Breakthrough EV battery testing improves stability and performance

South Korean Advanced Institute of Science and Technology has developed technology for the precise diagnosis of electric vehicle batteries using small currents that can improve the stability and performance of high-capacity batteries.

October 18, 2024 Ev Foley

Image: Zaptec, Unsplash

Researchers from the Korea Advanced Institute of Science and Technology (KAIST) School of Electrical Engineering have developed electrochemical impedance spectroscopy (EIS) technology that can improve the stability and performance of high-capacity batteries in electric vehicles (EV).

The technology can precisely diagnose and monitor the state of EV batteries using small amounts of currents to measure the resistance to current flow within the battery and assess battery performance and condition.

Flow chart for diagnosis and prevention of unexpected combustion via the use of the electrochemical impedance spectroscopy (EIS) for the batteries for electric vehicles.
*Image: Korea Advanced Institute of Science and Technology*

Traditional EIS equipment is difficult to install, operate, and maintain due to cost and complexity, and can cause significant electrical stress, increasing the risk of battery failure or fire and making it difficult to use in practice.

KAIST’s EIS system can precisely measure battery impedance with low current disturbances (10mA), minimising thermal effects and safety issues during the measurement process.

In addition, the system minimises bulky and costly components, making it easy to integrate into vehicles.

The system was proven effective in identifying the electrochemical properties of batteries under various operating conditions, including different temperatures and SOC levels.

Impedance measurement results of large-capacity batteries for electric vehicles. ZEW (commercial EW; MP10, Wonatech) versus ZMEAS (proposed system).
*Image: Korea Advanced Institute of Science and Technology*

KAIST Professor Kyeongha Kwon said the system can be easily integrated into the battery management system (BMS) of electric vehicles and has demonstrated high measurement accuracy.

“It can contribute to battery diagnosis and performance improvements not only for electric vehicles but also for energy storage systems (ESS),” Kwon said.

Findings have been published in the United States-headquarted Institute of Electrical Engineers (IEEE) Transactions on Industrial Electronics journal, titled Small-Perturbation Electrochemical Impedance Spectroscopy System With High Accuracy for High-Capacity Batteries in Electric Vehicles.

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