Study of high-performance film heater based on nanocarbon available at a low voltage

Abstract

Li batteries used in electric vehicles have a high discharge voltage and an excellent energy density. However, in a low-temperature environment, their output sharply decreases, which decreases the total cruising distance of the vehicle. We developed a film-type battery heater to enhance the performance of Li batteries in a cold state. This battery heater can increase the temperature of a Li-ion battery soaked in a cold state from −20°C to 0°C within several minutes. To test the performance of the battery heater developed at KETI, various stacking structures (Al/battery heater/Al) depending on the thickness of Al plate were prepared, which were stored at −20/6C for one day. When a DC voltage of 4 V was applied to the battery heater, the surface temperature of the Al plate increased dramatically to above 0°C within several minutes. As the thickness of the Al plate decreases, the heating-up rate becomes faster. The film provided almost stable heating behavior without degrading performance, even with the increasing number of on/off cycles.