A novel nanofluid cooling system for modular lithium-ion battery thermal management based on wavy/stair channels

An innovative liquid cooling system that contains stair and wavy channels by alumina nanofluid with copper sheath is numerically analyzed to improve the battery thermal management system's temperature distribution and cooling capacity during discharge/charge processes. The effects of the charge/discharge current rate, alumina nanofluid coolant, inflow velocity, ambient/fluid inflow temperature, stair channel, interfacing regions between adjacent LIBs, and the contact regions between LIBs and wavy channel shell on the thermal efficiency of the battery module was investigated. Based on the outcomes, it is concluded that the addition of coolant alumina nanofluid with a 2% volume fraction notably reduces the highest temperature and temperature non-uniformity across the battery module. Simulation results illustrated that by using a 2% volume fraction of Alumina nanofluid, the peak temperature and temperature difference for the discharge process decreased 1.2 °C and 0.4 °C, compared to DI water, respectively. In addition, increasing the coolant inlet velocity led to a decrease in maximum temperature and temperature difference. Different ambient/fluid inflow temperatures of the battery module are evaluated to simulate different weather climates. An innovative design using the stair channel cooling is finally developed for the LIB thermal management system. Comparing the two stair and straight channels, it is accomplished that the temperature non-uniformity for the stair-type channel is almost reduced by 0.19 °C and 0.22 °C for the discharge and charge processes, respectively.