Papers by Keyword: Proton Exchange Membrane Fuel Cell

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Authors: Qian Pu Wang, Michael Eikerling, Da Tong Song, Zhong Sheng Liu
Abstract: A mathematical model for an ultra-thin catalyst layer in PEFCs is introduced. It utilizes Nernst-Planck and Poisson equations. Calculated polarization curves are shown to compare favourably with published experimental data for ultra-thin catalyst layers. Aspects of current conversion, reactant, current distribution, and catalyst utilization are explored. The effect of catalyst layers thickness on the Pt utilization is discussed. This study gives us a better understanding of transport and reaction at the mesoscopic scale and it furnishes the directions for optimization of this type of catalyst layer.
1397
Authors: Qi Li, Wei Rong Chen, Zhi Xiang Liu, Shu Kui Liu, Wei Min Tian
Abstract: A nonlinear model of proton exchange membrane fuel cell (PEMFC) based on an adaptive neuro-fuzzy inference system (ANFIS) is proposed to study different operational conditions effect on the dynamic response of Ballard 1.2kW Nexa power module. A hybrid learning algorithm combining back propagation (BP) and least squares estimate (LSE) is adopted to identify the parameters of input and output membership functions for the improvement of training efficiency in the ANFIS. The comparisons with the experimental data demonstrate that the obtained ANFIS model can efficiently approximate the dynamic output response of Nexa power module and is capable of predicting dynamic performance in terms of stack output voltage with a high accuracy.
1357
Authors: Shi Gang Yu, Hui He, You Sheng Xu
Abstract: A composite three-dimensional mathematical model of proton exchange membrane fuel cell is proposed, the corresponding finite element method and numerical simulation are given as well, where fluid flow, proton transport, and electrochemical reaction are addressed. Some factors that probably affect the performance of the cell are analyzed by using the model. The computational results show that the reactant concentration decreases along the flow direction, the water concentration increases in the cathode side of membrane, membrane resistance decreases, conductivity increases and proton concentration increases. The fuel cell performance is better when the porosity increases, as well as the operating pressure.
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Authors: Alin Cristian Farcaş
Abstract: Water management inside a proton exchange membrane fuel cell is critical both for stable operation and desired performance. This paper presents the relations that govern water transport mechanisms, describes and proposes a control strategy for membrane conductivity manipulation using an observer and two controllers. The Simulink model is showing successful control of membrane conductivity when density current changes while water vapor pressures are maintained within the safe limits. Using the proposed control strategy, further work can be conducted in the area of feed forward and advanced control of water management in PEM fuel cells.
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Authors: Jing Yi Chang, Yean Der Kuan, Yun Siang Weng, Sheng Ching Chan
Abstract: This study developed a heating mechanism applicable to hydrogen storage tank, in order to enhance the stability and durability of proton exchange membrane fuel cell (PEMFC). This study discussed two heating modes. The first mode was using heating wire to wind the hydrogen storage tank body. Heating wires were used to wind the upper, middle and lower parts of the hydrogen storage tank and the whole tank respectively for discussion. The second heating mode was to use the PEMFC cathode waste heat to heat the hydrogen storage tank body. This study discussed the variations of hydrogen release rate and tank body temperature with the hydrogen release time in different heating mechanisms. The research results can serve as reference for system design in various applications.
1352
Authors: Chuan Wu, Ying Bai, Feng Wu, Dan Xian Liu
Abstract: Amorphous Ni-Co-B catalyst was synthesized by a chemical reduction method, and followed by a heat-treating at 100°C, then characterized by X-ray diffraction (XRD), Scanning electronic microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmetr-Teller (BET) analysis, and adopted to help accelerating hydrolysis reaction of NaBH4 alkaline solution. It is proved that the amorphous Ni-Co-B catalyst is not a simple combination of elemental Ni, Co and B, but a multiplex metal boride. It exhibits an maximum hydrogen generation rate of 210 ml/min/(g catalyst) at 100% H2 utilization, which is potentially to give a successive H2 supply for proton exchange membrane fuel cells.
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Authors: Xue Jun Zhang, Hao Pei, Zeng Min Shen
Abstract: Carbon fiber paper was modified by adding carbon nanotubes to make it reach the demand of gas diffusion layer (GDL) by the process of impregnation with phenolic resin solution dispersed with carbon nanotubes, molding, and carbonization. The properties of modified carbon fiber paper, thickness, density, porosity, gas permeability, specific resistance and tensile strength, were characterized. The results indicate that surface treatment is helpful to disperse carbon nanotubes in phenolic resin. Phenolic resin is used to bond the carbon fibers, and carbon nanotube could reduce the specific resistance of the carbon fiber paper. When carbon nanotube content is 5 %, modified carbon fiber paper is prepared with thickness of 0.30 mm, density of 0.43 g/cm3, porosity of 77 %, gas permeability of 2400 mL•mm/(cm2•h•mmAq), specific resistance of 0.020 Ω•cm and tensile strength of 15 MPa, which basically qualifies for the application requirement.
76
Authors: Hai Dan Lin, Xiao Ying Yang, Cheng Xun Sun
Abstract: A new series of hydrophobic-hydrophilic multiblock sulfonated poly (arylene ether ketone)-b-poly (arylene ether ketone) copolymers were successfully synthesized and evaluated for use as proton exchange membranes (PEMs). The membrane properties of block copolymers including ion exchange capacities (IECs), water uptake and proton conductivities were characterized for the multiblock copolymers and compared with random sulfonated poly (arylene ether) s and other multiblock copolymer membranes at similar ion exchange capacity value. This series of multiblock copolymers showed moderate conductivities up to 0.063 S/cm at 80 °C with very low water uptake of 19%. Therefore, they are considered to be promising PEM materials for fuel cells.
1321
Authors: Mostak Ahmed, Mohammad B. Khan, Mubarak A. Khan, Nazia Rahman, S.S. Alam, Hasan T. Imam
Abstract: Poly(ethylenetarepthalate) (PET)-based polymer electrolyte membranes (PEMs) for fuel cells were successfully prepared by grafting of allyl methacrylate (AMA) and allyl acetate separately onto PET films under UV- radiation. A consequent selective sulfonation of the grafted films was performed by chlorosulfonic acid (ClSO¬3H) under milder condition. The sulfonation reaction proceeded at the grafted chains, as a result the grafted films successfully transformed to a PEM. It has been confirmed by titrimetric and gravimetric analyses as well as FTIR spectroscopy. The ion exchanges capacities (IECs) of the PEMs were studied by changing the degree of grafting and sulfonation. IECs of the PEMs prepared by grafting of allylmethacrylate (AMA) and allyl acetate onto PET were found in the ranges of 0.013-0.035 mmol/g and 0.03114-0.04125 mmol/g respectively. Water uptake, acid and hydrogen peroxide tolerance, tensile strength and proton transfer rate of the PEMs were studied. Electrical properties such as resistance, dielectric loss, and capacitance of the PEMs were also studied using impedance analyzer.
1071
Authors: T. Maiyalagan, Sivakumar Pasupathi
Abstract: Fuel cells, as devices for direct conversion of the chemical energy of a fuel into electricity by electrochemical reactions, are among the key enabling technologies for the transition to a hydrogen-based economy. Among the various types of fuel cells, polymer electrolyte membrane fuel cells (PEMFCs) are considered to be at the forefront for commercialization for portable and transportation applications because of their high energy conversion efficiency and low pollutant emission. Cost and durability of PEMFCs are the two major challenges that need to be addressed to facilitate their commercialization. The properties of the membrane electrode assembly (MEA) have a direct impact on both cost and durability of a PEMFC. An overview is presented on the key components of the PEMFC MEA. The success of the MEA and thereby PEMFC technology is believed to depend largely on two key materials: the membrane and the electro-catalyst. These two key materials are directly linked to the major challenges faced in PEMFC, namely, the performance, and cost. Concerted efforts are conducted globally for the past couple of decades to address these challenges. This chapter aims to provide the reader an overview of the major research findings to date on the key components of a PEMFC MEA.
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