Secondary battery

Abstract

The invention provides a secondary battery. The housing body (110) includes a pair of first walls (111) facing each other in a second direction orthogonal to the first direction, and a pair of second walls (112) facing each other in a third direction orthogonal to the first direction and the second direction, the area of the pair of first walls (111) is larger than the area of the pair of second walls (112), and one of the pair of second walls (112) is larger than the area of the other of the pair of second walls (112). One of the pair of second walls (112) is provided with an exhaust valve (150) that breaks when the pressure in the housing (100) is equal to or greater than a predetermined value, and the other of the pair of second walls (112) is provided with a joining section (115) that extends in the first direction.

Description

Technical Field The present technology relates to a secondary battery. Background Art Japanese Patent Application Laid-Open No. 2001-143664 discloses a technique for forming a safety valve by forming a thin-walled portion on any side surface of a rectangular housing except for a terminal surface and a bottom surface. As the capacity of batteries increases, secondary batteries are becoming larger. From the perspective of the reliability of large secondary batteries, the battery described in Japanese Patent Application Publication No. 2001-143664 still has room for further improvement. The purpose of this technology is to provide a secondary battery with high capacity and high reliability. Summary of the invention The present technology provides the following secondary batteries.

[0001] A secondary battery comprises: an electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode; and a shell that accommodates the electrode body, the shell comprising: a shell body having a first opening located at an end portion of a first side in a first direction, and a second opening located at an end portion of a second side opposite to the first side in the first direction; a first sealing plate that seals the first opening; and a second sealing plate that seals the second opening, the shell body comprising a pair of first walls that face each other in a second direction orthogonal to the first direction, and a pair of second walls that face each other in a third direction orthogonal to the first direction and the second direction, the area of ​​the pair of first walls being larger than the area of ​​the pair of second walls, a vent valve that breaks when the pressure in the shell becomes greater than a specified value being provided on one of the pair of second walls, and a joint extending along the first direction being provided on the other of the pair of second walls.

[0002] In the secondary battery described in [1], the exhaust valve includes a thin-walled portion or a groove portion formed in one of the pair of second walls.

[0003] In the secondary battery described in [1] or [2], the electrode body includes: a main body; a first electrode sheet, which is electrically connected to the first electrode and is located on the first side relative to the main body; and a second electrode sheet, which is electrically connected to the second electrode and is located on the second side relative to the main body, the first electrode sheet is electrically connected to the first electrode terminal provided on the first sealing plate, and the second electrode sheet is electrically connected to the second electrode terminal provided on the second sealing plate.

[0004] In the secondary battery described in [1] or [2], the electrode body includes: a main body; a first electrode sheet, which is electrically connected to the first electrode and is located on the first side relative to the main body; and a second electrode sheet, which is electrically connected to the second electrode and is located on the second side relative to the main body, and at least a portion of the exhaust valve is arranged in a first end region of the electrode body that is closer to the first opening than the main body in the first direction, and at least a portion of the exhaust valve is arranged in a second end region of the electrode body that is closer to the second opening than the main body in the first direction.

[0005] In the secondary battery described in any one of [1] to [4], the electrode body includes a first electrode body and a second electrode body, the first electrode body and the second electrode body are respectively wound electrode bodies, the first electrode body and the second electrode body are arranged adjacent to each other, the first electrode body includes a first curved surface opposite to one of a pair of second walls, the first curved surface has a first vertex closest to one of the pair of second walls, the second electrode body includes a second curved surface opposite to one of the pair of second walls, the second curved surface has a second vertex closest to one of the pair of second walls, and at least a portion of the exhaust valve is arranged in an area between the first vertex and the second vertex in the second direction.

[0006] In the secondary battery described in any one of [1] to [5], the secondary battery further comprises an insulating sheet covering at least a portion of the periphery of the electrode body, the insulating sheet comprising a first end side and a second end side extending along a first direction, the first end side and the second end side being arranged at a position opposite to one of a pair of second walls, and an area where the insulating sheet is overlapped into a double layer is provided between the first end side and the second end side.

[0007] In the secondary battery described in any one of [1] to [6], the exhaust valve is disposed in a plurality of regions separated from each other on one of the pair of second walls.

[0008] In the secondary battery described in any one of [1] to [7], a thin-walled region having a relatively small thickness of the case body is formed on one of the pair of second walls, and the exhaust valve is arranged inside the thin-walled region.

[0009] In the secondary battery described in any one of [1] to [8], the joining portion is arranged at a position offset from the center of the other of the pair of second walls toward an arbitrary end portion in the second direction. The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 This is a front view showing the structure of a secondary battery according to one embodiment of the present technology. Figure 2It means observing from the direction of arrow II Figure 1 A diagram showing the state of a secondary battery. Figure 3 It means observing from the direction of arrow III Figure 1 A diagram showing the state of a secondary battery. Figure 4 It means observing from the direction of arrow IV Figure 1 A diagram showing the state of a secondary battery. Figure 5 It means when viewed from the direction of arrow V Figure 1 A diagram showing the state of a secondary battery. Figure 6 yes Figure 1 A front cross-sectional view of a secondary battery is shown. Figure 7 It is a front view showing a negative electrode original plate before forming a negative electrode plate. Figure 8 yes Figure 7 The VIII-VIII cross-sectional view of the negative electrode original plate shown. Fig. 9 It is a front view showing a negative electrode plate formed from a negative electrode original plate. Fig.10 It is a front view showing a positive electrode original plate before forming a positive electrode plate. Fig.11 yes Fig.10 XI-XI cross-sectional view of the positive electrode original plate shown. Fig.12 It is a front view showing a positive electrode plate formed from a positive electrode original plate. Fig.13 It is a diagram showing an electrode body and a current collector taken out from a secondary battery. Fig.14 It is a front view of the connection structure between the negative electrode sheet group and the negative electrode collector. Fig.15 It is a cross-sectional view of the connection structure between the negative electrode sheet group and the negative electrode current collector. Fig.16 It is a diagram showing the step of inserting the electrode body into the case body. Fig.17 This is a diagram showing a step of placing a separator between a sealing plate and an electrode body. Fig.18 It is a diagram showing a plate-shaped member constituting the casing body. Fig.19 It means that Fig.18 The diagram shows a plate-like member in a bent state. Fig. 20 This is a diagram showing an example of the arrangement of the electrode bodies and the insulating sheets inside the case body. Fig.21 This is an expanded view of the insulating sheet. Fig. 22 It is a front view showing the electrode body and the insulating sheet. Fig.23 It is a diagram showing a modified example of the arrangement of the electrode bodies and the insulating sheets inside the case body. Fig.24 This is a diagram showing the upper portion of a plurality of wound electrode bodies. Fig.25 This is a diagram showing the arrangement of exhaust valves (part 1). Fig.26 This is a diagram showing the arrangement of the exhaust valve (part 2). Fig. 27 This is a diagram showing the arrangement of the exhaust valve (part 3). Fig.28 This is a diagram showing the arrangement of the exhaust valve (part 4). Fig.29 This is a diagram showing the arrangement of the exhaust valve (part 5). Fig.30 This is a diagram showing the configuration of the exhaust valve (part 6). Fig.31 This is a diagram showing the configuration of the exhaust valve (part 7). Fig.32 This is a diagram showing the configuration of the exhaust valve (part eight). Fig.33 This is a diagram showing the configuration of the exhaust valve (No. 9). Fig.34 yes Fig.33 XXXIV-XXXIV section view in the figure. Fig.35 It is an enlarged cross-sectional view showing an example of a groove portion constituting the exhaust valve. Fig.36 It is a diagram for explaining the arrangement of the exhaust valves in the first direction. DETAILED DESCRIPTION Hereinafter, embodiments of the present technology will be described. In addition, the same reference numerals are given to the same or corresponding parts, and the description thereof may not be repeated. In addition, in the embodiments described below, when the number, amount, etc. are mentioned, the scope of the present technology is not necessarily limited to the number, amount, etc., unless otherwise specified. In addition, in the following embodiments, except for the cases where there are special records, each component is not necessarily essential to the present technology. In addition, the present technology is not necessarily limited to the technology that has all the effects mentioned in the present embodiment. In addition, in this specification, the descriptions of "comprise", "include", and "have" are open forms. That is, when a certain structure is included, other structures other than the structure may or may not be included. In addition, in this specification, when geometrical terms and terms indicating position and direction relationships are used, such as "parallel", "orthogonal", "oblique 45 degrees", "coaxial", "along", etc., these terms allow for manufacturing errors or some changes. In this specification, when terms such as "upper side" and "lower side" are used to indicate relative positional relationships, these terms are used to indicate relative positional relationships in one state, and the relative positional relationship can be reversed or rotated to any angle depending on the installation direction of each mechanism (for example, turning the entire mechanism upside down, etc.). In this specification, "secondary battery" is not limited to lithium-ion batteries, and may include other secondary batteries such as nickel-hydrogen batteries, sodium-ion batteries, and solid electrolyte secondary batteries. In this specification, "electrode" may be collectively referred to as positive electrode and negative electrode. In addition, in the drawings, the direction along the winding axis of the electrode body of the secondary battery is set as the X direction as the first direction, the short side direction of the electrode body perpendicular to the first direction and observed from the first direction is set as the Y direction as the second direction, and the long side direction of the electrode body perpendicular to the first direction and observed from the first direction is set as the Z direction as the third direction. In addition, in order to facilitate the understanding of the invention, there are parts in which the dimensions of each structure in the drawings are changed from the actual dimensions. In the present application specification, the first direction (X direction) is sometimes referred to as the “width direction” of the secondary battery or the shell body, the second direction (Y direction) is similarly referred to as the “thickness direction” of the secondary battery or the shell body, and the third direction (Z direction) is similarly referred to as the “height direction” of the secondary battery or the shell body. (Overall structure of the battery) Figure 1 It is a front view of the secondary battery 1 according to the present embodiment. Figure 2 to Figure 5 They are respectively viewed from the direction of arrow II, arrow III, arrow IV, and arrow V. Figure 1 The diagram shows the state of the secondary battery 1. Figure 6 yes Figure 1 The secondary battery 1 is shown in front cross-sectional view. The secondary battery 1 can be mounted on an electric vehicle (BEV), a plug-in hybrid electric vehicle (PHEV), a hybrid electric vehicle (HEV), etc. However, the use of the secondary battery 1 is not limited to vehicle-mounted use. like Figure 1 to Figure 6 As shown, the secondary battery 1 includes a case 100 , an electrode body 200 , an electrode terminal 300 , and a current collector 400 . The case 100 includes a case body 110 , a first sealing plate 120 , and a second sealing plate 130 . When forming a battery pack including secondary batteries 1, a plurality of secondary batteries 1 are stacked in their thickness direction. The stacked secondary batteries 1 may be constrained in the stacking direction (Y direction) by a constraining member to form a battery module, or the battery pack may be directly supported on the side of the battery pack housing without using a constraining member. The case body 110 is formed of a cylindrical, preferably rectangular, member. This provides a rectangular secondary battery 1. The case body 110 is made of metal. Specifically, the case body 110 is made of aluminum, aluminum alloy, iron, or iron alloy. like Figure 1 , Figure 2 As shown in FIG. 1 , a first sealing plate 120 and a second sealing plate 130 are provided at both ends of the housing body. The housing body 110 is formed by, for example, bringing the ends of the plate-like members subjected to bending into contact with each other (at Figure 2 The joint portion 115 shown in the example in the figure can be formed into a square tube shape by joining them together (for example, laser welding). The corner of the "square tube shape" can also have an R shape. The joint portion 115 in this embodiment extends along the first direction (X direction) on the outer peripheral surface of the shell body 110. In the present embodiment, the shell body 110 is formed in the width direction (X direction) of the secondary battery 1 to be longer than the thickness direction (Y direction) and the height direction (Z direction) of the secondary battery 1. The dimension (width) of the shell body 110 in the X direction is preferably more than 30 cm. Thus, a relatively large (high capacity) secondary battery 1 can be formed. The dimension (height) of the shell body 110 in the Z direction is preferably less than 20 cm, more preferably less than 15 cm, and further preferably less than 10 cm. Thus, a secondary battery 1 with a relatively low height (low height) can be formed, for example, the mountability on a vehicle is improved. The housing body 110 includes a pair of first side portions 111 (first wall) and a pair of second side portions 112 (second wall). The pair of first side portions 111 constitute a portion of the side of the housing 100. The pair of second side portions 112 constitute an upper surface portion 112A and a bottom surface portion 112B of the housing 100. The pair of first side portions 111 and the pair of second side portions 112 are arranged to intersect each other. The pair of first side portions 111 and the pair of second side portions 112 are connected at their respective ends. The area of ​​each of the pair of first side portions 111 is larger than the area of ​​each of the pair of second side portions 112. like Figure 3 As shown, a first opening 113 is provided at the end of the first side in the first direction (X direction) of the housing body 110. The first opening 113 is sealed by a first sealing plate 120. The first opening 113 and the first sealing plate 120 have a substantially rectangular shape with the Y direction being the short side direction and the Z direction being the long side direction. The first sealing plate 120 is provided with a negative electrode terminal 301 (first electrode terminal) and a liquid injection hole 121. The positions of the negative electrode terminal 301 and the liquid injection hole 121 can be changed as appropriate. The first sealing plate 120 can be joined to the case body 110 by laser welding, for example. like Figure 4 As shown, a second opening 114 is provided at the end of the second side opposite to the first side in the first direction (X direction) of the housing body 110. The second opening 114 is sealed by a second sealing plate 130. The second opening 114 and the second sealing plate 130 have a substantially rectangular shape with the Y direction being the short side direction and the Z direction being the long side direction. The second sealing plate 130 is provided with a positive electrode terminal 302 (second electrode terminal) and a liquid injection hole 131. The positions of the positive electrode terminal 302 and the liquid injection hole 131 can be changed as appropriate. The second sealing plate 130 can be joined to the case body 110 by laser welding, for example. The first sealing plate 120 and the second sealing plate 130 are made of metal. Specifically, the first sealing plate 120 and the second sealing plate 130 are made of aluminum, aluminum alloy, iron, iron alloy, or the like. In one example, the thickness of each of the first sealing plate 120 and the second sealing plate 130 is thicker than the thickness (plate thickness) of the case body 110 . The negative electrode terminal 301 is electrically connected to the negative electrode of the electrode body 200 . The negative electrode terminal 301 is attached to the first sealing plate 120 , that is, the case 100 . The positive electrode terminal 302 is electrically connected to the positive electrode of the electrode body 200 . The positive electrode terminal 302 is attached to the second sealing plate 130 , that is, the case 100 . The negative electrode terminal 301 is made of a conductive material (more specifically, a metal), for example, copper or a copper alloy, etc. A portion or layer made of aluminum or an aluminum alloy may be provided on the outer surface of the negative electrode terminal 301 . The positive electrode terminal 302 is made of a conductive material (more specifically, a metal), and can be made of, for example, aluminum or an aluminum alloy. The liquid injection holes 121 and 131 are sealed by a sealing member (not shown). As the sealing member, for example, a blind rivet or other metal member can be used. like Figure 5 As shown, an exhaust valve 150 is provided on the upper surface portion 112A of the housing 100. The exhaust valve 150 is formed to extend along the X direction. The exhaust valve 150 is a thin-walled portion formed on the upper surface portion 112A of the housing 100. The exhaust valve 150 breaks when the pressure in the housing 100 becomes greater than a predetermined value, thereby exhausting the gas in the housing 100 to the outside. The electrode body 200 is a flat electrode body having a positive electrode plate and a negative electrode plate described later. Specifically, the electrode body 200 is a wound electrode body formed by winding a strip-shaped positive electrode plate and a strip-shaped negative electrode plate together via a strip-shaped separator not shown. However, in this specification, the "electrode body" is not limited to a wound electrode body, and can also be a stacked electrode body formed by alternately stacking a plurality of positive plates and a plurality of negative plates. The strip-shaped separator can be composed of a polyolefin microporous film, for example. The electrode body includes a plurality of positive plates and a plurality of negative plates, and the positive electrode sheets provided on each positive plate can also be stacked to form a positive electrode sheet group, and the negative electrode sheets provided on each negative plate can also be stacked to form a negative electrode sheet group. like Figure 6 As shown, the case 100 accommodates the electrode body 200. The electrode body 200 is accommodated in the case 100 so that the winding axis thereof is parallel to the X direction. Specifically, a single or a plurality of wound electrode bodies and an electrolyte (electrolyte) not shown are housed together inside an insulating sheet 700 to be described later and arranged in the housing 100. As the electrolyte (non-aqueous electrolyte), for example, an electrolyte obtained by dissolving LiPF6 at a concentration of 1.2 mol / L in a non-aqueous solvent obtained by mixing ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) in a volume ratio (25° C.) of 30:30:40 can be used. In addition, a solid electrolyte may be used instead of the electrolyte. The electrode body 200 includes a main body (a portion where the positive electrode plate and the negative electrode plate are stacked via a separator), a negative electrode sheet group 220 (a first electrode sheet group), and a positive electrode sheet group 250 (a second electrode sheet group). The main body of the electrode body 200 corresponds to the rectangular portion excluding the negative electrode sheet group 220 and the positive electrode sheet group 250. The main body is composed of a negative electrode plate 210 and a positive electrode plate 240 described later. The negative electrode sheet group 220 is located at the end of the electrode body 200 on the first side in the first direction (X direction) relative to the main body. The first side in this embodiment is the first sealing plate 120 side. The positive electrode sheet group 250 is located at the end of the second side in the first direction (X direction) relative to the main body. The second side in this embodiment is the second sealing plate 130 side. The negative electrode sheet group 220 and the positive electrode sheet group 250 are formed so as to protrude from the center portion of the electrode body 200 toward the first sealing plate 120 or the second sealing plate 130 , respectively. The current collector 400 includes a negative electrode current collector 410 (first current collector) and a positive electrode current collector 420 (second current collector). The negative electrode current collector 410 and the positive electrode current collector 420 are each formed of a plate-like member. The electrode body 200 is electrically connected to the negative electrode terminal 301 and the positive electrode terminal 302 via the current collector 400 . The negative electrode current collector 410 is disposed on the first sealing plate 120 via a resin insulating member. The negative electrode current collector 410 is electrically connected to the negative electrode sheet group 220 and the negative electrode terminal 301. The negative electrode current collector 410 is made of a conductive material (more specifically, metal), such as copper or a copper alloy. The positive electrode collector 420 is arranged on the second sealing plate 130 via an insulating member made of resin. The positive electrode collector 420 is electrically connected to the positive electrode sheet group 250 and the positive terminal 302. The positive electrode collector 420 is composed of a conductive material (more specifically, a metal), for example, aluminum or an aluminum alloy. In addition, the positive electrode sheet group 250 can also be electrically connected to the second sealing plate 130 directly or via the positive electrode collector 420. In this case, the second sealing plate 130 can also play the role of the positive terminal 302. (Structure of Electrode Body 200) Figure 7 2 is a front view showing a negative electrode original plate 210S before forming a negative electrode plate 210 (first electrode). Figure 8 yes Figure 7 The VIII-VIII cross-sectional view of the negative electrode original plate 210S shown in FIG. Fig. 9 1 is a front view showing a negative electrode plate 210 formed from a negative electrode original plate 210S. The negative electrode plate 210 is manufactured by processing the negative electrode original plate 210S. Figure 7 and Figure 8 As shown, the negative electrode original plate 210S includes a negative electrode core 211 and a negative electrode active material layer 212. The negative electrode core 211 is a copper foil or a copper alloy foil. The negative electrode core 211 has a negative electrode active material layer 212 formed thereon except for one end portion of both surfaces. The negative electrode active material layer 212 is formed by applying a negative electrode active material layer slurry using a die coater. The negative electrode active material layer slurry is prepared by kneading graphite as a negative electrode active material, styrene butadiene rubber (SBR) and carboxymethyl cellulose (CMC) as binders, and water as a dispersion medium so that the mass ratio of graphite:SBR:CMC is about 98:1:1. The negative electrode core 211 coated with the negative electrode active material layer slurry is dried to remove the water contained in the negative electrode active material layer slurry, thereby forming the negative electrode active material layer 212. Furthermore, the negative electrode original plate 210S including the negative electrode core 211 and the negative electrode active material layer 212 is formed by compressing the negative electrode active material layer 212. The negative electrode original plate 210S is cut into a predetermined shape to form the negative electrode plate 210. The negative electrode original plate 210S can be cut by laser processing based on energy line irradiation, metal mold processing, or tool processing. like Fig. 9 As shown, at one end in the width direction of the negative electrode plate 210 formed by the negative electrode original plate 210S, a plurality of negative electrode sheets 230 formed by the negative electrode core 211 are provided. When the negative electrode plate 210 is wound, the plurality of negative electrode sheets 230 are stacked to form a negative electrode sheet group 220. As a result, the negative electrode sheet group 220 is connected to the negative electrode plate 210 (first electrode). The positions of the respective plurality of negative electrode sheets 230 and the lengths in the protruding direction are appropriately adjusted in consideration of the connection state between the negative electrode sheet group 220 and the negative electrode collector 410. In addition, the shape of the negative electrode sheet 230 is not limited to Fig. 9 The shape illustrated in . Fig.10 2 is a front view showing a positive electrode original plate 240S before forming a positive electrode plate 240 (second electrode). Fig.11 yes Fig.10 The XI-XI cross-sectional view of the positive electrode original plate 240S shown in FIG. Fig.12 1 is a front view showing a positive electrode plate 240 formed of a positive electrode original plate 240S. The positive electrode plate 240 as the second electrode has a different polarity from the negative electrode plate 210 as the first electrode. The positive electrode plate 240 is manufactured by processing a positive electrode original plate 240S. Fig.10 and Fig.11 As shown, the positive electrode original plate 240S includes a positive electrode core 241, a positive electrode active material layer 242, and a positive electrode protective layer 243. The positive electrode core 241 is an aluminum foil or an aluminum alloy foil. The positive electrode core body 241 has a positive electrode active material layer 242 formed thereon except for one end portion of both surfaces. The positive electrode active material layer 242 is formed on the positive electrode core body 241 by applying a positive electrode active material layer slurry using a die coater. The positive electrode active material layer slurry is prepared by kneading lithium nickel cobalt manganese composite oxide as a positive electrode active material, polyvinylidene fluoride (PVdF) as a binding material, a carbon material as a conductive material, and N-methyl-2-pyrrolidone (NMP) as a dispersion medium in such a manner that the mass ratio of lithium nickel cobalt manganese composite oxide:PVdF:carbon material becomes approximately 97.5:1:1.5. The positive electrode protection layer 243 is in contact with the positive electrode core 241 and is formed at one end of the positive electrode active material layer 242 in the width direction. The positive electrode protection layer 243 is formed on the positive electrode core 241 by applying the positive electrode protection layer slurry using a die coater. The positive electrode protection layer 243 has a resistance greater than that of the positive electrode active material layer 242. The positive electrode protective layer slurry was prepared by kneading alumina powder, a carbon material as a conductive material, PVdF as a binder, and NMP as a dispersion medium so that the mass ratio of alumina powder:carbon material:PVdF was about 83:3:14. The positive electrode core 241 coated with the positive electrode active material layer slurry and the positive electrode protective layer slurry is dried to remove the NMP contained in the positive electrode active material layer slurry and the positive electrode protective layer slurry, thereby forming the positive electrode active material layer 242 and the positive electrode protective layer 243. Furthermore, by compressing the positive electrode active material layer 242, a positive electrode original plate 240S including the positive electrode core 241, the positive electrode active material layer 242 and the positive electrode protective layer 243 is formed. The positive electrode original plate 240S is formed by cutting the positive electrode original plate 240S into a predetermined shape. The positive electrode original plate 240S can be cut by laser processing based on energy line irradiation, metal mold processing, or tool processing. like Fig.12 As shown, at one end portion in the width direction of the positive electrode plate 240 formed by the positive electrode original plate 240S, a plurality of positive electrode sheets 260 formed by the positive electrode core 241 are provided. When the positive electrode plate 240 is wound, the plurality of positive electrode sheets 260 are stacked to form a positive electrode sheet group 250. Thus, the positive electrode sheet group 250 is in a state of being connected to the positive electrode plate 240 (the second electrode). The positions of the respective plurality of positive electrode sheets 260 and the lengths in the protruding direction are appropriately adjusted in consideration of the state in which the positive electrode sheet group 250 is connected to the positive electrode collector 420. In addition, the shape of the positive electrode sheet 260 is not limited to Fig.12 The shape illustrated in . The positive electrode protection layer 243 is provided at the root of each of the plurality of positive electrode sheets 260. The positive electrode protection layer 243 does not necessarily need to be provided at the root of the positive electrode sheet 260. In a typical example, the thickness of the negative electrode sheet 230 (one sheet) is smaller than the thickness of the positive electrode sheet 260 (one sheet). In this case, the thickness of the negative electrode sheet group 220 is smaller than the thickness of the positive electrode sheet group 250. (Connection Structure of Electrode Body 200 and Current Collector 400) Fig.13 FIG. 2 is a diagram showing an electrode body 200 and a current collector 400 taken out of a secondary battery 1. Fig.13 As shown in FIG. 1 , the electrode body 200 is formed by stacking two electrode bodies 201 and 202, each of which is a wound electrode body. Fig.13 In the example shown, a structure in which two wound electrode bodies are stacked is shown, but the electrode body 200 may be composed of one wound electrode body, three or more wound electrode bodies, or a stacked electrode body. The negative electrode sheet group 220 is joined to the negative electrode current collector 410 at a joining portion 434 , and the positive electrode sheet group 250 is joined to the positive electrode current collector 420 at a joining portion 454 . Fig.14 It is a front view of the connection structure between the negative electrode sheet group and the negative electrode collector. Fig.15 It is a cross-sectional view of the connection structure between the negative electrode sheet group and the negative electrode current collector. like Fig.14 and Fig.15 As shown, the negative electrode current collector 410 electrically connects the negative electrode terminal 301 and the negative electrode sheet group 220. The negative electrode current collector 410 in this embodiment is connected to the negative electrode terminal 301 between the electrode body 200 and the first sealing plate 120. The negative electrode current collector 410 includes a first conductive member 430 and a second conductive member 440. The first conductive member 430 and the second conductive member 440 are joined at a joining portion 433. The first conductive member 430 and the second conductive member 440 are joined by, for example, laser welding. The first conductive member 430 is bonded to the negative electrode sheet group 220 at a bonding portion 434. The bonding portion 434 can be formed, for example, by ultrasonic welding, resistance welding, laser welding, riveting, etc. In this embodiment, the first conductive member 430 and the negative electrode sheet group 220 are bonded, for example, by ultrasonic bonding. The second conductive member 440 is connected to the negative terminal 301 at a joint portion 441. The joint portion 441 can be formed, for example, by ultrasonic welding, resistance welding, laser welding, riveting, etc. In the present embodiment, the negative terminal 301 and the second conductive member 440 are joined, for example, by providing a through hole in the second conductive member 440, inserting the negative terminal 301 into the through hole, riveting the negative terminal 301 to the second conductive member 440, and then welding the riveted portion and the second conductive member 440. The first conductive member 430 includes a first planar portion 431 and a second planar portion 432. The first planar portion 431 is connected to the second conductive member 440. The second planar portion 432 is connected to the negative electrode sheet group 220. The second planar portion 432 is disposed along the first sealing plate 120. A step portion 435 is provided between the first plane portion 431 and the second plane portion 432. With respect to the step portion 435, the first plane portion 431 and the second plane portion 432 are positioned differently in the first direction (X direction) when the secondary battery 1 is assembled. Thus, the first plane portion 431 and the second plane portion 432 can be arranged in one direction. The step portion 435 extends along the third direction (Z direction). A first insulating member 510 (resin member) is disposed between the negative electrode terminal 301 and the first sealing plate 120. A second insulating member 520 (resin member) is disposed between the first sealing plate 120 and the first conductive member 430 and the second conductive member 440. In addition, the first insulating member 510 and the second insulating member 520 may be an integral member. The negative electrode terminal 301 is attached to the first sealing plate 120 via the first insulating member 510 . The negative electrode terminal 301 is exposed outside the first sealing plate 120 and reaches the second conductive member 440 of the negative electrode collector 410 provided on the inner surface of the first sealing plate 120 . As the assembly order of each component, first, the negative electrode terminal 301 and the second conductive component 440 are mounted on the first sealing plate 120 together with the first insulating component 510 and the second insulating component 520. Next, the first conductive component 430 electrically connected to the electrode body 200 is mounted on the second conductive component 440. At this time, the first conductive component 430 is arranged on the first insulating component 510 in such a manner that a part of the first conductive component 430 overlaps with the second conductive component 440. Next, the first conductive component 430 and the second conductive component 440 are welded and connected at the joint 434. The negative electrode terminal 301 may be electrically connected to the first sealing plate 120 . In addition, the first sealing plate 120 may also play the role of the negative electrode terminal 301 . In addition, Fig.14 and Fig.15 In FIG. 4 , the negative electrode current collector 410 is exemplified as being composed of two members (the first conductive member 430 and the second conductive member 440 ), but the negative electrode current collector 410 may be composed of a single member. exist Fig.14 and Fig.15 , the connection structure on the negative electrode side is shown, but the basic connection structure on the positive electrode side is also the same as that on the negative electrode side. (Step of Inserting Electrode Body 200) Fig.16 2 is a diagram showing the process of inserting the electrode body 200 into the case body 110. Fig.16 As shown, a resin insulating sheet 700 (electrode body holder) is arranged between the electrode body 200 and the case body 110 . The insulating sheet 700 may be made of, for example, resin. More specifically, the insulating sheet 700 may be made of, for example, polypropylene (PP), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyimide (PI), or polyolefin (PO). The insulating sheet 700 does not necessarily need to cover the entire surface of the electrode body 200. The insulating sheet 700 preferably covers 50% or more of the outer surface of the electrode body, and more preferably covers 70% or more of the area. The insulating sheet 700 preferably covers the entirety of four of the six surfaces of the substantially rectangular parallelepiped (flat) electrode body 200, except for at least two surfaces each having the negative electrode sheet group 220 and the positive electrode sheet group 250 formed thereon. Fig.17 This is a diagram showing a step of placing the first separator 600 between the first sealing plate 120 and the electrode body 200 . like Fig.17 As shown, the negative electrode sheet group 220 arranged from the electrode body 200 toward the first sealing plate 120 is bent from the center of the first sealing plate 120 in the Y direction toward the end, and then folded back toward the center. The first separator 600 is provided in a manner to accommodate the bent portion of the negative electrode sheet group 220. The first separator 600 is arranged between the electrode body 200 and the first sealing plate 120. The first spacer 600 includes a first component 610 and a second component 620. The first component 610 and the second component 620 are respectively slid along the Y direction from the end side toward the center side of the first sealing plate 120 and are engaged with each other through the engaging parts 630A and 630B. Thus, the first spacer 600 is fixed to the first sealing plate 120 via the second insulating component 520, so that the position stability of the first spacer 600 is increased. The secondary battery 1 according to this embodiment includes a second separator (not shown). The second separator is disposed between the electrode assembly and the second sealing plate. The second separator may have the same structure as the first separator 600. In addition, the first separator 600 and the second separator may have different shapes. (Manufacturing of Housing Body 110) Fig.18 110A is a diagram showing a plate-shaped member constituting the housing body 110 . Fig.19 It is a figure which shows the state after the plate-shaped member 110A is bent. like Fig.18 As shown in FIG. 1 , the plate-like member 110A is bent along the bent portion 110B. Fig.19As shown, the plate-like member 110A is formed into a cylindrical shape having a pair of second side portions 112. Here, the portion where two end sides 110C parallel to the bent portion 110B are butted together constitutes a joint portion 115. Alternatively, the vicinity of the two end sides 110C may be overlapped with each other in the thickness direction of the plate-like member 110A and joined. The exhaust valve 150 is provided on the upper surface portion 112A of the pair of second side portions 112, and the joint portion 115 is provided on the bottom surface portion 112B. The exhaust valve 150 is composed of a thin-walled portion or a groove portion provided on the upper surface portion 112A of the housing body 110. The exhaust valve 150 can be formed by stamping or cutting. The exhaust valve 150 is preferably formed by stamping. When the exhaust valve 150 is formed by stamping, the shape of the thin-walled portion or the groove portion is stable, so that a more stable cracking strength of the exhaust valve 150 can be obtained. In addition, the exhaust valve can be provided in the housing body by joining a component including a portion that becomes the exhaust valve to the housing body. For example, the component including a portion that becomes the exhaust valve can be arranged in a manner such that a through hole is provided in the housing body and the through hole is blocked, and the component can be joined to the housing body by welding or the like. The exhaust valve 150 can be Fig.18 The plate-like member 110A shown in the figure is formed in the state (flat state before bending), and can also be formed in Fig.19 The plate-shaped member 110A may be formed in the state shown (the bent cylindrical state), and part or all of the processing may be performed simultaneously with the bending processing of the plate-shaped member 110A. When the exhaust valve 150 is formed in the state of the plate-shaped member 110A before the bending process, it is possible to more effectively suppress the case body 110 from being deformed due to strain in the process of forming the exhaust valve 150 . Furthermore, when the exhaust valve 150 is formed in a state after the bending process, deformation of the exhaust valve 150 due to the bending process can be effectively suppressed. (Structure of Insulation Sheet 700) Fig. 20 This is a diagram showing an example of the arrangement of the electrode body 200 and the insulating sheet 700 inside the case body 110 . like Fig. 20 As shown, the insulating sheet 700 is provided to cover the outer periphery of the electrode body 200. In addition, the insulating sheet 700 may expose a part of the electrode body 200. The insulating sheet includes a first end side 701 and a second end side 702 extending along the X direction. Here, one end side of one insulating sheet 700 is the first end side 701, and the other end side of one insulating sheet 700 is the second end side 702. Fig. 20In the illustrated example, the first end side 701 and the second end side 702 are arranged at positions facing the upper surface portion 112A of the case body 110. Between the first end side 701 and the second end side 702, an overlapping region 710 is provided where the insulating sheets 700 are overlapped in two layers. By disposing the first end side 701 and the second end side 702 of the insulating sheet 700 to face the upper surface portion 112A provided with the exhaust valve 150 , the gas generated in the electrode assembly 200 can easily move toward the exhaust valve 150 from the gap in the overlapping region 710 . The insulating sheet 700 is preferably not completely bonded or welded in the overlapping region 710. In this way, the above-mentioned gas exhaust path can be stably formed. By bonding or welding the overlapped insulating sheets 700 at a plurality of positions separated from each other in the overlapping region 710, the cylindrical shape of the insulating sheet 700 can be stably maintained. Fig.21 700 is an expanded view of the insulating sheet. Fig.21 As shown, the insulating sheet 700 is formed into a cylindrical shape by bending a sheet 700A along a bent portion 700B. Fig. 22 FIG. 2 is a front view showing the electrode body 200 and the insulating sheet 700. Fig. 22 As shown, the insulating sheet 700 is preferably provided to cover the entire body 270 (the portion other than the negative electrode sheet group 220 and the positive electrode sheet group 250) of the electrode body 200 and the root portion of the negative electrode sheet group 220 and the positive electrode sheet group 250. That is, the width of the insulating sheet 700 in the X direction is greater than the width of the body 270 of the electrode body 200 in the X direction. In this way, damage to the electrode body 200 can be more effectively suppressed. Fig. 20 As shown, by arranging the overlapping area 710 of the insulating sheet 700 on the exhaust valve 150 side, the gas escape from the inner peripheral side of the insulating sheet 700 toward the exhaust valve 150 can be improved, so that the exhaust valve 150 can work more stably. Fig.23 FIG. 1 is a diagram showing a modified example of the arrangement of the electrode bodies and the insulating sheets inside the case body 110. Fig.23 In the illustrated example, the overlapping region 710 of the insulating sheet 700 is provided in a region that does not overlap with the exhaust valve 150 when viewed from the Z direction (a region shifted in the Y direction). exist Fig.23In the example shown, the opening of the overlap region 710 is close to the exhaust valve 150, and the gas exhaust path from the inner peripheral side of the insulating sheet 700 to the exhaust valve 150 is further shortened. In addition, the overlap region 710 is not formed directly below the exhaust valve 150. In this way, the gas escape property toward the exhaust valve 150 can be further improved. However, the structure of the insulating sheet 700 is not limited to Figure 20 to Figure 23 In addition, the insulating sheet 700 is not necessarily an essential structure in the present technology. (Configuration of Exhaust Valve 150) Fig.24 2 is a diagram showing the upper portion of the electrode body 200. Fig.24 As shown, the two electrode bodies 201 and 202 included in the electrode body 200 are both wound electrode bodies. The electrode bodies 201 and 202 are adjacent to each other. The electrode body 201 (first electrode body) includes a curved surface 201A (first curved surface) facing the upper surface portion 112A of the shell body 110, and the electrode body 202 (second electrode body) includes a curved surface 202A (second curved surface) facing the upper surface portion 112A of the shell body 110. like Fig.24 As shown in FIG. 1 , when viewed from the X direction, the curved surfaces 201A and 202A respectively have a first vertex A1 and a second vertex A2 closest to the upper surface portion 112A. The first vertex A1 and the second vertex A2 are separated by a distance D1 in the Y direction. Here, when the area between the first vertex A1 and the second vertex A2 is defined as "area A", it is preferred that at least a portion of the exhaust valve 150 (more preferably a portion that becomes a starting point of cracking) is arranged in the area A. It is preferred that when viewed from the Z direction, more than 50 percent, more preferably more than 70 percent, of the area of ​​the exhaust valve 150 is arranged in the area A. More preferably, if Fig.24 As shown, when the area obtained by shifting the first vertex A1 and the second vertex A2 inward by D1 / 6 respectively is set as "area B", at least a portion of the exhaust valve 150 (more preferably the portion that becomes the starting point of cracking) is arranged in area B, and when observed from the Z direction, more than 50 percent, more preferably more than 70 percent, of the area of ​​the exhaust valve 150 is arranged in area B. Figure 25 to Figure 33 FIG. 1 is a diagram showing an example of the arrangement of the exhaust valve 150 in the upper surface portion 112A of the housing body 110. Figure 25 to Figure 33 In FIG. 1 , the two-dot chain line corresponds to the diagonal line of the rectangular upper surface portion 112A. The length ratio of the short side to the long side of the rectangular upper surface portion 112A on which the exhaust valve 150 is provided is preferably about 1:6 to 1:30. exist Fig.25In the example shown, the exhaust valve 150 includes a first portion 151 extending in the X direction (longitudinal direction) and a second portion 152 extending in the Y direction (shortitudinal direction). The first portion 151 and the second portion 152 intersect at the center of the upper surface portion 112A (intersection point of the diagonal lines). When the length of the housing body 110 in the X direction is L1 and the length of the first portion 151 of the exhaust valve 150 is L2, L2 / L1 is preferably larger than 0.5, and more preferably larger than 0.6. In this way, since a relatively large opening area of ​​the exhaust valve 150 can be ensured, gas can be exhausted more effectively when the exhaust valve 150 is broken. In addition, it is preferable that when the exhaust valve 150 is opened, the crack is generated over a length of 2 / 3L1 or more. Furthermore, by further providing the second portion 152 intersecting (orthogonal to) the first portion 151 , the second portion 152 can be broken in addition to the first portion 151 , so that the opening area of ​​the exhaust valve 150 can be further increased. The remaining wall thickness of the groove portion (thin-walled portion) constituting the exhaust valve 150 can be varied depending on the position. For example, around the intersection of the first portion 151 and the second portion 152, the remaining wall thickness can be made relatively thin (the groove can be formed to be deep). On the diagonal line of the upper surface portion 112A, a relatively large stress is generated when the internal pressure of the housing 100 rises, and a relatively large deformation occurs in this portion. By arranging the portion with a relatively thin remaining wall thickness on the diagonal line of the upper surface portion 112A, the portion with a large deformation (large stress) can be made thinner, that is, the stress concentration portion is made consistent with the strength-weak portion, thereby stabilizing the fracture position and fracture strength of the exhaust valve 150. As a result, the operating pressure of the exhaust valve 150 can be stabilized, thereby improving the reliability of the exhaust valve 150. exist Fig.26 , Fig. 27 In the example shown, the exhaust valve 150 includes a first portion 151 extending in the X direction (longitudinal direction) and two second portions 152 disposed apart from each other. Fig.26 , Fig. 27 In the example, the two second portions 152 are connected to the first portion 151 at both ends of the first portion 151 in the X direction, but the second portion 152 may be connected to a portion other than the two ends of the first portion 151 in the X direction. Fig.26 , Fig. 27 The shape illustrated in . exist Fig.28 In the illustrated example, the exhaust valves 150 are arranged in a substantially X-shape along the diagonal lines of the upper surface portion 112A. exist Fig.29In the example shown, the exhaust valve 150 includes a first portion 151 extending along the Y direction (short-side direction) and two second portions 152 extending along the X direction (long-side direction). Fig.29 In the example, the two second portions 152 are connected to the first portion 151 at both ends of the first portion 151 in the Y direction, but the second portions 152 may be connected to portions other than the both ends of the first portion 151 in the Y direction. exist Figure 30 to Figure 33 In the example shown, the exhaust valve 150 is divided into a plurality of regions separated from each other. Figure 30 to Figure 33 In the example of FIG. 1 , two separate exhaust valves 150 are arranged to reach the ends of the upper surface portion 112A in the X direction, respectively. The exhaust valves may be arranged separately in three or more regions. exist Fig.30 In the example, the two exhaust valves 150 are formed in a linear shape so as to extend along the X direction (longitudinal direction). Fig.31 , Fig.33 In the example of , the two exhaust valves 150 are each formed in a substantially cross shape. Fig.32 In the example, the two exhaust valves 150 are each formed in a substantially U-shape so as to open toward the end side in the X direction. exist Fig.33 In the example of FIG. 1 , the exhaust valve 150 is arranged inside the recessed portion 160 (thin-walled region) formed in the upper surface portion 112A. Fig.34 yes Fig.33 The XXXIV-XXXIV section view in FIG. Fig.34 As shown, since the recess 160 is formed in such a way that the thickness of the housing body 110 is relatively small, the deformation amount when the internal pressure of the housing 100 increases is relatively large. Therefore, by forming the exhaust valve 150 in the recess 160, the exhaust valve 150 can operate more stably when the internal pressure of the housing 100 increases. The length of each exhaust valve 150 is preferably the length L1 ( Fig.25 ) is at least 1 / 15 of the original amount, more preferably at least 1 / 8 of the original amount, and even more preferably at least 1 / 5 of the original amount. The arrangement of the exhaust valve 150 is not limited to Figure 25 to Figure 34 Alternatively, you can also Figure 25 to Figure 34 The methods shown in the examples can be used in combination. Fig.35 1 is an enlarged cross-sectional view showing an example of a groove portion constituting the exhaust valve 150. Fig.35 As shown in FIG. 1 , the groove constituting the exhaust valve 150 is formed on the outer surface of the housing body 110 . However, the groove may be formed on the inner surface of the housing body 110 . By forming the groove that constitutes the exhaust valve 150 on the outer surface of the case body 110, it is possible to suppress the electrode body 200 from being caught on the groove (interference) when the electrode body 200 is inserted into the case body 110. On the other hand, when the groove is formed on the inner surface of the case body 110, after the electrode body 200 is inserted into the case body 110 and sealed by the first sealing plate 120 and the second sealing plate 130, the surface of the groove is protected, so that the operating pressure of the exhaust valve 150 can be further stabilized. exist Fig.35 In the example shown, the exhaust valve 150 is formed by a substantially V-shaped groove. In one example, the substantially V-shaped opening angle θ is about 60° or more and 90° or less. However, the shape of the groove forming the exhaust valve 150 is not limited to Fig.35 In the shape shown, for example, the exhaust valve 150 may be formed of a groove portion having a substantially rectangular cross-sectional shape. Fig.36 It is a diagram for explaining the arrangement of the exhaust valve 150 in the X direction (first direction). like Fig.36 As shown, the electrode body 200 includes a main body 270 , and a negative electrode sheet group 220 and a positive electrode sheet group 250 protruding from the main body 270 toward the first sealing plate 120 and the second sealing plate 130 , respectively. The upper surface portion 112A of the case body 110 includes a region R270 facing the main body 270 of the electrode body 200, an end region R120 located closer to the first sealing plate 120 than the main body 270, and an end region R130 located closer to the second sealing plate 130 than the main body 270. At least a portion of the exhaust valve 150 is arranged to reach the end regions R120 and R130. In one example, the lengths of the end regions R120 and R130 in the X direction are respectively about 12 mm±1 mm. The lengths of the end regions R120 and R130 are, for example, about 1 / 5 or less of the length L1 of the case body 110 . The exhaust valve 150 is formed to extend from the boundary between the region R270 and the end regions R120 and R130 to a position moved outward (toward the first sealing plate 120 and the second sealing plate 130 ) by at least 50 percent of the length of the end regions R120 and R130 . In this way, by configuring the exhaust valve 150 in a manner that reaches the end areas R120 and R130 located at both ends in the X direction, when the internal pressure of the shell 100 rises, the gas can flow to the exhaust valve 150 through the gaps on the negative electrode sheet group 220 and the positive electrode sheet group 250, so that the exhaust valve 150 can be broken more smoothly and the gas can be discharged. (Function and Effect) According to the secondary battery 1 of this embodiment, by forming a structure in which the electrode body 200 is inserted into the shell body 110 having the first opening portion 113 and the second opening portion 114 facing each other, and the first opening portion 113 and the second opening portion 114 are sealed respectively, the height of the secondary battery 1 can be reduced, thereby becoming a secondary battery 1 with high capacity and high mountability in a vehicle. In addition, by providing an exhaust valve 150 on the upper surface portion 112A of the shell body 110 and providing a joint portion 115 on the bottom portion 112B opposite to the upper surface portion 112A, the exhaust valve 150 and the joint portion 115 can be separated to different sides of the shell body 110, thereby stabilizing the working pressure of the exhaust valve 150. As a result, a secondary battery 1 with high capacity and high reliability can be provided. Furthermore, the exhaust valve 150 may be provided on the bottom surface portion 112B of the housing body 110 , and the joint portion 115 may be provided on the upper surface portion 112A facing the bottom surface portion 112B. In addition, if Fig. 20 and Fig.23 As shown, by making the overlapping region 710 of the insulating sheet 700 face the upper surface portion 112A provided with the exhaust valve 150 , the gas generated inside the electrode body 200 can flow smoothly toward the exhaust valve 150 . In addition, if Fig.24 As shown, by disposing at least a portion of the exhaust valve 150 in the region A or region B between the first vertex A1 and the second vertex A2 of the plurality of electrode bodies 201 and 202 adjacent to each other, the gas generated inside the electrode body 200 can flow smoothly toward the exhaust valve 150. Therefore, the operating pressure of the exhaust valve 150 can be further stabilized. In the present embodiment, an example is described in which the centers of the negative electrode sheet group 220 and the positive electrode sheet group 250 are arranged near the center of the electrode body 200 in the Z direction, but the centers of the negative electrode sheet group 220 and the positive electrode sheet group 250 may be arranged at a position shifted to the opposite side of the exhaust valve 150 (upper surface portion 112A), that is, the lower side (bottom surface portion 112B side) in the Z direction. In this case, it is easier to ensure the exhaust path of the gas reaching the exhaust valve 150. exist Figure 2In the example, the joint 115 is provided at the center of the bottom portion 112B in the Y direction. The joint 115 can be arranged in a position deviated from the center of the bottom portion 112B to any end side (any side of the two long end sides of the bottom portion 112B) in the Y direction. In this case, even if the internal pressure in the housing 100 rises, damage to the joint 115 can be more reliably suppressed by offsetting the joint 115 from the portion where stress is easily concentrated. Therefore, the exhaust valve 150 operates more stably. It is particularly preferred that the portion of the joint 115 located at the center of the bottom portion 112B in the X direction has such a structure. Although the embodiments of the present invention have been described, the embodiments disclosed this time should be considered to be illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the claims, and it is intended to include all changes within the meaning and scope equivalent to the claims.

Claims

1. A secondary battery, characterized in that: have: an electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode; and a shell that accommodates the electrode body, The housing comprises: a housing body having a first opening located at an end portion on a first side in a first direction, and a second opening located at an end portion on a second side opposite to the first side in the first direction; a first sealing plate for sealing the first opening; as well as a second sealing plate for sealing the second opening, The shell body includes a pair of first walls facing each other in a second direction orthogonal to the first direction, and a pair of second walls facing each other in a third direction orthogonal to the first direction and the second direction, and an area of ​​the pair of first walls is larger than an area of ​​the pair of second walls. A gas exhaust valve is provided on one of the pair of second walls, which is broken when the pressure in the housing becomes equal to or higher than a predetermined value. The other of the pair of second walls is provided with a joining portion extending along the first direction.

2. The secondary battery according to claim 1, characterized in that: The exhaust valve includes a thin-walled portion or a groove portion formed in one of the pair of second walls.

3. The secondary battery according to claim 1 or 2, characterized in that: The electrode body comprises: Main body; a first electrode sheet electrically connected to the first electrode and located on the first side relative to the main body; and a second electrode sheet electrically connected to the second electrode and located on the second side relative to the main body; The first electrode sheet is electrically connected to a first electrode terminal provided on the first sealing plate. The second electrode sheet is electrically connected to a second electrode terminal provided on the second sealing plate.

4. The secondary battery according to claim 1 or 2, characterized in that: The electrode body comprises: Main body; a first electrode sheet electrically connected to the first electrode and located on the first side relative to the main body; and a second electrode sheet electrically connected to the second electrode and located on the second side relative to the main body; At least a portion of the exhaust valve is disposed in a first end region closer to the first opening than the main body of the electrode body in the first direction. At least a portion of the exhaust valve is disposed in a second end region closer to the second opening than the main body of the electrode body in the first direction.

5. The secondary battery according to claim 1 or 2, characterized in that: The electrode body includes a first electrode body and a second electrode body, and the first electrode body and the second electrode body are respectively wound electrode bodies. The first electrode body is arranged adjacent to the second electrode body. The first electrode body includes a first curved surface facing one of the pair of second walls, the first curved surface having a first vertex closest to one of the pair of second walls, The second electrode body includes a second curved surface facing one of the pair of second walls, the second curved surface having a second vertex closest to one of the pair of second walls, At least a portion of the exhaust valve is arranged in a region between the first vertex and the second vertex in the second direction.

6. The secondary battery according to claim 1 or 2, characterized in that: The secondary battery further comprises an insulating sheet covering at least a portion of the outer periphery of the electrode body. The insulating sheet includes a first end side and a second end side extending along the first direction, The first end side and the second end side are arranged at positions facing one of the pair of second walls. A region where the insulating sheets are overlapped in two layers is provided between the first end side and the second end side.

7. The secondary battery according to claim 1 or 2, characterized in that: The exhaust valves are arranged in a plurality of regions separated from each other on one of the pair of second walls.

8. The secondary battery according to claim 1 or 2, characterized in that: A thin-walled region of the housing body having a relatively small thickness is formed on one of the pair of second walls. The exhaust valve is disposed inside the thin-walled region.

9. The secondary battery according to claim 1 or 2, characterized in that: In the second direction, the joining portion is arranged at a position offset from the center of the other of the pair of second walls toward an arbitrary end portion.

Images