Degradation of Monofacial Double Glass and Glass Backsheet Photovoltaic Modules with Multiple Packaging Combinations

The long-term reliability of photovoltaic (PV) modules is essential to decrease the levelized cost of electricity and is dependent on module packaging choices. In this paper, we study the degradation of double glass (DG) and glass-backsheet (GB) PV modules with ethylene-vinyl acetate (EVA) and polyolefin elastomer (POE) encapsulants using multicrystalline PERC cells under accelerated exposures including modified damp heat (mDH) and mDH with full-spectrum light (FSL). The results showed that the modules with opaque rear encapsulant have greater power loss on average than those with UV-cutoff rear encapsulant for each module type. The dominant degradation mechanism was series resistance (Rs) increase indicating interconnect corrosion for most module types. In addition to the increased Rs, GB modules with UV-cutoff rear encapsulant experienced power loss by transmission loss, and the POE_GB type under mDH+FSL also had more cell shunting. For modules with opaque rear encapsulant, the POE_DG type under mDH+FSL had power loss dominated by transmission loss.