Design, Fabrication, and Performance Analysis of a Passive Micro-PEM-Fuel-Cell Stack

2009 ◽  
Vol 6 (3) ◽  
Author(s):  
Fang-Bor Weng ◽  
Bo-Shian Jou ◽  
Pei-Hung Chi ◽  
Ay Su ◽  
Shih Hung Chan
Keyword(s):  
Fuel Cell ◽  
Flow Rate ◽  
Low Voltage ◽  
Cell System ◽  
Membrane Electrode ◽  
Hydrogen Flow Rate ◽  
High Hydrogen ◽  
Current Output ◽  
Fuel Cell Stack ◽  
Hydrogen Flow

A micro-fuel-cell stack of six cells with an active area of 2.73 cm2 and 2.5 W output power has been designed and fabricated in-house. It can go with mini hydrogen storage and provide enough power for portable electric products. Under polarization curve measurement, when the voltage was scanning to low voltage, the performance was quickly decayed by the low fuel concentration. This result was contributed by a limited fuel supply of metal hydride hydrogen tank. The voltage declined to very low voltage in some of the cell stacks when the current output was at high current. This phenomenon is attributed to the self-breath of air in the cathode. At the higher current of 0.9 A condition, the stack voltage was decreased even though the high hydrogen flow rate was increased. The solution to prevent the decrease in voltage is adding the airflow in the cathode. The fuel cell performances respond to the transient of load changes influenced by the hydrogen flow rate and step increase in current. The flow change can decrease the high resistance in the transient of the current output, which prevents membrane electrode assembly (MEA) degradation caused by being operated for many times. After a series of experiments in this study, the micro-fuel-cell system demonstrates the ability of offering a stable power to a cell phone or robot with reliability.

scholarly journals Sliding Mode Control for Stabilizing of Boost Converter in a Solid Oxide Fuel Cell

2013 ◽  
Vol 13 (4) ◽  
pp. 139-147 ◽  
Author(s):  
Junsheng Jiao
Keyword(s):  
Fuel Cell ◽  
Sliding Mode Control ◽  
Flow Rate ◽  
Output Voltage ◽  
Sliding Mode ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Hydrogen Flow Rate ◽  
Dc Voltage ◽  
Hydrogen Flow

Abstract The output voltage of Solid Oxide Fuel Cell (SOFC) is usually changed with the temperature and hydrogen flow rate. Since the fuel cell can generate a wide range of voltages and currents at the terminals, as a consequence, a constant DC voltage and function cannot be maintained by itself as a DC voltage power supply source. To solve this problem, a simple SOFC electrochemical model is introduced to control the output voltage. The Sliding Mode Control (SMC) is used to control the output voltage of the DC-DC converter for maintaining the constant DC voltage when the temperature and hydrogen flow rate are changed. By the simulation results it can be seen that the SMC technique has improved the transient response and reduced the steady state error of DC voltage.

Performance of a Thermally Coupled Hydrogen Storage and Fuel Cell System Under Different Operation Conditions

2016 ◽  
Vol 13 (2) ◽  
Author(s):  
Gustavo A. Andreasen ◽  
Silvina G. Ramos ◽  
Hernán A. Peretti ◽  
Walter E. Triaca
Keyword(s):  
Fuel Cell ◽  
Hydrogen Storage ◽  
Metal Hydride ◽  
Cell System ◽  
Proton Exchange ◽  
Integrated System ◽  
Equilibrium Pressure ◽  
High Hydrogen ◽  
Hydrogen Flow ◽  
Operation Conditions

The performance of a hydrogen storage prototype loaded with AB5H6 hydride, whose equilibrium pressure makes it suitable for both feeding a H2/air proton exchange membrane (PEM) fuel cell and being charged directly from a low-pressure water electrolyzer, interacting thermally with the fuel cell exhaust air, is reported. The nominal 70 L hydrogen storage capacity of the prototype suffices for hydrogen delivery at 0.5 L min−1, which allows a power supply of 50 W for 140 min from the H2/air fuel cell in the absence of thermal interaction. The storage prototype was characterized by monitoring the internal pressure and the temperatures of the external wall and at the center inside the container at different hydrogen discharge conditions. The responses of the integrated system after either immersing the metal hydride container in air or exposing it to the fuel cell hot exhaust air stream under forced convection were compared. The system shows the best performance when the heat generated at the fuel cell is used to increase the metal hydride container temperature, allowing the operation of the fuel cell at 280 W for 16 min at a high hydrogen flow rate of 4 L min−1.

Amorphous-to-nanocrystalline transition in silicon thin films by hydrogen diluted silane using PE-CVD method

2020 ◽  
Vol 13 ◽  
Author(s):  
Ashok Jadhavar ◽  
Vidya Doiphode ◽  
Ajinkya Bhorde ◽  
Yogesh Hase ◽  
Pratibha Shinde ◽  
...  
Keyword(s):  
Flow Rate ◽  
Volume Fraction ◽  
Defect Density ◽  
Hydrogen Flow Rate ◽  
Spectroscopy Analysis ◽  
Deposition Parameter ◽  
Hydrogen Flow ◽  
Cvd Method ◽  
Silicon Thin Films ◽  
Increasing Trend

: Herein, we report effect of variation of hydrogen flow rate on properties of Si:H films synthesized using PE-CVD method. Raman spectroscopy analysis show increase in crystalline volume fraction and crystallite size implying that hydrogen flow in PECVD promote the growth of crystallinity in nc-Si:H films with an expense of reduction in deposition rate. FTIR spectroscopy analysis indicates that hydrogen content in the film increases with increase in hydrogen flow rate and hydrogen is predominantly incorporated in Si-H2 and (Si-H2)n bonding configuration. The optical band gap determined using E04 method and Tauc method (ETauc) show increasing trend with increase in hydrogen flow rate and E04 is found higher than ETauc over the entire range of hydrogen flow rate studied. We also found that the defect density and Urbach energy also increases with increase in hydrogen flow rate. Photosensitivity (Photo /Dark) decreases from  103 to  1 when hydrogen flow rate increased from 30 sccm to 100 sccm and can attributed to amorphous-to-nanocrystallization transition in Si:H films. The results obtained from the present study demonstrated that hydrogen flow rate is an important deposition parameter in PE-CVD to synthesize nc-Si:H films.

Exergy Analysis of a Hybrid Micro Gas Turbine Fuel Cell System Based on Existing Components

2012 ◽  
Author(s):  
D. P. Bakalis ◽  
A. G. Stamatis
Keyword(s):  
Fuel Cell ◽  
Hybrid System ◽  
Exergy Analysis ◽  
Cell System ◽  
System Component ◽  
Utilization Factor ◽  
Fuel Cell Stack ◽  
Micro Gas Turbine ◽  
Partial Load ◽  
Set Up

A hybrid system based on an existing recuperated microturbine and a pre-commercially available high temperature tubular solid oxide fuel cell is modeled in order to study its performance. Individual models are developed for the microturbine and fuel cell generator and merged into a single one in order to set up the hybrid system. The model utilizes performance maps for the compressor and turbine components for the part load operation. The full and partial load exergetic performance is studied and the amounts of exergy destruction and efficiency of each hybrid system component are presented, in order to evaluate the irreversibilities and thermodynamic inefficiencies. Moreover, the effects of various performance parameters such as fuel cell stack temperature and fuel utilization factor are investigated. Based on the available results, suggestions are given in order to reduce the overall system irreversibility. Finally, the environmental impact of the hybrid system operation is evaluated.

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