Performance characteristics of a novel heat pipe-assisted liquid cooling system for the thermal management of lithium-ion batteries

Lithium-ion (Li-ion) batteries have been considered as the most promising energy storage devices for electric vehicles. An efficient battery thermal management system (BTMS) should be developed for the performance and life cycles of the batteries. The objective of this study is to analyze the thermal performance of a novel liquid cooling system combined with heat pipes for Li-ion batteries under various operating conditions and design parameters. A transient thermo-fluid simulation is developed to analyze the cooling performance characteristics of three BTMSs: (1) liquid cooling (LC), (2) liquid cooling with A-type heat pipes (LCA), and (3) liquid cooling with B-type heat pipes (LCB). The LCB shows a much higher performance than the LC, owing to the increased heat transfer area. The effects of the discharge rate, liquid mass flow rate, liquid temperature, and ambient temperature on the cooling performances of the BTMSs are investigated. The figure of merit is analyzed for various BTMSs with respect to the discharge rate and liquid mass flow rate. Additionally, the effective thermal conductivity of the heat pipe and thermal conductivity of the battery cell are analyzed to provide design guides. Finally, the cooling performance of the BTMS with the optimized design parameters is compared to that under basic conditions. The maximum temperatures of the battery module in the LCB decrease by 6.1 degrees C and 9.4 degrees C under the basic and optimized conditions relative to those in the LC, respectively.