Cover plate assembly and battery cell

Abstract

The invention relates to a cover plate assembly and a battery cell, and relates to the technical field of batteries, the cover plate assembly comprises a cover plate and an explosion-proof valve, and the cover plate comprises a first side and a second side which are distributed along a first direction; the cover plate is provided with an anti-explosion hole penetrating through the first side and the second side; the anti-explosion hole comprises a first hole section and a second hole section which are distributed in the first direction, the second hole section is communicated with the first hole section, and the end, away from the second hole section, of the first hole section penetrates through the second side; wherein the first direction represents the thickness direction of the cover plate; and the anti-explosion valve is arranged in the second hole section. According to the cover plate assembly and the battery cell, the problem that the explosion-proof valve is easy to interfere with the lower plastic can be solved, and the explosion-proof valve is prevented from being damaged by the lower plastic.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a cover plate assembly and a battery cell. Background Technology

[0002] Battery cell covers typically have explosion-proof holes for installing explosion-proof valves. These valves open when the internal pressure of the battery cell becomes too high, allowing for timely release of gas. However, in some related technologies, the explosion-proof valve is installed within the explosion-proof hole. This can easily interfere with the lower plastic sealant on the inner side of the cover (the side closest to the electrode assembly), potentially causing damage to the valve. Summary of the Invention

[0003] To address the aforementioned technical problems, embodiments of this application provide a cover plate assembly and a battery cell, which can improve the problem of easy interference between the explosion-proof valve and the lower plastic, and prevent the explosion-proof valve from being damaged by the lower plastic.

[0004] In a first aspect, a cover plate assembly is provided, comprising: A cover plate includes a first side and a second side distributed along a first direction; the cover plate is provided with an explosion-proof hole penetrating the first side and the second side; the explosion-proof hole includes a first hole segment and a second hole segment distributed along the first direction, the second hole segment communicating with the first hole segment, and the end of the first hole segment away from the second hole segment penetrating the second side; wherein, the first direction characterizes the thickness direction of the cover plate; An explosion-proof valve is installed in the second orifice section.

[0005] According to a first aspect of this application, the projection of the inner wall of the second hole segment onto the reference plane along the first direction is located inside the projection of the inner wall of the first hole segment onto the reference plane along the first direction, so that a first step surface is formed between the first hole segment and the second hole segment; wherein, the reference plane represents a plane parallel to the first side and / or the second side.

[0006] According to a first aspect of this application, the width of the first step surface is T1, wherein T1 satisfies: 0.5mm≤T1≤3mm; and / or, the distance between the first step surface (1133) and the second side (112) along the first direction is L, wherein L satisfies: L≥0.2mm.

[0007] According to a first aspect of this application, the first side includes a reference wall and a protruding wall, the protruding wall protruding relative to the reference wall along the first direction, and the explosion-proof hole penetrating the protruding wall.

[0008] According to a first aspect of this application, the second hole segment includes a first segment, a second segment, and a third segment that communicate along the first direction, the first segment communicating with the first hole segment, and the third segment penetrating the protruding wall at one end away from the second segment; Wherein, the projection of the inner wall of the second segment along the first direction onto the reference surface is located inside the projection of the inner wall of the first segment along the first direction onto the reference surface, so that a second step surface is formed between the first segment and the second segment, the explosion-proof valve is disposed in the first segment, and the explosion-proof valve abuts against the second step surface; wherein, the reference surface represents a plane parallel to the first side and / or the second side.

[0009] According to a first aspect of this application, the width of the second step surface is T2, wherein T2 satisfies: 0.3mm ≤ T2 ≤ 2.5mm.

[0010] According to a first aspect of this application, the projection of the inner wall of the second segment onto the reference plane along the first direction is located inside the projection of the inner wall of the third segment onto the reference plane along the first direction, so that a third step surface is formed between the second segment and the third segment. The cover plate assembly also includes: A protective film is disposed within the third segment, and the protective film abuts against the third step surface.

[0011] According to a first aspect of this application, the width of the third step surface is T3, and T3 satisfies: 0.3mm ≤ T3 ≤ 2.5mm.

[0012] According to a first aspect of this application, the explosion-proof valve is provided with a groove, and the distance between the projection of the inner wall of the groove along the first direction onto the reference surface and the projection of the inner wall of the second segment along the first direction onto the reference surface is E, wherein E satisfies: 0.1mm≤E≤3mm.

[0013] According to a first aspect of this application, the projection of the inner wall of the second hole segment onto the reference plane along the first direction is located inside the projection of the inner wall of the first hole segment onto the reference plane along the first direction, so that a first step surface is formed between the first hole segment and the second hole segment; wherein, the reference plane represents a plane parallel to the first side and / or the second side; the distance between the first step surface and the reference wall along the first direction is B, wherein B satisfies: B≥0.7mm; and / or, The projection of the edge of the protruding wall along the first direction onto the reference plane is located inside the projection of the inner wall of the first hole segment along the first direction onto the reference plane; wherein, the reference plane represents a plane parallel to the first side and / or the second side; the distance between the projection of the edge of the protruding wall along the first direction onto the reference plane and the projection of the inner wall of the first hole segment along the first direction onto the reference plane is F, wherein F satisfies: 0.05mm ≤ F ≤ 2mm; and / or, The cover plate assembly also includes: An electrode assembly is disposed on the cover plate, and the top end of the electrode assembly protrudes relative to the reference wall along the first direction; wherein, the distance between the top end of the electrode assembly and the reference wall along the first direction is H, and the distance between the protruding wall and the reference wall along the first direction is A, wherein A and H satisfy: 0.2mm≤A≤H.

[0014] Secondly, a battery cell is also provided, including: The casing has an opening; The pole assembly is located within the housing; As described in the previous embodiment, the cover plate assembly is located at one end of the electrode assembly, and the cover plate is connected to the housing to close the opening.

[0015] The cover plate assembly and battery cell provided in this application embodiment have an explosion-proof valve disposed in the second hole section. Since a first hole section is reserved between the second hole section and the second side, the explosion-proof valve is separated from the second side by the first hole section. The first hole section can separate the explosion-proof valve from the lower plastic set on the second side. In this way, the problem of easy interference between the explosion-proof valve and the lower plastic can be effectively improved, and the explosion-proof valve is prevented from being damaged by the lower plastic. Attached Figure Description

[0016] The above and other objects, features, and advantages of this application will become more apparent from the more detailed description of the embodiments of this application in conjunction with the accompanying drawings. The drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the embodiments of this application to explain this application and do not constitute a limitation thereof. In the drawings, the same reference numerals generally represent the same components or steps.

[0017] Figure 1 This is a schematic diagram of the structure of a cover plate assembly provided for an exemplary embodiment of this application.

[0018] Figure 2 An exploded view of a cover plate assembly provided for an exemplary embodiment of this application.

[0019] Figure 3 A cross-sectional view of a cover plate assembly provided for an exemplary embodiment of this application.

[0020] Figure 4 for Figure 3 Enlarged schematic diagram of point M in the middle.

[0021] Reference numerals: 100-Cover plate assembly; 110-Cover plate; 111-First side; 1111-Reference wall; 1112-Protruding wall; 112-Second side; 113-Explosion-proof hole; 1131-First hole segment; 1132-Second hole segment; 11321-First section; 11322-Second section; 11323-Third section; 11324-Second step surface; 11325-Third step surface; 1133-First step surface; 120-Explosion-proof valve; 121-Score groove; 130-Protective film; 140-Pole post assembly; 150-Lower plastic. Detailed Implementation

[0022] Hereinafter, exemplary embodiments according to this application will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments of this application. It should be understood that this application is not limited to the exemplary embodiments described herein.

[0023] Figure 1 This is a schematic diagram of the structure of a cover plate assembly provided for an exemplary embodiment of this application. Figure 1 As shown, the battery cell provided in this embodiment may include a housing, an electrode assembly, and a cover assembly 100. The housing has an opening, through which the electrode assembly can be fitted into the housing. The cover assembly 100 is disposed at one end of the electrode assembly and can be connected to the housing. The cover assembly 100 can close the opening. The cover assembly 100 and the housing can prevent foreign objects from entering the electrode assembly, thus protecting the electrode assembly.

[0024] like Figure 1 As shown, the cover plate assembly 100 provided in this application embodiment may include a cover plate 110, which can be used to directly connect to the aforementioned housing to close the opening and prevent foreign objects from entering the electrode assembly through the opening.

[0025] Figure 2 An exploded view of a cover plate assembly provided for an exemplary embodiment of this application. Figure 3 A cross-sectional view of a cover plate assembly provided for an exemplary embodiment of this application. Figure 4 for Figure 3 An enlarged diagram of point M in the middle. (See diagram below.) Figures 2 to 4As shown, the cover assembly 100 may further include an explosion-proof valve 120. The cover 110 is provided with an explosion-proof hole 113, and the explosion-proof valve 120 is disposed within the explosion-proof hole 113. In practical applications, when the battery cell experiences abnormal conditions (such as overcharging, over-discharging, short circuit, etc.), a large amount of gas is generated inside the casing, increasing the gas pressure. When the gas pressure increases to the pressure threshold, the explosion-proof valve 120 can open to promptly release the gas inside the casing, reducing the gas pressure and effectively preventing safety accidents such as combustion and explosion caused by excessive internal gas pressure.

[0026] like Figure 3 and Figure 4 As shown, the cover plate 110 may include a direction along the first direction (which can be understood as the thickness direction of the cover plate 110, see reference for details). Figure 3 and Figure 4 The first side 111 and the second side 112 are distributed in the Z-axis direction. The aforementioned explosion-proof hole 113 can penetrate the first side 111 and the second side 112. In this way, after the explosion-proof valve 120 is opened, the gas can be discharged to the outside of the cover plate 110 (the side of the cover plate 110 away from the electrode group) through the explosion-proof valve 120 and the explosion-proof hole 113.

[0027] It should be noted that after the cover plate 110 is connected to the aforementioned housing, the first side 111 can be considered as the side of the cover plate 110 away from the electrode group, and the second side 112 can be considered as the side closer to the electrode group.

[0028] like Figures 2 to 4 As shown, the second side 112 is provided with a lower plastic 150. The lower plastic 150 can be used to prevent the second side 112 from directly contacting the electrode assembly, thus avoiding a short circuit between the electrode assembly and the cover plate 110. In related technologies, after the explosion-proof valve 120 is installed into the explosion-proof hole 113, the bottom of the explosion-proof valve 120 is prone to interference with the lower plastic 150, which can easily cause damage to the explosion-proof valve 120.

[0029] Therefore, such as Figure 3 and Figure 4 As shown, the explosion-proof hole 113 may include a first direction (reference) Figure 3 and Figure 4 The first hole segment 1131 and the second hole segment 1132 are distributed in the Z-axis direction. The second hole segment 1132 is connected to the first hole segment 1131. The end of the first hole segment 1131 away from the second hole segment 1132 passes through the second side 112 (that is, the first hole segment 1131 is located between the second hole segment 1132 and the second side 112). The explosion-proof valve 120 is located in the second hole segment 1132.

[0030] It should be understood that when the explosion-proof valve 120 is located in the second hole section 1132, since the first hole section 1131 is reserved between the second hole section 1132 and the second side 112, the explosion-proof valve 120 and the second side 112 are separated by the first hole section 1131. The first hole section 1131 can separate the explosion-proof valve 120 from the lower plastic 150 provided on the second side 112, which can effectively improve the problem that the explosion-proof valve 120 is prone to interference with the lower plastic 150 and avoid the explosion-proof valve 120 being damaged by the lower plastic 150.

[0031] In one embodiment, the first hole segment 1131 can be a circular hole segment, an elliptical hole segment, a rectangular hole segment, etc. The second hole segment 1132 can be a circular hole segment, an elliptical hole segment, a rectangular hole segment, etc.

[0032] In one embodiment, the first hole segment 1131 and the second hole segment 1132 may have the same or different shapes.

[0033] like Figure 4 As shown, the inner wall of the second hole segment 1132 is along the first direction (reference). Figure 4 The projection of the Z-axis direction in the reference plane (which can be understood as a plane parallel to the first side 111 and / or the second side 112) onto the reference plane is located inside the projection of the inner wall of the first hole segment 1131 onto the reference plane along the first direction, which can make a first step surface 1133 be formed between the first hole segment 1131 and the second hole segment 1132.

[0034] It should be noted that after the explosion-proof valve 120 is installed into the second orifice 1132, the outer wall of the explosion-proof valve 120 needs to be welded to the inner wall of the second orifice 1132 (that is, the explosion-proof valve 120 needs to be welded to the cover plate 110). Therefore, setting the projection of the inner wall of the second orifice 1132 along the first direction on the reference plane inside the projection of the inner wall of the first orifice 1131 along the first direction on the reference plane is beneficial for the welding process. During the welding process, the welding head can extend into the second orifice 1132 through the first orifice 1131, which facilitates the welding head to weld the outer wall of the explosion-proof valve 120 to the inner wall of the second orifice 1132, thereby improving the welding efficiency.

[0035] Furthermore, during the welding process, the first step surface 1133 formed between the first hole section 1131 and the second hole section 1132 can facilitate the welding head to simultaneously contact the outer wall of the explosion-proof valve 120 and the inner wall of the second hole section 1132, and weld marks can be formed on the first step surface 1133. In this way, the welding quality between the outer wall of the explosion-proof valve 120 and the inner wall of the second hole section 1132 can be improved.

[0036] In one embodiment, the first hole segment 1131 and the second hole segment 1132 are both circular hole segments, the diameter of the second hole segment 1132 is smaller than the diameter of the first hole segment 1131, and the aforementioned first step surface 1133 can be formed between the first hole segment 1131 and the second hole segment 1132.

[0037] In one embodiment, the first hole segment 1131 and the second hole segment 1132 are both elliptical hole segments. The major axis and minor axis of the second hole segment 1132 are smaller than the major axis and minor axis of the first hole segment 1131, respectively. The aforementioned first step surface 1133 can also be formed between the first hole segment 1131 and the second hole segment 1132.

[0038] In one embodiment, both the first hole segment 1131 and the second hole segment 1132 are rectangular hole segments. The length and width of the second hole segment 1132 are smaller than the length and width of the first hole segment 1131. The aforementioned first step surface 1133 can also be formed between the first hole segment 1131 and the second hole segment 1132.

[0039] like Figure 4 As shown, the width of the first step surface 1133 is T1. It should be noted that the first step surface 1133 is typically a ring-shaped structure. Figure 4 In the middle, the width of the first step surface 1133 can be referenced to the width of the first step surface 1133 in the X-axis direction.

[0040] It should be noted that if the width T1 of the first step surface 1133 is too large, the opening size of the first hole section 1131 needs to be set larger to ensure exhaust efficiency, which may affect the structural strength of the cover plate 110. If the width of the first step surface 1133 is too small, it will not only affect the contact between the welding head and the explosion-proof valve 120, but also, after welding, the first step surface 1133 will not have enough area to form a weld mark, affecting the welding quality.

[0041] Therefore, in this embodiment of the application, the width T1 of the first step surface 1133 is limited to the following range: 0.5mm≤T1≤3mm. In this way, the problems caused by the aforementioned width T1 being too large or too small can be effectively improved.

[0042] In one embodiment, T1 can be selected as 0.5mm, 1.1mm, 3mm, etc.

[0043] like Figure 3 and Figure 4 As shown, the first side 111 includes a reference wall 1111 and a protruding wall 1112, the protruding wall 1112 being along a first direction (reference). Figure 3 and Figure 4 The Z-axis direction of the protrusion protrudes from the reference wall 1111, and the explosion-proof hole 113 penetrates the protruding wall 1112, that is, the position of the protruding wall 1112 corresponds to the position of the explosion-proof hole 113.

[0044] It should be noted that the protruding wall 1112 can enhance the overall rigidity and strength of the cover plate 110. During the welding process between the explosion-proof valve 120 and the cover plate 110, the protruding wall 1112 can resist welding stress, improving the problem of the cover plate 110 being prone to deformation and cracking during welding. In addition, the protruding wall 1112 can also prevent liquid foreign matter on the reference wall 1111 from flowing into the explosion-proof hole 113, preventing liquid foreign matter from damaging the explosion-proof valve 120.

[0045] In one embodiment, a protrusion can be formed into the aforementioned protruding wall 1112 by welding a protrusion onto the reference wall 1111.

[0046] In one embodiment, the protruding portion can be formed into the aforementioned protruding wall 1112 by stamping the reference wall 1111. During the stamping process, explosion-proof holes 113 can also be formed, effectively improving processing efficiency.

[0047] like Figure 4 As shown, the second hole section 1132 includes a first segment 11321, a second segment 11322 and a third segment 11323 connected sequentially along a first direction. The first segment 11321 is connected to the first hole section 1131. The end of the third segment 11323 away from the second segment 11322 passes through the protruding wall 1112 (that is, the third segment 11323 is located between the second segment 11322 and the protruding wall 1112). The explosion-proof valve 120 is disposed in the first segment 11321.

[0048] It should be understood that when the explosion-proof valve 120 is located within the first section 11321, a second section 11322 and a third section 11323 are reserved between the explosion-proof valve 120 and the protruding wall 1112. The second section 11322 and the third section 11323 can isolate the explosion-proof valve 120 from the external environment, prevent foreign objects from entering the explosion-proof valve 120, and ensure the explosion-proof performance of the explosion-proof valve 120.

[0049] like Figure 4 As shown, the projection of the inner wall of the second segment 11322 onto the reference plane (which can be understood as a plane parallel to the first side 111 and / or the second side 112) along the first direction is located inside the projection of the inner wall of the first segment 11321 onto the reference plane along the first direction, which allows a second stepped surface 11324 to be formed between the first segment 11321 and the second segment 11322. Thus, after the explosion-proof valve 120 is assembled into the first segment 11321, the explosion-proof valve 120 can abut against the second stepped surface 11324, and the second stepped surface 11324 can limit the movement of the explosion-proof valve 120, providing a stable state for the explosion-proof valve 120 during subsequent welding.

[0050] In one embodiment, the first segment 11321 and the second segment 11322 are both circular hole segments, the diameter of the second segment 11322 is smaller than the diameter of the first segment 11321, and the aforementioned second step surface 11324 can be formed between the first segment 11321 and the second segment 11322.

[0051] In one embodiment, both the first segment 11321 and the second segment 11322 are elliptical hole segments. The major axis and minor axis of the second segment 11322 are smaller than the major axis and minor axis of the first segment 11321, respectively. The aforementioned second step surface 11324 can also be formed between the first segment 11321 and the second segment 11322.

[0052] In one embodiment, the first segment 11321 and the second segment 11322 are both rectangular hole segments. The length and width of the second segment 11322 are both smaller than the length and width of the first segment 11321. The aforementioned second step surface 11324 can also be formed between the first segment 11321 and the second segment 11322.

[0053] like Figure 4 As shown, the width of the second step surface 11324 is T2. It should be noted that the second step surface 11324 is typically a ring-shaped structure. Figure 4 In the middle, the width of the second step surface 11324 can be referenced to the width of the second step surface 11324 in the X-axis direction.

[0054] It should be noted that if the width of the second step surface 11324 is too large, the opening size of the first segment 11321 needs to be set larger to ensure exhaust efficiency, which may easily affect the structural strength of the cover plate 110. If the width of the second step surface 11324 is too small, the contact area between the explosion-proof valve 120 and the second step surface 11324 will be small, affecting the abutment stability between the explosion-proof valve 120 and the second step surface 11324, causing the explosion-proof valve 120 to easily shake during welding, affecting the subsequent welding quality.

[0055] Therefore, in this embodiment of the application, the width T2 of the second step surface 11324 is limited to the following range: 0.3mm≤T2≤2.5mm. This can effectively improve the problems caused by the aforementioned width T2 being too large or too small.

[0056] In one embodiment, T2 can be selected as 0.3mm, 1.5mm, 2.5mm, etc.

[0057] like Figure 4As shown, the projection of the inner wall of the second segment 11322 onto the reference plane (which can be understood as a plane parallel to the first side 111 and / or the second side 112) along the first direction is located inside the projection of the inner wall of the third segment 11323 onto the reference plane along the first direction, so that a third step surface 11325 is formed between the second segment 11322 and the third segment 11323. Correspondingly, the cover plate assembly 100 may also include a protective film 130, which is disposed within the third segment 11323. The protective film 130 abuts against the third step surface 11325, and the third step surface 11325 can provide a bearing function for the protective film 130, facilitating the positioning and bonding of the protective film 130.

[0058] It should be noted that the protective film 130 is located in the third section 11323. The protective film 130 can cover the explosion-proof valve 120. The protective film 130 can prevent external foreign objects from entering the explosion-proof valve 120 and play a certain protective role for the explosion-proof valve 120.

[0059] In one embodiment, both the third segment 11323 and the second segment 11322 are circular hole segments, the diameter of the second segment 11322 is smaller than the diameter of the third segment 11323, and the aforementioned third step surface 11325 can be formed between the third segment 11323 and the second segment 11322.

[0060] In one embodiment, both the third segment 11323 and the second segment 11322 are elliptical hole segments. The major axis and minor axis of the second segment 11322 are smaller than the major axis and minor axis of the third segment 11323, respectively. The aforementioned third step surface 11325 can also be formed between the third segment 11323 and the second segment 11322.

[0061] In one embodiment, the third segment 11323 and the second segment 11322 are both rectangular hole segments. The length and width of the second segment 11322 are smaller than the length and width of the third segment 11323. The aforementioned third step surface 11325 can also be formed between the third segment 11323 and the second segment 11322.

[0062] like Figure 4 As shown, the width of the third step surface 11325 is T3. It should be noted that the third step surface 11325 is usually a ring-shaped structure. Figure 4 In the middle, the width of the third step surface 11325 can be referenced to the width of the third step surface 11325 in the X-axis direction.

[0063] It should be noted that if the width T3 of the third step surface 11325 is too large, the opening size of the third segment 11323 needs to be set larger to ensure exhaust efficiency, which may affect the structural strength of the cover plate 110. If the width T3 of the third step surface 11325 is too small, the contact area between the protective film 130 and the third step surface 11325 will be small, affecting the bonding stability between the protective film 130 and the third step surface 11325.

[0064] Therefore, in this embodiment of the application, the width T3 of the third step surface 11325 is limited to the following range: 0.3mm≤T3≤2.5mm. This can effectively improve the problems caused by the aforementioned width T3 being too large or too small.

[0065] In one embodiment, T3 can be selected from 0.3mm, 1.5mm, 2.5mm, etc.

[0066] In one embodiment, the width of the third step surface 11325 may be equal to or unequal to the width of the second step surface 11324.

[0067] like Figure 4 As shown, the explosion-proof valve 120 is also provided with a scoring groove 121. The thickness of the corresponding part of the scoring groove 121 is small. When the gas pressure inside the shell reaches the pressure threshold, the corresponding part of the scoring groove 121 will rupture first, and the gas will be released in time.

[0068] like Figure 4 As shown, the distance between the projection of the inner wall of the groove 121 along the first direction onto the reference plane (which can be understood as a plane parallel to the first side 111 and / or the second side 112) and the projection of the inner wall of the second segment 11322 along the first direction onto the reference plane is E. If the distance E is too large, the groove 121 may be too close to the middle of the explosion-proof valve 120, affecting the opening area of ​​the explosion-proof valve 120 and thus affecting the exhaust efficiency after the explosion-proof valve 120 is opened; if the distance E is too small, the groove 121 may be too close to the inner wall of the second segment 11322, and the second segment 11322 may hinder the explosion-proof valve 120 from opening in time. Even after the groove 121 is broken, the second segment 11322 may still block the gas from escaping, affecting the exhaust efficiency.

[0069] Therefore, in this embodiment of the application, the notched groove 121 is limited to the following range: 0.1mm≤E≤3mm. This can effectively improve the problems caused by the distance E being too large or too small.

[0070] In one embodiment, the distance E can be selected as 0.1mm, 2mm, 3mm, etc.

[0071] like Figure 4As shown, the first step surface 1133 and the reference wall 1111 are along the first direction (reference). Figure 4 The distance along the Z-axis is B. If the distance B is too small, the first step surface 1133 will be too close to the reference wall 1111, which will result in a smaller local thickness of the cover plate 110, affecting the overall structural strength of the cover plate 110. During the stamping process, the cover plate 110 is prone to cracks.

[0072] Therefore, in this embodiment of the application, the distance B is limited to the following range: B≥0.7mm. This can effectively improve the aforementioned problem caused by the distance B being too small.

[0073] In one embodiment, the distance B can be selected as 0.7mm, 1.2mm, etc.

[0074] like Figure 4 As shown, the distance between the first step surface 1133 and the second side 112 along the first direction is L. It should be noted that if the distance L is too small, considering the limitation of manufacturing precision, the cover plate 110 will not be easy to process and form, which will affect the production efficiency of the cover plate 110.

[0075] Therefore, in this embodiment of the application, the distance L is limited to the following range: L≥0.2mm.

[0076] It should be noted that, as Figure 4 In this context, C can be understood as the distance between the reference wall 1111 and the second side 112 along the first direction, where L = CB. By limiting the range of B as described above, the maximum value of L can be limited. This can effectively improve the problems caused by the excessive distance L (excessive distance L will cause the first step surface 1133 to be too close to the reference wall 1111, resulting in a smaller local thickness of the cover plate 110 and affecting the overall structural strength of the cover plate 110; or it may cause the distance between the reference wall 1111 and the second side 112 along the first direction to be too large, resulting in excessive material usage for the cover plate 110 and increased manufacturing costs).

[0077] In one embodiment, the distance L can be selected as 0.2mm, 2mm, etc.

[0078] like Figure 4 As shown, the projection of the edge of the protruding wall 1112 along the first direction onto the reference plane (which can be understood as a plane parallel to the first side 111 and / or the second side 112) is located inside the projection of the inner wall of the first hole segment 1131 along the first direction onto the reference plane; the distance between the projection of the edge of the protruding wall 1112 along the first direction onto the reference plane and the projection of the inner wall of the first hole segment 1131 along the first direction onto the reference plane is F.

[0079] It should be understood that if the distance F is too small, it will be difficult to form the protruding wall 1112 and the first hole segment 1131 using the stamping process, and cracks may easily appear in the cover plate 110 during the stamping process; if the distance F is too large, the opening size of the first hole segment 1131 needs to be set to be larger while ensuring the exhaust efficiency, which will affect the overall structural strength of the cover plate 110.

[0080] Therefore, in this embodiment of the application, the distance F is limited to the following range: 0.05mm≤F≤2mm. This can effectively improve the problems caused by the distance F being too large or too small.

[0081] In one embodiment, the distance F can be selected as 0.05mm, 0.12mm, 2mm, etc.

[0082] like Figure 2 and Figure 3 As shown, the cover plate assembly 100 may further include a terminal post assembly 140, which is disposed on the cover plate 110. In practical applications, the terminal post assembly 140 can be used to connect the tabs and the busbars on the electrode group, and to transmit current between the tabs and the busbars.

[0083] like Figure 3 As shown, the top end of the pole post assembly 140 protrudes relative to the reference wall 1111 along a first direction, and the distance between the top end of the pole post assembly 140 and the reference wall 1111 along the first direction is H. Figure 4 As shown, the distance between the protruding wall 1112 and the reference wall 1111 along the first direction is A.

[0084] It should be noted that if the distance A is too small, the protruding wall 1112 will have a poor blocking effect on external liquid foreign objects, which can easily enter the explosion-proof hole 113 and damage the protective film 130 and the explosion-proof valve 120. If the distance A exceeds H, the protruding wall 1112 will easily obstruct the welding operation between the terminal assembly 140 and the busbar, affecting the welding quality between the terminal assembly 140 and the busbar. Furthermore, if the protrusion height of the protruding wall 1112 is too high, it will occupy a large space in the first direction, reducing the volumetric energy density of the battery cell.

[0085] Therefore, in this embodiment of the application, the distance A is limited to the following range: 0.2mm≤A≤H. In this way, the problems caused by the distance A being too large or too small can be effectively improved.

[0086] In one embodiment, the distance A can be selected as 0.2mm, 0.5mm, etc.

[0087] The present application solution will be further described below with reference to specific embodiments.

[0088] Example 1 The battery cell includes a housing, electrode assembly, and cover plate assembly 100. The housing has an opening, and the electrode assembly is disposed within the housing. The cover plate assembly 100 includes a cover plate 110 and an explosion-proof valve 120. The cover plate 110 is disposed at one end of the electrode assembly and is connected to the housing to close the opening. The cover plate 110 includes a first side 111 and a second side 112 distributed along a first direction. The cover plate 110 has an explosion-proof hole 113 penetrating through the first side 111 and the second side 112. The explosion-proof hole 113 includes a first hole segment 1131 and a second hole segment 1132 distributed along the first direction. The end of the first hole segment 1131 away from the second hole segment 1132 penetrates through the second side 112, and the second hole segment 1132 communicates with the first hole segment 1131. The explosion-proof valve 120 is disposed within the second hole segment 1132.

[0089] The projection of the inner wall of the second hole segment 1132 onto the reference plane along the first direction is located inside the projection of the inner wall of the first hole segment 1131 onto the reference plane along the first direction, so that a first step surface 1133 is formed between the first hole segment 1131 and the second hole segment 1132, and the width of the first step surface 1133 is T1.

[0090] In this embodiment, T1 = 0.5 mm.

[0091] Example 2 This embodiment is basically the same as embodiment 1, except that: In this embodiment, T1 = 0.8 mm.

[0092] Example 3 This embodiment is basically the same as embodiment 1, except that: In this embodiment, T1 = 1.1 mm.

[0093] Example 4 This embodiment is basically the same as embodiment 1, except that: In this embodiment, T1 = 1.7 mm.

[0094] Example 5 This embodiment is basically the same as embodiment 1, except that: In this embodiment, T1 = 2.3 mm.

[0095] Example 6 This embodiment is basically the same as embodiment 1, except that: In this embodiment, T1 = 2.6 mm.

[0096] Example 7 This embodiment is basically the same as embodiment 1, except that: In this embodiment, T1 = 3 mm.

[0097] Comparative Example 1 This comparative example is basically the same as Example 1, except that: In this comparative example, T1 = 0.3 mm.

[0098] Comparative Example 2 This comparative example is basically the same as Example 1, except that: In this comparative example, T1 = 5 mm.

[0099] Test results The welded structure between the explosion-proof valve 120 and the cover plate 110 was inspected; the ability of the explosion-proof valve 120 to open normally was tested; and the structural strength of the stamped cover plate 110 was tested. The test results are shown in Table 1.

[0100] Table 1 Example 8 The battery cell includes a housing, electrode assembly, and cover plate assembly 100. The housing has an opening, and the electrode assembly is disposed inside the housing. The cover plate assembly 100 includes a cover plate 110, which is disposed at one end of the electrode assembly. The cover plate 110 is connected to the housing to close the opening. The cover plate 110 includes a first side 111 and a second side 112 distributed along a first direction. The cover plate 110 has an explosion-proof hole 113 penetrating through the first side 111 and the second side 112. The explosion-proof hole 113 includes a first hole segment 1131 and a second hole segment 1132 distributed along the first direction. The end of the first hole segment 1131 away from the second hole segment 1132 penetrates through the second side 112, and the second hole segment 1132 communicates with the first hole segment 1131.

[0101] The first side 111 includes a reference wall 1111 and a protruding wall 1112. The protruding wall 1112 protrudes relative to the reference wall 1111 along a first direction, and the explosion-proof hole 113 penetrates the protruding wall 1112. The second hole segment 1132 includes a first segment 11321, a second segment 11322, and a third segment 11323 that are connected along the first direction. The first segment 11321 is connected to the first hole segment 1131, and the end of the third segment 11323 away from the second segment 11322 penetrates the protruding wall 1112. The projection of the inner wall of the second segment 11322 onto the reference plane along the first direction is located inside the projection of the inner wall of the first segment 11321 onto the reference plane along the first direction, so that a second stepped surface 11324 is formed between the first segment 11321 and the second segment 11322.

[0102] The cover plate assembly 100 includes an explosion-proof valve 120, which is disposed within the first segment 11321 and abuts against the second step surface 11324. The width of the second step surface 11324 is T2.

[0103] In this embodiment, T2 = 0.3 mm.

[0104] Example 9 This embodiment is basically the same as embodiment 8, except that: In this embodiment, T2 = 0.8 mm.

[0105] Example 10 This embodiment is basically the same as embodiment 8, except that: In this embodiment, T2 = 1.1 mm.

[0106] Example 11 This embodiment is basically the same as embodiment 8, except that: In this embodiment, T2 = 1.4 mm.

[0107] Example 12 This embodiment is basically the same as embodiment 8, except that: In this embodiment, T2 = 1.7 mm.

[0108] Example 13 This embodiment is basically the same as embodiment 8, except that: In this embodiment, T2 = 2.5 mm.

[0109] Comparative Example 3 This comparative example is basically the same as Example 8, except that: In this comparative example, T2 = 0.05 mm.

[0110] Comparative Example 4 This comparative example is basically the same as Example 8, except that: In this comparative example, T2 = 4 mm.

[0111] Test results The welded structure between the explosion-proof valve 120 and the cover plate 110 was inspected; the ability of the explosion-proof valve 120 to open normally was tested; and the structural strength of the stamped cover plate 110 was tested. The test results are shown in Table 2.

[0112] Table 2 Example 14 The battery cell includes a housing, an electrode assembly, and a cover plate assembly 100. The housing has an opening, the electrode assembly is disposed inside the housing, and the cover plate assembly 100 includes a cover plate 110 disposed at one end of the electrode assembly. The cover plate 110 is connected to the housing to close the opening. The cover plate 110 includes a first side 111 and a second side 112 distributed along a first direction. The cover plate 110 has an explosion-proof hole 113 penetrating through the first side 111 and the second side 112. The explosion-proof hole 113 includes a first hole segment 1131 and a second hole segment 1132 distributed along the first direction. The end of the first hole segment 1131 away from the second hole segment 1132 penetrates through the second side 112, and the second hole segment 1132 communicates with the first hole segment 1131.

[0113] The first side 111 includes a reference wall 1111 and a protruding wall 1112. The protruding wall 1112 protrudes relative to the reference wall 1111 along a first direction, and the explosion-proof hole 113 penetrates the protruding wall 1112. The second hole segment 1132 includes a first segment 11321, a second segment 11322, and a third segment 11323 that are connected along the first direction. The first segment 11321 is connected to the first hole segment 1131, and the end of the third segment 11323 away from the second segment 11322 penetrates the protruding wall 1112. The projection of the inner wall of the second segment 11322 onto the reference plane along the first direction is located inside the projection of the inner wall of the first segment 11321 onto the reference plane along the first direction, so that a second stepped surface 11324 is formed between the first segment 11321 and the second segment 11322.

[0114] The cover assembly 100 includes an explosion-proof valve 120, which is disposed within the first segment 11321 and abuts against the second stepped surface 11324. The projection of the inner wall of the second segment 11322 onto the reference plane along the first direction is located inside the projection of the inner wall of the third segment 11323 onto the reference plane along the first direction, so that a third stepped surface 11325 is formed between the second segment 11322 and the third segment 11323.

[0115] The cover plate assembly 100 includes a protective film 130 disposed within the third segment 11323, and the protective film 130 abuts against the third step surface 11325. The width of the third step surface is T3.

[0116] In this embodiment, T3 = 0.3 mm.

[0117] Example 15 This embodiment is basically the same as embodiment 14, except that: In this embodiment, T3 = 0.9 mm.

[0118] Example 16 This embodiment is basically the same as embodiment 14, except that: In this embodiment, T3 = 1.4 mm.

[0119] Example 17 This embodiment is basically the same as embodiment 14, except that: In this embodiment, T3 = 1.7 mm.

[0120] Example 18 This embodiment is basically the same as embodiment 14, except that: In this embodiment, T3 = 2.1 mm.

[0121] Example 19 This embodiment is basically the same as embodiment 14, except that: In this embodiment, T3 = 2.5 mm.

[0122] Comparative Example 5 This comparative example is basically the same as Example 14, except that: In this comparative example, T3 = 0.1 mm.

[0123] Comparative Example 6 This comparative example is basically the same as Example 14, except that: In this comparative example, T3 = 3.2 mm.

[0124] Test results The structural strength of the stamped cover plate 110 was tested; the adhesion between the protective film 130 and the third step surface 11325 was tested. The test results are shown in Table 3.

[0125] Table 3 Example 20 The battery cell includes a housing, an electrode assembly, and a cover plate assembly 100. The housing has an opening, the electrode assembly is disposed inside the housing, and the cover plate assembly 100 includes a cover plate 110 disposed at one end of the electrode assembly. The cover plate 110 is connected to the housing to close the opening. The cover plate 110 includes a first side 111 and a second side 112 distributed along a first direction. The cover plate 110 has an explosion-proof hole 113 penetrating through the first side 111 and the second side 112. The explosion-proof hole 113 includes a first hole segment 1131 and a second hole segment 1132 distributed along the first direction. The end of the first hole segment 1131 away from the second hole segment 1132 penetrates through the second side 112, and the second hole segment 1132 communicates with the first hole segment 1131.

[0126] The first side 111 includes a reference wall 1111 and a protruding wall 1112. The protruding wall 1112 protrudes relative to the reference wall 1111 along a first direction, and the explosion-proof hole 113 penetrates the protruding wall 1112. The second hole segment 1132 includes a first segment 11321, a second segment 11322, and a third segment 11323 that are connected along the first direction. The first segment 11321 is connected to the first hole segment 1131, and the end of the third segment 11323 away from the second segment 11322 penetrates the protruding wall 1112. The projection of the inner wall of the second segment 11322 onto the reference plane along the first direction is located inside the projection of the inner wall of the first segment 11321 onto the reference plane along the first direction, so that a second stepped surface 11324 is formed between the first segment 11321 and the second segment 11322.

[0127] The cover plate assembly 100 includes an explosion-proof valve 120, which is disposed in the first segment 11321. The explosion-proof valve 120 abuts against the second step surface 11324. The explosion-proof valve 120 is provided with a scoring groove 121. The distance between the projection of the inner wall of the scoring groove 121 along the first direction onto the reference surface and the projection of the inner wall of the second segment 11322 along the first direction onto the reference surface is E.

[0128] In this embodiment, E = 0.1 mm.

[0129] Example 21 This embodiment is basically the same as embodiment 20, except that: In this embodiment, E = 0.8 mm.

[0130] Example 22 This embodiment is basically the same as embodiment 20, except that: In this embodiment, E = 1.1 mm.

[0131] Example 23 This embodiment is basically the same as embodiment 20, except that: In this embodiment, E = 1.4 mm.

[0132] Example 24 This embodiment is basically the same as embodiment 20, except that: In this embodiment, E = 1.7 mm.

[0133] Example 25 This embodiment is basically the same as embodiment 20, except that: In this embodiment, E = 2 mm.

[0134] Example 26 This embodiment is basically the same as embodiment 20, except that: In this embodiment, E = 2.3 mm.

[0135] Example 27 This embodiment is basically the same as embodiment 20, except that: In this embodiment, E = 2.6 mm.

[0136] Example 28 This embodiment is basically the same as embodiment 20, except that: In this embodiment, E = 3 mm.

[0137] Comparative Example 7 This comparative example is basically the same as Example 20, except that: In this comparative example, E = 0.3 mm.

[0138] Comparative Example 8 This comparative example is basically the same as Example 20, except that: In this comparative example, E = 5 mm.

[0139] Test results The ability of the explosion-proof valve 120 to open normally was tested; after the explosion-proof valve 120 was opened, the internal air pressure was tested. The test results are shown in Table 4.

[0140] Table 4 Example 29 The battery cell includes a housing, an electrode assembly, and a cover plate assembly 100. The housing has an opening, and the electrode assembly is disposed inside the housing. The cover plate assembly 100 includes a cover plate 110 and an explosion-proof valve 120. The cover plate 110 is disposed at one end of the electrode assembly and is connected to the housing to close the opening. The cover plate 110 includes a first side 111 and a second side 112 distributed along a first direction. The cover plate 110 has an explosion-proof hole 113 penetrating through the first side 111 and the second side 112. The explosion-proof hole 113 includes a first hole segment 1131 and a second hole segment 1132 distributed along the first direction. The end of the first hole segment 1131 away from the second hole segment 1132 penetrates through the second side 112, and the second hole segment 1132 communicates with the first hole segment 1131. The explosion-proof valve 120 is disposed inside the second hole segment 1132.

[0141] The first side 111 includes a reference wall 1111 and a protruding wall 1112. The protruding wall 1112 protrudes relative to the reference wall 1111 along a first direction, and the explosion-proof hole 113 penetrates the protruding wall 1112. The projection of the inner wall of the second hole segment 1132 along the first direction onto the reference plane is located inside the projection of the inner wall of the first hole segment 1131 along the first direction onto the reference plane, so that a first step surface 1133 is formed between the first hole segment 1131 and the second hole segment 1132. The distance between the first step surface 1133 and the reference wall 1111 along the first direction is B; the distance between the first step surface 1133 and the second side 112 along the first direction is L; and the distance between the reference wall 1111 and the second side 112 along the first direction is C.

[0142] In this embodiment, C=2mm; B=0.7mm; L=0.2mm.

[0143] Example 30 This embodiment is basically the same as embodiment 29, except that: In this embodiment, C=2mm; B=0.8mm; L=1.2mm.

[0144] Example 31 This embodiment is basically the same as embodiment 29, except that: In this embodiment, C=2mm; B=1mm; L=0.7mm.

[0145] Example 32 This embodiment is basically the same as embodiment 29, except that: In this embodiment, C=2mm; B=1.2mm; L=0.6mm.

[0146] Example 33 This embodiment is basically the same as embodiment 29, except that: In this embodiment, C=2mm; B=1.3mm; L=0.5mm.

[0147] Example 34 This embodiment is basically the same as embodiment 29, except that: In this embodiment, C=2mm; B=1.8mm; L=0.2mm.

[0148] Example 35 This embodiment is basically the same as embodiment 29, except that: In this embodiment, C=1.5mm; B=0.7mm; L=0.2mm.

[0149] Example 36 This embodiment is basically the same as embodiment 29, except that: In this embodiment, C=3mm; B=1mm; L=0.3mm.

[0150] Example 37 This embodiment is basically the same as embodiment 29, except that: In this embodiment, C=3mm; B=1.5mm; L=0.5mm.

[0151] Comparative Example 9 This comparative example is basically the same as Example 29, except that: In this comparative example, C=2mm; B=1mm; L=2mm.

[0152] Comparative Example 10 This comparative example is basically the same as Example 29, except that: In this comparative example, C = 2 mm; B = 0.3 mm; L = 1 mm.

[0153] Comparative Example 11 This comparative example is basically the same as Example 29, except that: In this comparative example, C=2mm; B=1mm; L=0.1mm.

[0154] Test results The defect rate of the cover plate 110 was tested, and whether the explosion-proof valve 120 was scratched by the lower plastic 150 was tested. The test results are shown in Table 5.

[0155] Table 5 Example 38 The battery cell includes a housing, an electrode assembly, and a cover plate assembly 100. The housing has an opening, and the electrode assembly is disposed inside the housing. The cover plate assembly 100 includes a cover plate 110 and an explosion-proof valve 120. The cover plate 110 is disposed at one end of the electrode assembly and is connected to the housing to close the opening. The cover plate 110 includes a first side 111 and a second side 112 distributed along a first direction. The cover plate 110 has an explosion-proof hole 113 penetrating through the first side 111 and the second side 112. The explosion-proof hole 113 includes a first hole segment 1131 and a second hole segment 1132 distributed along the first direction. The end of the first hole segment 1131 away from the second hole segment 1132 penetrates through the second side 112, and the second hole segment 1132 communicates with the first hole segment 1131. The explosion-proof valve 120 is disposed inside the second hole segment 1132. The first side 111 includes a reference wall 1111 and a protruding wall 1112. The protruding wall 1112 protrudes relative to the reference wall 1111 along a first direction, and the explosion-proof hole 113 penetrates the protruding wall 1112.

[0156] The projection of the edge of the protruding wall 1112 along the first direction onto the reference plane is located inside the projection of the inner wall of the first hole segment 1131 along the first direction onto the reference plane; the distance between the projection of the edge of the protruding wall 1112 along the first direction onto the reference plane and the projection of the inner wall of the first hole segment 1131 along the first direction onto the reference plane is F.

[0157] In this embodiment, F = 0.05 mm.

[0158] Example 39 This embodiment is basically the same as embodiment 29, except that: In this embodiment, F = 0.2 mm.

[0159] Example 40 This embodiment is basically the same as embodiment 29, except that: In this embodiment, F = 0.5 mm.

[0160] Example 41 This embodiment is basically the same as embodiment 29, except that: In this embodiment, F = 1 mm.

[0161] Example 42 This embodiment is basically the same as embodiment 29, except that: In this embodiment, F = 1.4 mm.

[0162] Example 43 This embodiment is basically the same as embodiment 29, except that: In this embodiment, F = 2 mm.

[0163] Comparative Example 12 This comparative example is basically the same as Example 29, except that: In this comparative example, F=0.

[0164] Comparative Example 13 This comparative example is basically the same as Example 29, except that: In this comparative example, F = 4 mm.

[0165] Test results The defect rate of the cover plate 110 was tested. The test results are shown in Table 6.

[0166] Table 6 Example 44 The battery cell includes a housing, an electrode assembly, and a cover plate assembly 100. The housing has an opening, and the electrode assembly is disposed inside the housing. The cover plate assembly 100 includes a cover plate 110 and an explosion-proof valve 120. The cover plate 110 is disposed at one end of the electrode assembly and is connected to the housing to close the opening. The cover plate 110 includes a first side 111 and a second side 112 distributed along a first direction. The cover plate 110 has an explosion-proof hole 113 penetrating through the first side 111 and the second side 112. The explosion-proof hole 113 includes a first hole segment 1131 and a second hole segment 1132 distributed along the first direction. The end of the first hole segment 1131 away from the second hole segment 1132 penetrates through the second side 112, and the second hole segment 1132 communicates with the first hole segment 1131. The explosion-proof valve 120 is disposed inside the second hole segment 1132. The first side 111 includes a reference wall 1111 and a protruding wall 1112. The protruding wall 1112 protrudes relative to the reference wall 1111 along a first direction, and the explosion-proof hole 113 penetrates the protruding wall 1112.

[0167] The cover plate assembly 100 also includes a pole post assembly 140, which is disposed on the cover plate 110. The top end of the pole post assembly 140 protrudes relative to the reference wall 1111 along a first direction. The distance between the top end of the pole post assembly 140 and the reference wall 1111 along the first direction is H, and the distance between the protruding wall 1112 and the reference wall 1111 along the first direction is A.

[0168] In this embodiment, A = 0.2 mm; H = 3.2 mm.

[0169] Example 45 This embodiment is basically the same as embodiment 44, except that: In this embodiment, A = 0.8 mm; H = 3.2 mm.

[0170] Example 46 This embodiment is basically the same as embodiment 44, except that: In this embodiment, A = 1.4 mm; H = 3.2 mm.

[0171] Example 47 This embodiment is basically the same as embodiment 44, except that: In this embodiment, A = 1.7 mm; H = 3.2 mm.

[0172] Example 48 This embodiment is basically the same as embodiment 44, except that: In this embodiment, A = 2 mm; H = 3.2 mm.

[0173] Example 49 This embodiment is basically the same as embodiment 44, except that: In this embodiment, A = 2.6 mm; H = 3.2 mm.

[0174] Example 50 This embodiment is basically the same as embodiment 44, except that: In this embodiment, A = 3.2 mm; H = 3.2 mm.

[0175] Comparative Example 14 This comparative example is basically the same as Example 44, except that: In this comparative example, A = 0.1 mm; H = 3.2 mm.

[0176] Comparative Example 15 This comparative example is basically the same as Example 44, except that: In this comparative example, A = 5 mm; H = 3.2 mm.

[0177] Test results The protective film 130 and the explosion-proof valve 120 were tested for contamination by electrolyte or other liquids, and the volumetric energy density of the battery cell was measured. The test results are shown in Table 7.

[0178] Table 7 The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0179] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0180] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.

[0181] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0182] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A cover assembly, characterized by The cover plate comprises a first side and a second side distributed along a first direction; the cover plate is provided with an explosion-proof hole penetrating through the first side and the second side; the explosion-proof hole comprises a first hole section and a second hole section distributed along the first direction, the second hole section is in communication with the first hole section, and an end of the first hole section away from the second hole section penetrates through the second side; wherein the first direction represents the thickness direction of the cover plate; The explosion-proof valve is arranged in the second hole section. The projection of the inner wall of the second hole section on a reference surface along the first direction is located inside the projection of the inner wall of the first hole section on the reference surface along the first direction, so as to form a first step surface between the first hole section and the second hole section; wherein the reference surface represents a plane parallel to the first side and / or the second side.

2. The cover plate assembly of claim 1, wherein, The width of the first step surface is T1, and the T1 satisfies: 0.5mm≤T1≤3mm; and / or, 3. The cover plate assembly of claim 2, wherein, The distance between the first step surface and the second side along the first direction is L, and the L satisfies: L≥0.2mm. The first side comprises a reference wall and a convex wall, the convex wall is convex relative to the reference wall along the first direction, and the explosion-proof hole penetrates through the convex wall.

4. The cover plate assembly of any one of claims 1 to 3, wherein, The second hole section comprises a first sub-section, a second sub-section and a third sub-section in communication along the first direction, the first sub-section is in communication with the first hole section, and an end of the third sub-section away from the second sub-section penetrates through the convex wall; 5. The cover plate assembly of claim 4, wherein, wherein the projection of the inner wall of the second sub-section on a reference surface along the first direction is located inside the projection of the inner wall of the first sub-section on the reference surface along the first direction, so as to form a second step surface between the first sub-section and the second sub-section, the explosion-proof valve is arranged in the first sub-section, and the explosion-proof valve abuts against the second step surface; wherein the reference surface represents a plane parallel to the first side and / or the second side. The width of the second step surface is T2, and the T2 satisfies: 0.3mm≤T2≤2.5mm.

6. The cover plate assembly of claim 5, wherein, The projection of the inner wall of the second sub-section on the reference surface along the first direction is located inside the projection of the inner wall of the third sub-section on the reference surface along the first direction, so as to form a third step surface between the second sub-section and the third sub-section; wherein the width of the third step surface is T3, and the T3 satisfies: 0.3mm≤T3≤2.5mm; 7. The cover plate assembly of claim 5, wherein, The cover plate assembly further comprises: A protective film arranged in the third sub-section, and the protective film abuts against the third step surface. The explosion-proof valve is provided with a notch groove, the distance between the projection of the inner wall of the notch groove on the reference surface along the first direction and the projection of the inner wall of the second sub-section on the reference surface along the first direction is E, and the E satisfies: 0.1mm≤E≤3mm.

8. The cover plate assembly of claim 5, wherein, ​ 9. The cover plate assembly of claim 4, wherein, a projection of an inner wall of the second hole section on a reference plane in the first direction is located inside a projection of an inner wall of the first hole section on the reference plane in the first direction, so as to form a first stepped surface between the first hole section and the second hole section; wherein the reference plane represents a plane parallel to the first side and / or the second side; a distance between the first stepped surface and the reference wall in the first direction is B, and the B satisfies: B≥0.7mm; and / or, a projection of an edge of the convex wall on a reference plane in the first direction is located inside a projection of an inner wall of the first hole section on the reference plane in the first direction; wherein the reference plane represents a plane parallel to the first side and / or the second side; a distance between the projection of the edge of the convex wall on the reference plane in the first direction and the projection of the inner wall of the first hole section on the reference plane in the first direction is F, and the F satisfies: 0.05mm≤F≤2mm; and / or, the cover plate assembly further comprises: a pole assembly arranged on the cover plate, a top end of the pole assembly protrudes from the reference wall in the first direction; wherein a distance between the top end of the pole assembly and the reference wall in the first direction is H, a distance between the convex wall and the reference wall in the first direction is A, and the A and the H satisfy: 0.2mm≤A≤H.

10. An electric cell characterized by comprises: a shell provided with an opening; a pole group arranged in the shell; the cover plate assembly according to any one of claims 1 to 9, the cover plate is arranged at one end of the pole group, and the cover plate is connected with the shell to close the opening.

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