Cell selection and thermal management system design for a 5C-rate ultrafast charging battery module

In the pursuit of ultrafast charging electric vehicles, cell selection and thermal management play a critical role. This work explores the selection of a suitable battery cell, design of a battery module thermal management system, and thermal modelling of the cells and module. Four different cells are compared, each with unique characteristics that present advantages and disadvantages for ultrafast charging. The cells are first characterized in a lab, and their suitability for ultrafast charging is evaluated based on the experimental results. Factors such as charging efficiency and required cooling system size are also considered. Simplified thermal models are used for comparison of the different cells. A three-cell, liquid-cooled test module is designed and constructed for a selected cell, and detailed fluid and thermal models are developed for the module. Module temperatures at steady state and over time—during a series of fast charges and over a repeated driving and fast charge cycle—are simulated and compared to lab measurements. For a 5C charge, a peak temperature of 34.6°C is measured in the lab, and modelled within 0.6°C.