Research On Internal Resistance Detection Of Lithium-ion Power Battery

In this thesis,the basic principle of AC impedance is adopted and designed a measurement system that can measure the dynamic internal resistance of lithium-ion battery in real-time and with high accuracy.The main research contents are as follows:The AC injection method is adopted as the main method of the test system,and proposed the overall scheme of the lithium ion battery internal resistance test system according to the method adopted.The hardware circuit of the lithium-ion battery internal resistance test system includes the signal generation section,the blocking circuit,the amplification circuit,the NI data acquisition board,the DAQ data acquisition platform,and the computer.The software design of the lithium ion battery internal resistance measurement system has completed,and the design of parts including digital filtering,orthogonal lock amplification,real-time signal processing,signal extraction module and internal resistance calculation using Labview software has completed.This design avoids the noise generated by the traditional lock-in amplifier and the error caused by the need to accurately measure the phase difference,greatly improving the accuracy and stability of the signal detection,and can complete the phase-locking function quickly.NI data acquisition card can improve the accuracy and stability of signal detection.The software can also expand the functionality according to specific needs.