Solutia Inc. (NYSE: SOA) , the only global one-stop source for EVA, TPU, and PVB based solar encapsulants, announces an advanced encapsulant designed to prevent corrosion in solar cells. The new encapsulant, branded as Saflex® PS41 PVB, also inhibits discoloration, making it an ideal module encapsulant for use in building integrated photovoltaics (BIPV).
"Metal electromigration, has long been a reliability concern in the electronics industry," comments Francois Koran, Solutia Photovoltaic Development Manager. "It's highly problematic for the photovoltaic market as well because of panel discoloration."
Metal electromigration is an electrochemical process where metal (e.g., silver), in contact with an insulating material in a humid environment and under an applied electric field, migrates into the insulating material. The net result of metal migration can be either a reduction in insulation resistance or a short circuit which may lead to circuit failure. For solar applications, module manufacturers are concerned that metal migration will affect the long term performance of solar modules which have life expectancies of twenty to thirty years.
Modules designed for use in architectural applications (BIPV) are particularly sensitive to metal migration as any discoloration in the solar module is a critical concern for architects, designers, and module manufacturers. Discoloration in this case would undermine the aesthetic appearance of a building and bring to question the reliability and performance of the solar modules.
Saflex PS41 is the first solar PVB encapsulant designed specifically to protect against metal migration and maintain the original aesthetics of the solar module. The key to this patent-pending technology is the ability of this encapsulant to prevent electromigration when in contact with certain metals such as silver, nickel, and vanadium. It is often the presence of these oxides that leads to module discoloration.
Silver, for example, is a widely used metal in solar cell stacks and conductive adhesives. Elemental analysis shows reduced silver levels in Saflex PS41 compared to other standard encapsulants. "In terms of performance reliability, Saflex PS41 performs exceptionally well," continues Koran. "As for discoloration, the module samples with PS41 compared to standard encapsulants speak for themselves." Saflex PS41 is IEC certified, RoHS approved and UL recognized.