The importance of using four-terminal sensing for EIS measurements on low-impedance systems

In this application note, electrochemical impedance spectroscopy (EIS) is used to test a commercial battery connected in two different ways. In the first EIS measurement, the battery is connected in a two-terminal sensing configuration. In the second EIS measurement, the battery is connected in a four-terminal sensing (Kelvin sensing) configuration. The difference in how the leads are connected results in different measured impedance values for the battery.