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

• Applicants: Professor Dr.-Ing. Eberhard Abele; Professor Dr.-Ing. Manfred J. Hampe
• Subject Area: Production Automation and Assembly Technology ; Chemical and Thermal Process Engineering ; Metallurgical, Thermal and Thermomechanical Treatment of Materials
• Term: from 2015 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 280769153

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.

• DFG Programme: Research Grants