Mechanical behavior and lamination issues of solar modules containing elastomeric and amorphous encapsulates

Solar cells mostly are embedded into a soft polymer matrix using vacuum lamination process. Since the early 80´s Ethylenevinylacetate (EVA) is widely used for this purpose. The material is of thermoplastic nature, but cross links covalentely under high temperatures to a non-melt able elastomer. In this work, a method for mathematically describing isothermal cross linking reaction of a commercially available EVA fast cure is presented using Arrhenius relation. Dynamicmechanical analysis (DMA) was carried out using a rotational rheometer at different temperatures. Considering the demand on shorter processing times, neat thermoplastic and reversible melt able polymers come more and more into focus. For a Polyvinlybutyral (PVB) and a Thermoplastic Silicon Elastomer (TPSE) processing and mechanical have been determined using DMA under constant temperature sweep. Results show that PVB has lowest, TPSE highest transition temperatures from solid-like to liquid-like behavior. On the basis of these results, laminated glass beams have been manufactured using vacuum lamination process. Resulting laminates have been tested at room temperature for their elastic behavior under 3- point bending mode and their creep behavior when holding a constant load. Elastic behavior was found to be strongly depended on polymer interlayer thickness and materials used. Creep was observed to be strongest for PVB.