DE102021203438A1 - media merge device - Google Patents

Abstract

The invention relates to a media combining device (M) for a fuel cell system (100), with a container (MB) for mixing and/or examining media flows, on which the following elements are arranged: a line connection (M1) for an exhaust air line (12) for discharge an exhaust air from at least one fuel cell (101) of the fuel cell system (100), at least one line connection (MQ1) for at least one purge and/or drain line (L1) of a purge and/or drain system (Q1) of the fuel cell system (100), a line outlet (M2) for discharging media streams from the container (MB), and a fuel sensor (S) for sensing a fuel content in the container (MB).

Description

The invention relates to a media combining device for a fuel cell system according to the independent device claim and a corresponding fuel cell system, for example for a vehicle, with a corresponding media combining device according to the independent device claim. Furthermore, the invention relates to advantageous uses of a corresponding media combining device according to the independent claims as well as a vehicle with a corresponding fuel cell system according to the further independent device claim.

State of the art

Fuel cell systems are known in principle, also as energy suppliers in vehicles. In fuel cell systems i. i.e. R. uses oxygen from the ambient air as the oxidizing agent and hydrogen as the reducing agent or fuel in order to react to form water (or water vapor) in the fuel cell stack of the system and thus to supply electrical power by electrochemical conversion. The ambient air is usually provided to the fuel cell stack by means of a cathode system with an air compression system. The hydrogen is i. i.e. R. stored in a high-pressure tank (e.g. 700 bar) and fed to the fuel cell stack via lines and valves and recirculated in a loop-like anode path of an anode system. During operation, the anode loop must be purged and drained periodically during operation in order to reduce the increasing nitrogen content (through diffusion across the membrane) and the accumulation of water in the anode. Part of the purge gas is also hydrogen, which is why the purge gas is fed into the air system exhaust gas duct and is diluted there by the air mass flow to such an extent that no explosive mixture can form.

The fuel cell stack usually includes several fuel cells that are mutually sealed with many seals. However, these seals are subject to temperature changes, pressure changes, etc. and age accordingly. Therefore, the fuel cell stacks are usually not tight in the absolute sense. On the other hand, the high-pressure tanks for storing the hydrogen or their fittings, actuators, sensors and/or pipelines can leak.

Since hydrogen is very volatile and can form an explosive mixture with air, especially in confined or closed rooms, it is safety-relevant to detect any hydrogen leaks with certainty. Several hydrogen sensors are usually installed to detect hydrogen leakage. These sensors have a significant cost associated with them. When used in the vehicle, several hydrogen sensors are usually required at different locations. In addition, if hydrogen leakage cannot be ruled out in confined spaces, i. i.e. R. Ventilation systems used to guarantee a sufficiently high air exchange and to avoid hydrogen accumulations that could lead to explosive mixtures.

Another system-inherent property in fuel cell systems is the formation of product water (reaction product of hydrogen and oxygen from the air).

Disclosure of Invention

According to a first aspect, the invention provides a media combining device for a fuel cell system with the features of the independent device claim and according to a second aspect a corresponding fuel cell system with the features of the independent device claim. Furthermore, according to a third and a fourth aspect, the invention provides advantageous uses of a corresponding media combining device with the features of the independent use claims and, according to a fifth aspect, a vehicle with a corresponding fuel cell system with the features of the additional, independent device claim. Further advantages, features and details of the invention result from the dependent claims, the description and the drawings. Features and details that are described in connection with individual aspects of the invention naturally also apply in connection with the other aspects of the invention and vice versa, so that the disclosure of the individual aspects of the invention is or can always be referred to reciprocally.

According to the first aspect, the present invention provides a media combining device for a fuel cell system, with a container or in other words a housing for mixing and/or examining media flows, on which the following elements are arranged, preferably attached, in particular integrated: a line connection for a Exhaust air line for discharging an exhaust air from at least one fuel cell of the fuel cell system, at least one line connection for at least one purge and/or drain line of a purge and/or drain systems of the fuel cell system, a line outlet for discharging media streams from the container, and a fuel sensor for sensing a fuel content in the container.

The fuel cell system can be designed for a vehicle. The fuel cell system can have at least one fuel cell (preferably a fuel cell stack), which can be designed with a stack ventilation system for ventilation of the immediate or immediate vicinity of the stack. Furthermore, the fuel cell system can have a cathode system for providing an oxygen-containing reactant to the at least one fuel cell, wherein the cathode system can have a supply air line for providing supply air to the at least one fuel cell and an exhaust air line for removing exhaust air from the at least one fuel cell. Furthermore, the fuel cell system can have an anode system for providing a fuel-containing reactant to the at least one fuel cell, wherein the anode system can have a purge and/or drain system for flushing the anode path and/or for removing product water from the anode path. Furthermore, the fuel cell system can have a preferably modular tank system with at least one tank (preferably several tanks or bottles per module) for the fuel-containing reactants, which is designed with a tank ventilation system for ventilation of the immediate or immediate vicinity of the tank system can be. The purge and/or drain system may in turn include at least one (combined or dual) purge and/or drain line (which may also be referred to as a purge and/or drain vent line). The stack venting system may include a stack vent line (which in turn may include one stack vent line per stack in a multi-stack modular fuel cell system) to vent the gas or gas mixture used to vent the near or immediate environment of the stack was used from the stack environment. The tank venting system may include a tank vent line (which in turn may include multiple tank vent lines per module in a multi-module modular tank system) to vent the gas or gas mixture used to vent the near or immediate vicinity of the tank system was used to discharge from the tank system environment. Downstream in the exhaust air line of the cathode system, a fuel sensor, for example in the form of a hydrogen sensor, is provided with the aid of the media combining device according to the invention, in particular exclusively one in the entire fuel cell system and in the entire vehicle. Furthermore, it can be provided that the at least one purge and/or drain line, the stack ventilation line and/or the tank ventilation line (preferably all ventilation lines and the at least one purge and/or drain line) are connected to the media combining device according to the invention, in particular fluidly can be connected.

The media combining device can preferably be arranged downstream in the exhaust air line of the cathode system of the fuel cell system. The container of the media combination can be fluidically connected to the exhaust air line, so that the exhaust air from the at least one fuel cell, possibly mixed with the other media streams from the fuel cell system, flows through the media combination device, preferably before it is discharged to the environment.

Downstream in the exhaust air line can be approximately at the end of the exhaust air line, wherein according to the media combining device according to the invention with one, in particular only one in the entire fuel cell system and in the entire vehicle, fuel sensor in the exhaust air line only one silencer can be arranged.

The fuel cell system according to the invention can be designed in the form of a fuel cell stack, a so-called fuel cell stack, with a plurality of stacked repeating units in the form of individual fuel cells, preferably PEM fuel cells. In addition, the fuel cell system according to the invention can be of modular design and have a plurality of fuel cell stacks or fuel cell stacks.

The purge and drain system according to the invention can be combined (a valve and a line) or implemented separately (a purge valve with a purge line and a drain valve with a drain line).

The fuel cell system according to the invention can advantageously be used for mobile applications, such as in motor vehicles, or for stationary applications, such as in generator systems.

The invention provides an optimized fuel cell system and an improved vehicle, including a diagnostic method, which will be discussed in detail below, with a minimum number of fuel sensors, preferably with only one fuel sensor, by means of the media combining device entire fuel cell system and in the entire vehicle.

The essence of the invention lies in the fact that only one fuel sensor can be used for the complete fuel cell system and accordingly for the entire vehicle. According to the invention, the fuel sensor is integrated on or in the media combining device, which is connected to the exhaust line of the fuel cell system. In this case, at least the at least one purge and/or drain line (including a mixed or two separate purge and/or drain line(s)) and possibly all ventilation lines which intentionally and/or unintentionally sources of fuel, in particular hydrogen. Sources of fuel include at least the at least one purge and/or drain line (intended source of fuel mass flow), if applicable the stack vent line (unintended source of fuel leaks, with the stack vent line in turn also including several stack vent lines in a modular fuel cell system with multiple stacks), regardless of whether the at least one fuel cell or fuel cell stack is/are without an additional housing or is/are at least partially arranged in an additional housing, optionally the tank vent line, regardless of whether the tank system is without an additional housing or is at least partly arranged in an additional housing or is modular with several housings and with one or more fuel bottles, with further ventilation systems and/or sources of possible fuel leakage and fuel -Mass flows analogous the aforesaid ventilation lines can be fluidly connected to the media combining device.

An advantage of the invention is that the detection and dilution for all possible (unintended) fuel leaks and/or all possible (intended) fuel mass flows can be carried out at one point, namely in the media combining device. Advantageously, the fuel accumulations can be diluted at least by the exhaust air of the cathode system (and/or by the bypass air of the cathode system). With the aid of the media combining device according to the invention, a diagnostic method and/or a monitoring method with pin pointing, i.e. detection of the source from which the hydrogen leak or the hydrogen mass flow originates, can also be carried out. The connection of the ventilation system for the tank system and the ventilation system for the stack(s) to the media combining device helps to reliably dilute and discharge the fuel that has accumulated in the respective systems.

A further advantage of the invention is that the media combining device can be used to drain water to the environment or to the exhaust air line or to drain water to another functional system of the fuel cell system and/or to a container for further use.

Furthermore, it can be advantageous that the dilution of the drain and/or purge gas and/or fluid mixture is carried out by means of a secondary air mass flow, e.g. B. a fresh air fan of a vehicle interior and / or a separate ventilation fan can be carried out. In this way, decoupling from air compressor operation in the supply air line and/or redundancy for air compressor operation can be created. However, decoupling from the cathode system and/or redundancy can also be created for the ventilation systems of the tank system and/or the stack(s). Advantageously, using the invention also require secondary air systems in the vehicle, such. B. a vehicle interior, a tank system, a trunk system, etc. no separate fuel sensors.

Furthermore, in a media combining device it can be provided that a water outlet for draining off water is arranged on the container. In this way, the media merging device can be used as a water elimination device equipped with a specially designed water outlet. In principle, however, it is also conceivable that the media combining device can be designed without a separate water outlet. In the latter case, the water can be discharged from the fuel cell system through the exhaust air line.

Furthermore, in a media combining device it can be provided that the water outlet is arranged at the lowest point of the container in a usage position of the container. Thus, the water excretion can be promoted.

Furthermore, in a media combining device it can be provided that in a usage position of the container the water outlet is arranged lower than the line outlet for discharging media streams from the container. This can promote the elimination of water from the exhaust air from the fuel cell system. In this way, the line outlet for discharging media streams from the container be provided with an advantageous overflow function.

• - ein Leitungsanschluss für eine Stack-Entlüftungsleitung eines Stack-Belüftungssystems,
• - ein Leitungsanschluss für eine Tank-Entlüftungsleitung eines Tank-Belüftungssystems, und/oder
• - ein Leitungsanschluss für eine Entlüftungsleitung eines weiteren Belüftungssystems,

bspw. versorgt mittels eines Frischluftgebläses eines Fahrzeuginnenraums und/oder eines separaten Belüftungsgebläses.
Das weitere Belüftungssystem kann weitere Bereiche mit Gefahrpotential für Wasserstoff-Ansammlungen belüften, wie z. B. wenn H2-führenden Komponenten wie Leitungen, Ventile, usw. Somit kann die Medienzusammenführungsvorrichtung mit einer erweiterten Funktionalität bereitgestellt werden, um die erfindungsgemäßen Vorteile, wie. z. B. Diagnose einer Leckage, Pin-Pointing sowie Wasserabscheidung, Wasserausleitung und/oder Wasserbereitstellung, auch bei anderen möglichen Belüftungssystemen in einem Brennstoffzellensystem und/oder einem entsprechenden Fahrzeug zu entfalten.As already mentioned above, at least one of the following elements can be arranged on the container:

• - a line connection for a stack ventilation line of a stack ventilation system,
• - a line connection for a tank ventilation line of a tank ventilation system, and/or
• - a line connection for a ventilation line of another ventilation system,

for example supplied by means of a fresh air fan of a vehicle interior and/or a separate ventilation fan.
The further ventilation system can ventilate other areas with a potential risk of hydrogen accumulation, such as e.g. B. when H2-carrying components such as lines, valves, etc. Thus, the media combining device can be provided with an extended functionality to the advantages of the invention, such as. e.g. B. diagnosis of a leak, pin-pointing and water separation, water discharge and / or water supply, also in other possible ventilation systems in a fuel cell system and / or a corresponding vehicle.

Advantageously, the container can have at least one drainage surface. The drainage surface can facilitate the drainage of the water from the container. It is conceivable that the drainage surface is inclined when the container is in a position of use. In addition, it is conceivable that the drainage area is free of connections and/or outlets. In this way, the drainage surface can lead the separated water directly to the intended water outlet or to the line outlet.

Furthermore, it can be advantageous if the container is designed to withstand ice pressure and/or freeze-proof. In this way, the media combining device can also be used in unfavorable weather conditions, for example when the fuel cell system is started from cold.

In addition, it can be advantageous if the container is designed to be explosion-proof. In this way, the risk of explosion in the fuel cell system can be significantly reduced and even localized to the container in order to come to a standstill there in a targeted manner.

• - Umlenkung,
• - Verwirbelung,
• - Drallströmung,
• - Wärmeübertragung, und/oder
• - Abkühlung.

In the case of a media combining device, it can also be advantageous if the line connections and the line outlet are distributed on the container in such a way and/or have such diameters that at least one effect of mixing the media flows is brought about:

• - deflection,
• - swirl,
• - swirl flow,
• - heat transfer, and/or
• - Cooling.

In this way, the mixing of the media streams, which may contain hydrogen, can be promoted within the container.

The line connections on the container that are not used in the fuel cell system can in turn be closed by a blind plug for the sake of simplicity. With the aid of the invention, a standardized media combining device can thus be provided for different topologies of differently designed fuel cell systems.

According to the second aspect, the invention provides a fuel cell system with a media combining device, which can be embodied as described above and which can be arranged downstream in an exhaust air line of a cathode system. The exhaust air line can be fluidly connected to the container of the media combining device. In this case, the media combining device can preferably be arranged at the end of the exhaust air line, with only one muffler being able to be arranged in the exhaust air line according to the media combining device according to the invention.

Furthermore, it can be provided in a fuel cell system that the stack ventilation system and/or the tank ventilation system have at least one ventilation line (meaning a ventilation supply line). The at least one ventilation line can lead from a fresh air source, e.g. supply air from the cathode system, a fresh air fan of a vehicle interior and/or a separate ventilation fan, to the respective system, e.g. into the respective housing.

Furthermore, it can be provided in a fuel cell system that the at least one ventilation line is connected to the air supply line of the cathode system in order to draw the air supply from the air supply line of the cathode system to ventilate the at least one fuel cell or the stack(s) as part of the stack ventilation system, to dilute a purge gas from the anode system and/or to ventilate the tank system. It is conceivable that the at least one ventilation line in front of a Humidifier can be connected to the supply air line of the cathode system. A dry supply air can thus be provided from the supply air line for diluting the purge gas from the anode system of the fuel cell system and/or for venting the stack and/or tank system. It is also conceivable that the at least one aeration line can be connected to the air supply line of the cathode system after a humidifier. A humidified supply air can thus be provided from the supply air line to dilute the purge gas of the anode of the fuel cell system and/or to ventilate the stack and/or tank system. It is also conceivable that the at least one ventilation line is connected to the air supply line of the cathode system upstream of an air supply cooler. A heated supply air can thus be provided from the supply air line for diluting the purge gas from the anode system of the fuel cell system and/or for venting the stack and/or tank system.

Furthermore, it can be provided in a fuel cell system that the at least one ventilation line is connected to a fresh air fan of a vehicle interior in order to supply fresh air and/or cabin air for ventilating the at least one fuel cell or the stack(s) as part of the stack ventilation system , to dilute a purge gas from the anode system and/or to ventilate the tank system. Thus, an additional ventilation source can be provided. This can be advantageous when the compressor in the cathode system is switched off or to continue operating the compressor at part load (if the requested stack air mass flow would not be sufficient for dilution).

In addition, it can be provided in a fuel cell system that the at least one ventilation line is connected to a separate ventilation fan in order to emit fresh air to ventilate the at least one fuel cell or the stack(s) as part of the stack ventilation system, to dilute a purge gas to provide the anode system and/or to ventilate the tank system. This too can provide an additional source of ventilation to supplement or replace the compressor.

The invention provides according to the third aspect: using a media combining device, which can be embodied as described above, in a method for diagnosing a fuel leak, for determining a source of a fuel leak, for checking a fuel mass flow and/or for diluting a fuel mass flow in a fuel cell system. A method for diagnosing a fuel leak, for determining a source of a fuel leak, for checking a fuel mass flow and/or for diluting a fuel mass flow in a fuel cell system can thus be carried out with the aid of the media combining device according to the invention. The method can in turn be used to achieve the same advantages that were described above in connection with the fuel cell system according to the invention. Reference is made in full to these advantages here.

• D4) Überwachen von Messwerten des Brennstoffsensors im laufenden Betrieb des Brennstoffzellensystems.

The invention can advantageously provide at least one following step in a method for diagnosing a fuel leak, for determining a source of a fuel leak, for checking a fuel mass flow and/or for diluting a fuel mass flow in a fuel cell system:

• D4) monitoring of measured values of the fuel sensor during ongoing operation of the fuel cell system.

The diagnosis in step D4) can advantageously be carried out during normal operation of the fuel cell system, without much effort and with little computing power. The measured value or the measured values or the measurement signal of the fuel sensor can be compared to a threshold or a plurality of thresholds. The measured value or the measured values or the measured signal of the fuel sensor can advantageously be evaluated over time in order to detect increases in the fuel content and the leaks at an early stage. If the measured value or the measured values or the measured signal of the fuel sensor is sufficiently low, no or, depending on the threshold value, initially no more precise diagnosis is necessary. However, if the values are above an applicable limit, further diagnoses D1), D2), D3) can be carried out.

In a method, the invention can also provide for the stack ventilation system and the tank ventilation system to be active in step D4), with the purge and/or drain system being inactive (i.e. not currently activated or closed). The normal operation of the fuel cell system can thus be mapped.

Furthermore, in a method, the invention can provide that in step D4) at least one or more threshold values for a fuel concentration are monitored. In this way, applicable limits can be determined in order to initiate a respective action. A low limit that is not exceeded can be a sign of "everything is fine". From the low For example, a checking action can be initiated at the limit, e.g. B. reading the fuel cell sensor more frequently in step D4), observing the increase in fuel content and/or initiating further diagnostics D1), D2), D3). A higher limit can, for example, initiate a warning action, e.g. B. Requesting the vehicle to stop, requesting the vehicle occupants to leave the vehicle, warning other road users, etc.

Step D4) can advantageously be carried out periodically. Thus, the fuel cell system and/or vehicle can be checked prophylactically for fuel leaks.

It can also be advantageous to inform the user about the results of the method according to the invention, for example via a display unit, e.g. B. in a dashboard of the vehicle, in a head-up display, etc.

• D1) Betreiben des Purge- und/oder Drainsystems, wobei das Stack-Belüftungssystem und das Tank-Belüftungssystem inaktiv (d. h. temporär deaktiviert, geschlossen oder nicht im Betrieb) sind,

und/oder D2) Betreiben des Stack-Belüftungssystems, wobei das Purge- und/oder Drainsystem und das Tank-Belüftungssystem temporär inaktiv, geschlossen oder nicht im Betrieb sind,
und/oder D3) Betreiben des Tank-Belüftungssystems, wobei das Purge- und/oder Drainsystem und das Stack-Belüftungssystem inaktiv sind,
wobei insbesondere die Schritte D1), D2) und/oder D3) periodisch durchgeführt werden. Somit kann ein Diagnose-Verfahren mit Pin-Pointing, d. h. Detektion aus welcher Quelle die Wasserstoff-Leckage bzw. der Wasserstoff-Massenstrom stammt, durchgeführt werden. Dazu werden die jeweiligen Pfade der Belüftungssysteme so geschaltet, dass kurzzeitig nur eine mögliche Quelle für eine Brennstoff-Leckage bzw. Wasserstoff-Massenstrom detektiert wird. Zwischen den Schritten D1), D2) und D3) können bestimmte Wartezeiten und/oder Mittelungen, Empfehlungen an den Benutzer, etc. eingerichtet werden.Furthermore, a method can have at least one of the following steps:

• D1) Operating the purge and/or drain system, with the stack ventilation system and the tank ventilation system being inactive (ie temporarily deactivated, closed or not in operation),

and/or D2) operating the stack ventilation system, with the purge and/or drain system and the tank ventilation system being temporarily inactive, closed or not in operation,
and/or D3) operating the tank ventilation system, with the purge and/or drain system and the stack ventilation system being inactive,
in particular steps D1), D2) and/or D3) being carried out periodically. A diagnostic method with pin pointing, ie detection of the source from which the hydrogen leak or the hydrogen mass flow originates, can thus be carried out. For this purpose, the respective paths of the ventilation systems are switched in such a way that only one possible source of a fuel leak or hydrogen mass flow is detected for a short time. Certain waiting times and/or averaging, recommendations to the user, etc. can be set up between steps D1), D2) and D3).

In this way, the respective individual values for possible sources of fuel leaks or hydrogen mass flow can be determined. It is also conceivable that the values are compared with one another, with each other or in combination with one another in order to check the plausibility of the results of the method (e.g. value in D4 = value in D2+value in D3?). The diagnoses can also be used prophylactically at periodic intervals be performed.

In addition, a method can have at least one of the following steps: D5) Monitoring of measured values of the fuel sensor in an unventilated operation of the fuel cell system, with the purge and/or drain system, the stack ventilation system and the tank ventilation system being inactive. Thus, the invention can be used in an advantageous manner to calibrate the fuel sensor. In addition, the invention can be used in an advantageous manner to carry out an open/close diagnosis of a purge valve.

• D6) Überwachen von Messwerten des Brennstoffsensors in einem voll belüfteten Betrieb des Brennstoffzellensystems, wobei das Purge- und/oder Drainsystem,
• das Stack-Belüftungssystem und das Tank-Belüftungssystem aktiv sind. Auf diese Weise können alle Belüftungssysteme im Vollbetrieb überprüft werden.
• Dies kann bspw. beim Abstellen des Fahrzeuges oder kurz vor dem Starten des Fahrzeuges vorteilhaft sein, um bspw. schnell zu überprüfen, ob alles in Ordnung ist, und/oder um zu erfahren, ob eine zusätzliche Diagnose D1), D2) und/oder D3) erforderlich ist, und/oder um eine Plausibitätsmessung, z. B. für die Schritte D1), D2) und/oder D3), zu erhalten.

In addition, a method may include at least one of the following steps:

• D6) Monitoring measured values of the fuel sensor in a fully aerated operation of the fuel cell system, the purge and/or drain system,
• the stack ventilation system and the tank ventilation system are active. In this way, all ventilation systems can be checked in full operation.
• This can be advantageous, for example, when parking the vehicle or just before starting the vehicle, for example to quickly check whether everything is OK and/or to find out whether an additional diagnosis D1), D2) and/or D3) is required and/or a plausibility measurement, e.g. g. for steps D1), D2) and/or D3).

Advantageously, it is also possible that the results of steps D1), D2), D3), D4), D5) and/or D6) are recorded in a memory of the fuel cell system or in an online memory. In this way, characteristic reference values can be created for the respective system.

Furthermore, it can be advantageous if the results of steps D1), D2), D3), D4), D5) and / or D6) over a lifetime of the fuel cell system or over a load profile, in particular after a tank change, tank filling, after a pressure change , after a change in temperature, after a certain number of starts/stops, after certain services have been performed (certain fixed threshold values are possible here), whenever the vehicle is parked for a long time, e.g. overnight or in an airport parking lot, etc., in a control unit of the fuel cell system or in an online server.

Furthermore, it can be advantageous if the at least one or more fuel cell systems are monitored according to a method described above to the aging of at least to evaluate one or more fuel cell systems or to monitor a vehicle or a vehicle fleet.

The steps of the method according to the invention can be carried out in the given order or in a modified order. Advantageously, the steps of the method according to the invention can be carried out simultaneously and/or repeatedly in order to enable a fluent process.

According to the fourth aspect, the invention provides: using a media combining device, which can be designed as described above, for draining water to an environment and/or for draining water to a functional system and/or to a storage system of a fuel cell system.

According to the fifth aspect, the invention provides a vehicle with a fuel cell system, which can be configured as described above. With the aid of the vehicle according to the invention, the same advantages can be achieved that were described above in connection with the fuel cell system according to the invention and/or with the media combining device according to the invention. Reference is made in full to these advantages here.

character list

• 1 eine schematische Darstellung eines Brennstoffzellensystems im Sinne der Erfindung,
• 2 eine schematische Darstellung eines Diagnoseverfahrens im Sinne der Erfindung,
• 3 eine schematische Darstellung einer Medienzusammenführungsvorrichtung im Sinne der Erfindung,
• 4 eine schematische Darstellung einer weiteren möglichen Medienzusammenführungsvorrichtung im Sinne der Erfindung.

The invention and its developments as well as its advantages are explained in more detail below with reference to drawings. They each show schematically:

• 1 a schematic representation of a fuel cell system according to the invention,
• 2 a schematic representation of a diagnostic method within the meaning of the invention,
• 3 a schematic representation of a media merging device within the meaning of the invention,
• 4 a schematic representation of another possible media combining device within the meaning of the invention.

In the different figures, the same parts of the invention are always provided with the same reference numerals, which is why these i. i.e. R. only be described once.

the 1 shows a fuel cell system 100 according to the invention, which can be used, for example, as a drive energy source in a vehicle 1, preferably in an electric vehicle and/or a hybrid vehicle.

The fuel cell system 100 can have at least one fuel cell 101 or at least one stack of multiple fuel cells 101 that are combined to form a fuel cell stack, which can be implemented with a stack ventilation system Q2. The fuel cell 101 or the fuel cell stack or stack can have fuel leakage to the outside, since the many fuel cells 101 are designed with many seals that are subject to various aging mechanisms caused by media, mechanical stresses, temperature changes, pressure changes, etc. The fuel cell 101 or the fuel cell stack or stack can at least z. T. in a housing 102 (at least in the upper area) are included, so that ventilation can be done in a targeted manner. Escaping fuel, in particular hydrogen, can collect in an upper area from which a stack ventilation line L2 of the stack ventilation system Q2 can lead. The stack ventilation line L2 of the stack ventilation system Q2 can advantageously be introduced into a media combining device M according to the invention with a fuel sensor S, in particular in the form of a hydrogen sensor. The exhaust air from the exhaust air line 12 of the cathode system 10 can dilute any fuel that may have accumulated.

The inventive media merging device M is described below with reference to 3 and 4 described in detail.

For ventilation of the fuel cell 101 or the fuel cell stack, the first supplier A1 can be the supply air from the supply air line 11 of the cathode system 10 or from another supplier A2, A3, such as e.g. B. fresh air fan IN a vehicle interior and / or a separate ventilation fan BG can be used. The supply air can, for example, via a connecting line, which can optionally but advantageously contain a throttle VQ2, VQ3 and/or a controllable valve VSQ2, VSQ3, to the housing 102 of the at least one fuel cell 101 or the at least one fuel cell stack, preferably in the lower area to be initiated. Various suppliers (such as the supply air line 11, a fresh air fan IN of a vehicle interior and/or a separate ventilation fan BG) for the ventilation lines A1, A2, A3 can be used to supply the air mass flow, as described in detail below becomes.

As already mentioned above, the fuel cell system 100 has a cathode system 10 for providing an oxygen-containing reactant ten to the at least one fuel cell 101 or to the at least one fuel cell stack, with the cathode system 10 having an air supply line 11 for providing air supply to the at least one fuel cell 101 and an exhaust air line 12 for removing exhaust air from the at least one fuel cell 101. The system topology according to the invention provides only one, in particular exclusively one, fuel sensor S in the fuel cell system 101 and in the entire vehicle 1, which in turn is arranged, in particular fastened and/or integrated, in or on the media combining device M according to the invention. Various sources of fuel leaks or fuel mass flows are fed into the media merging device M through corresponding ventilation systems Q1, Q2, Q3.

The cathode system 10 is in the 1 drawn as an example. The supply air can z. B. from the environment U and filtered according to the requirements of the fuel cell 101 using an air filter AF. Different system topologies, with/without an intake air cooler IC, with/without a turbine in the exhaust air line 12, with/without a bypass line with a bypass valve BV, with/without a humidifier H, with/without shut-off valves SV1, SV2, with an on or multi-stage compression, with a single-flow or multi-flow compressor V, with one or two-shaft systems, with/without water injection, etc. are possible.

Furthermore, fuel cell system 100 has an anode system 20 for providing a fuel-containing reactant to the at least one fuel cell 101 or to the at least one fuel cell stack, with anode system 20 having a purge and/or drain system Q1 for flushing the anode path of anode system 20 and/or for Discharging a product water from the anode path of the anode system 20 has. The at least one purge and/or drain line L1 is advantageously introduced into the media combining device M in order to mix and/or dilute the fluid mixture from the at least one purge and/or drain line L1 with other media flows.

The purge process can advantageously take place not only when the cathode system 10 provides sufficient air mass flow/air volume flow, but also when this is not the case. For this purpose, using the fuel cell system 100 in addition to the supply air from the supply air line 11 other suppliers A2, A3, such. B. fresh air fan IN a vehicle interior and / or a separate ventilation fan BG can be used.

Furthermore, the fuel cell system 100 has a preferably modular tank system 30 with at least one tank T (preferably several tanks T or bottles per module) for the fuel-containing reactant, which can be designed with a tank ventilation system Q3. The tank system 30 can be arranged, for example, in the rear area of the vehicle 1 (eg in a trunk) or in an underbody of the vehicle (eg below the fuel cell stack or below the passenger compartment). Due to the modular design of the tank system 30, the distance between the tank system 30 and the stack and/or the cathode system 10 is reduced and connections between these systems can be implemented more easily. Advantageously, the individual tanks T can be enclosed in a module, e.g. by several modules in the tank system 30, by means of (each) a tank housing 31, which can form part of the tank ventilation system Q3. The tank housing 31 can in turn have a tank ventilation line L3.

For the ventilation of the tank system 30, the first supplier A1 can be the supply air from the supply air line 11 of the cathode system 10 and/or the fresh air from another supplier A2, A3, e.g. B. fresh air fan IN a vehicle interior and / or a separate ventilation fan BG can be used.

The supply air for the ventilation is supplied by the first supplier A1 via a ventilation line A1, which is branched off from the supply air line 11 of the cathode system 10, e.g. before the humidifier H (ventilation line A1.1), after the humidifier H (ventilation line A1.2) or in front of the supply air cooler IC (ventilation line A1.3).

According to the invention, the purge and/or drain system Q1 has at least one (combined or double) purge and/or drain line L1. The stack ventilation system Q2 has (at least) one stack ventilation line L2. The tank ventilation system Q3 has (at least) one tank ventilation line L3. At the end of or downstream in the exhaust air line 12 of the cathode system 10, the media combining device M according to the invention is arranged with one, in particular exclusively one in the entire fuel cell system 100 and in the entire vehicle 1, fuel sensor S, e.g. in the form of a hydrogen sensor. According to the invention, the at least one purge and/or drain line L1, if applicable the stack ventilation line L2 and/or the tank ventilation line L3, lead into the media combining device M according to the invention (preferably all three lines L1, L2, L3), as required by the 1 e.g. shows.

Within the scope of the invention, only one fuel sensor S can be used with the aid of the media combining device M according to the invention for the complete fuel cell system 100 and for the entire vehicle 1 . In this case, all lines L1, L2, L3, which can be sources of fuel, in particular hydrogen, can be fluidly connected to the media combining device M. In the 1 are, for example, the at least one purge and/or drain line L1, the stack ventilation line L2, regardless of whether the at least one fuel cell 101 or the at least one fuel cell stack is/are without an additional housing or at least z. T. is / are arranged in an additional housing 102, and the tank vent line L3, regardless of whether the tank system 30 is without an additional housing or at least z. T. is arranged in an additional housing 31 shown. However, other sources Q4 for possible fuel leaks are also conceivable within the scope of the invention, which can also be fluidically connected to the media combining device M like the ventilation lines L1, L2, L3 mentioned.

Thus, with the aid of the media combining device M according to the invention, all possible fuel leaks can be detected at one point in the fuel cell system 100 . The accumulations of fuel can advantageously be diluted at least by the exhaust air of the cathode system 10 and/or by the air of the bypass of the cathode system 10 . Additional sources of ventilation are described below

With the aid of the media combining device M according to the invention, a diagnostic method and/or checking method with pin pointing, ie detection of the source from which the hydrogen leakage or the hydrogen mass flow originates, can also be carried out, as is shown in FIG 2 is shown.

By connecting the tank ventilation system Q3 and the stack ventilation system Q2 to the media combining device M, the fuel accumulated in the respective systems can be reliably discharged and diluted.

Provision can advantageously be made for the purge gas to be diluted by means of a secondary air mass flow A2, A3, e.g. B. a fresh air fan IN a vehicle interior and / or a separate ventilation fan BG can be performed. In this way, decoupling from the air compressor operation in the supply air line 11 and redundancy can be created.

However, decoupling from the cathode system 10 and redundancy can also be created for the ventilation systems Q2, Q3 of the tank system 30 and/or the stack.

the 2 1 schematically shows a possible method for diagnosing a fuel leak and/or a fuel mass flow in a fuel cell system 100 for a vehicle 1, which can be implemented as described above. The media combining device M according to the invention can advantageously be used to carry out the method.

• D4) Überwachen von Messwerten des Brennstoffsensors S im laufenden Betrieb („normal operation“) des Brennstoffzellensystems 100.

The method can have at least one of the following steps:

• D4) Monitoring of measured values of the fuel sensor S during operation ("normal operation") of the fuel cell system 100.

The diagnosis in step D4) can compare the measured value or the measured values or the measured signal of the fuel sensor S with a threshold value or with a plurality of threshold values. The measured value or the measured values or the measured signal of the fuel sensor S can advantageously be evaluated over time in order to be able to detect increases in the fuel content and the leaks at an early stage. If the measured value or the measured values or the measured signal of the fuel sensor is sufficiently low, no or, depending on the threshold value, initially no more precise diagnosis is necessary. However, if the values are above an applicable limit, further diagnoses D1), D2), D3) can be carried out.

A low limit or a first threshold value that is not exceeded in step D4) can be a sign of “everything is OK”. From the low limit upwards, for example, a checking action can be initiated, e.g. B. reading the fuel cell sensor S more frequently in step D4), observing the increase in fuel content and/or initiating further diagnoses D1), D2), D3). A higher limit or a second threshold value can, for example, result in a warning action, e.g. B. Requesting the driver to stop the vehicle 1, requesting the vehicle occupants to leave the vehicle 1, warning other road users, etc.

It can also be advantageous to inform the user of the vehicle 1 about the results of the method according to the invention, for example via a display unit, e.g. B. in a dashboard of the vehicle 1, in a head-up display o. Ä.

• D1) Betreiben des Purge- und/oder Drainsystems Q1, wobei das Stack-Belüftungssystem Q2 und das Tank-Belüftungssystem Q3 inaktiv (d. h. deaktiviert oder nicht im Betrieb) sind,

Above a certain threshold, the following steps can be taken:

• D1) Operating the purge and/or drain system Q1, with the stack ventilation system Q2 and the tank ventilation system Q3 being inactive (ie deactivated or not in operation),

D2) operating the stack ventilation system, with the purge and/or drain system and the tank ventilation system being inactive, and/or D3) operating the tank ventilation system with the purge and/or drain system and the stack ventilation system being inactive .

Steps D1), D2) and/or D3) can also be carried out periodically. This makes it possible to detect the source from which the fuel leakage or the fuel mass flow originates.

For this purpose, the respective paths Q1, Q2, Q3 of the possible sources are switched in such a way that only one possible source for a fuel leak or fuel mass flow is briefly detected.

Specific waiting times and/or averaging, recommendations to the user of the vehicle 1 can be set up between steps D1), D2) and D3).

It is also conceivable that the measured values in steps D1) to D4) are compared with one another, with one another or in combination with one another in order to check the plausibility of the results of the method (e.g. value in D4 = value in D2+value in D3? )

• D5) Überwachen von Messwerten des Brennstoffsensors S in einem unbelüfteten Betrieb („all closed“) des Brennstoffzellensystems 100, wobei das Purge- und/oder Drainsystem Q1, das Stack-Belüftungssystem Q2 und das Tank-Belüftungssystem Q3 alle ausgeschaltet sind. Somit kann der Brennstoffsensor S1 geeicht bzw. kalibriert werden. Auch kann somit eine Offen/Zu-Diagnose eines Purge-Ventils PVD durchgeführt werden.

In addition, the method can have at least one of the following steps:

• D5) Monitoring of readings of the fuel sensor S in an unventilated operation (“all closed”) of the fuel cell system 100, wherein the purge and/or drain system Q1, the stack ventilation system Q2 and the tank ventilation system Q3 are all switched off. The fuel sensor S1 can thus be gauged or calibrated. An open/closed diagnosis of a purge valve PVD can thus also be carried out.

• D6) Überwachen von Messwerten des Brennstoffsensors S in einem voll belüfteten Betrieb („all open“) des Brennstoffzellensystems 100, wobei das Purge- und/oder Drainsystem Q1, das Stack-Belüftungssystem Q2 und das Tank-Belüftungssystem Q3 aktiv sind. Dieser Schritt D6) kann bspw. beim Abstellen des Fahrzeuges 1 oder kurz vor dem Starten des Fahrzeuges 1 durchgeführt werden, um bspw. schnell zu überprüfen, ob alles in Ordnung ist, und/oder um zu erfahren, ob eine zusätzliche Diagnose D1), D2) und/oder D3) erforderlich ist, und/oder um eine Referenzmessung für die Schritte D1), D2) und/oder D3) zu erhalten.

In addition, the invention can provide that the method has at least one of the following steps:

• D6) Monitoring of measured values of the fuel sensor S in a fully aerated operation (“all open”) of the fuel cell system 100, with the purge and/or drain system Q1, the stack ventilation system Q2 and the tank ventilation system Q3 being active. This step D6) can be carried out, for example, when the vehicle 1 is parked or shortly before the vehicle 1 is started, in order, for example, to quickly check whether everything is in order and/or to find out whether an additional diagnosis D1), D2) and/or D3) and/or to obtain a reference measurement for steps D1), D2) and/or D3).

It is also conceivable that the measured values in steps D1) to D6) are compared with one another, with one another or in combination with one another in order to check the results of the method for plausibility (e.g. value in D1 <= value in D6?)

It is advantageously possible within the scope of the invention for the results of steps D1), D2), D3), D4), D5) and/or D6) to be recorded in a memory of the fuel cell system 101 or in an online memory.

It is also conceivable that the results of steps D1), D2), D3), D4), D5) and / or D6) over a lifetime of the fuel cell system 100 or over a load profile, in particular after a tank change, tank filling, after a pressure change , after a change in temperature, after a certain number of starts/stops, after certain services have been rendered (several threshold values, e.g. for the mileage of the vehicle 1 or for the kilowatts of electrical output of the fuel cell system 100 are possible), whenever the vehicle 1 is parked for a long time, for example overnight or in an airport parking lot etc., in a control unit of the fuel cell system 100 or in an online server.

Advantageously, the at least one or more fuel cell systems 100 can be monitored according to a method described above in order to evaluate the aging of the at least one or more fuel cell systems 100 or to monitor a vehicle or a vehicle fleet. In this case, only one media combining device M within the meaning of the invention can be provided for the at least one or more fuel cell systems 100 .

the 3 and 4 each show a possible embodiment of a media merging device M according to the invention. The media merging device M has a container MB, which can also be referred to as a housing and can be designed with or without a storage function for water H2O. The container MB is designed for mixing and/or examining media flows.

The following elements are arranged on the container MB, preferably attached, in particular integrated: a line connection M1 for an exhaust air line 12 for discharging an exhaust air from the at least one fuel cell 101 of the fuel cell system 100, at least one common or two separate line connections MQ1 for at least one purge and /or drain line L1 of a purge and/or drain system Q1 of the fuel cell system 100, a line outlet M2 for discharging media streams from the container MB, and a fuel sensor S for sensing a fuel content in the container MB. The fuel sensor S may preferably be arranged in an upper part of the canister MB (when the canister MB is positioned in a use position). In the upper part of the container MB, the media flows are well mixed, so that the fuel content can be detected better.

In the embodiment of 3 A water outlet MW for discharging water H2O can be arranged on the container MB, preferably attached, in particular integrated.

As the 4 shows, it is also conceivable that the media combining device M can be designed without a separate water outlet MW. In the embodiment of 4 the water H2O can be removed from the fuel cell system 100 through the exhaust air line 12 .

Like it the 3 11, the water outlet MW may be located at the deepest point of the container MB (the deepest point can be determined when the container MB is positioned in a use position).

Furthermore, the 3 that the water outlet MW can be arranged deeper than the line outlet M2 for discharging media streams from the container MB (the deepest point can be determined when the container MB is positioned in a use position). The line outlet M2 can thus fulfill an overflow function.

• - ein Leitungsanschluss MQ2 für eine Stack-Entlüftungsleitung L2 eines Stack-Belüftungssystems Q2,
• - ein Leitungsanschluss MQ3 für eine Tank-Entlüftungsleitung L3 eines Tank-Belüftungssystems Q3, und/oder
• - ein Leitungsanschluss MQ4 für eine Entlüftungsleitung L4 eines weiteren Belüftungssystems Q4,

bspw. versorgt mittels eines Frischluftgebläses IN eines Fahrzeuginnenraums und/oder eines separaten Belüftungsgebläses BG.Like it the 3 and 4 also show that at least one of the following elements can be arranged on the container MB:

• - a line connection MQ2 for a stack ventilation line L2 of a stack ventilation system Q2,
• - A line connection MQ3 for a tank ventilation line L3 of a tank ventilation system Q3, and/or
• - a line connection MQ4 for a ventilation line L4 of another ventilation system Q4,

for example supplied by means of a fresh air fan IN of a vehicle interior and/or a separate ventilation fan BG.

In this way, the advantages of the invention, such as. e.g. B. diagnosis of a leak, pin pointing and water discharge and / or water supply, can also be achieved with other possible ventilation system in the fuel cell system 100.

Like it the 3 and 4 also show that the container MB can have at least one drainage surface MA. The outflow of the water H2O can be favored by the outflow area MA. In the illustrated position of use of the container MB, the drainage surface MA is inclined. No connections and/or outlets are provided on the drainage area MA, so that the water H2O can drain undisturbed to the water outlet MW provided or to the line outlet M2.

The container MB can preferably be designed to be ice-pressure-resistant and/or freeze-proof. In addition, it can be advantageous if the container MB is designed to be explosion-proof.

• - Umlenkung,
• - Verwirbelung,
• - Drallströmung,
• - Wärmeübertragung, und/oder
• - Abkühlung.

A media combining device M can advantageously be designed in such a way that the line connections M1, MQ1, MQ2, MQ3, MQ4 and the line outlet M2 can be distributed on the container MB and/or designed with such diameters that at least one effect promotes mixing of the media flows can be:

• - deflection,
• - swirl,
• - swirl flow,
• - heat transfer, and/or
• - Cooling.

If in some system topologies some systems Q2, Q3, Q4 are not provided or are not used, the line connections M1, MQ1, MQ2, MQ3, MQ4 on the container MB can remain closed by a blind plug. A standardized media combining device M for different topologies of the fuel cell system 100 can advantageously be provided with the aid of the invention.

According to the second aspect, the invention provides a fuel cell system with a media combining device M ready, which can be designed as described above and which can be arranged downstream in an exhaust air line 12 of a cathode system 10. In this case, the exhaust air line 12 can run through the container MB of the media combining device M. The media combining device M can preferably be arranged at the end of the exhaust air line 12 , it being possible for only one silencer to be arranged in the exhaust air line 12 according to the media combining device M according to the invention.

A vehicle 1 with a corresponding fuel cell system 100, in which a media combining device M according to the invention is provided downstream in the exhaust air line 12 of the cathode system 10, also represents an aspect of the invention.

The above description of the figures describes the present invention exclusively within the framework of examples. It goes without saying that individual features of the embodiments can be freely combined with one another, insofar as this makes technical sense, without departing from the scope of the invention.

Claims (10)

Media combining device (M) for a fuel cell system (100), comprising: a container (MB) for mixing and/or examining media flows, on which the following elements are arranged: - a line connection (M1) for an exhaust air line (12) for discharging an exhaust air from at least one fuel cell (101) of the fuel cell system (100), - at least one line connection (MQ1) for at least one purge and/or drain line (L1) of a purge and/or drain system (Q1) of the fuel cell system (100), - A line outlet (M2) for discharging media streams from the container (MB), and - a fuel sensor (S) for sensing a fuel content in the container (MB). Media merging device (M) according to claim 1 , characterized in that a water outlet (MW) for discharging water is arranged on the container (MB). Media merging device (M) according to claim 2 , characterized in that in a position of use of the container (MB) the water outlet (MW) is arranged at the lowest point of the container (MB) and/or that in a position of use of the container (MB) the water outlet (MW) is lower than the Line outlet (M2) for discharging media streams from the container (MB) is arranged, and / or that the line outlet (M2) for discharging media streams from the container (MB) is designed with an overflow function. Media combining device (M) according to one of the preceding claims, characterized in that at least one of the following elements is arranged on the container (MB): - a line connection (MQ2) for a stack ventilation line (L2) of a stack ventilation system (Q2), - a line connection (MQ3) for a tank ventilation line (L3) of a tank ventilation system (Q3), and/or - a line connection (MQ4) for a ventilation line (L4) of a further ventilation system (Q4), e.g. supplied by means of a fresh air blower ( IN) of a vehicle interior and/or a separate ventilation fan (BG). Media combining device (M) according to one of the preceding claims, characterized in that the container (MB) has at least one drainage surface (MA), in particular in a position of use of the container (MB) the drainage surface (MA) can be positioned inclined, with preferably the drainage surface (MA) is free of connections and/or outlets, and/or that the container (MB) is designed to be ice pressure-resistant and/or freeze-proof. Media combining device (M) according to one of the preceding claims, characterized in that the line connections (M1, MQ1, MQ2, MQ3, MQ4) and the line outlet (M2) are distributed on the container (MB) and/or have such diameters that at least an effect for mixing the media flows is brought about: - deflection, - turbulence, - swirl flow, - heat transfer, and/or - cooling, and/or that the line connections (M1, MQ1, MQ2, MQ3, MQ4) on the container (MB) through are each closed a blind plug that are not used in the fuel cell system (100). Fuel cell system (100) with a media combining device (M) according to any one of the preceding claims, wherein the media combining device (M) downstream in an exhaust air line (12) of a cathode system tems (10) of the fuel cell system (100) is arranged. Use of a media combining device (M) according to one of the preceding claims in a method for diagnosing a fuel leak, for determining a source of a fuel leak, for checking a fuel mass flow and/or for diluting a fuel mass flow in a fuel cell system (100 ) according to the preceding claim. Use of a media combining device (M) according to one of the preceding claims for draining water to an environment and/or for draining water to a functional system and/or to a storage system of a fuel cell system (100). claim 7 . Vehicle (1) with a fuel cell system (100). claim 7 .

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