Pressure vessel for storing gaseous fuel, and pressure vessel system

Abstract

According to the invention, the technology disclosed here relates to a pressure vessel (10) for storing gaseous fuel, comprising a vessel wall (20) which forms an interior (25) for receiving the gaseous fuel, and a temperature sensor (40), and a separating wall (60) which partially delimits the interior (25) toward the outside, wherein the temperature sensor (40) is detachably fastened to the vessel wall (20) and the separating wall (60) delimits the temperature sensor (40) from the interior (25). According to the invention, the technology disclosed here also relates to a pressure vessel system comprising a plurality of pressure vessels (10), of which at least one is designed as described.

Description

[0001] Pressure vessel for the storage of gaseous fuel and pressure vessel system

[0002] The technology disclosed here relates to a pressure vessel for storing gaseous fuel and an associated pressure vessel system.

[0003] Pressure vessels are typically used to store gaseous fuel such as hydrogen. They can be used in mobile or stationary units, for example. It is often desirable to monitor the temperature inside a pressure vessel. Temperature sensors can be provided for this purpose, with temperature sensors typically positioned to measure the temperature of gaseous fuel within the pressure vessel.

[0004] It is a preferred object of the technology disclosed here to reduce or eliminate at least one disadvantage of a previously known solution or to propose an alternative solution. In particular, it is a preferred object of the technology disclosed here to provide a pressure vessel in which the replacement of a temperature sensor is easier. Further preferred objects can arise from the advantageous effects of the technology disclosed here. The objects are solved by the subject matter of the independent patent claims. The dependent claims represent preferred embodiments. The technology disclosed here relates to a pressure vessel for storing gaseous fuel, comprising (i) a vessel wall forming an interior space for receiving the gaseous fuel, (ii) a temperature sensor, and (iii) a partition wall partially demarcating the interior space from the outside.The temperature sensor is conveniently detachably attached to the container wall and the partition wall conveniently separates the temperature sensor from the interior.

[0005] This design ensures that the temperature sensor does not come into direct contact with the gaseous fuel stored in the pressure vessel. In typical applications, this makes replacing the temperature sensor particularly easy. This offers advantages during the operation and maintenance of a pressure vessel, as it may occasionally be necessary to replace a temperature sensor.

[0006] The container wall typically forms and / or at least substantially defines the interior space, which typically represents a cavity in which the gaseous fuel is stored. The container wall is typically made of steel or a plastic material. In certain designs, a liner can be arranged on the inside of the container wall. This typically serves as a permeation barrier. The interior space is then at least partially delimited on the outside by the liner; nevertheless, the container wall ultimately forms the interior space, since the liner is typically applied directly to the container wall and typically represents only a thin layer.

[0007] The temperature sensor is typically designed to measure the temperature of the gaseous fuel stored in the interior. The temperature sensor typically generates an output signal that can be read and then allows a conclusion to be drawn about the temperature. The temperature sensor is typically a component that is identifiable as such. It can, for example, comprise electrical components such as a temperature-dependent resistor.

[0008] Such electrical components can be exposed or, for example, enclosed by a casing. Such a casing typically lies directly against the electrical components. Such a casing does not constitute a partition wall within the meaning of the technology disclosed here. The temperature sensor can thus be designed, in particular, as a non-destructively disassemblable unit, which can be connected, in particular, via connecting cables.

[0009] The partition wall and the vessel wall, as well as any end piece described below, together typically form a complete enclosure of the interior, possibly apart from deliberately added openings, for example those intended for refueling with gaseous fuel or for removing gaseous fuel. The pressure vessel is then in an operational state because it can store gaseous fuel, be refueled with it, and remove it, for example to operate a fuel cell. The temperature sensor can measure the temperature of the gaseous fuel and is separated from the interior by the partition wall. The partition wall forms a special element that ensures that the temperature sensor does not come into direct contact with the gaseous fuel.

[0010] The detachable attachment of the temperature sensor to the container wall can be direct, but it can also be indirect. For example, the temperature sensor can be attached to a closure piece, as described below, which is then in turn attached to the container wall. Alternatively or additionally, the temperature sensor can be part of a temperature sensor module, which is then attached to the container wall or to the closure piece. With a direct or immediate connection or attachment, there is typically no other element between the aforementioned components.

[0011] According to one embodiment, the temperature sensor is detachably attached independently of the partition wall. This allows the partition wall to remain in a specific location within the pressure vessel and thus also expediently ensures a seal at the corresponding point within the interior to the outside. The temperature sensor can then be removed, and a new temperature sensor, for example, can be installed without otherwise impairing the functionality of the pressure vessel in any way. In particular, this makes it unnecessary to vent the gaseous fuel from the interior or reduce the pressure in order to replace the temperature sensor.

[0012] According to one embodiment, the container wall has an opening, wherein the pressure vessel has a closure piece that closes the opening. Such a closure piece can, for example, be an insert, which is typically referred to as a boss. Such a closure piece can, for example, also contain other elements such as supply lines, outlet lines or pressure sensors. The closure piece can, in particular, be screwed into the opening. For this purpose, the opening and closure piece can have corresponding threads. However, other types of fastening are also possible. According to one embodiment, the partition wall can be fastened directly to the closure piece. This means that the partition wall remains on the closure piece and thus also continues to delimit the interior space as long as the closure piece is not removed.

[0013] The partition wall can, in particular, be attached to the end piece in such a way that it cannot be removed without damage. For example, the partition wall can be welded, soldered, or glued to the end piece. Such attachments are typically not designed to be released by simply releasing a frictional or positive fit. The partition wall thus remains attached to the end piece as long as no particular force is applied. In particular, the partition wall and the end piece can be constructed as a single piece and / or bonded to one another.

[0014] According to one embodiment, the temperature sensor can be detachably attached to the end piece. For example, this can be done by plugging or screwing. This typically involves a fastening that can be removed by loosening a force-locking or form-locking connection. This allows for easy replacement of the temperature sensor. The partition wall nevertheless ensures that the interior is not connected to the environment.

[0015] According to one embodiment, the pressure vessel comprises a temperature sensor module, wherein the temperature sensor module comprises the temperature sensor and the partition and is detachably fastened in the end piece. This represents an alternative to a fixed attachment of the partition to the end piece. This is particularly advantageous for retrofitting solutions, since an installation space already available for the temperature sensor can be used to install the temperature sensor module. The temperature sensor can, in particular, be detachably fastened in the temperature sensor module. This allows the temperature sensor to be replaced separately, while the rest of the temperature sensor module, in particular the partition, remains installed.

[0016] According to one embodiment, the partition is attached directly to the container wall. This represents, in particular, an alternative to attaching the partition to the aforementioned end piece.

[0017] For example, with such a design, an end piece can be omitted.

[0018] In particular, the partition can be attached to the container wall in such a way that it cannot be removed without causing damage. This ensures that the interior is sealed off from the outside regardless of the presence of the temperature sensor. The temperature sensor can, in particular, be removably attached directly to the container wall. This can be done, for example, by plugging or screwing. This allows for easy attachment and removal, for example, for replacement.

[0019] According to one embodiment, the pressure vessel comprises a temperature sensor module, wherein the temperature sensor module comprises the temperature sensor and the partition wall and is detachably fastened in the vessel wall. This allows a detachable fastening of the temperature sensor, just as with the temperature sensor module described above, which is fastened to the connecting piece. In particular, it can be provided that the temperature sensor is detachably fastened to the temperature sensor module. A detachable fastening can be understood, in particular, as a non-destructively detachable fastening. In particular, this can mean that the temperature sensor is screwed in or attached by means of a detachable, positive-locking fastening.

[0020] In particular, it can be provided that the partition wall protrudes a maximum of 10 cm into the interior, starting from an immediately adjacent section of the pressure vessel. This can therefore be a projection that protrudes into the interior. This preferably has a maximum length of no more than 10 cm. Alternatively, values ​​of no more than 5 cm, no more than 8 cm, or no more than 15 cm could also be used. This minimizes any reduction in the space available for storing gaseous fuel. The partition wall can, for example, have an elongated shape, for example with a completely or at least partially round cross-section that tapers to a point.

[0021] In particular, the partition wall can have a maximum thickness of 2 mm. This has proven particularly advantageous because it ensures reliable sealing of the interior from the outside, while simultaneously allowing for easy temperature measurement. In particular, this also allows for the deformability mentioned below. The partition wall can, for example, have a thickness of at least 0.5 mm or at least 1 mm.

[0022] In particular, it can be provided that the partition has a thermal conductivity of at most 40 W / mK, in particular at 20 °C. This can in particular ensure that heat is not dissipated to surrounding components such as the container wall or the connecting piece. This can enable temperature measurement to be carried out with high accuracy. In particular, it can be provided that the partition is fully or partially elastically deformable. Preferably, the elastic deformability can be limited by the temperature sensor. In particular, this can ensure that the partition rests against the temperature sensor at high pressure, thus ensuring direct contact between the partition and the temperature sensor. This can improve temperature measurement.Elastic deformability is understood in particular to mean that the partition wall deforms when the pressure in the interior increases and returns to its initial state when the pressure drops again accordingly.

[0023] The technology disclosed here further relates to a pressure vessel system comprising a plurality of pressure vessels, at least one of which is configured as described herein. In particular, several or all pressure vessels of the pressure vessel system can be configured as described herein. With regard to the pressure vessel, all embodiments and variants described herein can be used.

[0024] In particular, the pressure vessel system can be designed as a flat storage device. This makes it possible, in particular, to achieve a pressure vessel system with a low height compared to one-plane expansion. This allows the pressure vessel system to fit, for example, into the underfloor space of a motor vehicle. In particular, a pressure vessel as described herein can also contain multiple temperature sensors. These can each be designed with the same features as described herein.

[0025] The pressure vessel system disclosed here, or a corresponding pressure vessel, can be used in particular for a motor vehicle (e.g., passenger cars, motorcycles, commercial vehicles). The pressure vessel system serves to store fuel that is gaseous under ambient conditions. The pressure vessel system can be used, for example, in a motor vehicle powered by compressed (also called compressed natural gas or CNG) or liquefied (also called liquid natural gas or LNG) natural gas or hydrogen. The pressure vessel system is fluidly connected to at least one energy converter configured to convert the chemical energy of the fuel into other forms of energy.

[0026] The pressure vessel can be designed, for example, as a composite overwrapped pressure vessel. The pressure vessel can be, for example, a cryogenic pressure vessel or a high-pressure gas vessel.

[0027] High-pressure gas cylinders are designed to permanently store fuel at ambient temperatures at a nominal working pressure (also called NWP) of at least 350 bar (= overpressure compared to atmospheric pressure) or at least 700 bar. A cryogenic pressure cylinder is suitable for storing fuel at the aforementioned operating pressures even at temperatures that are significantly (e.g., more than 50 K or more than 100 K) below the operating temperature of the vehicle.

[0028] The pressure vessel system can, in particular, be a component of a pressure vessel assembly (also called a "container assembly"). This pressure vessel assembly can comprise the pressure vessels as well as support, fastening, and / or protective elements permanently connected to the pressure vessels (e.g., protective shields, shielding, barrier layers, covers, coatings, wrappings, etc.). The support, fastening, and / or protective elements can, for example, be dismantled only temporarily and preferably only by qualified personnel and / or not non-destructively. Such a pressure vessel assembly is particularly suitable for shallow installation spaces, in particular in the underfloor area beneath the vehicle interior. The pressure vessel assembly can preferably be mounted as a whole in the installation space provided in the motor vehicle. For this purpose, the pressure vessel assembly can have common body connection points by means of which the system as a whole can be secured in the motor vehicle.Preferably, the pressure vessel assembly or the pressure vessel system comprises more than three or more than five or more than seven or more than ten pressure vessels.

[0029] The end piece already described herein can in particular be designed as an on-tank valve (OTV). This typically includes a combination of an electromagnetically operated valve, a manually operated valve, and a thermal pressure relief device. The electromagnetically operated valve and the manually operated valve can in particular be connected in series, one of which can represent a tank shut-off valve. Furthermore, an on-tank valve can typically also have a bleed port or a bleed valve. A bleed port is typically a connection through which gas can be vented from a pressure vessel even if the valves fail. A bleed valve is typically a valve with such functionality. The on-tank valve is typically the valve unit mounted directly at one end of the pressure vessel and directly fluidically connected to the interior of the pressure vessel.

[0030] In other words, it is particularly desirable, especially in the development of flat storage tanks, to be able to replace a temperature sensor without having to remove the tank from the vehicle. With existing designs, replacing the temperature sensor requires a certain amount of effort, because in addition to the line, the entire contents of the flat storage tank are typically emptied beforehand, flushed after the sensor replacement, and then tested for leaks. This requires a corresponding gas consumption.

[0031] Therefore, the aforementioned partition, for example in the form of a metal sleeve, can preferably be arranged between the temperature sensor and the interior. This prevents fluid communication between the flat storage tank contents and the ambient air when the temperature sensor is removed. The temperature sensor can be screwed in, for example. Alternatively, it could be plugged in. This allows, for example, a better adjustment of the rotational position of the electrical connector. Plugging in is possible, for example, because the temperature sensor no longer serves as a seal against the operating pressures of a pressure vessel.

[0032] In addition, this allows for a reduction in the thread length in the sensor. Furthermore, the length of the pressure sensor and / or the partition wall can be further reduced because a seal is no longer required. The tip of the sensor typically provides contact and the best possible contact with the metal sleeve or partition wall.

[0033] A metal sleeve, particularly a thin-walled metal sleeve, or more generally a partition, serves the specific purpose of elastically deforming it under pressure in the pressure vessel, causing it to bend toward the tip of the temperature sensor. This eliminates the need for end-to-end contact between the tip and sleeve, allowing for temperature sensor length tolerance compensation. Furthermore, the thin-walled metal sleeve typically results in very low heat conduction toward the connector or vessel wall. This prevents the temperature measurement from being distorted. For designs that require removal of the partition to replace the temperature sensor, this still offers the advantage of saving gas for purging.

[0034] The metal sleeve can also be designed as a separate component. It is typically thin-walled. This can, for example, reduce the number of variants of the end piece or pressure vessel. In other words, the temperature sensor can be screwed into any pressure vessel of the pressure vessel system or the flat storage tank. Instead of using a thread on the temperature sensor, a plug-in connection is also possible. It is also possible to manufacture the metal sleeve or the partition wall from a particularly poorly conductive material.

[0035] According to a simple implementation, a temperature sensor replacement procedure requires disassembling the temperature sensor to be replaced and installing a new one. According to an alternative prior art implementation, the temperature sensor replacement procedure requires the following steps:

[0036] Control the valve to open, for example via a special process in the control unit,

[0037] Empty the flat accumulator to, for example, 50 bar (there are typically no restrictions on withdrawal rates up to 50 bar), close the valve, for example, via a special process in the control unit, empty the withdrawal line to, for example, 20 bar (a pressure difference between the tank and the withdrawal line of a few bar is normally set during regular shutdown. This is particularly useful for leak diagnosis during vehicle operation. If the pressure difference is not present when the vehicle is started, a leaky valve can be detected).

[0038] Dismantling the temperature sensor to be replaced and installing the new temperature sensor.

[0039] Preferably, a temperature sensor in a pressure vessel system is located near the first pressure vessel in the direction of flow during refueling. This allows for advantageous monitoring of the temperature during a refueling process.

[0040] The technology disclosed here will now be explained using the figures. They show:

[0041] Fig. 1 : a pressure vessel according to the prior art,

[0042] Fig. 2: a pressure vessel according to a first embodiment, Fig. 3: a pressure vessel according to a second embodiment, Fig. 4: a pressure vessel according to a third embodiment, and Fig. 5: a pressure vessel according to a fourth embodiment.

[0043] Fig. 1 shows a purely schematic representation of a pressure vessel 10 according to the prior art. The pressure vessel 10 is shown only partially and in cross-section. This also corresponds to the views in the following figures.

[0044] The pressure vessel 10 has a vessel wall 20. This encloses an interior space 25 in which gaseous fuel can be stored. The interior space 25 is largely delimited on the inside by a liner 22, wherein the liner 22 represents a permeation barrier against the escape of gaseous fuel from the interior space 25 and lies directly against the vessel wall 20 or the end piece described below. This can increase the tightness. Depending on the design of the vessel wall 20, for example depending on the material, such a liner 22 can also be omitted. The vessel wall 20 has an opening 27 which is closed by an end piece 30. In particular, such an end piece 30 is inserted into such an opening 27, connected to the liner 22 and stabilized, for example, by wrapping the assembly with carbon fiber reinforced plastic or another material.It is typically made of a different material than the container wall 20. However, in alternative designs, the end piece 30 may be omitted.

[0045] A temperature sensor 40 is arranged in the end piece 30. The temperature sensor 40 is provided with an external thread 42, by means of which it is screwed into the end piece 30. The temperature sensor 40 protrudes into the interior 25, as shown, and measures the temperature of the gaseous fuel stored in the interior 25. In the embodiment shown, it is typically necessary to seal the temperature sensor 40 from the end piece 30. A seal 50 is used for this purpose. If the temperature sensor 40 is replaced, this can be done by unscrewing it, but typically requires that the interior 25 is first emptied and then refilled.

[0046] Fig. 2 shows a pressure vessel 10 according to a first embodiment of the technology disclosed here. In contrast to the embodiment of Fig. 1, a partition 60 is provided which partially delimits the interior 25. Thus, it is not only the vessel wall 20 and the end piece 30 that delimit the interior 25, but also the partition 60. The partition 60 is formed integrally with the end piece 30, for example by a welded connection. The temperature sensor 40 is also fastened in the end piece 30, but is located on a side of the partition 60 opposite the interior 25. This ensures that the temperature sensor 40 does not come into contact with gaseous fuel stored in the interior 25. Rather, the temperature sensor 40 is arranged outside the volume in which the gaseous fuel is stored and can thus be easily replaced. In addition, the temperature sensor 40 shown in Fig.1 mentioned seal can be omitted, since the partition wall 60 ensures tightness.

[0047] Fig. 3 shows a pressure vessel 10 according to a second exemplary embodiment. In contrast to Fig. 2, the temperature sensor 40 is shortened, as is the partition wall 60. For example, the partition wall 60 can be provided to protrude only approximately 10 cm into the interior space 25 compared to the end piece 30. This allows the internal volume available for storing gaseous fuel to be increased.

[0048] Fig. 4 shows a pressure vessel 10 according to a third exemplary embodiment. In contrast to the embodiment in Fig. 3, the area around the temperature sensor 40 is narrowed in that the partition wall 60 lies closer to the temperature sensor 40. This applies both axially in a direction to the right and radially. In particular, this leads to a high internal pressure, which is reached at typical operating pressures in the pressure vessel 10, causing the partition wall 60 to deform elastically and thus lie directly against the temperature sensor 40. This results in particularly good temperature measurement, since the temperature sensor 40 is directly contacted by the partition wall 60, which in turn is in direct contact with the gaseous fuel whose temperature is to be measured. The functionality of easy replacement is thus retained. Fig. 5 shows a pressure vessel 10 according to a fourth exemplary embodiment.In contrast to the previous exemplary embodiments, a temperature sensor module 70 is provided, which has an external thread 72 and is thus screwed into the end piece 30. To seal the temperature sensor module 70 against the end piece 30, a seal 50 is provided, similar to the embodiment in Fig. 1. The temperature sensor 40 is a component of the temperature sensor module 70. The partition wall 60 is also a component of the temperature sensor module 70. The temperature sensor 40 is detachably fastened in the temperature sensor module 70, for example by being screwed in or by means of a positive connection (not shown). In this case, too, the partition wall 60 shields the temperature sensor 40 from the interior space 25. This also achieves the advantage of separating the temperature sensor 40 from the stored gaseous fuel.In the event that replacement is necessary, a high operating pressure in the interior 25 cannot typically be maintained because, at typical operating pressures, the partition wall 60 presses against the temperature sensor 40 and prevents removal. However, lowering the internal pressure in the interior 25 is sufficient, whereby the stored gaseous fuel can in principle remain in the interior 25. In designs known from the prior art, in which the temperature sensor closes an opening and the tightness of this opening is no longer ensured when the temperature sensor is removed, it was typically necessary to purge the interior with nitrogen to prevent the formation of an ignitable mixture when replacing the temperature sensor.

[0049] For the sake of readability, the term "at least one" has been partially omitted. If a feature of the technology disclosed here is described in the singular or indefinitely (e.g., the pressure vessel, the end piece, etc.), the plural form is also intended to be disclosed (e.g., the at least one pressure vessel, the at least one end piece, etc.).

[0050] The foregoing description of the present invention is for illustrative purposes only and not for the purpose of limiting the invention. Various changes and modifications are possible within the scope of the invention and its equivalents.

[0051] List of reference symbols

[0052] 10 pressure vessels

[0053] 20 Container wall

[0054] 22 liners

[0055] 25 Interior

[0056] 27 Opening

[0057] 30 final piece

[0058] 40 Temperature sensor

[0059] 42 external thread

[0060] 50 Seal

[0061] 60 partition wall

[0062] 70 Temperature sensor module

[0063] 72 external threads

Claims

Claims 1 . Pressure vessel (10) for storing gaseous fuel, comprising - a container wall (20) forming an interior space (25) for receiving the gaseous fuel, - a temperature sensor (40), and - a partition wall (60) which partially delimits the interior space (25) towards the outside, wherein the temperature sensor (40) is detachably fastened to the container wall (20), wherein the partition wall (60) separates the temperature sensor (40) from the Interior space (25), and wherein the temperature sensor (40) is detachably attached independently of the partition wall (60).

2. Pressure vessel (10) according to claim 1, wherein the vessel wall (20) has an opening (27), and wherein the pressure vessel (10) has a closure piece (30) which closes the opening (27).

3. Pressure vessel (10) according to claim 2, wherein the partition wall (60) is attached directly to the end piece (30).

4. Pressure vessel (10) according to claim 2 or 3, wherein the partition wall (60) is attached to the end piece (30) in such a way that it cannot be removed without destruction.

5. Pressure vessel (10) according to one of claims 2 to 4, wherein the temperature sensor (40) is releasably attached to the end piece (30).

6. Pressure vessel (10) according to one of claims 2 or 5, wherein the pressure vessel (10) has a temperature sensor module (70), wherein the temperature sensor module (70) has the temperature sensor (40) and the partition wall (60) and is releasably fastened in the end piece (30).

7. Pressure vessel (10) according to claim 1, wherein the partition wall (60) is attached directly to the vessel wall (20).

8. Pressure vessel (10) according to one of claims 1 or 7, wherein the partition wall (60) is attached to the vessel wall (20) in such a way that it cannot be removed without destruction.

9. Pressure vessel (10) according to one of claims 1, 7 or 8, wherein the temperature sensor (40) is releasably attached directly to the vessel wall (20).

10. Pressure vessel (10) according to claim 6, wherein the temperature sensor (40) is releasably attached to the temperature sensor module (70).

11. Pressure vessel (10) according to one of the preceding claims, wherein the partition wall (60) extends into the interior (25) by a maximum of 10 cm starting from an immediately adjacent section of the pressure vessel (10).

12. Pressure vessel (10) according to one of the preceding claims, wherein the partition wall (60) has a thickness of at most 2 mm.

13. Pressure vessel (10) according to one of the preceding claims, wherein the partition wall (60) has a thermal conductivity of at most 40 W / mK at 20 °C.

14. Pressure vessel (10) according to one of the preceding claims, wherein the partition wall (60) is wholly or partially elastically deformable and the elastic deformability is limited by the temperature sensor (40).

15. Pressure vessel system comprising a plurality of pressure vessels (10), at least one of which is designed according to one of the preceding claims.

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