Method for quickly adjusting overprinting offset of main and auxiliary grid patterns

Abstract

The invention discloses a method for rapidly adjusting overprinting offset of main and auxiliary grid patterns, and aims to solve the problems of tedious steps, long time consumption, generation of reworked pieces, high operation difficulty and the like in main and auxiliary grid overprinting debugging in existing solar cell screen printing. A plastic battery piece simulation model consistent with a battery piece produced in a production line in size is manufactured, and the surface of the plastic battery piece simulation model is coated with a preset main grid pattern. By means of the process of screen calibration, simulation printing and offset debugging and repeated debugging, the offset condition of main grid printing is rapidly determined through a simulation model, machine parameters are adjusted, and the steps of drying and auxiliary grid printing in the prior art are omitted. According to the method, the debugging time is shortened to about 3 minutes, no reworked piece is generated, meanwhile, operation is easy and convenient, new employees are easy to master, the efficiency of main and auxiliary grid overprinting debugging on the solar cell production line is greatly improved, the production cost is reduced, and remarkable economic benefits and application prospects are achieved.

Description

Technical Field

[0001] This invention relates to the field of solar cell manufacturing technology, and more specifically to a method for rapidly adjusting the overprinting offset of main and sub-grid patterns. Background Technology

[0002] In the production of solar cells, after forming a PN junction through processes such as texturing, diffusion, and PECVD, electrodes need to be fabricated on the cell surface to conduct the current generated by light. Screen printing is a key process for electrode fabrication, forming fine grid lines and electrodes on the front and back of the cell to achieve current collection and transmission. Its quality directly affects the photoelectric conversion efficiency and equipment reliability.

[0003] Currently, mainstream printing presses in the industry (such as those from Maiwei, Kelonwei, and Jiejiachuang) employ two methods for wafer alignment during silicon wafer printing: for main grid electrode printing, the camera captures the positions of the four edges of the silicon wafer; for secondary grid line printing, the camera captures the positions of the mark points printed on the main grid screen. Because the main grid screen captures a larger area of ​​the silicon wafer edges, resulting in higher accuracy, while the secondary grid screen captures a smaller area of ​​mark points, resulting in lower accuracy, significant adjustments to the overprinting of the main and secondary grid patterns are required each time the screen is changed.

[0004] The existing adjustment method is as follows: after printing the main grid, it is oven-dried and then overprinted with the secondary grid. The appearance misalignment is checked and the printing parameters of the main grid are adjusted. The above steps are repeated until the overprinting is qualified. This method has problems such as being cumbersome, time-consuming and labor-intensive, easily generating a large number of rework pieces, and being unfriendly to new employees, which seriously affects the workshop's production capacity and increases production costs. Summary of the Invention

[0005] The purpose of this invention is to provide a method for quickly adjusting the overprinting offset of the main and secondary grid patterns, so as to solve the problems of cumbersome and time-consuming main and secondary grid overprinting debugging steps, the large number of rework pieces, and the high difficulty of operation in the prior art.

[0006] The technical solution of the present invention to solve the above technical problems is as follows:

[0007] A method for quickly adjusting the overprinting offset of primary and secondary grid patterns includes the following steps:

[0008] Preparation of battery cell simulation model: Select plastic material that is not easily deformed and has good toughness and strength to make a battery cell simulation model with the same thickness, length and width as the mass-produced battery cell on the production line. The surface of the simulation model has a main grid pattern pre-set by a film coating method, and the main grid pattern cannot be wiped or cleaned.

[0009] Screen calibration: After replacing the main grid screen, calibration is performed using the Mark points printed on the screen graphic to adjust the camera's X / Y / Z axis errors to the preset range and save the data;

[0010] Simulation printing and offset adjustment: The battery cell simulation model is used for screen printing. After printing, the simulation model is removed and the alignment of the pattern formed by the printed paste with the preset main grid pattern on the surface of the simulation model is compared. If there is a left-right, up-down, or angular offset, the corresponding offset parameters of the machine are adjusted and saved.

[0011] Repeated debugging: Use a wiping tool to remove the paste from the surface of the simulation model. After drying, repeat the printing, comparison and parameter adjustment operations in step (3) until the printed paste pattern and the preset main grid pattern on the surface of the simulation model are completely overlapped, and the adjustment of the overprinting offset of the main and secondary grid patterns is completed.

[0012] In a further embodiment, in step one, the thickness, length, and width of the battery cell simulation model are completely consistent with the dimensions of the mass-produced battery cells on the production line; the preset main grid pattern is fixed to the surface of the simulation model by a coating method and does not fall off after being wiped with alcohol.

[0013] In a further embodiment, in step two, the preset range is defined as camera X / Y / Z axis error ≤ 0.005mm.

[0014] In a further embodiment, step three includes the machine tool's corresponding offset parameters, which include the translation parameters of the X-axis and Y-axis and the angle adjustment parameters of the Z-axis.

[0015] In a further embodiment, in step four, the wiping tool is an alcohol cloth; the "drying" refers to natural air drying or air drying at room temperature.

[0016] In a further embodiment, in step four, the phrase "the printed paste pattern and the preset main grid pattern on the surface of the simulation model are completely coincident" means that there is no offset when observed visually or the offset is ≤0.01mm when detected by an image recognition system.

[0017] The present invention has the following beneficial effects:

[0018] Significantly Improved Debugging Efficiency: This invention introduces a solar cell simulation model, eliminating the need for drying after main busbar printing and printing of sub-busbars in existing technologies. The simulation model is used directly for main busbar printing debugging. Actual testing shows that debugging time has been drastically reduced from approximately 10 minutes to about 3 minutes, greatly improving debugging efficiency on the production line and providing a strong guarantee for increasing overall production capacity.

[0019] Reduced production costs: By eliminating the need for multiple main and auxiliary grid printing processes and reducing the drying step, the need for 5-10 reworked cells during the commissioning process is avoided. Furthermore, the cell simulation model is reusable, requiring only a one-time investment in manufacturing costs, significantly reducing production costs compared to existing technologies.

[0020] Simple to operate and easy to learn: The debugging method of this invention has been greatly simplified, and new employees can master it after simple training. It no longer relies on complex multiple printing and drying processes, reducing the technical skill requirements for operators and improving the work efficiency and stability of operators on the production line. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the gripping range of the sub-grid printing camera on the production line.

[0022] Figure 2 This is a schematic diagram showing the gripping of the four edges of the silicon wafer for the main grid printing camera on the production line. Detailed Implementation

[0023] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0024] This invention creates a simulation model of a plastic solar cell that is resistant to deformation, has good toughness and strength, and whose thickness and dimensions are consistent with those of mass-produced solar cells on the production line. This allows for rapid alignment adjustments during the main busbar screen offset adjustment process, making it easier for new employees to learn and use. Existing methods for adjusting main busbar screen offset involve numerous, cumbersome, and time-consuming steps, specifically: first, print the main busbar pattern on the solar cell; then, dry it in an oven; finally, print the sub-busbar pattern; then, remove the printed solar cell and check the alignment offset of the main busbar / sub-busbar patterns; finally, adjust the X / Y / Z axis parameters of the main busbar machine accordingly and save the settings; then, re-print the main busbar pattern on the solar cell. - Dry in an oven - Print the sub-grid pattern - Remove the printed cell and check the alignment offset of the main grid / sub-grid pattern - Adjust the X / Y / Z axis parameters of the main grid machine accordingly and save until the main grid / sub-grid pattern overlaps without offset; Steps for adjusting the main grid screen offset using the method of this invention: Take the cell simulation model and print the main grid pattern - Check the offset between the printed pattern and the pattern on the surface of the simulated cell - Adjust the X / Y / Z axis parameters of the main grid machine accordingly and save - Wipe off the paste on the surface of the cell simulation model with alcohol - Take the cell simulation model and print the main grid pattern until the pattern of the printed paste and the pattern of the simulated cell are completely aligned. The entire adjustment time of this invention has been reduced from 10 minutes to about 3 minutes, which greatly helps to improve production capacity. In addition, before the offset adjustment was carried out using the battery cell simulation model, each screen replacement would generate about 5-10 offset adjustment rework pieces, while the battery cell simulation model adjustment will not generate printing offset rework pieces, which can effectively reduce the number of rework pieces in the workshop. This kind of plastic battery cell simulation model is a one-time production investment that can be reused, greatly reducing the investment cost.

[0025] Production line auxiliary grid printing camera gripping such as Figure 1Within the red-framed area, each of the four cameras independently captures its corresponding position, effectively ensuring overall camera accuracy. In the actual printing process, the secondary grid printing only needs to accurately capture the Mark point area printed by the primary grid to essentially complete the graphic registration, without requiring significant alignment adjustments. Therefore, the main factor affecting the alignment of the primary and secondary grid graphics is the alignment adjustment of the primary grid graphic, which requires significant manual adjustments to the machine's X / Y / Z axis parameters.

[0026] The main grid printing camera on the production line grasps the four edges of the silicon wafer, such as... Figure 2 As shown, due to the wide edge range of the silicon wafer captured by a single camera, the printed pattern error is relatively large, posing a significant challenge to the overlay of the main busbar and sub-busbar patterns. Normally, changing the main busbar screen requires the following adjustments: first, print the main busbar pattern on the cell – dry it in an oven – print the sub-busbar pattern – check the alignment offset of the main busbar / sub-busbar patterns after printing – adjust the X / Y / Z axis parameters of the main busbar machine accordingly and save – re-print the main busbar pattern on the cell – dry it in an oven – print the sub-busbar pattern – check the alignment offset of the main busbar / sub-busbar patterns after printing – adjust the X / Y / Z axis parameters of the main busbar machine accordingly and save, until the main busbar / sub-busbar patterns overlap without offset. This entire debugging process is cumbersome and time-consuming, and during the entire debugging process, approximately 5-10 cells will be reworked due to misalignment, which significantly impacts the single-line production capacity and the number of reworked cells in the workshop.

[0027] Example 1

[0028] Preparation of the solar cell simulation model: A 0.2mm thick acrylic plastic sheet was selected and cut into a square of 156.75mm × 156.75mm, consistent with the size of the mass-produced solar cells on the production line. A main grid pattern was coated onto the surface of the plastic sheet using high-precision printing technology. The line width, spacing, and other parameters of this pattern were completely consistent with the requirements of the main grid in actual production. Furthermore, it underwent special treatment so that it would not peel off or deform after being wiped with common solvents such as alcohol.

[0029] Screen calibration: The newly replaced main screen is installed on the screen printing machine. Using the vision calibration system equipped on the screen printing machine, the X / Y / Z axes of the camera are adjusted by identifying the Mark points printed on the screen graphic. After several fine adjustments, the X-axis error of the camera is controlled within ±0.003mm, the Y-axis error within ±0.004mm, and the Z-axis error within ±0.005mm, ensuring high-precision positioning of the camera, and the calibration data is saved.

[0030] Simulation Printing and Offset Adjustment: The prepared battery cell simulation model was placed on the printing platform of the screen printing machine for screen printing. After printing, the simulation model was removed, and high-precision image comparison software was used to compare the pattern formed by the printed ink with the preset main grid pattern on the surface of the simulation model. It was found that the pattern had an offset of 0.1mm in the X-axis direction and 0.08mm in the Y-axis direction. Based on the offset, the X-axis translation parameter was increased by 0.1mm and the Y-axis translation parameter by 0.08mm in the screen printing machine's operating interface, and the adjusted parameters were saved.

[0031] Repeated adjustments: The ink on the surface of the simulation model was carefully wiped with an alcohol cloth and allowed to air dry naturally before printing again. Upon comparison of the images, the offset was found to have significantly decreased. After two repeated adjustments, the printed ink pattern perfectly overlapped with the preset main grid pattern on the simulation model surface, completing the adjustment of the main and secondary grid pattern overprinting offset. The entire adjustment process took approximately 3 minutes, and no rework was produced.

[0032] Example 2

[0033] Preparation of Solar Cell Simulation Model: A solar cell simulation model with a thickness of 0.25mm and a size of 166mm × 166mm was fabricated using polycarbonate plastic to adapt to the solar cell size of the specific production line. A precise main grid pattern was formed on the model surface using a coating process to ensure the clarity and stability of the pattern. Screen Calibration: After changing the screen, camera calibration was performed using the mark points on the screen. Advanced laser calibration equipment was used to control the X / Y / Z axis errors of the camera within 0.004mm, ensuring high calibration accuracy.

[0034] Simulated Printing and Offset Adjustment: After simulated printing, observation revealed an angular offset of approximately 0.5° between the printed graphic and the preset main grid graphic. In the screen printing machine's parameter settings, the Z-axis angle parameter was adjusted by 0.5°, while the X and Y-axis translation parameters were fine-tuned to further optimize the registration effect. Repeated Adjustment: After three rounds of ink wiping, reprinting, and parameter adjustments, perfect overlap between the printed graphic and the preset main grid graphic was achieved. This adjustment process took approximately 3.5 minutes, and no rework was produced. Furthermore, in subsequent actual production, the accuracy of main and secondary grid registration was effectively guaranteed, improving the product yield.

[0035] Through the above specific embodiments, the present invention can effectively achieve rapid and accurate overprinting and debugging, and has broad application prospects and significant economic benefits in actual production.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for rapidly adjusting the overprinting offset of primary and secondary grid patterns, characterized in that, Includes the following steps: Step 1: Prepare a battery cell simulation model: Select a plastic material that is not easily deformed and has good toughness and strength to make a battery cell simulation model with the same thickness, length and width as the mass-produced battery cell on the production line. The surface of the simulation model has a main grid pattern pre-set by a coating method, and the main grid pattern cannot be wiped or cleaned. Step 2: Screen calibration: After replacing the main screen, calibrate the screen by using the Mark points printed on the screen graphic to adjust the camera's X / Y / Z axis errors to the preset range and save the data; Step 3: Simulation Printing and Offset Adjustment: Use the battery cell simulation model for screen printing. After printing, remove the simulation model and compare the alignment of the pattern formed by the printed paste with the preset main grid pattern on the surface of the simulation model. If there is a left-right, up-down, or angular offset, adjust the corresponding offset parameters of the machine and save the settings. Step 4: Repeated debugging: Use a wiping tool to remove the paste from the surface of the simulation model. After it dries, repeat the printing, comparison and parameter adjustment operations in Step 3 until the printed paste pattern and the preset main grid pattern on the surface of the simulation model are completely overlapped, thus completing the adjustment of the overprinting offset of the main and secondary grid patterns.

2. The method for rapidly adjusting the overprinting offset of the main and sub-grid patterns according to claim 1, characterized in that, In step one, the thickness, length, and width of the battery cell simulation model are completely consistent with the dimensions of the mass-produced battery cells on the production line; the preset main grid pattern is fixed to the surface of the simulation model by a film coating method and does not fall off after being wiped with alcohol.

3. The method for rapidly adjusting the overprinting offset of the main and sub-grid patterns according to claim 1, characterized in that, In step two, the preset range is that the camera's X / Y / Z axis error is ≤0.005mm.

4. The method for rapidly adjusting the overprinting offset of the main and sub-grid patterns according to claim 1, characterized in that, In step three, the offset parameters of the machine tool include the translation parameters of the X-axis and Y-axis of the machine tool and the angle adjustment parameters of the Z-axis.

5. The method for rapidly adjusting the overprinting offset of the main and sub-grid patterns according to claim 1, characterized in that, In step four, the wiping tool is an alcohol cloth; the "drying" refers to natural air drying or air drying at room temperature.

6. The method for rapidly adjusting the overprinting offset of the main and sub-grid patterns according to claim 1, characterized in that, In step four, the phrase "the printed paste pattern and the preset main grid pattern on the surface of the simulation model are completely coincident" means that there is no offset when observed visually or the offset is ≤0.01mm when detected by an image recognition system.

Images