Thermal management of 3D lithium-ion pouch cell under fast discharging: a multi-scale multi-domain (MSMD) framework with phase change material, nanoparticle and metal foam

Abstract

Lithium-ion batteries, a vital power source to electric vehicles, are highly sensitivity to temperature fluctuations. An effective thermal management is therefore essential to prevent overheating during charging and discharging, ensuring safety, reliability, longevity, and optimal performance. This study adopts a single 3D pouch lithium-ion cell cooled by a novel phase change material (PCM) configuration under various ambient conditions. The cooling performance was examined at discharge rates of 3C-7C for different convective heat transfer coefficients (h = 5-15 W/m²K) and PCM encapsulation thicknesses (1-3 mm) employing the Multi-Scale Multi-Dimensional (MSMD) model. At 7C discharge rate, using 1 mm PCM effectively mitigates temperature rise across various models. Notably, at 5C and ambient temperature of 300 K, employing n-octadecane (PCM1) of 1 mm, 2 mm, and 3 mm thicknesses result in substantial reductions in the maximum temperature by 12.3 K, 16.4 K, and 16.7 K, respectively, compared to PCM-absent systems. For fixed amount of PCM, PCM-fin models (Models 2 and 3) predict reduced temperature drops up to 2.5 K at 7C compared to Model 1. Additionally, the local thermal equilibrium model was employed for the composite PCM utilizing n-octadecane (PCM1) and n-eicosane (PCM2) with Cu metal foam featuring 90% porosity and 30 pores per inch (PPI), alongside nano-PCM cooling. Introducing Cu metal foam improves thermal uniformity within the cell, with maximum temperature reduction of 1.4 K for composite PCM2 compared to PCM2 alone. Furthermore, the conditions of external and internal short circuits are also investigated to comprehensively evaluate the battery safety and performance.