End cover assembly, battery, energy storage device and electrical system

Abstract

An end cover assembly (10), comprising: a top cover unit (100); poles (400) which pass through the top cover unit (100) and each comprise a base portion (410) and a connecting portion (420), wherein the connecting portion (420) protrudes from the end surface of the base portion (410) along the axial direction of the base portion (410), and the portion of the end surface of the base portion (410) located outside the coverage of the connecting portion (420) forms a stepped surface (411) surrounding the connecting portion (420); an upper plastic (200) at least partially sleeved on the outer peripheral side of the base portion (410), wherein a portion of the upper plastic (200) is located on one side of the top cover unit (100) in the thickness direction; and a fixing member (300), wherein a portion of the fixing member (300) is located on the other side of the top cover unit (100) in the thickness direction, a seam (310) surrounding the connecting portion (420) is formed between the fixing member (300) and the connecting portion (420), and the stepped surface (411) abuts against the fixing member (300) and covers the seam (310).

Description

End cover components, batteries, energy storage equipment and power systems Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to an end cover assembly, a battery, an energy storage device, and an electricity system. Background Art

[0002] Rechargeable batteries, also known as rechargeable batteries or storage batteries, can be recharged after discharge to reactivate their active materials for continued use. Their recyclable nature makes them a key power source for electrical systems. Rechargeable batteries typically include end cap assemblies. However, during assembly, welding heat can damage other components within the assembly, causing partial failure and compromising the reliability of the entire assembly.

[0003] Summary of the Invention

[0004] A technical problem solved by this application is how to improve the reliability of the end cover assembly.

[0005] An end cap assembly, characterized by comprising:

[0006] Top cover unit;

[0007] a pole, which is inserted into the top cover unit and includes a base portion and a connecting portion, wherein the connecting portion protrudes along the axial direction of the base portion and is arranged on the end surface of the base portion, and a portion of the end surface of the base portion that is outside the coverage range of the connecting portion forms a stepped surface arranged around the connecting portion;

[0008] an upper plastic, at least partially sleeved on an outer peripheral side of the base portion, with a portion of the upper plastic being located on one side in a thickness direction of the top cover unit; and

[0009] A fixing member, a portion of which is located on the other side of the top cover unit in the thickness direction, and a joint arranged around the connecting portion is formed between the fixing member and the connecting portion, and the step surface abuts against the fixing member and covers the joint.

[0010] A battery comprises the above-mentioned end cover assembly.

[0011] An energy storage device comprises at least one of the above-mentioned batteries.

[0012] An electricity system includes the above-mentioned energy storage device.

[0013] The details of one or more embodiments of the present application are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the present application will become apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to better describe and illustrate the embodiments and / or examples of the applications disclosed herein, reference may be made to one or more of the accompanying drawings. The additional details or examples used to describe the accompanying drawings should not be considered to limit the scope of the disclosed applications, the presently described embodiments and / or examples, and any of the best modes currently understood for these applications.

[0015] FIG1 is a schematic diagram of the three-dimensional structure of an end cover assembly provided in one embodiment.

[0016] FIG2 is a schematic diagram of a partially exploded structure of the end cover assembly shown in FIG1 .

[0017] FIG3 is a schematic diagram of a three-dimensional cross-sectional structure of the cover plate in the top cover assembly shown in FIG1 .

[0018] FIG4 is a schematic diagram of a three-dimensional cross-sectional structure of the lower plastic of the top cover assembly shown in FIG1 .

[0019] FIG5 is a schematic perspective cross-sectional view of the upper plastic portion of the top cover assembly shown in FIG1 .

[0020] FIG6 is a schematic perspective cross-sectional view of the upper pole in the top cover assembly shown in FIG1 .

[0021] FIG7 is a schematic diagram of a partial planar cross-sectional structure of the end cover assembly shown in FIG1 .

[0022] FIG8 is a schematic diagram of a partial three-dimensional cross-sectional structure of the end cover assembly shown in FIG1 .

[0023] FIG9 is a schematic diagram of the three-dimensional structure of a battery provided in one embodiment.

[0024] FIG10 is an exploded schematic diagram of an energy storage device provided by an embodiment.

[0025] FIG11 is a schematic diagram of the planar structure of an electric power system provided in one embodiment. DETAILED DESCRIPTION

[0026] To make the above-mentioned objects, features, and advantages of the present application more readily apparent, specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth numerous specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0027] In the description of this application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0028] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, if the term "plurality" appears, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0029] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connected," "fixed," etc., should be interpreted broadly. For example, these terms may refer to fixed connections, removable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0030] In this application, unless otherwise expressly specified or limited, if a first feature is described as being "above" or "below" a second feature, or similar descriptions, this may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is described as being "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is described as being "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0031] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only embodiment.

[0032] Referring to Figures 1 and 2, an end cap assembly 10 provided in one embodiment of the present application is applied to a battery 20 (as shown in Figure 9). The battery 20 can be applied to an energy storage device 30. The energy storage device 30 can have the purpose of storing energy. The energy storage device 30 includes at least one battery 20. The end cap assembly 10 includes a top cap unit 100, an upper plastic 200, a fixing member 300, and a pole 400. The top cap unit 100 can serve as a carrier, so that the upper plastic 200 and the fixing member 300 are both arranged on the top cap unit 100, the pole 400 is sleeved in the upper plastic 200 and welded to the fixing member 300, and the pole 400 is passed through the top cap unit 100.

[0033] Referring to Figures 1, 2, and 3, in some embodiments, the top cover unit 100 includes a cover plate 110 and a lower plastic 120. The cover plate 110 and the lower plastic 120 are stacked one on another. The cover plate 110 can be made of aluminum, and the lower plastic 120 is obviously made of plastic. The cover plate 110 is provided with a first countersunk hole 111 and a through hole 112. The first countersunk hole 111 and the through hole 112 can be coaxially arranged and interconnected. The diameter of the first countersunk hole 111 is larger than that of the through hole 112. The first countersunk hole 111 is formed by recessing a predetermined depth from the surface of the cover plate 110 in the thickness direction away from the lower plastic 120. The through hole 112 is formed by recessing the middle portion of the bottom wall of the first countersunk hole 111. The through hole 112 extends to the surface of the cover plate 110 in the thickness direction near the lower plastic 120, so that the through hole 112 has an opening on this surface, that is, the through hole 112 penetrates the cover plate 110.

[0034] 1 , 2 and 4 , in some embodiments, the lower plastic 120 is provided with a second countersunk hole 121 and a mounting hole 122. The second countersunk hole 121 and the mounting hole 122 can be coaxially arranged and interconnected. The diameter of the second countersunk hole 121 is larger than that of the mounting hole 122. The second countersunk hole 121 is formed by a surface depression of a set depth away from the cover plate 110 in the thickness direction of the lower plastic 120. The mounting hole 122 is formed by a depression of the middle portion of the bottom wall of the second countersunk hole 121. The mounting hole 122 will extend to the surface of the lower plastic 120 in the thickness direction close to the cover plate 110, so that the mounting hole 122 has an opening on this surface, that is, the mounting hole 122 penetrates the lower plastic 120.

[0035] 7 and 8 , when the cover plate 110 and the lower plastic 120 are stacked on each other, the first countersunk hole 111, the through hole 112, the mounting hole 122, and the second countersunk hole 121 are arranged in sequence along the thickness direction of the entire end cap assembly 10. The first countersunk hole 111, the through hole 112, the mounting hole 122, and the second countersunk hole 121 are interconnected, so that the pole 400 can be simultaneously inserted into the first countersunk hole 111, the through hole 112, the mounting hole 122, and the second countersunk hole 121.

[0036] Referring to Figures 2 and 5, in some embodiments, the upper plastic 200 is made of a plastic material and includes a base ring 210, an outer sleeve 220, and an inner sleeve 230. The base ring 210 can be an annular structure and arranged horizontally, while the outer sleeve 220 and the inner sleeve 230 can both be cylindrical structures and arranged vertically. The inner sleeve 230 and the outer sleeve 220 are located on opposite sides of the base ring 210 in the thickness direction. The outer sleeve 220 is connected to the outer periphery of the base ring 210, so that the outer sleeve 220 is arranged around the base ring 210 and extends toward one side in the thickness direction of the base ring 210 by a set length. Obviously, the outer sleeve 220 protrudes from the base ring 210 by a set length. The inner sleeve 230 is connected to the inner periphery of the base ring 210 so that the base ring 210 is arranged around the inner sleeve 230. The inner sleeve 230 extends a set length toward the other side in the thickness direction of the base ring 210. Obviously, the inner sleeve 230 also protrudes a set length relative to the base ring 210.

[0037] 5 , 7 , and 8 , during the installation of the upper plastic 200, the inner sleeve 230 can be inserted into the through-hole 112, forming an interference fit with the through-hole 112. The base ring 210 is at least partially received in the first counterbore 111, and the base ring 210 abuts against the unrecessed edge of the bottom wall of the first counterbore 111. That is, the base ring 210 overlaps the bottom wall of the first counterbore 111, so that the bottom wall of the first counterbore 111 effectively limits the entire upper plastic 200 in the vertical direction. Furthermore, the sidewalls of the first counterbore 111 also effectively limit the upper plastic 200 in the horizontal direction, thereby improving the installation efficiency and accuracy of the upper plastic 200. It is understood that the vertical direction can also be understood as the thickness direction of the entire end cap assembly 10. When the inner sleeve 230 is engaged with the through-hole 112, the free end of the inner sleeve 230 can also extend into the mounting hole 122 of the lower plastic 120. The diameter of the mounting hole 122 is larger than the outer diameter of the inner sleeve 230, resulting in a larger gap between the inner sleeve 230 and the sidewall of the mounting hole 122. Obviously, after the upper plastic 200 is installed, at least a portion of the outer sleeve 220 can be located outside the first counterbore 111. The portion of the outer sleeve 220 located outside the first counterbore 111 can be understood as the portion of the outer sleeve 220 located on one side of the top cover unit 100 in the thickness direction. In some embodiments, the end of the inner sleeve 230 away from the base ring 210 is a free end. This free end is provided with an outer chamfer 231, which can be an outer rounded corner. The angle of the outer chamfer 231 can range from 10° to 45°. For example, the specific angle of the outer chamfer 231 can be 10°, 35°, or 45°. The provision of the outer chamfer 231, on the one hand, serves as a guide during the mating process between the inner sleeve 230 and the through-hole 112, allowing the inner sleeve 230 to be smoothly inserted into and mated with the through-hole 112. This reduces the difficulty of assembling the upper plastic 200, thereby improving the efficiency of assembling the upper plastic 200 on the cover plate 110. On the other hand, it reduces the scraping force generated between the inner sleeve 230 and the cover plate 110 during assembly, preventing the inner sleeve 230 from generating a large amount of plastic debris due to the scraping force, preventing the debris from affecting the normal function of the end cap assembly 10 and the battery 20, and also preventing the structural strength of the inner sleeve 230 from being affected by the scraping.

[0038] 5 , 7 and 8 , in some embodiments, the fixing member 300 may also be an annular structure and made of a metal material. The fixing member 300 is at least partially accommodated in the second countersunk hole 121 of the lower plastic 120 , so that a portion of the fixing member 300 is located on the other side of the top cover unit 100 opposite to the upper plastic 200 in the thickness direction. The fixing member 300 abuts against the non-recessed edge portion of the bottom wall of the second countersunk hole 121 , that is, the fixing member 300 is superimposed on the bottom wall of the second countersunk hole 121 , so that the bottom wall of the second countersunk hole 121 plays a good limiting role in the vertical direction for the entire fixing member 300 , and the side wall surface of the second countersunk hole 121 can also play a good limiting role in the horizontal direction for the fixing member 300 , thereby improving the installation efficiency and installation accuracy of the fixing member 300 . When the fixing member 300 is received in the second countersunk hole 121 , a portion of the lower plastic 120 is overlapped between the fixing member 300 and the cover 110 , and the fixing member 300 and the cover 110 partially cover the opposite ends of the mounting hole 122 of the lower plastic 120 .

[0039] Referring to Figures 6, 7, and 8, in some embodiments, the terminal post 400 includes a base portion 410 and a connecting portion 420. The base portion 410 and the connecting portion 420 may be coaxially arranged. The cross-section of the connecting portion 420 is smaller than that of the base portion 410. The connecting portion 420 protrudes axially from the end surface of the base portion 410. The edge of the end surface is not covered by the connecting portion 420, that is, it is located outside the coverage of the connecting portion 420, forming a stepped surface 411 surrounding the connecting portion 420. The upper plastic 200 is sleeved on the outer periphery of the base portion 410, and the fixing member 300 is sleeved outside the connecting portion 420, with the fixing member 300 abutting the stepped surface 411.

[0040] The base portion 410 includes a first segment 412 and a second segment 413, which are coaxially arranged. The cross-section of the first segment 412 is larger than that of the second segment 413 and is also perpendicular to the axial direction of the terminal 400. One end of the second segment 413 is connected to the first segment 412, and the other end of the second segment 413 is connected to the connecting portion 420, so that the second segment 413 is connected between the first segment 412 and the connecting portion 420. The stepped surface 411 is located on the second segment 413. When the terminal 400 is assembled with the upper plastic 200, the outer sleeve 220 of the upper plastic 200 is sleeved on the first segment 412, and the inner sleeve 230 of the upper plastic 200 is sleeved on the second segment 413. The base ring 210 of the upper plastic 200 overlaps with the first segment 412 along the thickness direction of the end cap assembly 10. Therefore, the base ring 210 effectively limits the position of the pole 400 in the vertical direction, while the inner sleeve 230 and outer sleeve 220 effectively limit the position of the pole 400 in the horizontal direction. This improves the assembly efficiency and precision between the pole 400 and the upper plastic 200. After the upper plastic 200 and the pole 400 are assembled, the base ring 210 of the upper plastic 200 is superimposed between the cover plate 110 and the first segment 412 of the pole 400.

[0041] When the fixing member 300 is sleeved on the outer periphery of the connecting portion 420, an annular joint 310 exists between the fixing member 300 and the connecting portion 420. Obviously, the joint 310 surrounds the connecting portion 420. When the fixing member 300 and the connecting portion 420 need to be welded together, laser welding can be used. Laser irradiation is applied to the joint 310, causing a molten liquid to form in the fixing member 300 and the connecting portion 420 near the joint 310. After cooling, the molten liquid solidifies to form a weld layer, thereby welding the fixing member 300 and the connecting portion 420 to each other. Since the fixing member 300 abuts the stepped surface 411 of the pole 400, the installation accuracy of the fixing member 300 can be improved, and the accuracy requirements of the welding fixture during the welding process of the fixing member 300 can be reduced.

[0042] If a design pattern is adopted in which the cross-sections of the second segment 413 and the connecting portion 420 are equal, the step surface 411 is eliminated at the junction of the second segment 413 and the connecting portion 420. Since the inner sleeve 230 of the upper plastic 200 is mounted on the second segment 413 and the fixing member 300 is mounted on the connecting portion 420, the inner sleeve 230 is positioned directly above the joint 310 between the fixing member 300 and the connecting portion 420. This means that the vertical projection of the inner sleeve 230 covers the joint 310 between the fixing member 300 and the connecting portion 420. During laser welding, the laser will pass through the joint 310 and irradiate the inner sleeve 230 of the upper plastic 200, causing partial burns and functional failure of the inner sleeve 230. This will impair the normal function of the end cap assembly 10 and ultimately affect the reliability of the entire end cap assembly 10.

[0043] In the end cap assembly 10 of the aforementioned embodiment, since the cross-section of the second segment 413 is larger than that of the connecting portion 420, the second segment 413 has a stepped surface 411 surrounding the connecting portion 420. This stepped surface 411 abuts against the fixing member 300 and covers the joint 310. Since the inner sleeve 230 of the upper plastic 200 is positioned around the outer periphery of the second segment 413 and the fixing member 300 is positioned around the outer periphery of the connecting portion 420, the stepped surface 411 covers the joint 310. During laser welding, the laser beam passes through the joint 310 and strikes the stepped surface 411. However, the stepped surface 411 blocks the laser beam from striking the inner sleeve 230, preventing partial burns on the inner sleeve 230 and potentially causing functional failure. This prevents the normal function of the end cap assembly 10 from being compromised, ultimately improving the reliability of the entire end cap assembly 10. Of course, there is a horizontal distance between the inner sleeve 230 and the joint 310 between the fixing member 300 and the connecting portion 420 , thereby maintaining a certain offset relationship, effectively preventing the inner sleeve 230 from being located directly above the joint 310 , and further preventing the laser from irradiating the inner sleeve 230 .

[0044] Referring to Figures 6, 7, and 8, in some embodiments, the pole 400 further includes a boss portion 430. The boss portion 430 and the connecting portion 420 can be coaxially arranged. The cross-sectional dimensions of the boss portion 430 are smaller than those of the connecting portion 420. The above cross-sectional dimensions are all perpendicular to the axial direction of the pole 400. The boss portion 430 is provided protrudingly on the end surface of the connecting portion 420 away from the base portion 410. Apparently, the boss portion 430 and the connecting portion 420 are connected in a stepped structure. The end surface of the boss portion 430 away from the connecting portion 420 is used for welding a connecting piece. The end surfaces of the connecting portion 420 and the fixing member 300 located near the boss portion 430 can be flush with each other. This allows the molten liquid during the laser welding process to simultaneously cover the edge portions of both end surfaces near the joint 310, thereby enhancing the connection strength between the connecting portion 420 and the fixing member 300.

[0045] If a design mode is adopted in which the connecting piece is welded directly to the end face of the connecting portion 420 away from the base portion 410 without providing the boss portion 430, after the fixing member 300 and the connecting portion 420 are welded, the welding layer will form a number of protrusions on the end face of the connecting portion 420 away from the base portion 410. The protrusions will support the connecting piece, making it impossible for the connecting piece to be in close contact with the end face of the connecting portion 420. Therefore, during the welding process between the connecting piece and the connecting portion 420, since the connecting piece cannot be in close contact with the end face of the connecting portion 420, the weld width and depth of the connecting piece will be reduced, affecting the connection strength after welding the connecting piece and the connecting portion 420. It will also reduce the contact area between the connecting piece and the connecting portion 420, resulting in a decrease in the flow capacity. When the end cap assembly 10 is applied to the battery 20, it will also cause the battery 20 to heat up severely during the charging and discharging process.

[0046] In the end cap assembly 10 of the aforementioned embodiment, by providing a protruding boss portion 430 on the end surface of the connecting portion 420, the connection piece is effectively prevented from being welded to the end surface of the connecting portion 420, thereby shifting the welding position of the connection piece from the end surface of the connecting portion 420 to the end surface of the boss portion 430. Therefore, the connection piece located on the end surface of the boss portion 430 maintains a certain distance from the protrusion of the welding layer on the end surface of the connecting portion 420, preventing the protrusion of the welding layer from supporting the connection piece. This eliminates interference caused by the protrusion of the welding layer and ensures that the connection piece always closely adheres to the protruding end surface. Therefore, during the welding process of the connection piece and the boss portion 430, the connection piece's weld penetration width and depth are effectively increased, thereby improving the post-weld connection strength between the connection piece and the boss portion 430. This also increases the contact area between the connection piece and the boss portion 430, thereby enhancing the current carrying capacity. When the end cap assembly 10 is applied to the battery 20, it can effectively reduce the heat accumulated in the battery 20 during the charging and discharging process.

[0047] Referring to Figures 6, 7, and 8, in some embodiments, the length of the boss portion 430 ranges from 0.1 mm to 1 mm. (mm means millimeter in Chinese.) The length of the boss portion 430 can be understood as the height of the boss portion 430 protruding from the connecting portion 420. For example, the specific length of the boss portion 430 can be 0.1 mm, 0.5 mm, or 1 mm. This ensures that the connecting piece attached to the end surface of the boss portion 430 maintains a reasonable distance from the protrusion of the welding layer, effectively eliminating the supporting and interference effects of the protrusion of the welding layer on the connecting piece. The cross-sectional dimension of the boss portion 430 gradually decreases from the end closest to the connecting portion 420 to the end farther away from the connecting portion 420, thus giving the boss portion 430 a certain degree of taper. By making the boss portion 430 have a certain taper, on the one hand, it is easier to demold the formed pole 400 from the mold, avoiding the formation of scratches on the boss portion 430 due to the scraping force of the mold; on the other hand, the pole 400 has a larger contact area with the punch of the mold during the molding process, which can reduce the wear of the punch, thereby improving the consistency of the pole 400 products produced by the mold, and ultimately improving the quality of the pole 400.

[0048] For example, the boss portion 430 can be truncated cone-shaped. Obviously, the end of the truncated cone-shaped boss portion 430 with the largest cross-sectional dimension is directly connected to the connecting portion 420, and the connecting piece is welded to the end of the truncated cone-shaped boss portion 430 with the smallest cross-sectional dimension. The angle α between the generatrix of the truncated cone-shaped boss portion 430 and the centerline axis of the boss portion 430 ranges from 5° to 45°. For example, the specific value of the angle α can be 5°, 35°, or 45°. The generatrix can be understood as the intersection of a longitudinal section passing through the centerline of the boss portion 430 and the outer side surface of the boss portion 430.

[0049] 6, 7, and 8, in some embodiments, the end cap assembly 10 further includes a seal 500. The seal 500 is at least partially received within the mounting hole 122 of the lower plastic 120. The seal 500 surrounds the inner sleeve 230 of the upper plastic 200 and abuts between the cover plate 110 and the fixing member 300. The provision of the seal 500 enhances the sealing capability of the end cap assembly 10, preventing external liquids and dust from intruding into the battery 20 through the cover plate 110 assembly, and also preventing the electrolyte in the battery 20 from leaking from the end cap assembly 10.

[0050] Given the presence of a stepped surface 411 between the base portion 410 and the connecting portion 420, when the fixing member 300 abuts the stepped surface 411, the compressed dimensions of the seal 500 remain constant. Specifically, the distance between the first segment 412 and the fixing member 300 is denoted as the first dimension, the thickness of the base ring 210 of the upper plastic 200 is denoted as the second dimension, and the thickness of the overlapped portion of the cover plate 110 and the base ring 210 is denoted as the third dimension. The first, second, and third dimensions can form a dimensional chain. Therefore, the compressed dimensions of the seal 500 are equal to the first dimension minus the difference between the second and third dimensions. Therefore, the compressed dimensions of the seal 500 are only dependent on the first, second, and third dimensions. This eliminates the influence of other dimensions and reduces the number of dimensions involved in the dimensional chain. This can also be understood as reducing the factors that influence the compressed dimensions of the seal 500. Furthermore, since the cover plate 110, upper plastic 200, and terminal 400 are all molded, the accuracy of the first, second, and third dimensions can be guaranteed.

[0051] Therefore, by reducing the total number of participating dimensions in the dimension chain that affect the size of the seal 500 after compression and ensuring the processing accuracy of each participating dimension in the dimension chain, the dependence on the fixture can be reduced or even eliminated, so that the size of the seal 500 after compression remains constant, that is, the stability and consistency of the compression amount of the seal 500 are improved, thereby ensuring the sealing performance of the seal 500 and improving the sealing reliability of the end cover assembly 10.

[0052] Referring to Figures 9, 10 and 11, the present application also provides a battery 20, an energy storage device 30 and an electric system 40. The battery 20 includes a case 21, a battery cell and the above-mentioned end cover assembly 10. The battery cell is stored in the case 21, and the end cover assembly 10 is covered on the case 21. By providing the above-mentioned end cover assembly 10, the reliability of the battery 20 during operation can be improved. The energy storage device 30 includes at least one battery 20. For example, the energy storage device 30 may include multiple batteries 20, so that the energy storage device 30 can be used for energy storage. The electric system 40 includes the above-mentioned energy storage device 30. The energy storage device 30 can be, for example, a battery pack, a battery cluster, an energy storage cabinet, etc. The electric system 40 can include a load and an energy storage device 30. The energy storage device 30 supplies power to the load. The electric system 40 can be, for example, an electric car.

[0053] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0054] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. An end cap assembly, characterized in that: include: Top cover unit; A pole, which is inserted into the top cover unit and comprises a base portion and a connecting portion, wherein the connecting portion is arranged on the end surface of the base portion and protrudes along the axial direction of the base portion, and a portion of the end surface of the base portion that is outside the coverage of the connecting portion forms a step surface arranged around the connecting portion; An upper plastic is at least partially sleeved on the outer peripheral side of the base portion, and a portion of the upper plastic is located on one side in the thickness direction of the top cover unit; and A fixing member, a part of which is located on the other side of the top cover unit in the thickness direction, and a joint arranged around the connecting portion is formed between the fixing member and the connecting portion, and the step surface abuts against the fixing member and covers the joint.

2. The end cap assembly according to claim 1, characterized in that: The pole also includes a boss portion connected to the connection portion, the cross section of the boss portion perpendicular to the axial direction of the pole is smaller than the cross section of the connection portion perpendicular to the axial direction of the pole, and the boss portion protrudes from one end of the connection portion away from the base portion.

3. The end cap assembly according to claim 2, characterized in that: The length of the boss portion ranges from 0.1 mm to 1 mm.

4. The end cap assembly according to claim 3, characterized in that: The length of the boss portion is 0.1 mm, 0.5 mm or 1 mm.

5. The end cap assembly according to claim 2, characterized in that: From an end close to the connection portion to an end away from the connection portion, a cross-sectional dimension of the boss portion perpendicular to the axial direction of the pole gradually decreases.

6. The end cap assembly according to claim 5, characterized in that: The boss portion is in a truncated cone shape, and the angle between the generatrix of the boss portion and the center axis of the boss portion ranges from 5° to 45°.

7. The end cap assembly according to claim 6, characterized in that: The angle between the generatrix of the boss portion and the center axis of the boss portion is 5°, 35° or 45°.

8. The end cap assembly according to claim 2, characterized in that: Along the axial direction of the pole, end surfaces of the connecting portion and the fixing member disposed close to the boss portion are flush with each other.

9. The end cap assembly according to claim 1, characterized in that: The base portion includes a first segment and a second segment that are coaxially arranged, a cross section of the first segment along a direction perpendicular to the axial direction of the pole is larger than a cross section of the second segment along a direction perpendicular to the axial direction of the pole, and the step surface is located in the second segment; the upper plastic includes a base ring, an outer sleeve and an inner sleeve, the inner sleeve and the outer sleeve are located on opposite sides of the base ring in a thickness direction, the outer sleeve is connected to the outer periphery of the base ring, and the inner sleeve is connected to the inner periphery of the base ring; the first segment is superimposed on the base ring and sleeved in the outer sleeve, the inner sleeve is penetrated in the top cover unit and sleeved on the outer peripheral side of the second segment, and the base ring and the top cover unit are superimposed on each other.

10. The end cap assembly according to claim 9, characterized in that: It also includes a sealing member, the top cover unit includes a cover plate and a lower plastic, the cover plate is stacked between the lower plastic and the base ring, the fixing member is stacked on the side of the lower plastic away from the cover plate in the thickness direction, the lower plastic is provided with a mounting hole, the sealing member is at least partially accommodated in the mounting hole, and the sealing member is arranged around the inner sleeve and abuts between the cover plate and the fixing member.

11. The end cap assembly according to claim 9, characterized in that: A first countersunk hole and a second countersunk hole are respectively formed on two surfaces facing opposite to each other in the thickness direction of the top cover unit, the base ring cooperates with the first countersunk hole, and the fixing piece cooperates with the second countersunk hole.

12. The end cap assembly according to claim 11, characterized in that A through hole is formed on the bottom wall surface of the first countersunk hole, and the inner sleeve is interference-fitted with the through hole.

13. The end cap assembly according to claim 12, characterized in that: A mounting hole is formed on the bottom wall of the second countersunk hole. The mounting hole is communicated with the through hole. The inner sleeve extends into the mounting hole. There is a gap between the inner sleeve and the side wall of the mounting hole.

14. The end cap assembly according to claim 10, wherein: The cover plate, the upper plastic and the pole are all formed by a mold.

15. The end cap assembly according to claim 1, wherein: An end of the upper plastic close to the connecting portion is provided with an outer chamfer, and the angle of the outer chamfer is 10° to 45°.

16. The end cap assembly according to claim 15, characterized in that The value of the outer chamfer is 10°, 35° or 45°.

17. The end cap assembly according to claim 1, wherein: The fixing piece is connected to the connecting portion by laser welding.

18. A battery, characterized in that: An end cap assembly comprising the end cap assembly of any one of claims 1 to 17.

19. An energy storage device, characterized in that: Comprising at least one battery as claimed in claim 18.

20. An electricity system, characterized in that: Comprising the energy storage device as claimed in claim 19.

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