Battery cover plate and battery monomer

Abstract

The utility model relates to the technical field of lithium ion batteries, in particular to a battery cover plate and a battery monomer. The battery cover plate comprises a pole, a cover plate body and a connecting piece, the pole comprises a first step part, a second step part, a third step part and a fourth step part of which the cross sectional areas are sequentially reduced; the second step part and the third step part penetrate through the through hole of the cover plate body, and the fourth step part is welded with the hole wall of the welding hole of the connecting piece; the cover plate body is limited between the first step part and the connecting piece; the cross sections of the first step part, the second step part, the third step part and the fourth step part are elliptical or waist-shaped; the cross section area of the fourth step part is not less than 6mm < 2 >. According to the battery cover plate and the battery monomer, the problems that the over-current requirement and the strength requirement cannot be met due to the fact that most of the pole columns of the existing battery cover plate are circular, and the performance of the battery is easily damaged due to riveting vibration due to the fact that the pole columns are connected with the riveting blocks in a riveting manner are solved.

Description

Battery cover and battery cells Technical Field

[0001] This application relates to the field of lithium-ion battery technology, and in particular to a battery cover and a battery cell. Background Technology

[0002] With the increasing maturity of lithium-ion battery technology, lithium-ion batteries are widely used as power batteries in the field of electric vehicles. The cover plate of a lithium-ion battery is an important component of a lithium-ion power battery. It not only ensures the safety and reliability of the lithium-ion battery, but also facilitates the connection between the internal chemical system of the lithium-ion battery and the external module.

[0003] The existing battery cover includes a riveting block, an upper plastic, a cover body, and a lower plastic. The terminal passes through the riveting block, the upper plastic, the cover body, and the lower plastic in sequence. The terminal is riveted to the riveting block. However, the above assembly method of the cover makes it easy for riveting vibration to damage the battery performance, and the processing technology is complicated.

[0004] In addition, with the development of technology, people are becoming more and more eager for fast charging time for batteries. Currently, the blade battery itself is characterized by its thinness, and the terminals of its cover plate are mostly round, which cannot meet the overcurrent requirements and strength requirements. Summary of the Invention

[0005] The purpose of this application is to provide a battery cover and a battery cell, thereby solving the problems that the terminals of existing battery covers are mostly round, which cannot meet the requirements of overcurrent and strength, and that the terminals and the riveting block are riveted together, and the riveting vibration can easily damage the battery performance.

[0006] According to a first aspect of this application, a battery cover is provided, the battery cover comprising a terminal post, a cover body, and a connector; the terminal post comprises a first step portion, a second step portion, a third step portion, and a fourth step portion connected in sequence; the cross-sectional areas of the first step portion, the second step portion, the third step portion, and the fourth step portion decrease sequentially; the cover body is provided with a through hole for the second step portion and the third step portion to pass through, and the connector is provided with a welding hole for welding the fourth step portion; the second step portion and the third step portion pass through the through hole of the cover body, and the fourth step portion is welded to the wall of the welding hole of the connector; the cover body is positioned between the first step portion and the connector; the cross-sections of the first step portion, the second step portion, the third step portion, and the fourth step portion are all elliptical or oblong; the cross-sectional area of ​​the fourth step portion is ≥6mm². 2 .

[0007] In any of the above technical solutions, the thickness of the first step portion is ≥1.8mm.

[0008] In any of the above technical solutions, the surface formed at the connection between the third step and the fourth step is in contact with the connector; the battery cover also includes a sealing ring; the sealing ring is sleeved on the second step and the third step, and a portion of the sealing ring is press-fitted between the second step and the connector.

[0009] In any of the above technical solutions, the sealing ring further includes an inner ring portion, an outer ring portion, and an insulating rib; the insulating rib protrudes toward the first stepped portion relative to the inner ring portion and the outer ring portion; the insulating rib is disposed between the second stepped portion and the cover plate body, the inner ring portion is press-fitted between the second stepped portion and the connector, and the outer ring portion is press-fitted between the cover plate body and the connector.

[0010] In any of the above technical solutions, the lower surface of the second step portion is further aligned with the lower surface of the cover plate body, and the inner ring portion and the outer ring portion have the same thickness.

[0011] In any of the above technical solutions, the distance between the second step portion and the connector, and the distance between the cover plate body and the connector are both 0.5mm-1.2mm.

[0012] In any of the above technical solutions, the battery cover further includes a first plastic part; the first plastic part is sleeved on the connector and disposed between the cover body and the connector; the cover body includes a main body and a reinforcing part connected to each other, the reinforcing part protruding from the main body to the side opposite to the first step; the cross-sectional area of ​​the through hole provided in the main body is smaller than the cross-sectional area of ​​the through hole provided in the reinforcing part; the lower surface of the second step is aligned with the lower surface of the main body, the outer ring is press-fitted between the main body and the connector, and the distance between the main body and the connector is 0.5mm-1.2mm; the outer edge of the first plastic part is provided with an annular outer groove that mates with the reinforcing part, and the inner edge of the first plastic part is provided with an annular inner groove that mates with the connector.

[0013] In any of the above technical solutions, the second step portion is further defined as a waist-shaped columnar structure; both sides of the second step portion extending along its own long axis are planar.

[0014] In any of the above technical solutions, the battery cover further includes a second plastic part, the second plastic part including a side wall and a bottom wall, the first step portion being disposed within the installation space enclosed by the side wall and the bottom wall, the bottom wall being provided with a through hole for the second step portion to pass through; the side of the first step portion away from the second step portion is exposed to the outside of the second plastic part.

[0015] According to a second aspect of this application, a battery cell is provided, including a battery cover as described above; the terminal post is disposed in the middle of the battery cover; the battery cell includes a housing and two battery covers, the two covers being respectively connected to openings at both ends of the housing.

[0016] The battery cover of this application includes a terminal post, a cover body, and a connector. The terminal post includes a first stepped portion, a second stepped portion, a third stepped portion, and a fourth stepped portion connected in sequence; the cross-sectional areas of the first stepped portion, second stepped portion, third stepped portion, and fourth stepped portion decrease sequentially. The cover body has through holes for the second and third stepped portions to pass through, and the connector has a welding hole for welding the fourth stepped portion. The second and third stepped portions pass through the through holes in the cover body, and the fourth stepped portion is welded to the wall of the welding hole in the connector. The cover body is positioned between the first stepped portion and the connector. The cross-sections of the first, second, third, and fourth stepped portions are all elliptical or oblong, and the cross-sectional area of ​​the fourth stepped portion is ≥6mm². 2 .

[0017] Based on the above technical features, the beneficial effects of this application are as follows:

[0018] This application uses welding of the terminal post and connector to form a battery cover with the cover body, eliminating the riveting block in the prior art, that is, eliminating the riveting method in the prior art. This application not only simplifies the process, but also has a better assembly effect. Importantly, it will not cause the battery performance to be damaged by riveting vibration.

[0019] Furthermore, this application, by eliminating the riveting block, replaces the existing circular terminal post with an elliptical or waist-shaped terminal post. This maximizes the length of the terminal post in the battery cover, making its cross-sectional area larger than that of a circle. Thus, given the limited width of the battery cover, it increases the current-carrying area and improves the current-carrying capacity, enabling the battery cover with the aforementioned terminal post to meet the increasingly higher capacity and faster charging speed requirements of batteries. It also reduces the width of the terminal post in the battery cover, allowing the battery cover to be used in more applications. Moreover, the cross-sectional area of ​​the fourth step in this application is ≥6mm². 2 When the fourth step is welded to the electrode lug, the current carrying capacity and strength requirements are further improved.

[0020] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 shows a schematic diagram of the overall structure of a battery cell according to an embodiment of this application;

[0023] Figure 2 shows a top view of Figure 1;

[0024] Figure 3 shows a partially enlarged schematic diagram of the AA cross-sectional view in Figure 2;

[0025] Figure 4 shows a partially enlarged schematic diagram of the BB cross-sectional view in Figure 2;

[0026] Figure 5 shows a schematic diagram of the overall structure of the pole post according to an embodiment of this application;

[0027] Figure 6 shows a cross-sectional view of Figure 5;

[0028] Figure 7 shows a schematic diagram of the overall structure of the sealing ring according to an embodiment of this application;

[0029] Figure 8 shows a cross-sectional view of Figure 7;

[0030] Figure 9 shows a partial structural schematic diagram of Figure 1;

[0031] Figure 10 shows a schematic diagram of the overall structure of the battery cover plate according to an embodiment of this application.

[0032] Icons: 100-Pole post; 110-First step; 120-Second step; 130-Third step; 140-Fourth step; 200-Sealing ring; 210-Outer ring; 220-Inner ring; 230-Insulating rib; 300-Cover plate body; 310-Main body; 320-Reinforcing part; 400-Second plastic part; 410-Bottom wall; 420-Side wall; 500-Connector; 600-First plastic part; 610-Main body; 620-Insulating part; 630-Vertical rib; 700-Pole tab; 800-Pole assembly; 900-Outer shell. Detailed Implementation

[0033] The technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this application, but not all embodiments.

[0034] The components of the embodiments of this application described and shown in the accompanying drawings can be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of this application provided in the drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application.

[0035] Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0036] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0037] In the description of this application, 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 a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0038] Prior to this application, existing battery covers included a riveting block, an upper plastic layer, a cover body, and a lower plastic layer. The terminals passed sequentially through the riveting block, the upper plastic layer, the cover body, and the lower plastic layer, with the terminals riveted to the riveting block. However, this assembly method of the cover was prone to damage to battery performance due to riveting vibrations, and the manufacturing process was complex. Furthermore, with technological advancements, there is an increasing urgency for faster battery charging. Currently, blade batteries are inherently thin, and their cover terminals are mostly circular, which cannot meet overcurrent and strength requirements.

[0039] In view of this, the first aspect of this application provides a battery cover, thereby solving the above-mentioned technical problems existing in the prior art battery covers. The battery cover according to some embodiments of this application is described below with reference to Figures 1 to 10.

[0040] As shown in Figures 3, 4, and 5, the battery cover of this application includes a terminal post 100, a cover body 300 (e.g., a plain aluminum plate), and a connector 500 (e.g., a welding block). The terminal post 100 includes a first stepped portion 110, a second stepped portion 120, a third stepped portion 130, and a fourth stepped portion 140 connected in sequence; the cross-sectional areas of the first stepped portion 110, second stepped portion 120, third stepped portion 130, and fourth stepped portion 140 decrease sequentially; the cover body 300 has through holes through which the second stepped portion 120 and third stepped portion 130 pass, and the connector 500 has welding holes for welding the fourth stepped portion 140; the second stepped portion 120 and third stepped portion 130 pass through the through holes of the cover body 300, and the fourth stepped portion 140 is welded to the wall of the welding hole of the connector 500; the cover body 300 is positioned between the first stepped portion 110 and the connector 500. The cross-sections of the first step 110, the second step 120, the third step 130, and the fourth step 140 are all elliptical or waist-shaped.

[0041] In other words, this application uses the electrode post 100 and the connector 500 to weld together with the cover plate body 300 to form a battery cover plate, eliminating the riveting block in the prior art, that is, eliminating the riveting method in the prior art. This application not only simplifies the process, but also has a better assembly effect. More importantly, it will not cause the battery performance to be damaged by riveting vibration.

[0042] Furthermore, this application, by eliminating the riveting block, changes the existing circular terminal post to an elliptical or waist-shaped terminal post. This maximizes the length of the terminal post 100 in the battery cover, making its cross-sectional area larger than that of a circle. Thus, given the limited width of the battery cover, the current-carrying area of ​​the terminal post 100 is increased, and the current-carrying capacity is improved. This allows the battery cover with the aforementioned terminal post 100 to meet the increasingly higher capacity and faster charging speed requirements of batteries, while reducing the width of the terminal post 100 in the battery cover, enabling the battery cover to be used in more applications.

[0043] In the embodiments of this application, when the cross-section of the pole post 100 is elliptical, the major axis of the ellipse extends along the length direction of the cover plate body 300, and the minor axis of the ellipse extends along the width direction of the cover plate body 300. Therefore, the actual flow area that the pole post 100 with an elliptical cross-section can handle is maximized by utilizing the distance along the length direction of the cover plate body 300, and it also helps the pole post 100 extend along the length direction of the cover plate body 300, increasing the flow area of ​​the pole post 100. As shown in Figures 2, 5, and 6, when the cross-section of the pole post 100 is waist-shaped (racetrack-shaped), the length of the waist extends along the length direction of the cover plate body 300, and the width of the waist extends along the width direction of the cover plate body 300.

[0044] In addition, the cross-section of the pole post 100 is elliptical or waist-shaped. When the bottom of the pole post 100 is welded to the tab 700, and when the top of the pole post 100 is welded to the external busbar, the elliptical or waist-shaped cross-section has a larger cross-sectional area than the circular one, which further increases the flow area of ​​the pole post 100 and improves the flow capacity.

[0045] Preferably, in the embodiments of this application, as shown in FIG5, the first step portion 110, the second step portion 120, the third step portion 130, and the fourth step portion 140 are all waist-shaped columnar structures. The cross-sectional area of ​​the fourth step portion 140 is ≥6mm². 2 This configuration further enhances the current-carrying capacity and product strength when the fourth step 140 is welded to the electrode tab.

[0046] Preferably, in the embodiments of this application, the thickness of the first step portion 110 is ≥1.8mm. This configuration further improves the product strength when the first step portion 110 is welded to the external busbar.

[0047] Furthermore, in the embodiments of this application, the first step portion 110, the second step portion 120, the third step portion 130, and the fourth step portion 140, with gradually decreasing cross-sectional areas, constitute a stepped structural design that facilitates tight connection and positioning between different components. For example, as shown in Figures 3 and 4, the fourth step portion 140 is welded to the wall of the welding hole of the connector 500 to achieve electrical connection, and the surface formed at the connection between the third step portion 130 and the fourth step portion 140 is in contact with the connector 500. This design not only ensures the connection strength between the fourth step portion 140 and the connector 500 through welding, but also increases the contact area of ​​the contacting surface, improving the stability and reliability of the connection, thereby improving the strength and stability of the entire battery cover structure. In this example, the fourth step portion 140 is welded to the wall of the welding hole of the connector 500, and the welding melt depth is preferably the thickness of the fourth step portion 140.

[0048] Furthermore, to meet the assembly and insulation performance requirements of the battery cover, and to prevent the risk of air leakage due to poor welding between the terminal post 100 and the connector 500, this application also provides a sealing ring 200. As shown in Figures 3, 4, 7, and 8, the sealing ring 200 is fitted onto the second step portion 120 and the third step portion 130. A portion of the sealing ring 200 is press-fitted between the second step portion 120 and the connector 500.

[0049] Specifically, as shown in Figures 7 and 8, the sealing ring 200 includes an inner ring portion 220, an outer ring portion 210, and an insulating rib 230. The insulating rib 230 protrudes towards the first step portion 110 relative to the inner ring portion 220 and the outer ring portion 210. As shown in Figures 3 and 4, the insulating rib 230 is disposed between the second step portion 120 and the cover plate body 300, the inner ring portion 220 is press-fitted between the second step portion 120 and the connector 500, and the outer ring portion 210 is press-fitted between the cover plate body 300 and the connector 500. Thus, the inner ring portion 220 ensures a sealing effect between the connector 500 and the pole post 100, the outer ring portion 210 ensures a sealing effect between the connector 500 and the cover plate body 300, and the insulating rib 230 ensures an insulating effect between the pole post 100 and the cover plate body 300.

[0050] In the embodiments of this application, as shown in Figures 3, 4, 7, and 8, the lower surface of the second step portion 120 is aligned with the lower surface of the cover body 300, and the inner ring portion 220 and the outer ring portion 210 have the same thickness. This alignment of the lower surface of the second step portion 120 with the lower surface of the cover body 300 facilitates easier positioning and installation of the battery cover during assembly, reducing assembly errors and improving assembly efficiency. Furthermore, the equal thickness of the inner ring portion 220 and the outer ring portion 210 ensures uniform compression at different locations. When the sealing ring 200 is compressed, the uniform thickness allows the inner ring portion 220 and the outer ring portion 210 to provide uniform sealing pressure, thereby ensuring stable and reliable sealing performance of the entire sealing ring 200.

[0051] Preferably, the distance between the second step portion 120 and the connector 500, and the distance between the cover plate body 300 and the connector 500, are both 0.5mm-1.2mm. That is, the thickness of the third step portion 130 is equal to the thickness of the inner ring portion 220 and the outer ring portion 210 after compression, both being 0.5mm-1.2mm. Furthermore, the end face mates with the connector 500, positioning the connector 500 in the height direction.

[0052] Furthermore, to meet the assembly and insulation requirements of the battery cover, as shown in Figures 3 and 4, the battery cover of this application also includes a first plastic part 600. The first plastic part 600 is sleeved on the connector 500 and disposed between the cover body 300 and the connector 500.

[0053] Specifically, the cover plate body 300 includes a main body portion 310 and a reinforcing portion 320 connected to each other. The reinforcing portion 320 protrudes from the main body portion 310 toward the side opposite to the first step portion 110. The cross-sectional area of ​​the through hole provided in the main body portion 310 is smaller than the cross-sectional area of ​​the through hole provided in the reinforcing portion 320. The lower surface of the second step portion 120 is aligned with the lower surface of the main body portion 310. The outer ring portion 210 is press-fitted between the main body portion 310 and the connector 500. The distance between the main body portion and the connector 500 is 0.5mm-1.2mm. The outer edge of the reinforcing portion 320 is inserted into the outer casing 900 of the battery cell.

[0054] As shown in Figures 3 and 4, the outer edge of the first plastic part 600 is provided with an annular outer groove that mates with the reinforcing part 320, and the inner edge of the first plastic part 600 is provided with an annular inner groove that mates with the connecting part 500.

[0055] Preferably, as shown in Figures 3 and 4, the first plastic part 600 includes an insulating portion 620, a vertical rib 630, and a body portion 610 connected sequentially from top to bottom. The insulating portion 620 extends inward (towards the pole post 100) to insulate between the connector 500 and the body portion 310. The annular inner groove formed by the vertical rib 630 and the insulating portion 620 engages with the annular limiting groove formed by the connector 500. The body portion 610 extends outward (away from the pole post 100), with its extension length approaching that of the cover plate body 300. The annular outer groove formed by the vertical rib 630 and the body portion 610 engages with the annular limiting groove formed by the body portion 310 and the reinforcing portion 320. This configuration allows the inner annular groove to cooperate with the connector 500 and the outer annular groove to cooperate with the cover plate body 300, providing accurate positioning and installation space for the cover plate body 300, the first plastic part 600, and the connector 500. This ensures the connection accuracy between the cover plate body 300, the first plastic part 600, and the connector 500, thereby improving the assembly quality and stability of the entire battery cover.

[0056] Furthermore, it is worth mentioning that, as shown in Figures 5 and 6, the first step portion 110, the second step portion 120, the third step portion 130, and the fourth step portion 140 of this application are all waist-shaped columnar structures, and the two sides of the second step portion 120 extending along its own long axis are both flat. Thus, the flat sections of the two sides of the second step portion 120, in conjunction with the cover plate body, can prevent the pole post from rotating, further improving product performance.

[0057] In addition, as shown in FIG10, in this embodiment, a rectangular receiving space for assembling the electrode tab 700 is provided on the side of the connector 500 near the electrode assembly 800.

[0058] Furthermore, in order to meet the assembly and insulation performance requirements of the battery cover, as shown in Figures 3, 4 and 9, the battery cover of this application also includes a second plastic part 400. The second plastic part 400 includes a side wall 420 and a bottom wall 410. A first stepped portion 110 is disposed within the mounting space enclosed by the side wall 420 and the bottom wall 410. The bottom wall 410 is provided with a through hole for the second stepped portion 120 to pass through. The side of the first stepped portion 110 away from the second stepped portion 120 is exposed on the outside of the second plastic part 400.

[0059] In summary, this application uses the electrode post 100 and connector 500 to weld together with the second plastic part 400, cover plate body 300, first plastic part 600 and sealing ring 200 to form a battery cover plate, eliminating the riveting block in the prior art, that is, eliminating the riveting method in the prior art. This application not only simplifies the process, but also has a better assembly effect. More importantly, it will not cause the battery performance to be damaged by riveting vibration.

[0060] Furthermore, this application, by eliminating the riveting block, replaces the existing circular terminal post with an elliptical or waist-shaped terminal post. This maximizes the length of the terminal post 100 in the battery cover, making its cross-sectional area larger than that of a circle. Thus, given the limited width of the battery cover, it increases the current-carrying area of ​​the terminal post 100 and improves its current-carrying capacity. This allows the battery cover with the aforementioned terminal post 100 to meet the increasingly higher capacity and faster charging speed requirements of batteries, while reducing the width of the terminal post 100 in the battery cover, enabling the battery cover to be used in more applications. Moreover, the cross-sectional area of ​​the fourth step portion 140 in this application is ≥6mm². 2 When the fourth step 140 is welded to the electrode lug, the current carrying capacity and strength requirements are further improved.

[0061] In addition, the electrode post 100 of this application can be a copper-aluminum composite electrode post (copper and aluminum are connected in layers). The ratio of copper and aluminum in the copper-aluminum composite electrode post can be adjusted according to the needs, which makes it convenient to thicken the copper-aluminum composite electrode post in one go.

[0062] A second aspect of this application provides a battery cell, which includes the battery cover plate as described above. As shown in Figure 1, the terminal post 100 is disposed in the middle of the battery cover plate; the battery cell includes a housing 900 and two battery cover plates, which are respectively connected to the openings at both ends of the housing 900 (the battery cover plate at the bottom of Figure 1 is obscured due to viewing angle). That is, only one terminal post 100 is provided at one end of the battery cell, and the terminal post 100 is disposed in the middle of the battery cover plate. This facilitates the extension of the waist-shaped terminal post 100 along the length direction of the battery cover plate, further increasing the current-carrying area of ​​the terminal post 100 and improving the current-carrying capacity.

[0063] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The protection scope of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the scope of the technology disclosed in this application, or make equivalent substitutions for some of the technical features. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the protection scope of this application.

Claims

1. A battery cover, characterized in that, The battery cover includes a terminal post, a cover body, and a connector; the terminal post includes a first step, a second step, a third step, and a fourth step connected in sequence; the cross-sectional areas of the first step, the second step, the third step, and the fourth step decrease sequentially; the cover body has a through hole for the second step and the third step to pass through, and the connector has a welding hole for welding the fourth step; the second step and the third step pass through the through hole of the cover body, and the fourth step is welded to the wall of the welding hole of the connector; the cover body is positioned between the first step and the connector; the cross-sections of the first step, the second step, the third step, and the fourth step are all elliptical or oblong; the cross-sectional area of ​​the fourth step is ≥6mm². 2 .

2. The battery cover according to claim 1, characterized in that, The thickness of the first step is ≥1.8mm.

3. The battery cover according to claim 1, characterized in that, The surface formed at the connection between the third step and the fourth step fits into the connector; the battery cover also includes a sealing ring; the sealing ring is sleeved on the second step and the third step, and a portion of the sealing ring is press-fitted between the second step and the connector.

4. The battery cover according to claim 3, characterized in that, The sealing ring includes an inner ring portion, an outer ring portion, and an insulating rib; the insulating rib protrudes toward the first step portion relative to the inner ring portion and the outer ring portion; the insulating rib is disposed between the second step portion and the cover plate body, the inner ring portion is press-fitted between the second step portion and the connector, and the outer ring portion is press-fitted between the cover plate body and the connector.

5. The battery cover according to claim 4, characterized in that, The lower surface of the second step portion is aligned with the lower surface of the cover plate body, and the inner ring portion and the outer ring portion have the same thickness.

6. The battery cover according to claim 5, characterized in that, The distance between the second step and the connector, and the distance between the cover plate body and the connector are both 0.5mm-1.2mm.

7. The battery cover according to claim 5, characterized in that, The battery cover also includes a first plastic part; the first plastic part is sleeved on the connector and disposed between the cover body and the connector; the cover body includes a main body and a reinforcing part connected to each other, the reinforcing part protruding from the main body towards the side opposite to the first step; the cross-sectional area of ​​the through hole provided in the main body is smaller than the cross-sectional area of ​​the through hole provided in the reinforcing part; the lower surface of the second step is aligned with the lower surface of the main body, the outer ring is press-fitted between the main body and the connector, and the distance between the main body and the connector is 0.5mm-1.2mm; the outer edge of the first plastic part is provided with an annular outer groove that mates with the reinforcing part, and the inner edge of the first plastic part is provided with an annular inner groove that mates with the connector.

8. The battery cover according to claim 7, characterized in that, The second step is a waist-shaped columnar structure; both sides of the second step extending along its own long axis are flat.

9. The battery cover according to any one of claims 1-8, characterized in that, The battery cover also includes a second plastic part, which includes a side wall and a bottom wall. The first stepped portion is disposed within the installation space enclosed by the side wall and the bottom wall. The bottom wall is provided with a through hole for the second stepped portion to pass through. The side of the first stepped portion away from the second stepped portion is exposed to the outside of the second plastic part.

10. A single battery cell, characterized in that, The battery includes a battery cover plate as described in any one of claims 1-9; the terminal post is disposed in the middle of the battery cover plate; the battery cell includes a housing and two battery cover plates, the two cover plates being respectively connected to the openings at both ends of the housing.

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