Efficient Area Matched Converter Aided Solar Charging of Lithium Ion Batteries Using High Voltage Perovskite Solar Cells

Abstract

Efficient solar charging of a battery has been demonstrated in the past by sizing batteries many times that of a solar cell to reduce the effective current density experienced by the battery. Although efficient, such a strategy of coupling a battery up to 10 times larger with a solar cell will make solar-battery integration more challenging and limit the size, and thus maximum power output, of an integrated device. Area matched LFP-LTO (lithium iron phosphate, lithium titanate) battery solar charging using high voltage lead halide perovskite solar cells with a boost converter gave a maximum overall efficiency of 9.9% and a high 14.9% solar to battery charging efficiency. Two differently sized systems were compared using the same converter, and an exergy analysis was performed, showing limitations of converter usage in solar-powered internet of things (IoT) devices and size dependent battery losses.