A solar panel is a device that converts solar energy into electrical energy. Since solar panels can be customized flexibly, small custom solar panels have been applied to many off-grid solar applications, such as solar chargers, solar attic fans, and solar LED lights etc.
Usually the solar panels we see are a complete piece of panel, but do you know what the internal structure of the solar panels is?
Small Custom Solar Panel
Here, we mainly introduce the crystal silicon solar panels that are more common on the market as an example.
The structure of crystalline silicon solar panels is usually: tempered glass / EVA / solar cell / EVA / backsheet.
Solar Panel Construction
(1) Tempered glass: Its function is to protect the main body of power generation (such as solar cells). The choice of light transmission is required:
1. The light transmittance must be high (generally 91% or more); 2. Ultra-white tempering treatment.
(2) EVA: Used to bond fixed tempered glass and solar cell. The quality of transparent EVA material directly affects the life of solar panels. EVA exposed to air is prone to aging and yellowing, thus affecting the light transmission of solar panels, so then, affecting the power generation quality of the solar panels. In addition to the quality of the EVA itself, the influence of the lamination process of the custom solar panel manufacturers is also very large. For example, if the EVA adhesiveness is not up to standard, the bonding strength of EVA and tempered glass and backing plate is insufficient, which will cause EVA early aging, thus affects solar panel’s life.
(3) Solar Cell: Solar cells are the core components of solar panels. The main function of solar cell is power generation.
(4) Back sheet: Its function is sealed, insulated and waterproof. Generally, materials such as TPT and TPE must be resistant to aging. Most solar panel manufacturers are guaranteed for 25 years. Tempered glass and aluminum alloys are generally no problem. The key is whether the back sheet and silica gel can meet the requirements.
When the solar cell is soldered, the next step is to laminate, according to the following sequence, tempered glass / EVA / solar cell / EVA / back plate, stacked, and then sent to the laminator for vacuuming, and high temperature lamination. EVA is solid at room temperature, but when EVA is exposed to high temperatures, it becomes liquid. Therefore, in the laminator, after the EVA is melted into a liquid state, the solar cell sheet and the tempered glass and the back sheet are glued together.
Just after laminating from the laminator, usually on the four sides of the solar panel, there is some excess EVA overflow, which requires a knife to cut and burr. After processing, a complete solar panel is produced.
Editor: Carrie Wong / WSL Solar