Hydrogen supply system

Abstract

Provided is a hydrogen supply system (1) that is equipped with a plurality of hydrogen storage alloy tanks (11, 12, 13, 14) for storing a hydrogen storage alloy and supplies hydrogen to a hydrogen supply destination (20), the hydrogen supply system (1) being characterized in that prior to supplying hydrogen to the hydrogen supply destination (20), a heat medium is supplied to some of the hydrogen storage alloy tanks among the plurality of hydrogen storage alloy tanks (11, 12, 13, 14) and preheated, and hydrogen is moved between the hydrogen storage alloy tanks to which the heat medium is supplied and a hydrogen storage alloy tank (11) to which the heat medium is not supplied.

Description

Hydrogen Supply System

[0001] The present invention relates to a hydrogen supply system.

[0002] In recent years, a method using a hydrogen storage alloy tank containing a hydrogen storage alloy has attracted attention as a method for safely storing and supplying large amounts of hydrogen. In this method, hydrogen is stored in the hydrogen storage alloy tank by absorbing hydrogen into the alloy, and hydrogen is then released from the hydrogen storage alloy, and the hydrogen is supplied from the hydrogen storage alloy tank to a hydrogen supply destination such as a fuel cell.

[0003] The hydrogen storage alloy is an exothermic reaction when it absorbs hydrogen, and an endothermic reaction when it releases hydrogen. Therefore, to promote these reactions, it is necessary to heat or cool the hydrogen storage alloy in the hydrogen storage alloy tank.

[0004] Patent Document 1 discloses an operating method using a circulation device that circulates a heat medium such as water as a method for heating and cooling a hydrogen storage alloy tank.

[0005] Furthermore, when starting the supply of hydrogen from a hydrogen storage alloy tank to a hydrogen supply destination, if the temperature of the hydrogen storage alloy tank is low, a sufficient amount of hydrogen may not be released from the hydrogen storage alloy, making it impossible to supply high-pressure hydrogen to the hydrogen supply destination. For this reason, as disclosed in Patent Document 1, a method is known in which the hydrogen storage alloy tank is preheated to increase the pressure inside the hydrogen storage alloy tank before starting the supply of hydrogen to the hydrogen supply destination. This method allows high-pressure hydrogen to be supplied from the hydrogen storage alloy tank to the hydrogen supply destination even at the start of the hydrogen supply.

[0006] On the other hand, when preheating a hydrogen storage alloy tank, the internal pressure of the hydrogen storage alloy tank may rise excessively. In particular, when the hydrogen storage alloy tank has a large amount of stored hydrogen, the internal pressure of the hydrogen storage alloy tank is likely to increase due to preheating, and it may be difficult to precisely adjust the internal pressure by adjusting the preheating temperature, etc.

[0007] Therefore, in order to ensure safety and in accordance with legal regulations, a method can be considered in which a safety valve is provided that activates when the internal pressure of the hydrogen storage alloy tank exceeds a predetermined value, and by activating the safety valve, the hydrogen inside the hydrogen storage alloy tank is released to the outside, thereby reducing the internal pressure of the hydrogen storage alloy tank.

[0008] Japanese Patent Application Laid-Open No. 2022-106596

[0009] Generally, when a hydrogen storage alloy tank is preheated, the internal pressure of the tank rises excessively, and the hydrogen released to the outside by the activation of the safety valve is not supplied to the hydrogen supply destination. In other words, it is difficult to reuse the hydrogen released to the outside. Therefore, the method of controlling the internal pressure of the hydrogen storage alloy tank during preheating by activating the safety valve has the problem of reducing the total flow rate of hydrogen that can be supplied to the hydrogen supply destination.

[0010] An object of the present invention is to provide a hydrogen supply system that preheats a hydrogen storage alloy tank before starting to supply hydrogen from the hydrogen storage alloy tank to a hydrogen supply destination, and that suppresses a decrease in the total flow rate of hydrogen that can be supplied to the hydrogen supply destination. That is, an object of the present invention is to provide a hydrogen supply system that can supply high-pressure hydrogen at the start of hydrogen supply while suppressing a decrease in the total flow rate of hydrogen that can be supplied to the hydrogen supply destination.

[0011] One aspect of the present invention is a hydrogen supply system that comprises a plurality of hydrogen storage alloy tanks that contain hydrogen storage alloys, heat medium piping connected to each hydrogen storage alloy tank and through which a heat medium flows, and hydrogen piping connecting the plurality of hydrogen storage alloy tanks to each other and through which hydrogen released from the hydrogen storage alloy tanks flows, and is a hydrogen supply system that supplies hydrogen to a hydrogen destination, and is characterized in that before supplying hydrogen to the hydrogen destination, a heat medium is supplied to some of the plurality of hydrogen storage alloy tanks to preheat them, and hydrogen is transferred between the hydrogen storage alloy tanks to which the heat medium is supplied and the hydrogen storage alloy tanks to which the heat medium is not supplied.

[0012] According to the hydrogen supply system of one aspect of the present invention, when hydrogen supply starts, it is possible to supply high-pressure hydrogen while suppressing a decrease in the total flow rate of hydrogen that can be supplied to the hydrogen supply destination.

[0013] It is a schematic diagram of a hydrogen supply system according to an embodiment. It is a block diagram showing the configuration of a hydrogen supply system according to an embodiment. It is a flowchart showing the operation of a hydrogen supply system according to an embodiment, which shows the processing procedure of a control device.

[0014] Hereinafter, an example of an embodiment of a hydrogen supply system according to the present invention will be described in detail with reference to the drawings. The embodiment described below is merely an example, and the present invention is not limited to the following embodiment. Furthermore, the present invention also includes configurations that are formed by selectively combining multiple embodiments described below.

[0015] The system of the present invention includes a computer. The computer executes a program to realize the functions of the system. The computer's main hardware configuration is a processor that operates according to the program. The processor may be of any type, as long as it can realize the above functions by executing the program. The processor is composed of one or more electronic circuits, including an integrated circuit (IC) or a large-scale integrated circuit (LSI). The electronic circuits may be integrated into a single chip or may be provided on multiple chips. The chips may be integrated into a single device or may be provided on multiple devices. The program is stored in a non-transitory storage medium, such as a computer-readable ROM, optical disk, or hard disk drive. The program may be pre-stored in the storage medium or may be supplied to the storage medium via a wide-area communication network, including the Internet.

[0016] 1 is a schematic diagram of a hydrogen supply system 1 according to this embodiment. The hydrogen supply system 1 comprises a hydrogen storage device 10 including a plurality of hydrogen storage alloy tanks, a fuel cell 20 as a hydrogen supply destination, and a control device 30 that controls the entire hydrogen supply system 1. The hydrogen supply system 1 supplies hydrogen stored in the hydrogen storage device 10 to the fuel cell 20 in response to a hydrogen supply request from the fuel cell 20 and a predetermined hydrogen output plan.

[0017] In this embodiment, the hydrogen storage device 10 includes four hydrogen storage alloy tanks 11, 12, 13, and 14. The number of hydrogen storage alloy tanks may be two or more, and may be two to three, or five or more.

[0018] As will be described in more detail later, the hydrogen supply system 1 has a mechanism for preheating the hydrogen storage alloy tanks before starting the supply of hydrogen from the hydrogen storage device 10 to the fuel cell 20. At this time, only some of the hydrogen storage alloy tanks are preheated. In this embodiment, the case where the hydrogen storage alloy tank 11 is not preheated, and only the hydrogen storage alloy tanks 12, 13, and 14 are preheated will be described.

[0019] The hydrogen storage device 10 is connected to a hydrogen production device (not shown) and is configured to store hydrogen produced by the hydrogen production device. An example of a hydrogen production device is a device that produces hydrogen by solid polymer water decomposition. The supply of hydrogen from the hydrogen production device to the hydrogen storage device 10 may be controlled by, for example, a control device 30.

[0020] The hydrogen storage alloy tanks 11, 12, 13, and 14 contain a hydrogen storage alloy. Here, the hydrogen storage alloy refers to a metallic material that can store hydrogen between its crystal lattices and that reversibly stores and releases hydrogen in response to temperature changes. The composition of the hydrogen storage alloy is not particularly limited, and a titanium-iron alloy, for example, is used.

[0021] The hydrogen storage alloy tanks 11, 12, 13, and 14 have, for example, a cylindrical shape and are substantially the same as one another. The hydrogen storage alloy tanks 11, 12, 13, and 14 are fixed to, for example, a shelf-like support provided in the building in which the hydrogen storage device 10 is installed.

[0022] The arrangement of the hydrogen storage alloy tanks 11, 12, 13, and 14 is not particularly limited. For example, the hydrogen storage alloy tanks 11, 12, 13, and 14 may be placed on their sides and stacked vertically. In this case, the hydrogen storage alloy tank 11, which is not preheated, may be placed above the hydrogen storage alloy tanks 12, 13, and 14, which are preheated. Because the hydrogen storage alloy tank 11 is not preheated, there is no need to supply a heat medium, as described below, before starting the supply of hydrogen from the hydrogen storage device 10 to the fuel cell 20. Therefore, by placing the hydrogen storage alloy tank 11 above the hydrogen storage alloy tanks 12, 13, and 14, energy to push the heat medium upward is not required, which is efficient.

[0023] The hydrogen storage alloy tanks 11, 12, 13, and 14 are each provided with a pressure gauge 15 (see FIG. 2) that measures the internal pressure of the hydrogen storage alloy tanks 11, 12, 13, and 14. The internal pressure values ​​measured by the pressure gauge 15 are transmitted to the control device 30 via wired or wireless communication.

[0024] The fuel cell 20 is a device that generates electricity using hydrogen. For example, a polymer electrolyte fuel cell is used as the fuel cell 20. Note that, although the fuel cell 20 is used as an example of a hydrogen supply destination of the hydrogen storage device 10 in this embodiment, the hydrogen supply destination of the hydrogen storage device 10 is not limited to this.

[0025] 1, the hydrogen supply system 1 further includes heat medium piping 40 connected to each of the hydrogen storage alloy tanks 11, 12, 13, and 14. The heat medium piping 40 is connected to a circulation device 50, and a heat medium flows through the heat medium piping 40. For example, water can be used as the heat medium. The configuration of the circulation device 50 is not particularly limited as long as it can circulate the heat medium through the heat medium piping 40 and can exchange heat with the heat medium.

[0026] When hydrogen is absorbed into a hydrogen storage alloy, an exothermic reaction occurs, and when hydrogen is released from the hydrogen storage alloy, an endothermic reaction occurs. Therefore, when hydrogen is released from the hydrogen storage alloy, hot water is circulated as a heat medium to heat the hydrogen storage alloy.

[0027] The heat medium piping 40 includes a heat medium piping 41 for allowing the heat medium flowing out from the circulation device 50 to flow into the hydrogen storage device 10, and a heat medium piping 42 for allowing the heat medium flowing out from the hydrogen storage device 10 to flow into the circulation device 50.

[0028] The heat medium piping 41 includes a main piping 43 and branch piping 43A, 43B, 43C, and 43D branching from the main piping 43. The branch piping 43A is connected to the hydrogen storage alloy tank 11, the branch piping 43B is connected to the hydrogen storage alloy tank 12, the branch piping 43C is connected to the hydrogen storage alloy tank 13, and the branch piping 43D is connected to the hydrogen storage alloy tank 14. In other words, the heat medium supplied from the circulation device 50 is supplied directly to each hydrogen storage alloy tank without passing through other hydrogen storage alloy tanks. Note that the configuration of the heat medium piping 41 is not limited to this, as long as it can circulate the heat medium flowing out of the circulation device 50 to each of the hydrogen storage alloy tanks 11, 12, 13, and 14.

[0029] Similarly, the heat medium piping 42 includes a main piping 44 and branch piping 44A, 44B, 44C, and 44D branching off from the main piping 44. The branch piping 44A is connected to the hydrogen storage alloy tank 11, the branch piping 44B is connected to the hydrogen storage alloy tank 12, the branch piping 44C is connected to the hydrogen storage alloy tank 13, and the branch piping 44D is connected to the hydrogen storage alloy tank 14. The configuration of the heat medium piping 42 is not limited to this, as long as it can circulate the heat medium flowing out of the hydrogen storage alloy tanks 11, 12, 13, and 14 to the circulation device 50.

[0030] The branch pipes 43A, 43B, 43C, and 43D are provided with valves 45A, 45B, 45C, and 45D that can open and close the branch pipes 43A, 43B, 43C, and 43D, respectively. As will be described in detail later, the opening and closing of the valves 45A, 45B, 45C, and 45D can be controlled by the control device 30.

[0031] 1, the hydrogen supply system 1 further includes a hydrogen pipe 60 through which hydrogen released from the hydrogen storage alloy tanks flows. The hydrogen pipe 60 is arranged to connect the hydrogen storage alloy tanks 11, 12, 13, and 14 to each other.

[0032] Specifically, the hydrogen piping 60 includes a hydrogen piping 60A connected to the hydrogen storage alloy tank 11, a hydrogen piping 60B connected to the hydrogen storage alloy tank 12, a hydrogen piping 60C connected to the hydrogen storage alloy tank 13, and a hydrogen piping 60D connected to the hydrogen storage alloy tank 14. The hydrogen piping 60 further includes a hydrogen piping 60E where hydrogen circulating through the hydrogen piping 60A, 60B, 60C, and 60D join together. The hydrogen piping 60E is connected to the fuel cell 20. The configuration of the hydrogen piping 60 is not limited to this, as long as it can connect the hydrogen storage alloy tanks 11, 12, 13, and 14 to each other and supply hydrogen to the fuel cell 20.

[0033] Hydrogen pipes 60A, 60B, 60C, and 60D are provided with valves 61A, 61B, 61C, and 61D that can open and close hydrogen pipes 60A, 60B, 60C, and 60D, respectively. Hydrogen pipe 60E is also provided with valve 61E that can open and close hydrogen pipe 60E. As will be described in detail later, the opening and closing of valves 61A, 61B, 61C, 61D, and 61E can be controlled by control device 30.

[0034] The hydrogen supply system 1 further includes a safety valve (not shown) that operates when the internal pressure of the hydrogen storage alloy tanks 11, 12, 13, and 14 exceeds a predetermined value, thereby reducing the internal pressure of the hydrogen storage alloy tanks 11, 12, 13, and 14. The safety valve may be provided in each of the hydrogen storage alloy tanks 11, 12, 13, and 14, or may be provided in the hydrogen piping 60. The pressure at which the safety valve operates is, for example, 1 MPaG or less.

[0035] The control device 30 performs overall control of the hydrogen supply system 1, including controlling the opening and closing of valves 45A, 45B, 45C, and 45D provided in the heat medium pipe 40 and valves 61A, 61B, 61C, 61D, and 61E provided in the hydrogen pipe 60. The control device 30 has a memory that stores various setting information, control programs, etc., and a processor that realizes functions by reading and executing the control programs.

[0036] The control device 30 may be provided in the building in which the hydrogen storage device 10 is installed, or may be provided remotely.

[0037] Next, the configuration of the control device 30 and the processing procedure of the hydrogen supply system 1 will be described with reference to Figures 2 and 3. Figure 2 is a block diagram showing the configuration of the hydrogen supply system 1, and Figure 3 is a flowchart showing the operation of the hydrogen supply system 1, illustrating the processing procedure of the control device 30.

[0038] 2 , the control device 30 is connected to pressure gauges 15 provided in the hydrogen storage alloy tanks 11, 12, 13, and 14, respectively, and acquires information about the internal pressures of the hydrogen storage alloy tanks 11, 12, 13, and 14 from the pressure gauges 15. The control device 30 is also configured to send control signals to valves 45A, 45B, 45C, and 45D provided in the heat medium piping 40 and valves 61A, 61B, 61C, 61D, and 61E provided in the hydrogen piping 60. The control device 30 is also connected to the circulation device 50 and configured to send control signals to the circulation device 50.

[0039] The control device 30 is connected to the fuel cell 20 and receives information related to the supply of hydrogen from the fuel cell 20. A predetermined hydrogen output plan and the like may also be stored in the control device 30. The control device 30 controls the opening and closing of valves 45A, 45B, 45C, and 45D provided in the heat medium piping 40 and valves 61A, 61B, 61C, 61D, and 61E provided in the hydrogen piping 60 in accordance with the hydrogen supply request received from the fuel cell 20 and the predetermined hydrogen output plan.

[0040] Next, a description will be given of the processing procedure of the control device 30 in the hydrogen supply system 1. In the following, a case where only the hydrogen storage alloy tanks 12, 13, and 14 in the hydrogen storage device 10 are preheated will be described.

[0041] As shown in Figure 3, when preheating of the hydrogen storage device 10 is required due to a request for hydrogen supply from the fuel cell 20 or a predetermined hydrogen output plan (step S1: Yes), the control device 30 circulates hot water through the heat transfer medium piping 40 and begins preheating of the hydrogen storage device 10 (step S2).

[0042] During preheating, the control device 30 opens only the valves 45B, 45C, and 45D (step S3), but does not open the valve 45A. In other words, hot water flows through the branch pipes 43B, 43C, and 43D, and the hydrogen storage alloy tanks 12, 13, and 14 are preheated, but hot water does not flow through the branch pipe 43A, and the hydrogen storage alloy tank 11 is not preheated.

[0043] A hydrogen storage alloy has the property that the equilibrium pressure during the hydrogen release process (hereinafter referred to as the release pressure) and the equilibrium pressure during the hydrogen absorption process (hereinafter referred to as the absorption pressure) increase as the temperature rises. Therefore, by preheating the hydrogen storage alloy tanks 12, 13, and 14, the internal pressure of the hydrogen storage alloy tanks 12, 13, and 14 increases. This makes it possible to supply a large flow rate and high pressure of hydrogen to the fuel cell 20 even in the early stages of starting the supply of hydrogen from the hydrogen storage device 10 to the fuel cell 20.

[0044] On the other hand, since the hydrogen storage alloy tank 11 is not preheated, there is almost no increase in the internal pressure of the hydrogen storage alloy tank 11. Therefore, the internal pressure of the hydrogen storage alloy tank 11 is smaller than the internal pressures of the hydrogen storage alloy tanks 12, 13, and 14.

[0045] Next, the control device 30 acquires the internal pressure of the hydrogen storage alloy tanks 12, 13, and 14 (step S4) and determines whether the internal pressure is equal to or greater than a predetermined reference value (step S5). The reference value is preferably smaller than the internal pressure value that activates the safety valve. The reference value is, for example, equal to or greater than 0.8 MPaG and equal to or less than 0.95 MPaG.

[0046] If the internal pressure value is equal to or greater than the predetermined reference value (step S5: Yes), the control device 30 opens the valves 61B, 61C, and 61D provided on the hydrogen pipes 60B, 60C, and 60D, and the valve 61A provided on the hydrogen pipe 60A (step S6). At this time, among the valves 61B, 61C, and 61D, only the valves 61B, 61C, and 61D provided on the hydrogen pipes 60B, 60C, and 60D connected to the hydrogen storage alloy tanks 12, 13, and 14 whose internal pressure value is equal to or greater than the reference value may be opened. For example, if the internal pressure of only the hydrogen storage alloy tank 12 among the hydrogen storage alloy tanks 12, 13, and 14 is equal to or greater than the reference value, only the valve 61B of the valves 61B, 61C, and 61D may be opened. On the other hand, if the internal pressure value is less than the predetermined reference value (step S5: No), the process returns to step S4.

[0047] As described above, the internal pressure of the hydrogen storage alloy tank 11 is smaller than the internal pressure of the hydrogen storage alloy tanks 12, 13, and 14. Therefore, by opening the valves 61A, 61B, 61C, and 61D, hydrogen inside the hydrogen storage alloy tanks 12, 13, and 14 that are being preheated moves to the hydrogen storage alloy tank 11 that is not being preheated. In other words, hydrogen moves between the hydrogen storage alloy tanks 12, 13, and 14 that are supplied with a heat medium and the hydrogen storage alloy tank 11 that is not supplied with a heat medium.

[0048] Hydrogen storage alloys have a property that their release pressure is smaller than their storage pressure under the same temperature conditions. When hydrogen is transferred between the hydrogen storage alloy tanks 12, 13, and 14 and the hydrogen storage alloy tank 11, hydrogen is released from the hydrogen storage alloy tanks 12, 13, and 14, and the internal pressure of the hydrogen storage alloy tanks 12, 13, and 14 changes from the storage pressure to the release pressure. In other words, it is possible to reduce the internal pressure of the hydrogen storage alloy tanks 12, 13, and 14 without activating the safety valve.

[0049] Furthermore, the hydrogen released from the hydrogen storage alloy tanks 12, 13, and 14 is not released to the outside, but is instead absorbed in the hydrogen storage alloy contained in the hydrogen storage alloy tank 11. As described above, the hydrogen storage alloy tank 11 is connected to the fuel cell 20 via the hydrogen piping 60. Therefore, the hydrogen absorbed in the hydrogen storage alloy contained in the hydrogen storage alloy tank 11 can be supplied to the fuel cell 20 by separately heating the hydrogen storage alloy tank 11. Therefore, the total flow rate of hydrogen that can be supplied to the fuel cell 20 does not decrease. As a result, it is possible to supply hydrogen to the fuel cell 20 for a long period of time.

[0050] In addition, as described above, the absorption of hydrogen into a hydrogen storage alloy is an exothermic reaction. Therefore, when hydrogen released from the hydrogen storage alloy tanks 12, 13, and 14 is absorbed into the hydrogen storage alloy contained in the hydrogen storage alloy tank 11, the temperature of the hydrogen storage alloy tank 11 rises. In other words, the hydrogen storage alloy tank 11 achieves the same effect as preheating even though no heat transfer medium is supplied. In other words, the configuration of the present invention allows the hydrogen storage alloy tank 11 to be preheated while reducing the energy consumed to supply a heat transfer medium to the hydrogen storage alloy tank 11.

[0051] In addition, from the viewpoint of efficiently storing the hydrogen released from the hydrogen storage alloy tanks 12, 13, and 14 in the hydrogen storage alloy contained in the hydrogen storage alloy tank 11, it is preferable that the hydrogen storage capacity of the hydrogen storage alloy tank 11 be smaller than the hydrogen storage capacity of the hydrogen storage alloy tanks 12, 13, and 14 before hydrogen is transferred between the hydrogen storage alloy tanks.

[0052] When the control device 30 receives a request for hydrogen supply from the fuel cell 20 or when hydrogen supply from the hydrogen storage device 10 to the fuel cell 20 is required due to a predetermined hydrogen output plan (step S7: Yes), it opens the valve 61E provided on the hydrogen piping 60E to start the supply of hydrogen to the fuel cell 20 (step S8). After starting the supply of hydrogen to the fuel cell 20, the control device 30 also appropriately opens the valve 61A provided on the hydrogen piping 60A connected to the hydrogen storage alloy tank 11. This allows hydrogen released from all of the hydrogen storage alloy tanks 11, 12, 13, and 14 to be supplied to the fuel cell 20, making it possible to supply hydrogen to the fuel cell 20 for a long period of time.

[0053] As described above, the hydrogen supply system 1 of the present invention supplies a heat medium to only some of the hydrogen storage alloy tanks 12, 13, and 14 among the multiple hydrogen storage alloy tanks 11, 12, 13, and 14, and preheats only the hydrogen storage alloy tanks 12, 13, and 14, before supplying hydrogen to the fuel cell 20. This makes it possible to supply high-pressure hydrogen when hydrogen supply to the fuel cell 20 begins.

[0054] Hydrogen is then transferred between the hydrogen storage alloy tanks 12, 13, and 14 to which the heat medium is supplied and the hydrogen storage alloy tank 11 to which the heat medium is not supplied. This prevents an excessive increase in the internal pressure of the hydrogen storage alloy tanks 12, 13, and 14 to which the heat medium is supplied. Furthermore, the hydrogen transferred to the hydrogen storage alloy tank 11 to which the heat medium is not supplied is stored in the hydrogen storage alloy contained in the hydrogen storage alloy tank 11, so the total flow rate of hydrogen that can be supplied to the fuel cell 20 does not decrease. Therefore, the hydrogen supply system 1 of the present invention makes it possible to supply high-pressure hydrogen at the start of hydrogen supply while preventing a decrease in the total flow rate of hydrogen that can be supplied to the fuel cell 20.

[0055] In addition, when the hydrogen released from the hydrogen storage alloy tanks 12, 13, and 14 is absorbed into the hydrogen storage alloy contained in the hydrogen storage alloy tank 11, the temperature of the hydrogen storage alloy tank 11 rises. Therefore, the hydrogen storage alloy tank 11 can be preheated while reducing the energy consumed to supply a heat medium to the hydrogen storage alloy tank 11.

[0056] The above-described embodiment can be modified as appropriate without departing from the scope of the present invention. For example, in the above-described embodiment, hydrogen is transferred between the hydrogen storage alloy tanks 12, 13, and 14 to which a heat medium is supplied and the hydrogen storage alloy tank 11 to which no heat medium is supplied only when the internal pressure of the hydrogen storage alloy tanks 12, 13, and 14 reaches or exceeds a reference value. However, this is not limited to this. Hydrogen may be transferred between the hydrogen storage alloy tanks 12, 13, and 14 to which a heat medium is supplied and the hydrogen storage alloy tank 11 to which no heat medium is supplied even when the internal pressure of the hydrogen storage alloy tanks 12, 13, and 14 is below the reference value. Even in this case, an excessive increase in the internal pressure of the hydrogen storage alloy tanks 12, 13, and 14 to which a heat medium is supplied can be suppressed.

[0057] In addition, in the above embodiment, the hydrogen supply system 1 is equipped with a safety valve that activates when the internal pressure of the hydrogen storage alloy tanks 11, 12, 13, and 14 exceeds a predetermined value, thereby reducing the internal pressure of the hydrogen storage alloy tanks 11, 12, 13, and 14, but it is not necessary to be equipped with a safety valve.

[0058] 1 Hydrogen supply system, 10 Hydrogen storage device, 11, 12, 13, 14 Hydrogen storage alloy tank, 15 Pressure gauge, 20 Fuel cell (hydrogen supply destination), 30 Control device, 40, 41, 42 Heat medium piping, 43, 44 Main piping, 43A, 43B, 43C, 43D, 44A, 44B, 44C, 44D Branch piping, 45A, 45B, 45C, 45D Valve, 50 Circulation device, 60, 60A, 60B, 60C, 60D, 60E Hydrogen piping, 61A, 61B, 61C, 61D, 61E Valve

Claims

1. A hydrogen supply system comprising: a plurality of hydrogen storage alloy tanks containing hydrogen storage alloys; heat medium piping connected to each of the hydrogen storage alloy tanks and through which a heat medium flows; and hydrogen piping connecting the plurality of hydrogen storage alloy tanks to each other and through which hydrogen released from the hydrogen storage alloy tanks flows, and which supplies hydrogen to a hydrogen supply destination, wherein, before supplying hydrogen to the hydrogen supply destination, the system supplies the heat medium to some of the plurality of hydrogen storage alloy tanks to preheat them, and transfers hydrogen between the hydrogen storage alloy tanks to which the heat medium is supplied and the hydrogen storage alloy tanks to which the heat medium is not supplied.

2. A hydrogen supply system as described in claim 1, further comprising a pressure gauge for measuring the internal pressure of each of the hydrogen storage alloy tanks, and when the internal pressure of the hydrogen storage alloy tank to which the heat medium is supplied reaches or exceeds a reference value, hydrogen in the hydrogen storage alloy tank to which the heat medium is supplied is moved to the hydrogen storage alloy tank to which the heat medium is not supplied.

3. A hydrogen supply system as described in claim 1, wherein, before hydrogen is transferred between the hydrogen storage alloy tanks, the hydrogen storage capacity of the hydrogen storage alloy tank to which the heat transfer medium is not supplied is smaller than the hydrogen storage capacity of the hydrogen storage alloy tank to which the heat transfer medium is supplied.

4. A hydrogen supply system as described in claim 2, further comprising a safety valve that operates when the internal pressure of the hydrogen storage alloy tank exceeds a predetermined value to reduce the internal pressure of the hydrogen storage alloy tank, and the reference value is smaller than the internal pressure value at which the safety valve operates.

5. The hydrogen supply system according to claim 1, wherein the heat medium is supplied to all of the hydrogen storage alloy tanks after hydrogen has been supplied to the hydrogen supply destinations.

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