Lithium-ion Battery Modeling Using Equivalent Circuit Model

Abstract

With modern technologies, most devices such as electric vehicles are powered by lithium batteries. This kind of battery is advantageous to other types of batteries, such as higher energy density, reliability, etc. to work effectively, it is necessary to handle them using a battery management system BMS, which guarantees their safety and optimizes their performances in normal conditions. One of the things that a BMS must do is to estimate the state of charge SOC of the battery because it is the most critical indicator of battery state. This task is very challenging because the lithium-ion battery is a highly time-invariant, nonlinear, and complex electrochemical system. In this paper, we present a cell model that can be used in the state of the charge estimation process. This model is based on an electrical approach where we build an electrical circuit that has the same behavior as the real cell, this approach is called the Equivalent circuit model ECM. using a set of laboratory data, we will determine the model parameters using multiple techniques. Those parameters will be used in process of estimating the state of charge and other internal parameters.