Method for operating a vehicle having a fuel cell system, and fuel cell system for same

Abstract

The invention relates to a method for operating a vehicle (200), in particular a utility vehicle, having a fuel cell system (100), wherein the fuel cell system (100) has a cathode-side flow path (16) which is fluidically connected to the surroundings (U) and which serves for transporting air from the surroundings to the fuel cell system and for transporting a cathode exhaust gas from the fuel cell system into the surroundings, and a fluid-conducting component (24) which is fluidically connected to the cathode-side flow path (16) and which is designed to receive accumulations of condensate (K) from the air or from the cathode exhaust gas (LK), and the vehicle (200) has a compressed-air supply (301) which is independent of the fuel cell system (100) and which is designed to provide dry compressed air (LT). It is proposed that the method involves injecting (407, 419) the dry compressed air (LT) by means of the compressed-air supply (301) into the cathode-side flow path (16) such that the dry compressed air (LT) flows through the fluid-conducting component (24), and any air or cathode exhaust gas and / or condensate (K) that is present is displaced out of the fluid-conducting component (24) toward the surroundings (U).

Description

[0001] Method for operating a vehicle with a fuel cell system, and fuel cell system for the same

[0002] The invention relates to a method for operating a vehicle, in particular a commercial vehicle, with a fuel cell system, wherein the fuel cell system has a cathode-side flow path which is fluidly connected to the environment for transporting air from the environment (U) to the fuel cell system and for transporting a cathode exhaust gas from the fuel cell system to the environment (U), and a fluid-conducting component which is fluidly connected to the cathode-side flow path and is designed to absorb accumulations of condensate from the air or the cathode exhaust gas, and the vehicle has a compressed air supply which is independent of the fuel cell system and is designed to provide dry compressed air.

[0003] Processes of the type mentioned above are generally known. In the course of the energy transition, hydrogen is a form of energy that is gaining increasing importance in the automotive sector, and especially in the commercial vehicle sector. A key challenge in the operation of fuel cell systems is the efficiency of the fuel cell system and its stability. Within the fuel cell system, compressor arrangements provide oxygen (air) as a cathode-side reactant, and expander arrangements remove the cathode exhaust gas leaving the fuel cell. The compressor and expander are often, but not necessarily, designed as integrated units.

[0004] After passing through the fuel cell, the cathode exhaust gas is a mixture of water and air, containing both droplet-shaped water and water bound in the air at a high saturation level. Before passing through the fuel cell of the fuel cell system, moisture may also be present in the ambient air, which enters the cathode-side flow path.

[0005] During the transport of air and / or cathode exhaust gas through the flow path, cooling of the air and / or cathode exhaust gas can occur, sometimes during operation, but especially after operation of the fuel cell system, causing water to condense. A pressure drop in the flow path also leads to water condensing from the air or cathode exhaust gas.

[0006] Although unintentional, there are inevitably always locations within the flow path of the fluid-carrying components of the fuel cell system where condensate can accumulate. Regarding the above-mentioned design of a fluid-carrying component to absorb accumulations of condensate from the air or the cathode gas, this is to be understood as meaning that the components also unintentionally have areas due to spatial or technical requirements where condensate can accumulate and is thus absorbed by the component.

[0007] Over the long term, water can lead to corrosion, but also to increased friction in moving fluid-carrying components, adversely affecting the efficiency and / or stability of the fluid-carrying components and thus the fuel cell system as a whole. If the condensate freezes within the fluid-carrying components, this can cause damage to the components and, in the worst case, lead to a malfunction of the fuel cell system.

[0008] Approaches are known from the prior art in which it was proposed to continue operating the compressor arrangements of the fuel cell system after the fuel cell system has been operated, thereby drying the fuel cell itself. Such systems are described, for example, in DE102020202283 A1 or DE102019214748 A1.

[0009] However, it has been shown that drying with the system's own compressor cannot guarantee that no water accumulates at critical points in the cathode-side flow path.

[0010] Accordingly, the object of the invention was to overcome the disadvantages described above as far as possible in a method of the type described above. In particular, the object of the invention was to provide a method that enables more reliable drying of the fluid-carrying components of the fuel cell system.

[0011] The invention solves this problem by proposing a method according to claim 1. In particular, it is proposed that the method comprises a step of blowing the compressed air into the cathode-side flow path by means of the compressed air supply, such that the compressed air flows through the fluid-carrying component and existing air and / or existing cathode exhaust gas and / or condensate is displaced from the fluid-carrying component towards the environment.

[0012] When dry compressed air is mentioned in connection with the invention, this means compressed air that is in class 6 or better according to ISO 8573-1:2010, preferably in class 4 or better.

[0013] The invention is based on the finding that, in the prior art, the air driven through the fuel cell by the compressor after operation still contains moisture, which can condense as a result of external influences, especially cooling of the system and / or the environment, and accumulate at the corresponding points in the fluid-carrying components. The invention addresses this and exploits the fact that a compressed air supply with dry compressed air is already present in the (commercial) vehicle in which the method described above is applied, because this is required, for example, for a braking system and / or an air suspension of the (commercial) vehicle.The invention proposes, instead of the air that could be provided by a possible compressor arrangement of the fuel cell system, and which always entrains a certain amount of residual moisture from the environment into the system, to use the already technically treated dry compressed air from the compressed air supply and to blow this into the flow path in such a way that the moisture of the air or the cathode exhaust gas still present in the system is expelled, and any accumulations of condensate within the fuel cell system are entrained and expelled from the system.

[0014] The invention takes advantage of the fact that the commercial vehicle's compressed air supply is already designed to provide compressed air at an operating pressure significantly higher than that provided by any compressor arrangements of the fuel cell system, and that this air can be injected into the flow path without additional pressurization at sufficiently high mass flows to ensure the entrainment of condensate accumulations. The necessary operating parameters of pressure and mass flow can be determined empirically in simple preliminary tests, and the amount of dry compressed air to be injected can be calibrated in a generally known manner.

[0015] The invention thus proposes a solution that can be used for all fluid-carrying components of the fuel cell system, provided that the respective fluid-carrying component can be structurally reached using compressed air lines.

[0016] The invention enables, and in preferred embodiments provides, the simultaneous or sequential removal of moisture from one or more fluid-carrying components by blowing in compressed air. In a preferred development of the invention, the method comprises the step of commissioning the fluid-carrying component, wherein the step of blowing in the dry compressed air is initiated before or simultaneously with the commissioning.

[0017] Preferably, the compressed air supply is configured to provide dry compressed air at an operating pressure of 8.0 bar or more, and the method comprises the step of reducing the pressure for injection to an injection pressure of 6.0 bar or less, preferably in a range of 3.0 bar to 5.5 bar. It has been found that, compared to the operating pressure typically provided by the compressed air supply, which is regularly above 8.0 bar, reducing the pressure results in better moisture and particle removal. In particular, injection is carried out at this reduced injection pressure and, at the same time, at the maximum available volume flow at the injection pressure in order to achieve the highest possible entrainment effect.

[0018] Preferably, the step of blowing in the dry compressed air is initiated and completed before the fluid-carrying component is commissioned. This ensures that the operation of the fuel cell system is free from interference from humidity or condensate.

[0019] In a further preferred embodiment, the method additionally comprises a step of deactivating the fluid-carrying component, wherein the step of blowing in the compressed air begins after or at the same time as the deactivation. Depending on the ambient conditions, it may be advantageous to carry out the step of blowing in the dry compressed air as soon as possible after the fluid-carrying component has been deactivated or immediately after the fluid-carrying component has been deactivated. However, the invention can also be advantageously used if a certain period of time is waited before blowing in the compressed air and after the fluid-carrying component has been deactivated so that the system can cool down to a certain extent. This also prevents the blowing of the dry compressed air into the cathode-side flow path from negatively affecting the operation of the fuel cell system.

[0020] Particularly preferably, the step of blowing in dry compressed air after the fluid-carrying component has been shut down is additionally carried out in a method which also includes blowing in dry compressed air before the fluid-carrying component is put into operation.

[0021] In a further preferred embodiment of the method, the step of blowing in the dry compressed air is carried out for a predetermined purging time, which is preferably in a range of five seconds or longer, more preferably in a range of ten seconds or longer, and particularly preferably in a range of 15 seconds or longer.

[0022] In a further preferred embodiment, the preferred ranges described above are limited upwards by a maximum rinsing time of 30 seconds or less.

[0023] Further, the purging time is preferably no longer than 20 seconds. It has been found that after the aforementioned purging times, no residual moisture remains in the system, or only such a low level of residual moisture remains that any adverse effect on the fuel cell system's operation is reliably ruled out.

[0024] Continuing the purging process beyond this time would no longer achieve any measurable benefit. Therefore, limiting the maximum purging duration conserves resources without any adverse effects. In a further preferred embodiment, the fluid-carrying component comprises an expander stage of a compressor arrangement of the fuel cell system, which preferably comprises an expander chamber and / or an expander wheel. Alternatively or additionally, the fluid-carrying component comprises an air bearing arrangement of a compressor arrangement of the fuel cell system, which preferably comprises one or more air bearings that are fluidly connected to the expander stage. Alternatively or additionally, the fluid-carrying component comprises a condensate separator of the fuel cell system.The condensate separator is preferably located in the cathode-side flow path of the cathode exhaust gas, for example, downstream of the fuel cell but upstream of an expander stage. The condensate separator, also called a droplet separator, can remove at least the droplets of the water present in the cathode exhaust gas. Blowing compressed air into the condensate separator improves and accelerates the removal of moisture from this component, as well as from the other aforementioned components. This also advantageously reduces the risk of damage due to freezing in winter.

[0025] Alternatively or additionally, the fluid-carrying component comprises a compressor stage of a compressor arrangement of the fuel cell system, which preferably comprises an expander chamber and / or an expander wheel. In compressor stages of the aforementioned type, the risk of damage due to moisture and / or particle accumulation is also advantageously reduced by injecting dry compressed air. For this purpose, the compressor stage preferably has corresponding outlet bores that can be opened during injection and closed during operation of the fuel cell system.

[0026] In a further preferred embodiment, the compressed air supply is assigned to a pneumatic braking system of the vehicle, in particular a multi-circuit braking system. If assigned to the multi-circuit braking system, the compressed air supply is preferably connected to an auxiliary consumer circuit of the braking system. The invention has been described above with reference to a first aspect of the method according to the invention.In a second aspect, the invention further relates to a fuel cell system for driving a vehicle, in particular a commercial vehicle, which has a compressed air supply that is independent of the fuel cell system and is designed to provide dry compressed air, wherein the fuel cell system has a cathode-side flow path that is fluidly connected to the environment for transporting air from the environment to the fuel cell system and for transporting a cathode exhaust gas from the fuel cell system to the environment, as well as a fluid-conducting component that is fluidly connected to the flow path and is designed to absorb accumulations of condensate from the air or the cathode gas.

[0027] The invention also achieves the object already described at the outset for the method in a fuel cell system of the aforementioned type, in that the fuel cell system has a valve arrangement which can be switched back and forth between a blocking position and a release position, wherein the valve arrangement is fluidically connected to the cathode-side flow path in the release position and is designed to connect the compressed air supply for blowing compressed air into the cathode-side flow path to the flow path in the release position in such a way that the compressed air flows through the fluid-carrying component and existing air or existing cathode exhaust gas and / or condensate from the fluid-carrying component is displaced towards the environment.

[0028] With regard to the fuel cell system, the invention utilizes the same advantages as the inventive method of the first aspect. Preferred embodiments of the method are simultaneously preferred embodiments of the fuel cell system of the second aspect, and vice versa. Therefore, to avoid repetition, reference is also made to the above statements and to the following statements on the fuel cell system with regard to the preferred embodiments of the method.

[0029] In a preferred development of the fuel cell system, the valve arrangement is controllable and configured to be connected to a control unit in a signal-conducting manner, wherein the control unit is preferably designed as a brake control unit or trailer brake control unit.

[0030] The control unit is preferably constructed in a generally known manner, i.e., it comprises processor means and one or more data memories, and is configured to at least partially execute the method according to the invention. Preferably, the control unit is configured to control the injection of compressed air into the cathode-side flow path in the method of the first aspect by controlling the valve arrangement.

[0031] The valve arrangement can be controlled pneumatically, electrically, electropneumatically or hydraulically.

[0032] Depending on whether one or more fluid-carrying components in the fuel cell system are to be freed of moisture by blowing in compressed air, the valve arrangement can comprise one or more controllable single- or multi-way valves. In preferred embodiments, the valve arrangement is configured to control one or more of these valves simultaneously or individually in order to free the fluid-carrying components that are fluidly connected to the valves of the valve arrangement from moisture.

[0033] In a further aspect, the invention relates to a vehicle, in particular a commercial vehicle, having a fuel cell system according to one of the preferred embodiments described above, and a control unit which is connected to the valve arrangement in a signal-conducting manner and is designed to control the valve arrangement for blowing in the compressed air in a method according to one of the preferred embodiments described above, wherein the control unit is preferably designed as a control unit or trailer control unit.

[0034] The vehicle utilizes the same advantages as the fuel cell system according to the invention of the second aspect and the method according to the invention of the first aspect. Preferred embodiments of the method and the fuel cell system are thus also preferred embodiments of the vehicle, and vice versa. Therefore, to avoid repetition, reference is made to the above explanations.

[0035] The invention is described in more detail below with reference to a preferred embodiment using the attached figures.

[0036] Here we show:

[0037] Fig. 1 is a schematic view of a vehicle with a fuel cell system according to a preferred embodiment, and

[0038] Fig. 2 is an exemplary schematic view of a preferred embodiment of the method according to the invention for operating a vehicle according to Fig. 1.

[0039] Fig. 1 schematically shows a vehicle 200, in particular a commercial vehicle. The vehicle 200 has a fuel cell system 100 and a braking system 300.

[0040] The fuel cell system 100 comprises a fuel cell 101, which is supplied with air L on the cathode side by a compressor arrangement 1. The compressor arrangement 1 comprises a compressor housing 3 in which a rotor shaft 5 is arranged. The rotor shaft 5 is driven by an electric machine 7 and is supported in a contact-free manner by an air bearing arrangement 9. The air bearing arrangement 9 comprises a plurality of air bearings, of which a first radial air bearing 9a and a second radial air bearing 9b are shown here as examples. The air bearing arrangement 9 expediently also comprises one or more axial air bearings, which, however, are not relevant for understanding the invention and are therefore hidden in Fig. 1 for better clarity.

[0041] The compressor arrangement 1 has a compressor stage 11 with a compressor chamber 13 and a compressor wheel 15 arranged therein, which, as a result of a rotation of the rotor shaft 5, sucks in air L from the environment U, compresses it and conveys it via a (first) cathode-side flow path 14 for reactant supply to the fuel cell 101.

[0042] After conversion in the fuel cell 101, a cathode exhaust gas LK is conveyed via a (second) cathode-side flow path 16 to an expander stage 17, which has an expander chamber 19 and an expander wheel 21 arranged therein. In the expander chamber 19, the cathode exhaust gas LK is expanded by means of the expander wheel 21 and subsequently conveyed to the environment U.

[0043] In the cathode-side flow path 16, between the fuel cell 101 and the expander stage 17, a condensate separator 23 is arranged, which is designed to collect drop-shaped water and any further accumulating condensate K and to discharge it from the cathode exhaust gas LK, preferably also towards the environment U.

[0044] Condensate K can accumulate not only in the condensate separator 23, but also in other areas of the flow path 16, for example, within the expander chamber 19, and also within the air bearing arrangement 9, which, due to its non-contact bearing design, is fluidly connected to the flow path 16 and there initially to the expander chamber 19. Therefore, the potential presence of condensate K is also indicated in these areas of the fuel cell system 100. The condensate separator 23, the expander stage 17, and the air bearing arrangement 9 are thus to be understood as examples of fluid-carrying components 24.

[0045] The vehicle 200 has a valve arrangement 25, which is fluidly connected to the fluid-carrying components 24 via dedicated fluid lines 27a, 27b, 27c.

[0046] The valve assembly 25 can be structurally assigned to the fuel cell system 100, but it can optionally also be structurally assigned to the braking system 300, depending on the installation conditions and customer requirements. The valve assembly 25 can also be arranged separately from both the braking system 300 and the fuel cell system 100 as a dedicated valve assembly at a convenient location in the vehicle 200. The functional assignment is decisive. The valve assembly 25 can optionally be designed to have one or more multi-way valves, or each with dedicated single-way valves.

[0047] The valve arrangement 25 can be switched back and forth between a release position F and a blocking position, and is configured, in the release position F, to establish a fluid-conducting connection between a compressed air supply 301 of the braking system 300 and the fluid-conducting components 24 in the cathode-side flow path 16, so that dry compressed air LT can be blown into the cathode-side flow path 16 and in particular into the fluid-conducting components 24. As a result, the dry compressed air LT displaces the potentially moisture-laden air of the condensate exhaust gas LK and also expels any accumulated condensate K from the fluid-conducting components 24.

[0048] The braking system preferably has a particulate filter 303, which is connected upstream of the valve arrangement 25. The braking system 300 has a (first) control unit 305, which is preferably designed as a brake control unit or trailer brake control unit, which is configured to switch the valve arrangement 25 from the blocking position S to the release position F and vice versa for a predetermined purging duration ts in order to carry out a targeted blowing process for drying the fluid-carrying components 24. For this purpose, the control unit 305 is connected in a signal-conducting manner to a (second) control unit 307, for example, a compressor control unit or fuel cell control unit, and is designed to be controllable by the latter.This makes it possible in a simple manner that whenever one, several or all of the fluid-carrying components 24 are to be put into operation or taken out of operation by commissioning or decommissioning the compressor arrangement 1, the valve arrangement 25 can be controlled to dry the fluid-carrying components 24, preferably using the method according to the invention, which is explained below with reference to Fig. 2.

[0049] In Figure 1, the functioning of the invention has been explained with a focus on the fluid-carrying components 24 in the second cathode-side flow path 16. In a further preferred embodiment, which is not illustrated separately here for reasons of clarity, the first cathode-side flow path 14 alternatively or additionally has a fluid-carrying component, such as the compressor chamber 13, which is blown dry in the same way by blowing in dry compressed air as the fluid-carrying components 24 in the second cathode-side flow path 16. In this regard, reference is made analogously to the above and the following explanations.

[0050] Fig. 2 shows a schematic process sequence in which the dry compressed air LT is blown into the cathode-side flow path 16 by means of the compressed air supply 301 in such a way that the fluid-carrying component 24 is flowed through by the compressed air LT and existing cathode exhaust gas LK and / or condensate K is displaced from the fluid-carrying component 24 in the direction of the environment U.

[0051] Initially, in step 401, a start request for the fuel cell system 101 is received. Based on this start request, in step 403, the second control unit 307 sends a control command Bvi to the first control unit 305. Subsequently, in step 405, the first control unit 305 controls the valve arrangement 25 to assume the release position F.

[0052] In step 407, the valve assembly 25 is then left in the release position for the purging duration Ts, and the fluid-carrying components 24 are dried by blowing dry compressed air LT into the flow path 16 until, at the end of the purging duration Ts, the valve assembly 25 is returned to its blocking position S (step 409). This can optionally be triggered by a control command Bvo from the second control unit 307 or controlled automatically by the first control unit 305.

[0053] In step 411, after the valve arrangement 25 has been successfully blocked, the fuel cell system 100 is put into operation, preferably by means of a control command BFCI of the second control unit 307.

[0054] If the fuel cell system 100 is to be shut down during ongoing operation, in step 413, upon a stop request, a control command BFCO is first sent to the electric machine 7 of the compressor assembly 1, preferably again triggered by the control unit 307. This stops operation and thus shuts down the fluid-carrying components 24.

[0055] At the same time or with a short delay thereafter, in step 415 the control command Bvi is sent from the second control unit 307 to the first control unit 305, whereupon in step 417 the valve arrangement 25 assumes its release position F. In step 419 the valve arrangement 25 can again remain in its release position F for the duration ts of the rinsing process in order to dry the cathode-side flow path 16 in the region of the fluid-carrying components 24, until in step 421 the valve arrangement 25 again assumes its blocking position S. This can be caused, as before, by a control command Bvo from the second control unit 307, or can be controlled automatically by the first control unit 305.

[0056] The programming effort required to implement the method is simple and efficient. The invention thus provides an extremely effective and simultaneously easy-to-implement system for increasing the stability and improving the efficiency of the fuel cell system 100 of the vehicle 200.

[0057] In the exemplary embodiment of Figures 1 and 2, a compressor arrangement 1 of a fuel cell system 100 is shown, wherein the fuel cell system 100 has a plurality of fluid-carrying components 24, each of which can (unintentionally) accumulate condensate K. However, the invention is not limited to the configuration shown, but is essentially implemented equally by systems having a smaller number of fluid-carrying components 24 or a larger number of fluid-carrying components 24.

[0058] Reference symbol (part of the description):

[0059] 1 Compressor arrangement

[0060] 3 Compressor housing

[0061] 5 Rotor shaft

[0062] 7 electric machine

[0063] 9 Air bearing arrangement

[0064] 9a, 9b first and second air bearing

[0065] 11 Compressor stage

[0066] 13 Compressor chamber

[0067] 14 Flow path

[0068] 15 Compressor wheel

[0069] 16 Flow path

[0070] 17 Expander stage

[0071] 19 Expander chamber

[0072] 21 Expander wheel

[0073] 23 condensate separators

[0074] 24 fluid-carrying components

[0075] 25 Valve arrangement

[0076] 27a, b, c Fluid lines

[0077] 100 fuel cell system

[0078] 101 Fuel Cell

[0079] 200 vehicles

[0080] 300 braking system

[0081] 301 Compressed air supply

[0082] 303 Particle filter

[0083] 305 (first) control unit, brake system

[0084] 307 (second) control unit, fuel cell system

[0085] 401 Step: Start request 403 Step: Control

[0086] 405 Step: Release position

[0087] 407 Step: Blowing in dry compressed air

[0088] 409 Step: Locking position

[0089] 411 Step: Commissioning of the fluid-carrying components

[0090] 413 Step: Stop request, decommissioning

[0091] 415: Step: Control

[0092] 417 Step: Release position

[0093] 419 Step: Blowing in dry compressed air

[0094] 421 step. Locked position

[0095] F Release position

[0096] K Condensate

[0097] L Air

[0098] LK cathode exhaust

[0099] LT compressed air

[0100] S Locking position ts Flushing time

[0101] U environment

[0102] BFCO control command, compressor arrangement

[0103] BFCI control command, compressor arrangement

[0104] Bvo control command, valve arrangement

[0105] Bvi control command, valve arrangement

Claims

Patent claims 1. A method for operating a vehicle (200), in particular a commercial vehicle, with a fuel cell system (100), wherein the fuel cell system (100) has a cathode-side flow path (16) fluidly connected to the environment (U) for transporting air from the environment (U) to the fuel cell system (100) and for transporting a cathode exhaust gas (LK) from the fuel cell system (100) to the environment (U), as well as a fluid-conducting component (24) fluidly connected to the cathode-side flow path (16) and configured to absorb accumulations of condensate (K) from the air (L) or from the cathode exhaust gas (LK), and the vehicle (200) has a compressed air supply (301) independent of the fuel cell system (100) and configured to provide dry compressed air (LT), characterized in that the method comprises: Blowing (407,419) the dry compressed air (LT) by means of the compressed air supply (301) into the cathode-side flow path (16) in such a way that the fluid-carrying component (24) is flowed through by the dry compressed air (LT) and existing air (L) or existing cathode exhaust gas (LK) and / or condensate (K) is displaced from the fluid-carrying component (24) in the direction of the environment (U).

2. Method according to claim 1, comprising: Commissioning (411) of the fluid-carrying component (24), wherein the step (407) of blowing in the dry compressed air (LT) is started before, or at the same time as, the commissioning (411).

3. Method according to claim 1 or 2, wherein the step (407) of blowing in the dry compressed air (LT) is started and completed before the fluid-carrying component is put into operation (411).

4. A method according to any one of the preceding claims, comprising: Decommissioning (413) the fluid-carrying component (24), wherein the step (419) of blowing in the dry compressed air (LT) is started after, or simultaneously with, the decommissioning (413).

5. Method according to one of the preceding claims, wherein the step (407, 419) of blowing in the dry compressed air (LT) is carried out for a predetermined purging time (ts), which is preferably in a range of 5 s or longer, more preferably 10 s or longer, particularly preferably 15 s or longer.

6. Method according to one of the preceding claims, wherein the fluid-carrying component (24) - an expander stage (11) of a compressor arrangement (1) of the fuel cell system (100), - an air bearing arrangement (9) of a compressor arrangement (1) of the fuel cell system (100), - a condensate separator (23) of the fuel cell system (100), and / or - a compressor stage of a compressor arrangement (1) of the fuel cell system (100).

7. Method according to one of the preceding claims, wherein the compressed air supply (301) is assigned to a pneumatic braking system (300) of the vehicle (200), in particular a multi-circuit braking system.

8. Fuel cell system (100) for driving a vehicle (200), in particular a commercial vehicle, which has a compressed air supply (301) independent of the fuel cell system (100) and designed to provide dry compressed air (LT), wherein the fuel cell system (100) has a cathode-side flow path (16) connected in a fluid-conducting manner to the environment (U) for transporting air from the environment (U) to Fuel cell system, and for transporting a cathode exhaust gas (LK) from the fuel cell system into the environment (U), and a fluid-conducting component (24) which is fluid-conductingly connected to the cathode-side flow path (16) and is designed to remove accumulations of condensate (K) from the air orthe cathode exhaust gas (LK), characterized in that the vehicle (200), preferably the fuel cell system (100), has a valve arrangement (25) which can be switched back and forth between a blocking position (S) and a release position (F), wherein the valve arrangement (25) is fluidically connected to the cathode-side flow path (16) in the release position (F) and is designed to connect the compressed air supply (301) for blowing dry compressed air (LT) into the cathode-side flow path (16) to the flow path (16) in the release position (F) in such a way that the dry compressed air (LT) flows through the fluid-carrying component (24) and existing air or existing cathode exhaust gas (LK) and / or condensate (K) therefrom is displaced from the fluid-carrying component (24) in the direction of the environment (U).

9. Fuel cell system (100) according to claim 8, characterized in that the valve arrangement (25) is controllable and is designed to be connected in a signal-conducting manner to a control unit (305), wherein the control unit (305) is preferably designed as a brake control unit or trailer brake control unit.

10. Vehicle (200), in particular a commercial vehicle, with a fuel cell system (100) according to claim 9 and a control unit (305) which is connected to the valve arrangement (25) in a signal-conducting manner and is designed to control the valve arrangement (25) for blowing in the dry compressed air (LT) in a method according to one of claims 1 to 7, wherein the control unit (305) is preferably designed as a brake control unit or trailer brake control unit.

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