Application Of Lithium-ion Battery SOC Estimation For Electric Vehicle And Correction Research On Data Acquisition Problem

The expansion of the scale of the city and the emphasis of environmental issues have led to the rapid development of new energy automotive industry,including electric vehicles can be said that the mainstream of new energy vehicles.Battery is an essential part of electric vehicles.Battery cost,life,charge and discharge efficiency and other issues restrict the development of electric vehicles.So it is conducive to saving the cost of the electric vehicles battery to promote the development of electric vehicles to use of batteries better and give full play to the performance of the battery.The Battery management system measures and monitors battery parameters in order to use the battery better.The state of charge of the battery is one of the indispensable parameters.It can provide a reference for the battery charge and discharge and driving of electric vehicles to estimate SOC quickly and accurately.In this way,it is more rational to use batteries for us.The life of the battery will be extended.After studying the SOC estimation method that have been existed,method of combining the open circuit voltage method with the Ah integral method is selected to estimate the state of charge of the battery.The open-circuit voltage of the battery is obtained by using the least squares method with forgetting factor.Next,the SOC is estimated by the relationship between the open circuit voltage and the state of charge.Then,another state of charge is obtained by using the Ah integration method.Finally,Combined two SOC that obtained by the two methods to obtain the current time the state of charge of battery.The realization of the algorithm needs to select the appropriate hardware.This paper selects the dual-core chip F28M35H52 C that integrated ARM and DSP as the hardware processor.Data operations and transmission are completed in two subsystems.This paper completes the design of the hardware and software system,estimates the state of charge on the hardware platform,and outputs the estimation result and saves it.When the state of charge is estimated based on the hardware,the practical application of the algorithm is not completed.In the actual application process,there will be a variety of situations to cause the error of the SOC estimation result.Mainly the following cases may be occur: the input voltage data and the input current data are not synchronized and the sampling frequency changes.In order to solve this problems in the early data acquisition process.Study the impact of SOC estimation results by these problems caused and propose solutions.