Tank device for temperature pressure relief of a fuel cell tank

Description

[0001] The invention relates to a tank device for temperature pressure relief of a fuel cell tank, in particular for storing hydrogen, for example for use in vehicles with fuel cell drive. State of the art

[0002] DE 10 2017 212 485 A1 describes a device for storing compressed fluids used as fuel for a vehicle, wherein the device comprises at least two tubular tank modules and at least one high-pressure fuel distributor with at least one integrated control and safety technology. Furthermore, the at least two tubular tank modules are made of metal and are connected to the at least one high-pressure fuel distributor with at least one integrated control and safety technology in a modular manner to form a module with a flexible geometry.

[0003] The safety devices for such a device, as shown in DE 10 2017 212 485 A1, are standardized. Each tank module must have an automatically shut-off overflow valve and a safety valve. For example, the overflow valve can close in the event of an accident involving the compressed fluid storage device or a rupture of a line within the device, preventing gas from escaping from the storage unit. Furthermore, the safety valve should ensure, for example, in the event of a fire or a temperature increase above a predetermined threshold, that hydrogen can be removed from the tank module, preventing an explosion of the tank module or even the entire compressed fluid storage device.

[0004] These safety precautions require a large number of valves, increasing the complexity and cost of the entire gas storage system. Furthermore, depending on the position of the safety valve, it must be ensured that it is triggered even if the fire source is not near the safety valve, to prevent a possible explosion of the gas storage system.

[0005] From DE 10 2018 116090 A1, a high-pressure vessel unit is known, wherein the high-pressure vessel unit includes: a plurality of cylindrical vessels lined up inside a housing, wherein end portions of the vessels are provided with openings on one side in their axial direction; a coupling element connected to the openings of the vessels for coupling the plurality of vessels and including a flow passage communicating the interiors of the vessels; a discharge line led from the coupling element through a through hole formed in the housing to the exterior of the housing; securing elements securing the coupling element to the housing;and a holding mechanism that holds portions of the containers on the other axial direction side from the end portions on one side in the axial direction such that those portions of the containers on the other axial direction side are movable relative to the housing in the axial direction;

[0006] From DE 10 2018 116090 A1, a high-pressure tank mounting structure is known, which includes a housing arranged under a floor of a vehicle cabin and having a bottom wall, a peripheral wall, and an upper wall; a plurality of high-pressure tanks accommodated in such a manner as to be lined up in the housing; and a discharge hole formed at an upper portion of the housing and discharging hydrogen that has penetrated from the high-pressure tanks to an exterior of the housing.

[0007] DE 10 2018 116090 A1 discloses a tank device for thermal pressure relief of a fuel cell tank. The tank device comprises at least two tank containers and a supply line connectable to the tank containers. Each tank container comprises at least one pressure-controlled overflow valve, wherein the overflow valve is arranged between the respective tank container and the supply line. Furthermore, a central shut-off valve is arranged in the supply line.

[0008] From US 2020 / 191335 A1, a high-pressure container unit is known, comprising: a container body configured to store high-pressure gas; a housing that stores the container body inside the housing; a pipe connected to the container body and extending to an outside of the housing; and a closure member configured to close the pipe and allow the high-pressure gas stored in the container body to be discharged from the pipe when a given condition is met.

[0009] US 6 418 962 B1 shows a fuel storage system for compressed gas vehicles, which consists of a plurality of compressed gas pressure cells supported by shock-absorbing bumpers. Advantages of the invention

[0010] The tank device according to the invention with the characterizing features of claim 1 has the advantage that a local heat source on the tank device is quickly and reliably detected in a structurally simple manner in order to ensure reliable opening of the safety valves.

[0011] For this purpose, the tank device for temperature pressure relief of a fuel cell tank comprises at least two tank containers and a supply line connectable to the tank containers. Each of the at least two tank containers has at least one shut-off valve at one end, which shut-off valve is arranged between the respective tank container and the supply line. At least one safety valve is also arranged at another end of the tank container. Furthermore, at least the at least two tank containers and the respective safety valve are at least almost completely enclosed by a frame-shaped housing element and / or are encapsulated from the environment, in particular in a pressure-tight manner. In this case, an overpressure prevails in the housing element, in particular an interior space, in particular relative to the environment and / or to an ambient pressure.The housing element comprises a temperature-sensitive material, in particular plastic, wherein the temperature-sensitive material has a melting temperature below the melting temperature of the material of the tank container and wherein the safety valve opens when the pressure prevailing in the interior drops, in particular the overpressure.

[0012] This ensures that the respective safety valve opens safely in an emergency, such as an accident involving a fire, to release the stored hydrogen from the tank containers and thus prevent the tank containers from bursting. This is regardless of the location of the heat input to the tank device, since heat input to the housing element creates a pressure drop inside the housing element, particularly the overpressure, which can trigger the safety valves. The frame-shaped housing element covers a large area of ​​the vehicle, which triggers the safety valves in the event of a fire.Furthermore, this approach can provide the advantage of ensuring that the material of the housing element melts and thus the pressure within the housing element drops, causing the safety valve to open and release the hydrogen from the at least one tank before the material of the at least one tank fails and the tank can burst. This can prevent an explosion and / or bursting of the tank, particularly in the event of an accident and / or fire in the entire vehicle.

[0013] In a first advantageous embodiment, the safety valve comprises a meltable medium, such as wax, so that it is, in particular, a meltable safety valve. This allows for a cost-effective and compact design of the safety valve, which reliably opens once in the event of an emergency, thus allowing the hydrogen to be discharged from the area of ​​the respective tank.

[0014] In a further embodiment of the invention, it is advantageously provided that the fusible medium of the safety valve melts when the ambient temperature increases, thus opening the safety valve. In this way, it can be ensured that in the event of an emergency in which a temperature increase occurs in the area of ​​the vehicle and / or the tank, for example due to a fire, the fusible medium is heated, whereby the state of matter changes from at least almost solid to at least almost liquid and the fusible medium moves out of the area of ​​the safety valve, in particular a neck area, and thus the hydrogen stored in the tank container can be released from it and then discharged into the environment via a discharge line and / or a drain valve.This allows hydrogen to be channeled from the tank containers into the discharge line in a simple and safe manner, preventing the tank containers from bursting, particularly to prevent the risk of explosion in the tank and thus in the entire vehicle. In an advantageous further development, the respective safety valve has a pressure sensor which, when the pressure in the interior changes, activates a heating element that heats the fusible medium of the safety valve. This ensures that, when the pressure in the interior drops, the fusible medium changes to an at least nearly liquid state, thus opening the safety valve by melting the fusible medium, allowing the hydrogen to be discharged from the tank.

[0015] In an advantageous development, it is provided that at least one valve, which is in particular a pressure relief valve, is located on at least one of the at least two tank containers, wherein the valve leads to a continuous discharge of the hydrogen from the respective tank container into the interior. In this way, the advantage can be achieved that a leak that may occur at the housing element, in which in particular only a small amount, such as less than 1% by weight of the gas located in the interior of the housing element, escapes per hour, can be compensated for by the gas located in the respective tank container, and thus the pressure in the interior of the housing element does not drop and / or can at least be almost maintained.This prevents the safety valve from being opened incorrectly and unintentionally, particularly when there is no emergency, such as an accident involving a fire, and prevents hydrogen from being released from the tank without an emergency.

[0016] In an advantageous development, each tank container can be connected to the discharge line by means of a respective safety valve. This ensures that each tank container has its own safety valve, which at least allows the hydrogen from the other tank containers to be drained in the event of a safety valve malfunction.

[0017] The tank device described is preferably suitable in a fuel cell system for storing hydrogen for the operation of a fuel cell.

[0018] In advantageous applications, the tank device can be used in vehicles with a fuel cell drive. Drawings

[0019] The drawing shows exemplary embodiments of a tank device according to the invention for temperature pressure relief of a fuel cell tank. Fig. 1 a schematic plan view of a tank device according to the invention, Fig. 2 a plan view of the tank device according to the invention with at least two tank containers and a surrounding frame-shaped housing element, Fig. 3 a side view of the tank device according to the invention with at least two tank containers and the surrounding frame-shaped housing element, Fig. 4 a sectional view of a safety valve.

[0020] All figures are merely schematic representations of a tank device according to the invention, the method according to the invention, or its components according to exemplary embodiments of the invention. In particular, distances and size relationships are not shown to scale in the figures. Description of the embodiments

[0021] Fig. 1 shows an embodiment of a tank device 1 according to the invention in a plan view. The tank device 1 has several tank containers 2, which are essentially cylindrical and made of steel.

[0022] According to the illustration Fig. 1 is a schematic plan view of the tank device 1 according to the invention for a fuel cell system 31. The tank device 1 has at least two tank containers 2 for storing hydrogen, as well as a frame-shaped housing element 24 and a supply line 4 connectable to the tank containers 2. The frame-shaped housing element 24 at least partially surrounds the at least two tank containers 2 and the supply line 4, the at least two tank containers 2 running parallel to a longitudinal axis 9. Each of the at least two tank containers 2, which are essentially cylindrical and made of steel, has at least one valve 8, 10. This at least one valve 8, 10 is a shut-off valve 8 and / or a safety valve 10.

[0023] In an exemplary embodiment of the tank device 1, the at least two tank containers 2 each have the shut-off valve 8 at a first end 20 and the safety valve 10 at a second end 21, wherein the respective ends 20, 21 are located in the direction of the longitudinal axis 9 on the respective tank container 2. The two tank containers 2 are designed at least approximately tubular.

[0024] Furthermore, Fig. 1 It is shown that the shut-off valve 8 is arranged between the respective tank container 2 and the supply line 4, wherein the supply line 4 connects the respective tank containers 2 to the fuel cell system 31, in particular a fuel cell 29. In an exemplary embodiment of the fuel cell system 31, the hydrogen from the tank device 1, which is in particular under a high pressure of at least almost 700 bar, can reach a nozzle and / or an intake area of ​​a jet pump of the fuel cell system 31 via the supply line 4. In addition, a supply valve 5 can be located in the area of ​​the supply line 4, in particular between the shut-off valve 8 and the fuel cell system 31, in particular an anode area of ​​the fuel cell system 31 and / or at least indirectly with the fuel cell 29. The supply valve 5 can be located inside or outside the frame-shaped housing element 24.

[0025] In the region of the second end 21 of the respective tank container 2, on which the tank container 2 has the safety valve 10, the tank container 2 is connected to a connecting line 11 via the safety valve 10. The connecting line 11 serves to guide hydrogen from the respective tank container 2 out of the tank device 1 in the event of an accident and / or fire, thus counteracting a bursting of the respective tank container 2. At the end of the connecting line 11 facing away from the safety valve 10 and / or the tank container 2, in particular its downstream end, there can be a drain valve 12 via which, in the event of an accident or fire, the hydrogen can be drained into an environment 190 of the vehicle, in particular into an area where igniting hydrogen can no longer damage or injure the entire vehicle and the occupants.In a further exemplary embodiment of the tank device 1, each respective tank container 2 can be connected to a discharge line 11 by means of a respective safety valve 10.

[0026] In an exemplary embodiment, the safety valve 10 can be a so-called fusible safety valve 10 and / or a TPRD (Thermal Pressure Relief Device) valve 10, which comprises a melting medium such as wax, in order to trigger the opening of the safety valve 10 by melting the wax in the event of heat being introduced into the tank container 2. Thus, in this exemplary embodiment, the respective tank container 2 is connected with its first end 20 to the supply line 4 via the shut-off valve 8 and / or with its second end 21 to the connecting line 11 via the safety valve 10, which is designed in particular as a fusible safety valve 10.

[0027] Furthermore, a further valve may be located in the area of ​​the connecting line 11, in particular between the safety valve 10 and the drain valve 12. This further valve and / or the drain valve 12 may be located inside or outside the frame-shaped housing element 24.

[0028] The respective ends 20, 21 of the respective tank container 2 have a conical taper and thus a typical bottle neck structure.

[0029] The Fig. 1 The tank device 1 shown serves to relieve the temperature pressure of a fuel cell tank. According to the invention, at least the at least two tank containers 2 and the respective safety valve 10 are at least almost completely enclosed by the housing element 24 and / or encapsulated relative to the environment 190, in particular in a pressure-tight manner. In the housing element 24, in particular the interior 180, there is an overpressure 181, in particular relative to the environment 190 and / or to an ambient pressure 191. The pressure difference between the overpressure 181 in the interior 180 can, for example, be at least 0.1 bar compared to the ambient pressure 191 of the environment 190, whereby the environment 190 can also be the environment 190 outside the entire vehicle. The housing element 24 comprises at least one temperature-sensitive material 25, in particular plastic.A fusible medium 71 of the safety valve 10 can melt if the pressure prevailing in the interior 180, in particular the overpressure 181, drops, thus opening the safety valve 10. The mechanism of action is that in the event of a fire or a temperature increase due to an accident in the area of ​​the tank device 1 and / or the entire vehicle, a temperature increase occurs at any point in the housing element 24 such that the temperature-sensitive material 25 melts, thus creating an opening in the housing element 24 through which the gaseous medium escapes from the interior 180, in particular into the environment 190, and thus the overpressure 181 decreases and at least nearly equalizes to the ambient pressure 191.Due to the pressure drop in the interior 180, the safety valve 10 now opens, at least indirectly, and guides the hydrogen contained in the tank container 2 out of the tank device 1 via the discharge line 11 and the drain valve 12, so that the hydrogen is harmless to the tank device 1 and the entire vehicle, for example, due to a fire triggered by an accident. Advantageously, due to the inventive design of the tank device 1, the safety valve 10 does not only trigger when it opens directly at the safety valve 10 due to the temperature input of the fire, but rather the area in which a temperature input due to a fire leads to the opening of the safety valve 10 is enlarged, for example, in the area of ​​the entire frame-shaped housing element 24.Thus, the hydrogen can be discharged from the respective point in time earlier, before it reaches the safety valve 10 and / or the respective tank container 2. This reduces the risk of a serious accident caused by the fire ignited by hydrogen and / or a bursting of the tank containers 2, since the hydrogen can be discharged from the tank device 1 and / or the entire vehicle much earlier.

[0030] The tank device 1 functions as follows: When the fuel cell system 31 is functioning properly, the fuel cell 29 is supplied with hydrogen from the tank containers 2. The shut-off valves 8 are designed to ensure a reliable supply to the fuel cell 29.

[0031] If heat is introduced into the tank device 1 or the tank containers 2, for example, caused by a fire, the safety valves 10 should be triggered as quickly as possible after the heat input occurs so that the hydrogen can be diverted from the tank containers 2, for example to prevent an explosion of the tank containers 2. In this case, the power supply to the shut-off valves 8 is usually also interrupted so that no more hydrogen can escape from the tank containers 2.

[0032] In order to ensure that the safety valves 10 also trigger when, for example, heat is not introduced in the vicinity of the safety valves 10, for example, heat is introduced at the first end 20 of the tank container 2, the inventive design of the tank device 1 with the overpressure 181 within the housing element 24 ensures reliable opening of the safety valves 10.

[0033] Fig. 2 shows a plan view of the tank device 1 according to the invention with at least two tank containers 2 and the surrounding frame-shaped housing element 24. In an exemplary embodiment of the tank device 1, the respective safety valves 10 can be located at a geodetically lowest point of the tank device 1. The safety valve 10 comprises the meltable medium 71, such as wax 71, so that it is in particular a melt safety valve 10. Furthermore, the meltable medium 71 of the safety valve 7 melts when the temperature of the environment 190 increases, whereby the safety valve 10 opens. The frame-shaped housing element 24 comprises the temperature-sensitive material 25, wherein the melting temperature of the temperature-sensitive material 25 is below the melting temperature of the material of the respective tank container 2.

[0034] Furthermore, in Fig. 2 shown that at least one valve 13, which is in particular a pressure relief valve 13, is located on at least one of the at least two tank containers 2, wherein the valve 13 leads to a continuous discharge of the hydrogen from the respective tank container 2 into the interior space 180. In the event of a possible leak at the housing element 24, in which a small amount of the gas located in the interior space 180 escapes into the environment 190, this can be compensated for by the gas located in the tank container 2 being guided into the interior space 180 via the valve 13. This prevents the excess pressure 181 from dropping when there is no accident and / or fire, which would trigger the safety valve 10. This can be the case in particular if there is a leak due to a small puncture of the housing element 24. The pressure level within the interior space 180 is maintained.

[0035] Fig. 3 shows a side view of the tank device 1 according to the invention with at least two tank containers 2 and the surrounding frame-shaped housing element 24. It is shown that the tank containers 2 are arranged next to one another in a plane, wherein the housing element 24 surrounds the tank containers 2 and an overpressure 181 is formed in the interior 180 of the housing element 24, in particular relative to the ambient pressure 191.

[0036] In Fig. 4An exemplary embodiment of the tank device 1 and / or the safety valve 10 is shown in which the respective safety valve 10 has a pressure sensor 72 which, upon a pressure change in the interior 180, activates a heating element 73 which heats the fusible medium 71 of the safety valve 10. The sensor 72 is connected to the heating element 73, for example by means of cabling. As soon as the pressure, in particular overpressure 181, in the interior 180 falls below a limit value, the sensor 72 controls the heating element 73 and / or supplies the heating element 73 with energy. The fusible medium 71 then melts due to the temperature input, flows away, in particular in the direction of a discharge line 11, and thus the safety valve 10 opens, so that the hydrogen can escape from the tank container 2.The heating element 73 can be designed in a sleeve-like manner around a central axis 6, thus the meltable medium 71 is located inside the heating element 73.

[0037] The opening of the respective safety valve 10 is irreversible in all embodiments, since in the event of a fire the tank containers 2 are emptied quickly and efficiently and to ensure complete emptying the safety valve 10 should remain in the open state.

Claims

1. Tank apparatus (1) for temperature pressure relief of a fuel cell tank, the tank apparatus (1) comprising at least two tank vessels (2) and a feed line (4) which can be connected to the tank vessels (2), each of the at least two tank vessels (2) having, at one end (20), at least one shut-off valve (8), which shut-off valve (8) is arranged between the respective tank vessel (2) and the feed line (4), at least one safety valve (10) being arranged at another end (21) of the tank vessel (2), characterized in that at least the at least two tank vessels (2) and the respective safety valve (10) are enclosed at least approximately completely by a housing element (24) and / or are encapsulated, in particular in a pressure-tight manner, with respect to a surrounding area (190), a positive pressure (181), in particular with respect to the surrounding area (190) and / or with respect to an ambient pressure (191), prevailing in the housing element (24), in particular an interior space (180), the housing element (24) comprising a temperature-sensitive material (25), in particular plastic, the temperature-sensitive material (25) having a melting temperature below the melting temperature of the material of the tank vessel (2), and the safety valve (10) opening in the case of the pressure which prevails in the interior space (180), in particular the positive pressure (181), dropping.

2. Tank apparatus (1) according to Claim 1, characterized in that the safety valve (10) comprises a fusible medium (71) such as, for example, wax (71), with the result that this is, in particular, a fusible safety valve (10).

3. Tank apparatus (1) according to Claim 1 or 2, characterized in that the fusible medium (71) of the safety valve (10) melts in the case of a temperature increase of the surrounding area (190), and therefore opens the safety valve (10).

4. Tank apparatus (1) according to Claim 1 or 2, characterized in that the respective safety valve (10) comprises a pressure sensor (72) which, in the case of a pressure change in the interior space (180), activates a heating element (73) which heats the fusible medium (71) of the safety valve (10).

5. Tank apparatus (1) according to Claim 1, characterized in that at least one valve (13), which is, in particular, a pressure relief valve (13), is situated on at least one of the at least two tank vessels (2), the valve (13) leading to a continuous discharge of the hydrogen from the respective tank vessel (2) into the interior space (180).

6. Tank apparatus (1) according to Claim 1, characterized in that each respective tank vessel (2) can be connected by means of the respective safety valve (10) to a discharge line (11).

7. Fuel cell system (31) with a tank apparatus (1) according to one of the preceding claims.

8. Fuel cell-operated vehicle with a tank apparatus (1) according to one of Claims 1 to 6.