Solar photovoltaic modules, also known as solar panels, are the core and most important component of a solar power generation system. Their function is to convert solar energy into electrical energy, which can then be either stored in batteries or used to power loads.
Individual solar cells cannot be used directly as power sources; to function as power sources, several individual cells must be connected in series and parallel and tightly packaged into a module. This article summarizes the manufacturing process of solar photovoltaic modules for your reference!
The production process of solar photovoltaic modules can be divided into: cell testing, front welding and inspection, back stringing and inspection, laying (glass cleaning, material cutting, glass pretreatment, laying), lamination, deburring (edge removal, cleaning), frame assembly (applying glue, installing corner keys, punching holes, framing, wiping off excess glue), welding junction boxes, high voltage testing, module testing and appearance inspection, and packaging and warehousing.
1. Battery Testing: Due to the randomness of battery cell manufacturing conditions, the performance of produced batteries varies. Therefore, in order to effectively combine batteries with consistent or similar performance, they should be classified according to their performance parameters. Battery testing involves classifying batteries by measuring their output parameters (current and voltage). This improves battery utilization and ensures the production of qualified battery modules.
2. Front-side soldering: This involves soldering the busbar to the main grid line on the front (negative) side of the battery. The busbar is a tin-plated copper strip. The soldering machine we use can spot-solder the strip to the main grid line at multiple points. The heat source for soldering is an infrared lamp (utilizing the thermal effect of infrared radiation). The length of the solder strip is approximately twice the side length of the battery. The excess solder strip is connected to the back electrode of the subsequent battery cell during back-side soldering.
3. Backside Serial Connection: Backside welding involves connecting 36 cells together to form a module string. The process we currently use is manual. The cells are positioned mainly by a mold plate with 36 grooves for placing the cells. The size of the grooves corresponds to the size of the cells, and the positions of the grooves are pre-designed. Different templates are used for different module specifications. The operator uses a soldering iron and solder wire to solder the front electrode (negative electrode) of the "front cell" to the back electrode (positive electrode) of the "rear cell". In this way, the 36 cells are connected together in series, and leads are soldered to the positive and negative terminals of the module string.
4. Lamination Installation: After the back-side connections are completed and inspected, the module strings, glass, and cut EVA, fiberglass, and backsheet are laid out in layers to prepare for lamination. A primer is applied to the glass beforehand to increase the adhesion between the glass and EVA. During installation, ensure the relative positions of the battery strings and other materials such as glass, and adjust the distance between the batteries to lay a good foundation for lamination. (Lamination layers: from bottom to top: glass, EVA, battery, EVA, fiberglass, backsheet).
5. Module Lamination: The laid-out cells are placed in a laminator. Air is removed from the module through vacuuming, and then the EVA is heated to melt, bonding the cells, glass, and backsheet together. Finally, the module is cooled and removed. The lamination process is a crucial step in module production; the lamination temperature and time depend on the properties of the EVA. When using fast-curing EVA, the lamination cycle time is approximately 25 minutes. The curing temperature is 150℃.
6. Trimming: During lamination, EVA melts and solidifies outward due to pressure, forming burrs. Therefore, these burrs should be removed after lamination is completed.
7. Framing: Similar to framing a mirror, framing the glass assembly with an aluminum frame increases its strength, further seals the battery assembly, and extends battery life. Gaps between the frame and the glass assembly are filled with silicone resin. The frame members are connected using corner keys.
8. Soldering junction box: Solder a box at the lead wires on the back of the component to facilitate the connection between the battery and other devices or batteries.
9. High-voltage test: The high-voltage test refers to applying a certain voltage between the component frame and the electrode leads to test the component's withstand voltage and insulation strength, so as to ensure that the component is not damaged under harsh natural conditions (such as lightning strikes).
10. Component Testing: The purpose of the test is to calibrate the output power of the battery, test its output characteristics, and determine the quality level of the component.
