Solar cell encapsulation film material introduction & silane recommendation

Solar cell encapsulation film material introduction & silane recommendation

Solar cell encapsulation film materials mainly include EVA film, POE film, co-extruded EPE film and other types, and different materials are suitable for different scenarios. ‌

EVA (Ethylene-Vinyl Acetate Copolymer) Film

A functional film based on ethylene/vinyl acetate copolymer, refined by adding cross-linking agent, coupling agent and anti-ultraviolet agent. This film has high light transmittance, excellent resistance to ultraviolet heat and yellowing, anti-snail pattern and good adhesion. However, its insufficient reflectivity and high water permeability may cause potential potential induced degradation (PID) phenomenon, which in turn affects the power of battery components.

POE (Polyolefin elastomer) film

A metallocene polyethylene elastomer polymerized by ethylene and 1-hexene or 1-octene under a metallocene catalytic system is widely used in the encapsulation of photovoltaic modules. Compared with EVA, POE has a more stable molecular structure and almost no gas release. At the same time, it also exhibits higher volume resistivity, thermal stability and UV aging resistance. It is particularly worth mentioning that the water vapor permeability of POE is only about 1/8 of that of EVA and silica gel. This feature enables it to more effectively block water vapor, protect solar cells, and reduce component power attenuation. However, POE also has some shortcomings, such as its glass bonding ability is not as good as EVA, which may lead to interface failure, and the lamination time is long, the process window is narrow, and it is easy to produce bubbles during the lamination process, affecting the appearance. POE film still has a wide range of application prospects in the packaging of single crystal emitters and rear passivated cells (PERC) bifacial, N-type battery components.

EPE film

This innovative "EVA-POE-EVA" three-layer composite structure film is carefully compounded and modified by EVA material and POE material, and then carefully manufactured by co-extrusion process, and finally presents the characteristics of a co-extruded POE film. In terms of material composition, it cleverly combines 60% POE resin and 40% EVA resin, which not only absorbs the advantages of the two materials, but also avoids their respective shortcomings.

In terms of application, EVA film is mainly suitable for P-type monofacial cells, while POE/EPE film is more suitable for P-type bifacial cells and N-type cells. EPE film is particularly suitable for the encapsulation of PERC bifacial double-glass, N-type bifacial double-glass and other photovoltaic modules with high weather resistance requirements.