Fraunhofer-gesellschaft Zur Foerderung Der Angewandten Forschung E.v.

Technische Universitát Dresden

Technische Universitaet Dresden

Teja Roch

Eckhard Beyer

Andres Fabian Lasagni

Slavcho Topalski

Axel Zwick

Thomas Stucky

Eckhard Bever

Giorgio Maurizio

Dimitri Benke

Andrés Fabián Lasagni

A method for producing bipolar plates for fuel cells, one metal strip or two metal strips is/are guided through a second or third device. The second device is designed to carry out fine cleaning and/or nitriding of the metal strip, and the third device carries out surface coating on one side of a surface with a metal layer that improves adhesion. Applying a carbon layer in a fourth device. The metal strips are then shaped, during which process channels are formed. The shaped metal strips are moved and positioned such that surface regions come into contact with one another. Joining is performed with a laser beam, which is directed into a gap between the shaped metal strips moved towards one another. The individual steps in the devices, like shaping and joining, are carried out in a continuous process.

Method for producing bipolar plates for fuel cells

The bipolar plate of the invention for electrochemical cells, especially for proton-exchange membrane (PEM) fuel cells, is made with a metallic substrate and on the surface is made with an electrical contact resistance-reducing, carbon-based layer, a layer system or a boundary layer which is made of a near-surface, primarily sp2-bonded, carbon-based layer having a carbon fraction ranging from 50% to 100%, this layer being applied on a metallic substrate surface that is modified relative to the starting material. There may also be a surface region of the substrate in the form of an edge layer made with nitride and/or carbon by nitriding and/or carburizing. On the surface which is in touching contact with a gas-permeable element within the electrochemical cell, the metallic substrate may have a structuring made with elevations and/or depressions in the respective surface.

Bipolar plate for fuel cells, and production method

The invention relates to a method for forming a structuring at surfaces of components using a laser beam. In the invention, a laser beam is directed onto a diffractive optical element. The diffractive optical element is configured such that the laser beam is split into at least two part beams and the part beams are directed at an angle &#x3b1; with respect to the optical axis of the laser beam onto at least one further optical element which is transparent for the laser radiation. The further optical element(s) has/have a first surface and a second surface which is inclined at an angle to the optical axis of the laser beam at which the beam direction of the part beams is changed by optical refraction. A focusing optical lens is arranged in the optical path of the part beams between the further optical element(s) and a component surface to be processed, and the part beams are focused such that they are incident onto the surface of the component at a common position at an angle of incidence &#x3b2; with respect to the optical axis of the laser beam. The distance dbetween the optical elements is changed to change the interference period.

Method and arrangement for forming a structuring on surfaces of components by means of a laser beam

The invention relates to a device (and a corresponding method) for the interference structuring of a planar sample, comprising a laser, a focusing element, which is arranged in the beam path of the laser and by means of which the laser radiation can be focused in a first spatial direction, a first prism, in particular a biprism, which is arranged in the beam path of the laser and by means of which the laser radiation can be directed at a sample volume in a second spatial direction preferably perpendicular to the first spatial direction by means of two beams, in such a way that the two beams interfere within the sample volume in an interference area, the sample volume, in which the planar sample is or can be placed in the interference area, and a moving unit, by means of which the beam(s) of the laser radiation can be moved in the first, the second, or the first and second spatial directions and/or by means of which a/the sample can be moved in the sample volume in the first, the second, or the first and second spatial directions.

Device, arrangement, and method for the interference structuring of planar samples

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Dresden, Germany

Teja Roch