Practical broadband measurement of battery EIS

In this paper, a low-complexity practical system for electrochemical impedance spectroscopy of batteries is presented. The system is based on a voltage-controlled current generator and on the acquisition of current and voltage signals from the battery under test. Arbitrary current waveforms can be generated, thus the system is flexible and reconfigurable. In particular, a broadband multisine excitation signal is used, enabling faster measurements with respect to the conventional stepped-sine approach. The multisine method and the stepped-sine method are compared using the proposed system. Furthermore, the proposed system is characterized by repeated measurements on a 18650 lithium-ion battery and by comparison with a commercial benchtop instrument. Results show that the system is able to accurately and repeatably measure the impedance of a battery in a wide frequency range from 0.05 Hz to 1 kHz. Furthermore, it provides results that are consistent with the commercial instrument.