Battery piece grid line transfer printing device and method

Abstract

The invention relates to a cell grid line transfer printing device and method. The device comprises an unwinding assembly and a winding assembly and is used for conveying the patterned transfer printing film. The visual inspection assembly is used for acquiring position information of the film and the battery piece; a carrying platform of the pasting bearing platform is used for bearing the battery piece and is driven by a first moving part to realize horizontal movement and movement perpendicular to a film surface so as to finish alignment and pasting; and the pressing roller assembly comprises a heating roller, a first temperature control part used for accurately controlling the temperature and a pressure adjusting part used for adjusting the pressure so as to complete hot pressing transfer printing. The device can also comprise a movable heating plate for preheating the film, a carrying table temperature control part for preheating the battery piece, and a vacuum adsorption and liftable carrying table for fixing the battery piece. The corresponding method comprises the steps of battery piece feeding and alignment, vertical attachment, heating and rolling and base film removal, and can comprise the step of preliminary pressing, and the alignment precision, the hot-pressing uniformity and the production efficiency of transfer printing can be improved.

Description

Battery cell grid line transfer device and method Technical Field

[0001] This application relates to the field of photovoltaic cell manufacturing technology, and in particular to a cell grid line transfer device and method. Background Technology

[0002] In the field of crystalline silicon photovoltaic cell manufacturing, the precise fabrication of grid line patterns is one of the core aspects of improving cell photoelectric conversion efficiency. With technological advancements, grid line designs are continuously evolving towards finer lines and higher aspect ratios to reduce shading losses and series resistance. While traditional screen printing technology is mature and widely used, its physical principles limit its ability to print extremely fine lines, leading to bottlenecks such as screen lifespan, ink clogging, and line consistency, thus restricting further improvements in cell efficiency.

[0003] To overcome this limitation, a pre-patterned transfer technology has gained attention. This approach involves creating grooves with precise microstructures on a flexible carrier film and filling them with conductive paste to form patterned "grid negatives," which are then physically transferred to the battery surface. This method can produce grid lines with bottom widths as low as a few micrometers, providing a potential path to achieving ultra-fine, highly conductive grid lines. However, transforming the laboratory transfer concept into a continuous and stable production system suitable for industrial-scale, large-size silicon wafers still faces a series of pressing technical challenges. First, there is the requirement for alignment accuracy at the nanometer to micrometer level. The transferred pattern must maintain extremely high positional and angular alignment with the crystal orientation, edges, and existing electrodes (such as the main grid) of the silicon wafer. The dimensional tolerances of the silicon wafer itself and the minute deformations of the carrier film during transport both place demands on the dynamic alignment system's conventional mechanical positioning capabilities.

[0004] Uniform control of thermodynamic parameters during the transfer process is crucial to ensuring yield. Transfer requires pressure to ensure reliable contact and adhesion between the slurry and the silicon wafer surface within a specific temperature window. If the temperature or pressure field of the roller pressing mechanism is unevenly distributed along the length, it will lead to differences in the curing degree and adhesion of the transfer slurry, causing localized false printing or uneven grid line resistance, and even increasing the risk of silicon wafer fragmentation due to stress concentration.

[0005] The realization of high-precision transfer printing relies on the coordinated operation of multiple subsystems, including vision alignment, precision motion, hot pressing control, tension management, and peeling. Existing solutions often focus on individual process steps, lacking deep system integration and coordinated control. This results in long equipment cycle times, complex process debugging, and insufficient adaptability when switching between different products, making it difficult to meet the comprehensive requirements of the photovoltaic manufacturing industry for efficiency, cost, and stability.

[0006] Furthermore, flexible films operating in a roll-to-roll manner require stable tension throughout the entire process. Tension fluctuations can cause wrinkling, stretching, or lateral misalignment of the film, directly damaging the pre-formed precision patterns. Additionally, the carrier film must be peeled from the silicon wafer surface in a controlled manner after transfer. Improperly controlled peeling dynamics can cause shearing or tensile damage to the not yet firmly attached micro-grid lines. Therefore, there is a need to develop an automated transfer device that integrates high-precision dynamic visual alignment, uniform and controllable hot-press transfer, and intelligent collaborative operation. Summary of the Invention

[0007] This application provides a solar cell grid line transfer device and method. Its core objective is to ensure alignment, thermo-pressing uniformity, and continuous production stability during the high-precision pattern transfer process from a carrier film to a large-size brittle silicon wafer. It aims to achieve micron-level alignment accuracy and uniform thermodynamic condition control in a dynamic production environment, thereby improving transfer yield and grid line electrical performance. This objective is achieved through the following technical solution: The solar cell grid line transfer device includes an unwinding assembly, a pressing roller assembly, a winding assembly, a vision inspection assembly, and a bonding support platform. The patterned transfer film is conveyed from the unwinding assembly to the winding assembly in a roll-to-roll manner. The pressing roller assembly is positioned on the conveying path. The bonding support platform includes a platform for carrying the solar cell and a first moving component. The first moving component drives the platform to move to a position on the conveying path and can move perpendicularly to the surface of the patterned transfer film. The pressing roller assembly includes a heating roller and a first temperature control component. The vision inspection assembly is used to detect the position of the patterned transfer film and the platform.

[0008] In one embodiment, a heating plate is also included, which is disposed on the patterned transfer film transport path. The heating plate includes a second moving component that drives the heating plate to move a position.

[0009] In one embodiment, the bonding support platform includes a second temperature control component for controlling the platform temperature.

[0010] In one embodiment, the stage further includes adsorption pores.

[0011] In one embodiment, a cutting component is also included.

[0012] In one embodiment, a film-tearing and film-collecting assembly is also included.

[0013] In one embodiment, the pressing roller assembly includes a pressure adjustment component.

[0014] In one embodiment, the bonding support platform further includes a flipping component.

[0015] In addition, this application also provides a method for transferring grid lines on a solar cell, which uses the aforementioned solar cell grid line transfer device and includes the following steps: placing the solar cell on a stage, moving the stage under the transport path of the patterned transfer film; aligning the grid line pattern on the patterned transfer film with the corresponding position on the solar cell; moving the stage vertically toward the surface of the patterned transfer film, so that the patterned transfer film adheres to the surface of the solar cell; passing the solar cell with the patterned transfer film adhered to it through a pressing roller assembly for heating and pressing; removing the base film of the patterned transfer film from the surface of the solar cell, leaving the grid line pattern on the surface of the solar cell.

[0016] In one embodiment, the process further includes using a heating plate and a stage to perform preliminary pressing during the bonding step of the patterned transfer film and the battery cell.

[0017] Compared with existing technologies, this application has the following advantages: In terms of transfer alignment accuracy, by employing a combination of a vision inspection component and a bonding support platform with multi-axis motion capabilities, micron-level precise positioning in dynamic environments is achieved. Based on the real-time position information of the patterned transfer film and the solar cell supported on the platform obtained by the vision system, through calculation and motion compensation, alignment deviations caused by silicon wafer dimensional tolerances and film material transport deformation can be overcome, ensuring precise alignment between the grid pattern and the preset position of the solar cell.

[0018] Regarding the control of hot-press uniformity during the transfer process, a collaborative thermal management system is constructed by setting up a pressing roller assembly including a heating roller and a first temperature control component, combined with an independently temperature-controlled platform and a movable heating plate. This ensures that the transfer interface is in a controlled and uniform temperature field before, during, and after pressing. In particular, precise temperature control of the heating roller (e.g., using PID algorithms and embedded multi-point temperature measurement) maintains the axial temperature difference of its working surface at a low level (e.g., within ±2℃). Simultaneously, precise control of the roller pressure line pressure by the pressure adjustment component ensures uniform distribution of transfer pressure across the width of the silicon wafer. This refined and uniform control of hot-press parameters contributes to the consistency of slurry leveling, interface contact, and curing processes, thereby improving the adhesion strength and electrical performance uniformity of the grid lines and reducing the risk of incomplete printing or fragmentation due to insufficient local hot pressing or overload.

[0019] Regarding the stability and efficiency of continuous production, the roll-to-roll unwinding and rewinding assembly design enables continuous or step-by-step supply and recycling of patterned transfer film. The lamination carrier platform is driven by the first moving component to move the platform horizontally and vertically, achieving rapid loading, alignment, lamination, and removal of solar cells. Its modular operation is coordinated with the film conveying cycle. In addition, optional cutting and film-tearing / rewinding assemblies can adapt to different process paths, enabling automatic removal and processing of the base film. Attached Figure Description

[0020] Figure 1 is a schematic diagram of the structure of a battery cell grid line transfer device in one embodiment of this application; Figure 2 is a schematic flowchart of a battery cell grid line transfer method in one embodiment of this application; Figure 3 is a schematic flowchart of a battery cell grid line transfer method in one embodiment of this application; Figure 4 is a schematic diagram of the structure of a battery cell grid line transfer device in another embodiment of this application.

[0021] Explanation of reference numerals in the attached drawings: 110, unwinding assembly; 120, pressing roller assembly; 130, winding assembly; 140, vision inspection assembly; 150, coating support platform; 160, film tearing and winding assembly; 170, heating plate; 180, cutting assembly; 210, patterned transfer film; 220, battery cell; 230, grid pattern. Detailed Implementation

[0022] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not the entire structure. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0023] The terms “comprising” and “having”, and any variations thereof, used in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0024] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0025] To address the technical challenges encountered in existing technologies when transferring pre-patterned precision grid lines onto large-size, brittle silicon wafers, such as insufficient alignment accuracy, difficulty in controlling the uniformity of hot-pressing parameters (temperature and pressure), poor stability in roll-to-roll continuous production, and difficulties in coordinating multiple process modules, this application provides an integrated and automated solar cell grid line transfer device and method. The technical solution of this application will be described in detail below with reference to the accompanying drawings and specific embodiments. Dynamic high-precision alignment is achieved through the collaboration of a vision inspection component and a multi-axis precision motion platform; uniformity and controllability of hot-pressing parameters at the transfer interface are achieved by constructing a multi-level thermal management system including an independently temperature-controlled stage, a movable preheating component, and heated pressing rollers; and stable and efficient continuous production is ensured through modular roll material transport, tension control, and peeling mechanisms. Please refer to Figure 1, which shows a preferred embodiment of the battery cell grid line transfer device of this application. Figure 1 includes a side view and a top view. The battery cell grid line transfer device includes an unwinding assembly 110, a pressing roller assembly 120, a winding assembly 130, a vision inspection assembly 140, and a bonding support platform 150. The patterned transfer film 210 is conveyed from the unwinding assembly 110 to the winding assembly 130 in a roll-to-roll manner. The pressing roller assembly 120 is disposed on the conveying path. The bonding support platform 150 includes a platform for carrying the battery cell 220 and a first moving component. The first moving component drives the platform to move to a position on the conveying path and can move perpendicularly relative to the surface of the patterned transfer film 210. The pressing roller assembly 120 includes a heating roller and a first temperature control component. The vision inspection assembly 140 is used to detect the position of the patterned transfer film 210 and the platform.

[0026] The unwinding assembly 110 and the rewinding assembly 130 work together to form a roll-to-roll transport system, realizing the automated supply and recovery of the flexible film material (i.e., patterned transfer film 210) carrying the pre-formed grid pattern 230. The pressing roller assembly 120 is set on this transport path, and the hot pressing station for transfer is integrated into the continuous production line, avoiding the frequent material handling interruptions in traditional single-piece processing. The vision inspection assembly 140 is used to acquire the alignment marks on the patterned transfer film 210 and the position information of the battery cell 220 carried on the platform, and uses image processing algorithms to quantify the spatial deviation between the film pattern coordinate system and the battery cell 220 coordinate system in real time.

[0027] The mounting platform 150 is the actuator connecting visual alignment and physical bonding. The platform is used to support and fix the brittle solar cell 220, and its surface is typically equipped with a vacuum adsorption hole array or electrostatic adsorption device to ensure that the solar cell 220 does not slip during movement and pressing. A first moving component drives the platform to achieve at least two degrees of freedom of movement: one is horizontal movement, allowing it to move precisely to the preset bonding position below the patterned transfer film 210; the other is vertical movement, enabling the solar cell 220 to actively approach and contact the stationary or low-speed-moving transfer film at a controllable speed and posture, achieving initial bonding. The platform itself can also integrate a temperature control component (a second temperature control component) to preheat the solar cell 220, reducing thermal shock upon contact with the hot film and promoting slurry interface flow.

[0028] In the pressing roller assembly 120, the heating roller applies pressure and heat to the pre-bonded "film-wafer" composite during the transfer process. The first temperature control component is used to precisely control the surface working temperature of the heating roller, which typically includes a heating element embedded in the roller body, a thermocouple, and an external PID temperature controller. The design of the heating roller must ensure the uniformity of its surface temperature over the effective contact length. A uniform temperature field helps ensure that all grid lines on the entire cell undergo a nearly uniform thermal history, thereby obtaining uniform electrical and mechanical properties. The roller pressure is usually controlled by a pneumatic or servo motor driven mechanism, which works in conjunction with the temperature to complete the reliable transfer and curing of the slurry from the film groove to the silicon wafer surface.

[0029] To further optimize the thermal conditions of the transfer interface during the initial bonding stage, the device of this application also includes a heating plate 170 disposed on the transport path of the patterned transfer film 210. Before or simultaneously with the vertical bonding of the solar cell stage, the localized area of ​​the patterned transfer film 210 moving above the bonding station is preheated. The heating plate 170 integrates a second moving component, giving it the ability to adjust its position. The second moving component can be a linear module, a cylinder, or a servo electric cylinder, etc., driving mechanism. This allows for dynamic matching and synchronization between the working position of the heating plate 170 and the bonding station. Specifically, during the non-coating stage, the heating plate 170 can be moved out of the film material's transmission path to avoid unnecessary prolonged heat radiation or physical interference to the film material. When the system enters the coating cycle, the second moving component drives the heating plate 170 to move precisely to the position directly above or near the area of ​​the battery cell to be coated on the back of the film material. This ensures that the preheating energy can be applied efficiently and centrally to the specific film segment where the transfer is about to occur, reducing heat loss and improving preheating efficiency and temperature control response speed.

[0030] Before the main rolling of the pressing rollers, the carrier film is preheated by the heating plate 170. This raises the temperature of the slurry in the film from room temperature to a temperature range closer to its softening point or optimal flow dynamics, reducing the viscosity of the slurry at the initial contact moment and promoting faster wetting and microscopic contact with the surface of the solar cell 220. Simultaneously, preheating the film also reduces the temperature difference between it and the preheated solar cell 220, thereby reducing the risk of microcracks in the silicon wafer due to thermal stress. The combination of preheating and subsequent main heating by the heating rollers constitutes a gradual, gradient-controllable thermal field application process, which facilitates the smooth transition of the slurry from a "solid-viscoelastic-flow dynamic-re-curing" state.

[0031] To create a balanced and controllable thermal environment for the transfer interface, the mounting platform 150 of this application further integrates a second temperature control component specifically for temperature control of the stage supporting the solar cell 220. The second temperature control component may include heating elements such as resistance heating wires, hot runners, or liquid circulation pipes embedded within the stage, and a temperature sensor coupled to them. A closed-loop control circuit is formed through an independent temperature controller (which may be a PID controller), thereby maintaining the stage surface temperature within a set process range. The stage surface is typically also specially treated; for example, vacuum adsorption holes are provided on the contact surface with the solar cell 220, and it is made of a material with good thermal conductivity, such as anodized aluminum or metal with a Teflon coating, to ensure uniform heat conduction and prevent damage to the back of the solar cell 220.

[0032] A second temperature control component actively controls the temperature of the stage, preheating the bottom of the solar cell 220. This reduces the thermal shock experienced by the brittle silicon wafer upon contact with the preheated transfer film, increasing the initial temperature of the solar cell 220. This helps to ensure that the silicon wafer surface in contact with the paste is at a more favorable temperature for interfacial bonding during the subsequent rolling stage. By coordinating the temperature of the stage (and solar cell 220) with the temperature of the transfer film through the second temperature control component, the entire transfer interface (paste-film-silicon wafer) can achieve a more uniform thermal equilibrium state closer to the optimal process window before lamination. Using a bidirectional preheating mode, compared to a single-sided heating scheme, provides more consistent and controllable initial conditions for the flow, venting, and curing of the paste during the subsequent lamination process, thereby helping to improve the adhesion uniformity and batch stability of the grid line transfer.

[0033] To further optimize the positioning stability and stress state of the battery cell 220 during the bonding and pressing process, the stage in this application is further provided with adsorption pores. One or more micro-pores connected to a vacuum system are formed on the working surface of the stage used to support the battery cell 220. In a specific embodiment, the stage is constructed to be height-adjustable, and its working surface can form grooves or adaptive support structures that match the shape or size of the battery cell 220 to be processed, according to process requirements. Vacuum adsorption is used to extract air between the adsorption pores and the back of the battery cell 220 using a vacuum pump. Atmospheric pressure is used to press the battery cell 220 tightly and flatly onto the stage surface. Without introducing mechanical clamping stress, this effectively overcomes the displacement of the battery cell 220 caused by its own warping or external forces (such as tension during film peeling), providing a stable reference for high-precision visual alignment and subsequent pressing processes. When the platform surface rises to form a shallow groove, the boundary of the groove can provide preliminary mechanical restraint for the battery cell 220 placed inside, assisting in rapid loading and rough positioning. When specific process requirements are met (e.g., the need to protect the edge of the battery cell 220 or existing structure), the depth and contour of the groove can be designed to provide inclusive support for the battery cell 220, so that the pressure of the pressing roller mainly acts on the transfer area in the center of the battery cell, while the edge area receives a certain degree of stress buffering.

[0034] The combination of vacuum adsorption and a height-adjustable groove structure results in synergistic effects on the adaptability of the process sequence. For example, during the loading stage of the solar cell 220, the stage surface can be lowered to a low position or kept flat to facilitate the placement of the solar cell 220. After placement, vacuum adsorption is activated to fix the solar cell 220. Subsequently, the stage can drive its surface or local areas to perform precise lifting movements according to alignment or bonding requirements. This "height-adjustable" capability allows the stage to not only achieve the vertical (Z-axis) bonding movement mentioned above, but also to adjust the shape of the solar cell 220 support surface at a microscale. For example, by making the central area of ​​the support surface slightly higher than the edge (or vice versa), a slight, controllable prestress can be applied to the solar cell 220 to correct its minor initial deformation, ensuring more comprehensive and uniform contact with the transfer film above during pressing. This ensures that large-size, thin silicon wafers are subjected to uniform force during the transfer process, avoiding fragmentation or poor transfer caused by local pressure concentration. The adsorption pores and the height-adjustable groove structure are designed to enhance the platform's ability to fix, position, and adapt to the shape of the battery cell 220.

[0035] Considering the different requirements of transfer process routes, such as the need to segment the patterned transfer film 210 into fixed lengths according to the size of the battery cell 220, some methods remove the base film of the transfer film, while others retain it. The apparatus of this application may also optionally include a cutting component 180, which is configured on the transport path of the patterned transfer film 210. Depending on the specific process flow design, its position can be before or after the pressing roller assembly 120. The cutting component 180 can be implemented mechanically, including using a precision cutting knife driven by a cylinder or servo motor, utilizing the cooperation of a die or anvil roller to cut the film; or it can be non-contact cutting, such as a laser cutting system, which melts or ablates the film material by controlling the path and energy of the laser beam. The optional integration of the cutting component 180 increases the equipment's adaptability and compatibility with different transfer printing processes, enabling the same equipment platform to meet diverse production cycles and material handling requirements through configuration adjustments.

[0036] To complete the entire transfer cycle and achieve clean recycling or treatment of the carrier film, the apparatus of this application may optionally include a film-tearing and film-collecting assembly 160 for peeling off the release film carrying the pattern and winding and collecting the peeled release film. The specific configuration of the film-tearing and film-collecting assembly 160 typically includes a peeling mechanism and a winding mechanism. The peeling mechanism can employ a fixed peeling blade, peeling rod, or an adjustable-angle peeling roller. Its function is to provide a physical separation point with a specific angle and radius of curvature for the separation of the film material, guiding the film material to separate smoothly along a set path and tension. The winding mechanism typically includes a motor-driven winding shaft, possibly supplemented by a tension sensor and a floating roller, to apply appropriate winding tension to the peeled film material, ensuring its flat and orderly winding and recycling.

[0037] To achieve precise control of the pressing force during the transfer process, the pressing roller assembly 120 further includes a pressure adjustment component. This allows the linear or surface pressure applied to the film-sheet composite to be set and adjusted according to different process requirements (such as slurry characteristics, film thickness, and cell type 220), and to remain stable during the pressing process. A common implementation uses a pneumatic or hydraulic control system, indirectly controlling the pressing force by adjusting the medium pressure within the cylinder that drives the heating roller to press down. The pressure adjustment component may include a precision pressure regulating valve, a pressure sensor, and a corresponding closed-loop feedback controller, forming a pressure servo control system. Another implementation uses a precision ball screw or linear motor mechanism driven by a servo motor to directly control the downward displacement of the heating roller, and precisely sets and maintains the required pressing force through a force sensor or by controlling the output torque of the motor. The pressure adjustment component allows for setting an optimal process pressure value through a human-machine interface based on the specific "slurry-film-silicon wafer" combination, enabling digital management of process parameters. During the lamination process, this component can overcome fluctuations caused by film thickness tolerances, slight warping of the solar cell 220, or mechanical clearances in the equipment, maintaining a stable pressure value. This ensures consistency of transfer pressure conditions within the same batch and between different batches. Working in conjunction with the aforementioned temperature control system, it constitutes a refined and programmable control of the thermodynamic environment of the transfer interface.

[0038] To expand the application of this device in bifacial solar cells, the mounting platform 150 can optionally integrate a flipping component. This component allows the stage, which holds and holds the solar cell 220, to rotate around a specific axis, enabling the solar cell 220 to be flipped at a specific angle (typically 180 degrees) after one side of the transfer is completed, in preparation for processing the other side or positioning at a different angle. This can be an end effector of a robotic arm with a flipping function, with the stage as part of the actuator, and the robotic arm performing the actions of picking up, flipping, and repositioning the cell. Bifacial solar cells require electrode grid lines to be fabricated on both sides of the silicon wafer. With the integrated flipping component, a single machine can sequentially complete the transfer, flipping, and second-side transfer of the solar cell 220 after a single loading (requiring appropriate film path and lamination station design), achieving the integration and automation of the bifacial transfer process. This reduces intermediate buffering and handling steps, shortens production cycle time, and reduces the risk of breakage and contamination caused by multiple loading and unloading operations.

[0039] Please refer to Figures 2-4. This application also provides a method for transferring grid lines on a battery cell 220, which uses the aforementioned battery cell grid line transfer device and includes the following steps: placing the battery cell 220 on a stage, and moving the stage under the transport path of the patterned transfer film 210; aligning the grid line pattern 230 on the patterned transfer film 210 with the corresponding position on the battery cell 220; moving the stage vertically toward the surface of the patterned transfer film 210, so that the patterned transfer film 210 is adhered to the surface of the battery cell 220; passing the battery cell 220 with the patterned transfer film 210 adhered to it through the pressing roller assembly 120 for heating and pressing; removing the base film of the patterned transfer film 210 from the surface of the battery cell 220, leaving the grid line pattern 230 on the surface of the battery cell 220.

[0040] In the transfer method, the battery cell 220 is first placed on a carrier platform. The platform moves under the conveyor path of the patterned transfer film 210, utilizing the carrying and moving functions of the bonding carrier platform 150. Its function is to achieve the spatial transfer of the battery cell 220 from the initial loading position to the core bonding station. Driven by the first moving component, the platform can move horizontally (e.g., along the X and Y axes) to a precise position directly below the patterned transfer film 210, a position typically pre-calibrated by the equipment coordinate system. Subsequently, the grid pattern 230 on the patterned transfer film 210 is aligned with the corresponding position on the battery cell 220. Specifically, the vision inspection component 140 (typically including upper and lower cameras) captures the position of the edge or preset mark on the battery cell 220, and the position of the corresponding alignment mark on the patterned transfer film 210, respectively. The control system (e.g., an industrial computer) calculates the deviation between the two in planar coordinates (X, Y) and rotation angle (R) using image processing algorithms. The deviation data is converted into motion commands, which drive the stage (XYR platform) to perform minute translational and rotational movements to compensate for the deviation, so that the relative positional relationship between the micron-level grid pattern 230 on the film and the predetermined area on the solar cell 220 reaches the accuracy required by the process.

[0041] After alignment, the stage moves vertically towards the surface of the patterned transfer film 210, causing the patterned transfer film 210 to adhere to the surface of the battery cell 220. The stage moves in a direction perpendicular to the film surface (Z-axis), actively and smoothly pushing the battery cell 220 against the back of the stationary or low-speed moving patterned transfer film 210, achieving initial full contact. Next, the battery cell 220 with the patterned transfer film 210 adhered is passed through the pressing roller assembly 120 for heating and pressing. The initially adhered "film-cell" composite is transported or moved through the pressing roller assembly 120. The heating roller of the pressing roller assembly 120 rolls and presses the composite under a preset temperature (controlled by the first temperature control component) and pressure (controlled by the pressure adjustment component). Through the combined action of uniform heat and pressure, the conductive paste in the groove of the patterned transfer film 210 completes the transfer from film to cell, and promotes the initial curing of the paste or the densification of the sintering precursor.

[0042] Finally, the base film of the patterned transfer film 210 is removed from the surface of the solar cell 220, leaving the grid pattern 230 on the surface of the solar cell 220. The grid paste has adhered to the solar cell 220, and the carrier base film can be selectively peeled off. By guiding the base film to separate from the surface of the solar cell 220 at a specific angle (such as through a peeling blade), the magnitude and direction of the peeling force can be controlled. Through a smooth and controllable peeling process, the damage of the separation force to the fragile grid structure that has just been transferred and is not yet fully cured is minimized, ensuring that the integrity of the transfer pattern is preserved on the surface of the solar cell 220.

[0043] To optimize the initial bonding state of the transfer interface and create more favorable conditions for subsequent main roller pressing, the method of this application may further include, in embodiments, a preliminary pressing step using a heating plate 170 and a stage in the bonding process between the patterned transfer film 210 and the battery cell 220. This step is not a replacement for the main heated roller pressing, but rather a preliminary supplement, occurring after vertical bonding and before entering the pressing roller assembly 120. This is achieved through the heating plate 170 and the bonding support platform 150 in the device. After the stage drives the battery cell 220 to rise vertically and make contact with the patterned transfer film 210, the heating plate 170, equipped with a second moving component, can move synchronously or later to directly above the bonding area. Subsequently, under the control of its own temperature control system, the heating plate 170 applies a distributed planar pressure or localized linear pressure to the back of the film material at a set temperature. Simultaneously, the stage holds the position of the battery cell 220 through its vacuum adsorption and can selectively maintain the temperature of the battery cell 220 through its second temperature control component. This initial pressing action can be achieved by pneumatic or electric downward pressure on the entire or partial area of ​​the heating plate 170, or by the stage applying further upward pressure while the heating plate 170 remains in position, forming a "clamping" type of initial pressing. Setting up initial pressing allows for phased and refined control of the transfer interface bonding process. The "pre-pressing" or "pre-lamination" step helps reduce interface defects that may occur in the subsequent high-speed rolling stage due to insufficient ink flow. Simultaneously, because the initial pressing is relatively static or low-speed, the shear force is smaller, reducing the risk of disturbing the already aligned pattern. Introducing a preliminary pressing step involving the heating plate 170 and the stage essentially decomposes the transfer pressing process into two stages: "initial static / low-speed pressing" and "final dynamic rolling," which helps to broaden the process window and improve the bonding quality and uniformity of the transfer interface.

[0044] The following two specific implementation steps further illustrate the technical solution of this application.

[0045] Referring to Figure 3, in the first embodiment, the cutting component 180 is not provided. After the transfer is completed, the base film of the patterned transfer film 210 remains continuous and is peeled off and recycled from the surface of the solar cell 220. First, the patterned transfer film 210 roll filled with conductive paste is mounted on the unwinding component 110. Through a closed-loop tension control system consisting of a servo motor, tension sensor, and floating roller, the film is stepped and pulled to the top of the laminating station with constant tension and then stationary. At the same time, the laminating support platform 150 (whose surface is made of aluminum alloy with a Teflon coating to provide uniform heat conduction, stable vacuum adsorption, and prevent damage to the silicon wafer) supports and adsorbs the solar cell 220. The system uses an industrial control computer as the control core, integrating a motion control card and a vision system. The vision inspection component 140 includes an "upper-lower" dual CCD camera. The upper camera acquires the position of the solar cell 220, and the lower camera acquires the alignment marks on the film. The resolution of both can reach the micrometer level, combined with a sub-pixel processing algorithm. The industrial control computer calculates the deviations between the two in the X and Y coordinates and rotation angles in real time, and drives the XYR high-precision servo platform attached to the stage (where the R axis uses a DD direct drive motor to eliminate backlash) to perform spatial motion compensation, which can achieve an alignment accuracy of better than 10μm between the film pattern and the solar cell 220 and an angle deviation of less than 0.1°.

[0046] After alignment, the system initiates the preheating and rolling process. First, the transfer film is locally preheated by a movable heating plate 170; simultaneously, a second temperature control component integrated inside the stage (such as a closed-loop circuit composed of resistance heating wires and thermocouples) preheats the bottom of the battery cell 220. The stage then rises vertically, bringing the battery cell 220 into contact with the back of the film (specifically, the patterned grid lines). After bonding, the battery cell 220 and the transfer film are combined and conveyed to the pressing roller assembly 120. This assembly includes a heated steel roller (made of high-rigidity, high-straightness alloy steel, with heating tubes and thermocouples evenly arranged inside, achieving precise temperature control with an axial temperature difference of less than ±1.5℃ through a PID algorithm) and a pressure adjustment component. The pressure adjustment component uses a servo-controlled cylinder. By controlling the cylinder pressure and downward displacement, a constant linear pressure can be precisely set and maintained. Combined with precise installation and leveling, this ensures that the pressure distribution unevenness in the rolling area is less than 5%. The rolling speed can be precisely adjusted by a servo motor and matched with the tension control system. The heating rollers apply hot-pressing to the film-sheet composite material at a set temperature, pressure, and speed, promoting slurry transfer and initial curing. After hot pressing, the battery cell 220 continues to move downstream together with the transfer film.

[0047] At the peeling station, an adjustable peeling blade mechanism is installed. The solar cell 220 with transferred grid lines continues to advance along the conveyor path under the support of the vacuum adsorption platform, while the continuous base film is smoothly separated at a specific peeling angle under the guidance of the peeling blade. The smooth peeling process, combined with the constant tension winding of the winding assembly 130, effectively protects the morphology of the newly transferred grid lines. The peeled base film is then wound back by the downstream winding assembly 130 under tension fluctuations of less than ±2%. The solar cell 220 with completed transfer is then removed by the subsequent conveying mechanism. The entire system adopts a modular design with an intuitive human-machine interface. Process parameters (temperature, pressure, speed, tension, and visual parameters) are digitally stored as a "recipe," reducing new product debugging time to within half an hour.

[0048] Referring to Figure 4, in the second embodiment, a cutting component 180 is integrated after the pressing and transfer station to remove the residual base film on the battery cell 220. The conveying, visual alignment, preheating, and heated rolling processes of the patterned transfer film 210 are similar to those in Embodiment 1, relying on a centrally controlled "upper-lower" dual CCD visual alignment system, a high-precision XYR (DD motor) motion platform, multi-level temperature control (movable heating plate 170, stage heating, PID temperature control of heated steel rollers), and a servo pressure control system to ensure high-precision alignment and a uniform hot-pressing transfer environment. After the hot-pressing transfer is completed, the "film-sheet" composite is not immediately peeled off, but first passes through a cutting component 180.

[0049] The cutting assembly 180 is a precision laser cutting system (e.g., using a carbon dioxide laser). Its optical path is linked to the control system. Based on the size and contour of the solar cell 220, it cuts the local base film covering the solar cell 220, along with the waste film around it, from the continuous roll, leaving an independent film of the same size on top of each solar cell 220. The cutting action here is synchronized with the main conveyor line and precisely coordinated by the control system. Subsequently, the independent film (including the base film and the grid lines transferred) that has been temporarily bonded to the solar cell 220 is removed from the main conveyor line. At this point, the system mainly peels off and rewinds the waste film generated after cutting, and the peeling and rewinding method is similar to the treatment of continuous waste film in Embodiment 1.

[0050] The residual base film on the surface of the solar cell 220 is subsequently removed by solvent dissolution. Specifically, a specific solvent (e.g., an organic solvent selectively dissolving the base film material) is sprayed onto the solar cell 220 with the film, causing the base film material to dissolve and leaving the grid pattern 230 attached to the surface of the solar cell 220. This is followed by cleaning and drying processes. In this embodiment, the preheating temperature and temperature control uniformity of the stage are particularly important, as they need to be considered in relation to the possible thermal decomposition process temperatures to avoid thermal stress shocks. Through customized selection and matching of the base film material and subsequent post-processing steps, a high-precision grid structure is finally formed on the surface of the solar cell 220.

[0051] Alternatively, a thermal decomposition removal method can be selected, in which the cell 220 is placed in a programmable high-temperature furnace or a specific heating station, and heated to above the thermal decomposition temperature of the base film polymer under a controlled atmosphere and a set heating curve (for example, for polyimide films, it can be processed within a certain temperature range), so that the base film is pyrolyzed or ashed, thereby leaving only the cured conductive grid lines on the cell 220.

[0052] As described above, this application provides a battery cell grid line transfer device and method to achieve high-precision and high-efficiency grid line pattern transfer. The device is constructed in a modular manner, and its core includes: a roll-to-roll transport system, consisting of an unwinding assembly and a rewinding assembly, for the automated supply and recovery of the patterned transfer film; a high-precision vision alignment and motion system, consisting of vision detection components (such as upper and lower cameras) and a bonding support platform, wherein the bonding support platform integrates a stage for fixing the battery cell and a first moving component for driving the stage to perform multi-axis (X, Y, R and vertical Z-axis) precision movement, achieving micron-level precise alignment through real-time visual detection and position compensation of the film and the sheet; and a hot-press transfer system, mainly consisting of a pressing roller assembly (including a heating roller, a first temperature control component and a pressure adjustment component), for completing the transfer of slurry from film to sheet under precise temperature and pressure control conditions. To optimize the thermal conditions before transfer, the device may also include a movable heating plate for localized preheating of the film, and a second temperature control component integrated within the stage for bottom preheating of the solar cells, forming a bidirectional preheating process to reduce thermal shock and promote interfacial bonding. The stage surface may be provided with vacuum adsorption pores and an adjustable support structure to enhance the stable fixation and morphological adaptability of brittle solar cells.

[0053] The transfer method based on the aforementioned device includes the following core steps: placing the solar cell on a stage and moving it under the film; achieving precise alignment between the film pattern and the solar cell using a vision system; driving the stage vertically upward to initially bond the solar cell and film; subjecting the "film-cell" composite to heated rolling pressure via a pressing roller assembly; and removing the base film from the surface of the solar cell to complete the transfer. In specific implementations, a preliminary pressing step, completed collaboratively by a heating plate and the stage, can be added after the initial bonding to optimize the interface bonding quality in stages.

[0054] In summary, this application provides a solution that can adapt to different process requirements and improve the accuracy, uniformity, production efficiency, and product yield of grid line transfer by integrating roll-to-roll transport, high-precision visual alignment and motion compensation, uniform and controllable hot pressing transfer, and optional flexible process modules.

[0055] The above is only one specific implementation of this application, and any other improvements made based on the concept of this application shall be considered within the scope of protection of this application.

Claims

1. A battery cell grid line transfer device, characterized in that, The system includes an unwinding assembly, a pressing roller assembly, a winding assembly, a vision inspection assembly, and a bonding support platform. The patterned transfer film is conveyed from the unwinding assembly to the winding assembly in a roll-to-roll manner. The pressing roller assembly is positioned along the conveying path. The bonding support platform includes a platform for supporting solar cells and a first moving component. The first moving component drives the platform to move to a position along the conveying path and can move perpendicularly to the surface of the patterned transfer film. The pressing roller assembly includes a heating roller and a first temperature control component. The vision inspection assembly is used to detect the position of the patterned transfer film and the platform.

2. The battery cell grid line transfer device according to claim 1, characterized in that, It also includes a heating plate disposed on the patterned transfer film transport path, the heating plate including a second moving component, the second moving component driving the heating plate to move position.

3. The battery cell grid line transfer device according to claim 1, characterized in that, The bonding support platform includes a second temperature control component, which is used to control the platform temperature.

4. The battery cell grid line transfer device according to claim 3, characterized in that, The stage also includes adsorption pores.

5. The battery cell grid line transfer device according to claim 1, characterized in that, It also includes a cutting component.

6. The battery cell grid line transfer device according to claim 1, characterized in that, It also includes a film tearing and film collecting assembly.

7. The battery cell grid line transfer device according to claim 1, characterized in that, The pressing roller assembly includes a pressure adjustment component.

8. The battery cell grid line transfer device according to claim 1, characterized in that, The bonding support platform also includes a flipping component.

9. A method for transferring grid lines on a solar cell, comprising using the solar cell grid line transfer apparatus according to any one of claims 1-8, characterized in that, The process includes the following steps: placing the solar cell on a carrier stage, moving the carrier stage under the transport path of the patterned transfer film; aligning the grid pattern on the patterned transfer film with the corresponding position on the solar cell; moving the carrier stage vertically towards the surface of the patterned transfer film, so that the patterned transfer film adheres to the surface of the solar cell; passing the solar cell with the patterned transfer film adhered to it through a pressing roller assembly for heating and pressing; removing the base film of the patterned transfer film from the surface of the solar cell, leaving the grid pattern on the surface of the solar cell.

10. The battery cell grid line transfer method according to claim 9, characterized in that, It also includes using a heating plate and a stage to perform preliminary pressing in the process of bonding the patterned transfer film and the battery cell.

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