Optimizing electric carsharing system operations and battery management

Abstract

Shared electric vehicles (SEVs) have emerged as a promising solution for promoting sustainable urban mobility. However, ensuring the efficient operation and effective battery management of SEV systems remains a complex challenge. To address this issue, this paper introduces an integrated optimization framework for SEV systems that jointly considers Vehicle-to-Grid (V2G), Battery-to-Grid (B2G), plug-in charging, and battery swapping. The proposed approach is built on a space-time-energy network model that simultaneously optimizes battery charging and discharging scheduling together with SEV operations, such as relocations and battery swapping. The objective is to maximize profit while addressing operational constraints and the complexities of energy management within SEV systems. Given the substantial complexity of large-problem scales, the paper introduces a column generation-based heuristic algorithm. Additionally, a rolling horizon approach is employed to enable real-time decision-making under dynamic operational conditions. Extensive experiments are conducted to evaluate the effects of key parameters, such as the rolling horizon settings, charging rates, fleet sizes, and the number of stocked batteries. The effectiveness of various energy management strategies is also assessed, ranging from plug-in charging alone to its combinations with battery swapping, V2G, and B2G. Numerical results show that under low carsharing rental demand scenarios, plug-in charging alone is a cost-effective option. Moreover, battery swapping is found to be particularly effective as an auxiliary recharging method when the SEV fleet is limited, charging rates are low, or carsharing demand is high. Overall, this study provides theoretical foundations for the integration of vehicle operations and energy management in shared electric mobility systems.