Mini-channel liquid cooling system for large-sized lithium-ion battery packs by integrating step-allocated coolant scheme

Abstract

• Three types of liquid cooling systems are explored for large-sized batteries. • The fully-covered cold plate enables a more even temperature distribution. • The cooling performance is seriously deteriorated for the battery packs. • The optimized approach employing the step-allocated coolant scheme is verified. To regulate the temperature spikes and temperature gradients of large-sized lithium-ion battery packs, the mini-channel liquid cooling systems are developed and numerically investigated in this study. Three design schemes are firstly analyzed and compared at the cell level based on a three-dimensional transient thermal model. It shows that design scheme 2 using the fully-covered cold plate and segmented centralized minichannels performs best. However, the cooling performance is seriously deteriorated at the module level. At the same flow rate of 2 × 10 −5 kg/s, the maximum surface temperature and temperature gradient increase from 34.79 °C and 4.12 °C to 49.61 °C and 14.34 °C when the cell number increases from N = 1 to N = 3. Finally, an optimized approach employing the step-allocated coolant scheme is conceived, with which the maximum surface temperature and the largest temperature difference of the 3S1P pack can be controlled at 33.38 °C and 4.56 °C over the 5C discharge process. The research results suggest that the mini-channel liquid cooling system integrating the step-allocated coolant scheme can be a new approach for the thermal management of large-sized battery packs.