Top cover assembly, battery and energy storage device

Abstract

The invention provides a top cover assembly, a battery and an energy storage device. Comprising a top cover, lower plastic, a pole and a sealing ring, wherein the top cover is provided with a first hole; the lower plastic and the top cover are arranged in a stacked mode, the lower plastic is provided with a second hole and a groove, the second hole penetrates through the lower plastic in the thickness direction of the lower plastic and is coaxially arranged and communicated with the first hole, the inner wall of the second hole is matched with part of the surface, facing the lower plastic, of the top cover to form a first step structure, and an opening of the groove is located in the surface, deviating from the top cover, of the lower plastic. The groove is located on the periphery of the second hole and communicated with the second hole, and the side wall of the groove and the bottom wall of the groove are matched to form a second step structure; the pole penetrates through the first hole and the second hole; the sealing ring is arranged on the pole in a sleeving mode and located in the first hole, the second hole and the groove, the sealing ring located in the second hole abuts against the first step structure, and the sealing ring located in the groove abuts against the second step structure. According to the technical scheme, conduction of the top cover and the pole can be avoided, and the safety performance of the electrode assembly is guaranteed.

Description

Technical Field

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

[0002] With the development of green energy, recyclable batteries are becoming increasingly popular. A battery consists of an electrode assembly, a casing, and a top cover assembly. The electrode assembly is located within the housing formed by the casing and the top cover assembly. The top cover assembly includes a top cover and a terminal. The terminal is mounted on the top cover. Currently, the gap between the top cover and the terminal is susceptible to electrolyte intrusion. This reduces insulation between the top cover and the terminal, potentially leading to electrical conduction between the top cover and the terminal, and degrading the safety of the electrode assembly. Summary of the Invention

[0003] The embodiments of the present application provide a top cover assembly, a battery, and an energy storage device, which can prevent the top cover and the electrode column from being conductive, thereby ensuring the safety performance of the electrode assembly.

[0004] In a first aspect, the present application provides a top cover assembly, comprising a top cover, a lower plastic, a pole and a sealing ring: The top cover is provided with a first hole, and the first hole penetrates the top cover along the thickness direction of the top cover; The lower plastic is stacked with the top cover, and the lower plastic is provided with a second hole and a groove. The second hole penetrates the lower plastic along the thickness direction of the lower plastic and is coaxially arranged and connected to the first hole. The inner wall of the second hole cooperates with the portion of the surface of the top cover facing the lower plastic to form a first step structure. The opening of the groove is located on the surface of the lower plastic facing away from the top cover. The groove is located on the periphery of the second hole and is connected to the second hole. The side walls of the groove cooperate with the bottom wall of the groove to form a second step structure. The pole is passed through the first hole and the second hole; The sealing ring is sleeved on the pole and located in the first hole, the second hole and the groove. The sealing ring located in the second hole abuts against the first step structure, and the sealing ring located in the groove abuts against the second step structure.

[0005] It is understandable that in the related art, when the top cover assembly is assembled, there is good insulation performance between the pole and the top cover. However, when the top cover assembly comes into contact with the electrolyte, the electrolyte will invade the area where the pole of the top cover assembly is located. Due to errors such as the manufacturing tolerances of the various components in the top cover assembly and the assembly tolerances during assembly, a gap will be formed between the radial direction of the sealing ring and the inner wall of the pole hole of the lower plastic. When there is electrolyte in this gap, it is easy to sharply reduce the insulation performance between the top cover and the pole, resulting in reduced safety of the electrode assembly. In addition, foreign matter such as metal chips or water vapor in the middle can easily invade this gap, causing the insulation between the pole and the top cover to be further reduced.

[0006] Therefore, in the embodiment of the present application, by making the sealing ring located in the second hole of the lower plastic abut against the first step structure, and the sealing ring located in the groove of the lower plastic abut against the second step structure, the sealing ring can form multiple steps between the top cover, the lower plastic and the pole, which can not only avoid the interference of burrs at the corners of the pole and the corners of the lower plastic, but also increase the creepage distance. It can also make the sealing ring effectively seal the gap enclosed by the lower plastic, the sealing ring and the top cover, blocking the flow path of the electrolyte entering the pole and the top cover through this gap, avoiding the problem of the pole and the top cover being connected due to contact with the electrolyte, causing a short circuit, which is beneficial to improving the sealing performance of the top cover assembly and the safety performance of the electrode assembly.

[0007] In one possible embodiment, the sealing ring includes a sealing ring body, a first skirt and a second skirt. The sealing ring body is sleeved on the pole and is located in the first hole and the second hole. The first skirt is connected to the outer edge of the sealing ring body and is located in the second hole. The first skirt is abutted against the first step structure. The second skirt is connected to the outer edge of the first skirt and is located in the groove. The second skirt is abutted against the second step structure.

[0008] In a possible embodiment, the top cover is further provided with a mounting groove, the opening of the mounting groove is located on the surface of the top cover away from the lower plastic, the mounting groove is located outside the first hole and communicates with the first hole; The top cover assembly also includes an upper plastic, which includes an upper plastic body and an extension portion that are connected to each other. The upper plastic body and the extension portion are both sleeved on the outside of the pole. Part of the upper plastic body is located in the mounting groove and the first hole. The extension portion is located in the first hole, and one end away from the upper plastic body is in contact with the sealing ring.

[0009] In a possible embodiment, the top cover assembly further includes a pressing block, the pressing block is sleeved on the pole and connected to the pole, and at least a portion of the pressing block is embedded in the upper plastic; The pole includes a base, a first sub-column and a second sub-column, a portion of the base is surrounded by the lower plastic, and another portion of the base protrudes relative to the lower plastic in a direction away from the top cover, and the base also abuts against an end of the sealing ring away from the upper plastic. The first sub-column is coaxially arranged and connected to the base, the first sub-column is surrounded by the upper plastic and the sealing ring, and is located between the pressure block and the base, the second sub-column is coaxially arranged with the first sub-column, and is connected to an end of the first sub-column away from the base, and at least a portion of the second sub-column is surrounded by the pressure block.

[0010] In one possible embodiment, the height of the first sub-column is a first height H1, the height of the upper plastic between the pressing block and the base is a second height H2, and the height of the sealing ring between the pressing block and the base is a third height H3; The first height H1, the second height H2 and the third height H3 satisfy the relationship: H3

[0011] In one possible implementation, a protruding height of the pole relative to the surface of the pressing block facing away from the upper plastic is a fourth height H4, a height of the sealing ring between the top cover and the base is a fifth height H5, and the fourth height H4 is less than or equal to the fifth height H5.

[0012] In a possible embodiment, the top cover is provided with a limiting groove, the opening of the limiting groove is located on the surface of the top cover facing the lower plastic, the limiting groove is located outside the first hole, and is connected to the first hole; The lower plastic includes a lower plastic body and a convex portion. The lower plastic body is stacked with the top cover. The convex portion is connected to the surface of the lower plastic body facing the top cover. The convex portion and the lower plastic body are arranged to form the second hole and the groove. The convex portion is located in the limiting groove and abuts against both the first skirt and the second skirt.

[0013] In a possible implementation manner, the top surface of the protrusion contacts the bottom wall of the limiting groove, and the outer side surface of the protrusion contacts the side wall of the limiting groove.

[0014] In a possible implementation manner, an angle between the bottom wall of the limiting groove and the side wall of the limiting groove is an obtuse angle.

[0015] In one possible embodiment, the lower plastic is further provided with a receiving groove, the opening of the receiving groove is located on the surface of the lower plastic facing away from the top cover, the receiving groove is provided on the periphery of the limiting groove and is connected to the limiting groove, and part of the pole is located in the receiving groove and abuts against the sealing ring. ​

[0016] In one possible embodiment, the pole includes a column and a base, the column and the base are coaxially arranged and connected, part of the column is located in the first hole and the second hole, and part of the base is located in the accommodating groove, the limiting groove and the second hole, and the base is in contact with the bottom wall of the accommodating groove or has a gap.

[0017] In a second aspect, the present application also provides a battery, which includes an electrode assembly, a shell and a top cover assembly as described above, wherein the top cover assembly is connected to the shell and is arranged together with the shell to form a receiving space, and the electrode assembly is located in the receiving space.

[0018] In a third aspect, the present application further provides an energy storage device, which includes the battery as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic structural diagram of an energy storage system provided in an embodiment of the present application; Figure 2 This is a schematic structural diagram of a battery provided in an embodiment of the present application; Figure 3 This is a structural schematic diagram of a top cover assembly provided in an embodiment of the present application; Figure 4 yes Figure 3 A schematic diagram of the exploded structure of the top cover assembly shown; Figure 5 yes Figure 3 A schematic structural diagram of the top cover of the top cover assembly shown; Figure 6 It is along Figure 5 A schematic cross-sectional view of a portion of the top cover structure obtained by cutting along the cutting line BB shown; Figure 7 It is along Figure 3 A schematic cross-sectional view of a portion of the top cover assembly obtained by cutting along the cutting line AA shown; Figure 8 yes Figure 3 A schematic structural diagram of the lower plastic portion of the top cover assembly at an angle is shown; Figure 9 yes Figure 3 A schematic structural diagram of the lower plastic portion of the top cover assembly from another angle; Figure 10 yes Figure 7 An enlarged schematic diagram of region Q is shown; Figure 11 yes Figure 3 A schematic structural diagram of a pole of the top cover assembly at an angle shown; Figure 12 yes Figure 3A schematic structural diagram of the sealing ring of the top cover assembly at one angle is shown; Figure 13 yes Figure 3 A schematic structural diagram of the sealing ring of the top cover assembly shown in another angle.

[0020] Reference numerals: Energy storage system 400, high-voltage cable 410, first power conversion device 420, second power conversion device 430, energy storage device 300, battery 200, top cover assembly 100, housing 210, electrode assembly 220, top cover 10, upper plastic 20, lower plastic 30, pole 40, sealing ring 50, pressing block 60, explosion-proof valve assembly 70, first surface 11, second surface 12, first hole 13, mounting groove 14, limiting groove 15, upper plastic body 2 1. Extension 22, first through hole 23, assembly groove 211, second through hole 61, explosion-proof valve 71, explosion-proof valve protection plate 72, second hole 31, first step structure T1, groove 32, second step structure T2, accommodating groove 33, lower plastic body 34, protrusion 35, third surface 341, fourth surface 342, column 41, base 42, first sub-column 411, second sub-column 412, sealing ring body 51, first skirt 52, second skirt 53. DETAILED DESCRIPTION

[0021] For ease of understanding, the terms involved in the embodiments of the present application are first explained.

[0022] And / or: It is just a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone.

[0023] Multiple: refers to two or more than two.

[0024] Connection: should be understood in a broad sense. For example, A and B are connected, which can be either directly connected or indirectly connected through an intermediary.

[0025] The specific implementation of the present application will be clearly described below with reference to the accompanying drawings.

[0026] Embodiments of the present application provide a top cover assembly, a battery, and an energy storage device.

[0027] Since the energy people need is highly time- and space-dependent, in order to rationally utilize energy and improve energy utilization, it is necessary to use a medium or device to store one form of energy in the same form or convert it into another form of energy, and then release it in a specific form based on future application needs. Currently, the main way to generate green electricity is to develop green energy such as photovoltaics and wind power to replace fossil energy. Currently, the generation of green electricity generally relies on photovoltaics, wind power, and hydropower. However, wind and solar energy are generally intermittent and highly volatile, which can cause grid instability, insufficient electricity during peak hours, and excessive electricity during off-peak hours. Unstable voltage can also damage the power supply. Therefore, problems may arise due to insufficient electricity demand or insufficient grid capacity. To solve these problems, energy storage is necessary. This means converting electrical energy into other forms of energy through physical or chemical means and storing them. When needed, this energy is converted back into electrical energy and released. Simply put, energy storage is like a large "power bank", storing electricity when photovoltaic and wind energy are sufficient and releasing the stored electricity when needed.

[0028] Taking electrochemical energy storage as an example, this solution provides an energy storage device for use in energy storage systems. The energy storage device is equipped with a group of chemical batteries, which mainly use the chemical elements in the batteries as energy storage media. The charging and discharging process is accompanied by chemical reactions or changes in the energy storage medium. Simply put, the electricity generated by wind and solar energy is stored in the chemical battery. When the use of external electricity reaches its peak, the stored electricity is released for use, or transferred to places where electricity is scarce for use.

[0029] Currently, energy storage (i.e., energy storage) has a wide range of application scenarios, including power generation side energy storage, grid side energy storage, and power consumption side energy storage. The corresponding types of energy storage devices include: (1) Large-scale energy storage power stations applied to wind power and photovoltaic power stations can help renewable energy generation meet grid connection requirements and improve the utilization rate of renewable energy. As a high-quality active / reactive power supply on the power supply side, energy storage power stations can achieve load matching of electricity in time and space, enhance the capacity to absorb renewable energy, reduce instantaneous power changes, reduce the impact on the power grid, improve the absorption of new energy generation, and are of great significance in grid system backup, alleviating peak load power supply pressure, and peak and frequency regulation. (2) Energy storage containers used on the grid side are mainly used for peak shaving, frequency regulation, and relief of grid congestion. They can realize peak shaving and valley filling of electricity load, that is, charging the energy storage battery when the electricity load is low and releasing the stored electricity during the peak period, thereby achieving a balance between electricity production and consumption; (3) Small energy storage cabinets used on the power consumption side, whose main functions are self-generation and self-use of electricity, peak-valley price arbitrage, capacity cost management, and improving power supply reliability. Depending on the application scenario, power consumption side energy storage can be divided into industrial and commercial energy storage cabinets, household energy storage devices, energy storage charging piles, etc., which are generally used in conjunction with distributed photovoltaics. Considering that photovoltaics generate electricity during the day, and users generally have higher loads at night, by configuring energy storage, photovoltaic power can be better utilized, the level of self-generation and self-use can be improved, and electricity costs can be reduced. In addition, communication base stations, data centers and other fields need to configure energy storage for backup power.

[0030] In some embodiments, see Figure 1 , Figure 1 Schematic diagram of the structure of the energy storage system 400 provided in the embodiment of the present application. Figure 1 In the embodiment of the present application, the shared energy storage scenario on the power generation / distribution side is used as an example for description. The energy storage device 300 of the present application is not limited to the energy storage scenario on the power generation / distribution side.

[0031] An embodiment of the present application provides an energy storage system 400 . The energy storage system 400 includes a high-voltage cable 410 , a first power conversion device 420 , a second power conversion device 430 , and an energy storage device 300 .

[0032] In some embodiments of the power generation side scenario, the second power conversion device 430 can be a wind power conversion device. Since the power generated by wind power conversion is volatile, random, and intermittent, the unstable power output by the wind power conversion device can be first stored in the energy storage device 300 by connecting to the grid. The energy storage device 300 is connected to the high-voltage cable and outputs smooth power to the power distribution network for use, thereby achieving peak load regulation and frequency regulation and stable operation of the power grid. Alternatively, the wind power conversion device is always connected to the high-voltage cable. Under normal power generation conditions, the power output by the wind power conversion device is supplied to the power distribution network for use through the high-voltage cable. When the current power load is low and the wind power conversion device generates excess power, the excess power is first stored in the energy storage device 300 to improve the problem of new energy power generation and consumption. When the power load is high, the power grid issues a command to transmit the electricity stored in the energy storage device 300 in conjunction with the high-voltage cable 410 in a grid-connected mode to the power consumption side, providing peak-shaving, frequency regulation, standby and other services for the power grid operation, giving full play to the peak-shaving role of the power grid, promoting peak-shaving and valley-filling of the power grid, and alleviating the power supply pressure of the power grid.

[0033] In some embodiments on the distribution network side, the first power conversion device 420 may be a photovoltaic power conversion device. The energy storage device 300 is connected to the high-voltage cable 410 and installed between the downstream portion of the high-voltage cable 410 and the user load. The power output by the photovoltaic power conversion device is stored in the energy storage device 300, providing a timely response and backup power source in the event of a power grid / distribution network failure. Alternatively, this device can alleviate congestion in the high-voltage cable 410 transmission line and provide power supply support during planned grid expansion to mitigate the economic pressures associated with grid / distribution capacity expansion.

[0034] Optionally, the first power conversion device 420 may include but is not limited to a wind power conversion device, and the second power conversion device 430 may include but is not limited to a photovoltaic power conversion device. The first power conversion device 420 and the second power conversion device 430 can convert at least one of solar energy, light energy, wind energy, thermal energy, tidal energy, biomass energy and mechanical energy into electrical energy.

[0035] Optionally, the energy storage device 300 may include but is not limited to energy storage application scenarios such as energy storage power stations, hydropower / thermal / wind power generation systems, solar power generation systems, mobile power systems, smart home systems or temporary power supply systems, and may also be used in data centers, aerospace, charging piles, electric vehicles and other fields.

[0036] Optionally, the energy storage device 300 may include, but is not limited to, a single cell 200, or a battery integrated system such as a battery module, battery pack, battery cluster, mobile power supply, energy storage cabinet / container, etc. comprised of single cells 200. The actual application form of the energy storage device 300 provided in the embodiments of this application may include, but is not limited to, the products listed above, and may also include other application forms. This embodiment of this application does not impose strict restrictions on the application form of the energy storage device 300. This embodiment of this application only uses the energy storage device 300 as a multi-core battery 200 as an example for description.

[0037] Optionally, when the energy storage device 300 is a single battery 200, the energy storage device 300 may be, but is not limited to, at least one of a cylindrical battery, a square battery, a prismatic battery, or batteries of other shapes.

[0038] Optionally, the battery 200 may be a secondary battery. A secondary battery is a battery cell that can be recharged to activate the active material after discharge and continue to be used. The battery cell may 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, or the like, and the embodiments of this application do not specifically limit this.

[0039] See also Figure 2 , Figure 2It is a structural diagram of a battery 200 provided in an embodiment of the present application.

[0040] The battery 200 may include a top cap assembly 100, a housing 210, and an electrode assembly 220. The top cap assembly 100 is connected to the housing 210 and forms a housing space with the housing 210. The electrode assembly 220 is located within the housing space. For example, the top cap assembly 100 may be welded to the housing 210. The housing 210 may be made of a metal material, such as an aluminum alloy. The battery 200 may be a cylindrical battery 200 or a square battery 200.

[0041] The electrode assembly 220 may include at least two electrode cores (not shown). The at least two electrode cores are arranged in sequence along the thickness direction of the battery 200. The provision of multiple electrode cores can increase the capacity of the battery 200, thereby allowing the battery 200 to be used for a long time, thereby increasing the applicable scenarios of the battery 200. Each electrode core may include a winding core, a first electrode tab, and a second electrode tab. The first electrode tab and the second electrode tab are both connected to the winding core. The polarity of the first electrode tab and the second electrode tab are opposite, one is a positive electrode tab and the other is a negative electrode tab.

[0042] It should be noted that Figure 2 The purpose is only to schematically describe the connection relationship between the top cover assembly 100, the housing 210 and the electrode assembly 220, and it does not specifically limit the connection position, specific structure and quantity of each component. The structure shown in the embodiment of the present application does not constitute a specific limitation on the battery 200. In other embodiments of the present application, the battery 200 may include Figure 2 More or fewer components may be shown, or some components may be combined or separated, or the components may be arranged differently. Figure 2 The components shown can be implemented in hardware, software, or a combination of software and hardware.

[0043] Please refer to Figure 3 and Figure 4 , Figure 3 is a structural diagram of a top cover assembly 100 provided in an embodiment of the present application. Figure 4 yes Figure 3 The exploded structural diagram of the top cover assembly 100 is shown.

[0044] In the embodiment of the present application, the top cover assembly 100 may include a top cover 10 , an upper plastic 20 , a lower plastic 30 , a pole 40 , a sealing ring 50 , a pressing block 60 and an explosion-proof valve assembly 70 .

[0045] Both the upper plastic 20 and the lower plastic 30 are mounted on the top cover 10. The upper plastic 20 is mounted on one side of the top cover 10 in the thickness direction (Z direction in the figure), and the lower plastic 30 is mounted on the other side of the top cover 10 in the thickness direction. The lower plastic 30 and the upper plastic 20 are respectively protruded from two opposing surfaces in the thickness direction of the top cover 10. The number of upper plastics 20 can be two. The two upper plastics 20 are installed on opposite sides of the top cover 10 in the length direction (X direction in the figure) with a spacing.

[0046] The pole 40 is mounted on the top cover 10, the upper plastic 20, and the lower plastic 30, and is insulated from the top cover 10 by the upper plastic 20, the lower plastic 30, and the sealing ring 50. The pole 40 can also serve as an electrode lead for the battery 200 to achieve electrical connection between the battery 200 and external devices. The number of poles 40 can be two. The two poles 40 can be a negative pole 40 and a positive pole 40, respectively. The two poles 40 can be spaced apart in the longitudinal direction of the top cover 10. Each pole 40 is mounted on the lower plastic 30, the top cover 10, an upper plastic 20, and a pressing block 60.

[0047] The sealing ring 50 is disposed on the outside of the electrode 40 and is located between the lower plastic 30 and the electrode 40, as well as between the top cover 10 and the electrode 40. The sealing ring 50 can be used to seal the gap between the top cover 10 and the electrode 40, preventing electrolyte from invading this gap and reducing the insulation between the top cover 10 and the electrode 40 and the safety of the electrode assembly 220. There can be two sealing rings 50. One sealing ring 50 is disposed on the positive electrode 40, and the other sealing ring 50 is disposed on the negative electrode 40.

[0048] The pressing block 60 is mounted on the upper plastic 20 and is sleeved on the outside of the terminal 40 and electrically connected to the terminal 40. There can be two pressing blocks 60. The two pressing blocks 60 are respectively mounted on the two upper plastics 20 and are electrically connected to the two terminal 40.

[0049] The explosion-proof valve assembly 70 is mounted on the top cover 10 and is used to protect the battery 200 from pressure relief.

[0050] Please refer to Figure 5 and Figure 6 , Figure 5 yes Figure 3 The schematic structural diagram of the top cover 10 of the top cover assembly 100 is shown in FIG. Figure 6 It is along Figure 5 The section line BB shown is a schematic cross-sectional view of a portion of the structure of the top cover 10 .

[0051] The top cover 10 may include a first surface 11 and a second surface 12. The second surface 12 and the first surface 11 are disposed opposite each other in the thickness direction (Z direction in the figure) of the top cover 10. The first surface 11 may face away from the electrode assembly 220, and the second surface 12 may face toward the electrode assembly 220.

[0052] The top cover 10 may be provided with a first hole 13. The first hole 13 may penetrate the top cover 10 along its thickness. Specifically, the first hole 13 may penetrate both the first surface 11 and the second surface 12 of the top cover 10. There may be two first holes 13. The two first holes 13 may be spaced apart in the length direction (X direction in the figure) of the top cover 10.

[0053] The top cover 10 may be provided with a mounting groove 14. The opening of the mounting groove 14 may be located on the first surface 11. The mounting groove 14 may be formed by being recessed from the first surface 11 toward the interior of the top cover 10 and be connected to the first hole 13. The depth of the mounting groove 14 may be less than the depth of the first hole 13. The length of the mounting groove 14 along the longitudinal direction of the top cover 10 may be greater than the length of the first hole 13 along the longitudinal direction of the top cover 10. The length of the mounting groove 14 along the width direction of the top cover 10 may be greater than the length of the first hole 13 along the width direction of the top cover 10. Among them, the mounting groove 14 may be a blind groove. The number of the mounting grooves 14 may be two, and the two mounting grooves 14 may be spaced apart in the longitudinal direction of the top cover 10. Each mounting groove 14 is connected to a first hole 13.

[0054] The top cover 10 may also be provided with a limiting groove 15. The opening of the limiting groove 15 may be located on the second surface 12 of the top cover 10. The limiting groove 15 may be formed by being recessed from the second surface 12 toward the interior of the top cover 10. The limiting groove 15 may be located on the periphery of the first hole 13 and be connected to the first hole 13. The depth of the limiting groove 15 may be less than the depth of the first hole 13. The limiting groove 15 may be a blind groove. The number of the limiting grooves 15 may be two. The two limiting grooves 15 may be spaced apart in the length direction of the top cover 10. Each limiting groove 15 is connected to one first hole 13.

[0055] The angle α between the bottom wall of the limiting groove 15 and the side wall of the limiting groove 15 can be an obtuse angle. The bottom wall of the limiting groove 15 refers to the wall surface in the limiting groove 15 that is arranged opposite to the opening of the limiting groove 15 in the thickness direction of the top cover 10. The side wall of the limiting groove 15 refers to the wall surface in the limiting groove 15 that is connected between the bottom wall of the limiting groove 15 and the opening of the limiting groove 15. For example, the angle between the bottom wall of the limiting groove 15 and the side wall of the limiting groove 15 can be 135°. Of course, in some other embodiments, the angle between the bottom wall of the limiting groove 15 and the side wall of the limiting groove 15 can also be a right angle or an acute angle, and there is no strict limitation on this.

[0056] Please refer to Figure 4 and Figure 7 , Figure 7 It is along Figure 3 The section line AA shown is a schematic cross-sectional view of a portion of the structure of the top cover assembly 100 .

[0057] The upper plastic 20 can be sleeved on the pole 40 and located between the top cover 10 and the pole 40 and between the pressing block 60 and the top cover 10. Specifically, the upper plastic 20 can include an upper plastic body 21 and an extension 22. The upper plastic body 21 and the extension 22 can be coaxially arranged and connected.

[0058] The upper plastic portion 20 may be provided with a first through-hole 23. The first through-hole 23 may extend through the upper plastic portion 20 along its thickness (Z-direction in the figure). Specifically, the first through-hole 23 may extend through the upper plastic portion 21 and the extension portion 22 along its thickness. The first through-hole 23 may be coaxially arranged with and communicate with the first hole 13 of the top cover 10.

[0059] The upper plastic body 21 can be installed in the mounting groove 14 of the top cover 10 and sleeved around the outside of the pole 40. A portion of the upper plastic body 21 is located within the mounting groove 14 and the first hole 13 of the top cover 10, while the remaining portion of the upper plastic body 21 protrudes away from the lower plastic member 30 relative to the first surface 11 of the top cover 10. In other words, the upper plastic body 21 can be located on the side of the top cover 10 facing away from the lower plastic member 30. The shape of the upper plastic body 21 can be adapted to the shape of the mounting groove 14 of the top cover 10 to better secure the upper plastic member 20 relative to the top cover 10.

[0060] The upper plastic body 21 may be provided with a mounting groove 211. The opening of the mounting groove 211 may be located on the surface of the upper plastic body 21 facing away from the extension 22. The mounting groove 211 may be recessed from the surface of the upper plastic body 21 facing away from the extension 22 toward the interior of the upper plastic body 20. The mounting groove 211 may be connected to the first through hole 23.

[0061] For example, the number of first through holes 23 can be two. The two first through holes 23 can be respectively provided in the two upper plastics 20. The number of assembly grooves 211 can be two. The two assembly grooves 211 can be respectively provided in the two upper plastics 20. Each assembly groove 211 is connected to one first through hole 23.

[0062] One end of the extension portion 22 is fixedly connected to the upper plastic body 21, and the other end of the extension portion 22 extends away from the upper plastic body 21. The extension portion 22 can be located in the first hole 13 of the top cover 10 and also sleeved on the outer side of the pole 40.

[0063] The pressing block 60 can be located on one side of the first surface 11 of the top cover 10. At least a portion of the pressing block 60 can be embedded in the upper plastic 20. Specifically, the pressing block 60 can be installed in the assembly groove 211 of the upper plastic 20. The pressing block 60 can be sleeved on the pole 40 and connected to the pole 40. The pressing block 60 and the pole 40 can be connected by riveting to form an integrated structure. Furthermore, after the pressing block 60 and the pole 40 are riveted together, the pressing block 60 and the pole 40 can be welded together.

[0064] The pressing block 60 may be provided with a second through hole 61. The second through hole 61 may extend through the pressing block 60 along its thickness direction (Z direction in the figure). The second through hole 61 may be coaxially arranged with and communicate with the first through hole 23 of the upper plastic 20 and the first hole 13 of the top cover 10.

[0065] The explosion-proof valve assembly 70 may include an explosion-proof valve 71 and an explosion-proof valve protection sheet 72. The explosion-proof valve 71 and the explosion-proof valve protection sheet 72 may both be mounted on the top cover 10 and arranged sequentially in the thickness direction of the top cover 10. The explosion-proof valve protection sheet 72 may also cover the explosion-proof valve 71.

[0066] Please refer to Figure 8 and Figure 9 , Figure 8 yes Figure 3 The schematic structural diagram of the lower plastic 30 of the top cover assembly 100 is shown at an angle. Figure 9 yes Figure 3 The structure diagram of the lower plastic 30 of the top cover assembly 100 is shown from another angle.

[0067] The lower plastic member 30 is mounted on one side of the second surface 12 of the top cover 10 and is stacked with the top cover 10. The lower plastic member 30 may be provided with a second hole 31. The second hole 31 may extend through the top cover 10 along the thickness of the lower plastic member 30. The second hole 31 may be coaxially arranged with and connected to the first hole 13 of the top cover 10. There may be two second holes 31, and the two second holes 31 may be spaced apart along the length (X direction in the figure) of the lower plastic member 30.

[0068] Please refer to Figure 7 、 Figure 9 and Figure 10 , Figure 10 yes Figure 7 An enlarged schematic diagram of region Q is shown.

[0069] The inner wall of the second hole 31 can cooperate with the portion of the top cover 10 surface facing the lower plastic 30 to form a first step structure T1. Specifically, the inner wall of the second hole 31 can form two stepped surfaces of the first step structure T1 with the portion of the top cover 10 surface facing the lower plastic 30. The portion of the top cover 10 surface facing the lower plastic 30 can be a portion of the second surface 12 or a portion of the bottom wall of the retaining groove 15. There can be two first step structures T1, spaced apart on either side of the length of the lower plastic 30.

[0070] The lower plastic 30 may be provided with a groove 32. The opening of the groove 32 may be located on the surface of the lower plastic 30 facing away from the top cover 10. The groove 32 may be formed by being recessed from the surface of the lower plastic 30 facing away from the top cover 10 toward the interior of the lower plastic 30. The groove 32 may be located on the periphery of the second hole 31 and be connected to the second hole 31. That is, the groove 32 may be annular and arranged around the periphery of the second hole 31. The depth of the groove 32 may be less than the depth of the second hole 31. The groove 32 may be a blind groove. The number of grooves 32 may be two. The two grooves 32 may be spaced apart in the length direction of the lower plastic 30. Each groove 32 is connected to one second hole 31.

[0071] The sidewalls and bottom wall of the groove 32 cooperate to form a second step structure T2. Specifically, the sidewalls and bottom wall of the groove 32 each form two stepped surfaces of the second step structure T2. The bottom wall of the groove 32 refers to the wall surface of the groove 32 that is opposite the opening of the groove 32 in the thickness direction of the lower plastic 30. The sidewalls of the groove 32 refer to the wall surface of the groove 32 that connects the bottom wall of the groove 32 to the opening of the groove 32.

[0072] The lower plastic 30 may also be provided with a receiving groove 33. The opening of the receiving groove 33 may be located on the surface of the lower plastic 30 facing away from the top cover 10. The receiving groove 33 may be formed by being recessed from the surface of the lower plastic 30 facing away from the top cover 10 toward the interior of the lower plastic 30. The receiving groove 33 may be provided on the periphery of the limiting groove 15 and be connected to the limiting groove 15. That is, the receiving groove 33 may be annular and arranged around the periphery of the limiting groove 15. The depth of the receiving groove 33 may be less than the depth of the groove 32. The receiving groove 33 may be a blind groove. The number of the receiving grooves 33 may be two. The two receiving grooves 33 may be spaced apart in the length direction of the lower plastic 30. Each receiving groove 33 is connected to one groove 32.

[0073] Please refer to Figure 7 、 Figure 8 and Figure 10The lower plastic 30 may include a lower plastic body 34 and a protrusion 35. The lower plastic body 34 may be stacked with the top cover 10. The lower plastic body 34 may include a third surface 341 and a fourth surface 342. The fourth surface 342 and the third surface 341 may be disposed opposite each other in the thickness direction (Z direction in the figure) of the lower plastic 30. The third surface 341 may face the top cover 10, and the fourth surface 342 may face the electrode assembly 220.

[0074] The protrusion 35 is connected to the third surface 341 of the lower plastic body 34 and projects relative to the third surface 341 of the lower plastic body 34 toward the top cover 10. The protrusion 35 can be positioned within the retaining groove 15 of the top cover 10. The protrusion 35 and the lower plastic body 34 enclose the second hole 31 and groove 32 of the lower plastic body 30 described above. The lower plastic body 34 is also provided with the aforementioned receiving groove 33.

[0075] It is understood that by providing the retaining groove 15 on the top cover 10 and the protrusion 35 on the lower plastic 30, and positioning the protrusion 35 of the lower plastic 30 within the retaining groove 15 of the top cover 10, the internal space of the top cover 10 can be utilized to accommodate a portion of the lower plastic 30, thereby facilitating a thinner and lighter top cover assembly 100. Furthermore, this allows for a tighter connection between the top cover 10 and the lower plastic 30, thereby improving the strength and reliability of the connection between the two.

[0076] Furthermore, the angle between the top surface of the protrusion 35 and the outer side surface of the protrusion 35 can be an obtuse angle. The top surface of the protrusion 35 can contact the bottom wall of the retaining groove 15 of the top cover 10, while the outer side surface of the protrusion 35 contacts the sidewall of the retaining groove 15 of the top cover 10. With this arrangement, the contact area between the protrusion 35 and the retaining groove 15 of the top cover 10 can be further increased, ensuring a fully tight fit between the lower plastic 30 and the top cover 10, thereby enhancing the connection strength between the top cover 10 and the lower plastic 30.

[0077] Please refer to Figure 10 and Figure 11 , Figure 11 yes Figure 3 The structure diagram of the pole 40 of the top cover assembly 100 is shown at an angle.

[0078] The pole 40 can include a body 41 and a base 42. A portion of the base 42 is enclosed by the lower plastic 30, while another portion of the base 42 protrudes from the lower plastic 30, away from the top cover 10. The body 41 and base 42 can be coaxially arranged and connected. The body 41 can be inserted through the second through-hole 61 of the pressure block 60, the first through-hole 23 of the upper plastic 20, the first hole 13 of the top cover 10, and the second hole 31 of the lower plastic 30. The projection of the body 41 in the height direction of the pole 40 can completely fall onto the base 42.

[0079] Specifically, the column 41 may include a first sub-column 411 and a second sub-column 412. The first sub-column 411 and the base 42 may be coaxially arranged and connected. The second sub-column 412 may be coaxially arranged with the first sub-column 411 and connected to the end of the first sub-column 411 away from the base 42. In other words, the first sub-column 411 may be connected between the second sub-column 412 and the base 42. In other words, in the height direction of the pole 40 (the Z direction in the figure), the base 42, the first sub-column 411, and the second sub-column 412 may be connected in sequence.

[0080] The first sub-pillar 411 can be surrounded by the upper plastic 20 and the sealing ring 50 and located between the pressing block 60 and the base 42. At least a portion of the second sub-pillar 412 is surrounded by the pressing block 60. The first sub-pillar 411 can be located in the first through-hole 23 of the upper plastic 20, the first hole 13 of the top cover 10, and the second hole 31 of the lower plastic 30. The second sub-pillar 412 can be located in the first through-hole 23 of the upper plastic 20 and the second through-hole 61 of the pressing block 60.

[0081] The base 42 can be located on the side of the lower plastic 30 facing away from the top cover 10 (i.e., on the side of the fourth surface 342 of the lower plastic 30), forming a gap between the lower plastic 30 and the top cover 10. The gap formed between the base 42, the lower plastic 30, and the top cover 10 can be disposed around the column 41. That is, in the Z direction, the gap formed between the base 42, the lower plastic 30, and the top cover 10 can be located between the top cover 10 and the lower plastic 30, and outside the column 41. In the Z direction, the projection of the base 42 on the lower plastic 30 can partially fall into the lower plastic 30. In other words, in the Z direction, there can be a certain overlap between the base 42 and the lower plastic 30.

[0082] Partial base 42 can be located within the receiving groove 33, the limiting groove 15, and the second hole 31 of the lower plastic 30. The base 42 can contact or have a gap with the bottom wall of the receiving groove 33 of the lower plastic 30. It is understood that by partially positioning the base 42 within the lower plastic 30, the structure of the lower plastic 30 can be leveraged to provide a certain degree of positional restraint for the terminal 40, thereby enhancing the installation stability of the terminal 40. When the base 42 contacts the bottom wall of the receiving groove 33 of the lower plastic 30, the base 42 and the lower plastic 30 can have a larger contact area, which helps enhance the stability and reliability of the connection between the terminal 40 and the lower plastic 30. When there is a gap between the base 42 and the bottom wall of the receiving groove 33 of the lower plastic 30, this gap can be used to provide sufficient space for the sealing ring 50 to deform, preventing the sealing ring 50 from losing its elasticity due to the lack of space, which in turn causes sealing failure.

[0083] Please refer to Figure 10 、 Figure 12 and Figure 13 , Figure 12 yes Figure 3 The structural diagram of the sealing ring 50 of the top cover assembly 100 is shown at an angle. Figure 13 yes Figure 3 The structure diagram of the sealing ring 50 of the top cover assembly 100 is shown from another angle.

[0084] The sealing ring 50 can have excellent elastic deformation properties, allowing it to elastically deform when under pressure and rebound when the pressure is removed. The sealing ring 50 can have a first state and a second state. When the sealing ring 50 is in the first state, the sealing ring 50 is separated from both the lower plastic 30 and the top cover 10. When the sealing ring 50 is in the second state, the sealing ring 50 is sleeved on the outside of the column 41 of the pole 40 and located within the first hole 13 of the top cover 10, the second hole 31 of the lower plastic 30, and the groove 32 of the lower plastic 30. In other words, when the sealing ring 50 is in the first state, the sealing ring 50 is in a natural state without pressure. When the sealing ring 50 is in the second state, the sealing ring 50 is in a compressed state under pressure. The following description will use the sealing ring 50 in the second state as an example, but it should be understood that this is not a limitation.

[0085] Please continue reading Figure 10 、 Figure 12 and Figure 13 The sealing ring 50 can be sleeved on the outside of the column 41 of the pole 40. One end of the sealing ring 50 can contact the upper plastic 20, and the other end of the sealing ring 50 (i.e., the end of the sealing ring 50 away from the upper plastic 20) can abut against the base 42 of the pole 40.

[0086] Optionally, the height of the first sub-pillar 411 of the pole 40 may be a first height H1. The height of the upper plastic 20 between the pressing block 60 and the base 42 may be a second height H2. The height of the sealing ring 50 between the pressing block 60 and the base 42 may be a third height H3. The first height H1, the second height H2, and the third height H3 may satisfy the relationship: H1 < H2 + H3.

[0087] As a result, the sealing ring 50 and the upper plastic 20 can be interference-fitted in the Z direction, thereby eliminating the gap between the upper plastic 20 and the sealing ring 50 and blocking the electrolyte flow channel between the top cover 10 and the pole 40, which is beneficial to sealing the gap between the top cover and the pole 40, so that the top cover assembly as a whole has good sealing performance.

[0088] Optionally, the protrusion height of the terminal 40 relative to the surface of the pressing block 60 facing away from the upper plastic 20 may be a fourth height H4 (H4 is not shown in the figure because the terminal 40 and the surface of the pressing block 60 facing away from the upper plastic 20 are flush). The height of the sealing ring 50 between the top cover 10 and the base may be a fifth height H5. The fourth height H4 may be less than or equal to the fifth height H5.

[0089] Therefore, during the assembly process of the top cover assembly 100, even if the sealing ring 50 is not assembled, the terminal 40 riveted to the pressing block 60 can still be protruded relative to the surface of the pressing block 60 away from the upper plastic 20, thereby preventing the electrolyte from flowing out of the top cover 10 and improving the working reliability of the battery 200.

[0090] In the embodiment of the present application, the sealing ring 50 can be located in the first hole 13 of the top cover 10, the second hole 31 of the lower plastic 30, and the groove 32 of the lower plastic 30. The sealing ring 50 located in the second hole 31 of the lower plastic 30 abuts against the first step structure T1, and the sealing ring 50 located in the groove 32 of the lower plastic 30 abuts against the second step structure T2.

[0091] It is understandable that in the related art, when the top cover assembly is assembled, the pole and the top cover have good insulation performance. However, when the top cover assembly comes into contact with the electrolyte, the electrolyte will invade the area where the pole of the top cover assembly is located. Due to errors such as the manufacturing tolerances of the components in the top cover assembly and the assembly tolerances during assembly, a gap will be formed between the radial direction of the sealing ring and the inner wall of the pole hole of the lower plastic. When there is electrolyte in this gap, it is easy to sharply reduce the insulation performance between the top cover and the pole, resulting in reduced safety of the electrode assembly. In addition, foreign matter such as metal chips or water vapor in the middle can easily invade this gap, causing the insulation between the pole and the top cover to be further reduced.

[0092] Therefore, in the embodiment of the present application, by making the sealing ring 50 located in the second hole 31 of the lower plastic 30 abut against the first step structure T1, and the sealing ring 50 located in the groove 32 of the lower plastic 30 abut against the second step structure T2, the sealing ring 50 can form multiple steps between the top cover 10, the lower plastic 30 and the pole 40, which not only avoids interference between burrs at the corners of the pole 40 and the corners of the lower plastic 30, but also increases the creepage distance. It also enables the sealing ring 50 to effectively seal the gap enclosed by the lower plastic 30, the sealing ring 50 and the top cover 10, blocking the flow path of the electrolyte entering the gap between the pole 40 and the top cover 10, avoiding the problem of the pole 40 and the top cover 10 being connected due to contact with the electrolyte, resulting in a short circuit, and is conducive to improving the sealing performance and safety performance of the top cover assembly 100.

[0093] Please continue reading Figure 10 、 Figure 12 and Figure 13 The sealing ring 50 can contact the inner wall of the first hole 13 of the top cover 10, the inner wall of the second hole 31 of the lower plastic 30, the bottom wall of the groove 32 of the lower plastic 30, the sidewalls of the groove 32 of the lower plastic 30, and a portion of the second surface 12 of the top cover 10. The sealing ring 50 located in the second hole 31 of the lower plastic 30 has an interference fit with the lower plastic 30 in the radial direction of the sealing ring 50. The sealing ring 50 located in the groove 32 of the lower plastic 30 has an interference fit with the top cover 10 in the radial direction of the sealing ring 50.

[0094] It can be understood that, on the basis of forming a primary seal between the sealing ring 50 and the second hole 31 of the lower plastic 30, a secondary seal is formed between the sealing ring 50 and the groove 32 of the lower plastic 30, which can enhance the sealing performance of the sealing ring 50 and further prevent the electrolyte in the electrode assembly 220 or water vapor outside the battery 200 from entering the gap between the top cover 10 and the terminal 40, thereby causing the problem of electrical conduction between the top cover 10 and the terminal 40.

[0095] In the embodiment of the present application, the sealing ring 50 located in the first hole 13 of the top cover 10 can contact the end of the extension portion 22 away from the upper plastic body 21. Furthermore, the sealing ring 50 located in the first hole 13 of the top cover 10 can have an interference fit with the end of the extension portion 22 away from the upper plastic body 21.

[0096] It can be understood that by making the sealing ring 50 and the upper plastic 20 have an interference fit, the sealing ring 50 can cooperate with the upper plastic 20 to isolate the top cover 10 and the pole 40, so that there is good insulation performance between the top cover 10 and the pole 40, effectively avoiding the problem of short circuit caused by electrical conduction between the top cover 10 and the pole 40, and having better reliability.

[0097] Please refer to Figure 10 、 Figure 12 and Figure 13 The sealing ring 50 may include a sealing ring body 51 , a first skirt 52 and a second skirt 53 .

[0098] The sealing ring body 51 is sleeved around the outer side of the column 41 of the terminal 40 and positioned within the first hole 13 of the top cover 10 and the second hole 31 of the lower plastic member 30. The sealing ring body 51 may have a gap or contact with the inner wall of the first hole 13 of the top cover 10. The sealing ring body 51 may contact the end of the extension away from the upper plastic member 21. Furthermore, the sealing ring body 51 may have an interference fit with the end of the extension away from the upper plastic member 21.

[0099] The first skirt 52 surrounds and connects to the outer edge of the sealing ring body 51 and is located within the second hole 31 of the lower plastic 30. The first skirt 52 can abut against the protrusion 35 of the lower plastic 30. Specifically, the first skirt 52 can abut against the first step structure T1. In the thickness direction of the sealing ring 50, the first skirt 52 is located between the top cover 10 and the base 42 of the terminal 40, and contacts both the fourth surface 342 of the top cover 10 and the surface of the terminal 40 facing the top cover 10.

[0100] The second skirt 53 surrounds and connects to the outer edge of the first skirt 52 and is located within the groove 32 of the lower plastic 30. The second skirt 53 can abut against the protrusion 35 of the lower plastic 30. Specifically, the second skirt 53 can abut against the second step structure T2. In the thickness direction of the sealing ring 50, the second skirt 53 is located between the lower plastic 30 and the base 42 of the terminal 40, and contacts both the bottom wall of the groove 32 of the lower plastic 30 and the surface of the terminal 40 facing the top cover 10.

[0101] The sealing ring body 51 can contact the end of the extension 22 away from the upper plastic body 21. The thickness G2 of the first skirt 52 can be less than the thickness G1 of the sealing ring body 51, thereby forming a first-level step structure at the connection between the sealing ring body 51 and the first skirt 52. The thickness G3 of the second skirt 53 can be less than the thickness G2 of the first skirt 52, thereby forming a second-level step structure at the connection between the first skirt 52 and the second skirt 53. Thus, the sealing ring 50 can form a two-level step structure.

[0102] It can be understood that by making the sealing ring 50 include a sealing ring body 51, a first skirt 52 and a second skirt 53 of different thicknesses, the two-step structure formed by the sealing ring 50 can be utilized when assembling the top cover assembly 100, so that the sealing ring 50 can be quickly and fully deformed between the lower plastic 30 and the pole 40, and between the top cover 10 and the pole 40, filling the spaces of different sizes between the lower plastic 30 and the pole 40, and between the top cover 10 and the pole 40, thereby improving the assembly efficiency and sealing performance of the top cover assembly 100.

[0103] The above is a detailed introduction to the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of the present application. At the same time, for those skilled in the art, according to the idea of the present application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A top cover assembly, characterized in that: The top cover assembly includes a top cover, a lower plastic, a pole and a sealing ring: The top cover is provided with a first hole, and the first hole penetrates the top cover along the thickness direction of the top cover; The lower plastic is stacked with the top cover, and the lower plastic is provided with a second hole and a groove. The second hole penetrates the lower plastic along the thickness direction of the lower plastic and is coaxially arranged and connected to the first hole. The inner wall of the second hole cooperates with the portion of the surface of the top cover facing the lower plastic to form a first step structure. The opening of the groove is located on the surface of the lower plastic facing away from the top cover. The groove is located on the periphery of the second hole and is connected to the second hole. The side walls of the groove cooperate with the bottom wall of the groove to form a second step structure. The pole is passed through the first hole and the second hole; The sealing ring is sleeved on the pole and located in the first hole, the second hole and the groove. The sealing ring located in the second hole abuts against the first step structure, and the sealing ring located in the groove abuts against the second step structure.

2. The top cover assembly according to claim 1, wherein: The sealing ring includes a sealing ring body, a first skirt and a second skirt. The sealing ring body is sleeved on the pole and is located in the first hole and the second hole. The first skirt is connected to the outer edge of the sealing ring body and is located in the second hole. The first skirt is abutted against the first step structure. The second skirt is connected to the outer edge of the first skirt and is located in the groove. The second skirt is abutted against the second step structure.

3. The top cover assembly according to claim 1 or 2, wherein: The top cover is further provided with a mounting groove, the opening of which is located on the surface of the top cover away from the lower plastic, and the mounting groove is located outside the first hole and communicates with the first hole; The top cover assembly also includes an upper plastic, which includes an upper plastic body and an extension portion that are connected to each other. The upper plastic body and the extension portion are both sleeved on the outside of the pole. Part of the upper plastic body is located in the mounting groove and the first hole. The extension portion is located in the first hole, and one end away from the upper plastic body is in contact with the sealing ring.

4. The top cover assembly according to claim 3, wherein: The top cover assembly further includes a pressing block, which is sleeved on the pole and connected to the pole, and at least a portion of the pressing block is embedded in the upper plastic; The pole includes a base, a first sub-column and a second sub-column, a portion of the base is surrounded by the lower plastic, and another portion of the base protrudes relative to the lower plastic in a direction away from the top cover, and the base also abuts against an end of the sealing ring away from the upper plastic. The first sub-column is coaxially arranged and connected to the base, the first sub-column is surrounded by the upper plastic and the sealing ring, and is located between the pressure block and the base, the second sub-column is coaxially arranged with the first sub-column, and is connected to an end of the first sub-column away from the base, and at least a portion of the second sub-column is surrounded by the pressure block.

5. The top cover assembly according to claim 4, wherein: The height of the first sub-column is a first height H1, the height of the upper plastic between the pressing block and the base is a second height H2, and the height of the sealing ring between the pressing block and the base is a third height H3; The first height H1, the second height H2 and the third height H3 satisfy the relationship: H3<H1+H2.

6. The top cover assembly according to claim 4 or 5, characterized in that: The protruding height of the pole relative to the surface of the pressing block away from the upper plastic is a fourth height H4, the height of the sealing ring between the top cover and the base is a fifth height H5, and the fourth height H4 is less than or equal to the fifth height H5.

7. The top cover assembly according to claim 2, wherein: The top cover is provided with a limiting groove, the opening of which is located on the surface of the top cover facing the lower plastic, the limiting groove is located outside the first hole and is in communication with the first hole; The lower plastic includes a lower plastic body and a convex portion. The lower plastic body is stacked with the top cover. The convex portion is connected to the surface of the lower plastic body facing the top cover. The convex portion and the lower plastic body are arranged to form the second hole and the groove. The convex portion is located in the limiting groove and abuts against both the first skirt and the second skirt.

8. The top cover assembly according to claim 7, wherein: The top surface of the protrusion contacts the bottom wall of the limiting groove, and the outer side surface of the protrusion contacts the side wall of the limiting groove.

9. The top cover assembly according to claim 8, wherein: An included angle between the bottom wall of the limiting groove and the side wall of the limiting groove is an obtuse angle.

10. The top cover assembly according to claim 7, wherein: The lower plastic is also provided with a receiving groove, the opening of which is located on the surface of the lower plastic facing away from the top cover. The receiving groove is provided on the periphery of the limiting groove and is connected to the limiting groove. Part of the pole is located in the receiving groove and abuts against the sealing ring.

11. The top cover assembly according to claim 10, wherein: The pole includes a column and a base, the column and the base are coaxially arranged and connected, part of the column is located in the first hole and the second hole, and part of the base is located in the accommodating groove, the limiting groove and the second hole, and the base is in contact with the bottom wall of the accommodating groove or has a gap.

12. A battery, characterized in that: The battery includes an electrode assembly, a shell and a top cover assembly according to any one of claims 1 to 11, wherein the top cover assembly is connected to the shell and is surrounded by the shell to form a receiving space, and the electrode assembly is located in the receiving space.

13. An energy storage device, characterized in that: The energy storage device comprises the battery as claimed in claim 12.

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