Online spectroscopic diagnostics implemented in an efficient battery management system

Electrochemical energy storage is critical for a range of applications spanning electrified transportation and grid energy storage, and there is a need to further improve both the active management and diagnostic capability of current battery management systems (BMS). This work presents an efficient power converter (based on the switched-inductor ladder topology), instrumentation, and an embedded control platform that can provide both active balancing and real-time diagnostic capability through electrochemical impedance spectroscopy (EIS). Cell-level diagnostics allow for non-invasive measurement of physical electrochemical battery properties that can be used to assess state of charge (SOC) and state of health (SOH). A single stage of the converter was implemented on a printed circuit board, and testing on Panasonic 18650 Li-ion battery cells was performed. Experimentation results showed efficient cell balancing, and validation against the state of the art confirmed accurate impedance measurement.