stack in which a positive electrode current collector, a positive electrode active material, a solid electrolyte, a negative electrode active material, and a negative electrode current collector are stacked; and a battery case in which the electrode stack is housed, The battery case is a case body that forms a cylindrical housing and has rectangular openings on two opposing surfaces; a lid that seals the opening, the electrode stack has chamfered portions obtained by chamfering at least some of a plurality of corners provided at the end portion facing the opening, battery.

2. The chamfered surface of the chamfered portion is a triangular flat surface. The battery of claim 1 .

3. a heat conductive member is disposed inside the battery case between the end portion provided with the chamfered portion and the inner surface of the battery case; The battery according to claim 1 or claim 2.

4. the electrode stack has a greater number of positive electrode current collectors than negative electrode current collectors, The chamfered portion is provided at a corner of the end portion on the negative electrode side in the electrode stack. The battery of claim 3.

5. The chamfered portion is not provided at the corner of the end portion on the positive electrode side in the electrode stack. The battery of claim 4.

6. A method for manufacturing the battery according to claim 1, chamfering at least some of a plurality of corners provided at an end of the electrode stack in a direction facing the opening; a step of inserting the electrode stack into the case body, the step of inserting the end portion with the chamfered corner into the opening of the case body; A method for manufacturing a battery comprising:

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