sharedCharging: Data-Driven Shared Charging for Large-Scale Heterogeneous Electric Vehicle Fleets

Our society is witnessing a rapid vehicle electrification process. Even though being environmental-friendly, electric vehicles have not reached their full potentials due to prolonged charging time. Moreover, unbalanced spatiotemporal charging demand/supply along with the uneven number of charging stations between heterogeneous fleets make electric vehicle management more challenging, e.g., surplus charging stations across a city for electric buses but limited charging stations in some regions for electric taxis, which severely limit the charging performance of the whole electric vehicle network in a city. In this paper, we first analyze a large-scale real-world dataset from two heterogeneous electric vehicle fleets in the Chinese city Shenzhen. We investigate their mobility and charging patterns and then verify the practicability and necessity of shared charging. Based on the insights we found, we design a generic real-time shared charging scheduling system called sharedCharging to improve overall charging efficiency for heterogeneous electric vehicle fleets. Our sharedCharging also considers sophisticated real-world constraints, e.g., station spaces, availability of charging points, real-time timetable guarantee, etc. More importantly, we take the electric bus and electric taxi fleets as a concrete example of heterogeneous electric vehicle fleets given their different operating patterns. We implement and evaluate sharedCharging with streaming data from over 13,000 electric taxis and 16,000 electric buses, coupled with the charging station data in the Chinese city Shenzhen, which is the largest public electric vehicle network in the world. The evaluation results demonstrate that the proposed sharedCharging reduces the waiting time by 63.5% and reduces the total charging time by 15% on average for e-taxis.

我们的社会正见证着车辆快速电动化的进程。尽管电动汽车环保，但由于充电时间过长，其潜力尚未完全发挥。此外，时空充电供需不平衡以及不同类型车队之间充电站数量不均，使得电动汽车管理更具挑战性，例如，城市中电动公交车的充电站过剩，但某些地区电动出租车的充电站却有限，这严重限制了城市中整个电动汽车网络的充电性能。在本文中，我们首先分析了来自中国深圳两个不同类型电动汽车车队的大规模真实数据集。我们研究了它们的出行和充电模式，然后验证了共享充电的实用性和必要性。基于我们的发现，我们设计了一个通用的实时共享充电调度系统，名为sharedCharging，以提高不同类型电动汽车车队的整体充电效率。我们的sharedCharging还考虑了复杂的现实约束条件，例如站点空间、充电点的可用性、实时时间表保障等。更重要的是，鉴于电动公交车和电动出租车车队不同的运营模式，我们将它们作为不同类型电动汽车车队的具体示例。我们利用来自13000多辆电动出租车和16000多辆电动公交车的流数据以及中国深圳的充电站数据（深圳拥有世界上最大的公共电动汽车网络）来实施和评估sharedCharging。评估结果表明，所提出的sharedCharging系统使电动出租车的平均等待时间减少了63.5%，总充电时间减少了15%。