In this study, we fabricated a parallelly connected Li-ion batteryercapacitor hybrid cell to combine the advantageous characteristics of Li-ion battery and supercapacitor, high energy density and high power density, respectively, and investigated its discharging characteristics over a wide temperature range from -40 to $25^{circ}C$<. At the initial state of discharging of the hybrid cell, the power was mostly provided by the supercapacitor and then the portion of the Li-ion battery was gradually increased. By installing a switching system into the hybrid cell, which controls the discharging sequence of Li-ion battery and supercapacitor, the maximum power was improved by 40% compared with non switching system. In addition at low temperatures, the power and discharging time of the hybrid cell were significantly enhanced compared to a battery-alone system. The hybrid cell is expected to be applied in electric vehicles and small domestic appliances that require high power at initial discharging state.
