Fuel cell system

Abstract

Fuel cell system (1) with at least one fuel cell (4) and a humidification device (3) for humidifying a supply air flow to a cathode chamber (6) of the fuel cell (4) by means of an exhaust air flow flowing from the cathode chamber (6) of the fuel cell (4), wherein the supply air flow and the exhaust air flow are separated from each other by membranes (27) permeable to water vapor, characterized in that an anode water separator (11), which is flowed through by exhaust gas from an anode chamber (5) of the fuel cell (4), is integrated into the humidification device (3).

Description

[0001] The invention relates to a fuel cell system with at least one fuel cell and a humidification device according to the type defined in more detail in the preamble of claim 1.

[0002] Fuel cell systems are generally known in the art. They can be based on a PEM fuel cell, for example, and can generate electrical power from hydrogen or a hydrogen-containing gas and atmospheric oxygen. This electrical power can then be used for various purposes. A preferred application of such fuel cell systems is their use in vehicles to generate electrical propulsion power.

[0003] Such fuel cell systems typically feature humidifiers, which generally humidify the supply air stream to a cathode chamber of the fuel cell to prevent the relatively sensitive membranes of the PEM fuel cell from drying out and to ensure their long-term functionality. An example of such a humidifier is described in DE 101 10 419 A1. In addition to the humidifier itself, the system also features a water separator, through which water can be collected and injected into the supply air stream as auxiliary humidification.

[0004] A special design, which deals with the specific arrangement of the humidifier and water separator, is also described in DE 10 2008 005 649 A1.

[0005] In addition, DE 10 2007 003 144 A1 shows a structure in which the functions of humidification and cooling are integrated into a single component.

[0006] Product water is always produced during operation of a fuel cell system. This water must be drained from the system to ensure the gas supply and thus the functionality of the fuel cell. This water can be used in addition to humidifying the supply air using the humidifiers described above. Avoiding possible blockages caused by liquid water, especially in frozen form, requires considerable equipment, particularly during so-called freeze starts (i.e., starting the fuel cell system at temperatures below freezing), and during the warm-up of the fuel cell system. The setup typically includes electrical heating, for example, of drainage lines downstream of water separators and / or of valves arranged in these lines.In addition to the considerable energy expenditure, the setup and the necessary control system incur additional costs and increase the complexity and thus the susceptibility to failure of the fuel cell system. This is a significant disadvantage, particularly for fuel cell systems intended for use in vehicles to provide electric propulsion power. However, since these systems are frequently shut down in temperatures that could cause the system to freeze until restarted, this technical setup has so far been unavoidable.

[0007] The object of the present invention is to avoid or greatly simplify this apparatus design and thereby provide a cost-effective and energy-efficient fuel cell system.

[0008] According to the invention, this object is achieved by a fuel cell system having the features in the characterizing part of claim 1. Advantageous embodiments and further developments thereof emerge from the remaining dependent subclaims.

[0009] In the fuel cell system according to the invention, it is provided that the humidification device for humidifying the supply air flow using the moisture contained in the exhaust air flow has an integrated anode water separator through which exhaust gas from the anode chamber of the fuel cell flows. This integration of the anode water separator into the humidification device, which is otherwise flowed through by cathode-side volume flows, enables advantages in terms of installation space and weight. Furthermore, the fuel cell system according to the invention enables a simple integrated design in which water separated in the anode water separator can be easily diverted into one of the gas streams from or to the cathode chamber of the fuel cell, since these also flow through the integrated humidification device. Additional lines for such water, which would have to be correspondingly heated and / or insulated, can be dispensed with.

[0010] In another particularly favorable and advantageous embodiment of the fuel cell system according to the invention, it is further provided that a cathode water separator for the exhaust air flow is integrated into the humidification device. Such a cathode water separator can be particularly advantageous if the exhaust air flow after the humidification device reaches, for example, a turbine or an expander, where droplets should typically not arrive, as these could easily damage a very high-speed turbine, for example. Furthermore, in the event of freezing while the system is shut down, they could lead to a blockage of the expander or turbine, which significantly slows down restart. According to this sensible and advantageous embodiment, the cathode water separator can therefore be integrated into the humidification device in addition to the anode water separator.Here, too, complex water drainage lines, such as those that require electrical heating and / or insulation, can be dispensed with. Furthermore, the anode water separator can be connected to the cathode water separator, allowing water to be drained from the fuel cell system via a single, shared drain line.

[0011] A further advantageous embodiment of the fuel cell system according to the invention provides that at least one heat exchanger through which a cooling medium of a cooling circuit of the fuel cell flows is integrated into the humidification device. Such a heat exchanger, or for example two parallel heat exchangers through which flow is carried out, which are assigned to the actual humidifier and the water separator, or according to the embodiment described above, to the water separators, enable rapid heating and thawing of the humidification device as needed, for example, during a freeze-start. This allows the anode water separator and, if applicable, the cathode water separator, as well as the actual humidifier, to be quickly thawed and brought to operating temperature. Accordingly, electrical heaters can be dispensed with.In addition, it is possible to delay the cooling of the humidification device by connecting it to the cooling circuit, so that it is able to discharge separated water into the environment of the fuel cell system for a very long time.

[0012] In a further very favorable and advantageous variant of the fuel cell system according to the invention, it can be provided that the anode water separator is switchably connected to one or more components on the cathode side via at least one valve device. Such a valve device between the anode water separator and a component on the cathode side, for example a cathode water separator, if present, represents a very simple and efficient way to drain water within the humidification device and, if necessary, to drain gas from an anode recirculation into the area of ​​the supply air flow or the exhaust air flow on the cathode side. The design is highly integrated and very compact. It eliminates the need for lines that would need to be insulated and possibly heated.

[0013] In a very advantageous further development of this, it is further provided that the anode water separator is switchably connected to one or more components of the cathode side via at least two valve devices, wherein one of the valve devices branches off in the anode water separator such that a liquid volume flow primarily flows through it, and the other of the valve devices branches off in the anode water separator such that a gaseous volume flow primarily flows through it. By such a design with two valve devices in different regions of the anode water separator, the discharge of liquid and gas, which typically comprises residual hydrogen and inert gases that may have accumulated in an anode circuit, can be divided in the humidification device. In this way, the water can be metered to a different component of the cathode side than the gas.For example, the water can enter an exhaust air stream or a cathode water separator, while the gas can enter an air supply stream to the fuel cell, for example, in order to neutralize any residual hydrogen on the catalysts in the cathode chamber.

[0014] In a further very favorable and advantageous embodiment of the fuel cell system according to the invention, it is further provided that the fuel cell and the humidification device are integrated into a single structural unit, so that water from the anode water separator can flow into the cathode chamber of the fuel cell due to gravity when the valve device is open. Such a structure can introduce water and gas into the cathode chamber of the fuel cell without the need for lines, since the humidification device and fuel cell are integrated with one another in this advantageous development of the fuel cell system. The humidification device is arranged above the fuel cell in the direction of gravity such that a valve device for emptying the anode water separator introduces at least the water and, if applicable, the gas into the region of the cathode chamber of the fuel cell.Here, too, no heating or insulation is necessary, since the pipe elements connecting the components can largely be dispensed with.

[0015] Further advantageous embodiments of the fuel cell system according to the invention emerge from the remaining dependent claims. These will also become clear from the exemplary embodiments, which are described in more detail below with reference to the figures.

[0016] Showing: Fig. 1 a schematic diagram of a fuel cell system in a vehicle; Fig. 2 shows a first embodiment of a humidifying device according to the invention; Fig. 3 shows a second embodiment of a humidifying device according to the invention; Fig. 4 shows a third embodiment of a humidifying device according to the invention; Fig. 5 shows a fourth embodiment of a humidifying device according to the invention; Fig. 6 shows a fifth embodiment of a humidifying device according to the invention; Fig. 7 shows a sixth embodiment of a humidifying device according to the invention; Fig. 8 shows a seventh embodiment of a humidifying device according to the invention; and Fig. 9 a possible embodiment of the humidification device integrated with the fuel cell.

[0017] In the presentation of the Fig. 1 shows, very schematically, a fuel cell system 1 in a vehicle 2 which is indicated in principle. This fuel cell system 1, which is known per se, will be explained in more detail below, in order to then explain the functionality of an integrated humidification device 3, which is shown in the illustration of the Fig. 1 is not explicitly shown, in order to be able to explain in more detail.

[0018] The fuel cell system 1 in the representation of the Fig. 1 has, as its essential component, a fuel cell 4, which is to be designed as a stack of PEM fuel cells, a so-called fuel cell stack. The fuel cell 4 comprises an anode chamber 5 and a cathode chamber 6. The cathode chamber 5 is separated from the anode chamber 6 by the proton-conducting membranes 7, which are schematically indicated. Hydrogen is supplied to the anode chamber 5 as fuel. This hydrogen originates from a compressed gas reservoir 8 and reaches the anode chamber 5 via a valve device 9, which is schematically indicated and is designed as a metering and / or throttle valve. In the anode chamber 5, the hydrogen supplied to the anode chamber 5 is partially converted.Residual hydrogen, together with product water generated in the area of ​​the anode chamber 5 and inert gases, particularly nitrogen, diffused through the membranes 7 into the anode chamber, passes via an anode outlet 10 to an anode water separator 11 and from there via a recirculation line 12 to a recirculation conveyor 13, which returns the residual hydrogen and the inert gases in the exhaust gas, together with fresh hydrogen from the compressed gas storage 8, to the anode chamber 5. This structure, also known as anode recirculation, enables ideal utilization of the active area available in the anode chamber 5 due to the excess hydrogen metered into the anode chamber 5. Product water and inert gas then accumulate over time in the anode recirculation. To prevent the hydrogen concentration from falling below a critical limit, water and / or inert gases must be vented from time to time.This occurs via the anode water separator 11 and a valve device 14 arranged therein. This valve is also referred to as a drain / purge valve. In the embodiment shown here, the drained liquid and the drained gas pass through a drain line 15 into an air supply flowing to the cathode chamber 6 of the fuel cell 4. Separate drainage of water (drain) and gas (purge) via two separate valves would also be conceivable.

[0019] Air is supplied to the cathode chamber 6 of the fuel cell 4 via an air conveying device 16. The supply air, compressed in the area of ​​the air conveying device 16, passes through a charge air cooler 17 and a humidifier supply line 18 into a humidifier 19 or is partially or completely bypassed around the humidifier 19 via a bypass line 20 with a bypass valve 21. It then passes through a cathode supply line 22 into the cathode chamber 6. After the cathode chamber 6, the exhaust air flow passes through a cathode outlet 23 into the area of ​​the humidifier 19. In the humidifier 19, two areas 24, 25 for the supply air flow on the one hand and the exhaust air flow on the other are separated from one another by membranes 26 permeable to water vapor. The moisture contained in the exhaust air flow thus passes through these membranes 26 into the supply air flow and humidifies it. The humidifier 19 is therefore also called gas-gas humidifier 19.After flowing through the area 25 of the humidifier 19, the exhaust air stream enters the area of ​​a cathode water separator 27, in which liquid is separated from the exhaust air stream. Via a turbine feed line 28, the exhaust air stream then enters a turbine 29 and is expanded in the area of ​​this turbine 29. As a result, at least part of the pressure energy and thermal energy contained therein is recovered in the area of ​​the turbine 29. The structure can additionally have a burner or catalytic burner (not shown here) in order to recover further thermal energy, for example from hydrogen or from the residual hydrogen present in the discharge line 15, which is then also fed to the turbine 29 and serves to recover energy from the fuel cell system 1.

[0020] After the turbine 29, the turbine exhaust air flow is discharged into the environment via a turbine exhaust air line 30. Separated water can also be supplied to this turbine exhaust air line 30 via a further discharge line 31 and a valve device 32 in the area of ​​the cathode water separator 27. The cathode water separator 27 primarily serves to protect the turbine 29 from liquid droplets, preventing damage to the very high-speed turbine 29 from liquid droplets. Furthermore, liquid droplets could freeze in the area of ​​the turbine 29 if temperatures drop below freezing after the fuel cell system 1 or the vehicle 2 is shut down.

[0021] In the embodiment shown here, the turbine 29 is arranged on a shaft together with the air conveying device 16. An electric machine 33 is also located on this shaft. This structure is also referred to as an electric turbocharger or ETC (Electric Turbo Charger). The power generated in the area of ​​the turbine 29 is typically made available to the air conveying device 16. The remaining power required to drive the air conveying device 16 is provided via the electric machine 33. If the power generated in the area of ​​the turbine 29 exceeds that required to drive the air conveying device 16, the electric machine 33 can also be operated as a generator.

[0022] The fuel cell system 1 in the vehicle 2, which is schematically indicated here, also has a cooling circuit 34. The cooling circuit 34 is shown in a highly simplified manner in the exemplary embodiment shown here. It essentially consists of a cooling heat exchanger 35 for dissipating excess heat to the environment, a coolant delivery device 36, and line elements for conveying the liquid cooling medium. The liquid cooling medium is first guided via a fuel cell cooling line 37 through a heat exchanger 38 in the area of ​​the fuel cell 4 in order to dissipate excess waste heat. The cooling medium then reaches the aforementioned charge air cooler 17 via a line element 39, where it cools the supply air flow, which is hot after compression. The cooling medium then returns to the area of ​​the cooling heat exchanger 35. The cooling capacity can now be adjusted accordingly, for example, via the speed of the coolant delivery device 36.Of course, it would also be conceivable to bypass, for example, the cooling heat exchanger 35 or the charge air cooler 17 in whole or in part in individual situations or operating phases of the fuel cell system 1 using suitable bypass lines and valve devices in order to set the desired temperatures.

[0023] In addition to or as an alternative to cooling by the cooling medium of the cooling circuit 34, the charge air cooler 17 can also be cooled by the exhaust air flow from the area 25 of the humidifier 19 before it flows out of the system. This also provides cooling power. In systems with a turbine 29, the exhaust air flow is further heated, allowing more power to be recovered in the area of ​​the turbine 29.

[0024] The structure described here is known from the general state of the art. During operation of the fuel cell system 1, product water is produced, which is present in the form of vapor and liquid water in the gas streams on the anode and cathode sides. In order to prevent freezing or to delay it as long as possible when the fuel cell system 1 is shut down in the vehicle 2 at temperatures below freezing, complex insulation and / or heating systems, for example electrically heated line elements or the like, are necessary, particularly in the area of ​​the humidifier 19 and the anode water separator 11 or the cathode water separator 27. To reduce this equipment structure, the humidification device 3 already mentioned is proposed below, which, depending on the embodiment, combines numerous functionalities in a single integrated component.

[0025] In the presentation of the Fig. 2 shows a first embodiment of such a humidification device 3. The schematic representation of the humidification device 3 shows the gas-gas humidifier 19 with its two regions 24, 25 and the membranes 26 arranged therebetween. Furthermore, the bypass line 20 with the bypass valve 21 is located in the humidification device 3. Below the region 25 of the humidifier 19 are the anode water separator 11 and the cathode water separator 27. Part of the turbine exhaust air line 30 is mechanically connected to this structure of the humidification device 3. As already described above, the dry gas stream flows to the humidifier 19 via the humidification supply line 18 and, in a humidified state, is fed to the cathode chamber 6 via the cathode supply line 22. As a moisture supplier, the moist exhaust air flow from the cathode chamber 6 enters the integrated humidification device 3 via the cathode discharge 23.After flowing through the area 25 of the humidifier 19, the exhaust air stream enters the cathode water separator 27, and the exhaust air stream, freed of liquid water, can then flow through the turbine supply line 28 to the turbine 29 (not shown here). The turbine exhaust air stream reaches the environment via the turbine exhaust line 30, which here is partially mechanically connected to the integrated humidification device 3 or is integrated into it.

[0026] The anode water separator 11 and the cathode water separator 27 are arranged adjacent to one another. In the embodiment shown here, they are connected to one another via the valve device 14, so that water and / or gas can be discharged via the valve device 14 from the anode water separator 11, to which it has been supplied via the anode outlet 10, into the area of ​​the cathode water separator 27. Water collected in the cathode water separator 27 can then be drained off, similar to the illustration in Fig. 1, are discharged into the turbine exhaust air stream via the valve device 32. The structure is as shown in the exemplary illustration of the Fig. 2, the system is constructed in such a way that, when the valve device 14 is open, the liquid water flows from the anode water separator 11 into the cathode water separator 27 by gravity, and from there, when the valve device 32 is open, into the turbine exhaust air stream in the turbine exhaust air line 30. The integrated design eliminates the need for piping elements between the individual components. Accordingly, these piping elements cannot freeze or cool down and do not require insulation or heating.

[0027] The integrated humidification device 3 is also integrated into the cooling circuit 34 of the fuel cell system 1. This integration into the cooling circuit 34 can, for example, be in the area of Fig. 1 with 39 designated line element. This is shown in the illustration of the Fig. 2 as a dashed line element 39. Corresponding collectors 40 are connected to the cooling circuit 34 via the line element 39. In the exemplary embodiment shown here, two heat exchangers 41, 42, also shown in dashed lines, are located between the two collectors 40, through which flow occurs in parallel. The first heat exchanger 41 integrates the humidifier 19 of the integrated humidification device 3 into the cooling circuit 34; the other heat exchanger 42, which is divided into two sections with serial flow, integrates the two water separators 11, 27 of the anode and cathode, respectively, into the cooling circuit 34.This connection of the two water separators 11, 27 via the heat exchanger 42 parallel to the humidifier 19 via the heat exchanger 41 into the cooling circuit 34 of the fuel cell allows, on the one hand, rapid thawing of the individual sections of the integrated humidification device 3 in the event of a freeze-start, thus reducing the warm-up time, in particular of the humidifier 19, to operating temperature. In addition to this warm-up via the cooling water in the event of a freeze-start, the connection to the cooling water is also advantageous in that the integrated humidification device 3 cools down comparatively slowly when the fuel cell system 1 is shut down, particularly when the cooling circuit 34 is still operating. This is further supported by the comparatively large mass of the integrated humidification device 3 compared to its individual components.This allows liquid water to be kept liquid for a very long time and removed from the fuel cell system 1. In addition to the removal of the liquid water via the valve device 32 into the turbine exhaust air stream, the exhaust air itself, typically together with the residual hydrogen discharged into it via the valve device 14 from the anode chamber 5, will flow via the turbine feed line 28 to the turbine 29. As already mentioned, a burner or a catalytic burner can be arranged in the region of the turbine feed line 28. In this burner, the residual oxygen and residual hydrogen in the gas stream flowing to the turbine 29 would then react with one another. This prevents hydrogen emissions to the environment, and the thermal energy generated during catalytic combustion increases the power output of the turbine 29.

[0028] In the presentation of the Fig. 3 shows the integrated humidification device 3 in an alternative embodiment. The structure corresponds largely to that shown in Fig. 2. However, the bypass line 20 and the bypass valve 21 have been omitted here. Humidification can no longer be controlled via the bypass, but must be adjusted via other mechanisms—for example, air stoichiometry. The design thus saves space, weight, and individual components.

[0029] In the presentation of the Fig. 4 shows a further alternative embodiment of the integrated humidification device 3. Essentially, what has been said so far applies to it, in particular, it is essentially constructed in the same way as the humidification device shown in Fig. 2. The only difference is that the valve device 14 no longer leads from the anode water separator 11 to the cathode water separator 27, but directly into the turbine exhaust line 30. The advantage of this is the possibility of designing the cathode water separator 27 significantly smaller, thus saving installation space. The disadvantage is that not only water but also gases from the anode recirculation enter the turbine exhaust air stream via the valve device 14, thus potentially causing hydrogen emissions into the environment.

[0030] To prevent this, the presentation of the Fig. 5 shows a further alternative embodiment. It essentially corresponds to a combination of the two Fig. 2 and Fig. 4. The valve device 14 is again analogous to the embodiment described in Fig. 4. It primarily serves to drain water from the anode water separator 11 into the turbine exhaust line 30. A further valve device 43 is arranged between the anode water separator 11 and the cathode water separator 27 in such a way that the gas located in the area of ​​the anode water separator 11 can be drained into the cathode water separator 27. Here, too, the cathode water separator 27 can be further optimized in terms of installation space and is much smaller than in the structure according to Fig. 2, since the water from the two separators 11, 27 is discharged separately into the turbine exhaust line 30. Nevertheless, the discharged gas is fed via the cathode separator 27 to the turbine 29 and typically to a catalytic burner arranged upstream of it, so that hydrogen emissions are reduced, contrary to the Fig. 4 shown structure can be avoided here.

[0031] In the presentation of the Fig. 6, the structure of the integrated humidification device 3 is again similar to the illustration in Fig. 4. However, the valve device 14 does not lead from the anode water separator 11 into the area of ​​the turbine exhaust line 30, but into the area of ​​the cathode supply line 22, so that water and gas are led into the cathode chamber 6. Unlike in the Fig. 6, it may be advantageous if the structure is selected such that the water flows through the valve device 14 in the direction of the cathode supply line 22 due to gravity.

[0032] In the presentation of the Fig. 7, this structure is taken up again and supplemented by the already described valve device 43. The valve device designated here as 43, which connects the anode water separator 11 with the cathode supply line 22, is now to be described analogously to the explanations in Fig. 5, the gas collected in the anode water separator can be discharged into the cathode supply line 22. At the same time, the valve device 14 is again shown as a connection between the anode water separator 11 and the cathode water separator 27 and is primarily intended to discharge water collected in the anode water separator 11 into the cathode water separator 27, analogous to the explanations in the illustration in Fig. 2. Alternatively, it would of course also be conceivable to design the valve device 14 analogously to the embodiments in Fig. 5 in turn be arranged so that the water is fed directly into the turbine exhaust air line 30, so that the cathode water separator 27 can be designed correspondingly smaller.

[0033] In the presentation of the Fig. 8 shows a further alternative embodiment of the integrated humidification device 3. It completely dispenses with the cathode water separator 27, for example because there is no turbine downstream of the humidification device 3 in the direction of the exhaust air flow, which turbine must be protected from liquid water droplets. The structure is thus much more compact. The discharge of water and / or gas via the valve device 14 can take place directly from the anode water separator 11 into the area 25 of the humidifier 19 or its outlet. In addition, the integrated humidification device 3 in the illustration according to Fig. 8 has another special feature. This consists in the charge air cooler 17, which is integrated into the humidification device 8 and through which the cooling medium also flows, in addition to the heat exchangers 41 and 42 of the integrated humidification device 3. The charge air cooler 17 is connected to one of the collectors 40 or integrated into it.

[0034] Of course, it is conceivable to combine all of the described design variants and individual aspects of the designs. For example, it would be conceivable to omit the bypass line 20 and the valve device 21 in each of the described variants and / or to integrate the charge air cooler 17 accordingly. All other conceivable combinations are of course also possible and may be expedient in terms of operational management.

[0035] In the final Fig. 9 will again be the essentially in Fig. 6 described variant is taken up. As already described in the description of the Fig. 6, it would be useful if the discharge of the water (and the gas) via the valve device 14 could be effected by gravity, so that no unnecessary pressure is lost for blowing out the water from the anode water separator 11. Such a structure is schematically shown in the illustration of Fig.9. Here, the integrated humidification device 3 is integrated together with the fuel cell 4 in a single structure, so that the cathode supply line 22 can essentially be eliminated, and the humidified supply air flow, together with water and gas from the anode separator 11, passes directly into the cathode chamber 6 of the fuel cell 4, with the water originating from the anode water separator 11 flowing automatically into this area by gravity. Otherwise, the above-mentioned statements regarding the previous embodiments also apply here.For example, an integrated structure of fuel cell 4 and humidification device 3 in the manner described can also be carried out in such a way that only gases are conveyed to the cathode chamber 6 of the fuel cell 4 through the integrated supply line and the omission of the cathode supply line 22, while the water from the anode water separator 11 in turn passes via the valve device 14, for example, into the cathode water separator 27 and / or the exhaust air line 30 or directly into the exhaust air stream.

Claims

[1] Fuel cell system (1) with at least one fuel cell (4) and a humidification device (3) for humidifying a supply air flow flowing to a cathode chamber (6) of the fuel cell (4) by means of an exhaust air flow flowing from the cathode chamber (6) of the fuel cell (4), wherein the supply air flow and the exhaust air flow are separated from one another by membranes (27) permeable to water vapor, characterized by that an anode water separator (11), through which exhaust gas from an anode chamber (5) of the fuel cell (4) flows, is integrated into the humidification device (3). [2] Fuel cell system (1) according to claim 1, characterized by that a cathode water separator (27) for the exhaust air flow is integrated into the humidification device (3). [3] Fuel cell system (1) according to claim 1 or 2, characterized bythat a humidifier bypass line (20) with a valve device (21) around the actual humidifier (19) is integrated into the humidification device (3). [4] Fuel cell system (1) according to claim 1, 2 or 3, characterized by that at least one heat exchanger (41, 42) through which a cooling medium of a cooling circuit (34) of the fuel cell (4) flows is integrated into the humidification device (3). [5] Fuel cell system (1) according to one of claims 1 to 4, characterized by that a charge air cooler (17) for the supply air flow, which is cooled by a cooling medium and / or the exhaust air flow, is integrated into the humidification device (3). [6] Fuel cell system (1) according to one of claims 1 to 5, characterized bythat a turbine (29) is provided which is acted upon by the exhaust air flow, wherein a turbine exhaust air line (30) for a turbine exhaust air flow is mechanically connected to the humidification device (3) or is integrated therein. [7] Fuel cell system (1) according to one of claims 1 to 6, characterized by that the anode water separator (11) is switchably connected to one or more components of the cathode side via at least one valve device (14, 43). [8] Fuel cell system (1) according to one of claims 1 to 7, characterized bythat the anode water separator (11) is switchably connected to one or more components of the cathode side via at least two valve devices (14, 43), wherein one of the valve devices (14) branches off from the anode water separator (11) in such a way that a liquid volume flow primarily flows therethrough, and that the other of the valve devices (43) branches off in the anode water separator (11) in such a way that a gaseous volume flow primarily flows therethrough. [9] Fuel cell system (1) according to claims 2 to 8, characterized by that the anode water separator (11) is switchably connected to the cathode water separator (27). [10] Fuel cell system (1) according to one of claims 6 to 9, characterized by that the anode water separator (11) is switchably connected to the turbine exhaust air flow. [11] Fuel cell system (1) according to one of claims 1 to 10, characterized bythat the anode water separator (11) is switchably connected to the supply air flow. [12] Fuel cell system (1) according to one of claims 7 to 11, characterized by that the fuel cell (4) and the humidification device (3) are integrated into a structural unit, so that water from the anode water separator (11) can flow into the cathode chamber (5) of the fuel cell (4) due to gravity when the valve device (14) is open.

Images