Heat and Mass Transport Analysis of Polymer Electrolyte Membrane Fuel Cell With Bipolar Plates

2009 ◽  
Author(s):  
Pavan Kumar Konnepati ◽  
Pradip Majumdar
Keyword(s):  
Fuel Cell ◽  
Polymer Electrolyte ◽  
Current Density ◽  
Gas Flow ◽  
Polymer Electrolyte Membrane ◽  
Pem Fuel Cell ◽  
Bipolar Plate ◽  
Gas Diffusion ◽  
Limiting Current ◽  
Electrolyte Membrane

Fuel cells convert chemical energy of fuels into electricity directly. Their higher efficiency and low emissions made them prime candidates for next generation power requirements. The Polymer Electrolyte Membrane (PEM) fuel cell has gained attention of both transportation and stationary power generation industries. In this study a three-dimensional computational model for the simulation of Polymer Electrolyte Membrane (PEM) fuel cell unit cell is developed to understand the complex internal mechanisms, and evaluate the effects of bipolar plate designs on the cell performance. The model includes combined heat and mass transfer processes due to convection and diffusion in the gas flow channels of bi-polar plates as well in the gas diffusion layers of the electrodes, and associated electrochemical reactions in a tri-layer PEM fuel cell. Simulation is carried out with straight parallel channels for operating current density in the range from 0.5–1.5 A/cm2 showed significant insight details of PEM fuel cell in terms of distribution of reactant gases, and heat and water transport across the cell. A significantly high variation in gas concentration across the electrode–membrane interfaces and along the channel length is noticed, requiring higher stoichiometric ratios to increase the limiting current density.

CFD Simulation of Flow Through the Reconstructed Microstructure of Fibrous Gas Diffusion Layer in a Polymer Electrolyte Membrane Fuel Cell

2018 ◽  
Vol 13 (1) ◽  
Author(s):  
Venkata Suresh Patnaikuni ◽  
Sreenivas Jayanti
Keyword(s):  
Fuel Cell ◽  
Polymer Electrolyte ◽  
Diffusion Layer ◽  
Polymer Electrolyte Membrane ◽  
Effective Diffusion ◽  
Gas Diffusion Layer ◽  
Pem Fuel Cell ◽  
Pem Fuel Cells ◽  
Gas Diffusion ◽  
Electrolyte Membrane

AbstractThe gas diffusion layer (GDL) is one of the key components in a polymer electrolyte membrane (PEM) fuel cell. Generally it is a carbon-based fibrous medium that allows for the transport of electrons through the fibers and distributes the reactants through the void space to the catalyst layer in a PEM fuel cell. In the present work, a microstructure study of reactant transport is carried out by reconstructing the typical fibrous microstructure of the GDL and investigating the transport characteristics of the porous medium using computational fluid dynamics (CFD) simulations. The results confirm the applicability of Darcy’s law formulation for permeability determination and Bruggemann correction for calculation of effective diffusivity for typical conditions encountered in PEM fuel cells. Macroscopic material properties such as through-plane and in-plane permeabilities and effective diffusion coefficient are determined and compared against experimental values reported in the literature.

Synchrotron X-Ray Investigation of Membrane Water Distribution in Polymer Electrolyte Membrane Fuel Cell Applications

2017 ◽  
Author(s):  
Rupak Banerjee ◽  
Chuzhang Han ◽  
Nan Ge ◽  
Aimy Bazylak
Keyword(s):  
Fuel Cell ◽  
Polymer Electrolyte ◽  
Diffusion Layer ◽  
Current Density ◽  
Water Distribution ◽  
Polymer Electrolyte Membrane ◽  
Gas Diffusion ◽  
Cell Performance ◽  
X Ray ◽  
Electrolyte Membrane

Water management is a critical component of extracting optimum performance and efficiency from polymer electrolyte membrane (PEM) fuel cells. During fuel cell operation, a balance needs to be maintained between excess water blocking the reactant pathways through the gas diffusion layer, and the requirement for membrane hydration. The ionic conductivity through the membrane depends strongly on the hydration of the membrane. The reactant gases in a PEM fuel cell are supplied through a humidification system to maintain appropriate levels of hydration in the membrane. The removal of the anode humidifier would significantly reduce the balance of plant costs and reduce the volume required for the fuel cell in an automotive setting. However, removing the anode humidification system could have adverse effects on membrane hydration and on fuel cell performance. In this study, the anode humidification was varied and the cell performance and the membrane resistance were monitored. Synchrotron X-ray radiography was conducted simultaneously to visualize the water distribution in the membrane, the gas diffusion layer, and the associated interfaces. It was observed that the anode humidification had a strong impact on the performance of the fuel cell, with the dry condition leading to voltage instability at a current density below 1.0 A/cm2. The membrane water content was observed to decrease with increases in operating current density.

Graduated Flow Resistance Through a GDL in a Novel PEM Stack

2009 ◽  
Author(s):  
Terry B. Caston ◽  
Kanthi L. Bhamidipati ◽  
Haley Carney ◽  
Tequila A. L. Harris
Keyword(s):  
Fuel Cell ◽  
Polymer Electrolyte Membrane ◽  
Catalyst Layer ◽  
Current Density Distribution ◽  
Pem Fuel Cell ◽  
Bipolar Plate ◽  
Gas Diffusion ◽  
Carbon Paper ◽  
Carbon Cloth ◽  
Electrolyte Membrane

The goal of this study is to design a gas diffusion layer (GDL) for a polymer electrolyte membrane (PEM) fuel cell with a graduated permeability, and therefore a graduated resistance to flow throughout the GDL. It has been shown that using conventional materials the GDL exhibits a higher resistance in the through-plane direction due to the orientation of the small carbon fibers that make up the carbon paper or carbon cloth. In this study, a GDL is designed for an unconventional PEM fuel cell stack, where the reactant gases are supplied through the side of the GDL rather than through flow field channels, which are machined into a bipolar plate. The effects of changing in-plane permeability, through-plane permeability, and thickness of the GDL on the expected current density distribution at the catalyst layer are studied. Three different thicknesses are investigated, and it is found that as GDL thickness increases, more uniform reactant distribution over the face of the GDL is obtained. Results also show that it is necessary to design a GDL with a much higher in-plane resistance than through-plane resistance for the unconventional PEM stack studied.

scholarly journals A Competitive Design and Material Consideration for Fabrication of Polymer Electrolyte Membrane Fuel Cell Bipolar Plates

Designs ◽  
2019 ◽  
Vol 3 (1) ◽  
pp. 13
Author(s):  
Noor Ul Hassan ◽  
Bahadir Tunaboylu ◽  
Ali Soydan
Keyword(s):  
Fuel Cell ◽  
Polymer Electrolyte ◽  
Mass Production ◽  
Polymer Electrolyte Membrane ◽  
Expanded Graphite ◽  
Pem Fuel Cell ◽  
Bipolar Plate ◽  
Small Scale ◽  
Bipolar Plates ◽  
Electrolyte Membrane

The bipolar plate is one of the most significant components of a polymer electrolyte membrane (PEM) fuel cell, and contributes substantially to the cost structure and the weight of the stacks. A number of graphite polymer composites with different fabrication techniques have been reported in the literature. Graphite composites show excellent electromechanical properties and chemical stability in acidic environments. Compression and injection molding are the most common manufacturing methods being used for mass production. In this study, a competitive bipolar plate design and fabrication technique is adopted in order to develop a low-cost and light-weight expanded graphite (EG) polymer composite bipolar plate for an air-breathing PEM fuel cell. Cutting molds are designed to cut fuel flow channels on thin expanded graphite (EG) sheets (0.6 mm thickness). Three separate sheets, with the flow channel textures removed, are glued to each other by a commercial conductive epoxy to build a single bipolar plate. The final product has a density of 1.79 g/cm3. A bipolar plate with a 20 cm2 active area weighs only 11.38 g. The manufacturing cost is estimated to be 7.77 $/kWe, and a total manufacturing time of 2 minutes/plate is achieved with lab-scale fabrication. A flexural strength value of 29 MPa is obtained with the three-point bending method. A total resistance of 22.3 milliohms.cm2 is measured for the three-layer bipolar plate. We presume that the suggested design and fabrication process can be a competitive alternate for the small-scale, as well as mass production of bipolar plates.

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