Optimal Sizing and Analysis of Hybrid Battery Packs for Electric Racing Cars

The electrification trend is spreading not only in the field of traditional vehicles but also in the racing one, with challenging power and range demands. As an example, the next generation of Formula E will increase power up to 600 kW, almost triplicating the actual standards. In this article, we investigate the potential benefits of hybrid battery packs (H-BPs) in a racing scenario. H-BPs combine different cell technologies aiming at exploiting their respective high-power and high-energy densities. To this purpose, we formulate a codesign optimization problem that finds the optimal H-BP configuration to minimize the race time, on a given circuit. As a case study, the next generation of Formula E on the 2021 Rome Formula E ePrix is considered. Results show a significant gain in terms of race time, compared to a single-cell chemistry battery pack. Moreover, the analysis points out interesting results on the optimal power split strategy and the role of mechanical brakes.