Storage container

Abstract

A storage container (1) for storing a cryogenic agent (H2), comprising an inner container (4) for containing the cryogenic agent (H2), an outer container (3) surrounding the inner container (4), and a heating device (14) for establishing a pressure within the inner container (4) by introducing heat (Q) into the cryogenic agent (H2) wherein the heating device (14) has a length compensator (35) arranged to compensate for a thermally dependent length change ([Delta] I) of the inner container (4).

Description

[0001] The invention relates to a storage container for storing a cryogen.

[0002] According to internal operating knowledge, a storage container for liquid hydrogen may have a heating device which makes it possible to establish a predetermined pressure inside the storage container. Such a storage container is essentially cylindrical or barrel-shaped and comprises an inner container for containing hydrogen and an outer container surrounding the inner container. A vacuum chamber is provided between the inner container and the outer container to which a vacuum is applied.

[0003] For example, in order to replace the heating device, the heating device is introduced from the surrounding of the storage container through the vacuum chamber into the inner container. Removal or installation of the heating device must be possible without breaking the vacuum. Furthermore, thermally relevant length changes of the inner container, for example when a cryogenic agent is filled into the inner container which can be fixedly connected to the outer container, should not lead to any mechanical stresses in the outer container, the inner container and / or the heating device.

[0004] Against this background, it is an object of the present invention to provide an improved storage container.

[0005] Therefore, a storage container for storing a cryogenic agent is proposed. The storage container comprises an inner container for accommodating the cryogenic agent, an outer container surrounding the inner container, and a heating device for building up pressure in the inner container by introducing heat into the cryogenic agent, wherein the heating device has a length compensator which is arranged to compensate for thermally related length changes of the inner container.

[0006] Due to the provision of the length compensator, thermally related length changes of the inner container can be compensated in such a way that no stress is exerted on the heating device, the inner container and / or the outer container when the inner container is filled with cryogen due to thermally related contractions of the inner container.

[0007] In particular, the length compensator is arranged to compensate for thermally related length changes of the inner container in the longitudinal direction of the storage container. In addition, length changes in the radial direction of the storage container can also be compensated. However, this is optional.

[0008] The cryogen is preferably hydrogen. Therefore, the terms "cryogen" and "hydrogen" can be interchanged at will. However, the cryogen can also be basically any other cryogen. In addition to the above-mentioned hydrogen, examples of cryogenic liquids, cryogenic fluids or liquids or simply cryogens are liquid helium, liquid nitrogen or liquid oxygen. Therefore, the term "cryogen" refers in particular to a liquid. Therefore, the cryogen can also be called a cryogenic liquid.

[0009] The cryogen can evaporate, thereby converting to a gas phase. After evaporation, the cryogen is a gas, or can be referred to as a gaseous or evaporated cryogen. Therefore, the term "cryogen" can include a gas phase and a liquid phase. As mentioned above, the liquid phase can also be referred to as a cryogenic liquid. In this case, the term "evaporated cryogen" preferably refers only to the gas phase of the cryogen.

[0010] After or during the filling of the storage container with the cryogen, a gas zone and a liquid zone located below it are formed in the storage container, in particular in the inner container of the storage container. A phase boundary is provided between the gas zone and the liquid zone. The heating device is arranged in particular at least in sections in the inner container, in particular in the liquid zone.

[0011] Therefore, after being filled into the storage container, the cryogenic agent preferably has two phases with different aggregation states, namely, a liquid state and a gaseous state. The liquid phase can be converted into a gaseous phase and vice versa. The liquid phase can be referred to as a liquid phase. The gaseous phase can be referred to as a gaseous phase. The storage container can also be filled with a pure liquid.

[0012] The pressure in the storage container is preferably about 3.5 bar. In particular, the pressure in the storage container is constant. The storage container is particularly suitable for supplying the cryogenic agent in the gaseous or liquid phase to the consumer at a suitable supply pressure and a suitable temperature. The consumer can be a fuel cell. In this case, a "fuel cell" is to be understood in particular as a primary cell, which converts the chemical reaction energy of a continuously supplied fuel (in this case hydrogen) and an oxidant (in this case oxygen) into electrical energy.

[0013] The cryogenic agent is supplied to the consumer itself in gaseous form. That is, when the gas phase is supplied directly from the storage container, the cryogenic agent is completely evaporated or heated before or upstream of the consumer. For example, the cryogenic agent is supplied to the consumer at a supply pressure of 1 to 2.5 bar and a temperature of +10° C. to +25° C. However, the supply pressure can also be as high as 6 bar.

[0014] Preferably, the storage container is assigned an axis of symmetry or a central axis, with respect to which the storage container is essentially rotationally symmetrical. Thus, the storage container can have a circular or annular cross section. However, in contrast thereto, the cross section of the storage container can also be egg-shaped or oval. In particular, the inner container and the outer container are also designed in each case rotationally symmetrically with respect to the central axis.

[0015] The inner container and the outer container each comprise a tubular base configured rotationally symmetrically with respect to the central axis. In each case, the end sides of the inner container and the outer container are fluid-tightly closed by a cover. The inner container and the outer container are in particular fluid-tight. The inner container and the outer container can be made, for example, of a metal material, in particular stainless steel. The inner container is completely arranged in the outer container. This means in particular that the outer container completely surrounds the inner container.

[0016] The heating device can be introduced from the periphery of the storage container through the outer container and the inner container into the inner container, in particular into the liquid region of the inner container. For this purpose, the heating device can, for example, be introduced through the corresponding covers of the inner container and the outer container. In particular, the heating device is placed below the phase boundary in the liquid region so that the heating direction is always surrounded or flushed by the liquid phase of the cryogenic agent.

[0017] The heating device is particularly configured to introduce heat directly into the liquid phase of the cryogenic agent. For introducing heat, the heating device preferably comprises a heating unit, which comprises a heating element carried by a carrier element. By introducing heat into the cryogenic agent, the cryogenic agent at least partially evaporates, whereby a pressure build-up can be achieved in the storage container, in particular in the inner container.

[0018] The storage container preferably has a pressure sensor for measuring the internal pressure of the inner container. Thus, the pressure in the inner container can be monitored.

[0019] Preferably, the storage container has a control device connected to the pressure sensor and the heating device. Thus, the pressure in the inner container can be regulated.

[0020] The heating device is preferably assigned an axis of symmetry or a central axis, with respect to which the heating device is substantially rotationally symmetrical. The cross section of the heating device can be circular or cylindrical. However, this does not exclude that the cross section of the heating device can be at least partially egg-shaped or elliptical. This means in particular that the heating device can have an egg-shaped cross section.

[0021] The central axis of the heating device is located below the central axis of the storage container relative to the direction of gravity. Therefore, the central axis of the storage container is arranged above the central axis of the heating device relative to the direction of gravity. The central axis of the heating device and the central axis of the storage container are parallel to each other and spaced apart.

[0022] When the cryogen is filled into the inner container, the inner container, which can be fixedly connected to the outer container, shrinks in the longitudinal direction due to the heat. In this case, the longitudinal direction is oriented parallel to the central axis of the storage container. As the inner container shrinks, it moves a length change relative to the outer container. The length change can be, for example, a few millimeters. This length change can be compensated by a length compensator.

[0023] In this case, "compensation" means that the length compensator is pushed together or pulled apart so that heat-related stresses are introduced neither into the heating device nor into the inner or outer container. The length compensator is thus telescopic. In this case, the term "telescopic" is to be understood in particular as meaning that the length compensator can be pushed together or folded together or pulled apart or unfolded at least in sections. The length compensator can thus be elastically deformed, in particular spring-elastically deformed.

[0024] According to one embodiment, the storage container further comprises a vacuum chamber arranged between the inner container and the outer container, wherein the heating device has a housing which passes through the vacuum chamber until it is introduced into the inner container, and wherein the interior space of the heating device surrounded by the housing is fluidically separated from the vacuum chamber.

[0025] As mentioned above, the inner container is completely surrounded or encapsulated by the outer container. A gap in the form of a vacuum chamber is provided between the inner container and the outer container. The vacuum chamber is evacuated. In this case, "vacuum" means in particular less than 300 mbar, preferably less than 10 -3 mbar, more preferably less than 10 -7 mbar pressure. The storage container is thus vacuum-insulated or vacuum-isolated. The outer shell is preferably introduced into the inner container below the phase boundary so that the outer shell is flushed with the cryogenic agent. The outer shell is preferably tubular. The above-mentioned heating unit of the heating device is arranged in the outer shell, which heating unit is configured to introduce heat into the cryogenic agent. In this case, the fact that the inner space surrounded by the outer shell is "fluidically" separated from the vacuum chamber is to be understood in particular as meaning that there is no fluid connection between the inner space of the heating device and the vacuum chamber. This means in particular that the inner space of the heating device surrounded by the outer shell is not in fluid communication with the vacuum chamber.

[0026] According to another embodiment, the inner space is filled with a heat conducting medium.

[0027] The heat-conducting medium can be a gas. Therefore, the terms "medium" and "gas" can be interchanged at will. The heat-conducting medium can also be a liquid or include a liquid. The heat-conducting medium can include a liquid phase, a solid phase and a gas phase. The heat-conducting medium can be part of the heating device. With the help of the heat-conducting medium, heat conduction between the heating unit and the housing of the heating device and therefore between the heating unit and the liquid phase of the cryogen is ensured. For example, an inert gas can be used as a suitable gas. The heat-conducting medium or gas can be helium. In particular, the heat-conducting medium must be selected in such a way that the heat-conducting medium does not undergo a phase change over the entire operating temperature range of the storage container. In particular, the heat-conducting medium should not freeze or solidify. Optionally, a phase change of the heat-conducting medium can also be provided during the operation of the heating device. This can be achieved by appropriately selecting the heat-conducting medium. The filling pressure and the heat-conducting medium are preferably selected so that at the lowest and highest temperatures that may occur during the operation of the storage container, there is a difference with the surrounding ambient pressure and the operating pressure of the storage container. The above differences make it possible to reliably detect possible leaks between the liquid zone and the inner space of the shell, between the vacuum chamber and the inner space of the shell and / or between the surrounding and the inner space of the shell. In the case where the cryogen is hydrogen, the heat transfer medium is preferably helium. By using helium as the heat transfer medium, solidification of the heat transfer medium when the storage container is operated with hydrogen can be reliably prevented. For example, any overpressure that allows leakage monitoring is selected as the filling pressure of the inner space of the shell. Preferably, a pressure of 1.1 to 200 bar, in particular 5 to 10 bar, is selected as the filling pressure. Therefore, monitoring of the inner space makes safe leakage monitoring possible so as to meet the requirements of separation of the electrical system and the process system and separation from the surrounding according to relevant regulations.

[0028] According to a further embodiment, the outer shell is fixedly connected to the inner container.

[0029] In particular, the outer shell is connected to the inner container in a materially locked manner. In a materially locked connection, the connection parts are fixed together by atomic or molecular forces. Materially locked connections are inseparable connections that can only be separated by destroying the connection parts and / or the connection parts. For example, they can be connected in a materially locked manner by gluing, soldering, welding or vulcanization. For example, the outer shell is soldered or welded into the inner container. As mentioned above, the inner container has a base, which is connected on the end side by two cover parts. The outer shell is particularly fixedly connected to one of the cover parts. The outer shell can be soldered or welded into a cover part of the inner container.

[0030] According to a further embodiment, the housing passes through the length compensator.

[0031] The length compensator is in particular cylindrical or tubular. The length compensator can be designed rotationally symmetrically with respect to a central axis of the heating device. The length compensator surrounds or encloses the housing circumferentially.

[0032] According to a further embodiment, the length compensator is fixedly connected to the outer container, wherein the housing is fixedly connected to the length compensator.

[0033] In particular, the length compensator is connected to the outer container in a materially locked manner. As described above, the outer container has a base, the end sides of which are closed in each case by a cover. The length compensator is fixedly connected to one of the cover parts. In particular, the length compensator can be brazed or welded to the outer container. The outer shell is also connected to the length compensator in a materially locked manner. For example, the outer shell can be welded or brazed to the length compensator. The outer shell is thus directly connected to the inner container and indirectly or indirectly connected to the outer container via the length compensator. That is, the length compensator is arranged between the outer shell and the outer container.

[0034] According to another embodiment, the length compensator comprises a bellows portion which is expandable and foldable in the longitudinal direction of the storage container for compensating the length in the longitudinal direction.

[0035] In addition to the bellows section, the length compensator also has a first connection part connected to the outer container and a second connection part connected to the housing of the heating device. The bellows section is arranged between the two connection parts. The bellows section is in particular a bellows, and can therefore also be referred to as a bellows. The bellows section is retractable. The bellows section can be made of a metal material, for example.

[0036] According to a further embodiment, the length compensator surrounds an inner space which is fluidically connected to the vacuum chamber.

[0037] This means in particular that the interior of the length compensator is also subjected to the vacuum prevailing in the vacuum chamber. In this case, the fact that the interior of the length compensator is "fluidly" connected to the vacuum chamber is to be understood in particular that the interior of the length compensator is in fluid communication with the vacuum chamber.

[0038] According to a further embodiment, the heating device comprises a heating unit and a connection piece for introducing heat into the cryogen, wherein the heating unit and the connection piece are arranged in a housing.

[0039] In particular, the heating unit has a carrier element as described above, on which a heating element in the form of a heating wire as described above is wound. The heating unit is in particular mounted on the front side of the connecting piece. The heating unit can be fixedly connected to the connecting piece. The heating unit is in particular placed completely inside the inner container, in particular in the liquid region.

[0040] According to a further embodiment, the housing comprises a flange, wherein the connecting element comprises a flange, and wherein the flange of the housing and the flange of the connecting element are connected to one another in a form-fitting manner.

[0041] The form-locking connection is achieved by engaging at least two connection partners with each other. In this case, the flange of the housing and the flange of the connection piece can be screwed together. The flange of the housing and the flange of the connection piece are sealed to each other in a fluid-tight manner. For this purpose, a so-called welding lip seal can be provided, for example.

[0042] According to a further embodiment, the heating unit is arranged completely in the inner container, wherein the connecting piece is introduced from the periphery of the storage container through the vacuum chamber into the inner container.

[0043] The connecting piece comprises the above-mentioned flange, which is arranged on a rod-shaped or bar-shaped base. The end carrying the heating unit is arranged on the base away from the flange. Therefore, the heating unit can be pushed into the inner container by means of the connecting piece.

[0044] According to another embodiment, the housing comprises a port protruding into the surroundings and fluidically connected to the interior space, wherein the port is fluidically closed.

[0045] For example, the heat-conducting medium can be filled into the inner space of the housing through the port. For this purpose, the port can have a suitable valve. With the help of the port, the pressure of the inner space can also be monitored. For this purpose, a sensor, in particular a pressure sensor, can be provided at the port. The port can include a plurality of different sensors, such as a pressure sensor, a temperature sensor, an optical sensor, a sensor suitable for detecting a cryogenic agent and / or a heat-conducting medium, etc.

[0046] According to another embodiment, the connecting element is made of stainless steel, a composite material and / or plastic.

[0047] In particular, the connecting piece is made of a material with poor thermal conductivity. In addition, the connecting piece has an elongated rod-shaped geometry. This reduces the heat conduction through the connecting piece. For example, the connecting piece is made of polytetrafluoroethylene (PTFE). As composite materials, for example, fiber-reinforced plastic materials, in particular epoxy resins, can be used. For example, glass fibers or carbon fibers can be used as reinforcing fibers.

[0048] According to a further embodiment, the heating unit has connecting lines and / or sensor lines which pass through the connecting element.

[0049] For example, the heating unit has two connecting lines for the heating elements. The connecting lines extend from the heating unit through the connecting piece and the flange of the connecting piece to the surroundings. The heating unit can have one or more temperature sensors. As described above, each temperature sensor is assigned a sensor line. The sensor line also extends from the heating unit through the connecting piece to the flange of the connecting piece and from there into the surroundings.

[0050] According to another embodiment, the connecting element is rod-shaped.

[0051] In this context, "rod-shaped" refers to an elongated geometric shape. For example, the connector has a circular cross section. The connector may be hollow. In this context, the connector is a rod with a circular cross section.

[0052] "One" is not necessarily to be understood here as being limited to exactly one element. On the contrary, a plurality of elements, for example two, three or more, may also be provided. All other counting words used here are also not to be understood as necessarily implementing an exact limitation to an exactly corresponding number of elements. On the contrary, upward and downward numerical deviations are possible.

[0053] Other possible implementations of the storage container also include combinations not explicitly mentioned of the features or embodiments described above or below with respect to the embodiments. In this case, those skilled in the art will also add individual aspects as improvements or supplements to the corresponding basic shapes of the storage container.

[0054] Further advantageous embodiments of the storage container are the subject matter of the dependent claims and of the exemplary embodiments of the storage container described below. The storage container is explained in more detail below with reference to preferred embodiments and with reference to the drawings.

[0055] Figure 1 A schematic cross-sectional view of an embodiment of a storage container is shown;

[0056] Figure 2 Shown according to Figure 1 Detail of Figure II.

[0057] Figure 3 Shown according to Figure 1 A schematic diagram of an embodiment of a length compensator for a storage container; and

[0058] Figure 4 Shown according to Figure 1 Schematic diagram of an embodiment of a connector for a storage container.

[0059] In the figures, identical or functionally identical elements are denoted by the same reference numerals unless otherwise indicated.

[0060] Figure 1 A schematic sectional view of an embodiment of a storage container 1 is shown. Figure 2 Shown according to Figure 1 Detailed Figure II. Figure 1 and Figure 2 .

[0061] The storage container 1 may also be referred to as a storage tank. The storage container 1 is suitable for containing liquid hydrogen H2 (boiling point 1 bar: 20.268K = -252.882°C). Therefore, the storage container 1 may also be referred to as a hydrogen storage container or a hydrogen storage tank. However, the storage container 1 may also be used for other cryogenic liquids. In addition to the above-mentioned liquid hydrogen H2, examples of cryogenic fluids or liquids or simply cryogenic agents include liquid helium He (boiling point 1 bar: 4.222K = -268.928°C), liquid nitrogen N2 (boiling point 1 bar: 77.35K = -195.80°C) or liquid oxygen O2 (boiling point at 1 bara: 90.18K = -182.97°C).

[0062] The storage container 1 is suitable for use in or on a vehicle (not shown). For example, the vehicle may be a marine vessel, in particular a ship. The vehicle may be referred to as a marine vehicle. In particular, the vehicle may be a marine passenger ferry. Alternatively, the vehicle may also be a land vehicle. However, in the following, it is assumed that the vehicle is a ship.

[0063] The storage container 1 is designed rotationally symmetrically with respect to the axis of symmetry or the central axis 2. In this case, the central axis 2 can be oriented perpendicularly to the direction of gravity g. That is, the storage container 1 is horizontal or positioned horizontally. Optionally, the central axis 2 can also be oriented parallel to the direction of gravity g. That is, the storage container 1 can also be positioned upright or vertically. The longitudinal direction L of the storage container 1 is oriented along the central axis 2. Figure 1 In the orientation, the longitudinal direction L extends from left to right.

[0064] The storage container 1 comprises an outer container 3 configured rotationally symmetrically with respect to a central axis and an inner container 4 configured rotationally symmetrically with respect to the central axis 2. In this case, the inner container 4 is arranged completely within the outer container 3. The outer container 3 and / or the inner container 4 can be made of stainless steel, for example.

[0065] An at least sectionally gap-shaped vacuum chamber 5 is provided between the outer container 3 and the inner container 4. A negative pressure exists in the vacuum chamber 5 compared to the surroundings 6 of the storage container 1. The surroundings 6 can also be referred to as atmosphere. This means that the terms "surroundings" and "atmosphere" can be interchanged at will.

[0066] An insulating element or insulating element which at least partially or completely fills the vacuum chamber 5 may be arranged in the vacuum chamber 5. The insulating element may have a multilayer insulation layer (English: Multilayer Insulation, MLI) or be constructed as such. Such a multilayer insulation layer comprises a plurality of alternately arranged layers or stacks of perforated and / or embossed aluminum foil as a reflector and glass paper as a spacer between adjacent aluminum foils. The glass paper may be perforated and / or punched.

[0067] The outer container 3 comprises a tubular or cylindrical base 7 which is constructed rotationally symmetrically with respect to the central axis 2. The base 7 is closed at both ends by a cover 8 in each case, however, at Figure 1 Only one of the cover parts 8 is shown in the figure. The cross section of the base part 7 can have a circular or approximately circular geometry. The cover part 8 is curved. The cover part 8 is curved in opposite directions so that the cover part 8 is bent outward relative to the base part 7. The outer container 3 is fluid-tight, in particular gas-tight.

[0068] Like the outer container 3, the inner container 4 comprises a tubular or cylindrical base 9 which is rotationally symmetrical with respect to the central axis 2. In each case, the base 9 is closed on both sides by a cover 10, however, Figure 1 Only one of the covers 10 is shown in the figure. The cross section of the base 9 can have a circular or approximately circular geometry. The cover 10 is curved. In particular, the cover 10 is curved in opposite directions so that the cover 10 is bent outward relative to the base 9. The inner container 4 is fluid-tight, in particular gas-tight.

[0069] Liquid hydrogen H2 is contained in the inner container 4. As long as the hydrogen H2 is in a two-phase region, a gas region 11 having evaporated hydrogen H2 and a liquid region 12 having liquid hydrogen H2 can be provided in the inner container 4. Therefore, after being filled in the inner container 4, the hydrogen H2 has two phases having different aggregation states, namely, a liquid state and a gaseous state. That is, in the inner container 4, a phase boundary 13 is provided between the liquid hydrogen H2 and the gaseous hydrogen H2.

[0070] The storage container 1 includes a heating device 14. The heating device 14 is Figure 2 The heating device 14 is partially shown in FIG. 1 . The heating device 14 is arranged to introduce heat Q into the liquid hydrogen H2. The heating device 14 is electrically operated. Therefore, the heating device 14 can also be referred to as an electric heating device or a heater, in particular an electric heater.

[0071] The heating device 14 protrudes from the surrounding 6 through the covers 8, 10 into the inner container 4, in particular into the liquid region 12. The part of the heating device 14 protruding into the inner container 4 is preferably flushed with liquid hydrogen H2 of the liquid region 12.

[0072] The following technical challenges must be overcome in order to install the heating device 14. Electrical conductors cannot be installed in the vacuum chamber 5, as there is a risk of overheating of the electrical conductors due to the poor heat conduction in the vacuum chamber 5. The electronics of the heating device 14 cannot be installed in the vacuum chamber 5, as there is also a risk of overheating here.

[0073] By introducing the heating device 14 to reduce the insulating effect of the inner container 4, the insulation of the inner container 4 may be damaged, resulting in an increased heat input from the surroundings 6 to the inner container 4. Due to the formation of a gas roll between the cold inner container 4 and the hot surroundings 6, convection can occur.

[0074] If the inner container 4 and the outer container 3 are fixedly connected to each other, it is desirable to compensate for changes in length between the inner container 4 and the outer container 3 during preheating or cooling of the inner container 4 or by temperature changes in the surroundings 6. The heating device 14 should be replaceable without breaking the vacuum. These challenges are solved by the heating device 14.

[0075] The heating device 14 is designed rotationally symmetrically with respect to an axis of symmetry or central axis 15. The central axis 15 can be oriented parallel to the central axis 2. In this case, the central axis 15 is located below the central axis 2 when viewed relative to the direction of gravity g. Furthermore, a radial direction R is assigned to the heating device 14. The radial direction R is oriented perpendicular to the central axis 15 and away from the central axis 15.

[0076] The heating device 14 comprises a fluid-tight housing 16. The housing 16 is tubular, and therefore can also be referred to as an outer tube. The housing 16 is preferably made of a metal material, preferably stainless steel. The housing 16 is preferably made of a material with good thermal conductivity.

[0077] The housing 16 is introduced into the liquid region 12 via the two covers 8, 10. This means that the housing 16 protrudes partly into the surroundings 6 and partly into the inner container 4, in particular into the liquid region 12. The housing 16 can be soldered or welded into the cover 10 of the inner container 4. The housing 16 is not connected to the cover 8 of the outer container 3. The housing 16 can also be made of a copper alloy, an aluminum alloy, glass, glass ceramic or ceramic.

[0078] The housing 16 is constructed rotationally symmetrically with respect to the central axis 15. The cross section of the housing 16 can be circular. Different from this, the cross section of the housing 16 can also be slightly egg-shaped or elliptical. The housing 16 is closed on the circumference. The housing 16 surrounds an inner space 17. The inner space 17 can be referred to as the inner space of the housing 16 or the inner space of the heating device 14. The inner space 17 can also be referred to as a heated inner space. The inner space 17 is filled with a heat-conducting medium. The heat-conducting medium is preferably a gas, in particular helium He. The housing 16 is fluid-tight.

[0079] The housing 16 comprises a tubular base 18 which is constructed rotationally symmetrically with respect to the central axis 15. In addition to the base 18, the housing 16 comprises a flange 19 which protrudes into the surrounding 6. Remote from the flange 19, the housing 16 has a cover (not shown) which closes the housing 16 in a fluid-tight manner. The cover is placed inside the inner container 4.

[0080] Outside the outer container 3, the housing 16 has a connection 20 which can be closed in a fluid-tight manner. For example, with the help of the port 20, the interior space 17 can be filled with helium He. In addition, the port 20 can also be used to monitor the heating device 14. For example, a pressure drop or a pressure increase in the interior space 17 can be detected via the port 20. The port 20 is placed in the surrounding 6 outside the storage container 1.

[0081] In addition to the housing 16, the heating device 14 also has a tubular carrier element 21, which carries a linear heating element 22. The carrier element 21 can also be called a carrier tube. The carrier element 21 is preferably configured rotationally symmetrically with respect to the central axis 15. The carrier element 21 is made of a material with good thermal conductivity. For example, the carrier element 21 is made of a metal material, in particular a copper alloy or an aluminum alloy. However, the carrier element 21 can also be made of glass, glass ceramic or ceramic. The heating element 22 and the carrier element 21 together form a heating unit 23 of the heating device 14.

[0082] The carrier element 21 can be a monolithic component, in particular a material monolithic component. "Monolithic" or "integral" here means that the carrier element 21 is a single component that does not consist of several subcomponents or components. In this case, "monolithic material" particularly means that the carrier element 21 is made completely of the same material. Optionally, the carrier element 21 can also be multi-part or multi-piece. In this case, the carrier element 21 consists of several subcomponents or components.

[0083] The carrier element 21 extends into the inner container 4 in the longitudinal direction L. In this case, the carrier element 21 is preferably arranged completely within the inner container 4. The carrier element 21 is accommodated in the outer shell 16. This means in particular that the carrier element 21 is placed in the inner space 17. Preferably, the carrier element 21 is placed centrally with respect to the center axis 15, so that a gap 24 filled with helium He is provided between the carrier element 21 and the base 18, which extends completely around the carrier element 21.

[0084] The gap 24 can have a gap width of 0.5 to 1 mm. The gap width is selected to be as small and as large as possible so that the carrier element 21 with the heating element 22 can be pushed into the housing 16. The gap 24 is part of the inner space 17. The gap 24 is optional. Optionally, the carrier element 21 can rest against the inner side of the housing 16. This can improve the heat transfer.

[0085] The cylindrical outer side 25 of the carrier element 21 points towards the housing 16. A gap 24 is provided between the outer side 25 and the housing 16. A groove 26 is provided on the outer side 25, which extends around the carrier element 21 in a screw-shaped or spiral manner and accommodates the heating element 22. The heating element 22 is preferably a heating wire wound on the carrier element 21.

[0086] In the case where the carrier element 21 is made of a conductive material, the heating element 22 may have an electrical insulator that electrically insulates the heating element 22 from the carrier element 21. For example, the above-mentioned heating wire may be embedded in magnesium oxide powder, which is encapsulated by a non-conductive metal shell (e.g., a stainless steel shell). Therefore, the term "heating element" may be understood as a metal mineral insulated heating wire. The groove 26 is optional. The heating element 22 may also be wound on the carrier element 21 without the groove 26.

[0087] The cylindrical inner side 27 of the carrier element 21 faces away from the outer side 25. The inner space 27 can be realized by a hole that passes centrally through the carrier element 21. The heating device 14 has at least one temperature sensor 28 with a sensor line 29. The temperature of the heating device 14 can be detected by means of the temperature sensor 28. The temperature sensor 28 comprises a fastening lug 30. As an alternative to the fastening lug 30, other types of fasteners can also be provided, for example in the form of a clamp, a screw, a welding head or a plug.

[0088] The temperature sensor 28 is held or fastened by a fastening element 31. The fastening element 31 is made of a material that conducts heat well, such as a copper alloy or an aluminum alloy. The fastening element 31 is tubular. The fastening element 31 is arranged in the carrier element 21. For example, the fastening element 31 is pressed into the carrier element 21. The fastening element 31 can be an integral component, in particular a material integral component. Optionally, the fastening element 31 can also be multi-part or multi-piece.

[0089] The fastening element 31 is designed rotationally symmetrically with respect to the center axis 15. The fastening element 31 comprises a cylindrical outer side 32 which bears against the inner side 27 of the carrier element 21. The fastening element 31 also comprises a cylindrical inner side 33, which is realized, for example, by a hole arranged in the center of the fastening element 31. Thus, helium He can flow through the fastening element 31.

[0090] For each temperature sensor 28, the fastening element 31 has a receiving hole 34, into which the corresponding temperature sensor 28 is inserted. The receiving hole 34 is arranged at the end of the fastening element 31 and extends into the fastening element 31 in the longitudinal direction L. The receiving hole 34 extends parallel to the center axis 15. The receiving hole 34 can be a blind hole. Viewed in the radial direction R, the receiving hole 34 is located directly below the outer side 32.

[0091] The heating device 14 further comprises a length compensator 35 . Figure 3 A schematic diagram of an embodiment of such a length compensator 35 is shown.

[0092] The length compensator 35 allows length compensation in the longitudinal direction L. The length compensator 35 is designed rotationally symmetrically with respect to the central axis 15 . The housing 16 passes through the length compensator 35 .

[0093] The length compensator 35 has a cylindrical first connection portion 36 fixedly connected to the cover 8 of the outer container 3. For example, the first connection portion 36 is brazed or welded into the cover 8. A second connection portion 37 is arranged next to the first connection portion 36. The second connection portion 37 comprises a circular portion 38 extending around the center axis 15. By means of the circular portion 38, the second connection portion 37 is fixedly connected to the base 18 of the housing 16, for example, brazed or welded to the housing 16.

[0094] The bellows section 39 is arranged between the first connection section 36 and the second connection section 37. The bellows section 39 can be pushed together and pulled apart in the longitudinal direction L to enable length compensation in the longitudinal direction L. The length compensator 35 is preferably a one-piece component, in particular a material one-piece component. The length compensator 35 can be made of metal. The length compensator 35 encloses an inner space 40 which is fluidically connected to the vacuum chamber 5.

[0095] Now return to Figure 1 The inner container 4 fixedly connected to the outer container 3 at the end facing away from the cover 10 shrinks in the longitudinal direction L due to heat during the filling of liquid hydrogen H2. Figure 1 In FIG. 1 , the starting position of the cover 10 of the inner container 4 which has not yet been filled with liquid hydrogen H2 is indicated by a dotted line and reference numeral 10 ′.

[0096] If the inner container 4 is now filled with liquid hydrogen H2, the cover 10 is Figure 1 The length change Δl is shifted to the right in the direction of . The length change Δl can be, for example, a few millimeters. This length change Δl can be compensated by the length compensator 35, in particular the bellows section 39. In this case, "compensation" is understood to mean that the bellows section 39 is pushed together or pulled apart so that thermal stresses are not introduced into the housing 16, the inner container 4 or the outer container 3.

[0097] The heating device 14 further includes a connecting member 41 . Figure 4 A schematic diagram of an embodiment of such a connecting element 41 is shown.

[0098] The connecting member 41 is accommodated in the housing 16. The connecting member 41 comprises a base 42 extending in the longitudinal direction L. An end 43 adjoins the base 42. The connecting member 41 can be connected to the heating unit 23 by means of the end 43. Thus, the connecting member 41 carries the heating unit 23.

[0099] The connecting piece 41 has a flange 44 away from the end 43. The flange 44 is connected by connecting elements 45, 46 ( Figure 1 ) is connected to the flange 19 of the housing 16. The connecting elements 45, 46 can be screws. By means of the connecting elements 45, 46, the flanges 19, 44 can be simply connected to each other and separated from each other again. In order to seal the flanges 19, 44 from each other, a welding lip seal can be provided.

[0100] The sensor line 29 and the connection lines 47, 48 of the heating element 22 pass through the connection piece 41. For this purpose, suitable channels 49, 50, 51 are provided on the flange 44. The connection piece 41 is preferably made of stainless steel. However, the connection piece 41 can also be made of a plastic material.

[0101] Now back to Figure 1 , the storage container 1 can be part of a cryogenic supply system 52, which is suitable for supplying gaseous hydrogen H2 to a consumer 53, in this case preferably a fuel cell, at a defined supply pressure and a defined supply temperature. For example, the hydrogen H2 is supplied to the consumer 53 in gaseous form at a supply pressure of, for example, 1 to 2.5 bar and a temperature of, for example, 0 to +70° C., in particular +10 to +25° C. However, the supply pressure can also be as high as 6 bar.

[0102] The cryogenic supply system 52 may be referred to as a hydrogen supply system. In addition to the storage container 1 , the cryogenic supply system 52 may also include an evaporator (not shown) adapted to evaporate liquid hydrogen H 2 and supply it to the consumer 53 .

[0103] The design of the heating device 14 allows to maintain the insulating effect on the inner container 4 by inserting a material with low thermal conductivity between the surrounding 6 and the inner container 4. For example, the connection 41 can be made of stainless steel or plastic material for this purpose. It allows to separate the connection lines 47, 48 and the related electronics from the vacuum chamber 5 by an additional barrier in the form of the housing 16 between the connection lines 47, 48 and the vacuum chamber 5.

[0104] The heat generated by the resistors in the electrical connections 47, 48 is removed by the selection of a suitable material for the connection 41 between the heating unit 23 and the flange 44. In this case, on the one hand, it must be ensured that the material carries away the heat generated in the connections 47, 48 and, on the other hand, the cold loss to the surrounding 6 is as small as possible.

[0105] Due to possible cold losses, it is advantageous if the connection piece 41 is designed to be slender in order to maintain the insulating effect as much as possible. A suitable material for the connection piece 41 is stainless steel, since it results in a relatively low outward heat conduction, but is sufficient to remove heat from the electrical connection lines 47, 48. However, other materials with poor thermal conductivity, such as plastics or ceramics, can also be used for the connection piece 41.

[0106] By filling the gap 24 with insulating material, for example in the form of mineral wool, convection rolls between the cold inner container 4 and the hot surrounding 6 and the associated cold losses in the inner container 4 can be suppressed.

[0107] The length compensator 35 can compensate for a length change Δl between the inner container 4 and the outer container 3, which may be caused by different preheating or cooling of the inner container 4 and the outer container 3. Compensation of the length change Δl can also be achieved by an additional axial stop, which can be integrated into the heating device 14.

[0108] The heating device 14 is designed to allow easy replacement of the heating unit 23. For this purpose, a flange connection is provided between the flanges 19, 44. In order to be able to achieve 100% gas tightness, welded lip seals are used at the flanges 19, 44. However, other seals are also possible.

[0109] Different heat-conducting media can be used to fill the gap 24 of the heating device 14 , for example helium He. The size of the space between the heating device 14 and the vacuum chamber 5 is variable and can be adapted to the geometry of the heating device 14 .

[0110] Different thermal insulation can be used between the heating device 14 and the surrounding 6. The outer shell 16 forms a separate space between the inner container 4 and the outer container 3. There is no fluid connection to the inner container 4. Different flange seals can be used on the flanges 19, 44.

[0111] Although the invention has been described on the basis of embodiments, it can be modified in many ways.

[0112] Reference numerals used

[0113] 1 Storage container

[0114] 2 Central axis

[0115] 3 Outer container

[0116] 4. Inner container

[0117] 5 Vacuum Chamber

[0118] 6 Around

[0119] 7 Base

[0120] 8 cover

[0121] 9 Base

[0122] 10 cover

[0123] 10' cover

[0124] 11 Gas Zone

[0125] 12 Liquid Area

[0126] 13 Phase Boundary

[0127] 14 Heating device

[0128] 15 Central axis

[0129] 16 Housing

[0130] 17 Internal Space

[0131] 18 base

[0132] 19 Flange

[0133] Port 20

[0134] 21 Carrier element

[0135] 22 Heating element

[0136] 23 Heating unit

[0137] 24 Gap

[0138] 25 Outer side

[0139] 26 grooves

[0140] 27 Inside

[0141] 28 Temperature Sensor

[0142] 29 sensor line

[0143] 30 Fastening lug

[0144] 31 Fastening elements

[0145] 32 Outer side

[0146] 33 Inside

[0147] 34 Receiving hole

[0148] 35 Length compensator

[0149] 36 Connection part

[0150] 37 Connection part

[0151] 38 round part

[0152] 39 Bellows section

[0153] 40 Interior Space

[0154] 41 Connectors

[0155] 42 base

[0156] 43 end

[0157] 44 Flange

[0158] 45 Connecting elements

[0159] 46 Connecting elements

[0160] 47 Connection cable

[0161] 48 Connection cable

[0162] 49 channels

[0163] 50 channels

[0164] 51 channels

[0165] 52 Low temperature supply system

[0166] 53 Electrical appliances

[0167] g direction of gravity

[0168] Helium / medium

[0169] H2 Hydrogen / Cryogenic Agent

[0170] L Vertical

[0171] Q Heat

[0172] R Radial

[0173] Δl length change

Claims

1. A storage container (1) for storing a cryogenic agent (H2), comprising an inner container (4) for containing the cryogenic agent (H2), an outer container (3) surrounding the inner container (4), and a heating device (14) for building up pressure in the inner container (4) by introducing heat (Q) into the cryogenic agent (H2), wherein: The heating device (14) has a length compensator (35) which is designed to compensate for a thermally dependent length change (Δl) of the inner container (4).

2. The storage container according to claim 1, further comprising a vacuum chamber (5) disposed between the inner container (4) and the outer container (3), wherein: The heating device (14) has a housing (16) which passes through the vacuum chamber (5) until it is introduced into the inner container (4), wherein an interior space (17) of the heating device (14) surrounded by the housing (16) is fluidically separated from the vacuum chamber (5).

3. The storage container (1) according to claim 2, wherein: The internal space (17) is filled with a heat-conducting medium (He).

4. The storage container according to claim 2 or 3, wherein: The outer shell (16) is fixedly connected to the inner container (4).

5. The storage container according to any one of claims 2 to 4, wherein: The housing (16) passes through the length compensator (35).

6. The storage container according to any one of claims 2 to 5, wherein: The length compensator (35) is fixedly connected to the outer container (3), and wherein the housing (16) is fixedly connected to the length compensator (35).

7. The storage container according to any one of claims 2 to 6, wherein: The length compensator (35) comprises a bellows portion (39) which can be unfolded and folded along the longitudinal direction (L) of the storage container (1) for compensating the length along the longitudinal direction (L).

8. The storage container according to any one of claims 2 to 7, wherein: The length compensator (35) encloses an inner space (40) which is fluidically connected to the vacuum chamber (5).

9. The storage container according to any one of claims 2 to 8, wherein: The heating device (14) comprises a heating unit (23) and a connecting piece (41) for introducing heat (Q) into the cryogenic agent (H2), wherein the heating unit (23) and the connecting piece (41) are arranged in the housing (16).

10. The storage container according to claim 9, wherein: The housing (16) comprises a flange (19), wherein the connecting element (41) comprises a flange (44), and wherein the flange (19) of the housing (16) and the flange (44) of the connecting element (41) are connected to one another in a form-fitting manner.

11. The storage container according to claim 9 or 10, wherein: The heating unit (23) is completely arranged in the inner container (4), and the connecting piece (41) is introduced from the periphery (6) of the storage container (1) through the vacuum chamber (5) into the inner container (4).

12. The storage container according to any one of claims 9 to 11, wherein: The housing (16) comprises a port (20) protruding into the surrounding (6) and fluidly connected to the interior space (17), and wherein the port (20) is fluidly closed.

13. The storage container according to any one of claims 9 to 12, wherein: The connecting piece (41) is made of stainless steel, composite material and / or plastic.

14. The storage container according to any one of claims 9 to 13, wherein: The heating unit (23) has connection lines (47, 48) and / or sensor lines (29) passing through the connection piece (41).

15. The storage container according to any one of claims 9 to 14, wherein: The connecting member (41) is rod-shaped.

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