Equivalent Modeling and Parameter Identification

Abstract

This chapter mainly introduces four equivalent circuit models and parameter identification methods and briefly introduces three commonly used battery operating conditions. The Rint model is a relatively simple model; since the model does not consider the polarization characteristics of the battery, the accuracy of the model is low, which is rarely seen in practical applications. Compared with the Rint model, the Thevenin equivalent circuit model is not only simple in structure but also able to meet the simulation requirements, so the battery Thevenin equivalent circuit model is often used in practical applications. The partnership for a new generation of vehicle (PNGV) model covers the characteristics of battery polarization and ohmic resistances; the PNGV equivalent circuit model is more accurate. The second-order equivalent model introduces an RC series network and a second-order RC parallel network. Compared with the Thevenin model and the PNGV model, the accuracy of the model has been improved, which can simulate the ohmic polarization, electrochemical polarization, concentration polarization, and self-discharge effects. At the same time, offline parameter identification and online parameter identification are introduced to provide a basis for follow-up work.