DE102021105029A1 - Electrochemical unit for an electrochemical device and method of making an electrochemical unit for an electrochemical device - Google Patents

Abstract

An electrochemical unit for an electrochemical device, comprising a membrane, a first electrode, a second electrode, a first gas diffusion layer, a second gas diffusion layer, a bipolar plate and a seal, which comprises at least one sealing element which is attached to the membrane, to the first electrode , is connected to the second electrode, to a subgasket and/or to the bipolar plate of the electrochemical unit and/or to a bipolar plate of a further electrochemical unit adjacent to the electrochemical unit, which with a smaller number of process steps and preferably also with simpler ones and thus more cost-effective individual processes can be produced, it is proposed that the second electrode and the second gas diffusion layer form an electrochemically active composite, in which the second electrode is formed as a coating applied to the second gas diffusion layer.

Description

The present invention relates to an electrochemical unit for an electrochemical device comprising a membrane, a first electrode, a second electrode, a first gas diffusion layer, a second gas diffusion layer, a bipolar plate and a seal, which comprises at least one sealing element which is attached to the membrane the first electrode is connected to the second electrode, to a subgasket and/or to the bipolar plate of the electrochemical unit and/or to a bipolar plate of a further electrochemical unit adjacent to the electrochemical unit.

In electrochemical units of this type known from the prior art, the first electrode and the second electrode are formed on the membrane, and the unit formed from these three elements (CCM for "Catalyst Coated Membrane") is placed between the first gas diffusion layer and the second gas diffusion layer inserted. The seal of the electrochemical unit can be injection molded onto the first gas diffusion layer and/or onto the second gas diffusion layer.

The entirety of the membrane, the first electrode, the second electrode, the first gas diffusion layer and the second gas diffusion layer is collectively referred to as a membrane-electrode assembly (MEA).

In the prior art, this MEA must be assembled from three components, namely the membrane (CCM) provided with the two electrodes and the two gas diffusion layers, which means that a number of component tolerances and assembly tolerances add up. The handling of these three flexible and sensitive components is very demanding. The sealing elements arranged on the gas diffusion layers show distortions.

The processes for manufacturing the membrane with the electrodes arranged thereon on the one hand and the gas diffusion layers with the sealing elements arranged thereon on the other hand have to be carried out very precisely and are therefore time-consuming and expensive. Furthermore, additional space is required to compensate for the tolerances that occur during manufacture and assembly.

The present invention is based on the object of creating an electrochemical unit of the type mentioned at the outset, which can be produced with a smaller number of process steps and preferably also with simpler and therefore more cost-effective individual processes.

This object is achieved according to the invention with an electrochemical unit having the features of the preamble of claim 1 in that the second electrode and the second gas diffusion layer form an electrochemically active composite in which the second electrode is formed as a coating applied to the second gas diffusion layer.

The solution according to the invention is based on the concept of forming an electrochemically active composite which comprises at least the second electrode and the second gas diffusion layer. Since at least the second electrode is already materially connected to the second gas diffusion layer, the otherwise necessary step of assembling the second gas diffusion layer with the second electrode is omitted.

In addition to the second gas diffusion layer and the second electrode, the electrochemically active composite can also include the membrane of the electrochemical unit or at least a part of the membrane of the electrochemical unit, the membrane or the part of the membrane being designed as a coating applied to the second electrode.

Provision can furthermore be made for the electrochemically active composite to also include the first electrode of the electrochemical unit in addition to the second gas diffusion layer, the second electrode and the membrane, the first electrode being configured as a coating applied to the membrane.

The formation of the electrochemically active composite reduces the number of components to be assembled with one another. As a result, the problems that occur due to component distortion are reduced, the tolerance chains become shorter and/or installation space can be saved. The number of process steps required for producing the electrochemical unit is reduced, and the individual processes required for producing and assembling the components of the electrochemical unit are simplified and therefore more cost-effective.

A membrane-electrode assembly in which at least part of the membrane and the second electrode are formed in situ on the second gas diffusion layer is referred to as a "direct MEA".

Such a direct MEA can be produced in a continuous roll-to-roll process.

Only at the end of the Direct MEA manufacturing process are the membrane electrode assemblies manufactured in the roll process separated.

Individual layers of the Direct MEA can be masked if necessary during the roll-to-roll process.

In principle, it can be provided that the first electrode and the first gas diffusion layer form a further electrochemically active composite, in which the first electrode is formed as a coating applied to the first gas diffusion layer.

In addition to the first gas diffusion layer and the first electrode, the further electrochemically active composite can also include the membrane of the electrochemical unit or at least a part of the membrane of the electrochemical unit, the membrane or the part of the membrane being designed as a coating applied to the first electrode .

In this case, the membrane-electrode assembly as a whole is produced by assembling the two electrochemically active composites with one another.

The disadvantage here, however, is that the first gas diffusion layer, to which the sealing element of the seal is attached, also serves as a substrate for the production of the first electrode and at least part of the membrane of the electrochemical device.

If the sealing member is formed by injection molding on the first gas diffusion layer after the first electrode and a part of the membrane have been formed on the first gas diffusion layer, the consequence is that high waste costs are incurred if the molding process fails and the unit from the first Gas diffusion layer, the first electrode and optionally at least part of the membrane and the sealing element must be discarded.

It is therefore advantageous if the first electrode and the entire membrane form part of the electrochemically active composite, which is produced by coating the second gas diffusion layer.

In a preferred embodiment of the invention, it is therefore provided that the electrochemically active composite of the electrochemical unit comprises the membrane as a whole and the first electrode, with the first electrode being designed as a coating applied to the membrane.

In this case, the membrane is preferably designed as a whole as a coating applied to the second electrode.

Furthermore, it is favorable if in this case no sealing element of the seal of the electrochemical unit is connected to the second gas diffusion layer.

In a particular embodiment of the invention, it can be provided that an outer edge of the first gas diffusion layer is offset inwards, at least in sections, relative to an outer edge of the second gas diffusion layer, or the outer edge of the second gas diffusion layer is offset inwards, at least in sections, relative to an outer edge of the first gas diffusion layer .

The directions “inward” and “outward” refer to the center of the membrane-electrode assembly or the electrochemical unit. “Offset inwards” thus means offset in the direction of the center of the membrane-electrode assembly or the electrochemical unit. “Offset” means offset in the direction away from the center of the membrane electrode assembly or the electrochemical unit. In all of the drawings accompanying this specification, the center of the membrane-electrode assembly and electrochemical unit is to the left of the outer edge portion of the membrane-electrode assembly and electrochemical unit shown in the cross-section drawings.

The seal of the electrochemical unit comprises, for example, a first sealing element that is attached to the first gas diffusion layer and/or a second sealing element that is attached to the second gas diffusion layer.

The first sealing element is preferably integrally bonded to the first gas diffusion layer, for example by injection molding.

The second sealing element is preferably integrally bonded to the second gas diffusion layer, for example by injection molding.

The respective sealing element can comprise at least one connection area, which extends into the first gas diffusion layer or into the second gas diffusion layer.

Such a connection area of the sealing element thus forms at the same time an infiltration area of the relevant gas diffusion layer, in which the relevant gas diffusion layer is infiltrated with the sealing material of the respective sealing element.

In a particular embodiment of the invention, it is provided that at least one sealing element of the seal comprises a bipolar plate sealing area, with which the sealing element seals in the assembled state of the electrochemical unit on the bipolar plate of the electrochemical unit or on a bipolar plate of a further electrochemical unit adjacent to the electrochemical unit applied.

If in this description and in the appended claims it is mentioned that one element rests sealingly on another, this is to be understood in such a way that the elements in question are not connected to one another by a material bond, but by a sealing force, which is preferably exerted by means of a clamping device the electrochemical device is generated, are pressed against each other in the assembled state of the electrochemical unit.

In principle, the bipolar plate sealing area can be designed as a flat seal or a strip seal.

Such a strip seal has a sealing surface formed from intersecting sealing strips which delimit recesses in the form of prisms with a polygonal cross section. This polygonal cross section can have the shape of a square, a rhombus or a hexagon, for example.

In the case of a surface seal or strip seal, the bipolar plate sealing area is preferably in contact with a substantially flat sealing surface against a preferably also substantially flat sealing surface of the bipolar plate of the electrochemical unit or of the bipolar plate of the further electrochemical unit adjacent to the electrochemical unit.

Alternatively or in addition to this, it can also be provided that the bipolar plate sealing area has one, two or more sealing lips, with which the bipolar plate sealing area in the mounted state of the electrochemical unit on the bipolar plate of the electrochemical unit or on the bipolar plate of the electrochemical unit adjacent further electrochemical unit sealingly applied.

In a particular configuration of the electrochemical unit, it is provided that the seal comprises two sealing elements which are pressed together when the electrochemical unit is in the assembled state.

Furthermore, it can be provided that at least one sealing element of the seal of the electrochemical unit comprises an electrode sealing area, with which the sealing element bears sealingly on the first electrode or on the second electrode of the electrochemical unit when the electrochemical unit is in the assembled state,
and/or that at least one sealing element of the seal of the electrochemical unit comprises a membrane sealing area, with which the sealing element bears sealingly against the membrane of the electrochemical unit when the electrochemical unit is in the assembled state.

In principle, such an electrode sealing area can be designed as a flat seal or a strip seal.

In this case, the electrode sealing area is preferably in sealing contact with a substantially flat sealing surface against a preferably likewise substantially flat sealing surface of the first electrode or the second electrode.

Alternatively or additionally, it can also be provided that the electrode sealing area of the sealing element has one, two or more sealing lips, with which the electrode sealing area bears sealingly on the first electrode or on the second electrode when the electrochemical unit is in the assembled state.

In principle, a membrane sealing area can also be designed as a flat seal or a strip seal.

In this case, the membrane sealing area is preferably in sealing contact with a substantially flat sealing surface against a preferably likewise substantially flat sealing surface of the membrane of the electrochemical unit.

Alternatively or additionally, it can be provided that the membrane sealing area has one, two or more sealing lips, with which the membrane sealing area bears sealingly against the membrane of the electrochemical unit in the assembled state of the electrochemical unit.

In a particular embodiment of the electrochemical unit, it is provided that the seal comprises at least two separate sealing elements, of which an inner sealing element ment is offset inward relative to an outer sealing element.

In order to create a seal with a particularly high level of fluid tightness, it can be provided that the seal comprises at least two sealing elements, one sealing element having a groove into which the other sealing element engages.

Furthermore, it can be provided that an outer edge of the first electrode of the electrochemical unit is offset inwards, i.e. towards the center of the electrochemical unit, at least in sections compared to an outer edge of the second electrode of the electrochemical unit, or an outer edge of the second electrode of the electrochemical unit is offset inwards, ie towards the center of the electrochemical unit, at least in sections relative to an outer edge of the first electrode of the electrochemical unit.

The seal of the electrochemical unit can comprise at least one sealing element which is connected to a gas diffusion layer of the electrochemical unit, to the bipolar plate of the electrochemical unit and/or to a bipolar plate of a further electrochemical unit adjacent to the electrochemical unit.

Furthermore, in special configurations of the electrochemical unit it can be provided that the seal comprises at least one sealing element which is attached to a gas diffusion layer of the electrochemical unit, to an electrode of the electrochemical unit and/or to the bipolar plate of the electrochemical unit and/or to a bipolar plate of one of the electrochemical unit adjacent further electrochemical unit is connected.

The sealing element in question is preferably integrally bonded, for example by injection molding, to the gas diffusion layer in question of the electrochemical unit, to the electrode in question of the electrochemical unit and/or to the bipolar plate of the electrochemical unit and/or to the bipolar plate of the further electrochemical unit adjacent to the electrochemical unit connected.

In special configurations of the electrochemical unit, it can be provided that the first electrode and the first gas diffusion layer form an electrochemically active composite, in which the first electrode is designed as a coating applied to the first gas diffusion layer.

In particular configurations of the electrochemical unit it is provided that the electrochemical unit comprises an edge reinforcement arrangement or a “subgasket” which is connected to the first electrode, to the membrane and/or to the second electrode of the electrochemical unit.

Such a subgasket can in particular comprise a film.

The subgasket can be attached to the first electrode, to the membrane and/or to the second electrode of the electrochemical unit, for example by gluing and/or by hot pressing.

In a particular embodiment of the electrochemical unit, at least one sealing element of the seal comprises at least one subgasket sealing area, with which the sealing element bears sealingly against a subgasket of the electrochemical unit when the electrochemical unit is in the assembled state.

Such a subgasket sealing area can basically be designed as a flat seal or a strip seal.

In this case, the subgasket sealing area in question preferably bears with an essentially flat sealing surface against a preferably also essentially flat sealing surface of the subgasket.

Alternatively or additionally, it can also be provided that the subgasket sealing area in question has one, two or more sealing lips, by means of which the subgasket sealing area bears sealingly against the subgasket when the electrochemical unit is in the assembled state.

The sealing element can comprise a first subgasket sealing area which, when the electrochemical unit is in the assembled state, rests sealingly against a first area of the subgasket which is fixed to the first electrode, to the second electrode or to the membrane of the electrochemical unit.

Furthermore, the sealing element can comprise a second subgasket sealing area which, when the electrochemical unit is in the assembled state, bears sealingly against a second area of the subgasket which, in the assembled state of the electrochemical unit, bears in a sealing manner on the bipolar plate of the electrochemical unit or on a bipolar plate of one of the electrochemical unit neighboring further electrochemical Unit of the electrochemical device is sealingly applied.

The present invention further relates to a method of manufacturing an electrochemical unit for an electrochemical device.

The present invention is based on the further object of creating such a method for producing an electrochemical unit for an electrochemical device, which requires a small number of process steps and in which the individual processes can preferably be carried out simply and inexpensively.

• - Anbinden mindestens eines Dichtungselements einer Dichtung der elektrochemischen Einheit an eine Membran, an eine erste Elektrode, an eine zweite Elektrode, an ein Subgasket und/oder an eine Bipolarplatte der elektrochemischen Einheit und/oder an eine Bipolarplatte einer der elektrochemischen Einheit benachbarten weiteren elektrochemischen Einheit;
• - Erzeugen mindestens eines elektrochemisch aktiven Verbundes durch Applizieren mindestens einer Elektrode als Beschichtung auf mindestens eine Gasdiffusionslage der elektrochemischen Einheit;
• - Assemblieren des mindestens einen elektrochemisch aktiven Verbundes und des mindestens einen Dichtungselements.

This object is achieved according to the invention by a method for producing an electrochemical unit for an electrochemical device, which comprises the following:

• - Connecting at least one sealing element of a seal of the electrochemical unit to a membrane, to a first electrode, to a second electrode, to a subgasket and/or to a bipolar plate of the electrochemical unit and/or to a bipolar plate of a further electrochemical unit adjacent to the electrochemical unit ;
• - Generating at least one electrochemically active composite by applying at least one electrode as a coating to at least one gas diffusion layer of the electrochemical unit;
• - Assembling the at least one electrochemically active composite and the at least one sealing element.

The method according to the invention is particularly suitable for producing the electrochemical unit according to the invention for an electrochemical device.

• - Applizieren der gesamten Membran als Beschichtung auf die zweite Elektrode; und
• - Applizieren der ersten Elektrode als Beschichtung auf die Membran.

A preferred embodiment of the method according to the invention for producing an electrochemical unit for an electrochemical device comprises the following:

• - Applying the entire membrane as a coating to the second electrode; and
• - Application of the first electrode as a coating on the membrane.

The electrochemically active composite produced in this way comprises the second gas diffusion layer, the second electrode applied to the second gas diffusion layer, the membrane applied to the second electrode and the first electrode applied to the membrane.

Further preferred configurations of the method according to the invention for producing an electrochemical unit for an electrochemical device have already been explained above in connection with the special configurations of the electrochemical unit according to the invention for an electrochemical device.

The electrochemical unit according to the invention is suitable in particular as a component of an electrochemical device which comprises a plurality of such electrochemical units which follow one another in a stacking direction of the electrochemical device.

The electrochemical unit according to the invention is suitable in particular for use in an electrochemical device which is designed as a fuel cell stack, in particular a polymer electrolyte membrane fuel cell stack, or as an electrolyzer.

Such a fuel cell stack is particularly suitable for use in motor vehicles.

The at least one sealing element of the electrochemical unit preferably comprises an elastomeric material, for example a silicone-containing and/or silicone-based elastomeric material, or is formed from such an elastomeric material.

The at least one sealing element preferably comprises an injection moldable material and a material suitable for fuel cells or is formed from such a material.

Whenever it is mentioned in this specification and the appended claims that a first element is applied as a coating to a second element, it is to be understood that the first element is formed by an in situ coating operation on the second element. This expression does not include joining a first element manufactured separately from the second element to the second element after manufacture of the first element.

Further features and advantages of the invention are the subject of the following description and the graphic representation of exemplary embodiments.

• 1 einen schematischen Längsschnitt durch einen Randbereich einer elektrochemischen Einheit für eine elektrochemische Vorrichtung, welche eine Membran, eine erste Elektrode, eine zweite Elektrode, eine erste Gasdiffusionslage, eine zweite Gasdiffusionslage, eine Dichtung, welche ein Dichtungselement umfasst, das an die erste Elektrode, an die Membran, an die zweite Elektrode und/oder an die zweite Gasdiffusionslage angebunden ist, und eine Bipolarplatte umfasst;
• 2 einen Längsschnitt durch eine zweite Ausführungsform einer elektrochemischen Einheit für eine elektrochemische Vorrichtung, bei welcher die Dichtung zwei Dichtungselemente umfasst, wobei ein Gasdiffusionslagen-Dichtungselement an die erste Gasdiffusionslage und ein Verbund-Dichtungselement an einen elektrochemisch aktiven Verbund aus der zweiten Gasdiffusionslage, der zweiten Elektrode, der Membran und der ersten Elektrode angebunden ist;
• 3 einen Längsschnitt durch eine dritte Ausführungsform einer elektrochemischen Einheit für eine elektrochemische Vorrichtung, bei welcher ein äußerer Rand der ersten Elektrode gegenüber einem äußeren Rand der zweiten Elektrode nach innen, das heißt zum Zentrum der elektrochemischen Einheit hin, versetzt ist und das Dichtungselement an die Membran, an die zweite Elektrode und/oder an die zweite Gasdiffusionslage angebunden ist;
• 4 einen Längsschnitt durch eine vierte Ausführungsform einer elektrochemischen Einheit für eine elektrochemische Vorrichtung, bei welcher die Dichtung zwei Dichtungselemente umfasst, wobei ein Gasdiffusionslagen-Dichtungselement an die erste Gasdiffusionslage und optional an die erste Elektrode angebunden ist und ein Membran-Dichtungselement an die Membran und optional an die zweite Elektrode und/oder an die zweite Gasdiffusionslage angebunden ist;
• 5 einen Längsschnitt durch eine fünfte Ausführungsform einer elektrochemischen Einheit für eine elektrochemische Vorrichtung, bei welcher ein äußerer Rand der zweiten Elektrode und ein äußerer Rand der zweiten Gasdiffusionslage gegenüber einem äußeren Rand der ersten Elektrode nach innen, das heißt zum Zentrum der elektrochemischen Einheit hin, versetzt sind, das Dichtungselement an die zweite Gasdiffusionslage und optional an die zweite Elektrode angebunden ist und das Dichtungselement mit einem Membran-Abdichtbereich an der Membran der elektrochemischen Einheit abdichtend anliegt;
• 6 einen Längsschnitt durch eine sechste Ausführungsform einer elektrochemischen Einheit für eine elektrochemische Vorrichtung, bei welcher die Dichtung zwei Dichtungselemente umfasst, wobei ein erstes Gasdiffusionslagen-Dichtungselement an die erste Gasdiffusionslage, an die erste Elektrode und an einen ersten Teil der Membran angebunden ist und ein zweites Gasdiffusionslagen-Dichtungselement an die zweite Gasdiffusionslage, an die zweite Elektrode und an einen zweiten Teil der Membran angebunden ist;
• 7 einen Längsschnitt durch eine siebte Ausführungsform einer elektrochemischen Einheit für eine elektrochemische Vorrichtung, bei welcher das Dichtungselement mit einem Bipolarplatten-Abdichtbereich an eine Bipolarplatte einer der elektrochemischen Einheit benachbarten weiteren elektrochemischen Einheit angebunden ist, beispielsweise durch Anspritzen;
• 8 einen Längsschnitt durch eine achte Ausführungsform einer elektrochemischen Einheit für eine elektrochemische Vorrichtung, bei welcher das Dichtungselement an die Bipolarplatte der elektrochemischen Einheit angebunden ist, beispielsweise durch Anspritzen, und wobei das Dichtungselement mit einem Elektroden-Abdichtbereich an der ersten Elektrode der elektrochemischen Einheit abdichtend anliegt und mit einem Bipolarplatten-Abdichtbereich an einer Bipolarplatte einer der elektrochemischen Einheit benachbarten weiteren elektrochemischen Einheit abdichtend anliegt;
• 9 einen Längsschnitt durch eine neunte Ausführungsform einer elektrochemischen Einheit für eine elektrochemische Vorrichtung, bei welcher die Dichtung zwei Dichtungselemente umfasst, wobei ein erstes Bipolarplatten-Dichtungselement an die Bipolarplatte der elektrochemischen Einheit angebunden ist, beispielsweise durch Anspritzen, und mit einem Elektroden-Abdichtbereich an der ersten Elektrode der elektrochemischen Einheit abdichtend anliegt und wobei ein zweites Bipolarplatten-Dichtungselement an eine Bipolarplatte einer der elektrochemischen Einheit benachbarten weiteren elektrochemischen Einheit angebunden ist, beispielsweise durch Anspritzen, und mit einem zweiten Bipolarplatten-Abdichtbereich an der Bipolarplatte der elektrochemischen Einheit abdichtend anliegt;
• 10 einen Längsschnitt durch eine zehnte Ausführungsform einer elektrochemischen Einheit für eine elektrochemische Vorrichtung, bei welcher die Dichtung zwei Dichtungselemente umfasst, wobei ein erstes Bipolarplatten-Dichtungselement an die Bipolarplatte der elektrochemischen Einheit angebunden ist, beispielsweise durch Anspritzen, und mit einem Elektroden-Abdichtbereich an der ersten Elektrode der elektrochemischen Einheit abdichtend anliegt und mit einem Bipolarplatten-Abdichtbereich an einer Bipolarplatte einer der elektrochemischen Einheit benachbarten weiteren elektrochemischen Einheit abdichtend anliegt, und wobei ein zweites Bipolarplatten-Dichtungselement an eine Bipolarplatte einer der elektrochemischen Einheit benachbarten weiteren elektrochemischen Einheit angebunden ist, beispielsweise durch Anspritzen, wobei das zweite Bipolarplatten-Dichtungselement in eine Nut des ersten Bipolarplatten-Dichtungselements eingreift;
• 11 einen Längsschnitt durch eine elfte Ausführungsform einer elektrochemischen Einheit für eine elektrochemische Vorrichtung, bei welcher die Dichtung zwei Dichtungselemente umfasst, wobei ein erstes Bipolarplatten-Dichtungselement an die Bipolarplatte der elektrochemischen Einheit angebunden ist, beispielsweise durch Anspritzen, und mit einem Membran-Abdichtbereich an der Membran der elektrochemischen Einheit abdichtend anliegt, und wobei ein zweites Bipolarplatten-Dichtungselement an eine Bipolarplatte einer der elektrochemischen Einheit benachbarten weiteren elektrochemischen Einheit angebunden ist, beispielsweise durch Anspritzen, und mit einem Bipolarplatten-Abdichtbereich an der Bipolarplatte der elektrochemischen Einheit abdichtend anliegt;
• 12 einen Längsschnitt durch eine zwölfte Ausführungsform einer elektrochemischen Einheit für eine elektrochemische Vorrichtung, bei welcher die Dichtung zwei Dichtungselemente umfasst, wobei ein erstes Bipolarplatten-Dichtungselement an die Bipolarplatte der elektrochemischen Einheit angebunden ist, beispielsweise durch Anspritzen, und mit einem Membran-Abdichtbereich an der Membran der elektrochemischen Einheit abdichtend anliegt und mit einem Bipolarplatten-Abdichtbereich an der Bipolarplatte einer der elektrochemischen Einheit benachbarten weiteren elektrochemischen Einheit abdichtend anliegt, und wobei ein zweites Bipolarplatten-Dichtungselement an die Bipolarplatte der der elektrochemischen Einheit benachbarten weiteren elektrochemischen Einheit angebunden ist, beispielsweise durch Anspritzen, und in eine Nut des ersten Bipolarplatten-Dichtungselements eingreift;
• 13 einen Längsschnitt durch eine dreizehnte Ausführungsform einer elektrochemischen Einheit für eine elektrochemische Vorrichtung, bei welcher das Dichtungselement an die Bipolarplatte und an die erste Gasdiffusionslage der elektrochemischen Einheit angebunden ist, beispielsweise durch Anspritzen, und mit einem Elektroden-Abdichtbereich an der ersten Elektrode der elektrochemischen Einheit abdichtend anliegt und mit einem Bipolarplatten-Abdichtbereich an einer Bipolarplatte einer der elektrochemischen Einheit benachbarten weiteren elektrochemischen Einheit abdichtend anliegt;
• 14 einen Längsschnitt durch eine vierzehnte Ausführungsform einer elektrochemischen Einheit für eine elektrochemische Vorrichtung, bei welcher das Dichtungselement an die Bipolarplatte, an die erste Gasdiffusionslage und an die erste Elektrode der elektrochemischen Einheit angebunden ist, beispielsweise durch Anspritzen, und mit einem Membran-Abdichtbereich an der Membran der elektrochemischen Einheit abdichtend anliegt und mit einem Bipolarplatten-Abdichtbereich an einer Bipolarplatte einer der elektrochemischen Einheit benachbarten weiteren elektrochemischen Einheit abdichtend anliegt;
• 15 einen Längsschnitt durch eine fünfzehnte Ausführungsform einer elektrochemischen Einheit für eine elektrochemische Vorrichtung, bei welcher das Dichtungselement an die Bipolarplatte der elektrochemischen Einheit angebunden ist, beispielsweise durch Anspritzen, und mit einem Membran-Abdichtbereich an der Membran der elektrochemischen Einheit abdichtend anliegt und mit einem Bipolarplatten-Abdichtbereich an einer Bipolarplatte einer der elektrochemischen Einheit benachbarten weiteren elektrochemischen Einheit abdichtend anliegt, wobei die erste Elektrode als eine auf die erste Gasdiffusionslage applizierte Beschichtung ausgebildet ist;
• 16 einen Längsschnitt durch eine sechzehnte Ausführungsform einer elektrochemischen Einheit für eine elektrochemische Vorrichtung, bei welcher die elektrochemische Einheit zusätzlich ein Subgasket umfasst, das an eine Elektrode der elektrochemischen Einheit angebunden ist, beispielsweise durch Verklebung oder Heißverpressung, und bei welcher das Dichtungselement an die Bipolarplatte der elektrochemischen Einheit angebunden ist, beispielsweise durch Anspritzen, und mit einem Subgasket-Abdichtbereich an dem Subgasket abdichtend anliegt und mit einem Bipolarplatten-Abdichtbereich an einer Bipolarplatte einer der elektrochemischen Einheit benachbarten weiteren elektrochemischen Einheit abdichtend anliegt;
• 17 einen Längsschnitt durch eine siebzehnte Ausführungsform einer elektrochemischen Einheit für eine elektrochemische Vorrichtung, bei welcher die elektrochemische Einheit zusätzlich ein Subgasket umfasst, das an die Membran der elektrochemischen Einheit angebunden ist, beispielsweise durch Verklebung oder Heißverpressung, und bei welcher das Dichtungselement an die Bipolarplatte der elektrochemischen Einheit angebunden ist, beispielsweise durch Anspritzen, und mit einem Subgasket-Abdichtbereich abdichtend an dem Subgasket anliegt und mit einem Bipolarplatten-Abdichtbereich an einer Bipolarplatte einer der elektrochemischen Einheit benachbarten weiteren elektrochemischen Einheit abdichtend anliegt;
• 18 einen Längsschnitt durch eine achtzehnte Ausführungsform einer elektrochemischen Einheit für eine elektrochemische Vorrichtung, bei welcher die elektrochemische Einheit zusätzlich ein Subgasket umfasst, das an eine Elektrode der elektrochemischen Einheit angebunden ist, beispielsweise durch Verklebung oder Heißverpressung, und bei welcher die Dichtung zwei Dichtungselemente umfasst, wobei ein erstes Bipolarplatten-Dichtungselement an die Bipolarplatte der elektrochemischen Einheit angebunden ist, beispielsweise durch Anspritzen, und mit einem ersten Subgasket-Abdichtbereich an dem Subgasket abdichtend anliegt, und wobei ein zweites Bipolarplatten-Dichtungselement an eine Bipolarplatte einer der elektrochemischen Einheit benachbarten weiteren elektrochemischen Einheit angebunden ist, beispielsweise durch Anspritzen, und mit einem zweiten Subgasket-Abdichtbereich an dem Subgasket abdichtend anliegt;
• 19 einen Längsschnitt durch eine neunzehnte Ausführungsform einer elektrochemischen Einheit für eine elektrochemische Vorrichtung, bei welcher die elektrochemische Einheit zusätzlich ein Subgasket umfasst, das an die Membran der elektrochemischen Einheit angebunden ist, beispielsweise durch Verklebung oder Heißverpressung, und bei welcher die Dichtung zwei Dichtungselemente umfasst, wobei ein erstes Bipolarplatten-Dichtungselement an die Bipolarplatte der elektrochemischen Einheit angebunden ist, beispielsweise durch Anspritzen, und mit einem ersten Subgasket-Abdichtbereich an dem Subgasket abdichtend anliegt, und wobei ein zweites Bipolarplatten-Dichtungselement an eine Bipolarplatte einer der elektrochemischen Einheit benachbarten weiteren elektrochemischen Einheit angebunden ist, beispielsweise durch Anspritzen, und mit einem zweiten Subgasket-Abdichtbereich an dem Subgasket abdichtend anliegt;
• 20 einen Längsschnitt durch eine zwanzigste Ausführungsform einer elektrochemischen Einheit für eine elektrochemische Vorrichtung, bei welcher die elektrochemische Einheit zusätzlich ein Subgasket umfasst, das an eine Elektrode der elektrochemischen Einheit angebunden ist, beispielsweise durch Verklebung oder Heißverpressung, wobei das Dichtungselement an das Subgasket angebunden ist, beispielsweise durch Anspritzen, und mit einem ersten Bipolarplatten-Abdichtbereich an der Bipolarplatte der elektrochemischen Einheit abdichtend anliegt und mit einem zweiten Bipolarplatten-Abdichtbereich an einer Bipolarplatte einer der elektrochemischen Einheit benachbarten weiteren elektrochemischen Einheit abdichtend anliegt; und
• 21 einen Längsschnitt durch eine einundzwanzigste Ausführungsform einer elektrochemischen Einheit für eine elektrochemische Vorrichtung, bei welcher die elektrochemische Einheit zusätzlich ein Subgasket umfasst, das an die Membran der elektrochemischen Einheit angebunden ist, beispielsweise durch Verklebung oder Heißverpressung, und bei welcher das Dichtungselement an das Subgasket angebunden ist, beispielsweise durch Anspritzen, und mit einem ersten Bipolarplatten-Abdichtbereich an der Bipolarplatte der elektrochemischen Einheit abdichtend anliegt und mit einem zweiten Bipolarplatten-Abdichtbereich an der Bipolarplatte einer der elektrochemischen Einheit benachbarten weiteren elektrochemischen Einheit abdichtend anliegt.

In the drawings show:

• 1 a schematic longitudinal section through an edge region of an electrochemical unit for an electrochemical device, which has a membrane, a first electrode, a second electrode, a first gas diffusion layer, a second gas diffusion layer, a gasket comprising a gasket member bonded to the first electrode, to the membrane, to the second electrode and/or to the second gas diffusion layer, and a bipolar plate;
• 2 a longitudinal section through a second embodiment of an electrochemical unit for an electrochemical device, in which the seal comprises two sealing elements, a gas diffusion layer sealing element being attached to the first gas diffusion layer and a composite sealing element being attached to an electrochemically active composite made up of the second gas diffusion layer, the second electrode, the membrane and the first electrode is attached;
• 3 a longitudinal section through a third embodiment of an electrochemical unit for an electrochemical device, in which an outer edge of the first electrode is offset inwards relative to an outer edge of the second electrode, i.e. towards the center of the electrochemical unit, and the sealing element is attached to the membrane, is connected to the second electrode and/or to the second gas diffusion layer;
• 4 a longitudinal section through a fourth embodiment of an electrochemical unit for an electrochemical device, in which the seal comprises two sealing elements, wherein a gas diffusion layer sealing element is connected to the first gas diffusion layer and optionally to the first electrode and a membrane sealing element to the membrane and optionally to the second electrode and/or is connected to the second gas diffusion layer;
• 5 a longitudinal section through a fifth embodiment of an electrochemical unit for an electrochemical device, in which an outer edge of the second electrode and an outer edge of the second gas diffusion layer are offset inwards relative to an outer edge of the first electrode, i.e. towards the center of the electrochemical unit , the sealing element is connected to the second gas diffusion layer and optionally to the second electrode and the sealing element bears in a sealing manner with a membrane sealing area on the membrane of the electrochemical unit;
• 6 a longitudinal section through a sixth embodiment of an electrochemical unit for an electrochemical device, in which the seal comprises two sealing elements, a first gas diffusion layer sealing element being connected to the first gas diffusion layer, to the first electrode and to a first part of the membrane and a second gas diffusion layer - sealing element is bonded to the second gas diffusion layer, to the second electrode and to a second part of the membrane;
• 7 a longitudinal section through a seventh embodiment of an electrochemical unit for an electrochemical device, in which the sealing element is connected with a bipolar plate sealing area to a bipolar plate of the electrochemical unit adjacent further electrochemical unit, for example by injection molding;
• 8th a longitudinal section through an eighth embodiment of an electrochemical unit for an electrochemical device, in which the sealing element is connected to the bipolar plate of the electrochemical unit, for example by injection molding, and the sealing element with an electrode sealing area on the first electrode of the electrochemical unit rests sealingly and a bipolar plate sealing region sealingly abuts a bipolar plate of a further electrochemical unit adjacent to the electrochemical unit;
• 9 a longitudinal section through a ninth embodiment of an electrochemical unit for an electrochemical device, in which the seal comprises two sealing elements, wherein a first bipolar plate sealing element is connected to the bipolar plate of the electrochemical unit, for example by molding, and with an electrode sealing area on the first Electrode of the electrochemical unit is in sealing contact and a second bipolar plate sealing element is connected to a bipolar plate of a further electrochemical unit adjacent to the electrochemical unit, for example by injection molding, and a second bipolar plate sealing area is in sealing contact with the bipolar plate of the electrochemical unit;
• 10 a longitudinal section through a tenth embodiment of an electrochemical unit for an electrochemical device, in which the seal comprises two sealing elements, wherein a first bipolar plate sealing element is connected to the bipolar plate of the electrochemical unit, for example by molding, and with an electrode sealing area on the first Electrode of the electrochemical unit sealingly abuts and with a bipolar plate sealing area to a bipolar plate of one of the electrodes mixing unit is in sealing contact with the further electrochemical unit adjacent to it, and wherein a second bipolar plate sealing element is connected to a bipolar plate of a further electrochemical unit adjacent to the electrochemical unit, for example by injection molding, wherein the second bipolar plate sealing element engages in a groove of the first bipolar plate sealing element;
• 11 a longitudinal section through an eleventh embodiment of an electrochemical unit for an electrochemical device, in which the seal comprises two sealing elements, wherein a first bipolar plate sealing element is connected to the bipolar plate of the electrochemical unit, for example by injection molding, and with a membrane sealing area on the membrane of the electrochemical unit, and wherein a second bipolar plate sealing element is connected to a bipolar plate of a further electrochemical unit adjacent to the electrochemical unit, for example by injection molding, and with a bipolar plate sealing area on the bipolar plate of the electrochemical unit in sealing contact;
• 12 a longitudinal section through a twelfth embodiment of an electrochemical unit for an electrochemical device, in which the seal comprises two sealing elements, wherein a first bipolar plate sealing element is connected to the bipolar plate of the electrochemical unit, for example by molding, and with a membrane sealing area on the membrane the electrochemical unit is in sealing contact and a bipolar plate sealing area is in sealing contact with the bipolar plate of a further electrochemical unit adjacent to the electrochemical unit, and wherein a second bipolar plate sealing element is connected to the bipolar plate of the further electrochemical unit adjacent to the electrochemical unit, for example by injection molding, and engages a groove of the first bipolar plate gasket;
• 13 a longitudinal section through a thirteenth embodiment of an electrochemical unit for an electrochemical device, in which the sealing element is connected to the bipolar plate and to the first gas diffusion layer of the electrochemical unit, for example by molding, and with an electrode sealing area on the first electrode of the electrochemical unit sealing abuts and sealingly abuts with a bipolar plate sealing region on a bipolar plate of a further electrochemical unit adjacent to the electrochemical unit;
• 14 a longitudinal section through a fourteenth embodiment of an electrochemical unit for an electrochemical device, in which the sealing element is connected to the bipolar plate, to the first gas diffusion layer and to the first electrode of the electrochemical unit, for example by injection molding, and with a membrane sealing area on the membrane sealingly abuts the electrochemical unit and sealingly abuts with a bipolar plate sealing area against a bipolar plate of a further electrochemical unit adjacent to the electrochemical unit;
• 15 a longitudinal section through a fifteenth embodiment of an electrochemical unit for an electrochemical device, in which the sealing element is connected to the bipolar plate of the electrochemical unit, for example by molding, and with a membrane sealing area on the membrane of the electrochemical unit rests sealingly and with a bipolar plate The sealing region is in sealing contact with a bipolar plate of a further electrochemical unit that is adjacent to the electrochemical unit, the first electrode being in the form of a coating applied to the first gas diffusion layer;
• 16 a longitudinal section through a sixteenth embodiment of an electrochemical unit for an electrochemical device, in which the electrochemical unit additionally comprises a subgasket which is connected to an electrode of the electrochemical unit, for example by gluing or hot pressing, and in which the sealing element is attached to the bipolar plate of the electrochemical Unit is connected, for example by injection molding, and with a subgasket sealing area on the subgasket and sealingly abuts with a bipolar plate sealing area on a bipolar plate of the electrochemical unit adjacent further electrochemical unit;
• 17 a longitudinal section through a seventeenth embodiment of an electrochemical unit for an electrochemical device, in which the electrochemical unit additionally comprises a subgasket which is connected to the membrane of the electrochemical unit, for example by gluing or hot pressing, and in which the sealing element is connected to the bipolar plate of the electrochemical unit, for example by injection molding, and with a subgasket sealing area rests sealingly on the subgasket and with a bipolar plate sealing area on a bipolar plate of a further electrochemical unit adjacent to the electrochemical unit;
• 18 a longitudinal section through an eighteenth embodiment of an electrochemical unit for an electrochemical device, in which the electrochemical unit additionally comprises a subgasket which is connected to an electrode of the electrochemical unit, for example by gluing or hot pressing, and in which the seal comprises two sealing elements, wherein a first bipolar plate sealing element is connected to the bipolar plate of the electrochemical unit, for example by injection molding, and a first subgasket sealing area is in sealing contact with the subgasket, and a second bipolar plate sealing element is connected to a bipolar plate of a further electrochemical unit adjacent to the electrochemical unit is, for example by injection molding, and with a second subgasket sealing area rests sealingly on the subgasket;
• 19 a longitudinal section through a nineteenth embodiment of an electrochemical unit for an electrochemical device, in which the electrochemical unit additionally comprises a subgasket which is connected to the membrane of the electrochemical unit, for example by gluing or hot pressing, and in which the seal comprises two sealing elements, wherein a first bipolar plate sealing element is connected to the bipolar plate of the electrochemical unit, for example by injection molding, and a first subgasket sealing area is in sealing contact with the subgasket, and a second bipolar plate sealing element is connected to a bipolar plate of a further electrochemical unit adjacent to the electrochemical unit is, for example by injection molding, and with a second subgasket sealing area rests sealingly on the subgasket;
• 20 a longitudinal section through a twentieth embodiment of an electrochemical unit for an electrochemical device, in which the electrochemical unit additionally comprises a subgasket which is connected to an electrode of the electrochemical unit, for example by gluing or hot pressing, the sealing element being connected to the subgasket, for example by injection molding, and with a first bipolar plate sealing area sealingly abuts the bipolar plate of the electrochemical unit and with a second bipolar plate sealing area sealingly abuts a bipolar plate of a further electrochemical unit adjacent to the electrochemical unit; and
• 21 a longitudinal section through a twenty-first embodiment of an electrochemical unit for an electrochemical device, in which the electrochemical unit additionally comprises a subgasket which is connected to the membrane of the electrochemical unit, for example by gluing or hot pressing, and in which the sealing element is connected to the subgasket , for example by injection molding, and with a first bipolar plate sealing area on the bipolar plate of the electrochemical unit rests sealingly and with a second bipolar plate sealing area on the bipolar plate of an electrochemical unit adjacent further electrochemical unit rests sealingly.

Identical or functionally equivalent elements are denoted by the same reference symbols in all figures.

An electrochemical unit, designated as a whole by 100, of which 1 a longitudinal section through an outer edge region thereof is shown, for example, as a fuel cell 102 is formed.

A stack of such electrochemical units 102 is formed from a plurality of electrochemical units 100 which follow one another along a stacking direction (z-direction) 104 .

The stack of electrochemical units 100, in particular a fuel cell stack, forms part of an electrochemical device 106, which is used to convert chemical reaction energy, which is produced when a fuel reacts with an oxidizing agent, into electrical energy. Hydrogen, alcohol, in particular methanol, butane or natural gas are particularly suitable as fuels.

Preferably, the fuel cell 102 is a polymer electrolyte fuel cell configured as a low temperature fuel and is typically operated at an operating temperature in the range of about 60°C to about 120°C.

Each of the electrochemical units 100 includes an electrochemically active unit 108 in which the electrochemical reactions take place during operation of the electrochemical device.

The electrochemically active unit 108 comprises a first electrode 110, a second electrode 112 and a membrane 114 arranged between the two electrodes 110 and 112.

For example, it can be provided that the first electrode 110 is designed as a cathode 116 at which oxygen is reduced during operation of the electrochemical device 106 .

Provision can furthermore be made, for example, for the second electrode 112 to be in the form of an anode 118 at which hydrogen is oxidized during operation of the electrochemical device 106 .

However, it can also be provided that the first electrode 110 is in the form of an anode and the second electrode 112 is in the form of a cathode 116 . This applies to the in 1 embodiment shown and also for all other embodiments of electrochemical units 100 described below and/or shown in the drawing.

The membrane 114 serves to conduct protons from the anode 118 to the cathode 116.

The membrane 114 can be constructed in multiple layers.

Preferably, at least one of the layers of the membrane 114 is formed as a composite layer, which preferably includes an ionomer material.

The electrochemical unit 100 further includes a first gas diffusion layer 120 disposed adjacent to the first electrode 110 and a second gas diffusion layer 122 disposed adjacent to the second electrode 112 .

The gas diffusion layers 120 and 122 serve to transport gaseous media (oxidant on the cathode side; fuel gas on the anode side) to the first electrode 110 and to the second electrode 112.

Furthermore, the gas diffusion layers 120 and 122 have electrical conductivity.

The first gas diffusion layer 120 and/or the second gas diffusion layer 122 can be formed from non-woven carbon fibers (so-called carbon papers), for example.

The carbon fibers can be made hydrophobic by coating them with polytetrafluoroethylene (PTFE).

The first gas diffusion layer 120 and/or the second gas diffusion layer 122 may each comprise a microporous layer (MPL).

The microporous layer preferably faces the electrochemically active unit 108 .

Furthermore, each electrochemical unit 100 comprises a bipolar plate 124 which is arranged adjacent to the first gas diffusion layer 120 of the electrochemical unit 100 in question.

A bipolar plate 124 ′ of a further electrochemical unit 100 ′ of the electrochemical device 106 adjacent to the electrochemical unit 100 is arranged adjacent to the second gas diffusion layer 122 of the electrochemical unit 100 .

The bipolar plates 124, 124' separate the gas spaces of electrochemical units 100, 100' that follow one another along the stacking direction 104.

Furthermore, the bipolar plates 124, 124' serve to connect electrochemical units 100, 100' that follow one another in the stacking direction 104 in an electron-conductive manner and thus to connect them electrically in series.

The bipolar plates 124, 124' are preferably formed from a metallic material. In principle, however, it can also be provided that the bipolar plates 124, 124' are formed from a graphite material.

Each of the bipolar plates 124, 124' can be multi-layered, in particular two-layered.

In this case, each bipolar plate 124, 124′ preferably encloses an inner cavity through which a cooling medium can flow, for example in the operating state of the electrochemical device 106 .

Each of the bipolar plates 124, 124' has a gas flow field on each of its sides, namely an anode-side flow field facing an anode 118 of an electrochemical unit 100, through which a fuel gas can flow during operation of the electrochemical device 106, and a cathode 116 an electrochemical unit 100 facing the cathode-side flow field, through which an oxidizing agent can flow during the operation of the electrochemical device 106 .

To ensure a fluid-tight seal of these gas flow fields from the environment of the electrochemical unit 100 and the electrochemical device 106, from one another and/or from medium channels (not shown), which pass through the electrochemical device 106 parallel to the stacking direction 104 and the supply of fuel gas and oxidizing agent serve to the electrochemical units 100 or the removal of reaction products from the electrochemical units 100, each electrochemical unit 100 further comprises a seal 126, which comprises at least one sealing element 128.

The sealing member 128 is preferably formed from an elastomeric material.

The sealing element 128 runs parallel to an outer edge 130 of the membrane 114, parallel to an outer edge 132 of the first electrode 110, parallel to an outer edge 134 of the second electrode 112, parallel to an outer edge 136 of the first gas diffusion layer 120 and/or parallel to an outer edge 138 of the second gas diffusion layer 122 of the electrochemical unit 100.

The sealing element 128 preferably runs along the circumference of the electrochemical unit 100 and is preferably closed in the form of a ring.

How out 1 As can be seen, the sealing member 128 is bonded to the second gas diffusion layer 122, to the second electrode 112, to the membrane 114 and to the first electrode 110. FIG.

The sealing element 128 is preferably bonded to the second gas diffusion layer 122, to the second electrode 112, to the membrane 114 and to the first electrode 110, for example by injection molding.

The sealing element 128 preferably comprises a connection area 140 which extends into the second gas diffusion layer 122 .

The porous material from which the second gas diffusion layer 122 is formed is infiltrated in this connection region 140 by the sealing material from which the sealing element 128 is formed.

The sealing element 128 comprises a bipolar plate sealing region 148 with which the sealing element 128 rests sealingly on the bipolar plate 124 of the electrochemical unit 100 when the electrochemical unit 100 is in the assembled state.

In principle, it can be provided that the bipolar plate sealing area 148 bears with a substantially flat sealing surface against a likewise substantially flat sealing surface 150 of the bipolar plate 124 of the electrochemical unit 100 .

However, the bipolar plate sealing area 148 preferably has one, two or more sealing lips 152 with which the bipolar plate sealing area 148 bears sealingly against the bipolar plate 124 of the electrochemical unit 100 when the electrochemical unit 100 is in the assembled state.

Furthermore, the sealing element 128 comprises a further bipolar plate sealing region 154 which faces away from the bipolar plate 124 of the electrochemical unit 100 in the assembled state of the electrochemical unit 100 and with which the sealing element 128 in the assembled state of the electrochemical unit 100 on the bipolar plate 124′ of the adjacent electrochemical unit 100′. of the electrochemical device 106 in a sealing manner.

In principle, it can be provided that the additional bipolar plate sealing area 154 of the sealing element 128 has an essentially flat sealing surface, with which the additional bipolar plate sealing area 154 in the assembled state of the electrochemical unit 100 can be connected to an also essentially flat sealing surface 150 ′ of the bipolar plate 124 ′. the adjacent electrochemical unit 100' sealingly abuts.

However, the further bipolar plate sealing area 154 preferably has one, two or more sealing lips 156, with which the further bipolar plate sealing area 154 in the assembled state of the electrochemical unit 100 rests sealingly on the bipolar plate 124′ of the adjacent electrochemical unit 100′.

The sealing element 128 of the seal 126 of the electrochemical unit 100 is preferably formed in an injection molding process on an electrochemically active composite 158 which comprises the second gas diffusion layer 122, the second electrode 112, the membrane 114 and the first electrode 110.

For this purpose, the electrochemically active composite 158 is placed in an injection mold - preferably a multi-part one - and a cavity remaining in the injection mold is filled with the initially flowable sealing material of the sealing element 128, with this sealing material penetrating in particular into the area of the second gas diffusion layer 122, which later becomes the connection area 140 of the sealing element 128 forms.

After the (at least partial) curing of the sealing material of the sealing element 128, the injection mold is opened and the unit of the electrochemically active composite 158 and the sealing element 128 molded onto the same is removed.

In this embodiment, the first electrode 110, the membrane 114, the second electrode 112 and the second gas diffusion layer 122 of the electrochemical unit 100 form an electrochemically active composite 158 in which the second electrode 112 as a coating applied to the second gas diffusion layer 122, the membrane 114 is formed as a coating applied to the second electrode 112 and the first electrode 110 is formed as a coating applied to the membrane 114 .

Such an electrochemically active unit 108, which is formed directly on a gas diffusion layer by one or more coating processes, is referred to as a “direct MEA”.

• Ein Elektrodenmaterial wird auf die zweite Gasdiffusionslage 122 aufgebracht, beispielsweise mittels einer Sprühbeschichtung. Dabei bildet die zweite Gasdiffusionslage 122 ein Substrat für die zweite Elektrode 112.

The electrochemically active composite 158 can be produced, for example, as follows:

• An electrode material is applied to the second gas diffusion layer 122, for example by means of a spray coating. The second gas diffusion layer 122 forms a substrate for the second electrode 112.

To apply the electrode material, an application device can be moved over a surface of the second gas diffusion layer 122 . As an alternative to this, the application device can be arranged in a stationary manner and the second gas diffusion layer 122 can be moved relative to the application device.

After the formation of the second electrode 112 on the second gas diffusion layer 122, a membrane material is applied to a surface area of the second electrode 112 by means of a further application device, whereupon the membrane 114 forms on this surface.

The membrane material can be applied to the second electrode 112 by means of a spray coating method, for example.

The arrangement of the second gas diffusion layer 122 and the second electrode 112 forms a substrate for the membrane 114.

The membrane material can be applied, for example, in the form of a nanorod ionomer dispersion.

Such a nanorod-ionomer dispersion is made, for example, by dispersing nanorods in a liquid medium comprising an ionomer component and a dispersant.

The nanorods are provided, for example, by crushing a nanofiber material.

The nanofiber material can be provided by means of an electrospinning process, for example. Electrospinning processes for nanofibers made from polymer materials are described, for example, in the article by H. Fong et al.: "Beaded nanofibers formed during electrospinning", published in: Polymer, Vol. 40 (1999), pages 4585 to 4592.

• ein Oxid, vorzugsweise Zeroxid und/oder ein Übergangsmetalloxid, insbesondere Titandioxid und/oder Manganoxid; und/oder
• ein Polymermaterial, insbesondere ein hydrophobes Polymer, beispielsweise Polytetrafluorethylen (PTFE), Polyvinylidenfluorid (PVDF), Polybenzimidazol (PBI), ein Polyolefin, beispielsweise Polyethylen (PE) und/oder Polypropylen (PP), und/oder Polyetheretherketon (PEEK), oder ein hydrophiles Polymer, beispielsweise Polyvinylpyrrolidon (PVP).

A suitable nanofiber material includes, for example, one or more of the following materials:

• an oxide, preferably cerium oxide and/or a transition metal oxide, in particular titanium dioxide and/or manganese oxide; and or
• a polymer material, in particular a hydrophobic polymer, for example polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polybenzimidazole (PBI), a polyolefin, for example polyethylene (PE) and/or polypropylene (PP), and/or polyetheretherketone (PEEK), or a hydrophilic polymer, e.g. polyvinylpyrrolidone (PVP).

In the present description, nanorods are structures whose extension in a preferred direction is greater by a factor of 100 or more than their extension in the other spatial directions, which are aligned perpendicular to the preferred direction, the extensions in these other spatial directions being a maximum of 3000 nm or be less. The term nanorods also includes so-called nanowires (nanowires) and so-called nanowhiskers.

The nanofiber material is provided, for example, as a fiber body, preferably as a tangled fabric, as a fleece and/or as a fiber mat.

The ionomer component of the liquid medium in which the nanorods are dispersed preferably comprises at least one polymer having one or more sulfonate functionalities. A typical example of such ionomer components is the perfluorinated copolymer available under the trademark ^Nafion® .

The liquid medium can be used as a dispersing agent, for example, an alcohol, an alcohol mixed or contain an alcohol-water mixture, for example methanol, ethanol, 2-propanol or 1-butanol, mixtures of these alcohols or mixtures of these alcohols with water.

To form membrane 114, the composite layer formed during and/or after application of the nanorod ionomer dispersion is crosslinked. During crosslinking, a chemical reaction of molecules of a polymer of a nanorod with molecules of a polymer of another nanorod takes place, with the nanorods having to have a spatial contact point for crosslinking.

In addition or as an alternative to this, a chemical reaction of molecules of a polymer of the ionomer component with other molecules of a polymer of the ionomer component and/or a chemical reaction with molecules of a polymer of the nanorods takes place.

The chemical crosslinking reaction is started by a heat treatment and/or a treatment with electromagnetic radiation, for example with radiation in the ultraviolet range.

To form the crosslinking, crosslinking agents that can react with a material of the nanorods can be provided for the reaction before the production of the nanofiber material and/or after the formation of the composite layer, for example by immersing the composite layer in a crosslinking agent solution. Examples of suitable crosslinking agents for crosslinking nanorods which comprise PVDF are di-, tri- or polyamines, in particular primary diamines.

A dialdehyde, in particular glutaraldehyde, or a dibromo compound, in particular (α,α′)-dibromo-para-xylene, or a diiodo compound, in particular diiodoctane, for example 1,8-diiodoctane, are suitable for crosslinking nanorods which comprise PBI , as a crosslinking agent.

After the formation and crosslinking of the composite layer, which leads to the formation of the membrane 114, the first electrode 110 is applied to the membrane 114 by means of an application device that is moved relative to a surface of the membrane 114.

This completes the production of the electrochemically active composite 158, which comprises the second gas diffusion layer 122, the second electrode 112, the membrane 114 and the first electrode 110.

An example of the production of such an electrochemically active composite 158 is given in Section 2.1 of the article by M. Breitwieser et al.: "A fully spray-coated fuel cell membrane electrode assembly using Aquivion ionomer with a graphene oxide/cerium oxide interlayer", Journal of Power Sources 351 (2017), pages 145 to 150.

During the assembly of the electrochemical device 106, for each electrochemical unit 100, a unit composed of an electrochemically active composite 158 and a sealing element 128, a first gas diffusion layer 120 and a bipolar plate 124 are arranged relative to one another as shown in FIG 1 can be seen, and this sequence of elements is repeated for the further electrochemical units 100' until a stack of the desired number of electrochemical units is formed.

The first gas diffusion layer 120 is inserted between the electrochemically active composite 158 and the bipolar plate 124 of a respective electrochemical unit 100, preferably without a material connection to the electrochemically active composite 158 and/or to the bipolar plate 124.

one inside 2 The second embodiment of an electrochemical unit 100 for an electrochemical device 106, which is shown in part, differs from that in 1 illustrated first embodiment in that the seal 126 comprises two sealing elements 128, namely a gas diffusion layer sealing element 160, which is connected to the first gas diffusion layer 120, for example by injection molding, and a composite sealing element 162, which is connected to the electrochemically active composite 158 , for example by injection molding.

In the assembled state of the electrochemical device 106 , the gas diffusion layer sealing element 160 bears with a preferably essentially planar sealing surface 164 against a preferably essentially planar sealing surface 166 of the composite sealing element 162 .

In the assembled state of the electrochemical device 106, the composite sealing element 162 and the gas diffusion layer sealing element 160 are pressed together by means of a clamping force, which is exerted on the electrochemical units 100 stacked on top of one another, for example by means of a clamping device (not shown) of the electrochemical device 106.

The gas diffusion layer sealing element 160 includes a bipolar plate sealing area 148, with which the gas diffusion layer sealing element 160 rests sealingly on the bipolar plate 124 of the electrochemical unit 100 in the assembled state of the electrochemical unit 100.

In principle, it can be provided that the bipolar plate sealing area 148 bears with a substantially flat sealing surface against a likewise substantially flat sealing surface 150 of the bipolar plate 124 of the electrochemical unit 100 .

However, the bipolar plate sealing area 148 preferably has one, two or more sealing lips 152 with which the bipolar plate sealing area 148 bears sealingly against the bipolar plate 124 of the electrochemical unit 100 when the electrochemical unit 100 is in the assembled state.

The gas diffusion layer sealing element 160 of the gasket 126 of the electrochemical assembly 100 is preferably formed on the first gas diffusion layer 120 in an injection molding process. For this purpose, the first gas diffusion layer 120 is placed in a - preferably multi-part - injection mold and a cavity remaining in the injection mold is filled with the initially flowable sealing material of the gas diffusion layer sealing element 160, with this sealing material penetrating into an area of the first gas diffusion layer 120 which later becomes a connection area 140 ' of the gas diffusion layer sealing member 160 forms.

After the (at least partial) curing of the sealing material of the gas diffusion layer sealing element 160, the injection mold is opened and the unit consisting of the first gas diffusion layer 120 and the gas diffusion layer sealing element 160 molded onto the same is removed.

The gas diffusion layer sealing element 160 thus preferably comprises the connection area 140 ′, which extends into the first gas diffusion layer 120 .

The porous material from which the first gas diffusion layer 120 is formed is infiltrated in this connection region 140 ′ by the sealing material from which the gas diffusion layer sealing element 160 is formed.

The composite sealing element 162 is preferably formed in an injection molding process on the electrochemically active composite 158, which comprises the second gas diffusion layer 122, the second electrode 112, the membrane 114 and the first electrode 110, preferably in the manner already described above in connection with the in 1 illustrated first embodiment of the electrochemical unit 100 has been described.

The composite sealing element 162 comprises a further bipolar plate sealing region 154, which faces away from the bipolar plate 124 of the electrochemical unit 100 when the electrochemical unit 100 is assembled, with which the composite sealing element 162 when the electrochemical unit 100 is assembled on the bipolar plate 124' one of the electrochemical Unit 100 adjacent further electrochemical unit 100 'of the electrochemical device 106 rests sealingly.

In principle, it can be provided that the additional bipolar plate sealing area 154 of the composite sealing element 162 has an essentially flat sealing surface, with which the additional bipolar plate sealing area 154 in the assembled state of the electrochemical unit 100 can be attached to a likewise essentially flat sealing surface 150 ′ of the bipolar plate 124' of the adjacent electrochemical unit 100' rests sealingly.

However, the further bipolar plate sealing area 154 preferably has one, two or more sealing lips 156, with which the further bipolar plate sealing area 154 in the assembled state of the electrochemical unit 100 rests sealingly on the bipolar plate 124′ of the adjacent electrochemical unit 100′.

Incidentally, the in 2 illustrated second embodiment of an electrochemical unit in terms of structure, function and manufacturing method with in 1 illustrated first embodiment match, to the above description reference is made to that extent.

one inside 3 The third embodiment of an electrochemical unit 100 shown in part differs from that in 1 illustrated first embodiment in that the electrochemically active composite 158, to which the sealing element 128 of the seal 126 of the electrochemical unit 100 is connected, comprises only the second gas diffusion layer 122, the second electrode 112 and the membrane 114 of the electrochemical unit 100, but not the first electrode 110.

Rather, in this embodiment, first electrode 110 is configured as a coating applied to first gas diffusion layer 120 , so that first electrode 110 and first gas diffusion layer 120 together form a second electrochemically active composite 168 of electrochemical unit 100 .

The electrode material of the first electrode 110 is applied to the first gas diffusion layer 120 by means of a spray coating, for example brought. The first gas diffusion layer 120 forms a substrate for the first electrode 110.

To apply the electrode material, an application device can be moved over a surface of the first gas diffusion layer 120 . As an alternative to this, the application device can be arranged in a stationary manner and the first gas diffusion layer 120 can be moved relative to the application device.

How out 3 As can be seen, in this embodiment of the electrochemical unit 100 the outer edge 132 of the first electrode 110 is opposite the outer edge 130 of the membrane 114, opposite the outer edge 134 of the second electrode 112 and/or opposite the outer edge 138 of the second gas diffusion layer 122 inwards, that is, towards the center of the electrochemical unit 100.

In particular, in this embodiment, the first electrode 110 is preferably not in contact with the sealing element 128 of the seal 126 of the electrochemical unit 100.

During the assembly of the electrochemical device 106, for each electrochemical unit 100, a unit made up of an electrochemically active composite 158 and a sealing element 128, a second electrochemically active composite 168 made up of the first gas diffusion layer 120 and the first electrode 110 formed thereon, and a bipolar plate 124 are so relative arranged to each other like this 3 can be seen, and this sequence of elements is repeated for the further electrochemical units 100' until a stack of the desired number of electrochemical units is formed.

The second electrochemically active composite 168 consisting of the first gas diffusion layer 120 and the first electrode 110 is inserted between the first electrochemically active composite 148 and the bipolar plate 124 of a respective electrochemical unit 100, preferably without a material connection to the first electrochemically active composite 158 and/or or with the bipolar plate 124.

Incidentally, the in 3 illustrated third embodiment of an electrochemical unit 100 in terms of structure, function and manufacturing method with in 1 illustrated first embodiment match, to the above description reference is made to that extent.

A snippet in 4 illustrated fourth embodiment of an electrochemical unit 100 differs from that in 2 illustrated second embodiment in that the electrochemically active composite 158, to which the composite sealing element 162 is connected, for example by injection molding, comprises only the second gas diffusion layer 122, the second electrode 112 and the membrane 114, but not the first electrode 110.

In this embodiment, the first electrode 110 is rather formed as a coating applied to the first gas diffusion layer 120 , so that the first electrode 110 and the first gas diffusion layer 120 together form a second electrochemically active composite 168 of the electrochemical unit 100 .

In this embodiment, the gas diffusion layer sealing element 160 is bonded to the first gas diffusion layer 120 , for example by injection molding, after the first electrode 110 has already been formed on the first gas diffusion layer 120 .

During assembly of the electrochemical device 106, for each electrochemical unit 100, an electrochemically active composite 158 and composite sealing member 162 unit, a second electrochemically active composite 168 and gas diffusion layer sealing member 160 unit, and a bipolar plate 124 are positioned relative to each other arranged like this out 4 can be seen, and this sequence of elements is repeated for the further electrochemical units 100' until a stack of the desired number of electrochemical units is formed.

The second electrochemically active composite 168 consisting of the first gas diffusion layer 120 and the first electrode 110 is inserted between the electrochemically active composite 158 and the bipolar plate 124 of a respective electrochemical unit 100, preferably without a material connection to the electrochemically active composite 158 and/or with the bipolar plate 124.

Incidentally, the in 4 illustrated fourth embodiment of an electrochemical unit 100 in terms of structure, function and manufacturing method with the in 2 illustrated second embodiment match, to the above description reference is made to that extent.

one inside 5 illustrated fifth embodiment of an electrochemical unit 100 differs from that in 1 illustrated first embodiment characterized in that the electrochemically active composite 158, to which the sealing element 128 of the seal 126 of the electrochemical unit 100 is connected for example by injection molding, only the second gas diffusion layer 122 and the second electrode 112, but not the membrane 114 and the first electrode 110.

Rather, in this embodiment, first electrode 110 and membrane 114, together with first gas diffusion layer 120, form a second electrochemically active composite 168, in which first electrode 110 is formed as a coating applied to first gas diffusion layer 120 and membrane 114 is formed as one the first electrode 110 applied coating is formed.

In this embodiment, an outer edge 138 of the second gas diffusion layer 122 and/or an outer edge 134 of the second electrode 112 is preferably opposite the outer edge 136 of the first gas diffusion layer 120, opposite the outer edge 132 of the first electrode 110 and/or opposite the outer edge 130 of the membrane 114 of the electrochemical unit 100 inwards, that is to say towards the center of the electrochemical unit 100, offset.

In this embodiment, the sealing element 128 has a membrane sealing area 170 with which the sealing element 128 rests sealingly against the membrane 114 of the second electrochemically active compound 168 in the assembled state of the electrochemical unit 100 .

The membrane sealing area 170 is preferably arranged between the connection area 140 and the further bipolar plate sealing area 154 of the sealing element 128 .

In principle, it can be provided that the membrane sealing region 170 bears in a sealing manner with an essentially flat sealing surface against a likewise essentially flat sealing surface 172 of the membrane 114 .

However, the membrane sealing area 170 preferably has one, two or more sealing lips 174 with which the membrane sealing area 170 bears sealingly against the membrane 114 of the electrochemical unit 100 in the assembled state of the electrochemical unit 100 .

During the assembly of the electrochemical device 106, for each electrochemical unit 100, a unit made up of an electrochemically active composite 158 and a sealing element 128, a second electrochemically active composite 168 made up of a first gas diffusion layer 120, the first electrode 110 formed thereon and the membrane 114 formed thereon and a bipolar plate 124 positioned relative to each other as shown 5 can be seen, and this sequence of elements is repeated for the further electrochemical units 100' until a stack of the desired number of electrochemical units is formed.

The second electrochemically active composite 168 made of the first gas diffusion layer 120, the first electrode 110 and the membrane 114 is in each case between the electrochemically active composite 158 made of the second gas diffusion layer 122 and the second electrode 112 on the one hand and the bipolar plate 124 of a respective electrochemical unit 100 on the other hand inserted, preferably without a material connection to the electrochemically active composite 158 and/or to the bipolar plate 124.

Incidentally, the in 5 illustrated fifth embodiment of an electrochemical unit 100 in terms of structure, function and manufacturing method with the in 1 illustrated first embodiment match, to the above description reference is made to that extent.

one inside 6 The sixth specific embodiment of an electrochemical unit 100 shown in detail differs from that in 4 fourth embodiment illustrated in that the electrochemically active composite 158, to which the composite sealing element 162 is attached, for example by injection molding, comprises only the second gas diffusion layer 122, the second electrode 112 and a first part 114a of the membrane 114, but not a second Part 114b of the membrane 114, the first electrode 110 and the first gas diffusion layer 120.

In this embodiment, the second part 114b of the membrane 114 forms part of the second electrochemically active composite 168 , which also includes the first electrode 110 and the first gas diffusion layer 120 . The gas diffusion layer sealing element 160 of the seal 126 is connected to this second electrochemically active composite 168, for example by injection molding.

Preferably, the first portion 114a and the second portion 114b of the membrane 114 each comprise approximately half of the membrane 114.

Unlike the in 4 In the illustrated fourth embodiment of the electrochemical unit 100, in this embodiment the outer edge 136 of the first gas diffusion layer 120 is not offset inward relative to the outer edge 138 of the second gas diffusion layer 122, i.e. towards the center of the electrochemical unit 100.

Rather, the outer edge 136 of the first gas diffusion layer 120 and the outer edge 138 of the second gas diffusion layer 122 are essentially flush with one another in this embodiment—seen along the stacking direction 104 .

It is favorable if the first electrochemically active composite 158 and the second electrochemically active composite 168 are essentially mirror-symmetrical to one another.

It is particularly favorable if the first electrochemically active composite 158 and the second electrochemically active composite 168 are configured identically to one another and when assembling the electrochemical device 106 only in two different positions, which can be converted into one another by rotation about an axis of rotation running perpendicular to the stacking direction 104 , are arranged in the electrochemical unit 100 .

In this embodiment, the first part 114a of the membrane 114 is in the form of a coating applied to the second electrode 112 .

In this embodiment, the second part 114b of the membrane 114 is formed as a coating applied to the first electrode 110 .

During assembly of the electrochemical device 106, for each electrochemical unit 100, an electrochemically active composite 158 and composite gasket 162 assembly, a second electrochemically active composite 168 and gas diffusion layer gasket 160 assembly, and a bipolar plate 124 are assembled relative to each other arranged like this out 6 can be seen, and this sequence of elements is repeated for the further electrochemical units 100' until a stack of the desired number of electrochemical units is formed.

The second electrochemically active composite 168 made up of the first gas diffusion layer 120, the first electrode 110 and the second part 114b of the membrane 114 is inserted between the first electrochemically active composite 158 and the bipolar plate 124 of a respective electrochemical unit 100, preferably without a material connection the electrochemically active compound 158 and/or with the bipolar plate 124.

Incidentally, the in 6 illustrated sixth embodiment of an electrochemical unit 100 in terms of structure, function and manufacturing method with the in 4 illustrated fourth embodiment, reference is made to the above description in this respect.

one inside 7 The seventh embodiment of an electrochemical unit 100, shown in part, differs from that in 1 illustrated first embodiment in that the sealing element 128 of the seal 126 in this embodiment does not bear with a further bipolar plate sealing region 154 in a sealing manner against a bipolar plate 124' of a further electrochemical unit 100' adjacent to the electrochemical unit 100, but is bonded to this bipolar plate 124' is, for example by spraying.

To produce the sealing element 128 on the electrochemically active composite 158 of the electrochemical unit 100, the procedure is such that the electrochemically active composite 158 is placed together with the bipolar plate 124' in a cavity of an injection mold and the space remaining in the cavity is filled by means of - initially flowable - sealing material of the sealing element 128 is filled.

After the sealing element 128 has hardened, the same is materially bonded not only to the electrochemically active composite 158, but also to the bipolar plate 124'.

Incidentally, the in 7 illustrated seventh embodiment of an electrochemical unit 100 in terms of structure, function and manufacturing method with the in 1 illustrated first embodiment match, to the above description reference is made to that extent.

one inside 8th The eighth embodiment of an electrochemical unit 100, which is shown in part, differs from that in 7 illustrated seventh embodiment in that the sealing element 128 of the seal 126 is not materially bonded to either the electrochemically active composite 158 or to the bipolar plate 124' of a further electrochemical unit 100' adjacent to the electrochemical unit 100, but is bonded to the bipolar plate 124 of the electrochemical unit 100 is, for example by spraying.

In this embodiment, the sealing element 128 preferably comprises an electrode sealing region 176 with which the sealing element 128 bears sealingly against the first electrode 110 of the electrochemical unit 100 when the electrochemical unit 100 is in the assembled state.

In principle, it can be provided that the electrode sealing area 176 rests with a substantially flat sealing surface against a likewise substantially flat sealing surface 178 of the first electrode 110 of the electrochemical unit 100 .

However, the electrode sealing area 176 preferably has one, two or more sealing lips 180 with which the electrode sealing area 176 bears in a sealing manner on the first electrode 110 of the electrochemical unit 100 .

In the manufacture of this embodiment of the electrochemical unit, the bipolar plate 124 is placed in the cavity of an injection mold and the remaining volume of the cavity is filled with the sealing material from which the sealing element 128 is formed.

A unit is thus formed from the bipolar plate 124 and the sealing element 128 .

In this embodiment, the sealing element 128 is preferably not connected to the first gas diffusion layer 120 and/or not to the second gas diffusion layer 122, in particular not connected with a material bond.

During the assembly of the electrochemical device 106, for each electrochemical unit 100, a unit comprising the bipolar plate 124 and the sealing element 128, the first gas diffusion layer 120 and the electrochemically active composite 158 are arranged relative to one another as shown 8th can be seen, and this sequence of elements is repeated for the further electrochemical units 100' until a stack of the desired number of electrochemical units is formed.

The first gas diffusion layer 120 is inserted between the bipolar plate 124 with the sealing element 128 arranged thereon on the one hand and the electrochemically active composite 158 on the other hand, preferably without a material connection to the bipolar plate 124 and/or to the electrochemically active composite 158.

Incidentally, the in 8th illustrated eighth embodiment of an electrochemical unit in terms of structure, function and manufacturing method with the in 7 illustrated seventh embodiment correspond to the above description reference is made to that extent.

one inside 9 The ninth embodiment of an electrochemical unit 100, shown in part, differs from that in 8th illustrated eighth embodiment in that the seal 126 comprises not only a sealing element 128, but also a first bipolar plate sealing element 182, which is connected to a further bipolar plate 124' of a further electrochemical unit 100' adjacent to the electrochemical unit 100 and to the bipolar plate 124 of the electrochemical assembly 100 and includes an electrode sealing member 184 bonded to bipolar plate 124 of electrochemical assembly 100 and sealingly abuts first electrode 110 of electrochemical assembly 100 .

The bipolar plate sealing element 182 is connected to the further bipolar plate 124 ′ of the electrochemical unit 100 ′ adjacent to the electrochemical unit 100 , for example by injection molding.

The bipolar plate sealing element 182 has a bipolar plate sealing region 148 with which the bipolar plate sealing element 182 bears sealingly against the bipolar plate 124 when the electrochemical unit 100 is in the assembled state.

In principle, it can be provided that the bipolar plate sealing area 148 bears with a substantially flat sealing surface against a likewise substantially flat sealing surface 150 of the bipolar plate 124 of the electrochemical unit 100 .

However, the bipolar plate sealing area 148 preferably has one, two or more sealing lips 152 with which the bipolar plate sealing area 148 bears sealingly against the bipolar plate 124 of the electrochemical unit 100 when the electrochemical unit 100 is in the assembled state.

The electrode sealing element 184 is bonded to the bipolar plate 124 of the electrochemical unit 100 by injection molding, for example.

The electrode sealing element 184 comprises an electrode sealing area 176 with which the electrode sealing element 184 bears sealingly against the first electrode 110 of the electrochemical unit 100 when the electrochemical unit 100 is in the assembled state.

In principle, it can be provided that the electrode sealing region 176 bears with a substantially flat sealing surface against a likewise substantially flat sealing surface 178 of the first electrode 110 .

However, the electrode sealing area 176 preferably has one, two or more sealing lips 180, with which the electrode sealing region 176 in the assembled state of the electrochemical unit 100 rests sealingly on the first electrode 110 of the electrochemical unit 100.

Incidentally, the in 9 illustrated ninth embodiment of an electrochemical unit 100 in terms of structure, function and manufacturing method with the in 8th illustrated eighth embodiment match, to the above description reference is made to that extent.

one inside 10 The tenth embodiment of an electrochemical unit 100, shown in part, differs from that in 8th Eighth embodiment illustrated in that the seal 126 of the electrochemical unit 100 comprises, in addition to the sealing element 128, a further sealing element 186 which is connected to a further bipolar plate 124′ of a further electrochemical unit 100′ adjacent to the electrochemical unit 100, for example by injection molding.

The first sealing element 128 and the further sealing element 186 of the seal 126 interact according to the tongue and groove principle, with the further sealing element 186 engaging in a groove 188 provided on the first sealing element 128 .

The groove 188 can be delimited laterally by two sealing lips 156 of the first sealing element 128 .

The engagement of the further sealing element 186 in the groove 188 of the first sealing element 128 achieves a particularly reliable seal by means of the seal 126 .

Incidentally, the in 10 illustrated tenth embodiment of an electrochemical unit 100 in terms of structure, function and manufacturing method with the in 8th illustrated eighth embodiment match, to the above description reference is made to that extent.

one inside 11 shown eleventh embodiment of an electrochemical unit 100 differs from that in 9 ninth embodiment shown in that the seal 126 comprises a membrane sealing element 190 instead of the electrode sealing element 184, which is connected to the bipolar plate 124 of the electrochemical unit 100 and in the assembled state of the electrochemical unit 100 sealingly on the membrane 114 of the electrochemical unit 100 applied.

To facilitate this, in this embodiment, the outer edge 132 of the first electrode 110 of the electrochemical assembly 100 is offset inwardly, ie toward the center of the electrochemical assembly 100, from the outer edge 130 of the membrane 114 of the electrochemical assembly 100 .

The membrane sealing element 190 is preferably bonded to the bipolar plate 124 of the electrochemical unit 100, for example by injection molding.

The membrane sealing element 190 comprises a membrane sealing area 170 with which the membrane sealing element 190 bears sealingly against the membrane 114 of the electrochemical unit 100 when the electrochemical unit 100 is in the assembled state.

In principle, it can be provided that the membrane sealing area 170 of the membrane sealing element 190 bears with a substantially flat sealing surface against a likewise substantially flat sealing surface 172 of the membrane 114 of the electrochemical unit 100 .

However, the membrane sealing area 170 preferably has one, two or more sealing lips 174 with which the membrane sealing area 170 bears sealingly against the membrane 114 of the electrochemical unit 100 in the assembled state of the electrochemical unit 100 .

Incidentally, the in 11 shown eleventh embodiment of an electrochemical unit 100 in terms of structure, function and manufacturing method with in 9 illustrated ninth embodiment correspond to the above description reference is made to that extent.

one inside 12 The twelfth embodiment of an electrochemical unit 100 shown in part differs from that in 10 tenth embodiment shown in that the first sealing element 128 of the seal 126 instead of an electrode sealing area 176 comprises a membrane sealing area 170 with which the sealing element 128 rests against the membrane 114 of the electrochemical unit 100 in a sealing manner.

To accommodate this, in this embodiment, the outer edge 132 of the first electrode 110 is offset inwardly, ie, toward the center of the electrochemical assembly 100, from the outer edge 130 of the membrane 114 of the electrochemical assembly.

Basically it can be provided that the membrane sealing area 170 with an im Substantially flat sealing surface rests against a likewise essentially flat sealing surface 172 of membrane 114 of electrochemical unit 100 .

However, the membrane sealing area 170 of the sealing element 128 preferably has one, two or more sealing lips 174 with which the membrane sealing area 170 bears sealingly against the membrane 114 of the electrochemical unit 100 in the assembled state of the electrochemical unit.

Incidentally, the in 12 illustrated twelfth embodiment of an electrochemical unit in terms of structure, function and manufacturing method with the in 10 illustrated tenth embodiment correspond to the above description reference is made to that extent.

one inside 13 shown thirteenth embodiment of an electrochemical unit 100 differs from that in 8th illustrated eighth embodiment characterized in that the sealing element 128 of the seal 126 is materially bonded not only to the bipolar plate 124, but also to the first gas diffusion layer 120 of the electrochemical unit 100.

The connection of the sealing element 128 to the first gas diffusion layer 120 is preferably produced by injection molding.

For this purpose, the bipolar plate 124 and the first gas diffusion layer 120 of the electrochemical unit 100 are placed in the cavity of an injection mold, and the remaining volume of the cavity is filled with the—at first flowable—sealing material, from which the sealing element 128 is then formed by curing.

The sealing material penetrates into the porous material of the first gas diffusion layer 120 in a connection area 140 ′ of the sealing element 128 , so that the first gas diffusion layer 120 is infiltrated with the sealing material of the sealing element 128 in this area.

During the assembly of the electrochemical device 106, for each electrochemical unit 100, a unit made up of the bipolar plate 124, the first gas diffusion layer 120 and the sealing element 128 and an electrochemically active composite 158 made up of the second gas diffusion layer 122, the second electrode 112, the membrane 114 and the first electrode 110 of the electrochemical unit 100 arranged relative to each other as shown 13 can be seen, and this sequence of elements is repeated for the further electrochemical units 100' until a stack of the desired number of electrochemical units is formed.

The electrochemically active composite 158 is inserted between the unit consisting of the bipolar plate 124, the first gas diffusion layer 120 and the sealing element 128 of the electrochemical unit 100 on the one hand and the bipolar plate 124' of another electrochemical unit 100' adjacent to the electrochemical unit 100, preferably without material bonding Connection to the first gas diffusion layer 120, the sealing element 128 and/or the further bipolar plate 124'.

Incidentally, the in 13 illustrated thirteenth embodiment of an electrochemical unit 100 in terms of structure, function and manufacturing method with the in 8th illustrated eighth embodiment match, to the above description reference is made to that extent.

one inside 14 The fourteenth embodiment of an electrochemical unit 100, shown in part, differs from that in 13 illustrated thirteenth embodiment in that the electrochemically active composite 158 comprises only the second gas diffusion layer 122, the second electrode 112 and the membrane 114, but not the first electrode 110.

In this embodiment, the first electrode 110 is formed as a coating applied to the first gas diffusion layer 120, so that the first gas diffusion layer 120 and the first electrode 110 of the electrochemical unit 100 together form a second electrochemically active composite 168 of the electrochemical unit 100.

In this embodiment, the sealing element 128 of the seal 126 of the electrochemical unit 100 is connected to the bipolar plate 124 and to the second electrochemically active composite 168 , ie to the first gas diffusion layer 120 and the first electrode 110 .

The sealing element 128 is preferably bonded to the bipolar plate 124, to the first gas diffusion layer 120 and to the first electrode 110, for example by injection molding.

For the production of the unit from the bipolar plate layer 124, the second electrochemically active composite 168 and the sealing element 128, the bipolar plate 124 and the second electrochemically active composite 168 are placed in the cavity of an injection mold, and the remaining volume in the cavity is filled with the - initially flowable - filled sealing material, from which the sealing element 128 is formed by curing.

Furthermore, in this embodiment, the sealing element 128 of the seal 126 comprises a membrane sealing region 170 instead of an electrode sealing region 176, with which the sealing element 128 bears sealingly against a sealing surface 172 of the membrane 114 when the electrochemical unit 100 is in the assembled state.

In order to facilitate this, in this embodiment the outer edge 132 of the first electrode 110 is offset inwardly from the outer edge 130 of the membrane 114 , ie towards the center of the electrochemical unit 100 .

When assembling the electrochemical device 106, for each electrochemical unit 100, a first electrochemically active composite 158, which comprises the second gas diffusion layer 122, the second electrode 112 and the membrane 114, and the unit made up of the bipolar plate 124, the second electrochemically active composite 168 and the sealing member 128 are positioned relative to each other as illustrated 13 can be seen, and this sequence of elements is repeated for the further electrochemical units 100' until a stack of the desired number of electrochemical units is formed.

Incidentally, the in 14 shown fourteenth embodiment of an electrochemical unit 100 in terms of structure, function and manufacturing method with the in 13 illustrated thirteenth embodiment correspond to the above description reference is made to that extent.

one inside 15 The fifteenth embodiment of an electrochemical device 100 shown as a detail differs from that in 12 illustrated twelfth embodiment in that the seal 126 of the electrochemical unit 100 comprises only the sealing element 128, which is connected to the bipolar plate 124, for example by injection molding, and in the assembled state of the electrochemical unit 100 with the bipolar plate sealing region 154 sealingly on a bipolar plate 124 'a further electrochemical unit 100' adjacent to the electrochemical unit 100 and sealingly rests with the membrane sealing region 170 on the membrane 114 of the electrochemically active compound 158, while the further sealing element 186 of the twelfth embodiment connected to the further bipolar plate 124' is in this embodiment omitted.

Incidentally, the in 15 shown fifteenth embodiment of an electrochemical unit 100 in terms of structure, function and manufacturing method with the in 12 illustrated twelfth embodiment correspond to the above description reference is made to that extent.

one inside 16 The sixteenth embodiment of an electrochemical unit 100, shown in part, differs from that in 8th Eighth embodiment illustrated in that the sealing element 128 is not in direct contact with the electrochemically active composite 158 of the electrochemical unit 100 .

In this embodiment, the electrochemical assembly 100 includes a rim reinforcement assembly or subgasket 192 bonded to the electrochemically active composite 158, such as the first electrode 110, the membrane 114, and/or the second electrode 112.

The subgasket 192 is preferably bonded to the electrochemically active composite 158 in a materially bonded manner.

For example, it can be provided that the subgasket 192 is connected to the electrochemically active composite 158, preferably to the first electrode 110, to the membrane 114 or to the second electrode 112, by gluing and/or by hot pressing.

In this embodiment, the sealing element 128 comprises one or more subgasket sealing areas 194a, 194b, wherein a first subgasket sealing area 194a can replace the electrode sealing area 176 of the eighth embodiment and a second subgasket sealing area 194b can replace the additional bipolar plate sealing area 154 of the eighth embodiment .

With the first subgasket sealing area 194a, the sealing element 128 lies in the assembled state of the electrochemical unit 100 in a sealing manner on a first area 196a of the subgasket 192, which is on the electrochemically active composite 158 of the electrochemical unit 100, for example on the first electrode 110, on the Membrane 114 or the second electrode 112 is fixed.

In the exemplary embodiment shown in the drawing, the first subgasket sealing region 194a is designed as a flat seal or as a strip seal, which has a substantially flat sealing surface 198 on a likewise im Substantially flat sealing surface 198 of the first region 196a of the subgasket 192 rests sealingly.

As an alternative to this, provision could also be made for the first subgasket sealing area 194a of the sealing element 128 to have one, two or more sealing lips, with which the first subgasket sealing area 194a abuts the sealing surface 198 of the first area 196a of the subgasket 192 in a sealing manner.

With the second subgasket sealing area 194b, the sealing element 128 in the assembled state of the electrochemical unit is in sealing contact with a second area 196b of the subgasket 192, which in turn is in sealing contact with the bipolar plate 124' of the electrochemical unit 100' adjacent to the electrochemical unit 100.

In the exemplary embodiment shown in the drawing, provision is made for the second subgasket sealing area 194b to have one, two or more sealing lips 202, with which the second subgasket sealing area 194b rests against the second area 196b of the subgasket 192 in a sealing manner.

As an alternative to this, provision could also be made for the second subgasket sealing area 194b of the sealing element 128 to be designed as a flat seal or a strip seal which, with an essentially flat sealing surface, bears sealingly against the likewise essentially flat sealing surface 204 of the second region 196b of the subgasket 192 .

Furthermore, the sealing element 128 in this embodiment can comprise a bipolar plate sealing area 154, with which the sealing element 126 rests directly on the bipolar plate 124′ of the further electrochemical unit 100′ in a sealing manner.

In the exemplary embodiment illustrated in the drawing, the bipolar plate sealing area 154 has one, two or more sealing lips 156, with which the bipolar plate sealing area 154, when the electrochemical unit 100 is in the assembled state, seals against a preferably substantially planar sealing surface 150' of the additional bipolar plate 124' of the additional electrochemical unit 100'.

When the electrochemical unit 100 is in the assembled state, the first gas diffusion layer 120 can be in contact with the bipolar plate 124 of the electrochemical unit 100 under a contact force.

Provision can also be made for the first gas diffusion layer 120 to be materially bonded to the bipolar plate 124 of the electrochemical unit 100 .

For example, it can be provided that the first gas diffusion layer 120 is injection molded onto the bipolar plate 124 or is glued to the bipolar plate 124 .

Such a materially bonded connection between the first gas diffusion layer 120 and the bipolar plate 124 of the electrochemical unit 100 can also be used with all others described above or below, in particular with those described in FIGS 1 until 15 or 17 until 21 illustrated embodiments of an electrochemical unit 100 for an electrochemical device 106 can be realized.

Incidentally, the in 16 illustrated sixteenth embodiment of an electrochemical unit 100 for an electrochemical device 106 in terms of structure, function and manufacturing method with the in 8th illustrated eighth embodiment match, to the above description reference is made to that extent.

one inside 17 The seventeenth embodiment of an electrochemical unit 100, which is shown in part, differs from that in 16 illustrated sixteenth embodiment in that the electrochemically active composite 158 of the electrochemical unit 100 comprises only the second gas diffusion layer 122, the second electrode 112 and the membrane 114, but not the first electrode 110.

In this embodiment, the first electrode 110 is in the form of a coating applied to the first gas diffusion layer 120 , so that the first gas diffusion layer 120 and the first electrode 110 together form a second electrochemically active composite 168 of the electrochemical unit 100 .

In this embodiment, the subgasket 192 is fixed to the membrane 114 of the first electrochemically active composite 158 of the electrochemical unit 100, for example by gluing and/or by hot pressing.

In order to facilitate this, the outer edge 132 of the first electrode 110 in this embodiment is offset inwardly from the outer edge 130 of the membrane 114 , ie towards the center of the electrochemical unit 100 .

Incidentally, the in 17 illustrated seventeenth embodiment of an electrochemical Technical unit 100 in terms of structure, function and manufacturing method with the in 16 illustrated sixteenth embodiment correspond to the above description reference is made to that extent.

one inside 18 The eighteenth embodiment of an electrochemical unit 100, shown in part, differs from that in 16 illustrated sixteenth embodiment in that the subgasket 192 in the assembled state of the electrochemical unit does not bear directly against the further bipolar plate 124' of a further electrochemical unit 100' adjacent to the electrochemical unit 100, but indirectly via a bipolar plate sealing element 182 which is attached to the further bipolar plate 124' is attached, for example by injection molding.

In addition to sealing element 128, which is connected to bipolar plate 124 of electrochemical unit 100, for example by injection molding, bipolar plate sealing element 182 forms a further component of seal 126 of electrochemical unit 100.

In the exemplary embodiment shown in the drawing, the bipolar plate sealing element 182 has a subgasket sealing area 206, by means of which the bipolar plate sealing element 182 bears sealingly against the second area 196b of the subgasket 192 when the electrochemical unit 100 is in the assembled state.

In the exemplary embodiment illustrated in the drawing, the subgasket sealing area 206 of the bipolar plate sealing element 182 has one, two or more sealing lips 208, with which the subgasket sealing area 206 rests sealingly against a further sealing surface 210 of the second area 196b of the subgasket 192.

As an alternative to this, it could also be provided that the subgasket sealing area 206 of the bipolar plate sealing element 182 is designed as a flat seal or as a strip seal, which has a substantially flat sealing surface on a likewise substantially flat sealing surface 210 of the second region 196b of the subgasket 192 sealing.

Incidentally, the in 18 shown eighteenth embodiment of an electrochemical unit 100 in terms of structure, function and manufacturing method with the in 16 illustrated sixteenth embodiment correspond to the above description reference is made to that extent.

one inside 19 Nineteenth embodiment of an electrochemical unit 100, shown in part, differs from that in 18 illustrated eighteenth embodiment in that the electrochemically active composite 158 comprises only the second gas diffusion layer 122, the second electrode 112 and the membrane 114, but not the first electrode 110.

In this embodiment, the first electrode 110 is in the form of a coating applied to the first gas diffusion layer 120 , so that the first gas diffusion layer 120 and the first electrode 110 together form a second electrochemically active composite 168 of the electrochemical unit 100 .

In this embodiment, the subgasket 192 is fixed to the membrane 114 of the first electrochemically active composite 158, for example by gluing or hot pressing.

To facilitate this, the outer edge 132 of the first electrode 110 is offset inwardly from the outer edge 130 of the membrane 114 , ie towards the center of the electrochemical unit 100 .

Incidentally, the in 19 shown nineteenth embodiment of an electrochemical unit 100 in terms of structure, function and manufacturing method with the in 18 illustrated eighteenth embodiment correspond to the above description reference is made to that extent.

one inside 20 The twentieth embodiment of an electrochemical unit 100, shown in part, differs from that in 18 illustrated eighteenth embodiment in that the seal 126 of the electrochemical unit 100 does not include two sealing elements 128 and 182, which are connected to the bipolar plate 124 of the electrochemical unit 100 or to the further bipolar plate 124' of the electrochemical unit 100 adjacent further electrochemical unit 100' , but instead a sealing element 128, which is connected to the subgasket 192, for example by injection molding.

Provision is preferably made here for the sealing element 128 to be connected to the second region 196b of the subgasket 192 .

The first region 196a of the subgasket 192 is fixed to the electrochemically active composite 158, for example to the first electrode 110. This fixing can be done, for example, by gluing or hot pressing.

The sealing element 128 comprises a bipolar plate sealing region 148 with which the sealing element 128 rests sealingly on the bipolar plate 124 of the electrochemical unit 100 when the electrochemical unit 100 is in the assembled state.

In principle, it can be provided that the bipolar plate sealing area 148 bears with a substantially flat sealing surface against a likewise substantially flat sealing surface 150 of the bipolar plate 124 of the electrochemical unit 100 .

However, the bipolar plate sealing area 148 preferably has one, two or more sealing lips 152 with which the bipolar plate sealing area 158 bears sealingly against the bipolar plate 124 of the electrochemical unit 100 when the electrochemical unit 100 is in the assembled state.

Furthermore, the sealing element 128 comprises a further bipolar plate sealing region 154, which faces away from the bipolar plate 124 of the electrochemical unit 100 when the electrochemical unit 100 is in the assembled state, with which the sealing element 128 in the assembled state of the electrochemical unit 100 on the bipolar plate 124' of one of the electrochemical unit 100 adjacent further electrochemical unit 100 'of the electrochemical device 106 rests sealingly.

In principle, it can be provided that the additional bipolar plate sealing area 154 of the sealing element 128 has an essentially flat sealing surface, with which the additional bipolar plate sealing area 154 in the assembled state of the electrochemical unit 100 can be connected to an also essentially flat sealing surface 150 ′ of the bipolar plate 124 ′. the adjacent electrochemical unit 100' sealingly abuts.

However, the further bipolar plate sealing area 154 preferably has one, two or more sealing lips 156, with which the further bipolar plate sealing area 154 in the assembled state of the electrochemical unit 100 rests sealingly on the bipolar plate 124′ of the adjacent electrochemical unit 100′.

During the assembly of the electrochemical device 106, a first gas diffusion layer 120, an electrochemically active composite 158 and a unit of the subgasket 192 and the sealing element 128 are arranged relative to one another for each electrochemical unit 100 as shown in FIG 20 can be seen, and this sequence of elements is repeated for the further electrochemical units 100' until a stack of the desired number of electrochemical units is formed.

The first gas diffusion layer 120 can be laminated onto the electrochemically active composite 158 prior to assembly.

Incidentally, the in 20 illustrated twentieth embodiment of an electrochemical unit 100 in terms of structure, function and manufacturing method with the in 18 illustrated eighteenth embodiment correspond to the above description reference is made to that extent.

one inside 21 The twenty-first embodiment of an electrochemical unit 100, which is shown in part, differs from that in 20 illustrated twentieth embodiment in that the electrochemically active composite 158 comprises only the second gas diffusion layer 122, the second electrode 112 and the membrane 114, but not the first electrode 110.

In this embodiment, the first electrode 110 is in the form of a coating applied to the first gas diffusion layer 120 , so that the first gas diffusion layer 120 and the first electrode 110 together form a second electrochemically active composite 168 .

In this embodiment, the subgasket 192 is connected to the membrane 114 of the first electrochemically active composite 158, for example by gluing or hot pressing.

To facilitate this, the outer edge 132 of the first electrode 110 is offset inwardly from the outer edge 130 of the membrane 114 , ie towards the center of the electrochemical unit 100 .

The second electrochemically active composite 168 can be laminated to the first electrochemically active composite 158 .

Incidentally, the in 21 illustrated twenty-first embodiment of an electrochemical unit 100 in terms of structure, function and manufacturing method with the in 20 illustrated twentieth embodiment correspond to the above description reference is made to that extent.

Claims (16)

An electrochemical unit for an electrochemical device (106) comprising a membrane (114), a first electrode (110), a second electrode (112), a first gas diffusion layer (120), a second gas diffusion layer (122), a bipolar plate (124) and a gasket (126), which comprises at least one gasket element (128) which is attached to the membrane (114), to the first electrode (110), to the second electrode (112), to a subgasket (192) and/or to the bipolar plate (124) of the electrochemical unit (100) and/or is connected to a bipolar plate (124') of a further electrochemical unit (100') adjacent to the electrochemical unit (100), characterized in that the second electrode (112) and the second gas diffusion layer (122) form an electrochemically active composite ( 158), in which the second electrode (112) is formed as a coating applied to the second gas diffusion layer (122). Electrochemical unit after claim 1 , characterized in that an outer edge (136) of the first gas diffusion layer (120) is offset inwards at least in sections relative to an outer edge (138) of the second gas diffusion layer (122) or the outer edge (138) of the second gas diffusion layer (122) at least is offset inwards in sections relative to an outer edge (136) of the first gas diffusion layer (120). Electrochemical unit according to one of Claims 1 or 2 , characterized in that the seal (126) comprises a first sealing element (160) which is connected to the first gas diffusion layer (120) and/or a second sealing element (162) which is connected to the second gas diffusion layer (122). . Electrochemical unit after claim 3 , characterized in that the respective sealing element (160, 162) comprises a connection area (140) which extends into the first gas diffusion layer (120) or into the second gas diffusion layer (122). Electrochemical unit according to one of Claims 1 until 4 , characterized in that at least one sealing element (128) of the seal (126) comprises a bipolar plate sealing area (148; 154), with which the sealing element (128) in the assembled state of the electrochemical unit (100) on the bipolar plate (124) of electrochemical unit (100) or on a bipolar plate (124 ') of the electrochemical unit (100) adjacent further electrochemical unit (100') rests sealingly. Electrochemical unit after claim 5 , characterized in that the bipolar plate sealing area (148; 154) has one, two or more sealing lips (152; 156). Electrochemical unit according to one of Claims 1 until 6 , characterized in that the seal (126) comprises two sealing elements (160, 162) which are pressed together in the assembled state of the electrochemical unit (100). Electrochemical unit according to one of Claims 1 until 7 , characterized in that at least one sealing element (128) of the seal (126) comprises an electrode sealing area (176) with which the sealing element (128) on the first electrode (110) or on the second electrode (112) of the electrochemical unit (100) and/or that at least one sealing element (128) of the seal (126) comprises a membrane sealing area (170) with which the sealing element (128) forms a seal on the membrane (114) of the electrochemical unit (100). applied. Electrochemical unit according to one of Claims 1 until 8th , characterized in that the seal (126) comprises at least two separate sealing elements (182, 184), of which an inner sealing element (184) is offset inwardly relative to an outer sealing element (182). Electrochemical unit according to one of Claims 1 until 9 , characterized in that the seal (126) comprises at least two sealing elements (128, 186), one sealing element (128) having a groove (188) into which the other sealing element (186) engages. Electrochemical unit according to one of Claims 1 until 10 , characterized in that an outer edge (132) of the first electrode (110) is offset inwards at least in sections relative to an outer edge (134) of the second electrode (112) or an outer edge (134) of the second electrode (112) at least is offset inwards in sections relative to an outer edge (132) of the first electrode (110). Electrochemical unit according to one of Claims 1 until 11 , characterized in that the seal (126) comprises at least one sealing element (128) which is attached to a gas diffusion layer (120; 122) of the electrochemical unit (100) and to the bipolar plate (124) of the electrochemical unit (100) and/or to a bipolar plate (124') of a further electrochemical unit (100') adjacent to the electrochemical unit (100). Electrochemical unit according to one of Claims 1 until 12 , characterized in that the seal (126) comprises at least one sealing element (128) which is attached to a gas diffusion layer (120; 122) of the electrochemical unit (100), to an electrode (110; 112) of the electrochemical unit and/or to the Bipolar plate (124) of the electrochemical unit (100) and/or to a bipolar plate (124') of a further electrochemical unit (100') adjacent to the electrochemical unit (100). Electrochemical unit according to one of Claims 1 until 13 , characterized in that the first electrode (110) and the first gas diffusion layer (120) form an electrochemically active composite (168) in which the first electrode (110) is formed as a coating applied to the first gas diffusion layer (120). Electrochemical unit according to one of Claims 1 until 14 , characterized in that at least one sealing element (128) of the seal (126) comprises at least one subgasket sealing area (194a, 194b), with which the sealing element (128) in the assembled state of the electrochemical unit (100) on a subgasket (192) the electrochemical unit (100) rests sealingly. A method of making an electrochemical unit (100) for an electrochemical device (106), comprising: - Connecting at least one sealing element (128) of a seal (126) of the electrochemical unit (100) to a membrane (114), to a first electrode (110), to a second electrode (112), to a subgasket (192) and/ or to a bipolar plate (124) of the electrochemical unit (100) and/or to a bipolar plate (124') of a further electrochemical unit (100') adjacent to the electrochemical unit (100); - Generating at least one electrochemically active composite (158; 168) by applying at least one electrode (110; 112) as a coating on at least one gas diffusion layer (120; 122) of the electrochemical unit (100); - Assembling the at least one electrochemically active composite (158; 168) and the at least one sealing element (128).

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