Thermal management of prismatic lithium-ion battery using mist cooling with single and multiple injections: a numerical study

Thermal management of high-discharge prismatic lithium-ion battery packs remains challenging due to their large planar heat-transfer surfaces, strong streamwise thermal gradients, and stringent temperature uniformity requirements. This study numerically investigates mist-assisted air cooling as an enhancement to conventional forced air cooling for a high-discharge (5 C) prismatic LiFePO₄ battery pack. A transient three-dimensional CFD framework that incorporates detailed spray dynamics, droplet breakup, evaporation, and two-way phase coupling is employed to compare pure air cooling with single- and multiple-mist injection configurations. Results indicate that pure air-cooling leads to a peak cell temperature of approximately 62 °C, accompanied by significant thermal nonuniformity. Single mist injection reduces the maximum temperature by 2-3 °C but exhibits limited downstream effectiveness due to vapour accumulation. In contrast, multiple mist injection achieves a peak temperature reduction of nearly 10 °C with reduced non-uniformity in temperature. Vapour mass-fraction contours reveal that distributed injection sustains evaporation along the entire flow path, mitigates boundary-layer redevelopment, and ensures uniform latent heat absorption. Transient analysis further demonstrates improved thermal stability under sustained discharge. The findings establish multiple mist injection as a lightweight, energy-efficient, and effective cooling strategy for high-rate prismatic battery thermal management.