Fuel Cell Stack Research Articles

Power Management Strategy of a PEM Fuel Cell-Battery Powered Electric Vehicle

A MATLAB-Simulink based mathematical vehicle simulation model is developed in this investigation to analyze power management strategy of a proton exchange membrane (PEM) fuel cell and battery powered electric vehicle. The vehicle simulation model incorporated a real-world commercial passenger vehicle operator’s drive cycle inputs and associated vehicle dynamics to determine accurate estimation of total onboard power requirements and withdrawal of power from the fuel cell and battery sources to meet the demand. The power management strategy is designed to meet the vehicle’s onboard power demand based on the availability of hybrid combination of fuel cell and battery power sources. The fuel cell stack is the primary power source of the vehicle. The fuel cell is also charging the battery with excess power produced onboard and hence controls the state-of-charge of the battery. Battery is used as a supplemental power source for meeting the vehicle’s peak power demands. The parameters are optimized to implement the power management strategy by considering the battery state-of-the charge, the drive torque and the vehicle drive performance. The model simulation results with optimized parameters showed that the power requirement of the electric vehicle was significantly affected by the combination of fuel cell and battery power management system as well as the operating behaviors of the end user (driver).

Craft Brewery Wastewater Treatment in a Scalable Microbial Fuel Cell Stack

Craft breweries release wastewater into the environment, posing serious environmental concerns. Microbial fuel cells (MFCs) are an attractive technology that has been used in industrial wastewater treatment. This study used a scalable system of nine MFCs (stacked) to treat 150 L of craft brewery wastewater (CBW). The CBW had 1831 ± 85 mg COD (chemical oxygen demand) L−1. The hydraulic retention time was 5 days, with a COD removal percentage of 93 ± 1.8%. The total internal resistance of the stack was 204.8 ± 5.2 Ω at 26 ± 2 °C without the use of a metal catalyst; the reduction of oxygen was the limiting process. Finally, the sequence of treatments applied with this proposed system demonstrated its self-sustainability, which could be a viable option for the real-life conditions of this kind of wastewater. Further research is needed.

Rapid activation of proton exchange membrane fuel cell stack and underlying mechanisms involved

Activation is a crucial procedure to improve the performance of newly fabricated fuel cell stacks to meet the power requirements in actual application scenarios. However, traditional activation procedures generally last for several hours or even days, which greatly increases the cost and limits the production efficiency. In response to this problem, this paper proposes a rapid activation procedure composed of hydrogen pumping (HP) and limiting-current activation with limited air (LCA). The influence of current density for HP and air supply for LCA on activation effect is studied and the best operating conditions are determined. The importance of water supply to the cathode is highlighted during HP. The influence of air supply for LCA on activation effect is limited, which contributes to gas saving. According to the experiments conducted on a single cell and a 10-cell stack, only 40 min are needed with this combined procedure, which is much shorter than that of the traditional step-current activation. Furthermore, nearly 75% of hydrogen is saved due to the short activation time and the control of gas supply, thus significantly reducing the cost during activation. Furthermore, to reveal the underlying mechanisms, membrane electrode assembly parameters before and after activation are obtained by micro-current excitation. A decrease in ohmic resistance and an increase in roughness factor of catalyst are observed, which contribute to performance improvement. According to the characterizations in the microstructure of membrane electrode assembly and platinum catalyst valence state, the electrolyte hydration and oxide reduction are determined as key factors and principles during activation.

Development of a smart powering system with ammonia fuel cells and internal combustion engine for submarines

The current limitations of hydrogen storage technology in submarines have prompted the need for alternative solutions. One promising option is the use of ammonia, a readily stored fuel. This paper presents an innovative, integrated system that runs on ammonia and does not rely on atmospheric air. The system combines Direct Ammonia Fuel Cell (DAFC) stack and an Internal Combustion Engine (ICE) technology to generate power, freshwater, and cooling. The system also recovers waste heat and utilizes it efficiently to produce these useful outputs. The study further aims to assess the system's performance using energy and exergy analysis methods and to conduct a parametric analysis to examine the impact of parameters and operating conditions on system efficiency. In the developed integrated system, the quantities of net power produced, cooling provided, and freshwater flow rate produced under specified conditions are 4069 kW, 589.5 kW, and 1.269 kg/s, respectively. Its energy and exergy efficiency were found to be 38.58% and 44.77%, respectively. The analysis study also obtains that increasing the ammonia flow rate supplied to the ICE and the steam flow rate provided to the turbine, as well as the reference temperature, could potentially improve both energetic and exergetic efficiencies.

Towards suitable practices for the integration of social life cycle assessment into the ecodesign framework of hydrogen-related products

The hydrogen sector is envisaged as one of the key enablers of the energy transition that the European Union is facing to accomplish its decarbonization targets. However, regarding the technologies that enable the deployment of a hydrogen economy, a growing concern exists about potential burden-shifting across sustainability dimensions. In this sense, social life cycle assessment arises as a promising methodology to evaluate the social implications of hydrogen technologies along their supply chains. In the context of the European projects eGHOST and SH2E, this study seeks to advance on key methodological aspects of social life cycle assessment when it comes to guiding the ecodesign of two relevant hydrogen-related products: a 5 kW solid oxide electrolysis cell stack for hydrogen production, and a 48 kW proton-exchange membrane fuel cell stack for mobility applications. Based on the social life cycle assessment results for both case studies under alternative approaches, the definition of a product-specific supply chain, making use of appropriate cut-off criteria, was found to be the preferable choice when addressing system boundaries definition. Moreover, performing calculations according to the activity variable approach was found to provide valuable results in terms of social hotspots identification to support subsequent decision-making processes on ecodesign, while the direct calculation approach is foreseen as a complement to ease the interpretation of social scores. It is concluded that advancements in the formalization of such suitable practices could foster the integration of social metrics into the sustainable-by-design framework of hydrogen-related products.

Effects of Inhomogeneous Gas Diffusion Layer Properties on the Transportation Phenomenon and Performances of Proton-Exchange Membrane Fuel Cells.

The encapsulation of the proton-exchange membrane fuel cell (PEMFC) is an essential step of fuel cell stack assembly. The selection of the assembly pressure is very important to the stack performance and life. Based on that, this paper presents a method to describe the internal physical deformation of the gas diffusion layer (GDL) after inhomogeneous pressure by using user-defined functions (UDFs). The results show that the transmission difference caused by the nonuniform GDL deformation can be clearly seen by the UDFs method, and there is an obvious transition of GDL at the interface of the channel and the rib. A three-dimensional single-channel PEMFC model is established, and an optimal assembly pressure range is obtained, between 1.5 and 2.0 MPa. The maximum thermal stress inside the cell occurs in the middle of the membrane electrode assembly and decreases as the assembly pressure increases. Furthermore, the influence of rib-channel ratios is discussed. Compared to the fuel cells with ratios of 2:1, 2:3, and 1:2, the one with 1:1 exhibits the maximum current density and the highest power density.

Enhancing fuel cell performance through a dual MPC strategy for coordinated temperature management

Ensuring the optimal operating temperature is imperative for achieving efficient performance in proton exchange membrane fuel cells. Consequently, this study introduces a dual-model predictive control strategy to regulate the water pump and cooling fan in a cooling system. Initially, we establish an electrochemical and thermal model for fuel cell stacks and validate the model’s accuracy through experimental data. The system model is linearized, and the model predictive control (MPC) controller is formulated using the MATLAB/Simulink toolbox. Subsequently, it is collaboratively simulated with the electrochemical model of the fuel cell stack and the temperature model. To evaluate the effectiveness of the MPC controller, we conducted a comparative analysis with the traditional proportional–integral–derivative (PID) control and water pump MPC under step load, uniform load increase, and variable target scenarios. The findings indicate that in contrast to the PID control, the MPC controller significantly decreases the stack temperature difference fluctuation by more than 50%, maintaining the stack temperature within ±0.6 K of the set value. Furthermore, we independently assessed the performance of the MPC controller under varying ambient temperatures. The findings illustrate that the dual MPC method proficiently adapts cooling parameters across different ambient temperature ranges (288.15 K–308.15 K), ensuring the stable performance of the fuel cell. The model is linearized, and the simulation work is explained mainly on the MATLAB/Simulink platform. In order to compare the effectiveness of the MPC controller, the comparison with the MPC controller strategy of the water pump is added, which can better reflect the effectiveness of the proposed collaborative MPC controller strategy.

Effect of Crown Ether Additives on the Enhanced Performance of Metallic Bipolar Plates for Proton Exchange Membrane Fuel Cells.

One of the key components of the fuel cell stack is a metallic bipolar plate (MBP) that plays multiple roles, such as current collector, fuel and oxidant distributor, and mechanical support. However, corrosion and consequent metal elution are major drawbacks of the MBP because they diminish the efficiency and power performance of membrane-electrode assemblies (MEAs). Herein, we show that the crown ether (CE) additive can simultaneously inhibit surface corrosion of the MBP and act as a scavenger for eluted metal ions to alleviate contamination of other components. From the electrochemical measurement, high-resolution imaging, and elemental analysis, we have found that the CE undergoes electrolytic decomposition and makes an efficient protective layer in an in situ manner. This layer prevents direct contact between the MBP and electrolyte as well as the dissolution of metal ions into the electrolyte. In addition, we demonstrate that the CE can improve the recovery protocol of the MEA owing to the formation of host-guest complexes between the CE and metal cations. These results provide key insights into the design of high-performance MBPs for proton-exchange membrane fuel cells.

Data Driven Model for a Fuel Cell stack development in a complex Multi-source Hybrid Renewable Energy System

Fuel cells based on polymer electrolyte membrane are considered as the most hopeful clean power technology. The operating principles of polymer electrolyte membrane fuel cells (PEMFC) system involve electrochemistry, thermodynamics and hydrodynamics theory for which it is difficult to establish a mathematical model. In this paper a nonlinear data driven model of a PEMFC stack is developed using Neural Networks (NNs). The model presented is a black-box model, based on a set of measurable exogenous inputs and is able to predict the output voltage and cathode temperature of a high power module working at the CNR- ITAE. A 5 kW PEM fuel cell stack is employed to experimentally investigate the dynamic behaviour and to reveal the most influential factors.

The effect of CaO/MgO content on properties of barium aluminosilicate sealants for solid oxide fuel cells

Design of an appropriate sealant is crucial for reliable sealing and stable long-term operation of solid oxide fuel cells. We have investigated sealants based on barium aluminosilicate glass-ceramic modified with CaO and MgO. Focus of the research was on the 0.33BaO-0.20XO-0.33SiO2–0.05Al2O3–0.09B2O3 system, where XO is CaO, MgO, or a mixture of the two. Key properties of the system were studied, and its applicability of different compositions to sealing of high-temperature solid oxide fuel cells was investigated. Thermal properties, such as softening point and a half-ball point of the glass, coefficients of thermal expansion and adhesion to Crofer 22APU steel were of primary concern. CaO-containing sealants of this system showed much lower softening point compared to that of MgO-containing sealants. The substitution of CaO with MgO had no detectable effect on the coefficients of thermal expansion of the sealants. The coefficients of all the studied compositions were in 11.2–11.6∙10−6 1/K range. All the compositions have good adhesion to both Crofer 22 APU steel and ZrO2-based electrolyte. CaO-containing sealant was tested under operation conditions of a fuel cell stack for ten days; the seal remained hermetic for that period with no visible signs of degradation or oncoming failure of the seal.

Fuel cell stack design and modelling with a double-stage boost converter coupled to a single-phase inverter

Abstract A comprehensive proton-exchange membrane fuel cell stack model was developed and integrated with a two-stage DC/DC boost converter. It was directly coupled to a single-phase (two levels—four pulses) inverter without a transformer. The pulse-width modulation signal was used to independently regulate every converter phase. The converter was modelled using a MATLAB®/Simulink® environment and an appropriate voltage control method. The analysis features of the suggested circuit were created and, through established experiments, the simulation results were verified. A single-phase (two levels—four pulses) inverter control circuit was tested and it produced a pure sinusoidal waveform with voltage control. It matches the voltage of the network in terms of amplitude and frequency. A sinusoidal pulse-width modulation approach was performed using a single-phase (two levels—four pulses) pulse-width modulation inverter. The results demonstrated an enhancement in the standard of the output wave and tuned the dead time with a reduction of 63 µs compared with 180 µs in conventional techniques.

Bond graph model of a PEM fuel cell stack

The fuel cell is a complex system, in which several disciplinary fields are concerned: hydraulics, chemical, thermal and electric. In this paper, we present the hydraulic part of the model of a PEM fuel cell stack via the Bond Graph formalism. The developed model enables to simulate the pressure losses inside the fuel cell. Firstly the basis of Bond Graph modelling is recalled. Then, the structure of the model and its elements are described. Secondly, the model is exploited to study the effects of operating conditions on the pressure losses attached to the distribution of gases in the electrodes.

An Electrochemical Performance Model Considering of Non-Uniform Gas Distribution Based on Porous Media Method in PEMFC Stack

Proton exchange membrane fuel cell (PEMFC) is significant and favorable to the long-range and short refueling time in the vehicle industry. However, the non-uniform distribution of gas flow supply, particularly in the fuel cell stack is neglected in the electrochemical model for PEMFC performance optimization. The purpose of this study is to break through this limitation to establish an optimized electrochemical fuel cell performance model, with porous media methods considering the non-uniform gas flow distribution in fuel cell stack with different compression of the gas distribution layer (GDL). The numerical models are validated by experimentation of a practical fuel cell stack. For the established fuel cell model, there is a 5% difference between the maximum and minimum speeds of various flow channels in the anode flow field under 10% GDL compression. Furthermore, the single-channel electrochemical performance model is optimized by considering the non-uniform gas flow distribution of the fuel cell stack. The results of the optimized electrochemical fuel cell performance model demonstrate that the correlation coefficient between the experiment results and the simulation results is nearly 99.50%, which is higher than that of the original model under 20% GDL compression. This established model is effective in enhancing the prediction accuracy of the PEMFC performance.

A methodology to develop multi-physics dynamic fuel cell system models validated with vehicle realistic drive cycle data

Fuel cell (FC) technology has been identified as a technically attractive solution to decarbonize the transportation sector, especially for heavy-duty vehicles. In this context, the industry and the scientific community are in need of advanced fuel cell systems (FCS) models that are able to replicate real-world operating conditions. Due to the scarcity of said models in the open literature, this study aimed to develop a comprehensive methodology to calibrate and validate multi-physics dynamic FCS models. Therefore, the key contribution of this paper is the detailed description of the calibration process for each component and the calibration order. The specific focus here was to accurately describe the behavior of the FC stack as well as the cathode, anode, and cooling circuits of the balance of plant. The model was calibrated with the aid of experimental data from a Toyota Mirai FC electric vehicle, which was predominantly retrieved from the vehicle’s Controller Area Network (CAN) bus system thereby negating the need for major intrusion into the powertrain system. The validation process was deemed successful with the model being able to truthfully replicate the characteristics of the FC vehicle operated on the World-wide harmonized Light duty Test Cycle (WLTC) 3b and US06 driving cycle. The time-resolved physical parameters such as the cathode pressure, mass flow, or the FC stack temperature were captured with high fidelity, while the overall performance parameters such as the H2 consumption in the stack and the system, and the compressor energy consumption were predicted accurately with a deviation lower than 0.47%, 1.75% and 1.89% with respect to the experimental data, respectively.

Efficiency improvement strategy of fuel cell system based on oxygen excess ratio and cathode pressure two-dimensional optimization

Improving the commercial fuel cell system efficiency is critical to reducing hydrogen consumption and improving the operational economy. This paper studies the power consumption pattern of the air supply subsystem, the most power-consuming auxiliary components, aiming to improve the system’s efficiency. A method was proposed to get the extremum of the system net power by optimizing the oxygen excess ratio and cathode pressure. Mathematical models describing the fuel cell stack and air supply subsystem power characteristics were developed based on the mechanism analysis and estimation of unknown parameters. Then, a system net power model for energy efficiency optimization was developed. The operating conditions for optimal efficiency at a specific current density can be obtained by numerical calculation. To verify the method’s effectiveness, a series of experiments were conducted, and the results show that the proposed method can maximize system net power output at various current density conditions. Compared with the conventional oxygen excess rate based one-dimensional optimization, the two-dimensional method can improve system efficiency by 2.06%, offering a good application prospect.

In-line measuring and feature similarity-based group and pairing assembly for metallic BPPs

Assembly of proton exchange membrane (PEM) fuel cell stacks with metallic bipolar plates (BPPs) is a process of high precision stacking for hundreds of individual sheet components. The accuracy of stacking process and the uniformity of contact status for layers effect the working efficiency of the stack. The manufacturing of metallic BPPs consists of several processes including pressing, welding and coating, in which each process will have an impact on the final shape of BPPs. Especially for large-scale metallic BPPs, which are critical parts for manufacturing high power fuel cell stack, the shape deviation will be magnified. In this research, a batch of normal size metallic BPPs are investigated as preliminary study for large-scale BPPs. They are measured by a 3D laser scanner and their geometric deviation are analyzed. An approach of in-line measuring integrated automatic assembly line for BPPs and a method of feature similarity-based group and pairing assembly are proposed with which the uncertainty of stacking result with random placing order of fuel cell components is expected to be reduced without changing previous manufacturing processes. The scanned features are compared to the nominal model of BPP and then fitted into surfaces to visualize the individual deviations. K-medoids algorithm is used to cluster these BPPs into groups. The result shows feasibility of applying this method to large-scale BPPs in future work.

Development of an Adaptive Human-centered Work Station for Fuel Cell Stack Assembly

Facing the challenges of modern production, such as increased product variability and individuality, assembly systems must strive for maximum flexibility. Consequently, despite the continuous advancements in automation, the human workforce retains its crucial role in industrial assembly due to its exceptional adaptability and learning capabilities. However, the industry is confronted with the additional challenge of addressing a shortage of skilled workers, managing ongoing demographic changes, and handling an increasingly heterogenous workforce in terms of age, skills, and experience. As a result, there is a growing emphasis on the efficient and ergonomic use of the human workforce. In this context, the concept of human-centered production systems has emerged as an important approach.The objective of this paper is to propose a general concept for the implementation of a human-centered assembly system that can adapt to different human characteristics in terms of anthropometry, functional capabilities, knowledge, and personal needs during the assembly process. This in-process adaptation is based on the tracking of human movements and actions during the assembly process using LiDAR and camera technology. The collected data is utilized to feed a recommender system that serves to suggest possible configuration optimizations in the assembly system dimensions of Working height, Range of vision, gripping area, and handedness, Lighting and Use of information and assistance systems, encompassing a laser projector, spatial augmented reality facilitated by a dynamic beamer, and intelligent tools.Subsequently this general approach is applied to the development of a work station designed for the assembly of fuel cell stack components.

TS-Fuzzy Controllers based Novel Control of Grid Connected Fuel Cell Stack System

TS-Fuzzy Controllers based Novel Control of Grid Connected Fuel Cell Stack System

The energy efficiency of an extended range unit involving a polymer exchange membrane fuel cell stack

This article presents the results of experimental investigations on an advanced model of a polymer exchange membrane fuel cell (PEMFC) stack designed to serve as a charging unit for electric vehicle batteries or off-grid distributed power sources. The assembled 720 W PEMFC stack comprises two 360 W modules that can be electrically connected in series or parallel. A liquid cooling system for the PEMFC stack has also been constructed. The dependencies – voltage (U) versus current (I) and current (I) versus electrical power (P) – for single modules, as well as for the electrically connected two-module PEMFC stack, are determined. Additionally, the hydrogen utilization versus the electrical power (P) of the PEMFC stack is examined. The electrical efficiency of the PEMFC stack varies between 42% and 50%, depending on the electrical power. An adjustable DC/DC converter, operating in two modes (step-down or stepup), is proposed as a device to integrate a lithium-ion (Li-ion) battery pack with approximately 720 W PEMFC stack. The electrical architecture of the integrated system, comprising the PEMFC stack, DC/DC converter, and Li-ion battery pack, is investigated and discussed in this paper. It was found that the electrical efficiency of the proposed DC/DC converter varies depending on the electrical power, reaching a peak efficiency of 95%– 98%. The environmental benefit, in terms of reducing CO2 emissions when charging the battery, was also identified.

Challenges in the Virtual Geometry Assurance of Proton Exchange Membrane Fuel Cell Stacks

Hydrogen-powered fuel cells will play a vital role in the next generation of energy systems. In this regard, Proton Exchange Membrane Fuel Cells (PEMFC) represent a promising technical solution for all applications where direct electrification is not technically feasible or economically viable, such as the propulsion of heavy vehicles. However, robust production of high-quality fuel cell systems in scalable series production can only be achieved by an early assurance of the product quality considering the numerous variations on geometry element, part, and assembly level. This article presents the challenges and outlines the vision of a geometry assurance process capable of simulating the probabilistic assembly behavior of PEMFC stacks by multi-physics variation simulation, e.g., considering aspects of Finite Element Analysis and Computational Fluid Dynamics, under a realistic representation of the part manufacturing and assembly processes and their operation under variations. The findings reveal future research directions fostering the series production of robust, high-quality PEMFC stacks.