Analysis of Simplified Electrochemical Model for Lithium Battery in Electric Vehicles

Abstract

The study simplifies the application of the electrochemical model of lithium-ion battery in battery experiments and applies it to the battery management system (BMS), which can improve the validity and accuracy of the BMS for battery state estimation. Based on the charge-discharge experiments of 18650 lithium-ion battery, two simplified models are established, namely single-particle model (SP) and extended single-particle model (ESP). The research process consists of three parts: (1) the characteristics of lithium batteries under different discharge rate conditions are tested. (2) Based on the experimental results, the parameters of the two simplified models are estimated with particle swarm optimization (PSO). (3) Two simplified models are analyzed and compared using MATLAB. The results demonstrate that both simplified models can accurately predict the experimental results of 18650 lithium-ion batteries, but the effect of the ESP model is better.