Investigating the impact of edge passivation on shingle solar modules

Abstract

This work deals with solar modules made from rectangular-shaped solar cell strips, so-called shingles, that are interconnected by overlapping one with another. For the fabrication of such modules, host solar cells are cut into several shingles resulting in unpassivated shingle cell edges and relevant recombination losses. As discussed in this work based on simulations, quantifying these losses on module level is not straightforward and is ideally done by referring to the pseudo fill factor pFF. In this context, it is shown that by passivating the cut edges of the shingles by depositing a dielectric layer, a significant pFF increase can be achieved both on shingle as well as on module level. Considering the highest respective pFF value found for modules with and without edge passivation, an increase of ΔpFF = 0.5%abs is reached. At the same time, no significant compromise of the interconnection quality is observed. These results are obtained for monofacial passivated emitter and rear cell (PERC) shingles. In short, this work is the first comprehensive analysis of experimental data on module level in the context of edge passivation. It demonstrates that the deposition of a dielectric passivation layer at the shingle's edges can boost pFF of shingle solar modules, while the current transit between the busbars of jointed shingles is not significantly hindered.