End cover assembly, battery cell, and energy storage device

Abstract

To improve the safety of battery cells. [Solution] The end cover assembly includes a top cover, an upper plastic material, a pole column, and a support portion. The top cover has first and second surfaces facing each other along the thickness direction, and through holes penetrating the first and second surfaces, respectively. The upper plastic material is installed on the first surface side of the top cover and has through holes and mounting holes that are spaced apart and partially drilled in the through holes, and has a first orthographic projection on the first surface. The pole column includes a flange portion and a drilled portion. The flange portion is located on one side away from the top cover and in contact with the upper plastic material, and has a second orthographic projection on the first surface. The drilled portion is convex on one side of the flange portion toward the first surface and is drilled in the through hole. The support portion is drilled in the mounting hole and is located between the flange portion and the top cover, and has a third orthographic projection on the first surface that partially overlaps the first and second orthographic projections.

Description

Technical Field

[0001] This application relates to the technical field of energy storage, specifically to an end cover assembly, a battery cell, and an energy storage device.

Background Art

[0002] For the end cover assembly of a battery cell, it is necessary to adopt an upper plastic material so that the pole post and the pressing ring are respectively installed insulated from the top cover. Also, it is necessary to install a sealing ring between the top cover and the pole post. Through the cooperation of the upper plastic material, the pole post, the pressing ring, and the top cover, etc., the sealing ring is compressed to prevent the occurrence of liquid leakage (i.e., leakage of the electrolyte) in the battery cell. However, the upper plastic material is a resin material. When thermal runaway occurs in the battery cell, the temperature of the battery cell rises, which makes the upper plastic material prone to melting and the pole post prone to sinking into the upper plastic material. As a result, the compression amount of the sealing ring decreases, making the battery cell prone to electrolyte leakage and reducing the safety of the battery cell.

Summary of the Invention

[0003] The first aspect of this application provides an end cover assembly. The end cover assembly includes a top cover, an upper plastic material, a pole post, and a support portion. The top cover has a first surface and a second surface that are oppositely installed along its thickness direction. The top cover further has a through hole. The through hole penetrates the first surface and the second surface respectively. The upper plastic material is installed on the first surface side of the top cover and is partially drilled into the through hole. The upper plastic material has through holes and mounting holes installed at intervals. The upper plastic material has a first orthographic projection on the first surface. The pole column includes a connecting flange portion and a perforated portion. The flange portion is located on one side away from the top cover of the upper plastic material and abuts against the upper plastic material. The perforated portion is convex on one side toward the first surface of the flange portion and is perforated in a through hole. The flange portion has a second orthographic projection on the first surface. The support portion is drilled into the mounting hole. Along the alignment direction of the first surface and the second surface, the support portion is located between the flange portion and the top cover. The support portion has a third orthographic projection on the first surface. The third orthographic projection partially overlaps with the first orthographic projection and partially overlaps with the second orthographic projection.

[0004] A second aspect of this application provides a battery cell, which includes a housing, an end cover assembly as described in the embodiment of this application, and an electrode assembly. The end cover assembly and housing surround each other to form a housing cavity. The electrode assembly is installed in the housing cavity and electrically connected to the electrode poles of the end cover assembly.

[0005] A third aspect of this application provides an energy storage device, which includes a housing and a plurality of battery cells described in the embodiments of this application. The enclosure has a storage cavity. Multiple battery cells are housed in a containment cavity.

[0006] An end cover assembly according to an embodiment of this application includes a top cover, an upper plastic material, poles, and a support. The top cover further has through holes. The upper plastic material is positioned on the first surface side of the top cover and is partially drilled into the through holes. The upper plastic material has spaced through holes and mounting holes. The poles include a connecting flange portion and a drilled portion. The flange portion is located on one side of the upper plastic material away from the top cover and abuts against the upper plastic material. The drilled portion is convex on one side of the flange portion toward the first surface and is drilled into the through holes. The support is drilled into the mounting holes. In this embodiment, when thermal runaway occurs in the battery cell or when assembling the end cover assembly, the temperature of the poles rises, causing the upper plastic material to melt, releasing the repulsive force of the seal ring, and the poles to sink (i.e., the flange portion moves toward the top cover). By installing a support portion within the upper plastic material, after the pole column sinks to a certain distance, the support portion contacts and supports the flange portion, thereby preventing the pole column from continuing to sink and preventing the release of all the repulsive force from the seal ring. As a result, leakage of electrolyte from the battery cell can be better avoided, and the safety of using the battery cell can be improved. Furthermore, the upper plastic material according to the embodiment of this application has a first orthographic projection on its first surface. The flange portion has a second orthographic projection on its first surface. The support portion has a third orthographic projection on its first surface. The third orthographic projection partially overlaps with the first orthographic projection and partially overlaps with the second orthographic projection. Because the third orthographic projection partially overlaps with the second orthographic projection, the support portion can properly support the flange portion when the temperature inside the battery cell rises. Furthermore, the partial overlap of the third orthographic projection with the first orthographic projection means that the support portion can be attached to the upper plastic material and the support portion can be supported by the overlapping portion between the upper plastic material and the support portion. This better prevents the support from detaching from the upper plastic material when the support / upper plastic material assembly is transferred to the next station, improving the assembly yield of the upper plastic material and support, and consequently improving the safety of the battery cells. [Brief explanation of the drawing]

[0007] Below, in order to more clearly explain the technical proposal according to the embodiments of this application, the necessary drawings for the embodiments are briefly introduced. Clearly, the drawings described are some embodiments of this application, and those skilled in the art can obtain other drawings from these without any creative effort. [Figure 1] Figure 1 is a schematic diagram showing the structure of an energy storage device according to one embodiment of this application. [Figure 2] Figure 2 is a schematic diagram showing the structure of a battery cell according to one embodiment of this application. [Figure 3] Figure 3 is a cross-sectional view showing the structure of a battery cell according to one embodiment of this application, along the A-A direction in Figure 2. [Figure 4] Figure 4 is a schematic diagram showing the structure of an end cover assembly according to one embodiment of this application. [Figure 5] Figure 5 is an exploded view showing the structure of an end cover assembly according to one embodiment of this application. [Figure 6] Figure 6 is an exploded view showing the structure of an end cover assembly from a different angle according to one embodiment of this application. [Figure 7] Figure 7 is a schematic diagram showing the structure of a pole column according to one embodiment of this application. [Figure 8] Figure 8 is a plan view showing the structure of an end cover assembly according to one embodiment of this application. [Figure 9] Figure 9 is a cross-sectional view showing the structure of an end cover assembly according to one embodiment of this application, along the B-B direction in Figure 8. [Figure 10] Figure 10 is an enlarged view of the dashed frame I in Figure 9. [Figure 11] Figure 11 is a cross-sectional view showing the structure after assembly of the upper plastic material, pole column, and support part according to one embodiment of this application. [Figure 12] Figure 12 is a plan perspective view showing the structure after assembling the upper plastic material and support part according to one embodiment of this application. [Figure 13] Figure 13 is a cross-sectional view showing the structure after assembly of the upper plastic material, pole column, and support part according to another embodiment of this application. [Figure 14] Figure 14 is a partially cross-sectional view showing the structure after the upper plastic material, pole column, support part, and top cover have been assembled according to one embodiment of this application. [Figure 15] Figure 15 is a partially cross-sectional view showing the structure after the upper plastic material, pole column, support section, and top cover have been assembled according to another embodiment of this application. [Modes for carrying out the invention]

[0008] To enable those skilled in the art to better understand the technical concept of this application, the technical concept of the embodiments of this application will be described clearly and comprehensively below with reference to the drawings of the embodiments of this application. Clearly, the embodiments described are only some, and not all, embodiments of this application. All other embodiments that a person skilled in the art can obtain without creative effort based on the embodiments of this application are all within the scope of protection of this application.

[0009] In the specification, claims, and drawings of this application, terms such as “first,” “second,” etc., are used not to describe a specific sequence, but to distinguish different subjects. Furthermore, terms such as “includes,” “has,” or any other variant are intended to cover, without excluding, other components. For example, a process, method, system, product, or device comprising a series of steps or units may, but is not limited to, further include other steps or units not listed, or may, selectively, further include other steps or units specific to those processes, methods, systems, products, or devices.

[0010] The technical proposal of the embodiment of this application will be described below with reference to the drawings.

[0011] For the sake of convenience of explanation, in the embodiments of the present application, the same reference numerals denote the same members, and for the sake of brevity, in different embodiments, the detailed description of the same members is omitted.

[0012] Currently, the production of green power generally depends on solar power generation, wind power generation, hydroelectric power generation, etc. However, wind energy and solar energy are highly intermittent and unstable. As a result, the power grid becomes unstable, the power supply is insufficient at the peak of power consumption, and the power supply is excessive at the trough of power consumption. In addition, unstable voltage further damages the power. Therefore, due to insufficient power consumption needs or insufficient grid capacity, the problem of "abandoning wind and light" may be caused. It is necessary to rely on energy storage to solve these problems. That is, electrical energy is converted into other forms of energy and stored by physical or chemical methods, and the energy is converted into electrical energy and released when needed. Simply put, energy storage is similar to a large "mobile battery", that is, when solar energy and wind energy are sufficient, these energies are converted into electrical energy and stored, and the stored electrical energy is released when needed.

[0013] Taking electrochemical energy storage as an example. The present application provides an energy storage device. An electrochemical cell is provided in the energy storage device. In the energy storage device, mainly the chemical elements in the electrochemical cell are used as the energy storage medium. In the charge-discharge process, there is a chemical reaction or change in the energy storage medium. Simply put, the electrical energy generated by wind energy and solar energy is stored in the electrochemical cell. When the use of external electrical energy reaches the peak, the stored electrical energy is released and used, or transferred to a place where electrical energy is insufficient and used.

[0014] Refer to FIG. 1. Embodiments of the present application provide an energy storage device 300. The energy storage device 300 includes a housing 310 and a plurality of battery cells 200. The housing 310 has a storage cavity 311. The plurality of battery cells 200 are accommodated in the storage cavity 311.

[0015] The energy storage device 300 according to the embodiments of the present application may be at least one of an energy storage module, an energy storage cabinet, an energy storage box, an energy storage container, etc., and is not limited thereto. The energy storage device 300 according to the embodiments of the present application is used to store electrical energy and supply electrical energy to an electrical load as needed, and can be applied to a grid, a household application, an industrial application, a vehicle, etc.

[0016] Optionally, there may be a plurality of storage cavities 311. Each storage cavity 311 is used to accommodate one group of battery modules or a plurality of groups of battery modules.

[0017] Optionally, the battery cell 200 may be a rechargeable battery, a primary battery, etc., and is not limited thereto.

[0018] A secondary battery is also called a rechargeable battery or a storage battery. A secondary battery means a battery that can continue to be used by being charged after the battery discharges to activate the active material. Secondary batteries have become the main power source of electrical equipment due to their recycling characteristics.

[0019] Optionally, the plurality of battery cells 200 may be connected in series, parallel or series-parallel.

[0020] Selectively, the multiple battery cells 200 may be arranged in an array or stacked. In one specific embodiment, the multiple battery cells 200 are divided into multiple groups of battery modules. Each group of battery modules contains multiple battery cells 200. The multiple battery cells 200 in each group of battery modules are arranged in an array or stacked. The multiple groups of battery modules are arranged with spacing between them or stacked with spacing between them.

[0021] Refer to Figures 2 to 4. Embodiments of this application further provide a battery cell 200, which includes a housing 210, an end cover assembly 100, and an electrode assembly 240. The end cover assembly 100 and the housing 210 surround and form a housing cavity 230. The electrode assembly 240 is installed in the housing cavity 230 and is electrically connected to the poles 30 of the end cover assembly 100.

[0022] To make it clear, the top cover 10 of the end cover assembly 100 is connected to the housing 210. Selectively, the top cover 10 is welded to the housing 210.

[0023] Selectively, the material of the housing 210 may be, but is not limited to, aluminum.

[0024] Selectively, the battery cell 200 may be at least one of the following: a blade battery, a cylindrical battery, a prismatic battery, etc.

[0025] Selectively, the battery cell 200 may be, but is not limited to, a lithium-ion secondary battery, a lithium-ion primary battery, a lithium-sulfur battery, a sodium-lithium-ion battery, a sodium-ion battery, or a magnesium-ion battery. In the following embodiments of this application, a lithium-ion battery is described as an example, but this should not be understood as limiting the battery cell 200 of the embodiments of this application, nor should it be understood as limiting the end cover assembly 100 of the embodiments of this application.

[0026] Selectively, the electrode assembly 240 includes a positive electrode sheet 241, a separator 242, and a negative electrode sheet 243. The separator 242 is located between the positive electrode sheet 241 and the negative electrode sheet 243 and is used to insulate the positive electrode sheet 241 from the negative electrode sheet 243. The electrode assembly 240 may, but is not limited to, a wound structure, a laminated structure, or the like.

[0027] Selectively, pole 30 may be either a positive pole 30a or a negative pole 30b. When pole 30 is a positive pole 30a, it is electrically connected to the positive electrode sheet 241. When pole 30 is a negative pole 30b, it is electrically connected to the negative electrode sheet 243.

[0028] Selectively, the end cover assembly 100 includes a positive pole 30a and a negative pole 30b. The positive pole 30a is positioned to be insulated from the negative pole 30b.

[0029] Selectively, the battery cell 200 further contains an electrolyte. The electrolyte is placed in the housing cavity 230.

[0030] Selectively, the electrolyte contains an electrolyte salt and an organic solvent. The electrolyte salts include lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(oxalato)borate (LiBOB), lithium difluorobis(oxalato)phosphate (LiODFP), lithium difluoro(oxalato)borate (LiODFB), lithium difluorophosphate (LiPO2F2), and lithium trifluoromethanesulfonate (Lithium It may be at least one of the following, but is not limited to trifluoromethanesulfonate (CF3SO3Li):

[0031] In conventional technology, the end cover assembly of a battery cell requires the use of an upper plastic material so that the electrode posts and retaining rings are insulated from the top cover. Furthermore, a sealing ring must be installed between the top cover and the electrode posts. The upper plastic material, electrode posts, retaining ring, and top cover work together to compress the sealing ring, preventing leakage (i.e., electrolyte leakage) from the battery cell. However, the upper plastic material is made of resin. If thermal runaway occurs in the battery cell, the cell temperature rises, making the upper plastic material more prone to melting. This causes the electrode posts to sink into the upper plastic material, resulting in reduced compression of the sealing ring, increased electrolyte leakage from the battery cell, and a decrease in the safety of the battery cell.

[0032] Refer to Figures 4 to 7. Embodiments of this application provide an end cover assembly 100, which includes a top cover 10, an upper plastic material 20, a pole post 30, and a support portion 40. The top cover 10 has a first surface 11 and a second surface 12 that are positioned opposite each other along its thickness direction. The top cover 10 further has through holes 13, which penetrate the first surface 11 and the second surface 12, respectively. The upper plastic material 20 is positioned on the first surface 11 side of the top cover 10 and is partially drilled into the through holes 13. The upper plastic material 20 has spaced through holes 21 and mounting holes 22. The upper plastic material 20 has a first orthographic projection onto the first surface 11. The pole post 30 includes a connecting flange portion 31 and a drilled portion 32. The flange portion 31 is located on one side of the upper plastic material 20 away from the top cover 10 and is in contact with the upper plastic material 20. The drilled portion 32 is a projection on one side of the flange portion 31 facing the first surface 11 and is drilled in the through hole 21. The flange portion 31 has a second orthographic projection on the first surface 11. The support portion 40 is drilled in the mounting hole 22. Along the alignment direction of the first surface 11 and the second surface 12, the support portion 40 is located between the flange portion 31 and the top cover 10. The support portion 40 has a third orthographic projection on the first surface 11. The third orthographic projection partially overlaps with the first orthographic projection and partially overlaps with the second orthographic projection.

[0033] When the end cover assembly 100 is assembled to the battery cell, the first surface 11 is further from the inside of the battery cell than the second surface 12. In other words, the second surface 12 is further from the outer surface of the battery cell than the first surface 11. In other words, the first surface 11 is closer to the outer surface of the battery cell than the second surface 12.

[0034] Selectively, the material of the top cover 10 may be, but is not limited to, aluminum. For example, a smooth aluminum sheet may be used.

[0035] To make it easier to understand, the upper plastic material 20 is used to insulate the top cover 10 from the poles 30 so as to prevent a short circuit between the positive pole 30a and the negative pole 30b.

[0036] To make it clear, the upper plastic material 20 is located partially within the through-hole 13 and partially on one side away from the second surface 12 of the top cover 10.

[0037] Selectively, the number of mounting holes 22 may be one or multiple. If there are multiple mounting holes 22, the multiple mounting holes 22 are installed at intervals surrounding the outer circumference of the through hole 21. In one specific embodiment, the multiple mounting holes 22 are uniformly distributed around the outer circumference of the through hole 21.

[0038] Selectively, the number of support parts 40 may be one or multiple. If there are multiple support parts 40, the multiple support parts 40 are installed at intervals around the outer circumference of the through hole 21. Selectively, the number of support parts 40 corresponds one-to-one with the number of mounting holes 22. In other words, one support part 40 is located in one mounting hole 22, and different support parts 40 are located in different mounting holes 22.

[0039] Selectively, the number of support parts 40 may range from one to eight. Specifically, the number of support parts 40 may be one, two, three, four, five, six, seven, eight, etc., and is not limited to these.

[0040] Selectively, the support portion 40 forms an interlocking fit with the upper plastic material 20.

[0041] To make it easier to understand, the flange portion 31 and the drilled portion 32 are arranged along the thickness direction of the top cover 10. Along the direction perpendicular to the thickness direction of the top cover 10, the radial dimension of the flange portion 31 is greater than the radial dimension of the drilled portion 32.

[0042] To make it clear, the flange portion 31 is located on the first surface 11 side of the top cover 10, that is, the flange portion 31 is installed away from the second surface 12. Also to make it clear, when assembling the pole column 30, the drilled portion 32 is drilled into the through hole 21 from the first surface 11 toward the second surface 12.

[0043] Furthermore, the third orthographic projection partially overlaps with the first orthographic projection and partially overlaps with the second orthographic projection. To make it clear, along the thickness direction of the top cover 10, the support portion 40 partially overlaps with the flange portion 31 and partially overlaps with the upper plastic material 20.

[0044] Selectively, the end cover assembly 100 further includes a seal ring 50 and a retaining ring 60. The seal ring 50 is positioned on one side of the top cover 10 away from the upper plastic material 20 and is sleeved around the outer circumference of the drilled section 32. The retaining ring 60 is positioned on one side of the seal ring 50 away from the top cover 10. The retaining ring 60 is sleeved around the drilled section 32 and is electrically connected to the drilled section 32. The flange 31, the upper plastic material 20, the top cover 10, and the retaining ring 60 cooperate to compress the seal ring 50.

[0045] When assembling the end cover assembly 100, the drilled portions 32 of the pole column 30 are drilled sequentially into the upper plastic material 20, the top cover 10, the seal ring 50, and the retaining ring 60.

[0046] After the end cover assembly 100 is assembled, the seal ring 50 of the end cover assembly 100 has a certain amount of compression (i.e., the seal ring 50 is elastic). That is, when the seal ring 50 is assembled to the end cover assembly 100, the seal ring 50 is in a compressed state. This allows for better sealing of the gap between the top cover 10 and the pole 30, and as a result, better prevention of electrolyte leakage within the battery cell.

[0047] An end cover assembly according to an embodiment of this application includes a top cover 10, an upper plastic material 20, a pole post 30, and a support portion 40. The top cover 10 further has a through hole 13. The upper plastic material 20 is installed on the first surface 11 side of the top cover 10 and is partially drilled in the through hole 13. The upper plastic material 20 has spaced through holes 21 and mounting holes 22. The pole post 30 includes a connecting flange portion 31 and a drilled portion 32. The flange portion 31 is located on one side of the upper plastic material 20 away from the top cover 10 and abuts against the upper plastic material 20. The drilled portion 32 is convex on one side of the flange portion 31 toward the first surface and is drilled in the through hole 21. The support portion 40 is drilled in the mounting hole 22. In this embodiment, when thermal runaway occurs in the battery cell or when assembling the end cover assembly 100, the temperature of the pole column 30 rises, causing the upper plastic material 20 to melt, releasing the repulsive force from the seal ring 50, and the pole column 30 to sink (i.e., the flange portion 31 moves toward the top cover 10). By installing the support portion 40 inside the upper plastic material 20, after the pole column 30 sinks to a certain distance, the support portion 40 contacts and supports the flange portion 31, thereby preventing the pole column 30 from continuing to sink and preventing the repulsive force from the seal ring 50 from being fully released. As a result, leakage of electrolyte from the battery cell can be better avoided, and the safety of using the battery cell can be improved.

[0048] In the conventional technology, the mounting hole 22 penetrates the entire upper plastic material 20 to facilitate the support portion 40 having a more appropriate height. This better prevents the release of repulsive force by the seal ring 50 when the temperature of the pole column 30 rises. The support portion 40 forms an interlocking fit with the upper plastic material 20. However, when assembling the end cover assembly 100, the upper plastic material 20 and the support portion 40 are usually assembled first, and then transferred to the next station to assemble the other components. During transfer, the support portion 40 is prone to falling off the upper plastic material 20, thereby reducing the assembly yield of the support portion 40. If the support portion 40 is missing from the end cover assembly 100, the safety of the battery cell is reduced.

[0049] The upper plastic material 20 according to the embodiment of this application has a first orthographic projection on its first surface 11. The flange portion 31 has a second orthographic projection on its first surface 11. The support portion 40 has a third orthographic projection on its first surface 11. The third orthographic projection partially overlaps with the first orthographic projection and partially overlaps with the second orthographic projection. Because the third orthographic projection partially overlaps with the second orthographic projection, the support portion 40 can properly support the flange portion 31 when the temperature inside the battery cell rises. Furthermore, the partial overlap of the third orthographic projection with the first orthographic projection means that the support portion 40 can be attached to the upper plastic material 20, and the support portion can be supported by the overlapping portion of the upper plastic material 20 and the support portion 40. This makes it possible to better prevent the support part 40 from being detached from the upper plastic material when the assembly of the support part 40 / upper plastic material 20 is transferred to the next station, improving the assembly yield of the upper plastic material 20 and the support part 40, and consequently improving the safety of the battery cell.

[0050] In some embodiments, the melting point of the support portion 40 is greater than that of the upper plastic material 20, and the melting point of the upper plastic material 20 of the end cover assembly 100 is lower than that of the seal ring 50. If thermal runaway occurs in the battery cell, the upper plastic material 20 melts, but the support portion 40 and seal ring 50 do not melt, and as a result the pole column 30 sinks, the support portion 40 can properly support the flange portion 31 of the pole column 30, preventing the pole column 30 from continuing to sink and preventing the repulsive force from the seal ring 50 from being fully released. As a result, leakage of electrolyte from the battery cell can be better avoided, and the safety of using the battery cell can be improved.

[0051] Selectively, both the upper plastic material 20 and the seal ring 50 are made of resin.

[0052] Selectively, the melting point of the seal ring 50 is greater than the melting point of the upper plastic material 20. In some embodiments, the melting point range of the upper plastic material 20 is 280°C to 300°C, and the melting point of the seal ring 50 is 500°C or higher.

[0053] In the embodiments of this application, unless otherwise specified, the numerical range a to b may be any numerical value between a and b, and includes endpoint values ​​a and b.

[0054] Selectively, the melting point of the support portion 40 is 500°C or higher. Specifically, the melting point of the support portion 40 may be, but is not limited to, 500°C, 550°C, 600°C, 650°C, 700°C, 800°C, 900°C, 1000°C, 1100°C, 1200°C, 1300°C, etc. If the melting point of the support portion 40 is too low, when thermal runaway occurs in the battery cell, the support portion 40 will soften and eventually melt, thereby reducing the support effect of the support portion 40 on the retaining ring 60. The higher the melting point of the support portion 40, the better. However, this is difficult to achieve from a material standpoint.

[0055] Selectively, the support portion 40 is insulating. Selectively, the material of the support portion 40 may be, but is not limited to, ceramic.

[0056] In some embodiments, the area of ​​the region where the third orthographic projection overlaps with the first orthographic projection is smaller than the area of ​​the region where the third orthographic projection overlaps with the second orthographic projection.

[0057] To make it easier to understand, the area of ​​the support portion 40 that overlaps with the flange portion 31 is larger than the area of ​​the support portion 40 that is laminated with the upper plastic material 20.

[0058] If thermal runaway occurs in the battery cell and the upper plastic material 20 melts, the flange portion 31 of the pole column 30 maintains a constant distance from the top cover 10 with the support portion 40, thereby preventing the pole column 30 from sinking. If the area of ​​the portion where the support portion 40 overlaps with the flange portion 31 is too small, the repulsive force from the seal ring 50 will cause the support portion 40 to lose balance, resulting in tilting or rotation, which will push the support portion 40 out from between the flange portion 31 and the top cover 10. Furthermore, without the support of the support portion 40, the seal by the seal ring 50 will be insufficient, causing leakage from the battery cell and reducing the safety of the battery cell. In this embodiment, the area of ​​the portion where the third orthographic projection overlaps with the first orthographic projection is smaller than the area where the third orthographic projection overlaps with the second orthographic projection. Thus, the portion where the support portion 40 overlaps with the flange portion 31 is relatively large. Even if thermal runaway occurs in the battery cell and the upper plastic material 20 melts, the support part 40 is not pushed out from between the flange part 31 and the top cover 10 by the repulsive force of the seal ring 50. As a result, the support part 40 can always support the flange part 31, and the release of the repulsive force of the seal ring 50 can be better prevented. Consequently, the battery cell always maintains good sealing performance, better preventing leakage from the battery cell and improving the safety of using the battery cell.

[0059] Selectively, the area of ​​the region where the third orthographic projection overlaps with the second orthographic projection is at least half the area of ​​the third orthographic projection.

[0060] In other words, the area of ​​the overlapping portion of the support portion 40 and the flange portion 31 is at least half the area of ​​the orthographic projection on the first surface 11 of the support portion 40.

[0061] If thermal runaway occurs in the battery cell and the upper plastic material 20 melts, the flange portion 31 of the pole column 30 maintains a constant distance from the top cover 10 with the support of the support portion 40, thereby preventing the pole column 30 from sinking. If the area of ​​the portion where the support portion 40 overlaps with the flange portion 31 is too small, the repulsive force from the seal ring 50 will cause the support portion 40 to lose balance, resulting in tilting or rotation, which will push the support portion 40 out from between the flange portion 31 and the top cover 10. Furthermore, without the support of the support portion 40, the seal by the seal ring 50 will be insufficient, causing leakage from the battery cell and reducing the safety of the battery cell. In this embodiment, the area of ​​the portion where the third orthographic projection overlaps with the second orthographic projection is 1 / 2 or more of the area of ​​the third orthographic projection. Thus, the portion where the support portion 40 overlaps with the flange portion 31 is relatively large. Even if thermal runaway occurs in the battery cell and the upper plastic material 20 melts, the support part 40 is not pushed out from between the flange part 31 and the top cover 10 by the repulsive force of the seal ring 50. As a result, the support part 40 can always support the flange part 31, and the release of the repulsive force of the seal ring 50 can be better prevented. Consequently, the battery cell always maintains good sealing performance, better preventing leakage from the battery cell and improving the safety of using the battery cell.

[0062] Refer to Figures 8 to 10. In some embodiments, the distance between the surface of the flange portion 31 facing the top cover 10 and the first surface 11 is d1. Along the thickness direction of the top cover 10, the height of the support portion 40 is h1, and d1 > h1.

[0063] To make it clear, the gap between the flange portion 31 and the first surface 11 is greater than the height of the support portion 40.

[0064] In this embodiment, by making the distance d1 between the surface of the flange portion 31 facing the top cover 10 and the first surface 11 larger than the height h1 of the support portion 40 along the thickness direction of the top cover 10, when assembling the end cover assembly 100, the flange portion 31 can be pushed up by the support portion 40, and it is possible to prevent a gap from being formed between the flange portion 31 and the upper plastic material 20. As a result, the stability of the compression amount of the seal ring 50 is reduced, and the compression amounts of the upper plastic material 20 and the seal ring 50 of different end cover assemblies 100 are different, and it is possible to better avoid the reduction in the dimensional stability of the end cover assembly 100.

[0065] In some embodiments, the end cover assembly 100 satisfies the relational expression of 0 < d1 - h1 ≤ 0.1 mm.

[0066] As can be understood, the range of the difference between the distance d1 between the surface of the flange portion 31 facing the top cover 10 and the first surface 11 and the height h1 of the support portion 40 along the thickness direction of the top cover 10 is 0 to 0.1 mm.

[0067] Specifically, the difference between the distance d1 between the surface of the flange portion 31 facing the top cover 10 and the first surface 11 and the height h1 of the support portion 40 along the thickness direction of the top cover 10 may be 0.01 mm, 0.02 mm, 0.03 mm, 0.04 mm, 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm, etc., and is not limited thereto.

[0068] In this embodiment, if the difference d1-h1 between the distance d1 between the surface of the flange portion 31 facing the top cover 10 and the first surface 11, and the height h1 of the support portion 40 along the thickness direction of the top cover 10, is too large, then if thermal runaway occurs in the battery cell, the distance between the support portion 40 and the flange portion 31 will be too large, reducing the support effect of the support portion 40 on the flange portion 31. This makes it difficult to prevent the pole column 30 from sinking excessively, reducing the amount of compression of the seal ring 50 and decreasing the sealing performance of the seal ring 50, which in turn increases the risk of electrolyte leakage from the battery cell. When the range of the difference between the distance d1 between the surface of the flange portion 31 facing the top cover 10 and the first surface 11, and the height h1 of the support portion 40 along the thickness direction of the top cover 10 is 0 to 0.1 mm, after assembling the end cover assembly 100, the flange portion 31 will not be easily pushed up by the support portion 40, thereby better ensuring the stability of the compression amount of the seal ring 50. Furthermore, if thermal runaway occurs in the battery cell, the support portion 40 supports the flange portion 31, preventing the pole column 30 from sinking excessively, thereby better preventing electrolyte leakage from the battery cell.

[0069] Furthermore, the difference between the distance d1 between the surface of the flange portion 31 facing the top cover 10 and the first surface 11, and the height h1 of the support portion 40 along the thickness direction of the top cover 10, is in the range of 0.03 mm to 0.1 mm. In this way, after assembling the end cover assembly 100, the flange portion 31 is not pushed up any more easily by the support portion 40, thereby better ensuring the stability of the compression amount of the seal ring 50. Also, if thermal runaway occurs in the battery cell, the support portion 40 can better support the flange portion 31 and better prevent the pole column 30 from sinking excessively, thereby better preventing electrolyte leakage from the battery cell.

[0070] In some embodiments, the distance d1 between the surface of the flange portion 31 facing the top cover 10 and the first surface 11 is 0.9 mm to 1.2 mm. Specifically, the distance d1 between the surface of the flange portion 31 facing the top cover 10 and the first surface 11 may be, but is not limited to, 0.9 mm, 0.95 mm, 1.0 mm, 1.05 mm, 1.1 mm, 1.15 mm, 1.2 mm, etc. If the distance d1 between the surface of the flange portion 31 facing the top cover 10 and the first surface 11 is too small, there will be too little space for the upper plastic material 20, which will only allow the upper plastic material 20 to be made thinner, resulting in a decrease in the mechanical strength of the upper plastic material 20. If the distance d1 between the surface of the flange portion 31 facing the top cover 10 and the first surface 11 is too large, the upper plastic material 20 will be too thick, which will increase the cost of the upper plastic material 20.

[0071] In some embodiments, the height h1 of the support portion 40 along the thickness direction of the top cover 10 is in the range of 0.85 mm to 1.15 mm. Specifically, the height h1 of the support portion 40 along the thickness direction of the top cover 10 may be, but is not limited to, 0.85 mm, 0.9 mm, 0.95 mm, 1.0 mm, 1.05 mm, 1.1 mm, 1.15 mm, etc. If the height h1 of the support portion 40 is too small, if thermal runaway occurs in the battery cell, the distance between the support portion 40 and the flange portion 31 will be too large, reducing the support effect of the support portion 40 on the flange portion 31. This makes it difficult to prevent the pole column 30 from sinking excessively, reducing the amount of compression of the seal ring 50, decreasing the sealing performance of the seal ring 50, and consequently increasing the risk of electrolyte leakage from the battery cell. If the height h1 of the support portion 40 is too large, after assembling the end cover assembly 100, the flange portion 31 is easily pushed up by the support portion 40, creating a gap between the flange portion 31 and the upper plastic material 20. As a result, the stability of the compression amount of the seal ring 50 decreases, and the compression amounts of the upper plastic material 20 and the seal ring 50 differ among different end cover assemblies 100, reducing the dimensional stability of the end cover assembly 100.

[0072] Refer to Figure 11. In some embodiments, the upper plastic material 20 includes a first plastic portion 23, a second plastic portion 24, and a third plastic portion 25 that are sequentially folded and connected. The first plastic portion 23 and the third plastic portion 25 are each folded in a direction opposite to the second plastic portion 24. The first plastic portion 23 is drilled in a through-hole 13 and has a through hole 21. The second plastic portion 24 and the third plastic portion 25 form a support groove 26, which is configured to support the flange portion 31. Two surfaces of the second plastic portion 24 that are opposite to each other along the thickness direction of the top cover 10 abut the first surface 11 and the flange portion 31, respectively. A mounting hole 22 is formed between the second plastic portion 24 and the third plastic portion 25. The mounting hole 22 penetrates the surface of the second plastic portion 24 facing the first surface 11 and the surface of the third plastic portion 25 facing the first surface 11, respectively. The mounting hole 22 further penetrates the surface of the second plastic part 24 away from the first surface 11. The third plastic part 25 has a stepped surface 27. The stepped surface 27 is located on one side of the support part 40 away from the first surface 11 and faces the support part 40. The orthographic projection of the stepped surface 27 on the first surface 11 partially overlaps with the orthographic projection of the third.

[0073] To make it easier to understand, the second plastic part 24 is installed surrounding the outer periphery of the first plastic part 23. The third plastic part 25 is installed surrounding the outer periphery of the second plastic part 24.

[0074] To make it clear, the first plastic part 23, the second plastic part 24, and the third plastic part 25 are all annular structures.

[0075] To make it easier to understand, the first plastic part 23 is located between the drilling part 32 and the top cover 10. The second plastic part 24 is located between the flange part 31 and the top cover 10. The third plastic part 25 is installed surrounding the outer circumference of the flange part 31.

[0076] To make it easier to understand, the flange portion 31 abuts against the bottom wall of the support groove 26. In other words, the flange portion 31 abuts against the second plastic portion 24.

[0077] To make it easier to understand, the mounting hole 22 is located partially on the second plastic part 24 and partially on the first plastic part 23.

[0078] To make it clear, the mounting hole 22 does not penetrate the surface of the third plastic part 25 that is away from the first surface 11.

[0079] Furthermore, the portion of the stepped surface 27 where the orthographic projection of the first surface 11 overlaps with the third orthographic projection is the same as the portion where the first orthographic projection overlaps with the third orthographic projection.

[0080] To make it easier to understand, the orthographic projection of the first surface 11 of the upper plastic material 20 coincides with the orthographic projection of the first surface 11 of the support portion 40 only at the stepped surface 27.

[0081] In this embodiment, a stepped surface 27 is provided on the third plastic part 25. In this way, if the support part 40 / upper plastic part 20 assembly needs to be transported to the next station after the support part 40 has been assembled to the upper plastic part 20, the support part 40 can be supported by the stepped surface 27 of the third plastic part 25 by orienting the first plastic part 23 upward compared to the third plastic part 25, thereby preventing the support part 40 from falling off the upper plastic part 20, improving the assembly yield of the upper plastic part 20 and the support part 40, and consequently improving the safety of the battery cell. In addition, the mounting hole 22 penetrates the surface of the second plastic part 24 facing the first surface 11 and the surface of the third plastic part 25 facing the first surface 11, respectively. In this way, when the support part 40 is to be installed, it can be installed from one side facing the first surface 11 of the second plastic part 24. This does not affect the installation of the support part 40. Furthermore, a stepped surface 27 is provided on the third plastic part 25. In this way, there is no need to change the size of each part of the upper plastic material 20, that is, there is no need to redesign the thickness and other sizes of the first plastic part 23, the second plastic part 24, and the third plastic part 25, and this does not excessively affect the manufacturing cost of the end cover assembly 100.

[0082] In some embodiments, a gap w1 is formed between the flange portion 31 and the third plastic portion 25 in the radial direction of the support groove 26. The width of the support portion 40 is w2, the width of the stepped surface 27 is w3, and w2-w1 is 0.1mm ≤ w3 ≤ 1 / 2.

[0083] To make it clear, a gap w1 is formed between the flange portion 31 and the third plastic portion 25 in the radial direction of the support groove 26. In the radial direction of the support groove 26, the width of the support portion 40 is w2. In the radial direction of the support groove 26, the width of the stepped surface 27 is w3.

[0084] Specifically, the width of the stepped surface 27 may be 0.1 mm, 0.13 mm, 0.15 mm, 0.18 mm, 0.2 mm, 0.23 mm, 0.25 mm, 0.28 mm, 0.3 mm, etc., and is not limited to these.

[0085] In this embodiment, the width w3 of the stepped surface 27 is too small. Thus, if the support part 40 / upper plastic material 20 assembly needs to be transported to the next station after the support part 40 has been assembled to the upper plastic material 20, the support of the support part 40 by the stepped surface 27 is insufficient, which may cause the support part 40 to detach from the upper plastic material 20, reducing the assembly yield of the upper plastic material 20 and the support part 40, and consequently reducing the safety of the battery cell. If the width w3 of the stepped surface 27 is too large, the portion of the support part 40 that overlaps with the flange part 31 becomes small. Thus, if thermal runaway occurs in the battery cell and the upper plastic material 20 melts, and the support part 40 comes into contact with the flange part 31, the repulsive force from the seal ring 50 will cause the support part 40 to lose balance, resulting in tilting or rotation, which will push the support part 40 out from between the flange part 31 and the top cover 10. Furthermore, without support from the support portion 40, the seal by the seal ring 50 would be insufficient, causing leakage from the battery cell and reducing the safety of the battery cell. When the width w3 of the stepped surface 27 is w2-w1 such that 0.1mm ≤ w3 ≤ 1 / 2, the support portion 40 can be better prevented from falling off the upper plastic material 20 when the assembly of the support portion 40 / upper plastic material 20 is transferred to the next station, improving the assembly yield of the upper plastic material 20 and the support portion 40. In addition, if thermal runaway occurs in the battery cell and the upper plastic material 20 melts, and the support portion 40 comes into contact with the flange portion 31, the support portion 40 can be better prevented from being pushed out from between the flange portion 31 and the top cover 10, thereby ensuring that the support portion 40 always supports the flange portion 31 and better preventing the release of the repulsive force by the seal ring 50. As a result, the battery cell always maintains good sealing performance, better preventing leakage from the battery cell and improving the safety of using the battery cell.

[0086] Optionally, in the radial direction of the support groove 26, the gap w1 between the flange portion 31 and the third plastic portion 25 satisfies 0 < w1 ≦ 0.1 mm. Specifically, in the radial direction of the support groove 26, the gap w1 between the flange portion 31 and the third plastic portion 25 may be 0.01 mm, 0.02 mm, 0.04 mm, 0.06 mm, 0.08 mm, 0.1 mm, etc., and is not limited thereto. If the gap w1 between the flange portion 31 and the third plastic portion 25 is too small, it will affect the assembly of the terminal 30. If the gap w1 between the flange portion 31 and the third plastic portion 25 is too large, the terminal 30 is likely to sink.

[0087] In some embodiments, in the radial direction of the support groove 26, the width of the portion where the third orthographic projection overlaps the second orthographic projection is b1. A gap w1 is formed between the flange portion 31 and the third plastic portion 25. The width of the support portion 40 is w2. The width of the stepped surface 27 is w3. In this case, 1 / 2 of w2 ≦ b1 ≦ w2 - w1 - w3.

[0088] If thermal runaway occurs in the battery cell and the upper plastic material 20 melts, the flange portion 31 of the pole column 30 maintains a constant distance from the top cover 10 with the support portion 40, thereby preventing the pole column 30 from sinking. If the area of ​​the part where the support portion 40 overlaps with the flange portion 31 is too small, the repulsive force from the seal ring 50 will cause the support portion 40 to lose balance, resulting in tilting or rotation, which will push the support portion 40 out from between the flange portion 31 and the top cover 10. Furthermore, without the support of the support portion 40, the seal by the seal ring 50 will be insufficient, causing leakage from the battery cell and reducing the safety of the battery cell. In this embodiment, w2 ≤ b1 ≤ w2 - w1 - w3 of 1 / 2. Thus, the area where the support portion 40 overlaps with the flange portion 31 is relatively large. Even if thermal runaway occurs in the battery cell and the upper plastic material 20 melts, the support part 40 is not pushed out from between the flange part 31 and the top cover 10 by the repulsive force of the seal ring 50. As a result, the support part 40 can always support the flange part 31, and the release of the repulsive force of the seal ring 50 can be better prevented. Consequently, the battery cell always maintains good sealing performance, better preventing leakage from the battery cell and improving the safety of using the battery cell.

[0089] Refer to Figure 12. In some embodiments, the inner wall of the mounting hole 22 includes a first wall surface 221, a first curved surface 222, a second wall surface 223, and a second curved surface 224, to which the ends are connected in sequence. The first wall surface 221 and the second wall surface 223 are both located on the second plastic portion 24. The first wall surface 221, the second wall surface 223, and the stepped surface 27 are spaced apart and surround the outer circumference of the mounting hole 22. The stepped surface 27 is connected to the first curved surface 222. The second curved surface 224, the first wall surface 221, and the second wall surface 223 are all located on the second plastic portion 24. The support portion 40 abuts against the first wall surface 221, the second wall surface 223, and the first curved surface 222, respectively. The support portion 40 and the second curved surface 224 are spaced apart.

[0090] Selectively, the first arc surface 222 may be at least one of the following: a circular arc surface, an elliptical arc surface, a nearly circular arc surface, a nearly elliptical arc surface, etc., and is not limited to these.

[0091] Selectively, the second arc surface 224 may be at least one of the following: a circular arc surface, an elliptical arc surface, a nearly circular arc surface, a nearly elliptical arc surface, etc., and is not limited to these.

[0092] Selectively, the first wall surface 221 may be a plane, but is not limited to that.

[0093] Selectively, the second wall surface 223 may be, but is not limited to, a plane.

[0094] In this embodiment, the support portion 40 abuts against the first wall surface 221, the second wall surface 223, and the first curved surface 222, respectively. In this way, the support portion 40 forms an interference fit with the upper plastic material 20, thereby preventing the support portion 40 from falling off the upper plastic material 20 during the subsequent assembly process and improving the assembly yield of the end cover assembly 100. The support portion 40 is also installed with a gap between it and the second curved surface 224. In this way, when the support portion 40 is assembled to the upper plastic material 20, the gap between the support portion 40 and the second curved surface 224 provides room for plastic deformation in the upper plastic material 20, thereby better avoiding cracking of the upper plastic material 20 due to excessive pressing force when assembling the support portion 40, and as a result, improving the assembly yield of the support portion 40 and the upper plastic material 20.

[0095] Refer to Figure 13. In some other embodiments, the upper plastic material 20 includes a first plastic section 23, a second plastic section 24, and a third plastic section 25 that are sequentially folded and connected. The first plastic section 23 and the third plastic section 25 are each folded in a direction opposite to the second plastic section 24. The first plastic section 23 is drilled in a through-hole 13 and has a through hole 21. The second plastic section 24 and the third plastic section 25 surround each other to form a support groove 26, which is configured to support the flange section 31. The two surfaces of the second plastic section 24 that are opposite to each other along the thickness direction of the top cover 10 abut against the first surface 11 and the flange section 31, respectively. The second plastic section 24 has mounting holes 22. In the direction from the top cover 10 toward the support section 40, the radial dimension of the mounting holes 22 gradually decreases, and the radial dimension of the support section 40 also gradually decreases. The outer peripheral wall of the support portion 40 abuts against the inner wall of the mounting hole 22.

[0096] Selectively, the shape of the mounting hole 22 may be a frustoconical shape, but is not limited thereto. The shape of the support portion 40 may be a frustoconical shape, but is not limited thereto.

[0097] In this embodiment, the radial dimension of the mounting hole 22 gradually decreases in the direction from the top cover 10 toward the support portion 40, and the radial dimension of the support portion 40 also gradually decreases. The outer peripheral side wall of the support portion 40 abuts against the inner wall of the mounting hole 22. As a result, the third orthographic projection and the first orthographic projection are partially overlapped. In this way, if the support portion 40 / upper plastic material 20 assembly needs to be transferred to the next station after the support portion 40 has been assembled to the upper plastic material 20, the support portion 40 can be supported by the second plastic portion 24 by orienting the first plastic portion 23 upward compared to the third plastic portion 25, thereby preventing the support portion 40 from falling off the upper plastic material 20, improving the assembly yield of the upper plastic material 20 and the support portion 40, and consequently improving the safety of the battery cell. Thus, when the support portion 40 is to be installed, it can be installed from one side facing the first surface 11 of the second plastic portion 24. This is advantageous for the rapid installation of the support portion 40 and improves the efficiency of the installation of the support portion 40.

[0098] Refer to Figures 14 and 15. In some other embodiments, the upper plastic material 20 includes a first plastic portion 23, a second plastic portion 24, and a third plastic portion 25 that are sequentially folded and connected. The first plastic portion 23 and the third plastic portion 25 are each folded in a direction opposite to the second plastic portion 24. The first plastic portion 23 is drilled in a through hole 13 and has a through hole 21. The second plastic portion 24 and the third plastic portion 25 surround each other to form a support groove 26, which is configured to support the flange portion 31. The two surfaces of the second plastic portion 24 that are opposite to each other along the thickness direction of the top cover 10 abut against the first surface 11 and the flange portion 31, respectively. The second plastic portion 24 has a mounting hole 22. The support portion 40 includes a first support portion 41 and a second support portion 42 that are connected. The first support portion 41 and the second support portion 42 are arranged along the thickness direction of the top cover 10. The radial dimension of the first support portion 41 is greater than the radial dimension of the second support portion 42. The first support portion 41 is located between the flange portion 31 and the second plastic portion 24, or between the second plastic portion 24 and the top cover 10. The second support portion 42 is drilled in the mounting hole 22.

[0099] As shown in Figure 14, when the first support portion 41 is located between the flange portion 31 and the second plastic portion 24, it abuts against the flange portion 31 and the second plastic portion 24, respectively. As shown in Figure 15, when the first support portion 41 is located between the second plastic portion 24 and the top cover 10, it abuts against the second plastic portion 24 and the top cover 10, respectively.

[0100] To make it clear, in this embodiment, the portion where the third orthographic projection overlaps with the first orthographic projection is within the range of the orthographic projection on the first surface 11 of the first support portion 41. The portion where the third orthographic projection overlaps with the second orthographic projection is within the range of the orthographic projection on the first surface 11 of the second support portion 42.

[0101] In this embodiment, the support portion 40 includes a first support portion 41 and a second support portion 42 that are connected. The first support portion 41 and the second support portion 42 are arranged along the thickness direction of the top cover 10. The radial dimension of the first support portion 41 is greater than the radial dimension of the second support portion 42. The first support portion 41 is located between the flange portion 31 and the second plastic portion 24, or between the second plastic portion 24 and the top cover 10. The second support portion 42 is drilled in the mounting hole 22. Due to the positional limiting effect of the second support portion 42 and the second plastic portion 24, if the support portion 40 / upper plastic portion 20 assembly needs to be transferred to the next station after the support portion 40 has been assembled to the upper plastic portion 20, the support portion 40 can be supported by the second plastic portion 24 by orienting the first support portion 41 upward compared to the second plastic portion 24, thereby preventing the support portion 40 from falling off the upper plastic portion 20, improving the assembly yield of the upper plastic portion 20 and the support portion 40, and consequently improving the safety of the battery cell. In addition, the radial dimension of the mounting hole 22 gradually decreases, and the radial dimension of the support portion 40 also gradually decreases. In this way, when the support portion 40 is to be installed, it can be installed from one side facing the first surface 11 of the second plastic portion 24. This is advantageous for the rapid installation of the support portion 40 and improves the efficiency of the installation of the support portion 40.

[0102] Refer again to Figures 4 to 6. In some embodiments, the end cover assembly 100 further includes a lower plastic material 70 and a top patch 80. The lower plastic material 70 is installed on one side of the top cover 10 away from the upper plastic material 20. The lower plastic material 70 is installed around the outer circumference of the retaining ring 60, the sealing ring 50 and the drilled section 32. The lower plastic material 70 is used to insulate the top cover 10 from the electrode assembly 240. The top patch 80 is installed on the first surface 11 of the top cover 10 and around the outer circumference of the upper plastic material 20. The top patch is used to insulate the top cover 10 from the outside and to protect the top cover 10.

[0103] When assembling the end cover assembly 100, the drilled portion 32 of the pole column 30 is drilled sequentially into the upper plastic material 20, top patch 80, top cover 10, lower plastic material 70, seal ring 50, and retaining ring 60.

[0104] Selectively, the material of the lower plastic material 70 may be, but is not limited to, a resin material.

[0105] Selectively, the material of the top patch 80 may be, but is not limited to, a resin material.

[0106] Refer again to Figure 6. In some embodiments, the top cover 10 has a groove 14 located on and recessed into the second surface 12. The groove 14 is positioned around the outer circumference of the through hole 13. The upper plastic material 20 is partially fitted into the groove 14. The groove 14 is further used to accommodate a seal ring 50.

[0107] To make it clear, the groove 14 is used to accommodate the seal ring 50 and a portion of the upper plastic material 20.

[0108] In this embodiment, by providing a groove 14 on the second surface 12 of the top cover 10, the upper plastic material 20 is partially fitted into the groove 14. This is advantageous for assembling the upper plastic material 20 and the top cover 10. Furthermore, it is possible to better position the upper plastic material 20 and the top cover 10 and improve the efficiency of assembling the end cover assembly 100.

[0109] The terms “Examples” and “Embodiments” as used in this application mean that any particular feature, structure, or characteristic described in conjunction with an embodiment may be included in at least one embodiment of this application. The words “Examples” as used anywhere in the specification do not necessarily refer to the same embodiment, nor are they mutually exclusive, independent, or interchangeable embodiments. Those skilled in the art will understand, explicitly or implicitly, that the embodiments described in this application may be combined with other embodiments. Furthermore, the features, structures, or characteristics described in each embodiment of this application may be combined in any way, provided they do not contradict each other, to form embodiments that do not deviate from the spirit and scope of the technical invention of this application.

[0110] Finally, it should be noted that the embodiments described above are merely for illustrative purposes and not to limit the technical proposal of this application, and the application has been described in detail with reference to the preferred embodiments described above. Those skilled in the art will understand that any modification or equivalent substitution to the technical proposal of this application will not depart from the spirit and scope of the technical proposal of this application. [Explanation of symbols]

[0111] 300…Energy storage device, 310…Housing, 311…Storage cavity, 200…Battery cell, 210…Housing, 230…Accommodation cavity, 240…Electrode assembly, 241…Positive electrode sheet, 242…Separator, 243…Negative electrode sheet, 100…End cover assembly, 10…Top cover, 11…First surface, 12…Second surface, 13…Through hole, 14…Groove, 20…Upper plastic material, 21…Through hole, 22…Mounting hole, 221…First 1...Wall surface, 222...First curved surface, 223...Second wall surface, 224...Second curved surface, 23...First plastic part, 24...Second plastic part, 25...Third plastic part, 26...Support groove, 27...Stepped surface, 30...Positive pole column, 30a...Positive pole column, 30b...Negative pole column, 31...Flange part, 32...Drilled part, 40...Support part, 41...First support part, 42...Second support part, 50...Seal ring, 60...Pressing ring, 70...Lower plastic material, 80...Top patch.

Claims

1. End cover assembly, Including the top cover, upper plastic material, pole column, and support part, The top cover has a first surface and a second surface that are positioned opposite each other along its thickness direction, and the top cover further has through holes, the through holes penetrating the first surface and the second surface, respectively. The upper plastic material is installed on the first surface side of the top cover and is partially drilled into the through hole, the upper plastic material has spaced through holes and mounting holes, and the upper plastic material has a first orthographic projection on the first surface. The pole column includes a connecting flange portion and a perforated portion, the flange portion is located on one side of the upper plastic material away from the top cover and in contact with the upper plastic material, the perforated portion is convex on one side of the flange portion toward the first surface and is perforated in the through hole, and the flange portion has a second orthogonal projection on the first surface. The support portion is drilled in the mounting hole, and along the alignment direction of the first surface and the second surface, the support portion is located between the flange portion and the top cover, and the support portion has a third orthographic projection on the first surface, the third orthographic projection partially overlapping with the first orthographic projection and partially overlapping with the second orthographic projection. An end cover assembly characterized by the following features.

2. The area of ​​the portion where the third orthographic projection overlaps with the first orthographic projection is smaller than the area of ​​the portion where the third orthographic projection overlaps with the second orthographic projection. The end cover assembly according to feature 1.

3. The distance between the surface of the flange portion facing the top cover and the first surface is d1, and the height of the support portion along the thickness direction of the top cover is h1, where d1 > h1. The end cover assembly according to feature 1.

4. The end cover assembly satisfies the relationship 0 < d1 - h1 ≤ 0.1 mm. The end cover assembly according to claim 3.

5. The aforementioned upper plastic material includes a first plastic portion, a second plastic portion, and a third plastic portion which are sequentially bent and connected, the first plastic portion and the third plastic portion are each bent in a direction opposite to the second plastic portion, the first plastic portion is drilled in the through hole and has the through hole, the second plastic portion and the third plastic portion form a support groove, the support groove is configured to support the flange portion, and the two surfaces of the second plastic portion that are opposite to each other along the thickness direction of the top cover are each the first The mounting hole is formed between the second plastic part and the third plastic part, and the mounting hole penetrates the surface of the second plastic part toward the first surface and the surface of the third plastic part toward the first surface, and the mounting hole further penetrates the surface of the second plastic part away from the first surface, the third plastic part has a stepped surface, the stepped surface is located on one side away from the first surface of the support part and toward the support part, and the orthographic projection of the stepped surface on the first surface partially overlaps with the orthographic projection of the third. The end cover assembly according to feature 1.

6. In the radial direction of the support groove, a gap w1 is formed between the flange portion and the third plastic portion, the width of the support portion is w2, the width of the stepped surface is w3, and w2 - w1 is such that 0.1 mm ≤ w3 ≤ 1 / 2. The end cover assembly according to any one of the features of item 5.

7. Along the radial direction of the support groove, the width of the portion where the third orthographic projection overlaps with the second orthographic projection is b1, a gap w1 is formed between the flange portion and the third plastic portion, the width of the support portion is w2, the width of the stepped surface is w3, and w2 ≤ b1 ≤ w2 - w1 - w3, The end cover assembly according to claim 5.

8. The inner wall of the mounting hole includes a first wall surface, a first curved surface, a second wall surface, and a second curved surface to which the ends are connected in sequence, the first wall surface and the second wall surface both located on the second plastic part, the first wall surface, the second wall surface and the stepped surface are installed with spacing between them surrounding the outer circumference of the mounting hole, the stepped surface is connected to the first curved surface, the second curved surface, the first wall surface and the second wall surface all located on the second plastic part, the support part abuts against the first wall surface, the second wall surface and the first curved surface respectively, and the support part and the second curved surface are installed with spacing between them. The end cover assembly according to claim 5.

9. The aforementioned upper plastic material includes a first plastic portion, a second plastic portion, and a third plastic portion that are sequentially bent and connected, the first plastic portion and the third plastic portion are each bent in a direction opposite to the second plastic portion, the first plastic portion is drilled in the through hole and has the through hole, the second plastic portion and the third plastic portion surround each other to form a support groove, the support groove is configured to support the flange portion, the two surfaces of the second plastic portion that are opposite to each other along the thickness direction of the top cover abut the first surface and the flange portion, respectively, the second plastic portion has the mounting hole, the radial dimension of the mounting hole gradually decreases in the direction from the top cover toward the support portion, the radial dimension of the support portion also gradually decreases, and the outer peripheral side wall of the support portion abuts the inner wall of the mounting hole. The end cover assembly according to feature 1.

10. The upper plastic material includes a first plastic portion, a second plastic portion, and a third plastic portion which are sequentially bent and connected, the first plastic portion and the third plastic portion are each bent in a direction opposite to the second plastic portion, the first plastic portion is drilled in the through hole and has the through hole, the second plastic portion and the third plastic portion surround each other to form a support groove, the support groove is configured to support the flange portion, and along the thickness direction of the top cover of the second plastic portion Two opposing surfaces abut the first surface and the flange portion, respectively; the second plastic portion has the mounting hole; the support portion includes a first support portion and a second support portion to which it is connected; the first support portion and the second support portion are arranged along the thickness direction of the top cover; the radial dimension of the first support portion is greater than the radial dimension of the second support portion; the first support portion is located between the flange portion and the second plastic portion, or between the second plastic portion and the top cover; and the second support portion is drilled in the mounting hole. The end cover assembly according to feature 1.

11. The end cover assembly further includes a seal ring and a retaining ring, wherein the seal ring is positioned on one side away from the upper plastic material of the top cover and is sleeved around the outer circumference of the drilled portion, the retaining ring is positioned on one side of the seal ring away from the top cover and is sleeved around the drilled portion and electrically connected to the drilled portion, and the flange portion, the upper plastic material, the top cover and the retaining ring cooperate to compress the seal ring. The end cover assembly according to any one of claims 1 to 10, characterized in that it is as described above.

12. It is a battery cell, The housing includes the end cover assembly according to any one of claims 1 to 11 and the electrode assembly, The end cover assembly and the housing surround each other to form a housing cavity. The electrode assembly is installed in the housing cavity and electrically connected to the electrode column of the end cover assembly. A battery cell characterized by the following features.

13. An energy storage device, The housing includes a plurality of battery cells according to claim 12, The aforementioned enclosure has a storage cavity, The plurality of battery cells are housed in the storage cavity. An energy storage device characterized by the following features.

Images