Small-Perturbation Electrochemical Impedance Spectroscopy System with High Accuracy for High-Capacity Batteries in Electric Vehicles

A KAIST research team led by Prof. Kyeongha Kwon and Sang-Gug Lee has developed an electrochemical impedance spectroscopy (EIS) system for precise diagnosis of high-capacity batteries using minimal current. This innovation enhances safety and performance metrics in electric vehicle (EV) battery systems.

The EIS methodology quantifies battery impedance responses to small electrical signals across frequency ranges, providing critical data on internal battery parameters including state of charge, state of health, and degradation indicators. The technique facilitates detection of variations in temperature-dependent properties, electrochemical reactions, and structural integrity—parameters essential for accurate prediction of battery performance and operational lifespan.

Conventional EIS instrumentation is characterized by substantial size, high cost, and significant current requirements, potentially introducing thermal stress and safety concerns. The KAIST-developed system operates at substantially reduced current levels (≤10 mA), thereby minimizing thermal effects and mitigating safety risks during measurement procedures.

The system’s compact architecture eliminates bulky components and facilitates vehicle integration. Validation studies across diverse operational conditions demonstrate robust accuracy in battery health monitoring across temperature gradients and charge states. This approach provides a viable solution for advanced battery management systems in EV applications.

Prof. Kwon noted, “This system demonstrates compatibility with existing battery management systems (BMS) in electric vehicles and exhibits high measurement precision while significantly reducing cost and complexity compared to conventional high-current EIS methodologies. Applications extend beyond electric vehicles to energy storage systems (ESS).”

This research was published in IEEE Transactions on Industrial Electronics (top 2% in field; Impact Factor 7.5) on September 5th, 2024. (Paper Title: Small-Perturbation Electrochemical Impedance Spectroscopy System With High Accuracy for High-Capacity Batteries in Electric Vehicles, Link: https://ieeexplore.ieee.org/document/10666864)