Method for operating a fuel cell system

Abstract

The invention relates to a method for operating a fuel cell system (100), in particular of a vehicle (200), by a control unit (FCCU), comprising: providing (110), by means of the control unit (FCCU), a respective heating current ( / i,k) to a heater of a number (n) of heaters of the fuel cell system (100) in a second calculation step (k), wherein the heating currents ( / i k) in total result in an overall heating current (I ges,k); predicting (120), by means of the control unit (FCCU), the overall heating current (I ges,k+i) for a third calculation step (k+1), following the second calculation step (k), in dependence on the overall heating current (I ges,k) of the second calculation step (k); and operating (130), by the control unit (FCCU), the fuel cell system (100) in dependence on the overall heating current (I ges,k+1) of the third calculation step (k+1). The invention also relates to a fuel cell system (100), to a computer program product, to a computer-readable data carrier, to a control unit (FCCU) and to a system (200).

Description

[0001] R.414551 - 1 -Description Title Method for Operating a Fuel Cell System The invention relates to a method with the features of the independent method claim, a fuel cell system with the features of the independent device claim, a computer program product with the features of the independent patent claim relating to a computer program product, a computer-readable data carrier with the features of the independent patent claim relating to a computer-readable data carrier, a control unit with the features of the independent patent claim relating to a control unit, and a system with the features of the independent patent claim relating to a system. Fuel cell systems are known which are used in systems such as (motor) vehicles to provide (electrical) power. The prior art has disadvantages.It is possible that a cold start of such fuel cell systems may not be possible or only possible within certain temperature ranges. For example, a cold start may be impossible, limited, and / or delayed at temperatures below freezing (of water). Components of the fuel cell system may not be fully functional, such as frozen. Heaters (e.g., low-voltage electric heaters) and / or temperature control devices may also be missing or cannot be operated safely. For instance, excessive electrical currents (from the heaters) could cause damage. Furthermore, different heaters may not be able to operate because, for example, the current (consumption) limits of a single heater, particularly the total current, are exceeded.Therefore, certain heaters may not function (directly), which in particular delays the entire period until a (possible) start. Components may include sensors and / or actuators. Sensors may, especially in the case of R.414551-, 2 -At low temperatures, no or incorrect measurement data may be generated, which can prevent (efficient) operation of the fuel cell system. It may also be the case that actuators do not function at all or not as intended (and / or predictably) at low temperatures. Therefore, it is an object of the present invention to overcome at least one of the aforementioned disadvantages, at least partially. In particular, it is an object of the invention to enable faster heating and / or starting of a fuel cell system. It may also be an object to reduce wear and / or increase safety. It may also be provided to enable improved operation and / or heating of one or more heaters.The foregoing problem is solved by a method with the features of the independent method claim, a fuel cell system with the features of the independent device claim, a computer program product with the features of the independent patent claim relating to a computer program product, a computer-readable data carrier with the features of the independent patent claim relating to a computer-readable data carrier, a control unit with the features of the independent patent claim relating to a control unit, and a system with the features of the independent patent claim relating to a system. Further features and details of the invention will become apparent from the dependent claims, the description, and the drawings.Features and details described in connection with the inventive method naturally also apply in connection with the inventive fuel cell system and / or in connection with the inventive computer program product and / or in connection with the inventive computer-readable data carrier and / or in connection with the inventive control unit and / or in connection with the inventive system, and vice versa, so that the disclosure regarding the individual aspects of the invention always refers to each other or can refer to each other. In particular, advantages described in the first, second, third, R.414551- apply. 3 -The above problem is solved according to a first aspect by a method for operating a fuel cell system, in particular a system (according to the sixth aspect) and / or vehicle, by a control unit (according to the fifth aspect), comprising: - Providing, by the control unit, a respective heating current to a heater of a (total) number of heaters of the fuel cell system in a second calculation step, wherein the heating currents (in particular for a respective [first, second and / or third] calculation step) sum to a (respective) total heating current, - Predicting (calculating), by the control unit,of the total heating current for a third calculation step following the second calculation step (temporally and / or directly) as a function of the total heating current of the second calculation step, and in particular the total heating current of a first calculation step, especially one immediately preceding and / or earlier than the second calculation step, and operation, by the control unit, of the fuel cell system as a function of the total heating current of the third calculation step. The method can be (at least partially) computer-implemented. Operation can in particular include control and / or regulation, preferably using a control unit (see below). The described actions or features of the method can be carried out in the sequence shown and in particular can be carried out repeatedly. Preferably, the method can be used toTo control and / or regulate a fuel cell system according to the second aspect. A control unit according to the fifth aspect can particularly preferably be used for (activating) control and / or regulation. The control unit can perform the corresponding actions or features and / or initiate control, preferably to realize the actions. R.414551 -, 4 -The fuel cell system can have at least one, preferably several (in particular a plurality, e.g., 10) heaters. Each heater can be specific for and / or arranged on or in a (functionally essential) component of the fuel cell system (also known as a balance-of-plant [BoP] component), in particular comprising a sensor (e.g., temperature sensor, pressure sensor, mass flow sensor) and / or actuator (e.g., valve, heat exchanger, fan) of the fuel cell system. The heater can, for example, be a foil heater, which is specifically designed to heat a component (e.g., a gas line). Alternatively or additionally, the heater can, for example, be a cartridge heater, which is specifically designed to heat a component. For example, a heating current can be converted into heat resistively or due to ohmic losses in the heater.This allows the heater and / or the component to be heated and / or the temperature of the heater and / or the component to be increased. This allows, for example, a target temperature and / or (desired) operating temperature (of the fuel cell system, the fuel cell stack, and / or the respective components) to be reached. Preferably, this enables defrosting and / or thawing. The calculation steps can be performed by the control unit. These calculation steps can be discrete and / or performed at or for discrete time points, e.g., every 10 ms, by the control unit. Furthermore, heating can be performed in the first, second, third, and / or each calculation step by supplying a total heating current and / or individual heating currents to the heater(s). The profile or...The value is predefined by the control unit and / or transmitted to it (e.g., by a predefined control command). Preferably, the control unit and / or the heaters are configured to bring the fuel cell system (as a whole) into an operating state and / or heat it to a temperature that enables (stable and / or low-wear) operation. For this purpose, the heaters may be designed to bring the component(s) of the fuel cell system to a suitable temperature as quickly and / or with minimal wear as possible (e.g., at least 5 °C or more). R.414551 -. 5 -The provision, by the control unit, of a specific heating current to a heater of one or more heaters in the fuel cell system in a second calculation step, whereby the heating currents (especially for each [first, second, and / or third] calculation step) sum to a total heating current, can involve outputting and / or supplying the heater(s) with corresponding heating currents specific to the second calculation step (or time). For example, the heating currents can be predefined and / or output by the control unit. The control unit can measure and / or determine the heating current(s) in each case. In other words, it can be provided that the control unit supplies a specific heating current and / or total heating current to the heater(s) at each calculation step (in particular a first, second, and / or third heating current).It may be provided that the first heating current (or total heating current) is specific to the first calculation step and / or first point in time. It may be provided that the second heating current (or total heating current) is specific to the second calculation step and / or second point in time. It may be provided that the third heating current (or total heating current) is specific to the third calculation step and / or third point in time. The first and / or second calculation points in time may already be completed. Preferably, the third calculation step may be carried out directly and / or immediately after the second calculation step and may include, in particular, an expected and / or predicted total heating current and / or the respective heating currents of the heaters (see below).The prediction (calculation) by the control unit of the total heating current for a third calculation step following the second calculation step (in time and / or directly) depending on the total heating current of the second calculation step, and in particular the total heating current of a first calculation step, in particular one immediately preceding and / or earlier than the second calculation step, can thereby determine an expected total heating current and / or R.414551 -. 6 -The calculation includes the respective individual heating currents. In other words, it is possible to calculate the total heating current and / or individual heating currents expected to be present in the third calculation step and / or at the third time point. The operation of the fuel cell system by the control unit, depending on the total heating current of the third calculation step, can include operating, in particular controlling and / or regulating, the fuel cell system. The total heating current (determined by the forecasting) can be used as the basis for this operation. Preferably, the operation can be designed to prevent exceeding a (too) high total heating current and / or the respective (individual) heating currents (see below). In other words, the control unit can be designed to prevent the occurrence of safety-critical and / or (excessively) wear-inducing operating conditions.Within the scope of the invention, it can be advantageous for the forecasting to be performed (in addition) as a function of the total heating current of a first calculation step, wherein, in particular, the first, second, and third calculation steps have temporally successive discrete points in time, and the third calculation step is specifically for a future and / or forecasted point in time. The first calculation step can have an initial and / or start step. It can also be provided that the first, second, and / or third calculation steps have or represent (later) successive calculation steps. Accordingly, the method or the calculation steps can be performed iteratively or continuously, or follow one another. The second calculation step can have a (temporally) current and / or (just) updated calculation step.Accordingly, the second calculation step can be specific to a second point in time (present or just past). The first calculation step can have a (temporally) past, previous, and / or last calculation step (e.g., 10 ms before the second point in time). R.414551 -. 7 -Accordingly, the first calculation step can be specific to a (past) first point in time, which in particular precedes the second point in time. At the first calculation step, or at the first point in time specific to the first calculation step, a (first) total heating current and / or a respective (first) heating current (or heating currents) can be provided (or have been provided). The third calculation step can be a (temporally) future, subsequent, and / or predicted calculation step. Accordingly, the third calculation step can be specific to a (future and / or next) third point in time, which in particular lies after (follows) the second point in time. At the third calculation step, or at the third point in time specific to the third calculation step, a (third) total heating current and / or a respective (third) heating current (or heating currents) can be provided.In other words, the third calculation step can be specific for forecasting the total heating current and / or the individual heating currents in the future. The actual calculation or forecasting can take place before the third point in time (e.g., immediately after the second point in time). Within the scope of the invention, it is conceivable that the provision, forecasting, and operation could be carried out during a cold start of the fuel cell system, particularly at temperatures below freezing.Within the scope of the invention, it may be provided that the forecasting comprises extrapolation, in particular linear extrapolation, wherein the total heating current of the third calculation step ^^^^,^∓^ (see equation 1 below) is calculated by summing - the total heating current ^^^^,^ of the second calculation step and - the difference between the total heating current ^^^^,^ of the second calculation step, and in particular the total heating current ^^^^,^^^ of the first calculation step. Accordingly, the following can be calculated and / or the following can apply (equation 1): R.414551 -. 8 -^^^^,^^^ = ^^^^,^ + (^^^^,^ − ^^^^,^^^) Therefore, for, preferably successive, calculation steps, the (third) total heating current, which is specific to the third calculation step and / or time, can be determined (continuously). This allows for a preliminary or predictive determination of the total heating current that will be present (in the future and / or next) (if no intervention occurs during operation). It is conceivable that at least two, three, or more calculation steps and / or further calculation steps are performed. Therefore, a prediction can include at least one further and / or fourth calculation step, which is specific to a calculation step or time that lies (even) further in the future and / or is the next calculation step or time. In other words, the index ^ can be increased by 1, based on the already calculated data, especially from the third calculation step.This allows for particularly early operation and / or a response to a (potential) current surge. Furthermore, it is conceivable that the operation of the fuel cell system by the control unit, depending on the total heating current of the third calculation step, includes providing a limited total heating current, whereby the limited total heating current is lower than the total heating current determined by forecasting in the third calculation step. In the simplest case, the limited total heating current can also be reduced compared to the (forecasted) total heating current of the third calculation step. The limited total heating current can be set to a value that is lower than or identical to the current limit for the total heating current. This can increase safety and / or reduce wear.At the same time, it may be provided that strong heating, in particular through high total heating currents and / or individual R.414551 -. 9 -Heating currents are not prevented too early and / or too severely. This allows for the advantageous achievement of rapid heating (as quickly as possible). It is also conceivable that a limited total heating current is provided if the total heating current from the third calculation step exceeds, or would exceed (if actually provided), a predefined limit for the total heating current. Alternatively, it can be provided that a predefined and / or planned total current and / or corresponding individual heating currents are supplied, particularly if the limit for the total heating current is not exceeded. This enables relatively rapid heating.Within the scope of the invention, it is optionally possible that providing a limited total heating current includes an even distribution of the current limit for the total heating current into individually limited heating currents at the heaters, particularly at the third calculation step and / or at the third time point. Thus, in the simplest case, equally large (limited) heating currents can be provided to the respective heaters. This allows for a simple, robust, and / or safe limitation of the total heating current, which advantageously requires only minimal computing power. For example, a current limit of 10 A could be used. The total heating current can then be set to (a maximum of) 10 A. With 10 heaters, each heater could therefore be provided with a heating current of 1 A. This ensures safety at the future and / or third time point.Advantageously, no excessive and / or wear-causing currents are provided. Furthermore, the invention may provide that the provision of a limited total heating current allows for the distribution of the current limit value for the total heating current to the respective heater R.414551. 10 -This includes specific limited heating currents, which are particularly specific for the maximum current consumption of the respective heater at maximum power and constant operating voltage. Accordingly, it is possible to provide a specific heating current or heating current limit. Thus, different limit values ​​for different heaters and / or components can be taken into account. This increases safety. It also further reduces the total heating time. With regard to the present invention, it is conceivable that the distribution involves weighting a linear deviation between a target temperature (of the i-th component) and an actual temperature (of the i-th component) of the respective heater, in particular a component of the fuel cell system specific to the heater.The fuel cell system can have a number ^ of heaters and / or components. Therefore, the following can be calculated and / or apply (Equation 2):. Here, ^^ can each have a weighting factor specific to the i-th heater and / or the i-th component. The weighting factor can be (comparatively) large if the actual temperature is (still) far from the target temperature. Conversely, the weighting factor can be (comparatively) small if the actual temperature is (already) close to the target temperature. Therefore, particularly within the framework of Equation 2, the following can be calculated and / or apply (Equation 3): ^^,^,^,^^^^ = ^^ ∗ ^^^^,^^^ Here, ^^,^,^,^^^^ can represent the specific limited heating current of the respective heater, which preferably corresponds to the weighting factor R.414551 - 11 -The weighting is applied. This advantageously enables particularly fast and / or efficient heating. The desired (operating) temperature of the fuel cell system can be reached (particularly) quickly, since components that were previously heated less intensely are heated more intensely and thus preferably do not delay reaching the operating temperature. Furthermore, it is conceivable that the distribution involves weighting based on a quadratic deviation between a target temperature ^^^^^,^ and an actual temperature ^^^^,^ of the respective heater, especially a component of the fuel cell system specific to that heater. The fuel cell system can have a number ^ of heaters and / or components. Accordingly, the following can be calculated and / or apply (Equation 4): Here, ^^ can have a weighting factor specific to the i-th heater and / or the i-th component. The weighting factor can be (comparatively) large if the actual temperature is (still) far from the target temperature. Conversely, the weighting factor can be (comparatively) small if the actual temperature is (already) close to the target temperature. Therefore, squaring the factor can significantly influence the weighting factor when there are large differences between the target and actual temperatures. The actual temperature can be measured, for example, by one or more temperature sensors, which are located on and / or in the heater and / or the component and / or the fuel cell system. Therefore, particularly within the framework of Equation 4, the following can be calculated and / or apply (Equation 5): ^^,^,^,^^^^ = ^^ ∗ ^^^^,^^^ R.414551 - 12 -Here, ^^,^,^,^^^^ can represent the specific limited heating current of the respective heater, which is preferably weighted according to the weighting factor. This advantageously enables particularly fast and / or efficient heating, especially compared to linear weighting. The desired (operating) temperature of the fuel cell system can be reached (particularly) quickly, since components that were previously heated less intensely are heated more intensely and thus preferably do not delay reaching the operating temperature. It can also be provided that, alternatively or additionally to the total heating current or the individual heating currents, the respective power is determined and / or predicted. If the heaters are controlled via the power, the power consumption of the heaters for the next calculation step can also be determined using an (empirical and / or simulated) model (e.g.,a PT1 filter) of the controlled power can be predicted. The power can be limited accordingly via a power limit (for the total power and / or individual power limits). For example, the limited power of a heater ^^^^,^ can be determined as a function of a power limit for the total power ^^^^ via the weighting factor (see above) and / or be calculable via: ^^^^,^ = ^^ ∗ ^^^^ The above problem is solved according to a second aspect by a fuel cell system according to the invention comprising: - a control unit (in particular according to the fourth aspect) which is configured to implement the method according to the first aspect, and - at least one or a number of heaters of the fuel cell system which are in particular configured to each heat at least one component (see above) of the fuel cell system.This results in the same advantages with regard to a fuel cell system according to the invention as already seen with regard to an R.414551 -. 13 -The above problem is solved according to a third aspect by a computer program product according to the invention, comprising instructions that, when executed by a computer, cause it to implement the method according to the first aspect. This results in the same advantages with respect to a computer program product according to the invention as have already been described with respect to a method according to the first aspect and / or a fuel cell system according to the invention according to the second aspect. The above problem is further solved according to a fourth aspect by a computer-readable data carrier according to the invention, in which instructions are stored that, when executed by a computer, cause it to carry out the method according to the first aspect.This results in the same advantages with regard to a computer-readable data carrier according to the invention as have already been described with regard to a method according to the first aspect and / or a fuel cell system according to the second aspect and / or a computer program product according to the third aspect. The above problem is further solved according to a fifth aspect by a control unit according to the invention, comprising a computing unit and a storage unit in which instructions are stored which, when at least partially executed by the computing unit, carry out a method according to the first aspect. It can be provided that the control unit, in particular the computing unit, carries out and / or initiates the method steps, for example by controlling the fuel cell system and / or R.414551. 14 -its (above) components and / or sensors. The control unit can send control signals to corresponding actuators of the fuel cell system to adjust them. The control unit can also receive sensor signals from sensors of the fuel cell system, such as temperature sensors, which are taken into account in the process, particularly during control and / or regulation. Based on this, for example, a current temperature can be determined. The control unit can have or provide a (respective) current output and / or connection for one and / or each heater (e.g., via a respective [physical] heating cable) to supply it with a respective (specific) heating current. The control unit can be designed as the central and / or sole control unit of the fuel cell system.Alternatively or additionally, a pilot control unit and / or inter-control unit may be provided, each of which offers one connection per heater to supply a heating current to it. The pilot control unit and / or inter-control unit may be connected to the (central) control unit via a bus. This results in the same advantages for a control unit according to the invention as have already been described for a method according to the first aspect and / or a fuel cell system according to the second aspect and / or a computer program product according to the third aspect and / or a computer-readable data carrier according to the fourth aspect.The above problem is further solved according to a sixth aspect by a system according to the invention, comprising a fuel cell system according to the second aspect and / or a control unit according to the fifth aspect. A system can comprise a (residential) building, industrial building, power plant, storage plant, vehicle, shipbuilding structure, aircraft or other system with, in particular, increased energy requirements. R.414551 -. 15 -It may be particularly advantageous to provide for a (essentially) stationary (immobile) application of the fuel cell system. This results in the same advantages for a system according to the invention as have already been described for a method according to the first aspect and / or a fuel cell system according to the second aspect and / or a computer program product according to the third aspect and / or a computer-readable data carrier according to the fourth aspect and / or a control unit according to the fifth aspect. Further advantages, features, and details of the invention will become apparent from the following description, in which several embodiments of the invention are described in detail with reference to the drawings.The features mentioned in the claims and the description can each be essential to the invention individually or in any combination. Figure 1 schematically shows a method for operating a fuel cell system, and Figure 2 shows a fuel cell system. The same reference numerals are used in the figures for the same technical features, even for different embodiments.Figure 1 shows a method for operating a fuel cell system 100, in particular a vehicle 200, by a control unit FCCU, comprising: - Providing 110, by the control unit FCCU, a respective heating current ^^,^ to a heater of a number n of heaters of the fuel cell system 100 in a second calculation step k, wherein the heating currents ^^,^ in sum result in a total heating current ^^^^,^, - Predicting 120, by the control unit FCCU, the total heating current ^^^^,^^^ for a third calculation step k+1 following the second calculation step k as a function of the R.414551 -. 16 -Total heating current of the second calculation step k and the total heating current of a first calculation step k-1, and operation 130 by the control unit FCCU of the fuel cell system 100 as a function of the total heating current of the third calculation step k+1. Within the scope of the invention, it can be advantageous that the first calculation step k-1, the second calculation step k, and the third calculation step k+1 have temporally successive discrete points in time, wherein, in particular, the third calculation step k+1 is specific for a future and / or predicted point in time. Within the scope of the invention, it is conceivable that the provision 110, the prediction 120, and the operation 130 are carried out during a cold start of the fuel cell system 100, in particular at temperatures below freezing.Within the scope of the invention, it may be provided that the forecasting 120 comprises an extrapolation 121, in particular linear extrapolation, wherein the total heating current ^^^^,^^^ of the third calculation step k+1 is calculated by summing - the total heating current ^^^^,^ of the second calculation step k and - the difference between the total heating current ^^^^,^ of the second calculation step k and the total heating current ^^^^,^^^ of the first calculation step k-1. It is further conceivable that the operation 130, by the control unit FCCU, of the fuel cell system 100, depending on the total heating current ^^^^,^^^ of the third calculation step k+1, comprises providing 131 a limited total heating current ^^^^,^^^,^, wherein in particular the limited total heating current ^^^^,^^^,^ is less than the total heating current ^^^^,^^^ determined by the forecasting 120. third calculation step k+1.It is also conceivable that the provision of 131 of a limited total heating current ^^^^,^^^,^ is carried out when the R.414551 -. 17 -The total heating current of the third calculation step k+1 exceeds a current limit value, in particular a predefined one. Within the scope of the invention, it is optionally possible that the provision of a limited total heating current comprises an even distribution of the current limit value for the total heating current into limited heating currents at the heaters. Furthermore, within the scope of the invention, it can be provided that the provision of a limited total heating current comprises a distribution of the current limit value for the total heating current into limited heating currents specific to each heater, which are in particular specific to a maximum current consumption of the respective heater at maximum power and constant operating voltage.With regard to the present invention, it is conceivable that the division 133 comprises a weighting 134 over a linear deviation between a setpoint temperature ^^^^^,^ and an actual temperature ^^^^,^ of the respective heater, in particular a component of the fuel cell system 100 specific to the heater. Furthermore, it is conceivable that the division 133 comprises a weighting 135 over a quadratic deviation between a setpoint temperature ^^^^^,^ and an actual temperature ^^^^,^ of the respective heater, in particular a component of the fuel cell system 100 specific to the heater. Fig. 2 shows a system 200, for example a vehicle 200, comprising a fuel cell system 100, comprising: - a control unit FCCU, which is configured to carry out the method according to the first aspect and / or Fig.1 to implement, and a number n of heaters of the fuel cell system 100, which are specifically configured to each heat (at least) one component of the fuel cell system 100. R.414551 -. 18 - The FCCU control unit can comprise a processing unit CU and a storage unit MU, in which instructions are stored which, when at least partially executed by the processing unit CU, carry out the procedure according to the first aspect and / or according to Fig. 1. The FCCU control unit can be integrated into the fuel cell system 100.

Claims

R.414551 - 19 -Claims 1. A method for operating a fuel cell system (100), in particular a fuel cell system (100) of a vehicle (200), by a control unit (FCCU) comprising: - providing (110), by the control unit (FCCU), a respective heating current (^^,^) to a heater of a number (n) of heaters of the fuel cell system (100) in a second calculation step (k), wherein the heating currents (^^,^) sum to a total heating current (^^^^,^), - forecasting (120), by the control unit (FCCU), the total heating current (^^^^,^^^) for a third calculation step (k+1) following the second calculation step (k) as a function of the total heating current (^^^^,^) of the second calculation step (k), and - operating (130), by the control unit (FCCU), the fuel cell system (100) as a function of the total heating current (^^^^,^^^) of the third calculation step (k+1).2.Method according to claim 1, characterized in that the forecasting (120) is carried out depending on the total heating current (^^^^,^^^) of a first calculation step (k-1), wherein in particular the first calculation step (k-1), the second calculation step (k) and the third calculation step (k+1) have successive discrete points in time, wherein in particular the third calculation step (k+1) is specific for a future and / or forecasted point in time. R.414551 - 20 -3. A method according to claim 1 or 2, characterized in that the provisioning (110), forecasting (120), and operation (130) are carried out during a cold start of the fuel cell system (100), particularly at temperatures below freezing.

4. A method according to any of the preceding claims, characterized in that the forecasting (120) comprises extrapolation (121), in particular linear extrapolation, wherein the total heating current (^^^^,^^^) of the third calculation step (k+1) is calculated by summing - the total heating current (^^^^,^) of the second calculation step (k) and - the difference between the total heating current (^^^^,^) of the second calculation step (k), and in particular the total heating current (^^^^,^^^) of the first calculation step (k-1). 5.A method according to one of the preceding claims, characterized in that the operation (130) of the fuel cell system (100) by the control unit (FCCU) comprises providing (131) a limited total heating current (^^^^,^^^,^) depending on the total heating current (^^^^,^^^,^) of the third calculation step (k+1), wherein in particular the limited total heating current (^^^^,^^^,^) is less than the total heating current (^^^^,^^^) of the third calculation step (k+1) determined by forecasting (120).

6. A method according to the preceding claim 5, characterized in that the provision (131) of a limited total heating current (^^^^,^^,^) is carried out when the total heating current (^^^^,^^) of the third calculation step (k+1) exceeds a current limit value (^^^^,^^^) for the total heating current, in particular a predefined one. R.414551 - 21 -7. A method according to claim 5 or 6, characterized in that providing (131) a limited total heating current (^^^^,^^^,^) comprises a uniform distribution (132) of the current limit value (^^^^,^^^) for the total heating current into limited heating currents (^^,^,^) at the heaters.

8. A method according to claim 5 or 6, characterized in that providing (131) a limited total heating current (^^^^,^^^,^) comprises a distribution (133) of the current limit value (^^^^,^^^) for the total heating current into limited heating currents (^^,^,^,^^^^) specific to the respective heater, which are in particular specific for a maximum current consumption of the respective heater at maximum power and constant operating voltage. 9.Method according to claim 8, characterized in that the division (133) comprises a weighting (134) over a linear deviation between a setpoint temperature (^^^^^,^) and an actual temperature (^^^^,^) of the respective heater, in particular a component of the fuel cell system (100) specific to the heater.

10. Method according to claim 8, characterized in that the division (133) comprises a weighting (135) over a quadratic deviation between a setpoint temperature (^^^^^,^) and an actual temperature (^^^^,^) of the respective heater, in particular a component of the fuel cell system (100) specific to the heater. R.414551 - 22 -11. Fuel cell system (100) comprising: - a control unit (FCCU) configured to implement the method according to any one of the preceding claims, and - a number (n) of heaters of the fuel cell system (100), which are specifically configured to each heat at least one component of the fuel cell system (100).

12. Computer program product comprising instructions which, when executed by a computer, cause the computer to implement the method according to any one of the preceding claims 1 to 10.

13. Computer-readable data carrier in which instructions are stored which, when executed by a computer, cause the computer to carry out the method according to any one of the preceding claims 1 to 10. 14.Control unit (FCCU) comprising a processing unit (CU) and a storage unit (MU) in which instructions are stored which, when at least partially executed by the processing unit (CU), perform a method according to any one of the preceding claims 1 to 10.

15. System (200), in particular vehicle (200), comprising a fuel cell system (100) according to claim 11 and / or a control unit (FCCU) according to claim 14.

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