Adaptive welding device for composite foil and tab

Abstract

The utility model provides an adapter welding device for a composite foil and a tab, which is characterized in that a wide tab belt and a narrow tab belt enter a thinning device through a guide roller, and the edges of the wide tab belt and the narrow tab belt are thinned by the thinning device; the composite foil tape, the thinned wide tab tape and the thinned narrow tab tape enter the roll welding device through a guide roller, and the roll welding device is used for welding the wide tab tape, the narrow tab tape and the composite foil tape; the winding mechanism is used for winding the welded wide tab strip, narrow tab strip and composite foil strip; according to the utility model, the foil in the roll welding and printing area is thinned, so that the thickness of the welding and printing area is obviously reduced, the machinable performance of the pole piece in the subsequent working section is improved, and the machinable performance such as bending and the like of the battery cell tab is reduced; and the thinned tab and the composite foil pole piece enter an ultrasonic roll welding device, and the three layers of foils are welded together, so that the electric connection of the double-sided foils is realized.

Description

Technical Field

[0001] This utility model relates to the field of lithium-ion batteries, and in particular to a bonding device for composite foil and electrode tabs. Background Technology

[0002] Composite current collectors are a novel type of current collector material that combines polymer materials and metals. Their main function is to collect current and carry the positive and negative electrode active materials. Current collectors play an indispensable role in lithium-ion batteries. On the one hand, they carry the positive and negative electrode active materials; on the other hand, they collect and transmit the current generated by the positive and negative electrode active materials during charging and discharging, reducing the battery's internal resistance while improving its coulombic efficiency, cycle stability, and rate performance.

[0003] Composite current collectors have a structure similar to a "sandwich," with a base film (PP, PET, PI, etc.) in the middle and two outer copper or aluminum metal films. Compared to traditional metal current collectors, composite current collectors exhibit significant performance advantages. First, in terms of weight reduction, since the density of polymer materials is much lower than that of metal materials, composite current collectors are lighter, which helps to improve the energy density of the battery. Second, from a cost-effectiveness perspective, the cost of polymer materials is generally lower than that of metals, so using composite current collectors can reduce the overall cost of battery materials. In terms of safety, the structural characteristics of composite current collectors make them exhibit higher safety in nail penetration tests, reducing the risk of internal short circuits in the battery. Finally, due to the use of thinner metal layers and lightweight polymer materials, composite current collectors can provide more space for active materials inside the battery, further improving the battery's energy density. These advantages make composite current collectors an effective solution for improving battery performance and reducing costs.

[0004] Tab transfer welding is a crucial step in the manufacturing of lithium-ion batteries using composite foil. Because the polymer material in the middle of the composite current collector prevents the metal plating layers on both sides from conducting, a tab transfer welding process is needed to bring the two metal plating layers together. During the welding process, one end of each tab metal foil is welded to one side of the composite current collector, and then the other ends of the two tab metal foils are overlapped and welded together, thus bringing the conductive layers on both sides of the composite current collector together.

[0005] Ultrasonic roll welding technology plays an important role in electrode adapter welding because it utilizes the mechanical vibration energy of ultrasonic frequencies to join the materials being welded under the combined action of static pressure. This welding method does not generate high temperatures and is suitable for welding composite current collectors to electrodes, especially for welding metals and polymer materials with very different melting points.

[0006] However, traditional tab transfer soldering leads to a significant increase in the thickness of the solder area. This is mainly because the two layers of pure metal foil transferred to the surface of the composite foil significantly increase the thickness of the solder area. This will affect the subsequent cell stacking process and the difficulty of the tab welding process. Excessively thick solder is also not conducive to the bending of the cell tab.

[0007] To address this issue, we propose a composite foil-to-tab transfer welding device to solve the problem of increased soldering thickness.

[0008] The problem. Utility Model Content

[0009] The purpose of this utility model is to overcome the shortcomings of the existing technology. To achieve the above objective, this utility model adopts the following technical solution:

[0010] A bonding device for composite foil and electrode tabs includes: an electrode tab unwinding mechanism one, on which a wide electrode tab is rotatably mounted; an electrode tab unwinding mechanism two, on which a narrow electrode tab is rotatably mounted; a thinning device, on which the wide and narrow electrode tabs enter through guide rollers, and the thinning device thins the edges of the wide and narrow electrode tabs; a composite foil unwinding mechanism, on which a composite foil strip is rotatably mounted; a roll welding device, on which the composite foil strip and the thinned wide and narrow electrode tabs enter together through guide rollers, and the roll welding device welds the wide and narrow electrode tabs and the composite foil strip; and a winding mechanism, on which the winding mechanism winds the welded wide and narrow electrode tabs and the composite foil strip.

[0011] More preferably, the thinning device includes a base plate, a motor bracket, a drive motor, a bearing bracket, a support roller, and a thinning roller; the motor bracket and the bearing bracket are fixedly installed on the base plate, the thinning roller and a pair of support rollers are rotatably installed on the bearing bracket, the thinning roller is located in the middle of the pair of support rollers, the drive motor is fixedly installed on the motor bracket, and the output end of the drive motor drives the thinning roller to rotate.

[0012] More preferably, the outer end of the thinning roller is tapered and the middle roller is tapered, which can prevent foil indentation or breakage.

[0013] More preferably, the distance between the support roller and the thinning roller is adjustable, which facilitates the adjustment of the thinning thickness.

[0014] More preferably, the roll welding device includes an ultrasonic generator, an ultrasonic transducer, an active roll welding head, a support shaft, and a driven roll welding head; the output end of the ultrasonic transducer is connected to the active roll welding head, the tail end of the ultrasonic transducer is connected to the ultrasonic generator via a connecting line, and a driven roll welding head is installed below the active roll welding head, the driven roll welding head being rotatably mounted on the support shaft.

[0015] More preferably, the ultrasonic generator and the support shaft are supported by a fixing frame.

[0016] More preferably, the thickness of the composite foil strip is A, the thickness of the wide ear loop is greater than A / 2, the thickness of the thinned edge of the wide ear loop is B, and 2B=A.

[0017] More preferably, the thickness of the narrow ear loop is greater than A / 2, the thickness of the thinned edge of the narrow ear loop is C, and 2C=A.

[0018] More preferably, the winding mechanism includes a winding motor and a winding shaft, the output end of the winding motor is connected to the winding shaft, and the winding shaft winds up the welded wide tab strip, narrow tab strip and composite foil strip.

[0019] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0020] This invention thins the foil in the roll welding area, significantly reducing the thickness of the weld, thereby improving the processability of the electrode in subsequent processes and reducing the bending and other processability issues of the battery cell tabs. The thinned tabs and composite foil electrode are then fed into an ultrasonic roll welding device to weld the three layers of foil together, thus achieving electrical connection between the double-sided foil. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the process equipment of this utility model;

[0022] Figure 2 This is a schematic diagram of the thinning device of this utility model. Figure 1 ;

[0023] Figure 3 This is a schematic diagram of the thinning device of this utility model. Figure 2 ;

[0024] Figure 4 This is a schematic diagram of the structure of the roll welding device of this utility model;

[0025] Figure 5 This is a schematic diagram of the composite foil strip of this utility model;

[0026] Figure 6 This is a schematic diagram of the thinned narrow electrode ear strap structure of this utility model;

[0027] Figure 7 This is a schematic diagram of the thinned wide ear strap structure of this utility model.

[0028] In the diagram: 1. Electrode belt unwinding mechanism 1; 2. Electrode belt unwinding mechanism 2; 3. Thinning device; 4. Composite foil unwinding mechanism; 5. Roll welding device; 6. Winding mechanism; 11. Wide electrode belt; 21. Narrow electrode belt; 41. Composite foil belt; 42. Active material layer; 31. Base plate; 32. Motor bracket; 33. Drive motor; 34. Bearing bracket; 35. Support roller; 36. Thinning roller; 51. Ultrasonic generator; 52. Ultrasonic transducer; 53. Active roll welding head; 54. Support shaft; 55. Driven roll welding head. Detailed Implementation

[0029] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0030] Reference Figures 1-7 A bonding device for composite foil and electrode tabs, comprising:

[0031] A first electrode unwinding mechanism 1, on which a wide electrode strip 11 is rotatably mounted; a second electrode unwinding mechanism 2, on which a narrow electrode strip 21 is rotatably mounted; a thinning device 3, on which the wide electrode strip 11 and the narrow electrode strip 21 enter through guide rollers, and the thinning device 3 thins the edges of the wide electrode strip 11 and the narrow electrode strip 21; a composite foil unwinding mechanism 4, on which a composite foil strip 41 is rotatably mounted; a roll welding device 5, on which the composite foil strip 41 and the thinned wide electrode strip 11 and narrow electrode strip 21 enter through guide rollers, and the roll welding device 5 welds the wide electrode strip 11, the narrow electrode strip 21 and the composite foil strip 41; and a winding mechanism 6, on which the winding mechanism 6 winds up the welded wide electrode strip 11, narrow electrode strip 21 and composite foil strip 41.

[0032] In one embodiment, the wide tab 11 is mounted on the tab unwinding mechanism 1, and the narrow tab 21 is mounted on the tab unwinding mechanism 2. To improve space utilization, in the vertical direction, the tab unwinding mechanism 2 is positioned above the left side of the thinning device 3, and the tab unwinding mechanism 1 is positioned below the left side of the thinning device 3. The tab unwinding mechanism 1 and the tab unwinding mechanism 2 are equipped with a limiting mechanism. The limiting mechanism can prevent the wide tab 11 and the narrow tab 21 from shifting in the width direction during the unwinding process. A pair of guide rollers are respectively provided in front of the left side of the thinning device 3. During the unwinding process, the wide tab 11 and the narrow tab 21 adjust their direction and tension through the guide rollers so that they can smoothly enter the thinning device 3, ensuring that the thinning position is accurate and does not shift, thereby ensuring the thinning effect.

[0033] The composite foil strip 41 is installed on the composite foil unwinding mechanism 4. The wide tab strip 11 is wound around the bottom of the composite foil strip 41 through the guide roller. From top to bottom, the narrow tab strip 21, the composite foil strip 41 and the wide tab strip 11 enter the roll welding device 5 simultaneously through the guide roller. After the thinned tabs and the composite foil strip 41 enter the ultrasonic roll welding, the three layers of foil are welded together, thereby realizing the electrical connection of the double-sided foil.

[0034] In one embodiment, except for the welding area, the upper and lower surfaces of the composite foil strip 41 are coated with an active material layer 42, and finally the welded wide tab strip 11, narrow tab strip 21 and composite foil strip 41 are wound up by the winding mechanism 6.

[0035] This invention thins the foil in the roll welding area, significantly reducing the thickness of the weld, thereby improving the processability of the electrode in subsequent processes and reducing the bending and other processability issues of the battery cell tabs. The thinned tabs and composite foil electrode are then fed into an ultrasonic roll welding device to weld the three layers of foil together, thus achieving electrical connection between the double-sided foil.

[0036] The thinning device 3 includes a base plate 31, a motor bracket 32, a drive motor 33, a bearing bracket 34, a support roller 35, and a thinning roller 36. The motor bracket 32 ​​and the bearing bracket 34 are fixedly installed on the base plate 31. The thinning roller 36 and a pair of support rollers 35 are rotatably installed on the bearing bracket 34. The thinning roller 36 is located in the middle of the pair of support rollers 35. The drive motor 33 is fixedly installed on the motor bracket 32. The output end of the drive motor 33 drives the thinning roller 36 to rotate. The outer end of the thinning roller 36 is tapered. The distance between the support roller 35 and the thinning roller 36 is adjustable.

[0037] In one embodiment, a thinning roller 36 is installed in the middle of the bearing bracket 34. The thinning roller 36 is driven to rotate by the drive motor 33. The support rollers 35 on both sides of the thinning roller 36 can be adjusted up and down in distance (e.g., a slide rail and a slider are installed on the bearing bracket 34, and the support roller 35 is installed on the slider. The distance can be adjusted by adjusting the position of the slider on the slide rail; or a waist-shaped adjustment groove is opened on the bearing bracket 34, and the support roller 35 can be adjusted up and down in the adjustment groove to adjust the distance. All adjustable structures are within this protection range and are not limited to the above embodiment). The narrow tab 21 passes through the middle of the thinning roller 36 and the upper support roller 35, and the wide tab 11 passes through the middle of the thinning roller 36 and the lower support roller 35. When the drive motor 33 drives the thinning roller 36 to rotate, the edges of the wide tab 11 and the narrow tab 2 are thinned.

[0038] In one embodiment, the intermediate roller is a tapered thinning roller 36, which can prevent foil indentation or breakage.

[0039] The roll welding device 5 includes an ultrasonic generator 51, an ultrasonic transducer 52, an active roll welding head 53, a support shaft 54, and a driven roll welding head 55. The output end of the ultrasonic transducer 52 is connected to the active roll welding head 53, and the tail end of the ultrasonic transducer 52 is connected to the ultrasonic generator 51 through a connecting line. The driven roll welding head 55 is installed below the active roll welding head 53, and the driven roll welding head 55 is rotatably mounted on the support shaft 54. The ultrasonic generator 51 and the support shaft 54 ​​are supported by a fixing frame.

[0040] In one embodiment, the narrow tab strip 21, composite foil strip 41, and wide tab strip 11, from top to bottom, are simultaneously fed into the active welding head 53 and the driven welding head 55 via guide rollers. The thinned tabs and composite foil strip 41 are then fed into the ultrasonic welding device 5 to weld the three layers of foil together, thereby achieving electrical connection between the two sides of the foil. The guide roller on the left side of the welding device 5 can effectively adjust the tension between the thinned tabs and composite foil strip 41, ensuring that the welded composite foil does not bend or wrinkle, and that the welding mark position is accurate and does not deviate, thus ensuring the welding effect.

[0041] The thickness of the composite foil strip 41 is A, the thickness of the wide ear strip 11 is greater than A / 2, the thickness of the edge of the wide ear strip 11 is B, and 2B=A; the thickness of the narrow ear strip 21 is greater than A / 2, the thickness of the edge of the narrow ear strip 21 is C, and 2C=A.

[0042] In one embodiment, the composite foil strip 41, except for the welding area, has an active material layer 42 coated on its upper and lower surfaces. A narrow electrode strip 21 with a width of 3-9 mm and a thickness of 6-12 micrometers is passed through a three-roller synergistic double constant-gap slit roller to thin the foil edge. The width of the thinned area is 1-5 mm, and the thickness of the composite foil strip 41 is 5-20 micrometers. The edge-thinned electrode strip and the composite foil electrode material are then threaded into the roll welding module and ultrasonically welded together. The weld width is 3-9 mm. Finally, the roll welded electrode material is wound up.

[0043] The winding mechanism 6 includes a winding motor and a winding shaft. The output end of the winding motor is connected to the winding shaft, and the winding shaft winds up the welded wide tab 11, narrow tab 21 and composite foil 41.

[0044] In one embodiment, a winding motor drives a winding shaft to rotate, and the rotating winding shaft winds up the welded wide tab 11, narrow tab 21, and composite foil 41.

[0045] This invention reduces the thickness of the foil in the roll welding area, thereby improving the machinability of subsequent processes of the electrode sheet and reducing the machinability of the battery cell tabs, such as bending. The thinned tabs and composite foil electrode sheets are then subjected to ultrasonic roll welding, which realizes the parallel circuit of the metal plating on both sides of the insulation layer, thus achieving the electrical connection of the double-sided foil.

Claims

1. A device for connecting and welding composite foil and electrode tabs, characterized in that, include: A first electrode ear unwinding mechanism, on which a wide electrode ear is rotatably mounted; A second electrode ear unwinding mechanism is provided, on which a narrow electrode ear is rotatably mounted; A thinning device is used to thin the edges of the wide and narrow ear straps via guide rollers. A composite foil unwinding mechanism, wherein a composite foil strip is rotatably mounted on the composite foil unwinding mechanism; In the roll welding device, the composite foil strip and the thinned wide and narrow electrode strips are fed into the roll welding device together via guide rollers, and the roll welding device welds the wide electrode strip, the narrow electrode strip and the composite foil strip. A winding mechanism is used to wind up the welded wide tab strip, narrow tab strip, and composite foil strip.

2. The bonding device for composite foil and electrode tab according to claim 1, characterized in that, The thinning device includes a base plate, a motor bracket, a drive motor, a bearing bracket, a support roller, and a thinning roller. The motor bracket and the bearing bracket are fixedly installed on the base plate. The thinning roller and a pair of support rollers are rotatably installed on the bearing bracket. The thinning roller is located in the middle of the pair of support rollers. The drive motor is fixedly installed on the motor bracket. The output end of the drive motor drives the thinning roller to rotate.

3. The bonding device for composite foil and electrode tab according to claim 2, characterized in that, The outer end of the thinning roller is tapered.

4. The bonding device for composite foil and electrode tab according to claim 2, characterized in that, The distance between the support roller and the thinning roller is adjustable.

5. The bonding device for composite foil and electrode tab according to claim 1, characterized in that, The roll welding device includes an ultrasonic generator, an ultrasonic transducer, an active roll welding head, a support shaft, and a driven roll welding head; the output end of the ultrasonic transducer is connected to the active roll welding head, the tail end of the ultrasonic transducer is connected to the ultrasonic generator through a connecting line, and the driven roll welding head is installed below the active roll welding head, and the driven roll welding head is rotatably mounted on the support shaft.

6. The bonding device for composite foil and electrode tab according to claim 5, characterized in that, The ultrasonic generator and the support shaft are supported by a mounting bracket.

7. The bonding device for composite foil and electrode tab according to claim 1, characterized in that, The thickness of the composite foil strip is A, the thickness of the wide ear loop is greater than A / 2, the thickness of the edge of the wide ear loop being thinned is B, and 2B=A.

8. The bonding device for composite foil and electrode tab according to claim 7, characterized in that, The thickness of the narrow ear loop is greater than A / 2, and the thickness of the thinned edge of the narrow ear loop is C, where 2C = A.

9. The bonding device for composite foil and electrode tab according to claim 1, characterized in that, The winding mechanism includes a winding motor and a winding shaft. The output end of the winding motor is connected to the winding shaft, and the winding shaft winds up the welded wide tab strip, narrow tab strip, and composite foil strip.

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