Series-parallel connection assembly structure of ultra-miniature high-power lithium ion battery
By adopting a series-parallel assembly structure in micro lithium-ion batteries, the problem of space loss during the electrode welding process is solved, and the energy density and space utilization of the battery are improved.
Patent Information
- Application Number
- CN202411738151.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-29
- Publication Date
- 2025-02-28
AI Technical Summary
Existing micro lithium-ion batteries have space loss during the electrode welding process, resulting in low battery volume energy density.
The ultra-micro high-power lithium-ion battery is used to carry out ultrasonic welding of the electrode ear without electrode glue and the current collector of the stacked battery, cut off the excess welding part, fix the electrode ear position with insulating tape, and solder the connecting cable to the electrode ear, and finally use aluminum-plastic film to encapsulate it, and seal it with the cable lead-out position.
The space loss in the protruding position of the extreme ear welding is reduced, the energy density of the battery is increased, and the space utilization rate of the battery is reduced by 38.5%, effectively improving the space utilization rate and volume energy density.
Smart Images
Figure CN119542696A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of lithium ion batteries, and in particular to a series-parallel assembly structure of ultra-miniature high-power lithium ion batteries. Background Art
[0002] At present, micro batteries are mainly used in tiny electronic devices such as Bluetooth headsets, wearable smart devices, etc. Micro batteries generally use a winding process to improve the energy density of the battery. However, with the demand for high-power pulse weapon power supplies from micro drones, micro laser weapons, etc., the traditional winding process of micro power supplies cannot meet the demand. In the traditional assembly process of micro high-power lithium-ion batteries, in order to ensure the power performance and space utilization of lithium-ion batteries, an internal parallel stacking structure with the same side tabs is generally used. However, in the welding process between the battery cell and the tab, in order to ensure that the tab can withstand large current shocks, the following is generally used. Figure 2 The assembly structure shown in the figure is encapsulated with aluminum plastic film using the tab glue provided by the tab after the tab is welded. Figure 2 It can be seen that there is a lot of space loss from the welding position of the pole ear to the packaging position, resulting in low volume energy density of the battery. Secondly, during the use of ultra-micro lithium-ion batteries, the connecting cables are generally welded to the pole ears for lead-out use, so the welding and processing of the pole ears are crucial to the use of micro batteries. Summary of the invention
[0003] The present invention aims to provide a series-parallel assembly structure of ultra-miniature high-power lithium-ion batteries to solve the problem of space loss in the existing tab welding method, which leads to low battery volume energy density.
[0004] To solve the above technical problems, the present invention provides the following technical solutions: a series-parallel assembly structure of an ultra-micro high-power lithium-ion battery, comprising the following steps: first, ultrasonically welding a pole ear without pole ear glue to a current collector of a laminated battery, cutting off excess welded parts while welding, treating the surface of the battery cell with insulating tape, fixing the position of the pole ear on the surface of the battery cell, welding the connecting cable to the pole ear, and finally encapsulating the battery cell with an aluminum-plastic film, and sealing the cable lead-out position with a pole ear sealant.
[0005] Furthermore, the laminated battery is split into two cells for processing, the two cells are connected back to back in a tic-tac-toe parallel structure, the tabs of the two cells are back-welded, one tab is used to connect the tabs on the same side of the two cells, the connecting cable is welded to the middle of the tab, and the cell is sealed with an aluminum-plastic film.
[0006] Furthermore, two of the battery cells are connected in parallel in a back-to-back tic-tac-toe structure, the current collectors are pre-welded, the current collectors on the same side of the two battery cells are welded to the pole tabs, the connecting cables are welded to the middle of the pole tabs, the current collectors and the pole tabs are physically bent into a U shape to fit tightly against the battery cells, and finally sealed with an aluminum-plastic film.
[0007] Furthermore, the two groups of parallel-connected battery cells are again connected in parallel back to back, and can be fixed with insulating tape, or directly placed in aluminum-plastic film for packaging after welding, to assemble into a large-capacity parallel battery with four battery cells, and two multi-strand wires are welded between the two groups of pole ears on both sides of the battery cell to lead out the battery pole ears, and finally the battery cell is packaged with aluminum-plastic film, and the pole ear sealant is used to seal the cable lead-out position.
[0008] Furthermore, two or more cells of the large-capacity parallel battery are placed on the same side and connected in series using tabs, the positive and negative current collectors of the battery on the opposite sides are back-welded and then welded with leads, and finally the cells are packaged using aluminum-plastic film.
[0009] Beneficial effects of the present invention: BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Figure 1 A schematic diagram of the positive and negative electrode structure of the series-parallel assembly structure of the ultra-miniature high-power lithium-ion battery of the present invention;
[0011] Figure 2 It is a schematic diagram of the prior art means;
[0012] Figure 3 This is a schematic diagram of the back welding process of the micro battery in Example 1;
[0013] Figure 4 This is a schematic diagram of the cross-shaped parallel structure of micro batteries in Example 2;
[0014] Figure 5 This is a schematic diagram of the process flow of micro batteries in parallel in an embodiment;
[0015] Figure 6 This is a schematic diagram of the process flow of connecting multiple cells of a micro battery in series;
[0016] Figure 7 This is a schematic diagram of the process flow of micro battery series connection;
[0017] Figure 8 This is a data graph of a pulse test using a microbattery in Example 4;
[0018] Fig. 9 This is a graph showing the data from a pulse test using the microbattery of Example 5. DETAILED DESCRIPTION
[0019] The following is further described in detail through specific implementation methods:
[0020] Embodiment 1:
[0021] First, the pole ear without pole ear glue is ultrasonically welded to the current collector of the laminated battery by back welding. While ensuring the welding strength, the excess welding part is cut off, and the surface of the battery cell is treated with insulating tape. Then, the position of the pole ear is fixed on the surface of the battery cell, and the connecting cable is welded to the pole ear. Finally, the battery cell is packaged with aluminum-plastic film, and the pole ear sealant is used to seal the cable lead-out position. The advantage of this is that the space loss at the protruding position of the pole ear welding is reduced, the energy density of the battery is increased, and the position of the battery connection cable can be extended from any direction, which increases the battery usage options, such as Figure 3 shown. Figure 1 It is a schematic diagram of the positive and negative electrode structure. Figure 2 1 in the figure is the tab. After the tab is welded, the tab glue provided by the tab is used for aluminum-plastic film packaging. As can be seen from the figure, there is a large amount of space loss from the tab welding position to the packaging position, resulting in low battery volume energy density. Secondly, during the use of ultra-micro lithium-ion batteries, the connecting cables are generally welded to the tabs for lead-out use. Figure 1 , 2 Compared with the conventional battery solution, this solution has a 38.5% smaller volume, effectively improving space utilization.
[0022] Embodiment 2:
[0023] Example 2 is based on Example 1. When designing a battery with the same capacity, the battery is split into two cells for processing. The two cells are connected in parallel in a back-to-back tic-tac-toe pattern. After the two cell tabs are back-welded, one tab is used to connect the tabs on the same side of the two cells. The two cells are connected in parallel, the connecting cable is welded to the middle of the tab, and the cell is encapsulated with an aluminum-plastic film. The tab sealant is used to seal the cable lead-out position. The total thickness of the assembled battery remains unchanged, the cell welding assembly is simpler, and the space utilization rate of the cell is increased. Figure 4 As shown, compared Figure 2 Compared with the conventional battery solution, the volume of this solution has been reduced by 44.7%, effectively improving the space utilization.
[0024] Embodiment 3:
[0025] The welding and connection method described in Scheme 2 welds the pole ears on the four current collectors of the two battery cells. In order to further optimize the battery cell structure, Scheme 3 first pre-welds the current collector and then performs a U-shaped physical bend. It is found that both the positive and negative current collectors can achieve a 180° physical bend and the current collectors are not damaged. Therefore, when designing a battery with the same capacity as Scheme 1, Scheme 3 uses a back-to-back tic-tac-toe parallel structure of two battery cells. At the pole ear position, since it is divided into two battery cells, the number of connections between the current collector and the pole ear of each battery cell is reduced, and the current collector has stronger plasticity. By lengthening the current collector, after pre-welding the current collector, the current collectors on the same side of the two battery cells are welded to the pole ears, the connecting cable is welded to the middle of the pole ear, and the current collector and the pole ear are physically bent into a U shape. Finally, the battery cell is encapsulated with an aluminum-plastic film, and the pole ear sealant is used to seal the cable lead-out position. First, the same-side current collector welding adopted by this solution is easier to operate than back welding. Second, the thickness of a single battery cell is reduced, while the total battery cell thickness remains unchanged, further increasing the space utilization of the battery cell. Finally, the back welding method will use more tabs, causing the battery to increase in weight, while this solution only uses one tab. At the same time, the position of the battery connection cable can be extended from any direction, increasing the battery usage options. Figure 5 As shown, compared Figure 1 Compared with conventional battery solutions, this solution has a 45% reduction in volume and a 30% increase in volume energy density.
[0026] Embodiment 4:
[0027] Further optimization, the structural design of Example 3 can effectively improve the space utilization rate, and improve the volume energy density and power density of the micro battery. Example 4 is based on Example 3, and the two groups of parallel-connected battery cells are again connected back to back in parallel. They can be fixed with insulating tape, or they can be directly placed in aluminum-plastic film for packaging after welding is completed, and assembled into a large-capacity parallel battery with four battery cells. In the middle of the two groups of pole ears on both sides of the battery cell, two multi-strand wires are welded to lead out the battery pole ears. Finally, the battery cell is packaged with aluminum-plastic film, and the pole ear sealant is used to seal the cable lead-out position. First of all, the packaging material of the micro battery accounts for about 30% of the weight of the battery. Through Example 4, the two groups of batteries are connected in parallel for the second time, the battery thickness is doubled, and the capacity is doubled, but the internal resistance of the battery is reduced again due to the parallel structure. The packaging material of the battery is reduced by 20%-30% compared with two batteries. At the same capacity and volume, the energy density and power density are improved. Figure 6 As shown, the energy density of this solution is 50% higher than that of conventional batteries at the same volume.
[0028] Embodiment 5:
[0029] The micro-battery assembled by the structures of Examples 3 and 4 can also place the current collectors of two or more cells on the same side, connect them in series using tabs, perform back welding on the positive and negative current collectors of the battery on the opposite sides and then weld the leads, finally use aluminum-plastic film to encapsulate the cells, and use tab sealant to seal the cable lead-out position. Figure 7 shown.
[0030] The pulse test was carried out using the micro-batteries of Examples 4 and 5. The test results are as follows: Figure 8 , Fig. 9 As shown, the micro battery can provide multiple pulse currents of more than 200C in a low temperature environment of 0℃ and can be used in micro weapons and equipment.
[0031] The above is only an embodiment of the present invention, and the common knowledge such as the known specific structure and characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.
Claims
1. The series-parallel assembly structure of ultra-micro high-power lithium-ion batteries is characterized by , including the following steps: First, the pole tab without pole tab glue is ultrasonically welded to the current collector of the laminated battery. During welding, the excess welding part is cut off. The surface of the battery cell is treated with insulating tape, the position of the pole tab is fixed on the surface of the battery cell, and the connecting cable is welded to the pole tab. Finally, the battery cell is encapsulated with aluminum-plastic film, and the pole tab sealant is used for sealing at the cable lead-out position.
2. The series-parallel assembly structure of ultra-miniature high-power lithium-ion batteries according to claim 1, characterized in that: The laminated battery is split into two cells for processing, the two cells are connected back to back in a tic-tac-toe parallel structure, the tabs of the two cells are back-welded, one tab is used to connect the tabs on the same side of the two cells, the connecting cable is welded to the middle of the tab, and the cell is sealed with an aluminum-plastic film.
3. The series-parallel assembly structure of ultra-miniature high-power lithium-ion batteries according to claim 2, characterized in that: Two of the battery cells are connected in parallel in a back-to-back tic-tac-toe pattern, the current collectors are pre-welded, the current collectors on the same side of the two battery cells are welded to the pole tabs, the connecting cables are welded to the middle of the pole tabs, the current collectors and the pole tabs are physically bent into a U shape to fit closely against the battery cells, and finally sealed with an aluminum-plastic film.
4. The series-parallel assembly structure of ultra-miniature high-power lithium-ion batteries according to claim 3, characterized in that: The two groups of parallel-connected battery cells are connected back to back in parallel again. They can be fixed with insulating tape or directly placed in aluminum-plastic film for packaging after welding to assemble into a large-capacity parallel battery with four battery cells. Two multi-strand wires are welded between the two groups of pole ears on both sides of the battery cell to lead out the battery pole ears. Finally, the battery cell is packaged with aluminum-plastic film and sealed with pole ear sealant at the cable lead-out position.
5. The series-parallel assembly structure of ultra-miniature high-power lithium-ion batteries according to claim 4, characterized in that: The two or more cells of the large-capacity parallel battery are placed on the same side and connected in series using tabs. The positive and negative current collectors of the batteries on the opposite sides are back-welded and then welded with leads. Finally, the cells are packaged using an aluminum-plastic film.