Automated array assembly. Quarterly report No. 5. [Cost analysis and factory design

Abstract

During this quarter, an interim 1982 factory was designed for the large-scale production of silicon solar cell array modules. The boundary conditions for this design are the use of Czochralski silicon crystals and $25/kg polycrystalline silicon. The objective is a large-scale production facility to meet an intermediate ERDA cost goal of $2.00/W in 1982. The approach was to first consider a panel design which could be expected to have a 20-year life and would also meet the JPL specification on mechanical, electrical, and environmental stability. Attention was then directed to a cost analysis of the production of the elements comprising this panel. Since it was expected that wafer production would comprise a major fraction of the cost, several cost reduction schemes were considered for the Czochralski pulling and sawing of the wafers. A solar-cell processing sequence was selected on the basis of our previous cost studies and the projected availability of production equipment by 1982. These criteria resulted in the selection of POCl/sub 3/ gaseous diffusion for junction formation, thick-film Ag screen-printed metallization, spray-on antireflection (AR) coating, and solder reflow interconnect technology. The economic study was made by computer analysis of the cost elements of these process sequences at production levels ranging from 3 to 100 MW/yr. With the results of this study, a 30-MW/yr factory was designed, and a preliminary floor plan layout is given. A manufacturing cost of $2.01/W is projected and, including factory overhead and profit, a selling price of $2.27/W is projected.