Field Study of Backsheet Repair with Flowable Silicone Sealant

We investigate the repair of backsheets by silicone coating on PV modules that had been degraded during years of operation in a solar park, and study the feasibility of spray repairing modules without dismounting. We discuss two field trials. In the first one, 51 modules were repaired by spreading a flowable silicone sealant using a squeegee and left to operate further in the field for 1.5 years. We find that the effectiveness of the repair in fixing the low Riso caused by cracks is maintained after further field aging. In the second study, spraying of the silicone coating in the field was studied. It was found to be a feasible option on a large scale without dismounting PV modules. By utilizing a two-worker maintenance crew, the cost relating to the spray application is estimated to be around $11 per module, contributing to making backsheet repair cost effective solution to full replacement of modules.