Cover plate assembly, battery cell and battery module

Abstract

The utility model relates to battery technology field especially relates to a cover plate subassembly, electric core and battery module. The cover plate subassembly includes cover plate, riveting piece, compression ring and sealing element. Among them, the mounting hole is seted up on the cover plate, the riveting piece is worn in the mounting hole, and the compression ring and sealing element all are set up on the riveting piece, and the compression ring is located above the upper end surface of cover plate, and part sealing element is clamped between cover plate and compression ring. The arithmetic average roughness of compression ring lower end surface is Ra1, and the arithmetic average roughness of cover plate upper end surface is Ra2, and the absolute value of the difference of Ra1 and Ra2 does not exceed preset numerical value. The cover plate subassembly can avoid the phenomenon that the sealing element warps and the compression ring rises, improves the sealing property and reliability of electric core, prolongs the service life.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a cover plate assembly, a battery cell, and a battery module. Background Technology

[0002] Cylindrical lithium batteries are widely used due to their advantages such as high operating voltage, high energy density, and long cycle life. The cover plate assembly structure, as a key component of cylindrical lithium batteries, directly determines the battery's sealing, safety, and reliability. Through multi-layered protection and precise fit, the cover plate assembly ensures complete isolation between the battery's internal environment and the external environment, while simultaneously balancing internal pressure changes.

[0003] In the existing technology, the cover plate assembly may cause local warping of the sealing material (commonly known as "glue warping") during the riveting process, accompanied by local warping of the pressure ring, thereby reducing the sealing performance and reliability of the battery, leading to electrolyte evaporation, external moisture intrusion, and reduced battery cycle life.

[0004] Therefore, there is an urgent need to design a cover plate assembly, a battery cell, and a battery module to solve the above technical problems. Utility Model Content

[0005] The purpose of this invention is to provide a cover plate assembly, a battery cell, and a battery module that can prevent the sealing components from warping and the pressure ring from lifting, thereby improving the sealing performance and reliability of the battery cell and extending its service life.

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

[0007] On one hand, this utility model provides a cover plate assembly, which includes a cover plate, a riveting component, a pressure ring, and a sealing component; wherein, the cover plate has an installation hole, the riveting component passes through the installation hole, the pressure ring and the sealing component are both sleeved on the riveting component, the pressure ring is located above the upper end face of the cover plate, and part of the sealing component is sandwiched between the cover plate and the pressure ring;

[0008] The arithmetic mean roughness of the lower end face of the pressure ring is Ra1, and the arithmetic mean roughness of the upper end face of the cover plate is Ra2; the absolute value of the difference between Ra1 and Ra2 does not exceed a preset value.

[0009] As an optional technical solution for cover plate components, |Ra1-Ra2|≤4μm.

[0010] As an optional technical solution for the cover plate assembly, both Ra1 and Ra2 are set to be between 0.05μm and 5μm.

[0011] As an optional technical solution for the cover plate assembly, the outer peripheral side of the riveting member is provided with a riveting groove, and the pressure ring is riveted into the riveting groove.

[0012] As an optional technical solution for a cover plate assembly, the sealing element includes a first sealing part, a connecting part, and a second sealing part. One end of the connecting part is connected to the first sealing part, and the other end is connected to the second sealing part. The first sealing part is disposed on the upper end face of the cover plate, and the second sealing part is disposed on the lower end face of the cover plate. The connecting part is disposed in the mounting hole and is sleeved on the riveting member.

[0013] As an alternative technical solution for the cover plate assembly, the end of the second sealing portion extends outward along the radial direction of the riveting member to form an extension portion, the extension portion covering the electrode welding area.

[0014] As an optional technical solution for the cover plate assembly, the extension is arc-shaped and bends away from the cover plate to form an arc-shaped isolation barrier to prevent the tab from contacting the cover plate.

[0015] As an optional technical solution for the cover plate assembly, the length of the second sealing part is set to D1 along the radial direction of the riveting member, and the length of the cover plate is set to D2, where 1 / 3≤D1 / D2≤5 / 6.

[0016] On the other hand, the present invention provides a battery cell, the battery cell including a housing, an electrode group and a cover plate assembly as described in any of the above optional technical solutions, the electrode group being disposed inside the housing, and the cover plate assembly covering the open end of the housing to seal the housing; the electrode group including electrode tabs, the electrode tabs being connected to the riveting member.

[0017] In another aspect, this utility model provides a battery module, which includes conductive connectors and multiple or more of the aforementioned battery cells. The conductive connectors are connected in series and / or in parallel with the multiple battery cells, and the cover plate assemblies of the battery cells are arranged in the same direction.

[0018] The beneficial effects of this utility model include at least the following:

[0019] This utility model provides a cover plate assembly, which includes a cover plate, a riveting component, a pressure ring, and a sealing component. The cover plate has mounting holes, through which the riveting component passes. The pressure ring and the sealing component are both fitted onto the riveting component. The pressure ring is located above the upper end face of the cover plate, and part of the sealing component is sandwiched between the cover plate and the pressure ring. The arithmetic mean roughness of the lower end face of the pressure ring is Ra1, and the arithmetic mean roughness of the upper end face of the cover plate is Ra2; the absolute value of the difference between Ra1 and Ra2 does not exceed a preset value.

[0020] By controlling the difference in arithmetic mean roughness between the lower end face of the pressure ring and the upper end face of the cover plate, the stress condition of the seal during riveting can be effectively improved, making the friction force on the upper and lower surfaces of the seal more balanced. When the difference in arithmetic mean roughness between the two does not exceed a preset value, the seal is subjected to uniform stress during riveting, avoiding local stress concentration caused by excessive arithmetic mean roughness differences. At the same time, the pressure ring is subjected to balanced stress, reducing warping caused by excessive stress on one side, thereby reducing warping of the seal or local deformation of the pressure ring. This results in a tighter fit between the seal and the cover plate and pressure ring, reducing the risk of electrolyte evaporation and moisture intrusion, significantly improving the sealing performance and reliability of the battery cell, and extending its service life.

[0021] This utility model provides a battery cell with high sealing performance and reliability, which can prevent the sealing components from warping and the pressure ring from lifting, prevent electrolyte leakage and external moisture intrusion, and extend service life.

[0022] This utility model provides a battery module with high reliability and sealing performance, which can extend the service life of the battery module. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of this utility model and these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the cover plate assembly and electrode lug provided in this embodiment of the utility model;

[0025] Figure 2 This is a schematic diagram of the structure of the cover plate assembly (Ra1-Ra2≥4μm) provided in this embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the structure of the cover plate assembly (Ra2-Ra1≥4μm) provided in this embodiment of the present invention.

[0027] Figure Labels

[0028] 100. Cover plate assembly; 200. Electrode tab;

[0029] 10. Cover plate; 11. Mounting hole; 20. Riveting component; 21. Riveting groove; 30. Pressure ring; 40. Seal; 41. First sealing part; 42. Connecting part; 43. Second sealing part; 44. Extension part. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0031] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0032] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0033] In the description of this utility model, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this utility model is in use. They are used only for the convenience of describing this utility model and for simplifying the description, 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 this utility model. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0034] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0035] 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.

[0036] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0037] This embodiment provides a cover plate assembly that can prevent the sealing element from warping and the pressure ring from lifting, thereby improving the sealing performance and reliability of the battery cell and extending its service life.

[0038] like Figures 1-3 As shown, the cover plate assembly 100 mainly includes a cover plate 10, a riveting member 20, a pressure ring 30, and a sealing member 40. The cover plate 10 has a mounting hole 11, through which the riveting member 20 passes. The pressure ring 30 and the sealing member 40 are both fitted onto the riveting member 20. The pressure ring 30 is located above the upper end face of the cover plate 10, and part of the sealing member 40 is sandwiched between the cover plate 10 and the pressure ring 30. The arithmetic mean roughness of the lower end face of the pressure ring 30 is Ra1, and the arithmetic mean roughness of the upper end face of the cover plate 10 is Ra2; the absolute value of the difference between Ra1 and Ra2 does not exceed a preset value.

[0039] Based on the above design, in this embodiment, by controlling the difference in the arithmetic mean roughness between the lower end face of the pressure ring 30 and the upper end face of the cover plate 10, the stress condition of the seal 40 during the riveting process can be effectively improved, making the friction force on the upper and lower surfaces of the seal 40 more balanced. When the difference in the arithmetic mean roughness between the two does not exceed a preset value, the seal 40 is subjected to uniform force during the riveting process, avoiding the phenomenon of local stress concentration in the seal 40 caused by excessive difference in arithmetic mean roughness. At the same time, the pressure ring 30 is subjected to balanced force, reducing the warping phenomenon caused by excessive stress on one side, thereby reducing the warping of the seal 40 or the local deformation of the pressure ring 30, and thus making the seal 40 fit more tightly with the cover plate 10 and the pressure ring 30, reducing the risk of electrolyte evaporation and moisture intrusion, significantly improving the sealing performance and reliability of the battery cell, and extending its service life.

[0040] It should be noted that the arithmetic mean roughness (Ra1 and Ra2) in this embodiment are parameters used to characterize the micro-unevenness of the lower end face of the pressure ring 30 and the upper end face of the cover plate 10. It is defined as: the arithmetic mean of the absolute values ​​of the distances from each point on the measured surface profile to the profile centerline (e.g., the average line) within the sampling length. For ease of description, roughness is used instead of arithmetic mean roughness in the following text.

[0041] In some optional embodiments, |Ra1-Ra2|≤4μm, that is, the preset value is set to 4μm. This helps to control the flow and stress distribution of the seal 40 more precisely, ensuring that the seal 40 can be uniformly filled during the riveting process, enhancing the sealing effect, while avoiding damage to the seal 40 due to excessive roughness differences, and extending the service life of the cover plate assembly 100.

[0042] like Figure 2 As shown, if Ra1-Ra2≥4μm, the roughness of the lower end face of the pressure ring 30 is much greater than the roughness of the upper end face of the cover plate 10. The lower end face (Ra1) of the pressure ring 30 is rougher, and the friction between the lower end face of the pressure ring 30 and the upper surface of the seal 40 is much greater than the friction between the upper end face (Ra2) of the cover plate 10 and the lower surface of the seal 40. During the riveting process of the riveting component 20, the upper surface of the seal 40 experiences flow obstruction due to high friction, while the lower surface experiences easier flow due to low friction. This results in the asymmetrical accumulation of the seal 40 material towards one side of the cover plate 10, forming a "lifting" phenomenon, such as... Figure 2 As shown in the dashed circle at point A in the middle.

[0043] like Figure 3 As shown, if Ra2-Ra1≥4μm, the roughness of the upper surface of the cover plate 10 is much greater than that of the lower surface of the pressure ring 30. The upper surface (Ra2) of the cover plate 10 is rougher, and the friction between the upper surface of the cover plate 10 and the lower surface of the seal 40 is much greater than the friction between the lower surface (Ra1) of the pressure ring 30 and the upper surface of the seal 40. During riveting of the riveting component 20, the flow on the lower surface of the seal 40 is obstructed, while the upper surface flows more easily due to lower friction. This causes the seal 40 to accumulate towards the pressure ring 30, forming a reverse lifting phenomenon, which can easily lead to localized lifting of the pressure ring 30, such as... Figure 3 As shown in the dashed circle at point B.

[0044] Therefore, setting |Ra1-Ra2|≤4μm can better control the flow and stress distribution of the seal 40, improve the stress condition of the seal 40, avoid the phenomenon of asymmetric accumulation of the seal 40 material, and thus avoid the phenomenon of seal 40 peeling and pressure ring 30 lifting.

[0045] In some optional embodiments, Ra1 and Ra2 are both set between 0.05 μm and 5 μm. This avoids the lower end face of the pressure ring 30 and the upper end face of the cover plate 10 being too rough (>5 μm), which could cause the seal 40 to be scratched by sharp protrusions, thus extending the life of the seal 40. At the same time, it avoids the lower end face of the pressure ring 30 and the upper end face of the cover plate 10 being too smooth (e.g., <0.05 μm), which would lead to a surge in the processing cost of ultra-fine polishing. By retaining a moderate roughness to enhance the friction between the seal 40 and the contact surface, the seal 40 is prevented from slipping in a vibrating environment.

[0046] Preferably, in this embodiment, both Ra1 and Ra2 are set to 1.2 μm.

[0047] In some alternative embodiments, the material of the riveting member 20 is selected from aluminum alloy or steel alloy. The materials of the cover plate 10 and the pressure ring 30 are both selected from stainless steel. The material of the sealing member 40 is selected from PFA, PBT or PP, and it is integrally formed with the cover plate 10 by injection molding.

[0048] like Figure 1 As shown, a riveting groove 21 is provided on the outer periphery of the riveting component 20, and the pressure ring 30 is riveted into the riveting groove 21. Through the interlocking structure of the riveting groove 21 and the pressure ring 30, the pressure ring 30 and the riveting component 20 are mechanically locked together, thereby improving the fixing strength. After riveting, the edge of the pressure ring 30 is embedded in the riveting groove 21 and cannot move axially, ensuring that the sealing component 40 is always subjected to a stable clamping force and avoiding the problem of local sealing failure caused by the loosening of the pressure ring 30.

[0049] like Figure 1 As shown, the sealing element 40 in this embodiment includes a first sealing part 41, a connecting part 42, and a second sealing part 43. One end of the connecting part 42 is connected to the first sealing part 41, and the other end is connected to the second sealing part 43. The first sealing part 41 is disposed on the upper end surface of the cover plate 10, and the second sealing part 43 is disposed on the lower end surface of the cover plate 10. The connecting part 42 is disposed in the mounting hole 11 and is sleeved on the riveting element 20.

[0050] The first sealing part 41 can block the axial gap between the cover plate 10 and the pressure ring 30, the connecting part 42 fills the radial gap between the mounting hole 11 and the riveting part 20 to prevent the electrolyte from seeping out from the hole wall of the mounting hole 11, and the second sealing part 43 covers the lower end face of the cover plate 10 to prevent the internal electrolyte from spreading to the edge of the cover plate 10.

[0051] Optionally, the thickness of the first sealing part 41, the second sealing part 43 and the connecting part 42 are all set to 0.3mm-0.5mm, and the connecting part 42 is interference-fitted with the mounting hole 11 with an interference amount of 0.02mm-0.05mm.

[0052] like Figure 1As shown, the end of the second sealing part 43 extends outward along the radial direction of the riveting member 20 to form an extension part 44. The extension part 44 covers the welding area of ​​the tab 200, which effectively isolates the tab 200 from direct contact with the cover plate 10, avoiding the risk of short circuit caused by the tab 200 crossing the boundary. At the same time, it enhances the sealing performance of the welding area of ​​the tab 200, preventing electrolyte leakage and external moisture intrusion, and improving the safety and reliability of the battery cell. In addition, the extension part 44 can also buffer the thermal stress during the welding of the tab 200, reducing the aging phenomenon of the sealing member 40 caused by local high temperature.

[0053] Furthermore, the extension 44 is arc-shaped and bends away from the cover plate 10 to form an arc-shaped isolation barrier to prevent the tab 200 from contacting the cover plate 10.

[0054] The arc-shaped extension 44 provides elastic cushioning. Specifically, when the tab 200 deforms, the arc-shaped extension 44 absorbs stress through its own bending, preventing it from being lifted up. Furthermore, the arc-shaped extension 44 bends away from the cover plate 10, increasing the gap with the cover plate 10 and further reducing the probability of the tab 200 penetrating the extension 44 and contacting the cover plate 10. In contrast, when the tab 200 is subjected to bending deformation due to vibration or temperature changes, the planar extension is easily lifted up by the tab 200 and contacts the cover plate 10. In addition, the arc-shaped extension 44 better guides the end of the tab 200 away from the surface of the cover plate 10, increasing the electrical clearance between the tab 200 and the cover plate 10 and effectively reducing the risk of short circuits. Under stress, the arc-shaped extension 44 can evenly distribute stress, reducing damage to the seal 40 caused by localized stress concentration, further improving the structural stability and sealing performance of the cover plate assembly 100.

[0055] For example, the bending height of the arc-shaped extension 44 can be set to 0.2mm-0.3mm, the bending angle to 15°-30°, and the minimum gap between the extension and the cover plate 10 after bending is ≥0.2mm.

[0056] like Figure 1As shown, along the radial direction of the riveting member 20, the length of the second sealing part 43 is set to D1, and the length of the cover plate 10 is set to D2, where 1 / 3 ≤ D1 / D2 ≤ 5 / 6. If D1 / D2 < 1 / 3, the coverage area of ​​the second sealing part 43 is too small, which cannot effectively isolate the tab 200 from the cover plate 10, and the insufficient sealing area can easily lead to electrolyte leakage. If D1 / D2 > 5 / 6, the second sealing part 43 is close to the edge of the cover plate 10, which may interfere with the battery cell housing, affecting the sealing assembly of the cover plate assembly 100 and the housing. Therefore, setting the ratio range of 1 / 3 ≤ D1 / D2 ≤ 5 / 6 can ensure that the second sealing part 43 covers the welding area of ​​the tab 200 without affecting the assembly of the cover plate assembly 100 and the housing due to excessive size, achieving an optimized balance between sealing performance and space utilization, and improving the overall performance and reliability of the cover plate assembly 100.

[0057] Preferably, 1 / 2 ≤ D1 / D2 ≤ 2 / 3; more preferably, D1 / D2 = 2 / 3.

[0058] This embodiment also provides a battery cell, which includes a housing, an electrode assembly and the aforementioned cover plate assembly 100. The electrode assembly is disposed inside the housing, and the cover plate assembly 100 covers the open end of the housing to seal the housing. The electrode assembly includes electrode tabs 200, which are connected to the riveting member 20.

[0059] Because the battery cell has the aforementioned cover plate assembly 100, it has high sealing performance and reliability, which can prevent the sealing element 40 from warping and the pressure ring 30 from lifting, prevent electrolyte leakage and external moisture intrusion, and extend service life.

[0060] For example, the housing and cover plate 10 are connected by laser welding to ensure the sealing performance of the housing and cover plate 10. The tab 200 and the riveting part 20 are ultrasonically welded to avoid poor contact caused by incomplete welding.

[0061] Even after high-temperature testing, the battery cell still maintains good sealing and safety, preventing electrolyte leakage and evaporation, and preventing external moisture from entering the battery cell.

[0062] This embodiment designs the following experimental verification based on the performance of the battery cell after high-temperature shock, and the comparison results are as follows:

[0063] Table 1: Comparison of Parameters between This Example and the Comparative Example

[0064] This embodiment 1.3-1.4 1.2-1.3 2 / 3 Comparative Example 1 1.3-1.4 1.2-1.3 1 / 7 Comparative Example 2 0.8-0.9 0.9-1.0 5 / 6 Comparative Example 3 2.1-2.2 2.0-2.1 1 / 3 Comparative Example 4 0.8-0.9 5.1-5.2 5 / 6 Comparative Example 5 5.3-5.4 0.8-0.9 1 / 3

[0065] Table 2: Comparison of Results Between This Example and the Comparative Example

[0066]

[0067] The examples and comparative results described above demonstrate that the battery cell in this embodiment can reduce the risk of electrolyte leakage, thereby improving the cell's sealing performance and reliability. Furthermore, it can effectively prevent internal contact problems caused by deformation of the cover assembly 100 due to thermal expansion of the seal 40 in high-temperature environments, thus extending the battery cell's service life.

[0068] This embodiment also provides a battery module, which includes conductive connectors and multiple battery cells. The conductive connectors are connected in series and / or in parallel with the multiple battery cells, and the cover plate assembly 100 of the battery cells is arranged in the same direction. This facilitates the uniform connection of the conductive connectors without distinguishing the direction, and reduces assembly errors.

[0069] For example, the conductive connector can be configured as a busbar, which connects the riveting part 20 (positive electrode) of adjacent cells to the housing (negative electrode) when connected in series, and connects all riveting parts 20 through the positive electrode busbar and all housings through the negative electrode busbar when connected in parallel.

[0070] Because the battery module has the aforementioned cells, it has high reliability and sealing performance, which can extend the battery module's service life.

[0071] Obviously, the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

[0072] Note that in the description of this specification, the references to terms such as "some embodiments," "other embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this utility model. 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.

Claims

1. A cover plate assembly, characterized in that, The cover plate assembly (100) includes a cover plate (10), a riveting member (20), a pressure ring (30), and a sealing member (40); The cover plate (10) has an installation hole (11), the rivet (20) passes through the installation hole (11), the pressure ring (30) and the sealing element (40) are both sleeved on the rivet (20), the pressure ring (30) is located above the upper end face of the cover plate (10), and part of the sealing element (40) is sandwiched between the cover plate (10) and the pressure ring (30); The arithmetic mean roughness of the lower end face of the pressure ring (30) is Ra1, and the arithmetic mean roughness of the upper end face of the cover plate (10) is Ra2; the absolute value of the difference between Ra1 and Ra2 does not exceed a preset value.

2. The cover plate assembly according to claim 1, characterized in that, |Ra1-Ra2|≤4μm.

3. The cover plate assembly according to claim 2, characterized in that, Both Ra1 and Ra2 are set to be between 0.05μm and 5μm.

4. The cover plate assembly according to claim 1, characterized in that, The outer periphery of the rivet (20) is provided with a rivet groove (21), and the pressure ring (30) is riveted into the rivet groove (21).

5. The cover plate assembly according to claim 1, characterized in that, The sealing element (40) includes a first sealing part (41), a connecting part (42), and a second sealing part (43). One end of the connecting part (42) is connected to the first sealing part (41), and the other end is connected to the second sealing part (43). The first sealing part (41) is disposed on the upper end face of the cover plate (10), and the second sealing part (43) is disposed on the lower end face of the cover plate (10). The connecting part (42) is disposed in the mounting hole (11), and the connecting part (42) is sleeved on the riveting element (20).

6. The cover plate assembly according to claim 5, characterized in that, The end of the second sealing part (43) extends outward along the radial direction of the riveting member (20) to form an extension (44), which covers the welding area of ​​the tab (200).

7. The cover plate assembly according to claim 6, characterized in that, The extension (44) is arc-shaped and bends away from the cover plate (10) to form an arc-shaped isolation barrier to prevent the tab (200) from contacting the cover plate (10).

8. The cover plate assembly according to claim 5, characterized in that, Along the radial direction of the riveting member (20), the length of the second sealing part (43) is set to D1, and the length of the cover plate (10) is set to D2, 1 / 3≤D1 / D2≤5 / 6.

9. A battery cell, characterized in that, The battery cell includes a housing, an electrode assembly, and a cover plate assembly (100) according to any one of claims 1-8. The electrode assembly is disposed inside the housing, and the cover plate assembly (100) covers the open end of the housing to seal the housing. The electrode assembly includes a tab (200) connected to the riveting member (20).

10. A battery module, characterized in that, The battery module includes conductive connectors and multiple battery cells as described in claim 9, wherein the conductive connectors are connected in series and / or in parallel with multiple battery cells, and the cover plate assemblies (100) of the battery cells are arranged in the same direction.

Images