A Compact Hybrid Battery Thermal Management System for Enhanced Cooling

Hybrid battery thermal management systems (HBTMS) combining active liquid cooling and passive phase change materials (PCM) cooling have shown potential for the thermal management of lithium-ion batteries. However, the fill volume of coolant and PCM in hybrid cooling systems is limited by the size and weight of the HBTMS at high charge/discharge rates. These limitations reduce convective heat transfer from the coolant during discharge, accelerating the liquefaction rate of PCM and reducing passive cooling effects. This paper proposes a compact hybrid cooling system with multi-inlet U-shaped microchannels, embedded with PCM/aluminum foam for compactness. Additionally, nanofluid cooling (NC) technology, which has better thermal conductivity, is utilized. A pulsed flow function for enhanced cooling with reduced power consumption is developed. An experimentally validated thermal-fluid dynamics model optimizes operating conditions, including coolant type, cooling direction, channel height, inlet flow rate, and cooling scheme. The results indicate that the hybrid cooling solution of NC+PCM+EC used in HBTMS reduces the maximum temperature of the lithium-ion battery by 3.44°C under a discharge rate of 1C at a room temperature of 25°C, with only a 5% increase in power consumption compared to conventional liquid cooling methods for electric vehicles. The average number of battery charges has increased by about 6 to 15 percent, which can enhance the range as well as driving safety of new energy EV.