Effect of ultraviolet aging of backsheet on electrical performance of silicon photovoltaic module

Abstract

Photovoltaic (PV) backsheets protect solar cells from corrosion, moisture intrusion, and environmental pollution, and they also reflect light to be reabsorbed by solar cells. Previous studies have confirmed that PV backsheet materials can affect the performance of PV modules. In this study, the performance of the backsheet under a single ultraviolet (UV) aging condition and its influence on the electrical performance of the PV module were explored so as to establish the relationship between backsheet aging and PV module performance. The results of this study show that UV irradiation is the main factor leading to the aging and cracking of backsheets. When the backsheet was exposed to a UV dose of 60 kWh/m2, the elongation at break of the backsheet was reduced by 97.04%, the tensile strength was reduced by 60.10%, the reflectivity of the backsheet was reduced by 8.36%, and the power and short-circuit current of the PV module decreased by 3.69% and 3.96%, respectively. The primary cause for the decline in PV module power was determined to be the reduction in backsheet reflectivity, which diminished the available light that could undergo re-reflection onto the solar cell, thereby resulting in a reduction of the short-circuit current. These findings provide valuable insights into the changes in the physicochemical properties of UV-aged backsheets and their power decay mechanism in PV modules. The results establish an invaluable link between the testable characteristics of backsheet aging and PV module performance.