Umicore Ag & Co Kg

Peter Seipel

Ralf Zuber

Sandra Wittpahl

Klaus Schaack

Holger Dziallas

Pia Braun

Lutz Rohland

Knut Fehl

Claus-Rupert Hohenthanner

Werner Roth

Günther Vulpius

Bernd Dillmann

Alexander Schade

Sven Bornbaum

Andreas Schmidt

Franz Greinemann

Bernhardt Barth

Heike Kuehnhold

The present invention relates to a novel method for producing metallic semifinished products by extrusion, to the thus obtainable semifinished products and to contact pieces that can be produced therefrom.

Method for producing a semifinished product for electrical contacts and contact piece

The invention relates to a membrane-electrode assembly (MEA) for electrochemical devices, in particular for membrane fuel cells. The membrane-electrode assembly has a semi-coextensive design and comprises an ion-conducting membrane, two catalyst layers and gas diffusion layers of differing sizes on the front side and rear side. The first gas diffusion layer has smaller planar dimensions than the ion-conducting membrane, while the second gas diffusion layer has essentially the same planar dimensions as the ion-conducting membrane. As a result, the ion-conducting membrane has a surface which is not supported by a gas diffusion layer on the front side. The membrane-electrode assembly has, owing to the particular construction, a stable structure which can be handled readily and displays advantages in the sealing of the reactive gases from one another and also in terms of the electrical properties. In particular, the hydrogen penetration current is significantly reduced. New processes for producing the MEA of the invention are described, in particular the method of heat pulse welding. The membrane-electrode assembly is used in PEM fuel cells, direct methanol fuel cells, electrolysers and other electrochemical devices.

Membrane electrode assembly for use in electrochemical devices

The invention relates to the field of electrochemical cells and fuel cells, more specifically to polymer-electrolyte-membrane fuel cells (PEMFC) and direct methanol fuel cells (DMFC). A multi-layer membrane-electrode-assembly (ML-MEA) comprising two electrically conductive bipolar plates and a membrane-electrode-assembly (MEA) bonded together by means of an electrically insulating adhesive material is disclosed. The adhesive material, preferably a polyurethane-based system, is in direct contact with the protective film layers attached to front side and the back side of the MEA, thus contamination of the ionomer membrane and/or the electrode layers with adhesive components is avoided. Multi-layer MEAs with improved long term stability and life time are obtained. The products are used for the manufacture of low temperature PEMFC and DMFC stacks.

Multi-layer membrane-electrode-assembly (ML-MEA) and method for its manufacture

The invention relates to membrane-electrode assemblies for the electrolysis of water (electrolysis MEAs), which contain an ion-conducting membrane having a front and rear side; a first catalyst layer on the front side; a first gas diffusion layer on the front side; a second catalyst layer on the rear side, and a second gas diffusion layer on the rear side. The first gas diffusion layer has smaller planar dimensions than the ion-conducting membrane, whereas the second gas diffusion layer has essentially the same planar dimensions as the ion-conducting membrane ('semi-coextensive design'). The MEAs also comprise an unsupported free membrane surface that yields improved adhesion properties of the sealing material. The invention also relates to a method for producing the MEA products. Pressure-resistant, gastight and cost-effective membrane-electrode assemblies are obtained, that are used in PEM water electrolyzers, regenerative fuel cells or in other electrochemical devices.

Membrane electrode unit for the electrolysis of water

The present invention provides a continuous process for producing catalyst-coated polymeric electrolyte membranes and membrane electrode assemblies for fuel cells. The process of the invention uses an ionomer membrane having a polymeric backing film on the back side. After the first coating step, the membrane is dried, during which the residual solvent may be almost completely removed. After this, the polymeric backing film is removed and the back side of the membrane is coated in a second step. The front and back sides of the membrane can be coated by various methods, such as screen printing or stencil printing. Two gas distribution layers are applied to the two sides of the catalyst-coated membrane to produce a 5-layer membrane electrode assembly. The membrane electrode assemblies are used in polymeric electrolyte membrane fuel cells and in direct methanol fuel cells.

Process for producing catalyst-coated membranes and membrane-electrode assemblies for fuel cells

Growing community of inventors

Alzenau, Germany

Peter Seipel