Electrochemical cell of stack assembly of PEM electrolysis device or AEM electrolysis device or PEM fuel cell

Abstract

The invention relates to an electrochemical cell (10) of a stack assembly (52) of a PEM electrolysis device or an AEM electrolysis device or a PEM fuel cell, having a plurality of electrochemical cells (10), the electrochemical cells have porous transport structures (20, 22) on the cathode side (24) and the anode side (26) on both sides of the coated membrane (14) and are sealed on both sides within the stack assembly (52) by seals (28, 30). A gap (34) generated between the seal (28, 30) and the porous transport structure (20, 22) on both sides of the coated membrane (14) is filled by a deformable sealing element (46) arranged on the seal (28, 30), in particular a sealing nose wing or a sealing lip, at least in part. The invention further relates to the use of the electrochemical cell (10) in a stack assembly (52) of a PEM electrolysis device or a PEM fuel cell.

Description

Technical Field

[0001] The present invention relates to an electrochemical cell for a stack of a PEM electrolyzer, an AEM electrolyzer, or a PEM fuel cell, comprising a plurality of electrochemical cells. The electrochemical cell comprises porous transmission structures on both sides of a coated membrane, on the cathode side and the anode side, and is sealed on both sides within the stack via seals. The present invention also relates to a method for producing a deformable, circumferential seal for an electrochemical cell, which is configured as a sealing band, and to the use of an electrochemical cell in a stack of a PEM electrolyzer, an AEM electrolyzer, or a PEM fuel cell. Background Art

[0002] WO 18 / 196947 A1 relates to a method for operating a water electrolysis device. In this electrolysis device, water from a PEM electrolysis device is conveyed in a water circuit to a first heat exchanger for cooling, then to an ion exchanger, then to a second heat exchanger for heating, and then to the PEM electrolysis device again. The heat exchanger forms a secondary-side component of a common heat transfer circuit, which has a cooling device through which a heat transfer flow for controlling and / or regulating the temperature of the water conveyed to the ion exchanger and / or the PEM electrolysis device partially or completely passes.

[0003] PEM electrolyzers, AEM electrolyzers, and PEM fuel cells consist of stacked flat elements, just like heat exchangers. Here, the flat elements form the anode-side chamber and cathode-side chamber with the selective separation membrane. The membrane should be similar to that of a PEM fuel cell; in a PEM electrolyzer, only cations, i.e., usually H, are permitted. + The ions pass through to the cathode. The alkaline AEM electrolysis device is fed to the anode and / or cathode by an alkaline solution such as KOH. - In the case of alkaline AEM electrolysis, only anions, that is, OH - The ions pass through in the direction of the anode. For the sake of simplicity, a PEM electrolysis device will be explained below by way of example. When constructing a PEM electrolysis device, water is input into the anode-side chamber and water and oxygen are discharged. The chamber constructed on the cathode side preferably contains mostly the hydrogen formed. Preferably, the hydrogen chamber has a higher pressure on the cathode side, for example on the order of 30 bar, which is greater than the pressure acting in the anode-side chamber, on the order of 1 bar to 5 bar. The aforementioned chambers must be sealed from each other in the stack. Here, the sealing can be carried out by a sealing plate or a sealant applied to a flat surface or by a sealing tape in the form of an O-ring.

[0004] The seal of planar structure requires relatively high pressing force and high material usage. Because in electrolytic cells or fuel cells, the active area is conventionally formed by a flow field (flow field) and conventionally by a porous structure, what is pursued is to connect the seal to the flow field without gaps to prevent reactants or products from flowing around the flow field through the gaps rather than passing through the flow field. Especially at the interface or at the joint area, for example, a seal without gaps on the flow field is not always possible. Here, the diaphragm is pressed into the gap between the mutually opposed seals and the opposing flow field by the pressure difference described above. If, for example, an O-ring is used for sealing, the O-ring is conventionally constructed as a circle in terms of processing technology, that is, the O-ring has a circular cross-section and a circular main dimension. Therefore, the main dimension of the band diameter is obtained, which must be matched with a relatively large mold in the injection molding process. In addition, even if the area inside the large sealing ring is filled with many small sealing rings to make the best use of the die, a large machine with relatively high processing costs is required. Summary of the Invention

[0005] An electrochemical cell for a stack assembly of a PEM electrolyzer, an AEM electrolyzer, or a PEM fuel cell is provided. The electrochemical cell comprises a plurality of electrochemical cells, each of which has a porous transport structure on both sides of a coated membrane, on the cathode side and the anode side, and is sealed on both sides within the stack assembly via a seal. The gaps between the seal and the porous transport structure, which are generated on both sides of the coated membrane, are at least partially filled by deformable sealing elements, in particular sealing wings or lips, provided on the seal.

[0006] By means of the configuration of the seal proposed according to the invention, the pressure conditions within the stack assembly can be used in an advantageous manner to deform a sealing element cast or constructed on the seal due to the existing pressure distribution in such a way that the sealing element rests sealingly against the diaphragm and avoids inadmissible deflections, i.e. inadmissible deformations of the diaphragm due to pressure gradients.

[0007] In an advantageous embodiment of the electrochemical cell proposed according to the invention, the seal is embodied as a flat seal or a sealing strip.

[0008] In an advantageous further development of the electrochemical cell proposed according to the invention, the seal can be provided with a lining that reinforces the seal. This significantly increases the component stability, in particular the dimensional stability of the stack assembly of a PEM electrolyzer or PEM fuel cell, which is subsequently formed by stacking a plurality of electrochemical cells.

[0009] In an advantageous further development of the electrochemical cell proposed according to the invention, the seal is designed to surround the porous transport structure. This type of design of the seal allows for the greatest possible sealing safety.

[0010] In an advantageous embodiment of the electrochemical cell proposed according to the invention, the seal comprises deformable sealing elements facing the porous transport structure, which sealing elements are designed in particular as sealing lips or as sealing wings.

[0011] In an advantageous further development of the electrochemical cell proposed according to the invention, the sealing element facing the porous transport structure can be deformed so that, due to the pressure distribution on the anode side and / or cathode side, the sealing element enters the gap to be sealed and comes to bear against the upper side and / or lower side of the membrane. Thus, by utilizing the pressure distribution prevailing in the electrochemical cell, an advantageous sealing of the porous transport structure against the escape of the medium can be achieved without requiring further sealing measures.

[0012] In an advantageous further development of the electrochemical cell, the region of the seal and / or of the porous transport structure adjoining the upper side and / or the lower side of the membrane is designed with rounded corners or an oval geometry.

[0013] Advantageously, the electrochemical cell is configured such that the porous transport structure is provided with an edge notch which forms a contact surface with an adjacent edge notch of the seal. Alternatively, it can be provided that an edge notch with one or also two rounded corners forms the contact surface for the coated membrane.

[0014] The geometry of such a contact surface can be designed, for example, so that the height of the edge notch is at most 50% of the membrane thickness, and the width of the edge notch can be 1 to 10 times the height of the edge notch. A contact surface configured in this way effectively avoids or limits deformations within the stack that could cause mechanically severe stresses on the membrane due to existing pressure gradients.

[0015] The electrochemical cell proposed according to the invention is designed such that the thickness of the porous transport structure is between 50 μm and 5000 μm, preferably between 200 μm and 2000 μm, and particularly preferably between 300 and 500 μm. This allows for the possibility of selecting a smaller thickness when the porous transport structure comprises an expanded metal grid.

[0016] In the electrochemical cell proposed according to the invention, the seal embodied as a sealing strip has a flat side facing the membrane.

[0017] Advantageously, the flat side of the seal designed as a sealing strip is created such that at least one end, preferably both ends, of the flat side is provided with a sealing element, which can be designed, for example, in the form of a nose.

[0018] In the electrochemical cell proposed according to the invention, when the edge recess is designed as an elliptical geometry, the elliptical geometry is created such that the surface on the major semi-axis of the elliptical geometry faces the seal and the surface on the minor semi-axis of the elliptical geometry faces the membrane.

[0019] Furthermore, the present invention also relates to a method for producing a deformable, circumferential seal of an electrochemical cell, which is designed as a sealing strip, comprising the following method steps:

[0020] a) introducing a serpentine depression into the mold,

[0021] b) applying a flat cover onto the meandering depression in the mold, which is filled with molding compound, for forming the flat side and the sealing element adjoining the flat side, and

[0022] c) The sealing strip with the flat side and the sealing element adjoining the flat side is removed from the mold.

[0023] Furthermore, the present invention relates to the use of an electrochemical cell in a stack assembly of a PEM electrolyser or a PEM fuel cell.

[0024] Advantages of the invention

[0025] The solution proposed according to the invention makes it possible to utilize the pressure distribution around the electrochemical cells accommodated in the stack so that a preferably circumferentially embodied deformable sealing element rests sealingly against, for example, a coated membrane where the flow field is located. This makes it possible to avoid further, particularly circumferentially embodied, sealing elements.

[0026] Advantageously, the sealing element is cast or injection molded directly onto the sealing strip or flat seal during the manufacturing process and is preferably made of a deformable plastic material. Due to the pressure distribution around the electrochemical cell, not only the cathode side with a higher pressure level, but also the anode side, which generally has a lower pressure level, can be effectively sealed from each other. In particular, the solution proposed according to the invention makes it possible to at least reduce, if not completely fill, gaps generated during the construction of the electrochemical cell due to manufacturing errors by the seal. Thus, deformations of the coated diaphragm that are not allowed and could lead to rupture in extreme cases are eliminated. The solution proposed according to the invention makes it possible, in particular, to create a contact surface bounded by a circular or elliptical seal that avoids bending of the sensitive coated diaphragm.

[0027] For example, the solution proposed according to the invention makes it possible to produce a contact surface which is formed on the one hand by edge notches of the porous transport structure and on the other hand by corresponding edge notches on a seal which surrounds the porous transport structure. The edge notches are in particular designed to be burr-free. In addition to the contact surface formed by edge notches, rounded corners or oval geometries can also be designed. The individual edge notches are dimensioned in such a way that they are in the order of magnitude of the typical deformation values ​​of the coated membrane. The height of the edge notches is at most 50% of the thickness of the coated membrane, while the width of the edge notches can be between 1 and 10 times the height of the edge notches in order to achieve effective support for the coated membrane. Typically, the thickness of the porous transport structure has values ​​between 50 μm and 5000 μm, in particular between 300 μm and 500 μm.

[0028] The solution proposed according to the invention utilizes the pressure conditions on the anode or cathode side of the electrochemical cell to prevent leakage of process gas or process fluid H2O, H2 or O2 into the gap under relatively high pressure conditions; in particular, creeping or expansion of the coated diaphragm, particularly into gaps with sharp-edged structures, can be prevented. The coated diaphragm expands by absorbing moisture, and this expansion behavior can depend on the contact pressure. Because the counterpressure in the gap or free space is lower, the diaphragm expands excessively here, so that the solution proposed according to the invention can effectively compensate for diaphragm weakening. This preventive measure prevents the porous transport structure from coming into contact with sharp-edged edges. In addition, mechanical loads generated during operation due to the pressure gradients existing on both sides of the coated diaphragm and cracks in the coated diaphragm are effectively compensated.

[0029] Due to the prevailing pressure conditions, in particular the pressure difference on the cathode side and the anode side of the electrochemical cell proposed according to the invention, the sealing force depends on the prevailing pressure on the cathode side and the anode side.

[0030] By applying the solution proposed according to the present invention, the tolerances of the components used can be further controlled, and the service life can be extended by improving the support against mechanical loads. Thinner coated membranes can be used because their lower mechanical strength is no longer the sole design criterion due to the reduced deformation. Furthermore, the electrochemical cells in a PEM electrolyzer or PEM fuel cell stack can be operated at higher temperatures or pressures, significantly improving the efficiency of such stacks. In particular, the solution proposed according to the present invention allows individual electrochemical cells within a stack to be sealed according to the present invention on both sides, that is, on the cathode and anode sides. If the pressure conditions between the anode and cathode sides are reversed, it can also be ensured that the coated membrane and the medium flowing through it are securely sealed against leakage within the stack.

[0031] For industrial fast or high-speed stacking, that is, to integrate the porous structure into the battery frame or the surrounding seal, larger tolerances or introduction bevels or high positioning costs are usually required, so these costs can be significantly reduced in the case of implementation according to the invention because the sealing nose rests on the porous structure perpendicularly to the membrane plane during the stacking process.

[0032] Furthermore, a membrane that is coated too thickly in the coating area can be removed within the context of reuse or repair. For example, within the context of a parts replacement, the membrane can be replaced by a new component in the form of a coated membrane, and after reassembly, the electrochemical cell, which has been repaired in this way, can continue to be used in the stack. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Embodiments of the present invention are further explained with reference to the accompanying drawings and the following description.

[0034] The accompanying drawings show:

[0035] Figure 1 : cross section through the electrochemical cell,

[0036] Figure 2 : Illustration of the creep behavior of a coated membrane in a gap-shaped free space,

[0037] Figure 3 :In with Figure 2 Comparison of the coated diaphragm creeping into free space with a reversal of the pressure distribution.

[0038] Figure 4 : Graphical representation of key areas,

[0039] Figure 5 : Illustration of the seals above and below the coated diaphragm in the region of the longitudinal medium passage,

[0040] Figures 6.1-6.3 : the configuration of a circumferential sealing element on a seal configured as a flattened seal above the coated diaphragm,

[0041] Figure 7 : Illustration of the sealing elements on the seals on both sides of the coated diaphragm,

[0042] Figure 8 : Schematic diagram of the stack assembly of a PEM electrolyzer,

[0043] Figure 8.1 and 8.2 : Different geometries of the seal and the porous transport structure on both sides of the membrane in the area where they abut one another,

[0044] Figure 9: Illustration of the geometry of a seal configured as a sealing strip,

[0045] Figure 10 : The seal is manufactured in a mold,

[0046] Figure 11 : A top view of an exemplary mold having a meandering recess for accommodating the molding compound forming the sealing strip.

[0047] Figure 1 An electrochemical cell 10 is shown, which is a single cell 12 and includes a coated membrane 14. The membrane 14 comprises an upper side 16 and a lower side 18, and is provided with porous transport structures 20, 22 on both sides. The cathode side is designated by reference numeral 24, while the anode side is designated by reference numeral 26. The porous transport structures 20, 22 on the cathode side 24 and the anode side 26 are each surrounded by a first, circumferentially configured seal 28 or a second, circumferentially configured seal 30. The seals 28, 30 may be provided with a reinforcing lining 32. Due to manufacturing tolerances, a gap 34 arises between the porous transport structures 20, 22 and the seals 28, 30 surrounding them, which are designed here as flat seals. If the seals 28, 30 are compressed during assembly, the gap 34 closes if the dimensions are correct. However, the triangular portion in the region of the edge notch 54 of the gap 34 remains open.

[0048] Depend on Figure 2 and 3 It can be seen that the coated membrane 14 creeps into the gap 34 between the second seal 30 and the porous transport structure 22 on the anode side due to the pressure level on the pressure side 38. Figure 2 Compared to the reversed stress condition, then - as in Figure 3 As shown in FIG, the coated membrane 14 creeps on its upper side 16 into the gap-shaped free space 34 located above, between the first seal 28 and the porous transport structure 20 on the cathode side 24 of the electrochemical cell 10. Figure 2 and 3 The effects shown in are disadvantageous with regard to the service life of the coated membrane 14 and are therefore to be avoided.

[0049] Depend on Figure 4 It can be seen that gaps or free spaces 34 occur in particular on the underside 18 of the coated membrane 14 below the adjoining region between the first seal 28 and the porous transporting structure 20 and in the boundary region between the second seal 30 and the porous transporting structure 22 .

[0050] Figure 5It is shown that, on the one hand, in the region of the adjoining area between the porous transport structure 20 on the cathode side 24 and the coated membrane 14 in the region of the longitudinal medium channel 42, and on the other hand, in the region of the adjoining area between the second seal 30 and the porous transport structure 22 on the anode side 26, on the bottom side 18 Figure 4 36 of the membrane 14 is shown in FIG. This occurs under the condition of a corresponding pressure distribution between the pressure side 38 and the low-pressure side 40 . DETAILED DESCRIPTION

[0051] In the following description of exemplary embodiments of the present invention, identical or similar elements are identified with the same reference numerals, wherein a repeated description of an element is omitted in individual cases. The figures merely schematically illustrate the subject matter of the present invention.

[0052] Depend on Figure 6.1 、 6.2 6.3, the first seal 28, which is implemented as a flat seal in this embodiment variant, also includes a sealing element 46 in addition to the reinforcing lining 32. Figure 6.1 The sealing element 46 can be designed as a circumferential sealing lip or as a circumferential sealing wing. Both the first seal 28 and the second seal 30, also designed here as a flat seal, extend around the porous transmission structures 20, 22 located on the upper side 16 or lower side 18 of the coated membrane 14, which has a flow field for the medium. The seals 28, 30 are preferably made of a flexibly deformable, elastic plastic material.

[0053] Depend on Figure 6.2 It can be seen that a pressure distribution 48 is provided in the gap-shaped free space 34 between the porous transmission structure 20 and the first seal 28, which acts on the sealing element 46, whether it is designed as a circumferential nose or as a circumferential lip. The sealing element 46 is therefore attached to the upper side 16 of the coated membrane 14.

[0054] This can be seen in particular in the Figure 6.3 Due to the deformability of the sealing element 46 , the pressure level prevailing on the pressure side 38 , ie, the cathode side 24 of the electrochemical cell 10 , is sufficient to cause the sealing element 46 to rest sealingly 50 against the upper side 16 of the coated diaphragm 14 .

[0055] Depend on Figure 7 It can be seen that in this embodiment variant, the first seal 28, which is designed here as a flat seal, and the second seal 30, which is also designed here as a flat seal and has a reinforcing lining 32, are formed with a surrounding sealing element 46. In the event of a reversal of the pressure conditions, such as in combination with Figure 2 and Figure 3As shown with respect to the coated membrane 14, the Figure 7 The embodiment variant realizes the sealing of the coated membrane 14 on both sides, for the gap-shaped free space 34. In this embodiment variant, the sealing element 46, whether a surrounding sealing nose or a surrounding sealing lip, is made of a deformable elastic plastic material. Figure 6.3 It is shown that the coated membrane 14 can be placed in sealing contact 50 on both sides, ie, on the upper side 16 and on the lower side 18 .

[0056] Figure 8 A stack 52 of electrochemical cells 10 is shown schematically within a PEM electrolysis device. Alternatively, the stack 52 can also be a stack for use in a PEM fuel cell.

[0057] Depend on Figure 8.1 and 8.2 Different geometries of the boundary regions between the first seal 28 and the porous transporting structure 20 on the upper side 16 of the coated membrane 14 and between the second seal 30 and the porous transporting structure 22 on the lower side 18 of the coated membrane 14 are apparent.

[0058] Figure 8.1 It is shown, here in particular on the underside 18 of the coated membrane 14, that the second seal 30 and the porous transport structure 22 below the coated membrane 14 each have an edge notch 54. The two edge notches 54 of the second seal 30 and the porous transport structure 22 on the anode side 26 facing each other form a wedge-shaped support surface 56. However, this support surface is not as deep as the gap 34, as shown in conjunction with Figure 2 and 3 As shown, the deflection of the coated diaphragm 14 can be significantly reduced due to the reduced depth of the support surface 56. As a result, cracking of the coated diaphragm 14 and excessive mechanical stress can be avoided. Figure 8.1 As shown in FIG, at the edge notch 54, a rounded corner 58 can also be realized in the adjacent components of the first seal 28 and the porous transport structure 20 on the upper side 16 of the coated membrane 14 (see FIG. Figure 8.2 ). In addition, there is the possibility that the mutually adjacent regions of the seals 28, 30 and the porous transport structures 20, 22 are also designed with an elliptical geometry 60. Figure 8.2 As can be seen from the schematic diagram of FIG, the elliptical geometry 60 has a major semi-axis 62 and a minor semi-axis 64. The surfaces corresponding to these are configured such that the surface of the major semi-axis 62 of the elliptical profile 60 faces the surface of the first seal 28 and the surface of the minor semi-axis 64 of the elliptical profile 60 faces the surface of the coated diaphragm 14. Figure 8.1The edge notches 54 mentioned are of the order of magnitude of typical deformation values ​​of the coated membrane 14. Therefore, the height 68 of the edge notches 54 is in the region of at most 50% of the thickness 70 of the coated membrane 14, while the width 72 of the edge notches 54 is 1 to 10 times the height 68 of the edge notches 54 to achieve good support. Typically, the height 74 of the porous transport structures 20, 22 is between 50 μm and 5000 μm, in particular between 300 μm and 500 μm.

[0059] Based on Figure 8 As can be seen from the schematic diagram of FIG, on the one hand, the edge notch 54 and on the other hand, the other edge notch 66 form a wedge-shaped support surface 56. Depending on the slope of the edge notches 54, 66, a larger or smaller width 72 of the support surface 56 is obtained.

[0060] By attaching Figure 8.1 and 8.2 The illustrated geometry, namely the gently sloping support surface 56, the elliptical geometry 60, or the rounded corners 58 of the adjacent regions of the components 20, 22, 28, and 30, results in a significantly reduced creep potential, which could cause the coated membrane 14 to deflect during operation of the electrochemical cell 10 due to large pressure differences across the coated membrane 14. The solution proposed according to the present invention effectively limits the deflection of the coated membrane 14 toward the upper side 16 and toward its lower side 18, significantly reducing the mechanical stresses on the coated membrane 14 due to the pressure distribution. Consequently, the service life of the electrochemical cells 10 housed in the stack 52 of a PEM fuel cell or PEM electrolyzer can be significantly extended, and the efficiency of the stack 52 during operation can be significantly improved.

[0061] Based on Figure 9 and 10 As can be seen from the schematic diagram of FIG, the sealing elements 28, 30 can also be processed as sealing strips 86. The seals 28, 30 processed as sealing strips 86 can be created so that the sealing strips have a flat side 82 on their upper side, which is delimited at least at one end by a nose-shaped projection forming the sealing element 46. Figure 9 and attached Figure 10 As can be seen from the schematic diagram of the embodiment of the present invention, the sealing body 80 of the sealing strip 86 has a substantially rectangular cross section. The sealing elements 46 cast on both sides of the flat side 82 fill in the areas where the sealing element 46, designed as a sealing strip 86, adjoins the porous transport structure 22 on the anode side 26, that is, on the bottom side 18, of the coated membrane 14. As shown in the attached figure, Figure 9 As shown in FIG, due to the geometric shape of the sealing members 28, 30 processed into the sealing band 86, according to the attached Figure 2 and attached Figure 3The gaps or free spaces 34 at the porous transport structure 22 extending onto the anode side 26 of the coated membrane 14 are effectively filled so that the coated membrane 14 cannot deform due to the pressure gradient between the pressure side 38 and the low pressure side 40 .

[0062] By the attached Figure 11 In a schematic manner, it is apparent that the mold 88 for producing the seal 28, 30 configured as a sealing strip 86 has a meandering recess 90. Figure 11 In the diagram, the mold 88 is shown schematically in a top view, which is closed by a flat cover, so that when the meandering recess 90 in the mold 88 is filled, a serpentine-shaped recess 90 is formed on the upper side of the sealing body 80. Figure 10 The kind of flat side 82 shown in. Due to the geometry of the recess 90 of the meandering shape in the mold 88, when manufacturing the sealing body 80, the sealing element 46 of the nose-shaped structure described here is manufactured on one side or both sides on the flat side 82.

[0063] In a method for producing a sealing band 86 as a deformable, circumferential seal 28 , 30 of an electrochemical cell 10 , the following method steps are performed:

[0064] a) introducing a meandering recess 90 into the mold 88,

[0065] b) applying the flat cover onto the meandering depression 90 filled with molding compound in the mold 88 for forming the flat side 82 and the sealing element 46 adjoining it and

[0066] c) The sealing strip 86 with the flat side 82 and the sealing element 46 delimiting the flat side is removed from the mold 88 .

[0067] In the attached Figure 11 The mold 88, shown only schematically, is not split centrally, but rather a meandering depression 90 is introduced into one mold side and a flat cover is placed for injection molding. Thus, the aforementioned sealing element 46 is produced on both sides of the flat side 82. The sealing element 46, designed in this case in the shape of a nose, can be used to fill the gap-shaped cavity 34 above or below the coated membrane 14.

[0068] The embodiment variants of the seals 28, 30 proposed according to the invention, which are designed as flat seals or as sealing strips 86, make it possible to achieve effective sealing of the electrochemical cells 10, in particular those accommodated in a stack 52 of a PEM electrolyzer or PEM fuel cell. Leakage of media such as H2O, H2, or O2 can be avoided by the deformation of the sealing element 46 due to the prevailing pressure conditions. This ensures that the medium flows through the flow field of the coated membrane 14 and does not penetrate into other areas.

[0069] As described above, if the supporting surfaces 56 between adjacent components are configured accordingly with rounded corners 58, an oval geometry 60, or a moderate inclination, a strong deflection of the coated membrane 14 due to the pressure distribution between the cathode side 24 and the anode side 26 is eliminated, which significantly improves the service life and operation of the electrochemical cell 10 according to the present invention. In particular, sharp edge-like transitions that could lead to cracks in the coated membrane 14 can be significantly avoided, which is extremely beneficial to the service life of the electrochemical cell 10 according to the present invention.

[0070] The invention is not limited to the embodiments described herein and the aspects highlighted therein. Instead, numerous modifications within the scope of the person skilled in the art are possible within the scope of the claims.

Claims

1. An electrochemical cell (10) for a stack (52) of a PEM electrolyser or AEM electrolyser or PEM fuel cell, comprising a plurality of electrochemical cells (10) which have porous transport structures (20, 22) on both sides of a coated membrane (14) on the cathode side (24) and the anode side (26) and are sealed on both sides within the stack (52) by seals (28, 30), characterized in that The gap (34) generated on both sides of the coated membrane (14) between the seal (28, 30) and the porous transmission structure (20, 22) is at least partially filled by a deformable sealing element (46), in particular a sealing nose or a sealing lip, arranged on the seal (28, 30).

2. The electrochemical cell (10) according to claim 1, characterized in that The seals (28, 30) are designed as flat seals or as sealing strips (86).

3. The electrochemical cell (10) according to claim 1, characterized in that The seals (28, 30) are provided with a liner (32) that reinforces the seals.

4. The electrochemical cell (10) according to claim 1, characterized in that The seal (28, 30) is embodied circumferentially around the porous transport structure (20, 22).

5. The electrochemical cell (10) according to claim 1, characterized in that The seal (28, 30) comprises a deformable sealing element (46), in particular a sealing lip or a sealing nose, facing the porous transmission structure (20, 22).

6. The electrochemical cell (10) according to claim 5, characterized in that The sealing element (46) facing the porous transport structure (20, 22) can be deformed in such a way that it enters the gap (34) to be sealed due to the pressure distribution (48) and comes to bear (50) against the upper side (16) and / or the lower side (18) of the diaphragm (14).

7. The electrochemical cell (10) according to claims 1 to 6, characterized in that The areas of the seal (28, 30) and / or the porous transport structure (20, 22) that bear against the upper side (16) and / or lower side (18) of the membrane (14) are embodied as rounded corners (58) or an elliptical geometry (60).

8. The electrochemical cell (10) according to claims 1 to 7, characterized in that The porous transmission structure (20, 22) is provided with an edge notch (54), which forms a support surface (56) with the edge notch (54) of the adjacent sealing element (28, 30), or an edge notch (54) with one rounded corner (58) or two rounded corners (58) adjacent to each other forms the support surface (56).

9. The electrochemical cell (10) according to claim 8, characterized in that The height of the edge notch (54) is at most 50% of the thickness (70) of the membrane (14).

10. The electrochemical cell (10) according to claim 8, characterized in that The width (72) of the edge notch (34) is 1 to 10 times the height (68) of the edge notch (54).

11. The electrochemical cell (10) according to claims 1 to 10, characterized in that The porous transport structure (20, 22) has a thickness between 50 μm and 2000 μm, in particular between 300 μm and 500 μm.

12. The electrochemical cell (10) according to claim 1 and 2, characterized in that The seal (28, 30) embodied as a sealing strip (86) has a flat side (82) facing the membrane (14).

13. The electrochemical cell (10) according to claim 12, characterized in that The flat side (82) is provided with a sealing element (46) at least on one end.

14. The electrochemical cell (10) according to claim 7, characterized in that The elliptical geometry (60) is designed such that the surface on the semi-major axis (62) of the elliptical geometry (60) faces the seal (28, 30) and the surface on the semi-minor axis (64) of the elliptical geometry (60) faces the diaphragm (14).

15. A method for producing a deformable, circumferential seal (28, 30) for an electrochemical cell (10) in the form of a sealing strip (86), comprising the following method steps: a) introducing a serpentine-shaped depression (90) into the mold (88); b) applying a flat cover onto a meandering depression (90) filled with molding compound in the mold (88) for forming the flat side (82) and the sealing element (46) adjoining the flat side; c) removing the sealing strip (86) having the flat side (82) and the sealing element (46) adjacent to the flat side from the mold (88).

16. Use of the electrochemical cell (10) according to any one of claims 1 to 14 in a stack assembly (52) of a PEM electrolyser or an AEM electrolyser or a PEM fuel cell.

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