Development of Accelerated Test Sequences to Assess Long Term Durability of PV Modules
William J. Gambogi1, Bao-Ling Yu1, Thomas Felder1, Steven W. MacMaster1, Kaushik Roy Choudhury1, Jared Tracy1, Nancy H. Phillips1, Hongjie Hu2
1E. I. du Pont de Nemours and Company, Wilmington, DE, United States
/2DuPont (China) Research& Development and Management Co., Ltd, Shanghai, China

With the introduction of new materials, processes and structures for PV modules, the assessment of module durability to the multiple stresses in the outdoor environment has become a critical part of new product evaluation.  We have developed test methodologies which evaluate the durability of PV modules to temperature, humidity, UV from the front and back of the module, and mechanical stresses related to temperature cycles and snow/wind loads.  Test sequences have been developed to reduce the overall test timing and evaluate new module structures including bifacial modules.  These tests are predictive of backsheet outer layer failure, backsheet inner layer and encapsulant delamination.  Total test time is reduced from 8.2 months to < 5 months.