Momentive launches SilTRUST silicone encapsulant technology for solar energy

ALBANY, USA: New transparent silicone encapsulant technology from Momentive Performance Materials Inc, a leading global provider of silicones and advanced materials, can help ensure the long-lasting performance of solar energy 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 PV modules may result in higher longer-term return on investment 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 in Cologne, Germany, April 24-26.

In the solar industry, SilTRUST encapsulant can be used to surround the fragile solar cells of the PV module with a very 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 unique technology, through a combination of optical and outstanding mechanical properties, SilTRUST silicone encapsulant materials offer module manufacturers a commercially viable way to produce crystalline silicon PV modules with a longer use life and better energy conversion efficiency.

Because silicones do not absorb ultraviolet light, more sunlight reaches the surface of the solar cell where it becomes available for conversion to electricity. The refractive index of 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 much lower module manufacturing temperatures, thus avoiding stress due to differences in thermal expansion coefficients of a module’s components. At 80°C, which is about the maximum operating temperature for a PV module, a silicone module is virtually stress free. This is one of the factors why silicones remain the material of choice for extraterrestrial photovoltaic panels that see many extreme thermal cycles, enduring severe thermal shocks during the course of a day, as satellites orbit the earth. SilTRUST encapsulant material now enables cost effective manufacturing of crystalline silicon solar modules for terrestrial purposes.

“SilTRUST silicone encapsulation of solar cells has been shown to improve the efficiency and durability of solar panels while lowering manufacturing costs,” said Dr. Alex Scholten, Global Program Leader, EcoEnergy at Momentive Performance Materials. “In tests, this encapsulant material outperformed traditional encapsulant materials in PV applications. With our project collaborators, we have also developed a lower temperature, cost-effective module manufacturing process to offer flexibility in equipment and raw materials use as well as ease and speed in processing.”

The process not only requires significantly less investment in equipment, it also operates at much lower temperatures and faster curing speeds than typically found in the manufacture of cells encapsulated using other materials.

“Innovation in encapsulant formulations and processing technology will lead to higher quality solar panels that are less expensive to make,” said Dr. Markus Putzer, Engineered Materials Technology Leader at Momentive Performance Materials. “At Momentive, we see this as a contribution towards making solar energy a competitive, reliable and sustainable source of energy.”