Eventos Anais de eventos
ENCIT 2022
19th Brazilian Congress of Thermal Sciences and Engineering
An initial study on an EV battery prismatic cell thermal behavior
Submission Author:
Luciano Amaury dos Santos , SC
Co-Authors:
Luciano Amaury dos Santos, Joaquim Manoel Gonçalves, Samuel Luna de Abreu, ANDRE LUIZ FUERBACK, Daniel Godoy Costa, ADRIANO DE ANDRADE BRESOLIN
Presenter: Luciano Amaury dos Santos
doi://10.26678/ABCM.ENCIT2022.CIT22-0075
Abstract
Even dismissing its impact on global warming, air pollution due to IC engines in large cities is an important problem to which electrical vehicles (EVs) have been a very attractive solution. The relatively low thermodynamic efficiency of small IC engines when compared to the combination of big electric power plants and electrical motors also have pushed the engineers to the EV development at each Oil crisis. Historically the lack of adequate and accessible ways of storing electrical energy has made EV wide adoption unviable, but the fast advance in batteries technology over the last decades really created a new scenario, in which government regulations, along people enthusiasm, ensued a blossoming of EVs production and even conversion of IC engine powered vehicles into EVs. In this context the Electrical Mobility Laboratory (EMoL) was created at the IFSC. Reports on battery degradation and fire, along with the appreciation of the efforts of big car manufacturers towards battery thermal management, turned the attention of the EMoL team to the battery cell thermal behavior. It is a relatively recent concern for the team, as their first prototypes had cells exposed to the environment air that readily kept the temperatures under proper limits. The prospect of putting these cells in a sealed battery pack and offering it as part of a conversion kit (to be used at more challenging environmental conditions and power demands) triggered this initial study of battery cells thermal behavior. This study aims to support a more comprehensive electrothermal model discussed in a companion paper. The initial study reported here deals with basic heat transfer, initially in a single prismatic cell, using an analytical solution of three dimensional heat conduction to discuss the practical application of lumped capacitance analysis in some circumstances. The orthotropic properties used to model the multilayered cells as a single continuous medium brought the necessity of adapting the effective heat transfer coefficient calculation (used to extend lumped capacitance analysis applicability) to orthotropic media (something not existent in the literature, to the best of authors' knowledge). A coarse grid CFD solution is used for some qualitative analysis and a quick discussion of simple heat transfer models for a battery of cells cooled by air and by conduction is made, highlighting the first mistakes likely to occur in such studies and lessons already learned.
Keywords
Battery cell, Lumped analysis, Orthotropic conduction
