Feasibility Study of Rechargeable Flexible Tandem Solar Cells for VIPV Applications Under Realistic Environments

Feasibility of direct coupling between flexible perovskite/chalcopyrite tandem solar cells and all-solid-state thin-film batteries was numerically investigated for vehicle integrated photovoltaic (VIPV) applications installed on the roof of vehicles under realistic outdoor conditions. In the case of no-load connection, the power coupling efficiency (PC_Eff) between the solar cells and the batteries showed considerably high Eff above 96% during whole daytime from spring to winter with the condition of the state of charge (SOC) less than 75%. Then, the PC_Eff gradually decreased as the SOC was approaching full charge, which was considered to be beneficial feature for preventing over charge. In the case of appropriate load connection with sufficiently charged batteries, the PC_Eff reached over 99% during whole daytime from spring to winter by the self-tuning functions of the directly integrated devices with the solar cells and the batteries. These results indicated possibility for simple and low-cost VIPV applications without any power conditioners and bypass diodes as well as extra sub-batteries.