New methodology of electrochemical noise analysis and applications for commercial Li-ion batteries

Abstract

Electrochemical noise analysis (ENA) is performed on ICR 18650 commercial lithium-ion batteries. The interest of ENA relates with the possibility of in-situ diagnostics during charging or discharging of the battery. Thus, the extraction of small voltage fluctuations should take into account the time evolution of the mean signal. The non-stationary character of the phenomenon (charging and discharging battery) limits the use of traditional methods of signal filtering and attenuation, so a special methodology has been developed to calculate the noise standard deviation (STD). A good reproducibility of the results has been demonstrated, and V-shape form curves have been obtained with a minimum STD value at about 55 % of state of charge (SOC). It can be noted also that fast discharge provided with 3.3 Ω load is noisier than the slow one with 5 Ω load. Some promising results have been obtained regarding the possibility of battery state of health determination.

New approach for PEMFC diagnostics based on quantitative description of quasi-periodic oscillations

“…Namely, the number of modes K and the decomposition coefficients Ac k and As k have been found from Eq. (11). The distributions of the decomposition coefficients Ac k , As k together with its modulus are depicted in Fig.…”

Electrochemical Noise as a Diagnostic Tool for PEMFC

“…Statistical parameters of fluctuations depend on the present fuel cell's physical and chemical state and potentially have capacities, which allow implementation of FC components technical diagnostics , , , , . In other words, the analysis of FC electrical current and voltage fluctuations will allow to obtain information about the actual values of membrane resistance, electrochemical reaction rate, and states of gas‐diffusion and catalytic layers.…”

“…Fluctuations in electrochemical systems introduced by turbulent fluctuations of electrolyte (turbulent noise) have been intensively studied from the theoretical and experimental points of view in [24][25][26][27][28]. The approaches which allow estimating the technical state of electrochemical power sources are presented in [23,[29][30][31][32][33][34][35].…”

Spectral method for PEMFC operation mode monitoring based on electrical fluctuation analysis

“…However, these problems can be solved by means of the PEMFC technical state diagnostics [3][4][5][6] adopted to detect and possibly predict failures at the initial stages and to try to neutralize the e ects of failures to keep high operational characteristics. Development of corresponding methods and systems is an extremely di cult task since PEMFC operation is determined by several factors (pressure, reactant gases humidi cation, cell temperature, electrical operation mode, and others) and also considerably depends on the current technical state of membrane electrodes assembly and gas transport channels [1,[7][8][9]. All these factors have a great deal of in uence on energy conversion e ciency and operation stability.…”

“…The latest research [7][8][9][10] shows that electric uctuations re ecting physical processes occurring in electrochemical objects can be used for diagnostic purposes. Compared to other traditional electrochemical methods (polarization curve, electrochemical impedance spectroscopy, etc.…”