Applications of parallel dispensing in PV metallization

Abstract

This study provides a summary of latest solar cell results achieved with parallel dispensing equipment that will be commercialized by a Fraunhofer ISE spin-off (HighLine Technology GmbH) within the next year. The goal was to show alternative process routes for the PV back-end, some of them without any laser or screen printing steps involved. On the front surface of conventional PERC solar cells, an efficiency of ηmax = 21.9% was reached applying 150 parallel dispensed contacts with a finger width of only wf = 17 µm but still excellent contacting behavior. Successful applications of fire through Al pastes were demonstrated on bifacial p-PERC and n-PERT samplings. On the latter, the Voc gap to a dispensed AgAl reference was only ΔVoc = −1.7mV which shows that a potential replacement of Ag by Al is possible once a better conductivity of Al-FT pastes is achieved. On HJT solar cells, dispensed Ag and AgCu contacts were demonstrated by applying commercial available low temperature screen printing pastes with the former outperforming the screen printed reference by Δη = +0.3%abs reaching ηmax = 22.2% at a substantial decrease of Ag paste laydown.