DE102020207919A1 - Fuel cell assembly and method for manufacturing a fuel cell assembly - Google Patents

Abstract

The invention relates to a fuel cell arrangement (10) with fuel cells (20) arranged stacked in a stacking direction (z), each of which is plate-shaped and extends in first and second transverse directions (x, y) when viewed orthogonally to the stacking direction (z), and each having stacked in the stacking direction (z): an anode side bipolar half plate (22) having a fuel channel structure (24) for guiding a fuel; an anode-side gas diffusion layer (26); a membrane-electrode unit (28) comprising an electrolyte membrane (30) and electrode layers (32, 34) arranged on either side thereof, which form an anode (32) and a cathode (34) for an electrochemical reaction of the fuel with an oxidizing agent; a cathode-side gas diffusion layer (36); a cathode-side bipolar half-plate (38) having an oxidant channel structure (40) for carrying the oxidant. According to the invention, the bipolar half-plates (22, 38) are shaped on a lateral edge area in such a way that they rest against one another in places on this lateral edge area or at least protrude close to one another in such a way that on a corresponding lateral edge area of the fuel cell arrangement (10) a stacking direction (e.g ) continuously extending cavity (49) is formed, this cavity (49) being filled with a sealing material (50).

Description

The present invention relates to a fuel cell arrangement according to the preamble of claim 1 and a method for producing a fuel cell arrangement according to the preamble of claim 9.

Such a fuel cell arrangement is also referred to as a fuel cell stack in the prior art and has fuel cells stacked in a stacking direction, each of which is plate-shaped and, viewed orthogonally to the stacking direction, extends in a first transverse direction and a second transverse direction orthogonal thereto.

• - eine anodenseitige Bipolar-Halbplatte mit einer Brennstoff-Kanalstruktur zur Führung eines Brennstoffes,
• - eine anodenseitige Gasdiffusionslage,
• - eine Membran-Elektroden-Einheit, aufweisend eine Elektrolytmembran und in Stapelrichtung beiderseits davon angeordnete Elektrodenschichten, die eine Anode und eine Kathode für eine elektrochemische Reaktion des Brennstoffes mit einem Oxidationsmittel ausbilden,
• - eine kathodenseitige Gasdiffusionslage,
• - eine kathodenseitige Bipolar-Halbplatte mit einer Oxidationsmittel-Kanalstruktur zur Führung des Oxidationsmittels.

The individual fuel cells each have, stacked in the stacking direction:

• - an anode-side bipolar half-plate with a fuel channel structure for guiding a fuel,
• - a gas diffusion layer on the anode side,
• - A membrane-electrode unit, comprising an electrolyte membrane and electrode layers arranged on both sides thereof in the stacking direction, which form an anode and a cathode for an electrochemical reaction of the fuel with an oxidizing agent,
• - a cathode-side gas diffusion layer,
• - A cathode-side bipolar half-plate with an oxidizing agent channel structure for guiding the oxidizing agent.

For the state of the art of such fuel cell stacks, refer to the publications as an example EP 2 357 698 B1 , EP 2 445 045 B1 , EP 2 584 635 B1 , EP 2 946 431 B1 and EP 3 316 377 A1 referenced.

With a fuel cell arrangement, the chemical reaction energy of a continuously supplied fuel (e.g. hydrogen) and a continuously supplied oxidizing agent (e.g. oxygen or air) can be converted into electrical energy by means of an electrochemical reaction.

During operation of the fuel cells arranged in an electrical series connection via the (electrically conductive) bipolar half-plates, the reactants of the electrochemical reaction, i.e. the fuel (e.g. hydrogen) and the oxidizing agent (e.g. air), must be different when viewed in the stacking direction Sides of the membrane-electrode assembly are fed within each fuel cell.

For this purpose, the bipolar half-plates of each fuel cell are each designed with the above-mentioned channel structure on their sides facing the membrane-electrode unit in order to transfer the fuel and the oxidizing agent on the respective sides of the membrane-electrode unit via these channel structures into the there to introduce adjacent respective gas diffusion layer and thus to bring it up to the respective electrode layer on the corresponding side of the electrolyte membrane via the respective gas diffusion layer.

The electrode layers are usually formed from a carbon material and coated or interspersed with a suitable catalyst. The electrode layer on the fuel side forms an anode and the electrode layer on the oxidizing agent side forms a cathode of the membrane-electrode unit.

The product of the electrochemical reaction taking place in the individual fuel cells, for example water, can be discharged via the fuel cell area carrying the oxidizing agent (for example air).

In the individual fuel cells, the fuel-carrying area, i.e. the anode-side channel structure, gas diffusion layer, electrode layer (anode), and the oxidizing agent-carrying area, ie cathode-side channel structure, gas diffusion layer, electrode layer (cathode), must be sealed off from one another in order to prevent gas exchange that is detrimental to power efficiency to prevent between these areas.

This implies in particular that at least one of the two areas must be sealed off from the surroundings of the fuel cell or the fuel cell stack (e.g. atmosphere) in order to prevent such an exchange via the surroundings. In practice, at least the fuel-carrying area is sealed off from the environment in order to prevent a loss of fuel from this fuel cell area into the environment and an entry of a medium (e.g. air) from the environment into this fuel cell area.

In particular, to form an air-cooled fuel cell arrangement, the oxidizing agent-carrying area can also be configured “open” to the environment. For example, the oxidizing agent channel structure provided in the individual fuel cells can be open on two opposite sides of the fuel cell when viewed in a transverse direction in order to enable the oxidizing agent (e.g. air) to flow in this transverse direction through the fuel cell arrangement during operation. For this it can Oxidizing agent e.g. B. be driven through the laterally open fuel cell assembly with a fan and at the same time ensure cooling.

In many cases, however, it is more advantageous if both the fuel-conducting area and the oxidizing agent-conducting area of the fuel cell stack are sealed off from one another and from the environment.

Common for such seals are z. B. separately manufactured and inserted between the bipolar plate and membrane-electrode unit seals, or z. B. a dispensing / spraying of sealing material on the respective components of the fuel cells (z. B. bipolar plate, membrane-electrode unit) during an assembly process, or a prefabrication of components of the fuel cells with already molded seals.

If the bipolar half-plates located there are spaced apart from one another at the transitions between fuel cells that are adjacent to one another in the stacking direction and a cooling medium (e.g. air or water) is guided in the intermediate spaces in order to cool the fuel cell arrangement in this way, it is required Furthermore, each bipolar plate has a further seal (or, for example, welding of bipolar half-plates) all around, on a lateral edge area of the fuel cell arrangement, usually even viewed in a circumferential direction of the fuel cell arrangement, in order to prevent the escape of cooling medium.

In the prior art, all seals of the type explained above disadvantageously require a relatively large amount of effort.

It is therefore an object of the present invention to show a novel way in a fuel cell arrangement of the type mentioned at the beginning or in its production, with which seals with regard to the desired guidance of fuel and / or oxidizing agent and / or optionally cooling medium provided separately therefrom in can be realized in a simple manner.

According to the invention, this object is achieved according to a first aspect by a fuel cell arrangement according to claim 1. The dependent claims relate to advantageous developments of the invention.

The fuel cell arrangement according to the invention is characterized in that the bipolar half-plates are designed on a lateral edge area in such a way that the bipolar half-plates abut one another in places at this lateral edge area or at least protrude close to one another that one in the stacking direction continuously extending cavity is formed, and that this cavity is filled with a sealing material.

The fact that the cavity extends “continuously in the stacking direction” is intended to mean that there are paths within the cavity at the lateral edge area of the fuel cell arrangement that go from a first (e.g., “lowermost”) fuel cell in the stacking direction to one in the stacking direction last (e.g. "top") fuel cell. In the area of the transitions between adjacent fuel cells viewed in the stacking direction, sections of the cavity can in this case, in particular, e.g. B. viewed in the stacking direction through openings going through the two bipolar half-plates located there, which thus connect the areas of the cavity below and above the respective transition area with one another.

With the invention, for example, fewer individual components can advantageously be brought together (in stacks) in the production of the fuel cell arrangement, since the cavity filled with the sealing material provided in the invention, depending on the specific configuration, e.g. B. able to replace the previously usual inserted seals. In addition, the cavity filled with the sealing material can also make the seals previously applied or molded onto certain components of the fuel cells (e.g. bipolar plate, membrane-electrode unit) unnecessary.

As a result, fewer tolerances usually have to be taken into account and the assembly time for producing the fuel cell arrangement can advantageously be reduced.

By filling the cavity with the sealing material, the seal can advantageously be introduced in a single process step. The mentioned "resting against one another" or "protruding close to one another" of the bipolar half-plates realizes a limitation of the cavity at the relevant points, i.e. at these points the sealing material cannot escape during filling. In practice (but also depending, for example, on the viscosity of the sealing material during filling), it can be "close to each other" (in the stacking direction), for example. B. be given that a remaining minimum gap width is less than 0.1 mm, in particular less than 0.05 mm.

Another advantage of the invention can result from configurations in which the electrochemically active ones are mechanically braced with the aid of the cavity filled with sealing material Areas or areas (e.g. membrane electrode units, gas diffusion layers) are no longer necessarily coupled with mechanical bracing of sealing layers in the fuel cell stack, as in the prior art. So z. B. a more uniform force distribution in the active areas advantageously increase the power density of the fuel cell arrangement.

The individual fuel cells preferably each have a plate-like shape with an at least approximately rectangular contour, so that a corresponding roughly cuboid fuel cell stack results.

In one embodiment, the fuel cells of the fuel cell arrangement are designed to be suitable for operation with hydrogen as the fuel, e.g. B. with an electrolyte membrane designed as a proton conducting membrane.

Alternatively, however, also z. B. a design of the fuel cell assembly for operation with a different fuel such. B. an organic compound (z. B. methane or methanol) or z. B. natural gas into consideration.

In one embodiment, the fuel cell arrangement is designed to be suitable for operation with air as the oxidizing agent.

In one use of the fuel cell arrangement, operation with pressure charging of the fuel cell stack with the oxidizing agent can be provided, in which the oxidizing agent is supplied under a pressure (supply pressure) that is higher than that of ambient atmospheric pressure on an inlet side for the oxidizing agent. The inlet pressure can e.g. B. greater than 1.2 bar, in particular greater than 1.5 bar. On the other hand, an inlet pressure of less than 5 bar, in particular less than 4 bar, is usually sufficient.

In one embodiment of a use of the fuel cell arrangement, the oxidizing agent is discharged at an outlet side at which a negative pressure prevails which is below atmospheric ambient pressure. The outlet pressure can e.g. B. less than 0.8 bar, in particular less than 0.6 bar. On the other hand, an outlet pressure of at least 0.1 bar is usually advantageous.

The channel structures of the individual fuel cells provided in the context of the invention can each have several, e.g. B. more than 10, or z. B. have more than 50, parallel channels. Each of the channel structures can e.g. B. in particular each have rectilinear and parallel channels. In one embodiment, straight channels of the fuel channel structures and the oxidizing agent channel structures run in a common (same) direction orthogonal to the stacking direction of the fuel cell arrangement. In another embodiment, such straight channels, on the one hand, of the fuel channel structures and, on the other hand, of the oxidizing agent channel structures, run in different directions orthogonal to the stacking direction. In particular, these different directions of the channels can be provided oriented orthogonally to one another.

As an alternative to rectilinear channels, more complicated courses of the respective channels can in principle also be provided for the fuel channel structures and / or the oxidizing agent channel structures, such as, for. B. Gradients containing bends and / or curvatures, z. B. meandering courses in the "fuel cell plane" spanned by the first and second transverse directions.

The channels of the channel structures can, for. B. have a rectangular or rounded-rectangular cross-section and can, for. B. have been formed by milling, punching, embossing or etching in the course of manufacturing the bipolar half-plates or bipolar plates.

In one embodiment, the bipolar half-plates are formed from a metallic material. Alternatively, the bipolar half-plates can in particular, for. B. of a carbon material or z. B. be formed from an electrically conductive plastic material (z. B. appropriately doped, z. B. With carbon black), or from another electrically conductive material.

According to one embodiment, the bipolar half-plates provided in the invention are each prefabricated separately from one another and inserted into the stack during the production of the fuel cell arrangement by stacking the individual components.

Mostly preferred is an embodiment in which the bipolar half-plates for the interior of the fuel cell stack are each prefabricated separately from one another, but have been connected to one another in pairs before they are inserted into the fuel cell assembly, e.g. B. by gluing or welding, so that bipolar plates are used in the manufacture of the fuel cell stack (which are each composed of two bipolar half-plates). In this embodiment, too, individual bipolar half-plates (“end plates”) can be arranged at the two ends viewed in the stacking direction.

In the interior of the fuel cell stack, the individual fuel cells can have an outside (ie the side facing away from the channel structure) of the anode-side bipolar half-plate z. B. directly on an outside (ie facing away from the channel structure) of the cathode-side bipolar half-plate of an adjacent (adjacent) fuel cell in the stacking direction, or the outside of the cathode-side bipolar half-plate of a fuel cell directly on the outside of the anode-side bipolar half-plate of an adjacent fuel cell apply, be it with or without a fixed connection such as B. Bonding, welding, etc.

In one embodiment of the fuel cell arrangement, it is provided that at each such transition between fuel cells the bipolar half-plates located there lie directly against one another in their central area (and without a large gap).

In another embodiment of the fuel cell arrangement, it is provided that the bipolar half-plates located there are spaced apart from one another in their central region at each transition between fuel cells that are adjacent to one another in the stacking direction. In the space thus present, during operation of the fuel cell arrangement, for. B. a cooling medium (z. B. air or water) to cool the fuel cell with it. Here, in the space z. B. another channel structure ("cooling medium channel structure") for guiding a cooling medium such. B. be designed cooling water.

In one embodiment, the gas diffusion layers are formed from a carbon fleece. Alternatively, depending on the intended fuel and oxidizing agent, other materials can also be considered.

In one embodiment, the anode and cathode forming electrode layers of the membrane-electrode unit of the fuel cells with a catalyst such as in particular z. B. coated or interspersed with a material containing platinum or palladium.

In one embodiment, a so-called sub-seal is provided on a lateral edge region (in particular at least on the lateral edge) of the membrane-electrode unit. The sub-gasket is a arranged there on both sides of the membrane-electrode unit and z. B. the side edge of the membrane-electrode unit enclosing (encompassing) sealing surface ready. The subgasket can, for. B. already formed in the manufacture of the membrane-electrode unit as part of the same, z. B. have been molded. Alternatively, sub-seals can e.g. B. are manufactured separately and inserted in the manufacture of the fuel cell assembly at the relevant points.

In one embodiment it is provided that the membrane-electrode unit (or at least the electrolyte membrane of the membrane-electrode unit) protrudes laterally over the side edges of the adjacent gas diffusion layers on the side edge area of the fuel cells.

In one embodiment of the invention it is provided that the cavity extends all around, viewed in a circumferential direction of the fuel cell arrangement. This is intended to mean that in the area of each fuel cell there is at least one annularly closed path within the cavity and running completely around the circumference of the fuel cell stack.

In one embodiment of the invention, it is provided that an outer wall of the cavity, viewed in the lateral direction, is formed by lateral edges of the bipolar half-plates resting against one another.

This embodiment relating to the formation of an outer wall of the cavity is unproblematic in the area of a transition between adjacent fuel cells insofar as two bipolar half-plates face each other in this area, which are at the same electrical potential when the fuel cell arrangement is in operation.

However, if this embodiment is used to form an outer wall of the cavity in the area of a fuel cell, the two opposing bipolar half-plates are at different electrical potentials when the fuel cell arrangement is in operation. In this case, electrical insulation can be provided at least in one contact area (contact surface between the bipolar half-plates), which z. B. can be accomplished by an electrically insulating coating on at least one of the two bipolar half-plates (or z. B. by an insulation layer inserted there).

In a modified embodiment, it is provided that an outer wall of the cavity, viewed in the lateral direction, is formed by lateral edges of the bipolar half-plates projecting close to one another (e.g. with a gap width of less than 0.1 mm).

This modified embodiment can be used to form an outer wall of the cavity both in the area of a fuel cell and in the area of a transition between adjacent fuel cells. When the cavity is filled, (electrically insulating) sealing material penetrate into a gap located in the relevant area between the lateral edges of the bipolar half-plates.

In a further development of the above embodiments relating to the formation of an outer wall of the cavity in the area of a fuel cell, it is provided that in each fuel cell the side edge of the anode-side bipolar half-plate and / or the side edge of the cathode-side bipolar half-plate is one in the stacking direction (and to the each other bipolar half-plate towards) has protruding projection.

A projection formed on the lateral edge of one of the two bipolar half-plates then rests against the lateral edge of the other bipolar plate formed without a projection (or protrudes close to it), or the projection rests on the lateral edge of one of the two bipolar half-plates a projection formed on the lateral edge of the other bipolar plate (or protrudes close to it).

In this way, a distance that otherwise exists within each fuel cell between the lateral edges of the two bipolar half-plates viewed in the stacking direction can be bridged and the cavity wall that laterally delimits outward can be formed. In a more specific embodiment, both the side edge of the anode-side bipolar half-plate and the side edge of the cathode-side bipolar half-plate have such a projection, these projections viewed in the stacking direction z. B. can be dimensioned at least approximately the same height (and thus, viewed in the stacking direction, each end approximately in the middle of the fuel cell).

This further development relating to the formation of an outer wall of the cavity in the area of a fuel cell can also be used in an analogous manner for the area of a transition between adjacent fuel cells, i.e. in this area it can also be provided that the lateral edge of the anode-side bipolar half-plate ( a fuel cell) and / or the lateral edge of the cathode-side bipolar half-plate (of an adjacent fuel cell) has a projection protruding in the stacking direction and towards the respective other bipolar half-plate.

In one embodiment of the invention it is provided that an inner wall of the cavity, viewed in the lateral direction, is formed in the area of each fuel cell by intermediate areas of the bipolar half-plates, which are each on one of the two sides (anode side or cathode side) of a side edge area (in particular e.g. B. the side edge) of the membrane-electrode assembly. In particular, the intermediate areas of the bipolar half-plates z. B. each rest on one of the two sides of a sub-gasket (and possibly compress it a little), which is arranged on the lateral edge area or edge of the membrane-electrode unit, z. B. integrally formed engages around the side edge, or z. B. consists of two parts, which are each arranged on one of the two sides of the lateral edge region or edge.

The “intermediate area” of a bipolar half-plate is to be understood as an area which (viewed in the lateral direction) lies between the lateral edge and a central area of the relevant bipolar half-plate.

In a further development of this embodiment it is provided that in the fuel cell the intermediate area of the anode-side bipolar half-plate and / or the intermediate area of the cathode-side bipolar half-plate has a protrusion protruding in the stacking direction (and towards the respective other bipolar half-plate).

In this way, otherwise existing gaps between the two bipolar half-plates on the one hand and the two sides (on the anode side and cathode side) of the lateral edge of the membrane-electrode unit can be bridged within each fuel cell, viewed in the stacking direction. The or the projections can thus, for. B. together with the lateral edge of the membrane-electrode unit form the wall of the cavity that delimits the side inwardly. In a preferred embodiment, both the intermediate area of the anode-side bipolar half-plate and the intermediate area of the cathode-side bipolar half-plate have such a projection, these projections, viewed in the stacking direction, preferably being at least approximately the same size. The “close to one another” of the bipolar half-plates then takes place except for a mutual distance which corresponds to the thickness of the membrane-electrode unit measured in the stacking direction at the point at which the ends of the projections rest on it.

In one embodiment of the invention it is provided that an inner wall of the cavity, viewed in the lateral direction, is formed in the region of a transition between (viewed in the stacking direction) adjacent fuel cells by intermediate regions of the bipolar half-plates that rest against one another or at least protrude close to one another.

As already mentioned, the bipolar half-plates located there (or at least their middle areas) can be used at the transitions between fuel cells that are adjacent to one another in the stacking direction. be spaced apart from one another when viewed in the stacking direction, in particular in order to guide a cooling medium in the area of these transitions between the fuel cells.

In this case, in particular, it can be provided that in each of these transition areas the intermediate area of at least one of the two bipolar half-plates has a protrusion protruding in the stacking direction and towards the other bipolar half-plate in order to bridge the gap and form the inner wall of the cavity.

In one embodiment of the invention, the seal realized by the sealing material located in the cavity is formed from an elastic plastic material which, during the manufacture of the fuel cell assembly, is in a flowable, ie z. B. liquid to viscous state was filled into the cavity and then cured (in a preferably permanently elastic state).

In one embodiment the sealing material is a polymer material such as e.g. B. a silicone material. Also z. B. a rubber material (z. B. FKM) or z. B. an epoxy material such. B. Propylene oxide (PO) can be used as a sealing material. After filling the cavity with flowable sealing material this can, for. B. thermally and / or (z. B. formed as a multi-component material) chemically cured to a desired degree of hardness, z. B. be networked.

In one embodiment, the fuel cell arrangement furthermore has a housing which at least partially surrounds the stacked fuel cells together with the seal formed in the lateral edge region. The housing can e.g. B. represent or have a frame structure by means of which the stacked arrangement of the fuel cells is fixed and, if necessary, braced (for example, pressure-loaded in the stacking direction). The housing can e.g. B. be composed of several housing parts that were positioned and connected to one another during the manufacture (assembly) of the fuel cell assembly.

• - Bilden einer Brennstoffzellenanordnung durch stapelndes Anordnen von Brennstoffzellen in einer Stapelrichtung, die jeweils plattenförmig ausgebildet sind und sich orthogonal zur Stapelrichtung betrachtet jeweils in einer ersten Querrichtung und einer dazu orthogonalen zweiten Querrichtung erstrecken, wobei die Brennstoffzellen jeweils in der Stapelrichtung gestapelt aufweisen: eine anodenseitige Bipolar-Halbplatte mit einer Brennstoff-Kanalstruktur zur Führung eines Brennstoffes; eine anodenseitige Gasdiffusionslage; eine Membran-Elektroden-Einheit, aufweisend eine Elektrolytmembran und in Stapelrichtung beiderseits davon angeordnete Elektrodenschichten, die eine Anode und eine Kathode für eine elektrochemische Reaktion des Brennstoffes mit einem Oxidationsmittel ausbilden; eine kathodenseitige Gasdiffusionslage; und eine kathodenseitige Bipolar-Halbplatte mit einer Oxidationsmittel-Kanalstruktur zur Führung des Oxidationsmittels,

According to a further aspect, the invention relates to a method for producing a fuel cell arrangement, which has:

• Forming a fuel cell arrangement by stacking fuel cells in a stacking direction, each of which is plate-shaped and, viewed orthogonally to the stacking direction, extends in a first transverse direction and a second transverse direction orthogonal thereto, the fuel cells each having, stacked in the stacking direction: an anode-side bipolar -Half-plate with a fuel channel structure for guiding a fuel; an anode-side gas diffusion layer; a membrane-electrode unit, comprising an electrolyte membrane and electrode layers arranged on both sides thereof in the stacking direction, which form an anode and a cathode for an electrochemical reaction of the fuel with an oxidizing agent; a cathode-side gas diffusion layer; and a cathode-side bipolar half-plate with an oxidizing agent channel structure for guiding the oxidizing agent,

According to the invention, it is provided in this manufacturing method that the bipolar half-plates are shaped on a lateral edge area in such a way that the bipolar half-plates come to rest against one another or at least come so close to one another when they are stacked at this lateral edge area A cavity extending continuously in the stacking direction is formed in a corresponding lateral edge region of the fuel cell arrangement, and that the method further comprises filling the cavity with a sealing material.

The “coming close to each other” of the bipolar half-plates creates a delimitation of the cavity at the relevant points, so that the sealing material does not escape at these points during filling. Depending on e.g. B. on the viscosity of the sealing material during filling, this can in practice, for. B. imply that the bipolar half-plates come closer to each other than 0.1 mm, in particular closer than 0.05 mm, at these points. As already mentioned, in the event that a section of the membrane-electrode unit (or some other layer such as sealing and / or electrical insulation layer) also acts as a delimitation of the cavity at a relevant point, this can “come close to one another "Also means apart from a mutual distance which corresponds to the thickness of the relevant layer (e.g. membrane-electrode unit) measured in the stacking direction, on which the bipolar half-plates (or e.g. ends of projections provided thereon) come to the plant.

The embodiments and special configurations described for the fuel cell arrangement according to the invention can also be provided, individually or in any combination, in an analogous manner as embodiments or special configurations of the production method according to the invention, and vice versa.

In one embodiment, the production method comprises, after filling with the sealing material, the implementation of temperature control of the fuel cell arrangement (for the thermally induced or accelerated curing of the sealing material). With a temperature control z. B. a temperature of more than 50 ° C., in particular more than 100 ° C., can be provided.

In one embodiment, the production method comprises, after the sealing material has hardened, mechanical bracing of the fuel cell arrangement or at least its lateral edge region.

• 1 eine Schnittansicht einer Brennstoffzelle gemäß eines Ausführungsbeispiels nach dem Stand der Technik,
• 2 eine Schnittansicht einer Brennstoffzellenanordnung aus gestapelt angeordneten Brennstoffzellen gemäß eines Ausführungsbeispiels, in einem ersten Stadium der Herstellung,
• 3 eine Schnittansicht der Brennstoffzellenanordnung von 2 in einem darauffolgenden zweiten Stadium der Herstellung,
• 4 eine Schnittansicht der Brennstoffzellenanordnung von 3 in einem darauffolgenden dritten Stadium der Herstellung, und
• 5 eine Schnittansicht einer Brennstoffzellenanordnung gemäß eines weiteren Ausführungsbeispiels, in einer der 4 entsprechenden Darstellung.

The invention is further described below on the basis of exemplary embodiments with reference to the accompanying drawings. They each show schematically:

• 1 a sectional view of a fuel cell according to an exemplary embodiment according to the prior art,
• 2 a sectional view of a fuel cell arrangement made of stacked fuel cells according to an exemplary embodiment, in a first stage of manufacture,
• 3 FIG. 3 is a sectional view of the fuel cell assembly of FIG 2 in a subsequent second stage of manufacture,
• 4th FIG. 3 is a sectional view of the fuel cell assembly of FIG 3 in a subsequent third stage of manufacture, and
• 5 a sectional view of a fuel cell arrangement according to a further embodiment, in one of the 4th corresponding representation.

1 shows a fuel cell 20th with a conventional structure, by means of which the chemical reaction energy of a supplied fuel (e.g. hydrogen) and a supplied oxidizing agent (e.g. air) can be converted into electrical energy.

The fuel cell 20th is plate-shaped and extends in a plate plane of this shape in a first transverse direction x and a second transverse direction y orthogonal thereto (e.g. with a rectangular contour).

The direction orthogonal to the plate plane spanned by the transverse directions x, y is referred to as the stacking direction z, since in practice it is mostly made up of a large number of such fuel cells stacked in the stacking direction z 20th a fuel cell assembly (“fuel cell stack”) is formed.

The fuel cell 20th is composed in each case of a plurality of plate-shaped shaped and stacked components arranged in the stacking direction z.

It is initially a bipolar half-plate on the anode side 22nd , on the inside (ie the inside of the fuel cell 20th facing side) a channel structure 24 is designed to guide the fuel, which is hereinafter also referred to as a fuel channel structure 24 referred to as.

Via the bipolar half-plate made of electrically conductive material (e.g. metal) 22nd is in operation of the fuel cell 20th generated electric current dissipated.

On the inside of the bipolar half-plate 22nd and thus on the fuel channel structure 24 adjacent is an electrically conductive gas diffusion layer permeable to the fuel 26th (z. B. carbon fleece) provided over which the fuel in operation of the fuel cell 20th to a membrane-electrode unit adjoining it in the stacking direction z 28 got.

The membrane-electrode unit 28 comprises an electrically non-conductive (in the case of hydrogen as fuel, proton-conductive) electrolyte membrane 30th and viewed in the stacking direction z on both sides thereof arranged electrically conductive and with a catalyst 35 (e.g. platinum or palladium) interspersed with electrode layers 32 and 34 (e.g. made of metal). The electrode layer 32 forms the anode and the electrode layer 34 the cathode for an electrochemical reaction of the fuel with the oxidizing agent.

In operation of the fuel cell 20th the fuel (e.g. hydrogen) is based on the fuel channel structure 24 via the gas diffusion layer on the anode side 26th to the electrode layer 32 (Anode) and the oxidizing agent (air) is applied to the electrode layer via a 34 (Cathode) adjoining cathode-side gas diffusion layer 36 to the electrode layer 34 introduced.

In the stacking direction z to this electrically conductive gas diffusion layer permeable to the oxidizing agent 36 adjacent is an electrically conductive cathode-side bipolar half-plate 38 provided, on the inside of which a channel structure 40 is designed to guide the oxidizing agent, hereinafter also as an oxidizing agent channel structure 40 designated.

The product of the electrochemical reaction, for example water, can be discharged via the oxidizing agent (e.g. air) -carrying fuel cell area, which is here e.g. B. the oxidizer channel structure 40 the bipolar half-plate 38 contains. The bipolar half-plate 38 is used when the fuel cell is in operation 20th on the cathode side as well to discharge the from the fuel cell 20th generated electric current.

In the fuel cell 20th must be the fuel-carrying area, ie fuel channel structure 24 , Gas diffusion layer 26th , Electrode layer 32 (Anode), and the oxidizing agent-carrying area, ie oxidizing agent channel structure 40 , Gas diffusion layer 36 , Electrode layer 34 (Cathode), must be sealed against each other in order to prevent a gas exchange between these areas that is detrimental to the power efficiency.

To this end, the fuel cell 20th a seal on its side edge area 50 on that on the bipolar half-plate 22nd , the bipolar half-plate 38 and the membrane-electrode assembly 28 abuts to from the bipolar half-plate 22nd to the membrane electrode unit 28 to and from the membrane-electrode assembly 28 to the bipolar half-plate 38 to seal off. The seal 50 closes sideways (cross direction y in 1 ) flush with the side edges 23 , 39 of the bipolar half plates 22nd , 38 away.

The present invention aims at a fuel cell such. B. the in 1 shown, or to show a new way in a fuel cell arrangement formed from such fuel cells, with which seals for the desired guidance of fuel and / or oxidizing agent and / or optionally provided cooling medium in a space between two adjacent fuel cells can be realized.

With reference to the 2 until 4th a first embodiment and with reference to FIG 5 a second exemplary embodiment of a fuel cell arrangement (“fuel cell stack”) with such a novel seal is described (to replace the one in 1 seal shown 50 ).

In the following description of further exemplary embodiments, the same reference symbols are used for components that have the same effect. Essentially, only the differences to the exemplary embodiment (s) already described are discussed and the description of previous exemplary embodiments (in particular of the in 1 shown example).

2 Fig. 10 illustrates an embodiment of a fuel cell assembly 10 After completing a first step of their production, in which a plurality of fuel cells are stacked in a stacking direction z 20th was ordered.

Each of the fuel cells, which are identically designed in the example 20th is like the one in 1 The conventional fuel cell shown is plate-shaped and, viewed orthogonally to the stacking direction z, extends in a first transverse direction x and a second transverse direction y orthogonal thereto, and has, stacked in the stacking direction z (in the order specified): an anode-side bipolar half-plate 22nd with a fuel channel structure 24 for guiding a fuel; an anode-side gas diffusion layer 26th ; a membrane-electrode unit 28 with an electrolyte membrane 30th and electrode layers arranged on both sides thereof in the stacking direction z 32 and 34 who have favourited an anode 32 and a cathode 34 represent for the electrochemical reaction; a cathode-side gas diffusion layer 36 ; and a cathode-side bipolar half-plate 38 with an oxidizer channel structure 40 to guide the oxidizing agent.

In order to operate the individual fuel cells 20th the fuel cell assembly 10 the fuel channel structures 24 The fuel cell arrangement has to supply or flow through the fuel 10 at least one fuel inlet and at least one fuel outlet (not shown in the figures), each of which via openings (through openings) in the individual fuel cells which are arranged congruently in the xy plane 20th with the individual fuel channel structures 24 are connected. In this way, for the fuel cell assembly 10 at least one in the stacking direction z through the fuel cell arrangement 10 running fuel supply channel and at least one in the stacking direction z through the fuel cell arrangement 10 running fuel discharge channel can be formed by inlet passage openings and outlet passage openings which are each arranged congruently in the xy plane.

In an analogous manner to the oxidizer channel structures 40 to be supplied with the oxidizing agent, the fuel cell arrangement 10 at least one oxidizing agent inlet and at least one oxidizing agent outlet, each of which via openings in the fuel cells which are arranged congruently in the xy plane 20th with the individual oxidizing agent channel structures 40 are connected. Thus, at least one can in the stacking direction z through the fuel cell arrangement 10 running oxidizing agent supply channel and at least one in the stacking direction z through the fuel cell arrangement 10 running oxidizing agent discharge channel are formed by inlet and outlet passage openings which are arranged congruently in each case in the xy plane (not shown in the figures).

In contrast to the in 1 illustrated conventional fuel cell or a The fuel cell stack thus formed is, in the exemplary embodiment, the fuel cell arrangement 10 according to 2 a different type of sealing of the fuel-conducting area and the oxidizing agent-conducting area is provided.

It is essential that the bipolar half-plates 22nd , 38 on a side edge area (in 2 shown on the left) are designed in such a way that the bipolar half-plates 22nd , 38 due to the stacking arrangement on this lateral edge area come into contact with one another in places or at least come close to one another in such a way that on a corresponding lateral edge area of the fuel cell arrangement 10 a cavity extending continuously in the stacking direction z 49 is trained.

In areas of the individual fuel cells 20th extends the cavity 49 each closed in a ring-shaped manner without interruptions in the circumferential direction around the respective fuel cell 20th (In the sectional view of 2 is the cavity 49 relatively wide in these areas). The cavity is in these areas 49 delimited laterally outside or laterally inward by an "outer wall" running in a closed ring shape and an "inner wall" running in a closed ring shape, these walls being formed by a special shape of the bipolar half-plates (protrusions protruding in the stacking direction z), as follows will be explained in more detail.

In the areas of the transitions between adjacent fuel cells 20th , ie in the area of the two bipolar half-plates adjacent to one another there, the cavity extends 49 however, in each case not continuously but closed in a ring with interruptions in the circumferential direction all around, as the cavity in these areas 49 is formed by one or more (e.g. arranged evenly distributed over the circumference) in the stacking direction z (in 2 the vertical direction) through the two bipolar half-plates through openings. The section plane of the section view of 2 runs in the area of such an opening. In the example shown, these openings form, so to speak, “riser sections” of the cavity 49 during their filling with the sealing material 50 .

the 3 and 4th illustrate the further course of the manufacturing process for the fuel cell arrangement 10 and show in one of the 2 corresponding illustration of further stages of this manufacturing process in which the cavity 49 gradually with an initially still liquid sealing material 50 is filled.

In the example shown according to the 2 until 4th the filling takes place with the sealing material 50 from the bottom up, ie the sealing material 50 is at a lower end (not shown in the figures) of the fuel cell stack (“lower end plate”) via one or more openings in the cavity located there 49 fed. In particular, such a lower end plate (and / or upper end plate) can, for. B. be provided with only one opening extending in the stacking direction z, or z. B. with fewer openings extending in the stacking direction z than the bipolar half-plates 22nd , 38 inside the stack. Inside the stack, the bipolar half-plates have 22nd , 38 preferably a plurality of such openings.

3 shows a second stage in which the sealing material 50 in the cavity 49 the area of the fuel cell identified in the figures 20th has achieved, and 4th shows a subsequent third stage in which the sealing material 50 those in the field of this fuel cell 20th lying section of the cavity 49 already completely filled out.

The sealing material 50 is through the mentioned openings of the bipolar half-plates 22nd , 38 little by little in the area of the individual fuel cells 20th located and these fuel cells 20th in each case surrounding sections of the cavity 49 filled.

After the cavity has been completely filled 49 with the sealing material 50 , ie in the example up to one or more openings (not shown) which are located at an upper end of the fuel cell stack (“upper end plate”), curing takes place. The curing can, for. B. be realized by a subsequent waiting time at a preferably elevated temperature, in which (z. B. thermally and / or chemically caused) a curing or crosslinking of the sealing material 50 he follows.

The filling of the sealing material 50 into the cavity 49 can e.g. B. be done by a gravimetrically driven "running in". Alternatively or additionally, the sealing material can also be subjected to pressure 50 be provided, so that in this case filling can also take place “from bottom to top” (by “pressing in” the sealing material 50 ). As an alternative or in addition to pressurization of the supplied sealing material 50 For example, a negative pressure can be provided at the opening or openings provided at the opposite end of the arrangement. With a negative pressure, the sealing material 50 advantageous in the cavity 49 Be "drawn in".

The sealing material that maintains an elastic state after curing 50 forms on the fuel cells 20th the fuel cell assembly 10 a “seal 50” and in this case, in the example, seals the fuel-carrying and oxidizing agent-carrying areas from one another, and also seals these areas from the environment, ie z. B. the atmosphere or an interior of a (not shown in the figures) housing of the fuel cell assembly 10 .

The sealing material 50 or the seal created by its hardening is formed from an electrically insulating, elastic plastic material.

In the embodiment according to 2 until 4th became the bipolar half plates 22nd , 38 for the interior of the fuel cell assembly 10 each prefabricated separately from one another and before they are inserted into the fuel cell arrangement 10 connected to each other in pairs (e.g. by gluing or welding), so that during the production of the fuel cell stack 10 Bipolar plates were used, each composed of two bipolar half-plates. At the two ends viewed in the stacking direction, individual bipolar half-plates were used as lower and upper "end plates" 38 or. 22nd arranged. When manufacturing the bipolar half-plates 22nd , 38 or the bipolar plates formed therefrom, their already mentioned openings (for the later passage of the sealing material 50 ) educated.

In the exemplary embodiment shown, fuel cells that are adjacent to one another in the stacking direction z are located at each transition 20th the bipolar half-plates located there 22nd , 38 both in their central area and in their lateral edge areas directly (without a gap) to one another.

In this area of the transitions between adjacent fuel cells viewed in the stacking direction z 20th an outer wall (left wall in the figures) of the cavity is seen in the lateral direction 49 due to the adjacent side edges of the respective bipolar half-plates 22nd , 38 formed, and an inner wall viewed in the lateral direction (in the figures somewhat to the right of the outer wall) of the cavity 49 through adjacent "intermediate areas" 23 ' , 39 ' of the bipolar half plates 22nd , 38 educated. The relevant bipolar half-plates are in this area 22nd , 38 As already mentioned, provided with openings extending in the stacking direction z, which z. B. can be designed as coaxial bores, perforations, perforations or other openings, which the areas of the cavity 49 Let them communicate with each other below and above the transition area, ie connect them with each other "fluidly". The openings can advantageously, for. B. substantially uniformly and in particular z. B. equidistant over the circumference of the bipolar half-plates 22nd , 38 be provided distributed. In the 2 until 4th is such an opening (as a section of the cavity 49 ) can be seen, since the sectional plane in these figures runs through such an opening. In an advantageous embodiment, z. B. at least 10 or z. B. at least 20 such openings are provided.

In the example shown is for the fuel cells 20th on a lateral edge area of the respective membrane-electrode unit 28 a so-called "sub-seal" 42 provided, which has a sealing surface on the membrane-electrode unit 28 provides and in the manufacture of the membrane-electrode unit 28 was formed (e.g. molded). Deviating from the example shown, the subgasket could 42 (which also serves as a holding frame for the membrane-electrode unit in conventional fuel cell arrangements) can also be omitted.

On the side edge of the fuel cells 20th protrudes the electrolyte membrane 30th the membrane electrode assembly 28 in the lateral direction over the lateral edges of the gas diffusion layers 26th and 36 out, in the example together with the subgasket 42 up to the side edges 23 , 39 of the bipolar half plates 22nd , 38 . Notwithstanding this example, the electrolyte membrane could 30th however, not or at least not so far protrude and in this case z. B. already at the "intermediate areas" 23 ' , 39 ' of the bipolar half plates 22nd , 38 end up.

As for the area of the individual fuel cells 20th As far as itself is concerned, there is an outer wall of the cavity 49 due to the side edges protruding close together 23 , 39 of the respective bipolar half-plates 22nd , 38 formed, the bipolar half-plates 22nd , 38 in this area are designed so that the side edge 23 (the anode-side bipolar half-plate 22nd ) and the side edge 39 (the cathode-side bipolar half-plate 38 ) one in each case in the stacking direction z to the other bipolar half-plate 38 or. 22nd have protruding projection.

These protrusions are used inside each fuel cell 20th otherwise between the two bipolar half-plates 22nd , 38 When viewed in the stacking direction z, the existing distance is bridged and the wall of the cavity that delimits the outside 49 educated.

In the example shown, there is a gap between the ends of the projections of the side edges 23 , 39 the side edge of the membrane-electrode assembly 28 , the one from the side edge of the one with the lower seal in the example 42 coated electrolyte membrane 30th is formed, but different from this example z. B. only from an outer edge of the sub-seal 42 could be formed (as the electrolyte membrane 30th not to the side edges 23 , 39 enough, but viewed in the lateral direction before this ends, z. B. in the area of the cavity 49 , or z. B. at the level of the intermediate areas 23 ' , 39 ' , or z. B. further inside). It is advantageous in this context that the projections on the side edges 23 , 39 viewed in the stacking direction z are dimensioned to be the same height.

In the area of the cavity 49 is the membrane-electrode assembly 28 z. B. with a perforation or z. B. provided with (z. B. arranged distributed over the circumference) openings, which during the filling of the cavity 49 a passage of the sealing material 50 allow. The cutting plane of the 2 until 4th runs in the area of such a breakthrough.

In a departure from the example shown, the side edge of the membrane-electrode unit could 28 also in the area of the cavity 49 ending and the mentioned gap (between the edges 23 and 39 ) be dimensioned so that when filling the cavity 49 the (electrically insulating) sealing material 50 penetrates a little into this gap and thus effects mechanical stabilization at this point and electrical insulation between the bipolar half-plates 22nd , 38 inside the fuel cell 20th ensures.

The projections on the side edges could also deviate from the example shown 23 , 39 of the respective bipolar half-plates 22nd , 38 also bear directly against each other, but then at least in the contact area (contact surface between the projections) an otherwise realized electrical insulation is to be provided, z. B. by an electrically insulating coating on at least one of the two adjacent projections.

In the example shown, in the area of each fuel cell 20th an inner wall of the cavity viewed in the lateral direction 49 through the already mentioned "intermediate areas" 23 ' , 39 ' of the bipolar half plates 22nd , 38 formed, each on one of the two sides (anode side or cathode side) of the membrane-electrode unit 28 issue.

Similar to the side margins 23 , 39 also indicate the intermediate areas 23 ' , 39 ' of the bipolar half plates 22nd , 38 each have a protrusion protruding in the stacking direction z (and toward the respective other bipolar half-plate), the ends of these protrusions each on one of the two sides of the membrane-electrode unit 28 (here: their sub-seal 42 ) issue. In this context, it is advantageous in the example that these projections, viewed in the stacking direction z, are of the same size.

With "intermediate area" ( 23 ' , 39 ' ) of the bipolar half-plates 22nd , 38 is meant an area that is viewed in the lateral direction from both the lateral edge 23 or. 39 the relevant bipolar half-plate 22nd or. 38 as well as from a central area of the relevant bipolar half-plate 22nd or. 38 is spaced.

With the protrusions of the intermediate areas 23 ' , 39 ' of the bipolar half plates 22nd , 38 are inside every fuel cell 20th Considered in the stacking direction z, otherwise existing gaps between the bipolar half-plates on the one hand 22nd , 38 and on the other hand the two sides of the membrane-electrode assembly 28 bridged, and in the example shown, the projections form together with an intermediate section of the membrane-electrode unit 28 the inner wall of the cavity 49 . The projections protrude against one another except for a mutual spacing which is the same as the thickness of the membrane-electrode unit 28 corresponds at this point. However, this distance could also be significantly smaller than the thickness of the membrane-electrode unit 28 be sized so that the membrane-electrode assembly 28 (or in this example especially its sub-seal 42 ) is somewhat compressed (flexibly pressed / deformed) at this point. The distance can e.g. B. less than 0.9 times, in particular less than 0.8 times an uncompressed thickness of the membrane-electrode unit 28 be measured.

As already mentioned, the lateral edge of the membrane-electrode unit could deviate from the example shown 28 z. B. already in the area of the cavity 49 end, or z. B. already in the area of the projections of the intermediate areas 23 ' , 39 ' of the bipolar half plates 22nd , 38 end up.

In the latter cases in particular, the sealing material 50 , which in the areas of the individual fuel cells 20th these each surrounds, advantageously the membrane-electrode unit 28 seal laterally outwards (and thus against the environment or a housing). In addition, the sealing material 50 advantageous compared to gas transfer from one side of the membrane-electrode unit to the other 28 seal.

5 Fig. 10 illustrates another embodiment of a fuel cell assembly 10 , in one of the 4th corresponding sectional view, ie after filling a cavity 49 with a sealing material 50 .

In contrast to that in the 2 until 4th The fuel cell assembly shown are in the fuel cell assembly 10 according to 5 at the transitions between adjacent fuel cells 20th the bipolar half-plates located there 22nd , 38 (or at least their central regions), viewed in the stacking direction z, are significantly spaced apart from one another.

In the embodiment according to 5 This spacing is used in the area of the transitions between the fuel cells 20th during operation of the fuel cell arrangement 10 to carry a cooling medium (e.g. water). Here z. B. be provided that a further channel structure for guiding the cooling medium is formed in the space.

Since in the example shown the 5 the bipolar half-plates 22nd , 38 are also spaced apart from one another at their lateral edge regions, at least one of the two bipolar half-plates has at its edge 23 or. 39 a projection protruding towards the other bipolar half-plate, and also has at least one of the two bipolar half-plates at its intermediate area 23 ' , 39 ' a protrusion protruding towards the other bipolar half-plate in order to bridge the gap in this transition area and to form the outer wall of the cavity and the inner wall of the cavity (alternatively, instead of the protrusions, e.g. seals to delimit the cavity 49 inserted between the bipolar half-plates).

Sealing material is advantageously located 50 also in an area between the bipolar half-plates and thus also ensures a seal for the cooling medium (e.g. water) located between them in the middle area of the bipolar half-plates. The sealing material 50 at this point prevents the cooling medium from escaping sideways to the outside.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• EP 2357698 B1 [0004]
• EP 2445045 B1 [0004]
• EP 2584635 B1 [0004]
• EP 2946431 B1 [0004]
• EP 3316377 A1 [0004]

Claims (9)

Fuel cell arrangement (10), having fuel cells (20) arranged stacked in a stacking direction (z), each of which is plate-shaped and viewed orthogonally to the stacking direction (z), each in a first transverse direction (x) and a second transverse direction orthogonal thereto (y) The fuel cells (20) each have, stacked in the stacking direction (z): - an anode-side bipolar half-plate (22) with a fuel channel structure (24) for guiding a fuel, - an anode-side gas diffusion layer (26), - a Membrane-electrode unit (28), comprising an electrolyte membrane (30) and electrode layers (32, 34) arranged on both sides thereof in the stacking direction (z), which have an anode (32) and a cathode (34) for an electrochemical reaction of the fuel an oxidizing agent, - a cathode-side gas diffusion layer (36), - a cathode-side bipolar half-plate (38) with an oxidizing agent channel structure (40) for guiding the oxidizing agent, characterized in that the bipolar half-plates (22, 38) are designed on a lateral edge area in such a way that the bipolar half-plates (22, 38) in this lateral edge area are in contact with one another or at least close to one another protrude towards one another that a cavity (49) extending continuously in the stacking direction (z) is formed on a corresponding lateral edge region of the fuel cell arrangement (10), and that this cavity (49) is filled with a sealing material (50). Fuel cell assembly (10) according to Claim 1 , wherein the cavity (49) extends all around, viewed in a circumferential direction of the fuel cell arrangement (10). Fuel cell arrangement (10) according to one of the preceding claims, wherein an outer wall of the cavity (49) viewed in the lateral direction is formed by side edges of the bipolar half-plates (22, 38) lying against one another or at least protruding close to one another. Fuel cell assembly (10) according to Claim 3 wherein in each fuel cell (20) the side edge of the anode-side bipolar half-plate (22) and / or the side edge of the cathode-side bipolar half-plate (38) has a protrusion protruding in the stacking direction (z). Fuel cell arrangement (10) according to one of the preceding claims, wherein an inner wall of the cavity (49) viewed in the lateral direction - is formed in the area of each fuel cell (20) by intermediate areas (23 ', 39') of the bipolar half-plates (22, 38) which each rest on one of the two sides of a lateral edge of the membrane-electrode unit (28), and - is formed in the area of a transition between adjacent fuel cells (20) by intermediate areas (23 ', 39') of the bipolar half-plates (22, 38) which rest against one another. Fuel cell assembly (10) according to Claim 5 In each fuel cell (20) the intermediate area (23 ') of the anode-side bipolar half-plate (22) and / or the intermediate area (39') of the cathode-side bipolar half-plate (38) has a protrusion protruding in the stacking direction (z). Fuel cell arrangement (10) according to one of the preceding claims, wherein at each transition between fuel cells (20) adjacent to one another in the stacking direction (z) the bipolar half-plates (22, 38) located there lie directly against one another in their central area. Fuel cell arrangement (10) according to one of the Claims 1 until 6th At each transition between fuel cells (20) adjacent to one another in the stacking direction (z), the bipolar half-plates (22, 38) located there are spaced apart from one another in their central region. Method for producing a fuel cell arrangement (10) according to one of the preceding claims, comprising - forming a fuel cell arrangement (10) by stacking fuel cells (20) in a stacking direction (z), each of which is plate-shaped and orthogonal to the stacking direction (z) viewed in a first transverse direction (x) and a second transverse direction (y) orthogonal thereto, the fuel cells (20) each having, stacked in the stacking direction (z): an anode-side bipolar half-plate (22) with a fuel channel structure ( 24) for guiding a fuel; an anode-side gas diffusion layer (26); a membrane electrode unit (28), comprising an electrolyte membrane (30) and electrode layers (32, 34) arranged on both sides thereof in the stacking direction (z), the anode (32) and a cathode (34) for an electrochemical reaction of the fuel form with an oxidizing agent; a cathode-side gas diffusion layer (36); and a cathode-side bipolar half-plate (38) with an oxidizing agent channel structure (40) for guiding the oxidizing agent, characterized in that the bipolar half-plates (22, 38) are shaped at a lateral edge area in such a way that the bipolar half-plates (22 , 38) in the stacking arrangement on this lateral edge area come into contact with one another in places or at least come close to one another in such a way that on a corresponding lateral edge area of the fuel cell arrangement (10) a cavity (49) extending continuously in the stacking direction (z) is formed, and that the method further comprises: - filling the cavity (49) with a sealing material (50).

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