Hydrogen supply system

Abstract

To provide a hydrogen supply system that can supply hydrogen to a working machine in various places, and can restrain a decrease in work efficiency caused by supply work of hydrogen.SOLUTION: A hydrogen supply system comprises: a construction machine 2 using hydrogen as fuel, and to be driven by the hydrogen; a mobile hydrogen station 1 comprising a (high-pressure) hydrogen tank 3 for storing the hydrogen in a high-pressure state; and a hydrogen supply pipe 8 for connecting the construction machine 2 and the mobile hydrogen station 1. The mobile hydrogen station 1 decompresses the hydrogen stored in the (high-pressure) hydrogen tank 3, generates decompressed hydrogen, and supplies the decompressed hydrogen to the construction machine 2 via the hydrogen supply pipe 8. The construction machine 2 is driven by the decompressed hydrogen supplied from the mobile hydrogen station 1.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a hydrogen supply system, and more particularly to a hydrogen supply system including a work machine that operates using power supplied from a fuel cell and a hydrogen supply device that supplies hydrogen to the work machine. [Background technology]

[0002] In recent years, attempts have been made to install fuel cells (FCs), which are environmentally friendly power generators, in automobiles, work machinery, and other vehicles. The most common method of supplying hydrogen to vehicles equipped with fuel cells is to supply pressurized hydrogen (approximately 70 MPa to 80 MPa) to the vehicle's hydrogen tank at a stationary hydrogen station such as a gas station. There are also mobile hydrogen stations that are equipped with a hydrogen tank and hydrogen supply device on trailers or other vehicles, so that hydrogen can be supplied to areas where there are no stationary hydrogen stations.

[0003] Patent Document 1 discloses a mobile hydrogen supply facility that includes a hydrogen release pipe branching off from a hydrogen supply pipe, a gas-actuated safety valve that closes the hydrogen release pipe, a working gas supply pipe that supplies the gas-actuated safety valve with working gas that operates the gas-actuated safety valve, and one or more thermally actuated safety valves that are arranged around the accumulator and close the working gas supply pipe. In this mobile hydrogen supply facility, when the temperature around the accumulator rises to a specific temperature, the thermally actuated safety valve opens the working gas supply pipe, and working gas is supplied to the gas-actuated safety valve via the working gas supply pipe, causing the gas-actuated safety valve to open the hydrogen release pipe and release hydrogen from the accumulator to the outside via the hydrogen release pipe. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-97880 Summary of the Invention [Problem to be solved by the invention]

[0005] However, care must be taken when handling flammable gases such as hydrogen, and various safety measures are necessary, with the development of related legislation (such as the High-Pressure Gas Safety Act) underway. Therefore, in order to supply hydrogen to work machinery in various locations, it is desirable to supply it not at high pressure, but at low pressures of, for example, less than 1 MPa, which is not subject to the regulations of the High-Pressure Gas Safety Act. On the other hand, if the supplied low-pressure hydrogen is stored in a hydrogen tank and the work machinery is operated using low-pressure hydrogen stored in the hydrogen tank, the volume of hydrogen required for one day of work, for example, would be very large. This would require frequent hydrogen supply, which could result in reduced work efficiency.

[0006] The present invention aims to provide a hydrogen supply system that enables hydrogen to be supplied to work machines in various locations and that can suppress a decrease in work efficiency due to the hydrogen supply work. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides a hydrogen supply system comprising a work machine that uses hydrogen as fuel and is powered by hydrogen, a mobile hydrogen supply device having a hydrogen tank that stores hydrogen at high pressure, and hydrogen supply piping that connects the work machine to the hydrogen supply device, wherein the hydrogen supply device reduces the pressure of hydrogen stored in the hydrogen tank to produce reduced-pressure hydrogen and supplies the reduced-pressure hydrogen to the work machine via the hydrogen supply piping, and the work machine is powered by the reduced-pressure hydrogen supplied from the hydrogen supply device. In this case, it is possible to supply hydrogen to the work machine in various locations and to prevent a decrease in work efficiency due to the work of supplying hydrogen.

[0008] Here, for example, the hydrogen supply device supplies the reduced-pressure hydrogen to a plurality of the work machines, and in this case, a single mobile hydrogen supply device can operate a plurality of work machines simultaneously. Furthermore, for example, the work machine has an upper rotating body and a lower traveling body, the upper rotating body or the lower traveling body is provided with a rotary joint, the hydrogen supply piping is connected to the rotary joint, and the reduced-pressure hydrogen supplied from the hydrogen supply device is supplied to the work machine via the rotary joint. In this case, it is possible to prevent the upper rotating body and the hydrogen piping for supplying hydrogen from the hydrogen supply device to the work machine from becoming tangled. Furthermore, for example, the work machine is provided with a fuel cell as a power source, and the work machine has a storage tank for storing the reduced-pressure hydrogen supplied by the hydrogen supply device, and the reduced-pressure hydrogen supplied from the hydrogen supply device is supplied to the fuel cell and also to the storage tank. In this case, even if hydrogen cannot be supplied from the hydrogen supply device, hydrogen can be supplied from the storage means. In addition, for example, if the hydrogen supply device is divided into a container part that carries hydrogen and a towing part that tows the container part, then when refueling with hydrogen, it is only necessary to replace the container part, which can reduce time and simplify the work. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a hydrogen supply system that enables hydrogen to be supplied to work machines in various locations and that can suppress a decrease in work efficiency due to the hydrogen supply work. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a first example of a hydrogen supply system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing a second example of the hydrogen supply system according to the present embodiment. [Figure 3] FIG. 10 is a diagram showing a third example of the hydrogen supply system according to the present embodiment. [Figure 4] FIG. 10 is a diagram showing a fourth example of the hydrogen supply system according to the present embodiment. [Figure 5]FIG. 10 is a diagram showing a fifth example of the hydrogen supply system according to the present embodiment. [Figure 6] FIG. 10 is a diagram showing a sixth example of the hydrogen supply system according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0012] FIG. 1 is a diagram showing a first example of a hydrogen supply system according to the present embodiment. The illustrated hydrogen supply system comprises a mobile hydrogen station 1, which is an example of a mobile hydrogen supply device having a hydrogen tank (high pressure) 3 that stores hydrogen at high pressure, a construction machine 2, which is an example of a work machine that uses hydrogen as fuel and is powered by hydrogen, and a hydrogen supply pipe 8 that connects the construction machine 2 to the mobile hydrogen station 1 and supplies low-pressure hydrogen from the mobile hydrogen station 1 to the construction machine 2. In this case, low-pressure hydrogen is supplied from the mobile hydrogen station 1 to the construction machine 2 through the hydrogen supply pipe 8. The hydrogen supply pipe 8 is, for example, a flexible hose.

[0013] The mobile hydrogen station 1 is a vehicle capable of supplying hydrogen, and is shown as a fuel cell vehicle (FCV) in Fig. 1. However, the vehicle is not limited to this, and may be a truck or trailer powered by fossil fuel, as long as it is capable of supplying hydrogen. The mobile hydrogen station 1 includes a hydrogen tank (high pressure) 3, a hydrogen tank (low pressure) 5, a connector 7, and an FC system (for operating an FCV) 21.

[0014] High-pressure hydrogen is stored in the hydrogen tank (high pressure) 3. In this case, the pressure of the hydrogen is, for example, about 70 MPa to 80 MPa, as described above. The hydrogen tank (low pressure) 5 stores low-pressure hydrogen. In this case, the pressure of the hydrogen is, as described above, for example, less than 1 MPa. The connector 7 connects to a hydrogen supply pipe 8 and sends low-pressure hydrogen to the construction machine 2 . The FC system (for operating the FCV) 21 includes a fuel cell for propelling the mobile hydrogen station 1.

[0015] The hydrogen tank (high pressure) 3 and the hydrogen tank (low pressure) 5 are connected by a hydrogen pipe 15. The hydrogen pipe 15 is provided with a pressure adjusting valve (pressure reducing valve) 4, which reduces the pressure of the high-pressure hydrogen in the hydrogen tank (high pressure) 3 to low-pressure hydrogen (reduced pressure hydrogen), which is sent to the hydrogen tank (low pressure) 5. The hydrogen tank (low pressure) 5 and connector 7, and the hydrogen tank (low pressure) 5 and FC system 21 are connected by hydrogen piping 16. The hydrogen piping 16 is provided with a valve 6 and a valve 20. The valve 6 controls the amount of reduced pressure hydrogen supplied from the hydrogen tank (low pressure) 5 to the connector 7. The valve 20 controls the amount of reduced pressure hydrogen supplied from the hydrogen tank (low pressure) 5 to the FC system 21.

[0016] Here, a hydraulic excavator is shown as an example of the construction machine 2. In this case, the hydraulic excavator includes a lower traveling body 51 equipped with tracks for traveling the hydraulic excavator, a rotatable upper rotating body 52 attached to the lower traveling body 51, a boom 53 rotatably connected to one end of the upper rotating body 52 with a pin, an arm 54 rotatably connected to one end of the boom 53 with a pin, and a bucket 55 rotatably connected to one end of the arm 54 with a pin. Note that the construction machine 2 is not limited to a hydraulic excavator, and may be a wheel loader, a bulldozer, a crane truck, or the like.

[0017] The construction machine 2 includes a connector 9, a FC (Fuel Cell) 10, a secondary battery 19, an inverter / motor 11, an actuator 12, a controller 13, and a control panel (lever, key SW (switch), etc.) 14.

[0018] The connector 9 connects to the hydrogen supply pipe 8 and introduces the reduced pressure hydrogen sent from the mobile hydrogen station 1 into the construction machine 2 . The FC10 is a fuel cell that uses hydrogen as fuel and serves as a power source, supplying electricity to loads including a motor. The secondary battery 19 can store electricity using surplus power generated by the FC 10, and functions as a power source together with the FC 10. Here, the secondary battery 19 may be any chargeable and dischargeable power storage device, and may be configured, for example, by a lithium ion battery or a nickel-metal hydride battery. The inverter / motor 11 includes an inverter and a motor. The inverter converts a DC voltage supplied from the FC 10 or the secondary battery 19 into an AC voltage and controls the rotation speed of the motor.

[0019] The actuator 12 is a hydraulic actuator and is operated by a hydraulic circuit (not shown). The hydraulic circuit includes a hydraulic pump driven by a motor, and the hydraulic pump draws hydraulic oil and supplies the hydraulic oil via multiple control valves to operate the actuator 12. When the actuator 12 operates, the upper rotating body 52, boom 53, arm 54, and bucket 55 of the hydraulic excavator are operated. The controller 13 is a host controller that controls the entire system of the hydraulic excavator. The controller 13 outputs appropriate command values ​​via signal circuits to the control valves of the hydraulic circuit 30, lower-level controllers (fuel cell controller, battery controller) (not shown), the inverter / motor 11, the actuator 12, etc. The control panel 14 is provided in the operator's cab and is equipped with a work mode selection switch for selecting a work mode such as a power saving mode, a motor control dial for setting the motor rotation speed, an operation lever, an LCD monitor for displaying the status of the hydraulic excavator, etc. The operation lever is an electric lever that outputs an electrical operation signal (lever signal) according to the amount of operation. When the operator operates the operation lever, the actuator 12 operates according to the operation signal, and as a result, the upper rotating body 52, the boom 53, the arm 54, and the bucket 55 perform various operations desired by the operator.

[0020] The hydrogen supply system shown in FIG. 1 is used as follows. The minimum transportation work of the construction machine 2 (such as loading and unloading from a trailer) is performed using a secondary battery 19 mounted on the construction machine 2 without using the FC 10. Furthermore, when full-scale work is carried out, the connector 7 of the mobile hydrogen station 1 and the connector 9 of the construction machine 2 are connected by a hydrogen supply pipe 8, and the FC 10 is operated using hydrogen supplied from the mobile hydrogen station 1. In this case, it can be said that the mobile hydrogen station 1 reduces the pressure of hydrogen stored in the hydrogen tank (high pressure) 3 to generate reduced-pressure hydrogen, and supplies the reduced-pressure hydrogen to the construction machine 2 via the hydrogen supply pipe 8, and the construction machine 2 is powered by the reduced-pressure hydrogen supplied from the mobile hydrogen station 1. It can also be said that the configuration in Figure 1 is a case where no hydrogen storage tank is provided in the construction machine 2, and reduced-pressure hydrogen supplied from the mobile hydrogen station 1 is supplied directly to the FC 10. In this case, a low-pressure hose can be used as the hydrogen supply pipe 8 to supply hydrogen, which makes it possible to keep the cost of the hydrogen supply pipe 8 lower than that of a high-pressure hose. Also, by not installing a hydrogen tank on the construction machine 2 as shown in Figure 1, there are advantages such as making the construction machine 2 smaller and lighter, and securing space for installing other equipment.

[0021] FIG. 2 is a diagram showing a second example of the hydrogen supply system according to this embodiment. The hydrogen supply system shown in the figure differs from the hydrogen supply system of FIG. 1 in that the mobile hydrogen station 1 is divided into a fuel cell vehicle (FCV) 1A and a hydrogen tank container 1B, but is otherwise similar. The fuel cell vehicle (FCV) 1A is equipped with an FC system (for operating the FCV) 21 and a fuel cell for propelling the mobile hydrogen station 1. In this case, the fuel cell vehicle (FCV) 1A functions as a towing unit that tows the hydrogen tank container 1B. The hydrogen tank container 1B includes a hydrogen tank (high pressure) 3, a hydrogen tank (low pressure) 5, and a connector 7. In this case, the hydrogen tank container 1B functions as a container portion that carries hydrogen. In the hydrogen supply system shown in Figure 2, the mobile hydrogen station 1 is made up of a fuel cell vehicle (FCV) 1A that does not carry hydrogen, and a hydrogen tank container 1B that carries hydrogen, which are separate entities. In this case, when refueling with hydrogen, it is only necessary to change the hydrogen tank container 1B, which is expected to reduce time and simplify the work.

[0022] FIG. 3 is a diagram showing a third example of the hydrogen supply system according to the present embodiment. The hydrogen supply system shown in the figure is similar to the hydrogen supply system in Figure 1 except that there are multiple construction machines 2. That is, the mobile hydrogen station 1 supplies reduced-pressure hydrogen to multiple construction machines 2. Here, the case is shown where three construction machines 2 are connected to one mobile hydrogen station 1 and supplied with reduced-pressure hydrogen. In this case, this configuration can be achieved by providing multiple connectors 7 to the mobile hydrogen station 1 and using multiple hydrogen supply pipes 8. This makes it possible to operate multiple construction machines 2 simultaneously using one mobile hydrogen station 1.

[0023] FIG. 4 is a diagram showing a fourth example of the hydrogen supply system according to the present embodiment. The hydrogen supply system shown in the figure is characterized in that a rotary joint 61 is provided on the upper rotating body 52 of the construction machine 2. The rotary joint 61 is provided on the rotation axis (center of rotation) of the upper rotating body 52 or in a position close to the rotation axis, and is rotatable relative to the upper rotating body 52. ​​The rotary joint 61 is also connected to a connector 9 by a pipe 62. With this configuration, reduced-pressure hydrogen supplied from the mobile hydrogen station 1 is supplied to the construction machine 2 from the connector 9 via the pipe 62 and the rotary joint 61. In construction machines 2 such as hydraulic excavators and crane trucks, work is performed while the upper rotating body 52 on top of the main body rotates. If a connector is mounted on the upper rotating body 52, the hydrogen supply pipe 8 (hose) will be swung around as the upper rotating body 52 rotates, and there is a risk that the upper rotating body 52 and the hydrogen supply pipe 8 will become tangled. Therefore, by mounting a gas rotary joint 61 at or near the center of rotation as shown in Figure 4, the hydrogen supply pipe 8 will not rotate together with the upper rotating body 52 as it rotates, and tangling of the upper rotating body 52 and the hydrogen supply pipe 8 can be prevented.

[0024] FIG. 5 is a diagram showing a fifth example of the hydrogen supply system according to the present embodiment. The illustrated hydrogen supply system is similar to the hydrogen supply system of FIG. 1 except that it adds a tank (hydrogen storage alloy) 23, a tank temperature control unit 24, and a tank temperature control circuit 25 to the construction machine 2. The tank 23 is an example of a storage tank that stores reduced-pressure hydrogen supplied by the mobile hydrogen station 1, and is equipped with a hydrogen storage alloy to store reduced-pressure hydrogen. In this case, reduced-pressure hydrogen supplied from the mobile hydrogen station 1 is supplied to the FC 10 and also to the tank 23. This makes it possible to supply hydrogen from the tank 23 even if, for some reason, the mobile hydrogen station 1 is unable to supply hydrogen. In this case, the tank temperature control unit 24 is controlled by the tank temperature control circuit 25 to adjust the temperature of the tank 23, thereby controlling the pressure of the hydrogen being supplied, etc.

[0025] FIG. 6 is a diagram showing a sixth example of the hydrogen supply system according to the present embodiment. The hydrogen supply system shown in the figure is characterized by the provision of a rotary joint 61 on the undercarriage 51 of the construction machine 2. The rotary joint 61 is provided at the rotation axis (center of rotation) of the upper rotating body 52 or at a position close to the rotation axis, and is rotatable relative to the undercarriage 51. The rotary joint 61 is also connected to a connector 9 by a pipe 62. With this configuration, reduced-pressure hydrogen supplied from the mobile hydrogen station 1 is supplied to the construction machine 2 from the connector 9 via the pipe 62 and the rotary joint 61. In this case, the hydrogen supply pipe 8 will not rotate together with the rotation of the upper rotating body 52, and the upper rotating body 52 and the hydrogen supply pipe 8 can be prevented from becoming entangled.

[0026] Mobile hydrogen stations cannot supply hydrogen anywhere, anytime. For example, supplying vehicles with high-pressure hydrogen of 1 MPa or more is only possible at locations where advance application and safety distances have been met in accordance with the requirements of the High-Pressure Gas Safety Act. Therefore, for vehicles such as construction machinery that move between different work locations depending on the day or that work in small urban environments, it can be difficult to apply in advance and ensure the safety distances mentioned above. On the other hand, if hydrogen is supplied at less than 1 MPa so as not to be subject to the above regulations, the density of hydrogen is low, so the volume of hydrogen required for the construction machine 2 to work for, for example, one day will be very large. As a result, it will be necessary to either install a hydrogen tank that is too large to be mounted on the vehicle body, or to supply hydrogen frequently.

[0027] The hydrogen supply system of this embodiment stores high-pressure hydrogen in a hydrogen tank (high pressure) 5, reduces the pressure to low-pressure hydrogen (reduced pressure hydrogen), and supplies it to the construction machine 2. The construction machine 2 then operates the FC10 using the supplied reduced-pressure hydrogen. In this case, high-pressure hydrogen is not supplied to the construction machine 2, so it is not subject to the above regulations. Furthermore, because high-pressure hydrogen is stored in the hydrogen tank (high pressure) 5, a large amount of hydrogen can be stored without preparing a large tank, and it is possible to store an amount of hydrogen sufficient for the construction machine 2 to work for one day, for example. Therefore, according to the hydrogen supply system of this embodiment, it is possible to provide a hydrogen supply system that enables hydrogen to be supplied to construction machines 2 in various locations and can suppress a decrease in work efficiency due to hydrogen supply work.

[0028] Although the present embodiment has been described above, the technical scope of the present invention is not limited to the scope described in the above embodiment. It is clear from the claims that various modifications and improvements to the above embodiment are also included in the technical scope of the present invention. [Explanation of symbols]

[0029] 1...Mobile hydrogen station, 1A...Fuel cell vehicle (FCV), 1B...Hydrogen tank container, 2...Construction machinery, 3...Hydrogen tank (high pressure), 5...Hydrogen tank (low pressure), 8...Hydrogen supply piping, 10...FC, 19...Secondary battery, 23...Tank, 51...Lower running body, 52...Upper rotating body, 61...Rotary joint

Claims

1. a work machine that uses hydrogen as fuel and is driven by hydrogen; a mobile hydrogen supply device having a hydrogen tank for storing hydrogen under high pressure; a hydrogen supply pipe connecting the work machine and the hydrogen supply device; Equipped with the hydrogen supply device reduces the pressure of hydrogen stored in the hydrogen tank to generate reduced-pressure hydrogen, and supplies the reduced-pressure hydrogen to the work machine via the hydrogen supply pipe; The working machine is driven by the reduced-pressure hydrogen supplied from the hydrogen supply device. Hydrogen supply system.

2. The hydrogen supply system according to claim 1 , wherein the hydrogen supply device supplies the reduced-pressure hydrogen to a plurality of the work machines.

3. the work machine has an upper rotating body and a lower traveling body, a rotary joint is provided on the upper rotating body or the lower traveling body, the hydrogen supply pipe is connected to the rotary joint; 2. The hydrogen supply system according to claim 1, wherein the reduced-pressure hydrogen supplied from the hydrogen supply device is supplied to the work machine via the rotary joint.

4. The work machine is provided with a fuel cell as a power source, 2. The hydrogen supply system according to claim 1, wherein the work machine has a storage tank for storing the reduced-pressure hydrogen supplied by the hydrogen supply device, and the reduced-pressure hydrogen supplied from the hydrogen supply device is supplied to the fuel cell and also to the storage tank.

5. 2. The hydrogen supply system according to claim 1, wherein the hydrogen supply device is divided into a container section that carries hydrogen and a towing section that tows the container section.

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