Reconstruction of Electric Currents in a Fuel Cell by Magnetic Field Measurements

In this paper the tomographic problem arising in the diagnostics of a fuel cell is discussed. This is concerned with how well the electric current density j(r) be reconstructed by measuring its external magnetic field. We show that (i) exploiting the fact that the current density has to comply with Maxwell’s equations it can, in fact, be reconstructed at least up to a certain resolution, (ii) the functional connection between the resolution of the current density and the relative precision of the measurement devices can be obtained, and (iii) a procedure can be applied to determine the optimum measuring positions, essentially decreasing the number of measuring points and thus the time scale of measurable dynamical perturbations—without a loss of fine resolution. We present explicit results for (i)–(iii) by applying our formulas to a realistic case of an experimental direct methanol fuel cell.

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Critique and Improvement of a One-Dimensional Semianalytical Model of a Direct Methanol Fuel Cell

Journal of Fuel Cell Science and Technology ◽

10.1115/1.4006842 ◽

2012 ◽

Vol 9 (5) ◽

Cited By ~ 2

Author(s):

C. C. Kuo ◽

W. E. Lear ◽

J. H. Fletcher ◽

O. D. Crisalle

Keyword(s):

Fuel Cell ◽

Polarization Curve ◽

Current Density ◽

Direct Methanol Fuel Cell ◽

Membrane Electrode Assembly ◽

Membrane Electrode ◽

One Dimensional ◽

Implicit Equation ◽

Direct Methanol ◽

Methanol Fuel Cell

A constructive critique and a suite of proposed improvements for a recent one-dimensional semianalytical model of a direct methanol fuel cell are presented for the purpose of improving the predictive ability of the modeling approach. The model produces a polarization curve for a fuel cell system comprised of a single membrane-electrode assembly, based on a semianalytical one-dimensional solution of the steady-state methanol concentration profile across relevant layers of the membrane electrode assembly. The first improvement proposed is a more precise numerical solution method for an implicit equation that describes the overall current density, leading to better convergence properties. A second improvement is a new technique for identifying the maximum achievable current density, an important piece of information necessary to avoid divergence of the implicit-equation solver. Third, a modeling improvement is introduced through the adoption of a linear ion-conductivity model that enhances the ability to better match experimental polarization-curve data at high current densities. Fourth, a systematic method is advanced for extracting anodic and cathodic transfer-coefficient parameters from experimental data via a least-squares regression procedure, eliminating a potentially significant parameter estimation error. Finally, this study determines that the methanol concentration boundary condition imposed on the membrane side of the membrane-cathode interface plays a critical role in the model’s ability to predict the limiting current density. Furthermore, the study argues for the need to carry out additional experimental work to identify more meaningful boundary concentration values realized by the cell.

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Magnetic field aligned nanocomposite proton exchange membranes based on sulfonated poly (ether sulfone) and Fe2O3 nanoparticles for direct methanol fuel cell application

International Journal of Hydrogen Energy ◽

10.1016/j.ijhydene.2011.08.068 ◽

2011 ◽

Vol 36 (23) ◽

pp. 15323-15332 ◽

Cited By ~ 46

Author(s):

Noushin Hasanabadi ◽

Seyed Reza Ghaffarian ◽

Mohammad Mahdi Hasani-Sadrabadi

Keyword(s):

Magnetic Field ◽

Fuel Cell ◽

Direct Methanol Fuel Cell ◽

Proton Exchange Membranes ◽

Proton Exchange ◽

Fe2o3 Nanoparticles ◽

Fuel Cell Application ◽

Direct Methanol ◽

Methanol Fuel Cell ◽

Sulfonated Poly

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The Effects of Membrane Thickness on the Performance and Impedance of the Direct Methanol Fuel Cell

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/09544062jmes1980 ◽

2010 ◽

Vol 224 (10) ◽

pp. 2211-2221 ◽

Cited By ~ 2

Author(s):

S H Seo ◽

C S Lee

Keyword(s):

Fuel Cell ◽

Current Density ◽

Direct Methanol Fuel Cell ◽

Impedance Measurement ◽

Open Circuit ◽

Operating Conditions ◽

Membrane Thickness ◽

Ohmic Loss ◽

Direct Methanol ◽

Methanol Fuel Cell

The purpose of this work is to investigate the effect of membrane thickness on direct methanol fuel cell (DMFC) performance and impedance under various operating conditions including operating temperature, methanol concentration, cathode flowrate, and cathode backpressure. The experiments were conducted by using three membranes of NRE-212 (50.8 m), N-115 (127 m), and N-117 (183 m) loading Pt—Ru (4 mg/cm<sup>2</sup>) and Pt-black (4 mg/cm<sup>2</sup>) at the anode and the cathode, respectively. The DMFC performance was analysed in terms of a polarization curve expressed by measuring voltage and current density and power—current density. In order to analyse performance losses such as activation loss and ohmic loss, the real and imaginary components of impedance were measured by AC impedance measurement system at various frequencies. Also, the crossover current at the open circuit was measured by using humidified nitrogen at the cathode and power supply. It was shown that DMFC performance was improved by the reduction of resistance for proton transport at the thinner membrane under the same test conditions. The comparison of open circuit voltage shows that using of a thicker membrane results in a larger value than that of using a thin membrane due to the decrease in methanol crossover.

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