Electrochemical Impedance Spectroscopy Measurement of Lithium Battery Based on Lock-in amplifier

Electrochemical impedance spectroscopy (EIS) is a useful technique in research on lithium battery. EIS is often measured by electrochemical workstations whose price is extremely high. This paper proposed a new method for measuring EIS of lithium battery, which was based on lock-in amplifier and some auxiliary circuits. The lock-in amplifier can achieve measuring ultra-low frequency small signal and the auxiliary circuits can complete the expansion of the output current and avoid the influence of the output impedance of lock-in amplifier. This method can measure EIS of lithium batteries accurately while avoid using expensive equipment such as electrochemical workstation.