The Influence of the EVA Film Aging on the Degradation Behavior of PV Modules Under High Voltage Bias in Wet Conditions Followed by Electroluminescence

Abstract

The quality of the materials used in the PV module assembly is very important. Since photovoltaic modules are normally connected in series some of them are exposed to a high system voltage between the cells and the grounded frame. To investigate the influence of the EVA film quality on the stressed photovoltaic module degradation we in-house developed mini modules with p-type monocrystalline silicon solar cells. The modules were assembled with EVA films of equivalent qualities but different ages and exposed to an accelerated test (RH = 85%, T = 60 °C). While modules with a "fresh" EVA film exhibit almost no degradation, the modules with the "aged" EVA film degrade very rapidly and severely. Their degradation rate was around 0.2 %/day during the 2000 hours of damp heat test. The strong silver line corrosion is due to the peroxide leftovers in the "aged" EVA films.

Mathematical model to estimate the maximum power output of a total cross tied connected PV array during partial shading condition

“…The properties of the PV module encapsulant such as water vapour transmittance rate, volume resistivity or polarity strongly affect the potential-induced degradation [28] of PV module. Hence, the performance of a PV module also degrades along with the age.…”