Research And Design Of Battery Management System Based On Cloud Platform

At present,fuel vehicles are banned by an increasing number of countries,and the development Electric Vehicles has become a consensus of major countries.As one of the key technologies of electric vehicles,battery management system(BMS)plays an overwhelmingly important role in improving the service life of battery system and ensuring driving safety.In accordance with the functional requirements and practical application requirements of the BMS,a Battery Management System for lithium iron phosphate batteries is designed in this paper.The main work as follows:(1)The Thevenin equivalent circuit model is established on the base of analysing the working principle and model of lithium iron phosphate battery.And the battery equivalent circuit model is identified by Matlab/Simscape tool base on the experimental data of battery charge and discharge.In addition,an accurate model is provided for the estimate of subsequent batteries’ SOC.In order to cope with the issue of low estimation accuracy of on-line battery SOC,the Thevenin equivalent circuit model and the Extended Kalman filter method are used to estimate SOC.Compared with the discharge test method,the error rate of this estimation algorithm is less than 5%.(2)A distributed topology structure is adopted for the hardware design.In addition,the circuit,Battery Control Unit(BCU),Battery Measurement Unit(BMU)and the communication module,etc are designed.At the same time,a modular programming idea is utilized for the software design to complete the design of the battery management system based on the cloud platform.(3)A Backstage Management System of Web pages based on China Mobile’s OneNET cloud platform are also designed in this system.The data of BMS through 4G DTU module can be uploaded and analyzed.Then,the status of battery system can be displayed in real time.Furthermore,an APP based on the backstage management system is designed.APP can access the important battery data by calling the data of backstage management system,and users can easily acquaint the real-time status of the battery system.Finally,a test platform is established to test the function of the BMS includes the functions of data acquisition and the SOC estimation based on the cloud platform and mobile APP.The results illustrate that the function of each module met the requirements of relevant standards.