Temperature PEM Fuel Cell Stack Research Articles

PV-based hybrid residential microgrid with hydrogen and battery energy storage options: a Northern Italy case study

Residential microgrids based on renewable energy sources (RES) are promising solutions for the ongoing energy transition but, at the same time, must also cope with the intermittency of the energy source and the limited energy storage capacity. To overcome such problems, RES-based microgrids usually rely on backup powering systems, such as a stable connection to the main grid or the presence of emergency electricity generators. In order to significantly increase the autonomy of the microgrid and limit the presence of backup solutions, an additional energy storage system based on hydrogen is proposed here, which complements the more classical option of energy storage in batteries. The microgrid under investigation is composed by a PV system, a lithium-ion battery for short term energy storage, and a hydrogen-based storage system composed of a PEM electrolyzer, a pressurized hydrogen tank and a low temperature PEM fuel cell stack. The system is managed by a control system which balances at each time the energy demand with the energy produced from different sources. Results reflect the role of hydrogen as efficient long-term storage option, while the battery fulfills short-terms storage needs. With properly sized components, the microgrid turns out to be fully autonomous during one year and can therefore work also in off-grid mode. The impact of an improved energy management approach is also highlighted, which may lead to increased hydrogen production and higher level of autonomy of the microgrid.

Optimal sizing of a fuel processor for auxiliary power applications of a fuel cell-powered passenger car

The present study considers the optimal sizing of a three-way hybrid powertrain consisting of a compact reformer, a compact battery and a low temperature PEM fuel cell stack serving as the main power unit. A simulation model consisting of the relevant characteristic parameters of the three power sources has been developed and has been used to study the fuel utilization features of the hybrid powertrain while going through the NEDC driving cycle with a given auxiliary power requirement. The optimality is based on minimizing fuel cost while having an assured range of 500 km under practical driving conditions and a further 100 km under reduced auxiliary power usage. It is shown that for performance characteristics of Toyota Mirai and for average auxiliary power consumption of 5 kW, a smaller NiMH battery size of 1.3 kWh together with a fuel processor of 5.6 kW constant output would be optimal with a further requirement of 25% more hydrogen and 33 kg of ethanol to be carried on-board. Substantial reductions in vehicle mass and fuel load can be achieved for more modest performance characteristics and auxiliary power consumption.

Experimental and modelling studies of low temperature PEMFC performance

The performance of a PEMFC (Polymer Electrolyte Membrane Fuel Cell) is greatly influenced by the various operating variables like temperature, pressure, stoichiometry of reactants and humidity. The presented work deals with the experimental study of 30 cells low temperature PEM fuel cell stack employing Nafion®-212 membranes. Experimental results are discussed with polarization curves and compared with the steady state model results, developed in MATLAB. The model predicts increase PEMFC performance with increase in operating temperature, pressure and reactant humidity. The comparison shows good agreement between experimental and modeling results with deviations in the range of 7–15% only.

An EIS alternative for impedance measurement of a high temperature PEM fuel cell stack based on current pulse injection

In this paper a method for estimating the fuel cell impedance is presented, namely the current pulse injection (CPI) method, which is well suited for online implementation. This method estimates the fuel cell impedance and unlike electrochemical impedance spectroscopy (EIS), it is simple to implement at a low cost. This makes it appealing as a characterization method for on-line diagnostic algorithms. In this work a parameter estimation method for estimation of equivalent electrical circuit (EEC) parameters, which is suited for on-line use is proposed. Tests on a 10 cell high temperature PEM fuel cell show that the method yields consistent results in estimating EEC parameters for different current pulse at different current loads, with a low variance. A comparison with EIS shows that despite its simplicity the response of CPI can reproduce well the impedance response of the high and intermediate frequencies.

Dynamic modeling and experimental investigation of a high temperature PEM fuel cell stack

High temperature polymer fuel cells operating at 100 to 200◦C require simple fuel processing and produce high quality heat that can integrate well with domestic heating systems. Because the transportation of hydrogen is challenging, an alternative option is to reform natural gas on site. This article presents the development of a dynamic model and the comparison with experimental data from a high temperature proton exchange membrane fuel cell stack operating on hydrogen with carbon monoxide concentrations up to 0.8%, and temperatures from 155 to 175◦C. The dynamic response of the fuel cell is investigated with simulated reformate gas. The dynamic response of the fuel cell stack was compared with a step change in current from 0.09 to 0.18 and back to 0.09 A/cm2. This article shows that the dynamic model calculates the voltage at steady state well. The dynamic response for a change in current shows that the model compares well with some of the cells in the stack while other cells may have typically lower voltages levels during dynamic operation.

Evaluation of a 2.5 kWel automotive low temperature PEM fuel cell stack with extended operating temperature range up to 120 °C

Nowadays, the operating temperature of polymer electrolyte membrane fuel cell stacks is typically limited to 80 °C due to water management issues of membrane materials. In the present work, short-term operation at elevated temperatures up to 120 °C and long-term steady-state operation under automotive relevant conditions at 80 °C are examined using a 30-cell stack developed at DLR. The high temperature behavior is investigated by using temperature cycles between 90 and 120 °C without adjustment of the gases dew points, to simulate a short-period temperature increase, possibly caused by an extended power demand and/or limited heat removal. This galvanostatic test demonstrates a fully reversible performance decrease of 21 ± 1% during each thermal cycle. The irreversible degradation rate is about a factor of 6 higher compared to the one determined by the long-term test. The 1200-h test at 80 °C demonstrates linear stack voltage decay with acceptable degradation rate, apart from a malfunction of the air compressor, which results in increased catalyst degradation effects on individual cells. This interpretation is based on an end-of-life characterization, aimed to investigate catalyst, electrode and membrane degradation, by determining hydrogen crossover rates, high frequency resistances, electrochemically active surface areas and catalyst particle sizes.

Long term testing of start–stop cycles on high temperature PEM fuel cell stack

A PEM fuel cell with an operating temperature above 100 °C is desired for increasing the kinetics of reactions, reduced sensitivity to impurities of the fuel, as well as for the reduction of the requirements on thermal and water management systems. High Temperature Polymer Electrolyte Membrane Fuel Cells (HT-PEMFC) can effectively be combined with CHP systems to offer a simple system design and higher overall system efficiencies. For HT-PEMFC systems, the development of elaborated start/stop strategies is essential in mitigation of fuel cell degradation during these events. A 5 cell co-flow stack is assembled with BASF P1100W membrane electrode assembly (MEA) with an active area of 163.5 cm2. Continuous operation and more than 1500 start stop cycles have been performed in order to study the degradation effects of both continuous operation and of repeated start stops using a protective start–stop algorithm, which is designed to avoid the formation of aggressive cell potentials. The repeated use of this procedure led to a degradation of 26 μV/cycle at a current density of 0.25 A cm−2 and 11 μV/cycle at a current density of 0.03 A cm−2. At open circuit voltage (OCV), a higher degradation rate of 133 μV/cycle was observed.

Dynamic Analysis and Diagnostics of a High Temperature PEM Fuel Cell Stack

In this work, impedance measurement was performed on a high temperature PEM fuel cell stack module consisting of 65 planar single cells. Pure hydrogen and ambient air were supplied into the stack. The impedance data of the stack were collected under varying loads at 160ºC. However, temperature variations and gradient existed over the whole stack during the measurement. The impedance measurement was then repeated under the same operating conditions to collect the second set of data. An unexpected increase of cell impedance was observed. An EC diagram was derived to simulate the impedance data of the stack module. The electronic auxiliaries and temperature profiles of the stack module were analyzed to study their effects on stack impedance.

In Situ Performance Analysis of a High Temperature PEM Fuel Cell Stack at Loads

A high temperature PEM fuel cell stack, consisting of 65 planar single cells, was operated in a commercial power module with pure hydrogen and ambient air. AC impedance tests were conducted on the stack module after it reached a steady operating status. The equivalent circuit diagram with three time constants was derived to simulate the measured impedance data. The impedance measurement and simulation were performed to the stack module at different operation settings of stack temperature and load current in order to validate the derived equivalent circuit diagram. In this way, the kinetic and mass transfer processes occurring inside the stack were mechanistically discriminated and identified.

Dynamic Analysis and Diagnostics of a High Temperature PEM Fuel Cell Stack

not Available.

Design and experimental characterization of a 350 W High Temperature PEM fuel cell stack

High Temperature Proton Exchange Membrane (HT PEM) fuel cell based on polybenzimidazole (PBI) polymer and phosphoric acid, can be operated at temperature between 120 °C and 180 °C. Reactants humidification is not required and CO content up to 2% in the fuel can be tolerated, affecting only marginally performance. This is what makes HT PEM very attractive, as low quality reformed hydrogen can be used and water management problems are avoided. Till nowadays, from experimental point of view, only few studies relate to the development and characterization of high temperature stacks. The aim of this work is to present the main design features and the performance curves of a 25 cells HT PEM stack based on PBI and phosphoric acid membranes. Performance curves refer to the stack operating with two type of fuels: pure hydrogen and a gas mixture simulating a typical steam reformer output. The stack voltage distribution analysis and the stack temperature distribution analysis suggest that cathode air could be used as coolant leading to a better thermal management. This could simplify stack design and system BOP, thus increasing system performance

Scale-up of a high temperature polymer electrolyte membrane fuel cell based on polybenzimidazole

A high temperature PEM fuel cell stack with a total active area 150 cm 2 has been studied. The PEM technology is based on a polybenzimidazole (PBI) membrane. Cast from a PBI polymer synthesised in our lab, the performance of a three-cell stack was analysed in static and dynamic modes. In static mode, operating at high constant oxygen flow rate ( Q O 2 > 1105 ml O 2 / min ) produces a small decrease on the stack performance. High constant oxygen stoichiometry ( λ O 2 > 3 ) does not produce a decrease on the performance of the stack. There are not differences between operating at constant flow rate of oxygen and constant stoichiometry of oxygen in the stack performance. The effect of operating at high temperature with a pressurization system and operating at higher temperatures are beneficial since the performance of the fuel cell is enhanced. A large shut-down stage produces important performance losses due to the loss of catalyst activity and the loss of membrane conductivity. After 150 h of operation at 0.2 A cm −2, it is observed a very high voltage drop. The phosphoric acid leached from the stack was also evaluated and did not exceed 2% (w/w). This fact suggests that the main degradation mechanism of a fuel cell stack based on polybenzimidazole is not the electrolyte loss. In dynamic test mode, it was observed a rapid response of power and current output even at the lower step-time (10 s). In the static mode at 125 °C and 1 atm, the stack reached a power density peak of 0.29 W cm −2 (43.5 W) at 1 V.

Characterisation and Modelling of a High Temperature PEM Fuel Cell Stack using Electrochemical Impedance Spectroscopy

Fuel CellsVolume 9, Issue 4 p. 482-482 ErratumFree Access Characterisation and Modelling of a High Temperature PEM Fuel Cell Stack using Electrochemical Impedance Spectroscopy† This article corrects the following: Characterisation and Modelling of a High Temperature PEM Fuel Cell Stack using Electrochemical Impedance Spectroscopy S. J. Andreasen, J. L. Jespersen, E. Schaltz, S. K. Kær, Volume 9Issue 4Fuel Cells pages: 463-473 First Published online: June 5, 2009 S. J. Andreasen, S. J. Andreasen sja@iet.aau.dk Department of Energy Technology, Aalborg University, Pontoppidanstræde 101, DK-9220 Aalborg East, DenmarkSearch for more papers by this authorJ. L. Jespersen, J. L. Jespersen Danish Technological Institute, Kongsvang Allé 29, DK-8000 Arhus C, DenmarkSearch for more papers by this authorE. Schaltz, E. Schaltz Department of Energy Technology, Aalborg University, Pontoppidanstræde 101, DK-9220 Aalborg East, DenmarkSearch for more papers by this authorS. K. Kær, S. K. Kær Department of Energy Technology, Aalborg University, Pontoppidanstræde 101, DK-9220 Aalborg East, DenmarkSearch for more papers by this author S. J. Andreasen, S. J. Andreasen sja@iet.aau.dk Department of Energy Technology, Aalborg University, Pontoppidanstræde 101, DK-9220 Aalborg East, DenmarkSearch for more papers by this authorJ. L. Jespersen, J. L. Jespersen Danish Technological Institute, Kongsvang Allé 29, DK-8000 Arhus C, DenmarkSearch for more papers by this authorE. Schaltz, E. Schaltz Department of Energy Technology, Aalborg University, Pontoppidanstræde 101, DK-9220 Aalborg East, DenmarkSearch for more papers by this authorS. K. Kær, S. K. Kær Department of Energy Technology, Aalborg University, Pontoppidanstræde 101, DK-9220 Aalborg East, DenmarkSearch for more papers by this author First published: 07 August 2009 https://doi.org/10.1002/fuce.200990011 † Paper presented at the MEA'08 Conference, La Grande Motte, 21st–24th September 2008. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume9, Issue4Special Issue: Progress in MEA Components for Medium and High Temperature Polymer Electrolyte Fuel Cells (La Grande Motte, September 2008)August, 2009Pages 482-482 RelatedInformation