Discoloration of PV encapsulants

Discoloration of EVA encapsulants with accompanying module power loss was observed in the 1990s. Detailed analyses of the failure modes and recommendations on minimizing the effects have been published. Recent studies, however, indicate that the discoloration has not been eliminated in fielded photovoltaic (PV) modules and is still a major contributor to power degradation in crystalline silicon PV modules. Recent changes in the PV industry and its supply chain make it likely that this phenomenon could be a more significant problem (with significant relearning) in the future. This paper will review the past work on EVA discoloration, present and explain the new results on long-term degradation, and make recommendations on how to limit encapsulation discoloration going forward.