Error analysis of aged modules with cracked polyamide backsheets

Within the last years, an increased occurrence of backsheet cracking, especially of Polyamide-based backsheets, was observed in PV installations and reported in literature. Thus, a detailed failure analysis on cracked polymeric backsheets was performed in order to identify the drivers leading to the unexpected behaviour of the Polyamide multilayer composites. Using a unique combination of analytical tools allowed for deducing a spatially resolved representation of material degradation effects within a PV module for the first time. The correlation of local material degradation effects with the influence zones of external and internal stresses enables the derivation of the main factors for the formation of different types of cracks in Polyamide backsheets. [Display omitted] •Detailed failure analysis on cracked Polyamide (PA)-backsheets: microcracks, longitudinal cracks and squared cracks.•Main drivers: negative, anisotropic thermal expansion of the coextruded PA-backsheet and the physical aging of PA12.•Answer, why these failures could not been predicted by the standard material and module type approving test procedures.