The internal resistance of lithium-ion cells is an important measurement to make because the cell’s internal resistance can determine the suitability of the cell for a particular application. It can be used as a quality gate in manufacturing, as well as determine the aging or wear out of the cell.
Internal resistance can be measured as ac internal resistance (ACIR) or dc internal resistance (DCIR). Internal resistance also may be extracted from measurement of the cell’s impedance spectrum as captured by electrochemical impedance spectroscopy (EIS) instrumentation.