Batteries (Aug 2023)

SOC Estimation Methods for Lithium-Ion Batteries without Current Monitoring

  • Zhaowei Zhang,
  • Junya Shao,
  • Junfu Li,
  • Yaxuan Wang,
  • Zhenbo Wang

DOI
https://doi.org/10.3390/batteries9090442
Journal volume & issue
Vol. 9, no. 9
p. 442

Abstract

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State of charge (SOC) estimation is an important part of a battery management system (BMS). As for small portable devices powered by lithium-ion batteries, no current sensor will be configured in BMS, which presents a challenge to traditional current-based SOC estimation algorithms. In this work, an electrochemical model is developed for lithium batteries, and three methods, including the incremental seeking method, dichotomous method, and extended Kalman filter algorithm (EKF), are separately developed to establish the framework of current and SOC estimation simultaneously. The results show that the EKF algorithm performs better than the other two methods in terms of estimation accuracy and convergence speed. In addition, the estimation error of the EKF algorithm is within ±2%, which demonstrates its feasibility.

Keywords