Abstract
A significant disadvantage of battery electric vehicles compared to vehicles with internal combustion engines is their sharply decreased driving range at low temperatures. Two factors are primarily responsible for this decreased range. On the one hand, the energy demand of cabin heating needs to be supplied by the vehicle’s battery since less waste heat is available from the powertrain, which could be used to cover heating demands. On the other hand, a limited capability to recuperate at low temperatures serves to protect the battery from accelerated aging, which ultimately leads to less energy regeneration. This paper analyzes the impact of both factors separately on a battery electric vehicle’s driving range. Additionally, this paper provides technical requirements for the implementation of an electrothermal recuperation system. Such a system has the potential to reduce the impact of both abovementioned factors on driving range by enabling the direct usage of regeneratable energy for heating when battery charging is limited under cold conditions. The presented analysis is based on BMW i3 and Tesla Model 3 datasets, which combined cover more than 125 trips in and around Munich at different ambient conditions. The results show that the range can decrease by up to 31.9% due to heating and by up to 21.7% due to limited recuperation, which gives a combined maximum range decrease of approximately 50% under cold conditions. Additionally, it was found that a heater with a short reaction time in the lower millisecond range and a power capability of 20 kW would be sufficient for an electrothermal recuperation system to enable the utilization of unused regenerative braking potentials directly for heating.
Highlights
The mitigation of climate change is one of society’s greatest challenges in the 21st century [1]
It should be noted that such a heater needs to be controlled directly via CAN bus and not, as is usually the case, via CAN and LIN bus. Such a system was investigated by Steinsträter et al [28] and they could show that a battery electric vehicles (BEVs) can achieve a range increase of 8% at −10 ◦C compared to a BEV that is not able to use regenerative braking potentials directly for heating (ETR) under the same conditions
One of the greatest barriers for customers today to purchase battery electric vehicles is their limited driving range compared to the range of combustion engine vehicles
Summary
The mitigation of climate change is one of society’s greatest challenges in the 21st century [1]. To reduce the impact of limited recuperation and an increased heating energy demand at low temperatures on a BEV’s range, Lieb et al [30] and Steinstraeter et al [28] investigated the utilization of unused regenerative braking power for cabin heating by bypassing the battery with a heater that is fed directly with recuperation power from the electric machine(s). The strategy includes a thermal battery and cabin preconditioning, as well as the utilization of electric machine waste heat to minimize the energy that needs to be supplied by the battery for heating during a trip They demonstrated that at an ambient temperature of −18 ◦C and an energy consumption reduction of more than 5% is achievable with the system for the New European Driving Cycle (NEDC)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
