Hydrogen storage system, control device, and control method

Abstract

To provide a hydrogen storage system capable of suppressing required cooling capacity.SOLUTION: A hydrogen storage system includes a plurality of alloy tanks for occluding hydrogen gas, and a control device for controlling filling of the hydrogen gas in the plurality of alloy tanks. The control device makes timing for starting the filling of the hydrogen gas to be different from one another among the plurality of the alloy tanks.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a hydrogen storage system, a control device, and a control method.

Background Art

[0002] When hydrogen is stored in a hydrogen storage alloy, reaction heat is generated, so it is necessary to cool the hydrogen storage alloy (see, for example, Patent Document 1). For example, when filling a hydrogen storage alloy with hydrogen from a mobile hydrogen candle, a large amount of reaction heat is generated.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when the temperature of the hydrogen storage alloy rises, the amount of hydrogen that can be stored decreases. Therefore, when storing a large amount of hydrogen in a hydrogen storage alloy tank from a hydrogen candle or the like, a cooling system for the hydrogen storage alloy tank having a large cooling capacity is required to remove a large amount of reaction heat, which is a problem.

[0005] The present invention has been made in view of such circumstances, and provides a hydrogen storage system, a control device, and a control method capable of suppressing the required cooling capacity.

Means for Solving the Problems

[0006] This invention has been made to solve the above-described problems. One aspect of the present invention includes a plurality of alloy tanks that store hydrogen gas, and a control device that controls the filling of hydrogen gas into the plurality of alloy tanks. A heat exchanger used in common with the aforementioned multiple alloy tanks, and The heat exchanger is provided with a heat transfer medium pipeline connecting it to the plurality of alloy tanks, which circulates a heat transfer medium for cooling the plurality of alloy tanks.The control device is a hydrogen storage system that causes the timing of starting hydrogen gas filling to differ among the plurality of alloy tanks, and starts filling the other alloy tanks with hydrogen gas while one of the plurality of alloy tanks is being filled with hydrogen gas.

[0007] Another aspect of the present invention is the hydrogen storage system described above, wherein the control device cools the plurality of alloy tanks. The aforementioned When the temperature of the heat transfer medium exceeds a predetermined threshold, the filling of hydrogen gas into the plurality of alloy tanks is interrupted.

[0009] Another aspect of the present invention is the hydrogen storage system described above, wherein the control device starts filling the other alloy tanks with hydrogen gas after it has finished filling one of the plurality of alloy tanks with hydrogen gas.

[0010] Another aspect of the present invention relates to a plurality of alloy tanks for storing hydrogen gas. In a hydrogen storage system, the plurality of alloy tanks are provided with a heat exchanger used in common to the plurality of alloy tanks, via a heat transfer pipeline that circulates a heat transfer medium for cooling the plurality of alloy tanks. A control device for controlling the filling of hydrogen gas into a plurality of alloy tanks, wherein the timing for starting hydrogen gas filling differs among the plurality of alloy tanks, and the control device starts filling the other alloy tanks with hydrogen gas while one of the plurality of alloy tanks is being filled with hydrogen gas.

[0011] Another aspect of the present invention relates to a plurality of alloy tanks for storing hydrogen gas. In a hydrogen storage system, the plurality of alloy tanks are provided with a heat exchanger used in common to the plurality of alloy tanks, via a heat transfer pipeline that circulates a heat transfer medium for cooling the plurality of alloy tanks. A control method for controlling the filling of hydrogen gas into a plurality of alloy tanks, wherein the timing of starting hydrogen gas filling differs among the plurality of alloy tanks, and while hydrogen gas is being filled into one of the plurality of alloy tanks, the filling of hydrogen gas into the other alloy tanks is started. [Effects of the Invention]

[0012] This invention makes it possible to reduce the cooling capacity required in a hydrogen storage system. [Brief explanation of the drawing]

[0013] [Figure 1]This is a schematic block diagram showing the configuration of a hydrogen storage system 100 according to one embodiment of the present invention. [Figure 2] This is a flowchart illustrating the operation of the control device 105 in the same embodiment. [Figure 3] This graph shows the time transition of the heat exchanger inlet temperature in the same embodiment and comparative example. [Figure 4] This is a flowchart illustrating the operation of the control device 105 in the second embodiment of this invention. [Modes for carrying out the invention]

[0014] <First Embodiment> Embodiments of the present invention will be described below with reference to the drawings. Figure 1 is a schematic block diagram showing the configuration of a hydrogen storage system 100 according to one embodiment of the present invention. The hydrogen storage system 100 is a system that stores hydrogen for supply to fuel cells and the like using a hydrogen storage alloy. The hydrogen storage system 100 comprises alloy tanks 101, 102, 103, 104, a control device 105, a hydrogen gas pipeline 106, valves V, V1, V2, V3, V4, and a tank cooling system 110. Each of the alloy tanks 101, 102, 103, and 104 has a hydrogen storage alloy, and hydrogen gas is absorbed into the hydrogen storage alloy. The control device 105 controls the filling of hydrogen gas into the alloy tanks 101, 102, 103, and 104. The control device 105 causes the timing of starting hydrogen gas filling to differ among the alloy tanks 101, 102, 103, and 104.

[0015] The hydrogen gas pipeline 106 is a pipeline for filling alloy tanks 101, 102, 103, and 104 with hydrogen gas from a hydrogen cradle that stores hydrogen gas. A hydrogen cradle is connected to one end of the hydrogen gas pipeline 106. The other end of the hydrogen gas pipeline 106 branches off and connects to alloy tanks 101, 102, 103, and 104. Valves V are installed in the section of the hydrogen gas pipeline 106 before it branches off. Valves V1 are installed in the section of the hydrogen gas pipeline 106 that branches off and connects to alloy tank 101, valve V2 is installed in the section that connects to alloy tank 102, valve V3 is installed in the section that connects to alloy tank 103, and valve V4 is installed in the section that connects to alloy tank 104. As such, valves V1, V2, V3, and V4 are installed corresponding to each of the alloy tanks 101, 102, 103, and 104, allowing control over whether or not hydrogen gas is filled into each of the alloy tanks 101, 102, 103, and 104.

[0016] Alloy tanks 101, 102, 103, and 104 generate reaction heat when storing hydrogen gas. The tank cooling system 110 removes this reaction heat. The tank cooling system 110 includes a primary heat transfer medium pipeline 111, a thermometer 112, a heat exchanger 113, a pump 114, a secondary heat transfer medium pipeline 115, a cooling device 116, and a pump 117.

[0017] The primary heat medium pipeline 111 is a pipeline that circulates the heat medium for cooling the alloy tanks 101, 102, 103, and 104 between the alloy tanks 101, 102, 103, 104 and the heat exchanger 113. The thermometer 112 is installed near the entrance of the primary heat medium pipeline 111 to the heat exchanger 113 and measures the temperature of the heat medium flowing into the heat exchanger 113 (heat exchanger inlet temperature). The pump 114 creates the flow of the heat medium in the primary heat medium pipeline 111. The heat exchanger 113 performs heat exchange between the heat medium flowing in the primary heat medium pipeline 111 and the heat medium flowing in the secondary heat medium pipeline 115, and cools the heat medium in the primary heat medium pipeline 111. The secondary heat medium pipeline 115 is a pipeline that circulates the heat medium between the heat exchanger 113 and the cooling device 116. The cooling device 116 cools the heat medium flowing in the secondary heat medium pipeline 115. The pump 117 creates the flow of the heat medium in the secondary heat medium pipeline 115.

[0018] Figure 2 is a flowchart for explaining the operation of the control device 105 in the present embodiment. When the hydrogen burner is connected to the hydrogen gas pipeline 106 and the valve V is opened to start the supply of hydrogen gas, with n = 1, the control device 105 opens the valve Vn (step Sa1). Thereby, the filling of hydrogen gas into the alloy tank 101 is started. After a certain period of time has elapsed, the control device 105 acquires the heat exchanger inlet temperature measured by the thermometer 112 (step Sa2). Next, the control device 105 determines whether or not the acquired heat exchanger inlet temperature is less than or equal to the threshold value Xt (step Sa3). The threshold value Xt is a predetermined value, for example, a value between 30°C and 80°C.

[0019] In step Sa3, when it is determined that the value is not less than the threshold value Xt, that is, it exceeds the threshold value Xt, the control device 105 closes the valve Vn (step Sa9), interrupts the filling, and after a certain period of time has elapsed, the process returns to step Sa1. On the other hand, in step Sa3, when it is determined that the value is less than or equal to the threshold value Xt, the control device 105 determines whether or not a predetermined threshold time has elapsed since the valve Vn was opened (step Sa4). In step Sa4, when it is determined that the threshold time has not elapsed (step Sa4 - No), after a certain period of time has elapsed, the process returns to step Sa2. On the other hand, in step Sa4, when it is determined that the threshold time has elapsed (step Sa4 - Yes), the control device 105 opens the valve Vn+1 (step Sa5) and sets n = n + 1. Here, the threshold time is a value smaller than the value obtained by dividing the upper limit value T of the total filling time (for example, 2 hours) by the number A of the alloy tanks 101, 102, 103, 104.

[0020] Next, the control device 105 determines whether or not a total of the upper limit value T of the filling time has elapsed since the start of the supply of hydrogen gas (step Sa6). In step Sa6, when it is determined that the time has not elapsed (step Sa6 - No), after a certain period of time has elapsed, the process returns to step Sa2. On the other hand, in step Sa6, when it is determined that the time has elapsed (step Sa6 - Yes), the control device 105 closes the valve V and ends the supply of hydrogen gas (step Sa7), and opens the valves V1, V2, V3, V4 (step Sa8).

[0021] In this way, since the valves V1, V2, V3, V4 are opened at intervals of the threshold time, the hydrogen gas filling of the alloy tanks 101, 102, 103, 104 is started at intervals of the threshold time. Note that the condition in step Sa4 is set to the elapse of the threshold time, but it may be that the inlet temperature of the heat exchanger is on a downward trend, the inlet temperature of the heat exchanger is below a certain temperature, or a combination of a plurality of these and the elapse of the threshold time. Further, the threshold time may be changed depending on the value of n, such as increasing as the value of n increases.

[0022] Figure 3 is a graph showing the time transition of the heat exchanger inlet temperature in this embodiment and in a comparative example. In the graph in Figure 3, the horizontal axis is time and the vertical axis is the heat exchanger inlet temperature (°C). The heat exchanger inlet temperature in this embodiment is shown in graph L1. As shown in graph L1, the time transition of the heat exchanger inlet temperature in this embodiment repeats an increase and decrease at threshold time intervals. Graph L2 of the comparative example shows the time transition of the heat exchanger inlet temperature when hydrogen gas is simultaneously filled into alloy tanks 101, 102, 103, and 104. In this case, the temperature rises sharply immediately after the start of filling. Thus, in this embodiment, a rapid temperature rise can be suppressed, and therefore the cooling capacity required of the tank cooling system 110 can be reduced.

[0023] <Second Embodiment> In the first embodiment, valve Vn was left open while the next valve Vn+1 was opened. However, in the second embodiment, valve Vn was closed before opening the next valve Vn+1. The configuration of the hydrogen storage system 100 in the second embodiment is the same as in Figure 1. Only the differences from the first embodiment will be described here.

[0024] Figure 4 is a flowchart illustrating the operation of the control device 105 in a second embodiment of the present invention. The flowchart in Figure 4 differs from that in Figure 2 in that step Sb1 is inserted between steps Sa4 and Sa5. In step Sb1, the control device 105 closes valve Vn. Even in this manner, the temperature rise can be suppressed, as in the first embodiment, and thus the cooling capacity required of the tank cooling system 110 can be reduced.

[0025] In the embodiments described above, there are four alloy tanks 101-104 and four valves V1-V4, but there may be more than four, and not necessarily four. Also, each of the alloy tanks 101-104 may be composed of multiple alloy tanks.

[0026] Alternatively, the control device 105 may be implemented by recording a program for realizing the functions of the control device 105 in Figure 1 onto a computer-readable recording medium, and then loading and executing the program recorded on this recording medium into a computer system. The term "computer system" here includes hardware such as the operating system and peripheral devices.

[0027] Furthermore, "computer-readable recording media" refers to portable media such as flexible disks, magneto-optical disks, ROMs, and CD-ROMs, as well as storage devices such as hard disks built into computer systems. Moreover, "computer-readable recording media" also includes those that dynamically hold programs for a short period of time, such as communication lines used when transmitting programs over networks such as the Internet or communication lines such as telephone lines, and those that hold programs for a certain period of time, such as volatile memory inside computer systems that act as servers or clients in such cases. In addition, the above-mentioned programs may be for the purpose of realizing some of the functions described above, and may also be able to realize the above-mentioned functions in combination with programs already recorded in the computer system.

[0028] While embodiments of this invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and may include design modifications and the like that do not depart from the spirit of this invention. [Explanation of symbols]

[0029] 100 Hydrogen Storage Systems 101, 102, 103, 104 Alloy Tanks 105 Control device 106 Hydrogen gas pipeline 110 Tank Cooling System 111 Primary heat transfer pipe 112 Thermometer 113 Heat exchanger 114, 117 pumps 115 Secondary heat transfer pipe 116 Cooling device V, V1, V2, V3, V4 valves

Claims

1. Multiple alloy tanks for storing hydrogen gas, A control device for controlling the filling of hydrogen gas into the plurality of alloy tanks, The tank comprises a heat exchanger used in common with the aforementioned plurality of alloy tanks, The heat exchanger is provided with a heat transfer medium pipeline connecting it to the plurality of alloy tanks, which circulates a heat transfer medium for cooling the plurality of alloy tanks. The control device causes the timing for starting hydrogen gas filling to differ among the plurality of alloy tanks. While filling one of the plurality of alloy tanks with hydrogen gas, start filling the other alloy tanks with hydrogen gas. Hydrogen storage system.

2. The hydrogen storage system according to claim 1, wherein the control device interrupts the filling of hydrogen gas into the plurality of alloy tanks when the temperature of the heat transfer medium that cools the plurality of alloy tanks exceeds a predetermined threshold.

3. A control device for controlling the filling of hydrogen gas into a plurality of alloy tanks in a hydrogen storage system, wherein the plurality of alloy tanks for storing hydrogen gas and a heat exchanger used in common to the plurality of alloy tanks are provided via a heat transfer medium pipeline for circulating a heat transfer medium for cooling the plurality of alloy tanks, wherein the control device causes the timing of starting hydrogen gas filling to differ among the plurality of alloy tanks, and starts filling another alloy tank with hydrogen gas while one of the plurality of alloy tanks is being filled with hydrogen gas.

4. A control method for controlling the filling of hydrogen gas into a plurality of alloy tanks in a hydrogen storage system, wherein the plurality of alloy tanks for storing hydrogen gas and a heat exchanger used in common to the plurality of alloy tanks are provided via a heat transfer medium pipeline for circulating a heat transfer medium to cool the plurality of alloy tanks, wherein the timing of starting hydrogen gas filling differs among the plurality of alloy tanks, and while hydrogen gas is being filled into one of the plurality of alloy tanks, the filling of hydrogen gas into another alloy tank is started.

Images