Quantifying the impact of cell-to-cell inconsistency on electric vehicle battery degradation and utilization

Abstract

Enhancing utilization rates of battery systems in electric vehicles (EVs) substantially benefits economic efficiency and environmental sustainability. However, cell-to-cell inconsistency remains a critical barrier to fully realizing these advantages, and its system-level impact under real-world EV operation is still poorly quantified. Here we present a dataset containing 116 passenger cars and 17 buses, encompassing operational data spanning more than 3 years and up to 300,000 km per vehicle. Using practical measurements, we estimate individual cell capacity and resistance and construct a diagnostic framework of six metrics capturing variability in cell health, pack capacity retention, lifetime degradation, state-of-charge utilization, power capability and energy utilization. Our analysis reveals substantial performance degradation, including battery health reductions of 6.2% for passenger cars and 7.5% for buses, lifetime shortening by 17.7% and 22.8% and power capability decreases of 12.9% and 15.1%, respectively. Consequently, energy-resource utilization is limited to 80.7% for cars and 72.9% for buses over their operational lifespans. These findings underscore the necessity of consistency control for advancing EV battery technologies.