The solar glass, cells, and backsheet are held together by the voltaic encapsulation film. One of the most important things is the module cells’ protection.
The encapsulating film must possess a variety of qualities as a component, including strong weather resistance, optical qualities, moisture barrier, and electrical qualities. The encapsulating film material’s inherent features are vital to the fulfillment of these crucial attributes.
Both EVA and POE have benefits and drawbacks in the realm of photovoltaics. EVA has excellent bonding performance with glass and backplane, is less expensive, simple to produce, resistant to storage, and has a quick cross-linking speed. PID resistance and high material qualities are the key benefits of POE. Outstanding features include low temperature resistance, high resistivity, a high water vapor barrier rate, and resistance to yellowing.
The hydrolysis of vinyl acetate under light, oxygen, heat, and humid conditions results in acetic acid, which corrodes solder ribbons and cell surfaces. This is one of the drawbacks of EVA. Additionally, it combines with the Na in the glass to produce a significant number of freely moving Na ions, which attenuates power. In addition, EVA is susceptible to yellowing in bright and hot settings, which reduces light transmittance and increases the component’s overall power loss.
One of POE’s drawbacks is its low polarity. The polar additive solvent precipitates on the film surface during the manufacturing process, making the surface smooth and simple to move; the processing is challenging, and the film lip is easy to hang items; POE particles are more costly overall than EVA. The application fraction of POE particles in film particles is expected to increase during the next several years, mostly due to the following factors:
1. N-type battery: The doped boron-oxygen complex of P-type batteries in the silicon wafer will cause the potential to decay faster. N-type batteries are mixed with scale and have better anti-attenuation performance. The current photoelectric conversion efficiency of P-type batteries is close to the upper limit of 24.5%, whereas the upper limit of N-type battery conversion efficiency is higher. N-type batteries have a more sensitive PID impact on the surface that receives light. After the light is restored, N-type components with significant PID attenuation will likewise result in permanent damage. Simultaneously, the backplane exhibits inadequate water vapor barrier characteristics when N-type batteries are packed with a single piece of glass.As a result, selecting POE film for packaging can decrease the module’s total water vapor transfer rate and increase its usable life. As a result, encouraging N-type batteries may result in a rise in POE use.
2. Large-scale battery power: Different battery component types have seen considerable power improvements and an increase in heat generation in recent years. The temperature greatly affects the packing materials since it will have a bigger effect on the battery’s peak power, open circuit voltage, and other electrical characteristics. The standards for electrical performance are rising steadily.
3. The number of double-glass components is rising while cover glass is decreasing: CPIA data indicates that there are now three different glass thickness levels: <2.5mm, 2.8mm, and 3.2mm. Of these, glass cover plates with a thickness of <2.5mm make up 32% of the market, and by 2025, that percentage is predicted to rise to almost 50%. Glass thinning will result in ever-higher performance standards for packaging materials. POE is robust and mechanically strong.
POE and EVA resins are co-extrusion processed to create the multi-layer EPE film. Typically, it has one layer of POE and two layers of EVA. EPE film is a cost-performance compromise that partially accounts for the cost advantage of EVA film and the strong performance of POE film. EPE film will take up some market space if there is a short-term shortage of POE resin.
