scholarly journals Performance Enhancement of PEM Fuel Cells with an Additional Outlet in the Parallel Flow Field

Processes ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 2061
Author(s):  
Yan Zhang ◽  
Chenpeng Liu ◽  
Zhongmin Wan ◽  
Chen Yang ◽  
Shi Li ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Flow Field ◽  
Performance Enhancement ◽  
Water Saturation ◽  
Pem Fuel Cells ◽  
Gas Diffusion ◽  
Parallel Flow ◽  
Proton Exchange ◽  
Optimal Position ◽  
Target Side

The design of bipolar plates is critical for improving the performance of proton exchange membrane fuel cells (PEMFCs). In this research, a new additional outlet based on a PEMFC’s parallel flow field was proposed, and three different positions of outlet were designed on the target side of gas flowing in parallel channels. The results revealed that the additional outlets are able to increase the gas speed through channels near the additional outlets, which results in a lower water saturation and a more uniform distribution of oxygen concentration at the interface between the catalyst layer (CL) and gas diffusion layer (GDL). With the variation of the outlet position in the target side, it was found that the additional outlet set in the middle of the target side exhibits the highest increase of peak power density, namely, 13%. Furthermore, the optimal position of the additional outlet was proved to be suitable for PEMFCs with various active surface areas, indicating the universality of the present results in the study.

Separate Measurement of Current Density Under the Channel and the Shoulder in PEM Fuel Cells

2007 ◽  
Author(s):  
Lin Wang ◽  
Hongtan Liu
Keyword(s):  
Fuel Cells ◽  
Diffusion Layer ◽  
Current Density ◽  
Electrical Resistance ◽  
High Current Density ◽  
Gas Diffusion Layer ◽  
Pem Fuel Cells ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Experimental Results

In a proton exchange membrane (PEM) fuel cell current density under the shoulder can be very different from that under the gas channel and the knowledge of where the current density is higher is critical in flow field designs in order to optimize cell performance. Yet, up to date this issue has not been resolved. In this study, a novel yet simple approach was adopted to directly measure the current densities under the channel and the shoulder in PEM fuel cells separately. In this approach, the cathode catalyst layer was so designed that either the area under the shoulder or the area under the channel was loaded with catalyst. Such a design guaranteed the currents generated under the shoulder and the channel could be measured separately. Experimental results showed that the current density produced under the channel was lower than that under the shoulder except in the high current density region. To determine whether the lateral electrical resistance of the gas diffusion layer (GDL) was the causes for lower current density under the channel, an additional set of experiments were conducted. In this set of experiments, a silver mesh was added on the top of the gas diffusion layer (GDL) and the experimental results showed that GDL lateral electrical resistance was not the cause and it had a negligible effect on lateral current density distribution.

Three Dimensional Analysis of Transport and Reaction in Proton Exchange Membrane Fuel Cells

2000 ◽  
Author(s):  
Sukkee Um ◽  
C. Y. Wang
Keyword(s):  
Fuel Cells ◽  
Flow Field ◽  
Proton Exchange Membrane ◽  
Computational Study ◽  
Three Dimensional ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Serpentine Flow Field ◽  
Interdigitated Flow Field ◽  
Exchange Membrane

Abstract A three-dimensional computational study based on the finite volume method is carried out for proton exchange membrane (PEM) fuel cells with a Nation 117 membrane and an interdigitated flow field on the cathode. Emphasis is placed on obtaining a fundamental understanding of fully three-dimensional flow in the air cathode and how it impacts the transport and electrochemical reaction processes. For the first time, fully three-dimensional results of the flow structure, species profiles and current distribution are presented for PEM fuel cells with the interdigitated flow field. The model results show that forced convection induced by the interdigitated flow field in the backing layer substantially improves mass transport of oxygen to, and water removal from, the reaction zone thus leading to a higher cell current density as compared to that of the serpentine flow field. The computations also indicate a need to account for water condensation and ensuing gas-liquid two-phase flow and transport in the porous cathode at high current densities. The present computer model can be used as a design or diagnostic tool for fuel cell cathodes with complex structural flow fields.

GOLD-PLATED TITANIUM VS CARBON-IMPLANTED TITANIUM AS MATERIAL FOR BIPOLAR PLATES IN PEM FUEL CELLS

2019 ◽  
Vol 26 (08) ◽  
pp. 1950038
Author(s):  
M. S. VLASKIN ◽  
A. V. GRIGORENKO ◽  
E. I. SHKOLNIKOV ◽  
A. S. ILYUKHIN
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Performance Enhancement ◽  
Precious Metals ◽  
Pem Fuel Cells ◽  
Gas Diffusion ◽  
Electrical Performance ◽  
Carbon Ions ◽  
Bipolar Plates ◽  
Gold Plating

Three different types of current-collecting plates for air-hydrogen PEM fuel cell were manufactured and tested: unmodified titanium plates; gold-plated titanium plates and titanium plates treated by carbon ions implantation. It was shown that the applied surface modifications reduce contact resistance between titanium plate and carbon gas diffusion layer. Total ohmic resistance of fuel cell is reduced by 1.8 and 1.4 times in case of gold-plated titanium and carbon-implanted titanium, respectively, in comparison with uncoated titanium. Although gold plating turned out to be more profitable than carbon ion implantation in terms of electrical characteristics, in the last case, the performance enhancement was reached without using precious metals, which at mass production must play more important role. This technology promises to reduce the cost of bipolar plates manufacturing, while maintaining high electrical performance of PEM fuel cells.

Measuring Critical Velocity of Water Droplet Removal on Gas Diffusion Layers of Proton Exchange Membrane Fuel Cells

2013 ◽  
Author(s):  
Caymen Novak ◽  
Emily Hsu ◽  
Richard Schuster ◽  
Xia Wang
Keyword(s):  
Fuel Cells ◽  
Critical Velocity ◽  
Water Droplet ◽  
Proton Exchange Membrane ◽  
Droplet Diameter ◽  
Pem Fuel Cells ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Diffusion Layers ◽  
Exchange Membrane

The production of water on the cathode electrode of proton exchange membrane (PEM) fuel cells may cause problems with flooding or freezing of cell. Therefore, there is a need for water management. This study investigates water droplet removal on the gas diffusion layer by measuring critical velocity-the velocity needed to remove droplets formed above the GDL. A test apparatus was designed for this study, and the effects of droplet diameter, GDL thickness, and PTFE (polytetrafluoroethylene) loading on the critical velocity were studied. When droplet diameter and PTFE loading were increased, a decrease in critical velocity was observed. However, as GDL thickness increased, depending on the PTFE loading, either an increase or decrease in critical velocity was observed. Thus, it was concluded that increased droplet diameter and increased PTFE loading result in lower critical velocities, increasing thickness results in lower critical velocity for low PTFE loadings, and increasing thickness does not have a significant effect on the critical velocity for high PTFE loadings. This work increases the understanding of designing an optimum GDL in the fuel cell, while also providing insight on the critical velocity needed to remove water droplets from the GDL.

scholarly journals Effective Technique for Improving Electrical Performance and Reliability of Fuel Cells

2017 ◽  
Vol 8 (4) ◽  
pp. 1868
Author(s):  
A. Albarbar ◽  
M. Alrweq
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Water Content ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Pem Fuel Cells ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Electrical Performance ◽  
And Performance

To optimise the electrical performance of proton exchange membrane (PEM) fuel cells, a number of factors have to be precisely monitored and controlled. Water content is one of those factors that has great impact on reliability, durability and performance of PEM fuel cells. The difficulty in controlling water content lies in the inability to determine correct level of water accumulated inside the fuel cell. In this paper, a model-based technique, implemented in COMSOL, is presented for monitoring water content in PEM fuel cells. The model predicts, in real time, water content taking account of other processes occurring in gas channels, across gas diffusion layers (GDL), electrodes, and catalyst layer (CL) and within the membrane to minimize voltage losses and performance degradation. The level of water generated is calculated as function of cell’s voltage and current. Model’s performance and accuracy are verified using a transparent 500 mW PEM fuel cell. Results show model predicted current and voltage curves are in good agreement with the experimental measurements. The unique feature of this model is that, no special requirements are needed as only current, and voltage of the PEM fuel cell were measured thus, is expected to pave the path for developing non-intrusive control and monitoring systems for fuel cells.

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