Modeling spare capacity reuse in EV charging stations based on the Li-ion battery profile

Lithium-ion batteries, widely used in electric vehicles (EVs), have a specific charging profile where the power consumed varies over time and defines the amount of power the charging station needs to deliver. Achieving a proper tradeoff between charging levels, number of vehicles, and electric capacity of the plant is challenging. In order to give a solid basis for the deployment of efficient charging systems, we propose a bi-dimensional Markov chain model that considers the practical characteristics of Li-ion charging profiles. To this end, we build two scenarios that differ in their capacity to handle idle slots. We show through extensive numerical analysis that the use of spare sockets in different sizes of charging stations contributes to better energy utilization. Moreover, we apply the proposed model to the case of the city of Rio de Janeiro and show that, in a foreseeable future, if all ICE (Internal Combustion Engine) vehicles were replaced by EVs, the adoption of charging station with spare sockets will produce significantly better results in terms of availability of the station, number of admitted vehicles, and energy utilization.