1. Battery test
Due to the randomness of the cell production conditions, the performance of the batteries produced is not the same, so in order to effectively combine the batteries with the same or similar performance, they should be classified according to their performance parameters; the battery test is to classify the battery by testing the output parameters (current and voltage) of the battery, so as to improve the utilization rate of the battery and make a qualified battery assembly.
2. Front welding
The front side welding is to weld the busbar to the main grid line of the front side (negative electrode) of the battery. The busbar is a tin-plated copper tape. The welding machine used can spot-weld the ribbon on the busbar in the form of multiple points. The heat source for welding is an infrared lamp, which uses the thermal effect of infrared rays for welding. The length of the welding strip is about twice the length of the battery side. The extra welding strip is connected to the back electrode behind the battery sheet during back welding.
3. Serial connection on the back
The backside series connection is to connect the batteries in series to form a component string. The positioning of the battery mainly relies on a mold plate with grooves for placing the battery slices. The size of the groove corresponds to the size of the battery. The position of the groove has been designed. Different specifications of components use different templates. The operator uses an electric soldering iron and solder wire to weld the front electrode (negative electrode) of the “front battery” to the back electrode (positive electrode) of the “back battery”, so that the battery pieces are connected in series and the leads are welded to the positive and negative electrodes of the module string.
4. Laminated laying
After the back side is connected in series and passed the inspection, the series connected battery slices, glass, cut EVA, glass fiber, and backplane are laid in a certain level and ready to be laminated. The glass is coated with a layer of reagent in advance to increase the bonding strength between the glass and EVA. When laying, ensure the relative position of the battery string and glass and other materials, adjust the distance between the batteries, and lay a good foundation for lamination. Laying levels from bottom to top are: glass, EVA, battery, EVA, glass fiber, backplane.
5. Module lamination
Put the laid battery into the laminator, draw out the air in the module by vacuuming, and then heat to melt the EVA to bond the battery, glass and back plate together; finally cool and take out the module. The lamination process is a key step in component production, and the lamination temperature and lamination time are determined by the properties of EVA. Currently, fast-curing EVA is mainly used, the laminating cycle time is about 25 minutes, and the curing temperature is 150°C.
During lamination, the EVA melts and expands and solidifies due to pressure to form burrs, so it should be cut off after lamination.
The glass assembly is equipped with an aluminum alloy frame similar to the glass assembly, which increases the strength of the assembly, further seals the battery assembly, and prolongs the service life of the battery. The gap between the frame and the glass component is filled with polysiloxane resin, and the frames are connected by corner bonds.
8. Welding junction box
Solder a box at the lead on the back of the module to facilitate the connection between the battery and other devices or batteries.
The solar junction box (Figure 1) provides users with a combined connection plan for solar panels. It is a connector between the solar cell array composed of solar cell modules and the solar charging control device. And it is a cross-domain comprehensive design integrating electrical design, mechanical design and material science, and is an important component of solar modules.
The structure of the junction box: The general solar junction box includes an upper cover and a lower box. The upper cover and the lower box are connected by a rotating shaft, and are characterized in that a number of wiring sockets are arranged in parallel in the lower box, and each two adjacent wiring sockets are connected by one or more diodes. The upper cover or lower box is made of thermally conductive materials, and its product types now include: glue-filled junction box, screen wall junction box, small component junction box, etc.