Experimental study on pulse self–heating of lithium–ion battery at low temperature

Battery warming at low temperature is a critical issue affecting battery thermal management. In this study, the pulse self–heating strategy is proposed to enable quick and safe warming of lithium–ion battery at low temperature. The battery is heated up using pulse self–discharge. This strategy can heat up 18,650 commercial battery with a control circuit and alleviate the battery degradation during heating. Compared with continuous direct current self–heating, the battery can be heated up from −10 °C to 10 °C by pulse heating within 175 s while the direct current heating consumes 280 s with approximating polarization voltage. The effects of ambient temperature, switching interval, and initial state–of–charge on heating performance are further investigated. Heating duration is found to be insensitive to the switching interval in the studied range. Conversely, battery internal resistance and off–period voltage at different ambient temperatures and initial state–of–charges are found to be the predominant factors that influence heating duration. Heating duration in the range of 150–180 s is achieved at ambient temperature ranging from −10 °C to 0 °C. In real applications, pulse heating is recommended to be performed at higher initial state–of–charge (>0.8), at which heating duration is within 200 s.