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

Abstract

The present invention relates to a method for operating a fuel cell system (10) of a motor vehicle (12), the fuel cell system (10) comprising at least one hydrogen tank (14), at least one fuel cell (18) capable of supplying hydrogen from the hydrogen tank (14), and a cooling device (30) for cooling at least a portion of the fuel cell system (10), in which the energy consumption of the cooling device (30) is predicted according to a planned driving route of the motor vehicle (12), a future time-pressure curve of the pressure that will prevail in the hydrogen tank (14) is predicted, and a future time-energy curve of the amount of thermal energy to be supplied from the cooling device (30) to the hydrogen tank (14) according to the predicted energy consumption in accordance with the energy curve in order to realize the pressure curve is predicted.

Description

[Technical Field]

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

[0002] A method for predictive operation of a motor vehicle equipped with a fuel cell system is described in US Pat. No. 5,629,999. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2016 / 083365(A1) Summary of the Invention [Problem to be solved by the invention]

[0004] 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 such a way that particularly efficient operation can be achieved. [Means for solving the problem]

[0005] This object is solved by a method with the features of patent claim 1 and a vehicle with the features of patent claim 6. Advantageous embodiments with suitable developments of the invention are set out in the further claims.

[0006] A first aspect of the present invention relates to a method for operating a fuel cell system in a motor vehicle, also referred to simply as a vehicle, preferably in the form of a commercial vehicle, in particular a large goods vehicle. The fuel cell system has at least one hydrogen tank, also referred to simply as a tank. Hydrogen (H2) can be or is received in the hydrogen tank. The fuel cell system, also referred to as a fuel cell device or fuel cell appliance, comprises at least one fuel cell capable of supplying hydrogen from the hydrogen tank. As is known, the energy of a chemical reaction between hydrogen and an oxidant supplied to the fuel cell is converted by the fuel cell into electrical energy, which is supplied by the fuel cell. In particular, oxygen contained in air, for example, is used as the oxidant and can also be supplied to the fuel cell. The electrical energy supplied or available to be supplied by the fuel cell can be at least temporarily stored in an electrical energy storage device, in particular designed as a battery, in particular as a secondary battery. Furthermore, it is conceivable to supply or provide electrical energy to at least one electric engine. The electric energy can be or is supplied by the fuel cell, in particular directly, bypassing the electric energy storage device, whereby, alternatively or additionally, the electric energy stored in the electric energy storage device can be supplied to the electric engine. By supplying the electric engine with electric energy, the electric engine can be operated in motor mode and thus as an electric motor, so that the motor vehicle can be driven electrically, in particular purely electrically.

[0007] The fuel cell system may also have a cooling device, which may cool at least a portion of the fuel cell system. In particular, at least a portion of the cooling device may be supplied with, for example, a liquid coolant, which may cool at least a portion of the fuel cell system. The cooling device may also be referred to as a cooling system.

[0008] To enable particularly efficient, particularly energy-efficient operation of the fuel cell system and thus the vehicle, the method according to the present invention predicts, i.e., predictively determines, the energy consumption of the cooling device according to the vehicle's planned driving route, particularly by an electronic computing device of the vehicle. This is understood to mean, in particular, that the energy consumption is determined, particularly calculated, at a first time or during a first period of time, where the first time or period is while the vehicle is traveling or starting along the planned driving route, i.e., while actually traveling along the driving route, and precedes the second period of time. In other words, the energy consumption is determined before the vehicle travels along the driving route or while the vehicle is not (yet) traveling along the driving route. The driving route may include at least one or more refueling operations, also simply referred to as refueling. A refueling operation is, in particular, a planned refueling process that may be carried out in the future if necessary since the driving route is a planned driving route, during which hydrogen is filled into the tank, particularly from outside the tank, so that the tank is at least partially filled with hydrogen. For example, a refueling operation is necessary, or is assumed or determined, so that the vehicle can travel, in particular along the entire travel route. Furthermore, the planned travel route may include at least one or more stop times. In particular, since the travel route is a planned travel route, the stop times are planned stop times, which are times when the vehicle is, for example, particularly continuously stopped and / or the vehicle is not particularly continuously driven by the fuel cell system and / or the fuel cell system is not particularly continuously operating. In particular, during the stop times, discharging hydrogen from the hydrogen tank and / or supplying electrical energy by the fuel cell is omitted.In particular, the predicted energy consumption is a temporal energy consumption, and thus a temporal energy consumption curve of the energy consumption of the cooling device, the energy consumption or energy consumption curve being determined, calculated or estimated, thereby being a predicted energy consumption curve, which energy consumption curve characterizes the energy or amount of energy likely to be consumed by the cooling system when or while the vehicle is traveling along the travel route, i.e. when or while the vehicle is being driven.

[0009] In this method, the future time-pressure curve of the pressure that is or can be brought about by the hydrogen present in the hydrogen tank, in particular received or receivable in the hydrogen tank, is also predicted, i.e., is determined in advance or predicted, in particular depending on the driving route. The future time-pressure curve is therefore, for example, a planned, in particular specified or specifiable time-pressure curve, for example, the pressure curve is a set, i.e., a target curve that should result.

[0010] In the method according to the present invention, a future time-dependent energy curve of the amount of thermal energy to be supplied from the cooling device to the hydrogen tank according to an energy curve is also predicted in accordance with the predicted energy consumption to achieve the pressure curve. That is, the energy curve defines a time curve, which, taking into account the predicted energy consumption of the cooling device, determines the amount of thermal energy to be provided by the cooling device and thereby supplied to the hydrogen tank to achieve the pressure curve, particularly when the vehicle departs from or is traveling along a route. As a result, the cooling device can provide thermal energy to be supplied to the hydrogen tank during at least one or more sections of the route, so that the hydrogen tank is used as a thermal buffer or heat sink. Thus, excessively high thermal loads, i.e., excessively high temperatures in the cooling device, can be avoided without cooling the cooling device with a fan, particularly an electric fan. The method thus provides a method for predictive thermal or temperature regulation of a fuel cell system. The present invention is therefore based, inter alia, on the following findings and considerations: Generally, automobiles equipped with fuel cells, and therefore also referred to as fuel cell vehicles, use powerful cooling systems that can dissipate power losses from the fuel cell, especially during high load phases of the fuel cell, and maintain a relatively narrow temperature operating range of the fuel cell, i.e., ensure that the temperature of the fuel cell or fuel cells remains within its temperature operating range. Therefore, the cooling device is used, inter alia, to cool the fuel cell and thereby maintain the temperature operating range. For example, the temperature operating range is essentially at least ±8-10°C. In addition, in the case of fuel cell vehicles designed as heavy commercial vehicles, the cooling system also receives additional heat input from activated sustained braking devices, such as retarders, brake resistors, etc. In particular, the cooling system is also used to cool sustained braking devices, such as retarders, brake resistors, etc. of the vehicle. Conventionally, the cooling system (cooling device) simultaneously cools the retarder and the vehicle's fuel cell, at least for a certain time period.High load phases of a fuel cell system result in long startup periods, i.e., periods during which the electric fan operates, requiring or having a power of, for example, 30 or 40 kW. The aforementioned coolant is cooled by a fan, which is a component of a cooling device or cooling system, for example, via a heat exchanger, in particular by conveying air around a heat exchanger, for example, designed as an air-to-air heat exchanger, when the fan is operating. The heat exchanger transfers heat from the coolant to the air flowing around the heat exchanger and conveyed by the fan. Furthermore, a permanent heat flow may be required, for example, to heat cryogenic liquid hydrogen. This heat flow can be diverted from a heat source if the cooling system (chiller) is designed accordingly. For example, fuel cells and retarders can be used as heat sources, also known as waste heat, to heat hydrogen received or available in the hydrogen tank and / or hydrogen discharged from the hydrogen tank on the way to the fuel cell. Thus, in particular the hydrogen receivable or received in the hydrogen tank or the hydrogen tank can be used as a heat sink, for example by operating the aforementioned fan to buffer the heat, in particular waste heat, in the hydrogen tank during high load phases when the energy consumption of the cooling device is high, thereby moderating the cooling system (chiller) and thereby saving energy. That is to say, the method according to the invention makes it possible to extract heat, in particular waste heat, from the cooling device, in particular from the coolant, in a particularly efficient and effective manner, not only or only by operating the aforementioned fan, but in particular due to the fact that an amount of thermal energy is extracted from the cooling device, in particular from the coolant, according to an energy curve and supplied to the hydrogen tank, in particular the hydrogen received in the hydrogen tank.

[0011] The thermal energy quantity is or characterizes the thermal energy or heat that is discharged from the cooling device, in particular the cooling medium, thereby making it possible to avoid excessive temperatures in the cooling device without operating a fan. To discharge the thermal energy quantity (heat) from the cooling device, the thermal energy quantity (heat) is supplied to the hydrogen tank, which is therefore at least temporarily used as a thermal buffer or heat sink. In particular, if more heat is supplied into the hydrogen tank, i.e., if more heat is added to the hydrogen tank, the pressure in the hydrogen tank increases due to increased evaporation of hydrogen in the hydrogen tank. The pressure in the hydrogen tank must not increase above a limit value, in particular a predetermined limit value, in particular a tank load limit value, and the pressure in the hydrogen tank, also referred to as tank pressure, should be reduced before a refueling process, also referred to as a tank process, and / or particularly long stationary phases or stop times of the vehicle. The method according to the present invention here ensures energy savings, on the one hand, by selectively setting, in particular increasing, the tank pressure, and on the other hand, by matching the pressure ratio, in particular before the refueling process and / or the shutdown time, thereby realizing particularly advantageous and particularly efficient operation of the fuel cell system and the entire vehicle. The pressure curve and the energy curve are also called trajectories, in particular, the pressure curve is also called a pressure trajectory, and the energy curve is also called a thermal energy trajectory. The amount of thermal energy is, for example, the target amount of thermal energy supplied to the hydrogen tank, i.e., supplied to achieve, i.e., cause, the pressure trajectory. In this way, in the method, the pressure trajectory and the associated thermal energy trajectory are predictively determined. Furthermore, the energy consumption of the cooling device is predictively determined, in particular calculated, in order to determine at least one or more time intervals, i.e., phases, during which energy discharge, in particular of the cooling device, to the hydrogen tank is or should be performed. Energy discharge is understood to mean, in particular, during the respective phases, the amount of thermal energy, and therefore heat, provided by the cooling device and supplied to the hydrogen tank is or can be supplied to set, i.e., bring about, the predicted pressure curve.The present invention therefore allows the energy consumption of the fuel cell system, particularly with regard to thermal management, to be reduced compared to conventional solutions, and thereby the energy consumption of the entire vehicle, which can be operated in a particularly energy-efficient and cost-effective manner. Furthermore, overloading of the cooling system, which would otherwise involve shutting down components such as the drivetrain of the vehicle, can be at least delayed or avoided.

[0012] To achieve particularly efficient operation of the fuel cell system, and thus the entire vehicle, in an advantageous embodiment of the present invention, the pressure and energy curves, i.e., trajectories, are predicted in a first operating phase of the cooling device such that the predicted energy consumption is greater in the first operating phase than in a second operating phase of the cooling device, and more thermal energy is supplied from the cooling device to the hydrogen tank than in the second operating phase. This allows the hydrogen tank to be used effectively and efficiently, at least temporarily, as a thermal buffer, thereby avoiding excessive temperatures in the cooling device without the need to actively cool it, for example, with a so-called fan. This means, in particular, that the time integral of the energy curve in each first operating phase is greater than the second integral of the energy curve in each second operating phase. That is, the first portion of the thermal energy quantity is greater than the second portion of the thermal energy quantity, and the first portion is supplied to the hydrogen tank by the cooling device in each first operating phase, and the second portion is supplied to the hydrogen tank in each second operating phase. In particular, the first portion is greater than zero, and in this case the second portion is greater than or equal to zero.

[0013] It has been shown to be particularly advantageous if no transfer of thermal energy from the cooling device to the hydrogen tank occurs during at least one of the second operating phases. On the one hand, this can effectively and efficiently prevent excessive temperatures in the cooling device, and on the other hand, it can avoid excessive pressure buildup in the hydrogen tank.

[0014] A further embodiment is characterized in that the pressure curve is predicted in such a way that the pressure over the entire pressure curve is always, i.e. continuously, below a maximum pressure, in particular a predetermined maximum pressure, so that thermal energy can be transferred effectively and efficiently from the cooling device to the hydrogen tank, while safely avoiding excessive stress or damage to the hydrogen tank.

[0015] In order to be able to use the hydrogen tank particularly effectively and efficiently as a thermal buffer, a further embodiment of the invention provides that at least the pressure curve is predicted as a function of at least one refueling process provided for filling the hydrogen tank and / or as a function of at least one stoppage time of the vehicle, during which the vehicle is stopped, not driven by the fuel cell system and in particular not traveling, in particular the refueling process and / or the stoppage time being part of a planned travel route.

[0016] A second aspect of the invention relates to a motor vehicle, preferably in the form of a commercial vehicle, in particular a lorry, also called simply a vehicle, designed to carry out the method according to the first aspect of the invention.

[0017] For example, the pressure trajectory and the thermal energy trajectory, i.e., the pressure curve and the energy curve, are determined, i.e., predicted, such that during high load phases when the energy consumption of the cooling device increases, more heat is discharged from the cooling device to the hydrogen tank, i.e., supplied to the hydrogen tank, where preferably a maximum pressure that is or characterizes the maximum pressure limit is maintained, i.e., the tank pressure is always less than or equal to the maximum pressure.

[0018] For example, the pressure trajectory and the thermal energy trajectory are determined, particularly predicted, in partial and / or low load phases of the cooling device, e.g., in each partial and / or low load phase, the cooling device consumes less energy than in each high load phase, and therefore the heat supply from the cooling device to the hydrogen tank, and thus the supply of thermal energy from the cooling device to the hydrogen tank, is reduced, i.e., adjusted or completely stopped, i.e., prevented, particularly compared to each high load phase, in order to allow a pressure drop in the hydrogen tank, i.e., a reduction in the pressure in the hydrogen tank, particularly compared to each high load phase, during the partial and / or low load phases, e.g., as a result of hydrogen consumption that takes place during the transfer of hydrogen from the hydrogen tank and its supply to the fuel cell. For example, the hydrogen consumption along the driving route and the pressure curve of the pressure in the hydrogen tank, also known as pressure evolution, are known, i.e., a predictive determination, particularly calculation, and therefore predictively planned manner of the driving route, also known as a tour, can be performed. That is, for example, the planned driving route includes in particular the expected consumption of hydrogen from the hydrogen tank by the fuel cell system and / or at least one other further consumption.

[0019] For example, if a refueling process is not planned or known, a possible refueling process can be envisaged when the amount of hydrogen, also called the filling level, in the hydrogen tank falls below a threshold, a predetermined or determinable threshold, and the above-mentioned function for buffering waste heat from the cooling device in the hydrogen tank is throttled, i.e., reduced or reduced, or completely prevented, i.e., deactivated.

[0020] Further advantages, features and details of the invention will become apparent with reference to the following description of preferred exemplary embodiments and the drawings, in which: Features and combinations of features mentioned above in the description, as well as features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the combination shown in each case, but also in other combinations or alone, without departing from the scope of the invention. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a schematic diagram of a fuel cell system for a motor vehicle, preferably in the form of a commercial vehicle, in particular a heavy goods vehicle. [Figure 2] 3 is a flow chart illustrating a method for operating the automotive fuel cell system shown schematically in FIG. 2. [Figure 3] 1 is a partial schematic cross-sectional view of a tank system of a fuel cell system consisting of a hydrogen tank. DETAILED DESCRIPTION OF THE INVENTION

[0022] In the drawings, identical or functionally identical elements are provided with the same reference numbers.

[0023] 1 shows a fuel cell system 10 for a motor vehicle 12, which is shown schematically in Figure 2, in the form of a commercial vehicle, in particular a heavy goods vehicle. In the following, a method for operating the fuel cell system 10 will be described with reference to Figures 1 to 3, by means of which a particularly efficient and particularly energy-efficient operation of the fuel cell system 10, and thus of the motor vehicle 12 as a whole, can be achieved.

[0024] From FIG. 1, it can be seen that the fuel cell system 10 has at least one hydrogen tank 14, which is particularly shown diagrammatically in FIG. 1 and is also simply referred to as a tank, and which can receive or receives hydrogen. In conjunction with FIG. 3, it can be seen that the hydrogen tank 14 is a component of a tank system 16, also referred to as a tank arrangement, which will be described in more detail below. Since the hydrogen is received in the hydrogen tank 14 under pressure, a pressure, also referred to as a tank pressure, caused by the hydrogen received in the hydrogen tank 14 exists in the hydrogen tank 14, and this pressure may be, for example, in the range of 6 bar to 15 bar (inclusive), and in particular must be in this range. In particular, the hydrogen tank 14 contains both liquid and gaseous hydrogen phases. The fuel cell system 10 also includes at least one fuel cell 18 that can receive hydrogen from the hydrogen tank 14, as indicated by arrow 20 in FIG. 1. For this purpose, hydrogen is discharged from the hydrogen tank 14 and supplied to the fuel cell 18, in particular in a gaseous state. The fuel cell 18 may be understood to be, for example, a fuel cell stack, or the fuel cell 18 may be understood to be a component of a fuel cell stack, which may have multiple fuel cells 18 .

[0025] Waste heat, also simply referred to as heat, is indicated by arrows 22 and 24 and is discharged or supplied from the fuel cell 18 during operation, for example. Waste heat, also simply referred to as heat, is indicated by arrow 26 and is discharged or supplied from at least one sustained braking device 28 of the vehicle 12, particularly during operation of a sustained braking system 28. The vehicle 12 can be braked by the sustained braking device 28, for example, designed as a retarder, particularly so that the speed at which the vehicle 12 travels along the road does not increase or decrease. For example, the waste heat of the fuel cell 18 and the sustained braking device 28 constitute the total waste heat. For example, arrow 22 indicates that a first portion of the total waste heat is discharged to a cooling device 30, also referred to as a cooling system, of the fuel cell system 10, particularly shown schematically in FIG. 1 , in such a way that the first portion of the total waste heat is transferred to the coolant of the cooling device 30, for example, via a heat exchanger. Thus, the fuel cell 18 and, preferably, also the sustained braking device 28, are cooled by the cooling device 30. It is shown that a second portion of the total waste heat can be transferred to the hydrogen tank 14 and thus to the hydrogen received in the hydrogen tank 14, particularly via a heating device 32, also referred to as a heater, of the fuel cell system 10, as shown diagrammatically in FIG. 1 . As a result, the second portion of the total waste heat is directed away from the cooling device 30, i.e., is not discharged by the cooling device 30, as indicated by the arrow 24. This advantageously keeps the heat load of the cooling device 30 low. The cooling device 30 has a cooling circuit through which a coolant can flow. For example, the cooling device 30 includes, among other things, an electrically operated fan capable of transporting air. The air can flow, for example, around a radiator through which the coolant flows. As a result, heat is transferred from the coolant via the radiator to the air transported by the fan, which flows around the radiator and can cool the coolant.As illustrated by arrows 22 and 24, not all of the waste heat is discharged to or through the cooling device 30, but rather a second portion of the total waste heat is transferred to the hydrogen tank 14 and thus, for example, buffered by the hydrogen tank 14, so that, for example, excessively long operating times of the fan over the entire period can be kept advantageously low, resulting in a particularly efficient and particularly energy-efficient operation of the cooling device 30 and thus of the fuel cell system 10 as a whole.

[0026] As illustrated by arrow 34 in FIG. 1 , transferring heat, i.e., the second portion of the total waste heat, to the hydrogen tank 14 causes vaporization of the liquid hydrogen contained in the hydrogen tank 14, i.e., vaporization of at least a portion of the liquid phase of hydrogen in the hydrogen tank 14, thereby increasing the tank pressure. As will be explained in more detail below, the hydrogen tank 14, and in particular the tank system 16, can be used to buffer the waste heat, i.e., the second portion of the total waste heat in the hydrogen tank 14, during high-load phases when the cooling device 30 consumes a large amount of energy, thereby reducing the load on the cooling device 30, thereby saving energy, in particular electrical energy. For this purpose, as will be explained in more detail below, the energy consumption of the cooling device 30 is predicted according to a planned, e.g., predicted, driving route of the vehicle 12. Furthermore, a future time-dependent pressure curve of the pressure currently occurring in the hydrogen tank 14, i.e., the tank pressure, is predicted. For example, the energy consumption and the pressure curve, also referred to as the pressure trajectory, are predicted, i.e., predictively determined, by an electronic computing device, in particular by the vehicle 12. Furthermore, particularly by means of an electronic computing device, a future time energy curve, also called energy trajectory or thermal energy trajectory, of the amount of thermal energy is predicted in order to realize the pressure curve. The amount of thermal energy is, i.e., is intended to be or should be, supplied in accordance with the energy curve by the cooling device 30, for example, to the hydrogen tank 14 via the cooling device 30, in accordance with the predicted energy consumption. The amount of thermal energy is therefore heat, i.e., the thermal energy or amount of thermal energy, illustrated, for example, by the arrow 24 in FIG. 1 . That is, the arrow 24 indicates, for example, the second portion of the total waste heat, the amount of thermal energy that can be or is supplied by the cooling device 30, for example, via or by a coolant, in accordance with the predicted energy curve, to the hydrogen tank 14 in accordance with the predicted energy consumption, in order to realize the pressure curve, in particular while the vehicle 12 is traveling along the planned driving route, in particular while it is actually traveling.

[0027] In FIG. 2 , a planning module, also called a logistics plan or designed to execute the logistics plan, is particularly diagrammatically illustrated and referenced 35. For example, a driving route, also called a tour, is planned, i.e., planned predictively, by the planning module 35. For example, the planning module 35 determines when, i.e., at what time or during what period, the vehicle 12 will travel along a driving route, also called a stretch; where, i.e., at what point along the driving route, the vehicle 12 will be refueled, i.e., a refueling process will be performed; and when, i.e., at what point along the driving route the vehicle 12 will be interrupted or where a stop is planned, i.e., performed. The refueling process, also called a tank process, is a process in which hydrogen is filled into the hydrogen tank 14, in particular from outside the hydrogen tank 14, and in particular from outside the vehicle 12 as a whole. Each stop is a period or time interval during which the vehicle 12 is stopped and therefore not driven by the fuel cell system 10, so that, for example, during each stop, the discharge of hydrogen from the hydrogen tank 14, in particular to the fuel cell 18, is omitted. When planning a travel route, other parameters characterizing the travel route or the vehicle 12 along the travel route are taken into account, such as the payload of the vehicle 12 and / or the planned operation of the vehicle 12, e.g., a refrigerated body for cooling the cargo compartment of the vehicle 12.

[0028] Arrow 36 indicates that relevant, in particular all relevant, tour planning data characterizing the planned driving route is transmitted to and received by driving strategy module 38. Driving strategy module 38 determines and, in particular, calculates, for example, a driving strategy, in particular an overall driving strategy for the planned driving route, also referred to as a tour. For example, the driving strategy is determined predictively, i.e., a planned driving strategy, which is the driving or operation of fuel cell system 10, in particular when vehicle 12 is actually driving along the driving route. This includes, for example, the torque provided by the drive unit to drive vehicle 12 and thus travel along the driving route, also referred to as a driving stretch, so that vehicle 12 can complete the driving route, and also includes the power output of fuel cell 18, also referred to as fuel cell power, in particular a target trajectory derived from the state-of-charge curve of the associated buffer battery of vehicle 12. The drive unit may, for example, consist of at least one electric engine and may drive vehicle 12 electrically, in particular purely electrically, to drive vehicle 12 along the driving route. The buffer battery is a battery, in particular a secondary battery, in which electrical energy provided or available from, for example, the fuel cell 18 is at least temporarily stored, i.e., buffered. For example, a drive device, in particular an electric engine, can be supplied with electrical energy provided by the fuel cell 18 and / or electrical energy stored in the battery, so that the vehicle 12 is electrically driven by the electric engine. The driving strategy takes into account at least one or more sustained braking systems of the vehicle 12, such as, for example, sustained application brakes 28. That is, the driving strategy also includes, for example, a strategy for activating the sustained braking device 28 along the driving route, which sustained braking device 28 generates or can generate additional heat input, in particular to the cooling device 30, as described above.

[0029] Furthermore, a pressure curve and an energy curve are predicted. The amount of thermal energy is a target amount of thermal energy that should be supplied to the hydrogen tank 14, in particular when the vehicle 12 is traveling along the travel route, in order to bring about, i.e., achieve, the pressure curve. By predicting the energy consumption of the cooling device 30, it is possible to determine the driving stages, also simply called phases, during which energy is discharged in the hydrogen tank 14 while the vehicle 12 is traveling along the travel route, and thus the amount of thermal energy that can be supplied to the hydrogen tank 14. In particular, by analyzing the driving times, travel durations, and usual driving and stopping habits, it is possible to anticipate, i.e., predict, stopping times, if necessary.

[0030] The determined, in particular calculated, driving strategy is transmitted, in particular by the driving strategy module 38, to the thermal management module 42 and received by the thermal management module 42, as illustrated by arrow 40. For example, the driving strategy module 38 and / or the thermal management module 42 are part of the aforementioned electronic computing device.

[0031] The pressure trajectory and the thermal energy trajectory, also simply referred to as trajectories, are target trajectories. The thermal management module 42 is designed to implement the target trajectory, i.e., to realize the target trajectory, strategically determined in advance, particularly calculated, by which the fuel cell system 10 is operated, particularly controlled or regulated, by implementing the target trajectory, i.e., to operate or drive the fuel cell system 10 according to the predicted target trajectory. This is achieved, for example, by the thermal management module 42 controlling actuators 46, also known as actuator systems or thermal system actuators, of the fuel cell system 10, as illustrated by arrows 44. The actuators 46 include, for example, valves, pumps, and at least one or more fans, such as the aforementioned fans. Sensors 48, also known as thermal system sensors, are also provided. As illustrated by arrows 50, sensors 48 can detect measurement variables, such as the pressure and / or temperature of fuel cell system 10, and transmit them to thermal management module 42. Depending on the measurement variables detected by sensors 48, thermal management module 42 activates, i.e., operates, in particular controls or adjusts, fuel cell system 10, in particular actuators 46, to implement a target trajectory, i.e., to operate fuel cell system 10 according to the target trajectory. One of the measurement variables is, for example, the aforementioned tank pressure. One of the other measurement variables is, for example, another pressure of fuel cell system 10. Furthermore, the measurement variables may include at least one or more temperatures of fuel cell system 10. The respective pressures are, for example, detected by respective pressure sensors. The respective temperatures are, for example, detected by respective temperature sensors. For example, by thermal management module 42, adjustments of fuel cell system 10, in particular actuators 46, are performed at predetermined or specifiable target values, in particular so that the target trajectory is actually implemented. If predictively calculated target requirements, such as tank pressure and / or coolant temperature, are not or cannot be achieved, the predictive operating strategy is redetermined, and in particular recalculated, as illustrated by arrow 52.This can be done in particular by the driving strategy module 38, and in particular based on new state data, for example detected by the sensors 48 and thus determined by the thermal management module 42, and in particular transmitted to and received by the driving strategy module 38, as illustrated by arrow 52. This may be performed, for example, periodically, in particular based on the current state and measurements of the vehicle 12 in each case. For example, the coolant comprises at least water, and therefore the coolant may also be called, for example, coolant.

[0032] For example, as shown by arrow 54, the thermal management module 42 can transmit at least one or more requirements for heating the hydrogen tank 14 to the operation module 56 for operating, in particular regulating or controlling, the tank system 16, i.e., for supplying an amount of thermal energy to the hydrogen tank 14 according to an energy curve, thereby warming, i.e., heating, the hydrogen tank 14. For example, the operation module 56 can be a component of an electronic computing device. The operation module 56 can be called, for example, a tank control module or a tank regulation module. For example, as shown by arrow 54, a request for heat evacuation from the hydrogen tank 14 is transmitted from the thermal management module 42 to the operation module 56, in particular at a desired time or during a desired period, and is received by the operation module 56. The operation module 56 implements the requirements provided by the thermal management module 42 and receives them, in particular within a range of possibilities and / or within an allowable pressure range, corresponding, for example, to the aforementioned range of 6 to 15 bar, and reports this implementation to the thermal management module 42, as shown by arrow 58. This report includes, for example, the estimated amount of heat to be discharged from or by the hydrogen tank 14 based on demand, and the tank pressure, in particular the actual pressure prevailing in the hydrogen tank 14 and caused in particular by the hydrogen contained therein. A central, i.e., effective, control or regulation element, i.e., for regulating the heat flow in the hydrogen tank 14, i.e., the amount of thermal energy supplied to the hydrogen tank 14, is, for example, a valve 60, particularly shown diagrammatically in FIG. 2, for example, a pressure valve, particularly designed as a pressure control valve or pressure regulating valve, which is activated, and thus operated, in particular regulated or controlled, by the operating module 56. For example, the flow or flow of hydrogen, in particular gaseous hydrogen, through a heat exchanger 62, shown in FIG. 3, is regulated by the valve 60. The heat exchanger 62 is a component of the tank system 16 and will be described in more detail below. For example, when the valve 60 is fully open, this allows a maximum heat flow into the hydrogen tank 14.When the valve 60 is closed, the hydrogen tank 14 is for example (no longer) heated, which occurs especially in the case of partial load, whereby for example the tank pressure drops (again).

[0033] Compared to conventional solutions, the energy consumption of the fuel cell system 10 can be reduced by this method, which can keep the overall energy consumption of the vehicle 12 particularly low. The vehicle 12 can therefore be operated in a particularly cost-effective manner. Furthermore, overloading of the cooling device 30, which would entail shutting down components such as the drive, can be delayed or avoided altogether.

[0034] The cooling device 30 includes, for example, a cooling circuit 64 through which a coolant can flow, of which conduit elements 66 and 68 are partially shown in FIG. 3 . The conduit elements 66 and 68 allow the coolant to flow. The conduit element 66 can supply the heat-containing coolant, such as a second portion of the total waste heat, to the heat exchanger 62. For example, a valve 70 disposed within the conduit element 66 can be used to regulate the flow of the coolant through the conduit element 66, particularly toward the heat exchanger 62. The valve 70 can be controlled by the thermal management module 42, which can then regulate, particularly control or adjust, the flow of the coolant through the conduit element 66 toward the heat exchanger 62 via the valve 70. The coolant can be discharged from the heat exchanger 62 via the conduit element 68.

[0035] The hydrogen tank 14 can be vented via a ventilation line 72, and can be refueled via a tank device 74. A blow-off line is referenced 76, a valve, for example, designed as a tank valve, is referenced 78, and a valve, for example, configured as a safety valve, is indicated by 80. For example, hydrogen is discharged from the hydrogen tank 14 via a conduit element 82 and supplied, in particular, to the fuel cell 18. It can be seen that the operating module 56 can, for example, control and thus operate the valves 78 and 60, and that the operating module 56 can, for example, control and operate the heat exchanger 62. The aforementioned temperature sensor is referenced 84 in FIG. 3, and the aforementioned pressure sensor is referenced 86. The amount of hydrogen received (again) in the hydrogen tank 14 can be detected by a detection means 88, which is also referred to as the filling level. The detection means 88 can provide at least one signal, in particular an electrical signal, characterizing the filling level, which signal can be received by the operating module 56. The operation module 56 can report the detected temperature, the detected pressure, and the detected filling level to the operation strategy module 38, which can then create requirements and specify them to the operation module 56, so that, for example, the tank system 16 can be operated, particularly controlled or regulated, by the thermal management module 42 and by the operation module 56, particularly depending on the detected temperature, depending on the detected pressure, and depending on the detected filling level, particularly so that the target trajectory is actually implemented, i.e., realized.

[0036] 3, the heat contained in the coolant, i.e., the aforementioned second portion of the total waste heat, can be transferred to the hydrogen tank 14, particularly the hydrogen therein, via the heat exchanger 62, thereby warming, i.e., heating, the hydrogen tank 14 and thus the hydrogen received therein. This allows the hydrogen tank 14 to be used at least temporarily as a thermal buffer, thereby advantageously keeping the energy consumption of the cooling device 30 low. Furthermore, for example, the heat contained in the coolant, i.e., the second portion of the total waste heat, can be transferred via the heat exchanger 62 to the hydrogen, particularly in a gaseous state, flowing through the conduit element 82, which, for example, discharges the hydrogen tank 14 and supplies it to the fuel cell 18. As a result, the particularly gaseous hydrogen supplied to the fuel cell 18 can be heated, particularly preheated, on its way to the fuel cell 18, so that the second portion of the waste heat can be advantageously discharged, particularly without operating the aforementioned fan. [Explanation of symbols]

[0037] 10. Fuel Cell System 12. Automobiles 14 Hydrogen Tank 16 Tank System 18 Fuel Cell 20 Arrows 22 Arrow 24 Arrow 26 Arrow 28 Sustained braking device 30 Cooling device 32 Heating device 34 Arrow 35 Planning Module 36 Arrow 38 Driving Strategy Module 40 Arrow 42 Thermal Management Module 44 Arrow 46 Actuator 48 sensors 50 Arrows 52 Arrow 54 Arrow 56 Driving Module 58 Arrow 60 valves 62 Heat exchanger 64 Cooling circuit 66 Conduit Element 68 Conduit element 70 valves 72 Ventilation pipe 74 Tank Equipment 76 Blow-off pipe 78 Valve 80 valves 82 Conduit element 84 Temperature Sensor 86 Pressure Sensor 88 Detection Methods

Claims

1. A method for operating a fuel cell system (10) of a motor vehicle (12), the fuel cell system (10) comprising at least one hydrogen tank (14), at least one fuel cell (18) capable of receiving hydrogen from the hydrogen tank (14), and a cooling device (30) for cooling at least one portion of the fuel cell system (10), the method comprising: the energy consumption of the cooling device (30) is predicted depending on the planned driving route of the vehicle (12); - the future time pressure curve of the pressure prevailing in said hydrogen tank (14) is predicted, and - a future time energy curve of the amount of thermal energy that can be supplied from the cooling device (30) to the hydrogen tank (14) according to an energy curve is predicted depending on the predicted energy consumption to realize the pressure curve.

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

3. 3. The method of claim 2, wherein during at least one of the second operating stages, no transfer of thermal energy from the cooling device (30) to the hydrogen tank (14) occurs.

4. A method according to any one of claims 1 to 3, characterized in that the pressure curve is predicted in such a way that the pressure is always below a maximum pressure over the entire pressure curve.

5. 5. The method according to claim 1, wherein at least the pressure curve is predicted as a function of at least one refueling process provided for filling the hydrogen tank (14) and / or as a function of at least one stop time of the motor vehicle (12).

6. A motor vehicle (12) configured to carry out the method according to any one of claims 1 to 5.

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