Automatic Detection of Inactive Solar Cell Cracks in Electroluminescence Images

Inactive solar cell regions resulted from their disconnection from the electrical circuit of the cell are considered to most severe type of solar cell cracks, causing the most power loss. In this work, we propose an algorithm for automatic determination of the electroluminescence (EL) signal threshold level corresponding these inactive solar cell regions. The resulting threshold enables automatic quantification of the cracked region size and estimation of the risk of power loss in the module. We tested the algorithm for detecting inactive cell areas in standard mono and mc-Si, showing the influence of current bias level and camera exposure time on the detection. Last, we examined the correlation between the size of the detected solar cell cracks and the power loss of the module.