Development of an ion-barrier film on solar panel glass

Potential Induced Degradation (PID) is becoming a greater risk for contemporary modules due to higher voltage connections as well as the availability of ungrounded PV systems using transformer-less or bi-polar inverter technology, both of which create a higher operating voltage between the PV module and frame. This higher voltage is theorized to induce ions to migrate through the PV module´s glass to the cell´s surface and thereby increase the leakage current. In this work we demonstrate the reduction and possible prevention of PID by employing functionalized films on the inner and outer surfaces of the PV module front glass. These films have the potential to retard the mobility of both water and charge carriers into and out of the glass. We investigate how variations in the thickness and surface energy of the films affect PID and we investigate how typical anti-reflective coatings in use today on the outer surface of PV module glass affect PID when compared to no coating and to high durability hydrophobic coatings. Low-cost optically optimized glass coatings are an attractive and promising solution for producing PID-resistant PV modules that are independent of the cell technology.