Study on the Effect of Different AC Excitations on the Internal Heating for Low-Temperature Batteries

In cold climates, lithium-ion batteries have deteriorated charge-discharge performance so that the driving range of electric vehicles (EVs) will drop substantially. Thus, low-temperature lithium-ion batteries must be preheated to enhance the life cycle and available capacity. Abundant internal AC heating methods have proposed to attain a high heating speed. However, the effect of different AC excitations, including the current waveforms and RMS values on the internal AC heating has not been studied. Therefore, in this paper, heating experiments are conducted to explore the different AC waveforms and RMS of AC excitation for the lithium-ion battery heating at low temperatures. Experimental results indicate that the square wave can achieve fast heating speed. Moreover, this excitation can heat the battery from -20°C to 5°C within 130s.