Fuel cells are electrochemical energy converters which allow transformation of the chemical energy of a fuel to electricity through oxido-reduction reaction. The voltage of an elementary cell is usually near 1 V in open circuit and around 0.6 V in nominal conditions of power generation. Fuel cells are then by essence low voltage sources , so that for most practical applications, power managemen...

electrochemical impedance spectroscopy (eis) is a suitable and powerful diagnostic testing method for fuel cells (fcs) since it is non-destructive and provides useful information about fc performance and its components. in this study, for the first time, a 500w cascade type 4 cells stack with integrated humidifier, water separator and internal manifolds was designed, fabricated and tested. the ...

Start-up and dynamic responses to changes in load are reported for a dry feed, autohumidified polymer electrolyte membrane fuel cell PEMFC . The fuel cell current can be ignited by water injection; criteria are derived for the required water injection as functions of fuel cell size, temperature, and reactant feed rates. Steady-state multiplicity is observed where the fuel cell current can be ei...

This paper focuses on the energy management control strategy for a hybrid fuel cell powered vehicle. A method based on optimal control theory is presented. This control strategy has been applied to a representative hybrid PEM (Proton Exchange Membrane) fuel cell mid-size vehicle. Simulation results on a priori known driving cycle are presented and compared to a sub-optimal strategy. Copyright ©...

Proton exchange membrane fuel cells (PEMFCs) are promising devices for clean power generation in automotive, stationary, and portable applications. Perfluorosulfonic acid (PFSA) ionomers (for example, Nafion) have been the benchmark PEMs; however, several problems, including high gas permeability, low thermal stability, high production cost, and environmental incompatibility, limit the widespre...

In this paper, we demonstrate a monolithic integrated micro direct methanol fuel cell (μDMFC) for the first time. The monolithic integrated μDMFC combines proton exchange membrane (PEM) and Pt nanocatalysts, in which PEM is achieved by the functionalized porous silicon membrane and 3D Pt nanoflowers being synthesized in situ on it as catalysts. Sulfo groups functionalized porous silicon membran...

PEM (Proton Exchange Membrane) fuel cells show characteristics of high power density, low operating temperature and fast start-up capability, which make them potentially suitable to replace conventional power sources (e.g. internal combustion engines) as Auxiliary Power Units (APU) for on-board applications. This paper presents a methodology for a preliminary investigation on either sizing and ...

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...

This paper describes and demonstrates a new method for determination of current density distribution in an operating polymer electrolyte membrane ~PEM! fuel cell. The technique is a modification of the current mapping technique that relies on an array of shunt resistors embedded within a current collecting plate. Standard, nonaltered membrane electrode assemblies are utilized with gas diffusion...

A singularly perturbed model is proposed for a system comprised of a PEM Fuel Cell(PEM-FC) with Natural Gas Hydrogen Reformer (NG-HR). This eighteenth order system is decomposedinto slow and fast lower order subsystems using singular perturbation techniques that provides tools forseparation and order reduction. Then, three different types of controllers, namely an optimal full-order,a near-opti...