Performance Analysis of Ground-Based Static Test for Hydrogen Fuelcell Propulsion System

Challenges and opportunities in modelling of proton exchange membrane fuel cells (PEMFC)

Prognosis of fuel cell degradation under different applications using wavelet analysis and nonlinear autoregressive exogenous neural network

The design of the power source in the Fuel Cell Hybrid Electric Vehicle (FCHEV) is an attractive area in transport applications. The FCHEV combines a Proton Exchange Membrane Fuel Cell (PEMFC) and an Ultra-Battery (UB). A suitable UB is deployed, in FCHEV, for a backup system using efficient energy management. The UB aims to guarantee a rapid transfer of power during transient responses and a permanent power during the absence of hydrogen. To ensure the required power, EMSs have been proposed. An efficiency band UB Partial Load State (PSoC <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">UB</sub> ) is used to evaluate the proposed design. Therefore, the reliability of our model is tested and evaluated through different results using Matlab / Simulink environment.

Power control techniques for fuel cell hybrid electric vehicles: A comparative study

Reviewing metal supported solid oxide fuel cells for efficient electricity generation with biofuels for mobility

PEM Fuel cells, characterized by low operating temperature, fast response, high energy density and high efficiency, have found their place in automotive applications. However, the durability of on-board fuel cells is facing challenges. Aiming at improving system durability and reliability, prognostics and health management, as a smart manufacturing discipline, have been applied to monitor the system health state and protect the system integrity. This paper proposes to combine prognostics when developing energy management strategies for fuel cell electric vehicles, which is used to assess and predict the fuel cell performance. This paper has also considered the uncertainties of the prognostics results and a prognostics-enabled decision-making process is designed as the post-prognostics process to perform energy management in a fuel cell hybrid electric vehicle.

Proton exchange membrane (PEM) fuel cells have gained increasing interest from academia and industry, due to its remarkable advantages including high efficiency, high energy density, high power density, and fast refueling, also because of the urgent demand for clean and renewable energy. One of the biggest challenges for PEM fuel cell technology is the high cost, attributed to the use of precious platinum group metals (PGM), e.g., Pt, particularly at cathodes where sluggish oxygen reduction reaction takes place. Two primary ways have been paved to address this cost challenge: one named low-loading PGM-based catalysts and another one is non-precious metal-based or PGM-free catalysts. Particularly for the PGM-free catalysts, tremendous efforts have been made to improve the performance and durability—milestones have been achieved in the corresponding PEM fuel cells. Even though the current status is still far from meeting the expectations. More efforts are thus required to further research and develop the desired PGM-free catalysts for cathodes in PEM fuel cells. Herein, this paper discusses the most recent progress of PGM-free catalysts and their applications in the practical membrane electrolyte assembly and PEM fuel cells. The most promising directions for future research and development are pointed out in terms of enhancing the intrinsic activity, reducing the degradation, as well as the study at the level of fuel cell stacks.

10 - Novel fuel cells and materials

Proton-Exchange Membrane (PEM) Fuel Cells have the potential to contribute to the future of emission-free, efficient power systems for a wide range of applications. However, operational lifetime of the fuel cells is limited due to failure of cell components, with the membrane being one of the key ones. In PEFCs, chemical decomposition of the membrane due to the attacks of radicals formed during operation along with formation of pinholes, cracks, and delamination influenced by mechanical stressors leads to increased crossover of reactant gases and reduced power loss. Since the chemical and mechanical stressors are largely influenced by the temperature and humidity, it is difficult to determine what mechanisms dominate the membrane lifetime in operation. To understand underlying mechanisms of failure under chemical, mechanical, and combined chemical-mechanical degradation modes, and assess membrane lifetime in shorter time periods, accelerated stress testing (AST) methods are commonly employed. Swelling (or hydration) of the membrane is a key property in fuel cells since it controls both conductivity and stability of the membrane, which could be related to the cell performance and durability, respectively. Swelling-induced operational stresses in the membrane trigger failure mechanisms in the form of cracks or delamination, the impact of which could be further accelerated in the presence of chemical degradation.In this talk, the mechanical aspects of the durability of the polymer fuel cell membranes will be discussed at multiple length-scales. First, membrane's mechanical response during cell operation will be discussed along with the effects of swelling and mechanical properties. We will elaborate on how membrane deformation could be related to the mechanical failure modes ranging from fatigue behavior to the growth of pinholes and cracks, depending on the operating conditions and stress-states. Strategies that could potentially improve membrane durability by tuning its properties will also be discussed. The results will be demonstrated using experimental data as well as modeling methodologies.We will then show how the swelling and properties of membranes change with degradation by focusing on perfluorosulfonic-acid (PFSA) ionomers, the most widely studied membrane in PEM fuel cells. Changes in structure-property relationship of PFSA membranes due to degradation are highlighted based on the investigations on the morphology, mechanical properties and water uptake of degraded membranes. By studying the correlations between measured properties and structural features one can better understand the mechanical aspects of degradation. We will also elaborate how chemical and mechanical stressors could influence each other and control the overall membrane failure. Lastly, mechanistic approaches will be introduced to identify key membrane properties for mechanical durability, to simulate membrane deformation and failure, and to explore models for lifetime prediction. Acknowledgements The authors would like to thank the Los Alamos Fuel Cell Team for their help preparing the degraded membrane samples and for helpful discussions. This work was funded by the Assistant Secretary for Energy Efficiency and Renewable Energy, Fuel Cell Technologies Office, of the U.S. Department of Energy under contract number DE-AC02-05CH11231.

Fuel cells use electrochemical processes to transform the chemical energy of a fuel into electrical energy, which is a key enabler for the shift to an H2-based economy. Because of their high energy conversion efficiency and low pollution emissions, fuel cells with polymer electrolyte membranes (PEMFCs) are regarded as being in frontline of commercialization for the transportation and automotive industries. However, there are two major hurdles to their future commercialization: cost and durability, which promote basic study and development of their components. In this article, we reviewed the materials, functional components, fabrication technologies and assembling characteristics related to PEMFCs. Platinum's significance as a catalyst in PEMFC applications stems from the fact that it beats all other catalysts in three critical parts: stability, selectivity, and activity. In order to create Pt rich surfaces of NPs, Pt metal is alloyed with d-block metals like Cu, Ni, Fe, and Co. PEMFC development is inextricably tied to the benefits and drawbacks of the Nafion membrane under various operating circumstances. Nafion membrane has some drawbacks, including poor performance at high temperatures (over 90℃), low conductivity under low humidification, and high cost. As a result, a variety of nanoscale additives are frequently added to Nafion nanocomposites to enhance the material's properties under fuel cell working conditions. Fiber composite based bipolar plates can deliver best performance. The assembly of PEMFC based on strap approach is being explored. The applications of PEMFC are also projected.

Energy storage and conversion is a very important link between the steps of energy production and energy consumption. Traditional fossil fuels are a natural and unsustainable energy storage medium with limited reserves and notorious pollution problems, therefore demanding a better choice to store and utilize the green and renewable energies in the future. Energy and environmental problems require a clean and efficient way of using the fuels. Fuel cell functions to efficiently convert oxidant and chemical energy accumulated in the fuel directly into DC electric, with the by-products of heat and water. Fuel cells, which are known as effective electrochemical converters, and electricity generation technology has gained attention due to the need for clean energy, the limitation of fossil fuel resources and the capability of a fuel cell to generate electricity without involving any moving mechanical part. The fuel cell technologies that received high interest for commercialization are polymer electrolyte membrane fuel cells (PEMFCs), solid oxide fuel cells (SOFCs), and direct methanol fuel cells (DMFCs). The optimum efficiency for the fuel cell is not bound by the principle of Carnot cycle compared to other traditional power machines that are generally based on thermal cycles such as gas turbines, steam turbines and internal combustion engines. However, the fuel cell applications have been restrained by the high cost needed to commercialize them. Researchers currently focus on the discovery of different materials and manufacturing methods to enhance fuel cell performance and simplify components of fuel cells. Fuel cell systems’ designs are utilized to reduce the costs of the membrane and improve cell efficiency, durability and reliability, allowing them to compete with the traditional combustion engine. In this review, we primarily analyze recent developments in fuel cells technologies and up-to-date modeling for PEMFCs, SOFCs and DMFCs.

A new cost-minimizing power-allocating strategy for the hybrid electric bus with fuel cell/battery health-aware control

Electrification in the transportation industry is becoming more important to face global warming and replace fossil fuels in the future. Among the available energy sources Li-ion battery and proton exchange membrane fuel cell (PEMFC) are the most promising energy sources. Therefore, employing them in fuel cell hybrid electric vehicles (FCHEVs) to combine their advantages is one of the favorable solutions. However, they still face a major challenge residing in their aging that cause the drop of system performance. On one hand, the degradation is the result of the interaction between several aging mechanisms that react differently with various operating conditions. On the other hand, a hybrid system requires an essential energy management strategy (EMS) for fuel economy and optimal power share. At the end, this EMS has an important impact on the lifetime of sources in term of reducing or favorizing the degradation. Therefore, it is important to consider the degradation in the objectives of the designed EMS. Since the degradation is usually neglected when designing an EMS, this paper tends to review the possible methods for designing a health-conscious EMS. Hence, this paper presents a summary of the main fuel cell (FC) and Li-ion battery aging mechanisms as well as the useful degradation models for state of health estimation. In addition, the existing works that consider the degradation of on-board energy sources in their approaches for increasing their durability are classified and analysed. Remaining challenges are detailed along with a discussion and outlooks about current and future trends of health-conscious EMS. Author

In this paper, the performance of a 2000-ton hybrid AIP system submarine is investigated by analyzing the weight, volume and efficiency of its propulsion system. The engine of the investigated AIP system employs a low temperature polymer electrolyte membrane fuel cell which makes use of the hydrogen and oxygen as the reactants. More specifically, the reactants of fuel cell in this study are considered from the combination of three fuel storage systems, methanol (MeOH), liquid hydrogen (LH_2) and metal hydride (MH_2), and two oxidant storage systems, liquid oxygen (LOX) and compressed oxygen (O_2). Based on the assumed various daily propulsion load consumptions, a propulsion system of a 3500 kW diesel generator, a 300 kW fuel cell, and a 7500 kWh energy capacity Li-ion battery bank is determined. With the system installed in the submarine, the maximum designed endurance can reach a total of 26 days for the fuel cell using the combination of reactant LH_2+LOX, and the minimum designed endurance can be up to 10 days for using the reactant MH_2+O2. For submarine cruising at zero speed, the submerged endurance of the AIP system using reactant LH2  LOX plus battery bank is 22.8 times of that using battery bank alone. This value will increase to 25.0 times for submarine cruising at 7.4 knots. At the cruising speed of 5.5 knots, the maximum submerged range of submarine increases a factor of 24.1 for fuel cell using the reactant of LH_2+LOX as compared with operation on battery bank alone. Therefore, the submerged endurance is substantial enhanced for using the combination of fuel cell and battery. In addition, the indiscretion ratio is zero for the AIP system submarine with a cruising speed below 7.1 knots; this can greatly reduce the submarine vulnerability. Based on the weight and volume analysis of the submarine equipped with a hybrid AIP system, the usage of the reactant LH_2+LOX is well suited for a small- to medium-sized 2000-ton submarine with a fuel cell system. Furthermore, using the reactant MeOH+LOX has the advantage for large-sized LT-PEMFC AIP system submarines.

This paper is the outcome of a small scale fuel cell project. Fuel cell is an electrochemical device that converts energy from chemical reaction to electrical work. Proton Exchange Membrane Fuel Cell (PEMFC) is one of the different types of fuel cell, which is more efficient, having low operational temperature and fast start up capability results in high energy density. In this study, a mathematical model of 1.2 W PEMFC is developed and simulated using MATLAB software. This model describes the PEMFC behaviour under steady-state condition. This mathematical modeling of PEMFC determines the polarization curve, power generated, and the efficiency of the fuel cell. Simulation results were validated by comparing with experimental results obtained from the test of a single PEMFC with a 3 V motor. The performance of experimental PEMFC is little lower compared to simulated PEMFC, however both results were found in good agreement. Experiments on hydrogen flow rate also been conducted to obtain the amount of hydrogen consumed to produce electrical work on PEMFC.