DE102013223817A1 - Fuel cell element, fuel cell stack and method for producing a fuel cell or a fuel cell stack - Google Patents

Abstract

The present invention relates to a fuel cell element having at least two media distribution units and arranged between the two media distribution units membrane electrode assembly, wherein the membrane electrode unit unit at least partially a first sealing element and the two media distribution units each at least partially have a second sealing element, and wherein the first sealing element and the second sealing element contact at least in sections. Furthermore, the invention relates to a fuel cell stack comprising at least two membrane electrode units arranged in series with one another and media distribution units arranged between the two membrane electrode units and also delimiting them, as well as a method for producing the fuel cell element or the fuel cell stack.

Description

The present invention relates to a fuel cell element according to claim 1, a fuel cell stack according to claim 9 and a method according to claim 10 for producing the fuel cell element or the fuel cell stack, wherein the fuel cell consists of at least two media distribution units and arranged between the two media distribution units membrane electrode assembly and the membrane-electrode assembly comprises a first seal member and the media distribution unit comprises a second seal member.

STATE OF THE ART

Basically, it is known that a fuel cell, which is a galvanic cell that converts a chemical reaction energy of a continuously supplied fuel and an oxidant into electrical energy, consists of electrodes separated by a semipermeable membrane or an electrolyte. The electrode plates or also called bipolar plates, mainly comprise a metallic material and are coated with a catalyst such as a platinum material or a palladium material or other catalysts.

Bipolar plates are known to be made of two metal foils, wherein one or more (gas) distribution structures in the form of, for example, channels can be applied to the foil surfaces of the foils by means of an embossing process. After joining these two films together, corresponding cavities are created by these gas distributor structures through which a cooling medium can flow.

Advantageously, corresponding distributor structures are applied to both surfaces of the respective foils, that is to say on the front side (inner side) as well as on the rear side (outer side), so that the reaction gases can be passed through the distributor structure on the outside of the joined foils, for example. Hydrogen appears on the anode side as the reaction gas and air on the cathode side.

Alternatively, instead of the films with an embossed distribution structure on the surfaces of which two planar films with flat surfaces can be used. In this case, additional structural elements for conducting the media, that is for the conduction of gaseous and / or liquid media or fluids, are arranged between these two films and also on the two outer sides of the film.

An arrangement of a bipolar plate consisting of two foils therefore requires a seal of the bipolar plate on the one hand against the environment surrounding the bipolar plate and, on the other hand, also a seal within the bipolar plate between the individual structural elements or the distributor structures. By means of the use of such seals it should be made possible that the individual media, such as the anode gas, the cathode gas and / or the cooling medium, do not mix with one another or with one another. Furthermore, escape of one of these media to the outside into the outside environment is avoided.

These seals arranged on the individual foils or separator foils of the bipolar plate must always be injection-molded onto each individual foil prior to the assembly of the bipolar plate. This requires a time-consuming and cost-intensive spraying process, in which the arrangements of the individual foils to one another must be taken into account in such a way that an above-mentioned required sealing of the distributor structures can be ensured in an assembly of the foils to a bipolar plate.

DISCLOSURE OF THE INVENTION

It is therefore the object of the present invention to at least partially overcome the disadvantages described above. In particular, it is the object of the present invention to provide a fuel cell element, a fuel cell stack and a method for producing a fuel cell element or a fuel cell stack, by which in a simple and cost-effective manner, a reliable sealing of the distributor structures against the outside environment and also with each other in terms of avoidance of media blending is made possible.

The above object is achieved by a fuel cell element with the features of claim 1, by a fuel cell stack with the features of claim 9 and by a method for producing the fuel cell element or the fuel cell stack having the features of claim 10. Further features and details of the invention will become apparent the dependent claims, the description and the drawings. In this case, features and details that are described in connection with the fuel cell element or the fuel cell stack, of course, also in connection with the method according to the invention and in each case vice versa, so that with respect to the disclosure of the individual aspects of the invention always reciprocal reference is or may be.

The fuel cell element according to the invention has at least two media distribution units and a membrane electrode unit arranged between the two media distribution units, wherein the membrane electrode unit at least partially a first sealing element and the two media distribution units at least partially have a second sealing element. In the context of the present invention, the first sealing element and the second sealing element contact each other at least in sections.

The membrane-electrode assembly (MEA) forms an essential part of a fuel cell element and has at least a cathode element and an anode element and an electrolyte membrane element arranged between the cathode element and the anode element. Preferably, the membrane-electrode assembly is plate-shaped and thus has two parallel reaction surfaces and these reaction surfaces connecting lateral surfaces. It is therefore conceivable that the membrane-electrode unit is designed in the form of a cuboid, in particular in the form of a plate or a cylinder, in particular in the form of a disk.

The media distribution unit according to the present invention forms the area adjacent the membrane-electrode assembly through which the media, such as the cathode gas, the anode gas, and / or the coolant, are toward and away from the membrane-electrode assembly or can be transported along the membrane-electrode assembly along.

Preferably, the first sealing element and the second sealing element together form a contact seal in which the two sealing elements touch each other. In the context of the invention, the first sealing element may comprise a soft, flexible, elastic or deformable material. The first sealing element preferably consists at least partially of a rubber-like elastomer or plastic material and consequently represents a soft-material seal. The first sealing element may include, inter alia, a material or a material from the following group: nitrile-butadiene rubber, fluorocarbon Rubber, ethylene-propylene-diene rubber, acrylate rubber, methyl-vinyl-silicone rubber, polyethane, poly-tetra-fluoro-ethylene, or a comparable material. The modulus of elasticity of the first sealing element can be, for example, between 0.001-0.7 GPa and more preferably between 0.01-0.06 GPa.

In contrast, the second sealing element, which is arranged in areas of the media distribution units, a stiffer, harder, more rigid, inelastic material than the first sealing element of the membrane-electrode assembly. Preferably, the second sealing element comprises a plastic material, such as polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyethylene terephthalate or a similar or comparable material. Thus, it is conceivable that the second sealing element has a larger or higher than the first sealing element elastic modulus of preferably 0.7-7 GPa and more preferably of 1.5-5 GPa.

Advantageously, with the sealing concept described above, that is, due to a combination of differing elastic sealing materials, a functionally reliable seal and a cost-effective production of the seal of the parts to be joined and consequently also a cost-effective production of the parts themselves are made possible. By means of in particular a first soft sealing element and a second relatively hard sealing element, a simple construction of a fuel cell element made of only two prefabricated components is advantageously made possible.

In the context of the invention, it is conceivable that the media distribution unit has at least two and preferably three media distribution structure regions, which are each arranged at a distance from one another by means of a separator film arranged at least in sections between the two media distribution structure regions. A media distribution structure area is in particular a three-dimensionally structured, porous area through which the fuel cell media, such as the anode gas, the cathode gas and / or the coolant, can flow or flow for cooling the fuel cell or the fuel cell element. Advantageously, the separator sheets and the media distribution pattern portions are stacked on top of each other in the form of a sandwich construction. It is also conceivable that the Separatorfolien and the media distribution structure areas are materially connected to each other in particular during a previous manufacturing process, which can be used as a joining process, for example, a sintering or soldering. Advantageously, according to the present invention, an arrangement of the separator sheets with the media distribution pattern areas in the sandwich construction without the use of embossed or laser welded components. Starting from a media distribution unit with three media distribution structure areas, advantageously one of the three media distribution structure areas serves to distribute the anode gas, another one of the three media distribution structure areas to distribute the cathode gas, and a third of the three Media distribution structure areas for distribution of the cooling medium, which may be present in a liquid or even a gaseous state. Starting from a media distribution unit having two media distribution structure areas, wherein this media distribution unit is arranged in particular in an end area of a fuel cell element or a fuel cell stack, one of the two media distribution structure areas serves for distributing an anode gas or a cathode gas, depending on the arrangement on the membrane electrode unit, and another of the two media distribution structure areas serves to distribute the cooling medium.

It is furthermore conceivable that the media distribution structure regions comprise or consist at least in sections of metallic fabric structures and / or an expanded metal and / or a metal foam.

In the context of the invention, it is possible for at least one of the two separator foils to have an applied distributor structure, which extends in particular along one or else along both flow surfaces. Here, the flow surface is understood to mean the surface along which a medium of the fuel cell or of the fuel cell element can flow or flow. In this case, the distributor structure can be designed, for example, in the form of a channel or a depression which runs meander-shaped, zigzag-shaped or wave-shaped or in another form along the flow surface.

It is furthermore possible for the first sealing element to surround at least regions of individual boundary surfaces of the membrane-electrode unit, wherein at least one of the boundary surfaces is connected to at least one energy transmission conductor. In this case, in particular the reaction surface or surfaces as well as the lateral surfaces are referred to as delimiting surfaces. The lateral surfaces or lateral surface areas bound the membrane-electrode unit as a complete unit in its dimension. In a cuboid or plate-like configuration of the membrane-electrode assembly, the membrane-electrode assembly has a total of two reaction surfaces and four lateral surfaces, which extend from a first reaction surface to a second reaction surface. In a cylindrical and in particular disc-shaped configuration of the membrane-electrode assembly, the membrane-electrode assembly has two reaction surfaces and a lateral surface which extends from a first reaction surface to a second reaction surface. In this case, the reaction surfaces are those surfaces which are in operative connection with the outside environment and consequently allow, in particular, reaction gases, such as hydrogen or air, to react on the surface thereof. Notably, the first sealing element extends almost completely along the lateral surface or the lateral surfaces and at least partially along the reaction surfaces, in particular along those regions of the reaction surfaces which adjoin the lateral surfaces. As a result, the first sealing element is formed as a circumferential seal, which completely surrounds the membrane-electrode assembly, especially in its edge region.

In the context of the invention, it is conceivable for the second sealing element to surround at least regions of individual boundary surfaces of the separator foils of the media distributor unit. The boundary surfaces of the separator sheets according to the present invention are flow surfaces and shell surfaces. The lateral surfaces extend between the two flow surfaces, which in turn are at least partially in contact with one of the media. Accordingly, the flow surface is understood to mean a surface along which a medium of the fuel cell unit, such as the anode gas, the cathode gas and / or the cooling medium, flows or flows. In the case of a cuboidal or plate-like configuration of the separator film, the separator film has a total of two flow surfaces and four lateral surfaces which extend from a first flow surface to a second flow surface. In the case of a cylindrical and, in particular, disc-shaped configuration of the separator film, the separator film has two flow surfaces and a lateral surface, which extends from a first flow surface to a second flow surface.

It is preferably conceivable for both separator foils to be arranged in a common second sealing element, wherein the second sealing element surrounds at least the lateral surface or the lateral surfaces of the separator foils primarily completely, but at least partially, and extends to areas of the flow surfaces of the separator foils adjacent to the lateral surface extends.

In particular, the second sealing element advantageously serves for sealing the cooling medium relative to the outside environment, as well as for mechanically fixing or locking the first sealing element to the membrane-electrode unit and within the fuel cell element and / or for enabling a mechanical stability of a fuel cell element as well as a fuel cell stack.

It is possible according to the invention that the second sealing element of the first Media distribution unit contacted the second sealing element of the second media distribution unit at least in sections. Here, after pressing or pressing together or compressing the membrane-electrode assembly with the media distribution units, the first seal is advantageously almost completely surrounded by the respective second seals of the media distribution units, so that the second seals of the media distribution units touch each other, at least in individual areas. Advantageously, the first seal is thus dimensioned such that it is in the assembled state of the membrane-electrode assembly and the media distribution units, which is also referred to herein as a fuel cell element and briefly as a cell element, within the cell element without contact with the outside environment and thus completely from the respective second Surround sealing elements, arranged and designed.

Optionally, it is conceivable that at least a portion of the first sealing element is arranged at least in sections between the second sealing element of the first media distributor unit and the second sealing element of the second media distributor unit.

Furthermore, a fuel cell stack comprising at least two membrane-electrode units arranged in series with one another and media distribution units arranged between the two membrane-electrode units and / or arranged in a limiting manner is claimed. According to the invention, the membrane-electrode assemblies each comprise, at least in sections, a first sealing element and the media distributor units at least in sections a second sealing element, the first sealing element and the second sealing element contacting each other at least in sections.

Accordingly, it is also conceivable that the fuel cell stack according to the invention has more than two membrane-electrode units, between each of which a media distributor unit with primarily three media distributor structure regions or media distributor structures is arranged. In the context of the invention, the media distribution units, which form the end of the fuel cell stack, and consequently are arranged only on a membrane-electrode unit in order to limit them to the environment, preferably have two media distribution structure regions. Here, one of the two media distribution structure areas serves to distribute or direct a gaseous medium, such as the electrode gas of the respective electrode and the other of the two media distribution structure areas for distributing or guiding a cooling medium, such as a liquid medium.

In the described fuel cell stack, all the advantages that have already been described for the fuel cell element result.

• – Anspritzen des ersten Dichtungselementes zumindest in Bereiche einzelner Begrenzungsflächen der Membran-Elektroden-Einheit,
• – Anspritzen des zweiten Dichtungselementes zumindest in Bereiche einzelner Begrenzungsflächen der Separatorfolien der Medienverteilereinheit,
• – Anordnen zumindest einer Membran-Elektroden-Einheit zwischen jeweils zwei Medienverteilereinheiten, und
• – Aneinanderpressen der Membran-Elektroden Einheit mit den Medienverteilereinheiten bis das zweite Dichtungselement der ersten Medienverteilereinheit zumindest abschnittweise das zweite Dichtungselement der zweiten Medienverteilereinheit kontaktiert, oder bis das zweite Dichtungselement der ersten Medienverteilereinheit sowie das zweite Dichtungselement der zweiten Medienverteilereinheit jeweils wenigstens einen Bereich des zumindest teilweise zwischen die jeweilig zueinander angeordneten zweiten Dichtungselemente der Medienverteilereinheiten anordenbaren ersten Dichtungselementes der Membran-Elektroden-Einheit kontaktieren

Furthermore, a method of manufacturing a fuel cell element or a fuel cell stack as described above is claimed. The method according to the invention comprises at least the following steps:

• - Injection of the first sealing element at least in areas of individual boundary surfaces of the membrane electrode assembly,
• Injection molding of the second sealing element at least in areas of individual boundary surfaces of the separator foils of the media distribution unit,
• Arranging at least one membrane-electrode unit between in each case two media distribution units, and
• Pressing the membrane electrode assembly together with the media distribution units until the second sealing element of the first media distribution unit at least partially contacts the second sealing element of the second media distribution unit, or until the second sealing element of the first media distribution unit and the second sealing element of the second media distribution unit each at least partially interpose at least a portion of the respective arranged second sealing elements of the media distribution units can be arranged to contact the first sealing element of the membrane-electrode unit

According to the method according to the invention, the first sealing element, which consists primarily of an elastic or soft rubber-like material, or has this molded onto an edge region of the membrane-electrode unit. In particular, the membrane-electrode unit has a flat, plate-like or disk-like overall structure, which consequently comprises a reaction surface and a lateral surface. The first sealing element is advantageously a sealing layer, which is injection-molded in particular in the area of the circumferential surface or enveloping the membrane-electrode unit. It is advantageously possible for the sealing layer or the sealing element also to be injection-molded in regions of the reaction surface and in particular in the edge regions of the reaction surface (s) which adjoin the lateral surface or merge into it. Consequently, in a first method step, a first element with a seal, that is to say the membrane-electrode unit with a molded-on first sealing element, is manufactured or manufactured.

In a further production step, the media distribution unit is then manufactured with a seal. For this purpose, it is encapsulated in a manner comparable to the membrane-electrode unit, with a rigid or rigid plastic material, in particular in the edge area. The media distribution unit also has primarily a flat plate-shaped or disc-shaped overall structure, the edge regions of the separator films protruding at least in sections with respect to the media distribution structure units. Accordingly, the plastic material is sprayed onto the marginal areas of the separator foils and in this case in particular around the lateral area and in particular also around areas of the flow areas. It is therefore conceivable that both Separatorfolien be encapsulated with one and the same sealing element or sealing material and thus connected by it. This creates a second element or component, namely the media distribution unit with a molded second sealing element.

Both components are arranged on one another in a subsequent third method step such that the first sealing element is at least partially introduced into areas of the media distribution unit and consequently arranged at least in sections between a media distributor structure area and the second sealing element within a sealing groove. If a further media distributor unit with molded sealing element is arranged on the first media distributor unit with molded sealing element, it is conceivable for at least areas of the respective second sealing elements of the two media distributor units to touch, if the shaping of the first sealing element makes this possible. This means that, if the first sealing element has a predominantly cubic shape, which can be completely surrounded by the second sealing elements of the media distribution units, these second sealing elements at least partially contact each other. However, it is also conceivable that the respective second sealing elements of the media distribution units only contact sections at least after a compression of the now present three components.

It is also conceivable according to the present invention that the respective second sealing elements do not contact at all, not even after pressing together the at least three components, namely the two media distribution units and the membrane electrode unit arranged between the media distribution units. In this case, the first sealing element is designed or dimensioned, in particular larger than in the previous case, when the respective second sealing elements could touch, that when the three components are pressed together, it is pressed at least in sections between the media distribution units or their second sealing elements is pressed. Consequently, the first sealing element lies at least partially between the second sealing elements. However, it is also conceivable that, alternatively or in addition to the above-mentioned modified size, the first sealing element of the membrane-electrode assembly also has a modified shape with, in particular, a projection region which, when the three components are arranged one another, advantageously directly between the second sealing elements of the media distribution units namely, the second sealing element of the first media distributor unit and the second sealing element of the second media distributor unit. Accordingly, in particular after pressing or pressing together of the three components, this projection region of the first sealing element of the membrane-electrode unit is pressed in between the two second sealing elements of the media distribution units, so that the respective second sealing elements of the media distribution units can not contact each other even after the pressing.

After arranging or compressing the individual components with one another, it is conceivable that the resulting fuel cell element is limited with end plates or end elements, which at least partially surround the fuel cell element and hold together.

In the described method, all the advantages that have already been described for the fuel cell element and / or the fuel cell stack result.

PREFERRED EMBODIMENTS

The fuel cell element according to the invention and the fuel cell stack according to the invention are explained in more detail below with reference to drawings. Each show schematically:

1 a side view of an embodiment of a membrane-electrode assembly according to the invention with a first sealing element in a sectional view,

2 a side view of an embodiment of a media distribution unit according to the invention with a second sealing element in a sectional view,

3 a side view of a first embodiment of a fuel cell element according to the invention in a sectional view,

4 a side view of a second embodiment of a fuel cell element according to the invention in a sectional view,

5 a side view of a first embodiment of a fuel cell stack according to the invention in a sectional view,

6 a side view of a second embodiment of a fuel cell stack according to the invention in a sectional view,

7 a plan view of an embodiment of a fuel cell element,

8th a plan view of a sectional view of the in 7 shown section A,

9 a representation of in the 8th shown section AA,

10 , a representation of in the 8th shown section BB,

11 a representation of in the 8th shown section CC, and

12 a representation of in the 8th shown section DD. Elements with the same function and mode of action are in the 1 to 12 each provided with the same reference numerals.

In 1 is a schematic side view of an embodiment of a membrane electrode assembly according to the invention 1 with a first sealing element 2 shown in section. The membrane-electrode unit 1 is designed plate-shaped or disc-shaped and has a reaction surface 30 or a reaction surface and a lateral surface 31 on. The lateral surface 31 can in a disk-shaped membrane electrode assembly 1 be circumferential. In contrast, has a plate-shaped membrane electrode assembly 1 , In particular, if this consists of a quadrangular plate, a total of four lateral surfaces 31 on. However, it is also conceivable that the membrane-electrode assembly more than four corners or edges and consequently more than four lateral surfaces 31 having. The schematically illustrated membrane-electrode unit 1 consists mainly of two electrodes and an electrolyte membrane arranged between these electrodes. It is also conceivable that the membrane electrode unit 1 Furthermore, a gas diffusion layer or two gas diffusion layers (not shown here), which favor the chemical reaction of a fuel cell or a fuel cell element. In the edge area of the membrane-electrode unit 1 and in particular in the area of the lateral surface (s) 31 , which is a boundary surface, is a seal 2 arranged and mainly molded, which is the membrane-electrode unit 1 encased in this edge region at least partially. The sealing element 2 envelops the membrane-electrode unit mainly also to areas of the reaction surfaces 30 , and in particular down to areas of the reaction surfaces 30 , which on the lateral surface (s) 31 adjoin. Like in the 1 shown, the first sealing element 2 , which advantageously consists of an elastic or soft or flexible rubber-like or rubber-like material or has at least one such material, a U-shaped cross-sectional area to surround at least one edge region of the membrane-electrode assembly or areas of the boundary surfaces or to coat.

In the 2 is a side view of an embodiment of a media distribution unit according to the invention 10 with a second sealing element 13 shown in section. According to the 2 consists of the media distribution unit 10 from two separator foils 11 and 12 , which can also be referred to as Separatorplatten. The two separator foils 11 and 12 are by means of a media distribution structure or a media distribution structure area 15 spaced apart. This second media distribution structure area 15 primarily serves for distributing and / or conducting a cooling medium and preferably a liquid cooling medium. In addition, the media distributor unit has 10 two more media distribution structure areas 14 and 16 which are designed primarily as gas distributor structures to the electrode gas of each adjacent membrane electrode assemblies 1 (please refer 1 ) to distribute or direct. However, it is also conceivable that the media distribution unit 10 only two media distribution structure areas 14 and 15 respectively. 15 and 16 and thus from an electrode gas media manifold structure area 14 or 16 and a cooling medium distribution structure region 15 consists. Such a media distribution unit 10 is especially as a final element within a fuel cell stack 110 (see. 5 and 6 ), if therefore only one membrane electrode assembly 1 at the media distribution unit 10 is arranged adjacent. Consequently, the media distributor unit has 10 a single fuel cell element 100 (see. 3 and 4 ) with only a single membrane-electrode unit 1 also only two media distribution structure areas 14 and 15 respectively. 15 and 16 on, since the media distribution unit 10 only one electrode gas of a single electrode (cathode or anode) of a single membrane electrode assembly 1 distribute or direct.

Like in the 2 shown, surrounds or surrounds the second sealing element 13 the edge areas of both Separatorfolien 11 . 12 so that both separator foils 11 . 12 in a common second sealing element 13 are arranged. As border areas or boundary surfaces of the separator foils 11 . 12 , which may be plate-shaped or disc-shaped, in particular the lateral surface (s) 41 respectively. 51 Understood. Accordingly, in the case of a disk-shaped configuration of the separator films 11 respectively. 12 every separator foil 11 respectively. 12 only a lateral surface 41 respectively. 51 exhibit. While in a square or four-edged plate-like configuration of Separatorfolien 11 respectively. 12 every separator foil 11 respectively. 12 a total of four lateral surfaces 41 respectively. 51 having. It is also conceivable that the Separatorfolien 11 respectively. 12 each have more than four corners or edges, so consequently also the number of lateral surfaces 41 respectively. 51 increased in relation to the number of edges. The second sealing element 13 Accordingly, at least partially and advantageously completely surrounds the lateral surface (s) 41 respectively. 51 and preferably also areas of the two flow surfaces 40 respectively. 50 , which are also assigned to the boundary surfaces and each of which Separatorfolie 11 respectively. 12 has two surfaces. At the flow surfaces 40 . 50 the media to be distributed or guided can be guided along. Advantageously, both flow surfaces 40 . 50 every separator foil 11 . 12 Contours, such as depressions, grooves, recesses (not shown here) in order to guide the along-flowing media targeted and pointing the way along the surface. The separator films are advantageous 11 respectively. 12 aligned or arranged parallel to each other.

The media distribution structure areas 14 . 15 and 16 have, for example, metallic fabric structures or an expanded metal or even metal foam in order to be able to advantageously ensure distribution and / or conduction of the individual media. It is also conceivable that the first 14 and third media distribution structure area 16 , Which each serve to distribute the electrode gases, in the length and / or width are dimensioned smaller than the second media structure area 15 , which serves for distributing the cooling medium. This advantageously serves to arrange a membrane-electrode unit 1 with molded-on first sealing element 2 in this remaining space or area, which can also be referred to as a sealing groove B to order to order a fuel cell element according to the invention 100 to be able to realize.

In the 3 is a schematic side view of a first embodiment of a fuel cell element according to the invention 100 shown in sectional view, wherein the fuel cell element 10 from a membrane-electrode unit 1 with molded-on first sealing element 2 and two media distribution units 10a and 10b each with molded second sealing element 13a and 13b consists.

The first media distribution unit 10a has two separator sheets 11a and 12a as well as two media distribution structure areas 15a and 16a on while the second media distribution unit 10b also two separator foils 11b and 12b and a first media distribution structure area 14b and a second media distribution structure area 15b having. The media distribution structure areas 15a and 15b advantageously serve to conduct a cooling medium while the media distribution structure areas 14b and 16a for conducting the cathode or the anode gas of the membrane-electrode assembly 1 serve.

The two media distribution units 10a and 10b are so on the membrane-electrode assembly 1 arranged that the flow surfaces 40 . 50 (see. 2 ) of the separator foils 11 . 12a . 11b . 12b essentially parallel to the reaction surfaces 30 the membrane-electrode unit 1 extend. Become the media distribution units 10a and 10b with the membrane electrode assembly arranged between them 1 Pressed, then the first sealing element 2 in an interior area between the two media distribution devices 10a . 10b received and by individual areas of the respective second sealing elements 13a . 13b contacted and preferably completely surrounded. Advantageously, the first sealing element contacts 2 every second sealing element 13a . 13b as well as two media distribution structure areas 16a and 14b to be able to deliver the electrode gas to this.

According to the in 3 In the embodiment shown, the two second sealing elements contact or contact each other 13a and 13b in a circulation area 60 ,

Consequently, the first sealing element advantageously seals 2 the media distribution structure areas 16a and 14b to prevent uncontrolled leakage of the electrode gases, while the respective second sealing elements 13a and 13b serve to slipping out of the first sealing element 2 to avoid this and thus mechanically within the fuel cell element 100 to fix. This advantageously also serves to ensure the mechanical stability of the fuel cell element 100 and consequently also the fuel cell stack 110 (see. 5 and 6 ). Furthermore, each of the second seal members serves 13a and 13b to a leakage of the cooling medium from the second Media distribution structure area 15a . 15b to avoid and thus does not serve as a limiting element and stabilizing element, but also as a sealing element with respect to the second media distribution structure area 15a . 15b ,

The second sealing elements 13a . 13b advantageously also serve a defined distance between the media distribution units 10a . 10b to allow for arranging the membrane-electrode unit 1 between them realize. Furthermore, it can be advantageously ensured, in particular on account of the first sealing element, that a force flow predominantly via the sealing elements 2 . 13a and or 13b runs. In addition, advantageously low contact and contact resistances can be realized within the fuel cell element.

4 schematically shows a side view of a second embodiment of a fuel cell element according to the invention 100 in section. This second embodiment differs from that in the 3 shown substantially only in that at least during or after an assembly of the three components, namely the two media distribution units 10a and 10b and one between these two media distribution units 10a . 10b arranged membrane electrode assembly 1 , the second sealing elements 13a and 13b the media distribution units 10a . 10b do not touch each other or at least partially not contact. Rather, the first sealing element 2 during the pressing process between the two second sealing elements 13a and 13b pressed. This is the first sealing element 2 advantageous in the scope or in its volume or its width dimensioned larger than, for example, the first sealing element 2 the first embodiment according to the 3 , However, it is also conceivable that also due to the dimension of the first sealing element 2 the second sealing elements 13a . 13b after the pressing process do not contact each other and the first sealing element 2 but not between the two second sealing elements 13a . 13b is guided. In this case, there would be a gap between the two second sealing elements 13a . 13b remain. It is also conceivable that the first sealing element 2 a mold advantageously having a projecting portion, which before and / or after the pressing operation between the second sealing elements 13a and 13b Arrange so that these second sealing elements 13a and 13b can not touch or contact each other.

In the 5 is a schematic side view of a first embodiment of a fuel cell stack according to the invention 110 shown in section. This fuel cell stack consists of a plurality of membrane electrode assemblies 1a - 1n + 1 each with first sealing elements 2a - 2n + 1 , as well as from a variety of media distribution units 10a - 10n + 2 each with second sealing elements 13a - 13n + 2 and from a variety of media distribution fabric areas 14a - 14n + 2 . 15a - 15n + 2 . 16a - 16n + 2 , The membrane-electrode units 1a - 1n + 1 and the media distribution units 10a - 10n + 2 are alternately stacked in sandwich construction, with the second sealing elements 13a - 13n + 2 at least partially contact each other at least after the compression of the components. Consequently, the in 5 illustrated fuel cell stack 110 essentially with the one in the 3 to compare shown embodiment in which the second sealing elements 13a . 13b touch and the first sealing element 2 from the second sealing elements 13a . 13b at least partially and preferably fully enclosed (cf. 3 ). Advantageously, the first media distribution unit 10a and the last media distribution unit 10n + 2 in the fuel cell stack 110 no first media distribution structure area 14a or no third media distribution structure area 16n + 2 on how this particular in the 6 is shown.

In the 6 is a schematic side view of a second embodiment of a fuel cell stack according to the invention 110 shown in section, which differs from that in the 5 illustrated embodiment only differs in that the individual components pressed together, such as the membrane electrode assemblies 1a - 1n + 1 with respective first sealing element 2a - 2n + 1 and the media distribution units 10a - 10n + 2 with respective second sealing element 13a - 13n + 2 , are alternately arranged in sandwich construction after the pressing process such that at least portions of the first sealing element 2a - 2n + 1 between sections of the respective second sealing elements arranged relative to one another 13a - 13n + 2 arranged and / or at least pressed or were due to the pressing process. Consequently, the one in the 6 shown fuel cell stack 110 essentially with the one in the 4 to compare the embodiment shown so that further here on the comments on 4 Reference is made.

Advantageously, the first sealing element 2a - 2n + 1 and the second sealing element 13a - 13n + 2 by means of an injection molding process to the membrane-electrode assembly 1a - 1n + 1 or the media distribution unit 10a - 10n + 1 appropriate. The region B or the sealing groove B (cf. 2 ) serves at least during the injection molding process for tool holder, that is, for receiving the injection molding tool, whereby a Damage to the individual media distribution structure areas 14a - 14n + 2 . 15a - 15n + 2 . 16a - 16n + 2 is prevented.

The 7 schematically shows a plan view of an embodiment of a media distribution unit 10 or a fuel cell element 100 comprising two media distribution units and a membrane electrode assembly disposed therebetween 2 , especially in the 3 and 4 shown. The fuel cell element 100 preferably has port areas 20 - 25 through which gaseous or liquid media can enter or exit. Accordingly, the port area is used 20 to supply a required for the reaction at the anode medium, such as hydrogen, and the resulting at the anode after the reaction anode gas over the port region 21 or the media port 21 dissipate again. Accordingly, the cathode region also has a port region 22 on which, for example, oxygen is supplied, and your port area 23 over which the resulting water is removed. Furthermore, the fuel cell element 100 a port area 24 for supplying a coolant for cooling the fuel cell element 100 as well as a port area 25 for the discharge of this coolant.

In the 8th is a schematic plan view of a sectional view of the in 7 shown section A, shown in the 7 shown fuel cell element 100 in particular in the area of the membrane-electrode unit 1 and substantially along the reaction surface 30 (see. 1 ) was cut. Like in the 8th can be seen, the first sealing element 2 at least partially from the second sealing element 13 limited to the environment U or delimited to advantageously a locking or stabilization of the first sealing element 2 within the fuel cell element 100 to be able to guarantee. The in the 8th at least partially port areas shown 22 and 24 are also advantageous with the first sealing element 2 and hence the second sealing element 13 at least partially demarcated to the environment and thus form at least one part of the membrane electrode assembly 1 and / or the media distribution unit 10 (see. 1 . 3 . 4 ).

9 schematically shows a representation of the in the 8th shown section AA. The membrane-electrode unit 1 is in particular in its edge region with the first sealing element 2 encased, which in turn at least with a region in a sealing groove B, which between the second sealing element 13 and the first media distribution structure area 14 consists, engages, so advantageously a locking of the membrane electrode assembly 1 within the fuel cell element 100 can be ensured. A region of the first sealing element 2 also extends in the viewing plane horizontally along the illustrated second sealing element 13 so that in the 9 shown arrangement substantially in 4 shown embodiment of a fuel cell element 100 corresponds and therefore to the 4 described embodiments reference is made.

Due to the structure and the manufacturing process or the injection molding process, in which, among other things, the second sealing element 13 to the media distribution unit 10 is injected, penetrates the material of the second sealing element 13 at least slightly into an area of the second media distribution structure area 15 a, as with the reference numeral 70 shown. Such a material entry 70 However, it is not relevant to the function, as a result of the function of the fuel cell element 100 is not affected.

In the 10 is a schematic representation of the in the 8th shown section BB, in particular it is illustrated that the material entry 70 along the entire width of the second media distribution structure area 15 can extend. The further shows the 10 also the sealing groove B for introducing at least a portion of the first sealing element 2 , Consequently, it becomes clear that, in particular, the first 14 and the third media distribution structure area 16 (see. 9 ) each have a smaller or smaller dimensions in its length or width, but not in its thickness than the second media distribution structure area 15 (see. 9 ), which advantageously the second sealing element 13 contacted at least in sections. Advantageously, the media distribution structures 14 . 15 and 16 each have a substantially identical thickness, wherein their configuration with respect to the distribution structure and the materials used therefor, etc. may be different.

In the 11 is a schematic representation of the in the 8th shown section CC and in the 12 is a schematic representation of the in the 8th shown section DD shown. It becomes clear that the first sealing element 2 at least a portion of a flow surface of the first separator film 11 contacted in the region of the sealing groove B, in which the first media distribution structure area 14 is arranged. Further show 11 and 12 the arrangement of both Separatorfolien 11 . 12 within a common second sealing element 13 through which both separator sheets 11 . 12 not only spaced from each other, but are also secured against slipping or shifting. Furthermore, it becomes clear that in particular the second media distribution structure area 15 such by means of the second sealing element 13 is sealed, that prevents inadvertent leakage of the cooling medium and a targeted entry or exit of the cooling medium over the port areas 24 and 15 (see. 7 ).

Claims (10)

Fuel cell element ( 100 ) comprising at least two media distribution units ( 10 . 10a - 10n + 2 ) and one between the two media distribution units ( 10 . 10a - 10n + 2 ) arranged membrane electrode unit ( 1 . 1a - 1n + 1 ), wherein the membrane-electrode unit ( 1 . 1a - 1n + 1 ) at least partially a first sealing element ( 2 . 2a - 2n + 1 ) and the two media distribution units ( 10 . 10a - 10n + 2 ) each at least partially a second sealing element ( 13 . 13a - 13n + 2 ), and wherein the first sealing element ( 2 . 2a - 2n + 1 ) and the second sealing element ( 13 . 13a - 13n + 2 ) Contact at least in sections. Fuel cell element ( 100 ) according to claim 1, characterized in that the media distribution unit ( 10 . 10a - 10n + 2 ) at least two and preferably three media distribution structure areas ( 14 . 14a - 14n + 2 . 15 . 15a - 15n + 2 . 16 . 16a - 16n + 2 ), which in each case by means of at least partially between the two media distribution structure areas ( 14 . 14a - 14n + 2 . 15 . 15a - 15n + 2 . 16 . 16a - 16n + 2 ) arranged Separatorfolien ( 11 . 11a - 11n + 2 . 12 . 12a - 12n + 2 ) are spaced from each other. Fuel cell element ( 100 ) according to one of the preceding claims, characterized in that the media distribution structure areas ( 14 . 14a - 14n + 2 . 15 . 15a - 15n + 2 . 16 . 16a - 16n + 2 ) at least partially have metallic tissue structures and / or an expanded metal and / or a metal foam. Fuel cell element ( 100 ) according to one of the preceding claims, characterized in that at least one of the separator foils ( 11 . 11a - 11n + 2 . 12 . 12a - 12n + 2 ) has an applied distribution structure. Fuel cell element ( 100 ) according to one of the preceding claims, characterized in that the first sealing element ( 2 . 2a - 2n + 1 ) at least regions of individual boundary surfaces of the membrane-electrode assembly ( 1 . 1a - 1n + 1 ), wherein at least one of the boundary surfaces is connected to at least one energy transfer conductor. Fuel cell element ( 100 ) according to one of the preceding claims, characterized in that the second sealing element ( 13 . 13a - 13n + 2 ) at least regions of individual boundary surfaces of the separator foils 11 . 11a - 11n + 2 . 12 . 12a - 12n + 2 ) of the media distribution unit ( 10 . 10a - 10n + 2 ) surrounds. Fuel cell element ( 100 ) according to one of the preceding claims, characterized in that the second sealing element ( 13 . 13a - 13n + 2 ) of the first media distribution unit ( 10 . 10a - 10n + 2 ) the second sealing element ( 13 . 13a - 13n + 2 ) of the second media distribution unit ( 10 . 10a - 10n + 2 ) contacted at least in sections. Fuel cell element ( 100 ) according to one of the preceding claims 1 to 7, characterized in that between the second sealing element ( 13 . 13a - 13n + 2 ) of the first media distribution unit ( 10 . 10a - 10n + 2 ) and the second sealing element ( 13 . 13a - 13n + 2 ) of the second media distribution unit ( 10 . 10a - 10n + 2 ) at least partially at least a portion of the first sealing element ( 2 . 2a - 2n + 1 ) is arranged. Fuel cell stack ( 110 ), comprising at least two membrane-electrode units arranged in series with one another ( 1 . 1a - 1n + 1 ) and between the two membrane electrode assemblies ( 1 . 1a - 1n + 1 ) arranged as well as these limiting arranged media distribution units ( 10 . 10a - 10n + 2 ), wherein the membrane-electrode units ( 1 . 1a - 1n + 1 ) each at least partially a first sealing element ( 2 . 2a - 2n + 1 ) and the media distribution units ( 10 . 10a - 10n + 2 ) each at least partially a second sealing element ( 13 . 13a - 13n + 2 ), and wherein the first sealing element ( 2 . 2a - 2n + 1 ) and the second sealing element ( 13 . 13a - 13n + 2 ) contact each other at least in sections ... Method for producing a fuel cell element ( 100 ) according to one of the preceding claims 1 to 8 or a fuel cell stack ( 110 ) according to the preceding claim 9, comprising at least the steps: - injection molding of the first sealing element ( 2 . 2a - 2n + 1 ) at least in areas of individual boundary surfaces of the membrane-electrode assembly ( 1 . 1a - 1n + 1 ), - injection molding of the second sealing element ( 13 . 13a - 13n + 2 ) at least in areas of individual boundary surfaces of Separatorfolien ( 11 . 11a - 11n + 2 . 12 . 12a - 12n + 2 ) of the media distribution unit ( 10 . 10a - 10n + 2 ), - arranging at least one membrane-electrode unit ( 1 . 1a - 1n + 1 ) between two media distribution units ( 10 . 10a - 10n + 2 ), and Pressing the membrane-electrode assembly together ( 1 . 1a - 1n + 1 ), with the media distribution units ( 10 . 10a - 10n + 2 ) until the second sealing element ( 13 . 13a - 13n + 2 ) of the first media distribution unit ( 10 . 10a - 10n + 2 ) at least in sections, the second sealing element ( 13 . 13a - 13n + 2 ) of the second media distribution unit ( 10 . 10a - 10n + 2 ) or until the second sealing element ( 13 . 13a - 13n + 2 ) of the first media distribution unit ( 10 . 10a - 10n + 2 ) as well as the second sealing element ( 13 . 13a - 13n + 2 ) of the second media distribution unit ( 10 . 10a - 10n + 2 ) each at least a portion of the at least partially between the respective mutually arranged second sealing elements ( 13 . 13a - 13n + 2 ) of the media distribution units ( 10 . 10a - 10n + 2 ) can be arranged first sealing element ( 2 . 2a - 2n + 1 ) of the membrane-electrode unit ( 1 . 1a - 1n + 1 ) to contact.

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