Compressed gas storage device, vehicle having compressed gas storage device

Abstract

The present invention relates to a compressed gas storage device (1) for mobile applications, in particular for storing hydrogen on board a vehicle, comprising at least one metallic storage housing (2) defining a storage volume (3) that can be filled with compressed gas, and at least one temperature- and / or pressure-sensitive overload valve (4) arranged in the storage housing (2). [Solution] According to the invention, the storage housing (2) or the compressed gas storage device (1) is at least partially surrounded by a thermal protection shield (5), in particular leaving the at least one overload valve (4) uncovered. The invention further relates to a vehicle equipped with a compressed gas storage device (1) for storing hydrogen according to the invention.

Description

[Technical Field]

[0001] The present invention relates to a compressed gas storage device having the features of the preamble of claim 1. The compressed gas storage device is particularly suitable for storing hydrogen on board vehicles for mobile applications, for example those powered by fuel cells. The invention therefore also relates to a vehicle comprising a compressed gas storage device according to the invention. [Background technology]

[0002] The storage of hydrogen for mobile applications, for example to power fuel cell vehicles, is technically demanding and represents a major cost driver. Basically, hydrogen can be stored at extremely low temperatures in so-called cryotanks or under pressure in one or more compressed gas vessels. For applications where continuous hydrogen withdrawal is not guaranteed, storing it under pressure, i.e. in a compressed gas storage system, is an advantageous solution.

[0003] In compressed gas storage devices for hydrogen, pressures can reach up to 700 bar. Therefore, the storage device must be designed for such high pressures. Therefore, containers or storage housings made of metal, especially steel, or high-strength carbon fiber are usually selected. In addition, carbon fiber has the advantage of being particularly light, and containers made from it have a very low weight, especially compared to steel containers. However, since the production of such containers is relatively labor-intensive and therefore more expensive, steel containers are preferred.

[0004] To provide sufficient hydrogen on-board, compressed gas storage systems typically include a large number of identical compressed gas containers, thus increasing the cost advantage as the number of containers increases.

[0005] In addition to the high storage pressure in a compressed gas storage system, external heat input causes the temperature and therefore the pressure to rise in the compressed gas container or compressed gas storage system. This in turn increases the load on the individual compressed gas containers and the associated risk of bursting. This places correspondingly high safety demands on compressed gas storage systems. For example, a compressed gas storage system with a pressure of 700 bar inside the container is therefore designed for a burst pressure significantly higher than 1000 bar in order to comply with safety demands. Additionally, for safety reasons, each container is provided with at least one temperature- and / or pressure-sensitive overload valve, which limits the pressure to the maximum permitted pressure. This is because the valve opens when the maximum pressure is reached, thus relieving the load.

[0006] Patent Document 1 discloses a compressed fuel gas container with a pressure relief device, which includes, for example, a relief valve and a pressure signal line. When a pressure signal is received, the relief valve opens, allowing gas to escape from the compressed gas container. In this way, the compressed gas container is prevented from bursting. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] German Patent Invention No. 102006009537 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention takes as its starting point the above-mentioned prior art and is based on the object of providing a compressed gas storage device for mobile applications, in particular for storing hydrogen on board a vehicle, that is designed for high pressures and at the same time has high temperature tolerances, thereby providing a compressed gas storage device that meets high safety requirements. [Means for solving the problem]

[0009] To achieve the above object, a compressed gas storage device is proposed having the features of claim 1 and a vehicle having the features of claim 9. Advantageous developments of the invention can be read from the respective dependent claims.

[0010] The proposed compressed gas storage device comprises at least one metal storage housing defining a storage volume that can be filled with compressed gas and at least one temperature- and / or pressure-sensitive overload valve arranged in the storage housing. According to the invention, the storage housing or the compressed gas storage device is at least partially surrounded by a thermal protection shield, in particular without covering the at least one overload valve.

[0011] The task of the thermal protection shield is to reduce harmful heat input from the outside to the inside, i.e., to the storage volume filled with compressed gas. In this way, a temperature increase and the associated pressure increase in the storage housing are prevented. This therefore results in an increased temperature tolerance of the individual storage housing or the compressed gas storage device as a whole.

[0012] The high temperature tolerance of the proposed compressed gas storage device allows for the use of a metal storage housing, for example, a steel storage housing. Metal storage housings typically do not have a high temperature tolerance due to the high thermal conductivity of metals, and therefore cannot typically be used in compressed gas storage devices that must meet high safety requirements without taking other safety measures. However, metal storage housings have the advantage that high storage pressures are possible due to the high strength of metals, particularly steel. Additionally, as mentioned at the beginning, the use of metal storage housings entails cost advantages.

[0013] The proposed compressed gas storage device fully utilizes the advantages of a metal storage housing, while the disadvantage of low temperature tolerance is eliminated by providing a thermal protection shield, and in addition, the proposed compressed gas storage device with at least one metal storage housing meets the high safety requirements imposed on compressed gas storage devices for mobile applications.

[0014] The heat protection shield is preferably a coating, a cover and / or a casing or comprises a coating, a cover and / or a casing.

[0015] The coating is applied directly to the outside of the storage housing, thus requiring little or no additional structural space. Another advantage of the coating is that it adheres very well to the exterior surface of the storage housing. In addition, the coating can be easily applied by spraying or spraying.

[0016] In the case of a cover, this can likewise be arranged directly on the outer surface of at least one of the storage housings, so that the cover is directly adjacent to the storage container. Alternatively, the cover can be arranged at a distance from the storage housing, for example, in order to arrange a fitting for accommodating the cover between the storage housing and the cover. If the compressed gas storage device comprises several storage housings, these can have a common cover for forming a thermal protection shield. This means that each storage container does not need to have its own thermal protection shield, which reduces the manufacturing and assembly effort. At the same time, construction space can be saved in this way.

[0017] Alternatively or additionally, the heat protection shield can be or comprise a casing. The advantage of a casing is that it does not necessarily have to be adapted to the shape of the individual storage housing and can therefore have a simple, for example rectilinear and / or angular, shape. Furthermore, one casing can easily serve as a heat protection shield for several storage housings.

[0018] The thermal protection shield of the proposed compressed gas storage device is preferably manufactured at least partially from a non-metallic material because, unlike the storage housing, the thermal protection shield does not need to meet high strength requirements since it is not exposed to high pressures within the storage volume. The function of the thermal protection shield is completely different from that of the storage housing, namely, to reduce heat input from the outside. By separating the functions between the storage housing and the thermal protection shield, materials can be selected according to their respective functions. This means that, for the thermal protection shield, a material with particularly low thermal conductivity is selected to reduce the thermal conductivity of the thermal protection shield.

[0019] The following relationship holds between thermal conductivity λ and thermal diffusivity a: a=λ / (ρ * c). Here, "ρ" represents the density and "c" represents the specific heat capacity. The thermal conductivity a therefore depends on the design and material. The thermal protection shield of the compressed gas storage device according to the invention has a thermal conductivity a<1 mm 2 For example, this can be achieved by using insulating materials, such as glass wool or rock wool, to form a thermal protection shield.

[0020] It is further proposed that the metal storage housing of the compressed gas storage device has a substantially cylindrical shape. A cylindrical storage housing is particularly suitable for high storage pressures. The storage housing can have, for example, the shape of a bottle. Alternatively or additionally, it is proposed that the storage housing has at least one domed end, in the region of which the overload valve is arranged. This means that the overload valve is arranged, in particular, on the end face. This allows for the arrangement of several storage housings directly next to each other in parallel, thereby enabling tight "packing," which is advantageous for mobile applications.

[0021] The thermal protection shield is particularly arranged in the peripheral region of the storage housing and extends over an angular range of at least 45°, preferably at least 90°, and more preferably at least 120°. For example, the thermal protection shield may be formed circumferentially, i.e., it may extend over the entire circumference of the storage housing or 360°. The location of the thermal protection shield depends, inter alia, on whether the compressed gas storage device should be protected against external heat input over a wide area or only locally. Local heat input can be caused, in particular, by a single heat source on the vehicle. Furthermore, if there are no other heat sources, protection can be limited to a local area. This means that the compressed gas storage device is only partially protected by the thermal protection shield. Since high temperatures can be reached by a single heat source on the vehicle, at least partial protection is provided. In this case, the thermal protection shield is formed or arranged at least where the heat input is greatest, because a malfunction of the compressed gas storage device, even if only localized, must be absolutely prevented.

[0022] Only localized heat input can be dangerous, especially if the location of the heat input is far from the thermally activated overload valve, because in that case the localized heat input will not be detected or will be detected only after a delay. This danger can be prevented by using at least a partial heat protection shield.

[0023] Since a thermally actuated overload valve must be able to recognize dangerous external heat sources, it is proposed to form or arrange the thermal protection shield such that at least one overload valve of the compressed gas storage device is left exposed, i.e., not covered by the thermal protection shield, for example, when the overload valve is arranged on the end face and the thermal protection shield is arranged on the outer periphery.

[0024] However, it is also possible to arrange the thermal protection shield in the region of the end face of the storage housing, which region can remain to be provided with the thermal protection shield if an overload valve is located in this region.

[0025] The thermal protection shield preferably has an inner contour that matches the outer contour of the storage housing, which allows the thermal protection shield to be constructed or arranged in a very space-saving manner. In particular, the thermal protection shield has a constant thickness, which allows the outer contour of the thermal protection shield to follow the outer contour of the storage housing.

[0026] It is further preferred that the heat protection shield abuts the entire surface of the storage housing, thereby ensuring that, for example in the event of a fire, flames do not reach between the storage housing and the heat protection shield and directly burn the storage housing.

[0027] The proposed compressed gas storage device can comprise multiple storage housings, each equipped with a thermal protection shield, so that the number of storage housings can be varied as required without requiring any changes to the thermal protection shield.

[0028] Furthermore, the proposed vehicle is characterized by being equipped with a compressed gas storage device according to the present invention for storing hydrogen. Therefore, not only the compressed gas storage device but also the vehicle meets high safety requirements. To this end, at least one metal storage housing of the compressed gas storage device allows for high storage pressures. The vehicle may be, in particular, a fuel cell vehicle, which uses a fuel cell to convert hydrogen and oxygen into electrical energy and use it to drive an electric machine. In this case, the compressed gas storage device is, in particular, a component of the vehicle's fuel cell system.

[0029] The arrangement of the compressed gas storage device in the vehicle is particularly made so that the heat protection shield of the compressed gas storage device is arranged at least in the area of ​​the outer surface of the compressed gas storage device facing the heat source of the vehicle. This means that the heat protection shield is arranged exactly where the heat input from the outside is greatest. If other heat sources in the vehicle are not dangerous, the heat protection shield can be limited to this area. However, the heat protection shield can also be designed to be larger. Furthermore, other heat protection shields can be provided.

[0030] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a schematic longitudinal cross-sectional view of a first compressed gas storage device according to the present invention; [Figure 2] 2 is a schematic longitudinal cross-sectional view of a second compressed gas storage device according to the present invention; FIG. [Figure 3] 10 is a schematic longitudinal cross-sectional view of a third compressed gas storage device according to the present invention. FIG. [Figure 4] FIG. 10 is a schematic longitudinal cross-sectional view of a fourth compressed gas storage device according to the present invention. [Figure 5] FIG. 10 is a schematic longitudinal cross-sectional view of a fifth compressed gas storage device according to the present invention. [Figure 6] FIG. 10 is a schematic longitudinal cross-sectional view of a sixth compressed gas storage device according to the present invention. [Figure 7]FIG. 10 is a schematic longitudinal cross-sectional view of a seventh compressed gas storage device according to the present invention. [Figure 8] 1 is a schematic longitudinal section of a compressed gas storage device known from the prior art; [Figure 9] 1 is a diagram showing the temperature profile of the wall of a storage housing of a compressed gas storage device known from the prior art; [Figure 10] 1 is a chart illustrating the temperature profile of a wall of a storage housing of a compressed gas storage device according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0032] 1, a first compressed gas storage device 1 according to the present invention is shown. The compressed gas storage device comprises a cylindrical metal storage housing 2 having a domed end 6 at each end. An overload valve 4 is disposed in the center of each end 6.

[0033] A cylindrical metal storage housing 2 defines a storage volume 3 for containing a gas under pressure, here hydrogen. Since the pressure in the storage volume 3 can be up to 700 bar, the temperature increase and subsequent further pressure increase due to external heat input must be prevented or at least significantly reduced. Therefore, the illustrated storage housing 2 is completely surrounded by a thermal protection shield 5 in the form of a coating, leaving the two overload valves 4 uncovered. The coating consists of a material with a significantly lower thermal conductivity than the metal of the storage housing 2, thereby reducing the thermal conductivity. As a result, the storage housing 2 is heated to a significantly lesser extent by external heat input.

[0034] Figure 2 shows another compressed gas storage device 1 according to the invention, which differs from Figure 1 in that the thermal protection shield 5 is only partially formed. The thermal protection shield does not cover both overload valves 4 nor both ends 6.

[0035] The compressed gas storage device 1 can also have only one overload valve 4, so that in this case it is possible to cover with the thermal protection shield 5 only the area of ​​the end 6 where the overload valve 4 is located. This embodiment is exemplarily shown in FIG. 3.

[0036] 4 shows an embodiment of the compressed gas storage device 1 according to the invention, in which the thermal protection shield 5 is formed by a cover for the storage housing 2. The cover completely encloses the storage housing, leaving two overload valves 4, each arranged at an end side, uncovered.

[0037] Figure 5 shows a variant with an overload valve 4 arranged only on one end face and a casing as a thermal protection shield 5. As in the embodiment of Figure 3, the casing leaves an end 6 where the overload valve 4 is arranged.

[0038] As Figures 6 and 7 show, the casing can be even less, so that only those areas that face the heat source in a specific use are protected against external heat input.

[0039] 8 shows a conventional compressed gas container having a cylindrical metallic storage housing 2 and two overload valves 4 arranged at each end. Due to the absence of a thermal protection shield 5, the inside of the storage housing 2 (the compressed gas therein) can be heated by external heat input, resulting in a pressure increase with a high risk of explosion.

[0040] In Fig. 9, the temperature profile of the wall of the storage housing 2 of the embodiment according to Fig. 8 is exemplarily shown. A Temperature T A is the inner surface A I The temperature drops very slightly across the wall thickness up to the maximum permissible temperature T max Barely lower than.

[0041] In the compressed gas storage device 1 according to the invention, heating can be significantly reduced by using a thermal protection shield 5. This is exemplarily shown in Figure 10. Due to the poor thermal conductivity of the material of the thermal protection shield 5, the temperature T A is still allowed outside the storage housing 2 at the maximum temperature T max Therefore, the outer surface A of the storage housing 2 A2 The temperature measured at the outer surface A of the thermal protection shield 5 A1 Temperature T A The temperature continues to drop across the walls of the storage housing 2, so that the temperature inside the storage housing 2 reaches T max will be significantly lower than [Explanation of symbols]

[0042] 1. Compressed gas storage equipment 2 Storage Housing 3. Storage volume 4. Overload valve 5. Heat Protection Shield 6 Domed End

Claims

1. A compressed gas storage device (1) for storing hydrogen on board a vehicle, comprising at least one metal storage housing (2) defining a storage volume (3) that can be filled with compressed gas, and at least one temperature- and / or pressure-sensitive overload valve (4) arranged in said storage housing (2), the storage housing (2) or the compressed gas storage device (1) is surrounded by a thermal protection shield (5) without covering the at least one overload valve (4); When the compressed gas storage device (1) is mounted on the vehicle, the heat protection shield (5) abuts against the storage housing (2), 1. A compressed gas storage device, characterized in that the storage housing (2) is cylindrical and has at least one domed end (6), in the region of which the overload valve (4) is arranged.

2. 2. Compressed gas storage device (1) according to claim 1, characterized in that the thermal protective shield (5) is or comprises a coating, a cover and / or a casing.

3. 3. Compressed gas storage device (1) according to claim 1 or 2, characterized in that the thermal protection shield (5) is at least partly made of non-metallic material.

4. A compressed gas storage device (1) as described in claim 3, characterized in that the non-metallic material has a thermal conductivity (a) of <1 mm 2 / s.

5. 5. The compressed gas storage device (1) according to claim 1, wherein the thermal protection shield (5) is arranged in the peripheral region of the storage housing (2) and extends over an angular range of at least 45°.

6. 6. The compressed gas storage device (1) according to claim 1, wherein the thermal protection shield (5) is arranged in the peripheral region of the storage housing (2) and extends over an angular range of at least 90°.

7. 7. The compressed gas storage device (1) according to claim 1, wherein the thermal protection shield (5) is arranged in the outer peripheral region of the storage housing (2) and extends over an angular range of at least 120°.

8. 8. Compressed gas storage device (1) according to any one of claims 1 to 7, characterized in that the thermal protection shield (5) is arranged in the region of an end face of the storage housing (2).

9. 9. Compressed gas storage device (1) according to any one of claims 1 to 8, characterized in that the thermal protection shield (5) has an inner contour adapted to the outer contour of the storage housing (2).

10. The compressed gas storage device (1) according to any one of claims 1 to 9, characterized in that the compressed gas storage device (1) comprises a plurality of storage housings (2), each of which comprises a thermal protective shield (5).

11. A vehicle comprising a compressed gas storage device (1) according to any one of claims 1 to 10 for storing hydrogen.

12. 12. Vehicle according to claim 11, characterized in that the heat protection shield (5) of the compressed gas storage device (1) is arranged at least in the area of ​​the outer surface of the compressed gas storage device (1) facing towards the heat source of the vehicle.

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