Minimization of thermal non-uniformity in lithium-ion battery pack cooled by channeled liquid flow

Abstract

In this work we conduct a numerical study with the aim of analyzing the effectiveness of cooling channels to reduce thermal non-uniformity in lithium-ion battery packs of electric vehicles. Particular approaches toward zero or near-zero thermal non-uniformity in lithium-ion battery packs are proposed and their performance and viability are evaluated through numerical simulations. Battery packs cooled by liquid flowing in serpentine channels are used to illustrate the proposed approaches. A thermal model, which has been extensively tested, is applied to a battery module of 71 18650-type NMC (nickel-manganese-cobalt) batteries. In particular, among several approaches, two of them show considerable promise in improving the pack thermal uniformity, namely: (a) shortened flow paths by using multiple serpentine channels, and (b) increasing contact areas between the batteries and the serpentine channel along the flow path in the streamwise direction. The results of the numerical simulation indicate that these two particular approaches can reduce the thermal non-uniformity of the battery module under 5C discharge operations to values lower than 2.2 K and 0.7 K, respectively. The description, functional feasibility and effectiveness of these approaches are extensively covered in the present work.