Contact-free Determination of Ethylene Vinyl Acetate Crosslinking in PV Modules with Fluorescence Emission

The degree of crosslinking of ethylene vinyl acetate (EVA) is a decisive factor for the photovoltaic (PV) modules reliability. Numerous chemical or physical methods may be applied to determine the extent of crosslinking reaction in the EVA material. The usual and most accurate ones are destructive as they require a sample of material from the module. In this work we present a contactless and non-destructive method for monitoring the crosslinking process of EVA based on fluorescence spectroscopy. We show the correlation of fluorescence emission intensity of EVA when submitted to UV light with its curing grade determined by a rheological method. This approach is of interest for in-line monitoring of the crosslinking during the lamination step and for quality control after production.