PVMaT Improvements in the BP Solarex Photovoltaic Module Manufacturing Technology: Annual Report, May 5, 1999 - June 15, 2000

This is the annual report for a 3-year PV program to continue to advance BP Solarex photovoltaic manufacturing technologies to design and implement a process that produces polycrystalline silicon PV modules that can be sold profitably for $2.00 per peak watt or less, and which increases the production capacity of the Frederick plant to at least 25 megawatts per year. The accomplishments discussed in this report include: (1) developed processes to produce high-purity SiF4 gas from a number of available commercial sources; (2) designed and implemented a new control system for casting; (3) verified relationship between higher minority-carrier lifetime in cast Si and cell efficiency; tracking material quality by measuring minority-carrier lifetime for each production casting; (4) reduced the wire-saw pitch to 450 microns with no loss in downstream yield; (5) demonstrated 8% improvement in average cell power on pre-production trial lots using PECVD silicon nitride; (6) developed a new EVA formation and demonstrated a 6-minute process to achieve adequate cure of PV modules in standard lamination equipment; (7) designed, purchased, and installed a new automated assembly line for large-area modules; and (8) implemented a factory-wide data collection and tracking system; production volumes and performance parameters are now monitored in real time through the local area network