Experimental Evaluation of Planar SOFC Single Unit Cell With Crofer22APU Plate Assembly

Author(s):  
P. Leone ◽  
A. Lanzini ◽  
B. Delhomme ◽  
G. A. Ortigoza-Villalba ◽  
M. Santarelli ◽  
...  

This paper describes an experimental analysis of a planar solid oxide fuel cell (SOFC) single unit cell with Crofer22APU plate assembly. The work reports the electrical behavior of such a system by outlining the time-evolution of contact resistances between the air electrode and the stainless steel plate. Moreover, the stability and effectiveness of a glass-ceramic sealant used to join Crofer22APU interconnector to an anode supported cell is also discussed. The time-evolution of the open circuit voltage was investigated with respect to the eventual sealant degradation or chromium poisoning issues by the metallic interconnector; a rapid voltage degradation at open circuit voltage was measured after 150 h. Chromium poisoning was found to degrade the fuel cell performance, whereas the sealant was chemically and physically stable, as shown by a post-mortem analysis on the cell components.

2013 ◽  
Vol 566 ◽  
pp. 137-140 ◽  
Author(s):  
Hiroki Ichiboshi ◽  
Kenichi Myoujin ◽  
Takayuki Kodera ◽  
Takashi Ogihara

Ce0.8Sm0.2O1.9 (Samaria-doped ceria: SDC) precursors were synthesized by carbon-assisted spray pyrolysis. SDC thin films were prepared by electrophoretic deposition using the SDC precursor particles. The as-prepared SDC thin films were sintered at 1600 °C for 10 h. Uniform films with a thickness of approximately 20 μm were obtained. A fuel cell using the prepared thin films showed a maximum power density of 60.6 mW/cm2 and an open circuit voltage (OCV) of 0.63 V at 700 °C.


2013 ◽  
Vol 10 (5) ◽  
Author(s):  
K. Scott ◽  
S. Pilditch ◽  
M. Mamlouk

A steady-state, isothermal, one-dimensional model of a direct methanol proton exchange membrane fuel cell (PEMFC), with a polybenzimidazole (PBI) membrane, was developed. The electrode kinetics were represented by the Butler–Volmer equation, mass transport was described by the multicomponent Stefan–Maxwell equations and Darcy's law, and the ionic and electronic resistances described by Ohm's law. The model incorporated the effects of temperature and pressure on the open circuit potential, the exchange current density, and diffusion coefficients, together with the effect of water transport across the membrane on the conductivity of the PBI membrane. The influence of methanol crossover on the cathode polarization is included in the model. The polarization curves predicted by the model were validated against experimental data for a direct methanol fuel cell (DMFC) operating in the temperature range of 125–175 °C. There was good agreement between experimental and model data for the effect of temperature and oxygen/air pressure on cell performance. The fuel cell performance was relatively poor, at only 16 mW cm−2 peak power density using low concentrations of methanol in the vapor phase.


2018 ◽  
Vol 57 (4S) ◽  
pp. 04FM04 ◽  
Author(s):  
Shigeki Arata ◽  
Kenya Hayashi ◽  
Yuya Nishio ◽  
Atsuki Kobayashi ◽  
Kazuo Nakazato ◽  
...  

2016 ◽  
Vol 56 (1S) ◽  
pp. 01AH04 ◽  
Author(s):  
Kiichi Niitsu ◽  
Takashi Ando ◽  
Atsuki Kobayashi ◽  
Kazuo Nakazato

Author(s):  
A. Chukwujekwu Okafor ◽  
Hector-Martins Mogbo

In this paper, the effects of gas flow rates, and catalyst loading on polymer electrolyte membrane fuel cell (PEMFC) performance was investigated using a 50cm2 active area fuel cell fixture with serpentine flow field channels machined into poco graphite blocks. Membrane Electrode Assemblies (MEAs) with catalyst and gas flow rates at two levels each (0.5mg/cm2, 1mg/cm2; 0.3L/min, 0.5L/min respectively) were tested at 60°C without humidification. The cell performance was analyzed by taking AC Impedance, TAFEL plot, open circuit voltage, and area specific resistance measurements. It was observed that MEAs with lower gas flow rate had lesser cell resistance compared to MEAs with a higher gas flow rate. TAFEL plot shows the highest exchange current density value of −2.05 mAcm2 for MEA with 0.5mg/cm2 catalyst loading operated at reactant gas flow rate of 0.3L/min signifying it had the least activation loss and fastest reaction rate. Open circuit voltage curve shows a higher output voltage and lesser voltage decay rate for MEAs tested at higher gas flow rates.


2013 ◽  
Vol 346 ◽  
pp. 23-28
Author(s):  
Jarosław Milewski ◽  
Wojciech Bujalski ◽  
Marcin Wołowicz ◽  
Kamil Futyma ◽  
Jan Kucowski ◽  
...  

This work considers electronic conductance in a molten carbonate fuel cell and consequences of its existence. The voltage characteristics of cells show differences between a theoretical maximum circuit voltage and open circuit voltage (OCV). A relationship is assumed between the OCV value and electronic conductance. Based on experimental measurements an appropriate mathematical model was created. The model is used to calculate the temperature dependence of electronic conductance for the most popular types of electrolyte: Li2CO3/K2CO3. The results obtained point to the possible existence of a very close relationship between electronic conductance and open circuit voltage. This relationship enables OCV to be calculated when electronic conductance is known. Appropriate formulae can be determined. Temperature is one of the factors affecting electronic conductance. Other influencing factors do exist, but their impact on OCV is not well known. This article mentions some of them.


Author(s):  
Pinchas Schechner ◽  
Eugenia Bubis ◽  
Hana Faiger ◽  
Eyal Zussman ◽  
Ehud Kroll

This work adds more experimental evidence regarding the feasibility of using glucose to fuel fuel-cells with anodes that have a high area-to-volume ratio. Electrospinning was used to fabricate sub-micrometer size fibrous electrocatalytic anode membranes for the oxidation of glucose in an alkaline fuel cell (AFC). The fibers of the membranes were made of polyacrylonitrile (PAN) and coated with silver by electroless plating. The anodes were tested while installed in a membranless fuel cell. The results presented include the open circuit voltage, OCV, the polarization curve, the power density as a function of the current density, and the peak power density, PPD. The measurements were performed with constant concentrations of glucose, 0.8 M, and KOH electrolyte solution, 1M. The performance of the anodes was found to improve as the diameter of the silver-plated fibers decreased. The highest PPD of 0.28 mW/cm2 was obtained with an anode made of plated fibers having a mean fiber diameter of 130 nanometers. We conclude from the results that saccharides in general, and glucose in particular, can serve as fuels for fuel cells, and that silver-plated polymeric electrospun electrodes have advantages due to their large surface area.


Nano Energy ◽  
2016 ◽  
Vol 27 ◽  
pp. 619-626 ◽  
Author(s):  
Haiyang Zou ◽  
Jun Chen ◽  
Yunnan Fang ◽  
Jilai Ding ◽  
Wenbo Peng ◽  
...  

Author(s):  
Anthony C. Okafor ◽  
Hector-Martins C. Mogbo

In this paper, the effects of gas flow rates and catalyst loading on polymer electrolyte membrane fuel cell (PEMFC) performance was investigated using a 50 cm2active area fuel cell fixture with serpentine flow field channels machined into poco graphite blocks. Membrane electrode assemblies (MEAs) with catalyst and gas flow rates at two levels each (0.5 mg/cm2, 1 mg/cm2; 0.3 l/min, 0.5 l/min, respectively) were tested at 60 °C without humidification. The cell performance was analyzed by taking ac impedance, Tafel plot, open circuit voltage, and area specific resistance measurements. It was observed that MEAs with lower gas flow rate had lesser cell resistance compared to MEAs with a higher gas flow rate. Tafel plot shows the highest exchange current density value of 10−2.05 mA cm2 for MEA with 0.5 mg/cm2 catalyst loading tested at reactant gas flow rate of 0.3 l/min signifying it had the least activation loss and fastest reaction rate. Open circuit voltage-time curve shows a higher output voltage and lesser voltage decay rate for MEAs tested at higher gas flow rates.


2019 ◽  
Vol 8 (4) ◽  
pp. 402
Author(s):  
Doudou N. Luta ◽  
Atanda K. Raji

The concept of power tracking was at first applied to renewable power systems and especially those based on solar and wind to extract as much power as possible from them. Both types of power systems operate on the principle of converting either solar or wind into electricity. Thus, their output power is direct dependent on the solar radiation for solar power systems and on the wind speed for wind generators. To maintain efficient system operations, the output power of these power systems is optimized through maximum power tracking techniques. In the similar vein, fuel cell stacks display nonlinear output powers resulting from internal limitations and operating parameters such as tem-perature, hydrogen and oxygen partial pressures and humidity levels, etc., leading to a reduced system performance. It is critical to extract as much power as possible from the stack, thus, to prevent also an excessive fuel use. To ensure that, the power converter interfaced to the stack must be able to self-adjust its parameters continuously, hence modifying its voltage and current depending upon the maximum power point position. Diverse techniques are utilized to extract maximum power from the fuel-cell stack.  In this paper, a fractional open circuit voltage and fuzzy rule based maximum power tracking techniques are considered and compared. The proposed system consists of a 50 kW Proton Exchange Membrane fuel cell interfaced to a DC-to-DC boost converter. The converter is designed to deliver 1.2 kV from 625 V input voltage. The simulation is carried out under Matlab/Simulink environment.  


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