Comparison Of Lithium Ion Battery Model Parameter Identification Algorithms Based On Equivalent Circuit Model

With the continuous progress of science and technology and the increasing economic level of people,the new energy automotive industry has emerged and developed rapidly.Therefore,the research on the power battery has gradually deepened,especially for lithium-ion battery management system research.In the process of establishing a lithium-ion battery management system,one of the most fundamental and crucial steps is to establish an accurate and effective battery model and accurately identify the battery model parameters.In this paper,the equivalent battery model and its improved model of the lithium-ion battery as the research object is established,and the use of different parameter identification algorithms are deeply compared and studied.The main work is done as follows:(1)Based on the basic analysis of the research object lithium-ion battery and the analysis of the existing common lithium-ion battery model,the battery model structure used in this paper is established,which is based on the wide range of Thevenin models,a dual-polarized battery equivalent model is constituted by adding an RC circuit,and on this basis,a basic theoretical analysis of the equivalent model is performed.(2)Based on the constructed battery equivalent model,three parameters including forgetting factor recursive least square method,Bayesian identification algorithm and Kalman filter algorithm are used to identify the model parameters,and the realization of the identification algorithm is analyzed in detail.Matlab is used for programming simulation and after the contrasting of the identification results,it is found that the Kalman filter algorithm has faster identification speed,strong anti-interference ability and high precision than other algorithms,and the error is controlled within 2%;(3)For the most of existing battery models,experiments are needed to obtain the open-circuit voltage information.In this paper,a direct identification method of battery model parameters is adopted.The designed dual polarization battery equivalent model is improved,and the recognizability of the newly constructed model parameters is analyzed,and the parameters' identifiability of the model was verified.The nonlinear least squares method was used to identify the parameters based on the improved model.The parameters convergence and accuracy were compared with the first three algorithms.Comparing with the angle of complexity of the algorithm,it is found that the direct parameter identification algorithm based on the improved model has the advantages of fast convergence speed,high accuracy,low complexity,error control within 1.5%,and significant advantages and application prospects.