Cover plate assembly, battery cell and electric device

Abstract

The application provides a cover plate assembly, a battery monomer and an electric device, relates to the technical field of batteries, and the cover plate assembly comprises a cover plate body and an explosion-proof valve. The cover plate body comprises a first surface and a second surface. The explosion-proof valve is arranged on the cover plate body and is in an integral molding structure with the cover plate body. The explosion-proof valve comprises an opening part and a buffer part. The buffer part is arranged around the periphery of the opening part. One end of the buffer part close to the first surface is connected with the cover plate body. The opening part is provided with a burst section and at least one reinforcing part. The burst section and the reinforcing part are arranged at intervals. The reinforcing part is in a convex structure protruding towards the first surface and / or the second surface. The burst section is arranged around the reinforcing part in the peripheral direction. In a plane perpendicular to the thickness direction of the cover plate body, the projected area of all the reinforcing parts is S1, and the projected area of the region surrounded by the burst section is S2. The following condition is met: 1% <= S1 / S2 <= 70%. Thus, the stability of the explosion-proof valve is ensured, and the yield of battery production is improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a cover plate assembly, a battery cell, and an electrical device. Background Technology

[0002] In related technologies, explosion-proof valves are typically fixed to the battery cover by welding. However, during the welding process, the heat generated often causes slight deformation of the explosion-proof valve, resulting in a reduction in the thickness of the grooves on the valve. This change directly affects the opening pressure of the explosion-proof valve. Secondly, the heat generated during welding of the battery casing and cover can also cause cracking of the explosion-proof valve, ultimately leading to complete malfunction. These problems not only significantly reduce the yield rate of battery production but also substantially increase production costs. Summary of the Invention

[0003] The purpose of this application is to provide a cover plate assembly, a battery cell, and an electrical device to solve the problem of poor stability of the explosion-proof valve in the battery cell of the prior art.

[0004] To achieve the above objectives, the technical solution adopted in this application is as follows: In a first aspect, this application provides a cover plate assembly, comprising: a cover plate body and an explosion-proof valve. The cover plate body includes a first surface and a second surface, which are disposed opposite to each other along the thickness direction of the cover plate body. The explosion-proof valve is disposed on the cover plate body and is integrally formed with the cover plate body. The explosion-proof valve includes an opening portion and a buffer portion, wherein the buffer portion is arranged circumferentially around the opening portion, and one end of the buffer portion far from the first surface is connected to the cover plate body. The opening portion is provided with a bursting section and at least one reinforcing portion, which are spaced apart. The reinforcing portion has a protruding structure protruding towards the first surface and / or the second surface. The bursting section is arranged circumferentially around all the reinforcing portions. On a plane perpendicular to the thickness direction of the cover plate body, the orthographic projection area of ​​all the reinforcing portions is S1, and the orthographic projection area of ​​the region enclosed by the inner edge of the bursting section near the center of the explosion-proof valve is S2; satisfying: 1%≤S1 / S2≤70%.

[0005] In one or more embodiments of this application, the reinforcing part has a hollow structure and protrudes toward the first surface or the second surface.

[0006] In one or more embodiments of this application, each reinforcement includes at least one protrusion structure disposed along its thickness direction.

[0007] In one or more embodiments of this application, it further includes: a pole post, which is disposed on the cover plate body, and at least a portion of the pole post protrudes from the first surface and forms a first electrical connection surface. Along the thickness direction of the cover plate body, the distance between the first electrical connection surface and the first surface is A2, the thickness of the cover plate body is A1, and the distance between the end of the explosion-proof valve away from the first surface and the first surface is A, satisfying: -0.5×A1≤A≤A2.

[0008] In one or more embodiments of this application, the buffer portion includes at least a first buffer section and a second buffer section. The first buffer section is connected to the cover plate body, and the second buffer section is connected to the opening portion. The second buffer section has a first wall surface, and the opening portion has a first opening surface connected to the first wall surface. The included angle between the first wall surface and the first opening surface is α, which satisfies: 90°≤α≤180°.

[0009] In one or more embodiments of this application, the buffer section further includes a bent section, a third buffer section, and a fourth buffer section; wherein the first buffer section, the third buffer section, the fourth buffer section, the bent section, and the second buffer section are connected sequentially from the cover plate body to the opening section; The first buffer section extends perpendicular to the thickness direction of the cover plate body. One end of the third buffer section is connected to the first buffer section, and the other end of the third buffer section extends along the thickness direction of the cover plate body. One end of the fourth buffer section is connected to the third buffer section, and the other end of the fourth buffer section is inclined away from the opening. One end of the second buffer section is connected to the fourth buffer section through a bending section, and the other end of the second buffer section is inclined towards the opening.

[0010] In one or more embodiments of this application, on a plane perpendicular to the thickness direction of the cover plate body, the orthographic projection area of ​​the region enclosed by the inner edge of the third buffer section near the center of the explosion-proof valve is S3, which satisfies: 70%≤S2 / S3≤95%.

[0011] In one or more embodiments of this application, on a plane perpendicular to the thickness direction of the cover plate body, the orthographic projection area of ​​the region enclosed by the outer edge of the third buffer section away from the center of the explosion-proof valve is S4, and the orthographic projection area of ​​the region enclosed by the outer edge of the first buffer section away from the center of the explosion-proof valve is S5, satisfying: 60%≤S4 / S5≤90%.

[0012] Secondly, this application provides a battery cell, comprising: a housing and a cover assembly as described in any of the first aspects, wherein the housing has an opening; and the cover assembly is connected to the opening of the housing.

[0013] Thirdly, this application provides an electrical device, comprising: an electrical main body and at least one battery cell as described in the second aspect, wherein the battery cell is electrically connected to the electrical main body.

[0014] Based on the above technical solutions, the cover plate assembly, battery cell, and power supply device of this application have at least the following beneficial technical effects: In the technical solution of this application embodiment, by making the explosion-proof valve and the cover plate body an integrally formed structure, the welding process between the explosion-proof valve and the cover plate body is eliminated. This eliminates the stress concentration and deformation caused by the welding connection between the explosion-proof valve and the cover plate body, thereby helping to maintain the wall thickness consistency of the bursting section and ensuring that the opening pressure of the explosion-proof valve is controlled within the design threshold. This avoids the risk of functional failure due to deformation of the explosion-proof valve caused by welding with the cover plate. At the same time, a buffer section is provided between the opening part and the cover plate body. The buffer section increases the heat conduction path length between the opening part and the cover plate body, thereby reducing the impact of welding heat and stress on the opening part of the explosion-proof valve, especially the bursting section. At least one reinforcing part is provided on the opening part to further increase the rigidity of the explosion-proof valve, thereby improving its resistance to deformation and reducing the deformation of the explosion-proof valve when heated or compressed, thus reducing the risk of cracking of the explosion-proof valve. Further adjustments are made to ensure that, on the plane perpendicular to the thickness direction of the cover plate, the projected area S1 of all reinforcing parts and the projected area S2 of the area enclosed by the inner edge of the bursting section near the center of the explosion-proof valve satisfy the following condition: 1% ≤ S1 / S2 ≤ 70%. If the ratio of S1 / S2 is less than 1%, the area proportion of the reinforcing parts is too small, and its reinforcing effect on the opening part is small; if the ratio of S1 / S2 is greater than 70%, the area proportion of the reinforcing parts is too large, which can easily affect the structure of the bursting section 200 during the stamping process, thus leading to an increase in the defect rate of the explosion-proof valve. Therefore, S1 and S2 need to be considered comprehensively to limit S1 / S2 to the range of 1% to 70%, which can ensure both the reinforcing effect on the opening part and the forming of the explosion-proof valve, thereby improving the yield rate of battery production. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the electrical device provided in the embodiments of this application.

[0017] Figure 2 This is a cross-sectional structural diagram of the battery pack in the electrical device provided in the embodiments of this application.

[0018] Figure 3 This is a schematic diagram of the structure of a single battery cell in a battery pack provided in an embodiment of this application.

[0019] Figure 4 This is a perspective view of the cover plate assembly in the battery cell provided in the embodiments of this application.

[0020] Figure 5 This is a partial cross-sectional view of the cover plate assembly provided in the embodiments of this application.

[0021] Figure 6 yes Figure 4 A magnified structural diagram at point E in the middle.

[0022] Figure 7 This is a cross-sectional view of the reinforcing portion in the cover plate assembly provided in the embodiments of this application.

[0023] Figure 8 This is a cross-sectional view of the reinforcement portion in a cover plate assembly provided in other embodiments of this application.

[0024] Figure 9 yes Figure 5 A magnified structural diagram at point E1.

[0025] Figure 10 This is a top view of the third buffer section in the cover plate assembly provided in the embodiments of this application.

[0026] Figure 11 This is a top view of a cover plate assembly provided in one embodiment of this application.

[0027] Figure 12 This is a top view of a cover plate assembly provided in another embodiment of this application.

[0028] In the diagram: 100-Electrical device; 110-Electrical main body; 111-Battery compartment; 120-Battery pack; 121-Battery cell; 122-Box; 1000-Cover assembly; 1001-Shell; 1-Cover body; 10-First surface; 11-Second surface; 2-Explosion-proof valve; 20-Opening section; 21-Buffer section; 22-Reinforcing section; 200-Explosion section; 201-First opening surface; 210-First buffer section; 211-Second buffer section; 212-Third buffer section; 213-Fourth buffer section; 214-Bending section; 215-Cavity; 220-First protrusion; 221-Second protrusion; 2120-Through hole; 2111-First wall surface; 3-Terminal post; 30-First electrical connection surface; 31-Second electrical connection surface. Detailed Implementation

[0029] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0030] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0031] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0033] In related technologies, explosion-proof valves are typically fixed to the battery cover by welding. However, the heat generated during the welding process often causes slight deformation of the explosion-proof valve, resulting in a reduction in the thickness of the grooves on the valve. This change directly affects the opening pressure of the explosion-proof valve. Secondly, the large amount of heat released during the welding of the battery casing and cover can also cause the explosion-proof valve to crack, ultimately leading to complete malfunction. These problems not only significantly reduce the yield rate of battery production but also substantially increase production costs.

[0034] To address the aforementioned issues, this application provides a cover plate assembly, a battery cell, and an electrical device to resolve the problem of poor stability of explosion-proof valves in the prior art.

[0035] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0036] Please see Figure 1 , Figure 1 This is a schematic diagram of an electrical device 100 provided in an embodiment of this application. Figure 1 In the illustrated embodiment, an electric vehicle is used as an example for illustrative purposes, and this should not be construed as a specific limitation of this application. In other embodiments, the electrical device may also be a mobile phone, laptop computer, mobile charging station, or other similar device.

[0037] Please see Figure 1 The power-consuming device 100 includes a power-consuming body 110 and a battery pack 120. The battery pack 120 is fixed to the power-consuming body 110 and electrically connected to the power-consuming components of the power-consuming body 110 to supply power to the power-consuming components of the power-consuming body 110. Specifically, the power-consuming body 110 may have a battery compartment 111, and the battery pack 120 is fixed inside the battery compartment 111. For example, the power-consuming components may be a drive motor, as well as various sensors (wheel speed sensors), etc.

[0038] Please continue reading. Figure 2 The battery pack 120 may include a housing 122 and at least one battery cell 121, wherein the battery cell 121 is electrically connected to the aforementioned power-consuming body 110. The battery cell 121 is fixed inside the housing 122, and the housing 122 can protect the battery cell 121 from external forces causing vibration and impact to damage the battery cell 121. The housing 122 may be a metal housing or a plastic housing.

[0039] The battery cell 121 is the most basic electrochemical unit, capable of storing and releasing electrical energy. The battery cell 121 can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and this application embodiment does not limit it. Figure 2 In the battery pack 120 shown, there are multiple battery cells 121. These multiple battery cells 121 can be electrically connected in series, in parallel, or in a mixed configuration. A mixed configuration means that the multiple battery cells 121 are connected in both series and parallel relationships, which can be specifically designed according to the power consumption requirements of the power-consuming device 100. In some other embodiments, the battery pack 120 may contain only one battery cell 121.

[0040] Please continue reading. Figure 3 The battery cell 121 may include a housing 1001, a battery cell, and a cover assembly 1000. The housing 1001 has a receiving cavity (not shown) and an opening (not shown) communicating with the receiving cavity. The receiving cavity is used to receive the battery cell and electrolyte. The opening is used to place the battery cell into the receiving cavity through the opening during battery cell assembly. The cover assembly 1000 is connected to the opening to close it, thereby forming a sealed battery cell structure. The battery cell has tabs that are electrically connected to the cover assembly 1000.

[0041] The housing 1001 can be a rigid component, and it can be generally rectangular in shape so that the battery cell 121 is also generally rectangular. The housing 1001 can be a metal housing. In some examples, the housing 1001 can be an aluminum alloy housing to make it lighter, which is beneficial for the lightweight of the battery cell and thus for the overall lightweight of the electrical device. In other examples, the housing 1001 can also be a stainless steel housing to give it higher strength, which in turn gives the battery cell 121 better overall strength and stronger resistance to puncture and vibration damage. In other embodiments, the housing 1001 can also be a flexible component. The battery pack 120 may be referred to as a battery in the following embodiments.

[0042] Please continue to refer to Figures 4-7 The cover assembly 1000 of this application includes a cover body 1 and an explosion-proof valve 2. The shape of the cover body 1 can be adapted to the shape of the housing 1001 with an opening. The cover body 1 is connected to the housing 1001 and seals the opening to protect the battery cell and prevent electrolyte leakage. Figure 4 In the illustrated embodiment, the cover plate body 1 is generally rectangular flat. In other embodiments, the cover plate body 1 may also be circular, triangular, or other shapes.

[0043] The cover body 1 can be a metal structural component, connected to the housing 1001 by welding, bonding, or snap-fitting. In some embodiments, the cover body 1 can be an aluminum alloy structural component, which is beneficial for the lightweighting of the battery cell 121 and the electrical device 100. In other examples, the cover body 1 can be a stainless steel component, so that the cover body 1 has high strength, thereby giving the battery cell 121 high strength.

[0044] The cover body 1 has a first surface 10 and a second surface 11. The first surface 10 and the second surface 11 are arranged opposite to each other along the thickness direction of the cover body 1. The first surface 10 can form part of the outer surface of the battery cell 121. The first surface 10 faces the outside of the housing 1001, and the second surface 11 faces the receiving cavity of the housing 1001.

[0045] The explosion-proof valve 2 is mounted on the cover plate body 1 and is integrally formed with the cover plate body 1. Compared with the prior art, which uses welding to connect the explosion-proof valve and the cover plate, this embodiment fundamentally eliminates the welding process required for the explosion-proof valve 2 and the cover plate body 1. This eliminates stress concentration and deformation of the explosion-proof valve 2 caused by the welding connection between the explosion-proof valve 2 and the cover plate body 1, and maintains the wall thickness consistency of the burst section 200. This ensures that the opening pressure of the explosion-proof valve 2 is controlled within the design threshold, avoiding the risk of failure due to welding deformation between the explosion-proof valve and the cover plate. In some embodiments, the outline shape of the explosion-proof valve 2 includes, but is not limited to, a circle or an oblong shape.

[0046] It should be noted that the integrated molding structure refers to a continuous and seamless integral structure formed by the explosion-proof valve 2 and the cover plate body 1 through the same manufacturing process, rather than an independent component assembled through subsequent connection processes such as welding or riveting.

[0047] The explosion-proof valve 2 includes an opening portion 20 and a buffer portion 21. The buffer portion 21 is arranged circumferentially around the opening portion 20, and one end of the buffer portion 21 near the first surface 10 is integrally connected to the cover body 1. Thus, the buffer portion 21 serves as an intermediate transition structure connecting the opening portion 20 and the cover body 1, thereby extending the heat conduction path length between the opening portion 20 and the cover body 1. Specifically, during the welding and encapsulation of the cover body 1 and the battery casing 1001, the high temperature generated during welding must pass through the buffer portion 21 before being transferred to the opening portion 20. The buffer portion 21 effectively blocks and disperses the welding thermal stress, reducing the impact on the opening portion 20, especially the burst section 200, improving the stability and reliability of the explosion-proof valve 2, and increasing production yield. It should be noted that in the cover plate assembly of this application embodiment, the buffer part 21, the opening part 20 and the cover plate body 1 are all integrally formed structures. The materials of the buffer part 21, the opening part 20 and the cover plate body 1 are continuous and there is no welding interface, which not only ensures the sealing performance, but also improves the structural strength of the explosion-proof valve 2.

[0048] The opening section 20 is provided with a bursting section 200 and at least one reinforcing section 22, which are spaced apart. This creates a certain gap between the bursting section 200 and the reinforcing section 22. This gap effectively reduces mutual interference between the bursting section 200 and the reinforcing section 22 during molding, thereby suppressing the possibility of deformation of the bursting section 200 or the reinforcing section 22 and improving the molding rate of the explosion-proof valve.

[0049] It should be noted that the burst section 200 can be a groove structure that reduces the local structural strength of the opening part 20. For example, the burst section 200 can be a groove formed by laser engraving or mechanical scribing. Along the thickness direction of the cover plate body 1, the cross-section of the groove can be V-shaped. The depth, length, and shape of the burst section 200 together determine the opening pressure of the explosion-proof valve 2. Specifically, when the internal pressure of the battery cell exceeds the preset valve opening pressure, the burst section 200 can at least partially break, causing the opening part 20 to rupture, thereby opening the explosion-proof valve 2 to provide an emergency pressure relief channel for the battery cell. In addition, the stiffening part 22 is used to increase the rigidity of the opening part 20 to improve its resistance to deformation and reduce the deformation of the opening part 20 when heated or compressed, thereby reducing the risk of cracking of the explosion-proof valve.

[0050] In some embodiments, refer to Figure 5In the specific implementation shown, when there is only one reinforcing part 22, it can be located in the central region of the opening part 20. This is equivalent to localized strength enhancement in the area of ​​the opening part 20 most prone to deformation, thus improving its resistance to bending under pressure loads. This allows the opening part 20 to maintain its planar shape more stably before reaching the set opening pressure threshold, ensuring that pressure is transmitted more evenly and predictably to the surrounding pre-set grooves, which helps to control the opening pressure range of the explosion-proof valve 2 more accurately. Of course, in other embodiments, the reinforcing part 22 can also be located in other areas of the opening part 20, and the number of reinforcing parts 22 can also be multiple.

[0051] The reinforcing portion 22 is a protruding structure that protrudes toward the first surface 10 and / or the second surface 11. It is understood that the structural form of the reinforcing portion 22 includes, but is not limited to: a protruding structure protruding only toward the first surface 10, a protruding structure protruding only toward the second surface 11, or a protruding structure protruding toward both the first surface 10 and the second surface 11. For example, the forming process of the protruding structure includes, but is not limited to, stamping, extrusion, injection molding, etc., and can be selected according to the actual situation.

[0052] The blasting section 200 is arranged circumferentially around all the reinforcing parts 22. On a plane perpendicular to the thickness direction of the cover plate body 1, the projected area of ​​all the reinforcing parts 22 is S1, and the projected area of ​​the region enclosed by the inner edge of the blasting section 200 near the center of the explosion-proof valve 2 is S2, satisfying: 1% ≤ S1 / S2 ≤ 70%. For example, S1 / S2 can be 1%, 8%, 12%, 25%, 32%, 41%, 53%, 61%, 70%, etc., or any value between any two of the above. The ratio of S1 / S2 represents the proportion of the area of ​​the blasting region enclosed by the reinforcing parts 22 relative to the blasting area enclosed by the blasting section 200. If the ratio of S1 / S2 is less than 1%, the area of ​​the reinforcing part 22 is too small, and its reinforcing effect on the opening part 20 is small. If the ratio of S1 / S2 is greater than 70%, the area of ​​the reinforcing part 22 is too large, which can easily affect the structure of the explosion section 200 during the stamping process, thus leading to an increase in the defect rate of the explosion-proof valve 2. Therefore, S1 and S2 are considered comprehensively, so that S1 / S2 is limited to the range of 1% to 70%, which can ensure both the reinforcing effect on the opening part 20 and the forming of the explosion-proof valve 2, thereby improving the yield rate of battery production and reducing production costs.

[0053] In some embodiments, please refer to Figure 7 or Figure 8The reinforcing portion 22 has a hollow structure and protrudes toward either the first surface 10 or the second surface 11. It can be understood that the hollow structure of the reinforcing portion 22 includes, but is not limited to, a protrusion protruding only toward the first surface 10 or a protrusion protruding only toward the second surface 11. For example, see... Figure 7 In the specific embodiment shown, the reinforcing part 22 is a protruding structure protruding towards the first surface 10, and the interior of the protruding structure is hollow, with a shape similar to an upwardly bulging dome. The hollow reinforcing part 22 can improve the local stiffness of the opening part 20, and because the reinforcing part 22 is hollow, it can achieve a lighter weight and increase the energy density of the battery cell while maintaining the same external dimensions.

[0054] In some embodiments, the orthographic projection shape of the reinforcing portion 22 on a plane perpendicular to the thickness direction of the cover plate body 1 can be circular, elliptical, or elongated, etc. Figure 11 or Figure 12 Example shown.

[0055] Of course, in other embodiments, the reinforcing portion 22 may also be a solid structure and protrude toward the first surface 10 and / or the second surface 11. It is understood that the solid structure of the reinforcing portion 22 includes, but is not limited to: a solid protrusion protruding only toward the first surface 10, a solid protrusion protruding only toward the second surface 11, or a solid structure protruding toward both the first surface 10 and the second surface 11. This localized thickening increases the resistance of the opening portion 20 to deformation.

[0056] In some embodiments, each reinforcing portion 22 includes at least one protruding structure disposed along its thickness direction. It will be understood that the reinforcing portion 22 is composed of at least one protruding structure along the thickness direction of the reinforcing portion 22 or along the thickness direction of the cover plate body 1, for example, see reference... Figure 7 The reinforcing portion 22 includes a protruding structure. In other embodiments, the reinforcing portion 22 includes at least two protruding structures, for example, see [reference needed]. Figure 8 The reinforcing part 22 includes a first protrusion 220 and a second protrusion 221. The second protrusion 221 is located on the side of the first protrusion 220 away from the first surface 10 and protrudes in a direction away from the first protrusion 220. Thus, the first protrusion 220 and the second protrusion 221 form a protrusion structure stacked along the thickness direction of the cover plate body 1, thereby constituting the reinforcing part 22. Compared to a single-layer protrusion, the double-layer protrusion formed by the first protrusion 220 and the second protrusion 221 improves the overall rigidity of the reinforcing part 22 and further increases the strength of the opening part 20. In some embodiments, referring to... Figure 8 In the specific embodiment shown, both the first protrusion 220 and the second protrusion 221 can be hollow structures.

[0057] In some embodiments, please refer to Figure 4 and Figure 5 The cover plate assembly 1000 also includes a pole post 3 for electrical connection with the electrode tab of the battery cell. The pole post 3 is disposed on the cover plate body 1. Specifically, the connection between the pole post 3 and the cover plate body 1 can be fixed in the mounting through hole of the cover plate body 1 by riveting, welding or by using a sealing clip.

[0058] At least a portion of the electrode post 3 protrudes from the first surface 10, forming a first electrical connection surface 30. The first electrical connection surface 30 is located on the side of the first surface 10 opposite to the second surface 11, and is used for electrical connection with a busbar or external electrical component. The electrode post 3 also has a second electrical connection surface 31, which is arranged opposite to the first electrical connection surface 30 along the thickness direction of the cover plate body 1, and is used for connection with the tab of the battery cell. In some embodiments, to increase the contact area between the second electrical connection surface 31 and the tab, an adapter piece may be provided between the second electrical connection surface 31 and the tab.

[0059] Please refer to Figure 5 Along the thickness direction of the cover plate body 1, the distance between the first electrical connection surface 30 and the first surface 10 is A2, the thickness of the cover plate body 1 is A1, and the distance between the end of the explosion-proof valve 2 away from the first surface 10 and the first surface 10 is A, satisfying: -0.5×A1≤A≤A2. Through the above settings, it can be ensured that the buffer part 21 of the explosion-proof valve 2 is in a suitable position in the height direction of the battery cell, which can both ensure that the explosion-proof valve 2 is easier to form and avoid reducing the overall space utilization rate inside the battery cell.

[0060] Specifically, when A is less than -0.5×A1, that is, the buffer part 21 of the explosion-proof valve 2 is recessed below the first surface 10 of the cover plate body 1, the material flow is difficult during the stamping process, making it difficult to form the explosion-proof valve 2. When A is greater than A2, that is, along the thickness direction of the cover plate body 1, the explosion-proof valve 2 is higher than the first electrical connection surface 30 of the pole post 3, which will occupy extra space inside the battery cell and reduce the space utilization rate inside the battery cell.

[0061] In some embodiments, please refer to Figure 9The buffer section 21 includes a first buffer segment 210, a second buffer segment 211, a bent segment 214, a third buffer segment 212, and a fourth buffer segment 213. The first buffer segment 210, the third buffer segment 212, the fourth buffer segment 213, the bent segment 214, and the second buffer segment 211 are sequentially connected from the cover plate body 1 to the opening portion 20. The buffer section 21 formed by the first buffer segment 210, the third buffer segment 212, the fourth buffer segment 213, the bent segment 214, and the second buffer segment 211, together with the opening portion 20, forms a cavity 215. The cavity 215 communicates with the interior of the housing 1001, so that when the pressure inside the housing 1001 increases, the pressure can be quickly applied to the explosion-proof valve 2 through the cavity 215. The first buffer segment 210, the third buffer segment 212, the fourth buffer segment 213, the bent segment 214, and the second buffer segment 211 are integrally formed structures.

[0062] In some embodiments, please refer to Figure 9 The first buffer section 210 extends along a direction perpendicular to the thickness of the cover plate body 1. It can be understood that the extension direction of the first buffer section 210 refers to its width direction, meaning that both ends of the first buffer section 210 in its width direction are connected to the cover plate body 1 and the third buffer section 212, respectively. One end of the third buffer section 212 is connected to the first buffer section 210, and the other end of the third buffer section 212 extends along the thickness direction of the cover plate body 1. It can be understood that the extension direction of the third buffer section 212 refers to its width direction, meaning that both ends of the third buffer section 212 in its width direction are connected to the first buffer section 210 and the fourth buffer section 213, respectively. One end of the fourth buffer section 213 is connected to the third buffer section 212, and the other end of the fourth buffer section 213 is inclined away from the opening part 20. It can be understood that one end of the fourth buffer section 213 in its width direction is connected to the third buffer section 212, and the other end is inclined away from the central axis of the explosion-proof valve 2. One end of the second buffer section 211 is connected to the fourth buffer section 213 via the bent section 214, and the other end of the second buffer section 211 is inclined toward the opening part 20. It can be understood that one end of the second buffer section 211 in the width direction is connected to the fourth buffer section 213 via the bent section 214, and the other end is inclined toward the central axis of the explosion-proof valve 2 and connected to the opening part 20. Thus, within a limited height space, a curved buffer part 21 is formed, consisting of the first buffer section 210, the third buffer section 212, the fourth buffer section 213, the bent section 214, and the second buffer section 211. When the battery cell housing 1001 is welded to the cover plate body 1, heat will pass through the first buffer section 210, the third buffer section 212, the fourth buffer section 213, the bent section 214, and the second buffer section 211 to the opening part 20, thereby increasing the heat conduction path and ensuring the stability and reliability of the explosion-proof valve 2.

[0063] Reference Figure 5 and Figure 9 The first buffer section 210 is connected to the cover body 1, and the second buffer section 211 is connected to the opening part 20. The first buffer section 210 has a first wall surface 2111, which can be the surface facing the outside of the battery cell along the thickness direction of the first buffer section 210. The opening part 20 has a first opening surface 201 connected to the first wall surface 2111, which can be the surface facing the outside of the battery cell. The included angle between the first wall surface 2111 and the first opening surface 201 is α, which satisfies: 90°≤α≤180°. For example, α can be 90°, 95°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, 70°, 180°, etc., or any value between any two of the above values. Therefore, 'a' is limited to the range of 90° to 180° to ensure that the explosion-proof valve 2 is easily formed by the stamping process while preventing the outer periphery of the buffer section 21 from interfering with the cover plate body 1. When 'a' is less than 90°, the angle between the second buffer section 211 and the opening section 20 is too small, making it difficult to form from the perspective of the stamping process. When 'a' is greater than 180°, the edge of the buffer section 21 will bend downwards (i.e., bend towards the cover plate body 1), which can easily cause structural interference with the cover plate body 1.

[0064] In some embodiments, the following condition is satisfied: 120°≤a≤150°. For example, a can be 120°, 130°, 140° or 150°, or any value between any two of the above values. This setting can better realize the molding of the explosion-proof valve 2 and improve the space utilization rate.

[0065] In some embodiments, please refer to Figure 9 and Figure 10 On a plane perpendicular to the thickness direction of the cover plate body 1, the projected area of ​​the region enclosed by the inner edge of the third buffer section 212 near the center of the explosion-proof valve 2 is S3, satisfying: 70%≤S2 / S3≤95%. It can be understood that the region enclosed by the inner edge of the third buffer section 212 near the center of the explosion-proof valve 2 can be formed by the third buffer section 212 extending circumferentially along the first buffer section 210 and enclosing a through hole 2120, such as... Figure 10 As shown, on the plane perpendicular to the thickness direction of the cover plate body 1, S3, which is the orthogonal projection area of ​​the through hole 2120, satisfies: 70%≤S2 / S3≤95%. For example, the ratio of S2 / S3 can be 70%, 75%, 80%, 85%, 90%, 95%, etc., or any value between any two of the above values.

[0066] Therefore, if the S2 / S3 ratio is less than 70%, the area of ​​the explosion zone enclosed by the explosion section 200 is small. During battery thermal runaway, the opening surface is small, making it impossible to release internal pressure and ejected materials in a timely and sufficient manner, thus affecting the battery's thermal runaway performance. If the S2 / S3 ratio is greater than 95%, the area of ​​the explosion zone enclosed by the explosion section 200 is too large, which can easily affect the explosion section during stamping, leading to an increased defect rate. Therefore, the S2 / S3 ratio is limited to 70% ≤ S2 / S3 ≤ 95%, which ensures both the area of ​​the explosion zone and good molding quality.

[0067] In some embodiments, please refer to Figure 9 On a plane perpendicular to the thickness direction of the cover plate body 1, the orthographic projection area of ​​the region enclosed by the outer edge of the third buffer section 212 away from the center of the explosion-proof valve 2 is S4, and the orthographic projection area of ​​the region enclosed by the outer edge of the first buffer section 210 away from the center of the explosion-proof valve 2 is S5, satisfying: 60%≤S4 / S5≤90%. For example, the ratio of S4 / S5 can be 60%, 65%, 70%, 75%, 80%, 85%, 90%, etc., or any value between any two of the above values.

[0068] Therefore, if the S4 / S5 ratio is less than 65%, the area enclosed by the outer edge of the third buffer section 212 is too small, resulting in an insufficient ventilation area and opening area for the explosion-proof valve 2. This prevents timely and sufficient release of internal pressure and ejected materials, affecting the safety of the battery during thermal runaway. Conversely, if the S4 / S5 ratio is greater than 90%, the area enclosed by the outer edge of the third buffer section 212 is too large, making the explosion-proof valve 2 difficult to mold and leading to an increased defect rate.

[0069] To further verify the influence of the S1 / S2 ratio on the opening and forming effect of the explosion-proof valve, this application conducted stamping forming experiments and battery thermal runaway experiments on the explosion-proof valve under different ratios. The specific experimental parameters and results are shown in Table 1.

[0070] Table 1 As shown in Table 1, in Example 1, the area of ​​S1 is 1 mm. 2 The area of ​​S2 is 150 mm². 2 Therefore, the ratio of S1 / S2 is 0.67%. This ratio is too small, failing to satisfy the condition: 1% ≤ S1 / S2 ≤ 70%. The area of ​​the reinforcing part 22 is too small, resulting in a minimal reinforcing effect on the opening; its use is not recommended. In Examples 2-11, the area of ​​S1 is 15 mm². 2 -105mm 2 The area of ​​S2 is 150 mm². 2The ratio of S1 / S2 ranges from 10% to 70%. It satisfies the condition: 1% ≤ S1 / S2 ≤ 70%. As a result, the molding yield of explosion-proof valve 2 is ≥99.88%, and the opening pressure of explosion-proof valve 2 meets the requirements. In Example 12, the area of ​​S1 is 140 mm². 2 The area of ​​S2 is 150 mm². 2 Therefore, the ratio of S1 / S2 is 93.33%. The ratio of S1 / S2 is too large, failing to satisfy the condition: 1% ≤ S1 / S2 ≤ 70%. The area of ​​the reinforcing part 22 is too large, which can easily affect the scoring of the bursting section 200 during the stamping process, resulting in a defect rate ≥ 6.5%. In Example 13, the area of ​​S1 is 20 mm². 2 The area of ​​S2 is 50 mm². 2 Therefore, the ratio of S1 / S2 is 40%. This satisfies the condition: 1% ≤ S1 / S2 ≤ 70%. As a result, the molding yield of explosion-proof valve 2 is ≥99.87%, and the opening pressure of the explosion-proof valve meets the requirements. In Example 14, the area of ​​S1 is 150 mm². 2 The area of ​​S2 is 300 mm². 2 Therefore, the ratio of S1 / S2 is 50%. This satisfies the condition: 1% ≤ S1 / S2 ≤ 70%. As a result, the molding yield of explosion-proof valve 2 is ≥99.87%, and the opening pressure of the explosion-proof valve meets the requirements. In Example 15, the area of ​​S1 is 250 mm². 2 The area of ​​S2 is 500 mm². 2 Therefore, the ratio of S1 / S2 is 50%. This satisfies the condition: 1% ≤ S1 / S2 ≤ 70%. As a result, the molding yield of explosion-proof valve 2 is ≥99.87%, and the opening pressure of the explosion-proof valve meets the requirements. In Example 16, the area of ​​S1 is 500 mm². 2 The area of ​​S2 is 1000 mm². 2 The ratio of S1 / S2 is 50%. This satisfies the condition: 1% ≤ S1 / S2 ≤ 70%. As a result, the molding yield of explosion-proof valve 2 is ≥ 99.87%, and the opening pressure of the explosion-proof valve meets the requirements.

[0071] To further verify the influence of the S2 / S3 ratio on the opening and forming effect of the explosion-proof valve, this application conducted stamping forming experiments and battery thermal runaway experiments on the explosion-proof valve under different ratios. The specific experimental parameters and results are shown in Table 2.

[0072] Table 2 As shown in Table 2, in Example 1, the area of ​​S2 is 50 mm². 2 The area of ​​S3 is 150 mm². 2Therefore, the ratio of S2 / S3 is 33.33%. This ratio is too small, failing to satisfy the condition: 70% ≤ S2 / S3 ≤ 95%. Consequently, the area of ​​the blast zone enclosed by the blasting section 200 is relatively small. During battery thermal runaway, the opening area of ​​the explosion-proof valve is too small, making it unable to release internal pressure and ejected material in a timely and sufficient manner, thus affecting the battery's thermal runaway outcome. Therefore, its use is not recommended. In Examples 2-11, the area of ​​S2 is within the range of 105 mm². 2 -142.5mm 2 The area of ​​S3 is 150 mm². 2 Therefore, the ratio of S2 / S3 ranges from 70% to 95%. It satisfies the condition: 70% ≤ S2 / S3 ≤ 95%. As a result, during the molding process of the explosion-proof valve, the molding yield is ≥99.78%, and the opening pressure of the explosion-proof valve meets the requirements. In Example 12, the area of ​​S2 is 150 mm². 2 The area of ​​S3 is 150 mm². 2 Therefore, the ratio of S2 / S3 is 100%. The ratio of S2 / S3 is too large, failing to satisfy the condition: 70% ≤ S2 / S3 ≤ 95%. This results in an excessively large area of ​​the blasting region enclosed by the blasting section 200. During stamping, this can easily affect the scoring of the blasting section 200, leading to an increased defect rate (≥8%). In Example 13, the area of ​​S2 is 40 mm². 2 The area of ​​S3 is 50 mm². 2 Therefore, the ratio of S2 / S3 is 80%. This satisfies the condition: 70% ≤ S2 / S3 ≤ 95%. As a result, during the molding process of the explosion-proof valve, the molding yield is ≥99.75%, and the opening pressure of the explosion-proof valve meets the requirements. In Example 14, the area of ​​S2 is 250 mm². 2 The area of ​​S3 is 300 mm². 2 Therefore, the ratio of S2 / S3 is 83.33%. This satisfies the condition: 70% ≤ S2 / S3 ≤ 95%. As a result, during the explosion-proof valve molding process, the molding yield is ≥99.75%, and the explosion-proof valve opening pressure meets the requirements. In Example 15, the area of ​​S2 is 450 mm². 2 The area of ​​S3 is 500 mm². 2 Therefore, the ratio of S2 / S3 is 90%. This satisfies the condition: 70% ≤ S2 / S3 ≤ 95%. As a result, during the molding process of the explosion-proof valve, the molding yield is ≥99.75%, and the opening pressure of the explosion-proof valve meets the requirements. In Example 16, the area of ​​S2 is 900 mm². 2 The area of ​​S3 is 1000 mm². 2 Therefore, the ratio of S2 / S3 is 90%. This satisfies the condition: 70% ≤ S2 / S3 ≤ 95%. As a result, during the molding process of the explosion-proof valve, the molding yield is ≥ 99.75%, and the opening pressure of the explosion-proof valve meets the requirements.

[0073] To further verify the influence of the S4 / S5 ratio on the opening and forming effect of the explosion-proof valve, this application conducted stamping forming experiments and battery thermal runaway experiments on the explosion-proof valve under different ratios. The specific experimental parameters and results are shown in Table 3. Table 3 As shown in Table 3, in Example 1, the area of ​​S4 is 100 mm². 2 The area of ​​S5 is 200 mm². 2 Therefore, the ratio of S4 / S5 is 50%. The ratio of S4 / S5 is too small, failing to satisfy the condition: 60% ≤ S4 / S5 ≤ 90%. As a result, the ventilation area of ​​explosion-proof valve 2 is too small, and the opening area of ​​the explosion-proof valve is too small, affecting the battery thermal runaway outcome; its use is not recommended. In Examples 2-11, the area of ​​S4 is within the range of 120 mm². 2 -180mm 2 The area of ​​S5 is 200 mm². 2 Therefore, the ratio of S4 / S5 ranges from 60% to 90%. It satisfies the condition: 60% ≤ S4 / S5 ≤ 90%. As a result, during the molding process of the explosion-proof valve, the molding yield is ≥99.85%, and the opening pressure of the explosion-proof valve meets the requirements. In Example 12, the area of ​​S4 is 195 mm². 2 The area of ​​S5 is 200 mm². 2 Therefore, the ratio of S4 / S5 is 97.5%. This ratio is too large and does not satisfy the condition: 60% ≤ S4 / S5 ≤ 90%. As a result, molding is difficult during the explosion-proof valve molding process, and the defect rate is ≥10%. In Example 13, the area of ​​S4 is 35 mm². 2 The area of ​​S5 is 50mm². 2 Therefore, the ratio of S4 / S5 is 70%. This satisfies the condition: 60% ≤ S4 / S5 ≤ 90%. As a result, during the explosion-proof valve molding process, the molding yield is ≥99.88%, and the explosion-proof valve opening pressure meets the requirements. In Example 14, the area of ​​S4 is 250 mm². 2 The area of ​​S5 is 300 mm². 2 Therefore, the ratio of S4 / S5 is 83.33%. This satisfies the condition: 60% ≤ S4 / S5 ≤ 90%. As a result, during the explosion-proof valve molding process, the molding yield is ≥99.88%, and the explosion-proof valve opening pressure meets the requirements. In Example 15, the area of ​​S4 is 400 mm². 2 The area of ​​S5 is 500 mm². 2 Therefore, the ratio of S4 / S5 is 80%. This satisfies the condition: 60% ≤ S4 / S5 ≤ 90%. As a result, during the explosion-proof valve molding process, the molding yield is ≥99.88%, and the explosion-proof valve opening pressure meets the requirements. In Example 16, the area of ​​S4 is 900 mm². 2The area of ​​S5 is 1000 mm². 2 Therefore, the ratio of S4 / S5 is 90%. This satisfies the condition: 60% ≤ S4 / S5 ≤ 90%. As a result, during the molding process of the explosion-proof valve, the molding yield is ≥ 99.88%, and the opening pressure of the explosion-proof valve meets the requirements.

[0074] To further verify the influence of the included angle α between the first wall surface 2111 of the second buffer section 211 and the first opening surface 201 of the opening part 20 on the explosion-proof valve 2, this application studied the stamping forming experiment of the explosion-proof valve under different included angle α conditions. The specific experimental parameters and results are shown in Table 4.

[0075] Table 4 As shown in Table 4, in Example 1, the angle α is 70°, which is less than 90° and does not meet the requirement of 90°≤a≤180°. Therefore, it is difficult to form the explosion-proof valve during stamping and is not recommended. In Examples 2-9, the included angle α is within the range of 90°-180°, satisfying 90°≤a≤180°. Therefore, the forming yield is ≥99.6% when stamping the explosion-proof valve. In Example 10, the included angle α is 205°, which is greater than 180° and does not meet the requirement of 90°≤a≤180°. Therefore, when stamping the explosion-proof valve, the edge of the explosion-proof valve bends downward, which may easily interfere with the cover plate body 1. It is not recommended. Thus, it is shown that when the included angle α is within the range of 90°≤a≤180°, it can ensure that the explosion-proof valve 2 is easy to form through the stamping process with a high yield, and it can also avoid interference with the cover plate body 1.

[0076] To further verify the influence of the position of the explosion-proof valve 2 along the thickness direction of the cover plate body 1 on the forming quality and spatial layout, this application embodiment studied the stamping experiment of explosion-proof valve 2 with different sizes of A1, A2 and A. The specific experimental parameters and results are shown in Table 5.

[0077] Table 5 As shown in Table 5 above, in Example 1, A1 is 2mm, A2 is 3.2mm, and A is -1.45mm. The value of A is too small, not meeting the range of -0.5×A1≤A≤A2. During the stamping of the explosion-proof valve 2, forming is difficult, and the defect rate is ≥5.6%. In Examples 2-13, A1 is 2mm, A2 is 3.2mm, and A ranges from -1mm to 3.2mm, meeting the range of -0.5×A1≤A≤A2. Result: During the stamping of the explosion-proof valve, the forming yield is ≥99.8%, and the opening pressure of the explosion-proof valve meets the requirements. In Example 14, A1 is 2mm, A2 is 3.2mm, and A is 4. The value of A is too large, not meeting the range of -0.5×A1≤A≤A2. Result: During the stamping of the explosion-proof valve, the explosion-proof valve 2 is higher than the surface of the electrode post 3, affecting the space utilization of the battery cell.

[0078] In Example 15, A1 is 1.5mm, A2 is 3.2mm, and A is 0. The end of the explosion-proof valve 2 away from the first surface (10) is flush with the first surface 10, satisfying -0.5×A1≤A≤A2. In Example 16, A1 is 3mm, A2 is 3.2mm, and A is 0. That is, the end of the explosion-proof valve 2 away from the first surface (10) is flush with the first surface 10, satisfying -0.5×A1≤A≤A2. In Example 17, A1 is 2mm, A2 is 5mm, and A is 0mm. That is, the end of the explosion-proof valve 2 away from the first surface (10) is flush with the first surface 10, satisfying -0.5×A1≤A≤A2. In Example 18, A1 is 2mm, A2 is 2.2mm, and A is 0mm. This means the end of the explosion-proof valve 2 furthest from the first surface (10) is flush with the first surface 10, satisfying -0.5×A1≤A≤A2. In Example 19, A1 is 2mm, A2 is 1mm, and A is 0mm. This means the end of the explosion-proof valve 2 furthest from the first surface (10) is flush with the first surface 10, satisfying -0.5×A1≤A≤A2. In Example 20, A1 is 2mm, A2 is 0.2mm, and A is 0mm. This means the end of the explosion-proof valve 2 furthest from the first surface (10) is flush with the first surface 10, satisfying -0.5×A1≤A≤A2. Results of Examples 15 to 20: During the stamping of the explosion-proof valve, the forming yield is ≥99.8%, and the opening pressure of the explosion-proof valve meets the requirements. This indicates that satisfying -0.5×A1≤A≤A2 ensures that the stamping process is easy to form and yields a high yield, while also avoiding affecting the internal space utilization of the battery cell.

[0079] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A cover plate assembly, characterized in that, include: The cover plate body includes a first surface and a second surface, wherein the first surface and the second surface are disposed opposite to each other along the thickness direction of the cover plate body; An explosion-proof valve is disposed on the cover plate body and integrally formed with the cover plate body; the explosion-proof valve includes an opening part and a buffer part, wherein the buffer part is arranged circumferentially around the opening part, and one end of the buffer part near the first surface is connected to the cover plate body; the opening part is provided with a bursting section and at least one reinforcing part, the bursting section and the reinforcing part are arranged at intervals, the reinforcing part is a protruding structure protruding towards the first surface and / or the second surface, the bursting section is arranged circumferentially around all the reinforcing parts, and on a plane perpendicular to the thickness direction of the cover plate body, the orthographic projection area of ​​all the reinforcing parts is S1, and the orthographic projection area of ​​the area enclosed by the inner edge of the bursting section near the center of the explosion-proof valve is S2; The following condition must be met: 1% ≤ S1 / S2 ≤ 70%.

2. The cover plate assembly according to claim 1, characterized in that, The reinforcing part has a hollow structure and protrudes toward the first surface or the second surface.

3. The cover plate assembly according to claim 2, characterized in that, Each of the reinforcing parts includes at least one protruding structure disposed along its thickness direction.

4. The cover plate assembly according to claim 1, characterized in that, Also includes: A pole is disposed on the cover plate body, and at least a portion of the pole protrudes from the first surface and forms a first electrical connection surface. Along the thickness direction of the cover plate body, the distance between the first electrical connection surface and the first surface is A2, the thickness of the cover plate body is A1, and the distance between the end of the explosion-proof valve away from the first surface and the first surface is A, satisfying: -0.5×A1≤A≤A2.

5. The cover plate assembly according to any one of claims 1-4, characterized in that, The buffer section includes at least a first buffer segment and a second buffer segment. The first buffer segment is connected to the cover plate body, and the second buffer segment is connected to the opening section. The second buffer segment has a first wall surface, and the opening section has a first opening surface connected to the first wall surface. The included angle between the first wall surface and the first opening surface is α, which satisfies: 90°≤α≤180°.

6. The cover plate assembly according to claim 5, characterized in that, The buffer section further includes a bending section, a third buffer section, and a fourth buffer section; wherein the first buffer section, the third buffer section, the fourth buffer section, the bending section, and the second buffer section are sequentially connected from the cover plate body to the opening section; The first buffer section extends along a direction perpendicular to the thickness of the cover plate body. One end of the third buffer section is connected to the first buffer section, and the other end of the third buffer section extends along the thickness of the cover plate body. One end of the fourth buffer section is connected to the third buffer section, and the other end of the fourth buffer section is inclined away from the opening. One end of the second buffer section is connected to the fourth buffer section through the bending section, and the other end of the second buffer section is inclined towards the opening.

7. The cover plate assembly according to claim 6, characterized in that, On a plane perpendicular to the thickness direction of the cover plate body, the orthographic projection area of ​​the region enclosed by the inner edge of the third buffer section near the center of the explosion-proof valve is S3, which satisfies: 70%≤S2 / S3≤95%.

8. The cover plate assembly according to claim 7, characterized in that, On a plane perpendicular to the thickness direction of the cover plate body, the orthographic projection area of ​​the region enclosed by the outer edge of the third buffer section away from the center of the explosion-proof valve is S4, and the orthographic projection area of ​​the region enclosed by the outer edge of the first buffer section away from the center of the explosion-proof valve is S5, satisfying: 60%≤S4 / S5≤90%.

9. A single battery cell, characterized in that, include: A housing having an opening; The cover assembly according to any one of claims 1 to 8 is connected to the opening of the housing.

10. An electrical device, characterized in that, include: Electricity-consuming entities; At least one battery cell according to claim 9, wherein the battery cell is electrically connected to the power-consuming body.

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