Gas flow field with obstacles for PEM fuel cells at different operating conditions

2015 ◽  
Vol 40 (5) ◽  
pp. 2303-2311 ◽  
Author(s):  
Muhittin Bilgili ◽  
Magdalena Bosomoiu ◽  
Georgios Tsotridis
Keyword(s):  
Fuel Cells ◽  
Flow Field ◽  
Gas Flow ◽  
Pem Fuel Cells ◽  
Operating Conditions ◽  
Gas Flow Field

Advanced Integrated Flow Field (IFF) Design for High Performance Fuel Cell and Electrolyzer

2014 ◽  
Author(s):  
Michael Pien ◽  
Steven Lis ◽  
Radha Jalan ◽  
Marvin Warshay ◽  
Suresh Pahwa
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Flow Field ◽  
Gas Flow ◽  
Pem Fuel Cells ◽  
Water Flooding ◽  
Stoichiometric Ratio ◽  
Plant Design ◽  
Two Phase ◽  
Hydrophilic Matrix

Higher efficiency operation of PEM fuel cells needs an advanced passive way to remove product water. Water flooding in gas flow channels reduces efficiency and needs to be mitigated by a support of balance of plant design and components which results in parasitic power losses. ElectroChem’s Integrated Flow Field (IFF) design with the integration of hydrophobic and hydrophilic matrix has been proven to solve these challenges with no impact on the performance. The hydrophobic and hydrophilic matrix facilitates two phase (gas and liquid) flow to and away from the interface between the electrode membrane assembly and the flow field. A phase-separation feature of the IFF allowed the fuel cells to operate on a flow rate at its consumption rate. The IFF fuel cell has demonstrated operation at the ideal one stoichiometric ratio with 100% gas utilization and orientation independent. The IFF also served as gas humidifier through the creation of simultaneous distribution of gas and water within the cell. The self-humidification capability keeps the cell operating without the humidity of the input gas. The IFF design also enhanced the performance of water electrolysis which is a reverse process of fuel cell. The IFF supported the passive water feed to the cell and gas separation from the cell.

Analysis of Water Morphology in the Active Area and Channel-to-Manifold Transitions of a PEM Fuel Cell

2014 ◽  
Author(s):  
Daniel J. Fenton ◽  
Jeffrey J. Gagliardo ◽  
Thomas A. Trabold
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Flow Field ◽  
Current Density ◽  
Liquid Water ◽  
Pem Fuel Cells ◽  
Operating Conditions ◽  
Active Area ◽  
Water Volume ◽  
Crossover Point

To achieve optimal performance of proton exchange membrane (PEM) fuel cells, effective water management is crucial. Cells need to be fabricated to operate over wide ranges of current density and cell temperature. To investigate these design and operational conditions, the present experiment utilized neutron radiography for measurement of in-situ water volumes of operating PEM fuel cells under varying operating conditions. Fuel cell performance was found to be generally inversely correlated to liquid water volume in the active area. High water concentrations restrict narrow flow field channels, limiting the reactant flow, and causing the development of performance-reducing liquid water blockages (slugs). The analysis was performed both quantitatively and qualitatively to compare the overall liquid water volume within the cell to the flow field geometry. The neutron image analysis results revealed interesting trends related to water volume as a function of time. At temperatures greater than 25°C, the total liquid water volume at start-up in the active area was the lowest at 1.5 A/cm2. At 25°C, 0.1 A/cm2 performed with the least amount of liquid water accumulation. However, as the reaction progressed at temperatures above 25°C, there was a crossover point where 0.1 A/cm2 accumulated less water than 1.5 A/cm2. The higher the temperature, the longer the time required to reach this crossover point. Results from the current density analysis showed a minimization of water slugs at 1.5 A/cm2, while the temperature analysis showed unexpectedly that, independent of current density, the condition with lowest water volume was always 35°C.

Metal-Foam Bipolar Plate for PEM Fuel Cells: Simulations and Preliminary Results

2018 ◽  
Vol 933 ◽  
pp. 342-350
Author(s):  
Yussed Awin ◽  
Nihad Dukhan
Keyword(s):  
Fuel Cells ◽  
Flow Field ◽  
Metal Foam ◽  
Bipolar Plate ◽  
Pem Fuel Cells ◽  
Unit Cell ◽  
Operating Conditions ◽  
Membrane Electrode ◽  
Computational Domain ◽  
Bipolar Plates

Bipolar plates in Proton Exchange Membrane fuel cells (PEMFC) distribute fuel and oxidant over the reactive sites of the membrane electrode assembly. In a stack, bipolar plates collect current, remove reaction products and manage water. They also separate neighboring cells and keep the oxidant and the fuel from mixing; they provide structural support to the stack. The plates are typically graphite with parallel or serpentine channels. The efficiency of a stack depends on the performance of the bipolar plates, which depends on the material and flow field design. The drawbacks of graphite include weight, fabrication inaccuracy, cost, porosity, and brittleness. Open-cell metal foam is investigated as a flow field/bipolar plate and compared to conventional graphite bipolar plates. The complex internal structure of the foam was modeled using an idealized unit cell based on a body center cube. This cell maintained the actual structural features of the foam. Clones of the idealized cell were virtually connected to each other to form the new bipolar plate. SolidWorks, and Auto-CAD were used to generate the unit cell and the computational domain, which was imported into ANSYS. Meshing of the domain produced than 350,000 elements, and 70,000 nodes. Appropriate boundary and operating conditions for PEMFC were applied, and the PEMFC module within ANSYS was used to obtain the temperature and flow distribution as well as the fuel cell performance. In comparison to conventional bipolar plates, results show that the cell current and voltage densities were improved, and temperature distribution on the membrane was even, and within the allowable limit. As importantly, there was a weight reduction of about 40% as a result of using metal foam as a bipolar plate.

scholarly journals Experimental studies on optimal operating conditions for different flow field designs of PEM fuel cells

2006 ◽  
Vol 160 (1) ◽  
pp. 284-292 ◽  
Author(s):  
Wei-Mon Yan ◽  
Ching-Hung Yang ◽  
Chyi-Yeou Soong ◽  
Falin Chen ◽  
Sheng-Chin Mei
Keyword(s):  
Fuel Cells ◽  
Flow Field ◽  
Experimental Studies ◽  
Pem Fuel Cells ◽  
Operating Conditions ◽  
Optimal Operating

scholarly journals Effects of operating conditions on cell performance of PEM fuel cells with conventional or interdigitated flow field

2006 ◽  
Vol 162 (2) ◽  
pp. 1157-1164 ◽  
Author(s):  
Wei-Mon Yan ◽  
Chi-Yen Chen ◽  
Sheng-Chin Mei ◽  
Chyi-Yeou Soong ◽  
Falin Chen
Keyword(s):  
Fuel Cells ◽  
Flow Field ◽  
Pem Fuel Cells ◽  
Operating Conditions ◽  
Cell Performance ◽  
Interdigitated Flow Field

Analytical and numerical study on cooling flow field designs performance of PEM fuel cell with variable heat flux

2016 ◽  
Vol 30 (16) ◽  
pp. 1650155 ◽  
Author(s):  
Ebrahim Afshari ◽  
Masoud Ziaei-Rad ◽  
Nabi Jahantigh
Keyword(s):  
Heat Flux ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Pressure Drop ◽  
Flow Field ◽  
Pem Fuel Cells ◽  
Coolant Flow ◽  
Temperature Uniformity ◽  
Variable Heat ◽  
Variable Heat Flux

In PEM fuel cells, during electrochemical generation of electricity more than half of the chemical energy of hydrogen is converted to heat. This heat of reactions, if not exhausted properly, would impair the performance and durability of the cell. In general, large scale PEM fuel cells are cooled by liquid water that circulates through coolant flow channels formed in bipolar plates or in dedicated cooling plates. In this paper, a numerical method has been presented to study cooling and temperature distribution of a polymer membrane fuel cell stack. The heat flux on the cooling plate is variable. A three-dimensional model of fluid flow and heat transfer in cooling plates with 15 cm × 15 cm square area is considered and the performances of four different coolant flow field designs, parallel field and serpentine fields are compared in terms of maximum surface temperature, temperature uniformity and pressure drop characteristics. By comparing the results in two cases, the constant and variable heat flux, it is observed that applying constant heat flux instead of variable heat flux which is actually occurring in the fuel cells is not an accurate assumption. The numerical results indicated that the straight flow field model has temperature uniformity index and almost the same temperature difference with the serpentine models, while its pressure drop is less than all of the serpentine models. Another important advantage of this model is the much easier design and building than the spiral models.

Effect of Operating Conditions on the Acidity of H2/Air PEM Fuel Cells' Water

2019 ◽  
Vol 16 (2) ◽  
pp. 543-550 ◽  
Author(s):  
Aboubakr M. Abdullah ◽  
Takeyoshi Okajima ◽  
F. Kitamura ◽  
Takeo Ohsaka
Keyword(s):  
Fuel Cells ◽  
Pem Fuel Cells ◽  
Operating Conditions
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