scholarly journals Finite Time Thermodynamic Optimization of an Irreversible Proton Exchange Membrane Fuel Cell for Vehicle Use

Processes ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 419 ◽  
Author(s):  
Changjie Li ◽  
Ye Liu ◽  
Bing Xu ◽  
Zheshu Ma
Keyword(s):  
Power Density ◽  
Output Power ◽  
Proton Exchange Membrane ◽  
Operating Temperature ◽  
Maximum Output Power ◽  
Proton Exchange ◽  
Maximum Output ◽  
Operating Pressure ◽  
Output Efficiency ◽  
Exchange Membrane

A finite time thermodynamic model of an irreversible proton exchange membrane fuel cell (PEMFC) for vehicle use was established considering the effects of polarization losses and leakage current. Effects of operating parameters, including operating temperature, operating pressure, proton exchange membrane water content, and proton exchange membrane thickness, on the optimal performance of the irreversible PEMFC are numerically studied in detail. When the operating temperature of the PEMFC increases, the optimal performances of PEMFC including output power density, output efficiency, ecological objective function, and ecological coefficient of performance, will be improved. Among them, the optimal ecological objective function increased by 81%. The proton film thickness has little effect on the output efficiency and the ecological of coefficient performance. The maximum output power density increased by 58% as the water content of the proton exchange membrane increased from 50% to the saturation point. The maximum output power density increases with the operating pressure.

scholarly journals Ecological Performance Optimization of a High Temperature Proton Exchange Membrane Fuel Cell

Mathematics ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1332
Author(s):  
Dongxu Li ◽  
Siwei Li ◽  
Zheshu Ma ◽  
Bing Xu ◽  
Zhanghao Lu ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
High Temperature ◽  
Power Density ◽  
Proton Exchange Membrane ◽  
Operating Temperature ◽  
Proton Exchange ◽  
Maximum Power ◽  
Operating Pressure ◽  
Maximum Power Density ◽  
Exchange Membrane

According to finite-time thermodynamics, an irreversible high temperature proton exchange membrane fuel cell (HT-PEMFC) model is established, and the mathematical expressions of the output power, energy efficiency, exergy efficiency and ecological coefficient of performance (ECOP) of HT-PEMFC are deduced. The ECOP is a step forward in optimizing the relationship between power and power dissipation, which is more in line with the principle of ecology. Based on the established HT-PEMFC model, the maximum power density is obtained under different parameters that include operating temperature, operating pressure, phosphoric acid doping level and relative humidity. At the same time, the energy efficiency, exergy efficiency and ECOP corresponding to the maximum power density are acquired so as to determine the optimal value of each index under the maximum power density. The results show that the higher the operating temperature and the doping level, the better the performance of HT-PEMFC is. However, the increase of operating pressure and relative humidity has little effect on HT-PEMFC performance.

Analysis of Voltage Losses in High Temperature Proton Exchange Membrane Fuel Cells with Properties of Membrane Materials and Fluent Software

2012 ◽  
Vol 625 ◽  
pp. 235-238 ◽  
Author(s):  
Xiao Le Yang ◽  
Yan Yin ◽  
Bin Jia ◽  
Qing Du
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Reasonable Agreement ◽  
Proton Exchange Membrane ◽  
Operating Temperature ◽  
Proton Exchange ◽  
Operating Pressure ◽  
Ohmic Losses ◽  
Fluent Software ◽  
Exchange Membrane

The mass and charge transport significantly affect the performance of fuel cells. A numerical model of high temperature proton exchange membrane fuel cells is developed. Ohmic losses and activation losses of both anode and cathode are analyzed at different design and operating condition. The polarization curve predicted by the model is in a reasonable agreement with published experimental data. The results of the model indicate that increasing the phosphoric acid doping level or operating temperature is helpful to decrease ohmic losses. The operating temperature has negligible impact on activation losses. Increasing the operating pressure can decrease activation losses.

scholarly journals Synthesis of nano-carbon by in-liquid plasma method and its application to a support material of Pt catalyst for fuel cell

2019 ◽  
Vol 9 ◽  
pp. 184798041985315 ◽  
Author(s):  
Abdulrahman Alsaeedi ◽  
Yoshiyuki Show
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Maximum Output Power ◽  
Proton Exchange ◽  
Pt Catalyst ◽  
Maximum Output ◽  
Support Material ◽  
Transmission Electron ◽  
Nano Carbon ◽  
Exchange Membrane

One of the applications of nano-carbon is a support material of platinum (Pt) catalyst for fuel cells. In this study, the nano-carbon was successfully synthesized by in-liquid plasma in ethanol. The synthesized nano-carbon was characterized by the transmission electron microscope and the Raman spectroscopy. Moreover, the nano-carbon was applied to a support material of Pt catalyst for a proton exchange membrane fuel cell. The formation of the Pt particles on the nano-carbon was also carried out using the in-liquid plasma. The formed Pt/nano-carbon worked as a catalyst of the fuel cell. The fuel cell, fabricated with the Pt/nano-carbon catalyst, generated the maximum output power of 580 mW.

Optimum Design and Performance Simulation of a Multi-device Integrated System Based on a Proton Exchange Membrane Fuel Cell

2022 ◽  
pp. 1-33
Author(s):  
Xiuqin Zhang ◽  
Wentao Cheng ◽  
Qiubao Lin ◽  
Longquan Wu ◽  
Junyi Wang ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Power Density ◽  
Power Output ◽  
Proton Exchange Membrane ◽  
Waste Heat ◽  
Proton Exchange ◽  
Integrated System ◽  
Interior Space ◽  
And Performance ◽  
Exchange Membrane

Abstract Proton exchange membrane fuel cells (PEMFCs) based on syngas are a promising technology for electric vehicle applications. To increase the fuel conversion efficiency, the low-temperature waste heat from the PEMFC is absorbed by a refrigerator. The absorption refrigerator provides cool air for the interior space of the vehicle. Between finishing the steam reforming reaction and flowing into the fuel cell, the gases release heat continuously. A Brayton engine is introduced to absorb heat and provide a useful power output. A novel thermodynamic model of the integrated system of the PEMFC, refrigerator, and Brayton engine is established. Expressions for the power output and efficiency of the integrated system are derived. The effects of some key parameters are discussed in detail to attain optimum performance of the integrated system. The simulation results show that when the syngas consumption rate is 4.0 × 10−5 mol s−1cm−2, the integrated system operates in an optimum state, and the product of the efficiency and power density reaches a maximum. In this case, the efficiency and power density of the integrated system are 0.28 and 0.96 J s−1 cm−2, respectively, which are 46% higher than those of a PEMFC.

The Effect of Inlet Parameters on Fluid Flow and Cell Performance at Cathode of a Proton Exchange Membrane Fuel Cell

2010 ◽  
Vol 7 (4) ◽  
Author(s):  
Utku Gulan ◽  
Hasmet Turkoglu ◽  
Irfan Ar
Keyword(s):  
Reynolds Number ◽  
Fuel Cell ◽  
Power Density ◽  
Current Density ◽  
Proton Exchange Membrane ◽  
Catalyst Layer ◽  
Pem Fuel Cell ◽  
Proton Exchange ◽  
Exchange Membrane ◽  
Oxygen Mole Fraction

In this study, the fluid flow and cell performance in cathode side of a proton exchange membrane (PEM) fuel cell were numerically analyzed. The problem domain consists of cathode gas channel, cathode gas diffusion layer, and cathode catalyst layer. The equations governing the motion of air, concentration of oxygen, and electrochemical reactions were numerically solved. A computer program was developed based on control volume method and SIMPLE algorithm. The mathematical model and program developed were tested by comparing the results of numerical simulations with the results from literature. Simulations were performed for different values of inlet Reynolds number and inlet oxygen mole fraction at different operation temperatures. Using the results of these simulations, the effects of these parameters on the flow, oxygen concentration distribution, current density and power density were analyzed. The simulations showed that the oxygen concentration in the catalyst layer increases with increasing Reynolds number and hence the current density and power density of the PEM fuel cell also increases. Analysis of the data obtained from simulations also shows that current density and power density of the PEM fuel cell increases with increasing operation temperature. It is also observed that increasing the inlet oxygen mole fraction increases the current density and power density.

scholarly journals Preparation and Study of Sulfonated Co-Polynaphthoyleneimide Proton-Exchange Membrane for a H2/Air Fuel Cell

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5297
Author(s):  
Ulyana M. Zavorotnaya ◽  
Igor I. Ponomarev ◽  
Yulia A. Volkova ◽  
Alexander D. Modestov ◽  
Vladimir N. Andreev ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Proton Exchange Membrane ◽  
Maximum Output Power ◽  
Exchange Capacity ◽  
Proton Exchange ◽  
Molar Ratio ◽  
Disulfonic Acid ◽  
Membrane Electrode ◽  
Maximum Output ◽  
Practical Applications

The sulfonated polynaphthoyleneimide polymer (co-PNIS70/30) was prepared by copolymerization of 4,4′-diaminodiphenyl ether-2,2′-disulfonic acid (ODAS) and 4,4’-methylenebisanthranilic acid (MDAC) with ODAS/MDAC molar ratio 0.7/0.3. High molecular weight co-PNIS70/30 polymers were synthesized either in phenol or in DMSO by catalytic polyheterocyclization in the presence of benzoic acid and triethylamine. The titration reveals the ion-exchange capacity of the polymer equal to 2.13 meq/g. The membrane films were prepared by casting polymer solution. Conductivities of the polymer films were determined using both in- and through-plane geometries and reached ~96 and ~60 mS/cm, respectively. The anisotropy of the conductivity is ascribed to high hydration of the surface layer compared to the bulk. SFG NMR diffusometry shows that, in the temperature range from 213 to 353 K, the 1H self-diffusion coefficient of the co-PNIS70/30 membrane is about one third of the diffusion coefficient of Nafion® at the same humidity. However, temperature dependences of proton conductivities of Nafion® and of co-PNIS70/30 membranes are nearly identical. Membrane–electrode assemblies (MEAs) based on co-PNIS70/30 were fabricated by different procedures. The optimal MEAs with co-PNIS70/30 membranes are characterized by maximum output power of ~370 mW/cm2 at 80 °C. It allows considering sulfonated co-PNIS70/30 polynaphthoyleneimides membrane attractive for practical applications.

Development of a 600 W Proton Exchange Membrane Fuel Cell Power System for the Hazardous Mission Robot

2010 ◽  
Vol 7 (3) ◽  
Author(s):  
Sang-Yeop Lee ◽  
In-Gyu Min ◽  
Hyoung-Juhn Kim ◽  
Suk Woo Nam ◽  
Jaeyoung Lee ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Power System ◽  
Power Density ◽  
Proton Exchange Membrane ◽  
Hybrid Control ◽  
Operation Time ◽  
Proton Exchange ◽  
Power Sources ◽  
Start Up ◽  
Exchange Membrane

Due to the advantage of fuel cells over secondary batteries such as long operation time, many efforts were executed in order to use fuel cells as main power sources of small electronic devices such as laptop computers and mobile phones. For the same reason, fuel cells are promising power sources for the hazardous mission robots. Fuel cells are able to increase their radius action through extension of operation time. Despite this advantage, there still exist technical barriers such as increasing power density, efficient hydrogen storage, and fast startup of the power system. First, in order to increase power density, the united stack including proton exchange membrane fuel cells (PEMFC) and membrane humidifying cells were developed. Also, the hydrogen generating system using NaBH4 solution was employed to store hydrogen effectively. In addition, to shorten start-up time, hybrid control of PEMFC and Li-ion battery was adopted. The approaches mentioned above were evaluated. The developed PEMFC/humidifier stack showed high performance. As compared with full humidification condition by external humidifiers, the performance decrease was only 1% even though hydrogen was not humidified and air was partially humidified. Besides, by integrating the PEMFC and the humidifier into a single stack, considerable space for tubing between them was saved. Also, the hydrogen generator operated well with the PEMFC system and allowed for effective fuel storing and refueling. In addition, due to the efficient hybrid control of PEMFC and battery, start-up time was significantly shortened and capacity of PEMFC was reduced, resulting in compactness of the power system. In conclusion, a 600 W PEMFC power system was developed and successfully operated with the robot. Through development and evaluation of the PEMFC power system, the possibility of PEMFC as a novel power source for the hazardous mission robot was verified.

4H-SiC Planar MESFETs on High-Purity Semi-Insulating Substrates

2007 ◽  
Vol 556-557 ◽  
pp. 763-766 ◽  
Author(s):  
Jeong Hyuk Yim ◽  
Ho Keun Song ◽  
Jeong Hyun Moon ◽  
Han Seok Seo ◽  
Jong Ho Lee ◽  
...  
Keyword(s):  
Power Density ◽  
Output Power ◽  
High Purity ◽  
Maximum Output Power ◽  
Drain Current ◽  
Maximum Output ◽  
Power Gain ◽  
Si Substrates ◽  
Class A ◽  
Current Instability

Planar MESFETs were fabricated on high-purity semi-insulating (HPSI) 4H-SiC substrates. The saturation drain current of the fabricated MESFETs with a gate length of 0.5 μm and a gate width of 100 μm was 430 mA/mm, and the transconductance was 25 mS/mm. The maximum oscillation frequency and cut-off frequency were 26.4 GHz and 7.2 GHz, respectively. The power gain was 8.4 dB and the maximum output power density was 2.8 W/mm for operation of class A at CW 2 GHz. MESFETs on HPSI substrates showed no current instability and much higher output power density in comparison to MESFETs on vanadium-doped SI substrates.

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