Nonlinear dynamics of fuel cells: a review

Abstract

Over the last decade, nonlinear phenomena in low-temperature fuel cells as well as high-temperature fuel cells have been reported in the open literature. Experimental and theoretical studies found multiple steady states as well as periodic oscillations. The present article gives an overview of publications on this subject. Instead of sorting the analyses according to the types of fuel cells, this work used the source of the nonlinearity for classifi cation. In the fi rst part of the contribution, a very simple prototype fuel cell model is introduced. The model helps to give a qualitative explanation of the majority of nonlinear effects reported in literature. It is further used to identify potential sources of nonlinear behavior in reaction kinetics, membrane properties, and mass transport mechanisms. A classifi cation scheme that is based on types of negative differential resistance (NDR) and was originally introduced by K. Krischer in Modern Aspects of Electrochemistry (Vol. 32, p. 1, Plenum Press, 1999) for electrochemical systems is applied to fuel cells. The second part of the work classifi es the fi ndings from literature according to their NDR type. Instabilities resulting not from electrochemistry but from other mechanisms such as water formation and reactant starvation are also discussed.

Voltage Inversion Caused by Self-organized Oscillations in a Direct Formic Acid Fuel Cell

“…Beyond half-cell, laboratory experiments, kinetic instabilities have been also found in polymer electrolyte membrane fuel cells (PEMFC) fed with CO contaminated H 2 [3] [4] [5] and, more recently, methanol [6] and formic acid [7]. Under oscillatory regime, most systems are expected to result in higher efficiency [2] [3] [4] [8] [9]. Motivated by the recent reports of oscillatory kinetics in fuel cell fed directly with carbon-containing fuels [6] [7], we have investigated the occurrence of voltage oscillations in a Direct Formic Acid Fuel Cell (DFAFC).…”

A thermally self-sustained micro-power plant with integrated micro-solid oxide fuel cells, micro-reformer and functional micro-fluidic carrier

“…The I-V curves were measured in the potentiostatic mode only. Hanke-Rauschenbach et al [41] call such behavior a N-shaped negative differential resistance (N-NDR) type current-voltage curve. It is highly improbable that fuel depletion caused this behavior as more than 10 vol.% of hydrogen was generated at the reformer [42].…”

Nonlinear Behavior of Nickel Dissolution in Sulfuric Acid in a Cathode-Anode Cell Configuration: Effect of Cathode Area

“…However, most electrochemical applications utilize cells in two-electrode configurations with a cathode and an anode. Oscillations have been observed in fuel cells [5][6][7] and batteries. [8][9][10] For example, hydrogen oxidation in the presence of inhibiting CO, which exhibits oscillations in three-electrode configuration, can also exhibit oscillations in fuel cell configurations.…”