Hierarchical layout optimisation of distributed charging infrastructures on expressways

Range anxiety has become an obstacle to intercity travel by electric vehicle (EV), which has restricted the promotion of EVs. Balancing the supply of charging infrastructures (CIs) on expressways with intercity travel demand should therefore be paid more attention. In this context, a method for estimating charging demand is proposed at the road scale to analyse the disparities between supply and demand (DSD) of CIs. Based on the charging supply at service areas, the method was applied to future scenarios with varying EV penetration rates. Then, a construction plan and a hierarchical optimised model for distributed CIs on expressways were developed in order to meet the DSD. Finally, planning for expressway CIs in the Beijing–Tianjin–Hebei urban agglomeration was considered. The results showed that only 30–40% of the peak charging demand can be met solely on service areas. The DSD spreads from the urban centre to the periphery as the EV penetration rate gradually increases. Through optimisation of the hierarchical distribution of CIs, the construction of CIs should be at intervals greater than 10 km. The results of this study provide theoretical support for the planning and construction of CIs on expressways, which will help promote the development of EVs and expressway electrification.