Towards Validation of Advanced Accelerated Stress Testing Protocols through Failure Analysis and Materials Characterization

As the lifetime of photovoltaic modules increases toward the goal of 50 years, accelerated stress testing is critical to assessing the viability of newer, improved, and often cheaper materials in the field. However, the validation of accelerated testing to reproduce field failure has remained elusive. The recent developments of more advanced stress testing protocols utilizing sequential and combined stressors have provided another opportunity for validation. Using a suite of mechanical, chemical, and structural characterization methods we report the development of our approach using a known bad backsheet 'AAA.' We then apply this approach to PVDF-based backsheets to further confirm the generalizability of this approach. The outcome of this work is two-fold: (1) validation of advanced accelerated testing protocols which will enable the prediction of field failures in new materials, and (2) deeper insights into the degradation mechanisms observed through the extensive characterization allowing for improved materials engineering and development.