直接甲醇燃料电池阴极水的传输特性

利用COMSOL Multiphysics软件对直接甲醇燃料电池(DMFC)阴极模型进行计算,获得压力、速度、水、氧气和液态饱和度分布情况,研究扩散层在不同物理参数(如厚度、孔隙率、孔径大小和亲憎水性)下电池阴极水和氧气的传输情况,进一步建立扩散层孔隙率梯度的数学模型,研究扩散层孔隙率梯度以及支撑层参数对直接甲醇燃料电池性能和物质传输的影响。结果表明,扩散层具有大孔隙率、薄扩散层时均有利于氧气传质,可以使电池性能提高;扩散层孔隙率梯度的存在可以减轻氧气传输阻力,提高电池性能。     

直接甲醇燃料电池阴极水的传输特性

利用COMSOL Multiphysics软件对直接甲醇燃料电池（DMFC）阴极模型进行计算，获得压力、速度、水、氧气和液态饱和度分布情况，研究扩散层在不同物理参数（如厚度、孔隙率、孔径大小和亲憎水性）下电池阴极水和氧气的传输情况，进一步建立扩散层孔隙率梯度的数学模型，研究扩散层孔隙率梯度以及支撑层参数对直接甲醇燃料电池性能和物质传输的影响。结果表明，扩散层具有大孔隙率、薄扩散层时均有利于氧气传质，可以使电池性能提高；扩散层孔隙率梯度的存在可以减轻氧气传输阻力，提高电池性能。     

SOFC中低浓度干甲烷在Ni/YSZ阳极上的反应

固体氧化物燃料电池(SOFC)趋向于直接使用甲烷天然气为燃料,确定甲烷在固体氧化物燃料电池阳极发生的化学与电化学反应非常重要.以Ni/YSZ为阳极、YSZ板做电解质、LSM为阴极,用涂浆法制作电解质支撑的电池,研究低浓度干甲烷在固体氧化物燃料电池中的反应.改变甲烷浓度、电池工作温度、电解质厚度,用在线色谱测量不同电流密度下,阳极出口气体产生速率.根据阳极出口气体产生速率变化,分析干甲烷在阳极的反应变化.通过氧消耗计算和转移电子数的分析,说明甲烷在电池阳极发生不同类型的反应.电流密度小时,甲烷发生部分氧化反应.电流密度大时,发生氢氧化和CO氧化,部分甲烷发生总反应为完全氧化的反应.部分甲烷发生完全氧化反应的同时,部分甲烷仍发生部分氧化反应,但其反应速率随电流密度增加逐渐降低.甲烷浓度和试验温度增加,甲烷开始发生完全氧化的电流密度增加.     

燃料电池与碳纤维之应用

介绍了以氢气为主要反应物的燃料电池作为替代性能源无污染和高效率的特点,燃料电池的应用领域、电池种类、工作原理和组成元件,以及逢甲大学研发之燃料电池气体扩散层技术。测试结果表明:当Load0.5V时,该自制的新型气体扩散层电流密度可达1026.4～1149.6mA/cm,而商用气体扩散层电流密度为941.6mA/cm;自制气体扩散层功率密度可达600mW/cm,而商用气体扩散层功率密度为511.2mW/cm,均高过商用气体扩散层。     

直接甲醇燃料电池研究现状

直接甲醇燃料电池主要由阳极扩散层、阴极扩散层、质子交换膜等组成,通过化学反应来传递能量,催化剂和质子交换膜对直接甲醇燃料电池性能影响很大,一旦解决技术难点,未来,直接甲醇燃料电池作为新兴绿色能源,将为我国经济发展提供重要的能源支持。     

球形团聚物模型在质子交换膜燃料电池过程模拟中的应用

在建立直通道质子交换膜燃料电池(PEMFC)的二维全电池数学模型中,将球形团聚物模型应用至两极的催化剂层。通过调节团聚物中质子传导介质的比例和催化层孔隙率,预测了基准供气状态下单电池的极化曲线,与文献报道的实验数据吻合良好。研究了电池运行过程中,膜电极内各化学组分和电流密度的分布情况及流向,比较了不同供气压力、催化剂铂颗粒尺寸等参数对电池性能的影响。计算结果表明,在阴极及时排出反应产生的水,并在阳极对燃料气进行加湿是保证单电池正常运行的前提,提高阴极的氧化剂气体压力,可显著改善PEMFC单电池性能,特别是在受浓差极化影响较大的大电流密度区;在催化剂铂载量相同的情况下,减小铂颗粒的尺寸可以提高电池的性能。     

质子交换膜燃料电池仿真模型研究进展

质子交换膜燃料电池具有高效清洁等优势,是一种潜力巨大的绿色能源技术。数学模型作为一种合理可靠的工具,通过模拟电池内部的电化学传热传质过程,研究运行参数和结构参数对电池性能和寿命的影响,可以指导电池的优化设计。本文综述了近年来燃料电池催化层、气体扩散层和流道的研究模型,整理了各部件建模的影响因素和优化方法,以期对燃料电池建模以及电池各部件的优化设计起到参考作用。文中指出,考虑到现在仿真存在的局限性,未来主要研究方向为燃料电池系统研究与机理模型的结合、催化层微观结构的建模、非贵金属催化剂建模、气体扩散层衰减模型研究、大面积流道模型、三维模型温度分布研究以及全尺寸质子交换膜燃料电池模型的开发。     

一种新型流道对燃料电池气体扩散层除水性能的模拟研究

燃料电池冷启动前,需要通过气体吹扫去除内部多余水分,停车后的吹扫对于燃料电池在低温下能否成功启动有着至关重要的影响。为了更有效地去除电池内部水分,提出一种有利于去除气体扩散层内部水分的新型波形流道,通过多物理场仿真软件(COMSOL Multiphysics)研究不同角度的波形流道对气体扩散层水分去除的影响以及水分去除的机理。计算结果表明:与传统的直形流道相比,这种新型波形流道能够增大气体扩散层上方的气体流速,有利于去除气体扩散层内部的水分,揭示了吹扫对气体扩散层水分去除的3个特征阶段:高饱和度区、恒速区以及快速下降区。     

燃料电池的研究现状及进展

按照阳极反应物燃料和反应机理不同,将燃料电池分为碳型燃料电池、氢型燃料电池、氮型燃料电池及有机物型燃料电池等几类,并结合近几年燃料电池方面的研究成果,分别介绍了这几种不同燃料电池的燃料种类、催化剂材料、极板设计及性能参数等方面的研究现状及进展,最后对燃料电池的未来进行了展望,指出以氢气为燃料的氢型燃料电池可形成高功率输出,且产物为水,绿色环保,而以酶或微生物为催化剂的有机物型燃料电池不仅可产生电能,同时可降解废水中有机物,改善水质。     

质子交换膜燃料电池水传递模型

提出了用于研究质子交换膜燃料电池膜中水分布、水传递量分布、电流密度分布等的二维数学模型;系统地考察了电池温度、阴阳极压力差、增湿程度、质子膜厚度等条件对水的传递和膜中水分布的影响.计算结果表明:①阳极增湿能够提高气体进口段膜阳极侧水的含量;②使用越薄的质子膜,越能提高膜中水的含量;③阳极增湿程度越大,由阳极向阴极迁移的水量越多.     

Anode Current Collecting Efficiency of Tubular Anode‐supported Solid Oxide Fuel Cells

Anode current collection points (ACCPs) were fabricated on the outside surface of a tubular anode‐supported solid oxide fuel cell (SOFC). The ACCPs were distributed axially along the SOFC tube with the distance between every adjacent two ACCPs the same. The effect of collecting current with different number of ACCPs on the performance of the SOFC was studied. It was found that with the same effective area, using more ACCPs to collect the current leads to better performance, while with a SOFC with a determined total surface area, there is an optimum number of ACCPs to be made and used considering the area occupied by the ACCPs themselves.     

Mathematical Modelling of Proton‐Conducting Solid Oxide Fuel Cells and Comparison with Oxygen‐Ion‐Conducting Counterpart

Proton‐conducting solid oxide fuel cells (H‐SOFC), using a proton‐conducting electrolyte, potentially have higher maximum energy efficiency than conventional oxygen‐ion‐conducting solid oxide fuel cells (O‐SOFC). It is important to theoretically study the current–voltage (J–V) characteristics in detail in order to facilitate advanced development of H‐SOFC. In this investigation, a parametric modelling analysis was conducted. An electrochemical H‐SOFC model was developed and it was validated as the simulation results agreed well with experimental data published in the literature. Subsequently, the analytical comparison between H‐SOFC and O‐SOFC was made to evaluate how the use of different electrolytes could affect the SOFC performance. In addition to different ohmic overpotentials at the electrolyte, the concentration overpotentials of an H‐SOFC were prominently different from those of an O‐SOFC. H‐SOFC had very low anode concentration overpotential but suffered seriously from high cathode concentration overpotential. The differences found indicated that H‐SOFC possessed fuel cell characteristics different from conventional O‐SOFC. Particular H‐SOFC electrochemical modelling and parametric microstructural analysis are essential for the enhancement of H‐SOFC performance. Further analysis of this investigation showed that the H‐SOFC performance could be enhanced by increasing the gas transport in the cathode with high porosity, large pore size and low tortuosity.     

氧化锆基固体电解质研究

电解质是固体氧化物燃料电池（SOFC）的核心部件,其性能的优良直接决定燃料电池的应用前景。氧化锆基陶瓷具有较高的离子电导率、良好的结构和化学稳定性,是理想的固体电解质材料。本文综合介绍了各种掺杂元素对氧化锆基固体电解质性能的影响,电解质薄膜制备方法和研究现状。并对氧化锆基固体电解质的研究方向进行了展望。     

Development of an In Situ Surface Deformation and Temperature Measurement Technique for a Solid Oxide Fuel Cell Button Cell

A novel experimental technique is developed to measure the in situ surface deformation and temperature of a solid oxide fuel cell (SOFC) anode surface along with the cell electrochemical performance. The experimental setup consists of a NexTech Probostat^™ SOFC button cell test apparatus integrated with a Sagnac interferometric optical method and an infrared sensor for in situ surface deformation and temperature measurements, respectively. The button cell is fed with hydrogen or simulated coal syngas under SOFC operating conditions. The surface deformation is measured over time to estimate the anode structural degradation. The cell surface transient temperature is also monitored with different applied current densities under hydrogen and simulated coal syngas. The experimental results are useful to validate and develop SOFC structural durability and electrochemical models.     

Direct Operation of IP‐Solid Oxide Fuel Cell with Hydrogen and Methane Fuel Mixtures under Current Load Cycle Operating Condition

The effects of methane concentration and current load cycle on the performance and durability of integrated planar solid oxide fuel cell (IP‐SOFC) obtained from Rolls Royce Fuel Cell Systems Ltd (RRFCS) has been investigated. The IP‐SOFC was operated with hydrogen–methane fuel mixture with up to 20% methane concentration at 900 °C for short term operation of the cells with high methane concentration increased the voltage of the IP‐SOFC due to increase in Gibbs free energy. However, it degraded the performance of the IP‐SOFC in long term operation due to carbon deposition on the anode surface. The current load cycle tests were carried out with 95% H₂–5% CH₄ and 80% H₂–20% CH₄ fuel mixtures at 900 °C with a constant current of 1 A. At low methane concentration, the decrease in the IP‐SOFC voltage was observed after operating nine current load cycles (384 h). At higher methane concentration, the voltage of IP‐SOFC decreased by almost 30% just after one current load cycle (48 h) due to faster carbon deposition. So future work is therefore required to identify viable alternative materials and optimum operating conditions.     

固体氧化物燃料电池发电系统的模拟与优化

固体氧化物燃料电池是21世纪最有希望作为分布式电源和大型电站的清洁高效的发电技术之一。针对1MW固体氧化物燃料电池发电系统,建立了描述SOFC电池堆电化学过程和特性的模型,并在此基础上建立了基于Aspen Plus软件平台的SOFC发电系统模型,对其系统参数进行了灵敏度分析和优化。     

Dynamic modelling and control of planar anode-supported solid oxide fuel cell

Most solid oxide fuel cell (SOFC) modelling efforts emphasize steady-state cell operation. However, understanding the dynamic behaviour is essential to predict the performance and limitations of SOFC power systems. This article presents the development of a SOFC dynamic model and a feedback control scheme that can maintain output voltage despite load changes. Dynamic responses are determined as the solutions of coupled partial differential equations derived from conservation laws of charges, mass, momentum and energy. To obtain the performance curve, the dynamic model is subjected to varying load current for different fuel specifications. From such a model, the voltage responses to step changes in the fuel concentration and load current are determined. Low-order dynamic models that are sufficient for feedback control design are derived from the step responses. The development of the partial differential equation model is outlined and the limitations of the control system are discussed.     

Investigation of solid oxide fuel cell short stacks for mobile applications by electrochemical impedance spectroscopy

Solid oxide fuel cells (SOFC) for mobile applications are developed and investigated at the German Aerospace Center (DLR) in Stuttgart. Therefore a light-weight stack design was developed in cooperation with the automotive industry (BMW/Munich, Elring-Klinger/Dettingen, ThyssenKrupp/Essen) and the Research Center Jülich (FZJ). This concept is based on the application of stamped metal sheet bipolar plates, into which the SOFC cells are integrated by brazing technology. For the development and the investigation of the SOFC cells and short stacks, the electrochemical impedance spectroscopy (EIS) is an important and useful characterization method. The paper concentrates on the investigation and on the electrochemical testing of the SOFC short stacks with sintered anode-supported cells (ASC). The short stacks were electrochemically characterized mainly by electrochemical impedance spectroscopy, by current-voltage measurements and by long-term measurements. The cells and stacks were operated at different temperatures, varying fuel gas compositions, different fuel gas flow rates and at different electrical current loads. The influence of these operating conditions on the electrochemical performance of the short stacks is outlined. The nature of losses, e.g. ohmic and the polarization resistances of the electrodes were examined and determined by fitting of the impedance spectra to an equivalent circuit.     

固体氧化物燃料电池阳极材料的研究进展

固体氧化物燃料电池（solid oxide fuel cells,SOFC）有着能量转换效率高,燃料适应性强和环境友好等优点,因此受到了人们的普遍关注,但是固体氧化物燃料电池的商业化应用还取决于其关键材料的进一步发展。介绍了SOFC对阳极材料的基本要求,重点评述了各种阳极材料的优缺点及其研究进展（包括金属、金属陶瓷、混合导体氧化物等）,并对改进阳极材料性能的各种措施进行了归纳总结。