Liquid Cooling of Li-Ion Cells Based on a Constructal Canopy-To Approach

Abstract

While many countries ambition to transition to clean energy, challenges appear related to the new developed technologies. This is particularly the case when it comes to electric vehicles and their batteries. The technology of the latter is based on Lithium-ion electrochemical reactions. During the batteries discharge, the electrochemical reactions are exothermic, and they are endothermic during the charging phase. The large change in temperature threatens the life duration of the batteries, and when combined to other factors, their safety. Therefore, the thermal management of the electric vehicle battery pack is a critical aspect that requires specific attention. In this paper, we present the work conducted by our group on thermally efficient solutions for maintaining the battery cells within the temperature range expected by manufacturers. The thermal management solution consists in inserting between the battery cells a constructal-based liquid cooling system. Such systems are called canopy-to-canopy architectures. The cooling fluid is driven from a trunk channel to perpendicular branches that make the tree canopy. An opposite tree collects the liquid in such a way that the two trees match canopy-to-canopy. The results indicate that such configurations allow to extract most of the non-uniformly generated heat by the battery cell during the discharging phase, while using a small mass flow rate. Furthermore, the configuration with 5 branches appears to be the one with high thermal efficiency and low pumping power.