Real-time impedance monitoring of Li-ion batteries under dynamic operating conditions using the discrete Fourier transform eigenvector approach

<h2>Summary</h2> The impedance of Li-ion batteries has been recognized as a vital parameter in ensuring consistent performance of the battery management system. Thus, real-time monitoring of the impedance and its inclusion in battery management algorithms can have significant incremental impact on the safety, efficiency, and lifetime of the battery and the application. However, the prevailing impedance monitoring methods struggle to operate in real time and under dynamic operating conditions, limiting their practical use in real applications. This article presents a new impedance monitoring approach that delivers valid and reliable real-time results under typical battery load profiles. The proposed approach has been shown to perform under various charge, temperature, and dynamic current conditions, such as with one corresponding to a driving profile of an electric vehicle. Besides the robust performance, the approach is also fast, accurate, and easy to implement, making it a potentially cost-effective solution for real-world applications.