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 has a first surface and a second surface. The explosion-proof valve is arranged on the cover plate body and is in an integral forming 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 circumference of the opening part. One end of the buffer part away from the opening part is connected with the cover plate body. The opening part is provided with a burst section and a reinforcing part. The burst section and the reinforcing part are arranged at intervals. The reinforcing part is in a protruding structure that protrudes towards the first surface and / or the second surface. In the thickness direction of the cover plate body, the distance between one end of the explosion-proof valve away from the first surface and the surface of the opening part is A. In the thickness direction of the cover plate body, the distance between the reinforcing part and the surface of the opening part is A1. 0 <= A1 <= A is met. Therefore, the stability of the explosion-proof valve is ensured, and the yield of battery production is improved.

Description

Technical Field

[0001] This invention 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, including: a cover plate body and an explosion-proof valve. The cover plate body has a first surface and a second surface, which are arranged 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 away from the opening portion is connected to the cover plate body. The opening portion is provided with a bursting section and a reinforcing section, which are spaced apart. The reinforcing section has a protruding structure protruding towards the first surface and / or the second surface. Along the thickness direction of the cover plate body, the distance between the end of the explosion-proof valve away from the first surface and the surface of the opening portion is A, and along the thickness direction of the cover plate body, the distance between the end of the reinforcing section away from the first surface and the surface of the opening portion is A1; satisfying: 0≤A1≤A.

[0005] In one or more embodiments of this application, the reinforcing part has a solid structure, and the thickness of the reinforcing part along the thickness direction of the cover plate body is B; the thickness of the opening part is B1; satisfying: 1≤B / B1≤10; and / or, The thickness of the opening is B1, which satisfies the condition: 0.15mm≤B1≤0.4mm.

[0006] In one or more embodiments of this application, the reinforcing part has a hollow structure and protrudes toward the first surface and / or the second surface of the cover plate body; On a plane perpendicular to the thickness direction of the cover plate body, the distance T between the edge of the reinforcing part and the bursting section satisfies: T≥3mm.

[0007] In one or more embodiments of this application, the buffer portion includes at least a first buffer segment and a second buffer segment. The second buffer segment is connected to the opening portion. The second buffer segment has a first wall surface. 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°.

[0008] In one or more embodiments of this application, 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 connected sequentially from the cover plate body to the opening section.

[0009] In one or more embodiments of this application, the first buffer section extends along the direction perpendicular to the thickness of the cover plate body, one end of the third buffer section is connected to the first buffer section, 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, the other end of the fourth buffer section is inclined in a direction 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 in a direction 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 and along the width direction of the cover plate body, the width of the orthographic projection of the explosion-proof valve is C, and the width of the orthographic projection of the bent section of the explosion-proof valve is C1, satisfying: 0.7≤C1 / C≤1.3; and / or, On a plane perpendicular to the thickness direction of the cover plate body, along the length direction of the cover plate body, the maximum length of the orthographic projection of the explosion-proof valve is D, and the maximum length of the orthographic projection of the bent section of the explosion-proof valve is D1, satisfying: 0.7≤D1 / D≤1.3.

[0011] In one or more embodiments of this application, it further includes: a pole post, which is disposed on the cover plate body, at least a portion of which 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 A4, the thickness of the cover plate body is A3, and the distance between the end of the explosion-proof valve away from the first surface and the first surface is A2, satisfying: -0.5×A3≤A2≤A4.

[0012] Secondly, this application provides a battery cell, comprising: a housing and a cover assembly as described in any one of the first aspects, the housing having an opening; the cover assembly being 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; 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 cover plate assembly 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 burst 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 to the cover plate. Simultaneously, a buffer section is provided between the opening part and the cover plate body. This 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 burst section. A reinforcing section is provided on the opening part to further increase the rigidity of the explosion-proof valve, thereby improving its resistance to deformation and reducing deformation when the explosion-proof valve is heated or compressed, thus reducing the risk of cracking. Further control is applied along the thickness direction of the cover plate body. The relationship between the distance A between the end of the explosion-proof valve away from the first surface and the surface of the opening part, and the distance A1 between the reinforcing part and the opening part, satisfies: 0≤A1≤A. This ensures that the height of the reinforcing part protrudes beyond the explosion-proof valve, guaranteeing that the reinforcing part, as a localized strengthening structure, will not occupy additional internal space of the battery pack due to excessive protrusion. Simultaneously, it strengthens the local rigidity of the opening part, enabling the explosion-proof valve to effectively resist stress and structural deformation caused by heat conduction in subsequent processes (such as welding the shell and cover plate body). This makes the explosion-proof valve less prone to cracking, thus ensuring the structural integrity of the burst section, stabilizing the preset opening pressure of the explosion-proof valve, guaranteeing the reliability of the explosion-proof valve's burst, and 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 structure 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 yes Figure 4 A magnified structural diagram of region E in the middle.

[0021] Figure 6 This is a partially enlarged cross-sectional view of the cover plate body and the explosion-proof valve in the cover plate assembly provided in the embodiments of this application.

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

[0023] Figure 8 yes Figure 7 Enlarged structural diagram at point E2.

[0024] Figure 9 This is a schematic diagram of the structure of the reinforcing part provided in some embodiments of this application.

[0025] Figure 10 This is a schematic diagram of the structure of the reinforcement provided in some other embodiments of this application.

[0026] Figure 11 yes Figure 7 A magnified structural diagram at point E1.

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

[0028] Figure 13 This is a cross-sectional schematic diagram of the cover plate assembly provided in some embodiments of this application along the width direction of the cover plate body.

[0029] Figure 14 This is a cross-sectional schematic diagram of the cover plate assembly provided in some embodiments of this application along the length of the cover plate body.

[0030] Figure 15 This is a top view of a cover plate assembly provided in other embodiments of this application.

[0031] In the diagram: 100 - Electrical device; 110 - Electrical main body; 111 - Battery compartment; 120 - Battery pack; 121 - Battery cell; 122 - Housing; 1000 - Cover assembly; 1001 - Housing; 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; 2111 - First wall surface; 3 - Terminal post; 30 - First electrical connection surface; 31 - Second electrical connection surface. Detailed Implementation

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] The technical solution of this application will now be described in detail with reference to the accompanying drawings.

[0037] 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.

[0038] 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.

[0039] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] Please continue reading. Figure 3 The battery cell 121 may include a housing 1001, a 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 cell and electrolyte. The opening is used to place the 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 cell has tabs that are electrically connected to the cover assembly 1000.

[0045] 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 embodiments, 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 embodiments, 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.

[0046] 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 opening of the housing 1001. The cover body 1 is connected to the housing 1001 and seals the opening to protect the battery cell and prevent electrolyte leakage. Figure 4In 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] The explosion-proof valve 2 includes an opening section 20 and a buffer section 21. The buffer section 21 is arranged circumferentially around the opening section 20, and the end of the buffer section 21 away from the opening section 20 is integrally connected to the cover plate body 1. Thus, the buffer section 21 serves as an intermediate transition structure connecting the opening section 20 and the cover plate body 1, thereby extending the heat conduction path length between the opening section 20 and the cover plate body 1. Specifically, when the cover plate body 1 is welded and encapsulated with the battery casing 1001, the high temperature generated during welding must pass through the buffer section 21 before being transferred to the opening section 20. The buffer section 21 effectively blocks and disperses welding heat and stress, reducing the impact on the opening section 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.

[0052] Please refer to Figure 5 The opening section 20 is provided with a bursting section 200 and a reinforcing section 22, which are spaced apart. This creates a certain gap between the bursting section 200 and the reinforcing section 22. This spacing effectively reduces mutual interference between the bursting section 200 and the reinforcing section 22 during molding, thereby reducing the possibility of deformation of the bursting section 200 or the reinforcing section 22 and improving the molding rate of the explosion-proof valve.

[0053] 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.

[0054] In some embodiments, refer to Figure 5In the specific embodiment shown, the reinforcing part 22 is located in the central region of the opening part 20. This is equivalent to localized strength reinforcement in the area of ​​the opening part 20 most prone to deformation, thus improving the bending resistance of the opening part 20 under pressure load. 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 be one or more.

[0055] 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 molding process of the protruding structure includes, but is not limited to, stamping, extrusion, and injection molding.

[0056] In some embodiments, refer to Figure 5 and Figure 6 In the specific embodiment shown, the reinforcing part 22 is a protruding structure that protrudes towards both the first surface 10 and the second surface 11.

[0057] Along the thickness direction of the cover plate body 1, the distance between the end of the explosion-proof valve 2 away from the first surface 10 and the surface of the opening part 20 is A, and along the thickness direction of the cover plate body 1, the distance between the end of the reinforcing part 22 away from the first surface 10 and the surface of the opening part 20 is A1; satisfying: 0≤A1≤A. Therefore, the height of the reinforcing part 22 protrusion will not exceed that of the explosion-proof valve 2, ensuring that the reinforcing part 22, as a local reinforcing structure, will not occupy additional internal space of the battery pack due to excessive protrusion. Simultaneously, it strengthens the local rigidity of the opening part 20, enabling it to effectively resist thermal stress and structural deformation caused by heat conduction in subsequent processes (such as welding the housing 1001 to the cover plate body 1), making the explosion-proof valve 2 less prone to cracking. This ensures the structural integrity of the explosion section 200, guarantees the preset opening pressure and explosion reliability of the explosion-proof valve 2, and improves the yield rate of battery production.

[0058] It should be noted that when A1=0, that is, the distance between the reinforcing part 22 and the opening part 20 is 0, the reinforcing part 22 does not protrude from the surface of the opening part 20. In this embodiment, the reinforcing part 22 can protrude toward the second surface 11 to improve the structural strength of the opening part 20.

[0059] 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 12 or Figure 15 As shown.

[0060] Please refer to Figure 6 , Figure 8 as well as Figure 9 In some embodiments, the reinforcing part 22 has a solid structure. That is, the interior of the reinforcing part 22 is filled with solid material, and the deformation resistance of the opening part 20 is increased by locally thickening it.

[0061] Along the thickness direction of the cover plate body 1, the thickness of the reinforcing part 22 is B. Along the thickness direction of the cover plate body 1, the thickness of the opening part 20 is B1. This satisfies the condition: 1 ≤ B / B1 ≤ 10. For example, B / B1 can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc., or any value between any two of the above. Therefore, by limiting the ratio of the thickness of the solid reinforcing part 22 to the thickness of the opening part 20 to the range of 1 to 10, the reinforcing part 22 has sufficient thickness to provide local reinforcement, effectively resisting external stress and preventing deformation of the explosion-proof valve, while also facilitating the molding of the explosion-proof valve and improving the molding yield. When B / B1 is less than 1, the thickness of the reinforcing part 22 is too thin, leading to difficulties in molding the reinforcing part 22 and a low molding yield of the explosion-proof valve. When B / B1 is greater than 10, the reinforcing part 22 is too thick, leading to excessive material accumulation, difficulties in stamping and extrusion, and a low molding yield of the explosion-proof valve.

[0062] Please refer to Figure 10 In other embodiments, the reinforcing portion 22 has a hollow structure and protrudes toward the first surface 10 and / or the second surface 11 of the cover plate body 1. It is 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, a protrusion protruding only toward the second surface 11, or a protrusion protruding toward both the first surface 10 and the second surface 11. For example, see... Figure 10 In the specific embodiment shown, the reinforcing part 22 is a protruding structure that bulges towards the first surface 10. The interior of the reinforcing part 22 is hollow, and its shape is similar to an upwardly bulging dome-shaped structure. The hollow structure of the reinforcing part 22 can improve the local stiffness of the opening part 20, and because the interior of the reinforcing part 22 is hollow, it can achieve a lighter weight and improve the energy density of the battery cell while keeping the same external dimensions.

[0063] Please refer to Figure 8On a plane perpendicular to the thickness direction of the cover plate body 1, the distance T between the edge of the reinforcing part 22 and the bursting section 200 satisfies: T ≥ 3mm. For example, T can be 3mm, 4mm, 5mm, 6mm, 7mm, etc., or any value between any two of the above values. Thus, for the hollow reinforcing part 22, by further limiting the minimum distance between the reinforcing part 22 and the bursting section 200 to not less than 3mm, the problem of forming difficulties is avoided when processing the bursting section 200 or the reinforcing part 22. If T is less than 3mm, it will affect the bursting section 200 (e.g., deformation) when stamping the reinforcing part 22, thereby affecting the opening pressure of the opening part 20 and reducing the yield of the explosion-proof valve 2.

[0064] Please refer to Figure 11 In some embodiments, the 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. This creates multiple bent structures in the buffer section 21, increasing the heat conduction path for welding heat and ensuring the stability and reliability of the explosion-proof valve 2. 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, allowing pressure to be quickly applied to the explosion-proof valve 2 via the cavity 215 when the pressure inside the housing 1001 increases. The first buffer section 210, the third buffer section 212, the fourth buffer section 213, the bending section 214, and the second buffer section 211 are integrally formed structures.

[0065] Please refer to Figure 11The 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.

[0066] Reference Figure 7 and Figure 11The 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.

[0067] 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.

[0068] Please refer to Figure 7 In some embodiments, the cover plate assembly 1000 further includes a pole post 3 for electrical connection with the electrode tab of the battery cell, and 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 means of riveting, welding or by means of sealing clips.

[0069] 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. The second electrical connection surface 31 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.

[0070] Please refer to Figure 7Along the thickness direction of the cover plate body 1, the distance between the first electrical connection surface 30 and the first surface 10 is A4, the thickness of the cover plate body 1 is A3, and the distance between the end of the explosion-proof valve 2 away from the first surface 10 and the first surface 10 is A2, satisfying: -0.5×A3≤A2≤A4. By satisfying the above relationship, it can be ensured that 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.

[0071] Specifically, if A2 is less than -0.5×A3, it means that the explosion-proof valve 2 is recessed below the first surface 10 of the cover plate body 1, which makes material flow difficult during the stamping process, making it difficult to form the explosion-proof valve 2. If A2 is greater than A4, 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.

[0072] Please refer to Figure 8 In some embodiments, the thickness of the opening portion 20 is B1, satisfying the condition: 0.15mm ≤ B1 ≤ 0.4mm. For example, B1 can take values ​​of 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, etc., or any value between any two of the above values. When B1 is less than 0.15mm, the structural strength of the opening portion 20 is insufficient, and it is prone to deformation under the influence of welding heat, resulting in reduced reliability. When B1 is greater than 0.4mm, the structural strength of the opening portion 20 is too high, which may cause the explosion-proof valve 2 to be difficult to open when the internal pressure of the battery cell reaches the threshold, thus losing its safety protection function. By controlling B within the above range, it can be ensured that the opening portion 20 has appropriate strength, is not easily deformed, and can maintain a stable opening pressure threshold, allowing it to open normally when needed.

[0073] Please refer to Figures 12 to 15 In some embodiments, on a plane perpendicular to the thickness direction of the cover plate body 1 and along the width direction of the cover plate body 1, the width of the orthographic projection of the explosion-proof valve 2 is C, and the width of the orthographic projection of the bent section 214 of the explosion-proof valve 2 is C1, satisfying: 0.7 ≤ C1 / C ≤ 1.3. For example, the ratio of C1 / C can be: 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, etc., or any value between any two of the above values. This can improve the molding yield of the explosion-proof valve and ensure that the opening pressure of the explosion-proof valve meets the requirements.

[0074] Specifically, when C1 / C is less than 0.7, the area enclosed by the bending section 214 is too small, affecting the molding of the explosion-proof valve. The area of ​​the opening part 20 is too small, making the explosion-proof valve unable to meet the opening pressure requirements. When C1 / C is greater than 1.3, the area enclosed by the bending section 214 is too large, making it difficult to mold the buffer part 21, which in turn affects the molding of the explosion-proof valve.

[0075] Please refer to Figure 13 In some embodiments, on a plane perpendicular to the thickness direction of the cover plate body 1, along the length direction of the cover plate body 1, the maximum length of the orthographic projection of the explosion-proof valve 2 is D, and the maximum length of the orthographic projection of the bent section 214 of the explosion-proof valve 2 is D1, satisfying: 0.7 ≤ D1 / D ≤ 1.3. For example, the ratio of D1 / D can be: 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, etc., or any value between any two of the above values. This can improve the molding yield of the explosion-proof valve and ensure that the opening pressure of the explosion-proof valve meets the requirements.

[0076] Specifically, when D1 / D is less than 0.7, the area enclosed by the bending section 214 is too small, affecting the molding of the explosion-proof valve. The area of ​​the opening part 20 is too small, making the explosion-proof valve unable to meet the opening pressure requirements. When D1 / D is greater than 1.3, the area enclosed by the bending section 214 is too large, making it difficult to mold the buffer part 21, which in turn affects the molding of the explosion-proof valve.

[0077] In some embodiments, such as Figures 12 to 14 As shown, when the explosion-proof valve 2 is circular, it satisfies: 0.8 ≤ C1 / C ≤ 1.2. For example, the ratio of C1 / C can be 0.8, 0.9, 1.0, 1.1, 1.2, etc., or any value between any two of the above values. It also satisfies: 0.8 ≤ D1 / D ≤ 1.2. For example, the ratio of D1 / D can be 0.8, 0.9, 1.0, 1.1, 1.2, etc.

[0078] In some embodiments, such as Figure 15 As shown, when the explosion-proof valve 2 is oblong, it satisfies: 0.7 ≤ C1 / C ≤ 1.3. For example, the ratio of C1 / C can be 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, etc., or any value between any two of the above values. It also satisfies: 0.7 ≤ D1 / D ≤ 1.3. For example, the ratio of D1 / D can be 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, etc., or any value between any two of the above values.

[0079] The technical solution of this application will be described below with reference to the embodiments. In order to further verify the influence of the C1 / C ratio on the forming effect of the explosion-proof valve when the explosion-proof valve 2 is circular, this application studied the stamping forming experiment of the explosion-proof valve under different ratios. The specific experimental parameters and results are shown in Table 1.

[0080] Table 1 As shown in Table 1, in Example 1, C1 is 10mm and C is 20mm, resulting in a C1 / C ratio of 0.5. This C1 / C ratio is too small, failing to meet the requirement of 0.8 ≤ C1 / C ≤ 1.2. This ratio will affect the size design of the explosion-proof valve during the molding process and is not recommended. In Examples 2-10, the C1 / C ratio is within the range of 0.8-1.2, thus satisfying the requirement of 0.8 ≤ C1 / C ≤ 1.2. The molding yield of the explosion-proof valve is ≥99.88%, and the opening pressure of the explosion-proof valve meets the requirements. In Example 11, C1 is 30mm and C is 20mm, resulting in a C1 / C ratio of 1.5. This C1 / C ratio is too large, failing to meet the requirement of 0.8 ≤ C1 / C ≤ 1.2. This ratio will affect the molding of the explosion-proof valve during stamping and is not recommended. In Example 12, C1 is 10mm and C is 10mm, so the ratio of C1 / C is 1, satisfying 0.8 ≤ C1 / C ≤ 1.2. The results show that the forming yield of the explosion-proof valve during stamping is ≥99.88%, and the opening pressure of the explosion-proof valve meets the requirements. In Example 13, C1 is 15mm and C is 15mm, so the ratio of C1 / C is 1, satisfying 0.8 ≤ C1 / C ≤ 1.2. The results show that the forming yield of the explosion-proof valve during stamping is ≥99.88%, and the opening pressure of the explosion-proof valve meets the requirements. In Example 14, C1 is 40mm and C is 40mm, so the ratio of C1 / C is 1, satisfying 0.8 ≤ C1 / C ≤ 1.2. The results show that the forming yield of the explosion-proof valve during stamping is ≥99.88%, and the opening pressure of the explosion-proof valve meets the requirements. In Example 15, C1 is 60mm and C is 60mm, so the ratio of C1 / C is 1.5, satisfying 0.8≤C1 / C≤1.2. As a result, when stamping the explosion-proof valve, the forming yield is ≥99.88%, and the opening pressure of the explosion-proof valve meets the requirements.

[0081] To further verify the influence of the D1 / D ratio on the forming effect of the explosion-proof valve 2 when it is circular, this application conducted a stamping forming experiment on the explosion-proof valve 2 under different ratios. The specific experimental parameters and results are shown in Table 2.

[0082] Table 2 As shown in Table 2, in Example 1, D1 is 10mm and D is 20mm, resulting in a D1 / D ratio of 0.5, which does not satisfy the requirement of 0.8 ≤ D1 / D ≤ 1.2. This will affect the design of the explosion-proof valve size, and its use is not recommended. In Examples 2-10, D1 is 16mm-24mm and D is 20mm, so the D1 / D ratio ranges from 0.8 to 1.2, satisfying the requirement of 0.8 ≤ D1 / D ≤ 1.2. The results show that when stamping the explosion-proof valve, the forming yield is ≥99.88%, and the opening pressure of the explosion-proof valve meets the requirements. In Example 11, D1 is 30mm and D is 20mm, resulting in a D1 / D ratio of 1.5, which is too large and does not satisfy the requirement of 0.8 ≤ D1 / D ≤ 1.2. The results show that stamping the explosion-proof valve will affect its forming, and its use is not recommended. In Example 12, D1 is 10mm and D is 10mm, so the ratio of D1 / D is 1, satisfying 0.8 ≤ D1 / D ≤ 1.2. The results show that the forming yield of the explosion-proof valve during stamping is ≥99.88%, and the opening pressure of the explosion-proof valve meets the requirements. In Example 13, D1 is 15mm and D is 15mm, so the ratio of D1 / D is 1, satisfying 0.8 ≤ D1 / D ≤ 1.2. The results show that the forming yield of the explosion-proof valve during stamping is ≥99.88%, and the opening pressure of the explosion-proof valve meets the requirements. In Example 14, D1 is 40mm and D is 40mm, so the ratio of D1 / D is 1, satisfying 0.8 ≤ D1 / D ≤ 1.2. The results show that the forming yield of the explosion-proof valve during stamping is ≥99.88%, and the opening pressure of the explosion-proof valve meets the requirements. In Example 15, D1 is 60mm and D is 60mm, so the ratio of D1 / D is 1.5, satisfying 0.8≤D1 / D≤1.2. The results show that when stamping the explosion-proof valve, the forming yield is ≥99.88%, and the opening pressure of the explosion-proof valve meets the requirements.

[0083] To further verify the effect of the C1 / C ratio on the forming effect of the explosion-proof valve when it is waist-shaped, this study conducted stamping forming experiments on the explosion-proof valve at different ratios. The specific experimental parameters and results are shown in Table 3.

[0084] Table 3 Table 3 shows that in Example 1, C1 is 10mm and C is 20mm, resulting in a C1 / C ratio of 0.5. This C1 / C ratio is too small, failing to meet the requirement of 0.7 ≤ C1 / C ≤ 1.3. Result: This affects the design of the explosion-proof valve size and is not recommended. In Examples 2-10, C1 is 16mm-24mm and C is 20mm, resulting in a C1 / C ratio range of 0.8-1.2, satisfying the requirement of 0.7 ≤ C1 / C ≤ 1.3. Results show that the forming yield of the explosion-proof valve during stamping is ≥99.88%, and the opening pressure of the explosion-proof valve meets the requirements. In Example 11, C1 is 30mm and C is 20mm, resulting in a C1 / C ratio of 1.5. This C1 / C ratio is too large, failing to meet the requirement of 0.7 ≤ C1 / C ≤ 1.3. Result: This affects the forming of the explosion-proof valve and is not recommended. In Example 12, C1 is 10mm and C is 10mm, so the ratio of C1 / C is 1, satisfying 0.7 ≤ C1 / C ≤ 1.3. The results show that the forming yield of the explosion-proof valve during stamping is ≥99.88%, and the opening pressure of the explosion-proof valve meets the requirements. In Example 13, C1 is 15mm and C is 15mm, so the ratio of C1 / C is 1, satisfying 0.7 ≤ C1 / C ≤ 1.3. The results show that the forming yield of the explosion-proof valve during stamping is ≥99.88%, and the opening pressure of the explosion-proof valve meets the requirements. In Example 14, C1 is 40mm and C is 40mm, so the ratio of C1 / C is 1, satisfying 0.7 ≤ C1 / C ≤ 1.3. The results show that the forming yield of the explosion-proof valve during stamping is ≥99.88%, and the opening pressure of the explosion-proof valve meets the requirements. In Example 15, C1 is 60mm and C is 60mm, so the ratio of C1 / C is 1.5, satisfying 0.7≤C1 / C≤1.3. The results show that when stamping the explosion-proof valve, the forming yield is ≥99.88%, and the opening pressure of the explosion-proof valve meets the requirements.

[0085] To further verify the effect of the D1 / D ratio on the forming effect of the explosion-proof valve, this application conducted stamping forming experiments on the explosion-proof valve under different ratios. The specific experimental parameters and results are shown in Table 4.

[0086] Table 4 As shown in Table 4, in Example 1, D1 is 15mm and D is 30mm, resulting in a D1 / D ratio of 0.5. This ratio is too small, failing to meet the requirement of 0.7 ≤ D1 / D ≤ 1.3. The results indicate that this affects the design of the explosion-proof valve size and is not recommended. In Examples 2-10, D1 ranges from 21mm to 39mm, and D is 30mm, resulting in a D1 / D ratio range of 0.7 to 1.3, thus satisfying the requirement of 0.7 ≤ D1 / D ≤ 1.3. The results show a molding yield ≥ 99.88%, and the explosion-proof valve opening pressure meets the requirements. In Example 11, D1 is 50mm and D is 30mm, resulting in a D1 / D ratio of 1.67. This ratio is too large, failing to meet the requirement of 0.7 ≤ D1 / D ≤ 1.3. This affects the molding of the explosion-proof valve and is not recommended. In Example 12, D1 is 10mm and D is 10mm, so the ratio of D1 / D is 1, satisfying 0.7 ≤ D1 / D ≤ 1.3. The results show a molding yield ≥ 99.88%, and the explosion-proof valve opening pressure meets the requirements. In Example 13, D1 is 15mm and D is 15mm, so the ratio of D1 / D is 1, satisfying 0.7 ≤ D1 / D ≤ 1.3. The results show a molding yield ≥ 99.88%, and the explosion-proof valve opening pressure meets the requirements. In Example 14, D1 is 40mm and D is 40mm, so the ratio of D1 / D is 1, satisfying 0.7 ≤ D1 / D ≤ 1.3. The results show a molding yield ≥ 99.88%, and the explosion-proof valve opening pressure meets the requirements. In Example 15, D1 is 60mm and D is 60mm, so the ratio of D1 / D is 1.5, satisfying 0.7≤D1 / D≤1.3. The results show that the molding yield is ≥99.88%, and the explosion-proof valve opening pressure meets the requirements.

[0087] 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 forming effect of 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 5.

[0088] Table 5 As shown in Table 5, 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 ≥99.65% when stamping the explosion-proof valve. In Example 10, the included angle α is 210°, 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.

[0089] 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 test of the explosion-proof valve 2 under different sizes A3, A2 and A4. The specific experimental parameters and results are shown in Table 6.

[0090] Table 6 As shown in Table 6, in Example 1, A3 is 2mm, A4 is 3.2mm, and A2 is -1.5mm. The value of A2 is too small, not meeting the range of -0.5×A3≤A2≤A4. During the stamping of explosion-proof valve 2, forming is difficult, and the defect rate is ≥5.6%. In Examples 2-13, A3 is 2mm, A4 is 3.2mm, and A2 ranges from -1mm to 3.2mm, satisfying the range of -0.5×A3≤A2≤A4. Results: 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, A3 is 2mm, A4 is 3.2mm, and A2 is 3.6mm. The value of A2 is too large, not meeting the range of -0.5×A3≤A2≤A4. Result: During the stamping of the explosion-proof valve, the explosion-proof valve 2 was higher than the surface of the pole post 3, which affected the space utilization of the battery cell.

[0091] In Example 15, A3 is 1.5mm, A4 is 3.2mm, and A2 is -0.5mm, satisfying -0.5×A3≤A2≤A4. In Example 16, A3 is 3mm, A4 is 3.2mm, and A2 is 0, meaning the end of the explosion-proof valve 2 furthest from the first surface 10 is flush with it, satisfying -0.5×A3≤A2≤A4. In Example 17, A3 is 2mm, A4 is 5mm, and A2 is 0mm, meaning the end of the explosion-proof valve 2 furthest from the first surface 10 is flush with it, satisfying -0.5×A3≤A2≤A4. In Example 18, A3 is 2mm, A4 is 2.2mm, and A2 is 0mm, meaning the end of the explosion-proof valve 2 furthest from the first surface 10 is flush with it, satisfying -0.5×A3≤A2≤A4. In Example 19, A3 is 2mm, A4 is 1mm, and A2 is 0mm, meaning the end of the explosion-proof valve 2 furthest from the first surface 10 is flush with it, satisfying -0.5×A3≤A2≤A4. In Example 20, A3 is 2mm, A4 is 0.2mm, and A2 is 0mm, meaning the end of the explosion-proof valve 2 furthest from the first surface 10 is flush with it, satisfying -0.5×A3≤A2≤A4. 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×A3≤A2≤A4 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.

[0092] To further verify the influence of the ratio of the thickness B of the reinforcing part 22 to the thickness B1 of the opening part 20 on the forming quality of the explosion-proof valve 2 when the reinforcing part 22 is a solid structure, this application studied the stamping test of the explosion-proof valve with the reinforcing part 22 and the opening part 20 selected with different thicknesses. The specific experimental parameters and results are shown in Table 7.

[0093] Table 7 As shown in Table 7, in Example 1, B1 is 0.25mm, B is 0.15mm, and B / B1 is 0.6. B / B1 is too small, failing to satisfy the condition 1≤B / B1≤10. This results in difficulty in forming the explosion-proof valve during stamping, with a defect rate ≥5.9%. In Examples 2-11, B1 is 0.25mm, B is 0.15mm-2.5mm, and B / B1 is 1-10, satisfying the condition 1≤B / B1≤10. As a result, the forming yield of the explosion-proof valve during stamping is ≥99.8%, and the opening pressure of the explosion-proof valve meets the requirements. In Example 12, B1 is 0.25mm, B is 4mm, and B / B1 is 16. This condition is too large, failing to satisfy the condition 1≤B / B1≤10. As a result, during the stamping of the explosion-proof valve, the stamping and extrusion process was difficult, and the defect rate was ≥8.65%. In Example 13, B1 was 0.15mm, B was 0.5mm, and B / B1 was 3.33. This satisfies the condition: 1≤B / B1≤10. As a result, during the stamping of the explosion-proof valve, the forming yield was ≥99.84%, and the opening pressure of the explosion-proof valve met the requirements. In Example 14, B1 was 0.4mm, B was 1mm, and B / B1 was 2.5. This satisfies the condition: 1≤B / B1≤10. As a result, during the stamping of the explosion-proof valve, the forming yield was ≥99.84%, and the opening pressure of the explosion-proof valve met the requirements.

[0094] 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 has a first surface and a second surface, the first surface and the second surface being 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 away from the opening part is connected to the cover plate body; the opening part is provided with a bursting section and a reinforcing section, the bursting section and the reinforcing section are arranged at intervals, and the reinforcing section has a protruding structure protruding towards the first surface and / or the second surface; Along the thickness direction of the cover plate body, the distance between the end of the explosion-proof valve away from the first surface and the surface of the opening part is A, and along the thickness direction of the cover plate body, the distance between the end of the reinforcing part away from the first surface and the surface of the opening part is A1; satisfying: 0≤A1≤A.

2. The cover plate assembly according to claim 1, characterized in that, The reinforcing part is a solid structure, and its thickness along the thickness direction of the cover plate body is B; the thickness of the opening part is B1; satisfying: 1≤B / B1≤10; and / or, The thickness of the opening portion is B1, which satisfies the condition: 0.15mm≤B1≤0.4mm.

3. The cover plate assembly according to claim 1, characterized in that, The reinforcing part has a hollow structure and protrudes toward the first surface and / or the second surface of the cover plate body; On a plane perpendicular to the thickness direction of the cover plate body, the distance T between the edge of the reinforcing part and the bursting section satisfies: T≥3mm.

4. The cover plate assembly according to any one of claims 1-3, characterized in that, The buffer portion includes at least a first buffer section and a second buffer section. The second buffer section is connected to the opening portion. The second buffer section has a first wall surface. 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°.

5. The cover plate assembly according to claim 4, 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.

6. The cover plate assembly according to claim 5, characterized in that, 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, and along the width direction of the cover plate body, the width of the orthographic projection of the explosion-proof valve is C, and the width of the orthographic projection of the bent section of the explosion-proof valve is C1, satisfying: 0.7 ≤ C1 / C ≤ 1.3; and / or, On a plane perpendicular to the thickness direction of the cover plate body, along the length direction of the cover plate body, the maximum length of the orthographic projection of the explosion-proof valve is D, and the maximum length of the orthographic projection of the bent section of the explosion-proof valve is D1, satisfying: 0.7≤D1 / D≤1.

3.

8. The cover plate assembly according to claim 1, characterized in that, Also includes: An electrode post is disposed on the cover plate body. At least a portion of the electrode 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 A4, the thickness of the cover plate body is A3, and the distance between the end of the explosion-proof valve away from the first surface and the first surface is A2, satisfying: -0.5×A3≤A2≤A4.

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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