Design of a fast measuring system for electrochemical impedance spectroscopy of lithium-ion battery

Electrochemical impedance spectroscopy(EIS) has many advantages such as fast, non-destructive, intuitive, and is widely used in its status and safety assessment of lithium-ion batteries. The primary prerequisite for applying impedance spectroscopy to evaluate battery status is to effectively measure the impedance spectra of lithium-ion batteries. This paper develops a set of lithium-ion battery impedance characteristics tester based on the fast Fourier transform (FFT) method. The actual test results show that the relative error of amplitude measurement is 1.5% compared with the equivalent circuit of known parameters, which proves its effectiveness. Taking a commercial electrochemical workstation as a benchmark, the average error of the modulus and phase angle of this device is 1.44% and 4.09%. In the same range of frequency, this device makes its time shorten from 5min to 52s approximately, and the cost is reduced to about 20%. The results of five consecutive measurements show that the device has good repeatability. The impedance spectroscopy measurement results of a variety of batteries with different capacities (800mAh similar to 100Ah) show that the device(EIS-1000) has a wide range of applications. EIS-1000 has faster measurement speed and lower cost, and provides an engineering application method for impedance spectrum measurement with a wide battery capacity range.