Pressure vessel and motor vehicle

Abstract

According to the present application, the technology disclosed herein relates to a pressure vessel, preferably a cryogenic pressure vessel, having an inner vessel 100, an outer vessel 200 and an at least partially evacuated space V. The technology disclosed herein also relates to a motor vehicle having such a pressure vessel.

Description

[0001] This application is a divisional application of the application patent application with the international application number PCT / EP2020 / 075829, the national application number 202080065747.9, the filing date 16.09.2020, and the name "Pressure vessel and motor vehicle". BACKGROUND

[0002] The document DE102015204623A1 discloses a cryogenic pressure vessel with a low temperature for the installation of an internal container with a suspension, wherein fiber-reinforced tubes arranged in each other form a heat dissipation distance between the internal container and the outer container. This design requires a comparatively large installation space. From the document EP2217845B1 a cryogenic pressure vessel with a heat exchanger for heating fuel is known. The disadvantage of this technology is that the pressure vessel is relatively heavy, large, complex and expensive, especially due to the heat exchanger and the like, and that heat can only be introduced if fuel is extracted. From the document DE102015213563A1 a barrier layer is known to prevent components escaping from a plastic material layer from entering the vacuum. It is necessary to make the barrier layer design more robust. It is known to equip a pressure vessel with a mechanical overpressure safety valve which is triggered in the event of an excess pressure. SUMMARY

[0003] A preferred task of the technology disclosed here is to reduce or eliminate at least one of the disadvantages of previously known solutions or to propose an alternative solution. In particular, a preferred task of the technology disclosed here is to improve a cryogenic pressure vessel, in particular in terms of cost, installation space requirement, weight, robustness and / or operating characteristics. Other preferred objects can result from the advantages of the technology disclosed here.

[0004] The technology disclosed here relates to a pressure vessel for a motor vehicle, for example a passenger car, a motorcycle, a commercial vehicle. The pressure vessel is used to store a fuel which is gaseous at ambient conditions. The pressure vessel can be used, for example, in a motor vehicle operated with compressed (compressed natural gas) or liquefied (LNG) natural gas or hydrogen. Such a pressure vessel usually supplies an energy converter, for example a fuel cell system, an internal combustion engine, with fuel. The pressure vessel can be part of an anode subsystem of a fuel cell system. The anode subsystem comprises all fuel-guiding components of the fuel cell system.

[0005] A cryogenic pressure vessel can store fuel in a liquid or in a supercritical condensed state. A supercritical condensed state is a thermodynamic state of a substance having a higher temperature and pressure than the critical point. The critical point represents a thermodynamic state at which the densities of gas and liquid of a substance coincide, i.e. the substance exists in a single phase. In a p-T diagram, the end of the vapor pressure curve is marked by the triple point, while the critical point represents the other end. For hydrogen, the critical point is 33.18 K and 13.0 bar. Cryogenic pressure vessels are particularly suitable for storing fuel at temperatures significantly below the operating temperature of a motor vehicle, meaning the temperature range of the vehicle environment in which the vehicle shall be operated, for example at least 50 Kelvin, preferably at least 100 Kelvin or at least 150 Kelvin below the working temperature of a motor vehicle, typically about -40°C to about +85°C. For example, the fuel can be hydrogen, which is stored in the cryogenic pressure vessel at temperatures of about 34 K to 360 K.

[0006] The inner vessel of the pressure vessel, in particular of the cryogenic pressure vessel, can be designed for a nominal operating pressure (also referred to as nominal working pressure or NWP) of about 350 baru (= overpressure compared to atmospheric pressure) or more, preferably of about 500 baru or more, more preferably of about 700 baru or more. The fuel is stored in the inner vessel. The outer vessel at least partially surrounds the inner vessel and outwardly encloses the pressure vessel. Preferably, the cryogenic pressure vessel comprises an at least partially evacuated space having an absolute pressure of 10 -9 mbar to 10 - 1 mbar, more preferably of 10 -7 mbar to 10 -3 mbar and particularly preferably of about 10 -5 mbar. The at least partially evacuated space is arranged at least locally between the inner vessel and the outer vessel. Storing at a temperature (just) above the critical point has the advantage that the storage medium exists in a single phase. For example, there is no interface between the liquid and the gaseous state.

[0007] The inner vessel can comprise an inner liner. The inner liner forms a hollow body in which the fuel is stored. For example, the inner liner can be made of aluminum or steel or an alloy thereof. The inner vessel can comprise at least one fiber-reinforced layer. The fiber-reinforced layer can preferably at least partially completely surround the inner liner. The fiber-reinforced layer is also often referred to as a laminate or a jacket or a reinforcement layer. Fiber-reinforced plastics, such as carbon fiber-reinforced plastics and / or glass fiber-reinforced plastics, are often used as fiber-reinforced layers. The fiber-reinforced layer suitably comprises reinforcing fibers embedded in a plastic matrix. The fiber-reinforced layer usually comprises continuous fibers, which are introduced into the fiber-reinforced layer, preferably by winding and / or weaving.

[0008] According to the technology disclosed herein, the pressure vessel can be provided with a connection end section which is connected with the inner liner and / or the fiber reinforcement layer. Such a connection end section is also referred to as a boss. Preferably, the connection end section is made of a metallic material. The connection end section is particularly preferably connected with the inner liner in a material-locking manner, for example by means of at least one weld seam. In one embodiment, the inner liner and the connector end section are made of the same material. Particularly preferably, the connection end section is arranged parallel to the longitudinal axis of the pressure vessel and particularly preferably coaxially to the longitudinal axis of the pressure vessel. The connection end section regularly projects into the inner volume of the inner vessel. The connection end section is preferably configured in the shape of a pot, wherein a peripheral wall and an end wall which project into the inner vessel form the pot shape. In the installed position, the end side of the connection end section which is inside is arranged set back inwardly with respect to the end of the inner vessel in the direction of the longitudinal axis of the pressure vessel.

[0009] The inner vessel can be mechanically coupled to the outer vessel by means of at least one connection element. The inner vessel is preferably coupled to the outer vessel at both ends by means of a connection element. The connection element is expediently at least partially made of a fiber composite material. Furthermore, the connection element preferably comprises at least one fiber-reinforced tube. The connection element, in particular the fiber-reinforced tube, is expediently configured as a thermal break, so that in the installed state at least 70% or at least 80% or at least 95% or at least 99% of the heat introduced into the connection element on the outer vessel is not transferred to the inner vessel by means of the connection element. The suspension of the tube and the fixation of the tube can be designed in the manner as disclosed in German patent application DE 102015204623 A1. The entire content of German patent application DE 102015204623 A1 is incorporated herein by reference. In one particularly preferred embodiment, the connection element is designed as a connection element which can be inserted into the connection end section. Here, at least one outer peripheral surface of the connection element can preferably rest, for example by means of a slight press fit, on an inner peripheral surface of the connection end section. This design is particularly advantageous, inter alia, in terms of assembly and vacuum tightness. Furthermore, the vacuum space between the inner vessel and the outer vessel can be reduced. In particular, the outer peripheral surface of the connection element and the inner peripheral surface of the connection end section can be configured to be movable relative to one another in the direction of the longitudinal axis of the pressure vessel in order to compensate for length changes. A floating bearing can thus be realized particularly easily by providing possible sliding elements in the intermediate layer.

[0010] Particularly preferably, a fixed bearing is provided at one end at which the filling and extraction line is provided, and a floating bearing is provided at the opposite end.

[0011] In the inner container at least one electric heating element can be provided for heating the fuel. For this purpose any suitable heating element can be used, for example an electric resistance heating element. Such a heater is comparatively simple and inexpensive. The heating element is preferably configured as a heating rod. The heater is expediently designed to generate a temperature of approximately 80°C to 350°C or 100°C to 200°C on its heating surface. In the installed position the heating element can extend parallel to and in particular coaxially to the pressure vessel longitudinal axis of the inner container. The heating element can extend on or substantially on the pressure vessel longitudinal axis of the pressure vessel. The heating element is thus advantageously arranged in the centre of the pressure vessel. The heating element is advantageously configured as a heating rod with a free end. This is particularly advantageous in terms of assembly of the heating element and more uniform heating of the fuel. The heating element can be at least partially surrounded by a metal sleeve. The heating element can in particular be provided at an end of the inner container which is opposite the other end at which the line for filling and / or extraction is provided. This design is advantageous in terms of manufacture. It is also conceivable for the heating element to be provided at the end at which the line for filling and / or extraction is provided. Advantageously, a mixing element can be provided on the heating element here which mixes the fuel which flows in during refuelling. Alternatively or additionally, the refuelling line which projects into the inner volume can be supported on the heating element. The ratio of the heating length of the heating element, i.e. the length of the surface of the heating element which performs the heating, to the total length of the inner container, i.e. the length of the inner container from one end to the other, is preferably between 0.1 and 0.8 or between 0.25 and 0.5, with the heating length being the numerator and the total length of the inner container being the denominator. The heating element can project into the inner volume from the inside and the recessed or indented end side of the connecting end section. The heating element can have a metal sleeve which surrounds the heating element and screens or surrounds the fuel in a fuel-tight manner. The metal sleeve can be connected to the connecting end section in a fuel-tight manner, in particular by a material-locked connection, preferably by at least one weld.

[0012] The end side is spaced apart from the fiber-reinforced layer which at least partially surrounds the inner liner, so that the heat generated by the heating element cannot heat the fiber-reinforced layer to a temperature which is higher than the limit temperature. The limit temperature can be determined in a test, for example, or can be determined taking into account possible technical specifications, such as standards, for example. The limit temperature can be in the range of approximately 50°C to 150°C, or approximately 70°C to 120°C, or approximately 80°C to 90°C, for example. The connecting end section of the pot shape thus serves as a heat dissipation distance, in order to thereby introduce as little heat as possible into the fiber-reinforced layer by thermal conduction, so that the fiber-reinforced layer does not suffer thermal damage. The heating element can thus advantageously be operated at a higher temperature, so that the required heat exchange surface - and thus also the heating element itself - can be designed to be smaller. The electrical lines of the heating element are particularly preferably guided within the connecting element.

[0013] The fiber-reinforced layer and / or the inner liner can be configured or jointly configured as a plastics material layer. It can occur relatively frequently, especially during the manufacture of the fiber-reinforced layer, for example by winding and / or braiding, that gas inclusions cannot be completely removed. These gas inclusions can penetrate into the evacuated space. According to the technology disclosed here, the barrier layer can substantially gas-tightly separate the plastics material layer from the evacuated space. The barrier layer serves to reduce and preferably prevent the penetration of gas outgassing products into the evacuated space, which have penetrated into the plastics. The barrier layer can be provided, for example, to hinder the three sub-steps of absorption, diffusion and desorption which determine the penetration, in particular to hinder diffusion. To this end, the barrier layer can provide as small a free volume as possible, i.e. only a small free space between the molecular chains, for example in the case of polymers.

[0014] Substantially gas-tight means that no account is taken of a negligible amount of gas which has no noticeable effect on the vacuum quality, for example a very small amount of gas which has diffused through the barrier layer. The term "substantially gas-tight" always includes the term "gas-tight". Suitably, the barrier layer encloses at least 70% or at least 90% or at least 99% of the inner volume. Advantageously, the barrier layer itself constitutes the boundary or outermost layer of the inner container from the evacuated space. The barrier layer itself is suitably made of a material which does not outgas, so that a deterioration of the insulation due to outgassing of the barrier layer can be avoided. The barrier layer can be configured as a metal layer, in particular composed of aluminum, steel and / or copper and alloys thereof. The barrier layer can alternatively be made of a fuel barrier plastic, for example of ethylene vinyl alcohol copolymer (EVOH). In general, a high filler content or a high crystallinity in thermoplastics and, in the case of elastomers and thermosets, a high crosslinking degree inhibit diffusion. The barrier layer preferably has a layer thickness of about 0.1 mm to 5 mm or about 0.25 mm to about 2 mm or about 0.5 mm to about 1 mm. The barrier layer is particularly preferably configured as a body (also referred to as a hard containment structure or encapsulation structure) i) within which the layer of plastic material and the inner volume of the inner container are arranged, and ii) which is substantially gas-tight with respect to the evacuated space which abuts on the outer side of the body. A surface coating can advantageously form the barrier layer. However, a gap can also be formed at least locally between the barrier layer and the layer of plastic material. For example, such a gap can be dimensioned such that different thermal expansions in the radial direction of the different material layers, for example the inner liner, the fiber reinforcement layer and / or the barrier layer, can be compensated. Furthermore, outgassed gases can accumulate in the space formed by the gap together with the layer of plastic material and the barrier layer. The space formed by the gap together with the layer of plastic material and the barrier layer is preferably configured such that outgassed gases cannot reach the evacuated space.

[0015] In the technology disclosed here, the gas inclusions present in the layer of plastic material do not have a negative effect on the long-term insulation properties of the pressure vessel. At the same time, a relatively large amount of fuel can be stored in the inner container due to the relatively high internal container pressure associated with a low temperature.

[0016] The barrier can comprise a length compensation device which is arranged to substantially airtightly compensate for length changes of the inner container, in particular by reversible elastic deformation. The length compensation device can comprise at least one bellows element. A bellows is an element which can be folded like an accordion. By elastic deformation of the usually zigzag arranged elements, a large elastic deformation can be achieved with a small installation space. The length compensation device is preferably arranged directly adjacent to (and particularly preferably at) an end of the inner container which is configured as a floating support. The fixed support is particularly preferably provided at an end of the inner container at which the filling and withdrawal line leads out of the inner container and at the opposite end the floating support is configured. The barrier can comprise an annular plate which extends radially outwards (i.e. perpendicular to the longitudinal axis of the pressure vessel) from the connecting end section. The length compensation device can be fixed on the outer edge of the annular plate. Usually, the annular plate comprises a through-hole in the centre, in which the connecting end section is arranged. The annular plate can have a connecting flange at the through-hole. Likewise, the annular plate can be made in one piece with the connecting element. The maximum outer diameter of the barrier can be greater than the maximum outer diameter of the annular plate. The annular plate and / or the length compensation device can be arranged recessed or indented in the axial direction of the inner container relative to the outer boundary of the connecting end section. In other words, the plate and / or the length compensation device is preferably neither radially nor axially protruding. Rather, the length compensation device is arranged in the usually unused annular area of the polar cover. The barrier, in particular the length compensation device and / or the annular plate, can be made of a metallic material, preferably of aluminium, steel and / or copper and alloys thereof. Suitably, at least some and preferably all of the elements of the barrier are connected to one another in a material-locked manner, in particular by a weld seam. A substantially airtight barrier which completely surrounds the inner container can thus be easily and reliably constructed. The barrier is particularly preferably connected to one or both connecting end sections of the inner container in a material-locked and substantially airtight manner. Instead of or in addition to the material-locked attachment of the annular plate to the connecting element, a force-locked connection (e.g. a press fit by shrinkage) or a form-locked connection can also be achieved. This gap can form a substantially airtight space between the layer of plastic material and the barrier. The pressure vessel is suitably configured such that the gas composition in the substantially airtight space can be evaluated from the outside. For this purpose, a sensor can be installed in the space. The substantially airtight space is particularly preferably provided with at least one inspection connection which leads out of the outer container. Thus, the outgassing gas can be easily checked. Alternatively or additionally, the substantially airtight space can be at least to some extent evacuated via the inspection connection. The inspection connection then serves as an evacuation connection. At least one radiation insulator can be provided outside the barrier.

[0017] The technology disclosed herein includes, inter alia, a pressure vessel for storing fuel in a motor vehicle, the pressure vessel having a pressure relief device for pressure relief of the pressure vessel, the pressure relief device having at least one pressure relief mechanism which is thermally activatable; and the pressure relief mechanism is directly fluidically connected with the inner volume of the pressure vessel via a pressure relief line. The pressure vessel can be a high-pressure gas vessel or a cryogenic pressure vessel, in particular as disclosed herein. In the present context, the term "directly fluidically connected" means that no shut-off element (e.g. a valve) which can interrupt the flow path is arranged between the inner volume of the pressure vessel and the pressure relief line. At the same time, no shut-off element is suitably arranged between the inner volume of the pressure vessel and the thermally activatable pressure relief mechanism disclosed herein and / or the overpressure relief valve disclosed herein. A possibly non-functional shut-off valve can thus not prevent the pressure relief. The pressure in the pressure relief line deviates from the pressure in the inner volume of the pressure vessel by less than 10% or less than 5% at all times during the prescribed storage and withdrawal of fuel. Larger pressure differences can occur during the pressure relief. The pressure relief is a process of reducing the pressure in the pressure vessel. In particular, the triggering event is not the prescribed withdrawal for the supply of an energy converter, but rather a failure situation. The pressure relief is usually initiated with the opening of at least part of the valve and / or burst element which is directly fluidically connected with the pressure vessel. If a disturbance situation occurs due to a functional failure of another component and / or due to an external thermal action and / or mechanical action (e.g. an accident, a local fire, etc.), the pressure relief device is arranged to reduce the pressure in the pressure vessel. The pressure relief device can be suitably arranged to achieve a fuel withdrawal mass flow for the pressure relief of the pressure vessel which is greater than the maximum fuel withdrawal mass flow achieved via the withdrawal path to at least one energy converter (usually via at least one tank shut-off valve) (e.g. at least 2 times, 5 times, 10 times, 100 times or more). The entire pressure relief device is usually not used for filling the pressure vessel system and / or for withdrawing fuel to provide energy in the motor vehicle in the event of a disturbance situation during operation. At least part of the flow path parallel to the anode subsystem can be suitably used for the pressure relief. Usually, the pressure vessel internal pressure is reduced to atmospheric pressure due to the pressure relief.

[0018] The technology disclosed herein can include at least one thermally activatable pressure relief mechanism, also referred to as thermal pressure relief mechanism (= TPRD) or thermal fuse mechanism. It is usually arranged adjacent to the pressure vessel. In the event of a thermal action (e.g. due to a fire), the fuel stored in the pressure vessel is discharged via the TPRD to the environment. The pressure relief mechanism discharges the fuel as soon as the triggering temperature (e.g. 110°C) of the TPRD (= thermally activated) is exceeded. Suitably, the TPRD comprises a meltable panel or a glass ampoule. The TPRD can be fluidically connected with the pressure relief line. The pressure relief mechanism can be directly fluidically connected with the inner volume of the pressure vessel via the pressure relief line.

[0019] The pressure vessel can comprise at least one bursting element for pressure relief. The pressure relief mechanism and the bursting element are advantageously in direct fluid connection with the inner volume of the pressure vessel, for example in such a way that the pressure relief mechanism and the bursting element are directly connected to or integrated into the pressure relief line. The bursting element is preferably configured as a burst disc. Generally, the bursting element is relatively inexpensive, takes up little space and is very reliable. In particular, the bursting element can be triggered when the pressure rises to a burst pressure of the bursting element, which is higher than the maximum operating pressure of the pressure vessel and preferably also higher than the trigger pressure of the overpressure safety valve disclosed here. Advantageously, a large mass flow can escape very quickly through the bursting element. The bursting element can be an element that is triggered irreversibly. The bursting element can be arranged outside the outer container. In particular, therefore, no bursting element is involved which ensures the safety of the outer container. To this end, a further bursting element can be provided in the wall of the outer container, which is in fluid connection with the space being evacuated. The bursting element for pressure relief is generally more suitable than the second safety valve. The bursting element also advantageously reduces the number of pressure lines that would otherwise be necessary for the second safety valve. Furthermore, in order to discharge the fuel in the direction of the vehicle floor during pressure relief, a further flow path must be led out of the outer container. However, due to the further flow path, the heat input into the inner container is increased. Overall, this results in a relatively inexpensive, fail-safe and space-optimized pressure relief.

[0020] The system disclosed here comprises at least one overpressure relief valve for discharging fuel. The heat-activatable pressure relief mechanism and the overpressure relief valve are advantageously in direct fluid connection with the inner volume of the pressure vessel, for example in such a way that the heat-activatable pressure relief mechanism and the overpressure relief valve are directly connected to or integrated into a common pressure relief line. The overpressure relief valve can be a device that can be opened and closed again by the pressure in the pressure vessel. In particular, the overpressure relief valve allows the fuel to escape gradually or explosively into the environment or into a collection device outside the vehicle. Such a collection device can be used, for example, in the case of maintenance. Preferably, the overpressure relief valve opens as soon as the pressure in the pressure vessel system has reached or shortly before the pressure in the pressure vessel system reaches the maximum operating pressure of the pressure vessel. The trigger pressure of the overpressure relief valve is preferably lower than the trigger pressure of the overpressure safety valve disclosed here and / or lower than the trigger pressure of the bursting element disclosed here.

[0021] At least one fuel converter is arranged downstream of the overpressure relief valve. The fuel converter can be, for example, a catalytic converter. In particular, the fuel converter can be arranged to catalytically convert fuel, for example hydrogen, escaping through the overpressure relief valve or from other regions of the anode sub-system, using oxygen from the ambient air (in the case of hydrogen, the reaction product is water). The fuel converter and the overpressure relief valve are also referred to as a blow-out management system or an evaporation management system. The fuel converter and the overpressure relief valve are arranged to synthetically convert the fuel to compensate for the internal pressure rising due to the heat input into the inner container (during longer periods of inactivity of the motor vehicle).

[0022] The technology disclosed here also relates to an extraction path to the energy converter, in which at least one further overpressure valve is arranged, and which is in fluid connection with the fuel converter, such that fuel escaping from the extraction path through the further overpressure valve is catalytically converted in the fuel converter. Furthermore, a pressure reducer can be arranged in the extraction path, which reduces the pressure in the extraction path from a first pressure level upstream of the pressure reducer to a second pressure level downstream of the pressure reducer. The further overpressure valve can be arranged downstream of the pressure reducer. Fuel escaping from the medium-pressure region can thus be converted in the fuel converter and does not enter the environment unburned. A throttling element can advantageously be arranged upstream of the fuel converter.

[0023] The pressure vessel system disclosed here also comprises at least one overpressure safety valve. If the pressure in the pressure vessel system is at least partially above the triggering pressure of the overpressure safety valve, the overpressure safety valve unloads the pressure vessel system. The overpressure safety valve is preferably a mechanically openable and closable valve. The triggering pressure is greater than the maximum operating pressure, for example by about 10% to about 20%. In particular, the overpressure safety valve is designed such that it triggers before the overpressure can damage components of the pressure vessel system. The overpressure safety valve is also expediently in direct fluid connection with the inner volume of the pressure vessel. The overpressure safety valve is preferably configured to be externally insertable into the outer container and, in the installed position, is in direct fluid connection with the inner volume of the inner container via a pressure line. Such a design enables easier maintenance. The overpressure safety valve can advantageously be arranged spaced apart from the burst element. In particular, the overpressure safety valve can be arranged on a side of the pressure vessel opposite the side on which the burst element is arranged. For example, the burst element can be arranged at a first end of the pressure vessel and the overpressure safety valve can be arranged at a second end of the pressure vessel opposite the first end. Thereby, at least the burst element or the overpressure safety valve can open in different accident scenarios. Thereby, the pressure relief is safer. Furthermore, different structural elements for pressure relief are employed in the case of the overpressure safety valve and the burst element, whereby the probability of a common cause failure can be reduced.

[0024] The pressure relief line can extend over a peripheral region of the pressure vessel, in particular over a peripheral region of an outer vessel of the pressure vessel at low temperature. The pressure relief line can comprise a plurality of line sections. The pressure relief line in the peripheral region is expediently extended parallel to the longitudinal axis of the pressure vessel. The pressure relief line can have a first line end. Furthermore, the pressure relief line can have a second line end, which opens into the tank shut-off valve and / or into the inner volume of the pressure vessel. The first line end can also be referred to as a distal end with respect to the tank shut-off valve. The second line end can also be referred to as a proximal end with respect to the tank shut-off valve. In one design variant, the first line end can be arranged adjacent to a first end of the pressure vessel, in particular at the transition between the peripheral region and the first end. A burst element and / or an overpressure relief valve can be configured at the first line end. If, for example, the burst element and / or the overpressure relief valve are spaced apart from the tank shut-off valve, for example by a minimum distance of 0.5D or 0.8D, where D is the overall length of the inner vessel, the temperature of the cryogenic fuel increases before the fuel hits the burst element and / or the overpressure relief valve. Since the mass flow into the fuel converter through the overpressure relief valve is relatively small, the fuel temperature can increase significantly. As a result, these components do not have to be designed for the lowest storage temperature in the inner volume. As a result, more suitable components can advantageously be used.

[0025] The pressure vessel disclosed herein also comprises a tank shut-off valve. The tank shut-off valve is a valve whose input pressure substantially corresponds to the vessel pressure. The tank shut-off valve is in particular a controllable or adjustable and in particular a normally closed valve, which is in direct fluid connection with the inner volume of the pressure vessel. In Commission Regulation (EU) No. 406 / 2010 of 26 April 2010 implementing Directive 2009 / 79 / EC of the European Parliament and of the Council on the type-approval of hydrogen-powered motor vehicles, such a tank shut-off valve is also referred to as a first valve, for example.

[0026] The technology disclosed herein also relates to a filling system for cryogenic pressure vessels, in particular for the pressure vessels disclosed herein. The filling system generally comprises a cryogenic filling connection which is fluidically connected with a tank shut-off valve which is operated at cryogenic temperatures herein. The fluidic connection between the tank shut-off valve and the cryogenic filling connection can be equipped with a thermal insulation, for example a partially evacuated space and / or an insulation with foam plastic and / or aerogel. The cryogenic filling connection can be couplable with a corresponding coupling piece on the side of the filling station. Additionally, a further filling connection can be provided for thermal filling. Both filling connections are suitably configured such that the cryogenic filling connection can receive cryogenic fuel having a fuel temperature which is at least 150 Kelvin or at least 180 Kelvin lower than the lowest fuel temperature which can be received by the further filling connection. For motor vehicles filled with hydrogen, in connection with the technology disclosed herein, thermal filling is generally understood to be a filling in which the fuel received in the motor vehicle has a temperature in the tank coupling piece of between about -60°C and about +50°C and preferably between about -40°C and about +35°C. Advantageously, one pressure line can be connected to the further filling connection which, in particular upstream of the cryogenically operated tank shut-off valve, opens into the cryogenic line system in which, preferably, a further tank shut-off valve and / or a pressure-limiting valve are provided in the pressure line. By means of the further tank shut-off valve, filling of the pressure vessel can be reliably prohibited. The pressure-limiting valve can be provided to limit the maximum filling pressure, preferably to a pressure below the maximum permissible pressure which can occur during operation of the pressure vessel (generally the maximum operating pressure). In a flow path fluidically parallel to the cryogenic tank shut-off valve, a filling check valve is provided which allows fuel to pass to the pressure vessel and blocks passage in other operating states, for example extraction or storage. A check valve can also be provided on the filling connection which prohibits fuel from flowing back to the filling station or the environment. The filling system described in this paragraph is functionally independent of the other features of the technology disclosed herein and can be used with cryogenic pressure vessels which differ from the pressure vessels disclosed herein.

[0027] The technology disclosed herein also relates to a sensor assembly for cryogenic pressure vessels, in particular as disclosed herein. The sensor assembly comprises i) at least one sensor element arranged to detect a signal indicative of at least one state variable (e.g. temperature and / or pressure) of fuel stored in the inner vessel, ii) a sensor connection arranged on the outer vessel and by which an evaluation unit (e.g. a controller) can be connected to the sensor element, iii) at least one electric line connecting the sensor element with the sensor connection. The sensor connection and / or the sensor element are preferably received within the inner box hanger, in particular within the connection element disclosed herein. This is particularly advantageous in manufacturing. The sensor connection and the sensor element are particularly preferably arranged coaxially to each other. In case of a maintenance service, the sensor element can thus particularly advantageously be maintained through a recess provided in the outer vessel for the sensor element. It is particularly advantageous that the connection element can serve as a guide when replacing the sensor element and also prevents parts from falling into the evacuated space. For this purpose, the sensor connection and / or the sensor element are preferably designed to be replaceable from the outside. The sensor system described in this paragraph is functionally independent of the other features of the technology disclosed herein and can be used with cryogenic pressure vessels different from the pressure vessels disclosed herein.

[0028] The technology disclosed herein also comprises a motor vehicle having at least one pressure vessel disclosed herein. Preferably, the end of the overpressure relief valve downstream can be fluidically connected with a fuel outlet provided on the roof for conducting fuel to the environment.

[0029] In other words, the technology disclosed herein relates to a number of features, which, although functionally independent of one another, achieve a symbiotic effect when interacting. According to the technology disclosed herein, it can be provided that the pressure vessel comprises a pot-shaped boss, which is preferably welded to the inner liner. A fiber-reinforced inner tank suspension can be inserted into the boss, so that the annular space between the inner container and the outer container can be reduced to a minimum dimension. On the fixed support side, the minimum dimension can be defined by the spatial requirement of the lines, in particular the filling and extraction lines. On the floating support side, the minimum dimension can be defined by the length variation of the inner container due to different pressures and / or temperatures. Advantageously, the installation space can be better utilized or more fuel can be stored in the same installation space. Furthermore, a simpler structure with a lighter weight can thus be achieved. Furthermore, the vacuum stability can advantageously be improved with the inner container suspension disclosed herein, since a smaller amount of gas diffuses from the fiber composite tube into the vacuum. The pressure vessel disclosed herein can comprise an electric heater. The electric heater can be built into a metal sleeve. The sleeve can be welded with the boss. The cable for the heater can be guided inside the inner pressure vessel suspension on the floating support side. The length of the sleeve can be kept relatively short, so that no additional support is required for the vibration load of the top. A sufficient heat dissipation distance can be provided between the heater and the fiber-reinforced layer, whereby, for example, a relatively high temperature of, for example, 200°C at the heater is dissipated in order to produce a maximum temperature of, for example, 85°C on the fiber-reinforced layer. The electric heater or the sleeve surrounding the electric heater advantageously has a smaller outer surface than previously known gas-gas heat exchangers. Furthermore, advantageously, the heater can be operated at a higher temperature of, for example, 200°C and thereby compensates for the relatively small surface and introduces sufficient heat into the pressure vessel. The heat flow can be supplied continuously and can be adjusted by changing the temperature of the heater. A switching valve can advantageously be omitted. Furthermore, two lines for guiding hydrogen are less required. With the electric heater, a greater surface temperature can be achieved, so that the required heat flow can be transferred with a smaller surface. The possible water pump of the pressure vessel system can also be designed smaller in size. The solution disclosed herein is therefore generally simpler and lighter than previously known gas-gas heat exchangers. Advantageously, heat can be introduced into the fuel even without extraction of the fuel from the pressure vessel. The heat input from the outer container to the inner container can be reduced, since the heat flow can no longer flow in by means of heat conduction through the three line walls. The pressure build-up time or the loss-free use time can thereby be improved. The technology disclosed herein generally comprises a hard containment. The hard containment comprises a penetration barrier or barrier layer, which is preferably made of metal, in order to shield the fiber-reinforced layer from the inner container. The hard containment is preferably made of steel, in particular stainless steel. The hard containment consists of 6 build-ups, which are welded to one another.The diaphragm bellows are designed to allow length changes of the inner pressure vessel (caused by temperature and / or pressure changes) without gas entering the evacuated space. Thanks to its hard closure, the inner vessel designed in this way comprises a relatively stable vacuum. The hard closure is more robust than previously known solutions, since possible length changes of the inner pressure vessel do not lead to plastic deformations, but only to reversible elastic deformations, in the case of which the tightness of the hard closure is not negatively affected. Furthermore, the hard closure can be easily and reproducibly manufactured by welding.

[0030] The technology disclosed herein can also be described from the following aspects:

[0031] 1. Cryogenic pressure vessel for storing fuel in a motor vehicle, the pressure vessel having an inner vessel 100 and an outer vessel 200, wherein at least locally between the inner vessel 100 and the outer vessel 200 an evacuated space V is arranged;

[0032] wherein the inner vessel 100 has a layer of plastic material 130; wherein at least locally between the layer of plastic material 130 and the evacuated space V a barrier layer 150 is arranged; wherein the barrier layer 150 is configured and arranged such that it at least reduces the transfer of components escaping from the layer of plastic material 130 into the evacuated space V; and wherein at least locally between the barrier layer 150 and the layer of plastic material a gap S is configured.

[0033] 2. Pressure vessel according to aspect 1, wherein the barrier layer 150 comprises length compensation means 152 which are designed to compensate for length changes of the inner vessel 100, in particular by reversible elastic deformations.

[0034] 3. Pressure vessel according to aspect 2, wherein the length compensation means 152 comprise at least one bellows element.

[0035] 4. Pressure vessel according to aspect 2 or 3, wherein the length compensation means 152 are arranged directly adjacent to an end of the inner vessel 100 which is configured as a floating support.

[0036] 5. Pressure vessel according to one of the preceding aspects, wherein the barrier layer 150 is made of a metallic material.

[0037] 6. Pressure vessel according to one of the preceding aspects, wherein the layer of plastic material is a fiber-reinforced layer 120 which surrounds an inner liner 110; and wherein the barrier layer 150 substantially gas-tightly separates the fiber-reinforced layer 120 from the evacuated space V.

[0038] 7. Pressure vessel according to one of the preceding aspects, wherein the inner vessel 100 has a connection end section 140, wherein the inner liner 110 and / or the fiber reinforced layer 120 are connected with the connection end section 140, wherein the connection end section 140 is connected with the barrier layer 150 in a materially bonded and substantially gas-tight manner.

[0039] 8. Pressure vessel according to one of the preceding aspects, wherein the barrier layer 150 comprises an annular plate 154 extending radially outwardly from the connection end section 140.

[0040] 9. Pressure vessel according to one of the preceding aspects, wherein the length compensation device 152 is arranged on an outer edge of the annular plate 154 and the annular plate 154 and / or the length compensation device 152 are arranged axially rearwardly of the outer boundary 146 of the connection end section 140.

[0041] 10. Pressure vessel according to one of the preceding aspects, wherein a substantially gas-tight space GR is configured between the barrier layer 150 and the layer of plastic material; and the pressure vessel is configured such that a gas composition in the substantially gas-tight space GR can be assessed from the outside.

[0042] 11. Pressure vessel according to the preceding aspect, wherein the substantially gas-tight space GR comprises at least one inspection port and the inspection port leads out of the outer vessel 200.

[0043] 12. Pressure vessel according to one of the preceding aspects, wherein at least one radiation insulator is arranged outside the barrier layer 150.

[0044] a) Pressure vessel for storing fuel in a motor vehicle, in particular according to any one of the preceding aspects 1 to 12, having a pressure relief device 170 for pressure relief of the pressure vessel, the pressure relief device 170 having at least one pressure relief mechanism 172, 174 which can be activated thermally; and the pressure relief mechanism 172, 174 is directly fluidically connected with the inner volume I of the pressure vessel via a pressure relief line 171.

[0045] b) Pressure vessel according to aspect a), further comprising at least one burst element 176, wherein the pressure relief mechanism 172, 174 and the burst element 176 are directly fluidically connected with the inner volume I of the pressure vessel.

[0046] c) The pressure vessel according to aspect a or b, further comprising at least one overpressure relief valve 177, wherein downstream of the overpressure relief valve 177 at least one fuel converter 180 is arranged; and the pressure relief mechanism 172, 174 and the overpressure relief valve 177 are in direct fluid connection with the inner volume I of the pressure vessel.

[0047] d) The pressure vessel according to one of the preceding aspects, wherein the pressure relief device 170 comprises an overpressure safety valve 175, wherein the overpressure safety valve 175 is also in direct fluid connection with the inner volume I of the pressure vessel.

[0048] e) The pressure vessel according to aspect d, wherein the overpressure safety valve 175 is arranged spaced apart from the burst element 176.

[0049] f) The pressure vessel according to aspect d or e, wherein the overpressure safety valve 175 is arranged on a side of the pressure vessel opposite to the side on which the burst element 176 is configured.

[0050] g) The pressure vessel according to one of the preceding aspects, wherein the burst element 176 is arranged at a first end portion PI and the overpressure safety valve 175 is arranged at a second end portion P2 opposite to the first end portion PI.

[0051] h) The pressure vessel according to one of the preceding aspects, comprising an inner vessel 100 and an outer vessel 200, wherein between the inner vessel 100 and the outer vessel 200 at least partially a vacuumed space V is arranged, the inner vessel 100 is configured to store the inner volume I of fuel.

[0052] i) The pressure vessel according to one of the preceding aspects, wherein the burst element 176 is arranged outside of the outer vessel 200.

[0053] j) The pressure vessel according to one of the preceding aspects, wherein in a wall of the outer vessel 200 a further burst element 202 is arranged, which is in fluid connection with the vacuumed space V.

[0054] k) The pressure vessel according to one of the preceding aspects, wherein the pressure relief line 171 has a first line end portion 178; and the burst element 176 and / or the overpressure relief valve 177 are configured at the first line end portion 178.

[0055] l) The pressure vessel according to one of the preceding aspects, wherein the pressure relief line 171 extends over a peripheral region of the pressure vessel, preferably of the outer vessel 200.

[0056] m) Pressure vessel according to one of the preceding aspects, wherein the trigger pressure of the overpressure relief valve 177 is lower than the trigger pressure of the overpressure safety valve 175 and / or lower than the trigger pressure of the burst element 176.

[0057] n) Motor vehicle comprising at least one pressure vessel according to one of the preceding aspects.

[0058] o) Motor vehicle according to aspect n, wherein the overpressure safety valve 175 is fluidly connected with a fuel outlet 179 arranged on the roof of the vehicle.

[0059] i) Cryogenic pressure vessel for storing fuel in a motor vehicle, in particular according to one of the aspects 1 to 12 or a to o, having an inner vessel 100 and an outer vessel 200, wherein between the inner vessel 100 and the outer vessel 200 at least a partially evacuated space V is arranged, wherein in the inner vessel 100 at least one electric heating element 130 is arranged for heating the fuel.

[0060] ii) Cryogenic pressure vessel according to aspect i, wherein the heating element 130 extends in the mounted position parallel to the longitudinal axis A-A of the inner vessel 100.

[0061] iii) Cryogenic pressure vessel according to one of the preceding aspects, wherein the inner vessel 100 has a connection end section 140, wherein the inner liner 110 and / or the fiber reinforced layer 120 are connected with the connection end section 140 and the heating element 130 protrudes from an inner end side 142 of the connection end section 140.

[0062] iv) Cryogenic pressure vessel according to aspect iii, wherein the inner end side 142 is spaced apart from the fiber reinforced layer 120 such that the heat generated by the heating element 130 cannot heat the fiber reinforced layer 120 to a temperature above a limit temperature from which a damage of the fiber reinforced layer 120 has a probability to occur.

[0063] v) Cryogenic pressure vessel according to one of the preceding aspects, wherein the heating element 130 is at least partially surrounded by a metal sleeve 135.

[0064] vi) Cryogenic pressure vessel according to aspect v, wherein the metal sleeve 135 is fuel-tight connected with the connection end section 140.

[0065] vii) Cryogenic pressure vessel according to one of the preceding aspects, wherein the heating element 130 is arranged at a first end portion PI of the inner vessel 100, which is opposite to a second end portion P2 at which a line for filling and / or extraction is arranged.

[0066] viii) Cryogenic pressure vessel according to one of the preceding aspects, wherein the inner vessel 100 is mechanically coupled to the outer vessel 200 by at least one connection element 144; and the electrical line 133 of the heating element 130 is guided within the connection element 144.

[0067] ix) Cryogenic pressure vessel according to aspect viii, wherein the connection element 144 is at least partially made of a fiber composite material.

[0068] x) Cryogenic pressure vessel according to one of the preceding aspects, wherein the ratio of the heating length lh of the heating element 130, which extends into the inner vessel 100, to the total length Lioo of the inner vessel 100 is between 0.1 and 0.8 or between 0.25 and 0.5.

[0069] xi) Motor vehicle comprising a cryogenic pressure vessel according to any one of the preceding aspects. BRIEF DESCRIPTION OF DRAWINGS

[0070] The technology herein disclosed will now be explained with the help of the enclosed drawings. In the drawings:

[0071] Figure 1 a schematic cross-sectional view of a pressure vessel herein disclosed is shown;

[0072] Figure 2 a further schematic detailed view of a pressure vessel herein disclosed is shown. DETAILED DESCRIPTION

[0073] Figure 1A view of the pressure vessel system disclosed herein is schematically shown. The pressure vessel comprises an inner vessel 100 surrounded by an outer vessel 200. A vacuumed space V is located between the inner vessel 100 and the outer vessel 200, the inner vessel 100 comprising an inner liner 110 surrounded by a fiber reinforced layer 120. A filling and extraction line 410 is provided here at the second end P2. Likewise, two separate lines for filling and extraction can also be provided. For filling, the pressure vessel here comprises a cryogenic filling connection 432 which is fluidically connected to a tank shut-off valve 420 which here operates at cryogenic temperatures. The fluidic connection between the tank shut-off valve 420 and the cryogenic filling connection 432 is equipped with a thermal insulation 433, for example a partially vacuumed space and / or an insulation with foam plastic and / or aerogel. The cryogenic filling connection 432 can be coupled with a corresponding coupling on the filling station side. In addition, a further filling connection 434 can preferably be provided for hot filling. The two filling connections 432, 434 are suitably configured such that the cryogenic filling connection 432 can receive cryogenic fuel with a fuel temperature which is at least 150 K or at least 180 K lower than the lowest fuel temperature which can be received by the further filling connection 434. A pressure line 435 can advantageously be connected to the further filling connection 434, which pressure line opens into the cryogenic line system in the vacuumed space V, in particular upstream of the cryogenically operating tank shut-off valve 420, wherein a further tank shut-off valve 437 and / or a pressure limiting valve 436 are preferably provided in the pressure line 435. By means of the further tank shut-off valve 437, filling of the pressure vessel can be reliably prohibited. The pressure limiting valve 436 can be set to limit the maximum filling pressure, preferably to the maximum permissible pressure of the pressure vessel which can occur during operation of the pressure vessel (usually the maximum operating pressure). An filling check valve 421 is provided in a flow path which is fluidically parallel to the cryogenic tank shut-off valve 420, which is set to allow fuel to pass to the pressure vessel during filling and to block passage in all other operating states, for example extraction or storage. A check valve 439 is also provided here on the filling connections 432, 434, which prohibits backflow of fuel into the filling station or the environment. The sensor assembly provided at the second end P2 here comprises a sensor element 205 which is set to detect a signal which at least indicates the fuel temperature in the inner volume I. The sensor element 205 is connected to a sensor connection 204 by means of an electrical line 203. Here, the sensor connection 204 is provided on the outer vessel 200 and the sensor element 205 is provided on the inner vessel 100. A controller can be connected or connectable to the sensor element 205 via a suitable element such as an electrical line, a bus system, etc. via the sensor connection 204. The sensor connection 204 and the sensor element 205 are received in a connection element 144.The connecting element 144 at the second end portion P2 is suitably configured as disclosed in connection with the connecting element 144 of the first end portion PI. The sensor joint 204 and the sensor element 205 are coaxially arranged with each other and preferably configured concentrically to the pressure vessel longitudinal axis A-A here. Alternatively or additionally, the sensor element 205, the sensor joint and the electrical line 203 can be arranged (also) at the first end portion PI in the same way.

[0074] The heating element 130 is arranged here at the first end portion PI, which is opposite to the second end portion P2. The heating element 130 is configured here as a heating rod extending concentrically to the pressure vessel longitudinal axis A-A. The heating element 130 is an electrical resistance heater. The heating element 130 comprises a metal sleeve 135, which configures the outer surface of the heating element 130 and thus shields the heating element against the fuel. The heating element 130 is here fuel-tightly welded to the inner end side 142 of the connecting end portion section 140 and extends into the inner volume I of the inner vessel 100. The end side 142 forms together with the peripheral wall 143 the pot-shaped connecting end portion section 140. The connecting end portion section 140, also called boss, comprises a second region, which is here connected to the inner liner 110 (here by at least one weld seam) and which is at least partially surrounded by the fiber-reinforced layer 120. The end side 142 is here spaced apart from the fiber-reinforced layer 120 so far that i) the limit temperature is not reached in the fiber-reinforced layer 120, ii) the annular installation space between the inner vessel and the outer vessel is as small as possible, which is still sufficient to compensate length changes caused by pressure and / or temperature, and the heat dissipation distance in the connecting element 144 is long enough. The connecting element 144 is configured tubular and pushed into the pot-shaped connecting end portion section 140. The connecting element 144 is at least partially composed of a fiber composite material in order to thereby minimize the heat input into the inner vessel and to compensate possible vibrations. The outer surface of the connecting element 144 is here at least partially resting on the inner surface of the peripheral wall 143 (see Figure 2 ) and can be configured as a floating bearing. At least one electrical line 133 can be received inside the connecting element 144. The at least one electrical line supplies the heating element 130 with electrical energy and provides an electrical signal for controlling or regulating the heating element 130. The ratio of the heating length lh of the heating element 130, which extends into the inner vessel 100, to the total length L100 of the inner vessel 100 is between 0.1 and 0.8 or between 0.25 and 0.5.

[0075] The pressure vessel also comprises a pressure relief device 170. The pressure relief device 170 is not used for filling the pressure vessel or for extracting fuel for the energy converter 500. Rather, the pressure relief device 170 is typically used for pressure relief in the event of an interference or a fault or for pressure relief during a long downtime. The filling and extraction line 410 connects the inner volume I of the inner vessel 100 with the line system arranged in the evacuated space V. The filling and extraction line 410 here comprises a T-piece which is in fluid connection with the pressure relief line 171. Likewise, the pressure relief line 171 can open directly into the inner volume I. In the pressure relief line 171, two thermally activatable pressure relief mechanisms (TPRD) 172, 174 are arranged here. For this purpose, the pressure relief line 171 can be formed, for example, from a plurality of line elements between which the thermally activatable pressure relief mechanisms 172, 174 are arranged, respectively. If, for example, a thermal event occurs adjacent to the pressure relief mechanism 174, the pressure relief mechanism 174 opens, for example in such a way that a meltable panel melts or a glass ampoule is broken. The fuel escapes suddenly before the thermal event can cause the inner vessel 100 to burst. This arrangement of TPRDs is particularly space-saving and reliable in operation. It is particularly advantageous if an overpressure relief valve 177 is also configured on the pressure relief line 171 and is in fluid connection with the pressure relief line 171. The overpressure relief valve 177 and / or the thermally activatable pressure relief mechanism 174 and / or the bursting element 176 are preferably configured as close as possible to the first line end 178 or as close as possible to the first end P1. The pressure relief line 171 can thus advantageously be used as a heat exchange line, so that the cryogenic fuel acts on the structural element at a higher temperature than on the other end of the pressure relief line 171 which is directly adjacent to the tank shut-off valve 420. The overpressure relief valve 177 and / or the thermally activatable pressure relief mechanism 174 and / or the bursting element 176 and / or the overpressure safety valve 177 disclosed here are in direct fluid connection with the inner volume I of the pressure vessel here. In other words, no shut-off element, for example a valve, is arranged between the structural element and the inner volume I which can block the flow path for pressure relief.

[0076] A further pressure relief line 171 branches off from the T-piece in the opposite direction, which is in fluid connection with the overpressure safety valve 175. The overpressure safety valve 175 can be arranged such that it is received from the outside into the outer vessel 200. The overpressure safety valve 175 can thus advantageously be replaced without the need for an additional access to the evacuated space V for this purpose.

[0077] An overpressure relief valve 177 is fluidically connected with the fuel converter 180. If the fuel pressure rises above the value of the triggering pressure of the overpressure relief valve 177, fuel can flow from the inner volume I via the pressure relief line 171 and via the overpressure relief valve 177 into the fuel converter 180. The fuel converter 180 is arranged to catalytically convert the fuel. Thereby, no or only a negligible amount of fuel enters the environment. A throttle valve for limiting the relief fuel mass flow can be arranged in the fuel converter 180 or upstream of the fuel converter 180. If fuel cannot be or is not sufficiently discharged via the overpressure relief valve 177 and the fuel converter 180, the pressure in the inner volume continues to rise until the triggering pressure of the overpressure safety valve 175 is reached. The triggering pressure of the overpressure safety valve 175 is thus higher than the triggering pressure of the overpressure relief valve 177. When the overpressure safety valve 175 opens, a mass flow can escape which can be greater than the catalytically convertible mass flow via the fuel converter 180. The fuel can be suitably discharged into the environment or into a fuel suction device by means of suitable fuel discharge means. To this end, for example, a channel can be provided which leads to a roof fin in the roof through which the fuel escapes. If the overpressure safety valve 175 has a functional failure, the pressure in the inner volume I can continue to rise until the triggering pressure of the bursting element 176 is reached, which is higher than the triggering pressure of the overpressure safety valve 175. If the bursting element 176 bursts, a rapid pressure relief also occurs. The overpressure safety valve 175 and the bursting element 176 are constructed differently, so that the probability of both components failing due to the same fault is small. Here, the overpressure safety valve 175 and the bursting element 176 are advantageously constructed at a distance from one another. By constructing the overpressure safety valve 175 at the upper side of the pressure vessel and the bursting element 176 at the lower side of the pressure vessel, the probability that the fuel can still be reliably discharged in the normal position and in the inverted position even in the event of a deformation of the vehicle body increases. For the same reason, the bursting element 176 and the overpressure safety valve 175 are particularly preferably arranged at different ends P1, P2 of the pressure vessel here.

[0078] Furthermore, a tank shut-off valve 420 is directly fluidically connected with the inner volume I of the inner container 100. The tank shut-off valve 420 is only shown schematically. The tank shut-off valve is an electrically operable normally closed valve. The extraction path 411 extends downstream of the tank shut-off valve 420 towards the energy converter 500. In the extraction path a heat exchanger 190 is arranged, which has a coolant inflow path 192 and a coolant outflow path 194. Coolant can be extracted from the coolant circuit of the motor vehicle.

[0079] Figure 2A schematic cross-sectional view of the inner container 100 is shown. The inner container 100 comprises an inner liner 110 surrounded by a fiber reinforced layer 120. At both end portions of the inner liner 100 one connection end section 140, also called boss, is provided, which is here for simplicity identically configured. A barrier layer 150 is provided here spaced apart by a gap S. The barrier layer 150 is here made of a steel alloy. The barrier layer 150 together with the fiber reinforced layer 120 forms a substantially gas-tight space GR. The barrier layer 150 is here configured to completely and substantially gas-tightly surround the main body of the fiber reinforced layer 120 of the inner container 100, so that the vacuum of the vacuumed space V is not reduced in a way that impairs its function. For simplicity, the outer container 200 and other elements of the pressure vessel are omitted.

[0080] Not shown is a possible inspection joint, through which the substantially gas-tight space GR can be externally accessible. If possible gas escapes from the fiber reinforced layer, it cannot escape into the vacuumed space V due to the sealing effect of the barrier layer 150. The gas collects in the substantially gas-tight space GR. In one embodiment, the already escaped gas can be extracted through the inspection joint.

[0081] The gap S can be chosen such that the fiber reinforced layer 120 does not touch the barrier layer 150 even if the inner container 100 is stretched to the maximum in the radial direction. To compensate for the length stretch in the axial direction, the barrier layer 150 comprises here a length compensation device 152. The length compensation device 152 is configured as a bellows or a diaphragm bellows. The length compensation device 152 is substantially gas-tightly fixed with a first end portion PI on an annular plate 154 and substantially gas-tightly fixed with a second end portion P2 on a cover member 157, also called dome member. One or more cover members 157 are in turn substantially gas-tightly connected with a generally cylindrical intermediate member 156. In the present embodiment of the barrier layer 150, the barrier layer comprises one annular plate 154, two cover members 157, one or two intermediate members 156 and one bellows 152. These members are preferably made of a metallic material, here of a steel alloy, and particularly preferably of the same material and so materially lockingly connected with each other that they outwardly enclose the substantially gas-tight space GR. Depending on the manufacturing scheme, fewer or more components or semi-finished products can configure the barrier layer 150. The annular plate 154 is welded to the connection end section 140 at its center. In other words, the plate 154 is a connection between the bellows and the boss. The plate 154 is welded at its radial edges with the bellows. Even if here only one annular plate 154 and one length compensation device 152 are shown, one annular plate 154 and one length compensation device 152 can be provided at each end portion.

[0082] When the inner vessel 100 is stretched in axial direction (here indicated by the arrow), the second end portion P2 moves outwards. This length change is immediately compensated "on site" at the second end portion P2 by the length compensation device 152. The weld seam is shown as a black dot in Figure 2 Depending on the design of the inner vessel 100, less or more weld seams can be provided.

[0083] In the context of the technology disclosed herein, the term "substantially" (e.g. "substantially perpendicular axis") includes the exact property or value (e.g. "perpendicular axis") as well as a tolerable deviation from the property / value which is insignificant for the function of the property / value (e.g. "tolerable deviation from a perpendicular axis").

[0084] The above description of the invention is merely intended for illustrative purposes and is not intended to limit the invention. Various changes and modifications can be made within the scope of the invention without departing from the scope thereof and equivalents thereof. In particular, the features of the invention are not limited to the combination as described above, but can also be combined in other ways.

[0085] i) a tank-shaped connecting element (inner box hanger);

[0086] ii) a heating device;

[0087] iii) a barrier layer;

[0088] iv) a drain valve;

[0089] v) a burst element;

[0090] vi) a filling system; and

[0091] vii) a sensor assembly

[0092] The disclosed features are individually functionally independent on their own and can also be used in other pressure vessels, in particular also in other cryogenic pressure vessels. However, their combination is particularly advantageous.

Claims

1. Pressure vessel for storing fuel in a motor vehicle, the pressure vessel having a pressure relief device (170) for the pressure relief of the pressure vessel, the pressure relief device (170) having at least one pressure relief mechanism (172, 174) which can be activated thermally; and the pressure relief mechanism (172, 174) being directly fluidically connected to the inner volume (I) of the pressure vessel by means of a pressure relief line (171), The pressure vessel further comprises at least one burst element (176), wherein the pressure relief mechanism (172, 174) and the burst element (176) being directly fluidically connected to the inner volume (I) of the pressure vessel, the pressure relief device (170) comprising an overpressure safety valve (175), wherein the overpressure safety valve (175) is also directly fluidically connected to the inner volume (I) of the pressure vessel, the overpressure safety valve (175) being arranged spaced apart from the burst element (176), the overpressure safety valve (175) being arranged on a side of the pressure vessel which is opposite to a side on which the burst element (176) is arranged; and / or the burst element (176) being arranged at a first end portion (PI) and the overpressure safety valve (175) being arranged at a second end portion (P2) which is opposite to the first end portion (PI); and / or the pressure vessel having an inner container (100) and an outer container (200), wherein at least partially between the inner container (100) and the outer container (200) a vacuumed space (V) is arranged, the inner container (100) being configured to store an inner volume (I) of fuel, in a wall of the outer container (200) a further burst element (202) being arranged, the further burst element being fluidically connected to the vacuumed space (V).

2. The pressure vessel of claim 1, wherein, the pressure vessel further comprising at least one overpressure bleed valve (177), wherein downstream of the overpressure bleed valve (177) at least one fuel converter (180) is arranged; and the pressure relief mechanism (172, 174) and the overpressure bleed valve (177) being directly fluidically connected to the inner volume (I) of the pressure vessel.

3. The pressure vessel of claim 1 or 2, wherein, the burst element (176) being arranged outside the outer container (200).

4. The pressure vessel of claim 2, wherein, the pressure relief line (171) having a first line end portion (178); and the burst element (176) and / or the overpressure bleed valve (177) being configured at the first line end portion (178).

5. The pressure vessel of claim 1 or 2, wherein, the pressure relief line (171) extending over a peripheral region of the pressure vessel.

6. The pressure vessel of claim 5, wherein, the pressure relief line (171) extending over a peripheral region of the outer container (200).

7. The pressure vessel of claim 2, wherein, the triggering pressure of the overpressure bleed valve (177) being lower than the triggering pressure of the overpressure safety valve (175) and / or lower than the triggering pressure of the burst element (176).

8. Motor vehicle, the motor vehicle comprising at least one pressure vessel according to any one of claims 1 to 7.

9. The motor vehicle of claim 8, wherein, the overpressure safety valve (175) being fluidically connected to a fuel outlet (179) arranged on a roof of the motor vehicle.

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