Temperature dependency of the optical properties of photovoltaic module component layers

Abstract

Photovoltaic module performance in the field is strongly dependent on the optical properties of its component layers and the temperature dependencies of these properties. However, despite their importance, the temperature dependencies of the optical properties of many photovoltaic module components appear to have not been characterised. Hence, the assumptions regarding their optical stabilities at various temperatures have not been verified. In this study, a temperature-dependent spectrophotometry method is developed to enable this verification. The temperature dependencies of the optical properties of silicon nitride, ethylene vinyl acetate (EVA), and backsheets are characterised, and their impacts on module operations are quantified via ray-tracing simulations. It is concluded that (1) silicon nitride anti-reflection coatings are optically stable between room temperature and 85 °C, and (2) several temperature dependencies exist at different wavelengths in both EVA and backsheets, however, they do not have a significant impact on the module operation.