Rapid restoration of electric vehicle battery performance while driving at cold temperatures

Abstract

Electric vehicles (EVs) driven in cold weather experience two major drawbacks of Li-ion batteries: drastic power loss (up to 10-fold at −30 °C) and restriction of regenerative braking at temperatures below 5–10 °C. Both factors greatly reduce cruise range, exacerbating drivers' range anxiety in winter. While preheating the battery before driving is a practice widely adopted to maintain battery power and EV drivability, it is time-consuming (on the order of 40 min) and prohibits instantaneous mobility. Here we reveal a control strategy that can rapidly restore EV battery power and permit full regeneration while driving at temperatures as low as −40 °C. The strategy involves heating the battery internally during regenerative braking and rest periods of driving. We show that this technique fully restores room-temperature battery power and regeneration in 13, 33, 46, 56 and 112 s into uninterrupted driving in 0, −10, −20, −30 and −40 °C environments, respectively. Correspondingly, the strategy significantly increases cruise range of a vehicle operated at cold temperatures, e.g. 49% at −40 °C in simulated US06 driving cycle tests. The present work suggests that smart batteries with embedded sensing/actuation can leapfrog in performance.