A Settling Time Model for Testing Potential Induced Degradation of Solar Cells

In recent years, a barren degradation phenomenon of solar cells in large photovoltaic fields called potential induced degradation (PID) has been intensively investigated and discussed. PID is characterized by the power attenuation under high voltage stress between glass and solar cells through encapsulates. It will cause serious solar module power loss when the terminal voltage is applied on solar modules at outdoor field. For PID testing at solar-cell level, a quick and direct process method is required. In this study, a settling time model is applied for data analysis with an experimental data by a PID tester at solar-cell level to shorten the PID testing time. A settling time model is built up by the trend of measured data of the PID tester process. According the solar cell degradation settling time model, a threshold value is found at the settling time to predict PID or not on solar cell level. The experiment results show that the average test period is only 14.2 h and the hit rate is 94.2% for PID prediction. The proposed method is an efficient approach for reducing PID phenomenon in working field.