PV module durability testing under high voltage biased damp heat conditions

Ten commercially available photovoltaic module technologies were selected for this study including five thin-film technologies and five silicon wafer based technologies. These modules were subjected to accelerated ageing tests in a dark climate chamber under conditions of 85C and 85% relative humidity and electrical bias for 650 hours. The bias voltage ± 1000 V DC was applied between the active circuit of each module and module frame to study the impact of electrical bias on PV module durability under hot and humid conditions. Module performance assessed with a Class A solar simulator under standard testing conditions (STC) showed the biased stressing condition in damp heat test could significantly degrade electrical performance and cause various defects such as delamination, glass surface deterioration, frame corrosion, and metal grid discoloration, depending on module type and bias polarity.