02 May 2012
Momentive Performance Materials Inc.'s new transparent silicone encapsulant technology can help ensure the long-lasting performance of solar photovoltaic (PV) modules in harsh outdoor environments, while improving the light-to-electricity conversion yield.
Greater stress-resistance, weatherability, corrosion protection and a longer life span with higher efficiency for crystalline silicon (c-Si) PV modules may result in a higher, longer-term return on investment (ROI) for solar energy projects. Momentive introduced its SilTrust transparent silicone encapsulant material in a technical paper on silicone encapsulation at the Polymers in Photovoltaics 2012 forum on 24-26 April 2012 in Cologne, Germany.
In the solar industry, the SilTrust encapsulant can be used to surround the fragile solar cells of the PV module with a flexible, stress-dissipating silicone matrix that adheres well, yet does not pass on much of the mechanical stress the cell may suffer due to harsh environmental conditions. Based on a combination of optical and outstanding mechanical properties, SilTrust silicone encapsulant materials offer module manufacturers a commercially viable way to produce c-Si PV modules with a longer use life and better energy conversion efficiency than the traditional.
Because silicones do not absorb ultraviolet (UV) light, more sunlight reaches the surface of the solar cell where it becomes available for conversion to electricity. The refractive index of the SilTrust encapsulant closely matches the refractive index of glass, reducing energy-dissipating reflection of sunlight away from the solar cell.
SilTrust encapsulant is used at low module-manufacturing temperatures, thus avoiding stress due to differences in the thermal expansion coefficients of a module's components. At 80°C (176°F), which is about the maximum operating temperature for a PV module, a silicone module is virtually stress-free. This is one of the reasons why silicones remain the material of choice for extraterrestrial PV panels that see many extreme thermal cycles, enduring severe thermal shocks during the course of a day, as satellites orbit the earth. The SilTrust encapsulant material enables cost-effective manufacturing of c-Si solar modules for terrestrial purposes.