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To achieve the 8000-h proton exchange membrane fuel cell stack (PEM FCS) life target set by the U.S DoE and promote fuel cell hybrid electric vehicles (FCHEVs) massive introduction in the automotive market, using multi-fuel cell stack (MFCS) systems instead of single-fuel cell stack systems seems to be an interesting solution that deserves to be explored. MFCS systems' concept combines several small FCSs modules instead of using a single high-powered FCS module. The modularity in such systems can be exploited through energy management to improve their durability and extend their good energy-efficiency power range. However, FCSs' multiplicity makes it challenging to implement effective energy management strategies (EMSs). This paper proposes a remaining useful life (RUL) prognostic-based EMS to extend MFCS systems' lifetime while keeping their hydrogen consumption reasonable. For this purpose, a prognostic algorithm is developed to predict PEM FCSs' RUL in real-world automotive application scenarios. Then a rule-based EMS allocates the demand between stacks using prognostic results. The proposed strategy's performance is evaluated on a hybrid MFCS/battery system using Matlab/Simulink's environment. Simulation results show that implementing the proposed strategy instead of conventional EMSs can extend MFCS systems' lifetime by at least a factor of 2.35 while keeping their hydrogen consumption reasonable. © 2001 Elsevier Science. All rights reserved. • A post-prognostic decision-making strategy is proposed for MFCS systems. • RUL predictions are performed in real-world automotive scenarios. • The MFCS system's lifetime is significantly extended with the proposed EMS. • RUL is a suitable parameter for adaptive energy management decision-making. [ABSTRACT FROM AUTHOR]

Nowadays, efforts for substitution of fossil fuel vehicles have fixed the attention of both individual and governmental levels on seeking new sustainable energy resources. In this regard, several power sources, such as fuel cells (FCs), batteries, and gensets, have come under attention to be used in vehicles with low or zero emissions. Generally, every energy source comes with a set of challenges, which are mainly associated with the efficiency, availability, durability, and cost. This paper is going to touch on the principle of employing a modular energy system (MES), and how this principle is helping the above-mentioned sources to deal with their limitations. MESs refer to independent power sources, which can work together. The aim of a MES is to distribute the power among the components and/or to split the energy storage into several standardized modules, which leads to several economical and technical benefits. Various examples of MESs in real applications are explored, and their advantages are discussed in this manuscript. Moreover, a special attention has been paid to the prospects of employing modular FC systems coupled with a battery pack since such a system has the advantages of a MES while it has no serious environmental impacts. [ABSTRACT FROM AUTHOR]

Achieving independence from fossil fuels and reducing emissions by increasing energy efficiency and utilizing green vehicles, such as hybrid electric vehicles and alternative green fuels, are among the main goals of energy policies globally. Although electric cars were introduced many years ago, agricultural electric vehicles have recently gained attention. Beyond emissions reductions, the benefits of agricultural electric vehicles include precise control, continuous variable speeds, and overload capability functionality. Moreover, such technology paves the way for the emergence of autonomous connected vehicles, which enhance work quality and increase operator comfort. Along with the electrification of agricultural vehicles, on-site production of renewable energy to supply their required power enhances the benefits in terms of increased efficiency and energy independence as a future-oriented approach. This paper outlines the trends in development and future perspectives of autonomous farm vehicles premised on green energies, with on-site energy production as a byproduct. [ABSTRACT FROM AUTHOR]

Current issues concerning global warming and fossil fuel energy shortages impose to find alternatives in order to meet the growing planet's energy demand. The automotive sector is particularly concerned with these issues. The fuel cell seems to be a very promising technology. This article addresses a technological aspect of the integration of fuel cell on a vehicle. The chosen configuration is a multi-pack system favoring the use of several reduced power fuel cells. The energy management method is described along with the sizing and some simulation results. [ABSTRACT FROM AUTHOR]

Air transportation contributes significantly to harmful and greenhouse gas emissions. To combat these issues, there has been a recent emergence of aircraft electrification as a potential solution to mitigate environmental concerns and address fuel shortages. However, current technologies related to batteries, electric machinery, and power systems are still in the developmental phase to meet the requirements for power and energy density, weight, safety, and reliability. In the interim, there is a focus on the more electric and hybrid electric propulsion systems for aircraft. Hydrogen, with its high specific energy and carbon-free characteristics, stands out as a promising alternative fuel for aviation. This paper is centred on the application of hydrogen in aircraft propulsion, mainly fuel cell hybrid electric (FCHE) propulsion systems. Furthermore, application of hydrogen as a fuel for the aircraft propulsion systems is considered. A comprehensive overview of the hydrogen propulsion systems in aviation is presented with an emphasis on the technical aspects crucial for creating a more sustainable and efficient air transportation sector. Additionally, the paper acknowledges the technical and regulatory challenges that must be addressed to attain these goals. [Display omitted] • A comprehensive review of hydrogen propulsion systems for aviation is presented. • Key focus on PEMFC and SOFC systems for aircraft propulsion and auxiliary power. • Advances and challenges in hydrogen storage, water management, and fuel cell degradation. • State-of-the-art energy management strategies for fuel cell systems are discussed. • Future perspectives on hydrogen-powered aviation and necessary technological advancements. [ABSTRACT FROM AUTHOR]

• Energy and power densities quantitation of Li-ion cells (NMC NCA) from −20 to 55 °C. • Investigation and validation of an efficient model only based on datasheet at 25 °C. • Extension of this electro-thermal model to wider temperature and power ranges. • Proposition of a non-isothermal Ragone plot to select the most suitable Li-ion cells. Ragone plot is a conventional tool to compare different energy storage systems in terms of energy and power densities. The selection of the most suitable Li-ion technology for a given application is usually based on the specific energy and power extracted from datasheets at ambient temperatures (25 °C). However, these values are highly temperature-dependent. This study investigates experimentally and via numerical simulations a quantification of the energy and power densities for two different Li-ion chemistry cells in a wide operating temperature range. The experimental results reveal that these values determined from constant current discharge are approximately 15% higher than those determined for a constant power discharge. Therefore, a simple and efficient coupled electrical–thermal model based on an equivalent circuit model (ECM) is proposed, which is able to estimate the voltage, temperature, and available discharged energy of 18,650 Li-ion cells with a good accuracy. Moreover, all parameters in the model can be directly identified with manufacturer's datasheets at 25 °C. Then, the proposed Ragone plot model can be extended to wider temperature and power ranges. The relative error of the simulated energy density is below 2% for both technologies for all operating conditions from – 20 °C to 55 °C. Thus, a non-isothermal Ragone plot is established by considering the thermal effect for the first time. The proposed method could be employed as a conception aid tool for the selection of Li-ion cells in a system design process. [ABSTRACT FROM AUTHOR]

Proton Exchange Membrane Water Electrolyzers demonstrate significant potential for hydrogen production from renewable energy sources. Addressing the inherent intermittency of these sources, a modular design for the electrolyzers emerges as an essential avenue of research. This study delves into potential solutions and strategies for harnessing renewable energy efficiently to fuel these electrolyzers and presents a comparative analysis between single-stack and modular designs based on a hypothetical scenario. Using experimental data, the research projects the hydrogen output derived from solar energy in Trois-Rivières. Machine learning techniques are employed to forecast available energy from photovoltaic panel datasets. A strategic power allocation mechanism is introduced to regulate input current across each electrolyzer, aiming to optimize system performance. Experimental evaluations on a purpose-built test bench validate the conversion efficiency of the electrolyzer. Notably, the results suggest that embracing a modular design can amplify hydrogen production by over 33% annually while concurrently minimizing system degradation. • A modular PEMWE design to tackle renewable energy intermittency is proposed. • Machine learning is used to forecast hydrogen production from solar energy. • A ∼33% increase in hydrogen production and 7.6% degradation reduction is observed. • Efficiency enhancement is accomplished through the suggested modular configuration. [ABSTRACT FROM AUTHOR]

Decarbonized hydrogen production using renewable energy sources and water electrolysis is perceived as a promising solution for a sustainable future. The efficiency of PEMWEs relies on several multiphysical aspects and even a slight increase in their efficiency may change the future of sustainable energy routes. Hence, this paper reviews the most compelling research on increasing PEMWE efficiency, which is one of the main pillars for the advancement of this technology. Various publications, including chemical engineering, materials, mass transfer, energy transfer, electrical control, power generation, and hybrid systems, are considered. From the electrolyzer power sources (renewable energy, hybrid, power to gas), inputs (power regulation, water temperature, pressure, ambient temperature), and stack, to components design, control strategy, and new hybrid designs have come under scrutiny in this manuscript. Finally, five essential recommendations are given as the pathways for future studies on PEMWE efficiency. [ABSTRACT FROM AUTHOR]

This research conducts a comprehensive evaluation of various Proton Exchange Membrane Water Electrolyzer (PEMWE) models through a test bench, optimizing parameters and comparing obtained models against real-world data. Key operational factors such as reversible potential, activation overpotential, ohmic overpotential, and concentration overpotential are examined through experimental data. This study addresses critical gaps in current PEMWE research by reviewing modelling approaches, introducing a novel classification of models, and proposing an integrated approach that combines experimental validation with comprehensive model analysis. A novel, systematic methodology for model and submodel selection is presented, enabling practitioners to identify models that balance computational efficiency and predictive accuracy tailored to specific energy management and power allocation needs. This approach bridges the gap between complex modelling and industrial applications, enhancing the practical implementation of PEMWE systems in sustainable hydrogen production. Enhances model reliability for operational and manufacturing differences, provides invaluable guidance for improving the design and operation of these systems, and promotes a more robust and efficient hydrogen energy infrastructure. [Display omitted] • Proposes a novel classification method for PEMWE models. • Combines empirical data and analysis for accurate PEMWE model comparisons. • Introduces a new method to compare submodels across configurations. • Enhances model reliability for operational and manufacturing differences. [ABSTRACT FROM AUTHOR]

• A scalable energy management strategy for multi-stack fuel cell systems is developed. • The method serves as a benchmark for energy management in fuel cell systems. • The method is applicable to various heavy-duty vehicle applications. • The strategy considers the health condition of fuel cell stacks during operation. • Designed filters enhance the time efficiency of the methodology. This paper puts forward an offline optimal energy management strategy (EMS) for a multi-stack fuel cell (FC) hybrid electric vehicle (HEV) aimed at reducing both fuel consumption and degradation of FC stacks. This method is anticipated to serve as a benchmark for evaluating the performance of online EMSs in future studies. To achieve this goal, a constrained exploration method (CEM) is proposed for power allocation among different energy/power sources. Exploration methods often suffer from time-consuming processes and the curse of dimensionality, particularly when the number of control and state variables increases. To address these issues, the proposed CEM incorporates various filters for the effective calculation of battery power, battery state of charge (SOC) range, and SOC interpolation. The proposed method also utilizes a health-conscious multi-objective cost function intended for minimizing operational costs, including hydrogen consumption and degradation. CEM is introduced as a novel scalable, health-conscious and time-efficient EMS benchmark for hybrid multi-stack FC systems, efficiently decreasing operational expenses and notably shortening simulation duration. The effectiveness of the proposed method is validated through tests conducted on three heavy-duty vehicles as case studies. The first case involves an aircraft, the NASA X-57 Maxwell, fitted with two 50 kW stacks and a battery pack. The validation of the CEM is established by comparing it to level-set dynamic programming (DP) and sequential quadratic programming (SQP) in terms of accuracy and required calculation time. In the second case study, a tramway containing two 125 kW FC stacks is investigated. The validity of the CEM is approved by level-set DP and SQP algorithms. In the third case study, a truck is considered, equipped with four 75 kW FC stacks and a battery system. Level-set DP fails to do the power distribution in this case owing to the numerous state and control variables, whereas the proposed CEM successfully distributes the power among the power sources. Also, results from a comparison of the CEM and SQP methods demonstrate the superiority of CEM. This case study highlights the potential for scalability of the proposed methodology compared to the conventional DP approach found in the literature. [ABSTRACT FROM AUTHOR]

Electric recreational vehicles represent a new challenge in terms of power supply systems compared to the current light-duty electric vehicles, which achieve high performance and long-range. The recreational vehicles need to heed the limited dimension requirements while assuring the high requested power. This paper proposes an integration of Lithium-Ion Capacitor (LIC) with Fuel Cell (FC) without any power electronic device for a three-wheel electric motorcycle. Unlike other hybrid power supply systems, the proposed FC-LIC passive configuration is lighter, compact, more efficient, and simpler to implement. Due to the different impedance of the components the system is self-management, in which FC supplies the average power component and LIC operates as a low-pass filter. In this respect, a simulator is built based on experimental tests to study the system performance in terms of hydrogen consumption and FC degradation. Subsequently, the system is tested under three standard motorcycle driving cycles at three different FC system lifespan stages. The obtained results demonstrate that a passive topology can supply the requested power along different FC stages of life and reported just an increment of 12% of hydrogen consumption at the oldest condition compared to the new condition. [Display omitted] • Integration of LIC technology with a fuel cell system for a recreational vehicle. • Development of a hybrid FC-LIC vehicle simulator based on experimental data. • The system is tested under standard driving cycles at different FC lifespan stages. • The proposed passive design supplies the requested power under all the conditions. • The passive FC-LIC topology is lighter, simpler to implement and self-management. [ABSTRACT FROM AUTHOR]

[Display omitted] • Improved method specifically designed to determine berth emissions of cargo ships. • First specific review for berth emission estimation methods of cargo ships. • Assessing oceangoing ships shore power potential in St. Lawrence and Great Lakes. • New "exclusion area" technique for berthed mode determination. This study investigates for the first time the emissions that a future shore power policy can eliminate in the St. Lawrence and Great Lakes region, providing precise evaluations with an improved bottom-up methodology. The review of cargo ship emission estimation methods showed that latest studies use a methodology that is not suited for evaluating real emissions at berth, but rather general emissions of the ships while at sea. Therefore, an improved method is proposed to determine the emissions specifically at berth with a modified bottom-up analysis that considers further geographical data, operating modes, berth-specific data, the new exclusion-area technique, and new cargo ship types. Also, the results of the proposed method applied in the St. Lawrence and Great Lakes showed that shore power policies can reduce up to an annual maximum of 227,061 t of carbon dioxide equivalent and 25 million dollars annually in external costs to society and governments. [ABSTRACT FROM AUTHOR]

Active configuration i.e., source coupling via a power converter, is the most common configuration for fuel cell/supercapacitor (FC/SC) vehicles. Passive connection of the FC with the SCs without any converters is an original and less expensive solution to distribute the power among the sources. This passive configuration does not require an energy management strategy. In fact, the power distribution only depends on the FC and SC impedance characteristics. Conventional methods to size the SC follow two criteria: storage capacity and maximum voltage. In this paper, a third criterion is added which is the FC operating current dynamics. This novel sizing methodology reduces the FC degradation and improves the global system efficiency. Experimental results provide validation to the proposed sizing approach. The SCs boost the FC to meet the requirements of the load with a guarantee of system stability reaching higher global performances and less stress to the FC. • Low-cost passive configuration between fuel cell and supercapacitor is employed. • A frequency-based sizing methodology is proposed for the fuel cell system. • Higher global performance and less stress to the fuel cell system are achieved. [ABSTRACT FROM AUTHOR]

This study aims at highlighting the impact of the sizing of a hybrid multi-stack fuel cell – battery system on its behavior. Using a rule based energy management strategy, the influence of the hybridization rating is studied. The system's fuel consumption, operation duration, start/stop cycles, ampere-hour throughput and state of charge deviation are evaluated using an Energetic Macroscopic Representation (EMR) based dynamic model. The simulation results predict and expected superiority in both fuel economy and system degradation for systems with a high hybridization ratings whereas the use of systems with low hybridization ratings results in a reduced battery depth of discharge. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the energy management problem for a Fuel Cell Plug-in Hybrid Electric Vehicle is investigated using a real-time power splitting method that preserves the battery pack life. The reduction of high-power demand during the vehicle stop-and-go operations and the limitation of the batteries'' minimum energy to a prescribed level are the two aspects considered in this study. Using a longitudinal motion model of an experimental small utility truck, a multi-criteria optimization problem, including the hydrogen/electricity cost ratio and the anticipation of the high-power demand, is formulated and solved. The analysis of the effects of the fuel cell and the battery efficiency degradations demonstrated that there exists a minimum cost ratio that prevents the Energy Management System to adequately limit the batteries'' depletion with the contribution of the Fuel Cell power. The overall control system does not require a prior knowledge of the trip information. Therefore, the real-time implementation of this system is realistic. Compared with a rule-based Energy Management System, the proposed optimal and real-time approach provides up to 5% of hydrogen saving whilst maintaining the Battery Pack energy close to the minimum prescribed energy. The high-power demand reduction and the depletion limitation enable the Energy Management System to preserve the batteries'' life. [Copyright &y& Elsevier]

• An online fuel cell characteristics estimator based on data fusion is proposed. • Kalman filter is utilized as an attested online parameter estimation algorithm. • Voltages of four semi-empirical models are fused by covariance intersection method. • Polarization and power curves are extracted online with high precision. Employing semi-empirical models to estimate some characteristics of a fuel cell (FC) stack, such as power and polarization curves, is demanded for efficient design of a power allocation strategy in a FC hybrid electric vehicle. However, the multivariate nature of a FC system has made the design of an accurate model challenging. Since each semi-empirical model has its own pros and cons, this paper puts forward a data fusion approach for online characteristics estimation of a FC stack utilizing four well-known models, namely Mann, Squadrito, Amphlett, and Srinivasan. Despite the other similar techniques, the suggested one utilizes the strengths of each mentioned FC model while avoiding their drawbacks. Kalman filter is employed to identify the parameters of the models online to embrace the uncertainties caused by the alteration of operating conditions and degradation level. Considering the parameters, the output voltage given by each model as well as their covariance are computed. Then, a covariance intersection algorithm is proposed to fuse the estimated output voltages. The fusion of the models' outputs leads to the estimation of fused characteristics curves. To underline the effectiveness of the proposed method, it is applied to four different experimental datasets extracted from three 500-W Horizon FCs. The obtained results demonstrate the superior performance of the suggested estimator in the sense of mean square error. On average, the mean square error of the data fusion method is 39.64 % and 36.59 % lower than other studied methods while estimating the polarization curve and power curve, respectively. [ABSTRACT FROM AUTHOR]