Method for coping with flooding of anode of fuel cell stack

Abstract

The invention relates to a method (200) for handling flooding of an anode (140) of a fuel cell stack (10) of a fuel cell assembly (1), in particular of a fuel cell vehicle, in which a current operating program (201) of the fuel cell assembly (1) is carried out by a control device of the fuel cell assembly (1), when there is a risk of flooding of the anode (140) or when flooding of the anode (140) is diagnosed, a reactive purge-drain routine (202) is set in the operating program (201), by means of which the avoidance or release of flooding of the anode (140) is prioritized and is coped with countermeasures.

Description

Field of the Invention

[0001] The present invention relates to a method for combating flooding of the anode of a fuel cell stack of a fuel cell assembly, in particular for a fuel cell vehicle. Furthermore, the present invention also relates to a fuel cell assembly, a fuel cell system, and a fuel cell vehicle. Background Art

[0002] In a low-temperature polymer electrolyte fuel cell of a fuel cell assembly (stationary or mobile), such as a fuel cell system of a fuel cell vehicle for example, two reactants of two operating media are electrochemically converted into electrical energy and heat. Herein, the fuel cell includes at least one membrane electrode assembly (MEA). Generally, the fuel cell is constructed with a plurality of membrane electrode assemblies arranged in a stack and bipolar plates arranged therebetween (a fuel cell stack or a stack having a plurality of individual fuel cells).

[0003] Problem to be Solved

[0004] During the operation of the fuel cell stack, water is generated on the cathode side, and a part of the water is transported through the membrane electrode assembly to the anode of the fuel cell stack. Thus, liquid water may accumulate at the anode. A relatively large (local) accumulation of water must be avoided in order to prevent flooding, and thus to avoid the risk of hydrogen depletion in the anode. Hydrogen depletion may lead to serious degradation or even failure of the fuel cell stack. - One task of the present invention is to combat (local) flooding of the anode. Summary of the Invention

[0005] The task of the present invention is solved by a method for combating flooding of the anode of a fuel cell stack of a fuel cell assembly, in particular for a fuel cell vehicle; and by means of a fuel cell assembly, a fuel cell system, or a fuel cell vehicle. - Advantageous extensions, additional features, and / or advantages of the present invention are derived from the dependent claims and the following description.

[0006] In the method according to the present invention for combating flooding of the anode, the control device for the fuel cell assembly executes the current operating procedure of the fuel cell assembly, wherein, when there is a risk of flooding of the anode or when flooding of the anode is diagnosed, a reactive purge-drain routine is set in the operating procedure, and by means of this purge-drain routine, the avoidance or elimination of flooding of the anode is prioritized and countermeasures are taken to deal with it. The control device is in particular the control device of the following fuel cell system: the fuel cell assembly belongs to this fuel cell system.

[0007] The operating program can be configured as the normal operating program of the fuel cell assembly or other operating programs. Here, the operating program can be configured as the anode operating program of the anode supply device of the fuel cell assembly. When executing the reactive purge-drain routine, the anode operating program can be supported by other operating programs of the fuel cell assembly (such as the operating program of the cathode).

[0008] This means that in the method according to the invention, the fuel cell assembly, in particular the anode supply device of the fuel cell assembly, is preferentially operated in such a way that an impending (local) flooding of the anode is avoided or a (locally) flooded anode is relieved of the water present therein. This further means that the method for dealing with the flooding of the anode comprises two aspects, namely avoiding the risk of flooding and relieving the existing flooding.

[0009] Within the reactive purge-drain routine, in the absence of anode flooding, the avoidance of the risk of anode flooding can be prioritized. In addition, in the reactive purge-drain routine, the relief of anode flooding can be prioritized over the avoidance of the risk of anode flooding. In addition, when extensive anode flooding is predicted, emergency measures for the fuel cell stack can be initiated. Such emergency measures can be the minimum operation of the fuel cell assembly, the battery operation of the fuel cell vehicle possibly in the case of shutdown of the fuel cell assembly, etc.

[0010] In this method, a preventive purge-drain strategy and a reactive purge-drain strategy for the anode can be distinguished. Here, the preventive purge-drain strategy can be part of the global strategy of the operating program of the fuel cell assembly. In addition, the reactive purge-drain strategy may not be part of the global strategy of the operating program of the fuel cell assembly. In addition, based on the reactive purge-drain strategy, a reactive purge-drain routine can be set in the operating program. - In this operating program, for example, the consumption, performance, noise, vibration and noise, vibration and harshness (NVH) of the fuel cell assembly are prioritized, and the avoidance of anode flooding is initially secondary, but of course not unimportant.

[0011] After the risk of flooding has been avoided in time and / or after the anode flooding has been relieved in time, the operating program set so far or other operating programs of the fuel cell assembly can be executed.

[0012] Within the scope of the present invention, it has been determined that the impact of anode flooding is manifested as a sudden drop (einbrechen) in the cell voltage of the fuel cell stack, which can be diagnosed, for example, by monitoring the cell voltage. Usually, flooding is also accompanied by an increase in the pressure loss in the flow field on the anode side of the fuel cell stack, which can be detected by measuring the pressure difference. This means that the presence of the risk of anode flooding or the diagnosis of anode flooding can be detected or sensed by observing the cell voltage of the fuel cell stack, especially a sudden drop, by the pressure loss on the anode side of the fuel cell stack, especially the pressure loss in the flow field on the anode side, etc.

[0013] Countermeasures for avoiding or relieving anode flooding may include sending a forced drainage request; opening the drain valve of the anode supply device; increasing the air mass flow rate in the cathode; reducing, preventing, or stopping the recirculation in the anode supply device; conveying hydrogen only through the ejector pump bypass; and / or closing the recirculation valve.

[0014] Furthermore, when the anode supply device has a fluid conveying device at / in the anode recirculation path, countermeasures for avoiding or relieving anode flooding may include reducing the rotational speed of the fluid conveying device, shutting off the fluid conveying device, and / or closing the recirculation valve. Of course, the above-mentioned countermeasures can also be taken here.

[0015] The anode supply device may: have exactly one, at least one, exactly two, or at least two hydrogen metering valves; have a hydrogen metering valve in the ejector pump bypass; have no ejector pump, have exactly one or at least one ejector pump; have an anode recirculation path and / or have a recirculation valve at / in the anode recirculation path. Here, the recirculation valve may be arranged upstream or downstream of the fluid conveying device (of course, only in the case where there is a fluid conveying device). This means that the anode supply device may have no fluid conveying device or have a fluid conveying device at / in the anode recirculation path. Especially if no recirculation valve is provided, it is preferred that the fluid impeller of the fluid conveying device cannot be flowed through by the fluid or can only be flowed through by the fluid in the case of a significantly increased pressure loss, for example, in the case of a Roots blower case. Description of the Drawings

[0016] In the following, the present invention will be explained in more detail according to embodiments with reference to the attached schematic and non - to - scale drawings. In the present invention, a feature can be configured as positive, i.e., present, or negative, i.e., absent. In this specification, if the absence is not emphasized according to the present invention, the negative feature will not be explicitly described as a feature. This means that the present invention actually made and not constructed by the prior art lies in the omission of this feature. The absence of a feature (negative feature) in an embodiment shows that this feature may be (for a person skilled in the art) optional. - Shown in the merely exemplary figures of the drawings:

[0017] Figure 1 A simplified block diagram shows an embodiment of a fuel cell assembly of a fuel cell system for a fuel cell vehicle;

[0018] Figure 2 A possible flowchart showing a method according to the present invention for dealing with flooding of the anode of a fuel cell stack of a fuel cell assembly;

[0019] Figures 3 to 6 Simplified block diagrams respectively show an embodiment of an anode supply device of a fuel cell stack of a fuel cell assembly for a fuel cell system. Detailed description of specific embodiments

[0020] The present invention will be explained in more detail according to a method (see Figure 2 ) for dealing with flooding of the anode 140 of the fuel cell stack 10 of the fuel cell assembly 1, which fuel cell assembly is particularly for a low - temperature polymer electrolyte fuel cell system of a fuel cell vehicle (i.e., a motor vehicle having a fuel cell or a fuel cell system). Only those parts of the fuel cell system that are necessary for understanding the present invention are shown in the drawings.

[0021] Although the present invention has been described and illustrated in more detail by preferred embodiments in terms of details, the present invention is not limited by the disclosed embodiments. Other variant solutions can be derived therefrom without departing from the scope of protection of the present invention. In particular, the present invention can also be applied to other mobile or stationary fuel cell assemblies 1 or fuel cell systems.

[0022] Figure 1 A fuel cell assembly 1 is shown according to an embodiment, which has at least one, in particular a plurality of, electro - chemical single fuel cells 11 (single cells 11) bundled into a fuel cell stack 10, and these single cells are placed in a preferably fluid - tight stack housing 16. Each single cell 11 includes an electrode chamber 12 configured as an anode chamber 12 and an electrode chamber 13 configured as a cathode chamber 13, which are spatially and electrically separated from each other by the membrane of the membrane - electrode unit 15.

[0023] A bipolar plate 14 is respectively arranged between two membrane electrode units 15, 15 (including the associated anode chamber 12 and cathode chamber 13) that are directly adjacent to each other. The bipolar plate is particularly used for introducing / extracting the operating media 3, 5 into / from the anode chamber 12 of the first single cell 11 and the cathode chamber 13 of the second single cell 11 directly adjacent thereto, and furthermore realizes the electrical connection between these single cells 11, 11. - The cathode chambers 13 and possibly their common inflow region or their electrodes form the cathode 130 of the fuel cell stack 10 here, and the anode chambers 12 and possibly their common inflow region or their electrodes form the anode 140 of the fuel cell stack 10 here.

[0024] To supply the actual operating media 3 (anode operating medium, actual fuel), 5 (cathode operating medium, usually air) to the fuel cell stack 10, the fuel cell assembly 1 has an anode supply device 20 and a cathode supply device 30.

[0025] The anode supply device 20 particularly includes: a fuel storage 23 for the anode operating medium 3 (inflow); an anode supply path 21 having a pressure reducer, a shut-off valve, and / or a metering valve 27 (exemplarily) and an ejector pump 24 (jet pump 24, injector 24); an anode exhaust path 22 for the anode exhaust medium 4 (outflow, usually flowing out to the surroundings 2); a fuel recirculation path 25 preferably having a fluid delivery device 26 arranged therein; possibly a water separator and possibly a water container.

[0026] The cathode supply device 30 particularly includes: a cathode supply path 31 for the cathode operating medium 5 (inflow, usually from the surroundings 2), preferably having a fluid delivery device 33; a cathode exhaust path 32 for the cathode exhaust medium 6 (outflow, usually flowing out to the surroundings 2), preferably having a turbine 34, especially for the fluid delivery device 33; preferably a humidity transfer device 36, especially a gas-to-gas humidifier 36; possibly a cathode-side stack bypass 35 (exhaust gas gate 35) between the cathode supply path 31 and the cathode exhaust path 22, having a bypass valve 37; possibly a water separator and possibly a water container.

[0027] The fuel cell assembly 1 in particular also includes a coolant supply device 40 of a thermal system, in particular of a thermal system of a fuel cell vehicle, by means of which the fuel cell stack 10 can preferably be thermally connected to a cooling circuit for temperature regulation (Temperieren) via its bipolar plates 14 (coolant path 43). The coolant supply device 40 includes a coolant inlet path 41 and a coolant outlet path 42. The conveyance of the coolant 7 (inflow), 8 (outflow) circulating in the coolant supply device 40 is preferably effected by means of at least one coolant conveyance device 44.

[0028] In addition to the fuel cell assembly 1, the fuel cell system also includes peripheral system components, such as a control device, which can be a control device of the fuel cell vehicle itself.

[0029] Various topologies of the anode supply device 20 (usually also referred to as the hydrogen system 20) for the fuel cell assembly 1 are known, for example, an anode supply device 20 with active recirculation (fluid conveyance device 26, in particular a hydrogen recirculation blower 26), an anode supply device 20 with passive recirculation, an anode supply device 20 with active and passive recirculation, an anode supply device 20 with one or more sites for discharging anode condensate, an anode supply device 20 with separate or combined purge valves and drain valves, etc.

[0030] The anode supply device 20 with passive recirculation is usually equipped with an ejector pump 24 (see Figure 1 the anode recirculation path 25 without a fluid conveyance device 26). The primary mass flow of the hydrogen metering valve (27) is used here to convey a secondary mass flow (recirculation mass flow). Here, there is an anode supply device 20 with an arrangement of one or more hydrogen metering valves (27) and an ejector pump 24. An additional hydrogen metering valve can be provided here, by means of which hydrogen can be directly conveyed to the anode supply device 20. Additionally, a recirculation valve can be provided, by means of which recirculation through the anode recirculation path 25 can be prevented. - See also below Figures 3 to 6 .

[0031] In principle, the operation of the anode supply device 20 should be carried out in such a way that (local) flooding of the anode 140 is avoided (for example, by a conservative purge-drain strategy, etc.), which usually leads to a compromise between system performance, efficiency, and the service life of the fuel cell stack 10. Due to the various operating states of mobile fuel cell systems in particular, for the rare case of anode flooding, an appropriate system reaction must be provided in order to avoid increased degradation of the fuel cell stack 10. Here, the above compromise can be deviated from, so as to prioritize the performance indicator of service life.

[0032] Therefore, the flooding of the anode 140 that has occurred or (with high probability) is about to occur should be ended as quickly as possible by means of one or more countermeasures. - According to the invention, the control device (FCCU: Fuel Cell Control Unit) differentiates between a preventive purge-drain strategy (conventional purge-drain-strategy) and a reactive purge-drain strategy (forced drain request / fast drain). The preventive purge-drain strategy is embodied in the operating program or reference operating program of the fuel cell assembly 1 or the anode supply device 20, in particular the normal operating program, or at least in one time part thereof.

[0033] In the reactive purge-drain strategy, when the risk of flooding is high or very high or the flooding of the anode 140 has occurred or has been diagnosed, the avoidance or stoppage of the flooding of the anode 140 is prioritized. Thereby, the control device prioritizes the avoidance or elimination of the flooding of the anode 140 relative to other control and / or regulation objectives (such as consumption, performance, noise, vibration and harshness (NVH: Noise Vibration Harshness), etc.).

[0034] In the reactive path 202 of the purge-drain strategy (see also Figure 2 its description and Figures 3 to 6 ), the following countermeasures can be taken exemplarily, namely measures for avoiding or eliminating the flooding of the anode 140.

[0035] Send a forced drain request to the control device and / or open the drain valve 160 through the control device. Here, depending on the operating state of the cathode supply device 30, it may be necessary to quickly increase the air mass flow rate in the cathode 130 when necessary to ensure favorable dilution conditions for the hydrogen in the exhaust gases 4, 6. This can be carried out, for example, by eliminating throttling in the cathode path and / or opening the throttle valve in the cathode supply device 30, etc.

[0036] Furthermore, as a countermeasure, the recirculation in the anode supply device 20 can be reduced, prevented or stopped. Thereby, the water transfer from the anode outlet to the anode inlet is reduced or prevented, so that the anode humidity can be quickly reduced. In addition, hydrogen can be supplied through the bypass hydrogen metering valve 122 instead of the hydrogen metering valve 120 of the ejector pump 130. In addition, of course, the recirculation valve 152 can be closed only if it exists.

[0037] For a fuel cell assembly 1 having a fluid delivery device 26 in an anode recirculation path 150, it is possible to reduce the rotational speed of the fluid delivery device 26 or, especially when the fluid impeller of the fluid delivery device 26 cannot be flowed through by the fluid or can only be flowed through with a significantly increased pressure loss, to switch off the fluid delivery device 26, for example in the case of a Roots blower. In addition, of course, the recirculation valve 152 can be closed only if it is present.

[0038] An advantage of the present invention lies especially in an extended service life of the fuel cell stack 10 by avoiding flooding of the anode 140 or by means of at least one rapid countermeasure in order to prevent a prolonged and continuous flooding of the anode 140. In addition, the present invention has a positive effect on hydrogen consumption because, compared to the prior art, in the normal operating program 201, the drainage process can be triggered at longer intervals or at longer time intervals, so that the hydrogen losses that are usually inevitable during drainage can be reduced.

[0039] Figure 2 A possible embodiment of a method 200 for countering flooding of the anode 140 is shown. First, the method 200 operates as a known operating program 201, for example as a normal operating program 201, in which the anode 140 is operated in a conventional manner, i.e., for example, purged (cleaned) and drained (emptied) within a specific time window and depending on the load of the fuel cell stack 10, etc. Here, in Figure 2 the preventive purge-drain strategy is shown by a solid connecting line and the reactive purge-drain strategy is represented by a dashed connecting line.

[0040] Within the scope of the method 200 as a known operating program 201, in a (first) step 211, the anode state (amount of liquid water) is monitored or estimated with respect to the water present there. In a subsequent (second) step 221, it is checked whether the water present in the anode 140 is within the target range. If this is the case (yes: +), the query ends and the method returns. If this is not the case (no: -), the method continues in an optional (third) step 231.

[0041] In this step 231, it is checked whether the deviation of the water present in the anode 140 is a minor deviation or an acceptable deviation. If this is the case (yes: +), the control / regulation (interval, time interval for opening / closing, etc.) of the drain valve 160 can be adjusted in a subsequent (fourth) step 241. Then, chronologically, the method returns. Instead of completing step 241, the method can alternatively also return directly from step 231. - Steps 211, 221, 231, 241 are preferably carried out within the scope of the preventive purge-drain strategy.

[0042] If the deviation of the water present in the anode 140 identified in step 231 is not a minor deviation or not an acceptable deviation (No: -), a reactive purge - drain strategy is set (dashed connecting line 202 starting from step 231). Additionally, in this reactive purge - drain strategy, step 212 can be set in method 200 in parallel with the operating program 201, in which the flooding of the anode 140 can be diagnosed or detected (e.g., by battery voltage monitoring, pressure difference measurement, etc., see above). In both cases, however, especially in the second case, rapid countermeasures are initiated.

[0043] In both cases, method 200 for dealing with the flooding of the anode 140 reaches (countermeasure) step 222, in which the high risk of flooding of the anode 140 is stopped / avoided, or the flooded anode 140 is relieved of the liquid water present therein; see above. If successful, the method can return, i.e., reset the operating program 201, especially the normal operating program 201.

[0044] According to the invention, in the case of a high risk of flooding of the anode 140 or when the flooding of the anode 140 has been diagnosed (detected / perceived), the preventive path (solid connecting line) leads to sending a forced drainage request, i.e., it merges into the reactive path (dashed connecting line). Thus, in the control device, the avoidance or relief of flooding is prioritized relative to other control and / or regulation objectives (e.g., consumption, performance, noise, vibration, and harshness, etc.).

[0045] For example, the applicable anode supply device 20 differs, for example, in the number of hydrogen metering valves 120, 122. They can be equipped with or without a fluid delivery device 26, and they can be provided with or without a recirculation valve 152, where the position of the recirculation valve 152 may change if necessary. See Figures 3 to 6 where, of course, other combinations are possible.

[0046] Thus, Figure 3 shows an embodiment of the anode supply device 20, which has a pressure reducer 110 or a pressure regulator 110, two hydrogen metering valves 120, 122, and a single jet pump 130 in the anode supply path 21. Here, the hydrogen metering valve 122 is arranged in a jet pump bypass 170 that bypasses the jet pump 130. The recirculation through the anode recirculation line 150 takes place completely passively through the jet pump 130 and depends on the mass flow rate of the hydrogen metering valve 120 and the selected geometry of the jet pump 130. Additionally, a recirculation valve 152 is provided at / in the anode recirculation line 150, by means of which the anode recirculation line 150 can be blocked or possibly only partially blocked.

[0047] Figure 4 The embodiment of Figure 3 is extended by a fluid delivery device 26 in the anode recirculation line 150, wherein the recirculation valve 152 is arranged upstream of the fluid delivery device 26 at / in the anode recirculation line 150. Relative to Figure 4 the embodiment of Figure 5 in the embodiment of

[0048] Figure 6 the embodiment shows an anode supply device 20 which has a pressure reducer 110 or a pressure regulator 110, a single hydrogen metering valve 120 in the anode supply path 21 and no jet pump. The recirculation via the anode recirculation line 150 is carried out actively by the fluid delivery device 26. Furthermore, a recirculation valve 152 is preferably arranged upstream of the fluid delivery device 26 at / in the anode recirculation line 150. The fluid delivery device 26 can be configured hydraulically as a rotary piston compressor which cannot be flowed through by the fluid or cannot be flowed through by the fluid without significant pressure losses.

[0049] For stopping the recirculation (and thus the cause of flooding) in the anode supply device 20 having the fluid delivery device 26, it is advantageous if the fluid delivery device 26 cannot be flowed through by the fluid or cannot be flowed through by the fluid without significant pressure losses (preferably greater than 200 mbar at the nominal point). In the range of the jet pump 130, it is advantageous if the hydrogen metering valve 122 can meter fresh hydrogen directly into the anode circuit without necessarily generating a recirculation flow (e.g., jet pump bypass 170).

Claims

1. A method (200) for dealing with flooding of the anode (140) of a fuel cell stack (10) of a fuel cell assembly (1), especially for a fuel cell vehicle, wherein, the current operating program (201) of the fuel cell assembly (1) is executed by a control device of the fuel cell assembly (1), characterized in that, when there is a risk of flooding of the anode (140) or when flooding of the anode (140) is diagnosed, a reactive purge - drainage routine (202) is set in the operating program (201), and through the reactive purge - drainage routine, preferably the avoidance or relief of flooding of the anode (140) is achieved and countermeasures are taken to deal with it.

2. The method (200) according to the above - mentioned claim, characterized in that, · the operating program (201) is configured as the normal operating program (201) or other operating program (201) of the fuel cell assembly (1); · the operating program (201) is configured as the anode operating program of the anode supply device (20) of the fuel cell assembly (1); and / or · when the reactive purge - drainage routine (202) is executed, the anode operating program is supported by other operating programs of the fuel cell assembly (1).

3. The method (200) according to any one of the above - mentioned claims, characterized in that, within the reactive purge - drainage routine (202): · when there is no flooding of the anode (140), preferably the risk of flooding of the anode (140) is avoided; · the relief of flooding of the anode (140) is preferred over the avoidance of the risk of flooding of the anode (140); or · when extensive flooding of the anode (140) is predicted, emergency measures for the fuel cell stack (10) are initiated.

4. The method (200) according to any one of the above - mentioned claims, characterized in that, a preventive purge - drainage strategy and a reactive purge - drainage strategy for the anode (140) are distinguished, wherein: · the preventive purge - drainage strategy is part of the global strategy of the operating program of the fuel cell assembly (1); · the reactive purge - drainage strategy is not part of the global strategy of the operating program of the fuel cell assembly (1); and / or · based on the reactive purge - drainage strategy, the reactive purge - drainage routine (202) is set in the operating program (201).

5. The method (200) according to any one of the above - mentioned claims, characterized in that, the operating program (201) set so far or other operating programs of the fuel cell assembly are executed after the avoidance of the risk of flooding of the anode (140) in time and / or after the relief of flooding of the anode (140) in time.

6. The method (200) according to any one of the above - mentioned claims, characterized in that, The presence of a risk of flooding of the anode (140) or the diagnosis of flooding of the anode (140) is detected or sensed by observing the cell voltage of the fuel cell stack (10), in particular a sudden drop, and / or by a pressure loss on the anode side of the fuel cell stack (10), in particular a pressure loss in the flow field on the anode side.

7. The method (200) according to any one of the preceding claims, characterized in that the countermeasures for avoiding or removing flooding of the anode (140) include: · Sending a forced drainage request; · Opening the drain valve (160) of the anode supply device (20); · Increasing the air mass flow rate in the cathode; · Reducing, preventing or stopping the recirculation in the anode supply device (20); · Delivering hydrogen only through the ejector bypass (170); and / or · Closing the recirculation valve (152).

8. The method (200) according to any one of the preceding claims, characterized in that when the anode supply device (20) has a fluid delivery device (26) at / in the anode recirculation path, the countermeasures for avoiding or removing flooding of the anode (140) include: · Reducing the rotational speed of the fluid delivery device (26); · Shutting off the fluid delivery device (26); and / or · Closing the recirculation valve (152).

9. The method (200) according to any one of the preceding claims, characterized in that the anode supply device (20): · Has exactly one, at least one, exactly two or at least two hydrogen metering valves (120, 122); · Has a hydrogen metering valve (122) in the ejector bypass (170); · Does not have an ejector (130), has exactly one or at least one ejector (130); ● Has an anode recirculation path (150); · Has a recirculation valve (152) at / in the anode recirculation path (150); and / or · Does not have a fluid delivery device (26) at / in the anode recirculation path (150) or has a fluid delivery device (26).

10. A fuel cell assembly (1), a fuel cell system or a fuel cell vehicle, characterized in that the method (200) for coping with flooding of the anode (140) of its fuel cell stack (10) according to any one of the preceding claims can be performed and / or is performed by the fuel cell assembly (1), the fuel cell system or the fuel cell vehicle.

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