Experimental study on electrochemical, starting-up, and energy-saving properties of a hybrid supercapacitor as automotive starter power under low-temperature conditions

Hybrid supercapacitors (HSCs) are considered a potential energy storage device due to their unique advantages. In this study, the electrochemical-heat generation behaviors of HSCs were analyzed through experimental tests. Then, the electrochemical characteristics, start-up performance, and fuel consumption of 12 V/70 Ah HSCs, a lead-acid battery, and an LiFePO4 battery were compared to further evaluate the law and mechanism of the low-temperature condition, leading to the aforementioned performance attenuation. After 100 continuous charge/discharge cycles, the capacity retention rate of the HSCs was 2.53 % higher than that of the lithium cell, and the Coulombic efficiency of the lithium cell was 0.56 % higher than that of the HSCs. Additionally, when the temperature dropped from 0 °C to −20 °C, the overall fuel consumption of the HSC energy storage power increased by 0.11 mL. When the temperature decreased from −15 °C to −20 °C, the discharging capacity of the HSC energy storage power decreased slightly by 2.5 Ah and the charging time increased by 0.36 h. Overall, the HSC energy storage power exhibited optimal low-temperature start-up performance, fuel-saving effect, and lower capacity attenuation. Relevant research is expected to provide experimental data and theoretical support for the industrialization of HSCs.