PEMFC的Elman神经网络建模与模糊神经网络控制

从质子交换膜燃料电池（PEMFC）实际应用的角度出发，采用Elman动态神经网络对PEMFC系统进行建模，以实验中采样到的PEMFC系统的工作温度输入输出数据训练网络，并采用动态反向传播学习算法根据误差不断调整网络参数直至达到要求精度。设计了一种适应模糊神经网络控制器，根据经验确定了初始隶属度函数和模糊规则，并采用自适应学习算法不断调整隶属度函数与模糊规则参数，使控制系统获得理想的输出。仿真实验以Elman神经网络模型为参考模型，使用自适应神经网络控制算法取得了较好的控制效果。总之，所设计的控制系统适合于控制PEMFC这样一类复杂非线性系统。     

船体简谐振动下PEMFC气体扩散-电化学反应的动态响应

针对质子交换膜燃料电池（PEMFC）船舶适用性问题，建立船体简谐振动条件下三维单流道PEMFC计算模型，并以计算流体力学为主要研究方法，仿真研究PEMFC在船体简谐振动情况下的动态性能变化，并通过组分运输过程以及电化学反应对振动条件下PEMFC的动态响应进行内在机制解析。结果表明：简谐振动下PEMFC在经过初始阶段响应后，呈周期性输出规律；船体振动会显著影响PEMFC内部组分传热传质，导致电化学反应无法正常进行，PEMFC性能出现衰变趋势，甚至造成电池饥饿现象；当振幅不变时，振动频率的增大会加剧该现象。     

质子交换膜燃料电池可靠性分析

可靠性是质子交换膜燃料电池(PEMFC)的重要指标，文中定性分析了PEMFC组成元件、装配工艺和工作过程的可靠性。提出了提高PEMFC可靠性的措施和可靠性的设计原则。     

质子交换膜燃料电池及其在电动车上应用的现状

质子交换膜燃料电池（PEMFC）作为第四代发电技术的典型，具有高效和环境友好两大突出优点，受到世界各国政府的极大关注和各大汽车公司的青睐，现已进行了众多的PEMFC电动车开发项目，并将在不久的将来投入市场。PEMFC电动车前景灿烂。     

质子交换膜燃料电池(PEMFC)的建模方法研究

质子交换膜燃料电池（PEMFC）是21世纪最有生命力的发电技术之一。参考大量文献，总结出PEMFC建模的基本方法。从电化学、液体动力学角度出发，全面地分析三维PEMFC数学模型，其具普遍意义。并阐明遗传算法、神经模糊控制技术在PEMFC控制方面的应用。     

质子交换膜燃料电池

因其具有独特的优点，质子交换膜燃料电池（PEMFC）的市场前景很好，国际上已经形成了一股研究开发热潮。电催化剂、质子交换膜、双极板、燃料、水管理、热管理是质子交换膜燃料电池的关键技术。文章介绍了PEMFC的特点及开发应用状况，综述了PEMFC的研究进展。     

新型拓展流道PEMFC传质模拟与性能研究

该文提出一种带有拓展区域的新型PEMFC流道，拓展区域长度分别设计为1、2和4 mm。采用COMSOL软件建立三维等温稳态模型并进行数值计算。结果表明：新型拓展流道PEMFC性能均优于传统直流道PEMFC，其最佳拓展长度为2 mm。在高电流密度下，拓展流道使氧气分布更加均匀，提升水的去除能力。当取最佳拓展长度时，增加拓展区域数量能进一步提升燃料电池性能，与传统直流道相比，双拓展区域的流道使PEMFC峰值功率密度提高了18.44%。     

质子交换膜燃料电池系统控制与应用现状

描述了质子交换膜燃料电池(PEMFC)系统的控制及其在中低功率领域中的应用现状。首先概述了过程模型和电压预测模型，对影响电堆性能的各参数进行分析。其次，从目前运用的简单控制方法、混合动力驱动、效率优化、故障容许等方面对PEMFC系统的分析与控制结构作了说明。然后介绍了PEMFC的几种具体应用。最后结合国内外的相关研究进展，提出了一些有待进一步研究的方向。     

发挥山西煤基甲醇原料优势生产清洁型车用醇醚燃料

以煤基甲醇为原料，经气相脱水醚化产出醇醚烃混合物用于改善车用燃油的使用性能和排放特性，解决了目前掺混型甲醇汽油、甲醇柴油存在的一些问题。     

外界供给参数对PEMFC输出性能及水热平衡的影响

为了改善质子交换膜燃料电池(PEMFC)内部的水热平衡,从而进一步改善PEMFC的输出性能,文章建立了PEMFC的三维模型,通过改变PEMFC的外界供给参数(进气速度、加湿率以及冷却水流速),应用COMSOL模拟仿真得到了PEMFC的极化曲线和功率曲线、流道和气体扩散层(GDL)的水浓度分布情况,以及冷却水流速对PEMFC温度的影响。研究结果表明:随着进气速度和加湿率的逐渐增加,PEMFC的输出性能均逐渐提升,但是,过高的加湿率可能导致电极水淹;随着冷却水流速的增加,PEMFC温度加速下降,膜内温度分布变得更均匀。     

In situ diagnostics for water transport in proton exchange membrane fuel cells

Proton exchange membrane fuel cells (PEMFCs) have attracted considerable attention as energy-conversion systems for future applications in vehicles and for on-site power generation. Major technical challenges exist in achieving a high cell performance over a wide range of operating conditions, such as various cell current densities, operating temperatures, and relative humidities of the supplied gases. Correct water management is critical to achieving a high power density, long-term operation, and increased robustness in PEMFCs. Aspects such as the swelling of the membrane by water, the generation and accumulation of liquid water inside the fuel cells, and the discharge of accumulated water need to be clarified to ensure a fundamental understanding of water transport in PEMFCs. In this article, we examine the state of art regarding in situ diagnostics, particularly visualization techniques, for probing the behaviour of water in PEMFCs, with attention to neutron radiography, X-ray imaging, magnetic resonance imaging, and optical visualization techniques. The recent rapid development of in situ imaging techniques with high spatial and temporal resolutions provides a novel platform for the development of PEMFCs.     

Fractional order model for diagnosis of flooding and drying of the proton exchange membrane fuel cell

The diagnosis and control of PEMFCs hydration states depend on the reliable models and methods of monitoring of system operating. Impedance spectroscopy was generally used to describe fuel cell systems and derived impedance models. This study investigated the characterization and diagnosis of fuel cells by using fractional order impedance model as an explicit transfer function and factor design methodology (DOE) to determine the model parameters. The physical parameters appeared very sensitive to humidity and then used for monitoring and diagnosing of fuel cells. The proposed model is suitable to represent Randles impedance model equivalent electrical circuit enhanced by CPE, with the ability to generate the Nyquist impedance spectra easily for all conditions of relative humidity and operating time.The comparison between the literature experimental impedance spectra in both cases (drying and flooding), and the spectra simulated by the explicit fractional order impedance model demonstrated that the proposed model was robust and reliable and can, therefore, be integrated into the PEMFCs water management system.     

Microstructured membranes for improving transport resistances in proton exchange membrane fuel cells

Proton exchange membrane fuel cells (PEMFCs) have been identified as one of the most promising renewable energy system for use in automotive applications. However, due to the wide range of weather conditions around the world, the PEMFCs must be stable for operating under these variable conditions. One of the inefficiencies of PEMFCs in automotive applications is during vehicle warm-up, where the low hydration level within the PEMFC can lead to a low performance of the fuel cell. In this study, a proton exchange membrane (PEM) was prepared with regular, microstructured features tuned over a range of aspect ratios. These microstructured membranes were incorporated into MEAs and analyzed for their membrane, proton, and oxygen transport resistances. These fuel cells were tested under different conditions to simulate vehicle start-up, normal operating conditions, and hot operating conditions. It was determined that microstructured PEMs improved performance over planar PEMs under both the start-up and hot conditions. Despite the improved performance of the microstructured PEMs, a high hydrogen cross-over and short-circuit current were also observed for these samples. Adjusting the preparation techniques and tuning the dimensions of the microstructures may provide avenues for further optimization of PEMFC performance.     

Electrolytes for solid oxide fuel cells

The high operating temperature of solid oxide fuel cells (SOFCs), as compared to polymer electrolyte membrane fuel cells (PEMFCs), improves tolerance to impurities in the fuel, but also creates challenges in the development of suitable materials for the various fuel cell components. In response to these challenges, intermediate temperature solid oxide fuel cells (IT-SOFCs) are being developed to reduce high-temperature material requirements, which will extend useful lifetime, improve durability and reduce cost, while maintaining good fuel flexibility. A major challenge in reducing the operating temperature of SOFCs is the development of solid electrolyte materials with sufficient conductivity to maintain acceptably low ohmic losses during operation. In this paper, solid electrolytes being developed for solid oxide fuel cells, including zirconia-, ceria- and lanthanum gallate-based materials, are reviewed and compared. The focus is on the conductivity, but other issues, such as compatibility with electrode materials, are also discussed.     

Water quality and yield from polymer electrolyte membrane fuel cells

Water and energy production and demand are interconnected. Polymer electrolyte membrane fuel cells (PEMFCs) are devices that produce water while they generate power using hydrogen as a fuel. Herein, a lab-scale PEMFC was operated under variable experimental conditions, such as membrane chemical composition, operating temperature, operating current density, external humidification water quality, and fuel cell materials, to investigate the quality and quantity of the water produced. At each experimental condition the quantity and quality of the recovered product water was evaluated in the context of its suitability for use as drinking water. The results indicate that water produced by PEMFCs needs some treatment to comply with the US Environmental Protection Agency (US EPA) drinking water standards and World Health Organization (WHO) guidelines for drinking water quality. The measurements show a correlation between the fluoride concentration and the total organic matter (TOC) in the water samples when the fuel cell is operated with self-humidified membranes. A water collection efficiency up to 70% was obtained.     

Tolerance and mitigation strategies of proton exchange membrane fuel cells subject to acetylene contamination

Acetylene contamination in proton exchange membrane fuel cells (PEMFCs) significantly depends on cell operating conditions. In this work, acetylene contamination is studied by varying the acetylene concentration, cathode potential and temperature. Hysteresis in the cell performance response is observed during cycling tests with variations in acetylene concentration and cathode potential and is attributed to the potential dependency of acetylene redox reactions. The tolerance of PEMFCs to acetylene is established at approximately 23 ppm for a commercially available catalyst-coated membrane. For a cell poisoned by acetylene at a concentration above the tolerance value, performance losses are eliminated by bringing the ohmic compensated cell voltage into the acetylene oxidation (cell voltage increase) or hydrogenation (cell voltage decrease) regions.     

A review on water balance in the membrane electrode assembly of proton exchange membrane fuel cells

Water balance has been proven to be critical not only for the performance but also for the durability of proton exchange membrane fuel cells (PEMFCs). This paper reviews experimental investigations and modeling works on water transport and balance in different constituents of the membrane electrode assembly (MEA), which is the most important component determining the performance and durability of a PEMFC. Major water transport mechanisms in the membrane and porous layers of MEA are summarized and the strategies to balance water in these components are also discussed. However, the experimental water transport data for different components under varied operating conditions are still insufficient and the understanding of transport mechanisms is still limited. To obtain better water management in PEMFCs, the design of the key components requires refinements. For future investigations more attention should be paid to the fundamental understanding and systematic data of water transport in each component of the MEA under varied operating conditions.     

Experimental factors that influence carbon monoxide tolerance of high-temperature proton-exchange membrane fuel cells

The poisoning effect of carbon monoxide (CO) on high-temperature proton-exchange membrane fuel cells (PEMFCs) is investigated with respect to CO concentration, operating temperature, fuel feed mode, and anode Pt loading. The loss in cell voltage when CO is added to pure hydrogen anode gas is a function of fuel utilization and anode Pt loading as well as obvious factors such as CO concentration, temperature and current density. The tolerance to CO can be varied significantly using a different experimental design of fuel utilization and anode Pt loading. A difference in cell performance with CO-containing hydrogen is observed when two cells with different flow channel geometries are used, although the two cells show similar cell performance with pure hydrogen. A different combination of fuel utilization, anode Pt loading and flow channel design can cause an order of magnitude difference in CO tolerance under identical experimental conditions of temperature and current density.     

The neural networks based modeling of a polybenzimidazole-based polymer electrolyte membrane fuel cell: Effect of temperature

Neural network models represent an important tool of Artificial Intelligence for fuel cell researchers in order to help them to elucidate the processes within the cells, by allowing optimization of materials, cells, stacks, and systems and support control systems. In this work three types of neural networks, that have as common characteristic the supervised learning control (Multilayer Perceptron, Generalized Feedforward Network and Jordan and Elman Network), have been designed to model the performance of a polybenzimidazole-polymer electrolyte membrane fuel cells operating upon a temperature range of 100-175 °C. The influence of temperature of two periods was studied: the temperature in the conditioning period and temperature when the fuel cell was operating. Three inputs variables: the conditioning temperature, the operating temperature and current density were taken into account in order to evaluate their influence upon the potential, the cathode resistance and the ohmic resistance. The Multilayer Perceptron model provides good predictions for different values of operating temperatures and potential and, hence, it is the best choice among the study models, recommended to investigate the influence of process variables of PEMFCs.     

Comparison of phase-change-heat-pump cooling and liquid cooling for PEM fuel cells for MW-level aviation propulsion

Proton exchange membrane fuel cells (PEMFCs) are seen a key player in the sustainable and clean aviation transition. They can supply the main mega-watt (MW) level electric power aboard with many advantages. To notably increase their system specific power, a new phase-change-heat-pump (PCHP) cooling strategy is proposed and compared with the conventional liquid cooling through a model-based study. The comparison is carried out in terms of the induced drag power on a PEMFC-jet hybrid engine layout. The results reveal a drag reduction of 1.528 MW under the PCHP cooling, which accounts for about 16% of the aircraft's net cruise power. This saving is mainly from the minimized capacity of the heat exchanger between the PEMFCs and ambient. Besides, the ramjet effect also contributes significantly in the drag reduction. Last but not least, the optimal operating current density of the PEMFCs under PCHP cooling is brought up by about 26.5%.