Embedded spectroscopy: Potentialities and constraints for onboard battery diagnostics

This paper introduces an on-board, low-cost Electrochemical Impedance Spectroscopy technique for battery diagnostics, utilizing numerical simulations and experimental results. EIS, commonly used in laboratories to assess charge transfer and diffusion in electrochemical cells, is ideal for monitoring battery performance, state of charge, and health. However, traditional EIS equipment is too large and expensive for automotive use. The proposed system offers a compact, cost-effective solution for electric vehicles. We discuss the challenges and trade-offs for accurate on-board measurements, based on simulations. Prototype results are then compared with laboratory EIS measurements on 260 Ah Li-NMC EV pouch cells, demonstrating that embedded spectroscopy achieves precise results, even for high-capacity, low-impedance cells. The study highlights the potential of this technique as a reliable and effective method for battery diagnostics in automotive applications.