The sensitivity of the impedance characteristics of a laminar flow-based fuel cell (LFFC) to the changes of the voltage, current and fuel concentration is analyzed using the electrochemical impedance spectroscopy (EIS) method. The impedance of the cell measured at different fuel concentrations and voltages is modeled using equivalent circuits. A t-test is performed on the values of the elements of the equivalent circuits estimated in successive voltages and fuel concentrations. As a result, intervals for the voltage, current and fuel concentration are identified in which the changes in the impedance characteristics of the cell cannot be distinguished statistically. These intervals, referred to as indifference intervals, show that the impedance characteristics of the cell is most sensitive to the changes in the voltage and current in the moderate frequency domains and least sensitive to the changes in the fuel concentration in the low frequency domains.
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