DIFFERENTIAL ELECTRICAL IMPEDANCE SPECTROSCOPY

A device having a structure to measure a battery parameter of a battery of a set of multiple batteries can be implemented in a variety of applications. The device can be structured to measure alternating current (AC) electrical impedance of a battery cell by processing a difference between the battery cell and another battery cell. The battery cell being measured is subjected to AC excitation while the other one is not, where the two battery cells share a common load current. This differencing method can reduce the measurement's sensitivity to noisy battery load current, which is common to both battery cells. This differencing method also can remove or substantially reduce a large direct current (DC) offset, that is, the battery potential itself under which the AC signal measurement is burdened.