Prospects and theoretical investigation of edge isolation technology in multi-cut TOPCon solar cells

Multi-cut cell technology is an effective approach to enhance photovoltaic (PV) module power, but the exposed edge significantly limits cut-cell performance due to increased perimeter-to-area ratios, i.e., more severe edge recombination. Currently, laser-assisted edge isolation (LAEI) has been proven that effectively suppresses edge recombination in half-cut cells. Here, a 3D multi-cut tunnel oxide passivated contact (TOPCon) cell model was developed in Quokka3 to systematically investigate the mechanisms and potential of LAEI. Simulations reveal that, considering only edge recombination, the optimal isolation widths are 250 μm for quarter-O (outer) cells and 200 μm for quarter-I (inner) cells, yielding theoretical efficiency gains of 0.47% and 0.80% (absolute), respectively. Furthermore, a synergistic strategy combining LAEI with edge passivation is proposed. By simultaneously suppressing recombination in both the space-charge and quasi-neutral regions, the combined approach delivers greater module power gains than either technique alone. Notably, simulations show that edge-isolated cells relax the passivation requirements for edge passivation, offering significant advantages for large-scale manufacturing and throughput. More importantly, the carrier recombination and transport mechanisms at cut edge are systematically analyzed to elucidate the underlying physics. Overall, this work provides a comprehensive optimization and mechanistic understanding of edge isolation in multi-cut cells, offering strong guidance for its industrial implementation.