Exchange Membrane Fuel Cell System Research Articles

Dynamic Fractional-Order Model of Proton Exchange Membrane Fuel Cell System for Sustainability Improvement

The proton exchange membrane fuel cell (PEMFC) stands at the forefront of advancing energy sustainability. Effective monitoring, control, diagnosis, and prognosis are crucial for optimizing the PEMFC system’s sustainability, necessitating a dynamic model that can capture the transient response of the PEMFC. This paper uses a dynamic fractional-order model to describe the behaviors of a stationary micro combined heat and power (mCHP) PEMFC stack. Based on the fractional-order equivalent circuit model, the applied model accurately represents the electrochemical impedance spectroscopy (EIS) and the dynamic voltage response under transient conditions. The applied model is validated through experiments on an mCHP PEMFC stack under various fault conditions. The EIS data is analyzed under different current densities and various fault conditions, including the stoichiometry of the anode and cathode, the stack temperature, and the relative humidity. The dynamic voltage response of the applied model shows good correspondence with experimental results in both phase and amplitude, thereby affirming the method’s precision and solidifying its role as a reliable tool for enhancing the sustainability and operational efficiency of PEMFC systems.

Environmental and economic assessment of hydrogen-powered ferries for inland transportation

This paper investigates the environmental and economic impacts of hydrogen-powered ferries in inland passenger and car transportation using Life Cycle Assessment (LCA) and Life Cycle Cost Analysis (LCCA). Three types of electrolysers and two types of fuel cells, focusing on their manufacturing locations, are compared with two Marine Diesel Oils (MDOs) with various sulphur percentages. In addition, this study utilises the Analytical Hierarchy Process (AHP) to weigh and rank the environmental impacts of all power options based on expert opinions. As a result of the combination of LCA and AHP analysis, the most environmentally friendly power option is found to be the Solid Oxide Electrolyser-Solid Oxide Fuel Cell system for the case study, while the worst option is the Proton Exchange Membrane Electrolyser- Proton Exchange Membrane Fuel Cell system. Moreover, MDOs are the most cost-effective power options in all carbon-tax scenarios.

Effect of air depletion in the preferential oxidation reactor and fuel depletion in a proton exchange membrane fuel cell system fueled by natural gas

This study estimates the steady-state performance of a proton exchange membrane fuel cell (PEMFC) under conditions of air depletion in the preferential oxidation reactor (PrOx) and fuel depletion at the anode, which has not been previously studied. Considering the detailed chemical reactions of the reforming process, the composition of the reformed gas at the anode inlet is determined using the temperature and pressure data measured at various state points in the PEMFC system. To calculate the voltage loss at the anode due to the air depletion in PrOx or reformate gas depletion before the anode, the electrochemical reaction of the reformed gas in the anode catalyst layer is studied. The calculations show that when the fuel entering the anode or air entering the PrOx decreases, the amount of CO at the anode increases depending on the reduction, resulting in activation loss at the anode, and thereby leading to power loss. This analysis of the power loss in a PEMFC due to a lack of air or fuel can serve as an auxiliary diagnostic tool to identify faulty parts in the Balance of Plant (BOP).

Design, modeling, and optimization of a novel 6 kWe hybrid solid oxide fuel cell high temperature-proton exchange membrane fuel cell system

This work investigates a novel approach in terms of design, configuration, heat integration and optimization of a 6 kWe total energy system fueled with natural gas. Specifically, a Solid Oxide Fuel Cell (SOFC) is used for both electricity generation and fuel reforming, since its exhaust stream fuels a polybenzimidazole (PBI)-based, High Temperature-Proton Exchange Membrane Fuel Cell (HT-PEMFC). The study investigates the possible advantages of such a system in both technical and economic terms. After modeling each component/subsystem, the total system model is optimized with the objective function aiming to maximize the net electrical efficiency of the total hybrid system. The system is optimized with a genetic algorithm-based optimization strategy, reaching a net electrical efficiency of 43.6 %. In comparison to standalone fuel cell systems with the same net electrical power output, the proposed hybrid system outperforms both an HT-PEMFC system and an SOFC system, which perform at net electrical efficiencies of 23.2 % and 40.7 %, respectively. Also, the lifecycle cost for the proposed system is $64,097, which is lower than both standalone HT-PEMFC and SOFC systems. Therefore, with the current high rising costs for natural gas, such highly efficient systems are likely to become important elements of the future energy infrastructure.

Design of cascaded observer of internal oxygen mass for Proton Exchange Membrane Fuel Cell system

The Proton Exchange Membrane Fuel Cell (PEMFC) system’s performance and durability are greatly influenced by the oxygen excess rate (OER). However, the accurate measurement of OER can be challenging due to the comprehensive dynamic mechanism of air supply and consumption. To address this issue, a cascaded sliding mode-extended state observer (SM-ESO) was proposed. The pre-stage observer entails reconstructing the full states via a reduced-order sliding mode observer, utilizing compressor speed and supply manifold pressure. Moreover, the sliding mode gains are online updated to accommodate varying operating conditions. The post-stage extended state observer is presented to extract mass flow rate features of oxygen and to obtain OER. Meanwhile, the two-stage cascade provides accurate observation with low cost. The real-time implementation among the proposed method, sliding mode observer, and extended Kalman filter observer demonstrated that SM-ESO gave a more accurate and robust estimate of OER.

Plasma Technology Applications in Proton Exchange Membrane Fuel Cell Systems

AbstractFuel cells have become a prominent research focus in the realm of clean energy, owing to their attributes of environmental sustainability, high efficiency, and renewable potential. The catalytic activity of electrode materials and the characteristics of proton exchange membranes are considered pivotal determinants of fuel cell performance. Plasma is abundant in high‐energy electrons and active species, proven to be a rapid, facile, and green approach for the preparation and treatment of catalytic materials and polymers. This review presents recent applications of plasma technology in proton exchange membrane fuel cells across four key dimensions: cathodes, anodes, proton exchange membranes, and process enhancement, including the preparation and treatment of noble metal catalysts, non‐noble metal catalysts, non‐metal catalysts, and polymer membranes. Furthermore, critical issues of plasma technology applied in PEMFCs were also discussed.

Comprehensive performance assessment and multi-objective optimization of high-power proton exchange membrane fuel cell system under variable load

Due to the advantages of zero emission, high efficiency and low noise, Proton Exchange Membrane Fuel Cell (PEMFC) has grown to be the spotlight in the field of new energy in recent years. In this work, a high-power PEMFC system model is designed, which consists of the fuel feed Subsystem, the air feed subsystem, the thermal management subsystem and the stack. Among them, the material diffusion in the catalyst layer of the stack is intensively studied and derived. For the comprehensive system performance assessment, the thermodynamic, economic and environmental evaluation models have been developed. The mapping relationships between the operating parameters, the structural parameters and the system comprehensive performance under variable load conditions are obtained. The results of the study prove that increasing the operating temperature and decreasing the membrane thickness under high load current conditions are conducive to increase the system net power output, but at the same time increase the levelized cost of energy and the carbon mass specific emission. In addition, a multi-objective optimization strategy based on the NSGA-Ⅱ is designed to obtain the optimal performance of the system under different operating conditions. The optimized net power, the levelized cost of energy and the carbon mass ratio emission of the system for the final optimal operating point are increased by 40.5 %, 10.3 % and 33.3 % respectively. The aforementioned evidence substantiates the effectiveness of the proposed multi-objective optimization strategy in enhancing the overall performance of the PEMFC system.

Integration of a proton exchange membrane fuel cell system for voltage and frequency stabilization in a micro hydro system

This work discusses the frequency and voltage stabilization in a stand-alone self-excited induction generator system (SEIGs) using a fuel cell (FC)-based generation unit. The proposed SEIG acts as the power generator in a microhydro system. Variations in load create fluctuations in voltage and frequency, which have to be stabilized. In this work, authors have proposed integrating a FC-based generation unit with the existing SEIGs to improve its voltage and frequency profiles. For this work, a proton exchange membrane fuel cell (PEMFC) has been considered. Modeling of a 36 kW PEMFC is taken for the proposed work, which has to be integrated with the 22 kW self-excited induction generator. The design of the system and converter parameters have also been included in the work. Authors have proposed an orthogonal current component-based controlstructure that provides independent control of active and reactive power in the system. Considering the FC system working conditions, this article aims to assure optimum power transfer capability between the self-excited induction generator, fuel cell system, and the time-varying loads. The system is exposed to time-varying RL loads dynamic load switching, and the performance is evaluated in real-time. OP 4510 real-time simulator verifies the proposed system's dynamic model created using Matlab/Simulink.

Auxiliary-ejector-based hydrogen recirculation system to broaden PEMFC operating range

This study presents an auxiliary-ejector-based hydrogen recirculation system to widen the operating range of the proton exchange membrane fuel cell system (PEMFCS). An auxiliary ejector (BE) design model is presented and then an experimentally verified two-dimensional numerical-simulation model is built to study the relationships between PEMFC output power, ejector geometrical parameters, and its performance (μ) based on sensitivity analysis. Finally, the operating characteristics of the BE are clarified. The results show that the μ is highly sensitive to position (Lb), followed by width (w) and angle (A) of auxiliary port. The BE can provide satisfactory μ above 0.8 under higher power output, and a μ higher than 0.6 for lower power output with the Lb, A, and w of 1.1, 30°, and 4 mm when PEMFCS works from 17.9 to 84 kW. This proposed system can extend the operation range of PEMFCS using a single ejector, which can contribute to fuel cell development.

Performance investigation on the bypass ejector for a proton exchange membrane fuel cell system

The poor entrainment performance of the conventional ejector is a significant problem that makes it hard to use in proton exchange membrane fuel cell (PEMFC) systems. This study aims to evaluate the entrainment performance of a bypass ejector for a 100 kW PEMFC system. The effects of three critical geometric parameters, namely the axial position, width, and angle of the bypass inlet, on the entrainment performance are thoroughly investigated. The results demonstrate that the bypass flow exhibits a significant performance improvement in the critical mode. In contrast, the performance improvement is negligible and even negative in the subcritical mode. After careful evaluation of the entrainment performance across various stack powers, the optimal axial position, width, and angle of the bypass inlet are found to be 1.1, 2 mm, and 10°, respectively. A comparative analysis between the bypass ejector and the conventional ejector underscores a significant advantage for the former, exhibiting a remarkable 22.1 % increase in the hydrogen entrainment ratio at the stack power of 101 kW. Nevertheless, the entrainment performance of the bypass ejector diminishes when operating at low stack powers below 24 kW.

Condensation and droplet characteristics in hydrogen recirculation ejectors for PEM fuel cell systems

The hydrogen recirculation ejector plays a pivotal role in proton exchange membrane fuel cell systems. Nevertheless, a comprehensive grasp of the intricate two-phase flow characteristics within hydrogen recirculation ejectors remains elusive. This investigation delves into the condensation and droplet behaviors of an ejector designed for a 100 kW fuel cell stack. The analysis relies on a two-phase flow model that takes into account both homogeneous and heterogeneous condensation. The findings reveal that homogeneous condensation nuclei manifest within the mixing chamber when the stack power surpasses 31 kW. The average median diameter of homogeneous droplets at the ejector outlet measures 0.367 μm, whereas that of heterogeneous droplets stands at 1.265 μm, signifying a 26.5 % augmentation compared to their initial size. Additionally, two crucial factors impact droplet size: residence time and subcooling degree. At the 100 kW condition, the droplet residence time is a mere 0.272 ms, yielding a meager droplet flow rate of merely 1.79 mg/s. In contrast, at the 53 kW condition, the downstream of the mixing chamber exhibits the maximum subcooling degree, resulting in the maximum droplet flow rate of 22.12 mg/s. A temperature elevation of 2.68 K at the ejector outlet is observed due to the latent heat of condensation. Furthermore, condensation has a marginal impact on the entrainment ratio, with the most significant reduction being 4.18 %, averaging at 1.42 %.

A novel energy storage system for efficiency improvement of fuel cell electric vehicles based on a new high step-up DC-DC converter

Proton exchange membrane fuel cell systems have relatively low efficiency in low power applications and have many uncertainties. In this regard, the design of a high-efficiency battery charger for fuel cell electric vehicles has been an important issue for researchers and has attracted a lot of attention in recent years. For this purpose, in this article, in the first step, with the aim of developing a battery charger with high efficiency and low cost, a new high step-up DC-DC converter with unique features is proposed. The main advantages of the proposed converter are continuous input current, high efficiency, low voltage stress on components, less component count, and high voltage gain. To prove the advantages of the proposed converter, a peer-to-peer comparison with some existing converters has been made and results are presented. In addition, this study comprehensively presents the different operating modes for the proposed converter and provides the necessary analysis and relationships for circuit operation. In the second step, this study explains the small signal modelling for the proposed converter as well as the maximum power point tracking controller for this system. In order to validate the proposed system, the values of theoretical calculations, simulation results, as well as the experimental results of the 48V-input/220V-output prototype device are presented and the results are compared side by side.

Improving a Fuel Cell System’s Thermal Management by Optimizing Thermal Control with the Particle Swarm Optimization Algorithm and an Artificial Neural Network

The thermal management of proton exchange membrane fuel cell systems plays a significant role in a stack’s lifetime, performance, and reliability. However, it is challenging to manage the thermal system precisely due to the multiple coupling relationships between the stack’s components, its operating environment, and its thermal management system. In addition, temperature hysteresis (temporal inconsistency of temperature with electrochemical reactions and fluid mechanics) imposes more difficulties on thermal control. We aim to develop an effective thermal control model for the fuel cell system to improve the temperature regulation accuracy and response speed and thus achieve highly stable temperature control. A dynamic mechanistic model is first developed based on the physical processes of the stack and its thermal management system. The model is then validated through experiments. Based on this dynamic mechanistic model, a control model is proposed for stack thermal management with the particle swarm optimization algorithm and an artificial neural network. It is applied and compared with the traditional PID algorithm. The simulation results indicate that the regulation time of the coolant inlet temperature as the current changes is reduced by more than 74%, and the overshoot is reduced by more than 50%. Therefore, the control model can enhance the dynamic response capability and temperature control precision under complex operating conditions with constantly changing load current and preset stack temperature, ensuring the temperature’s stability and thus improving the fuel cell system’s reliability and durability.

Optimization of hydrogen ejector structure in proton exchange membrane fuel cell system under wide operating conditions

ABSTRACT Considering the characteristics of the hydrogen ejector for proton exchange membrane fuel cell system used in vehicles, with the aim of expanding the operating range, the ejector structure parameters are comprehensively analyzed and optimized. The results indicate that reducing the throat diameter can expand its operating range. When the working conditions change significantly, the convergent nozzle should be selected, the convergence length and throat length of the nozzle have little effect on the ejection performance. There are optimal suction chamber convergence length (8 mm), diffuser divergent angle (7.1°) and length (33.8 mm), nozzle exit position (−7 mm) in variable working conditions to achieve good ejection performance. Reducing the diameter and length of the mixing chamber is beneficial for expanding the operating range. Before ejector optimization, when the primary fluid mass flow rate is less than the design value, the ejection performance deteriorates sharply with the decrease of the flow rate. When the primary fluid mass flow rate is lower than 0.4 g/s, the non-optimization ejector is backflow, the maximum ejection ratio is about 1.8 and the maximum hydrogen ejection ratio is about 0.67 in the operating range. After optimization, the ejector performance is stable. Under the set operating conditions, the hydrogen ejection ratio is greater than 0.75, the maximum ejection ratio is 3.8, and the maximum hydrogen ejection ratio is 1.01.

Control strategy for the anode gas supply system in a proton exchange membrane fuel cell system

Stable pressure control can improve the lifespan, efficiency, and stability of proton exchange membrane fuel cell system (PEMFCs). We successfully implemented a feedforward-based proportion-integral controller (FPIC) to control the anode pressure of a 100 kW fuel cell system. The bench experimental results demonstrate that the fuel cell stack achieves a maximum efficiency of 62.3 %, while the fuel cell power generation system achieve a maximum efficiency of 53.5 %. Under the steady-state and dynamic conditions, the strategy achieves a pressure tracking control accuracy of 98.93 % and 94.47 %, respectively. To address the large overshoot phenomenon and slow response speed of the FPIC when controlling the anode pressure, we further design a second order active disturbance rejection controller (SOADRC). The simulation results show that the SOADRC exhibits higher control stability and lower overshoot than FPIC. Moreover, it demonstrates a 51.3 % increase in response speed and an 80.7 % improvement in control stability under steady-state conditions compared to FPIC. The evaluation metrics for the error integral criterion (eISE = 0.023, eITSE = 2.58, eIAE = 0.35, and eIEAE = 36.76) are lower than FPIC, which demonstrates that the SOADRC provides more precise control of anode pressure, and enhances the stability of PEMFCs.

Fault diagnosis method for proton exchange membrane fuel cell system based on digital twin and unsupervised domain adaptive learning

In recent years, supervised deep learning-based methods have achieved significant results in fuel cell system fault diagnosis. However, most existing deep learning-based fault prediction methods suffer from missing fault labels and data limitations due to the difficulty in obtaining fault and degradation data in real fuel cell systems. To address the above challenges, this paper proposes a fault diagnosis method based on digital twin and unsupervised domain adaptive learning. The method has two key features: First, a maximum-relevance minimum-redundancy algorithm is used to select the input signals. Then a high-order fuel cell system model is developed to obtain a large amount of digital domain fault data at low cost by simulating fault injection. Second, domain-invariant features are extracted using a domain-adaptive adversarial learning approach to reduce the distribution differences between the digital and real domains. The method successfully diagnosed nine typical faults in the fuel cell air, hydrogen, and thermal subsystems without real data fault labels. Under dynamic load conditions, the diagnostic accuracy reached 92.5 %. In addition, the method achieves a diagnostic accuracy of over 90 % under domain adversarial training using only normal real data. The experimental results show that the proposed method can achieve fuel cell system fault diagnosis without fault labels and significantly reduce the dependence on fault data.

Mobile Proton-Exchange Membrane Fuel Cell Powered by Diesel Fuel: System Simulation and Life Cycle Analysis

Diesel engine generators used at construction sites generate noise, vibration, and large amounts of pollutant emissions. With the strengthening of emission standards for construction equipment, technologies must be developed to meet new requirements. We proposed and analyzed a mobile proton-exchange membrane fuel cell diesel-powered system to address these issues. The proposed system consisted of an autothermal reformer, a proton-exchange membrane fuel cell, and a balance of plant components. Previous studies on the system have not explored the optimal design and operating condition of the system and have not shown whether the proposed system is superior to the system using the hydrogen-fueled proton-exchange membrane fuel cell system in the life-cycle greenhouse gas emissions point of view. In this study, we clarified system operation characteristics, determined the operational design point, and evaluated system performance and life-cycle greenhouse gas emissions. The system was analyzed by constructing a zero-dimensional simulation model. Several control parameters were varied in parametric studies to determine the operational design point (steam-to-carbon ratio of 2, oxygen-to-carbon ratio of 0.5, fuel utilization factor of 0.85, and heat exchanger effectiveness of 0.85). Considering system performance, the determined design point achieved a 32.3% efficiency. Additionally, we assessed the life-cycle greenhouse gas emissions of the system and compared them with those of an alternative system, which is a hydrogen-fueled proton exchange membrane fuel cell system. It was confirmed that in the United States of America, the proposed system emits 1010.2 g-CO2-eq/kWh of greenhouse gas at a 300 km fuel transportation distance, which is similar to a hydrogen-fueled proton-exchange membrane fuel cell system (1001.1 g-CO2-eq/kWh). The proposed system emits less greenhouse gas emissions than the hydrogen-fueled proton-exchange membrane fuel cell system if the distance from the hydrogen production site to the construction site is more than 318 km. Therefore, for a construction site far from a hydrogen production plant, the proposed diesel-fueled proton-exchange membrane fuel cell system is preferable from both the greenhouse gas emissions and convenience perspectives.

Research on Power Control Strategy of Automotive Fuel Cell based on Sag Control and Fuzzy Logic

Fuel cell vehicles powered by proton, exchange membrane fuel cell systems. They have gained widespread attention for their unique environmental advantages. Pure fuel cell system usually uses hybrid power system because of its soft output and slow dynamic response. The study takes the automotive fuel cell power system as the research object, designs a power control strategy based on DC voltage sag control and fuzzy logic and proves its effectiveness by simulation for different working conditions. The simulation results show that under CYC_UDDS conditions, the bus voltage curve of the power system changes smoothly and the voltage fluctuation range is 580~612V, which satisfies the 5% voltage accuracy. And the SOC of the battery is relatively smooth in the whole cycle condition, maintaining between 0.685 and 0.715. Its slightly increasing, which is in the line with the design goal of maintaining SOC of the battery near 0.7. The scheme proposed in the study helps to solve the problems of difficult design implementation, large number of calculations, poor real-time performance and complex structure of the current existing control strategies.

Multi-Objective sliding mode control of proton exchange membrane fuel cell system based on adaptive algebraic observer

To improve the efficiency and extend the lifespan of the proton exchange membrane fuel cells (PEMFC), it is imperative to control PEMFC’s supply system effectively. A sliding mode controller (SMC) based on adaptive algebraic observer is designed to control the oxygen excess ratio and the pressure difference between the cathode and anode of PEMFC. First, a 9th order physical model of the PEMFC system is established including air supply system, hydrogen supply system and the stack, which is validated against the experimental data with the maximum output voltage error of 2.91%. Then, a SMC is designed based on the control-oriented PEMFC model. An adaptive algebraic observer for the estimation of the gas partial pressure is designed to be used in the SMC. Finally, simulation is conducted and results show that the performance of the designed SMC is superior than that of the PID controller in terms of the oxygen excess ratio settling time (1s less), the pressure difference settling time (50% less) and overshoot (0.5 kPa less).

Observer design based on D-stability and Finsler’s lemma for interconnected Takagi–Sugeno systems with immeasurable premise variables

This paper deals with the observer design for a class of Interconnected Takagi–Sugeno (TS) systems with Immeasurable Premise Variables (IPV). We first investigate the D-stability of Luenberger-like interconnected multiple observers. However, the resulting constraints can be somewhat conservative due to the use of a common Lyapunov matrix. Then, the so-called Finsler’s lemma is used to relax the D-stability conditions through the introduction of additional slack variables providing more flexibility and extra degrees of freedom. The designed conditions are expressed as Linear Matrix Inequalities (LMIs). The proposed approaches are applied in simulation to a Proton Exchange Membrane Fuel Cell (PEMFC) system and a four-tank system.