ADMM-Based Balanced Charging Strategy for Electric Vehicles

The electric vehicle (EV) market is expanding rapidly, and using renewable energy to power EVs not only enhances environmental sustainability but also significantly reduces greenhouse gas emissions. As a result, more service providers are introducing EV fleets to promote sustainable development. However, EVs require specialized charging infrastructure, which presents technical and economic challenges. Therefore, developing smart charging strategies to optimize the EV fleet charging process is crucial. This paper proposes a convex optimization model aimed at minimizing energy costs and battery degradation costs to reduce the overall charging expenses for fleets. We employ an ADMM-based algorithm to solve this optimization problem and use a nonlinear battery model for degradation analysis, considering the relationship between charging power and battery degradation costs. Through a comparative analysis of three charging strategies—Greedy Charging, Minimal Energy Charging, and Balanced Charging—the results show that the Balanced Charging strategy is the most effective. It not only reduces battery degradation costs but also controls aggregator demand, relieves grid pressure, and achieves an optimal balance between cost and battery lifespan.