Technological watch

The paper presents a solution for repair and preventive maintenance of PV modules with backsheets that degrade in the field, using a flowable silicone sealant. It is shown that the material fills the cracks and restores electrical insulation. Suggestions for optimal implementation are given.Photovoltaic (PV) modules with a degrading backsheet pose a challenge for solar park operators and other players in the PV value chain. Some types of backsheets are known to develop cracks because of an aging?induced change in the mechanical characteristics of the material during operation in the field, which result in a loss of insulation resistance. In this work, we present a solution for repair and preventive maintenance based on a single component flowable silicone sealant. The method fills the cracks present in the backsheet with an insulating material, restoring insulation resistance, and provides a protective layer to avoid subsequent degradation. The solution was successfully implemented on the back of PV modules with co?extruded polyamide backsheet (‘AAA’), which showed deep cracks following degradation 5–7?years of operation in a solar park. The repaired modules had a restored insulation resistance of several hundred M? as observed with wet leakage testing and maintained a high resistance after accelerating aging. This repair technology can be done in the field and is an alternative solution to module replacement.