Study On Battery Management System Of MH/NI Batteries And Estimation Of SOC

This thesis is worked on the SOC of battery management system, The prediction of discharge capacity of MH/NI battery is a main part of battery management system. The exact and reliable soc of estimation for battery is necessary for the battery management system in HEV, it is the key of practical of the HEV. since the actual SOC of MH/NI battery is influenced by many factors, such as temperature, cycle of discharge and aging of battery, it is difficult to obtain ideal results by traditional methods, the application of ANN method for the SOC estimation is described. The research achievements and innovations in this paper are as follows:Having analyzed the electronic mechanism of the MH/NI batteries during charge and discharge, compared the advantages of MH/NI batteries with other kinds of batteries, the result is MH/NI batteries is the promising power battery for HEV due to its advantages such as high power lever and long life.Principle of the reaction of the MH/NI battery, the characteristics and existed problems of different kinds of SOC measuring methods are compared, such as use voltage or resistance of the batteries to get the SOC, then put forward the way of ANN to estimate SOC of the batteries in this research.We used P87C591 as the microcontroller, using the sensor to collect the data of voltages and temperature of batteries, transcend them on CAN field bus , through the CAN net constructed the whole distributed battery management system, and give the design of the relevant hardware and software.In order to estimate SOC effectively, based on the principle of the charge and discharge of the MH/NI batteries,' analyzed the traditional ways of estimating SOC, in this research paper a neural network model of MH/NI batteries on LM network was built up. The artificial neuralnetwork(ANN) method, which can be used to approach non-linear function with many input/output parameters, is originally used to estimate the discharge capacity of MH/NI batteries when changing the discharge current and Voltage .The satisfactory result has been obtained from comparison of simulation results.