Method for determining fuel cell stack information after switch-off and vehicle

Abstract

A method for determining information about a fuel cell stack (100) of a vehicle (200) after switch-off includes, as one step, recognizing a switch-off command and, as another step, closing a cathode gas inlet valve and closing a cathode gas outlet valve to fluidically isolate the cathode region (K). It also includes, as one step, connecting an electrical load (230) to the fuel cell stack (100) until a predetermined target voltage is recognized and, as another step, closing an anode gas inlet valve and closing an anode gas outlet valve to fluidically isolate the anode region (A). It also includes, as a step, applying an electrical measurement signal to the fuel cell stack (100) and, as another step, detecting a signal response.

Description

[Technical Field]

[0001] A fuel cell is an electrochemical energy converter in which, for example, hydrogen and oxygen are converted into water, electrical energy and heat. [Background technology]

[0002] Impedance measurements can be used to obtain information about the electrical or electrochemical state / properties of a fuel cell. Summary of the Invention

[0003] The invention relates to a method for determining information about at least one stack part of a fuel cell stack of a fuel cell system of a vehicle after switching off the vehicle according to the features of claim 1, a vehicle according to the features of claim 10, a computer program product according to the features of claim 11, a computer readable medium according to the features of claim 12 and a data carrier signal according to the features of claim 13.

[0004] Other features and details of the invention will become apparent from the dependent claims, the following description and the drawings, in which case features and details explained in the context of the method according to the invention naturally also apply in the context of the vehicle according to the invention, the computer program product according to the invention, the computer-readable medium according to the invention and the data carrier signal according to the invention, and vice versa, whereby reference is or can always be made to each other in relation to the disclosure of the individual aspects of the invention.

[0005] According to a first aspect, the present invention provides a method for determining information about at least one stack part of a fuel cell stack of a fuel cell system of a vehicle after switching off the vehicle. The method includes, as a step, recognizing a switch-off command for switching off the vehicle. Furthermore, the method includes, as a step, closing a cathode gas inlet valve of the fuel cell system and closing a cathode gas outlet valve of the fuel cell system to fluidically isolate a cathode region of the fuel cell stack in which an air mixture is present in the cathode region, if the switch-off command is recognized. Furthermore, the method includes, as a step, connecting an electrical load device to at least one stack part of the fuel cell stack in order to reduce the proportion of oxygen in the air mixture in the blocked cathode region of the fuel cell stack, the electrical load device being connected at least until a predetermined target voltage is recognized. Furthermore, the method includes, as a step, closing an anode gas inlet valve of the fuel cell system and closing an anode gas outlet valve of the fuel cell system to fluidically isolate an anode region of the fuel cell stack in which a fuel mixture is present in the anode region, if the predetermined target voltage is recognized. The method further comprises a step of applying an electrical measurement signal to at least one stack section of the fuel cell stack, particularly when the anode gas inlet valve and the anode gas outlet valve are closed. The method further comprises a step of detecting a signal response to the applied electrical measurement signal. The method further comprises a step of determining information relating to at least one stack section of the fuel cell stack of the fuel cell system based on the applied measurement signal and the detected signal response.

[0006] The method steps described above and below can be carried out individually, together, once, several times, in parallel in time and / or sequentially in any order, insofar as this is technically meaningful.

[0007] The vehicle is in particular a motor vehicle, preferably a car or freight vehicle.

[0008] A fuel cell of a fuel cell stack can be understood as a stack portion of a fuel cell stack, or a plurality of fuel cells of a fuel cell stack, in particular a plurality of fuel cells electrically connected in series of a fuel cell stack, can be understood as a stack portion of a fuel cell stack.

[0009] The fuel cell stack itself may comprise a plurality of fuel cells, in particular the fuel cell stack may be a polymer electrolyte membrane fuel cell stack, preferably operable with air and fuel, in particular hydrogen.

[0010] Switching off the vehicle can also be understood as stopping the vehicle. In particular, in the switched-off state, the vehicle cannot be driven by a drive unit, e.g., a motor such as an electric motor. For example, the driver of the vehicle can switch off the vehicle using a switch-off button and / or the vehicle key. Alternatively or additionally, it is also conceivable for the vehicle to switch off automatically, provided at least one condition is met. In this case, for example, the start / stop function of the vehicle comes to mind.

[0011] The recognition of the switch-off command for switching off the vehicle can be recognized, for example, by a control device of the vehicle, in particular by a control unit.

[0012] The cathode inlet valve and / or cathode outlet valve and / or anode gas inlet valve and / or anode gas outlet valve are particularly arranged close to and / or directly on the fuel cell stack of the fuel cell system, for example, at a distance of 1 to 100 cm, particularly 5 to 50 cm, from the fuel cell stack of the fuel cell system.

[0013] In particular, the fluid chamber formed in a fluid engineering manner between the cathode inlet valve, the fuel cell stack and the cathode outlet valve can be considered as the cathode region, and in particular, the fluid chamber formed in a fluid engineering manner between the anode inlet valve, the fuel cell stack and the anode outlet valve can be considered as the anode region.

[0014] The electrical load device may be, for example, an electrical consumer device of a vehicle. In particular, the electrical load device is a variable load device. In other words, the electrical load provided by the electrical load device can be varied. In particular, the electrical load of the variable load device can be adjusted depending on the detected fuel cell stack voltage. Preferably, the electrical load of the variable load device is reduced at least once when the detected fuel cell stack voltage decreases. This can be particularly advantageous in reducing oxygen in the cathode region of the fuel cell stack.

[0015] Furthermore, in order to recognize when a predetermined target voltage of the fuel cell stack and / or at least one stack section of the fuel cell stack is reached, the voltage of the fuel cell stack or at least one stack section of the fuel cell stack is detected, for example by means of a voltmeter.

[0016] The target voltage of a single fuel cell of a fuel cell stack may be, for example, about 50 mV, in particular about 30 mV. If a voltage is detected to determine the target voltage of the (complete) fuel cell stack or of several fuel cells, the target voltage is in particular a corresponding multiple thereof. At such a target voltage, it can be considered that oxygen has been consumed or substantially consumed, in particular on the cathode side or in the cathode region of the fuel cell stack.

[0017] The electrical measurement signal is in particular a voltage measurement signal, and in particular a current signal response is detected as a signal response to an applied voltage measurement signal.

[0018] It is also conceivable that the electrical measurement signal is in particular a current measurement signal, and in particular a voltage signal response is detected as a signal response to the applied current measurement signal.

[0019] The application of the electrical measurement signal is preferably carried out by an application device, and the signal response is preferably detected by a detection device, and information relating to at least one stack part, in particular of a fuel cell stack of a fuel cell system, is further determined by the detection device.

[0020] The information relating to at least one stack portion of the fuel cell stack or the fuel cell stack may be, for example, information relating to the wettability state of the fuel cell stack or one or more components of the fuel cell stack, and / or information relating to the aging state of the fuel cell stack or one or more components of the fuel cell stack, and / or information relating to the electrical resistance state of the fuel cell stack or one or more components of the fuel cell stack.

[0021] By switching off the vehicle, then contacting the electrical load until a predetermined target voltage is reached, and then closing the anode inlet valve and the anode outlet valve, followed by closing the cathode inlet valve and the cathode outlet valve, the fuel cell or fuel cell stack of the fuel cell stack can be brought into a predetermined state. The predetermined state is in particular a hydrogen / nitrogen state (H2 / N2 state). Thus, since oxygen has been consumed or is substantially consumed (and therefore plays no or only a small role), information can be obtained about the ohmic resistance and the state of the ionomer, in particular, at the cathode of the fuel cell stack.

[0022] In the method according to the present invention, it may be advantageous if a measurement signal with a varying frequency is applied to determine at least several impedance values, in particular a measurement signal with a frequency varying between 100 kHz and 1 Hz, preferably between 50 kHz and 100 Hz. This allows for particularly simple acquisition of information about at least one stack section of a fuel cell stack of a fuel cell system. It is conceivable that the measurement signal is applied only at a number of frequencies, in particular, interpolation and / or extrapolation is performed, for example, by a vehicle control unit. This allows for particularly rapid determination of information about at least one stack section of a fuel cell stack of a fuel cell system. In the method according to the present invention, it is advantageous if ohmic losses and / or proton transport resistance of at least one stack section of a fuel cell stack of a fuel cell system are determined from the determined impedance values. The ohmic losses can be obtained, for example, from the zero crossings of an impedance curve (Nyquist diagram) generated from the determined impedance values. The proton transport resistance can be obtained, for example, from the slope. This allows for particularly simple acquisition of information about at least one stack section of a fuel cell stack of a fuel cell system. In particular, from the ohmic losses, a membrane state, e.g., the wetting of a membrane or membranes, and / or an electrical resistance state, e.g., the contact resistance, can be determined as information at least relating to at least one stack part of a fuel cell stack of a fuel cell system. Alternatively or additionally, from the proton transport resistance, a wetting state of an electrode or electrodes and / or a chemical degradation state of an ionomer or ionomers can be determined as information at least relating to at least one stack part of a fuel cell stack of a fuel cell system.

[0023] In the method according to the present invention, it may be advantageous if the temperature of at least one of the fuel cell stacks is detected and stored within a certain time range before the vehicle is switched off, and / or the power drawn from the fuel cell stack is detected and stored within a certain time range before the vehicle is switched off, and the detected temperature of the fuel cell stack and / or the detected power drawn from the fuel cell stack is taken into account to determine information relating to at least one stack section of the fuel cell stack of the fuel cell system. This allows the determination of information relating to at least one stack section of the fuel cell stack of the fuel cell system to be particularly accurate and dependent on the state of the fuel cell stack immediately before the vehicle is switched off. For example, in the vehicle's storage device, the temperature of at least one of the fuel cell stacks, e.g., the coolant temperature, may be detected and stored within a time range of 2 to 20 minutes, particularly 5 to 15 minutes, before the vehicle is switched off, and / or the power drawn from the fuel cell stack may be detected and stored. In particular, the vehicle is in a driving mode in which the vehicle is or can be moved by the drive unit of the vehicle, for example by pressing the accelerator pedal, before the switch-off. For example, reference data can be stored in the vehicle and / or in the cloud in order to take the detected temperature and / or the called power into account for determining information relating to at least one stack part of the fuel cell stack, so that the influence of the temperature and / or the called power before switching off the vehicle can be taken into account when determining the information.

[0024] It may be advantageous if the method according to the present invention is executed several times, successively after the vehicle is switched off while the vehicle is continuously switched off, in particular at specific time intervals. This allows the development of information about at least one stack part of the fuel cell stack of the fuel cell system over time to be observed and, if necessary, further information to be obtained from this. It is conceivable that the method according to the present invention is executed at specific time intervals, for example, every five minutes, after the vehicle is switched off. If, during the execution of the method according to the present invention, a switch-on command to switch on the vehicle is recognized, for example, by a recognition device, the method according to the present invention is preferably terminated depending on the estimated remaining time. This prevents the vehicle driver from having to wait for the method to end if a long remaining time is expected, for example, if a remaining time longer than five seconds is expected.

[0025] In the method according to the invention, it may be advantageous if the reference data is stored in the vehicle and / or in a cloud, and the reference data is used to determine (based on the applied measurement signals and the detected signal responses) information relating to at least one stack part of the fuel cell stack of the fuel cell system. By storing the reference data in the vehicle itself, the information relating to at least one stack part of the fuel cell stack of the fuel cell system can be particularly easily obtained. For example, the reference data can be saved or stored in a storage device, in particular a non-volatile memory, of the vehicle. By saving the reference data in a cloud, the reference data can be particularly easily kept up to date, so that the information relating to at least one stack part of the fuel cell stack of the fuel cell system can be particularly accurate. The cloud can also be understood as a data collection. The reference data can, for example, comprise impedance values ​​and / or impedance curves.

[0026] In the method according to the invention, it may be advantageous if information about the complete fuel cell stack of the fuel cell system is determined based on the applied measurement signals and the detected signal responses, and / or information is determined for each of a plurality of stack parts of the fuel cell stack of the fuel cell system based on the respective applied measurement signals and the respective detected signal responses. By determining information about the complete fuel cell stack of the fuel cell system, an overall assessment of the state of the fuel cell stack can be made. Advantageously, since information is not obtained for each of a plurality of stack parts of the fuel cell stack of the fuel cell system, the determination of information about the complete fuel cell stack of the fuel cell system can be carried out particularly quickly.

[0027] By determining information about each of the multiple stack sections of a fuel cell stack of a fuel cell system based on the respective applied measurement signals and the respective detected signal responses, it is possible to make an assessment, in particular, of the state of each of the multiple stack sections of the fuel cell stack, for example, of each of the multiple stack sections.

[0028] It may be advantageous if, in the method according to the invention, a message is displayed to a vehicle occupant depending on the determined information. For example, the vehicle occupant may be informed that the fuel cell system or fuel cell stack is in good condition and that the vehicle can be safely driven. If the fuel cell stack is in a critical state, a message may also be displayed to the vehicle occupant instructing them to take some action, such as visiting a repair shop. A vehicle occupant may in particular be understood as the driver of the vehicle.

[0029] In the method according to the present invention, it may be advantageous if the information determined after the vehicle is switched off is taken into account for starting the fuel cell system when the vehicle is switched on, and in particular, a start-up procedure for the fuel cell system is defined based on the determined information in order to take the determined information into account for starting the fuel cell system. This can particularly advantageously minimize deterioration of the fuel cell system or fuel cell stack. For example, if the method according to the present invention determines information that one or more electrodes of the fuel cell stack are too lightly wetted, countermeasures can be taken at the next switch-on. For example, a corresponding start-up procedure can be defined depending on reference data stored, for example, in the vehicle and / or in the cloud.

[0030] According to a second aspect, the present invention relates to a vehicle designed to perform a method for determining information about at least one stack part of a fuel cell stack of a fuel cell system of the vehicle after the vehicle is switched off. The vehicle comprises a recognition device for recognizing a switch-off command for switching off the vehicle. The vehicle further comprises a fuel cell system having a fuel cell stack, the cathode region of which can be fluidically isolated by a cathode gas inlet valve and a cathode gas outlet valve, and the anode region of which can be fluidically isolated by an anode gas inlet valve and an anode gas outlet valve. The vehicle further comprises an electrical load device contactable with at least one stack part of the fuel cell stack. The vehicle further comprises an application device for applying an electrical measurement signal to at least one stack part of the fuel cell stack. The vehicle further comprises a detection device for detecting a signal response to the applied electrical measurement signal. The vehicle further comprises a determination device for determining at least information about at least one stack part of the fuel cell stack of the fuel cell system based on the applied measurement signal and the detected signal response.

[0031] Preferably, means or equipment already necessary for the operation of the fuel cell system, such as a control unit, are used to carry out the method according to the invention.

[0032] Furthermore, the vehicle is provided with a voltage detection device, in particular a voltmeter for detecting the voltage of the fuel cell stack and / or at least one stack section of the fuel cell stack, in order to be able to recognize when a predetermined target voltage of the fuel cell stack and / or at least one stack section of the fuel cell stack has been reached. The recognition of reaching the predetermined target voltage can be achieved, for example, by means of a control device.

[0033] Thus, the vehicle according to the second aspect of the invention has the same advantages as already described for the method according to the first aspect of the invention.

[0034] According to a third aspect, the invention provides a computer program product comprising instructions causing a vehicle, in particular a vehicle according to the invention, to carry out the method steps according to the method according to the invention.

[0035] The computer program product may be implemented as computer-readable instruction code, but may also be realized at least partly by software and by one or more special electronic circuits, i.e., in the form of hardware, or in any hybrid form, i.e., by software and hardware components.

[0036] The computer program product according to the third aspect of the invention therefore has the same advantages as those already described for the method according to the first aspect of the invention or the vehicle according to the second aspect of the invention.

[0037] According to a fourth aspect, the present invention provides a computer-readable medium on which a computer program product according to the present invention is stored.

[0038] In particular, the computer program product may be stored on a computer-readable storage medium such as a data disk, a disk drive, a volatile or non-volatile memory, or an on-board storage device / processor.

[0039] The computer readable medium according to the fourth aspect of the invention therefore has the same advantages as those already described for the method according to the first aspect of the invention or the vehicle according to the second aspect of the invention or the computer program product according to the third aspect of the invention.

[0040] According to a fifth aspect, the present invention provides a data carrier signal carrying a computer program product according to the present invention.

[0041] In particular, the computer program product may be or can be provided over a network, such as the Internet, from which it can be downloaded or executed online by a user when required.

[0042] The data carrier signal according to the fifth aspect of the invention therefore has the same advantages as already described for the method according to the first aspect of the invention, or the vehicle according to the second aspect of the invention, or the computer program product according to the third aspect of the invention, or the computer readable medium according to the fourth aspect of the invention.

[0043] Other measures for improving the present invention will become apparent from the following description of some exemplary embodiments of the invention, which are diagrammatically illustrated in the drawings. All features and / or advantages, including structural details, spatial arrangements and method steps, which emerge from the claims, the following description or the drawings, may be material to the present invention, either alone or in various combinations. It should be noted, then, that the drawings are merely illustrative in nature and are not intended to limit the present invention in any way. [Brief explanation of the drawings]

[0044] [Figure 1] FIG. 1 shows a schematic diagram of a method. [Figure 2] FIG. 1 is a diagram illustrating a vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0045] In the following figures, the same reference numerals are used for the same technical features according to different exemplary embodiments.

[0046] 1 discloses a method for determining information about at least one stack part of a fuel cell stack 100 of a fuel cell system 210 of a vehicle 200 after the vehicle 200 is switched off (see, for example, FIG. 2 in this regard). The method comprises a step of recognizing 320 a switch-off command for switching off the vehicle 200. Furthermore, if a switch-off command is recognized, the method comprises a step of closing 341, in particular completely closing, a cathode gas inlet valve of the fuel cell system 210, and a step of closing 342, in particular completely closing, a cathode gas outlet valve of the fuel cell system 210, in order to fluidically isolate the cathode region K of the fuel cell stack 100 in which an air mixture is present in the cathode region K. Furthermore, the method comprises a step of connecting 360 an electrical load 230, for example an electrical consumer, to at least one stack part of the fuel cell stack 100 in order to reduce the proportion of oxygen in the air mixture in the isolated cathode region K of the fuel cell stack 100, the electrical load 230 being connected at least until a predetermined target voltage is recognized 370. The method further comprises the steps of closing 381, in particular completely, the anode gas inlet valve of the fuel cell system 210 and closing 382, ​​in particular completely, the anode gas outlet valve of the fuel cell system 210, in order to fluidically isolate the anode region A of the fuel cell stack 100, in which the fuel mixture is present in the anode region A, when the predetermined target voltage is recognized. The method further comprises the step of applying 400 electrical measurement signals, such as voltage measurement signals and / or current measurement signals, to at least one stack section of the fuel cell stack 100, in particular when the anode gas inlet valve and the anode gas outlet valve are closed. The method further comprises the step of detecting 420 a signal response to the applied electrical measurement signals. The method further comprises the step of determining 440 information relating to at least one stack section of the fuel cell stack 100 of the fuel cell system 210 based on the applied measurement signals and the detected signal response, for example by comparing it with reference data.In particular, the information determined after the vehicle 200 is switched off can be taken into consideration for the start-up of the fuel cell system 210 when the vehicle 200 is switched on, and in particular, a start-up process of the fuel cell system 210 is defined based on the determined information in order to take the determined information into consideration for the start-up of the fuel cell system 210.

[0047] It may be advantageous in the method if, in particular, a measurement signal of varying frequency is applied 401, in particular a measurement signal of varying frequency between 100 kHz and 1 Hz, preferably between 50 kHz and 100 Hz, to determine at least a plurality of impedance values. Furthermore, it may be advantageous in the method if, in particular from the determined impedance values, an ohmic loss and / or a proton transport resistance of at least one stack part of a fuel cell stack 100 of the fuel cell system 210 is determined 430. From the (determined) ohmic loss, a membrane state and / or an electrical resistance state can be determined 440 as information relating to at least one stack part of a fuel cell stack 100 of the fuel cell system 210, for example by comparing the (determined) ohmic loss with reference data. Alternatively or additionally, it is also conceivable to determine 440 from the (determined) proton transport resistance the wetting state of one or more electrodes of the fuel cell stack and / or the chemical degradation state of one or more ionomers of the fuel cell stack as information relating to at least one stack portion of the fuel cell stack 100 of the fuel cell system 210, for example by comparing the (determined) proton transport resistance with reference data.

[0048] Furthermore, in the method, it may be advantageous if the temperature of at least one of the fuel cell stacks 100 is detected and stored 310 in a specific time range (just before switching off), particularly before switching off the vehicle 200, and / or the power called out from the fuel cell stack 100 is detected and stored 310 in a specific time range (just before switching off), particularly before switching off the vehicle 200, and the detected temperature of the fuel cell stack 100 and / or the detected power called out from the fuel cell stack 100 is taken into account for determining information relating to at least one stack part of the fuel cell stack 100 of the fuel cell system 210.

[0049] Furthermore, it may be advantageous if the method is executed multiple times in succession in the continuously sustained switched-off state of the vehicle 200 after the vehicle 200 is switched off, in particular multiple times at specific time intervals in succession in succession in the same time.

[0050] Further, in the method, it may be advantageous if reference data is stored on the vehicle 200 and / or in the cloud, and the reference data is used to determine, in particular recall, information relating to at least one stack portion of the fuel cell stack 100 of the fuel cell system 210 based on the applied measurement signals and the detected signal responses.

[0051] Furthermore, it may be advantageous in the method, in particular, if information about the complete fuel cell stack 100 of the fuel cell system 210, i.e., in particular, information about the entire fuel cell stack 100, is determined 441 based on the applied measurement signals and the detected signal responses, and / or if information is determined 442 for each of a plurality of stack parts of the fuel cell stack 100 of the fuel cell system 210 based on the respective applied measurement signals and the respective detected signal responses.

[0052] Furthermore, it may be advantageous if the method displays 450 messages, particularly to occupants of the vehicle 200, depending on the determined information.

[0053] 2 discloses a vehicle 200 designed to execute the method according to the invention (see, for example, FIG. 1 in this regard) for determining information about at least one stack part of a fuel cell stack 100 of a fuel cell system 210 of the vehicle 200 after switching off the vehicle 200. The vehicle 200 comprises a recognition device 220 for recognizing a switch-off command for switching off the vehicle 200. The vehicle 200 further comprises a fuel cell system 210 having a fuel cell stack 100 (for clarity, only the fuel cell stack 100 is shown), the cathode region K of the fuel cell stack 100 being fluidically isolable by a cathode gas inlet valve and a cathode gas outlet valve, and the anode region A of the fuel cell stack 100 being fluidically isolable by an anode gas inlet valve and an anode gas outlet valve. The vehicle 200 further comprises an electrical load device 230 accessible to at least one stack part of the fuel cell stack 100, thereby being able to call up power or electrical energy from the fuel cell stack 100. Furthermore, the vehicle 200 comprises an (electrical) applying device 240 for applying an electrical measurement signal to at least one stack portion of the fuel cell stack 100. Furthermore, the vehicle 200 comprises a detecting device 250 for detecting a signal response to the applied electrical measurement signal. Furthermore, the vehicle 200 comprises a determining device 260 for determining information relating to at least one stack portion of the fuel cell stack 100 of the fuel cell system 210 based on the applied measurement signal and the detected signal response. [Explanation of symbols]

[0054] 100 fuel cell stack 200 vehicles 210 Fuel Cell System 230 Electrical Load Device 240 Applicator 250 Detection Device 260 Determination device A Anode region K cathode region

Claims

1. 1. A method for determining information about at least one stack part of a fuel cell stack (100) of a fuel cell system (210) of a vehicle (200) after switching off the vehicle (200), comprising: - recognizing (320) a switch-off command for switching off said vehicle (200); - if the switch-off command is recognized, closing (341) the cathode gas inlet valve of the fuel cell system (210) and closing (342) the cathode gas outlet valve of the fuel cell system (210) in order to fluidically isolate the cathode area (K) of the fuel cell stack (100) in which an air mixture is present, - connecting (360) an electrical load (230) to at least one stack section of the fuel cell stack (100) in order to reduce the proportion of oxygen in the air mixture in the blocked cathode region (K) of the fuel cell stack (100), at least until a predetermined target voltage is recognized (370); - when the predetermined target voltage is recognized, closing (381) the anode gas inlet valve of the fuel cell system (210) and closing (382) the anode gas outlet valve of the fuel cell system (210) in order to fluidically isolate the anode area (A) of the fuel cell stack (100) in which the fuel mixture is present; - applying (400) an electrical measurement signal to at least one stack part of the fuel cell stack (100), in particular when the anode gas inlet valve and the anode gas outlet valve are closed; - detecting (420) a signal response to said applied electrical measurement signal; - determining (440) information relating to at least one stack portion of the fuel cell stack (100) of the fuel cell system (210) based on the applied measurement signal and the detected signal response.

2. 2. The method according to claim 1, characterized in that a measurement signal of varying frequency is applied (401), in particular a measurement signal of varying frequency between 100 kHz and 1 Hz, preferably between 50 kHz and 100 Hz, for determining at least a plurality of impedance values.

3. From the determined impedance value, an ohmic loss and / or proton transport resistance of the at least one stack section of the fuel cell stack of the fuel cell system is determined (430); In particular from the ohmic losses, a membrane state and / or an electrical resistance state is determined (440) as information relating to at least one stack part of the fuel cell stack (100) of the fuel cell system (210), and / or the method according to claim 2, characterized in that, in particular from the proton transport resistance, the wetness state of the electrodes and / or the chemical degradation state of the ionomer are determined (440) as information relating to at least one stack part of the fuel cell stack (100) of the fuel cell system (210).

4. 4. The method according to claim 1, wherein at least one temperature of the fuel cell stack (100) is detected and stored (310) for a specific time range before the vehicle (200) is switched off and / or the power drawn from the fuel cell stack (100) is detected and stored (310) for a specific time range before the vehicle (200) is switched off, and the detected temperature of the fuel cell stack (100) and / or the detected power drawn from the fuel cell stack (100) are taken into account for determining information relating to at least one stack part of the fuel cell stack (100) of the fuel cell system (210).

5. 5. The method according to claim 1, wherein the method is executed multiple times in succession in a continuously sustained switched-off state of the vehicle (200) after the vehicle (200) is switched off, in particular multiple times at specific time intervals in succession in a continuous switched-off state of the vehicle (200).

6. 6. The method according to claim 1, wherein reference data is stored in the vehicle (200) and / or reference data is stored in a cloud, and the reference data is used to determine information about at least one stack part of the fuel cell stack (100) of the fuel cell system (210) based on the applied measurement signals and the detected signal responses.

7. 7. The method according to claim 1, wherein information about the complete fuel cell stack (100) of the fuel cell system (210) is determined (441) based on the applied measurement signals and the detected signal responses, and / or information about each of a plurality of stack parts of the fuel cell stack (100) of the fuel cell system (210) is determined (442) based on the respective applied measurement signals and the respective detected signal responses.

8. 8. The method according to any one of claims 1 to 7, characterized in that a message is displayed (450) to an occupant of the vehicle (200) in response to the determined information.

9. 9. The method according to claim 1, wherein the information determined after the switching off of the vehicle (200) is taken into account for the start-up of the fuel cell system (210) when the vehicle (200) is switched on, and in particular, a start-up process of the fuel cell system (210) is defined based on the determined information in order to take the determined information into account for the start-up of the fuel cell system (210).

10. A vehicle (200) designed to perform a method for determining information about at least one stack part of a fuel cell stack (100) of a fuel cell system (210) of the vehicle (200) after switching off the vehicle (200) according to any one of claims 1 to 9, the vehicle (200) comprising: a recognition device (220) for recognizing a switch-off command for switching off said vehicle (200); a fuel cell system (210) having a fuel cell stack (100), the cathode region (K) of which can be fluidically isolated by a cathode gas inlet valve and a cathode gas outlet valve, and the anode region (A) of which can be fluidically isolated by an anode gas inlet valve and an anode gas outlet valve; an electrical load (230) contactable with at least one stack section of the fuel cell stack (100); an application device (240) for applying an electrical measurement signal to at least said at least one stack part of said fuel cell stack (100); a detection device (250) for detecting a signal response to said applied electrical measurement signal; - a determination device (260) for determining information relating to at least one stack portion of the fuel cell stack (100) of the fuel cell system (210) based on the applied measurement signal and the detected signal response.

11. A computer program product comprising instructions causing a vehicle (200), in particular a vehicle (200) according to claim 10, to perform the method steps according to the method according to any one of claims 1 to 9.

12. A computer readable medium having stored thereon the computer program product of claim 11.

13. A data carrier signal carrying a computer program product according to claim 11.

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