Numerical investigation of cooling performance of a novel air-cooled thermal management system for cylindrical Li-ion battery module

Abstract

Batteries strongly influence the performance of electric vehicles. Therefore it is crucial to develop a battery thermal system that is highly efficient in removing the battery pack's heat during its operation. In this paper, a numerical analysis of a lumped thermal model coupled with fluid flow equations is employed to investigate the novel air-cooled battery thermal management system (BTMS). The cooling efficiency of the proposed battery thermal system with commercial thermal interface material (3M™) is investigated by comparing it with a standard battery pack at different discharge rates. The proposed solution offers a 25% reduction in peak temperature when compared to the standard one. The thickness of the thermal interface material is found to have an insignificant impact on the battery pack's thermal performance. Introducing forced air-cooling in the battery pack reduced the maximum temperature considerably but increased the temperature difference compared to the battery pack without forced convection. Then the effect of various structural and operational parameters on the performance of the BTMS is investigated. Moving the air inlet-outlet boundaries to a central location increased the uniformity of temperature distribution in the battery pack. Although the increase in the inlet airflow velocity reduces the maximum temperature, it comes at the cost of an increase in temperature difference and power consumption. It is further observed that a reduction in ambient temperature reduces the peak temperature and makes the temperature distribution in the battery pack more homogeneous. The discharge voltage curves indicate a slight reduction in cell potential as a reducing function of temperature.