Research

16 pages, 3638 KiB

Open AccessArticle

Anode Nitrogen Concentration Estimation Based on Voltage Variation Characteristics for Proton Exchange Membrane Fuel Cell Stacks

by Ruifeng Guo, Dongfang Chen, Yuehua Li, Wenlong Wu, Song Hu and Xiaoming Xu

Energies 2023, 16(5), 2111; https://0-doi-org.brum.beds.ac.uk/10.3390/en16052111 - 22 Feb 2023

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Abstract

Hydrogen energy has become an important way to solve energy crises owing to its non-pollution, high level of efficiency, and wide application. Proton exchange membrane fuel cells (PEMFCs) have received wide attention as an energy conversion device for hydrogen energy. The hydrogen concentration [...] Read more.

Hydrogen energy has become an important way to solve energy crises owing to its non-pollution, high level of efficiency, and wide application. Proton exchange membrane fuel cells (PEMFCs) have received wide attention as an energy conversion device for hydrogen energy. The hydrogen concentration in the PEMFC anode directly determines the output voltage of the stack. The performance of the PEMFC gradually decreases due to the accumulation of nitrogen. However, the continuous circulation of anode gas and the nitrogen accumulation at the anode due to transmembrane diffusion lead to difficulties in estimating the anode gas concentration. The relationship between anode nitrogen concentration and voltage variation characteristics was studied by increasing the anode hydrogen concentration through the method of increasing nitrogen concentration and conducting experiments on a 16-cell stack. In this paper, an estimation method for nitrogen concentration in the anode is proposed to evaluate the nitrogen concentration in the anode on the basis of voltage variation characteristics, and the method was recalibrated and validated using experimental data. Due to the inhomogeneity of the gas distribution within the PEMFC stack, the mean cell voltage can provide a more accurate estimation of the anode nitrogen concentration compared to a single cell voltage. It is shown that the proposed approach can offer a new method to estimate anode nitrogen concentration. Compared with the conventional method, the new method is simpler as it does not require additional equipment or complex algorithms. In this paper, the anode nitrogen concentration was estimated by applying this method with a maximum error of only 0.35%. Full article

(This article belongs to the Special Issue Design, Testing and Fault Diagnosis for Fuel Cells)

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17 pages, 2122 KiB

Open AccessArticle

Kinetics of Oxygen Reduction Reaction of Polymer-Coated MWCNT-Supported Pt-Based Electrocatalysts for High-Temperature PEM Fuel Cell

by Md Ahsanul Haque, Md Mahbubur Rahman, Faridul Islam, Abu Bakar Sulong, Loh Kee Shyuan, Ros emilia Rosli, Ashok Kumar Chakraborty and Julfikar Haider

Energies 2023, 16(3), 1537; https://0-doi-org.brum.beds.ac.uk/10.3390/en16031537 - 03 Feb 2023

Cited by 1 | Viewed by 2046

Abstract

Sluggish oxygen reduction reaction (ORR) of electrodes is one of the main challenges in fuel cell systems. This study explored the kinetics of the ORR reaction mechanism, which enables us to understand clearly the electrochemical activity of the electrode. In this research, electrocatalysts [...] Read more.

Sluggish oxygen reduction reaction (ORR) of electrodes is one of the main challenges in fuel cell systems. This study explored the kinetics of the ORR reaction mechanism, which enables us to understand clearly the electrochemical activity of the electrode. In this research, electrocatalysts were synthesized from platinum (Pt) catalyst with multi-walled carbon nanotubes (MWCNTs) coated by three polymers (polybenzimidazole (PBI), sulfonated tetrafluoroethylene (Nafion), and polytetrafluoroethylene (PTFE)) as the supporting materials by the polyol method while hexachloroplatinic acid (H₂PtCl₆) was used as a catalyst precursor. The oxygen reduction current of the synthesized electrocatalysts increased that endorsed by linear sweep voltammetry (LSV) curves while increasing the rotation rates of the disk electrode. Additionally, MWCNT-PBI-Pt was attributed to the maximum oxygen reduction current densities at −1.45 mA/cm² while the minimum oxygen reduction current densities of MWCNT-Pt were obtained at −0.96 mAcm². However, the ring current densities increased steadily from potential 0.6 V to 0.0 V due to their encounter with the hydrogen peroxide species generated by the oxygen reduction reactions. The kinetic limiting current densities (J_K) increased gradually with the applied potential from 1.0 V to 0.0 V. It recommends that the ORR consists of a single step that refers to the first-order reaction. In addition, modified MWCNT-supported Pt electrocatalysts exhibited high electrochemically active surface areas (ECSA) at 24.31 m²/g of MWCNT-PBI-Pt, 22.48 m²/g of MWCNT-Nafion-Pt, and 20.85 m²/g of MWCNT-PTFE-Pt, compared to pristine MWCNT-Pt (17.66 m²/g). Therefore, it can be concluded that the additional ionomer phase conducting the ionic species to oxygen reduction in the catalyst layer could be favorable for the ORR reaction. Full article

(This article belongs to the Special Issue Design, Testing and Fault Diagnosis for Fuel Cells)

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22 pages, 5875 KiB

Open AccessArticle

Numerical Investigation on Internal Structures of Ultra-Thin Heat Pipes for PEM Fuel Cells Cooling

by Yuqi Han, Weilin Zhuge, Jie Peng, Yuping Qian and Yangjun Zhang

Energies 2023, 16(3), 1023; https://0-doi-org.brum.beds.ac.uk/10.3390/en16031023 - 17 Jan 2023

Viewed by 1239

Abstract

Proton exchange membrane fuel cell (PEMFC) powered propulsion has gained increasing attention in urban air mobility applications in recent years. Due to its high power density, ultra-thin heat pipe technology has great potential for cooling PEMFCs, but optimizing the limited internal cavity of [...] Read more.

Proton exchange membrane fuel cell (PEMFC) powered propulsion has gained increasing attention in urban air mobility applications in recent years. Due to its high power density, ultra-thin heat pipe technology has great potential for cooling PEMFCs, but optimizing the limited internal cavity of the heat pipe remains a significant challenge. In this study, a three-dimensional multiphase model of the heat pipe cooled PEMFC is built to evaluate the impact of three internal structures, layered, spaced, and composite, of ultra-thin heat pipes on system performance. The results show that the heat pipe cooling with the composite structure yields a lower thermal resistance and a larger operating range for the PEMFC system compared to other internal structures because of more rational layout of the internal cavity. In addition, the relationship between land to channel width ratio (LCWR) and local transport property is analyzed and discussed based on composite structural heat pipes. The heat pipe cooled PEMFC with a LCWR of 0.75 has a significant advantage in limiting current density and maximum power density compared to the LCWRs of 1 and 1.33 as a result of more uniform in-plane distributions of temperature and liquid water within its cathode catalyst layer. Full article

(This article belongs to the Special Issue Design, Testing and Fault Diagnosis for Fuel Cells)

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15 pages, 5871 KiB

Open AccessArticle

Powder Bed Fusion 3D Printing and Performance of Stainless-Steel Bipolar Plate with Rectangular Microchannels and Microribs

by Chul Kyu Jin, Jae Hyun Kim and Bong-Seop Lee

Energies 2022, 15(22), 8463; https://0-doi-org.brum.beds.ac.uk/10.3390/en15228463 - 12 Nov 2022

Cited by 1 | Viewed by 1745

Abstract

For the high performance of a fuel cell where a bipolar plate (BP) is applied, rectangular channel, microchannel width, micro-rib, enough channel quantity, adequate channel depth, and innovative flow field design should be realized from a configuration standpoint. In this study, a stainless-steel [...] Read more.

For the high performance of a fuel cell where a bipolar plate (BP) is applied, rectangular channel, microchannel width, micro-rib, enough channel quantity, adequate channel depth, and innovative flow field design should be realized from a configuration standpoint. In this study, a stainless-steel BP with a microchannel flow field is fabricated with a powder bed fusion (PBF) 3D printer to improve fuel cell performance. A BP with a triple serpentine flow field, rectangular channel, 300 μm channel width, 300 μm rib, and 500 μm channel depth is designed. The print is completed perfectly until the flow field. The bending phenomenon due to thermal deformation does not occur in the BP fabricated by designing the thickness at 2 mm. Performance tests are conducted using fabricated stainless-steel BPs. The current density value is 1.2052 A/cm² at 0.6 V. This value is higher by 52.8% than the BP with 940 μm channels (rectangle, 940 μm ribs, and 500 μm channel depth). In addition, the value is higher by 24.9% than a graphite BP with 940 μm channels (rectangle, 940 μm ribs, and 1000 μm channel depth). The current density values are measured at 0.6 V for 260 h. Full article

(This article belongs to the Special Issue Design, Testing and Fault Diagnosis for Fuel Cells)

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20 pages, 3280 KiB

Open AccessArticle

Modeling and Experimental Investigation of the Anode Inlet Relative Humidity Effect on a PEM Fuel Cell

by Lu Zhang, Yongfeng Liu, Guijun Bi, Xintong Liu, Long Wang, Yuan Wan and Hua Sun

Energies 2022, 15(13), 4532; https://0-doi-org.brum.beds.ac.uk/10.3390/en15134532 - 21 Jun 2022

Cited by 1 | Viewed by 1629

Abstract

External humidification has been used as a flexible water management strategy for the proton exchange membrane fuel cell (PEMFC). To study the anode inlet relative humidity (ARH) effect on the performance of PEMFC, the anode inlet water content (AIWC) model is established, including [...] Read more.

External humidification has been used as a flexible water management strategy for the proton exchange membrane fuel cell (PEMFC). To study the anode inlet relative humidity (ARH) effect on the performance of PEMFC, the anode inlet water content (AIWC) model is established, including condensation rates and water activity. A comparable analysis between the AIWC model, Fluent model and experiment is conducted at 60 °C operating temperature, four different anode relative humidities (25%, 50%, 75% and 100%), and 100% cathode relative humidity (CRH). The species distributions of water content and hydrogen concentration are presented and analyzed. The results show the relative error of the voltage results derived from the AIWC model has been reduced by 3.2% (the original is 4.6% in the Fluent model) especially at 240 mA·cm⁻² for 50% ARH. An increase in hydrogen humidity can improve the PEMFC output at low ARH (25% and 50%). Meanwhile, at high ARH (100%), the excess water produced does not play a positive role. At 50% ARH, the water content and hydrogen distribution are more uniform all over the anode channels. Full article

(This article belongs to the Special Issue Design, Testing and Fault Diagnosis for Fuel Cells)

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20 pages, 2478 KiB

Open AccessArticle

Variation Characteristic Analysis of Water Content at the Flow Channel of Proton Exchange Membrane Fuel Cell

by Lu Zhang, Yongfeng Liu, Pucheng Pei, Xintong Liu, Long Wang and Yuan Wan

Energies 2022, 15(9), 3280; https://0-doi-org.brum.beds.ac.uk/10.3390/en15093280 - 29 Apr 2022

Cited by 3 | Viewed by 1650

Abstract

The performance of proton exchange membrane fuel cells (PEMFCs) is directly affected by the nonlinear variations in water content. To study the variation in water content and its effect on PEMFC performance, the water condensation rate (WCR) model is established, which determines the [...] Read more.

The performance of proton exchange membrane fuel cells (PEMFCs) is directly affected by the nonlinear variations in water content. To study the variation in water content and its effect on PEMFC performance, the water condensation rate (WCR) model is established, which determines the proportional relationship between evaporation and condensation rates in terms of the switch function, and the two-phase flow evolution and pressure drop are considered as well. The WCR model is imported into Fluent software through a user-defined function for simulation, and the test system is established under different operating conditions. Then, the contours of H₂O molar concentrations and polarization curves are analyzed and compared. The results show that the condensation rate value of the cathode channel is from 1.05 to 1.55 times higher than that of the anode channel. The WCR model can predict the variation in water content and improve the accuracy of the performance calculation by from 9% to 31%. The accuracy of the WCR model is especially improved, by 31%, at high current densities compared with the Fluent model when the inlet pressure is 30 kPa. Full article

(This article belongs to the Special Issue Design, Testing and Fault Diagnosis for Fuel Cells)

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13 pages, 2677 KiB

Open AccessArticle

Study on Anode Catalyst Layer Configuration for Proton Exchange Membrane Fuel Cell with Enhanced Reversal Tolerance and Polarization Performance

by Xia Sheng, Chunyu Ru, Honghui Zhao, Shouyi Jin, Bowen Wang, Yupeng Wang, Linghai Han and Kui Jiao

Energies 2022, 15(8), 2732; https://0-doi-org.brum.beds.ac.uk/10.3390/en15082732 - 08 Apr 2022

Viewed by 1801

Abstract

Hydrogen starvation leads to the extreme deterioration of fuel cell performance due to the induced voltage reversal and carbon corrosion in the anode catalyst layer (ACL) and gas diffusion layer. In this paper, reversal-tolerant anodes (RTAs) with different ACL configurations are proposed, where [...] Read more.

Hydrogen starvation leads to the extreme deterioration of fuel cell performance due to the induced voltage reversal and carbon corrosion in the anode catalyst layer (ACL) and gas diffusion layer. In this paper, reversal-tolerant anodes (RTAs) with different ACL configurations are proposed, where IrO_x/C is used as a water electrolysis catalyst. Experimental results show that the separate IrO_x/C catalyst layer of MEA samples, layered reversal-tolerant catalyst-coated membrane (layered-RTA), and reversal-tolerant gas diffusion electrode (GDE-RTA) significantly enhance the reversal tolerance and cell performance compared to conventional anode and common RTA consisting of a homogeneous catalyst layer mixed with IrO_x/C and Pt/C (hybrid-RTA). Of these, GDE-RTA possessed a reversal tolerance time of 86 min, a power density of 1.42 W cm⁻², and a minimum degradation rate of 2.4 mV min⁻¹, suggesting it to be the best RTA structure. Cyclic voltammetry and electrochemical impedance spectrum were used to detect the properties of each sample. Additionally, the degradation mechanisms of the three RTAs are thoroughly investigated and discussed by means of microstructural characterization through scanning electron microscopy and transmission electron microscopy. This work provides novel ideas for the fabrication of a robust RTA by tuning the ACL configuration, which is practical for the commercialization of fuel cells. Full article

(This article belongs to the Special Issue Design, Testing and Fault Diagnosis for Fuel Cells)

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13 pages, 4703 KiB

Open AccessArticle

Investigation on Energy Flow Characteristics of Fuel Cell System Based on Real Vehicle Tests

by Zhijie Duan, Chen Li, Lili Feng, Shuguang Yu, Zengyou Jiang, Xiaoming Xu, Jichao Hong and Dongfang Chen

Energies 2021, 14(23), 8172; https://0-doi-org.brum.beds.ac.uk/10.3390/en14238172 - 06 Dec 2021

Cited by 1 | Viewed by 1467

Abstract

For fuel cell hybrid vehicles, the energy distribution mechanism of the fuel cell and power battery should reasonably allocate the power output of the fuel cell and power battery, optimize the efficiency of both and control the power battery SOC to fluctuate within [...] Read more.

For fuel cell hybrid vehicles, the energy distribution mechanism of the fuel cell and power battery should reasonably allocate the power output of the fuel cell and power battery, optimize the efficiency of both and control the power battery SOC to fluctuate within a reasonable range. To test the energy flow and operation characteristics of the powertrain of two hybrid car models on the market, two test vehicles (called vehicle A and vehicle B in this paper) are tested on an AIP 4WD chassis dynamometer under constant power and the China Light-Duty Vehicle Test Cycle-Passenger cycle condition, respectively. The test results show that vehicle A has a smaller power battery SOC variation interval and a lower variable rate than vehicle B. The cumulative power battery output energy of vehicle B is more significant than that of vehicle A. More importantly, the current rare public test reports of fuel cell vehicles make this study very valuable. This paper has important reference significance for the energy flow characteristics and energy management strategy of existing fuel cell hybrid vehicles. Full article

(This article belongs to the Special Issue Design, Testing and Fault Diagnosis for Fuel Cells)

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19 pages, 4699 KiB

Open AccessArticle

Research on Economic and Operating Characteristics of Hydrogen Fuel Cell Cars Based on Real Vehicle Tests

by Zhijie Duan, Luo Zhang, Lili Feng, Shuguang Yu, Zengyou Jiang, Xiaoming Xu and Jichao Hong

Energies 2021, 14(23), 7856; https://0-doi-org.brum.beds.ac.uk/10.3390/en14237856 - 23 Nov 2021

Cited by 11 | Viewed by 3681

Abstract

With the increase of the requirement for the economy of vehicles and the strengthening of the concept of environmental protection, the development of future vehicles will develop in the direction of high efficiency and cleanliness, and the current power system of vehicles based [...] Read more.

With the increase of the requirement for the economy of vehicles and the strengthening of the concept of environmental protection, the development of future vehicles will develop in the direction of high efficiency and cleanliness, and the current power system of vehicles based on traditional fossil fuels will gradually transition to hybrid power. As an essential technological direction for new energy vehicles, the development of fuel cell passenger vehicles is of great significance in reducing transportation carbon emissions, stabilizing energy supply, and maintaining the sustainable development of the automotive industry. To study the fuel economy of a passenger car with the proton exchange membrane fuel cell (PEMFC) during the operating phase, two typical PEMFC passenger cars, test vehicles A and B, were compared and analyzed. The hydrogen consumption and hydrogen emission under two operating conditions, namely the different steady-state power and the Chinese Vehicle Driving Conditions-Passenger Car cycle, were tested. The test results show the actual hydrogen consumption rates of vehicle A and vehicle B are 9.77 g/kM and 8.28 g/kM, respectively. The average hydrogen emission rates for vehicle A and vehicle B are 1.56 g/(kW·h) and 5.40 g/(kW·h), respectively. By comparing the hydrogen purge valve opening time ratio, the differences between test vehicles A and B in control strategy, hydrogen consumption, and emission rate are analyzed. This study will provide reference data for China to study the economics of the operational phase of PEMFC vehicles. Full article

(This article belongs to the Special Issue Design, Testing and Fault Diagnosis for Fuel Cells)

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