OPERATING DEVICE, FUEL CELL SYSTEM, MOTOR VEHICLE AND METHOD FOR OPERATING A FUEL CELL SYSTEM

Description

[0001] The present invention relates to an operating device for operating a fuel cell, comprising a voltage monitoring module for monitoring the cell voltage of the fuel cell and a control module for controlling the operation of the fuel cell. Furthermore, the invention relates to a fuel cell system for providing electrical energy with an operating device according to the invention, a motor vehicle with a fuel cell system according to the invention, and a method for operating a fuel cell system according to the invention.

[0002] Fuel cell systems are known in the art in a wide variety of different designs. These systems often include sensors for measuring operating parameters such as voltage, current, temperature, humidity, or pressure. If an operating parameter deviates from a predefined range, thereby jeopardizing the operational safety of the fuel cell, the fuel cell must usually be shut down or at least its output reduced.

[0003] Key operating parameters of a fuel cell are the characteristics of the individual cell voltages within the fuel cell stack. Fuel cell systems typically include a monitoring module to track the cell voltage over time. If the cell voltage deviates from a predefined voltage range during a fuel cell operating mode—for example, during startup, continuous operation, or shutdown—such as falling below, exceeding, or being too high or too low on average, an unfavorable operating condition may exist for the fuel cell. This can negatively impact its lifespan, operational reliability, or other aspects.

[0004] JP 2017 152 134 A relates to a fuel cell system with a fuel cell stack consisting of several fuel cells, a residue detection device for determining hydrogen residues in the fuel cell stack during system start-up, a Cell Voltage Monitoring (CVM) unit for determining the electrical voltages of the individual fuel cells, a main switch for electrically switching the fuel cell stack on and off, a determination unit for determining whether the voltages are within predefined limits, and a main switch control unit for controlling the hydrogen supply to the fuel cell stack based on the determined voltages. Accordingly, operating points of the fuel cell system are determined based on voltage monitoring of the fuel cell system using the CVM unit and taking into account the operating state of the fuel cell system.

[0005] From US patent 2018 026 286 A1, a fuel cell system is known, comprising a fuel supply device, an air supply device with an air mass measuring device, a voltage measuring device for measuring the electrical voltage of the fuel cells, and a control device. The control device is configured to control the fuel supply device for supplying the fuel cell during startup over a first time interval. Furthermore, the control device is configured to control the air supply device for supplying the fuel cell with air over a second time interval after the first time interval has elapsed. The control device is also configured to determine the amount of air supplied during the second time interval and to compare it with a limit value, and to initiate an action when the limit value is reached or exceeded.The device compares the output voltage of the fuel cells with a predetermined output voltage if the air limit is exceeded. Finally, the monitoring device is designed to detect an anomaly in the fuel cells if the predetermined output voltage is undershot.

[0006] EP 3 038 199 A1 discloses a fuel cell system comprising a fuel cell, a temperature sensor for measuring the temperature of the fuel cell, and a control device for causing the fuel cell to increase the relative humidity within the fuel cell by lowering its temperature. Furthermore, the fuel cell system includes an impedance meter for measuring the impedance of the fuel cell, the control device being configured to modify the water balance depending on the measured impedance when the measured impedance reaches or falls below a specified impedance threshold.

[0007] Similar systems and methods are disclosed by DE 10 2015 221840 A1 and EP 2 052 429 A2.

[0008] Known fuel cell systems and methods for operating fuel cells have the disadvantage that they essentially only determine the "State of Operation" (SOO) of the fuel cell. If an operating parameter limit is exceeded or fallen below, the fuel cell usually has to be shut down. This has a particularly negative impact on the reliability of the fuel cell, as it is unavailable to provide electrical energy when shut down.

[0009] Therefore, the object of the present invention is to at least partially address the problem described above. In particular, the object of the present invention is to provide an operating device for operating a fuel cell, a fuel cell system, a motor vehicle, and a method for operating a fuel cell system, which can improve the operation of the fuel cell and at least partially prevent a forced shutdown of the fuel cell using simple means and in a cost-effective manner.

[0010] The aforementioned problem is solved by the claims. In particular, the aforementioned problem is solved by the operating device for operating a fuel cell according to claim 1, the fuel cell system for providing electrical energy according to claim 7, the motor vehicle according to claim 8, and the method for operating a fuel cell system according to claim 9. Further advantages of the invention will become apparent from the dependent claims, the description, and the drawings. Features and details described in connection with the operating device according to the invention naturally also apply in connection with the fuel cell system, the motor vehicle, and the method for operating a fuel cell system according to the invention, and vice versa, so that the disclosure regarding the individual aspects of the invention always includes, or allows for, reciprocal reference.

[0011] According to the first aspect of the present invention, the problem is solved by an operating device for operating a fuel cell. The operating device comprises a voltage monitoring module for monitoring the cell voltage of the fuel cell and a control module for controlling the operation of the fuel cell. According to the invention, the operating device comprises a storage module for storing a cell voltage matrix and a comparison module for comparing an operating mode of the fuel cell and the monitored cell voltage with the cell voltage matrix in order to determine at least one specific countermeasure for influencing the cell voltage of the fuel cell from the cell voltage matrix. The control module comprises reaction means for controlling the operation of the fuel cell based on the determined at least one specific countermeasure.

[0012] The operating device is designed to operate the fuel cell. Accordingly, operating parameters of the fuel cell, such as hydrogen mass flow, air mass flow, humidifier bypass, or the like, can be specifically influenced or controlled by the operating device, in particular by means of the reaction agents of the control module of the operating device. The operating device is preferably designed to control and / or regulate the fuel cell.

[0013] The voltage monitoring module is designed to monitor the cell voltage of the fuel cell. For this purpose, the voltage monitoring module preferably includes a voltage measuring device for determining the cell voltage of the fuel cell over a period of time. Thus, the voltage monitoring module can be used to determine, for example, the average cell voltage and / or minimum and maximum cell voltage of the fuel cell stack over this period. The voltage monitoring module is also designed to provide the cell voltages determined by the voltage monitoring module, in particular the average cell voltage and / or minimum and maximum cell voltage, to the comparison module. Alternatively, the voltage monitoring module can be configured to determine and forward the cell voltages to the comparison module, which is then configured to determine or calculate the average cell voltage from this data.

[0014] The storage module is configured to store the cell voltage matrix. Preferably, the cell voltage matrix is ​​already stored in the storage module. Several different signal response matrices can also be stored in the storage module, with the comparison module preferably configured to select the cell voltage matrix to be used, for example, depending on the operating history of the fuel cell, the wear state of the fuel cell, the total operating time of the fuel cell, a user setting, or the like. The cell voltage matrix is ​​a matrix in which at least one specific countermeasure is defined for a pairing of a fuel cell operating mode with a cell voltage, in particular an average cell voltage and / or maximum and minimum cell voltage.The specific countermeasures are preferably designed to influence the cell voltage of the fuel cell. Influencing the cell voltage is understood in particular to mean ensuring that the cell voltage remains within a predetermined range. This not only ensures a predefined cell voltage but also reduces wear on the fuel cell.

[0015] According to the invention, the fuel cell can successively cycle through different operating modes. Operating modes of a fuel cell system include, for example, startup, normal operation, and shutdown. Preferably, the comparison module is designed to determine, and in particular to determine independently, the current operating mode.

[0016] The control module is designed to monitor the operation of the fuel cell. Furthermore, the control module contains the reactive means to intervene in the operation of the fuel cell based on at least one identified specific countermeasure.

[0017] The operating device is preferably designed to operate the fuel cell automatically, enabling automatic monitoring of the cell voltage, determination of the current operating mode, control of the fuel cell's operation, identification, and implementation of appropriate specific countermeasures. Thus, the operating device is designed to continuously react to changes in the cell voltage in order to reduce these deviations.

[0018] The operating device according to the invention for operating a fuel cell has the advantage over conventional operating devices that, using simple means and in a cost-effective manner, specific countermeasures can be identified based on determined cell voltages and the current operating mode of the fuel cell, by means of which the cell voltage of the fuel cell can be advantageously changed. With the operating device according to the invention, a rapid response to fluctuations in the cell voltage can thus be achieved, thereby ensuring longer and more robust operation of the fuel cell.

[0019] According to the invention, an operating device is provided with a voltage monitoring module designed to determine an average cell voltage across all individual cell voltages, as well as to determine the maximum and minimum cell voltages within a predefined period. The average cell voltage, as well as the maximum and minimum cell voltages, are advantageous indicators for the operating state of the fuel cell. Based on these indicators, it can be assessed whether the fuel cell, in its current operating mode, exhibits a normal or non-critical operating state, a still acceptable operating state, or a critical operating state.This has the advantage that the operating device is designed with simple means and in a cost-effective manner, and that, based on the determined cell voltage and the operating mode, a particularly suitable countermeasure for influencing the cell voltage can be identified and implemented using the cell voltage matrix.

[0020] It is preferred that the cell voltage matrix has several operating modes, with each operating mode being assigned several cell voltage classes, and with each cell voltage class being assigned at least one specific countermeasure for influencing the cell voltage of the fuel cell. The operating modes preferably include a start-up and / or normal operation and / or a shutdown of the fuel cell. The individual cell voltage classes preferably comprise one or more cell voltage statements. A cell voltage statement is, for example, the level of an average cell voltage across all current individual cell voltages. Accordingly, a cell voltage class can be defined by a single cell voltage statement or a combination of several cell voltage statements. A combination of several cell voltage statements can, for example, include an AND operation or an OR operation of the cell voltage statements.Based on the monitored cell voltage and the determined operating mode, a specific cell voltage class can be identified within the cell voltage matrix. Each cell voltage class is assigned at least one specific countermeasure for influencing the fuel cell's cell voltage, meaning that one or more potential specific countermeasures are defined for a given cell voltage class. This has the advantage of improving the identification of a suitable specific countermeasure using simple and cost-effective methods.

[0021] Particularly preferably, each cell voltage class exhibits at least one of the following cell voltage statements: Average cell voltage over a given period, a minimum cell voltage over a predefined period, a maximum cell voltage over the predefined period, exceeding a given maximum cell voltage in the given period, falling below a given minimum cell voltage in the given period.

[0022] The average cell voltage can be easily determined by monitoring the cell voltage, in particular by continuously measuring and averaging the individual cell voltages. This cell voltage statement can be further specified, such that the average cell voltage corresponds to, exceeds, or falls below a predetermined average cell voltage value. Within the scope of the invention, the cell voltage statement "minimum cell voltage over a predefined period" means that a defined lower limit value for the cell voltage is undershot over the predefined period. Therefore, falling below the lower limit value is only significant if it persists for at least the predefined period.Accordingly, within the scope of the invention, the cell voltage statement "maximum cell voltage over a predefined period" is understood to mean that a defined upper limit of the cell voltage is exceeded over the predefined period. Exceeding the upper limit is therefore only significant if it persists for at least the predefined period. However, when the predetermined maximum cell voltage is exceeded or the predetermined minimum cell voltage is undershot, it is sufficient for this state to exist for only a moment to fulfill the respective cell voltage statement. Therefore, the maximum cell voltage is greater than the upper limit, and the minimum cell voltage is less than the lower limit.Using these cell voltage statements in conjunction with the operating modes of the fuel cell, cell voltage classes can be advantageously defined which are particularly suitable for characterizing operating states of the fuel cell, so that on this basis the identification of suitable specific countermeasures is improved.

[0023] Preferably, the cell voltage matrix for at least one operating state class includes several different specific countermeasures. This takes into account the fact that various specific countermeasures may be suitable for influencing the cell voltage of the fuel cell. For example, if there is a minimum cell voltage over a predefined period and a certain average cell voltage over a specified period that is above a predetermined average cell voltage value, a specific countermeasure can be identified by which the cell voltage can be increased. This has the advantage that influencing the cell voltage of the fuel cell can be optimized using simple means and in a cost-effective manner.

[0024] Preferably, the various specific countermeasures within an operating state class are hierarchically structured in the cell voltage matrix. Based on this hierarchical structure, the specific countermeasures can be selected and implemented successively. If the operating state class does not improve after implementing a highest-level specific countermeasure, the next specific countermeasure in the hierarchy can be selected and implemented, and so on. The operating device is thus designed to react appropriately to unexpected events, such as an insufficient increase in cell voltage following the implementation of a specific countermeasure, in order to always influence the fuel cell cell voltage in a moderate manner.

[0025] According to the invention, the cell voltage matrix may include at least one of the following specific countermeasures: Increasing the fuel cell pressure, reducing the fuel cell pressure, increasing the fuel cell temperature, reducing the fuel cell temperature, increasing the fuel cell humidity, reducing the fuel cell humidity, increasing the fuel cell anode fluid flow rate, reducing the fuel cell anode fluid flow rate, reducing the fuel cell cathode fluid flow rate (cathode stoichiometry), increasing the fuel cell cathode fluid flow rate (cathode stoichiometry).

[0026] The cell voltage of the fuel cell can be directly influenced by means of these specific countermeasures. These specific countermeasures are assigned to the individual cell voltage classes, whereby a cell voltage class can have one or more specific countermeasures. Thus, the cell voltage matrix defines which specific countermeasures can be implemented for each cell voltage class to influence the cell voltage of the fuel cell, for example, to increase the cell voltage, particularly during the fuel cell's start-up phase.

[0027] According to the second aspect of the invention, the problem is solved by a fuel cell system for providing electrical energy. The fuel cell system comprises a fuel cell and an operating device according to the invention for operating the fuel cell. The fuel cell is preferably designed according to a conventional fuel cell with a membrane, an anode, a cathode, a fuel supply, an oxygen supply, and a water discharge. Preferably, the fuel cell system comprises several fuel cells, with one operating device preferably designed and configured for operating several fuel cells. Additionally, the fuel cell system may comprise several operating devices according to the invention, each designed and configured for operating one or more fuel cells.

[0028] Thus, a fuel cell system according to the invention offers the same advantages as those described in detail with reference to the operating device according to the invention. Accordingly, the fuel cell system according to the invention has the advantage over conventional fuel cell systems that, using simple means and in a cost-effective manner, specific countermeasures can be identified based on determined cell voltages and the current operating mode of the individual fuel cells, by means of which the cell voltages of the fuel cells can be advantageously modified. With the fuel cell system according to the invention, a rapid response to fluctuations in the cell voltages can therefore be achieved, thus ensuring longer and more robust operation of the individual fuel cells.

[0029] According to the third aspect of the invention, the problem is solved by a motor vehicle with a fuel cell system according to the invention for providing electrical energy and at least one electric motor for driving the motor vehicle, using at least some of the electrical energy provided by the fuel cell system. Preferably, the motor vehicle has at least one battery for storing or temporarily storing the electrical energy provided by the fuel cell system.

[0030] Thus, a motor vehicle according to the invention offers the same advantages as those described in detail with reference to the operating device and the fuel cell system according to the invention. Accordingly, the motor vehicle according to the invention has the advantage over conventional motor vehicles that, using simple means and in a cost-effective manner, specific countermeasures can be identified based on determined cell voltages and the current operating mode of the individual fuel cells, by means of which the cell voltages of the fuel cells can be advantageously modified. With the motor vehicle according to the invention, a rapid response to fluctuations in the cell voltages can therefore be achieved, thus ensuring longer and more robust operation of the individual fuel cells.

[0031] According to the fourth aspect of the invention, the problem is solved by a method for operating a fuel cell system according to the invention. The method comprises the following steps: Determining the current characteristics of the cell voltages of the fuel cells or the fuel cell stack, in particular over a specified period, using the voltage monitoring module of the operating device; determining an operating mode of the fuel cell using the control module of the operating device; comparing the determined cell voltages and the determined operating mode with a cell voltage matrix stored in the storage module to identify a specific countermeasure to influence the cell voltage of the fuel cell using the comparison module; and generating a control intervention in the operation of the fuel cell based on the identified specific countermeasure using the control module.

[0032] The cell voltages of the fuel cell are determined using the voltage monitoring module. For this purpose, the voltage monitoring module preferably includes a voltage measurement module for measuring the cell voltage. The cell voltages are preferably determined continuously or intermittently, particularly at regular, preferably high-frequency, time intervals. In this way, for example, an average current cell voltage can be determined, especially over a specified period.

[0033] Furthermore, the control module determines the operating mode of the fuel cell. Operating modes can include, for example, startup, normal operation, shutdown, or similar functions of the fuel cell.

[0034] The comparison module compares the determined cell voltages and the specified operating mode with the cell voltage matrix stored in the storage module in order to identify at least one specific countermeasure for influencing the fuel cell's cell voltage. For example, a specific cell voltage class is first identified based on the determined cell voltages. The cell voltage classes are listed in the cell voltage matrix. Furthermore, one or more specific countermeasures are assigned to each cell voltage class. According to the invention, a specific countermeasure may define a non-intervention in the operation of the fuel cell. This specific countermeasure is, for example, assigned to a cell voltage class that represents normal operation of the fuel cell as intended, without significant deviations in cell voltage.By identifying a specific cell voltage class, at least one specific countermeasure is also identified using the cell voltage matrix.

[0035] Based on the identified specific countermeasure, the control module, in particular the control module's reaction agent, initiates the control intervention in the fuel cell's operation. The specific countermeasure is thus implemented. If the specific countermeasure is successfully implemented, the cell voltage is modified such that the cell voltage values ​​are at least closer to a target cell voltage value than before the inventive method was implemented. By iteratively implementing the inventive method, particularly with modified, preferably weakened, specific countermeasures, the fuel cell's operation can therefore be continuously improved.

[0036] Thus, a method according to the invention offers the same advantages as those described in detail with reference to the operating device according to the invention. Accordingly, the method according to the invention has the advantage over conventional methods that, using simple means and in a cost-effective manner, specific countermeasures can be identified and implemented based on determined cell voltages and the current operating mode of the individual fuel cells, in order to advantageously modify the cell voltages of the fuel cells. The method according to the invention thus ensures a rapid response to fluctuations in cell voltages and therefore guarantees longer and more robust operation of the individual fuel cells.

[0037] It is preferred that, when comparing the determined cell voltages with the cell voltage matrix, a cell voltage class defined in the cell voltage matrix is ​​selected based on at least one of the following cell voltage statements: Average cell voltage determined over a specified period, maximum cell voltage determined over a predefined period, minimum cell voltage determined over a predefined period, exceeding a specified maximum cell voltage value, falling below a specified minimum cell voltage value, The specific countermeasure is identified, which is assigned to the same cell voltage class in the cell voltage matrix. The cell voltage matrix has several cell voltage classes, each with one or more specific countermeasures assigned to it. Using such cell voltage statements, a cell voltage class can be identified that characterizes a fuel cell operating state particularly accurately. In conjunction with the determined operating mode, a reliable identification of a suitable specific countermeasure for influencing the fuel cell cell voltage is thus ensured using simple and cost-effective means.

[0038] According to an advantageous embodiment of the invention, the cell voltages of the fuel cell are repeatedly determined over a further predetermined period, and an updated operating mode is re-determined. Based on the repeatedly determined cell voltages, and with the operating mode unchanged, the cell voltage class is repeatedly determined. If the cell voltage class changes, an updated specific countermeasure is identified from the cell voltage matrix, and the fuel cell is controlled by the control module based on the identified updated specific countermeasure. The method is therefore preferably carried out continuously during the operation of the fuel cell.Depending on the degree of reaction of the operating state to the initially implemented specific countermeasure, it can be determined whether the current intensity of this countermeasure is sufficient to adequately influence the cell voltage. If it is found that the degree of reaction is too low, i.e., the predetermined minimum influence is not reached, the intensity of the specific countermeasure can be increased, for example, to achieve a greater influence on the fuel cell's cell voltage. Alternatively, another specific countermeasure, particularly from the same cell voltage class, can be identified and implemented. This has the advantage that the effects of the countermeasures can be monitored, and if the influence on the cell voltage is insufficient, the countermeasures can be implemented in a modified form.

[0039] Preferably, the specific countermeasure includes one or more of the following: Increasing the fuel cell pressure, reducing the fuel cell pressure, increasing the fuel cell temperature, reducing the fuel cell temperature, increasing the fuel cell humidity, reducing the fuel cell humidity, reducing the fuel cell anode fluid flow, increasing the fuel cell anode fluid flow, reducing the fuel cell cathode fluid flow (cathode stoichiometry), increasing the fuel cell cathode fluid flow (cathode stoichiometry).

[0040] The cell voltage of the fuel cell can be directly influenced by these specific countermeasures. These countermeasures are assigned to individual cell voltage classes, with each cell voltage class having one or more specific countermeasures. Thus, the cell voltage matrix defines which specific countermeasures can be implemented for each cell voltage class to influence the cell voltage of the fuel cell, for example, to reduce the deviation between the minimum and average cell voltage, particularly during fuel cell startup.

[0041] Further improvements to the invention will become apparent from the following description of various embodiments of the invention, which are schematically illustrated in the figures. The figures schematically show: Figure 1 shows a preferred embodiment of a fuel cell system according to the invention, Figure 2 shows a side view of a preferred embodiment of a motor vehicle according to the invention, Figure 3 shows a preferred cell voltage matrix for the "Start Up" operating mode, Figure 4 shows a preferred cell voltage matrix for the "Full Run" operating mode, Figure 5 shows a preferred cell voltage matrix for the "Shutdown" operating mode, and Figure 6 shows a flowchart illustrating a preferred embodiment of the method according to the invention.

[0042] Elements with the same function and mode of operation are each provided with the same reference symbols in Figures 1 to 8.

[0043] In Fig. 1A preferred embodiment of a fuel cell system 10 according to the invention is shown schematically. The fuel cell system 10 comprises a fuel cell 2 for generating electric current and an operating device 1 for operating the fuel cell 2. The operating device 1 includes a voltage monitoring module 3 for monitoring the cell voltage of the fuel cell 2, a control module 4 for monitoring the operation and for determining an operating mode of the fuel cell 2, a storage module 5 for storing a cell voltage matrix, and a comparison module 6 for comparing the operating mode of the fuel cell 2 and the monitored cell voltage with the cell voltage matrix in order to determine at least one specific countermeasure for influencing the cell voltage of the fuel cell 2.Additional sensors and modules, such as temperature sensors, pressure sensors, humidity sensors, dehumidification modules, or similar devices, may be provided.

[0044] Fig. 2 Figure 1 schematically shows a preferred embodiment of a motor vehicle 11 according to the invention in a side view. The motor vehicle 11 has an electric motor 12, which is designed to drive the motor vehicle 11. Furthermore, the motor vehicle 11 has a fuel cell system 10 according to the invention for providing electrical energy.

[0045] In Figs. 3 to 5 Preferred signal response matrices for the operating modes "Start Up," "Full Run," and "Shutdown" are shown. The signal response matrices exhibit several cell voltage classes for each operating mode, which are listed in the column labeled "Range."

[0046] The cell voltage matrix is ​​explained in more detail below using examples. The cell voltage matrix consists of Fig. 3 This concerns the start-up of fuel cell 2. If the voltage is at least 0.3V for a minimum of 5 seconds and the average voltage is below 0.8V, the middle cell voltage class in the "Range" column is selected. Feasible specific countermeasures for influencing the fuel cell voltage are listed in the row of the selected cell voltage class. Accordingly, the cell voltage matrix specifies, for example, a reduction in electrical current, an increase in anode mass current, and an increase in the fuel cell pressure as specific countermeasures.

[0047] The cell voltage matrix from Fig. 4This applies to normal operation of fuel cell 2. If the maximum cell voltage exceeds 0.85V, the cell voltage class labeled "UCellMax over 0.85V" in the "Range" column is selected. Feasible specific countermeasures for influencing the fuel cell voltage are listed in the row of the selected cell voltage class. For example, the cell voltage matrix specifies increasing the fuel cell current as a specific countermeasure.

[0048] The cell voltage matrix from Fig. 5This concerns fuel cell shutdown 2. At a high voltage above 0.85V, the second cell voltage class from the bottom is selected. This line includes, as feasible specific countermeasures to influence the fuel cell voltage, a reduction in the cathode mass current and a reduction in the electrical current. At a minimum cell voltage of 0.3V for 5s and an average cell voltage below 0.8V, the second cell voltage class from the top is selected. Associated specific countermeasures include, for example, a reduction in the electrical current, an increase in the anode mass current, or an increase in the cathode mass current.

[0049] A preferred embodiment of a method according to the invention is in Fig. 6This process is illustrated in a flowchart. In a first process step 100, the voltage monitoring module 3 of the operating device 1 determines the cell voltages of the fuel cell 2 over a predefined period. In a second process step 200, the control module 4 of the operating device 1 determines an operating mode of the fuel cell 2. In a third process step 300, the comparison module 6 of the operating device 1 compares the determined cell voltages and the determined operating mode with a cell voltage matrix stored in the storage module 5. In this way, the comparison module 6 identifies a specific countermeasure to influence the cell voltage of the fuel cell 2. In a fourth process step 400, the control module 4 initiates a control intervention in the operation of the fuel cell 2 based on the identified specific countermeasure.This means that the identified countermeasure to influence the cell voltage is implemented.

[0050] The invention allows for further design principles in addition to those illustrated. That is to say, the invention should not be considered limited to the exemplary embodiments explained with reference to the figures. Reference symbol list

[0051] 1 Operating device 2 Fuel cell 3 Voltage monitoring module 4 Control module 5 Storage module 6 Comparator module 10 Fuel cell system 11 Motor vehicle 12 Electric motor 100 first process step 200 second process step 300 third process step 400 fourth process step

Claims

1. Operating device (1) for operating a fuel cell (2), comprising a voltage monitoring module (3) for monitoring a cell voltage of the fuel cell (2) and a control module (4) for controlling the operation of the fuel cell (2), wherein the operating device (1) comprises a storage module (5) for storing a cell voltage matrix and a comparison module (6) for comparing an operating mode of the fuel cell (2) and the monitored cell voltage with the cell voltage matrix to determine at least one specific countermeasure for influencing the cell voltage of the fuel cell (2) from the cell voltage matrix, wherein the control module (4) comprises reaction means for a control intervention in the operation of the fuel cell (2) based on the at least one determined specific countermeasure, characterized in that the voltage monitoring module (3) is configured to determine an average cell voltage over a predetermined period as well as to determine a maximum cell voltage and minimum cell voltage within the predefined period. is.

2. Operating device (1) according to claim 1, characterized in that the cell voltage matrix comprises several operating modes, each operating mode being assigned several cell voltage classes, and each cell voltage class being assigned at least one specific countermeasure for influencing the cell voltage of the fuel cell (2).

3. Operating device (1) according to claim 2, characterized in that each cell voltage class has at least one of the following cell voltage statements: • Average cell voltage over a predetermined period, • a minimum cell voltage over a predetermined period, • a maximum cell voltage over the predetermined period, • exceeding a predetermined maximum cell voltage within the predetermined period, • falling below a predetermined minimum cell voltage within the predetermined period.

4. Operating device (1) according to claim 2 or 3, characterized in that the cell voltage matrix comprises several different specific countermeasures for at least one cell voltage class.

5. Operating device (1) according to claim 4, characterized in that the different specific countermeasures within a cell voltage class are hierarchically structured in the cell voltage matrix.

6. Operating device (1) according to one of claims 2 to 5, characterized in that the cell voltage matrix comprises at least one of the following specific countermeasures: • Increasing the cell pressure of the fuel cell (2), • Reducing the cell pressure of the fuel cell (2), • Increasing the cell temperature of the fuel cell (2), • Reducing the cell temperature of the fuel cell (2), • Increasing the cell humidity of the fuel cell (2), • Reducing the cell humidity of the fuel cell (2). • Increasing the anode operating current of the fuel cell (2), • Reducing the anode operating current of the fuel cell (2), • Reducing the cathode operating current of the fuel cell (2), • Increasing the cathode operating current of the fuel cell (2).

7. Fuel cell system (10) for providing electrical energy, comprising a fuel cell (2) and an operating device (1) for operating the fuel cell (2), characterized in that the operating device (1) is configured according to any one of claims 1 to 6.

8. Motor vehicle (11) with a fuel cell system (10) according to claim 7 for providing electrical energy and at least one electric motor (12) for driving the motor vehicle (11) using at least some of the electrical energy provided by the fuel cell system (10).

9. Method for operating a fuel cell system (10) according to claim 7, comprising the following steps: • Determining the current characteristics of the cell voltages of the fuel cells (2) using the voltage monitoring module (3) of the operating device (1), • Determining an operating mode of the fuel cell (2) using the control module (4) of the operating device (1), • Comparing the determined cell voltages and the determined operating mode with a cell voltage matrix stored in the storage module (5) to identify a specific countermeasure for influencing the cell voltage of the fuel cell (2) using the comparison module (6), and • Generating a control intervention in the operation of the fuel cell (2) based on the identified specific countermeasure using the control module (4), characterized in that, when comparing the determined cell voltages with the cell voltage matrix, a cell voltage class defined in the cell voltage matrix is selected based on at least one of the following cell voltage statements: • via a Average cell voltage determined over a predefined period • maximum cell voltage determined over a predefined period • minimum cell voltage determined over a predefined period, • exceeding a predefined maximum cell voltage value, • falling below a predefined minimum cell voltage value, whereby the specific countermeasure is identified which is assigned to the same cell voltage class in the cell voltage matrix.

10. Method according to claim 9, characterized in that the voltage monitoring module (3) is used to repeatedly determine the cell voltages of the fuel cell (2) over a further predefined period and to repeatedly determine an updated operating mode, wherein, based on the repeatedly determined cell voltages with an unchanged operating mode, the cell voltage class is repeatedly determined, wherein, with an unchanged cell voltage class, at least one further specific countermeasure is identified according to a hierarchy specified in the cell voltage matrix and is successively implemented depending on a change in the cell voltage class.

11. Method according to claim 10, characterized in that all specific countermeasures of a cell voltage class according to their hierarchization is carried out successively until the cell voltage can be assigned to a predefined cell voltage class.

12. Method according to one of claims 9 to 11, characterized in that the voltage monitoring module (3) is used to repeatedly determine the cell voltages of the fuel cell (2) over a further predetermined period and to repeatedly determine an updated operating mode, wherein, based on the repeatedly determined cell voltages with an unchanged operating mode, the cell voltage class is repeatedly determined, wherein, if the cell voltage class changes, an updated specific countermeasure is identified from the cell voltage matrix, and wherein the fuel cell (2) is controlled by the control module (4) based on the identified updated specific countermeasure.

13. Method according to any one of claims 9 to 12, characterized in that the specific countermeasure comprises one or more of the following: • Increasing the cell pressure of the fuel cell (2), • Reducing the cell pressure of the fuel cell (2), • Increasing the cell temperature of the fuel cell (2), • Reducing the cell temperature of the fuel cell (2), • Increasing the cell humidity of the fuel cell (2), • Reducing the anode fluid flow rate of the fuel cell (2), • Increasing the anode fluid flow rate of the fuel cell (2), • Reducing the cathode fluid flow rate of the fuel cell (2), • Increasing the cathode fluid flow rate of the fuel cell (2).