A refrigerant-based thermal management system for a fast charging process for lithium-ion batteries

The effective fast-charging power (≥100kW) is inevitable to extend the driving range of battery electric vehicles. Nevertheless, lithium-ion batteries suffer from high-heat generation at these high-current charging rates. Hence, a proper thermal management system (TMS) is urgently needed to address this issue. In this paper, a refrigerant-based TMS has been simulated for a fast-charging regime (5C or 115A) of a lithium-ion titanate battery pack. To investigate the benefits of the refrigerant-based TMS in battery electric vehicles, the model is built in Simcenter AMESim to simulate the battery cooling system and its transient interaction with the heat pump system during a current profileA liquid cooling system is developed in the chiller coolant loop which is integrated with an accumulator, a compressor, a condenser, and an electric expansion valve.. Results show that adding a refrigerant-based TMS to cool down the lithium-ion battery pack under a fast-charging scenarios can control the temperature in the desired range (below 45°C). According to the simulation results, during the fast charging process, the battery pack temperature starting at 25°C reaches to 40.2 °C, which leads to decay of the battery pack’s lifetime. Considering the refrigerant-based TMS during the fast-charging process, the temperature of the pack is controlled at 28.8 °C, which shows that by employing the proposed TMS, 28% improvement can be achieved.

Trefwoorden:Lithium-ion battery, Thermal management system, Refrigerant cooling, Fast charging, State of charge (SoC)