Hydrogen storage container, and method

Abstract

A hydrogen storage container (1A-1H) for storing liquid hydrogen (LH2), having an inner container (3) for receiving the liquid hydrogen (LH2), an outer container (10) surrounding the inner container (3), and an induction heating device (20A-20E) for introducing heat (Q) into the liquid hydrogen (H2), wherein the inner container (3) is manufactured from an austenitic steel alloy.

Description

[0001]June 26, 2025 – Claudia Meilinger1 Description of Hydrogen Storage Tank and Method The invention relates to a hydrogen storage tank for storing liquid hydrogen and a method for operating such a hydrogen storage tank. DE 102015219983 A1 forms the preamble of claim 1 and discloses, in an embodiment according to Fig. 5, a pressure vessel 10 for hydrogen for a fuel cell-powered motor vehicle, comprising an inner tank 30 and an outer tank 20. A partially evacuated or evacuated space 25 is provided between the outer tank 20 and the inner tank 30. The inner tank 30 has an inner shell 45 made of aluminum and an outer shell 40 made of a composite material, such as a carbon fiber reinforced plastic, directly adjacent to the inner shell 45. An inductively heatable heating element 60, for example made of a ferromagnetic material, is arranged in the inner tank 30.The object of the present invention is to provide a hydrogen storage container that is improved compared to DE 10 2015219983A1. Accordingly, a hydrogen storage container for storing liquid hydrogen is proposed. The hydrogen storage container comprises an inner container enclosing an interior space for receiving the liquid hydrogen, an outer container enclosing the inner container, wherein a gap is arranged between the inner container and the outer container, and wherein the gap is pressurized with a vacuum, and an induction heating device for introducing heat into the liquid hydrogen with an induction heating element arranged within the inner container. According to the invention, the inner container is made of an austenitic steel alloy.Furthermore, according to the invention, the induction heating element extends radially inwards from the inner container and divides the interior of the inner container into several areas. 26.06.2025 – Claudia Meilinger2 The simple and cost-effective manufacturing of the inner container from austenitic steel allows, due to the strength properties of austenitic steel, the storage of large quantities of liquid hydrogen, up to several hundred cubic meters, even at cryogenic temperatures. The arrangement of the induction heating element or several induction heating elements within the inner container enables spatially uniform heating of the liquid and, if applicable, gaseous hydrogen stored in the inner container. In addition, the hydrogen can be kept in a state of thermodynamic equilibrium. Temperature stratification of the hydrogen within the inner container is prevented or avoided.In particular, a particularly large heating surface can be heated, which is in contact with the liquid hydrogen and, if applicable, gaseous hydrogen. This allows the heat input to be distributed across the large heating surface. Furthermore, the specific heat input per heating surface can be reduced, thus preventing the formation of hydrogen gas bubbles on the induction heating element. Additionally, the induction heating device can be controlled precisely, for example, regulated more quickly and / or accurately to a desired temperature. The hydrogen can also be referred to as a cryogen in this context. In principle, any other cryogenic substance can be stored in the hydrogen storage container instead of hydrogen.Examples of cryogenic fluids, cryogenic liquids, or simply cryogens, include not only the aforementioned liquid hydrogen but also cryogenically liquefied gases such as helium, liquid nitrogen, or liquid oxygen. A "cryogen" is therefore primarily understood to be a liquid. The cryogen can thus also be called a cryogenic fluid. Liquid hydrogen can be vaporized and thus converted into a gaseous phase. After vaporization, the hydrogen is a gas or can be described as gaseous or vaporized hydrogen. The term "hydrogen" can therefore encompass both a gaseous and a liquid phase. The liquid phase, in particular, can also be referred to as a cryogenic fluid. The term "vaporized hydrogen" (26.06.2025 – Claudia Meilinger3) refers here preferably only to the gaseous phase of hydrogen.In the inner container of the hydrogen storage tank, a gas zone and a liquid zone below it form after or during the filling process with liquid hydrogen. A phase boundary is provided between the gas zone and the liquid zone. The induction heating element(s) are preferably arranged in both the liquid zone and the gas zone of the inner container. Thus, after filling the hydrogen storage tank, the liquid hydrogen preferably has two phases with different states of matter, namely liquid and gaseous. The liquid phase can transition into the gaseous phase and vice versa. The liquid phase can be referred to as the liquid phase. The gaseous phase can be referred to as the gas phase. Filling the hydrogen storage tank with a purely liquid solution is also possible. The pressure prevailing in the hydrogen storage tank is preferably around 3.5 bara.The pressure within the hydrogen storage tank is, in particular, constant. The hydrogen storage tank is especially suitable for supplying the gaseous phase of hydrogen to a consumer at a suitable supply pressure and temperature. The consumer can be a fuel cell. In this context, a "fuel cell" is understood to be, in particular, a galvanic cell that converts the chemical reaction energy of a continuously supplied fuel, in this case hydrogen, and an oxidant, in this case oxygen, into electrical energy. The hydrogen is supplied to the consumer, in particular, in gaseous form. This means that the hydrogen is completely vaporized or heated before or upstream of the consumer if the gaseous phase is supplied directly from the hydrogen storage tank.For example, the hydrogen is supplied to the consumer at a supply pressure of 1 to 2.5 bara and a temperature of +10 °C to +25 °C. However, the supply pressure can also be up to 6 bara. The hydrogen storage tank preferably has a central axis of symmetry with respect to which it is essentially rotationally symmetrical. The hydrogen storage tank can therefore have a circular or annular cross-section. Alternatively, the hydrogen storage tank can also have an oval or elliptical cross-section. The inner and outer tanks are also rotationally symmetrical with respect to the central axis. The inner and outer tanks are, in particular, fluid-tight. The outer tank can, for example, be made of a metallic material, especially stainless steel.The inner container is completely enclosed within the outer container. This means, in particular, that the outer container completely surrounds the inner container. The induction heating device is specifically designed to introduce heat directly into the liquid phase of the hydrogen. By introducing heat into the liquid hydrogen, it at least partially evaporates, thereby creating a pressure build-up within the hydrogen storage container, especially within the inner container. According to one embodiment, the induction heating device has an inductor located outside the inner container. The inductor is an electrical component designed to carry an electric current. The inductor is therefore an electrical conductor. Furthermore, the inductor is designed to generate or create a magnetic field when an electric current flows through it.The inductor can have various forms. For example, it can be designed as a coil, a flat coil, and / or as individual turns. Preferably, the inductor's shape is adapted to heat the hydrogen storage tank and / or at least a section of it. The induction heating device is therefore configured to generate a magnetic field by means of an electric current, which is subsequently converted into heat. The electric current can thus also be referred to as heating current. Preferably, a large part or all of the heat introduced by the induction heating device is transferred by means of the magnetic field.Advantageously, this allows heat to be introduced into the hydrogen without requiring the inner container to have additional openings for, for example, thermal and / or electrical lines. This improves the stability and / or tightness of the inner container. Simultaneously, a large area within the inner container can be heated by means of the magnetic field. A vacuum gap is provided between the inner and outer containers. In this case, a "vacuum" is defined in particular as a pressure of less than 300 mbar, preferably less than 10 mbar. -3 mbar, preferably less than 10 -7mbar, to be understood. The hydrogen storage container is thus vacuum-insulated or vacuum-damped. This reduces and / or prevents the unwanted introduction of additional heat into the hydrogen. According to a further embodiment, the inductor is arranged within the gap. The inductor is therefore located within the outer container but outside the inner container, i.e., in the area that is subjected to a vacuum. Advantageously, this allows the inductor to be positioned particularly close to the liquid hydrogen to be heated. According to a further embodiment, the inductor is arranged outside the outer container. The inductor can thus be exposed to the ambient air surrounding the hydrogen storage container. Advantageously, this allows the ambient air to contribute to the thermal cooling of the inductor.The risk of overheating of the inductor can thus be significantly reduced and / or prevented. According to a further embodiment, the inductor is arranged spirally around a central axis of the hydrogen storage container. 26.06.2025 – Claudia Meilinger6 The inductor is therefore constructed in the form of a coil, which extends spirally around the central axis of the hydrogen storage container. The spiral has at least one turn in a circumferential direction around the central axis, while the turn simultaneously extends in an axial direction parallel to the central axis. Preferably, the inductor has a plurality of turns around the central axis. With respect to the axial direction, the inductor can extend along a region of the hydrogen storage container.Preferably, however, the inductor extends axially along as large a region of the hydrogen storage container as possible, for example, along the entire length of a tubular or cylindrical base section of the inner container. The length can be interpreted here as its extent along the central axis. Advantageously, this allows the induction heating device to heat a very large area of ​​the inner container, thereby increasing the contact area with the hydrogen. Furthermore, this can reduce and / or prevent mechanical stresses in the inner container. According to another embodiment, the inductor has loops that extend parallel to a central axis of the hydrogen storage container. The inductor is loop-shaped and / or formed in tracks, which loops and / or tracks extend parallel to the central axis of the hydrogen storage container.The central axis of the hydrogen storage tank can also be referred to as its longitudinal axis. Preferably, the loops and / or tracks extend along the entire length of the base section of the inner container. Consequently, a major extent of the loops and / or tracks extends along the central axis of the hydrogen storage tank. According to a further embodiment, the induction heating element comprises a ferromagnetic material. The induction heating element comprises a material with atoms whose magnetic moments tend to align parallel to each other. The induction heating element can, for example, comprise iron, cobalt, and / or nickel. The induction heating element can also be made entirely or almost entirely of iron, cobalt, and / or nickel. The induction heating element is designed to be magnetized by means of the magnetic field.Furthermore, the induction heating element is configured to generate an electric current when a magnetic field is present. This current flows within the heating element, thereby heating it. The heating element is, in this case, part of the induction heating device. The heating device is thus configured to generate the magnetic field, which subsequently heats the heating element, by means of the inductor and the heating current. The liquid hydrogen can then be heated by heat transfer between the ferromagnetic element and the liquid hydrogen. According to one embodiment, the heating element is designed and arranged in the inner container such that it is located in a liquid zone and a gas zone, which form after the liquid hydrogen has been poured into the interior of the inner container.The induction heating element is designed to form the largest possible contact area with the liquid and, if applicable, gaseous hydrogen. This advantageously allows the liquid and, if applicable, gaseous hydrogen to be heated particularly quickly. The latter helps to avoid or reduce temperature stratification of the gaseous hydrogen within the inner container. According to one embodiment, the induction heating element extends beyond a central axis or half the height of the inner container. The induction heating element can have various shapes; for example, it can be designed as one or more blocks, plates, wires, rods, and / or grids. According to another embodiment, the induction heating element has a plurality of heating wires, heating rods, or heating plates forming a grid.The heating plates can be characterized by being particularly thin-walled compared to two main dimensions. 26.06.2025 – Claudia Meilinger8 The term "lattice shape" can be understood here to mean that the majority of heating wires, heating rods, and / or heating plates are arranged along at least two intersecting directions. For example, the heating wires, heating rods, and / or heating plates can be oriented perpendicular to each other. The lattice shape can be located within a cross-sectional plane that is oriented perpendicular to the central axis and / or longitudinal axis of the hydrogen storage container. Alternatively or additionally, the lattice shape can also be located within a cross-sectional plane that is oriented parallel or obliquely to the central axis and / or longitudinal axis of the hydrogen storage container.The induction heating element can therefore also form a three-dimensional grid, i.e., it can have a plurality of heating wires, heating rods, and / or heating plates extending along at least three intersecting directions. Advantageously, this allows the heat to be introduced simultaneously into as large an area of ​​the hydrogen storage container as possible. This improves the rapid heating of the liquid hydrogen. According to a further embodiment, the induction element has a plurality of heating plates arranged in different vertical planes. The heating plates are preferably arranged parallel to each other. According to a further embodiment, the induction heating element has one or more heating plates, each of which is attached to the inner container only on one side. The respective heating plate can have a rigidly clamped mounting. The heating plate or...The heating plates can be mechanically stiffened. The induction heating element can be screwed and / or welded to the inner wall of the container. According to a further embodiment, the induction heating element has a circular heating plate. Preferably, the heating plate or plates have a flow opening for the liquid hydrogen. 26.06.2025 – Claudia Meilinger9 Preferably, the heating plate or plates have a flow opening for the gaseous hydrogen. In addition to the induction heating elements described above, the inner container can have an induction-heatable layer on its inner wall. For this purpose, the induction-heatable layer can, for example, consist of or be made of iron, cobalt, and / or nickel.Advantageously, this further improves the heat input of the hydrogen storage tanks by providing the largest possible contact surface with the liquid and, if applicable, gaseous hydrogen. Furthermore, a method for operating a hydrogen storage tank for storing liquid hydrogen is proposed. The hydrogen storage tank comprises an inner container enclosing an interior space, an outer container enclosing the inner container, and an induction heating device, wherein a gap is arranged between the inner and outer containers, and wherein the gap is subjected to a vacuum. According to the invention, the inner container is made of an austenitic steel alloy.The method comprises the steps: a) receiving the liquid hydrogen in the inner container, and b) in order to achieve a pressure increase within the inner container, introducing heat into the liquid hydrogen by means of the induction heating device with an induction heating element (22A – 22H) arranged within the inner container and extending radially inwards from the inner container in the hydrogen storage container, dividing the interior of the inner container into several areas. According to a further embodiment, during step b), the induction heating element arranged within the inner container is heated by an inductor of the induction heating device. According to a further embodiment, during step b), the inner container is heated directly by an inductor of the induction heating device.The embodiments and features described for the proposed hydrogen storage tank apply accordingly to the proposed method, and vice versa. 26.06.2025 – Claudia Meilinger 10 The term "one" in this context is not necessarily to be understood as restricting it to exactly one element. Rather, several elements, such as two, three, or more, may also be provided. Likewise, every other counter used here is not to be understood as requiring a precise restriction to exactly the corresponding number of elements. Rather, numerical deviations both upwards and downwards are possible. Further possible implementations of the hydrogen storage tank and / or the method also include combinations of features or embodiments described previously or subsequently with regard to the exemplary embodiments, even if not explicitly mentioned.The person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the hydrogen storage container and / or the method. Further advantageous embodiments of the hydrogen storage container and / or the method are the subject of the dependent claims and the exemplary embodiments of the hydrogen storage container and / or the method described below. The hydrogen storage container and / or the method are further explained below with reference to preferred embodiments and the accompanying figures. Fig. 1 shows a schematic sectional view of one embodiment of a hydrogen storage container; Fig. 2 shows a schematic sectional view of another embodiment of a hydrogen storage container; Fig. 3 shows a schematic sectional view of another embodiment of a hydrogen storage container; Fig.Figure 4 shows a schematic sectional view of another embodiment of a hydrogen storage container; 26.06.2025 – Claudia Meilinger11 Figure 5 shows a schematic sectional view of another embodiment of a hydrogen storage container; Figure 6 shows a schematic sectional view of another embodiment of a hydrogen storage container; Figure 7 shows a schematic sectional view of another embodiment of a hydrogen storage container; Figure 8 shows a schematic sectional view of another embodiment of a hydrogen storage container; Figure 8a shows a schematic sectional view of the embodiment according to Figure 8 along the hydrogen storage container; and Figure 9 shows a schematic block diagram of an embodiment of a method for operating the hydrogen storage container according to Figure 1. In the figures, identical or functionally equivalent elements have been provided with the same reference numerals unless otherwise indicated. The figuresFigure 1 shows a schematic sectional view of an embodiment of a hydrogen storage container 1A. The hydrogen storage container 1A can also be referred to as a storage container or storage tank. The hydrogen storage container 1A is preferably suitable for storing hydrogen H₂ (boiling point: 1 bara: 20.268 K = -252.882 °C). However, the hydrogen storage container 1A can also be used for other cryogenic liquids. Examples of cryogenic fluids or liquids, or simply cryogens, are, in addition to the aforementioned hydrogen H₂, liquid helium He (boiling point 1 bara: 4.222 K = -268.928 °C), liquid nitrogen N₂ (boiling point 1 bara: 77.35 K = -195.80 °C), or liquid oxygen O₂ (boiling point 1 bara: 90.18 K = -182.97 °C). It is assumed that hydrogen (H₂) is used as the cryogen. Therefore, the terms "hydrogen" and "cryogen" can be used interchangeably throughout this text. 26.06.2025 – Claudia Meilinger12 The hydrogen storage container 1A can be a transport container. For example, liquid hydrogen LH2 can be transported with the hydrogen storage container 1A. The hydrogen storage container 1A can be part of a vehicle, in particular a watercraft. In this case, the hydrogen storage container 1A is suitable for mobile applications. However, the hydrogen storage container 1A can also be used in a stationary manner, for example in building technology. The hydrogen storage container 1A is assigned a right-hand orthogonal coordinate system with an x-direction x, a y-direction y, and a z-direction z. Here, the y-direction y is oriented parallel to a gravitational direction g. The x-direction x and the z-direction z are each oriented perpendicular to the gravitational direction g. The sectional view of Fig.Figure 1 is therefore oriented parallel to a symmetry or central axis 2 of the hydrogen storage container 1A. In other words, the sectional view according to Figure 1 lies within a plane that is oriented parallel to the x-direction x and parallel to the y-direction y. The hydrogen storage container 1A is rotationally symmetrical about the central axis 2. The central axis 2 is oriented parallel to the x-direction x. The hydrogen storage container 1A comprises a first container or inner container 3 with an interior space 3a, which is also rotationally symmetrical about the central axis 2. The inner container 3 comprises a tubular or cylindrical base section 4, which is also rotationally symmetrical about the central axis 2. The base section 4 can have a circular or approximately circular cross-section. The end faces of the base section 4 are closed on both sides by means of a cover section 5, 6.The lid sections 5 and 6 are convex. A first lid section 5 and a second lid section 6 are convex in opposite directions, so that the lid sections 5 and 6 are convex outwards with respect to the base section 4. The inner container 3 is fluid-tight, in particular gas-tight. The inner container 3 is made of stainless steel. The inner container 3 is therefore made of an austenitic material. The liquid hydrogen LH2 is contained in the inner container 3. As long as the hydrogen H2 is in the two-phase region, a gas zone 7 with gaseous hydrogen GH2 and a liquid zone 8 with liquid hydrogen LH2 can be provided in the inner container 3. Thus, after filling the inner container 3, the hydrogen H2 can have two phases with different states of matter, namely liquid and gaseous.This means that in the inner container 3 there is a phase boundary 9 between the liquid hydrogen LH2 and the gaseous hydrogen GH2. The gaseous hydrogen GH2 can also be referred to as the gaseous phase. Accordingly, the terms "gaseous hydrogen" and "gaseous phase" can be used interchangeably. The liquid hydrogen LH2 can also be referred to as the liquid phase. Accordingly, the terms "liquid hydrogen" and "liquid phase" can be used interchangeably. The inner container 3 is completely enclosed within a second container or outer container 10. The outer container 10 therefore surrounds the inner container 3. The hydrogen storage container 1A is thus double-walled. The outer container 10 is also rotationally symmetrical about the central axis 2.The outer container 10, like the inner container 3, comprises a tubular or cylindrical base section 11, which is rotationally symmetrical about the central axis 2. The base section 11 can have a circular or approximately circular cross-section. The base section 11 is closed at each end by a cover section 12, 13. In particular, a first cover section 12 and a second cover section 13 are provided. The cover sections 12, 13 are oppositely curved, so that the cover sections 12, 13 are convex outwards with respect to the base section 11. The outer container 10 is fluid-tight, in particular gas-tight. The outer container 10 is also preferably made of stainless steel. A gap 14, which completely surrounds or encloses the inner container 3, is provided between the inner container 3 and the outer container 10. The gap 14 is pressurized with a vacuum.In this context, a "vacuum" is defined in particular as a pressure of less than 300 mbar, preferably less than 10 mbar. -3 mbar, preferably less than 10 -7mbar, to understand. The hydrogen storage tank 1A is thus vacuum-insulated. The fact that the gap 14 completely "encloses" or "encloses" the inner container 3 means that the gap 14 completely surrounds the base section 4 and is also provided between the two first cover sections 5, 12 and between the two second cover sections 6, 13. A thermal insulation element (not shown) is provided in the gap 14, completely enclosing or surrounding the inner container 3. That is, the insulation element encloses both the base section 4 and the cover sections 5, 6 of the inner container 3. The insulation element serves for thermal insulation. The insulation element is multi-layered. That is, the insulation element comprises a multitude of layers.The insulating element can therefore also be referred to as a multilayer insulating element or a multilayer thermal insulation element. In particular, the insulating element is a so-called multilayer insulation (MLI). The outer container 10 borders an environment 15 of the hydrogen storage container 1A. A withdrawal line 16 extends from the liquid zone 8, by means of which liquid hydrogen LH2 can be withdrawn from the hydrogen storage container 1A. The withdrawal line 16 leads to an evaporator 17, by means of which the liquid hydrogen LH2 can be vaporized to gaseous hydrogen GH2. The evaporator 17 can vaporize the liquid hydrogen LH2 electrically or with the aid of a heating medium. A valve 18 can be connected in the withdrawal line 16 between the hydrogen storage container 1A and the evaporator 17. From the evaporator 17, the withdrawal line 16 leads to a consumer 19. The consumer 19 is preferably a fuel cell.In this context, a "fuel cell" is understood to be a galvanic cell that converts the chemical reaction energy of a continuously supplied fuel, in this case gaseous hydrogen GH2, and an oxidizing agent, in this case oxygen, into electrical energy. The vaporizer 17 supplies the gaseous hydrogen GH2 to the consumer 19 at a suitable supply pressure and temperature. The hydrogen storage tank 1A also includes an induction heating device 20A. Heat Q can be introduced into the hydrogen by means of the induction heating device 20A. With the help of the induction heating device 20A, a pressure build-up or pressure increase can be achieved within the inner tank 3, particularly in the gas zone 7. The induction heating device 20A has an inductor 21A.The inductor 21A is located outside the inner container 3. The inductor 21A is configured to carry an electric heating current E. This electric heating current E can be supplied from various energy storage devices. For example, the heating current E can be provided by an electric battery. Alternatively, the heating current E can be supplied directly or indirectly, for example, by using an intermediate electrical storage device (not shown), through the operation of the load 19. The inductor 21A converts at least part of the electric heating current E into a magnetic field H. The induction heating device 20A also includes an induction heating element 22A. The induction heating element 22A is located in the liquid zone 8 and is made of a material that can be magnetized by the magnetic field H.In particular, it is a ferromagnetic material. The induction heating element 22A can, for example, contain or be made of iron, cobalt, and / or nickel. The induction heating element 22A is designed to convert the magnetic field H, at least partially, into an electric current, which can flow within the induction heating element 22A and thereby heat it. The induction heating element 22A extends inwards from the inner container 3 in a radial direction R of the inner container 3 and divides the interior 3a of the inner container into zones 34. The heated induction heating element 22A is further designed to introduce the heat Q into the liquid zone 8 of the liquid hydrogen LH2 and, if applicable, into the gas zone 7 of the gaseous hydrogen GH2. In this way, the induction heating device 20A can transfer the heat Q into the liquid hydrogen LH2 and, if applicable, into the gas zone 7 of the gaseous hydrogen GH2.The gaseous hydrogen GH2 is introduced without the need for additional lines and / or connections to the inner container 3. The magnetic field H generated or produced by the inductor 21A is shown below only schematically as an arrow, illustrating the energy transfer by means of the magnetic field H from the inductor 21A to the ferromagnetic element 22A. The inductor 21A is also shown only schematically in Fig. 1. More detailed embodiments of the inductor 21A are shown and described in Figs. 2 to 5, which are explained below. Similarly, the induction heating element 22A is shown only schematically in Fig. 1. More detailed embodiments of the induction heating element 22A are shown and described in Figs. 6 to 8a.The hydrogen storage container 1A, the extraction line 16, the vaporizer 17, and the valve 18 can form a gas supply device 23, in particular a hydrogen supply device, which is suitable for supplying the consumer 19 with gaseous hydrogen GH2 at the aforementioned supply pressure and supply temperature. The gas supply device 23 can include a control unit 24 which can control the vaporizer 17, the valve 18, and / or the induction heating device 20A. This control can be based on sensor signals from a sensor system 25. The sensor system 25 can, for example, include temperature and / or pressure sensors that are arranged in or on the inner container 3, the extraction line 16, the vaporizer 17, the valve 18, and / or the consumer 19.Particularly in maritime applications, movement of the liquid hydrogen LH2 stored in the hydrogen storage tank 1A caused by sea state must be taken into account. If the hydrogen storage tank 1A is arranged horizontally, as shown in Fig. 1, the inertia of the liquid hydrogen LH2 and the curvature of the hydrogen storage tank 1A resulting from its horizontal installation promote extensive sloshing of the liquid hydrogen LH2 both on its cylindrical outer wall and at its ends. This sloshing leads to the cooling of the gaseous hydrogen GH2 above the liquid hydrogen LH2 and thus to an abrupt pressure drop of the gas cushion of gaseous hydrogen GH2 that forms above the liquid hydrogen LH2. Depending on the current sea state, this can have adverse effects on the operating components of the 26.06.2025 – Claudia Meilinger17 Consumer 19 may have insufficient supply pressure, which could lead to unstable operation of consumer 19. According to internal findings, a liquid-cooled and liquid-bearing pump could be used to pump the liquid hydrogen LH2 in order to provide the necessary supply pressure for consumer 19. However, such a pump has moving parts. Furthermore, intermittent operation of the pump could lead to bubble formation in the liquid hydrogen LH2 due to heating. This could cause the pump to malfunction. Alternatively, the liquid hydrogen LH2 could first be vaporized and then compressed to the required supply pressure. However, this is energy-inefficient. The hydrogen storage tank 1A could also be operated directly at the supply pressure.In this case, an equilibrium is established in the hydrogen storage container 1A between the liquid zone 8 and the gas zone 7 layered above it. However, due to the low surface tension of liquid hydrogen LH2, movement of the hydrogen storage container 1A causes the liquid hydrogen LH2 and the gaseous hydrogen GH2 to mix, with the liquid hydrogen LH2 cooling the warmer gaseous hydrogen GH2. Maintaining the supply pressure is then impossible until an equilibrium is again established between the temperatures of the liquid hydrogen LH2 and the gaseous hydrogen GH2. The induction heating device 20A allows the liquid phase LH2 and, if necessary, the gas phase GH2 to be heated particularly quickly and precisely. This enables the supply pressure, especially that of the gas phase GH2, to be adjusted very quickly and accurately.This allows the equilibrium between the temperature of the liquid hydrogen LH2 and that of the gaseous hydrogen GH2 to be set very quickly and precisely. Furthermore, temperature stratification of the hydrogen within the liquid phase LH2 and, if applicable, within the gaseous phase GH2 inside the inner container 3 can be counteracted. The induction heating element 22A, which extends radially inwards into the interior space 3a of the inner container 3 and divides the interior space 3a into areas, prevents or reduces sloshing of the liquid hydrogen LH2, thereby facilitating the maintenance of the supply pressure. The induction heating element 22A can have a flow opening for the liquid hydrogen LH2 (not shown in Fig. 1).This is preferably located in a lower section of the induction heating element 22A to allow complete emptying of the hydrogen from the inner container 3, particularly if the lower section of the induction element 22A completely obstructs the cross-section of the inner container. Fig. 2 shows a schematic sectional view of another embodiment of a hydrogen storage container 1B. The preceding descriptions of the hydrogen storage container 1A also apply to the hydrogen storage container 1B. Therefore, only the differences between the hydrogen storage container 1B and the hydrogen storage container 1A will be discussed below. In the hydrogen storage container 1B, an inductor 21B of an induction heating device 20B is designed as a coil which is arranged spirally around the central axis 2.The inductor 21B is therefore a spiral that extends circumferentially around the central axis 2 and simultaneously axially along the central axis 2. The spiral thus extends along the x-direction x. The representation of the inductor 21B in Fig. 2 is only schematic, particularly with regard to the number of turns. In fact, the number of turns of the inductor 21B is arbitrary. The inductor 21B extends over a large area of ​​the inner container 3, specifically along the entire base section 4 of the inner container 3. The electric heating current E is supplied to the inductor 21B via a first supply line 26 and a second supply line 27. The inductor 21B is arranged outside the outer container 10. This allows the inductor 21B to be cooled by the ambient air 15, thus preventing overheating.An induction heating element 22B, which is part of the induction heating device 20B, is arranged within the inner container 3. The induction heating element 22B is shown here only as a black box 22B and can have one of the embodiments according to the invention. Fig. 3 shows a schematic sectional view of another embodiment of a hydrogen storage container 1C. The preceding descriptions of the hydrogen storage container 1B apply to the hydrogen storage container 1C. Therefore, only the differences between the hydrogen storage container 1C and the hydrogen storage container 1B will be discussed below. In the hydrogen storage container 1C, an inductor 21C of an induction heating device 20C is arranged outside the inner container 3, but inside the outer container 10, i.e., within the gap 14.The outer container 10 has a first opening 28 through which the first supply line 26 passes. The outer container 10 also has a second opening 29 through which the second supply line 27 passes. The first opening 28 and the second opening 29 can each also be referred to as nozzles. Alternatively, the first opening 26 and the second opening 27 can also be configured as a single opening. The arrangement of the inductor 21C within the gap 14 results in a spatial proximity between the inductor 21C and an induction heating element 22C, which is arranged within the inner container 3. This improves, and in particular increases the efficiency of, the energy transfer via the magnetic field H. The induction heating element 22C is shown here only as a black box 22B and can have one of the embodiments according to the invention. The Fig.Figure 4 shows a schematic sectional view of another embodiment of a hydrogen storage container 1D. The preceding descriptions of the hydrogen storage container 1A apply to the hydrogen storage container 1D. Therefore, only the differences between the hydrogen storage container 1D and the hydrogen storage container 1A will be discussed below. 26.06.2025 – Claudia Meilinger 20 In the hydrogen storage container 1D, an inductor 21D of an induction heating device 20D has one or more loops 30, which preferably extend parallel to the central axis 2 of the hydrogen storage container 1D, i.e., parallel to the x-direction x. The central axis 2 can also be referred to as a longitudinal axis. The loops 30 of the inductor 21D preferably extend along the base section 4 of the inner container 3.However, it is also possible for the loops 30 to extend along a different direction, for example, circumferentially around the central axis 2 or obliquely to the central axis 2. The inductor 21D is shown here only schematically, particularly with regard to the number of loops 30. In fact, the number of loops 30 of the inductor 21D is arbitrary. The electric heating current E is supplied to the inductor 21D via supply lines 26, 27. The inductor 21D is arranged outside the outer container 10. This allows the inductor 21D to be cooled by the ambient air of the surroundings 15, thus preventing overheating. An induction heating element 22D, which is part of the induction heating device 20D, is arranged inside the inner container 3. The induction heating element 22D is shown here only as a black box 22D and can have one of the embodiments according to the invention. The Fig.Figure 5 shows a schematic sectional view of another embodiment of a hydrogen storage container 1E. The preceding descriptions of the hydrogen storage container 1D also apply to the hydrogen storage container 1E. Therefore, the following discussion will focus solely on the differences between the hydrogen storage container 1E and the hydrogen storage container 1D. In the hydrogen storage container 1E, an inductor 21E of an induction heating device 20E is arranged within the gap 14, i.e., outside the inner container 3 and inside the outer container 10. The outer container 10 has at least one opening 28 for this purpose, through which a first supply line 26 and a second supply line 27 are routed. The arrangement of the inductor 21E within the gap 14 results in close proximity between the inductor 21E and an induction heating element 22E, which is arranged inside the inner container 3.This improves, and in particular increases the efficiency of, energy transfer via the magnetic field H. The induction heating element 22E is shown here only as a black box 22E and can have one of the embodiments according to the invention. Fig. 6 shows a schematic sectional view of another embodiment of a hydrogen storage container 1F. The sectional view is oriented perpendicular to the central axis 2. In other words, the sectional view lies within a plane that is oriented parallel to the y-direction y and parallel to the z-direction z. The preceding descriptions of the hydrogen storage containers 1A to 1E apply to the hydrogen storage container 1F. Therefore, only the differences between the hydrogen storage container 1F and the hydrogen storage containers 1A to 1E will be discussed below. Fig.Figure 6 shows an induction heating element 22F as a plurality of heating wires, heating rods, and / or heating plates 31 extending inwards from the inner container 3 in a radial direction and dividing the interior of the inner container 3 into several areas. The plurality of heating wires, heating rods, and / or heating plates 31 are arranged along at least two overlapping directions. In this case, the heating wires, heating rods, and / or heating plates 31 run parallel to both the z-direction and the y-direction. However, the heating wires, heating rods, and / or heating plates 31 could also extend along two other, distinct directions. The induction heating element 22F thus forms a two-dimensional grid.By means of the multiple heating wires, heating rods, and / or heating plates 31, the movement of the liquid hydrogen LH2 (not shown) from a first region to a second region adjacent to the central axis 2, but different from the first region, is made more difficult. This counteracts the so-called sloshing effect. 26.06.2025 – Claudia Meilinger 22 It is also possible that the induction heating element 22F is designed as a three-dimensional grid. In this case, for example, further heating wires, heating rods, and / or heating plates 31 could also extend parallel to the x-direction. In this way, the liquid hydrogen LH2 (not shown) can be heated over a particularly large area and thus particularly quickly and / or precisely. In addition, sloshing along the central axis, i.e., in the x-direction, as well as in the z-direction, can be prevented or reduced. The Fig.Figure 7 shows a schematic sectional view of another embodiment of a hydrogen storage container 1G. The preceding descriptions of the hydrogen storage container 1F also apply to the hydrogen storage container 1G. Therefore, only the differences between the hydrogen storage container 1G and the hydrogen storage container 1F will be discussed below. In the hydrogen storage container 1G, an induction heating element 22G has at least one, but preferably three, heating plates 32, which extend inwards from the inner container 3 in a radial direction R of the inner container 3 and divide the interior of the inner container 3 into several areas 34. Each of the at least one heating plate 32 rests against an inner wall 33 of the inner container 3. For example, each of the at least one heating plate 32 can be screwed to the inner container 3 for this purpose.Each of the at least one heating plate 32 extends inwards along a radial direction R, i.e., in the direction of the central axis 2. Each of the at least one heating plate 32 is therefore supported on one side, in particular, it is firmly clamped. Each of the at least one heating plate 32 can extend to the central axis 2, but this is not necessary. Each of the at least one heating plate 32 divides the inner container 3 into a plurality of regions 34, of which only one is designated with a reference numeral in Fig. 7. By means of the at least one heating plate 32, movement of the liquid hydrogen LH2 (not shown) from a first region 34 to an adjacent second region 34, which is different from the first region 34, is made more difficult. This counteracts the so-called sloshing effect. In contrast to the arrangement shown in Fig.In the embodiment shown in Figure 7, additional heating plates 32 can also be provided, which are located in the gas zone 7 of the inner container 3 after the liquid hydrogen LH2 has been filled. This counteracts temperature stratification of the gaseous hydrogen GH2 in the gas zone 7. In contrast to the illustrated embodiment, a heating plate 32 can also extend beyond the central axis (2). Figures 8 and 8a show another embodiment of a hydrogen storage container 1H. Figure 8 shows a cross-section through the hydrogen storage container 1H perpendicular to the central axis 2, and Figure 8a shows a longitudinal section through the hydrogen storage container in the plane of the central axis 2. The preceding descriptions of the hydrogen storage container 1F also apply to the hydrogen storage container 1H. Therefore, the following discussion will focus solely on the differences between the hydrogen storage container 1H and the hydrogen storage container 1F.The hydrogen storage container 1H has an induction heating element 22H with a circular heating plate 22H, which extends inwards from the inner container 3 in a radial direction R of the inner container 3 and divides the interior 3a of the inner container 3 into regions 34, as can be seen in Fig. 8a. The heating plate 22H has a flow opening 35 for the gaseous hydrogen GH2 and a flow opening 36 for the liquid hydrogen LH2 and, apart from these openings 35, 36, extends over the entire cross-section of the interior 3a of the inner container 3. The heating plate 22H is preferably welded and / or bolted to the inner container 3 (not shown). The induction heating element 22H can have several of the heating plates 22H described above, which are arranged at a distance from each other in the direction of the central axis 2, i.e., in the x-direction, and in particular parallel to each other. 26.06.2025 – Claudia Meilinger24 By means of the induction heating element 22H, the movement of the liquid hydrogen LH2 from a first region 34 to a second region 34 adjacent to the central axis 2 and different from the first region 34 is made more difficult. This counteracts the so-called sloshing effect. In addition to the embodiments of an induction heating element 22A to 22H described above, the hydrogen storage container 1A - 1H can have an induction heating element (not shown) which is attached as a layer to the inner wall 33 of the inner container 3. Fig. 9 shows a schematic block diagram of an embodiment of a method for operating the hydrogen storage container 1A to 1H. In the method, the hydrogen storage container 1A to 1H is filled with the liquid hydrogen LH2 in a step S1.During step S1, a fill level of the hydrogen storage container 1A to 1H, in particular the inner container 3, with the liquid hydrogen LH2 of more than 90%, preferably more than 95%, further preferably more than 96%, further preferably more than 97%, further preferably more than 98%, further preferably more than 99%, and further preferably more than 100% can be achieved. This means, in particular, that the hydrogen storage container 1A to 1H, in particular the inner container 3, is filled with the liquid hydrogen LH2 in such a way that no gas zone 7 forms in the inner container 3. In step S2, heat Q is introduced into the liquid hydrogen LH2, thereby causing a pressure increase within the hydrogen storage container 1A to 1H. Step S2 can also be referred to as conditioning, conditioning step, or conditioning process. The heat Q is introduced using the induction heating element 20A to 20H.Although the present invention has been described with reference to exemplary embodiments, it can be modified in many ways. 26.06.2025 – Claudia Meilinger 25 Reference numerals used 1A Hydrogen storage container 1B Hydrogen storage container 1C Hydrogen storage container 1D Hydrogen storage container 1E Hydrogen storage container 1F Hydrogen storage container 1G Hydrogen storage container 1H Hydrogen storage container 2 Central axis 3 Inner container 3a Interior 4 Base section 5 Cover section 6 Cover section. 7 Gaszone 8 Liquid zone 9 Phase boundary 10 Outer container 11 Base section 12 Lid section 13 Lid section 14 Spalt 15 Environment 16 Extraction line 17 Evaporator 18 Ventil19 Consumers 20A Induction heating device 20B Induction heating device 20C Induction heating device 20D Induction heating device 20E Induction heating device 21A Inductor 26.06.2025 – Claudia Meilinger 26 21B Inductor 21C Inductor 21D Inductor 21E Inductor 22A Induction heating element 22B Induction heating element 22C Induction heating element 22D Induction heating element 22E Induction heating element 22F Induction heating element 22G Induction heating element 22H Induction heating element 23 Gas supply device 24 Control and regulation unit 25 Sensors 26 Supply line 27 Supply line 28 Opening 29 Opening 30 Loop 31 Heating wire 32 Heating plate 33 Inner container inner wall 34 Area 35 Flow opening 36 Flow opening E Heating current g Gravity direction GH2 Gaseous hydrogen / gaseous phase H Magnetic field LH2 Liquid hydrogen / liquid phase Q Wärme R Radial direction 26.06.2025 – Claudia Meilinger 27S1 Step S2 Step x x-direction y y-direction z z-direction

Claims

26. 06.2025 – Claudia Meilinger28 Patent Claims 1.Hydrogen storage container (1A – 1H) for storing liquid hydrogen (LH2), comprising an inner container (3) enclosing an interior space (?) for receiving the liquid hydrogen (LH2), an outer container (10) enclosing the inner container (3), wherein a gap (14) is arranged between the inner container (3) and the outer container (10), and wherein the gap (14) is subjected to a vacuum, and an induction heating device (20A – 20E) for introducing heat (Q) into the liquid hydrogen (H2) with an induction heating element (22A – 22H) arranged within the inner container (3), characterized in that the inner container (3) is made of an austenitic steel alloy and the induction heating element (22A – 22H) extends inwards from the inner container (3) in a radial direction (R) of the inner container (3) and heats the interior space (3a) of the The inner container is divided into several sections (34). 2.

1. Hydrogen storage container according to claim 1, wherein the induction heating element (22A – 22H) comprises a ferromagnetic material.

2. Hydrogen storage container according to claim 1 or 2, wherein the induction heating element (22A – 22H) is configured and arranged in the inner container (3) such that it is located in a liquid zone (8) containing the liquid hydrogen (LH2) and in a gas zone (7) containing gaseous hydrogen (GH2), which form after the liquid hydrogen is added.

3. Hydrogen storage container according to any one of claims 1 – 3, wherein the induction heating element (22A-22H) extends beyond a central axis (2) or half the height of the inner container (3).

4. Hydrogen storage container according to claims 1 – 4, wherein the induction heating element (22A-22H) is configured in the form of one or more blocks, plates, wires, rods and / or grids. June 26, 2025 – Claudia Meilinger 29 6. Hydrogen storage container according to any one of claims 1–5, wherein the induction heating element (22H) comprises a plurality of heating plates (22H) arranged in different vertical planes (x,y).

7. Hydrogen storage container according to any one of claims 1–6, wherein the induction heating element (22G) comprises a circular heating plate (22G).

8. Hydrogen storage container according to claim 7, wherein the heating plate (22G) comprises a flow opening (36) for liquid hydrogen (LH2).

9. Hydrogen storage container according to claim 7 or 8, wherein the heating plate (22G) comprises a flow opening (35) for gaseous hydrogen (GH2).

10. Hydrogen storage container according to any one of claims 1–6, wherein the induction heating element (22F) comprises a plurality of heating wires, heating rods, or heating plates (31) arranged in a grid. 11.Hydrogen storage container according to any one of claims 1-10, wherein the induction heating device (20A-20E) comprises an inductor (21A-21E) arranged outside the inner container (3), which is arranged within the gap (14) or outside the outer container (10).

12. Hydrogen storage container according to claim 10, wherein the inductor (21D, 21E) comprises loops (30) which extend parallel to a central axis (2) of the hydrogen storage container (1). 13.Method for operating a hydrogen storage container (1) for storing liquid hydrogen (LH2), wherein the hydrogen storage container (1) comprises an inner container (3) enclosing an interior space (3a), an outer container (10) enclosing the inner container (3), and an induction heating device (20A – 20H), wherein a gap (14) is arranged between the inner container (3) and the outer container (10), and wherein the gap (14) is subjected to a vacuum, and wherein the inner container (3) is made of an austenitic steel alloy, comprising the following steps: 26.06.2025 – Claudia Meilinger30 a) Receiving (S1) the liquid hydrogen (LH2) into the inner container (3), and, b) in order to achieve a pressure increase inside the inner container (3), introducing (S2) heat (Q) into the liquid hydrogen (LH2) by means of the induction heating device (20A – 20H) with an induction heating element (22A – 22H) which is arranged inside the inner container (3) and extends inwards from the inner container (3) in a radial direction (R) of the hydrogen storage container (1) and divides the interior (3a) of the inner container into several areas (34).

14. Method according to claim 13, wherein during step b) the induction heating element (22A – 22H) arranged inside the inner container (3) is heated by an inductor (21A – 21E) of the induction heating device (20A – 20E).

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