A Metric for Characterization of Multifunctional Fuel Cell Designs

2011 ◽  
Vol 8 (5) ◽  
Author(s):  
Corydon D. Hilton ◽  
Daniel M. Peairs ◽  
John J. Lesko ◽  
Scott W. Case
Keyword(s):  
Fuel Cell ◽  
Order Theory ◽  
Gas Diffusion ◽  
System Level ◽  
Specific Power ◽  
Structural Cell ◽  
Structural Support ◽  
Model Cell ◽  
Electrical Component ◽  
Specific Power Density

The U.S. Army has investigated a variety of multifunctional designs in order to achieve system level mass and/or volume savings. One of the multifunctional devices developed is the multifunctional fuel cell (MFC)—a fuel cell which simultaneously provides a system with structural support and power generation. However, there are no established methods for measuring how well a particular design performs or its multifunctional advantage. The current paper presents a metric by which multifunctional fuel cell designs can be characterized. The mechanical aspect of the metric is based on the specific bending stiffness of the structural cell and is developed using Frostig’s high-order theory. The electrical component of the metric is based on the specific power density achieved by the structural cell. The structural systems considered here display multifunctional efficiencies ranging from 22% to 69%. The higher efficiency was obtained by optimizing the contact pressure at the gas diffusion layer (GDL) in a model cell design. The efficiencies obtained suggest the need for improved multifunctional designs in order to reach system level mass savings.

Flexible and Lightweight Fuel Cell with High Specific Power Density

ACS Nano ◽  
2017 ◽  
Vol 11 (6) ◽  
pp. 5982-5991 ◽  
Author(s):  
Fandi Ning ◽  
Xudong He ◽  
Yangbin Shen ◽  
Hehua Jin ◽  
Qingwen Li ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Power Density ◽  
Specific Power ◽  
High Specific Power ◽  
Specific Power Density

Water Crossover Experiments in an Open-Cathode Direct Methanol Fuel Cell

2011 ◽  
Author(s):  
C. C. Kuo ◽  
L. M. Neal ◽  
O. D. Crisalle ◽  
W. E. Lear ◽  
J. H. Fletcher
Keyword(s):  
Water Vapor ◽  
Fuel Cell ◽  
Direct Methanol Fuel Cell ◽  
Carbon Dioxide Concentration ◽  
Gas Diffusion ◽  
System Level ◽  
Transport Parameter ◽  
Water Recovery ◽  
Direct Methanol ◽  
Methanol Fuel Cell

A direct methanol fuel cell (DMFC) that does not require an external water feed or a powered water-recovery system has potential for wide application in portable electronic devices. This paper provides experimental data for the water recovery rate in a novel DMFC design featuring a hydrophobic cathode gas-diffusion layer that allows for passive water recovery. Water and methanol crossover rates were experimentally characterized by measuring the water vapor and carbon dioxide concentration at the cathode exit with an infrared sensor. The result showed that the mass-transport parameter of water vapor, increases linearly with increasing cell temperature and remains invariant with respect to the cell current density. Water neutrality of the DMFC stack was achieved while the cell operated close to 50 °C and 150 mA/cm2 with a 1M methanol solution. A comprehensive empirical equation based on the experimental results is presented, along with system-level insights into the controllability of water management in designing an open cathode DMFC system.

scholarly journals Performance of Sulfide-Driven Fuel Cell Aerated by Venturi Tube Ejector

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 694
Author(s):  
Venko N. Beschkov ◽  
Elena N. Razkazova-Velkova ◽  
Martin S. Martinov ◽  
Stefan M. Stefanov
Keyword(s):  
Hydrogen Sulfide ◽  
Fuel Cell ◽  
Electric Energy ◽  
Gas Diffusion ◽  
Venturi Tube ◽  
Polluted Water ◽  
The Black Sea ◽  
High Hydrogen ◽  
Mass Transfer Limitation ◽  
Pure Graphite

Hydrogen sulfide is frequently met in natural waters, like mineral springs, but mostly it is found in marine water with low renewal rate. The Black Sea has extremely high hydrogen sulfide content. It can be utilized in different ways, but the most promising one is direct conversion into electricity. This result can be attained by a sulfide-driven fuel cell (SDFC), converting sulfide to sulfate thus releasing electric energy up to 24 GJ/t. One of the most important problems is the mass transfer limitation on oxygen transfer in the cathode space of the fuel cell. This problem can be solved using a gas diffusion electrode or highly efficient saturation by oxygen in an ejector of the Venturi tube type. This work presents experimental data in laboratory-scale SDFC for sulfide conversion into sulfate, sulfite and polysulfide releasing different amounts of electric energy. Two types of aeration are tested: direct air blow and Venturi-tube ejector. Besides pure graphite, two catalysts, i.e., cobalt spinel and zirconia-doped graphite were tested as anodes. Experiments were carried out at initial sulfide concentrations from 50 to 300 mg/L. Sulfate, sulfite and thiosulfate ions were detected in the outlet solutions from the fuel cell. The electrochemical results show good agreement with the chemical analyses. Most of the results show attained high efficiencies of the fuel cell, i.e. up to 80%. The practical applications of this method can be extended for other purposes, like treatment of polluted water together with utilization as energy.

scholarly journals Mass Transport Limitations of Water Evaporation in Polymer Electrolyte Fuel Cell Gas Diffusion Layers

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2967
Author(s):  
Adrian Mularczyk ◽  
Andreas Michalski ◽  
Michael Striednig ◽  
Robert Herrendörfer ◽  
Thomas J. Schmidt ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Liquid Water ◽  
Evaporative Cooling ◽  
Gas Diffusion ◽  
Polymer Electrolyte Fuel Cell ◽  
Ex Situ ◽  
Water Evaporation ◽  
Evaporative Water ◽  
Gas Diffusion Layers ◽  
Diffusion Layers

Facilitating the proper handling of water is one of the main challenges to overcome when trying to improve fuel cell performance. Specifically, enhanced removal of liquid water from the porous gas diffusion layers (GDLs) holds a lot of potential, but has proven to be non-trivial. A main contributor to this removal process is the gaseous transport of water following evaporation inside the GDL or catalyst layer domain. Vapor transport is desired over liquid removal, as the liquid water takes up pore space otherwise available for reactant gas supply to the catalytically active sites and opens up the possibility to remove the waste heat of the cell by evaporative cooling concepts. To better understand evaporative water removal from fuel cells and facilitate the evaporative cooling concept developed at the Paul Scherrer Institute, the effect of gas speed (0.5–10 m/s), temperature (30–60 °C), and evaporation domain (0.8–10 mm) on the evaporation rate of water from a GDL (TGP-H-120, 10 wt% PTFE) has been investigated using an ex situ approach, combined with X-ray tomographic microscopy. An along-the-channel model showed good agreement with the measured values and was used to extrapolate the differential approach to larger domains and to investigate parameter variations that were not covered experimentally.

scholarly journals Transport Parameter Correlations for Digitally Created PEFC Gas Diffusion Layers by Using OpenPNM

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1141
Author(s):  
Ángel Encalada-Dávila ◽  
Mayken Espinoza-Andaluz ◽  
Julio Barzola-Monteses ◽  
Shian Li ◽  
Martin Andersson
Keyword(s):  
Fuel Cell ◽  
Energy Conversion ◽  
Transport Phenomena ◽  
Electrical Energy ◽  
Gas Diffusion ◽  
Polymer Electrolyte Fuel Cell ◽  
Carbon Paper ◽  
Transport Parameter ◽  
Transport Parameters ◽  
Depth Analysis

A polymer electrolyte fuel cell (PEFC) is an electrochemical device that converts chemical energy into electrical energy and heat. The energy conversion is simple; however, the multiphysics phenomena involved in the energy conversion process must be analyzed in detail. The gas diffusion layer (GDL) provides a diffusion media for reactant gases and gives mechanical support to the fuel cell. It is a complex medium whose properties impact the fuel cell’s efficiency. Therefore, an in-depth analysis is required to improve its mechanical and physical properties. In the current study, several transport phenomena through three-dimensional digitally created GDLs have been analyzed. Once the porous microstructure is generated and the transport phenomena are mimicked, transport parameters related to the fluid flow and mass diffusion are computed. The GDLs are approximated to the carbon paper represented as a grouped package of carbon fibers. Several correlations, based on the fiber diameter, to predict their transport properties are proposed. The digitally created GDLs and the transport phenomena have been modeled using the open-source library named Open Pore Network Modeling (OpenPNM). The proposed correlations show a good fit with the obtained data with an R-square of approximately 0.98.

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