Battery-Electric Powertrain Design Analysis for an Efficient Passenger Vehicle

In this paper, different battery-electric powertrain designs have been investigated for a passenger hatchback vehicle. Specifically, the energetic effect of technological and topological choices in the powertrain design is analyzed. Thereto, a feasible set of battery-electric powertrain configurations, varying in topology, machine technology, and transmission architecture is considered. For each configuration, the electric machine size(s), gear ratio value(s), and controls are jointly optimized in an integrated (bi-level) fashion using the particle swarm optimization (PSO) algorithm. The results showcase that the combined component and topological choices can lead to a maximum reduction of 17.61% in the vehicle's energy consumption and can significantly influence the total electric machine sizing in the powertrain. Furthermore, it has been shown that the energy consumption of the vehicle is lowered by: (i) using two axles (AWD) instead of one axle (RWD) to drive the vehicle (−12.0%); (ii) choosing a distributed drive system, over a central drive system (−6.6%); followed by (iii) using permanent-magnet-synchronous type machine(s) instead of asynchronous induction machines (−3.0%); and, (iv) using multiple electric machines in single-axled topologies (−0.80%). The smallest energetic impact was observed for (v) using two-speed instead of single-speed gear box(es) (−0.38%); however, it resulted in the largest reduction in the (total) electric machine size(s) (−10.3%).