Framed membrane electrode assembly for fuel cell

Abstract

A framed membrane electrode assembly (1) for a fuel cell has a membrane electrode assembly (2), wherein the frame substrate (4) is arranged at least in an edge region of the membrane electrode assembly (2). The frame substrate (4) has at least one through-opening (6) which extends through the frame substrate (4) from an anode-side surface (4a) to a cathode-side surface (4b). A sealing assembly (3) made of a sealing material is arranged both on the anode-side and on the cathode-side surface of the frame substrate (4) and has in each case at least one sealing bead (30) which is connected both on the anode side and on the cathode side via at least one gate (7) to a cast-on part (5) made of the sealing material. The through-opening (6) is filled with the sealing material, and the cast-on part (5) overlaps with the through-opening (6), wherein the through-opening (6) has a greater extent than the cast-on part (5) at least in the direction of the at least one runner (7).

Description

[0001] Framed membrane electrode assembly for a fuel cell

[0002] The present invention relates to a framed membrane electrode assembly for a fuel cell and a method for producing a sealing assembly for a framed membrane electrode assembly.

[0003] Various fuel cell systems are known, for example, polymer electrolyte membrane (PEM) fuel cells, which use hydrogen as fuel. A fuel cell consists of electrodes, an anode, and a cathode, between which an electrolyte is located (the membrane electrode assembly (MEA). In a PEM fuel cell, the electrolyte is in the form of a membrane made of an ion-conducting polymer (so-called ionomer), the so-called polymer electrolyte membrane (PEM). Catalyst layers are applied to both sides of the PEM, forming a CCM (catalyst-coated membrane). A GDL (gas diffusion layer) is applied to each side of the CCM, ultimately forming an MEA. A frame or frame substrate typically reinforces the thin membrane (or MEA) and provides structural support and stability to the assembly.The MEA with the frame substrate, or framed MEA, is also called a MEFA (membrane electrode frame assembly). This frame helps keep the fuel cell components securely in place in a stack, enabling efficient operation and performance. The PEM separates the two electrodes materially and electrically, but allows a specific type of ion, in this case protons, to pass through. The protons migrate through the membrane to the cathode, while the electrons pass through an external circuit to generate electrical energy. At the cathode, the protons, electrons, and oxygen react to form water.

[0004] Since the electrical voltage of a single fuel cell is limited, several cells are connected in series to form a "stack" to achieve a correspondingly higher voltage. The individual MEFAs are separated from each other by bipolar plates, with the bipolar plates connecting the anodes and cathodes of consecutive MEFAs to form the series circuit. A bipolar plate is responsible for supplying hydrogen and oxygen, removing water, and cooling the fuel cell stack. Furthermore, the bipolar plate on the anode (hydrogen) side absorbs the hydrogen released from the hydrogen and then returns it to the cathode (oxygen) side.For proper operation of the fuel cell, a seal must be present between the MEFA and the bipolar plates adjacent to the MEFA to prevent mixing of the fluids within the fuel cell and also leakage of fluid from the fuel cell into the environment. A MEFA therefore has a corresponding sealing arrangement on both sides, i.e. the anode side and the cathode side, in particular surrounding the catalyst coatings and the connection openings. These seals, which are applied in particular to the frame substrate of the MEA, are applied in two steps or separately on both sides in conventional processes. However, this increases the cycle time for seal production, so that processes are also known for applying the seals on both sides in a single work step. This can be achieved, for example, using a suitable injection mold.However, problems can arise, such as uneven material flow during production, which can lead to uneven filling of the cavities in the injection mold and thus defects such as bubbles, defects and the like in the sealing arrangement.

[0005] The present invention is based on the object of providing a framed membrane electrode assembly (MEFA) with a sealing arrangement that can be manufactured quickly and reliably.

[0006] This object is achieved according to the teaching of the independent claims. Various embodiments and further developments of the invention are the subject of the dependent claims.

[0007] A first aspect of the invention relates to a framed membrane electrode assembly (MEFA) for a fuel cell. The MEFA comprises a membrane electrode assembly (MEA) with a frame substrate arranged at least in an edge region of the MEA. The frame substrate has at least one through-opening extending through the frame substrate from an anode-side surface to a cathode-side surface. The MEFA further comprises a sealing arrangement made of a sealing material, wherein the sealing arrangement is arranged on both the anode-side and the cathode-side surfaces of the frame substrate and has at least one sealing bead each, which is connected to a sprue made of the sealing material via at least one sprue web on both the anode side and the cathode side.The through-opening is filled with the sealing material, and the sprue part overlaps with the through-opening, wherein the through-opening has a greater extension than the sprue part, at least in the direction of the at least one sprue web.

[0008] A second aspect of the invention relates to a method for producing a sealing arrangement of a framed membrane electrode assembly for a fuel cell, in particular a framed membrane electrode assembly according to the first aspect. In the method, a membrane electrode assembly (MEA) is provided, wherein a frame substrate is arranged at least in an edge region of the MEA. The frame substrate has at least one through-opening which extends through the frame substrate from an anode-side surface to a cathode-side surface. The MEA with the frame substrate (i.e. the framed membrane electrode assembly; MEFA) is arranged between two half-shells of an injection mold with at least one injection opening, such that the injection opening is arranged in the region of the through-opening.The half-shells of the injection mold have cavities that define a sealing arrangement on both the anode-side and the cathode-side surfaces of the frame substrate, each with at least one sealing bead. These cavities are each connected to a sprue reservoir via at least one runner on both the anode side and the cathode side, the sprue reservoir overlapping the through-opening. A sealing material is then introduced into the injection mold through the injection opening, so that the through-opening and the sprue reservoir fill with the sealing material, and the sealing material is distributed via the sprue channels into the cavities of both half-shells. The through-opening has a greater extension than the sprue reservoir, at least in the direction of the at least one runner.

[0009] Alternatively, in the method according to the second aspect, a corresponding frame substrate for an MEA without the MEA can first be provided. The frame substrate (without the MEA) is then correspondingly arranged between the half-shells of the injection mold to produce the sealing arrangement in the same way. The MEA is then subsequently inserted into the frame substrate with the sealing arrangement to produce the MEA.

[0010] The sealing arrangement of the MEFA according to the first aspect can be manufactured in a single process step, in particular in a process according to the second aspect. This means, in particular, that the sealing arrangement can be manufactured on the cathode side and the anode side in a single step. This is made possible by the through-opening, which extends through the frame substrate. The manufacture of the sealing arrangement also creates a sprue part in the region of the through-opening, wherein the sprue part is connected to the actual sealing arrangement, in particular a sealing bead, via at least one sprue web. This creates a coherent structure made of the sealing material, which extends through the through-opening. Due to the size of the through-opening, the sealing material can be distributed there during production and can reach both sides of the frame substrate evenly.

[0011] The size of the through-hole is also particularly advantageous because it allows for inaccuracies (within certain tolerances) to be compensated for both during cutting or punching of the through-hole and during positioning of the MEFA in the injection mold. In particular, the larger extension of the through-hole in the direction of at least one sprue (or runner in the injection mold) ensures that the sealing material can reach the corresponding cavities of the injection mold via the sprues, which then appear as sprue in the finished MEFA, and which define the sealing arrangement. This means that the sprue reservoir and the sprue runners can be reliably positioned in the area of ​​the through-hole, ensuring a uniform material flow when introducing the sealing material.Since the sealing material is distributed in the large through-hole, flow differences between the two sides can be minimized.

[0012] The injection opening, which is located in one of the half-shells in the area of ​​the sprue reservoir, is located in the area of ​​the through-opening after the MEFA has been arranged in the injection mold. The injection opening can, in particular, be smaller than the through-opening. The sealing material is then distributed in the sprue reservoir and the through-opening and thus via the sprue channels in the cavities that define the sealing arrangement. The through-opening can, in particular, be closed all the way around, since the sealing material is introduced through the inlet opening in one of the half-shells in a direction transverse to the plane of the MEFA. In principle, lateral injection with a through-opening that is correspondingly open to the side would also be possible. However, this results in more complex flow conditions and the material distribution may not be as even.In some embodiments of the process, the sealing material is distributed simultaneously during insertion into the cavities of the two half-shells of the injection mold, both on the anode and cathode sides. The through-opening allows this production of the sealing arrangement on both sides in a single step. The sealing material is introduced or injected from only one side, allowing the sealing material to be distributed through the through-opening into both half-shells of the injection mold. By producing the sealing arrangement on both sides simultaneously, cycle times can be reduced.

[0013] The terms "sprue" and "sprue lands" used here refer specifically to structures resulting from the production of the sealing arrangement using the injection molding process. They consist of the sealing material of the sealing arrangement and can remain in the finished MEFA. However, they do not necessarily have a sealing function and could be removed if technically possible and sensible. The sprue can be viewed as a distributor, connected to the sealing arrangement via the sprue lands. The sprue and sprue lands are created by a "sprue reservoir" and "sprue channels" in the injection mold, which are advantageously located congruently in the half-shells of the injection mold. The sprue overlaps with the through-opening, which is also filled with the sealing material.The sealing material can, in particular, be an injection-moldable material that can harden after injection molding. The MEFA structures described here are, in particular, the result of manufacturing using a corresponding injection mold. Therefore, the (geometric) features of the structure are also described here with regard to the advantages associated with the corresponding manufacturing process.

[0014] The term "frame substrate" used here refers in particular to a support structure for the MEA. It is therefore arranged in particular in the edge regions of the MEA. It is understood that the frame substrate can in particular circumferentially surround a respective catalyst layer, which is applied to the PEM on the anode side and the cathode side, respectively. Furthermore, the frame substrate can surround corresponding connection openings. Likewise, the sealing arrangement can then circumferentially surround the catalyst layers and connections. The frame substrate can comprise a film-like material. The terms "comprises," "includes," "includes," "has," "has," "with," or any other variant thereof, as used herein, are intended to cover a non-exclusive inclusion.For example, a method or apparatus that includes or has a list of elements is not necessarily limited to those elements, but may include other elements that are not expressly listed or that are inherent in such method or apparatus.

[0015] Furthermore, unless explicitly stated to the contrary, "or" refers to an inclusive "or" and not an exclusive "or." For example, a condition A or B is satisfied by one of the following conditions: A is true (or present) and B is false (or absent), A is false (or absent) and B is true (or present), and both A and B are true (or present).

[0016] The terms "a" or "an" as used herein are defined as "one or more." The terms "another" and "another," and any other variations thereof, are defined as "at least one other."

[0017] The term “plurality” as used here shall mean “two or more”.

[0018] The term “configured” or “set up” to fulfil a specific function (and respective modifications thereof) is to be understood within the meaning of the invention that the corresponding device is already in a design or setting in which it can carry out the function or is at least adjustable - i.e. configurable - so that it can carry out the function after being set accordingly. The configuration can be carried out, for example, by appropriately setting parameters of a process sequence or of switches or the like for activating or deactivating functionalities or settings. In particular, the device can have a plurality of predetermined configurations or operating modes, so that the configuration can be carried out by selecting one of these configurations or operating modes.

[0019] Preferred embodiments are described below which, unless expressly excluded or technically impossible, can be combined with one another as desired and with the other aspects of the invention described. In some embodiments, the through-opening overlaps with the at least one sprue web. The at least one sprue web is thus connected not only to the sprue part, but also (directly) to the through-opening. This means that during production, the sealing material not only reaches the corresponding sprue channels from the sprue reservoir forming the sprue part, but also from the through-opening. This allows the sealing material to flow over a larger flow cross-section, which improves the introduction of the sealing material into the cavities for the sealing arrangement.

[0020] Accordingly, in some embodiments of the method, the through-opening is connected to the at least one runner when arranging the MEFA (or the frame substrate without the MEA) in the injection mold, so that the sealing material is distributed during injection from both the sprue reservoir and the through-opening via the at least one runner into the cavities. The improved flow cross-section into the runners allows for a uniform material flow, particularly to both sides simultaneously.

[0021] In some embodiments, the distance between the sealing bead and the sprue part is greater than the distance between the sealing bead and the through-opening. The distance between the sealing bead and the sprue part corresponds in particular to the length of the sprue land. This allows the sprue lands to overlap with the through-opening, as just described. A sufficiently long sprue lands (or sprue channels) also ensures that tolerances regarding the position of the through-opening in the frame substrate and the positioning of the MEFA in the injection mold can be better compensated, ensuring the desired flow of the sealing material during injection through the sprue channels.

[0022] In some embodiments, the at least one sprue bar extends between the sprue part and the sealing bead beyond an edge of the through-opening. This design also has the effects just described.

[0023] In some embodiments, the sprue part is connected to the respective sealing bead on both the anode side and the cathode side via more than one sprue land. For example, two, three or four, preferably three, sprue lands can be present. Consequently, a corresponding number of sprue channels are also present in an injection mold. By dividing the flow of the sealing material during injection into several channels, it can be ensured that if one channel becomes blocked, the sealing material can continue to flow via at least one other channel. In the case of three sprue lands or sprue channels per side (i.e., on the anode side and the cathode side), this is further improved. Four or more channels per side would also be conceivable. However, this would require more space or result in relatively small channel cross-sections for the same space requirement.

[0024] Accordingly, in some embodiments of the method, the sprue reservoir is connected to the respective cavity on both the anode and cathode sides of the two half-shells via more than one sprue channel each, so that the frame substrate is held by the injection mold between the sprues on both the anode and cathode sides. The sprues are preferably congruent in the two half-shells. By dividing the material flow across multiple channels, the process can be continued even if one channel becomes blocked. Furthermore, the frame substrate can be supported by the injection mold in the areas between the channels, so that bending during injection of the sealing material can be avoided or at least reduced.

[0025] In some corresponding embodiments, an area between the sprue lands, the sealing bead, and the through-hole is free of sealing material. This free space between the sprue lands means that this is where the injection mold contacts the frame substrate. With congruent structures on both sides, this can ensure that the frame substrate is clamped and thus supported by the injection mold. Especially with thin and correspondingly flexible substrates, this can prevent or reduce substrate deflection in the area of ​​the sprue channels. This allows the material flow to be distributed evenly between both sides.

[0026] In some corresponding embodiments with multiple sprue bars, these extend parallel to one another from the sprue part. A parallel arrangement can help ensure that the material flows evenly from the sprue reservoir through the sprue channels. In particular, the channels can also be of equal length.

[0027] In some embodiments, an edge of the through-opening facing the sealing bead has a straight section whose length is greater than the sum of the widths of all sprue lands and the spaces between them. This straight section can, in particular, be the area over which the sprue lands extend. Due to the length of the straight section, any inaccuracies regarding the position of the through-opening in the frame substrate and the positioning of the MEFA in the injection mold, in particular in a direction transverse to the sprue channels (i.e., along the straight section), can be compensated for. In this way, it can be ensured that no sprue channel is offset from the through-opening in extreme cases, which would impair the material flow during injection during production of the sealing arrangement.

[0028] In some embodiments, the sprue extends in at least one direction of extension, preferably transverse to the sprue webs or parallel to the sealing arrangement, beyond the through-opening, respectively, over the anode-side and cathode-side surfaces of the frame substrate. Since the sprue overlaps the through-opening and, moreover, encompasses the frame substrate on both sides, the sealing material can be held in the through-opening. If the sprue were smaller than the through-opening, the sealing material could protrude from the through-opening (together with the sprue) of the frame substrate. This would impair subsequent assembly of a fuel cell.

[0029] In some embodiments, the at least one sprue land is flatter than the sealing bead. As already mentioned above, the sprue land(s) are not designed to fulfill a sealing function, but are merely due to the manufacturing process. It is therefore advantageous to design the sprue lands flatter than the actual sealing arrangement so that during assembly only the sealing arrangement actually comes into contact and the sealing function is not impaired by the sprue lands. This can also reduce the risk of them causing interference during assembly. It goes without saying, however, that they are not designed to be too flat (or the sprue channels in the injection mold) so that the material flow is not impaired during production.

[0030] In some embodiments, the sprue part is flatter than the at least one sprue land. The sprue part occupies a certain area on the MEFA (overlapping with the through-opening). Therefore, it is advantageous to design the sprue part as flat as possible, also to prevent it from impairing the contact of the sealing arrangement during assembly of a fuel cell.

[0031] The features and advantages explained with reference to the first aspect of the invention also apply accordingly to the further aspects of the invention. In particular, the features and advantages described in connection with the MEFA according to the first aspect also apply to the method according to the second aspect. The MEFA according to the first aspect or a MEFA with a sealing arrangement produced according to a method according to the second aspect can be used in a fuel cell and in particular also in a fuel cell stack having at least one fuel cell with at least one such MEFA.

[0032] Further advantages, features and possible applications of the present invention will become apparent from the following detailed description in conjunction with the drawings.

[0033] It shows:

[0034] Fig. 1 is a perspective view of a portion of a framed membrane electrode assembly (MEFA);

[0035] Fig. 2 shows a section through the sealing arrangement of the MEFA from Fig. 1;

[0036] Fig. 3 a detailed view of the MEFA from Fig. 1 ;

[0037] Fig. 4 shows schematically a section through an injection mold for producing the sealing arrangement for the MEFA from Fig. 1;

[0038] Fig. 5 shows a section through an arrangement of the MEFA from Fig. 1 between two bipolar plates;

[0039] Fig. 6 is an enlarged view of Fig. 3 with different section lines;

[0040] Fig. 7 shows a section through the MEFA from Fig. 6;

[0041] Fig. 8 shows a section through the MEFA from Fig. 6; Fig. 9 shows a section through the MEFA from Fig. 6; and

[0042] Fig. Small section through the MEFA from Fig. 6.

[0043] Throughout the figures, the same reference numerals are used for the same or corresponding elements of the invention. The figures are schematic and therefore do not necessarily represent the actual objects to scale.

[0044] Fig. 1 shows a plan view of part of a framed membrane electrode assembly (MEFA) 1 for a fuel cell. The MEFA 1 comprises a membrane electrode assembly (MEA) 2, which is held by a frame substrate 4 and has a membrane, in particular a polymer electrolyte membrane (PEM), coated with electrodes on both sides. This structure enables the chemical reactions and electron transfer necessary for converting fuel into electricity in a fuel cell.

[0045] The MEFA 1 is arranged between two bipolar plates 20 (see Fig. 5), thereby forming a fuel cell of a fuel cell stack. A sealing arrangement 3 is provided on both sides of the MEFA 1 (i.e., the anode side and the cathode side) to seal off the bipolar plates 20. The sealing arrangement 3 is generally applied around the periphery of the MEFA 1 on the frame substrate 4, i.e., in an edge region of the MEFA 1, to ensure sealing between the individual components of the fuel cell stack and prevent the penetration of gases or liquids. This ensures reliable function of the fuel cell.

[0046] Fig. 2 shows the sealing arrangement 3 in section along line II. The sealing arrangement 3 has at least one sealing bead 30, as shown by way of example in Fig. 2. Alternative designs of the sealing arrangement, for example, with two parallel sealing beads, are also conceivable. The sealing arrangement 3 is manufactured using an injection molding process. As a result, sprue parts 5 are present, one of which is shown enlarged in Fig. 3 (section III).

[0047] Fig. 4 schematically illustrates the production of the sealing arrangement 3 using the injection molding process. For this purpose, the MEA 2 with the frame substrate 4 is arranged between two half-shells 11, 12 of an injection mold 10. The sealing arrangement 3 is defined by cavities 15 in the two half-shells 11, 12, i.e. the sealing beads 30 of the sealing arrangement 3 are formed on both sides of the frame substrate 4. Sealing material is introduced into the injection mold 10 through an injection opening 9 and is initially distributed in a sprue reservoir 13 and a through-opening 6 in the frame substrate 4. The sealing material reaches both sides of the frame substrate 4 through the through-opening 6, where it then flows through sprue channels 14 into the cavities 15 to form the sealing arrangement 3. The sealing assemblies 3 can thus be formed on both sides in one step.After injection molding, in particular after the sealing material has cured, sealing material also remains in the through-opening 6 as well as in the sprue reservoir 13 and the sprue channels 14. This creates a sprue part 5 and sprue webs 7. Alternatively, the (pre-cut) frame substrate 4 can initially be arranged without the MEA 2 between the half-shells 11, 12 of the injection mold 10, wherein the sealing arrangement 3 is then formed on the frame substrate 4 in the same way. The MEA 2 is then introduced into the frame substrate 4 after the sealing arrangement 3 has been formed.

[0048] With particular reference to Fig. 6, the geometry of a sprue 5 and adjacent structures will now be described in further detail. Fig. 7, Fig. 8, Fig. 9, and Fig. 10 are corresponding sectional views along lines VII, VIII, IX, and X, respectively.

[0049] The through-opening 6 is larger than the sprue part 5, in particular the through-opening 6 has a greater extension in the direction of the sprue webs 7 than the sprue part 5. As a result, the sprue webs 7 (or the sprue channels 14) overlap with the through-opening 6. The sprue webs 7 (or the sprue channels 14) also have a sufficient length (e.g., approximately 1 mm) so that they extend beyond the edge 6a of the through-opening 6. In this way, tolerances with regard to the position of the through-opening 6 in the frame substrate 4 and also tolerances with regard to the positioning of the MEA 2 with the frame substrate 4 in the injection mold 10 can be compensated, so that a uniform material flow (cf. arrows in Fig. 4 and Fig. 7) on both sides can be achieved.The large dimensions of the through opening 6 also ensure an improved distribution of the material flow to both sides and thus minimal flow differences between the two sides.

[0050] In this exemplary embodiment, three sprue lands 7 (or sprue channels 14) are also provided on each side, so that the material flow from the through-opening 6 and the sprue reservoir 13 is distributed among these multiple sprue channels 14. This creates redundancy so that the sealing arrangement 3 can be successfully formed even if one of the channels 14 is blocked. Furthermore, the injection mold 10 supports the frame substrate 4 in the free spaces 8 between the sprue lands 7 (or sprue channels 14) during injection of the sealing material, thus preventing bending of the frame substrate 4, which could lead to an uneven distribution of the sealing material between the two sides or even to a blockage of one of the sides.More than one channel 14 with sufficient channel depth on each side of the frame substrate 14 reduces the likelihood of small deviations that can occur with unsupported substrates, during machining of tool channels, burrs / bends on the frame edges, etc. The clearances 8 can, for example, have a width of at least about 0.25 mm to provide a sufficient support surface. The sprue lands 7 are flatter than the sealing beads 30 of the sealing arrangement 3 to avoid contact with the adjacent bipolar plates 20 (see Fig. 5). The sprue part 5 is even flatter for the same reason.

[0051] As can be seen in Fig. 10, the sprue part 5 extends in a direction transverse to the sprue webs 7 beyond the through-opening 6 onto the surfaces 4a, 4b and thus encompasses the frame substrate 4. In this way, the sprue part 5 and the sealing material are held in place in the through-opening.

[0052] While at least one exemplary embodiment has been described above, it should be noted that a large number of variations exist. It should also be noted that the described exemplary embodiments are only non-limiting examples and are not intended to limit the scope, applicability, or configuration of the devices and methods described herein. Rather, the foregoing description will provide a guide to implementing at least one exemplary embodiment, with the understanding that various changes in the operation and arrangement of the elements described in an exemplary embodiment may be made without departing from the subject matter defined in the appended claims, as well as their legal equivalents.

[0053] 1 framed membrane electrode assembly (MEFA)

[0054] 2 membrane electrode assembly (MEA)

[0055] 3 Sealing arrangement 4 Frame substrate

[0056] 5 sprue part

[0057] 6 passage opening

[0058] 6a Edge of the passage opening

[0059] 7 Gate 8 Clearance

[0060] 9 Injection opening

[0061] 10 Injection mold

[0062] 11 , 12 Half shells of the injection mold

[0063] 13 sprue reservoir 14 sprue channel

[0064] 15 Cavity

[0065] 20 bipolar plate

[0066] 30 sealing bead

Claims

CLAIMS 1 . Framed membrane electrode assembly (1) for a fuel cell, comprising: a membrane electrode assembly (2) with a frame substrate (4) which is arranged at least in an edge region of the membrane electrode assembly (2), wherein the frame substrate (4) has at least one through-opening (6) which extends through the frame substrate (4) from an anode-side surface (4a) to a cathode-side surface (4b); and a sealing arrangement (3) made of a sealing material, wherein the sealing arrangement (3) is arranged on both the anode-side and the cathode-side surface of the frame substrate (4) and has at least one sealing bead (30) which is connected to a sprue part (5) made of the sealing material on both the anode side and the cathode side via at least one sprue web (7), wherein the through-opening (6) is filled with the sealing material and the sprue part (5) overlaps with the through-opening (6), wherein the through-opening (6) is open at least in the direction of the at least one sprue web (7) has a greater extension than the sprue part (5).

2. Framed membrane electrode assembly according to claim 1, wherein the through opening (6) overlaps with the at least one sprue web (7).

3. Framed membrane electrode assembly according to claim 1 or 2, wherein a distance between the sealing bead (30) and the sprue part (5) is greater than a distance between the sealing bead (30) and the through opening (6).

4. Framed membrane electrode assembly according to one of the preceding claims, wherein the at least one sprue web (7) extends between the sprue part (5) and the sealing bead (30) over an edge of the through-opening (6).

5. Framed membrane electrode assembly according to one of the preceding claims, wherein the sprue part (5) is connected to the respective sealing bead (30) on both the anode side and the cathode side via more than one sprue web (7).

6. Framed membrane electrode assembly according to claim 5, wherein a free space (8) between the sprue webs (7), the sealing bead (30) and the through opening (6) is free of the sealing material.

7. Framed membrane electrode assembly according to 5 or 6, wherein the gate webs (7) extend parallel to one another from the gate part (5).

8. Framed membrane electrode assembly according to one of claims 5 to 7, wherein an edge of the through-opening (6) facing the sealing bead (30) has a straight section (6a) whose length is greater than the sum of the widths of all the sprue webs (7) and their intermediate spaces (8).

9. Framed membrane electrode assembly according to one of the preceding claims, wherein the sprue part (5) extends in at least one direction of extension beyond the through opening (6) in each case over the anode-side and cathode-side surfaces (4a, 4b) of the frame substrate (4).

10. Framed membrane electrode assembly according to one of the preceding Claims, wherein the at least one sprue web (7) is flatter than the sealing bead (30).

11. Framed membrane electrode assembly according to one of the preceding Claims, wherein the sprue part (5) is flatter than the at least one sprue web (7).

12. Method for producing a sealing arrangement (3) of a framed Membrane electrode assembly (1) for a fuel cell, in particular a framed membrane electrode assembly (1) according to one of the preceding claims, wherein the method comprises: Providing a frame substrate (4) for a membrane electrode assembly (2) or a membrane electrode assembly (2) with a frame substrate (4) which is arranged at least in an edge region of the membrane electrode assembly (2), wherein the frame substrate (4) has at least one through-opening (6) which extends through the frame substrate (4) from an anode-side surface (4a) to a cathode-side surface (4b); Arranging the frame substrate (4) or the membrane electrode arrangement (2) with the frame substrate (4) between two half-shells (11, 12) of an injection mold (10) with at least one injection opening (9), so that the Injection opening (9) is arranged in the region of the through-opening (6), wherein the half-shells (11, 12) of the injection mold (10) have cavities (15) which define a sealing arrangement (3) on both the anode-side and the cathode-side surface (4a, 4b) of the frame substrate (4), each with at least one sealing bead (30) and are each connected to a sprue reservoir (13) via at least one sprue channel (14) on both the anode side and the cathode side, wherein the sprue reservoir (13) overlaps with the through-opening (6); Introducing a sealing material through the injection opening (9) into the injection mold (10) so that the through-opening (6) and the sprue reservoir (13) are filled with the sealing material and the sealing material is distributed via the sprue channels (14) in the cavities (15) of both half-shells (11, 12), wherein the through-opening (6) has a greater extent than the sprue reservoir (13), at least in the direction of the at least one sprue channel (14).

13. The method according to claim 12, wherein the sealing material is distributed simultaneously on the anode side and the cathode side during introduction into the cavities (15) of the two half-shells (11, 12) of the injection mold (10).

14. The method according to claim 12 or 13, wherein the through-opening (6) is brought into contact with the at least one sprue channel (14) when the frame substrate (4) or the membrane electrode assembly (2) is arranged with the frame substrate (4) in the injection mold (10), so that the sealing material is distributed during injection both from the sprue reservoir (13) and from the through-opening (6) via the at least one sprue channel (14) in the cavities (15).

15. The method according to any one of claims 12 to 14, wherein the sprue reservoir (13) is connected to the respective cavity (15) via more than one sprue channel (14) in each of the two half-shells (11, 12) on both the anode side and the cathode side, the sprue channels (4) in the two half-shells being congruent, so that the frame substrate (4) is held by the injection mold (10) between the sprue channels (14) on both the anode side and the cathode side.

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