Storage vessel assembly and method

Abstract

A storage vessel assembly (1) for supplying hydrogen at constant pressure to a fuel cell (32), the storage vessel assembly having: a storage vessel (2) for accommodating cryogenic hydrogen (H2), wherein the storage vessel (2) has a gas zone (7) and a liquid zone (8); an evaporator (24) for converting a liquid phase (LH2) of the hydrogen (H2) into a gaseous phase (GH2) of the hydrogen (H2); a liquid pump (15) for conveying the liquid phase (LH2) from the liquid zone (8) to the evaporator (24); a feed device (11) for feeding a mixture, which comprises a proportion of the liquid phase (LH2) conveyed by the liquid pump (15) and a proportion of the gaseous phase (GH2) converted by the evaporator (24), to the liquid zone (8) of the storage vessel (6); and a gas line (31) via which the evaporator (24) is fluidically connected to the feed device and to the fuel cell (32).

Description

[0001] Description

[0002] Storage tank arrangement and method

[0003] The invention relates to a storage container arrangement for supplying a fuel cell with hydrogen at constant pressure and a method for operating such a storage container arrangement.

[0004] Storage tanks for liquid hydrogen have a liquid zone with liquid hydrogen and a gas zone with gaseous hydrogen arranged above the liquid zone. According to internal company knowledge, such a storage tank can have a pressure build-up circuit. The use of such a pressure build-up circuit can lead to a thermodynamic imbalance between the liquid hydrogen and the gaseous hydrogen due to superheated steam in the gas zone. Due to movements of the storage tank, particularly during mobile use, a mixture of the liquid hydrogen and the gaseous hydrogen within the storage tank can lead to a pressure drop within the storage tank. However, a consumer, such as a fuel cell, requires a nearly constant supply pressure, which cannot be guaranteed by such a pressure build-up circuit.This needs to be improved.

[0005] Against this background, it is an object of the present invention to provide an improved storage container arrangement.

[0006] Accordingly, a storage container arrangement for supplying a fuel cell with hydrogen at constant pressure is proposed.The storage container arrangement comprises a storage container for holding cryogenic hydrogen, the storage container having a gas zone and a liquid zone, an evaporator arranged outside the storage container for converting a liquid phase of the hydrogen into a gaseous phase of the hydrogen, a liquid pump for conveying the liquid phase from the liquid zone to the evaporator, and a feed device for feeding a mixture comprising a portion of the liquid phase conveyed by the liquid pump and a portion of the gaseous phase converted by the evaporator to the liquid zone of the storage container, and a gas line via which the evaporator is in fluid communication with the feed device and which establishes a fluid connection between the evaporator and the fuel cell.

[0007] By supplying the mixture comprising the liquid phase and the gaseous phase to the liquid zone via the feed device, a thermodynamic equilibrium can be maintained within the storage vessel, even when the storage vessel is used for mobile applications in which mixing of the liquid phase with the gaseous phase may occur within the storage vessel. This prevents a pressure drop within the storage vessel when the liquid phase mixes with the gaseous phase.

[0008] The storage container arrangement can also be referred to as a hydrogen storage container arrangement. Accordingly, the storage container can also be referred to as a hydrogen storage container. Preferably, a phase boundary is provided in the storage container between the gas zone and the liquid zone. The gas zone is characterized in particular by the fact that it can accommodate the gaseous phase. The liquid zone is characterized in particular by the fact that it can accommodate the liquid phase.

[0009] Within the storage vessel, the liquid phase of hydrogen is located in the liquid zone. The gaseous phase of hydrogen is located in the gas zone. The phase boundary separates the gaseous phase from the liquid phase. The gaseous phase is located above the liquid phase, as viewed along a direction of gravity. The liquid phase is liquid hydrogen. Accordingly, the term "liquid phase" can be replaced with the term "liquid hydrogen" and vice versa. The gaseous phase is gaseous hydrogen. Accordingly, the term "gaseous phase" can be replaced with the term "gaseous hydrogen" and vice versa.

[0010] The evaporator is designed to evaporate the liquid phase supplied to the evaporator with the aid of the liquid pump. In this process, the liquid phase is converted into the gaseous phase. The evaporator can be electrically operated, for example. The evaporator can be a heat exchanger or comprise a heat exchanger. The evaporator is arranged downstream of the liquid pump. The terms "downstream" and "upstream" are to be understood here with reference to a flow direction of the liquid phase from the liquid zone to the evaporator. The same applies to a flow direction of the gaseous phase from the evaporator to the liquid zone of the storage tank.

[0011] A valve can be provided upstream of the liquid pump. The liquid pump can be fluidly connected to the liquid zone of the storage tank via a line. The aforementioned valve is provided in or on the line. The liquid pump is, in particular, a submersible pump. The liquid pump is immersed in the liquid phase. The liquid pump is, in particular, a cryopump or can be referred to as a cryopump. The liquid pump is, in particular, assigned a pump sump that can accommodate the liquid pump. Viewed along the direction of gravity, the liquid pump is preferably located below the storage tank.

[0012] The aforementioned feed device is, in particular, a lower feed device or a first feed device. Accordingly, the storage container arrangement may also have an upper feed device or a second feed device. Only the first feed device, which is referred to below as the feed device, will be discussed below. The feed device is, in particular, tubular. The feed device is arranged within the storage container. In particular, the feed device is immersed in the liquid phase. The feed device is thus located in the liquid zone of the storage container.

[0013] The portion of the liquid phase pumped by the liquid pump is fed to the feed device downstream of the liquid pump and upstream of the evaporator. The portion of the gaseous phase converted by the evaporator is fed to the feed device downstream of the evaporator. The liquid phase and the gaseous phase are mixed with each other by means of the feed device before being fed to the storage vessel. A mixing section or any mixer can be provided for this purpose. The gaseous phase converted by the evaporator is, in particular, superheated hydrogen vapor. "Superheated vapor" is understood here to mean vapor with a temperature above the boiling point. With the aid of the feed device, superheated hydrogen vapor is returned to the storage vessel, in particular to the liquid zone of the storage vessel, downstream of the evaporator.In this recycle stream of superheated steam, the liquid phase is diverted downstream of the liquid pump and fed to the feed device. The liquid phase and the gaseous phase are mixed. This cools the gaseous phase. The pre-cooled mixture is then introduced via the feed device into the liquid phase located within the storage vessel. The mixture is preferably gaseous. The mixture can also be a two-phase mixture and is therefore also referred to as such. The mixture rises, particularly in the form of gas bubbles, in the liquid phase and then enters the gas zone.

[0014] According to one embodiment, the storage container arrangement has a mixing section arranged upstream of the feed device for mixing the gaseous phase and the liquid phase to form the mixture.

[0015] The mixing section can include so-called vortex generators. Within the mixing section, the liquid phase is mixed with the gaseous phase. This cools the gaseous phase, which is preferably present as superheated steam.

[0016] According to a further embodiment, the mixing section is arranged outside the storage container.

[0017] This means in particular that the mixing section is placed outside both the gas zone and the liquid zone.

[0018] According to the invention, the storage container arrangement has a liquid line, by means of which the liquid pump is in fluid communication with the evaporator. Preferably, the mixing section is in fluid communication with the liquid line. The liquid line connects the liquid pump to the evaporator. A line emerges from the liquid line, which preferably fluidically connects the liquid line to the mixing section.

[0019] According to a further embodiment, the storage container arrangement has a liquid valve for releasing and interrupting the fluid connection between the liquid line and the mixing section.

[0020] The liquid valve is located in or on the line between the liquid line and the mixing section. The line can be shut off or opened using the liquid valve. The liquid valve can be controlled, for example, by a regulating and control unit of the storage tank arrangement. The liquid valve can be controlled, for example, based on sensor signals from a sensor system. The sensor system can have different temperature and / or pressure sensors. For example, pressure sensors of the sensor system are located within the storage tank. The liquid valve can be used to influence the volume flow of the liquid phase from the liquid line to the mixing section. Accordingly, any desired amount of the liquid phase can be added to the gaseous phase returned to the storage tank using the liquid valve.

[0021] According to the invention, the storage container arrangement comprises a gas line for establishing a fluid connection between the evaporator and the fuel cell. Preferably, the mixing section is in fluid communication with this gas line.

[0022] The gas line establishes a fluid connection between the evaporator and the fuel cell. The fuel cell can be part of the storage container arrangement, but this is not mandatory. For example, the gaseous phase can be supplied to the fuel cell at a temperature of, for example, 0 °C to 20 °C or 5 °C to 50 °C at a pressure of 3.5 bar to 11 bar. A "fuel cell" in this context is understood to be a galvanic cell that converts the chemical reaction energy of a continuously supplied hydrogen and an oxidizing agent, in this case oxygen, into electrical energy. The resulting electrical energy can be used, for example, to drive an electric motor. A line flows out of the gas line, fluidly connecting the gas line to the mixing section. The line flows out of the gas line downstream of the evaporator.The gas line may have a valve located upstream of the consumer. The valve can be controlled by the control unit.

[0023] According to a further embodiment, the storage container arrangement has a gas valve for releasing and interrupting the fluid connection between the gas line and the mixing section.

[0024] The gas valve is provided, in particular, in or on the aforementioned line, which flows from the gas line located between the evaporator and the consumer. The gas valve can be controlled by the control unit. The gas valve can be used to regulate the amount of gaseous phase supplied to the mixing section.

[0025] According to a further embodiment, the liquid pump is arranged outside the storage container.

[0026] This means in particular that the liquid pump is placed outside both the gas zone and the liquid zone of the storage tank.

[0027] According to a further embodiment, the feed device has a plurality of outlet nozzles opening into the liquid zone.

[0028] The number of outlet nozzles is unlimited. The outlet nozzles can be used to inject the mixture of the liquid and gaseous phases into the liquid zone of the storage tank. The outlet nozzles are typically gas outlet nozzles.

[0029] According to a further embodiment, the storage tank arrangement comprises a pump sump in which the liquid pump is accommodated, wherein the pump sump is in fluid communication with the gas zone. A gas zone with the gaseous phase and a liquid zone with the liquid phase are preferably provided in the pump sump. A phase boundary is provided between the gas zone and the liquid zone within the pump sump. The liquid pump is immersed in the liquid phase. The gas zone of the pump sump is in fluid communication with the gas zone of the storage tank via a conduit. This allows vaporized hydrogen from the pump sump to be returned to the gas zone of the storage tank.

[0030] According to a further embodiment, the storage container arrangement has a further supply device for supplying a part of the liquid phase conveyed by the liquid pump to the gas zone.

[0031] This supply device can be used to cool the gas zone. The additional supply device can also be referred to as a second supply device or upper supply device. The additional supply device has a plurality of outlet nozzles opening into the gas zone. The additional supply device is fluidly connected via a line to the liquid line arranged between the liquid pump and the evaporator. A valve can be provided in or on the aforementioned line to open and shut off the line and thus to activate and deactivate the additional supply device. The valve can be controlled using the control unit.

[0032] According to a further embodiment, the storage container arrangement comprises thermally conductive plates arranged within the storage container for heat transfer between the gas zone and the liquid zone and vice versa.

[0033] The thermally conductive plates are preferably made of a metal with good thermal conductivity. For example, the thermally conductive plates can be made of an aluminum alloy. The number of thermally conductive plates is arbitrary. The thermally conductive plates divide both the gas zone and the liquid zone into several sections. However, the thermally conductive plates are fluid-permeable. For this purpose, the thermally conductive plates can have perforations or openings. Both the gaseous and liquid phases can pass through the thermally conductive plates. Optionally, the storage vessel arrangement can have a buffer tank for gaseous hydrogen downstream of the evaporator to reduce pressure fluctuations that can arise, for example, from pulsations in the liquid pump.

[0034] Furthermore, a method for operating such a storage container arrangement is proposed. The storage container arrangement comprises a storage container for holding the cryogenic hydrogen, wherein the storage container has a gas zone and a liquid zone. The method comprises the following steps: a) conveying a liquid phase of the cryogen from the liquid zone to an evaporator arranged outside the storage container, b) converting the liquid phase to a gaseous phase of the hydrogen with the aid of the evaporator, and c) supplying a mixture comprising a portion of the conveyed liquid phase and a portion of the converted gaseous phase to the liquid zone, and d) supplying the gaseous phase of the hydrogen to the fuel cell.

[0035] Step a) is preferably carried out using the aforementioned liquid pump. The liquid pump conveys the liquid phase from the liquid zone of the storage vessel to the evaporator. During step b), the liquid phase is evaporated into the gaseous phase using the evaporator. The gaseous phase is, in particular, superheated steam. During step c), the mixture of the liquid phase and the gaseous phase is generated and fed to the liquid zone of the storage vessel. Step c) is carried out using the lower feed device or first feed device.

[0036] According to one embodiment, the mixture is produced by mixing the liquid phase and the gaseous phase by means of a mixing section arranged outside the storage container.

[0037] With the help of the mixing section, the gaseous phase, which is in particular superheated steam, is cooled down with the help of the added liquid phase.

[0038] According to a further embodiment, a portion of the pumped liquid phase is fed to the gas zone. For this purpose, the aforementioned upper feed device or second feed device is used, which can feed a portion of the liquid phase pumped by the liquid pump to the gas zone of the storage vessel. This allows the gas zone to be cooled.

[0039] "One" in this case is not necessarily to be understood as limiting the number to exactly one element. Rather, multiple elements, such as two, three, or more, can also be considered. Any other counting term used here should also not be understood as requiring a precise limitation to the corresponding number of elements. Rather, numerical deviations upwards and downwards are possible.

[0040] The embodiments and features described for the proposed storage container arrangement apply accordingly to the proposed method and vice versa.

[0041] Further possible implementations of the storage container arrangement and / or the method also include combinations of features or embodiments described above or below with respect to the exemplary embodiments that are not explicitly mentioned. In this case, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the storage container arrangement and / or the method.

[0042] Further advantageous embodiments of the storage container arrangement and / or the method are the subject of the dependent claims and the exemplary embodiments of the storage container arrangement and / or the method described below. The storage container arrangement and / or the method are explained in more detail below using preferred embodiments with reference to the accompanying figures.

[0043] Fig. 1 shows a schematic sectional view of an embodiment of a

[0044] Storage container arrangement 1; and Fig. 2 shows a schematic block diagram of an embodiment of a method for operating the storage container arrangement according to Fig. 1.

[0045] In the figures, identical or functionally equivalent elements have been given the same reference numerals unless otherwise stated.

[0046] Fig. 1 shows a schematic sectional view of an embodiment of a storage container arrangement 1.

[0047] The storage container assembly 1 comprises a storage tank or storage vessel 2. The storage vessel 2 is suitable for holding hydrogen H2 (boiling point: 1 bara: 20.268 K = -252.882 °C). Therefore, the storage vessel 2 can also be referred to as a hydrogen storage vessel or hydrogen storage tank.

[0048] The storage container 2 can be a transport container. For example, liquid hydrogen LH2 can be transported using the storage container 2. The storage container 2 can be part of a vehicle, in particular a watercraft. In this case, the storage container 2 is suitable for mobile applications. However, the storage container 2 can also be used stationary, for example, in building technology.

[0049] The storage tank 2 is constructed rotationally symmetrically to a symmetry or central axis 3. The central axis 3 is oriented perpendicular to a direction of gravity g. The storage tank 2 is double-walled and comprises a first container or inner container, which is also constructed rotationally symmetrically to the central axis 3. The inner container is arranged entirely within a second container or outer container. The outer container is also constructed rotationally symmetrically to the central axis 3. The inner container and the outer container are made of stainless steel.

[0050] A gap is provided between the inner container and the outer container, completely enclosing or surrounding the inner container. A vacuum is applied to the gap. A "vacuum" in this case is defined in particular as a pressure of less than 300 mbar, preferably less than 10 -3 mbar, more preferably less than 10 -7mbar. Storage tank 2 is thus vacuum-insulated.

[0051] The storage tank 2 comprises a tubular or cylindrical base section 4, which is also constructed rotationally symmetrically to the central axis 3. The base section 4 can have a circular or approximately circular cross-section. The base section 4 is double-walled. The base section 4 is closed on both ends by a cover section 5, 6. The cover sections 5, 6 are curved. A first cover section 5 and a second cover section 6 are curved in opposite directions, so that the cover sections 5, 6 are curved outward relative to the base section 4.

[0052] The liquid hydrogen LH2 is contained in the storage container 2, particularly in the inner container. As long as the hydrogen H2 is in the two-phase region, a gas zone 7 with vaporized hydrogen GH2 and a liquid zone 8 with liquid hydrogen LH2 can be provided in the storage container 2. Thus, after being filled into the storage container 2, the hydrogen H2 has two phases with different states of aggregation, namely liquid and gaseous. This means that a phase boundary 9 is present in the storage container 2 between the liquid hydrogen LH2 and the gaseous hydrogen GH2.

[0053] Arranged within the storage tank 2 are a plurality of thermally conductive plates 10, only one of which is provided with a reference symbol. The number of thermally conductive plates 10 is arbitrary. For example, seven thermally conductive plates 10 are provided. Viewed along the central axis 3, the thermally conductive plates 10 are positioned at a distance from one another. The thermally conductive plates 10 run perpendicular to the central axis 3. The thermally conductive plates 10 divide both the gas zone 7 and the liquid zone 8 into a plurality of sections. However, the thermally conductive plates 10 are fluid-permeable, so that both the gaseous hydrogen GH2 and the liquid hydrogen LH2 can flow through the thermally conductive plates 10. For this purpose, the thermally conductive plates 10 can have passages or openings through which the gaseous hydrogen GH2 and the liquid hydrogen LH2 can pass. The storage tank 2 has a plurality of distribution pipes or supply devices 11, 12.A lower feed device 11, which is arranged below the phase boundary 9 in the liquid hydrogen LH2, and an upper feed device 12, which is arranged above the phase boundary 9 in the gaseous hydrogen GH2, can be provided. The lower feed device 11 has outlet nozzles 13, with the aid of which gaseous hydrogen GH2 and / or liquid hydrogen LH2 can be supplied to the storage container 2 below the phase boundary 9. The upper feed device 12 has outlet nozzles 14, with the aid of which liquid hydrogen LH2 can be supplied to the storage container 2 above the phase boundary 9.

[0054] The storage tank assembly 1 further comprises a liquid pump 15, which is fluidly connected to the storage tank 2 via a line 16. The line 16 exits the storage tank 2 below the phase boundary 9. Liquid hydrogen LH2 can be supplied to the liquid pump 15 via the line 16. A valve 17 is provided in or on the line 16. The valve 17 can be used to close or open the line 16.

[0055] A pump sump 18 is assigned to the liquid pump 15. The liquid pump 15 is located within the pump sump 18. The pump sump 18 is filled with hydrogen H2. Within the pump sump 18, a gas zone 19 containing gaseous hydrogen GH2 and a liquid zone 20 containing liquid hydrogen LH2 are provided. The liquid pump 15 is immersed in the liquid hydrogen LH2. A phase boundary 21 is provided between the gas zone 19 and the liquid zone 20.

[0056] Above the phase boundary 21, i.e., from the gas zone 19 of the pump sump 18, a line 22 emerges from the pump sump 18, which leads to the storage tank 2 and opens into the gas zone 7 of the storage tank 2. With the aid of the line 22, gaseous hydrogen GH2 from the gas zone 19 of the pump sump 18 can be supplied to the gas zone 7 of the storage tank 2.

[0057] With the help of a liquid line 23, the liquid pump 15 can feed liquid hydrogen LH2 to an evaporator 24. Between the liquid pump 15 and the evaporator 24, a line 25 branches off from the liquid line 23. The line 25 leads to a line 26. In or on the line 25, a liquid valve 21 is provided, with the help of which the line 25 can be closed and opened. The line 26 is connected to the lower feed device 11 by means of a mixing section 28, which can have vortex generators. Downstream of the line 25, another line 29 opens out of the liquid line 23. The line 29 is connected to the upper feed device 12. In or on the line 29, a valve 30 for opening and closing the line 29 is provided.

[0058] The evaporator 24 can evaporate the liquid hydrogen LH2 into gaseous hydrogen GH2. The gaseous hydrogen GH2 is supplied to a fuel cell 32 via a gas line 31. For example, the gaseous hydrogen GH2 can be supplied to the fuel cell 32 at a temperature of, for example, 0°C to 20°C or 5°C to 50°C at a pressure of 3.5 bar to 11 bar.

[0059] A "fuel cell" is understood here to be a galvanic cell that converts the chemical reaction energy of a continuously supplied fuel, in this case hydrogen H2, and an oxidizing agent, in this case oxygen, into electrical energy. The resulting electrical energy can be used, for example, to drive an electric motor (not shown).

[0060] A valve 33 is provided on or in the gas line 31, by means of which the gas line 31 can be opened and closed. A line 34 exits the gas line 31 upstream of the valve 33. The line 34 is connected to the line 26. A gas valve 35 is provided in or on the line 34, by means of which the line 34 can be opened and closed.

[0061] The storage tank arrangement 1 further comprises a control unit 36 ​​for controlling the liquid pump 15, the valves 17, 27, 30, 33, 35, and the evaporator 24. For this purpose, an operative connection can be provided between the control unit 36 ​​and the liquid pump 15, the valves 17, 27, 30, 33, 35, and the evaporator 24. The operative connection can be wired or wireless. For example, the control unit 36 ​​can switch the liquid pump 15 and the evaporator 24 on and off. Furthermore, the control unit 36 ​​can open and close the valves 17, 27, 30, 33, 35. The control unit 36 ​​can comprise a computer. A program for operating the storage tank arrangement 1 can be stored in the control unit 36.

[0062] The control and regulation unit 36 ​​can control the liquid pump 15, the valves 17, 27, 30, 33, 35, and the evaporator 24 based on sensor signals from a sensor system 37. The sensor system 37 can comprise a plurality of sensors, for example, pressure sensors, temperature sensors, or the like. The sensor system 37, or at least a portion of the sensor system 37, can be located within the storage tank 2.

[0063] According to internal company findings, previously used hydrogen storage containers can have a pressure buildup circuit. The use of such a pressure buildup circuit can result in a thermodynamic imbalance between the liquid hydrogen LH2 and the gaseous hydrogen GH2 due to superheated steam in the gas zone. Due to movements of the storage container, particularly during mobile use, a mixture of the liquid hydrogen LH2 and the gaseous hydrogen GH2 within the storage container can lead to a pressure drop within the storage container. However, the aforementioned fuel cell 32 requires a nearly constant supply pressure, which cannot be guaranteed by such a pressure buildup circuit. This disadvantage is remedied by the storage container arrangement 1 explained above.

[0064] In the storage tank arrangement 1, the pressure build-up for the consumer 32 takes place with the aid of the liquid pump 15 and the evaporator 24. With the aid of the liquid pump 15, liquid hydrogen LH2 is withdrawn from the storage tank 2, fed to the evaporator 24 and then converted into gaseous hydrogen GH2 in the consumer 32.

[0065] During operation of the liquid pump 15, the gas valve 35 can be opened. This feeds superheated gaseous hydrogen GH2 to the mixing section 28. Pressurized liquid hydrogen LH2 is admixed to this gaseous hydrogen GH2 by opening the liquid valve 27. A mixture comprising gaseous hydrogen GH2 and liquid hydrogen LH2 is generated in the mixing section 28. The mixture can be a two-phase mixture and is therefore also referred to as such. This pre-cooled mixture is fed to the liquid zone 8 of the storage vessel 2 by means of the lower feed device 11. This allows thermal equilibrium to be maintained during a pressure build-up process in the storage vessel 2.

[0066] In particular, superheated hydrogen vapor is returned to the liquid zone 8 of the storage tank 2 by means of the lower feed device 11, the lines 26, 34, and the gas valve 35 downstream of the evaporator 24. As previously mentioned, liquid hydrogen LH2, which comes from the liquid pump 15, is mixed into this return stream via the line 25 and the liquid valve 27.

[0067] In the mixing section 28, the gaseous hydrogen GH2 and the liquid hydrogen LH2 are thoroughly mixed, for example, with the aid of a vortex generator as mentioned above. The hydrogen H2 leaves the mixing section 28 as a mixture, in particular as a two-phase mixture comprising gaseous hydrogen GH2 and liquid hydrogen LH2. The pre-cooled mixture is fed to the liquid zone 8 via the lower feed device 11.

[0068] In support of this, by opening the valve 30, pressurized and liquid hydrogen LH2 can be dispersed via the upper feed device 12 into the gas zone 7 of the storage vessel 2 in order to additionally stabilize the thermodynamic equilibrium within the storage vessel 2.

[0069] The additional insertion of the thermally conductive plates 10 prevents the gaseous hydrogen GH2 in the gas zone 7 from heating above the saturation temperature. A submersible pump can be used as the liquid pump 15, which is completely surrounded by the liquid hydrogen LH2 to be pumped in the separate pump sump 18. During operation of the liquid pump 15, liquid hydrogen LH2 evaporates in the pump sump 18. The resulting gaseous hydrogen GH2 is introduced into the gas zone 7 of the storage tank 2 via line 22.

[0070] Optionally, a buffer tank for gaseous hydrogen GH2 can be integrated downstream of the evaporator 24 to further minimize pressure fluctuations that can arise, for example, from pulsations of the liquid pump 15. With the aid of the storage tank arrangement 1, reliable operation of the consumer 32 is thus possible. This results in a constant equilibrium state and thus controllable conditions within the storage tank 2, even during movements of the storage tank 2, for example, in a mobile application of the storage tank arrangement 1.

[0071] Fig. 2 shows a schematic block diagram of an embodiment of a method for operating the storage container arrangement 1.

[0072] In the method, in a step S1, the liquid hydrogen LH2 is conveyed from the liquid zone 8 of the storage tank 2 to the evaporator 24. In a step S2, the liquid hydrogen LH2 is converted, in particular evaporated, into gaseous hydrogen GH2 with the aid of the evaporator 24. In a step S3, the mixture, which comprises a portion of the conveyed liquid hydrogen LH2 and a portion of the converted gaseous hydrogen GH2, is fed to the liquid zone 8. Gaseous hydrogen GH2 is supplied to the fuel cell 32 via the gas line 31 at a nearly constant pressure.

[0073] In particular, the mixture is created by mixing the liquid hydrogen LH2 and the gaseous hydrogen GH2 using the mixing section 28 arranged outside the storage tank 2. In addition, a portion of the extracted liquid hydrogen LH2 can be fed to the gas zone 7 of the storage tank 2.

[0074] Although the present invention has been described using exemplary embodiments, it can be modified in many ways.

[0075] Reference symbols used

[0076] 1 storage tank arrangement

[0077] 2 storage tanks

[0078] 3 Central axis

[0079] 4 Basic section

[0080] 5 Lid section

[0081] 6 Lid section

[0082] 7 Gas Zone

[0083] 8 Liquid zone

[0084] 9 Phase boundary

[0085] 10 thermal conducting plate

[0086] 11 Feeding device

[0087] 12 Feeding device

[0088] 13 Outlet nozzle

[0089] 14 Outlet nozzle

[0090] 15 Liquid pump

[0091] 16 Line

[0092] 17 Valve

[0093] 18 Pump sump

[0094] 19 Gas Zone

[0095] 20 Liquid zone

[0096] 21 Phase boundary

[0097] 22 Line

[0098] 23 Liquid line

[0099] 24 evaporators

[0100] 25 Line

[0101] 26 Line

[0102] 27 Liquid valve

[0103] 28 mixing section

[0104] 29 Line

[0105] 30 valve

[0106] 31 Gas pipeline

[0107] 32 consumers

[0108] 33 Valve 34 Line

[0109] 35 Gas valve

[0110] 36 Control and regulation unit

[0111] 37 Sensors g Gravity direction

[0112] GH2 hydrogen

[0113] H2 hydrogen

[0114] LH2 Hydrogen S1 Step

[0115] 52 steps

[0116] 53 steps

Claims

Patent claims 1. Storage container arrangement (1) for supplying a fuel cell (32) with hydrogen at constant pressure, comprising: a storage container (2) for receiving cryogenic hydrogen (H2), the storage container (2) having a gas zone (7) and a liquid zone (8), - an evaporator (24) arranged outside the storage container (2) for converting a liquid phase (LH2) of the hydrogen (H2) into a gaseous phase (GH2) of the hydrogen (H2), a liquid pump (15) for conveying the liquid phase (LH2) from the liquid zone (8) of the storage container (2) via a liquid line (23) to the evaporator (24), a feed device (11) for feeding a mixture comprising a part of the liquid phase (LH2) conveyed by the liquid pump (15) and a part of the gaseous phase (GH2) converted by the evaporator (24) to the liquid zone (8) of the storage container (2), and - a gas line (31) via which the evaporator (24) is in fluid communication with the supply device (11) and which establishes a fluid connection between the evaporator (24) and the fuel cell (32).

2. Storage container arrangement according to claim 1, further comprising a mixing section (28) arranged upstream of the feed device (11) for mixing the gaseous phase (GH2) and the liquid phase (LH2) to form the mixture.

3. Storage container arrangement according to claim 2, wherein the mixing section (28) is arranged outside the storage container (2).

4. Storage container arrangement according to claim 2 or 3, wherein the mixing section (28) is in fluid communication with the liquid line (23).

5. Storage container arrangement according to claim 4, further comprising a liquid valve (27) for releasing and interrupting the fluid connection between the liquid line (23) and the mixing section (28).

6. Storage container arrangement according to claim 4 or 5, wherein the mixing section (28) is in fluid communication with the gas line (31).

7. Storage container arrangement according to claim 6, further comprising a gas valve (35) for releasing and interrupting the fluid connection between the gas line (31) and the mixing section (28).

8. Storage tank arrangement according to one of claims 1 - 7, wherein the liquid pump (15) is arranged outside the storage tank (2).

9. Storage container arrangement according to one of claims 1 - 8, wherein the feed device (11) has a plurality of outlet nozzles (13) opening into the liquid zone (8).

10. Storage container arrangement according to one of claims 1 - 9, further comprising a pump sump (18) in which the liquid pump (15) is received, the pump sump (18) being in fluid communication with the gas zone (7).

11. Storage container arrangement according to one of claims 1-10, further comprising a further feed device (12) for feeding a part of the liquid phase (LH2) conveyed by the liquid pump (15) to the gas zone (7).

12. Storage container arrangement according to one of claims 1 - 11, further comprising thermally conductive plates (10) arranged within the storage container (2) for heat transfer between the gas zone (7) and the liquid zone (8) and vice versa.

13. A method for operating a storage container arrangement (1) for supplying a fuel cell (32) with hydrogen at constant pressure, wherein the storage container arrangement (1) comprises a storage container (2) for receiving a cryogenic hydrogen (H2), wherein the storage container (2) has a gas zone (7) and a liquid zone (8), and wherein the method comprises the following steps: a) conveying (S1) a liquid phase (LH2) of the hydrogen (H2) from the liquid zone (8) to an evaporator (24) arranged outside the storage vessel (2), b) converting (S2) the liquid phase (LH2) of the hydrogen to a gaseous phase (GH2) of the hydrogen (H2) with the aid of the evaporator (24), and c) feeding (S3) a mixture comprising a part of the conveyed liquid phase (LH2) and a part of the converted gaseous phase (GH2) to the liquid zone (8) of the storage vessel (2), and d) feeding the gaseous phase (GH2) of the hydrogen to the Fuel cell (32).

14. The method according to claim 13, wherein the mixture is produced by mixing the liquid phase (LH2) and the gaseous phase (GH2) by means of a mixing section (28) arranged outside the storage container (2).

15. The method according to claim 13 or 14, wherein the gaseous phase converted by the evaporator (24) is superheated hydrogen vapor.

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