Hot Spot Susceptibility and Testing of PV Modules

To probe the sensitivity for localized heating of commercial amorphous silicon and crystalline modules, several intrusive and nonintrusive experiments were performed. In the intrusive experiments, each cell in several commercial amorphous silicon modules was evaluated separately and in groups for localized heating effects. Damage in amorphous silicon modules occcurred under reverse-bias conditions in the dark above a 5-20 mAcm^-2 cell current density at the interconnection between cells. Shading can cause a larger temperature rise than current mismatch. For the monolithic amorphous silicon modules investigated, the current mismatch between each cell was substantial, but the temperature rise was negligible because of the rather low shunt resistance.