End cap assembly, energy storage device and electric device

Abstract

Disclosed in the present application are an end cap assembly, an energy storage device and an electric device. The end cap assembly comprises an end plate, a terminal post and a connector, wherein the end plate has a first surface and a second surface arranged opposite each other in the thickness direction thereof; the end plate further has a first terminal post hole penetrating therethrough; a terminal post comprises a first post section and a second post section, an outer peripheral surface of the first post section being connected to an outer peripheral surface of the second post section by means of an annular step face, and the first post section passing through the first terminal post hole; the connector is located on the side of the terminal post where the annular step face is located, and has a second terminal post hole provided coaxially with the first terminal post hole, and the second post section passes through the second terminal post hole and is connected to the connector; a first groove is provided on the side of the connector facing the annular step face, and the first groove is in communication with the second terminal post hole; and the orthographic projections of the first groove and of the annular step face on the plane where the first surface is located have an overlapping area, and part of the first projection of the first groove extends from an outer contour line of the second projection of the annular step face. (FIG. 5)

Description

End cap assemblies, energy storage devices and electrical equipment

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 2024216312233, filed on July 10, 2024, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] This application relates to the field of energy storage technology, and more specifically, to an end cap assembly, an energy storage device including the end cap assembly, and an electrical device including the energy storage device. Background Technology

[0004] In related technologies, the end cap assembly of a battery needs to undergo airtightness testing during manufacturing to ensure the safety and lifespan of the battery during use. However, during the pressing and assembly of the terminal post assembly in related technologies, the airtightness requirements may be temporarily met (i.e., a "false seal") due to the close contact between relatively rigid components. This may result in the product passing the airtightness test and being put into use. However, during subsequent long-term use, due to fluctuations in ambient temperature, rigid components such as metal terminals and plastic insulation components have different expansion and contraction rates due to their different materials. This can lead to shrinkage gaps at the contact surfaces, causing air leakage and posing a serious safety hazard.

[0005] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] This application provides an end cap assembly, an energy storage device, and an electrical device that can improve the accuracy of airtightness testing, thereby solving the problems existing in related technologies.

[0007] The end cap assembly of this application embodiment is used for an energy storage device, including:

[0008] An end plate has a first surface and a second surface disposed opposite to each other along its thickness direction; the end plate also has a first pole hole that penetrates the first surface and the second surface.

[0009] An electrode post has a first segment and a second segment along its axial direction. The cross-sectional area of ​​the first segment is larger than that of the second segment. The outer peripheral surfaces of the first and second segments are connected by an annular stepped surface. The first segment passes through a hole in the first electrode post.

[0010] A connector is located on the side of the annular stepped surface of the pole post, and has a second pole post hole coaxially arranged with the first pole post hole. The second pole segment passes through the second pole post hole and is connected to the connector. The connector has at least one first groove on the side facing the annular stepped surface, and the first groove communicates with the second pole post hole.

[0011] Wherein, the orthographic projection of the first groove on the plane where the first surface is located is the first projection, and the orthographic projection of the annular step surface on the plane where the first surface is located is the second projection. The first projection and the second projection have an overlapping area, and a portion of the first projection extends beyond the outer contour line of the second projection.

[0012] The energy storage device according to the embodiments of this application includes:

[0013] The housing includes a receiving cavity with an opening;

[0014] Electrode assembly, housed within the receiving cavity; and

[0015] The end cap assembly according to any of the preceding claims, wherein the end cap assembly closes the opening of the receiving cavity.

[0016] The electrical equipment in this application embodiment includes the energy storage device described above, and the energy storage device supplies power to the electrical equipment. Attached Figure Description

[0017] Figure 1 shows a schematic diagram of a residential energy storage system.

[0018] Figure 2 shows an exploded view of a single cell according to an embodiment of this application.

[0019] Figure 3 shows an exploded view of the end cap assembly according to an embodiment of this application.

[0020] Figure 4 shows a top view of the end cap assembly according to an embodiment of this application.

[0021] Figure 5 shows a partial cross-sectional view along section line AA in Figure 4.

[0022] Figure 6 shows a schematic diagram of the connector according to an embodiment of this application.

[0023] Figure 7 shows a schematic diagram of the positional relationship between the first projection and the second projection.

[0024] Figure 8 shows a schematic diagram of the upper insulating member according to an embodiment of this application.

[0025] Figure 9 shows a schematic diagram of the lower insulating member according to an embodiment of this application.

[0026] Figure 10 shows a schematic diagram of the positional relationship between the third and fourth projections.

[0027] Figure 11 shows a schematic diagram of the seal according to an embodiment of this application.

[0028] Figure 12 shows a schematic diagram of the positional relationship between the first projection and the fifth projection.

[0029] Figure 13 shows another schematic diagram of the positional relationship between the first projection and the fifth projection.

[0030] Figure 14 shows a schematic diagram of the electrical equipment according to an embodiment of this application.

[0031] The reference numerals in the attached drawings are explained as follows: 1. Energy storage device; 2. Power conversion device; 3. User load; 4. Electrical equipment; 10. Housing; 11. Receiving cavity; 12. Opening; 20. Electrode assembly; 30. End cap assembly; 100. End plate; 101. First surface; 102. Second surface; 103. First pole post hole; 104. Lower groove; 105. Vent hole; 106. Liquid injection hole; 200. Pole post; 210. First column segment; 220. Second column segment; 230. Third column segment; 240. Annular stepped surface; 300. Upper insulating component; 310. First annular portion; 320. Second annular portion; 321. Second groove; 330. Third annular portion; 400. Lower insulating component; 401. Third pole post hole; 410. Annular flange; 411. Third groove; 420. Insulating sheet; 421. Through hole; 430. Fourth annular part; 500. Connector; 501. Second pole hole; 510. First groove; 600. Seal; 610. Sealing ring; 620. Protrusion; 700. Explosion-proof valve; 800. Protective plate. Detailed Implementation

[0032] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that this application will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore their detailed description will be omitted.

[0033] It is understood that the terms "comprising" and "having," and any variations thereof, in the embodiments of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or components inherent to these processes, methods, products, or devices.

[0034] Since the energy people need is highly time- and space-dependent, in order to make rational use of energy and improve energy efficiency, it is necessary to use a medium or device to store one form of energy in the same way or by converting it into another form of energy, and then release it in a specific form of energy based on future application needs.

[0035] Current energy storage applications are quite widespread, including generation-side energy storage, grid-side energy storage, renewable energy grid-connected energy storage, and user-side energy storage. The corresponding types of energy storage devices include:

[0036] (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.

[0037] (2) Small and medium-sized energy storage cabinets used in commercial and industrial energy storage scenarios (banks, shopping malls, etc.) and small household energy storage boxes used in residential energy storage scenarios primarily operate under the "peak shaving and valley filling" mode. Because there are significant price differences in electricity consumption during peak and off-peak periods, users with energy storage devices typically charge the cabinets / boxes during off-peak hours to reduce costs; during peak hours, they release the stored electricity for use, thus saving on electricity bills. Furthermore, in remote areas and regions prone to natural disasters such as earthquakes and hurricanes, the existence of household energy storage devices effectively provides backup power for users and the power grid, eliminating the inconvenience caused by frequent power outages due to disasters or other reasons.

[0038] Taking a residential energy storage scenario in user-side energy storage as an example, Figure 1 illustrates a residential energy storage system. This system includes an energy storage device 1, a power conversion device 2 (such as a photovoltaic panel), and user loads 3 (such as streetlights, household appliances, etc.). The energy storage device 1 is a small energy storage box that can be wall-mounted on an outdoor wall. Specifically, the power conversion device 2 can convert solar energy into electrical energy during periods of low electricity prices and store it through the energy storage device 1. This stored energy can then be supplied to the user loads 3 during periods of high electricity prices, or during power outages / power interruptions.

[0039] In conjunction with the aforementioned energy storage methods using physical or electrochemical means, taking electrochemical energy storage as an example, the energy storage device 1 includes at least one set of chemical batteries. The chemical elements within these batteries serve as the energy storage medium, and the charging and discharging process is achieved through the chemical reactions or changes in the storage medium. Simply put, electrical energy generated from solar or wind power is stored in at least one set of chemical batteries through the chemical reactions or changes in the storage medium. When external power consumption reaches its peak, the stored energy is released through the chemical reactions or changes in the storage medium for use, or transferred to areas with power shortages.

[0040] This application provides an energy storage device 1, which can be, but is not limited to, a single battery (secondary battery), a battery module, a battery pack, or a battery system composed of single batteries. The single battery can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and can be cylindrical, flat, cuboid, etc. This application does not limit the form of the single battery. The following explanation uses a cuboid single battery as an example to illustrate the energy storage device 1.

[0041] As shown in Figure 2, the energy storage device 1 of this application embodiment includes a housing 10, an electrode assembly 20, and an end cap assembly 30. The housing 10 includes a receiving cavity 11 with an opening 12, the electrode assembly 20 is housed in the receiving cavity 11, and the end cap assembly 30 is connected to the housing 10 and closes the opening 12 of the receiving cavity 11.

[0042] The housing 10 can be a cylindrical structure with an opening 12 at one end. In this case, the energy storage device 1 includes an end cap assembly 30, which seals the opening 12. Alternatively, the housing 10 can also be a cylindrical structure with openings 12 at both ends. In this case, the energy storage device 1 can include an end cap assembly 30 and a cover plate, or the energy storage device 1 can include two end cap assemblies 30. Thus, one end cap assembly 30 and a cover plate, or two end cap assemblies 30, can respectively seal the two openings 12 of the housing 10.

[0043] Optionally, the housing 10 can be a steel housing, an aluminum housing, a plastic housing (such as polypropylene), a composite metal housing (such as a copper-aluminum composite housing), or an aluminum-plastic film, etc.

[0044] The electrode assembly 20 includes a positive electrode, a negative electrode, and a separator. The single-cell battery primarily operates by the movement of metal ions between the positive and negative electrode plates. The positive electrode includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector, and the uncoated positive current collector protrudes beyond the coated positive current collector, serving as the positive electrode tab. Taking a lithium-ion battery as an example, the positive current collector can be made of aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector, and the uncoated negative current collector protrudes beyond the coated negative current collector, serving as the negative electrode tab. The negative current collector can be made of copper, and the negative active material can be carbon or silicon, etc. The material of the separator can be PP or PE, etc. In addition, the electrode assembly 20 can be a wound structure or a stacked structure, and the embodiments of this application are not limited to this.

[0045] The positive and negative electrodes can be located at the same end of the electrode assembly 20 (e.g., a square single cell) or at different ends of the electrode assembly 20 (e.g., a cylindrical single cell). When the positive and negative electrodes are located at the same end of the electrode assembly 20, the end cap assembly 30 can be provided with a positive terminal and a negative terminal, with the positive terminal connected to the positive electrode and the negative terminal connected to the negative electrode, so that the electrical energy output of the electrode assembly 20 can be realized through the positive and negative terminals. When the positive and negative electrodes are located at opposite ends of the electrode assembly 20, one of the positive and negative electrodes is connected to a terminal provided on the end cap assembly 30, and the other of the positive and negative electrodes is connected to the bottom of the housing 10 or a terminal provided on another end cap assembly 30. The terminal connected to the positive electrode is the positive terminal, and the terminal connected to the negative electrode is the negative terminal.

[0046] As shown in Figure 3, the end cap assembly 30 includes an end plate 100, an explosion-proof valve 700, and a protective plate 800. The end plate 100 is connected to the housing 10 and seals the opening 12 of the receiving cavity 11. Welding can be used to connect the end plate 100 to the housing 10, but this is not a limitation. The shape of the end plate 100 is adapted to the shape of the opening 12. In this embodiment, the opening 12 is rectangular, therefore the end plate 100 is also rectangular.

[0047] The end plate 100 has a vent 105 that extends through the end plate 100 along its thickness. An explosion-proof valve 700 is connected to the surface of the end plate 100 facing the electrode assembly 20 and seals the vent 105. The explosion-proof valve 700 is used to rupture and release the gas generated in the receiving cavity 11 of the housing 10 when the gas pressure in the energy storage device 1 reaches a certain pressure threshold, thereby preventing the battery from bulging and exploding, and thus improving the safety of the energy storage device 1.

[0048] The protective plate 800 is attached to the side of the end plate 100 facing away from the electrode assembly 20, and covers the vent hole 105 and the explosion-proof valve 700, thus protecting the explosion-proof valve 700.

[0049] The end plate 100 is also provided with an injection hole 106, which penetrates the end plate 100 along its thickness direction. After the end cap assembly 30 seals the opening 12 of the receiving cavity 11, electrolyte can be injected into the receiving cavity 11 of the housing 10 through the injection hole 106. After the electrolyte injection is completed, the injection hole 106 can be sealed with a sealing element (not shown in the figure) to prevent electrolyte leakage.

[0050] As shown in Figures 3 to 5, the end cap assembly 30 further includes a pole post 200, an upper insulating member 300, a lower insulating member 400, a connector 500, and a sealing member 600. The end plate 100 has a first surface 101 and a second surface 102 disposed opposite to each other along its thickness direction. The end plate 100 also has a first pole post hole 103, which penetrates the first surface 101 and the second surface 102. The pole post 200 is confined within the first pole post hole 103. The upper insulating member 300, the lower insulating member 400, the connector 500, and the sealing member 600 are all mounted on the end plate 100. In one embodiment, the end plate 100 is a sheet of smooth aluminum, but this is not a limitation. The upper insulating member 300 and the lower insulating member 400 are made of insulating material, such as plastic.

[0051] The lower insulating member 400 overlaps with the end plate 100 on the second surface 102 of the end plate 100 to insulate the pole post 200 from the end plate 100. The upper insulating member 300 surrounds the outer periphery of the pole post to insulate the pole post 200 from the end plate 100. The connector 500 is connected to the end of the pole post 200 that extends out of the second surface 102, for example by welding. The seal 600 seals between the end plate 100 and the connector 500.

[0052] As shown in Figures 5 and 6, the pole post 200 has a first pole segment 210 and a second pole segment 220 along its axial direction. The first pole segment 210 and the second pole segment 220 are coaxially arranged, and the cross-sectional area of ​​the first pole segment 210 is larger than that of the second pole segment 220. The outer peripheral surface of the first pole segment 210 and the outer peripheral surface of the second pole segment 220 are connected by an annular stepped surface 240. The first pole segment 210 passes through the first pole post hole 103. The connector 500 is located on the side of the pole post where the annular stepped surface 240 is located, and has a second pole post hole 501 coaxially arranged with the first pole post hole 103. The second pole segment 220 passes through the second pole post hole 501 and is connected to the connector 500. The side of the connector 500 facing the annular stepped surface 240 has at least one first groove 510, and the first groove 510 communicates with the second pole post hole 501.

[0053] As shown in Figure 7, the orthographic projection of the first groove 510 on the plane where the first surface 101 is located is the first projection S1, and the orthographic projection of the annular step surface 240 on the plane where the first surface 101 is located is the second projection S2. The first projection S1 and the second projection S2 have an overlapping area, and part of the first projection S1 extends out of the outer contour line of the second projection S2.

[0054] It should be noted that the connector 500 and the second post segment 220 of the pole post 200 are generally connected by welding. The quality of the welding position between the connector 500 and the second post segment 220 determines the sealing performance between them. If there are welding defects, such as pinholes or weld holes, the end cap assembly 30 will fail the airtightness test. However, after the connector 500 and the second post segment 220 are welded, the connector 500 may press against the annular step surface 240, at which point the annular step surface 240 and one side surface of the connector 500 form a seal. Even if there are welding defects, the end cap assembly 30 will still pass the airtightness test.

[0055] In this embodiment of the application, the end cap assembly 30 has at least one first groove 510 on the side of the connector 500 facing the annular step surface 240. If there is a welding defect at the welding position of the connector 500 and the second column segment 220, even if the connector 500 is in contact with the annular step surface 240, the welding position can still communicate with the outside through the first groove 510. In this case, the end cap assembly 30 with welding defects at the welding position cannot pass the airtightness test, thereby improving the accuracy of the airtightness test and eliminating safety hazards.

[0056] In one embodiment, the side surface of the connector 500 facing the annular step surface 240 is press-fitted with the annular step surface 240.

[0057] In this embodiment, since the connector 500 has a first groove 510, the side surface of the connector 500 facing the annular stepped surface 240 can be press-fitted with the annular stepped surface 240, so that the connector 500 and the annular stepped surface 240 of the pole post 200 are tightly pressed together. When the connector 500 and the pole post 200 are laser welded, the welding laser is less likely to penetrate through the connection between the connector 500 and the annular stepped surface 240 and burn the insulating part 300 and the sealing part 600, further improving the sealing performance of the sealing part 600.

[0058] As shown in Figure 6, the connector 500 has a plurality of first grooves 510, each first groove 510 penetrating the hole wall of the second pole hole 501 and extending radially along the second pole hole 501. The plurality of first grooves 510 are arranged at equal intervals along the circumference of the second pole hole 501.

[0059] In one embodiment, the connector 500 has four first grooves 510, but is not limited thereto.

[0060] As shown in Figures 5 and 8, the upper insulating member 300 includes a first annular portion 310, a second annular portion 320 and a third annular portion 330 connected to each other. The first annular portion 310 passes through the first pole hole 103 and surrounds the outer periphery of the first column segment 210. The second annular portion 320 and the third annular portion 330 are located on the side where the first surface 101 of the end plate 100 is located.

[0061] The pole post 200 also has a third post segment 230, which is coaxially arranged with the first post segment 210. The first post segment 210 is connected between the second post segment 220 and the third post segment 230. The cross-sectional area of ​​the third post segment 230 is larger than that of the first post segment 210. A third annular portion 330 surrounds the outer periphery of the third post segment 230, and a second annular portion 320 is disposed between the third post segment 230 and the end plate 100.

[0062] The second annular portion 320 has at least one second groove 321 on the side facing the third column segment 230, the second groove 321 extending from the inner annular surface of the first annular portion 310 to the inner annular surface of the third annular portion 330.

[0063] In this embodiment, since the second annular portion 320 has a second groove 321 on the side facing the third column segment 230, in the event of a missing seal 600 or damage to the seal 600, the spaces on both sides of the end cap assembly 30 in the thickness direction are connected through the second groove 321. In this case, the end cap assembly 30 will not pass the airtightness test, thereby further improving the accuracy of the airtightness test of the end cap assembly 30.

[0064] In one embodiment, the second annular portion 320 has a plurality of second grooves 321, each second groove 321 extending radially along the pole post 200, and the plurality of second grooves 321 are arranged at equal intervals along the circumference of the pole post.

[0065] As an example, the first groove 510 and the second groove 321 are respectively misaligned in their orthographic projections on the plane containing the first surface 101. In other words, the first groove 510 and the second groove 321 are misaligned along the axial direction of the pole post 200.

[0066] In the embodiments of this application, the first groove 510 and the second groove 321 are designed to be staggered along the axial direction of the pole post 200, which can improve the uniformity of the pressure distribution of the pole post 200, thereby avoiding the formation of weak areas by overlapping in the area where the grooves are located along the axial direction of the pole post, which can easily lead to leakage points, and improving the overall sealing performance of the end cap assembly.

[0067] As shown in Figures 5 and 9, the end plate 100 also has a recessed groove 104, which is recessed from the second surface 102 along the thickness direction of the end plate 100 toward the first surface 101, and the first pole hole 103 penetrates the bottom surface of the recessed groove 104.

[0068] The lower insulating member 400 has an insulating sheet 420, a fourth annular portion 430, and a flange. The insulating sheet 420 is located on the side of the second surface 102 of the end plate 100 and has a through hole 421. The through hole 421 penetrates the insulating sheet 420 along the thickness direction of the end plate 100. The second column segment 220 passes through the through hole 421, and the connector 500 is confined within the through hole 421.

[0069] The fourth annular portion 430 is connected to the edge of the through hole 421 and protrudes from the surface of the insulating sheet 420 facing the end plate 100. The fourth annular portion 430 is located in the recessed groove 104 and surrounds the outer periphery of the connector 500.

[0070] An annular flange 410 protrudes from the inner annular surface of the fourth annular portion 430 and is located on the side of the connector 500 facing the annular stepped surface 240, within the recessed groove 104. The annular flange 410 has a third pole post hole 401 coaxially disposed with the first pole post hole 103, and the first column segment 210 passes through the third pole post hole 401. The annular flange 410 has at least one third groove 411 on the side facing the connector 500, and the third groove 411 communicates with the third pole post hole 401. The third groove 411 extends from the hole wall of the third pole post hole 401 to the inner annular surface of the fourth annular portion 430.

[0071] As shown in Figure 10, the orthographic projection of the third groove 411 on the plane where the first surface 101 is located is the third projection S3, and the orthographic projection of the connector 500 on the plane where the first surface 101 is located is the fourth projection S4. The third projection S3 and the fourth projection S4 have an overlapping area, and part of the third projection S3 extends out of the outer contour line of the fourth projection S4.

[0072] In this embodiment, since the annular flange 410 has a third groove 411 on the side facing the connector 500, in the event of a missing seal 600 or damage to the seal 600, the spaces on both sides of the end cap assembly 30 in the thickness direction are connected through the third groove 411. In this case, the end cap assembly 30 will not pass the airtightness test, thereby further improving the accuracy of the airtightness test of the end cap assembly 30.

[0073] As shown in Figure 9, the annular flange 410 has a plurality of third grooves 411, each third groove 411 penetrating the hole wall of the third pole hole 401 and extending radially along the third pole hole 401. The plurality of third grooves 411 are arranged at equal intervals along the circumference of the third pole hole 401.

[0074] In one embodiment, the annular flange 410 has four third grooves 411, but is not limited thereto.

[0075] As an example, the first groove 510 and the third groove 411 are respectively misaligned in their orthographic projections on the plane containing the first surface 101. In other words, the first groove 510 and the third groove 411 are misaligned along the axial direction of the pole post 200.

[0076] In the embodiments of this application, the first groove 510 and the third groove 411 are designed to be staggered along the axial direction of the pole post 200, which can improve the uniformity of the pole post pressing force distribution, thereby avoiding the area where the groove is located from overlapping along the axial direction of the pole post to form a weak area that is prone to leakage points, thus improving the overall sealing performance of the end cap assembly.

[0077] Furthermore, the first groove 510, the second groove 321, and the third groove 411 are respectively staggered on the plane of the first surface 101, which further improves the uniformity of the distribution of the pole post pressing force, thereby avoiding the formation of weak areas by overlapping along the axial direction of the pole post in the area where the grooves are located, which can easily lead to leakage points, and improving the overall sealing performance of the end cap assembly.

[0078] As shown in Figures 5 and 11, the seal 600 is located within the recessed groove 104 and is fitted around the outer periphery of the first annular portion 310. The seal 600 includes a sealing ring 610 and a plurality of protrusions 620. The sealing ring 610 is located between the end plate 100 and the connector 500, and the plurality of protrusions 620 protrude from the inner annular surface of the sealing ring 610 and are arranged circumferentially along the sealing ring 610.

[0079] On the one hand, the multiple protrusions 620 can make the sealing ring 610 form an irregularly shaped annular structure, preventing the sealing ring 610 from converging towards the center of the sealing ring 610 after being pressed by the connector 500. This avoids the sealing ring 610 blocking the connection between the connector 500 and the second column segment 220 and forming a temporary seal. Therefore, when there is a welding defect at the welding position between the connector 500 and the second column segment 220, the end cap assembly 30 cannot pass the airtightness test, thus improving the accuracy of the airtightness test. On the other hand, when the sealing element 600 is fitted into the outer periphery of the pole post 200, the multiple protrusions 620 can play a guiding role, which is beneficial to improving the assembly efficiency.

[0080] As shown in Figure 12, in one embodiment, the orthographic projection of the sealing ring 610 on the plane where the first surface 101 is located is the fifth projection S5; wherein, the first projection S1 and the fifth projection S5 do not coincide.

[0081] Alternatively, as shown in Figure 13, in another embodiment, the first projection S1 and the fifth projection S5 have a sixth projection S6 that overlaps, and the maximum radial dimension of the sixth projection S6 along the fifth projection S5 is less than half the annular width of the fifth projection S5. Here, the annular width refers to the outer radius minus the inner radius of the fifth projection S5.

[0082] In this embodiment, the sealing ring 610 forms an annular sealing surface after contacting the connector 500. Since the first projection S1 and the fifth projection S5 do not coincide or the maximum size of the sixth projection S6 is less than half the annular width of the fifth projection S5, the first groove 510 does not completely penetrate the sealing surface. This ensures that the sealing ring 610, the end plate 100, and the connector 500 can all form a flat annular sealing surface. After the sealing ring 610 is squeezed, the sealing surface is subjected to uniform force, resulting in higher sealing performance.

[0083] As shown in Figure 14, this embodiment of the application also provides an electrical device 4, which can be an energy storage device, a vehicle, an energy storage container, etc. The electrical device 4 includes the energy storage device 1 described in the above embodiment, and the energy storage device 1 supplies power to the electrical device 4. Thus, for an electrical device 4 including the aforementioned energy storage device 1, the stability of the electrical device 4's operation can be improved, the probability of the electrical device 4 failing can be reduced, and the safety of using the electrical device 4 can be improved.

[0084] It is understood that the various embodiments / implementations provided in this application can be combined with each other without creating contradictions, and will not be described one by one here.

[0085] In the embodiments of this application, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; the term "multiple" refers to two or more unless otherwise expressly defined. The terms "install," "connect," "link," and "fix" should be interpreted broadly. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "link" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0086] In the description of the embodiments of the application, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the application and simplifying the description, and do not indicate or imply that the device or unit referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the application.

[0087] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the claims. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0088] The above are merely preferred embodiments of the application examples and are not intended to limit the application examples. For those skilled in the art, the application examples can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the application examples should be included within the protection scope of the application examples.

Claims

1. An end cap assembly for an energy storage device, comprising: An end plate having a first surface and a second surface disposed opposite to each other along its thickness direction; The end plate also has a first pole hole, which penetrates the first surface and the second surface; An electrode post has a first segment and a second segment along its axial direction. The cross-sectional area of ​​the first segment is larger than that of the second segment. The outer peripheral surfaces of the first and second segments are connected by an annular stepped surface. The first segment passes through a hole in the first electrode post. A connector is located on the side of the annular stepped surface of the pole post, and has a second pole post hole coaxially arranged with the first pole post hole. The second pole segment passes through the second pole post hole and is connected to the connector. The connector has at least one first groove on the side facing the annular stepped surface, and the first groove communicates with the second pole post hole. Wherein, the orthographic projection of the first groove on the plane where the first surface is located is the first projection (S1), and the orthographic projection of the annular step surface on the plane where the first surface is located is the second projection (S2). The first projection (S1) and the second projection (S2) have an overlapping area, and a portion of the first projection (S1) extends beyond the outer contour line of the second projection (S2).

2. The end cap assembly according to claim 1, wherein, The side surface of the connector facing the annular step surface is press-fitted with the annular step surface.

3. The end cap assembly according to claim 1, wherein, The connector has a plurality of first grooves, each first groove extending radially along the second pole hole, and the plurality of first grooves are arranged at equal intervals along the circumference of the second pole hole.

4. The end cap assembly according to claim 1, wherein, The end cap assembly also includes an upper insulating member, comprising a first annular portion, a second annular portion, and a third annular portion connected together. The first annular portion passes through the first pole post hole and surrounds the outer periphery of the first post segment. The second annular portion and the third annular portion are located on the side of the first surface of the end plate. The pole post also has a third column segment, the first column segment is connected between the second column segment and the third column segment, the cross-sectional area of ​​the third column segment is larger than the cross-sectional area of ​​the first column segment, the third annular portion surrounds the outer periphery of the third column segment, and the second annular portion is disposed between the third column segment and the end plate; The second annular portion has at least one second groove on the side facing the third column segment, the second groove extending from the inner annular surface of the first annular portion to the inner annular surface of the third annular portion.

5. The end cap assembly according to claim 4, wherein, The second annular portion has a plurality of second grooves, each second groove extending radially along the pole post, and the plurality of second grooves are arranged at equal intervals along the circumference of the pole post.

6. The end cap assembly according to claim 4, wherein, The first groove and the second groove are offset from each other on the plane where the first surface is located.

7. The end cap assembly according to claim 1, wherein, The end cap assembly further includes a lower insulating member located on the side of the second surface of the end plate, the lower insulating member having an annular flange located on the side of the connector facing the annular stepped surface; The annular flange has a third pole hole coaxially arranged with the first pole hole, and the first column segment passes through the third pole hole; The annular flange has at least one third groove on the side facing the connector, and the third groove communicates with the third pole hole; The orthographic projection of the third groove onto the plane of the first surface is the third projection (S3), and the orthographic projection of the connector onto the plane of the first surface is the fourth projection (S4). The third projection (S3) and the fourth projection (S4) have an overlapping area, and a portion of the third projection (S3) extends beyond the outer contour line of the fourth projection (S4).

8. The end cap assembly according to claim 7, wherein, The annular flange has a plurality of third grooves, each third groove extending radially along the third pole hole, and the plurality of third grooves are arranged at equal intervals along the circumference of the third pole hole.

9. The end cap assembly according to claim 7, wherein, The first groove and the third groove are offset from each other on the plane of the first surface.

10. The end cap assembly according to claim 7, wherein, The end plate also has a recessed groove, which is recessed from the second surface along the thickness direction of the end plate toward the first surface, and the first pole hole penetrates the bottom surface of the recessed groove; the annular flange is located inside the recessed groove. The lower insulating member further includes an insulating sheet and a fourth annular portion. The insulating sheet is located on the side of the second surface of the end plate and has a through hole. The through hole penetrates the insulating sheet along the thickness direction of the end plate, and the connector is confined within the through hole. The fourth annular portion is connected to the edge of the through hole and protrudes from the surface of the insulating sheet facing the end plate. The fourth annular portion is located in the recessed groove and surrounds the outer periphery of the connector. The annular flange protrudes from the inner annular surface of the fourth annular portion, and the third groove extends from the hole wall of the third pole post hole to the inner annular surface of the fourth annular portion.

11. The end cap assembly according to claim 1, wherein, The end cap assembly further includes a sealing element, which includes a sealing ring and a plurality of protrusions. The sealing ring is sleeved on the outer periphery of the pole post and located between the end plate and the connector. The plurality of protrusions protrude from the inner annular surface of the sealing ring and are arranged circumferentially along the sealing ring.

12. The end cap assembly according to claim 1, wherein, The end cap assembly also includes a sealing ring, which is sleeved on the outer periphery of the pole post and located between the end plate and the connector; the orthographic projection of the sealing ring on the plane of the first surface is the fifth projection (S5); Wherein, the first projection (S1) does not coincide with the fifth projection (S5); or, the first projection (S1) and the fifth projection (S5) have a sixth projection (S6) that coincides, and the maximum radial dimension of the sixth projection (S6) along the fifth projection (S5) is less than half the ring width of the fifth projection (S5).

13. An energy storage device, comprising: The housing includes a receiving cavity with an opening; The electrode assembly is housed within the receiving cavity; as well as The end cap assembly according to any one of claims 1 to 12, wherein the end cap assembly closes the opening of the receiving cavity.

14. An electrical appliance comprising the energy storage device of claim 13, wherein the energy storage device supplies power to the electrical appliance.

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