Lifetime prediction of polymeric materials in PV module under continuously varying environments based on damage summation approach

[Display omitted] •The method to predict lifetime of PV component operating continuously varying environment is proposed.•Empirical life model is employed based on accelerated life test.•Damage accumulation in both operating and accelerated life test conditions are calculated.•The lifetime in operating conditions can be inferred based on calculated damage.•Accelerated life tests were conducted on different types of backsheets. We propose an approach for predicting the service lifetime of polymeric materials in photovoltaic (PV) module. This approach is particularly effective for devices operating under continuously varying environments, which make it difficult to establish an adequate correlation between laboratory testing conditions and field operating conditions. To account for these factors, the damage summation method is proposed, which calculates and compares the accumulated damages caused by stresses based on real weather data and laboratory testing conditions. In order to apply this method, an empirical accelerated life model for the backsheet, which is typical polymeric material and used as the packaging material in the module, is developed by conducting an accelerated life test (ALT). The developed model quantitatively demonstrates how environmental stresses impact the performance degradation of the backsheet. By incorporating the environmental conditions into the developed model, the accumulated damages to the backsheet under both experimental laboratory testing and real operating weather conditions are calculated. Finally, the lifetime under operating conditions can be inferred by comparing both accumulated damages.