A Comparative 1D Analysis of PEM, SO and DB Fuel Cells

Author(s):  
Isaac Perez-Raya ◽  
Michael W. Ellis ◽  
Abel Hernandez-Guerrero ◽  
Francisco Elizalde-Blancas ◽  
Carlos U. Gonzalez-Valle ◽  
...  

Although fuel cells represent an attractive alternative for electricity generation, different technical problems, such as the hydrogen storage, have not been solved, as yet. Nowadays direct sodium borohydride fuel cells are considered as a promising technology since NaBH4 (fuel) is a stable, nonflammable and nontoxic liquid solution. In the present study a one-dimensional numerical study of a proton exchange membrane, a solid oxide, and a direct sodium borohydride fuel cell is performed. The objective of this work is to compare qualitatively the fuel cell performance between these technologies. For proton exchange membrane and solid oxide fuel cells there are already established useful models and correlations widely known, and used, to predict the current density and the power generated. Direct Borohydride fuel cells, on the other hand, are still in their early developments; in the present paper DBFCs are analyzed using a novel model. This proposed model for DBFCs includes the prediction of the NaBH4 oxidation in the anode side, the H2O2 reduction in the cathode side and the effect of the solution concentration and temperature on the membrane. It is noteworthy mentioning that this last effect has not been integrated in any of the established models in the current technical literature.

Author(s):  
Saher Al Shakhshir ◽  
Xin Gao ◽  
Torsten Berning

Abstract In a previous numerical study on heat and mass transfer in air-cooled proton exchange membrane fuel cells, it was found that the performance is limited by heat transfer to the cathode side air stream that serves as a coolant, and it was proposed to place a turbulence grid before the cathode inlet in order to induce a mixing effect to the air and thereby improve the heat transfer and ultimately increase the limiting current and maximum power density. The current work summarizes experiments with different turbulence grids which varied in terms of their pore size, grid thickness, rib width, angle of the pores, and the distance between the grid and the cathode inlet. For all grids tested in this study, the limiting current density of a Ballard Mark 1020 ACS stack was increased by 20%. The single most important parameter was the distance between the turbulence grid and the cathode inlet, and it should be within 5 mm. For the best grid tested, the fuel cell stack voltage and thus the efficiency were increased by up to 20%. The power density was increased by more than 30% and further improvements are believed to be possible.


Author(s):  
Georgiy Diloyan ◽  
Parsaoran Hutapea

One of the factors that affect the performance of proton exchange membrane fuel cells (PEMFC) is the loss of electrochemically active surface area of the Platinum (Pt) based electrocatalyst due to platinum dissolution and sintering. The intent of the current research is to understand the effect of mechanical vibrations on the Pt particles dissolution and overall PEMFC performance. This study is of great importance for the automotive application of fuel cells, since they operate under a vibrating environment. Carbon supported platinum plays an important role as an electrocatalyst in PEMFC. Pt particles, typically a few nanometers in size, are distributed on both cathode and anode sides. Pt particle dissolution and sintering is accelerated by a number of factors, one of which is potential cycling during fuel cell operation. To study the effect of mechanical vibrations on Pt dissolution and sintering, an electrocatalyst (from cathode side) was analyzed by SEM/EDS (Energy Dispersive Spectroscopy). The performance, dissolution and sintering of the Pt particles of 25 cm2 electrocatalyst coated membrane were studied during a series of tests. The experiment was conducted by running three accelerated tests. Each test duration was 300 hours, with different parameters of oscillations: one test without vibrations and remaining two tests under vibrations with frequencies of 20 Hz and 50 Hz (5g of magnitude) respectively. For each of the three tests a pristine membrane was used. The catalyst of each membrane was analyzed by ESEM/EDS in pristine state and in degraded state (after 300 hours of accelerated test). In order to specify the same area of observation on a catalyst before and after accelerated test, a relocation technique was used.


2019 ◽  
Vol 10 (1) ◽  
pp. 4853-4863

Hydrogen is an important energy carrier and a strong candidate for energy storage. It will be a useful tool for storing intermittent energy sources such as sun. Hydrogen is a versatile energy carrier that can be used to power nearly every end-use energy need. By this work, modeling and controlling of ion transport rate efficiency in proton exchange membrane (PEMFC), alkaline (AFC), direct methanol (DMFC), phosphoric acid (PAFC), direct forming acid (DFAFC), direct carbon fuel cell (DCFC) and molten carbonate fuel cells (MCFC) have been investigated and compared together. Thermodynamic equations have been investigated for those fuel cells in viewpoint of voltage output data. Effects of operating data including temperature (T), pressure (P), proton exchange membrane water content (λ), and proton exchange membrane thickness (d_mem) on the optimal performance of the irreversible fuel cells have been studied. Performance of fuel cells was analyzed via simulating polarization and power curves for a fuel cell operating at various conditions with current densities. SOFC (Solid oxide fuel cell) is usually combined with a dense electrolyte sandwiched via porous cathode and anode and SORFC (Solid oxide regenerative fuel cell) is a subgroup of RFC with solid oxide regenerative fuel cell. SORFC operates at high temperature with high efficiency and it is a suitable system for high temperature electrolysis.


2019 ◽  
Author(s):  
Valentina Guccini ◽  
Annika Carlson ◽  
Shun Yu ◽  
Göran Lindbergh ◽  
Rakel Wreland Lindström ◽  
...  

The performance of thin carboxylated cellulose nanofiber-based (CNF) membranes as proton exchange membranes in fuel cells has been measured in-situ as a function of CNF surface charge density (600 and 1550 µmol g<sup>-1</sup>), counterion (H<sup>+</sup>or Na<sup>+</sup>), membrane thickness and fuel cell relative humidity (RH 55 to 95 %). The structural evolution of the membranes as a function of RH as measured by Small Angle X-ray scattering shows that water channels are formed only above 75 % RH. The amount of absorbed water was shown to depend on the membrane surface charge and counter ions (Na<sup>+</sup>or H<sup>+</sup>). The high affinity of CNF for water and the high aspect ratio of the nanofibers, together with a well-defined and homogenous membrane structure, ensures a proton conductivity exceeding 1 mS cm<sup>-1</sup>at 30 °C between 65 and 95 % RH. This is two orders of magnitude larger than previously reported values for cellulose materials and only one order of magnitude lower than Nafion 212. Moreover, the CNF membranes are characterized by a lower hydrogen crossover than Nafion, despite being ≈ 30 % thinner. Thanks to their environmental compatibility and promising fuel cell performance the CNF membranes should be considered for new generation proton exchange membrane fuel cells.<br>


2017 ◽  
Vol 10 (1) ◽  
pp. 96-105 ◽  
Author(s):  
Mohammed Jourdani ◽  
Hamid Mounir ◽  
Abdellatif El Marjani

Background: During last few years, the proton exchange membrane fuel cells (PEMFCs) underwent a huge development. Method: The different contributions to the design, the material of all components and the efficiencies are analyzed. Result: Many technical advances are introduced to increase the PEMFC fuel cell efficiency and lifetime for transportation, stationary and portable utilization. Conclusion: By the last years, the total cost of this system is decreasing. However, the remaining challenges that need to be overcome mean that it will be several years before full commercialization can take place.This paper gives an overview of the recent advancements in the development of Proton Exchange Membrane Fuel cells and remaining challenges of PEMFC.


ACS Omega ◽  
2021 ◽  
Vol 6 (34) ◽  
pp. 21892-21899
Author(s):  
Yixiang Wang ◽  
Lei Wang ◽  
Xianhang Ji ◽  
Yulu Zhou ◽  
Mingge Wu

Author(s):  
Frano Barbir ◽  
Haluk Gorgun ◽  
Xinting Wang

Pressure drop on the cathode side of a PEM (Proton Exchange Membrane) fuel cell stack has been studied and used as a diagnostic tool. Since the Reynolds number at the beginning of the flow field channel was <250, the flow through the channel is laminar, and the relationship between the pressure drop and the flow rate is linear. Some departure from linearity was observed when water was either introduced in the stack or produced inside the stack in the electrochemical reaction. By monitoring the pressure drop in conjunction with the cell resistance in an operational fuel cell stack, it was possible to diagnose either flooding or drying conditions inside the stack.


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