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

Abstract

The invention relates to a method for operating a fuel cell system (10) of a motor vehicle (12), the fuel cell system (10) of which has at least one hydrogen tank (14), at least one fuel cell (18) that is able to 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 an energy consumption of the cooling device (30) is predicted depending on a planned route of the motor vehicle (12), a future, temporal pressure profile of a pressure prevailing in the hydrogen tank (14) is predicted, and a future, temporal energy profile of a quantity of heating energy which is to be supplied to the hydrogen tank (14) according to the energy profile of the cooling device (30), depending on the predicted energy consumption, is predicted, in order to realize the pressure profile.

Description

[0001] Method for operating a fuel cell system of a motor vehicle, in particular a commercial vehicle, and motor vehicle

[0002] The invention relates to a method for operating a fuel cell system of a motor vehicle, in particular a commercial vehicle. The invention further relates to a motor vehicle, in particular a commercial vehicle.

[0003] WO 2016 / 083365 A1 discloses a method for the predictive operation of a motor vehicle with a fuel cell system.

[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 so that particularly efficient operation can be realized.

[0005] This object is achieved by a method having the features of patent claim 1 and by a motor vehicle having the features of patent claim 6. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims.

[0006] A first aspect of the invention relates to a method for operating a fuel cell system of a motor vehicle, preferably designed as a commercial vehicle, in particular as a truck, and also simply referred to as a vehicle. The fuel cell system has at least one hydrogen tank, which is also simply referred to as a tank. Hydrogen (H2) can be or is accommodated in the hydrogen tank. The fuel cell system, also referred to as a fuel cell device or fuel cell apparatus, further comprises at least one fuel cell, which can be supplied with hydrogen from the hydrogen tank. As is well known, the fuel cell can be used to convert chemical reaction energy of the hydrogen, which is supplied to the fuel cell, and of an oxidizing agent into electrical energy, which can be provided by the fuel cell.Oxygen is used in particular as the oxidizing agent, which is contained, for example, in air, which can also be or is supplied to the fuel cell. The electrical energy provided or that can be provided by the fuel cell can, for example, be stored at least temporarily in an electrical energy store, which is designed in particular as a battery, very particularly as a secondary battery. Furthermore, it is conceivable that at least one electrical machine can be or is supplied with the electrical energy that can be or is provided by the fuel cell, in particular directly and thus bypassing the electrical energy store, wherein it is alternatively or additionally conceivable that the electrical machine can be supplied with the electrical energy that is stored in the electrical energy store.By supplying the electric machine with electrical energy, the electric machine can be operated in motor mode and thus as an electric motor, by means of which the motor vehicle can be driven, in particular purely electrically.

[0007] The fuel cell system also has a cooling device, by means of which at least a portion of the fuel cell system can be cooled. In particular, at least a portion of the cooling device can be flowed through by a coolant, for example, a liquid coolant, by means of which at least the portion of the fuel cell system can be cooled. The cooling device is also referred to as the cooling system.

[0008] In order to be able to realize particularly efficient, in particular energy-efficient, operation of the fuel cell system and thus of the motor vehicle, the method according to the invention provides that, in particular by means of an electronic computing device, in particular of the motor vehicle, an energy consumption of the cooling device is predicted, i.e. forecasted, and thus determined in advance, as a function of a planned route of the motor vehicle. This is to be understood in particular that the energy consumption is determined, in particular calculated, at a first point in time or during a first period of time, wherein the first point in time or the first period of time precedes a second period of time during which the motor vehicle travels or travels the planned route, i.e. actually travels along the route.In other words, the energy consumption is determined before the motor vehicle travels along the route or before the motor vehicle has (yet) traveled along the route. The route can comprise at least one or more refueling processes, also simply referred to as refuelings. The refueling process is, in particular, because the route is a planned route, a planned refueling process that may take place in the future, during which hydrogen is filled into the tank, in particular from outside the tank, and the tank is therefore at least partially filled with hydrogen. For example, the refueling process is necessary or assessed or determined as necessary so that, for example, the motor vehicle can travel the route, in particular the entire route. Furthermore, it is conceivable that the planned route includes at least one or more downtimes.The downtime is, in particular, a planned downtime due to the fact that the route is a planned route, during which the motor vehicle, for example, is stationary, in particular continuously, and / or the motor vehicle is not driven by the fuel cell system, in particular continuously, and / or the fuel cell system is not operated, in particular continuously. In particular, during the downtime, hydrogen can be removed from the hydrogen tank and / or electrical energy can be provided by the fuel cell.In particular, the predicted energy consumption is a temporal energy consumption, thus a temporal energy consumption profile of an energy consumption of the cooling device, wherein the energy consumption or the energy consumption profile is a determined, calculated or estimated and thereby predicted energy consumption profile, which characterizes an energy or amount of energy that is likely to be consumed by the cooling system when or while the motor vehicle is traveling along the route, i.e. is being driven.

[0009] The method also predicts, i.e., anticipates or predicts, a future temporal pressure profile prevailing in the hydrogen tank and in particular caused or induced by the hydrogen stored or capable of being stored in the hydrogen tank, particularly as a function of the route. The future temporal pressure profile is thus, for example, a planned, in particular predefined or predeterminable, temporal pressure profile, wherein, for example, the pressure profile is a target profile that is to be set, i.e., to be achieved.

[0010] In the method according to the invention, a future, temporal energy profile of a heating energy quantity is also predicted, which, according to the energy profile, is to be supplied by the cooling device to the hydrogen tank depending on the predicted energy consumption, i.e., is to be supplied in order to realize the pressure profile. In other words, the energy profile indicates a temporal profile according to which, taking into account the predicted energy consumption of the cooling device, the said heating energy quantity is to be or is to be provided by the cooling device and is to be or is to be supplied to the hydrogen tank, in particular while the motor vehicle is traveling or driving along the route, in order to thereby realize the pressure profile.This allows the cooling device to provide thermal energy in at least one or more sections of the route, which is then fed to the hydrogen tank, so that the hydrogen tank is used as a heat buffer or heat sink. This allows excessive thermal stress, i.e., an excessively high temperature of the cooling device, to be avoided without having to actively cool the cooling device, for example, using a fan, particularly an electric fan. The method is thus a method for predictive heat or thermal control of the fuel cell system.The invention is based in particular on the following findings and considerations: Typically, a motor vehicle equipped with a fuel cell, and thus also referred to as a fuel cell vehicle, uses a powerful cooling system that can dissipate power losses from the fuel cell, particularly during high-load phases of the fuel cell, and can ensure that a relatively narrow temperature operating window of the fuel cell is maintained, thus ensuring that the fuel cell or a temperature of the fuel cell remains within the temperature operating window. Thus, 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 a fuel cell vehicle designed, for example, as a heavy commercial vehicle, the cooling system may also be subjected to additional heat input from activated sustained brakes, for example those designed as a retarder, brake resistor, etc., in particular because the cooling system is also used, for example, to cool a sustained brake of the vehicle, designed, for example, as a retarder or brake resistor. Conventionally, the cooling system (cooling device) therefore cools a sustained brake and also the vehicle's fuel cell simultaneously, at least for a time interval. During high-load phases of the fuel cell, this can result in long activations, i.e. long periods in which an electrically driven fan is operated, which requires or has, for example, an output of up to 30 or 40 kW.By means of the fan, which can be a component of the cooling device or cooling system, the aforementioned coolant is cooled, for example, in particular via a heat exchanger. In particular, when the fan is activated, it conveys air that flows around the heat exchanger, which is designed, for example, as an air-coolant heat exchanger. Heat is transferred via the heat exchanger from the coolant to the air flowing around the heat exchanger and conveyed by the fan. In addition, a particularly permanent heat flow may be required, for example to heat up the cryogenic, liquid hydrogen. This heat flow can be diverted from a heat supply from heat sources if the cooling system (cooling device) is designed accordingly.The fuel cell and the continuous brake, for example, can be used as heat sources whose heat, also referred to as waste heat, can be used to heat the hydrogen absorbed or absorbable in the hydrogen tank, for example, and / or the hydrogen discharged from the hydrogen tank on its way to the fuel cell. The hydrogen absorbed or absorbed in particular in the hydrogen tank, or the hydrogen tank itself, can thus be used as a heat sink, for example, during peak load phases with high energy consumption of the cooling device, e.g., by operating the aforementioned fan, to relieve the cooling system (cooling device) by buffering heat, in particular waste heat, in the hydrogen tank, and thus save energy.In other words, the method according to the invention makes it possible in a particularly efficient and effective manner to dissipate heat, in particular waste heat, from the cooling device, in particular from the coolant, but not or not only by operating the aforementioned fan, but in particular by dissipating the amount of heating energy according to the energy profile from the cooling device, in particular from the coolant, and supplying it to the hydrogen tank, in particular to the hydrogen stored in the hydrogen tank.

[0011] The amount of heating energy is or characterizes heating energy or heat that is dissipated by the cooling device, in particular by the coolant, whereby an excessive temperature of the cooling device can be avoided without operating the fan. In order to dissipate the amount of heating energy (heat) from the cooling device, the amount of heating energy is supplied to the hydrogen tank, which is thus used at least temporarily as a heat buffer or heat sink. If heat is fed into the hydrogen tank, in particular in an increased amount, i.e., if heat is supplied to the hydrogen tank, in particular in an increased amount, the pressure in the hydrogen tank rises due to increasing evaporation of the hydrogen in the hydrogen tank (tank).The pressure in the hydrogen tank should not exceed a particular predeterminable or predetermined limit, in particular the tank's load limit, 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 refueling procedure, and / or a particularly extended stationary phase or standstill period of the motor vehicle. The method according to the invention can now ensure energy savings through targeted adjustment, in particular increase, of the tank pressure on the one hand and, in particular, appropriate pressure conditions before refueling processes and / or standstill periods on the other hand, so that particularly advantageous and particularly efficient operation of the fuel cell system and the motor vehicle as a whole can be realized.The pressure curve and the energy curve are also referred to as trajectories, in particular such that 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 quantity is, for example, a target heating energy quantity that is to be supplied to the hydrogen tank, i.e. should be supplied, in order to thereby realize, i.e. bring about, the pressure trajectory. Thus, the method predictively determines the pressure trajectory and the associated heating energy trajectory. In addition, 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, in which energy dissipation, in particular from the cooling device, into the hydrogen tank can or should take place.Energy dissipation means that, particularly during the respective phase, the amount of heating energy and thus heat is or can be provided by the cooling device and supplied to the hydrogen tank in order to thereby set, i.e. bring about, the predicted pressure profile. The invention thus makes it possible to reduce the energy consumption of the fuel cell system, particularly with regard to thermal management, compared to conventional solutions, whereby the energy consumption of the entire motor vehicle can be reduced compared to conventional solutions. This allows the motor vehicle to be operated in a particularly energy-efficient and cost-effective manner. Furthermore, overloading of the cooling device with the associated shutdown of components such as a motor vehicle's drive can at least be delayed or avoided.

[0012] In order to achieve particularly efficient operation of the fuel cell system and thus of the motor vehicle as a whole, an advantageous embodiment of the invention provides for the pressure curve and the energy curve, thus the trajectories, to be predicted such that in the first operating phases of the cooling device, where the predicted energy consumption is greater in the first operating phases than in the second operating phases of the cooling device, greater heat energy is supplied to the hydrogen tank by the cooling device than in the second operating phases. As a result, the hydrogen tank can be used, at least temporarily, effectively and efficiently as a heat buffer, thereby preventing excessive temperatures in the cooling device without having to actively cool the cooling device, for example, using the 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, a first portion of the heating energy quantity is greater than a second portion of the heating energy quantity, with the first portion being supplied to the hydrogen tank by the cooling device in the respective first operating phase and the second portion being supplied to the hydrogen tank in the respective second operating phase. In particular, the first portion is greater than zero, and the second portion can be greater than or equal to zero.

[0013] It has proven particularly advantageous if, in at least one of the second operating phases, the transfer of heat energy from the cooling system to the hydrogen tank is avoided. On the one hand, this effectively and efficiently prevents excessive temperatures in the cooling system. On the other hand, it prevents an excessive pressure increase in the hydrogen tank.

[0014] A further embodiment is characterized by the fact that the pressure curve is predicted in such a way that the pressure is always, i.e., consistently less than or equal to a predetermined or predeterminable maximum pressure throughout its entire pressure curve. This allows heat energy to be effectively and efficiently transferred from the cooling device to the hydrogen tank, while simultaneously reliably avoiding excessive loads or damage to the hydrogen tank.

[0015] In order to be able to use the hydrogen tank particularly effectively and efficiently as a heat 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 intended for filling the hydrogen tank and / or as a function of at least one standstill period of the vehicle, which is stationary during the standstill period and is not powered by the fuel cell system, in particular, is not moving. In particular, the refueling process and / or the standstill period are part of the planned route.

[0016] A second aspect of the invention relates to a motor vehicle preferably designed as a commercial vehicle, in particular as a truck, which is also simply referred to as a vehicle and is designed to carry out a method according to the first aspect of the invention.

[0017] For example, the pressure trajectory and the heating energy trajectory, thus the pressure curve and the energy curve, are determined, i.e. predicted, in such a way that in high-load phases with increased energy consumption of the cooling device, more heat is dissipated from the cooling device into the hydrogen tank, thus being supplied to the hydrogen tank, wherein preferably the maximum pressure, which is or characterizes a maximum pressure limit, is maintained, thus the tank pressure is always less than or equal to the maximum pressure.

[0018] For example, the pressure trajectory and the heating energy trajectory are determined, in particular predicted, in such a way that in partial and / or low-load phases, in particular of the cooling device, wherein, for example, in the respective partial and / or low-load phase, the cooling device has a lower energy consumption than in the respective high-load phase, a heat supply from the cooling device to the hydrogen tank, thus the supply of the heating energy quantity from the cooling device to or into the hydrogen tank, is reduced, i.e. throttled or completely stopped, i.e. prevented, in particular compared to the respective high-load phase, in order to thereby enable a pressure reduction in the hydrogen tank, thus a reduction in the pressure in the hydrogen tank, in particular compared to the respective high-load phase, in particular by hydrogen consumption taking place during the partial and / or low-load phase.in which hydrogen is removed from the hydrogen tank and, for example, fed to the fuel cell. For example, through the planning, i.e., a predictive determination, in particular calculation, of the route, also referred to as a tour, the hydrogen consumption along the route and the pressure curve in the hydrogen tank, also referred to as pressure development, are known and can thus be implemented in a predictive manner. In other words, the planned route includes, for example, a predictive consumption of hydrogen from the hydrogen tank, in particular by the fuel cell system, and / or at least one other, further consumption. If, for example, no refueling process is planned or known, a possible refueling process can be assumed if the amount of hydrogen taken into the hydrogen tank, also referred to as the fill level, falls below a particularly predeterminable or predetermined threshold.and the previously described function for buffering waste heat from the cooling device in the hydrogen tank can be throttled, i.e. reduced or completely prevented, i.e. deactivated.

[0019] Further advantages, features, and details of the invention will become apparent from the following description of a preferred embodiment and from the drawings. The features and combinations of features mentioned above in the description, as well as the 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 respective combinations specified, but also in other combinations or on their own, without departing from the scope of the invention.

[0020] Further advantages, features, and details of the invention will become apparent from the following description of a preferred embodiment and from the drawings. The features and combinations of features mentioned above in the description, as well as the 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 respective combinations specified, but also in other combinations or on their own, without departing from the scope of the invention.

[0021] The drawing shows:

[0022] Fig. 1 is a schematic representation of a fuel cell system of a motor vehicle preferably designed as a commercial vehicle, in particular as a truck;

[0023] Fig. 2 is a flow chart illustrating a method for operating the fuel cell system of the motor vehicle schematically shown in Fig. 2; and Fig. 3 is a partial schematic sectional view of a

[0024] Hydrogen tank system of the fuel cell system

[0025] In the figures, identical or functionally identical elements are provided with the same reference symbols.

[0026] Fig. 1 shows a schematic representation of a fuel cell system 10 of a motor vehicle 12, schematically illustrated in Fig. 2, which is designed as a commercial vehicle, in particular as a truck. A method for operating the fuel cell system 10 is described below with reference to Figs. 1 to 3, wherein the method enables particularly efficient, in particular energy-efficient, operation of the fuel cell system 10 and thus of the motor vehicle 12 as a whole.

[0027] From Fig. 1 it can be seen that the fuel cell system 10 has at least one hydrogen tank 14, which is shown particularly schematically in Fig. 1 and simply referred to as a tank, in which hydrogen can be accommodated or is accommodated. In conjunction with Fig. 3 it can be seen that the hydrogen tank 14 is part of a tank system 16, also referred to as a tank device, which is explained in more detail below. The hydrogen is accommodated in the hydrogen tank 14 under pressure, so that a pressure, also referred to as tank pressure, prevails in the hydrogen tank 14 and is caused by the hydrogen accommodated in the hydrogen tank 14, which pressure is, for example, in a range from 6 bar up to and including 15 bar, and should in particular be. In particular, a liquid phase and a gaseous phase of the hydrogen are accommodated in the hydrogen tank 14.The fuel cell system 10 further comprises at least one fuel cell 18, which, as illustrated in Fig. 1 by an arrow 20, can be supplied with hydrogen from the hydrogen tank 14. For this purpose, for example, the hydrogen is removed from the hydrogen tank 14 and supplied, in particular in the gaseous state, to the fuel cell 18. The fuel cell 18 can be understood, for example, as a fuel cell stack, or the fuel cell 18 is a component of a fuel cell stack, which can have multiple fuel cells 18. Arrows 22 and 24 simply illustrate waste heat, also referred to as heat, which is released or provided by the fuel cell 18, for example, during its operation.An arrow 26 illustrates waste heat, also simply referred to as heat, which can be emitted, i.e. made available, by at least one sustained brake 28 of the motor vehicle 12, in particular during operation of the sustained brake 28. By means of the sustained brake, designed for example as a retarder, the motor vehicle 12 can be braked, in particular in such a way that a speed at which the motor vehicle 12 is driven along a roadway does not increase or is reduced. For example, the waste heat of the fuel cell 18 and the waste heat of the sustained brake 28 form a total waste heat. The arrow 22 illustrates, for example, that a first part of the total waste heat is fed to a device shown in Fig.1 and also referred to as a cooling system, in particular in such a way that the first part of the total waste heat is transferred, for example via a heat exchanger, to a particularly liquid coolant of the cooling device 30. Thus, the fuel cell 18 and preferably also the retarder 28 are cooled by means of the cooling device 30. The arrow 24 illustrates that a second part of the total waste heat can be transferred to or onto the hydrogen tank 14 and thus to or onto the hydrogen stored in the hydrogen tank 14, in particular via a heating device 32 of the fuel cell system 10, which is shown particularly schematically in FIG. 1 and is simply also referred to as a heater, so that the second part of the total waste heat is kept away from the cooling device 30 and is therefore not dissipated by the cooling device 30.This advantageously minimizes the thermal load on the cooling device 30. The cooling device 30 has, for example, a refrigerant circuit through which the coolant can flow. For example, the cooling device 30 comprises a fan, which is particularly electrically operated, by means of which air can be conveyed. The air can, for example, flow around a radiator through which the coolant can flow. The coolant can be cooled as a result of heat transfer from the coolant via the radiator to the air flowing around the radiator and conveyed by the fan.Since, as illustrated by the arrows 22 and 24, not all of the waste heat is dissipated to and through the cooling device 30, but the second part of the total waste heat is transferred to or to the hydrogen tank 14 and thus buffered, for example, by means of the hydrogen tank 14, an excessively long operating time of the fan during a total period of time can advantageously be kept low, so that a particularly efficient, in particular energy-efficient, operation of the cooling device 30 and thus of the fuel cell system 10 as a whole can be realized.

[0028] By transferring the heat, i.e., the second part of the total waste heat, to the hydrogen tank 14, as illustrated in Fig. 1 by an arrow 34, evaporation of liquid hydrogen stored in the hydrogen tank 14, i.e., at least a portion of the liquid phase of the hydrogen in the hydrogen tank 14, is brought about, thereby increasing the tank pressure. As will be explained in more detail below, the hydrogen tank 14, in particular the tank system 16, is used to relieve the cooling device 30 during high-load phases with high energy consumption by buffering waste heat, i.e., the second part of the total waste heat in the hydrogen tank 14, thereby saving energy, in particular electrical energy. For this purpose, as will be explained in more detail below, an energy consumption of the cooling device 30 is predicted as a function of a planned and, for example, predicted route of the motor vehicle 12.Furthermore, a future, temporal pressure profile of the pressure prevailing in the hydrogen tank 14, i.e., the tank pressure, is predicted. For example, the energy consumption and the pressure profile, which is also referred to as the pressure trajectory, are predicted, i.e., determined in advance, by means of an electronic computing device, in particular of the motor vehicle 12. Furthermore, a future, temporal energy profile, also referred to as an energy trajectory or heating energy trajectory, of a heating energy quantity is predicted, in particular by means of the electronic computing device, which is to be supplied, i.e., should be supplied, according to the energy profile, from the cooling device 30 and thus, for example, via the cooling device 30 to the hydrogen tank 14 depending on the predicted energy consumption in order to realize the pressure profile.The amount of heating energy is thus heat, i.e. thermal energy or a thermal energy quantity, which is illustrated, for example, in Fig. 1 by the arrow 24. In other words, the arrow 24 illustrates, for example, the amount of heating energy, which is the second part of the total waste heat and is to be supplied or is supplied to the hydrogen tank 14 according to the predicted energy curve from the cooling device 30, for example via the coolant or by means of the coolant, depending on the predicted energy consumption, in order to thereby realize the pressure curve, in particular while the motor vehicle 12 is traveling along the planned route, in particular actually traveling. A planning module, also referred to as logistics planning or designed to carry out logistics planning, is shown particularly schematically in Fig. 2 and is designated by 34.For example, the planning module 34 is used to plan the driving route, which is also referred to as a tour, i.e. to plan in advance. For example, the planning module 34 is used to determine, in particular to specify, when, i.e. at what time or during what period of time, the motor vehicle 12 will drive which driving route, also referred to as a route, where, i.e. at what point along the driving route, refueling will take place, i.e. when, i.e. at what point in time, the journey of the motor vehicle 12 along the driving route will be interrupted or where downtimes are planned, i.e. to take place. The refueling process, which is also referred to as the refueling process, is to be understood as a process by which or during which hydrogen is poured into the hydrogen tank 14, in particular from outside the hydrogen tank 14, in particular from outside the motor vehicle 12 as a whole.The respective downtime is a period of time or a time interval during which the motor vehicle 12 is stationary and thus not powered by the fuel cell system 10, so that, for example, during the respective downtime, hydrogen is not discharged from the hydrogen tank 14, in particular to the fuel cell 18. When planning the route, for example, further parameters are taken into account which characterize the route or the motor vehicle 12 along the route. The parameters can include, for example, a load of the motor vehicle 12 and / or a planned operation of each consumption of a motor vehicle 12, which can be, for example, a cooling structure for cooling a cargo space of the motor vehicle 12.

[0029] An arrow 36 illustrates that relevant, in particular all relevant, tour planning data characterizing the planned route are transmitted to and received by an operating strategy module 38. The operating strategy module 38 determines, in particular calculates, for example, an operating strategy, in particular the entire operating strategy, for the planned route, also referred to as a tour. For example, the operating strategy is a predictively determined, and therefore planned, operating strategy according to which the fuel cell system 10 is to be or is to be operated, in particular when the motor vehicle 12 is actually traveling along the route.This includes, for example, a torque to be provided by a drive device in order to drive the motor vehicle 12 and thus to travel along the travel route, also referred to as the route, so that the motor vehicle 12 can manage the travel route, a target trajectory derived therefrom for a power of the fuel cell 18, also referred to as fuel cell power, and in particular, associated therewith, a charge state profile of a buffer battery of the motor vehicle 12. The drive device comprises, for example, at least one electric machine, by means of which the motor vehicle 12 can be driven, in particular purely electrically, in order to thereby drive the motor vehicle 12 along the travel route.The buffer battery is a battery, in particular a secondary battery, in which electrical energy provided or that can be provided, for example, by the fuel cell 18 can be at least temporarily stored, i.e., buffered. For example, the drive device, in particular the electric machine, can be supplied with the electrical energy provided by the fuel cell 18 and / or with the electrical energy stored in the battery, so that the motor vehicle 12 can be electrically driven by the electric machine. The operating strategy also takes into account, for example, at least one or more continuous braking systems of the motor vehicle 12, such as the continuous braking system 28.In other words, the operating strategy also includes, for example, a strategy for operating the continuous brake 28 along the travel route, wherein the continuous brake 28, as described above, generates or can generate an additional heat input, in particular into the cooling device 30.

[0030] In addition, the pressure curve and the energy curve are predicted. The heating energy quantity is a target heating energy quantity that must be supplied to the hydrogen tank 14, in particular while the motor vehicle 12 is traveling along the route, in order to effect, i.e., realize, the pressure curve. By predicting the energy consumption of the cooling device 30, operating phases, also referred to as phases, can be easily determined during which, while the motor vehicle 12 is traveling along the route, energy can be dissipated in the hydrogen tank 14, thus the heating energy quantity can be supplied to the hydrogen tank 14. In particular, downtimes can be predicted, if necessary, if driving times, travel times, and habits regarding usual operating and downtimes are evaluated.

[0031] The determined, in particular calculated, operating strategy is transmitted, as illustrated by an arrow 40, in particular from the operating strategy module 38 to a thermal management module 42 and received by the thermal management module 42. For example, the operating strategy module 38 and / or the thermal management module 42 is a component of the aforementioned electronic computing device.

[0032] The pressure trajectory and the heating energy trajectory are also simply referred to as trajectories and are target trajectories. The thermal management module 42 is designed to implement, i.e., realize, the previously strategically determined, in particular calculated, target trajectories, thus operating, in particular controlling or regulating, the fuel cell system 10 in such a way that the target trajectories are implemented, i.e., that the fuel cell system 10 operates or is operated according to the predicted target trajectories. This is achieved, for example, by the thermal management module 42, as illustrated by an arrow 44, controlling an actuator 46, also referred to as an actuator or thermal system actuator, in particular of the fuel cell system 10. The actuator 46 comprises, for example, valves, pumps, and at least one or more fans, such as the aforementioned fan.For example, a sensor system 48 is also provided, which is also referred to as a thermal system sensor system. As illustrated by an arrow 50, the sensor system 48 can detect measured variables, such as pressures and / or temperatures of the fuel cell system 10, and transmit them to the thermal management module 42, which can control, i.e. operate, in particular control or regulate, the fuel cell system 10, in particular the actuator system 46, depending on the measured variables detected by the sensor system 48, in particular in order to implement the target trajectories, thus operating the fuel cell system 10 according to the target trajectories. One of the measured variables is, for example, the aforementioned tank pressure. Another of the measured variables is, for example, other pressures of the fuel cell system 10. Furthermore, the measured variables can include at least one or more temperatures of the fuel cell system 10.The respective pressure is detected, for example, by a respective pressure sensor. The respective temperature is detected, for example, by a respective temperature sensor. For example, the thermal management module 42 is used to control the fuel cell system 10, in particular the actuators 46, to predetermined or predeterminable target values, in particular in such a way that the desired trajectories are actually implemented.If a predictively calculated target specification, such as the tank pressure and / or a coolant temperature, is not or cannot be reached, a new determination, in particular a recalculation, of the predictive operating strategy can be carried out, as illustrated by an arrow 52, ​​in particular by the operating strategy module 38, in particular on the basis of new status data which is detected, for example, by means of the sensor system 48 and thus determined by the thermal management module 42 and, in particular, is shown by the arrow 52, ​​transmitted to the operating strategy module 38 and received by it. This can be carried out cyclically, for example, in particular on the basis of current states and measured values ​​of the motor vehicle 12. For example, the coolant comprises at least water, so that the coolant is also referred to, for example, as cooling water.

[0033] As illustrated, for example, by an arrow 54, the thermal management module 42 can transmit at least one or more specifications for heating the hydrogen tank 14 to an operating module 56 for operating, in particular for regulating or controlling, the tank system 16, i.e., for supplying the amount of heating energy to the hydrogen tank 14 in accordance with the energy profile and thus warming it, i.e., heating it. For example, the operating module 56 is a component of the electronic computing device. The operating module 56 is referred to, for example, as a tank control module or tank regulation module. For example, as illustrated by the arrow 54, a need for heat removal from the hydrogen tank 14, in particular at a desired point in time or during a desired period of time, is transmitted from the thermal management module 42 to the operating module 56, and received in particular by the operating module 56.The operating module 56 implements the specifications provided by the thermal management module 42 and received by the operating module 56, in particular within the scope of possibilities and / or within the permitted pressure range, which corresponds, for example, to the aforementioned range of 6 to 15 bar, and reports this implementation back to the thermal management module 42, which is illustrated by an arrow 58. The feedback includes, for example, an estimated amount of heat dissipated from or by the hydrogen tank 14 based on the specification, as well as the tank pressure, in particular as the actual pressure, prevailing in the hydrogen tank 14 and caused in particular by the hydrogen absorbed in the hydrogen tank 14.A central, i.e., effective control or regulating element for regulating, i.e., adjusting a heat flow in the hydrogen tank 14, i.e., adjusting the amount of heating energy supplied to the hydrogen tank 14, is, for example, a valve 60, shown particularly schematically in Fig. 2 and designed, for example, as a pressure valve, in particular as a pressure control valve or pressure regulating valve, which can be controlled, for example, by the operating module 56 and thereby operated, in particular regulated or controlled. By means of the valve 60, for example, a flow of the, in particular, gaseous hydrogen is adjusted through a heat exchanger 62 shown in Fig. 3. The heat exchanger 62 is a component of the tank system 16 and will be explained in more detail below. If, for example, the valve 60 is fully opened, this enables maximum heat flow into the hydrogen tank 14.If the valve 60 is closed, the hydrogen tank 14 is, for example, no longer heated, which may be the case in particular at partial load, causing the tank pressure to drop (again), for example.

[0034] This method allows the energy consumption of the fuel cell system 10 to be reduced compared to conventional solutions, thereby keeping the energy consumption of the entire motor vehicle 12 particularly low. This allows the motor vehicle 12 to be operated particularly cost-effectively. Furthermore, overloading of the cooling device 30, with the associated shutdown of components such as the drive system, can be delayed or completely avoided.

[0035] The cooling device 30 has, for example, a cooling circuit 64 through which the coolant can flow, and of which line elements 66 and 68 are shown in detail in Fig. 3. The coolant can flow through the line elements 66 and 68. The coolant, which in particular contains heat such as the second part of the total waste heat, can be supplied to the heat exchanger 62 by means of the line element 66. For example, a flow of the coolant through the line element 66 and in particular towards the heat exchanger 62 can be adjusted by means of a valve 70 arranged in the line element 66. The valve 70 can be controlled by the thermal management module 42, so that the thermal management module 42 can adjust, in particular control or regulate, the flow of the coolant through the line element 66 towards the heat exchanger 62 via the valve 70. The coolant can be discharged from the heat exchanger 62 via the line element 68.

[0036] The hydrogen tank 14 can be vented via a vent line 72, and the hydrogen tank 14 can be refueled via a tank device 74. Vent lines are designated by 76, a valve designed, for example, as a tank valve is designated by 78, and a valve designed, for example, as a safety valve is designated by 80. For example, the hydrogen can be discharged from the hydrogen tank 14 via a line element 82 and, in particular, supplied to the fuel cell 18. It can be seen that the operating module 56 can, for example, control and thereby operate the valve 78 and the valve 60, and for example, the operating module 56 can control and thereby operate the heat exchanger 62. The aforementioned temperature sensors are designated by 84 in Fig. 3, and the aforementioned pressure sensors are designated by 86.By means of a detection 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 fill level. The detection device 88 can provide at least one signal characterizing the fill level, in particular an electrical signal, which can be received by the operating module 56.The operating module 56 can report the recorded temperatures, the recorded pressures and the recorded fill level back to the operating strategy module 38, which can then create the specifications and specify them to the operating module 56, so that, for example, the tank system 16 can be operated, in particular controlled or regulated, by means of the thermal management module 42 and by means of the operating module 56, in particular as a function of the recorded temperatures and as a function of the recorded pressures and as a function of the recorded fill level, in particular in such a way that the target trajectories are actually implemented, i.e. realized.

[0037] From Fig. 3 it can be seen that the heat contained in the coolant and thus the aforementioned second part of the total waste heat can be transferred to the hydrogen tank 14, in particular to the hydrogen in the hydrogen tank 14, via the heat exchanger 62, in order to warm, and thus heat, the hydrogen tank 14 and thus the hydrogen contained in the hydrogen tank 14. As a result, the hydrogen tank 14 can be used at least temporarily as a heat buffer, whereby the energy consumption of the cooling device 30 can advantageously be kept low. Furthermore, for example, via the heat exchanger 62, the heat contained in the coolant, thus the second part of the total heat, can be transferred to the hydrogen flowing through the line element 82, in particular in the gaseous state, which hydrogen is discharged from the hydrogen tank 14, for example, by means of the line element 82 and fed to the fuel cell 18.As a result, the hydrogen, in particular gaseous, which is supplied to the fuel cell 18, 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 dissipated, in particular without operating the aforementioned fan. List of reference symbols.

[0038] 10 Fuel cell system

[0039] 12 Motor vehicle

[0040] 14 Hydrogen tank

[0041] 16 Tank system

[0042] 18 fuel cell

[0043] 20 Arrow

[0044] 22 Arrow

[0045] 24 Arrow

[0046] 26 Arrow

[0047] 28 Continuous brake

[0048] 30 Cooling device

[0049] 32 Heating device

[0050] 34 Arrow

[0051] 35 Planning module

[0052] 36 Arrow

[0053] 38 Operating strategy module

[0054] 40 Arrow

[0055] 42 Thermal management module

[0056] 44 Arrow

[0057] 46 Actuators

[0058] 48 Sensor technology

[0059] 50 arrows

[0060] 52 Arrow

[0061] 54 Arrow

[0062] 56 Operating module

[0063] 58 Arrow

[0064] 60 valve

[0065] 62 heat exchangers

[0066] 64 Cooling circuit

[0067] 66 line element

[0068] 68 line element

[0069] 70 valve

[0070] 72 vent line

[0071] 74 Tank equipment

[0072] 76 Blow-off line Valve Valve Line element Temperature sensor Pressure sensor Detection device

Claims

Daimler Truck AG Dr. Riege May 9, 2023 Patent claims 1. Method for operating a fuel cell system (10) of a motor vehicle (12), the fuel cell system (10) of which has at least one hydrogen tank (14), at least one fuel cell (18) that 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: - the energy consumption of the cooling device (30) is predicted depending on a planned route of the motor vehicle (12), - a future pressure profile over time of a pressure prevailing in the hydrogen tank (14) is predicted, and - a future, temporal energy profile of a quantity of heating energy is predicted, which according to the energy profile is to be supplied from the cooling device (30) to the hydrogen tank (14) depending on the predicted energy consumption in order to realize the pressure profile.

2. Method according to claim 1, characterized in that the pressure profile and the energy profile are predicted such that in first operating phases of the cooling device (30), in the first operating phases of which the energy consumption is greater than in second operating phases of the cooling device (30), a greater heat energy is supplied to the hydrogen tank (14) by the cooling device (30) than in the second operating phases. A method according to claim 2, characterized in that in at least one of the second operating phases, a transfer of heat energy from the cooling device (30) to the hydrogen tank (14) is prevented. A method according to any of the preceding claims, characterized in that the pressure profile is predicted such that the pressure is always less than or equal to a maximum pressure throughout its entire pressure profile. A method according to any of the preceding claims, characterized in that at least the pressure profile is predicted as a function of at least one refueling operation provided for filling the hydrogen tank (14) and / or as a function of at least one idle period of the motor vehicle (12). A motor vehicle (12) configured to carry out a method according to any of the preceding claims.

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