Optimal design of liquid cooling structure with bionic leaf vein branch channel for power battery

Abstract

• ·The liquid cooling plate with BLVB channel for Li-ion battery is proposed. • ·The BLVB cooling system is conducted by using 16 orthogonal test schemes. • ·The liquid cooling influence factors are analyzed by using the range method. • ·Multi-parameter coupling of the liquid cooling plate is optimized based on NSGA-II. Effective thermal management is crucial for the thermal safety and uniformity of lithium-ion(Li-ion) batteries caused by high temperature. However, it is challenging for structural design and optimization method of cooling system especially considering dynamic heat generation of the battery. The liquid cooling plate with the bionic leaf vein branch(BLVB) channel which is sandwiched with a pouch Li-ion battery was proposed. The effects of multi-parameter coupling with inlet flow rate( M ), channel width( D ), channel angle( α ) and channel number( N ) of the cooling plate on the maximum temperature( T max ), the maximum temperature difference(Δ T max ) of battery and the average pressure drop of coolant(Δ P avg ) were investigated by using the orthogonal test range method. Based on the non-dominated sorting genetic algorithm-II(NSGA-II), the solution sets were optimized. Results show that the proposed BLVB channel is efficient for battery cooling. Even at 3C discharge, T max can be controlled within 33.34℃. Meanwhile, M and D are the main factors affecting the cooling performance, α and N are the secondary factors. However, with the increasing of α or the decreasing of N , T max and Δ T max are decreased due to the enhancement of backflow or vortexes near the outlet. The optimal results are T max =30.31℃, Δ T max =2.78℃ and Δ P avg =0.50kPa; while the optimal parameters are M= 0.10m/s, α= 159°, N= 15 and D= 2.60mm. Compared with the initial BLVB channel and the traditional parallel straight channel, T max with the optimum BLVB channel can be reduced by 0.23℃ and 1.12℃ respectively when M= 0.10m/s. The corresponding Δ T max is declined by 0.28℃ and 1.64℃, and Δ P avg is decreased by 65.56% and 8.77% respectively. The proposed BLVB channel can be used to provide a certain reference for the thermal design of battery liquid cooling system.