Battery and mounting structure thereof

Abstract

To provide a highly reliable battery and mounting structure thereof.SOLUTION: In a battery, a case has an outer surface including a first surface extending in a plane including the first direction, and a second surface connected to one end of the first surface in the first direction and substantially perpendicular to the first surface, and a gas release valve provided on the second surface. The battery also includes an electrode terminal provided on the outside of the first surface of the case, and a current collector provided on the inside of the first surface of the case. The electrode body and the current collector are joined at a first joint, and the current collector and the electrode terminal are joined at a second joint, and at least one of the first joint and the second joint is biased toward the second surface in the first direction.SELECTED DRAWING: Figure 14

Description

[Technical Field]

[0001] The present technology relates to a battery and a mounting structure thereof. [Background technology]

[0002] Batteries with an electrode assembly housed in a case have been known for some time, and have traditionally employed a structure in which a portion of the case is split open to release the contents when the temperature of the electrode assembly rises.

[0003] For example, Japanese Patent Application Laid-Open No. 2022-185087 (Patent Document 1) discloses a structure in which an electrode terminal and a gas release valve are provided on the top surface (sealing plate) of a prismatic secondary battery.

[0004] US Patent Application Publication No. 2023 / 0187770 (Patent Document 2) discloses a structure in which electrode terminals are provided on both side surfaces (sealing plates) of the housing of a prismatic secondary battery, and a gas release valve is provided on the bottom surface of the housing. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-185087 [Patent Document 2] US Patent Application Publication No. 2023 / 0187770 [Patent Document 3] Japanese Patent Application Laid-Open No. 2017-152394 [Patent Document 4] Japanese Patent Application Laid-Open No. 2008-66284 [Patent Document 5] Japanese Patent Application Laid-Open No. 2016-189248 [Patent Document 6] Japanese Patent Publication No. 2020-87514 [Patent Document 7] Japanese Patent Application Laid-Open No. 2003-303581 [Patent Document 8] Japanese Patent Application Publication No. 11-185714 [Patent Document 9] Japanese Patent Application Laid-Open No. 2000-285892 Summary of the Invention [Problem to be solved by the invention]

[0006] In order to improve the reliability of batteries, it is necessary to prevent the electrode assembly from splitting at unintended locations when the temperature rises. From this perspective, there is still room for improvement in conventional batteries.

[0007] An object of the present technology is to provide a highly reliable battery and a mounting structure thereof. [Means for solving the problem]

[0008] The present technology provides the following battery and its mounting structure.

[0009] [1] A battery comprising an electrode body and a case that houses the electrode body, wherein the case has an outer surface including a first surface extending in a plane that includes a first direction, and a second surface that is connected to one end of the first surface in the first direction and is approximately perpendicular to the first surface, and a gas release valve provided on the second surface, wherein the battery further comprises an electrode terminal provided on the outside of the first surface of the case, and a current collector provided on the inside of the first surface of the case, wherein the electrode body and the current collector are joined at a first joint, and the current collector and the electrode terminal are joined at a second joint, and at least one of the first joint and the second joint is biased toward the second surface in the first direction.

[0010] In the present technology, "distributed toward the second surface" is not limited to the case where the first or second joint is located only on the second surface side of the center in the first direction, but also includes the case where a portion of the first or second joint is located on the opposite side of the second surface, but more than half (preferably 60% or more, more preferably 70% or more, and even more preferably 80% or more or 90% or more) of the area of ​​the first or second joint (projected area onto the first surface) is located on the second surface side.

[0011] [2] The battery according to [1], wherein the gas release valve is provided only at one location in the center of the second surface in a second direction substantially perpendicular to the first surface.

[0012] [3] The battery described in [1], wherein the electrode body has a main body portion and a tab portion protruding from the main body portion toward the first surface at an end portion in a second direction substantially perpendicular to the first surface, and the first joint portion is formed between the tab portion and the current collector.

[0013] [4] The battery according to [3], wherein the first joint is formed by laser welding.

[0014] [5] The battery according to [3] or [4], wherein the second joint is formed by crimping.

[0015] [6] The battery according to any one of [1] to [5], wherein the electrode assembly includes a positive electrode, a negative electrode laminated on the positive electrode, and a separator provided between the positive electrode and the negative electrode.

[0016] [7] The battery described in [6], wherein the outer surface of the case further includes a third surface connected to the other end of the first surface in the first direction and facing the second surface in the first direction, the separator is arranged to protrude more toward the second surface side and the third surface side than the positive electrode and the negative electrode in the first direction, and the amount of protrusion of the separator relative to the positive electrode and the negative electrode in the first direction is greater on the second surface side than on the third surface side.

[0017] [8] A battery described in any one of [1] to [6], wherein the outer surface of the case further includes a third surface connected to the other end of the first surface in the first direction and facing the second surface in the first direction, and wherein, when the distance between the second surface and the third surface in the first direction is H, the first joint portion is formed in an area whose distance from the second surface in the first direction is 1 / 10H or more and 4 / 10H or less.

[0018] [9] The battery according to any one of [1] to [8], wherein the conductive area of ​​the first joint is less than 0.3 times the conductive area of ​​the current collector.

[0019]

[10] The battery according to any one of [1] to [8], wherein the conductive area of ​​the second joint is less than 0.2 times the conductive area of ​​the current collector.

[0020]

[11] A battery described in any one of [1] to

[10] , wherein in the case, the thickness of the first plate-shaped portion constituting the first surface is more than three times the thickness of the second plate-shaped portion constituting the second surface.

[0021]

[12] The battery mounting structure according to any one of [1] to

[11] , wherein the second surface of the case is disposed downward. [Effects of the Invention]

[0022] According to the battery of the present technology, by distributing at least one of the first and second joints toward the second surface in the first direction, it is possible to bring at least one of the first and second joints closer to the gas release valve. The first and second joints tend to have a small conductive area, which makes it easy for the temperature of the electrode assembly located nearby to rise. According to the present technology, the part of the electrode assembly where the temperature is likely to rise and the gas release valve can be brought closer to each other, thereby preventing rupture at an unintended position when the temperature rises, and providing a highly reliable battery.

[0023] According to the battery mounting structure of the present technology, by arranging the second surface on which the gas release valve is formed on the lower side, the electrolyte can be preferentially released through the ruptured gas release valve. As a result, the increase in internal pressure due to gasification of the electrolyte can be effectively suppressed, and the reliability of the battery can be further improved. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a front view showing the configuration of a secondary battery according to one embodiment. [Figure 2] 2 is a diagram showing the secondary battery shown in FIG. 1 as viewed from the direction of arrow II. [Figure 3] 3 is a diagram showing the secondary battery shown in FIG. 1 as viewed from the direction of arrow III. [Figure 4] 4 is a diagram showing the secondary battery shown in FIG. 1 as viewed from the direction of arrow IV. FIG. [Figure 5] 2 is a diagram showing the secondary battery shown in FIG. 1 as viewed from the direction of arrow V. FIG. [Figure 6] FIG. 2 is a front cross-sectional view of the secondary battery shown in FIG. [Figure 7] FIG. [Figure 8] FIG. [Figure 9] FIG. [Figure 10] FIG. [Figure 11] 1. FIG. 1 is a cross-sectional view of the secondary battery taken along the line XI-XI in FIG. [Figure 12] 1. FIG. 2 is a cross-sectional view of the secondary battery shown in FIG. [Figure 13] 1 is a flowchart showing a method for manufacturing a secondary battery according to one embodiment. [Figure 14] FIG. 2 is a diagram schematically illustrating an example of the arrangement of first and second bonding portions in a secondary battery according to one embodiment. [Figure 15] FIG. 2 is a perspective view illustrating a first joint according to an example. [Figure 16] FIG. 10 is a perspective view illustrating a second joint according to an example. [Figure 17] 17 is a cross-sectional view taken along the line XVII-XVII in FIG. 16. DETAILED DESCRIPTION OF THE INVENTION

[0025] 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.

[0026] In the embodiments described below, when numbers, amounts, etc. are mentioned, the scope of the present technology is not necessarily limited to those numbers, amounts, etc., unless otherwise specified. Furthermore, in the following embodiments, each component is not necessarily essential to the present technology, unless otherwise specified. Furthermore, the present technology is not necessarily limited to those that achieve all of the effects and advantages mentioned in the present embodiments.

[0027] In this specification, the terms "comprise," "include," and "have" are open-ended. That is, when a certain feature is included, other features may or may not be included.

[0028] Furthermore, when geometric terms and terms expressing positional and directional relationships are used in this specification, such as "parallel," "orthogonal," "45° diagonal," "coaxial," and "along," these terms allow for manufacturing errors and slight variations. When terms expressing relative positional relationships, such as "upper side" and "lower side," are used in this specification, these terms are used to indicate relative positional relationships in a single state, and the relative positional relationships can be reversed or rotated to any angle depending on the installation direction of each mechanism (for example, by turning the entire mechanism upside down).

[0029] In this specification, the term "battery" is not limited to lithium-ion batteries, but may include other batteries such as nickel-metal hydride batteries and sodium-ion batteries. In this specification, the term "electrode" may collectively refer to a positive electrode and a negative electrode.

[0030] In the drawings, if the electrode body of the secondary battery is a laminated electrode body, the longitudinal direction of the laminated surface is the X direction, and if the electrode body is a wound electrode body, the direction along the winding axis is the X direction. The shorter side direction of the electrode body as viewed from the X direction is the Y direction, and the longer side direction of the electrode body as viewed from the X direction is the Z direction. To facilitate understanding of the invention, the dimensions of each component in the drawings may be slightly different from the actual dimensions.

[0031] In this specification, the first direction, the Z direction, may be referred to as the "height direction" of the secondary battery, electrode body, and case body, the second direction, the X direction, may be referred to as the "width direction" of the secondary battery, electrode body, and case body, and the third direction, the Y direction, may be referred to as the "thickness direction" of the secondary battery, electrode body, and case body.

[0032] (Overall battery configuration) Fig. 1 is a front view of a secondary battery 1 according to an embodiment. Figs. 2 to 5 are views of the secondary battery 1 shown in Fig. 1 as viewed from the directions of arrows II, III, IV, and V, respectively. Fig. 6 is a front cross-sectional view of the secondary battery 1 shown in Fig. 1.

[0033] The secondary battery 1 can be mounted in an electric vehicle (BEV: Battery Electric Vehicle), a plug-in hybrid electric vehicle (PHEV: Plug-in Hybrid Electric Vehicle), a hybrid electric vehicle (HEV: Hybrid Electric Vehicle), etc. However, the use of the secondary battery 1 is not limited to being mounted in a vehicle.

[0034] 1 to 6, the secondary battery 1 includes a case 100, an electrode assembly 200, an electrode terminal 300, and a current collector 400. The case 100 includes a case body 110, a sealing plate 120 (first sealing plate), and a sealing plate 130 (second sealing plate).

[0035] When configuring a battery pack including the secondary batteries 1, multiple secondary batteries 1 are stacked in their thickness direction. The stacked secondary batteries 1 may be constrained in the stacking direction (Y direction) by a constraining member to form a battery module, or multiple secondary batteries 1 may be housed in a battery pack case without using a constraining member.

[0036] The case body 110 is made of a cylindrical, preferably rectangular, member. This results in a rectangular secondary battery 1. The case body 110 is made of metal. Specifically, the case body 110 is made of aluminum, an aluminum alloy, iron, an iron alloy, or the like.

[0037] 1 and 2, sealing plates 120 and 130 are provided at both ends of the case body. Case body 110 can be formed into a rectangular tube shape, for example, by abutting the edges of bent plate-like members (joint 115 shown in FIG. 2) and joining them together (for example, by laser welding). The corners of the "rectangular tube" may be rounded.

[0038] In this embodiment, the case body 110 is formed so that it is longer in the width direction (X direction) of the secondary battery 1 than in the thickness direction (Y direction) and height direction (Z direction) of the secondary battery 1. The dimension (width) of the case body 110 in the X direction is preferably about 30 cm or more. This allows for the construction of a relatively large (high-capacity) secondary battery 1. The dimension (height) of the case body 110 in the Z direction is preferably about 20 cm or less, more preferably about 15 cm or less, and even more preferably about 10 cm or less. This allows for the construction of a relatively low-height secondary battery 1, which improves, for example, the mountability in a vehicle.

[0039] The case main body 110 includes a pair of first side surface portions 111 and a pair of second side surface portions 112. The pair of first side surface portions 111 constitute part of the side surfaces of the case 100. The pair of second side surface portions 112 constitute a bottom surface portion 112A and a top surface portion 112B of the case 100. The pair of first side surface portions 111 and the pair of second side surface portions 112 are arranged to intersect with each other. The pair of first side surface portions 111 and the pair of second side surface portions 112 are connected at their respective ends. It is desirable that each of the pair of first side surface portions 111 has a larger area than each of the pair of second side surface portions 112.

[0040] As shown in Fig. 5, a gas release valve 150 is provided on a bottom surface 112A, which is one of the pair of second side surface portions 112. In the example of Fig. 5, the gas release valve 150 is provided in only one location near the center in the width direction (X direction) of the secondary battery 1. The shape and arrangement of the gas release valve 150 on the bottom surface 112A can be changed as appropriate.

[0041] The thickness of the plate-like member in the gas release valve 150 is thinner than the thickness of the plate-like members of the case body 110 other than the gas release valve 150. As a result, when the pressure inside the case 100 reaches or exceeds a predetermined value, the gas release valve 150 breaks preferentially compared to other parts of the case body 110, and releases gas inside the case 100 to the outside.

[0042] 2, a joint 115 is formed on the top surface 112B, which is the other of the pair of second side surface portions 112. The joint 115 extends in the width direction (X direction) of the secondary battery 1. At the joint 115, the edges of the plate-like members that make up the case body 110 are joined together.

[0043] 3, an opening 113 (first opening) is provided at an end of a first side in the X direction of case body 110. Opening 113 is sealed by sealing plate 120. Opening 113 and sealing plate 120 have a generally rectangular shape with the Y direction as the short side direction and the Z direction as the long side direction. The generally rectangular shape includes a rectangular shape or a substantially rectangular shape such as a rectangular shape with rounded corners.

[0044] A negative electrode terminal 301 is provided on the sealing plate 120 (first sealing plate). The position of the negative electrode terminal 301 can be changed as appropriate.

[0045] 4, an opening 114 (second opening) is provided at the end of a second side of case body 110 opposite the first side in the X direction. That is, opening 114 is located at the end opposite opening 113, and openings 113 and 114 face each other. Opening 114 is sealed by sealing plate 130. Opening 114 and sealing plate 130 have a substantially rectangular shape with the Y direction as the short side direction and the Z direction as the long side direction.

[0046] A positive electrode terminal 302 and a liquid injection hole 130A are provided on the sealing plate 130 (second sealing plate). The positions of the positive electrode terminal 302 and the liquid injection hole 130A can be changed as appropriate.

[0047] The sealing plates 120 and 130 are made of metal. Specifically, the sealing plates 120 and 130 are made of aluminum, an aluminum alloy, iron, an iron alloy, or the like.

[0048] The negative electrode terminal 301 (first electrode terminal) is electrically connected to the negative electrode of the electrode body 200. The negative electrode terminal 301 is attached to the sealing plate 120, that is, the case 100.

[0049] The positive electrode terminal 302 (second electrode terminal) is electrically connected to the positive electrode of the electrode body 200. The positive electrode terminal 302 is attached to the sealing plate 130, that is, the case 100.

[0050] The negative electrode terminal 301 is made of a conductive material (more specifically, a metal), and may be made of, for example, copper or a copper alloy. The outer surface of the negative electrode terminal 301 may be provided with a portion or layer made of aluminum or an aluminum alloy.

[0051] The positive terminal 302 is made of a conductive material (more specifically, a metal), and may be made of, for example, aluminum or an aluminum alloy.

[0052] The liquid inlet 130A is sealed with a sealing member (not shown), which may be, for example, a blind rivet or other metal member.

[0053] The electrode assembly 200 is a flat electrode assembly in which positive and negative electrode plates, which will be described later, are stacked. Specifically, the electrode assembly 200 is a laminated electrode assembly in which multiple positive and negative electrode plates are alternately stacked with a separator 800, which will be described later, interposed therebetween. However, in this specification, the term "electrode assembly" is not limited to a laminated electrode assembly, but may also refer to a wound electrode assembly in which strip-shaped positive and negative electrode plates are wound together with a strip-shaped separator interposed therebetween. The separator 800 can be made of, for example, a polyolefin microporous membrane.

[0054] As shown in Fig. 6, the case 100 houses the electrode assembly 200. Fig. 6 illustrates a first electrode assembly 201, which will be described later. The first electrode assembly 201 is housed in the case 100 so that its longitudinal direction is parallel to the X direction.

[0055] Specifically, one or more laminated electrode bodies are housed together with an electrolytic solution (electrolyte) inside an insulating sheet 700 (described below) that is placed inside the case 100. The electrolytic solution (nonaqueous electrolytic solution) can be, for example, a nonaqueous solvent in which ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) are mixed in a volume ratio (25°C) of 30:30:40, with LiPF dissolved at a concentration of 1.2 mol / L.

[0056] The first electrode body 201 includes a substantially rectangular main body portion, a negative electrode tab group 220 (first electrode tab group), and a positive electrode tab group 250 (second electrode tab group).

[0057] The main body is composed of a negative electrode plate 210 and a positive electrode plate 240, which will be described later. The negative electrode tab group 220 is located at the end of the first electrode body 201 on the sealing plate 120 side in the X direction with respect to the main body. The positive electrode tab group 250 is located at the end of the first electrode body 201 on the sealing plate 130 side in the X direction with respect to the main body.

[0058] The negative electrode tab group 220 and the positive electrode tab group 250 are formed so as to protrude from the center portion of the electrode body 200 toward the sealing plate 120 or the sealing plate 130, respectively.

[0059] The current collector 400 includes a negative electrode current collector 401 and a positive electrode current collector 402. The electrode assembly 200 is electrically connected to the negative electrode terminal 301 and the positive electrode terminal 302 via the current collector 400.

[0060] The negative electrode current collector 401 is disposed on the sealing plate 120 via a resin insulating member. The negative electrode current collector 401 is electrically connected to the negative electrode tab group 220 and the negative electrode terminal 301. The negative electrode current collector 401 is made of a conductive material (more specifically, a metal), and may be made of, for example, copper or a copper alloy. Details of the negative electrode current collector 401 will be described later.

[0061] The positive electrode current collector 402 is disposed on the sealing plate 130 via a resin insulating member. The positive electrode current collector 402 is electrically connected to the positive electrode tab group 250 and the positive electrode terminal 302. The positive electrode current collector 402 is made of a conductive material (more specifically, a metal), and may be made of, for example, aluminum or an aluminum alloy. Details of the positive electrode current collector 402 will be described later.

[0062] (Configuration of electrode body 200) Fig. 7 is a cross-sectional view of the negative electrode plate 210 (a cross-sectional view taken along line VII-VII in Fig. 8), and Fig. 8 is a front view showing the negative electrode plate 210. As shown in Fig. 7, a negative electrode active material layer 212 is formed on a negative electrode core 211.

[0063] As shown in Fig. 8, a plurality of negative electrode tabs 230 (first electrode tabs) made of negative electrode cores 211 are provided at one end in the width direction of the negative electrode plate 210. When the negative electrode plates 210 are stacked, the plurality of negative electrode tabs 230 are stacked to form a negative electrode tab group 220. The length in the protruding direction of each of the negative electrode tabs 230 of the plurality of negative electrode plates 210 is adjusted as appropriate, taking into consideration the state in which the negative electrode tab group 220 is connected to the negative electrode current collector 401. The shape of the negative electrode tab 230 is not limited to the example shown in Fig. 8.

[0064] Fig. 9 is a cross-sectional view of the positive electrode plate 240 (cross-sectional view taken along line IX-IX in Fig. 10), and Fig. 10 is a front view showing the positive electrode plate 240. As shown in Fig. 9, a positive electrode active material layer 242 is formed on a positive electrode core 241.

[0065] As shown in Fig. 10, a plurality of positive electrode tabs 260 (second electrode tabs) made of positive electrode cores 241 are provided at one end in the width direction of the molded positive electrode plate 240. When the positive electrode plates 240 are stacked, the plurality of positive electrode tabs 260 are stacked to form a positive electrode tab group 250. The length of each of the positive electrode tabs 260 in the protruding direction of the plurality of positive electrode plates 240 is adjusted as appropriate, taking into consideration the state in which the positive electrode tab group 250 is connected to the positive electrode current collector 402. The shape of the positive electrode tab 260 is not limited to the example shown in Fig. 10.

[0066] A positive electrode protective layer 243 is provided at the base of the positive electrode tab 260. The positive electrode protective layer 243 does not necessarily have to be provided at the base of the positive electrode tab 260.

[0067] In a typical example, the thickness of the negative electrode tab 230 (one piece) is smaller than the thickness of the positive electrode tab 260 (one piece). In this case, the thickness of the negative electrode tab group 220 is smaller than the thickness of the positive electrode tab group 250.

[0068] (Connection structure between electrode body 200 and current collector 400) Fig. 11 is a cross-sectional view taken along line XI-XI of the secondary battery shown in Fig. 1. As shown in Fig. 11, the electrode body 200 includes a first electrode body 201 and a second electrode body 202. Each of the first electrode body 201 and the second electrode body 202 includes a positive electrode and a negative electrode. The electrode body 200 may be composed of three or more electrode bodies.

[0069] The electrode body 200 is formed by stacking a first electrode body 201 and a second electrode body 202. The first electrode body 201 and the second electrode body 202 are aligned in the thickness direction (Y direction) of the first electrode body 201 and the second electrode body 202.

[0070] The first electrode body 201 includes a negative electrode tab group 220. The negative electrode tab group 220 is electrically connected to one current collector 410 (negative electrode current collector) at a first end 205 in the X direction. The second electrode body 202 includes a negative electrode tab group 270. The negative electrode tab group 270 is electrically connected to another current collector 410 (negative electrode current collector) at a third end 207 in the X direction.

[0071] The negative electrode tab group 220 has a curved portion 221 and a tip portion 222. The curved portion 221 is a portion of the negative electrode tab group 220 that is curved relative to the tip portion 222 on the side where the first electrode is connected.

[0072] The negative electrode tab group 270 has a curved portion 271 and a tip portion 272. The curved portion 271 is a portion of the negative electrode tab group 270 that is curved relative to the tip portion 272 on the side where the first electrode is connected.

[0073] The negative electrode tab group 220 and the negative electrode tab group 270 are curved in opposite directions so that the tip portions 222, 272 approach each other. In the present embodiment, the tip portions 222, 272 are spaced apart, but this configuration is not limiting, and the tip portions 222, 272 may be in contact with each other.

[0074] The negative electrode current collector 401 electrically connects the negative electrode terminal 301 to the negative electrode tab group 220 and the negative electrode tab group 270. The negative electrode current collector 401 in this embodiment is connected to the negative electrode terminal 301 between the electrode body 200 and the sealing plate 120.

[0075] The negative electrode current collector 401 includes two current collectors, a current collector 410 and a current collector 430 .

[0076] Current collector 410 is a plate-like member. Current collector 410 has its longitudinal direction in the Z direction and its transverse direction in the Y direction. Current collector 430 is a plate-like member. Current collector 430 has its longitudinal direction in the Z direction and its transverse direction in the Y direction. Current collector 410 and current collector 430 are aligned in the X direction. In this way, current collector 410 and current collector 430 are composed of separate parts.

[0077] The negative electrode tab groups 220, 270 are joined to the current collector 410 at first joints 411, which will be described later. The first joints 411 can be formed by, for example, ultrasonic welding, resistance welding, laser welding, caulking, or the like. In the present embodiment, the negative electrode tab group 220 and one current collector 410, and the negative electrode tab group 270 and another current collector 410, are joined by, for example, ultrasonic bonding.

[0078] The current collector 430 is electrically connected to one current collector 410 and another current collector 410. The current collector 430 is connected to the negative electrode terminal 301 at a second joint 431. The connection between the current collector 430 and the negative electrode terminal 301 can be formed by, for example, crimping and / or welding.

[0079] Negative electrode terminal 301 is exposed to the outside of sealing plate 120. Negative electrode terminal 301 is connected to plate-shaped member 303. Negative electrode terminal 301 preferably includes region 301A made of copper or a copper alloy and region 301B made of aluminum or an aluminum alloy, and region 301A made of copper or a copper alloy is preferably connected to current collector 430.

[0080] The plate-shaped member 303 is located outside the sealing plate 120. The plate-shaped member 303 is arranged so as to fit along the sealing plate 120. The plate-shaped member 303 is conductive. The plate-shaped member 303 is arranged to ensure a connection area with a bus bar or the like that electrically connects the secondary battery 1 to another adjacent secondary battery. The connection between the negative electrode terminal 301 and the plate-shaped member 303 can be formed by, for example, laser welding.

[0081] An insulating member 510 is disposed between the plate-shaped member 303 and the sealing plate 120. An insulating member 520 is disposed between the negative electrode terminal 301 and the sealing plate 120. An insulating member 530 is disposed between the current collector 430 and the sealing plate 120.

[0082] However, the negative electrode terminal 301 may be electrically connected to the sealing plate 120. Alternatively, the sealing plate 120 may serve as the negative electrode terminal 301.

[0083] A spacer 600 (first spacer), which will be described later, is disposed between the sealing plate 120 and the main body of the electrode body 200 (excluding the negative electrode tab group 220). The spacer 600 is made of an insulating resin material. The negative electrode tab group 220 passes through the interior of the spacer 600, and is thereby protected by the spacer 600. Note that it is also possible to employ a configuration in which the spacer 600 (first spacer) is not provided.

[0084] A resin insulating sheet 700 (electrode body holder) is disposed between the electrode body 200 and the case body 110. The insulating sheet 700 may be made of, for example, resin. More specifically, the material of the insulating sheet 700 is, for example, polypropylene (PP), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyimide (PI), or polyolefin (PO).

[0085] Fig. 12 is a cross-sectional view taken along the line XII-XII of the secondary battery shown in Fig. 1. The connection structure between the electrode body 200 and the current collector 400 on the positive electrode side of the secondary battery 1 in this embodiment differs from the structure on the negative electrode side in that one current collector 410 and a portion corresponding to the other current collector 410 on the negative electrode side are formed from a single component.

[0086] The first electrode body 201 includes a positive electrode tab group 250. The positive electrode tab group 250 is electrically connected to a current collector 420 (positive electrode current collector) at a second end 206 in the X direction. The second electrode body 202 includes a positive electrode tab group 280. The positive electrode tab group 280 is electrically connected to the current collector 420 (positive electrode current collector) at a fourth end 208 in the X direction.

[0087] The positive electrode tab group 250 has a curved portion 251 and a tip portion 252. The curved portion 251 is a portion of the positive electrode tab group 250 that is curved relative to the tip portion 252 on the side where the second electrode is connected.

[0088] The positive electrode tab group 280 has a curved portion 281 and a tip portion 282. The curved portion 281 is a portion of the positive electrode tab group 280 that is curved relative to the tip portion 282 on the side where the second electrode is connected.

[0089] The positive electrode tab group 250 and the positive electrode tab group 280 are curved in opposite directions so that the tip portions 252, 282 approach each other. In the present embodiment, the tip portions 252, 282 are spaced apart, but this configuration is not limiting, and the tip portions 252, 282 may be in contact with each other.

[0090] The positive electrode current collector 402 electrically connects the positive electrode terminal 302 to the positive electrode tab group 250 and the positive electrode tab group 280. The positive electrode current collector 402 in this embodiment is connected to the positive electrode terminal 302 between the electrode body 200 and the sealing plate 130.

[0091] Positive electrode current collector 402 includes current collector 420 (first current collecting member) and current collector 450 (second current collecting member). Plate 460 is interposed between current collector 420 (first current collecting member) and current collector 450 (second current collecting member) as an insulating member. Current collector 420 and current collector 450 are electrically connected in a cross section different from the cross section shown in the figure.

[0092] Current collector 420 is a plate-like member. Current collector 420 has a longitudinal direction in the Z direction and a lateral direction in the Y direction. Current collector 420 is made up of a single, integrated part.

[0093] The positive electrode tab group 250 and the positive electrode tab group 280 are joined to the current collector 420, which is configured as a single component, at a first joint 421. The first joint 421 can be formed by, for example, ultrasonic welding, resistance welding, laser welding, crimping, or the like. In this embodiment, the positive electrode tab group 250 and the positive electrode tab group 280 are joined to the current collector 420 by, for example, ultrasonic welding.

[0094] Current collector 440 is electrically connected to current collector 420. Current collector 440 is connected to positive electrode terminal 302 at second joint 441. The connection between current collector 440 and positive electrode terminal 302 can be formed by, for example, crimping and / or welding.

[0095] Positive electrode terminal 302 is exposed to the outside of sealing plate 130 and is provided so as to reach current collector 440 of positive electrode current collector 402 provided on the inside surface side of sealing plate 130. Positive electrode terminal 302 is connected to plate-shaped member 304.

[0096] The plate-shaped member 304 is located outside the sealing plate 130. The plate-shaped member 304 is arranged so as to fit along the sealing plate 130. The plate-shaped member 304 is conductive. The plate-shaped member 304 is arranged to ensure a connection area with a bus bar or the like that electrically connects the secondary battery 1 to another adjacent secondary battery. The connection between the positive electrode terminal 302 and the plate-shaped member 304 can be formed by, for example, laser welding.

[0097] An insulating member 510 is disposed between the plate-shaped member 304 and the sealing plate 130. An insulating member 520 is disposed between the positive electrode terminal 302 and the sealing plate 130. An insulating member 470 is disposed between the current collector 440 and the sealing plate 130.

[0098] However, the positive electrode terminal 302 may be electrically connected to the sealing plate 130. Alternatively, the sealing plate 130 may serve as the positive electrode terminal 302.

[0099] (Manufacturing process of secondary battery 1) A method for manufacturing a secondary battery according to this embodiment will be described below. Fig. 13 is a flowchart showing the method for manufacturing a secondary battery according to one embodiment.

[0100] 13, in the method for manufacturing a secondary battery according to the present embodiment, first, a first electrode body 201 and a second electrode body 202 are fabricated (step S1). It is preferable that a portion of the tip of each of the negative electrode tab group 220, the positive electrode tab group 250, the negative electrode tab group 270, and the positive electrode tab group 280 is cut off so that the tip lengths are the same when bundled.

[0101] Thereafter, the negative electrode tab group 220 is joined to one current collector 410 (step S2). Next, the negative electrode tab group 270 is joined to another current collector 410 (step S3). The negative electrode tab groups 220, 270 are joined to the current collector 410 at a first joint 411.

[0102] Next, the positive electrode tab group 250 and the positive electrode tab group 280 are joined to the current collector 420 (step S4). The positive electrode tab groups 250, 280 are joined to the current collector 420 at first joints 421.

[0103] The order of the steps of joining the current collector 410 and the current collector 420 to the first electrode body 201 and the second electrode body 202, respectively, is not limited to the above, and the order may be changed.

[0104] Next, the positive electrode tab group 250 and the positive electrode tab group 280 are folded in the thickness direction (Y direction) of the case body 110, and the first electrode body 201 and the second electrode body 202 are overlapped (step S5).

[0105] The first electrode body 201 and the second electrode body 202 may be directly stacked on top of each other, or another member may be disposed between the first electrode body 201 and the second electrode body 202. Furthermore, the first electrode body 201 and the second electrode body 202 may or may not be fixed by tape or the like.

[0106] Thereafter, the one current collector 410 and the other current collector 410 are electrically connected to the negative electrode terminal 301 via the current collector 430 (step S7). Note that step S7 can also be performed before step S6.

[0107] Next, after the first electrode body 201 and the second electrode body 202 are stacked together, the first electrode body 201 and the second electrode body 202 are inserted into the case body 110 through the opening 113, with the current collector 420 side first (step S8).

[0108] Thereafter, the current collector 420 is electrically connected to the positive electrode terminal 302 (step S9). Furthermore, the sealing plates 120 and 130 are joined to the case body 110 (step S10). As a result, the first electrode body 201 and the second electrode body 202 are housed in the case 100.

[0109] After the above steps, inspections such as a leak inspection are performed (step S11). After the leak inspection, the secondary battery 1 is dried to remove moisture from inside the case 100. Then, electrolyte is injected into the inside of the case 100 through the liquid injection hole 130A. After that, degassing charging is performed. The liquid injection hole 130A may be temporarily sealed during degassing charging. After that, the liquid injection hole 130A is sealed, and the secondary battery 1 is completed.

[0110] (Arrangement of first joints 411, 421 and second joints 431, 441) FIG. 14 is a diagram schematically illustrating an example of the arrangement of the first bonding portions 411, 421 and the second bonding portions 431, 441 in the secondary battery 1. As shown in FIG.

[0111] 14, the internal space of the case 100 contains an electrode assembly 200, a current collector 400, and an electrolyte solution 900. An electrode terminal 300 is provided on the outer surface of the case 100.

[0112] The outer surface of the case 100 includes sealing plates 120, 130 (first surfaces) extending in the direction of the YZ plane including the Z direction (first direction), and a bottom surface portion 112A (second surface) connected to one end of the sealing plates 120, 130 in the Z direction and approximately perpendicular to the sealing plates 120, 130.

[0113] 14, the first joints 411, 421 joining the electrode body 200 and the current collector 400 are unevenly located toward the bottom surface 112A in the Z direction. Similarly, the second joints 431, 441 joining the current collector 400 and the electrode terminal 300 are unevenly located toward the bottom surface 112A in the Z direction.

[0114] More specifically, the first joints 411 and 421 and the second joints 431 and 441 are located in an area closer to the bottom surface 112A than the center of the case 100 in the height direction (O1 in FIG. 14).

[0115] The first joints 411, 421 and the second joints 431, 441 are formed by joining parts of multiple conductive members by welding, crimping, or the like. Therefore, the electrical conduction areas of the first joints 411, 421 and the second joints 431, 441 tend to be relatively small compared to other parts. Therefore, the temperature of the electrode body 200 tends to rise in the vicinity of the first joints 411, 421 and the second joints 431, 441.

[0116] When the temperature of the electrode body 200 rises excessively, the electrolyte 900 gasifies, causing an increase in the internal pressure of the case 100. When the internal pressure of the case 100 reaches a predetermined value or higher, the gas release valve 150 ruptures. At this time, it is required that the gas release valve 150 be reliably ruptured without rupturing any parts other than the gas release valve 150.

[0117] In the secondary battery 1 according to the present embodiment, the first bonding portions 411, 421 and the second bonding portions 431, 441 are unevenly located on the bottom surface portion 112A side, and therefore the first bonding portions 411, 421 and the second bonding portions 431, 441 are located close to the gas release valve 150. This allows the portion of the electrode body 200 where the temperature is likely to rise and the gas release valve 150 to be closer to each other, thereby preventing the electrode body 200 from cracking at an unintended position when the temperature rises.

[0118] When the secondary battery 1 is modularized, the first side surface portion 111 of the case body 110 is in contact with the first side surface portion 111 of an adjacent secondary battery 1, and is therefore unlikely to bulge. Therefore, the load due to an increase in gas pressure tends to be concentrated on the sealing plates 120, 130 and the second side surface portion 112 (bottom surface portion 112A and top surface portion 112B) of the case body 110. Of these, from the viewpoint of reliably suppressing cracking of the sealing plates 120, 130 (first surface), it is preferable that the thickness of the sealing plates 120, 130 (first plate-shaped portion) be greater than the thickness of the case body 110 (second plate-shaped portion) that constitutes the bottom surface portion 112A (second surface) (more preferably, greater than about three times the thickness of the case body 110). However, the scope of the present technology is not limited thereto.

[0119] When the secondary battery 1 shown in FIG. 14 is mounted in a vehicle, the secondary battery 1 can be mounted so that the bottom surface 112A of the case 100 is positioned downward. By positioning the bottom surface 112A on which the gas release valve 150 is formed downward in this manner, the electrolytic solution 900 can be preferentially discharged through the opened gas release valve 150. Therefore, an increase in internal pressure due to gasification of the electrolytic solution 900 can be effectively suppressed. However, the mounting structure of the secondary battery 1 according to the present technology is not limited to this.

[0120] More specifically, when the overall height of the case 100 (the distance from the bottom surface 112A to the top surface 112B) is H, the first joints 411, 421 and the second joints 431, 441 are preferably formed in an area whose distance from the bottom surface 112A is equal to or greater than 1 / 10H and equal to or less than 4 / 10H. However, the scope of the present technology is not limited to this.

[0121] 14, the electrode body 200 is a laminated electrode body, and the separator 800 is provided so as to protrude in the Z direction toward the bottom surface 112A (second surface) and the top surface 112B (third surface) further than the negative electrode plate 210 and the positive electrode plate 240. The amount of protrusion of the separator 800 in the Z direction relative to the negative electrode plate 210 and the positive electrode plate 240 is greater on the bottom surface 112A side than on the top surface 112B side.

[0122] By making the separators 800 protrude beyond the negative electrode plate 210 and the positive electrode plate 240, a flow path for the electrolyte solution 900 can be formed between the multiple separators 800. By making the separators 800 protrude relatively far from the bottom surface portion 112A side, a large flow path area for the electrolyte solution 900 can be secured on the bottom surface portion 112A side, and the fluidity of the electrolyte solution 900 can be increased, making it easier to discharge the electrolyte solution 900 from the gas discharge valve 150. By accelerating the discharge of the electrolyte solution 900, an increase in the internal pressure of the case 100 can be effectively suppressed. However, the scope of the present technology is not limited to this.

[0123] Figure 14 shows an example in which the entire first joint portions 411, 421 and the second joint portions 431, 441 are located in an area closer to the bottom surface portion 112A than the center of the height direction of the case 100 (O1 in Figure 14). However, the scope of the present technology is not limited to this, and also includes cases in which a portion of the first joint portions 411, 421 and the second joint portions 431, 441 are on the top surface portion 112B side, but more than half (preferably 60% or more, more preferably 70% or more, and even more preferably 80% or more or 90% or more) of the first joint portions 411, 421 and the second joint portions 431, 441 (projected area onto the sealing plates 120, 130) are on the bottom surface portion 112A side.

[0124] In Figure 14, an example is shown in which both the first joints 411, 421 and the second joints 431, 441 are biased toward the bottom surface 112A, but the scope of the present technology is not limited to this and also includes cases in which only one of the first joints 411, 421 and the second joints 431, 441 is biased toward the bottom surface 112A.

[0125] In Figure 14, an example is shown in which the first joints 411, 421 and the second joints 431, 441 are biased toward the bottom surface 112A on both the negative electrode side and the positive electrode side, but the scope of the present technology is not limited to this and also includes a case in which at least one of the first joints 411, 421 and the second joints 431, 441 is biased toward the bottom surface 112A on only one of the negative electrode side and the positive electrode side.

[0126] Furthermore, in the present embodiment, an example has been shown in which the negative electrode tab groups 220, 270 and the positive electrode tab groups 250, 280 are joined to the current collector 400, but the scope of the present technology is not limited to this, and an electrode body that does not have a tab portion may also be used.

[0127] Fig. 15 is a perspective view showing an example of a first joint 411. In the example of Fig. 15, the first joint 411 is formed by welding. In the example, the conduction area of ​​the first joint 411 (welded portion) is smaller than about 0.3 times the conduction area of ​​the current collector 410 (the area of ​​cross section 410S in Fig. 15).

[0128] Fig. 16 is a perspective view showing an example of the second joint 431, and Fig. 17 is a cross-sectional view taken along line XVII-XVII of Fig. 16. In the examples of Figs. 16 and 17, the second joint 431 is formed by circumferential welding. In one example, the conduction area of ​​the second joint 431 (welded portion) is smaller than approximately 0.2 times the conduction area of ​​the current collector 430 (the area of ​​cross section 430S in Fig. 16).

[0129] 15 to 17 show examples in which the cross-sectional area of ​​the current collectors 410, 430 is constant, but there are also cases in which the cross-sectional area of ​​the current collectors 410, 430 varies in the longitudinal direction. In this case, the smallest value of the cross-sectional area of ​​the current collectors 410, 430 in the portions other than the first joint portion 411 and the second joint portion 431, among the cross-sectional areas that vary in the longitudinal direction, is the "conduction area of ​​the current collectors 410, 430."

[0130] 15 to 17, when the conductive area of ​​the first joint 411 and the second joint 431 is smaller than the conductive area of ​​the current collectors 410, 430, the temperature of the electrode assembly 200 is likely to rise around the first joint 411 and the second joint 431. In the secondary battery 1 according to the present embodiment, the first joint 411 and the second joint 431 are formed in positions close to the gas release valve 150, so that the gas release valve 150 can be reliably cleaved when the temperature of the electrode assembly 200 rises.

[0131] However, the scope of the present technology is not limited to the examples shown in FIGS.

[0132] Although the embodiments of the present technology have been described above, the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present technology is defined by the claims, and it is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0133] 1 secondary battery, 100 case, 110 case body, 111 first side portion, 112 second side portion, 112A bottom portion, 112B upper surface portion, 113, 114 opening, 115 joint portion, 120, 130 sealing plate, 130A liquid injection hole, 150 gas release valve, 200 electrode body, 201 first electrode body, 202 second electrode body, 205 first end portion, 206 second end portion, 207 third end portion, 208 fourth end portion, 210 negative electrode plate, 211 negative electrode core body, 212 negative electrode active material layer, 220, 270 negative electrode tab group, 221, 271 curved portion, 222, 272 tip portion, 230 negative electrode tab, 240 positive electrode plate, 241 positive electrode core body, 242 Positive electrode active material layer, 243 positive electrode protective layer, 250, 280 positive electrode tab group, 251, 281 curved portion, 252, 282 tip portion, 260 positive electrode tab, 300 electrode terminal, 301 negative electrode terminal, 301A, 301B region, 302 positive electrode terminal, 303, 304 plate-shaped member, 400, 410, 420, 430, 440, 450 current collector, 401 negative electrode current collector, 402 positive electrode current collector, 411, 421 first joint portion, 431, 441 second joint portion, 460 plate, 470, 510, 520, 530 insulating member, 600 spacer, 700 insulating sheet, 800 separator, 900 electrolyte.

Claims

1. An electrode body; A battery comprising a case that houses the electrode assembly, the case has an outer surface including a first surface extending in a plane including a first direction, and a second surface connected to one end of the first surface in the first direction and substantially perpendicular to the first surface, and a gas exhaust valve provided on the second surface; The battery comprises: an electrode terminal provided on the outer side of the first surface of the case; a current collector provided on the inside of the first surface of the case, the electrode body and the current collector are joined at a first joint, the current collector and the electrode terminal are joined at a second joint, A battery, wherein at least one of the first joint portion and the second joint portion is biased toward the second surface side in the first direction.

2. The battery according to claim 1 , wherein the gas release valve is provided at only one location in the center of the second surface in a second direction substantially perpendicular to the first surface.

3. the electrode body has a main body portion and a tab portion that protrudes from the main body portion toward the first surface at an end portion in a second direction that is substantially perpendicular to the first surface, The battery of claim 1 , wherein the first joint is formed between the tab portion and the current collector.

4. The battery of claim 3 , wherein the first joint is formed by laser welding.

5. The battery according to claim 3 or 4, wherein the second joint portion is formed by caulking.

6. The battery according to claim 1 , wherein the electrode assembly includes a positive electrode, a negative electrode laminated on the positive electrode, and a separator provided between the positive electrode and the negative electrode.

7. the outer surface of the case further includes a third surface connected to the other end of the first surface in the first direction and facing the second surface in the first direction, the separator is provided so as to protrude toward the second surface side and the third surface side beyond the positive electrode and the negative electrode in the first direction, The battery according to claim 6 , wherein the separator protrudes in the first direction from the positive electrode and the negative electrode by a larger amount on the second surface side than on the third surface side.

8. the outer surface of the case further includes a third surface connected to the other end of the first surface in the first direction and facing the second surface in the first direction, 5. The battery according to claim 1, wherein when a distance between the second surface and the third surface in the first direction is H, the first joint portion is formed in a region where the distance from the second surface in the first direction is 1 / 10H or more and 4 / 10H or less.

9. The battery according to claim 1 , wherein the conductive area of ​​the first joint is smaller than 0.3 times the conductive area of ​​the current collector.

10. The battery according to claim 1 , wherein the conductive area of ​​the second joint portion is smaller than 0.2 times the conductive area of ​​the current collector.

11. 5. The battery according to claim 1, wherein in the case, the thickness of the first plate-shaped portion constituting the first surface is more than three times the thickness of the second plate-shaped portion constituting the second surface.

12. The battery mounting structure according to any one of claims 1 to 4, A battery mounting structure in which the second surface of the case is disposed downward.

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