Cover plate assembly, battery and battery pack

Abstract

This application provides a cover plate assembly, a battery, and a battery pack, relating to the field of battery technology. The cover plate assembly includes a cover plate, terminals, and a seal. The cover plate includes a cover plate body, two first flanges, and two second flanges. The terminals are fixed to mounting holes in the cover plate body by the first and second flanges. The seal is at least partially disposed between the terminals and the cover plate. In a third direction, the area of ​​the end face of the terminal away from the cover plate body is S1; the overlapping area of ​​the projection of the terminal and the projection of the first flange is S2; the overlapping area of ​​the projection of the seal between the first flange and the cover plate body and the projection of the cover plate body is S3; and the overlapping area of ​​the projection of the terminal and the projection of the cover plate body is S4. By ensuring that (S2 / S1)×(S3 / S4) is greater than or equal to 0.01 and less than or equal to 0.3, the fixing effect of the first flange on the terminals can be improved, making assembly failure between the cover plate and the terminals less likely, thereby ensuring the sealing between the terminals and the cover plate.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more particularly to a cover plate assembly, a battery, and a battery pack. Background Technology

[0002] With the increasing need for fast charging in electric vehicles, high-voltage fast charging technology has become a key direction for industry development. To achieve high-voltage output, the battery pack uses multiple batteries connected in series.

[0003] In related technologies, the battery cover assembly includes a cover plate and terminals with different length and width dimensions. A sealing ring and insulating adhesive are provided between the cover plate and the terminals. The cover plate is fixed to the terminals by riveting.

[0004] However, the assembly between the cover plate and the pole post is prone to failure, leading to sealing failure. Summary of the Invention

[0005] This application provides a cover plate assembly, a battery, and a battery pack to solve the problem of easy assembly failure between the cover plate and the terminal post, leading to sealing failure.

[0006] In a first aspect, embodiments of this application provide a cover plate assembly, including:

[0007] A cover plate, the cover plate comprising a cover plate body, two first flanges and two second flanges, the cover plate body being provided with mounting holes, the two first flanges being disposed on opposite sides of the mounting holes in a first direction, and the two second flanges being disposed on opposite sides of the mounting holes in a second direction;

[0008] The pole is fixed in the mounting hole by the first flange and the second flange, the pole covers at least part of the mounting hole, and the ratio of the size of the pole in the second direction to the size of the pole in the first direction is greater than or equal to 1.5 and less than or equal to 8.

[0009] A sealing element is at least partially disposed between the pole and the cover plate;

[0010] In the second direction, the pole post includes a first portion located between the two ends of the first flange;

[0011] In the third direction, the area of ​​the end face of the pole away from the cover plate body is S1, the overlapping area of ​​the projection of the pole and the projection of the first flange is S2, the area of ​​the part of the sealing member located between the cover plate body and the first part of the pole is S3, and the overlapping area of ​​the projection of the pole and the projection of the cover plate body is S4.

[0012] S1, S2, S3, and S4 satisfy the following:

[0013] 0.01 ≤ (S2 / S1) × (S3 / S4) ≤ 0.3, where the units of S1, S2, S3, and S4 are all mm. 2 .

[0014] Secondly, embodiments of this application provide a battery, including a housing and a cover assembly as described in the first aspect; the cover assembly is connected to the housing.

[0015] Thirdly, embodiments of this application provide a battery pack including a plurality of batteries as described in the second aspect.

[0016] In the cover assembly, battery, and battery pack provided in this application embodiment, if (S2 / S1)×(S3 / S4) is less than 0.01, the overlapping area between the projection of the terminal post and the projection of the first flange in the third direction is too small, resulting in poor fixing effect of the first flange on the terminal post, making it easy for the cover plate and the terminal post to fail in assembly, leading to sealing failure. If (S2 / S1)×S3 / S4) is greater than 0.3, the overlapping area between the projection of the terminal post and the projection of the first flange in the third direction is too large, resulting in a reduced welding area between the terminal post and the busbar, leading to poor heat dissipation and poor current carrying capacity of the terminal post. By ensuring that (S2 / S1)×(S3 / S4) is greater than or equal to 0.01 and less than or equal to 0.3, the fixing effect of the first flange on the terminal post can be improved, making it less likely for the cover plate and the terminal post to fail in assembly, thereby ensuring the sealing between the terminal post and the cover plate. It can also increase the welding area between the terminal post and the busbar, thereby improving the heat dissipation performance and current carrying capacity of the terminal post. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of a battery provided in an embodiment of this application;

[0019] Figure 2 for Figure 1 A cross-sectional view of the battery in the diagram;

[0020] Figure 3a A top view schematic diagram of a first type of cover plate assembly provided in an embodiment of this application;

[0021] Figure 3b for Figure 3aA partial schematic diagram of the cover plate assembly;

[0022] Figure 4 for Figure 3a A cross-sectional view of section Y1-Y1 in the diagram;

[0023] Figure 5 for Figure 3a A cross-sectional view of section X1-X1 in the diagram;

[0024] Figure 6 for Figure 3a A top view of the pole in the diagram;

[0025] Figure 7 for Figure 6 A cross-sectional view at Y2-Y2 in the diagram;

[0026] Figure 8 This is a schematic diagram of the structure of the second cover plate assembly provided in the embodiments of this application;

[0027] Figure 9 for Figure 8 Enlarged diagram of point J in the diagram;

[0028] Figure 10 for Figure 8 A top view of the pole in the diagram;

[0029] Figure 11 for Figure 8 A schematic diagram of the pole structure in the diagram;

[0030] Figure 12 for Figure 10 A cross-sectional view at Y3-Y3 in the diagram;

[0031] Figure 13 for Figure 8 Cross-sectional view of the cover plate assembly Figure 1 ;

[0032] Figure 14 for Figure 8 Cross-sectional view of the cover plate assembly Figure 2 ;

[0033] Figure 15 This is a cross-sectional schematic diagram of a third cover plate assembly provided in an embodiment of this application.

[0034] Explanation of reference numerals in the attached figures:

[0035] 100-Cover plate assembly; 10-Cover plate; 11-Cover plate body; 111-Mounting hole; 12-First flange; 121-First connection; 13-Second flange; 131-Second connection; 14-Transition section; 20-Position post; 21-Position post body; 22-First protrusion; 221-First step; 23-Second protrusion; 231-Second step; 30-Seal; 301-First sidewall; 31-First sealing component; 32-Second sealing component; 200-Housing; 300-Battery cell; 1201-First vertical section; 1202-First horizontal section; 1301-Second vertical section; 1302-Second horizontal section. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0037] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0038] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "fixation," etc., 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, an electrical connection, or a connection that allows communication between components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0039] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0040] In the above description, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0041] As mentioned in the background section, assembly failure between the cover plate and the terminal post is prone to occur, leading to sealing failure. Research has found that this problem arises because the overlap area between the projection of the terminal post along the height direction and the projection of the flange corresponding to the long side of the terminal post is too small. This results in poor fixing effect of the flange corresponding to the long side of the terminal post on the terminal post, making assembly failure between the cover plate and the terminal post easy, leading to sealing failure.

[0042] To address the aforementioned issues, the cover assembly, battery, and battery pack provided in this application embodiment have the following features: in the height direction of the battery, the area of ​​the end face of the cover body on the side of the terminal post away from the cover is S1; the overlapping area of ​​the projection of the terminal post and the projection of the first flange is S2; the overlapping area of ​​the projection of the sealing element between the first flange and the cover body and the projection of the cover body is S3; and the overlapping area of ​​the projection of the terminal post and the projection of the cover body is S4. By ensuring that (S2 / S1)×(S3 / S4) is greater than or equal to 0.01 and less than or equal to 0.3, the fixing effect of the first flange on the terminal post can be improved, making it less prone to assembly failure between the cover and the terminal post, thereby ensuring the sealing performance between the terminal post and the cover.

[0043] The cover plate assembly, battery, and battery pack provided in this application will be described in detail below with reference to specific embodiments.

[0044] First, see Figure 1Let the length direction of the battery be defined as the X direction, i.e., the second X direction; let the width direction of the battery be defined as the Y direction, i.e., the first Y direction; and let the thickness direction of the battery be defined as the Z direction, i.e., the third Z direction. The first, second, and third directions are perpendicular to each other.

[0045] Firstly, see [the following] Figure 1 and Figure 2 As shown, this application provides a cover plate assembly 100 applied to a battery. The battery includes a housing 200, a cell 300, and a cover plate assembly 100. The cover plate assembly 100 is connected to the housing 200, and the cover plate assembly 100 and the housing 200 form a cavity. The cell 300 is disposed in the cavity, which is filled with electrolyte.

[0046] Cell 300 is the component in the battery where electrochemical reactions occur; it is the smallest unit in the battery capable of charging or discharging.

[0047] Cell 300 is the basic unit in a battery, typically including a positive electrode, a negative electrode, and a separator. For example, a lithium-ion cell primarily operates by the intercalation and deintercalation of lithium ions between the positive and negative electrodes.

[0048] The battery cell 300 can be cylindrical or cuboid. In a cylindrical battery cell, the positive electrode, negative electrode, and separator are wound into a cylindrical shape. In a cuboid battery cell, the positive electrode, negative electrode, and separator are wound or stacked into a roughly cuboid shape.

[0049] The housing 200 is a component used to provide a receiving space to house the battery cell and other components and isolate them from the outside environment. The housing 200 includes a body with an opening at at least one end and a receiving cavity. The opening of the housing 200 can be closed by a cover plate 10 to seal and isolate the internal environment of the battery from the external environment.

[0050] The material of the housing 200 includes, but is not limited to, copper, iron, aluminum, stainless steel or aluminum alloy.

[0051] In one possible implementation, see Figure 3a and Figure 3b As shown, the cover assembly 100 includes a cover 10.

[0052] The length direction of the cover plate 10 is the same as the length direction of the battery, the width direction of the cover plate 10 is the same as the width direction of the battery, and the thickness direction of the cover plate 10 is the same as the thickness direction of the battery.

[0053] The cover plate 10 is a component that closes the opening of the housing 200 to isolate the internal environment of the battery from the external environment.

[0054] The material of the cover plate 10 includes, but is not limited to, metals such as copper, iron, aluminum, stainless steel or aluminum alloy.

[0055] See Figure 4 and Figure 5 As shown, the cover plate 10 includes a cover plate body 11, two first flanges 12 and two second flanges 13.

[0056] The cover plate body 11 is provided with a mounting hole 111. The mounting hole 111 penetrates the cover plate body 11 in a third direction. The size of the mounting hole 111 in the second direction is larger than the size of the mounting hole 111 in the first direction.

[0057] In some examples, the cover body 11 is provided with two mounting holes 111, which are spaced apart along the second direction.

[0058] Two first flanges 12 are provided on opposite sides of the mounting hole 111 in a first direction. Two second flanges 13 are provided on opposite sides of the mounting hole 111 in a second direction.

[0059] The first flange 12 is larger in the second direction than the second flange 13 is in the first direction.

[0060] Both the first flange 12 and the second flange 13 are bent toward the center of the mounting hole 111. Both the first flange 12 and the second flange 13 are bent.

[0061] In the third direction, both the first flange 12 and the second flange 13 are located on the side of the cover body 11 away from the battery cell 300. Both the first flange 12 and the second flange 13 are connected to the cover body 11.

[0062] In some examples, the first flange 12 and / or the second flange 13 are integrally formed with the cover body 11. Specifically, the first flange 12 may be integrally formed with the cover body 11. Alternatively, the second flange 13 may be integrally formed with the cover body 11. Or, the first flange 12 and the second flange 13 may be integrally formed with the cover body 11.

[0063] In some examples, the first flange 12 and / or the second flange 13 are separate structures from the cover plate body 11. Specifically, the first flange 12 is a separate structure from the cover plate body 11, and the first flange 12 is connected to the cover plate body 11 by welding. Alternatively, the second flange 13 is a separate structure from the cover plate body 11, and the second flange 13 is connected to the cover plate body 11 by welding. Or, the first flange 12 and the second flange 13 are separate structures from the cover plate body 11, and the first flange 12 and the second flange 13 are connected to the cover plate body 11 by welding.

[0064] The cover plate 10 has a dimension of L1 in the second direction. The cover plate 10 has a dimension of L2 in the first direction.

[0065] In some examples, L1 is greater than or equal to 120mm and less than or equal to 350mm. For example, the value of L1 can be 120mm, 150mm, 200mm, 250mm, 300mm or 350mm, etc.

[0066] In some examples, L2 is greater than or equal to 20 mm and less than or equal to 80 mm. For example, the value of L2 can be 20 mm, 30 mm, 50 mm, 55 mm, 70 mm, or 80 mm, etc.

[0067] In some examples, the ratio of L1 to L2 is greater than or equal to 3 and less than or equal to 15. For example, the ratio of L1 to L2 can take values ​​of 3, 3.5, 6, 8, 9, 10, or 15. The units for both L1 and L2 are mm.

[0068] The cover plate assembly 100 also includes a pole post 20. The pole post 20 is larger in the second direction than in the first direction. The pole post 20 is fixed to the mounting hole 111 by a first flange 12 and a second flange 13. The pole post 20 covers at least a portion of the mounting hole 111.

[0069] The terminal 20 is used to electrically connect the battery cell 300 located inside the housing 200 to external devices (adjacent batteries or other electrical equipment) located outside the housing 200.

[0070] The battery can discharge to external devices through the tabs of cell 300 and terminals 20. An external power source can charge the battery through terminals 20 and the tabs of cell 300.

[0071] The pole 20 can be directly electrically connected to the tab of the battery cell 300, or it can be electrically connected to the tab of the battery cell 300 through a metal adapter.

[0072] The materials of the pole 20 include, but are not limited to, metals such as copper, aluminum, aluminum alloy, or copper-aluminum alloy.

[0073] There are two pole posts 20. The two pole posts 20 are installed in two mounting holes 111.

[0074] In some examples, one of the two terminals 20 is the positive terminal and the other is the negative terminal. The positive terminal 20 can be made of aluminum. The negative terminal 20 can be made of a copper-aluminum alloy.

[0075] The shape of the pole post 20 is not specifically set, as long as the dimension of the pole post 20 in the second direction is greater than the dimension of the pole post 20 in the first direction.

[0076] In some examples, the pole post 20 is racetrack shaped, with the two long sides of the pole post 20 on both sides in the first direction being straight, and the two short sides of the pole post 20 on both sides in the second direction being arc-shaped.

[0077] See Figure 6 As shown, the dimension of pole post 20 in the second direction is L3. The dimension of pole post 20 in the first direction is L4.

[0078] In some examples, L3 is greater than or equal to 15mm and less than or equal to 80mm. For example, the value of L3 can be 15mm, 20mm, 30mm, 50mm, 70mm, or 80mm, etc.

[0079] In some examples, L4 is greater than or equal to 10 mm and less than or equal to 50 mm. For example, the value of L4 can be 10 mm, 15 mm, 20 mm, 30 mm, 40 mm, or 50 mm, etc.

[0080] In some examples, the ratio of L3 to L4 is greater than or equal to 1.5 and less than or equal to 8. For example, the ratio of L3 to L4 can take values ​​of 1.5, 1.6, 2, 3, 5, 6, or 8. The units for both L3 and L4 are mm.

[0081] The cover plate assembly 100 also includes a seal 30. The seal 30 is at least partially disposed between the electrode post 20 and the cover plate 10. The seal 30 is used to seal between the electrode post 20 and the cover plate 10 to prevent electrolyte leakage from between the electrode post 20 and the cover plate 10.

[0082] The seal 30 can also serve as an insulator between the pole post 20 and the cover plate 10.

[0083] In some examples, the seal 30 may be made of an insulating, elastic material. For example, the material of the seal 30 includes, but is not limited to, silicone, fluororubber, soluble polytetrafluoroethylene, or polytetrafluoroethylene.

[0084] The area of ​​the end face of the pole post 20 on the side away from the cover plate body 11 in the third direction is S1.

[0085] S1 is greater than or equal to 30mm 2 and less than or equal to 450mm 2 The value of S1 can be 30mm. 2 50mm 2 100mm 2 200mm 2 300mm 2 400mm 2 Or 450mm 2 wait.

[0086] In the third direction, the overlapping area between the projection of the pole column 20 and the projection of the first flange 12 is S2.

[0087] S2 is greater than or equal to 15mm 2 and less than or equal to 400mm 2 The value of S2 can be 15mm. 2 50mm 2 100mm 2 200mm 2 300mm 2 350mm 2 Or 400mm 2 wait.

[0088] In the second direction, the pole post 20 includes a first portion 201 located between the two ends of the first flange 12 (see...). Figure 6 (As shown). The remaining part of pole 20 after removing the first part 201 is 202.

[0089] In the third direction, the area of ​​the portion of the seal 30 located between the cover body 11 and the first part 201 of the pole post 20 is S3.

[0090] In some examples, S3 is calculated as follows: The first flange 12 located in the +Y direction of the mounting hole 111 includes two endpoints located at both ends of the first flange 12 in the second direction. A cross-section of the cover assembly 100 is taken at the two endpoints, and the two cross-sections are perpendicular to the first flange 12. The distance between the two cross-sections is measured as D1 (see...). Figure 3b As shown), in the cross-section, the distance D2 between one end of the portion of the seal 30 located between the cover plate body 11 and the pole post 20 in the +Y direction and the inner wall of the mounting hole 111 is measured in the third direction (see Figure 1). Figure 4 As shown), the product of D1 and D2 is S31. The first flange 12 located in the -Y direction of the mounting hole 111 includes two endpoints, which are located at both ends of the first flange 12 in the second direction. A cross-section of the cover assembly 100 is taken at both endpoints, and the two cross-sections are perpendicular to the first flange 12. The distance between the two cross-sections is measured as D3. On the cross-section, in the third direction, the distance between one end of the portion of the seal 30 located between the cover body 11 and the pole post 20 in the -Y direction and the inner wall of the mounting hole 111 is measured as D4 (see...). Figure 4 As shown), the product of D3 and D4 is S32. The sum of S31 and S32 is S3. Where D1, D2, D3, and D4 are all in mm, and S31, S32, and S3 are all in mm. 2 .

[0091] D1 is greater than or equal to 15mm and less than or equal to 80mm. For example, the value of D1 can be 15mm, 20mm, 30mm, 40mm, 50mm, 60mm, 70mm or 80mm, etc.

[0092] D2 is greater than or equal to 0.5 mm and less than or equal to 2 mm. For example, the value of D2 can be 0.5 mm, 0.6 mm, 1 mm, 1.5 mm or 2 mm, etc.

[0093] D3 is greater than or equal to 15mm and less than or equal to 80mm. For example, the value of D3 can be 15mm, 20mm, 30mm, 40mm, 50mm, 60mm, 70mm or 80mm, etc.

[0094] D4 is greater than or equal to 0.5 mm and less than or equal to 2 mm. For example, the value of D4 can be 0.5 mm, 0.6 mm, 1 mm, 1.5 mm or 2 mm, etc.

[0095] S3 ≥ 30mm 2 and less than or equal to 300mm 2 The value of S3 can be 30mm. 2 50mm 2 100mm 2 150mm 2 200mm 2 250mm 2 Or 300mm 2 wait.

[0096] In the third direction, the overlapping area between the projection of the pole post 20 and the projection of the cover plate body 11 is S4.

[0097] S4 ≥ 50mm 2 and less than or equal to 1500mm 2 The value of S4 can be 50mm. 2 100mm 2 150mm 2 200mm 2 500mm 2 1000mm 2 Or 1500mm 2 wait.

[0098] S1, S2, S3, and S4 satisfy:

[0099] 0.01 ≤ (S2 / S1) × (S3 / S4) ≤ 0.3, where the units of S1, S2, S3, and S4 are all mm. 2 .

[0100] If (S2 / S1) × (S3 / S4) is less than 0.01, in the third direction, the overlapping area between the projection of the pole post 20 and the projection of the first flange 12 is too small, resulting in poor fixing effect of the first flange 12 on the pole post 20. This makes it easy for the cover plate 10 and the pole post 20 to fail to assemble, leading to sealing failure. If (S2 / S1) × (S3 / S4) is greater than 0.3, in the third direction, the overlapping area between the projection of the pole post 20 and the projection of the first flange 12 is too large, resulting in a reduced welding area between the pole post 20 and the busbar. This leads to poor heat dissipation of the pole post 20 and poor current carrying capacity of the pole post 20. By ensuring that (S2 / S1)×(S3 / S4) is greater than or equal to 0.01 and less than or equal to 0.3, the fixing effect of the first flange 12 on the pole post 20 can be improved, making it less likely for the cover plate 10 and the pole post 20 to fail during assembly. This ensures the sealing between the pole post 20 and the cover plate 10, and also increases the welding area between the pole post 20 and the busbar, thereby improving the heat dissipation performance and current carrying capacity of the pole post 20.

[0101] In one possible implementation, the ratio of S2 to S1 is greater than or equal to 0.05 and less than or equal to 0.5. If the ratio of S2 to S1 is less than 0.05, in the third direction, the overlapping area between the projection of the pole post 20 and the projection of the first flange 12 is too small, resulting in poor fixing effect of the first flange 12 on the pole post 20, making it easy for the cover plate 10 and the pole post 20 to fail to assemble, leading to sealing failure. If the ratio of S2 to S1 is greater than 0.5, in the third direction, the overlapping area between the projection of the pole post 20 and the projection of the first flange 12 is too large, resulting in a reduced welding area between the pole post 20 and the busbar, leading to poor current carrying capacity of the pole post 20. By ensuring that the ratio of S2 to S1 is greater than or equal to 0.05 and less than or equal to 0.5, the fixing effect of the first flange 12 on the pole post 20 can be improved, making it less likely for the cover plate 10 and the pole post 20 to fail during assembly. This ensures the sealing between the pole post 20 and the cover plate 10 and also increases the welding area between the pole post 20 and the busbar, thereby improving the current carrying capacity of the pole post 20.

[0102] The ratio of S3 to S4 is greater than or equal to 0.1 and less than or equal to 0.7. If the ratio of S3 to S4 is less than 0.1, in the third direction, the overlapping area between the projection of the portion of the seal 30 between the first flange 12 and the cover plate body 11 and the projection of the cover plate body 11 is too small, resulting in poor sealing between the first flange 12 and the cover plate body 11. If the ratio of S3 to S4 is greater than 0.7, in the third direction, the overlapping area between the projection of the portion of the seal 30 between the first flange 12 and the cover plate body 11 and the projection of the cover plate body 11 is too large, resulting in poor heat dissipation of the pole post 20 and poor current carrying capacity of the pole post 20. By ensuring that the ratio of S3 to S4 is greater than or equal to 0.1 and less than or equal to 0.7, the sealing performance between the first flange 12 and the cover plate body 11 can be improved, as can the heat dissipation performance of the pole post 20 and the current carrying capacity of the pole post 20.

[0103] In the first direction, the distance between the edge of the cover plate body 11 and the edge of the first flange 12 is L5. L5 is greater than or equal to 2 mm and less than or equal to 15 mm. For example, the value of L5 can be 2 mm, 2.5 mm, 3 mm, 5 mm, 8 mm, 10 mm, or 15 mm, etc. If L5 is less than 2 mm, the distance between the edge of the cover plate body 11 and the edge of the first flange 12 in the first direction will be too small, resulting in insufficient strength of the cover plate 10. If L5 is greater than 15 mm, the distance between the edge of the cover plate body 11 and the edge of the first flange 12 in the first direction will be too large, resulting in the electrode post being too small in the first direction, leading to poor current carrying capacity of the electrode post. By setting L5 to be greater than or equal to 2 mm and less than or equal to 15 mm, the strength of the cover plate 10 can be improved, and the current carrying capacity of the electrode post can also be improved.

[0104] In one possible implementation, see Figure 4 and Figure 5 As shown, the sealing element 30 includes a first sealing component 31 and a second sealing component 32. The first sealing component 31 is located between the pole post 20 and the cover plate body 11, and the second sealing component 32 is located between the first flange 12 and the pole post 20. This arrangement, with sealing components provided both between the pole post 20 and the cover plate body 11, and between the first flange 12 and the pole post 20, improves the sealing effect.

[0105] In some examples, the first seal 30 and the second seal 32 are integrated into one unit. This configuration improves the installation efficiency of the pole post 20.

[0106] In some examples, the first sealing component 31 and the second sealing component 32 are separate structures.

[0107] The thickness of the first sealing component 31 is greater than or equal to 1 mm and less than or equal to 1.3 mm. For example, the thickness of the first sealing component 31 can be 1 mm, 1.1 mm, 1.15 mm, 1.2 mm, 1.25 mm or 1.3 mm, etc.

[0108] The thickness of the second sealing component 32 is greater than or equal to 0.4 mm and less than or equal to 0.7 mm. For example, the thickness of the second sealing component 32 can be 0.4 mm, 0.45 mm, 0.5 mm, 0.6 mm, 0.65 mm or 0.7 mm, etc.

[0109] The thickness of the first sealing component 31 is greater than the thickness of the second sealing component 32, and the difference between the thickness of the first sealing component 31 and the thickness of the second sealing component 32 is greater than or equal to 0.3 mm and less than or equal to 0.8 mm. For example, the difference between the thickness of the first sealing component 31 and the thickness of the second sealing component 32 can be 0.3 mm, 0.35 mm, 0.4 mm, 0.5 mm, 0.75 mm, or 0.8 mm, etc.

[0110] In one possible implementation, see Figure 6 and Figure 7 As shown, the electrode post 20 includes an electrode post body 21 and a first protrusion 22, the first protrusion 22 being disposed on the side of the electrode post body 21 facing away from the battery cell 300 in a third direction.

[0111] The pole body 21 and the first protrusion 22 form a first step 221. The first flange 12 is fixed on the first step 221.

[0112] In some examples, along a third direction, the distance from the first flange 12 to the side of the first protrusion 22 away from the cover body 11 is H1 (see [reference]). Figure 4 As shown in the diagram, it can be understood that, along a third direction, the distance between the first flange 12 and the top of the pole post 20 is H1. H1 is greater than or equal to 0.3mm and less than or equal to 1.5mm. For example, the value of H1 can be 0.3mm, 0.5mm, 0.6mm, 0.8mm, 1mm, or 1.5mm, etc. This setting allows the first flange 12 to be spaced apart from the busbar, avoiding interference between the first flange 12 and the busbar and ensuring insulation between the first flange 12 and the busbar.

[0113] In some examples, the second flange 13 is fixed to the first step 221, and along the third direction, the distance between the second flange 13 and the side of the first protrusion 22 away from the cover plate body 11 is H2 (see Figure 5As shown in the diagram, it can be understood that, along a third direction, the distance between the second flange 13 and the top of the pole post 20 is H2. H2 is greater than or equal to 0.3 mm and less than or equal to 1.5 mm. For example, the value of H2 can be 0.3 mm, 0.5 mm, 0.6 mm, 0.8 mm, 1 mm, or 1.5 mm, etc. This setting allows the second flange 13 to be spaced apart from the busbar, avoiding interference between the second flange 13 and the busbar and ensuring insulation between the second flange 13 and the busbar.

[0114] In one possible implementation, see Figure 8 and Figure 9 As shown, the connection between the first flange 12 and the cover plate body 11 is the first connection point 121, and the connection between the second flange 13 and the cover plate body 11 is the second connection point 131. The first connection point 121 and the second connection point 131 are connected. This arrangement can improve the connection strength between the flange and the cover plate body 11. The connection between the first connection point 121 and the second connection point 131 allows the flange to be set around the entire circle, and the flange wraps around the pole post 20, which can improve the sealing effect.

[0115] A transition section 14 connects the first connection 121 and the second connection 131. It can be understood that the first connection 121 and the second connection 131 are connected by the transition section 14.

[0116] Along the third direction, the projection of the transition section 14 does not overlap with the projection of the pole post 20. This arrangement prevents stress concentration in the transition section 14 during the flanging process, which could lead to cracking.

[0117] In other embodiments, the connection between the first flange 12 and the cover plate body 11 is a first connection 121, and the connection between the second flange 13 and the cover plate body 11 is a second connection 131, with the first connection 121 and the second connection 131 spaced apart. This arrangement allows the first connection 121 and the second connection 131 to be disconnected. During the installation of the pole post 20, the first flange 12 and the second flange 13 can deform under the pressure of the pole post 20, preventing interference between the pole post 20 and the first flange 12 and the second flange 13. This facilitates the installation of the pole post 20 and improves the assembly efficiency of the cover plate assembly 100.

[0118] For example, the distance between the first connection 121 and the second connection 131 is greater than or equal to 1 mm and less than or equal to 5 mm. For instance, the distance between the first connection 121 and the second connection 131 can be 1 mm, 1.5 mm, 2 mm, 3 mm, 4 mm, or 5 mm, etc.

[0119] In one possible implementation, the thickness of the first flange 12 is greater than or equal to 0.6 mm and less than or equal to 1.5 mm. For example, the thickness of the first flange 12 can be 0.6 mm, 0.7 mm, 0.8 mm, 1 mm, 1.2 mm, or 1.5 mm, etc.

[0120] If the thickness of the first flange 12 is greater than 1.5mm, it becomes too thick and difficult to form. If the thickness of the first flange 12 is less than 0.6mm, it becomes too thin and results in poor fixation of the first flange 12 to the pole post 20. By limiting the thickness of the first flange 12, it can be made easier to form and the fixation effect of the first flange 12 on the pole post 20 can be improved.

[0121] The thickness of the second flange 13 is greater than or equal to 0.6 mm and less than or equal to 1.5 mm. For example, the thickness of the second flange 13 can be 0.6 mm, 0.7 mm, 0.8 mm, 1 mm, 1.2 mm or 1.5 mm, etc.

[0122] If the thickness of the second flange 13 is greater than 1.5mm, it becomes too thick and difficult to form. If the thickness of the second flange 13 is less than 0.6mm, it becomes too thin and results in poor fixation of the second flange 13 to the pole post 20. By limiting the thickness of the second flange 13, it can be made easier to form and the fixation effect of the second flange 13 on the pole post 20 can be improved.

[0123] In one possible implementation, the thickness of the first flange 12 on the side away from the cover plate body 11 is less than the thickness of the first flange 12 on the side closer to the cover plate body 11. This arrangement facilitates the stretching and shaping of the first flange 12, thereby facilitating the fixing of the pole post 20.

[0124] In one possible implementation, see Figures 10 to 12 As shown, the pole post 20 also includes a second protrusion 23, which is located on the side of the first protrusion 22 away from the cover plate body 11. The second protrusion 23 and the first protrusion 22 form a second step 231. The minimum distance L6 between the circumferential surface of the first protrusion 22 and the circumferential surface of the second protrusion 23 is greater than or equal to 0.3 mm and less than or equal to 3.5 mm. For example, the value of L6 can be 0.3 mm, 0.5 mm, 1 mm, 1.8 mm, 2 mm, 3 mm, or 3.5 mm, etc. This configuration increases the distance between the first flange 12 and the pole post 20 while ensuring the fixing strength of the first flange 12 to the pole post 20, thereby improving the insulation effect.

[0125] Figure 13 Cross section of the middle cover plate assembly and Figure 4 The cross-sections of the middle cover plate assembly are the same. Figure 14 Cross section of the middle cover plate assembly and Figure 5 The cross-sections of the middle cover plate assembly are the same.

[0126] In one possible implementation, see Figure 13 and Figure 14 As shown, the seal 30 partially extends into the mounting hole 111. The seal 30 has a first sidewall 301 located in the mounting hole 111 and facing the pole post 20. The distance between the first sidewall 301 and the inner wall of the mounting hole 111 is L7. L7 is greater than or equal to 0.5 mm and less than or equal to 3 mm. The value of L7 can be 0.5 mm, 0.8 mm, 1 mm, 2 mm, or 3 mm, etc. With this configuration, the sealing performance between the pole post 20 and the cover plate 10 can be improved by the seal 30 partially extending into the mounting hole 111.

[0127] The portion of the seal 30 that extends into the mounting hole 111 can be either bent or straight.

[0128] Figure 15 Cross section of the middle cover plate assembly and Figure 4 The cross-sections of the middle cover plate assembly are the same.

[0129] In other implementations, see Figure 15 As shown, the seal 30 is spaced apart from the inner wall of the mounting hole 111, and the distance between the seal 30 and the inner wall of the mounting hole 111 is L8. L8 is greater than or equal to 0.2 mm and less than or equal to 1.2 mm. The value of L8 can be 0.2 mm, 0.3 mm, 0.5 mm, 0.8 mm, 1 mm, or 1.2 mm, etc. This setting reduces the contact area between the electrolyte and the seal 30, slows down corrosion, and improves the sealing effect.

[0130] In one possible implementation, see Figure 13 and Figure 14 As shown, the first flange 12 and / or the second flange 13 include a vertical segment and a horizontal segment. Specifically, the first flange 12 includes a vertical segment and a horizontal segment. Alternatively, the second flange 13 includes a vertical segment and a horizontal segment. Alternatively, both the first flange 12 and the second flange 13 include a vertical segment and a horizontal segment.

[0131] The vertical section connects the horizontal section and the cover plate body, and the pole post 20 is fixed to the cover plate body through the horizontal section.

[0132] In some examples, both the first flange 12 and the second flange 13 include vertical segments and horizontal segments, that is, the first flange 12 includes a first vertical segment 1201 and a first horizontal segment 1202, and the second flange 13 includes a second vertical segment 1301 and a second horizontal segment 1302.

[0133] The first straight segment 1202 extends along the first direction. The second straight segment 1302 extends along the second direction.

[0134] The first vertical segment 1201 and the second vertical segment 1301 both extend in a third direction.

[0135] In the third direction, the dimensions of the vertical segment of the first flange 12 are the same as the dimensions of the vertical segment of the second flange 13, that is, in the third direction, the dimensions of the first vertical segment 1201 are the same as the dimensions of the second vertical segment 1301.

[0136] In the third direction, the dimension from the top of the cover plate body to the top of the first straight section 1202 is D5. That is, in the third direction, the dimension of the first vertical section 1201 is D5. D5 is greater than or equal to 1 mm and less than or equal to 3 mm. The value of D5 can be 1 mm, 1.1 mm, 1.5 mm, 2 mm, or 3 mm, etc.

[0137] If D5 is less than 1mm, the first flange 12 is too small in the third direction, causing the first straight section 1202 to not press against the pole post 20, and the first flange 12 cannot fix the pole post 20. If D5 is greater than 3mm, the first flange 12 is too large in the third direction, causing the first flange 12 to easily interfere with the busbar. By ensuring that D5 is greater than or equal to 1mm and less than or equal to 3mm, the first straight section 1202 can press against the pole post 20, the first flange 12 can fix the pole post 20, and interference with the busbar can be avoided.

[0138] In the first direction, the dimension of the portion of the first flange 12 covering the pole post 20 is D6, that is, in the first direction, the dimension of the first straight section 1202 is D6. D6 is greater than or equal to 1 mm and less than or equal to 3 mm. The value of D6 can be 1 mm, 1.1 mm, 1.5 mm, 2 mm, or 3 mm, etc.

[0139] If D6 is less than 1 mm, the size of the portion of the first flange 12 covering the pole post 20 in the first direction is too small, resulting in insufficient fixing strength of the first flange 12 to the pole post 20. If D6 is greater than 3 mm, the size of the portion of the first flange 12 covering the pole post 20 in the first direction is too large, and the size of the pole post 20 in the first direction is too small, resulting in poor current-carrying capacity of the pole post 20. By having D6 greater than or equal to 1 mm and less than or equal to 3 mm, the fixing strength of the first flange 12 to the pole post 20 can be improved, and the current-carrying capacity of the pole post 20 can also be improved.

[0140] In the second direction, the dimension of the portion of the second flange 13 covering the pole post 20 is D7, that is, in the second direction, the dimension of the second straight section 1302 is D7. D7 is greater than or equal to 0.8 mm and less than or equal to 2 mm. The value of D7 can be 0.8 mm, 1 mm, 1.1 mm, 1.5 mm or 2 mm, etc.

[0141] If D7 is less than 0.8 mm, the size of the portion of the second flange 13 covering the pole post 20 in the second direction is too small, resulting in insufficient fixing strength of the second flange 13 to the pole post 20. If D8 is greater than 2 mm, the size of the portion of the second flange 13 covering the pole post 20 in the second direction is too large, and the size of the pole post 20 in the second direction is too small, resulting in poor current-carrying capacity of the pole post 20. By ensuring that D7 is greater than or equal to 0.8 mm and less than or equal to 2 mm, the fixing strength of the second flange 13 to the pole post 20 can be improved, and the current-carrying capacity of the pole post 20 can also be improved.

[0142] Secondly, embodiments of this application provide a battery, including the cover assembly 100 of the first aspect.

[0143] The battery in this embodiment includes the cover plate assembly 100 in the aforementioned embodiments, which can improve the fixing effect of the first flange 12 on the terminal post 20, making it less likely for the cover plate 10 and the terminal post 20 to fail during assembly. This ensures the sealing between the terminal post 20 and the cover plate 10, and also increases the welding area between the terminal post 20 and the busbar, thereby improving the heat dissipation performance of the terminal post 20 and the current carrying capacity of the terminal post 20.

[0144] Thirdly, embodiments of this application provide a battery pack including a plurality of batteries as described in the second aspect.

[0145] The battery pack in this embodiment includes the battery in the aforementioned embodiment, which can improve the fixing effect of the first flange 12 on the terminal post 20, making it less likely for the cover plate 10 and the terminal post 20 to fail during assembly. This can ensure the sealing between the terminal post 20 and the cover plate 10, and can also increase the welding area between the terminal post 20 and the busbar, thereby improving the heat dissipation performance of the terminal post 20 and the current carrying capacity of the terminal post 20.

[0146] The battery provided in this application will be described in detail below through specific embodiments.

[0147] (1) Preparation of positive electrode sheet

[0148] The prepared positive electrode active material, conductive agent (e.g., acetylene black), and binder (e.g., PVDF) are mixed, and solvent NMP is added. The mixture is stirred under vacuum until the system is homogeneous to obtain a positive electrode slurry. The positive electrode slurry is uniformly coated on both surfaces of the positive electrode current collector aluminum foil, air-dried at room temperature, and then transferred to an oven for further drying. After cold pressing and slitting, the positive electrode sheet is obtained.

[0149] Specifically, the mass ratio of positive electrode active material: conductive agent: binder satisfies the following: (92~98): (4~1): (4~1).

[0150] (2) Preparation of negative electrode sheet

[0151] The negative electrode active material, conductive agent (e.g., acetylene black), thickener (e.g., CMC), and binder (e.g., SBR) are mixed, and deionized water is added as a solvent. The mixture is stirred under vacuum until the system is homogeneous to obtain a negative electrode slurry. The negative electrode slurry is uniformly coated on both surfaces of the negative electrode current collector copper foil, air-dried at room temperature, and then transferred to an oven for further drying. After cold pressing and slitting, the negative electrode sheet is obtained.

[0152] Specifically, the ratio of negative electrode active material: conductive agent: thickener: binder satisfies the following: (90~96): (4~2): (2~1): (4~1).

[0153] (3) Preparation of electrolyte:

[0154] Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of 1:1:1 to obtain an organic solvent. Then, fully dried lithium salt LiPF6 was dissolved in the mixed organic solvent to prepare an electrolyte with a concentration of 1 mol / L.

[0155] (4) Preparation of the separating membrane:

[0156] Polyethylene film was selected as the separator.

[0157] (5) Preparation of lithium-ion batteries:

[0158] The above-mentioned positive electrode sheet, separator, and negative electrode sheet are stacked in sequence, and then wound or stacked to obtain a bare cell. The bare cell is placed in an outer packaging shell, dried, injected with electrolyte, and then packaged, left to stand, formed, and calibrated to obtain a lithium-ion battery.

[0159] The positive electrode active material can be selected from one or more lithium-containing positive electrode active materials, including lithium iron phosphate, ternary materials containing nickel, cobalt and manganese, and lithium manganese iron phosphate.

[0160] The negative electrode active material can be selected from one or more of the following: artificial graphite, natural graphite, silicon carbide, silicon oxide, lithium titanate, etc.

[0161] If (S2 / S1)×(S3 / S4) is too small, the sealing between the cover plate and the pole will fail. The test method is as follows:

[0162] For each example and comparative example, corresponding cover plate assemblies are prepared according to the values in Table 1, 10 cover plate assemblies are prepared for each, and the cover plate assemblies are welded to the housing to form a battery housing. Except for the parameters in Table 1, the structures of the remaining batteries are all the same.

[0163] A through hole is opened on one surface of the battery housing. After evacuating the interior of the battery housing through the through hole, helium gas is injected into the battery housing until the internal pressure reaches 0.2 MPa, and the through hole opening is sealed. The air leakage at the pole area is tested with a battery helium leak detection mass spectrometer. After 5 seconds of testing, if the air leakage is ≤ 1×10 -6 Pa·m³ / s, it is qualified; otherwise, it is unqualified.

[0164] If (S2 / S1)×(S3 / S4) is too large, the pole is more prone to temperature rise. The test method is as follows:

[0165] For each example and comparative example, corresponding cover plate assemblies are prepared according to the values in Table 1, 10 cover plate assemblies are prepared for each, the battery cell is placed into the housing, and the cover plate assembly and the housing are welded to obtain batteries according to the above battery preparation method. Except for the parameters in Table 1, the structures of the remaining batteries are all the same; 10 batteries are connected in series through busbars to form a battery pack, and the busbars are welded to the poles of each battery.

[0166] Pole temperature rise test: Batteries are manufactured with the parameters in Table 1 below. Under the condition of 25°C, connect the pole 20 to a temperature sensor, discharge the battery at a rate of 1C until the battery voltage reaches the lower limit voltage, and then charge the battery at a rate of 5C until the battery voltage reaches the upper limit voltage. Measure the temperature of the poles of 10 batteries. If the maximum temperature T of the pole is less than or equal to 45°C, the test result is considered qualified; if the maximum temperature T of the pole is greater than 45°C, it is determined as unqualified.

[0167] It should be noted that for different battery systems, the upper and lower limit voltages need to be adjusted accordingly: the upper limit voltage of lithium iron phosphate (LFP) batteries is 3.65V, and the lower limit voltage is 2.5V; the upper limit voltage of lithium nickel cobalt manganese oxide (NCM) batteries is 4.25V, and the lower limit voltage is 2.5V; the upper limit voltage of lithium manganese iron phosphate (LFMP) batteries is 4.25V, and the lower limit voltage is 2.5V; the upper limit voltage of lithium nickel manganese oxide batteries is 4.8V, and the lower limit voltage is 3.5V.

[0168] This test example takes lithium iron phosphate battery as an example.

[0169] Table 1 Test parameters and results

[0170]

[0171] Compared to Comparative Example 2, when S1, S2, S3, and S4 satisfy the condition 0.01 ≤ (S2 / S1) × (S3 / S4), the leakage is less than 1 × 10⁻⁶. -6 The pressure is within Pa·m³ / s, and the leakage test is qualified. Limiting S1, S2, S3 and S4 can ensure the sealing between the cover plate and the pole.

[0172] Compared to Comparative Example 1, when S1, S2, S3 and S4 satisfy: (S2 / S1)×(S3 / S4)≤0.3, the temperature of the electrode is less than 45℃, which can ensure the heat dissipation performance of the electrode and the overcurrent capacity of the electrode.

[0173] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A cover plate assembly, characterized in that, include; A cover plate, the cover plate comprising a cover plate body, two first flanges and two second flanges, the cover plate body being provided with mounting holes, the two first flanges being disposed on opposite sides of the mounting holes in a first direction, and the two second flanges being disposed on opposite sides of the mounting holes in a second direction; The pole is fixed in the mounting hole by the first flange and the second flange, the pole covers at least part of the mounting hole, and the ratio of the size of the pole in the second direction to the size of the pole in the first direction is greater than or equal to 1.5 and less than or equal to 8. A sealing element is at least partially disposed between the pole and the cover plate; In the second direction, the pole post includes a first portion located between the two ends of the first flange; In the third direction, the area of ​​the end face of the pole away from the cover plate body is S1, the overlapping area of ​​the projection of the pole and the projection of the first flange is S2, the area of ​​the part of the sealing member located between the cover plate body and the first part of the pole is S3, and the overlapping area of ​​the projection of the pole and the projection of the cover plate body is S4. S1, S2, S3, and S4 satisfy the following: 0.01 ≤ (S2 / S1) × (S3 / S4) ≤ 0.3, where the units of S1, S2, S3, and S4 are all mm. 2 .

2. The cover plate assembly according to claim 1, characterized in that, The connection between the first flange and the cover plate body is the first connection point, and the connection between the second flange and the cover plate body is the second connection point. The first connection point and the second connection point are spaced apart. The distance between the first connection and the second connection is greater than or equal to 1 mm and less than or equal to 5 mm.

3. The cover plate assembly according to claim 1, characterized in that, The connection between the first flange and the cover plate body is the first connection point, and the connection between the second flange and the cover plate body is the second connection point. The first connection point and the second connection point are connected.

4. The cover plate assembly according to claim 3, characterized in that, A transition section connects the first connection point and the second connection point, and the projection of the transition section does not overlap with the projection of the pole post along the third direction.

5. The cover plate assembly according to claim 1, characterized in that, The thickness of the first flange is greater than or equal to 0.6 mm and less than or equal to 1.5 mm.

6. The cover plate assembly according to claim 1, characterized in that, The thickness of the first flange on the side away from the cover plate body is less than the thickness of the first flange on the side closer to the cover plate body.

7. The cover plate assembly according to claim 1, characterized in that, The pole post includes a pole post body and a first protrusion, the first protrusion being disposed on the pole post body on the third-direction side, and the pole post body and the first protrusion forming a first step; The first flange is fixed on the first step, and along the third direction, the distance between the first flange and the side of the first protrusion away from the cover plate body is greater than or equal to 0.3 mm and less than or equal to 1.5 mm; and / or, the second flange is fixed on the first step, and along the third direction, the distance between the second flange and the side of the first protrusion away from the cover plate body is greater than or equal to 0.3 mm and less than or equal to 1.5 mm.

8. The cover plate assembly according to claim 7, characterized in that, The pole post also includes a second protrusion, which is disposed on the side of the first protrusion away from the cover plate body. The second protrusion and the first protrusion form a second step. The minimum distance between the circumferential surface of the first protrusion and the circumferential surface of the second protrusion is greater than or equal to 0.3 mm and less than or equal to 3.5 mm.

9. The cover plate assembly according to claim 1, characterized in that, The sealing element is spaced apart from the inner wall of the mounting hole, and the distance between the sealing element and the inner wall of the mounting hole is greater than or equal to 0.2 mm and less than or equal to 1.2 mm.

10. The cover plate assembly according to claim 1, characterized in that, The sealing element extends into the mounting hole, and the sealing element has a first sidewall located in the mounting hole and facing the pole post. The distance between the first sidewall and the inner wall of the mounting hole is greater than or equal to 0.5 mm and less than or equal to 3 mm.

11. The cover plate assembly according to claim 1, characterized in that, The ratio of the dimension of the cover plate in the second direction to the dimension of the cover plate in the first direction is greater than or equal to 3 and less than or equal to 15.

12. The cover plate assembly according to any one of claims 1-11, characterized in that, In the first direction, the distance between the edge of the cover plate body and the edge of the first flange is greater than or equal to 2 mm and less than or equal to 15 mm.

13. The cover plate assembly according to any one of claims 1-11, characterized in that, The ratio of S2 to S1 is greater than or equal to 0.05 and less than or equal to 0.5, and the ratio of S3 to S4 is greater than or equal to 0.1 and less than or equal to 0.

7.

14. The cover plate assembly according to any one of claims 1-11, characterized in that, The first flange and / or the second flange includes a vertical section and a flat section, the vertical section being connected between the flat section and the cover plate body, and the pole being fixed to the cover plate body through the flat section.

15. The cover plate assembly according to claim 14, characterized in that, In the third direction, the vertical segment of the first flange has the same dimensions as the vertical segment of the second flange, and the vertical segment of the first flange has dimensions greater than or equal to 1 mm and less than or equal to 3 mm.

16. The cover plate assembly according to claim 14, characterized in that, In the first direction, the dimension of the straight section of the first flange is greater than or equal to 1 mm and less than or equal to 3 mm; and / or, in the second direction, the dimension of the straight section of the second flange is greater than or equal to 0.8 mm and less than or equal to 2 mm.

17. A battery, characterized in that, It includes a housing and a cover assembly as described in any one of claims 1-16; the cover assembly is connected to the housing.

18. A battery pack, characterized in that, Includes multiple batteries as described in claim 17.

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