Field Performance and Thermal-Electrical Mismatch Mechanism of Curved CIGS BIPV Modules: An Outdoor Experimental Study

Flexible photovoltaic modules offer an innovative approach for Building Integrated Photovoltaics (BIPV) on non-planar envelopes. However, the dynamic outdoor environment aggravates the photoelectric mismatch mechanism caused by complex curved geometries. This study experimentally investigates the outdoor experimental investigation into the dynamic electrical and thermal performance of large-scale curved CIGS modules equipped with bypass diodes. Six representative configurations—flat, length-convex(lgvx), length-concave(lgcv), width-convex(wdvx), width-concave(wdcv), and wavy—were continuously monitored under real weather conditions in Hefei, China. The results indicate that while flat modules maintain the highest daily energy yield (453.32 Wh) , the wdvx in longitudinal direction exhibits exceptional adaptability, achieving an average Performance Ratio (PR) of 91.46% and outperforming the flat type during low solar altitude periods in the day. Infrared thermal imaging reveals significant temperature gradients driven by the mismatch effect, with the lgcv module reaching a peak temperature of 65.88°C. Furthermore, the I-V characteristic curves demonstrate that non-uniform self-shading triggers bypass diode activation, resulting in severe step-like current drops and multiple power peaks in concave and wavy shapes. These findings offer crucial practical guidelines for optimizing cell layout and thermal management in curved BIPV envelops.