Delamination of c-Si Module Encapsulation: Insight into Causes and Long-Term Effects

The encapsulation of photovoltaic (PV) modules insulates solar cells and internal electrical components, and protects them from environmental stresses. Encapsulant delamination is a common mode of failure, and can appear immediately after manufacturing (quality issues) or it can occur over time (degradation). In both cases, the long-term impact of delamination on module performance is poorly quantified. In this work the causes and effects of delamination were examined in greater detail. Inhomogeneities during lamination (e.g. temperature, uncured material composition) form areas with different properties which are expected to be more susceptible to delamination over time. To assess the long-term effect of delamination on performance, single cell c-Si modules with an ethylene-vinyl acetate (EVA) encapsulant and poor lamination quality or selective delamination were manufactured and subjected to a series of accelerated weathering tests (damp heat (DH), thermal cycling (TC), ultraviolet (UV) light). The extent of delamination increased over time, and lead to a higher rate of performance-loss compared to reference modules, for example, more than double in the case of damp heat exposure.