Measurement Technique of Mass Transport Phenomena through Complex Material Using NMR Method Applications to a Polymer Electrolyte Membrane for Fuel Cell

Understanding the water transport in the Porous Transport Layer (PTL) is important to improve the operational performance of polymer electrolyte membrane fuel cells (PEMFC). High water content in the PTL and flow channel decreases the transport of the gas reactants to the polymer electrolyte membrane. Dry operating conditions result in increased ohmic resistance of the polymer electrolyte membrane. Both cases result in decreased fuel cell performance. Multi-phase flow in the PTL of the fuel cell is simulated as a network of pores surrounded by the solid material. The pore-phase and the solid-phase of the PTL are generated by varying the parameters of the Weibull distribution function. In the network model, the mass transfer takes place in the pore-phase and the bulk heat transfer takes place in the both the solid-phase and liquid phase of the PTL. Previous studies have looked at the thermal and mass transport in the porous media considering the pore size distribution. In the present study, the sensitivity of the thermal and mass transport to the different arrangements of the solid-phase is carried out and the effect of different solid-phase distributions on the thermal and liquid transport in PTL of PEM fuel cell are discussed.

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Effect of Operating Conditions on the Water Transport Phenomena at the Cathode of Polymer Electrolyte Membrane Fuel Cell

ASME 2009 7th International Conference on Fuel Cell Science, Engineering and Technology ◽

10.1115/fuelcell2009-85217 ◽

2009 ◽

Author(s):

Sang Hern Seo ◽

Chang Sik Lee

Keyword(s):

Fuel Cell ◽

Polymer Electrolyte ◽

Water Transport ◽

Flow Rate ◽

Water Droplet ◽

Polymer Electrolyte Membrane ◽

Transport Phenomena ◽

Operating Conditions ◽

Water Flooding ◽

Electrolyte Membrane

Water management is very important for polymer electrolyte membrane fuel cell because the fuel cell performance is decreased by flooding phenomena generated by liquid water in the cathode channels. In addition, the proton conductivity and water transport of membrane could become different by hydration contents of membrane. This study is observed water transport phenomena of cathode channels with a polymer electrolyte membrane fuel cell according to various operating conditions. In order to obtain the water images, the transparent fuel cell consists of polycarbonate window of the cathode end plate and gold coated stainless steel as the flow field and current collector of the cathode. To investigate the effects of operating conditions on the water transport, experiments were conducted under various operating conditions such as cell temperature, cathode flow rate and cathode backpressure. As operating time elapsed, it is observed that the water droplet formation, growth, coalescence and removal occurred in the cathode channel. It can be known that the high cathode flow rate prevents water flooding by removal of water in the cathode flow channel. Also, the quantity of water droplet was increased by the high cathode backpressure.

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