In the production of solar panels, photovoltaic (PV) films like Expanded Polyethylene (EPE), Ethylene-Vinyl Acetate (EVA), and Polyolefin Elastomer (POE) are essential. The classification and properties of these three widely used PV film materials are thoroughly examined in this article. We may learn more about their applicability for various photovoltaic demands by looking at their fundamental characteristics, material composition, preparation techniques, physical attributes, weather resistance, transparency, and advantages and disadvantages in PV applications.
Fundamental Qualities
Thermoplastic polymers POE, EVA, and EPE are frequently utilized as encapsulation films in photovoltaic modules. POE is an elastomer based on polyolefins that combines the elastic qualities of rubber with the flexibility of polyethylene. EVA is a flexible and transparent copolymer made of ethylene and vinyl acetate. Expanded polyethylene foam with closed cells, or EPE, is renowned for being lightweight and soft. These materials are chosen in accordance with certain specifications including electrical insulation, adhesion, and durability.
Material Make-Up and Methods of Preparation
POE films are usually made of a blend of polyethylene with elastomeric additives, including styrene-butadiene-styrene (SBS) block copolymers or ethylene-propylene-diene monomer (EPDM) rubber. The film is made using extrusion and melt blending, among other techniques. EVA films are made of vinyl acetate and ethylene monomers; the amount of vinyl acetate in the film determines its characteristics. Copolymerization techniques, such as high-pressure autoclaving and tubular procedures, are used to create EVA films. Low-density polyethylene (LDPE) is expanded through the use of chemical or physical foaming agents, followed by extrusion, to create EPE films.
Physical Characteristics
POE films have good mechanical strength, high elongation at break, and outstanding flexibility. They can function in a wide temperature range and keep their qualities even under harsh circumstances. EVA films have outstanding adherence to solar cell materials and glass, together with exceptional flexibility and high optical transparency. When compared to POE films, they usually have a lower melting temperature. EPE films have excellent thermal insulating qualities, a high impact resistance, and a low density. They give PV modules protection and cushioning.
Transparency and Weather Resistance
POE films show outstanding resistance to moisture, temperature changes, and UV light. Even after extended exposure to outside environments, they keep their mechanical characteristics and transparency. Although EVA films have strong UV protection, manufacturing and formulation techniques may have an impact on their long-term performance. EPE films can tolerate a range of environmental conditions and offer moderate weather resistance. Because of their closed-cell structure, EPE films have lower transparency than POE and EVA films, which have good optical clarity and efficient light transmission to the solar cells.
PV Applications’ Benefits and Drawbacks
POE films are suited for a variety of PV applications due to their exceptional mechanical strength, superior flexibility, and resilience to weather. They enhance the efficiency of photovoltaic conversion by effectively capturing light. Because of their excellent optical transparency, adhesive qualities, and processability, EVA films are frequently utilized in PV modules. On the other hand, their propensity for yellowing and long-term durability may provide certain restrictions. Because EPE films are lightweight, impact resistant, and cushioning, they are used in protective layers and module packaging. However, light loss in PV modules could result from their reduced transparency.
Different PV film materials, including as POE, EVA, and EPE, each have special qualities and are appropriate for particular uses. POE films provide exceptional mechanical and weather resilience. EVA films have good adhesive and transparency qualities. Impact resistance and lightweight qualities are provided by EPE films. When choosing the best PV film material for a given solar application, one can make an informed decision by being aware of the categorization, material composition, physical characteristics, weather resistance, and transparency of these films.
