Performance simulation of a heat pipe and refrigerant-based lithium-ion battery thermal management system coupled with electric vehicle air-conditioning

Abstract

• A study is conducted on a novel heat pipe and refrigerant-based BTMS. • System performance is evaluated in temperature distribution, energy, and exergy. • Effect of different preset temperatures of the battery module is analyzed. • The performance optimization direction of the BTMS is pointed out. A battery thermal management system (BTMS) is crucial to ensure the safety and efficiency of electric vehicles (EVs). With the increase of battery energy density and the development of fast charging technology, a more compact and controllable BTMS is imperative for EVs to alleviate the thermal issues. In this study, a novel heat pipe and refrigerant-based BTMS coupled with an air-conditioning system is proposed for a battery module. The battery temperature distribution, energy efficiency, and exergy efficiency of the BTMS are numerically investigated under different ambient temperatures and battery heat generation rates. Besides, the effect of different preset temperatures of the battery module on the performance of the BTMS is explored. The results indicate that the maximum temperature of the battery module can be controlled at the preset temperatures (25 °C, 30 °C, and 35 °C), and the temperature difference among battery cells can be well guaranteed within 3 °C. Besides, increasing the preset temperature can improve the energy efficiency and exergy efficiency of the BTMS. When the preset temperature is increased from 25 °C to 30 °C and 35 °C, the average coefficient of performance increased by 16.95% and 38.41%, respectively; and the average exergy efficiency of the BTMS increased by 2.63% and 5.07%, respectively. Further, reducing the superheat at the outlet of the refrigerant pipelines and using a more efficient compressor are recommended to improve the performance of the BTMS. This paper aims to provide insights to the design and optimization of the BTMS in EVs.