All-tab cylindrical lithium battery negative electrode confluence plate and lithium battery

Abstract

The embodiment of the utility model provides an all-tab cylindrical lithium battery negative electrode confluence plate and a lithium battery, and belongs to the technical field of lithium batteries. The negative collector plate comprises: a plate body; the first welding area is arranged in the center of the disc body; the second welding area is arranged on the disc body and is far away from the center, a welding mark of the second welding area comprises a plurality of first round points, and the first round points form a circular ring concentric with the disc body. The first welding full area and the second welding area are arranged, so that the pole piece freely expands, the possibility of breakage of the pole piece is reduced, and various properties of the lithium battery are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium batteries, and in particular to a full-ear cylindrical lithium battery negative electrode busbar and a lithium battery. Background Art

[0002] The rapid development of the power tool industry and the complex application scenarios currently facing power tools pose significant challenges to the performance of traditional lithium-ion batteries. Conventional lithium-ion batteries use a single-pole design for the positive electrode. Under continuous high-current discharge conditions, they experience rapid temperature rise and insufficient transient high-current performance, making them unsuitable for some high-power power tools.

[0003] The use of full-tab cylindrical lithium-ion batteries can greatly improve the above-mentioned problems. However, the busbar welding method currently used in full-tab cylindrical lithium-ion batteries is to weld the flattened electrode group to the busbar in all directions. As a result, the positive and negative electrodes have no space to expand during the charge and discharge process and are subjected to huge compression, which easily leads to the risk of electrode breakage, thereby affecting the electrical and safety performance of the battery. Utility Model Content

[0004] The utility model provides a full-pole-ear cylindrical lithium battery negative electrode busbar and a lithium battery, which solves the problem that positive and negative electrode sheets are easily broken during the charging and discharging process.

[0005] In order to achieve the above-mentioned object, the present invention provides a negative electrode busbar for a cylindrical lithium battery with full tabs, the negative electrode busbar comprising:

[0006] disc body;

[0007] A first welding area is provided at the center of the disc;

[0008] The second welding area is arranged on the disk body and away from the center. The welding mark of the second welding area includes a plurality of first dots, and the plurality of first dots form a circular ring concentric with the disk body.

[0009] Optionally, the weld mark shape of the first welding area includes a plurality of second dots, and the second dots are convex upward.

[0010] Optionally, the distance from the center of the first circle to the center of the disk is 50%-90% of the radius of the disk.

[0011] Optionally, the first welding area is provided with a first opening, the edge of the disk body is provided with a second opening, and the first opening is semicircular in shape.

[0012] Optionally, the number of the second openings is 4, and the interval between two adjacent second openings is 90°.

[0013] On the other hand, the present invention also provides a full-tab cylindrical lithium battery, the lithium battery comprising:

[0014] Battery electrode group;

[0015] A positive busbar connected to one end of the battery electrode group for collecting current;

[0016] A negative busbar is connected to the other end of the battery electrode group and is used to collect current. The negative busbar includes:

[0017] disc body;

[0018] A first welding area is provided at the center of the disc;

[0019] The second welding area is arranged on the disk body and away from the center. The welding mark of the second welding area includes a plurality of first dots, and the plurality of first dots form a circular ring concentric with the disk body.

[0020] Optionally, the weld mark shape of the first welding area includes a plurality of second dots, and the second dots are convex upward.

[0021] Optionally, the distance from the center of the first circle to the center of the disk is 50%-90% of the radius of the disk.

[0022] Optionally, the first welding area is provided with a first opening, the edge of the disk body is provided with a second opening, and the first opening is semicircular in shape.

[0023] Optionally, the number of the second openings is 4, and the interval between two adjacent second openings is 90°.

[0024] Through the above-mentioned technical solution, the present invention provides a negative electrode busbar for a cylindrical lithium battery with full tabs and a lithium battery. By disposing a first welding area at the center of the disc and a second welding area away from the center, the electrode sheets have space to expand during the charging and discharging process. The weld marks of the second welding area include multiple first circles, with the distance from the center of the first circle to the center of the disc being 50%-90% of the disc radius. This ensures welding strength, avoiding cold welds or insufficient welding strength, while also preventing overly tight welding that could cause electrode sheet breakage during charging and discharging. Compared with the prior art, the present invention has a simple structure, improves welding quality and efficiency, and ensures the electrical and safety performance of the battery.

[0025] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following detailed description, they are used to explain the embodiments of the present invention, but do not constitute a limitation of the embodiments of the present invention. In the accompanying drawings:

[0027] Figure 1 Schematic diagram of a negative busbar according to one embodiment of the present invention.

[0028] Description of Reference Numerals

[0029] 1. Plate 2. First welding area

[0030] 3. Second welding area 4. First opening

[0031] 5. Second opening DETAILED DESCRIPTION

[0032] The following describes the specific implementation of the embodiment of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the embodiment of the present invention and is not intended to limit the embodiment of the present invention.

[0033] In the embodiments of the present invention, unless otherwise specified, directional words such as "up, down, top, bottom" are usually used to describe the relative positions of components in the directions shown in the drawings or in the vertical, perpendicular or gravity directions.

[0034] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features specified as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0035] Figure 1This figure is a schematic diagram of a negative busbar according to one embodiment of the present invention. The figure shows the negative busbar, which includes a body 1, a first welding area 2, and a second welding area 3. The first welding area 2 is located at the center of the body 1, while the second welding area 3 is located on the body 1, further away from the center. The weld marks of the second welding area 3 include multiple first circular dots, which form a circular ring concentric with the body 1. By providing the first and second welding areas 2 and 3 on the body 1, the electrode sheets can expand freely, reducing the possibility of fracture and improving various battery performances.

[0036] In this embodiment, the weld shape of the first weld region 2 can be any of various shapes known to those skilled in the art. In one example of the present invention, the weld mark of the first weld region 2 includes a plurality of second dots. These second dots are upwardly protruding, which helps prevent weak welds and improves weld quality.

[0037] In this embodiment, the dimensions of the second welding region 3 can be various sizes known to those skilled in the art. In one example of the present invention, the distance from the center of the first circle to the center of the disk body 1 is 50%-90% of the radius of the disk body 1. Specifically, when the distance from the center of the first circle to the center of the disk body 1 is 50% of the radius of the disk body 1, the welding force is 85 N, the internal resistance is 3.7 mΩ, and the battery undergoes 600 cycles of charge and discharge testing at 6 A and 30 A, with the battery performance retaining 87% of the original performance. Ten tested batteries were disassembled and found to be intact with no fractures in the electrode sheets. When the distance from the center of the first circle to the center of the disk body 1 is 70% of the radius of the disk body 1, the welding force is 91 N, the internal resistance is 3.6 mΩ, and the battery undergoes 600 cycles of charge and discharge testing at 6 A and 30 A, with the battery performance retaining 87% of the original performance. Ten tested batteries were disassembled and found to be intact with no fractures in the electrode sheets. When the distance from the center of the first point to the center of the disk 1 was 90% of the radius of the disk 1, the welding force was 95N and the internal resistance was 3.5mΩ. The battery was tested for 600 cycles at 6A charge and 30A discharge, and the battery performance remained 88% of the original performance. Disassembly of the ten tested batteries revealed that the electrodes were intact and without any cracks. When the distance from the center of the first point to the center of the disk 1 was 30% of the radius of the disk 1, the welding force was 72N and the internal resistance was 4.3mΩ. The battery was tested for 600 cycles at 6A charge and 30A discharge, and the battery performance remained 83% of the original performance, resulting in a failed test result. Under the conditions that the distance from the center of the first point to the center of the disk body 1 is 30% of the radius of the disk body 1 and the distance from the center of the first point to the center of the disk body 1 is 70% of the radius of the disk body 1, the welding tension is 105N, the internal resistance is 3.3mΩ, and the battery is subjected to 600 cycle charge and discharge tests under the conditions of 6A charging and 30A discharging. After the ten tested batteries were disassembled, it was found that the battery electrodes of three were broken, and the test results failed.

[0038] Test results show that a larger weld area results in a greater weld force, a lower internal resistance, and improved cycle performance. In normal production, when the battery's performance parameters are a weld force greater than 80N and an internal resistance less than 4.5mΩ, the battery undergoes 500 cycles of charge and discharge testing at 6A and 30A, maintaining over 85% of its original performance and ensuring no electrode breakage. The battery is deemed qualified. The distance from the center of the first circle to the center of the disc 1 is 50%-90% of the radius of the disc 1. This ensures weld strength, preventing cold welds or insufficient weld strength, while also preventing overly tight welds that could cause electrode breakage during charge and discharge.

[0039] In this embodiment, to improve liquid absorption efficiency, the disc body 1 is provided with openings. The locations of these openings can be various locations known to those skilled in the art. In one example of the present invention, specifically, the first welding region 2 is provided with a first opening 4, and the edge of the disc body 1 is provided with a second opening 5. The first opening 4 is semicircular in shape. The first opening 4 and the second opening 5 create a gap between the disc body 1 and the electrode assembly, which improves liquid absorption efficiency, reduces absorption time, and enhances efficiency when the electrolyte is injected.

[0040] In this embodiment, the number of the second openings 5 ​​can be a number known to those skilled in the art. In one example of the present invention, the number of the second openings 5 ​​is 4, and the interval between two adjacent second openings 5 ​​is 90°.

[0041] On the other hand, the present invention provides a full-pole lug cylindrical lithium battery, which includes a battery electrode group, a positive electrode busbar and a negative electrode busbar. The positive electrode busbar is connected to one end of the battery electrode group for collecting current, and the negative electrode busbar is connected to the other end of the battery electrode group for collecting current. Furthermore, the negative electrode busbar includes a disk body 1, a first welding area 2 and a second welding area 3. The first welding area 2 is arranged at the center of the disk body 1, and the second welding area 3 is arranged on the disk body 1 and away from the center. The weld mark of the second welding area 3 includes multiple first dots, and the multiple first dots form a circular ring concentric with the disk body 1. By arranging the first welding area 2 and the second welding area 3 on the disk body 1, the pole piece can be expanded freely, reducing the possibility of its breakage, and improving the various performances of the battery. In one example of the present invention, the preparation method of the full-pole lug cylindrical lithium battery includes preparing the positive electrode sheet, preparing the negative electrode sheet and assembling the battery. Among them, the preparation of positive electrode sheets includes first adding the positive electrode main material (ternary material), positive electrode auxiliary materials (conductive agent, binder), solvent, etc. into a slurry pot in order, stirring and kneading at high speed, stirring for 120-130 minutes, adding solvent and continuing to stir until the appropriate viscosity is reached, so as to obtain a positive electrode slurry that meets the requirements, and finally evenly coating the above slurry on the front and back sides of aluminum foil, and baking and rolling to obtain a positive electrode sheet that meets the requirements. The preparation of negative electrode sheets includes first adding the negative electrode main material (carbon material), negative electrode auxiliary materials (conductive agent, binder), solvent, etc. into a slurry pot in order, stirring and kneading at high speed, stirring for 100-110 minutes, adding solvent and continuing to stir until the appropriate viscosity is reached, so as to obtain a negative electrode slurry that meets the requirements, and finally evenly coating the above slurry on the front and back sides of copper foil, and baking and rolling to obtain a negative electrode sheet that meets the requirements. When assembling the battery, the positive and negative electrodes and the separator are first wound, and then the shell is installed, flattened, liquid is injected, the busbar is welded, and the sealing process is carried out. Finally, a full-ear cylindrical lithium battery is produced.

[0042] In this embodiment, the weld shape of the first weld region 2 can be any of various shapes known to those skilled in the art. In one example of the present invention, the weld mark of the first weld region 2 includes a plurality of second dots. These second dots are upwardly protruding, which helps prevent weak welds and improves weld quality.

[0043] In this embodiment, the dimensions of the second welding region 3 can be various sizes known to those skilled in the art. In one example of the present invention, the distance from the center of the first circle to the center of the disk body 1 is 50%-90% of the radius of the disk body 1. Specifically, when the distance from the center of the first circle to the center of the disk body 1 is 50% of the radius of the disk body 1, the welding force is 85 N, the internal resistance is 3.7 mΩ, and the battery undergoes 600 cycles of charge and discharge testing at 6 A and 30 A, with the battery performance retaining 87% of the original performance. Ten tested batteries were disassembled and found to be intact with no fractures in the electrode sheets. When the distance from the center of the first circle to the center of the disk body 1 is 70% of the radius of the disk body 1, the welding force is 91 N, the internal resistance is 3.6 mΩ, and the battery undergoes 600 cycles of charge and discharge testing at 6 A and 30 A, with the battery performance retaining 87% of the original performance. Ten tested batteries were disassembled and found to be intact with no fractures in the electrode sheets. When the distance from the center of the first point to the center of the disk 1 was 90% of the radius of the disk 1, the welding force was 95N and the internal resistance was 3.5mΩ. The battery was tested for 600 cycles at 6A charge and 30A discharge, and the battery performance remained 88% of the original performance. Disassembly of the ten tested batteries revealed that the electrodes were intact and without any cracks. When the distance from the center of the first point to the center of the disk 1 was 30% of the radius of the disk 1, the welding force was 72N and the internal resistance was 4.3mΩ. The battery was tested for 600 cycles at 6A charge and 30A discharge, and the battery performance remained 83% of the original performance, resulting in a failed test result. Under the conditions that the distance from the center of the first point to the center of the disk body 1 is 30% of the radius of the disk body 1 and the distance from the center of the first point to the center of the disk body 1 is 70% of the radius of the disk body 1, the welding tension is 105N, the internal resistance is 3.3mΩ, and the battery is subjected to 600 cycle charge and discharge tests under the conditions of 6A charging and 30A discharging. After the ten tested batteries were disassembled, it was found that the battery electrodes of three were broken, and the test results failed.

[0044] Test results show that a larger weld area results in a greater weld force, a lower internal resistance, and improved cycle performance. In normal production, when the battery's performance parameters are a weld force greater than 80N and an internal resistance less than 4.5mΩ, the battery undergoes 500 cycles of charge and discharge testing at 6A and 30A, maintaining over 85% of its original performance and ensuring no electrode breakage. The battery is deemed qualified. The distance from the center of the first circle to the center of the disc 1 is 50%-90% of the radius of the disc 1. This ensures weld strength, preventing cold welds or insufficient weld strength, while also preventing overly tight welds that could cause electrode breakage during charge and discharge.

[0045] In this embodiment, to improve liquid absorption efficiency, the disc body 1 is provided with openings. The locations of these openings can be various locations known to those skilled in the art. In one example of the present invention, specifically, the first welding region 2 is provided with a first opening 4, and the edge of the disc body 1 is provided with a second opening 5. The first opening 4 is semicircular in shape. The first opening 4 and the second opening 5 create a gap between the disc body 1 and the electrode assembly, which improves liquid absorption efficiency, reduces absorption time, and enhances efficiency when the electrolyte is injected.

[0046] In this embodiment, the number of the second openings 5 ​​can be a number known to those skilled in the art. In one example of the present invention, the number of the second openings 5 ​​is 4, and the interval between two adjacent second openings 5 ​​is 90°.

[0047] Through the above-mentioned technical solution, the present invention provides a negative electrode busbar for a cylindrical lithium battery with full tabs and a lithium battery. By disposing a first welding area at the center of the disc and a second welding area away from the center, the electrode sheets have space to expand during the charging and discharging process. The weld marks of the second welding area include multiple first circles, with the distance from the center of the first circle to the center of the disc being 50%-90% of the disc radius. This ensures welding strength, avoiding cold welds or insufficient welding strength, while also preventing overly tight welding that could cause electrode sheet breakage during charging and discharging. Compared with the prior art, the present invention has a simple structure, improves welding quality and efficiency, and ensures the electrical and safety performance of the battery.

[0048] The preferred embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, and these simple modifications all fall within the scope of protection of the present invention. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0049] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A negative electrode busbar for a cylindrical lithium battery with full tabs, characterized in that: The negative busbar comprises: disc body; A first welding area is provided at the center of the disc; The second welding area is arranged on the disk body and away from the center. The welding mark of the second welding area includes a plurality of first dots, and the plurality of first dots form a circular ring concentric with the disk body.

2. The negative busbar according to claim 1, wherein: The weld mark shape of the first welding area includes a plurality of second dots, and the second dots are convex upward.

3. The negative busbar according to claim 1, wherein: The distance between the center of the first circle and the center of the disk is 50%-90% of the radius of the disk.

4. The negative busbar according to claim 1, wherein: The first welding area is provided with a first opening, the edge of the disk body is provided with a second opening, and the first opening is in a semicircular shape.

5. The negative electrode busbar according to claim 4, characterized in that: The number of the second openings is four, and the interval between two adjacent second openings is 90°.

6. A full-tab cylindrical lithium battery, characterized in that: The lithium battery comprises: Battery electrode group; A positive busbar connected to one end of the battery electrode group for collecting current; A negative busbar is connected to the other end of the battery electrode group and is used to collect current. The negative busbar includes: disc body; A first welding area is provided at the center of the disc; The second welding area is arranged on the disk body and away from the center. The welding mark of the second welding area includes a plurality of first dots, and the plurality of first dots form a circular ring concentric with the disk body.

7. The lithium battery according to claim 6, characterized in that The weld mark shape of the first welding area includes a plurality of second dots, and the second dots are convex upward.

8. The lithium battery according to claim 6, characterized in that: The distance between the center of the first circle and the center of the disk is 50%-90% of the radius of the disk.

9. The lithium battery according to claim 6, characterized in that: The first welding area is provided with a first opening, the edge of the disk body is provided with a second opening, and the first opening is in a semicircular shape.

10. The lithium battery according to claim 9, characterized in that: The number of the second openings is four, and the interval between two adjacent second openings is 90°.

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