CN220368102U

CN220368102U - Battery cell connection structure and battery cell

Info

Publication number: CN220368102U
Application number: CN202321473059.3U
Authority: CN
Inventors: 孙海明; 叶云清; 罗懿; 李季
Original assignee: Cornex New Energy Co ltd
Current assignee: Cornex New Energy Co ltd
Priority date: 2023-06-08
Filing date: 2023-06-08
Publication date: 2024-01-19
Anticipated expiration: 2033-06-08

Abstract

The utility model provides a battery core connecting structure and a battery core, and belongs to the technical field of new energy batteries. The battery cell connecting structure comprises a battery cell group and a welding protection sheet. The battery cell group comprises a plurality of single battery cells, the end parts of the single battery cells are provided with electrode lugs, the electrode lugs of the single battery cells are arranged in a stacked mode and welded and fixed, and the welding protection sheet is fixedly connected to one side face of the electrode lugs in the stacking direction and covers the end parts of the electrode lugs. By adopting the battery cell connecting structure and the battery cell provided by the embodiment of the utility model, the problem of reverse insertion of the battery cell tab in the parallel welding and bending processes of the battery cell tab in the related technology can be solved, and the product yield is improved.

Description

Battery cell connection structure and battery cell

Technical Field

The utility model relates to the technical field of new energy batteries, in particular to a battery cell connecting structure and a battery cell.

Background

In the field of power batteries, the anxiety of the current endurance mileage is always present, batteries which are pursued to have higher energy density and high safety are always pursued in industry, and as the energy density of a ternary material system is increased, the safety risk is also increased, so that in recent years, the direction of lithium batteries is inclined towards lithium iron phosphate, but the energy density of the lithium iron phosphate is close to a theoretical value, and further increase is very difficult to be wanted.

In the related art, in order to improve the cruising ability, a dual-cell battery is generally used to improve the power supply cruising of the power terminal. The double-cell battery adopts a mode of connecting two cell bodies in parallel so as to improve the overall capacitance of the power battery. The main mode of connection between the lugs and the poles of the two battery core bodies inside the shell is through the connection of the switching sheet, and after the homopolar lugs of the two battery cores are connected with the switching sheet through ultrasonic welding, the switching sheet is welded with the corresponding pole of the power battery through the laser welding mode.

By adopting the connection mode in the related art, the two battery core bodies are in a horizontal state in the process of welding the electrode lugs, and after welding, the two battery core bodies are required to be oppositely folded by 90 degrees and are attached to form an upright state for being placed in the shell. Because the two lugs are welded after lamination, the length of the lugs is deviated in the process of folding, and the ends of the lugs in the welding area can be tilted and reversely inserted into the end face of the battery core body to form micro short circuit due to stress when the lugs are bent.

Disclosure of Invention

The embodiment of the utility model provides a battery cell connecting structure and a battery cell, which can solve the problem of reverse insertion of the battery cell tab in the parallel welding and bending processes of the battery cell tab in the related technology and improve the product yield. The technical scheme is as follows:

in a first aspect, an embodiment of the present utility model provides a connection structure for a battery cell, including: the battery cell group and the welding protection sheet,

the battery cell group comprises a plurality of single battery cells, the end parts of the single battery cells are provided with lugs, a plurality of the lugs of the single battery cells are arranged in a stacked mode and welded and fixed, and the welding protection sheet is fixedly connected to one side face of the lugs in the stacking direction and covers the end parts of the lugs.

Optionally, a first folded edge is arranged on one side edge, close to the end part of the tab, of the welding protection sheet, and the first folded edge is bent towards the tab.

Optionally, a second folded edge is arranged on one side edge, far away from the end part of the tab, of the welding protection sheet, and the second folded edge is bent back to the tab.

Optionally, the bending positions of the first folding edge and the second folding edge are provided with arc chamfers.

Optionally, a plurality of arc protrusions are convexly arranged on one side surface, facing the tab, of the welding protection sheet, and the arc protrusions are uniformly arranged at intervals.

Optionally, the diameter of the circular arc protrusion ranges from 0.2mm to 0.5mm.

Optionally, the battery cell group includes two single battery cells, and the tabs of the two single battery cells are oppositely stacked and welded and fixed.

Optionally, the thickness of the welding protection sheet ranges from 0.3mm to 0.8mm.

Optionally, the welding protection sheet is an aluminum alloy sheet or a copper sheet.

In a second aspect, an embodiment of the present utility model provides a battery cell, including the battery cell connection structure of the first aspect, and further including a top cover assembly, where a pole is disposed on the top cover assembly, and another side surface of the plurality of pole lugs in the stacking direction is fixedly connected with the pole.

The technical scheme provided by the embodiment of the utility model has the beneficial effects that at least:

in the preparation process, the lugs of the plurality of single battery cells are stacked oppositely and fixed by ultrasonic welding. And then arranging the welding protection sheets on the stacked tabs, wherein the widths of the welding protection sheets are consistent with those of the tabs, and the lengths of the welding protection sheets are slightly longer than the lengths of overlapping sections of the tabs which are arranged in a stacking manner. One end of the welding protection sheet slightly protrudes out of the end part of the tab attached to the welding protection sheet to cover the tab, and finally the welding protection sheet is fixed with the tab through welding. In the subsequent preparation process of the cell connection structure, in order to be placed in the square cell shell, the plurality of single cells in the cell group need to be turned over by 90 degrees in opposite directions so as to be adhered to each other through a large surface, thereby being matched with the inner cavity of the cell shell. The tab fixed by pre-welding is folded by 90 degrees along with the single battery cell except for the laminated part. At the moment, the end faces of the lugs close to the single battery cells are provided with welding protection sheets in a welding mode, and the welding protection sheets can cover and shield the end parts of the lugs close to one side of the single battery cells, so that short circuits caused by tilting of the lug ends and end face contact of the single battery cells are avoided. The problem of the tab of carrying out electric core tab parallel welding and buckling in-process in the related art is solved, and the product yield is improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a structural exploded view of a cell connection structure according to an embodiment of the present utility model;

fig. 2 is a schematic structural view of one side of a welding protection sheet according to an embodiment of the present utility model;

FIG. 3 is a schematic view of another side of a welding protection sheet according to an embodiment of the present utility model;

fig. 4 is a schematic diagram of a connection structure between a battery cell connection structure and a top cover assembly according to an embodiment of the present utility model;

FIG. 5 is a schematic side view of a battery cell connection structure and a top cover assembly according to an embodiment of the present utility model;

fig. 6 is a side view of the internal structure of a battery cell according to an embodiment of the present utility model.

In the figure:

1-a battery cell group; 2-welding a protective sheet; 3-a top cover assembly; 11-monomer battery cells; 21-first flanging; 22-second flanging; 23-arc protrusions; 31-pole; 111-electrode lugs; 111 a-positive tab; 111 b-negative electrode ear.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present utility model more apparent, the embodiments of the present utility model will be described in further detail with reference to the accompanying drawings.

By adopting the connection mode in the related art, the two battery core bodies are in a horizontal state in the process of welding the electrode lugs, and after welding, the two battery core bodies are required to be oppositely folded by 90 degrees and are attached to form an upright state for being placed in the shell. Because two tabs are welded structures after lamination, the length of the tabs is deviated in the process of folding, the ends of the tabs in the welding area can be tilted and reversely inserted into the end face of the battery core body to form micro short circuit due to stress when the tabs are bent, and the root of the tab is easy to bulge or fold due to folding in the deformation process, so that the tab is easy to break.

Fig. 1 is a structural exploded view of a cell connection structure according to an embodiment of the present utility model. Fig. 2 is a schematic structural view of one side of a welding protection sheet according to an embodiment of the present utility model. Fig. 3 is a schematic structural view of the other side of the welding protection sheet according to the embodiment of the present utility model. Fig. 4 is a schematic diagram of a connection structure between a battery cell connection structure and a top cover assembly according to an embodiment of the present utility model. Fig. 5 is a schematic side view of a battery cell connection structure and a top cover assembly according to an embodiment of the present utility model. As shown in fig. 1 to 5, through practice, an embodiment of the present utility model provides a cell connection structure including a cell group 1 and a welding protection sheet 2.

The battery cell group 1 comprises a plurality of single battery cells 11, wherein the end parts of the single battery cells 11 are provided with electrode lugs 111, the plurality of electrode lugs 111 of the single battery cells 11 are arranged in a stacked mode and welded and fixed, and the welding protection sheet 2 is fixedly connected to one side face of the electrode lugs 111 in the stacking direction and covers the end parts of the electrode lugs 111.

In the embodiment of the utility model, the battery cell group 1 comprises two single battery cells 11, and the top end surface of each single battery cell 11 is convexly provided with a rectangular sheet-shaped tab 111. Tab 111 includes positive tab 111a and negative tab 111b, which are arranged at intervals along the long-side direction of cell 11. In the preparation process, one side of the two single battery cells 11 provided with the tabs 111 is oppositely arranged, wherein the end parts of the positive tabs 111a of the two single battery cells 11 are oppositely stacked and fixed by ultrasonic welding, and the end parts of the negative tabs 111b of the two single battery cells 11 are oppositely stacked and fixed by ultrasonic welding. Then, the welding protection sheets 2 which are also rectangular are respectively arranged on the stacked positive electrode tab 111a and the stacked negative electrode tab 111b, the width of the welding protection sheets 2 is consistent with the width of the electrode tab 111, and the length of the welding protection sheets 2 is slightly longer than the length of the overlapped sections of the electrode tabs 111 which are arranged in a stacked manner. One end of the welding protection sheet 2 protrudes slightly beyond the end of the tab 111 attached thereto to cover, and is finally fixed to the tab 111 by welding. In the subsequent process of manufacturing the cell connection structure, in order to be placed in the square cell housing, the two individual cells 11 in the cell group 1 need to be turned over by 90 ° in opposite directions so as to be attached to each other through a large surface, thereby being matched with the inner cavity of the cell housing. The pre-welded tab 111, except for the laminated part, is folded over by 90 ° along with the single cell 11 on the side connected to the single cell 11. In the two tabs 111 which are stacked and welded at this time, the end faces of the tabs 111 far away from the two single battery cores 11 can be used as pre-connection ends to be connected with the poles on the battery core shell through the current collector switching sheet or directly connected with the poles; and the end faces of the electrode lugs 111 close to the two single battery cells 11 are provided with the welding protection sheets 2 due to welding, and the welding protection sheets 2 can cover and shield the end parts of the electrode lugs 111 close to one side of the single battery cells 11, so that the short circuit caused by the fact that the electrode lugs are tilted up to be in contact with the end faces of the single battery cells 11 is avoided. The problem of tab reverse insertion in the parallel welding and bending processes of the battery cell tabs in the related technology can be solved, and the product yield is improved.

Optionally, a first folded edge 21 is disposed on one side of the welding protection sheet 2 near the end of the tab 111, and the first folded edge 21 is folded towards the tab 111. Illustratively, in the embodiment of the present utility model, the first folded edge 111 is formed by folding a side edge of the welding protection sheet 2 near the end of the tab 111, that is, a side edge protruding from one end of the tab 111. On the basis of ensuring complete coverage of the end part of the tab 111, the first side 21 bent towards the lower tab 111 can also isolate and guide the end face of the end part of the upper tab 111 and the root bending section of the lower tab 111, which is close to the single cell 11, so as to avoid bulge or fold caused by contact between the end part of the upper tab 111 and the root bending section of the lower tab 111, which is close to the single cell 11, and eliminate the hidden danger of breakage of the side tab 111 after bending, thereby further improving the product yield.

Optionally, a second folded edge 22 is disposed on one side of the welding protection sheet 2 away from the end of the tab 111, and the second folded edge 22 is folded back to the tab 111. In the embodiment of the present utility model, the second flange 22 is formed on the other side edge of the welding protection sheet 2 away from the end of the tab 111, that is, the other side edge opposite to the first flange 21, and by providing the second flange 22, the root bending section of the tab 111 located at the lower layer and close to the single cell 11 after bending can be supported and guided, so as to avoid bulge or fold in the bending and welding process, eliminate the hidden danger of breaking the tab 111 after bending, and further improve the product yield.

Optionally, the bending positions of the first flange 21 and the second flange 22 are provided with arc chamfers. Illustratively, in the embodiment of the present utility model, by providing the arc chamfer, the contact between the first flange 21 and the second flange 22 and the tab 111 is smoother, so as to avoid the bulge or fold of the tab 111 caused by scratch, and further improve the product yield.

Alternatively, the welding protection plate 2 is convexly provided with a plurality of circular arc protrusions 23 on a side surface facing the tab 111, and the plurality of circular arc protrusions 23 are uniformly arranged at intervals. Illustratively, in the embodiment of the present utility model, when the welding protection sheet 2 is connected to the tab 111 provided in a laminated manner, a plurality of circular arc protrusions 23 are uniformly arranged at intervals on one side surface thereof for adhering to the tab 111. In the process of bonding and ultrasonic welding connection, the arc protrusions 23 can enable the lugs 111 arranged in a laminated mode to be fully pressed and tightly pressed, so that the phenomenon of cold joint between the lugs 111 in multiple layers is avoided, and the product yield is further improved.

Alternatively, in the embodiment of the present utility model, the diameter of the circular arc protrusion 23 ranges from 0.2mm to 0.5mm.

Alternatively, in the embodiment of the present utility model, the thickness of the welding protection sheet 2 ranges from 0.3mm to 0.8mm. The welding protection sheet 2 is an aluminum alloy sheet or a copper sheet.

Fig. 6 is a side view of the internal structure of a battery cell according to an embodiment of the present utility model. As shown in fig. 6, the embodiment of the utility model further provides a battery core, which comprises a battery core connecting structure as shown in fig. 1 to 5, and further comprises a top cover assembly 3, wherein a pole 31 is arranged on the top cover assembly 3, and the other side surfaces of the plurality of pole lugs 111 in the stacking direction are fixedly connected with the pole 31. In the embodiment of the utility model, after the electrode tabs 111 of the plurality of single battery cells 11 in the battery cell connecting structure are stacked and pre-welded and the welding protection sheets 2 are arranged, the other side surface in the stacking direction is directly welded and connected with the corresponding electrode posts 31 on the top cover assembly 3, so that the current collector connecting sheet for switching between the traditional electrode tabs and the electrode posts is removed, and the utilization rate of the internal space of the battery cells and the overcurrent capacity can be effectively improved.

Unless defined otherwise, technical or scientific terms used herein should be given the ordinary meaning as understood by one of ordinary skill in the art to which this utility model belongs. The terms "first," "second," and the like in the description and in the claims, are not used for any order, quantity, or importance, but are used for distinguishing between different elements. Likewise, the terms "a" or "an" and the like do not denote a limitation of quantity, but rather denote the presence of at least one. The word "comprising" or "comprises", and the like, is intended to mean that elements or items that are present in front of "comprising" or "comprising" are included in the word "comprising" or "comprising", and equivalents thereof, without excluding other elements or items. The terms "connected" or "connected," and the like, are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", etc. are used merely to denote relative positional relationships, which may also change accordingly when the absolute position of the object to be described changes.

The foregoing description of the preferred embodiments of the present utility model is not intended to limit the utility model, but rather, the utility model is to be construed as limited to the appended claims.

Claims

1. A cell connection structure, comprising: a battery cell group (1) and a welding protection sheet (2),

the battery cell group (1) comprises a plurality of single battery cells (11), the end parts of the single battery cells (11) are provided with electrode lugs (111), a plurality of electrode lugs (111) of the single battery cells (11) are arranged in a stacked mode and welded and fixed, and the welding protection sheet (2) is fixedly connected to one side face of the electrode lugs (111) in the stacking direction and covers the end parts of the electrode lugs (111).

2. The cell connection structure according to claim 1, wherein a side edge of the welding protection sheet (2) near the end of the tab (111) is provided with a first folded edge (21), and the first folded edge (21) is folded toward the tab (111).

3. The cell connection structure according to claim 2, wherein a second folded edge (22) is provided on a side edge of the welding protection sheet (2) away from the end of the tab (111), and the second folded edge (22) is folded back to the tab (111).

4. A cell connection according to claim 3, characterized in that the bending positions of the first and second folds (21, 22) are provided with circular arc chamfers.

5. The cell connection structure according to claim 1, wherein a plurality of circular arc protrusions (23) are convexly arranged on a side surface of the welding protection sheet (2) facing the tab (111), and the plurality of circular arc protrusions (23) are uniformly arranged at intervals.

6. The cell connection structure according to claim 5, wherein the diameter of the circular arc protrusion (23) ranges from 0.2mm to 0.5mm.

7. The cell connection structure according to any one of claims 1 to 6, wherein the cell group (1) includes two unit cells (11), and the tabs (111) of the two unit cells (11) are arranged in opposition to each other in a stacked manner and welded.

8. The cell connection structure according to any one of claims 1 to 6, wherein the thickness of the welding protection sheet (2) ranges from 0.3mm to 0.8mm.

9. The cell connection structure according to any one of claims 1 to 6, wherein the welding protection sheet (2) is an aluminum alloy sheet or a copper sheet.

10. A battery cell comprising the battery cell connecting structure according to any one of claims 1 to 9, further comprising a top cover assembly (3), wherein a pole (31) is provided on the top cover assembly (3), and the other side surfaces of the plurality of pole lugs (111) in the stacking direction are fixedly connected with the pole (31).