End cover assembly and cylindrical battery
By setting bosses on the explosion-proof sheet and the lower end plate and controlling the welding area, the problem of high welding defect rate was solved, welding quality and conductivity were improved, and manufacturing costs were reduced.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-27
- Publication Date
- 2026-03-20
AI Technical Summary
In existing technologies, when welding the top cover, explosion-proof sheet, and lower end plate, the larger the welding surface, the more difficult it is to guarantee the welding quality, resulting in a high welding defect rate, which affects the battery's conductivity and increases manufacturing costs.
A downward-facing first boss is provided on the explosion-proof sheet, and an upward-facing second boss is provided on the lower end plate, which limits their mating surface, controls the welding area, and improves welding quality and conductivity.
By controlling the welding area, the welding qualification rate was improved, the manufacturing cost was reduced, and the conductivity of the end cap assembly was enhanced.
Smart Images
Figure CN224020866U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to cylindrical battery technical field especially relates to a end cover subassembly and cylindrical battery. BACKGROUND
[0002] In cylindrical battery, end cover subassembly has two functions of sealing and closing the upper end opening of battery shell and serving as battery anode; wherein, in the aspect of serving as battery anode, the electric conduction performance of end cover subassembly will directly affect the charge and discharge performance of battery, since the electric conduction part in end cover subassembly is usually formed by welding top cover, explosion-proof sheet and lower end plate in sequence from top to bottom, therefore the welding quality between top cover, explosion-proof sheet and lower end plate will directly affect the electric conduction performance of end cover subassembly.
[0003] However, in prior art, the technician always thinks that the larger the welding area is, the larger the contact connection area between explosion-proof sheet and lower end plate is, and the larger the current conduction area is, when welding top cover, explosion-proof sheet and lower end plate, especially when welding explosion-proof sheet and lower end plate, so the technician always sets the welding contact surface between explosion-proof sheet and lower end plate as large as possible.
[0004] Actually, it is not so, because with the increase of welding area, it is more difficult to guarantee the flatness of welding (not completely fit), therefore with the increase of welding area, the probability of problems such as explosion point and virtual welding in the welding process will be higher, which will increase the poor welding rate of end cover subassembly and increase the manufacturing cost of battery. CONTENT OF THE UTILITY MODEL
[0005] In order to solve the above technical defects existed in prior art, the utility model provides an end cover subassembly and cylindrical battery, by setting downward first boss on explosion-proof sheet, setting upward second boss on lower end plate, and limiting the size of the butt joint surface of first boss and second boss, the first boss only contacts with the second boss to control the size of welding area, so as to find a balance between improving the welding quality of explosion-proof sheet and lower end plate and improving the overcurrent performance of end cover subassembly.
[0006] The technical scheme for solving the above problems of the utility model is to provide an end cover subassembly, which comprises top cover sheet, explosion-proof sheet and lower end plate, the middle part of explosion-proof sheet is provided with downward first boss, the middle part of lower end plate is provided with upward second boss, the first boss and the second boss are in upward and downward contact and are welded and fixed, the diameter L1 of the lower end surface of the first boss is smaller than the diameter L2 of the upper end surface of the second boss, and the diameter L2 of the upper end surface of the second boss is 18-30% of the diameter L3 of the lower end plate.
[0007] Further, the diameter L1 of the lower end surface of the first boss is 0.36-0.6mm smaller than the diameter L2 of the upper end surface of the second boss.
[0008] Further, the diameter L1 of the lower end surface of the first boss is 8-18% of the diameter L4 of the explosion-proof sheet.
[0009] Further, a CID power-off protection groove is further arranged on the upper end surface of the second boss, and the CID power-off protection groove is a ring-shaped V-shaped groove or a plurality of V-shaped grooves equidistantly arranged along the circumferential direction.
[0010] Further, the distance L21 between the center of the CID power-off protection groove and the edge of the upper end surface of the second boss is 8%-18% of the diameter L2 of the upper end surface of the second boss.
[0011] Further, the thickness H1 of the second boss is 0.10-0.25mm, and the groove depth H2 of the CID power-off protection groove is 60%-70% of the thickness H1.
[0012] Further, the thickness H1 of the second boss is 0.10-0.25mm, and the thickness H1 of the second boss is 28-40% of the thickness H3 of the lower end plate.
[0013] Further, the included angle A between the side wall of the first boss and the upper end surface of the second boss is 35-65°.
[0014] Further, the end cover assembly further comprises an insulation layer arranged between the lower end plate and the explosion-proof sheet, and a through hole for inserting the first boss or the second boss is arranged in the middle part of the insulation layer, the thickness of the insulation layer is H4, and the distance from the lower end surface of the first boss to the explosion-proof sheet is H5, and H5 is 45-65% of H4.
[0015] The utility model also provides a cylindrical battery, the cylindrical battery includes electric core, cylindrical casing and the end cover assembly of any one of the above.
[0016] The utility model has the advantages of:
[0017] The first boss downwardly arranged on the explosion-proof sheet and the second boss upwardly arranged on the lower end plate are mutually butted and welded to be connected between the explosion-proof sheet and the lower end plate, so that the welding area between the explosion-proof sheet and the lower end plate is controlled to be in the optimal value, and the welding quality between the explosion-proof sheet and the lower end plate is improved.
[0018] In addition, although the explosion-proof sheet and the lower end plate are only mutually welded to be connected at the boss butt joint, the welding quality between the explosion-proof sheet and the lower end plate is effectively controlled, so that the actual flow capacity of the end cover assembly at the position where the explosion-proof sheet and the lower end plate are welded to be connected is improved, and the welding qualification rate is also improved, and the manufacturing cost is reduced. Attached Figure Description
[0019] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention. In these drawings, similar reference numerals are used to denote similar elements. The drawings described below are some embodiments of the present invention, but not all embodiments. Other drawings will be readily available to those skilled in the art based on these drawings without any inventive effort.
[0020] Figure 1 This is a cross-sectional view of the overall structure of the end cap assembly in this embodiment;
[0021] Figure 2 This is a cross-sectional view of the explosion-proof sheet in this embodiment;
[0022] Figure 3 This is a cross-sectional view of the lower end plate in this embodiment;
[0023] Figure 4 This is a cross-sectional view of the insulating layer in this embodiment.
[0024] 1-Top cover plate, 2-Explosion-proof plate, 21-First boss, 3-Lower end plate, 31-Second boss, 32-CID power failure protection groove, 4-Insulation layer. Detailed Implementation
[0025] The directional terms such as up, down, left, right, front, back, front, back, top, and bottom mentioned or possibly used in this specification are defined relative to the construction shown in the accompanying drawings. The terms "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively. These are relative concepts and may therefore vary depending on their location and usage. Therefore, these or other directional terms should not be interpreted as restrictive.
[0026] Please see Figures 1 to 4 This utility model discloses an end cap assembly for a 21 series cylindrical battery. The end cap assembly includes a top cover 1, an explosion-proof sheet 2, a lower end plate 3, and an insulating layer 4. The top cover 1, the explosion-proof sheet 2, and the lower end plate 3 are all conductive metal structures. The outer annular edge of the top cover 1 abuts downward against the outer annular edge of the explosion-proof sheet 2 and is welded to the explosion-proof sheet 2. To ensure the welding quality between the explosion-proof sheet 2 and the lower end plate 3, a first protrusion 21 is formed downward in the middle of the explosion-proof sheet 2, and a second protrusion 31 is formed upward in the middle of the lower end plate 3. The first protrusion 21 abuts downward against the first protrusion 21 and is welded to the first protrusion 21. The lower surface of the lower end plate 3 is electrically connected to the tab of the cell inside the cylindrical battery to form the positive terminal of the battery.
[0027] In addition, the lower end of the rupture disc 2 is provided with a clamping ring inclined to the center direction, and the insulating layer 4 is fixedly arranged at the lower surface of the rupture disc 2 by being clamped in the clamping ring; the lower end of the insulating layer 4 is also formed with a ring-shaped clamping groove, and the edge of the lower end plate 3 is clamped and mounted at the bottom of the insulating layer 4 by being inserted into the ring-shaped clamping groove; when inserted into the ring-shaped clamping groove, the lower end plate 3 further cooperates with the clamping ring to further clampingly fix the insulating layer 4, so as to prevent the insulating layer 4 and the lower end plate 3 from falling downward by themselves.
[0028] Furthermore, in the embodiment, in order to further improve the welding quality of the welded rupture disc 2 and the lower end plate 3, and to a certain extent, prevent the butt joint misalignment problem of the first boss 21 and the second boss 31, and ensure the flow performance of the end cover assembly between the rupture disc 2 and the lower end plate 3, the diameter L3 of the lower end plate 3 is 12.3 mm, the diameter L2 of the upper end surface of the second boss 31 is 2.9 mm, the diameter L1 of the lower end surface of the first boss 21 is 2.5 mm, and the diameter L4 of the rupture disc 2 is 14 mm.
[0029] However, in other embodiments, when the diameter L3 of the lower end plate 3 is 12.3 mm, the diameter L2 of the upper end surface of the second boss 31 can also be 2.214 mm or 2.952 mm or 3.69 mm, the diameter L1 of the lower end surface of the first boss 21 can be 1.614 mm or 2.592 mm or 3.33 mm, and the diameter L4 of the rupture disc 2 can be 13 mm or 18.5 mm or 20.175 mm.
[0030] In other embodiments, when L3 is 11.3 mm, the diameter L2 of the upper end surface of the second boss 31 can be 2.034 mm or 2.712 mm or 3.39 mm, the diameter L1 of the lower end surface of the first boss 21 can be 1.434 mm or 2.352 mm or 3.03 mm, and the diameter L4 of the rupture disc 2 can be 16.8 mm or 17.925 mm or 29.4 mm.
[0031] In other embodiments, when L3 is 13.3 mm, the diameter L2 of the upper end surface of the second boss 31 can be 2.394 mm or 3.192 mm or 3.99 mm, the diameter L1 of the lower end surface of the first boss 21 can be 2.034 mm or 2.592 mm or 3.63 mm, and the diameter L4 of the rupture disc 2 can be 20.2 mm or 25.425 mm or 32.4 mm.
[0032] Further, please refer to Figure 1 and Figure 3In the embodiment, the upper end surface of the second boss 31 is further provided with a CID power-off protection groove 32, the CID power-off protection groove 32 is a ring-shaped V-shaped groove, a circular area in the CID power-off protection groove 32 is a welding area, and the first boss 21 and the second boss 31 are connected only in the welding area to ensure that the CID power-off protection groove 32 can normally work.
[0033] In other embodiments, the CID power-off protection groove 32 can also be a plurality of arc-shaped V-shaped grooves distributed equidistantly along the circumcircle of the center of the upper end surface of the second boss 31.
[0034] Further, in order to ensure that the area of the welding area is reasonable and large enough to improve the overcurrent performance of the end cover assembly, and in order to avoid the situation that the edge stress of the second boss 31 is too concentrated due to the fact that the CID power-off protection groove 32 is too close to the edge of the upper end surface of the second boss 31, the breaking voltage is too large, the battery is not easy to break, and the safety performance of the battery is poor, the distance between the center of the CID power-off protection groove 32 and the edge of the upper end surface of the second boss 31 is L21, and the diameter of the upper end surface of the second boss 31 is L2. In the embodiment, L2 is 2.9 mm, and L21 is 0.232 mm.
[0035] However, in other embodiments, when L2 is 2.9 mm, L21 can also be 0.522 mm.
[0036] Further, in the embodiment, the depth H2 of the CID power-off protection groove 32 and the thickness H1 of the second boss 31 will directly affect the breaking voltage of the CID power-off protection groove 32, and in order to prevent the breaking voltage from being too large or too small, in the embodiment, the thickness H1 of the second boss 31 is 0.17 mm, and the groove depth H2 of the CID power-off protection groove 32 is 0.11 mm.
[0037] In other embodiments, the thickness of the second boss 31 can also be 0.1 mm or 0.25 mm, and the depth H2 of the CID power-off protection groove 32 can correspond to 0.06 mm or 0.07 mm, 0.15 mm or 0.175 mm.
[0038] At the same time, under the premise of ensuring that the structural strength of the lower end plate 3 is reasonable, in order to reduce the manufacturing difficulty of the lower end plate 3 and save material cost, in the embodiment, the thickness H3 of the lower end plate 3 is 0.5 mm.
[0039] In other embodiments, the thickness H3 of the lower end plate 3 can also be 0.425 mm or 0.61 mm.
[0040] Further, the included angle between the side wall of the first boss 21 and the upper end face of the second boss 31 is A, if A is too small, it will affect the effective welding area of the boss of the explosion-proof sheet 2, affect the flow capacity of the welding area, the heat production of the welding area, and the safety performance of the battery. If A is too large, it will increase the process difficulty of the explosion-proof sheet 2, such as the mold cannot be pulled out, etc. Therefore, in the embodiment, the included angle A between the side wall of the first boss 21 and the upper end face of the second boss 31 is 45°.
[0041] However, in other embodiments, the included angle A between the side wall of the first boss 21 and the upper end face of the second boss 31 can also be 35° or 65°.
[0042] Further, the insulating layer 4 is arranged between the lower end plate 3 and the explosion-proof sheet 2, the insulating layer 4 is made of insulating rubber material, the middle part of the insulating layer 4 is provided with a through hole for inserting the first boss 21 or the second boss 31, the thickness of the insulating layer 4 is H4, the distance from the lower end face of the first boss 21 to the explosion-proof sheet 2 is H5, H4 is also the distance between the lower end face of the main part of the explosion-proof sheet 2 and the upper end face of the main part of the lower end plate 3, and in order to prevent the current from directly flowing to the explosion-proof sheet 2 through the first boss 21 due to the second boss 31 being too close to the explosion-proof sheet 2, in the embodiment, H5 is 45% or 50% or 65% of H4.
[0043] The specific embodiment of the utility model further includes a cylindrical battery, the cylindrical battery includes a battery core, a cylindrical shell, and the end cover assembly of any one of the above embodiments, and the assembly mode between the end cover assembly, the battery core, and the cylindrical shell can refer to the prior art.
[0044] The above-mentioned matters not mentioned are applicable to the prior art.
[0045] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the utility model, and not to limit them. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the utility model.
Claims
1. An end cap assembly, the end cap assembly comprising a top cover plate (1), an explosion-proof plate (2), and a lower end plate (3), characterized in that, The explosion-proof plate (2) has a first protrusion (21) facing downward in the middle, and the lower end plate (3) has a second protrusion (31) facing upward in the middle. The first protrusion (21) and the second protrusion (31) are in contact with each other and welded together. The diameter L1 of the lower end face of the first protrusion (21) is smaller than the diameter L2 of the upper end face of the second protrusion (31). The diameter L2 of the upper end face of the second protrusion (31) is 18-30% of the diameter L3 of the lower end plate (3).
2. The end cap assembly as claimed in claim 1, characterized in that, The diameter L1 of the lower end face of the first boss (21) is 0.36-0.6 mm smaller than the diameter L2 of the upper end face of the second boss (31).
3. The end cap assembly as claimed in claim 1, characterized in that, The diameter L1 of the lower end face of the first boss (21) is 8-18% of the diameter L4 of the explosion-proof sheet (2).
4. The end cap assembly as claimed in claim 1, characterized in that, The upper surface of the second boss (31) is also provided with a CID power-off protection groove (32), which is an annular groove or a number of V-shaped grooves equidistantly arranged along the circumferential direction.
5. The end cap assembly as claimed in claim 4, characterized in that, The distance between the center of the CID power-off protection groove (32) and the edge of the upper surface of the second boss (31) is L21, and the diameter of the upper surface of the second boss (31) is L2, where L21 is 8-18% of L2.
6. The end cap assembly as claimed in claim 4, characterized in that, The thickness of the second boss (31) is H1, which is 0.10-0.25 mm, and the groove depth H2 of the CID power-off protection groove (32) is 60-70% of H1.
7. The end cap assembly as claimed in claim 1, characterized in that, The thickness of the second boss (31) is H1, which is 0.10-0.25 mm. The thickness H1 of the second boss (31) is 28-40% of the thickness H3 of the lower end plate (3).
8. The end cap assembly as claimed in claim 1, characterized in that, The angle A between the side wall of the first boss (21) and the upper end face of the second boss (31) is 35-65°.
9. The end cap assembly as claimed in claim 1, characterized in that, The end cap assembly further includes an insulating layer (4) spaced between the lower end plate (3) and the explosion-proof sheet (2). The insulating layer (4) has a through hole in the middle for the insertion of the first boss (21) or the second boss (31). The thickness of the insulating layer (4) is H4. The distance from the lower end face of the first boss (21) to the explosion-proof sheet (2) is H5, where H5 is 45-65% of H4.
10. A cylindrical battery, characterized in that, The cylindrical battery includes a cell, a cylindrical casing, and an end cap assembly as described in any one of claims 1-9.