Evolutionary algorithm optimizes screen design for solar cell metallization

Today’s PV production chain heavily relies on screen printing as the predominant metallization process because of its robust production capabilities. However, the continuous demand to further increase throughput rates while at the same time decreasing printed structure sizes is going to create fundamental challenges in the upcoming years. In order to address this problem, robust fine-line screens at competitive production costs need to be developed. Throughout this study, we present an optimization of screen architectures by utilizing an evolutionary algorithm. Individual screen architectures are defined by genes that represent industrial manufacturing parameters. Our algorithm then solves for the optimal trade-off between printability of a screen, its mechanical stability and optimal mesh tension to ensure sufficient snap-off mechanics. Further, a computational fluid dynamics simulation is performed to find the optimal thickness of the corresponding emulsion layer in respect to the underlying optimized mesh architecture. Our results predict mesh configurations with mesh counts up to MC = 1268 1/inch and wire diameters down to d = 6.7 µm in order to enable fine-line printing below 10 µm.