End cover assembly, energy storage device and electric equipment

Abstract

The utility model discloses an end cover assembly, an energy storage device and electric equipment. The end cover assembly comprises an end plate, a pole and a connecting piece. The end plate is provided with a first surface and a second surface which are oppositely arranged along the thickness direction; the end plate is also provided with a first pole hole penetrating through the end plate; the pole is provided with a first pole section and a second pole section, the peripheral surface of the first pole section is connected with the peripheral surface of the second pole section through an annular step surface, and the first pole section is arranged in the first pole hole in a penetrating manner; the connecting piece is located on the side where the annular step face of the pole is located and provided with a second pole hole coaxial with the first pole hole, and the second pole section is arranged in the second pole hole in a penetrating mode and connected with the connecting piece; one side, facing the annular step surface, of the connecting piece is provided with a first groove, and the first groove is communicated with the second pole hole; orthographic projections of the first groove and the annular step surface on a plane where the first surface is located have an overlapped area, and a part of a first projection of the first groove extends out of an outer contour line of a second projection of the annular step surface.

Description

Technical Field

[0001] The present application relates to the technical field of energy storage, and in particular, to an end cover assembly, an energy storage device including the end cover assembly, and an electrical equipment including the energy storage device. Background Art

[0002] In the related art, the end cover assembly of a battery needs to undergo airtightness detection during the manufacturing process to ensure the safety and service life of the battery during use. However, in the related art, the pole column assembly of the end cover assembly may temporarily meet the airtightness requirements (i.e., "false seal") due to the fitting connection of the abutting surfaces between relatively hard components and hard components during press-fitting assembly. It will pass the airtightness detection and be put into use as a qualified product. However, during the subsequent long-term use, due to the fluctuation of the environmental temperature, hard components such as a metal pole column and a plastic insulating part have different expansion and contraction rates due to different materials, and the abutting surface may have a shrinkage gap resulting in air leakage, posing a serious safety hazard. Summary of the Utility Model

[0003] The embodiments of the present application provide an end cover assembly, an energy storage device, and an electrical equipment that can improve the accuracy of airtightness detection to solve the problems existing in the related art.

[0004] The end cover assembly of the embodiments of the present application is used for an energy storage device and includes:

[0005] An end plate having a first surface and a second surface disposed opposite to each other along its thickness direction; the end plate further has a first pole column hole penetrating through the first surface and the second surface;

[0006] A pole column having a first column section and a second column section along its axial direction, the cross-sectional area of the first column section being larger than that of the second column section, the outer peripheral surface of the first column section being connected to the outer peripheral surface of the second column section through an annular step surface, and the first column section being disposed in the first pole column hole; and

[0007] A connecting member located on one side of the annular step surface of the pole column and having a second pole column hole coaxially disposed with the first pole column hole, the second column section being disposed in the second pole column hole and connected to the connecting member; at least one first groove is provided on the side of the connecting member facing the annular step surface, and the first groove communicates with the second pole column hole;

[0008] Wherein, the positive projection of the first groove on the plane where the first surface is located is a first projection, the positive projection of the annular step surface on the plane where the first surface is located is a second projection, there is an overlapping area between the first projection and the second projection, and a part of the first projection extends beyond the outer contour line of the second projection.

[0009] In the end cap assembly according to the embodiment of the present application, at least one first groove is provided on one side of the connecting member facing the annular step surface. If there is a welding defect at the welding position between the connecting member and the second column section, even if the connecting member is in contact with the annular step surface, the welding position can communicate with the outside through the first groove. At this time, the end cap assembly with a welding defect at the welding position cannot pass the airtightness test, thereby improving the accuracy of the airtightness test and eliminating potential safety hazards.

[0010] Optionally, the surface of the connecting member facing the annular step surface is press-fitted with an interference fit to the annular step surface.

[0011] In the embodiment of the present application, since the connecting member has a first groove, the surface of the connecting member facing the annular step surface can be press-fitted with an interference fit to the annular step surface, so that the connecting member is tightly press-fitted to the annular step surface of the pole column. When laser welding is used between the connecting member and the pole column, the welding laser is not easily transmitted through the connection between the connecting member and the annular step surface to burn the upper insulating part and the sealing part, further improving the sealing performance of the sealing part.

[0012] Optionally, the connecting member has a plurality of the first grooves, each of the first grooves extends radially along the second pole column hole, and the plurality of the first grooves are arranged at equal intervals in the circumferential direction of the second pole column hole.

[0013] Optionally, the end cap assembly further includes an upper insulating part, which includes a connected first annular part, a second annular part and a third annular part. The first annular part is disposed in the first pole column hole and surrounds the outer periphery of the first column section. The second annular part and the third annular part are located on the side where the first surface of the end plate is located.

[0014] The pole column further has a third column section. The first column section is connected between the second column section and the third column section. The cross-sectional area of the third column section is larger than the cross-sectional area of the first column section. The third annular part surrounds the outer periphery of the third column section, and the second annular part is disposed between the third column section and the end plate.

[0015] At least one second groove is provided on the side of the second annular part facing the third column section. The second groove extends from the inner ring surface of the first annular part to the inner ring surface of the third annular part.

[0016] In the embodiment of the present application, since at least one second groove is provided on the side of the second annular part facing the third column section, when the sealing part is missing or damaged, the spaces on both sides in the thickness direction of the end cap assembly communicate through the second groove. At this time, the end cap assembly will not pass the airtightness test, thereby further improving the accuracy of the airtightness test of the end cap assembly.

[0017] Optionally, the second annular portion has a plurality of the second grooves, each of the second grooves extending along the radial direction of the pole column, and the plurality of the second grooves are arranged at equal intervals in the circumferential direction of the pole column.

[0018] Optionally, the positive projections of the first groove and the second groove on the plane where the first surface is located are arranged in a staggered manner.

[0019] In the embodiment of the present application, by designing the first groove and the second groove to be arranged in a staggered manner along the axial direction of the pole column, the uniformity of the pole column pressing force distribution can be improved, thereby avoiding the formation of a weak area due to the overlap of the areas where the grooves are located along the axial direction of the pole column and easily forming leakage points, and improving the overall sealing performance of the end cover assembly.

[0020] Optionally, the end cover assembly further includes a lower insulating member located on the side where the second surface of the end plate is located. The lower insulating member has an annular flange, and the annular flange is located on the side of the connecting member facing the annular step surface;

[0021] The annular flange has a third pole column hole coaxially arranged with the first pole column hole, and the first column section passes through the third pole column hole;

[0022] The side of the annular flange facing the connecting member has at least one third groove, and the third groove communicates with the third pole column hole;

[0023] The positive projection of the third groove on the plane where the first surface is located is a third projection, the positive projection of the connecting member on the plane where the first surface is located is a fourth projection, there is an overlapping area between the third projection and the fourth projection, and a part of the third projection extends beyond the outer contour line of the fourth projection.

[0024] In the embodiment of the present application, since the side of the annular flange facing the connecting member has a third groove, in the case of missing installation of the sealing member or damage of the sealing member, the spaces on both sides in the thickness direction of the end cover assembly communicate through the third groove. At this time, the end cover assembly will not pass the airtightness detection, thereby further improving the accuracy of the airtightness detection of the end cover assembly.

[0025] Optionally, the annular flange has a plurality of the third grooves, each of the third grooves extending along the radial direction of the third pole column hole, and the plurality of the third grooves are arranged at equal intervals in the circumferential direction of the third pole column hole.

[0026] Optionally, the positive projections of the first groove and the third groove on the plane where the first surface is located are arranged in a staggered manner.

[0027] In the embodiment of the present application, the first groove and the third groove are designed to be arranged in a staggered manner along the axial direction of the pole column, which can improve the uniformity of the pole column pressing force distribution, and further avoid the formation of a weak area due to the overlap of the areas where the grooves are located along the axial direction of the pole column, thereby easily forming leakage points, and improving the overall sealing performance of the end cover assembly.

[0028] Optionally, the end plate further has a sunken groove, the sunken groove is recessed from the second surface along the thickness direction of the end plate towards the first surface, and the first pole column hole penetrates through the bottom surface of the sunken groove; the flange is located in the sunken groove;

[0029] The lower insulating member further includes an insulating sheet and a fourth annular portion. The insulating sheet is located on the side where the second surface of the end plate is located, and has a through hole. The through hole penetrates through the insulating sheet along the thickness direction of the end plate, and the connecting member is limited in the through hole;

[0030] The fourth annular portion is connected to the edge of the through hole, and protrudes from the side surface of the insulating sheet facing the end plate. The fourth annular portion is located in the sunken groove and surrounds the outer periphery of the connecting member;

[0031] The flange protrudes from the inner ring surface of the fourth annular portion, and the third groove extends from the hole wall of the third pole column hole to the inner ring surface of the fourth annular portion.

[0032] Optionally, the end cover assembly further includes a seal, the seal includes a sealing ring and a plurality of protrusions. The sealing ring is sleeved on the outer periphery of the pole column and is located between the end plate and the connecting member. The plurality of protrusions protrude from the inner ring surface of the sealing ring and are arranged along the circumferential direction of the sealing ring.

[0033] On the one hand, the plurality of protrusions can make the sealing ring form an irregularly shaped ring structure, prevent the sealing ring from gathering towards the center of the sealing ring after being pressed by the connecting member, and further avoid the sealing ring from sealing the connection between the connecting member and the second column section to form a temporary seal. Thus, when there are welding defects at the welding position between the connecting member and the second column section, the end cover assembly cannot pass the airtightness test, improving the accuracy of the airtightness test; on the other hand, when the seal is sleeved on the outer periphery of the pole column, the plurality of protrusions can play a guiding role, which is beneficial to improving the assembly efficiency.

[0034] Optionally, the end cover assembly further includes a sealing ring. The sealing ring is sleeved on the outer periphery of the pole column and is located between the end plate and the connecting member; the orthographic projection of the sealing ring on the plane where the first surface is located is the fifth projection.

[0035] Wherein, the first projection does not coincide with the fifth projection; or, there is a coincident sixth projection between the first projection and the fifth projection, and the maximum dimension of the sixth projection along the radial direction of the fifth projection is less than half of the annular width of the fifth projection.

[0036] In the embodiment of the present application, an annular sealing surface is formed after the sealing ring contacts the connecting piece. Since the first projection does not coincide with the fifth projection or the maximum dimension of the sixth projection is less than half of the annular width of the fifth projection, the first groove does not completely penetrate the sealing surface, thereby ensuring that flat annular sealing surfaces can be formed between the sealing ring and the end plate and the connecting piece. After the sealing ring is squeezed, the sealing surface is evenly stressed and the sealing performance is higher.

[0037] The energy storage device of the embodiment of the present application includes:

[0038] A housing including a receiving cavity with an opening;

[0039] An electrode assembly accommodated in the receiving cavity; and

[0040] The end cover assembly according to any one of the above, the end cover assembly closing the opening of the receiving cavity.

[0041] The electrical device of the embodiment of the present application includes the above energy storage device, and the energy storage device supplies power to the electrical device. Description of the Drawings

[0042] Figure 1 Shows a schematic structural diagram of a household energy storage system.

[0043] Figure 2 Shows an exploded schematic view of a single battery of the embodiment of the present application.

[0044] Figure 3 Shows an exploded schematic view of the end cover assembly of the embodiment of the present application.

[0045] Figure 4 Shows a top view of the end cover assembly of the embodiment of the present application.

[0046] Figure 5 Shows along Figure 4 A partial cross-sectional view taken along the A-A cutting line in

[0047] Figure 6 Shows a schematic view of the connecting piece of the embodiment of the present application.

[0048] Figure 7 Shows a schematic diagram of the positional relationship between the first projection and the second projection.

[0049] Figure 8 Shows a schematic view of the upper insulating member of the embodiment of the present application.

[0050] Figure 9 Shown is a schematic diagram of the lower insulating part of an embodiment of the present application.

[0051] Figure 10 Shown is a schematic diagram of the positional relationship between the third projection and the fourth projection.

[0052] Figure 11 Shown is a schematic diagram of the seal of an embodiment of the present application.

[0053] Figure 12 Shown is a schematic diagram of the positional relationship between the first projection and the fifth projection.

[0054] Figure 13 Shown is another schematic diagram of the positional relationship between the first projection and the fifth projection.

[0055] Figure 14 Shown is a schematic diagram of the electrical equipment of an embodiment of the present application.

[0056] Among them, the reference numerals are explained as follows:

[0057] 1. Energy storage device; 2. Electric energy conversion device; 3. User load; 4. Electrical equipment;

[0058] 10. Housing; 11. Accommodating cavity; 12. Opening; 20. Electrode assembly; 30. End cover assembly;

[0059] 100. End plate; 101. First surface; 102. Second surface; 103. First pole post hole; 104. Sinking groove; 105. Vent hole; 106. Liquid injection hole;

[0060] 200. Pole post; 210. First column section; 220. Second column section; 230. Third column section; 240. Annular step surface;

[0061] 300. Upper insulating part; 310. First annular part; 320. Second annular part; 321. Second groove; 330. Third annular part;

[0062] 400. Lower insulating part; 401. Third pole post hole; 410. Annular flange; 411. Third groove; 420. Insulating sheet; 421. Through hole; 430. Fourth annular part;

[0063] 500. Connecting piece; 501. Second pole post hole; 510. First groove;

[0064] 600. Seal; 610. Sealing ring; 620. Protrusion;

[0065] 700. Explosion-proof valve;

[0066] 800. Protection piece. Detailed Implementation Modes

[0067] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. Like reference numerals in the figures denote like or similar structures, and thus their detailed description will be omitted.

[0068] It can be 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 listed steps or units, but may optionally further include steps or units not listed, or may optionally further include other steps or components inherent to these processes, methods, products, or devices.

[0069] Since the energy required by people has strong temporality and spatiality, in order to rationally utilize energy and improve the energy utilization rate, it is necessary to store one form of energy in the same or converted into another form of energy through a medium or device, and then release it in a specific energy form based on future application needs.

[0070] Current energy storage (i.e., energy storage) application scenarios are relatively wide, including power generation side energy storage, grid side energy storage, renewable energy grid connection energy storage, and user side energy storage, etc. The types of corresponding energy storage devices include:

[0071] (1) Large energy storage containers applied in the grid side energy storage scenario, which can be used as high-quality active and reactive power regulation power sources in the grid, realize load matching of electric energy in time and space, enhance the consumption capacity of renewable energy, and are of great significance in grid system standby, alleviating the power supply pressure during peak loads, and peak shaving and frequency modulation;

[0072] (2) Small and medium-sized energy storage cabinets applied in the industrial and commercial energy storage scenarios (such as banks, shopping malls, etc.) on the user side and household small energy storage boxes applied in the household energy storage scenarios on the user side. The main operation mode is "peak shaving and valley filling". Since there is a large price difference in electricity charges at the peak and valley positions according to the electricity consumption demand, after users have energy storage devices, in order to reduce costs, they usually charge the energy storage cabinet / box during the low electricity price period; during the peak electricity price period, the electricity in the energy storage device is released for use to achieve the purpose of saving electricity charges. In addition, in remote areas and areas with high incidences of natural disasters such as earthquakes and hurricanes, the existence of household energy storage devices is equivalent to users providing backup power for themselves and the grid, eliminating the inconvenience caused by frequent power outages due to disasters or other reasons.

[0073] Taking the household energy storage scenario in user-side energy storage as an example for illustration, Figure 1 There is shown a household energy storage system, which includes an energy storage device 1 and an electric energy conversion device 2 (such as a photovoltaic panel), as well as a user load 3 (such as street lights, household appliances, etc.). The energy storage device 1 is a small energy storage box that can be installed on an outdoor wall in a wall-mounted manner. Specifically, the electric energy conversion device 2 can convert solar energy into electric energy during the low electricity price period and store it through the energy storage device 1, and then supply it to the user load 3 for use during the high electricity price period, or supply it to the user load 3 for use when the power grid is powered off / out of power.

[0074] Combined with the above situation of storing energy by physical or electrochemical means, taking electrochemical energy storage as an example, the energy storage device 1 includes at least one group of chemical batteries, using the chemical elements in the chemical batteries as the energy storage medium to achieve the charge and discharge process through the chemical reaction or change of the energy storage medium. Simply put, the electric energy generated by light energy and wind energy is stored in at least one group of chemical batteries through the chemical reaction or change of the energy storage medium, and then the electric quantity stored in at least one group of chemical batteries is released for use through the chemical reaction or change of the energy storage medium when the use of external electric energy reaches the peak, or transferred to places with a shortage of electric quantity for reuse.

[0075] The embodiment of the present 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, a battery system, etc. composed of single batteries. For a single battery, it can be a lithium-ion battery, a sodium-ion battery, a sodium-lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium-sulfur battery, a magnesium-ion battery, a nickel-metal hydride battery, a nickel-cadmium battery, a lead-acid battery, etc. The single battery can be in a cylindrical shape, a flat shape, a cuboid shape, etc., and the embodiment of the present application does not limit this. Next, taking the energy storage device 1 as a cuboid single battery as an example, the energy storage device 1 will be explained in detail.

[0076] As Figure 2 shown, the energy storage device 1 of the embodiment of the present application includes a housing 10, an electrode assembly 20, and an end cap assembly 30. The housing 10 includes a receiving cavity 11 having an opening 12, the electrode assembly 20 is received 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.

[0077] Among them, the housing 10 can be a cylindrical structure with an opening 12 at one end. At this time, the energy storage device 1 includes an end cap assembly 30, and the end cap assembly 30 seals the opening 12. Of course, the housing 10 can also be a cylindrical structure with openings 12 at both ends. At this time, the energy storage device 1 can include an end cap assembly 30 and a cover plate, or the energy storage device 1 includes two end cap assemblies 30. In this way, an 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.

[0078] Optionally, the housing 10 can be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite shell), or an aluminum plastic film, etc.

[0079] Among them, the electrode assembly 20 includes a positive electrode plate, a negative electrode plate, and a separator. The single cell mainly works by the movement of metal ions between the positive electrode plate and the negative electrode plate. The positive electrode plate includes a positive electrode current collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode current collector. The positive electrode current collector without the coated positive electrode active material layer protrudes from the positive electrode current collector with the coated positive electrode active material layer. The positive electrode current collector without the coated positive electrode active material layer serves as the positive electrode tab. Taking a lithium-ion battery as an example, the material of the positive electrode current collector can be aluminum, and the positive electrode active material can be lithium cobaltate, lithium iron phosphate, ternary lithium, or lithium manganate, etc. The negative electrode plate includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the negative electrode current collector. The negative electrode current collector without the coated negative electrode active material layer protrudes from the negative electrode current collector with the coated negative electrode active material layer. The negative electrode current collector without the coated negative electrode active material layer serves as the negative electrode tab. The material of the negative electrode current collector can be copper, and the negative electrode 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 the present application are not limited thereto.

[0080] The positive electrode tab and the negative electrode tab can be located at the same end of the electrode assembly 20 (such as a square single cell), or can be located at different ends of the electrode assembly 20 (such as a cylindrical single cell). When the positive electrode tab and the negative electrode tab are located at the same end of the electrode assembly 20, the end cap assembly 30 can be provided with a positive electrode post and a negative electrode post, and the positive electrode post is connected to the positive electrode tab, and the negative electrode post is connected to the negative electrode tab to realize the output of the electrical energy of the electrode assembly 20 through the positive electrode post and the negative electrode post. When the positive electrode tab and the negative electrode tab are respectively located at both ends of the electrode assembly 20, one of the positive electrode tab and the negative electrode tab is connected to the electrode post provided by the end cap assembly 30, and the other of the positive electrode tab and the negative electrode tab is connected to the bottom of the housing 10 or the electrode post provided by the other end cap assembly 30. The electrode post connected to the positive electrode tab serves as the positive electrode post, and the electrode post connected to the negative electrode tab serves as the negative electrode post.

[0081] Such as Figure 3As shown, the end cover assembly 30 includes an end plate 100, an explosion-proof valve 700, and a protective sheet 800. The end plate 100 is connected to the housing 10 and seals the opening 12 of the accommodation cavity 11. The connection method between the end plate 100 and the housing 10 can be welding, but is not limited thereto. The shape of the end plate 100 is adapted to the shape of the opening 12. In the embodiment of the present application, the shape of the opening 12 is rectangular, so the shape of the end plate 100 is also rectangular.

[0082] The end plate 100 has a vent hole 105, and the vent hole 105 penetrates the end plate 100 along the thickness direction of the end plate 100. The explosion-proof valve 700 is connected to one side surface of the end plate 100 facing the electrode assembly 20 and closes the vent hole 105. The explosion-proof valve 700 is used to burst and discharge the gas generated in the accommodation cavity 11 of the housing 10 when the air pressure of the energy storage device 1 reaches a certain pressure threshold, so as to avoid the battery swelling to explosion, thereby improving the safety of the energy storage device 1.

[0083] Among them, the protective sheet 800 is attached to the side of the end plate 100 facing away from the electrode assembly 20, seals the vent hole 105, and covers the explosion-proof valve 700, playing a role in protecting the explosion-proof valve 700.

[0084] The end plate 100 is also provided with a liquid injection hole 106, and the liquid injection hole 106 penetrates the end plate 100 along the thickness direction of the end plate 100. After the end cover assembly 30 seals the opening 12 of the accommodation cavity 11, the electrolyte can be injected into the accommodation cavity 11 of the housing 10 through the liquid injection hole 106. After the injection of the electrolyte is completed, a seal (not shown in the figure) can be used to seal the liquid injection hole 106 to avoid the leakage of the electrolyte.

[0085] As Figures 3 to 5 shown, the end cover assembly 30 further includes a terminal post 200, an upper insulating member 300, a lower insulating member 400, a connecting member 500, and a sealing member 600. The end plate 100 has a first surface 101 and a second surface 102 arranged opposite to each other along its thickness direction. The end plate 100 also has a first terminal post hole 103, and the first terminal post hole 103 penetrates the first surface 101 and the second surface 102. The terminal post 200 is limited in the first terminal post hole 103. The upper insulating member 300, the lower insulating member 400, the connecting member 500, and the sealing member 600 are all installed on the end plate 100. In one embodiment, the end plate 100 is a light aluminum sheet, but is not limited thereto. The upper insulating member 300 and the lower insulating member 400 are made of insulating materials, such as plastics.

[0086] The lower insulating part 400 and the end plate 100 are stacked on the second surface 102 of the end plate 100, and are used for insulating the pole column 200 from the end plate 100. The upper insulating part 300 surrounds the outer periphery of the pole column and is used for insulating the pole column 200 from the end plate 100. The connecting part 500 is connected to one end of the pole column 200 extending out of the second surface 102, for example, by welding. The sealing part 600 is sealed between the end plate 100 and the connecting part 500.

[0087] As Figure 5 and Figure 6 shown, the pole column 200 has a first column section 210 and a second column section 220 along its axial direction. The first column section 210 and the second column section 220 are coaxially arranged, and the cross-sectional area of the first column section 210 is larger than that of the second column section 220. The outer peripheral surface of the first column section 210 is connected to the outer peripheral surface of the second column section 220 through an annular step surface 240. The first column section 210 is disposed through the first pole column hole 103. The connecting part 500 is located on the side where the annular step surface 240 of the pole column is located, and has a second pole column hole 501 coaxially arranged with the first pole column hole 103. The second column section 220 is disposed through the second pole column hole 501 and is connected to the connecting part 500. At least one first groove 510 is provided on one side of the connecting part 500 facing the annular step surface 240, and the first groove 510 communicates with the second pole column hole 501.

[0088] As Figure 7 shown, the positive projection of the first groove 510 on the plane where the first surface 101 is located is the first projection S1, and the positive projection of the annular step surface 240 on the plane where the first surface 101 is located is the second projection S2. There is an overlapping area between the first projection S1 and the second projection S2, and a part of the first projection S1 extends out of the outer contour line of the second projection S2.

[0089] It should be noted that the connecting part 500 and the second column section 220 of the pole column are generally connected by welding, and the quality of the welding position between the connecting part 500 and the second column section 220 determines the sealing performance between the connecting part 500 and the second column section 220. If there are welding defects at the welding position, such as welding pinholes, welding holes, etc., the end cover assembly 30 cannot pass the airtightness test. However, after the connecting part 500 and the second column section 220 are welded, the connecting part 500 may press against the annular step surface 240. At this time, a seal is formed between the annular step surface 240 and one side surface of the connecting part 500. Even if there are welding defects at the welding position, the end cover assembly 30 will still pass the airtightness test.

[0090] In the end cap assembly 30 according to the embodiment of the present application, at least one first groove 510 is provided on one side of the connecting member 500 facing the annular stepped surface 240. If there is a welding defect at the welding position between the connecting member 500 and the second column section 220, even if the connecting member 500 is in contact with the annular stepped surface 240, the welding position can communicate with the outside through the first groove 510. At this time, the end cap assembly 30 with a welding defect at the welding position cannot pass the airtightness test, thereby improving the accuracy of the airtightness test and eliminating potential safety hazards.

[0091] In one embodiment, the surface of the connecting member 500 on the side facing the annular stepped surface 240 is press-fitted with an interference fit to the annular stepped surface 240.

[0092] In the embodiment of the present application, since the connecting member 500 has the first groove 510, the surface of the connecting member 500 on the side facing the annular stepped surface 240 can be press-fitted with an interference fit to the annular stepped surface 240, so that the connecting member 500 is tightly press-fitted to the annular stepped surface 240 of the pole column 200. When laser welding is used between the connecting member 500 and the pole column 200, the welding laser is not easily transmitted through the connection between the connecting member 500 and the annular stepped surface 240 to burn the upper insulating member 300 and the sealing member 600, further improving the sealing performance of the sealing member 600.

[0093] As Figure 6 shown, the connecting member 500 has a plurality of first grooves 510. Each first groove 510 penetrates the hole wall of the second pole column hole 501 and extends in the radial direction of the second pole column hole 501. The plurality of first grooves 510 are arranged at equal intervals in the circumferential direction of the second pole column hole 501.

[0094] In one embodiment, the connecting member 500 has four first grooves 510, but is not limited thereto.

[0095] As Figure 5 and Figure 8 shown, the upper insulating member 300 includes a connected first annular portion 310, a second annular portion 320, and a third annular portion 330. The first annular portion 310 is disposed in the first pole column hole 103 and surrounds the outer circumference of the first column section 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.

[0096] The pole column 200 further has a third column section 230, and the third column section 230 is coaxially arranged with the first column section 210. The first column section 210 is connected between the second column section 220 and the third column section 230. The cross-sectional area of the third column section 230 is larger than the cross-sectional area of the first column section 210. The third annular portion 330 surrounds the outer circumference of the third column section 230, and the second annular portion 320 is disposed between the third column section 230 and the end plate 100.

[0097] One side of the second annular portion 320 facing the third column section 230 has at least one second groove 321, and the second groove 321 extends from the inner ring surface of the first annular portion 310 to the inner ring surface of the third annular portion 330.

[0098] In an embodiment of the present application, since one side of the second annular portion 320 facing the third column section 230 has the second groove 321, when the seal 600 is missing or damaged, the spaces on both sides of the end cap assembly 30 in the thickness direction communicate with each other through the second groove 321. At this time, 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.

[0099] In one embodiment, the second annular portion 320 has a plurality of second grooves 321, each second groove 321 extends along the radial direction of the pole column 200, and the plurality of second grooves 321 are arranged at equal intervals along the circumferential direction of the pole column.

[0100] As an example, the orthographic projections of the first groove 510 and the second groove 321 on the plane where the first surface 101 is located are arranged in a staggered manner. In other words, the first groove 510 and the second groove 321 are arranged in a staggered manner along the axial direction of the pole column 200.

[0101] In an embodiment of the present application, the first groove 510 and the second groove 321 are designed to be arranged in a staggered manner along the axial direction of the pole column 200, which can improve the uniformity of the pressing force distribution of the pole column 200, and further avoid the formation of a weak area due to the overlap of the areas where the grooves are located along the axial direction of the pole column, thus easily forming leakage points, and improving the overall sealing performance of the end cap assembly.

[0102] As Figure 5 and Figure 9 shown, the end plate 100 further has a sunken groove 104, the sunken groove 104 is recessed from the second surface 102 along the thickness direction of the end plate 100 towards the first surface 101, and the first pole column hole 103 penetrates through the bottom surface of the sunken groove 104.

[0103] 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 where the second surface 102 of the end plate 100 is located, and has a through hole 421, the through hole 421 penetrates through the insulating sheet 420 along the thickness direction of the end plate 100, the second column section 220 is inserted into the through hole 421, and the connecting member 500 is limited in the through hole 421.

[0104] 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 sunken groove 104 and surrounds the outer periphery of the connecting member 500.

[0105] The annular flange 410 protrudes from the inner ring surface of the fourth annular portion 430, is located on the side of the connecting member 500 facing the annular step surface 240, and is located in the sinking groove 104. The annular flange 410 has a third pole hole 401 coaxially arranged with the first pole hole 103, and the first column section 210 is inserted into the third pole hole 401. The side of the annular flange 410 facing the connecting member 500 has at least one third groove 411, and the third groove 411 communicates with the third pole hole 401. The third groove 411 extends from the hole wall of the third pole hole 401 to the inner ring surface of the fourth annular portion 430.

[0106] As Figure 10 shown, the positive projection of the third groove 411 on the plane where the first surface 101 is located is the third projection S3, and the positive projection of the connecting member 500 on the plane where the first surface 101 is located is the fourth projection S4. There is an overlapping area between the third projection S3 and the fourth projection S4, and a part of the third projection S3 extends beyond the outer contour line of the fourth projection S4.

[0107] In the embodiment of the present application, since the side of the annular flange 410 facing the connecting member 500 has the third groove 411, when the seal 600 is missing or damaged, the spaces on both sides in the thickness direction of the end cap assembly 30 communicate through the third groove 411. At this time, 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.

[0108] As Figure 9 shown, the annular flange 410 has a plurality of third grooves 411. Each third groove 411 penetrates the hole wall of the third pole hole 401 and extends along the radial direction of the third pole hole 401. The plurality of third grooves 411 are arranged at equal intervals in the circumferential direction of the third pole hole 401.

[0109] In one embodiment, the annular flange 410 has four third grooves 411, but it is not limited thereto.

[0110] As an example, the positive projections of the first groove 510 and the third groove 411 on the plane where the first surface 101 is located are arranged in a staggered manner. In other words, the first groove 510 and the third groove 411 are arranged in a staggered manner along the axial direction of the pole 200.

[0111] In the embodiment of the present application, the first groove 510 and the third groove 411 are designed to be arranged in a staggered manner along the axial direction of the pole 200, which can improve the uniformity of the pole pressing force distribution, and further avoid the formation of a weak area due to the overlap of the areas where the grooves are located along the axial direction of the pole, thereby easily forming a leakage point, and improving the overall sealing performance of the end cap assembly.

[0112] Further, the orthographic projections of the first groove 510, the second groove 321, and the third groove 411 on the plane where the first surface 101 is located are arranged in a staggered manner, further improving the uniformity of the pole column pressing force distribution, thereby avoiding the formation of a weak area due to the overlap of the areas where the grooves are located along the axial direction of the pole column and easily forming leakage points, and improving the overall sealing performance of the end cover assembly.

[0113] As Figure 5 and Figure 11 shown, the seal 600 is located in the sinking groove 104 and sleeved on 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 connecting member 500. The plurality of protrusions 620 protrude from the inner ring surface of the sealing ring 610 and are arranged along the circumferential direction of the sealing ring 610.

[0114] On the one hand, the plurality of protrusions 620 can make the sealing ring 610 form an irregularly shaped annular structure, preventing the sealing ring 610 from gathering towards the center of the sealing ring 610 after being pressed by the connecting member 500, thereby avoiding the sealing ring 610 from sealing the connection between the connecting member 500 and the second column section 220 to form a temporary seal. Thus, when there are welding defects at the welding position between the connecting member 500 and the second column section 220, the end cover assembly 30 cannot pass the airtightness test, improving the accuracy of the airtightness test; on the other hand, when the seal 600 is sleeved on the outer periphery of the pole column 200, the plurality of protrusions 620 can play a guiding role, which is beneficial to improving the assembly efficiency.

[0115] As Figure 12 shown, in an 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 does not coincide with the fifth projection S5.

[0116] Or, as Figure 13 shown, in another embodiment, there is a sixth projection S6 where the first projection S1 coincides with the fifth projection S5, and the maximum dimension of the sixth projection S6 along the radial direction of the fifth projection S5 is less than half of the ring width of the fifth projection S5. Wherein, the ring width refers to the outer circle radius - inner circle radius of the fifth projection S5.

[0117] In the embodiment of the present application, an annular sealing surface is formed after the sealing ring 610 contacts the connecting member 500. Since the first projection S1 does not coincide with the fifth projection S5 or the maximum dimension of the sixth projection S6 is less than half of the ring width of the fifth projection S5, the first groove 510 does not completely penetrate the sealing surface, thereby ensuring that the sealing ring 610 can form a flat annular sealing surface with both the end plate 100 and the connecting member 500. The sealing surface of the sealing ring 610 is uniformly stressed after being squeezed, and the sealing performance is higher.

[0118] As Figure 14As shown in the figure, an embodiment of the present application also provides an electrical device 4, which may 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. In this way, for the electrical device 4 including the energy storage device 1 described above, the working stability of the electrical device 4 can be improved, the probability of the electrical device 4 crashing can be reduced, and the safety of using the electrical device 4 can be improved at the same time.

[0119] It can be understood that the various embodiments / implementation manners provided in the present application can be combined with each other without contradiction, and no further examples will be given here.

[0120] In the embodiments of the application, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance; the term "plurality" refers to two or more, unless otherwise clearly defined. Terms such as "installed", "connected", "connected", and "fixed" should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the application can be understood according to specific circumstances.

[0121] In the description of the embodiments of the application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the embodiments of the application and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the embodiments of the application.

[0122] In the description of this specification, the description of terms such as "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of the application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0123] The above are only the preferred embodiments of the embodiments of the application and are not used to limit the embodiments of the application. For those skilled in the art, the embodiments of the application can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the embodiments of the application shall be included in the protection scope of the embodiments of the application.

Claims

1. A end cap assembly for an energy storage device, characterized in that, Comprising: An end plate having a first surface and a second surface disposed opposite to each other in the thickness direction thereof; the end plate further has a first pole hole which penetrates through the first surface and the second surface; A pole, having a first column section and a second column section along its axial direction, the cross-sectional area of the first column section being larger than that of the second column section, the outer peripheral surface of the first column section being connected to the outer peripheral surface of the second column section through an annular step surface, and the first column section being inserted into the first pole hole; and A connecting member located on the side where the annular step surface of the pole is located, and having a second pole hole coaxially arranged with the first pole hole, the second column section being inserted into the second pole hole and connected to the connecting member; at least one first groove is provided on the side of the connecting member facing the annular step surface, and the first groove communicates with the second pole hole; Wherein, the positive projection of the first groove on the plane where the first surface is located is a first projection (S1), the positive projection of the annular step surface on the plane where the first surface is located is a second projection (S2), there is an overlapping area between the first projection (S1) and the second projection (S2), and a part 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, characterized in that, The side surface of the connecting member facing the annular step surface is press-fitted with the annular step surface with an interference fit.

3. The end cap assembly according to claim 1, wherein The end cover assembly further includes an upper insulating member, including a first annular portion, a second annular portion and a third annular portion connected to each other, the first annular portion being inserted into the first pole hole and surrounding the outer periphery of the first column section, and the second annular portion and the third annular portion being located on the side where the first surface of the end plate is located; The pole further has a third column section, the first column section being connected between the second column section and the third column section, the cross-sectional area of the third column section being larger than that of the first column section, the third annular portion surrounding the outer periphery of the third column section, and the second annular portion being disposed between the third column section and the end plate; At least one second groove is provided on the side of the second annular portion facing the third column section, and the second groove extends from the inner ring surface of the first annular portion to the inner ring surface of the third annular portion.

4. The end cap assembly according to claim 3, characterized in that, The positive projections of the first groove and the second groove on the plane where the first surface is located are arranged in a staggered manner.

5. The end cap assembly according to claim 1, characterized in that, The end cover assembly further includes a lower insulating member located on the side where the second surface of the end plate is located, and the lower insulating member has an annular flange, and the annular flange is located on the side of the connecting member facing the annular step surface; The annular flange has a third pole hole coaxially arranged with the first pole hole, and the first column section is inserted into the third pole hole; At least one third groove is provided on the side of the annular flange facing the connecting member, and the third groove communicates with the third pole hole; The positive projection of the third groove on the plane where the first surface is located is the third projection (S3), the positive projection of the connecting member on the plane where the first surface is located is the fourth projection (S4), there is an overlapping area between the third projection (S3) and the fourth projection (S4), and a part of the third projection (S3) extends beyond the outer contour line of the fourth projection (S4).

6. The end cap assembly according to claim 5, characterized in that, The positive projections of the first groove and the third groove on the plane where the first surface is located are arranged in a staggered manner.

7. The end cap assembly according to claim 5, wherein The end plate further has a sunken groove, the sunken groove is recessed from the second surface along the thickness direction of the end plate towards the first surface, the first pole hole penetrates through the bottom surface of the sunken groove; the annular flange is located in the sunken groove; The lower insulating member further includes an insulating sheet and a fourth annular portion, the insulating sheet is located on the side where the second surface of the end plate is located, and has a through hole, the through hole penetrates through the insulating sheet along the thickness direction of the end plate, and the connecting member is limited in the through hole; The fourth annular portion is connected to the edge of the through hole, and protrudes from the side surface of the insulating sheet facing the end plate, the fourth annular portion is located in the sunken groove, and surrounds the outer circumference of the connecting member; The annular flange protrudes from the inner ring surface of the fourth annular portion, and the third groove extends from the hole wall of the third pole hole to the inner ring surface of the fourth annular portion.

8. The end cap assembly according to claim 1, characterized in that, The end cover assembly further includes a sealing member, the sealing member includes a sealing ring and a plurality of protrusions, the sealing ring is sleeved on the outer circumference of the pole, and is located between the end plate and the connecting member, and the plurality of protrusions protrude from the inner ring surface of the sealing ring and are arranged along the circumferential direction of the sealing ring.

9. The end cap assembly according to claim 1, characterized in that, The end cover assembly further includes a sealing ring, the sealing ring is sleeved on the outer circumference of the pole, and is located between the end plate and the connecting member; the positive projection of the sealing ring on the plane where the first surface is located is the fifth projection (S5); Wherein, the first projection (S1) does not coincide with the fifth projection (S5); or, there is a coincident sixth projection (S6) between the first projection (S1) and the fifth projection (S5), and the maximum dimension of the sixth projection (S6) along the radial direction of the fifth projection (S5) is less than one-half of the ring width of the fifth projection (S5).

10. An energy storage device, characterized in that, Comprising: A housing, including a receiving cavity with an opening; An electrode assembly, accommodated in the receiving cavity; And The end cover assembly according to any one of claims 1 to 9, the end cover assembly closing the opening of the receiving cavity.

11. An electrical equipment, characterized in that, Including the energy storage device according to claim 10, the energy storage device supplying power to the electrical equipment.

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