Improvement of Laser Contact Opening in Bifacial PERC Solar Cells by Optimizing the Dashed Pattern

The laser contact opening in passivated emitter and rear cell (PERC) is essential for establishing contact between silicon and aluminum. On bifacial PERC solar cells, dashed patterns are commonly employed as an alternative to continuous openings to mitigate excessive losses associated with passivation film removal. In this work, we investigate the optimization of dashed patterns in detail. First, under the condition of the same 50% opening ratio, the optimal total length of segments is determined to be 1.2 mm. Subsequently, testing various opening ratio patterns on wafers with different resistivities reveals that low-resistivity wafers are better suited for low opening ratio patterns. Finally, simulation analyses using Quokka2 software assess the variations in power loss associated with different opening patterns, the simulation results align with those of experiments. This work provides a guidance for the rear-side laser opening pattern design of bifacial PERC solar cells.