Research on the flexible photovoltaic cell in different bending forms

Flexible photovoltaic cells maintain high photoelectric conversion efficiency whose superior flexibility indicates the huge potential to integrate with complex surfaces, such as curved building exterior envelopes, portable smart devices, nonplanar vehicle skins, etc. Different from the planar-type PV, the varied application scenarios and complicated system design lead to the non-uniform solar irradiance distributed among the flexible solar cell’s total irradiance receiving region, which requires refined model establishment to describe and analyse the cell’s photoelectric performance. In this paper, the utilization of flexible solar cells was reviewed. Then experimental study was conducted in a laboratory environment to research on the photoelectric performance by flexible CIGS cells under specific working conditions (bending the solar cell into different arc-shaped forms assisted by the 3-D printing bases). Simulation workflow for the photoelectric theoretical model of the flexible solar cell under non-uniform illumination distribution caused by different bending forms is proposed and verified using the experimental results. The combined optical-electrical model is based on the single-diode model of the solar cell and the current continuity equation. Finite element method is applied to investigate the emitter and the finger regions’ voltage and current density respectively. Simplified method to predict the bended PV cell’s photoelectric power is proposed and the calculation deviation with the two-dimensional mathematical model is compared. The electrical power output by the flexible cells in different bending forms (cylindrical, semi-elliptic, parabolic) is investigated simulatively to provide guidance for designing curved surfaces.