Cover plate assembly and battery cell

Abstract

The utility model relates to the technical field of batteries, and discloses a cover plate assembly and a battery cell, and the cover plate assembly comprises a cover plate body, a pole assembly and a sealing plate. The cover plate body is provided with the welding through holes corresponding to the tabs, the bottom plate of the pole assembly extends to the position below the welding through holes, the bottom plate is provided with the receding parts, the tabs upwards penetrate through the bottom plate through the receding parts from the position below the bottom plate, the welding device penetrates through the welding through holes to weld the tabs and the bottom plate, observation and operation are convenient, and the welding efficiency is improved. Poor welding such as insufficient welding is effectively reduced; one end, far away from the column body in the first direction, of the bottom plate is larger than the welding through hole by a first size delta L, so that positioning of a welding tool is facilitated, and the welding area of the tab and the bottom plate is increased; the sealing plate is matched with the inclined surface of the welding through hole, so that the sealing plate can be conveniently mounted in the welding through hole, and the welding through hole can limit the sealing plate and prevent the sealing plate from falling to be in contact with the tab, so that the reliability of the cover plate assembly is improved, the assembly process is simple, and the battery cell assembly efficiency is favorably improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a cover plate assembly and a battery core. Background Art

[0002] The battery cell mainly includes a shell, a pole group arranged in the inner cavity of the shell, and a cover plate assembly arranged at the end of the shell. For a battery cell with pole ears at both ends, during the assembly process of the battery cell, it is necessary to first weld the pole ear at the first end of the pole group with the pole column on a cover plate assembly and then assemble it into the shell, and then assemble another cover plate assembly to the second end of the shell and weld it with the pole ear at the second end of the pole group. Among them, a connecting piece is usually arranged between the pole group and the cover plate body. The connecting piece is usually bent. During the assembly process of the battery cell, the connecting piece needs to be bent first and then installed into the battery cell. There are many steps and the battery cell assembly efficiency is low. In addition, in the prior art, the pole ear and the connecting piece are usually welded first, and then the connecting piece and the pole column are welded. During the welding process of the connecting piece and the pole column, laser penetration welding needs to be used for welding from above the pole column. The welding device of the welding equipment is located outside the battery cell, which is prone to poor welding such as cold welding and is difficult to operate. Utility Model Content

[0003] In view of this, the utility model provides a cover plate assembly and a battery cell to solve the problems of low battery cell assembly efficiency and easy occurrence of poor welding.

[0004] In the first aspect, the utility model provides a cover plate assembly, comprising: a cover plate body, provided with a pole through hole and a welding through hole, the welding through hole being suitable for corresponding to the pole ear on the pole group, the inner wall of the welding through hole being inclined, and the welding through hole being in the shape of a trumpet opening toward the upper side of the cover plate body; a pole assembly, comprising a column and a base plate, the column being inserted into the pole through hole, the base plate being connected to the lower end of the column and extending to the bottom of the welding through hole along a first direction, a yielding portion being constructed on the base plate, the yielding portion being suitable for the pole ear to pass through, the welding through hole being suitable for the welding device to pass through so as to weld the pole ear to the base plate, and along the first direction, the end of the base plate away from the column is larger than the welding through hole by a first dimension ΔL; a sealing plate, adapted to the welding through hole, the outer peripheral wall of the sealing plate being inclined and having the same inclination angle as the inner wall of the welding through hole, the outer peripheral wall of the sealing plate being welded to the inner wall of the welding through hole so as to seal the welding through hole.

[0005] Beneficial effects: By providing welding through-holes on the cover body corresponding to the tabs inside the battery cell, and extending the bottom plate of the terminal assembly below the welding through-holes, with a relief portion provided on the bottom plate for the tab to pass through, the tab can pass upward through the bottom plate from below the bottom plate, and the welding device can pass through the welding through-hole to weld the tab and the bottom plate, which is convenient for observation and operation, and can effectively reduce the occurrence of welding defects such as false soldering. Moreover, by setting that one end of the bottom plate away from the column body in the first direction is longer than the welding through-hole by a first dimension ΔL, that is, the bottom plate is longer, it provides a position for the welding tooling to position the tab, which is beneficial to increasing the welding area between the tab and the bottom plate, avoiding the problem of welding defects caused by insufficient welding area, ensuring the current-carrying capacity between the tab and the bottom plate, and thus improving the performance of the battery cell. At the same time, by providing the sealing plate to be welded and matched with the welding through-hole, it is convenient to seal the welding through-hole after the tab and the bottom plate are welded. The inner wall of the welding through-hole is inclined and in the shape of a flared opening facing the upper side of the cover body, which is convenient for the sealing plate with an inclined outer peripheral wall to be inserted into the welding through-hole, and the welding through-hole itself can limit the sealing plate through the inclined inner wall, so that the sealing plate just fits into the welding through-hole, preventing the sealing plate from further falling and contacting the tab, thereby improving the reliability of the cover assembly, and the assembly process is simple, which is beneficial to improving the assembly efficiency of the battery cell.

[0006] In an optional embodiment, in the first direction, the value range of the first dimension ΔL by which one end of the bottom plate away from the column body is longer than the welding through-hole is: ΔL≥0.5mm.

[0007] Beneficial effects: By setting the first dimension ΔL by which one end of the bottom plate away from the column body is longer than the welding through-hole to be greater than or equal to 0.5mm, the welding area between the bottom plate and the tab can be fully guaranteed, ensuring the reliability of welding.

[0008] In an optional embodiment, the value range of the dimension H1 of the bottom plate in the up-down direction is: H1≥1.5mm.

[0009] Beneficial effects: By setting the dimension H1 of the bottom plate in the up-down direction to be greater than or equal to 1.5mm, the bottom plate can be ensured to have sufficient strength, and further ensure the reliability of the welding between the bottom plate and the tab, preventing the bottom plate from being welded through during the welding process.

[0010] In an optional embodiment, the relief portion is located at the first side of the bottom plate in the second direction. In the second direction, the second side of the bottom plate is longer than the welding through-hole by a second dimension ΔW, where ΔW≥1mm, and the second direction is perpendicular to the first direction.

[0011] Beneficial effect: By setting the yielding portion at the first side of the base plate along the second direction, it is easy to process and form, and by setting the second side of the base plate longer than the welding through hole, the contact area between the base plate and the pole ear along the second direction can be increased. By setting the second side of the base plate to be longer than the welding through hole by a second dimension ΔW greater than or equal to 1mm, it is ensured that the base plate can provide sufficient welding area along the second direction, thereby further ensuring the flow area between the pole ear and the base plate, and improving the performance of the battery cell.

[0012] In an optional embodiment, the inclination angle θ of the inner wall of the welding through hole is in the range of: 45°-88°; and / or, the area occupied by the welding through hole on the upper surface of the cover plate body is S1, and the total area of ​​the upper surface of the cover plate body is S0, wherein 0.2≤S1 / S≤0.6.

[0013] Beneficial effect: By setting the inclination angle θ of the inner wall of the welding through hole to be in the range of 45° to 88°, it can be ensured that the angle between the inner wall of the welding through hole and the lower surface of the cover body is an acute angle, so that the inclined inner wall can provide an upward support force for the sealing plate, and it can also avoid that the opening area of ​​the upper side of the welding through hole is too large due to the inclination angle being too small, and occupying too much space on the cover body, thereby avoiding affecting the setting space of the pole assembly. By setting the ratio of the area S1 occupied by the welding through hole on the upper surface of the cover body to the area S0 of the upper surface of the cover body to be in the range of 0.2 to 0.6, it can be ensured that the welding through hole has a sufficient opening area, thereby ensuring that the welding device can fully weld the pole ear and the bottom plate through the welding through hole, ensuring that the product overcurrent requirements are met, and it can also avoid that the structural strength of the cover body is weakened due to the excessive opening area of ​​the welding through hole, thereby ensuring the reliability of the cover assembly.

[0014] In an optional embodiment, a chamfer is constructed at the upper edge of the welding through hole to form a first guide surface; a chamfer is constructed at the lower edge of the sealing plate to form a second guide surface, and the first guide surface and the second guide surface provide guidance for assembling the sealing plate into the welding through hole.

[0015] Beneficial effects: The first guide surface and the second guide surface provide guidance for the sealing plate to move into the welding through hole, ensuring that the sealing plate can be smoothly installed in the welding through hole, which is beneficial to improving work efficiency.

[0016] In an optional embodiment, the dimension t of the sealing plate along the up-down direction and the dimension T of the cover plate body along the up-down direction satisfy the relationship: 0.25T≤t≤0.8T; and / or, the upper surface of the sealing plate is located below the upper surface of the cover plate body, and the height difference a between the upper surface of the sealing plate and the upper surface of the cover plate body is in the range of 0.15mm≤a≤0.5mm.

[0017] Beneficial effect: By setting the dimension t of the sealing plate in the up-down direction and the dimension T of the cover plate body in the up-down direction to satisfy 0.25T≤t≤0.8T, it is possible to ensure that the sealing plate has sufficient strength and the reliability of the cover plate assembly, and to avoid the sealing plate from crushing the pole ear, thereby reducing the weight of the sealing plate as much as possible, reducing costs, and improving the energy density of the battery cell. By setting the upper surface of the sealing plate to be located below the upper surface of the cover plate body, and the upper surface of the sealing plate to be lower than the upper surface of the cover plate body, and the height difference a between the two to be between 0.15mm and 0.5mm, it is possible to ensure that the welding convex point formed by welding does not exceed the upper surface of the cover plate body, so as not to affect the assembly of the top patch on the upper surface of the cover plate body, and to ensure that the sealing plate has sufficient structural strength and improve the stability of the cover plate assembly.

[0018] In an optional embodiment, the cover plate assembly further includes: an insulating member disposed on the lower side of the sealing plate, the upper surface of the insulating member being in contact with the lower surface of the sealing plate, and the lower surface of the insulating member being spaced apart from the upper surface of the base plate.

[0019] Beneficial effect: By arranging an insulating member on the sealing plate and keeping the lower surface of the insulating member spaced from the upper surface of the bottom plate, a space is reserved for the tabs to prevent the tabs from being crushed and to prevent the tabs from directly contacting the sealing plate and causing a short circuit, thereby improving the safety of the battery cell.

[0020] In an optional embodiment, the distance between the lower surface of the insulating member and the upper surface of the base plate is H0, the dimension of the insulating member along the up and down directions is H2, the thickness of the pole ear is H3, and the distance between the lower surface of the insulating member and the upper surface of the pole ear is H4, wherein H0=H2+H3+H4, 3≤H4 / H3≤4.

[0021] Beneficial effect: The distance H0 between the lower surface of the insulating member and the upper surface of the base plate is equal to the sum of the thickness H2 of the insulating member, the thickness H3 of the bent portion of the tab and the distance H4 between the lower surface of the insulating member and the upper surface of the bent portion of the tab. By setting H4 / H3 to a value between 3 and 4, it can be ensured that the insulating member 7 will not crush the tab, and the internal space of the battery cell can be fully utilized, thereby improving the utilization rate of the internal space of the battery cell.

[0022] In a second aspect, the present utility model further provides an electric core, comprising: a housing with both ends along its length direction being open ends; a pole group disposed inside the housing, with pole tabs respectively at both ends of the pole group along its length direction; two sets of cover plate structures, with one set of the cover plate structures being provided at each of the two open ends of the housing, and one of the two sets of the cover plate structures being the above-mentioned cover plate assembly, and the pole column assembly on the cover plate assembly being welded to the corresponding pole tab. Since the electric core includes the cover plate assembly and has the same effects as the cover plate assembly, they will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific embodiments of the present utility model or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present utility model, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

[0024] Figure 1 Structural schematic diagram of a cover plate assembly without a sealing plate according to an embodiment of the present utility model;

[0025] Figure 2 is Figure 1 Structural schematic diagram of the bottom view of the cover plate assembly without a sealing plate shown in ;

[0026] Figure 3 is Figure 1 Cross-sectional view of the cover plate assembly without a sealing plate shown in ;

[0027] Figure 4 Structural schematic diagram of the cover plate assembly according to an embodiment of the present utility model;

[0028] Figure 5 is Figure 4 Partial enlarged schematic diagram of A in ;

[0029] Figure 6 is Figure 4 Partial enlarged schematic diagram of B in ;

[0030] Figure 7 Structural schematic diagram of an electric core according to an embodiment of the present utility model;

[0031] Figure 8 is Figure 7 Structural schematic diagram of the inverted electric core shown in ;

[0032] Figure 9 is Figure 7 Top view of the electric core shown in ;

[0033] Figure 10is Figure 9 A cross-sectional view in the C-C direction in

[0034] Figure 11 is Figure 10 A partial enlarged schematic view of the upper part of the battery cell in the cross-sectional view of the battery cell shown in

[0035] Figure 12 is Figure 11 A partial enlarged schematic view of F in

[0036] Figure 13 is Figure 10 A partial enlarged schematic view of the lower part of the battery cell in the cross-sectional view of the battery cell shown in

[0037] Figure 14 is Figure 9 A cross-sectional view in the D-D direction in

[0038] Figure 15 is Figure 9 A cross-sectional view in the E-E direction in

[0039] Figure 16 is Figure 7 The bottom view of the battery cell shown in

[0040] Figure 17 The structural schematic diagram of the second cover plate structure of the embodiment of the present utility model;

[0041] Figure 18 is Figure 17 The structural schematic diagram of the bottom view of the second cover plate structure shown in

[0042] Figure 19 is Figure 17 The cross-sectional view of the second cover plate structure shown in

[0043] Explanation of reference numerals:

[0044] 1. Housing; 2. Electrode group; 211. First tab; 221. Second tab; 202. Electrode group body; 3. Cover plate body; 301. Welding through hole; 302. First guiding surface; 304. Explosion-proof valve; 305. Liquid injection hole; 4. Electrode post assembly; 401. Column body; 402. Bottom plate; 403. Relief portion; 404. Riveting block; 5. Second electrode post assembly; 6. Sealing plate; 601. Second guiding surface; 7. Insulating part; 8. Sealing ring; 901. Upper plastic part; 902. Lower plastic part. Detailed implementation manners

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present utility model with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are some, but not all, of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0046] The following will describe the embodiments of the present utility model in conjunction with Figures 1 to 19 , the embodiments of the present utility model will be described.

[0047] According to an embodiment of the present utility model, on the one hand, a cover plate assembly is provided, as shown in Figures 1 to 6 . The cover plate assembly includes: a cover plate body 3, a pole column assembly 4, and a sealing plate 6. The cover plate body 3 is provided with a pole column through hole and a welding through hole 301. The welding through hole 301 is adapted to correspond to the pole tab on the pole group 2. The inner wall of the welding through hole 301 is inclined, and the welding through hole 301 is in the shape of a flared opening facing the upper side of the cover plate body 3; the pole column assembly 4 includes a column body 401 and a bottom plate 402. The column body 401 is inserted into the pole column through hole. The bottom plate 402 is connected to the lower end of the column body 401 and extends along a first direction to below the welding through hole 301. A relief portion 403 is formed on the bottom plate 402. The relief portion 403 is adapted to allow the pole tab to pass through. The welding through hole 301 is adapted to allow a welding device to pass through to weld the pole tab to the bottom plate 402. In the first direction, the end of the bottom plate 402 away from the column body 401 is larger than the welding through hole 301 by a first dimension ΔL; the sealing plate 6 is adapted to the welding through hole 301. The outer peripheral wall of the sealing plate 6 is inclined and has the same inclination angle as the inner wall of the welding through hole 301. The outer peripheral wall of the sealing plate 6 is welded to the inner wall of the welding through hole 301 to seal the welding through hole 301. Among them, the upper side refers to the side in the direction of "up" indicated by the arrow in Figures 3 to 4 ; the lower end refers to the end in the direction of "down" indicated by the arrow in Figures 3 to 4 ; the first direction refers to the "first direction" indicated by the arrow in Figures 1 to 5 , and the first direction is the same as the longer side of the cover plate body 3; the lower side refers to the direction of "down" indicated by the arrow in Figures 3 to 4 .

[0048] Applying the cover plate assembly of this embodiment, by providing welding through-holes 301 corresponding to the tabs inside the battery cell on the cover plate body 3, and the bottom plate 402 of the terminal assembly 4 extending below the welding through-holes 301, with a relief portion 403 provided on the bottom plate 402 for the tabs to pass through, it is realized that the tabs pass upward through the bottom plate 402 from below the bottom plate 402 via the relief portion 403, and the welding device passes through the welding through-holes 301 to weld the tabs and the bottom plate 402, which is convenient for observation and operation, and can effectively reduce the occurrence of welding defects such as poor soldering. Moreover, by setting that the end of the bottom plate 402 far from the column body 401 in the first direction is longer than the welding through-holes 301 by a first dimension ΔL, that is, the bottom plate 402 is longer, it provides a position for the welding tooling to position the tabs, which is beneficial to increasing the welding area between the tabs and the bottom plate 402, avoiding the problem of poor soldering caused by insufficient welding area, ensuring the current-carrying capacity between the tabs and the bottom plate 402, and thus improving the performance of the battery cell. At the same time, by setting the sealing plate 6 to be welded and matched with the welding through-holes 301, it is convenient to seal the welding through-holes 301 after the tabs and the bottom plate 402 are welded. The inner wall of the welding through-holes 301 is inclined and is in the shape of a flared opening facing the upper side of the cover plate body 3, which is convenient for the sealing plate 6 with an inclined outer peripheral wall to be inserted into the welding through-holes 301, and the welding through-holes 301 itself can limit the sealing plate 6 through the inclined inner wall, so that the sealing plate 6 just fits into the welding through-holes 301, preventing the sealing plate from further dropping and contacting the tabs, thereby improving the reliability of the cover plate assembly, and the assembly process is simple, which is beneficial to improving the assembly efficiency of the battery cell.

[0049] It should be noted that the inner wall of the welding through-holes 301 being inclined means that the inner wall of the welding through-holes 301 forms a non-90° angle with the lower surface of the cover plate body 3, and the inclination angle of the inner wall of the welding through-holes refers to the angle between the inner wall of the welding through-holes and the lower surface of the cover plate body 3; the outer peripheral wall of the sealing plate 6 being inclined means that the outer peripheral wall of the sealing plate 6 forms a non-90° angle with the upper surface of the sealing plate 6, and the inclination angle of the outer peripheral wall of the sealing plate 6 refers to the angle between the outer peripheral wall of the sealing plate 6 and the upper surface of the sealing plate 6; the outer peripheral wall of the sealing plate 6 having the same inclination angle as the inner wall of the welding through-holes 301 means that when the sealing plate 6 is assembled in the welding through-holes 301, at the corresponding positions of the two, the angle between the outer peripheral wall of the sealing plate 6 and the upper surface of the sealing plate 6 is equal to the angle between the inner wall of the welding through-holes 301 and the lower surface of the cover plate body 3, so that the outer peripheral wall of the sealing plate 6 can fit with the inner wall of the welding through-holes 301. The welding through-holes 301 are in the shape of a flared opening facing the upper side of the cover plate body 3, then along the up and down direction, the opening area at the upper end of the welding through-holes 301 is larger than that at the lower end, and the supporting force provided by the inclined surface of the welding through-holes 301 to the sealing plate 6 has an upward component force, which can realize the limitation of the sealing plate 6 and prevent the sealing plate 6 from further moving downward and passing through the welding through-holes 301.

[0050] It should be noted that the tab passes through the bottom plate 402 upward from below the bottom plate 402 through the relief portion 403, and then bends 90° toward the upper surface of the bottom plate 402. The welding device passes through the welding through-hole 301 to weld the tab and the bottom plate 402. The tab is pressed on the bottom plate 402 by the welding tooling for positioning and then welded. By setting the bottom plate 402 to be longer than the welding through-hole 301, it is convenient for the welding tooling to achieve positioning, thereby preventing the welding tooling from occupying the area on the tab for welding, realizing providing sufficient welding area for the welding of the tab and the bottom plate 402, thereby improving the welding quality and facilitating welding. The area of the bottom plate 402 below the welding through-hole 301 is welded to the tab. One end of the bottom plate 402 away from the tab in the first direction is connected to the column 401. Then, after the bottom plate 402 is welded to the tab, the electrical connection between the terminal assembly 4 and the electrode group 2 can be realized. Among them, the bottom plate 402 and the column 401 are integrally formed or welded together. Among them, the bottom plate 402 is equivalent to the connection piece in the traditional battery cell. The battery cell in this embodiment reduces the bending process of the connection piece and the bending process of the first tab 211, improves the production efficiency, and improves the space utilization rate inside the battery.

[0051] In one embodiment, in the first direction, the value range of the first dimension ΔL by which the end of the bottom plate 402 away from the column 401 is longer than the welding through-hole 301 is: ΔL≥0.5mm. It should be noted that if ΔL is less than 0.5mm, the size by which the bottom plate 402 is longer than the welding through-hole 301 is too small, and the area on the bottom plate 402 available for the welding tooling to position is insufficient. The welding tooling occupies the welding area of the tab, and the welding area of the tab is insufficient. There is a phenomenon of poor welding in the part of the tab close to the edge of the bottom plate 402 in the first direction. Therefore, by setting the first dimension ΔL by which the end of the bottom plate 402 away from the column 401 is longer than the welding through-hole 301 to be greater than or equal to 0.5mm, the welding area between the bottom plate 402 and the tab can be fully guaranteed, and the reliability of welding can be ensured.

[0052] In one embodiment, the value range of the dimension H1 of the bottom plate 402 in the up-down direction is: H1≥1.5mm. Among them, the up-down direction refers to the direction of "up and down" indicated by the arrow in Figure 6 The dimension of the bottom plate 402 in the up-down direction is the thickness of the bottom plate 402. If the dimension H1 of the bottom plate 402 in the up-down direction is less than 1.5mm, the thickness of the bottom plate 402 is too small and its own strength is insufficient. Therefore, by setting the dimension H1 of the bottom plate 402 in the up-down direction to be greater than or equal to 1.5mm, the bottom plate 402 can be ensured to have sufficient strength, and further the reliability of the welding between the bottom plate 402 and the tab can be ensured, and the bottom plate 402 can be prevented from being welded through during the welding process.

[0053] In one embodiment, further in combination with Figure 2 and Figure 14As shown, the clearance portion 403 is located at the first side of the bottom plate 402 along the second direction. In the second direction, the second side of the bottom plate 402 is larger than the welding through hole 301 by a second dimension ΔW, wherein ΔW ≥ 1 mm, and the second direction is perpendicular to the first direction. Figure 14 The "second direction" indicated by the middle arrow, the first direction and the second direction are two directions perpendicular to each other on the large surface of the cover body 3, the first direction is parallel to the longer side on the large surface of the cover body 3, and the second direction is parallel to the shorter side; the first side and the second side are two side sides on the bottom plate 402 located on opposite sides of the second direction, that is, two relatively longer sides; the welding through hole 301 is in the shape of an elongated strip, and its size along the first direction is larger than its size along the second direction; along the second direction, the second side of the bottom plate 402 is more than the welding through hole 301 by a second size ΔW, which means that the distance between an edge of the bottom plate 402 on the second side of the second direction on the orthographic projection of the cover body 3 and an edge of the welding through hole 301 on the second side of the second direction is ΔW. The making way portion 403 is formed by partially recessing a portion of the first side edge of the bottom plate 402 along the second direction toward the direction close to the second side edge. By arranging the making way portion 403 at the first side edge of the bottom plate 402 along the second direction, processing and forming are facilitated. By arranging the second side edge of the bottom plate 402 to be longer than the welding through hole 301, the contact area between the bottom plate 402 and the pole ear along the second direction can be increased. By arranging the second side edge of the bottom plate 402 to be longer than the welding through hole 301 by a second dimension ΔW greater than or equal to 1 mm, it is ensured that the bottom plate 402 can provide sufficient welding area along the second direction, thereby further ensuring the flow area between the pole ear and the bottom plate 402, and improving the performance of the battery cell.

[0054] In one embodiment, the value range of the inclination angle θ of the inner wall of the welding through hole 301 is: 45°-88°. It should be noted that the inclination angle θ of the inner wall of the welding through hole 301 refers to the angle between the inner wall of the welding through hole 301 and the lower surface of the cover body 3. By setting the inclination angle θ of the inner wall of the welding through hole 301 to a value in the range of 45° to 88°, it can be ensured that the angle between the inner wall of the welding through hole 301 and the lower surface of the cover body 3 is an acute angle, so that the inclined inner wall can provide an oblique upward support force to the sealing plate 6, and it can also avoid that the opening area on the upper side of the welding through hole 301 is too large due to the inclination angle being too small, thereby occupying too much space on the cover body 3, thereby avoiding affecting the setting space of the pole assembly 4.

[0055] It should be noted that the welding through hole 301 is strip-shaped, so the inner wall of the welding through hole 301 has four inclined surfaces. Correspondingly, the outer peripheral surface of the sealing plate 6 has four side surfaces. The inclination angles of the corresponding side surfaces of the sealing plate 6 are the same as those of the inclined surfaces of the inner wall of the welding through hole 301. The side surfaces on the outer peripheral side of the sealing plate 6 and the inclined surfaces of the inner wall of the welding through hole 301 are laser welded to form a sealing surface, realizing the sealing of the welding through hole 301 by the sealing plate 6.

[0056] In one embodiment, the area occupied by the welding through hole 301 on the upper surface of the cover plate body 3 is S1, and the total area of the upper surface of the cover plate body 3 is S0, where 0.2 ≤ S1 / S ≤ 0.6. Here, the upper surface refers to the surface in the direction of "up" indicated by the arrow in Figure 3 the middle; S1 is the opening area of the welding through hole 301 on the cover plate body 3; the area S0 of the upper surface of the cover plate body 3 refers to the area enclosed by the outer contour of the cover plate body 3. If S1 / S0 is less than 0.2, the opening area of the welding through hole 301 is too small, which is not convenient for operating the welding of the internal tab of the battery cell and the bottom plate 402, resulting in insufficient welding and unable to meet the over-current requirement of the product; if S1 / S0 is greater than 0.6, the opening area of the welding through hole 301 is too large, resulting in too little remaining solid part of the cover plate body 3 and insufficient strength of the cover plate body 3. Therefore, by setting the ratio between the area S1 occupied by the welding through hole 301 on the upper surface of the cover plate body 3 and the area S0 of the upper surface of the cover plate body 3 to be within the range of 0.2 to 0.6, it can not only ensure that the welding through hole 301 has sufficient opening area, so as to ensure that the welding device can fully weld when welding the tab and the bottom plate 402 through the welding through hole 301 and meet the over-current requirement of the product, but also avoid weakening the structural strength of the cover plate body 3 due to the too large opening area of the welding through hole 301, thus ensuring the reliability of the cover plate assembly.

[0057] In one embodiment, a chamfer is formed at the upper side edge of the welding through hole 301 to form a first guiding surface 302; a chamfer is formed at the lower side edge of the sealing plate 6 to form a second guiding surface 601. The first guiding surface 302 and the second guiding surface 601 provide guidance for the assembly of the sealing plate 6 into the welding through hole 301. The first guiding surface 302 is formed on the edge where the lower surface of the cover plate body 3 intersects with the inner wall of the welding through hole 301, and the second guiding surface 601 is formed on the edge where the lower surface of the sealing plate 6 intersects with its circumferential surface. When the sealing plate 6 is assembled into the welding through hole 301, the sealing plate 6 is inserted into the welding through hole 301 from the upper side of the cover plate body 3 downward. The first guiding surface 302 and the second guiding surface 601 provide guidance for the movement of the sealing plate 6 into the welding through hole 301, ensuring that the sealing plate 6 can be smoothly inserted into the welding through hole 301, which is beneficial to improving work efficiency.

[0058] In one embodiment, further in combination withFigure 4 and Figure 12 As shown in Figure 4 and Figure 12 , the relationship between the dimension t of the sealing plate 6 in the up - down direction and the dimension T of the cover plate body 3 in the up - down direction satisfies the formula: 0.25T ≤ t ≤ 0.8T. Here, the up - down direction refers to the direction of "up - down" indicated by the arrow. The dimension of the sealing plate 6 in the up - down direction is the thickness of the sealing plate 6, and the dimension of the cover plate body 3 in the up - down direction is the thickness of the cover plate body 3. If t is less than 0.25T, the thickness of the sealing plate 6 is too small relative to the thickness of the cover plate body 3, the structural strength of the sealing plate 6 is weak, a weak area is formed at this place, and it is easy to be damaged from this place, affecting the safety of the battery cell; if t is greater than 0.8T, the thickness of the sealing plate 6 is too large relative to the thickness of the cover plate body 3. After the sealing plate 6 is assembled into the welding through - hole 301, the sealing plate 6 is too close to the tab, there is a risk of pressing the tab, and the weight of the sealing plate 6 is too large, increasing the cost. Therefore, by setting the relationship between the dimension t of the sealing plate 6 in the up - down direction and the dimension T of the cover plate body 3 in the up - down direction to satisfy 0.25T ≤ t ≤ 0.8T, it can not only ensure that the sealing plate 6 has sufficient strength and ensure the reliability of the cover plate assembly, but also avoid pressing the tab by the sealing plate 6, reduce the weight of the sealing plate 6 as much as possible, reduce the cost, and improve the energy density of the battery cell.

[0059] In one embodiment, the upper surface of the sealing plate 6 is located below the upper surface of the cover plate body 3, and the value range of the height difference a between the upper surface of the sealing plate 6 and the upper surface of the cover plate body 3 is: 0.15mm ≤ a ≤ 0.5mm. It should be noted that the sealing plate 6 is welded to the inner wall of the welding through - hole 301, and the welding is operated from above the cover plate body 3. The welding device welds along the gap between the sealing plate 6 and the welding through - hole 301 and forms a welding bump on the upper side of the sealing plate 6. By setting the upper surface of the sealing plate 6 to be located below the upper surface of the cover plate body 3, and the upper surface of the sealing plate 6 is lower than the upper surface of the cover plate body 3, and the height difference a between the two is within the range of 0.15mm to 0.5mm, it can not only ensure that the welding bump formed by welding does not protrude above the upper surface of the cover plate body 3 so as not to affect the assembly of the top patch on the upper surface of the cover plate body 3, but also ensure that the sealing plate 6 has sufficient structural strength and improve the stability of the cover plate assembly.

[0060] It should be noted that if the height difference a between the upper surface of the sealing plate 6 and the upper surface of the cover plate body 3 is less than 0.15mm, the height difference between the two is too small, and the welding bump formed by welding will be higher than the upper surface of the cover plate body 3, thus affecting the assembly of the top patch on the upper surface of the cover plate body 3; if the height difference a between the upper surface of the sealing plate 6 and the upper surface of the cover plate body 3 is greater than 0.5mm, the height difference between the two is too large, resulting in a decrease in the thickness of the sealing plate 6, thus affecting the structural strength of the sealing plate 6 and the stability is poor.​​​​

[0061] By setting the matching parameters of the welding through-hole 301 and the sealing plate 6 and the parameters of the sealing plate 6 in this embodiment, the reliability of the welding of the sealing plate 6 and the cover body 3 is ensured, and the performance of the battery cell is improved.

[0062] In one embodiment, the cover assembly further includes: an insulating member 7 disposed on the lower side of the sealing plate 6. The upper surface of the insulating member 7 is attached to the lower surface of the sealing plate 6, and the lower surface of the insulating member 7 is spaced apart from the upper surface of the bottom plate 402. Herein, the lower side refers to the side in the direction of "down" indicated by the arrow in Figure 4 ; the lower surface refers to the surface in the direction of "down" indicated by the arrow in Figure 4 ; the upper surface refers to the surface in the direction of "up" indicated by the arrow in Figure 4 . The lower side of the sealing plate 6 faces the electrode group 2 inside the battery cell and is relatively close to the tab and the bottom plate 402. By providing the insulating member 7 on the sealing plate 6 and keeping the lower surface of the insulating member 7 spaced apart from the upper surface of the bottom plate 402, a receiving space is reserved for the tab, preventing the tab from being crushed and preventing the tab from coming into direct contact with the sealing plate 6 to cause a short circuit, thereby improving the safety of the battery cell.

[0063] In one embodiment, further in combination with Figure 4 and Figure 14 as shown, the distance between the lower surface of the insulating member 7 and the upper surface of the bottom plate 402 is H0, the dimension of the insulating member 7 in the up-and-down direction is H2, the thickness of the tab is H3, and the distance between the lower surface of the insulating member 7 and the upper surface of the tab is H4. Herein, H0 = H2 + H3 + H4, and 3 ≤ H4 / H3 ≤ 4. Herein, the up-and-down direction refers to the direction of "up and down" indicated by the arrow in Figure 4 and Figure 14 . The tab passes upward through the bottom plate 402 from the lower side of the bottom plate 402 and then bends toward the upper surface of the bottom plate 402. The bent portion is located between the lower surface of the insulating member 7 and the upper surface of the bottom plate 402, and there is a gap in the up-and-down direction between the upper surface of the bent portion and the insulating member 7, and this gap is H4 to avoid the insulating member 7 from crushing the tab. If H4 / H3 is less than 3, the distance between the insulating member 7 and the tab is too small, and there is a risk of crushing the tab; if H4 / H3 is greater than 4, the distance between the insulating member 7 and the tab is too large, and the utilization rate of the internal space of the battery cell is relatively low. Therefore, the distance H0 between the lower surface of the insulating member 7 and the upper surface of the bottom plate 402 is equal to the sum of the thickness H2 of the insulating member 7, the thickness H3 of the bent portion of the tab, and the distance H4 between the lower surface of the insulating member 7 and the upper surface of the bent portion of the tab. At the same time, by setting H4 / H3 to take values between 3 and 4, it can not only ensure that the insulating member 7 does not crush the tab, but also make full use of the internal space of the battery cell and improve the utilization rate of the internal space of the battery cell.

[0064] In one embodiment, the terminal assembly 4 further includes a riveting block 404 disposed on the upper side of the cover plate body 3. After the column body 401 passes through the terminal through-hole from the lower side of the cover plate body 3, the upper end of the column body 401 is riveted to the riveting block 404, thereby realizing the relative fixation of the column body 401 and the bottom plate 402 to the cover plate body 3.

[0065] In one embodiment, the cover plate assembly further includes a sealing ring 8 sleeved on the outer peripheral side of the column body 401 and located between the column body 401 and the cover plate body 3 to ensure the sealing between the column body 401 and the cover plate body 3; an upper plastic part 901 disposed between the riveting block 404 and the upper surface of the cover plate body 3 to ensure insulation between the terminal assembly 4 and the upper surface of the cover plate body 3; a lower plastic part 902 disposed between the cover plate body 3 and the electrode group 2. The upper side of the lower plastic part 902 is attached to the lower surface of the cover plate body 3 and the lower side abuts against a part of the electrode group body 202 to ensure insulation between the cover plate body 3 and the electrode group 2. A part of the structure on the lower plastic part 902 extends into the space between the bottom plate 402 and the cover plate body 3 to ensure insulation between the terminal assembly 4 and the lower surface of the cover plate body 3. By providing the sealing ring 8, the upper plastic part 901 and the lower plastic part 902 between the cover plate body 3 and the terminal assembly 4, the insulation and sealing between the terminal assembly 4 and the cover plate body 3 are ensured.

[0066] Preferably, the cover plate body 3 is a light aluminum plate, the upper plastic part 901 is an upper plastic, and the lower plastic part 902 is a lower plastic; the sealing plate 6 is made of aluminum, with a light weight and low cost.

[0067] According to an embodiment of the present invention, on the other hand, a battery cell is also provided, as Figures 7 to 19 shown. The battery cell includes a housing 1, an electrode group 2, and two sets of cover plate structures. Both ends of the housing 1 in its length direction are open ends; the electrode group 2 is disposed inside the housing 1, and both ends of the electrode group 2 in its length direction respectively have electrode tabs; one set of cover plate structures is provided at each of the two open ends of the housing 1, and one of the two sets of cover plate structures is the above-mentioned cover plate assembly, and the terminal assembly 4 on the cover plate assembly is welded to the corresponding electrode tab. The electrode group 2 is composed of an electrode group body 202 and two electrode tabs, and the two electrode tabs are a first electrode tab 211 and a second electrode tab 221. One end of the electrode group 2 in its length direction is provided with the first electrode tab 211 and the other end is provided with the second electrode tab 221. Among them, the length directions of the housing 1 and the electrode group 2 both refer to Figure 7 the "up and down" direction indicated by the arrow in

[0068] It should be noted that the battery cell has pole ears at both ends, and one of the cover structures at both ends of the battery cell is the above-mentioned cover assembly, that is, a pole assembly 4 is arranged on the cover body 3 and a welding through hole 301 is opened as a channel for welding the bottom plate 402 and the pole ear, which is called the first cover structure, and the pole assembly 4 in the first cover structure is the first pole assembly; the other cover structure is a common cover structure, that is, a second pole assembly 5 and an explosion-proof valve 304 and an injection hole 305 are arranged on the cover body 3 to form a second cover structure. During the battery cell assembly process, the second pole ear 221 of the pole group 2 is first welded to the second pole column assembly 5 on the second cover plate structure, so that the pole group 2 and the second cover plate structure are assembled together, and then assembled into the shell 1 together, and the second cover plate structure is located at one end of the shell 1; then the first cover plate structure (i.e. the above-mentioned cover plate assembly) is assembled at the other end of the shell 1, and the first pole ear 211 vertically passes through the yield portion 403 on the bottom plate 402 and then bends 90° to fit with the upper surface of the bottom plate 402, and the welding device passes through the welding through hole 301 to weld the first pole ear 211 and the bottom plate 402; after the insulating member 7 and the sealing plate 6 are assembled into one, they are placed at the welding through hole 301, the insulating member 7 faces the inside of the battery cell, and the sealing plate 6 is welded to the inner wall of the welding through hole 301 to achieve sealing.

[0069] Among them, one of the first pole ear 211 and the second pole ear 221 is a positive pole ear and the other is a negative pole ear, one of the pole column assembly 4 (first pole column assembly) and the second pole column assembly 5 is a positive pole column assembly and the other is a negative pole column assembly, the positive pole ear corresponds to the positive pole column, and the negative pole ear corresponds to the negative pole column. Preferably, the pole column assembly 4 is a positive pole column.

[0070] Although the embodiments of the present invention are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A cover plate assembly, characterized in that: include: The cover plate body is provided with a pole through hole and a welding through hole, wherein the welding through hole is suitable for corresponding to the pole ear on the pole group, the inner wall of the welding through hole is inclined, and the welding through hole is in a trumpet shape opening toward the upper side of the cover plate body; A pole assembly, comprising a column and a bottom plate, wherein the column is inserted into the pole through hole, the bottom plate is connected to the lower end of the column and extends to below the welding through hole along a first direction, a clearance portion is configured on the bottom plate, the clearance portion is suitable for the pole ear to pass through, the welding through hole is suitable for the welding device to pass through, so as to weld the pole ear to the bottom plate, and along the first direction, one end of the bottom plate away from the column is larger than the welding through hole by a first dimension ΔL; A sealing plate is adapted to the welding through hole, the outer peripheral wall of the sealing plate is inclined and has the same inclination angle as the inner wall of the welding through hole, and the outer peripheral wall of the sealing plate is welded to the inner wall of the welding through hole to seal the welding through hole.

2. The cover plate assembly according to claim 1, characterized in that: In the first direction, a first dimension ΔL which is larger than the welding through hole at one end of the bottom plate away from the column has a value range of ΔL≥0.5 mm.

3. The cover plate assembly according to claim 1, characterized in that: The dimension H1 of the bottom plate in the up-down direction has a value range of H1 ≥ 1.5 mm.

4. The cover plate assembly according to claim 1, characterized in that: The evacuation portion is located at a first side of the bottom plate along a second direction. In the second direction, the second side of the bottom plate is larger than the welding through hole by a second dimension ΔW, wherein ΔW≥1mm, and the second direction is perpendicular to the first direction.

5. The cover plate assembly according to claim 1, characterized in that: The value range of the inclination angle θ of the inner wall of the welding through hole is: 45°-88°; And / or, the area occupied by the welding through hole on the upper surface of the cover plate body is S1, and the total area of ​​the upper surface of the cover plate body is S0, wherein 0.2≤S1 / S≤0.

6.

6. The cover plate assembly according to claim 1, characterized in that: The upper edge of the welding through hole is chamfered to form a first guide surface; the lower edge of the sealing plate is chamfered to form a second guide surface, and the first guide surface and the second guide surface provide guidance for assembling the sealing plate into the welding through hole.

7. The cover plate assembly according to claim 1, characterized in that: The dimension t of the sealing plate in the up-down direction and the dimension T of the cover plate body in the up-down direction satisfy the relationship: 0.25T≤t≤0.8T; And / or, the upper surface of the sealing plate is located below the upper surface of the cover body, and the height difference a between the upper surface of the sealing plate and the upper surface of the cover body is in the range of 0.15 mm ≤ a ≤ 0.5 mm.

8. The cover plate assembly according to any one of claims 1 to 7, characterized in that: The cover plate assembly further includes: an insulating member disposed on the lower side of the sealing plate, wherein the upper surface of the insulating member is in contact with the lower surface of the sealing plate, and the lower surface of the insulating member is spaced apart from the upper surface of the bottom plate.

9. The cover plate assembly according to claim 8, characterized in that: The distance between the lower surface of the insulating member and the upper surface of the base plate is H0, the dimension of the insulating member along the up and down direction is H2, the thickness of the pole ear is H3, and the distance between the lower surface of the insulating member and the upper surface of the pole ear is H4, wherein H0=H2+H3+H4, 3≤H4 / H3≤4.

10. A battery cell, characterized in that: include: The shell has open ends at both ends along its length direction; A pole group is arranged inside the shell, and the pole group has pole ears at both ends along the length direction thereof; Two groups of cover plate structures, one group of the cover plate structures is arranged at each of the two open ends of the shell, one of the two groups of the cover plate structures is the cover plate assembly described in any one of claims 1 to 9, and the pole assembly on the cover plate assembly is welded to the pole ear corresponding thereto.

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