Optimized Adaptive Pulse Charging of Lithium-Ion Batteries Using Internal Impedance

Abstract

Minimizing the charging time of lithium-ion (Li-ion) batteries is essential for supporting the widespread adoption of electric vehicles. However, most fast-charging methods, such as the constant current-constant voltage (CC-CV) charging scheme, come at the cost of increased battery degradation. As an alternative, the pulse charging method has been shown to reduce the rate of battery degradation. In this method, the charging current includes an added ripple component that is adjusted according to battery dynamics. Battery dynamics are typically monitored by measuring battery impedance using electrochemical impedance spectroscopy (EIS); however, this approach is time-consuming and challenging to implement in most applications. Recent studies have shown that rapid battery impedance measurements using broadband methods can serve as a viable alternative to EIS. This paper introduces an adaptive pulse charging method that utilizes broadband battery impedance measurements to monitor battery dynamics in real time and control the pulse charging ripple for improved efficiency. Experimental measurements are conducted to compare the performance of the proposed charging method to the CC-CV method and conventional pulse charging methods.