Numerical modeling for aging investigations of lithium ion batteries

Abstract

Lithium-ion cells have higher energy, power density, and cycle life and newlinelower cost than other chemistries. Investigations are needed to simplify the use newlineof lithium-ion cell stacked battery packs with battery management systems newline(BMS). BMS senses temperature, current, and voltage and provides state of newlinecharge (SoC) and state of health (SoH) to users. Noises from sensing devices newlinecan cause errors in measurements for larger stacked cells in battery packs. BMS newlineengineers certainly use equivalent circuit model ECM and state estimation newlinetechniques to address this issue. newlineBased on literature findings, the use of composite electrodes and allied newlineparameters for lithium ferrous phosphate cells was extracted. Physics-based newlinemodeling (PBM) using single particle model (SPM) and pseudo-2-dimensional newlinemodel (P2D) methods were performed with COMSOL Multiphysics for 0.5, 1, newlineand 2 C ratings. The SPM discharge study, along with the thermal parameters newlineof the cell, was evaluated using the Newman, Tiedemann, Gu, and Kim (NTGK) newlinemethod with ANSYS. An actual model using model order reduction (MOR) newlinetechniques was modeled using the Galerkin Krylov method for minimal newlinecomputation efforts with maximum accuracy. newlineNumerical and experimental studies of cell degradation mechanisms newlinewere performed using PBM (SPM) with FEM. A transfer function was derived newlineto study the growth of cell impedance by chemical kinetics parameters. The newlineelectrochemical impedance (EIS) characteristics of the cell were investigated newlinethrough simulation and experimental studies using Nyquist and Bode plot newlineanalysis. The developed transfer function was reduced using Padé newlineapproximation to minimize nonlinearities. The chemical mechanical stress newlineanalysis was carried out using the COMSOL SPM model to evaluate the lithium newlineconcentration in a cell under applied pulse voltage newline