In this work, a novel acausal and reconfigurable battery pack model is presented. The model structure adopted for the battery cell is based on an equivalent circuit representation. The circuit elements are modified to take account of both hysteresis and diffusion limitation. The latter is known to be a nonlinear function of large operating currents or long operating times. It is shown that the integration of a current dependent time constant within the cell model better emulates the solid diffusional dynamics of lithium intercalation into the active material under large electrical loads. The advantages of an acausal modeling approach, when scaling-up individual cell models into a complete battery system are also presented. Particular consideration is given to emulating the impact of cell to cell variations on pack performance. Using statistical analysis of battery tests, cell model parameter variations are characterized and quantified. The cell and scaled-up pack model are parameterized for a number of commercially available cell formats, energy capacities and chemistries. The new models are validated using transient, real-world, electrical data measured from an electric vehicle (EV) operating within an urban environment.

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.

Previous research has focused on the use of heat pumps in electric vehicles, with the focus on recuperating heat from, normally, ambient and one thermal source on the vehicle. Here 5 potential thermal sources on a vehicle have been identified and thorough testing on the benefit of each source has been performed. The results presented suggest the motor, a thermal storage device, and cabin exhaust extraction should be used >80% of the time according to the scenarios tested, while battery heating and transmission heat extraction should be used subject to conditions on the ambient temperature and drive cycle.

Here is information on how to publish, spread your research, and search for your publications. Most of LiU's research publications are directly imported into DiVA from the Web of Science. Before registering a publication, always check if the publication is already in DiVA!

Here is information on how to publish, spread your research, and search for your publications. Most of LiU's research publications are directly imported into DiVA from the Web of Science. Before registering a publication, always check if the publication is already in DiVA!