Development of Integral Coating for Solar Cell Modules

摘要

A process has been developed by which integral solar cell covers (ISCC's) can be applied directly to the front surface of solar cell modules. The covers are a codeposited mixture of silica and alumina. The tensile-stressed alumina serves to compensate for the compressive stress of the silica. The process by which these covers are applied is Plasma Activated Chemical Vapor Deposition (PACVD) which is a low-temperature CVD process (145 C). The process utilizes the OCLI-proprietary Plasma Activated Source (PAS) to generate activated oxygen species to simultaneously oxidize silane and trimethylaluminum (TMA) to form silica and alumina on the substrate surface. By adjusting the reactant flow rates, the codeposited cover stress can be adjusted to quite low stress levels, typically zero to three kpsi. Besides serving to protect then junction of the solar cells from particle damage, the cover may also serve as an electrical insulator in high-voltage array applications. Tests as to the effectiveness of the integral cover as an insulator will be performed in the future by the Air Force. A significant advantage of ISCC's over conventional covers is that the minimum degradation temperature of the assembly is significantly increased by elimination of the adhesive used to bond the conventional covers. In this project, four ISCC modules were delivered: two for the Interaction Measurements Payload for Shuttle (IMPS)/Photovoltaic Array Space Power (PASP) project and two for a Living Plume Shield III (LIPS III) project.