Secondary battery

Abstract

To secure an electrolyte filling property and suppress increase of the distance between electrode plates.SOLUTION: A first electrode tab group 250 is arranged to be dislocated to an end part E1 on a first side from the center of an electrode 200 in a longer direction of a first surface 120. In the first surface 120, a liquid filling hole 124 is provided near an end part E2 on a second side, which is the opposite side to the side where the end part E1 on the first side is located, from the center of the electrode part 200 in the longer direction. A cover member 500 includes a first part 510 and a pair of second parts 520. The first part 510 faces the liquid filling hold 124 in the first direction. A pair of second parts 520 hold an electrode body 200 in a shorter direction of the first surface 120.SELECTED DRAWING: Figure 14

Description

[Technical field]

[0001] The present technology relates to a secondary battery. [Background technology]

[0002] Prior art documents disclosing power batteries include U.S. Patent No. 11489221 (Patent Document 1), which discloses a configuration in which an electrode body is protected from the injection of electrolyte by a blocking member when electrolyte is injected into a case from an injection hole. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Pat. No. 1,148,921 Summary of the Invention [Problem to be solved by the invention]

[0004] When the secondary battery is provided with a cover member for protecting the electrode assembly from the injection of electrolyte, there is room for ensuring the injection of electrolyte while suppressing an increase in the distance between the electrodes in the electrode assembly.

[0005] The present technology has been made to solve the above-mentioned problems, and aims to provide a secondary battery that can simultaneously ensure the pourability of electrolyte and suppress an increase in the distance between the electrodes in the electrode body. [Means for solving the problem]

[0006] A secondary battery based on the present technology includes an electrode body, a case, and a cover member. The electrode body includes a first electrode and a second electrode having a polarity different from that of the first electrode. The case accommodates the electrode body. The cover member covers a part of the electrode body. The electrode body includes a first electrode tab group and a second electrode tab group. The first electrode tab group is disposed at one end in a first direction and is electrically connected to the first electrode. The second electrode tab group is disposed at the other end opposite to the one end in the first direction and is electrically connected to the second electrode. The case includes a first surface. The first surface faces the electrode body in the first direction and is located on the first electrode tab group side. The first surface has a shape having a longitudinal direction and a lateral direction that intersect with each other when viewed from the first direction. The first electrode tab group is disposed shifted from the center of the electrode body to the end side of the first side in the longitudinal direction of the first surface. The first surface has a liquid inlet provided on a second end portion located on the opposite side from the center of the electrode body in the longitudinal direction to the first end portion. The cover member includes a first portion and a pair of second portions. The first portion faces the liquid inlet port in the first direction. The pair of second portions sandwich the electrode body in the short direction of the first surface. Effect of the Invention

[0007] According to the present technology, it is possible to ensure the pourability of the electrolyte while suppressing an increase in the distance between the electrodes in the electrode assembly. [Brief description of the drawings]

[0008] [Figure 1] 1 is a front view showing a configuration of a secondary battery according to an embodiment of the present technology; [Diagram 2] 2 is a diagram showing the secondary battery shown in FIG. 1 as viewed from the direction of arrow II. [Diagram 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. [Diagram 5] 2 is a front cross-sectional view of the secondary battery shown in FIG. [Figure 6]FIG. 2 is a front view showing a positive electrode original plate before the positive electrode plate is formed. [Figure 7] 7 is a cross-sectional view taken along line VII-VII of the positive electrode plate shown in FIG. 6. [Figure 8] FIG. 2 is a front view showing a positive electrode plate formed from a positive electrode original plate. [Figure 9] FIG. 2 is a front view showing a negative electrode original plate before the negative electrode plate is formed. [Figure 10] 10 is a cross-sectional view taken along the line XX in FIG. 9 . [Figure 11] FIG. 2 is a front view showing a negative electrode plate formed from the negative electrode original plate. [Figure 12] FIG. 2 is a perspective view showing the configuration of an electrode body in the present embodiment. [Figure 13] FIG. 2 is a perspective view showing a configuration of a cover member in the present embodiment. [Figure 14] 5 is a cross-sectional view showing the positional relationship of a cover member with respect to an electrode body and a liquid inlet. FIG. [Figure 15] 4 is a cross-sectional view showing a configuration of a cover member in the present embodiment. FIG. [Figure 16] 2 is a cross-sectional view showing the configuration of an electrode body in the present embodiment. FIG. [Figure 17] 4 is a cross-sectional view showing the positional relationship of a cover member with respect to an electrode body. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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 will not be repeated.

[0010] In the embodiments described below, when referring to the number, amount, etc., the scope of the present technology is not necessarily limited to the number, amount, etc., unless otherwise specified. In addition, in the following embodiments, each component is not necessarily essential to the present technology, unless otherwise specified. In addition, the present technology is not necessarily limited to those that achieve all of the effects and advantages mentioned in the present embodiment.

[0011] In this specification, the words "comprise", "include" and "have" are open-ended, i.e., when a certain configuration is included, other configurations may or may not be included.

[0012] Furthermore, when geometric terms and terms expressing positional and directional relationships, such as "parallel," "orthogonal," "45° diagonal," "coaxial," and "along" are used in this specification, 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 one state, and the relative positional relationships can be inverted or rotated to any angle depending on the installation direction of each mechanism (for example, by turning the entire mechanism upside down).

[0013] In this specification, the term "secondary battery" is not limited to lithium ion batteries, but may include other secondary 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.

[0014] In the drawings, the direction in which the first electrode tab group and the second electrode tab group of the electrode body are arranged is the first direction, i.e., the X direction, the short side direction of the case as viewed from the X direction is the Y direction, and the long side direction of the case as viewed from the X direction is the Z direction. In addition, in order to facilitate understanding of the present technology, the dimensions of each component in the drawings are sometimes shown differently from the actual dimensions.

[0015] (Overall battery configuration) Fig. 1 is a front view of a secondary battery 1 according to the present embodiment. Figs. 2 to 4 are views of the secondary battery 1 shown in Fig. 1 as viewed from the directions of arrows II, III, and IV, respectively. Fig. 5 is a front cross-sectional view of the secondary battery 1 shown in Fig. 1.

[0016] 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 on a vehicle.

[0017] As shown in FIGS. 1 to 5, the secondary battery 1 includes a case 100, an electrode assembly 200, an electrode terminal 300, a current collector 400, and a cover member 500. The case 100 includes an electrode body 200, an electrode terminal 300, a current collector 400, and a cover member 500.

[0018] When configuring an assembled battery including the secondary batteries 1, multiple secondary batteries 1 are stacked in the Y direction. The stacked secondary batteries 1 may be restrained in the stacking direction (Y direction) by a restraining member to form a battery module, or the assembled battery may be directly supported on the side of a battery pack case without using a restraining member.

[0019] The case 100 houses the electrode assembly 200. The case 100 includes a case body 110, a first sealing plate 120, and a second sealing plate .

[0020] 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. When the case body 110 is made of iron or an iron alloy, the case body 110 may be plated with nickel, tin, zinc, or the like.

[0021] 1 and 2, a first sealing plate 120 and a second sealing plate 130 are provided at both ends of the case body. The case body 110 can be formed into a square tube shape, for example, by abutting the edges of bent plate-like members (joints 115 shown in FIG. 2) and joining them together (for example, by laser welding). The corners of the "square tube" may have a rounded shape.

[0022] In this embodiment, the case body 110 is formed to be longer in the X direction of the secondary battery 1 than in the Y and Z directions of the secondary battery 1. The dimension of the case body 110 in the X direction is preferably about 30 cm or more. This allows a relatively large (high capacity) secondary battery 1 to be configured. The dimension 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 a relatively low height secondary battery 1 to be configured, improving the mountability in a vehicle, for example.

[0023] The case 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 face each other in the Y direction. The pair of first side surface portions 111 form part of the side surfaces of the case 100.

[0024] The pair of second side surface portions 112 face each other in the Z direction. The pair of second side surface portions 112 form the bottom surface and the top surface of the case 100.

[0025] The pair of first side surface portions 111 and the pair of second side surface portions 112 are provided so as 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. As in this embodiment, it is desirable that the area of ​​each of the pair of second side surface portions 112 is smaller than the area of ​​each of the pair of first side surface portions 111.

[0026] 2, one 112A of the pair of second side surface portions is formed with a joint 115. The joint 115 extends from the first opening 113 to the second opening 114. That is, the joint 115 extends in the X direction of the secondary battery 1. At the joint 115, the ends of the plate-like members constituting the case body 110 are joined together.

[0027] 3, a first opening 113 is provided at one end of case body 110 in a first direction (X direction). First opening 113 is sealed by a first sealing plate 120. A sealing plate joint 126 is formed in first opening 113 to seal first opening 113. First opening 113 and first sealing plate 120 have a substantially rectangular shape with the Y direction as the short side direction and the Z direction as the long side direction.

[0028] A positive electrode terminal 301 (first electrode terminal), a liquid injection hole 124, and a gas exhaust valve 125 are provided on the first sealing plate 120. The positions of the positive electrode terminal 301, the liquid injection hole 124, and the gas exhaust valve 125 can be changed as appropriate.

[0029] 4, a second opening 114 is provided at the other end of case body 110 in the first direction (X direction). That is, second opening 114 is located at the end opposite to first opening 113. Second opening 114 is sealed by second sealing plate 130. A sealing plate joint 136 is formed in second opening 114 to seal second opening 114. Second opening 114 and second 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.

[0030] A negative electrode terminal 302 (second electrode terminal) and a gas release valve 135 are provided on the second sealing plate 130. The positions of the negative electrode terminal 302 and the gas release valve 135 can be changed as appropriate.

[0031] The first sealing plate 120 and the second sealing plate 130 are made of metal. Specifically, the first sealing plate 120 and the second sealing plate 130 are made of aluminum, an aluminum alloy, iron, an iron alloy, etc. When the first sealing plate 120 and the second sealing plate 130 are made of iron or an iron alloy, the first sealing plate 120 and the second sealing plate 130 may be plated with nickel, tin, zinc, or the like.

[0032] The positive electrode terminal 301 is electrically connected to the positive electrode (first electrode) of the electrode body 200. The positive electrode terminal 301 is attached to the first sealing plate 120, that is, the case 100.

[0033] The negative electrode terminal 302 is electrically connected to the negative electrode (second electrode) of the electrode body 200. The negative electrode terminal 302 is attached to the second sealing plate 130, that is, the case 100.

[0034] The positive electrode terminal 301 is made of a conductive material (more specifically, a metal), and may be made of, for example, aluminum or an aluminum alloy.

[0035] The negative terminal 302 is made of a conductive material (more specifically, a metal), and may be made of, for example, copper or a copper alloy. An outer surface portion of the negative terminal 302 may be provided with a portion or layer made of aluminum or an aluminum alloy.

[0036] The liquid inlet 124 is sealed with a sealing member (not shown). As the sealing member, for example, a blind rivet or other metal members can be used.

[0037] The electrode assembly 200 is a flat-shaped electrode assembly having a positive electrode plate and a negative electrode plate, which will be described later. Specifically, the electrode assembly 200 is a wound-type 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 interposed therebetween.

[0038] 5, case 100 houses electrode assembly 200. Electrode assembly 200 is housed in case 100 so that its winding axis is parallel to the X direction.

[0039] Specifically, one or more wound electrode bodies are housed together with an electrolytic solution (electrolyte) (not shown) inside an insulating sheet (not shown) arranged in the case 100. As the electrolytic solution (non-aqueous electrolytic solution), for example, LiPF6 dissolved at a concentration of 1.2 mol / L in a non-aqueous solvent in which ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are mixed in a volume ratio (25°C) of 30:30:40 can be used. Note that a solid electrolyte may be used instead of the electrolytic solution.

[0040] The electrode body 200 includes a main body portion (a portion in which positive electrode plates and negative electrode plates are stacked with a separator between them), a first electrode tab group 250 (positive electrode tab group), and a second electrode tab group 220 (negative electrode tab group).

[0041] The main body is composed of a positive electrode plate 240 (first electrode) and a negative electrode plate 210 (second electrode), which will be described later.

[0042] The first electrode tab group 250 is disposed at one end in the first direction (X direction) of the electrode body 200. Specifically, the first electrode tab group 250 is located at an end on the first sealing plate 120 side in the X direction with respect to the main body portion.

[0043] The second electrode tab group 220 is disposed at one end of the electrode body 200 in the first direction (X direction) on the opposite side to the other end. Specifically, the second electrode tab group 220 is located at the end on the second sealing plate 130 side in the X direction with respect to the main body portion.

[0044] The first electrode tab group 250 and the second electrode tab group 220 are formed so as to protrude from the central portion of the electrode body 200 towards the first sealing plate 120 or the second sealing plate 130, respectively.

[0045] The first electrode tab group 250 is electrically connected to the first electrodes, and the second electrode tab group 220 is electrically connected to the second electrodes.

[0046] The current collector 400 includes a positive electrode current collector 400A and a negative electrode current collector 400B. The positive electrode current collector 400A and the negative electrode current collector 400B are each made of a plate-shaped member. The electrode assembly 200 is electrically connected to a positive electrode terminal 301 and a negative electrode terminal 302 via the current collector 400.

[0047] The positive electrode current collector 400A is disposed on the first sealing plate 120 via a resin insulating member. The positive electrode current collector 400A is electrically connected to the first electrode tab group 250 and the positive electrode terminal 301. The positive electrode current collector 400A is made of a conductive material (more specifically, a metal), and may be made of, for example, aluminum or an aluminum alloy. The first electrode tab group 250 may be electrically connected to the first sealing plate 120 directly or via the positive electrode current collector 400A. In this case, the first sealing plate 120 may serve as the positive electrode terminal 301.

[0048] The negative electrode current collector 400B is disposed on the second sealing plate 130 via a resin insulating member. The negative electrode current collector 400B is electrically connected to the second electrode tab group 220 and the negative electrode terminal 302. The negative electrode current collector 400B is made of a conductive material (more specifically, a metal), and may be made of, for example, copper or a copper alloy.

[0049] The cover member 500 covers a portion of the electrode body 200. The configuration of the cover member 500 will be described later.

[0050] (Configuration of electrode body 200) Fig. 6 is a front view showing the positive electrode original plate 240S before the positive electrode plate 240 is formed. Fig. 7 is a cross-sectional view taken along line VII-VII of the positive electrode original plate 240S shown in Fig. 6. Fig. 8 is a front view showing the positive electrode plate 240 formed from the positive electrode original plate 240S.

[0051] The positive electrode plate 240, which is the first electrode, is manufactured by processing a positive electrode original plate 240S. As shown in Figures 6 and 7, the positive electrode original plate 240S includes a positive electrode core 241, a positive electrode active material layer 242, and a positive electrode protective layer 243. The positive electrode core 241 is an aluminum foil or an aluminum alloy foil.

[0052] A positive electrode active material layer 242 is formed on both sides of the positive electrode core 241 except for one end portion. The positive electrode active material layer 242 is formed on the positive electrode core 241 by applying a positive electrode active material layer slurry with a die coater.

[0053] 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 approximately 97.5:1:1.5.

[0054] The positive electrode protective layer 243 is in contact with the positive electrode core 241 and is formed at one end in the width direction of the positive electrode active material layer 242. The positive electrode protective layer 243 is formed on the positive electrode core 241 by applying a positive electrode protective layer slurry with a die coater. The positive electrode protective layer 243 has a larger electric resistance than the positive electrode active material layer 242.

[0055] 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 approximately 83:3:14.

[0056] The positive electrode core 241 coated with the positive electrode active material layer slurry and the positive electrode protective layer slurry is dried, and the NMP contained in the positive electrode active material layer slurry and the positive electrode protective layer slurry is removed to form the positive electrode active material layer 242 and the positive electrode protective layer 243. Furthermore, the positive electrode active material layer 242 is compressed to form a positive electrode original plate 240S including the positive electrode core 241, the positive electrode active material layer 242, and the positive electrode protective layer 243. The positive electrode original plate 240S is cut into a predetermined shape to form the positive electrode plate 240. The positive electrode original plate 240S can be cut by laser processing using energy beam irradiation, die processing, cutter processing, or the like.

[0057] As shown in FIG. 8, a plurality of positive electrode tabs 260 made of a positive electrode core 241 are provided at one end in the width direction of the positive electrode plate 240 formed from the positive electrode original plate 240S. When the positive electrode plate 240 is wound, the plurality of positive electrode tabs 260 are stacked to form the first electrode tab group 250. As a result, the first electrode tab group 250 is connected to the positive electrode plate 240 (first electrode). The position and the length in the protruding direction of each of the plurality of positive electrode tabs 260 are appropriately adjusted in consideration of the state in which the first electrode tab group 250 is connected to the positive electrode current collector 400A. The shape of the positive electrode tab 260 is not limited to the one exemplified in FIG. 8.

[0058] A positive electrode protection layer 243 is provided at the base of each of the positive electrode tabs 260. The positive electrode protection layer 243 does not necessarily have to be provided at the base of the positive electrode tab 260.

[0059] Fig. 9 is a front view showing a negative electrode original plate before being formed into a negative electrode plate 210. Fig. 10 is a cross-sectional view taken along line XX of the negative electrode original plate 210S shown in Fig. 9. Fig. 11 is a front view showing a negative electrode plate 210 formed from the negative electrode original plate 210S.

[0060] The negative electrode plate 210, which is the second electrode, has a polarity different from that of the positive electrode plate 240, which is the first electrode. The negative electrode plate 210 is manufactured by processing a negative electrode original plate 210S. As shown in Fig. 9 and Fig. 10, the negative electrode original plate 210S includes a negative electrode core body 211 and a negative electrode active material layer 212. The negative electrode core body 211 is a copper foil or a copper alloy foil.

[0061] A negative electrode active material layer 212 is formed on both sides of the negative electrode core 211 except for one end portion. The negative electrode active material layer 212 is formed by applying a negative electrode active material layer slurry with a die coater.

[0062] 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 approximately 98:1:1.

[0063] The negative electrode core 211 coated with the negative electrode active material layer slurry is dried to remove water contained in the negative electrode active material layer slurry, thereby forming the negative electrode active material layer 212. Furthermore, the negative electrode active material layer 212 is compressed to form a negative electrode original plate 210S including the negative electrode core 211 and the negative electrode active material layer 212. The negative electrode original plate 210S is cut into a predetermined shape to form the negative electrode plate 210. The negative electrode original plate 210S can be cut by laser processing using energy beam irradiation, die processing, cutter processing, or the like.

[0064] As shown in FIG. 11, a plurality of negative electrode tabs 230 made of a negative electrode core 211 are provided at one end in the width direction of a negative electrode plate 210 formed from a negative electrode original plate 210S. When the negative electrode plate 210 is wound, the plurality of negative electrode tabs 230 are stacked to form a second electrode tab group 220. As a result, the second electrode tab group 220 is connected to the negative electrode plate 210 (second electrode). The position and length in the protruding direction of each of the plurality of negative electrode tabs 230 are appropriately adjusted in consideration of the state in which the second electrode tab group 220 is connected to the negative electrode current collector 400B. The shape of the negative electrode tab 230 is not limited to the one exemplified in FIG. 11.

[0065] 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 second electrode tab group 220 is smaller than the thickness of the first electrode tab group 250.

[0066] FIG. 12 is a perspective view showing the configuration of the electrode body in the present embodiment.

[0067] As shown in FIG. 12, the electrode body 200 in this embodiment is wound with the separator 270 sandwiched between the positive electrode plate 240 and the negative electrode plate 210. Specifically, the positive electrode plate 240, the negative electrode plate 210, and the separator 270 are wound around a winding axis A extending in the X direction. However, in this specification, the "electrode body" is not limited to a wound electrode body, and may be a laminated electrode body in which multiple positive electrode plates and multiple negative electrode plates are alternately laminated. The strip-shaped separator 270 can be composed of, for example, a polyolefin microporous film. The electrode body may include multiple positive electrode plates and multiple negative electrode plates, and the positive electrode tabs provided on each positive electrode plate may be laminated to form a positive electrode tab group, or the negative electrode tabs provided on each negative electrode plate may be laminated to form a negative electrode tab group. The electrode body 200 may include multiple wound electrode bodies, or may include multiple laminated electrode bodies.

[0068] (Structure of cover member 500) Fig. 13 is a perspective view showing the configuration of the cover member in this embodiment. Fig. 14 is a cross-sectional view showing the positional relationship of the cover member with respect to the electrode body and the liquid inlet. Fig. 15 is a cross-sectional view showing the configuration of the cover member in this embodiment. Note that Fig. 15 illustrates an example in which a cover member 500 is attached to a first electrode body 201 constituting an electrode body 200.

[0069] First, before describing the structure of the cover member 500, the arrangement of other components related to the cover member 500 will be described. As shown in FIG. 14, the case 100 includes a first surface. The first surface in the present embodiment is a first sealing plate 120. The first sealing plate 120 (first surface) faces the electrode body 200 in the first direction (X direction). The first sealing plate 120 (first surface) is located on the first electrode tab group 250 side.

[0070] As shown in FIGS. 3 and 14, the first sealing plate 120 (first surface) has a shape having a longitudinal direction (Z direction) and a lateral direction (Y direction) that intersect with each other when viewed from a first direction (X direction).

[0071] The first electrode tab group 250 is arranged shifted from the center of the electrode body 200 toward the end E1 on the first side in the longitudinal direction (Z direction) of the first sealing plate 120 (first surface).

[0072] The first sealing plate 120 (first surface) is provided with a liquid inlet 124. The liquid inlet 124 is provided on the second end E2 side located on the opposite side from the center of the electrode body 200 in the longitudinal direction (Z direction) to the first end E1.

[0073] Next, the structure of the cover member 500 will be described. As shown in Fig. 13 to Fig. 15, the cover member 500 covers a part of the electrode body 200. The cover member 500 in this embodiment is located on one end side of the electrode body 200 in the X direction. The cover member 500 covers a part of the electrode body 200 from the X direction and the Y direction.

[0074] The electrode body 200 in this embodiment includes a first electrode body 201 and a second electrode body 202. One cover member 500 is provided for each of the first electrode body 201 and the second electrode body 202. When a plurality of electrode bodies are arranged as in this embodiment, one cover member 500 may be configured to cover all of the plurality of electrode bodies.

[0075] The cover member 500 in this embodiment is a tape. The cover member 500, which is a tape, is attached to the electrode body 200. In this embodiment, the cover member 500 has a first portion 510 and a pair of second portions 520, which will be described later, attached to the electrode body 200.

[0076] The cover member 500 has a first portion 510 and a pair of second portions 520. The first portion 510 faces the liquid injection hole 124 in a first direction (X direction). Since the first portion 510 is aligned with the liquid injection hole 124 in the first direction (X direction), it is possible to prevent the electrolyte from directly hitting the electrode body 200 when the electrolyte is injected into the case 100 from the liquid injection hole 124.

[0077] The first portion 510 in this embodiment has a planar shape extending in the YZ plane. The first portion 510 may be U-shaped when viewed from the longitudinal direction (Z direction). In this case, the first portion 510 has a convex shape on the first sealing plate 120 side. When the first portion 510 is U-shaped, the flow of the electrolyte injected from the injection hole 124 can be tilted so that the electrolyte deviates from the electrode body.

[0078] The pair of second portions 520 sandwich the electrode body 200 in the short-side direction (Y direction) of the first sealing plate 120 (first surface).

[0079] The first electrode tab group 250 is arranged shifted in the Z direction from the center of the electrode body 200 toward the end E1 on the first side. For this reason, at the end E2 on the second side, the electrode plates of the electrode body 200 are not gathered together by a tab structure, and so on, so that the inter-electrode plate distance between the positive electrode plate 240 and the negative electrode plate 210 in the electrode body 200 may become large. By sandwiching the electrode body 200 between the pair of second parts 520 at the end E2 on the second side, it is possible to suppress an increase in the inter-electrode plate gap of the electrode body 200.

[0080] The pair of second portions 520 have approximately the same area when viewed from the Y direction. This allows the cover member 500 to apply uniform surface pressure to both sides of the electrode body 200 in the Y direction when the electrode body 200 is sandwiched between the pair of second portions 520. Note that the pair of second portions 520 may have different sizes.

[0081] In the present embodiment, the first portion 510 and the second portion 520 are continuous with each other by connecting their ends to each other. However, the first portion 510 and the second portion 520 may not be continuous by providing another configuration between the first portion 510 and the second portion 520.

[0082] The cover member 500 is not limited to a tape. The cover member 500 may be a clip. The cover member 500 may be a U-shaped structure in which the gap between the pair of second portions 520 is narrow compared to the thickness of the electrode body 200.

[0083] When the electrode body 200 is composed of a plurality of electrode bodies and each of the plurality of electrode bodies is provided with one cover member 500, the positions of the plurality of cover members 500 in the Z direction may be the same or different. When increasing the surface pressure applied from the cover member 500 to the electrode body 200 in order to suppress an increase in the inter-plate distance of the electrode body 200, it is desirable that the positions of the plurality of cover members 500 in the Z direction are the same. On the other hand, when making the surface pressure applied from the cover member 500 to the electrode body 200 uniform, it is desirable that the positions of the plurality of cover members 500 in the Z direction are different so as to avoid overlapping of the cover members 500 in the Y direction.

[0084] (Arrangement of cover member 500 relative to electrode body 200) Fig. 16 is a cross-sectional view showing the configuration of an electrode body in this embodiment. In Fig. 16, each member is shown in an exploded state in order to facilitate understanding of the configuration.

[0085] 16, the positive electrode plate 240, which is a first electrode, extends at least in a first direction (X direction). In the present embodiment, the positive electrode plate 240 is wound in a flat shape when viewed from the first direction (X direction), and therefore extends in all of the X direction, Y direction, and Z direction.

[0086] The positive electrode active material layer 242 in the positive electrode plate 240 covers at least a portion of the positive electrode core 241. The positive electrode active material layer 242 is thin at an end 244 in the first direction (X direction) of the positive electrode plate 240 due to a manufacturing method in which the positive electrode active material layer 242 is applied to the positive electrode core 241.

[0087] Fig. 17 is a cross-sectional view showing the positional relationship of the cover member with respect to the electrode body, in which each member is disassembled and shown on a different scale to facilitate understanding of the configuration.

[0088] 17, the pair of second portions 520 are located on the X-direction end side of the electrode body 200 with respect to a virtual line L extending in the Y direction. The pair of second portions 520 are not arranged side by side with the positive electrode active material layer 242 in the Y direction. As a result, the pair of second portions 520 of the cover member 500 sandwich the electrode body 200 in a range where the positive electrode active material layer 242 is not formed. As a result, the effect of a change in thickness of the positive electrode active material layer 242 on the surface pressure when the cover member 500 sandwiches the electrode body 200 can be suppressed, and therefore the surface pressure applied from the pair of second portions 520 to the electrode body 200 can be made uniform.

[0089] In the secondary battery 1 according to the embodiment of the present technology, the first part 510 of the cover member 500 faces the liquid injection hole 124 in the first direction (X direction), so that the first part 510 can protect the electrode body 200 from the injection of the electrolyte. This allows the electrolyte to be injected without decreasing the injection speed, and the electrolyte injection property can be ensured. In addition, when the first electrode tab group 250 is arranged on the end E1 side of the first side and the liquid injection hole 124 is arranged on the end E2 side of the second side in the longitudinal direction (Z direction) of the first sealing plate 120 (first surface), the inter-electrode plate distance of the electrode body 200 may be widened on the end E2 side of the second side. The pair of second parts 520 of the cover member 500 sandwich the electrode body 200 from the short-side direction (Y direction) of the first sealing plate 120 (first surface) on the end E2 side of the second side. For this reason, the pair of second portions 520 can suppress an increase in the inter-plate distance in the electrode body 200. As a result, by providing the secondary battery 1 with the cover member 500, it is possible to ensure the injection property of the electrolyte and suppress an increase in the inter-plate distance in the electrode body 200.

[0090] In the secondary battery 1 according to one embodiment of the present technology, the second portion 520 is provided in an area where the positive electrode active material layer 242 is not formed. This makes it possible to suppress the effect of a change in thickness of the positive electrode active material layer 242 on the surface pressure when the cover member 500 holds the electrode body 200, and therefore makes it possible to make uniform the surface pressure applied from the cover member 500 to the electrode body 200 when the cover member 500 holds the electrode body 200.

[0091] In the secondary battery 1 according to an embodiment of the present technology, the cover member 500 is made of tape, so that the cover member 500 can be easily configured.

[0092] In the secondary battery 1 according to one embodiment of the present technology, the tape that is the cover member 500 is attached to the electrode body 200, so that displacement of the cover member 500 with respect to the electrode body 200 can be suppressed.

[0093] Although the embodiment of the present technology has been described above, the embodiment disclosed herein should be considered as 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 scope and meaning equivalent to the claims. [Explanation of symbols]

[0094] 1 secondary battery, 100 case, 110 case body, 111 first side portion, 112 second side portion, 112A one side of the second side portion, 113 first opening, 114 second opening, 115 joint portion, 120 first sealing plate (first surface), 124 liquid injection hole, 125 gas exhaust valve, 126 sealing plate joint portion, 130 second sealing plate, 135 gas exhaust valve, 136 sealing plate joint portion, 200 electrode body, 201 first electrode body, 202 second electrode body, 210 negative electrode plate, 210S negative electrode base plate, 211 negative electrode core, 212 negative electrode active material layer, 220 second electrode tab group, 230 negative electrode tab, 240 positive electrode plate, 240S positive electrode base plate, 241 positive electrode core, 242 Positive electrode active material layer, 243 positive electrode protective layer, 244 end portion, 250 first electrode tab group, 260 positive electrode tab, 270 separator, 300 electrode terminal, 301 positive electrode terminal, 302 negative electrode terminal, 400 current collector, 400A positive electrode current collector, 400B negative electrode current collector, 500 cover member, 510 first portion, 520 second portion, A winding axis, E1 end portion on the first side, E2 end portion on the second side, L imaginary line.

Claims

1. An electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode; A case that accommodates the electrode assembly; A cover member for covering a part of the electrode body, the electrode body includes a first electrode tab group disposed at one end in a first direction and electrically connected to the first electrodes, and a second electrode tab group disposed at the other end opposite to the one end in the first direction and electrically connected to the second electrodes, the case includes a first surface facing the electrode body in the first direction and positioned on a first electrode tab group side, the first surface has a shape having a longitudinal direction and a lateral direction that intersect with each other when viewed from the first direction, the first electrode tab group is disposed offset from a center of the electrode body toward an end portion on the first side in the longitudinal direction of the first surface, a liquid injection hole is provided on the first surface on a second end side located on the opposite side from the center of the electrode body in the longitudinal direction to the end of the first side; The cover member is a first portion facing the liquid injection hole in the first direction; a pair of second portions that sandwich the electrode body in the short side direction of the first surface.

2. The first electrode is a positive electrode plate extending in at least the first direction, The positive electrode plate includes a positive electrode core and a positive electrode active material layer that covers at least a portion of the positive electrode core, The secondary battery according to claim 1 , wherein the pair of second portions sandwich the electrode body in an area where the positive electrode active material layer is not formed.

3. The secondary battery according to claim 1 , wherein the cover member is a tape.

4. The secondary battery according to claim 3 , wherein the tape is attached to the electrode body.

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