Top cover assembly, battery and electric equipment

Abstract

The invention provides a top cover assembly, a battery and electric equipment. Comprising lower plastic and a supporting piece. The lower plastic comprises a lower plastic body and a central boss which are connected, the lower plastic body comprises a first surface and a second surface, the central boss protrudes relative to the second surface, and the central boss comprises a bottom surface and a first side surface connected between the bottom surface and the second surface; the lower plastic is provided with a mounting groove and a plurality of first exhaust holes formed at intervals, the mounting groove is located in the lower plastic body and the center boss, the first exhaust holes are located in the first side face and the bottom face, and at least one first exhaust hole communicates with the mounting groove; the supporting piece is positioned in the mounting groove and is supported between the lower plastic and the top cover; the mounting groove comprises a first side wall, a first air channel is formed between the first side wall and the supporting piece, the first air channel is communicated with the at least one first exhaust hole, and the size of the first air channel in the length direction of the lower plastic is gradually reduced in the direction from an opening of the mounting groove to the bottom wall. According to the technical scheme, the problem of difficulty in exhausting during thermal runaway of the battery cell can be solved.

Description

Technical Field

[0001] This application relates to the technical field of energy storage, and particularly to a top cover assembly, a battery, and an electrical device. Background Art

[0002] With the development of clean energy, batteries with recyclable characteristics are becoming increasingly popular. A battery includes an electrode assembly, a housing, and a top cover assembly. The electrode assembly is located in a receiving space formed by enclosing the housing and the top cover assembly. The top cover assembly includes a top cover, a lower plastic, and an explosion-proof valve, and the top cover and the lower plastic are stacked. When the battery cell of the electrode assembly undergoes thermal runaway, the lower plastic is easily melted, causing the battery cell to float, blocking the exhaust passage at the top cover, and preventing the gas inside the battery cell from being effectively discharged, resulting in an explosion due to excessive internal pressure of the battery cell. Summary of the Invention

[0003] Embodiments of this application provide a top cover assembly, a battery, and an electrical device, which can solve the problem that the gas inside the battery cell cannot be effectively exhausted when the battery cell undergoes thermal runaway.

[0004] In a first aspect, this application provides a top cover assembly, and the top cover assembly includes a lower plastic and a support member; The top cover assembly includes a top cover, a lower plastic, and a support member; The lower plastic includes a lower plastic body and a central boss. The lower plastic body is stacked with the top cover. The lower plastic body includes a first surface and a second surface, and the first surface and the second surface face away from each other in the thickness direction of the lower plastic body. The central boss is connected to the lower plastic body and protrudes relative to the second surface. The central boss includes a bottom surface and a first side surface. The bottom surface is spaced from the second surface in the thickness direction of the lower plastic. The first side surface is connected between the second surface and the bottom surface, and the first side surface is one of the two side surfaces of the central boss spaced along the length direction of the lower plastic; The lower plastic is provided with a mounting groove and a plurality of first exhaust holes. The mounting groove is located in the lower plastic body and the central boss, and the opening of the mounting groove is located on the first surface. The plurality of first exhaust holes are spaced along the width direction of the lower plastic. Each first exhaust hole is located on the first side surface and the bottom surface, and penetrates the central boss along both the length direction and the thickness direction of the lower plastic. At least one of the plurality of first exhaust holes communicates with the mounting groove; The support member is located in the mounting groove. In the thickness direction of the top cover assembly, one side of the support member abuts against the bottom wall of the mounting groove, and the other side of the support member is used to support the top cover; The installation groove includes a first side wall, which is a side wall of the installation groove along the length direction of the lower plastic. A first air passage is formed between the first side wall and the support member. The first air passage communicates with at least one of the plurality of first exhaust holes. The dimension of the first air passage in the length direction of the lower plastic gradually decreases from the opening of the installation groove towards the bottom wall of the installation groove.

[0005] It can be understood that when the battery cell undergoes thermal runaway, the explosion-proof valve installed on the top cover is easily broken. The combustible gas and electric spark generated by the battery cell will be released to the air outside the battery through the explosion-proof valve, and then react under the action of oxygen in the air, causing the battery cell to catch fire. Since the temperature of the battery cell is relatively high during thermal runaway, the lower plastic is easily melted by the high temperature, resulting in difficulty for the lower plastic to play a blocking role when the battery cell floats under the action of the electrolyte and air pressure. As a result, the distance between the battery cell and the top cover becomes closer or even in contact, increasing the amount of combustible gas and electric spark splashing out of the battery, further increasing the possibility of contact between the combustible gas and electric spark and oxygen in the air, and exacerbating the risk of the battery cell catching fire.

[0006] Therefore, in the implementation of the present application, by providing a support member that is insulating and resistant to electrolyte corrosion between the lower plastic and the top cover, the top cover can be effectively supported, and the situation where the lower plastic undergoes high-temperature deformation during the early stage of thermal runaway of the battery cell and loses its binding effect on the battery cell can be improved. In addition, even if the lower plastic melts due to thermal runaway of the battery cell, the support member can support between the top cover and the battery cell, blocking the upward floating of the battery cell close to the top cover, thereby suppressing the phenomenon of electric spark splashing out of the explosion-proof valve and reducing the risk of the battery cell catching fire.

[0007] Moreover, by providing a plurality of first exhaust holes on the side surface of the central boss, the number of exhaust channels on the lower plastic can be increased, the exhaust rate of the gas inside the battery cell during thermal runaway of the battery cell can be improved, and thus the safety performance of the top cover assembly can be enhanced.

[0008] In addition, a first air passage is formed between the support member and the first side wall of the installation groove, and the first air passage communicates with at least one of the plurality of first exhaust holes. The first air passage can provide a passage for the gas entering the installation groove through the first exhaust hole, avoiding the problem of unsmooth exhaust and increased air pressure caused by the support member blocking the first exhaust hole of the central boss, which may lead to the explosion of the battery cell, and enabling the gas inside the battery cell to be effectively exhausted, improving the exhaust reliability of the gas.

[0009] In addition, by making the size of the first air passage in the length direction of the lower plastic gradually decrease from the opening of the installation groove towards the bottom wall of the installation groove, the distance between the support member and the first side wall of the installation groove can be designed to be narrower at the bottom and wider at the top. Among them, the narrower design at the bottom can reduce the swaying of the support member after it is installed in the lower plastic, and the wider design at the top can ensure that there is also a passage for exhaust gas in the area where the support member is located, improving the exhaust reliability of the lower plastic.

[0010] In a possible implementation manner, the support member includes a main body and a first fixing portion; The main body includes a first connection surface, which is a surface of the main body in the width direction of the lower plastic. The first connection surface includes a first sub-surface and two second sub-surfaces. The first sub-surface is connected between the two second sub-surfaces. In the thickness direction of the lower plastic, one second sub-surface, one first sub-surface, and the other second sub-surface are arranged in sequence; The first fixing portion is connected to one first sub-surface, and the first fixing portion and the two second sub-surfaces on the same side respectively enclose two first avoidance grooves. In the two first avoidance grooves, each first avoidance groove communicates with the first air passage.

[0011] In a possible implementation manner, the support member further includes a second fixing portion; The main body further includes a second connection surface, which is arranged opposite to the second connection surface in the width direction of the lower plastic. The second connection surface includes a third sub-surface and two fourth sub-surfaces. The third sub-surface is connected between the two fourth sub-surfaces. In the thickness direction of the lower plastic, one fourth sub-surface, one third sub-surface, and the other fourth sub-surface are arranged in sequence; The second fixing portion is connected to one third sub-surface, and the second fixing portion and the two fourth sub-surfaces on the same side respectively enclose two second avoidance grooves. In the two second avoidance grooves, each second avoidance groove communicates with the first air passage.

[0012] In a possible implementation manner, the main body further includes a first transition surface and a second transition surface. Both the first transition surface and the second transition surface are connected between the first connection surface and the second connection surface and are arranged opposite to each other in the length direction of the lower plastic; The connection between the first fixing portion and any one of the connections between the first transition surface and the second transition surface is a curved surface transition; and / or, The connection between the second fixing portion and any one of the connections between the first transition surface and the second transition surface is a curved surface transition.

[0013] In a possible implementation manner, the central boss further includes a second side surface, the second side surface is connected between the second surface and the bottom surface, and is spaced from the first side surface in the length direction of the lower plastic; The lower plastic is provided with a plurality of second exhaust holes, the plurality of second exhaust holes are spaced along the width direction of the lower plastic, each second exhaust hole is located on the second side surface and the bottom surface, and penetrates through the central boss along both the length direction and the thickness direction of the lower plastic, and at least one of the plurality of second exhaust holes communicates with the installation groove; The installation groove further includes a second side wall, the second side wall is oppositely arranged with the first side wall in the length direction of the lower plastic, a second air passage is formed between the second side wall and the support member, the second air passage communicates with at least one of the plurality of second exhaust holes, and the size of the second air passage in the length direction of the lower plastic gradually decreases from the opening of the installation groove to the bottom wall of the installation groove, and the second air passage communicates with each first avoidance groove and / or each second avoidance groove.

[0014] In a possible implementation manner, the installation groove further includes a third side wall and a fourth side wall, the third side wall and the fourth side wall are both connected between the first side wall and the second side wall, and the third side wall and the fourth side wall are oppositely arranged in the width direction of the lower plastic; A third air passage is formed between the third side wall and the support member, and the third air passage communicates with both the first air passage and the second air passage; and / or, A fourth air passage is formed between the fourth side wall and the support member, and the fourth air passage communicates with both the first air passage and the second air passage.

[0015] In a possible implementation manner, the lower plastic is provided with a cavity, the cavity is located between the lower plastic body and the central boss, and the opening of the cavity is located on the first surface. The lower plastic further includes a partition board, the partition board is connected to the bottom wall of the cavity and the two side walls of the cavity opposite to each other along the length direction of the lower plastic, and the partition board can cooperate with the inner wall of the cavity to partition out the installation groove in the cavity; A buckle is provided at one end of the partition board away from the bottom wall of the cavity, and at least part of the buckle is located in the first avoidance groove close to the top cover among the two first avoidance grooves, and the buckle is used to fix the support member.

[0016] In a possible implementation manner, the top cover is provided with an explosion-proof hole, the explosion-proof hole penetrates through the top cover along the thickness direction of the top cover, and the explosion-proof hole is used to connect with an explosion-proof valve; In the thickness direction of the top cover assembly, the projection of the support member on the top cover covers a part of the explosion-proof hole; or, In the thickness direction of the top cover assembly, the projection of the support member on the top cover is spaced apart from the explosion-proof hole.

[0017] In a possible implementation manner, the lower plastic also has a plurality of third exhaust holes, the plurality of third exhaust holes are spaced apart along the width direction of the lower plastic, and each of the third exhaust holes penetrates through the central boss along the thickness direction of the lower plastic, and at least one of the plurality of third exhaust holes communicates with the installation groove.

[0018] In a possible implementation manner, the lower plastic further includes a first edge boss, the first edge boss is connected to the lower plastic body and protrudes relative to the second surface, and the first edge boss is located at one end of the lower plastic body in the length direction; The first edge boss is provided with a plurality of fourth exhaust holes, the plurality of fourth exhaust holes are spaced apart along the width direction of the lower plastic and are arranged opposite to the plurality of first exhaust holes in the length direction of the lower plastic, and each of the fourth exhaust holes penetrates through the first edge boss along the length direction of the lower plastic.

[0019] In a possible implementation manner, the lower plastic further includes a second edge boss, the second edge boss is connected to the lower plastic body and protrudes relative to the second surface, and the second edge boss is located at the other end of the lower plastic body in the length direction; The second edge boss is provided with a plurality of fifth exhaust holes, the plurality of fifth exhaust holes are spaced apart along the width direction of the lower plastic and are arranged opposite to the plurality of second exhaust holes in the length direction of the lower plastic, and each of the fifth exhaust holes penetrates through the second edge boss along the length direction of the lower plastic.

[0020] In a possible implementation manner, the lower plastic is provided with a first hole group. In the length direction of the lower plastic, the first hole group is located on one side of the central boss and is adjacent to the central boss. The first hole group includes a sixth exhaust hole and a plurality of seventh exhaust holes. The sixth exhaust hole and the plurality of seventh exhaust holes both penetrate through the lower plastic along the thickness direction of the lower plastic. The plurality of seventh exhaust holes are sequentially sleeved outside the sixth exhaust hole in at least two first annular rings along the direction outward from the center line of the sixth exhaust hole in the width direction of the lower plastic. In the at least two first annular rings, the plurality of seventh exhaust holes located in the same first annular ring are spaced apart; In the thickness direction of the top cover assembly, the projection of the explosion-proof hole on the lower plastic body at least covers a part of the projection of the central boss on the lower plastic body and a part of the projection of the plurality of seventh exhaust holes on the lower plastic body.

[0021] In a possible implementation manner, the size of each of the first annular rings in the width direction of the lower plastic is greater than the size of each of the first annular rings in the length direction of the lower plastic, and the size of each of the first annular rings in the length direction of the lower plastic gradually increases first and then gradually decreases from one side in the width direction of the lower plastic to the other side in the width direction of the lower plastic.

[0022] In a possible implementation manner, the lower plastic further includes a convex portion, the convex portion is connected to both the lower plastic body and the central boss, and protrudes relative to the second surface. The sixth exhaust hole and the plurality of seventh exhaust holes are both provided in the convex portion and penetrate the convex portion in the thickness direction of the lower plastic; The lower plastic is further provided with a deflation groove, the opening of the deflation groove is located on the first surface, the deflation groove is recessed from the first surface towards the convex portion and the central boss, and the deflation groove is also communicated with the installation groove, the sixth exhaust hole, and the plurality of seventh exhaust holes. In the thickness direction of the top cover assembly, the projection of the deflation groove on the top cover can cover the explosion-proof hole.

[0023] In a second aspect, the present application further provides a battery, the battery includes an electrode assembly, a housing, and the top cover assembly as described above. The top cover assembly is connected to the housing and encloses a containing space with the housing, and the electrode assembly is located in the containing space.

[0024] In a third aspect, the present application further provides an electrical device, the electrical device includes the battery as described above. Description of the Drawings

[0025] Figure 1 is a schematic structural diagram of an energy storage system provided by an embodiment of the present application; Figure 2 is a schematic structural diagram of a battery provided by an embodiment of the present application; Figure 3 is a schematic structural diagram of a top cover assembly provided by an embodiment of the present application; Figure 4 is Figure 3 the exploded structural diagram of the top cover assembly shown; Figure 5 is Figure 3 a schematic structural diagram of a top cover of the top cover assembly shown at an angle; Figure 6 isFigure 3 A schematic structural diagram of the top cover of the top cover assembly shown in FIG. 1 from another angle; Figure 7 is along Figure 3 A schematic cross-sectional view of a partial structure obtained by cutting along the cutting line AA shown; Figure 8 yes Figure 3 A schematic structural diagram of the lower plastic of the top cover assembly at an angle shown; Figure 9 yes Figure 3 A schematic structural diagram of the lower plastic of the top cover assembly from another angle; Figure 10a yes Figure 8 A schematic diagram of a partial structure of the lower plastic at an angle shown; Figure 10b is along Figure 8 The schematic cross-sectional view of the partial structure of the lower plastic obtained by cutting along the cutting line BB shown; Figure 11 yes Figure 3 A schematic structural diagram of the lower plastic of the top cover assembly from another angle; Figure 12 is along Figure 3 A schematic cross-sectional view of a portion of the structure of the top cover assembly obtained by cutting along the cutting line CC shown; Figure 13 is along Figure 3 A schematic cross-sectional view of a portion of the structure of the top cover assembly obtained by cutting along the cutting line EE shown; Figure 14 yes Figure 3 A structural schematic diagram of a partial structure of the top cover assembly shown; Figure 15 yes Figure 3 A schematic structural diagram of an angle of a support member of a top cover assembly is shown.

[0026] Reference numerals: Energy storage system 400, power conversion device 410, first user load 420, second user load 430, electrical equipment 300, battery 200, top cover assembly 100, housing 210, electrode assembly 220, top cover 10, upper plastic 20, lower plastic 30, pole 40, connecting piece 51, sealing ring 52, pressing ring 53, limiting body 54, support member 60, heat insulation sheet 70, explosion-proof valve assembly 80, third surface 101, fourth surface 102, explosion-proof hole 11, installation table 12, groove 13, explosion-proof valve 81, explosion-proof valve protection sheet 82, lower plastic body 31, central boss 32, cavity 33, first surface 311, second surface 312, bottom surface 321, first side surface 322, second side surface 323, first exhaust hole 324, second exhaust hole 325, third exhaust hole 326, partition 34, buckle 341, guiding inclined surface 342, installation groove 35, first side wall 351, second side wall 352, third side wall 353, fourth side wall 354, first hole group 36, second hole group 37, sixth exhaust hole 361, seventh exhaust hole 362, first annular ring T1, eighth exhaust hole 371, ninth exhaust hole 372, second annular ring T2, convex portion 301, air leakage groove 302, first edge boss 38, second edge boss 39, fourth exhaust hole 381, fifth exhaust hole 391, first air passage S1, second air passage S2, third air passage S3, fourth air passage S4, main body 61, first fixing portion 62, second fixing portion 63, first support surface 611, second support surface 612, first connection surface 613, second connection surface 614, first transition surface 615, second transition surface 616, first sub-surface 6131, second sub-surface 6132, third sub-surface 6141, fourth sub-surface 6142, first avoidance groove 64, second avoidance groove 65. Detailed implementation manners

[0027] For the convenience of understanding, the terms involved in the embodiments of the present application are first explained.

[0028] And / or: It is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone.

[0029] Multiple: It means two or more than two.

[0030] Connection: It should be understood in a broad sense. For example, the connection between A and B can be that A is directly connected to B, or A is indirectly connected to B through an intermediate medium.

[0031] Next, the specific implementation manners of the present application will be clearly described in conjunction with the accompanying drawings.

[0032] The embodiments of the present application provide a top cover assembly, a battery, and an electrical equipment.

[0033] 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. As is well known, the current generation of green electric energy generally depends on photovoltaics, wind power, water potential, etc. However, problems such as strong intermittency and large volatility are common in wind energy and solar energy, which can cause grid instability, insufficient electricity during peak demand, and too much electricity during low demand. The unstable voltage can also damage the power. Therefore, the problem of "abandoning wind and light" may be caused by insufficient electricity demand or insufficient grid acceptance capacity. To solve these problems, energy storage is required. That is, the electric energy is converted into other forms of energy through physical or chemical means and stored, and the energy is converted back into electric energy and released when needed. Simply put, energy storage is similar to a large "portable power bank", which stores electric energy when photovoltaics and wind energy are sufficient and releases the stored electricity when needed.

[0034] Taking electrochemical energy storage as an example, an embodiment of the present application provides an electrical device. A set of chemical batteries are provided inside the electrical device, which mainly uses the chemical elements in the chemical batteries as the energy storage medium. The charge and discharge process is accompanied by chemical reactions or changes of the energy storage medium. Simply put, the electric energy generated by wind energy and solar energy is stored in the chemical batteries, and the stored electricity is released when the external electricity usage reaches the peak, or transferred to places with a shortage of electricity for further use.

[0035] Currently, the application scenarios of energy storage 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 corresponding types of electrical devices include: Large energy storage containers applied in the grid side energy storage scenario can serve as high-quality active and reactive power regulation power sources in the grid, realizing load matching of electric energy in time and space, enhancing the consumption capacity of renewable energy, and being of great significance in grid system standby, alleviating the power supply pressure during peak loads, and peak shaving and frequency modulation.

[0036] Small and medium-sized energy storage cabinets applied in the industrial and commercial energy storage scenario on the user side and household small energy storage boxes applied in the household energy storage scenario on the user side mainly operate in the mode of "peak shaving and valley filling". Since there is a large price difference in electricity bills at peak and valley positions according to electricity consumption demand, after users have electrical equipment, 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 electrical equipment is released for use to achieve the purpose of saving electricity bills. In addition, in remote areas and areas with high incidences of natural disasters such as earthquakes and hurricanes, the existence of household electrical equipment is equivalent to users providing a backup power source for themselves and the grid, eliminating the inconvenience caused by frequent power outages due to disasters or other reasons.

[0037] Please refer to Figure 1 , Figure 1 which is a schematic structural diagram of the energy storage system 400 provided by the embodiments of the present application. The embodiments of the present application are described by taking the household energy storage scenario in user-side energy storage as an example, and the electrical equipment 300 of the present application is not limited to the household energy storage scenario.

[0038] The embodiments of the present application provide an energy storage system 400, which includes an electric energy conversion device 410, a first user load 420, a second user load 430, and an electrical equipment 300. The electrical equipment 300 is a small energy storage box and can be installed on an outdoor wall in a wall-mounted manner. Specifically, the photovoltaic panel can convert solar energy into electric energy during the low electricity price period, and the electrical equipment 300 is used to store the electric energy and supply it to street lamps and household appliances for use during the high electricity price period, or supply power when the power grid is powered off / out of power.

[0039] Among them, the electrical equipment 300 may include, but is not limited to, single cells, battery modules, battery packs, battery systems, etc. When the electrical equipment 300 includes multiple batteries 200, the multiple batteries 200 are electrically connected and are all located inside the housing of the electrical equipment 300, and they can be protected by the housing from external environmental interference. Exemplarily, the multiple batteries 200 are arranged at intervals. The multiple batteries 200 can be connected in series, or in parallel, or in a series and parallel hybrid connection to achieve a larger capacity and power. The embodiments of the present application are described by taking the electrical equipment 300 including the battery 200 as an example, but it should be understood that the electrical equipment 300 is not limited thereto.

[0040] Optionally, the battery 200 can be a secondary battery, which refers to a battery monomer that can be activated by charging after the battery monomer discharges and can continue to be used. The battery 200 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., and the present application does not make specific limitations thereto.

[0041] Please refer to Figure 2 , Figure 2 which is a schematic structural diagram of a battery 200 provided by the embodiments of the present application.

[0042] For the convenience of description below, the length direction of the battery 200 is defined as the X direction, the width direction of the battery 200 is defined as the Y direction, and the height direction of the battery 200 is defined as the Z direction. The X direction, the Y direction, and the Z direction are perpendicular to each other in pairs.

[0043] The battery 200 may include a top cover assembly 100, a housing 210, and an electrode assembly 220. The top cover assembly 100 is connected to the housing 210, and together with the housing 210, they enclose a receiving space, and the electrode assembly 220 is located within the receiving space. Exemplarily, the top cover assembly 100 may be welded to the housing 210 by welding. The housing 210 may be made of a metallic material, such as aluminum alloy, etc. The battery 200 may be a cylindrical battery 200 or a square battery 200, etc.

[0044] Among them, the electrode assembly 220 may include at least two battery cells (not shown in the figure). The at least two battery cells are arranged in sequence along the thickness direction of the battery 200. The setting of multiple battery cells can increase the capacity of the battery 200, so that the battery 200 can be used for a long time, and further increase the applicable scenarios of the battery 200. Each battery cell may include a wound core, a first tab, and a second tab. Both the first tab and the second tab are connected to the wound core. The polarities of the first tab and the second tab are opposite, one is the positive tab and the other is the negative tab.

[0045] It should be noted that Figure 2 The purpose is only to schematically describe the connection relationship of the top cover assembly 100, the housing 210, and the electrode assembly 220, and does not specifically limit the connection positions, specific structures, and quantities of each component. The structure schematically shown in the embodiments 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 more or fewer components than Figure 2 shown, or combine certain components, or split certain components, or have different component arrangements. The components shown in the figure may be implemented in hardware, software, or a combination of software and hardware.

[0046] Please refer to Figure 3 and Figure 4 , Figure 3 which is a schematic structural diagram of the top cover assembly 100 provided by the embodiments of the present application, Figure 4 and Figure 3 is an exploded structural diagram of the top cover assembly 100 shown in

[0047] In this embodiment, the top cover assembly 100 may include a top cover 10, an upper plastic 20, a lower plastic 30, a terminal 40, a connecting piece 51, a sealing ring 52, a pressure ring 53, a limiting body 54, a support member 60, a heat insulating sheet 70, and an explosion-proof valve assembly 80.

[0048] The upper plastic 20 and the lower plastic 30 are both installed on the top cover 10. The upper plastic 20 is installed on one side of the top cover 10 in the thickness direction (the Z direction shown in the figure), and the lower plastic 30 is installed on the other side of the top cover 10 in the thickness direction. Moreover, the lower plastic 30 and the upper plastic 20 protrude from two opposite surfaces of the top cover 10 in the thickness direction respectively. Among them, the number of the upper plastics 20 can be two. The two upper plastics 20 are installed at intervals on both sides of the top cover 10 in the length direction (the X direction shown in the figure).

[0049] The terminal post 40 is installed on the top cover 10, the upper plastic 20 and the lower plastic 30, and is insulated from the top cover 10 through the upper plastic 20, the lower plastic 30 and the sealing ring 52. The terminal post 40 can also be used as the electrode lead-out of the battery 200 to realize the electrical connection between the battery 200 and external devices. Among them, the number of the terminal posts 40 can be two. The two terminal posts 40 can be the negative terminal post 40 and the positive terminal post 40 respectively. The two terminal posts 40 can be arranged at intervals in the length direction of the top cover 10. Each terminal post 40 is installed on the lower plastic 30, the top cover 10, one upper plastic 20 and one pressure ring 53.

[0050] The connecting piece 51 is located on the side of the lower plastic 30 facing away from the top cover 10, is connected to the terminal post 40, and is also welded to the tab of the electrode assembly 220 to realize the electrical connection between the terminal post 40 and the electrode assembly 220. Among them, the number of the connecting pieces 51 can be two. The two connecting pieces 51 can be the positive connecting piece 51 and the negative connecting piece 51 respectively. The two connecting pieces 51 can be arranged at intervals in the length direction (the X direction shown in the figure) of the lower plastic 30. Each connecting piece 51 is connected to one terminal post 40.

[0051] The sealing ring 52 is sleeved on the outside of the terminal post 40, and is located between the lower plastic 30 and the terminal post 40, and between the top cover 10 and the terminal post 40. The sealing ring 52 can be used to seal the gap between the top cover 10 and the terminal post 40 to prevent the electrolyte from invading here, which may cause the reduction of the insulation between the top cover 10 and the terminal post 40 and the safety of the electrode assembly 220. Among them, the number of the sealing rings 52 can be two. Among the two sealing rings 52, one sealing ring 52 is sleeved on the positive terminal post 40, and the other sealing ring 52 is sleeved on the negative terminal post 40.

[0052] The pressure ring 53 is installed on the upper plastic 20, is sleeved on the outside of the terminal post 40, and is electrically connected to the terminal post 40. Among them, the number of the pressure rings 53 can be two. The two pressure rings 53 are respectively installed on the two upper plastics 20 and are respectively electrically connected to the two terminal posts 40.

[0053] The limiting body 54 is inserted through the upper plastic 20 and is located between the pressure ring 53 and the top cover 10. Among them, the number of the limiting bodies 54 can be multiple. Multiple limiting bodies 54 are inserted through the two upper plastics 20 at intervals and are located between the top cover 10 and the two pressure rings 53. Exemplarily, the number of the limiting bodies 54 can be six. Among them, three limiting bodies 54 are inserted through one upper plastic 20 at intervals and are located between the top cover 10 and one pressure ring 53. The other three limiting bodies 54 are inserted through the other upper plastic 20 at intervals and are located between the top cover 10 and the other pressure ring 53.

[0054] The support member 60 is installed on the lower plastic 30 and is located between the lower plastic 30 and the top cover 10. The support member 60 abuts against the lower plastic 30 and can support the top cover 10. When the battery cell has a thermal runaway, the support member 60 can support between the battery cell and the top cover 10, keep a certain distance between the two, block the battery cell from floating up close to the top cover 10, thereby inhibiting the electric spark from splashing out of the explosion-proof valve 81 and reducing the risk of the battery cell catching fire.

[0055] The heat insulation sheet 70 is located between the lower plastic 30 and the connecting piece 51 to play a good heat insulation role. Among them, the number of the heat insulation sheets 70 can be four. Two of the heat insulation sheets 70 are located between the top cover 10 and one connecting piece 51, and the other two heat insulation sheets 70 are located between the top cover 10 and the other connecting piece 51.

[0056] The explosion-proof valve assembly 80 is installed on the top cover 10 and is used for the pressure relief protection of the battery 200.

[0057] The structures of the components in the top cover assembly 100 and the assembly relationship between the components will be described in detail below with reference to the drawings.

[0058] Please refer to Figure 5 and Figure 6 , Figure 5 which is Figure 3 a schematic structural diagram of the top cover 10 of the top cover assembly 100 shown in a certain angle, Figure 6 and Figure 3 is a schematic structural diagram of the top cover 10 of the top cover assembly 100 shown in another angle.

[0059] The top cover 10 may include a third surface 101 and a fourth surface 102. The fourth surface 102 and the third surface 101 are arranged back to back in the thickness direction (the illustrated Z direction) of the top cover 10. Among them, the third surface 101 may face away from the electrode assembly 220, and the fourth surface 102 may face the electrode assembly 220.

[0060] The top cover 10 may be provided with an explosion-proof hole 11. The explosion-proof hole 11 penetrates through the top cover 10 along the thickness direction of the top cover 10. Exemplarily, the explosion-proof hole 11 may be located at the center position of the top cover 10.

[0061] The top cover 10 may be provided with a mounting platform 12 and a groove 13. The mounting platform 12 may be provided on the third surface 101 and protrude in a direction away from the top cover 10 relative to the third surface 101. The mounting platform 12 may also be provided around the outer edge of the explosion-proof hole 11. The opening of the groove 13 may be located on the fourth surface 102. The groove 13 may be provided to be recessed from the fourth surface 102 toward the inside of the top cover 10. The groove 13 may be provided coaxially with and communicate with the explosion-proof hole 11.

[0062] See also Figure 7 , Figure 7 is along Figure 3 The cross-sectional schematic diagram of a partial structure obtained by cutting along the cutting line AA shown.

[0063] The explosion-proof valve assembly 80 may include an explosion-proof valve 81 and an explosion-proof valve protection sheet 82. The explosion-proof valve 81 and the explosion-proof valve protection sheet 82 may both be mounted on the top cover 10 and arranged sequentially in the thickness direction of the top cover 10. Specifically, the explosion-proof valve 81 may be located in the groove 13 of the top cover 10 and cover the opening of the explosion-proof hole 11 located on the fourth surface 102 of the top cover 10. The explosion-proof valve protection sheet 82 may be connected to the mounting platform 12 of the top cover 10 and cover the opening of the explosion-proof hole 11 located on the first surface 311 of the top cover 10. The explosion-proof valve protection sheet 82 may also cover the explosion-proof valve 81.

[0064] Please refer to Figure 8 and Figure 9 , Figure 8 yes Figure 3 The schematic diagram of the structure of the lower plastic 30 of the top cover assembly 100 at an angle is shown. Figure 9 yes Figure 3 The structure diagram of the lower plastic 30 of the top cover assembly 100 is shown in another angle. Figure 9 In the figure, the dotted arrow indicates the exhaust path.

[0065] The lower plastic 30 may be stacked with the top cover 10. The lower plastic 30 may include a lower plastic body 31 and a central boss 32. The lower plastic body 31 is located on one side of the thickness direction of the top cover 10 and is fixedly connected to the top cover 10 to achieve a fixed connection between the lower plastic 30 and the top cover 10. The central boss 32 may be fixedly connected to the lower plastic body 31 and protruded relative to the second surface 312 of the lower plastic body 31. The central boss 32 may be used to abut against the electrode assembly 220.

[0066] Specifically, the lower plastic body 31 may include a first surface 311 and a second surface 312. The second surface 312 may be disposed opposite to the first surface 311 in the thickness direction (Z direction in the figure) of the lower plastic 30. The first surface 311 may face the fourth surface 102 of the top cover 10, and the second surface 312 may face the electrode assembly 220.

[0067] The lower plastic 30 may be provided with a cavity 33. The cavity 33 may be located in the lower plastic body 31 and the central boss 32. The opening of the cavity 33 may be located on the first surface 311 of the lower plastic body 31. The cavity 33 may be recessed from the first surface 311 of the lower plastic body 31 into the interior of the lower plastic body 31 and the central boss 32. In the thickness direction of the lower plastic 30, the cavity 33 may extend from the lower plastic body 31 to the central boss 32. In the width direction of the lower plastic 30, the cavity 33 may extend from one side of the lower plastic 30 to the other side of the lower plastic 30.

[0068] The central boss 32 may be disposed opposite to the explosion-proof hole 11 of the top cover 10 in the Z direction. In the Z direction, the projection of the central boss on the top cover 10 may partially overlap with the explosion-proof hole 11 of the top cover 10. That is, a part of the central boss 32 may be covered by the projection of the explosion-proof hole 11 of the top cover 10 on the lower plastic 30 in the Z direction. The central boss 32 may include a bottom surface 321, a first side surface 322, and a second side surface 323. The bottom surface 321 may be spaced from the second surface 312 of the lower plastic body 31 in the thickness direction of the lower plastic 30. The first side surface 322 and the second side surface 323 may both be connected between the bottom surface 321 and the second surface 312 of the lower plastic body 31. The first side surface 322 and the second side surface 323 may be opposite and spaced from each other in the length direction (illustrated as the X direction) of the lower plastic 30.

[0069] The central boss 32 may be provided with a plurality of first exhaust holes 324 and a plurality of second exhaust holes 325. The plurality of first exhaust holes 324 may be spaced along the width direction (illustrated as the Y direction) of the lower plastic 30. The structures of the plurality of first exhaust holes 324 may be similar, the same, or different. Each first exhaust hole 324 is located on the first side surface 322 and the bottom surface 321, and penetrates the central boss 32 along both the length direction and the thickness direction (illustrated as the Z direction) of the lower plastic 30. Each first exhaust hole 324 may communicate with the cavity 33. That is, each first exhaust hole 324 is a through hole. A part of each first exhaust hole 324 is located on the first side surface 322, and the other part of each first exhaust hole 324 is located on the bottom surface 321. The plurality of second exhaust holes 325 may be spaced along the width direction of the lower plastic 30. The structures of the plurality of second exhaust holes 325 may be similar, the same, or different. Each second exhaust hole 325 is located on the second side surface 323 and the bottom surface 321, and penetrates the central boss 32 along both the length direction and the thickness direction of the lower plastic 30. Each second exhaust hole 325 may communicate with the cavity 33. That is, each second exhaust hole 325 is a through hole. A part of each second exhaust hole 325 is located on the second side surface 323, and the other part of each first exhaust hole 324 is located on the bottom surface 321.

[0070] Exemplarily, the number of the first exhaust holes 324 can be five. The five first exhaust holes 324 are spaced apart in the width direction of the lower plastic 30. The number of the second exhaust holes 325 can be five. The five second exhaust holes 325 are spaced apart in the width direction of the lower plastic 30.

[0071] It can be understood that by providing a plurality of first exhaust holes 324 and a plurality of second exhaust holes 325 on the side surface of the central boss 32, the number of exhaust channels on the lower plastic 30 can be increased, the exhaust rate of the gas inside the battery cell during thermal runaway of the battery cell can be improved, and thus the safety performance of the top cover assembly 100 can be improved.

[0072] The central boss 32 can be provided with a plurality of third exhaust holes 326. The structures of the plurality of third exhaust holes 326 can be similar, the same or different. The plurality of third exhaust holes 326 are spaced along the width direction of the lower plastic 30 on the bottom surface 321. Each third exhaust hole 326 penetrates the central boss 32 along the thickness direction of the lower plastic 30 and communicates with the cavity 33. That is, each third exhaust hole 326 is a through hole. Exemplarily, the number of the third exhaust holes 326 can be nine. The nine third exhaust holes 326 can be spaced apart in the thickness direction of the lower plastic 30. The nine third exhaust holes 326 can include three circular holes, two rectangular holes, two relatively small elliptical holes and two relatively large elliptical holes.

[0073] It can be understood that by providing a plurality of third exhaust holes 326 on the bottom surface 321 of the central boss 32, while ensuring the strength of the central boss 32, the number of exhaust channels on the lower plastic 30 can be increased as much as possible, so that there are more gas passages for the gas inside the battery cell, and the stress applied to the lower plastic 30 during thermal runaway of the battery cell can be dispersed, avoiding the problem of failure of the top cover assembly 100 caused by stress concentration, and the reliability is relatively strong.

[0074] Please continue to refer to Figure 8 and Figure 9 , the lower plastic 30 can further include a partition 34. Two ends of the partition 34 are respectively connected to two side walls of the cavity 33 opposite to each other along the length direction of the lower plastic 30. The partition 34 is also connected to the bottom wall of the cavity 33. A buckle 341 can be provided at one end of the partition 34 away from the bottom wall of the cavity 33. The partition 34 can cooperate with the inner wall of the cavity 33 to divide an installation groove 35 in the cavity 33. The installation groove 35 can be located in the lower plastic body 31 and the central boss 32. The opening of the installation groove 35 can be located on the first surface 311 of the lower plastic body 31. The installation groove 35 can communicate with at least one of the plurality of first exhaust holes 324, at least one of the plurality of third exhaust holes 326, and at least one of the plurality of second exhaust holes 325.

[0075] The number of the partitions 34 may be multiple. The structures of the multiple partitions 34 may be the same or different. The multiple partitions 34 may cooperate with the inner wall of the cavity 33 to separate multiple installation grooves 35 in the cavity 33. Exemplarily, the number of the partitions 34 may be two. The two partitions 34 may be respectively located on both sides of the width direction of the lower plastic 30 and spaced apart. The two partitions 34 may cooperate with the inner wall of the cavity 33 to separate two installation grooves 35 in the cavity 33. The two installation grooves 35 may be spaced apart in the width direction of the lower plastic 30.

[0076] Please refer to Figure 8 , Figure 10a and Figure 10b , Figure 10a yes Figure 8 The schematic diagram of the partial structure of the lower plastic 30 at an angle is shown. Figure 10b is along Figure 8 The cross-sectional view of a portion of the structure of the lower plastic 30 obtained by cutting along the cutting line BB is shown.

[0077] The mounting groove 35 may include a first side wall 351, a second side wall 352, a third side wall 353, and a fourth side wall 354. The first side wall 351 and the second side wall 352 may be arranged oppositely and spaced apart in the length direction (X direction in the figure) of the lower plastic 30. That is, the first side wall 351 and the second side wall 352 are two side walls of the mounting groove 35 that are arranged oppositely along the length direction of the lower plastic 30. The third side wall 353 and the fourth side wall 354 are both connected between the first side wall 351 and the second side wall 352. The fourth side wall 354 and the third side wall 353 are arranged oppositely and spaced apart in the width direction (Y direction in the figure) of the lower plastic 30. That is, the third side wall 353 and the fourth side wall 354 are two side walls of the mounting groove 35 that are arranged oppositely along the length direction of the lower plastic 30.

[0078] The first side wall 351 is disposed adjacent to the first side surface 322, and the second side wall 352 is disposed adjacent to the second side surface 323. The first side wall 351 and the second side wall 352 may both be inclined surfaces disposed obliquely to the bottom wall of the mounting groove 35. The extension directions of the first side wall 351 and the second side wall 352 may intersect. The distance between the first side wall 351 and the second side wall 352 along the length direction of the lower plastic 30 may gradually decrease from the first surface 311 of the lower plastic body 31 to the second surface 312.

[0079] Please refer to Figure 9 and Figure 11 , Figure 11 yes Figure 3 The structure diagram of the lower plastic 30 of the top cover assembly 100 is shown at another angle.

[0080] The lower plastic 30 may be provided with a first hole group 36 and a second hole group 37. In the length direction of the lower plastic 30, the first hole group 36 and the second hole group 37 are respectively located on both sides of the central boss 32 and are both adjacent to the central boss 32. Among them, the first hole group 36 and the second hole group 37 may be symmetrically arranged.

[0081] The first hole group 36 may include a sixth exhaust hole 361 and a plurality of seventh exhaust holes 362. The sixth exhaust hole 361 and the plurality of seventh exhaust holes 362 may both penetrate the lower plastic 30 along the thickness direction of the lower plastic 30. The sixth exhaust hole 361 may be located at the central position of the first hole group 36. The structures of the plurality of seventh exhaust holes 362 may be similar, the same or different. The plurality of seventh exhaust holes 362 may be sequentially sleeved outside the sixth exhaust hole 361 in at least two first annular rings T1 along the direction outward from the center line O1 of the lower plastic 30 in the width direction of the sixth exhaust hole 361. Among the at least two first annular rings T1, the plurality of seventh exhaust holes 362 located in the same first annular ring T1 are spaced apart, and the plurality of seventh exhaust holes 362 located in different first annular rings T1 are also spaced apart. Among them, in the Z direction, the projection of the explosion-proof hole 11 of the top cover 10 on the lower plastic body 31 at least covers part of the projection of the central boss 32 on the lower plastic body 31 and part of the projection of the plurality of seventh exhaust holes on the lower plastic body 31. That is, the projection of the explosion-proof hole 11 of the top cover 10 on the lower plastic 30 in the Z direction at least covers part of the central boss 32 and part of the plurality of seventh exhaust holes 362.

[0082] Exemplarily, the shape of the sixth exhaust hole 361 may be circular. The shape of the seventh exhaust hole 362 may be oval. The number of the sixth exhaust holes 361 may be one. The number of the seventh exhaust holes 362 may be eighteen. The eighteen seventh exhaust holes 362 may be sequentially sleeved outside the sixth exhaust hole 361 in two first annular rings T1 along the direction outward from the center line of the lower plastic 30 in the width direction of the sixth exhaust hole 361. One first annular ring T1 located inside has six seventh exhaust holes 362, and the other first annular ring T1 located outside has twelve seventh exhaust holes 362.

[0083] It can be understood that by making the projection of the explosion-proof hole 11 on the lower plastic 30 in the Z direction cover at least part of the central boss 32 and part of the plurality of seventh exhaust holes 362, the first hole group 36 can be an exhaust structure arranged around the explosion-proof hole 11. Such a setting can make the first hole group 36 and the explosion-proof hole 11 arranged opposite to each other in the Z direction, so that when the battery core has a thermal runaway, the internal gas of the battery core can pass through the first hole group 36 and directly discharge from the explosion-proof valve 81, shortening the exhaust path of the internal gas of the battery core, and avoiding the problem that the internal gas of the battery core cannot effectively exhaust through the explosion-proof valve 81 due to the blockage of the exhaust channel at the top cover 10, resulting in an excessive internal pressure of the battery core and causing an explosion, effectively improving the safety performance of the top cover assembly 100.

[0084] By arranging the sixth exhaust hole 361 at the central position in the first hole group 36 and arranging the plurality of seventh exhaust holes 362 outside the sixth exhaust hole 361 and nesting them in at least two first annular rings T1, on the basis of ensuring that the total volume of the exhaust channels in the lower plastic 30 is not reduced, the exhaust hole diameter of the lower plastic 30 around the explosion-proof valve 81 can be reduced, preventing the problem that the tab of the battery core contacts the top cover 10 through the exhaust hole and causes a short circuit, making the exhaust holes in the first hole group 36 present a relatively compact structural arrangement, increasing the arrangement density of the exhaust holes in the first hole group 36, and improving the exhaust reliability of the lower plastic 30.

[0085] Please continue to refer to Figure 9 and Figure 11 , for each first annular ring T1, the dimension D1 along the width direction of the lower plastic 30 is greater than the dimension D2 along the length direction of the lower plastic 30. And for each first annular ring T1, the dimension D2 along the length direction of the lower plastic 30 first gradually increases and then gradually decreases from one side in the width direction of the lower plastic 30 to the other side in the width direction of the lower plastic 30. Exemplarily, the shape of the first annular ring T1 can be triangular.

[0086] It can be understood that by making the dimension D1 of each first annular ring T1 along the width direction of the lower plastic 30 greater than the dimension D2 of each first annular ring T1 along the length direction of the lower plastic 30, more seventh exhaust holes 362 in the same first annular ring T1 can be arranged at the position close to the explosion-proof hole 11 of the top cover 10, so as to effectively shorten the gas flow path and make the gas pass through more quickly and conveniently. In addition, by making the dimension D2 of each first annular ring T1 along the length direction of the lower plastic 30 first gradually increase and then gradually decrease from one side in the width direction of the lower plastic 30 to the other side in the width direction of the lower plastic 30, each first annular ring T1 can be arranged in a triangular shape, which is beneficial to the small aperture and high-density arrangement of each exhaust hole.

[0087] The second hole group 37 may include an eighth exhaust hole 371 and a plurality of ninth exhaust holes 372. The eighth exhaust hole 371 and the plurality of ninth exhaust holes 372 may both penetrate the lower plastic 30 along the thickness direction of the lower plastic 30. The eighth exhaust hole 371 may be located at the central position of the second hole group 37. The structures of the plurality of ninth exhaust holes 372 may be similar, the same, or different. The plurality of ninth exhaust holes 372 may be sequentially and spacedly sleeved outside the eighth exhaust hole 371 in at least two second annular rings T2 along the direction outward from the center line O2 of the eighth exhaust hole 371 in the width direction of the lower plastic 30. Among the at least two second annular rings T2, the plurality of ninth exhaust holes 372 located in the same second annular ring T2 are spaced apart, and the plurality of ninth exhaust holes 372 located in different second annular rings T2 are also spaced apart. Wherein, in the Z direction, the projection of the explosion-proof hole 11 of the top cover 10 on the lower plastic body 31 at least covers part of the projection of the central boss 32 on the lower plastic body 31 and part of the projection of the plurality of ninth exhaust holes 372 on the lower plastic body 31. That is, the projection of the explosion-proof hole 11 of the top cover 10 on the lower plastic 30 in the Z direction at least covers part of the central boss 32 and part of the plurality of ninth exhaust holes 372.

[0088] Exemplarily, the shape of the eighth exhaust hole 371 may be circular. The shape of the ninth exhaust hole 372 may be oval. The number of the eighth exhaust holes 371 may be one. The number of the ninth exhaust holes 372 may be eighteen. The eighteen ninth exhaust holes 372 may be sequentially and spacedly sleeved outside the eighth exhaust hole 371 in two second annular rings T2 along the direction outward from the center line of the eighth exhaust hole 371 in the width direction of the lower plastic 30. One second annular ring T2 located inside has six ninth exhaust holes 372, and the other second annular ring T2 located outside has twelve ninth exhaust holes 372.

[0089] It can be understood that by making the projection of the explosion-proof hole 11 on the lower plastic 30 in the Z direction at least cover part of the central boss 32 and part of the plurality of ninth exhaust holes 372, the second hole group 37 can be an exhaust structure arranged around the explosion-proof hole 11. Such a setting can make the second hole group 37 and the explosion-proof hole 11 be oppositely arranged in the Z direction, so that when the battery cell has a thermal runaway, the internal gas of the battery cell can directly discharge from the explosion-proof valve 81 through the second hole group 37, shortening the exhaust path of the internal gas of the battery cell, and avoiding the problem that the internal gas of the battery cell cannot effectively exhaust through the explosion-proof valve 81 due to the blockage of the exhaust channel at the top cover 10, resulting in an excessive internal pressure of the battery cell and causing an explosion, effectively improving the safety performance of the top cover assembly 100.

[0090] By setting the eighth exhaust hole 371 at the central position in the second hole group 37 and arranging a plurality of ninth exhaust holes 372 outside the eighth exhaust hole 371 and nesting them in at least two second annular rings T2 layer by layer, on the basis of ensuring that the total volume of the exhaust passage in the lower plastic 30 is not reduced, the exhaust hole diameter of the lower plastic 30 around the explosion-proof valve 81 can be reduced, preventing the pole ear of the battery cell from contacting the top cover 10 through the exhaust hole and causing a short-circuit problem, making the exhaust holes in the second hole group 37 present a relatively compact structural arrangement, increasing the arrangement density of the exhaust holes in the second hole group 37, and improving the exhaust reliability of the lower plastic 30.

[0091] Please continue to refer to Figure 9 and Figure 11 , for each second annular ring T2, the dimension D3 in the width direction of the lower plastic 30 is greater than the dimension D4 in the length direction of the lower plastic 30. And for each second annular ring T2, the dimension D4 in the length direction of the lower plastic 30 first gradually increases and then gradually decreases from one side in the width direction of the lower plastic 30 to the other side in the width direction of the lower plastic 30. Exemplarily, the shape of the second annular ring T2 can be triangular.

[0092] It can be understood that by making the dimension D3 in the width direction of the lower plastic 30 for each second annular ring T2 greater than the dimension D4 in the length direction of the lower plastic 30 for each second annular ring T2, more ninth exhaust holes 372 in the same second annular ring T2 can be arranged at positions close to the explosion-proof hole 11 of the top cover 10, so that the flow path of the gas can be effectively shortened and the gas can pass through more quickly and conveniently. In addition, by making the dimension D4 in the length direction of the lower plastic 30 for each second annular ring T2 first gradually increase and then gradually decrease from one side in the width direction of the lower plastic 30 to the other side in the width direction of the lower plastic 30, each second annular ring T2 can be arranged in a triangular shape, which is conducive to the small hole diameter and high-density arrangement of each exhaust hole.

[0093] Please refer to in combination with Figure 8 and Figure 9 , the lower plastic 30 may further include a convex portion 301. The convex portion 301 may be located on both sides in the width direction (the illustrated X direction) of the central boss 32, and is connected to both the lower plastic body 31 and the central boss 32, and protrudes relative to the second surface 312 of the lower plastic body 31. Among them, the protruding height of the convex portion 301 relative to the second surface 312 of the lower plastic body 31 may be less than the protruding height of the central boss 32 relative to the second surface 312 of the lower plastic body 31. The sixth exhaust hole 361, a plurality of seventh exhaust holes 362, the eighth exhaust hole 371, and a plurality of ninth exhaust holes 372 are all provided in the convex portion 301 and penetrate the convex portion 301 in the thickness direction of the lower plastic 30.

[0094] The lower plastic 30 may also be provided with a venting groove 302. The venting groove 302 may be located in the lower plastic body 31 and the convex portion 301. The opening of the venting groove 302 is located on the first surface 311. The venting groove 302 may be recessed from the first surface 311 of the lower plastic body 31 in the direction of the convex portion 301 and the central boss 32. The venting groove 302 is also communicated with the cavity 33, the mounting groove 35, the sixth exhaust hole 361, a plurality of seventh exhaust holes 362, the eighth exhaust hole 371, and a plurality of ninth exhaust holes 372. In the thickness direction of the top cover assembly 100, the projection of the venting groove 302 on the top cover 10 may cover the explosion-proof hole 11. That is, in the Z-direction projection of the venting groove 302 on the top cover 10, it may cover the explosion-proof hole 11 of the top cover 10.

[0095] It can be understood that by recessing the venting groove 302 on the first surface 311 of the lower plastic 30, the space surrounded by the venting groove 302 can be utilized to leave a certain gap between the lower plastic 30 and the top cover 10, so that when the explosion-proof valve 81 installed in the explosion-proof hole 11 of the top cover 10 exhausts the battery cell, the air flow discharge amount around the explosion-proof hole 11 can be increased, the exhaust effect of the explosion-proof valve 81 can be improved, and the safety of the battery 200 can be ensured.

[0096] The lower plastic 30 may also include a first edge boss 38 and a second edge boss 39. Both the first edge boss 38 and the second edge boss 39 are connected to the lower plastic body 31 and protrude relative to the second surface 312 of the lower plastic body 31. The first edge boss 38 is located at one end of the lower plastic body 31 in the length direction, and the second edge boss 39 is located at the other end of the lower plastic body 31 in the length direction. The first edge boss 38 and the second edge boss 39 may both be used to abut against the electrode assembly 220.

[0097] The first edge boss 38 is provided with a plurality of fourth exhaust holes 381. The structures of the plurality of fourth exhaust holes 381 may be similar, the same, or different. The plurality of fourth exhaust holes 381 are spaced apart in the width direction of the lower plastic 30 and are relatively arranged in the length direction of the lower plastic 30 with the plurality of first exhaust holes 324. Each fourth exhaust hole 381 penetrates the first edge boss 38 along the length direction of the lower plastic 30. Exemplarily, the number of the fourth exhaust holes 381 may be four.

[0098] The second edge boss 39 is provided with a plurality of fifth exhaust holes 391. The structures of the plurality of fifth exhaust holes 391 may be similar, the same, or different. The plurality of fifth exhaust holes 391 are spaced apart in the width direction of the lower plastic 30 and are relatively arranged in the length direction of the lower plastic 30 with the plurality of second exhaust holes 325. Each fifth exhaust hole 391 penetrates the second edge boss 39 along the length direction of the lower plastic 30. Exemplarily, the number of the fifth exhaust holes 391 may be four.

[0099] It is understandable that by providing a plurality of fourth exhaust holes 381 on the side of the first edge boss 38 and a plurality of fifth exhaust holes 391 on the side of the second edge boss 39, an exhaust path can be formed from both sides of the length direction of the lower plastic 30 to the central area of ​​the lower plastic 30, so that the gas on both sides of the length direction of the lower plastic 30 passes through the first edge boss 38 and the second edge boss 39 respectively and converges in the direction of the central boss 32, and then can be concentratedly discharged from the explosion-proof valve 81 of the explosion-proof hole 11 installed on the top cover 10 to the outside of the battery 200. The number of exhaust channels on the lower plastic 30 is effectively increased, and the exhaust rate of the gas inside the battery cell when the battery cell is thermally runaway is increased, thereby improving the safety performance of the top cover assembly 100.

[0100] Please refer to Figure 12 , Figure 12 is along Figure 3 The cross-sectional schematic diagram of the partial structure of the top cover assembly 100 obtained by cutting along the cutting line CC shown. The support member 60 can be located in the mounting groove 35 of the lower plastic 30. In the thickness direction of the top cover assembly 100, one side of the support member 60 abuts against the bottom wall of the mounting groove 35, and the other side of the support member 60 is used to support the top cover 10. Among them, the support member 60 can be made of an insulating material that is resistant to electrolyte corrosion. Exemplarily, the support member 60 can be located entirely in the mounting groove 35. The other side of the support member 60 can abut against the top cover 10 when the battery cell is in thermal runaway, and have a gap with the top cover 10 under normal working conditions. In the thickness direction of the lower plastic 30, the distance of the gap between the support member 60 and the opening of the mounting groove can be in the range of 0.1mm-0.2mm (including the end values ​​of 0.1mm and 0.2mm). The material of the support member 60 can be ceramic.

[0101] It is understandable that when the battery cell has thermal runaway, the explosion-proof valve 81 installed on the top cover 10 is easily broken, and the combustible gas and electric sparks generated by the battery cell will be released into the air outside the battery 200 through the explosion-proof valve 81, and then react under the action of oxygen in the air, causing the battery cell to catch fire. Since the temperature of the battery cell is high during thermal runaway, the lower plastic 30 is easily melted by high temperature, resulting in the lower plastic 30 being difficult to stop when the battery cell floats under the action of electrolyte and air pressure, thereby making the distance between the battery cell and the top cover 10 closer or even in contact, causing more combustible gas and electric sparks to splash out of the battery 200, further increasing the possibility of combustible gas and electric sparks contacting with oxygen in the air, and exacerbating the risk of battery cell fire.

[0102] Thus, in the implementation of the present application, by providing a support member 60 that is insulating and resistant to electrolyte corrosion between the lower plastic 30 and the top cover 10, the top cover 10 can be effectively supported, improving the situation where the lower plastic 30 undergoes high-temperature deformation during the early stage of the triggering of the thermal runaway of the battery cell, and losing its binding effect on the battery cell. In addition, even if the lower plastic 30 melts due to the thermal runaway of the battery cell, the support member 60 can support between the top cover 10 and the battery cell, blocking the battery cell from floating close to the top cover 10, thereby suppressing the phenomenon of electric sparks splashing out of the explosion-proof valve 81 and reducing the risk of the battery cell catching fire.

[0103] In an embodiment of the present application, the support member 60 can be fixed by the buckle 341 of the partition plate 34. It can be understood that by engaging the support member 60 with the buckle 341 of the partition plate 34, the fixed connection between the support member 60 and the lower plastic 30 can be achieved conveniently and quickly, thereby effectively restricting the movement of the support member 60 and reducing the risk of the support member 60 falling off the lower plastic 30, improving the retention stability and reliability of the support member 60.

[0104] Among them, the number of the support members 60 can be one or more. When the number of the support members 60 is multiple, the structures of the multiple support members 60 can be similar, the same, or different. The multiple support members 60 are distributed at intervals between the top cover 10 and the lower plastic 30. Each support member 60 is supported between the top cover 10 and the lower plastic 30.

[0105] Exemplarily, the number of the support members 60 can be two. In the Y direction, the two support members 60 can be respectively located on both sides of the explosion-proof hole 11 of the top cover 10. It can be understood that compared with providing one support member 60 between the lower plastic 30 and the top cover 10, providing two support members 60 between the lower plastic 30 and the top cover 10 and making the two support members 60 be respectively located on both sides of the explosion-proof hole 11 of the top cover 10 can more surely keep a certain distance between the lower plastic 30 and the top cover 10. And when the battery cell undergoes thermal runaway, the two support members 60 have a stronger supporting effect on the battery cell, and can more effectively suppress the electric sparks generated by the battery cell from reaching the outside of the battery 200 through the explosion-proof valve 81, preventing the phenomenon of the battery cell catching fire.

[0106] Hereinafter, the structure of one support member 60 will be taken as an example to describe the support member 60 in detail. Without conflict, the description of the structure of one support member 60 hereinafter can be applied to other support members 60.

[0107] In an embodiment of the present application, as Figure 12As shown, in the Z direction, the projection of the support member 60 on the top cover 10 covers part of the explosion-proof hole 11. That is, the projection of the support member 60 on the top cover 10 along the Z direction can cover part of the explosion-proof hole 11 of the top cover 10. Alternatively, in the Z direction, the projection of the support member 60 on the top cover 10 is spaced apart from the explosion-proof hole 11. That is, the projection of the support member 60 on the top cover 10 along the Z direction can be spaced apart from the explosion-proof hole 11 of the top cover 10.

[0108] It can be understood that by arranging the support member 60 close to the explosion-proof hole 11 of the top cover 10, it can be ensured that there is always an appropriate interval between the top cover 10 and the lower plastic 30 at the periphery of the explosion-proof hole 11, so that when the battery cell thermally runs away, the support member 60 can exert its supporting force at a closer distance to support the battery cell and prevent the battery cell from approaching the top cover 10, thereby improving reliability.

[0109] See also Figure 13 , Figure 13 is along Figure 3 The section line EE shown is a schematic cross-sectional view of a portion of the structure of the top cover assembly 100 .

[0110] A first air passage S1 is formed between the support member 60 and the first sidewall 351 of the mounting groove 35. The first air passage S1 may be a gap area between the support member 60 and the first sidewall 351 of the mounting groove 35. The first air passage S1 communicates with at least one of the plurality of first exhaust holes 324.

[0111] It can be understood that a first air passage S1 is formed between the support member 60 and the first side wall 351 of the mounting groove 35, and the first air passage S1 is connected to at least one of the plurality of first exhaust holes 324. The first air passage S1 can provide a passage for the gas entering the mounting groove 35 through the first exhaust hole 324, thereby avoiding the problem of poor exhaust and increased air pressure caused by the support member 60 blocking the first exhaust hole 324 of the central boss 32, thereby causing the battery cell to explode, and effectively exhaust the gas inside the battery cell, thereby improving the reliability of gas exhaust.

[0112] like Figure 13 As shown, the dimension H1 of the first air passage S1 in the length direction (X direction in the figure) of the lower plastic 30 gradually decreases from the opening of the mounting groove 35 to the bottom wall of the mounting groove 35. That is, the distance (H1 in the figure) between the support member 60 and the first side wall 351 of the mounting groove 35 can gradually decrease from the opening of the mounting groove 35 to the bottom wall of the mounting groove 35.

[0113] It can be understood that by designing the first side wall 351 of the installation groove 35 to be an inclined plane inclined relative to the bottom wall of the installation groove 35, and making the distance between the support member 60 and the first side wall 351 of the installation groove 35 (i.e., the dimension H1 of the first air passage S1 in the length direction of the lower plastic) gradually decrease from the opening of the installation groove 35 to the bottom wall of the installation groove 35. The distance between the support member 60 and the first side wall 351 can be designed to be narrower at the bottom and wider at the top. Among them, the narrower design at the bottom can reduce the shaking of the support member 60 after it is installed in the lower plastic 30, and the wider design at the top can ensure that there is also a passage for exhaust gas in the area where the support member 60 is located, improving the exhaust reliability of the lower plastic 30.

[0114] Please continue to refer to Figure 13 , a second air passage S2 is formed between the support member 60 and the second side wall 352 of the installation groove 35. The second air passage S2 can be the gap area between the support member 60 and the second side wall 352 of the installation groove 35. The second air passage S2 communicates with at least one of the plurality of second exhaust holes 325.

[0115] It can be understood that a second air passage S2 is formed between the support member 60 and the second side wall 352 of the installation groove 35, and the second air passage S2 communicates with at least one of the plurality of second exhaust holes 325. The second air passage S2 can provide a passage for the gas entering the installation groove 35 through the second exhaust hole 325, avoiding the problem of poor exhaust and increased air pressure caused by the support member 60 blocking the second exhaust hole 325 of the central boss 32, and further causing the explosion of the battery cell, and enabling the gas inside the battery cell to be effectively exhausted, improving the exhaust reliability of the gas.

[0116] As Figure 13 shown, the dimension H2 of the second air passage S2 in the length direction (the X direction shown in the figure) of the lower plastic 30 gradually decreases from the opening of the installation groove 35 to the bottom wall of the installation groove 35. That is, the distance (the dimension H2 shown in the figure) between the support member 60 and the second side wall 352 of the installation groove 35 can gradually decrease from the opening of the installation groove 35 to the bottom wall of the installation groove 35.

[0117] It can be understood that by designing the second side wall 352 of the installation groove 35 to be an inclined plane inclined relative to the bottom wall of the installation groove 35, and making the distance between the support member 60 and the second side wall 352 of the installation groove 35 (i.e., the dimension H2 of the second air passage S2 in the length direction of the lower plastic) gradually decrease from the opening of the installation groove 35 to the bottom wall of the installation groove 35. The distance between the support member 60 and the second side wall 352 can be designed to be narrower at the bottom and wider at the top. Among them, the narrower design at the bottom can reduce the shaking of the support member 60 after it is installed in the lower plastic 30, and the wider design at the top can ensure that there is also a passage for exhaust gas in the area where the support member 60 is located, improving the exhaust reliability of the lower plastic 30.

[0118] Please refer to Figure 14 , Figure 14 which Figure 3 is a schematic structural view of a partial structure of the top cover assembly 100 shown in the figure.

[0119] In an embodiment of the present application, a third air passage S3 may be formed between the support member 60 and the third side wall 353 of the mounting groove 35. The third air passage S3 may communicate with both the first air passage S1 and the second air passage S2. And / or, a fourth air passage S4 may be formed between the support member 60 and the fourth side wall 354 of the mounting groove 35. The fourth air passage S4 communicates with both the first air passage S1 and the second air passage S2. Of course, in some other embodiments, the support member 60 may also abut against the third side wall 353 and / or the fourth side wall 354 of the mounting groove 35, and no strict limitation is imposed thereon.

[0120] It can be understood that by forming the third air passage S3 and / or the fourth air passage S4 between the support member 60 and the side wall of the mounting groove 35. On the one hand, it is possible to further avoid the problem of poor exhaust and increased air pressure caused by the support member 60 blocking the first exhaust hole 324 and / or the second exhaust hole 325 of the central boss 32, and further prevent the problem of the battery cell explosion. On the other hand, for each additional air passage left between the support member 60 and the side wall of the mounting groove 35, a channel for gas flow in the mounting groove 35 can be increased, thereby effectively improving the exhaust efficiency and exhaust reliability of the gas.

[0121] Please refer to in combination Figure 13 , Figure 14 and Figure 15 , Figure 15 which Figure 3 is a schematic structural view of one angle of the support member 60 of the top cover assembly 100 shown in the figure.

[0122] The support member 60 may include a main body 61, a first fixing portion 62, and a second fixing portion 63. The main body 61 may include a first support surface 611, a second support surface 612, a first connection surface 613, a second connection surface 614, a first transition surface 615, and a second transition surface 616. The first support surface 611 and the second support surface 612 may face away from each other and be spaced apart in the thickness direction (the illustrated Z direction) of the support member 60. The first support surface 611 may contact the bottom wall of the mounting groove 35, and the second support surface 612 may be used to support the top cover 10. Both the first connection surface 613 and the second connection surface 614 are connected between the first support surface 611 and the second support surface 612. The second connection surface 614 may be opposite to and spaced apart from the first connection surface 613 in the width direction (the illustrated Y direction) of the lower plastic 30. Both the first transition surface 615 and the second transition surface 616 are connected between the first support surface 611 and the second support surface 612, and are also connected between the first connection surface 613 and the second connection surface 614. The first transition surface 615 and the second transition surface 616 may be opposite to and spaced apart from each other in the length direction (the illustrated Y direction) of the lower plastic 30.

[0123] The first connection surface 613 may include a first sub-surface 6131 and two second sub-surfaces 6132. One first sub-surface 6131 is connected between the two second sub-surfaces 6132. In the thickness direction (the illustrated Z direction) of the lower plastic 30, one second sub-surface 6132, one first sub-surface 6131, and the other second sub-surface 6132 are arranged in sequence. That is, the two second sub-surfaces 6132 are respectively connected to opposite sides of one first sub-surface 6131 along the thickness direction of the lower plastic 30. The first sub-surface 6131 may be arranged parallel to the thickness direction of the lower plastic 30. Both of the two second sub-surfaces 6132 may be arranged obliquely to the thickness direction of the lower plastic 30, and the extending directions of the two may intersect.

[0124] The second connection surface 614 may include a third sub-surface 6141 and two fourth sub-surfaces 6142. One third sub-surface 6141 is connected between the two fourth sub-surfaces 6142. In the thickness direction (the illustrated Z direction) of the lower plastic 30, one fourth sub-surface 6142, one third sub-surface 6141, and the other fourth sub-surface 6142 are arranged in sequence. That is, the two fourth sub-surfaces 6142 are respectively connected to opposite sides of one third sub-surface 6141 along the thickness direction of the lower plastic 30. The third sub-surface 6141 may be arranged parallel to the thickness direction of the lower plastic 30. Both of the two fourth sub-surfaces 6142 may be arranged obliquely to the thickness direction of the lower plastic 30, and the extending directions of the two may intersect.

[0125] The first fixing part 62 is connected to a first sub - surface 6131. The first fixing part 62 and two second sub - surfaces 6132 on the same side respectively enclose two first relief grooves 64. The second fixing part 63 is connected to a third sub - surface 6141. The second fixing part 63 and two fourth sub - surfaces 6142 on the same side respectively enclose a second relief groove 65. In the two first relief grooves 64, each first relief groove 64 is communicated with any one or a combination of the first air passage S1, the second air passage S2, the third air passage S3, and the fourth air passage S4. In the two second relief grooves 65, each second relief groove 65 is communicated with any one or a combination of the first air passage S1, the second air passage S2, the third air passage S3, and the fourth air passage S4. In the two first relief grooves 64, a first relief groove 64 close to the top cover 10 can accommodate at least part of the buckle 341 of the partition plate 34. Further, as Figure 12 shown, the surface of the buckle 341 facing the main body 61 can be a guiding inclined surface 342. The guiding inclined surface 342 can be inclined with respect to the thickness direction of the lower plastic 30. The guiding inclined surface 342 can improve the installation performance of the support member 60 and prevent the support member 60 from scratching the lower plastic 30.

[0126] Among them, the first transition surface 615 and the first side wall 351 of the installation groove 35 can form the first air passage S1 described above. The second transition surface 616 and the second side wall 352 of the installation groove 35 can form the second air passage S2 described above. The end surface of the first fixing part 62 away from the main body 61 can form the third air passage S3 with the third side wall 353 of the installation groove 35. The end surface of the second fixing part 63 away from the main body 61 can form the fourth air passage S4 with the fourth side wall 354 of the installation groove 35.

[0127] It can be understood that four relief grooves are respectively designed at the four sides of the support member 60. In addition to playing an anti - misalignment role during assembly, it can effectively prevent interference between the support member 60 and the buckle 341 of the partition plate 34, enabling an obvious functional distinction between the two parts of the support member 60 that play a supporting role and a fixing role, which is beneficial to improving the assembly efficiency of the support member 60 and the lower plastic 30. Moreover, on the basis that the support member 60 is fixed by the buckle 341 of the partition plate 34, the supporting surface of the support member 60 can be made as large as possible to better support the battery cell to prevent it from floating up after the lower plastic 30 melts, and ensure that the gas inside the battery cell can still be discharged through the explosion - proof valve 81.

[0128] In addition, each relief groove is communicated with any one or a combination of the first air passage S1, the second air passage S2, the third air passage S3, and the fourth air passage S4. This can increase the gas flow space in the installation groove 35, accelerate the exhaust rate, and improve the exhaust reliability.

[0129] In the embodiments of the present application, any connection between the first fixing portion 62 and the first connection surface 613 is a smooth arc transition R1. Any connection between the second fixing portion 63 and the second connection surface 614 is a smooth arc transition R2. Any connection between the first fixing portion 62 and the first transition surface 615, and any connection between the first fixing portion 62 and the second transition surface 616 are both arc transitions R3. Any connection between the second fixing portion 63 and the first transition surface 615, and any connection between the second fixing portion 63 and the second transition surface 616 are both arc transitions R4. Herein, the arc transition means that at the intersection of the surfaces of an object or between different regions, a circular arc or other arc-shaped structure is adopted to achieve a smooth transition design.

[0130] It can be understood that by designing any connection between each fixing portion and each connection surface and any connection between each fixing portion and each transition surface as an arc transition, the problem that the support member 60 scratches the lower plastic 30 during the use of the top cover assembly 100 can be effectively prevented, and the problems of the support member 60 generating chips or the lower plastic 30 generating wire drawing can be avoided, and the reliability is relatively good.

[0131] The embodiments of the present application have been introduced in detail above. Specific examples are used herein to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A top cover assembly, characterized in that, The top cover assembly includes a top cover, a lower plastic, and a support member; The lower plastic includes a lower plastic body and a central boss. The lower plastic body is stacked with the top cover. The lower plastic body includes a first surface and a second surface, and the first surface and the second surface face away from each other in the thickness direction of the lower plastic body. The central boss is connected to the lower plastic body and protrudes relative to the second surface. The central boss includes a bottom surface and a first side surface. The bottom surface is spaced from the second surface in the thickness direction of the lower plastic. The first side surface is connected between the second surface and the bottom surface, and the first side surface is one of the two side surfaces of the central boss spaced along the length direction of the lower plastic; The lower plastic is provided with a mounting groove and a plurality of first exhaust holes. The mounting groove is located in the lower plastic body and the central boss, and the opening of the mounting groove is located on the first surface. The plurality of first exhaust holes are spaced along the width direction of the lower plastic. Each first exhaust hole is located on the first side surface and the bottom surface, and penetrates through the central boss along both the length direction and the thickness direction of the lower plastic. At least one of the plurality of first exhaust holes communicates with the mounting groove; The support member is located in the mounting groove. In the thickness direction of the top cover assembly, one side of the support member abuts against the bottom wall of the mounting groove, and the other side of the support member is used to support the top cover; The mounting groove includes a first side wall. The first side wall is one side wall of the mounting groove along the length direction of the lower plastic. A first air passage is formed between the first side wall and the support member. The first air passage communicates with at least one of the plurality of first exhaust holes. The dimension of the first air passage in the length direction of the lower plastic gradually decreases from the opening of the mounting groove to the bottom wall of the mounting groove.

2. The top cover assembly according to claim 1, characterized in that, The support member includes a main body and a first fixing portion; The main body includes a first connecting surface. The first connecting surface is a surface of the main body in the width direction of the lower plastic. The first connecting surface includes a first sub-surface and two second sub-surfaces. The first sub-surface is connected between the two second sub-surfaces. In the thickness direction of the lower plastic, one second sub-surface, one first sub-surface, and the other second sub-surface are arranged in sequence; The first fixing portion is connected to one first sub-surface. The first fixing portion and the two second sub-surfaces on the same side respectively enclose two first avoidance grooves. In the two first avoidance grooves, each first avoidance groove communicates with the first air passage.

3. The top cover assembly according to claim 2, characterized in that, The support member further includes a second fixing portion; The main body further includes a second connecting surface. The second connecting surface is opposite to the first connecting surface in the width direction of the lower plastic. The second connecting surface includes a third sub-surface and two fourth sub-surfaces. The third sub-surface is connected between the two fourth sub-surfaces. In the thickness direction of the lower plastic, one fourth sub-surface, one third sub-surface, and the other fourth sub-surface are arranged in sequence; The second fixing portion is connected to one of the third sub - surfaces, and two second avoiding grooves are respectively formed by enclosing the second fixing portion and two of the fourth sub - surfaces on the same side. In the two second avoiding grooves, each second avoiding groove communicates with the first air passage.

4. The top cover assembly according to claim 3, characterized in that, The main body further includes a first transition surface and a second transition surface. Both the first transition surface and the second transition surface are connected between the first connection surface and the second connection surface and are oppositely arranged in the length direction of the lower plastic. Any connection between the first fixing portion and the first transition surface, and any connection between the first fixing portion and the second transition surface is arc - surface transition; and / or Any connection between the second fixing portion and the first transition surface, and any connection between the second fixing portion and the second transition surface is arc - surface transition.

5. The top cover assembly according to claim 4, characterized in that, The central boss further includes a second side surface. The second side surface is connected between the second surface and the bottom surface and is spaced from the first side surface in the length direction of the lower plastic. The lower plastic is provided with a plurality of second exhaust holes. The plurality of second exhaust holes are spaced along the width direction of the lower plastic. Each second exhaust hole is located on the second side surface and the bottom surface and penetrates through the central boss along both the length direction and the thickness direction of the lower plastic. At least one of the plurality of second exhaust holes communicates with the installation groove. The installation groove further includes a second side wall. The second side wall is oppositely arranged with the first side wall in the length direction of the lower plastic. A second air passage is formed between the second side wall and the support member. The second air passage communicates with at least one of the plurality of second exhaust holes. The dimension of the second air passage in the length direction of the lower plastic gradually decreases from the opening of the installation groove to the bottom wall of the installation groove. The second air passage communicates with each first avoiding groove and / or each second avoiding groove.

6. The top cover assembly according to claim 5, wherein The installation groove further includes a third side wall and a fourth side wall. Both the third side wall and the fourth side wall are connected between the first side wall and the second side wall, and the fourth side wall and the third side wall are oppositely arranged in the width direction of the lower plastic. A third air passage is formed between the third side wall and the support member. The third air passage communicates with both the first air passage and the second air passage; and / or A fourth air passage is formed between the fourth side wall and the support member. The fourth air passage communicates with both the first air passage and the second air passage.

7. The top cover assembly according to any one of claims 2-6, characterized in that, The lower plastic is provided with a cavity. The cavity is located between the lower plastic body and the central boss, and the opening of the cavity is located on the first surface. The lower plastic further includes a partition. The partition is connected to the bottom wall of the cavity and two opposite side walls of the cavity along the length direction of the lower plastic. The partition can cooperate with the inner wall of the cavity to partition out the installation groove in the cavity. One end of the partition plate away from the bottom wall of the cavity is provided with a buckle, and at least part of the buckle is located in one of the two first avoidance grooves close to the top cover, and the buckle is used to fix the support member.

8. The top cover assembly according to any one of claims 1-6, characterized in that, The top cover is provided with an explosion-proof hole, and the explosion-proof hole penetrates through the top cover along the thickness direction of the top cover, and the explosion-proof hole is used to connect with an explosion-proof valve; In the thickness direction of the top cover assembly, the projection of the support member on the top cover covers part of the explosion-proof hole; or, In the thickness direction of the top cover assembly, the projection of the support member on the top cover is spaced from the explosion-proof hole.

9. The top cover assembly according to any one of claims 1-6, characterized in that, The lower plastic is further provided with a plurality of third exhaust holes, and the plurality of third exhaust holes are spaced along the width direction of the lower plastic, and each of the third exhaust holes penetrates through the central boss along the thickness direction of the lower plastic, and at least one of the plurality of third exhaust holes communicates with the installation groove.

10. The top cover assembly according to any one of claims 1-6, characterized in that, The lower plastic further includes a first edge boss, the first edge boss is connected to the lower plastic body and protrudes relative to the second surface, and the first edge boss is located at one end of the lower plastic body in the length direction; The first edge boss is provided with a plurality of fourth exhaust holes, the plurality of fourth exhaust holes are spaced along the width direction of the lower plastic and are arranged opposite to the plurality of first exhaust holes in the length direction of the lower plastic, and each of the fourth exhaust holes penetrates through the first edge boss along the length direction of the lower plastic.

11. The top cover assembly according to claim 5, characterized in that, The lower plastic further includes a second edge boss, the second edge boss is connected to the lower plastic body and protrudes relative to the second surface, and the second edge boss is located at the other end of the lower plastic body in the length direction; The second edge boss is provided with a plurality of fifth exhaust holes, the plurality of fifth exhaust holes are spaced along the width direction of the lower plastic and are arranged opposite to the plurality of second exhaust holes in the length direction of the lower plastic, and each of the fifth exhaust holes penetrates through the second edge boss along the length direction of the lower plastic.

12. The top cover assembly according to claim 8, wherein The lower plastic is provided with a first hole group, in the length direction of the lower plastic, the first hole group is located on one side of the central boss and is adjacent to the central boss, the first hole group includes a sixth exhaust hole and a plurality of seventh exhaust holes, both the sixth exhaust hole and the plurality of seventh exhaust holes penetrate through the lower plastic along the thickness direction of the lower plastic, the plurality of seventh exhaust holes are arranged in at least two first annular rings in the direction outward from the center line of the width direction of the lower plastic of the sixth exhaust hole and are sequentially sleeved outside the sixth exhaust hole at intervals, and in the at least two first annular rings, the plurality of seventh exhaust holes in the same first annular ring are spaced apart; In the thickness direction of the top cover assembly, the projection of the explosion-proof hole on the lower plastic body covers at least part of the projection of the central boss on the lower plastic body and part of the projection of the plurality of seventh exhaust holes on the lower plastic body.

13. The top cover assembly according to claim 12, characterized in that, The dimension of each of the first annular rings in the width direction of the lower plastic is greater than the dimension of each of the first annular rings in the length direction of the lower plastic, and the dimension of each of the first annular rings in the length direction of the lower plastic gradually increases first and then gradually decreases from one side in the width direction of the lower plastic to the other side in the width direction of the lower plastic.

14. The top cover assembly according to claim 12 or 13, characterized in that, The lower plastic further includes a convex portion, the convex portion is connected to both the lower plastic body and the central boss, and protrudes relative to the second surface, the sixth exhaust hole and the plurality of seventh exhaust holes are both provided in the convex portion, and penetrate the convex portion in the thickness direction of the lower plastic; The lower plastic is further provided with a deflation groove, the opening of the deflation groove is located on the first surface, the deflation groove is recessed from the first surface towards the convex portion and the central boss, the deflation groove is also communicated with the installation groove, the sixth exhaust hole, and the plurality of seventh exhaust holes, and in the thickness direction of the top cover assembly, the projection of the deflation groove on the top cover can cover the explosion-proof hole.

15. A battery, characterized in that, The battery includes an electrode assembly, a housing, and the top cover assembly according to any one of claims 1-14, the top cover assembly is connected to the housing, and encloses a containing space with the housing, and the electrode assembly is located in the containing space.

16. An electrical device, characterized in that, The electrical device includes the battery according to claim 15.

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