Thermal Performance Analysis of Liquid Cooling System in Lithium-ion Battery

Abstract

Electric vehicles (EV) have been rapidly developing and are becoming increasingly popular due to its zero emission, low operating cost and noise free. However, there are some factors that limit the development of electric vehicles, such as the thermal performance, cost, lifetime and safety of the battery. To address this difficulty integration of liquid cooling system is the promising solution. The battery cooling technologies like air cooling system, liquid cooling system, direct refrigerant cooling system, phase change material (PCM) cooling system are used in e-vehicle. In this research, the main goal is to better understand how to improve the consistent temperature distribution in battery packs. The study provides general strategies to reduce thermal unevenness or achieve almost no differences in temperature within lithium-ion battery modules. These modules are cooled using channelled liquid flow, where a liquid circulates through channels designed for thermal management. To demonstrate the effectiveness of the proposed strategies, the research numerically analyzes two cases: one with multiple short channels and another with orderly magnified contact areas. Two of the methods demonstrate significant improvement in the overall thermal uniformity of the battery pack.(a) Shortening flow paths with multiple serpentine channels, and (b) enhancing contact areas between batteries and serpentine channels along the flow path in the stream wise direction, both show considerable promise in improving pack thermal uniformity.The study investigates the thermal effects of varying liquid flow rates in a computational fluid dynamics model for an 71 18,650 battery pack discharged at 5C. A three-dimensional model is built in ANSYS and the mesh is generated using Fluent Meshing. The maximum temperature differences observed across the battery module during a 5C discharge are 2.2 K for one strategy and 0.7 K for the other. This information highlights the effectiveness of the second strategy in achieving lower temperature variations, indicating better thermal uniformity during the discharge process compared to the first strategy.