[go: up one dir, main page]

EP1627439A2 - Contact device and fuel cell stack or block comprising one such contact device - Google Patents

Contact device and fuel cell stack or block comprising one such contact device

Info

Publication number
EP1627439A2
EP1627439A2 EP04726996A EP04726996A EP1627439A2 EP 1627439 A2 EP1627439 A2 EP 1627439A2 EP 04726996 A EP04726996 A EP 04726996A EP 04726996 A EP04726996 A EP 04726996A EP 1627439 A2 EP1627439 A2 EP 1627439A2
Authority
EP
European Patent Office
Prior art keywords
contact device
fuel cell
surface layer
contact
hydrophobic surface
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP04726996A
Other languages
German (de)
French (fr)
Inventor
Albert Hammerschmidt
Herbert Hartnack
Arno Mattejat
Igor Mehltretter
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens AG
Original Assignee
Siemens AG
Siemens Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens AG, Siemens Corp filed Critical Siemens AG
Publication of EP1627439A2 publication Critical patent/EP1627439A2/en
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0204—Non-porous and characterised by the material
    • H01M8/0221—Organic resins; Organic polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0204—Non-porous and characterised by the material
    • H01M8/0206—Metals or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0204—Non-porous and characterised by the material
    • H01M8/0223—Composites
    • H01M8/0228—Composites in the form of layered or coated products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0247—Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the form
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/24—Grouping of fuel cells, e.g. stacking of fuel cells
    • H01M8/241—Grouping of fuel cells, e.g. stacking of fuel cells with solid or matrix-supported electrolytes
    • H01M8/242—Grouping of fuel cells, e.g. stacking of fuel cells with solid or matrix-supported electrolytes comprising framed electrodes or intermediary frame-like gaskets
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M2008/1095—Fuel cells with polymeric electrolytes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

Definitions

  • the invention relates to a contact device for electrical contacting of a fuel cell stack and a fuel cell stack or a fuel cell block with such a contact device.
  • Fuel cells are becoming increasingly important in future-oriented concepts for energy generation.
  • low-temperature fuel cells based on the polymer electrolyte membrane (PEM) technology are being discussed as environmentally friendly and efficient energy converters for portable, mobile and stationary applications and are already being used commercially for the first time. They convert hydrogen and oxygen into electrical direct current at temperatures just above freezing up to approx. 90 ° C, the only by-product being water.
  • PEM polymer electrolyte membrane
  • the resulting water is predominantly in liquid form and must be removed from the fuel cells in a suitable form. This is usually done via connection plates at the ends of the fuel cell stack. To do this, the water is fed lengthways through the fuel cell stack.
  • suitable components through which deionized water flows are used in the fuel cell stacks.
  • the supply and discharge of the cooling water passed through the stack is usually also via the connection plates at the ends of the stack. To do this, the deionized water is fed lengthways through the stack.
  • connection device In the vicinity of the connection plates at the ends of the fuel cell stack there is a contact device in an operating gas-free connection space, which makes electrical contact with the fuel cell stack and leads the current out of the fuel cell stack via connection lugs.
  • the contact device is e.g. from a contact plate that is in electrical contact with a pole or bipolar plate that closes off the fuel cell stack and, if necessary, holding elements, e.g. made of an elastomer, with which it is held and / or aligned on the fuel cell stack.
  • the contact device can include further components such as Include contact spring plates or contact foils. All of these components are intended to conduct the current as well as possible and are therefore usually made of an electrically highly conductive material, e.g. made of copper or a copper alloy.
  • the atmosphere must be dried continuously, at least regularly, as part of service measures on the fuel cell stacks. Drying can be carried out, for example, by flushing the room with dry gases such as nitrogen or by applying a vacuum.
  • dry gases such as nitrogen
  • these procedures are time consuming and costly. It is therefore an object of the present invention to provide a contact device which simplifies the discharge of water from the connection space.
  • a contact device according to claim 1.
  • a fuel cell stack or a fuel cell block with such a contact device is the subject of claims 15 and 16.
  • Advantageous embodiments of the invention are the subject of the dependent claims.
  • the invention is based on the consideration that the surface of the contact device has pores. These pores have hydrophilic properties, particularly on metallic surfaces. Water on the surface of the contact device is literally sucked into pores like a capillary.
  • the contact device has holding elements, in particular made of an elastomer, for holding and / or aligning the contact device on a fuel cell stack, the discharge of the water can thereby be simplified even further that these holding elements are also at least partially provided with the hydrophobic surface layer.
  • a good current conductivity of the contact device and at the same time a good discharge of the water from the connection space is possible in that the thickness of the hydrophobic surface layer in the area of electrical connection points, e.g. between the contact device and an adjacent pole or bipolar plate, is set to an optimum between a low electrical contact resistance and a high hydrophobicity.
  • the hydrophobic surface layer contains polytetrafluoroethylene (PTFE).
  • PTFE polytetrafluoroethylene
  • the surface layer advantageously consists of a PTFE metal or PTFE-carbon mixture in order to achieve a low electrical contact resistance.
  • the hydrophobic surface layer consists of a hydrophobizing material that is soluble in a solvent.
  • This material can be applied to the surface of the contact device in the dissolved state and very thin layers can thus be achieved.
  • the contact device can thus be given good current conductivity, which cannot be achieved, for example, with pure PTFE coatings.
  • the hydrophobic surface layer made of the solvent-soluble, hydrophobizing material is therefore particularly suitable for electrical connection points.
  • the detachable, hydrophobizing material preferably consists entirely or partially of an amorphous fluoropolymer, alternatively polisiloxane compounds or alkylsilanes are also suitable. These materials have a particularly good adhesion to metals.
  • Amorphous modifications of Teflon are particularly suitable among the amorphous fluoropolymers.
  • This material can be obtained in suitable solvents and diluted to an optimal concentration before use.
  • the solution can then be applied to the corrosion protection layer by a customary application method such as spraying, wiping, brushing, dipping, printing, the solvent evaporated and the remaining material, if appropriate, immobilized on the corrosion protection layer by a temperature step at elevated temperature. After the solvent has evaporated, a very thin Teflon film remains, which in particular covers the inner surfaces of the pores.
  • the contact device according to the invention is particularly advantageously suitable for tapping the current generated by a fuel cell stack.
  • FIG. 1 shows a cross section through a fuel cell stack with a contact device according to the invention
  • 2 shows a part of the contact device of Figure 1 in an enlarged view.
  • a fuel cell stack 1 shown in FIG. 1 consists of several membrane electrode units 3 and bipolar plates 5, which are alternately stacked one on top of the other, and is closed off by a bipolar plate 5a.
  • a membrane electrode unit 3 consists of an anode 7, a membrane 9 and a cathode 11.
  • the membrane electrode units 3 and the bipolar plates 5, 5a are mounted in seals 13.
  • humidified hydrogen flows into the anode gas spaces 23, which are each arranged between the anode 7 of a membrane electrode unit 3 and an adjacent bipolar plate 5.
  • oxygen moistened with water flows into the cathode gas spaces 25, which are each arranged between the cathode 11 of a membrane electrode unit 3 and an adjacent bipolar plate 5.
  • the cathode gas spaces 25 are flowed with with humidified oxygen.
  • the side of the bipolar plate 5a facing away from the cathode gas spaces 25 borders on a connection space 49 which is free of the operating gases hydrogen and oxygen.
  • cooling water flows from an axial channel 27 into the cavities 19 of the bipolar plates 5 and 5a during operation of the fuel cell stack 1.
  • the heat of reaction flowing into the cavities 19 through the bipolar plate 5 or 5a is absorbed by the cooling water, which flows further into another axial channel 31 and is removed from there from the fuel cell stack 1.
  • the current generated by the fuel cell stack 1 is tapped electrically with the aid of a bipolar plate 5a which closes the connection space 49 and closes the terminal Contacting contact device 4.
  • This comprises a contact plate 42, which is in electrical contact with the bipolar plate 5a via contact springs 43 and a contact foil 44.
  • the components 42, 43, 44 consist of copper or a copper alloy in their base material to ensure a particularly good conductivity.
  • the contact springs 43 serve to compensate for tolerances between the contact plate 42 and the fuel cell stack 1, the contact film 44 brings about a particularly low contact resistance between the bipolar plate 5a and the contact springs 43.
  • the contact plate 42, the contact springs 43 and the contact foil 44 are provided on their surface with a hydrophobic surface layer 45.
  • a particularly low contact resistance between the hydrophobic surface layer 45 and the base material of the contact plate 42, the contact springs 43 or the contact film 44 is achieved in that, in addition, a highly conductive contact layer 46 made of one or more precious metals between the base material and the hydrophobic surface layer 45, in particular made of gold and nickel.
  • the contact device 4 also has holding elements 47 made of an elastomer for holding and aligning the contact device 4 on the fuel cell stack 1, which also serve to seal the connection space 49 with respect to the axial channel 27 or 31.
  • the elastomer material also makes it possible to compensate for tolerances in the fuel cell stack 1.
  • the holding elements 47 are also partially provided with a hydrophobic surface layer 45.
  • the pores present on the surface of the contact device 4 or the contact plate 42, the contact springs 43, the contact film 44 and the holding elements 47 are closed by the hydrophobic surface layer 45. If water comes onto the surface of the contact device, dripping Chen Struktur, wherein the droplets have little adhesion to the surface and can be applied with a small gas flow from the connection space 49 and thus from the fuel cell stack 1.
  • the hydrophobic surface layer preferably consists of an amorphous modification of Teflon (for example an amorphous copolymer of 65-99 mol% perfluoro-2, 2-dimethyl-1,3-dioxol with a complementary amount of tetrafluoroethylene, under the product name Teflon®AF from DuPont Fluoroproducts available).
  • Teflon®AF amorphous copolymer of 65-99 mol% perfluoro-2, 2-dimethyl-1,3-dioxol with a complementary amount of tetrafluoroethylene
  • the thickness of the hydrophobic surface layer 45 is made of amorphous Teflon at these connection points 48 is set to an optimum between a low contact resistance and a high hydrophobicity. This is possible in particular in that the hydrophobic surface layer 45 has a thickness in the range from 0.1 nm to 10 nm, in particular 0.5 nm to 0.7 nm, at these electrical connection points 48.
  • a dilution of the amorphous Teflon with a solvent in a ratio of 1: 200 has proven to be suitable for this.
  • the thin layer that can be achieved on the contact foil 44 can be mechanically pushed aside by the contact springs 43, for example.
  • the Teflon then remains in the pores and brings about the desired hydrophobicity, while the contact points on the contact film 44 are free of Teflon and thus have only a low contact resistance.
  • the amorphous Teflon can be applied undiluted.
  • the thickness of the hydrophobic layer there is advantageously 0.01 ⁇ m to 100 ⁇ m, in particular 0.01 ⁇ m to 1 ⁇ m.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Composite Materials (AREA)
  • Fuel Cell (AREA)

Abstract

The invention relates to a contact device (4) which is arranged in a terminal compartment (49) of a fuel cell stack (1) and is used to electrically contact the fuel cell stack (1). According to the invention, the surface of said contact device is at least partially provided with a hydrophobic surface layer (45), facilitating the removal of water, e.g. condensation water, from the terminal compartment (49) and thus from the fuel cell stack (1).

Description

Kontaktvorrichtung sowie BrennstoffZellenstapel bzw. Brennstoffzellenblock mit einer derartigen KontaktvorrichtungContact device and fuel cell stack or fuel cell block with such a contact device

Die Erfindung betrifft eine Kontaktvorrichtung zur elektrischen Kontaktierung eines Brennstoffzellenstapels sowie einen Brennstoffzellenstapel bzw. einen Brennstoffzellenblock mit einer derartigen Kontaktvorrichtung.The invention relates to a contact device for electrical contacting of a fuel cell stack and a fuel cell stack or a fuel cell block with such a contact device.

Brennstoffzellen gewinnen immer mehr an Bedeutung in zukunftsweisenden Konzepten für die Energieerzeugung. Insbesondere Niedertemperatur-Brennstoffzellen auf Basis der Polymer- Elektrolytmembran (PEM) -Technologie werden als umweltfreundliche und effiziente Energiewandler für portable, mobile und stationäre Anwendungen diskutiert und finden bereits erste kommerzielle Verwendung. Sie setzen bei Temperaturen bei kurz über dem Gefrierpunkt bis ca. 90 °C Wasserstoff und Sauerstoff in elektrischen Gleichstrom um, als einziges Nebenprodukt entsteht dabei Wasser. Üblicherweise sind hierbei eine Mehrzahl von Brennstoffzellen in Form eines Brennstoffzellensta- pels in Reihe geschaltet.Fuel cells are becoming increasingly important in future-oriented concepts for energy generation. In particular, low-temperature fuel cells based on the polymer electrolyte membrane (PEM) technology are being discussed as environmentally friendly and efficient energy converters for portable, mobile and stationary applications and are already being used commercially for the first time. They convert hydrogen and oxygen into electrical direct current at temperatures just above freezing up to approx. 90 ° C, the only by-product being water. Usually, a plurality of fuel cells in the form of a fuel cell stack are connected in series.

Das entstehende Wasser fällt bei den Betriebstemperaturen ü- berwiegend in flüssiger Form an und muss in geeigneter Form aus den Brennstoffzellen entfernt werden. Dies erfolgt üblicherweise über Anschlussplatten an den Enden des Brennstoffzellenstapels. Dazu wird das Wasser längs durch den Brennstoffzellenstapel geleitet.At the operating temperatures, the resulting water is predominantly in liquid form and must be removed from the fuel cells in a suitable form. This is usually done via connection plates at the ends of the fuel cell stack. To do this, the water is fed lengthways through the fuel cell stack.

Um die bei der Stromerzeugung in den Brennstoffzellen entstehende Verlustwärme abzutransportieren, werden in den Brennstoffzellenstapeln geeignete, von deionisiertem Wasser durchströmte Bauelemente eingesetzt. Die Zu- und Abführung des durch den Stapel geleiteten Kühlwassers erfolgt üblicherweise ebenfalls über die Anschlussplatten an den Enden des Stapels. Dazu wird das deionisierte Wasser längs durch den Stapel geleitet.In order to remove the waste heat generated during the generation of electricity in the fuel cells, suitable components through which deionized water flows are used in the fuel cell stacks. The supply and discharge of the cooling water passed through the stack is usually also via the connection plates at the ends of the stack. To do this, the deionized water is fed lengthways through the stack.

In der Nähe der Anschlussplatten an den Enden des Brennstoffzellenstapels befindet sich in einem betriebsgasfreien Anschlussraum jeweils eine Kontaktvorrichtung, die den Brennstoffzellenstapel elektrisch kontaktiert und den Strom über Anschlussfahnen aus dem Bennstoffzellenstapel herausleitet. Die Kontaktvorrichtung besteht z.B. aus einer Kontaktplatte, die in elektrischem Kontakt mit einer den Brennstoffzellenstapel abschliessenden Pol- oder Bipolarplatte steht und ggfs. Halteelemente, z.B. aus einem Elastomer, aufweist, mit denen sie an dem Brennstoffzellenstapel gehalten und/oder ausgerichtet wird. Zur Verbesserung der elektrischen Anbin- dung zwischen der Kontaktplatte und der Pol- oder Bipolarplatte kann die Kontaktvorrichtung weitere Bauteile wie z.B. Kontaktfederbleche oder Kontaktfolien umfassen. Alle diese Bauteile sollen den Strom möglichst gut leiten und bestehen daher meist aus einem elektrisch gut leitenden Material, z.B. aus Kupfer oder einer Kupferlegierung.In the vicinity of the connection plates at the ends of the fuel cell stack there is a contact device in an operating gas-free connection space, which makes electrical contact with the fuel cell stack and leads the current out of the fuel cell stack via connection lugs. The contact device is e.g. from a contact plate that is in electrical contact with a pole or bipolar plate that closes off the fuel cell stack and, if necessary, holding elements, e.g. made of an elastomer, with which it is held and / or aligned on the fuel cell stack. To improve the electrical connection between the contact plate and the pole or bipolar plate, the contact device can include further components such as Include contact spring plates or contact foils. All of these components are intended to conduct the current as well as possible and are therefore usually made of an electrically highly conductive material, e.g. made of copper or a copper alloy.

Bei der Montage dieser Bauteile ist prinzipiell damit zu rechnen, dass sie nass werden und auch der an sich betriebs- gasfreie Anschlussräum, in dem sie eingebaut werden, nicht trocken bleibt. Erschwerend kommt hinzu, dass die Atmosphäre, in der die Bauteile eingebaut sind, im Laufe der Zeit ihren Wasserdampfgehalt ändert. Dies kann bei Temperaturwechseln bis zum Auskondensieren der Feuchtigkeit auf den Bauteilen führen.When assembling these components, it is generally to be expected that they will get wet and the connection gas-free connection space in which they will be installed will not remain dry. To make matters worse, the atmosphere in which the components are installed changes their water vapor content over time. In the event of temperature changes, this can lead to moisture condensing on the components.

Zur Vermeidung von Wasseransammlungen in dem Anschlussraum der Kontaktvorrichtung muss eine kontinuierliche, zumindest regelmäßige Trocknung der Atmosphäre im Rahmen von Servicemaßnahmen an den Brennstoffzellenstapeln erfolgen. Die Trocknung kann z.B. durch Spülung des Raumes mit trockenen Gasen wie Stickstoff oder durch Anlegen von Vakuum erfolgen. Diese Verfahren sind jedoch zeit- und kostenaufwendig. Es ist deshalb Aufgabe vorliegender Erfindung, eine Kontaktvorrichtung zu schaffen, die die Ausbringung von Wasser aus dem Anschlussraum vereinfacht.To avoid water accumulation in the connection space of the contact device, the atmosphere must be dried continuously, at least regularly, as part of service measures on the fuel cell stacks. Drying can be carried out, for example, by flushing the room with dry gases such as nitrogen or by applying a vacuum. However, these procedures are time consuming and costly. It is therefore an object of the present invention to provide a contact device which simplifies the discharge of water from the connection space.

Die Lösung dieser Aufgabe gelingt erfindungsgemäß durch eine Kontaktvorrichtung gemäß Anspruch 1. Ein Brennstoffzellenstapel bzw. ein Brennstoffzellenblock mit einer derartigen Kontaktvorrichtung ist Gegenstand des Anspruches 15 bzw. 16. Vorteilhafte Ausgestaltungen der Erfindung sind jeweils Gegenstand der Unteransprüche.This object is achieved according to the invention by a contact device according to claim 1. A fuel cell stack or a fuel cell block with such a contact device is the subject of claims 15 and 16. Advantageous embodiments of the invention are the subject of the dependent claims.

Die Erfindung geht von der Überlegung aus, dass die Oberfläche der Kontaktvorrichtung Poren aufweist. Diese Poren besitzen insbesondere bei metallischen Oberflächen hydrophile Eigenschaften. Wasser auf der Oberfläche der Kontaktvorrichtung wird damit in Poren regelrecht hineingesaugt wie in eine Kapillare.The invention is based on the consideration that the surface of the contact device has pores. These pores have hydrophilic properties, particularly on metallic surfaces. Water on the surface of the contact device is literally sucked into pores like a capillary.

Durch die auf der Oberfläche der Kontaktvorrichtung vorgesehene hydrophobe (wasserabstoßende) Oberflächenschicht werden diese Poren "verschlossen". Je feiner eine Pore ist, umso größere Kräfte sind aufzubringen, um die Flüssigkeit in die Pore hineinzudrücken. Selbst ein Kondenswassertropfen, der sich in der Pore bildet, wandert aus ihr heraus, je größer er wird. Das Wasser verbleibt somit unter Tröpfchenbildung an der Oberfläche der Kontaktvorrichtung. Die Wassertröpfchen weisen eine nur sehr gering Haftung auf dieser Oberfläche auf und können von dort mit einem sehr geringen Gasstrom entfernt werden. Die Ausbringung des Wassers aus dem Anschlussraum kann hierdurch wesentlich vereinfacht und kostengünstiger gestaltet werden.These pores are "closed" by the hydrophobic (water-repellent) surface layer provided on the surface of the contact device. The finer a pore, the greater the forces that must be applied to force the liquid into the pore. Even a drop of condensed water that forms in the pore migrates out of it, the larger it becomes. The water thus remains on the surface of the contact device, forming droplets. The water droplets have very little adhesion to this surface and can be removed from there with a very low gas flow. The discharge of the water from the connection space can hereby be made considerably easier and less expensive.

Wenn die Kontaktvorrichtung Halteelemente, insbesondere aus einem Elastomer, zur Halterung und/oder Ausrichtung der Kontaktvorrichtung an einem Brennstoffzellenstapel aufweist, kann die Ausbringung des Wassers dadurch noch vereinfacht werden, dass diese Halteelemente ebenfalls zumindest teilweise mit der hydrophoben Oberflächenschicht versehen sind.If the contact device has holding elements, in particular made of an elastomer, for holding and / or aligning the contact device on a fuel cell stack, the discharge of the water can thereby be simplified even further that these holding elements are also at least partially provided with the hydrophobic surface layer.

Eine gute Stromleitfähigkeit der Kontaktvorrichtung und gleichzeitig eine gute Ausbringung des Wassers aus dem Anschlussraum ist dadurch möglich, dass die Dicke der hydrophoben Oberflächenschicht im Bereich elektrischer Verbindungsstellen, z.B. zwischen der Kontaktvorrichtung und einer anliegenden Pol- oder Bipolarplatte, auf ein Optimum zwischen einem niedrigen elektrischen Übergangswiderstand und einer hohen Hydrophobizität eingestellt ist.A good current conductivity of the contact device and at the same time a good discharge of the water from the connection space is possible in that the thickness of the hydrophobic surface layer in the area of electrical connection points, e.g. between the contact device and an adjacent pole or bipolar plate, is set to an optimum between a low electrical contact resistance and a high hydrophobicity.

In einer vorteilhaften Ausgestaltung der Erfindung enthält die hydrophobe Oberflächenschicht Polytetrafluorethylen (PTFE) . Dieses Material zeichnet sich durch gute Haftbarkeit auf Metall- oder Elastomerschichten aus. An den elektrischen Verbindungsstellen besteht die Oberflächenschicht zur Erzielung eines geringen elektrischen Übergangswiderstandes vorteilhafterweise aus einem PTFE-Metall oder PTFE-Kohle- Gemisch.In an advantageous embodiment of the invention, the hydrophobic surface layer contains polytetrafluoroethylene (PTFE). This material is characterized by good adhesion to metal or elastomer layers. At the electrical connection points, the surface layer advantageously consists of a PTFE metal or PTFE-carbon mixture in order to achieve a low electrical contact resistance.

In einer besonders vorteilhaften Ausgestaltung besteht die hydrophobe Oberflächenschicht aus einem in einem Lösemittel lösbaren hydrophobierenden Material. Dieses Material kann in gelöstem Zustand auf die Oberfläche der Kontaktvorrichtung aufgebracht und damit sehr dünne Schichten erzielt werden. Hierdurch kann zum einen die für die einfache Wasserausbringung benötigte Hydrophobizität der Oberfläche der Kontaktvorrichtung, zum anderen aber auch ein geringer Übergangswiderstand an den elektrischen Verbindungsstellen gewährleistet werden. Der Kontaktvorrichtung kann somit eine gute Stromleitfähigkeit mitgegeben werden, die z.B. mit reinen PTFE- Beschichtungen nicht erreichbar ist. Die hydrophobe Oberflächenschicht aus dem in einem Lösemittel lösbaren, hydrophobierenden Material ist deshalb insbesondere für elektrische Verbindungsstellen geeignet. Bevorzugt besteht das lösbare, hydrophobierende Material ganz oder teilweise aus einem amorphen Fluoropolymer, alternativ eignen sich auch Polisiloxanverbindungen oder Alkylsilane. Diese Materialien weisen eine besonderes gute Haftbarkeit auf Metallen auf.In a particularly advantageous embodiment, the hydrophobic surface layer consists of a hydrophobizing material that is soluble in a solvent. This material can be applied to the surface of the contact device in the dissolved state and very thin layers can thus be achieved. In this way, on the one hand the hydrophobicity of the surface of the contact device required for the simple application of water, and on the other hand also a low contact resistance at the electrical connection points can be ensured. The contact device can thus be given good current conductivity, which cannot be achieved, for example, with pure PTFE coatings. The hydrophobic surface layer made of the solvent-soluble, hydrophobizing material is therefore particularly suitable for electrical connection points. The detachable, hydrophobizing material preferably consists entirely or partially of an amorphous fluoropolymer, alternatively polisiloxane compounds or alkylsilanes are also suitable. These materials have a particularly good adhesion to metals.

Unter den amorphen Fluoropolymeren eignen sich insbesondere amorphe Modifikationen von Teflon. Dieses Material kann in geeigneten Lösungsmitteln bezogen und vor Gebrauch auf eine optimale Konzentration verdünnt werden. Die Lösung kann dann durch ein übliches Aufbringverfahren wie Sprühen, Wischen, Pinseln, Tauchen, Drucken auf die Korrosionsschutzschicht aufgebracht, das Lösungsmittel verdampft und das verbleibende Material ggf. durch einen Temperaturschritt bei erhöhter Temperatur auf der Korrosionsschutzschicht immobilisiert werden. Nach dem Verdampfen des Lösungsmittels bleibt ein sehr dünner Teflonfilm zurück, der insbesondere die Innenflächen der Poren bedeckt.Amorphous modifications of Teflon are particularly suitable among the amorphous fluoropolymers. This material can be obtained in suitable solvents and diluted to an optimal concentration before use. The solution can then be applied to the corrosion protection layer by a customary application method such as spraying, wiping, brushing, dipping, printing, the solvent evaporated and the remaining material, if appropriate, immobilized on the corrosion protection layer by a temperature step at elevated temperature. After the solvent has evaporated, a very thin Teflon film remains, which in particular covers the inner surfaces of the pores.

Die erfindungsgemäße Kontaktvorrichtung eignet sich besonders vorteilhaft zum Abgreifen des von einem Brennstoffzellenstapel erzeugten Stromes.The contact device according to the invention is particularly advantageously suitable for tapping the current generated by a fuel cell stack.

Weiterhin kann sie vorteilhaft bei einem Brennstoffzellenblock mit mehreren BrennstoffZellenstapeln zur elektrischen Verbindung von zumindest zwei der Brennstoffzellenstapel genutzt werden.Furthermore, it can advantageously be used in a fuel cell block with a plurality of fuel cell stacks for the electrical connection of at least two of the fuel cell stacks.

Die Erfindung sowie weitere vorteilhafte Ausgestaltungen der Erfindung gemäß Merkmalen der Unteransprüche werden im Folgenden anhand eines schematisch ausgeführten Ausführungsbei- spieles in den Figuren näher erläutert; darin zeigen:The invention and further advantageous refinements of the invention according to the features of the subclaims are explained in more detail below with reference to a schematically executed exemplary embodiment in the figures; show in it:

FIG 1 einen Querschnitt durch einen Brennstoffzellenstapel mit einer erfindungsgemäßen Kontaktvorrichtung; FIG 2 einen Teil der Kontaktvorrichtung von FIG 1 in vergrößerter Darstellung.1 shows a cross section through a fuel cell stack with a contact device according to the invention; 2 shows a part of the contact device of Figure 1 in an enlarged view.

Ein in FIG 1 dargestellter Brennstoffzellenstapel 1 besteht aus mehreren jeweils abwechselnd aufeinandergestapelten Membran-Elektroden-Einheiten 3 und Bipolarplatten 5 und wird durch eine Bipolarplatte 5a abgeschlossen. Eine Membran- Elektroden-Einheit 3 besteht hierbei jeweils aus einer Anode 7, einer Membran 9 und einer Kathode 11. Die Membran- Elektroden-Einheiten 3 und die Bipolarplatten 5, 5a sind in Dichtungen 13 gelagert.A fuel cell stack 1 shown in FIG. 1 consists of several membrane electrode units 3 and bipolar plates 5, which are alternately stacked one on top of the other, and is closed off by a bipolar plate 5a. A membrane electrode unit 3 consists of an anode 7, a membrane 9 and a cathode 11. The membrane electrode units 3 and the bipolar plates 5, 5a are mounted in seals 13.

Während des Betriebs des Brennstoffzellenstapels 1 strömt befeuchteter Wasserstoff in die Anodengasräume 23, die jeweils zwischen der Anode 7 einer Membran-Elektroden-Einheit 3 und einer anliegenden Bipolarplatte 5 angeordnet sind. Außerdem strömt mit Wasser befeuchteter Sauerstoff in die Kathodengas- räume 25, die jeweils zwischen der Kathode 11 einer Membran- Elektroden-Einheit 3 und einer anliegenden Bipolarplatte 5 angeordnet sind. Im Fall der abschließenden Bipolarplatte 5a werden nur die Kathodengasräume 25 mit befeuchtetem Sauerstoff beströmt. Die den Kathodengasräumen 25 abgewandte Seite der Bipolarplatte 5a grenzt an einen Anschlussraum 49, der frei von den Betriebsgasen Wasserstoff und Sauerstoff ist.During the operation of the fuel cell stack 1, humidified hydrogen flows into the anode gas spaces 23, which are each arranged between the anode 7 of a membrane electrode unit 3 and an adjacent bipolar plate 5. In addition, oxygen moistened with water flows into the cathode gas spaces 25, which are each arranged between the cathode 11 of a membrane electrode unit 3 and an adjacent bipolar plate 5. In the case of the final bipolar plate 5a, only the cathode gas spaces 25 are flowed with with humidified oxygen. The side of the bipolar plate 5a facing away from the cathode gas spaces 25 borders on a connection space 49 which is free of the operating gases hydrogen and oxygen.

Zum Abtransport der Reaktionswärme strömt während des Betriebs des Brennstoffzellenstapels 1 Kühlwasser aus einem A- xialkanal 27 in die Hohlräume 19 der Bipolarplatten 5 bzw. 5a. Die durch die Bipolarplatte 5 bzw. 5a in deren Hohlräume 19 einströmende Reaktionswärme wird vom Kühlwasser aufgenommen, das im weiteren Verlauf in einen weiteren Axialkanal 31 strömt und von dort aus dem Brennstoffzellenstapel 1 abgeführt wird.To remove the heat of reaction, cooling water flows from an axial channel 27 into the cavities 19 of the bipolar plates 5 and 5a during operation of the fuel cell stack 1. The heat of reaction flowing into the cavities 19 through the bipolar plate 5 or 5a is absorbed by the cooling water, which flows further into another axial channel 31 and is removed from there from the fuel cell stack 1.

Der Abgriff des von dem Brennstoffzellenstapel 1 erzeugten Stromes erfolgt mit Hilfe einer den Anschlussraum 49 abschließenden, die abschließende Bipolarplatte 5a elektrisch kontaktierenden Kontaktvorrichtung 4. Diese umfasst eine Kontaktplatte 42, die über Kontaktfedern 43 und eine Kontaktfolie 44 mit der Bipolarplatte 5a in elektrischem Kontakt steht. Die Bauteile 42, 43, 44 bestehen zur Gewährleistung einer besonders guten Leitfähigkeit in ihrem Grundmaterial aus Kupfer oder einer Kupferlegierung. Die Kontaktfedern 43 dienen zum Ausgleich von Toleranzen zwischen der Kontaktplatte 42 und dem Brennstoffzellenstapel 1, die Kontaktfolie 44 bewirkt einen besonders geringen Kontaktwiderstand zwischen der Bipolarplatte 5a und den Kontaktfedern 43.The current generated by the fuel cell stack 1 is tapped electrically with the aid of a bipolar plate 5a which closes the connection space 49 and closes the terminal Contacting contact device 4. This comprises a contact plate 42, which is in electrical contact with the bipolar plate 5a via contact springs 43 and a contact foil 44. The components 42, 43, 44 consist of copper or a copper alloy in their base material to ensure a particularly good conductivity. The contact springs 43 serve to compensate for tolerances between the contact plate 42 and the fuel cell stack 1, the contact film 44 brings about a particularly low contact resistance between the bipolar plate 5a and the contact springs 43.

Wie in Detail aus FIG 2 ersichtlich ist, sind die Kontaktplatte 42, die Kontaktfedern 43 und die Kontaktfolie 44 auf ihrer Oberfläche mit einer hydrophoben Oberflächenschicht 45 versehen. Ein besonders geringer Übergangswiderstand zwischen der hydrophoben Oberflächenschicht 45 und dem Grundmaterial der Kontaktplatte 42, der Kontaktfedern 43 bzw. der Kontaktfolie 44 wird dadurch erzielt, dass zusätzlich zwischen dem Grundmaterial und der hydrophoben Oberflächenschicht 45 eine hochleitfähige Kontaktschicht 46 aus einem oder mehreren E- delmetallen, insbesondere aus Gold und Nickel, vorgesehen ist.As can be seen in detail from FIG. 2, the contact plate 42, the contact springs 43 and the contact foil 44 are provided on their surface with a hydrophobic surface layer 45. A particularly low contact resistance between the hydrophobic surface layer 45 and the base material of the contact plate 42, the contact springs 43 or the contact film 44 is achieved in that, in addition, a highly conductive contact layer 46 made of one or more precious metals between the base material and the hydrophobic surface layer 45, in particular made of gold and nickel.

Die Kontaktvorrichtung 4 weist ferner Halteelemente 47 aus einem Elastomer zur Halterung und Ausrichtung der Kontaktvorrichtung 4 am Brennstoffzellenstapel 1 auf, die auch zur Abdichtung des Anschlussraumes 49 gegenüber dem Axialkanal 27 bzw. 31 dienen. Durch den Elastomerwerkstoff ist außerdem ein Ausgleich von Toleranzen in dem Brennstoffzellenstapel 1 möglich. Die Halteelemente 47 sind teilweise ebenfalls mit einer hydrophoben Oberflächenschicht 45 versehen.The contact device 4 also has holding elements 47 made of an elastomer for holding and aligning the contact device 4 on the fuel cell stack 1, which also serve to seal the connection space 49 with respect to the axial channel 27 or 31. The elastomer material also makes it possible to compensate for tolerances in the fuel cell stack 1. The holding elements 47 are also partially provided with a hydrophobic surface layer 45.

Durch die hydrophobe Oberflächenschicht 45 werden die an der Oberfläche der Kontaktvorrichtung 4 bzw. der Kontaktplatte 42, der Kontaktfedern 43, der Kontaktfolie 44 und der Halteelemente 47 vorhandenen Poren verschlossen. Kommt Wasser auf die Oberfläche der Kontaktvorrichtung, so kommt es zu Tropf- chenbildung, wobei die Tröpfchen nur eine geringe Haftung auf der Oberfläche aufweisen und mit einem nur geringen Gasstrom aus dem Anschlussraum 49 und damit aus dem Brennstoffzellenstapel 1 ausgebracht werden können.The pores present on the surface of the contact device 4 or the contact plate 42, the contact springs 43, the contact film 44 and the holding elements 47 are closed by the hydrophobic surface layer 45. If water comes onto the surface of the contact device, dripping Chenbildung, wherein the droplets have little adhesion to the surface and can be applied with a small gas flow from the connection space 49 and thus from the fuel cell stack 1.

Die hydrophobe Oberflächenschicht besteht bevorzugt aus einer amorphen Modifikation von Teflon (zum Beispiel einem amorphen Copolymer aus 65 - 99 Mol % Perfluoro-2, 2-Dimethyl-l, 3-Dioxol mit einer Komplementärmenge von Tetrafluorethylen, unter dem Produktnamen Teflon®AF von DuPont Fluoroproducts erhältlich) . Dieses Material ist aufgrund seiner guten Lösbarkeit in Lösemitteln mit geringer Dicke auf die Bauteile 42,43,44 der Kontaktvorrichtung 4 aufbringbar und eignet sich somit insbesondere für die elektrischen Verbindungsstellen 48 sowohl zwischen den einzelnen Bauteilen 42,43,44 der Kontaktvorrichtung 4 sowie von der Kontaktvorrichtung 4 zu der Bipolarplatte 5a.The hydrophobic surface layer preferably consists of an amorphous modification of Teflon (for example an amorphous copolymer of 65-99 mol% perfluoro-2, 2-dimethyl-1,3-dioxol with a complementary amount of tetrafluoroethylene, under the product name Teflon®AF from DuPont Fluoroproducts available). This material can be applied to the components 42, 43, 44 of the contact device 4 due to its good solubility in solvents with a small thickness and is therefore particularly suitable for the electrical connection points 48 both between the individual components 42, 43, 44 of the contact device 4 and of Contact device 4 to the bipolar plate 5a.

Um einen guten Stromfluss im Bereich der elektrischen Verbindungsstellen 48 zwischen der Kontaktplatte 42, den Kontaktfedern 43, der Kontaktfolie 44 und der angrenzenden Bipolarplatte 5 und gleichzeitig eine einfache Ausbringung von Wasser aus dem Anschlussraum 49 zu ermöglichen, ist die Dicke der hydrophoben Oberflächenschicht 45 aus amorphem Teflon an diesen Verbindungsstellen 48 auf ein Optimum zwischen einem niedrigem Kontaktwiderstand und einer hohen Hydrophobizität eingestellt. Dies ist insbesondere dadurch möglich, dass die hydrophobe Oberflächenschicht 45 an diesen elektrischen Verbindungsstellen 48 eine Dicke im Bereich von 0,1 nm bis 10 nm, insbesondere 0,5 nm bis 0,7 nm, aufweist. Hierzu hat sich eine Verdünnung des amorphen Teflon mit einem Lösungsmittel im Verhältnis von 1:200 als geeignet erwiesen. Die dadurch erzielbare dünne Schicht auf der Kontaktfolie 44 kann z.B. von den Kontaktfedern 43 mechanisch zur Seite geschoben werden. In den Poren bleibt dann das Teflon zurück und bewirkt die gewünschte Hydrophobizität, während die Kontaktstellen auf der Kontaktfolie 44 frei von Teflon sind und somit einen nur geringen Übergangswiderstand aufweisen. Im Bereich außerhalb der elektrischen Verbindungsstellen 48, z.B. auf den Elastomer-Halteelementen 47, kann das amorphe Teflon unverdünnt aufgetragen werden. Die Dicke der hydrophoben Schicht beträgt dort vorteilhafterweise 0,01 μm bis 100 μm, insbesondere 0,01 μm bis 1 μm. In order to allow a good current flow in the area of the electrical connection points 48 between the contact plate 42, the contact springs 43, the contact film 44 and the adjacent bipolar plate 5 and at the same time a simple dispensing of water from the connection space 49, the thickness of the hydrophobic surface layer 45 is made of amorphous Teflon at these connection points 48 is set to an optimum between a low contact resistance and a high hydrophobicity. This is possible in particular in that the hydrophobic surface layer 45 has a thickness in the range from 0.1 nm to 10 nm, in particular 0.5 nm to 0.7 nm, at these electrical connection points 48. A dilution of the amorphous Teflon with a solvent in a ratio of 1: 200 has proven to be suitable for this. The thin layer that can be achieved on the contact foil 44 can be mechanically pushed aside by the contact springs 43, for example. The Teflon then remains in the pores and brings about the desired hydrophobicity, while the contact points on the contact film 44 are free of Teflon and thus have only a low contact resistance. In the area outside of the electrical connection points 48, for example on the elastomer holding elements 47, the amorphous Teflon can be applied undiluted. The thickness of the hydrophobic layer there is advantageously 0.01 μm to 100 μm, in particular 0.01 μm to 1 μm.

Claims

Patentansprüche claims 1. Kontaktvorrichtung (4) zur elektrischen Kontaktierung eines Brennstoffzellenstapels (1) , wobei die Kontaktvorrichtung an ihrer Oberfläche zumindest teilweise mit einer hydrophoben Oberflächenschicht (45) versehen ist.1. Contact device (4) for electrically contacting a fuel cell stack (1), the contact device being at least partially provided on its surface with a hydrophobic surface layer (45). 2. Kontaktvorrichtung (4) nach Anspruch 1 wobei die Kontaktvorrichtung Halteelemente (47) , insbesondere aus einem Elastomer, zur Halterung und/oder Ausrichtung der Kontaktvorrichtung (4) an einem Brennstoffzellenstapel (1) aufweist, die zumindest teilweise mit der hydrophoben Oberflächenschicht (45) versehen sind.2. Contact device (4) according to claim 1, wherein the contact device has holding elements (47), in particular made of an elastomer, for holding and / or aligning the contact device (4) on a fuel cell stack (1), which at least partially with the hydrophobic surface layer (45 ) are provided. 3. Kontaktvorrichtung (4) nach Anspruch 1, wobei die Dicke der hydrophoben Oberflächenschicht (45) im Bereich elektrischer Verbindungsstellen (48) auf ein Optimum zwischen einem niedrigen elektrischen Übergangswiderstand und einer hohen Hydrophobizität eingestellt ist.3. Contact device (4) according to claim 1, wherein the thickness of the hydrophobic surface layer (45) in the region of electrical connection points (48) is set to an optimum between a low electrical contact resistance and a high hydrophobicity. 4. Kontaktvorrichtung (4) nach einem der vorhergehenden Ansprüche, wobei die hydrophobe Oberflächenschicht (45) Poly- tetrafluorethylen (PTFE) enthält.4. Contact device (4) according to one of the preceding claims, wherein the hydrophobic surface layer (45) contains poly-tetrafluoroethylene (PTFE). 5. Kontaktvorrichtung (4) nach Anspruch 4, wobei die hydrophobe Oberflächenschicht (45) an elektrischen Verbindungsstellen (48) aus einem PTFE-Metall- oder PTFE- Kohle-Gemisch besteht.5. Contact device (4) according to claim 4, wherein the hydrophobic surface layer (45) at electrical connection points (48) consists of a PTFE-metal or PTFE-carbon mixture. 6. Kontaktvorrichtung (4) nach einem der Ansprüche 1 bis 3 wobei die hydrophobe Oberflächenschicht (45) aus einem in einem Lösemittel lösbaren, hydrophobierenden Material besteht.6. Contact device (4) according to one of claims 1 to 3, wherein the hydrophobic surface layer (45) consists of a solvent-soluble, hydrophobizing material. 7. Kontaktvorrichtung (4) nach Anspruch 6 wobei das hydrophobierende Material ganz oder teilweise aus einem amorphem Fluoropolymer besteht. 7. Contact device (4) according to claim 6, wherein the hydrophobizing material consists entirely or partially of an amorphous fluoropolymer. 8. Kontaktvorrichtung (4) nach Anspruch 7 wobei das amorphe Fluoropolymer eine amorphe Modifikation von Teflon ist.8. Contact device (4) according to claim 7, wherein the amorphous fluoropolymer is an amorphous modification of Teflon. 9. Kontaktvorrichtung (4) nach Anspruch 6 wobei das hydrophobierende Material ganz oder teilweise aus einer Polisiloxanverbindung oder aus Alkylsilanen besteht.9. Contact device (4) according to claim 6, wherein the hydrophobizing material consists entirely or partially of a polisiloxane compound or of alkylsilanes. 10. Kontaktvorrichtung (4) nach einem der Ansprüche 6 bis 9, mit einer Dicke der hydrophoben Oberflächenschicht (45) im Bereich einer elektrischen Verbindungsstelle (48) im Bereich von 0,1 nm bis 10 nm, insbesondere 0,5 nm bis 0,7 nm.10. Contact device (4) according to one of claims 6 to 9, with a thickness of the hydrophobic surface layer (45) in the region of an electrical connection point (48) in the range from 0.1 nm to 10 nm, in particular 0.5 nm to 0, 7 nm. 11. Kontaktvorrichtung (4) nach einem der Ansprüche 7 bis 10, mit einer Dicke der hydrophoben Oberflächenschicht (45) außerhalb des Bereiches einer elektrischen Verbindungsstelle11. Contact device (4) according to one of claims 7 to 10, with a thickness of the hydrophobic surface layer (45) outside the region of an electrical connection point (48) im Bereich von 0,01 μm bis 100 μm, insbesondere 0,01 μm bis 1 μm.(48) in the range from 0.01 μm to 100 μm, in particular 0.01 μm to 1 μm. 12. Kontaktvorrichtung (4) nach Anspruch 1, wobei die Kontaktvorrichtung (4) in ihrem Grundmaterial aus Kupfer oder einer Kupferlegierung besteht.12. Contact device (4) according to claim 1, wherein the contact device (4) consists in its base material of copper or a copper alloy. 13. Kontaktvorrichtung (4) nach Anspruch 12, mit einer hoch- leitfähigen Kontaktschicht (46) aus einem oder mehreren Edelmetallen, insbesondere aus Gold und Nickel, zwischen dem Grundmaterial und der hydrophoben Oberflächenschicht (45) .13. Contact device (4) according to claim 12, with a highly conductive contact layer (46) made of one or more precious metals, in particular gold and nickel, between the base material and the hydrophobic surface layer (45). 14. Kontaktvorrichtung (4) nach zumindest einem der vorhergehenden Ansprüche, mit mehreren in elektrischem Kontakt stehenden und jeweils zumindest teilweise mit einer hydrophoben Oberflächenschicht (45) versehenen Bauteilen (42,43,44). 14. Contact device (4) according to at least one of the preceding claims, having a plurality of components (42, 43, 44) which are in electrical contact and each at least partially provided with a hydrophobic surface layer (45). 15. Brennstoffzellenstapel (1) mit einer Kontaktvorrichtung (4) nach zumindest einem der vorhergehenden Ansprüche zum Abgreifen des von dem Brennstoffzellenstapel (1) erzeugten Stromes.15. Fuel cell stack (1) with a contact device (4) according to at least one of the preceding claims for tapping the current generated by the fuel cell stack (1). 16. Brennstoffzellenblock mit mehreren Brennstoffzellensta- peln (1) und mit einer Kontaktvorrichtung (4) nach einem der Ansprüche 1 bis 14 zur elektrischen Verbindung von zumindest zwei der Brennstoffzellenstapel (1) . 16. Fuel cell block with a plurality of fuel cell stacks (1) and with a contact device (4) according to one of claims 1 to 14 for the electrical connection of at least two of the fuel cell stacks (1).
EP04726996A 2003-05-26 2004-04-13 Contact device and fuel cell stack or block comprising one such contact device Withdrawn EP1627439A2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE10323881A DE10323881A1 (en) 2003-05-26 2003-05-26 Contact device and fuel cell stack or fuel cell block with such a contact device
PCT/EP2004/003869 WO2004107474A2 (en) 2003-05-26 2004-04-13 Contact device and fuel cell stack or block comprising one such contact device

Publications (1)

Publication Number Publication Date
EP1627439A2 true EP1627439A2 (en) 2006-02-22

Family

ID=33482179

Family Applications (1)

Application Number Title Priority Date Filing Date
EP04726996A Withdrawn EP1627439A2 (en) 2003-05-26 2004-04-13 Contact device and fuel cell stack or block comprising one such contact device

Country Status (5)

Country Link
US (1) US8067131B2 (en)
EP (1) EP1627439A2 (en)
KR (1) KR20060013423A (en)
DE (1) DE10323881A1 (en)
WO (1) WO2004107474A2 (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102004018620A1 (en) * 2004-04-16 2005-11-03 Volkswagen Ag Electric current deflector plate for fuel cell stack has contacting auxiliary elevations facing towards side of end plate, where elevations run parallel to each other and fit into material of end plate
EP1739782A1 (en) * 2005-06-28 2007-01-03 Siemens Aktiengesellschaft Method for operating an electrolytic cell or fuel cell battery and electrochemical device with such a battery
US10516182B2 (en) * 2009-08-21 2019-12-24 Iucf-Hyu (Industry-University Cooperation Foundation Hanyang University) Polymer ion exchange membrane and method of preparing same
US9678501B2 (en) * 2013-01-08 2017-06-13 Bloom Energy Corporation Serialization of fuel cell components

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4938833A (en) * 1982-09-30 1990-07-03 Engelhard Corporation Process for making film-bonded fuel cell interfaces
US4728585A (en) 1986-12-24 1988-03-01 International Fuel Cells Corporation Fuel cell stack with combination end-pressure plates
IT1270878B (en) 1993-04-30 1997-05-13 Permelec Spa Nora IMPROVED ELECTROCHEMISTRY CELL USING ION EXCHANGE MEMBRANES AND METAL BIPOLAR PLATES
US6001502A (en) * 1997-06-27 1999-12-14 Plug Power, L.L.C. Current conducting end plate of fuel cell assembly
US6203936B1 (en) * 1999-03-03 2001-03-20 Lynntech Inc. Lightweight metal bipolar plates and methods for making the same
US5945232A (en) 1998-04-03 1999-08-31 Plug Power, L.L.C. PEM-type fuel cell assembly having multiple parallel fuel cell sub-stacks employing shared fluid plate assemblies and shared membrane electrode assemblies
CN1190859C (en) 1998-08-20 2005-02-23 松下电器产业株式会社 Fuel cell and manufacture thereof
ATE389243T1 (en) 1999-01-25 2008-03-15 Asahi Glass Co Ltd SOLID POLYMER TYPE FUEL CELL AND PRODUCTION THEREOF
US6440594B1 (en) * 1999-06-17 2002-08-27 California Institute Of Technology Aerosol feed direct methanol fuel cell
US6828054B2 (en) * 2000-02-11 2004-12-07 The Texas A&M University System Electronically conducting fuel cell component with directly bonded layers and method for making the same
US6824874B1 (en) * 2000-08-23 2004-11-30 Dana Corporation Insulator and seal for fuel cell assemblies
US7235315B2 (en) * 2003-12-16 2007-06-26 Ballard Power Systems Inc. Electrochemical fuel cell stack having a plurality of integrated voltage reversal protection diodes

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2004107474A2 *

Also Published As

Publication number Publication date
DE10323881A1 (en) 2004-12-23
KR20060013423A (en) 2006-02-09
WO2004107474A3 (en) 2005-12-22
US8067131B2 (en) 2011-11-29
WO2004107474A2 (en) 2004-12-09
US20070054163A1 (en) 2007-03-08

Similar Documents

Publication Publication Date Title
DE112005002974B4 (en) A method of increasing the bond strength between elements of a fuel cell membrane electrode assembly to be bonded by means of an adhesive
DE102006054797B4 (en) Flow field plate with high electrochemical stability and improved water management and method for its production
DE102008029628B4 (en) Fuel cell stack with low electrical resistance bipolar plate diffusion media assembly and method of making same
EP1453133B1 (en) Fuel cell or electrolyzer and process for its production
DE102007026339B4 (en) Fuel cell with a flow field plate, method for producing such a flow field plate and use of the aforementioned fuel cell
WO1996018216A1 (en) Polymer electrolyte membrane fuel cell
DE102008038202B4 (en) PEM fuel cell with improved water management and process for its production
DE102013207900A1 (en) Membrane electrode unit and fuel cell with such
DE102007034239A1 (en) Method for forming hydrophilic and electrically conductive layer on bipolar plate for fuel cell, involves preparing composition of material, comprising niobium-doped titanium oxide powder which is formed into layer
DE102007003825A1 (en) Superhydrophilic, nanoporous, electrically conductive coatings for PEM fuel cells
DE102008064086A1 (en) Passivated metal bipolar plates and a process for their production
DE102008059349B4 (en) Fuel cell stack with a device for improved water management
DE102009003074A1 (en) Electrochemical cell for obtaining electrical energy
DE102007022202B4 (en) Fuel cell stack with a non-permeable insert with low contact resistance
DE102009035961A1 (en) Layered electrode for electrochemical cells
EP1627439A2 (en) Contact device and fuel cell stack or block comprising one such contact device
EP3456866A1 (en) Interconnector, method for the preparation of an interconnector and its use
EP1627440B1 (en) Bipolar plate and fuel cell comprising such a bipolar plate
US8771896B2 (en) Fuel cell with current collectors integrated with the solid electrolyte and process for manufacturing such a fuel cell
WO2002027837A2 (en) Method for operating a fuel cell, polymer-electrolyte membrane fuel cell operated according to said method and method for producing the same
DE102013208839A1 (en) Polar plate, fuel cell with such and method for producing the polar plate
DE102004056846A1 (en) Metallic bipolar plate located between adjacent membrane electrodes of vehicular fuel cell, has conductive, inert coating at contact regions, with anti-corrosion coating in other regions
DE112006001838B4 (en) Electrically conductive fluid distribution plate and fuel cell configured therewith
WO2022129279A1 (en) Fuel cell stack and production method
DE10350478B4 (en) fuel cell unit

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20051116

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PL PT RO SE SI SK TR

AX Request for extension of the european patent

Extension state: AL HR LT LV MK

RIN1 Information on inventor provided before grant (corrected)

Inventor name: HAMMERSCHMIDT, ALBERT

Inventor name: MATTEJAT, ARNO

Inventor name: MEHLTRETTER, IGOR

Inventor name: HARTNACK, HERBERT

DAX Request for extension of the european patent (deleted)
RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: SIEMENS AKTIENGESELLSCHAFT

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: SIEMENS AKTIENGESELLSCHAFT

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20161101