Simulation of Large-Area Silicon Solar Cells1

Twoand three-dimensional numerical modelling has recently become an important tool for the characterisation and optimisation of high-efficiency silicon solar cells. In the past, however, such modelling could only be applied to small sections of the cells. While such limited simulation domains are sufficient for the analysis of bulk and surface properties, the analysis and optimisation of effects like the losses resulting from the resistance of the metal contact grid require a model of the full cell and need to include edge effects. In this paper, we present an approach which combines multi-dimensional device simulation with circuit simulation to produce an accurate model of a full-sized high-efficiency solar cell. We demonstrate the power of this approach by presenting the results of an investigation of the series resistance of “passivated emitter, rear locally diffused” (PERL) silicon solar cells. The insights gained in that study triggered a small design change in the contact geometry, which managed to reduce resistive losses by more than half and contributed to a new efficiency world record.