Design of lithium-ion battery impedance on-line measuring device
The AC impedance of a lithium-ion battery can provide internal information of the battery and is a power-ful tool for online monitoring of battery state.The design of an impedance online measurement device is the key to implementing impedance-based online estimation of battery state and fault warning technology.This study designed an online measurement device for AC impedance of lithium-ion batteries based on an embedded microcontroller.It uses an all-phase fast Fourier transform algorithm to convert time-domain data to the frequency domain,and per-forms interpolation on the conversion results,achieving online measurement of AC impedance in the frequency range of 0.01 Hz to 10 kHz.This effectively solves the problems of spectrum leakage,fence effect,and inaccurate phase calculation caused by the traditional fast Fourier transform algorithm used in current impedance online meas-urement devices.By performing static and dynamic impedance measurements on batteries with different capacities and positive electrode materials,the reliability and speed of the device were verified.The sharp change in dynamic impedance at the end of discharge was found to have certain indicative ability for battery state.This design can be easily integrated into a battery management system and has certain application value in lithium-ion battery state esti-mation and fault warning.
on-line measurement of impedancefault warningall-phase fast Fourier transformspectrum leak-agethe fence effect
万方数据
维普
