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Series Production of Membrane Electrode Assembly by means of a Double Belt Press

29 Jun 2023
Fuel Cell Technology
Successful proton exchange membrane fuel cell (PEMFC) projects involve precise fabrication of the core module, the Membrane Electrode Assembly (MEA). Many works have been conducted to optimize thickness, porosity, as well as thermal and electrical properties of the MEA components. In general, the aim is to improve heat and electricity conduction, and to facilitate the adsorption and diffusion of fuel atoms through the thin catalyst layer (CL). Regarding contact structure between the Gas diffusion Layer (GDL) and the CL, microstructure is crucial for increasing the adsorption density of reactants and products as well as help water management. The optimization of the composite microstructure structures leads to higher cell performance. Composite reinforcements randomly distributed in the GDL, for instance nanotubes or carbon fiber, fulfill such requirements. However, the presence of such microstructures is very dependent on the manufacturing process. For instance, to control product thickness and stiffness, the reinforcements are frequently pressed with a hydrophobic thermoplastic, e.g., polytetrafluoroethylene (PTFE), above the glass transition temperature. A conventional high temperature press process, e.g., calender rolls, straighten or flatten the material, consequently reducing porosity drastically. Alternatively, this work shows the benefit of pressing the material at a constant pressure, by means of an isobaric double belt press. Isobaric double belt presses prevent flattening of the surface structure, thermally treating the MEA with high precision, and increasing the manufacture scalability compared to a conventional calender process. Moreover, it offers an opportunity to produce an entire cell stack, roll-to-roll, or roll-to-plate process. 
Tiago Soares, Development Manager - Held Technologie GmbH