Modeling and Additive Manufacturing of Porous Electrodes for Novel High Temperature PEM Fuel Cells

提出的研究项目旨在增强有关新型燃料电池建模和制造的知识基础。因此，管状高温聚合物电解质膜（HT PEM）燃料电池将被开发、建模、制造和表征。管状高温PEM燃料电池有潜力将平面高温PEM燃料电池的优点结合起来，例如使用重整气体作为燃料，以及从SOFC技术中已知的管状设计（例如更高的功率密度和更高的效率）。在拟议的研究项目范围内，将设计这种新型燃料电池，并开发合适的模拟模型。模拟模型的核心要素将是分析燃料电池电极的孔隙特性及其对燃料电池性能的影响。在此基础上，对孔隙特性的要求将被定义并用于开发管状燃料电池电极的制造路线。由于电极必须具有多孔性（以允许质量传输）、机械稳定性（以支持其他功能层，如膜和催化涂层）和导电性，因此选择性激光熔化（SLM）等新型增材制造技术可能是满足所研究管状电极制造限制的可行方法。SLM是基于使用激光束逐层熔化细颗粒金属粉末。拟议研究项目的第二个目标是确定SLM技术作为多孔管状燃料电池电极的制造路线。因此，将研究SLM工艺参数(激光功率（PL）、扫描速度（vs）、孵化距离（hs）、层厚（s)、激光束直径(d)）以及粉末形貌（粒度分布）对孔隙度特征（总体孔隙度、开/闭孔隙度、孔隙大小和分布、渗透率）的影响，并将其用于建立经验模型。slm制造的燃料电池电极将被表征并用于优化和验证所开发的仿真模型。此外，利用适当的测试方法，如3D计算机断层扫描，将允许开发增强的模拟模型，其中孔隙度特征在微观水平上建模，而不是宏观的均匀方法。通过这种方法，可以在模拟中考虑孔隙度的性质，从而更准确地预测燃料电池的性能特性。

The proposed research project aims to enhance the knowledge base regarding modeling and manufacturing of novel fuel cells. Thereby tubular high-temperature polymer electrolyte membrane (HT PEM) fuel cells will be developed, modeled, manufactured, and characterized. Tubular HT PEM fuel cells have the potential to combine advantages of planar HT PEM fuel cells such as the usage of reformat gas as fuel with the ones of tubular designs which are known from SOFC techniques (e.g. higher power density and improved efficiency). Within the scope of the proposed research project such novel fuel cells are going to be designed and suitable simulation models will be developed. Core element of the simulation model will be the analysis of porosity characteristics of the fuel cell electrodes and how this affects the fuel cell performance. Based on the results requirements on porosity characteristics will be defined and used to develop a manufacturing route for the tubular fuel cell electrodes. Since the electrodes have to be porous (to allow mass transport), mechanically stable (to support other functional layers such as membrane and catalytic coating) and electrically conductive, novel additive manufacturing technologies such as selective laser melting (SLM) may be a feasible approach to meet the manufacturing constraints of the studied tubular electrodes. SLM is based on a layer-by-layer melting of fine-grained metal powder using a laser beam. A second objective of the proposed research project is the qualification of the SLM technique as a manufacturing route for defined porous tubular fuel cell electrodes. Therefore, the influence of SLM process parameters (laser power (PL), scan speed (vs), hatching distance (hs), layer thickness (s), and laser beam diameter (d)) as well as powder morphology (grain size distribution) on porosity characteristics (overall porosity, open/closed porosity, pore size and distribution, permeability) will be studied and used to develop an empirical model. SLM-manufactured fuel cell electrodes will be characterized and used to optimize and validate the developed simulation models. In addition, the utilization of adequate test methods such as 3D computer tomography will allow the development of enhanced simulation models, in which porosity characteristics are modeled on a microscopic level instead of a macro homogenous approach. In this way the nature of the porosity can be considered in the simulation to predict the fuel cell performance characteristics more accurately.