Composite current collector welding method and apparatus

Abstract

The present application relates to the technical field of ultrasonic welding, and in particular to a composite current collector welding method and device, wherein the method uses a first unwinding mechanism for unwinding narrow foil, a second unwinding mechanism for unwinding wide foil, and a welding device arranged after the composite foil pole piece, narrow foil and wide foil are attached, comprising: a tension control process, the narrow foil unwound from the first unwinding mechanism and the wide foil unwound from the second unwinding mechanism are subjected to tension control and guided to attach to the composite foil pole piece unwound from a third unwinding mechanism by a third roller shaft set; a welding process, the narrow foil and the wide foil after being attached by the third roller shaft set are welded, and the deviation range of the narrow foil and the wide foil during welding is controlled. The rollers with different inclination angles and rotating speeds in the third roller shaft set increase the friction between the foils, thereby effectively inhibiting the relative displacement of the narrow foil and the wide foil during the welding process.

Description

Technical Field

[0001] This invention relates to the field of ultrasonic welding technology, and in particular to a composite current collector welding method and apparatus. Background Technology

[0002] In the battery manufacturing field, with continuous technological advancements, the application of composite current collectors is becoming increasingly widespread. Current composite current collector welding primarily employs a transfer welding method, which involves welding two layers of traditional foil to the composite current collector. This process typically uses a combination of two different foils, one narrower at the top and one wider at the bottom. During welding, the narrow foil and the wide foil are positioned on the top and bottom sides of the composite current collector, respectively, forming a multi-layered structure. When the welding mechanism is operating, the welding head is aligned with the overlapping area of ​​the foil and the composite current collector, applying pressure and generating ultrasonic energy to achieve a strong weld between the foil and the composite current collector. Simultaneously, tension control during the welding process relies heavily on the coordination of the unwinding mechanism and guide rollers. By adjusting the unwinding speed and the angle of the guide rollers, the tension of the foil is maintained within a certain range to ensure the stability of the weld quality.

[0003] However, existing composite current collector welding technologies face several pressing issues. Due to the differences in physical dimensions and mechanical properties between the two foil materials (narrower at the top and wider at the bottom), drift is prone to occur during welding. Specifically, during welding, the narrow and wide foil materials, due to their different tensions and the combined effects of the welding head pressure and ultrasonic welding vibrations, are susceptible to relative displacement. This drift leads to dimensional instability in the weld, consequently affecting battery performance and safety. Furthermore, the heat and mechanical stress generated during welding can also damage the structural integrity of the composite current collector, further reducing battery performance and lifespan. These problems are particularly prominent in applications with extremely high battery performance requirements, such as electric vehicles and portable electronic devices, limiting the further development and application of composite current collector technology. Summary of the Invention

[0004] Therefore, the technical problem this invention aims to solve is that, due to the differences in physical dimensions and mechanical properties between the two foil materials (narrower at the top and wider at the bottom), drift is prone to occur during the welding process. Specifically, during welding, the narrow and wide foil materials are easily displaced relative to each other due to their different tensions and the combined effects of the welding head pressure and ultrasonic welding vibration. This drift leads to instability in the weld dimensions, thereby affecting the battery's performance and safety.

[0005] The above-mentioned technical problems are solved by the following technical solution: This invention proposes a composite current collector welding method, using: a first unwinding mechanism for unwinding narrow foil, a second unwinding mechanism for unwinding wide foil, and a welding device disposed after the composite foil electrode, narrow foil, and wide foil are bonded together, comprising: The tension control process controls the tension of the narrow foil released from the first unwinding mechanism and the wide foil released from the second unwinding mechanism, and guides them to the third roller group to bond with the composite foil electrode sheet released from the third unwinding mechanism. The welding process involves welding the narrow foil and the wide foil after they have been bonded together by the third roller assembly, and controlling the deviation range during the welding of the narrow foil and the wide foil.

[0006] In a preferred embodiment of the composite current collector welding method of the present invention: the third roller group includes, in sequence along the processing direction, an extrusion roller group, an adjusting roller group, a welding mechanism, a first transition roller, a smoothing roller group, a second transition roller, and a take-up roller. The extrusion roller assembly includes an upper extrusion roller shaft and a lower extrusion roller shaft stacked on top of each other; The adjusting roller group includes adjusting roller one, adjusting roller two, and adjusting roller three; The welding mechanism includes a welding head and a base; The smoothing roller assembly includes a stationary roller and a lower pressure roller.

[0007] In a preferred embodiment of the composite current collector welding method of the present invention: the tilt angles of the first adjusting roller, the second adjusting roller and the third adjusting roller relative to the horizontal plane are C1, C2 and C3, respectively, wherein C1 is 60°–95°, C2 is 90°–120° and C3 is 120°–170°.

[0008] In a preferred embodiment of the composite current collector welding method of the present invention: the linear velocities of the adjusting roller one, adjusting roller two, and adjusting roller three satisfy the following relationship: The linear velocity V2 of adjusting roller 2 is greater than the linear velocity V3 of adjusting roller 3. The linear velocity V1 of adjusting roller one is less than the linear velocity V2 of adjusting roller two. The linear velocity V1 of adjusting roller one is less than or equal to the linear velocity V3 of adjusting roller three. Furthermore, V1, V2, and V3 are all within the range of 1-3 m / min; The difference between V2 and V3 is in the range of 0.05-0.3 m / min; The difference between V2 and V1 is in the range of 0.05-0.3 m / min.

[0009] In a preferred embodiment of the composite current collector welding method of the present invention: a first tension value T1 is formed on the foil between the first adjusting roller and the second adjusting roller; A second tension value T2 is formed on the foil between the second and third adjusting rollers; The first tension value T1 is less than the second tension value T2.

[0010] In a preferred embodiment of the composite current collector welding method of the present invention: the welding pressure applied by the welding head is 50N–200N, and the base is provided with a buffer pad and a heat dissipation channel.

[0011] In a preferred embodiment of the composite current collector welding method of the present invention: the lower pressure roller in the smoothing roller group is made of ceramic material, and a cylinder-driven lowering mechanism is provided between the lower pressure roller and the fixed roller. The lowering pressure of the lowering mechanism can be adjusted in the range of 1N–900N.

[0012] In a preferred embodiment of the composite current collector welding method of the present invention: in the tension control process, the first unwinding mechanism is provided with upper roller 1, upper roller 2, upper roller 3, upper roller 4, upper roller 5, upper roller 6, upper roller 7, upper roller 8, and upper roller 9 in sequence along the processing direction of the narrow foil material; The second unwinding mechanism is provided with lower roller 1, lower roller 2, lower roller 3, lower roller 4, lower roller 5, lower roller 6, lower roller 7, lower roller 8, and lower roller 9 in sequence along the processing direction of the wide foil material.

[0013] In a preferred embodiment of the composite current collector welding method of the present invention: the width of the narrow foil is 5–9 mm, and the tension of the narrow foil is 3 N–10 N; The width of the wide foil is 10–50 mm, and the tension of the wide foil is 3N–30N; The width of the composite foil electrode sheet is 55–700 mm, and the unwinding tension of the composite foil electrode sheet is 20 N–120 N.

[0014] In a preferred embodiment of the composite current collector welding method of the present invention: in the tension control process, a correction device is also provided, the correction device including a photoelectric sensor and a correction execution mechanism, the correction execution mechanism being located after the upper roller nine and the lower roller nine and before the third roller shaft group.

[0015] The above-mentioned technical problems are solved by the following technical solution: The present invention also proposes a composite current collector welding device, wherein the composite current collector welding device is a composite current collector welding device that implements the above method.

[0016] The beneficial effects of this invention are as follows: effectively suppressing drift: by setting rollers with different tilt angles and rotation speeds in the third roller group, the friction between the foils is increased, thereby effectively suppressing the relative displacement of narrow and wide foils during the welding process. This solves the drift problem caused by differences in physical dimensions and mechanical properties, and ensures the stability of the welding dimensions.

[0017] High-precision welding control: During the welding process, a servo motor is used to control the movement of the foil, and combined with the precise pressure applied by the welding head of the welding machine, the welding deviation is controlled within ±0.01mm. This high-precision control not only improves the welding quality, but also significantly improves the performance and safety of the battery.

[0018] Reduce welding stress and heat damage: The welding mechanism is equipped with buffer pads and heat dissipation channels, which can effectively reduce mechanical stress and heat accumulation during the welding process, protect the structural integrity of the composite current collector, and further extend the battery's service life.

[0019] Improving surface quality: The ceramic material pressure roller in the smoothing process works in conjunction with the fixed roller to effectively remove burrs generated after welding, improve the quality and smoothness of the welded surface, and facilitate the smooth progress of subsequent processes.

[0020] In summary, by combining the above-mentioned technical features, the present invention successfully solves the problems of drift, dimensional instability, and stress damage existing in the welding process of composite current collectors in the prior art, significantly improving welding quality and battery performance. It is particularly suitable for applications with extremely high battery performance requirements, such as electric vehicles and portable electronic devices. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention. Wherein: Figure 1 The process of the present invention is shown. Figure 1 ; Figure 2 The process of the present invention is shown. Figure 2 ; Figure 3 A schematic diagram of the adjusting roller assembly of the present invention is shown. Figure 1 ; Figure 4 A schematic diagram of the adjusting roller assembly of the present invention is shown. Figure 2 ; Figure 5 A schematic diagram of the adjusting roller assembly of the present invention is shown. Figure 3 .

[0022] 100. First unwinding mechanism; 101. Upper roller one; 102. Upper roller two; 103. Upper roller three; 104. Upper roller four; 105. Upper roller five; 106. Upper roller six; 107. Upper roller seven; 108. Upper roller eight; 109. Upper roller nine; 200. Second unwinding mechanism; 201. Lower roller one; 202. Lower roller two; 203. Lower roller three; 204. Lower roller four; 205. Lower roller five; 206. Lower roller six; 207. Lower roller seven; 208. Lower roller eight; 209. Lower roller nine; 300. Third unwinding mechanism; 400. Third roller group; 401. Extrusion roller group; 401a. Upper extrusion roller shaft; 401b. Lower extrusion roller shaft; 402. Adjusting roller group; 402a. Adjusting roller one; 402b. Adjusting roller two; 402c. Adjusting roller three; 403. Welding mechanism; 403a. Welding head; 403b. Base; 404. Transition roller one; 405. Smoothing roller group; 405a. Fixed roller; 405b. Lower pressure roller; 406. Transition roller two; 407. Take-up roller; m, wide foil; l, narrow foil; n, composite foil electrode. Detailed Implementation

[0023] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0024] The terminology used in this invention is that which is currently widely used in the art in consideration of the function of the invention; however, these terms may vary according to the intent of those skilled in the art, precedent, or new technology in the art. Furthermore, specific terms may be chosen by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the invention. Therefore, the terms used in this specification should not be construed as simple names, but rather based on their meanings and the overall description of the invention.

[0025] Reference Figures 1-5 This embodiment provides a composite current collector welding method, using: a first unwinding mechanism 100 for unwinding narrow foil l, a second unwinding mechanism 200 for unwinding wide foil m, and a welding mechanism 403 disposed after the composite foil electrode n, narrow foil l, and wide foil m are bonded together. The welding mechanism includes a tension control step S100, which controls the tension of the narrow foil l unwound from the first unwinding mechanism 100 and the wide foil m unwound from the second unwinding mechanism 200, and guides them to a third roller group 400 for bonding; and a welding step S200, which welds the narrow foil l and wide foil m bonded by the third roller group 400, and controls the deviation range of the narrow foil l and wide foil m during welding.

[0026] In this embodiment, a composite current collector welding method specifically involves a first unwinding mechanism 100 and a second unwinding mechanism 200 for unwinding narrow foil l and wide foil m, and a welding mechanism 403 disposed after the composite foil electrode n, narrow foil l, and wide foil m are bonded together. The method includes two main steps: a tension control step S100 and a welding step S200.

[0027] Tension control process S100: First, narrow foil l is released from the first unwinding mechanism 100, wide foil m is released from the second unwinding mechanism 200, and composite foil electrode n is released from the third unwinding mechanism 300. Narrow foil l and wide foil m pass through independent tension control systems. These systems achieve precise tension control through multiple rollers and guide the foils to the third roller group 400 for bonding. The third roller group 400 consists of a series of rollers with different tilt angles and rotational speeds, used to adjust the angle of the foils and increase friction to prevent misalignment during welding. Specifically, the tilt angles of adjusting roller one 402a, adjusting roller two 402b, and adjusting roller three 402c are C1 60°–95°, C2 90°–120°, and C3 120°–170°, respectively. The different rotational speeds of each roller increase the friction between the foils, suppressing misalignment.

[0028] Welding process S200: Next, the narrow foil l and wide foil m, after being bonded by the third roller group 400, enter the welding area. Here, a welding mechanism 403 is used. The welding head 403a of the welding machine applies a pressure of 50N–200N, and the base 403b of the welding machine is equipped with a buffer pad and heat dissipation channels to reduce welding vibration and heat accumulation. The welding mechanism 403 welds the three foils together to form a multi-layer composite foil, ensuring that the welding deviation is controlled within ±0.01mm. Furthermore, a smoothing process is performed after welding. A ceramic-material lower pressure roller 405b cooperates with the fixed roller 405a. A cylinder-driven (adjustable within the range of 1N–900N) downward pressure drives the lower pressure roller 405b to descend, smoothing out the burrs produced after welding.

[0029] By using rollers with different tilt angles and rotation speeds in the third roller group 400, the friction between the narrow foil l and the wide foil m is effectively increased, suppressing the relative displacement caused by differences in size and mechanical properties. This significantly improves the drift problem during welding and ensures the stability of the welding position. Simultaneously, in welding process S200, a servo motor controls the synchronous movement of the foil, and combined with the precise pressure applied by the welding head 403a, the welding deviation is controlled within ±0.01mm, achieving high-precision welding and improving battery safety and consistency. The welding machine base 403b of the welding mechanism 403 is also equipped with a buffer pad and heat dissipation channel, effectively reducing the mechanical stress and heat accumulation generated during welding, protecting the structural integrity of the composite current collector, and extending battery life. Furthermore, the ceramic pressure roller 405b, installed after welding, works in conjunction with the fixed roller 405a to adjust the downward pressure according to process requirements, efficiently removing welding burrs, improving the flatness of the welding surface, and further ensuring the stability and reliability of subsequent battery manufacturing processes. This invention, through the organic combination of the above-mentioned technical means, systematically solves the key technical problems existing in the welding of composite current collectors, such as drift, dimensional instability, and thermal damage, significantly improving welding quality and production efficiency. It is especially suitable for electric vehicles and high-end electronic equipment fields with stringent battery performance requirements.

[0030] Reference Figures 1-2 Specifically, in the tension control process S100, the first unwinding mechanism 100 is sequentially equipped with upper roller 101, upper roller 202, upper roller 303, upper roller 404, upper roller 505, upper roller 606, upper roller 707, upper roller 808, and upper roller 909 along the processing direction of the narrow foil l. Upper roller 101 is used to unwind the narrow foil l; upper roller 202 is a guide roller used to provide an angle for the narrow foil l; upper rollers 303 and 505 provide tension control for the tension lever of the narrow foil l, with a tension control range of 4N-30N; upper rollers 404, 606, 707, 808, and 909 provide tension angle prevention for the narrow foil l. Excessive tension can cause the foil to break. The second unwinding mechanism 200 is equipped with a series of rollers along the processing direction of the wide foil m: roller 1 201, roller 2 202, roller 3 203, roller 4 204, roller 5 205, roller 6 206, roller 7 207, roller 8 208, and roller 9 209. Roller 1 201 is used to unwind the wide foil m. Roller 2 202 is a guide roller used to provide an angle for the wide foil m. Rollers 3 203 and 5 205 provide tension control for the tension lever of the wide foil m, and the tension control range of the wide foil m is 4N-30N. Rollers 4 204, 6 206, 7 207, 8 208, and 9 209 provide a tension angle for the wide foil m to prevent excessive tension from causing the foil to break.

[0031] Narrow foil material l processing direction: The narrow foil material l begins its processing journey from the first unwinding mechanism 100. Throughout the process, multiple rollers sequentially and precisely control the narrow foil material l to ensure its stability and consistency throughout the welding process. First, upper roller 101, as the initial unwinding roller, is responsible for smoothly releasing the narrow foil material l from the roll, ensuring the continuity of subsequent processes. Next, upper roller 2 102, as the guide roller, provides the narrow foil material l with a suitable angle, ensuring that it maintains the correct path and posture when entering the subsequent tension control system. Subsequently, upper roller 3 103, as the first tension lever, is used to initially adjust and maintain the tension of the narrow foil material l, while upper roller 5 105, as the second tension lever, further precisely adjusts the tension of the narrow foil material l. At this stage, the tension of the narrow foil material l is controlled within a specific range (4N to 30N) to ensure that the material... In subsequent operations, no problems will arise due to excessive or insufficient tension. During this process, the upper roller 104 plays a role in smooth transition and coordination. In the following process, the auxiliary guide rollers, such as the upper rollers 106, 107, 108, and 109, not only help guide the narrow foil material l in its forward direction, but also further fine-tune its tension to prevent material breakage due to excessive tension. This ensures that the material is in the optimal state before smoothly entering the third roller group 400. This series of steps work together to ensure that the narrow foil material l reaches the ideal physical state before entering the welding process S200, avoiding any factors that may lead to welding failure.

[0032] Similarly, in the processing direction of the wide foil material m, the wide foil material m undergoes similar processing via the second unwinding mechanism 200 to ensure its stability and consistency throughout the entire processing. First, the lower roller 1 201, acting as the initial unwinding roller, smoothly releases the wide foil material m from the roll, ensuring the continuity of subsequent processes. Next, the lower roller 202, acting as a guide roller, provides the wide foil material m with a suitable angle, ensuring it maintains the correct path and posture when entering the subsequent tension control system. Subsequently, the lower roller 3 203, acting as the first tension lever, initially adjusts and maintains the tension of the wide foil material m, while the lower roller 5 205, acting as the second tension lever, precisely adjusts the tension of the wide foil material m again. At this stage, the tension of the wide foil material m is controlled within a specific range (4N to 30N) to ensure the material... In subsequent operations, no problems will arise due to excessive or insufficient tension. During this process, the lower roller 4 204 plays a role in smooth transition and coordination. In the following process, the auxiliary guide rollers, such as the lower rollers 6 206, 7 207, 8 208, and 9 209, not only help guide the direction of the wide foil material m forward, but also further fine-tune its tension to prevent material breakage due to excessive tension. This ensures that the material is in the optimal state before smoothly entering the third roller group 400. This series of steps work together to ensure that the wide foil material m reaches the ideal physical state before entering the welding process S200, avoiding any factors that may lead to welding failure.

[0033] In the tension control process S100, a correction device is also provided, which includes a photoelectric sensor for detecting the position of the foil edge and a correction execution mechanism located after the upper roller 9 109 and the lower roller 9 209 and before the third roller shaft group 400.

[0034] The web guiding device consists of photoelectric sensors and a web guiding actuator. The photoelectric sensors, typically mounted on both sides of the foil, detect the position of the foil edge by emitting a light beam and receiving the reflected light to determine the exact position of the foil edge. Once the foil deviates from the predetermined path, the sensor immediately detects this change and transmits the signal to the control system. The web guiding actuator, located before the third roller group 400 after the upper roller 9 109 and the lower roller 9 209, is responsible for real-time adjustment of the foil based on the feedback information provided by the photoelectric sensors. This actuator mainly includes a guiding device, a driving device, and a control system. The guiding device typically consists of a set of movable guide wheels or guide plates, capable of fine-tuning according to the instructions of the control system. The driving device generally uses a cylinder or electric motor as a power source, providing the necessary pushing and pulling force to adjust the position of the guiding device. The control system is integrated inside the equipment, responsible for processing the feedback signals from the photoelectric sensors and issuing corresponding instructions to the driving device, thereby realizing the automatic web guiding function and ensuring that the foil remains on the correct track throughout the entire transmission process.

[0035] It should be noted that in the tension control process S100, the operation of the guide device begins with initial state setting. Before production begins, the operator needs to set the ideal foil running path and manually adjust the position of the guide actuator to place it in the reference position. At the same time, the photoelectric sensor is also calibrated to its optimal working state to ensure accurate detection of changes in the foil edge position. After entering the real-time monitoring and feedback stage, the photoelectric sensor continuously monitors the position of the foil edge during production. Once a deviation of the foil is detected (e.g., deviating to the left or right from the preset path), the sensor immediately transmits this information. The signal is converted into an electrical signal and sent to the control system. Then, during the correction execution phase, the control system receives the signal, immediately analyzes the degree and direction of the deviation, and issues instructions to the correction execution mechanism accordingly. Specifically, if the foil shifts to the left, the control system will instruct the drive device to push the guide device to the right, so that the foil returns to the correct path. Conversely, if the foil shifts to the right, the guide device will be pushed to the left to correct the deviation. In this way, the correction execution mechanism can dynamically adjust the position of the foil without stopping the machine, ensuring that it always stays on the correct track, thereby achieving efficient and accurate correction operation.

[0036] The reasons for placing the web guide after the upper roller 9 (109) and lower roller 9 (209) and before the third roller group 400 are as follows: First, at this position, the foil has undergone multiple guidance and tension adjustments, reaching a relatively stable state. Adjusting the web guide at this point minimizes interference in subsequent processes. Second, because the foil tension is relatively balanced at this location, any minor adjustment is quickly reflected in the foil's actual position, making the web guide more precise and effective. Finally, if the web guide is placed too close to the unwinding mechanism or welding process S200, frequent and unnecessary adjustments may occur due to tension fluctuations, affecting overall efficiency. However, after the upper roller 9 (109) and lower roller 9 (209) and before the third roller group 400, the foil's path has stabilized, allowing for more efficient web guide operation. This ensures that the foil remains on the correct track throughout the production process, avoiding quality problems caused by deviation. This setup not only improves the stability and reliability of the entire system but also optimizes production efficiency, ensuring high-quality standards for the final product.

[0037] Among them, the width of the narrow foil l is 5–9 mm, and the tension of the narrow foil l is 3N–10N; the width of the wide foil m is 10–50 mm, and the tension of the wide foil m is 3N–30N; the width of the composite foil electrode n is 55–700 mm, and the unwinding tension of the composite foil electrode n is 20N–120N.

[0038] It should be noted that the width of the narrow foil l ranges from 5 to 9 millimeters (mm). This narrow design helps to improve the energy density and conductivity of the battery. The narrow foil l begins its processing journey from the first unwinding mechanism 100, passing through a series of guide rollers and tension levers to ensure that appropriate tension (3N-10N) is maintained throughout the welding process. This precise tension control prevents the material from breaking or being overstretched during transport.

[0039] The width of the wide foil m ranges from 10 to 50 millimeters (mm), wider than that of the narrow foil l, and is typically used to provide a larger contact area to enhance welding strength and stability. The wide foil m is also unwound via a second unwinding mechanism 200, and through a similar guiding and tension control system, ensures that its tension is maintained within the range of 3N-30N, thereby avoiding problems caused by excessive or insufficient tension.

[0040] The composite foil electrode n, as the third material, has a width of 55–700 mm, and its unwinding tension is precisely controlled within the range of 20 N to 120 N. This wide tension range is designed to accommodate the physical properties and mechanical strength requirements of the composite foil, ensuring its stability during subsequent lamination and welding processes. The composite foil electrode n is unwound via the third unwinding mechanism 300 and enters the third roller group 400 for lamination together with the other two foil materials.

[0041] In the third roller assembly 400, the narrow foil l and the wide foil m are located on the upper and lower surfaces of the composite foil electrode n, respectively, forming a stable three-layer stacked structure. The specific operating steps are as follows: First, after passing through their respective unwinding mechanisms and tension control systems, the narrow foil l and the wide foil m enter the third roller assembly 400. At this stage, the tension of the narrow foil l and the wide foil m has been precisely adjusted to ensure they maintain the correct posture and path when entering the bonding area. Simultaneously, the composite foil electrode n is smoothly released from the third unwinding mechanism 300 and enters the third roller assembly 400 through a set of guide rollers. During this process, the tension of the composite foil electrode n is strictly controlled within the range of 20N to 120N to ensure that it does not deform or shift when bonded with the other two foils. Then, in the third roller assembly 400, the narrow foil l and the wide foil m are respectively guided to the composite foil electrode n... The upper and lower surfaces of the composite foil electrode n are precisely aligned and tightly bonded together by multiple rollers with different tilt angles and rotation speeds. These rollers not only help adjust the angle of the foils but also increase friction through speed differences, preventing any foil from shifting during the bonding process. Finally, after the three-layer stacked structure is formed, it is further fine-tuned by adjusting roller group 402 to ensure a stronger and flatter bond between the foils. Subsequently, the composite structure enters the welding process S200, where welding is completed under the action of welding head 403a and base 403b, forming a multi-layer composite foil. The entire process ensures the precise alignment and stable bonding of the three layers, thereby improving the quality and performance of the final product.

[0042] The third roller group 400 includes, in sequence along the processing direction, an extrusion roller group 401, an adjusting roller group 402, a welding mechanism 403, a first transition roller 404, a smoothing roller group 405, a second transition roller 406, and a take-up roller 407. The extrusion roller group 401 includes an upper extrusion roller 401a and a lower extrusion roller 401b stacked on top of each other, used for stacking and bonding three types of foil: composite foil electrode n, narrow foil l, and wide foil m. The adjusting roller group 402 includes an adjusting roller 402a, an adjusting roller 402b, and an adjusting roller 402c, which have different speed settings to increase the friction between the foils and suppress deviation through speed differences. The welding mechanism 403 includes a welding machine head 403a and a welding machine base 403b, which is used to weld the three types of foil stacked and bonded together to form a multi-layer composite foil. The smoothing roller group 405 includes a fixed roller 405a and a lower pressure roller 405b, used to flatten the burrs generated after welding.

[0043] It should be noted that in the composite current collector welding method, the third roller assembly 400 is a key component for achieving precise bonding and final welding of the narrow foil material l, the wide foil material m, and the composite foil electrode n. The entire third roller assembly 400, along the processing direction, includes, in sequence, the extrusion roller assembly 401, the adjusting roller assembly 402, the welding mechanism 403, the first transition roller 404, the smoothing roller assembly 405, the second transition roller 406, and the take-up roller 407, each part having its specific function and role.

[0044] First, the three foil materials (composite foil electrode n, narrow foil l, and wide foil m) are initially bonded together by stacked extrusion rollers 401. The upper extrusion roller 401a and the lower extrusion roller 401b are located above and below the foil materials, respectively, ensuring close contact and forming a stable three-layer structure. The main purpose of this stage is to bring the three foil materials to an ideal physical state before proceeding to subsequent processes, laying the foundation for precise welding.

[0045] Next, the foil, after initial bonding, enters the adjusting roller group 402. The adjusting roller group 402 consists of multiple rollers with different speed settings. These rollers increase the friction between the foils through speed differences, effectively suppressing foil drift during transport. Specifically: Adjusting roller one 402a is used for initial adjustment of the foil's angle and tension, with its tilt angle set within a specific range to ensure the foil smoothly enters the next stage. Adjusting roller two 402b further fine-tunes the foil's position and increases friction through different speed settings to prevent relative displacement. Adjusting roller three 402c is responsible for final adjustment, ensuring that the three types of foil maintain the correct path and posture before entering the welding mechanism 403. This multi-stage adjustment design not only improves the stability of the foil but also significantly reduces drift problems caused by differences in size and mechanical properties.

[0046] After the adjusting roller group 402 completes the fine adjustment of the foil, the foil enters the welding mechanism 403 area. The welding mechanism 403 includes a welding head 403a and a base 403b. The welding head 403a applies a certain pressure and excites ultrasonic energy to firmly weld the three layers of foil together to form a multi-layer composite foil. During the welding process, the pressure and ultrasonic energy of the welding head 403a are precisely controlled to ensure the stability and consistency of the welding quality. In addition, the welding mechanism 403 is equipped with a buffer pad and heat dissipation channels, which effectively reduces mechanical stress and heat accumulation during the welding process and protects the structural integrity of the composite current collector.

[0047] After welding, the composite foil enters the transition roller 404. The main function of the transition roller 404 is to guide the composite foil smoothly into the next process and provide necessary support to ensure that the foil does not wrinkle or break during transport. The design of the transition roller takes into account the thickness and strength requirements of the foil to ensure a smooth transition to the next processing step.

[0048] To remove burrs generated during the welding process, the composite foil then enters the smoothing roller assembly 405. The smoothing roller assembly 405 consists of a fixed roller 405a and a pressure roller 405b, where the pressure roller 405b is typically made of ceramic, offering good wear resistance and surface smoothness. A cylinder-driven pressing mechanism is installed between the pressure roller 405b and the fixed roller 405a, allowing adjustment of the pressing pressure according to process requirements to ensure efficient removal of burrs generated after welding. This step significantly improves the quality and smoothness of the welded surface, facilitating the smooth progress of subsequent processes.

[0049] After being smoothed, the composite foil enters the second transition roller 406. The function of the second transition roller 406 is similar to that of the first transition roller 404. Its main purpose is to ensure the flatness of the foil while smoothly guiding it to the take-up roller 407, thus ensuring the continuity and stability of the entire production process.

[0050] Finally, the composite foil, after a series of processing steps, enters the take-up roller 407. The take-up roller 407 is responsible for neatly winding the finished composite foil for subsequent storage and transportation. During the winding process, a servo motor drive and a precise tension control algorithm ensure that the wound foil is wrinkle-free and has uniform tension, thereby improving the quality and consistency of the battery electrodes.

[0051] Through the detailed process described above, the third roller assembly 400 not only achieves precise bonding and welding of narrow foil l, wide foil m, and composite foil electrode n, but also effectively solves problems such as drift, dimensional instability, and thermal damage existing in the prior art, significantly improving welding quality and production efficiency. This improvement is particularly important in applications with extremely high battery performance requirements, such as electric vehicles and portable electronic devices.

[0052] Please see Figure 4 Furthermore, the tilt angles of the adjusting rollers 402a, 402b, and 402c relative to the horizontal plane are C1, C2, and C3, respectively, where C1 is 60°–95°, C2 is 90°–120°, and C3 is 120°–170°.

[0053] It should be noted that, under the action of the adjusting roller group 402, the narrow foil l, the composite foil electrode n, and the wide foil m are stacked in order from top to bottom: the narrow foil l is located on the top layer. As the thinnest foil, it needs more support to ensure that it will not shift during transmission; the composite foil electrode n is located in the middle layer, which serves to connect the upper and lower foil layers and ensure the stability and consistency of the entire structure; the wide foil m is located on the bottom layer. Due to its larger width, it needs sufficient support from below to prevent deformation or displacement during transmission. The three foil materials are pressed from top to bottom by adjusting rollers 402a and 402c, and from bottom to top by adjusting roller 402b. This design provides significant advantages: First, the S-shaped path increases the contact area between the foil materials, thereby enhancing the overall structural stability and reducing the risk of misalignment during transport. Second, through multi-level adjustment and pressing at different angles, the three foil materials can be more precisely bonded together, ensuring they reach their optimal state before entering the welding mechanism 403. Furthermore, the adjusting rollers at different angles can optimize the tension distribution based on the physical properties of the foil materials, avoiding material breakage or overstretching due to excessive tension. Finally, through speed differences and increased friction, the adjusting roller group 402 effectively suppresses foil misalignment during transport, ensuring it maintains the correct path and orientation before entering the welding mechanism 403. The S-shaped path design is based on mechanical principles. It forms a complex path through multiple adjusting rollers at different angles, increasing the contact area and friction between the foils. This not only provides better support but also effectively reduces misalignment. It also adapts to foils of different thicknesses and widths, ensuring consistency and stability during transmission. This enhances stability, improves bonding accuracy, optimizes tension distribution, and reduces misalignment, ensuring efficient operation and high-quality output of the entire system.

[0054] The angle C1 of the adjusting roller 402a is set between 60° and 95°, and its main function is to initially guide and align the narrow foil l. This angle range is chosen because the relatively small angle of 60° to 95° provides a gentler entry path, preventing excessive impact on the narrow foil l upon entering the system. From a mechanical perspective, a smaller angle helps reduce bending stress on the material, avoiding wrinkles or breakage caused by sudden changes in direction. This angle also guides the narrow foil l smoothly into the system and gradually adjusts its position. Considering that the narrow foil l is typically thin and easily deformed, a gentler guiding mechanism is needed to ensure its stability. Specific benefits include: an appropriate guiding angle effectively reduces initial deviation of the narrow foil l upon entering the system, preventing material instability due to excessive angle; furthermore, the gentle angle design reduces bending stress on the material, lowering the risk of wrinkles and breakage, thereby ensuring the stability and consistency of the narrow foil l throughout the transport process. This design not only improves production efficiency but also significantly enhances the quality of the final product.

[0055] The angle C2 of the adjusting roller 402b is set between 90° and 120°, and its main function is to stabilize and adjust the position of the wide foil m. This large angle range provides sufficient support to help the wide foil m remain stable throughout the transmission process, preventing it from shifting or sagging. From a mechanical perspective, a larger angle provides stronger support, effectively preventing deformation and shifting of the wide foil m during transmission. This angle range also provides a certain amount of friction, further increasing the adhesion between the foils. Considering that the wide foil m is prone to deformation or shifting during transmission due to its large width, greater support is needed to ensure its stability. Specific benefits include: a larger support angle ensures the wide foil m remains stable throughout the transmission process, preventing shifting or sagging; the larger angle also provides a larger contact area, increasing friction and helping to improve the adhesion accuracy between the three foils (narrow foil l, composite foil electrode n, and wide foil m), thus ensuring an ideal adhesion state before entering the welding mechanism 403, laying a solid foundation for subsequent precise welding. This design not only enhances the stability of the overall system, but also significantly improves the quality and consistency of foil bonding.

[0056] The angle C3 of the adjusting roller 402c is set to a range of 120° to 170°. Its function is to ultimately adjust and compress the three foils (narrow foil l, composite foil electrode n, and wide foil m) to form an S-shaped path. This angle range of 120° to 170° is chosen because it represents the largest angle range, providing the strongest compressive force and ensuring that the three foils reach an ideal bonding state before entering the welding mechanism 403. From a mechanical perspective, a larger angle provides maximum support and friction, effectively bonding the three foils tightly together. The S-shaped path formed by this compression further increases the friction between the foils, reducing misalignment. Considering the material properties, it is necessary to ensure a tight bond between the three foils in the final stage to meet the requirements of the subsequent welding process S200. A larger angle provides sufficient pressure to ensure the bonding degree between the foils. Specific benefits include optimized tension distribution. By setting different angles, the tension distribution can be optimized according to the physical properties of the foil, avoiding material breakage or overstretching caused by excessive tension. Simultaneously, the S-shaped path increases the contact area and friction between the foils, significantly reducing misalignment and ensuring they maintain the correct path and orientation before entering the welding mechanism 403. This design not only improves the bonding accuracy and stability of the foils but also significantly reduces misalignment, enhancing the quality and efficiency of the entire welding process.

[0057] Through the detailed analysis of mechanical principles and material properties described above, it can be seen that these specific angle settings not only improve the bonding accuracy and stability of the foils but also significantly reduce misalignment, thereby enhancing the quality and efficiency of the entire welding process. Specifically, angles of 60° to 95° provide a smooth guiding path for the narrow foil l, reducing the risk of wrinkles and breakage, and ensuring a smooth transition and gradual position adjustment during its initial entry into the system; angles of 90° to 120° provide sufficient support for the wide foil m, ensuring its stability during transmission and preventing deformation or misalignment due to its greater width; angles of 120° to 170° form an S-shaped path through strong extrusion, ensuring a tight bond between the three foils (narrow foil l, composite foil electrode n, and wide foil m), reducing misalignment, and optimizing tension distribution to avoid material breakage or overstretching caused by excessive tension.

[0058] Please see Figure 3The linear velocities of regulating roller 1 (402a), regulating roller 2 (402b), and regulating roller 3 (402c) satisfy the following relationships: the linear velocity V2 of regulating roller 2 (402b) > the linear velocity V3 of regulating roller 3 (402c); the linear velocity V1 of regulating roller 1 (402a) < the linear velocity V2 of regulating roller 2 (402b); the linear velocity V1 of regulating roller 1 (402a) ≤ the linear velocity V3 of regulating roller 3 (402c); and V1, V2, and V3 are all within the range of 1-3 m / min; the difference between the linear velocities of V2 and V3 is within the range of 0.05-0.3 m / min; and the difference between the linear velocities of V2 and V1 is within the range of 0.05-0.3 m / min.

[0059] By establishing a precise linear velocity difference, a dynamic tension field is formed in the foil conveying path. Adjusting roller 2 (402b) is set to the peak point of velocity V2 (linear velocity 1-3 m / min). Its velocity V2 is higher than both the upstream adjusting roller 1 (402a) and the downstream adjusting roller 3 (402c) (V3), and the velocity difference is strictly controlled within the range of 0.05-0.3 m / min. This design primarily follows the principle of plastic deformation of materials. When the foil enters the high-speed roller (adjusting roller 2 (402b) from the low-speed roller (adjusting roller 1 (402a)), tensile stress is generated due to the sudden increase in velocity. The foil material between regulating roller 1 (402a) and regulating roller 2 (402b) is kept in a controllable stretching state. However, when the foil material enters the low-speed regulating roller 3 (402c) from the high-speed regulating roller 2 (402b), the sudden decrease in speed creates reverse compressive stress, resulting in a tensioning effect between the two rollers. The upper and lower limits of the speed difference, 0.05 m / min and 0.3 m / min respectively, are derived from critical fracture strain calculations: below 0.05 m / min, the stress is insufficient to suppress drift; above 0.3 m / min, the yield strength of the aluminum foil (δ=2%) is exceeded, leading to fracture. Crucially, the speed relationship between regulating roller 1 (402a) and regulating roller 3 (402c) (V1≤V3) is crucial. This constraint ensures speed compatibility between wide and narrow foil materials at the confluence point, preventing interlayer shear slippage caused by flow rate mismatch. The measured data show that when the speed difference is 0.15m / min, the foil drift decreases sharply from the reference value of ±3mm to ±0.02mm. Essentially, the speed gradient field converts the transverse vibration energy transmitted by the welding head 403a into the longitudinal strain energy of the foil.

[0060] Please see Figure 5 A first tension value T1 is formed on the foil between the first adjusting roller 402a and the second adjusting roller 402b; a second tension value T2 is formed on the foil between the second adjusting roller 402b and the third adjusting roller 402c; the first tension value T1 is less than the second tension value T2.

[0061] In the first tension zone between the first adjusting roller 402a and the second adjusting roller 402b, the foil material bears the first tension value T1 with a lower tension value. In this state, the foil material generates microscopic slip, and the input energy of the welding head 403a is consumed through Coulomb friction. In the second tension zone between the second adjusting roller 402b and the third adjusting roller 402c, the foil material bears the second tension value T2 with a higher tension value. At this time, the Young's modulus of the foil material increases by about 40% (according to Hooke's law E∝T), significantly enhancing the bending stiffness to suppress vibration deformation. The hierarchical relationship of T1<T2 is not arbitrarily set: if T1≥T2, the extension effect in the low-speed area disappears, and the vibration transmission rate of the foil material increases; if T2 is too low, the tensioning effect in the high-speed area fails. This tension zoning is achieved through the coordinated adjustment of the tension swing rod of the narrow foil l and the tension swing rod of the wide foil m. Its mechanical essence is to construct a "relaxed - tight" damping attenuation channel. The front low-tension area absorbs 60% of the vibration energy, and the rear high-tension area blocks the transmission of the remaining energy.

[0062] Among them, the welding mechanism 403 includes a welding head 403a and a base 403b. The welding pressure applied by the welding head 403a is 50N–200N. The base 403b is provided with a buffer pad and a heat dissipation channel for reducing welding vibration and heat accumulation.

[0063] In the composite current collector welding process, the welding mechanism 403 is a key component to ensure the tight combination of the three layers of materials, namely the narrow foil l, the wide foil m, and the composite foil electrode n. It mainly includes two parts: the welding head 403a and the base 403b. As the part that directly applies the welding pressure and excites the welding energy, the main function of the welding head 403a is to apply appropriate pressure to the three superimposed foils and firmly connect them through welding methods such as ultrasonic or resistance welding. The pressure range applied by the welding head 403a is 50N to 200N. The selection of this range is based on various factors, including the thickness of the foil material, material hardness, and required welding strength. Appropriate welding pressure can ensure the tight contact between the foils, thereby improving the welding quality. At the same time, the welding head 403a is also responsible for transmitting the energy forms required for welding (such as ultrasonic waves, lasers, or resistance heat). These energy forms are precisely controlled by the welding head 403a to ensure the best matching of temperature and time during the welding process, thereby obtaining an ideal welding effect.

[0064] As a crucial component supporting the foil during the welding process, the base 403b plays an equally important role. To improve welding quality and protect the foil structure, the base 403b is specially designed with a buffer pad and heat dissipation channels. The buffer pad is usually made of elastic materials, such as rubber or polyurethane, which can effectively absorb the vibration generated during welding. This design not only helps to reduce the impact of mechanical stress on the foil, but also prevents wrinkles or breakage that may occur during welding. The heat dissipation channels are designed to quickly remove the heat generated during welding, avoiding deformation or damage to the foil due to overheating. Good heat dissipation performance is crucial for maintaining a stable temperature in the welding area.

[0065] The coordinated operation of the welding head 403a and the base 403b is key to achieving high-quality welding. The specific operation process is as follows: First, the three-layer foil material, after being processed in the previous steps, is fed into the welding area and initially aligned between the welding head 403a and the base 403b. Then, the welding head 403a applies downward pressure according to a preset pressure value, making the foil material adhere tightly to the base 403b with a buffer pad. Next, the welding head 403a activates the welding energy source (such as an ultrasonic generator or resistance heating element), transferring energy to the surface of the foil material, causing metal atoms to diffuse into each other and form a strong weld point. After welding, the heat dissipation channel quickly removes excess heat from the welding area, preventing deformation or other adverse effects caused by overheating. Finally, the composite foil material, after the above steps, is smoothly fed out of the welding mechanism 403 and enters the subsequent winding process. This precisely designed welding mechanism 403 not only ensures a strong bond between the three foil layers, but also effectively reduces potential problems during the welding process, such as misalignment, wrinkles, breakage, and overheating. This results in higher reliability and safety for the final product in applications with extremely high battery performance requirements, such as electric vehicles and portable electronic devices.

[0066] Among them, the pressing roller 405b in the smoothing roller group 405 is made of ceramic material, and a cylinder-driven pressing mechanism is provided between it and the fixed roller 405a. The pressing force of this mechanism can be adjusted in the range of 1N–900N.

[0067] In the composite current collector welding process, the smoothing roller assembly 405 is a key component to ensure that the foil surface is flat and burr-free after welding. This assembly consists of a fixed roller 405a and a pressure roller 405b, wherein the pressure roller 405b is made of ceramic material and is equipped with a cylinder-driven pressure mechanism that can adjust the pressure as needed.

[0068] It should be noted that the material selection for the lower pressure roller 405b is as follows: The lower pressure roller 405b is made of ceramic, primarily because ceramic possesses excellent wear resistance and surface smoothness. These material properties ensure that the lower pressure roller 405b is not easily worn during long-term operation, maintaining a high level of surface flatness and effectively reducing damage to the foil surface. Furthermore, ceramic material also exhibits good thermal and chemical stability, maintaining its performance unchanged under high-temperature or corrosive environments, which is particularly important for processing certain special foil materials.

[0069] Working principle of the pressing mechanism: The pressing mechanism is driven by a cylinder, which can precisely control the pressure applied to the foil by the pressing roller 405b. This mechanism allows operators to flexibly adjust the pressing pressure within a certain range according to actual production needs. Specifically: Adjustable range: The pressing pressure can be adjusted between 1N and 900N. This wide adjustment range can adapt to foils of different thicknesses and hardnesses, ensuring that each material achieves the best smoothing effect. Precision control: The cylinder-driven method not only achieves rapid response but also provides stable pressing pressure, avoiding unevenness on the foil surface caused by pressure fluctuations.

[0070] In actual production, the operation procedure of the smoothing roller assembly 405 is as follows: Initial settings: Based on the specific parameters of the foil to be processed (such as thickness, material, etc.), pre-set an appropriate downward pressure. Generally, thinner and softer foils require less downward pressure to prevent excessive compression and deformation; while thicker and harder foils require greater downward pressure to ensure a completely flat surface.

[0071] Smoothing Operation: After welding, the foil enters the smoothing roller group 405 area, first contacting the fixed roller 405a, which provides a stable support surface for the foil. Subsequently, the lower pressure roller 405b, driven by a cylinder, applies a preset pressure to the foil, smoothing out burrs or other surface defects generated during the welding process. Because the lower pressure roller 405b is made of ceramic, its high hardness and smooth surface further enhance the smoothing effect, ensuring the surface quality of the final product.

[0072] Dynamic adjustment: If minor imperfections or unevenness are found on the foil surface during the entire processing, the smoothing effect can be optimized by adjusting the cylinder pressure in real time. This dynamic adjustment mechanism ensures the continuous output of high-quality products even on high-speed production lines.

[0073] Through the above design, the smoothing roller assembly 405 not only effectively removes burrs from the surface of the welded foil but also significantly improves the overall surface quality. The ceramic-material pressure roller 405b, combined with a cylinder-driven adjustable pressure mechanism, provides excellent wear resistance, surface smoothness, and flexible pressure adjustment capabilities. These features collectively ensure efficient and precise smoothing operations under various complex working conditions, thus meeting the demands of applications with extremely high battery performance requirements, such as electric vehicles and portable electronic devices. This sophisticated design not only improves product quality but also enhances the overall efficiency and reliability of the production line.

[0074] Please see Figure 1-2 A composite current collector welding device (corresponding to the implementation device of the above method).

[0075] This device is used to continuously unwind, precisely bond, and weld narrow foil l, wide foil m, and composite foil electrode n into a multilayer composite current collector in a single operation. Its structure and function closely relate to the tension control step S100 and welding step S200 in the aforementioned method, and are briefly described below: First unwinding mechanism 100: Upper roller 1 to upper roller 9 109 are arranged sequentially along the traveling direction of narrow foil l, wherein tension swing rods (upper roller 3 103 and upper roller 5 105, with tension of 4–30N).

[0076] The second unwinding mechanism 200: Lower rollers 1 to 9 are arranged sequentially along the travel direction of the wide foil m, and their structure and parameters are the same as those of the first unwinding mechanism 100.

[0077] The correction device is located after the upper roller 9 109 and the lower roller 9 209. It uses a photoelectric sensor to detect the edge in real time and the correction actuator finely adjusts the position of the foil to ensure that there is no deviation before entering the third roller group 400.

[0078] Third unwinding mechanism 300: provides composite foil electrode n with tension 20–120N.

[0079] The third roller group 400 is arranged sequentially along the processing flow direction: the extrusion roller group 401: the upper extrusion roller 401a and the lower extrusion roller 401b initially press the three foil materials into a three-layer laminate.

[0080] Adjusting roller group 402: Adjusting roller 402a (C1 is 60°–95°, linear velocity V1); Adjusting roller 2 402b (C2 is 90°–120°, linear velocity V2, V2>V1, V2>V3); Adjusting roller 3 402c (C3 is 120°–170°, linear velocity V3, V1≤V3); The three rollers have a speed difference of 0.05–0.3 m / min, forming an S-shaped path, which increases friction and suppresses drift.

[0081] Welding mechanism 403: Welding head 403a provides 50–200N pressure and completes the welding; base 403b has built-in buffer pads and heat dissipation channels to reduce vibration and heat accumulation, and the welding deviation is ≤±0.01mm.

[0082] Transition roller 404: smoothly guides the foil after welding.

[0083] Smoothing roller assembly 405: Ceramic lower pressure roller 405b works in conjunction with fixed roller 405a via a cylinder (1–900N adjustable) to smooth out burrs.

[0084] Transition roller 406 and take-up roller 407: The finished composite current collector is wound up under constant tension.

[0085] Through the above modular design, this device can achieve unwinding, tension control, deviation correction, bonding, welding, deburring and rewinding in one go.

[0086] Finally, it should be noted that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways as long as they do not depart from the scope of the present invention.

Claims

1. A composite current collector welding method, comprising: a first unwinding mechanism (100) for unwinding a narrow foil (l), a second unwinding mechanism (200) for unwinding a wide foil (m), and a welding mechanism (403) disposed after the composite foil electrode (n), the narrow foil (l), and the wide foil (m) are bonded together, characterized in that, include: In the tension control process (S100), the tension of the narrow foil (l) released from the first unwinding mechanism (100) and the wide foil (m) released from the second unwinding mechanism (200) is controlled and guided to the third roller group (400) to bond with the composite foil electrode (n) released from the third unwinding mechanism (300); The welding process (S200) involves welding the narrow foil (l) and the wide foil (m) after they have been bonded together by the third roller group (400), and controlling the deviation range of the narrow foil (l) and the wide foil (m) during welding. The third roller group (400) includes, in sequence along the processing direction, an extrusion roller group (401), an adjusting roller group (402), a welding mechanism (403), a first transition roller (404), a smoothing roller group (405), a second transition roller (406), and a take-up roller (407). The extrusion roller group (401) includes an upper extrusion roller shaft (401a) and a lower extrusion roller shaft (401b) stacked on top of each other. The adjusting roller group (402) includes adjusting roller one (402a), adjusting roller two (402b) and adjusting roller three (402c) in sequence along the processing direction; The tilt angles of the first adjusting roller (402a), the second adjusting roller (402b), and the third adjusting roller (402c) relative to the horizontal plane are C1, C2, and C3, respectively, where C1 is 60°–95°, C2 is 90°–120°, and C3 is 120°–170°. The linear velocities of the regulating roller one (402a), regulating roller two (402b), and regulating roller three (402c) satisfy the following relationship: The linear velocity V2 of regulating roller 2 (402b) is greater than the linear velocity V3 of regulating roller 3 (402c); The linear velocity V1 of regulating roller one (402a) is less than the linear velocity V2 of regulating roller two (402b); The linear velocity V1 of adjusting roller one (402a) is less than or equal to the linear velocity V3 of adjusting roller three (402c); Furthermore, V1, V2, and V3 are all within the range of 1-3 m / min; The difference between V2 and V3 is in the range of 0.05-0.3 m / min; The difference between V2 and V1 is in the range of 0.05-0.3 m / min; A first tension value T1 is formed on the foil between the first adjusting roller (402a) and the second adjusting roller (402b); A second tension value T2 is formed on the foil between the second adjusting roller (402b) and the third adjusting roller (402c); The first tension value T1 is less than the second tension value T2.

2. The composite current collector welding method according to claim 1, characterized in that: The welding mechanism (403) includes a welding head (403a) and a base (403b) arranged opposite to each other. The smoothing roller assembly (405) includes a fixed roller (405a) and a pressure roller (405b) arranged opposite to each other.

3. The composite current collector welding method according to claim 2, characterized in that: The welding head (403a) applies a welding pressure of 50N–200N, and the base (403b) is provided with a buffer pad and a heat dissipation channel.

4. The composite current collector welding method according to claim 3, characterized in that: The pressing roller (405b) in the smoothing roller group (405) is made of ceramic material. A cylinder-driven pressing mechanism is provided between the pressing roller (405b) and the fixed roller (405a). The pressing force of the pressing mechanism can be adjusted in the range of 1N–900N.

5. The composite current collector welding method according to claim 4, characterized in that: In the tension control process (S100), the first unwinding mechanism (100) is provided with upper roller one (101), upper roller two (102), upper roller three (103), upper roller four (104), upper roller five (105), upper roller six (106), upper roller seven (107), upper roller eight (108), and upper roller nine (109) in sequence along the processing direction of the narrow foil (l). The second unwinding mechanism (200) is provided with lower roller 1 (201), lower roller 2 (202), lower roller 3 (203), lower roller 4 (204), lower roller 5 (205), lower roller 6 (206), lower roller 7 (207), lower roller 8 (208), and lower roller 9 (209) in sequence along the processing direction of the wide foil material (m).

6. The composite current collector welding method according to claim 5, characterized in that: The narrow foil (l) has a width of 5–9 mm and a tension of 3 N–10 N. The width of the wide foil (m) is 10–50 mm, and the tension of the wide foil (m) is 3N–30N; The width of the composite foil electrode (n) is 55–700 mm, and the unwinding tension of the composite foil electrode is 20 N–120 N.

7. A composite current collector welding device, characterized in that, The composite current collector welding device is a composite current collector welding device for implementing the method of any one of claims 1-6.

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