Secondary battery

Abstract

The invention provides a secondary battery. The first electrode tab group is disposed so as to be offset from the center of the electrode body toward the end of the first side in the longitudinal direction of the first surface. On the first surface, a liquid injection hole is provided on a second-side end side located on the opposite side from the first-side end side with respect to the center of the electrode body in the longitudinal direction. The cover member includes a first portion and a pair of second portions. The first portion faces the liquid injection hole in the first direction. The pair of second portions sandwich the electrode body in the short side direction of the first surface.

Description

Technical Field

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

[0002] As a prior art document disclosing a power battery, there is US Patent No. 11489221. US Patent No. 11489221 discloses a structure in which when an electrolyte is injected into a case from an injection hole, an electrode body is protected from the electrolyte injection by a blocking member. Summary of the invention

[0003] When the secondary battery includes a covering member for protecting the electrode body from electrolyte injection, there is still room for achieving both ensuring the electrolyte injection property and suppressing the increase in the distance between the electrode plates in the electrode body.

[0004] The present technology has been made to solve the above-mentioned problems, and an object of the present technology is to provide a secondary battery capable of simultaneously ensuring the injectability of an electrolyte solution and suppressing an increase in the distance between the electrode plates in an electrode assembly.

[0005] The secondary battery based on the present technology comprises an electrode body, a shell and a covering member. The electrode body comprises a first electrode and a second electrode having a polarity different from that of the first electrode. The shell accommodates the electrode body. The covering member covers a portion of the electrode body. The electrode body comprises a first electrode tab group and a second electrode tab group. The first electrode tab group is arranged at one end in the first direction and is electrically connected to the first electrode. The second electrode tab group is arranged at the other end on the opposite side of one end in the first direction and is electrically connected to the second electrode. The shell comprises a first surface. The first surface is opposite to the electrode body in the first direction and is located on the side of the first electrode tab group. The first surface has a shape including a long side direction and a short side direction intersecting each other when viewed from the first direction. The first electrode tab group is arranged offset from the center of the electrode body to the end side of the first side in the long side direction of the first surface. On the first surface, an injection hole is provided on the end side of the second side located on the opposite side of the end of the first side relative to the center of the electrode body in the long side direction. The covering member comprises a first part and a pair of second parts. The first portion faces the liquid injection hole in the first direction. The pair of second portions sandwich the electrode body in the short-side direction of the first surface.

[0006] The foregoing and other objects, features, configurations and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 This is a front view showing the structure of a secondary battery according to one embodiment of the present technology.

[0008] Figure 2It is shown when viewed from the direction of arrow II Figure 1 A diagram showing the state of a secondary battery.

[0009] Figure 3 It shows the direction of arrow III. Figure 1 A diagram showing the state of a secondary battery.

[0010] Figure 4 It is shown when viewed from the direction of arrow IV Figure 1 A diagram showing the state of a secondary battery.

[0011] Figure 5 It is shown Figure 1 A front cross-sectional view of a secondary battery is shown.

[0012] Figure 6 It is a front view showing a positive electrode original plate before forming a positive electrode plate.

[0013] Figure 7 yes Figure 6 VII-VII cross-sectional view of the positive electrode original plate shown.

[0014] Figure 8 It is a front view showing a positive electrode plate formed from a positive electrode original plate.

[0015] Fig. 9 It is a front view showing a negative electrode original plate before forming a negative electrode plate.

[0016] Fig.10 yes Fig. 9 XX cross-sectional view of the negative electrode original plate shown.

[0017] Fig.11 It is a front view showing a negative electrode plate formed from a negative electrode original plate.

[0018] Fig.12 It is a perspective view showing the structure of the electrode body according to the present embodiment.

[0019] Fig.13 It is a perspective view showing the structure of the covering member according to the present embodiment.

[0020] Fig.14 It is a cross-sectional view showing the positional relationship of the covering member with respect to the electrode body and the liquid injection hole.

[0021] Fig.15 It is a cross-sectional view showing the structure of the covering member according to the present embodiment.

[0022] Fig.16 It is a cross-sectional view showing the structure of the electrode body according to the present embodiment.

[0023] Fig.17It is a cross-sectional view showing the positional relationship of the covering member with respect to the electrode body. DETAILED DESCRIPTION

[0024] Hereinafter, embodiments of the present technology will be described. In addition, the same reference numerals may be given to the same or corresponding parts, and the description thereof may not be repeated.

[0025] In addition, in the embodiments described below, when the number, amount, etc. are mentioned, unless otherwise specified, the scope of the present technology is not necessarily limited to the number, amount, etc. In addition, in the following embodiments, each component is not an essential component for the present technology unless otherwise specified. In addition, the present technology is not limited to a configuration that necessarily exerts all the effects mentioned in the embodiments.

[0026] In addition, in this specification, the descriptions such as “comprise”, “include”, and “have” are not limiting. That is, when a certain structure is included, other structures other than the structure may be included or not.

[0027] In addition, in this specification, when geometrical terms and terms indicating position and direction relationships such as "parallel", "orthogonal", "oblique 45°", "coaxial", "along" and the like are used, these terms allow for manufacturing errors or slight variations. In this specification, when terms such as "upper side" and "lower side" are used to indicate relative positional relationships, these terms are used as terms indicating relative positional relationships in one state, and the relative positional relationships can be reversed or rotated to any angle depending on the installation direction of each mechanism (for example, turning the entire mechanism upside down, etc.).

[0028] In this specification, "secondary battery" is not limited to lithium ion battery, and may also include other secondary batteries such as nickel-hydrogen battery and sodium ion battery. In this specification, positive electrode and negative electrode are collectively referred to as "electrode".

[0029] In addition, 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 set to the X direction as the first direction, the short side direction of the shell viewed from the X direction is set to the Y direction, and the long side direction of the shell viewed from the X direction is set to the Z direction. In addition, in order to facilitate the understanding of the present technology, the dimensions of each component in the drawings are sometimes shown with some changes relative to the actual dimensions.

[0030] (Overall composition of the battery)

[0031] Figure 1 It is a front view of the secondary battery 1 according to the present embodiment. Figures 2 to 4They are respectively shown as viewed from the direction of arrow II, arrow III, and arrow IV. Figure 1 The diagram shows the state of the secondary battery 1. Figure 5 yes Figure 1 The secondary battery 1 is shown in front cross-sectional view.

[0032] The secondary battery 1 can be mounted on a battery electric vehicle (BEV), a plug-in hybrid electric vehicle (PHEV), a hybrid electric vehicle (HEV), etc. However, the use of the secondary battery 1 is not limited to vehicle-mounted use.

[0033] like Figures 1 to 5 As shown, the secondary battery 1 includes a case 100 , an electrode body 200 , an electrode terminal 300 , a current collector 400 , and a covering member 500 .

[0034] When forming a battery pack including secondary batteries 1, a plurality of secondary batteries 1 are stacked in the Y direction. The stacked secondary batteries 1 may be constrained in the stacking direction (Y direction) by a constraining member to form a battery module, or the battery pack may be directly supported on the side surface of the battery pack casing without using a constraining member.

[0035] The case 100 accommodates the electrode assembly 200 . The case 100 includes a case body 110 , a first sealing plate 120 , and a second sealing plate 130 .

[0036] The shell body 110 is composed of a cylindrical (preferably square) member. Thus, a square secondary battery 1 can be obtained. The shell body 110 is made of metal. Specifically, the shell body 110 is composed of aluminum, aluminum alloy, iron or iron alloy. When the shell body 110 is composed of iron or iron alloy, the shell body 110 can also be plated with nickel, tin or zinc.

[0037] like Figure 1 as well as Figure 2 As shown in FIG. 1 , a first sealing plate 120 and a second sealing plate 130 are provided at both ends of the housing body. The housing body 110 can be formed by, for example, bringing the ends of the plate-like members that have been bent into contact with each other ( Figure 2 The illustrated joint portion 115) is joined to each other (eg, laser welded) to form a square tube shape. The corners of the "square tube shape" may also have a rounded corner (R angle) shape.

[0038] In the present embodiment, the shell body 110 is formed longer in the X direction of the secondary battery 1 than in the Y direction and the Z direction of the secondary battery 1. The dimension of the shell body 110 in the X direction is preferably about 30 cm or more. Thus, a relatively large (high capacity) secondary battery 1 can be formed. The dimension of the shell body 110 in the Z direction is preferably about 20 cm or less, more preferably about 15 cm or less, and further preferably about 10 cm or less. Thus, a secondary battery 1 with a relatively low height (low height) can be formed, for example, the mountability on a vehicle is improved.

[0039] The housing body 110 includes a pair of first side surfaces 111 and a pair of second side surfaces 112 . The pair of first side surfaces 111 face each other in the Y direction. The pair of first side surfaces 111 constitute a part of the side surfaces of the housing 100 .

[0040] The pair of second side surfaces 112 face each other in the Z direction. The pair of second side surfaces 112 constitute the bottom surface portion and the top surface portion of the housing 100 .

[0041] The pair of first side portions 111 and the pair of second side portions 112 are respectively arranged in a mutually intersecting manner. The pair of first side portions 111 and the pair of second side portions 112 are connected at each end. As in the present embodiment, it is preferred that the area of ​​each of the pair of second side portions 112 is smaller than the area of ​​each of the pair of first side portions 111.

[0042] like Figure 2 As shown, a joint portion 115 is formed on one of the pair of second side portions 112A. The joint portion 115 extends from the first opening 113 to the second opening 114. That is, the joint portion 115 extends in the X direction of the secondary battery 1. At the joint portion 115, the end sides of the plate-like members constituting the case body 110 are joined to each other.

[0043] like Figure 3 As shown, a first opening 113 is provided at one end of the housing body 110 in the first direction (X direction). The first opening 113 is sealed by a first sealing plate 120. A sealing plate joint 126 is formed in the first opening 113 to seal the first opening 113. The first opening 113 and the 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.

[0044] The first sealing plate 120 is provided with a positive electrode terminal 301 (first electrode terminal), a liquid injection hole 124, and a gas discharge valve 125. The positions of the positive electrode terminal 301, the liquid injection hole 124, and the gas discharge valve 125 can be changed as appropriate.

[0045] like Figure 4As shown in FIG. 1 , a second opening 114 is provided at the other end of the housing body 110 in the first direction (X direction). That is, the second opening 114 is located at the end opposite to the first opening 113. The second opening 114 is sealed by the second sealing plate 130. A sealing plate joint 136 is formed at the second opening 114 to seal the second opening 114. The second opening 114 and the 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.

[0046] The second sealing plate 130 is provided with a negative electrode terminal 302 (second electrode terminal) and a gas exhaust valve 135. The positions of the negative electrode terminal 302 and the gas exhaust valve 135 can be changed as appropriate.

[0047] The first sealing plate 120 and the second sealing plate 130 are made of metal. Specifically, the first sealing plate 120 and the second sealing plate 130 are made of aluminum, aluminum alloy, iron or iron alloy. When the first sealing plate 120 and the second sealing plate 130 are made of iron or iron alloy, the first sealing plate 120 and the second sealing plate 130 may be plated with nickel, tin or zinc.

[0048] 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 .

[0049] 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 .

[0050] The positive electrode terminal 301 is made of a conductive material (more specifically, a metal), for example, aluminum or an aluminum alloy.

[0051] The negative electrode terminal 302 is made of a conductive material (more specifically, a metal), for example, copper or a copper alloy, etc. A portion or layer made of aluminum or an aluminum alloy may be provided on the outer surface of the negative electrode terminal 302 .

[0052] The liquid injection hole 124 is sealed by a sealing member (not shown). As the sealing member, for example, a blind rivet or other metal member can be used.

[0053] The electrode body 200 is a flat electrode body having a positive electrode plate and a negative electrode plate described below. Specifically, the electrode body 200 is a wound electrode body in which a strip-shaped positive electrode plate and a strip-shaped negative electrode plate are wound together via a strip-shaped separator.

[0054] like Figure 5 As shown, the case 100 accommodates the electrode body 200. The electrode body 200 is accommodated in the case 100 so that the winding axis thereof is parallel to the X direction.

[0055] Specifically, a single or multiple wound electrode bodies are housed together with an electrolyte (electrolyte) (not shown) on the inner side of an insulating sheet (not shown) disposed in the housing 100. As the electrolyte (non-aqueous electrolyte), for example, the following electrolyte can be used: LiPF6 is dissolved at a concentration of 1.2 mol / L in a non-aqueous solvent obtained by mixing ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) in a volume ratio (25° C.) of 30:30:40. In addition, a solid electrolyte may be used instead of an electrolyte.

[0056] The electrode body 200 includes a main body (a portion where the positive electrode plate and the negative electrode plate are stacked with a separator interposed therebetween), a first electrode tab group 250 (positive electrode tab group), and a second electrode tab group 220 (negative electrode tab group).

[0057] The main body portion is composed of a positive electrode plate 240 (first electrode) and a negative electrode plate 210 (second electrode) to be described later.

[0058] The first electrode tab group 250 is disposed at one end of the electrode body 200 in the first direction (X direction). Specifically, the first electrode tab group 250 is disposed at an end of the main body on the first sealing plate 120 side in the X direction.

[0059] The second electrode tab group 220 is disposed at the other end of the electrode body 200 opposite to the one end in the first direction (X direction). Specifically, the second electrode tab group 220 is disposed at the end of the body portion on the second sealing plate 130 side in the X direction.

[0060] 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 toward the first sealing plate 120 or the second sealing plate 130 , respectively.

[0061] The first electrode tab group 250 is electrically connected to the first electrode. The second electrode tab group 220 is electrically connected to the second electrode.

[0062] 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 formed of a plate-like member. The electrode body 200 is electrically connected to the positive electrode terminal 301 and the negative electrode terminal 302 via the current collector 400 .

[0063] The positive electrode collector 400A is arranged on the first sealing plate 120 via an insulating member made of resin. The positive electrode collector 400A is electrically connected to the first electrode tab group 250 and the positive terminal 301. The positive electrode collector 400A is made of a conductive material (more specifically, a metal), for example, aluminum or an aluminum alloy. In addition, the first electrode tab group 250 can be electrically connected to the first sealing plate 120 directly or via the positive electrode collector 400A. In this case, the first sealing plate 120 also plays the role of the positive terminal 301.

[0064] 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, metal), such as copper or a copper alloy.

[0065] The covering member 500 covers a portion of the electrode body 200. The structure of the covering member 500 will be described later.

[0066] (Configuration of Electrode Body 200)

[0067] Figure 6 1 is a front view showing the positive electrode original plate 240S before the positive electrode plate 240 is formed. Figure 7 yes Figure 6 The positive electrode original plate 240S is shown in cross-sectional view taken along line VII-VII. Figure 8 1 is a front view showing a positive electrode plate 240 formed from a positive electrode original plate 240S.

[0068] The positive electrode plate 240 as the first electrode is manufactured by processing a positive electrode original plate 240S. Figure 6 as well as Figure 7 As shown, the positive electrode original plate 240S includes a positive electrode core 241, a positive electrode active material layer 242, and a positive electrode protective layer 243. The positive electrode core 241 is an aluminum foil or an aluminum alloy foil.

[0069] The positive electrode core body 241 has a positive electrode active material layer 242 formed thereon except for the end portion on one side of both surfaces. The positive electrode active material layer 242 is formed on the positive electrode core body 241 by applying a positive electrode active material layer slurry using a die coater.

[0070] The positive electrode active material layer slurry is prepared by mixing lithium nickel cobalt manganese composite oxide as a 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 dispersant in a mass ratio of lithium nickel cobalt manganese composite oxide:PVdF:carbon material of approximately 97.5:1:1.5.

[0071] The positive electrode protection layer 243 is in contact with the positive electrode core 241 and is formed at one end of the positive electrode active material layer 242 in the width direction. The positive electrode protection layer 243 is formed on the positive electrode core 241 by applying the positive electrode protection layer slurry by a die coater. The positive electrode protection layer 243 has a resistance greater than that of the positive electrode active material layer 242.

[0072] The positive electrode protective layer slurry was prepared by kneading alumina powder, a carbon material as a conductive material, PVdF as a binder, and NMP as a dispersant so that the mass ratio of alumina powder:carbon material:PVdF was about 83:3:14.

[0073] By drying the positive electrode core 241 coated with the positive electrode active material layer slurry and the positive electrode protective layer slurry, the NMP contained in the positive electrode active material layer slurry and the positive electrode protective layer slurry is removed, thereby forming the positive electrode active material layer 242 and the positive electrode protective layer 243. Furthermore, by compressing the positive electrode active material layer 242, the positive electrode original plate 240S including the positive electrode core 241, the positive electrode active material layer 242 and the positive electrode protective layer 243 is formed. The positive electrode original plate 240S is cut into a predetermined shape to form the positive electrode plate 240. The positive electrode original plate 240S can be cut by laser processing, die processing, or cutting processing based on energy line irradiation.

[0074] like Figure 8 As shown, at one end in the width direction of the positive electrode plate 240 formed from the positive electrode original plate 240S, a plurality of positive electrode tabs 260 formed by the positive electrode core 241 are provided. When the positive electrode plate 240 is wound, the plurality of positive electrode tabs 260 are stacked to form a first electrode tab group 250. Thus, the first electrode tab group 250 is connected to the positive electrode plate 240 (first electrode). Considering the state in which the first electrode tab group 250 is connected to the positive electrode collector 400A, the positions of the plurality of positive electrode tabs 260 and the lengths in the protruding direction can be appropriately adjusted. In addition, the shape of the positive electrode tab 260 is not limited to. Figure 8 The illustrated shape.

[0075] The positive electrode protection layer 243 is provided at the root of each of the plurality of positive electrode tabs 260. The positive electrode protection layer 243 does not necessarily need to be provided at the root of the positive electrode tab 260.

[0076] Fig. 9 1 is a front view showing a negative electrode original plate before the negative electrode plate 210 is formed. Fig.10 yes Fig. 9 A cross-sectional view taken along the line XX of the negative electrode original plate 210S is shown. Fig.11 1 is a front view showing a negative electrode plate 210 formed from a negative electrode original plate 210S.

[0077] The negative electrode plate 210 as the second electrode has a different polarity from the positive electrode plate 240 as the first electrode. The negative electrode plate 210 is manufactured by processing a negative electrode original plate 210S. Fig. 9 as well as Fig.10 As shown, the negative electrode original plate 210S includes a negative electrode core 211 and a negative electrode active material layer 212. The negative electrode core 211 is a copper foil or a copper alloy foil.

[0078] A negative electrode active material layer 212 is formed on the negative electrode core 211 except for the end portion on one side of both surfaces. The negative electrode active material layer 212 is formed by applying a negative electrode active material layer slurry using a die coater.

[0079] The negative electrode active material layer slurry was prepared by kneading graphite as the negative electrode active material, styrene butadiene rubber (SBR) and carboxymethyl cellulose (CMC) as binders, and water as a dispersant so that the mass ratio of graphite:SBR:CMC was about 98:1:1.

[0080] 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 original plate 210S including the negative electrode core 211 and the negative electrode active material layer 212 is formed by compressing the negative electrode active material layer 212. The negative electrode original plate 210S is cut into a predetermined shape to form the negative electrode plate 210. The negative electrode original plate 210S can be cut by laser processing, die processing, or cutting processing based on energy line irradiation.

[0081] like Fig.11 As shown, at one end in the width direction of the negative electrode plate 210 formed from the negative electrode original plate 210S, a plurality of negative electrode tabs 230 formed by the negative electrode core 211 are provided. 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). Considering the state in which the second electrode tab group 220 is connected to the negative electrode collector 400B, the positions of the plurality of negative electrode tabs 230 and the lengths in the protruding direction can be appropriately adjusted. In addition, the shape of the negative electrode tab 230 is not limited to. Fig.11 The illustrated shape.

[0082] In a typical example, the thickness of the negative electrode tab 230 (one) is smaller than the thickness of the positive electrode tab 260 (one). In this case, the thickness of the second electrode tab group 220 is smaller than the thickness of the first electrode tab group 250.

[0083] Fig.12 It is a perspective view showing the structure of the electrode body according to the present embodiment.

[0084] like Fig.12 As shown, the electrode body 200 of the present embodiment is wound with the separator 270 sandwiched between each of 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 the winding axis A extending in the X direction. However, in this specification, the "electrode body" is not limited to a wound electrode body, but may also be a stacked electrode body in which a plurality of positive plates and a plurality of negative plates are alternately stacked. The strip-shaped separator 270 can be composed of a polyolefin microporous film, for example. The electrode body includes a plurality of positive plates and a plurality of negative plates, and the positive electrode tabs provided on each positive plate can be stacked to form a positive electrode tab group, and the negative electrode tabs provided on each negative plate can be stacked to form a negative electrode tab group. In addition, the electrode body 200 may include a plurality of wound electrode bodies, or may include a plurality of stacked electrode bodies.

[0085] (Structure of Covering Member 500)

[0086] Fig.13 It is a perspective view showing the structure of the covering member according to the present embodiment. Fig.14 It is a cross-sectional view showing the positional relationship of the covering member with respect to the electrode body and the liquid injection hole. Fig.15 is a cross-sectional view showing the structure of the covering member of this embodiment. Fig.15 2 , a case where the covering member 500 is attached to the first electrode body 201 constituting the electrode body 200 is exemplified.

[0087] First, before describing the structure of the cover member 500, the configuration of other components associated with the cover member 500 will be described. Fig.14 As shown, the housing 100 includes a first surface. The first surface of 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.

[0088] like Figure 3 as well as Fig.14 As shown, the first sealing plate 120 (first surface) has a shape including a long side direction (Z direction) and a short side direction (Y direction) intersecting each other when viewed from the first direction (X direction).

[0089] The first electrode tab group 250 is disposed offset from the center of the electrode body 200 toward the first end E1 side in the longitudinal direction (Z direction) of the first sealing plate 120 (first surface).

[0090] The first sealing plate 120 (first surface) is provided with a liquid injection hole 124. The liquid injection hole 124 is provided on the second end E2 side located opposite to the first end E1 with respect to the center of the electrode body 200 in the longitudinal direction (Z direction).

[0091] Next, the structure of the covering member 500 will be described. Figure 13~Figure 15 As shown, the covering member 500 covers a part of the electrode body 200. The covering member 500 of this embodiment is located on one end side of the electrode body 200 in the X direction. The covering member 500 covers a part of the electrode body 200 from the X direction and the Y direction.

[0092] The electrode body 200 of the present embodiment includes a first electrode body 201 and a second electrode body 202. One covering member 500 is provided on each of the first electrode body 201 and the second electrode body 202. In addition, when a plurality of electrode bodies are arranged as in the present embodiment, a single covering member 500 may cover all of the plurality of electrode bodies.

[0093] The covering member 500 of the present embodiment is a tape material. The covering member 500 as a tape material is attached to the electrode body 200. The first portion 510 and a pair of second portions 520 described later of the covering member 500 of the present embodiment are attached to the electrode body 200.

[0094] The covering member 500 includes a first portion 510 and a pair of second portions 520. The first portion 510 faces the injection hole 124 in the first direction (X direction). By arranging the first portion 510 and the injection hole 124 in the first direction (X direction), when the electrolyte is injected into the interior of the housing 100 from the injection hole 124, it is possible to prevent the electrolyte from directly contacting the electrode body 200.

[0095] The first portion 510 of the present embodiment has a planar shape extending in the YZ plane. In addition, the first portion 510 may be U-shaped when viewed from the long side 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 can be tilted in such a way that the electrolyte injected from the injection hole 124 is separated from the electrode body.

[0096] The pair of second portions 520 sandwich the electrode assembly 200 in the short-side direction (Y direction) of the first sealing plate 120 (first surface).

[0097] The first electrode tab group 250 is arranged offset from the center of the electrode body 200 toward the end E1 side of the first side in the Z direction. Therefore, on the end E2 side of the second side, the distance between the positive electrode plate 240 and the negative electrode plate 210 in the electrode body 200 may become larger because the electrode plates of the electrode body 200 are not brought together by the tab structure. By clamping the electrode body 200 by a pair of second portions 520 on the end E2 side of the second side, the increase in the gap between the electrode plates of the electrode body 200 can be suppressed.

[0098] The pair of second portions 520 have substantially the same area when viewed from the Y direction. Thus, when the electrode body 200 is sandwiched by the pair of second portions 520, surface pressure can be uniformly applied from the covering member 500 to both sides of the electrode body 200 in the Y direction. In addition, the size of each of the pair of second portions 520 may be different from each other.

[0099] The first portion 510 and the second portion 520 of this embodiment are connected at their ends to be continuous. Alternatively, the first portion 510 and the second portion 520 may be discontinuous by interposing another structure therebetween.

[0100] The covering member 500 is not limited to a tape, but may be a clip. The covering member 500 may be a U-shaped structure in which the gap between the pair of second portions 520 is small relative to the thickness of the electrode body 200 .

[0101] When the electrode body 200 is composed of a plurality of electrode bodies and one covering member 500 is provided on each of the plurality of electrode bodies, the positions of the plurality of covering members 500 in the Z direction may be the same or different. In order to suppress the increase in the distance between the electrode plates of the electrode body 200 and increase the surface pressure applied from the covering member 500 to the electrode body 200, it is preferred that the positions of the plurality of covering members 500 in the Z direction are the same. On the other hand, in order to make the surface pressure applied from the covering member 500 to the electrode body 200 uniform, it is preferred that the positions of the plurality of covering members 500 in the Z direction are different so as to avoid overlapping of the covering members 500 in the Y direction.

[0102] (Arrangement of Covering Member 500 with Respect to Electrode Body 200)

[0103] Fig.16 2 is a cross-sectional view showing the structure of the electrode body of this embodiment. Fig.16 In order to facilitate understanding of the structure, each component is shown in an exploded state.

[0104] like Fig.16As shown, the positive electrode plate 240 as the first electrode extends at least in the first direction (X direction). In this embodiment, the positive electrode plate 240 is wound into a flat shape when viewed from the first direction (X direction), and thus extends in any direction of the X direction, the Y direction, and the Z direction.

[0105] 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 thinner at an end 244 of the positive electrode plate 240 in the first direction (X direction) by a manufacturing method based on coating on the positive electrode core 241.

[0106] Fig.17 is a cross-sectional view showing the positional relationship of the covering member with respect to the electrode body. Fig.17 In order to facilitate understanding of the structure, each component is decomposed and shown in a state with a changed proportion.

[0107] like Fig.17 As shown in FIG. 1 , the pair of second portions 520 are located on the end side of the electrode body 200 in the X direction relative to the imaginary line L extending in the Y direction. The pair of second portions 520 are not arranged in line with the positive electrode active material layer 242 in the Y direction. Thus, the pair of second portions 520 of the covering 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 influence caused by the thickness variation of the positive electrode active material layer 242 can be suppressed with respect to the surface pressure of the electrode body 200 sandwiched by the covering member 500, and thus, the surface pressure applied to the electrode body 200 from the pair of second portions 520 can be made uniform.

[0108] In the secondary battery 1 according to one embodiment of the present technology, the first portion 510 of the covering member 500 faces the injection hole 124 in the first direction (X direction), so that the first portion 510 can protect the electrode body 200 from the influence of the electrolyte injection. As a result, the electrolyte injection can be performed without reducing the injection speed, and the electrolyte injection property can be ensured. In addition, in the long side direction (Z direction) of the first sealing plate 120 (first surface), the first electrode tab group 250 is arranged on the end E1 side of the first side, and the injection hole 124 is arranged on the end E2 side of the second side. In this case, the distance between the pole plates of the electrode body 200 on the end E2 side of the second side is sometimes increased. A pair of second portions 520 of the covering member 500 clamps 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. Therefore, the pair of second portions 520 can suppress the increase in the distance between the electrodes in the electrode assembly 200. As a result, the secondary battery 1 includes the cover member 500, which can simultaneously ensure the injectability of the electrolyte and suppress the increase in the distance between the electrodes in the electrode assembly 200.

[0109] In the secondary battery 1 according to one embodiment of the present technology, the second portion 520 is provided in a range where the positive electrode active material layer 242 is not formed. Thus, the influence of the thickness variation of the positive electrode active material layer 242 on the surface pressure of the electrode body 200 sandwiched by the covering member 500 can be suppressed, and thus, when the covering member 500 sandwiches the electrode body 200, the surface pressure applied from the covering member 500 to the electrode body 200 can be made uniform.

[0110] In the secondary battery 1 according to one embodiment of the present technology, since the covering member 500 is a tape material, the covering member 500 can be configured in a simple manner.

[0111] In the secondary battery 1 according to one embodiment of the present technology, since the tape material as the covering member 500 is attached to the electrode body 200 , positional deviation of the covering member 500 relative to the electrode body 200 can be suppressed.

[0112] Although the embodiments of the present invention have been described, the embodiments disclosed this time should be considered to be illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the claims, and it is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A secondary battery, wherein: The secondary battery has: an electrode body comprising a first electrode and a second electrode having a polarity different from that of the first electrode; A shell, the shell accommodating the electrode body; as well as a covering member covering a portion of the electrode body, The electrode body includes: a first electrode tab group, which is arranged at one end in the first direction and electrically connected to the first electrode; and a second electrode tab group, which is arranged at the other end on the opposite side of the one end in the first direction and electrically connected to the second electrode. The housing includes a first surface, the first surface facing the electrode body in the first direction and located on the first electrode tab group side. The first surface has a shape including a long side direction and a short side direction intersecting each other when viewed from the first direction. The first electrode tab group is arranged offset from the center of the electrode body toward the end of the first side in the longitudinal direction of the first surface. The first surface is provided with a liquid injection hole at a second end portion located on the opposite side to the first end portion relative to the center of the electrode body in the longitudinal direction. The above-mentioned covering member comprises: a first portion, the first portion facing the liquid injection hole in the first direction; and A pair of second portions sandwiching the electrode body in the short-side direction of the first surface.

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

3. The secondary battery according to claim 1 or 2, wherein: The above-mentioned covering member is a strip material.

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

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