Fully automated 1GW solar module production line equipment.

Introduction to the Process Flow of PV Module Production Line:

Cell Testing: Due to the randomness of the conditions during cell production, the performance of the cells produced is not identical. To effectively combine cells with uniform or similar performance, they need to be classified according to their performance parameters. Cell testing involves classifying cells based on the size of their output parameters (current and voltage) to improve cell utilization and produce qualified module components.

Front Electrode Welding: This process involves welding the bus bars onto the front (negative) main grid line of the cell. The bus bars are made of tin-plated copper strips and are welded in a multi-point form to the main grid line using an infrared lamp as the heat source. The length of the bus bar is about twice the length of the cell side. The excess bus bar is connected to the back electrode of the next cell when it is welded to the back. (Manual welding is used in our company).

Back Stringing: Back stringing involves connecting cells together to form a module string. Our current process uses manual positioning of the cells mainly by means of a film template plate with 36 grooves for placing the cells. The size of the groove corresponds to the size of the cell, and the location of the groove has been designed. Different specifications of modules use different templates. The operator uses a soldering iron and solder wire to weld the front electrode (negative) of the previous cell to the back electrode (positive) of the next cell, thus connecting them one by one and welding the positive and negative poles of the module string into leads.

Laying and Pressing: After back stringing and passing inspection, the module string, glass, cut EVA, fiberglass, and back panel are laid out in a certain order and prepared for pressing. The glass is coated with a reagent in advance to increase the bonding strength between the glass and EVA. When laying out, care is taken to ensure the relative position of the cell string and the materials such as glass, and the distance between the cells is adjusted as a foundation for pressing. (Layering sequence: from bottom to top: glass, EVA, cell, EVA, fiberglass, back panel).

Module Pressing: The laid-out cells are placed in a laminator, the air inside the module is removed by vacuum pumping, and then heated to melt the EVA to bond the cell, glass, and back panel together. After cooling, the module is removed. Lamination is the key step in module production, where the lamination temperature and time are determined based on the properties of the EVA.

Trimming: During lamination, EVA melts and extends outward due to pressure, creating burrs. Therefore, after lamination, they should be removed.

Framing: Similar to putting a frame around a mirror, an aluminum frame is installed on the glass module to increase its strength, further sealing the cell components and extending their lifespan. The gap between the frame and the glass module is filled with silicone resin, and the frames are connected using angle keys.

Junction Box Welding: A box is welded at the lead wire of the module back to facilitate the connection between the cell and other equipment or cells.

High-Voltage Testing: This involves applying a certain voltage between the module frame and the electrode lead wires to test the module's withstand voltage and insulation strength to ensure that the module is not damaged under harsh natural conditions like lightning strikes.

Module Testing: The purpose of testing is to calibrate the output power of the cell, test its output characteristics, and determine the quality level of the module.