Battery monomer

Abstract

The invention belongs to the technical field of batteries, and discloses a battery monomer which comprises a shell, a cover plate assembly and a pole group, the length direction of the shell is a first direction, one of the width direction and the thickness direction of the shell is a second direction, the cover plate assembly covers an opening of the shell, the pole group comprises a first pole group body and two second pole group bodies, and the first pole group body and the two second pole group bodies are arranged in parallel. The two second pole assembly bodies are located on the two sides of the first pole assembly body in the first direction respectively and are both connected with the first pole assembly body in a spliced mode, and the size of the first pole assembly body in the second direction is larger than that of the second pole assembly bodies in the second direction, so that the structural strength of the pole assembly can be improved on the basis that the length size of the pole assembly is increased, and the service life of the pole assembly is prolonged. Particularly, the structural strength of the middle position of the pole group in the length direction is improved, and meanwhile the production difficulty of the pole group is reduced.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more particularly to a single battery cell. Background Technology

[0002] In existing technologies, to increase the capacity of the electrode assembly, the length of the electrode assembly is usually extended, that is, the size of the electrode assembly is increased in the length direction of the battery cell.

[0003] Because of its longer electrode assembly, this structure reduces the electrode assembly's structural strength, making it prone to bending and deformation during manufacturing. Furthermore, the increased length of the electrode assembly raises the manufacturing difficulty, thereby reducing its yield and production efficiency.

[0004] Therefore, there is an urgent need to propose a new type of battery cell to solve the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide a battery cell that can improve the structural strength of the electrode assembly, especially the structural strength of the middle part of the electrode assembly along the length direction, while reducing the manufacturing difficulty of the electrode assembly, based on increasing the length dimension of the electrode assembly.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] A single battery cell, comprising:

[0008] The shell has its length direction as the first direction and one of the width direction and thickness direction as the second direction.

[0009] A cover assembly that covers the opening in the housing;

[0010] The pole assembly includes a first pole assembly body and two second pole assemblies. The two second pole assemblies are located on both sides of the first pole assembly body in a first direction, and both second pole assemblies are spliced ​​and connected to the first pole assembly body. The size of the first pole assembly body in the second direction is larger than the size of the second pole assembly body in the second direction.

[0011] Optionally, the second electrode assembly includes an electrode body and a first protrusion. The first protrusion protrudes from the side wall of the electrode body in the second direction. The wall of the housing in the second direction is a limiting wall. The limiting wall has two first limiting grooves on the side facing the electrode assembly. The two first limiting grooves correspond one-to-one with the first protrusions of the two second electrode assemblies. Each first protrusion is insulated and embedded in a corresponding first limiting groove.

[0012] Optionally, the second electrode assembly further includes a capacity-enhancing structure, which protrudes from one end of the electrode assembly body away from the first electrode assembly; the number of openings and cover plate assemblies are two and correspond one-to-one, with the two cover plate assemblies located on both sides of the housing in the first direction; the cover plate assembly has a limiting groove structure on the side facing the housing, and the two cover plate assemblies correspond one-to-one with the two second electrode assemblies, with the capacity-enhancing structure of each second electrode assembly being insulated and embedded in the limiting groove structure of the corresponding cover plate assembly.

[0013] Optionally, the other of the width direction and the thickness direction of the housing is a third direction; the capacity-enhancing structure includes a second protrusion and two third protrusions, the two third protrusions being located on both sides of the second protrusion in the third direction, the second protrusion having an electrode tab on the side away from the electrode assembly body, and on the same second electrode assembly body, along the direction away from the first electrode assembly body, the third protrusion protrudes from the electrode tab, and the third protrusion protrudes from the electrode tab on both sides in the second direction.

[0014] Optionally, the second protrusion is provided with a first plane and two first slopes. The first plane is located on the side of the second protrusion away from the electrode assembly body. The two first slopes are respectively connected to the two sides of the first plane in the second direction, and the two first slopes are inclined in a direction that approaches each other along the direction of the first plane away from the electrode assembly body.

[0015] The third protrusion has a second plane and two second slopes. The second plane is located on the side of the third protrusion away from the electrode assembly body. The two second slopes are respectively connected to the two sides of the second plane in the second direction, and along the direction of the second plane away from the electrode assembly body, the two second slopes are inclined in a direction that is close to each other.

[0016] Optionally, the electrode includes a first electrode body and two second electrode bodies. The first electrode body is located on a first plane and extends along a second direction to both sides of the first plane. The two second electrode bodies correspond one-to-one with two first slopes. Each second electrode body is located on a corresponding first slope and extends along the inclination direction of the corresponding first slope. One end of the second electrode body is connected to the first electrode body, and the other end extends to the side of the first slope away from the first plane.

[0017] And / or, a second conductive plate is provided in the limiting groove structure, the second conductive plate is connected to the electrode tab, and multiple electrode tabs are provided on the same second protrusion.

[0018] Optionally, the dimension of the second plane in the second direction is W1, and the distance between the two second slopes on opposite sides in the second direction on the same third protrusion is W2, where 0.41≤W1 / W2≤0.79.

[0019] Optionally, the dimension of the pole assembly in the third direction is B, and the dimension of the second protrusion in the third direction is L1, where 0.36≤L1 / B≤0.64.

[0020] Optionally, on the same second pole assembly, there are two first protrusions, and the two first protrusions are arranged opposite to each other along the second direction; there are two limiting walls, and the two limiting walls are arranged opposite to each other along the second direction.

[0021] And / or, the first protrusion extends from one end of the pole body to the other end along a first direction.

[0022] Optionally, the dimension of the pole group in the first direction is E, and the dimension of the first pole group body in the first direction is F, where 0.29 ≤ F / E ≤ 0.59.

[0023] The beneficial effects of this invention are:

[0024] The two second pole groups are located on both sides of the first pole group in the first direction, and are both connected to the first pole group. Compared with extending a single pole group, this pole group is formed by combining the first pole group and the two second pole groups. This allows for an increase in the length of the pole group while reducing the length of the first and second pole groups, thereby improving the structural strength of the first and second pole groups. This is beneficial for improving the overall structural strength of the pole group and reducing the probability of bending deformation problems in the pole group.

[0025] Secondly, while increasing the length of the electrode assembly, this structure reduces the length of the first and second electrode assemblies, thereby reducing the production difficulty of the first and second electrode assemblies. Furthermore, in actual production, the first and second electrode assemblies can be produced separately and then assembled together. It is evident that this structure can reduce the overall production difficulty of the electrode assembly, which is beneficial to improving the production yield and efficiency of the electrode assembly.

[0026] Secondly, the risk of bending deformation is relatively high at the midpoint along the length of the electrode assembly, especially when the electrode assembly is long. In this battery cell, the first electrode assembly body is located at the midpoint along the length of the electrode assembly, and the dimension of the first electrode assembly body in the second direction is larger than that of the second electrode assembly body in the second direction. This structure achieves the effect of widening or thickening at the midpoint along the length of the electrode assembly, thereby improving the structural strength at the midpoint and reducing the probability of bending deformation at the midpoint. In addition, widening or thickening at the midpoint of the electrode assembly increases the volume of the electrode assembly, thereby increasing the capacity of the electrode assembly and meeting the high-rate fast charging requirements of the battery cell. Attached Figure Description

[0027] Figure 1This is a schematic diagram of the structure of a battery cell provided by the present invention;

[0028] Figure 2 This is a schematic diagram of the structure of the housing provided by the present invention;

[0029] Figure 3 This is a schematic diagram of the first structure of the pole assembly provided by the present invention;

[0030] Figure 4 This is a schematic diagram of the structure of the first pole assembly provided by the present invention;

[0031] Figure 5 This is a schematic diagram of the first structure of the second pole assembly provided by the present invention;

[0032] Figure 6 This is a first structural schematic diagram of the cover plate assembly provided by the present invention;

[0033] Figure 7 This is an exploded structural diagram of the cover plate assembly provided by the present invention;

[0034] Figure 8 This is a schematic diagram of the second structure of the cover plate assembly provided by the present invention;

[0035] Figure 9 This is a schematic diagram of the second structure of the second pole assembly provided by the present invention;

[0036] Figure 10 This is a schematic diagram of the second structure of the pole group provided by the present invention;

[0037] Figure 11 yes Figure 10 MM direction sectional view.

[0038] In the picture:

[0039] D1, First direction; D2, Second direction; D3, Third direction; 100, Housing; 110, Opening; 120, Limiting wall; 121, First limiting groove; 122, Raised portion; 200, Cover plate assembly; 210, Limiting groove structure; 211, Second limiting groove; 212, Third limiting groove; 220, Second conductive plate; 230, First insulating component; 240, First conductive plate; 250, Second insulating component; 260, Conductive post; 270, Cover plate; 271, First cover body; 272, Second cover body; 310, First pole assembly; 311, First connecting portion; 31 11. Slot; 312. First conductive layer; 313. Second conductive layer; 320. Second electrode assembly; 321. Electrode assembly body; 322. First protrusion; 323. Capacitance enhancement structure; 3231. Second protrusion; 3231a. First plane; 3231b. First slope; 3232. Third protrusion; 3232a. Second plane; 3232b. Second slope; 324. Second connecting part; 3241. Fourth protrusion; 325. Third conductive layer; 326. Fourth conductive layer; 330. Electrode tab; 331. First electrode tab body; 332. Second electrode tab body. Detailed Implementation

[0040] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0041] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0042] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0043] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0044] This embodiment provides a battery cell that can improve the structural strength of the electrode assembly by increasing the length of the electrode assembly, especially the structural strength of the middle part of the electrode assembly in the length direction, while reducing the production difficulty of the electrode assembly.

[0045] Specifically, such as Figures 1 to 3 As shown, the battery cell includes a housing 100, a cover assembly 200, and an electrode assembly. The length direction of the housing 100 is a first direction D1, and one of the width direction or the thickness direction of the housing 100 is a second direction D2. The cover assembly 200 covers the opening 110 of the housing 100. The electrode assembly includes a first electrode assembly body 310 and two second electrode assembly bodies 320. The two second electrode assembly bodies 320 are located on both sides of the first electrode assembly body 310 in the first direction D1, and both second electrode assembly bodies 320 are spliced ​​and connected to the first electrode assembly body 310. The size of the first electrode assembly body 310 in the second direction D2 is larger than the size of the second electrode assembly body 320 in the second direction D2.

[0046] In this embodiment, the thickness direction of the housing 100 is the second direction D2, and the width direction of the housing 100 is the third direction D3. Of course, in other embodiments, the thickness direction of the housing 100 may be the third direction D3, and the width direction of the housing 100 may be the second direction D2.

[0047] Based on the above design, the two second pole groups 320 are located on both sides of the first pole group 310 in the first direction D1, and are both connected to the first pole group 310. Compared with extending a single pole group, this pole group is formed by assembling the first pole group 310 and the two second pole groups 320. This allows for a reduction in the length of the first pole group 310 and the second pole group 320 while increasing the overall length of the pole group. This improves the structural strength of the first pole group 310 and the second pole group 320, which is beneficial for improving the overall structural strength of the pole group and reducing the probability of bending deformation.

[0048] Secondly, while increasing the length of the electrode assembly, this structure reduces the length of the first electrode assembly 310 and the second electrode assembly 320, thereby reducing the manufacturing difficulty of the first electrode assembly 310 and the second electrode assembly 320. In actual production, the first electrode assembly 310 and the second electrode assembly 320 can be manufactured separately and then assembled. It is evident that this structure can reduce the overall manufacturing difficulty of the electrode assembly and is conducive to improving the production yield and efficiency of the electrode assembly.

[0049] Secondly, the risk of bending deformation is relatively high at the midpoint along the length of the electrode assembly, especially when the electrode assembly is long. In this battery cell, the first electrode assembly body 310 is located at the midpoint along the length of the electrode assembly, and the dimension of the first electrode assembly body 310 in the second direction D2 is larger than the dimension of the second electrode assembly body 320 in the second direction D2. This structure achieves the effect of widening or thickening at the midpoint along the length of the electrode assembly, thereby improving the structural strength at the midpoint and reducing the probability of bending deformation at the midpoint. In addition, widening or thickening at the midpoint of the electrode assembly increases the volume of the electrode assembly, thereby increasing the capacity of the electrode assembly and meeting the high-rate fast charging requirements of the battery cell.

[0050] Optionally, such as Figures 1 to 5 As shown, the first electrode assembly 310 has a first connecting portion 311, and the second electrode assembly 320 has a second connecting portion 324. One of the first connecting portion 311 and the second connecting portion 324 is a fourth protrusion 3241, and the other is a slot 3111. The fourth protrusion 3241 is inserted into the slot 3111. When assembling the first electrode assembly 310 and the second electrode assembly 320, the fourth protrusion 3241 is simply inserted into the slot 3111. This connection structure is simple and can not only achieve rapid positioning of the first electrode assembly 310 and the second electrode assembly 320, but also help reduce the assembly difficulty of the first electrode assembly 310 and the second electrode assembly 320, thereby improving the assembly yield and assembly efficiency of the first electrode assembly 310 and the second electrode assembly 320. In addition, after the first pole assembly 310 and the second pole assembly 320 are assembled, the inner wall of the slot 3111 limits the fourth protrusion 3241, reducing the probability of relative displacement between the first pole assembly 310 and the second pole assembly 320, which is beneficial to improving the stability of the pole assembly structure.

[0051] Furthermore, the first connecting portion 311 extends from one side of the first pole assembly 310 to the other side along the second direction D2, and the second connecting portion 324 extends from one side of the second pole assembly 320 to the other side along the second direction D2. The slot 3111 is a through slot. This structure can increase the connection area between the slot 3111 and the fourth protrusion 3241, thereby improving the stability of the connection between the first pole assembly 310 and the second pole assembly 320. In addition, when assembling the first pole assembly 310 and the second pole assembly 320, the slot 3111 can guide the fourth protrusion 3241, which is beneficial to improving the assembly accuracy of the first pole assembly 310 and the second pole assembly 320.

[0052] In this embodiment, the first connecting portion 311 is a slot 3111, that is, the slot 3111 extends from one side of the first pole assembly 310 to the other side along the second direction D2. The second connecting portion 324 is a fourth protrusion 3241, that is, the fourth protrusion 3241 extends from one side of the second pole assembly 320 to the other side along the second direction D2. Of course, in other embodiments, the first connecting portion 311 may be the fourth protrusion 3241, and the second connecting portion 324 may be the slot 3111.

[0053] Optionally, the first electrode assembly 310 has a first conductive layer 312 and a second conductive layer 313 on the side facing the second electrode assembly 320. The first conductive layer 312 and the second conductive layer 313 have opposite polarities and are spaced apart. In this embodiment, the first conductive layer 312 and the second conductive layer 313 are located on opposite sides of the first connecting portion 311 in the third direction D3. The second electrode assembly 320 has a third conductive layer 325 and a fourth conductive layer 326 on the side facing the first electrode assembly 310. The third conductive layer 325 has the same polarity as the first conductive layer 312, and the fourth conductive layer 326 has the same polarity as the second conductive layer 313. The third conductive layer 325 and the fourth conductive layer 326 are spaced apart. In this embodiment, the third conductive layer 325 and the fourth conductive layer 326 are located on opposite sides of the second connecting portion 324 in the third direction D3. The third conductive layer 325 is bonded to the first conductive layer 312, and the fourth conductive layer 326 is bonded to the second conductive layer 313, thereby achieving a conductive connection between the first electrode assembly 310 and the second electrode assembly 320. This structural design eliminates the need for conductive connecting pieces or other conductive components between the first electrode assembly 310 and the second electrode assembly 320, which helps to reduce the internal space occupied by the electrode assembly in the housing 100, thereby improving the space utilization rate of the housing 100 and increasing the energy density of the battery cell.

[0054] In this embodiment, the first conductive layer 312 and the third conductive layer 325 are both positive conductive layers, and the second conductive layer 313 and the fourth conductive layer 326 are both negative conductive layers. Of course, in other embodiments, the first conductive layer 312 and the third conductive layer 325 can also be both negative conductive layers, and the second conductive layer 313 and the fourth conductive layer 326 can be both positive conductive layers.

[0055] The first electrode assembly 310 includes a first positive electrode, a first separator, and a first negative electrode, which are stacked sequentially along the second direction D2. The first positive electrode located on one side of the first connecting portion 311 protrudes from the first negative electrode along the direction of the first electrode assembly 310 toward a second electrode assembly 320 and is connected to the first conductive layer 312. The first negative electrode located on the other side of the first connecting portion 311 protrudes from the first positive electrode along the direction of the first electrode assembly 310 toward the first and second electrode assemblies 320 and is connected to the second conductive layer 313. The second electrode assembly 320 includes a second positive electrode, a second separator, and a second negative electrode. The second positive electrode, the second separator, and the second negative electrode are stacked sequentially along the second direction D2. The second positive electrode located on one side of the second connection portion 324 protrudes from the second negative electrode in the direction from the second electrode assembly 320 toward the first electrode assembly 310 and is connected to the third conductive layer 325. The second negative electrode located on the other side of the second connection portion 324 protrudes from the second positive electrode in the direction from the second electrode assembly 320 toward the first electrode assembly 310 and is connected to the fourth conductive layer 326, thereby achieving a conductive connection between the first electrode assembly 310 and the second electrode assembly 320.

[0056] Optionally, the second electrode assembly 320 includes an electrode assembly body 321 and a first protrusion 322. The first protrusion 322 protrudes from the side wall of the electrode assembly body 321 in the second direction D2. The wall of the housing 100 in the second direction D2 is a limiting wall 120. The limiting wall 120 has two first limiting grooves 121 on the side facing the electrode assembly. The two first limiting grooves 121 correspond one-to-one with the first protrusions 322 of the two second electrode assemblies 320. Each first protrusion 322 is insulated and embedded in a corresponding first limiting groove 121. By limiting the first protrusions 322 through the first limiting grooves 121, the housing 100 limits the second electrode assembly 320, preventing the second electrode assembly 320 from shifting relative to the first electrode assembly 310. This improves the reliability of the connection between the second electrode assembly 320 and the first electrode assembly 310. Furthermore, this structure can also reduce the probability of the electrode assembly moving or shifting within the housing 100. On the other hand, the first protrusion 322 increases the volume of the second electrode assembly 320, thereby increasing the volume of the electrode assembly and improving its capacity, which is beneficial for meeting the high-rate fast charging requirements of individual battery cells. Furthermore, the first protrusion 322 forms a reinforcing structure on the electrode assembly body 321, which helps improve the structural strength of the second electrode assembly 320, specifically increasing the structural strength of the non-central portion along the length of the electrode assembly. This further enhances the overall structural strength of the electrode assembly and reduces the likelihood of deformation.

[0057] Furthermore, on the same second electrode assembly 320, there are two first protrusions 322, and the two first protrusions 322 are arranged opposite each other along the second direction D2. There are also two limiting walls 120, which are arranged opposite each other along the second direction D2. Thus, the housing 100 can limit the second electrode assembly 320 on both sides in the second direction D2. This structure improves the uniformity of force on the second electrode assembly 320, thereby reducing the probability of the second electrode assembly 320 shifting relative to the first electrode assembly 310 due to uneven force. In addition, the fact that the same second electrode assembly 320 has first protrusions 322 on both sides in the second direction D2 further increases the volume of the second electrode assembly 320 and the electrode assembly, thereby further increasing the capacity of the electrode assembly and helping to meet the requirements of high-rate fast charging of individual battery cells.

[0058] Optionally, the first protrusion 322 extends from one end of the pole assembly body 321 along the first direction D1 to the other end, thereby improving the limiting effect of the housing 100 on the second pole assembly body 320 and further increasing the volume of the pole assembly, thus further increasing the capacity of the pole assembly. In addition, the first protrusion 322 forms a reinforcing rib on the pole assembly body 321, which is beneficial to further improving the structural strength of the second pole assembly body 320 and the pole assembly.

[0059] Optionally, such as Figures 1 to 6As shown, the second electrode assembly 320 also includes a capacity-enhancing structure 323, which protrudes from one end of the electrode assembly body 321 away from the first electrode assembly 310; there are two openings 110 and two cover plate assemblies 200, which correspond one-to-one, and the two cover plate assemblies 200 are located on both sides of the housing 100 in the first direction D1; the cover plate assembly 200 is provided with a limiting groove structure 210 on the side facing the housing 100, and the two cover plate assemblies 200 correspond one-to-one with the two second electrode assemblies 320, and the capacity-enhancing structure 323 of each second electrode assembly 320 is insulated and embedded in the limiting groove structure 210 of the corresponding cover plate assembly 200. This achieves the limiting of the second electrode assembly 320 by the cover plate assembly 200. On the one hand, it prevents the second electrode assembly 320 from shifting relative to the first electrode assembly 310, thus improving the reliability of the connection between the second electrode assembly 320 and the first electrode assembly 310. On the other hand, it also reduces the probability of the electrode assembly shifting or moving within the housing 100. In addition, the capacity-enhancing structure 323 increases the volume of the second electrode assembly 320 and the electrode assembly, thereby increasing the capacity of the electrode assembly and meeting the requirements of high-rate fast charging of individual battery cells.

[0060] Furthermore, the capacity-enhancing structure 323 includes a second protrusion 3231 and two third protrusions 3232. The two third protrusions 3232 are located on both sides of the second protrusion 3231 in the third direction D3. A tab 330 is provided on the side of the second protrusion 3231 facing away from the electrode assembly body 321. On the same second electrode assembly body 320, along the direction of the second electrode assembly body 320 facing away from the first electrode assembly body 310, the third protrusion 3232 protrudes from the tab 330, and both sides of the third protrusion 3232 protrude from the tab 330 in the second direction D2. This allows the third protrusion 3232 to protect the tab 330, reducing the probability of the tab 330 being bumped during the manufacturing process.

[0061] Furthermore, a second conductive plate 220 is provided within the limiting groove structure 210, and the second conductive plate 220 is connected to the tab 330. Multiple tabs 330 are provided on the same second protrusion 3231; for example, the number of tabs 330 on the same second protrusion 3231 can be two, three, or four. Increasing the number of tabs 330 can increase the flow rate between the electrode assembly and the cover plate assembly 200, thereby helping to meet the requirements of high-rate fast charging of individual battery cells. In addition, during charging and discharging of the battery cell, the heat at the tabs 330 is relatively concentrated. In this embodiment, by increasing the number of tabs 330, the heat is distributed to multiple tabs 330, which helps to reduce the risk of thermal runaway of the battery cell.

[0062] Furthermore, on the same second protrusion 3231, multiple tabs 330 are evenly distributed along the third direction D3, making the heat on the second protrusion 3231 more uniform.

[0063] Optionally, on the same second electrode assembly 320, the opposing surfaces of the two third protrusions 3232 are flush with the two side surfaces of the electrode assembly body 321 in the third direction D3, and the two side surfaces of the third protrusions 3232 in the second direction D2 are flush with the two side surfaces of the electrode assembly body 321 in the second direction D2. This maximizes the volume of the third protrusions 3232, thereby improving their structural strength and the fit between them and the limiting groove structure 210, enhancing the limiting effect of the cover assembly 200 on the second electrode assembly 320. Furthermore, it increases the volume of both the second electrode assembly 320 and the electrode assembly, thereby increasing the capacity of the electrode assembly.

[0064] Optionally, on the same second pole assembly 320, the second protrusion 3231 is connected to two third protrusions 3232 on both sides of the third direction D3, so that the second protrusion 3231 and the two third protrusions 3232 form a mutual support function, thereby improving the structural strength of the capacity expansion structure 323 and thus improving the limiting effect of the cover plate assembly 200 on the capacity expansion structure 323.

[0065] Optionally, such as Figures 1 to 8 As shown, the cover plate assembly 200 includes a cover plate 270, which includes a first cover body 271 and two second cover bodies 272. The two second cover bodies 272 are respectively connected to the two sides of the first cover body 271 on the third direction D3. The first cover body 271 and the two second cover bodies 272 are both protruding in the direction away from the housing 100 of the cover plate assembly 200. The first cover body 271 forms a second limiting groove 211 on the side facing the housing 100, and the second cover body 272 forms a third limiting groove 212 on the side facing the housing 100. The two sides of the second limiting groove 211 on the third direction D3 are respectively connected to the third limiting grooves 212 of the two second cover bodies 272 to form a limiting groove structure 210. The second limiting groove 211 conforms to the shape of the second protrusion 3231, and the second protrusion 3231 is insulatedly embedded within the second limiting groove 211. Two third protrusions 3232 correspond one-to-one with the third limiting grooves 212 of the two second covers 272. Each third limiting groove 212 conforms to the shape of a corresponding third protrusion 3232, and each third protrusion 3232 is insulatedly embedded within its corresponding third limiting groove 212. This creates the effect that the second limiting groove 211 limits the second protrusion 3231, and each third limiting groove 212 limits its corresponding third protrusion 3232. The second conductive plate 220 is insulatedly connected to the bottom and inner wall of the second limiting groove 211 via the second insulating member 250.

[0066] Furthermore, the cover assembly 200 also includes a first insulating member 230 and a first conductive plate 240. The first insulating member 230 covers the side of the first cover 271 facing away from the housing 100. The first conductive plate 240 is connected to the side of the first insulating member 230 facing away from the first cover 271, and the first conductive plate 240 is used to connect with a tab (not shown in the figure). Along the direction of the cover assembly 200 facing away from the housing 100, a second cover 272 protrudes from the first insulating member 230, the first conductive plate 240, and the tab, so that the second cover 272 protects the first insulating member 230, the first conductive plate 240, and the tab, reducing the probability of the first insulating member 230, the first conductive plate 240, and the tab being bumped during the manufacturing process.

[0067] Furthermore, the second cover 272 protrudes from the first conductive plate 240 on both sides of the second direction D2, thereby realizing the protective function of the second cover 272 on the first conductive plate 240 in the second direction D2.

[0068] Furthermore, the cover plate assembly 200 also includes a conductive post 260, one end of which is connected to the second conductive plate 220, and the other end passes through the second insulating member 250, the first cover body 271, the first insulating member 230, and is connected to the first conductive plate 240, thereby making the second conductive plate 220 electrically connected to the first conductive plate 240 through the conductive post 260.

[0069] Optionally, the second protrusion 3231 is provided with a first plane 3231a and two first slopes 3231b. The first plane 3231a is located on the side of the second protrusion 3231 away from the electrode assembly body 321. The two first slopes 3231b are respectively connected to the two sides of the first plane 3231a in the second direction D2, and along the direction of the first plane 3231a away from the electrode assembly body 321, the two first slopes 3231b are inclined in a direction that approaches each other. The design of the two first slopes 3231b can increase the mating area between the second protrusion 3231 and the limiting groove structure 210, thereby improving the limiting effect of the cover plate assembly 200 on the second electrode assembly body 320. The third protrusion 3232 is provided with a second plane 3232a and two second slopes 3232b. The second plane 3232a is located on the side of the third protrusion 3232 away from the electrode assembly body 321. The two second slopes 3232b are respectively connected to the two sides of the second plane 3232a in the second direction D2, and along the direction of the second plane 3232a away from the electrode assembly body 321, the two second slopes 3232b are inclined in a direction that approaches each other. The design of the two second slopes 3232b can increase the mating area between the third protrusion 3232 and the limiting groove structure 210, thereby improving the limiting effect of the cover plate assembly 200 on the second electrode assembly body 320.

[0070] Optionally, such as Figures 1 to 9 As shown, the tab 330 includes a first tab body 331 and two second tab bodies 332. The first tab body 331 is located on a first plane 3231a and extends along a second direction D2 to both sides of the first plane 3231a. The two second tab bodies 332 correspond one-to-one with two first slopes 3231b. Each second tab body 332 is located on a corresponding first slope 3231b and extends along the inclination direction of the corresponding first slope 3231b. One end of the second tab body 332 is connected to the first tab body 331, and the other end extends to the side of the first slope 3231b opposite to the first plane 3231a. This structure can increase the volume of a single tab 330, thereby increasing the connection area and current flow area between the tab 330 and the second conductive plate 220, which is beneficial to further increase the current flow between the electrode group and the cover plate assembly 200 to meet the requirements of high-rate fast charging of the battery cells. In addition, this structure can expand the dispersion area of ​​a single tab 330, which is beneficial for the rapid heat dissipation of the tab 330.

[0071] In this embodiment, on the same second electrode assembly 320, two third protrusions 3232 are symmetrically arranged about the middle of the second protrusion 3231 in the third direction D3, so as to reduce the molding difficulty of the capacity-enhancing structure 323 and reduce the assembly difficulty of the electrode assembly and the cover plate assembly 200, thereby improving the production yield and the assembly yield.

[0072] Optionally, such as Figures 1 to 11As shown, the dimension of the pole assembly in the first direction D1 is E, that is, the distance between the opposite sides of the third protrusions 3232 of the two second pole assembly bodies 320 in the first direction D1 is E, and the dimension of the first pole assembly body 310 in the first direction D1 is F, 0.29≤F / E≤0.59. For example, F / E can be 0.29, 0.33, 0.45, 0.5 or 0.59, etc. If F / E<0.29, then with E unchanged, F is too small, which will extend the length dimension of the second pole assembly body 320 (that is, the dimension of the second pole assembly body 320 in the first direction D1), which will reduce the structural strength of the second pole assembly body 320, thereby increasing the risk of the pole assembly bending deformation. Furthermore, since the dimension of the first electrode assembly 310 in the second direction D2 is larger than that of the second electrode assembly 320 in the second direction D2, it achieves the effect of thickening at the middle position in the length direction of the electrode assembly. If the length dimension of the first electrode assembly 310 is too small, the thickened area at the middle position in the length direction of the electrode assembly will be too small. This will reduce the expansion of the electrode assembly volume, and consequently reduce the increase in electrode assembly capacity, which is not conducive to meeting the requirements of high-rate fast charging of battery cells. If F / E > 0.59, then with E remaining constant, F is too large, that is, the length dimension of the first electrode assembly 310 is too large. This will reduce the structural strength of the first electrode assembly 310 and increase the probability of deformation problems at the middle position in the length direction of the electrode assembly. Furthermore, the limiting wall 120, positioned opposite to the first electrode assembly 310, protrudes in a direction away from the first electrode assembly 310 to form a raised portion 122. A fourth limiting groove is formed on the side of the raised portion 122 facing the first electrode assembly. On the same limiting wall 120, the fourth limiting groove communicates with two first limiting grooves 121 on both sides in the first direction D1. The portion of the first electrode assembly 310 protruding along the second direction D2 is insulated and embedded in the fourth limiting groove to achieve the limiting effect of the housing 100 on the first electrode assembly 310, thereby improving the stability of the connection between the first electrode assembly 310 and the second electrode assembly 320 and preventing the electrode assembly from moving within the housing 100. If the length of the first electrode assembly 310 is too large, the size of the raised portion 122 in the first direction D1 will also be too large. This will increase the manufacturing difficulty and cost of the housing 100, and will also reduce the structural strength of the limiting wall 120, increasing the probability of deformation of the housing 100.

[0073] Optionally, the dimension of the second plane 3232a in the second direction D2 is W1. On the same third protrusion 3232, the distance between the opposite sides of the two second slopes 3232b in the second direction D2 is W2, where 0.41≤W1 / W2≤0.79. For example, W1 / W2 can be 0.41, 0.5, 0.63, 0.75, or 0.79, etc. If W1 / W2<0.41, then with W2 unchanged, W1 is too small. This will make the side of the third protrusion 3232 away from the electrode assembly body 321 relatively narrow, reducing the structural strength of the third protrusion 3232, and thus reducing the limiting effect of the third limiting groove 212 on the third protrusion 3232. In addition, a small W1 will also reduce the volume of the third protrusion 3232, thereby reducing the expansion of the electrode assembly volume and reducing the increase in electrode assembly capacity, which is not conducive to meeting the requirements of high-rate fast charging of battery cells. If W1 / W2 > 0.79, then with W2 remaining constant, W1 becomes too large. This reduces the inclination of the second slope 3232b, making it closer to being parallel to the first direction D1. Consequently, it reduces the mating area between the third protrusion 3232 and the third limiting groove 212, thus decreasing the limiting effect of the third limiting groove 212 on the third protrusion 3232. Furthermore, if W1 is too large, the inclination angle of the two sidewalls of the second cover 272 in the second direction D2 will decrease. This reduces the size of the second cover 272 protruding from the first conductive plate 240 in the second direction D2, thereby reducing the protective effect of the second cover 272 on the first conductive plate 240.

[0074] Optionally, the dimension of the electrode assembly in the third direction D3 is B, and the dimension of the second protrusion 3231 in the third direction D3 is L1. That is, on the same second electrode assembly body 320, the dimension of the side of the two third protrusions 3232 facing each other in the third direction D3 is L1, where 0.36≤L1 / B≤0.64. For example, L1 / B can be 0.36, 0.4, 0.55, 0.6, or 0.64, etc. If L1 / B < 0.36, then with B remaining unchanged, L1 is too small, which will reduce the installation space of the electrode tab 330, thereby making the electrode tabs 330 on the second protrusion 3231 more concentrated. During the charging and discharging of a single battery cell, the heat on the second protrusion 3231 is relatively concentrated, increasing the risk of thermal runaway of the battery cell. Furthermore, the second limiting groove 211 conforms to the shape of the second protrusion 3231. If L1 is too small, the size of the first cover 271 in the third direction D3 will be too small. This will reduce the installation space of the first conductive plate 240 on the first cover 271, thus reducing the size of the first conductive plate 240 in the third direction D3. This reduces the connection area and current flow area between the first conductive plate 240 and the electrode, lowering the current flow capacity of the cover assembly 200, which is detrimental to meeting the high-rate fast charging requirements of the battery cell. If L1 / B > 0.64, then with B unchanged, L1 is too large. This will reduce the size of the third protrusion 3232 in the third direction D3, thus reducing the structural strength of the third protrusion 3232 and reducing the limiting effect of the third limiting groove 212 on the third protrusion 3232. Furthermore, on the same second electrode assembly 320, along the direction of the second electrode assembly 320 away from the first electrode assembly 310, the third protrusion 3232 protrudes from the second protrusion 3231. If the size of the third protrusion 3232 in the third direction D3 is too small, it will reduce the increase in electrode assembly volume and electrode assembly capacity, which is not conducive to meeting the high-rate fast charging requirements of battery cells.

[0075] Optionally, the first electrode assembly 310 protrudes from the second direction D2 by a dimension H1, where 5mm≤H1≤35mm. For example, H1 can be 5mm, 10mm, or 35mm, which can both increase the thickness of the middle part in the length direction of the electrode assembly and keep the manufacturing difficulty of the housing 100 at a low level, thereby improving production efficiency and yield.

[0076] Optionally, on the same second pole assembly 320, the distance between the side of the second slope 3232b facing away from the second plane 3232a and the side of the pole assembly body 321 facing away from the first pole assembly 310 is H2, where 5mm ≤ H2 ≤ 20mm. For example, H2 can be 5mm, 15mm, or 20mm, etc. This ensures that the third protrusion 3232 has sufficient structural strength and sufficient volume to allow the pole assembly to have a sufficient capacity increase.

[0077] Optionally, on the same second electrode assembly 320, the third protrusion 3232 protrudes from the second protrusion 3231 by a dimension H3 along the direction from the first electrode assembly 310 to the second electrode assembly 320. That is, on the same second electrode assembly 320, the distance between the first plane 3231a and the second plane 3232a in the first direction D1 is H3, 12mm≤H3≤25mm. For example, H3 can be 12mm, 20mm, or 25mm, etc. This ensures that the third protrusion 3232 has sufficient structural strength and can also ensure that the third protrusion 3232 can provide reliable protection for the electrode tab 330.

[0078] Optionally, the first protrusion 322 has a dimension of L2 in the third direction D3, where 4mm ≤ L1-L2 ≤ 10mm. For example, L1-L2 can be 4mm, 6.5mm, or 10mm, etc.

[0079] Optionally, the dimension of the second electrode assembly 320 in the second direction D2 is A, that is, the distance between the two first protrusions 322 on the same second electrode assembly 320 on opposite sides in the second direction D2 is A, 30mm≤A≤118mm. For example, A can be 30mm, 55mm or 118mm, etc.

[0080] Optionally, 16mm≤A-W2≤70mm, for example, A-W2 can be 16mm, 55mm or 70mm, etc.

[0081] Optionally, the included angle between the two second slopes 3232b of the same third protrusion 3232 is N, 50°≤N≤90°. For example, N can be 50°, 75° or 90°, which can ensure that the third protrusion 3232 has sufficient structural strength so that the third limiting groove 212 can provide a reliable limiting effect on the third protrusion 3232, and also enable the second cover 272 to provide a reliable protection for the first conductive plate 240.

[0082] In this embodiment, the electrode assembly is manufactured using a lamination process and a die-cutting process, and the electrode tab 330 and the second conductive plate 220, the conductive post 260 and the first conductive plate 240 are connected using an ultrasonic welding process. The lamination process, the die-cutting process and the ultrasonic welding process are all common production processes in the art, which are conducive to realizing mass automated production.

[0083] Table 1 below provides six sets of embodiments and six sets of comparative examples. In all six sets of embodiments and six sets of comparative examples, the housing 100 is made of aluminum, the insulating film wrapped around the outer surface of the electrode group is polypropylene (PP) film, the first insulating element 230 is made of polyphenylene sulfide (PPS) material, and the second insulating element 250 is made of PP material.

[0084]

[0085] In Example 1, H1 is 5mm, H2 is 5mm, H3 is 12mm, F / E is 0.33, L1 / B is 0.4, L1-L2 is 4mm, A-W2 is 16mm, W1 / W2 is 0.5, N is 50°, A is 30mm, and the yield rate of the battery cells is >98%. No problems were found with low strength of the electrode assembly structure, or abnormal assembly of the electrode assembly, casing 100, and cover plate assembly 200. There were no damage or deformation issues with the electrode assembly or tabs 330. The overcurrent capacity of tabs 330, the capacity of the electrode assembly, and the temperature of tabs 330 all meet the high-rate fast charging requirements of the battery cells.

[0086] In Example 2, H1 is 12mm, H2 is 8mm, H3 is 16mm, F / E is 0.37, L1 / B is 0.45, L1-L2 is 5mm, A-W2 is 24mm, W1 / W2 is 0.57, N is 55°, and A is 52mm. The yield rate of the battery cells is >98%. No problems were found with low strength of the electrode assembly structure, or abnormal assembly of the electrode assembly, casing 100, and cover plate assembly 200. There were no damage or deformation issues with the electrode assembly or tabs 330. The overcurrent capacity of tabs 330, the capacity of the electrode assembly, and the temperature of tabs 330 all meet the requirements of high-rate fast charging for the battery cells.

[0087] In Example 3, H1 is 20mm, H2 is 11mm, H3 is 20mm, F / E is 0.4, L1 / B is 0.5, L1-L2 is 6mm, A-W2 is 36mm, W1 / W2 is 0.6, N is 60°, A is 70mm, and the yield rate of the battery cells is >98%. No problems were found with low strength of the electrode assembly structure, or abnormal assembly of the electrode assembly, casing 100, and cover plate assembly 200. There were no damage or deformation issues with the electrode assembly or tabs 330. The overcurrent capacity of tabs 330, the capacity of the electrode assembly, and the temperature of tabs 330 all meet the high-rate fast charging requirements of the battery cells.

[0088] In Example 4, H1 is 27mm, H2 is 14mm, H3 is 20mm, F / E is 0.46, L1 / B is 0.53, L1-L2 is 7mm, A-W2 is 48mm, W1 / W2 is 0.66, N is 70°, and A is 82mm. The yield rate of the battery cells is >98%. No problems were found with low strength of the electrode assembly structure, or abnormal assembly of the electrode assembly, casing 100, and cover plate assembly 200. There were no damage or deformation issues with the electrode assembly or tabs 330. The overcurrent capacity of tabs 330, the capacity of the electrode assembly, and the temperature of tabs 330 all meet the requirements of high-rate fast charging for the battery cells.

[0089] In Example 5, H1 is 32mm, H2 is 16mm, H3 is 22mm, F / E is 0.5, L1 / B is 0.56, L1-L2 is 8mm, A-W2 is 60mm, W1 / W2 is 0.71, N is 80°, A is 100mm, and the yield rate of the battery cells is >98%. No problems were found with low strength of the electrode assembly structure, or abnormal assembly of the electrode assembly, casing 100, and cover plate assembly 200. There were no damage or deformation issues with the electrode assembly or tabs 330. The overcurrent capacity of tabs 330, the capacity of the electrode assembly, and the temperature of tabs 330 all meet the high-rate fast charging requirements of the battery cells.

[0090] In Example 6, H1 is 35mm, H2 is 20mm, H3 is 25mm, F / E is 0.55, L1 / B is 0.6, L1-L2 is 10mm, A-W2 is 70mm, W1 / W2 is 0.75, N is 90°, and A is 118mm. The yield rate of the battery cells is >98%. No problems were found with low strength of the electrode assembly structure, or abnormal assembly of the electrode assembly, casing 100, and cover plate assembly 200. There were no damage or deformation issues with the electrode assembly or tabs 330. The overcurrent capacity of tabs 330, the capacity of the electrode assembly, and the temperature of tabs 330 all meet the requirements of high-rate fast charging for the battery cells.

[0091] In Comparative Example 1, H1 is 20mm, H2 is 11mm, H3 is 20mm, F / E is 0.28, L1 / B is 0.5, L1-L2 is 6mm, A-W2 is 36mm, W1 / W2 is 0.6, N is 60°, A is 70mm, and the yield rate of individual battery cells is <98%. The second electrode assembly has low structural strength (320). The capacity increase of the electrode assembly is small and cannot meet the requirements of high-rate fast charging of individual battery cells.

[0092] In Comparative Example 2, H1 is 20mm, H2 is 11mm, H3 is 20mm, F / E is 0.6, L1 / B is 0.5, L1-L2 is 6mm, A-W2 is 36mm, W1 / W2 is 0.6, N is 60°, A is 70mm, and the yield rate of individual battery cells is <98%; the first electrode assembly 310 has low structural strength. The casing 100 is difficult and costly to manufacture, and the limiting wall 120 has low structural strength.

[0093] In Comparative Example 3, H1 is 20mm, H2 is 11mm, H3 is 20mm, F / E is 0.4, L1 / B is 0.35, L1-L2 is 6mm, A-W2 is 36mm, W1 / W2 is 0.6, N is 60°, A is 70mm, and the yield of the battery cell is <98%. During the charging and discharging of the battery cell, the heat is concentrated on the second protrusion 3231, the current-carrying area of ​​the first conductive plate 240 and the plate is small, and the current-carrying capacity of the cover assembly 200 is poor, which cannot meet the high-rate fast charging requirements of the battery cell.

[0094] In Comparative Example 4, H1 is 20mm, H2 is 11mm, H3 is 20mm, F / E is 0.4, L1 / B is 0.65, L1-L2 is 6mm, A-W2 is 36mm, W1 / W2 is 0.6, N is 60°, A is 70mm, and the yield rate of the battery cell is <98%. The third protrusion 3232 has low structural strength, and the third limiting groove 212 has a poor limiting effect on the third protrusion 3232. The increase in electrode group capacity is small and cannot meet the high-rate fast charging requirements of the battery cell.

[0095] In Comparative Example 5, H1 is 20mm, H2 is 11mm, H3 is 20mm, F / E is 0.4, L1 / B is 0.5, L1-L2 is 6mm, A-W2 is 36mm, W1 / W2 is 0.4, N is 60°, and A is 70mm. The yield rate of the battery cell is <98%. The third protrusion 3232 has low structural strength, and the third limiting groove 212 has a poor limiting effect on the third protrusion 3232. The increase in electrode group capacity is small and cannot meet the requirements of high-rate fast charging of battery cells.

[0096] In Comparative Example 6, H1 is 20mm, H2 is 11mm, H3 is 20mm, F / E is 0.4, L1 / B is 0.5, L1-L2 is 6mm, A-W2 is 36mm, W1 / W2 is 0.8, N is 60°, A is 70mm, and the yield rate of the single battery cell is <98%. The third limiting groove 212 has a poor limiting effect on the third protrusion 3232. The second cover 272 has a poor protective effect on the first conductive plate 240.

[0097] It can be seen that when 5mm≤H1≤35mm, 5mm≤H2≤20mm, 12mm≤H3≤25mm, 0.29≤F / E≤0.59, 0.36≤L1 / B≤0.64, 50°≤N≤90°, 4mm≤L1-L2≤10mm, 16mm≤A-W2≤70mm, 0.41≤W1 / W2≤0.79, and 30mm≤A≤118mm, the structural strength of the first electrode assembly 310 and the second electrode assembly 320 can be improved, thereby increasing the structural strength of the electrode assembly, expanding the volume of the electrode assembly, and thus increasing the capacity of the electrode assembly to meet the requirements of high-rate fast charging of individual battery cells.

[0098] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A battery cell, characterized by, The application relates to a battery pack, comprising: a shell (100), a length direction of the shell (100) being a first direction (D1), one of a width direction of the shell (100) and a thickness direction of the shell (100) being a second direction (D2); a cover plate assembly (200) covering an opening (110) of the shell (100); a pole group, the pole group comprising a first pole group body (310) and two second pole group bodies (320), the two second pole group bodies (320) being respectively located on two sides of the first pole group body (310) in the first direction (D1), and the two second pole group bodies (320) being connected with the first pole group body (310) in a split manner, a size of the first pole group body (310) in the second direction (D2) being greater than a size of the second pole group body (320) in the second direction (D2).

2. The battery cell of claim 1, wherein, The second pole group body (320) comprises a pole group body (321) and a first protruding part (322), the first protruding part (322) being protruded on a side wall of the pole group body (321) in the second direction (D2); a wall of the shell (100) in the second direction (D2) is a limiting wall (120), the limiting wall (120) being provided with two first limiting grooves (121) on a side of the limiting wall (120) facing the pole group, the two first limiting grooves (121) corresponding to the first protruding parts (322) of the two second pole group bodies (320) in a one-to-one manner, and each first protruding part (322) is respectively and independently embedded in a corresponding first limiting groove (121).

3. The battery cell of claim 2, wherein, The second pole group body (320) further comprises a capacity-increasing structure (323), the capacity-increasing structure (323) being protruded on an end of the pole group body (321) away from the first pole group body (310); the number of the opening (110) and the cover plate assembly (200) is two and the opening (110) and the cover plate assembly (200) correspond to each other in a one-to-one manner, the two cover plate assemblies (200) being respectively located on two sides of the shell (100) in the first direction (D1); the cover plate assembly (200) is provided with a limiting groove structure (210) on a side of the cover plate assembly (200) facing the shell (100), the two cover plate assemblies (200) corresponding to the two second pole group bodies (320) in a one-to-one manner, and the capacity-increasing structure (323) of each second pole group body (320) is respectively and independently embedded in the limiting groove structure (210) of a corresponding cover plate assembly (200).

4. The battery cell of claim 3, wherein, The other one of the width direction of the shell (100) and the thickness direction of the shell (100) is a third direction (D3); the capacity-increasing structure (323) comprises a second protruding portion (3231) and two third protruding portions (3232), the two third protruding portions (3232) are respectively located on both sides of the second protruding portion (3231) in the third direction (D3), a tab (330) is arranged on the side of the second protruding portion (3231) away from the pole group body (321), on the same second pole group body (320), in the direction in which the second pole group body (320) is away from the first pole group body (310), the third protruding portion (3232) protrudes from the tab (330), and the third protruding portion (3232) protrudes from the tab (330) on both sides in the second direction (D2).

5. The battery cell of claim 4, wherein, The second protruding portion (3231) is provided with a first plane (3231a) and two first inclined surfaces (3231b), the first plane (3231a) is located on the side of the second protruding portion (3231) away from the pole group body (321), the two first inclined surfaces (3231b) are respectively connected to both sides of the first plane (3231a) in the second direction (D2), and in the direction in which the first plane (3231a) is away from the pole group body (321), the two first inclined surfaces (3231b) are inclined in directions approaching each other; The third protruding portion (3232) is provided with a second plane (3232a) and two second inclined surfaces (3232b), the second plane (3232a) is located on the side of the third protruding portion (3232) away from the pole group body (321), the two second inclined surfaces (3232b) are respectively connected to both sides of the second plane (3232a) in the second direction (D2), and in the direction in which the second plane (3232a) is away from the pole group body (321), the two second inclined surfaces (3232b) are inclined in directions approaching each other.

6. The battery cell of claim 5, wherein, The tab (330) comprises a first tab body (331) and two second tab bodies (332), the first tab body (331) is located on the first plane (3231a) and extends to both sides of the first plane (3231a) in the second direction (D2), the two second tab bodies (332) correspond to the two first inclined surfaces (3231b) one by one, each second tab body (332) is located on a corresponding first inclined surface (3231b), and each second tab body (332) extends along the inclined direction of the corresponding first inclined surface (3231b), one end of the second tab body (332) is connected with the first tab body (331), and the other end extends to the side of the first inclined surface (3231b) away from the first plane (3231a); And / or, the limiting groove structure (210) is internally provided with a second conductive plate (220), the second conductive plate (220) is connected with the tab (330), and a plurality of tabs (330) are arranged on the same second protruding part (3231).

7. The battery cell of claim 5, wherein, The size of the second plane (3232a) in the second direction (D2) is W1, the distance between the two second slope surfaces (3232b) on the same third protruding part (3232) in the second direction (D2) is W2, and 0.41≤W1 / W2≤0.

79.

8. The battery cell of any one of claims 4-7, wherein, The size of the pole group in the third direction (D3) is B, the size of the second protruding part (3231) in the third direction (D3) is L1, and 0.36≤L1 / B≤0.

64.

9. The battery cell of any one of claims 2-7, wherein, The number of the first protruding parts (322) on the same second pole group body (320) is two, and the two first protruding parts (322) are oppositely arranged along the second direction (D2), and the number of the limiting walls (120) is two, and the two limiting walls (120) are oppositely arranged along the second direction (D2). And / or, the first protruding part (322) extends from one end to the other end of the pole group body (321) along the first direction (D1).

10. The battery cell of any one of claims 1-7, wherein, The size of the pole group in the first direction (D1) is E, the size of the first pole group body (310) in the first direction (D1) is F, and 0.29≤F / E≤0.59.

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