Study On SOC Estimation Of Lithium-ion Battery Module Based On Thevenin Equivalent Circuit Model

In recent years, the quantity of global vehicles increases sharply, andthe demand for energy is larger and larger. In addition, vehicle industrybrings serious pollution.Therefore people begin to pay attention to the newenergy vehicle, especially electric vehicles. However, there are lots oftechnology restrictions such as the performance of storage battery.Prolonging the battery life and improve battery energy efficiency as well asreliability become an important issue of the industrialization of electricvehicles. Thus, it makes great significance to study battery managementtechnology.Battery model can be used in the simulation of vehicle performance,battery and battery management system (BMS). In addition, battery modelcan help to simulate and validate the stratage of battery management.Based on the research of battery model home and abroad, this paper tooklots of battery performance test at, and introduced Lithium-ion batterymodel with the Parameter Estimation tool in Matlab/Simulink.Research of SOC estimation has been very hot, but the accuracy hasnot been satisfying. This paper will choose Coulomb counting as the mainmethod to calculate SOC, and will choose load-voltage method anditerative correction algorithm to achieve SOC correnction.Firstly in oreder to help to understand the battery perforamce, thispaper introduces the electrochemical properties of the lithium-ion battery,followed by a series of lithium-ion battery test and some analysis results ofthe test.And then, this paper proposed the hardware and software design ofthe accuquisition system.Then, this paper completes the modeling of the battery module based on the battery test result and the ParameterEstiamtion tool in Matlab/Simulink.Finally, this paper proposed themethod to calculate and calibrate SOC.