System design for vehicle applications: Daimler Chrysler

Konrad, G. T.; Sommer, M.; Loschko, Birgit; Schell, Andreas; Docter, Andreas

doi:10.1002/9780470974001.f303058

Cited by 5 publications

(7 citation statements)

References 4 publications

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“…PEMFCs are compact systems characterized by a very high energy conversion efficiency, up to 2e3 times larger in comparison with competing technologies such as internal combustion engines (ICEs) [5]. PEMFCs are particularly suitable to power light-duty electric vehicles and portable electronic devices such as audiovisual players and laptop computers [6,7]. One of the most important bottlenecks in the operation of PEMFCs is the sluggish kinetics of the oxygen reduction reaction (ORR) [8].…”

Section: Introductionmentioning

confidence: 99%

Synthesis, studies and fuel cell performance of “core–shell” electrocatalysts for oxygen reduction reaction based on a PtNix carbon nitride “shell” and a pyrolyzed polyketone nanoball “core”

Noto

Negro

Polizzi

et al. 2014

International Journal of Hydrogen Energy

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Section: Introductionmentioning

confidence: 99%

Synthesis, studies and fuel cell performance of “core–shell” electrocatalysts for oxygen reduction reaction based on a PtNix carbon nitride “shell” and a pyrolyzed polyketone nanoball “core”

Noto

Negro

Polizzi

et al. 2014

International Journal of Hydrogen Energy

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“…Water transport is an essential element of polymer electrolyte membrane (PEM) fuel cell operation. − Liquid water that is formed at a catalyst/membrane interface is pushed through porous electrodes into gas flow channels. The water drops emerge from the largest pores in the electrode, and grow in the channel.…”

Section: Introductionmentioning

confidence: 99%

Drop Detachment and Motion on Fuel Cell Electrode Materials

Gauthier

Hellstern

Kevrekidis

et al. 2012

ACS Appl. Mater. Interfaces

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Liquid water is pushed through flow channels of fuel cells, where one surface is a porous carbon electrode made up of carbon fibers. Water drops grow on the fibrous carbon surface in the gas flow channel. The drops adhere to the superficial fiber surfaces but exhibit little penetration into the voids between the fibers. The fibrous surfaces are hydrophobic, but there is a substantial threshold force necessary to initiate water drop motion. Once the water drops begin to move, however, the adhesive force decreases and drops move with minimal friction, similar to motion on superhydrophobic materials. We report here studies of water wetting and water drop motion on typical porous carbon materials (carbon paper and carbon cloth) employed in fuel cells. The static coefficient of friction on these textured surfaces is comparable to that for smooth Teflon. But the dynamic coefficient of friction is several orders of magnitude smaller on the textured surfaces than on smooth Teflon. Carbon cloth displays a much smaller static contact angle hysteresis than carbon paper due to its two-scale roughness. The dynamic contact angle hysteresis for carbon paper is greatly reduced compared to the static contact angle hysteresis. Enhanced dynamic hydrophobicity is suggested to result from the extent to which a dynamic contact line can track topological heterogeneities of the liquid/solid interface. KEYWORDS: contact angle, hydrophobic, carbon, wetting, carbon fibers, contact angle hysteresis, Teflon ■ INTRODUCTIONWater transport is an essential element of polymer electrolyte membrane (PEM) fuel cell operation. 1−5 Liquid water that is formed at a catalyst/membrane interface is pushed through porous electrodes into gas flow channels. The water drops emerge from the largest pores in the electrode, and grow in the channel. Initially, the drops are held in place by adhesion to the water column in the electrode pore, but as the drops grow surface contact with the porous electrode and surface contact with the walls of the flow channel are the dominate adhesive forces. The drop must be detached and pushed through the gas flow channel in contact with the electrode surface to be removed from the fuel cell. Efficient fuel cell operation requires removal of liquid water drops from the fuel cell with minimal work. The surface properties of the porous electrode play a key role in the energy required to remove water drops from the gas flow channels of the fuel cell. We have been devising experiments to isolate the flow resistances for water transport through the porous electrode and gas flow channel. 6−8 The porous electrode is required to carry the electron current from the electrocatalyst to the external circuit. 9 It must also permit transport of gas reactants and liquid product between the gas flow channels and the catalyst/PEM interface. 4,10,11 The porous electrode, or gas diffusion layer (GDL), of the fuel cell is typically made from carbon fibers, either as a random sheet of fibers in the form of carbon paper or as a woven arr...

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“…Fuel feeding can be a source of important power consumption, especially in the case of high operating pressure [14]. If P syst is the net electric power to be delivered by the PEMFC assembly and Z aux the efficiency characterizing the power consumption by auxiliaries, the power that must be provided by the stack is then given by [15]:…”

Section: Performances Of the Pemfcmentioning

confidence: 99%

“…In order to obtain the net assembly efficiency, fuel utilization, denoted here Z proc for fuel processing, must also be taken into account so that [15]:…”

Section: Performances Of the Pemfcmentioning

confidence: 99%

“…In order to comply with a standard norm, the NEDC that is used in the European Union is 748 adopted in the present study. The adopted cycle, which is shown in Figure 2, is the standard cycle for vehicles of admitted gross weight less then 3.5 ton and is 11 km long [15]. The total mass of the vehicle M v must take into account the additional weight of the passengers, fuel and load so that:…”

Section: Selection Of the Vehicle And Driving Cyclementioning

confidence: 99%

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Estimation of indirect CO2 emissions of a hydrogen-powered medium size vehicle for the NEDC cycle

Messaoudene

Slimani

Abdi

et al. 2009

Int. J. Energy Res.

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SUMMARYReduction in greenhouse effect gases emission is a major source of concern nowadays. Internal combustion engines, as the most widely used power generation mean for transportation, represent a large share of such gases, which motivates active research efforts for alternative solutions. In this regard, PEM fuel cells represent a promising prospect and are thoroughly investigated, whether experimentally or through numerical simulation.The present work presents a simulation of the power potential of a PEM fuel cell, which is integrated to the full power electric traction chain of a medium size car. The cell potential is modelled by taking into account the different types of polarization. The driving performances of the vehicle and its hydrogen consumption are evaluated through a simple mathematical model and an application is performed for the New European Driving Cycle (NEDC) standard driving cycle. A preliminary sizing of the proton exchange membrane fuel cell (PEMFC) membrane area for the chosen vehicle is presented, along with that of a hydrogen storage tank for a typical autonomy. The main goal of the simulation is to estimate CO 2 indirect emissions due to the production of the needed hydrogen for the cycle via an electrolyser, compared with the case of a gasoline fueled vehicle. This is performed solely on a 'fuel tank to wheel' basis in order to have comparable figures. The results indicate that the environmental advantage of hydrogen cars is quite questionable if hydrogen is produced using carbon-based energy sources.

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System design for vehicle applications: Daimler Chrysler

Cited by 5 publications

References 4 publications

Synthesis, studies and fuel cell performance of “core–shell” electrocatalysts for oxygen reduction reaction based on a PtNix carbon nitride “shell” and a pyrolyzed polyketone nanoball “core”

Synthesis, studies and fuel cell performance of “core–shell” electrocatalysts for oxygen reduction reaction based on a PtNix carbon nitride “shell” and a pyrolyzed polyketone nanoball “core”

Drop Detachment and Motion on Fuel Cell Electrode Materials

Estimation of indirect CO2 emissions of a hydrogen-powered medium size vehicle for the NEDC cycle

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