Review on Estimation Methods for State of Charge of Lithium-ion Battery and Their Application Scenarios

Accurately estimating the state of charge (SOC) of lithium-ion battery is an important measure to prolong the service life of vehicle lithium-ion battery, ensure the safety of charging and discharging of energy storage systems, and improve the reliability of uninterruptible power supply (UPS). The SOC estimation of lithium-ion battery has the characteristics of various method categories and diversified application scenarios, and has gradually become the focus of research. Firstly, the basic definition of SOC is expounded and many kinds of complex factors affecting SOC are analyzed. Secondly, the existing SOC estimation methods for lithium-ion batteries at home and abroad are investigated and summarized, and the advantages and disadvantages of various methods and the corresponding improvement directions are summarized. Then, the implementation cases and applications of SOC estimation methods for lithium-ion batteries are summarized in different scenarios such as vehicle lithium-ion battery, consumer electronics, power system energy storage and communication base stations, and the drawbacks of existing methods are analyzed. Finally, in view of the current research status of SOC estimation methods for lithium-ion batteries in multiple scenarios, the challenges and prospects of SOC estimation methods for lithium-ion batteries in the future are proposed from four aspects, which will provide reference for the follow-up research. © 2022 Automation of Electric Power Systems Press. All rights reserved.