Numerical Investigation of the Thermal Performance of a Lithium-Ion Battery Pack Cooled by Nanofluid in Wavy Channels

Thermal management of lithium-ion batteries plays a vital role in enhancing the lifespan and safety of electric vehicles. This research presents a numerical simulation of thermal management for a ten-cell lithium-ion battery pack using intercellular wavy channels and nanofluid flow, conducted with COMSOL Multiphysics 6.4. The effects of inlet fluid velocity (1 to 4 mm/s), nanoparticle volume fraction (0 to 2%), number of inlet ports (1 to 3 inlets), and discharge rate (2 C to 4 C) on the thermal behavior of the system were investigated. The findings indicated that increasing the inlet velocity reduces the maximum outlet temperature from 308 K to 300 K. Moreover, the addition of 2% nanoparticles mitigates the peak temperature rise of the battery by 5%, due to enhanced thermal conductivity. Among the variables, increasing the number of inlets to three ports proved to be the most effective strategy; it reduced the maximum battery temperature from 313 K in the single-inlet configuration to 307 K, while boosting the convective heat transfer coefficient by 68%, reaching 32 W/(m²·K). This multi-inlet structure also provided better temperature uniformity. The results indicate that the designed system is capable of maintaining the pack temperature within a safe operating range even at high discharge rates, by adjusting the flow velocity and nanoparticle concentration.