Electrochemical impedance spectroscopy (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 ultralow power analog front end (AFE), the system discussed in this paper is designed to excite and measure 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. Read the paper for more EIS benefits.