Effect of Hydrophobicity in Cathode Porous Media on PEM Fuel Cell Performance

2010 ◽  
Vol 7 (6) ◽  
Author(s):  
Lijun Yang ◽  
Wenan Li ◽  
Xiaoze Du ◽  
Yongping Yang
Keyword(s):  
Fuel Cell ◽  
Flow Field ◽  
Water Content ◽  
Liquid Water ◽  
Pem Fuel Cell ◽  
Liquid Water Content ◽  
Contact Angles ◽  
Water Flooding ◽  
Water Transportation ◽  
Overall Performance

Water management is a key issue for the performance of a polymer electrolyte membrane (PEM) fuel cell. Materials of the fuel cell would affect the water transportation in the flow field, thus influence, the overall performance of the fuel cell. A three dimensional, single-channel, counterflow model was built to analyze the performance of the PEM fuel cell. Different surface contact angles were set to the liquid water droplets in the catalyst layers (CLs) and gas diffusion layers (GDLs) to present the different wetting property characterizations of the materials. Assuming that the contact angle ranges from 75 deg to 150 deg, the liquid water content and distribution in the cathode GDL were investigated in details. Numerical analysis showed that the hydrophobicity of the structure affects the water transportation in the fuel cell significantly. Hydrophobic materials could lower the rate of water saturation in the flow field, thus preventing the water flooding in the cathode side. When the surface contact angles of the cathode CL and GDL were set to 135 deg, the liquid water content is least in the GDL. I-V polarization curves of the fuel cell with different materials were also developed to analyze the overall performance. As a result, proper hydrophobic material would lower the rate of cathode water flooding in PEM and benefit the performance of PEM fuel cell.

Effect of Hydrophobicity in Cathode Porous Media on PEM Fuel Cell Performance

2009 ◽  
Author(s):  
Lijun Yang ◽  
Wenan Li ◽  
Xiaoze Du ◽  
Yongping Yang
Keyword(s):  
Fuel Cell ◽  
Flow Field ◽  
Water Content ◽  
Liquid Water ◽  
Pem Fuel Cell ◽  
Liquid Water Content ◽  
Contact Angles ◽  
Water Flooding ◽  
Water Transportation ◽  
Overall Performance

The water management is a key issue for the performance of a polymer electrolyte membrane (PEM) fuel cell. Materials of the fuel cell would affect the water transportation in the flow field thus influence the overall performance of a fuel cell. Three dimensional single-channel, counter-flow model was built to analyze the performance of PEM fuel cell. Different surface contact angles were set to the liquid water droplets in the catalyst layers (CL) and gas diffusion layers (GDL) to present the different wetting property characterizations of the materials. Assuming that the contact angles range from 75° to 150°, the liquid water content and distribution in the cathode GDL were investigated in details. Numerical analysis showed that the hydrophobicity of the structure affects water transportation in the fuel cell significantly. Hydrophobic materials could lower the rate of water saturation in the flow field thus prevent the water flooding in the cathode side. When the surface contact angel of cathode CL and GDL was set to 135°, the liquid water content is least in the GDL. I-V polarization curves of the fuel cell with different materials were also developed to analyze the overall performance. As a result, proper hydrophobic material would lower the rate of cathode water flooding in PEM and benefit the performance of PEM fuel cell.

Analysis of Pressure Drop and Water Flooding of Two-Phase Flow Along Channels for a PEM Fuel Cell System

2009 ◽  
Author(s):  
Jinglin He ◽  
Song-Yul Choe ◽  
Chang-Ouk Hong
Keyword(s):  
Fuel Cell ◽  
Pressure Drop ◽  
Relative Humidity ◽  
Liquid Water ◽  
Water Distribution ◽  
Gas Flow ◽  
Pem Fuel Cell ◽  
Cell System ◽  
Water Flooding ◽  
Two Phase

The flow in gas flow channels of an operating polymer electrolyte membrane (PEM) fuel cell has a two-phase characteristic that includes air, water vapor and liquid water and significantly affects the water flooding, pressure distribution along the channels, and subsequently the performance of the cell and system. Presence of liquid water in channels prevents transport of the reactants to the catalysts and increases the pressure difference between the inlet and outlet of channels, which leads to high parasitic power of pumps used in air and fuel supply systems. We propose a model that enables prediction of pressure drop and liquid water distribution along channels and analysis of water flooding in an operating fuel cell. The model was developed based on a gas-liquid two-phase separated flow that considers the variations of gas pressure, mass flow rate, relative humidity, viscosity, void fraction, and density along the channels on both sides. Effects of operating parameters that include stoichoimetric ratio, relative humidity, and inlet pressure on the pressure drop and water flooding along the channels were analyzed.

Effect of Porosity Gradient in Gas Diffusion Layer on Cell Performance With Thin-Film Agglomerate Model in Cathode Catalyst Layer of a PEM Fuel Cell

2011 ◽  
Author(s):  
Chun-I Lee ◽  
Shiqah-Ping Jung ◽  
Kan-Lin Hsueh ◽  
Chi-Chang Chen ◽  
Wen-Chen Chang
Keyword(s):  
Thin Film ◽  
Fuel Cell ◽  
Diffusion Layer ◽  
Liquid Water ◽  
Water Saturation ◽  
Catalyst Layer ◽  
Gas Diffusion Layer ◽  
Pem Fuel Cell ◽  
Gas Diffusion ◽  
Water Flooding

A one-dimensional, steady-state, two-phase, isothermal numerical simulations were performed to investigate the effect on cell performance of a PEM fuel cell under non-uniform porosity of gas diffusion layer. In the simulation, the non-uniform porosity of gas diffusion layer was taken into account to analyze the transport phenomena of water flooding and mass transport in the gas diffusion layer. The porosity of the gas diffusion layer is treated as a linear function. Furthermore, the structure of the catalyst layer is considered to be a cylindrical thin-film agglomerate. Regarding the distribution analysis of liquid water saturation, oxygen concentration and water concentration depend on the porosity of gas diffusion layer. In the simulation, the εCG and εGC represent the porosity of the interfaces between the channel and gas diffusion layer and the gas diffusion layer and the catalyst layer, respectively. The simulation results indicate that when the (εCG, εGC) = (0.8, 0.4), higher liquid water saturation appears in the gas diffusion layer and the catalyst layer. On the contrary, when the (εCG, εGC) = (0.4, 0.4), lower liquid water saturation appears. Once the liquid water produced by the electrochemical reaction and condensate of vapor water may accumulate in the open pores of the gas diffusion layer and reduced the oxygen transport to the catalyst sites. This research attempts to use a thin-film agglomerate model, which analyze the significant transport phenomena of water flooding and mass transport under linear porosity gradient of gas diffusion layer in the cathode of a PEM fuel cell.

Experimental Investigation of Liquid Water Formation and Transport in a Transparent Single-Serpentine PEM Fuel Cell

2006 ◽  
Author(s):  
Dusan Spernjak ◽  
Suresh Advani ◽  
Ajay K. Prasad
Keyword(s):  
Fuel Cell ◽  
Flow Field ◽  
Liquid Water ◽  
Catalyst Layer ◽  
Pem Fuel Cell ◽  
Gas Diffusion ◽  
Operating Conditions ◽  
Cathode Side ◽  
Water Formation ◽  
Transparent Cell

Liquid water formation and transport was investigated by direct experimental visualization in an operational transparent single-serpentine PEM fuel cell. We examined the effectiveness of various gas diffusion layer (GDL) materials in removing water away from the cathode and through the flow field over a range of operating conditions. Complete polarization curves as well as time evolution studies after step changes in current draw were obtained with simultaneous liquid water visualization within the transparent cell. At similar current density (i.e. water production rate), lower level of cathode flow field flooding indicated that liquid water had been trapped inside the GDL pores and catalyst layer, resulting in lower output voltage. No liquid water was observed in the anode flow field unless cathode GDLs had a microporous layer (MPL). MPL on the cathode side creates a pressure barrier for water produced at the catalyst layer. Water is pushed across the membrane to the anode side, resulting in anode flow field flooding close to the H2 exit.

scholarly journals Proof of Concept: Development of Snow Liquid Water Content Profiler Using CS650 Reflectometers at Caribou, ME, USA

Sensors ◽  
2017 ◽  
Vol 17 (3) ◽  
pp. 647 ◽  
Author(s):  
Carlos Pérez Díaz ◽  
Jonathan Muñoz ◽  
Tarendra Lakhankar ◽  
Reza Khanbilvardi ◽  
Peter Romanov
Keyword(s):  
Water Content ◽  
Liquid Water ◽  
Liquid Water Content ◽  
Concept Development ◽  
Proof Of Concept
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