Optimisation of Direct Battery Thermal Management for EVs Operating in Low-Temperature Climates

James Jeffs,Truong Quang Dinh,Widanalage Dhammika Widanage,Andrew Mcgordon,Alessandro Picarelli

doi:10.3390/en13225980

Abstract

Electric vehicles (EVs) experience a range reduction at low temperatures caused by the impact of cabin heating and a reduction in lithium ion performance. Heat pump equipped vehicles have been shown to reduce heating ventilation and air conditioning (HVAC) consumption and improve low ambient temperature range. Heating the electric battery, to improve its low temperature performance, leads to a reduction in heat availability for the cabin. In this paper, dynamic programming is used to find the optimal battery heating trajectory which can optimise the vehicle’s control for either cabin comfort or battery performance and, therefore, range. Using the strategy proposed in this research, a 6.2% increase in range compared to no battery heating and 5.5% increase in thermal comfort compared to full battery heating was achieved at an ambient temperature at −7 °C.

Highlights

One potential barrier to the mass acceptance of electric vehicles (EVs) is range anxiety, which can be exacerbated at low ambient temperatures
40% to 70% at −20 ◦ C compared to 20 ◦ C [1,2]. In addressing this issue research has been focussed on the development of heat pump technologies as a more efficient mechanism to produce cabin heat [3,4,5]
The result of this optimisation was a 6.2% increase in range compared to no battery heating and 5.5% increase in thermal comfort compared to full battery heating, at an ambient temperature of −7 ◦ C

Summary

Introduction

One potential barrier to the mass acceptance of electric vehicles (EVs) is range anxiety, which can be exacerbated at low ambient temperatures. Increased heating ventilation and air conditioning (HVAC) power consumption, coupled with reduced battery performance, leads to a range reduction of. 40% to 70% at −20 ◦ C compared to 20 ◦ C [1,2] In addressing this issue research has been focussed on the development of heat pump technologies as a more efficient mechanism to produce cabin heat [3,4,5]. Other research introduces the use of the heat pump to provide heat to the battery, thereby minimising the impact of cold temperatures [6,7,8,9]. There is a requirement to heat the battery and the cabin in such a way that the battery performance and the driving comfort, respectively, can be ensured. The objective of this research is, to develop a methodology which can actively balance the needs of these two factors according to a quantitative cost function

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Conclusion