Methodology for local ageing and damage development characterization of solar glass/encapsulant interfaces under superimposed fatigue stresses and environmental influences

In this paper, a novel fracture mechanics test-setup was developed, implemented and applied for assessment of the fatigue delamination behavior glass/encapsulant laminates under superimposed mechanical stresses environmental influences. Double cantilever beam (DCB) specimens with glass substrates were prepared using ethylene vinyl-acetate copolymer (EVA) or polyolefin elastomer (POE) encapsulants. Displacement-controlled tests conducted at 80 °C dry (5% rh) humid (80% conditions. The damage zone ahead crack tip monitored topside mounted camera system. A superior resistance POE based double ascertained. Under less service-relevant, hot-dry conditions, exhibited mm-sized process tip, in which void nucleation fibril formation took place. While laminate failed also cohesive manner within encapsulant 80% rh (i.e., hot-humid), propagating glass/EVA close to interface brittle manner. Local ageing mechanisms confirmed fractured EVA by XPS. superposition thermal along humidity resulted sodium ion migration presumably promoting deacetylation EVA. Interestingly, analyzed degradation products good agreement data obtained damp heat aged glass/foil PV modules characterized subsequently monotonic testing. main advantage methodology is high acceleration factor (50 100x faster) compared conventional testing modules.