Water separator for a fuel cell system, fuel cell system, and vehicle

Abstract

The technology disclosed here relates, according to the invention, to a water separator (11) for a fuel cell system (10), having a housing (12) with a housing volume (19), a gas inlet opening (13), a gas outlet opening (15) and a water outlet opening (17), having a valve arrangement with a valve seat (22) and a valve body (21), which is positioned in the housing volume (19), the valve arrangement being adjustable into an open state (S1) and into a closed state (S2), and having a bypass (23) which is integrated in the valve body (21) and has a bypass inlet opening (24), through which water (18) can flow into the bypass (23), and a bypass outlet opening (25), through which water (18) can flow out of the bypass (23) and into the surroundings of the housing (12), wherein the bypass (23) in the closed state (S2) is positioned in such a manner that water (18) can flow into the bypass inlet opening (24) only when a certain water level in the housing volume (19) is reached. The technology also relates to a fuel cell system (10) having the water separator (11), and to a vehicle (100) having the fuel cell system (10).

Description

[0001] Description

[0002] Water separator for a fuel cell system, fuel cell system and vehicle

[0003] The technology disclosed here relates to a water separator for a fuel cell system, a fuel cell system with a water separator and a vehicle with such a fuel cell system.

[0004] Known fuel cell systems typically comprise a fuel cell with an anode and a cathode. Furthermore, these systems each comprise an anode subsystem and a cathode subsystem. Typical functional components of a cathode subsystem include a compressor for compressing a cathode gas, a charge air cooler for cooling the compressed cathode gas, a humidifier for humidifying the cooled cathode gas and drying moist cathode exhaust gas, and a water separator for separating water from the cathode exhaust gas. Water separators are particularly frequently used in the anode subsystem to separate excess water from the anode exhaust gas and direct it into the environment of the fuel cell system via an anode purge line and an anode purge valve.

[0005] Despite the measures known in the state of the art, condensate can accumulate on valves and / or in duct structures in the area of ​​the water separator when a mobile fuel cell system is shut down. The accumulated water must be thawed or defrosted at ambient temperatures below freezing, which requires a relatively long time and requires a lot of heating to restore the valve function for subsequent operation of the fuel cell system and to reduce valve wear.

[0006] The object of the present invention is to provide means for a fast, component-friendly and / or efficient frost start in a fuel cell system.

[0007] The above object is achieved by the patent claims. In particular, the above object is achieved by the water separator according to claim 1, as well as by the fuel cell system and the vehicle according to the dependent claims. Further advantages of the disclosed technology emerge from the subclaims, the description, and the figures. Features described in connection with the water separator also apply in connection with the fuel cell system and the vehicle, and vice versa, so that with regard to the disclosure of the individual aspects, reference is and / or can always be made to each other.

[0008] According to a first aspect of the present technology, a water separator for a fuel cell system is proposed. The water separator comprises a housing with a housing volume defined within the housing, a gas inlet opening, a gas outlet opening, and a water outlet opening for discharging water from the housing volume. The water separator further comprises a valve arrangement with a valve seat and a valve body positioned in the housing volume. In an open state of the valve arrangement, the valve body is spaced from the valve seat. In a closed state, the valve body is positioned on the valve seat. The valve arrangement is adjustable between the open state and the closed state. This means that the valve arrangement can be selectively set, in particular by means of a suitable actuator, to the open state or the closed state.The water separator also features a bypass integrated into the valve body, with a bypass inlet through which water can flow into the bypass, and a bypass outlet through which water can flow out of the bypass and into the surrounding area of ​​the housing. When closed, the bypass is positioned such that water can only flow into the bypass inlet when a certain water level is reached in the housing volume.

[0009] The proposed bypass can therefore be understood as an overflow bypass. When the valve arrangement is closed, water that collects as condensate in the housing volume can initially no longer flow through the water outlet opening. Accordingly, no more condensed water flows from the housing volume of the water separator to a valve positioned downstream. This, in turn, means that little or no water can freeze at the valve downstream of the water separator. Finally, in the event of a frost start, the valve can be defrosted relatively quickly, with minimal component damage and in an energy-efficient manner. Defrosting can be carried out using a heating medium, for example in the form of an electric resistance heater. The heating medium can convert the frozen water at the valve back into a liquid state, making the valve ready for operation of the fuel cell system.The less ice that needs to be thawed, the faster and more energy-efficiently the fuel cell system can be started up. A downstream valve could, for example, be an anode purge valve in the anode purge line of a fuel cell system.

[0010] During a so-called blowdown and shutdown of a fuel cell system, the proposed water separator can thus form a kind of water trap in which condensing water collects without entering the channel connected to the housing, for example, the anode purge line between the housing and the anode purge valve. As the fuel cell system cools further, the condensed water can now freeze in a definable area above the specified height of the bypass inlet opening in the housing volume, without, for example, the anode purge line and / or the anode purge valve becoming blocked by large amounts of ice.

[0011] During a frost start, only a small amount of ice, if any, needs to be defrosted at the valve downstream of the water separator. Once the fuel cell system is in operation, a warm gas mixture and warm liquid water can be produced, which then comes into contact with the still frozen water in the housing volume. Initially, some more ice may form in a boundary layer between the new warm water and the old frozen water, and the ice layer may increase. However, the height of the bypass inlet opening can be selected so that even during the start-up phase of the fuel cell system, only liquid water can pass through the bypass towards the anode purge valve or the valve positioned downstream of the water separator. As soon as the old frozen water or the corresponding ice has completely thawed, the water separator valve arrangement can be reset to the open state.

[0012] In this case, water is usually understood to mean condensed liquid water. The valve seat can be configured as part of the water outlet opening and / or on the water outlet opening. This means that the valve seat can at least partially form the water outlet opening and / or the water outlet opening can at least partially form the valve seat. The housing can have a roof section in which the gas inlet opening and the gas outlet opening are configured. The housing can further have a base section in which the water outlet opening and / or the valve seat can be configured. The base section can have an inner base surface that defines part of the housing volume. The base surface can be straight, flat, or in one plane, apart from a region of the water outlet opening and / or the valve seat.

[0013] When the valve assembly is closed, the bypass inlet is positioned at a specific or predefined distance above the base surface. This means that when closed, the bypass inlet has a corresponding water inlet height above the base surface. The distance and / or the water inlet height can, for example, have a value in a range between 0.5 cm and 20 cm or between 1 cm and 10 cm. Water can only flow into the bypass inlet when the water level in the housing volume reaches the water inlet height of the bypass inlet. The water inlet height or the position of the bypass inlet can be set differently for different water separators for different applications. The water level can be understood as the fill level of water in the housing volume.The water level can also be understood as a water depth that the water must reach from a bottom surface of the bottom section in order to border the bypass inlet opening.

[0014] The bypass can have at least one bypass inlet opening at different locations in the valve body. The valve body can have a conical valve head, which can have a soft and / or elastic material in the region of a contact surface with the valve seat for a reliable sealing effect. Alternatively or additionally, the valve seat can have a soft and / or elastic material. The gas inlet opening can be configured to introduce a process gas into the housing volume. The gas outlet opening can be configured to guide the process gas out of the housing volume. The process gas can be understood to be a gas or a gas mixture that is guided from a fuel cell stack of the fuel cell system into the housing volume and / or that is guided through the housing volume towards the fuel cell stack and from which water and / or moisture is to be separated.

[0015] The fact that the valve body is positioned in the housing volume can be understood to mean that at least part of the valve body is positioned in the housing volume. Another part of the valve body can extend out of the housing volume and out of the housing of the water separator and can be connected there to a drive for moving the valve body. By moving the valve body, the valve arrangement can be set to the open state and the closed state. The fact that the bypass is integrated into the valve body can be understood to mean that the bypass can be designed as an integral part of the valve body. For example, the bypass can be designed in the form of at least one through-bore and / or through-opening through the valve body.

[0016] According to a further embodiment of the present technology, it is possible for the valve body to have a valve head and a valve stem adjoining the valve head, the bypass inlet opening being formed on the valve stem, and the bypass outlet opening being formed on the valve head. In this way, the valve body with the bypass integrated therein can be manufactured particularly easily. For example, a valve head with a first through-opening and / or through-bore and a valve stem with a second through-bore and / or through-opening can be manufactured, wherein the first through-opening and the second through-opening can form the bypass after the valve head has been fastened to the valve stem. The valve stem can be cylindrical. The valve head can be frusto-conical. The valve stem can be connected to the valve head in a form-fitting, force-fitting, and / or material-fitting manner.Furthermore, it is possible that the valve stem together with the valve head is at least partially manufactured in one piece, integrally and / or monolithically.

[0017] Furthermore, in a water separator according to the present technology, it is possible for the valve body to be movable in a valve body movement direction to adjust the open state and / or the closed state, and for an inlet opening direction of the bypass inlet opening to extend transversely to the valve body movement direction. Such a bypass is particularly easy to manufacture. For example, at least one bore can be introduced into the valve body transversely to a longitudinal direction of the valve body, wherein the longitudinal direction corresponds or can correspond to the valve body movement direction. The bypass inlet opening can extend not only transversely, but also orthogonally to the valve body movement direction and / or to the longitudinal direction of the valve body. The inlet opening direction can correspond to a normal vector of the bypass inlet opening.The bypass can extend straight, diagonally and / or curved through the valve body following the bypass inlet opening.

[0018] Furthermore, in the water separator disclosed here, it is possible for a through-opening with two opposing bypass inlet openings to be configured in the valve body. Such a bypass is particularly easy to manufacture and also easily leads to a relatively large overall opening cross-section of the bypass inlet opening. Accordingly, the bypass inlet opening in the present case does not refer to just a single bypass inlet opening. Rather, the bypass inlet opening can have several spaced-apart bypass inlet openings. The through-opening can be manufactured as a product of a cast component for the valve body or as a through-bore in the valve body. The bypass inlet openings can all extend transversely and / or orthogonally to the direction of movement of the valve body and / or to the longitudinal direction of the valve body.

[0019] In a further embodiment of the present technology, it is possible for a roof overhang to be formed on the valve body, which covers the bypass inlet opening. The roof overhang is a simple means of preventing unwanted condensation from entering the bypass. Condensation that forms on a valve stem of the valve body or on the valve body above the bypass inlet opening is reliably guided past the bypass inlet opening via the roof overhang. In addition, the roof overhang can serve as a stop for the valve body on an inner wall surface of the housing to prevent the valve body from slipping out of the housing and / or extending out of the housing beyond a maximum desired length when adjusted to the open state. For this purpose, the roof overhang can be designed in a ring shape on the valve body.The roof overhang can be designed as an integral and / or monolithic component of the valve body and in particular of a valve stem of the valve body. The roof overhang can be understood as a sudden increase in the diameter of the valve body in the region of the roof overhang. The diameter of the valve body can increase in the region of the roof overhang by at least 5%, by at least 20%, or by at least 50% compared to a diameter directly adjacent to the roof overhang.

[0020] If the roof overhang is positioned directly at the bypass inlet, unwanted ingress of condensed water into the bypass can be particularly reliably prevented. "The roof overhang is positioned directly at the bypass inlet" means that the roof overhang extends directly from an edge area of ​​the bypass inlet away from the valve body or the bypass inlet. The roof overhang can form part of the bypass inlet.

[0021] Furthermore, in a water separator according to the present technology, it is possible for the valve body to be movable in a valve body movement direction to adjust the open state and / or the closed state, and for an outlet opening direction of the bypass outlet opening to extend parallel to the valve head movement direction and / or along the valve head movement direction. With such a configuration, the water can be discharged particularly easily through the valve head, which can be positioned directly on the water outlet. Consequently, a particularly compact and robust design of the water separator can be achieved. The bypass can be configured coaxially to a rotation axis of the valve head in the region of the bypass outlet opening and / or towards the bypass outlet opening.

[0022] In a water separator disclosed here, the valve seat can be configured as a monolithic and / or integral component of the housing. This allows a particularly robust construction of the water separator to be achieved. Furthermore, the valve seat and / or the water outlet opening can be configured as an integral and / or monolithic component of the housing. The valve seat and / or the water outlet opening can be positioned coaxially or substantially coaxially to the housing volume. This means that the valve seat and / or the water outlet opening can be positioned centrally or substantially centrally in the base section.

[0023] In the water separator disclosed here, the valve assembly can have a plunger, and the valve body can have a valve head, wherein the plunger is mounted so as to be movable in a plunger movement direction and relative to the valve head for pressing the valve head onto the valve seat. This means that the plunger and the valve head can be provided as separately movable components. In this way, the manufacture of the valve assembly can be further simplified. The valve head can be positioned as a type of float in the housing volume. The valve head is configured such that, in the open state, it can float on condensed water that collects in the housing volume. Accordingly, the density of the valve head, at least in this embodiment, can be lower than the density of water.If the closed state is to be set, the plunger can be pressed onto the valve head, for example, onto a roof projection of the valve head as described above, until the valve head is pressed positively against the water outlet opening. Water can now only flow out of the housing volume via the bypass. The fact that the plunger is mounted so that it can move relative to the valve head means that the plunger and the valve head are positioned so that they can move independently of one another. In particular, the plunger can be moved without the valve head moving or having to move.

[0024] According to a further aspect of the present technology, a fuel cell system is proposed comprising a fuel cell with an anode and a cathode, an anode subsystem, a cathode subsystem, and a water separator as described in detail above. The water separator is configured to separate water from a process gas in the anode subsystem and / or the cathode subsystem. The fuel cell system thus offers the same advantages as those described in detail with reference to the water separator. The fuel cell system is preferably configured for mobile applications such as vehicles, in particular for providing energy for at least one drive machine such as an electric motor for propulsion of the vehicle. The fuel cell can be designed in the form of a fuel cell stack with multiple fuel cell elements.In its simplest form, a fuel cell is an electrochemical energy converter that converts fuel and oxidant into reaction products, producing electricity and heat. The anode and cathode, or multiple anodes and cathodes, can each be separated from each other by an ion-selective or ion-permeable separator. The fuel cell system can have multiple water separators as described above, which can be positioned at different locations in the cathode subsystem and / or the anode subsystem. The process gas can be understood as a gas or a gas mixture in the anode subsystem and / or the cathode subsystem.

[0025] In a fuel cell system disclosed herein, the anode subsystem can have an anode purge valve in an anode purge line, wherein the water separator can be positioned upstream of the anode purge valve to direct separated water from the process gas through the anode purge line to the anode purge valve. Tests conducted within the scope of the present development have shown that the above-described advantages are particularly effective in the area of ​​the water separator on the anode purge line. Nevertheless, the proposed water separator can also be positioned at other locations in the anode subsystem and / or the cathode subsystem.

[0026] A further aspect of the present technology relates to a vehicle having a fuel cell system as described above and at least one electric motor for driving the vehicle, wherein the fuel cell system is configured to supply power to the at least one electric motor. The vehicle thus also offers the advantages described above. The vehicle can be understood to mean a motor vehicle such as a motor-driven two-wheeler, a car, or a truck. The vehicle can also be understood to mean a road vehicle, an aircraft, a watercraft, a rail vehicle, a spacecraft, or a robot. The vehicle can also be understood to mean a purely electric vehicle or a hybrid electric vehicle, which, in addition to the at least one electric motor, has an internal combustion engine for driving the vehicle.

[0027] Further measures will become apparent from the following description of various exemplary embodiments, which are schematically illustrated in the figures. All features and / or advantages arising from the claims, the description, or the figures, including structural details and spatial arrangements, may be significant both individually and in various combinations.

[0028] They show schematically:

[0029] Fig. 1 shows a water separator according to a first embodiment in a first operating state,

[0030] Fig. 2 shows the water separator of the first embodiment in a second operating state,

[0031] Fig. 3 the water separator of the first embodiment in a third operating state,

[0032] Fig. 4 shows the water separator of the first embodiment in a fourth operating state,

[0033] Fig. 5 shows the water separator of the first embodiment in a fifth operating state,

[0034] Fig. 6 shows a water separator according to a second embodiment in a first operating state,

[0035] Fig. 7 shows a fuel cell system with a water separator according to a first embodiment,

[0036] Fig. 8 shows a fuel cell system with a water separator according to a second embodiment,

[0037] Fig. 9 shows a vehicle with a fuel cell system according to one embodiment. Elements with the same function and mode of operation are provided with the same reference numerals in the figures. In particular, in Figures 2 to 5, individual reference numerals have been partially omitted for clarity.

[0038] Fig. 1 shows a water separator 11 according to a first embodiment for a fuel cell system 10 shown in Fig. 7. The illustrated water separator 11 comprises a housing 12 with a housing volume 19 defined within the housing 12, a gas inlet opening 13, a gas outlet opening 15, and a water outlet opening 17. Water 18 can be discharged from the housing volume 19 through the water outlet opening 17. The water outlet opening 17 is located in a bottom portion 26 of the housing 12. The bottom portion 26 has a bottom surface 20 that forms part of an inner wall surface 27 of the housing 12.

[0039] The water separator 11 shown has a valve arrangement with a valve seat 22 and a valve body 21 positioned in the housing volume 19. The valve seat 22 is designed as part of the water outlet opening 17. The valve seat 22 is also designed as an integral component of the housing 12 and in particular of the water outlet opening 17. The valve arrangement shown is in an open state S1, in which the valve body 21 is spaced from the valve seat 22. The valve body can also be set to a closed state S2, in which the valve body 21 is positioned on the valve seat 22. Such a state is shown in Figures 2 to 4. To set or adjust the valve arrangement to the desired states, the valve body 21 can be designed to be mechanically and / or electromagnetically controllable.

[0040] The valve body 21 has an integrated bypass 23. The bypass 23 has a bypass inlet opening 24 through which water 18 can flow into the bypass 23. The bypass 23 also has a bypass outlet opening 25 through which water 18 can flow out of the bypass 23 and, in the closed state S2, into the surroundings of the housing 12. The valve body 21 has a valve head 28 and a valve stem 29 adjoining the valve head 28. The bypass inlet opening 24 is formed on the valve stem 29. The bypass outlet opening 25 is formed on the valve head 28.

[0041] As can be seen from Fig. 1, the valve body 21 is used to adjust the open

[0042] State S1 and / or the closed state S2 in a valve body

[0043] Movable in a direction of movement D1, wherein an inlet opening direction D2 of the bypass inlet opening 24 extends orthogonally to the valve body direction of movement D1. More precisely, a through-bore with two opposing bypass inlet openings 24 is formed in the valve body 21. Furthermore, a roof projection 31 is formed on the valve body 21, which roofs the bypass inlet opening 24. The roof projection 31 is formed directly on the bypass inlet opening 24. As further shown in Fig. 1, the valve body 21 is movable in a valve body direction of movement D1 to set the open state S1 and / or the closed state S2, wherein an outlet opening direction D3 of the bypass outlet opening 25 extends along the valve head direction of movement D1 or in the same direction. The water separator 11 shown in Fig. 1 has a heating means 33 in the form of an electrical resistance heater.The heating medium 33 can heat the anode purge valve 51 during a frost start until there is no more ice on the anode purge valve 51 and / or until the anode purge valve 51 is functional again. The heating medium 33 can be understood as an optional functional component that can, but does not have to, be activated during a frost start.

[0044] Downstream of the gas outlet opening 15, a gas purge valve 34 is positioned in a branch path. The branch path 59 branches off from a recirculation path 58. Furthermore, a heating means 33 for heating the anode purge valve 51 is positioned on the anode purge valve 51. The heating means 33 shown as an example is configured as an electric heating means.

[0045] With reference to Figures 1 to 4, the operation of the illustrated water separator 11 will be explained below for a situation in which the ambient temperature is below freezing and frost or ice formation in the water separator 11 and at the anode purge valve 51 is therefore to be expected. Within the scope of such frost preconditioning of the system, the water separator 11, as shown in Fig. 1, initially fulfills its main function by separating water 18 from the process gas 14. The separated water 18 collects in the base section 26 or on the base surface 20 and flows from there through the water outlet opening 17 into the anode purge line 52 shown as an example. In the anode purge line 52, the water 18 flows through an open anode purge valve 51.

[0046] If the purging process is to be terminated as part of the frost preconditioning of the system, the valve arrangement is set to the closed state S2, which is shown in Fig. 2. For this purpose, after as much liquid water 18 as possible has been discharged from the housing volume 19, the valve body 21 is pressed onto the valve seat 22 and an optionally present gas purge valve 34 is kept closed. The process gas 14 can now flow not only out of the gas outlet opening 15, but also through the bypass 23 and through the still open anode purge valve 51. The portion of the process gas 14 that flows through the bypass 23 through the anode purge valve 51 is largely freed of water by separation and can thus blow any possible water deposits out of the anode purge valve 51 into the anode purge line 52 before the anode purge valve 51 is closed and the fuel cell system 10 is shut down. As shown in Fig.2, the bypass 23 is positioned in the closed state S2 such that water 18 can only flow into the bypass inlet opening 24 when a certain water level in the housing volume 19 is reached and only then can it flow out of the housing volume 19 through the bypass 23.

[0047] In Fig. 3, after the fuel cell system 10 has been shut down and cooled down, water 18 condensing from the remaining process gas 14 collects in the housing volume 19 below the bypass inlet opening 24 and thus remains in the housing volume 19 or is not directed toward the anode purge valve 51. Only a small amount of water 18 collects at the now closed anode purge valve 51.

[0048] Once the temperature in the vicinity of the water separator 11 falls below freezing, the water 18 can freeze or turn into ice 18', as shown in Fig. 4. Ice 18' also forms at the anode purge valve 51.

[0049] A defrosting process is then described with reference to Fig. 5. To restart the fuel cell system 10, the anode purge valve 51 is first freed of ice 18'. In a variant with an optional gas purge valve 34 and with its downstream connection to the anode purge line 52 downstream of the anode purge valve 51, the start-up operation can be carried out in the example shown even before the anode purge valve 51 is free of ice. Thus, the start-up operation can be initiated by passing process gas 14 through the anode purge line 52 even before the anode purge valve 51 is free of ice, since the gas purge function can be performed in the anode purge line 52 through the gas purge valve 34.The newly generated process gas 14 during operation, which flows through the gas inlet opening 13 into the housing volume 19, and in particular the warm water 18 separated by the water separator 11, can reach the anode purge valve 51 through the bypass 23 and accelerate the defrosting process there. Afterwards or during this time, the ice 18' on the anode purge valve 51 can be thawed using the heating medium 33 in order to restore the function of the anode purge valve 51 more quickly. General system operation can now be enabled, and the fuel cell system 10 can be operated accordingly. The bypass 23 shown is designed such that the newly generated warm water quantity 18 energetically exceeds the existing ice quantity 18'. The newly generated warm water 18 orLiquid water that collects again in the housing volume 19 during start-up of the fuel cell system 10 can now not only thaw the ice 18' formed there, but can also flow through the bypass 23 to the anode purge valve 51 and counteract ice regeneration there as well, so that the heater 33 can be turned down or switched off relatively quickly. In a variant of such a system without an optional gas purge valve 34 and without its downstream connection to the anode purge line 52 downstream of the anode purge valve 51, the heater 33 can heat the anode purge valve 51 at least until the resulting defrosting reliably enables the anode purge valve 51 to function. This allows the system to be enabled for start-up, and the heater 33 only needs to be operated in a supporting capacity as long as there is a risk of possible ice regeneration.The anode purge valve 51, which is ultimately ice-free in both variants, ensures the purge function even if residual ice 18' is still present in the housing volume 19. Once the valve body 21 is completely free of ice 18', the valve arrangement can be reset to the open state S1 shown in Fig. 1.

[0050] Fig. 6 shows a water separator 11 according to a second embodiment. In the embodiment shown in Fig. 6, the valve arrangement has a plunger 32. The plunger 32 is mounted so as to be movable in a plunger movement direction D4 and relative to the valve head 28 in order to be able to press the valve head 28 onto the valve seat 22. The valve head 28, including the integrated bypass 23 and the roof projection 31, is configured as a type of float with a lower density than the water 18. This means that if the plunger 32 does not press onto the valve head 28 or onto the roof projection 31, the valve head 28 floats on water 18 that collects in the housing volume 19 and in this way allows the water 18 to flow unhindered through the water outlet opening 17.The valve head 28, designed as a float, can be guided by a guide of the water separator 11, so that uncontrolled movement and / or floating of the valve head 28 away from a position above the water outlet opening 17 or near the valve seat 22 can be prevented. In other words, the valve head 28 can be guided by means of the guide for movement in the plunger movement direction D4 or in a corresponding valve body movement direction D1.

[0051] Fig. 7 shows a fuel cell system 10 comprising a fuel cell 40 with an anode 41 and a cathode 42, an anode subsystem 50, a cathode subsystem 60, and a water separator 11 as described above. In the example shown, the water separator 11 is configured to separate water 18 from a process gas 14 in the form of an anode exhaust gas in the anode subsystem 50. The illustrated anode subsystem 50 has an anode inlet path 56, an anode exhaust gas path 57, an anode purge line 52, a recirculation path 58, and a branch path 59 branching off from the recirculation path 58. The branch path 59 branches into the anode purge line 52 downstream of an anode purge valve 51 positioned in the anode purge line 52 downstream of the water separator 11. The gas purge valve 34 is positioned in the branch path 59 to effect the purging of the water separator 11 described in detail above.An inlet valve 53 is positioned in the anode inlet path 56 for controlled admission of anode gas into the anode inlet path 56.

[0052] Downstream of the inlet valve 53, an injector / ejector 54 is positioned, via which the anode gas can be conveyed to the anode 41.

[0053] Fig. 8 shows a fuel cell system 10 according to a second embodiment, in which, in particular, the cathode subsystem 60 is shown in further detail (but still greatly simplified). The cathode subsystem 60 shown includes a compressor 61, a charge air cooler

[0054] 62 and a portion of a humidifier 63 are positioned in a cathode inlet path 67. A water separator 11, another portion of the humidifier 63, and a turbine 64 are positioned in a cathode exhaust path 68. The water separator 11 is positioned in the cathode exhaust path 68 downstream of the cathode 42 and upstream of the humidifier 63. Water can be passed via the water separator 11 through a bypass line 66 and a control valve 65 past the humidifier 63 and past the turbine 64. Alternatively or additionally, a water separator 11 as described above can be positioned in the cathode exhaust path 68 downstream of the humidifier 63. Alternatively or additionally, a water separator 11 as described above may be positioned in the cathode inlet path 67, for example downstream of the humidifier 63 and upstream of the cathode 42.Upstream of the humidifier 63, a first shutoff valve 69 is positioned in the cathode inlet path 67, through which a cathode gas flow toward the cathode 42 can be controlled and blocked. Downstream of the humidifier.

[0055] 63, a second shut-off valve 69 is positioned in the cathode exhaust gas path 68, through which a cathode gas flow from the cathode 42 in the direction of the humidifier 63 can be controlled and blocked.

[0056] Fig. 9 shows a vehicle 100 in the form of a road vehicle with a fuel cell system 10 as described above. The vehicle 100 has two electric motors 90 for driving the vehicle 100, with the fuel cell system 10 configured to supply power to the electric motors 90. The vehicle 100 also has a fuel tank 80 for supplying fuel to the fuel cell system 10. The technology disclosed here allows for further design principles in addition to the embodiments illustrated. This means that the technology should not be considered limited to the exemplary embodiments explained with reference to the figures.

[0057] List of reference symbols

[0058] Fuel cell system water separator housing

[0059] Gas inlet Process gas Gas outlet Water outlet Water ' Ice

[0060] Housing volume

[0061] Bottom surface valve body valve seat

[0062] bypass

[0063] Bypass inlet Bypass outlet Bottom section

[0064] Inner wall surface Valve head Valve stem Roof overhang Stamp

[0065] Heating medium

[0066] Gas purge valve fuel cell

[0067] anode

[0068] cathode

[0069] Anode subsystem Anode purge valve Anode purge line Inlet valve

[0070] Ejector Anode inlet path Anode exhaust path 8 Recirculation path 9 Branch path 0 Cathode subsystem 1 Compressor 2 Charge air cooler 3 Humidifier 4 Turbine 5 Control valve 6 Bypass line 7 Cathode inlet path

[0071] 68 Cathode exhaust path

[0072] 69 check valve

[0073] 80 fuel tank

[0074] 90 electric motor

[0075] 100 vehicles

[0076] D1 Valve body movement direction

[0077] D2 Inlet opening direction

[0078] D3 Outlet opening direction

[0079] D4 Punch movement direction

Claims

Patent claims 1. Water separator (11) for a fuel cell system (10), comprising: - a housing (12) with a housing volume (19) defined within the housing (12), a gas inlet opening (13), a gas outlet opening (15) and a water outlet opening (17) for discharging water (18) from the housing volume (19), - a valve arrangement with a valve seat (22) and a valve body (21) positioned in the housing volume (19), wherein the valve arrangement can be set into an open state (S1), in which the valve body (21) is spaced from the valve seat (22), and into a closed state (S2), in which the valve body (21) is positioned on the valve seat (22), and - a bypass (23) integrated into the valve body (21) with a bypass inlet opening (24) through which water (18) can flow into the bypass (23), and a bypass outlet opening (25) through which water (18) can flow out of the bypass (23) and into the surroundings of the housing (12), - wherein the bypass (23) is positioned in the closed state (S2) such that water (18) can only flow into the bypass inlet opening (24) when a certain water level in the housing volume (19) is reached.

2. Water separator (11) according to claim 1, wherein the valve body (21) has a valve head (28) and a valve stem (29) adjoining the valve head (28), the bypass inlet opening (24) is formed on the valve stem (29) and the bypass outlet opening (25) is formed on the valve head (28).

3. Water separator (11) according to one of the preceding claims, wherein the valve body (21) is movable in a valve body movement direction (D1) for setting the open state (S1) and / or the closed state (S2) and an inlet opening direction (D2) of the bypass inlet opening (24) extends transversely to the valve body movement direction (D1).

4. Water separator (11) according to one of the preceding claims, wherein a through opening with two opposite bypass inlet openings (24) is formed in the valve body (21).

5. Water separator (11) according to one of the preceding claims, wherein a roof projection (31) is formed on the valve body (21) which covers the bypass inlet opening (24).

6. Water separator (11) according to claim 5, wherein the roof projection (31) is formed directly on the bypass inlet opening (24).

7. Water separator (11) according to one of the preceding claims, wherein the valve body (21) is movable in a valve body movement direction (D1) for setting the open state (S1) and / or the closed state (S2) and an outlet opening direction (D3) of the bypass outlet opening (25) extends parallel to the valve head movement direction (D1) and / or along the valve head movement direction (D1).

8. Water separator (11) according to one of the preceding claims, wherein the valve seat (22) is designed as a monolithic and / or integral component of the housing (12).

9. Water separator (11) according to one of the preceding claims, wherein the valve arrangement has a plunger (32) and the valve body (21) has a valve head (28), wherein the plunger (32) is mounted so as to be movable in a plunger movement direction (D4) and relative to the valve head (28) for pressing the valve head (28) onto the valve seat (22).

10. A fuel cell system (10) comprising a fuel cell (40) with an anode (41) and a cathode (42), an anode subsystem (50), a cathode subsystem (60) and a water separator (11) according to one of the preceding claims, wherein the water separator (11) is configured to separate water (18) from a process gas (14) in the anode subsystem (50) and / or in the cathode subsystem (60).

11. The fuel cell system (10) of claim 10, wherein the anode subsystem (50) includes an anode purge valve (51) in an anode purge line (52), and the water separator (11) is positioned upstream of the anode purge valve (51) to direct separated water (18) from the process gas (14) through the anode purge line (52) to the anode purge valve (51).

12. Vehicle (100) with a fuel cell system (10) according to one of claims 10 to 11 and at least one electric motor (90) for driving the vehicle (100), wherein the fuel cell system (10) is configured to supply power to the at least one electric motor (90).

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