Battery cell and battery pack

Abstract

The utility model relates to the technical field of batteries, and discloses a battery cell and a battery pack. The battery cell comprises a cover plate, a pole group and a connecting sheet. The cover plate is provided with poles and a welding through hole, and two tabs corresponding to each pole are arranged on one side, close to the poles, of the pole group; the connecting piece comprises a pole connecting part, a tab connecting part and a reinforcing rib, the pole connecting part is welded with the pole, the tab connecting part is welded with the tab through the welding through hole, the reinforcing rib is arranged on any surface of the tab connecting part along the thickness direction of the tab connecting part, and at least one surface of the reinforcing rib is not coplanar with the tab connecting part; the reinforcing rib extends along the length direction of the tab connecting part to divide the tab connecting part into two tab connecting subareas, and the two tab connecting subareas are respectively used for connecting one tab. When the connecting piece and the tab are welded, zero-clearance contact between the connecting piece and the tab can be ensured only by means of the structural strength of the connecting piece, the welding effect is ensured, the space is saved, and the space utilization rate in the height direction of the battery cell is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a battery cell and a battery pack. Background Art

[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.

[0003] The connecting piece in the battery cell plays a role in conducting the electric energy of the electrode group to the electrode post. During the assembly process of the battery cell, it is necessary to weld the connecting piece and the electrode tab of the electrode group.

[0004] In the traditional battery cell solution, when welding the electrode tab and the connecting piece, it is necessary to use an auxiliary tooling to press the upper part of the electrode tab to play a supporting role, so that the connecting piece and the electrode tab are in zero-gap contact, thereby ensuring the welding effect. However, since the auxiliary tooling occupies a certain space, the space utilization rate in the height direction of the battery cell is low. Summary of the Utility Model

[0005] In view of this, the utility model provides a battery cell and a battery pack to solve the problem of low space utilization rate in the height direction of the battery cell.

[0006] In a first aspect, the utility model provides a battery cell, including a cover plate, an electrode group and a connecting piece. The cover plate is provided with an electrode post and a welding through hole; the electrode group is arranged inside the cover plate, and two electrode tabs are provided corresponding to each electrode post on the side of the electrode group close to the electrode post; the connecting piece is arranged between the cover plate and the electrode group, and the connecting piece includes an electrode post connecting portion, an electrode tab connecting portion and a reinforcing rib. The electrode post connecting portion is welded to the electrode post, and the electrode tab connecting portion is welded to the electrode tab through the welding through hole. Along the thickness direction of the electrode tab connecting portion, the reinforcing rib is arranged on any surface of the electrode tab connecting portion, and at least one of the inner surface and the outer surface of the reinforcing rib is not coplanar with the electrode tab connecting portion; the reinforcing rib extends along the length direction of the electrode tab connecting portion, dividing the electrode tab connecting portion into two electrode tab connecting zones, and the two electrode tab connecting zones are respectively used for connecting one electrode tab.

[0007] Beneficial Effects: For the battery cell provided by the utility model, a reinforcing rib is arranged on the electrode tab connecting portion of the connecting piece. Since at least one of the inner surface and the outer surface of the reinforcing rib is not coplanar with the electrode tab connecting portion, the reinforcing rib can play a role in strengthening the structure of the connecting piece itself. When using a connecting piece with such a structure to weld the connecting piece and the electrode tab, there is no need to set up an auxiliary tooling for support. Only relying on the structural strength of the connecting piece itself can ensure zero-gap contact between the connecting piece and the electrode tab, ensure the welding effect, save space and improve the space utilization rate in the height direction of the battery cell. At the same time, the cover plate is provided with a welding through hole, and the connecting piece and the electrode tab are welded through the welding through hole. Since the cover plate is only provided with one welding through hole, the continuity of welding can be ensured, one welding process can be reduced, and the cost can be reduced.

[0008] In an alternative embodiment, the thickness of the tab connection portion is T, where 0.6 mm ≤ T ≤ 2.5 mm.

[0009] In an alternative embodiment, the reinforcing rib is a groove provided on one surface of the tab connection portion, and along the recessed direction, the outer bottom surface of the groove is recessed from the outer surface of the tab connection portion.

[0010] In an alternative embodiment, the depth H by which the outer bottom surface of the groove is recessed from the outer surface of the tab connection portion satisfies 0.5T ≤ H ≤ 3T.

[0011] In an alternative embodiment, the width of the inner cavity of the groove is W, where 0.5T ≤ W ≤ 3T.

[0012] In an alternative embodiment, the tab includes a root portion connected to the electrode group and a bent portion connected to the root portion. The bent portion and the root portion are arranged at an angle. The bent portion is provided on the surface of the tab connection partition and is welded to the tab connection partition.

[0013] In an alternative embodiment, the length of the reinforcing rib is L, and the length of the tab is L1, where L > L1.

[0014] In an alternative embodiment, along the thickness direction of the connecting piece, the cross-section of the groove is rectangular.

[0015] In an alternative embodiment, along the length direction of the connecting piece, the reinforcing rib extends from one side of the tab connection portion towards the tab connection portion.

[0016] In a second aspect, the present invention further provides a battery pack, including a plurality of battery cells according to any one of the above technical solutions.

[0017] Beneficial effects: Since the battery pack includes battery cells, it has the same effects as the battery cells, which will not be elaborated here. Description of the Drawings

[0018] In order to more clearly illustrate the specific embodiments of the present invention 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 invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 It is a schematic structural diagram of a connecting piece in a battery cell according to an embodiment of the present invention;

[0020] Figure 2 For Figure 1 the top view of the connecting piece shown;

[0021] Figure 3 is a cross-sectional view taken along line A-A in Figure 2 ;

[0022] Figure 4 is a cross-sectional view taken along line B-B in Figure 2 ;

[0023] Figure 5 is a schematic structural view of the connecting piece and the electrode group in the first assembly state shown in Figure 1 ;

[0024] Figure 6 is a schematic structural view of the connecting piece and the electrode group in the second assembly state shown in Figure 1 ;

[0025] Figure 7 is a top view of Figure 6 ;

[0026] Figure 8 is a cross-sectional view taken along line C-C in Figure 7 ;

[0027] Figure 9 is an enlarged view of the local structure in Figure 8 ;

[0028] Figure 10 is a schematic structural view of a battery cell of an embodiment of the present utility model in a certain assembly state;

[0029] Figure 11 is a schematic structural view of the battery cell shown in Figure 10 in another assembly state;

[0030] Figure 12 is a top view of Figure 11 ;

[0031] Figure 13 is a cross-sectional view taken along line D-D in Figure 12 ;

[0032] Figure 14 is an enlarged view of the local structure in Figure 13 ;

[0033] Explanation of reference numerals:

[0034] 1. Cover plate; 11. Welding through-hole; 2. Electrode group; 21. Tab; 211. Root; 212. Bending part; 3. Connecting piece; 31. Terminal connection part; 32. Tab connection part; 321. Tab connection partition; 33. Reinforcing rib; 4. Terminal; 5. Sealing plate; 6. Upper plastic; 7. Sealing ring; 8. Lower plastic; 9. Explosion-proof valve; 10. Housing; 20. Liquid injection hole. Detailed implementation manners

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below 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 skilled 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.

[0036] The following will describe the embodiments of the present utility model in conjunction with Figures 1 to 14 , to describe the embodiments of the present utility model.

[0037] According to an embodiment of the present utility model, on the one hand, a battery cell is provided, which includes a cover plate 1, an electrode group 2, and a connecting piece 3. The cover plate 1 is provided with a pole column 4 and a welding through hole 11; the electrode group 2 is arranged inside the cover plate 1, and two electrode tabs 21 are provided corresponding to each pole column 4 on one side of the electrode group 2 close to the pole column 4; the connecting piece 3 is arranged between the cover plate 1 and the electrode group 2, and the connecting piece 3 includes a pole column connecting portion 31, an electrode tab connecting portion 32, and a reinforcing rib 33. The pole column connecting portion 31 is welded to the pole column 4, and the electrode tab connecting portion 32 is welded to the electrode tab 21 through the welding through hole 11. Along the thickness direction of the electrode tab connecting portion 32, the reinforcing rib 33 is arranged on any surface of the electrode tab connecting portion 32, and at least one of the inner surface and the outer surface of the reinforcing rib 33 is not coplanar with the electrode tab connecting portion 32; the reinforcing rib 33 extends along the length direction of the electrode tab connecting portion 32, dividing the electrode tab connecting portion 32 into two electrode tab connecting zones 321, and the two electrode tab connecting zones 321 are respectively used to connect one electrode tab 21.

[0038] In the battery cell provided by the embodiment of the present utility model, the connecting piece 3 is provided with the reinforcing rib 33 at the electrode tab connecting portion 32. Since at least one of the inner surface and the outer surface of the reinforcing rib 33 is not coplanar with the electrode tab connecting portion 32, the reinforcing rib 33 can play a role in strengthening the structure of the connecting piece 3 itself. With the connecting piece 3 having such a structure, when welding the connecting piece 3 and the electrode tab 21, there is no need to set up an auxiliary tooling for support, and only relying on the structural strength of the connecting piece 3 itself can ensure zero-gap contact between the connecting piece 3 and the electrode tab 21, ensuring the welding effect, saving space, and improving the space utilization rate in the height direction of the battery cell. At the same time, the cover plate 1 is provided with one welding through hole 11, and the connecting piece 3 and the electrode tab 21 are welded through the welding through hole 11. Since the cover plate 1 is only provided with one welding through hole 11, the continuity of welding can be ensured, one welding process can be reduced, and the cost can be reduced.

[0039] Specifically, the inner surface or the outer surface of the structural member in this article refers to that, in the state of the battery cell, the surface facing the electrode group inside the battery cell is the inner surface, and the surface away from the electrode group inside the battery cell is the outer surface.

[0040] Specifically, the connecting piece 3 and the tab 21 are fixed by welding processes such as laser welding or ultrasonic welding.

[0041] Specifically, along the thickness direction of the tab connecting portion 32, the tab connecting portion 32 has two surfaces, and the reinforcing rib 33 can be provided on any one of the surfaces of the tab connecting portion 32. Of course, the reinforcing rib 33 can also be provided on both surfaces. In addition, among the inner surface and the outer surface of the reinforcing rib 33, at least one of them is not coplanar with the tab connecting portion 32, that is, at least one surface of the reinforcing rib 33 is recessed from the surface of the tab connecting portion 32, or at least one surface of the reinforcing rib 33 protrudes from the surface of the tab connecting portion 32. The reinforcing rib 33 includes protrusions and / or grooves, and the orientation of the protrusions or grooves is not limited.

[0042] In Figure 13 the orientation shown, the cover plate 1 of the battery cell is on the top, the electrode assembly 2 is on the bottom, and the connecting piece 3 is located between the cover plate 1 and the electrode assembly 2. In this embodiment, the reinforcing rib 33 is a protrusion provided on the upper surface of the tab connecting portion 32 and facing away from the electrode assembly 2. At the same time, on the lower surface of the tab connecting portion 32, the reinforcing rib 33 forms a groove.

[0043] In an alternative embodiment, the reinforcing rib 33 is a protrusion facing the side close to the electrode assembly 2.

[0044] In some embodiments, the thickness of the tab connecting portion 32 is T, and 0.6 mm ≤ T ≤ 2.5 mm.

[0045] By controlling the thickness T of the tab connecting portion 32 within the range of 0.6 mm to 2.5 mm, the strength of the tab connecting portion 32 can be ensured, the deformation of the tab connecting portion 32 due to welding heat can be avoided, and the welding effect between the tab 21 and the connecting piece 3 can be ensured; at the same time, the thickness of the connecting piece 3 can be controlled within a reasonable range, the space occupied in the height direction of the battery cell can be reduced, and the space utilization rate can be improved.

[0046] In some embodiments, the reinforcing rib 33 is a groove provided on one surface of the tab connecting portion 32, and along the recessed direction, the outer bottom surface of the groove is recessed from the outer surface of the tab connecting portion 32.

[0047] Specifically, the outer bottom surface of the groove refers to the surface of the groove bottom away from its inner cavity.

[0048] The connecting piece 3 with such a structure can be integrally formed by stamping, reducing the processing difficulty.

[0049] Further, in this embodiment, the inner bottom surface of the groove is recessed from the other surface of the tab connecting portion 32. Here, the "one surface" and the "other surface" of the tab connecting portion 32 are two opposite surfaces.

[0050] In some embodiments, the depth H of the outer bottom surface of the groove recessed from the outer surface of the tab connection portion 32 satisfies 0.5T ≤ H ≤ 3T.

[0051] By controlling the depth H of the outer bottom surface of the groove recessed from the outer surface of the tab connection portion 32 within the range of 0.5T to 3T, the manufacturability and strength of the reinforcing rib 33 can be ensured.

[0052] In some embodiments, the width of the inner cavity of the groove is W, and 0.5T ≤ W ≤ 3T.

[0053] By setting the width W of the inner cavity of the groove within the range of 0.5T to 3T, the manufacturability and strength of the reinforcing rib 33 can be ensured.

[0054] In some embodiments, the tab 21 includes a root portion 211 connected to the electrode group 2 and a bent portion 212 connected to the root portion 211. The bent portion 212 and the root portion 211 are arranged at an angle. The bent portion 212 is disposed on the surface of the tab connection partition 321 and is welded to the tab connection partition 321.

[0055] Specifically, two tabs 21 of one polarity are located on both sides of the tab connection portion 32 of the connection piece 3. The tabs 21 are bent by 90°. The bent portions 212 of each tab 21 are respectively pressed on the surfaces of the corresponding tab connection partitions 321 on both sides, and then the bent portions 212 and the tab connection partitions 321 are welded and fixed through a welding process.

[0056] In some embodiments, the length of the reinforcing rib 33 is L, and the length of the tab 21 is L1, where L > L1.

[0057] Since the length L of the reinforcing rib 33 is greater than the length L1 of the tab 21, it can be ensured that when the connection piece 3 and the tab 21 are welded, relying on the structural strength of the connection piece 3 itself, there is zero-gap contact between the tab connection partition 321 of the connection piece 3 and the tab 21, ensuring the welding effect.

[0058] In some embodiments, along the thickness direction of the connection piece 3, the cross-section of the groove is rectangular.

[0059] Setting the structure of the groove as rectangular is convenient for processing.

[0060] In some embodiments, along the length direction of the connection piece 3, the reinforcing rib 33 extends from one side of the tab connection portion 32 to the terminal connection portion 31.

[0061] The reinforcing rib 33 extends from one side of the tab connection portion 32 to the terminal connection portion 31, which is convenient for the processing of the reinforcing rib 33.

[0062] In some embodiments, the battery cell further includes a housing 10, the housing 10 has a receiving cavity, the housing 10 has an open end, the electrode assembly 2 is disposed inside the housing 10, and a cover plate 1 is disposed at the open end of the housing 10 to encapsulate the electrode assembly 2 inside the housing 10.

[0063] In some embodiments, the battery cell further includes an upper plastic 6, a sealing ring 7 and a lower plastic 8.

[0064] The upper plastic 6 is disposed between the outer surfaces of the pole post 4 and the cover plate 1 away from the electrode assembly 2 to insulatively connect the pole post 4 and the cover plate 1.

[0065] The cover plate 1 is provided with a mounting hole, the pole post 4 is disposed in the mounting hole, and the sealing ring 7 is disposed between the outer cylindrical surface of the pole post 4 and the inner wall of the mounting hole to sealingly connect the pole post 4 and the cover plate 1.

[0066] The lower plastic 8 is disposed between the inner surfaces of the connecting piece 3 and the cover plate 1 close to the electrode assembly 2 to insulatively connect the connecting piece 3 and the cover plate 1.

[0067] A sealing plate 5 is disposed on the welding through hole 11 of the cover plate 1 to seal the welding through hole 11. An explosion-proof valve 9 and a liquid injection hole 20 are provided on the sealing plate 5.

[0068] After structural components such as the cover plate 1, the pole post 4, the connecting piece 3, the upper plastic 6, the sealing ring 7, the lower plastic 8, and the explosion-proof valve 9 are assembled, they form a battery cell cover plate assembly and are supplied in the form of an assembly, which is beneficial to improving the production efficiency of the battery cell.

[0069] According to an embodiment of the present invention, on the other hand, a battery pack is further provided, which includes a plurality of battery cells according to any one of the above technical solutions.

[0070] Since the battery pack includes the battery cell in the above embodiment and has the same effects as the battery cell, they will not be elaborated here.

[0071] Although the embodiments of the present invention are described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A battery cell, characterized in that: include: A cover plate, wherein the cover plate is provided with a pole and a welding through hole; A pole group, the pole group is arranged on the inner side of the cover plate, and two pole ears are arranged on one side of the pole group close to the pole corresponding to each pole; A connecting piece, the connecting piece is arranged between the cover plate and the pole group, the connecting piece includes a pole column connecting part, a pole lug connecting part and a reinforcing rib, the pole column connecting part is welded to the pole column, the pole lug connecting part and the pole lug are welded through the welding through hole, along the thickness direction of the pole lug connecting part, the reinforcing rib is arranged on any surface of the pole lug connecting part, and at least one of the outer surface and the inner surface of the reinforcing rib is not coplanar with the pole lug connecting part; The reinforcing rib extends along the length direction of the tab connection portion, dividing the tab connection portion into two tab connection partitions, and the two tab connection partitions are respectively used to connect one tab.

2. The battery cell according to claim 1, characterized in that: The thickness of the tab connection portion is T, 0.6 mm ≤ T ≤ 2.5 mm.

3. The battery cell according to claim 2, characterized in that: The reinforcing rib is a groove provided on one surface of the pole tab connecting portion, and along the recessed direction, the outer bottom surface of the groove is recessed in the outer surface of the pole tab connecting portion.

4. The battery cell according to claim 3, characterized in that: The outer bottom surface of the groove is sunken into the outer surface of the tab connecting portion to a depth of H, and 0.5T≤H≤3T.

5. The battery cell according to claim 3 or 4, characterized in that: The width of the inner cavity of the groove is W, and 0.5T≤W≤3T.

6. The battery cell according to any one of claims 1 to 4, characterized in that: The pole lug includes a root portion connected to the pole group and a bent portion connected to the root, the bent portion and the root are arranged at an angle, the bent portion is arranged on the surface of the pole lug connection partition, and is welded to the pole lug connection partition.

7. The battery cell according to any one of claims 1 to 4, characterized in that: The length of the reinforcing rib is L, the length of the pole ear is L1, and L>L1.

8. The battery cell according to claim 3 or 4, characterized in that: Along the thickness direction of the connecting sheet, the cross section of the groove is rectangular.

9. The battery cell according to any one of claims 1 to 4, characterized in that: Along the length direction of the connecting piece, the reinforcing rib extends from one side of the pole lug connecting portion to the pole column connecting portion.

10. A battery pack, characterized in that: The invention comprises a plurality of battery cells according to any one of claims 1 to 9.

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