Use of integrative ADC for Electrochemical Impedance Spectroscopy of supercapacitor module under high interference conditions

This paper demonstrates the use of integrative analog-to-digital converter (IADC) based data acquisition for conducting Electrochemical Impedance Spectroscopy (EIS) procedure in order to obtain the frequency response of high voltage/current supercapacitor (SC) module under high interference conditions. Herein proposed approach presents the method to suppress the influence of voltage and current harmonics on measured data, thus ensuring insignificant errors in obtained results. Dedicated laboratory equipment for acquiring frequency response is usually only capable of testing low voltage/current SC cells. However, it is essential to be able to conduct EIS on high voltage/current SC with voltage/current levels, which are expected during exploitation. It is shown that by using the IADC together with the herein proposed data fitting method, noise is suppressed by factor of 44.2 dB compared to the sampling ADC, over the analyzed frequency range between 10 kHz and 20 kHz. In addition, it was shown that in case of herein treated SC cells the expanded uncertainty for magnitude and phase are less than 0.21 m Omega and 0.75 degrees, respectively, which are at the level of declared reference instrument errors. Furthermore, in case of SC module, obtained results for expanded magnitude and phase uncertainty are less than 6 m Omega and 0.022 degrees, respectively. It is concluded that herein proposed method offers the measurement capability at the level of used reference instrument for considered frequency range.