Reliability assessment on PV backsheets with and without considering spectral UV albedo effects: A theoretical comparison

Abstract

Trustworthy evaluation on the long-term reliability of PV backsheets depends largely on the estimation of ultraviolet (UV) damage from the ground reflection; however, current use of total UV irradiance can hardly provide precise estimation due to the spectral UV albedo of grounding materials and spectral sensitivity of backsheet degradation. In this work, effects of spectral UV albedo on the estimation of UV damage were evaluated theoretically through the combinations of 35 types of grounding materials and 4 types of common backsheet materials, including polypropylene (PP), polyethylene terephthalate (PET), polycarbonate (PC) and polyamide (PA). The results showed that, without considering the spectral reflectivity, overestimation of the UV damage for PV backsheets can happen. This work can provide the critical basis for developing more precise lifetime prediction model and designing more reliable accelerated aging tests.