End cover assembly and manufacturing method therefor, energy storage device, and electric apparatus

Abstract

The present application discloses an end cover assembly and a manufacturing method therefor, an energy storage device, and an electric apparatus. The end cover assembly comprises an end cover, a lower plastic, poles, and sealing rings. The end cover is provided with through holes. The lower plastic comprises pole through holes. The lower plastic and the end cover are stacked in the thickness direction of the end cover assembly. Each through hole is in communication with the corresponding pole through hole. Each pole comprises a pole body, a flange, and a folding portion. The folding portion and the flange are opposite to each other and spaced apart from each other in the height direction of the pole. The pole body comprises a mounting surface facing away from the flange. The folding portion protrudes from the periphery of one end portion of the pole body and surrounds the mounting surface. The folding portion comprises an exterior surface connected to the mounting surface. A crease is provided between the exterior surface and the mounting surface. The exterior surface is flush with the mounting surface, or, in the direction from the folding portion to the flange, the mounting surface protrudes from the exterior surface. Each sealing ring is sleeved on the outer periphery of the corresponding pole and passes through the corresponding through hole and the corresponding pole through hole together with the pole. The end cover part on the periphery of the through hole is located between the flange and the folding portion. The flange, the lower plastic, the end cover, and the folding portion jointly clamp the sealing ring.

Description

End cap assembly and its manufacturing method, energy storage device and electrical equipment

[0001] This application claims priority to Chinese Patent Application No. 2024117546492, filed on December 2, 2024, entitled “End Cap Assembly and Method of Manufacturing Thereof, Energy Storage Device and Electrical Equipment”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of energy storage technology, and in particular to an end cap assembly and its manufacturing method, an energy storage device and an electrical device. Background Technology

[0003] With the development of secondary energy storage technology and the increase in demand, people are gradually increasing their requirements for the reliability of energy storage devices, especially the reliability of end cap assemblies. The sealing structure in existing end cap assemblies is complex. For example, the end cap assembly includes upper plastic, lower plastic, and sealing rings and other structural components used for sealing. There are many assembly gaps between them, and the sealing performance decreases in low-temperature environments, and even the problem of sealing failure may occur, which greatly reduces the reliability of the end cap assembly. Summary of the Invention

[0004] This application provides an end cap assembly and its manufacturing method, an energy storage device, and an electrical device, which can improve the reliability of the end cap assembly.

[0005] This application provides an end cap assembly, the end cap comprising:

[0006] An end cap, wherein the end cap has a through hole that penetrates both surfaces of the end cap in the thickness direction.

[0007] The lower plastic includes an electrode through-hole, which penetrates two surfaces of the lower plastic in the thickness direction. The lower plastic and the end cap are stacked along the thickness direction of the end cap assembly, and the through-hole communicates with the electrode through-hole.

[0008] An electrode post includes an electrode post body and a flange. The flange is connected to one end of the electrode post body in the height direction. The electrode post body includes a mounting surface facing away from the flange. The electrode post also includes a folded portion, which protrudes from the periphery of one end of the electrode post body and surrounds the mounting surface. The folded portion and the flange are opposite to and spaced apart along the height direction of the electrode post. The folded portion includes an outer surface facing away from the flange and connected to the mounting surface. A crease exists between the outer surface and the mounting surface. The outer surface is flush with the mounting surface, or, along the direction from the folded portion to the flange, the mounting surface protrudes from the outer surface.

[0009] A sealing ring is fitted around the outer periphery of the pole body and passes through the through hole and the pole through hole together with the pole. The end cap portion around the through hole is located between the flange and the folded part. The flange, the lower plastic, the end cap and the folded part together clamp the sealing ring, and the end cap, the lower plastic and the pole compress the sealing ring.

[0010] In one embodiment, this application provides a method for manufacturing an end cap assembly, the method comprising:

[0011] Provide a sealing ring before assembly, and provide the extension direction of the first segment and the extension direction of the second segment of the sealing ring before assembly;

[0012] A pre-assembly pole is provided. The mounting surface of the pre-assembly pole body has a protrusion. The pre-assembly pole includes a folded portion base. The folded portion base is arranged around the periphery of the pole body and protrudes from the mounting surface of the pole body. A groove is formed between the folded portion base and the protrusion. The folded portion includes an inner ring surface. The inner ring surface is connected to the mounting surface and is arranged at an angle to the mounting surface. The extending direction of the folded portion base is the same as the axial direction of the pre-assembly pole.

[0013] The lower plastic and the end cap are stacked together, and the through hole of the pole post of the lower plastic and the through hole of the end cap are coaxial and connected.

[0014] Before assembly, the pole is inserted through the sealing ring before assembly, and passes through the pole through hole and the through hole in sequence with the sealing ring before assembly. The flange protrudes from the lower plastic. The third section is clamped between the end cap and the flange. The folded part base and the first section protrude from the end cap. The first section extends in the same direction as the folded part base. The second section connects between the end cap and the pole body.

[0015] The folding base is flipped away from the end cap, and the first segment is pressed against the end cap, so that the folding base forms the folding portion, the inner ring surface forms the outer surface, the folding portion and the end cap hold the first segment, and the outer surface is flush with the mounting surface.

[0016] This application provides an energy storage device, which includes a housing, an electrode assembly, and an end cap assembly. The electrode assembly is mounted on the housing, and the end cap assembly is mounted on one end of the electrode assembly and seals the housing.

[0017] This application provides an electrical device, which includes the energy storage device and supplies power to the electrical device.

[0018] In related technologies, the sealing structure in end cap assemblies is complex. For example, end cap assemblies include upper and lower plastic components, as well as sealing rings and other sealing structures. The sealing performance of these components deteriorates at low temperatures, and they are prone to failure, reducing the reliability of the end cap assembly. For instance, existing end cap assemblies typically use fluororubber for sealing. Fluororubber is prone to embrittlement at low temperatures (-40°C), causing the end cap assembly to fail to seal and resulting in malfunctions in the energy storage device.

[0019] In this embodiment, the end cap assembly has a simple structure, requiring only a first sealing ring and a second sealing ring as sealing components. The sealing rings effectively block the gaps between the end cap, the lower plastic, and the electrode post, and can also mate with the end cap as the upper plastic, reducing assembly gaps and improving sealing performance. Furthermore, this embodiment eliminates the need for an upper plastic, saving manufacturing costs and simplifying the structure. Both the first and second sealing rings are made of low-temperature resistant and electrolyte-resistant rubber-synthetic materials, ensuring good sealing performance even at low temperatures and improving the reliability of the end cap assembly. Attached Figure Description

[0020] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 is an application scenario diagram of the energy storage device provided in the embodiment of this application;

[0022] Figure 2 is a schematic diagram of the energy storage device shown in Figure 1;

[0023] Figure 3 is a structural schematic diagram of the first embodiment of the end cap assembly of the energy storage device shown in Figure 2;

[0024] Figure 4 is an exploded view of the end cap assembly shown in Figure 3;

[0025] Figure 5 is an exploded view of the end cap assembly shown in Figure 4 from another angle;

[0026] Figure 6 is a cross-sectional view of the first and second sealing rings of the end cap assembly shown in Figure 4;

[0027] Figure 7 is a cross-sectional view of the first pole post and the second pole post of the end cap assembly shown in Figure 4 in a first embodiment;

[0028] Figure 8 is a cross-sectional view of the end cap assembly shown in Figure 3;

[0029] Figure 9a is a schematic diagram of the structure of the first pole post, the first sealing ring, the end cap and the lower plastic before assembly of the end cap assembly shown in Figure 3.

[0030] Figure 9b is a schematic diagram of the assembly process of the end cap assembly shown in Figure 9a, showing the first pole post, the first sealing ring, the end cap, and the lower plastic part fitting together.

[0031] Figure 9c is a schematic diagram of the assembly of the end cap assembly shown in Figure 9b, showing the first pole post, the first sealing ring, the end cap, and the lower plastic part fitting together.

[0032] Figure 10 is an exploded view of a second embodiment of the end cap assembly of the energy storage device shown in Figure 2;

[0033] Figure 11 is an exploded view of the end cap assembly shown in Figure 10 from another angle;

[0034] Figure 12 is a cross-sectional view of a second embodiment of the first and second poles of the end cap assembly shown in Figure 10;

[0035] Figure 13 is a cross-sectional view of the end cap assembly shown in Figure 10.

[0036] Figure 14 is an exploded view of part of the structure of the end cap assembly shown in Figure 13;

[0037] Figure 15a is a schematic diagram of the structure of the first pole post with the first sealing ring and the second pole post with the second sealing ring before assembly of the end cap assembly shown in Figure 14, and the end cap and the lower plastic.

[0038] Figure 15b is a schematic diagram of the assembly of the end cap assembly shown in Figure 15a, in which the first pole post with the first sealing ring and the second pole post with the second sealing ring fit together with the end cap and the lower plastic.

[0039] Figure 16 is a partial structural exploded view of the end cap assembly shown in Figure 10.

[0040] The terms corresponding to the reference numerals in the figures are as follows: Energy storage device 1000, end cap assembly 100, outer shell 200, opening 201, end cap 10, first surface 11, second surface 12, first sealing groove 13, first groove bottom wall 131, first groove peripheral wall 132, second sealing groove 14, second groove bottom wall 141, second groove peripheral wall 142, first through hole 15, second through hole 16, limiting groove 17, lower plastic 20, top surface 21, bottom surface 22, first clearance groove 23, third groove peripheral wall 231, third... 232, bottom wall of the groove; 24, second clearance groove; 241, peripheral wall of the fourth groove; 242, bottom wall of the fourth groove; 25, through hole of the first pole post; 26, through hole of the second pole post; 27, limiting post; 30, first pole post; 31, body of the first pole post; 311, first mounting surface; 312, first peripheral side surface; 313, first protrusion; 314, first welding surface; 32, first flange; 321, first connecting surface; 322, first flange surface; 323, first step; 324, first assembly surface; 325, first folding part; 33, first... Sealing surface 331, first outer surface 332, first folded portion base 33a, first groove 35, second pole post 40, second pole post body 41, second mounting surface 411, second peripheral side surface 412, second protrusion 413, second welding surface 414, second flange 42, second connecting surface 421, second flange surface 422, second step 423, second step surface 424, second assembly surface 425, second folded portion 43, second sealing surface 431, second outer surface 432, second folded portion base 43a, second outer ring surface 441, second inner ring surface 442, second groove 45, first sealing ring 50, first sealing hole 50a, first segment 51, second segment 52, third segment 53, second sealing ring 60, second sealing hole 60a, fourth segment 61, fifth segment 62, sixth segment 63, first gap H1, second gap H2, energy storage system 5000, first power conversion device 4100, second power conversion device 4200, first electrical equipment 3000, second electrical equipment 2000. Detailed Implementation

[0041] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0042] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly specified. Furthermore, the terms "same," "equal," or "parallel" used below are all allowed to have certain tolerances.

[0043] It should be noted that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include at least one of those features.

[0044] Because the energy we need is highly time- and space-dependent, in order to utilize energy rationally and improve energy efficiency, it is necessary to store one form of energy in the same way or by converting it into another, and then release it in a specific energy form according to future application needs. As we all know, to achieve the grand goal of carbon neutrality, the main way to generate green electricity is to develop green energy sources such as photovoltaics and wind power to replace fossil fuels. Currently, the generation of green electricity generally relies on photovoltaics, wind power, and hydropower. However, wind and solar energy generally suffer from strong intermittency and large fluctuations, which can cause grid instability, insufficient electricity during peak demand periods, and excessive electricity during off-peak periods. Unstable voltage can also damage the power grid. Therefore, insufficient electricity demand or insufficient grid capacity may lead to the problem of "wind and solar curtailment." Solving these problems requires energy storage. Energy storage involves converting electrical energy into other forms of energy through physical or chemical means and storing it. When needed, the stored energy is converted back into electrical energy and released. Simply put, energy storage is like a large "power bank". When there is sufficient solar and wind power, electrical energy is stored and the stored power is released when needed.

[0045] Taking electrochemical energy storage as an example, this application provides an energy storage device 1000. The energy storage device 1000 is equipped with a set of chemical batteries. It mainly uses the chemical elements in the chemical batteries as energy storage medium. The charging and discharging process is accompanied by the chemical reaction or change of the energy storage medium. Simply put, the electrical energy generated by wind and solar energy is stored in the chemical batteries. When the use of external electrical energy reaches its peak, the stored electrical energy is released for use, or transferred to places with a shortage of electricity for use.

[0046] Current energy storage applications are quite widespread, including energy storage on the (wind and solar) power generation side, grid-side energy storage, base station-side energy storage, and user-side energy storage. The corresponding energy storage devices include:

[0047] (1) Large energy storage containers used in grid-side energy storage scenarios can serve as high-quality active and reactive power regulation power sources in the grid, enabling load matching of electrical energy in time and space, enhancing the absorption capacity of renewable energy, and playing a significant role in grid system backup, alleviating peak load power supply pressure, and peak regulation and frequency regulation.

[0048] (2) Small and medium-sized energy storage cabinets used in industrial and commercial energy storage scenarios (banks, shopping malls, etc.) on the user side mainly operate under the "peak shaving and valley filling" mode.

[0049] Because there are significant price differences in electricity during peak and off-peak periods depending on electricity demand, users with energy storage devices typically charge the storage cabinets / boxes during off-peak periods to reduce costs, and then release the electricity from the storage devices for use during peak periods, in order to save on electricity bills.

[0050] It should be noted that the aforementioned energy storage containers, small and medium-sized energy storage cabinets, and household small energy storage boxes, which contain energy storage devices of 1000, can be understood as electrical equipment.

[0051] Please refer to Figure 1, which is an application scenario diagram of the energy storage device provided in the embodiments of this application.

[0052] The energy storage device 1000 provided in this application embodiment is applied to an energy storage system 5000. The energy storage system 5000 includes a first power conversion device 4100 (photovoltaic panel), a second power conversion device 4200 (wind turbine), a first electrical device 3000 (grid), a second electrical device 2000 (base station), and the energy storage device 1000. The energy storage system 5000 also includes an energy storage cabinet, in which the energy storage device 1000 is installed. The energy storage cabinet can be installed outdoors. Specifically, the first power conversion device 4100 can convert solar energy into electrical energy during periods of low electricity prices. The energy storage device 1000 stores this electrical energy and supplies it to the first electrical device 3000 or the second electrical device 2000 during peak electricity demand periods, or provides power when the first electrical device 3000 or the second electrical device 2000 experiences a power outage. The second power conversion device 4200 can convert wind energy into electrical energy. The energy storage device 1000 is used to store the electrical energy and supply it to the first electrical device 3000 or the second electrical device 2000 during peak electricity consumption, or to supply power when the first electrical device 3000 or the second electrical device 2000 experiences a power outage. The electrical energy can be transmitted using high-voltage cables.

[0053] It should be noted that the aforementioned first electrical device 3000, second electrical device 2000, and other devices including the energy storage device 1000 can be understood as electrical devices. The energy storage device 1000 supplies power to the electrical devices.

[0054] The number of energy storage devices 1000 can be multiple, and the multiple energy storage devices 1000 can be connected in series or in parallel. In this embodiment, "multiple" means two or more.

[0055] It is understood that the energy storage device 1000 may include, but is not limited to, single-cell batteries, battery modules, battery packs, and battery systems. The actual application form of the energy storage device 1000 provided in this application embodiment may be, but is not limited to, the listed products, and may also be other application forms. For example, the energy storage device 1000 may be a nickel-metal hydride battery, a nickel-cadmium battery, a lead-acid (or lead-acid) battery, a lithium-ion battery, a polymer lithium-ion battery, or other rechargeable batteries. When the energy storage device 1000 is a single-cell battery, it may be a cylindrical battery, a prismatic battery, or a battery of other shapes. In this embodiment, the energy storage device 1000 is described using a prismatic battery as an example. The prismatic battery is a rechargeable battery.

[0056] Please refer to Figure 2, which is a schematic diagram of the energy storage device shown in Figure 1.

[0057] For ease of description, the width of the energy storage device 1000 is defined as the X-axis, the length as the Y-axis, and the height as the Z-axis. The X-axis, Y-axis, and Z-axis are all perpendicular to each other.

[0058] The directional terms such as "upper," "top," "lower," and "bottom" used in the description of the embodiments in this application are based on the orientation shown in Figure 2 of the specification and do not constitute a limitation on the energy storage device 1000 in actual application scenarios. Specifically, the positive direction toward the Z-axis is considered the top or above of the energy storage device 1000, and the negative direction toward the Z-axis is considered the bottom or below of the energy storage device 1000.

[0059] In this embodiment, the energy storage device 1000 includes an end cap assembly 100, a housing 200, and an electrode assembly (not shown). The housing 200 has an opening 201 and a receiving cavity (not shown). The receiving cavity communicates with the opening 201. The electrode assembly is housed within the receiving cavity of the housing 200. The end cap assembly 100 is mounted on one end of the electrode assembly and seals the opening 201 of the housing 200 to isolate the internal environment of the energy storage device 1000 from the external environment. In this embodiment, the housing 200 is a rectangular shell.

[0060] Please refer to Figures 3, 4 and 5. Figure 3 is a structural schematic diagram of the end cap assembly of the energy storage device shown in Figure 2 according to a first embodiment. Figure 4 is an exploded schematic diagram of the end cap assembly shown in Figure 3. Figure 5 is an exploded schematic diagram of the end cap assembly shown in Figure 4 from another angle.

[0061] The end cap assembly 100 includes an end cap 10, a lower plastic part 20, a first electrode post 30, a second electrode post 40, a first sealing ring 50, and a second sealing ring 60. The end cap 10 and the lower plastic part 20 are stacked along the Z-axis. The first electrode post 30 and the second electrode post 40 are located at opposite ends along the length direction (Y-axis direction) of the end cap assembly 100. The first electrode post 30 passes through the end cap 10 and the lower plastic part 20. The first sealing ring 50 is located between the first electrode post 30 and the end cap 10 and is connected to the lower plastic part 20 to seal the assembly gap between the first electrode post 30 and the end cap 10, as well as the assembly gap between the first electrode post 30 and the lower plastic part 20. The first sealing ring 50 serves to insulate the first electrode post 30 and the end cap 10. The second electrode post 40 passes through the end cap 10 and the lower plastic part 20. The second sealing ring 60 is located between the second pole post 40 and the end cap 10, and is connected to the lower plastic 20 to seal the assembly gap between the second pole post 40 and the end cap 10, as well as the assembly gap between the second pole post 40 and the lower plastic 20. The second sealing ring 60 is used to insulate between the second pole post 40 and the end cap 10.

[0062] In this embodiment, the first terminal 30 can be a negative terminal, and the second terminal 40 can be a positive terminal. In other embodiments, the first terminal 30 can be a positive terminal, and the second terminal 40 can be a negative terminal. This application does not impose any restrictions on this.

[0063] As shown in Figures 4 and 5, in this embodiment, the end cap 10 is generally a rectangular plate. The end cap 10 includes a first surface 11 and a second surface 12. The first surface 11 and the second surface 12 are arranged opposite to each other along the thickness direction (i.e., the Z-axis direction) of the end cap 10.

[0064] The end cap 10 also includes a first sealing groove 13 and a second sealing groove 14. Both the first sealing groove 13 and the second sealing groove 14 are recessed in the second surface 12 of the end cap 10 and are recessed in the direction of the first surface 11. The first sealing groove 13 and the second sealing groove 14 are spaced apart along the length direction (i.e., the Y-axis direction) of the end cap 10.

[0065] The first sealing groove 13 is used to mate with the first sealing ring 50 and to accommodate a portion of the first sealing ring 50. The first sealing groove 13 includes a first groove bottom wall 131 and a first groove peripheral wall 132. The first groove peripheral wall 132 surrounds the periphery of the first groove bottom wall 131 and is connected to the first groove bottom wall 131. The first groove peripheral wall 132 is connected to the second surface 12 of the end cap 10. The orientation of the first groove bottom wall 131 is the same as the orientation of the second surface 12. The first sealing groove 13 can be, but is not limited to, a hexagonal groove, a rectangular groove, a circular groove, etc. For example, the first sealing groove 13 is a hexagonal groove.

[0066] The second sealing groove 14 is used to mate with the second sealing ring 60 and to accommodate a portion of the second sealing ring 60. The second sealing groove 14 includes a second groove bottom wall 141 and a second groove peripheral wall 142. The second groove peripheral wall 142 surrounds the periphery of the second groove bottom wall 141 and is connected to the second groove bottom wall 141. The second groove peripheral wall 142 is connected to the second surface 12 of the end cap 10. The orientation of the second groove bottom wall 141 is the same as the orientation of the second surface 12. The second sealing groove 14 can be, but is not limited to, a hexagonal groove, a rectangular groove, a circular groove, etc. Exemplarily, the second sealing groove 14 is always a hexagonal groove.

[0067] The end cap 10 also includes a first through hole 15 and a second through hole 16. The first through hole 15 extends through the first groove bottom wall 131 of the first sealing groove 13 and the first surface 11 of the end cap 10. The first through hole 15 is used for the first pole post 30 to pass through. The second through hole 16 extends through the second groove bottom wall 141 of the second sealing groove 14 and the first surface 11 of the end cap 10. The second through hole 16 is used for the second pole post 40 to pass through. The first through hole 15 and the second through hole 16 can be, but are not limited to, circular holes, hexagonal holes, rectangular holes, etc. For example, both the first through hole 15 and the second through hole 16 are hexagonal holes.

[0068] In this embodiment, the lower plastic 20 is generally a rectangular plate. The lower plastic 20 includes a top surface 21 and a bottom surface 22. The top surface 21 and the bottom surface 22 are arranged opposite to each other along the thickness direction (i.e., the Z-axis direction) of the lower plastic 20.

[0069] The lower plastic 20 also includes a first clearance groove 23 and a second clearance groove 24. Both the first clearance groove 23 and the second clearance groove 24 are recessed on the top surface 21 of the lower plastic 20 and recessed towards the bottom surface 22. The first clearance groove 23 and the second clearance groove 24 are spaced apart along the length direction (i.e., the Y-axis direction) of the lower plastic 20.

[0070] The first clearance groove 23 is used to mate with the first sealing ring 50 and to accommodate a portion of the first sealing ring 50. The first clearance groove 23 includes a third groove peripheral wall 231 and a third groove bottom wall 232. The third groove peripheral wall 231 surrounds the periphery of the third groove bottom wall 232 and connects the third groove bottom wall 232 and the top surface 21 of the lower plastic 20. The orientation of the third groove bottom wall 232 is the same as the orientation of the top surface 21. The first clearance groove 23 can be, but is not limited to, a hexagonal groove, a rectangular groove, a circular groove, etc. For example, the first clearance groove 23 is always a hexagonal groove.

[0071] The second clearance groove 24 is used to mate with the second sealing ring 60 and to accommodate a portion of the second sealing ring 60. The second clearance groove 24 includes a fourth groove peripheral wall 241 and a fourth groove bottom wall 242. The fourth groove peripheral wall 241 surrounds the periphery of the fourth groove bottom wall 242 and connects the fourth groove bottom wall 242 and the top surface 21 of the lower plastic 20. The orientation of the fourth groove bottom wall 242 is the same as the orientation of the top surface 21. The second clearance groove 24 can be, but is not limited to, a hexagonal groove, a rectangular groove, a circular groove, etc. For example, the second clearance groove 24 is always a hexagonal groove.

[0072] The lower plastic 20 also includes a first electrode through-hole 25 and a second electrode through-hole 26. The first electrode through-hole 25 penetrates the third groove bottom wall 232 of the first clearance groove 23 and the bottom surface 22 of the lower plastic 20. The first electrode through-hole 25 is used for the first electrode 30 to pass through. The first electrode through-hole 25 penetrates the fourth groove bottom wall 242 of the second clearance groove 24 and the bottom surface 22 of the lower plastic 20. The second electrode through-hole 26 is used for the second electrode 40 to pass through. The first electrode through-hole 25 and the second electrode through-hole 26 can be, but are not limited to, circular holes, hexagonal holes, rectangular holes, etc. For example, both the first electrode through-hole 25 and the second electrode through-hole 26 are hexagonal holes.

[0073] Please refer to Figures 4, 5 and 6 together. Figure 6 is a cross-sectional view of the first and second sealing rings of the end cap assembly shown in Figure 4.

[0074] In this embodiment, the first sealing ring 50 has a polygonal annular structure. The first sealing ring 50 has a first sealing hole 50a in its center. The first sealing hole 50a is used for the first electrode post 30 to pass through. The first sealing ring 50 is made of a low-temperature resistant and electrolyte-resistant rubber synthetic material such as ethylene propylene diene monomer (EPDM), and it has deformation capability.

[0075] The first sealing ring 50 includes a first segment 51, a second segment 52, and a third segment 53. The second segment 52 connects the first segment 51 and the third segment 53. The first segment 51 and the third segment 53 are spaced apart and opposite each other along the Z-axis. The second segment 52 extends along the axial direction of the first sealing ring 50. The extension direction of the second segment 52 forms an angle with the extension direction of the first segment 51, and the extension direction of the second segment 52 forms an angle with the extension direction of the third segment 53. Exemplarily, both the first segment 51 and the third segment 53 are straight segments. That is, both the first segment 51 and the third segment 53 are parallel to the surface extension direction of the end cap 10. The extension directions of the first segment 51 and the third segment 53 are both perpendicular to the extension direction of the second segment 52. Along a direction perpendicular to the axial direction of the first sealing ring 50, both the first segment 51 and the third segment 53 extend away from the axial direction of the first sealing ring 50.

[0076] It should be noted that the radial width of the first segment 51 is greater than the width of the third segment 53. The first segment 51, the second segment 52, and the third segment 53 together form the first sealing hole 50a. The dashed lines in Figure 6 are for clearly distinguishing the first segment 51, the second segment 52, and the third segment 53.

[0077] In this embodiment, the structure and material of the second sealing ring 60 are the same as those of the first sealing ring 50. The second sealing ring 60 has a polygonal annular structure. The second sealing ring 60 has a second sealing hole 60a in the middle. The second sealing hole 60a is used for the second pole post 40 to pass through. The second sealing ring 60 is made of a low-temperature resistant and electrolyte-resistant rubber synthetic material such as EPDM, and it has deformation capability.

[0078] The second sealing ring 60 includes a fourth segment 61, a fifth segment 62, and a sixth segment 63. The fifth segment 62 connects to the fourth segment 61 and the sixth segment 63. The fourth segment 61 and the sixth segment 63 are spaced apart and opposite each other along the Z-axis. The extension direction of the fifth segment 62 extends along the axial direction of the second sealing ring 60. The extension direction of the fifth segment 62 forms an angle with the extension direction of the fourth segment 61, and the extension direction of the fifth segment 62 forms an angle with the extension direction of the sixth segment 63. Exemplarily, both the fourth segment 61 and the sixth segment 63 are straight segments, meaning they are both parallel to the surface extension direction of the end cap 10. The extension directions of the fourth segment 61 and the sixth segment 63 are both perpendicular to the extension direction of the fifth segment 62. Along a direction perpendicular to the axial direction of the second sealing ring 60, both the fourth segment 61 and the sixth segment 63 extend away from the axial direction of the second sealing ring 60.

[0079] It should be noted that the radial width of the sixth segment 63 is greater than the width of the fourth segment 61. The fourth segment 61, the fifth segment 62, and the sixth segment 63 together form the second sealing hole 60a. The dashed lines in Figure 6 are for clearly distinguishing the fourth segment 61, the fifth segment 62, and the sixth segment 63.

[0080] In some embodiments, the structure of the second sealing ring 60 may differ from that of the first sealing ring 50. Alternatively, the material of the second sealing ring 60 may differ from that of the first sealing ring 50. This application does not impose any limitations on this.

[0081] Please refer to Figures 4, 5 and 7 together. Figure 7 is a cross-sectional view of the first pole and the second pole of the end cap assembly shown in Figure 4 in a first embodiment.

[0082] In this embodiment, the first pole post 30 is a column with an "I"-shaped cross-section. The first pole post 30 includes a first pole post body 31 and a first flange 32. Along the height direction (i.e., the Z-axis direction) of the first pole post 30, the first flange 32 is connected to one end of the first pole post body 31. For example, the first flange 32 is connected to the bottom end face of the first pole post body 31.

[0083] The first flange 32 includes a first connecting surface 321 and a first flange surface 322. The first connecting surface 321 and the first flange surface 322 are disposed opposite to each other along the thickness direction of the first flange 32. The first connecting surface 321 surrounds the first pole body 31. The first flange surface 322 faces away from the first pole body 31.

[0084] The first flange 32 also includes a first step 323. The first step 323 is located on the outer peripheral surface of the first flange 32, and is recessed in the first connecting surface 321 and recessed towards the second connecting surface 421. It can be understood that the first step 323 is formed by cutting the periphery of the end of the first flange 32 near the first pole body 31. Exemplarily, the cross-section of the first flange 32 can be approximately an inverted "T" shaped column.

[0085] The first step 323 includes a first step surface 324 and a first mounting surface 325. The first step surface 324 connects the first mounting surface 325 and the first connecting surface 321 of the first flange 32, and the first step surface 324 is set at an angle to both the first connecting surface 321 and the first mounting surface 325. The orientation of the first mounting surface 325 is the same as that of the first connecting surface 321.

[0086] The first pole body 31 is connected to the first connecting surface 321 of the first flange 32. The first pole body 31 and the first flange 32 are coaxially arranged. The first pole body 31 includes a first mounting surface 311 and a first peripheral side surface 312. The first peripheral side surface 312 is arranged around the periphery of the first mounting surface 311 and is connected to the first mounting surface 311 and the first connecting surface 321. The first mounting surface 311 faces away from the first flange 32.

[0087] In this embodiment, a first protrusion 313 protrudes from the center of the first mounting surface 311 of the first pole body 31. It can be understood that the first pole body 31 also includes the first protrusion 313, which protrudes from the first mounting surface 311 and is located at the center of the first mounting surface 311. The first protrusion 313 includes a first welding surface 314. The first welding surface 314 faces away from the first mounting surface 311, and the orientation of the first welding surface 314 is the same as the orientation of the first mounting surface 311. The first protrusion 313 can be welded to a conductor (such as a connecting piece) outside the energy storage device 1000 through the first welding surface 314 to achieve an electrical connection between the first pole 30 and the conductor (such as a connecting piece) outside the energy storage device 1000. The first protrusion 313 can be, but is not limited to, a circular protrusion, a hexagonal protrusion, a rectangular protrusion, etc. For example, the first pole body 31 is generally a cylinder. The first protrusion 313 is a hexagonal protrusion.

[0088] The first pole post 30 also includes a first folded portion 33. The first folded portion 33 protrudes from the periphery of the end of the first pole post body 31 away from the first flange 32 and surrounds the first mounting surface 311. The width direction of the first folded portion 33 is angled to the axial direction of the first pole post body 31. Along the height direction of the first pole post 30, the first folded portion 33 is opposite to and spaced apart from the first flange 32. The first folded portion 33 is used to mate with the first flange 32 to press against the first sealing ring 50. The first folded portion 33 is formed by a flanging operation. Exemplarily, the width direction of the first folded portion 33 is angled at 90 degrees to the axial direction of the first pole post body 31.

[0089] The first folding portion 33 includes a first sealing surface 331 and a first outer surface 332. The first sealing surface 331 and the first outer surface 332 are disposed opposite to each other along the thickness direction of the first folding portion 33. The first sealing surface 331 is connected to the first peripheral side surface 312 of the first pole body 31 and is disposed at an angle to the first peripheral side surface 312, and the first sealing surface 331 is opposite to and spaced apart from the first connecting surface 321 of the first flange 32 along the Z-axis direction. The first outer surface 332 is connected to the first mounting surface 311 of the first pole body 31. The first outer surface 332 may be flush with the first mounting surface 311, or the first mounting surface 311 may protrude from the first outer surface 332 along the direction from the first folding portion 33 to the first flange 32. For example, the first outer surface 332 is flush with the first mounting surface 311, and the first sealing surface 331 is disposed at a 90-degree angle to the first peripheral side surface 312.

[0090] It should be noted that the first folding part 33 can be integrally formed with the first pole body 31, or it can be formed separately from the first pole body 31 and connected by welding, bonding or other means.

[0091] In this embodiment, the structure of the second pole post 40 is the same as that of the first pole post 30. The second pole post 40 is a column with an "I"-shaped cross-section. Along the height direction (i.e., the Z-axis direction) of the second pole post 40, the second flange 42 is connected to one end of the second pole post body 41. For example, the first flange 32 is connected to the bottom end face of the first pole post body 31.

[0092] The second flange 42 includes a second connecting surface 421 and a second flange surface 422. The second connecting surface 421 and the second flange surface 422 are disposed opposite to each other along the thickness direction of the second flange 42. The second connecting surface 421 surrounds the second pole body 41. The second flange surface 422 faces away from the second pole body 41.

[0093] The second flange 42 also includes a second step 423. The second step 423 is located on the outer peripheral surface of the second flange 42, and is recessed in the second connecting surface 421 and recessed towards the second flange surface 422. It can be understood that the second step 423 is formed by cutting the periphery of the end of the second flange 42 near the second pole body 41. Exemplarily, the cross-section of the second flange 42 can be approximately an inverted "T" shaped column.

[0094] The second step 423 includes a second step surface 424 and a second mounting surface 425. The second step surface 424 is connected to the second mounting surface 425 and the second connecting surface 421 of the second flange 42, and the second step surface 424 is set at an angle to the second connecting surface 421 and the second mounting surface 425, respectively. The orientation of the second mounting surface 425 is the same as that of the second connecting surface 421.

[0095] The second pole body 41 is connected to the second connecting surface 421 of the second flange 42. The second pole body 41 and the second flange 42 are coaxially arranged. The second pole body 41 includes a second mounting surface 411 and a second peripheral side surface 412. The second peripheral side surface 412 is arranged around the periphery of the second mounting surface 411 and is connected to the second mounting surface 411 and the second connecting surface 421. The second mounting surface 411 faces away from the second flange 42.

[0096] In this embodiment, a second protrusion 413 protrudes from the middle of the second mounting surface 411 of the second pole body 41. It can be understood that the second pole body 41 also includes the second protrusion 413, which protrudes from the second mounting surface 411 and is located at the middle of the second mounting surface 411. The second protrusion 413 includes a second welding surface 414. The second welding surface 414 faces away from the second mounting surface 411, and the orientation of the second welding surface 414 is the same as the orientation of the second mounting surface 411. The second protrusion 413 can be welded to a conductor (such as a connecting piece) outside the energy storage device 1000 through the second welding surface 414 to achieve an electrical connection between the second pole 40 and the conductor (such as a connecting piece) outside the energy storage device 1000. The second protrusion 413 can be, but is not limited to, a circular protrusion, a hexagonal protrusion, a rectangular protrusion, etc. For example, the second pole body 41 is generally a column. The second protrusion 413 is a hexagonal protrusion.

[0097] The second pole post 40 also includes a second folded portion 43. The second folded portion 43 protrudes from the periphery of the end of the second pole post body 41 away from the second flange 42 and surrounds the second mounting surface 411. The width direction of the second folded portion 43 is angled to the axial direction of the second pole post body 41. Along the height direction of the second pole post 40, the second folded portion 43 is opposite to and spaced apart from the second flange 42. The second folded portion 43 is used to mate with the second flange 42 to press the second sealing ring 60. The second folded portion 43 is formed by a flanging operation. Exemplarily, the width direction of the second folded portion 43 is angled at 90 degrees to the axial direction of the second pole post body 41.

[0098] The second folding portion 43 includes a second sealing surface 431 and a second outer surface 432. The second sealing surface 431 and the second outer surface 432 are disposed opposite to each other along the thickness direction of the second folding portion 43. The second sealing surface 431 is connected to the second peripheral side surface 412 of the second pole body 41 and is disposed at an angle to the second peripheral side surface 412, and the second sealing surface 431 is opposite to and spaced from the second connecting surface 421 of the second flange 42 along the Z-axis direction. The second outer surface 432 is connected to the second mounting surface 411 of the second pole body 41. The second outer surface 432 may be flush with the second mounting surface 411, or the second mounting surface 411 may protrude from the second outer surface 432 along the direction from the second folding portion 43 to the second flange 42. Exemplarily, the second outer surface 432 is flush with the second mounting surface 411, and the second sealing surface 431 is disposed at a 90-degree angle to the second peripheral side surface 412.

[0099] It should be noted that the second folding part 43 can be integrally formed with the second pole body 41, or it can be formed separately from the second pole body 41 and connected by welding, bonding or other means.

[0100] In some embodiments, the structure of the second pole post 40 may differ from the structure of the first pole post 30. This application does not impose any limitations on this.

[0101] Please refer to Figure 8, which is a cross-sectional view of the end cap assembly shown in Figure 3.

[0102] The lower plastic 20 and the end cap 10 are stacked along the Z-axis. Specifically, the top surface 21 of the lower plastic 20 is connected to the second surface 12 of the end cap 10. The opening of the first clearance groove 23 of the lower plastic 20 is opposite to and communicates with the opening of the first sealing groove 13 of the end cap 10. The third groove bottom wall 232 of the first clearance groove 23 is opposite to the first groove bottom wall 131 of the first sealing groove 13, forming a first gap H1. The first gap H1 communicates with the first through hole 15 and the first pole post through hole 25. The first gap H1 is used to accommodate a portion of the third section 53 of the first sealing ring 50. The first pole post through hole 25 of the lower plastic 20 is connected to and coaxially arranged with the first through hole 15 of the end cap 10. The opening of the second clearance groove 24 of the lower plastic 20 is opposite to and communicates with the opening of the second sealing groove 14 of the end cap 10. The fourth groove bottom wall 242 of the second clearance groove 24 is opposite to the second groove bottom wall 141 of the second sealing groove 14, forming a second gap H2. The second gap H2 communicates with the second pole post through hole 26 and the second through hole 16. The second gap H2 is used to accommodate the sixth segment 63 of the second sealing ring 60. The second pole post through hole 26 of the lower plastic 20 and the second through hole 16 of the end cap 10 are connected and coaxially arranged.

[0103] The first electrode post 30, the second electrode post 40, the first sealing ring 50, and the second sealing ring 60 are mounted together on the lower plastic 20 and the end cap 10 to form the end cap assembly 100. The first electrode post 30 passes through the first sealing hole 50a of the first sealing ring 50, and together with the first sealing ring 50, passes through the first electrode post through hole 25 of the lower plastic 20 and the first through hole 15 of the end cap 10. The first sealing ring 50 is interference-fitted with the end cap 10, the lower plastic 20, and the first electrode post 30.

[0104] The first sealing ring 50 is fitted around the outer periphery of the first pole body 31, and then together with the first pole 30, is mounted on the end cap 10 and the lower plastic part 20. The first flange 32 of the first pole 30, the lower plastic part 20, the end cap 10, and the first folding part 33 together clamp the first sealing ring 50, and the end cap 10, the lower plastic part 20, and the first pole 30 compress the first sealing ring 50. The portion of the first sealing ring 50 clamped between the lower plastic part 20 and the end cap 10 extends into the first gap H1. The mating relationship after assembly is described below, and the specific assembly sequence will be described later. The first sealing ring 50 is located between the first flange 32 and the first folding part 33. The portion of the end cap 10 around the first through hole 15 is located between the first section 51 and the third section 53 of the first sealing ring 50. The end cap 10, the first section 51, and the third section 53 are clamped by the first folding part 33 and the first flange 32.

[0105] Specifically, the first segment 51 of the first sealing ring 50 is connected to the first sealing surface 331 of the first folded portion 33 and the first surface 11 of the end cap 10. The first segment 51 is interference-fitted with the end cap 10 and the first folded portion 33, which not only seals the assembly gap between the first folded portion 33 and the end cap 10, effectively preventing electrolyte splashed from the outside of the energy storage device 1000 from seeping into the interior of the first electrode post 30 through the assembly gap, thus improving the reliability of the end cap assembly 100, but also insulates the first folded portion 33 from the end cap 10. When the first electrode post 30 and the first sealing ring 50 are assembled to the end cap 10, the first folded portion 33 and the end cap 10 compress the first segment 51, causing the first segment 51 to deform and extend towards both ends in its width direction (i.e., the end connected to the second segment 52 and the end away from the second segment 52). The outer peripheral surface of the first segment 51 protrudes beyond the outer peripheral surface of the first folded portion 33 to increase the creepage distance from the end cap 10 to the first electrode post 30, ensuring the safety and reliability of the end cap assembly 100. Because the first segment 51 is interference-fitted with the first folded portion 33 and the end cap 10, the first segment 51 has a first compression amount. This first compression amount is the difference between the thickness of the first segment 51 before compression and the thickness after compression.

[0106] The second segment 52 of the first sealing ring 50 is connected to the first peripheral side 312 of the first electrode body 31 and the wall of the first through hole 15 of the end cap 10, and is interference-fitted with the end cap 10 and the first electrode body 31. This not only seals the assembly gap between the first electrode body 31 and the end cap 10, effectively preventing electrolyte from seeping into the first electrode 30 through the assembly gap and improving the reliability of the end cap assembly 100, but also insulates the first electrode body 31 from the end cap 10. When the first electrode 30 and the first sealing ring 50 are assembled to the end cap 10, the first electrode body 31 and the end cap 10 compress the second segment 52, causing the second segment 52 to deform and extend towards the first segment 51 and the third segment 53. Because the second segment 52 is interference-fitted with the first electrode body 31 and the end cap 10, the second segment 52 has a certain amount of compression. In some embodiments, the second segment 52 may not be interference-fitted with the first pole body 31 and the end cap 10, that is, the first pole body 31 and the end cap 10 do not press against the second segment 52, so the second segment 52 may not be compressed.

[0107] The third segment 53 of the first sealing ring 50 is connected to the first connecting surface 321 of the first flange 32 and the first groove bottom wall 131 of the first sealing groove 13 of the end cover 10, and is interference-fitted with the end cover 10 and the first flange 32. This not only seals the assembly gap between the first flange 32 and the end cover 10, effectively preventing electrolyte from seeping into the first electrode post 30 from the assembly gap and improving the reliability of the end cover assembly 100, but also insulates the first flange 32 from the end cover 10. In addition, when the first electrode post 30 and the first sealing ring 50 are assembled to the end cover 10, the first flange 32 and the end cover 10 compress the third segment 53, causing the third segment 53 to deform and extend to both ends in its width direction (i.e., the end connected to the second segment 52 and the end away from the second segment 52). The third segment 53 is squeezed into the first gap H1 between the first sealing groove 13 and the first relief groove 23 of the lower plastic 20, and connects the first groove bottom wall 131 of the first sealing groove 13 and the third groove bottom wall 232 of the first relief groove 23. It is understandable that the outer peripheral surface of the third segment 53 protrudes beyond the outer peripheral surface of the first flange 32. The third segment 53 can cover the assembly gap between the lower plastic 20 and the first electrode post 30, preventing metal powder from remaining in this gap and causing a short circuit between the end cap 10 and the first electrode post 30, thus improving the voltage withstand capability of the end cap assembly 100. Because the third segment 53 has an interference fit with the first flange 32, the lower plastic 20, and the end cap 10, the third segment 53 has a second compression amount. The second compression amount is the difference between the thickness of the third segment 53 before compression and the thickness after compression.

[0108] Because the radial width of the first segment 51 is smaller than the radial width of the third segment 53, the contact area between the first segment 51 and the first surface 11 of the end cap 10 is smaller than the contact area between the third segment 53 and the second surface 12 of the end cap 10. That is, the projection of the first segment 51 in the thickness direction of the end cap assembly 100 lies within the projection of the third segment 53 in the thickness direction of the end cap assembly 100, thus ensuring the fixation of the first sealing ring 50 after the first pole post 30 is flanged, and improving the stability of the compression amount of the first sealing ring 50.

[0109] The first step 323 of the first flange 32 mates with the lower plastic 20. The first step surface 324 of the first step 323 is opposite to and spaced from the wall of the first pole through hole 25 of the lower plastic 20. The first mounting surface 325 abuts against the bottom surface 22 of the lower plastic 20. The first step 323 not only limits the movement between the first pole 30 and the lower plastic 20, but also abuts the lower plastic 20 against the end cap 10, preventing the lower plastic 20 from detaching from the end cap 10 under gravity. In some embodiments, the third segment 53 of the first sealing ring 50 can also be squeezed into the mounting gap between the first step surface 324 and the wall of the first pole through hole 25 to seal the first pole 30 and the lower plastic 20, further increasing the sealing performance of the end cap assembly 100 and improving the reliability of the end cap assembly 100.

[0110] It should be noted that, through efficient testing with tools, the sum of the first compression of the first segment 51 and the second compression of the third segment 53 of the assembled first sealing ring 50 is 5% to 55% (including the endpoint values ​​of 5% and 55%) of the sum of the thicknesses of the first segment 51 and the third segment 53 before compression. Since both the first segment 51 and the third segment 53 have a certain amount of compression, even when the first sealing ring 50 is subjected to high temperature, the first segment 51 and the third segment 53 can prevent the first pole post 30 from sinking due to gravity.

[0111] The second electrode post 40 passes through the second sealing hole 60a of the second sealing ring 60, and together with the second sealing ring 60, passes through the second electrode post through hole 26 of the lower plastic 20 and the second through hole 16 of the end cap 10. The second sealing ring 60 is interference-fitted with the end cap 10, the lower plastic 20, and the second electrode post 40.

[0112] The second sealing ring 60 is fitted around the outer periphery of the second pole body 41, and then together with the second pole 40, is mounted on the end cap 10 and the lower plastic part 20. The second flange 42 of the second pole 40, the lower plastic part 20, the end cap 10, and the second folding part 43 together clamp the second sealing ring 60, and the end cap 10, the lower plastic part 20, and the second pole 40 compress the second sealing ring 60. The portion of the second sealing ring 60 clamped between the lower plastic part 20 and the end cap 10 extends into the second gap H2. The mating relationship after assembly is described below, and the specific assembly sequence will be described later. The second sealing ring 60 is located between the second flange 42 and the second folding part 43. The portion of the end cap 10 around the second through hole 16 is located between the fourth segment 61 and the sixth segment 63 of the second sealing ring 60. The end cap 10, the fourth segment 61, and the sixth segment 63 are clamped by the second folding part 43 and the second flange 42.

[0113] Specifically, the fourth segment 61 of the second sealing ring 60 is connected to the second sealing surface 431 of the second folded portion 43 and the second surface 12 of the end cap 10. The fourth segment 61 is press-fitted with the end cap 10 and the second folded portion 43, which not only seals the assembly gap between the second folded portion 43 and the end cap 10, effectively preventing electrolyte splashed from the outside of the energy storage device 1000 from seeping into the interior of the second electrode post 40 through the assembly gap, thus improving the reliability of the end cap assembly 100, but also insulates the second folded portion 43 from the end cap 10. When the second electrode post 40 and the second sealing ring 60 are assembled to the end cap 10, the second folded portion 43 and the end cap 10 compress the fourth segment 61, causing the fourth segment 61 to deform and extend towards both ends in its width direction (i.e., the end connected to the second segment 52 and the end away from the second segment 52). The outer peripheral surface of the fourth segment 61 protrudes beyond the outer peripheral surface of the second folded portion 43 to increase the creepage distance from the end cap 10 to the second pole post 40, ensuring the safety of the end cap assembly 100. Because the fourth segment 61 is interference-fitted with the second folded portion 43 and the end cap 10, the fourth segment 61 has a third compression amount. This third compression amount is the difference between the thickness of the fourth segment 61 before compression and its thickness after compression.

[0114] The fifth segment 62 of the second sealing ring 60 is connected to the second peripheral side 412 of the second electrode body 41 and the wall of the second through hole 16 of the end cap 10, and is interference-fitted with the end cap 10 and the second electrode body 41. This not only seals the assembly gap between the second electrode body 41 and the end cap 10, effectively preventing electrolyte from seeping into the second electrode 40 from the assembly gap and improving the reliability of the end cap assembly 100, but also insulates the second electrode body 41 from the end cap 10. When the second electrode 40 and the second sealing ring 60 are assembled to the end cap 10, the second electrode body 41 and the end cap 10 compress the fifth segment 62, causing the fifth segment 62 to deform and extend towards the fourth segment 61 and the sixth segment 63. Because the fifth segment 62 is interference-fitted with the second electrode body 41 and the end cap 10, the fifth segment 62 has a certain amount of compression. In some embodiments, the fifth segment 62 may not be interference-fitted with the second pole body 41 and the end cap 10, that is, the second pole body 41 and the end cap 10 do not press against the fifth segment 62, and thus the fifth segment 62 may not be compressed.

[0115] The sixth segment 63 of the second sealing ring 60 is connected to the second connecting surface 421 of the second flange 42 and the second groove bottom wall 141 of the second sealing groove 14 of the end cover 10, and is press-fitted with the end cover 10 and the second flange 42. This not only seals the assembly gap between the second flange 42 and the end cover 10, effectively preventing electrolyte from seeping into the interior of the second electrode post 40 from the assembly gap and improving the reliability of the end cover assembly 100, but also insulates the second flange 42 from the end cover 10. In addition, when the second electrode post 40 and the second sealing ring 60 are assembled to the end cover 10, the second flange 42 and the end cover 10 compress the sixth segment 63, causing the sixth segment 63 to deform and extend to both ends in its width direction (i.e., the end connected to the fifth segment 62 and the end away from the fifth segment 62). The sixth segment 63 is squeezed into the second gap H2 between the second sealing groove 14 and the second relief groove 24 of the lower plastic 20, and connects the second groove bottom wall 141 of the second sealing groove 14 and the fourth groove bottom wall 242 of the second relief groove 24. It is understood that the outer peripheral surface of the sixth segment 63 protrudes beyond the outer peripheral surface of the second flange 42. The sixth segment 63 can cover the assembly gap between the lower plastic 20 and the second pole post 40, preventing metal powder from remaining in this gap and causing a short circuit between the end cap 10 and the second pole post 40, thus improving the voltage withstand capability of the end cap assembly 100. Because the sixth segment 63 is interference-fitted with the second flange 42, the lower plastic 20, and the end cap 10, the sixth segment 63 has a fourth compression amount. This fourth compression amount is the difference between the thickness of the sixth segment 63 before compression and the thickness after compression.

[0116] Because the radial width of the fourth segment 61 is smaller than that of the sixth segment 63, the contact area between the fourth segment 61 and the first surface 11 of the end cap 10 is smaller than the contact area between the sixth segment 63 and the second surface 12 of the end cap 10. That is, the projection of the fourth segment 61 in the thickness direction of the end cap assembly 100 lies within the projection of the sixth segment 63 in the thickness direction of the end cap assembly 100, thus ensuring the fixation of the second sealing ring 60 after the second pole post 40 is flanged, and improving the stability of the compression amount of the second sealing ring 60.

[0117] The second step 423 of the second flange 42 mates with the lower plastic 20. The second step surface 424 of the second step 423 is opposite to and spaced from the wall of the second pole through hole 26 of the lower plastic 20. The second mounting surface 425 abuts against the bottom surface 22 of the lower plastic 20. The second step 423 not only limits the movement between the second pole 40 and the lower plastic 20, but also abuts the lower plastic 20 against the end cap 10, preventing the lower plastic 20 from detaching from the end cap 10 under gravity. In some embodiments, the sixth segment 63 of the second sealing ring 60 can also be squeezed into the mounting gap between the second step surface 424 and the wall of the second pole through hole 26 to seal the second pole 40 and the lower plastic 20, further increasing the sealing performance and reliability of the end cap assembly 100.

[0118] It should be noted that, through efficient testing with tools, the sum of the third compression of the fourth segment 61 and the fourth compression of the sixth segment 63 of the assembled second sealing ring 60 is 5% to 55% (including the endpoint values ​​of 5% and 55%) of the sum of the thicknesses of the fourth segment 61 and the sixth segment 63 before compression. Since both the fourth segment 61 and the sixth segment 63 have a certain amount of compression, even when the second sealing ring 60 is subjected to high temperatures, the fourth segment 61 and the sixth segment 63 can prevent the second pole post 40 from sinking due to gravity.

[0119] Please refer to Figures 9a, 9b, and 9c. Figure 9a is a schematic diagram of the first pole, first sealing ring, end cap, and lower plastic fitting together before assembly of the end cap assembly shown in Figure 3. Figure 9b is a schematic diagram of the first pole, first sealing ring, end cap, and lower plastic fitting together during the assembly process of the end cap assembly shown in Figure 9a. Figure 9c is a schematic diagram of the first pole, first sealing ring, end cap, and lower plastic fitting together after assembly of the end cap assembly shown in Figure 9b.

[0120] After the lower plastic 20 and the end cap 10 are assembled, the first clearance groove 23 of the lower plastic 20 and the first sealing groove 13 of the end cap 10 form a first gap H1, and the second clearance groove 24 of the lower plastic 20 and the second sealing groove 14 of the end cap 10 form a second gap H2.

[0121] When the first segment 51 of the first sealing ring 50 is not installed on the end cap 10 and the lower plastic 20, it extends along the axial direction of the first sealing ring 50, that is, the extension direction of the first segment 51 is the same as the extension direction of the second segment 52. The first sealing ring 50 shown in Figure 8 is the assembled form, and the structure of the first sealing ring 50 is described in the assembled form. For ease of description, the first sealing ring 50 before assembly is referred to as the first sealing ring 50 before assembly.

[0122] When the first pole post 30 is not installed on the end cap 10 and the lower plastic 20, it is in its unflanged state. This first pole post 30 can be understood as the first pole post 30 before assembly, while the first pole post 30 shown in Figure 8 is the assembled state. For ease of description, the first pole post 30 before assembly is referred to as the first pole post 30 before assembly. The first pole post 30 before assembly includes a first folded base 33a, which surrounds the periphery of the first pole post body 31 and protrudes from the first mounting surface 311 of the first pole post body 31. The height direction of the first folded base 33a is consistent with the axial direction of the first pole post 30, and the height of the first folded base 33a is greater than the height of the first protrusion 313.

[0123] The first folded portion base 33a can be formed into the first folded portion 33 by a flanging operation. The first folded portion base 33a includes a first outer ring surface and a first inner ring surface, which are arranged opposite to each other along the thickness direction of the first folded portion base 33a. The first outer ring surface is connected to the first peripheral side surface 312 of the first pole post body 31, and the orientation of the first outer ring surface is the same as the orientation of the first peripheral side surface 312. The first outer ring surface is used to form the first sealing surface 331 of the first folded portion 33. The first inner ring surface is connected to the first mounting surface 311 and is arranged at an angle to the first mounting surface 311. The first inner ring surface is used to form the first outer surface 332 of the first folded portion 33.

[0124] Before assembly, the first pole post 30 also includes a first groove 35. The first groove 35 is arranged around the axial direction of the first pole post 30 and is formed between the first folded portion base 33a and the first protrusion 313. The first mounting surface 311 of the first pole post body 31 is the surface of the bottom wall of the groove 35. The first inner annular surface of the first folded portion base 33a and the outer peripheral surface of the first protrusion 313 are the surfaces of the sidewalls of the groove 35. It can be understood that the first groove 35 is an annular groove. The first groove is used to release the stress experienced during the formation of the first folded portion 33, prevent the first pole post body 31 from deforming, and improve the structural stability of the first pole post 30. The first groove 35 can also separate the first protrusion 313 and the first folded portion base 33a to prevent the first outer surface 332 of the first folded portion 33 formed after the first folded portion base 33a is subjected to the folding operation from protruding from the first welding surface 314 of the first protrusion 313, thereby preventing the problem of poor welding when the first pole post 30 is welded to the conductor (such as the connecting piece) outside the energy storage device 1000.

[0125] Referring again to Figure 9a, the first pole post 30 before assembly passes through the first sealing hole 50a of the first sealing ring 50 before assembly, and together with the first sealing ring 50 before assembly, they can pass through the first pole post through hole 25 and the first through hole 15 sequentially from bottom to top along the Z-axis direction. That is, the first flange 32 protrudes from the bottom surface 22 of the lower plastic 20, and the orientation of the first flange surface 322 is the same as the orientation of the bottom surface 22 of the lower plastic 20. The first protrusion 313 and the first folded portion 33 protrude from the first surface 11 of the end cover 10. The orientation of the first mounting surface 311 of the first pole post body 31 is the same as the orientation of the first surface 11 of the end cover 10, and the orientation of the first flange surface 322 is the same as the orientation of the bottom surface 22 of the lower plastic 20. Before assembly, the first segment 51 of the first sealing ring 50 is connected to the first outer annular surface of the first folded portion base 33a, and the first segment 51 and the first folded portion base 33a extend in the same direction; and the length of the first segment 51 protruding from the end cap 10 is less than the length of the first folded portion base 33a protruding from the end cap 10. The first sealing ring 50 and the first electrode post 30 before assembly are installed on the end cap 10 and the lower plastic 20, and the specific fit can be referred to Figure 8 and the above description. In some embodiments, the length of the first segment 51 protruding from the end cap 10 can also be equal to or greater than the length of the first folded portion base 33a protruding from the end cap 10, so that the first sealing ring 50 can fully separate the first electrode post 30 and the end cap 10, further improving the creepage distance.

[0126] As shown in Figure 9b, a flanging operation is performed on the first folding portion base 33a, flipping it away from the axis O1-O1 of the first pole post 30 before assembly, and then flipping it along the direction from the end cap 10 to the lower plastic 20 until it forms an acute angle with the axis O1-O1 of the first pole post 30. For example, along the direction from the end cap 10 to the lower plastic 20, the first folding portion base 33a is flipped to form a 45-degree angle with the axis O1-O1 of the first pole post 30. At this time, the first folding portion base 33a presses the first segment 51 towards the end cap 10, so that the first segment 51 forms a 45-degree angle with the end cap 10.

[0127] As shown in Figure 9c, the first folded portion base 33a is further folded so that it can be flipped to be perpendicular to the axis O1-O1 of the first pole post 30, thus forming the first folded portion 33. At this time, the first segment 51 is held between the first folded portion 33 and the end cap 10, and the first segment 51 is connected to the first sealing surface 331 of the first folded portion 33 and the first surface 11 of the end cap 10. The first outer surface 332 of the first folded portion 33 is flush with the first mounting surface 311 of the first pole post body 31, and a crease (i.e., the dashed line in Figure 9c) is visible between the first outer surface 332 and the first mounting surface 311. That is, the first outer surface 332 of the first folded portion 33 is flush with the bottom wall of the first groove 35, and the crease at the connection between the first groove 35 and the first folded portion 33 is visible. In some embodiments, along the direction from the end cap 10 to the lower plastic 20, the first folding portion base 33a can be flipped to form an obtuse angle with the axis O1-O1 of the first pole post 30. The first outer surface 332 of the formed first folding portion 33 is set at an angle to the first mounting surface 311, and the first outer surface 332 is inclined towards the first flange 32, which can be understood as the first outer surface 332 being recessed relative to the bottom wall of the first groove 35.

[0128] Since the second pole post 40 and the first pole post 30 in this application embodiment have the same structure, the assembly process diagram of the second pole post 40 is consistent with the assembly process shown in Figures 9a to 9c, and will not be described here.

[0129] Please refer to Figures 10 and 11. Figure 10 is an exploded view of the end cap assembly of the energy storage device shown in Figure 2 in a second embodiment, and Figure 11 is an exploded view of the end cap assembly shown in Figure 10 from another angle.

[0130] The end cap assembly 100 in the second embodiment differs from the end cap assembly 100 in the structure of the end cap 10 and the lower plastic 20.

[0131] Specifically, as shown in Figures 10 and 11, the top surface 21 of the lower plastic 20 is recessed to form a first clearance groove 23, and the bottom surface 22 is protruded to form a protrusion (not shown in the figure).

[0132] The lower plastic 20 also includes limiting posts 27. The limiting posts 27 protrude from the top surface 21 of the lower plastic 20. The limiting posts 27 are used to mate with the end cap 10. There are multiple limiting posts 27. The multiple limiting posts 27 are spaced apart along the edge of the lower plastic 20. The shape of the limiting posts 27 can be, but is not limited to, cylinders, cones, frustums, etc. For example, there are twelve limiting posts 27. The limiting posts 27 are cylinders.

[0133] As shown in Figure 11, the end cap 10 does not include the first sealing groove 13 and the second sealing groove 14. The first through hole 15 and the second through hole 16 of the end cap 10 both penetrate the first surface 11 and the second surface 12 of the end cap 10. The end cap 10 also includes a limiting groove 17. The limiting groove 17 is recessed in the second surface 12 of the end cap 10 and is recessed towards the first surface 11. There are multiple limiting grooves 17. The multiple limiting grooves 17 are spaced apart along the edge of the end cap 10. Each limiting groove 17 is used to accommodate a limiting post 27, and the shape of the limiting groove 17 matches the shape of the limiting post 27. For example, there are twelve limiting grooves 17. The limiting groove 17 is a circular groove.

[0134] Please refer to Figures 10, 11 and 12. Figure 12 is a cross-sectional view of a second embodiment of the first and second poles of the end cap assembly shown in Figure 10.

[0135] In the second embodiment, the structure of the first pole post 30 differs from that in the first embodiment described above. The assembly positions of the first pole post 30 with the end cap 10 and the lower plastic 20 are different. The first flange 32 of the first pole post 30 protrudes from the first surface 11 of the end cap 10, and the orientation of the first flange face 322 of the first flange 32 is the same as the orientation of the first surface 11. The first protrusion 313 and the first folded portion 33 of the first pole post 30 protrude from the second surface 12 of the end cap 10, and the orientation of the first welding surface 314 of the first protrusion 313 and the orientation of the first outer surface 332 of the first folded portion 33 are both the same as the orientation of the second surface 12. The first protrusion 313 can be welded to a conductor (such as a pin or tab) inside the energy storage device 1000 through the first welding surface 314 to achieve an electrical connection between the first pole post 30 and the conductor (such as a pin or tab) inside the energy storage device 1000. The first flange 32 is a column and does not include the first step 323.

[0136] The first pole post 30 also includes a first groove 35, which is arranged around the axial direction of the first pole post 30 and is formed between the first folded portion 33 and the first protrusion 313. The first mounting surface 311 of the first pole post body 31 is the surface of the bottom wall of the groove 35. The two opposing surfaces of the first folded portion 33 and the first protrusion 313 are the surfaces of the side walls of the groove 35. The first groove 35 is used to separate the first protrusion 313 and the first folded portion 33 to prevent the first outer surface 332 of the first folded portion 33 from protruding relative to the first welding surface 314 of the first protrusion 313, thereby avoiding the problem of poor soldering when the first pole post 30 is soldered to the conductors (such as pins or tabs) inside the energy storage device 1000.

[0137] Furthermore, unlike the structure of the second pole post 40 in the first embodiment described above, in this embodiment, the assembly positions of the second pole post 40 with the end cap 10 and the lower plastic 20 are different. The second flange 42 of the second pole post 40 protrudes from the first surface 11 of the end cap 10, and the orientation of the second flange face 422 of the second flange 42 is the same as the orientation of the first surface 11. The second protrusion 413 and the second folded portion 43 of the second pole post 40 protrude from the second surface 12 of the end cap 10, and the orientation of the second welding surface 414 of the second protrusion 413 and the orientation of the second outer surface 432 of the second folded portion 43 are both the same as the orientation of the second surface 12. The second protrusion 413 can be welded to a conductor (such as a pin or tab) inside the energy storage device 1000 through the second welding surface 414 to achieve an electrical connection between the second pole post 40 and the conductor (such as a pin or tab) inside the energy storage device 1000. The second flange 42 is a column, and it does not include the second step 423.

[0138] The second pole post 40 also includes a second groove 45, which is arranged around the axial direction of the second pole post 40 and is located between the second folded portion 43 and the second protrusion 413. The second mounting surface 411 of the second pole post body 41 is the surface of the bottom wall of the groove 45. The two opposing surfaces of the second folded portion 43 and the second protrusion 413 are the surfaces of the side walls of the groove 45. The second groove 45 is used to separate the second protrusion 413 and the second folded portion 43 to prevent the second outer surface 432 of the second folded portion 43 from protruding relative to the second welding surface 414 of the second protrusion 413, thereby avoiding the problem of poor soldering when the second pole post 40 and the conductors (such as pins or tabs) inside the energy storage device 1000 are soldered.

[0139] Please refer to Figures 10, 11 and 13. Figure 13 is a cross-sectional view of the end cap assembly shown in Figure 10.

[0140] The lower plastic 20 and the end cap 10 are stacked along the Z-axis and are connected by ultrasonic welding. The first pole post through hole 25 of the lower plastic 20 communicates with and is coaxially arranged with the first through hole 15 of the end cap 10. The opening of the first relief groove 23 of the lower plastic 20 is opposite to the end cap 10, and a first gap H1 is formed between the third groove bottom wall 232 of the first relief groove 23 and the second surface 12 of the end cap 10 around the first through hole 15. The first gap H1 communicates with and is coaxially arranged with the first pole post through hole 25. The second pole post through hole 26 of the lower plastic 20 communicates with and is coaxially arranged with the second through hole 16 of the end cap 10. The opening of the second clearance groove 24 of the lower plastic 20 is opposite to the end cap 10, and a second gap H2 is formed between the fourth groove bottom wall 242 of the second clearance groove 24 and the second surface 12 of the end cap 10 around the second through hole 16. The second gap H2 communicates with the second pole post through hole 26 and the second through hole 16. A limiting post 27 of the lower plastic 20 is accommodated in a limiting groove 17 of the end cap 10 to limit and fix the lower plastic 20 to the end cap 10.

[0141] The first electrode post 30, the second electrode post 40, the first sealing ring 50, and the second sealing ring 60 are mounted together on the lower plastic 20 and the end cap 10 to form the end cap assembly 100. The first electrode post 30 passes through the first sealing hole 50a of the first sealing ring 50, and together with the first sealing ring 50, passes through the first electrode post through hole 25 of the lower plastic 20 and the first through hole 15 of the end cap 10. The first sealing ring 50 is interference-fitted with the end cap 10, the lower plastic 20, and the first electrode post 30.

[0142] The first sealing ring 50 is fitted around the outer periphery of the first pole body 31, and then together with the first pole 30, is mounted on the end cap 10 and the lower plastic part 20. The first flange 32 of the first pole 30, the lower plastic part 20, the end cap 10, and the first folding part 33 together clamp the first sealing ring 50, and the end cap 10, the lower plastic part 20, and the first pole 30 compress the first sealing ring 50. The portion of the first sealing ring 50 clamped between the lower plastic part 20 and the end cap 10 extends into the first gap H1. The mating relationship after assembly is described below, and the specific assembly sequence will be described later. The first sealing ring 50 is located between the first flange 32 and the first folding part 33. The portion of the end cap 10 around the first through hole 15 is located between the first section 51 and the third section 53 of the first sealing ring 50. The end cap 10, the first section 51, and the third section 53 are clamped by the first folding part 33 and the first flange 32.

[0143] Specifically, the first segment 51 of the first sealing ring 50 is connected to the first connecting surface 321 of the first flange 32 and the first surface 11 of the end cap 10. The first segment 51 is interference-fitted with the end cap 10 and the first flange 32, which not only seals the assembly gap between the first flange 32 and the end cap 10, effectively preventing electrolyte splashed from the outside of the energy storage device 1000 from seeping into the interior of the first electrode post 30 through the assembly gap, thus improving the reliability of the end cap assembly 100, but also insulates the first flange 32 and the end cap 10. When the first electrode post 30 and the first sealing ring 50 are assembled to the end cap 10, the first flange 32 and the end cap 10 compress the first segment 51, causing the first segment 51 to deform and extend to both ends in its width direction (i.e., the end connected to the second segment 52 and the end away from the second segment 52). The outer peripheral surface of the first segment 51 protrudes from the outer peripheral surface of the first flange 32 to increase the creepage distance from the end cap 10 to the first electrode post 30, ensuring the safety and reliability of the end cap assembly 100.

[0144] The second segment 52 of the first sealing ring 50 is connected to the first peripheral side 312 of the first electrode body 31 and the wall of the second through hole 16 of the end cap 10, and is press-fitted with the end cap 10 and the first electrode body 31 to seal and insulate between the first electrode body 31 and the end cap 10, effectively preventing electrolyte from seeping into the interior of the first electrode 30 from the assembly gap, and improving the reliability of the end cap assembly 100. The second segment 52 may or may not be compressed, and this application does not limit this.

[0145] The third segment 53 of the first sealing ring 50 is connected to the first sealing surface 331 of the first folded portion 33 and the second surface 12 of the end cap 10, and is press-fitted with the end cap 10 and the first folded portion 33 to seal and insulate the first folded portion 33 from the end cap 10, effectively preventing electrolyte from seeping into the interior of the first electrode post 30 from the assembly gap, and improving the reliability of the end cap assembly 100. In addition, when the first electrode post 30 and the first sealing ring 50 are assembled to the end cap 10, the first folded portion 33 and the end cap 10 compress the third segment 53, causing the third segment 53 to deform and extend to both ends in its width direction (i.e., the end connected to the second segment 52 and the end away from the second segment 52). The third segment 53 is squeezed into the second gap H2 between the first relief groove 23 of the lower plastic 20 and the end cap 10, and connects the bottom wall 232 of the third groove of the first relief groove 23 and the second surface 12 of the end cap 10. The outer peripheral surface of the first folded portion 33 is opposite to the wall of the first electrode through hole 25 of the lower plastic 20 and has a certain assembly gap. It can be understood that the outer peripheral surface of the third segment 53 protrudes from the outer peripheral surface of the first folded portion 33. The third segment 53 can cover the assembly gap between the outer peripheral surface of the first folded portion 33 and the wall of the first electrode through hole 25 of the lower plastic 20, preventing metal powder from existing in the assembly gap and causing a short circuit between the end cap 10 and the first electrode 30, thus improving the voltage withstand capability of the end cap assembly 100. In some embodiments, the third segment 53 can also be squeezed into the assembly gap to seal the first electrode 30 and the lower plastic 20, further increasing the sealing performance of the end cap assembly 100 and improving its reliability.

[0146] The second electrode post 40 passes through the second sealing hole 60a of the second sealing ring 60, and together with the second sealing ring 60, passes through the second electrode post through hole 26 of the lower plastic 20 and the second through hole 16 of the end cap 10. The second sealing ring 60 is interference-fitted with the end cap 10, the lower plastic 20, and the second electrode post 40.

[0147] The second sealing ring 60 is fitted around the outer periphery of the second pole body 41, and then together with the second pole 40, is mounted on the end cap 10 and the lower plastic part 20. The second flange 42 of the second pole 40, the lower plastic part 20, the end cap 10, and the second folding part 43 together clamp the second sealing ring 60, and the end cap 10, the lower plastic part 20, and the second pole 40 compress the second sealing ring 60. The portion of the second sealing ring 60 clamped between the lower plastic part 20 and the end cap 10 extends into the second gap H2. The mating relationship after assembly is described below, and the specific assembly sequence will be described later. The second sealing ring 60 is located between the second flange 42 and the second folding part 43. The portion of the end cap 10 around the second through hole 16 is located between the fourth segment 61 and the sixth segment 63 of the second sealing ring 60. The end cap 10, the fourth segment 61, and the sixth segment 63 are clamped by the second folding part 43 and the second flange 42.

[0148] Specifically, the fourth segment 61 of the second sealing ring 60 is connected to the second connecting surface 421 of the second flange 42 and the second surface 12 of the end cap 10. The fourth segment 61 is interference-fitted with the end cap 10 and the second flange 42, which not only seals the assembly gap between the second flange 42 and the end cap 10, effectively preventing electrolyte splashed from the outside of the energy storage device 1000 from seeping into the interior of the first electrode post 30 through the assembly gap, thus improving the reliability of the end cap assembly 100, but also insulates the second flange 42 and the end cap 10. When the second electrode post 40 and the second sealing ring 60 are assembled to the end cap 10, the second flange 42 and the end cap 10 compress the fourth segment 61, causing the fourth segment 61 to deform and extend towards both ends in its width direction (i.e., the end connected to the fifth segment 62 and the end away from the fifth segment 62). The outer peripheral surface of the fourth segment 61 protrudes from the outer peripheral surface of the second flange 42 to increase the creepage distance from the end cap 10 to the second electrode post 40, ensuring the safety of the end cap assembly 100.

[0149] The fifth segment 62 of the second sealing ring 60 is connected to the second peripheral side 412 of the second electrode body 41 and the wall of the second through hole 16 of the end cap 10, and is press-fitted with the end cap 10 and the second electrode body 41 to seal and insulate between the second electrode body 41 and the end cap 10, effectively preventing electrolyte from seeping into the interior of the first electrode 30 from the assembly gap, and improving the reliability of the end cap assembly 100. The fifth segment 62 may or may not be compressed, and this application does not limit this.

[0150] The sixth segment 63 of the second sealing ring 60 is connected to the third surface of the second folded portion 43 and the second surface 12 of the end cap 10, and is press-fitted with the end cap 10 and the second folded portion 43 to seal and insulate the second folded portion 43 from the end cap 10, effectively preventing electrolyte from seeping into the first electrode post 30 from the assembly gap, and improving the reliability of the end cap assembly 100. In addition, when the second electrode post 40 and the second sealing ring 60 are assembled to the end cap 10, the second folded portion 43 and the end cap 10 compress the sixth segment 63, causing the sixth segment 63 to deform and extend to both ends in its width direction (i.e., the end connected to the fifth segment 62 and the end away from the fifth segment 62). The sixth segment 63 is squeezed into the second gap H2 between the second relief groove 24 of the lower plastic 20 and the end cap 10, and connects the fourth groove bottom wall 242 of the second relief groove 24 and the second surface 12 of the end cap 10. The outer peripheral surface of the second folded portion 43 is opposite to the wall of the second electrode through hole 26 of the lower plastic 20 and has a certain assembly gap. It can be understood that the outer peripheral surface of the sixth segment 63 protrudes from the outer peripheral surface of the second folded portion 43. The sixth segment 63 can cover the assembly gap between the outer peripheral surface of the second folded portion 43 and the wall of the second electrode through hole 26 of the lower plastic 20, preventing metal powder from existing in the assembly gap and causing a short circuit between the end cap 10 and the second electrode 40, thus improving the voltage withstand capability of the end cap assembly 100. In some embodiments, the sixth segment 63 can also be squeezed into the assembly gap to seal the second electrode 40 and the lower plastic 20, further increasing the sealing performance of the end cap assembly 100.

[0151] Please refer to Figures 14, 15a, and 15b. Figure 14 is an exploded view of a portion of the end cap assembly shown in Figure 13. Figure 15a is a structural diagram showing the first post with a first sealing ring and the second post with a second sealing ring before assembly, fitting with the end cap and the lower plastic. Figure 15b is a structural diagram showing the first post with a first sealing ring and the second post with a second sealing ring after assembly, fitting with the end cap and the lower plastic. It should be noted that Figure 15a is a cross-sectional view of the first and second posts before the flange operation, and Figure 15b is a cross-sectional view of a portion of the end cap assembly shown in Figure 14.

[0152] In this embodiment, the first pole post 30, the second pole post 40, the first sealing ring 50, and the second sealing ring 60 are first assembled with the end cover 10. The first pole post 30 passes through the first sealing hole 50a of the first sealing ring 50, and together with the first sealing ring 50, passes through the first through hole 15 of the end cover 10 from top to bottom along the Z-axis direction, as shown in Figures 14 and 15a.

[0153] When the third segment 53 of the first sealing ring 50 is not installed on the end cap 10 and the lower plastic 20, it extends along the axial direction of the first sealing ring 50, that is, the extension direction of the third segment 53 is the same as the extension direction of the second segment 52. Figure 13 shows the first sealing ring 50 in its assembled form. For ease of description, both the first sealing ring 50 before and after assembly are referred to as the first sealing ring 50. The structure of the first sealing ring 50 is described in its assembled form.

[0154] When the first pole post 30 is not installed on the end cap 10 and the lower plastic 20, it is in a state where the flange operation has not been performed, and it does not have the first folded portion 33. The first pole post 30 here can be understood as the first pole post 30 before assembly, while the first pole post 30 shown in Figure 14 can be understood as the form after assembly. For ease of description, the first pole post 30 before assembly and the first pole post 30 after assembly are uniformly referred to as the first pole post 30. The first pole post 30 before assembly includes a first folded portion base 33a. The first folded portion base 33a surrounds the periphery of the first pole post body 31 and protrudes from the first mounting surface 311 of the first pole post body 31.

[0155] The first folded portion base 33a can be formed by a flanging operation. The first outer ring surface of the first folded portion base 33a faces away from the first groove 35. The first inner ring surface of the first folded portion base 33a is set at an angle to the first mounting surface 311 of the first pole post body 31, and together with the outer peripheral surface of the first protrusion 313, forms the surface of the groove sidewall of the first groove 35.

[0156] Referring again to Figure 15a, the third segment 53 of the first sealing ring 50 is connected to the first outer annular surface of the first folded portion base 33a, and the third segment 53 and the first folded portion base 33a extend in the same direction; and the length of the third segment 53 protruding from the end cap 10 is greater than or equal to the length of the first folded portion base 33a protruding from the end cap 10, so that the first sealing ring 50 can sufficiently separate the first pole post 30 and the end cap 10. The first sealing ring 50 and the first pole post 30 are installed on the end cap 10 and the lower plastic 20, and the specific fit can be referred to Figure 13 and the above description. In some embodiments, while ensuring that the third segment 53 can sufficiently separate the first pole post 30 and the end cap 10 after being compressed, the length of the third segment 53 protruding from the end cap 10 can also be less than the length of the first folded portion base 33a protruding from the end cap 10, which can save certain costs.

[0157] As shown in Figure 15b, a flanging operation is performed on the first folded portion base 33a, flipping the first folded portion base 33a in the direction away from the axis O1-O1 of the first pole post 30, and flipping the first folded portion 33a so that it is perpendicular to the axis OO of the first pole post 30, to form the first folded portion 33. At this time, the first folded portion 33 presses the third segment 53 onto the end cap 10, and the third segment 53 connects the first sealing surface 331 of the first folded portion 33 and the second surface 12 of the end cap 10. The third segment 53 deforms under the pressure of the first folded portion 33 and extends to both ends in its width direction. The outer peripheral surface of the third segment 53 protrudes from the outer peripheral surface of the first folded portion 33 and is squeezed into the first gap H1 to cover the assembly gap between the lower plastic 20 and the first pole post 30, preventing metal powder from existing in the assembly gap and causing a short circuit between the end cap 10 and the first pole post 30, thereby improving the voltage withstand capability of the end cap assembly 100.

[0158] The first outer surface 332 of the first folded portion 33 protrudes from the first mounting surface 311 of the first pole body 31, and the first outer surface 332 is recessed from the first welding surface 314 of the first protrusion 313 to prevent poor soldering when the first pole 30 is soldered to conductors (such as pins or tabs) inside the energy storage device 1000. A crease is formed between the first folded portion 33 and the first protrusion 313. In some embodiments, along the direction from the lower plastic 20 to the end cap 10, the first folded portion base 33a can be flipped to form an obtuse angle with the axis O1-O1 of the first pole 30.

[0159] The second pole post 40 passes through the second sealing hole 60a of the second sealing ring 60, and together with the second sealing ring 60, passes through the second through hole 16 of the end cover 10 from top to bottom along the Z-axis direction, as shown in Figures 14 and 15a.

[0160] When the sixth segment 63 of the second sealing ring 60 is not installed on the end cap 10 and the lower plastic 20, it extends along the axial direction of the second sealing ring 60, that is, the extension direction of the sixth segment 63 is the same as the extension direction of the fifth segment 62. Figure 13 shows the assembled form of the second sealing ring 60. For ease of description, both the unassembled and assembled second sealing ring 60 are referred to as the second sealing ring 60. The structure of the second sealing ring 60 is described based on its assembled form.

[0161] When the second pole post 40 is not installed on the end cap 10 and the lower plastic 20, it is in a state where the flange operation has not been performed, and it does not have the second folded portion 43. The second pole post 40 here can be understood as the second pole post 40 before assembly, while the second pole post 40 shown in Figure 14 can be understood as the form after assembly. For ease of description, the second pole post 40 before assembly and the second pole post 40 after assembly are uniformly referred to as the second pole post 40. The second pole post 40 before assembly includes a second folded portion base 43a. The second folded portion base 43a surrounds the periphery of the second pole post body 41 and protrudes from the second mounting surface 411 of the second pole post body 41.

[0162] The second folded portion base 43a can be formed by a flanging operation. The second outer ring surface 441 of the second folded portion base 43a faces away from the second groove 45. The second inner ring surface 442 of the second folded portion base 43a is set at a 90-degree angle to the second mounting surface 411 of the second pole post body 41, and together with the outer peripheral surface of the second protrusion 413, forms the surface of the groove sidewall of the second groove 45.

[0163] Referring again to Figure 15a, the sixth segment 63 of the second sealing ring 60 is connected to the second outer annular surface 441 of the second folded portion base 43a. The sixth segment 63 and the second folded portion base 43a extend in the same direction; and the length of the sixth segment 63 protruding from the end cap 10 is greater than or equal to the length of the second folded portion base 43a protruding from the end cap 10, so that the second sealing ring 60 can sufficiently separate the second pole post 40 and the end cap 10. The second sealing ring 60 and the second pole post 40 are installed on the end cap 10 and the lower plastic 20. For specific fitting, please refer to Figure 13 and the above description. In some embodiments, while ensuring that the sixth segment 63 can sufficiently separate the second pole post 40 and the end cap 10 after compression, the length of the sixth segment 63 protruding from the end cap 10 can also be less than the length of the second folded portion base 43a protruding from the end cap 10, which can save certain costs.

[0164] As shown in Figure 15b, a flanging operation is performed on the second folded portion base 43a, flipping the second folded portion base 43a in the direction away from the axis O2-O2 of the second pole post 40, and flipping it so that it is perpendicular to the axis O2-O2 of the second pole post 40, to form the second folded portion 43. At this time, the second folded portion 43 presses the sixth segment 63 onto the end cap 10, and the sixth segment 63 connects the second sealing surface 431 of the second folded portion 43 and the second surface 12 of the end cap 10. Under the pressure of the second folded portion 43, the sixth segment 63 deforms and extends to both ends in its width direction. The outer peripheral surface of the sixth segment 63 protrudes from the outer peripheral surface of the second folded portion 43 and is squeezed into the second gap H2 to cover the assembly gap between the lower plastic 20 and the second pole post 40, preventing metal powder from existing in the assembly gap and causing a short circuit between the end cap 10 and the second pole post 40, thereby improving the voltage withstand capability of the end cap assembly 100.

[0165] The second outer surface 432 of the second folded portion 43 protrudes from the second mounting surface 411 of the second pole body 41, and the second outer surface 432 is recessed from the second welding surface 414 of the second protrusion 413 to prevent poor soldering when the second pole 40 is soldered to conductors (such as pins or tabs) inside the energy storage device 1000. The creases of the second folded portion 43 and the second protrusion 413 are visible. In some embodiments, along the direction from the lower plastic 20 to the end cap 10, the second folded portion base 43a can be flipped to form an obtuse angle with the axis O2-O2 of the second pole 40.

[0166] Please refer to Figures 13 and 16. Figure 16 is a partial structural exploded view of the end cap assembly shown in Figure 10.

[0167] It should be noted that Figure 16 shows the assembled end cap 10, first pole post 30, second pole post 40, first sealing ring 50, and second sealing ring 60 shown in Figure 15a, assembled together with the lower plastic 20 to form the end cap assembly 100. Along the Z-axis, the top surface 21 of the lower plastic 20 is opposite to the second surface 12 of the end cap 10, and the limiting post 27 of the lower plastic 20 is directly opposite the groove opening of the limiting groove 17 of the end cap 10. The first pole post through hole 25 of the lower plastic 20 is opposite to and coaxially arranged with the first through hole 15 of the end cap 10. The first pole post 30 passes through the first pole post through hole 25 of the lower plastic 20, and the outer peripheral surface of the first folded portion 33 is opposite to and spaced apart from the hole wall of the first pole post through hole 25. The third segment 53 of the first sealing ring 50 protrudes from the first folded portion 33 and is accommodated in the first relief groove 23, and is connected to the third groove bottom wall 232 of the first relief groove 23 and the second surface 12 of the end cap 10. The second electrode through-hole 26 of the lower plastic 20 is opposite to and coaxially arranged with the second through-hole 16 of the end cap 10. The second electrode 40 passes through the second electrode through-hole 26 of the lower plastic 20, and the outer peripheral surface of the second folded portion 43 is opposite to and spaced apart from the hole wall of the second electrode through-hole 26. The sixth segment 63 of the second sealing ring 60 protrudes from the second folded portion 43 and is accommodated in the second relief groove 24, and is connected to the fourth groove bottom wall 242 of the second relief groove 24 and the second surface 12 of the end cap 10.

[0168] In related technologies, the sealing structure in the end cap assembly 100 is complex. For example, the end cap assembly 100 includes upper plastic, lower plastic, and sealing rings, among other sealing components. The sealing performance of these components deteriorates at low temperatures, and they are prone to failure. This not only reduces the reliability of the end cap assembly 100 but also makes it easier for electrolyte from outside the energy storage device 1000 to seep into the electrode post, and for electrolyte inside the energy storage device 1000 to backflow and form white crystals, affecting the appearance of the energy storage device 1000. For instance, the sealing components in existing end cap assemblies 100 are generally made of fluororubber. Fluororubber is prone to embrittlement at low temperatures (-40°C), causing the sealing performance of the end cap assembly 100 to fail and resulting in defects in the energy storage device 1000.

[0169] In this embodiment, the end cap assembly 100 has a simple structure, requiring only a first sealing ring 50 and a second sealing ring 60 as sealing components. This eliminates the need for plastic coating, saving manufacturing costs and simplifying the structure. Both the first sealing ring 50 and the second sealing ring 60 are made of low-temperature resistant and electrolyte-resistant rubber synthetic materials such as EPDM, ensuring good sealing performance even at low temperatures and improving the reliability of the end cap assembly 100.

[0170] Furthermore, the first fold 33 and the first flange 32 of the first electrode post 30 tightly compress the first sealing ring 50, achieving a good seal between the first electrode post 30 and the end cap 10 without welding, preventing electrolyte from entering the first electrode post 30 through the assembly gap between the first electrode post 30 and the end cap 10. Similarly, the second fold 43 and the second flange 42 of the second electrode post 40 tightly compress the second sealing ring 60, achieving a good seal between the second electrode post 40 and the end cap 10 without welding, preventing electrolyte from entering the second electrode post 40 through the assembly gap between the second electrode post 40 and the end cap 10. Therefore, the end cap assembly 100 in this application has a good appearance and low manufacturing cost.

[0171] The above are merely some embodiments and implementation methods of this application. The scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An end cap assembly, wherein, include: An end cap, wherein the end cap is provided with a through hole that penetrates two surfaces of the end cap in the thickness direction; The lower plastic includes an electrode through hole that penetrates two surfaces of the lower plastic in the thickness direction. The lower plastic and the end cap are stacked along the thickness direction of the end cap assembly. The through hole communicates with the electrode through hole. An electrode post, comprising an electrode post body and a flange, the flange being connected to one end of the electrode post body in the height direction, the electrode post body including a mounting surface facing away from the flange, the electrode post further including a folded portion, the folded portion protruding from the periphery of one end of the electrode post body and surrounding the mounting surface, the folded portion and the flange being opposite to and spaced apart along the height direction of the electrode post, the folded portion including an outer surface facing away from the flange and connected to the mounting surface, the outer surface and the mounting surface having a crease, the outer surface being flush with the mounting surface, or, along the direction from the folded portion to the flange, the mounting surface protruding from the outer surface; and A sealing ring is fitted around the outer periphery of the pole body and passes through the through hole and the pole through hole together with the pole. The end cap portion around the through hole is located between the flange and the folded part. The flange, the lower plastic, the end cap and the folded part together clamp the sealing ring, and the end cap, the lower plastic and the pole compress the sealing ring.

2. The end cap assembly according to claim 1, wherein, The lower plastic includes a bottom surface and a top surface, the top surface and the bottom surface are arranged opposite to each other along the thickness direction of the lower plastic, the lower plastic includes a relief groove, the relief groove is recessed in the top surface and recessed in the bottom surface, and the pole through hole penetrates the bottom wall of the relief groove; The end cap includes a first surface and a second surface, which are arranged opposite to each other along the thickness direction of the end cap, and the through hole penetrates the second surface and the first surface; The opening of the clearance groove is opposite to the end cap, and there is a gap between the bottom wall of the clearance groove and the second surface of the end cap around the through hole, and the gap communicates with the pole post through hole and the through hole. The portion of the sealing ring sandwiched between the lower plastic and the end cap extends into the gap.

3. The end cap assembly according to claim 2, wherein, The sealing ring includes a first segment, a second segment, and a third segment. The second segment is connected to the first segment and the third segment. The second segment extends along the axial direction of the sealing ring. The third segment and the first segment both extend away from the axial direction of the sealing ring. The first segment and the third segment are both straight segments. The second segment is connected to the pole body and the end cap. The end cap around the pole is located between the first segment and the third segment. The end cap, the first segment, and the third segment are clamped by the folding part and the flange. The third segment is at least partially accommodated in the gap and covers the assembly gap between the pole and the lower plastic.

4. The end cap assembly according to claim 3, wherein, The contact area between the third segment and the end cap is greater than the contact area between the first segment and the end cap.

5. The end cap assembly according to claim 3, wherein, The flange protrudes from the bottom surface of the lower plastic, and the folded portion is located on the side of the end cap facing away from the lower plastic; The first segment is sandwiched between the folded portion and the end cap, and the outer peripheral surface of the first segment protrudes beyond the outer peripheral surface of the folded portion. The third segment is sandwiched between the flange and the end cap, and the outer peripheral surface of the third segment protrudes beyond the outer peripheral surface of the flange.

6. The end cap assembly according to claim 3, wherein, The outer surface of the folded part faces the same direction as the bottom surface of the lower plastic, and the flange is located on the side of the end cap facing away from the lower plastic; The first segment is clamped between the flange and the end cap, and the outer peripheral surface of the first segment protrudes from the outer peripheral surface of the flange. The third segment is clamped between the folded portion and the end cap, and the outer peripheral surface of the third segment protrudes from the outer peripheral surface of the folded portion.

7. The end cap assembly according to claim 3, wherein, The end cap also includes a sealing groove, which is recessed on the second surface of the end cap and recessed towards the first surface. The through hole penetrates the bottom wall of the sealing groove. The opening of the clearance groove is opposite to the opening of the sealing groove. The gap is formed between the bottom wall of the clearance groove and the bottom wall of the sealing groove. The gap communicates with the through hole of the pole post and the through hole. The third segment is connected to the bottom wall of the sealing groove and the bottom wall of the clearance groove.

8. The end cap assembly according to any one of claims 3-7, wherein, The first segment has a first compression amount after compression, and the third segment has a second compression amount after compression. The sum of the first compression amount and the second compression amount is 5% to 55% of the sum of the thickness of the first segment and the third segment before compression.

9. The end cap assembly according to claim 3, wherein, The flange includes a connecting surface that surrounds and connects to the pole body. The flange also includes a step located on the outer circumferential surface of the flange and recessed in the connecting surface. The step includes a mounting surface that faces the same direction as the connecting surface and abuts against the bottom surface of the lower plastic.

10. The end cap assembly according to claim 1, wherein, The pole post also includes a protrusion, which protrudes from the mounting surface of the pole post body and is located at the center of the mounting surface. Along the axis perpendicular to the pole post, the protrusion and the folded portion are spaced apart.

11. A method for manufacturing an end cap assembly, used to manufacture the end cap assembly according to any one of claims 1-10, wherein, The manufacturing method includes: Provide a sealing ring before assembly, and provide the extension direction of the first segment and the extension direction of the second segment of the sealing ring before assembly; A pre-assembly pole is provided. The mounting surface of the pre-assembly pole body has a protrusion. The pre-assembly pole includes a folded portion base. The folded portion base is arranged around the periphery of the pole body and protrudes from the mounting surface of the pole body. A groove is formed between the folded portion base and the protrusion. The folded portion includes an inner ring surface. The inner ring surface is connected to the mounting surface and is arranged at an angle to the mounting surface. The extending direction of the folded portion base is the same as the axial direction of the pre-assembly pole. The lower plastic and the end cap are stacked together, and the through hole of the pole post of the lower plastic and the through hole of the end cap are coaxial and connected. Before assembly, the pole is inserted through the sealing ring before assembly, and passes through the pole through hole and the through hole in sequence with the sealing ring before assembly. The flange protrudes from the lower plastic. The third section is clamped between the end cap and the flange. The folded part base and the first section protrude from the end cap. The first section extends in the same direction as the folded part base. The second section connects between the end cap and the pole body. The folding base is flipped away from the end cap, and the first segment is pressed against the end cap, so that the folding base forms the folding portion, the inner ring surface forms the outer surface, the folding portion and the end cap hold the first segment, and the outer surface is flush with the mounting surface.

12. An energy storage device, wherein, It includes a housing, an electrode assembly, and an end cap assembly as described in any one of claims 1-10, wherein the electrode assembly is mounted on the housing, and the end cap assembly is mounted on one end of the electrode assembly and seals the housing.

13. An electrical appliance, wherein, It includes the energy storage device as described in claim 12, wherein the energy storage device supplies power to the electrical equipment.

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