Accurate extraction of the series resistance of aluminum local back surface field silicon wafer solar cells

Aluminum local back surface field (Al-LBSF) silicon wafer solar cells are currently intensively investigated in the photovoltaic community and are expected to enter mass production in the near future. In this work we show that this solar cell architecture can pose significant challenges in the determination of the series resistance at the maximum power point. We also show that some of the traditional methods for extracting the series resistance of these cells result in a severe underestimation, due to injection dependent saturation current densities. By using a combination of electro- and photo-luminescence images, we demonstrate that the series resistance of Al-LBSF solar cells can be accurately determined.