PEM Fuel Cell Stack Heat and Mass Management

Hydrodynamics of gases in the cathode of a proton exchange membrane fuel cell that is contacted to an interdigitated gas distributor are investigated using a steady-state multicomponent transport model. The model describes the two-dimensional flow patterns and the distributions of the gaseous species in the porous electrode and predicts the current density generated at the electrode and membrane interface as a function of various operating conditions and design parameters. Results from the model show that, with the forced flow-through condition created by the interdigitated gas distributor design, the diffusion layer is greatly reduced. However, even with a much thinner diffusion layer, diffusion still plays a significant role in the transport of oxygen to the reaction surface. The results also show that the average current density generated at an air cathode increases with higher gas flow-through rates, thinner electrodes, and narrower shoulder widths between the inlet and outlet channels of the interdigitated gas distributor.

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“…The temperature dependence of the diffusion coefficient is obtained from Ref. 15 [6] where the constant b is given in Ref. 15.…”

Section: Model Developmentmentioning

confidence: 99%

“…[3][4][5] Water and heat management issues associated with the membrane hydration state and its proton conductivity during operation are better understood and are being addressed. [6][7][8] However, the system is still not fully optimized in terms of performance and costs to be competitive with the principal competitor, the combustion engine.…”

mentioning

confidence: 99%

Multicomponent Transport in Porous Electrodes of Proton Exchange Membrane Fuel Cells Using the Interdigitated Gas Distributors

Nguyen

1999

J. Electrochem. Soc.

307

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“…3 Next, even though a PEM fuel cell is a very efficient system, there is still 40-50% of the energy produced dissipated as heat. 4 This thermal generation is due to the irreversibility of the cathodic reaction, ohmic resistance, and mass-transport overpotentials. The thermal distribution has a strong impact on the fuel cell performance by affect-* Electrochemical Society Student Member * * Electrorhemical Society Active Member.…”

Section: Introductionmentioning

confidence: 99%

An Along‐the‐Channel Model for Proton Exchange Membrane Fuel Cells

Nguyen

1998

J. Electrochem. Soc.

372

205

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An along-the-channel model is developed for evaluating the effects of various design and operating parameters on the performance of a proton exchange membrane (PEM) fuel cell. The model, which is based on a previous one, has been extended to include the convective water transport across the membrane by a pressure gradient, temperature distribution in the solid phase along the flow channel, and heat removal by natural convection and coflow and counterflow heat exchangers. Results from the model show that the performance of a PEM fuel cell could be improved by anode humidification and positive differential pressure between the cathode and anode to increase the back transport rate of water across the roembrane. Results also show that effective heat removal is necessary for preventing excessive temperature which could lead to local membrane dehydration. For heat removal and distribution, the counterflow heat exchanger is most effective.

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“…The PROX reaction has been extensively investigated on Pt/Al 2 O 3 catalysts [56][57][58][59][60][61]. Oh and Sinketvitch [59] observed a maximum in CO conversion with temperature on 0.5% Pt/Al 2 O 3 at ca.…”

Section: Preferential Oxidation Of Co (Prox)mentioning

confidence: 99%

CO-free fuel processing for fuel cell applications

2003

Fuel and Energy Abstracts

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In view of the stringent CO intolerance of the state-of-the-art proton exchange membrane (PEM) fuel cells, it is desirable to explore CO-free fuel processing alternatives. In recent years, step-wise reforming of hydrocarbons has been proposed for production of CO-free hydrogen for fuel cell applications. The decomposition of hydrocarbons (first step of the step-wise reforming process) has been extensively investigated. Both steam and air have been employed for catalyst regeneration in the second step of the process. Since, PEM is poisoned by very low (ppm) levels of CO, it is essential to eliminate even trace amounts of CO from the reformate stream. Preferential oxidation of CO (PROX) is considered to be a promising method for trace CO clean up. Related studies along with a discussion of catalytic ammonia decomposition (for applications in alkaline fuel cells) will be included in this review.

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PEM Fuel Cell Stack Heat and Mass Management

Cited by 4 publications

References 5 publications

Multicomponent Transport in Porous Electrodes of Proton Exchange Membrane Fuel Cells Using the Interdigitated Gas Distributors

Multicomponent Transport in Porous Electrodes of Proton Exchange Membrane Fuel Cells Using the Interdigitated Gas Distributors

An Along‐the‐Channel Model for Proton Exchange Membrane Fuel Cells

CO-free fuel processing for fuel cell applications

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