HYDROGEN GAS SUPPLY SYSTEM

Abstract

A hydrogen gas supply system for a hydrogen consuming energy converter arranged onto a vehicle comprising a plurality of tanks for storage of pressurized hydrogen gas, wherein each tank is provided with a valve configured to control the flow of hydrogen from the corresponding tank into a flow line connected to the hydrogen consuming energy converter, wherein the plurality of tanks comprises one or more primary tanks, each of which being provided with a corresponding primary hydrogen flow control valve, the plurality of tanks further comprising a secondary tank provided with a corresponding secondary hydrogen flow control valve, wherein the hydrogen gas supply system is arranged so that the secondary tank contains a smaller maximum working amount of pressurized hydrogen, and/or so that the flow of hydrogen from the secondary tank is restricted.

Claims

1. A hydrogen gas supply system for a hydrogen consuming energy converter arranged onto a vehicle, wherein the hydrogen gas supply system comprises a plurality of tanks for storage of pressurized hydrogen gas, wherein each of the plurality of tanks is provided with a valve configured to control the flow of hydrogen from the corresponding tank into a flow line connected to the hydrogen consuming energy converter, wherein the plurality of tanks comprises one or more primary tanks, each of which being provided with a corresponding primary hydrogen flow control valve, the plurality of tanks further comprising a secondary tank provided with a corresponding secondary hydrogen flow control valve, wherein the hydrogen gas supply system is arranged: so that the secondary tank contains a smaller maximum working amount of pressurized hydrogen than each of the one or more primary tanks, and/or so that the flow of hydrogen from the secondary tank is restricted so that a maximum mass flow rate of hydrogen flowing from the secondary tank into the flow line when only the secondary valve is open is smaller than the maximum mass flow rate of hydrogen flowing from each of the one or more primary tanks into the flow line when only the corresponding primary valve is open, and wherein the hydrogen gas supply system is configured to be set in at least: a first, normal operation mode wherein at least one primary valve is open, and a second, safety operation mode wherein the secondary valve is open and wherein all primary valves are closed.

2. The hydrogen gas supply system of claim 1, wherein a gas storage volume of the secondary tank is smaller than that of each of the one or more primary tanks.

3. The hydrogen gas supply system of claim 1, wherein a pressure of the hydrogen gas is lower in the secondary tank than in each of the one or more primary tanks when the primary and the secondary tanks are filled with pressurized hydrogen up to a maximum working level.

4. The hydrogen gas supply system of claim 1, wherein each of the one or more primary tanks is designed to withstand a higher internal gas pressure than the secondary tank.

5. The hydrogen gas supply system of claim 1, wherein the secondary tank is provided with a nozzle element configured to restrict the maximum mass flow rate of hydrogen flowing from the secondary tank into the flow line when the secondary valve is open.

6. The hydrogen gas supply system of claim 1, wherein the system further comprises a replenishment gas conduit arranged between the one or more primary tanks and the secondary tank so as to allow replenishment of the secondary tank with hydrogen gas flowing from the one or more primary tanks.

7. The hydrogen gas supply system of claim 6, wherein the replenishment gas conduit is provided with a replenishment valve configured to control the flow of hydrogen to the secondary tank, wherein the replenishment valve is closed when the hydrogen gas supply system is set in the second operation mode.

8. The hydrogen gas supply system of claim 1, wherein the system comprises a plurality of primary tanks.

9. The hydrogen gas supply system of claim 1, wherein the system comprises only one secondary tank.

10. The hydrogen gas supply system of claim 1, wherein the system comprises a control unit arranged to control the hydrogen gas supply system.

11. A vehicle comprising a hydrogen consuming energy converter and the hydrogen gas supply system of claim 1, wherein the hydrogen gas supply system is arranged to supply the energy converter with hydrogen.

12. The vehicle of claim 11, wherein the hydrogen consuming energy converter forms part of a drive system arranged for propulsion of the vehicle.

13. The vehicle of claim 11, wherein the hydrogen consuming energy converter is a fuel cell system or an internal combustion engine.

14. The vehicle of claim 11, wherein the hydrogen gas supply system is configured to switch between the first and the second operation modes depending on location and/or speed of the vehicle.

15. A method for operating the hydrogen gas supply system of claim 1, the method comprising: operating the hydrogen gas supply system in a first operation mode wherein at least one primary valve is open, and switching operation modes so as to operate the hydrogen gas supply system in a second operation mode wherein the secondary valve is open and wherein all primary valves are closed.

16. The method of claim 15, wherein the hydrogen gas supply system is arranged onto a vehicle, the method comprising: switching operation modes to the second operation mode in association with moving the vehicle inside a building, and operating the hydrogen gas supply system in the second operation mode when the vehicle is inside the building.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] With reference to the appended drawings, below follows a more detailed description of embodiments of the invention cited as examples.

[0038] In the drawings:

[0039] FIG. 1 shows, in a schematic view, an exemplary embodiment of a hydrogen gas supply system according to this disclosure.

[0040] FIG. 2 shows, in a schematic view, shows a vehicle provided with a hydrogen gas supply system according to this disclosure, wherein the hydrogen gas supply system forms part of a drive line of the vehicle.

DETAILED DESCRIPTION

[0041] FIG. 1 shows a hydrogen gas supply system 1 for a hydrogen consuming energy converter 2 in the form of a fuel cell stack or an internal combustion engine 2. As exemplified in FIG. 2, the hydrogen gas supply system 1 and the hydrogen consuming energy converter are intended to be arranged onto a vehicle 10 and form part of a driveline thereof.

[0042] The hydrogen gas supply system 1 comprises a plurality of tanks 21-26 for storage of pressurized hydrogen gas, and each of said plurality of tanks 21-26 is provided with a valve 31-36 configured to control the flow of hydrogen from the corresponding tank 31-36 into a flow line 3-6 connected to the hydrogen consuming energy converter 2.

[0043] The flow line comprise in this example a manifold 3 common for all tanks 21-26, a high pressure conduit 4, an intermediate conduit 5 and a low pressure conduit 6.

[0044] The hydrogen gas supply system 1 is further provided with a first outlet 51 for manual emptying of the high pressure side and the tanks, a second outlet 52 for emptying of the high pressure side and the tanks in case a pressure or temperature safety valve is opened, a communication interface 53 based on e.g. IR or Wifi for use when refilling the tanks, a connector for refilling of hydrogen 54, a first pressure gauge for high pressure side 55, a second pressure gauge for low pressure side 56, a high pressure regulator 57 and a low pressure regulator 58.

[0045] The plurality of tanks comprises in this case five primary tanks 21-25, each of which being provided with a corresponding primary hydrogen flow control valve 31-35. The plurality of tanks further comprises one secondary tank 26 provided with a corresponding secondary hydrogen flow control valve 36.

[0046] The hydrogen gas supply system 1 is arranged so that the secondary tank 26 contains a smaller maximum working amount of pressurized hydrogen than each of the five primary tanks 21-25, i.e. when all tanks 21-26 are filled up to a maximum working level, the secondary tank 26 contains a smaller amount of hydrogen than each of the primary tanks 21-25. As indicated in FIG. 1, a gas storage volume of the secondary tank 26 is smaller than that of each of the one or more primary tanks 21-25. This leads to smaller working amount of pressurized hydrogen in the secondary tank 26 than in each of the primary tanks 21-25 if the hydrogen pressure is the same in all tanks 21-26.

[0047] To further reduce the hydrogen content in the secondary tank 26, the pressure of the hydrogen gas is lower in the secondary tank 26 than in each of the primary tanks 21-25 when the primary and secondary tanks are filled with pressurized hydrogen up to the maximum working level. Each of the primary tanks 21-25 is designed to withstand a higher internal gas pressure than the secondary tank 26, which means that the secondary tank 26 can have a less sophisticated design and thus be manufactured in a less costly way.

[0048] The hydrogen gas supply system 1 is further arranged so that the flow of hydrogen from the secondary tank 26 is restricted so that a maximum mass flow rate of hydrogen flowing from the secondary tank 26 into the flow line 3-6 when only the secondary valve 36 is open is smaller than the maximum mass flow rate of hydrogen flowing from each of the one or more primary tanks 21-25 into the flow line when only the corresponding primary valve 31-35 is open. This is achieved by providing the secondary tank 26 is provided with a nozzle element 27 configured to restrict the maximum mass flow rate of hydrogen flowing from the secondary tank 26 into the flow line 3-6 when the secondary valve 36 is open. That is, the nozzle element 27 restricts the outflow from the secondary tank 26 more than the outflow is restricted from the primary tanks 21-25.

[0049] The hydrogen gas supply system 1 further comprises a control unit 8 arranged to control the system. The control unit 8 is connected to various hydrogen, temperature and pressure sensors and is capable of controlling e.g. opening and closing of the valves 31-36 based on sensor signals and other control signals. The control unit 8 is further connected to a vehicle control unit 9 configured to, for instance, provide the gas supply system control unit 8 with vehicle information, such as speed and location, and control the hydrogen consuming energy converter 2. The two control units 8, 9 may form part of one common control circuitry.

[0050] The hydrogen gas supply system 1 is configured to be set in at least i) a first, normal operation mode wherein at least one primary valve 31-35 is open and ii) a second, safety operation mode wherein the secondary valve 36 is open and wherein all primary valves 31-35 are closed. The switching of mode is controlled by the supply system control unit 8. In other embodiments, switching of modes may alternatively be carried out manually using e.g. needle valves.

[0051] The first mode is used during normal operation, such as normal operation of a vehicle where the hydrogen consuming energy converter 2 provides vehicle driving power (electrical power if the converter is a fuel cell or mechanical power if the converter is an internal combustion engine). The control unit 8 may be configured to keep only one primary valve 31-35 open simultaneously when operating in the first mode so as to reduce leakage of hydrogen if leakage occurs during operation according to the first mode.

[0052] The second mode is used when there is of particular importance that a significant leakage of hydrogen is avoided, such as when a vehicle provided with the system shown in FIG. 1 is inside a building. When the hydrogen gas supply system 1 is operated in this second mode, the safety mode, the maximum amount of hydrogen that can leak from the flow line 3-6 is set by the maximum working amount of hydrogen in the secondary tank 26, which is less than the maximum working amount of hydrogen in each of the primary tanks 21-25. Thus, switching to the second mode reduces the amount of hydrogen that may be released if leakage occurs.

[0053] In addition, since the maximum mass flow rate of hydrogen from the secondary tank 26 is restricted and lower than from each of the primary tanks 21-25, also the potential maximum leakage rate from the flow line 3-6 is reduced when switching to the second mode. Whether the leakage amount or leakage rate is of highest importance may depend on the size and/or ventilation capacity of the building inside which the vehicle is (to be) located.

[0054] As shown in FIG. 1, the hydrogen gas supply system 1 further comprises a replenishment gas conduit 40 arranged between one of the primary tanks 25 and the secondary tank 26 so as to allow replenishment of the secondary tank 26 with hydrogen gas flowing from the primary tank 25. The replenishment gas conduit 40 is provided with a replenishment valve 41 configured to control the flow of hydrogen to the secondary tank 26. The replenishment valve 41 is closed when the hydrogen gas supply system 1 is set in the second operation mode.

[0055] FIG. 2 shows a vehicle 10 comprising a hydrogen consuming energy converter 2 and a hydrogen gas supply system 1 according to above, where the hydrogen gas supply system 1 is arranged to supply the energy converter 2 with hydrogen. The hydrogen gas supply system 1 and the hydrogen consuming energy converter 2 form part of a drive system arranged for propulsion of the vehicle 10. In the schematic example shown in FIG. 2 the hydrogen consuming energy converter 2 is intended to indicate a fuel cell stack providing electricity to an electric motor 11 that rotates driving wheels 12. FIG. 2 can alternatively be considered to illustrate a hydrogen gas supply system 1 feeding hydrogen to an internal combustion engine 2 that is connected to the driving wheels 12 via transmission 11.

[0056] The hydrogen gas supply system 1 may be configured to switch between the first and second operation modes depending on location and/or speed of the vehicle 10. For instance, the vehicle control unit 9 may send vehicle positioning data, such as GPS data, to the gas supply system control unit 8 indicating, together with map data accessible for the system control unit 8, that the vehicle 10 is about to enter a building 13, such as a vehicle workshop. As a response, the gas supply system control unit 8 may set the hydrogen gas supply system 1 in the second mode. When the vehicle 10 has exited the building and has reached a certain threshold speed, the supply system control unit 8, based on e.g. speed information from the vehicle control unit 9, may set the hydrogen gas supply system 1 in the first mode. Switching of modes may alternatively be done manually by e.g. a driver of the vehicle.

[0057] A method for operating the hydrogen gas supply system 1 according to above may comprise the following steps: [0058] operating the hydrogen gas supply system 1 in the first operation mode wherein at least one primary valve 31-35 is open, and [0059] switching operation mode so as to operate the hydrogen gas supply system 1 in the second operation mode wherein the secondary valve 36 is open and wherein all primary valves 31-35 are closed.

[0060] When the hydrogen gas supply system 1 is arranged onto the vehicle 10, the method may comprise: [0061] switching operation mode to the second operation mode in association with moving the vehicle 10 inside the building 13; and [0062] operating the hydrogen gas supply system 1 in the second operation mode when the vehicle 10 is inside the building 13.

[0063] It is to be understood that the present invention is not limited to the embodiments described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims.

[0064] For instance, it is not necessary that the secondary tank 26 is both smaller (i.e. has a smaller gas storage volume) and has a lower maximum working pressure than the primary tanks 21-25. Neither is it necessary that the secondary tank both contains a smaller amount of hydrogen than the primary tanks and has a more restricted outflow. However, combining these safety measures improves the safety, as exemplified by the system shown in FIG. 1.