At present, the traditional encapsulation process commonly used in solar panels is: using TPT (composite fluoroplastic film) or glass plate as the substrate, and the front and back sides of the solar cell are lined with EVA film. During the encapsulation process, the laminated solar panels are heated to a certain temperature under vacuum condition, the EVA melts, and the molten EVA solidifies as the temperature decreases, thereby tightly fixing the solar cell sheet; then sealing the edge of the solar panel with the silicone material, then add frame and so on.
Waterproof Small Solar Panel
The main steps of the solar panel encapsulation process include the following:
1). Solar cell test:
Due to the randomness of solar cell manufacturing conditions, the performance of solar cells produced is not the same, so in order to effectively combine solar cells with consistent or similar performance, they should be classified according to their performance parameters;
Solar cell testing refers to classifying solar cells by testing the output parameters (current and voltage), in order to improve the utilization rate of solar cells, and produce quality solar panels.
The selected solar cell test equipment is in accordance with the general standard requirements, the illumination unevenness is <±2%, and the repeatability is <±1%.
2) Solar cell front welding:
Clean ultra-white tempered glass, prepare materials such as EVA, TPT and bus bar. The cutting size of EVA and TPT should be slightly larger than the size of glass. The interconnect strips need to be pre-soaked in the flux to remove oxides from the surface. The temperature during welding is controlled at 360 to 380 °C. The requirements for welding are firm, burr-free, free of solder and tin-free slag, and the surface of the interconnect strip is smooth and beautiful.
Using lead-free solder, first connect the interconnect strip on the main grid line on the front side of the cell, and then place it on the string soldering template. The interconnect strip of the latter solar cell is welded to the back electrode of the front solar cell to form a solar cell string with positive and negative lead wires.
3) Laminated laying:
After the tandem solar cell group has passed the inspection, the solar cell string, the glass and the cut EVA and the bottom plate are laid at a certain level to prepare for lamination. The glass is pre-coated with a primer to increase the bonding strength between the glass and the EVA. When laying, ensure the relative position of the solar cell string and glass and other materials, adjust the distance between the solar cells, and lay the foundation for lamination.
Laying level: from bottom to top: glass, EVA, solar cells, EVA, bottom plate.
4) Solar panel laminate:
The laid solar cell is placed in a laminating machine, the air in the solar panel is extracted by vacuuming, and then heated to fuse the EVA to bond the solar cell, the glass and the bottom plate together; finally, the solar panel is taken out by cooling. The lamination process is a key step in the production of solar panels. The lamination temperature and lamination time are determined by the nature of the EVA. After lamination, there should be no air bubbles in the solar panel, the solar cell strings are evenly spaced, and the bus bars are straight. The performance selection of the laminating machine equipment is very important, its temperature control accuracy is ≤ ± 1 ° C, temperature unevenness ink ≤ ± 2 ° C.
During lamination, the EVA melts and solidifies outward due to pressure to form a burr, so it should be cut off after lamination.
6) Mounting frame and junction box
Similar to adding a frame to the glass; attaching an aluminum frame to the glass laminated solar panel, increasing the strength of the solar panel, further sealing the solar panel, and prolonging the service life of the solar cell. The gap between the bezel and the glass laminated solar panel is filled with silicone resin. Each frame is connected by a corner key. When installing the junction box, bond it to the specified position on the back of the solar panel with silicone and connect the bus bar inside the solar panel to the cable of the junction box.
7) Solar panel test
The solar panel's output electrical characteristics and output power were tested using a solar panel tester. At the same time, it is necessary to test the parameters such as the pressure resistance and insulation strength to ensure that the solar panel meets the requirements of the standard.