Control Oriented Discretized Cathode Control Volume Method for Improved PEM Fuel Cell Modeling

Author(s):  
Alexander J. Headley ◽  
Dongmei Chen

The humidity levels in PEM fuel cells has a profound effect on the performance. However, in large fuel cell stacks the relative humidity (RH) changes significantly along the length of the stack. This paper presents a control-oriented model with spatial considerations of the distribution of water vapor that can be used to properly predict and control the humidity levels in a PEM fuel cell stack. This model predicts the dynamic response of the stack in real-time by tracking energy and mass flows in four basic CVs. To provide spatial information of the stack conditions, the cathode CV was further subdivided into 6 sub-volumes. The model was validated with experiments conducted on a 28-cell, 2kW fuel cell stack. The validation results show that the multiple CV approach can accurately predict the stack RH and voltage, and is capable of predicting localized voltage losses. This new modeling methodology shows the importance of a distributed understanding of the RH profile, and provides a tool to create control algorithms for PEM fuel cells that consider the health of all the sections of the stack.

Author(s):  
Praveen Narasimhamurthy ◽  
Zakiul Kabir

UTC Fuel Cells (UTCFC) over the last few years has partnered with leading automotive and bus companies and developed Polymer Electrolyte Membrane (PEM) fuel-cell power plants for various transportation applications, for instance, automotive, buses, and auxiliary power units (APUs). These units are deployed in various parts of the globe and have been gaining field experience under both real world and laboratory environments. The longest running UTC PEM fuel cell stack in a public transport bus has accumulated over 1350 operating hours and 400 start-stop cycles. The longest running APU fuel cell stack has accrued over 3000 operating hours with more than 3200 start-stop cycles. UTCFC PEM fuel-cell systems are low noise and demonstrate excellent steady state, cyclic, and transient capabilities. These near ambient pressure, PEMFC systems operate at high electrical efficiencies at both low and rated power conditions.


2015 ◽  
Vol 12 (1) ◽  
Author(s):  
A. Verma ◽  
R. Pitchumani

Polymer electrolyte membrane (PEM) fuel cells are well suited for automotive applications compared to other types of fuel cells owing to their faster transient response and low-temperature operation. Due to rapid change in loads during automotive applications, study of dynamic behavior is of paramount importance. This study focuses on elucidating the transient response of a PEM fuel cell for specified changes in operating parameters, namely, voltage, pressure, and stoichiometry at the cathode and the anode. Transient numerical simulations are carried out for a single-channel PEM fuel cell to illustrate the response of power as the operating parameters are subjected to specified changes. These parameters are also optimized with an objective to match the power requirements of an automotive drive cycle over a certain period of time.


2005 ◽  
Vol 2 (4) ◽  
pp. 226-233 ◽  
Author(s):  
Shaoduan Ou ◽  
Luke E. K. Achenie

Artificial neural network (ANN) approaches for modeling of proton exchange membrane (PEM) fuel cells have been investigated in this study. This type of data-driven approach is capable of inferring functional relationships among process variables (i.e., cell voltage, current density, feed concentration, airflow rate, etc.) in fuel cell systems. In our simulations, ANN models have shown to be accurate for modeling of fuel cell systems. Specifically, different approaches for ANN, including back-propagation feed-forward networks, and radial basis function networks, were considered. The back-propagation approach with the momentum term gave the best results. A study on the effect of Pt loading on the performance of a PEM fuel cell was conducted, and the simulated results show good agreement with the experimental data. Using the ANN model, an optimization model for determining optimal operating points of a PEM fuel cell has been developed. Results show the ability of the optimizer to capture the optimal operating point. The overall goal is to improve fuel cell system performance through numerical simulations and minimize the trial and error associated with laboratory experiments.


2019 ◽  
Vol 30 (4) ◽  
pp. 2077-2097 ◽  
Author(s):  
Zhenxiao Chen ◽  
Derek Ingham ◽  
Mohammed Ismail ◽  
Lin Ma ◽  
Kevin J. Hughes ◽  
...  

Purpose The purpose of this paper is to investigate the effects of hydrogen humidity on the performance of air-breathing proton exchange membrane (PEM) fuel cells. Design/methodology/approach An efficient mathematical model for air-breathing PEM fuel cells has been built in MATLAB. The sensitivity of the fuel cell performance to the heat transfer coefficient is investigated first. The effect of hydrogen humidity is also studied. In addition, under different hydrogen humidities, the most appropriate thickness of the gas diffusion layer (GDL) is investigated. Findings The heat transfer coefficient dictates the performance limiting mode of the air-breathing PEM fuel cell, the modelled air-breathing fuel cell is limited by the dry-out of the membrane at high current densities. The performance of the fuel cell is mainly influenced by the hydrogen humidity. Besides, an optimal cathode GDL and relatively thinner anode GDL are favoured to achieve a good performance of the fuel cell. Practical implications The current study improves the understanding of the effect of the hydrogen humidity in air-breathing fuel cells and this new model can be used to investigate different component properties in real designs. Originality/value The hydrogen relative humidity and the GDL thickness can be controlled to improve the performance of air-breathing fuel cells.


Author(s):  
Scott A. Kenner ◽  
Nicholas M. Josefik ◽  
Scott M. Lux ◽  
James L. Knight ◽  
Melissa K. White ◽  
...  

Background: The U.S. Army Engineer Research and Development Center, Construction Engineering Research Laboratory (ERDC-CERL) continues to manage The Department of Defense (DoD) Residential Proton Exchange Membrane (PEM) Fuel Cell Demonstration Project. This project was funded by the United States Congress for fiscal years 2001 through 2004. A fleet of 91 residential-scale PEM fuel cells, ranging in size from 1 to 5 kW, has been demonstrated at various U.S. DoD facilities around the world. Approach: The performance of the fuel cells has been monitored over a 12-month field demonstration period. A detailed analysis has been performed cataloging the component failures, investigating the mean time of the failures, and the mean time between failures. A discussion of the lifespan and failure modes of selected fuel cell components, based on component type, age, and usage will be provided. This analysis also addresses fuel cell stack life for both primary and back-up power systems. Several fuels were used throughout the demonstration, including natural gas, propane, and hydrogen. A distinction will be made on any variances in performance based on the input fuel stock. Summary: This analysis will provide an overview of the ERDC-CERL PEM demonstration fuel cell applications and the corresponding data from the field demonstrations. Special emphasis will be placed on the components, fuel cell stack life, and input fuel characteristics of the systems demonstrated.


2004 ◽  
Vol 19 (6) ◽  
pp. 1723-1729 ◽  
Author(s):  
Neil Aukland ◽  
Abdellah Boudina ◽  
David S. Eddy ◽  
Joseph V. Mantese ◽  
Margarita P. Thompson ◽  
...  

During the operation of proton exchange membrane (PEM) fuel cells, a high-resistance oxide is often formed on the cathode surface of base metal bipolar plates. Over time, this corrosion mechanism leads to a drop in fuel cell efficiency and potentially to complete failure. To address this problem, we have developed alloys capable of forming oxides that are both conductive and chemically stable under PEM fuel cell operating conditions. Five alloys of titanium with tantalum or niobium were investigated. The oxides were formed on the alloys by cyclic voltammetry in solutions mimicking the cathode- and anode-side environment of a PEM fuel cell. The oxides of all tested alloys had lower surface resistance than the oxide of pure titanium. We also investigated the chemical durability of Ti–Nb and Ti–Ta alloys in more concentrated solutions beyond those typically found in PEM fuel cells. The oxide films formed on Ti–Nb and Ti–Ta alloys remained conductive and chemically stable in these concentrated solutions. The stability of the oxide films was evaluated; Ti alloys having 3% Ta and Nb were identified as potential candidates for bipolar plate materials.


Author(s):  
M. I. Rosli ◽  
M. Pourkashanian ◽  
D. B. Ingham ◽  
L. Ma ◽  
D. Borman ◽  
...  

This paper reviews some of the previous research works on direct visualisation inside PEM fuel cells via a transparent single cell for the water behaviour investigation. Several papers which have employed the method have been selected and summarised and a comparison between the design of the cell, materials, methods and visual results are presented. The important aspects, advantages of the method and a summary on the previous work are discussed. Some initial work on transparent PEM fuel cell design using a single serpentine flow-field pattern is described. The results show that the direct visualisation via transparent PEM fuel cells could be one potential technique for investigating the water behavior inside the channels and a very promising way forward to provide useful data for validation in PEM fuel cell modelling and simulation.


Author(s):  
Denise A. McKahn ◽  
Whitney McMackin

We present the design of a multi-cell, low temperature PEM fuel cell for controlled meteorological balloons. Critical system design parameters that distinguish this application are the lack of reactant humidification and cooling due to the low power production, high required power mass-density and relatively short flight durations. The cell is supplied with a pressure regulated and dead ended anode, and flow controlled cathode at variable air stoichiometry. The cell is not heated and allowed to operate with unregulated temperature. Our prototype cell was capable of achieving power densities of 43 mW/cm2/cell or 5.4 mW/g. The cell polarization performance of large format PEM fuel cell stacks is an order of magnitude greater than for miniature PEM fuel cells. These performance discrepancies are a result of cell design, system architecture, and reactant and thermal management, indicating that there are significant gains to be made in these domains. We then present design modifications intended to enable the miniature PEM fuel cell to achieve power densities of 13 mW/g, indicating that additional performance gains must be made with improvements in operating conditions targeting achievable power densities of standard PEM fuel cells.


2022 ◽  
Vol 334 ◽  
pp. 05002
Author(s):  
Andrea Pietra ◽  
Marco Gianni ◽  
Nicola Zuliani ◽  
Stefano Malabotti ◽  
Rodolfo Taccani

This study is focused on the possible application of hydrogen-fed PEM fuel cells on board ships. For this purpose, a test plant including a 100 kW generator suitable for marine application and a power converter including a supercapacitor-based energy storage system has been designed, built and experimentally characterised. The plant design integrates standard industrial components suitable for marine applications that include the technologies with the highest degree of maturity currently available on the market. Fuel Cell generator and power converter have been specifically designed by manufacturers to fit the specific plant needs. The experimental characterisation of the plant has been focused on the evaluation of the efficiency of the single components and of the overall system. Results shows a PEM fuel cell efficiency of 48% (when all auxiliaries are included) and an overall plant efficiency, including power conditioning, of about 45%. From load variation response tests, the fuel cell response time was maximum 2 seconds without supercapacitors and increased up to 20 seconds with supercapacitors connected, reducing the stress on the fuel cell generator. Experimental results confirm that PEM fuel cells, when supported by a suitably sized energy storage system, represent a viable technical solution for zero-emission power generation on board ships.


Author(s):  
Jason R. Kolodziej

The purpose of this paper is to present a nonlinear control method for accurately maintaining coolant temperature within a proton exchange membrane (PEM) fuel cell stack by controlling coolant flow rate. Due to the current sensitive nature of the membrane and a strict relative humidity requirement it is critical to precisely control the internal temperature of the fuel cell. First, an optimization-based parameter identification is applied to determine unknown coefficients to the nonlinear thermal model of the fuel cell stack. The stack is modelled according to a lumped parameter Continuous-flow Stirred Tank Reactor (CSTR) form. The paper then presents a nonlinear disturbance rejection control technique to accomplish the necessary temperature control. Experimental data from a 17-cell fuel cell stack is used for both the modelling and control portions of this work.


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