Electrochemical impedance spectroscopy enhances battery monitoring

Electrochemical impedance spectroscopy (EIS) is being utilized to monitor various aspects of battery cells through non-invasive electrical signals. This technique allows for the tracking of battery temperature, state of charge, performance degradation, and thermal anomalies.

In lithium-ion battery monitoring, EIS can detect impending thermal runaway early enough to meet the two-hour window required by the Chinese standard GB 38031-2025 before a fire or explosion occurs. The technology is also beneficial for stationary energy storage systems, as it can verify a cell's ability to deliver charge and current by measuring lithium diffusion and impedance, which cannot be determined by DC voltage alone.

Practical implementation involves passing electrical signals of different frequencies through battery cells. Specific components, such as the BQ79826Z-Q1 battery monitor and the BQ79881-Q1 battery junction box pack monitor, feature integrated EIS engines to facilitate these measurements.