Sealing device for fuel cell

Abstract

The invention relates to a sealing device (10) for use in a fuel cell (20) having a first sealing section (1) and a second sealing section (2) which can be arranged on opposite sides of a membrane (3), in particular a subgasket, and which can prevent a medium flow along the membrane (3), wherein at least one of the two sealing sections (1, 2) has a plurality of sealing lips (2.1) arranged next to one another for tolerance compensation.

Description

[0001] The invention relates to a sealing device for use in a fuel cell having a first sealing section and a second sealing section which can be arranged on opposite sides of a membrane, in particular a subgasket, and which can prevent a medium flow along the membrane.

[0002] Fuel cells, especially polymer electrolyte fuel cells, which are used in many areas of technology, have a layered structure with very thin channels to achieve the highest possible power density. However, these thin layers place particularly high demands on the seals, as the low channel heights generally prevent large seal compressions. Furthermore, the individual layers must be positioned very precisely to ensure adequate sealing, and even small tolerance deviations can lead to leaks.

[0003] In a fuel cell, two media are separated from each other by a membrane at several points, and flow along the membrane must be prevented at certain points. For this purpose, sealing devices with two sealing sections are known to be used, with a first sealing section on one side of the membrane and the other sealing section on the opposite side of the membrane, thus preventing flow along the membrane at certain points on each side. Because the membrane is flexible, the two sealing sections must be aligned as precisely as possible and face each other, otherwise the sealing sections cannot exert sufficient contact force on the membrane. Even minor assembly or manufacturing deviations can therefore result in sufficient sealing no longer being guaranteed.

[0004] Based on this, the invention sets itself the task of providing a sealing device which is characterized by a more reliable seal.

[0005] This object is achieved in a sealing device of the type mentioned at the outset in that at least one of the two sealing sections has a plurality of sealing lips arranged next to one another for tolerance compensation.

[0006] Due to the multiple sealing lips arranged next to each other, it is not absolutely necessary for the two sealing sections to be arranged exactly in a line or to be exactly opposite each other with regard to the diaphragm. Rather, depending on the position of the two sealing sections, the sealing effect can be created by the two sealing lips that are opposite each other with regard to the diaphragm. In this respect, a certain offset or deviation in the position of the two sealing sections transverse to the longitudinal direction of the sealing lips compared to a predetermined position can be prevented from leading to leaks. The second sealing section advantageously has multiple sealing lips arranged next to each other to compensate for tolerances, i.e. to compensate for manufacturing and / or assembly deviations, as will be explained in more detail below.

[0007] The sealing lips of the two sealing sections can run parallel. The sealing line can therefore extend in the longitudinal direction of the sealing lips, and the sealing effect can reliably prevent medium flow perpendicular to the longitudinal direction of the sealing lips. The sealing sections can have an alternating profile of wave crests and wave troughs in cross-section, whereby the wave crests represent the actual sealing lips and the sealing effect is therefore essentially generated by the contact of the wave crests with the membrane. To generate the sealing effect, the sealing lips can be compressed or deformed in the elastic range, in particular via a compressive force acting in the normal direction to the membrane. This compressive force can therefore also hold the individual layers of the fuel cell together and counteract the internal pressure of the medium flowing in the channels.Potentially, the pressure force required to compress the sealing sections must be greater the greater the internal pressure or the pressure of the medium flowing in the channels to be sealed.

[0008] According to an advantageous development of the invention, the first sealing section has an odd number of sealing lips, in particular three sealing lips. An odd number of sealing lips ensures that one of the sealing lips is located in the center of the sealing section and that the number of sealing lips located to the left and right of this central sealing lip is identical.

[0009] It is advantageous if the sealing lips of the first sealing section have different heights, which then also results in different contact pressures on the diaphragm and thus a different sealing effect. It has proven particularly advantageous if the middle sealing lip of the first sealing section has a greater height than the other sealing lips of the first sealing section. The other sealing lips can have the same height, and the middle sealing lip can protrude from the other sealing lips. In this respect, the highest contact pressure on the diaphragm and thus the best sealing effect are achieved in the area of ​​the middle sealing lip.

[0010] The purpose of the remaining sealing lips is therefore not necessarily to achieve a direct sealing effect alongside the center sealing lip. Rather, the remaining sealing lips can be designed to stabilize the center sealing lip and ensure the most reliable sealing effect possible in the area of ​​the center sealing lip. For this purpose, a supporting force can flow from the side sealing lips toward the center sealing lip.

[0011] With regard to the second sealing section, it has proven advantageous if it has an odd number of sealing lips arranged next to one another. For example, the second sealing section can have five or seven sealing lips arranged next to one another. Furthermore, the number of sealing lips in the second sealing section can be greater than the number of sealing lips in the first sealing section. In this respect, the second sealing section in particular can ensure tolerance compensation, since the middle sealing lip, which primarily ensures the sealing effect on the side of the first sealing section, can be opposite different sealing lips of the second sealing section depending on the position of the two sealing sections.

[0012] With regard to the design of the sealing lips of the second sealing section, it has proven advantageous if they have the same height. The second sealing section can have a wave shape in cross-section consisting of several adjacent wave crests and troughs. Advantageously, the sealing line on the first sealing section side is thus formed by the contact line between the central sealing lip and the membrane, and on the second sealing section side, by the sealing lip opposite the central sealing lip of the first sealing section and the membrane.

[0013] Furthermore, it has proven advantageous if the sealing lips of the second sealing section are narrower than the sealing lips of the first sealing section. Due to the comparatively narrower sealing lips, a reliable sealing effect can be ensured even if the sealing sections are offset. For example, it can be provided that the middle sealing lip of the first sealing section lies opposite a predetermined sealing lip of the second sealing section and the sealing effect is then created accordingly between these two sealing lips and the diaphragm. However, if a certain offset transverse to the longitudinal direction of the sealing lips occurs during assembly, the sealing effect can then be ensured between the middle sealing lip of the first sealing section and the diaphragm as well as between another sealing lip of the second sealing section and the diaphragm.If the distance between the sealing lips of the second sealing section were too large, sufficient compression of the sealing lips could not be ensured, for example if the middle sealing lip of the first sealing section were arranged exactly opposite a valley between two sealing lips of the second sealing section.

[0014] To create a sealing effect on both sides of the diaphragm, it has proven advantageous if the sealing lips contact the diaphragm from opposite sides. In this respect, it can be provided that one of the sealing sections contacts the diaphragm from above and the other sealing section contacts the diaphragm from below. To create the sealing effect, the sealing sections can be pressed against the diaphragm with a certain force so that the sealing sections deform elastically. Advantageously, the compressive forces of the two sealing sections act on the diaphragm approximately in one axis so that the diaphragm is not deformed or deforms only to a very small extent, and a constant channel height is ensured on both sides of the diaphragm.

[0015] With regard to the sealing lips of the two sealing sections, it has proven advantageous if the sealing lips are elastically deformable to create the sealing effect. Due to this elastic deformability, the sealing lips can flatten in the area of ​​the diaphragm and then rest flat on the diaphragm in a certain area. This flattened area then primarily ensures the sealing effect between the diaphragm and the respective sealing section. Plastics, especially elastomers, have proven to be a suitable material. PTFE has proven particularly advantageous, particularly due to its good sealing effect and its good durability. It is advantageous for both sealing sections to be made of the same material, but different materials can also be used on the opposite sides of the diaphragm.

[0016] As already described above, the exact position of the two sealing sections and therefore also the exact position of the sealing lips depends on assembly or manufacturing deviations. In order to achieve the best possible sealing effect, it is advantageous if one of the sealing lips of the first sealing section, in particular the middle sealing lip, is opposite a sealing lip of the second sealing section. This means that two wave crests are as precisely opposite each other as possible and the diaphragm is contacted by the two wave crests on opposite sides at the same point. In this case, the two resulting sealing lines lie on top of each other and the flow of force can run in a straight line from one sealing lip through the diaphragm to the opposite sealing lip. This position ensures optimal sealing on both sides of the diaphragm.

[0017] Against this background, however, it is also possible for one of the sealing lips of the first sealing section, in particular the middle sealing lip, to be opposite a wave trough arranged between two sealing lips of the second sealing section. This can be the case in particular if there is a certain offset of the sealing sections due to manufacturing or assembly tolerances. With this arrangement or positioning, the sealing lip of the first sealing section, in particular the middle sealing lip, is therefore not opposite a wave crest of the second sealing section, but rather it is located exactly between two wave crests and therefore opposite a wave trough. This position represents the most unfavorable case for the seal, since the force flow does not flow from one wave crest across the diaphragm in a line to another wave crest, but rather because the force flow is split from the wave crest of the first sealing section across two wave crests of the second sealing section.The diaphragm is therefore not subjected to a compressive force from both sides at the same point, but rather the force is split between two points on the second sealing section side. Due to this force distribution, the sealing effect is reduced and this positioning creates two sealing lines on the second sealing section side, which overall result in a weaker sealing effect than a single sealing line. Although this positioning leads to a less reliable seal, the sealing device is advantageously designed in such a way that a sufficient sealing effect is still ensured even in this position. With a relative movement to the left or right starting from this position, the sealing effect can be improved because the distance between the two sealing lines on the second sealing section side is reduced.

[0018] With regard to the object mentioned above, a fuel cell, in particular a polymer electrolyte fuel cell, is further proposed, which has a membrane, in particular a subgasket, and a sealing device configured as described above. This results in the advantages already described with regard to the sealing device.

[0019] The term fuel cell refers not only to cells that generate electrical energy through the conversion of fuel, but also to cells that use electrical current to effect material conversion. These are sometimes also referred to as reversible fuel cells or electrolyzers.

[0020] The membrane can be a thin and flexible film that is impermeable to the medium on the two opposite sides of the membrane. However, the membrane can be designed as a cation exchange membrane, allowing cations to pass through the membrane from one side to the other. The membrane can be designed as a catalyst-coated membrane and consist of at least one, in particular two, PTFE films. Especially in the field of fuel cells and electrolyzers, such a membrane is also referred to as a subgasket.

[0021] With regard to the fuel cell, it has further proven advantageous if it has two metal sheets, in particular arranged parallel to one another, wherein the first sealing section is connected to the first metal sheet and the second sealing section is connected to the second metal sheet. In order for the sealing devices to be reliably connected to the respective metal sheets, they can be connected to the metal sheets in a form-fitting, force-fitting and / or material-fitting manner. Relative movement between the metal sheet and the sealing section can thus be avoided. The two metal sheets can be arranged on opposite sides of the membrane, so that a channel is created between the metal sheets and the membrane. The metal sheets can be arranged parallel to the membrane, resulting overall in a layered structure and a very flat design. The metal sheets can have a certain distance from the membrane, which can be ensured by the respective sealing sections.The sealing sections thus serve a dual function, ensuring not only a reliable seal but also a predefined channel height. It is advantageous if one of the sheets is designed as a screen plate and the other as a perforated plate. Screen and perforated plates are typical components of fuel cells.

[0022] With regard to the metal sheets, it has also proven advantageous if first sealing sections are arranged on both sides of the first metal sheet. In this respect, the metal sheet can be sealed against other elements on both sides. The design of the two first sealing sections can be identical, but the two first sealing sections can also be designed differently, for example with regard to the sealing lip height, the number of sealing lips or the sealing lip contour. It is also possible to have a first sealing section on one side and a second sealing section on the other side. “First” and “second” do not necessarily refer to the number of sealing sections, but rather to the design of the sealing sections, which was described above. Each side of the metal sheet is advantageously provided with a sealing section that reliably meets the sealing requirements.

[0023] With regard to the second sheet, it has proven advantageous if a first sealing section is arranged on one side of the second sheet and a second sealing section is arranged on the opposite side of the second sheet. The second sheet can also be sealed from other elements via the two sealing sections on both sides. Advantageously, the two sealing sections arranged on the two sides of the sheet differ from one another; however, identically designed sealing sections can also be arranged on both sides of the second sheet. Regarding the design of the sealing sections, reference is made to the above.

[0024] According to an advantageous development of the fuel cell, it is provided that it has two plates, in particular two bipolar plates, wherein the first and second sheets can be sealed against one of the plates on their side facing away from the membrane. Thus, a sealing section, in particular a first sealing section, can be arranged between each sheet and each plate. This ensures both a predefined and consistent distance between the plate and the sheet and a reliable seal. The plates can run essentially parallel to the sheets and thus also parallel to the membrane.

[0025] Further details and advantages of the invention will be explained in more detail below with reference to the accompanying drawings of an exemplary embodiment. In these drawings: Fig. 1 is an exploded view of part of a fuel cell; Fig. 2 a sectional side view of a part of a fuel cell according to Fig. 1; Fig. 3a - 3c perspective side views of two sheets in different positions.

[0026] The representation in the Fig. Figure 1 initially shows a section of a fuel cell 20 in an exploded view, which reveals the layered structure of the fuel cell 20. The basic functionality of the fuel cell 20 will not be explained in detail here.

[0027] In the presentation of the Fig. 1, five layers can be seen arranged one above the other. These are two bipolar plates 5.1, 5.2, two sheets 4.1, 4.2, and a membrane 3 arranged in the middle, which acts as a subgasket. As can be seen in particular from the illustration of the Fig. As can be seen in Figure 2, the individual layers are arranged essentially parallel to each other, and a thin gap is provided between each two adjacent layers. A medium can be located in this gap, which the fuel cell 20 according to the illustration in Figure 2. Fig. 2 in the viewing direction. Sealing sections 1, 2 are provided between the individual layers, which ensure that the layers have a fixed distance from each other and that the medium in the channels cannot pass through the sealing sections 1, 2. For example, based on the representation of the Fig. 2 between the membrane 3 and the upper plate 4.2, this medium cannot flow along the membrane 3 from left to right, since the sealing section 2, which will be explained in more detail below, prevents this and ensures a sealing effect between the plate 4.2 and the membrane 3.

[0028] The sealing effect of the two sheets 4.1, 4.2 arranged on opposite sides of the membrane 3 is primarily determined by the design of the two sealing sections 1, 2. The two sealing sections 1, 2 are coordinated with each other and are also referred to as sealing device 10. The design of the two sealing sections 1, 2 is shown, for example, in the illustration of the Fig. 1. The second sealing section 2, which is in contact with the upper side of the membrane 3, has a wave pattern in cross-section consisting of several sealing lips 2.1 arranged next to one another. The wave pattern is created by alternating wave troughs and wave crests, with the wave crests all having the same height and representing the actual sealing lips 2.1, which lead to a sealing effect upon contact with the membrane 3. In the illustration of the Fig. 1 it can be seen that the second sealing section 2 has a total of seven sealing lips 2.1 arranged next to one another and running parallel to one another.

[0029] On the other side of the membrane 3, the first sealing section 1 arranged on the first sheet 4.1 is in contact with the membrane 3. The first sealing section 1 differs from the second sealing section 2 in several respects. Firstly, the first sealing section 1, just like the second sealing section 2, has several sealing lips 1.1, 1.2, 1.3 running parallel to one another. However, the first sealing section 1 comprises a smaller number of sealing lips 1.1, 1.2, 1.3, and the sealing lips 1.1, 1.2, 1.3 do not all have the same height. This is because the middle of the three sealing lips 1.2 protrudes from the two outer sealing lips 1.1, 1.3, or the middle sealing lip 1.2 has a greater height than the other two sealing lips 1.1, 1.3. These different heights are particularly evident in the illustration of the Fig. 2 between the upper sheet 4.2 and the upper plate 5.2, as well as between the lower sheet 4.1 and the lower plate 5.1. The first sealing sections 1, featuring three sealing lips 1.1, 1.2, and 1.3, are also used in this area.

[0030] Because the membrane 3 is flexible, it is not possible to seal it from only one side, since to create the sealing effect, the sealing sections 1, 2 must be pressed onto the membrane 1 with a certain force. Rather, approximately equal forces must be applied from both sides of the membrane 3 through the two sealing sections 1, 2 so that a reliable sealing effect can be achieved on both sides, while the membrane 3 nevertheless retains its flat shape and does not bulge in one direction.

[0031] As can be easily imagined based on the sealing lips 1.1, 1.2, 1.3 with their different heights, when the layers are pressed together, the highest, middle sealing lip 1.2 first comes into contact with the underside of the membrane 3. Since the membrane 3 rests on the sealing lips 2.1 of the second sealing section 2 on the opposite side, it cannot escape. Instead, there is an elastic deformation of the middle sealing lip 1.2 as well as an elastic deformation of the sealing lip 2.1 or the sealing lips 2.1 on the other side of the membrane 3. Due to the greater height of the middle sealing lip 1.2, the other two sealing lips 1.1, 1.3 do not initially come into contact with the membrane 3. Only when the middle sealing lip 1.2 has elastically deformed in a certain area and has, so to speak, applied itself to the membrane 3, do the two lateral sealing lips 1.1, 1.3 also come into contact with the membrane 3.However, since the surface pressures between these two lateral sealing lips 1.1, 1.3 and the diaphragm 3 are significantly lower than the surface pressure between the central sealing lip 1.2 and the diaphragm 3, the main sealing effect also occurs in the central area. Therefore, the outer sealing lips 1.1, 1.3 primarily serve to stabilize the central sealing lip 1.2, creating a supporting force that flows primarily toward the central sealing lip 1.2.

[0032] If only a single sealing lip 2.1 were provided on the other side of the diaphragm 3 instead of the multiple sealing lips 2.1 arranged side by side, this design could ensure a sufficient sealing effect on both sides of the diaphragm 3. However, the components would have to be manufactured and assembled with very high precision, since the two sealing lips 1.2, 2.1, which are primarily responsible for the sealing effect, would then have to be positioned as precisely as possible opposite each other. Even a small offset could result in insufficient surface pressure between the sealing lips 1.2, 2.1 and the diaphragm 3 being ensured, thus resulting in insufficient sealing.

[0033] The multiple sealing lips 2.1 of the second sealing section 2 arranged side by side thus allow for tolerance compensation. This means that even if the two sheets 4.1, 4.2 and thus the sealing sections 1, 2 exhibit a certain offset, a sufficient sealing effect can still be achieved. This will be illustrated below with reference to the illustration of the Fig. 3a to 3d, which show the two sheets 4.1, 4.2 in slightly different positions. The membrane 3 arranged between the sealing sections 1, 2 is shown in the illustrations of Fig. 3a to 3c not shown.

[0034] The representation of the Fig. Figure 3a initially shows an optimal positioning of the two sheets 4.1, 4.2, in which the middle sealing lip 1.2 is located opposite the middle sealing lip 2.1 of the second sealing section 2. Furthermore, the sealing line D can be seen, which actually consists of two individual sealing lines D arranged on opposite sides of the membrane 3. For better visibility and because the membrane 3 is not shown, only one sealing line D is shown between the two opposing wave crests of the two sealing sections 1, 2.

[0035] The representation of the Fig. 3b now shows the two sheets 4.1, 4.2 in a different view than the illustration of the Fig. 3a offset arrangement. This offset can result, for example, from manufacturing or assembly inaccuracies. It can be seen that the middle sealing lip 1.2 of the first sealing section 1 is no longer opposite the middle sealing lip 2.1 of the second sealing section 2, but a sealing lip 2.1 that is arranged significantly further outwards. However, since the sealing lips 2.1 all have the same height, this has no influence on the sealing effect on both sides of the membrane 3, but rather, due to the multiple sealing lips 2.1 arranged next to one another, a reliable seal can be ensured even with a corresponding offset of the two sheets 4.1, 4.2 or the two sealing sections 1, 2. The positions shown in the illustrations of the Fig. 3a and Fig. 3b, but have in common that the middle sealing lip 1.2 is opposite a wave crest on the other side of the membrane 3, so that the force flow can flow in a straight line through the two opposite sealing lips 2.1, 1.2 and there is a sufficient contact force on both sides of the membrane 3.

[0036] The representation of the Fig. Figure 3c shows a configuration or positioning of the two sheets 4.1, 4.2, in which the middle sealing lip 1.2 is not opposite a wave crest, but rather a wave trough. This means that the force flow can no longer run in a straight line through the two sealing sections 1, 2, but rather the force flow is divided between the two wave crests, which are arranged next to the wave trough opposite the sealing lip 1.2. In this respect, two sealing lines D are also created on the side of the second sealing section 2, which are shown in the illustration of the Fig. 3c. Overall, the sealing effect is at its worst with this positioning of the sheets 4.1, 4.2, i.e. when the sealing lip 1.2 is opposite a wave trough. This is accompanied by the fact that on both sides of the membrane 3 only comparatively low contact pressures of the sealing sections 1, 2 are achieved and the membrane 3, due to its flexibility, is deformed slightly into the area of ​​the opposite wave trough by the middle sealing lip 1.2. However, the contact pressure and also the sealing lips 1.1, 1.2, 1.3, 2.1 are designed in such a way that even with the position shown in the illustration of the Fig. 3c, a sufficient sealing effect is still ensured and there is no medium flow across the sealing sections 1, 2.

[0037] As can be seen from the representation of the Fig.As can be seen in Figure 2, not only is a seal or sealing section 1, 2 provided between the membrane 3 and the two sheets 4.1, 4.2, but the sheets 4.1, 4.2 are also each provided with a sealing section 1, 2 on the side facing away from the membrane 3, via which the sheets 4.1, 4.2 are also sealed from the plates 5.1, 5.2 arranged further outwards. Thus, a medium can flow on both sides of the two sheets 4.1, 4.2.

[0038] Between the metal sheets 4.1, 4.2 and the plates 5.1, 5.2, first sealing sections 1 are provided, i.e., those consisting of three sealing lips 1.1, 1.2, 1.3, of which the central sealing lip 1.2 has a greater height than the two lateral sealing lips 1.1, 1.3. Due to the compressive force with which the individual layers of the fuel cell 20 are pressed against one another, the sealing lips 1.1, 1.2, 1.3 are pressed against the sides of the plates 5.1, 5.2 facing the metal sheets 4.1, 4.2, thereby achieving a reliable sealing effect. The sealing sections 1, 2 arranged on the sheets 4.1, 4.2, which face the membrane 3, are connected to the sealing sections 1, 2, which face the plates 5.1, 5.2, so that a relative movement between the sheets 4.1, 4.2 and the respective sealing sections 1, 2 is prevented.

[0039] Overall, the invention allows the various layers of a fuel cell 20 to be reliably sealed, even if deviations occur during production or assembly. LIST OF REFERENCE SYMBOLS 1. First sealing section 1.1 Sealing lip 1.2 Sealing lip 1.3 Sealing lip 2. Second sealing section 2.1 Sealing lip 3 membranes 4.1 Sheet metal 4.2 Sheet metal 5.1 Plate / Bipolar Plate 5.2 Plate / Bipolar Plate 10 Sealing device 20 fuel cells D Sealing line

Claims

[1] Sealing device for use in a fuel cell (20) with a first sealing section (1) and a second sealing section (2) which can be arranged on opposite sides of a membrane (3), in particular a subgasket, and which can prevent a medium flow along the membrane (3), characterized by that at least one of the two sealing sections (1, 2) has several sealing lips (2.1) arranged next to one another for tolerance compensation. [2] Sealing device according to claim 1, characterized by that the first sealing section (1) has an odd number of sealing lips (1.1, 1.2, 1.3), in particular three sealing lips (1.1, 1.2, 1.3). [3] Sealing device according to claim 2, characterized by that the sealing lips (1.1, 1.2, 1.3) of the first sealing section (1) have a different height. [4] Sealing device according to one of claims 2 or 3, characterized bythat the middle sealing lip (1.2) of the first sealing section (1) is higher than the other sealing lips (1.1, 1.3) of the first sealing section (1). [5] Sealing device according to one of claims 2 to 4, characterized by that the middle sealing lip (1.2) can be stabilized by the other sealing lips (1.1, 1.3). [6] Sealing device according to one of the preceding claims, characterized by that the second sealing section (2) has an odd number of sealing lips (2.1), wherein the number of sealing lips (2.1) of the second sealing section (2) is greater than the number of sealing lips (1.1, 1.2, 1.3) of the first sealing section (1). [7] Sealing device according to claim 6, characterized by that the sealing lips (2.1) of the second sealing section (2) have the same height. [8] Sealing device according to one of the preceding claims, characterized bythat one of the sealing lips (1.2) of the first sealing section (1), in particular the middle sealing lip (1.2), is opposite one of the sealing lips (2.1) of the second sealing section (2). [9] Sealing device according to one of claims 1 to 7, characterized by that one of the sealing lips (1.2) of the first sealing section (1), in particular the middle sealing lip (1.2), is opposite a wave trough arranged between two sealing lips (2.1) of the second sealing section (2). [10] Fuel cell with a membrane (3), in particular a subgasket, and a sealing device (10) according to one of the preceding claims. [11] Fuel cell according to claim 10, characterized by two sheets (4.1, 4.2) arranged in particular parallel to one another, wherein the first sealing section (1) is connected to the first sheet (4.1) and the second sealing section (2) is connected to the second sheet (4.2). [12] Fuel cell according to one of claims 10 or 11, characterized bythat first sealing sections (1) are arranged on both sides of the first sheet (4.1). [13] Fuel cell according to one of claims 10 to 12, characterized by that a first sealing section (1) is arranged on one side of the second sheet (4.2) and a second sealing section (2) is arranged on the opposite side. [14] Fuel cell according to one of claims 10 to 13, characterized by two plates (5.1, 5.2), in particular two bipolar plates, wherein the first and second sheets (4.1, 4.2) are sealed off from the plates (5.1, 5.2) on their side facing away from the membrane (3).

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