Photovoltaic (PV) modules are subject to climate-induced degradation that can affect their efficiency, stability, and operating lifetime. Among the weather and environment related mechanisms, the degradation mechanisms of the prominent polymer encapsulant, ethylene-vinyl-acetate copolymer (EVA), and the relationships of the stability of this material to the overall reliability of Si-based PV modules were addressed. The EVA function and properties correlated to its deterioration factors as temperature, moisture, and ultraviolet radiation (UV) were discussed in this work. The main objective of this study is to review the literature on EVA encapsulation and its degradation, which promotes the loss in performance of the PV module. The deleterious effects on EVA such as photodegradation, moisture, delamination, bubble formation and potential induced degradation (PID), their relationship with the polymer structure, chemical, mechanical, optical and electrical properties are approaches carried out in this review. This paper also provides a brief review of the developing field of EVA composites technology aiming at higher performance materials.

The causes and effects of degradation of encapsulant ethylene vinyl acetate copolymer (EVA) in crystalline silicon photovoltaic modules: A review

Relation between degradation of polymeric components in crystalline silicon PV module and climatic conditions: A literature review

The degradation of photovoltaic (PV) systems is one of the key factors to address in order to reduce the cost of the electricity produced by increasing the operational lifetime of PV systems. To reduce the degradation, it is imperative to know the degradation and failure phenomena. This review article has been prepared to present an overview of the state-of-the-art knowledge on the reliability of PV modules. Whilst the most common technology today is mono- and multi-crystalline silicon, this article aims to give a generic summary which is relevant for a wider range of photovoltaic technologies including cadmium telluride, copper indium gallium selenide and emerging low-cost high-efficiency technologies. The review consists of three parts: firstly, a brief contextual summary about reliability metrics and how reliability is measured. Secondly, a summary of the main stress factors and how they influence module degradation. Finally, a detailed review of degradation and failure modes, which has been partitioned by the individual component within a PV module. This section connects the degradation phenomena and failure modes to the module component, and its effects on the PV system. Building on this knowledge, strategies to improve the operational lifetime of PV systems and thus, to reduce the electricity cost can be devised. Through extensive testing and failure analysis, researchers now have a much better overview of stressors and their impact on long term stability. • Review of reliability metrics and test methodologies for photovoltaic modules • Indicative mapping of relationships between stressors, components, failures and effects in PV modules. • Assessment on the impact of degradation and failure on LCOE and EPBT. • Review of design considerations for all components in a PV module regarding reliability. 

B. Voit

Papers

Influence of typical stabilizers on the aging behavior of EVA foils for photovoltaic applications during artificial UV-weathering