Temperature-Controlled Smart Charging for Electric Vehicles in Cold Climates

TL;DR

This work tackles the challenge of EV charging in cold climates by integrating battery heating into day-ahead smart charging at solar-powered stations. It develops a battery temperature control model and a temperature-sensitive charging scheme, and demonstrates scalable computation via reduced-order dual decomposition and vehicle rescheduling. Case studies show significant charging-cost reductions ($12.5\%$–$18.4\%$) and lower overhead heating energy ($0.4\%$–$6.8\%$), with improved rooftop PV utilization and climate resilience. The approach has practical implications for EV microgrids by enabling coordinated heating and charging to exploit thermal inertia and renewable energy availability.

Abstract

The battery performance and lifespan of electric vehicles (EVs) degrade significantly in cold climates, requiring a considerable amount of energy to heat up the EV batteries. This paper proposes a novel technology, namely temperature-controlled smart charging, to coordinate the heating/charging power and reduce the total energy use of a solar-powered EV charging station. Instead of fixing the battery temperature setpoints, we analyze the thermal dynamics and inertia of EV batteries, and decide the optimal timing and proper amount of energy allocated for heating. In addition, a temperature-sensitive charging model is formulated with consideration of dynamic charging rates as well as battery health. We further tailor acceleration algorithms for large-scale EV charging, including the reduced-order dual decomposition and vehicle rescheduling. Simulation results demonstrate that the proposed temperature-controlled smart charging is superior in capturing the flexibility value of EV batteries and making full use of the rooftop solar energy. The proposed model typically achieves a 12.5--18.4% reduction in the charging cost and a 0.4--6.8% drop in the overhead energy use for heating.

Figures (8)

• Figure 1: The first dates of a freezing median temperature across the U.S. mainland. The warm southern and coast regions may also experience sub-freezing temperature in November. The source data and graphic visualizations come from the U.S. national weather service.
• Figure 2: An illustrative smart charging station that supports charging and thermal management coordinately as a local microgrid. The rooftop solar panels and grid connection are available in this station system as well.
• Figure 3: Illustration of the complicated couplings between four key decision variables from the thermal and energy management. All coupling arrows are marked with the associated formula (constraint) label in the main text.
• Figure 4: A Sankey diagram for electric and heating energy flows. Different energy transfer and transition processes are expressed as branch flows.
• Figure 5: Heating and charging power limits under different temperature conditions. The temperature dependence is clear and the adverse consequences emerge as the temperature goes down below 15°C.