DE102016118346A1 - Cathode supply for a fuel cell - Google Patents

Abstract

The invention relates to a cathode supply (30) for a fuel cell (10) of a fuel cell assembly (1), comprising a cathode supply path (31) and a cathode exhaust path (32), to / on the cathode supply path (31) a cathode compressor (33) is fluid-mechanically coupled / coupled, and the cathode supply (30) comprises a cathode recirculation line (110), by means of which the cathode supply path (31) with the cathode exhaust path (32) is fluid-mechanically coupled, wherein on / in the cathode recirculation line (110) is fluidically coupled / uncoupled to a recirculation water separator (121). The fluid-mechanical coupling of the cathode exhaust path (32) with the cathode supply path (31) through the cathode recirculation line (110) is by means of an exhaust gas recirculation actuator (111) on / in the cathode supply (30), in particular the cathode recirculation line (110) downstream or upstream of the recirculation water separator (121). The cathode recirculation line (110) is free from a turbomachine and / or the cathode supply (30) has the cathode compressor (33) as the only compressor on / in the cathode supply path (31).

Description

The invention relates to a cathode supply for a fuel cell of a fuel cell assembly, comprising a cathode exhaust path and a cathode supply path, wherein on / in the cathode supply path, a cathode compressor fluid-mechanically coupled / coupled. Furthermore, the invention relates to a fuel cell assembly, a fuel cell system and / or a fuel cell vehicle with a fluid supply to this connected or connected according to the invention cathode supply.

A fuel cell of a fuel cell assembly of a fuel cell system uses an electrochemical reaction of a hydrogen-containing (H, H ₂ ) fuel with oxygen (O, O ₂ ) to form water for generating electrical energy. For this purpose, the fuel cell contains as a core component at least one so-called membrane electrode assembly (MEA, Membrane Electrode Assembly), which is a structure of an ion-conducting or proton-conducting membrane and electrodes arranged on both sides of the membrane, an anode electrode and a cathode electrode. In addition, gas diffusion layers (GDL) can be arranged on both sides of the membrane-electrode assembly on the sides of the electrodes facing away from the membrane.

In general, the fuel cell is formed by means of a plurality of arranged in a stack (English stack) membrane electrode assemblies, wherein add their electrical power in an operation of the fuel cell. Bipolar plates, also called flux field plates or separator plates, are usually arranged between the individual membrane electrode units, which supply and usually also supply the membrane electrode units, ie a supply of the individual cells of the fuel cell, with the operating media, the so-called reactants serve a cooling of the fuel cell. In addition, the bipolar plates provide for a respective electrically conductive connection to the respective adjacent membrane-electrode units.

In an operation of the individual cells of the fuel cell (single cell: membrane electrode assembly and an associated anode space bounded by a bipolar plate and an associated cathode space bounded by a second bipolar plate), the fuel, a so-called anode operating medium, via an anode side open flow field of the bipolar plates supplied to the anode electrodes, where an electrochemical oxidation of H ₂ to 2H ^{+ occurs} with a release of electrons (2e ^- ) (H ₂ => 2H ⁺ + 2e ^- ). Through the membranes or electrolytes of the membrane-electrode units, which gas-tightly separate and electrically isolate the respective reaction spaces (anode space-cathode space pairs of the individual cells), a water-bound or anhydrous transport of the protons (H ⁺ ) formed by the anode electrodes ( (composite) anode of the fuel cell) in the anode spaces of the single cells to the cathode electrodes ((composite) cathode of the fuel cell) in the cathode spaces of the single cells.

The electrons provided at the anode are fed via electrical lines and an electrical load (electric traction motor, compressor, air conditioning et cetera) of the cathode. An oxygen-containing cathode operating medium is supplied to the cathode electrodes of the cathode via a cathode field open flow field of the bipolar plates, wherein an electrochemical reduction of O ₂ to 2O ^2- takes place under a recording of electrons (½O ₂ + 2e ^- => O ^2- ). At the same time, the oxygen anions (O ^2- ) formed on the cathode electrodes react with the protons transported through the membranes or electrolytes to form water (O ^2- + 2H ⁺ => H ₂ O).

A fuel cell vehicle describes a vehicle, which is operated or operated to a large extent by an electrical energy of a fuel cell or a fuel cell stack of the fuel cell of a fuel cell assembly of the vehicle. Optionally, an energy store, in particular a rechargeable battery, may assist the fuel cell assembly to provide an electrical (traction) motor of the vehicle which generates torque for propulsion of the vehicle and, optionally, an electrical consumer with electrical energy. Further, it is possible for the fuel cell to assist the battery in driving the fuel cell vehicle.

An electrical voltage of a single cell should not exceed a limit value at a start and during operation of the fuel cell, since otherwise damage to the individual cells occurs. However, at certain starting states and / or low load points, the voltage may be above the limit, which is why an electric power of the individual cells or the fuel cell should be limited. Furthermore, a cathode air should be low in oxygen when parking the fuel cell. A method of being able to operate the fuel cell even at low load points and to be able to turn off its cathode with as little oxygen as possible is a so-called cathode recirculation. In this case, oxygen-poor cathode exhaust gas is supplied from a cathode outlet of the fuel cell to a cathode inlet of the fuel cell. By the return of the cathode exhaust gas is also recirculated liquid water. This water is a danger to a compressor (water hammer).

The DE 10 2014 002 323 A1 discloses a fuel cell assembly having at least one fuel cell comprising a cathode compartment and an anode compartment. The fuel cell unit has an exhaust air line from and an air supply line to the cathode space, wherein in the supply air line, a first, operable by electric motor compressor is fluid-mechanically coupled. Between the exhaust air line and the supply air line, a cathode recirculation line is set up, wherein a second compressor is fluid-mechanically coupled into the cathode recirculation line. The second compressor can be driven by an exhaust air turbine, which is coupled fluid-mechanically downstream of the cathode recirculation line in the exhaust air line. Upstream of the exhaust air turbine, a water separator can be fluid-mechanically coupled into the exhaust air line.

It is an object of the invention to be able to operate a fuel cell even at low load points, wherein an electrical voltage of an individual cell of the fuel cell should not exceed a limit value. Furthermore, it should be possible to turn off a cathode of the fuel cell oxygen poor. In this case, a turbomachine in a cathode supply of the fuel cell should be safe to operate. In particular, the turbomachine should be protected from a water hammer. Furthermore, a corresponding fuel cell assembly, a corresponding fuel cell system and / or a corresponding fuel cell vehicle should be specified.

The object of the invention is by means of a cathode supply for a fuel cell of a fuel cell assembly, with a cathode supply path and a cathode exhaust path, wherein on / in the cathode supply path, a cathode compressor fluid-mechanically coupled / coupled; and by means of a fuel cell assembly, a fuel cell system and / or a fuel cell vehicle; solved according to the independent claims. Advantageous developments, additional features and / or advantages of the invention will become apparent from the dependent claims and the following description.

The cathode supply according to the invention has a cathode recirculation line, by means of which the cathode supply path can be coupled in a fluid-mechanical manner to the cathode exhaust gas path, and according to the invention, a recirculation water separator is fluid-mechanically coupled to / in the cathode recirculation line. That is, on the one hand, the cathode exhaust path among other things opens on / in the cathode recirculation line and the cathode recirculation line on the other hand on / in the cathode supply path, with the cathode recirculation line between the cathode exhaust path and the cathode supply path to / into the Cathode supply is fluid-mechanically coupled / coupled. A discharge of a cathode exhaust gas into the environment can take place through an exhaust pipe.

In embodiments, the fluid-mechanical coupling of the cathode exhaust path to the cathode supply path through the cathode recirculation line is achievable by means of an exhaust gas recirculation actuator (see below) at the cathode supply, in particular the cathode recirculation line downstream or upstream of the recirculation water separator , According to the invention, in comparison with a conventional cathode water separator or with respect to a conventional cathode water separation module, a significantly reduced recirculation water separator or a significantly smaller recirculation water separation module in the cathode recirculation line results. This saves space and reduces costs.

In embodiments, the cathode supply is designed such that only in an active cathode recirculation by means of the recirculation water separator, a significant amount of liquid water is deposited, and / or in inactive cathode recirculation by means of the recirculation water separator no or a relatively small amount of liquid water is separable. Active cathode recirculation means that a cathode exhaust gas originating from the cathode exhaust path flows through the cathode recirculation line into the cathode supply path (exhaust gas recirculation actuator open), ie recirculates cathode exhaust gas. Conversely, by an inactive cathode recirculation is meant that the cathode exhaust gas is not recirculated (exhaust gas recirculation actuator closed), where appropriate, a small volume flow through a portion of the cathode recirculation line flows (leakage via a pressure control actuator on / in Cathode exhaust path through an aperture on / in a cathode water separation line, etc.).

In embodiments, the cathode supply as a single water separator has the recirculation water separator on / in the cathode recirculation line. That is, the cathode supply preferably has no further water separator in addition to the recirculation water separator. This also means that the cathode supply in particular in / on the actual cathode exhaust path no Has water separator. If necessary, this cathode exhaust path leads into the environment via an exhaust device or an exhaust system. In embodiments, the cathode recirculation line is free of a turbomachine, such as a compressor or a turbine.

In embodiments, the cathode recirculation line is fluid mechanically coupled to the cathode exhaust path upstream or downstream of a pressure regulating actuator; the cathode recirculation line is fluid mechanically coupled to the cathode supply path upstream of the cathode compressor; and / or the cathode recirculation line is fluid-mechanically coupled on the exhaust side downstream of a humidifier of the cathode supply to / in the cathode supply.

In embodiments, an exhaust gas recirculation actuator is fluid mechanically coupled / coupled to the cathode recirculation line. It is possible to set the exhaust gas recirculation actuator at an opening area between the cathode exhaust path and the cathode supply path and the cathode recirculation line, respectively. In this case, the exhaust gas recirculation actuating means is then provided on / in the cathode exhaust gas path and / or on / in the cathode recirculation line, or on / in the cathode supply path and / or on / in the cathode recirculation line.

In embodiments, the exhaust gas recirculation actuator means is fluidly coupled / coupled to the cathode recirculation line upstream or downstream of the recirculation water separator. An exhaust gas recirculation actuator downstream of the recirculation water separator allows the use of a fixed, slightly open actuator (for example, a shutter), which can be dispensed with an actuator for the actuating means, as well as its hardware and software peripherals. In embodiments, directly or indirectly, a cathode water separation line is fluid mechanically coupled to the recirculation water separator; and / or downstream of the recirculation water separator, a water separation actuator is fluidly coupled to / coupled to the cathode water separation conduit.

In embodiments, the recirculation water separator is fluidly coupled / coupled to or into the cathode water separation line. In embodiments, the recirculation water separator is part of a recirculation Wasserabscheidemoduls, further comprising a recirculation water collector, optionally the Wasserabscheide-adjusting means, optionally at least a portion of the cathode Wasserabscheideleitung and optionally a recirculation water drain. Depending on how the water separation module is constituted, it may substitute the above recirculation water separator on the cathode water separation line. In embodiments, a downstream orifice of the cathode water separation conduit opens downstream or upstream of the pressure regulator actuator at the cathode supply; and / or the cathode water separation line opens in the cathode exhaust path, in an exhaust device or the recirculation water drain.

In embodiments, the water separation adjusting means is designed as an essentially permanently fixed, open adjusting means with a comparatively small flow cross section. In embodiments, such a Wasserabscheide-adjusting means as a fixed orifice, a fixed throttle, a fixed set flap et cetera is formed, wherein the Wasserabscheide-adjusting means is designed as a permanent leakage device of the cathode supply. The permanent leakage device in this case has a fluid throttling effect, which limits the passage of a fluid (water, cathode exhaust gas) such that further pressure control or pressure regulation of the cathode supply with an actuating means, in particular a pressure control actuating means on / in the cathode exhaust path, is possible.

In embodiments, the recirculation water separator is part of a recirculation water separation module; the recirculation water separation module has a recirculation water collector; and / or the recirculation water separation module comprises the cathode water separation line, the exhaust device or the recirculation water drain the water separation actuator. By an enumeration is in embodiments a bullet point (usually after a semicolon beginning and / or ending with a semicolon), is any plurality of bullet points or all bullet points are feasible.

The invention is explained in more detail below with reference to exemplary embodiments with reference to the attached schematic and not to scale drawing. Sections, elements, components, units, schemes and / or components that have identical, univocal or analogous training and / or function are in the description of the figures (see below), the list of reference numerals, the patent claims and in the figures of the drawing with the same Reference number marked. A possible, in the description (description of the invention (see above), figure description) not explained, not shown in the drawing and / or not final alternative, a static and / or kinematic Inversion, a combination et cetera to the embodiments of the invention or a component, a scheme, a unit, a component, an element or a portion thereof can be further taken from the list of reference numerals.

In the invention, a feature (unit, component, section, element, component, function, etc.) may be positively, that is, present, or negative, that is, absent, with a negative feature not explicitly explained as a feature, if not It is important that it is absent. A feature of this specification may be applied not only in a specified manner and / or manner, but also in a different manner and / or manner (isolation, summary, substitution, addition, isolation, et cetera). In particular, it is possible to replace, add or omit a feature in the claims and / or the description based on a reference numeral and a feature assigned thereto, or vice versa, in the description, the list of reference numerals, the patent claims and / or the drawing. In addition, a feature in a claim can be interpreted and / or specified in more detail.

The features of this specification are also interpretable as optional features (given the (mostly unknown) state of the art); that is, each feature can be considered as an optional, arbitrary, or preferred, that is, as a non-binding, feature. Thus, a detachment of a feature, possibly including its periphery, from an embodiment possible, this feature is then transferable to a generalized inventive concept. The absence of a feature (negative feature) in one embodiment demonstrates that the feature is optional with respect to the invention. Furthermore, in the case of a type term for a feature, a generic term for the feature is also readable (possibly further hierarchical structure into subgenus, section et cetera), whereby, for example, taking into account equality and / or equivalence, a generalization of one or this feature is possible. - In the merely exemplary figures show:

1 a simplified block diagram of an embodiment of a fuel cell assembly of a fuel cell system according to the invention;

2 a simplified block diagram of a first embodiment of a cathode supply of the fuel cell assembly according to the invention with a Wasserabscheidemodul in a cathode recirculation;

3 a simplified block diagram of a second embodiment of the cathode supply according to the invention with the Wasserabscheidemodul in the cathode recirculation;

4 a simplified block diagram of a third embodiment of the cathode supply according to the invention with the Wasserabscheidemodul in the cathode recirculation; and

5 a simplified block diagram of a fourth embodiment of the cathode supply according to the invention with the Wasserabscheidemodul in the cathode recirculation.

The invention is based on embodiments of a cathode supply 30 for a fuel cell 10 a fuel cell unit 1 a fuel cell system of a fuel cell vehicle (passenger car, passenger transport vehicle, bus, ATV (English All Terrain Vehicle), motorcycle, commercial vehicle, (heavy) truck, construction vehicle, construction machine, special vehicle, rail vehicle) explained in more detail. However, the invention is not limited to the embodiments explained below, but is of a more fundamental nature, such as for example, to a cathode supply of another fuel cell assembly, such as a transport system or other means of transport, such as an aircraft, or to transportable or stationary fuel cell systems for generating of electrical energy can be applied.

In the drawing, only those portions of the fuel cell assembly 1 of the fuel cell vehicle, which are necessary for an understanding of the invention.

In particular, attention is drawn to a representation of a periphery of the fuel cell assembly 1 , Sensors, electronic, electrical and power electrical devices and / or facilities et cetera been largely waived. Although the invention has been described and illustrated in detail by preferred embodiments, the invention is not limited by the disclosed embodiments. Other variations can be deduced therefrom without departing from the scope of the invention.

The 1 shows a fuel cell aggregate 1 a fuel cell system according to a preferred embodiment of the invention. The fuel cell aggregate 1 is preferably part of the vehicle not shown in detail, in particular a motor vehicle or an electric vehicle (Fuel cell vehicle), which preferably has an electric traction motor, which by a fuel cell 10 of the fuel cell aggregate 1 can be supplied with electrical energy. The fuel cell system differs from the fuel cell aggregate 1 In particular by not shown power electrical, electrical and electronic devices and / or devices (converter, battery, inverter et cetera), an engine control unit (English ECU, Engine Control Unit) et cetera, which the fuel cell assembly 1 not included.

The fuel cell aggregate 1 includes as a core component the fuel cell 10 or a fuel cell stack 17 , Which or which preferably a plurality of stacked individual fuel cells 11 , below as single cells 11 designated, wherein the fuel cell stack 17 in a preferably fluid-tight stack housing 16 is housed (fuel cell 10 ). Every single cell 11 includes an anode compartment 12 and a cathode compartment 13 , wherein the anode compartment 12 and the cathode compartment 13 from a membrane (part of a membrane-electrode assembly 14 , see below), preferably an ion-conductive polymer electrolyte membrane, spatially and electrically separated from each other (see detail).

The anode rooms 12 and the cathode rooms 13 the fuel cell 10 each have a catalytic electrode (part of the respective membrane-electrode unit 14 , see below), that is, an anode electrode and a cathode electrode, each of which catalyzes a partial reaction (see above) of a fuel cell reaction. The anode electrode and the cathode electrode each comprise a catalytic material, for example platinum, which is preferably supported on an electrically conductive carrier material with a comparatively large specific surface, for example a carbon-based material.

A structure of a membrane and the associated electrodes is also called a membrane-electrode unit 14 designated. Between two such membrane-electrode units 14 (in the 1 is only a single membrane electrode assembly 14 indicated) is further a bipolar plate 15 arranged (in the 1 again merely indicated), which supply of operating media 3 . 5 into a relevant anode compartment 12 a first single cell 11 and a respective cathode compartment 13 a directly adjacent second single cell 11 serves and which, moreover, an electrically conductive connection between the two directly adjacent individual cells 11 realized.

Between a bipolar plate 15 and a directly adjacent anode electrode of a membrane-electrode assembly 14 is an anode room 12 and between a cathode electrode of the same membrane-electrode assembly 14 and a second bipolar plate directly adjacent thereto 15 is a cathode compartment 13 a single cell 11 (Anode space-cathode space pair 12 / 13 ) educated. Optionally, gas diffusion layers between the membrane-electrode assemblies 14 and the bipolar plates 15 be arranged. In the fuel cell 10 or in the fuel cell stack 17 So are membrane electrode units 14 and bipolar plates 15 alternately arranged or stacked (fuel cell stack 17 ).

To supply the fuel cell 10 or the fuel cell stack 17 with the operating media 3 . 5 has the fuel cell aggregate 1 or the fuel cell system on the one hand an anode supply 20 and on the other hand, a cathode supply 30 on.

The anode supply 20 includes an anode supply path 21 , which is a supply of an anode operating medium 3 , a fuel 3 , for example hydrogen 3 or a hydrogen-containing gas mixture 3 , in the anode rooms 12 the fuel cell 10 serves. For this purpose, the anode supply path connects 21 a fuel storage 23 or fuel tank 23 with an anode input of the fuel cell 10 , The anode supply 20 further includes an anode exhaust path 22 , which is an anode exhaust 4 from the anode chambers 12 through an anode output of the fuel cell 10 through. An established anode operating pressure on an anode side of the fuel cell 10 is preferably by means of an actuating means 24 in the anode supply path 21 adjustable.

In addition, the anode supply points 20 preferably an anode recirculation line 25 on which the anode exhaust path 22 with the anode supply path 21 fluid mechanically connects. A recirculation of the anode operating medium 3 , that is, the actually preferred to be fueled fuel 3 , is often set up, the most over-stoichiometric anode operating medium 3 the fuel cell 10 to be returned and used. This is on / in the fuel recirculation line 25 preferably a recirculation compressor 26 arranged, by means of which a recirculation can be realized and / or a recirculation rate is adjustable. A drive of the recirculation compressor 26 is preferably done by means of an electric motor 27 or a drive 27 , which in particular with a corresponding power electronics 28 Is provided.

The cathode supply 30 (see also the 2 to 5 ) includes a cathode supply path 31 which is the cathode spaces 13 the fuel cell 10 a cathode operating medium 5 for example, oxygen 5 or an oxygen-containing gas mixture 5 , preferably air 5 , feeds, which in particular from the environment 2 is sucked. The cathode supply 30 further includes a cathode exhaust path 32 , which is a cathode exhaust 6 , in particular an exhaust air 6 , from the cathode rooms 13 the fuel cell 10 through and this or this one of an optionally provided exhaust device 150 or exhaust system 150 supplies.

For a promotion and compression of the cathode operating medium 5 is at / in the cathode supply path 31 preferably at least one cathode compressor 33 arranged. In embodiments, the cathode compressor 33 as a solely electric motor driven cathode compressor 33 designed, the drive by means of an electric motor 34 or a drive 34 takes place, which preferably with a corresponding power electronics 35 Is provided. The cathode compressor is preferred 33 as an electrically driven turbocharger 33 (English ETC, Electric Turbo Charger) trained.

The cathode supply 30 can according to the in 1 illustrated embodiment, a wastegate 37 or a Waste Management 37 which or which the cathode supply path 31 or a cathode supply line with the cathode exhaust path 32 or a cathode exhaust pipe connects, so a cathode-side bypass for the fuel cell 10 represents. The wastegate 37 allows an increase in a volume flow of the cathode compressor 33 at substantially constant volume flow into the fuel cell stack 17 the fuel cell 10 into it. One in the wastegate 37 arranged adjusting means 38 or as a wastegate 38 trained actuating means 38 allows adjustment of a volume flow of the fuel cell 10 optionally immediate cathode operating medium 5 ,

All adjusting means 24 . 38 , ( 111 . 123 . 130 ; see below) of the fuel cell unit 1 can be designed as controllable, controllable or non-controllable valves, flaps, throttles, apertures et cetera. For insulation of the fuel cell 10 from the surroundings 2 or another object may be at least one further corresponding actuating means in the anode supply 20 and / or the cathode supply 30 , for example on / in an anode path 21 . 22 or a line of the anode path 21 . 22 , and / or on / in a cathode path 31 . 32 or a line of the cathode path 31 . 32 be arranged. For the cathode exhaust path 32 this can be the adjusting means 123 . 130 take.

The fuel cell aggregate 1 further preferably comprises a humidifier 39 on. The humidifier 39 On the one hand, this is on / in the cathode supply path 31 arranged it from the cathode operating medium 5 can be flowed through. On the other hand, the humidifier 39 such on / in the cathode exhaust path 32 arranged it from the cathode exhaust 6 can be flowed through. The humidifier 39 is in the cathode supply path 31 preferably downstream of the cathode compressor 33 and upstream of a cathode input of the fuel cell 10 , and in the cathode exhaust path 32 between a cathode output of the fuel cell 10 and one at / in the cathode exhaust path 32 provided adjusting means 130 (see the 2 to 5 ) arranged. A moisture transmitter of the humidifier 39 preferably has a plurality of membranes, which are often formed either flat or in the form of hollow fibers, optionally as a hollow fiber body.

Various further details of the fuel cell system or of the fuel cell aggregate 1 or the fuel cell 10 / of the fuel cell stack 17 , the anode supply 20 and / or the cathode supply 30 are in the 1 not shown for reasons of clarity. So can the humidifier 39 from the cathode supply path 31 and / or the cathode exhaust path 32 be bypassed by means of a bypass (adjusting means).

Furthermore, at / in the anode exhaust path 22 a water separator be installed, by means of which a from the relevant partial reaction of the fuel cell 10 resulting product water is condensable and / or separable and optionally in a water collector (Wasserabscheidemodul) for storing can be derived. Furthermore, the anode supply 20 alternatively or additionally to the cathode supply 30 analog humidifier 39 exhibit. Furthermore, the anode exhaust path 22 in the cathode exhaust path 32 or vice versa, the anode exhaust gas 4 and the cathode off-gas 6 optionally via the common exhaust device 150 can be dissipated. Moreover, in embodiments, the cathode operating medium 5 a on / in the cathode supply path 31 flow through the provided intercooler.

The fuel cell aggregate 1 further comprises a in the 1 exemplified and greatly simplified cooling medium supply 40 , which is a cooling circuit 40 includes, in which the fuel cell 10 integrated heat transfer is. The cooling circuit 40 includes a cooling medium supply path 41 , which of the fuel cell 10 a comparatively cool cooling medium 7 supplies, and further a cooling medium discharge path 42 that of the fuel cell 10 a comparatively warm cooling medium 8th dissipates. A promotion of the in the cooling circuit 40 circulating cooling medium 7 / 8th takes place preferably by means of at least one electromotive operated cooling medium pump 43 in the cooling circuit 40 , The cooling medium 7 / 8th , especially water 7 / 8th , a water-alcohol mixture 7 / 8th or a water-ethylene glycol mixture 7 / 8th is coolable by a radiator or main vehicle radiator in the cooling circuit, which usually has an air blower. An essentially anhydrous cooling medium 7 / 8th or a dielectric, non-aqueous cooling medium 7 / 8th , such as a thermal oil 7 / 8th , of course, is applicable.

According to the invention (see further the 2 to 5 ) indicates the cathode supply 30 a cathode recirculation circuit 100 on, wherein by a cathode recirculation line 110 through, the cathode supply path 31 with the cathode exhaust path 32 fluidmechanically connectable. The cathode recirculation line 110 on the one hand to the cathode exhaust path 32 and, on the other hand, to the cathode supply path 31 fluid mechanically connected, wherein by means of an actuating means 111 , also as exhaust gas recirculation actuator 111 referred to, on / in the cathode recirculation line 110 , a recirculatable mass flow of cathode exhaust gas 6 through the cathode recirculation line 110 at least on and off switchable. Optionally, the actuating means 111 further designed such that the recirculatable mass flow from the actuating means 111 can be controlled or regulated.

The cathode recirculation line 110 is preferably upstream of the cathode compressor 33 to the cathode supply path 31 fluid mechanically connected. And further, the cathode recirculation line 110 preferably downstream of the wastegate line 37 , and / or upstream of an actuator 130 , in particular a pressure control actuating means 130 , on / in the cathode exhaust path 32 to the cathode exhaust path 32 fluid mechanically connected. According to the invention, the cathode recirculation line 110 a recirculation water separator 121 on. Here, the actuating means 111 downstream (see the 2 to 4 ) or upstream (see the 5 ) of the recirculation water separator 121 at the cathode supply 30 or at / in the cathode recirculation line 110 be provided.

To the recirculation water separator 121 is indirectly or directly a cathode Wasserabscheideleitung 140 connected, the cathode water separation line 140 upstream of a water separation actuator provided thereon 123 as to a water collector 122 belonging to. This also means that the recirculation water separator 121 a component of a recirculation water collector 122 or a / the recirculation Wasserabscheidemoduls 120 can be. The recirculation water separation module 120 includes the recirculation water separator 121 , the recirculation water collector 122 and optionally the cathode water separation line 140 ,

A fluid outlet of the recirculation water separation module 120 or even the recirculation water separator 121 itself is a fluid inlet of the cathode water separation line 140 , A fluid outlet of the cathode water separation line 140 , that is, downstream of the water separation actuator 123 , can directly into the cathode exhaust path 32 downstream of the actuator 130 , in particular the pressure regulating actuating means 130 ( 2 and 4 ), into a recirculating water drain 142 ( 3 and 5 ) or directly into the exhaust system 150 or the exhaust system 150 lead.

The recirculation water separator 121 is preferably upstream of the exhaust gas recirculation actuator 111 at the cathode recirculation line 110 arranged ( 2 to 4 ). This will cause the exhaust gas recirculation actuator 111 protected against liquid water. By a higher fluid pressure and thus lower gas velocities at this position on / in the cathode recirculation line 110 Can the recirculation water separator 121 be made smaller. It is important that it is the cathode recirculation line 110 is and not a position compared to the exhaust gas recirculation actuator 111 is crucial. The water is via the separate water separation line 140 in the direction of the exhaust system 150 or exhaust system 150 directed ( 2 and 4 ). Alternatively, the water can also be used for separate recirculation drainage 142 be directed ( 3 and 5 ).

For controlling or regulating a mass flow of water and optionally cathode exhaust gas 6 is the water separation actuator 123 trained accordingly. Through the water separation actuator 123 can be ensured that in embodiments no open gas bypass to the actuating means 130 , in particular the pressure control actuating means 130 , arises.

The water separation actuator 123 but can also act as a solid water separator 123 be educated (see 4 ). The water separator panel 123 On the one hand, it has to be so small that it has such a strong fluid flow limits that further a pressure control by means of the pressure control actuator 130 is possible, on the other hand, the Wasserabscheide-iris 123 however, be so large that in the recirculation water separator 121 separated water can drain off. - Alternatively, the recirculation water separator 121 downstream of the exhaust gas recirculation actuator 111 at the cathode recirculation line 110 be arranged ( 5 ).

According to the invention is a recirculation water separator 121 in the cathode recirculation line 110 installed. This allows a size of a water separator in the cathode supply 30 be greatly reduced, since a recirculated mass flow is significantly smaller than a total mass flow of the cathode exhaust gas 6 ,

LIST OF REFERENCE NUMBERS

1

Fuel cell aggregate of the fuel cell system

2

Environment, air

3

Fluid, operating medium, reactant, in particular anode operating medium, actual fuel, preferably hydrogen or hydrogen-containing gas mixture, inflowing

4

Fluid, exhaust possibly including liquid water, in particular anode exhaust, outflowing

5

Fluid, operating medium, reactant, in particular cathode operating medium, preferably (ambient) air, flowing

6

Fluid, exhaust gas optionally including liquid water, in particular cathode exhaust gas, preferably exhaust air, outflowing

7

Fluid, cooling medium, cooling water (water, water-alcohol mixture, water-ethylene glycol mixture), anhydrous cooling liquid, inflowing, comparatively cool

8th

Fluid, cooling medium, cooling water, outflowing, comparatively warm

10

Fuel cell of the fuel cell unit 1 or the fuel cell system

11

Single cell with an anode electrode of the anode of the fuel cell 10 and a cathode electrode of the cathode of the fuel cell 10 , Single fuel cell

12

Anode compartment of a single cell 11

13

Cathode space of a single cell 11

14

Membrane electrode unit with preferably a polymer electrolyte membrane and an anode electrode and a cathode electrode and optionally in each case a carrier therefor

15

Bipolar plate, flow field plate, separator plate

16

Stack housing of the fuel cell 10

17

Fuel cell stack of the fuel cell 10

20

Fuel cell supply, anode supply, anode circuit of the fuel cell

10

or the fuel cell stack 10

21

Path, supply path, flow path, anode supply path

22

Path, exhaust path, flow path, anode exhaust path

23

Fuel storage, fuel tank with anode operating medium 3

24

Adjusting means, (on) controllable, (controllable), not controllable, in particular valve, flap, throttle, aperture et cetera

25

Fuel recirculation line

26

Fluid conveyor, (flow) compressor, recirculation compressor, compressor, pump with the motor 27 , Roots blower et cetera

27

(Electric) engine, drive with electric motor, if necessary including gearbox

28

Electronics, in particular power electronics for the motor 27

29

(Gas) jet pump, ejector

30

Fuel cell supply, cathode supply, cathode circuit of the fuel cell 10 or the fuel cell stack 10

31

Path, supply path, flow path, cathode supply path

32

Path, exhaust path, flow path, cathode exhaust path

33

Fluid / air conveyor, (flow) compressor, cathode compressor, compressor, pump with the motor 34 , Roots blower et cetera

34

Motor, electric motor, drive with electric motor, possibly including gearbox

35

Electronics, in particular power electronics for the motor 34

37

Wastegate, Waste Management

38

Adjusting means, (on) controllable, (controllable), not controllable, in particular valve, flap, throttle, aperture et cetera

39

Humidifier, humidity transmitter with humidity transmitter

40

Fuel cell supply, cooling medium supply, cooling circuit of the fuel cell

10

or the fuel cell stack 10

41

Path, inlet path, flow path, cooling medium inlet path

42

Path, drain path, flow path, cooling medium drain path

43

Coolant pump

100

Cathode recirculation

110

Cathode recirculation

111

Adjusting means, (on) controllable, (controllable), not controllable, in particular valve, flap, throttle, aperture et cetera, exhaust gas recirculation actuating means

120

Recirculation Wasserabscheidemodul

121

Recirculation water

122

Recirculation water collector

123

Adjusting means, (on) controllable, (controllable), not controllable, in particular valve, flap, throttle, aperture et cetera, Wasserabscheide-adjusting means

130

Adjusting means, (on) controllable, (controllable), not controllable, in particular valve, flap, throttle, aperture et cetera, pressure regulating actuating means

140

Cathode Wasserabscheideleitung

142

Recirculation water drain

150

Exhaust system, exhaust system

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 102014002323 A1 [0008]

Claims (10)

Cathode supply ( 30 ) for a fuel cell ( 10 ) of a fuel cell assembly ( 1 ), with a cathode supply path ( 31 ) and a cathode exhaust path ( 32 ), where on / in the cathode supply path ( 31 ) a cathode compressor ( 33 ) is coupled / coupled in a fluid-mechanical manner, and the cathode supply ( 30 ) a cathode recirculation line ( 110 ), by means of which the cathode supply path ( 31 ) with the cathode exhaust path ( 32 ) is coupled fluid-mechanically, characterized in that on / in the cathode recirculation line ( 110 ) a recirculation water separator ( 121 ) is coupled / disconnected fluid mechanically. Cathode supply ( 30 ) according to claim 1, characterized in that the cathode supply ( 30 ) is designed such that: only with an active cathode recirculation by means of the recirculation water separator ( 121 ) a significant amount of liquid water is separable; with inactive cathode recirculation by means of the recirculation water separator ( 121 ) no or a relatively small amount of liquid water is separable; and / or the cathode supply ( 30 ) as a single water separator the recirculation water separator ( 121 ) on / in the cathode recirculation line ( 110 ) having. Cathode supply ( 30 ) according to claim 1 or 2, characterized in that: the cathode recirculation line ( 110 ) is free of a turbomachine and / or the cathode supply ( 30 ) as the only compressor, the cathode compressor ( 33 ) on / in the cathode supply path ( 31 ) having. Cathode supply ( 30 ) according to one of claims 1 to 3, characterized in that: the cathode recirculation line ( 110 ) upstream or downstream of a pressure regulating actuator ( 130 ) with the cathode exhaust path ( 32 ) is coupled fluid-mechanically; the cathode recirculation line ( 110 ) upstream of the cathode compressor ( 33 ) with the cathode supply path ( 31 ) is coupled fluid-mechanically; and / or the cathode recirculation line ( 110 ) on the exhaust side downstream of a humidifier ( 39 ) of the cathode supply ( 30 ) to / in the cathode supply ( 30 ) is coupled / disconnected fluid mechanically. Cathode supply ( 30 ) according to any one of claims 1 to 4, characterized in that on / in the cathode recirculation line ( 110 ) an exhaust gas recirculation actuating means ( 111 ) is coupled / disconnected in a fluid-mechanical manner; and / or the / an exhaust gas recirculation actuating means ( 111 ) upstream or downstream of the recirculation water separator ( 121 ) to / in the cathode recirculation line ( 110 ) is coupled / disconnected fluid mechanically. Cathode supply ( 30 ) according to any one of claims 1 to 5, characterized in that the recirculation water separator ( 121 ) directly or indirectly a cathode water separation line ( 140 ) is coupled fluid-mechanically; and / or downstream of the recirculation water separator ( 121 ) a water separation actuator ( 123 ) to / in the cathode water separation line ( 140 ) is coupled / disconnected fluid mechanically. Cathode supply ( 30 ) according to one of claims 1 to 6, characterized in that a downstream mouth of the cathode water separation line ( 140 ) downstream or upstream of the pressure regulating actuator ( 130 ) on / in the cathode supply ( 30 ) opens; and / or the cathode water separation line ( 140 ) in the cathode exhaust path ( 32 ), in an exhaust device ( 150 ) or a recirculation water drain ( 142 ) opens. Cathode supply ( 30 ) according to any one of claims 1 to 7, characterized in that the water separation control means ( 123 ) as a substantially permanently fixed, open actuating means ( 123 ) is formed with a comparatively small flow cross-section. Cathode supply ( 30 ) according to one of claims 1 to 8, characterized in that: the recirculation water separator ( 121 ) a component of a recirculation Wasserabscheidemoduls ( 120 ); the recirculation water separation module ( 120 ) a recirculation water collector ( 122 ) having; and / or the recirculation water separation module ( 120 ) the cathode water separation line ( 140 ), the exhaust device ( 150 ) or the recirculation water drain ( 142 ) the water separation actuator ( 131 ) having. Fuel cell aggregate ( 1 ), Fuel cell system and / or fuel cell vehicle, characterized in that the fuel cell aggregate ( 1 ), the fuel cell system and / or the fuel cell vehicle a fuel cell ( 10 ) and a fluidically connected thereto cathode supply ( 30 ) according to one of claims 1 to 9.

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