Research On SOC Measurement Uncertainty Evaluation Method Of Power Battery

Battery management system is one of the core components of electric vehicles.Battery Management System’s performance is directly related to the electric cars’ safe and service life.With the popularity of electric vehicles,the detection of the Battery Management System becomes the current problem needed to be solved by the electric vehicle industry.The estimation accuracy of the Power Battery ’s state of charge(SOC)is a key of Battery Management System’s detection content.In this paper,based on SOC test of battery management system,proposed a complete evaluation method SOC measuring uncertainty of power battery.In this paper,the working principle of lithium battery and the characteristics of charge discharge data are analyzed.A data processing method for charge and discharge of Li ion battery based on Gauss process is proposed.Compared with Least squares fitting and Gauss fitting,the charging and discharging curves have higher prediction accuracy.The author refered the SOC test items of standard QC/T897-2011 "Technical specification of Battery Management System for electric vehicals".Formulated the uncertainty evaluation scheme of battery measurement,according to the characteristics of power measurement,establishment of battery charge discharge model based on Gaussian process.the analysis of uncertain factors affecting measurement model,determine the probability density function of the amount of input power measurement model,the evaluation of different charge and discharge mode measurement uncertainty using Monte Carlo method.The influence of battery aging on discharge capacity is analyzed.A method for estimating battery health(SOH)using gaussian process regression algorithm is proposed,and used different kernel functions to estimate SOH.According to the estimation method of SOH,the uncertainty of capacity estimation is put forward,the available capacity is tested,and the uncertainty of available capacity is evaluated.The SOC testing system based on virtual instrument measurement technology is designed,and the hardware test platform is built.The software platform is designed by using Labwindows/CVI of NI company.The test system is used to complete the estimation precision in the experiment of detecting the battery management system SOC,SOC test system is built after the completion of the battery charge and discharge sampling data,and test SOH under different working conditions,according to the experimental data evaluation SOC measurement uncertainty.