Hydrogen tank system

Abstract

The present invention relates to a hydrogen tank system (1), in particular for a fuel cell system (100) of an aircraft propulsion system (109), the hydrogen tank system comprising: a main tank (10) for storing liquid hydrogen (2.1) and for providing gaseous hydrogen (2.2); a storage tank (20) for storing liquid hydrogen (2.1); and a pressure-increasing device (40); wherein the pressure-increasing device (40) is designed to force liquid hydrogen (2.1) via a feed line (30) into the main tank (10) by increasing a gas pressure p20, p30.

Description

[0001] HYDROGEN TANK SYSTEM

[0002] DESCRIPTION

[0003] Technical area

[0004] The present invention relates to a hydrogen tank system, in particular for a fuel cell aircraft propulsion system.

[0005] State of the art

[0006] Compared to conventional fuels, such as kerosene, hydrogen can pose special requirements, for example, regarding storage in a tank or tank system. Hydrogen can be carried in liquid form as cryogenic hydrogen, i.e., as so-called liquid hydrogen. However, for use in a propulsion system, such as a fuel cell, it typically has to be available in gaseous form, i.e., supplied to the propulsion system in gaseous form.

[0007] Description of the invention

[0008] The present invention is based on the technical problem of providing an advantageous hydrogen tank system.

[0009] This is achieved according to the invention with the tank system according to claim 1. This firstly has a main tank from which the drive or the fuel cell system can be supplied with gaseous hydrogen. It also has a storage tank in which liquid hydrogen is stored during operation. Furthermore, a pressure increasing device and a supply line are provided, the latter opening into the main tank. The pressure increasing device can be used to increase a gas pressure, e.g. in the storage tank itself or in an additional pump tank (see below in detail), whereby by increasing the gas pressure, liquid hydrogen can be forced into the main tank via the supply line. The division into main and storage tanks can be advantageous, for example, in that the tanks can be optimized for their respective application. In the case of the main tank, which provides the gaseous hydrogen during operation (and e.g.In a lower section (liquid hydrogen is stored in a lower section), this can mean, for example, a design for permanently higher tank pressures, for example in the range of 4 bar to 8 bar. In the storage tank, however, in which the liquid hydrogen is kept cold for as long as possible, the tank pressures can be lower due to the lower evaporation pressure, for example in a range between 1 bar and 3 bar. Due to the lower structural load, the design requirements can therefore be lower, which can result in economic but especially weight advantages.

[0010] Independently of this, the solution also offers modularity. For example, depending on the application, such as the planned flight duration, a main tank can be equipped with one or more storage tanks of different sizes. Multiple, individually smaller tanks can also be more easily accommodated, thus simplifying integration into, for example, an aircraft, especially with regard to round / cylindrical tank geometries. The gas pressure-driven redistribution of liquid hydrogen is comparatively easy to implement, also with regard to the modular connectivity of different tanks, and is also robust, for example, compared to a pump with mechanically moving parts.

[0011] Preferred embodiments can be found throughout the disclosure and in particular in the dependent claims, although the presentation of the features does not always distinguish in detail between the different claim categories; at least implicitly, the disclosure always focuses equally on aspects of the device and method or use. For example, if a tank system suitable for a specific operation is described, this is to be understood simultaneously as a disclosure of a corresponding operating method.

[0012] In general, "a" and "an" are to be read as indefinite articles in this disclosure and thus, unless expressly stated otherwise, always as "at least one" or "at least one." For example, there may be multiple storage tanks and / or multiple supply lines. With regard to the propulsion system as a whole or the aircraft, there may also be multiple main tanks, for example, to create redundancy.

[0013] The main and storage tanks may differ, for example, in that the main tank is designed for a higher operating pressure. Alternatively or additionally, a difference may also be that the storage tank has a larger internal volume, e.g., at least 1.5, 2, 2.5, or 3 times larger (upper limits may ultimately depend on the propulsion system or aircraft as a whole; exemplary values ​​could be 100, 50, or 10 times larger, respectively). Regardless of these possible differences from the storage tank, the main tank may, for example, be equipped with an evaporator to provide gaseous hydrogen.

[0014] According to a preferred embodiment, the pressure boosting device, which can be used to increase the gas pressure for injecting liquid hydrogen into the main tank, is a heater. This heater can be used to heat the liquid hydrogen in the corresponding tank, i.e., the storage or pump tank (see below), and thus increase the gas pressure in this tank. For this purpose, it is arranged, for example, in a lower section of the tank.

[0015] In a preferred embodiment, the supply line is equipped with an adjustment element with which a flow through the supply line can be adjusted. The latter can generally only comprise two states, closed and open, but alternatively, for example, the flow rate can also be adjusted. In general, for example, a butterfly valve or a gate valve is also possible, although the supply line adjustment element is preferably a valve. Generally, electronic control is preferred, so a respective adjustment state can be specified for the supply line adjustment element, for example by a control unit. A control unit can also be part of the tank system, independent of the supply line adjustment element, for example for controlling the pressure boosting device. The control unit can, for example, be provided locally, for example microcontroller-based, or globally, for example as a functional subunit of an on-board computer.Independently of these details, commands can be stored in the control unit which cause it to control the tank system in such a way that it is operated in a manner disclosed herein.

[0016] According to a preferred embodiment, a pump tank is provided in addition to the storage tank, wherein the pressure increasing device, in particular heating, is arranged in the pump tank. The pump tank can, for example, create a certain decoupling in that only a portion of the hydrogen needs to be heated to increase the pressure. The pump tank can preferably have a smaller internal volume than the storage tank and / or the main tank. As will be made clear in detail below, the liquid hydrogen can, on the one hand, be forced from the pump tank into the main tank, but, on the other hand, the pressure in the storage tank can also be increased by increasing the pressure in the pump tank and the liquid hydrogen can be supplied from there.

[0017] In a preferred embodiment, a lower section of the pump tank is fluidically connected to a lower section of the storage tank. To the extent that reference is generally made within the scope of this disclosure to a "lower section" of a tank, this can, for example, range from 0% to 50%, based on a vertical extent of the internal volume of the corresponding tank, which ranges from 0% at the bottom to 100% at the top. An "upper section," on the other hand, can range from 50% to 100%. In detail, an arrangement "in a lower section" can then mean, for example, between 0% and 30%, in particular between 0% and 20%. Furthermore, an arrangement "in an upper section" can then mean, for example, between 70% and 100%, in particular between 80% and 100%.

[0018] During operation, this connection between the storage and pump tanks, also referred to below as the liquid storage / pump tank line, can be used, for example, to fill the pump tank with liquid hydrogen from the storage tank. This line is preferably equipped with an adjustment element (see the above disclosure for further details), in particular with an electronically controllable valve.

[0019] In a preferred embodiment, a pump tank connection point of the liquid storage / pump tank line is located at a lower geodetic elevation than its storage tank connection point. This allows the liquid hydrogen to flow from the storage tank to the pump tank by gravity when the adjustment element of the liquid storage / pump tank line is opened.

[0020] According to a preferred embodiment, an upper section of the pump tank and an upper section of the storage tank are fluidically connected to one another. Gaseous hydrogen can be exchanged between the pump tank and the storage tank during operation via this gas storage / pump tank line, for example, for pressure equalization during gravity-driven filling of the pump tank from the storage tank or for pressurizing the storage tank when filling the main tank from the storage tank. The gas storage / pump tank line is preferably equipped with an adjusting element for adjusting a flow rate (see the above disclosure for further details), in particular with an electronically controllable valve.

[0021] According to a preferred embodiment, the supply line through which the liquid hydrogen is supplied to the main tank is fluidically connected to the storage tank. In other words, the liquid hydrogen is supplied to the main tank directly from the storage tank. Another possibility for this, "pressure boosting device in the storage tank," is discussed below; first, the related use of the pump tank will be examined in more detail. If this is fluidically connected to the storage tank via the gas storage / pump tank line, increasing the pressure in the pump tank can also increase the pressure in the gas phase of the storage tank (with the adjustment element open), so that liquid hydrogen can be forced into the main tank via the supply line (with the supply line adjustment element open, if present). One advantage of this variant can be, for example, that the pressure is generated without heating the hydrogen in the storage tank.The pump tank used to generate pressure can be filled via a liquid storage / pump tank line discussed above, but in a preferred embodiment, filling can also take place from the main tank. For this purpose, a lower section of the main tank can be fluidically connected to the pump tank, in particular a lower section thereof, namely via a liquid pump / main tank line. This is preferably equipped with an adjusting element for adjusting a flow rate, see above for possible details, in particular with an electronically controllable valve. Optionally, a gas pump / main tank line can also be provided, which connects the upper sections of the pump and main tank and can, for example, create pressure equalization.This is also preferably equipped with an adjustment element for adjusting a flow rate, see above for further details, in particular an electrically controlled valve.

[0022] When filling the pump tank, these two adjustment elements can be open, while the supply line adjustment element is closed. After filling the pump tank, the adjustment elements of the pump / main tank lines are closed, and the pressure in the pump tank is increased using the pressure booster (e.g., until it exceeds the pressure in the main tank). The supply line adjustment element can then be opened, allowing the liquid hydrogen to be forced from the storage tank into the main tank due to the pressure increase in the storage tank mediated by the gas storage / pump tank line.

[0023] According to an alternatively preferred embodiment, the supply line leading into the main tank is connected to a lower section of the pump tank. As the gas pressure in the pump tank increases, the liquid hydrogen is forced from the pump tank into the main tank when the supply line adjustment element is opened. The pump tank is filled from the storage tank, preferably via the liquid storage / pump tank line equipped with an adjustment element. Further preferably, a gas storage / pump tank line equipped with an adjustment element is also provided, wherein both adjustment elements are open to fill the pump tank and subsequently closed to increase the pressure in the pump tank and fill the main tank.

[0024] According to an alternatively preferred embodiment, the pressure-increasing device is arranged in the storage tank itself; in other words, the pumping function is realized within the storage tank. The supply line connects a lower section of the storage tank to the main tank. To fill the main tank, the pressure in the storage tank is preferably first increased (until it is greater than the pressure in the main tank). Then, the adjusting element is opened, forcing liquid hydrogen into the main tank.

[0025] In a preferred embodiment, the pressure boosting device provided as a heater is located in the storage tank, but in a separate compartment. A portion of the internal volume of the storage tank is thus partially separated, so that although there is a fluidic connection with the remaining internal volume, the heater arranged in the compartment is partially thermally insulated. This creates a certain thermal decoupling. The compartment is preferably in fluidic connection with both an upper section and a lower section of the remaining internal volume, i.e. with both the liquid and the gas phase. Liquid hydrogen can flow in at the bottom and then be heated by the heater, with the gas escaping at the top, allowing the pressure increase to be passed on to the entire internal volume.

[0026] The invention also relates to a storage tank with an integrated pressure boosting device and / or a pump tank with an integrated pressure boosting device.

[0027] The invention also relates to a fuel cell system, in particular a fuel cell aircraft propulsion system, with a hydrogen tank system as disclosed herein. The fuel cell system can additionally have fuel cells, which can typically be provided in the form of one or more stacks. The gaseous hydrogen from the main tank is supplied to the fuel cells as a reaction gas; oxygen or air can serve as a further reaction gas. The fuel cells can then, for example, supply an electric motor with electrical power. The invention further relates to an aircraft, in particular an airplane, with such a fuel cell system or propulsion system. The fuel cell system is installed with the hydrogen tank system in the aircraft, in particular an airplane. In other words, the tanks of the hydrogen tank system, e.g.the main tank and the storage tank, and if present also the pump tank, are structurally integrated into or on the aircraft, e.g. integrated into the fuselage and / or wing. In particular, if multiple storage tanks are provided (see details above), one or more of them can also be attached to the outside of the aircraft as an additional tank, e.g. below the wing. Irrespective of such details, the hydrogen tank system is integrated into the aircraft in such a way that it, including the tank system, can be used as intended, i.e. for aviation / flight operations. Accordingly, for example, during operation, i.e. during flight, gaseous hydrogen is made available from the main tank and, conversely, the main tank is filled with liquid hydrogen, depending on the design, from the storage or pump tank - see details above.

[0028] Furthermore, the invention relates to a method for operating a tank or fuel cell system or corresponding aircraft, wherein liquid hydrogen is stored in the storage tank. The pressure booster device increases the gas pressure, either in the storage tank itself or in a pump tank, in order to force liquid hydrogen into the main tank, for example, after opening the supply line adjustment element.

[0029] Furthermore, the invention relates to the use of a main tank and / or a storage tank and / or a pressure increasing device in a hydrogen tank system disclosed herein.

[0030] Short description of the drawings

[0031] In the following, the invention is explained in more detail using exemplary embodiments, whereby the individual features within the scope of the independent claims can also be essential to the invention in other combinations and no distinction is made in detail between the different claim categories.

[0032] In detail,

[0033] Figure 1 shows a first hydrogen tank system in a schematic representation;

[0034] Figure 2 shows a schematic representation of a second hydrogen tank system; Figure 3 shows a schematic representation of a third hydrogen tank system; Figure 4 shows a schematic representation of a fourth hydrogen tank system;

[0035] Figure 5 shows a fifth hydrogen tank system in schematic representation;

[0036] Figure 6 shows a schematic representation of a sixth hydrogen tank system; Figure 7 shows a schematic representation of a fuel cell aircraft propulsion system; Figure 8 shows an aircraft with an aircraft propulsion system according to Figure 7.

[0037] Preferred embodiment of the invention

[0038] Figure 1 shows a hydrogen tank system 1 comprising a main tank 10 and a storage tank 20. Liquid hydrogen 2.1 is stored in the internal volume 21 of the storage tank 20, while gaseous hydrogen 2.2 is present in the upper area. This applies analogously to the main tank 10, from which the gaseous hydrogen 2.2 is then supplied as a reaction gas to a propulsion system, in particular a fuel cell aircraft propulsion system (see below) (indicated by a dashed arrow).

[0039] The main tank 10 is filled with liquid hydrogen 2.1 from the storage tank 20, for which purpose a supply line 30 connects a lower section 20.1 of the storage tank 20 to the main tank 10 (reference numeral 20.2 denotes an upper section). The supply line 30 is equipped with a supply line adjustment element 31, in this case an electronically controllable valve. A pressure-increasing device 40, provided in the form of a heater 41, is arranged in the storage tank 20. By heating the liquid hydrogen 2.1, the pressure in the gas phase, i.e., the gaseous hydrogen 2.2, can be increased. The supply line adjustment element 31 is initially closed. If the gas pressure P20 in the storage tank 20 is greater than the gas pressure pw in the main tank 10, the supply line adjustment element 31 can be opened and liquid hydrogen 2.1 can be pressed into the main tank 10 via the supply line 30.

[0040] Figure 2 shows a hydrogen tank system 1 comparable in principle to that shown in Figure 1. In general, throughout this disclosure, identical reference numerals designate identical parts or parts with comparable functions, and reference is always made to the description of the other figures. Therefore, the differences are emphasized primarily below.

[0041] In the hydrogen tank system 1 according to Figure 2, the heater 41 is arranged in the storage tank 20 in a separate compartment 25. In this case, this compartment is designed as a tubular, for example, essentially hollow-cylindrical body, which is open at the upper end and provided with inlet openings at the lower end. Liquid hydrogen 2.1 can flow in through the latter, and gaseous hydrogen 2.2 can exit at the upper end. The compartment 25 provides a certain degree of thermal insulation from the remaining internal volume 21 or liquid hydrogen 2.1, so the heater 41 at least does not directly affect the entire liquid hydrogen 2.1.

[0042] Figure 3 shows a hydrogen tank system 1 which, in addition to the main tank 10 and storage tank 20, has a pump tank 50 in which the pressure booster device 40 is arranged. As in the case of Figures 1 and 2, the illustration is not to scale; in particular, the storage tank 20 is in reality not only larger than the pump tank 50, but also larger than the main tank 10. The supply line 30 connects a lower section 50.1 of the pump tank 50 to the main tank 10. The liquid hydrogen 2.1 is thus forced from the pump tank 50 into the main tank 10 by increasing the gas pressure pso by means of the pressure booster device 40 (with the supply line adjustment element 31 open).

[0043] The adjustment elements 61, 71 are closed. The adjustment element 61 is assigned to a liquid storage / pump tank line 60, which connects the lower section 20.1 of the storage tank 20 with the lower section 50.1 of the pump tank 50. The adjustment element 71 is assigned to a gas storage / pump tank line 70, which connects the upper sections 20.2, 50.2. To fill the pump tank 50, with the supply line adjustment element 31 closed, both adjustment elements 61, 71 are opened so that liquid hydrogen 2.1 flows from the storage tank 20 into the pump tank 50. Unlike the filling of the main tank 10, this is gravity-driven; the pump tank connection point 62 is located at a lower geodetic height than the storage tank connection point 63.

[0044] Figure 4 shows a hydrogen tank system 1 comparable to that shown in Figure 3. In contrast, however, several storage tanks with corresponding fluidic connections are provided, namely a first storage tank 20a and a second storage tank 20b. These are connected to the pump tank 50 via a respective line system, i.e. via a first liquid storage / pump tank line 60a and a first gas storage / pump tank line 70a in the case of the first storage tank 20a, and via a second liquid storage / pump tank line 60b and a second gas storage / pump tank line 70b in the case of the second storage tank 20b. The filling of the main tank 10 takes place analogously to Figure 4 with the setting elements 61a, b, 71a, b closed. The pump tank 50 can be filled either from the first or the second storage tank 20a, b, i.e. either by opening the adjusting elements 61a, 71b or the adjusting elements 61b and 71b.

[0045] Figure 5 shows a hydrogen tank system 1 in which the pressure booster 40 is also arranged in a pump tank 50. By increasing the gas pressure (pst) in the pump tank 50, however, in this case the liquid hydrogen 2.1 is not forced from the pump tank 50, but from the storage tank 20 into the main tank 10. The supply line 30 connects the lower section 20.1 of the storage tank 20 to the main tank 10. Furthermore, the gas storage / pump tank line connects the upper section 20.2 of the storage tank 20 to the upper section 50.2 of the pump tank 50, so that by increasing the gas pressure (pso), the gas pressure (P20) in the storage tank 20 is also increased. The supply line adjustment element 31 and the adjustment element 61 are initially closed, and as soon as the gas pressure P20 is greater than the gas pressure pw, the liquid hydrogen 2.1 can be pressed into the main tank 10 by opening the supply line adjustment element 31.To fill the pump tank 50, the supply line adjustment element 31 is closed and the adjustment element 61 is opened so that the liquid hydrogen 2.1 can flow into the pump tank 50 by gravity.

[0046] The hydrogen tank system 1 according to Figure 6 is similar in its basic structure to that according to Figure 5. The main tank 10 is therefore pressed in from the storage tank 20 as a result of an increase in the gas pressure pso and thus the gas pressure P20 via the supply line 30. One difference, however, is the filling of the pump tank 50 with liquid hydrogen 2.1, which, according to Figure 6, takes place from the main tank 10. For this purpose, the lower section 50.1 of the pump tank 50 is connected to the main tank 10 via a liquid pump / main tank line 80, and the adjusting element 81 can be opened for filling. Furthermore, the upper section 50.2 of the pump tank 50 is connected to the upper section 10.2 of the main tank 10 via a gas pump / main tank line 90 for pressure equalization. The adjusting element 91 is optional. For filling, the adjusting element 81 and, if present, also the adjusting element 91 are opened, while the supply line adjusting element 31 is closed. Then thethe adjusting elements 81, 91 between pump tank 50 and main tank 10 are closed, after which the pressure increase and consequently main tank filling can take place as described for Figure 5.

[0047] Figure 7 shows a fuel cell system 100 comprising a plurality of fuel cells 105 in the form of fuel cell stacks 106 and a hydrogen tank system 1. The latter supplies the fuel cells 105 with gaseous hydrogen 2.2, and the fuel cells 105 provide electrical power P to an electric motor 107, which is used to drive a propeller 108 and thus to generate thrust for the fuel cell aircraft propulsion system 109.

[0048] Figure 8 shows an aircraft 110, in this case an airplane 111, equipped with such an aircraft propulsion system 109. LIST OF REFERENCE SYMBOLS

[0049] Hydrogen tank system 1 liquid hydrogen 2.1 gaseous hydrogen 2.2

[0050] Main tank 10

[0051] Storage tank 20 lower section 20.1 upper section 20.2 first storage tank 20a second storage tank 20b

[0052] Internal volume 21

[0053] Compartment 25

[0054] Supply line 30

[0055] Supply line adjustment element 31

[0056] Pressure booster device 40

[0057] Heating 41

[0058] Pump tank 50 lower section 50.1 upper section 50.2

[0059] Liquid storage / pump tank line 60 first liquid storage / pump tank line 60a second liquid storage / pump tank line 60b

[0060] Adjustment element 61

[0061] Pump tank connection point 62

[0062] Storage tank connection point 63

[0063] Gas storage / pump tank line 70 first gas storage / pump tank line 70a second gas storage / pump tank line 70b

[0064] Adjustment element 71

[0065] Liquid pump / main tank line 80

[0066] Adjustment element 81 Gas pump / main tank line 90

[0067] Adjustment element 91

[0068] Fuel cell system 100

[0069] Fuel cells 105 Fuel cell stacks 106

[0070] Electric motor 107

[0071] Propellers 108

[0072] Fuel cell aircraft propulsion 109

[0073] Aircraft 110 electrical power P

[0074] Gas pressure in the main tank pio

[0075] Gas pressure in storage tank P20

[0076] Gas pressure in the pump tank pso

Claims

CLAIMS 1. Hydrogen tank system (1), in particular for a fuel cell system (100) of an aircraft propulsion system (109), with a main tank (10) for storing liquid hydrogen (2.1) and for making gaseous hydrogen (2.2) available, a storage tank (20) for storing liquid hydrogen (2.1), and a pressure increasing device (40), wherein the pressure increasing device (40) is configured to press liquid hydrogen (2.1) into the main tank (10) via a supply line (30) by increasing a gas pressure P20, pso.

2. Hydrogen tank system (1) according to claim 1, wherein the pressure increasing device (40) comprises a heater (41) for heating liquid hydrogen (2.1) and consequently increasing the gas pressure P20, pso.

3. Hydrogen tank system (1) according to claim 1 or 2, wherein the supply line (30) is equipped with a supply line adjusting element (31) for adjusting a flow rate.

4. Hydrogen tank system (1) according to one of the preceding claims, which additionally comprises a pump tank (50), wherein the pressure increasing device (40) for increasing the gas pressure pso is arranged in the pump tank (50).

5. Hydrogen tank system (1) according to claim 4, wherein a lower portion (50.1) of the pump tank (50) is fluidly connected to a lower portion (20.1) of the storage tank (20).

6. Hydrogen tank system (1) according to claim 5, wherein a pump tank connection point (62) of the fluidic connection is located at a lower geodetic height than a storage tank connection point (63).

7. Hydrogen tank system (1) according to one of claims 4 to 6, wherein an upper portion (50.2) of the pump tank (50) is fluidly connected to an upper portion (20.2) of the storage tank (20).

8. Hydrogen tank system (1) according to claim 7, wherein the supply line (30) which opens into the main tank (10) is fluidically connected to a lower section (20.1) of the storage tank (20) in such a way that by increasing a gas pressure pso in the pump tank (50) and thus increasing a gas pressure P20 in the storage tank (20), liquid hydrogen (2.1) can be forced from the storage tank (20) via the supply line (30) into the main tank (10).

9. Hydrogen tank system (1) according to claim 8, wherein a lower portion (50.1) of the pump tank (50) is fluidly connected to a lower portion (10.1) of the main tank (10) for filling the pump tank (50) from the main tank (10).

10. Hydrogen tank system (1) according to one of claims 4 to 7, in which the supply line (30) which opens into the main tank (10) is fluidically connected to a lower section (50.1) of the pump tank (50) in such a way that by increasing a gas pressure pso in the pump tank (50) liquid hydrogen (2.1) can be forced from the pump tank (50) via the supply line (30) into the main tank (10).

11. Hydrogen tank system (1) according to one of claims 1 to 3, wherein the pressure increasing device (40) is arranged to increase the gas pressure P20 in the storage tank (20).

12. Hydrogen tank system (1) according to claim 11 in conjunction with claim 2, wherein the heater (41) is arranged in the storage tank (20) in a separate compartment (25) which is connected to the remaining internal volume (21) is in fluid communication, but is at least partially thermally insulated therefrom.

13. Storage tank (20), in which a pressure increasing device (40) for increasing a gas pressure P20 in the storage tank (20) is arranged, for a hydrogen tank system (1) according to claim 11 or 12.

14. Pump tank (50), in which a pressure increasing device (40) for increasing a gas pressure pso in the pump tank (50) is arranged, for a hydrogen tank system (1) according to one of claims 4 to 10.

15. Fuel cell system (100), in particular fuel cell aircraft propulsion (109), with a hydrogen tank system (1) according to one of claims 1 to 12.

16. Aircraft (110), in particular airplane (111), with a fuel cell system (100) according to claim 15.

17. A method for operating a hydrogen tank system (1) according to one of claims 1 to 12, a fuel cell system (100) according to claim 15 or an aircraft (110) according to claim 16, in which liquid hydrogen (2.1) is stored in the storage tank (20); a gas pressure pso, P20 in a pump tank (50) and / or the storage tank (20) is increased with the pressure increasing device (40); with the increased gas pressure pso, P20, liquid hydrogen (2.1) is forced into the main tank (10) via the supply line (30).

18. Use of a main tank (10), a storage tank (20) and / or a pressure booster device (40) in a hydrogen tank system (1) according to one of claims 1 to 12 or a fuel cell system (100) according to claim 15 or an aircraft (110) according to claim 16.

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