Thermal Modeling of a Lithium-Ion Battery Pack in a Plug-in Hybrid Electric Vehicle

Abstract

This paper presents thermal modeling of a lithiumion battery pack to be used in a Plug-in Hybrid Electrical Vehicle (PHEV). The battery pack consists of eight modules (totally 96 prismatic cells) cooled by circulating 50/50 ethylene glycol-water mixture in a cold plate. Three cases, e.g., (a) battery heating up from -30 ˚C environment, (b) high-speed ramping in pure electrical driving mode, and (c) NEDC cycle in pure electrical driving mode, were modeled using a 1D simulation software. To study the internal temperature variation inside modules, each battery module was further decomposed into three nodes in the height direction, showing 5-8 ˚C temperature variation. We also conducted CFD to study the fluid flow and heat transfer in the cold plates, and the results are in great agreement with theoretical predictions. The work provides deep insight of thermal physics and can greatly help thermal design of the battery pack.