Aging behavior and degradation of different backsheets used in the field under various climates in China

Abstract The performance of photovoltaic (PV) modules and their component materials under outdoor environmental stresses is the most important indicator of reliability, durability, and safety of PV modules throughout their service life. In this study, fielded modules with polyamide-based back-sheets (PA/PA/PA) and Tedlar PVF-based backsheets (PVF/PET/PVF) (TPT) from arid and subtropical climates in China were collected for comparison analysis. PA and PVF back-sheet samples were removed from the fielded modules. The weatherability of the airside layer of two different types of photovoltaic back-sheets has been compared and studied. Chemical composition, mechanical performance, surface morphology and optical discoloration of these back-sheet samples were evaluated to understand the degradation of back-sheet materials in fielded modules. By a series of measurements, significant differences were found in the durability between them.