Battery cell balance of electric vehicles under fast-DC charging

Electric vehicle (EV) range, recharge opportunities and time to recharge are major barriers to mainstream acceptance. Fast-DC charging has the potential to overcome these barriers. This research investigates the impact of fast-DC charging on battery cell balance, charge capacity and range for an EV travelling long distances on an 'electric-highway'. Two commercially available EVs were exposed to a series of discharge and fast-DC charge cycles to measure cell balance and charge capacity. The vehicles' battery management systems (BMS) were capable of successfully balancing individual cells and hence maintaining the batteries' charge capacity. Although fast-DC charge levels and discharge safety margins significantly reduced the vehicles' charge capacity and range as stated by the manufacturer, these values remained stable for the test period. In regards to cell balance and charge capacity, our research suggests that fast-DC charging technology is a feasible option for EVs to travel large distances in a day.