Hydrogen storage system, control device, and control method

Abstract

To provide a hydrogen storage system capable of filling a tank with hydrogen gas without calculating a hydrogen residual amount in the tank in advance.SOLUTION: A hydrogen storage system includes an alloy tank for occluding hydrogen gas, and a control device for controlling supply of hydrogen gas from a curdle to the alloy tank. The control device includes a change rate acquiring section for acquiring a time change rate of a hydrogen gas filling amount from the curdle to the alloy tank, and an end determining section for ending supply of hydrogen to the alloy tank when the time change rate is less than a predetermined threshold.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] Conventionally, in a method of replenishing hydrogen gas to a tank using a hydrogen storage alloy, a flow meter is installed in a pipe connecting the hydrogen gas supply source and the tank, and when a predetermined amount of hydrogen gas is filled in the tank, the supply is stopped (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional method, in order to fill the tank to full, there is a problem that in order to determine the filling hydrogen amount to be full, it is necessary to calculate the remaining hydrogen amount in the tank in advance, such as measuring the weight of the tank.

[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 filling hydrogen gas into a tank without calculating the remaining hydrogen amount in the tank in advance.

Means for Solving the Problems

[0006] This invention was made to solve the above-mentioned problems, and one aspect of the present invention comprises an alloy tank for storing hydrogen and a control device for controlling the supply of hydrogen gas from a cradle to the alloy tank, wherein the control device includes a rate of change acquisition unit for acquiring the rate of change over time of the amount of hydrogen gas filled from the cradle to the alloy tank, and an termination determination unit for terminating the supply of hydrogen to the alloy tank when the rate of change over time falls below a predetermined threshold. The rate of change acquisition unit acquires the pressure and temperature inside the cradle, calculates the remaining amount of hydrogen inside the cradle by substituting the acquired pressure, temperature, and internal volume of the cradle into the ideal gas law, and if this is not the first time the remaining amount of hydrogen has been calculated, subtracts the remaining amount of hydrogen from the previously calculated amount, and calculates the rate of change over time based on the subtraction result and the time elapsed from the previous calculation to the current calculation. It is a hydrogen storage system.

[0008] Another aspect of the present invention is: A control device for controlling the supply of hydrogen gas from a cradle to an alloy tank for hydrogen storage, comprising: a change rate acquisition unit that acquires the time rate of change of the amount of hydrogen gas filled from the cradle to the alloy tank; and a termination determination unit that terminates the supply of hydrogen to the alloy tank when the time rate of change falls below a predetermined threshold, wherein the change rate acquisition unit acquires the pressure and temperature inside the cradle, calculates the amount of hydrogen remaining inside the cradle based on substituting the acquired pressure, temperature and the internal volume of the cradle into the ideal gas law, subtracts the amount of hydrogen remaining from the amount of hydrogen remaining calculated in the previous calculation if it is not the first time, and calculates the time rate of change based on the subtraction result and the time from the previous calculation to the current calculation. .

[0010] Another aspect of the present invention is a control method for controlling the supply of hydrogen gas from a cradle to an alloy tank for hydrogen storage, comprising the steps of: obtaining the rate of change over time of the amount of hydrogen gas being filled from the cradle to the alloy tank; and terminating the supply of hydrogen to the alloy tank when the rate of change over time falls below a predetermined threshold, wherein in the step of obtaining the rate of change over time, the pressure and temperature inside the cradle are obtained, the amount of hydrogen remaining inside the cradle is calculated based on substituting the obtained pressure, temperature and the internal volume of the cradle into the ideal gas law; if the calculation of the amount of hydrogen remaining is not the first time, the amount of hydrogen remaining is subtracted from the amount of hydrogen remaining calculated in the previous calculation, and the rate of change over time is calculated based on the subtraction result and the time elapsed from the previous calculation to the current calculation. 。 [Effects of the Invention]

[0011] According to this invention, hydrogen gas can be filled into a tank without having to calculate the remaining amount of hydrogen in the tank beforehand. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic block diagram showing the configuration of a hydrogen cradle 10 and a hydrogen storage system 20 according to the first embodiment of this invention. [Figure 2] This is a flowchart illustrating the operation of the control device 209 in the same embodiment. [Figure 3] This is a flowchart illustrating the operation of the rate of change acquisition unit 212 and the termination determination unit 213 in the same embodiment. [Figure 4] This graph plots the amount of hydrogen gas filled and its rate of change over time in the same embodiment. [Figure 5] This is a schematic block diagram showing the configuration of the hydrogen cradle 10 and the hydrogen storage system 20 in a second embodiment of the present invention. [Figure 6] This is a flowchart illustrating the operation of the rate of change acquisition unit 212 and the termination determination unit 213 in the same embodiment. [Modes for carrying out the invention]

[0013] <First Embodiment> A first embodiment 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 cradle 10 and a hydrogen storage system 20 according to the first embodiment of the present invention. The hydrogen storage system 20 is a system that stores hydrogen for supply to fuel cells and the like using a hydrogen storage alloy. The hydrogen cradle 10 is made up of multiple bundled high-pressure gas containers and is used for transporting hydrogen gas. The hydrogen cradle 10 is connected to the hydrogen storage system 20 and supplies hydrogen to be filled into the hydrogen storage system 20.

[0014] The hydrogen cradle 10 comprises a cradle 101, a cradle pressure gauge 102, a cradle thermometer 103, a cradle gas pipe 104, and a cradle valve 105. The cradle 101 is a bundle of high-pressure gas containers filled with hydrogen gas. The cradle pressure gauge 102 measures the pressure of the hydrogen gas in the cradle 101. The cradle thermometer 103 directly or indirectly measures the temperature of the hydrogen gas in the cradle 101. The cradle gas pipe 104 is a gas pipe for supplying the hydrogen gas in the cradle 101 to the hydrogen storage system 20. The cradle valve 105 is provided on the cradle gas pipe 104 and controls the flow of hydrogen gas in the cradle gas pipe 104.

[0015] The hydrogen storage system 20 includes a connection section 201, a tank gas pipe 202, a purge gas pipe 203, a purge valve 204, a tank valve 205, a pressure reducing valve 206, an alloy tank 207, a tank pressure gauge 208, and a control device 209. The connection section 201 connects to a gas pipe for taking in hydrogen gas to be filled into the hydrogen storage system 20. A cradle gas pipe 104 is connected here. The tank gas pipe 202 is a gas pipe that connects the connection section 201 and the alloy tank 207, and supplies hydrogen gas supplied from the connection section 201 to the alloy tank 207.

[0016] The purge gas pipe 203 is a gas pipe that branches off from the tank gas pipe 202 between the connection part 201 and the tank valve 205. The purge gas pipe 203 is used to discharge any remaining air between the cradle valve 105 and the tank valve 205 when the hydrogen cradle 10 is connected to the connection part 201. The purge valve 204 is provided on the purge gas pipe 203 and controls the flow of gas within the purge gas pipe 203.

[0017] The tank valve 205 is located on the tank gas pipe 202 and controls the flow of hydrogen gas to the alloy tank 207 via the tank gas pipe 202. The pressure reducing valve 206 is located on the tank gas pipe 202 on the alloy tank 207 side of the tank valve 205 and reduces the pressure of the hydrogen gas being filled into the alloy tank 207. The alloy tank 207 has a hydrogen storage alloy and stores hydrogen gas in the hydrogen storage alloy. The tank pressure gauge 208 measures the pressure of the hydrogen gas in the alloy tank 207. The control device 209 controls the filling of hydrogen gas from the hydrogen cradle 10 to the hydrogen storage system 20.

[0018] The control device 209 includes a purge processing unit 210, a pressure reducing valve control unit 211, a change rate acquisition unit 212, and an end determination unit 213. Note that the candle pressure gauge 102 and the candle thermometer 103 may be provided in the control device 209. Before filling the hydrogen gas from the candle 101 to the alloy tank 207, the purge processing unit 210 repeatedly fills the hydrogen gas from the candle 101 into the candle gas pipe 104 and the tank gas pipe 202 connecting the candle 101 and the alloy tank 207 and discharges it to the outside air. For example, when the candle gas pipe 104 is connected to the connection part 201, the purge processing unit 210 opens the candle valve 105 and then repeatedly opens and closes the purge valve 204 a predetermined number of times to discharge the air in the gas pipe.

[0019] When filling the hydrogen gas into the hydrogen storage system 20, the pressure reducing valve control unit 211 controls the pressure reducing valve 206. For example, the pressure reducing valve control unit 211 controls the pressure reducing valve 206 so that the pressure of the hydrogen gas to be filled becomes 0.95 MPa. The change rate acquisition unit 212 acquires the time change rate of the filling amount of the hydrogen gas from the candle 101 to the alloy tank 207. For example, the change rate acquisition unit 212 may acquire the pressure and temperature in the candle 101 using the candle pressure gauge 102 and the candle thermometer 103, and calculate the time change rate of the filling amount of the hydrogen gas to the alloy tank 207 using the acquired pressure and temperature and the gas state equation. When the time change rate acquired by the change rate acquisition unit 212 is less than a predetermined threshold value, the end determination unit 213 ends the supply of the hydrogen gas to the alloy tank 207. Also, the end determination unit 213 may end the supply of the hydrogen gas based on the time of filling the hydrogen gas or the comparison between the pressure in the candle 101 and the pressure in the alloy tank 207. Note that the end determination unit 213 may end the supply of the hydrogen gas by closing the tank valve 205 or the candle valve 105.

[0020] Figure 2 is a flowchart for explaining the operation of the control device 209 in the present embodiment. First, when the cartridge gas pipe 104 is connected to the connection part 201 (step Sa1), the purge processing unit 210 opens the cartridge valve 105 (step Sa2). Next, the purge processing unit 210 repeats the opening and closing of the purge valve 204 a predetermined number of times (step Sa3). Thereby, the air between the cartridge valve 105 and the tank valve 205 can be replaced with hydrogen gas, and the alloy tank 207 can be prevented from being filled with air.

[0021] Next, the purge processing unit 210 closes the purge valve 204, controls the pressure reducing valve 206 so that the pressure in the alloy tank 207 becomes a predetermined value (for example, 0.95 MPaG), and opens the tank valve 205 (step Sa4). Thereby, hydrogen gas is filled into the alloy tank 207. The pressure reducing valve control unit 211 controls the pressure reducing valve 206 so that the pressure in the alloy tank 207 indicated by the tank pressure gauge 208 becomes a predetermined value (for example, 0.95 MPaG) until the end determination unit 213 determines the end of hydrogen gas filling (step Sa5). When the end determination unit 213 determines the end of hydrogen gas filling (step Sa6-Yes), it closes the cartridge valve 105 and the tank valve 205, ends the hydrogen gas filling, opens the purge valve 204, and reduces the pressure (step Sa7).

[0022] Figure 3 is a flowchart for explaining the operations of the change rate acquisition unit 212 and the end determination unit 213 in the present embodiment. The flowchart of Figure 3 corresponds to step Sa6 in Figure 2. First, the change rate acquisition unit 212 acquires the pressure and temperature in the cartridge 101 (step Sb1). Specifically, the change rate acquisition unit 212 acquires the measurement results of the cartridge pressure gauge 102 and the cartridge thermometer 103. Next, the change rate acquisition unit 212 substitutes the pressure and temperature in the cartridge 101 and the internal volume of the cartridge 101 into the gas state equation to calculate the remaining hydrogen amount in the cartridge 101 (step Sb2). The unit of the calculated remaining hydrogen amount may be normal legislative meter (Nm 3 ) or kilogram (Kg) or other units.

[0023] If the calculation of the remaining hydrogen amount in step Sb2 is the first time (step Sb3-Yes), the process proceeds to step Sb6. If the calculation of the remaining hydrogen amount is not the first time (step Sb3-No), the change rate acquisition unit 212 calculates the time rate of change of the amount of hydrogen to be filled into the alloy tank 207 (step Sb4). For example, the change rate acquisition unit 212 first subtracts the amount of hydrogen calculated this time from the amount of hydrogen calculated last time, and then divides the result of this subtraction by the time interval from the last calculation to the current calculation to calculate the time rate of change of the amount of hydrogen to be filled.

[0024] Next, the termination determination unit 213 determines whether the rate of change of the hydrogen filling amount calculated in step Sb4 is less than a predetermined threshold (step Sb5). If it is determined to be less than the threshold (step Sb5-Yes), the process proceeds to step Sa6, Yes, in Figure 2. If it is determined to be not less than the threshold (step Sb5-No), the termination determination unit 213 determines whether the time spent filling with hydrogen gas exceeds a predetermined threshold (for example, 2 hours) (step Sb6).

[0025] If it is determined that the threshold has been exceeded (step Sb6-Yes), the process proceeds to step Sa6, Yes, in Figure 2. If it is determined that the threshold has not been exceeded (step Sb6-No), the termination determination unit 213 determines whether the pressure in the alloy tank 207 is equal to or greater than the pressure in the cradle 101 (step Sb7). If it is determined that the pressure is equal to or greater than the pressure in the cradle 101 (step Sb7-Yes), the process proceeds to step Sa6, Yes, in Figure 2. If it is determined that the pressure is not equal to or greater than the pressure in the cradle 101 (step Sb7-No), the process proceeds to step Sa6, No, in Figure 2.

[0026] Figure 4 is a graph plotting the amount of hydrogen gas filled and its rate of change over time in this embodiment. In Figure 4, Example 1 is filled with 20 Nm of hydrogen gas into the alloy tank 207. 3Example 1 is an example where filling begins with hydrogen gas already absorbed into the tank, and the tank becomes full after absorbing 80 Nm3 of hydrogen gas. Example 2 is an example where filling begins with no hydrogen gas absorbed into the alloy tank 207, and the tank becomes full after absorbing 100 Nm3 of hydrogen gas. As shown in Figure 4, in both Example 1 and Example 2, when the rate of change over time falls below 0.005, it takes 3 to 5 Nm3 to reach full capacity. 3 As such, if the threshold in step Sb5 is set to 0.005, the tank can be filled to about 95% of its capacity. In this way, by using the rate of change of the filling amount over time, it is possible to determine the end of filling regardless of the amount of hydrogen gas remaining in the alloy tank 207. Therefore, hydrogen gas can be filled into the alloy tank 207 without pre-calculating the amount of hydrogen remaining in the alloy tank 207.

[0027] <Second Embodiment> In the first embodiment, the rate of change over time of the filling amount was calculated from the change in the hydrogen remaining in the cradle 101, which was calculated using the measurement results of the cradle pressure gauge 102 and the cradle thermometer 103. In the second embodiment, the flow rate measured by the flow meter is used as the rate of change over time of the filling amount. Here, only the parts that differ from the first embodiment will be described.

[0028] Figure 5 is a schematic block diagram showing the configuration of the hydrogen cradle 10 and hydrogen storage system 20 in a second embodiment of the present invention. It differs from Figure 1 in that it does not have a cradle pressure gauge 102 and a cradle thermometer 103, and has a flow meter 214 in the portion of the tank gas pipe 202 between the pressure reducing valve 206 and the alloy tank 207. This flow meter 214 measures the flow rate of hydrogen gas filling the alloy tank 207.

[0029] Figure 6 is a flowchart illustrating the operation of the rate of change acquisition unit 212 and the termination determination unit 213 in this embodiment. It differs from the flowchart in Figure 3 in that it does not have steps Sb1 to Sb5 and has steps Sc1 and Sc2. First, the rate of change acquisition unit 212 acquires the flow rate measured by the flow meter 214 (step Sc1). Next, the termination determination unit 213 determines whether the flow rate acquired in step Sc1 is less than a predetermined threshold (step Sc2). If it is determined to be less than the threshold (step Sc2-Yes), the process proceeds to step Sa6, Yes in Figure 2. If it is determined to be not less than the threshold (step Sc5-No), the process proceeds to step Sb6. Thus, even when using the flow meter 214, hydrogen can be filled into the alloy tank 207 without pre-calculating the remaining amount of hydrogen in the alloy tank 207, similar to the first embodiment.

[0030] Alternatively, the control device 209 may be implemented by recording a program for realizing the functions of the control device 209 in Figures 1 and 5 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.

[0031] 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.

[0032] 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]

[0033] 101 Cadre 102 Caddle pressure gauge 103 Caddle Thermometer 104 Caddle gas pipe 105 Caddle Valve 201 Connection part 202 Tank gas pipe 203 Purge gas pipe 204 Purge Valve 205 Tank Valve 206 Pressure Reducing Valve 207 Alloy Tank 208 Tank pressure gauge 209 Control device 210 Purge Processing Unit 211 Pressure Reducing Valve Control Unit 212 Change Rate Acquisition Unit 213 Termination Determination Unit 214 Flow meter

Claims

1. A hydrogen-absorbing alloy tank, A control device for controlling the supply of hydrogen gas from the cradle to the alloy tank. Equipped with, The control device is A change rate acquisition unit that acquires the time rate of change of the amount of hydrogen gas filled from the cradle to the alloy tank, When the aforementioned rate of change over time falls below a predetermined threshold, the termination determination unit terminates the supply of hydrogen to the alloy tank. Equipped with, The hydrogen storage system includes a change rate acquisition unit that acquires the pressure and temperature inside the cradle, calculates the remaining amount of hydrogen inside the cradle by substituting the acquired pressure, temperature, and internal volume of the cradle into the ideal gas law, and, if the calculation of the remaining amount of hydrogen is not the first time, subtracts the remaining amount of hydrogen from the previously calculated amount of hydrogen, and calculates the time change rate based on the subtraction result and the time elapsed from the previous calculation to the current calculation.

2. A control device for controlling the supply of hydrogen gas from a cradle to an alloy tank that absorbs hydrogen, A change rate acquisition unit that acquires the time rate of change of the amount of hydrogen gas filled from the cradle to the alloy tank, When the aforementioned rate of change over time falls below a predetermined threshold, the termination determination unit terminates the supply of hydrogen to the alloy tank. Equipped with, The change rate acquisition unit acquires the pressure and temperature inside the cradle, calculates the remaining amount of hydrogen inside the cradle by substituting the acquired pressure, temperature, and internal volume of the cradle into the ideal gas law, and if the calculation of the remaining amount of hydrogen is not the first time, subtracts the remaining amount of hydrogen from the previously calculated amount of hydrogen, and calculates the time change rate based on the subtraction result and the time from the previous calculation to the current calculation.

3. A control method for controlling the supply of hydrogen gas from a cradle to an alloy tank for hydrogen storage, The steps include obtaining the time rate of change of the amount of hydrogen gas filled from the cradle to the alloy tank, The step of ending the supply of hydrogen to the alloy tank when the rate of change over time falls below a predetermined threshold, and It has, A control method that, in the step of obtaining the rate of change over time, obtains the pressure and temperature inside the cradle, calculates the amount of hydrogen remaining inside the cradle by substituting the obtained pressure, temperature and the internal volume of the cradle into the ideal gas law, and, if it is not the first time the amount of hydrogen remaining is calculated, subtracts the amount of hydrogen remaining from the amount of hydrogen remaining calculated in the previous calculation, and calculates the rate of change over time based on the subtraction result and the time elapsed from the previous calculation to the current calculation.

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