Cover plate structure and battery cell

Abstract

The utility model relates to energy storage equipment technical field especially relates to a cover plate structure and electric core, cover plate structure includes top cap, compound pole and welding plate. Top cap is set with N first through -hole, N is positive integer. Compound pole includes bottom plate and N cylinder, N cylinder is connected in bottom plate, N cylinder is respectively worn in N first through -hole, bottom plate sets up in the side of top cap towards electric core inside. Welding plate sets up in the side of top cap towards electric core inside, bottom plate and welding plate weld, and welding plate is used for with the tab or connecting piece welding of pole group. Electric core includes casing and above -mentioned cover plate structure, and cover plate structure cover sets up at the opening place of casing. The cover plate structure and electric core can improve the welding area of output assembly and the tab or connecting piece of pole group, guarantee the displacement of lower plastic at the same time, reduce the processing cost of compound pole.

Description

Technical Field

[0001] This utility model relates to the field of energy storage equipment technology, and in particular to a cover plate structure and a battery cell. Background Technology

[0002] The cover structure of a battery cell includes a terminal post. One end of the terminal post, located inside the cell, has a base plate. This base plate is used for welding to the electrode tabs or connectors of the electrode assembly, and it also supports and secures the lower plastic component, preventing displacement. The terminal post in the cover structure located at the negative electrode is typically made of a copper-aluminum composite material. If the base plate of the terminal post is very large, it cannot be processed using low-cost methods such as pressing; instead, it requires more expensive machining processes, undoubtedly increasing the cost of the cover structure. Utility Model Content

[0003] One objective of this invention is to provide a cover plate structure that can increase the welding area of ​​the output component and the electrode lugs or connectors, ensure that the lower plastic does not shift, and reduce the processing cost of the composite electrode post.

[0004] To achieve this objective, the present invention adopts the following technical solution:

[0005] A cover plate structure is provided, comprising:

[0006] The top cover has N first through holes, where N is a positive integer;

[0007] A composite electrode post includes a base plate and N pillars, the N pillars being connected to the base plate and the N pillars being respectively inserted through N first through holes, the base plate being disposed on the side of the top cover facing the inside of the battery cell;

[0008] A welding plate is disposed on the side of the top cover facing the inside of the cell, and the bottom plate is welded to the welding plate. The welding plate is used for welding to the tabs or connectors of the electrode assembly.

[0009] Optionally, along the length of the base plate, the minimum distance d between the outer wall of the column and the side wall of the base plate satisfies: 0.5mm≤d≤3mm;

[0010] And / or, along the direction perpendicular to the surface of the base plate, the thickness e of the base plate satisfies: 0.5mm≤e≤1mm;

[0011] And / or, along the direction perpendicular to the surface of the base plate, the weld penetration h of the base plate and the welding plate and the thickness e of the base plate satisfy: 0.3mm≤h≤e.

[0012] Optionally, the welding plate is sandwiched between the base plate and the top cover, the welding plate has a receiving groove, the bottom of the receiving groove has N second through holes, the N columns are respectively inserted through the N second through holes, and the base plate is located in the receiving groove.

[0013] Optionally, the welding plate has a receiving groove, and the receiving groove is formed at the bottom of the receiving groove. The thickness of the bottom plate is consistent with the depth of the receiving groove along the direction perpendicular to the surface of the bottom plate.

[0014] Optionally, the bottom of the receiving groove is a first annular structure, and the width f of the first annular structure satisfies: 0.5mm≤f≤1mm;

[0015] And / or, along the direction perpendicular to the surface of the base plate, the groove depth g of the receiving groove satisfies: 0.2mm≤g≤0.5mm.

[0016] Optionally, it also includes a conductive block disposed on the side of the top cover facing the outside of the battery cell, and all N pillars are welded to the conductive block.

[0017] Optionally, the conductive block is provided with a clearance groove, and the bottom of the clearance groove is provided with N third through holes. The N pillars are respectively inserted through the N third through holes, and the N pillars are all welded to the bottom of the clearance groove.

[0018] Optionally, the bottom of the clearance groove is a second annular structure, and the width a of the second annular structure along the radial direction of the second annular structure satisfies: 0.5mm≤a≤1mm;

[0019] And / or, along the axial direction of the column, the groove depth b of the clearance groove satisfies: 0.2mm≤b≤0.5mm;

[0020] And / or, along the axial direction of the column, the weld penetration depth c between the column and the bottom of the clearance groove satisfies: 0.3mm≤c≤1mm.

[0021] Optionally, both the welding plate and the base plate are made of a first material, the end of the column away from the base plate is made of a second material, and the conductive block is made of the second material;

[0022] And / or, the composite pole is a pole formed by pressing.

[0023] Another objective of this invention is to provide a battery cell that can reduce the processing cost of composite poles while increasing the welding area of ​​the output components and electrode group tabs or connectors and ensuring that the lower plastic does not shift.

[0024] To achieve this objective, the present invention adopts the following technical solution:

[0025] A battery cell is provided, including a housing and the aforementioned cover structure, the cover structure covering an opening in the housing.

[0026] The beneficial effects of this utility model are:

[0027] This utility model provides a cover plate structure, including a top cover, a composite electrode post, and a welding plate. The top cover has N first through holes, where N is a positive integer. The composite electrode post includes a base plate and N pillars, with the N pillars connected to the base plate and passing through the N first through holes. The base plate is located on the side of the top cover facing the inside of the battery cell. The welding plate is located on the side of the top cover facing the inside of the battery cell, and the base plate is welded to the welding plate. The welding plate is used for welding to the tabs or connectors of the electrode assembly. Increasing the size of the welding plate provides sufficient space to increase the welding area with the tabs or connectors of the electrode assembly, and helps prevent the lower plastic from shifting. Furthermore, the composite electrode post does not require an excessively large base plate, reducing the processing difficulty and allowing for low-cost processing techniques such as pressing. Therefore, this cover plate structure can increase the welding area between the output component and the tabs or connectors of the electrode assembly, ensure the lower plastic does not shift, and reduce the processing cost of the composite electrode post. The output component includes the composite electrode post and the welding plate.

[0028] This utility model also provides a battery cell, including a housing and the aforementioned cover plate structure. The cover plate structure is disposed at the opening of the housing. This battery cell can increase the welding area of ​​the output component and the electrode group's tabs or connectors, ensure that the lower plastic does not shift, and reduce the processing cost of the composite electrode post. Attached Figure Description

[0029] Figure 1 This is a first-view structural schematic diagram of the cover plate structure provided in this embodiment of the utility model;

[0030] Figure 2 This is a second-view structural schematic diagram of the cover plate structure provided in this embodiment of the utility model;

[0031] Figure 3 This is an exploded view of the cover plate structure provided in this embodiment of the utility model;

[0032] Figure 4 This is a cross-sectional view of the cover plate structure provided in this embodiment of the utility model;

[0033] Figure 5 This is a partially enlarged cross-sectional view of the cover plate structure provided in this embodiment of the utility model.

[0034] In the picture:

[0035] 1. Top cover; 11. First through hole;

[0036] 2. Composite pole; 21. Base plate; 22. Column; 221. First part; 222. Second part;

[0037] 3. Welding plate; 31. Receiving groove;

[0038] 4. Conductive block; 41. Clearance groove; 42. Third through hole;

[0039] 5. Bottom plastic; 6. Top plastic; 7. Sealing ring. Detailed Implementation

[0040] The technical solution of this utility model will be further described below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for explaining this utility model and not for limiting it. Furthermore, it should be noted that, for ease of description, only the parts related to this utility model are shown in the drawings, not all of them.

[0041] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections or detachable connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0042] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0043] The cover structure of a battery cell includes a terminal post. One end of the terminal post, located inside the cell, has a base plate. This base plate is used for welding to the electrode tabs or connectors of the electrode assembly, and it also supports and secures the lower plastic component, preventing displacement. The terminal post in the cover structure located at the negative electrode is typically made of a copper-aluminum composite material. If the base plate of the terminal post is very large, it cannot be processed using low-cost methods such as pressing; instead, it requires more expensive machining processes, undoubtedly increasing the cost of the cover structure.

[0044] To address the aforementioned issues, this embodiment provides a cover plate structure that can increase the welding area between the output component and the electrode group's tabs or connectors, ensure that the lower plastic 5 does not shift, and reduce the processing cost of the composite electrode post.

[0045] like Figures 1-5 As shown, the cover plate structure of this embodiment includes a top cover 1, a composite electrode post 2, and a welding plate 3. The top cover 1 has N first through holes 11, where N is a positive integer. The composite electrode post 2 includes a base plate 21 and N pillars 22. The N pillars 22 are connected to the base plate 21 and pass through the N first through holes 11. The base plate 21 is located on the side of the top cover 1 facing the inside of the battery cell. The welding plate 3 is located on the side of the top cover 1 facing the inside of the battery cell. The base plate 21 is welded to the welding plate 3, which is used for welding to the electrode tabs or connectors of the electrode assembly.

[0046] Increasing the size of the welding plate 3 provides sufficient space for increasing the welding area with the electrode lugs or connectors of the electrode assembly, and helps prevent the lower plastic 5 from shifting. Simultaneously, the composite electrode post 2 does not require an excessively large base plate 21, reducing the processing difficulty of the composite electrode post 2, allowing for the use of low-cost processing techniques such as pressing. Therefore, this cover plate structure can increase the welding area between the output component and the electrode lugs or connectors of the electrode assembly, ensure the lower plastic 5 does not shift, and reduce the processing cost of the composite electrode post. The output component includes the composite electrode post 2 and the welding plate 3.

[0047] Optionally, in this embodiment, N is set to 2. By setting two pillars 22, the current carrying capacity of the cover plate structure can be increased. Optionally, in order to accommodate the narrow top cover 1 of the blade cell, the two pillars 22 are arranged alternately along the length direction of the top cover 1.

[0048] Of course, in other embodiments, N can also be a positive integer of 3, 4, 5 or larger.

[0049] Optionally, the welding plate 3 is sandwiched between the bottom plate 21 and the top cover 1. The end face of the welding plate 3 facing the inside of the cell has a receiving groove. The bottom of the receiving groove has N second through holes. N pillars 22 are respectively inserted through the N second through holes. The bottom plate 21 is located in the receiving groove, and the receiving groove can limit the bottom plate 21.

[0050] To prevent the weld marks on the base plate 21 and the welding plate 3 from protruding from the end face of the welding plate 3 facing the inside of the battery cell, the welding plate 3 may optionally have a receiving groove 31. The bottom of the receiving groove 31 has a receiving groove, allowing the weld marks to be located within the receiving groove 31. Along the direction perpendicular to the surface of the base plate 21, the thickness of the base plate 21 is consistent with the depth of the receiving groove, meaning that the end face of the base plate 21 facing the inside of the battery cell is flush with the bottom of the receiving groove 31. The receiving groove is compatible with the base plate 21, facilitating welding between the base plate 21 and the bottom of the receiving groove 31 and ensuring welding quality.

[0051] Optionally, in this embodiment, the cross-section of the column 22 is circular and the base plate 21 is rectangular. Of course, in other embodiments, the cross-section of the column 22 may also be elliptical, polygonal or irregular, and the base plate 21 may also be circular, elliptical, other polygonal or irregular.

[0052] Optionally, along the length of the base plate 21, the minimum distance d between the outer wall of the column 22 and the side wall of the base plate 21 satisfies: 0.5mm ≤ d ≤ 3mm. If the value of d is less than 0.5mm, the base plate 21 cannot securely hold the welding plate 3, preventing the welding plate 3 from adhering tightly to the side of the top cover 1 facing the inside of the battery cell. Furthermore, if the value of d is too small, machining errors can easily affect the integrity of the column 22, impacting electrical conductivity. If the value of d is greater than 3mm, to ensure the machining quality of the composite electrode 2, it is best to use more complex processes such as turning to machine the composite electrode 2, increasing machining costs.

[0053] Optionally, the value of d can be 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, or 3mm.

[0054] Optionally, along the direction perpendicular to the surface of the base plate 21, the thickness e of the base plate 21 satisfies: 0.5mm ≤ e ≤ 1mm. If the value of e is less than 0.5mm, the structural strength of the base plate 21 is insufficient, and the base plate 21 is prone to deformation during the pressing and forming process of the composite pole 2, causing assembly problems and affecting the quality of the cover plate structure. If the value of e is greater than 3mm, the base plate 21 is too thick, resulting in a large amount of material consumption and high cost. Furthermore, when the thickness of the welding plate 3 remains unchanged, the thickness of the bottom of the receiving groove will be too small, affecting the structural strength of the bottom of the receiving groove, which will affect the support force on the sealing ring 7 and lead to sealing failure and other problems.

[0055] Optionally, the value of e can be 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm or 1mm.

[0056] Optionally, along the direction perpendicular to the surface of the base plate 21, the weld penetration depth h between the base plate 21 and the welding plate 3 and the thickness e of the base plate 21 satisfy: 0.3mm ≤ h ≤ e. If the value of h is less than 0.3mm, the weld strength is insufficient, and the internal resistance between the base plate 21 and the welding plate 3 of the pole post will be too large. If the value of h is greater than the thickness e of the base plate 21, weld explosions are likely to occur, causing safety accidents and reducing product yield.

[0057] Optionally, when the thickness e of the base plate 21 is 1 mm, the value of h is 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm or 1 mm.

[0058] Optionally, the bottom of the receiving groove 31 is a first annular structure. In this embodiment, the bottom plate 21 is rectangular, and the sidewalls of the receiving groove 31 are also rectangular. The width of the first annular structure is consistent throughout the circumference to ensure that the receiving groove 31 can accommodate solder marks in a consistent circumferential direction. Therefore, the first annular structure is a rectangular ring.

[0059] Optionally, the width f of the first annular structure satisfies: 0.5mm ≤ f ≤ 1mm. If the value of f is less than 0.5mm, the receiving groove 31 is insufficient to accommodate the weld marks between the base plate 21 and the bottom of the receiving groove 31, and the sidewall of the receiving groove 31 will interfere with the welding operation, resulting in insufficient welding strength and weld marks on the end face of the welding plate 3 closest to the electrode group. If the value of f is greater than 1mm, the opening of the receiving groove 31 is too large. If the width of the welding plate 3 remains unchanged, the structural strength at both ends of the welding plate 3 will decrease along the width direction. If the width of the welding plate 3 is increased, it cannot be used for narrow blade cells.

[0060] Optionally, f can be 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm or 1mm.

[0061] Optionally, along the direction perpendicular to the surface of the base plate 21, the groove depth g of the receiving groove 31 satisfies: 0.2mm ≤ g ≤ 0.5mm. When the value of g is less than 0.2mm, the receiving groove 31 is too shallow and insufficient to accommodate the weld marks between the base plate 21 and the bottom of the receiving groove 31. The weld marks are likely to protrude from the end face of the welding plate 3 closest to the electrode assembly, and the protruding part of the weld marks may scratch the electrode tabs and other components. When the value of g is greater than 0.5mm, the receiving groove 31 is too deep. When the overall thickness of the welding plate 3 remains unchanged, the excessive depth of the receiving groove 31 will affect the groove depth and the thickness of the bottom of the receiving groove. If the receiving groove is too shallow, it will not be able to accommodate the base plate 21, resulting in the base plate 21 and the bottom of the receiving groove 31 not being flush, affecting the welding quality. If the thickness of the bottom of the receiving groove is too small, the local structural strength will be insufficient, making it easy to deform under stress, causing problems such as insufficient compression of the sealing ring 7 and sealing failure.

[0062] Optionally, the value of g can be 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm or 0.5mm.

[0063] Optionally, the cover structure also includes a conductive block 4, which is disposed on the side of the top cover 1 facing the outside of the battery cell. All N pillars 22 are welded to the conductive block 4, and the conductive block 4 is used to conduct electricity to the outside.

[0064] Optionally, a clearance groove 41 is formed on the end face of the conductive block 4 facing the outer side of the battery cell. N third through holes 42 are formed at the bottom of the clearance groove 41, and N pillars 22 are respectively inserted through the N third through holes 42. All N pillars 22 are welded to the bottom of the clearance groove 41. The clearance groove 41 can accommodate the weld marks between the pillars 22 and the clearance groove 41.

[0065] Optionally, in this embodiment, the cross-section of the column 22 is circular, the clearance groove 41 is also a cylindrical groove, and the clearance groove 41 is coaxially arranged with the corresponding column 22.

[0066] Optionally, the bottom of the clearance groove 41 is a second annular structure, and the width of the second annular structure is consistent throughout the circumference. Optionally, the width 'a' of the second annular structure along the radial direction satisfies: 0.5mm ≤ a ≤ 1mm. That is, the width 'a' of the second annular structure at all points along the circumference conforms to the above-mentioned value range. If the value of 'a' is less than 0.5mm, the clearance groove 41 is insufficient to accommodate the weld marks between the column 22 and the bottom of the clearance groove 41, and the sidewall of the clearance groove 41 will interfere with the welding operation, resulting in insufficient welding strength and weld marks on the end face of the conductive block 4 furthest from the electrode group. If the value of 'a' is greater than 1mm, the opening of the clearance groove 41 is too large. If the width of the conductive block 4 remains unchanged, the structural strength on both sides of the conductive block 4 will decrease along the width direction. If the width of the conductive block 4 is increased, it is not suitable for narrow blade cells.

[0067] Optionally, the value of 'a' can be 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, or 1mm.

[0068] Optionally, along the axial direction of the column 22, the groove depth b of the clearance groove 41 satisfies: 0.2mm ≤ b ≤ 0.5mm. When the value of b is less than 0.2mm, the clearance groove 41 is too shallow and insufficient to accommodate the weld marks between the column 22 and the bottom of the clearance groove 41. The weld marks are likely to protrude from the end face of the conductive block 4 furthest from the electrode group, scratching other components outside the battery cell and affecting the contact and conduction between the end face of the conductive block 4 furthest from the electrode group and the outside. When the value of b is greater than 0.5mm, the clearance groove 41 is too deep. When the overall thickness of the conductive block 4 remains unchanged, the excessive depth of the clearance groove 41 will affect the structural strength of the conductive block 4.

[0069] Optionally, the value of b can be 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm or 0.5mm.

[0070] Optionally, along the axial direction of the column 22, the weld penetration depth c between the column 22 and the bottom of the relief groove 41 satisfies: 0.3mm ≤ c ≤ 1mm. If the value of c is less than 0.3mm, the weld strength is insufficient, and the internal resistance between the column 22 of the pole and the conductive block 4 will be too large. If the value of c is greater than 1mm, weld explosions are likely to occur, causing safety accidents and reducing product yield.

[0071] Optionally, the value of c can be 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm or 1mm.

[0072] Optionally, the welding plate 3 and the base plate 21 are both made of a first material, the end of the column 22 away from the base plate 21 is made of a second material, and the conductive block 4 is made of a second material. Optionally, the first material is copper, and the second material is aluminum. Optionally, the composite pole 2 includes a first part 221 and a second part 222 arranged sequentially along the axial direction. The first part 221 is located near the outside of the cell, and the material of the first part 221 is aluminum. The material of the second part 222 is copper, and the second part 222 includes the base plate 21 and part of the column 22.

[0073] Optionally, the composite pole 2 is a pole formed by pressing. Since the size of the base plate 21 does not need to be too large, the pressing process can meet the size requirements of the composite pole 2 and significantly reduce the processing cost.

[0074] Optionally, the cover structure also includes a lower plastic 5, which is attached to the side of the top cover 1 facing the inside of the battery cell, and the lower plastic 5 is partially sandwiched between the bottom plate 21 and the top cover 1 to ensure insulation between the two.

[0075] Optionally, the cover structure also includes an upper plastic 6, which is partially sandwiched between the conductive block 4 and the top cover 1. The upper plastic 6 has a side to wrap the side wall of the conductive block 4, and the upper plastic 6 also has a protruding ring protruding towards the inside of the battery cell. The protruding ring is inserted into the first through hole 11 to be sandwiched between the inner wall of the first through hole 11 and the column 22, so as to ensure insulation between the composite pole 2 and the top cover 1.

[0076] Optionally, the cover plate structure also includes a sealing ring 7, which is sleeved on the column 22 and located in the fourth through hole of the lower plastic 5. The protruding ring of the upper plastic 6 abuts against the end face of the sealing ring 7 facing the outside of the battery cell, and the end face of the sealing ring 7 facing the outside of the battery cell seals the gap between the protruding ring and the inner wall of the first through hole 11 to improve the sealing performance of the cover plate structure. The end face of the sealing ring 7 facing the inside of the battery cell abuts against the welding plate 3.

[0077] This embodiment also provides a battery cell, including a housing and the aforementioned cover structure, the cover structure being disposed at the opening of the housing. Optionally, in this embodiment, the cover structure is disposed at the negative electrode of the battery cell. Of course, in other embodiments, the cover structure can also be disposed at the positive electrode. The composite electrode post 2 of the cover structure at the positive electrode can be replaced with an electrode post made of a single material, which is not limited here.

[0078] This battery cell can reduce the processing cost of composite poles while increasing the welding area of ​​the output components and electrode group tabs or connectors and ensuring that the lower plastic 5 does not shift.

[0079] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A cover plate structure, characterized in that, include: The top cover (1) has N first through holes (11), where N is a positive integer; The composite pole (2) includes a base plate (21) and N poles (22), the N poles (22) are connected to the base plate (21), the N poles (22) are respectively inserted through the N first through holes (11), and the base plate (21) is located on the side of the top cover (1) facing the inside of the cell; Welding plate (3), the welding plate (3) is disposed on the side of the top cover (1) facing the inside of the cell, the bottom plate (21) is welded to the welding plate (3), the welding plate (3) is used to weld to the electrode tabs or connectors of the electrode assembly.

2. The cover plate structure according to claim 1, characterized in that, Along the length of the base plate (21), the minimum distance d between the outer wall of the column (22) and the side wall of the base plate (21) satisfies: 0.5mm≤d≤3mm; And / or, along the direction perpendicular to the surface of the base plate (21), the thickness e of the base plate (21) satisfies: 0.5mm≤e≤1mm; And / or, along the direction perpendicular to the surface of the base plate (21), the welding penetration h of the base plate (21) and the welding plate (3) and the thickness e of the base plate (21) satisfy: 0.3mm≤h≤e.

3. The cover plate structure according to claim 1, characterized in that, The welding plate (3) is partially sandwiched between the bottom plate (21) and the top cover (1). The welding plate (3) has a receiving groove. The bottom of the receiving groove has N second through holes. The N columns (22) are respectively inserted through the N second through holes. The bottom plate (21) is located in the receiving groove.

4. The cover plate structure according to claim 3, characterized in that, The welding plate (3) has a receiving groove (31), and the receiving groove is provided at the bottom of the receiving groove (31). The thickness of the bottom plate (21) is consistent with the depth of the receiving groove along the direction perpendicular to the surface of the bottom plate (21).

5. The cover plate structure according to claim 4, characterized in that, The bottom of the receiving groove (31) is a first annular structure, and the width f of the first annular structure satisfies: 0.5mm≤f≤1mm; And / or, along the direction perpendicular to the surface of the base plate (21), the groove depth g of the receiving groove (31) satisfies: 0.2mm≤g≤0.5mm.

6. The cover plate structure according to any one of claims 1-5, characterized in that, It also includes a conductive block (4), which is disposed on the side of the top cover (1) facing the outside of the cell, and N pillars (22) are all welded to the conductive block (4).

7. The cover plate structure according to claim 6, characterized in that, The conductive block (4) is provided with a relief groove (41), and the bottom of the relief groove (41) is provided with N third through holes (42). The N pillars (22) are respectively inserted at the N third through holes (42), and the N pillars (22) are all welded to the bottom of the relief groove (41).

8. The cover plate structure according to claim 7, characterized in that, The bottom of the clearance groove (41) is a second annular structure, and the width a of the second annular structure along the radial direction of the second annular structure satisfies: 0.5mm≤a≤1mm; And / or, along the axial direction of the column (22), the groove depth b of the clearance groove (41) satisfies: 0.2mm≤b≤0.5mm; And / or, along the axial direction of the column (22), the weld penetration depth c between the column (22) and the bottom of the relief groove (41) satisfies: 0.3mm≤c≤1mm.

9. The cover plate structure according to claim 6, characterized in that, The welding plate (3) and the base plate (21) are both made of the first material, the end of the column (22) away from the base plate (21) is made of the second material, and the conductive block (4) is made of the second material; And / or, the composite pole (2) is a pole formed by pressing.

10. A battery cell, characterized in that, It includes a housing and a cover structure as described in any one of claims 1-9, the cover structure covering the opening of the housing.

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