Accelerated Test Method of Environment-Induced PID for Encapsulation Materials of PV Modules

36th European Photovoltaic Solar Energy Conference and Exhibition; 50-53
Whether solar panels installed in the coastal area would suffer more severe PID phenomenon due to the salt spray environment or not was one of controversial debate topics recently. The sequence tests taken in past studies had not found decisive evidence to exclude or confirm the impact of external ions on PID effect. In view of this, the epoxy substrate covering on the special cell-scale module-like specimen was prepared to simulate the source of impurities in the coastal environment during PID test. Significant change in shunting degradation behavior could be observed on solar cell with Epoxy/Backsheet/EVA/Cell stacking sequence, in contrast, no obvious PID characteristic change was noticed for specimen with Epoxy/Glass/EVA/Cell structure. Furthermore, deeper analysis on the different operating temperatures and types of backsheet effect on the environmental-induced PID behavior of PV backsheets were also carried out based on the previous mentioned-notices. Results of the former experiment showed that the impurities in the epoxy could penetrate into the solar cell through the backsheet material rather than the front glass and experimental results of the later showed that thermal stability of PV backsheet at operating temperatures of testing system could dominate the degree of severity on PID behavior. Moreover, the experimental design also provided a new environmental impurities induced PID verification method.