Photovoltaic encapsulant film generally refers to photovoltaic EVA encapsulant film. It plays a crucial role in the encapsulation process of photovoltaic modules and is one of the essential materials used in photovoltaic modules. The encapsulant film bonds photovoltaic cells, photovoltaic glass, and backsheets, primarily protecting the cells and encapsulating them into a photovoltaic module capable of outputting direct current.
I. Types of Photovoltaic Encapsulant Film
There are many types of adhesive films, each with different characteristics and applicable scenarios. Currently, the types of adhesive films on the market include transparent EVA film, white EVA film, POE film, and EPE film.
1. Transparent EVA film: Used for photovoltaic module encapsulation. It features high resistance to PID, high light transmittance, resistance to UV and damp heat yellowing, resistance to snail trails, and good adhesion to glass and backsheets. Its disadvantages include poor reflectivity, high water permeability, and susceptibility to PID phenomena. It is widely used for encapsulation of the upper layer of single/double-glass modules.
2. White EVA film: Used for encapsulating the underside of photovoltaic module cells. With high reflectivity, white EVA film allows sunlight to be reflected a second time onto the cell surface, improving the power generation efficiency of the solar module. It can meet the high-yield encapsulation requirements of single-glass modules, double-glass modules, and thin-film modules, but the price is relatively high.
3. POE film: Made from POE resin, it is used in single-product PERC bifacial and N-type cell modules, especially in double-glass modules of the above high-efficiency cells, with higher water vapor barrier rate, better weather resistance and stronger anti-PID performance.
4. Co-extruded POE film: Also known as EPE film, it features an "EVA-POE-EVA" structure and combines the anti-PID properties of POE with the low cost of EVA. It is suitable for encapsulating PERC double-sided double-glass, N-type double-sided double-glass, and other photovoltaic modules with high weather resistance requirements. It possesses both the high water resistance and high anti-PID properties of POE material, as well as the high yield lamination process characteristics of EVA double-glass modules, and is less affected by the relative shortage of POE resin.
II. Advantages of Photovoltaic Encapsulant Film
1. High transparency and high adhesion make it suitable for various interfaces, including glass, metal and plastics such as PET.
2. Good durability can resist high temperature, moisture, ultraviolet rays, etc.
3. Easy to store. When stored at room temperature, the adhesive strength of EVA is not affected by humidity or absorbent film.
4. Compared to PVB, it has a stronger sound insulation effect, especially for high-frequency sound effects.
5. Low melting point, easy to flow, suitable for various glass lamination processes, such as patterned glass, tempered glass, curved glass, etc.
