Surface Topography Evolution During Long-Run Micro-Stamping of Bipolar Plates (BPPs) and Effects on Corrosion and Contact Resistance Characteristics

2012 ◽  
Author(s):  
M. F. Peker ◽  
Ö. N. Cora ◽  
M. Koç
Keyword(s):  
Surface Roughness ◽  
Contact Resistance ◽  
Coefficient Of Friction ◽  
Mass Production ◽  
Surface Interactions ◽  
Proton Exchange ◽  
Channel Height ◽  
Bipolar Plates ◽  
Forming Process ◽  
Micro Channels

Micro-stamping, as a promising sheet metal forming process for mass production of small parts, can meet the expectations such as durability, strength, surface finish, and low cost for miniaturized metal products and features. The purpose of this research was set to investigate surface interactions during mass manufacturing of micro-stamped sheets, and its consequences; then establish correlations (if any) between surface interactions vs. corrosion and contact resistance of bipolar plates (BPPs) to be used in proton exchange membrane fuel cells (PEMFC). In experimental part of this study, 10,000 SS316L sheet blanks were micro-stamped using a stamping die set with 750 μm-deep micro-channels under 200 kN stamping force, and with a constant stamping speed of 1mm/s. Surface inspections (surface roughness and micro-channel height measurements), corrosion and contact resistance tests were carried out on BPPs. Analysis of variance (ANOVA) technique was utilized to investigate the significance of surface roughness, channel heights, corrosion and contact resistance variations for BPPs. Moreover, three-dimensional (3D) finite element models of micro-stamping process were established to approximate the stress and strain levels as well as coefficient of friction value experienced at contact interface. The results revealed that the roughness values for micro-stamping dies and BPPs followed similar trends during 10,000 micro-stampings. Since surface defects trigger corrosion, the correlation between surface roughness and corrosion resistance of BPPs was found to be direct. Increasing number of surface irregularities (asperities) lowered contact surface area that resulted in increased contact resistance. Finally, comparison of experimental and numerical channel height values showed that the coefficient of friction did not change considerably during the mass production of BPPs, at least within the 10,000 stamping cycle.

The Fabrication of a Micro-Channel for Metallic Bipolar Plates Using a Rubber Pad Forming Process

2014 ◽  
Vol 626 ◽  
pp. 16-26 ◽  
Author(s):  
You Min Huang ◽  
Yi Syun Wu ◽  
Shung Ping Wang
Keyword(s):  
Thickness Distribution ◽  
Flow Distribution ◽  
Bipolar Plate ◽  
Proton Exchange ◽  
Channel Height ◽  
Bipolar Plates ◽  
Forming Process ◽  
Element Analysis ◽  
Metallic Bipolar Plates ◽  
Rubber Pad Forming

A bipolar plate is one the most crucial and costliest of the various components of a proton exchange membrane fuel cell (PEMFC). It is important to reduce the cost of bipolar plate, not only in terms of material, but also in terms of the manufacturing process, to allow the commercialization of PEMFC’s. The performance of PEMFC’s is also of importance. Metallic bipolar plates have been the subject of much attention recently, because of their low material cost, formability and excellent thermal and mechanical prosperities. Therefore, this study uses a rubber pad forming process for stainless 316L steel to fabricate a bipolar plate with serpentine channels. A computational fluid dynamics (CFD) analysis is performed, in order to determine the influence of channel geometries, such as channel width, channel height and rib width, on the flow distribution of the reactant. Using the CFD results, finite element analysis models are then constructed and the formability of the micro-flow channel is studied. Finality, experiments are conducted to determine the channel height and thickness distribution of the bipolar plate. The numerical results are verified by the experimental results.

Decreasing contact resistance in proton-exchange membrane fuel cells with metal bipolar plates

2013 ◽  
Vol 227 ◽  
pp. 137-144 ◽  
Author(s):  
Christopher J. Netwall ◽  
Benjamin D. Gould ◽  
Joseph A. Rodgers ◽  
Nicholas J. Nasello ◽  
Karen E. Swider-Lyons
Keyword(s):  
Fuel Cells ◽  
Contact Resistance ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Bipolar Plates ◽  
Exchange Membrane

Influence of Surface Roughness on Friction and Contact Resistance in Sliding Electrical Contacts

2007 ◽  
Author(s):  
Dinesh G. Bansal ◽  
Jeffrey L. Streator
Keyword(s):  
Surface Roughness ◽  
Contact Resistance ◽  
Coefficient Of Friction ◽  
Electrical Contact ◽  
Electrical Current ◽  
Electrical Contacts ◽  
Sliding Electrical Contacts ◽  
The Coefficient Of Friction ◽  
Current Densities

An experiment is conducted to investigate the role of surface roughness on the coefficient of friction and contact resistance of sliding electrical contacts. A hemispherical pin is sliding along both smooth and rough 2-meter rail surface. Tests are performed at both low and moderate sliding speed and for a range of electrical current densities, ranging from 0 to about 12 GA/m2. It was found that surface roughness had a significant influence on the coefficient of friction, with the smoother surfaces exhibiting higher coefficients of friction. Contact resistance, on the other hand, did not show as strong an effect of surface roughness, except for a few parameter combinations. At the higher current densities studied (>10 GA/m2), it was found that the contact resistance values tended to be on the order of 1 mΩ, independent of load, speed and roughness. This convergence may be due to presence of liquid metal film at the interface, which established ideal electrical contact.

The Cylindrical Structure of Metallic Bipolar Plates for Proton Exchange Membrane Fuel Cell

2011 ◽  
Vol 228-229 ◽  
pp. 1029-1034
Author(s):  
Jian Lan ◽  
Chen Ni ◽  
Lin Hua
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Bipolar Plate ◽  
Proton Exchange ◽  
Battery Life ◽  
Membrane Electrode ◽  
Bipolar Plates ◽  
Forming Process ◽  
Cylindrical Structure ◽  
Exchange Membrane

As a key component of proton exchange membrane fuel cell (PEMFC), the bipolar plate’s performance will directly affect the power output and battery life of the fuel cell. The conventional metallic bipolar plate is prone to warp, and has large flatness error with residual stress induced by forming process. This will result in contacting incompletely with membrane electrode assemblies (MEA) and lower fuel cell efficiency. A cylindrical structure of the PEMFC metallic polar plate is proposed to improve its stiffness and to reduce assembling error of the fuel cell. The polar plate features, which were originally designed on a flat surface, are projected onto the cylindrical surface with a certain curvature. Two cylindrical polar plates are welded together to become a bipolar plate. The finite element method is applied to compare the stiffness of the conventional and cylindrical polar & bipolar plates. The cylindrical bipolar plate has better stiffness and anti-warping than the conventional bipolar plate. The feasibility of the cylindrical structure is verified by experiment and provides a new idea for the improvement of the bipolar plate and fuel cell stack.

Die Design of Aluminum Bipolar Plate Fabrication by Stamping Process and its Investigation

2012 ◽  
Vol 445 ◽  
pp. 108-113 ◽  
Author(s):  
H.J. Kwon ◽  
Y.P. Jeon ◽  
Chung Gil Kang
Keyword(s):  
Aluminum Alloy ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Bipolar Plate ◽  
Proton Exchange ◽  
Die Design ◽  
Bipolar Plates ◽  
Micro Channels ◽  
The Cost ◽  
Exchange Membrane

A Proton Exchange Membrane Fuel Cell (PEMFC) is a type of fuel cell being developed for automotive applications as well as for stationary fuel cell applications and portable fuel cell applications. Its performance such as power density can be improved by the use of the bipolar plate with a new lightweight material which is one of core components making up PEMFC stack. Aluminum alloy has good mechanical properties not only in terms of density, electrical resistivity and thermal conductivity, but also in terms of corrosion resistant compared with stainless steel and graphite composites bipolar plate. Furthermore, the use of aluminum for a bipolar plate reduces simultaneously the cost and weight of it, and it contributes to the ease of machining. For these reason, an aluminum alloy is selected in this study. This study presents the feasibility of the simulation for the development of aluminum bipolar plates that consists of multi array micro channels. The analytical solutions obtained by the simulation are validated by the comparison with the experimental results. From the results, it is ensured that the stamping processes for the bipolar plate could be predicted and designed by the results of the by FE-Simulation.

Simulation Methodology on Analyzing Clamping Mode for Single Proton Exchange Membrane Fuel Cell

2011 ◽  
Vol 27 (4) ◽  
pp. 545-558 ◽  
Author(s):  
C.-Y. Wen ◽  
H.-T. Chang ◽  
T.-W. Luo
Keyword(s):  
Contact Resistance ◽  
Proton Exchange Membrane ◽  
Three Dimensional ◽  
Gas Diffusion ◽  
Point Load ◽  
Proton Exchange ◽  
Fe Model ◽  
Bipolar Plates ◽  
Interfacial Pressure ◽  
Exchange Membrane

ABSTRACTIn proton exchange membrane fuel cells (PEMFCs), a low interfacial pressure between the bipolar plates and the membrane exchange assembly (MEA) results in a high contact resistance. Conversely, an excessive interfacial pressure reduces the porosity of the gas diffusion layer (GDLs) and may damage the proton exchange membrane (PEM). Consequently, the performance of a PEMFC is critically dependent upon the clamping method. Accordingly, this study emphasizes the development of a numerical methodology for analyzing clamping of a PEMFC and constructs a detailed three-dimensional (3D) full-scale finite element (FE) model of a PEMFC with the traditional and most popular point-load design as an example. The numerical method is first validated by experiments. A series of simulations are then performed on the example cases (i.e. 2-bolt, 4-bolt or 6-bolt) to analyze their behaviors on the contact pressure between the bipolar plates and the MEA and the corresponding effects on the GDL porosity and the contact resistance, under the constraints that the membrane and gaskets remain within their respective elastic limits and the porosity of the GDL has a value higher than 0.5. Overall, to complete the analysis procedures proposed in this paper, the results show that the six-bolt clamping mode with a tightening torque of 16 N-m achieves a uniform pressure distribution and a high interfacial pressure, and therefore represents the optimal clamping mode for the performed example cases.

scholarly journals Micro channels in macro thermal management solutions

2006 ◽  
Vol 10 (1) ◽  
pp. 81-98
Author(s):  
Boris Kosoy
Keyword(s):  
Surface Roughness ◽  
Thermal Management ◽  
High Performance ◽  
Electronic Device ◽  
Three Dimensional ◽  
Thermal Control ◽  
Consumer Products ◽  
Working Fluid ◽  
Channel Height ◽  
Micro Channels

Modern progress in electronics is associated with increase in computing ability and processing speed, as well as decrease in size. Future applications of electronic devices in aviation, aero space and high performance consumer products? industry demand on very stringent specifications concerning miniaturization, component density, power density and reliability. Excess heat produces stresses on internal components inside the electronic device, thus creating reliability problems. Thus, a problem of heat generation and its efficient removal arises and it has led to the development of advanced thermal control systems. Present research analyses a thermodynamic feasibility of micro capillary heat pumped net works in thermal management of electronic systems, considers basic technological constrains and de sign availability, and identifies perspective directions for the further studies. Computer Fluid Dynamics studies have been per formed on the laminar convective heat transfer and pressure drop of working fluid in silicon micro channels. Surface roughness is simulated via regular constructal, and stochastic models. Three-dimensional numerical solution shows significant effects of surface roughness in terms of the rough element geometry such as height, size, spacing and the channel height on the velocity and pressure fields.

scholarly journals Effects of the Synthesis Coating Parameters for Metal Bipolar Plates

2020 ◽  
Vol 49 (12) ◽  
pp. 3125-3134
Author(s):  
Nur Fawwaz Asri ◽  
Teuku Husaini ◽  
Abu Bakar Sulong ◽  
Edy Herianto Majlan
Keyword(s):  
Fuel Cell ◽  
Contact Resistance ◽  
Gas Flow ◽  
Corrosion Current ◽  
Metal Plate ◽  
Proton Exchange ◽  
Design Parameters ◽  
Bipolar Plates ◽  
Coating Materials ◽  
Metal Plates

Metallic bipolar plates tendency to have high contact resistance, but also very susceptible to corrosion. This may decrease in the performance of fuel cells after several times of usage in fuel cell applications. Research has shown that after a metal plate was coated, the characteristic of materials dependent on the type, composition of the coating materials and the method. This study determines design of coating parameters including gas flow rate, DC power, and deposition time of coating for metal bipolar plates, which can be an indicator of the suitability of these plates for use as bipolar plates in proton exchange membrane fuel cell (PEMFC) applications. The aim of this research was to obtain a limitation range value of parameters that can be used as a standard for the use of metal plates as bipolar plates. The optimization parameters designed by Taguchi are used to determine the characteristics of interfacial contact resistance (ICR) and corrosion current density (Icorr). The integration of the Taguchi method with simulation can show the optimal design parameters of the coating on the various materials use. The optimization feature based on Taguchi is applied to ICR and Icorr values, to determine the feasibility of metal plates as potential bipolar plates in PEMFC.

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