Method for operating fuel cell system of motor vehicle, in particular of commercial vehicle, and motor vehicle

Abstract

The invention relates to a method for operating a fuel cell system (10) of a motor vehicle (12), comprising at least one hydrogen tank (14), at least one fuel cell (18) which can be supplied with hydrogen from the hydrogen tank (14), and a cooling device (30) for cooling at least part of the fuel cell system (10), according to the invention, the energy consumption of the cooling device (30) is predicted as a function of a planned travel route of the motor vehicle (12), a future temporal pressure curve of the pressure present in the hydrogen tank (14) is predicted, and a future temporal energy curve of the heating energy is predicted, on the basis of which energy curves, the energy consumption of the cooling device (30) is determined. The heating energy is supplied by a cooling device (30) to the hydrogen tank (14) as a function of the predicted energy consumption in order to achieve a pressure curve.

Description

Technical Field

[0001] The invention relates to a method for operating a motor vehicle fuel cell system, in particular a commercial vehicle fuel cell system. The invention also relates to a motor vehicle, in particular a commercial vehicle. Background Art

[0002] A method for predictive operation of a motor vehicle having a fuel cell system is known from WO 2016 / 083365 A1. Summary of the invention

[0003] The object of the present invention is to provide a method for operating a fuel cell system of a motor vehicle and a motor vehicle, in which a very efficient operation is possible.

[0004] This object is achieved by a method having the features of claim 1 and a motor vehicle having the features of claim 6. Advantageous embodiments with suitable developments of the invention are described in the dependent claims.

[0005] A first aspect of the invention relates to a method for operating a fuel cell system for a motor vehicle, the motor vehicle being preferably designed as a commercial vehicle, in particular a truck, and also referred to simply as a vehicle. The fuel cell system has at least one hydrogen tank, also referred to simply as a tank. Hydrogen (H 2 ). The fuel cell system (also referred to as a fuel cell device or a fuel cell arrangement) further comprises at least one fuel cell, which can be supplied with hydrogen from a hydrogen tank. It is well known that with the aid of a fuel cell, the chemical reaction energy of the hydrogen and the oxidant supplied to the fuel cell can be converted into electrical energy, which can be provided by the fuel cell. As an oxidant, oxygen is used in particular, such as the oxygen contained in the air, which is also supplied to or can be supplied to the fuel cell. The electrical energy provided or available by the fuel cell can, for example, be at least temporarily stored in an accumulator that is in particular designed as a battery, in particular a secondary battery. It is also conceivable that at least one motor is supplied or can be supplied with the electrical energy provided or available by the fuel cell, in particular directly and therefore bypassing the accumulator, wherein, alternatively or additionally, it is conceivable that the motor can be supplied with the electrical energy stored in the accumulator. By supplying the motor with electrical energy, the motor can be operated in a motor manner and thus works as an electric motor, whereby the motor vehicle can be driven in particular purely electrically.

[0006] Furthermore, the fuel cell system has a cooling device, by means of which at least a part of the fuel cell system can be cooled. In particular, a coolant, for example in liquid form, can flow through at least a partial region of the cooling device, by means of which at least a part of the fuel cell system can be cooled. The cooling device is also referred to as a cooling system.

[0007] In order to now achieve a particularly efficient, especially energy-efficient operation of the fuel cell system and the motor vehicle, the method according to the invention provides that, in particular with the aid of an electronic computing device, in particular of the motor vehicle, the energy consumption of the cooling device is predicted (i.e. estimated) and thus determined predictively / prospectively according to the planned driving route of the motor vehicle. This means in particular that the energy consumption is determined, in particular calculated, at a first moment or in a first time period, wherein the first moment or the first time period is before the second time period in time, during which the motor vehicle travels or drives through the planned driving route, i.e. actually travels along the driving route. In other words, the energy consumption is determined before the motor vehicle travels along the driving route or when the motor vehicle has not (yet) traveled along the driving route. The driving route may include at least one or more hydrogenation processes, also referred to as hydrogenation. In particular, because the driving route is a planned driving route, the hydrogenation process is therefore a planned hydrogenation process that may occur in the future, in which hydrogen is filled into the tank, in particular from outside the tank, so that the tank is at least partially filled with hydrogen. For example, the hydrogenation process is necessary, or is considered or determined to be necessary, to ensure that, for example, the motor vehicle can complete, in particular, the entire driving route. It is also conceivable that the planned driving route includes at least one or more parking times. In particular, since the driving route is a planned driving route, the stopping time is therefore a planned stopping time, during which the motor vehicle is, for example, particularly continuously at rest and / or the driving of the motor vehicle by the fuel cell system is particularly interrupted and / or the operation of the fuel cell system is particularly continuously inhibited. In particular, the discharge of hydrogen from the hydrogen tank and / or the provision of electrical energy by the fuel cell can be inhibited during the stopping time. In particular, the predicted energy consumption is a time-dependent energy consumption, and thus a time-dependent energy consumption curve of the energy consumption of the cooling device, wherein the energy consumption or energy consumption curve is a determined, calculated or estimated and thus predicted energy consumption curve, which characterizes the energy or energy amount that may be consumed by the cooling system when or while the motor vehicle is traveling (i.e. being driven) along the driving route.

[0008] In the method, a future time-dependent pressure profile of a pressure present in the hydrogen tank and which is or can be caused by the hydrogen stored or can be stored in the hydrogen tank is predicted, i.e. determined in advance or estimated, in particular as a function of the driving route. The future time-dependent pressure profile is thus, for example, a planned, in particular predefined or predefined, time-dependent pressure profile, wherein, for example, the pressure profile is a target profile that is to be set, i.e. to be achieved.

[0009] In the method of the present invention, a future, time-dependent energy curve of the heating energy is also predicted, according to which the heating energy is to be, i.e. should be, supplied from the cooling device to the hydrogen tank according to the predicted energy consumption in order to achieve the pressure curve. In other words, the energy curve is a time curve according to which, in particular during the process of a motor vehicle passing through or entering a driving route, the heating energy can or should be provided by the cooling device and supplied or can be supplied to the hydrogen tank, in order to thereby achieve the pressure curve, taking into account the predicted energy consumption of the cooling device. As a result, the cooling device can provide thermal energy in at least one or more sections of the driving route, which is supplied to the hydrogen tank, thereby using the hydrogen tank as a thermal buffer or heat sink. As a result, an excessively high thermal load, i.e. an excessively high cooling device temperature, can be avoided without having to actively cool the cooling device, for example by means of, in particular, an electric fan. Therefore, the method is a predictive thermal regulation or thermal management method for a fuel cell system. The invention is based in particular on the following recognition and consideration: Usually, in motor vehicles equipped with fuel cells (therefore also referred to as fuel cell vehicles), powerful cooling systems are used, which can especially remove fuel cell power losses from the fuel cell in the high load phase of the fuel cell and can ensure that the fuel cell complies with a relatively narrow temperature operating window, that is, the fuel cell or the fuel cell temperature remains within the temperature operating window. Therefore, the cooling device is used in particular to cool the fuel cell and thus keep it within the temperature operating window. For example, the temperature operating window is at least substantially ±8 to 10° C. In addition, in the case of fuel cell vehicles designed as heavy commercial vehicles, for example, the cooling system may also need to withstand additional heat input from activated retarder brakes (for example, designed as retarder / retarder, brake resistor, etc.), especially because the cooling system is also used, for example, to cool the vehicle retarder brake, which is designed as a retarder or brake resistor. Usually, the cooling system (cooling device) therefore cools the retarder brake and the vehicle fuel cell at least for a period of time. In the high load phase of the fuel cell, long-term startup can therefore occur, that is, long periods of time when, for example, an electric fan with a power of up to 30 kW or 40 kW is required or required or has a power of up to 30 kW or 40 kW. The aforementioned coolant is cooled by means of a fan (which can be a component of a cooling device or a cooling system), for example, in particular by means of a heat exchanger, in particular in such a way that air flowing around the heat exchanger is conveyed by means of the fan when the fan is activated, the heat exchanger being designed, for example, as an air-coolant heat exchanger. The heat is transferred from the coolant to the air flowing around the heat exchanger and conveyed by means of the fan via the heat exchanger. In addition, for example, a particularly long heat flow may be required for heating cryogenic liquid hydrogen, which in a correspondingly designed cooling system (cooling device) can be diverted from the heat supply of the heat source. For example, fuel cells and retarding brakes can be used as heat sources, the heat of which is also referred to as waste heat, which can be used to heat hydrogen in a tank, for example, which is contained or can be contained in a hydrogen tank and / or to heat hydrogen discharged from the hydrogen tank and on the way to the fuel cell.In particular, the hydrogen contained or capable of being contained in the hydrogen tank or the hydrogen tank can therefore be used as a heat sink in order to relieve the load on the cooling system (cooling device) and thereby save energy, for example, in high-load phases with high energy consumption of the cooling device, for example caused by the operation of the aforementioned fan, by buffering heat, in particular waste heat, in the hydrogen tank. In other words, the method of the invention allows heat, in particular waste heat, to be discharged from the cooling device (in particular from the coolant) in a particularly effective and efficient manner, but without or not exclusively by the operation of the aforementioned fan, but in particular in such a way that heating energy is discharged from the cooling device (in particular from the coolant) according to the energy curve and supplied to the hydrogen tank, in particular to the hydrogen contained in the hydrogen tank.

[0010] The heating energy is therefore or characterizes the heating energy or heat discharged from the cooling device (especially from the coolant), thereby avoiding the excessive temperature of the cooling device without running the fan. In order to discharge the heating energy (heat) from the cooling device, the heating energy is supplied to the hydrogen tank, which is therefore at least temporarily used as a thermal buffer or heat sink. If - especially more - heat is fed into the hydrogen tank, that is, especially more, heat is supplied to the hydrogen tank, the pressure in the hydrogen tank increases due to more hydrogen gasification inside the hydrogen tank (tank). The pressure in the hydrogen tank should not increase beyond a particularly pre-set or preset limit, especially the load limit of the tank, and the pressure in the hydrogen tank, also referred to as the tank pressure, should be reduced before the hydrogenation process, also referred to as the tank filling process, and / or before the particularly long motor vehicle stationary phase or parking time. The method of the present invention can now ensure energy saving by, on the one hand, adjusting in a targeted manner, especially increasing the tank pressure and on the other hand, especially matching the pressure conditions before the hydrogenation process and / or parking time, so that a particularly advantageous and particularly efficient fuel cell system and motor vehicle operation can be achieved as a whole. The pressure curve and the energy curve are also referred to as trajectories, in particular in the following manner, namely, the pressure curve is also referred to as the pressure trajectory and the energy curve is also referred to as the heating energy trajectory. The heating energy is, for example, a target heating energy here, which is to be supplied, i.e. should be supplied to the hydrogen tank, so as to achieve, i.e. reach, the pressure trajectory. Therefore, in the method, the pressure trajectory and the heating energy trajectory associated therewith are determined predictively. In addition, the energy consumption of the cooling device is determined predictively, in particular calculated, to determine at least one or more time intervals (i.e. stages), in which at least one or more time intervals, in particular the energy of the cooling device can or should be discharged to the hydrogen tank. "Energy discharge" means that, in particular during the respective stages, the heating energy and therefore the heat is provided by the cooling device and is supplied or can be supplied to the hydrogen tank, so as to thereby appear, i.e. reach, the predicted pressure curve. Therefore, by means of the present invention, compared with conventional solutions, the energy consumption of the fuel cell system can be reduced, in particular with respect to thermal management, so that the energy consumption of the entire motor vehicle can be reduced compared with conventional solutions. As a result, the motor vehicle can be operated particularly advantageously in terms of energy and cost. In addition, overloading of the cooling device and the resulting performance limitation of components (e.g. motor vehicle drive) can be at least postponed or avoided.

[0011] In order to achieve particularly efficient operation of the fuel cell system and the entire motor vehicle as a whole, it is provided in an advantageous design of the present invention that the pressure curve and the energy curve (i.e., the trajectory) can be predicted in such a way that, in the first operating phase of the cooling device (the predicted energy consumption of the first operating phase is greater than the second operating phase of the cooling device), more thermal energy is supplied from the cooling device to the hydrogen tank than in the second operating phase. As a result, the hydrogen tank can be effectively and efficiently used as a thermal buffer at least temporarily, thereby avoiding excessive temperatures of the cooling device without actively cooling the cooling device, for example, by a so-called fan. This means in particular that, for example, the time integral of the energy curve in the respective first operating phase is greater than the second integral of the energy curve in the respective second operating phase. In other words, the first part of the heating energy is greater than the second part of the heating energy, wherein the first part is supplied to the hydrogen tank from the cooling device in the respective first operating phase and the second part in the respective second operating phase. In particular, the first part is greater than zero, wherein the second part can be greater than zero or equal to zero.

[0012] It has proven to be particularly advantageous that no heat energy is transferred from the cooling device to the hydrogen tank in at least one of the second operating phases, thereby effectively and efficiently avoiding, on the one hand, excessive temperatures in the cooling device and, on the other hand, excessive pressure increases in the hydrogen tank.

[0013] A further embodiment is characterized in that the pressure curve is predicted in such a way that the pressure over its entire pressure curve is always (i.e. continuously) less than or equal to a particularly predefined or predefinable maximum pressure. As a result, thermal energy can be effectively and efficiently transferred from the cooling device to the hydrogen tank, while at the same time overloading or damaging the hydrogen tank can be reliably avoided.

[0014] In order to be able to use the hydrogen tank as a thermal buffer particularly effectively and efficiently, it is provided in a further embodiment of the invention that at least the pressure curve is predicted based on at least one filling process provided for filling the hydrogen tank and / or based on at least one stopping time of the vehicle, during which the vehicle is stationary and not driven, in particular not driven, by means of the fuel cell system. In particular, the filling process and / or the stopping time belong to the planned driving route.

[0015] A second aspect of the invention relates to a motor vehicle, which is preferably designed as a commercial vehicle, in particular a truck, which is also referred to as vehicle for short and is designed to carry out the method according to the first aspect of the invention.

[0016] For example, the pressure trajectory and the heating energy trajectory (i.e., the pressure curve and the energy curve) are determined (i.e., predicted) as follows: in the high-load stage when the energy consumption of the cooling device is higher, more heat is discharged from the cooling device to the hydrogen tank, that is, heat is supplied to the hydrogen tank. At this time, the maximum pressure (the maximum pressure is or represents the maximum pressure limit) is preferably observed, that is, the tank pressure is always less than or equal to the maximum pressure.

[0017] For example, the pressure trajectory and the heating energy trajectory are determined, in particular predicted, in such a way that, in particular in partial load phases and / or low load phases of the cooling device (for example, in the respective partial load phases and / or low load phases, the energy consumption of the cooling device is lower than in the corresponding high load phases), in particular compared to the respective high load phases, the heat supply from the cooling device to the hydrogen tank is reduced (i.e. suppressed) or completely stopped (i.e. prevented), i.e. heating energy is supplied from the cooling device to or into the hydrogen tank, so that a decompression in the hydrogen tank is achieved, in particular compared to the respective high load phases, i.e. the pressure in the hydrogen tank is reduced, which is achieved in particular by the hydrogen consumption that occurs during the partial load phases and / or low load phases, during which hydrogen is discharged from the hydrogen tank and, for example, supplied to the fuel cell. In this case, for example, by planning (i.e. predictive determination), in particular calculation, the hydrogen consumption along the driving route and the pressure curve (also called pressure change) of the pressure in the hydrogen tank are also known, so that it can be implemented in a predictive manner. In other words, the planned driving route includes, for example, the predicted consumption of hydrogen in the hydrogen tank, in particular caused by the fuel cell system, and / or at least another other consumption.

[0018] If, for example, no filling process is planned or known, a filling process can be scheduled when the amount of hydrogen in the hydrogen tank, also referred to as the liquid level, falls below, in particular, a preset or pre-settable threshold value, and the aforementioned function for buffering the waste heat of the cooling device in the hydrogen tank can be limited (i.e. suppressed) or reduced, or completely prohibited (i.e. deactivated). BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Further advantages, features and details of the invention are obtained from the following description of preferred embodiments and in conjunction with the accompanying drawings. The features and feature combinations mentioned above in the specification and the features and feature combinations mentioned below in the description of the drawings and / or shown individually in the drawings can be used not only in the respectively specified combination, but also in other combinations or alone without exceeding the scope of the invention. The drawings show:

[0020] Figure 1 is a schematic diagram of a fuel cell system of a motor vehicle, which is preferably designed as a commercial vehicle, in particular a truck;

[0021] Figure 2 It is a method for running Figure 2 A flow chart of a method for a fuel cell system of a motor vehicle is schematically shown;

[0022] Figure 3 It is a schematic cross-sectional view of a portion of a tank system including a hydrogen tank of a fuel cell system.

[0023] In the figures, identical or functionally identical components are provided with the same reference symbols. DETAILED DESCRIPTION

[0024] Figure 1 Shown in schematic diagram Figure 2 The schematic diagram of the fuel cell system 10 of a motor vehicle 12 is shown in FIG. 1 , which is designed as a commercial vehicle, in particular a truck. Figure 1-3 In the following, a method for operating a fuel cell system 10 is described, wherein the method allows a particularly efficient, in particular energy-efficient, operation of the fuel cell system 10 and of the entire motor vehicle 12 to be achieved.

[0025] Can be obtained from Figure 1 As can be seen in FIG. 1 , the fuel cell system 10 has at least one Figure 1 The hydrogen tank 14, which is also referred to as a tank for short, is shown very schematically in the figure and can contain or has been filled with hydrogen. Figure 3 As can be seen at a glance, the hydrogen tank 14 is part of a tank system 16, also referred to as a tank arrangement, which will be explained in more detail below. The hydrogen is stored under high pressure in the hydrogen tank 14, so that a pressure, also referred to as tank pressure, exists in the hydrogen tank 14, which is caused by the hydrogen stored in the hydrogen tank 14 and is, for example, and should in particular be, in the range of 6 bar to 15 bar (inclusive). In particular, the hydrogen tank 14 contains both a liquid phase and a gaseous phase of hydrogen. In addition, the fuel cell system 10 comprises at least one fuel cell 18, such as Figure 1 As shown by the middle arrow 20, the fuel cell can be supplied with hydrogen from the hydrogen tank 14. For this purpose, for example, hydrogen is discharged from the hydrogen tank 14 and supplied, in particular in a gaseous state, to the fuel cell 18. The fuel cell 18 can be, for example, a fuel cell stack, or the fuel cell 18 is a component of a fuel cell stack, which can have a plurality of fuel cells 18.

[0026] Arrows 22, 24 indicate waste heat (also referred to as heat for short) which is released or provided by the fuel cell 18, for example during its operation. Arrow 26 indicates waste heat (also referred to as heat for short) which can be released (i.e. provided) by at least one retarding brake 28 of the motor vehicle 12, in particular during the operation of the retarding brake 28. With the aid of a retarding brake, for example, which is designed as a retarder, the motor vehicle 12 can be braked, in particular in such a way that the speed of the motor vehicle 12 along the lane is not increased or is reduced. For example, the waste heat of the fuel cell 18 and the waste heat of the retarding brake 28 form a total waste heat. Arrow 22 indicates, for example, that a first part of the total waste heat is output to the fuel cell system 10 at Figure 1The cooling device 30, which is shown very schematically in the drawing and is also referred to as the cooling system, is particularly discharged in such a way that a first part of the total waste heat is transferred, for example, via a heat exchanger / heat transferor, to a coolant, which is particularly liquid, of the cooling device 30. Thus, the fuel cell 18 and preferably also the retarder 28 are also cooled by means of the cooling device 30. The second part of the total waste heat is particularly discharged by the fuel cell system 10 in the cooling device 30. Figure 1 The heating device 32, which is shown very schematically and is also referred to as a heater, can be connected to or transferred to the hydrogen tank 14 and the hydrogen contained in the hydrogen tank 14, so that the second part of the total waste heat is away from the cooling device 30 and therefore does not reach the cooling device 30 and is discharged by it. This can advantageously keep the cooling device 30 very low, especially the thermal load. The cooling device 30 has, for example, a refrigerant circulation circuit, through which a coolant can flow. For example, the cooling device 30 includes a fan, which can be driven in particular electrically, by which air can be conveyed. The air can, for example, flow around a radiator through which the coolant can flow. Since the heat is transferred from the coolant via the radiator to the air flowing around the radiator and conveyed by the fan, the coolant can be cooled. Because, as indicated by arrows 22 and 24, not all waste heat reaches the cooling device 30 and is discharged therefrom, but a second part of the total waste heat is directed to or transferred to the hydrogen tank 14 and is thus buffered, for example, by means of the hydrogen tank 14, it is possible, for example, to advantageously shorten the excessive operating time of the fan within the total duration, thereby enabling particularly efficient, in particular energy-efficient, operation of the cooling device 30 and the fuel cell system 10 as a whole.

[0027] By transferring heat (i.e., a second portion of the total waste heat) to the hydrogen tank 14, such as Figure 1 As shown by the middle arrow 34, the liquid hydrogen (i.e., at least a portion of the hydrogen in the hydrogen tank 14 in the liquid phase) contained in the hydrogen tank 14 is caused to gasify, so that the tank pressure increases. As will be explained in detail below, the hydrogen tank 14, in particular the tank system 16, is used to reduce the load of the cooling device 30 by caching the waste heat (i.e., the second part of the total waste heat) in the hydrogen tank 14 when the cooling device 30 is in a high-load stage with high energy consumption, thereby saving energy, especially electrical energy. To this end, as will be explained in detail below, the energy consumption of the cooling device 30 is predicted based on the planned and, for example, predicted driving route of the motor vehicle 12. In addition, the future time-pressure curve of the pressure (i.e., the tank pressure) present in the hydrogen tank 14 is predicted. For example, the energy consumption and pressure curve (also referred to as the pressure trajectory) are predicted, i.e., determined predictively, by means of an electronic computing device, in particular, of the motor vehicle 12. In addition, in particular with the aid of an electronic computing device, a future, temporal energy curve, also referred to as an energy trajectory or heating energy trajectory, of the heating energy is predicted, according to which the heating energy is to be supplied, i.e. should be supplied or will be supplied to the hydrogen tank 14 by the cooling device 30 and thus, for example, via the cooling device 30 in accordance with the predicted energy consumption in order to achieve the pressure curve. The heating energy is therefore heat, i.e. thermal energy or heat energy, which is, for example, Figure 1 In other words, the arrow 24 represents, for example, heating energy, which is the second part of the total waste heat and is supplied or supplied to the hydrogen tank 14 by the cooling device 30, for example via a coolant or with the aid of a coolant, according to the predicted energy curve, in order to thereby realize the pressure curve, in particular during the actual driving of the motor vehicle 12 along the planned driving route, in particular.

[0028] exist Figure 2 In particular, a planning module, also referred to as logistics planning or designed to carry out logistics planning, is schematically shown in the figure, which is designated by 34. Thus, for example, a driving route, also referred to as a trip, is planned (i.e., planned in advance) by means of the planning module 34. For example, by means of the planning module 34, it is determined, in particular, it is stipulated, when, i.e., at which time or during which time period the motor vehicle 12 travels which driving route (also referred to as a journey), where, i.e., at which point on its driving route the hydrogen is refueled and thus the filling process is carried out, when, i.e., at which moment the driving of the motor vehicle 12 along the driving route is interrupted or where a stop time is planned and thus occurs. A filling process, also referred to as a hydrogen filling process, is a process by means of which or during which hydrogen is filled into the hydrogen tank 14, in particular from outside the hydrogen tank 14, in particular from outside the entire motor vehicle 12. The corresponding stop time is a time period or time interval during which the motor vehicle 12 is stationary and is therefore not driven by means of the fuel cell system 10, so that, for example, no hydrogen is discharged from the hydrogen tank 14, in particular to the fuel cell 18, during the corresponding stop period. When planning the driving route, for example, other parameters are taken into account, which characterize the driving route or the motor vehicles 12 along the driving route. These parameters may include, for example, the loading condition of the motor vehicle 12 and / or the planned operation of the motor vehicle 12 at each use, such as, for example, a cooling system for cooling the cargo space of the motor vehicle 12.

[0029] Arrow 36 indicates that relevant, in particular all relevant trip planning data characterizing the planned driving route are transmitted to and received by the operating strategy module 38. The operating strategy module 38 determines, in particular calculates, for example, an operating strategy, in particular an overall operating strategy, for the planned driving route (also referred to as a trip). For example, an operating strategy is a predictively determined, i.e. planned operating strategy, according to which the fuel cell system 10 is operated or will be operated, in particular when the motor vehicle 12 actually travels along the driving route. This includes, for example, a torque to be provided by the drive device for driving the motor vehicle 12 and thus for driving it along the driving route, also referred to as the driving distance, so that the motor vehicle 12 can complete the driving route, from which a target trajectory is derived regarding the power of the fuel cell 18, also referred to as the fuel cell power, and the charge profile of the buffer battery of the motor vehicle 12 associated therewith. The drive device includes, for example, at least one electric machine, by means of which the motor vehicle 12 can be driven, in particular purely electrically, so that the motor vehicle 12 thus travels along the driving route. The buffer battery is a battery, in particular a secondary battery, in which, for example, the electrical energy provided or available by the fuel cell 18 can be at least temporarily stored, i.e. buffered. For example, a drive device, in particular an electric motor, can be supplied with electrical energy provided by the fuel cell 18 and / or electrical energy stored in the battery, so that the motor vehicle 12 can be electrically driven by means of the electric motor. The operating strategy also takes into account, for example, at least one or more retarding brake systems of the motor vehicle 12, such as the retarding brake 28. In other words, the operating strategy also includes, for example, a strategy for operating the retarding brake 28 along the driving route, wherein the retarding brake 28, as described above, causes or can cause an additional heat input, in particular to the cooling device 30.

[0030] In addition, the pressure curve and the energy curve are predicted. The heating energy is the target heating energy that will be supplied to the hydrogen tank 14 to achieve, i.e. realize, the pressure curve, in particular during the driving of the motor vehicle 12 along the driving route. By predicting the energy consumption of the cooling device 30, operating phases, also referred to as phases for short, can be determined during which energy can be discharged into the hydrogen tank 14 while the motor vehicle 12 is driving along the driving route, so that heating energy can be supplied to the hydrogen tank 14. In particular, when driving times, journey times, habits regarding normal operating times and parking times are evaluated, parking times can perhaps also be estimated, i.e. predicted.

[0031] The determined, in particular calculated, operating strategy is transmitted in particular from operating strategy module 38 to thermal management module 42 and received by thermal management module 42, as indicated by arrow 40. Operating strategy module 38 and / or thermal management module 42 are, for example, components of the aforementioned electronic computing device.

[0032] The pressure trajectory and the heating energy trajectory are also referred to as trajectories for short and are target trajectories. Here, the thermal management module 42 is designed to realize (i.e., achieve) a target trajectory that is strategically determined in advance, especially calculated, so that the fuel cell system 10 is operated, especially controlled or regulated, so that the target trajectory is implemented, that is, the fuel cell system 10 is operated or operated according to the predicted target trajectory. This is done, for example, in the following way: the thermal management module 42 drives an actuator device 46, also called an actuator device or a thermal system actuator device, especially of the fuel cell system 10, as shown by arrow 44. The actuator device 46 includes, for example, a valve, a pump and at least one or more fans, such as the aforementioned fan. For example, a sensor device 48 is also provided, which is also called a thermal system sensor device. As shown by arrow 50, the sensor device 48 can detect a measured quantity, such as the pressure and / or temperature of the fuel cell system 10, and transmit it to the thermal management module 42, which can drive, i.e., operate, especially control or regulate the fuel cell system 10, especially the actuator device 46, based on the measured quantity measured by means of the sensor device 48, so as to achieve the target trajectory in particular, that is, to operate the fuel cell system 10 according to the target trajectory. The measured quantity is, for example, the aforementioned tank pressure. Another measured quantity is, for example, another pressure of the fuel cell system 10. In addition, the measured quantity may include at least one or more temperatures of the fuel cell system 10. The respective pressures are detected, for example, by means of corresponding pressure sensors. The respective temperatures are detected, for example, by means of corresponding temperature sensors. For example, the fuel cell system 10, in particular the actuator device 46, is adjusted to a preset or pre-settable target value by means of the thermal management module 42, in particular so adjusted that the target trajectory is actually achieved. If the target set value (for example, tank pressure and / or coolant temperature) calculated predictively is not reached or cannot be reached, the predictive operating strategy can be re-determined, in particular recalculated, in particular by the operating strategy module 38, as shown by the arrow 52, ​​in particular based on, for example, new state data measured by means of the sensor device 48 and thus determined by means of the thermal management module 42 and in particular transmitted to the operating strategy module 38 and received by it (as indicated by the arrow 52). This can be performed, for example, periodically, in particular based on the current state of the motor vehicle 12 and the measured values, respectively. For example, the coolant includes at least water, so the coolant is also called cooling water, for example.

[0033] For example, as shown by arrow 54, the thermal management module 42 can transmit at least one or more set values ​​to an operation module 56 for operating, especially adjusting or controlling the tank system 16, in order to heat the hydrogen tank 14, that is, to supply heating energy to the hydrogen tank 14 according to the energy curve and thereby heat it up, that is, to heat it. For example, the operation module 56 is a component of an electronic computing device. The operation module 56 is, for example, referred to as a tank control module or a tank adjustment module. For example, as shown by arrow 54, a demand for heat removal from the hydrogen tank 14 is transmitted from the thermal management module 42 to the operation module 56, especially at a desired time or during a desired time period, and is especially received by the operation module 56. The operation module 56 implements the set values ​​provided by the thermal management module 42 and received by the operation module 56, especially within a possible range and / or within an allowable pressure interval, which corresponds, for example, to the aforementioned range of 6 bar to 15 bar, and feeds back the implementation result to the thermal management module 42, as indicated by arrow 58. The feedback includes, for example, an estimated amount of heat removed from or by the hydrogen tank 14 based on a set value and, in particular, a tank pressure present in the hydrogen tank 14 and caused in particular by the hydrogen contained in the hydrogen tank 14 as an actual pressure. A central (i.e. active) control or regulating element for regulating (i.e. adjusting) the heat flow in the hydrogen tank 14, i.e. for regulating the heating energy supplied to the hydrogen tank 14, is, for example, Figure 2 The valve 60 shown in particular schematically and designed as a pressure valve, in particular a pressure control valve or a pressure regulating valve, can be driven, for example, by the operating module 56 and thus operated, in particular adjusted or controlled. By means of the valve 60, for example, the pressure Figure 3 The heat exchanger 62 is shown as a flow or flow of, in particular, gaseous hydrogen. The heat exchanger 62 is a component of the tank system 16, which will be explained in further detail below. If, for example, the valve 60 is fully open, a maximum flow of heat into the hydrogen tank 14 is permitted. If the valve 60 is closed, the hydrogen tank 14 is, for example, not (any more) heated, which can occur in particular in the case of partial load, so that, for example, the tank pressure is (again) reduced.

[0034] By means of the method, the energy consumption of the fuel cell system 10 can be reduced compared to conventional solutions, whereby the energy consumption of the entire motor vehicle 12 can be kept very low. As a result, the motor vehicle 12 can be operated particularly cost-effectively. In addition, overloading of the cooling device 30 and the resulting reduction in the performance of components (e.g., the drive) can be postponed or completely avoided.

[0035] The cooling device 30 has, for example, a cooling circuit 64 through which a coolant can flow. Figure 366, 68 thereof are partially shown in FIG. The pipe pieces 66, 68 can be flowed through by a coolant. With the help of the pipe piece 66, a coolant containing in particular heat (for example a second part of the total waste heat) can be supplied to the heat exchanger 62. For example, the coolant flow through the pipe piece 66 and in particular to the heat exchanger 62 can be regulated by a valve 70 arranged in the pipe piece 66. The valve 70 can be driven by the thermal management module 42, so that the thermal management module 42 can regulate, in particular control or adjust the coolant flow through the pipe piece 66 to the heat exchanger 62 via the valve 70. Through the pipe piece 68, the coolant can be discharged from the heat exchanger 62.

[0036] The hydrogen tank 14 can be vented via the vent line 72 and can be filled via the tank filling device 74. The discharge line is denoted by 76, a valve designed, for example, as a tank valve is denoted by 78, and a valve designed, for example, as a safety valve is denoted by 80. For example, hydrogen can be discharged from the hydrogen tank 14 via the line piece 82 and in particular supplied to the fuel cell 18. It can be seen that the operating module 56 can, for example, drive and thereby operate the valve 78 and the valve 60, and that the operating module 56 can, for example, drive and thereby operate the heat exchanger 62. The aforementioned temperature sensor is at Figure 3 84 is indicated in the figure, and the aforementioned pressure sensor is indicated in the figure 86. With the aid of the measuring device 88, the amount of hydrogen (still) contained in the hydrogen tank 14 can be detected, wherein the amount of hydrogen contained in the hydrogen tank 14 is also referred to as the liquid level. The measuring device 88 can provide at least one signal, in particular an electrical signal, which characterizes the liquid level, and the signal can be received by the operation module 56. The operation module 56 can feed back the detected temperature, pressure and liquid level to the operation strategy module 38, which can create a set value based on it and provide it to the operation module 56, so that, for example, the tank system 16 can be operated, in particular controlled or adjusted, in particular based on the detected temperature, pressure and liquid level, in particular in the following way, that is, so that the target trajectory is actually achieved (i.e., achieved).

[0037] from Figure 3 , it can be seen that the heat contained in the coolant (i.e. the aforementioned second part of the total waste heat) can be transferred to the hydrogen tank 14, in particular the hydrogen in the hydrogen tank 14, via the heat exchanger 62, so that the hydrogen tank 14 and the hydrogen contained in the hydrogen tank 14 are heated, i.e., the temperature is increased. As a result, the hydrogen tank 14 can be used at least temporarily as a heat buffer, thereby advantageously keeping the energy consumption of the cooling device 30 low. In addition, for example, the heat contained in the coolant (i.e. the second part of the total heat) can be transferred to the hydrogen, which flows through the pipe piece 82, in particular in a gaseous state, for example, by means of the pipe piece 82, and the hydrogen is discharged from the hydrogen tank 14 and supplied to the fuel cell 18. As a result, the hydrogen supplied to the fuel cell 18, in particular in a gaseous state, can be heated, in particular preheated, on its way to the fuel cell 18, so that the second part of the waste heat can be advantageously discharged, in particular without using the aforementioned fan.

[0038] Reference numerals list

[0039] 10 Fuel Cell System

[0040] 12 Motor Vehicles

[0041] 14 Hydrogen tank

[0042] 16 tank system

[0043] 18 Fuel Cell

[0044] 20 Arrow

[0045] 22 Arrow

[0046] 24 Arrow

[0047] 26 Arrow

[0048] 28 Retarder brake

[0049] 30 Cooling device

[0050] 32 Heating device

[0051] 34 Arrow

[0052] 35 Planning Module

[0053] 36 Arrow

[0054] 38 Run Strategy Module

[0055] 40 Arrow

[0056] 42 Thermal Management Module

[0057] 44 Arrow

[0058] 46 Actuator device

[0059] 48 Sensor Device

[0060] 50 Arrow

[0061] 52 Arrow

[0062] 54 Arrow

[0063] 56 Run Module

[0064] 58 Arrow

[0065] 60 valve

[0066] 62 Heat Exchanger

[0067] 64 Cooling circuit

[0068] 66 Pipe fittings

[0069] 68 Pipe fittings

[0070] 70 valve

[0071] 72 Exhaust pipe

[0072] 74 Tank filling device

[0073] 76 Discharge pipeline

[0074] 78 valve

[0075] 80 valve

[0076] 82 Pipe fittings

[0077] 84 Temperature Sensor

[0078] 86 Pressure Sensor

[0079] 88 Measurement device.

Claims

1. A method for operating a fuel cell system (10) of a motor vehicle (12), the fuel cell system (10) having at least one hydrogen tank (14), at least one fuel cell (18) which can be supplied with hydrogen from the hydrogen tank (14), and a cooling device (30) for cooling at least a part of the fuel cell system (10), wherein: - predicting the energy consumption of the cooling device (30) based on the planned driving route of the motor vehicle (12), - predicting a future, time-dependent pressure curve of the pressure prevailing in the hydrogen tank (14), - predicting a future, time-dependent energy profile of the heating energy to be supplied to the hydrogen tank (14) by the cooling device (30) in accordance with the predicted energy consumption in order to achieve the pressure profile.

2. The method according to claim 1, characterized in that: The pressure curve and the energy curve are predicted in such a way that, in a first operating phase of the cooling device (30), more thermal energy is supplied to the hydrogen tank (14) from the cooling device (30) than in a second operating phase, wherein the energy consumption in the first operating phase is greater than that in the second operating phase of the cooling device (30).

3. The method according to claim 2, characterized in that In at least one of the second operating phases, no thermal energy is transferred from the cooling device (30) to the hydrogen tank (14).

4. The method according to any one of the preceding claims, characterized in that The pressure curve is predicted in such a way that the pressure is always less than or equal to the maximum pressure over its entire pressure curve.

5. The method according to any one of the preceding claims, characterized in that At least the pressure curve is predicted as a function of at least one filling process provided for filling the hydrogen tank (14) and / or as a function of at least one parking time of the motor vehicle (12).

6. A motor vehicle (12) designed to carry out the method according to one of the preceding claims.

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