DE102007005232A1 - Fuel cell assembly, particularly micro fuel cell, has membrane unit with electrode, which is in form of anode or cathode and current conductor structure has electrically conductive current conductor base body - Google Patents

Abstract

The present invention relates to a fuel cell assembly and a method for the production thereof. The fuel cell arrangement (1) according to the invention comprises: a membrane unit (2) having at least one electrode in the form of an anode (3) and / or a cathode (4) and at least one current collector structure (5) which contains an electrically conductive current collector base body (6), and the Stromableitergrundkörper (6) has a passivation layer (7) with distributed therein single contacts (8), wherein the individual contacts (8) are arranged so that they on the one hand electrically contact a Elrundkörper (6). With the invention it is possible to produce corrosion-resistant and therefore long-term stable fuel cell arrangements in a cost-effective manner.

Description

The The present invention relates to a fuel cell assembly as well a process for their preparation.

One Essential, until today not satisfactorily solved problem in the technical Realization of fuel cells is achieving a low level Contact resistance between a current collector structure (for example a bipolar plate) and a membrane unit with at the same time minimal Corrosion and high long-term stability of the current collector structure. This is best achieved by bipolar plates made of graphite, but in the production of expensive and because of their brittle fracture risk for the mobile Use problems show. It is therefore conceivable composite materials as material for Bipolar plates to use, however, their electrical conductivity is low. Furthermore It is known to use metallic Bi polar plates. Metallic Bipolar plates are then corrosion-resistant if they have an (oxidic) Form passivation layer, which, however, the electrical Contact resistance then again greatly increased.

It Therefore, the object of the present invention is a fuel cell assembly to provide which has a current collector structure, the one high corrosion stability and still has a low contact resistance to a Membrane unit / electrode shows. With the production method according to the invention should be a cost-effective production, also on an industrial scale, to be possible.

These Tasks are solved by the subject matters of the independent claims. This is first a fuel cell assembly containing a membrane unit with at least one electrode in the form of an anode and / or a cathode, and at least one Stromableiterstruktur which an electric conductive Stromableitergrundkörper contains and the current collector body a Passivierungsschicht with distributed therein single contacts having, wherein the individual contacts are arranged so that they on the one hand an electrode and on the other hand, the Stromableitergrundkörper electrically to contact.

The Current collector structure, which is a simple current collector plate or part of a bipolar plate, is constructed according to the invention that this is due to electrical connection to a membrane unit high electrical conductivity the individual contacts has a low contact resistance. in this connection is the basic idea that the individual contacts are spread over the Surface of the Stromableiterstruktur and with the - preferably made of metal - Stromableitergrundkörper in are electrical contact. The individual contacts are here in one introduced insulating coating. This means that the membrane unit or directed to the particular electrode of the membrane unit surface of the Stromableiterstruktur "two-layered" is constructed. To the one are the area distributed individual contacts provided which the actual electrical Make contact. On the other hand, the individual contacts with surrounded by passivated, corrosion-resistant material.

By This "division of responsibilities" is on the one hand Choice of highly conductive and non-corrodible metals for the individual contacts a sufficient total conductivity given, on the other hand, the raw material consumption only on the necessary Dimension limited, there no full-surface Occupancy with, for example, a precious metal must be made. Come in addition a (for example, in mechanical deformation of the current collector structure possible) Replacement of Metal hardly in question, because the area to the current collector base body clearly minimized here. Also a replacement due to tensions different thermal expansion coefficient can be avoided be by the expansion coefficients and the modulus of elasticity, before especially the passivation layer can be adapted very well.

Around the corrosion resistance over long periods to ensure is also a good adaptation of materials and technologies between the electrically conductive Contacts and the isolation area in between. Here may there is no formation of gaps or cracks along which a fabric transport could be done. You would too for one alkaline fuel cell use materials other than for a fuel cell at the ionic conductivity by acid groups is produced.

In The most aggressive alkaline environment could be the footprint the precious metal contacts are with a metal like magnesium, Titanium or zirconium coated, which is a natural oxide layer forms in the interface with the polymer deposited thereon as a corrosion protection layer, very stable opposite a lye attack is. As polymers are particularly suitable polyamide or materials such as bitumen or asphalt.

The Production method according to the invention provides that a Stromableitergrundkörper with in an insulating Coating flat Distributed individual contacts is provided and then the individual contacts in electrical connection with an electrode of the membrane unit to be brought.

This process is also very easy to produce in microstructures and is therefore recommended for the cost-effective industrial production.

One Advantage of the invention is that the electrical, mechanical and chemical properties of the surface coating not in one single material must be optimized, but practically on two materials (insulating coating to compensate for mechanical stress etc. and producing a good electrical conductivity divided by the individual contacts).

So should the contact material of the individual contacts before an urgent good electrical conductivity, adhesion on the current collector body and have a good corrosion resistance. The thermal expansion coefficient and the ductility but this material is of much lesser importance, as always only very small contiguous surfaces with the current collector body are connected. Also the material price can be much higher, without the total costs in the amount to drive, since only a small substrate surface is coated with it (it is therefore even possible Gold for to use the individual contacts).

The Passivation layer, however, does not require any electric conductivity and can for optimum adhesion, ductility and chemical resistance be interpreted. Here, above all, the use of polymers is possible. hereby it becomes possible, for example a sheet with flat distributed individual contacts and one arranged between the individual contacts Passivation to coat and then deform, without that (as in a total coating with the precious metal) defects or Cracks occur. But also in the choice of material for the Stromableitergrundkörper are even greater freedom given. For example, here can be copper or aluminum with a very high conductivity be used. These otherwise so prone to corrosion, but cost-effective and in the non-corroded state, good conductive materials are passed through The insulating layer is covered so that it does not interfere the total conductivity the current collector structure comes. It should also be noted that the corrosion and thus the long-term stability also strong of the operational parameters of the fuel cell (voltage, power density, temperature) and the type of fuel cell (hydrogen PEM, DMFC, DEFC) are dependent. The contact resistance as a function of the contact pressure is in addition to the electrical conductivity of the materials also from the mechanical properties (modulus of elasticity, Compression modulus) and the thickness of the layers (in particular a softer partner, such as a gas diffusion layer, which at the Membrane unit attached) depends. To these requirements can by an appropriate vote of the materials mentioned here to be well reacted.

It It is preferable to ensure that the mean distance between the conductive one Single contacts is so low that the spreading resistance in the membrane unit (electrode or gas diffusion layer) negligible is.

The this arrangement is for Superstructures (membrane units) with or without additional gas diffusion layer used possible. Here is the entire surface the current collector structure can be coated with the individual contacts, or even just a portion of the webs that are in direct contact with the membrane unit stand. As application area, all fuel cells come with planar Cell or stack construction in question, in particular micro fuel cells, Foil fuel cells, portable fuel cells, all suitable for integration into electrical appliances, garments or Vehicles.

Of the necessary contact pressure between the bipolar plate or the Stromableiterstruktur and the electrode or Gas diffusion layer of the fuel cell and the electrical contact resistance is simultaneously reduced by on the surface of the bipolar plate or the Current collector structure finely distributed, raised electrical contacts be applied by a corrosion-resistant coating are surrounded. The mean distance between the individual contacts is so small that the spreading resistance in the electrode or gas diffusion layer is negligible. The prefer made of a precious metal or provided with a stainless steel coating Contacts clearly over the surface the bipolar plate or Stromableiterstruktur addition, it arises in the electrode or gas diffusion layer is a three-dimensional electrical contact, which further reduces the contact resistance. There the microcontact structure only on the webs of the bipolar plates or the current conductor is made and there only a certain Percentage of total surface takes the precious metal can be minimized. Will the Micro-contacts manufactured as structures with a very high aspect ratio (Column structures, "Nano-turf"), arises during the Pressing with the electrode or gas diffusion layer of the fuel cell an independent one Anchoring, so connect The contact pressure can be canceled without the contact resistance increases. In this way, the contact resistance is also due to different thermal Expansion or relative movement due to swelling is not increased. When Substrate for the Micro-contact structure serve metals or metallizations, thereby cost-effective and make light fuel cells.

advantageous Developments of the present invention described in the dependent claims.

A advantageous development provides that the individual contacts contact tips and the contact tips of the individual contacts to increase the contact area with the membrane unit in an electrode and / or gas diffusion layer of the membrane unit friction and / or positively introduced are.

hereby can be based on a contact pressure of the current collector structure on the membrane unit while The operation of the fuel cell may even be omitted altogether become. But at least this can reduce the contact pressure accomplished be. Furthermore is due to the penetration of the individual contacts in the electrode or Gas diffusion layer given an even larger contact area (since lateral contact is given), hereby are even Total contact surfaces possible, which are bigger as the planar plate surface the current collector structure.

A Another advantageous embodiment provides that the individual contacts also partially with a corrosion-resistant coating are coated. For example, (except for the single contact tip, which mandatory with the highly conductive precious metal should be provided) and the foot of the individual contact up to a certain height be coated.

A Another advantageous embodiment provides that the contact tips the individual contacts are plugged into the membrane unit or even so executed are (for example, "mushroom-shaped") that they are the membrane unit in some areas.

The Single contacts can Completely made of precious metal (for example gold, silver or platinum). It is also possible (This is especially true for "sublime" contacts, which are beyond the main level protrude the insulating layer) that the noble metal coating on a core body takes place, which consists of a metal, a polymer material or a ceramic material. This core may also be be an integral part of the Stromableitergrundkörpers. It is too note that the core body, if made of polymer or ceramic, must be electrically conductive or at least a conductive Cover layer, which ultimately has all the individual contacts, z. B. Gold contact points together.

The contact resistance of the individual contacts to the membrane unit should be between 1 Milliohm and 10 illiohm per square centimeter.

The Single contacts should have a diameter between 0.1 microns and 1000 microns, preferably between 1 microns and 100 Micrometer, more preferably between 50 microns and 100 Have micrometer.

The Contact tips can either plan to be the electrical coating, so it overall, it is a single level. When the contact tips over the Level of the membrane unit towards the surface oriented Protruding insulating layer, this protrusion should preferably between 100 microns and 1000 microns.

A Another advantageous embodiment provides that the distance of the Central axes of adjacent individual contacts to each other between 10 Micrometer and 1000 microns. For curved individual contacts is the Central axis determined here by approximation (ie by a linear approximation the centroids the cross-sectional areas).

The Thickness of any gas diffusion layer on the membrane unit is preferably between 50 microns and 1000 microns.

The Gas diffusion layer can increase the conductivity with the rest Membrane unit be mechanically connected, thereby the contact resistance by different thermal expansion or swelling of the involved Partner and the resulting relative movement is not increased.

The provided Stromableiterstruktur is for a variety of different Fuel cell applicable. So the current collector structure part a Stromableiterplatte / monopolar plate or a bipolar plate be. The fuel cell assembly may also be designed planar and a total thickness between 100 microns and 1000 microns (This thickness refers to a membrane unit with monopolar current collector structures arranged on both sides).

According to the invention is also a Fuel cell stack, in which the individual cells from Stromabitern or bipolar plates described above.

In addition, according to the invention is a planar fuel cell assembly of very low height, made of a five-fold Membrane unit with compressed gas diffusion layer exists and due the mechanical / electrical anchoring of current conductors / channel structures with the five-ply Membrane unit can be mounted with very low contact pressure, so that no massive pressure plates or end plates are needed.

In the manufacturing method according to the invention, it is possible that the individual contacts in a Stromableitergrundkörper first inserted or plugged and then subsequently be pressed with the membrane unit so that the contact tips of the individual contacts are frictionally and / or positively anchored in the membrane unit. This results in a particularly good conductivity due to high coverage areas, and the contact pressure can be kept low.

The Single contacts can but also by coating, preferably by coating arise from surveys of Stromplattengrundkörpers. The individual contacts can also grow up in a resist structure, which is subsequently removed becomes, thereby "mushroom forms", which then for example engage behind a gas diffusion layer, possible. There are also many different procedures the microstructuring possible, Individual contacts are also by breeding a "nano-lawn" or by growing up carbon nanotubes (CNT) possible, diverse Applications of CVD or PVD are applicable.

When Advantage of the outstanding single contacts (micro contacts) can be two Aspects are highlighted: reduction of electrical contact resistance and reducing the mechanical contact force to a small To get contact resistance. The fact that you with smaller (or even no) pressure, you can make the fuel cell thinner, lighter To run because no pressure plates needed become.

A Further advantageous embodiment provides that the current collector structure in addition to the electrode a grid-shaped Has structure, which for improved electrical conductivity in areas or pointwise coated with precious metal.

For methanol fuel cells as well as with open cathode sides one uses as Stromableiter expanded metal, mesh, metal mesh or perforated metal foils. In certain constructions, these grids also lie between the membrane electrode assembly / gas diffusion layer and a current collector plate or flowfield plate with larger structure dimensions. The metals themselves are stainless steel, copper, titanium or Nobium.

Most of time These grids are over the entire surface coated with precious metals like gold or platinum. Here you could according to the invention, only the outer regions, respectively in contact with the gas diffusion layer or the current collector plates / flowfields stand locally with precious metal coatings. It makes sense, copper first with a full-surface protective layer from Nobium or titanium to coat and then the point-shaped gold or make platinum contacts.

Further advantageous developments are described in the other dependent claims.

The The present invention will now be explained with reference to several figures. It demonstrate:

1 a fuel cell arrangement according to the invention, which is suitable in particular for film fuel cells,

2 a further embodiment of an inventions to the invention fuel cell assembly, wherein the individual contacts engage behind a gas diffusion layer,

3 a top view and a cross section of a Stromableiterstruktur invention,

4a . 4b Views of another embodiment of a current collector structure,

5 . 6 Stromableiterstrukturen showing single contacts with undercut sections and

7 . 8th Figures for explaining geometric relationships in the individual contacts.

1 shows a fuel cell assembly according to the invention 1 , This contains a membrane unit 2 with two electrodes, namely an anode 3 and a cathode 4 , A separate gas diffusion layer built up on these electrodes is not provided in this embodiment. This is followed in each case by the cathode or from the anode pioneering Stromableiterstrukturen 5 at. These each have an electrically conductive Stromableitergrundkörper 6 on, wherein the Stromableitergrundkörper 6 a passivation coating 7 with individual contacts distributed over the surface 8th having. The individual contacts 8th are arranged so that they on the one hand the corresponding anode 3 or cathode 4 and on the other hand, the respective Stromableitergrundkörper 6 contact electrically.

In the present embodiment, the electrode layer of the MEA is already of such a positivity and thickness, also the channel structure of the Stromablei terstruktur very fine structured (channel widths between 10 microns and 1 millimeter), so that no further gas diffusion layer is needed here and the Stromableiterstruktur (or. Bipolarplatte) with the superficial micro-contact structure, which contains the individual contacts, can be pressed directly onto the electrode layer of the anode or cathode. This is in particular an advantageous structure for thin, foil-like, planar or Mi. krobrennstoffzellen.

2 shows a structure of another embodiment, in which case additionally a gas diffusion layer 9 shown is. The thickness of the gas diffusion layer is mainly at 500 microns.

The individual contacts 8th here have contact tips 8a in which the contact tips for increasing the contact surface with the membrane unit in the gas diffusion layer of the membrane unit are frictionally and positively inserted (even inserted) and engage behind the membrane unit or the associated gas diffusion layer in some areas. In the case of micro contacts produced with a very high aspect ratio (column structures, "nano-turf"), a three-dimensional electrical contact and an independent anchoring are given during the pressing of these individual contacts with the electrodes or gas diffusion layers of the membrane unit, so that subsequently the contact pressure can essentially be canceled, without the contact resistance increasing or considerably increasing. Prerequisite for the cancellation of the contact pressure or a very small contact pressure is in a structure of a fuel cell assembly with a gas diffusion layer, however, that the gas diffusion layer is already mechanically connected to the membrane unit (pressed), it is, for example, five-layer gas diffusion layer. In this way, the contact resistance is not increased by different thermal expansion or relative movement caused by swelling.

3 shows again in an enlarged view the structure of a Stromableiterstruktur invention. On a current collector body 6 , which in the present case is made of metal (aluminum or copper), alternatively, a polymer or composite material having an electrically conductive surface is possible, the individual electrical contacts 8th applied, which are characterized by a high electrical conductivity and corrosion resistance. The individual contacts here are made of gold, whereby the surface of the individual contacts was produced by galvanic deposition. To the individual contacts 8th it turns into a passivation layer 7 produced, which does not have to have good electrical conductivity, important here is a high corrosion resistance. For fuel cells with proton membranes, where the ionic conduction is realized by acid groups, this means, above all, resistance at low pH values. These may be oxides, nitrides, carbides or the like, which are produced by deposition, doping and annealing, oxidation. The passivation layer can also be a thicker deposited layer of a glass or a ceramic or consist of a wide variety of polymers. Important here is only a good adhesion of the contact material (for example, gold in single contact 8th , the passivation layer 7 as well as the Stromableitergrundkörpers 6 ) and a corresponding adjustment of the thermal expansion. Optionally, the passivation layer is made with a defined pressure clamping voltage, so that even with thermal cycles or mechanical stress always a cohesion between the contacts 1 and the passivation layer 2 occurs so that no cracks occur at the interface at which the corrosion of the underlying layer (Stromableitergrundkörper 6 ) could use.

As in 1 , shown on the right side, the individual contacts are partially coated (ie in their "foot") with the passivation layer.

to Savings of precious metal can be taken from the Stromableitergrundkörper itself already out of its surface have protruding surveys, which are then only coated with a precious metal. Besides these core metal bodies can also a corresponding core of the individual contacts to be coated a polymeric material or a ceramic material. It is but to note that the core body, if made of polymer or ceramic, must be electrically conductive or at least a conductive Cover layer, which ultimately has all the individual contacts, z. B. Gold contact points together.

In the present case, the contact resistance of the individual contacts 8th towards a membrane unit 5 milliohms per square centimeter. The individual contacts 8th according to 1 a diameter of 50 microns. The contact tips 8a 100 micrometers protrude from the main surface plane of the current conductor structure (marked with E in 3 right-sided).

The distance of the center axes of adjacent individual contacts to each other is (see distance w in 7 ) present 90 microns.

With the present arrangement, which, for example, for the planar film fuel cell 1 is applicable, a very small building possibility is given, the total thickness of in 1 shown arrangement is 200 to 500 microns.

4a and 4b show the possibility of being in 3 shown contact structure only on bars 10 the channel structure 11 or the webs 10 ' a corresponding open grid structure in 4b (for an open cathode structure). The passivation layer can be provided either only in the area around the individual contacts or in the entire channel or grid structure. If the passivation, for example by Oxi dation of the current collector basic body 6 made, this is done automatically on all non-precious metal existing individual contacts occupied areas. Alternatively, polymeric materials (eg, parylene) can be conformally deposited over the entire surface, or, for example, by spray coating with other polymers. Then holes are opened (by etching or laser) and then the individual contacts 8th galvanically deposited. If the individual contacts were produced first and then the polymer coating was carried out, an exposed contact on the contact surface is subsequently achieved by polishing the surface.

In a variant can the individual contacts according to the invention are "targeted" attached, it It is not a matter of adding particles to a polymer etc. is about the conductivity over a total area to increase. Instead, in this variant is deliberately a structured Breakdown of two materials with different property profiles intended. The contact structure according to the invention is in a second Vairante z. B. made by that on an electrically conductive body one with conductive Particles (gold or silver grains, Filled) Polymer applied and cured becomes. The shape and density of the particles is in this case, that always electrically conductive Paths from the conductive body to surface arise. This can be done during the curing by pressing one afterwards transported to be removed plate become. To the conductive Could make contacts subsequently a selective etching of the polymer z. B. with reactive ion etching. The contacts have to so not distributed evenly There is a medium distance.

Besides that is to say that the single contacts with high conductivity (also to keep the spreading resistance low) in a very small distance attached to each other. These are preferably around contacts, which are preferably smaller by an order of magnitude than For example, in measuring cells, in some areas, the conductivity can be determined with the help of protruding contacts. Besides, they are present in contrast to the individual contacts in measuring cells all contacts connected to the same electrically conductive body, So (apart from inhomogeneities the fuel cell) are all at the same potential.

5 and 6 show further examples of Stromableiterstrukturen, in which the individual contacts have an undercut.

If, for example, the contacts are produced galvanically in a resist structure, which is subsequently removed, a mushroom structure can be monitored by monitoring the resist 12 produce. This can advantageously entangle in the fabric or the fiber structure of the gas diffusion layer, so that there is a kind of Velcro effect and the low contact resistance is maintained even when completely releasing the contact force (see analogy to 2 ).

It can, as in 6 shown (see also 2 ) even longer individual contact structures can be produced, for example by electrodeposition in polymer membranes in which a microchannel structure was previously produced. Subsequently, these polymer membranes are then dissolved. The microchannel structure can be achieved by puncturing with fine needles or by bombardment with energetic particles. The resulting structures need not be completely symmetric or similar. Important are only a medium, uniform distribution and a preferred direction perpendicular to the substrate. The structures thus produced with diameters of a few micrometers, sometimes even less than 1 micrometer, would also be referred to as "nano-turf". At the same time, however, it is also possible to use carbon nanotubes (CNTs), which have been grown in a structured manner on the substrate before.

7 and 8th serve to represent the dimensions of the distances and diameters of the contacts. Because precious metals, such as gold, for the individual contacts 8th are to be used, is to be assumed by a very small, negligible contact resistance at these contacts. The greater resistance is due to the lateral current flow towards the contacts.

This resistance (spreading resistance, spreading resistance) depends on the distance and diameter of the contacts and the conductivity ρ of the layers, with thin layers also on the thickness of the layer. If the substrate (thus also the current collector base body) consists of metal (copper or aluminum or stainless steel), the spreading resistance can be neglected there compared to the spreading resistance in the electrode layer or gas diffusion layer of the membrane unit. The conductivity of steel is so high compared to the conductivity of the usual gas diffusion layers that presumably the conductivity of the gas diffusion layer is ultimately decisive for the spreading resistance. The spreading resistance accordingly 7 is calculated approximately according to the following formula R spread = 4ρ · d 2 / 3W 2 · [1 + d / (w - d)].

The greater the sheet resistance of the Stromableitergrundkörpers 6 or the gas diffusion layer or the electrode layer of the membrane unit, the smaller should be the distance between the individual contacts 8th be. The contact resistance here (see above) between 1 milliohm and 10 milliohms per square centimeter, the contact diameter of the single contact can be between 0.1 microns and 1000 microns. In an optimized system, the average distance between the individual contacts is so small that the spreading resistance in the electrode or gas diffusion layer is negligible.

In 8th you can see how the individual contacts 8th clearly above the surface E (see also 3 ) protrude the current collector structure, so that in the electrode or gas diffusion layer dreidimen sionaler electrical contact is formed, whereby the contact resistance is further reduced. In addition, the contact pressure of the current collector structure is distributed over a smaller total area of the contact cross sections. In this way, the total necessary for the minimum contact resistance contact pressure can be significantly reduced. This is another important advantage: the achievement of a uniform and sufficient contact pressure. Achieving low contact resistance is one of the most difficult constructive issues, especially with planar fuel cells, thereby finally providing a solution to this problem.

To produce the fuel cell arrangements according to the invention, in each case one current-carrying base body is provided with individual contacts distributed over a surface in a passivation layer 8th provided and then the individual contacts 8th in electrical connection with an electrode (anode 3 , Cathode 4 ) of the membrane unit 2 brought in, so that in 1 respectively. 2 structures are available. Details of these manufacturing processes have been discussed above in the individual embodiments.

Claims (25)

Fuel cell assembly ( 1 ) containing a membrane unit ( 2 ) with at least one electrode in the form of an anode ( 3 ) and / or a cathode ( 4 ), and at least one current collector structure ( 5 ), which an electrically conductive Stromableitergrundkörper ( 6 ), and the Stromableitergrundkörper ( 6 ) a passivation layer ( 7 ) with individual contacts distributed in a distributed manner ( 8th ), whereby the individual contacts ( 8th ) are arranged so that they on the one hand an electrode ( 3 . 4 ) and on the other hand the Stromableitergrundkörper ( 6 ) contact electrically. Fuel cell arrangement according to claim 1, characterized in that the individual contacts ( 8th ) Contact points ( 8a ) and the contact tips ( 8a ) of the individual contacts ( 8th ) to increase with the contact surface with the membrane unit ( 2 ) into an electrode and / or gas diffusion layer ( 9 ) of the membrane unit ( 2 ) is introduced frictionally and / or positively. Fuel cell arrangement according to claim 1 or 2, characterized in that the individual contacts ( 8th ) partially with the passivation layer ( 7 ) are coated. Fuel cell arrangement according to one of claims 2 or 3, characterized in that the contact tips ( 8a ) into the membrane unit ( 2 ) are inserted. Fuel cell arrangement according to one of claims 2 to 4, characterized in that the contact tips ( 8a ) the membrane unit ( 2 ) in some areas. Fuel cell arrangement according to one of the preceding claims, characterized in that the individual contacts ( 8th ) are made of precious metal or have a core body which is coated with precious metal. Fuel cell assembly according to claim 6, characterized characterized in that the precious metal is gold, silver or platinum. Fuel cell arrangement according to one of claims 6 or 7, characterized in that the core body of a metal, a electrically conductive Polymer or an electrically conductive ceramic, it being it is sufficient that the body made of polymer or ceramic with an outer conductive layer. Fuel cell arrangement according to one of the preceding claims, characterized in that the contact resistances of the individual contacts ( 8th ) between 1 milliohm and 10 milliohms per square centimeter. Fuel cell arrangement according to one of the preceding claims, characterized in that the individual contacts ( 8th ) have a diameter between 0.1 and 1000 microns, preferably between 1 microns and 100 microns, more preferably between 50 microns and 100 microns. Fuel cell arrangement according to one of claims 2 to 10, characterized in that the contact tips ( 8a ) protrude from the main surface plane between 100 microns and 1000 microns. Fuel cell arrangement according to one of the preceding claims, characterized in that the distance of the central axes of adjacent individual contacts ( 8th ) is between 10 microns and 1000 microns to each other. Fuel cell arrangement according to one of the preceding claims, characterized in that the thickness of the gas diffusion layer ( 9 ) is between 50 microns and 1000 microns. Fuel cell arrangement according to one of the preceding claims, characterized in that the gas diffusion layer ( 9 ) with the remaining membrane unit ( 2 ) is already mechanically connected. Fuel cell arrangement according to one of the preceding claims, characterized in that the current collector structure ( 5 ) Is part of a current collector plate or a bipolar plate. Fuel cell arrangement according to one of the preceding claims, characterized in that this fuel cell arrangement ( 1 ) is planar and has a total thickness between 100 microns and 1000 microns. Fuel cell stack containing at least one Fuel cell arrangement according to one of the preceding claims. Fuel cell assembly according to one of the preceding Claims, namely planar fuel cell assembly of very low height, the from a five-layer membrane unit exists with compressed gas diffusion layer and due to the mechanical / electrical Anchoring the current collector / channel structures with the five-layer membrane unit with only very small contact pressure can be mounted, and thus massive Pressure plates or end plates are dispensable. Fuel cell arrangement according to one of the preceding claims, characterized in that the current collector structure ( 5 ) to the electrode ( 3 . 4 ) additionally has a lattice-shaped structure, which is partially or selectively coated with noble metal for improved electrical conductivity. Method for producing a fuel cell arrangement ( 1 ), wherein at least one Stromableitergrundkörper ( 6 ) is provided with distributed in an insulating coating areal distributed individual contacts and then the individual contacts ( 8th ) in electrical connection with an electrode ( 3 ; 4 ) of the membrane unit ( 2 ) or diffusion layer ( 9 ) to be brought. Method according to claim 20, characterized in that the individual contacts ( 8th ) subsequently with a membrane unit ( 2 ) are pressed so that the contact tips ( 8a ) the individual contacts ( 8th ) frictionally and / or positively in the membrane unit ( 2 ) are anchored. Method according to claim 20, characterized in that the individual contacts ( 8th ) into the current collector base body ( 6 ) are inserted or plugged. A method according to claim 21, characterized in that the individual contacts ( 8th ) by coating, preferably elevations of the Stromableiterkörpers ( 6 ) arise. Method according to claim 20, characterized in that the individual contacts ( 8th ) grow in a resist pattern, which is subsequently removed. Method according to claim 20, characterized in that the individual contacts ( 8th ) by CVD or PVD processes.