In the past few years, a serious failure mode in the performance of photo voltaic (PV) panels has been observed in many fielded systems. A slow but significant decrease in conversion efficiency was associated with panels operating at a high negative potential (voltage) relative to ground, and this phenomenon was named potential-induced degradation (PID).
After further study, it was noted that the degradation was most pronounced for panels simultaneously subjected to a large negative potential while under conditions of high humidity and elevated temperatures. Subsequent analysis showed that the deterioration was due to small leakage currents from grounded conductors, such as the metal panel frames, which eventually led to the build-up of positive ions in the top layer of the photo voltaic cells. These ions created electric fields within the cells in opposition to the internal fields that had been intentionally engineered into these structures to facilitate electricity production. As a result, the conversion efficiency of the affected cells was degraded.
Read on and find out the possible solutions to potential-induced degradation!