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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Manufacture and performance of the MEA of a 500W Proton exchange membrane fuel cell (PEMFC)

Tsai, Po-feng 09 March 2012 (has links)
This study has two purposes: First, the catalyst-coated membrane (CCM) method to produce high performance and high utilization of electrode, and the other is to enhance the fuel cell performance with the heterogeneous carbon fiber bunch framework of stack. First, to establish an ideal electrode structure, there has an intensive triple phase boundaries. We will describe how the procedure of reliable and practical electrode improved following the optimization of (1) the spray system, and (2) the catalyst dispersion. We will also focus (3) modification of the spray system, and (4) electrode performance analysis. In addition, investigate of the single cell performance in heterogeneous carbon fiber bunch framework. We will find that: (1) Increasing the catalyst loading and concentrated the catalyst activation reaction, can be improve the electrode performance and catalyst utilization. (2) Coating a thin conductive layer onto membrane electrode (ME), be a precise hot-pressue process in the Stack and MEA or GDL and ME, can be reduce the contact resistance. Specially, reduce the carbon fiber coverage fraction with electrode area, result the activation reaction decay and ohmic loss obviously. (3) Increasing the gas flow rate, can enhance the mass transfer performance, but increase the pressure of the reaction gas, can¡¦t significant effect on performance. Besides, when the stack is anode side up, seems favorable to the exclusion the generate water of cathode.
2

Inkjet printing processes as an innovative manufacturing method for the production of catalytically coated membranes (CCM) for fuel cells as well as electrolyzers

Willert, Andreas, Zeiner, Christian, Zubkova, Tatiana, Zichner, Ralf 27 May 2022 (has links)
Digitally controlled inkjet printing technology has attractive features for the production of catalyst coated membranes (CCM) for application either in electrolysers or in fuel cells. There are a number of unique features: pattern like coating for effective use of expensive materials like platinum or iridium, direct deposition onto membrane material, non-impact printing, easy change of pattern design, and ability to generate catalytic gradients. Employing inkjet printing technology enables the manufacturing of catalytic layers as well as other components. The challenges are to evaluate process-compatible inks as well as processing parameters. / Die digital gesteuerte Inkjetdrucktechnologie hat attraktive Eigenschaften für die Herstellung von katalysatorbeschichteten Membranen (CCM), die entweder in Elektrolyseuren oder in Brennstoffzellen eingesetzt werden. Es gibt eine Reihe einzigartiger Merkmale: mustergenaue Beschichtung für den effektiven Einsatz teurer Materialien wie Platin oder Iridium, direkte Bedruckung des Membranmaterials, berührungsfreies Drucken, einfache Änderung des Druckdesigns und die Fähigkeit, katalytische Gradienten zu erzeugen. Der Einsatz der Inkjetdrucktechnologie ermöglicht die Herstellung von katalytischen Schichten und anderen Komponenten. Die Herausforderungen bestehen darin, prozesskompatible Tinten sowie Verarbeitungsparameter zu evaluieren.
3

Tiefdruckverfahren zur Herstellung von Katalysatorschichten für (PEM) Brennstoffzellen

Siegel, Frank 23 November 2015 (has links)
Diese Dissertation befasst sich mit der industrienahen Herstellung von Katalysatorschichten für Polymer-Elektrolyt-Membran-Brennstoffzellen mit Hilfe des Tiefdrucks als Fertigungsverfahren. Um die Anforderungen an die Katalysatorschicht hinsichtlich der Schichtdicke zu erreichen, wird ein Linienraster für den Tiefdruck entwickelt. Das patentierte und verifizierte Designkonzept des Linienrasters ermöglicht es, trotz Tinten mit geringem Feststoffgehalt hohe Trockenschichtdicken zu erzeugen. Aufgrund des verwendeten Tiefdruckrasters sind Optimierungsschritte an der Fertigungsanlage notwendig, um eine hohe Schichtqualität zu erreichen. Schließlich werden kontinuierlich und industrienah Katalysatorschichten gefertigt, die als Membran-Elektroden-Einheit in einer Polymer-Elektrolyt-Membran-Brennstoffzelle erfolgreich eingesetzt werden. / This work presents an industrial close manufacturing process of active electrodes for Polymer Electrolyte Fuel Cells utilizing an adapted gravure printing process. To meet the requirements of the electrodes regarding the layer thickness (weight) and quality a novel line screen with maximized dipping volume for gravure printing was developed and investigated. A design rule for this kind of screens was realized and verified by a successful manufacturing of electrodes with different dried layer thicknesses. Due to the rough structure and the high dipping volumes of these line screens an adaption and optimization of the machinery and the whole process was necessary to achieve high quality electrodes. Finally, it is shown that it is possible to manufacture continuiously in an industrial close roll-to-roll process platinum loaded electrodes, working successful as cathode in a Membran-Electrode-Assembly.

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