Cast polycrystalline silicon photovoltaic module manufacturing technology improvements. Semiannual technical report, 1 January 1996--30 June 1996

摘要

Two specific objectives of Solarex's program are to reduce the manufacturing cost for polycrystalline silicon photovoltaic modules to less than $1.20/watt and to increase the manufacturing capacity by a factor of three. This report highlights accomplishments during the period of January 1 through June 30, 1996. Accomplishments include: began the conversion of production casting stations to increase ingot size; operated the wire saw in a production mode with higher yields and lower costs than achieved on the ID saws; developed and qualified a new wire guide coating material that doubles the wire guide lifetime and produces significantly less scatter in wafer thickness; completed a third pilot run of the cost-effective Al paste back-surface-field (BSF) process, verifying a 5% increase in cell efficiency and demonstrating the ability to process and handle the BSF paste cells; completed environmental qualification of modules using cells produced by an all-print metallization process; optimized the design of the 15.2-cm by 15.2-cm polycrystalline silicon solar cells; demonstrated the application of a high-efficiency process in making 15.2-cm by 15.2-cm solar cells; demonstrated that cell efficiency increases with decreasing wafer thickness for the Al paste BSF cells; qualified a vendor-supplied Tedlar/ethylene vinyl acetate (EVA) laminate to replace the combination of separate sheets of EVA and Tedlar backsheet; demonstrated the operation of a prototype unit to trim/lead attach/test modules; and demonstrated the operation of a wafer pull-down system for cassetting wet wafers.