Membrane electrode assembly, fuel cell stack, and vehicle having such a fuel cell stack

Abstract

A membrane electrode assembly (14) includes a membrane structure (140) having an anode layer, a cathode layer, and a membrane layer, wherein the membrane layer is located between the anode layer and the cathode layer. The membrane electrode assembly (14) further includes an anode-side gas diffusion layer (1410) arranged on the anode side. The membrane electrode assembly also includes a cathode-side gas diffusion layer (1420) arranged on the cathode side. In addition, at least one of the anode-side gas diffusion layer (1410) and the cathode-side gas diffusion layer (1420) has a structuring (1411, 1421) on a side facing away from the membrane structure. According to the present invention, the structuring includes a plurality of columns (1412, 1422) for constructing a laterally open flow field, wherein the columns (1412, 1422) have contact surfaces (1413, 1423) for placing bipolar plates.

Description

Technical Field

[0001] The present invention relates to a membrane electrode assembly, a fuel cell stack having such a membrane electrode assembly, and a vehicle comprising such a fuel cell stack. Background Art

[0002] Fuel cells generate electrical energy by chemically converting fuel and oxygen into water. To this end, fuel cells contain a so-called membrane electrode assembly (MEA) as a core component. The membrane electrode unit is a structure consisting of an ion-conducting (mostly hydrogen ion-conducting) membrane and catalytic electrodes (anode and cathode) arranged on both sides of the membrane. The latter mostly include supported precious metals, especially platinum. In addition, gas diffusion layers (GDLs) on both sides of the membrane electrode assembly can be arranged on the side of the electrode facing away from the membrane. Fuel cells are usually formed by a plurality of MEAs arranged in a stack, the electrical power of the MEAs being added together. Bipolar plates (also called flow field plates or diaphragm plates) are usually arranged between the individual membrane electrode assemblies. These bipolar plates ensure the supply of working medium, i.e. reactants, to the individual cells and are usually also used for cooling. These bipolar plates also provide conductive contact with the membrane electrode assembly.

[0003] During fuel cell operation, fuel (anode working medium), in particular hydrogen H2 or a hydrogen-containing gas mixture, is supplied to the anode via the flow field of the bipolar plate, which is open on the anode side, where H2 is electrochemically oxidized to hydrogen ions H2 by releasing electrons. + (H2→2H + +2e – ). Hydrogen ions are transported from the anode region to the cathode region (in a water-bound or anhydrous manner) via an electrolyte or a membrane that separates the reaction chambers from each other in a gas-tight and electrically insulating manner. The electrons provided at the anode are directed to the cathode via an electrical wire. Oxygen or an oxygen-containing gas mixture (e.g., air) is supplied to the cathode as a cathode working medium via a flow field of a bipolar plate that is open on the cathode side, so that when electrons are absorbed, O2 is reduced to O 2- (1 / 2O2+2e – →O 2- At the same time, the oxygen ions react in the cathode region with the hydrogen ions transported through the membrane to form water (O 2- +2H + →H2O).

[0004] The fuel cell stack is supplied with its working media, namely, anode fuel gas (e.g., hydrogen), cathode fuel gas (e.g., air), and coolant, via main supply channels that extend throughout the stack and are transported from these channels through the bipolar plates to the individual cells. For each working medium, there are at least two such main supply channels: one for supplying the corresponding working medium and one for discharging the working medium.

[0005] The fuel cell stack is subjected to compressive pressure, typically using hardware springs which add significant weight. Summary of the Invention

[0006] The object of the present invention is now to provide a membrane electrode assembly and a fuel cell stack having such a membrane electrode assembly, which improve the compression properties and the structural design of the fuel cell stack.

[0007] This object is achieved by a membrane electrode assembly according to the invention, a fuel cell stack having such a membrane electrode assembly, and a vehicle having such a fuel cell stack.

[0008] The membrane electrode assembly according to the present invention comprises a membrane structure having an anode layer, a cathode layer and a membrane layer, wherein the membrane layer is located between the anode layer and the cathode layer. The membrane electrode assembly further comprises an anode-side gas diffusion layer arranged on the anode layer. The membrane electrode assembly further comprises a cathode-side gas diffusion layer arranged on the cathode layer. In addition, at least one of the anode-side gas diffusion layer and the cathode-side gas diffusion layer has a structuring on the side facing away from the membrane structure. According to the present invention, the structuring comprises a plurality of columns for constructing a laterally open flow field, wherein the columns have contact surfaces for accommodating bipolar plates. The columns of the gas diffusion layer advantageously achieve a spring action under compression, thereby making it possible, for example, to replace hardware springs. In addition, the columns also reduce induced stresses.

[0009] Preferably, the anode-side gas diffusion layer has a first structure on the side facing away from the membrane structure, while the cathode-side gas diffusion layer has a second structure on the side facing away from the membrane structure. The first structure includes a plurality of first pillars for forming a laterally open flow field, wherein these first pillars have a first contact surface for receiving the bipolar plates. Furthermore, the second structure includes a plurality of second pillars, wherein these second pillars have a second contact surface for receiving the bipolar plates. In this case, a double-sided pillar structure is obtained, thereby further improving or enhancing the spring action and further reducing induced stress.

[0010] Preferably, the first and second columns are positioned so that for every first column, there is a second column positioned opposite the membrane structure. In this case, a two-sided column structure is obtained, wherein the columns form a linear arrangement. This further enhances the compression properties and the spring action.

[0011] The first pillar may have a first height, and the second pillar may have a second height, wherein the first height and / or the second height is 250-450 μm, more preferably 300-400 μm, and particularly preferably 350 μm. These heights are particularly suitable for achieving a particularly robust design. In particular, the thickness provides stiffness for achieving a rebound effect.

[0012] Another aspect of the present invention relates to a fuel cell stack comprising bipolar plates arranged alternately between two end plates and a stack of membrane electrode assemblies according to the present invention. Due to the columnar structure of the membrane electrode assemblies, this fuel cell stack has improved structural integrity. Additional hardware springs can be eliminated, thereby significantly reducing the weight of the fuel cell stack.

[0013] Preferably, the bipolar plate comprises an anode plate, the anode side of which faces the anode-side gas diffusion layer of the membrane electrode assembly; and a cathode plate, the cathode side of which faces the cathode-side gas diffusion layer of the membrane electrode assembly, wherein the anode side of the anode plate and / or the cathode side of the cathode plate are flat. Thus, the bipolar plate is structured on one side, which reduces production costs and ensures that the bipolar plate remains securely flat.

[0014] Advantageously, at least one of the coolant sides of the anode plate or the cathode plate includes a third structure for creating a laterally open coolant flow field. This third structure includes a plurality of third columns, which, along with the first and second columns, are positioned overlapping in the stacking direction. In other words, all columns are stacked one on top of the other. This columnar structure further improves the spring action and enhances the structural robustness of the bipolar plate.

[0015] Preferably, either the anode plate or the cathode plate is designed to be flat on both sides. Due to the simplicity of the bipolar plate, costs and production expenses can be reduced. In addition, the bipolar plate can be designed to be particularly stable.

[0016] Another aspect of the present invention relates to a fuel cell system having a fuel cell stack according to the present invention. In particular, the fuel cell system comprises, in addition to the fuel cell stack, an anode supply device and a cathode supply device, which have corresponding peripheral components.

[0017] Another aspect of the invention relates to a vehicle having a fuel cell stack according to the invention. The vehicle is preferably an electric vehicle, wherein the electrical energy generated by the fuel cell system is used to supply a traction motor and / or a traction battery.

[0018] Further preferred embodiments of the invention result from the remaining features mentioned below.

[0019] Unless otherwise indicated in individual cases, the different embodiments of the invention mentioned in this application can be advantageously combined with one another. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will now be described in detail with reference to the accompanying drawings, in which:

[0021] Figure 1 A block diagram of a fuel cell system according to a preferred design is shown;

[0022] Figure 2 The membrane electrode assembly according to the invention is shown in an oblique view according to a preferred embodiment;

[0023] Figure 3 A section of a fuel cell stack according to the invention according to a preferred embodiment is shown in a transverse view. DETAILED DESCRIPTION

[0024] Figure 1 A fuel cell system according to a preferred embodiment of the present invention is shown, generally designated 100. Fuel cell system 100 is part of a vehicle (not shown in detail), in particular an electric vehicle, which has a traction motor supplied with electrical energy via fuel cell system 100.

[0025] Fuel cell system 100 has a fuel cell stack 10 as its core component. The stack comprises a plurality of individual cells 11 arranged in a stack. These cells are constructed by alternatingly stacking membrane electrode assemblies (MEAs) 14 and bipolar plates 15 (see detailed excerpt). Each individual cell 11 includes an MEA 14, which comprises a membrane layer, preferably an ion-conducting polymer electrolyte membrane, and catalytic electrodes arranged on either side of the membrane layer, namely an anode layer and a cathode layer. The catalytic electrodes catalyze the corresponding sub-reactions of the fuel cell conversion and are typically configured as coatings on the membrane layer. Both the anode and cathode electrodes include a catalytic material, such as platinum, supported on a conductive support material (e.g., a carbon-based material) with a large specific surface area. Thus, an anode region 12 is formed between a bipolar plate 15 and the anode, and a cathode region 13 is formed between the cathode and the next bipolar plate 15. The bipolar plates 15 also provide electrical connections between the individual fuel cells. The bipolar plates also have an internal coolant channel system, which serves to convey the coolant and thus to control the temperature of the stack 10 . The membrane electrode assembly 14 further comprises gas diffusion layers 1410 , 1420 , which face the bipolar plates 15 .

[0026] In order to supply the fuel cell stack 10 with the working medium, the fuel cell system 100 has, on the one hand, an anode supply device 20 and, on the other hand, a cathode supply device 30 .

[0027] The anode supply system 20 includes an anode supply path 21 for delivering an anode operating medium (fuel), such as hydrogen, to the anode region 12 of the fuel cell stack 10. For this purpose, the anode supply path 21 connects a fuel reservoir 23 to the anode inlet of the fuel cell stack 10. The anode supply system 20 also includes an anode exhaust gas path 22, which discharges anode exhaust gas from the anode region 12 through the anode outlet of the fuel cell stack 10. The anode operating pressure on the anode side of the fuel cell stack 10 can be regulated by a regulating device 24 in the anode supply path 21. Furthermore, the anode supply system 20 may include a fuel recirculation line 25, as shown, connecting the anode exhaust gas path 22 to the anode supply path 21. A delivery device 26, such as a motor-driven compressor, is arranged in the fuel recirculation line 25 to deliver the anode exhaust gas. Recirculation of fuel is common so that most of the fuel used in excess of stoichiometric quantities can be returned to the stack for use.

[0028] The cathode supply system 30 includes a cathode supply path 31, which delivers an oxygen-containing cathode working medium, particularly air, to the cathode region 13 of the fuel cell stack 10. This oxygen-containing cathode working medium is drawn in from the surrounding environment. The cathode supply system 30 also includes a cathode exhaust gas path 32, which discharges cathode exhaust gas (particularly exhaust gas) from the cathode region 13 of the fuel cell stack 10 and, if necessary, delivers this cathode exhaust gas to an exhaust system (not shown). A compressor 33 is arranged in the cathode supply path 31 to deliver and compress the cathode working medium. In the illustrated embodiment, the compressor 33 is designed as a primarily electromechanical compressor, driven by an electric motor 34 equipped with corresponding power electronics 35. The compressor 33 can also be driven auxiliary by a turbine 36 (possibly with variable turbine geometry) arranged in the cathode exhaust gas path 32 via a common shaft.

[0029] According to the illustrated embodiment, the cathode supply system 30 may also include an exhaust valve line 37, which connects the cathode supply path 31 to the cathode exhaust path 32. This exhaust valve line bypasses the fuel cell stack 10. The exhaust valve line 37 allows excess air mass flow to pass through the fuel cell stack 10 without shutting down the compressor 33. A regulating device 38 arranged in the exhaust valve line 37 is used to control the amount of cathode operating medium that bypasses the fuel cell stack 10. All regulating devices 24, 38 of the fuel cell system 100 can be designed as adjustable or non-adjustable valves or valves. Corresponding additional regulating devices can be arranged in these lines to isolate the fuel cell stack 10 from the surrounding environment.

[0030] The fuel cell system 100 may also have a humidifier 39. On the one hand, the humidifier 39 is arranged in the cathode supply path 31 so that the cathode gas fuel can flow through the humidifier. On the other hand, the humidifier is arranged in the cathode exhaust gas path 32 so that the cathode exhaust gas can flow through the humidifier. The humidifier 39 usually has a plurality of water vapor permeable membranes, which are constructed flat or in the form of hollow fibers. Here, relatively dry cathode gas fuel (air) flows out from one side of these membranes and relatively moist cathode exhaust gas (exhaust gas) flows out from the other side. Driven by the higher partial pressure on the water vapor in the cathode exhaust gas, water vapor is transferred through the membrane into the cathode gas fuel, which is moistened in this way.

[0031] Other different details of the anode supply device 20 and the cathode supply device 30 are simplified in FIG. Figure 1For reasons of clarity, this is not shown. Thus, a dehydrator can be built into the anode exhaust gas path 22 and / or the cathode exhaust gas path 32 to liquefy and discharge the product water formed from the fuel cell reaction. Finally, the anode exhaust gas path 22 can open into the cathode exhaust gas path 32, allowing the anode exhaust gas and cathode exhaust gas to be discharged through a common exhaust system.

[0032] exist Figure 2 , a membrane electrode assembly 14 according to the present invention is shown according to a preferred embodiment. Here, membrane electrode assembly 14 comprises a membrane structure 140 having an anode layer, a cathode layer, and a membrane layer, wherein the membrane layer is located between the anode layer and the cathode layer. Furthermore, an anode-side gas diffusion layer 1410 is arranged on the anode layer. Furthermore, a cathode-side gas diffusion layer 1420 is arranged on the cathode layer.

[0033] In this embodiment variant, the anode-side gas diffusion layer 1410 has a first structuring 1411 on the side facing away from the membrane structure 140. The first structuring 1411 of the anode-side gas diffusion layer 1410 includes a plurality of first pillars 1412 for forming a laterally open flow field. Preferably, this flow field is designed for transporting an anode gas fuel, such as oxygen, air, or another suitable anode gas fuel. These first pillars 1412 form first contact surfaces 1413, which are used to accommodate the bipolar plates 15. Furthermore, in this embodiment variant, the cathode-side gas diffusion layer 1420 has a second structuring 1421 on the side facing away from the membrane structure 140. This second structuring also includes a plurality of second pillars 1422 in this embodiment for forming a laterally open flow field. These second pillars, in turn, form second contact surfaces 1423 for accommodating the bipolar plates. Preferably, this flow field is designed for transporting a cathode gas fuel, such as hydrogen.

[0034] However, the present invention is not limited to structuring both anode-side gas diffusion layer 1410 and cathode-side gas diffusion layer 1420. In other embodiments of membrane electrode assembly 14, only anode-side gas diffusion layer 1410 has first structuring 1411 with first pillars 1412 for forming a laterally open flow field, while cathode-side gas diffusion layer 1420 is, for example, flat. In another embodiment of membrane electrode assembly 14, only cathode-side gas diffusion layer 1420 has second structuring 1421 with second pillars 1422 for forming a laterally open flow field, while anode-side gas diffusion layer 1410 is, for example, flat. Thus, at least one of gas diffusion layers 1410 and 1420 is always constructed with structuring 1411 and 1421 provided with pillars 1412 and 1422.

[0035] The advantage obtained by the columnar protrusions is that they behave like springs under compression. In this way, the induced stresses are also reduced to a minimum. External hardware springs can then be omitted when used in a fuel cell stack, which advantageously leads to a significant weight reduction. Preferably, carbon-based materials are used as the material for the gas diffusion layers 1410, 1420 and their columns 1412, 1422. For example, the gas diffusion layer can be composed of a double-layer carbon-based porous material, which includes a macroporous support material (carbon fiber paper or carbon cloth) and a thin microporous carbon base layer. In such an embodiment, the support material determines the mechanical properties under compression, bending or shear. Different forms and configurations of carbon can also be used, such as carbon nanostructures, graphite or graphene foam, carbon nanotubes or carbon nanofibers.

[0036] In this exemplary embodiment, first pillars 1412 and second pillars 1422 are positioned such that for each first pillar 1412, there is a second pillar 1422 opposed with respect to membrane structure 140. In this embodiment, an enhanced spring action of the opposed pillars 1412, 1422 is obtained under compression, thereby replacing the hardware springs of fuel cell stack 10.

[0037] Furthermore, in this preferred embodiment, the first height 1414 of the first pillar 1412 and the second height 1424 of the second pillar 1422 are the same. In other embodiments, the first pillar 1412 may be different from the second pillar 1422. Purely by way of example, the first pillar 1412 and the second pillar 1422 have square cross-sections. However, the present invention is not limited to a particular cross-sectional shape, and rectangular or circular cross-sections or other suitable cross-sections are also contemplated.

[0038] In the present embodiment, the columns 1412, 1422 exemplarily form a grid composed of knob-shaped or island-shaped columns 1412, 1422. This accordingly creates a laterally open flow field. In other words, in this case, the columns 1412, 1422 are simply a grid composed of isolated columns, thereby also forming a connected flow field extending in two dimensions.

[0039] Advantageously, the first height 1414 of the first pillars 1412 of the anode-side gas diffusion layer 1410 has a value of 350 μm, which, purely by way of example, corresponds to the value of the second height 1424 of the second pillars 1422. The anode-side gas diffusion layer 1410 also has a flat first base 1415, relative to which the first height 1414 of the first pillars 1412 is measured. Purely by way of example, the first base height 1416 of the first base has a value of 185 μm, although the present invention is not limited to this value. In this embodiment variant, the cathode-side gas diffusion layer 1420 also has a flat second base 1425, relative to which the second height 1424 of the second pillars 1422 is measured. The second base height 1426 of the second base 1425 also has a value of 185 μm, by way of example.

[0040] exist Figure 3 , a fuel cell stack 10 or a portion of such a fuel cell stack 10 according to a preferred embodiment is also shown in a side view. The fuel cell stack 10 comprises a membrane electrode assembly 14 according to the invention, which is inserted between two bipolar plates 15. The stack of alternating bipolar plates 15 and membrane electrode assemblies 14 of the fuel cell stack 10 extends along a stacking direction S.

[0041] Here, the membrane electrode assembly 14 located between these bipolar plates 15 corresponds to Figure 2 For further description of the membrane electrode assembly 14 and other embodiments, see Figure 2 and the accompanying instruction manual.

[0042] The bipolar plate 15 used in the fuel cell stack 10 is described further below. Here, the bipolar plate 15 includes an anode plate 1510, whose anode side 1511 faces or rests against the anode-side gas diffusion layer 1410 of the membrane electrode assembly 14. The bipolar plate 15 also includes a cathode plate 1520, whose cathode side 1521 faces the cathode-side gas diffusion layer 1420 of the membrane electrode assembly 14.

[0043] In the present embodiment, the anode side 1511 of the anode plate 1510 is designed to be flat. In other words, the anode side 1511 is designed to be unstructured. Due to the flatness of the anode side 1511, the flow field formed by the first structuring 1411 of the anode-side gas diffusion layer 1410 is covered or closed in the stacking direction S.

[0044] Furthermore, in the present embodiment, the cathode side 1521 of the cathode plate 1520 is also flat. In other words, the cathode side 1521 is structureless. Because the cathode side 1521 is flat, the flow field formed by the second structuring 1421 of the cathode-side gas diffusion layer 1420 is covered or closed in the stacking direction S. Consequently, the bipolar plate 15 does not need to have structures for the gaseous fuel, as these structures are already present in the membrane electrode assembly 14. This allows for a simpler design of the bipolar plate 15.

[0045] In other embodiments in which only cathode-side gas diffusion layer 1420 of membrane electrode assembly 14 is structured, only cathode side 1521 of cathode plate 1520 is flat. In other embodiments in which only anode-side gas diffusion layer 1410 is structured, only anode side 1511 of anode plate 1510 is flat.

[0046] In this embodiment, the bipolar plates 15 also form an internal coolant flow field. To this end, the coolant side 1522 of the cathode plate 1520 exemplarily has a third structuring 1523. Here, the third structuring 1523 includes corresponding third columns 1524 for forming a laterally open coolant flow field. These third columns, in turn, have third contact surfaces 1525 for receiving the anode plate 1510. In this preferred embodiment, the anode plate 1510 is flat on both sides, so that the coolant side of the anode plate 1510 closes or covers the coolant flow field in the stacking direction S.

[0047] In this case, these simply structured bipolar plates 15 are particularly stable.

[0048] Third columns 1524 are also positioned so that they overlap with first columns 1412 and second columns 1422 of membrane electrode assembly 14 along stacking direction S. In other words, first, second, and third columns 1412 , 1422 , 1524 form a linear arrangement along stacking direction S.

[0049] When the described fuel cell stack is compressed, the membrane electrode assembly 14 is compressed. Here, first pillar 1412 and second pillar 1422 are each elastically flattened, so that first height 1414 and second height 1424 are reduced, for example, from an exemplary value of 350 μm to a value of, for example, 260 μm-280 μm. Thus, first and second pillars 1412 , 1422 , in conjunction with third pillar 1524 , have a corresponding spring effect, which replaces an additional hardware spring of fuel cell stack 10 .

[0050] As an example, the height of anode plate 1510 is configured to have a value of 150 μm, but the present invention is not limited to this value. Furthermore, the height of the third pillar is exemplarily 200 μm, while the widths of third pillar 1524, second pillar 1422, and first pillar 1412 are all exemplarily 500 μm. These dimensions represent optimized implementation variants.

[0051] The structural integrity of the membrane electrode assembly 14 and the fuel cell stack 10 described in this case was quantified using the finite element method. When the membrane electrode assembly 14 is compressed by approximately 204 μm (corresponding to an applied pressure of 1.15 MPa), a contact pressure of 200 kPa is obtained at the interface between the gas diffusion layers 1410, 1420 and the membrane structure 140, which corresponds to high performance. The maximum induced tensile stress on the third contact surface 1525 of the cathode plate 1520 of the bipolar plate 15 is 0.16 MPa. In the event of a lateral offset of the cathode plate 1520 relative to the anode plate 1510 (as often occurs due to tolerances during manufacturing), the maximum induced tensile stress is 3.5 MPa at a lateral offset of 250 μm. Furthermore, numerical fluid dynamics (CFD) was used to determine the following pressure drops for the working medium flow field in the gas diffusion layers 1410 and 1420 and the coolant field in the coolant channels: 350 mbar for oxygen, 130 mbar for hydrogen, and 500 mbar for the coolant. Further optimizations can be achieved by improving the shape of these pillars. The obtained values ​​demonstrate, using experimental data, the improved structural integrity of the proposed membrane electrode assembly 14 and the proposed fuel cell stack 10.

[0052] In other embodiments, third structuring 1523 can also be formed on the coolant side of anode plate 1510. In this case, cathode plate 1520 is flat on both sides, thus also creating an internal coolant flow field. Alternatively, bipolar plate 15 can be formed integrally. Carbon-based materials or mixtures with metals can be used as materials.

[0053] Reference Signs List

[0054] 100 Fuel Cell Systems

[0055] 10 Fuel Cell Stack

[0056] 11 single battery

[0057] 12 Anode area

[0058] 13 Cathode region

[0059] 14 Membrane Electrode Assembly (MEA)

[0060] 140 membrane structure (membrane layer, anode layer, cathode layer)

[0061] 1410 Anode side gas diffusion layer

[0062] 1411 First Structuralization

[0063] 1412 First Column

[0064] 1413 First contact surface

[0065] 1414 First Height

[0066] 1415 First Plinth

[0067] 1416 First base height

[0068] 1420 Cathode side gas diffusion layer

[0069] 1421 Second Structuralization

[0070] 1422 Second Column

[0071] 1423 Second contact surface

[0072] 1424 Second Height

[0073] 1425 Second Pedestal

[0074] 1426 Second base height

[0075] 15 Bipolar plates (diaphragm plates, flow field plates)

[0076] 1510 Anode Plate

[0077] 1511 Anode side

[0078] 1520 cathode plate

[0079] 1521 cathode side

[0080] 1522 Coolant side

[0081] 1523 Third Structuralization

[0082] 1524 The Third Column

[0083] 1525 Third contact surface

[0084] 20 Anode supply device

[0085] 21 Anode supply path

[0086] 22 Anode exhaust gas path

[0087] 23 Fuel Tank

[0088] 24 Adjustment device

[0089] 25 Fuel recirculation pipe

[0090] 26 Conveying device

[0091] 30 Cathode supply device

[0092] 31 Cathode supply path

[0093] 32 Cathode exhaust gas path

[0094] 33 compressor

[0095] 34 motors

[0096] 35 Power Electronics

[0097] 36 turbines

[0098] 37 Exhaust valve pipe

[0099] 38 Adjustment device

[0100] 39 Humidifier

[0101] S Stacking direction.

Claims

1. A fuel cell stack (10), comprising a stack of bipolar plates (15) and membrane electrode devices (14) arranged alternately between two end plates, in, The membrane electrode device (14) comprises: - a membrane structure (140), the membrane structure having an anode layer, a cathode layer and a membrane layer, the membrane layer being located between the anode layer and the cathode layer; - an anode-side gas diffusion layer (1410) disposed on the anode layer; and - a cathode-side gas diffusion layer (1420) arranged on the cathode layer, At least one of the anode-side gas diffusion layer (1410) and the cathode-side gas diffusion layer (1420) has a structuring (1411, 1421) on a side facing away from the membrane structure (140), wherein the structuring comprises a plurality of columns (1412, 1422) for forming a laterally open flow field, wherein the columns (1412, 1422) have contact surfaces (1413, 1423) for receiving a bipolar plate (15), Wherein, the bipolar plate (15) comprises: - an anode plate (1510), the anode side (1511) of the anode plate facing the anode-side gas diffusion layer (1410) of the membrane electrode assembly (14), and - a cathode plate (1520), the cathode side (1521) of the cathode plate facing the cathode-side gas diffusion layer (1420) of the membrane electrode assembly (14), The anode-side gas diffusion layer (1410) has a first structure (1411) on a side facing away from the membrane structure (140), and the cathode-side gas diffusion layer (1420) has a second structure (1421) on a side facing away from the membrane structure (140), wherein the first structure (1411) includes a plurality of first columns (1412) for constructing a laterally open flow field, wherein the first columns (1412) have a first contact surface (1413) for placing a bipolar plate (15); and the second structure (1421) includes a plurality of second columns (1422) for constructing a laterally open flow field, wherein the second columns (1422) have a second contact surface (1423) for placing a bipolar plate (15), wherein at least one of the coolant sides (1522) of the anode plate (1510) or the cathode plate (1520) has a third structure (1523), and the third structure (1523) includes a plurality of third columns (1524) for constructing a laterally open coolant flow field, The third column (1524) is placed overlappingly with the first column (1412) and the second column (1422) of the membrane electrode device (14) along a stacking direction (S).

2. The fuel cell stack (10) according to claim 1, characterized in that The first pillars (1412) and the second pillars (1422) are positioned such that for each first pillar (1412), there is a second pillar (1422) positioned oppositely with respect to the membrane structure (140).

3. The fuel cell stack (10) according to claim 1 or 2, characterized in that The first pillar (1412) has a first height (1414), and the second pillar (1422) has a second height (1424), wherein the first height (1414) and / or the second height (1424) is 250-450 μm.

4. The fuel cell stack (10) according to claim 3, characterized in that The first height (1414) and / or the second height (1424) is 300-400 μm.

5. The fuel cell stack (10) according to claim 3, characterized in that The first height (1414) and / or the second height (1424) is 350 μm.

6. The fuel cell stack (10) according to claim 1 or 2, characterized in that The anode side (1511) of the anode plate (1510) and / or the cathode side (1521) of the cathode plate (1520) are designed to be flat.

7. The fuel cell stack (10) according to claim 1 or 2, characterized in that: Either the anode plate (1510) or the cathode plate (1520) is designed to be flat on both sides.

8. A vehicle comprising a fuel cell system (100) comprising a fuel cell stack (10) according to any one of claims 1 to 7.

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