Detection of snail tracks on photovoltaic modules using a combination of Raman and fluorescence spectroscopy

Snail tracks are discolorations of the silver fingers on solar cells. We present a measurement system that can detect snail tracks. Their origin is unknown, but they are thought to be linked to micro cracks in the solar cell. Regions with micro cracks on a photovoltaic module were identified using electroluminescence measurements. Based on the electroluminescence data the faulty regions were mapped with a system that uses a combination of Raman and fluorescence spectroscopy. Our results show that our measurement system is a powerful tool for detecting snail tracks.