Fuel cell system and vehicle having fuel cell system

Abstract

The present invention relates to a fuel cell system (10) comprising: a fuel cell (11) having an anode (12) and a cathode (13); a cathode inlet path (14) for conducting cathode gas into the cathode (13); a cathode exhaust gas path (15) for conducting cathode exhaust gas from the cathode (13) into the surroundings of the fuel cell system (10); a coolant cooler (24); a main coolant line (25) for conducting coolant from the coolant cooler (24) to the fuel cell (11) and for conducting coolant from the fuel cell (11) to the coolant cooler (24); a temperature control unit (40) having a heat exchange portion (41), the heat exchange portion (41) being designed as part of the cathode exhaust gas path (15); a secondary coolant line (23) for conducting the coolant from the coolant cooler (24) into the temperature control unit (40) for the purpose of heat transfer from the coolant to cathode exhaust gas in the heat exchange portion (41); and a moisture path (42) for conducting a water-containing fluid (43) into the heat exchange portion (41). The invention also relates to a vehicle (100) having the fuel cell system (10).

Description

[0001] Description

[0002] Fuel cell system and vehicle with fuel cell system

[0003] The technology disclosed here relates to a fuel cell system comprising a fuel cell, a cathode inlet path for conducting cathode gas into the cathode of the fuel cell, a cathode exhaust path for conducting cathode exhaust gas from the cathode into the environment of the fuel cell system, a coolant cooler, a coolant main line for conducting coolant from the coolant cooler to the fuel cell and for conducting coolant from the fuel cell to the coolant cooler, and a temperature control unit for controlling the temperature of the fuel cell system using the coolant. The technology further relates to a vehicle having such a fuel cell system.

[0004] Fuel cell systems for mobile applications are known in the art. In a vehicle, the fuel cell system is configured, in particular, to provide electrical energy to a drive motor for propulsion of the vehicle.

[0005] Generic fuel cell systems comprise a fuel cell stack. The fuel cell stack typically comprises several fuel cells, each with two electrodes and a membrane arrangement between the two electrodes. Within the fuel cell stack, fuel can react with oxygen in a reverse electrolysis process, generating electricity. The fuel can be supplied to the fuel cell stack from one or more pressure vessels in the vehicle. The oxygen is typically taken from the ambient air.

[0006] Various approaches are known for thermal management of fuel cell systems. For example, it is known for a fuel cell system to have a cooler with a coolant line through which coolant can be conducted to cool the fuel cell stack. Furthermore, it is known for the coolant to be branched off from the coolant line in order to cool other functional components and / or areas in the fuel cell system via heat exchangers, or to enable heat exchange between the heated coolant and other functional components of the fuel cell system. The object of the present invention is to provide improved temperature management in a fuel cell system and in a vehicle with a fuel cell system.

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

[0008] According to a first aspect of the present technology, a fuel cell system is proposed, comprising:

[0009] - a fuel cell with an anode and a cathode,

[0010] - a cathode inlet path for directing cathode gas into the cathode,

[0011] - a cathode exhaust path for conducting cathode exhaust from the cathode into the environment of the fuel cell system,

[0012] - a coolant cooler,

[0013] - a coolant main line for conducting coolant from the coolant cooler to the fuel cell and for conducting coolant from the fuel cell to the coolant cooler,

[0014] - a temperature control unit with a heat exchange section, wherein the heat exchange section is designed as part of the cathode exhaust gas path,

[0015] - a coolant bypass line for conducting the coolant from the coolant cooler into the temperature control unit for heat transfer from the coolant to cathode exhaust gas in the heat exchange section and

[0016] - a moisture path for conducting a water-containing fluid into the heat exchange section.

[0017] Within the scope of the present technology, the basic principle of a heat pipe arrangement was initially transferred to the described fuel cell system by allowing the cathode exhaust path, or a portion of the cathode exhaust path, to serve as a heat exchange section, and by arranging the temperature control unit at the heat exchange section. The fuel cell system was subsequently further developed so that the water-containing fluid can be directed into the heat exchange section via the moisture path, thereby promoting or enhancing the desired heat exchange there. This means that the cathode exhaust path can not only be used as a cooling surface, but can also achieve particularly effective and / or efficient cooling through evaporative cooling.The coolant, which is heated by the fuel cell and fed into the temperature control unit via the coolant bypass line, can be cooled in the temperature control unit by transferring heat from the heated coolant to the cooler cathode exhaust gas. This enables reliable cooling of the fuel cell system over extended periods, even during high-load operation of the fuel cell system. Previously necessary primary cooling surfaces and / or heat sinks can be reduced in size or even eliminated entirely. During high-load operation, thermal requirements can be met that would previously have been impossible, or at least not possible during certain load peaks. High load points over extended periods occur, for example, during extended uphill journeys by the vehicle and / or when the vehicle is towing a trailer.The temperature control unit and the heat exchange section can be considered as components of a heat exchanger, whereby the temperature control unit can be understood as a hot side of the heat exchanger and the heat exchange section can be understood as a cold side of the heat exchanger.

[0018] In the proposed fuel cell system, only, or at least predominantly, components that are already exposed to such media contact come into contact with the water-containing fluid. Compared to a fuel cell system in which, for example, a radiator assembly in the front of the vehicle is sprayed with water, the proposed solution is therefore particularly gentle on components. For example, unwanted corrosion can be avoided.

[0019] The coolant cooler can be understood as a temperature control unit that can be configured not only for cooling, but also for warming and / or heating components of the fuel cell system. The water-containing fluid can be understood as water, water vapor, and / or a water mist. For example, the moisture path can be configured to conduct water to the heat exchange section and to spray the water at the heat exchange section, for example as a water mist, into the heat exchange section or into the corresponding section of the cathode exhaust gas path. Conducting the coolant into the moisture path can be understood as conducting the coolant directly into the moisture path and / or directly into a flow volume defined by the moisture path.The aqueous fluid can be deionized water, plain water, and / or condensed water, which can be sprayed into the heat exchange section, for example, as a water mist. Additives such as surfactants, alcohols, solvents, oils, diluents, and / or glycols can be mixed into the aqueous fluid. In this way, the evaporation properties of the aqueous fluid can be improved. Surfactants can reduce the surface tension of the aqueous fluid. This facilitates evaporation by promoting the formation of thin layers that can evaporate more quickly. Alcohols such as ethanol, methanol, or isopropanol evaporate quickly and can therefore accelerate the evaporation process. Alcohols can, for example, lower the boiling point of the aqueous fluid. The fuel cell system can have a dosing device that mixes the additives into the aqueous fluid.The dosing device may be configured to introduce and / or inject the additives into the moisture path, for example at the temperature control unit and / or directly upstream of the temperature control unit.

[0020] The coolant can be understood, in particular, as a liquid coolant. The coolant main line can be understood as a coolant circuit through which the coolant can circulate, in particular, between the coolant cooler and the fuel cell. The coolant secondary line can be understood as a coolant circuit through which coolant can circulate, in particular, between the coolant main line and the temperature control unit. For controlled circulation of the coolant in the coolant main line and / or in the coolant secondary line, suitable valves can be configured in the coolant main line and / or in the coolant secondary line.

[0021] The fuel cell system is preferably configured for mobile applications such as vehicles, in particular for providing electrical energy for at least one drive machine such as an electric motor for propulsion of the vehicle. The term fuel cell can be understood to mean at least one fuel cell. Accordingly, the term fuel cell can be understood to mean a single fuel cell and in particular a fuel cell stack with multiple fuel cells. In its simplest form, the fuel cell is an electrochemical energy converter that converts fuel and oxidant into reaction products, thereby generating electricity, water, and heat. The anode and cathode can each be separated from one another by an ion-selective or ion-permeable separator. In a fuel cell stack, the anode can be understood to mean an anode region and the cathode can be understood to mean a cathode region.According to a further embodiment of the technology described here, the fuel cell system can have a reservoir for storing the water-containing fluid, wherein the moisture path is configured to conduct water-containing fluid from the reservoir into the heat exchange section. In this way, the water-containing fluid can be reliably made available for the desired purpose. The reservoir can be understood as a standalone reservoir, for example in the form of a tank. The reservoir can also be understood as an intermediate reservoir in which water-containing fluid generated in the fuel cell system can be temporarily stored. The reservoir can have a storage volume of, for example, more than 0.1 liter, more than 0.5 liter, or more than 1 liter. The reservoir can be understood as a moisture source and / or water source.

[0022] Furthermore, it is possible for the heat exchange section of the fuel cell system described here to define a flow volume through which the cathode exhaust gas flows, with at least a portion of the moisture path extending through the flow volume. This means that the moisture path can extend not only to the flow volume in order to introduce the water-containing fluid there, but also into the flow volume, beyond the flow volume, and / or at least partially through the flow volume. In this way, the water-containing fluid can be introduced into the flow volume particularly effectively and / or efficiently, leading to a correspondingly effective heat exchange. The moisture path described here can have a channel structure, in particular a tubular channel structure, which extends into the flow volume and / or at least partially through the flow volume.The moisture path and / or the channel structure can extend into the cathode exhaust path or into the flow volume defined therein at a position directly upstream of the heat exchange section. The moisture path and / or the channel structure can further extend into the cathode exhaust path or into the flow volume defined therein at a position downstream of the cathode and / or downstream of a turbine of the cathode exhaust path. The moisture path can extend at least partially parallel and / or coaxial with the heat exchange section in the flow volume.

[0023] In the fuel cell system described here, the moisture path can have at least one lateral opening in the region of the flow volume, which opening is configured to conduct the water-containing fluid from the moisture path into the flow volume. In this way, the water-containing fluid can be introduced into the flow volume in a simple and particularly effective manner. From the at least one lateral opening, the water-containing fluid can be introduced into the flow volume transversely to a flow direction of the cathode exhaust gas in the flow volume. The water-containing fluid can be injected, sprayed, and / or evaporated into the flow volume through the at least one lateral opening. The at least one lateral opening can be part of a correspondingly positioned injector, which can be configured in and / or on the moisture path.The at least one opening can be configured as a nozzle and / or a suction jet nozzle, which automatically draws in the water-containing fluid through the volume flow of the cathode gas. The at least one opening can be configured as a gap and / or an annular gap. The at least one lateral opening can extend in a radial direction through a wall of the moisture path. The moisture path can have a plurality of lateral openings or corresponding modifications that extend across the moisture path in a longitudinal direction and / or a circumferential direction of the moisture path.

[0024] In the fuel cell system described here, it is possible to configure a blocking means in the moisture path downstream of the reservoir to prevent and enable fluid flow from the reservoir into the temperature control unit. The blocking means allows the amount of water-containing fluid to be introduced into the flow volume to be easily and reliably controlled. The cooling function and / or cooling effect in the heat exchange section can be adjusted accordingly easily and reliably. The blocking means can be configured as a shut-off component, shut-off valve, or proportional valve, or can comprise a corresponding valve.

[0025] Furthermore, a fuel cell system as described above can have an air duct for guiding air along the temperature control unit, wherein the moisture path can be configured to guide the water-containing fluid into the air duct. The air duct can be understood as a fluid guidance structure that can be designed in a jacket-like and / or envelope-like manner around the temperature control unit. The desired cooling effect can be easily enhanced by means of the air duct. In the proposed embodiment, the temperature control unit can extend in a jacket-like, annular and / or tubular manner around the heat exchange section, wherein the air duct extends in a jacket-like, annular and / or tubular manner around the temperature control unit. The air duct can be understood as a guide and / or line for conducting air and / or another gas, in particular an oxygen-containing gas.

[0026] According to a further embodiment of the described technology, it is possible for the air duct to be configured to introduce ambient air from the environment of the fuel cell system into the air duct. This makes the air duct particularly simple and efficient. Ambient air can be understood as ambient air from the environment of the vehicle, for example, air from airstreams. Ambient air can also be understood as exhaust air from a fan of the vehicle and / or the fuel cell system, which can be channeled into the air duct via a fan duct.

[0027] Furthermore, it is possible for the fuel cell system described here to have a connecting section for introducing the air and / or the water-containing fluid from the air duct into the cathode exhaust path downstream of the heat exchange section. This allows the air duct to be integrated into the fuel cell system in a particularly compact manner. Furthermore, the air and / or the water-containing fluid can be guided over the entire outer wall of the temperature control unit, if possible. A separate gas outlet can be omitted. The connecting section can be configured such that the air and / or the water-containing fluid can be introduced into the cathode exhaust path directly downstream of the heat exchange section.Furthermore, it is possible for the connecting section to be configured such that, at least under certain operating conditions, the flow volume in the moisture path creates a suction jet effect on the air, the ambient air, and / or the water-containing fluid. In this way, the desired flow through the air duct can be achieved particularly easily and efficiently.

[0028] The fuel cell system described here can also have a water separator for separating water from process gas and / or from a process fluid of the fuel cell system, wherein the moisture path is configured to conduct water from the water separator into the reservoir. This allows the water-containing fluid to be made available for the desired purpose particularly easily and efficiently. Regular, manual replacement of a reservoir and / or manual refilling of the reservoir can be dispensed with in this case. Condensed product water from the fuel cell system can be specifically collected in the water separator and subsequently or during the process fed to the reservoir. The reservoir can be positioned directly downstream of the water separator and be directly fluidically connected to the water separator. In this case, the reservoir can be positioned in a bypass to the cathode exhaust gas path.

[0029] Furthermore, in a fuel cell system according to the technology described here, it is possible for an additional blocking means to be configured in the moisture path upstream of the reservoir to prevent backflow of the water-containing fluid from the reservoir. This can easily increase the operational reliability of the fuel cell system. The additional blocking means can, on the one hand, automatically fill the reservoir. On the other hand, a potentially damaging backflow of water or water-containing fluid can be prevented. The additional blocking means can be configured as a check valve or have a check valve. Using the blocking means, it is possible for the reservoir to be easily replaced and / or filled, for example, during vehicle service.This means that sensitive components of the fuel cell system can always be reliably protected from potentially contaminated water from the storage tank.

[0030] The heat exchange section of the fuel cell system described here can have an inner wall section, define a flow volume, and have projections that protrude from the inner wall section into the flow volume in a rib-like manner. The rib structure not only leads to effective heat transport from the coolant to the cathode exhaust gas, but can also be implemented relatively easily. For example, such a heat exchange section can be manufactured as an extruded profile. In this case, the projections can be designed as a monolithic component of the inner wall section. The projections can therefore be understood as an integral component of the inner wall section. In other words, the projections can form part of the inner wall section. Rib-like projections can be understood as projections that extend in a web-like, wall-like, and / or baffle-like manner in a longitudinal direction of the heat exchange section.The projections can be straight, curved, zigzag and / or wavy.

[0031] Furthermore, in a fuel cell system as described here, it is possible for the heat exchange section to define a flow volume, wherein an open-pore foam structure is configured in the flow volume. This also allows the desired heat transport to be achieved particularly effectively. The foam structure can be configured as an open-pore metal foam structure. The foam structure can be configured on a finished inner wall section of the heat exchange section and / or configured during the manufacturing process of the heat exchange section. The foam structure can therefore be configured in an annular and / or tubular manner on the inner wall section. Furthermore, it is possible to form an annular foam structure which has an inner open-pore structure and an outer closed wall. Accordingly, the foam structure can be configured as an integral component of the heat exchange section and / or the corresponding cathode exhaust gas path.Furthermore, it is possible for the foam structure to be configured in a projection-like and / or rib-like manner on the inner wall section. This means that the foam structure does not have to form a closed ring, but can, for example, be configured in a track structure on the inner wall section. In this way, the desired effects regarding heat exchange between the coolant and the cathode exhaust gas, as well as regarding impaired flow behavior in the cathode exhaust gas path, can be advantageously adjusted.

[0032] Furthermore, it is possible for the heat exchange section to contain boron nitride or to consist at least partially of boron nitride. Within the scope of the present development, it was initially recognized that boron nitride is actually suitable for use in the exhaust gas area of ​​the fuel cell system. By using boron nitride, particularly effective heat transfer from the coolant to the cathode exhaust gas can be achieved. Furthermore, the use of boron nitride can achieve particularly high stability in the cathode exhaust gas path. The boron nitride can be used as a filler in the heat exchange section. This means that the heat exchange section can be made of a material, for example plastic and / or metal, in which boron nitride is present as a filler.

[0033] A further aspect of the proposed 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 offers the same advantages as have been described in detail with reference to the fuel cell system. The term "vehicle" can be understood to mean a motor vehicle such as a motor-driven two-wheeler, a passenger car, and a truck. The term "vehicle" can also be understood to mean a road vehicle, an aircraft, a watercraft, a rail vehicle, a spacecraft, and a robot. The term "vehicle" can also be understood to mean a purely electric vehicle and a hybrid electric vehicle, which, in addition to the at least one electric motor, has an internal combustion engine for driving the vehicle.The vehicle can be understood as a so-called FCEV (Fuel Cell Electric Vehicle).

[0034] 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.

[0035] They show schematically:

[0036] Fig. 1 shows a fuel cell system according to a first embodiment of the present technology,

[0037] Fig. 2 is a sectional view of a temperature control unit according to the first embodiment of the present technology,

[0038] Fig. 3 shows a fuel cell system according to a second embodiment of the present technology,

[0039] Fig. 4 shows a fuel cell system according to a third embodiment of the present technology,

[0040] Fig. 5 shows a fuel cell system according to a fourth embodiment of the present technology,

[0041] Fig. 6 is a sectional view of a temperature control unit according to the fourth embodiment of the present technology,

[0042] Fig. 7 shows a fuel cell system according to a fifth embodiment of the present technology,

[0043] Fig. 8 is a sectional view of a temperature control unit according to the fifth embodiment of the present technology, Fig. 9 is a fuel cell system according to a sixth embodiment of the present technology,

[0044] Fig. 10 is a sectional view of a temperature control unit according to the sixth embodiment of the present technology and

[0045] Fig. 11 shows a vehicle with a fuel cell system according to an embodiment of the present technology.

[0046] Elements with the same function and mode of operation are provided with the same reference symbols in the figures.

[0047] Fig. 1 shows a fuel cell system 10 according to a first embodiment. The illustrated fuel cell system 10 comprises a fuel cell 11 in the form of a fuel cell stack with an anode 12 and a cathode 13. The fuel cell system 10 further comprises a cathode inlet path 14 for conducting cathode gas in the form of air into the cathode 13 and a cathode exhaust path 15 for conducting cathode exhaust gas from the cathode 13 into the environment of the fuel cell system 10. A compressor 17, a charge air cooler 18, and a humidifier 19 are positioned in the cathode inlet path 14. The humidifier 19, a water separator 49, and a turbine 16 are positioned in the cathode exhaust path 15. The fuel cell system 10 shown also includes a coolant cooler 24 and a coolant main line 25 for conducting coolant from the coolant cooler 24 to the fuel cell 11 and for conducting coolant from the fuel cell 11 to the coolant cooler 24.A coolant pump 26 is positioned in the main coolant line 25.

[0048] Furthermore, the fuel cell system 10 has a temperature control unit 40 with a heat exchange section 41, wherein the heat exchange section 41 is configured as part of the cathode exhaust gas path 15. The fuel cell system 10 further has a coolant bypass line 23 for conducting the coolant from the coolant cooler 24 into the temperature control unit 40 to enable heat transfer from the coolant to the cathode exhaust gas in the heat exchange section 41. Furthermore, the fuel cell system 10 has a humidity path 42 for conducting a water-containing fluid 43 into the heat exchange section 41. A reservoir 44 is positioned in the humidity path 42. A humidifier pump 20 is installed in the humidity path 42 to convey the water-containing fluid 43 via the humidity path 42 into the heat exchange section 41.The humidifier pump 20 can be configured as an injection pump for injecting the water-containing fluid 43 into the heat exchange section 41, and in particular into a flow volume 45 of the heat exchange section 41. The reservoir 44 is configured to store the water-containing fluid 43. Furthermore, an overflow is formed on the reservoir 44, via which water-containing fluid 43 can be conducted downstream of the turbine 16 into the cathode exhaust gas path 15. The humidity path 42 is configured to conduct the water-containing fluid 43 from the reservoir 44 into the heat exchange section 41. A blocking means 48 in the form of a valve is formed in the moisture path 42 downstream of the reservoir 44 in order to control, enable, and prevent fluid flow from the reservoir 44 into the heat exchange section 41.Upstream of the reservoir 44, a further blocking means 47 is configured in the moisture path 42 to prevent backflow of the water-containing fluid from the reservoir 44 into the cathode exhaust gas path 15 and / or to the fuel cell 11. The illustrated fuel cell system 10 has a water separator 49 for separating water from the cathode exhaust gas or from the cathode exhaust gas path 15, wherein the moisture path 42 is configured to conduct water from the water separator 49 into the reservoir 44.

[0049] The heat exchange section 41 shown in Fig. 1 defines a flow volume 45 through which the cathode exhaust gas flows, with a portion of the moisture path 42 extending through the flow volume 45. In the example shown, an end section of the moisture path 42 extends within the flow volume 45 parallel and coaxial to the heat exchange section 41 and thus to the corresponding section of the cathode exhaust gas path 15. The heat exchange section 41 shown has an inner wall section 31 and projections 33, with the projections 33 projecting from the inner wall section 31 into the flow volume 45 in a rib-like manner. The projections 33 are designed as a monolithic component of the heat exchange section 41 or a conduit wall of the heat exchange section 41. The heat exchange section 41 shown is made of plastic and has boron nitride fillers.

[0050] Fig. 2 shows a sectional view through a temperature control unit 40 according to the first embodiment. As shown in Fig. 2, the moisture path 42 in the flow volume 45 has lateral openings 46 that are configured to guide the water-containing fluid 43 from the moisture path 42 into the flow volume 45. More precisely, the openings 46 are designed such that the water-containing fluid 43 is guided in the form of water to the openings 46 and is sprayed through the openings 46 as a water mist into the flow volume 45. Fig. 3 shows a fuel cell system 10 according to a second embodiment. In the fuel cell system 10 shown in Fig. 3, the reservoir 44 has no inlet from the fuel cell system 10. Such a reservoir 44 can be integrated into the fuel cell system 10 particularly easily.

[0051] Fig. 4 shows a fuel cell system 10 according to a third embodiment. In the embodiment shown in Fig. 4, the reservoir 44 can be considered a water separator, for example, with an integrated water separator, in the cathode exhaust path 15, from which separated process water can be fed directly into the moisture path 42.

[0052] Fig. 5 and Fig. 6 show a fuel cell system 10 according to a fourth embodiment. In the fuel cell system 10 shown there, an open-pore foam structure 35 is configured in the flow volume 45. In the example shown, the foam structure is configured as an annular or tubular metal foam structure.

[0053] Fig. 7 and Fig. 8 illustrate a fuel cell system 10 according to a fifth embodiment. The fuel cell system 10 shown therein comprises an air duct 50 for guiding air along the temperature control unit 40. The illustrated air duct 50 is configured to introduce ambient air 52 from the environment of the fuel cell system 10 into the air duct 50. Via a connecting section 51, the air from the air duct 50 can be guided into the cathode exhaust path 15 downstream of the heat exchange section 41.

[0054] Figs. 9 and 10 show a fuel cell system 10 according to a sixth embodiment. The moisture path 42 of this embodiment is configured to direct the water-containing fluid 43 not only into the flow volume 45, but also into the air duct 50. Via the connecting section 51, the air mixed with the water-containing fluid 43 can be directed from the air duct 50 into the cathode exhaust path 15 downstream of the heat exchange section 41.

[0055] Fig. 11 shows a vehicle 100 in the form of a passenger car. The vehicle 100 has a fuel cell system 10 as described above, comprising a fuel cell 11 and two electric motors 60 for driving the vehicle 100, wherein the fuel cell system 10 is configured to supply power to the electric motors 60. The fuel cell system 10 further has a pressure vessel 70 from which fuel can be fed to the fuel cell 11. 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.

[0056] List of reference symbols

[0057] Fuel cell system fuel cell anode

[0058] Cathode Cathode inlet path Cathode exhaust path Turbine Compressor Intercooler Humidifier Humidifier pump Overflow Coolant bypass line Coolant cooler Coolant main line Coolant pump Inner wall section Protrusion Foam structure Temperature control unit Heat exchange section Humidity path Aqueous fluid Reservoir

[0059] Flow volume Opening Locking device Locking device Water separator Air duct Connection section Ambient air Electric motor Pressure vessel Vehicle

Claims

Patent claims 1. Fuel cell system (10), comprising: - a fuel cell (11) with an anode (12) and a cathode (13), - a cathode inlet path (14) for conducting cathode gas into the cathode (13), - a cathode exhaust path (15) for conducting cathode exhaust gas from the cathode (13) into the environment of the fuel cell system (10), - a coolant cooler (24), - a coolant main line (25) for conducting coolant from the coolant cooler (24) to the fuel cell (11) and for conducting coolant from the fuel cell (11) to the coolant cooler (24), - a temperature control unit (40) with a heat exchange section (41), wherein the heat exchange section (41) is designed as part of the cathode exhaust gas path (15), - a coolant secondary line (23) for conducting the coolant from the coolant cooler (24) into the temperature control unit (40) for heat transport from the coolant to cathode exhaust gas in the heat exchange section (41) and - a moisture path (42) for conducting a water-containing fluid (43) into the heat exchange section (41).

2. The fuel cell system (10) according to claim 1, comprising a reservoir (44) for storing the water-containing fluid (43), wherein the moisture path (42) is configured to conduct water-containing fluid (43) from the reservoir (44) into the heat exchange section (41).

3. Fuel cell system (10) according to one of the preceding claims, wherein the heat exchange section (41) defines a flow volume (45) through which the cathode exhaust gas flows, wherein at least a portion of the moisture path (42) extends through the flow volume (45).

4. The fuel cell system (10) according to claim 3, wherein the moisture path (42) in the flow volume (45) has at least one lateral opening (46) configured to direct the water-containing fluid (43) from the moisture path (42) into the flow volume (45).

5. Fuel cell system (10) according to one of claims 2 to 4, wherein a blocking means (48) is configured in the moisture path (42) downstream of the storage (44) is for preventing and releasing a fluid flow from the reservoir (44) into the heat exchange section (41).

6. Fuel cell system (10) according to one of the preceding claims, comprising an air guide (50) for guiding air along the temperature control unit (40), wherein the moisture path (42) is configured to guide the water-containing fluid (43) into the air guide (50).

7. The fuel cell system (10) according to claim 6, wherein the air duct (50) is configured to introduce ambient air (52) from the environment of the fuel cell system (10) into the air duct (50).

8. Fuel cell system (10) according to one of claims 6 to 7, comprising a connecting section (51) for introducing the air and / or the water-containing fluid (43) from the air guide (50) into the cathode exhaust gas path (15) downstream of the heat exchange section (41).

9. Fuel cell system (10) according to one of claims 2 to 8, comprising a water separator (49) for separating water from process gas of the fuel cell system (10), wherein the moisture path (42) is configured to conduct water from the water separator (49) into the reservoir (44).

10. Fuel cell system (10) according to one of claims 2 to 9, wherein a further blocking means (47) is configured in the moisture path (42) upstream of the reservoir (44) to prevent a backflow of the water-containing fluid from the reservoir (44).

11. Fuel cell system (10) according to one of the preceding claims, wherein the heat exchange section (41) has an inner wall section (31), defines a flow volume (45) and has projections (33) which protrude from the inner wall section (31) in a rib-like manner into the flow volume (45).

12. Fuel cell system (10) according to one of the preceding claims, wherein the heat exchange section (41) defines a flow volume (45), wherein an open-pore foam structure (35) is configured in the flow volume (45).

13. Fuel cell system (10) according to one of the preceding claims, wherein the heat exchange section (41) comprises boron nitride or consists at least partially of boron nitride.

14. A vehicle (100) comprising a fuel cell system (10) according to any one of the preceding claims and at least one electric motor (60) for driving the vehicle (100), wherein the fuel cell system (10) is configured to supply power to the at least one electric motor (60).

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