Adaptive welding device for composite foil and tab

Abstract

The invention provides a composite foil and tab transfer welding device 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 invention, the foil in the roll welding and printing area is thinned, so that the thickness of the welding and printing area is obviously reduced, thereby improving the machinability of the pole piece in the subsequent working section and reducing the machinability of bending and the like of the battery cell tab; 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] The invention relates to the field of lithium ion batteries, and in particular to a transfer welding device for a composite foil material and a tab. Background Art

[0002] Composite current collector is a new type of current collector material composed of polymer materials and metals. It mainly collects current and carries positive and negative active materials. Current collector plays an indispensable role in lithium-ion batteries. On the one hand, it carries positive and negative active materials, and on the other hand, it collects and transmits the current generated by positive and negative active materials during the battery's charge and discharge process, reducing the battery's internal resistance while improving the battery's coulombic efficiency, cycle stability and rate performance.

[0003] The structure of the composite current collector is similar to a "sandwich" structure, with a base film (PP, PET, PI and other polymer materials) in the middle and copper or aluminum metal films on the outside. Composite current collectors have shown significant performance advantages over traditional metal current collectors. First, in terms of lightweight, since the density of polymer materials is much lower than that of metal materials, the weight of composite current collectors is lighter, which helps to increase the energy density of the battery. Secondly, from a cost-effectiveness perspective, the cost of polymer materials is generally lower than that of metals, so the use of composite current collectors can reduce the overall cost of battery materials. In terms of safety, the structural characteristics of the composite current collector make it safer in the puncture test and reduce the risk of internal short circuits in the battery. Finally, due to the use of thinner metal layers and lightweight polymer materials, the composite current collector can provide more space for the active materials inside the battery, further improving the energy density of the battery. These advantages make the composite current collector an effective solution to improve battery performance and reduce costs.

[0004] Tab transfer welding is an important step in the manufacture of composite foils in lithium batteries. Since the polymer material in the middle of the composite current collector makes the metal coatings on both sides unable to conduct, it is necessary to add a tab transfer welding process to bring the metal coatings on both sides together. During the welding process, one end of the two tab metal foils are welded to the two sides of the composite current collector respectively, and then the other ends of the two tab metal foils are overlapped and welded together, so that the conductive layers on both sides of the composite current collector are brought together.

[0005] Ultrasonic roll welding technology plays an important role in the transfer welding of the tab, because it uses the mechanical vibration energy of the ultrasonic frequency to connect the materials to be welded under the joint action of static pressure. This welding method does not generate high temperature and is suitable for the welding of composite current collectors and tabs, especially the welding of metals and polymer materials, the melting points of which are very different.

[0006] However, traditional tab transfer welding will cause the thickness of the weld mark area to increase significantly. This is mainly because the two layers of pure metal foil transferred on the surface of the composite foil significantly increase the thickness of the weld mark, which will affect the subsequent battery cell stacking process and the difficulty of tab welding. Excessively thick weld marks are also not conducive to the bending of the battery cell tabs.

[0007] To this end, we propose a transfer welding device for composite foil and tab to solve the problem of increased thickness in the weld print area. problem. Summary of the invention

[0008] The purpose of the present invention is to solve the shortcomings existing in the prior art. In order to achieve the above purpose, the present invention adopts the following technical solutions: A transfer welding device for composite foil and pole tabs comprises: a pole tab strip unwinding mechanism 1, on which a wide pole tab strip is rotatably mounted; a pole tab strip unwinding mechanism 2, on which a narrow pole tab strip is rotatably mounted; a thinning device, on which the wide pole tab strip and the narrow pole tab strip enter the thinning device through guide rollers, and the thinning device thins the edges of the wide pole tab strip and the narrow pole tab strip; a composite foil unwinding mechanism, on which a composite foil strip is rotatably mounted; a rolling welding device, on which the composite foil strip and the thinned wide pole tab strip and narrow pole tab strip enter the rolling welding device together through guide rollers, and the rolling welding device welds the wide pole tab strip, the narrow pole tab strip and the composite foil strip; and a rolling mechanism, on which the welded wide pole tab strip, the narrow pole tab strip and the composite foil strip are rolled.

[0009] Further 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 mounted on the base plate, a thinning roller and a pair of support rollers are rotatably mounted on the bearing bracket, the thinning roller is located in the middle of the pair of support rollers, a drive motor is fixedly mounted on the motor bracket, and the output end of the drive motor drives the thinning roller to rotate.

[0010] Further preferably, the outer end of the thinning roller is tapered, and the middle roller is a tapered thinning roller, which can avoid indentation or breakage of the foil.

[0011] Further preferably, the distance between the support roller and the thinning roller is adjustable to facilitate adjustment of the thinning thickness.

[0012] Further preferably, the roll welding device includes an ultrasonic generator, an ultrasonic transducer, an active roll welding head, a supporting 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, a driven roll welding head is installed below the active roll welding head, and the driven roll welding head is rotatably installed on the supporting shaft.

[0013] Further preferably, the ultrasonic generator and the supporting shaft are supported by a fixing frame.

[0014] Further preferably, the thickness of the composite foil strip is A, the thickness of the wide pole tab strip is greater than A / 2, the thickness of the thinned edge of the wide pole tab strip is B, and 2B=A.

[0015] Further preferably, the thickness of the narrow pole tab band is greater than A / 2, the thickness of the thinned edge of the narrow pole tab band is C, and 2C=A.

[0016] Further 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 pole tab strip, narrow pole tab strip and composite foil strip.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The present invention thins the foil in the roll welding weld mark area, so that the thickness at the weld mark is significantly reduced, thereby improving the processability of the subsequent process sections of the electrode piece and reducing the processability of the bending of the battery cell electrode ear; the thinned electrode ear and the composite foil electrode piece enter the ultrasonic roll welding device, and the three layers of foil are welded together, thereby realizing the electrical connection of the double-sided foil. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the process equipment of the present invention; Figure 2 The structure of the thinning device of the present invention is shown in FIG. Figure 1 ; Figure 3 The structure of the thinning device of the present invention is shown in FIG. Figure 2 ; Figure 4 It is a structural schematic diagram of the seam welding device of the present invention; Figure 5 It is a schematic diagram of the structure of the composite foil strip of the present invention; Figure 6 This is a schematic diagram of the structure of the narrow pole ear band after thinning in the present invention; Figure 7 It is a schematic diagram of the structure of the wide pole lug strip after thinning according to the present invention.

[0019] In the figure: a pole tab strip unwinding mechanism 1, a pole tab strip unwinding mechanism 2, a thinning device 3, a composite foil unwinding mechanism 4, a roll welding device 5, a winding mechanism 6, a wide pole tab strip 11, a narrow pole tab strip 21, a composite foil strip 41, an active material layer 42, a bottom plate 31, a motor bracket 32, a drive motor 33, a bearing bracket 34, a support roller 35, a thinning roller 36, 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. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0021] Reference Figure 1-Figure 7 , a transfer welding device for a composite foil and a tab, comprising: A pole tab strip unwinding mechanism 1, on which a wide pole tab strip 11 is rotatably mounted; a pole tab strip unwinding mechanism 2, on which a narrow pole tab strip 21 is rotatably mounted; a thinning device 3, on which the wide pole tab strip 11 and the narrow pole tab strip 21 enter the thinning device 3 through guide rollers, and the thinning device 3 thins the edges of the wide pole tab strip 11 and the narrow pole tab strip 21; a composite foil unwinding mechanism 4, on which a composite foil strip 41 is rotatably mounted; a rolling welding device 5, on which the composite foil strip 41 and the thinned wide pole tab strip 11 and narrow pole tab strip 21 enter the rolling welding device 5 through guide rollers, and the rolling welding device 5 welds the wide pole tab strip 11, the narrow pole tab strip 21 and the composite foil strip 41; a winding mechanism 6, on which the welded wide pole tab strip 11, the narrow pole tab strip 21 and the composite foil strip 41 are wound.

[0022] In one embodiment, the wide pole lug band 11 is installed on the pole lug band unwinding mechanism 1, and the narrow pole lug band 21 is installed on the pole lug band unwinding mechanism 22. In order to improve the space utilization rate, in the vertical direction, the pole lug band unwinding mechanism 22 is arranged at the upper left side of the thinning device 3, and the pole lug band unwinding mechanism 1 is arranged at the lower left side of the thinning device 3. The pole lug band unwinding mechanism 1 and the pole lug band unwinding mechanism 22 are provided with a limiting mechanism, and the limiting mechanism can prevent the wide pole lug band 11 and the narrow pole lug band 21 from being offset in the width direction during the unwinding process. A pair of guide rollers are respectively arranged in front of the left side of the thinning device 3. The wide pole lug band 11 and the narrow pole lug band 21 are adjusted in direction and tension by the guide rollers during the unwinding process, so that they can smoothly enter the thinning device 3, ensuring that the thinning position is accurate and not offset, thereby ensuring the thinning effect; The composite foil strip 41 is installed on the composite foil unwinding mechanism 4, and the wide pole tab strip 11 is wound under the composite foil strip 41 through the guide roller. From top to bottom, the narrow pole tab strip 21, the composite foil strip 41 and the wide pole tab strip 11 enter the rolling welding device 5 synchronously through the guide roller, and the thinned pole tab and the composite foil strip 41 enter the ultrasonic rolling welding to weld the three layers of foil together, thereby realizing the electrical connection of the double-sided foil.

[0023] In one embodiment, the upper and lower surfaces of the composite foil strip 41 are coated with an active material layer 42 except for the welding area, and finally the welded wide tab strip 11 , narrow tab strip 21 and composite foil strip 41 are rolled up by the rolling mechanism 6 .

[0024] The present invention thins the foil in the roll welding weld mark area, so that the thickness at the weld mark is significantly reduced, thereby improving the processability of the subsequent process sections of the electrode piece and reducing the processability of the bending of the battery cell electrode ear; the thinned electrode ear and the composite foil electrode piece enter the ultrasonic roll welding device, and the three layers of foil are welded together, thereby realizing the electrical connection of the double-sided foil.

[0025] The thinning device 3 includes a base plate 31, a motor bracket 32, a driving motor 33, a bearing bracket 34, a supporting roller 35 and a thinning roller 36; the motor bracket 32 ​​and the bearing bracket 34 are fixedly installed on the base plate 31, and a thinning roller 36 and a pair of supporting rollers 35 are rotatably installed on the bearing bracket 34, and the thinning roller 36 is located in the middle of the pair of supporting rollers 35. The driving motor 33 is fixedly installed on the motor bracket 32, and the output end of the driving motor 33 drives the thinning roller 36 to rotate. The outer end of the thinning roller 36 is conical, and the distance between the supporting roller 35 and the thinning roller 36 is adjustable.

[0026] In one embodiment, a thinning roller 36 is installed in the middle of the bearing bracket 34, and the thinning roller 36 is driven to rotate by the driving motor 33. The support rollers 35 on both sides of the thinning roller 36 can adjust the spacing up and down (for example, a slide rail and a slider are installed on the bearing bracket 34, and the support roller 35 is installed on the slider. By adjusting the position of the slider on the slide rail, the spacing can be adjusted; for example, 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 spacing. All adjustable structures are within this protection range and are not limited to the above embodiments), the narrow pole lug band 21 passes through the middle of the thinning roller 36 and the upper support roller 35, and the wide pole lug band 11 passes through the middle of the thinning roller 36 and the lower support roller 35. When the driving motor 33 drives the thinning roller 36 to rotate, the edges of the wide pole lug band 11 and the narrow pole lug band 2 are thinned.

[0027] In one embodiment, the intermediate roller is a tapered thinning roller 36 that can avoid indentation or breakage of the foil.

[0028] The roll welding device 5 includes an ultrasonic generator 51, an ultrasonic transducer 52, an active roll welding head 53, a supporting 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, the tail end of the ultrasonic transducer 52 is connected to the ultrasonic generator 51 through a connecting line, a driven roll welding head 55 is installed below the active roll welding head 53, and the driven roll welding head 55 is rotatably installed on the supporting shaft 54, and the ultrasonic generator 51 and the supporting shaft 54 ​​are supported by a fixed frame.

[0029] In one embodiment, from top to bottom, the narrow pole tab strip 21, the composite foil strip 41 and the wide pole tab strip 11 are synchronously introduced into the active rolling welding head 53 and the driven rolling welding head 55 through guide rollers, and the thinned pole tab and the composite foil strip 41 are introduced into the ultrasonic rolling welding through the rolling welding device 5, and the three layers of foil are welded together, thereby realizing the electrical connection of the double-sided foil. The guide roller on the left side of the rolling welding device 5 can effectively adjust the tension between the thinned pole tab and the composite foil strip 41, and can ensure that the composite foil formed by welding is not bent or wrinkled, and ensure that the weld mark position is accurate and not offset, thereby ensuring the welding effect.

[0030] The thickness of the composite foil strip 41 is A, the thickness of the wide pole tab strip 11 is greater than A / 2, the thickness of the edge of the wide pole tab strip 11 is thinned to B, 2B=A, the thickness of the narrow pole tab strip 21 is greater than A / 2, the thickness of the edge of the narrow pole tab strip 21 is thinned to C, 2C=A.

[0031] 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. The narrow pole tab strip 21 with a width of 3-9 mm and a thickness of 6-12 microns; the wide pole tab strip 11 with a width of 12-50 mm and a thickness of 6-12 microns are fed into a three-roll coordinated double constant spacing slit roller to thin the edge of the foil. The width of the thinned area is 1-5 mm, and the thickness of the composite foil strip 41 is 5-20 microns. The pole tab strip and the composite foil pole sheet material with thinned edges are rolled into the roll welding module, and the three are ultrasonically welded together. The weld mark width is 3-9 mm, and then the pole sheet material roll that has been rolled is reeled up.

[0032] 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. The winding shaft is used to wind up the welded wide pole tab strip 11, narrow pole tab strip 21 and composite foil strip 41.

[0033] In one embodiment, the winding shaft is driven to rotate by a winding motor, and the rotating winding shaft winds up the welded wide pole tab strip 11 , narrow pole tab strip 21 and composite foil strip 41 .

[0034] The present invention thins the foil in the roll welding weld mark area, so that the weld mark thickness is significantly reduced, thereby improving the processability of the subsequent process sections of the electrode piece and reducing the processability of the bending of the battery cell electrode ear. The thinned electrode ear and the composite foil electrode piece enter the ultrasonic roll welding, realizing the parallel connection of the circuit of the metal coating on both sides of the insulating layer, thereby realizing the electrical connection of the double-sided foil.

Claims

1. A transfer welding device for composite foil and tab, characterized in that: include: A first pole lug strip unwinding mechanism, on which a wide pole lug strip is rotatably mounted; A second pole lug strip unwinding mechanism, on which a narrow pole lug strip is rotatably mounted; A thinning device, wherein the wide pole tab strip and the narrow pole tab strip enter the thinning device through guide rollers, and the thinning device thins the edges of the wide pole tab strip and the narrow pole tab strip; A composite foil unwinding mechanism, on which a composite foil strip is rotatably mounted; A roll welding device, wherein the composite foil strip and the thinned wide pole tab strip and narrow pole tab strip enter the roll welding device together through guide rollers, and the roll welding device welds the wide pole tab strip, the narrow pole tab strip and the composite foil strip; A winding mechanism is used to wind up the wide pole tab strip, the narrow pole tab strip and the composite foil strip after welding.

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

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

4. The transfer welding device for composite foil and tab according to claim 2, characterized in that: The distance between the supporting roller and the thinning roller is adjustable.

5. The transfer welding device for composite foil and 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 supporting 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, a driven roll welding head is installed below the active roll welding head, and the driven roll welding head is rotatably installed on the supporting shaft.

6. The transfer welding device for composite foil and tab according to claim 5, characterized in that: The ultrasonic generator and the supporting shaft are supported by a fixing frame.

7. The transfer welding device for composite foil and tab according to claim 1, characterized in that: The thickness of the composite foil strip is A, the thickness of the wide pole tab strip is greater than A / 2, the thickness of the thinned edge of the wide pole tab strip is B, and 2B=A.

8. The transfer welding device for composite foil and tab according to claim 7, characterized in that: The thickness of the narrow pole tab band is greater than A / 2, the thickness of the thinned edge of the narrow pole tab band is C, and 2C=A.

9. The transfer welding device for composite foil and tab according to claim 1, characterized in that: The winding mechanism comprises a winding motor and a winding shaft, wherein the output end of the winding motor is connected to the winding shaft, and the winding shaft is used to wind up the welded wide pole tab strip, narrow pole tab strip and composite foil strip.

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