Impact of reverse breakdown in shaded silicon solar cells on module level: Simulation and experiment

In this work, we present a method to predict temperature fields of cells assembled into solar modules under partial shading conditions prior to module fabrication. Our approach consists of three steps; (i) measure the power dissipation spatially resolved on cell level using lock-in thermography, (ii) determine the operating points of the partially shaded cell and module for different shading scenarios and (iii) separate the totally dissipated power into contributions by the cell's local reverse behaviour in the dark and the impact of illumination. Using the results of these three steps as input parameters, we simulate stationary temperature fields using a three dimensional thermal simulation in order to evaluate the potential of a damage due to hot spots on the solar cell. We achieved good agreement between simulated temperature fields and experimental infrared images of a test module for different shading scenarios. Furthermore, we gain depth-resolved information which is not accessible during hot spot testing.