DE102019220599A1 - Foil for a foil system, foil MEA system with foil system, fuel cell stacks with foil MEA system as well as method for producing a foil MEA system - Google Patents

Abstract

Foil (1) for a foil system (20) of a fuel cell of a fuel cell stack (200), the fuel cell stack (200) comprising a plurality of fuel cells with bipolar plates (110) arranged one above the other and a membrane-electrode unit (120) per fuel cell, in which Foil (1) at least one stackable deformation (10) is formed.

Description

State of the art

A fuel cell is an electrochemical cell, which has two electrodes which are separated from one another by means of an ion-conducting electrolyte. The fuel cell converts the energy of a chemical reaction between a fuel and an oxidizing agent directly into electricity. A fuel cell has an anode and a cathode. There are different types of fuel cells.

A special type of fuel cell is the polymer electrolyte membrane fuel cell (PEM-FC). In an active area of a PEM-FC, two porous electrodes with a catalyst layer adjoin a polymer electrolyte membrane (PEM). The PEM-FC also includes gas diffusion layers (GDL) in the active area, which delimit the polymer electrolyte membrane (PEM) and the two porous electrodes with a catalyst layer on both sides. The PEM, the two electrodes with the catalyst layer and the two GDL form a so-called membrane electrode unit (MEA) in the active area of the PEM-FC. Two adjacent bipolar plates, in turn, delimit the MEA on both sides. A fuel cell stack is made up of MEA and bipolar plates arranged alternately on top of one another. The fuel, in particular hydrogen, is distributed with an anode plate of a bipolar plate, and the oxidizing agent, in particular air / oxygen, is distributed with a cathode plate of the bipolar plate. So that no electrical short circuit occurs between the bipolar plates in an inactive area of the PEM-FC surrounding the active area of the PEM-FC, the MEA, in particular the edge of the PEM of the MEA, is laminated between two electrically insulating foils. This means that the bipolar plates arranged one above the other in the inactive area of the PEM-FC are electrically isolated from one another.

In order to simplify the stacking of MEA and bipolar plates to form a fuel cell stack, the bipolar plates and the foils arranged between the bipolar plates can be stacked by means of a device with mechanical stops. Because of these laterally arranged mechanical stops, the foils cannot protrude over the edge of the bipolar plate. Because of manufacturing tolerances of the insulation foils or because of inaccurate positioning of the insulation foils, there is therefore the risk of an electrical short circuit occurring at these points between adjacent bipolar plates. Furthermore, bipolar plates can have unwanted bending, bend during a stacking process or when a fuel cell stack is braced, so that there is also the risk of an electrical short circuit here. Optical measuring methods can also be used when a fuel cell stack is produced by machine. However, these are expensive to purchase and commission. Furthermore, the stacking of MEA and bipolar plates to form a fuel cell stack with optical measurement methods is time-consuming.

From the DE202017107797U1 an electrochemical system with two separator plates and fixing elements for fixing the separator plates is known. Disadvantageously, the positioning of a frame section of the membrane between two separator plates is only possible imprecisely, so that an electrical short circuit can occur between adjacent bipolar plates. Furthermore, the arrangement of the membrane with the frame section is very time-consuming.

Disclosure of the invention

The present invention shows a film according to the features of claim 1, a film MEA system according to the features of claim 8, a fuel cell stack according to the features of claim 9 and a method according to the features of claim 12.

Further features and details of the invention emerge from the subclaims, the description and the drawings. Features and details that are described in connection with the film according to the invention naturally also apply in connection with the film MEA system according to the invention, the fuel cell stack according to the invention and the method according to the invention and vice versa, so that with regard to the disclosure to the individual aspects of the invention, there is always mutual reference is or can be taken.

According to a first aspect, the present invention shows a film for a film system of a fuel cell of a fuel cell stack, the fuel cell stack comprising a plurality of fuel cells with bipolar plates arranged one above the other and one membrane electrode unit per fuel cell. Furthermore, at least one stackable deformation is formed in the film.

The expression “essentially”, such as essentially perpendicular to a direction, can be used to express that slight deviations, for example due to manufacturing tolerances, are also included in the invention.

The film can be gas-tight and / or high heat resistance and / or high mechanical strength and / or high chemical Have persistence. Such a film can thus be particularly advantageously suitable for the fuel cell stack. Furthermore, the film can have recesses, for example for the arrangement of a membrane-electrode unit or for supply channels, so-called ports, of the fuel cell stack. In particular, the film can be designed in the form of a frame, with the membrane-electrode unit being able to be arranged particularly advantageously in the recess of the frame-shaped film.

The at least one stackable deformation of the film according to the invention can be understood as a stackable deformation which is designed to accommodate an element with a stackable deformation, in particular a further film according to the invention with the same stackable deformation, in such a way that the film according to the invention and the element contact each other flat . A bipolar plate with a correspondingly designed and arranged stackable bipolar plate deformation can also be understood as an element. In other words, the film according to the invention and the element can make flat contact on the one hand at the stackable deformation, but on the other hand also make flat contact outside the stackable deformation. It can thus advantageously be ensured that the fuel cell stack can continue to be operated particularly advantageously despite the stackable deformations. The bipolar plates and the film MEA systems with the membrane electrode units can be positioned particularly precisely with respect to one another and contact one another in a particularly advantageous manner. Furthermore, a short circuit between two adjacent bipolar plates of the fuel cell stack can thus also be avoided in a particularly advantageous manner. For a planar contact, the thickness of the at least one stackable deformation of the film can be less than the thickness of the film outside of the stackable deformation. This can be the case, for example, due to a lamination process. In addition, the thickness of the at least one stackable bipolar plate deformation of the bipolar plate can also be less than the thickness of the bipolar plate outside of the stackable bipolar plate deformation for a planar contact.

The at least one stackable deformation in the film can be formed by a lamination process. It is also conceivable that the at least one stackable deformation in the film is carried out by a hot stamping process or by a hot forming process, ie. H. under the application of pressure and heat, is formed in the film. The at least one stackable deformation can thus be formed in the film in a particularly simple and rapid manner. Furthermore, the at least one stackable deformation can thus be reproduced particularly well in the film. Stacking the bipolar plates and the foil MEA system with foils according to the invention to form the fuel cell stack can therefore take place particularly quickly and precisely. Furthermore, a short circuit between two adjacent bipolar plates of the fuel cell stack can thus also be avoided in a particularly advantageous manner.

With the film according to the invention or the film MEA system according to the invention, the bipolar plates and the film MEA system can thus be stacked in a particularly simple and fast manner to form the fuel cell stack with the bipolar plates and film MEA system arranged alternately on top of one another. For example, a film MEA system according to the invention can have a stackable deformation and a bipolar plate can likewise have a corresponding stackable bipolar plate deformation. The bipolar plate has been placed on the fuel cell stack. According to the invention, the film MEA system according to the invention can now be placed on the bipolar plate with the corresponding stackable deformation. Due to the stackable deformation of the foil MEA system and the corresponding stackable bipolar plate deformation of the bipolar plate, the foil MEA system can position itself independently. The expression "corresponding stackable bipolar plate deformation" is intended to express that the position of the stackable deformation of the film MEA system and the corresponding stackable bipolar plate deformation in the respective film should match in position such that a fuel cell stack is operated, in particular can be operated optimally. The film MEA system does not have to be placed exactly on the bipolar plate; a rough alignment can be sufficient. Due to the stackable bipolar plate deformation of the bipolar plate, the foil MEA system with the stackable deformation can slide like a slide onto the foil MEA system and position itself independently. Advantageously, an improved arrangement of bipolar plates and foil MEA systems can thus be achieved and the output of the fuel cell stack can be particularly high. Expensive stacking devices that use optical measuring methods can be dispensed with. Furthermore, the arrangement of bipolar plates and foil MEA systems to the fuel cell stack can be done particularly quickly and easily. Since laterally arranged mechanical stops can be omitted for stacking, at least one of the two foils of the foil system of the foil MEA system can stand or protrude over an edge of the bipolar plates, preferably the edge of the bipolar plates. A short circuit between two bipolar plates, in particular at the edge of the bipolar plates, can thus be particularly advantageously avoided.

Advantageously, a film according to the invention can have at least one laminatable material exhibit. The film can have polyethylene naphthalate (PEN) as the at least one laminatable material. In other words, the film can be a PEN film. Advantageously, PEN can have a particularly advantageous gas tightness, heat resistance, mechanical strength, high chemical resistance and particularly low electrical conductivity. The PEN film can thus be particularly advantageously suitable for the fuel cell stack and particularly advantageously avoid an electrical short circuit between two adjacent bipolar plates. The film is dimensionally stable, especially after a lamination process. What is meant by this is that the film is resistant to pressure and / or heat and essentially retains its shape under pressure. It can thus advantageously be ensured that the at least one stackable deformation retains its shape and the bipolar plates and the film MEA system can be stacked to form the fuel cell stack particularly quickly and precisely. Furthermore, a short circuit between two adjacent bipolar plates of the fuel cell stack can thus also be avoided in a particularly advantageous manner.

It can be advantageous if the film according to the invention is designed to be electrically insulating for the electrical separation of the two adjacent bipolar plates in the inactive area of the fuel cell. Advantageously, at least one of the two films of the stackable film system of the film MEA system, which are arranged next to one another, is designed to be electrically insulating. A short circuit between two adjacent bipolar plates in a fuel cell stack can thus be prevented in a particularly simple manner. Preferably, both of the two foils of the stackable foil system arranged next to one another are designed to be electrically insulating, in particular the two foils arranged next to one another being PEN foils. A particularly effective and safe electrical insulation can thus be provided.

In the case of a film according to the invention, the at least one stackable deformation can advantageously be extended in an extension direction perpendicular or essentially perpendicular to the longitudinal direction of the film. To provide the film, the film can be wound on a spool. The film can be unwound from the spool so that the film lies in one plane. The longitudinal direction of the film can be understood as a direction along the plane of the film. The expression that the at least one stackable deformation extends in an extension direction perpendicular or substantially perpendicular to the longitudinal direction of the film can mean that the at least one stackable deformation protrudes from the plane of the film. Thus, a further film according to the invention with likewise at least one correspondingly arranged stackable deformation can be arranged particularly easily on the film according to the invention with the at least one stackable deformation. The expression “appropriately arranged” is intended to express that the position of the at least one stackable deformation or the at least one correspondingly arranged stackable deformation in the respective film should match, so that the membrane-electrode unit of the film MEA system is between the two foils, in particular in a recess, can be arranged. A particularly good arrangement of bipolar plates and foil MEA systems can thus advantageously be achieved and the output of the fuel cell stack can be particularly high. Furthermore, short circuits between adjacent bipolar plates can be prevented particularly reliably. Furthermore, the arrangement of bipolar plates and foil MEA systems to the fuel cell stack can be done particularly quickly and easily. At least one of the two films of the film system of the film MEA system can protrude over an edge of the bipolar plates, preferably the edge of the bipolar plates. A short circuit between two bipolar plates can thus be avoided in a particularly advantageous manner.

• - eine Parabel-, Hyperbel- oder Ellipsenschnittfläche,
• - eine Kreissegmentfläche, insbesondere eine Halbkreisfläche,
• - eine Vielecksschnittfläche, insbesondere eine Dreiecksfläche oder Vierecksfläche.

With a film according to the invention, the cross-sectional area of the at least one stackable deformation can particularly advantageously decrease in a direction away from the film along the direction of extent. The at least one stackable deformation can thus be stackable in a particularly advantageous manner. Because the cross-sectional area of the at least one stackable deformation decreases in the direction away from the film along the direction of extension, the second film of the stackable film system of the film MEA system can have the same stackable deformation. It is thus possible to use the same, in particular identical, inventive foils for foil systems of the foil MEA systems of the fuel cell stack. It can also be particularly advantageously ensured that the two films of the stackable film system of the film MEA system, which are arranged next to one another, can make flat contact on the one hand at the stackable deformation, but can also make flat contact outside the stackable deformation on the other hand. The at least one deformation can advantageously have one of the following surface shapes in a vertical section and / or in a cross section:

• - a parabolic, hyperbolic or elliptical section,
• - a circle segment area, in particular a semicircle area,
• - A polygonal section surface, in particular a triangular surface or a quadrangular surface.

In particular, the at least one stackable deformation can taper to a point in the direction away from the film along the direction of extent, in particular it can be conical. The at least one stackable deformation can also be dome-shaped or pyramid-shaped. Deformations in which there is also no freedom of rotation about the direction of extent, for example the pyramidal deformation, can be particularly advantageous. Here, a deformation formed in the film can already be sufficient for a particularly precise alignment of two films with respect to one another. Furthermore, the tangents on the lateral surface of the at least one deformation can enclose an angle between 0 ° and 85 ° with the plane of the film. It can thus be ensured in a particularly advantageous manner that the deformation can be stacked.

According to a further preferred embodiment, at least two stackable deformations can be formed in a film. The two foils of the stackable foil system that are arranged next to one another can thus be positioned particularly precisely with respect to one another and a membrane-electrode unit can be arranged particularly easily and precisely between the two foils. The arrangement of bipolar plates and film MEA systems on top of one another can also be carried out particularly accurately and the fuel cell stack can be operated particularly advantageously. The at least two stackable deformations can also prevent slipping or twisting, for example two films according to the invention arranged one above the other, in an improved manner. Slipping or twisting, for example two foils according to the invention arranged one above the other, can be particularly advantageously prevented by three stackable deformations. The at least two stackable deformations can each have a different shape. It is also conceivable that the at least two stackable deformations have the same shape.

It can be advantageous if, in a film according to the invention, the at least two stackable deformations are each formed in the region of an edge or in the region of a corner of the film, in particular the at least two stackable deformations being opposite one another. The expression “in the area of an edge” can be understood as “close to an edge”. Furthermore, the expression “in the area of a corner” can also be understood as “near a corner”. The film according to the invention can have the dimensions, in particular essentially the dimensions, of the bipolar plates of the fuel cell stack. As already mentioned, the film according to the invention can additionally have recesses, for example for receiving the membrane-electrode unit or for the ports of the bipolar plate. The film or the film system can advantageously protrude over an edge of the bipolar plate. The edge of the bipolar plate or the film or the film system can be understood to be a delimitation of an area of the bipolar plate or the film or the film system. The edge of the bipolar plate or the film or the film system can be understood to be an edge, in particular the edge delimiting the bipolar plate or the film or the film system. Furthermore, the edge of the bipolar plate or the film or the film system can be a port edge which borders or encloses a so-called port. Ports can be understood as openings in the bipolar plate or the foil or the foil system, which form guide channels in the fuel cell stack for guiding fluids, such as cathode gas, anode gas and cooling fluid, to and from the bipolar plates arranged one above the other. Because the film or film system protrudes from the edges of the bipolar plate, a short circuit between adjacent bipolar plates can be prevented in a particularly advantageous manner. Advantageously, on an outer edge of the bipolar plate delimiting the bipolar plate, no channels for guiding a fluid, such as e.g. B. cathode gas, anode gas and / or cooling fluid. The at least one stackable deformation of the film according to the invention or the stackable deformation of the film MEA system or the stackable deformation of the bipolar plate of the fuel cell is thus preferably located at the respective delimiting edge. This can ensure that a function of the fuel cell stack is not impaired by the respective stackable deformations. The at least two stackable deformations can each be formed particularly easily in one corner of the film, in particular in opposite corners. Very advantageously, the at least two stackable deformations can be formed in diagonally opposite corners. It is also conceivable that the at least two stackable deformations are formed in the area of two opposite longitudinal sides of the film or two opposite transverse sides of the film. Slipping or twisting, for example two films according to the invention arranged one above the other, can thus be prevented in a particularly advantageous manner.

According to a second aspect, the present invention shows a film MEA system for arrangement between two bipolar plates of a fuel cell stack, the film MEA system having a stackable film system with two films according to the invention arranged next to one another. Furthermore, the film MEA system has a membrane electrode unit which is at least partially arranged between the two films.

In the context of the invention, a bipolar plate at the two ends of the fuel cell stack can also be understood as a monopolar plate. A film MEA system according to the invention can thus also be arranged between a monopolar plate and a bipolar plate.

The membrane-electrode assembly can comprise a polymer electrolyte membrane (PEM). The membrane-electrode unit can furthermore comprise two porous electrodes, each with a catalyst layer, wherein these can be arranged on the PEM and delimit on both sides. One can speak of an MEA-3 here. In addition, the membrane-electrode unit can comprise two gas diffusion layers. In particular, these can limit the MEA-3 on both sides. One can speak of an MEA-5 here. The dimensions of the PEM can in particular be larger than the dimensions of the porous electrodes and the gas diffusion layers. In particular, the PEM of the MEA-3 or the MEA-5 has a circumferential edge. The MEA-3 or MEA-5 can be arranged at least partially in a recess of the two films according to the invention between the two films according to the invention. In particular, only the circumferential edge of the PEM of the MEA-3 or the MEA-5 can be arranged between the two films. The arrangement of the membrane-electrode unit between the two foils can be understood as a cohesive arrangement, in particular by means of a lamination process. The at least one stackable deformation of the two foils is advantageously arranged where the membrane-electrode unit is not arranged between the two foils. A particularly advantageously stackable deformation can thus be formed.

The two foils according to the invention arranged next to one another can be congruent. In other words, the foils can be identical. This can mean that the two films can have the same dimensions, in particular essentially the same dimensions and / or recesses. The recess can be a recess for the membrane-electrode unit and can advantageously be square. The film according to the invention can thus have a frame shape. It is also conceivable that one of the two films has larger dimensions than the other film, so that a short circuit between two adjacent bipolar plates can be particularly advantageously avoided. Larger dimensions can be understood to mean that the film is longer and / or wider. In particular, the two foils also have the same at least one stackable deformation in the same position, in particular in the same position in such a way that recesses in the two foils are aligned one above the other. The stackable film system can thus be created in a particularly simple manner.

The film MEA system according to the second aspect of the invention thus has the same advantages as have already been described for the film according to the first aspect of the invention.

According to a third aspect, the present invention shows a fuel cell stack with two bipolar plates, a film MEA system according to the invention being arranged between the two bipolar plates.

With the film MEA system according to the invention, the fuel cell stack can be operated or manufactured particularly advantageously. The bipolar plates and the film MEA systems with the membrane electrode units can be positioned particularly precisely with respect to one another and contact one another in a particularly advantageous manner. A short circuit between two adjacent bipolar plates of the fuel cell stack can thus be avoided in a particularly advantageous manner. In addition, the stacking of the bipolar plates and the film MEA systems to form the fuel cell stack can take place particularly quickly.

It can be advantageous if, in a fuel cell stack according to the invention, at least one stackable bipolar plate deformation is formed in the two bipolar plates corresponding to the at least one stackable deformation of the film system of the film MEA system. This means that the stacking of the bipolar plates and the film MEA system can be carried out particularly accurately and quickly. The expression "corresponding stackable bipolar plate deformation" can be understood to mean that the position of the stackable deformation of the film MEA system and the corresponding stackable bipolar plate deformation in the respective film should match in position such that a fuel cell stack can be operated particularly advantageously can.

In a fuel cell stack according to the invention, at least one of the two foils of the foil system can advantageously protrude at least partially over at least one edge of the two bipolar plates. A short circuit between the two bipolar plates can thus be prevented in a particularly advantageous manner. In particular, the stackable film system can protrude beyond the respective outer edge of the bipolar plates. The stackable film system can advantageously also protrude beyond the port edges. In other words, the stackable film system can protrude into the port.

The fuel cell stack according to the third aspect of the invention thus has the same Advantages as they have already been described for the film according to the first aspect of the invention or the film MEA system according to the second aspect of the invention.

1. a) Bereitstellen einer ersten Folie,
2. b) Anordnen einer Membran-Elektroden-Einheit mit einer ersten Seite an die erste Folie,
3. c) Anordnen einer zweiten Folie an eine zweite Seite der Membran-Elektroden-Einheit,
4. d) Prägen, Umformen und/oder Laminieren der ersten Folie, der Membran-Elektroden-Einheit und der zweiten Folie zu dem Folien-MEA System mit dem stapelbaren Foliensystem.

According to a fourth aspect, the present invention shows a method for producing a film MEA system according to the invention, the method comprising the following steps:

1. a) providing a first film,
2. b) arranging a membrane-electrode unit with a first side on the first film,
3. c) arranging a second film on a second side of the membrane-electrode unit,
4. d) Embossing, reshaping and / or lamination of the first film, the membrane-electrode unit and the second film to form the film MEA system with the stackable film system.

In step a), the first film can be provided by an injection molding process or by injection molding. Recesses in the first film can be taken into account in the injection molding. It is also conceivable that the first film is provided on a reel. Such a first film can be unwound from the spool, laid out flat and cut to size in an additional step. In particular, the first film can be cut to size according to the dimensions of the bipolar plates of the fuel cell stack. With the cutting to size, the recesses, in particular the recess for the membrane-electrode unit and / or ports, can also be made in the first film. In the following step b) the membrane-electrode unit is arranged with the first side on the first film. In particular, the membrane-electrode unit is arranged on the recess for the membrane-electrode unit. By arranging it can be meant here that the membrane-electrode unit is placed on the first film, in particular on the recess. The membrane-electrode unit, in particular the PEM of the membrane-electrode unit, and the first film advantageously overlap. In the following step c), the second film is arranged on the second side of the membrane-electrode unit. In particular, the second film is arranged on the second side of the membrane-electrode unit in such a way that the second film and the first film are aligned one above the other. The second film can be arranged by an injection molding process or by injection molding. It is also conceivable that the second film is provided on a reel and, as already described above, is additionally cut to size. The second film can be placed here on the membrane-electrode unit. In the following step d), the first film, the membrane electrode unit and the second film can be embossed, reshaped and / or laminated to form the film MEA system with the stackable film system. The embossing and the reshaping can take place, for example, by a hot embossing process or by a hot forming process.

It is also conceivable that the at least one stackable deformation is formed in each of the first and second foils before the membrane-electrode unit is arranged on the first foil, for example by a hot stamping process or by a hot forming process. The two foils according to the invention can thus be arranged on one another particularly accurately and quickly.

The method according to the fourth aspect of the invention thus has the same advantages as already described for the film according to the first aspect of the invention or the film MEA system according to the second aspect of the invention or the fuel cell stack according to the third aspect of the invention have been.

Further measures improving the invention emerge from the following description of some exemplary embodiments of the invention, which are shown schematically in the figures. All of the features and / or advantages arising from the claims, the description or the drawings, including structural details, spatial arrangements and method steps, can be essential to the invention both individually and in the various combinations. It should be noted that the figures are only of a descriptive character and are not intended to restrict the invention in any way.

• 1 in einer perspektivischen Ansicht einen Teil einer erfindungsgemäßen Folie einer Ausführungsform,
• 2 in einer Draufsicht eine weitere Ausführungsform einer erfindungsgemäßen Folie,
• 3 in einer Draufsicht eine Ausführungsform eines erfindungsgemäßen Folien-MEA Systems,
• 4 in einer perspektivischen Ansicht einen Teil eines erfindungsgemäßen Brennstoffzellenstapels in einer Ausführungsform,
• 5 in einer perspektivischen Ansicht einen Vertikalschnitt durch den Teil des erfindungsgemäßen Brennstoffzellenstapels in der in 4 illustrierten Ausführungsform,
• 6 in einer Draufsicht eine weitere Ausführungsform eines erfindungsgemäßen Brennstoffzellenstapels, und
• 7 eine Ausführungsform eines erfindungsgemäßen Verfahrens zum Herstellen eines Folien-MEA Systems.

They show schematically:

• 1 in a perspective view a part of a film according to the invention of an embodiment,
• 2 a top view of a further embodiment of a film according to the invention,
• 3 in a plan view an embodiment of a film MEA system according to the invention,
• 4th in a perspective view a part of a fuel cell stack according to the invention in one embodiment,
• 5 in a perspective view a vertical section through the part of the fuel cell stack according to the invention in FIG 4th illustrated embodiment,
• 6th a top view of a further embodiment of a fuel cell stack according to the invention, and
• 7th an embodiment of a method according to the invention for producing a film MEA system.

In the following figures, identical reference symbols are used for the same technical features from different exemplary embodiments.

1 shows a perspective view of part of a film according to the invention 1 one embodiment. In the slide 1 is a stackable deformation 10 educated. The stackable deformation 10 is perpendicular in an extension direction ER or essentially perpendicular to the longitudinal direction LR of the film 1 extends. The cross-sectional area of the stackable deformation 10 takes in one direction away from the slide 1 along the direction of extension ER. The stackable deformation runs as an example 10 in 1 pointed, in particular this is conical here.

2 shows a plan view of a further embodiment of a frame-shaped film according to the invention 1 . The foil 1 points for a membrane electrode assembly 120 a square recess 5 on. Next includes the slide 1 six square recesses 4th for the ports of a bipolar plate 110 . There are also two opposite corners 13a , 13b , especially in the area of the corners 13th , each a stackable deformation 10a or. 10b educated. These extend in an extension direction ER perpendicular or essentially perpendicular to the longitudinal direction LR of the film 1 . It is also conceivable that the two stackable deformations 10a , 10b on an edge 12a or on an edge 12b are trained. The edge 12a represents an outer edge of the film 1 and the edge 12b a port edge.

3 shows an embodiment of a film MEA system according to the invention in a plan view 40 . The foil MEA system 40 includes a stackable film system 20th with two foils arranged next to and one above the other 1a , 1b . The two slides 1a , 1b are so by their respective stackable deformation 10a , 10b arranged next to each other that respective recesses 5a or. 5b lie flush on top of each other. This ensures that a membrane-electrode unit 120 between the two slides 1a , 1b can be arranged particularly advantageously. The membrane-electrode unit 120 is in 3 represented by the continuous lines and the dashed lines, with a circumferential edge of the membrane-electrode unit 120 between the two slides 1a , 1b is arranged. The stackable deformations 10a , 10b extend in an extension direction ER perpendicular or substantially perpendicular to the longitudinal direction LR of the film 1 . The stackable deformations are exemplary 10a , 10b pyramidal shape. Such a film MEA system 40 that is on a bipolar plate 110 with a correspondingly arranged and designed pyramid-shaped bipolar plate deformation 111 is placed, can particularly advantageously enable the arrangement and positioning with respect to one another in a simple manner. Furthermore, a single such pyramidal deformation can already be achieved 10 in the elements of the fuel cell stack 200 be enough. The pyramidal deformation 10 or. 111 can already prevent twisting and slipping of two superimposed elements.

4th shows a perspective view of part of a fuel cell stack according to the invention 200 in one embodiment. In 4th are bipolar plates 110 and foil MEA systems 40 arranged alternately one above the other, in particular the stackable film systems 20th the foil MEA system 40 with the stackable deformations 10 are shown. 5 shows a perspective view of a vertical section through the part of the fuel cell stack according to the invention 200 in the in 4th illustrated embodiment. You can see here that the film system 20th and the bipolar plates 110 on the one hand to the stackable deformation 10 or. 111 Contact flat, but also on the other hand outside of the stackable deformations 10 or. 111 contact extensively. It can thus advantageously be ensured that the fuel cell stack 200 can still be operated particularly advantageously despite the stackable deformations. The bipolar plates 110 and the foil MEA systems 40 with the membrane electrode units 120 can therefore be positioned particularly precisely with respect to one another and contact one another in a particularly advantageous manner.

6th shows a plan view of a further embodiment of a fuel cell stack according to the invention 200 . For the sake of simplicity, there are only one bipolar plate 110 and a foil MEA system 40 shown. The bipolar plate 110 is represented by the two lined areas. The inner lined area is an active area of the bipolar plate 110 or the fuel cell stack 200 represents. The outer lined area represents the inactive area 102 the bipolar plate 110 The bipolar plate 110 is above the foil MEA system 40 arranged. In 6th you can see that the stackable film system 20th over the outer edge 112a the bipolar plate 110 survives. Next is in 6th shown that the stackable film system 20th also over the port edges 112b the bipolar plate 110 protrudes or in the port edges 112b stands in it. Thus, a particularly advantageous Short circuit between two adjacent bipolar plates 110 be prevented.

In addition, in 6th in an inactive area 102 each a stackable deformation 10 or a stackable bipolar plate deformation 110 formed in the area of two opposite longitudinal sides.

7th shows an embodiment of a method according to the invention for producing a film MEA system 40 . In a first step, a film according to the invention is made 1a provided 302 . Is the slide 1a wound on a spool, this can then be cut to size in an additional step. Then a membrane-electrode assembly 120 with a first side on the first slide 1a arranged 306 . The next step is the second slide 1b to the second side of the membrane-electrode assembly opposite the first side 120 arranged 308 . The next step is the first slide 1a , the second slide 2a and the one between the two foils 1a , 1b arranged membrane-electrode unit 120 to the film MEA system according to the invention 40 embossed, formed and / or laminated.

QUOTES INCLUDED IN THE DESCRIPTION

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Patent literature cited

• DE 202017107797 U1 [0004]

Claims (12)

Foil (1) for a foil system (20) of a fuel cell of a fuel cell stack (200), the fuel cell stack (200) comprising a plurality of fuel cells with bipolar plates (110) arranged one above the other and a membrane-electrode unit (120) per fuel cell, in which Foil (1) at least one stackable deformation (10) is formed. Slide (1) Claim 1 , characterized in that the film (1) has at least one laminable material. Slide (1) Claim 1 or 2 , characterized in that the film (1) is designed to be electrically insulating for the electrical separation of two adjacent bipolar plates (110) of the fuel cell stack (200) in the inactive area (102) of the fuel cell. Foil (1) according to one of the preceding claims, characterized in that the at least one stackable deformation (10) extends in an extension direction (ER) perpendicular or substantially perpendicular to the longitudinal direction (LR) of the foil (1). Slide (1) Claim 4 , characterized in that the cross-sectional area of the at least one stackable deformation (1) decreases in a direction away from the film (1) along the direction of extension (ER). Foil (1) according to one of the preceding claims, characterized in that at least two stackable deformations (10) are formed in the foil (1). Slide (1) Claim 6 , characterized in that the at least two stackable deformations (10) are each formed in the area of an edge (12) or in the area of a corner (13) of the film (1), in particular the at least two stackable deformations (10) being opposite one another. Foil MEA system (40) for arrangement between two bipolar plates (110) of a fuel cell stack (200), the foil MEA system (40) having: - A stackable film system (20) with two films (1) arranged next to one another, each according to one of the preceding claims, - A membrane-electrode unit (120) which is at least partially arranged between the two foils (1). Fuel cell stack (200) with two bipolar plates (110), with a film MEA system (40) between the two bipolar plates (110) according to FIG Claim 8 is arranged. Fuel cell stack (200) after Claim 9 , characterized in that at least one stackable bipolar plate deformation (111) is formed in the two bipolar plates (110) corresponding to the at least one stackable deformation (10) of the film system (20) of the film MEA system (40). Fuel cell stack (200) after Claim 9 or 10 , characterized in that at least one of the two foils (1) of the foil system (20) is at least partially in each case over at least one edge (112) of the two bipolar plates (110). Method for producing a film MEA system (40) according to Claim 8 , the method comprising the following steps: a) providing (302) a first film (1a), b) arranging (306) a membrane-electrode unit (120) with a first side on the first film (1a), c) Arranging (308) a second film (1b) on a second side of the membrane-electrode unit (120) d) embossing, reshaping and / or laminating (310) the first film (1a), the membrane-electrode unit (120) ) and the second film (1b) to form the film MEA system (40) with the stackable film system (20).

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