质子交换膜燃料电池动态特性仿真

在质子交换膜燃料电池(proton exchange membrane fuel cells, PEMFC)经验模型的基础上,建立了一种PEMFC动态特性建模和仿真的方法,应用MATLAB的SIMULINK仿真工具建立了PEMFC的动态仿真模型,仿真研究了电池堆的运行参数等对电池输出性能的影响.该方法可以应用于燃料电池的动态特性仿真分析、优化设计和燃料电池系统的自动控制.     

质子交换膜燃料电池流场板研究进展

质子交换膜燃料电池具有比能量高、清洁高效等优点, 流道作为燃料电池的核心结构之一, 其结构尺寸对气体传输、液态水排出都有着重要影响, 选择合适尺寸参数对实际运行具有重要意义。以50 mm×50 mm单蛇形流道电池为研究对象, 采用数值模拟的方法, 建立质子交换膜燃料电池三维两相等温模型, 分析流道深度、流道宽度、流道脊宽等参数对电池电流密度、气体传质特性、电池净输出功率、排水性能的影响。结果表明: 随着流道深度、流道宽度的减小, 参与反应的氧气浓度提高, 电流密度也随之提高, 电池净输出功率逐渐增大, 催化层排水性能逐渐增强, 因此电池性能逐渐提高; 随着流道脊宽的减小, 参与反应的氧气浓度逐渐提高, 电流密度随之增大, 但电池净输出功率增加幅度较小, 氧气浓度增加也较缓慢。

     

交指状流场质子交换膜燃料电池的数值分析

为研究流场结构设计对电池内的流动、组分传递和电池性能等的影响,建立了一个稳态的三维非等温质子交换膜燃料电池数学模型,应用此模型对一个交指状流场设计的电池单体（电极面积为64 cm ×65 cm）进行了数值研究.数值计算得到了电池的温度、组分质量浓度和局部电流密度等的空间分布,分析了不同电池反应物湿度等对电池特性的影响.结果表明,受传质的影响,沟道下方阴极催化层的温度大于相应沟脊下方的区域;与饱和气流进气的基本工况相比,降低阴极的进气湿度能提高电池的性能,而降低阳极的进气湿度则会导致电池性能的下降.     

基于MATLAB的质子交换膜燃料电池仿真实验系统

利用燃料电池的经验方程建立了质子交换膜燃料电池（PEMFC）的一维稳态模型,进行了仿真和结果分析,仿真结果与实验数据吻合较好.利用VB(Visual Basic)编写人机交互界面作为前台用户程序,以MATLAB的SIMULINK在后台运行,发展了一种基于MATLAB和VB软件包的质子交换膜燃料电池特性参数仿真实验软件,并对PEMFC的工作温度、反应气压力等参数对其性能的影响进行了仿真分析,有助于进行燃料电池特性参数仿真实验以及对燃料电池的分析、设计和优化.     

基于MATLAB的质子交换膜燃料电池仿真实验系统

利用燃料电池的经验方程建立了质子交换膜燃料电池（PEMFC）的一维稳态模型，进行了仿真和结果分析，仿真结果与实验数据吻合较好．利用VB（Visual Basic）编写人机交互界面作为前台用户程序，以MATLAB的SIMULINK在后台运行，发展了一种基于MATLAB和VB软件包的质子交换膜燃料电池特性参数仿真实验软件，并对PEMFC的工作温度、反应气压力等参数对其性能的影响进行了仿真分析，有助于进行燃料电池特性参数仿真实验以及对燃料电池的分析、设计和优化．     

不同流道结构质子交换膜燃料电池内传递现象的三维模拟

应用计算流体力学方法，建立了用于模拟质子交换膜燃料电池（PEMFC）传递特性和电化学性能的稳态、等温的三维数学模型。计算了传统流道和交叉梳状流道燃料电池的流场、电流密度和组分浓度等的多维分布。与传统流道的燃料电池相比，交叉梳状流道所产生的电极内强烈的强制对流机理提高了反应物和产物的传输速率，从而改善了电池的极限电流和极化性能等。利用模型估算的极化特性和文献实验结果吻合较好。     

质子交换膜燃料电池的湿度特性和水的迁移途径

质子交换膜燃料电池的工作性能与湿度密切相关。本文研究了影响质子交换膜燃料电池水平衡的各种因素:电流密度上升,阴极生成的水量也逐渐增多;随着电地温度的提高,维持电池水平衡的电流密度必须提高;为减小欧姆损失,阳极气流需要增湿。本文分析了质子交换膜燃料电池水迁移的原理。为了利用反应生成的水,要采用水管理方法:水管理不足以获得足够含水率时,应采用加湿技术。本文比较了内外加湿法的优劣,借助数学建模的方法模拟了电池内部的工作过程,预测内部湿化系统可以免除气体交叉现象的出现,可以克服电池性能受到影响的弊病。     

质子交换膜燃料电池阴极有序催化层数学模拟

建立了质子交换膜燃料电池阴极有序催化层的二维数学模型以分析影响性能的主要因素并优化结构参数.模型方程涉及质子、电子传导,气体扩散和电化学反应等过程,并以有限元法求解.计算结果表明,阴极有序催化层通过降低传质阻力而显著提高了电化学性能;影响传递性能的主要因素是O2通过电解质膜的扩散,电子和质子传导以及O2的气相扩散作用不大;降低碳载体和气孔直径、增加催化层厚度主要通过增加催化剂载量改善催化层性能,而减小电解质膜厚度可以促进O2扩散而提高催化层性能.     

质子交换膜燃料电池热回收的实验研究

对质子交换膜燃料电池的热回收进行了实验研究.实验数据表明:热回收后燃料电池的整体效率提高幅度最小为7.54%,最大为23.8%,因此热回收对于节能及加快燃料电池这种清洁能源的推广应用有着重大意义.     

Neural network modeling and control of proton exchange membrane fuel cell

A neural network model and fuzzy neural network controller was designed to control the inner impedance of a proton exchange membrane fuel cell (PEMFC) stack. A radial basis function (RBF) neural network model was trained by the input-output data of impedance. A fuzzy neural network controller was designed to control the impedance response. The RBF neural network model was used to test the fuzzy neural network controller. The results show that the RBF model output can imitate actual output well, the maximal error is not beyond 20 m-, the training time is about 1 s by using 20 neurons, and the mean squared errors is 141.9 m-2. The impedance of the PEMFC stack is controlled within the optimum range when the load changes, and the adjustive time is about 3 min.     

The use of phase-change cooling strategy in proton exchange membrane fuel cells: A numerical study

Science China Technological Sciences - Thermal management is considered a critical issue in proton exchange membrane fuel cells (PEMFCs), since it not only influences the cell performance but also...     

Graphite-polypyrrole coated 316L stainless steel as bipolar plates for proton exchange membrane fuel cells

316L stainless steel(SS 316L) is quite attractive as bipolar plates in proton exchange membrane fuel cells(PEMFC).In this study,graphite-polypyrrole was coated on SS 316L by the method of cyclic voltammetry.The surface morphology and chemical composition of the graphite-polypyrrole composite coating were investigated by scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy(XPS).A simulated working environment of PEMFC was applied for testing the corrosion properties of graphite-polypyrrole ...     

三维质子交换膜燃料电池的完整模型

通过聚集体模型描述催化层结构,建立了阴阳极包括蛇形流道、多孔扩散层、质子交换膜和催化层的完整质子交换膜燃料电池(PEMFC)三维流体力学模型,重点研究稳态条件下的基本工作参数分布和气体扩散层渗透率的影响.模型方程借助于计算流体力学软件-F luent求解.模拟的极化行为验证了模型的有效性,说明在燃料电池模型中充分考虑催化层的必要性.计算结果表明流体流速、压力、反应气体组成和局部电流密度等参数的空间分布明显,并且受气体扩散层渗透率影响明显,优化气体扩散层结构至关重要.     

Nafion/Silicon Oxide Composite Membrane for High Temperature Proton Exchange Membrane Fuel Cell

Nafion/Silicon oxide composite membranes were produced via in situ sol-gel reaction of tetraethylorthosilicate （TEOS） in Nafion membranes. The physicochemical properties of the membranes were studied by FT-IR,TG-DSC and tensile strength. The results show that the silicon oxide is compatible with the Nation membrane and the thermo stability of Nation/Silicon oxide composite membrane is higher than that of Nation membrane. Furthermore, the tensile strength of Nation/Silicon oxide composite membrane is similar to that of the Nation membrane. The proton conductivity of Nation/Silicon oxide composite membrane is higher than that of Nation membrane. When the Nation/Silicon oxide composite membrane was employed as an electrolyte in H2/O2 PEMFC, a higher current density value （1 000 mA/cm^2 at 0.38 V） than that of the Nafion1135 membrane （100 mA/cm^2 at 0.04 V） was obtained at 110 ℃.     

Experimental investigation of liquid water in flow field of proton exchange membrane fuel cell by combining X-ray with EIS technologies

The flow field is a pivotal part to manage the transport of water and gas in proton exchange membrane fuel cell. However, the reported water measurement methods (e.g., X-ray and electrochemical impedance spectroscopy (EIS)) cannot give a comprehensive understanding water distribution in the flow field, resulting in challenges in optimizing the channel design and enhancing fuel cell performance. Therefore, we propose a water measurement method combining the X-ray radiography with EIS to investigate the effect of different operating conditions on the growth law and distribution of liquid water in parallel and serpentine flow fields. The attenuation coefficient of liquid water to X-ray is calibrated with constant tube-current and tube-voltage of X-ray generator. Besides, the parallel flow field with hydrophobic treatment is studied. The results show that the water accumulation of the parallel flow field is far more than the serpentine flow field, and the water content of the middle region is higher than that of other regions in the parallel flow field. Furthermore, operating conditions (cathode inlet gas flow rate, inlet gas humidity, and back pressure) have little effect on the liquid water content of the middle region in the parallel flow field. The polarization curve, EIS result, and X-ray radiography show that the performance and water drainage capacity of the hydrophobic parallel flow field are better than the normal one.

     

Control-oriented dynamic fuzzy model and predictive control for proton exchange membrane fuel cell stack

Proton exchange membrane fuel cell （PEMFC） stack temperature and cathode stoichiometric oxygen are very important control parameters. The performance and lifespan of PEMFC stack are greatly dependent on the parameters. So, in order to improve the performance index, tight control of two parameters within a given range and reducing their fluctuation are indispensable, However, control-oriented models and control strategies are very weak junctures in the PEMFC development. A predictive control algorithm was presented based on their model established by input-output data and operating experiences. It adjusts the operating temperature to 80℃. At the same time, the optimized region of stoichiometric oxygen is kept between 1.8-2.2. Furthermore, the control algorithm adjusts the variants quickly to the destination value and makes the fluctuation of the variants the least. According to the test results, compared with traditional fuzzy and PID controllers, the designed controller shows much better performance.     

Identification and analysis based on genetic algorithm for proton exchange membrane fuel cell stack

The temperature of proton exchange membrane fuel cell stack and the stoichiometric oxygen in cathode have relationship with the performance and life span of fuel cells closely. The thermal coefficients were taken as important factors affecting the temperature distribution of fuel cells and components. According to the experimental analysis, when the stoichiometric oxygen in cathode is greater than or equal to 1.8, the stack voltage loss is the least. A novel genetic algorithm was developed to identify and optimize the variables in dynamic thermal model of proton exchange membrane fuel cell stack, making the outputs of temperature model approximate to the actual temperature, and ensuring that the maximal error is less than 1℃. At the same time, the optimum region of stoichiometric oxygen is obtained, which is in the range of 1.8 -2.2 and accords with the experimental analysis results. The simulation and experimental results show the effectiveness of the proposed algorithm.     

复杂流道质子交换膜燃料电池的三维数值分析

针对模拟复杂流道设计质子交换膜燃料电池（proton exchange membrane fuel cell ，PEMFC）的传热传质过程和电池电化学性能，提出一个稳态的、非等温的三维数学模型.应用模型对一个电极面积为3.12 cm×4 cm，20条通路的“蛇形”流道结构PEMFC进行数值计算，得到电池的流场、局部电流密度和组分浓度等的多维分布.并分析了不同渗透率对电池特性所产生的影响.结果表明,渗透率越高，压力降越小，有利于提高电池的性能.