A comparative study between air cooling and liquid cooling thermal management systems for a high-energy lithium-ion battery module

Abstract

• A comparison between air-based and liquid-based BTMSs for a 48 V battery module. • Temperature difference within the module increases with an increase in air flow rate. • Better temperature uniformity is achieved by liquid cooling system. • The liquid cooling method is more energy efficient than air cooling. The parasitic power consumption of the battery thermal management systems is a crucial factor that affects the specific energy of the battery pack. In this paper, a comparative analysis is conducted between air type and liquid type thermal management systems for a high-energy lithium-ion battery module. The parasitic power consumption and cooling performance of both thermal management systems are studied using computational fluid dynamics (CFD) simulations. The 48 V module investigated in this study is comprised of 12 prismatic-shape NMC batteries. An experimental test bench is built up to test the module without any cooling system under the natural convection at room temperature, and the numerical model of the module is validated with experimental results. Two different cooling systems for the module are then designed and investigated including a U-type parallel air cooling and a new indirect liquid cooling with a U-shape cooling plate. The influence of coolant flow rate and coolant temperature on the thermal behavior of the module is investigated for a 2C discharge process. It was found that for a certain amount of power consumption, the liquid type BTMS results in a lower module temperature and better temperature uniformity. As an example, for the power consumption of around 0.5 W, the average temperature of the hottest battery cell in the liquid-cooled module is around 3 °C lower than the air-cooled module. The results of this research represent a further step towards the development of energy-efficient battery thermal management systems.