scholarly journals Ultrathin Electrolyte Membranes with PFSA-Vinylon Intermediate Layers for PEM Fuel Cells

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1730
Author(s):  
Jedeok KIM ◽  
Kazuya Yamasaki ◽  
Hitoshi Ishimoto ◽  
Yusuke Takata
Keyword(s):  
Fuel Cells ◽  
Polyvinyl Alcohol ◽  
High Current Density ◽  
Pem Fuel Cells ◽  
High Humidity ◽  
High Current ◽  
Intermediate Layers ◽  
Current Voltage ◽  
Electrolyte Membranes ◽  
Reinforcing Material

We prepared ultrathin PFSA/PFSA-vinylon/PFSA laminated electrolyte membranes (thickness = 10 μm) for fuel cells without using a reinforcing material. Nafion and Aquivion solutions were used as PFSA polymers. Vinylon was synthesized by formalizing polyvinyl alcohol. From the current-voltage measurements using ultrathin PFSA/PFSA-vinylon/PFSA membranes; the cell resistances are significantly lower than that using a 50 μm Nafion membrane. A high current density was obtained under both low- and high-humidity conditions. Ultrathin PFSA/PFSA-vinylon/PFSA laminated membranes will help to further improve the performance of PEMFCs.

Computer Models of Pem Fuel Cells for the Study of Transient Modes in Electrical Power Supply Complexes

2021 ◽  
Vol 64 (3) ◽  
pp. 60-67
Author(s):  
Ivan Vasyukov ◽  
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Dynamic Response ◽  
Gradient Descent ◽  
Eddy Currents ◽  
Least Squares Method ◽  
Electrical Power ◽  
Computer Models ◽  
Pem Fuel Cells ◽  
Current Voltage

Static and dynamic computer models of fuel cells are considered. A static model is determined that most ac-curately reproduces the current-voltage characteristic of a real fuel cell. A method for tuning it according to the experimental I - V characteristic by the least squares method is proposed. A method for its adjustment ac-cording to the experimental I - V characteristic by the method of gradient descent is proposed. A modified elec-trical equivalent circuit of a fuel cell has been developed, which simulates its dynamic response, taking into ac-count the damping effect of eddy currents during operation of a stack of fuel cells on a pulse voltage converter. A method is proposed for determining the parameters of the model from the experimental oscillograms of the current and voltage of the stack. A universal model of a stack of fuel cells in LTspice has been developed, which makes it possible to simulate a dynamic response and, if necessary, simulate a real static I – V characteristic of the stack.

Preparation and Characterization of CMC-PVA/PVA-SA-MePc (COOH)8/CS-PVA Bipolar Membrane Using Electrospinning Technique

2013 ◽  
Vol 774-776 ◽  
pp. 795-798
Author(s):  
Ting Jin Zhou ◽  
Min Lu ◽  
Ri Yao Chen
Keyword(s):  
Polyvinyl Alcohol ◽  
Water Splitting ◽  
Current Density ◽  
Voltage Drop ◽  
High Current Density ◽  
High Current ◽  
Bipolar Membrane ◽  
Electrospinning Technique ◽  
Exchange Layer

Carboxymethyl cellulose (CMC)-polyvinyl alcohol (PVA) and chitosan (CS)-polyvinyl alcohol were cross-linked by Fe3+and glutaraldehyde respectively to prepare cation exchange layer and anion exchange layer, and polyvinyl alcohol-sodium alginate (SA)-metal octocarboxyphthalocyanine (MePc (COOH)8, a kind of water splitting catalyst, here, Me stands for Fe3+or Co2+) nanofibers were prepared by electrospinning technique and introduced into the interlayer to obtain the CMC-PVA/PVA-SA-MePc (COOH)8/CS-PVA bipolar membrane (BPM). The experimental results showed that compared with the BPM without the PVA-SA-MePc (COOH)8interlayer, the water splitting efficiency at the interlayer of the CMC-PVA/PVA-SA-MePc (COOH)8/ CS-PVA BPM was obviously increased, and its membrane impedance decreased. When the concentration of FePc (COOH)8in the PVA-SA-FePc (COOH)8nanofibers was 3.0%, the trans-membrane voltage drop (IRdrop) of the CMC-PVA/PVA-SA-FePc (COOH)8/CS-PVA BPM was as low as 0.6V at a high current density of 90 mA/cm2.

Separate Measurement of Current Density Under the Channel and the Shoulder in PEM Fuel Cells

2007 ◽  
Author(s):  
Lin Wang ◽  
Hongtan Liu
Keyword(s):  
Fuel Cells ◽  
Diffusion Layer ◽  
Current Density ◽  
Electrical Resistance ◽  
High Current Density ◽  
Gas Diffusion Layer ◽  
Pem Fuel Cells ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Experimental Results

In a proton exchange membrane (PEM) fuel cell current density under the shoulder can be very different from that under the gas channel and the knowledge of where the current density is higher is critical in flow field designs in order to optimize cell performance. Yet, up to date this issue has not been resolved. In this study, a novel yet simple approach was adopted to directly measure the current densities under the channel and the shoulder in PEM fuel cells separately. In this approach, the cathode catalyst layer was so designed that either the area under the shoulder or the area under the channel was loaded with catalyst. Such a design guaranteed the currents generated under the shoulder and the channel could be measured separately. Experimental results showed that the current density produced under the channel was lower than that under the shoulder except in the high current density region. To determine whether the lateral electrical resistance of the gas diffusion layer (GDL) was the causes for lower current density under the channel, an additional set of experiments were conducted. In this set of experiments, a silver mesh was added on the top of the gas diffusion layer (GDL) and the experimental results showed that GDL lateral electrical resistance was not the cause and it had a negligible effect on lateral current density distribution.

scholarly journals Current-voltage curve of a bipolar membrane at high current density

Desalination ◽  
1996 ◽  
Vol 104 (1-2) ◽  
pp. 13-18 ◽  
Author(s):  
T. Aritomi ◽  
Th. van den Boomgaard ◽  
H. Strathmann
Keyword(s):  
Current Density ◽  
High Current Density ◽  
High Current ◽  
Bipolar Membrane ◽  
Voltage Curve ◽  
Current Voltage ◽  
Current Voltage Curve

The Nature of Flooding and Drying in Polymer Electrolyte Fuel Cells

2005 ◽  
Author(s):  
P. A. Chuang ◽  
A. Turhan ◽  
A. K. Heller ◽  
J. S. Brenizer ◽  
T. A. Trabold ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Current Density ◽  
Liquid Water ◽  
High Current Density ◽  
Liquid Water Content ◽  
Small Mass ◽  
Neutron Imaging ◽  
Small Range ◽  
High Current ◽  
Voltage Loss

Two different 50 cm2 fuel cells operated at high current density (1.3A/cm2–1.5A/cm2) were visualized using neutron imaging, and the liquid water content in the flow channels and diffusion media under the lands and channels was calculated and compared. At high current density with fully humidified inlet flow, a direct comparison between flooded and non-flooded conditions was achieved by increasing the fuel cell temperature over a small range, until voltage loss from flooding was alleviated. Results indicate that a surprisingly small mass of liquid water is responsible for a significant voltage loss. The deleterious effects of flooding are therefore more easily explained with a locally segregated flooded pore model, rather than a homogeneously flooded pore and blockage phenomenon. Anode dryout was similarly observed and quantified, and results indicate that an exceedingly small mass of water is responsible for significant voltage loss, which is consistent with expectations. The results presented help to form a more complete vision of the flooding loss and anode dryout phenomena in PEFCs.

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