Thanks to greatly increased energy density of battery, the average driving range of electric vehicles have been advanced quite a lot. However, drastic reduction of driving range in cold ambient conditions still greatly restricts the wide application of it.
This paper presents a methodology of establishing mechanics-electricity-thermodynamics coupled full vehicle model in AMESim to investigate the energy consumption of a pure electric vehicle in cold ambient conditions. Different strategies of battery heating through Positive Temperature Coefficient (PTC) part and/or combination of Motor Waste Heat Recovery (MWHR) were also investigated to study whether there is an improvement of driving range.
Firstly, basic framework of the full vehicle model established in AMESim was introduced. Next, modeling details of individual sub-systems were illustrated respectively. Then, full vehicle energy consumption test was carried out in -7℃ ambient condition to check the simulation accuracy. Finally, a variety of battery heating strategies parameterized by heating threshold X and Coefficient of Performance (COP) were investigated to study the effects of improvement of driving range.
On the whole, simulation results of energy consumption and driving range are in good agreement with experimental data. In architecture 1, no PTC heating or only PTC heating (COP=1) was considered, the optimum X were searched out at 5℃ and 10℃, middle of a search interval of [0℃, 20℃]. The corresponding driving range is 234.528km, which is 4.7km longer than that of base scheme, namely no PTC heating. In architecture 2, which accounts for a virtual scenario of heat pump (COP=2), the optimum X was find at 25℃, near the border of specified [0℃, 30℃] search scope. The corresponding driving range is 282.541km, far longer than that of PTC heating strategy. However, as to the actual architecture that using PTC and/or MWHR, a solely utilization of MWHR was find to be the optimum, in other words, PTC heating in advance of MWHR has no benefit to the improvement of driving range.