Rapid SOC Estimation Analysis of Series Lithium Battery Based on Improved Second-order Model
The most commonly used circuit model for lithium-ion batteries is the second-order RC equivalent circuit model.Its parameter identification requires too many parametersand the state of charge(SOC)equation estimation involves complex exponential calculation.Therefore,an improved second-order battery model integrating the RLS parameter identification and linear KF method to implement joint SOC estimation is designed to facilitate real-time SOC estimation of multiple series lithium batteries.To ensure that the system meets the SOC estimation accuracy and is able to obtain faster processing rate,the RLS and KF algorithm are used to achieve SOC estimation.The results show that compared with the second-order RC model,the improved second-order model results in a smaller MRE,a smaller overall error,and significantly shortens the algorithm processing time,with stronger overall performance.When implementing SOC joint estimation,more accurate SOC estimation results are obtained,the SOC estimation rate is faster,and the comprehensive performance of the algorithm is significantly improved.This research helps improve the service life of lithium batteries.
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