The Experts below are selected from a list of 11667 Experts worldwide ranked by ideXlab platform
Yongping Hou - One of the best experts on this subject based on the ideXlab platform.
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Effect of strengthened road vibration on performance degradation of PEM Fuel Cell Stack
International Journal of Hydrogen Energy, 2016Co-Authors: Yongping Hou, Dong Hao, Jianping Shen, Zhang Tao, Hong WangAbstract:Abstract The vehicular Fuel Cell Stack is unavoidably impacted by the vibration and shock in the real-world due to the road unevenness. However, influences of vibration on Fuel Cell Stack have yet to be investigated completely. In this paper, the performance of a Fuel Cell Stack is experimentally studied in terms of gas-tightness, voltage degradation, AC impedance spectra, polarization curve and characteristic parameters in polarization curve through long-term strengthened road vibration tests, in order to investigate the influences of road-induced vibration on performance degradation of Fuel Cell Stack. The vibration tests are carried out on a six-channel multi axial simulation table with the vibration excitation spectra originally derived from the strengthened road of the ground prove. During the vibration test, several kinds of performance test including gas-tightness test, AC impedance diagnosis and polarization curve test are conducted at regular intervals. After the vibration test, the gas leakage rate of anode reaches 1.73 times of the initial value. The open circuit voltage and rated voltage decreases by 0.90% and 3.58%, respectively. Meanwhile, the performance of individual Cell voltage uniformity becomes worse distinctly. With the increase of vibration duration, the ohmic resistance obtained from AC impedance diagnosis ascends approximately linearly and presents a growth of 5.36% ultimately. An improved empirical Fuel Cell polarization curve model is adopted to fit the current–voltage data and estimate the characteristic parameters which decide the shape of polarization curve. It is noted that the limiting current density declines distinctly and the mass transfer loss increases mainly at the range of high current densities. The results indicate that the long-term strengthened road vibration condition exerts a significant influence on the durability of Fuel Cell Stack.
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AC impedance characteristics of a vehicle PEM Fuel Cell Stack under strengthened road vibrating conditions
International Journal of Hydrogen Energy, 2014Co-Authors: Yongping Hou, Xu Zhang, Dong HaoAbstract:Abstract Electrochemical impedance spectroscopy is used in this paper to investigate the performance of the Fuel Cell Stack and single Cells under long-term vibrating conditions on strengthened roads. During strengthened road vibration test, the electrochemical impedance spectra of Fuel Cell Stack and several Cells in the Stack are measured nine times at regular intervals. Parameters of a Randles-like equivalent circuit are fitted to the experimental data. The classical Randles Cell is extended by changing the standard plane capacitor into a constant phase element so that the quality of fit is improved. The results of the electrochemical impedance analysis indicate that the ohmic resistance of the Fuel Cell Stack is nearly linear with the vibration time and reaches a growth of 0.035695% per hour. While the charge transfer resistance of the Fuel Cell Stack during strengthened vibration test ascends after it falls down firstly, and finally tends to be stable. The influence of Cell position on the AC impedance is also studied, and the results of which show that the Cell position has a significant impact on the ohmic resistance.
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Experimental investigation of the steady-state efficiency of Fuel Cell Stack under strengthened road vibrating condition
International Journal of Hydrogen Energy, 2013Co-Authors: Yongping Hou, Dong Hao, Caoyuan Shen, Zhongying ShaoAbstract:Abstract The steady-state efficiency of the Fuel Cell Stack is experimentally investigated in terms of steady-state hydrogen utilization, actual efficiency and maximum efficiency point through a 162 h strengthened vibration test in this paper, in order to analyse the steady-state performance of the Fuel Cell Stack under long-term vibrating condition on strengthened roads. The load spectra applied in the test are simulated by the acceleration signals of the Fuel Cell Stack, which are previously measured in a vehicle vibration test. The load signals of the vehicle vibration test are iterated through a road simulator from vehicle acceleration signals which are originally sampled in the strengthened road of the ground prove. The test results show that the steady-state hydrogen utilization of the Stack decreases by 30.7% during the test. The maximum drop of steady-state actual efficiency is 21.0%. Additionally, the maximum efficiency point of the Stack declines by 5.4%, while the corresponding current experiences an increment of 47.2 A. From the results it can be concluded that the strengthened road vibration exerts a significant influence on the steady-state performance of the Fuel Cell Stack, which cannot and should not be ignored during the research.
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A transient semi-empirical voltage model of a Fuel Cell Stack☆
International Journal of Hydrogen Energy, 2007Co-Authors: Yongping Hou, Mingxi Zhuang, Gang WanAbstract:On the basis of a case study, we first analyze the voltage transient properties of a Fuel Cell Stack. We then propose a semi-empirical model, which has been validated by three test runs in the paper. The results obtained in this paper show that the model-computed values correctly fit the experimental data and ensure that the suggested model is highly able to reflect the transient properties of the Fuel Cell Stack voltage. The advantage of this model lies in a simple structure, represented by a small number of parameters. Therefore, it can easily be applied to the simulation of vehicle dynamics for design aims.
Dong Hao - One of the best experts on this subject based on the ideXlab platform.
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Effect of strengthened road vibration on performance degradation of PEM Fuel Cell Stack
International Journal of Hydrogen Energy, 2016Co-Authors: Yongping Hou, Dong Hao, Jianping Shen, Zhang Tao, Hong WangAbstract:Abstract The vehicular Fuel Cell Stack is unavoidably impacted by the vibration and shock in the real-world due to the road unevenness. However, influences of vibration on Fuel Cell Stack have yet to be investigated completely. In this paper, the performance of a Fuel Cell Stack is experimentally studied in terms of gas-tightness, voltage degradation, AC impedance spectra, polarization curve and characteristic parameters in polarization curve through long-term strengthened road vibration tests, in order to investigate the influences of road-induced vibration on performance degradation of Fuel Cell Stack. The vibration tests are carried out on a six-channel multi axial simulation table with the vibration excitation spectra originally derived from the strengthened road of the ground prove. During the vibration test, several kinds of performance test including gas-tightness test, AC impedance diagnosis and polarization curve test are conducted at regular intervals. After the vibration test, the gas leakage rate of anode reaches 1.73 times of the initial value. The open circuit voltage and rated voltage decreases by 0.90% and 3.58%, respectively. Meanwhile, the performance of individual Cell voltage uniformity becomes worse distinctly. With the increase of vibration duration, the ohmic resistance obtained from AC impedance diagnosis ascends approximately linearly and presents a growth of 5.36% ultimately. An improved empirical Fuel Cell polarization curve model is adopted to fit the current–voltage data and estimate the characteristic parameters which decide the shape of polarization curve. It is noted that the limiting current density declines distinctly and the mass transfer loss increases mainly at the range of high current densities. The results indicate that the long-term strengthened road vibration condition exerts a significant influence on the durability of Fuel Cell Stack.
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AC impedance characteristics of a vehicle PEM Fuel Cell Stack under strengthened road vibrating conditions
International Journal of Hydrogen Energy, 2014Co-Authors: Yongping Hou, Xu Zhang, Dong HaoAbstract:Abstract Electrochemical impedance spectroscopy is used in this paper to investigate the performance of the Fuel Cell Stack and single Cells under long-term vibrating conditions on strengthened roads. During strengthened road vibration test, the electrochemical impedance spectra of Fuel Cell Stack and several Cells in the Stack are measured nine times at regular intervals. Parameters of a Randles-like equivalent circuit are fitted to the experimental data. The classical Randles Cell is extended by changing the standard plane capacitor into a constant phase element so that the quality of fit is improved. The results of the electrochemical impedance analysis indicate that the ohmic resistance of the Fuel Cell Stack is nearly linear with the vibration time and reaches a growth of 0.035695% per hour. While the charge transfer resistance of the Fuel Cell Stack during strengthened vibration test ascends after it falls down firstly, and finally tends to be stable. The influence of Cell position on the AC impedance is also studied, and the results of which show that the Cell position has a significant impact on the ohmic resistance.
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Experimental investigation of the steady-state efficiency of Fuel Cell Stack under strengthened road vibrating condition
International Journal of Hydrogen Energy, 2013Co-Authors: Yongping Hou, Dong Hao, Caoyuan Shen, Zhongying ShaoAbstract:Abstract The steady-state efficiency of the Fuel Cell Stack is experimentally investigated in terms of steady-state hydrogen utilization, actual efficiency and maximum efficiency point through a 162 h strengthened vibration test in this paper, in order to analyse the steady-state performance of the Fuel Cell Stack under long-term vibrating condition on strengthened roads. The load spectra applied in the test are simulated by the acceleration signals of the Fuel Cell Stack, which are previously measured in a vehicle vibration test. The load signals of the vehicle vibration test are iterated through a road simulator from vehicle acceleration signals which are originally sampled in the strengthened road of the ground prove. The test results show that the steady-state hydrogen utilization of the Stack decreases by 30.7% during the test. The maximum drop of steady-state actual efficiency is 21.0%. Additionally, the maximum efficiency point of the Stack declines by 5.4%, while the corresponding current experiences an increment of 47.2 A. From the results it can be concluded that the strengthened road vibration exerts a significant influence on the steady-state performance of the Fuel Cell Stack, which cannot and should not be ignored during the research.
Chih Kai Cheng - One of the best experts on this subject based on the ideXlab platform.
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Flexible five-in-one micro sensor for in-situ diagnosis of high-temperature proton exchange membrane Fuel Cell Stack
International Journal of Hydrogen Energy, 2015Co-Authors: Chi-yuan Lee, Yen-ting Cheng, Sheng Ming Chuang, Yen Pu Huang, Shuo-jen Lee, Fangbor Weng, Chih Kai ChengAbstract:During the chemical reaction process of high-temperature proton exchange membrane Fuel Cell (HT-PEMFC) Stack, the non-uniformity of internal local temperature, voltage, pressure, flow rate and current would result in poor membrane durability, Fuel distribution non-uniformity and adverse impact on the Fuel Cell Stack performance and service life. This study applies the micro-electromechanical systems (MEMS) technology to develop a flexible five-in-one micro sensor resistant to the high-temperature electrochemical environment. Six integrated micro sensors are embedded in the cathode field plate of HT-PEMFC Stack. At the operational temperature of 160 °C, current (5, 13, 20 A) and long term testing results suggest that the trends of the curves of the internal local temperature, voltage, pressure, flow rate and current density of the Fuel Cell Stack are considerably consistent, and the embedded flexible five-in-one micro sensors for in-situ diagnosis of Fuel Cell Stack have impact of about 1.3% on Fuel Cell Stack performance. The upstream temperature is higher than the downstream. The test result also shows that the heat distribution in the Fuel Cell Stack is nonuniform.
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Real-time Monitoring of Internal Temperature and Voltage of High-temperature Fuel Cell Stack
Electrochimica Acta, 2015Co-Authors: Chi-yuan Lee, Yen Pu Huang, Fangbor Weng, Chih-ping Chang, Chih Kai ChengAbstract:Abstract The nonuniform local temperature and voltage in the chemical reaction process of high-temperature proton exchange membrane Fuel Cell (HT-PEMFC) Stack can affect the reaction of membrane electrode assembly (MEA) and the performance and life of Fuel Cell Stack. The effectiveness and internal information of Fuel Cell Stack can be discussed by using external measurement, invasive, theoretical modeling, and single temperature, or voltage measurement. But there are some problems, such as mm scale sensor, inaccurate measurement, influencing the Fuel Cell Stack performance, and failing to know internal actual reactive state instantly. This study uses micro-electro-mechanical systems (MEMS) technology to develop a new generation flexible micro temperature and voltage sensors applicable to high-temperature electrochemical environment. Micro sensors have embedded in the cathode channel plate of HT-PEMFC Stack. At the operating temperature of 170 °C and constant current (2, 10, 20 A), the curvilinear trends of local temperature and voltage inside the Fuel Cell Stack measured by flexible micro sensors are consistent, proving the reliability of micro sensors. The test result also shows that the heat distribution in the Fuel Cell Stack is nonuniform.
Biao Zhou - One of the best experts on this subject based on the ideXlab platform.
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Diagnosis of PEM Fuel Cell Stack dynamic behaviors
Journal of Power Sources, 2008Co-Authors: Jixin Chen, Biao ZhouAbstract:In this study, the steady-state performance and dynamic behavior of a commercial 10-Cell Proton Exchange Membrane (PEM) Fuel Cell Stack was experimentally investigated using a self-developed PEM Fuel Cell test stand. The start-up characteristics of the Stack to different current loads and dynamic responses after current step-up to an elevated load were investigated. The Stack voltage was observed to experience oscillation at air excess coefficient of 2 due to the flooding/recovery cycle of part of the Cells. In order to correlate the Stack voltage with the pressure drop across the cathode/anode, fast Fourier transform was performed. Dominant frequency of pressure drop signal was obtained to indicate the water behavior in cathode/anode, thereby predicting the Stack voltage change. Such relationship between frequency of pressure drop and Stack voltage was found and summarized. This provides an innovative approach to utilize frequency of pressure drop signal as a diagnostic tool for PEM Fuel Cell Stack dynamic behaviors.
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liquid water transport in parallel serpentine channels with manifolds on cathode side of a pem Fuel Cell Stack
Journal of Power Sources, 2006Co-Authors: Kui Jiao, Biao Zhou, Peng QuanAbstract:Abstract Water management in a proton exchange membrane (PEM) Fuel Cell Stack has been a challenging issue on the road to commercialization. This paper presents a numerical investigation of air–water flow in parallel serpentine channels on cathode side of a PEM Fuel Cell Stack by use of the commercial Computational Fluid Dynamics (CFD) software package FLUENT. Different air–water flow behaviours inside the serpentine flow channels with inlet and outlet manifolds were discussed. The results showed that there were significant variations of water distribution and pressure drop in different Cells at different times. The “collecting-and-separating effect” due to the serpentine shape of the gas flow channels, the pressure drop change due to the water distribution inside the inlet and outlet manifolds were observed. Several gas flow problems of this type of parallel serpentine channels were identified and useful suggestions were given through investigating the flow patterns inside the channels and manifolds.
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water and thermal management for ballard pem Fuel Cell Stack
Journal of Power Sources, 2005Co-Authors: Xiaochen Yu, Biao Zhou, Andrzej SobiesiakAbstract:A water and thermal management model for a Ballard PEM Fuel Cell Stack was developed to investigate its performance. A general calculation methodology was developed to implement this model. Knowing a set of gas feeding conditions (i.e., pressure, temperature, flow rate) and Stack physical conditions (i.e., channel geometry, heat transfer coefficients, operating current), the model could provide information regarding the reaction products (i.e., water and heat), Stack power, Stack temperature, and system efficiency, thereby assisting the designer in achieving the best thermal and water management. Furthermore, if the Stack undergoes a perturbation, such as the initial start-up, quick change in current, or a shutdown, the model could predict the dynamic information regarding Stack temperature, Cell voltage, and power as a function of time.
Chi-yuan Lee - One of the best experts on this subject based on the ideXlab platform.
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Flexible five-in-one micro sensor for in-situ diagnosis of high-temperature proton exchange membrane Fuel Cell Stack
International Journal of Hydrogen Energy, 2015Co-Authors: Chi-yuan Lee, Yen-ting Cheng, Sheng Ming Chuang, Yen Pu Huang, Shuo-jen Lee, Fangbor Weng, Chih Kai ChengAbstract:During the chemical reaction process of high-temperature proton exchange membrane Fuel Cell (HT-PEMFC) Stack, the non-uniformity of internal local temperature, voltage, pressure, flow rate and current would result in poor membrane durability, Fuel distribution non-uniformity and adverse impact on the Fuel Cell Stack performance and service life. This study applies the micro-electromechanical systems (MEMS) technology to develop a flexible five-in-one micro sensor resistant to the high-temperature electrochemical environment. Six integrated micro sensors are embedded in the cathode field plate of HT-PEMFC Stack. At the operational temperature of 160 °C, current (5, 13, 20 A) and long term testing results suggest that the trends of the curves of the internal local temperature, voltage, pressure, flow rate and current density of the Fuel Cell Stack are considerably consistent, and the embedded flexible five-in-one micro sensors for in-situ diagnosis of Fuel Cell Stack have impact of about 1.3% on Fuel Cell Stack performance. The upstream temperature is higher than the downstream. The test result also shows that the heat distribution in the Fuel Cell Stack is nonuniform.
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Real-time Monitoring of Internal Temperature and Voltage of High-temperature Fuel Cell Stack
Electrochimica Acta, 2015Co-Authors: Chi-yuan Lee, Yen Pu Huang, Fangbor Weng, Chih-ping Chang, Chih Kai ChengAbstract:Abstract The nonuniform local temperature and voltage in the chemical reaction process of high-temperature proton exchange membrane Fuel Cell (HT-PEMFC) Stack can affect the reaction of membrane electrode assembly (MEA) and the performance and life of Fuel Cell Stack. The effectiveness and internal information of Fuel Cell Stack can be discussed by using external measurement, invasive, theoretical modeling, and single temperature, or voltage measurement. But there are some problems, such as mm scale sensor, inaccurate measurement, influencing the Fuel Cell Stack performance, and failing to know internal actual reactive state instantly. This study uses micro-electro-mechanical systems (MEMS) technology to develop a new generation flexible micro temperature and voltage sensors applicable to high-temperature electrochemical environment. Micro sensors have embedded in the cathode channel plate of HT-PEMFC Stack. At the operating temperature of 170 °C and constant current (2, 10, 20 A), the curvilinear trends of local temperature and voltage inside the Fuel Cell Stack measured by flexible micro sensors are consistent, proving the reliability of micro sensors. The test result also shows that the heat distribution in the Fuel Cell Stack is nonuniform.
