Establishing the long term moisture barrier performance of the edge seal from accelerated testing

In this work a novel and relatively inexpensive test technique is developed for characterizing moisture barrier performance of the edge seal in PV modules in a manner that is decoupled from other components of the PV module. A theoretical framework is developed to conjecture appropriate equations and functional forms for moisture breakthrough time in accelerated tests as well as in the field for an edge seal with desiccant embedded in it. Results from accelerated testing are shown to fit the proposed functional forms under various conditions thereby validating the theoretical framework. These equations and functional forms enable the prediction of long term moisture barrier performance of the edge seal using historical meteorological data (TMY data) in conjunction with results from accelerated tests. In the specific case of edge seal tested on certain MiaSole glass-glass modules these results establish that the edge seal considered is sufficient to prevent moisture ingress in the module, beyond the intended service life of the module, even for the most aggressive environmental conditions evaluated in this study. Further this study identifies paths to extend this work to the more complex structure involved in building CIGS based flexible products.