Investigation of Transport Phenomena in Micro Flow Channels for Miniature Fuel Cells

Author(s):  
S. W. Cha ◽  
S. J. Lee ◽  
Y. I. Park ◽  
F. B. Prinz

This paper presents a study on the transport phenomena related to gas flow through fuel cell micro-channels, specifically the impact of dimensional scale on the order of 100 microns and below. Especially critical is the ability to experimentally verify model predictions, and this is made efficiently possible by the use of structural photopolymer (SU-8) to directly fabricate functional fuel cell micro-channels. The design and analysis components of this investigation apply 3-D multi-physics modeling to predict cell performance under micro-channel conditions. Interestingly, the model predicts that very small channels (specifically 100 microns and below) result in a significantly higher peak power density than larger counterparts. SU-8 micro-channels with different feature sizes have been integrated into fuel cell prototypes and tested for comparison against model predictions. The results not only demonstrate that the SU-8 channels with metal current collector show quite appreciable performance, but also provide experimental verification of the merits of channel miniaturization. As predicted, the performance in terms of peak power density increases as the feature size of the channel decreases, even though the pressure drop is higher in the more narrow channels. So it has been observed both theoretically and experimentally that cell performance shows an improving trend with micro-channels, and design optimization for miniature fuel cell provides a powerful method for increasing power density.

2012 ◽  
Vol 512-515 ◽  
pp. 1520-1524 ◽  
Author(s):  
Yu Zhao ◽  
Xiao Bin Wang ◽  
Peng Li ◽  
Yan Ping Sun

Electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), power density and anode potential are used to characterize the mediator microbial fuel cell at different methylene blue (MB) concentrations. At lower MB concentration between 9.98×10-3 mmol/L and 1.66×10-1 mmol/L, the increased power density is enabled by using high mediator concentrations. Higher peak power density of 159.6 mw/m2 is observed compared with the peak power density of 36.0 mw/m2. But MB at too high concentration is disadvantageous to the perform of MFC. At the MB concentration of 2.50×10-1 mmol/L, the peak power output is just 128.4 mw/m2, which is lower than 159.6 mw/m2 at MB concentration of 1.66×10-1 mmol/L.


2007 ◽  
Vol 60 (7) ◽  
pp. 528 ◽  
Author(s):  
Jason M. Tang ◽  
Kurt Jensen ◽  
Wenzhen Li ◽  
Mahesh Waje ◽  
Paul Larsen ◽  
...  

A simple and promising fuel-cell architecture is demonstrated using a carbon nanotube free-standing membrane (CNTFSM) made from Pt supported on purified single-walled carbon nanotubes (Pt/SWNT), which act as the catalyst layer in a hydrogen proton exchange membrane fuel cell without the need for Nafion in the catalyst layer. The CNTFSM made from Pt/SWNT at a loading of 0.082 mg Pt cm–2 exhibits higher performance with a peak power density of 0.675 W cm–2 in comparison with a commercially available E-TEK electrocatalyst made of Pt supported on XC-72 carbon black, which had a peak power density of 0.395 W cm–2 at a loading of 0.084 mg Pt cm–2 also without Nafion in the catalyst layer.


Chemija ◽  
2018 ◽  
Vol 29 (4) ◽  
Author(s):  
Aldona Balčiūnaitė ◽  
Zita Sukackienė ◽  
Loreta Tamašauskaitė-Tamašiūnaitė ◽  
Rimantas Vaitkus ◽  
Eugenijus Norkus

The electroless deposition and galvanic displacement methods were used for the fabrication of cobalt–boron (CoB) catalysts modified with small amounts of platinum crystallites in the range of 9.8 to 14.4 μgPt cm–2. The prepared catalysts were studied as the anode materials for direct borohydride–hydrogen peroxide (NaBH4/H2O2) fuel cells at temperatures of 25–55°C. Polarization curves have been recorded with the aim to evaluate the fuel cell performance using the prepared CoB and that modified with Pt crystallites as the anode catalysts. For all catalysts (pure CoB and PtCoB) investigated, the peak power density values increase consecutively with the increment in temperature from 25°C up to 55°C. The values from 86–146 mV cm–2 and 146–234 mV cm–2 were determined for pure CoB and PtCoB catalysts, respectively. The highest specific peak power density of 21.5 kWgPt–1 was achieved at 55°C temperature when the PtCoB catalyst with the Pt loading of 9.8 μgPtcm–2 was employed as the anode catalyst in the NaBH4/H2O2 single fuel cell.


Author(s):  
Suk Won Cha ◽  
Ryan O’Hayre ◽  
F. B. Prinz

The paper presents a study on the transport phenomena related to gas flow through fuel cell micro-channels, specifically the impact of dimensional scale on the order of 100 microns and below. The use of structural photopolymer (SU-8) enabled the direct fabrication of functional fuel cell micro-channels. Previous experimental observation has revealed that if flow channels are too small, they may reduce the performance of fuel due to flooding (Cha et al., 2003). For further investigation, AC Impedance technique has been employed to measure the mass transfer resistance. The result confirmed that in smaller channels, mass transportation resistance increases due to the flooding.


2020 ◽  
Vol 56 (42) ◽  
pp. 5669-5672
Author(s):  
Zhanna Tatus-Portnoy ◽  
Anna Kitayev ◽  
Thazhe Veettil Vineesh ◽  
Ervin Tal-Gutelmacher ◽  
Miles Page ◽  
...  

Herein, we report a Ru-rich anode catalyst for alkaline exchange membrane fuel cells. At 80 °C, a fuel cell with a RuPdIr/C anode and Ag based cathode attained a peak power density close to 1 W cm−2 with 0.2 mg cm−2 anode loading in comparison to 0.77 W cm−2 for the cell tested with the same metal loading of Pt.


2005 ◽  
Vol 29 (4) ◽  
pp. 361-369 ◽  
Author(s):  
Zhao-yu Yang ◽  
Li-ming Song ◽  
Rong-feng Shen ◽  
Zhuo Li ◽  
Yu-sheng Lu

2016 ◽  
Vol 41 (4) ◽  
pp. 3023-3037 ◽  
Author(s):  
M. Rahimi-Esbo ◽  
A.A. Ranjbar ◽  
A. Ramiar ◽  
E. Alizadeh ◽  
M. Aghaee

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