Detection of acetic acid produced in photovoltaic modules based on tin film corrosion during damp heat test

A novel, nondestructive low-cost detection method for acetic acid distribution in a photovoltaic (PV) module during the damp heat (DH) test based on reflectance changes of tin film sensors is proposed and demonstrated. The sensor consists of a tin film evaporated on a glass substrate. Nineteen sensors and one gold film are laminated in the PV module, and the DH test was performed at 85 °C and 85% relative humidity for 7203 h. The time range of measurement can be controlled between 2000 to 6000 h by adjusting the tin film initial thickness from 70 to 160 nm.