Thermal performance analysis of battery modules with passive cooling under different cycling loads in electric vehicles

This study investigates the impact of passive cooling for battery thermal management systems (BTMS) for various configurations of modules under different load scenarios (e.g., continuous cycling and five automotive drive cycles). Numerical computational fluid dynamics (CFD) is used to analyse the effect of passive cooling in the form of circumferential phase change material (PCM) jackets for each cell. The three-dimensional (3D) modules of a 24-battery cell arranged in 24S, 2P12S and 3P8S in the presence and absence of latent heat (LH)/PCM jackets were constructed (in combined 6 different modules considered). The constructed modules were simulated under 1C continuous cycling (as a theoretical cycling) and five actual drive cycles (from a harsh one to a casual one including US06, LA92, NN, UDDS, HWFTa). The performance of the proposed modules under the discussed loads is investigated against battery module temperature, PCM liquid fraction, state-of-charge (SOC) and passive zone potentials. The study concludes the effectiveness of passive cooling (in the forms of latent heat jackets) to stabilise the system temperature as well as individual cells under normal and harsh Cases. Results indicated that the natural convection cooling LH jackets maintained stable and uniform temperatures for all cycles with a reduction in module temperature on average by 20 °C and less than a 5 °C temperature difference. There was on average over 200 % improvement in battery useful life under all drive cycles assessed regardless of module arrangements.