| Electric vehicle,as an important direction of vehicle transformation under the background of energy crisis,has been experienced more than ten years of development,and various technologies have made great breakthroughs,but there are still many problems to be solved.Lithium battery is widely used as power battery in electric vehicles,and it is equipped with battery management system(BMS),at present,the hardware computing resources and capacity of vehicle BMS are limited,and the data storage capacity is limited,so it cannot apply higher precision and more complex state of charge(SOC)estimation algorithm.With the development of mobile wireless communication technology(such as 4G,5G),the data transmission delay has been greatly reduced and the transmission capacity has increased,which has met the requirements of remote on-line SOC estimation and battery pack management,therefore,it is necessary to develop a remote monitoring system for lithium battery pack to obtain real-time information such as voltage,current and temperature in the battery pack,and carry out real-time monitoring,online SOC estimation,health management,fault prediction and historical data storage,so as to make up for the deficiency of vehicle battery management system.In this article,the original vehicle battery management system is extended,and the remote monitoring system of power lithium battery pack is designed.The main research contents are as follows:(1)This article analyzes the composition and function of the vehicle battery management system,and designs the overall architecture scheme of the power lithium battery pack remote monitoring system according to the specific requirements of battery management.And the communication protocol for remote data transmission is established to support the transmission of battery data across devices and platforms.(2)In this paper,the hardware circuit for the controller is designed,and the prototype is manufactured.The software code of the vehicle controller is finished under the integrated development environment,CAN communication data link layer protocol and the migration of basing on SAE J1939 vehicle application layer protocol are completed,and the CAN communication protocol of the vehicle controller is established,it is finally realized CAN communication between the vehicle controller and the vehicle battery management system and the mobile network communication(4G communication)of the cloud servers,so as to execute two-way transmission of battery pack data and control instructions.(3)In this paper,a cloud UDP server was built and a data forwarding and storage application was developed,which realized the functions of data transfer,basic computing,battery pack working status analysis,cloud database storage,etc.,on the lithium battery remote monitoring system.Further,the database is created,and the data table structure is designed,which will be used for remote monitoring system battery data storage and monitoring center platform background service system.(4)This paper develops a computer monitoring center platform,which is useroriented and realizes the real-time receiving and analyzing of BMS battery data,as well as user management,battery management,real-time battery status information display,historical data query,chart statistical analysis and fault record processing.(5)In this paper,the remote estimation of the state of charge of the battery pack is realized based on UKF filtering technology.And through experimental verification,the conclusion is drawn that the lithium battery remote monitoring system designed in this paper has met the design requirements,the operation is basically stable,and reach the requirements of engineering application.. |
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