Research On Battery Management System Based On CCS Test Cabinet

Under the increasingly severe energy and environmental issues,the development of new energy vehicles has received widespread attention from countries around the world.The Battery Management System(BMS),as the core component of new energy vehicles,is mainly used to control the charging and discharging of electric vehicle batteries,and to achieve functions such as battery SOC(State of Charge)state estimation.This enables battery status monitoring,battery status analysis,battery safety protection,energy control management,and battery information management,thereby improving battery range and extending service life The goal is to reduce operating costs and ensure the safety and reliability of power battery pack applications.SOC is influenced by many factors,and traditional estimation methods have significant errors,which cannot accurately reflect the SOC state of the battery and have certain limitations.Therefore,this thesis focuses on the SOC estimation and functional module testing of the battery management system.Analyze the implementation principles of each functional module of the battery management system,and conduct research on the balance principle and its strategy focus.This thesis mainly introduces the principles of thermal management,high-voltage safety management,and charge discharge management in battery management systems.In response to the reasons for inconsistent battery states,it analyzes the topology differences between active and passive equalization strategies in BMS equalization methods,and proposes several improvement suggestions for the optimization of passive equalization circuits.Analyze the working principle and chemical characteristics of lithium-ion batteries,establish an equivalent circuit model for the battery,and identify parameters to achieve SOC estimation.By comparing the differences between several different lithium-ion battery models,it was determined to use a second-order Thevenin equivalent circuit model.Based on experimental data under HPPC operating conditions of the battery,parameter identification was completed using the least squares method.A battery equivalent model was built in Matlab,and the maximum error between the model terminal voltage value and the true value was 54.84mv;Based on the extended Kalman filtering algorithm,using experimental data from the UDDS operating conditions as model input and performing SOC estimation,the maximum error percentage between the predicted value of the model and the actual SOC value is 2.26%.Based on the CCS(Common Core System)testing equipment,complete the main functional module testing of the battery management system and analyze the results.Build a testing environment with a semi distributed architecture of one master and two slaves(one master controller mounts two slave controllers),and introduce the testing hardware requirements;Analyze the functional testing methods and principles,and conduct functional tests on the BMS’s withstand voltage insulation,high-voltage interlocking,voltage and temperature acquisition,and equalization modules.The test results comply with industry standards.