KAIST team’s new EIS technology enhances EV battery management

News, 17th October 2024

The Korean research team has made a breakthrough in the field of electric vehicle (EV) battery diagnostics, developing a technology that would lead to long-term stability and efficiency of these batteries. The Korea Advanced Institute of Science and Technology (KAIST) announced that Professors Lee Sang-kook and Kwon Kyung-ha from the Department of Electrical Engineering have developed electrochemical impedance spectroscopy (EIS) technology. This invention can determine and monitor the state of batteries with precision using only a small amount of current.

The research team of KAIST, which includes Ph.D. candidate Lee Young-nam, has developed an EIS system that can be integrated into battery management systems (BMS) for electric vehicles. This system has ability to precisely measuring battery impedance with low current disturbances of just 10mA, significantly reducing thermal effects and safety issues during measurement. This development is expected to enhance the long-term stability and efficiency of EV batteries, acknowledging a critical need in the growing electric vehicle market.

The technology of EIS is a powerful tool that evaluates battery efficiency and losses, by measuring the magnitude and changes in battery hindrance. It can also recognise thermal characteristics, chemical and physical changes, lifespan predictions, and the causes of failures in batteries. However, existing EIS equipment is complex and costly, making installation, working, and, preservation challenging. Additionally, the disturbances of high current required by traditional EIS systems presents notable electrical stress on batteries, increasing the risk of fire or failure.

The development of new low-current EIS system by the KAIST team overcomes these challenges. By lowering down bulky and expensive components, the system is easy to integrate into vehicles and has been proven effective in identifying the electrochemical characteristics of batteries under various operating conditions, such as different temperatures and state of charge (SOC) levels.

This system can be easily integrated into Battery Management Systems (BMS) for electric vehicles, demonstrating high measurement precision while significantly reducing costs and complexity compared to traditional high-current EIS methods,” says Prof. Kwon. “It can contribute not only to electric vehicles but also to the diagnosis and performance enhancement of Energy Storage Systems (ESS) batteries.”

The outcome of this study were published in the international academic journal IEEE Transactions on Industrial Electronics on Sept. 5, culminating the scientific rigor and peer-reviewed validation of the research.