The effect of moisture on the degradation mechanism of multi-crystalline silicon photovoltaic module

摘要

Moisture can diffuse into a photovoltaic (PV) module through its breathable back-sheet and its ethylene vinyl acetate (EVA) sheet. Therefore moisture-induced degradation mechanism is investigated with multi-crystalline (m-Si) silicon PV module. Three types of accelerated tests (ATs) were conducted to evaluate the effect of temperature and humidity on the degradation of m-Si PV module. The thermal activation energy for degradation, 0.492 eV, was calculated. Electroluminescence image shows that moisture has an effect on the module degradation. Electrical measurements, Dark Ⅳ and Suns V_(oc) indicate that series resistance (R_s) contributes to drop in power output. The results of SEM&EDX and Auger Electron Spec-troscopy (AES) reveal that corrosion occurred at the region of solder joint and also show that the oxide concentration on the metal electrode increased after the AT.