Modelling aluminium energy storage systems comprising ionic liquid and aqueous electrolyte cells: Case studies in high-performance electric vehicles

This paper models hybrid energy storage systems (HESSs) composed of ionic liquid Al-ion batteries (ILAIBs) and aqueous Al-ion batteries (AAIBs) for electric vehicle (EV) propulsion. Al-ion batteries are being developed as alternatives to existing battery technologies as Al is an abundant, non-toxic material. Al-ion batteries can be tailored for high power density or high energy density and as such are suitable for HESSs for EVs. In this paper, Al-based chemistries are substituted for one or both of the Li-ion battery (LIB) and supercapacitor (SC) components of the benchmark LIB-SC HESS, and thus the ILAIB-SC, LIB-AAIB, and ILAIB-AAIB HESSs are proposed and modelled with a high-performance EV. The performance of each HESS is compared with that of the conventional LIB-SC HESS, in terms of mass, volume, initial costs, and vehicle lifetime costs. Results show that using the ILAIB as the main energy storage in the HESS can reduce vehicle lifetime costs by 16% as compared with the LIB-based HESSs, but the volume of ILAIB-based HESSs is ten times that of LIB-based HESS. Using the AAIB as the second energy storage can reduce vehicle lifetime costs by 2% but also benefit from 2% less mass and 1% less volume as compared with the SC-based HESSs. Considering both financial costs and feasibility of deployment, the LIB-AAIB HESS is the most viable hybrid combination for high-performance EV propulsion at the present stage.