Design Of Lithium Battery Management System

With the rapid development of the new energy and communication industry,the energy saving and environmental protection consciousness of human increase ceaselessly.Due to its long cycle life,no environmental pollution and other unique advantages,lithium ion batteries as the energy storage battery get the favour of people quickly.Since the application of lithium ion battery is more and more extensive,people hope to achieve the remote management of distributed energy storage lithium battery pack through the use of advanced information technology,no longer restricted within the aspect of use.The lithium battery management system(BMS)is playing this kind of role.This paper grasps the lithium battery management system requirements from multiple perspectives and designs a safe,efficient and flexible lithium battery management system.The main results are as follows:(1)The design idea of the front and back office system is putted forward based on the system requirements analysis and the work of the system can be arranged reasonably.The design of the lithium battery management system is completed by using C/S and B/S mixed software architecture on the.NET platform.That is,the background system uses C/S architecture to implement communication with the GPRS data transmission units(DTU),therefore,it can guarantee the safety when the data of system is transmited.The foreground system uses B/S architecture and achieves flexible human-computer interaction.Specific design includes:the conceptual model,logical structure and physical structure of the database are designed reasonably based on the anylasis of need;the model of multi task parallel programming is used to realize the design of the communication interface of the background system,which is convenient for the data transmission between BMS and multi clients;according to the human-computer interaction requirements of the BMS,the foreground system is divided into several different functional modules,and the detailed functions and realization ways of each module are given;according to the principle of UI design,the operation interface of the system is designed to provide users with a simple,flexible and friendly interface.(2)This paper proposes the error back propagation(BP)neural network method as the SCC estimation method by summarizing the influence factors for estimating the state of charge(SOC)of lithium battery,contrasting and analysing several common estimation methods comprehensively.Meanwhile,the neural network model and its algorithm are studied in detail.On this basis,first,through the analysis of specific issues,we determine the network layers,the input and output parameters of the BP neural network;next,the training samples are pretreated to improve the performance of neural network;then,according to the empirical formula,the neural network is trained by the heuristic method and the number of hidden layer nodes is determined;finally,the discharge capacity of test samples are estimated on the MATLAB,the estimation results are satisfactory and meet the design requirements of the system.And it is proved that the BP neural network with double hidden layer has higher precision for the SOC estimation of lithium battery pack.(3)The complete experimental platform of system is constructed to test and verify the front and back office system of the BMS.The test shows that all aspects of the system are running normally,the background system can receive the data accurately and reliably,and the data can be analyzed and stored successfully;the foreground system can analyze the data effectively and provide a flexible human-computer interaction function.The test results verify that the design of system is accuracy and feasibility.