Evaluation of Pulsed Charging Procedures and their impact on Lithium-ion Battery Lifetime for Electric Vehicle Fast Charging Applications

This paper evaluates the procedures used in pulsed fast-charging protocols to access their impact on lithium-ion (Li-ion) battery lifetime, a critical factor for electric vehicle (EV) performance and adoption. The charging methods analyzed include traditional constant-current (CC) charging, positive-pulsed current charging (PCC), negative-pulsed current charging (NPCC), and the newly proposed sinusoidal half-wave pulsed charging current (SPCC) introduced in our previous work. Inconsistent testing conditions in prior studies have led to conflicting claims about the benefits of pulsed charging for Li-ion cell lifetime. To address this, we propose a precise evaluation procedure ensuring uniformity in charge cycles and experimental conditions. The proposed method is applied to compare CC, 0.1Hz PCC, 0.1Hz NPCC, 0.1Hz SPCC, and 1kHz PCC in terms of their effects on Li-ion battery lifetime. Experimental evaluation on Nickel-Manganese-Cobalt (NMC) Li-ion cells tested for 1000 cycles revealed that pulsed methods performed similarly to the CC method when both charging rate and charging time are equalized. The results demonstrate the necessity of an evaluation procedure to accurately assess the influence of pulsed charging on battery lifespan. These findings provide guidance for drawing appropriate conclusions on the implementation of pulsed protocols for EV fast charging applications.