Electric Vehicle Battery Thermal Management Using Liquid Cooling

Abstract

The contents of this thesis are the culmination of the research and studies sparked by therapid growth in the field of electric vehicles (EVs) and lithium-ion batteries. The first few sections (Chapters 1-3) gives an introduction and highlighted the research performed on the topic, from commercial to research and development (R&D). First, a synopsis of the most popular commercialized EVs on the market is given with emphasis on battery type, orientation, and battery thermal management system (BTMS). Next, brief reviews on liquid-cooled papers pulled from the R&D side are covered, organized by numerical and experimental studies, as well as the type of cooling (indirect single-phase, indirect two-phase, direct single-phase, and direct two-phase). Chapters 4-5 features a direct single-phase study for an abridged half-cell battery module design based on an optimal tube bank arrangement. The study was modeled and simulated in COMSOL Multiphysics comparing different 3M™ dielectric fluids, water, and water-glycol with varying longitudinal, transverse, and diagonal pitch lengths. Results showed that FC-3284 was the most effective in maintaining proper operating temperatures of less than 40°C for lithium-ion batteries, but at the slight expense of increased pressure drop and pumping power. Changing the spacing between batteries also had an effect on maximum temperature, pressure drop, and pumping power. The 0.75x ST set-up had the lowest maximum temperature values and the 0.75x SL set-up had the lowest pressure drop and pumping power requirements.