Lithium ion battery pack tab series welding method
By setting up additional welding areas and using welding protective tooling in the lithium-ion battery pack electrode series connection, the poor contact problems caused by the edges of the electrode overlapping areas are solved, the reliability and stability of welding are improved, and ignition and ablation are avoided.
Patent Information
- Application Number
- CN202510243347.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-03
- Publication Date
- 2025-06-06
AI Technical Summary
During the series welding process of the lithium-ion battery pack, due to the limitations of the welding process, the edges of the overlapping area of the lithium-ion battery pack are not welded, resulting in poor contact, which can easily lead to ignition and ablation.
During the series welding of the electrode ears of the lithium-ion battery pack, an additional welding area is set up at the edge area of the overlapping part of the electrode overlap, and a welding protective tool is used to fix the welding production line with fixed holes, and the hollow area is used for welding protection.
By adding welding points and using welding protective tooling, the poor contact problem of unwelded areas of the edge of the extreme ear when the battery pack is discharged at high rate, high frequency discharge or high current density is solved, and the reliability and stability of welding are improved, and ignition and ablation are avoided.
Smart Images
Figure CN120095414A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of lithium ion battery pack group welding, and in particular to a method for series welding of lithium ion battery pack tabs. Background Art
[0002] With the widespread application of lithium-ion batteries in electric vehicles, energy storage, power tools and other fields, the models and types of lithium-ion battery packs are increasing. A lithium-ion battery pack is an electrical unit with different electrical parameters formed by connecting lithium-ion battery cells in series and in parallel. The series electrical connection of lithium-ion battery tabs is an essential process for battery pack assembly. At present, there are two main methods for the electrical connection of tabs in battery packs. One is to use screws, and the other is welding. The welding methods are divided into laser welding, ultrasonic welding, resistance welding, etc. In the series welding of the tabs of lithium-ion battery packs, due to the limitations of the hot melting amount of the tabs and the welding process, usually the welding area only needs to meet the current flow index, and the overlapping areas of the tabs of two single cells in series will not be welded together, that is, the full welding process will not be adopted, but the welding parts will be in the form of strips (bands) or points. For example Figure 2 As shown, the lower battery tab (lower tab) is folded upward by 90°, and the upper battery tab (upper tab) is folded downward by 90°, thereby forming a tab overlap area available for welding on the busbar. The welding area in the tab overlap area available for welding includes four point-shaped welding locations. Correspondingly, the structure of the welding protective tooling is as follows Figure 3 As shown in the figure, the matching relationship between the welding protective tooling and the tabs, busbars and welding points to be welded is as follows Figure 4 As shown, the welding protective tooling is pressed on the edge areas of the two tabs and the busbar, and the middle area of the tab overlap part is hollowed out for welding. Figure 2 There are two areas where the tabs are overlapped or crimped but not melt-welded. In particular, due to the limitation of welding tooling, the edge of the tab overlap area will not be welded. Since the overlapped but unwelded area has poor contact, when the battery pack is discharged at a high rate, high frequency or the tab current density is high, the unwelded area at the edge of the tab is prone to ablation and sparking. That is, in the prior art, when lithium-ion battery packs are connected in groups in series, there are sparking and ablation problems caused by poor contact. Summary of the invention
[0003] In order to solve the above technical problems, the present invention provides a method for welding the pole tabs of a lithium-ion battery pack in series, comprising: when the lithium-ion battery pack is electrically connected in series, the upper pole tab and the lower pole tab form a welding pair that overlaps and is overlapped with each other, and an additional welding area is provided on the basis of the original welding area at the overlapping portion of the upper pole tab and the lower pole tab, and the additional welding area is located at the edge area of the overlapping portion of the upper pole tab and the lower pole tab.
[0004] The present invention has the following beneficial effects:
[0005] 1. By setting the position of the battery pack's tabs in series, the sparking and ablation problems that may occur during high-rate discharge of the battery pack can be solved.
[0006] 2. By setting the positions of the serial welding points of the battery pack tabs, the welding reliability and stability of the electrical connections with high current density and high frequency current characteristics such as the electrical connections of the battery pack tabs can be improved.
[0007] 3. Through the setting of the welding protection tooling structure, safe welding of the edge area of the series or parallel tabs can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Figure 1 A schematic diagram of the arrangement of the electrode tab welding points of the present invention;
[0009] Figure 2 A schematic diagram of a prior art electrode tab welding point;
[0010] Figure 3 A schematic diagram of a welding protective tooling structure in the prior art;
[0011] Figure 4 It is a schematic diagram of the relationship between the arrangement of welding points and the coordination of welding protective tooling in the prior art;
[0012] Figure 5 It is a schematic diagram of the first arrangement mode of the electrode ear series welding points and the welding effect when the present invention is actually used;
[0013] Figure 6 It is a schematic diagram of a second arrangement mode of the electrode ear series welding points and the welding effect when the present invention is actually used;
[0014] Figure 7 It is a schematic diagram of the welding protection tooling structure of the present invention;
[0015] Figure 8 It is a schematic diagram of the relationship between the welding point arrangement and the welding protection tooling of the present invention. DETAILED DESCRIPTION
[0016] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.
[0017] Taking soft-pack lithium ion as an example, the lithium ion battery pack terminal ear series welding method of the present invention is as follows Figure 1As shown, it includes setting welding points for overlapping the pole ears of lithium-ion batteries in series. When the soft-pack lithium-ion batteries are electrically connected in series, the positive or negative electrode of the lower battery (battery 1#) is folded upward by 90°, which is called the lower pole ear, and the negative or positive electrode of the upper battery (battery 2#) is folded downward by 90°, which is called the upper pole ear. The upper pole ear and the lower pole ear form a welding pair that overlaps and overlaps each other, and so on, to achieve the series connection relationship of the batteries. The overlapping part of the pole ears of the soft-pack lithium-ion battery when overlapping, needs to be welded to ensure the stability and low impedance characteristics of the electrical connection. In order to avoid sparking and ablation caused by poor contact in the unwelded area of the pole ear overlap when the battery pack is discharged at a high rate, discharged at a high frequency or when the current density of the pole ears is high, the lithium-ion battery pack pole ear series welding method of the present invention sets a supplementary welding point in the edge area of the overlapping part of the pole ear overlap, that is, an additional welding area is set on the basis of the original welding area. At the same time, in order to prevent the welding melt from damaging the battery body when the soft-pack lithium-ion battery tabs are welded in series, the present invention provides a welding protective tooling, which is generally a metal part or made of other materials with certain strength and high temperature resistance, and is fixed to the welding production line through the welding protective tooling fixing holes. When the tabs are welded, the welding protective tooling falls on the overlapping tabs, and the area where welding operations need to be performed is the hollow area of the welding protective tooling, that is, in the overlapping part of the tabs, the welding protective tooling presses the overlapping area of the tabs except the welding points. During welding, the welding protective tooling can protect the battery body while exposing the positions of the welding points that need to be welded, that is, it can cover the other parts of the battery body except the battery tabs and the connecting copper busbars.
[0018] In actual use, the arrangement of the terminal ear series welding points and the welding effect are as follows: Figure 5 , Figure 6 In order to achieve Figure 5 , Figure 6 The solder joints shown are soldered using Figure 7 The welding protection tooling shown in the figure. The welding operation area of the welding protection tooling is set to hollow out the original welding area and the additional welding area in the length direction of the pole ear. The relationship between the welding point arrangement of the present invention and the welding protection tooling is as follows Figure 8 As shown in the figure, the welding protection tooling is fixed to the welding production line through the welding protection tooling fixing hole. When the welding protection tooling falls on the two tabs to be welded, the busbar and the battery tabs can be pressed, and the original welding area and the additional welding area can be exposed to implement welding. The setting of the welding protection tooling can avoid the damage to the battery body caused by the laser or sputtered molten material when welding the overlapping edge positions of the tabs. Using this welding protection tooling for series welding of tabs can achieve Figure 5 , Figure 6 The welding point arrangement and welding effect are shown.
[0019] The above-mentioned lithium-ion battery pack tab series welding method can be applied to the welding of electrical connections with high current density and high-frequency current characteristics. The overlapping part of the two electrical connectors in the welding is provided with an additional welding area on the basis of the original welding area. The additional welding area is located at the edge area of the overlapping part of the two electrical connectors. Corresponding welding protection tooling is also provided for welding protection. The setting method of the welding protection tooling is the same as the setting method of the welding protection tooling for the series welding of the soft-pack lithium-ion battery tabs, which will not be repeated here.
[0020] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for welding the tabs of a lithium-ion battery pack in series, characterized in that: include: When the lithium-ion battery pack is electrically connected in series, the upper pole ear and the lower pole ear form a welding pair that overlaps and is overlapped with each other. An additional welding area is provided on the basis of the original welding area at the overlapping portion of the upper pole ear and the lower pole ear. The additional welding area is located at the edge area of the overlapping portion of the upper pole ear and the lower pole ear.
2. The method for serially welding the tabs of a lithium-ion battery pack according to claim 1, characterized in that: The additional welding area is located on both sides of the edge area of the overlapping part of the upper pole tab and the lower pole tab.
3. The method for series welding of tabs of a lithium-ion battery pack according to claim 1, characterized in that: Set up welding protective gear.
4. The method for series welding of tabs of a lithium-ion battery pack according to claim 3, characterized in that: The welding protective tooling is made of a material with certain strength and high temperature resistance.
5. The method for serially welding the tabs of a lithium-ion battery pack according to claim 3, characterized in that: The welding protective tooling is a metal part.
6. The method for serially welding the tabs of a lithium-ion battery pack according to claim 3, characterized in that: The welding operation area of the welding protective tooling is set to hollow out the original welding area and the additional welding area in the length direction of the pole ear.
7. The method for serially welding the tabs of a lithium-ion battery pack according to claim 3, characterized in that: The welding protective tooling is fixed to the welding production line through the welding protective tooling fixing holes. When the welding protective tooling falls on the two pole ears to be welded, the bus and the two battery pole ears are pressed, and the original welding area and the additional welding area are exposed to carry out welding.
8. The method for serially welding the tabs of a lithium-ion battery pack according to claim 6, characterized in that: The welding protective tooling is fixed on the welding production line through the welding protective tooling fixing holes. When the tabs are welded, the welding protective tooling falls on the overlapping tabs, and the area where welding operations are required is located in the hollow area of the welding protective tooling.
9. The method for serially welding the tabs of a lithium-ion battery pack according to claim 1, characterized in that: The lithium-ion battery pack tab series welding method is applied to the welding of electrical connections with high current density and high-frequency current characteristics. In the welding, an additional welding area is set on the overlapping part of two electrical connectors based on the original welding area, and the additional welding area is located at the edge area of the overlapping part of the two electrical connectors.
10. The method for serially welding the tabs of a lithium-ion battery pack according to claim 9, characterized in that: A welding protective tool is provided and fixed on the welding production line through the welding protective tool fixing holes. When the welding protective tool falls on two electrical connectors to be welded, the original welding area and the additional welding area are exposed.