A Coupled Lattice Boltzmann-Finite Volume Method for the Thermal Transient Analysis of an Air-Cooled Li-Ion Battery Module for Electric Vehicles with Porous Media Insert Modeled at REV Scales 2019-24-0242

Lithium ion batteries are the most promising candidates for electric and hybrid electric vehicles, owe to their ability to store higher electrical energy. As a matter of fact, in automotive applications, these batteries undergo frequent and fast charge and discharge processes, which are associated to internal heat generation, which in turns causes temperature increase. Thermal management is therefore crucial to keep temperature in an appropriate level for safe operation and battery wear prevention.

In a recent work authors have already demonstrated the capabilities of a coupled lattice Boltzmann-Finite Volume Method to deal with thermal transient of a three-dimensional air-cooled Li-ion battery at different discharging rates and Reynolds numbers. Here, in order to improve discharge thermal capabilities and reduce temperature levels of the battery itself, a layer of porous medium is placed in contact with the battery so to replace a continuum solid aluminum layer. Many studies, which have already demonstrated how the porous media can improve thermal performance of heat exchange systems, are present in recent literature. There is a large number of models for representing porous media, one can implement porosity effects directly on the resolved equations or precisely modeling the porous medium geometry. In this work, porous medium has been modeled at REV scales including characteristic effects directly on Navier-Stokes and energy equations. The use of a porous insert, rather than of a solid aluminum lamina, should improve capabilities of discharging the same amount of heat generated from the battery. More specifically, aluminum open cell metal foams are considered in this work, due to the large availability of literature data. The analysis will be carried out with varying porosity and pore per inch distribution at different Reynolds number so to highlight benefits which derive from such an insert. Results will be compared in terms of temperature profiles under different working conditions and referring to the original solution equipped with the solid aluminum lamina.