The Influence of a Novel Bio-Cell Flow Field Pattern on the Performance and Operating Conditions for a PEM Fuel Cell

Author(s):  
Fang-Bor Weng ◽  
Ay Su ◽  
Kai-Fan Lo ◽  
Cheng-Hsin Tu

A novel bio-cell flow field pattern is experimentally investigated by determining fuel cell performance and optimal operating conditions. The cell performance is analyzed by the polarization curve and the long-term stability. The bio-cell flow channel structure has a main feed track, a secondary branch track, and repeats to promote water removal from gas diffusion layer. The performance of the bio-cell flow field pattern is optimal performance when the cell is operated with low humidity gases and low cell temperature. In addition, the bio-cell flow field exhibits stable performance for non-humidified air. The fuel cell with the novel bio-cell flow field has advantages for low relative humidity operations. The results of the bio-cell flow field could potentially simplify fuel cell system design without humidifiers.

2014 ◽  
Vol 804 ◽  
pp. 75-78 ◽  
Author(s):  
Vinh Nguyen Duy ◽  
Jung Koo Lee ◽  
Ki Won Park ◽  
Hyung Man Kim

Flow-field design affects directly to the PEM fuel cell performance. This study aims to stimulate the under-rib convection by adding sub-channels and by-passes to the conventional-advanced serpentine flow-field to improve the PEM fuel cell performance. The experimental results show that if reacting gases flow in the same direction as the neighboring main channels, the under-rib convection shows a flow from the main channels to the sub-channels makes progress in reducing pressure drop and enhancing uniform gas supply and water diffusion. Alternatively, if in the direction opposite to that of the neighboring main channels, the under-rib convection shows a flow from the inlet side towards the outlet side across the sub-channel as in the conventional serpentine channels. Analyses of the local transport phenomena in the cell suggest that the inlet by-pass supplies the reacting gases uniformly from the entrance into the sub-channels and the outlet by-pass enhances water removal. Novel serpentine flow-field pattern employing sub-channels and by-passes shows uniform current density and temperature distribution by uniformly supplying the reacting gas. Furthermore, performance improvement of around 20% is observed from the experimental performance evaluation. As a result, longer battery life is expected by reducing the mechanical stress of membrane electrode assembly.


Author(s):  
J. P. Owejan ◽  
T. A. Trabold ◽  
D. L. Jacobson ◽  
M. Arif ◽  
S. G. Kandlikar

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.


2010 ◽  
Vol 447-448 ◽  
pp. 559-563 ◽  
Author(s):  
Misran Erni ◽  
Wan Ramli Wan Daud ◽  
Edy Herianto Majlan

Flow field design has several functions that should perform simultaneously. Therefore, specific plate materials and channel designs are needed to enhance the performance of proton exchange membrane (PEM) fuel cell. Serpentine flow field design is one of the most popular channel configurations for PEM fuel cell system. Some configurations have been developed to improve the cell performance. This paper presents a review on serpentine flow field (SFF) design and its influence to PEM fuel cell performance based on some indicators of performance. The comparisons of SFF with other flow field designs are summarized. The results of some experimental and numerical investigations are also presented.


2018 ◽  
Vol 197 ◽  
pp. 08010 ◽  
Author(s):  
A'rasy Fahruddin ◽  
Djatmiko Ichsani ◽  
Fadlilatul Taufany

Baffles in the Polymer Electrolyte Membrane (PEM) fuel cell flow field increase the reactant pressure to gas diffusion layer, enhance reactant mass transfer to the catalyst layer and water discharge under the rib, which in turn improve cell performance. In this study, we perform numerical simulations to investigate triangular baffles configuration in triple serpentine flow fields and compare it with flow field without baffles on cell performance. A 9-layer PEM fuel cell model with 14 cm2 active area is used. Baffles are arranged in line with single row and two rows transversely to the flow direction. Different flowrate is applied for optimization. In addition, the use of reducers in exhaust is also studied. The results show that flow field with baffles configuration can improve power density by 8%, while current density increase 6% when compared to non-baffles flow field.


Author(s):  
Luis Breziner ◽  
Peter Strahs ◽  
Parsaoran Hutapea

The objective of this research is to analyze the effects of vibration on the performance of hydrogen PEM fuel cells. It has been reported that if the liquid water transport across the gas diffusion layer (GDL) changes, so does the overall cell performance. Since many fuel cells operate under a vibrating environment –as in the case of automotive applications, this may influence the liquid water concentration across the GDL at different current densities, affecting the overall fuel cell performance. The problem was developed in two main steps. First, the basis for an analytical model was established using current models for water transport in porous media. Then, a series of experiments were carried, monitoring the performance of the fuel cell for different parameters of oscillation. For sinusoidal vibration at 10, 20 and 50Hz (2 g of magnitude), a decrease in the fuel cell performance by 2.2%, 1.1% and 1.3% was recorded when compared to operation at no vibration respectively. For 5 g of magnitude, the fuel cell reported a drop of 5.8% at 50 Hz, whereas at 20 Hz the performance increased by 1.3%. Although more extensive experimentation is needed to identify a relationship between magnitude and frequency of vibration affecting the performance of the fuel cell as well as a throughout examination of the liquid water formation in the cathode, this study shows that sinusoidal vibration, overall, affects the performance of PEM fuel cells.


2006 ◽  
Vol 4 (3) ◽  
pp. 365-368 ◽  
Author(s):  
Guo-Bin Jung ◽  
Ay Su ◽  
Cheng-Hsin Tu ◽  
Fang-Bor Weng ◽  
Shih-Hung Chan

The flow-field design of direct methanol fuel cells (DMFCs) is an important subject about DMFC performance. Flow fields play an important role in the ability to transport fuel and drive out the products (H2O,CO2). In general, most fuel cells utilize the same structure of flow field for both anode and cathode. The popular flow fields used for DMFCs are parallel and grid designs. Nevertheless, the characteristics of reactants and products are entirely different in anode and cathode of DMFCs. Therefore, the influences of flow fields design on cell performance were investigated based on the same logic with respect to the catalyst used for cathode and anode nonsymmetrically. To get a better and more stable performance of DMFCs, three flow fields (parallel, grid, and serpentine) utilized with different combinations were studied in this research. As a consequence, by using parallel flow field in the anode side and serpentine flow-field in the cathode, the highest power output was obtained.


Author(s):  
Nicola Zuliani ◽  
Rodolfo Taccani ◽  
Robert Radu

High temperature PEM (HTPEM) fuel cell based on polybenzimidazole polymer (PBI) and phosphoric acid, can be operated at temperature between 120°C and 180°C. Reactants humidification is not required and CO content up to 1% in fuel can be tolerated, affecting only marginally performance. This is what makes HTPEM fuel cells very attractive, as low quality reformed hydrogen can be used and water management problems are avoided. This paper aims to present the preliminary experimental results obtained on a HTPEM fuel cell fed with LPG using a compact steam reformer. The analysis focus on the reformer start up transient, on the influence of the steam to carbon ratio on reformate CO content and on the single fuel cell performance at different operating conditions. By analyzing the mass and energy balances of the fuel processor, fuel cell system, and balance-of-plant, a previously developed system simulation model has been used to provide critical assessment on the conversion efficiency for a 1 kWel system. The current study attempts to extend the previously published analyses of integrated HTPEM fuel cell systems.


Author(s):  
M. Minutillo ◽  
E. Jannelli ◽  
F. Tunzio

The main objective of this study is to evaluate the performance of a proton exchange membrane (PEM) fuel cell generator operating for residential applications. The fuel cell performance has been evaluated using the test bed of the University of Cassino. The experimental activity has been focused to evaluate the performance in different operating conditions: stack temperature, feeding mode, and fuel composition. In order to use PEM fuel cell technology on a large scale, for an electric power distributed generation, it could be necessary to feed fuel cells with conventional fuel, such as natural gas, to generate hydrogen in situ because currently the infrastructure for the distribution of hydrogen is almost nonexistent. Therefore, the fuel cell performance has been evaluated both using pure hydrogen and reformate gas produced by a natural gas reforming system.


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