Thermal Management of Lithium Ion Cells at High Discharge Rate using Submerged-Cell Cooling

Abstract

Thermal Management of automotive Li-ion battery packs is crucial for its safe and efficient operation. Indirect liquid cooling strategy using a cold plate or cooling channels is commonly employed for the thermal management of the battery modules and packs by Electric Vehicles. Although such a cooling strategy provides improved heat transfer compared to air-cooling, it is not sufficient for high performance applications (C-rate >2C) and introduces higher temperature gradients along the length of a cell. This effect is more pronounced for cylindrical format Li-Ion cells. Through a cell-level study, the current article explores the submerged-cell cooling technology that allows direct heat transfer from the cell to a flowing dielectric coolant for high performance applications. Results show that submerged-cell cooling technology effectively reduces both cell temperatures and thermal gradients on a 21700 cylindrical cell even at high C-rates. The analysis is performed using 3D time-accurate CFD simulations in STAR-CCM+ and validated by comparing with experiments.