Research On Key Technologies Of Electric Vehicle Battery Management System

In recent years,due to the increasingly scarce fossil energy and environmental pollution problems,electric vehicles have been vigorously developed.The power source of an electric vehicle is a battery pack composed of a large-scale single battery in series and parallel,which is related to the performance and safety of the entire vehicle.Different single batteries have certain differences.To improve the energy efficiency of the battery pack and the safety of the entire vehicle,the battery pack must be managed.Therefore,the battery management system is particularly important.The battery management system(Battery Management System,BMS)has functions such as state estimation,balance management and thermal management,which can improve the capacity utilization and life of the battery pack.This paper takes the State of Charge(SOC)estimation in the battery management system and the balance of battery pack inconsistency as the research object,and conducts the research on the SOC estimation method and the balance strategy.The main contents of this paper are:1.The characteristics and models of lithium-ion batteries are studied,and the reasons for the inconsistency of single batteries are analyzed.Taking a ternary lithium battery as an example,a battery test system is used to perform a charge and discharge test on the lithium battery,and the current,voltage and other data obtained are recorded.Through the analysis of the characteristic parameters of the battery and the comparison of various equilibrium variables,the working voltage is selected as the criterion of the equilibrium control strategy.2.Analyze the different methods of SOC estimation,choose the neural network method to realize the SOC estimation,and propose a lithium battery SOC estimation method based on the PSO-RBF neural network.Use the data obtained from the experiment to learn and train the neural network in MATLAB.The prediction result is compared with the traditional RBF neural network prediction result,which verifies the efficiency and accuracy of the proposed method.3.Analyze different equalization methods,study the topological structure of the existing active and passive equalization circuits,and through comparative analysis,propose a layered equalization structure that can achieve simultaneous equalization within and between power battery packs,and build in MATLAB/Simulink The balanced circuit model compares the simulation results of the layered balanced circuit with the simulation results of the non-layered balanced circuit,verifying that the proposed layered balanced topology can solve the inconsistency between batteries more quickly.4.Using STM32 as the control chip,according to the hierarchical and balanced topology,the equalization circuit,sampling circuit and main control circuit are designed,and the equalization experiments under the three states of standing,charging and discharging are carried out.The final experimental results verify the proposed The effectiveness of the hierarchical equalization circuit.Figure[47]table[12]reference[81]...