Introduction to the Eight Major Process Steps in the Production Process of Photovoltaic Modules

　　The production process of photovoltaic modules is an important component of the solar photovoltaic industry chain. By encapsulating thin solar cells one by one, they can operate reliably in harsh outdoor environments.

　　The current mainstream processing technology for photovoltaic modules adopts EVA film packaging, which consists of multiple processes such as cell detection, cell single welding, cell string welding, module stacking, module lamination, installation of frames and junction boxes, finished product testing, and packaging and storage. Each process is interrelated, therefore, the level of craftsmanship in each process directly affects the quality and grade of the product.

　　Photovoltaic module processing technology

　　The 1th process

　　The first process is battery cell inspection. As the main raw material for photovoltaic module processing, the performance of solar cells directly determines the quality of photovoltaic modules. Therefore, in addition to detecting their appearance, color difference, and EL defects, it is also necessary to test the operating current, operating voltage, power, and conversion efficiency of the cells under specific lighting and temperature conditions. Its testing is mainly completed through cell sorting equipment.

　　The 2th process

　　The second process is the welding of individual battery cells. When welding, pinch one end of the welding strip with your left hand about 1/3 of the way, place the welding strip flat on the main grid line of the battery cell, and the other end of the welding strip contacts the grid line on the battery cell; Hold a soldering iron in your right hand and gently press and solder along the solder strip with even force from left to right. When welding, the starting point of the soldering iron tip should be on the left side of the single piece, and the flat surface of the soldering iron tip should always be tightly attached to the solder strip during welding. Welding should be firm, free of burrs, virtual welding, and tin slag, with a smooth and beautiful surface. Nowadays, most factories have been equipped with automatic welding, eliminating the need for manual welding and reducing the fragmentation rate.

　　The 3th process

　　The third process is the string welding of battery cells. The operation process is as follows: place the specified number of welded battery cells on the template with the back facing upwards, gently press down on two battery cells with one hand, and make them stick to the heating template tightly. According to the specified spacing (2 ± 0.5 mm), use a soldering iron to press and solder the solder bar leading out of the next battery cell onto the back electrode of the previous battery cell. When welding, it is required that the solder bar be welded flat, with a straight appearance, no protruding solder bumps, and no virtual soldering phenomenon.

　　The 4th process

　　The fourth process is stacking. Lift the tempered glass onto the laminated workbench, with the suede surface of the tempered glass facing upwards, and lay a layer of EVA flat on top of the tempered glass. EVA has a margin of ≥ 5mm on all four sides of tempered glass. Note that the smooth surface of the EVA should face the tempered glass velvet surface. Place the positioning template that matches the module board type on the EVA. The battery string should correspond to the head and tail templates respectively. According to the positive and negative symbols marked on the template, place the battery string correctly on the EVA with the anti reflection film surface facing downwards.

　　After placing the battery string in place, measure the distance between the battery cells with a steel ruler according to the drawing requirements and positioning template, and adjust the position of the battery string. According to the component assembly diagram and voltage requirements, weld the busbar correctly and attach the barcode to the designated position. Lay the EVA with its suede facing the battery string, then lay the TPT and conduct EL testing to confirm that there are no hidden cracks, virtual soldering, delamination, black chips, or other defects. Visual inspection of the components is also required to confirm the presence of foreign objects.

　　The 5th process

　　The fifth process is lamination. Start the laminating machine according to the operating procedures, adjust the laminating temperature and evacuation time based on the characteristics of EVA, and record technical parameters such as temperature and pressure on the operation record sheet; Place one layer of high-temperature non stick cloth on the heating plate inside the laminating machine, and feed the assembled tempered glass components downwards into the middle of the laminating machine heating plate. Then place another layer of high-temperature non stick cloth, press the closing button, and the laminating machine enters the automatic control system. After the lamination is completed, the laminating machine automatically opens the lid and promptly removes the processed components, requiring that the chips inside the components are free of foreign objects, fragments, cracks, etc.

　　The 6th process

　　The sixth process is framing. Apply sealant evenly in the grooves of the aluminum alloy frame, insert the components into the grooves, and start the framing machine to complete the framing process. Apply sealant evenly at the junction of TPT and aluminum alloy on the back of the component. Apply sealant evenly around the back of the corresponding specification junction box and the root of the lead wire, stick the junction box, and connect the lead wire to the junction box. Cure at room temperature and certain humidity. Requirement: The frame installation should be flat and not bent, and the gap at the aluminum alloy right angle connection should not exceed 0.2mm. The diagonal error of the two aluminum alloy frames should be less than 4mm.

　　The 7th process

　　The seventh process is cleaning. Tear off the plastic film on the surface of the aluminum profile and clean the various pollutants on the surface of the components with alcohol solution to ensure a clean and pollution-free appearance of the components.

　　The 8th process

　　The eighth process is the testing of finished components. According to the operating procedures of the solar module tester, first calibrate the solar module tester with standard components in the same environment, and make calibration records. Place the photovoltaic module to be tested, connect the positive and negative poles, test the module, calculate the electrical performance parameters of the module through comparison and analysis, and record them.