The proton exchange membrane (PEM) fuel cell is being investigated as an alternate power source for various applications like transportation and emergency power supplies. The paper presents a novel circuit model for a PEM fuel cell that can be used to design and analyze fuel cell power systems. The PSPICE-based model uses bipolar junction transistors (BJTs) and LC elements available in the PSPI...

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 ...

Hybrid polymer electrolyte fuel cells combine a proton exchange membrane PEM and anion exchange membrane AEM and exhibit unique advantages. The electrochemical performance and current limitations of a hybrid cell with an alkaline electrode fabricated on a Nafion membrane was characterized at 70°C as a function of relative humidity. To separate the individual characteristics of the AEM anode and...

While problems related to CO poisoning still exist for the anode, most of the efficiency loss (80%) in a fuel cell arises due to the cathode. Oxygen reduction at the cathode requires the largest amount of the catalyst in PEM fuel cells due to its lower activity. This problem needs to be solved before mass commercialization of fuel cells can be achieved. The specific objective is to synthesize n...

An effort is underway to develop a prototype Proton Exchange Membrane (PEM) Fuel Cell breadboard system for fuhlre space applications. This prototype will be used to develop a comprehensive des ign basis for a space-rated PEM fuel cell powerplant. The prototype system includes reactant pressure regulators, ejector-based reactant pumps, a 4-kW fuel cell stack and cooling system, and a passive, m...

Transients have utmost importance in the lifetime and performance degradation of PEM fuel cells. Recent studies show that cyclic transients can induce hygro-thermal fatigue. In particular, the amount of water in the membrane varies significantly during transients, and determines the ionic conductivity and the structural properties of the membrane. In this work, we present three-dimensional time...

Proton exchange membrane fuel cell technology (PEMFC) is highly suited to automotive applications since it can offer efficient energy conversion in a compact and robust package. Size and reliability are related to the simplicity of the system, which in turn is influenced by the choice of stack cooling strategy. Intelligent Energy is targeting automotive applications using evaporatively cooled s...

Modeling and Simulation of the Degradation of Perfluorinated Ion-Exchange Membranes in PEM Fuel Cells A. A. Shah, T. R. Ralph,* and F. C. Walsh* Electrochemical Engineering Laboratory, Energy Technology Research Group, School of Engineering Sciences, University of Southampton, Highfields, Southampton SO17 1BJ, United Kingdom Johnson Matthey Fuel Cells, Lydiard Fields, Great Western Way, Swindon...

The present paper explores the impact of an on-board hydrogen harvesting system (fuel reformer) on the overall efficiency of a fuel-cell powered vehicle. Various methods of hydrogen production for automotive applications have been discussed first. As the hydrogen production is one of the major challenges for application of proton exchange membrane (PEM) fuel cells, especially in vehicular indus...