Method for controlling a fuel cell device, control program, computer-readable data carrier and control device, fuel cell device and vehicle comprising a fuel cell device

Abstract

There is provided: a method for operating a fuel cell device, in particular a fuel cell device of a fuel cell system of a vehicle such as an aircraft; a control program for controlling the fuel cell device; a computer readable data carrier; a control device; a fuel cell device; the invention relates to a method for controlling a fuel cell device, and a vehicle, in particular an aircraft, comprising the fuel cell device, in which the method comprises the steps of: acquiring at least one reaction temperature value representative of a reaction temperature at which a fuel, such as hydrogen, is converted within the fuel cell device; acquiring at least one system temperature value representative of a system temperature of the fuel cell device; monitoring a temperature difference between the at least one reaction temperature value and the at least one system temperature value; and initiating at least one fuel starvation damage countermeasure to avoid a local fuel starvation state of the fuel cell device if the temperature difference indicates a fuel starvation likelihood.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of hydrogen fuel systems for vehicles, in particular for aircraft. In particular, the present disclosure relates to a method for operating a fuel cell device, in particular a fuel cell device of a fuel cell system of a vehicle, such as an aircraft; a control program for controlling a fuel cell device, in particular a fuel cell device of a fuel cell system of a vehicle, such as an aircraft; a computer-readable data carrier; a control device for controlling an energy conversion device of a vehicle, such as an aircraft; a fuel cell device for a vehicle, in particular for an aircraft; and a vehicle, in particular an aircraft. BACKGROUND

[0002] Alternative fuels are currently emerging to replace fossil fuels in order to avoid their impact on the environment. Vehicles, such as hydrogen-powered fuel cell aircraft, can use hydrogen to power their propulsion and also for power generation, as alternative fuels can replace conventional fuels, such as kerosene, for operating any fuel conversion device on board of an aircraft, including propulsion units and auxiliary power units (APUs). Converting hydrogen gas does not lead to the formation of carbon dioxide and other carbon-hydrogen compound related emissions and is therefore seen as a way to achieve environmentally friendly and sustainable aviation.

[0003] However, operating a hydrogen-based aircraft involves new challenges in handling the fuel cell system for converting hydrogen into electrical energy. One area of concern in fuel cell systems is possible fuel starvation, where hydrogen is not sufficiently present at the fuel cell membrane in the required amount, thus leading to a local sub-stoichiometric state at the anode. Detecting such a state to avoid damage to the fuel cell membrane poses a challenge, for example by Xiangyang Zhou, Hao Ji, Bing Li and Cunman Zhang in “High-Repetitive Reversal Tolerant Performance of Proton-Exchange Membrane Fuel Cell by Designing a Suitable Anode”, ACS Omega, 2020, 5(17), pp 10099-10105, DOI: 10.1021 / acsomega.0c00638; Huicui Chen, Xin Zhao, Tong Zhang, Pucheng Pei in “The reactant starvation of the proton exchange membrane fuel cells for vehicular applications: A review”, Energy Conversion and Management, Volume 182, 2019, pp 282-298, ISSN 0196-8904, https: / / doi.org / 10.1016 / j.enconman.2018.12.049; or Obermaier, M., Rauber, M., Bauer, A., Lochner, T., Du, F., and Scheu, C. (2020) “Local Fuel Starvation Degradation of an Automotive PEMFC Full Size Stack”, Fuel Cells, Volume 20, pp 394-402, https: / / doi.org / 10.1002 / fuce.201900180.

[0004] The challenges and problems described and addressed by the prior art partly stem from the fact that the operating conditions of fuel cell systems are usually developed to set a certain proportion of liquid and gaseous product water that is generated by the conversion of hydrogen and oxygen to generate electricity and heat as by-products. Usually, these operating conditions are simulated and tested under steady-state conditions. The results of both simulation and testing are various polarization curves.

[0005] However, such steady-state assumption based development only partly reflects the behavior of fuel cells under field dynamic conditions. This has the consequence that the developed operating conditions do not set the operating conditions under which they actually occur. This can lead to, for example, water accumulation on the anode side and cause local fuel starvation, which can eventually lead to complete cell stack loss if no countermeasures are taken. In addition, even when a cell voltage monitoring unit is available, local fuel starvation is not easily detected.

[0006] CN 115084593 A, for example, relates to a fuel cell fault diagnosis method based on nonlinear impedance spectrum and comprises the following steps: designing different types and different degrees of fault conditions, applying AC (alternating current) disturbance with a set amplitude value to the fuel cell, and collecting excitation current and response voltage; performing fast Fourier transform to obtain harmonic response of each order under target frequency, and calculating first-order frequency response function and second-order frequency response function; forming a nonlinear impedance fault dataset, and performing fault feature extraction and dimensionality reduction on the dataset by principal component analysis; constructing a fault diagnosis model and training it according to the fault dataset after dimensionality reduction; and applying alternating current disturbance with a set amplitude to the fuel cell, collecting voltage and current data, calculating frequency response function, inputting the frequency response function into the trained fault diagnosis model after dimensionality reduction, and diagnosing the current health status of the fuel cell in real time.

[0007] CN 113540534 A describes a starvation fault diagnosis method for a proton exchange membrane fuel cell stack. The method comprises the following steps: calculating an index parameter for starvation fault diagnosis by the real and imaginary part values corresponding to the specific frequency of EIS (electrochemical impedance spectrum) and the fuel cell internal resistance model; performing principal component analysis and K-means clustering for classification by using starvation data and normal stack data obtained via simulation as initial analysis data to obtain two centroid points mu1 and mu2 of normal cluster set and starvation cluster set; comparing the data points under different operating conditions obtained by using principal component analysis and K-means clustering with the centroid point mu1 of the normal data cluster set and the centroid point mu2 of the starvation data cluster set, so that it can be judged whether the stack has a starvation fault and the degree of starvation fault at this time.

[0008] JP 2020-205202 A relates to a fuel cell system in which reduction in accuracy in determining whether or not there is a fuel starvation state can be avoided while achieving reduction in manufacturing cost. Assuming that such a fuel cell system is composed of a first fuel cell and a second fuel cell each of which has a plurality of single cells of the same type stacked therein, the fuel cells respectively have first and second voltage detection devices, the fuel cell system includes a control device that controls the fuel cells based on detection results of the voltage detection devices, the first voltage detection device detects a voltage of cells per N pieces on average, and the second voltage detection device detects a voltage of the entire second fuel cell or a voltage of single cells per M pieces (more than N pieces) on average. When a predetermined condition in which states of the first and second fuel cells can be regarded as close to each other is satisfied, the control device determines whether or not any of the single cells of the second fuel cell is in a fuel starvation state based on the detection result of the first voltage detection device.

[0009] As known from the prior art, systems and methods for handling fuel starvation problems in hydrogen fuel cells can not fully meet certain requirements with respect to future operations, in particular on board of an aircraft. This is especially true in view of known systems and methods such as Cell Voltage Monitoring (CVM) or EIS which can not timely detect local fuel cell starvation. This in turn can lead to those fuel starvation events which are detected too late to initiate an effective countermeasure and thus can not prevent performance loss (aging) and eventually total cell stack loss. SUMMARY

[0010] It can therefore be seen as an object to provide an improved method of detecting and resolving fuel cell starvation problems. Furthermore, it can be seen as an object to enhance the reliability and safety of a fuel cell system. These objects are at least partially achieved by the subject matter of the various main aspects.

[0011] According to one aspect, a method for operating a fuel cell device, in particular a fuel cell system of a transportation vehicle such as an aircraft, is provided, the method comprising the steps of: acquiring at least one reaction temperature value representing a reaction temperature of a fuel such as hydrogen gas when being converted within the fuel cell device; acquiring at least one system temperature value representing a system temperature of the fuel cell device; monitoring a temperature difference between the at least one reaction temperature value and the at least one system temperature value; and initiating at least one starvation damage countermeasure to avoid local fuel starvation of the fuel cell device if the temperature difference indicates a fuel starvation likelihood.

[0012] According to an aspect, a control program for controlling a fuel cell device, in particular a fuel cell system of a vehicle such as an aircraft, is provided, wherein the control program comprises instructions which, when the control program is executed by a control device, cause the control device to perform a corresponding method.

[0013] According to an aspect, a computer-readable data carrier having stored thereon a control program is provided.

[0014] According to an aspect, a control device for controlling an energy conversion device of a vehicle such as an aircraft is provided, wherein the control device is configured to perform a corresponding method and / or comprises a corresponding computer-readable data carrier.

[0015] According to an aspect, a fuel cell device for a vehicle, in particular an aircraft, is provided, which is configured to perform a corresponding method and / or comprises a corresponding control device.

[0016] According to an aspect, a vehicle, in particular an aircraft, is provided, which comprises a corresponding fuel supply device.

[0017] The proposed solution provides alternative methods for detecting and addressing fuel cell starvation problems in various devices, vehicles, etc., including but not limited to aircraft. This includes energy systems for aircraft comprising fuel cells for aircraft propulsion and / or APU. Compared to the prior art, the proposed solution enables an increase in the lifetime, reliability and safety of fuel cell systems, in particular under operating conditions involving highly dynamic loads and changing environments. An advantage of the proposed solution is that previously undetectable fault conditions involving local fuel starvation can be detected. Thus, irreversible cell stack degradation and eventual cell stack loss can be avoided.

[0018] Obtaining at least one reaction temperature value and / or system temperature value can involve measuring a corresponding representative temperature value. For measuring a corresponding representative temperature value, any type of temperature measuring device can be used, such as a thermocouple, a positive temperature coefficient (PTC) thermistor, an infrared measuring device comprising an infrared camera, etc. As a starvation damage countermeasure, for example, the cooling capacity of the fuel cell device can be increased, e.g. by increasing the coolant flow. Alternatively or additionally, to stop local fuel starvation, the hydrogen volume flow provided to the fuel cell device, the hydrogen recirculation of the fuel cell system and / or the hydrogen concentration within the fuel cell system can be increased, e.g. by opening a purge valve at the outlet of the fuel cell system (e.g. anode).

[0019] The solution provides, inter alia, control measures and corresponding control devices, which are suitable for all types of installations, including failure-intolerant and / or safety-critical systems. Corresponding installations including fuel cell installations can be provided, inter alia, in the form of vehicles, such as land vehicles, watercraft, aircraft and / or spacecraft or technical equipment, and / or in the form of any utility provider infrastructure, such as power plants, energy network facilities, etc. The control devices for solving potential problems can include corresponding computing devices. The control devices can be implemented as and / or include corresponding computing devices. The computer-readable data carriers can include and / or consist of computer-readable media and / or data carrier signals.

[0020] Further refinements can be derived from the respective additional aspects and the following description. Features described with reference to the devices and installations can be implemented as method steps, or features described with reference to the method steps can be implemented as devices and installations. The description provided in the context of the control devices, fuel cell installations and / or vehicles thus also applies in an analogous manner to the corresponding methods. In particular, the functions of the control devices, fuel cell installations and / or vehicles and their or its components can be implemented as method steps of the respective methods, respectively, and the method steps can be implemented as functions of the control devices, fuel cell installations and / or vehicles and the corresponding installation features.

[0021] According to an embodiment of the method, at least one reaction temperature value and / or at least one system temperature value is acquired at and / or within at least one fuel cell stack of the fuel cell installation, respectively. The at least one reaction temperature value can be acquired individually for each of the fuel cell stacks of the fuel cell installation and / or for individual fuel cell elements. Thus, the respective temperature differences can be monitored, preferably in a direct and differentiated manner. This enables a further improved detection and localization of potential fuel starvation events.

[0022] According to an embodiment of the method, the at least one reaction temperature value is acquired at an anode side of the fuel cell installation. Experience shows that fuel starvation problems can occur in particular at the anode side of the fuel cell. Thus, measuring the at least one reaction temperature value at the anode side further contributes to a quick detection of potential fuel starvation events.

[0023] According to an embodiment of the method, the at least one reaction temperature value represents an exhaust temperature of an exhaust of the fuel cell installation. The exhaust can include any reaction products of the fuel conversion in the fuel cell installation. Measuring the at least one reaction temperature value such that it represents the exhaust temperature and / or the respective temperature of the conversion products further contributes to a quick and reliable detection of potential fuel starvation events.

[0024] According to an embodiment of the method, at least one reaction temperature value is acquired in the region of at least one anode exhaust outlet of the fuel cell device. The at least one reaction temperature value can be acquired individually at each cell stack exhaust outlet of the fuel cell device. Acquiring the at least one reaction temperature value in the region of the anode exhaust outlet contributes to providing a combined parameter for assessing any temperature change and any fuel cell connected to the respective anode exhaust outlet and / or cell stack exhaust outlet. Thus, potential fuel starvation events can be kept undetected.

[0025] The at least one system temperature value can be acquired in a thermal management system of the fuel cell device. The thermal management system can be most suitable for acquiring the at least one system temperature value, as the thermal management system contributes to regulating the overall temperature level of the fuel cell device. This contributes to providing the at least one system temperature value as a reliable parameter for determining the temperature difference and safely assessing the occurrence of a potential fuel starvation event.

[0026] According to an embodiment of the method, the at least one system temperature value represents a coolant temperature of a cooling medium of the fuel cell device. The cooling medium is used for regulating the overall temperature level of the fuel cell device. Thus, acquiring the at least one system temperature value such that it represents the coolant temperature further contributes to providing the at least one system temperature value as a reliable parameter for determining the temperature difference and safely assessing any occurrence of a potential fuel starvation event.

[0027] According to an embodiment of the method, the at least one system temperature value is measured at a coolant outlet and / or a coolant inlet of at least one fuel cell unit of the fuel cell device. In particular in the region of the coolant outlet and / or the coolant inlet, the respective coolant temperature can be indicative of any representative system temperature value of the fuel conversion in the fuel cell device. Thus, measuring the at least one system temperature value at the coolant outlet and / or the coolant inlet further contributes to quickly and reliably detecting a potential fuel starvation event.

[0028] According to an embodiment of the method, the temperature difference is compared to a temperature threshold value indicative of a likelihood of a fuel starvation. The monitoring process should cover any temperature difference that can occur within a certain monitoring time range, which is preferably in the range of a fraction of a second or even lower. The temperature threshold value can represent an allowed temperature difference and can be determined in a sliding or moving scale manner for determining whether the temperature difference is indicative of a potential fuel starvation event. This further contributes to quickly and reliably detecting any fuel starvation event under dynamic operating conditions.

[0029] According to an embodiment of the method, an oxygen concentration value, a carbon dioxide concentration value and / or a carbon monoxide concentration value within the fuel cell device is monitored and compared to a respective concentration threshold value indicative of a fuel starvation likelihood. In particular, the oxygen concentration value, the carbon dioxide concentration value and / or the carbon monoxide concentration value can be measured. Monitoring the oxygen concentration value, the carbon dioxide concentration value and / or the carbon monoxide concentration value can be used as an alternative and / or additional solution to detect potential fuel starvation events. In other words, monitoring the oxygen concentration value and / or the carbon dioxide concentration value and / or the carbon monoxide concentration value can be used in combination with the previously described temperature-based evaluation and can be provided as an alternative way to detect potential fuel starvation events. Thereby, the detection of any potential fuel starvation event, in particular under dynamic conditions, can be further improved.

[0030] According to an embodiment of the method, the evaluation of the indication of a fuel starvation likelihood involves a prediction of at least one reaction temperature value, at least one system temperature value and / or a temperature difference during a static and / or dynamic operation of the fuel cell device. The overall and / or individual temperature values during the static and / or dynamic operation can be predicted. The prediction is preferably performed in real-time, e.g. by an artificial intelligence (AI) / machine learning (ML) algorithm, and can enable a timely prediction and / or inference of possible countermeasures to avoid any fuel starvation event and subsequent carbon corrosion processes. Thereby, a continuous control of the fuel cell device can be achieved. Such a continuous control enables to avoid any critical operating states of the fuel cell device and thus further contributes to prevent fuel starvation events. BRIEF DESCRIPTION OF DRAWINGS

[0031] The subject matter will be described in the following with reference to the accompanying drawings, in which identical or similar parts are designated by identical reference signs, and in which:

[0032] Figure 1 is a schematic view of a vehicle in the form of an aircraft comprising a fuel cell device.

[0033] Figure 2 is a schematic view of a fuel cell device.

[0034] Figure 3 is a schematic view of a fuel cell unit of a fuel cell device in a normal operating state.

[0035] Figure 4 is a schematic view of a fuel cell unit of a fuel cell device in a fuel starvation state.

[0036] Figure 5 is a schematic view of a temperature difference comprising a reaction temperature value and a system temperature value. DETAILED DESCRIPTION

[0037] The following detailed description is merely exemplary in nature and is not intended to limit the application and use of the application. Furthermore, there is no intention to be bound by any theory of operation presented in the preceding background or the following detailed description. Representations and illustrations in the drawings are schematic and not drawn to scale. Like reference numerals designate like elements. A better understanding of the described subject matter will be obtained through a review of the drawings and the subsequent detailed description.

[0038] Figure 1 A schematic representation of an apparatus in the form of a vehicle 1, such as an aircraft, is shown, the apparatus comprising a fuel cell apparatus 2 configured to provide electric power E to the vehicle 1, for example to a propulsion unit 3 thereof. A control device 4 for controlling the operation of the vehicle 1, the fuel cell apparatus 2 and / or the propulsion unit 3 can be provided as part of the vehicle 1 and / or can be integrated into the fuel cell apparatus 2 itself. The control device 4 can be connected to the vehicle 1, the fuel cell apparatus 2 and / or the propulsion unit 3 via respective transmission lines 5, which can be configured to transmit data and / or electric power E in any type of wired and / or wireless manner.

[0039] The control device 4 can comprise a processing unit 6, an interface module 7, a storage module 8 and / or a control element 9, which can be connected to each other via respective transmission lines 5, which can be configured to contact any kind of information, data, electric power and / or energy. The vehicle 1 and / or the fuel cell apparatus 2 can be provided with a computing apparatus 10, which can comprise the control device 4, or the control device 4 can comprise the computing apparatus 10. A computer program 11 can be stored on a computer-readable data carrier 12, which can take the form of a computer-readable medium 13 and / or a data carrier signal 14. The control device 4 can comprise the computing apparatus 10, the computer program 11, the computer-readable data carrier 12 and / or any type of control element and transmission lines 5 for exchanging data between the respective aforementioned components. The control element 9 can be any type of data source, such as a measurement element, a sensor, an output device and / or an actuator of the vehicle 1, the fuel cell apparatus 2 and / or the propulsion unit, which can for example be connected to the control element 9 by means of the interface module 7 to form part of a control system for controlling a specific function thereof.

[0040] Figure 2 is a schematic representation of a fuel cell apparatus 2, which comprises at least one fuel cell unit 20, a fuel supply apparatus 21, an air supply apparatus 22 and a thermal management system 23. The fuel cell unit 20 can comprise a plurality of fuel cell stacks 24, each fuel cell stack 24 comprising at least one fuel cell element 25 (see Figure 3 and Figure 4). Each fuel cell stack 24 has an anode side A and a cathode side Z separated from each other by a membrane M.

[0041] The fuel cell unit 20 can be provided with a housing 30 which can enclose at least one fuel cell stack 24. The housing 30 is provided with an anode inlet 31, an anode outlet 32, a cathode inlet 33 and a cathode outlet 34. Through the anode inlet 31, fuel F, such as hydrogen gas, is provided to the fuel cell unit 20, in particular its anode side A. Through the anode outlet 32, anode exhaust J is discharged from the fuel cell unit 20, in particular its anode side A. Conversion gas G, such as air, for converting the fuel F is provided to the fuel cell unit 20, in particular its cathode side Z, through the cathode inlet 33. Through the cathode outlet 34, cathode exhaust K is discharged from the fuel cell unit 20, in particular its cathode side Z. Furthermore, the housing has a coolant inlet 35 and a coolant outlet 36 for introducing and discharging, respectively, a cooling medium B for cooling the fuel cell unit 20.

[0042] The fuel supply 21 comprises a fuel tank 40 and a fuel inlet valve 41. Optionally, the fuel supply 21 can comprise a recirculation pump 42. The fuel tank 40 contains fuel F which is controllably provided to the anode inlet 31 of the fuel cell unit 30 through the fuel inlet valve 41. The recirculation pump 42 can recirculate anode exhaust J from the anode outlet 32 to the anode inlet 31. The recirculation pump 42 and / or an outlet valve 43 can controllably regulate the amount of recirculated anode exhaust J.

[0043] The air supply 22 has an air inlet 50, a compressor 51, an expansion device in the form of a turbine 52, a liquid separator 53 and an exhaust outlet 54. External air or any other conversion gas G can be provided to the fuel cell device 2 through the air inlet 50. The compressor 51 compresses the conversion gas G for provision to the fuel cell unit 20 through the cathode inlet 33. The amount and / or pressure of conversion gas G provided to the fuel cell unit 20 can be controllably regulated by the compressor 51 and / or an inlet valve 55.

[0044] The compressor 51 can be at least partially driven by energy generated by means of the turbine 52 which can expand exhaust L. This energy can be transferred from the turbine 52 to the compressor 51. Before entering the turbine 52, the exhaust L can be separated into vapour V and water W by means of the liquid separator 53. The vapour V can be directed through the turbine 52, while the water W bypasses the turbine 52. The exhaust L from the turbine 52 can be recombined with the exhaust L from the liquid separator 53 which bypasses the turbine 52 for then being discharged from the vehicle 1 and / or the fuel cell device 2 through the exhaust outlet 54.

[0045] The thermal management system 23 comprises a coolant pump 60, a coolant valve 61 and a heat exchanger 62. The flow of the cooling medium B through the thermal management system 23, in particular the heat exchanger 62, and the fuel cell unit 10 can be regulated in a controllable manner by the coolant pump 60 and / or the coolant valve 61. Furthermore, the coolant valve 61 can enable the coolant B to be fed into and discharged from the thermal management system 23, respectively. Through the heat exchanger 62, the heat contained in the coolant B can be dissipated to the outside of the thermal management system 23 as desired and / or required.

[0046] The conduits 90 of the fuel cell device 2 can be provided in any number, form, shape and / or material as desired or required for connecting components of the fuel cell device 2 to each other in order to guide and / or process the fuel F, the reforming gas G, the cooling medium B, the anode exhaust J, the cathode exhaust K, the exhaust L, the steam V and / or the water W as desired or required to achieve the respective functions. The conduits 90 and / or components can be provided with sensors 91 and / or actuators 92 as desired and / or required. The sensors 91 and / or actuators 92 can be configured to acquire, measure, set, control and / or adjust any pressure P, temperature T and / or chemical composition U of the components of the fuel cell device 2, the fuel F, the reforming gas G, the cooling medium B, the anode exhaust J, the cathode exhaust K, the exhaust L, the steam V and / or the water W, respectively, as desired or required to achieve the respective functions. The conduits 90, sensors 91 and / or actuators 92 can serve as, be configured to comprise and / or constitute control elements 9 for controlling any of their functions by means of the control device 4 during operation of the vehicle 1 and / or the fuel cell device 2 and / or the propulsion unit 3.

[0047] Figure 3 is a schematic representation of a fuel cell unit 20 of the fuel cell device 2 in a regular or normal operating state R. In the present example, the reaction of the fuel F in the form of hydrogen H with the reforming gas G in the form of oxygen O within one of the fuel cell elements 25 of the fuel cell unit 20 is shown in exemplary manner. Under normal operating conditions R, the reaction mechanism between hydrogen H and oxygen O occurs as hydrogen H oxidation (hydrogen dissociation) reaction at the anode side A and as oxygen O reduction (water generation) reaction on the cathode side Z. The water W generation is an exothermic reaction, responsible for the heating of the fuel cell element 25, while the hydrogen H reaction is a slightly endothermic reaction, whose thermal contribution is usually negligible. The thermal management system 23 can be designed with respect to the thermal contribution of the reactions on the cathode side Z. For this reason and due to the fact that the cooling medium B is the fluid with the highest thermal mass, the gas temperature T 32 and / or the gas temperature T 34 at the cathode outlet 34 should be equal to or at least close to the temperature T B of the coolant B.

[0048] Figure 4 is a schematic diagram of a fuel cell unit 20 of a fuel cell device in which the fuel cell element 25 is in a fuel starvation state S. In the case of a partial fuel starvation reaction, the reaction mechanism changes along the path through the anode and cathode channels compared to the normal state R. The water W formation reaction partially occurs on the anode side A, while carbon C corrosion occurs on the cathode side. Both reactions are strongly exothermic (dh H2O : -286 kJ / mol and dh CO2 : -394 kJ / mol). This will lead to a temperature increase of the gas temperatures T 32 and T 34 to values above the coolant temperature T B of the coolant B and thus to the characteristic temperature difference D. In particular, the gas at the anode side has a relatively small thermal mass and is thus very sensitive to the heat generated in terms of temperature changes.

[0049] Figure 5 is a schematic diagram of a temperature difference D between a reaction temperature value T X (e.g. a gas temperature T 32 and / or T 34 ) and a system temperature value T Y (e.g. a coolant temperature T B ). For example, the temperature difference D between the coolant outlet 36 and the anode outlet 32 and / or the cathode outlet 34 can be monitored by means of a sensor 91 measuring the respective temperature values T. When the temperature difference D exceeds a predefined threshold value Q, this can indicate a potential fuel starvation event. To prevent entry into the starvation state S, an intervention I and / or countermeasures can be initiated by the control device 4, for example, by increasing the fuel F flow by correspondingly adjusting the fuel inlet valve 41 and / or the recirculation pump 42, which can be combined with a purge through the outlet valve 43, and alternatively or additionally, by increasing the amount and / or lowering the temperature T B of the cooling medium B by corresponding adjustments of the operation of, for example, the coolant pump 60, the coolant valve 61 and / or the heat exchanger 62 to increase the cooling capacity.

[0050] To detect a reaction temperature value T X (e.g. a gas temperature T 32 and T 34 ) and a system temperature value T Y (e.g. a coolant temperature T Bbetween the gas temperature and the coolant temperature) and in order to initiate countermeasures I, corresponding logic can be implemented in the control device 4, the computing device 10 and / or the computer program 11. Such logic can rely on historical measurement data, which can be stored and accessed by the processing unit 6 in the storage module 8. Thus, any logic including artificial intelligence (AI) or machine learning (ML) algorithms can use such historical data in order to heuristically and / or statistically develop a rule set for assessing whether a normal operating state R or a starvation state S is imminent and what countermeasures I can be taken to prevent any damage to the affected fuel cell elements 25. Alternatively or additionally, the prediction of overall and / or individual temperature values by the AI / ML algorithms, preferably in real-time during static and / or dynamic operation, can enable to timely predict and / or deduce possible countermeasures I to avoid any fuel starvation event and subsequent carbon corrosion processes.

[0051] List of reference signs

[0052] 1 vehicle / aircraft 36 coolant outlet

[0053] 2 fuel cell device 40 fuel tank

[0054] 3 propulsion unit 41 fuel inlet valve

[0055] 4 control device 42 recirculation pump

[0056] 5 transfer line 43 outlet valve

[0057] 6 processing unit 50 air inlet

[0058] 7 interface module 51 compressor

[0059] 8 storage module 52 turbine

[0060] 9 control element 53 liquid separator

[0061] 10 computing device 54 exhaust outlet

[0062] 11 computer program 55 inlet valve

[0063] 12 computer-readable data carrier 60 coolant pump

[0064] 13 computer-readable medium 61 coolant valve

[0065] 14 data carrier signal 62 heat exchanger

[0066] 20 fuel cell element e electronic

[0067] 21 fuel supply device A anode side

[0068] 22 air supply device B cooling medium

[0069] 23 thermal management system C carbon

[0070] 24 fuel cell stack D temperature difference

[0071] 25 fuel cell element E electric power

[0072] 30 housing F fuel

[0073] 31 anode inlet G reforming gas / air / oxygen

[0074] 32 anode outlet H hydrogen

[0075] 33 cathode inlet I intervention / countermeasure

[0076] 34 cathode outlet J anode exhaust

[0077] 35 coolant inlet K cathode exhaust

[0078] L exhaust

[0079] M membrane

[0080] O oxygen

[0081] P pressure

[0082] Q threshold value

[0083] R normal operation state

[0084] S starvation state

[0085] T temperature value

[0086] U component / concentration

[0087] V vapor

[0088] W water

[0089] X reaction

[0090] Y system

[0091] Z cathode side

Claims

1. A method for operating a fuel cell device (2) of a fuel cell system, in particular of a vehicle (1) such as an aircraft, the method comprising the following steps: at least one reaction temperature value (T X ) is acquired, which at least one reaction temperature value (T X ) is representative of a reaction temperature of a fuel (F), such as hydrogen, when the fuel is undergoing conversion within the fuel cell device (2); obtaining at least one system temperature value (T Y ) representing a system temperature of the fuel cell device (2); monitoring a temperature difference (D) between the at least one reaction temperature value (T X ) and the at least one system temperature value (T Y ); and - if the temperature difference (D) indicates a fuel starvation likelihood, initiating at least one starvation damage countermeasure to avoid a local fuel starvation state (S) of the fuel cell device (2).

2. The method for operating a fuel cell device (2) according to claim 1, wherein, The at least one reaction temperature value (T X ) and / or the at least one system temperature value (T Y ) are / is respectively acquired at and / or within at least one fuel cell stack (20) and / or fuel cell element (25) of the fuel cell device (2).

3. The method for operating a fuel cell device (2) according to claim 1 or 2, wherein, The at least one reaction temperature value (T X ) is acquired at the anode side (A) of the fuel cell device (2).

4. The method for operating a fuel cell device (2) according to at least one of claims 1 to 3, wherein The at least one reaction temperature value (T X ) represents an exhaust temperature (T) of the exhaust (L) of the fuel cell device.

5. The method for operating a fuel cell device (2) according to at least one of claims 1 to 4, wherein The at least one reaction temperature value (T X ) is acquired in the region of at least one anode exhaust outlet (32) of the fuel cell device (2).

6. The method for operating a fuel cell device (2) according to at least one of claims 1 to 5, wherein The at least one system temperature value (T Y ) represents a coolant temperature (T B ) of a cooling medium (B) of the fuel cell device (2).

7. The method for operating a fuel cell device (2) according to at least one of claims 1 to 6, wherein measuring at least one system temperature value (T Y ) at a coolant outlet (36) and / or a coolant inlet (35) of at least one fuel cell unit (20) of the fuel cell device (2).

8. The method for operating a fuel cell device (2) according to at least one of claims 1 to 7, wherein said temperature difference (D) is compared to a temperature threshold value (Q T ) indicative of a likelihood of fuel starvation.

9. The method for operating a fuel cell device (2) according to at least one of claims 1 to 8, wherein monitoring oxygen concentration values (U O ), carbon dioxide concentration values (U CO2 ) and / or carbon monoxide concentration values (U CO ) within the fuel cell device (2) and comparing them with respective concentration thresholds (Q U ) indicative of a fuel starvation likelihood.

10. The method for operating a fuel cell device (2) according to at least one of claims 1 to 9, wherein The evaluation of the indication of the possibility of fuel starvation involves a prediction of the at least one reaction temperature value (T X ), the at least one system temperature value (T Y ) and / or the temperature difference (D) during static and / or dynamic operation of the fuel cell device (2).

11. A control program (11) for controlling a fuel cell device (2), in particular a fuel cell device (2) of a fuel cell system of a vehicle (1), such as an aircraft, wherein - the control program (11) comprises instructions which, when the control program is executed by a control device (4), cause the control device (4) to perform the method according to at least one of claims 1 to 10.

12. A computer-readable data carrier (12) having stored thereon a control program according to claim 11.

13. A control device (4) for controlling an energy conversion installation of a vehicle (1), such as an aircraft, wherein - the control device (4) is configured to perform the method according to at least one of claims 1 to 10 and / or comprises the computer-readable data carrier (12) according to claim 12.

14. A fuel cell device (2) for a vehicle (1), in particular an aircraft, configured to perform the method according to at least one of claims 1 to 10 and / or comprising the control device (4) according to claim 13.

15. A vehicle (1), in particular an aircraft, comprising a fuel cell device (2) according to claim 14.

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