Hydrogen supply system, fuel cell system, and working machine equipped with the same

Abstract

To provide a fuel cell system for making it possible to reuse surplus hydrogen gas that is not used for power generation in a fuel cell.SOLUTION: A hydrogen supply system (52) for supplying hydrogen gas to a fuel cell (51) for power generation comprises: a plurality of hydrogen tanks (53a, 53b, 53c, 53d, 53e) for storing hydrogen gas; and hydrogen gas supply pipes (55a, 55b, 55c, 55d, 55e) for supplying hydrogen gas from the respective hydrogen tanks (53a, 53b, 53c, 53d, 53e) to the fuel cell (51). At least one of the plurality of hydrogen tanks (53a, 53b, 53c, 53d, 53e) is a first reserve tank (53a) that is connected to a hydrogen gas collecting pipe (56) or a hydrogen gas recovery pipe (58a) and stores hydrogen gas having not been used for power generation in the fuel cell (51).SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a hydrogen supply system for supplying hydrogen gas to a fuel cell, a fuel cell system, and a work machine equipped with the same. [Background technology]

[0002] Conventionally, hydrogen tanks containing hydrogen storage alloys have been widely used in systems that supply hydrogen gas to fuel cells, and are also called MH (metal hydride) tanks (Patent Document 1). Hydrogen storage alloys absorb hydrogen gas by increasing the pressure or cooling it, and release hydrogen gas by decreasing the pressure or heating it. In addition, hydrogen storage alloys can absorb hydrogen gas 1,000 times or more their own volume, so large volumes of hydrogen gas can be stored even in small tanks of less than 1 MPa, as required by the High Pressure Gas Safety Regulations. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 174055 Brochure Summary of the Invention [Problem to be solved by the invention]

[0004] As mentioned above, hydrogen storage alloys need to be heated to extract hydrogen gas from the hydrogen tanks that contain them, but if the amount of hydrogen gas required by the fuel cell fluctuates, the temperature needs to be controlled in accordance with the fluctuations. However, it is difficult to control the amount of heat applied to the hydrogen storage alloy without delay.

[0005] In particular, when a large amount of hydrogen gas is being requested (a state in which a large amount of heat is being provided) and the request for hydrogen gas is stopped, the hydrogen gas pressure inside the hydrogen tank rises rapidly. In order to comply with the High Pressure Gas Safety Regulations, typical hydrogen tanks are equipped with a relief valve that operates at 1.0 MPa or more, and when temperature control cannot keep up, this relief valve is opened and a large amount of surplus hydrogen gas is released into the atmosphere. This results in unnecessary consumption of hydrogen gas. In addition, when surplus hydrogen gas is released into an enclosed space, it is necessary to ventilate the enclosed space vigorously.

[0006] The present invention has been made to solve such problems with the conventional technology, and has an object to provide a hydrogen supply system, a fuel cell system, and a work machine equipped with them, which can reuse surplus hydrogen gas that has been discharged from a hydrogen tank but not used in a fuel cell without releasing it into the atmosphere and without waste. [Means for solving the problem]

[0007] A hydrogen supply system according to a first aspect of the present invention is a hydrogen supply system that supplies hydrogen gas to a fuel cell that generates electricity using hydrogen gas, and comprises a plurality of hydrogen tanks each storing hydrogen gas, and a hydrogen gas supply path that supplies hydrogen gas from each of the hydrogen tanks to the fuel cell, and at least one of the plurality of hydrogen tanks is connected to the hydrogen gas supply path via a hydrogen gas recovery path, and is a reserve tank that stores hydrogen gas that is not used for power generation in the fuel cell.

[0008] The hydrogen supply system further includes a control unit that controls the intake of hydrogen gas that has not been used for power generation into each of the reserve tanks.

[0009] In addition, a first relief valve that opens and closes each of the reserve tanks is disposed in each of the hydrogen gas recovery paths, and the control unit controls each of the first relief valves to open when the pressure of the hydrogen gas in the hydrogen gas supply path is equal to or higher than a predetermined set value, thereby sucking hydrogen gas that has not been used for power generation in the fuel cell into each of the reserve tanks.

[0010] In addition, a second relief valve that releases the hydrogen gas in each reserve tank into the atmosphere is disposed in each of the reserve tanks, and the control unit controls the second relief valve to open and discharge the hydrogen in each of the reserve tanks when the pressure of the hydrogen gas in each of the reserve tanks is equal to or higher than a predetermined set value.

[0011] In addition, when the amount of hydrogen gas stored in a specified reserve tank becomes equal to or greater than a specified amount, the control unit controls the storage of hydrogen gas not used for power generation in the reserve tank to stop suction into the specified reserve tank and to start suction into reserve tanks other than the specified reserve tank.

[0012] In addition, each reserve tank is provided with a hydrogen on-off valve that opens and closes the hydrogen gas supply path, and a hot water on-off valve that opens and closes a hot water path through which hot water flows to heat the reserve tank, and the control unit controls the opening and closing of the hydrogen on-off valve and the hot water on-off valve of each reserve tank.

[0013] The plurality of hydrogen tanks are connected in series or in parallel.

[0014] A hydrogen supply system according to a second aspect of the present invention is a hydrogen supply system that supplies hydrogen gas to a fuel cell that generates electricity using hydrogen gas, and includes a plurality of hydrogen tanks that each store hydrogen gas, and a hydrogen gas supply path that supplies hydrogen gas from each of the hydrogen tanks to the fuel cell, and two of the plurality of hydrogen tanks are first and second reserve tanks that are connected to the hydrogen gas supply path via a hydrogen gas recovery path and store hydrogen gas that is not used for power generation in the fuel cell.

[0015] The hydrogen supply system further includes a control unit that controls the intake of hydrogen gas not used for the power generation into each of the first and second reserve tanks.

[0016] In addition, when storing hydrogen gas not used for power generation in the first and second reserve tanks, the control unit controls the storage of hydrogen gas into the first reserve tank to stop suction into the first reserve tank and start suction into the second reserve tank when the amount of hydrogen gas stored in the first reserve tank becomes equal to or greater than a predetermined amount.

[0017] In addition, the first and second reserve tanks are each provided with a hydrogen on-off valve that opens and closes the hydrogen gas supply path, and a hot water on-off valve that opens and closes a hot water path through which hot water flows for heating the first and second reserve tanks, respectively, and the control unit controls the hydrogen on-off valve and the hot water on-off valve of the first reserve tank to be closed, and the hydrogen on-off valve and the hot water on-off valve of the second reserve tank to be opened.

[0018] In addition, the first and second reserve tanks are each provided with a hydrogen on-off valve that opens and closes the hydrogen gas supply path, and a hot water on-off valve that opens and closes a hot water path through which hot water flows for heating the first and second reserve tanks, respectively, and the control unit controls the hydrogen on-off valve and the hot water on-off valve of the second reserve tank to be closed, and the hydrogen on-off valve and the hot water on-off valve of the first reserve tank to be opened.

[0019] The plurality of hydrogen tanks are connected in series or in parallel.

[0020] A hydrogen supply system according to a third aspect of the present invention is a hydrogen supply system that supplies hydrogen gas to a fuel cell that generates electricity using hydrogen gas, and includes at least one hydrogen tank for storing hydrogen gas, hydrogen gas supply paths that supply hydrogen gas from each of the hydrogen tanks to the fuel cell, and at least one reserve tank that is connected to the hydrogen gas supply path via a hydrogen gas recovery path and stores hydrogen gas not used for power generation in the fuel cell.

[0021] The hydrogen generating system further includes a control unit that controls the intake of hydrogen gas not used for power generation into each of the reserve tanks.

[0022] In addition, a first relief valve that opens and closes each of the reserve tanks is disposed in each of the hydrogen gas recovery paths, and the control unit controls each of the first relief valves to open when the pressure of the hydrogen gas in the hydrogen gas supply path is equal to or higher than a predetermined set value, thereby sucking hydrogen gas that has not been used for power generation in the fuel cell into each of the reserve tanks.

[0023] In addition, a second relief valve that releases the hydrogen gas in each reserve tank into the atmosphere is disposed in each of the reserve tanks, and the control unit controls the second relief valve to open and discharge the hydrogen in each of the reserve tanks when the pressure of the hydrogen gas in each of the reserve tanks is equal to or higher than a predetermined set value.

[0024] In addition, each of the reserve tanks is provided with a hydrogen on-off valve that opens and closes the hydrogen gas supply path, and a hot water on-off valve that opens and closes a hot water path through which hot water for heating the inside of each of the reserve tanks flows, and the control unit controls the hydrogen on-off valve and the hot water on-off valve of any one of all of the reserve tanks to be opened, and controls the hydrogen on-off valves and the hot water on-off valves of all of the other reserve tanks to be closed.

[0025] Moreover, each of the plurality of hydrogen tanks is configured with two or more hydrogen tanks connected in series or in parallel.

[0026] A fuel cell system according to a fourth aspect of the present invention includes the hydrogen supply system according to any one of the first to third aspects.

[0027] A work machine according to a fifth aspect of the present invention includes the fuel cell system according to the fourth aspect. Effect of the Invention

[0028] According to the hydrogen supply system for the fuel cell of the present invention, surplus hydrogen gas that is not used for power generation by the fuel cell after being discharged from the hydrogen tank can be temporarily stored in a reserve tank for recovering surplus hydrogen and reused, which reduces wasteful consumption of hydrogen gas compared to conventional configurations in which the gas is immediately released into the atmosphere. [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 is a schematic side view of an agricultural tractor 1 according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a block diagram showing a schematic configuration of a fuel cell system 22 of FIG. [Diagram 3] 3 is an enlarged vertical cross-sectional view of a hydrogen tank 53c in which the hydrogen storage alloy of FIG. 2 is installed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, similar components are denoted by the same reference numerals and the description thereof will be omitted.

[0031] [First embodiment] 1 to 3 show a hydrogen supply system 52, a fuel cell system 22, and an agricultural tractor (work machine) 1 according to a first embodiment of the present invention. In this embodiment, the vehicle travel direction (forward arrow) is defined as the "forward" of the tractor 1 and each part and system for the tractor, and the left and right directions as seen by an operator riding on the vehicle are defined as the "left and right" of the tractor 1 and each part and system for the tractor. Here, the agricultural tractor 1 is equipped with a fuel cell 51 that generates electricity by an electrochemical reaction between a fuel gas and an oxidizing gas, and is configured to use the electricity generated by this fuel cell 51 as a power source.

[0032] FIG. 1 is a schematic side view of an agricultural tractor 1 according to a first embodiment of the present invention. The tractor 1 in FIG. 1 shows the left side of the entire tractor. The tractor 1, which is a working machine in FIG. 1, is configured to include a vehicle body 2 long in the front-rear direction, a bonnet 3 provided at the front of the vehicle body 2, a cabin 5 mounted at the rear of the vehicle body 2 and accommodating a driver's seat 4 in which an operator sits, a wheeled traveling device 6 that supports the vehicle body 2 so that it can travel, a drive unit 7 that drives the traveling device 6, a three-point link mechanism 9 provided at the rear end of the vehicle body 2, and a PTO shaft (power take-off shaft) 10 that transmits power from the drive unit 7. In this embodiment, an agricultural tractor has been used as the working machine 1, but the present invention is not limited to this, and the working machine 1 can be applied to various working machines, such as agricultural machines such as rice transplanters and combine harvesters, and construction machines such as backhoes, compact track loaders, and skid steer loaders.

[0033] 1 includes a pair of left and right rear wheels 11 and a pair of left and right front wheels 12, with the upper parts of the rear wheels 11 covered with fenders 13. Here, the traveling device 6 is a two-wheel drive / four-wheel switchable four-wheel drive system, and is configured to be switchable between a two-wheel drive state in which only the rear wheels 11 are driven, and a four-wheel drive state in which the rear wheels 11 and the front wheels 12 are driven. Note that the present invention is also applicable to tractors equipped with a two-wheel drive system in which only the rear wheels are driven, or a track-type (crawler-type) traveling device.

[0034] 1 is configured to include an AC drive motor (electric motor) 21 arranged near the rear wheels 11 for driving the wheels or tracks of the traveling device 6, a fuel cell system 22 arranged inside the bonnet 3 for supplying power to the drive motor 21, and a controller 23 arranged inside the bonnet 3 for controlling the supply of power from the fuel cell system 22 to the drive motor 21. Furthermore, a hydrogen gas detector for detecting hydrogen gas may be provided, and in this case, an exhaust door that opens when the hydrogen gas detector detects hydrogen gas to communicate the internal space S1 of the cabin 5 with the outside may be provided in the ceiling wall 43 of the cabin 5.

[0035] Here, the output shaft of the drive motor 21 is indirectly or directly linked to the axle of the rear wheels 11 via a transmission mechanism, and is also switchably linked to the front wheels 12 via a two-wheel drive / four-wheel drive switching mechanism. The fuel cell system 22 generates electricity by reacting hydrogen gas supplied from hydrogen tanks 232A-232C (described later) with air (oxygen) taken in from the outside, and supplies the electricity to the drive motor 21. The controller 23 has an inverter function, converts DC electricity generated by the fuel cell system 22 into AC electricity, and controls the frequency to control the rotation of the drive motor 21. A battery 27 is disposed inside the hood 3 to store surplus electricity of the power supplied from the fuel cell system 22 to the drive motor 21, and the controller 23 may be configured to control the rotation of the drive motor 21 using the electricity stored in the battery 27.

[0036] The three-point link mechanism 9 in Fig. 1 includes a pair of left and right lower links 31 supported on the lower rear end of the vehicle body 2 so as to be vertically rotatable, a pair of left and right lift arms 32 supported on the upper rear end of the vehicle body 2 so as to be vertically rotatable and driven by a hydraulic device, a connecting link 33 connecting the rear ends of the lift arms 32 to the middle parts of the lower links 31 so as to rotate the lower links 31 by rotating the lift arms 32, and a bracket 34 for mounting an upper link. Various working devices are supported so as to be vertically movable by the upper link connected to the rear ends of the pair of left and right lower links 31 and the bracket 34. Input parts of various working devices are connected to the PTO shaft 10 via a drive shaft. The PTO shaft 10 is rotated by power transmitted from a drive motor 21. Here, the working equipment includes tilling equipment, fertilizer spreading equipment, pesticide spreading equipment, harvesting equipment, harvesting equipment, harvesting equipment, spreading equipment, grass, etc., grass collecting equipment, grass forming equipment (roll baler), etc.

[0037] The cabin 5 in Fig. 1 is composed of four cabin frames (pillars) 41 rising from the four corners, transparent walls (not numbered) covering the front, right and rear sides, a transparent boarding door 42 covering the left side, and a ceiling wall 43. Here, a control device 44 including a handle and the like is disposed in front of the cockpit 4, and an air conditioner unit 46 that conditions the interior space S1 of the cabin 5 is disposed below the cockpit 4. In addition, below the cabin 5, boarding steps 8 are disposed on which an operator places his / her feet when getting on and off the cabin 5. Here, the boarding steps 8 are provided below each of the boarding doors 42 on the left and right sides.

[0038] Fig. 2 is a block diagram showing a schematic configuration of the fuel cell system 22 of Fig. 1. The fuel cell system 22 of Fig. 2 is configured to include a fuel cell 51 that generates electric power using hydrogen gas, and a hydrogen supply system 52 that supplies hydrogen gas to the fuel cell 51. The hydrogen supply system 52 of Fig. 2 is configured to include five hydrogen tanks 53a, 53b, 53c, 53d, and 53e that are connected and arranged in parallel and store hydrogen gas, a hydrogen gas supply path 54 that connects the hydrogen tanks 53a, 53b, 53c, 53d, and 53e to the fuel cell 51 so that hydrogen gas can flow and supplies hydrogen gas from each of the hydrogen tanks 53a to 53e to the fuel cell 51, a hot water path 80 that flows hot water for heating each of the hydrogen tanks 53a to 53e, and a control unit 24 that controls the supply of hydrogen gas and the supply of hot water in the fuel cell system 22 and the opening and closing of various valves related thereto. In this embodiment, for convenience, an example in which five hydrogen tanks are arranged has been described, but the present invention is not limited to this, and the vehicle may be configured to have a number of hydrogen tanks other than five. Here, the multiple hydrogen tanks may be connected in series or in parallel.

[0039] The hydrogen gas supply path 54 in Figure 2 is composed of hydrogen gas supply pipes 55a, 55b, 55c, 55d, and 55e connected to the hydrogen inlets and outlets of each of the hydrogen tanks 53a to 53e, and a hydrogen gas collecting pipe 56 that collects all of the hydrogen gas supply pipes 55a, 55b, 55c, 55d, and 55e and connects them to the fuel cell 51.

[0040] In this embodiment, at least one of the multiple hydrogen tanks 53a-53e is connected to hydrogen gas supply path 54 via gas recovery pipes 58a, 58e (hydrogen gas recovery path 58), and is used as a reserve tank for storing hydrogen gas not used for power generation in fuel cell 51. More specifically, of the five hydrogen tanks 53a-53e arranged in parallel, the two hydrogen tanks 53a, 53e on both sides are reserve tanks for recovering surplus hydrogen gas. Here, the two hydrogen tanks 53a, 53e on both sides will be described below as the first reserve tank 53a and the second reserve tank 53e, respectively.

[0041] Referring to FIG. 2, a hydrogen gas supply is connected to first and second reserve tanks 53a and 53e. The supply pipes 55a, 55e are provided with hydrogen on-off valves 57a, 57e for opening and closing the hydrogen gas supply path 54. The first and second reserve tanks 53a, 53e are connected with hydrogen gas recovery pipes 58a, 58e (hydrogen gas recovery paths 58) in parallel with the hydrogen gas supply pipes 55a, 55e. The ends of the hydrogen gas recovery pipes 58a, 58e are connected to a hydrogen gas collection pipe 56, and the hydrogen gas recovery pipes 58a, 58e (hydrogen gas recovery paths 58) are provided with first relief valves 60a, 60e for opening and closing the reserve tanks (first and second reserve tanks 53a, 53e) and flow meters 61a, 61e, respectively. Here, each of the flow meters 61a, 61e measures the flow rate of hydrogen gas recovered from the hydrogen gas collecting pipe 56 through the hydrogen gas recovery pipes 58a, 58e to the first and second reserve tanks 53a, 53e, respectively. Also, the first and second reserve tanks 53a, 53e are provided with second relief valves 62a, 62e, which release the hydrogen gas in each of the reserve tanks (the first and second reserve tanks 53a, 53e) into the atmosphere, respectively.

[0042] 2 includes a hot water tank 70, hot water pipes 71b, 71c, and 71d penetrating the three hydrogen tanks 53b, 53c, and 53d, hot water pipes 71a and 71e penetrating the first and second reserve tanks 53a and 53e, a hot water supply pipe 72 connecting the hot water outlet of the hot water tank 70 to the upstream ends of the hot water pipes 71a, 71b, 71c, 71d, and 71e, and a hot water return pipe 73 connecting the downstream ends of the hot water pipes 71a, 71b, 71c, 71d, and 71e to the hot water return port of the hot water tank 70. The hot water supply pipe 72 is provided with a water pump 74 for circulating hot water through the hot water path 80, a heater 75 for heating the hot water flowing through the hot water path 80, and a thermometer 76 for measuring the temperature of the hot water downstream (outlet side) of the heater 75. Furthermore, hot water on-off valves 78a, 78e are provided at the downstream ends of the hot water pipes 71a, 71e arranged in the first and second reserve tanks 53a, 53e, respectively, to open and close hot water paths 80 through which hot water flows for heating the first and second reserve tanks 53a, 53e.

[0043] 2 controls the first relief valves 60a, 60e to be opened when the pressure of the hydrogen gas in the hydrogen gas supply path 54 is equal to or higher than a predetermined set value, thereby drawing in the hydrogen gas not used for power generation in the fuel cell 51 into each of the reserve tanks (first and second reserve tanks 53a, 53e). The control unit 24 also controls the second relief valves 62a, 62e to be opened when the pressure of the hydrogen gas in each of the reserve tanks (first and second reserve tanks 53a, 53e) is equal to or higher than a predetermined set value, thereby discharging the hydrogen in each of the reserve tanks (first and second reserve tanks 53a, 53e). Furthermore, when the amount of hydrogen gas stored in a predetermined reserve tank becomes equal to or greater than a predetermined amount in storing hydrogen gas not used for power generation in each reserve tank (first and second reserve tanks 53a, 53e), the control unit 24 performs control so as to stop suction into the predetermined reserve tank and start suction into reserve tanks other than the predetermined reserve tank. Here, the predetermined reserve tank may be either one of the first reserve tank 53a or the second reserve tank 53e, or may be both the first reserve tank 53a and the second reserve tank 53e.

[0044] 2 is electrically connected to each of the hydrogen on-off valves 57a, 57e, and controls each of the hydrogen on-off valves 57a, 57e to electrically open and close. That is, the control unit 24 controls the connection between the first reserve tank 53a and the hydrogen gas collecting pipe 56, and the connection between the second reserve tank 53e and the hydrogen gas collecting pipe 56 to open and close at desired times.

[0045] The control unit 24 controls the first relief valves 60a, 60e to open when the hydrogen gas pressure in the hydrogen gas collecting pipe 56 reaches or exceeds a predetermined set value P1, and recovers (stores) excess hydrogen gas from the hydrogen gas collecting pipe 56 into the first reserve tank 53a and the second reserve tank 53e. Note that in this embodiment, the control unit 24 controls the first relief valves 60a, 60e to open when the hydrogen gas pressure in the hydrogen gas collecting pipe 56 reaches or exceeds a predetermined set value P1. When the pressure reaches or exceeds a predetermined set value P1 that is less than 1.0 MPa, the first relief valves 60a, 60e are controlled to open.

[0046] The control unit 24 acquires and accumulates the hydrogen gas flow rate values ​​recovered in the first and second reserve tanks 53a, 53e, respectively, measured by each flow meter 61a, 61e, and controls the first relief valves 60a, 60e of each of the first reserve tanks 53a and the second reserve tank 53e to close when the amount of hydrogen gas in each of the first reserve tanks 53a and the second reserve tanks 53e reaches a predetermined amount V.

[0047] The control unit 24 controls the second relief valves 62a, 62e to open and release the hydrogen gas in the first and second reserve tanks 53a, 53e when the hydrogen gas pressure in the first and second reserve tanks 53a, 53e is equal to or higher than a predetermined set value P2. Here, the set value P2 is greater than the above-mentioned set value P1, and for example, the hydrogen gas pressure in the first and second reserve tanks 53a, 53e is equal to or higher than 1.0 MPa.

[0048] The water pump 74, heater 75, and thermometer 76 are electrically connected to the control unit 24, and the control unit 24 controls the energization of the heater 75 so that the hot water reaches a desired temperature based on temperature data of the hot water downstream (outlet side) of the heater 75 acquired by the thermometer 76. The control unit 24 also controls the water pump 74 so as to achieve a desired hot water flow rate (discharge amount).

[0049] The control unit 24 is electrically connected to each of the hot water on-off valves 78a, 78e, and controls each of the hot water on-off valves 78a, 78e so as to provide a desired hot water flow rate to the hot water pipes 71a, 71e in the first and second reserve tanks 53a, 53e.

[0050] 3 is an enlarged vertical cross-sectional view of hydrogen tank 53c, which is an MH tank containing a hydrogen storage alloy as described above, and has a hydrogen storage alloy layer 82 with an internal space filled with hydrogen gas, and the outer surface of hydrogen storage alloy layer 82 is covered with, for example, a carbon fiber reinforced plastic (CFRP) layer 81. Hydrogen storage alloy layer 82 absorbs hydrogen gas by increasing the pressure or cooling, and releases hydrogen gas by decreasing the pressure or heating. It can absorb hydrogen 1000 times or more its own volume. The other hydrogen tanks 53b, 53d and first and second reserve tanks 53a, 53e in FIG. 2 are similar.

[0051] The operation and effects of the hydrogen supply system 52 configured as above will be described below.

[0052] (a) In this embodiment, in the preparation stage before operation, hydrogen gas is not stored in either the first or second reserve tank 53a, 53e, and during the initial operation, only the first reserve tank 53a is used to recover excess hydrogen gas, and for the second reserve tank 53e, the first relief valve 60e is fixed in a closed state, and the hydrogen on-off valve 57e and the hot water on-off valve 78e are also closed.

[0053] (b) During operation, when hydrogen gas is supplied to the fuel cell 51, the hydrogen on-off valve 57a and the hot water on-off valve 78a of the first reserve tank 53a are closed as described above, and the second reserve tank 53e not only maintains the hydrogen on-off valve 57e and the hot water on-off valve 78e in a closed state, but also fixes the first relief valve 60e of the hydrogen gas recovery pipe 58e in a closed state. Therefore, only hydrogen gas from the three hydrogen tanks 53b, 53c, 53d is supplied to the fuel cell 51 during operation.

[0054] (c) During operation, three hydrogen tanks 53b, 53c, and 53d supply large amounts of hydrogen gas. When the demand for hydrogen gas from the fuel cell 51 is stopped from this state, the hydrogen gas pressure in the hydrogen gas collection pipe 56 rises rapidly. When the hydrogen gas pressure in the hydrogen gas collection pipe 56 eventually reaches or exceeds the set value P1 of the first relief valve 60a, the first relief valve 60a is opened and the surplus hydrogen gas in the hydrogen gas collection pipe 56 is recovered in the first reserve tank 53a via the hydrogen gas recovery pipe 58a.

[0055] (d) The flow rate of excess hydrogen gas recovered in the first reserve tank 53a is measured and integrated by a flow meter 61a, and when the amount of hydrogen gas in the first reserve tank 53a reaches a predetermined amount V, the first relief valve 60a is fixed in a closed state to prevent excess hydrogen gas from entering through the hydrogen gas collecting pipe 56. At the same time, the first relief valve 60e of the second reserve tank 53e, which had been fixed in a closed state, is returned to an operable state, and the second reserve tank 53e is used to recover excess hydrogen gas.

[0056] The effects of this embodiment are summarized as follows.

[0057] (a) The surplus hydrogen gas supplied to the fuel cell 51 is temporarily recovered in the first reserve tank 53a or the second reserve tank 53e for recovering surplus hydrogen gas, and then reused. Therefore, the hydrogen gas is not immediately released into the outside air, and unnecessary consumption of hydrogen gas can be reduced.

[0058] (b) When the hydrogen gas pressure in the first reserve tank 53a for recovering surplus hydrogen gas becomes greater than a predetermined set value P2, the second relief valve 62a is opened to release a portion of the hydrogen gas in the first reserve tank 53a to the outside, thereby maintaining the life of the first reserve tank 53a and reducing the maintenance work. Of course, the same effect can be obtained for the second reserve tank 53e.

[0059] (c) The hot water pipe 71a arranged in the first reserve tank 53a for recovering surplus hydrogen gas is provided with a hot water on-off valve 78a, which prevents the first reserve tank 53a from being heated unnecessarily, thereby saving energy. Of course, the same effect is achieved for the second reserve tank 53e.

[0060] (d) Efficient use of hot water can be achieved by controlling the control unit 24 to close the hot water on-off valve 78a when the hydrogen on-off valve 57a of the first reserve tank 53a is closed, and to open the hot water on-off valve 78a when the hydrogen on-off valve 57a is open. The same applies to the control of the hydrogen on-off valve 57e and the hot water on-off valve 78e of the second reserve tank 53e.

[0061] (e) If two hydrogen tanks, the first reserve tank 53a and the second reserve tank 53e, are provided for recovering surplus hydrogen gas, the amount of surplus hydrogen gas recovered can be increased.

[0062] (f) The control unit 24 automatically alternates between the first reserve tank 53a and the second reserve tank 53e to recover excess hydrogen gas. This allows one tank to be used for normal hydrogen gas supply while the other tank is being used for recovering excess hydrogen gas, thereby enabling efficient use of the first and second reserve tanks 53a, 53e.

[0063] [Variation 1] In this embodiment, at least one of the multiple hydrogen tanks each storing hydrogen gas is described as a reserve tank that stores hydrogen gas that has not been used for power generation in the fuel cell. However, the present invention is not limited to the above-described embodiment, and for example, as a modified example of the above-described embodiment, the system may be configured to include at least one hydrogen tank that stores hydrogen gas, and at least one reserve tank that stores hydrogen gas that has not been used for power generation in the fuel cell. In this embodiment as well, the same operation and effects as those of the present embodiment can be obtained.

[0064] [Variation 2] In this embodiment and the first modified example, in the preparation stage before operation, neither the first nor the second reserve tank 53a, 53e is made to store hydrogen gas, and during the first operation, only the first reserve tank 53a is used to recover excess hydrogen gas, and the second reserve tank 53e is configured to fix the first relief valve 60e in a closed state and close the hydrogen on-off valve 57e and the hot water on-off valve 78e. In contrast, in this modified example, in the preparation stage before operation, only the first reserve tank 53a is left in a state in which hydrogen gas is not stored, and is used to recover excess hydrogen gas, and the second reserve tank 53e is made to store hydrogen gas in the same manner as the other hydrogen tanks 53b, 53c, 53d. This will be described in detail below.

[0065] (a) Before operation, when hydrogen is absorbed (filled) into the hydrogen supply system 52, for example, the hydrogen on-off valve 57a of the first reserve tank 53a is closed and the hydrogen on-off valve 57e of the second reserve tank 53e is opened, and hydrogen gas is drawn in from a hydrogen station or the like through the hydrogen gas collection pipe 56. As a result, hydrogen gas is drawn into and absorbed in the hydrogen tanks 53b, 53c, 53d and the second reserve tank 53e. Meanwhile, hydrogen gas is not drawn into the first reserve tank 53a, whose hydrogen on-off valve 57a is closed, and the tank remains empty. During this hydrogen gas filling, the hot water in the hot water passage is stopped.

[0066] (b) During operation, when hydrogen gas is supplied to the fuel cell 51, the hydrogen on-off valve 57a and the hot water on-off valve 78a of the first reserve tank 53a are closed. In the hot water path, the water pump 74 and the heater 75 are operated to cause hot water heated to a predetermined temperature to flow through the hot water pipes 71b, 71c, 71d, and 71e, thereby heating the three hydrogen tanks 53b, 53c, and 53d and the second reserve tank 53e. As a result, hydrogen gas is supplied to the fuel cell 51 through the hydrogen gas supply pipes 55b, 55c, 55d, and 55e and the hydrogen gas collector pipe 56. At this time, the first reserve tank 53a is not heated, and is connected to the hydrogen gas collector pipe 56 and the other hydrogen gas supply pipes 55b, 55c, 55d, and 55e only through the hydrogen gas recovery pipe 58a having the first relief valve 60a. As described above, hydrogen gas is supplied to the fuel cell 51, and as is well known, the fuel cell 51 causes the hydrogen gas to react with the air (oxygen) taken in from the outside air to generate electricity. The generated electricity is then supplied to the drive motor 21 in FIG. 1 to operate the drive motor 21 and is used not only for propelling the tractor 1 but also for driving various working devices to which power is transmitted from the PTO shaft 10.

[0067] (c) During operation, when the hydrogen demand from the fuel cell 51 is stopped, for example, by stopping farm work, from a state in which the hydrogen tanks 53b, 53c, 53d and the second reserve tank 53e are supplying a large amount of hydrogen gas, the hydrogen gas pressure supplied from the hydrogen tanks 53b, 53c, 53d and the second reserve tank 53e to the hydrogen gas collector pipe 56 rises suddenly. When the hydrogen gas pressure in the hydrogen gas collector pipe 56 eventually exceeds the pressure setting value P1 of the first relief valve 60a of the first reserve tank 53a, the first relief valve 60a is opened, and the excess hydrogen gas in the hydrogen gas collector pipe 56 and the hydrogen gas supply pipes 55b, 55c, 55d, 55e is collected (stored) in the first reserve tank 53a via the hydrogen gas collection pipe 58a. That is, the excess hydrogen gas is collected in the first reserve tank 53a without being released into the atmosphere. At this time, since the first reserve tank 53a is not heated, the surplus hydrogen gas is efficiently stored in the first reserve tank 53a in large quantities.

[0068] (d) When the hydrogen gas in the hydrogen tanks 53b, 53c, 53d and the second reserve tank 53e has been used up, only the first reserve tank 53a is in a hydrogen storage state. Therefore, the next time hydrogen gas is stored (filled) from a hydrogen station or the like, the hydrogen on-off valve 57a of the first reserve tank 53a is opened, while the hydrogen on-off valve 57a of the second reserve tank 53e is closed. 57e is closed, and hydrogen gas is sucked in through the hydrogen gas collector pipe 56 from a hydrogen station or the like. This causes hydrogen gas to be absorbed in the three hydrogen tanks 53b, 53c, and 53d. Also, the first reserve tank 53a has already been in a hydrogen absorption state as described above. Therefore, the second reserve tank 53e is used to collect surplus hydrogen gas the next time the vehicle is operated.

[0069] (e) As described above, by alternately operating a cycle of closing the hydrogen on-off valve 57a and the hot water on-off valve 78a of the first reserve tank 53a and a cycle of closing the hydrogen on-off valve 57e and the hot water on-off valve 78e of the second reserve tank 53e, it is possible to efficiently recover and reuse large amounts of surplus hydrogen gas.

[0070] (f) When the first reserve tank 53a is being used to recover excess hydrogen gas, if the hydrogen gas pressure in the first reserve tank 53a exceeds the set value P2 of the second relief valve 62a, the second relief valve 62a is opened to release a portion of the hydrogen gas in the first reserve tank 53a to the outside, in order to ensure safety.

[0071] (g) Even when the second reserve tank 53e is used to recover excess hydrogen gas, when the hydrogen gas pressure in the second reserve tank 53e reaches or exceeds the set value P2, the second relief valve 62e is opened to release the hydrogen gas in the second reserve tank 53e to the outside in order to ensure safety.

[0072] In this modification, the same effects as those of the present embodiment and modification 1 can be obtained.

[0073] In the present embodiment and the like, for convenience, an example in which three hydrogen tanks are arranged has been described, but the present invention is not limited to this, and may be configured to arrange, for example, one hydrogen tank or a number of hydrogen tanks other than three. Here, the multiple hydrogen tanks may be connected in series or in parallel.

[0074] In addition, in the present embodiment and the like, an example in which two reserve tanks for recovering surplus hydrogen gas are provided has been described, but the present invention is not limited to this, and may be configured to provide a number of reserve tanks other than one or three, for example. Here, the multiple reserve tanks may be connected in series or in parallel.

[0075] In addition, in the present embodiment and the like, the reserve tank used to recover excess hydrogen gas is constructed using a hydrogen storage alloy tank, but the present invention is not limited to this, and the reserve tank may be constructed using a general metal high-pressure hydrogen tank.

[0076] As described above, the hydrogen supply system 52 according to the first aspect of the present invention is a hydrogen supply system 52 that supplies hydrogen gas to a fuel cell 51 that generates electricity using hydrogen gas, and the hydrogen supply system 52 includes a plurality of hydrogen tanks 53a-53e that each store hydrogen gas, and hydrogen gas supply paths 55a-55e, 56 that supply hydrogen gas from each hydrogen tank 53a-53e to the fuel cell 51, and at least one hydrogen tank 53a, 53e of the plurality of hydrogen tanks 53a-53e is connected to the hydrogen gas supply paths 55a-55e, 56 via hydrogen gas recovery paths 58a, 58e, and is a reserve tank that stores hydrogen gas not used for power generation in the fuel cell 51.

[0077] According to the hydrogen supply system 52 of the first embodiment, surplus hydrogen gas that has not been used for power generation in the fuel cell 51 after being discharged from the hydrogen tanks 53b, 53c, 53d can be temporarily stored in reserve tanks 53a, 53e for recovering surplus hydrogen and reused, which reduces wasteful consumption of hydrogen gas compared to the conventional configuration in which the gas is immediately released into the atmosphere.

[0078] In addition to the hydrogen supply system 52 according to the first embodiment, the present invention can further include the following configurations.

[0079] (a) The hydrogen supply system 52 further includes a control unit 24 that controls the intake of hydrogen gas not used for power generation into each of the reserve tanks 53a, 53e.

[0080] (b) In the hydrogen supply system 52, first relief valves 60a, 60e for opening and closing each of the reserve tanks 53a, 53e are disposed in the hydrogen gas recovery paths 58a, 58e, respectively, and the control unit 24 controls the first relief valves 60a, 60e to be opened when the pressure of the hydrogen gas in the hydrogen gas supply paths 55a-55e, 56 is equal to or higher than a predetermined set value, so that hydrogen gas not used for power generation in the fuel cell 51 is sucked into each of the reserve tanks 53a, 53e, respectively.

[0081] (c) In the hydrogen supply system 52, second relief valves 62a, 62e are provided in the reserve tanks 53a, 53e, respectively, to release the hydrogen gas in each of the reserve tanks 53a, 53e into the atmosphere, and the control unit 24 controls the second relief valves 62a, 62e to open respectively, to discharge the hydrogen in the reserve tanks 53a, 53e, respectively, when the pressure of the hydrogen gas in each of the reserve tanks 53a, 53e is equal to or higher than a predetermined set value.

[0082] (d) In addition to any one of configurations (a) to (c), when the amount of hydrogen gas stored in a predetermined reserve tank 53a (53e) of hydrogen gas not used for power generation becomes equal to or greater than a predetermined amount, the control unit 24 controls the storage of hydrogen gas in the reserve tanks 53a, 53e to stop suction into the predetermined reserve tank 53a (53e) and to start suction into the reserve tank 53e (53a) other than the predetermined reserve tank 53a (53e).

[0083] (e) In addition to any one of the configurations (a) to (d), each reserve tank 53a, 53e is provided with a hydrogen on-off valve 57a, 57e that opens and closes the hydrogen gas supply paths 55a to 55e, 56, and a hot water on-off valve 78a, 78e that opens and closes a hot water path 80 through which hot water for heating the reserve tanks 53a, 53e flows, and the control unit 24 controls the opening and closing of the hydrogen on-off valves 57a, 57e and the hot water on-off valves 78a, 78e of each reserve tank 53a, 53e.

[0084] (f) In addition to any one of the configurations (a) to (e), a plurality of hydrogen tanks 53a to 53e are connected in series or in parallel.

[0085] Furthermore, a hydrogen supply system 52 according to a second aspect of the present invention is a hydrogen supply system 52 that supplies hydrogen gas to a fuel cell 51 that generates electricity using hydrogen gas, and the hydrogen supply system 52 includes a plurality of hydrogen tanks 53a-53e that each store hydrogen gas, and hydrogen gas supply paths 55a-55e, 56 that supply hydrogen gas from each hydrogen tank 53a-53e to the fuel cell 51, and two of the plurality of hydrogen tanks 53a-53e, 53a, 53e, are connected to the hydrogen gas supply paths 55a-55e, 56 via hydrogen gas recovery paths 58a, 58e, and serve as first and second reserve tanks that store hydrogen gas not used for power generation in the fuel cell 51.

[0086] According to the hydrogen supply system 52 of the second embodiment, surplus hydrogen gas that has not been used for power generation in the fuel cell after being discharged from the hydrogen tanks 53b to 53d can be temporarily stored in reserve tanks 53a, 53e for recovering surplus hydrogen and reused, which reduces wasteful consumption of hydrogen gas compared to the conventional configuration in which the gas is immediately released into the atmosphere.

[0087] In addition to the hydrogen supply system 52 according to the second embodiment, the present invention can further include the following configurations.

[0088] (g) The hydrogen supply system 52 further includes a control unit 24 that controls the intake of hydrogen gas not used for power generation into each of the first and second reserve tanks 53a, 53e.

[0089] (h) In addition to configuration (g), when storing hydrogen gas not used for power generation in the first and second reserve tanks 53a, 53e, when the amount of hydrogen gas stored in the first reserve tank 53a becomes equal to or greater than a predetermined amount, the control unit 24 controls the storage of hydrogen gas into the first reserve tank 53a to stop suction into the first reserve tank 53a and to start suction into the second reserve tank 53e.

[0090] (i) In addition to configuration (g) or (h), the first and second reserve tanks 53a, 53e are respectively provided with hydrogen on-off valves 57a, 57e which open and close the hydrogen gas supply paths 55a-55e, 56, and hot water on-off valves 78a, 78e which open and close hot water paths 80 which pass hot water for heating the first and second reserve tanks 53a, 53e, respectively, and the control unit 24 controls the hydrogen on-off valves 57a, 57e and the hot water on-off valves 78a, 78e of the first reserve tank 53a to be closed, and the hydrogen on-off valves 57a, 57e and the hot water on-off valves 78a, 78e of the second reserve tank 53e to be opened.

[0091] (j) In addition to any one of the configurations (g) to (i), the first and second reserve tanks 53a, 53e are respectively provided with hydrogen on-off valves 57a, 57e which open and close the hydrogen gas supply paths 55a to 55e, 56, and hot water on-off valves 78a, 78e which open and close hot water paths 80 which pass hot water for heating the first and second reserve tanks 53a, 53e, respectively, and the control unit 24 controls the hydrogen on-off valves 57a, 57e and the hot water on-off valves 78a, 78e of the second reserve tank 53e to be closed, and the hydrogen on-off valves 57a, 57e and the hot water on-off valves 78a, 78e of the first reserve tank 53a to be opened.

[0092] (k) In addition to any one of the configurations (g) to (j), a plurality of hydrogen tanks 53a to 53e are connected in series or in parallel.

[0093] Furthermore, a hydrogen supply system according to a third aspect of the present invention is a hydrogen supply system that supplies hydrogen gas to a fuel cell 51 that generates electricity using hydrogen gas, and the hydrogen supply system includes at least one hydrogen tank for storing hydrogen gas, hydrogen gas supply paths that supply hydrogen gas from each of the hydrogen tanks to the fuel cell, and at least one reserve tank that is connected to the hydrogen gas supply path via a hydrogen gas recovery path and stores hydrogen gas not used for power generation in the fuel cell.

[0094] According to the hydrogen supply system of the third aspect, surplus hydrogen gas that has not been used to generate electricity in the fuel cell after being discharged from the hydrogen tank can be temporarily stored in a reserve tank for recovering surplus hydrogen and reused, which reduces wasteful consumption of hydrogen gas compared to conventional configurations in which the gas is immediately released into the atmosphere.

[0095] In addition to the hydrogen supply system according to the third aspect of the present invention, the following configurations can be added.

[0096] (m) The hydrogen supply system further includes a control unit that controls the intake of hydrogen gas not used in the power generation into each of the reserve tanks.

[0097] (n) In addition to the configuration (m), a first relief valve for opening and closing each of the reserve tanks is provided The control unit is arranged in each of the hydrogen gas recovery paths, and controls each of the first relief valves to open when the pressure of hydrogen gas in the hydrogen gas supply path is equal to or higher than a predetermined set value, thereby sucking hydrogen gas that has not been used for power generation in the fuel cell into each of the reserve tanks.

[0098] (o) In addition to the configuration (m) or (n), a second relief valve that releases the hydrogen gas in each of the reserve tanks into the atmosphere is disposed in each of the reserve tanks, and the control unit controls the second relief valve to open and discharge the hydrogen in each of the reserve tanks when the pressure of the hydrogen gas in each of the reserve tanks is equal to or higher than a predetermined set value.

[0099] (p) In addition to any one of the configurations (m) to (o), each of the reserve tanks is provided with a hydrogen on-off valve for opening and closing the hydrogen gas supply path, and a hot water on-off valve for opening and closing a hot water path through which hot water for heating the inside of each of the reserve tanks flows, and the control unit controls the hydrogen on-off valve and the hot water on-off valve of any one of all of the reserve tanks to be opened, and controls the hydrogen on-off valve and the hot water on-off valve of all of the other reserve tanks to be closed.

[0100] (q) In addition to any one of the configurations (m) to (p), the plurality of hydrogen tanks are each configured by connecting two or more hydrogen tanks in series or in parallel.

[0101] The present invention further provides a fuel cell system including any one of the hydrogen supply systems described above, and a working machine including the fuel cell system.

[0102] Although the present invention has been described above, the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0103] 1. Tractor (an example of a work machine) 22 Fuel Cell System 23 Control Unit 51 Fuel Cell 52 Hydrogen Supply System 53a, 53e 1st and 2nd reserve tanks (hydrogen tanks) 53b, 53c, 53d Hydrogen tank 55a, 55b, 55c, 55d, 55e Hydrogen gas supply pipe (part of the hydrogen gas supply path) 56 Hydrogen gas collector pipe (part of the hydrogen gas supply route) 57a, 57e Hydrogen on-off valve 58a, 58e Hydrogen gas recovery pipe (hydrogen gas recovery path) 60a, 60e First relief valve 61a, 61e flowmeter 62a, 62e Second relief valve 71a, 71b, 71c, 71d, 71e Hot water pipe (part of hot water route) 78a, 78e Hot water on-off valve

Claims

1. 1. A hydrogen supply system for supplying hydrogen gas to a fuel cell that uses hydrogen gas to generate electricity, comprising: A plurality of hydrogen tanks each storing hydrogen gas; a hydrogen gas supply path for supplying hydrogen gas from each of the hydrogen tanks to the fuel cell; A hydrogen supply system, wherein at least one of the plurality of hydrogen tanks is a reserve tank that is connected to the hydrogen gas supply path via a hydrogen gas recovery path and stores hydrogen gas that is not used for power generation in the fuel cell.

2. 2. The hydrogen supply system according to claim 1, further comprising a control unit that controls the intake of hydrogen gas not used for said power generation into each of said reserve tanks.

3. a first relief valve for opening and closing each of the reserve tanks is disposed in each of the hydrogen gas recovery paths; the control unit controls the first relief valves to be opened when the pressure of the hydrogen gas in the hydrogen gas supply path is equal to or higher than a predetermined set value, so that the hydrogen gas not used for power generation in the fuel cell is sucked into each of the reserve tanks. The hydrogen supply system according to claim 2 .

4. a second relief valve for releasing hydrogen gas in each of the reserve tanks into the atmosphere is provided in each of the reserve tanks; the control unit controls the second relief valves to open when the pressure of the hydrogen gas in each of the reserve tanks is equal to or higher than a predetermined set value, thereby discharging the hydrogen in each of the reserve tanks. The hydrogen supply system according to claim 2 or 3.

5. the control unit controls, when an amount of hydrogen gas stored in a predetermined reserve tank becomes equal to or greater than a predetermined amount, the control unit stops suction into the predetermined reserve tank and starts suction into reserve tanks other than the predetermined reserve tank, in storing hydrogen gas not used for power generation in the reserve tanks. The hydrogen supply system according to any one of claims 2 to 4.

6. Each of the reserve tanks includes: a hydrogen on-off valve that opens and closes the hydrogen gas supply path; a hot water on-off valve for opening and closing a hot water passage through which hot water for heating the inside of the reserve tank flows; are arranged respectively, The control unit controls opening and closing of the hydrogen on-off valve and the hot water on-off valve of each of the reserve tanks. The hydrogen supply system according to any one of claims 2 to 5.

7. The plurality of hydrogen tanks are connected in series or in parallel. The hydrogen supply system according to any one of claims 1 to 6.

8. 1. A hydrogen supply system for supplying hydrogen gas to a fuel cell that uses hydrogen gas to generate electricity, comprising: A plurality of hydrogen tanks each storing hydrogen gas; a hydrogen gas supply path for supplying hydrogen gas from each of the hydrogen tanks to the fuel cell; Two of the plurality of hydrogen tanks are connected to the hydrogen gas supply path. a hydrogen supply system including first and second reserve tanks connected via a recovery path for storing hydrogen gas not used for power generation in the fuel cell;

9. 9. The hydrogen supply system according to claim 8, further comprising a control unit that controls the intake of the hydrogen gas not used for the power generation into each of the first and second reserve tanks.

10. the control unit controls, in storing the hydrogen gas not used for the power generation in the first and second reserve tanks, to stop suction into the first reserve tank and start suction into the second reserve tank when an amount of hydrogen gas stored in the first reserve tank becomes equal to or greater than a predetermined amount. The hydrogen supply system according to claim 9.

11. The first and second reserve tanks include: a hydrogen on-off valve that opens and closes the hydrogen gas supply path; a hot water on-off valve for opening and closing a hot water passage through which hot water for heating the first and second reserve tanks flows; are arranged respectively, the control unit controls the hydrogen on-off valve and the hot water on-off valve of the first reserve tank to be closed, and the hydrogen on-off valve and the hot water on-off valve of the second reserve tank to be opened. The hydrogen supply system according to claim 9 or 10.

12. The first and second reserve tanks include: a hydrogen on-off valve that opens and closes the hydrogen gas supply path; a hot water on-off valve for opening and closing a hot water passage through which hot water for heating the first and second reserve tanks flows; are arranged respectively, the control unit controls the hydrogen on-off valve and the hot water on-off valve of the second reserve tank to be closed, and the hydrogen on-off valve and the hot water on-off valve of the first reserve tank to be opened. The hydrogen supply system according to any one of claims 9 to 11.

13. The plurality of hydrogen tanks are connected in series or in parallel. The hydrogen supply system according to any one of claims 8 to 12.

14. 1. A hydrogen supply system for supplying hydrogen gas to a fuel cell that uses hydrogen gas to generate electricity, comprising: at least one hydrogen tank for storing hydrogen gas; a hydrogen gas supply path for supplying hydrogen gas from each of the hydrogen tanks to a fuel cell; at least one reserve tank connected to the hydrogen gas supply path via a hydrogen gas recovery path, the reserve tank storing hydrogen gas not used for power generation in the fuel cell; A hydrogen supply system equipped with:

15. 15. The hydrogen supply system according to claim 14, further comprising a control unit that controls the intake of the hydrogen gas not used for the power generation into each of the reserve tanks.

16. a first relief valve for opening and closing each of the reserve tanks is disposed in each of the hydrogen gas recovery paths; The control unit is configured to: controlling the first relief valves to be opened so that hydrogen gas not used for power generation in the fuel cell is drawn into each of the reserve tanks; The hydrogen supply system according to claim 15.

17. a second relief valve for releasing hydrogen gas in each of the reserve tanks into the atmosphere is provided in each of the reserve tanks; the control unit controls the second relief valves to open when the pressure of the hydrogen gas in each of the reserve tanks is equal to or higher than a predetermined set value, thereby discharging the hydrogen in each of the reserve tanks.

17. The hydrogen supply system according to claim 15 or 16.

18. Each of the reserve tanks includes: a hydrogen on-off valve that opens and closes the hydrogen gas supply path; a hot water on-off valve for opening and closing a hot water passage through which hot water for heating each of the reserve tanks flows; are arranged respectively, The hydrogen supply system according to any one of claims 15 to 17, wherein the control unit controls the hydrogen on-off valve and the hot water on-off valve of any one of all the reserve tanks to be opened, and controls the hydrogen on-off valves and the hot water on-off valves of all the other reserve tanks to be closed.

19. The plurality of hydrogen tanks are each configured by connecting two or more hydrogen tanks in series or in parallel. The hydrogen supply system according to any one of claims 14 to 18.

20. A fuel cell system comprising the hydrogen supply system according to any one of claims 1 to 19.

21. A work machine comprising the fuel cell system according to claim 20.

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