CN0510 Electrochemical Impedance Spectroscopy (EIS)

ADI's EIS is a safe perturbation technique used to examine processes occurring inside electrochemical systems. The system measures the impedance of a battery cell over a range of frequencies. The data can determine the state of health (SOH) and state of charge (SOC) of a battery. Using an ultra-low power analog front end (AFE), this system is designed to excite and measure the current, voltage, or impedance response of a battery.

Aging leads to performance degradation and irreversible changes in battery chemistry. Impedance increases linearly with the decline in capacity. Monitoring the increase in impedance of a battery using EIS can determine the SOH and whether the battery needs replacing, reducing both system downtime and maintenance costs.

Batteries require a current excitation, not voltage, and the impedance values are small, in the milliohm range. This system includes the necessary circuitry to inject a current into the battery and allows for calibration and sensing of the small impedances found in batteries.