Battery Impedance Measurement Using Pseudo Random Binary Sequences

Battery impedance is one of the most important parameters to reflect performance and health for electric vehicles and other applications, and is affected by many factors, such as temperature, battery type and aging. Based on the characteristics of pseudo random binary signals, this research presents the design, implementation and verification of methods to determine the battery impedance by using PRBSs under various conditions of temperature and age. The impact of injected current amplitude is also investigated. Results from simulation studies and measurements on a custom experimental test facility show the potential for using pseudo random binary sequences for real-time nonlinear battery system identification and show that it can provide an attractive alternative to more traditional online measurement techniques which can incur protracted measurement intervals.