Flow-Channel Shape Design of Stamped Bipolar Plate for PEM Fuel Cell by Micro-Forming Simulation

2006 ◽  
Author(s):  
Linfa Peng ◽  
Xinmin Lai ◽  
Jun Ni ◽  
Z. Q. Lin
Keyword(s):  
Fuel Cell ◽  
Pem Fuel Cell ◽  
Bipolar Plate ◽  
Pem Fuel Cells ◽  
Flow Channel ◽  
Micro Forming ◽  
Channel Depth ◽  
Forming Process ◽  
Forming Simulation ◽  
Punch Radius

PEM fuel cells are promising candidate as most environmentally friendly power source for transport and stationary cogeneration applications due to its high efficiency, high power density, fast startup and system robustness. But the PEM fuel cell is still too expensive for widespread commercialization. Bipolar plate is one of the most important and costliest components of PEM fuel cells and accounts to more than 80% of the weight and 30% of the total cost in a fuel cell stack. To reduce the cost and weight of fuel cell stacks and at the same time meeting several technical requirements for mass production, a prototype of low-cost stamped bipolar plates made of stainless steel 316 sheets has been introduced in this paper. Base on micro sheet forming process simulation experiments, the influence of some key dimensions of the flow channel to the formability of the stamped polar plate is also detailedly studied. Micro-forming simulation results show that relative punch radius r/t (punch radius r, sheet thickness t) and the ration of the width of coolant channel to channel depth w/h (width of coolant channel w, channel depth h) are import factors that decide the final formability of the whole polar plate. Large r/t is recommended for compact flow channel design and larger w/t is recommended for safer forming process.

PEM Fuel Cell Bipolar Plate Reliability and Material Selection

2003 ◽  
Author(s):  
Michael J. Ajersch ◽  
Michael W. Fowler ◽  
Kunal Karan ◽  
Brant A. Peppley
Keyword(s):  
Fuel Cells ◽  
Life Cycle ◽  
Fuel Cell ◽  
Failure Modes ◽  
Material Selection ◽  
Pem Fuel Cell ◽  
Bipolar Plate ◽  
Pem Fuel Cells ◽  
Cycle Performance ◽  
Bipolar Plates

The majority of the research on PEM fuel cells to date has been focused on assessing fuel cell behavior in the early stages of its life cycle. However, as widespread commercialization approaches, PEM fuel cells will be required to operate reliably for increasingly longer periods of time. It therefore also becomes equally important to characterize fuel cell performance at the end of its lifecycle. The reliability of a PEM fuel cell is dependent on the material properties, the manufacturing methods, and the design of its individual components. Among these components, the bipolar plates have received the least attention as a factor that may limit a fuel cell’s life cycle performance. Driven by the need for cost and weight reduction of fuel cell stacks, a significant amount of development work has been directed towards the development of new materials and designs for bipolar plates. Selection of an appropriate design and/or material for bipolar plates requires that reliability and durability data must be available, and that testing protocols appropriate and indicative of fuel cell operation be established. This paper provides a review fuel cell bipolar plate reliability and durability. Topics that will be addressed include bipolar plate functionality and design requirements, plate materials selection, plate failure modes. This is followed by a description of new bipolar plate reliability/durability test methods being developed at the CAMM Fuel Cell Research Group.

The Thin Sheet Metal Rubber Pad Stamping for PEM Fuel Cell

2010 ◽  
Vol 150-151 ◽  
pp. 1732-1740 ◽  
Author(s):  
Jian Lan ◽  
Yu Liu ◽  
Xi Wei ◽  
Lin Hua
Keyword(s):  
Fuel Cell ◽  
Sheet Metal ◽  
Thin Sheet ◽  
Shell Element ◽  
Pem Fuel Cell ◽  
Bipolar Plate ◽  
Flow Channel ◽  
Hydraulic Pressure ◽  
Solid Element ◽  
Thin Sheet Metal

Bipolar plate is the key component of proton exchange membrane (PEM) fuel cell and represents a significant part of the overall cost and the total weight in a fuel cell stack. The thin sheet metal, with usually 0.1~0.3mm thickness, deformed to bipolar plate with flow channel 0.5~2mm width and depth, by rubber pad stamping can reduce the cost greatly. The rubber pad is simulated by solid element and hydraulic pressure respectively. Experiment shows that the hydraulic pressure can simulate the rubber pad. The thin sheet metal is modeled by solid element and shell element respectively. Considering thin sheet metal material size effect, the shell element cannot simulate the thin sheet metal stamping process because of small corner radius. Modeling rubber pad by hydraulic pressure and thin sheet metal by solid element, the simulation of the rubber pad stamping process shows that 1) the sheet metal in channel appears large uneven strain with high stress; 2) convex fillet make the sheet metal two direction tensions and should keep large fillet corner. Those simulations are validated by experiments. The research on rubber pad stamping will improve the understanding of this micro forming process and provide design guide of flow channel.

An Innovative Three Dimensional Numerical Model for Bipolar Plates to Enhance the Efficiency of PEM Fuel Cells

2012 ◽  
Author(s):  
Faraz Arbabi ◽  
Ramin Roshandel
Keyword(s):  
Fuel Cell ◽  
Numerical Model ◽  
Three Dimensional ◽  
Pem Fuel Cell ◽  
Bipolar Plate ◽  
Pem Fuel Cells ◽  
Fuel Cell Performance ◽  
Flow Channels ◽  
Plate Design ◽  
Current Densities

The efficiency of proton exchange membrane (PEM) fuel cell is straightly correlated to the bipolar plate design and fluid channel arrangements. Higher produced energy can be attained by optimal design of type, size, or patterns of the channels. Previous researches showed that the bipolar plate channel design has a considerable effect on reactant distribution uniformity as well as humidity control in PEM fuel cells. This paper concentrates on enhancements in the fuel cell performance by optimization of bipolar plate design and channels configurations. A numerical model of flow distribution based on Navier-Stokes equations using individual computer code is presented. The results gained from this three dimensional, multi-component simulation showed excellent agreement with the existed experimental data in the previous publications. In this paper, a new flow field design inspired from the nature is presented and analyzed. In this work, two mostly used flow channels design — serpentine and parallel — have been studied and compared to the newly introduced bio inspired bipolar plate design. To compare, velocity distributions of fluid, mass fraction of reactant gases and polarization curves for different bipolar plate designs have been analyzed. The key design criteria in this study are based on more homogenous molar spreading of species and more uniform velocity distribution along the flow channels and also higher voltage and power density output in different current densities. By developing a numerical code it was concluded that the bio inspired bipolar plate can enhance the PEM fuel cell performance especially at middle current densities, where the losses caused by mass transport limitations are not significant.

Manufacturing and Evaluation of Fiber-Reinforced Composite Bipolar Plate for PEM Fuel Cell

2006 ◽  
Author(s):  
Hee-Sub Lee ◽  
Sung-Hoon Ahn ◽  
Ui-Sik Jeon ◽  
Sang-Yeoul Ahn ◽  
Byung-Ki Ahn
Keyword(s):  
Surface Roughness ◽  
Fuel Cell ◽  
Epoxy Resin ◽  
Electric Conductivity ◽  
Pem Fuel Cell ◽  
Bipolar Plate ◽  
Pem Fuel Cells ◽  
Mixing Ratio ◽  
Carbon Fabric ◽  
Graphite Particles

The fuel cell is one of promising environment-friendly energy sources for the next generation. The bipolar plate is a major component of the PEM fuel cell stack, which takes a large portion of stack cost. In this study, as alternative materials for bipolar plate of PEM fuel cells, graphite composites were fabricated by compression molding. Graphite particles mixed with epoxy resin were used as the main substance to provide electric conductivity. To achieve desired electrical properties, specimens were made with different mixing ratio, processing pressure and temperature and tested. To increase mechanical strength, one or two layers of woven carbon fabric were added to the original graphite and resin composite. Thus, the composite material was consisted of three phases: graphite particles, epoxy resin, and carbon fabric. By increasing mixing ratio of graphite, fabricated pressure and process temperature, electric conductivity of the composite were improved. The results of tensile test showed that the tensile strength of the two-phase graphite composite was about 4 MPa, and that of three-phase composite was increased to 57 MPa. As surface properties, contact angle and surface roughness were tested. Contact angles were higher than 100°. The average surface roughness was 0.96 μm.

Flow channel shape optimum design for hydroformed metal bipolar plate in PEM fuel cell

2008 ◽  
Vol 178 (1) ◽  
pp. 223-230 ◽  
Author(s):  
Linfa Peng ◽  
Xinmin Lai ◽  
Dong’an Liu ◽  
Peng Hu ◽  
Jun Ni
Keyword(s):  
Fuel Cell ◽  
Optimum Design ◽  
Pem Fuel Cell ◽  
Bipolar Plate ◽  
Flow Channel ◽  
Channel Shape

Optimization of PEM Fuel Cell Flow Channels: Modeling Analysis and Experimental Tests

2013 ◽  
Author(s):  
Hong Liu ◽  
Peiwen Li
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Experimental Work ◽  
Gas Flow ◽  
Current Collector ◽  
Pem Fuel Cell ◽  
Pem Fuel Cells ◽  
Flow Channel ◽  
Flow Channels ◽  
Modeling Analysis

The dimensions of gas flow channels and walls/ribs of PEM fuel cells are optimized using a convenient mathematical model. Experimental work for several PEM fuel cells with modeling-optimized gas flow channels was conducted, and the tested results validate the modeling work and the optimization. The model considered average mass transfer and species’ concentrations in flow channels, which allows the determination of an average concentration polarization, the humidity in anode and cathode gas channels, and thus the proton conductivity of membranes, as well as the activation polarization. An electrical circuit for the current and ion conduction is applied to analyze the ohmic losses from anode current collector to cathode current collector. The modeling computation required relatively less computational time and thus can be applied to compute a large number of cases with various flow channel designs and operating parameters for optimization analysis. Optimum ratio of the width of flow channels against the walls/ribs was found from the modeling analysis. In the experimental work, PEM fuel cells were fabricated based on the flow channel dimensions optimized from the modeling analysis. Experimental results agreed with the modeling analysis satisfactorily in respect to the comparison of V-I performance between fuel cells with several optimized designs. The model is recommended as a tool for optimization design of gas flow channels for PEM fuel cells. The optimization results are of significance to the improvement of PEM fuel cell designs and performance.

Initial Development of a Method for Optical Measurement of Water Droplet Formation in the Cathode Flow Channel of a PEM Fuel Cell

2013 ◽  
Author(s):  
Hannah Stuart ◽  
Kristopher Inman ◽  
Xia Wang
Keyword(s):  
Fuel Cell ◽  
Water Droplet ◽  
Pem Fuel Cell ◽  
Pem Fuel Cells ◽  
Droplet Formation ◽  
Flow Channel ◽  
Operating Conditions ◽  
Ex Situ ◽  
Flow Channels ◽  
Water Formation

Cathode flooding in Proton Exchange Membrane (PEM) fuel cells, or the displacement of reactant gases from the catalyst layer by water formation, limits performance and durability. Water transport is not yet well understood and can vary under different operating conditions, such as temperature. Previous work performed to characterize water formation has mostly involved water visualization, using materials/construction which could alter water condensation characteristics. The objective of this work is to investigate a method to optically measure the relative size of water droplet formation in PEM fuel cell cathode gas flow channels using an unobtrusive and previously developed temperature sensor. A single-sensor mathematical model was developed which considers channel geometry, fiber diameter, and water droplet shape and size. Droplet formation involved three different possible shapes, resulting from different hydrophobic properties of channel material. Ex situ testing utilized chromium doped yttrium aluminum garnet as the chosen phosphor, applied to a carbon paper GDL. No correlation was found between the theoretical model and the experimental findings. Although signal attenuation cannot accurately predict droplet size, it is still possible to characterize water droplet formation using statistical analysis. Since a water droplet consistently produces measurable attenuation, the frequency of water droplet detection in the flow channel can be used to characterize the amount of water formation or flooding in the cathode flow channels. The work is ongoing and new methods of water droplet characterization are still being investigated.

Thermal and Coolant Flow Computational Analysis of Cooling Channels for an Air-Cooled PEM Fuel Cell

2011 ◽  
Vol 110-116 ◽  
pp. 2746-2753 ◽  
Author(s):  
W.A.N. W. Mohamed ◽  
M.F. Remeli ◽  
A.H.A. Hamid ◽  
R. Atan
Keyword(s):  
Fuel Cell ◽  
Electrical Power ◽  
Pem Fuel Cell ◽  
Bipolar Plate ◽  
Pem Fuel Cells ◽  
Coolant Flow ◽  
Dynamics Simulation ◽  
Plate Temperature ◽  
Cooling Channels ◽  
Rectangular Configuration

Polymer Electrolyte Membrane (PEM) fuel cells are clean electrical power generators for applications normally up to 100 kW power requirements. It has the advantage of fast start-up due to its low operating temperatures of 60oC to 100oC. However, the low temperature requirement has to be addressed with an efficient thermal management system. For an air-cooled PEM fuel cell, cooling channels with a straight rectangular configuration are widely applied. This work establishes a computational methodology for the analysis of coolant flow mechanics related to the channel geometry for a specific bipolar plate size. The velocity and thermal gradient, average velocity rise factor (AVRF) and total cooling rates were determined from Computational Fluid Dynamics simulation based on initial coolant Reynolds number of approximately 250 to 750 with a steady heat flow of 82W. All geometries showed nearly 100% cooling capability respective to the heat load, but differ in the aspects of average plate temperature achieved, its temperature profile as well as existing gradient. From the analytical perspective of thermo fluids engineering, the selection criteria of suitable micro cooling channel configurations, depending on operating priority, was established.

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