scholarly journals Impedance Spectroscopy Measurements of Ionomer Film Oxygen Transport Resistivity in Operating Low-Pt PEM Fuel Cell

Membranes ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 985
Author(s):  
Tatyana V. Reshetenko ◽  
Andrei Kulikovsky
Keyword(s):  
Fuel Cells ◽  
Proton Exchange Membrane ◽  
Cell System ◽  
Proton Exchange ◽  
Impedance Spectra ◽  
O2 Transport ◽  
Operating Current ◽  
Current Densities ◽  
Exchange Membrane ◽  
Segmented Cell

The work presents a model for local impedance of low-Pt proton exchange membrane fuel cells (PEMFCs), including cathode pore size distribution and O2 transport along pores and through a thin ionomer film covering Pt/C agglomerates. The model was applied to fit the local impedance spectra of low-Pt fuel cells operated at current densities from 100 to 800 mA cm−2 and recorded by a segmented cell system. Assuming an ionomer film thickness of 10 nm, the fitting returned the product of the dimensionless Henry’s constant of oxygen dissolution in ionomer KH by the oxygen diffusivity DN in the ionomer (KHDN). This parameter allowed us to determine the fundamental O2 transport resistivity RN through the ionomer film in the working electrode under conditions relevant to the realistic operation of PEMFCs. The results show that variation of the operating current density does not affect RN, which remains nearly constant at ≃0.4 s cm−1.

scholarly journals Measurements Based Analysis of the Proton Exchange Membrane Fuel Cell Operation in Transient State and Power of Own Needs

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 498
Author(s):  
Andrzej Wilk ◽  
Daniel Węcel
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Transient State ◽  
Experimental Tests ◽  
Cell System ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Variable Load ◽  
Exchange Membrane

Currently, fuel cells are increasingly used in industrial installations, means of transport, and household applications as a source of electricity and heat. The paper presents the results of experimental tests of a Proton Exchange Membrane Fuel Cell (PEMFC) at variable load, which characterizes the cell’s operation in real installations. A detailed analysis of the power needed for operation fuel cell auxiliary devices (own needs power) was carried out. An analysis of net and gross efficiency was carried out in various operating conditions of the device. The measurements made show changes in the performance of the fuel cell during step changing or smooth changing of an electric load. Load was carried out as a change in the current or a change in the resistance of the receiver. The analysis covered the times of reaching steady states and the efficiency of the fuel cell system taking into account auxiliary devices. In the final part of the article, an analysis was made of the influence of the fuel cell duration of use on obtained parameters. The analysis of the measurement results will allow determination of the possibility of using fuel cells in installations with a rapidly changing load profile and indicate possible solutions to improve the performance of the installation.

Exploration of significant influences of the operating conditions on the local O2 transport in proton exchange membrane fuel cells (PEMFCs)

2017 ◽  
Vol 19 (38) ◽  
pp. 26221-26229 ◽  
Author(s):  
Shuiyun Shen ◽  
Xiaojing Cheng ◽  
Chao Wang ◽  
Xiaohui Yan ◽  
Changchun Ke ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Mole Fraction ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Operating Conditions ◽  
O2 Transport ◽  
Exchange Membrane

Contrary to established rules, the local O2 transport resistance is aggravated along with the increase in dry mole fraction O2.

Three-dimensional numerical simulation of full-scale proton exchange membrane fuel cells at high current densities

2021 ◽  
Vol 488 ◽  
pp. 229412
Author(s):  
Takayuki Tsukamoto ◽  
Tsutomu Aoki ◽  
Hiroyuki Kanesaka ◽  
Tadahiko Taniguchi ◽  
Tsutomu Takayama ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Fuel Cells ◽  
Proton Exchange Membrane ◽  
Three Dimensional ◽  
Full Scale ◽  
Proton Exchange ◽  
High Current ◽  
Current Densities ◽  
Exchange Membrane

An Analysis of Two-Phase Flow Pressure Drop in Operating Proton Exchange Membrane Fuel Cell Channels With the Lockhart-Martinelli Approach

2014 ◽  
Author(s):  
Ryan Anderson ◽  
Lifeng Zhang ◽  
David P. Wilkinson
Keyword(s):  
Fuel Cells ◽  
Pressure Drop ◽  
Proton Exchange Membrane ◽  
Two Phase Flow ◽  
Proton Exchange ◽  
Phase Flow ◽  
Two Phase ◽  
Current Densities ◽  
Flow Pressure ◽  
Exchange Membrane

Proton exchange membrane fuel cells (PEMFCs) are considered one of the most promising alternatives for the automotive industry owing to their high energy efficiency, zero emission at the vehicle use stage, and low temperature operation. Water as a byproduct plays a complex role in fuel cell operation. In particular, the inevitable occurrence of liquid water leads to gas-liquid two-phase flows in various components of PEMFCs including flow channels of which diameters range from micrometers to millimeters. In conventional minichannels and microchannels, the Lockhart-Martinelli (LM) approach has been employed to predict the two-phase pressure drop of gas-liquid systems. This approach has previously been updated by our group to more accurately reflect the introduction of liquid water into the flow channels of a PEMFC i.e. from a porous media perpendicular to the gas flow. Importantly, the LM method normalizes the data independent of the flow field design and operating conditions like temperature, pressure, and relative humidity. This paper analyzes the increasing amount of experimental data on two-phase flow pressure drops/two-phase flow multipliers in the literature with these approaches. The focus is the cathode side (therefore an air/water system), and data is collected from multiple research groups using active fuel cells (electrochemically produced water). The traditional LM approach greatly under-predicts the two-phase pressure drop at low current densities. However, the analysis is applied over a range of current densities, and it better predicts results at higher current densities (>600 mA cm−2). Literature correlations for the Chisholm parameter C, a flow regime dependent parameter in the LM equation, have been proposed for non-active (external water injection) fuel cells but do not match the results from operating fuel cells. C is shown here to vary with current density, flow stoichiometry (gas velocity), gas diffusion layer, and slightly with relative humidity.

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