In Situ Characterization of Lithium-Ion Battery Dynamic Impedance Spectrum for Real-World Driving Applications

Dynamic electrochemical impedance spectroscopy (DEIS) provides critical insights into the kinetic pathways of Lithium-ion batteries under dynamic operating conditions, establishing its significance in advanced onboard diagnostics. However, accurate DEIS implementation faces challenges due to voltage drifts arising from load fluctuations, state of charge (SOC) variations, and temperature changes. To address these issues, this work proposes a novel differencing framework that systematically suppresses drifting components while preserving the integrity of perturbation and response signals, enabling precise in situ frequency response analysis. Analytical criteria are established to select differencing lags and orders, effectively mitigating disturbances without compromising frequency-domain responses under dynamic driving conditions. Comprehensive experimental investigations across diverse SOC levels, driving profiles, thermal environments, and battery aging states validate the method, achieving consistently accurate and stable DEIS measurements with maximum absolute residuals below 0.6% under Kramers-Kronig validation.