Wide-frequency band measurement and analysis of electrochemical noise of Li/MnO2 primary battery

摘要

The electrochemical noise of a commercially produced Li/MnO2 primary battery was measured during discharge via a constant value resistor. Power spectral density frequency dependences were calculated for different state of charge values across the frequency band from 0.02 to 5kHz. It was shown that they possess close to linear frequency dependences. For high state of charge values, an intersection with the thermal noise spectrum was observed in a high-frequency band. The electrochemical impedance of the investigated type of battery was measured at different charge values both during discharge and following a relaxation pause. Impedance spectra obtained under load conditions were used to model the electrochemical noise spectra. It was shown that impedance parameters can be used to describe the electrochemical noise spectra in the frequency band above 500Hz at state of charge values higher than 50%. Dependencies of electrochemical noise amplitude on discharge current value were investigated at different states of charge. It was shown that power spectral density has a linear dependency on discharge current at a power of about 2 for a charged battery and 2.5 for a discharged battery.