IMPLEMENTATION AND OPTIMIZATION OF AN INDUSTRIAL MC-SI PERC PROCESS FOR MASS PRODUCTION

摘要

Rear passivated c-Si solar cells with local contacts (PERC - Passivated Emitter and Rear Cell) have been shown to be an evolutionary next generation cell type that allows an efficiency gain of up to 1 % (abs., mc-Si material) compared to a conventional Al-BSF cell structure and that is suitable to be implemented into existing industrial c-Si production lines. Several institutes as well as cell and equipment manufactures are currently implementing PERC processes into mass production both for CZ and mc Silicon cells. This paper reports about the upgrade of an industrial Al-BSF mc-Si cell production line to three busbar mc PERC cells and the implementation and optimization all relevant process steps on industrial equipment. Process adaptations include single sided rear polishing, ICP-PE CVD AlOxSiNy rear passivation, ps and ns laser contact opening as well as adapted screen printing and firing processes. A stable efficiency gain of up to 1.0 % (abs.) could be achieved compared to the Al-BSF baseline process for mc-Si wafer material of different quality and origin and for different printing pastes. Further possible improvements are discussed. The mc-Si p type PERC solar cells have been assembled into glass/glass modules and tested for degradation in the laboratory and in a real field test under outdoor conditions in Lithuanian climate.