Durable polyolefin encapsulants in aged photovoltaic modules

Abstract

We investigated the long-term durability of thermoplastic polyolefin (TPO) encapsulants in crystalline-silicon (c-Si) photovoltaic (PV) modules that were exposed for up to approximately 10 years or damp-heat (DH)-exposed at 85 °C and 85% relative humidity (RH). No significant degradation was observed in c-Si PV module based on the TPO encapsulant after a long-term DH test at 85 °C/85% RH for 8000 h. The Fourier transform-infrared absorption spectrum indicated that oxidative degradation of the TPO encapsulant in the module occurred on the glass side after the DH test, whereas the oxidative products of the TPO encapsulant did not decrease the PV performance of the module. No significant oxidative degradation of the TPO encapsulant in the module was observed after approximately 9 years of outdoor exposure by Raman spectroscopic measurements. Our results indicate that TPO is a promising alternative encapsulation material for enhancing the long-term durability of c-Si PV modules furthermore.