An improved state-of-charge estimation method for sodium-ion battery based on combined correction of voltage and internal resistance  

作　　者：Yongqi Li Cheng Chen Youwei Wen Qikai Lei Kaixuan Zhang Yifei Chen Rui Xiong 

机构地区：[1]Energy Storage Research Institute,China Southern Power Grid Power Generation Co.,Ltd,Guangzhou 510663,China [2]School of Mechanical Engineering,Beijing Institute of Technology,Beijing 100081,China [3]State Key Laboratory of Fire Science,College of Resources and Environ-ment,University of Science and Technology of China,Hefei 230026,China

出　　处：《iEnergy》2024年第3期128-134,共7页电力能源汇刊（英文）

基　　金：supported by the Key Science and Technology Project of China Southern Power Grid Corporation:Sodium-ion Battery Energy Storage System Multi-Scenario Demonstration Application Project-Topic 2 Research on Safety Application Technology of Sodium-ion Battery Energy Storage(STKJXM 20210104);the National Natural Science Foundation of China under Grant 52307233.

摘　　要：ABSTRACT The accurate state-of-charge(SOC)estimation of sodium-ion batteries is the basis for their efficient application.In this paper,a new SOC estimation method suitable for sodium-ion batteries and their application conditions is proposed,which considers the combination of open circuit voltage(OCV)and internal resistance correction.First,the optimal order of equivalent circuit model is analyzed and selected,and the monotonic and stable mapping relationships between OCV and SOC,as well as between ohmic internal resistance and SOC are determined.Then,a joint estimation algorithm for battery model parameters and SOC is estab-lished,and a joint SOC correction strategy based on OCV and ohmic internal resistance is established.The test results show that OCV correction is reliable when polarization is small,that the ohmic internal resistance correction is reliable when the current fluctuation is large,and that the maximum absolute error of SOC estimation of the proposed method is not more than 2.6%.

关 键 词：Sodium-ion battery equivalent circuit model parameter identification state of charge joint estimation 

分 类 号：TM9[电气工程—电力电子与电力传动]