Thermomechanical stability and inelastic energy dissipation as durability criteria for fuel cell gas diffusion media with pre-assembly effects

The role of gas diffusion media with differently structured properties have been examined with emphasis on the liquid water saturation within the cathode of a proton exchange membrane fuel cell (PEMFC). The cathode electrode consists of a gas diffusion layer (GDL), a micro-porous layer and a catalyst layer (CL). The liquid water saturation profiles have been calculated for varying structural and physical properties, i.e., porosity, permeability, thickness and contact angle for each of these layers. It has been observed that each layer has its own role in determining the liquid water saturation within the CL. Among all the layers, the GDL is the most influential layer that governs the transport phenomena within the PEMFC cathode. Besides, the thickness of the CL also affects the liquid water saturation and it should be carefully controlled.

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The Effect of Catalyst Coated Diffusion Media on PEM Fuel Cell Performance

Volume 9: Heat Transfer, Fluid Flows, and Thermal Systems, Parts A, B and C ◽

10.1115/imece2009-11597 ◽

2009 ◽

Cited By ~ 2

Author(s):

Derek W. Fultz ◽

Po-Ya Abel Chuang

Keyword(s):

Fuel Cell ◽

Proton Exchange Membrane ◽

Thermal Contact ◽

Electrical Contact ◽

Gas Diffusion ◽

Proton Exchange ◽

Hot Press ◽

Fuel Cell Performance ◽

Diffusion Media ◽

A Cell

Two fuel cell architectures, differing only by the surfaces onto which the electrodes were applied, have been analyzed to determine the root causes of dissimilarities in performance. The basic proton exchange membrane fuel cell (PEMFC) is comprised of the proton transporting membrane, platinum-containing anode and cathode electrodes, porous carbon fiber gas diffusion media (GDM), and flow fields which deliver the reactant hydrogen and air flows. As no optimal cell design currently exists, there is a degree of latitude regarding component assembly and structure. Catalyst coated diffusion media (CCDM) refers to a cell architecture option where the electrode layers are coated on the GDM layers and then hot-pressed to the membrane. Catalyst coated membrane (CCM) refers to an architecture where the electrodes are transferred directly onto the membrane. A cell with CCDM architecture has tightly bonded interfaces throughout the assembly which can result in lower thermal and electrical contact resistances. Considering the fuel cell as a 1-D thermal system, the through-plane thermal resistance was observed to decrease by 5–10% when comparing CCDM to CCM architectures. This suggests the thermal contact resistance at the electrode interfaces was significantly reduced in the hot-press process. In addition, the electrical contact resistances between the electrode and GDM were observed to be significantly reduced with a CCDM architecture. This study shows that these effects, which have a potential to increase performance, can be attributed to the hot-press lamination process and use of CCDM architecture.

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Optimization of Perfluoropolyether-Based Gas Diffusion Media Preparation for PEM Fuel Cells

Energies ◽

10.3390/en13071831 ◽

2020 ◽

Vol 13 (7) ◽

pp. 1831 ◽

Cited By ~ 1

Author(s):

Riccardo Balzarotti ◽

Saverio Latorrata ◽

Marco Mariani ◽

Paola Gallo Stampino ◽

Giovanni Dotelli

Keyword(s):

Fuel Cell ◽

Electrochemical Impedance ◽

Pem Fuel Cells ◽

Gas Diffusion ◽

Cathode Side ◽

Porous Substrate ◽

Materials Properties ◽

Electrochemical Tests ◽

Electrochemical Parameters ◽

Diffusion Media

A hydrophobic perfluoropolyether (PFPE)-based polymer, namely Fluorolink® P56, was studied instead of the commonly used polytetrafluoroethylene (PTFE), in order to enhance gas diffusion media (GDM) water management behavior, on the basis of a previous work in which such polymers had already proved to be superior. In particular, an attempt to optimize the GDM production procedure and to improve the microporous layer (MPL) adhesion to the substrate was carried out. Materials properties have been correlated with production routes by means of both physical characterization and electrochemical tests. The latter were performed in a single PEM fuel cell, at different relative humidity (namely 80% on anode side and 60%/100% on cathode side) and temperature (60 °C and 80 °C) conditions. Additionally, electrochemical impedance spectroscopy measurements were performed in order to assess MPLs properties and to determine the influence of production procedure on cell electrochemical parameters. The durability of the best performing sample was also evaluated and compared to a previously developed benchmark. It was found that a final dipping step into PFPE-based dispersion, following MPL deposition, seems to improve the adhesion of the MPL to the macro-porous substrate and to reduce diffusive limitations during fuel cell operation.

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Pairing Asymmetric Gas Diffusion Media for High-Power Fuel Cell Operation

ECS Meeting Abstracts ◽

10.1149/ma2019-02/32/1428 ◽

2019 ◽

Keyword(s):

Fuel Cell ◽

High Power ◽

Gas Diffusion ◽

Diffusion Media ◽

Fuel Cell Operation

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Operation of a proton-exchange membrane fuel cell under non-humidified conditions using thin cast Nafion membranes with different gas-diffusion media

Journal of Power Sources ◽

10.1016/j.jpowsour.2005.06.023 ◽

2006 ◽

Vol 156 (2) ◽

pp. 294-299 ◽

Cited By ~ 25

Author(s):

S. Vengatesan ◽

H.-J. Kim ◽

E.A. Cho ◽

S.U. Jeong ◽

H.Y. Ha ◽

...

Keyword(s):

Fuel Cell ◽

Proton Exchange Membrane ◽

Gas Diffusion ◽

Proton Exchange ◽

Diffusion Media ◽

Nafion Membranes ◽

Exchange Membrane

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Analysis of liquid water transport in fuel cell gas diffusion media using two-mobile phase pore network simulations

Journal of Power Sources ◽

10.1016/j.jpowsour.2010.11.008 ◽

2011 ◽

Vol 196 (5) ◽

pp. 2725-2734 ◽

Cited By ~ 13

Author(s):

B. Markicevic ◽

N. Djilali

Keyword(s):

Fuel Cell ◽

Water Transport ◽

Liquid Water ◽

Mobile Phase ◽

Pore Network ◽

Gas Diffusion ◽

Diffusion Media ◽

Network Simulations ◽

Liquid Water Transport

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Effects of Flow Field and Diffusion Layer Properties on Water Accumulation in a PEM Fuel Cell

ASME 5th International Conference on Nanochannels, Microchannels, and Minichannels ◽

10.1115/icnmm2007-30142 ◽

2007 ◽

Cited By ~ 1

Author(s):

J. P. Owejan ◽

T. A. Trabold ◽

D. L. Jacobson ◽

M. Arif ◽

S. G. Kandlikar

Keyword(s):

Fuel Cell ◽

Flow Field ◽

Pem Fuel Cell ◽

Gas Diffusion ◽

Proton Exchange ◽

Cell Performance ◽

Water Volume ◽

Fuel Cell Performance ◽

Diffusion Media ◽

And Diffusion

Water is the main product of the electrochemical reaction in a proton exchange membrane (PEM) fuel cell. Where the water is produced over the active area of the cell, and how it accumulates within the flow fields and gas diffusion layers, strongly affects the performance of the device and influences operational considerations such as freeze and durability. In this work, the neutron radiography method was used to obtain two-dimensional distributions of liquid water in operating 50 cm2 fuel cells. Variations were made of flow field channel and diffusion media properties, to assess the effects on the overall volume and spatial distribution of accumulated water. Flow field channels with hydrophobic coating retain more water, but the distribution of a greater number of smaller slugs in the channel area improves fuel cell performance at high current density. Channels with triangular geometry retain less water than rectangular channels of the same cross-sectional area, and the water is mostly trapped in the two corners adjacent to the diffusion media. Also, it was found that cells constructed using diffusion media with lower in-plane gas permeability tended to retain less water. In some cases, large differences in fuel cell performance were observed with very small changes in accumulated water volume, suggesting that flooding within the electrode layer or at the electrode-diffusion media interface is the primary cause of the significant mass transport voltage loss.

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GDM Intrusion Into Reactant Gas Channels and the Effect on Fuel Cell Performance

ASME 2006 Fourth International Conference on Fuel Cell Science, Engineering and Technology, Parts A and B ◽

10.1115/fuelcell2006-97086 ◽

2006 ◽

Cited By ~ 2

Author(s):

Pinkhas Rapaport ◽

Yeh-Hung Lai ◽

Chunxin Ji

Keyword(s):

Fuel Cell ◽

Gas Flow ◽

Flow Distribution ◽

Pem Fuel Cell ◽

Pem Fuel Cells ◽

Gas Diffusion ◽

Cell Performance ◽

Fuel Cell Performance ◽

Diffusion Media ◽

Reactant Flow

This paper reports on the study of gas diffusion media (GDM) intrusion into reactant gas channels and its effect on the performance of the proton exchange membrane (PEM) fuel cell. The PEM fuel cell under consideration consists of a membrane electrode assembly (MEA) sandwiched between two layers of gas diffusion media commonly made of carbon paper or cloth. The GDM/MEA/GDM assembly is then compressed between two adjacent bi-polar plates. In this configuration, the compression pressure is transmitted under the lands of the reactant gas flow-field onto GDMs on which the portion over the channels remain unsupported. Because of the relatively low bending and compressive stiffness, it is found that GDMs can easily intrude into the reactant gas channels. The direct consequence of GDM intrusion is the pressure drop increase in the reactant gases in the intruded channels. This is further compounded by cell-to-cell or channel-to-channel variation in GDM thickness and mechanical properties, which results in non-uniform reactant gas flow distribution and ultimately negatively impacts the fuel cell performance. In this study, we have developed a GDM intrusion model based on the finite element method (FEM. We have also devised an experimental setup to measure the GDM intrusion, in which we found good agreement between the model prediction and experimental measurement. Combining the FEM based intrusion model and a flow redistribution model we have investigated the effect of GDM channel intrusion on the reactant flow distribution and the impact on the fuel cell performance. It is found that a 20% reduction of reactant flow can be induced with a 5% additional blockage in channels by GDM intrusion. Based on the findings from the current study, we attribute the significant performance variation in a 30-cell fuel cell stack to the variation in reactant flow induced by the variation in GDM intrusion. The results from the analytical study and fuel cell testing both suggested that the product variations in GDM would need to be significantly reduced and the stiffness of the GDM would need to be increased if the PEM fuel cells of high power density were to be used reliably at a relatively low stoichiometry.

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