Photovoltaic reliability model development and validation

The 3D simulation of moisture ingress into a photovoltaic module was performed in FlexPDE, employing a finite element approach with restriction to bulk Fickian diffusion to determine the Time-To-Saturation (TTS) for moisture for a given module construction and steady state environmental conditions. The TTS, characteristics of the module and environmental conditions were used to fit the normalized efficiency results obtained from accelerated and outdoor testing using JMP^¿ statistical software. The fit was well behaved and statistically significant parametric relationships were obtained. These relationships were then used to predict the normalized efficiency over time for various module constructions and environmental exposures. This unique approach has the potential to significantly reduce the time and effort for reliability determination of new photovoltaic module designs.