DE102017215260A1 - Flap valve arrangement for a fuel cell system and fuel cell system with flap valve arrangement - Google Patents

Abstract

The present invention relates to a flapper valve assembly (50) for controlling a gas flow through a conduit (60) of a fuel cell system (100). Therein covers a flat extended and movably mounted damper blade (51) from a cross section of the line (60) in a closed position and releases it in an open position. The damper blade (51) has a main surface (52) pointing upwards in the closed position and having at least one depression (54). The invention further relates to a fuel cell system (100) with such a flap valve arrangement (50) and a fuel cell system (100) with a surface section (70) which points upwards in the installed position of the flap valve arrangement and directly adjoins the flap blade (51). 71) and at least one continuous sloping path between the damper blade (51) and a lowest point (72) of the recess (71).

Description

The invention relates to a flap valve arrangement for a fuel cell system, in particular an icing-proof flap valve arrangement. Moreover, the invention relates to a fuel cell system with a flapper valve assembly.

Fuel cells use the chemical conversion of a fuel with oxygen to water to generate electrical energy. For this purpose, fuel cells as a core component to a membrane-electrode assembly (MEA - membrane electrode assembly) with a membrane electrode assembly. The latter is formed by a proton-conducting membrane, PEM, on which catalytic electrodes are arranged on both sides. In this case, the membrane separates the anode space associated with the anode and the cathode space associated with each other from the cathode and electrically isolated. In addition, gas diffusion layers can be arranged on the non-membrane-facing sides of the electrodes.

During operation of the fuel cell, a hydrogen-containing fuel is supplied to the anode, at which an electrochemical oxidation of H ₂ to H ⁺ takes place with release of electrons. Via the electrolytic membrane, a water-bound or water-free transport of the protons H ⁺ from the anode space into the cathode space takes place. The electrons provided at the anode are supplied to the cathode via an electrical line. The cathode is supplied with an oxygen-containing operating medium, so that there is a reduction of O ₂ to O ₂ ^- taking the electrons. These oxygen anions react in the cathode compartment with the protons transported across the membrane to form water.

As a rule, a fuel cell stack is formed by a multiplicity of MEAs arranged in a stack (stack), the electrical powers of which accumulate. Bipolar plates are usually arranged between the membrane-electrode assemblies, which ensure a supply of the individual MEA with the reactants and a cooling liquid and act as an electrically conductive contact to the membrane-electrode assemblies.

The supply of the fuel cell stack with its operating media, ie the anode operating gas (for example hydrogen), the cathode operating gas (for example air) and the coolant, via main supply channels that enforce the stack in its entire stacking direction and of which the operating media on the bipolar plates, the single cells be supplied. In each membrane-electrode assembly and each bipolar plate at least two such main supply channels are available for each operating medium, one for the supply and one for discharging the respective operating medium.

In order to supply the fuel cell stack as a whole with the operating means, the fuel cell system has an anode supply for supplying and discharging the anode operating means, a cathode supply for supplying and discharging the cathode operating medium, and a coolant circuit. The anode supply includes an anode supply line for supplying the anode resource to the fuel cell stack and an anode exhaust gas line. It is also customary to arrange at least one recirculation line in the anode supply of the fuel cell system, in order to supply the hydrogen contained in the anode-side exhaust gas of the fuel cell stack again to the stack. The cathode supply includes a cathode supply line for supplying the cathode resource to the fuel cell stack and a cathode exhaust gas line. The lines of the anode supply, cathode supply and the coolant circuit are fluidly connected to the corresponding main supply channels of the fuel cell stack.

In the gas-carrying lines of the anode supply and / or the cathode supply flap valves are arranged to control the guided gas flow through the respective line. These flap valves are designed substantially like throttle valves and usually have a valve flap (damper blade) on. The valve flap can be transferred from a closed position, in which it covers a cross section of the gas line substantially completely, into an open position, in which it essentially completely releases the cross section of the gas line.

Common PEM must be operated with a minimum membrane moisture to achieve optimal efficiencies, which is why the cathode operating medium is moistened before entering the stack usually. Due to this and the water production in the stack itself, liquid water drops at the outlet of the fuel cell stack. This liquid water is guided along the wall of the lines and collected during operation of the fuel cell system by means of water separators. During a shutdown procedure of the stack is usually carried out a drying of the water and the lines. In the switched-off fuel cell system, however, further condensate can form, for example, by nocturnal cooling of the atmosphere. This condensate can collect on the flap valves of the system and freeze there, depending on the outside temperature. When the system starts malfunctions of the icy flap may occur.

Such malfunctions can lead to malfunctions and damage to the fuel cell system. Therefore, solutions are already known from the prior art for defrosting iced flap valves.

The DE 10 2008 058 716 A1 discloses a valve assembly for a fuel cell system having a metallic valve flap which, depending on position, can allow or block gas flow through a conduit. In order to melt ice formed between the valve flap and the conduit, a solenoid is disposed near the conduit to inductively heat the valve flap. These and other flap heaters are unable to prevent freezing of the flaps from the outset. In addition, the heating of the flap valves requires additional time and energy at system startup.

The DE 10 2013 011 373 A1 discloses splash guard elements which are intended to protect moving parts disposed in the lines of a fuel cell system from liquid wetting. Alternatively, water used for moistening is injected into the lines in a direction away from the moving parts. However, this solution does not protect against icing formed by condensate.

The invention is based on the object to mitigate or overcome the disadvantages of the prior art and to provide a frost-protected flap valve assembly and a fuel cell system with a frost-protected flap valve assembly.

This object is achieved by a flap valve arrangement for controlling a gas flow guided through a line of a fuel cell system. The flap valve arrangement according to the invention has a flatly extended and movably mounted damper blade which covers a cross-section of the conduit in a closed position, preferably completely covers and particularly preferably substantially completely covers, and releases in an open position, preferably completely free and particularly preferably substantially completely free.

Preferably, the damper blade is designed monolithic and adapted exactly to a cross section of the line. Alternatively, the damper blade has a main body and an elastic seal surrounding the main body, which at least substantially fluid-tightly closes a region between the duct and a circumference of the main body in the closed position of the damper blade. Preferably, the base body of the damper blade is at least partially made of a metal or a thermosetting plastic. Further preferably, the damper blade is arranged on a flap shaft, preferably arranged rotationally fixed, and by means of this pivotable between the closed position and the open position. The flap shaft is preferably passed through a wall of the conduit and provided with corresponding sealing means.

The conduit is either part of the flapper valve assembly or part of the fuel cell system. If the conduit is part of the fuel cell system, the flap valve assembly essentially comprises the damper blade including bearing elements, the means for displacing the damper blade and sealing means. As part of the flap valve arrangement, the line is preferably a valve housing which is designed for insertion into a line of a fuel cell system and for this purpose contains, for example, a first connecting piece, a second connecting piece and a line piece connecting the connecting piece. Preferably, the damper blade is then disposed within the conduit section.

The damper blade has a first main surface pointing upwards in the closed position, and preferably in the installed position of the damper valve arrangement in the fuel cell system, and a second main surface lying opposite the first main surface. In this case, pointing upward indicates that a sum or an integration over all normal vectors of the first main surface results in a summation normal vector which points in a solid angle direction of 45 degrees, preferably 30 degrees and more preferably 15 degrees. Vertical upwards means opposite to the local direction of gravitational acceleration.

According to the present invention, the first main surface has at least one recess. The flap valve arrangement according to the invention thus advantageously has the effect that condensate collecting on the damper blade or on the walls of the duct can not collect in a contact region of damper blade and duct. Instead, the resulting condensate runs into the recess of the first main surface and freezes there if necessary. Even in the case of icing the damper blade thus remains fully mobile. Preferably, the means for displacing the damper blade are designed so that they can reliably move the damper blade with ice loading. Frozen condensate in the depression can be defrosted during normal operation of the fuel cell system and removed via the line.

In a preferred embodiment of the flap valve assembly, the first major surface has at least one continuous sloping path between at least one point of its circumference and a lowest point of the recess. Steady is there not strictly mathematical, but merely means that the first major surface has a negative slope (slope) at each point of each connection from a point of its circumference to the lowest point of the depression. This ensures that liquid water always runs in the direction of the depression.

Particularly preferably, the first main surface has a concave shape, in particular a concave shape rotationally symmetrical around the lowest point. Alternatively, an asymmetrical concave shape is adapted to the alignment of a sum normal vector of the first major surface such that condensed liquid water reliably drains into the recess in a closed position of the valve blade and is reliably ejected from the recess in an open position of the valve. Also preferably, the second major surface has a convex shape. Alternatively preferably, the damper blade is designed as a cylinder segment with a flat base surface (second main surface) and concave top surface (first main surface).

As an alternative to the concave shape of the first main surface, it has a plurality of segments between its circumference and the lowest point of the depression. Each segment has a negative slope as described above. However, the magnitude and orientation of the negative slope may vary between individual segments. Preferably, the negative increase in the radial direction increases inwardly first and then from, so that the recess has a total bell shape.

Also preferably, segments of the first major surface in the circumferential direction, for example, a circular valve leaf, a negative increase. Thus, condensate first runs in the circumferential direction along the slope and then collected in the direction of the lowest point of the depression. Further preferably, the first major surface has a plurality of depressions, with a steadily decreasing path existing between each point of the perimeter of the valve blade and a lowest point of at least one well.

In a likewise preferred embodiment of the flap valve arrangement according to the invention, the first main surface of the flap blade has a hydrophilic coating. Thus, the accumulation of water, whether by inflow or by condensation, is favored in the region of the first main surface of the damper blade. Also preferably, an inner surface of the conduit, at least in the region of the damper blade, in particular in a region above the first main surface of the damper blade, a hydrophobic coating on. Thus, the sliding of liquid from the inner pipe surface to the damper blade and its recess is favored. The line and / or the damper blade, in particular its base body, at least partially made of a metallic or thermosetting material. The person skilled in the art is aware of suitable hydrophilic or hydrophobic coatings for these materials.

The invention likewise provides a fuel cell system with a fuel cell stack, a multiplicity of fuel cells, a cathode supply, and a flap valve arrangement according to the invention arranged in the cathode supply or the anode supply, as described above. Preferably, the first main surface of the damper blade in the installed position of the damper valve assembly in the fuel cell system upwards.

Likewise provided by the invention is a fuel cell system with a fuel cell stack, a plurality of fuel cells, a cathode supply and an anode supply. The fuel cell system further includes a flapper valve assembly for controlling a gas flow passing through a conduit of the cathode supply or the anode supply. The flap valve assembly has a flat extended and movably mounted damper blade which covers a cross section of this line in a closed position, preferably completely covers, and particularly preferably substantially completely covers, and which releases a cross section of this line in an open position, preferably completely free and most preferably substantially completely free.

According to the invention, a surface section of the line pointing upward in the installation position of the flap valve arrangement in the fuel cell system and directly adjoining the flap leaf of the flap valve arrangement has at least one depression. This embodiment of the invention is particularly suitable for mounting positions of flap valves, in which neither the first nor the second main surface of the valve leaf in the closed position faces upwards, such as in substantially horizontally oriented lines.

The surface portion has at least one continuous sloping path between the damper blade and a lowest point of the recess. The fuel cell system according to the invention thus has the advantage that condensate collecting on the damper blade or on the walls of the duct can not collect in a contact region of damper blade and duct. Instead, the resulting condensate runs into the depression of the upwardly facing surface section and freezes there if necessary. Thus, the damper blade itself remains in Case of icing fully mobile. Frozen condensate located in the depression is defrosted during normal operation of the fuel cell system and can be discharged from the depression by means of the gas flow. Alternatively, the surface portion on a drain valve or is itself a movably mounted insulated component.

In this case, pointing upward indicates that a sum or an integration over all normal vectors of the surface section results in a summation normal vector which points in a solid angle direction of 45 degrees, preferably 30 degrees, particularly preferably 15 degrees. Vertical upwards means opposite to the local direction of gravitational acceleration. The steadily descending path is not to be understood as continuous in the mathematical sense. Continuously sloping merely means that the surface portion has a negative slope at each point of each connection of its edge region immediately adjacent to the damper blade towards the lowest point of the depression. This ensures that liquid condensate flows in the direction of the recess.

Particularly preferably, the surface portion has a concave shape. As an alternative to the concave shape of the surface portion, it may have a plurality of segments between its edge region immediately adjacent to the damper blade and the lowest point of the depression. Each segment has a negative slope. Strength and orientation of the negative slope may vary between individual segments. Also preferably, the first major surface has a plurality of depressions, each having a steadily decreasing path between each point of an edge region of the surface portion immediately adjacent to the valve leaf and the lowest point of at least one depression.

Also preferably, the surface portion of the line, analogous to the damper blade itself, movably mounted and transferred from an open position to a closed position. In the closed position, the surface section is flush and fluid-tight with the remaining inner surface of the line. In the open position, condensate collected in the depression flows into a reservoir located outside the conduit or to the environment.

Likewise preferably, the damper blade immediately adjacent to the surface section of the fuel cell system according to the invention has a hydrophobic coating. Thus, slippage of liquid droplets from the damper blade into the recess of the surface portion is promoted. Also preferably, the surface portion, at least in the region of the recess, on a hydrophilic coating. Thus, the accumulation of water, whether by inflow or by condensation, favors in the region of the depression. The line and / or the damper blade, in particular its base body, are formed from a metallic and / or thermosetting materials. The person skilled in the art is aware of suitable hydrophilic or hydrophobic coatings for these materials.

According to one embodiment of the fuel cell system according to the invention, the line having the surface portion is part of the flap valve arrangement. Particularly preferably, the line having the surface portion is part of a valve housing, which is designed for insertion into a line of the fuel cell system. The valve housing preferably has a first connecting piece, a second connecting piece and a piece of pipe connecting the connecting piece, wherein the surface portion is arranged in the line piece. Also preferably, the line having the surface portion is part of the fuel cell system but not the flapper valve assembly. The flapper valve assembly then essentially comprises the damper blade, a flapper shaft passed through a conduit wall, and corresponding sealing means. The surface portion is then disposed immediately adjacent the flapper valve assembly.

Particularly preferably, the recess of the damper blade of the above-described flap valve assembly and the recess of the surface portion of the fuel cell system described above, a volume which is adapted to a maximum in the disconnected fuel cell stack after a shutdown and / or drying procedure amount of condensate. In particular, the depression has a volume which is adapted to receive a maximum amount of condensate expected in the switched-off fuel cell stack after a switch-off and drying procedure. The amount in the switched-off fuel cell stack after a shutdown and / or drying procedure maximum expected condensate depends on a variety of factors. These factors include, for example, the operating state of the fuel cell system before shutdown, the outside temperature and the relative humidity of the surrounding outside air. In practice, the maximum amount of condensate expected for a given fuel cell system is easily determinable by a person skilled in the art, for example on the basis of experiments in a test stand.

Further preferred embodiments of the invention will become apparent from the remaining, mentioned in the dependent claims characteristics. The various embodiments of the invention mentioned in this application are, unless in individual cases executed differently, combined with advantage with each other.

• 1 eine schematische Darstellung eines Brennstoffzellensystems gemäß dem Stand der Technik;
• 2 eine schematische Darstellung einer Klappenventilanordnung gemäß einer Ausführungsform der Erfindung;
• 3 eine schematische Darstellung eines Brennstoffzellensystems gemäß einer Ausführungsform der vorliegenden Erfindung; und
• 4 eine schematische Darstellung eines Brennstoffzellensystems gemäß einer weiteren Ausführungsform der vorliegenden Erfindung.

The invention will be explained below in embodiments with reference to the accompanying drawings. Show it:

• 1 a schematic representation of a fuel cell system according to the prior art;
• 2 a schematic representation of a flap valve assembly according to an embodiment of the invention;
• 3 a schematic representation of a fuel cell system according to an embodiment of the present invention; and
• 4 a schematic representation of a fuel cell system according to another embodiment of the present invention.

1 shows a total of 100 designated fuel cell system according to the prior art. The fuel cell system 100 is part of a not further illustrated vehicle, in particular an electric vehicle having an electric traction motor, by the fuel cell system 100 is supplied with electrical energy.

The fuel cell system 100 comprises as a core component a fuel cell stack 10 containing a plurality of stacked single cells 11 having alternately stacked membrane-electrode assemblies (MEAs) 14 and bipolar plates 15 be formed (see detail). Every single cell 11 thus includes one MEA each 14 with an ion-conducting polymer electrolyte membrane (not shown here) and catalytic electrodes arranged on both sides. These electrodes catalyze the respective partial reaction of the fuel conversion. The anode and cathode electrodes are formed as a coating on the membrane and comprise a catalytic material, for example platinum, supported on an electrically conductive substrate of high specific surface area, for example a carbon based material.

As in the detailed representation of the 1 is shown between a bipolar plate 15 and the anode an anode compartment 12 is formed and is between the cathode and the next bipolar plate 15 the cathode compartment 13 educated. The bipolar plates 15 serve to supply the resources in the anode and cathode spaces 12 . 13 and further provide the electrical connection between the individual fuel cells 11 ago. Optionally, gas diffusion layers may be interposed between the membrane-electrode assemblies 14 and the bipolar plates 15 be arranged.

To the fuel cell stack 10 to supply with the resources, the fuel cell system 100 on the one hand, an anode supply 20 and on the other hand, a cathode supply 30 on.

The anode supply 20 of in 1 shown fuel cell system 100 includes an anode supply path 21 which feeds an anode resource (the fuel), for example hydrogen, into the anode spaces 12 of the fuel cell stack 10 serves. For this purpose, the anode supply path connects 21 a fuel storage 23 with an anode inlet of the fuel cell stack 10 , Adjusting the feed pressure of the anode operating medium into the anode compartments 12 of the fuel cell stack 10 via a metering valve 27.1 , The anode supply 20 further includes an anode exhaust path 22 containing the anode exhaust gas from the anode chambers 12 via an anode outlet of the fuel cell stack 10 dissipates.

In addition, the anode supply points 20 of in 1 shown fuel cell system 100 a recirculation line 24 on which the anode exhaust path 22 with the anode supply path 21 combines. The recirculation of fuel is common to the over-stoichiometric fuel used in the fuel cell stack 10 due. In the recirculation line 24 are a recirculation conveyor 25 , preferably a recirculation fan, as well as a flapper valve 27.2 arranged.

In the anode supply 22 The fuel cell system is further a water separator 26 installed to dissipate the product water resulting from the fuel cell reaction. A drain of the water separator can with the cathode exhaust gas line 32 be connected to a water tank or an exhaust system.

The cathode supply 30 of in 1 shown fuel cell system 100 includes a cathode supply path 31 which is the cathode spaces 13 of the fuel cell stack 10 supplies an oxygen-containing cathode resource, in particular air which is drawn in from the environment. The cathode supply 30 further includes a cathode exhaust path 32 , which the cathode exhaust gas (in particular the exhaust air) from the cathode compartments 13 of the fuel cell stack 10 dissipates and optionally this feeds an exhaust system, not shown.

For conveying and compressing the cathode operating means is in the cathode supply path 31 a compressor 33 arranged. In the illustrated embodiment, the compressor 33 as a mainly electric motor driven compressor 33 designed, the drive via a with a corresponding power electronics 35 equipped electric motor 34 he follows.

This in 1 shown fuel cell system 100 further includes an upstream of the compressor 33 in the cathode supply line 31 arranged humidifier module 39 on. The humidifier module 39 on the one hand is in the cathode supply path 31 arranged so that it can be flowed through by the cathode operating gas. On the other hand, it is so in the cathode exhaust path 32 arranged so that it can be flowed through by the cathode exhaust gas. A humidifier 39 typically has a plurality of water vapor permeable membranes formed either flat or in the form of hollow fibers. In this case, one side of the membranes is overflowed by the comparatively dry cathode operating gas (air) and the other side by the comparatively moist cathode exhaust gas (exhaust gas). Driven by the higher partial pressure of water vapor in the cathode exhaust gas, there is a transfer of water vapor across the membrane in the cathode operating gas, which is moistened in this way.

The fuel cell system 100 further includes a cathode supply line upstream and downstream of the humidifier 39 interconnecting humidifier bypass 37 with a flap valve disposed therein as a bypass actuator 38 on. Furthermore, flap valves 27.3 and 27.4 upstream of the fuel cell stack 10 in the anode supply line 31 or downstream of the fuel cell stack 10 in the anode exhaust gas line 32 arranged.

Various other details of the anode and cathode supply 20 . 30 are in 1 not shown for reasons of clarity. For example, the anode exhaust line 22 into the cathode exhaust gas line 32 lead, so that the anode exhaust gas and the cathode exhaust gas are discharged via a common exhaust system.

2 shows a schematic representation of a flap valve assembly 50 according to an embodiment of the invention. In the 2 shown flap valve assembly 50 is for example in the flap valve 27.5 realized that in the recirculation line 24 the anode supply 20 is arranged.

The flapper valve assembly 50 has a damper blade 51 on that in a pipe 60 of the fuel cell system 100 , For example, the recirculation line 24 , is arranged. Alternatively, the line can also be a line section of a valve housing (not shown), the valve housing being connected by means of a first and second connection piece into a line of the fuel cell system 100 , For example, the recirculation line 24 , is integrated.

The damper blade 51 is movably mounted and can by means of a flap shaft 57 and a servomotor 58 be moved between an open position (not shown) and a closed position. As in 2 represented covers the damper blade 51 in the closed position, the cross section of the line 60 Completely. By a rotation around the flap shaft 57 For example, the damper blade can be moved to the open position in which it is aligned substantially parallel to the image plane.

The damper blade 51 has a first main surface 52 and one of the first main surface 52 opposite second major surface 53 on. The first main surface 52 points in the closed position of the valve leaf 51 and in the installation position of the flap valve assembly 50 in the fuel cell system 100 upwards. In the 2 illustrated first main surface 52 also has a concave shape and thus one over the entire width of the line 60 trained deepening 54 on.

Due to the concave shape of the first main surface 52 exists between every point of a scope 55 the first main surface 52 and a lowest point 56 the depression 54 a steadily sloping path. condensate 80 , which adhere to the inner surface of the pipe 60 or directly on the first surface 52 of the valve leaf 51 separates, runs along such a steadily sloping path towards the lowest point 56 the depression 54 ,

Above the first main surface 52 of the valve leaf 51 arranged portions of the inner surface of the conduit 60 have a hydrophobic coating to prevent the drainage of condensate 80 towards the first main surface 52 to support. Furthermore, the first main surface has 52 a hydrophilic coating on the accumulation of condensate 80 in the depression 54 to favor.

Thus, the condensate 80 away from a contact area between damper blade 51 and direction 60 guided and thus away from the scope 55 the first main surface 52 , The damper blade 51 therefore remains fully mobile, even if the condensate 80 in the depression 54 freezes.

3 shows a schematic representation of a fuel cell system 100 according to an embodiment of the invention. The fuel cell system 100 has a line 60 as well as one in the line 60 arranged flap valve with a damper blade 51 on. The flap valve can for example as a valve 27.3 in the cathode supply line 31 of the pile 10 be realized.

The damper blade 51 is rotatably on a schematically illustrated flap shaft 57 stored and by means of this and the servomotor 58 between an open position (not shown) and a closed position pivotally. As in 3 illustrated, the damper blade covers a cross section of the line 60 completely in the closed position. The damper blade 51 and its main surfaces are oriented vertically in the closed position.

The in 3 illustrated section of the line 60 can be an integral part of a fuel cell system 100 be, for example, the anode supply line 31 , A flap valve arrangement of the fuel cell system according to the invention 100 then essentially comprises the damper blade 51 , the flap shaft 57 , the servomotor 58 and corresponding sealing means (not shown).

The in 3 illustrated section of the line 60 However, it may also be an integral part of a flapper valve assembly that is in a conduit of the fuel cell system 100 , For example, the anode supply line 31 , is fitted. The fitted flap valve arrangement may then comprise a valve housing having a first connection piece, a second connection piece and a line piece connecting the connection pieces. In this case, the section shown is the line 60 Part of this line piece and the first and second fittings (not shown) are in the anode supply line 31 arranged.

In any case, the line points 60 a surface section 70 on, directly to the damper blade 51 adjoins and in the installation position of the flap valve assembly in the fuel cell system 100 points upwards. The surface section 70 has a recess 71 on, according to the in 3 embodiment shown has a concave shape and thus over the entire width of the surface portion 70 extends.

Because the recess 71 directly to the damper blade 51 adjacent, exists at least one steadily sloping path between the damper blade 51 and a lowest point 72 the depression 71 , Along this at least one steadily sloping path runs condensate 80 that attaches to one of the surface section 70 facing major surface of the valve leaf 51 or directly in the surface section 70 separates, towards the lowest point 72 the depression 71 ,

The surface section 70 facing main surface of the valve leaf 51 has a hydrophobic coating to prevent the drainage of condensate 80 in the direction of the surface section 70 to support. Furthermore, the surface section 70 a hydrophilic coating on the accumulation of condensate 80 in the depression 71 to favor.

Thus, the condensate 80 away from a contact area between damper blade 51 and direction 60 passed and the damper blade 51 remains fully mobile, even if the condensate 80 in the depression 71 freezes. During operation of the fuel cell stack 10 becomes the condensate 80 by means of one in the line 60 guided gas flow from the well 71 discharged.

4 shows a schematic representation of a fuel cell system 100 according to a further embodiment of the invention. The fuel cell system 100 has a line 60 as well as one in the line 60 arranged flap valve with a damper blade 51 on. The flapper valve may, for example, as a valve 27.3 in the cathode supply line 31 of the pile 10 be realized. Already related to 3 explained aspects of the fuel cell system 100 or the flap valve assembly are in the description of 4 not repeated.

This in 4 shown fuel cell system 100 is different from the one in 3 shown by the surface section 70 the line 60 is also designed as a hinged flap. In particular, surface section 70 rotatably on the flap shaft 77 arranged and by means of the servomotor 78 between an open position (not shown) and a closed position pivotally. Instead of two servomotors 58 . 78 It is also possible to use a common positioning motor with corresponding valves and the flaps 51 . 70 connected is.

In the closed position, the pivotable surface section closes 70 flush and fluid tight with the remaining inner surface of the pipe 60 from. In the open position, an opening between the surface portion 70 and the remaining inner surface of the conduit 60 educated. Thus, in the open position condensate 80 that is in the closed position in the recess 71 has accumulated, out of the pipe 60 be applied.

QUOTES INCLUDE IN THE DESCRIPTION

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

Cited patent literature

• DE 102008058716 A1 [0010]
• DE 102013011373 A1 [0011]

Claims (10)

A flap valve assembly (50) for controlling a gas flow passing through a conduit (60) of a fuel cell system (100) a flatly extended and movably mounted damper blade (51) which covers a cross-section of the duct (60) in a closed position and releases it in an open position, wherein the damper blade (51) has a first main surface (52) pointing upwards in the closed position and having at least one depression (54). Flap valve arrangement (50) according to Claim 1 wherein the first major surface (52) has at least one continuous sloping path between at least one point of its periphery (55) and a lowest point (56) of the depression (54). Flap valve arrangement (50) according to Claim 1 or 2 , further comprising a second major surface (53) opposite the first major surface (52), the first major surface (52) having a concave shape and / or the second major surface (53) having a convex shape. Flap valve arrangement (50) according to one of the preceding claims, wherein the damper blade (51) on a flap shaft (57) rotatably disposed and pivotable by means of this between the closed position and the open position. Flap valve arrangement (50) according to one of the preceding claims, wherein the first main surface (52) has a hydrophilic coating and / or an inner surface of the conduit (60) at least in the region of the damper blade (51) has a hydrophobic coating. A fuel cell system (100) comprising a fuel cell stack (10) having a plurality of fuel cells (11), a cathode supply (30) and an anode supply (20); and a flap valve arrangement (50) arranged in the cathode supply (30) or the anode supply (20) according to one of the Claims 1 to 5 , Fuel cell system (100) after Claim 6 wherein the first main surface (52) of the damper blade (51) faces upward in the installed position of the damper valve assembly (50). Fuel cell system (100), comprising a fuel cell stack (10) having a plurality of fuel cells (11), a cathode supply (30) and an anode supply (20); a flap valve arrangement for controlling a gas flow guided through a line (60) of the cathode supply (30) or the anode supply (20) with a flatly extended and movably mounted damper blade (51) which covers a cross section of the duct (60) in a closed position and in an open position, wherein a surface portion (70) of the conduit (60) facing upward in the installed position of the flap valve assembly and immediately adjacent to the damper blade (51) has at least one depression (71) and at least one continuous sloping path between the damper blade (51) and a lowest point (72 ) of the recess (71). Fuel cell system (100) after Claim 8 wherein the damper blade (51) has a hydrophobic coating and / or the surface portion (70) has a hydrophilic coating. Fuel cell system (100) according to one of Claims 6 to 9 wherein the depression (54, 71) has a volume which is adapted to a maximum amount of condensate (80) to be expected in the switched-off fuel cell stack after a switch-off and / or drying procedure.

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