Fast-Settling Onboard Electrochemical Impedance Spectroscopy System Adopting Two-Stage Hilbert Transform

Electrochemical impedance spectroscopy (EIS) is a non-invasive method for analyzing battery states based on impedance measurements. With the widespread use of high-capacity lithium-ion batteries in the range of mΩ impedance, achieving highly accurate impedance measurements becomes crucial for precise battery examination. EIS systems frequently utilize a digital lock-in amplifier (DLIA) to achieve ultra-precision impedance readings, but it requires a long settling time. This study proposes an innovative EIS architecture with a two-stage Hilbert transform that significantly reduces the measurement time by widening the bandwidth of noise suppression low-pass filter while maintaining high accuracy. It achieves a substantial 66% reduction in the estimated settling time at the lower bound frequency of 1 Hz and a 57% reduction in the total measurement time across the frequency range of 1-to-1k Hz.