Battery

Abstract

To prevent occurrence of partial discharge between an electrode body and an outer packaging body.SOLUTION: An insulation sheet 50 includes a bottom surface part 500, a first lateral surface part 510, a second lateral surface part 511, a first left piece part 520, a second left piece part 521, a left bottom piece part 522, a first left connection part 523, and a second left connection part 524. On the insulation sheet 50, the first left piece part 520, the second left piece part 521, the left bottom piece part 522, the first left connection part 523, and the second left connection part 524 form a first communication path 530 which has a first opening end 531 at a position on the ends of the first left connection part 523 and the second left connection part 524 on an opening part 101 side of an outer packaging body 100, thereby bringing the inside of the insulation sheet 50 into communication with the outside thereof. The first communication path 530 is located on the shortest infiltration route for an electrolyte 80 which infiltrates from the outside of the insulation sheet 50 to an end part 20e of an electrode body 20 located on a bottom part 102 side of the outer packaging body 100 and closest to a ridge line part of one of a pair of second lateral walls 104a, 104b.SELECTED DRAWING: Figure 18

Description

[Technical Field]

[0001] The present technology relates to batteries. [Background technology]

[0002] A prior document disclosing the configuration of an electricity storage device is Japanese Patent Application Laid-Open No. 2019-29218 (Patent Document 1). The electricity storage device described in Patent Document 1 includes an electrode assembly, an insulating holder, and an outer case. The insulating holder houses the electrode assembly. The outer case houses the electrode assembly together with the insulating holder and an electrolyte. The insulating holder is formed by folding an insulating sheet. The insulating sheet is composed of multiple sheet elements separated by multiple folds and multiple cuts. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-29218 Summary of the Invention [Problem to be solved by the invention]

[0004] If a short circuit path is formed between batteries located at both ends of multiple batteries connected in series due to flooding around the batteries, etc., a high voltage will be applied between the electrode body and the outer casing inside the battery located on the short circuit path, and insulation between the electrode body and the outer casing may be broken down through the gap between the electrode body and the outer casing formed by the cut in the insulating sheet, causing partial discharge.

[0005] The present technology has been made to solve the above-mentioned problems, and aims to provide a battery that can suppress the occurrence of partial discharge between an electrode body and an outer casing. [Means for solving the problem]

[0006] a positive electrode terminal electrically connected to the positive electrode plate and attached to the sealing plate; a negative electrode terminal electrically connected to the negative electrode plate and attached to the sealing plate; and an insulating sheet disposed between the electrode body and the exterior body; and the exterior body has a bottom facing the opening, a pair of first side walls standing upright from the edge of the bottom and facing each other, and a pair of second side walls standing upright from the edge of the bottom and facing each other. the insulating sheet has a bottom surface portion facing the bottom portion, a first side surface portion disposed between one of the pair of first side walls and the electrode body, a second side surface portion disposed between the other of the pair of first side walls and the electrode body, a first left side piece bent from one lateral end of the first side surface portion and disposed between one of the pair of second side walls and the electrode body, and a second left side piece bent from one lateral end of the second side surface portion and disposed between one of the pair of second side walls and the electrode body. a second left side piece that is arranged so as to overlap at least a portion of the first left side piece; a left side bottom piece that rises from one end of the side of the bottom surface portion and is located between one of the pair of second side walls and the electrode body; a first left side connection portion that is provided continuously with each of the first left side piece and the left side bottom piece and is bent at the boundary between each of the first left side piece and the left side bottom piece and is sandwiched between the first left side piece and the left side bottom piece; and a second left-side connecting portion bent at the boundary with each of the left-side pieces and sandwiched between the second left-side piece and the left-side bottom piece, and the shortest infiltration path of the electrolyte solution infiltrating from outside the insulating sheet into the end of the electrode body that is closest to the ridge line portion on the bottom side of the exterior body and one of the pair of second side walls is a path that passes through any one of the outer circumferential edge of the first left-side connecting portion, the outer circumferential edge of the left-side bottom piece, and the outer circumferential edge of the second left-side connecting portion,the shortest distance between the portion on the shortest penetration path and the bottom is 5 mm or more, and the electrode assembly further includes a tab portion provided on at least one of the positive electrode plate and the negative electrode plate and extending to a side of the electrode body, and a current collector connected to the tab portion, the current collector including a first region facing the second side wall, a third region located closer to the sealing plate than the first region and facing the second side wall, and a second region connecting the first region and the third region, and the current collector and the second side wall facing each other have a shortest distance between the first region and the second side wall in a direction perpendicular to the second side wall that is shorter than the shortest distance between the third region and the second side wall. [Effects of the Invention]

[0007] According to the present technology, it is possible to suppress the occurrence of partial discharge between the electrode body and the outer casing. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view showing a configuration of a battery according to a first embodiment of the present technology. [Figure 2] 2 is a cross-sectional view of the battery of FIG. 1 as seen from the direction of the arrows along line II-II. [Figure 3] 1 is a perspective view showing the internal configuration of a battery according to a first embodiment of the present technology, excluding an exterior body and an insulating sheet included in the battery. [Figure 4] 1 is a front view showing a positive electrode original plate before being formed into a positive electrode plate included in a battery according to a first embodiment of the present technology. [Figure 5] 5 is a cross-sectional view of the positive electrode plate of FIG. 4 as viewed from the direction of the arrows VV line. [Figure 6] 1 is a front view showing a state after a positive electrode plate included in a battery according to a first embodiment of the present technology has been formed. [Figure 7] 1 is a front view showing a negative electrode original plate before being formed into a negative electrode plate included in a battery according to a first embodiment of the present technology. [Figure 8] 8 is a cross-sectional view of the negative electrode plate of FIG. 7, seen from the direction of the arrows along line VIII-VIII. [Figure 9]1 is a front view showing a state after a negative electrode plate included in a battery according to a first embodiment of the present technology has been formed. [Figure 10] 1 is a perspective view showing the configuration of an electrode assembly and a current collector included in a battery according to a first embodiment of the present technology. [Figure 11] 11 is a cross-sectional view of the electrode body and current collector of FIG. 10, taken along the line XI-XI. [Figure 12] 3 is a cross-sectional view showing a state in which a tab portion of an electrode body included in a battery according to embodiment 1 of the present technology is bent. FIG. [Figure 13] 2 is a top perspective view showing a configuration of a part of a current collector and a sealing plate included in the battery according to the first embodiment of the present technology. FIG. [Figure 14] 2 is a bottom perspective view showing a configuration of a part of a current collector and a sealing plate included in the battery according to embodiment 1 of the present technology. FIG. [Figure 15] 3 is an enlarged cross-sectional view of the XV portion of the battery shown in FIG. 2. FIG. [Figure 16] 3 is an enlarged cross-sectional view of the XVI portion of the battery shown in FIG. 2. FIG. [Figure 17] 1 is a perspective view showing the positional relationship between a battery case and an insulating sheet included in a battery according to a first embodiment of the present technology. [Figure 18] 1 is a perspective view showing a configuration of a battery according to a first embodiment of the present technology, excluding an exterior body provided in the battery. [Figure 19] 19 is an enlarged perspective view of the battery shown in FIG. 18 at part XIX. [Figure 20] 1 is a development view showing a configuration of an insulating sheet included in a battery according to a first embodiment of the present technology. [Figure 21] 1 is a perspective view showing a state in which an insulating sheet included in a battery according to a first embodiment of the present technology is folded. [Figure 22] 20 is a side view of the battery of FIG. 18 as seen from the direction of arrow XXII. [Figure 23] 18 is a cross-sectional view of the battery of FIG. 17 as viewed from the direction of the arrows along line XXIII-XXIII. [Figure 24] 20 is a side view of the battery of FIG. 18 as seen from the direction of arrow XXIV. [Figure 25] 10 is a development view showing the configuration of an insulating sheet included in a battery according to a second embodiment of the present technology. FIG. [Figure 26] 10 is a side view showing the internal configuration of a battery according to a second embodiment of the present technology. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present technology will be described. Note that the same or corresponding parts are denoted by the same reference characters, and description thereof may not be repeated.

[0010] In the embodiments described below, when numbers, amounts, etc. are mentioned, unless otherwise specified, the scope of the present technology is not necessarily limited to those numbers, amounts, etc. Furthermore, in the embodiments described below, each component is not necessarily essential to the present technology unless otherwise specified.

[0011] In this specification, the terms "comprise," "include," and "have" are used in an open-ended manner. That is, when a certain configuration is included, other configurations may or may not be included. Furthermore, the present technology is not necessarily limited to those that achieve all of the effects and advantages described in the present embodiment.

[0012] In this specification, the term "battery" is not limited to lithium-ion batteries and may include other batteries such as nickel-metal hydride batteries. In this specification, the term "electrode" may collectively refer to positive and negative electrodes. Furthermore, the term "electrode plate" may collectively refer to positive and negative plates.

[0013] In this specification, the terms "storage cell" and "storage module" are not limited to battery cells and battery modules, but may include capacitor cells and capacitor modules.

[0014] (Embodiment 1) Fig. 1 is a perspective view showing a configuration of a battery according to a first embodiment of the present technology. Fig. 2 is a cross-sectional view of the battery in Fig. 1 as seen from the direction of the arrows along line II-II. Fig. 3 is a perspective view showing an internal configuration of the battery according to the first embodiment of the present technology, excluding an exterior body and an insulating sheet included in the battery.

[0015] 1 to 3, the battery 1 includes a battery case 10, an electrode assembly 20, a positive electrode current collector 30, a negative electrode current collector 40, an insulating sheet 50, a positive electrode external conductive member 60, and a negative electrode external conductive member 70. The battery case 10 includes an exterior body 100 and a sealing plate 110.

[0016] The exterior body 100 is a rectangular cylinder with a bottom and has an opening 101 into which the electrode assembly 20 can be inserted. The exterior body 100 contains the electrode assembly 20 and an electrolyte. The exterior body 100 is made of metal. Specifically, the exterior body 100 is made of aluminum, an aluminum alloy, iron, an iron alloy, or the like.

[0017] Exterior body 100 has a bottom 102, a pair of first side walls 103a and 103b, and a pair of second side walls 104a and 104b.

[0018] The bottom 102 faces the opening 101. A pair of first side walls 103a, 103b stand upright from the edge of the bottom 102 and face each other in parallel. A pair of second side walls 104a, 104b stand upright from the edge of the bottom 102 and face each other in parallel. Each of the pair of second side walls 104a, 104b connects the first side walls 103a, 103b to each other. The area of each of the pair of first side walls 103a, 103b is larger than the area of each of the pair of second side walls 104a, 104b.

[0019] Sealing plate 110 seals opening 101 of exterior body 100. Sealing plate 110 is made of, for example, aluminum, an aluminum alloy, iron, or an iron alloy.

[0020] The sealing plate 110 has an electrolyte injection hole 111. The electrolyte injection hole 111 is sealed with a sealing member 112. The sealing plate 110 has a gas release valve 113 that breaks when the pressure inside the battery case 10 reaches or exceeds a predetermined value, and releases gas inside the battery case 10 to the outside.

[0021] The electrode assembly 20 in this embodiment is a flat electrode assembly having a positive electrode plate and a negative electrode plate, which will be described later. Specifically, the electrode assembly 20 is a wound electrode assembly in which a strip-shaped positive electrode plate and a strip-shaped negative electrode plate are wound together with a strip-shaped separator (not shown) interposed therebetween.

[0022] As shown in FIGS. 2 and 3 , the battery case 10 houses an electrode assembly 20. Specifically, a plurality of wound electrode assemblies are housed inside an insulating sheet 50 arranged inside an exterior body 100 of the battery case 10, together with an electrolyte (not shown). The battery case 10 in this embodiment houses three wound electrode assemblies. The electrode assemblies 20 are housed inside the exterior body 100 with their winding axes oriented parallel to the bottom 102. The number of electrode assemblies 20 arranged inside the exterior body 100 is not limited to three. Furthermore, the electrode assemblies 20 are not limited to wound electrode assemblies, and may be stacked electrode assemblies in which a plurality of positive electrode plates and a plurality of negative electrode plates are alternately stacked.

[0023] In the electrode body 20, a tab portion 21 is provided on at least one of the positive electrode plate and the negative electrode plate, and extends to the side of the electrode body 20. In the electrode body 20 of this embodiment, a positive electrode tab group 210 including multiple positive electrode tabs is provided as one tab portion 21 at one end of the electrode body 20 in the direction in which the winding axis of the electrode body 20 extends. A negative electrode tab group 260 including multiple negative electrode tabs is provided as the other tab portion 21 at the other end of the electrode body 20 in the direction in which the winding axis of the electrode body 20 extends.

[0024] The electrode body 20 is preferably arranged in the outer casing 100 with the insulating sheet 50 sandwiched between them, with one second side wall 104a facing the positive electrode tab group 210 and the other second side wall 104b facing the negative electrode tab group 260.

[0025] As shown in FIGS. 1 to 3, a positive electrode terminal 230 and a negative electrode terminal 280 are attached to the sealing plate 110. Specifically, as shown in FIGS. 2 and 3, the positive electrode terminal 230 is electrically connected to the positive electrode tab group 210 in each of the plurality of electrode assemblies 20 via the positive electrode current collector 30. A positive electrode external conductive member 60 is connected to the positive electrode terminal 230. Note that the battery 1 does not necessarily have to include the positive electrode external conductive member 60.

[0026] Each of the positive electrode terminal 230 and the positive electrode external conductive member 60 is preferably made of metal, and more preferably made of aluminum or an aluminum alloy.

[0027] The negative electrode terminal 280 is electrically connected to the negative electrode tab group 260 in each of the plurality of electrode bodies 20 via the negative electrode current collector 40. A negative electrode external conductive member 70 is connected to the negative electrode terminal 280. Note that the battery 1 does not necessarily have to include the negative electrode external conductive member 70.

[0028] The negative electrode terminal 280 is preferably made of metal, more preferably copper or a copper alloy. The negative electrode external conductive member 70 is preferably made of metal, more preferably aluminum or an aluminum alloy. Note that the region of the negative electrode terminal 280 that is connected to the negative electrode current collector 40 may be made of copper or a copper alloy, and the region that protrudes outward from the sealing plate 110 may be made of aluminum or an aluminum alloy.

[0029] The positive electrode current collector 30 has a plate-like shape. The positive electrode current collector 30 is connected to one of the tab portions 21. In this embodiment, the positive electrode current collector 30 is connected to a positive electrode tab group 210. The positive electrode current collector 30 is preferably made of metal, and more preferably made of aluminum or an aluminum alloy.

[0030] The positive electrode current collector 30 in this embodiment includes a first positive electrode current collector 300 as an extended current collector and a second positive electrode current collector 310 as a current collector.

[0031] The first positive electrode current collector 300 is connected to the positive electrode terminal 230 between the electrode assembly 20 and the sealing plate 110. The first positive electrode current collector 300 is connected to the second positive electrode current collector 310 at the end opposite to the side where the positive electrode terminal 230 is connected. The second positive electrode current collector 310 is connected to the positive electrode tab group 210 at the end opposite to the side where it is connected to the first positive electrode current collector 300. The positive electrode current collector 30 may be composed of a single component.

[0032] The negative electrode current collector 40 has a plate shape. The negative electrode current collector 40 is connected to the other tab portion 21. In the present embodiment, the negative electrode current collector 40 is connected to a negative electrode tab group 260. The negative electrode current collector 40 is preferably made of metal, and more preferably made of copper or a copper alloy.

[0033] The negative electrode current collector 40 in this embodiment includes a first negative electrode current collector 400 as an extended current collector and a second negative electrode current collector 410 as a current collector. The first negative electrode current collector 400 is connected to the negative electrode terminal 280 between the electrode assembly 20 and the sealing plate 110. The first negative electrode current collector 400 is connected to the second negative electrode current collector 410 at an end opposite to the end to which the negative electrode terminal 280 is connected. The second negative electrode current collector 410 is connected to the negative electrode tab group 260 at an end opposite to the end connected to the first negative electrode current collector 400. The negative electrode current collector 40 may be composed of a single component.

[0034] As shown in Fig. 2, one insulating sheet 50 is disposed between the electrode assembly 20 and the exterior housing 100. The insulating sheet 50 is preferably a resin sheet. The material of the insulating sheet 50 is preferably polypropylene (PP), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyimide (PI), or polyolefin (PO), for example. PP is particularly preferred as the material of the insulating sheet 50.

[0035] The melting point of the insulating sheet 50 is preferably 100°C or higher and 400°C or lower, more preferably 120°C or higher and 300°C or lower, and particularly preferably 150°C or higher and 170°C or lower.

[0036] The thickness of the insulating sheet 50 is preferably 0.05 mm or more and 1 mm or less, more preferably 0.08 mm or more and 0.5 mm or less, and particularly preferably 0.1 mm or more and 0.2 mm or less.

[0037] Below, we will explain the details of each component of the battery 1 and the method for manufacturing the battery 1. First, we will explain the positive electrode plate.

[0038] Fig. 4 is a front view showing a positive electrode blank before the positive electrode plate included in the battery according to embodiment 1 of the present technology is formed. Fig. 5 is a cross-sectional view of the positive electrode blank in Fig. 4 as viewed from the direction of the VV line arrows. Fig. 6 is a front view showing a state after the positive electrode plate included in the battery according to embodiment 1 of the present technology has been formed.

[0039] The positive electrode plate is manufactured by processing a positive electrode substrate 200S. As shown in Figures 4 and 5, the positive electrode substrate 200S includes a positive electrode core 201, a positive electrode active material layer 202, and a positive electrode protective layer 203. The positive electrode core 201 is an aluminum foil or an aluminum alloy foil.

[0040] A positive electrode active material layer 202 is formed on both surfaces of the positive electrode core 201, except for one end portion. The positive electrode active material layer 202 is formed on the positive electrode core 201 by applying a positive electrode active material layer slurry using a die coater.

[0041] The positive electrode active material layer slurry is prepared by kneading lithium nickel cobalt manganese composite oxide as the positive electrode active material, polyvinylidene fluoride (PVdF) as a binder, a carbon material as a conductive material, and N-methyl-2-pyrrolidone (NMP) as a dispersion medium so that the mass ratio of lithium nickel cobalt manganese composite oxide:PVdF:carbon material is 97.5:1:1.5.

[0042] The positive electrode protective layer 203 is formed on one end of the positive electrode active material layer 202 in the width direction while being in contact with the positive electrode core 201. The positive electrode protective layer 203 is formed on the positive electrode core 201 by applying a positive electrode protective layer slurry using a die coater.

[0043] The positive electrode protective layer slurry is 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 is 83:3:14.

[0044] The positive electrode substrate 201 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. This forms the positive electrode active material layer 202 and the positive electrode protective layer 203. The positive electrode active material layer 202 is then compressed to form a positive electrode substrate 200S including the positive electrode substrate 201, the positive electrode active material layer 202, and the positive electrode protective layer 203. The positive electrode substrate 200S is cut into a predetermined shape to form a positive electrode plate. The positive electrode substrate 200S can be cut by laser processing using energy beam irradiation, mold processing, cutter processing, or the like.

[0045] 6, a plurality of positive electrode tabs 220 made of positive electrode core bodies 201 are provided at one end in the width direction of a positive electrode plate 200 formed from a positive electrode original plate 200S. The length or width in the protruding direction of the plurality of positive electrode tabs 220 is appropriately adjusted depending on the position at which each of the plurality of positive electrode tabs 220 is formed, taking into consideration the state in which the plurality of positive electrode tabs 220 are stacked and connected to a positive electrode current collector 30 as a positive electrode tab group 210.

[0046] A positive electrode protective layer 203 is provided at the base of each of the positive electrode tabs 220. The positive electrode tab group 210 does not necessarily have to be provided with the positive electrode protective layer 203.

[0047] Next, the negative electrode plate will be described. Fig. 7 is a front view showing a negative electrode blank before the negative electrode plate included in the battery according to embodiment 1 of the present technology is formed. Fig. 8 is a cross-sectional view of the negative electrode blank in Fig. 7 as viewed from the direction of the arrow VIII-VIII. Fig. 9 is a front view showing a state after the negative electrode plate included in the battery according to embodiment 1 of the present technology has been formed.

[0048] The negative electrode plate is manufactured by processing a negative electrode original plate 250S. As shown in Figures 7 and 8, the negative electrode original plate 250S includes a negative electrode core 251 and a negative electrode active material layer 252. The negative electrode core 251 is a copper foil or a copper alloy foil.

[0049] A negative electrode active material layer 252 is formed on both surfaces of the negative electrode substrate 251 except for one end portion. The negative electrode active material layer 252 is formed by applying a negative electrode active material layer slurry using a die coater.

[0050] The negative electrode active material layer slurry is prepared by kneading graphite as the 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 98:1:1.

[0051] The negative electrode substrate 251 coated with the negative electrode active material layer slurry is dried to remove water contained in the negative electrode active material layer slurry. This forms the negative electrode active material layer 252. The negative electrode active material layer 252 is then compressed to form a negative electrode base plate 250S including the negative electrode substrate 251 and the negative electrode active material layer 252. The negative electrode base plate 250S is cut into a predetermined shape to form the negative electrode plate 250. The negative electrode base plate 250S can be cut by laser processing using energy beam irradiation, mold processing, cutter processing, or the like.

[0052] 9, a plurality of negative electrode tabs 270 made of negative electrode core bodies 251 are provided at one end in the width direction of a negative electrode plate 250 formed from a negative electrode original plate 250S. The length or width in the protruding direction of the plurality of negative electrode tabs 270 is appropriately adjusted depending on the position at which each of the plurality of negative electrode tabs 270 is formed, taking into consideration the state in which the plurality of negative electrode tabs 270 are stacked and connected to a negative electrode current collector 40 as a negative electrode tab group 260.

[0053] Next, the electrode assembly 20, the positive electrode current collector 30, and the negative electrode current collector 40 will be described. Fig. 10 is a perspective view showing the configuration of the electrode assembly and current collectors included in the battery according to the first embodiment of the present technology. Fig. 10 shows the state before the tab portion 21 is folded.

[0054] As shown in FIG. 10, a strip-shaped positive electrode plate 200 and a strip-shaped negative electrode plate 250 prepared by the above-described method are wound with a strip-shaped separator (not shown) interposed therebetween to prepare a flat electrode assembly 20. The separator is preferably a polyolefin substrate with a heat-resistant layer provided on its surface. This heat-resistant layer contains ceramic particles and a binder. Examples of ceramic particles that can be used include aluminum oxide, boehmite, aluminum hydroxide, and titania.

[0055] A positive electrode tab group 210 including a plurality of positive electrode tabs 220 provided on the positive electrode plate 200 is arranged at one lateral end of the electrode body 20 in the direction in which the winding axis of the electrode body 20 extends.

[0056] The thickness of the positive electrode tab 220 is preferably 5 μm or more and 30 μm or less, and more preferably 8 μm or more and 20 μm or less. The number of stacked positive electrode tabs 220 in the positive electrode tab group 210 is preferably 10 or more, more preferably 20 or more, and particularly preferably 30 or more.

[0057] A negative electrode tab group 260 including a plurality of negative electrode tabs 270 provided on the negative electrode plate 250 is disposed at the other lateral end of the electrode body 20 in the direction in which the winding axis of the electrode body 20 extends. In this manner, the tab section 21 is composed of at least one of the positive electrode tab group 210 and the negative electrode tab group 260. The tab section 21 in this embodiment is composed of the positive electrode tab group 210 and the negative electrode tab group 260.

[0058] The thickness of the negative electrode tab 270 is preferably 5 μm or more and 30 μm or less, and more preferably 8 μm or more and 20 μm or less. The number of stacked negative electrode tabs 270 in the negative electrode tab group 260 is preferably 10 or more, more preferably 20 or more, and particularly preferably 30 or more.

[0059] The second positive electrode current collector 310 has a first region 311, a second region 312, and a third region 313. As shown in Fig. 2, the first region 311 faces one of the second side walls 104a. The tab portion 21 is connected to the first region 311.

[0060] 2 and 10, the second region 312 is located on the sealing plate 110 side of the first region 311. The second region 312 is inclined with respect to both the first region 311 and the third region 313.

[0061] The third region 313 is located on the sealing plate 110 side of the second region 312 and faces one of the second side walls 104a. The third region 313 is connected to the first positive electrode current collector 300.

[0062] 2, the first region 311 and the third region 313 are arranged so that their flat surfaces are approximately perpendicular to the winding axis of the electrode body 20. In the second positive electrode current collector 310 and one of the second side walls 104a that face each other, the shortest distance between the first region 311 and one of the second side walls 104a in a direction perpendicular to the one of the second side walls 104a is shorter than the shortest distance between the third region 313 and one of the second side walls 104a.

[0063] 10, a recess 314 is provided in the third region 313. The portion where the recess 314 is provided is thinner than the surrounding area. A through-hole 315 is provided in the recess 314. The third region 313 is joined to the first positive electrode current collector 300 at the recess 314. A fuse hole 316 can be provided in the second positive electrode current collector 310.

[0064] Similar to the second positive electrode current collector 310, the second negative electrode current collector 410 has a first region 411, a second region 412, and a third region 413. The third region 413 is provided with a recess 414 and a through-hole 415. The third region 413 is joined to the first negative electrode current collector 400 at the recess 414.

[0065] Next, the connection between the current collector and the tab portion 21 will be described. Fig. 11 is a cross-sectional view of the electrode body and the current collector of Fig. 10, viewed from the direction of the arrows XI-XI. Fig. 12 is a cross-sectional view showing a state in which the tab portion of the electrode body included in the battery according to embodiment 1 of the present technology is folded.

[0066] 11 , with the tip portion 221 of the positive electrode tab group 210 including the multiple positive electrode tabs 220 adjacent to the first region 311 of the second positive electrode current collector 310, the first region 311 and the positive electrode tab group 210 are joined. This joining forms a tab joint 320. The first region 311 and the positive electrode tab group 210 can be joined by ultrasonic welding, resistance welding, laser welding, or the like.

[0067] As shown in FIG. 12 , the positive electrode tab group 210 on which the tab joint 320 is formed is curved by being bent. The bent tip portion 221 of the tab portion 21 faces at least one of the pair of second side walls 104a, 104b. In the present embodiment, the tip portion 221 faces one of the second side walls 104a. In this manner, the second positive electrode current collector 310 faces the side surface of the battery case 10 due to the positive electrode tab group 210 being bent. Note that the tab joint 320 may be joined to the surface of the first region 311 opposite to the electrode body 20.

[0068] Similar to the positive electrode tab group 210, the negative electrode tab group 260 is adjacent to the first region 411 of the second negative electrode current collector 410, and the first region 411 and the negative electrode tab group 260 are joined together. This joining forms a tab joint. The negative electrode tab group 260 with the tab joint formed thereon is curved by being bent. The bent tip end of the tab portion 21 faces at least one of the pair of second side walls 104a, 104b. In the present embodiment, the tip end faces the other second side wall 104b. In this way, the second negative electrode current collector 410 faces the other second side wall 104b due to the negative electrode tab group 260 being bent.

[0069] In the first region 311 of the second positive electrode current collector 310, the tab joint portion 320 is preferably disposed closer to the base of the positive electrode tab group 210. With this configuration, when the positive electrode tab group 210 is bent, a curved shape can be stably formed near the base of the positive electrode tab group 210. In the first region 411 of the second negative electrode current collector 410, the position at which the negative electrode tab group 260 is joined is also the same as in the case of the second positive electrode current collector 310.

[0070] 2, the end of the second positive electrode current collector 310 on the bottom 102 side of the exterior body 100 is preferably located closer to the bottom 102 than the end of the positive electrode tab group 210 on the bottom 102 side of the exterior body 100. With this configuration, the positive electrode tab group 210 can be folded stably in the step of folding the positive electrode tab group 210. The same applies to the lower end of the second negative electrode current collector 410 as to the second positive electrode current collector 310.

[0071] Next, the sealing plate 110 will be described. Fig. 13 is an upper perspective view showing the configuration of a sealing plate and a portion of a current collector included in the battery according to embodiment 1 of the present technology. Fig. 14 is a lower perspective view showing the configuration of a sealing plate and a portion of a current collector included in the battery according to embodiment 1 of the present technology. Fig. 15 is an enlarged cross-sectional view of portion XV of the battery shown in Fig. 2. Fig. 16 is an enlarged cross-sectional view of portion XVI of the battery shown in Fig. 2. Fig. 13 shows the sealing plate 110 from the outside of the battery 1, and Fig. 14 shows the sealing plate 110 from the inside of the battery 1.

[0072] As shown in FIGS. 13 and 15, the sealing plate 110 has a positive electrode terminal mounting hole 114 near one end and a negative electrode terminal mounting hole 115 near the other end.

[0073] As shown in Figures 13 to 15, in the sealing plate 110, a first external insulating member 231 is arranged around the positive electrode terminal mounting hole 114 on the surface opposite the electrode body 20 side, and an internal insulating member 240 and a first positive electrode current collector 300 are arranged around the positive electrode terminal mounting hole 114 on the surface facing the electrode body 20.

[0074] The positive electrode terminal 230 is inserted from the outside of the battery 1 into the through-hole 232h of the second outer insulating member 232, the positive electrode terminal mounting hole 114 of the sealing plate 110, the through-hole 240h of the inner insulating member 240, and the through-hole 301h of the first positive electrode current collector 300. The positive electrode terminal 230 is crimped onto the first positive electrode current collector 300 to form a crimped portion 230A. Note that the crimped portion 230A of the positive electrode terminal 230 may be welded to the first positive electrode current collector 300 after being crimped.

[0075] As shown in Figures 13, 14 and 16, in the sealing plate 110, a first external insulating member 281 is arranged on the surface of the negative electrode terminal mounting hole 115 opposite the electrode body 20, and an internal insulating member 290 and a first negative electrode current collector 400 are arranged on the surface of the negative electrode terminal mounting hole 115 facing the electrode body 20.

[0076] The negative electrode terminal 280 is inserted from the outside of the battery 1 into the through-hole 282h of the second outer insulating member 282, the negative electrode terminal mounting hole 115 of the sealing plate 110, the through-hole 290h of the inner insulating member 290, and the through-hole 401h of the first negative electrode current collector 400. The negative electrode terminal 280 is crimped onto the first negative electrode current collector 400 to form a crimped portion 280A. Note that the crimped portion 280A of the negative electrode terminal 280 may be welded to the first negative electrode current collector 400 after being crimped.

[0077] There are no particular limitations on the timing at which the positive electrode external conductive member 60 is connected to the positive electrode terminal 230 or the negative electrode external conductive member 70 is connected to the negative electrode terminal 280. The timing of this connection may be after the positive electrode terminal 230 and the negative electrode terminal 280 are fixed to the sealing plate 110, or after the electrolyte injection hole 111 of the sealing plate 110 connected to the exterior body 100 is sealed.

[0078] 13 to 15, the first positive electrode current collector 300, which is an extended current collector, has an L-shape in cross section. The first positive electrode current collector 300 has a base 301 and a current collector connection part 302. The base 301 is disposed between the electrode body 20 and the sealing plate 110, with the inner insulating member 240 interposed between them, along the sealing plate 110.

[0079] The current collector connection part 302 is bent from the end of the base part 301 and extends toward the bottom part 102. The current collector connection part 302 is connected to the third region 313 of the second positive electrode current collector 310. The current collector connection part 302 is disposed between one second side wall 104a of the exterior body 100 and the electrode body 20.

[0080] 13, 14, and 16, the first negative electrode current collector 400, which is an extended current collector, has an L-shape in cross section. The first negative electrode current collector 400 has a base 401 and a current collector connection part 402. The base 401 is disposed between the electrode body 20 and the sealing plate 110, with the inner insulating member 290 interposed between them, along the sealing plate 110.

[0081] The current collector connection part 402 is bent from the end of the base part 401 and extends toward the bottom part 102. The current collector connection part 402 is connected to the third region 413 of the second negative electrode current collector 410. The current collector connection part 402 is disposed between the other second side wall 104b of the exterior body 100 and the electrode body 20.

[0082] Next, the connection between the first current collector and the second current collector will be described. As shown in Fig. 3, three electrode assemblies 20, each having a second positive electrode current collector 310 and a second negative electrode current collector 410 attached thereto, are arranged side by side. At this time, for each of the three electrode assemblies 20, the positive electrode tab groups 210 are arranged on the same side, and the negative electrode tab groups 260 are also arranged on the same side.

[0083] With each of the positive electrode tab groups 210 of the three electrode bodies 20 curved, the second positive electrode current collector 310 attached to the three electrode bodies 20 is joined to the current collector connection portion 302 of the first positive electrode current collector 300 fixed to the sealing plate 110. As a result, a joint between the current collector connection portion 302 and the third region 313 is formed in the recess 314.

[0084] With each of the negative electrode tab groups 260 of the three electrode bodies 20 curved, the second negative electrode current collector 410 attached to the three electrode bodies 20 is joined to the current collector connection portion 402 of the first negative electrode current collector 400 fixed to the sealing plate 110. As a result, a joint between the current collector connection portion 402 and the third region 413 is formed in the recess 414.

[0085] The first positive electrode current collector 300 and the second positive electrode current collector 310, or the first negative electrode current collector 400 and the second negative electrode current collector 410, can be connected by ultrasonic welding, resistance welding, laser welding using high-energy rays, or the like. Laser welding is particularly preferred.

[0086] Next, the insertion of the electrode assembly 20 into the exterior housing 100 will be described. As shown in Fig. 2, the electrode assembly 20 is placed inside a bag- or box-shaped insulating sheet 50. The electrode assembly 20 covered with the insulating sheet 50 is inserted into the exterior housing 100. This causes multiple wound electrode assemblies to be housed inside the battery case 10. Next, a sealing plate 110 is joined to the opening 101 of the exterior housing 100 by laser welding or the like.

[0087] Thereafter, a nonaqueous electrolyte is poured through an electrolyte pouring hole 111 provided in the sealing plate 110, and the electrolyte pouring hole 111 is sealed with a sealing member 112. This completes the battery 1. Known materials can be used for the positive electrode plate 200, the negative electrode plate 250, the separator, the electrolyte, and the various mechanical components used in the battery 1 according to this embodiment.

[0088] The structure of the insulating sheet 50 according to the first embodiment of the present technology will be described in detail below.

[0089] Fig. 17 is a perspective view showing the positional relationship between a battery case and an insulating sheet included in the battery according to the first embodiment of the present technology. Fig. 18 is a perspective view showing the configuration of the battery according to the first embodiment of the present technology, excluding the exterior body included in the battery.

[0090] As shown in Figures 17 and 18, the insulating sheet 50 includes a bottom surface portion 500, a first side surface portion 510, a second side surface portion 511, a first left side piece portion 520, a second left side piece portion 521, a left bottom piece portion 522, a first left side connection portion 523, and a second left side connection portion 524.

[0091] The bottom surface portion 500 is disposed between the electrode body 20 and the bottom portion 102 of the exterior body 100. The bottom surface portion 500 faces the bottom portion 102.

[0092] The first side surface portion 510 is disposed between one of the pair of first side walls 103a, 103b and the electrode body 20. In the present embodiment, the first side surface portion 510 is disposed between one of the first side walls 103a and the electrode body 20.

[0093] The second side surface portion 511 is disposed between the other of the pair of first side walls 103a, 103b and the electrode body 20. In the present embodiment, the second side surface portion 511 is disposed between the other first side wall 103b and the electrode body 20.

[0094] The first left piece 520 is bent from one lateral end of the first side surface portion 510. In this embodiment, the first left piece 520 is bent from the lateral end of the first side surface portion 510 on the positive electrode side of the battery 1.

[0095] The first left piece 520 is disposed between one of the pair of second side walls 104a, 104b and the electrode body 20. In the present embodiment, the first left piece 520 is disposed between one of the second side walls 104a and the electrode body 20.

[0096] The second left piece 521 is bent from one lateral end of the second side surface portion 511. In this embodiment, the second left piece 521 is bent from the lateral end of the second side surface portion 511 on the positive electrode side of the battery 1.

[0097] The second left-side piece 521 is arranged between one of the pair of second side walls 104a, 104b and the electrode body 20, at least partially overlapping with the first left-side piece 520. In the present embodiment, the second left-side piece 521 is arranged between one of the second side walls 104a and the electrode body 20.

[0098] The left bottom piece 522 rises from one lateral end of the bottom surface 500. In this embodiment, the left bottom piece 522 rises from the lateral end of the bottom surface 500 on the positive electrode side of the battery 1.

[0099] The left bottom piece 522 is located outside the overlapping first left piece 520 and second left piece 521 between one of the pair of second side walls 104a, 104b and the electrode body 20. The left bottom piece 522 in this embodiment is located between one second side wall 104a and the electrode body 20, closer to one second side wall 104a than the first left piece 520 and second left piece 521.

[0100] The first left-side connecting portion 523 is provided contiguous with each of the first left-side piece 520 and the left-side bottom piece 522. The first left-side connecting portion 523 is bent at the boundary between each of the first left-side piece 520 and the left-side bottom piece 522, and is sandwiched between the first left-side piece 520 and the left-side bottom piece 522.

[0101] The second left-side connecting portion 524 is provided contiguous with each of the second left-side piece 521 and the left-side bottom piece 522. The second left-side connecting portion 524 is bent at the boundary between each of the second left-side piece 521 and the left-side bottom piece 522, and is sandwiched between the second left-side piece 521 and the left-side bottom piece 522.

[0102] FIG. 19 is an enlarged perspective view of the portion XIX of the battery shown in FIG.

[0103] 19 , a first communication passage 530 that connects the inside and outside of the insulating sheet 50 is formed in the insulating sheet 50. The first communication passage 530 is defined by a first left piece 520, a second left piece 521, a left bottom piece 522, a first left connection portion 523, and a second left connection portion 524. The first communication passage 530 is a gap formed by folding the first left piece 520, the second left piece 521, the left bottom piece 522, the first left connection portion 523, and the second left connection portion 524 adjacent to each other, and the first communication passage 530 allows the electrolyte to flow between the inside and outside of the insulating sheet 50.

[0104] The first communication passage 530 has a first open end 531. The first open end 531 is located at the end of each of the first left connection portion 523 and the second left connection portion 524 on the opening 101 side of the exterior body 100. In the present embodiment, the first open end 531 is located at the end of each of the left bottom piece 522, the first left connection portion 523, and the second left connection portion 524 on the opening 101 side of the exterior body 100.

[0105] FIG. 20 is a development view showing the configuration of an insulating sheet included in the battery according to the first embodiment of the present technology.

[0106] 18 and 20, a single insulating sheet 50 is folded to form a cylindrical shape with a bottom. As shown in Fig. 20, the bottom surface portion 500 has a rectangular shape having a pair of long sides and a pair of short sides perpendicular to the pair of long sides.

[0107] The first side surface portion 510 is connected to one of the pair of long sides of the bottom surface portion 500. Specifically, the first side surface portion 510 and the bottom surface portion 500 are continuously connected over the entire length of one of the pair of long sides of the bottom surface portion 500.

[0108] The second side surface portion 511 is connected to the other of the pair of long sides of the bottom surface portion 500. Specifically, the second side surface portion 511 and the bottom surface portion 500 are continuously connected over the entire length of the other of the pair of long sides of the bottom surface portion 500.

[0109] The bottom surface portion 500 and the left bottom piece portion 522 are continuously connected over the entire length of one of the pair of short sides of the bottom surface portion 500.

[0110] The first side surface portion 510 and the first left side piece 520 are continuously connected over the entire length of the range facing the electrode body 20 at the boundary between the first side surface portion 510 and the first left side piece 520. In the present embodiment, the first side surface portion 510 and the first left side piece 520 are continuously connected over the entire length of their boundary. However, a notch or a through-hole may be formed in the upper end portion of the boundary between the first side surface portion 510 and the first left side piece 520 that does not face the electrode body 20, so that there may be a location where the first side surface portion 510 and the first left side piece 520 are discontinuous.

[0111] At the boundary between the second side surface portion 511 and the second left side piece 521, the second side surface portion 511 and the second left side piece 521 are continuously connected over the entire length of the range facing the electrode body 20. In the present embodiment, the second side surface portion 511 and the second left side piece 521 are continuously connected over the entire length of their boundary. However, at the upper end of the boundary between the second side surface portion 511 and the second left side piece 521 that does not face the electrode body 20, a notch or a through hole may be formed, so that there may be a location where the second side surface portion 511 and the second left side piece 521 are discontinuous.

[0112] The insulating sheet 50 has a first bending line 551, a second bending line 552, a third bending line 553, a fourth bending line 554, a fifth bending line 555, a sixth bending line 556, a seventh bending line 557, an eighth bending line 558, and a ninth bending line 559 formed thereon.

[0113] The first folding line 551 is formed at the boundary between the bottom surface portion 500 and the first side surface portion 510. The second folding line 552 is formed at the boundary between the bottom surface portion 500 and the second side surface portion 511. The third folding line 553 is formed at the boundary between the first side surface portion 510 and the first left piece 520. The fourth folding line 554 is formed at the boundary between one of the pair of short sides of the bottom surface portion 500 and the left bottom piece 522. The fifth folding line 555 is formed at the boundary between the second side surface portion 511 and the second left piece 521. The sixth folding line 556 is formed at the boundary between the first left piece 520 and the first left connecting portion 523. The seventh folding line 557 is formed at the boundary between the left bottom piece 522 and the first left connecting portion 523. The eighth folding line 558 is formed at the boundary between the left bottom piece 522 and the second left connecting portion 524. The ninth folding line 559 is formed at the boundary between the second left piece 521 and the second left connecting portion 524.

[0114] Each of first bending line 551, second bending line 552, third bending line 553, fourth bending line 554, fifth bending line 555, seventh bending line 557, and eighth bending line 558 is formed by being recessed from one surface side of insulating sheet 50. Each of sixth bending line 556 and ninth bending line 559 is formed by being recessed from the other surface side of insulating sheet 50. This allows left bottom piece 522 to be positioned outward of first left piece 520 and second left piece 521.

[0115] The insulating sheet 50 further includes a first intersection 540 and a second intersection 541. The first intersection 540 is an intersection of a first folding line 551, a third folding line 553, a fourth folding line 554, a sixth folding line 556, and a seventh folding line 557. The second intersection 541 is an intersection of a second folding line 552, a fourth folding line 554, a fifth folding line 555, an eighth folding line 558, and a ninth folding line 559. The first intersection 540 and the second intersection 541 are located at corners on one side of a pair of short sides of the bottom surface portion 500.

[0116] FIG. 21 is a perspective view showing a state in which an insulating sheet included in the battery according to the first embodiment of the present technology is folded.

[0117] As shown in FIG. 21, the insulating sheet 50 is formed into a bottomed cylindrical shape by folding the first side surface portion 510, the second side surface portion 511, the first left side piece portion 520, the second left side piece portion 521, the left bottom piece portion 522, the first left side connection portion 523 and the second left side connection portion 524 relative to the bottom surface portion 500 at the first to ninth folding lines 551 to 559.

[0118] Specifically, the first left-side piece 520 is folded so as to be on the outer side of the second left-side piece 521. The first left-side piece 520 and the first left-side connecting portion 523 are folded so as to be sandwiched between the left-side bottom piece 522 and the second left-side connecting portion 524. As a result, as shown in FIG. 19 , the first left-side piece 520, the second left-side piece 521, the left bottom piece 522, the first left-side connecting portion 523, and the second left-side connecting portion 524, which are folded over each other, form a first communication passage 530 in the insulating sheet 50, which is a gap that communicates between the inside and outside of the insulating sheet 50.

[0119] Fig. 22 is a side view of the battery of Fig. 18 as seen from the direction of arrow XXII. As shown in Fig. 22, insulating sheet 50 further has a first overlapping region 571, a second overlapping region 572, a third overlapping region 573, and a fourth overlapping region 574.

[0120] The first overlapping region 571 is a region where the first left piece 520 and the second left piece 521 overlap each other between one of the pair of second side walls 104a, 104b and the electrode body 20. The first overlapping region 571 in the present embodiment is located between one of the second side walls 104a and the electrode body 20.

[0121] The second overlapping region 572 is a region where the first left side piece 520, the second left side piece 521, and the left bottom piece 522 overlap with each other. In the present embodiment, the second overlapping region 572 overlaps not only the first left side piece 520, the second left side piece 521, and the left bottom piece 522, but also the first left connecting portion 523 and the second left connecting portion 524.

[0122] The third overlapping region 573 is an overlapping region between the first left piece 520, the left bottom piece 522, and the first left connecting portion 523. The fourth overlapping region 574 is an overlapping region between the second left piece 521, the left bottom piece 522, and the second left connecting portion 524.

[0123] First opening edge 531 is located at the end position of third overlapping region 573 and fourth overlapping region 574 on the opening 101 side of exterior body 100. First opening edge 531 in the present embodiment is located at the end of second overlapping region 572, third overlapping region 573, and fourth overlapping region 574 on the opening 101 side.

[0124] In a direction perpendicular to the bottom surface portion 500, the shortest distance L between the bottom surface portion 500 and the first opening end 531 is 5 mm or more. With this configuration, it is possible to ensure a creepage distance of 5 mm or more between an end portion on a short side of the bottom surface of the electrode body 20 (end portion 20e, described later) and the exterior body 100. In the insulating sheet 50 according to the present embodiment, there is no location where the inside and outside of the insulating sheet 50 communicate within a radius of 5 mm from each of the first intersection 540 and the second intersection 541, so it is possible to ensure a creepage distance of 5 mm or more between the end portion on a short side of the bottom surface of the electrode body 20 (end portion 20e, described later) and the exterior body 100.

[0125] Figure 23 is a cross-sectional view of the battery of Figure 17 as seen from the direction of the arrows along line XXIII-XXIII. Figure 23 shows a cross section perpendicular to the bottom surface portion 500 at the position where the sixth folding line 556 and the ninth folding line 559 intersect.

[0126] As shown in Figure 23, the insulating sheet 50 is arranged around the corner on the bottom 102 side, from the electrode body 20 toward the outer casing 100, in the order of second left side piece 521, second left side connection portion 524, first left side piece 520, first left side connection portion 523 and left side bottom piece 522.

[0127] The first communication passage 530 is located on the shortest path for the electrolyte to penetrate from the outside of the insulating sheet 50 to the end portion of the electrode assembly 20 that is closest to the ridge portion 104e on the bottom 102 side of the exterior body 100 and one of the pair of second side walls 104a, 104b. In the present embodiment, the first communication passage 530 is located on the shortest path for the electrolyte 80 to penetrate from the outside of the insulating sheet 50 to the end portion 20e of the electrode assembly 20 that is closest to the ridge portion 104e on the bottom 102 side of the exterior body 100 and one of the second side walls 104a.

[0128] A short-circuit path through which a high voltage is applied between batteries 1 located at both ends of multiple batteries 1 connected in series may be formed due to water ingress around the battery 1, etc. In this case, the highest voltage is applied inside the battery 1 located on the short-circuit path between the end 20e of the electrode body 20 and the ridge portion 104e of the exterior body 100. In the battery 1 according to the present embodiment, the first communication path 530 is located on the shortest infiltration path of the electrolyte 80 that infiltrates into the end 20e of the electrode body 20 from the outside of the insulating sheet 50. This ensures a creepage distance between the end 20e of the electrode body 20 and the ridge portion 104e of the exterior body 100, even when a high voltage is applied between the end 20e of the electrode body 20 and the ridge portion 104e of the exterior body 100. This makes it possible to suppress the occurrence of partial discharge between the end 20e of the electrode body 20 and the ridge portion 104e of the exterior body 100.

[0129] Fig. 24 is a side view of the battery of Fig. 18 as viewed from the direction of arrow XXIV. As shown in Fig. 17, 20, and 24, insulating sheet 50 includes a first right piece 525, a second right piece 526, a right bottom piece 527, a first right connection portion 528, and a second right connection portion 529.

[0130] The first right piece 525 is bent from the other lateral end of the first side surface portion 510. In this embodiment, the first right piece 525 is bent from the lateral end of the first side surface portion 510 on the negative electrode side of the battery 1.

[0131] The first right piece 525 is disposed between the other of the pair of second side walls 104a, 104b and the electrode body 20. In the present embodiment, the first right piece 525 is disposed between the other second side wall 104b and the electrode body 20.

[0132] The second right piece 526 is bent from the other lateral end of the second side surface portion 511. In this embodiment, the second right piece 526 is bent from the lateral end of the second side surface portion 511 on the negative electrode side of the battery 1.

[0133] The second right piece 526 is disposed between the other of the pair of second side walls 104a, 104b and the electrode body 20, at least partially overlapping with the first right piece 525. In the present embodiment, the second right piece 526 is disposed between the other second side wall 104b and the electrode body 20.

[0134] The right bottom piece 527 rises from the other lateral end of the bottom surface 500. In this embodiment, the right bottom piece 527 rises from the lateral end of the bottom surface 500 on the negative electrode side of the battery 1.

[0135] The right bottom piece 527 is located outside the overlapping first right piece 525 and second right piece 526, between the other of the pair of second side walls 104a, 104b and the electrode body 20. In the present embodiment, the right bottom piece 527 is located between the other second side wall 104b and the electrode body 20, closer to the other second side wall 104b than the first right piece 525 and second right piece 526.

[0136] The first right-side connecting portion 528 is provided contiguous with each of the first right-side piece 525 and the right-side bottom piece 527. The first right-side connecting portion 528 is bent at the boundary between each of the first right-side piece 525 and the right-side bottom piece 527, and is sandwiched between the first right-side piece 525 and the right-side bottom piece 527.

[0137] The second right-side connecting portion 529 is provided contiguous with each of the second right-side piece 526 and the right-side bottom piece 527. The second right-side connecting portion 529 is bent at the boundary between each of the second right-side piece 526 and the right-side bottom piece 527, and is sandwiched between the second right-side piece 526 and the right-side bottom piece 527.

[0138] The insulating sheet 50 has a tenth bending line 560, an eleventh bending line 561, a twelfth bending line 562, a thirteenth bending line 563, a fourteenth bending line 564, a fifteenth bending line 565, and a sixteenth bending line 566 formed thereon.

[0139] The tenth fold line 560 is formed at the boundary between the first side surface portion 510 and the first right piece 525. The eleventh fold line 561 is formed at the boundary between the other of the pair of short sides of the bottom surface portion 500 and the right bottom piece 527. The twelfth fold line 562 is formed at the boundary between the second side surface portion 511 and the second right piece 526. The thirteenth fold line 563 is formed at the boundary between the first right piece 525 and the first right connecting portion 528. The fourteenth fold line 564 is formed at the boundary between the right bottom piece 527 and the first right connecting portion 528. The fifteenth fold line is formed at the boundary between the right bottom piece 527 and the second right connecting portion 529. The sixteenth fold line 566 is formed at the boundary between the second right piece 526 and the second right connecting portion 529.

[0140] A second communication passage 532 that connects the inside and outside of the insulating sheet 50 is formed in the insulating sheet 50. The second communication passage 532 is defined by the first right piece 525, the second right piece 526, the right bottom piece 527, the first right connection portion 528, and the second right connection portion 529. The first communication passage 530 is a gap formed by folding the first right piece 525, the second right piece 526, the right bottom piece 527, the first right connection portion 528, and the second right connection portion 529 adjacent to each other, and the electrolyte can flow between the inside and outside of the insulating sheet 50 through the second communication passage 532.

[0141] The second communication passage 532 has a second open end 533. The second open end 533 is located at the end of each of the first right connection portion 528 and the second right connection portion 529 on the opening 101 side of the exterior body 100. In the present embodiment, the second open end 533 is located at the end of each of the right bottom piece 527, the first right connection portion 528, and the second right connection portion 529 on the opening 101 side of the exterior body 100.

[0142] The insulating sheet 50 further includes a fifth overlapping region 575, a sixth overlapping region 576, a seventh overlapping region 577, and an eighth overlapping region 578.

[0143] The fifth overlapping region 575 is a region where the first right piece 525 and the second right piece 526 overlap each other between the other of the pair of second side walls 104a, 104b and the electrode body 20. The fifth overlapping region 575 in the present embodiment is located between the other second side wall 104b and the electrode body 20.

[0144] The sixth overlapping region 576 is a region where the first right piece 525, the second right piece 526, and the right bottom piece 527 overlap one another. In the present embodiment, the sixth overlapping region 576 overlaps not only the first right piece 525, the second right piece 526, and the right bottom piece 527, but also the first right connecting portion 528 and the second right connecting portion 529.

[0145] The seventh overlapping region 577 is an overlapping region between the first right piece 525, the right bottom piece 527, and the first right connecting portion 528. The eighth overlapping region 578 is an overlapping region between the second right piece 526, the right bottom piece 527, and the second right connecting portion 529.

[0146] Second opening edge 533 is located at the end position of each of seventh overlapping region 577 and eighth overlapping region 578 on the opening 101 side of exterior body 100. Second opening edge 533 in the present embodiment is located at the end of each of sixth overlapping region 576, seventh overlapping region 577, and eighth overlapping region 578 on the opening 101 side.

[0147] The insulating sheet 50 further includes a third intersection 542 and a fourth intersection 543. The third intersection 542 is an intersection of the first folding line 551, the tenth folding line 560, the eleventh folding line 561, the thirteenth folding line 563, and the fourteenth folding line 564. The fourth intersection 543 is an intersection of the second folding line 552, the eleventh folding line 561, the twelfth folding line 562, the fifteenth folding line 565, and the sixteenth folding line 566. The third intersection 542 and the fourth intersection 543 are located at the corners of the other of the pair of short sides of the bottom surface portion 500.

[0148] The second communication passage 532 is located on the shortest path for the electrolyte 80 to penetrate from the outside of the insulating sheet 50 to the end of the electrode assembly 20 that is closest to the ridge line on the bottom 102 side of the exterior body 100 and the other of the pair of second side walls 104a, 104b. In the present embodiment, the second communication passage 532 is located on the shortest path for the electrolyte to penetrate from the outside of the insulating sheet 50 to the end of the electrode assembly 20 that is closest to the ridge line on the bottom 102 side of the exterior body 100 and the other of the pair of second side walls 104b.

[0149] Except for the configuration described above, the first right side piece 525, the second right side piece 526, the right bottom piece 527, the first right side connection portion 528 and the second right side connection portion 529, and the tenth to sixteenth folding lines 560 to 566 of the insulating sheet 50 have the same configuration as the first left side piece 520, the second left side piece 521, the left bottom piece 522, the first left side connection portion 523 and the second left side connection portion 524, and the third to ninth folding lines 553 to 559.

[0150] In the battery 1 of this embodiment, the first communication passage 530 provided in the insulating sheet 50 is located on the shortest penetration path of the electrolyte 80 penetrating from outside the insulating sheet 50 to the end of the electrode body 20 that is closest to the bottom 102 side of the outer casing 100 and the ridge portion of one of the pair of second side walls 104a, 104b.Therefore, even when a high voltage is applied between the end of the electrode body 20 and the ridge portion of the outer casing 100, a creeping distance between the end of the electrode body 20 and the ridge portion of the outer casing 100 can be secured, thereby suppressing the occurrence of partial discharge between the end of the electrode body 20 and the ridge portion of the outer casing 100.

[0151] In the battery 1 according to the present embodiment, the shortest distance between the bottom surface 500 and the first opening end 531 in the direction perpendicular to the bottom surface 500 is 5 mm or more, thereby suppressing the occurrence of partial discharge between the end 20e of the electrode body 20 and the ridge 104e of the exterior body 100. Note that the shortest distance is not limited to 5 mm and is set appropriately based on the creepage distance required depending on the voltage of the battery 1, etc.

[0152] In battery 1 according to the present embodiment, by making the shortest distance between first region 311 and one of second side walls 104a in the direction perpendicular to one of second side walls 104a shorter than the shortest distance between third region 313 and one of second side walls 104a, it is possible to ensure a long insulation distance between electrode body 20 and exterior body 100 at a position close to the open end of box-shaped insulating sheet 50. The first region 411, third region 413, and the other of second side walls 104b also have the same configuration as first region 311, third region 313, and one of second side walls 104a, thereby achieving the same effect.

[0153] In the battery 1 according to this embodiment, an electrical connection path with the electrode body 20 of the battery case 10 can be easily configured by connecting the tab portion 21 to the positive electrode terminal 230 or the negative electrode terminal 280 using two components, the first positive electrode current collector 300 and the second positive electrode current collector 310, or the first negative electrode current collector 400 and the second negative electrode current collector 410.

[0154] In the battery 1 according to this embodiment, multiple wound electrode bodies are housed inside the insulating sheet 50 arranged in the battery case 10. This allows the radius of curvature of the end of the electrode body 20 on the bottom surface 500 side to be smaller, thereby ensuring a larger area through which the electrolyte 80 can penetrate into the electrode body 20, compared to when a single thick wound electrode body is housed, thereby preventing a shortage of the electrolyte 80 in the electrode body 20.

[0155] In the battery 1 of this embodiment, the first side surface portion 510 and the bottom surface portion 500 are continuously connected along the entire length of one of the pair of long sides of the bottom surface portion 500 of the insulating sheet 50, and the second side surface portion 511 and the bottom surface portion 500 are continuously connected along the entire length of the other of the pair of long sides of the bottom surface portion 500, thereby continuously insulating the electrode body 20 and the outer casing 100 at each of the first bending line 551 and the second bending line 552, thereby suppressing the occurrence of partial discharge.

[0156] In the battery 1 of this embodiment, the bottom surface portion 500 and the left bottom piece portion 522 are continuously connected along the entire length of one of the pair of short sides of the bottom surface portion 500 of the insulating sheet 50, thereby continuously insulating the electrode body 20 and the outer casing 100 at the fourth folding line 554 and suppressing the occurrence of partial discharge.

[0157] In the battery 1 of this embodiment, the first side surface portion 510 and the first left side piece 520 of the insulating sheet 50 are continuously connected along the entire length of the range facing the electrode body 20 at the boundary between the first side surface portion 510 and the first left side piece 520, and the second side surface portion 511 and the second left side piece 521 are continuously connected along the entire length of the range facing the electrode body 20 at the boundary between the second side surface portion 511 and the second left side piece 521, thereby continuously insulating the electrode body 20 and the outer casing 100 at each of the third bending line 553 and the fifth bending line 555, thereby suppressing the occurrence of partial discharge.

[0158] In the battery 1 according to this embodiment, each of the first bending line 551, the second bending line 552, the third bending line 553, the fourth bending line 554, the fifth bending line 555, the seventh bending line 557, and the eighth bending line 558 is formed by being recessed from one side of the insulating sheet 50, and each of the sixth bending line 556 and the ninth bending line 559 is formed by being recessed from the other side of the insulating sheet 50. As a result, the recessed side can be made the valley side of the fold, and therefore the insulating sheet 50 can be easily folded into a box shape.

[0159] In the battery 1 of this embodiment, the second communication passage 532 provided in the folded insulating sheet 50 is located on the shortest penetration path of the electrolyte 80 penetrating from outside the insulating sheet 50 to the end of the electrode body 20 that is closest to the bottom 102 side of the outer casing 100 and the ridge portion on the other side of the pair of second side walls 104a, 104b, thereby ensuring a creeping distance between the end of the electrode body 20 and the ridge portion of the outer casing 100, and thereby suppressing the occurrence of partial discharge between the end of the electrode body 20 and the ridge portion of the outer casing 100.

[0160] (Embodiment 2) The following describes a battery according to embodiment 2 of the present technology. The battery according to embodiment 2 of the present technology has a different insulating sheet configuration from battery 1 according to embodiment 1 of the present technology, and therefore, the description of the configuration that is the same as battery 1 according to embodiment 1 of the present technology will not be repeated.

[0161] Fig. 25 is a development view showing the configuration of an insulating sheet included in a battery according to embodiment 2 of the present technology. As shown in Fig. 25, insulating sheet 50A included in the battery according to the present embodiment includes bottom surface portion 500, first side surface portion 510, second side surface portion 511, first left-hand side piece 520, second left-hand side piece 521, left-hand bottom piece 522, first left-hand connection portion 523A, and second left-hand connection portion 524A.

[0162] The first left-side connecting portion 523A is provided contiguous with both the first left-side piece 520 and the left-side bottom piece 522. The second left-side connecting portion 524A is provided contiguous with both the second left-side piece 521 and the left-side bottom piece 522.

[0163] Insulating sheet 50A has a first bending line 551, a second bending line 552, a third bending line 553, a fourth bending line 554, a fifth bending line 555, a sixth bending line 556A, a seventh bending line 557A, an eighth bending line 558A, and a ninth bending line 559A formed thereon.

[0164] The sixth folding line 556A is formed at the boundary between the first left piece 520 and the first left connecting portion 523A. The sixth folding line 556A includes the short side portion of the first left piece 520 on the first left connecting portion 523A side.

[0165] The seventh folding line 557A is formed at the boundary between the left bottom piece 522 and the first left connecting portion 523A. The seventh folding line 557A includes the short side portion of the left bottom piece 522 on the first left connecting portion 523A side.

[0166] The eighth folding line 558A is formed at the boundary between the left bottom piece 522 and the second left connecting portion 524A. The eighth folding line 558A includes the short side portion of the left bottom piece 522 on the second left connecting portion 524A side.

[0167] The ninth folding line 559A is formed at the boundary between the second left piece 521 and the second left connecting portion 524A. The ninth folding line 559A includes the short side portion of the second left piece 521 on the second left connecting portion 524A side.

[0168] Insulating sheet 50A, first through-cutout portion 523h is formed in a region sandwiched between sixth bending line 556A and seventh bending line 557A and adjacent to first left-side connecting portion 523A. Second through-cutout portion 524h is formed in a region sandwiched between eighth bending line 558 and ninth bending line 559 and adjacent to second left-side connecting portion 524A. Note that first through-cutout portion 523h and second through-cutout portion 524h are not limited to cutout shapes, and may be a structure that allows communication between the inside and outside of insulating sheet 50, such as a slit, a through-hole, or a perforation.

[0169] First bending line 551, second bending line 552, third bending line 553, fourth bending line 554, fifth bending line 555, seventh bending line 557A, and eighth bending line 558A are each formed by being recessed from one surface side of insulating sheet 50. Sixth bending line 556A and ninth bending line 559A are each formed by being recessed from the other surface side of insulating sheet 50. This allows left bottom piece 522 to be positioned outside first left piece 520 and second left piece 521.

[0170] Fig. 26 is a side view showing the internal configuration of the battery according to embodiment 2 of the present technology. As shown in Fig. 26, first left-side connection portion 523A is bent at the boundary between first left-side piece 520 and left-side bottom piece 522, and is sandwiched between first left-side piece 520 and left-side bottom piece 522. Second left-side connection portion 524A is bent at the boundary between second left-side piece 521 and left-side bottom piece 522, and is sandwiched between second left-side piece 521 and left-side bottom piece 522.

[0171] A first communication passage 530A is formed in the insulating sheet 50A, connecting the inside and outside of the insulating sheet 50A. The first communication passage 530A is defined by the first left piece 520, the second left piece 521, the left bottom piece 522, the first left connection portion 523A, and the second left connection portion 524A. The first communication passage 530A is a gap formed by folding the first left piece 520, the second left piece 521, the left bottom piece 522, the first left connection portion 523A, and the second left connection portion 524A adjacent to each other, and the electrolyte can flow between the inside and outside of the insulating sheet 50A through the first communication passage 530A.

[0172] First communication passage 530A has first open end 531A. First open end 531A is located at the end of first left connection portion 523A and second left connection portion 524A on the opening 101 side of exterior body 100, in first communication passage 530A.

[0173] The insulating sheet 50A further includes a first overlapping region 571, a second overlapping region 572A, a third overlapping region 573A, a fourth overlapping region 574A, a ninth overlapping region 579, and a tenth overlapping region 580.

[0174] The first overlapping region 571 is a region where the first left-side piece part 520 and the second left-side piece part 521 overlap each other. The second overlapping region 572A is a region where the first left-side piece part 520, the second left-side piece part 521, and the left-side bottom piece part 522 overlap each other. The third overlapping region 573 is a region where the first left-side piece part 520, the left-side bottom piece part 522, and the first left-side connecting part 523A overlap. The fourth overlapping region 574 is a region where the second left-side piece part 521, the left-side bottom piece part 522, and the second left-side connecting part 524A overlap.

[0175] The ninth overlapping region 579 is a region where the first left-side piece part 520 and the left-side bottom piece part 522 overlap each other. The tenth overlapping region 580 is a region where the second left-side piece part 521 and the left-side bottom piece part 522 overlap each other.

[0176] The first opening end 531A is located at the position of the end on the opening 101 side of the exterior body 100 of each of the third overlapping region 573A and the fourth overlapping region 574A. As shown in FIG. 26, the first opening end 531A in the present embodiment is located on the bottom surface part 500 side from the position where the sixth bending line 556A and the ninth bending line 559A intersect.

[0177] When the width dimension in the direction in which the pair of first side walls 103a and 103b of the electrode body 20 face each other is W, and the height dimension from the bottom surface part 500 to the first opening end 531A in the direction orthogonal to the bottom surface part 500 is H, the width dimension W and the height dimension H satisfy the relationship of H < W / 2. Due to this relationship, the first opening end 531A is close to the end on the bottom surface part 500 side of the electrode body 20.

[0178] Note that the first right-side piece part 525, the second right-side piece part 526, the right-side bottom piece part 527, the first right-side connecting part 528A, and the second right-side connecting part 529A, as well as the tenth to twelfth bending lines 560 to 562 and the thirteenth to sixteenth bending lines 563A to 566A in the insulating sheet 50A of the present embodiment, have the same configuration as the first left-side piece part 520, the second left-side piece part 521, the left-side bottom piece part 522, the first left-side connecting part 523A, and the second left-side connecting part 524A, as well as the third to fifth bending lines 553 to 555 and the sixth to ninth bending lines 556A to 559A.

[0179] In the battery according to the present embodiment, since the first through-removed portion 523h and the second through-removed portion 524h are formed in the insulating sheet 50A, in the direction orthogonal to the bottom surface portion 500, compared with the case where the first through-removed portion 523h and the second through-removed portion 524h are not formed, the first opening end 531A of the first communication path 530A is located at a position closer to the bottom surface portion 500. Therefore, while suppressing the occurrence of partial discharge between the end portion 20e of the electrode body 20 and the ridge line portion 104e of the exterior body 100, it is possible to make the electrolytic solution easily penetrate from the outside to the inside of the insulating sheet 50.

[0180] In the battery 1 according to the present embodiment, the width dimension W in the direction in which the pair of first side walls 103a and 103b of the electrode body 20 face each other and the height dimension H from the bottom surface portion 500 to the first opening end 531A in the direction orthogonal to the bottom surface portion 500 satisfy the relationship H < W / 2. As a result, the first opening end 531A can be brought close to the end portion on the bottom surface portion 500 side of the electrode body 20. Therefore, even when the amount of the electrolytic solution outside the insulating sheet 50 is small, the electrolytic solution can penetrate into the inside of the insulating sheet 50. In the present embodiment as well, in the direction orthogonal to the bottom surface portion 500, it is preferable that the shortest distance between the bottom surface portion 500 and the first opening end 531A is 5 mm or more.

[0181] As described above, the embodiments of the present technology have been described. However, it should be considered that the disclosed embodiments are illustrative in all respects and not restrictive. The scope of the present technology is indicated by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

Explanation of Reference Numerals

[0182] REFERENCE SIGNS LIST 1 battery, 10 battery case, 20 electrode body, 20e end, 21 tab portion, 30 positive electrode current collector, 40 negative electrode current collector, 50, 50A insulating sheet, 60 positive electrode external conductive member, 70 negative electrode external conductive member, 80 electrolyte, 100 outer casing, 101 opening, 102 bottom, 103a, 103b first side wall, 104a, 104b second side wall, 104e ridge portion, 110 sealing plate, 111 electrolyte injection hole, 112 sealing member, 113 gas release valve, 114 positive electrode terminal mounting hole, 115 negative electrode terminal mounting hole, 200 positive electrode plate, 200S positive electrode base plate, 201 positive electrode core, 202 positive electrode active material layer, 203 positive electrode protective layer, 210 Positive electrode tab group, 220 Positive electrode tab, 221 Tip portion, 230 Positive electrode terminal, 230A, 280A Crimping portion, 231, 281 First outer insulating member, 232, 282 Second outer insulating member, 232h, 240h, 282h, 290h, 301h, 315, 401h, 415 Through hole, 240, 290 Internal insulating member, 250 Negative electrode plate, 250S Negative electrode base plate, 251 Negative electrode core, 252 Negative electrode active material layer, 260 Negative electrode tab group, 270 Negative electrode tab, 280 Negative electrode terminal, 300 First positive electrode current collector, 301, 401 Base portion, 302, 402 Current collector connection portion, 310 Second positive electrode current collector, 311, 411 1st region, 312,412 2nd region, 313,413 3rd region, 314,414 recess, 316 fuse hole, 320 tab joint, 400 1st negative electrode current collector, 410 2nd negative electrode current collector, 500 bottom part, 510 1st side part, 511 2nd side part, 520 1st left side part, 521 2nd left side piece, 522 Left side bottom piece, 523,523A 1st left side connection, 523h 1st through cutout, 524,524A 2nd left side connection, 524h 2nd through cutout, 525 1st right side piece, 526 2nd right side piece, 527 Right side bottom piece, 528 1st right side connection, 529 2nd right side connection, 530,530A 1st communication passage, 531,531A First opening end, 532, second communication passage, 533, second opening end, 540, first intersection, 541, second intersection, 542, third intersection, 543, fourth intersection, 551, first bending line, 552, second bending line, 553, third bending line, 554, fourth bending line, 555, fifth bending line, 556, 556A, sixth bending line, 557, 557A, seventh bending line, 558,558A 8th fold line, 559, 559A 9th fold line, 560 10th fold line, 561 11th fold line, 562 12th fold line, 563 13th fold line, 564 14th fold line, 565 15th fold line, 566 16th fold line, 571 1st overlap area, 572, 572A 2nd overlap area, 573, 573A 3rd overlap area, 574, 574A 4th overlap area, 575 5th overlap area, 576 6th overlap area, 577 7th overlap area, 578 8th overlap area, 579 9th overlap area, 580 10th overlap area.

Claims

1. an electrode assembly having a positive electrode plate and a negative electrode plate; a metal exterior body having an opening and accommodating the electrode assembly and the electrolyte; a sealing plate that seals the opening; a positive electrode terminal electrically connected to the positive electrode plate and attached to the sealing plate; a negative electrode terminal electrically connected to the negative electrode plate and attached to the sealing plate; and an insulating sheet disposed between the electrode body and the exterior body, the exterior body has a bottom facing the opening, a pair of first side walls standing upright from an edge of the bottom and facing each other, and a pair of second side walls standing upright from the edge of the bottom and facing each other, connecting the first side walls, The insulating sheet is a bottom surface portion facing the bottom portion; a first side portion disposed between one of the pair of first side walls and the electrode body; a second side surface portion disposed between the other of the pair of first side walls and the electrode body; a first left piece bent from one lateral end of the first side surface portion and disposed between one of the pair of second side walls and the electrode body; a second left side piece bent from one lateral end of the second side surface portion and disposed between one of the pair of second side walls and the electrode body, at least partially overlapping with the first left side piece; a left bottom piece rising from one lateral end of the bottom surface portion and positioned between one of the pair of second side walls and the electrode body; a first left-side connecting portion provided continuously with each of the first left-side piece and the left-side bottom piece, folded at the boundary between each of the first left-side piece and the left-side bottom piece, and sandwiched between the first left-side piece and the left-side bottom piece; a second left-side connecting portion provided continuously with each of the second left-side piece and the left-side bottom piece, folded at the boundary between each of the second left-side piece and the left-side bottom piece, and sandwiched between the second left-side piece and the left-side bottom piece; the shortest penetration path of the electrolyte solution penetrating from the outside of the insulating sheet into the end of the electrode body that is closest to the bottom side of the exterior body and the ridge line portion on one side of the pair of second side walls is a path that passes through any one of the outer circumferential edge of the first left-side connection portion, the outer circumferential edge of the left-side bottom piece portion, and the outer circumferential edge of the second left-side connection portion; the shortest distance between the portion on the shortest penetration path and the bottom portion is 5 mm or more at any one of the outer periphery of the first left-side connection portion, the outer periphery of the left-side bottom piece portion, and the outer periphery of the second left-side connection portion; a tab portion provided on at least one of the positive electrode plate and the negative electrode plate and extending laterally from the electrode body; Further, a current collector connected to the tab portion is provided. the current collector includes a first region facing the second side wall, a third region positioned closer to the sealing plate than the first region and facing the second side wall, and a second region connecting the first region and the third region, a shortest distance between the first region and the second side wall in a direction perpendicular to the second side wall, in the current collector and the second side wall facing each other, is shorter than a shortest distance between the third region and the second side wall.

2. The insulating sheet is folded to form a cylindrical shape with a bottom, the bottom surface portion has a rectangular shape having a pair of long sides and a pair of short sides perpendicular to the pair of long sides, the first side surface portion is connected to one of the pair of long sides of the bottom surface portion, and a first folding line is formed at a boundary between the bottom surface portion and the first side surface portion, the second side surface portion is connected to the other of the pair of long sides of the bottom surface portion, and a second folding line is formed at the boundary between the bottom surface portion and the second side surface portion, a third folding line is formed at a boundary between the first side surface portion and the first left piece portion, a fourth folding line is formed at a boundary between one of the pair of short sides of the bottom surface portion and the left bottom piece portion, a fifth folding line is formed at a boundary between the second side surface portion and the second left piece portion, a sixth folding line is formed at a boundary between the first left piece portion and the first left connection portion; a seventh folding line is formed at the boundary between the left bottom piece and the first left connection portion; an eighth folding line is formed at the boundary between the left bottom piece and the second left connecting portion; a ninth folding line is formed at a boundary between the second left piece and the second left connection portion, the insulating sheet has, between one of the pair of second side walls and the electrode body, a first overlapping region where the first left side piece and the second left side piece overlap each other, a second overlapping region where the first left side piece, the second left side piece and the left bottom piece overlap each other, a third overlapping region where the first left side piece, the left bottom piece and the first left connecting portion overlap, and a fourth overlapping region where the second left side piece, the left bottom piece and the second left connecting portion overlap, a first communication passage that communicates between the inside and outside of the insulating sheet and has a first open end at the end of each of the first left-side connection portion and the second left-side connection portion on the opening side of the exterior body, the first left-side piece, the second left-side piece, the left bottom piece, the first left-side connection portion, and the second left-side connection portion; The battery according to claim 1 , wherein the first opening end is located at an end position of each of the third overlapping region and the fourth overlapping region on the opening side of the exterior body.

3. 3. The battery according to claim 1, wherein the electrode assembly is a laminated electrode assembly including a plurality of the positive electrode plates and a plurality of the negative electrode plates.

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