Measurements of Heat and Mass Transport Characteristics Through PEMFC GDL

2011 ◽  
Author(s):  
Takuto Araki ◽  
Nobuyoshi Tachibana ◽  
Haruki Kaneko ◽  
Koichi Ota
Keyword(s):  
Mass Transport ◽  
Contact Resistance ◽  
Proton Exchange Membrane ◽  
Thermal Characteristics ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
High Porosity ◽  
Special Effects ◽  
Fuel Cell Performance ◽  
Diffusive Resistance

For further improvement of PEMFC (Proton Exchange Membrane Fuel Cell) performance, an optimal design based not only on empirical knowledge but also systematic physical laws and numerical simulation is desirable. However, even basic parameters such as mass transport and thermal characteristics through layers are not completely clear. A GDL (Gas Diffusion Layer) is one of the key components of PEMFC, and its property strongly affects the temperature distribution, diffusion limitation, and flooding. Thus, we measured the diffusivity and thermal conductivity inside a GDL and at its surface boundaries. Anisotropic diffusivity was observed inside the GDL. The measured diffusivities inside the GDL were 59% lower than the value without a GDL in the thickness direction and 25% lower in plane direction. The measured diffusive resistance at the GDL surface was not considerably different from that achieved through conventional laminar analysis, although some special effects would have been observed at the GDL surface because of its high porosity. Regarding the thermal characteristics, the contact resistance at the GDL surface was measured to be as large as the resistance inside the GDL. However, the contact resistance became extremely small when the GDL contained water.

The Effect of Catalyst Coated Diffusion Media on PEM Fuel Cell Performance

2009 ◽  
Author(s):  
Derek W. Fultz ◽  
Po-Ya Abel Chuang
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Thermal Contact ◽  
Electrical Contact ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Hot Press ◽  
Fuel Cell Performance ◽  
Diffusion Media ◽  
A Cell

Two fuel cell architectures, differing only by the surfaces onto which the electrodes were applied, have been analyzed to determine the root causes of dissimilarities in performance. The basic proton exchange membrane fuel cell (PEMFC) is comprised of the proton transporting membrane, platinum-containing anode and cathode electrodes, porous carbon fiber gas diffusion media (GDM), and flow fields which deliver the reactant hydrogen and air flows. As no optimal cell design currently exists, there is a degree of latitude regarding component assembly and structure. Catalyst coated diffusion media (CCDM) refers to a cell architecture option where the electrode layers are coated on the GDM layers and then hot-pressed to the membrane. Catalyst coated membrane (CCM) refers to an architecture where the electrodes are transferred directly onto the membrane. A cell with CCDM architecture has tightly bonded interfaces throughout the assembly which can result in lower thermal and electrical contact resistances. Considering the fuel cell as a 1-D thermal system, the through-plane thermal resistance was observed to decrease by 5–10% when comparing CCDM to CCM architectures. This suggests the thermal contact resistance at the electrode interfaces was significantly reduced in the hot-press process. In addition, the electrical contact resistances between the electrode and GDM were observed to be significantly reduced with a CCDM architecture. This study shows that these effects, which have a potential to increase performance, can be attributed to the hot-press lamination process and use of CCDM architecture.

scholarly journals Numerical Investigation Of Thermodiffusion Effects On PEM Fuel Cell Performance

2021 ◽  
Author(s):  
Rihab. Jaralla
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Finite Thickness ◽  
Pem Fuel Cell ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Operating Pressure ◽  
Fuel Cell Performance ◽  
Catalyst Layers ◽  
Diffusion Layers

A novel mathematical model for an entire proton exchange membrane fuel cell (PEMFC) is developed with its focus placed on the modeling and assessment of thermodiffusion effects that have been neglected in previous studies. Instead of treating catalyst layers as interfaces of nil thickness, the model presented here features a finite thickness employed for catalyst layers, allowing for a more realistic description of electrochemical reaction kinetics arising in the operational PEMFC. To account for the membrane swelling effect, the membrane water balance is modeled by coupling the diffusion of water, the pressure variation, and the electro-osmotic drag. The complete model consisting of the equations of continuity, momentum, energy, species concentrations, and electric potentials in different regions of a PEMFC are numerically solved using the finite element method implemented into a commercial CFD (Comsol 3.4) code. Various flow and transport phenomena in an operational PEMFC are simulated using the newly developed model. The resulting numerical simulations demonstrate that the thermodiffusion has a noticeable impact on the mass transfer for the oxygen. It is also revealed through a systematic parametric study that, as the porosity of gas diffusion layers and catalyst layers increase, the current density of an operational PEMFC may increase. Also, it is found that a PEM fuel cell can perform better with reasonable high operating pressure and temperature, as well as a supply of fully humidified gaseous reactants.

Enhancement of proton exchange membrane fuel cell performance by titanium-coated anode gas diffusion layer

2014 ◽  
Vol 39 (36) ◽  
pp. 21177-21184 ◽  
Author(s):  
Sheng-Yu Fang ◽  
Lay Gaik Teoh ◽  
Rong-Hsin Huang ◽  
Kan-Lin Hsueh ◽  
Ko-Ho Yang ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Diffusion Layer ◽  
Proton Exchange Membrane ◽  
Gas Diffusion Layer ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Cell Performance ◽  
Fuel Cell Performance ◽  
Exchange Membrane

Effect of Compressive Pressure on the Contact Behavior Between Bipolar Plate and Gas Diffusion Layer in a Proton Exchange Membrane Fuel Cell

2014 ◽  
Vol 11 (4) ◽  
Author(s):  
Guo Li ◽  
Jinzhu Tan ◽  
Jianming Gong
Keyword(s):  
Contact Resistance ◽  
Contact Area ◽  
Proton Exchange Membrane ◽  
Bipolar Plate ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Contact Resistivity ◽  
Clamping Force ◽  
Compressive Pressure ◽  
Exchange Membrane

The clamping force during the assembly of proton exchange membrane (PEM) fuel cells has a great influence in the contact resistance between bipolar plate (BPP) and gas diffusion layer (GDL). In this paper, three different types of carbon papers are used as GDL materials. The contact resistance between BPP and GDL is measured under different applied clamping torques. Based on experimental data, a relationship of compressive pressure resulting from the applied clamping torque and contact resistivity is established by the least square method. Based on the commercial code abaqus, a program is developed to predict the contact resistivity. In addition, the changes of contact pressure, contact area, and porosity of GDL are studied. The experimental result shows that the contact resistivity nonlinearly decreases with increasing of the applied clamping torque. The thicker GDL without fillers has a higher contact resistivity. Finite element analysis (FEA) results show that both contact area and contact pressure increase with increasing of the compressive pressure in the same fillet radius of the rib, except that the fillet radius is zero. The porosity decreases with increase of the clamping force. The contact resistivity is consistent with the experimental results. So it can be predicted very well.

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