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 body into a case and suppressing displacement of the electrode body housed in the case.SOLUTION: The battery 10A includes the battery case 40 in which the electrode-stacked body 20 is housed and which forms the rectangular opening 43 by the pair of short-side side walls 421 and the pair of long-side side walls 422, and the protrusion 50 that is formed by bending at least one of the short-side side walls 421 and the long-side side walls 422 and that protrudes toward the outside of the battery case 40 is formed on the corner 43A of the opening 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 describes a battery that includes an electrode assembly and a case that houses the electrode stack (electrode assembly), in which the walls of the case are alternately bent inward and outward and have protrusions that protrude toward the inside of the case. In this battery, the multiple protrusions support the linear portions of the electrode assembly, suppressing displacement of the electrode assembly due to expansion and contraction during charging and discharging. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-092460 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the technology described in Patent Document 1, when inserting the electrode stack into the case, there is a risk that the electrode stack will interfere with the protrusions provided on the wall of the case, and there is room for improvement in terms of improving the ease of inserting the electrode stack into the case.

[0005] In consideration of the above, the present invention aims 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 prevent the electrode stack housed in the battery case from shifting out of position. [Means for solving the problem]

[0006] The battery according to the first aspect of the present invention includes a battery case that houses an electrode stack and has a pair of short side wall portions and a pair of long side wall portions that form a rectangular opening, and at the corners of the opening, at least one of the short side wall portions and the long side wall portion is bent to form a recess that protrudes toward the outside of the battery case.

[0007] The battery according to the first embodiment includes a battery case having a rectangular opening formed by a pair of short-side sidewalls and a pair of long-side sidewalls, and an electrode stack housed inside the battery case. Here, the battery case has a convex portion formed by bending at least one of the short-side sidewalls or the long-side sidewalls at the corners of the opening. The convex portion protrudes toward the outside of the battery case. That is, with this configuration, the opening of the battery case already has an excess length at the corner of the battery case for forming the convex portion. Therefore, for example, during the manufacturing process, when the electrode stack is inserted into the battery case through the opening of the battery case, the excess length before the convex portion is formed suppresses interference between the opening of the battery case and the electrode stack. This improves the ease of insertion of the electrode stack into the battery case. Furthermore, when the electrode stack is housed inside the battery case and the convex portions are formed at the corners of the opening, the excess length disappears, reducing the gap between the sidewalls of the battery case and the electrode stack. This makes it possible to prevent the electrode stack housed in the battery case from shifting in position.

[0008] A battery according to a second aspect of the present invention has the configuration according to the first aspect, wherein the inner surfaces of the short-side sidewall portions and the long-side sidewall portions that face the electrode stack are flat surfaces.

[0009] In the battery according to the second aspect, the inner surfaces of the short-side sidewalls and long-side sidewalls of the battery case that face the electrode stack are flat. Therefore, when the gap between the sidewalls of the battery case and the electrode stack is reduced by the protrusions, the surface of the electrode stack abuts against the flat surfaces, dispersing the restraining force. This prevents the localized restraining force from acting on the surface of the electrode stack.

[0010] A battery according to a third aspect of the present invention has the configuration according to the first or second aspect, wherein the protrusion protrudes in the stacking direction of the electrode stack.

[0011] In the battery according to the third aspect, the protrusions formed on the battery case protrude in the stacking direction of the electrode stack, thereby enabling the electrode stack housed inside the battery case to be well restrained in the stacking direction.

[0012] A battery according to a fourth aspect of the present invention has the configuration according to the first or second aspect, wherein the protrusions protrude in a direction perpendicular to the stacking direction of the electrode stack.

[0013] In the battery according to the fourth aspect, the protrusions formed on the battery case protrude in a direction perpendicular to the stacking direction of the electrode stack, thereby enabling the electrode assembly housed inside the battery case to be effectively restrained in the direction perpendicular to the stacking direction.

[0014] A battery according to a fifth aspect of the present invention has the configuration described in any one of the first to fourth aspects, wherein the convex portion protrudes in a direction that forms an angle in the range of 25° to 70° with the stacking direction of the electrode stack.

[0015] In the battery according to the fifth aspect, the protrusions formed on the battery case protrude in a direction that forms an angle of 25° to 70° with the stacking direction of the electrode stack. Therefore, the amount of protrusion of the protrusions in the stacking direction is reduced compared to a configuration in which the protrusions protrude parallel to the stacking direction. This allows the dimensions of the battery case to be reduced in the stacking direction, thereby enabling miniaturization.

[0016] A battery according to a sixth aspect of the present invention has the configuration described in any one of the first to fifth aspects, wherein the battery case has a recess formed adjacent to the protrusion and recessed in a direction perpendicular to the stacking direction.

[0017] In the battery according to the sixth aspect, a recessed portion recessed in a direction perpendicular to the stacking direction is formed adjacent to the protruding portion protruding in the stacking direction. This allows for a sufficient margin of the outer periphery of the opening of the battery case compared to a configuration without a recessed portion. This further improves the ease of inserting the electrode stack into the case.

[0018] A battery according to a seventh aspect of the present invention has the configuration according to any one of the first to sixth aspects, wherein the battery case has a recess that is recessed in the stacking direction and adjacent to the protrusion.

[0019] In the battery according to the seventh aspect, a recessed portion recessed in the stacking direction is formed adjacent to a protruding portion protruding in the stacking direction. This allows the battery case to have sufficient extra length compared to a configuration without a recessed portion. This further improves the ease of inserting the electrode stack into the case.

[0020] A battery according to an eighth aspect of the present invention has a configuration according to any one of the first to seventh aspects, wherein the thickness of the convex portion is thinner than the thickness of other parts of the short side wall portion and the long side wall portion.

[0021] In the battery according to the eighth embodiment, the thickness of the protrusions is thinner than the thickness of the other parts of the short-side and long-side side walls of the battery case, which makes it easier to bend the side walls when forming the protrusions, compared to when the thickness of the protrusions is the same as the thickness of the other parts of the side walls of the battery case.

[0022] A battery module according to a ninth aspect of the present invention is a battery module including a plurality of batteries according to any one of the first to eighth aspects, and includes a plurality of the battery cases arranged in one direction, an elastic body arranged between the battery cases, and a pair of restraining members that restrain the plurality of battery cases from both sides in the one direction, and the plurality of battery cases are arranged so that the long side wall portion of one of the adjacent battery cases faces the long side wall portion of the other battery case.

[0023] A battery module according to a ninth aspect includes a plurality of battery cases arranged in one direction, an elastic body disposed between the battery cases, and a pair of restraining members that restrain the plurality of battery cases from both sides in one direction. This allows the deformation of the elastic body to absorb expansion and contraction of each battery during charging and discharging. The plurality of battery cases arranged in one direction are arranged such that the long-side sidewall of one adjacent battery case faces the long-side sidewall of the other battery case. In other words, the restraining pressure applied by the restraining members is input to the plurality of battery cases via the long-side sidewalls, which are the large-area portions of the battery cases. In this configuration, the battery cases have protrusions at the corners of the openings that protrude outward from the battery cases, thereby reducing the gap between the long-side sidewalls and the electrode stack. This allows the restraining members to effectively apply the restraining pressure to the electrode stack.

[0024] A tenth aspect of the present invention relates to a method for manufacturing a battery having a battery case that houses an electrode stack and has a pair of short side wall portions and a pair of long side wall portions that form a rectangular opening, and includes the steps of inserting the electrode stack through the opening, and pressing the battery case to bend at least one of the short side wall portions and the long side wall portions into corners of the opening, thereby forming a convex portion that protrudes toward the outside of the battery case.

[0025] In a battery manufacturing method according to a tenth aspect, after inserting an electrode stack through a rectangular opening, the battery case is pressed to form convex portions at the corners of the opening. That is, when inserting the electrode stack, the opening of the battery case has an excess length for forming the convex portions. This reduces interference between the battery case and the electrode stack, improving the ease of inserting the electrode stack into the case. Furthermore, when the electrode stack is housed inside the battery case and convex portions are formed at the corners of the opening, the gap between the sidewalls of the battery case and the electrode stack is reduced. This makes it possible to obtain a battery in which displacement of the electrode stack housed inside the battery case is reduced. [Effects of the Invention]

[0026] 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 can suppress misalignment of the electrode stack housed in the battery case. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 2 is a partially exploded perspective view of the battery module according to the embodiment. [Figure 2] FIG. 1 is a perspective view of a battery according to an embodiment of the present invention. [Figure 3] 3 is a cross-sectional view of the electrode stack, schematically showing a state cut along line 3-3 in FIG. 2. FIG. [Figure 4] 4 is a cross-sectional view of the battery case taken along line 4-4 in FIG. 2.

[0023] FIG. [Figure 5] 5 is a cross-sectional view of the battery case taken along line 5-5 in FIG. 4. FIG. [Figure 6] 6 is a partially enlarged cross-sectional view showing an area P indicated by a two-dot chain line in FIG. 5. FIG. [Figure 7] Schematic diagrams illustrating a method for manufacturing a battery according to this embodiment, in which (A) shows the step of inserting an electrode stack into a battery case, (B) shows the step of joining the electrode stack and an internal terminal, (C) shows the step of joining the case body and the terminal wall portion of the battery case, and (D) shows the step of pressing the battery case. [Figure 8] FIG. 7 is a partially enlarged cross-sectional view corresponding to FIG. 6, showing a first modified example of the battery of the present embodiment. [Figure 9] FIG. 7 is a partially enlarged cross-sectional view corresponding to FIG. 6, showing a second modified example of the battery of the present embodiment. [Figure 10] FIG. 7 is a partially enlarged cross-sectional view corresponding to FIG. 6, showing a third modified example of the battery of the present embodiment. [Figure 11] FIG. 7 is a partially enlarged cross-sectional view corresponding to FIG. 6, showing a fourth modified example of the battery of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0028] A battery module 100 according to this embodiment and a battery 10A included in the battery module 100 will be described below with reference to FIGS. 1 to 7. Note that arrow W1, as appropriate, shown in each drawing indicates a first direction, arrow W2 indicates a second direction, and arrow W3 indicates a third direction. The first, second, and third directions are perpendicular to one another. 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.

[0029] 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.

[0030] 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 that process is achieved. Furthermore, unless otherwise specified in this specification, the term "protruding in the direction of ..." includes both protruding in a direction that coincides with the specified direction indicated by that direction, and protruding in a direction that is inclined relative to the specified direction indicated by that direction.

[0031] (battery module) Fig. 1 is a partially exploded perspective view of a battery module 100. As shown in Fig. 1, the battery module 100 is configured to include a plurality of batteries 10A, elastic bodies 12 arranged between the batteries 10A, and a pair of restraining members 14.

[0032] The plurality of batteries 10A are arranged in the second direction W1 with the first direction W1 as the width direction and the second direction W2 as the thickness direction. The plurality of batteries 10A are, for example, lithium ion secondary batteries, and are electrically connected via bus bars 16. Each battery 10A has a battery case 40 as an exterior member and an electrode stack 20 housed inside the battery case 40. Details of the battery case 40 and the electrode stack 20 will be described later.

[0033] The plurality of batteries 10A described above form a plurality of battery cases 40 arranged in the second direction W2 in the battery module 100. Furthermore, plate- or sheet-shaped elastic bodies 12 are arranged between the battery cases 40.

[0034] The elastic body 12 is formed, for example, in a rectangular plate shape with the second direction W2 as its thickness direction, and serves as a buffer member that absorbs the expansion and contraction of the battery 10A during charging and discharging. The material of the elastic body 12 is not particularly limited, and known materials such as resin and silicone can be appropriately selected. The elastic body 12 may be formed of one of these materials or a layered combination of two or more materials. The elastic body 12 is preferably an insulator in order to prevent short circuits between the batteries 10A. Furthermore, the material of the elastic body 12 is preferably one that has excellent heat insulation properties in order to prevent thermal chain reaction between the batteries 10A in the event of an abnormality. Examples of heat-insulating materials with excellent heat insulation properties include urethane and foamed silicone, and foamed silicone is more preferred, as it functions both as an elastic body and a heat-insulating material. The elastic body 12 of this embodiment is formed, for example, from foamed silicone.

[0035] The dimension of the elastic body 12 in the width direction (second direction W2) is set shorter than the dimension of the battery 10A in the width direction (second direction W2), and the elastic body 12 is disposed at a position spaced apart from the end of the battery case 40 in the width direction. Therefore, when the battery module 100 is constructed, the elastic body 12 is disposed so as not to interfere with a protrusion 50 of the battery case 40, which will be described later.

[0036] The pair of restraining members 14, also referred to as end plates, are arranged on both sides in the second direction W2 of the stack of multiple batteries 10A and elastic bodies 12. The pair of restraining members 14 are rectangular plate-shaped members whose width direction is the first direction W1 and whose thickness direction is the second direction W2, and are made of, for example, resin or metal. The pair of restraining members 14 are connected by a pair of side plates 18 extending in the second direction W2.

[0037] The pair of side plates 18 are arranged, for example, on both sides in the first direction W1 of a stack of multiple batteries 10A, elastic bodies 12, and a pair of restraining members 14. The pair of side plates 18 are members that connect the pair of restraining members 14 in the second direction W2, and both ends in the second direction W2 are connected to the pair of restraining members 14 by connecting members 4 such as bolts.

[0038] With the above configuration, in the battery module 100, the plurality of battery cases 40 arranged in the second direction W2 are constrained from both sides in the second direction W2 by a pair of constraining members 14. This applies a predetermined constraining pressure in the second direction W2 to each battery case 40. The detailed configuration of the battery 10A will be described below.

[0039] (battery) Fig. 2 is a perspective view of a battery 10A according to this embodiment. Fig. 4 is a cross-sectional view of a battery case 40, schematically showing a state cut along line 4-4 in Fig. 2. As shown in Fig. 2, 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.

[0040] (electrode laminate) 3 is a cross-sectional view of the electrode stack 20, schematically illustrating a state cut along line 3-3 in FIG. 2. As shown in FIG. 3, 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.

[0041] The electrode body 21 is formed, for example, in the shape of a 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 protrude from one side of the electrode body 21 in the first direction W1. A plurality of negative electrode current collecting tabs 23 protrude from the other side of the electrode body 21 in the first direction W1.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.).

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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).

[0050] Examples of the binder include the same binders as those exemplified as the binder contained in the solid electrolyte layer.

[0051] 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.

[0052] 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).

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.).

[0059] 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.).

[0060] The electrode stack 20 having the above configuration is placed inside a battery case 40 (see FIG. 5) with a pair of resin sheets 30 as insulating members arranged on both side surfaces in the second direction W2.

[0061] 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.

[0062] Furthermore, the electrode stack 20 having the above configuration has a pair of resin fillers 32 disposed as insulating members on both side surfaces in the third direction W3 (see FIG. 4).

[0063] The material of the resin filler may 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.

[0064] 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.

[0065] (battery case) Fig. 4 is a cross-sectional view of the battery case 40, showing a schematic cut along line 4-4 in Fig. 2. As shown in Fig. 4, the battery case 40 includes a case body 42 that forms a cylindrical housing, and a pair of terminal wall portions 44 that seal 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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 .

[0075] 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.

[0076] Here, Fig. 5 is a cross-sectional view of the battery case 40, schematically showing a state cut along line 5-5 in Fig. 4. Fig. 6 is a partially enlarged cross-sectional view showing an area P indicated by a two-dot chain line in Fig. 5.

[0077] (Convex part) 5 and 6, the battery case 40 has a protrusion 50 formed at a corner 43A of the opening 43, protruding toward the outside of the battery case 40. The protrusion 50 is formed by bending at least one of the short-side side wall 421 and the long-side side wall 422, and is formed by pressing the case body 42 of the battery case 40, as described below.

[0078] As shown in FIG. 6 , for example, the protrusion 50 may protrude in the second direction W2 from the long-side sidewall 422 of the battery case 40. That is, the protrusion 50 protrudes in the stacking direction of the electrode stack 20. The protrusion 50 is formed by bending the end of the long-side sidewall 422 corresponding to the corner 43A into a substantially U-shape protruding in the second direction W2. As a result, the protrusion 50 forms a flat surface together with the short-side sidewall 421 of the case main body 42. On the other hand, the protrusion 50 is integrally formed by bending the end of the long-side sidewall 422 of the case main body 42 at a substantially right angle. This allows the electrode stack housed inside the battery case 40 to be well restrained in the stacking direction.

[0079] More specifically, the protrusion 50 has a first side surface 50A provided on one side of the apex 52 and continuous with the short-side side wall 421 of the case body 42, and a second side surface 50B provided on one side of the apex 52 and continuous with the short-side side wall 421 of the case body 42. In this embodiment, the first side surface 50A forms an angle of 0° with the stacking direction of the electrode stack 20 (second direction W2). The second side surface 50B also forms an angle of 0° with the stacking direction of the electrode stack 20. In other words, the protrusion 50 protrudes parallel to the stacking direction of the electrode stack 20.

[0080] 6, the plate thickness T2 of the protrusion 50 is configured to be thinner than the plate thickness T1 of the other portions of the short-side side wall portion 421 and the long-side side wall portion 422. Therefore, when bending the case body 42 by pressing, the bending of the protrusion 50 can be performed more easily than the bending of the other portions of the short-side side wall portion 421 and the long-side side wall portion 422.

[0081] Here, in Fig. 6, the outer shape of the case body 42 before the protrusion 50 is formed is shown by a two-dot chain line. As shown in Fig. 6, in the case body 42, the cross-sectional area of ​​the opening 43 is designed to be sufficiently larger than the cross-sectional area of ​​a cross section of the electrode stack 20 (electrode body 21) cut along the second direction W2 when the protrusion 50 is not formed in the portion corresponding to the corner 43A. In other words, before the protrusion 50 is formed, it can be said that an excess portion is provided on the outer periphery of the opening 43. Therefore, when the electrode stack 20 is inserted into the case body 42 in this state, interference between the case body 42 and the electrode stack 20 is suppressed.

[0082] 6, when protrusions 50 are formed at corners 43A of opening 43, there is no excess length on the outer periphery of opening 43, and the gap between the side wall of case body 42 and electrode stack 20 is reduced. This allows electrode stack 20 to be well restrained within battery case 40.

[0083] In particular, when the electrolyte layer contains a solid electrolyte, as in the electrode stack 20 of this embodiment, this aspect of the present embodiment is more beneficial in terms of improving the restraint performance of the electrode stack 20 within the battery case 40. That is, when the electrolyte layer contains a solid electrolyte, it is known that the amount of expansion and contraction during charge and discharge is smaller than in secondary batteries using liquid electrolytes. Therefore, if the dimensional tolerance of the battery case is determined with priority given to the ease of insertion of the electrode stack 20, the gap between the side wall of the case body and the electrode stack becomes large, which can easily cause misalignment within the battery case. In contrast, this embodiment can increase the dimensional tolerance (excess length) of the case body 42 when inserting the electrode stack 20, and can reduce the dimensional tolerance (excess length) of the case body 42 after inserting the electrode stack 20. Therefore, in so-called all-solid-state batteries, the restraint performance of the electrode stack within the battery case can be effectively improved.

[0084] [Battery manufacturing method] A method for manufacturing a battery according to this embodiment will be described below with reference to Fig. 7. The method for manufacturing a battery according to this embodiment is, for example, a method for manufacturing battery 10A. The method for manufacturing a battery includes a preparation step, an insertion step, a resin filling step, a terminal connection step, a sealing step, and a pressing step.

[0085] (preparation process) The preparation step is a step of attaching a pair of resin sheets 30 to both side surfaces in the second direction W2 of the electrode stack 20. The method of attaching the resin sheets 30 is not particularly limited, and any known method may be used.

[0086] (Insertion process) The insertion step is a step of inserting the electrode stack 20 through the opening 43 of the case body 42 (FIG. 7(A)). This step is performed before the protrusions 50 are formed on the case body 42, so the electrode stack 20 is inserted through the opening 43 that does not have the protrusions 50.

[0087] (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.

[0088] (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. 7(B)). 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.

[0089] (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. 7(C)). The sealing method is not particularly limited and may be any known method. In this embodiment, the connection is made by welding.

[0090] (Pressing process) The pressing step is a step of pressing the battery case 40 to form protrusions 50 at the corners 43A of the opening 43. This step can be performed, for example, by pressing both sides of the battery case 40 in the thickness direction (second direction W2) with a first mold 60 and pressing both sides of the battery case 40 in the height direction (third direction W3) with a second mold 62. At this time, gaps 64 are formed between the first mold 60 and the second mold 62 at positions corresponding to the corners 43A of the battery case 40. When the battery case 40 is pressed from two directions in this state, excess length on the outer periphery of the opening 43 gathers in the gaps 64, and protrusions 50 corresponding to the shape of the gaps 64 are formed.

[0091] (Action and effect) As described above, the battery 10A according to this embodiment includes a battery case 40 having a rectangular opening 43 formed by a pair of short-side sidewalls 421 and a pair of long-side sidewalls 422, and an electrode stack 20 accommodated inside the battery case 40. The battery case 40 has a protrusion 50 formed by bending at least one of the short-side sidewalls 421 and the long-side sidewalls 422 at a corner 43A of the opening 43. The protrusion 50 protrudes outward from the battery case 40. In other words, with this configuration, the opening 43 of the battery case 40 already has an excess length at the position of the corner 43A of the battery case 40 for forming the protrusion 50. Therefore, as shown in FIG. 7(B) , during the manufacturing process of inserting the electrode stack 20 into the case main body 42 through the opening 43 of the case main body 42, the excess length before the protrusion 50 is formed prevents interference between the opening 43 of the case main body 42 and the electrode stack 20. This improves the ease of insertion of the electrode stack 20 into the battery case 40. Furthermore, when the electrode stack 20 is housed inside the battery case 40 and the convex portions 50 are formed at the corners 43A of the opening 43, there is no excess length, and the gap between the side wall of the battery case 40 and the electrode stack 20 is reduced. This makes it possible to prevent the electrode stack 20 housed in the battery case 40 from shifting out of position.

[0092] Furthermore, in this embodiment, the inner surfaces of the short-side sidewall portion 421 and the long-side sidewall portion 422 of the battery case 40 that face the electrode stack 20 are configured as flat surfaces. Therefore, in a state in which the protrusions 50 are provided and the gap between the sidewall portion of the battery case 40 and the electrode stack 20 is reduced, the surface of the electrode stack 20 abuts against the flat surfaces, and the restraining force is dispersed. This prevents the localized restraining force from acting on the surface of the electrode stack 20.

[0093] Furthermore, in this embodiment, the protrusions 50 formed on the battery case 40 protrude in the stacking direction (second direction W2) of the electrode stack 20. This allows the electrode stack 20 housed inside the battery case 40 to be well restrained in the stacking direction.

[0094] 6, the plate thickness T2 of the protrusion 50 is thinner than the plate thickness T1 of the other portions of the short-side side wall 421 and the long-side side wall 422 of the battery case 40. This makes it easier to bend the side wall when forming the protrusion, compared to when the plate thickness of the protrusion is the same as the other portions of the side wall of the battery case 40.

[0095] Furthermore, in this embodiment, when a battery module 100 is configured with a plurality of batteries 10A, the battery module 100 is configured to include a plurality of battery cases 40 arranged in the second direction W2 (one direction), an elastic body 12 arranged between the battery cases 40, and a pair of restraining members 14 that restrain the plurality of battery cases 40 from both sides in the second direction W2. This allows the deformation of the elastic body 12 to absorb expansion and contraction of each battery 10A during charging and discharging (FIG. 1).

[0096] Here, the multiple battery cases 40 arranged in the second direction W2 are arranged so that one long-side sidewall 422 of an adjacent battery case 40 faces the long-side sidewall 422 of the other battery case 40. In other words, the confining pressure applied by the pair of constraining members 14 is input to the multiple battery cases 40 via the long-side sidewalls 422, which are large-area portions of the battery cases 40. In this configuration, the case body 42 of the battery case 40 has protrusions 50 that protrude toward the outside of the battery case 40 at corners 43A of the opening 43, thereby reducing the gap between the long-side sidewalls 422 and the electrode stack 20. This allows the constraining members 14 to effectively apply confining pressure to the electrode stack 20.

[0097] Although one embodiment of the present invention has been described above, the present invention is not limited to the configuration of the above embodiment. For example, the shape of the protrusions formed at the corners of the battery case 40 is not limited to the configuration of the above embodiment. Below, several modifications that can be applied to the above embodiment will be listed and described. In each modification, components that are the same as those in the above embodiment will be assigned the same numbers and their description will be omitted.

[0098] (First Modification) A battery 10B according to a first modification will be described with reference to FIG. 8. FIG. 8 is a partially enlarged cross-sectional view corresponding to FIG. 6, showing an enlarged cross-section of a corner 43A of the battery case 40. As shown in this figure, a protrusion 70 is formed at the corner 43A of the opening 43 of the battery case 40, and this protrusion 70 protrudes in a direction perpendicular to the stacking direction of the electrode stack 20 (third direction W3). The protrusion 70 is formed by bending the end of the short-side side wall 421 corresponding to the corner 43A into a substantially U-shape protruding in the third direction W3. As a result, the protrusion 70 forms a flat surface together with the long-side side wall 422 of the case main body 42. Meanwhile, the protrusion 70 is integrally formed by bending the end of the short-side side wall 421 of the case main body 42 at a substantially right angle.

[0099] More specifically, the protrusion 70 has a first side surface 70A provided on one side of the apex 72 and continuous with the short-side side wall portion 421 of the case body 42, and a second side surface 70B provided on the other side of the apex 72 and continuous with the long-side side wall portion 422 of the case body 42. The first side surface 70A forms an angle of 90° with the stacking direction of the electrode stack 20 (second direction W2). The second side surface 70B also forms an angle θ1 with the stacking direction of the electrode stack 20, which is also 90°. As a result, the protrusion 70 protrudes parallel to the direction perpendicular to the stacking direction of the electrode stack 20.

[0100] The battery 10B according to the first modification basically follows the configuration of the battery 10A according to the above embodiment, and therefore can achieve the same functions and effects. Furthermore, in this modification, the protrusions 50 formed on the battery case 40 protrude in a direction (third direction W3) perpendicular to the stacking direction of the electrode stack 20. This allows the electrode stack 20 housed inside the battery case 40 to be well restrained in the direction perpendicular to the stacking direction.

[0101] (Second Modification) A battery 10C according to a second modified example will be described with reference to Fig. 9. Fig. 9 is a partially enlarged cross-sectional view corresponding to Fig. 6, showing an enlarged cross-section of a corner 43A of the battery case 40. As shown in this figure, a protrusion 80 is formed at the corner 43A of the opening 43 of the battery case 40, and this protrusion 80 protrudes in a direction forming a predetermined angle with the stacking direction of the electrode stack 20. The angle formed between the protruding direction of the protrusion 80 and the stacking direction of the electrode stack 20 is preferably set in the range of 25° to 70°, and in this modified example, it is set to 45°, for example.

[0102] The protrusions 80 protrude in the stacking direction (second direction W2) of the electrode stack 20. The protrusions 80 are formed by bending the ends of the long-side sidewalls 422 corresponding to the corners 43A into a generally U-shape that protrudes in the second direction W2. As a result, the protrusions 80 form a flat surface together with the short-side sidewalls 421 of the case body 42. Meanwhile, the protrusions 80 are integrally formed by bending the ends of the long-side sidewalls 422 of the case body 42 at an angle that corresponds to the protruding direction of the protrusions 50.

[0103] More specifically, the protrusion 80 has a first side surface 80A provided on one side of the apex 82 and continuous with the short-side side wall portion 421 of the case body 42, and a second side surface 80B provided on the other side of the apex 82 and continuous with the long-side side wall portion 422 of the case body 42. The first side surface 80A forms an angle of 0° with the stacking direction of the electrode stack 20 (second direction W2). On the other hand, the second side surface 80B forms an angle θ2 of 45° with the stacking direction of the electrode stack 20. As a result, the protrusion 80 protrudes in a direction forming an angle of 45° with the stacking direction of the electrode stack 20.

[0104] The battery 10C according to the second modification basically follows the configuration of the battery 10A according to the above embodiment, and therefore can achieve the same functions and effects. Furthermore, in this modification, the protrusions 80 protrude in a direction that forms an angle of 25° to 70° with the stacking direction of the electrode stack 20. Therefore, the amount of protrusion of the protrusions in the stacking direction is reduced compared to a configuration in which the protrusions protrude parallel to the stacking direction. This allows the dimensions of the battery case to be reduced in the stacking direction (second direction W2), thereby achieving miniaturization.

[0105] (Third Modification) A battery 10D according to a third modified example will be described with reference to Fig. 10. Fig. 10 is a partially enlarged cross-sectional view corresponding to Fig. 6, showing an enlarged cross-section of a corner 43A of the battery case 40. As shown in this figure, a protrusion 90 is formed at the corner 43A of the opening 43 of the battery case 40, and this protrusion 90 protrudes in a direction forming a predetermined angle with the stacking direction of the electrode stack 20. The angle formed between the protruding direction of the protrusion 90 and the stacking direction of the electrode stack 20 is preferably set in the range of 25° to 70°, and in this modified example, it is set to 70°, for example.

[0106] The protrusions 90 protrude in the stacking direction (second direction W2) of the electrode stack 20 and in a direction (first direction W1) perpendicular to the stacking direction. The protrusions 90 are formed by bending the ends of the long-side side wall portions 422 and the short-side side wall portions 421 corresponding to the corner portions 43A into a substantially U-shape protruding in the second direction W2 and the third direction W3. As a result, recesses 94 recessed in a direction perpendicular to the stacking direction are formed adjacent to the protrusions 90 in the short-side side wall portions 421 of the case body 42. The protrusions 90 are also formed integrally with the long-side side wall portions 422 of the case body 42 by bending the ends of the long-side side wall portions 422 at an angle corresponding to the protruding direction of the protrusions 90.

[0107] More specifically, the protrusion 90 has a first side surface 90A provided on one side of the apex 92 and continuous with the short-side sidewall 421 of the case body 42, and a second side surface 90B provided on the other side of the apex 92 and continuous with the long-side sidewall 422 of the case body 42. The first side surface 90A, together with the short-side sidewall 421, defines a recess 94. The second side surface 90B is inclined in a direction such that the angle θ3 formed with the stacking direction of the electrode stack 20 is 70°. As a result, the protrusion 90 protrudes in a direction that forms an angle of 70° with the stacking direction of the electrode stack 20.

[0108] The battery 10D according to the third modification basically follows the configuration of the batteries 10A and 10C according to the above-described embodiment and the second modification, and therefore can achieve the same functions and effects. Furthermore, in this modification, a recess 94 recessed in a direction perpendicular to the stacking direction (first direction W1) is formed adjacent to the protrusion 90 protruding in the stacking direction. Therefore, compared to a configuration without the recess 94, a sufficient margin of outer periphery can be secured at the opening 43 of the battery case 40. This further improves the ease of insertion of the electrode stack 20 into the battery case 40.

[0109] (Fourth Modification) A battery 10E according to a fourth modification will be described with reference to Fig. 11. Fig. 11 is a partially enlarged cross-sectional view corresponding to Fig. 6, showing an enlarged cross-section of a corner 43A of a battery case 40. As shown in this figure, a protrusion 110 is formed at the corner 43A of the opening 43 of the battery case 40, and this protrusion 110 protrudes parallel to the stacking direction of the electrode stack 20, similar to the protrusion 50 of the above-described embodiment.

[0110] Here, a recess 114 recessed in the stacking direction (second direction W2) is formed adjacent to the protrusion 110 in the long-side side wall portion 422 of the case body 42. This also means that the top 111 of the protrusion 110 is positioned so as not to protrude in the second direction W2 relative to the long-side side wall portion 422.

[0111] The protrusion 110 is formed by bending an end of the long-side side wall 422 corresponding to the corner 43A into a substantially U-shape that protrudes in the second direction W2. On the other hand, the recess 114 is provided between the protrusion 110 and the long-side side wall 422, and is formed by bending an end of the long-side side wall 422 into a substantially U-shape that is recessed in the second direction W2. The protrusion 110 forms a flat surface together with the short-side side wall 421 of the case main body 42. The protrusion 110 is also formed integrally with the recess 114 by bending an end of the long-side side wall 422 of the case main body 42 into a substantially S-shape.

[0112] The battery 10E according to the fourth modification basically follows the configuration of the above-described embodiment, and therefore can achieve the same functions and effects. Furthermore, in this modification, a recess 114 recessed in the stacking direction is formed adjacent to the protrusion 110 protruding in the stacking direction. Therefore, compared to a configuration without the recess 114, a sufficient margin of outer periphery can be secured at the opening 43 of the case body 42. This further improves the ease of inserting the electrode stack into the battery case 40.

[0113] Furthermore, in this modification, by forming the recess 114, the top 111 of the protrusion 110 is positioned so as not to protrude in the second direction W2 relative to the long-side sidewall 422. This allows the dimensions of the battery case 40 to be reduced in the stacking direction (second direction W2), thereby enabling miniaturization. [supplementary explanation]

[0114] Although one embodiment of the present invention and several modified examples have been described above, the present invention allows substitutions and modifications of each configuration within the scope of the gist of the invention. It is also possible to apply a combination of the configurations of the embodiment and the modified examples.

[0115] In the above embodiment and modified example, the electrolyte layer of the electrode stack has been described as including a solid electrolyte, but the present invention is not limited to this, and the configuration of the present invention may be applied to a battery in which the electrolyte layer includes a liquid electrolyte. [Explanation of symbols]

[0116] 100 battery modules 10A,10B,10C,10D,10E battery 20 Electrode laminate 40 Battery case 42 Case body (battery case) 43 Opening 421 Short side wall 422 Long side wall 50,70,80,90,110 Convex part 94 Concave (concave recessed in the direction perpendicular to the stacking direction) 114 Concave portion (concave portion recessed in the stacking direction)

Claims

1. a battery case that houses the electrode stack and has a rectangular opening formed by a pair of short-side sidewalls and a pair of long-side sidewalls; At least one of the short-side sidewall portion and the long-side sidewall portion is bent at a corner of the opening portion to form a convex portion that protrudes toward the outside of the battery case. battery.

2. the inner surfaces of the short-side sidewall portions and the long-side sidewall portions facing the electrode stack are configured as flat surfaces; The battery of claim 1 .

3. The protrusion protrudes in the stacking direction of the electrode stack. The battery of claim 1 .

4. The protrusions protrude in a direction perpendicular to the stacking direction of the electrode stack. The battery of claim 1 .

5. The protrusions protrude in a direction in which the angle formed with the stacking direction of the electrode stack is in the range of 25° to 70°. The battery of claim 1 .

6. The battery case has a recess formed adjacent to the protrusion and recessed in a direction perpendicular to the stacking direction. The battery of claim 3.

7. The battery case has a recess formed adjacent to the protrusion and recessed in the stacking direction. The battery of claim 3.

8. the thickness of the protrusion is thinner than the thickness of other portions of the short-side side wall portions and the long-side side wall portions; The battery of claim 1 .

9. A battery module comprising a plurality of the batteries according to claim 1, A plurality of the battery cases arranged in one direction; an elastic body disposed between the battery cases; a pair of restraining members that restrain the plurality of battery cases from both sides in the one direction, The plurality of battery cases are arranged such that the long-side sidewall portion of one of the adjacent battery cases faces the long-side sidewall portion of the other battery case. Battery module.

10. A method for manufacturing a battery including a battery case that houses an electrode stack and has a rectangular opening formed by a pair of short side wall portions and a pair of long side wall portions, the method comprising: inserting the electrode stack through the opening; and pressing the battery case to bend at least one of the short-side sidewall portions and the long-side sidewall portions at a corner of the opening, thereby forming a convex portion that protrudes toward the outside of the battery case. How batteries are manufactured.

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