Design And Implementation Of A Digital Twin System Of Lithium Battery For Mobile Energy Storage Power

Fossil fuel resources are insufficient,and can no longer meet the needs of contemporary automobiles,and the polluted gas environment produced by the combustion process causes great harm to the environment.Battery Management System(BMS)is a key technology in its research.The current BMS has several problems that need to be solved urgently:the embedded system has limited computing capacity;limited data storage capacity;unable to achieve precise SoC management and so on.Aiming at solving the problems of BMS,this subject proposes a battery system based on digital twin(DT)technology.An algorithm for online joint estimation of SoC is proposed,and the superiority of the algorithm is verified through experiments,and it is used for online SoC estimation of battery system.A set of DT battery system is designed and developed to realize system visualization and online monitoring of status.The system can solve the problems of BMS,provide ideas for the further development of BMS,and pave the way for the application of DT technology.The main research work of this paper includes:(1)The framework of battery system based on DT technology is established.According to the characteristics of the DT and the function of the BMS,the composition and functional modules of the system are determined:physical space,twin space and twin data.(2)Based on the conclusions of the literature and the experimental results obtained in this subject,the 2-RC equivalent circuit model is determined to be the battery physical model.The Forgetting Factor Recursive Least Square(FFRLS)is used for online model parameter identification.Then,an algorithm for joint estimation of SoC is proposed,and the superiority of the algorithm is verified by the Beijing Electric Bus Dynamic Test(BBDST)operating conditions.(3)A DT battery system is established.The selection of battery,motor and BMS acquisition board is confirmed,and the physical space of the DT system is built.The joint estimation algorithm is selected for online estimation of the battery SoC.3DsMax is used to draw a 3D visualization model which imported into Unity3D for scene drawing.Then,system visualization and SoC online monitoring are realized,and the twin space of the system is successfully built.Sqlserver is selected as the storage database to complete the data storage of the physical space and the twin space.The communication and testing of the system are carried out to realize the connection between the twin physical space,the twin data and the twin space,and the joint debugging of the entire system was successfully completed.