A Rapid Low‐Temperature Internal Heating Method for Lithium‐Ion Batteries Using Pulse Charging–Discharging Circuit

ABSTRACT Lithium‐ion batteries have high internal resistance at low temperatures, which leads to a reduction in effective capacity. Those batteries need to be preheated before use. This study introduces a method for heating batteries at low temperatures through pulse charge–discharge. The method allows for both pulse‐discharge heating and pulse charge–discharge heating. Initially, the experimental analysis is performed to assess switching frequencies, duty cycles, battery SOCs (state of charge), and pulsed charging–discharging mode on the rate of temperature increase in the battery. Subsequently, 200 tests of pulse heating cycles are carried out to examine the effects of pulse discharge heating and pulse charge–discharge heating on battery polarization and aging under various input voltages. It is found that the initial SOCs and duty cycles have a positive correlation with the rate of temperature increase, with the highest rate of temperature rise observed at a frequency of 0.1 Hz. The rate of temperature increase in the battery is largely independent of the input voltage. The findings suggest that, at the appropriate input voltage, the pulse charge–discharge heating method effectively minimizes battery aging and polarization, outperforming the heating achieved through pulse discharge alone.