JP2008261392A - Hydrogen supply apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To utilize hydrogen stored in a hydrogen storing metal alloy effectively. <P>SOLUTION: A hydrogen supply apparatus comprises a hydrogen tank 31 in which a hydrogen storing alloy 31a with hydrogen stored in advance is housed to supply hydrogen discharged from the hydrogen storing alloy 31a to a fuel cell 10, determines whether or not pressure within the hydrogen tank 31 is lower than a permissible lower limit, extracts residual hydrogen within the hydrogen storing alloy by decompressing the inside of the hydrogen tank 31 by a decompression pump 33 when the pressure within the hydrogen tank 31 is lower than the permissible lower limit, and supplies the extracted residual hydrogen to the fuel cell 10 by boosting pressure thereof by a booster pump 35. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hydrogen supply apparatus.

  2. Description of the Related Art There is a known hydrogen supply apparatus that includes a hydrogen tank that stores a hydrogen storage alloy in which hydrogen is stored in advance and that releases hydrogen from the hydrogen storage alloy and supplies the released hydrogen to a fuel cell (patent) Reference 1). When the hydrogen storage alloy is used as described above, the volume or space necessary for storing a certain amount of hydrogen can be reduced as compared with the case where a cylinder is used, and hydrogen can be stored safely.

JP 2004-253258 A

  However, even if the hydrogen tank is released to atmospheric pressure, for example, all the hydrogen stored in the hydrogen storage alloy cannot be released from the hydrogen storage alloy, and only hydrogen is stored in the hydrogen storage alloy. It will remain. That is, there is a problem that hydrogen stored in the hydrogen storage alloy cannot be used effectively.

  In order to solve the above-mentioned problems, according to the present invention, a hydrogen tank containing a hydrogen storage alloy in which hydrogen is stored in advance is provided, and hydrogen is released from the hydrogen storage alloy and the released hydrogen is supplied to a destination. The hydrogen supply apparatus is configured to supply a pressure reducing pump, and it is determined whether or not the pressure in the hydrogen tank has decreased below the allowable lower limit, and the pressure in the hydrogen tank has decreased beyond the allowable lower limit. In this case, the pressure inside the hydrogen tank is reduced by the pressure reducing pump to take out the remaining hydrogen in the hydrogen storage alloy, and the taken out remaining hydrogen is supplied to the supply destination.

  Hydrogen stored in the hydrogen storage alloy can be used effectively.

  FIG. 1 shows a case where the present invention is applied to a vehicle power generation system.

  Referring to FIG. 1, the power generation system 1 includes a fuel cell 10, an oxygen supply device 20 that supplies oxygen to the fuel cell 10, a hydrogen supply device 30 that supplies hydrogen to the fuel cell 10, and an electronic control unit 70. To do.

  The oxygen supply device 20 includes an oxygen source 21 such as the atmosphere. The oxygen source 21 is connected to the suction side of the oxygen pump 23 via an oxygen circulation pipe 22, and the discharge side of the oxygen pump 23 is connected to an oxygen supply pipe 24. To the fuel cell 10. An oxygen supply valve 25 composed of an electromagnetic valve is disposed in the oxygen supply pipe 24.

  The hydrogen supply device 30 includes a hydrogen tank 31 as a hydrogen source, and a hydrogen discharge port of the hydrogen tank 31 is connected to a suction side of a fluid pressure driven decompression pump 33 through a hydrogen discharge pipe 32. The discharge side of the decompression pump 33 is connected to the inflow side of a fluid pressure driven booster pump 35 via a hydrogen flow pipe 34, and the discharge side of the booster pump 35 stores a hydrogen buffer at high pressure via a hydrogen high pressure pipe 36. The hydrogen buffer 37 is connected to the fuel cell 10 through a hydrogen supply pipe 38. A hydrogen release valve 39 consisting of a solenoid valve with a pressure adjusting function is arranged in the hydrogen release pipe 32, a check valve 40 is arranged in the hydrogen high-pressure pipe 36, and an electromagnetic valve is arranged in the hydrogen supply pipe 38. A hydrogen supply valve 41 is arranged. Further, pressure sensors 42 and 43 for detecting the pressure in the hydrogen tank 31 and the hydrogen buffer 37 are attached to the hydrogen tank 31 and the hydrogen buffer 37, respectively.

  A hydrogen storage alloy 31 a is accommodated in the hydrogen tank 31. The hydrogen storage alloy 31a is made of, for example, a TiCrV material or a TiCrMn material, but may be made of other materials. The hydrogen tank 31 is composed of a pressure vessel. In the embodiment according to the present invention, hydrogen is filled in the hydrogen tank 31 in advance under a pressure higher than the equilibrium pressure at the time of occlusion of the hydrogen occlusion alloy 31a. In this case, a part of hydrogen is stored in the form of hydride in the hydrogen storage alloy 31a, and the rest is stored in the form of gas in the internal space of the hydrogen tank 31 around the hydrogen storage alloy 31a.

  The decompression pump 33 is for decompressing the inside of the hydrogen tank 31. In the embodiment according to the present invention, the decompression pump 33 can decompress the inside of the hydrogen tank 31 to a negative pressure. On the other hand, the booster pump 35 is for boosting and feeding hydrogen into the hydrogen buffer 37. In the embodiment according to the present invention, the booster pump 35 can boost hydrogen from several atmospheres to several tens of atmospheres.

  In the embodiment shown in FIG. 1, the power generation system 1 is mounted on an electrically driven vehicle 50. The vehicle 50 includes an electric motor 51 as a sole drive source, and an output shaft 52 of the electric motor 51 is connected to an axle 54 via a differential gear 53. Electric energy is supplied from the power generation system 1 to the electric motor 51. Further, the vehicle 50 includes a regeneration device 55 that regenerates vehicle braking energy. The regenerative device 55 includes, for example, a gear pump 56 attached to the output shaft 52 of the electric motor 51. The gear pump 56 compresses the working fluid in the low pressure chamber 57 and sends it into the high pressure chamber 58 during vehicle braking or deceleration. Therefore, a high pressure working fluid is stored in the high pressure chamber 58. The high-pressure chamber 58 is connected to the decompression pump 33 and the booster pump 35 via working fluid control valves 59 and 60 each composed of a solenoid valve with a pressure regulating function. The vehicle 50 can also be configured from a so-called hybrid vehicle including an electric motor 51 and an engine as drive sources.

  The electronic control unit 70 is composed of a digital computer and includes a ROM (read only memory) 72, a RAM (random access memory) 73, a CPU (microprocessor) 74, an input port 75 and an output port 76 which are connected to each other by a bidirectional bus 71. It comprises. The output voltages of the pressure sensors 42 and 43 are input to the input port 75 via the corresponding AD converters 77, respectively. The output port 76 is connected to the oxygen pump 23, the oxygen supply valve 25, the hydrogen release valve 39, the hydrogen supply valve 41, and the working fluid control valves 59 and 60 through corresponding drive circuits 78, which are connected from the electronic control unit 70. It is controlled based on the signal.

  When the fuel cell 10 should generate electricity, the oxygen supply valve 24 is opened, the oxygen pump 23 is operated, and the hydrogen supply valve 41 is opened. As a result, oxygen or air from the oxygen source 21 is supplied to the fuel cell 10 via the oxygen supply pipe 22, and hydrogen in the hydrogen buffer 37 is supplied to the fuel cell 10 via the hydrogen supply pipe 38.

  When hydrogen is to be supplied from the hydrogen tank 31, that is, for example, when the pressure in the hydrogen buffer 37 falls below the allowable lower limit, the hydrogen release valve 39 is opened. As a result, hydrogen stored in the internal space of the hydrogen tank 31 is released from the hydrogen tank 31, or hydrogen is released from the hydrogen storage alloy 31a and released from the hydrogen tank 31. An apparatus for heating the hydrogen storage alloy 31a may be provided in order to release hydrogen from the hydrogen storage alloy 31a. The released hydrogen is sequentially passed through the hydrogen release pipe 32, the hydrogen circulation pipe 34, and the hydrogen high-pressure pipe 36 to be filled in the hydrogen buffer 37. In this case, the decompression pump 33 and the booster pump 35 are deactivated, and hydrogen passes through the decompression pump 33 and the booster pump 35 without being affected by the decompression pump 33 and the booster pump 35.

When the hydrogen release from the hydrogen tank 31 is continued, the pressure PT in the hydrogen tank 31 decreases as shown in FIG. Next, as shown by X in FIG. 2, when the tank internal pressure PT falls below the allowable lower limit PX (for example, atmospheric pressure), the pressure reducing pump 33 and the pressure increasing pump 35 are operated. As a result, the inside of the hydrogen tank 31 is depressurized to a negative pressure PN (for example, about 0.13 Pa (10 ⁻³ torr)), whereby residual hydrogen in the hydrogen storage alloy 31a is taken out from the hydrogen storage alloy 31a. The extracted hydrogen is then boosted by the booster pump 35 and then supplied to the hydrogen buffer 37.

  Next, when the hydrogen tank 31 is filled with hydrogen and the hydrogen tank internal pressure PT becomes higher than the allowable lower limit PX, the pressure reducing pump 33 and the pressure increasing pump 35 are stopped.

  As described above, in the embodiment according to the present invention, the negative pressure is applied to the hydrogen storage alloy 31a to extract the hydrogen, so that the hydrogen stored in the hydrogen storage alloy 31a can be used effectively. Actually, when the vacuum pump 33 is operated, about 0.3 to 0.5 wt% of hydrogen can be taken out. Further, since a large amount of hydrogen is released from the hydrogen storage alloy 31a and the residual hydrogen in the hydrogen storage alloy 31a is reduced, a large amount of hydrogen is stored in the hydrogen storage alloy 31a when the hydrogen is filled in the next hydrogen tank 31. The deterioration of the hydrogen storage alloy 31 can also be suppressed. Furthermore, since the extracted hydrogen is boosted by the boost pump 35 and supplied to the hydrogen buffer 37, the hydrogen can be reliably supplied to the hydrogen buffer 37.

  Note that the decompression pump 33 and the booster pump 35 may be configured by an electric pump. However, in this case, it is necessary to generate electric power in order to take out the remaining hydrogen, that is, all of the taken out remaining hydrogen cannot be used for driving the vehicle.

  Therefore, in the embodiment according to the present invention, the pressure reducing pump 33 and the pressure increasing pump 35 are constituted by fluid pressure driven pumps, so that hydrogen is not consumed in order to take out residual hydrogen. However, the decompression pump 33 and the booster pump 35 are composed of pumps that use electricity or fluid pressure as a drive source, and the decompression pump 33 and the booster pump 35 are driven by electricity only when it cannot be driven only by the fluid pressure. You may make it do. In addition, at least one of the decompression pump 33 and the booster pump 35 can be constituted by a fluid pressure driven pump.

  FIG. 3 shows a hydrogen supply control routine of the embodiment according to the present invention. This routine is executed at predetermined time intervals.

  Referring to FIG. 3, first, at step 100, it is determined whether or not hydrogen should be supplied from the hydrogen tank 31 to the hydrogen buffer 37. When it is determined that hydrogen should not be supplied, the routine proceeds to step 101 where the hydrogen release valve 39 is closed. In subsequent step 102, the decompression pump 33 and the booster pump 35 are deactivated. On the other hand, when it is determined that hydrogen should be supplied, the routine proceeds from step 100 to step 103, where the hydrogen release valve 39 is opened. In the following step 104, it is determined whether or not the pressure PT in the hydrogen tank 31 has dropped below the allowable lower limit PX. When PT ≧ PX, the routine proceeds to step 102 where the operation of the pressure reducing pump 33 and the pressure increasing pump 35 is continued. On the other hand, when PT <PX, the routine proceeds from step 104 to step 105, the working fluid control valves 59, 60 are opened, and the pressure reducing pump 33 and the pressure increasing pump 35 are operated.

  FIG. 4 shows another embodiment according to the present invention. Referring to FIG. 4, the hydrogen supply device 30 includes an additional hydrogen tank 80. The hydrogen discharge port of the additional hydrogen tank 80 is connected to an additional hydrogen discharge pipe 81, and the additional hydrogen discharge pipe 81 is connected to the hydrogen flow pipe 34 between the pressure reduction pump 33 and the pressure increase pump 35. An additional hydrogen release valve 82 made up of an electromagnetic valve with a pressure regulating function is disposed in the additional hydrogen release pipe 81. In the example shown in FIG. 4, the hydrogen storage alloy is not accommodated in the additional hydrogen tank 80, but the hydrogen storage alloy can be accommodated in the additional hydrogen tank 80.

  As shown in FIG. 5, at the normal time when the pressure PT in the hydrogen tank 31 is higher than the allowable lower limit PX, the decompression pump 33 and the booster pump 35 are stopped as in the above-described embodiment. At this time, the additional hydrogen release valve 82 is normally closed, so that hydrogen is released from the hydrogen tank 31 and hydrogen is not released from the additional hydrogen tank 80. Next, as indicated by X in FIG. 5, when the pressure PT in the hydrogen tank 31 falls below the allowable lower limit PX, the pressure reducing pump 33 and the pressure increasing pump 35 are operated, and the additional hydrogen release valve 82 is opened. Is done. As a result, residual hydrogen is taken out from the hydrogen storage alloy 31 a in the hydrogen tank 31, and hydrogen is released from the additional hydrogen tank 80. These hydrogens are then boosted by a booster pump 35 and supplied to a hydrogen buffer 37.

  Next, when the hydrogen tank 31 is filled with hydrogen and the hydrogen tank internal pressure PT becomes higher than the allowable lower limit PX, the decompression pump 33 and the boost pump 35 are deactivated, and the additional hydrogen release valve 82 is closed.

  Even though the decompression pump 33 can extract the residual hydrogen from the hydrogen storage alloy 31a, the total amount of the extracted hydrogen may not be sufficient for the vehicle to travel a certain distance. Therefore, in another embodiment according to the present invention, an additional hydrogen tank 80 is provided, and when the residual hydrogen is taken out from the hydrogen storage alloy 31a by the decompression pump 33, hydrogen is additionally supplied from the additional hydrogen tank 80. Yes. If it does in this way, it will become possible for a vehicle to run reliably to a hydrogen stand, for example.

  FIG. 6 shows a hydrogen supply control routine of another embodiment according to the present invention. This routine is executed at predetermined time intervals.

  Referring to FIG. 6, first, at step 200, it is judged if hydrogen should be supplied from the hydrogen tank 31 to the hydrogen buffer 37. When it is determined that hydrogen should not be supplied, the routine proceeds to step 201 where the hydrogen release valve 39 and the additional hydrogen release valve 82 are closed. In the subsequent step 202, the decompression pump 33 and the booster pump 35 are deactivated. On the other hand, when it is determined that hydrogen should be supplied, the routine proceeds from step 200 to step 203, where the hydrogen release valve 39 is opened. In the next step 204, it is determined whether or not the pressure PT in the hydrogen tank 31 has dropped below the allowable lower limit PX. When PT ≧ PX, the routine proceeds to step 202 where the operation of the pressure reducing pump 33 and the pressure increasing pump 35 is continued. On the other hand, when PT <PX, the routine proceeds from step 204 to step 205, where the working fluid control valves 59, 60 are opened to operate the decompression pump 33 and the boost pump 35, and the additional hydrogen release valve 82 is opened. To be spoken.

  In each of the embodiments described so far, the pressure increasing pump 35 is also started at the same time when the pressure reducing pump 33 is started. However, for example, as shown in FIG. 7, when the pressure PT in the hydrogen tank 31 falls below a set pressure PY set higher than the allowable lower limit PX, only the booster pump 35 is started, and then the hydrogen tank The pressure reducing pump 33 may be started to operate when the pressure PT within 31 falls below the allowable lower limit PX.

1 is an overall view of a power generation system according to an embodiment of the present invention. It is a time chart explaining the Example by this invention. It is a flowchart for performing the hydrogen supply control routine of the Example by this invention. It is a general view of the electric power generation system of another Example by this invention. It is a time chart explaining another Example by this invention. It is a flowchart for performing the hydrogen supply control routine of another Example by this invention. It is a time chart explaining another Example by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Power generation system 10 Fuel cell 30 Hydrogen supply apparatus 31 Hydrogen tank 31a Hydrogen storage alloy 33 Pressure reduction pump 35 Pressure increase pump 37 Hydrogen buffer 50 Electric drive vehicle 55 Regenerative apparatus 80 Additional hydrogen tank

Claims (8)

  In a hydrogen supply apparatus comprising a hydrogen tank containing a hydrogen storage alloy in which hydrogen has been stored in advance, and discharging hydrogen from the hydrogen storage alloy and supplying the released hydrogen to a supply destination, a decompression pump It is determined whether or not the pressure in the hydrogen tank has dropped below the allowable lower limit, and when the pressure in the hydrogen tank has dropped below the allowable lower limit, the pressure in the hydrogen tank is reduced by the vacuum pump. A hydrogen supply device that extracts residual hydrogen from the hydrogen storage alloy and supplies the extracted residual hydrogen to a supply destination.   The hydrogen supply device according to claim 1, wherein the pressure inside the hydrogen tank is reduced to a negative pressure by the pressure reducing pump.   The hydrogen supply apparatus according to claim 1, further comprising a booster pump that boosts the extracted residual hydrogen and supplies the boosted residual hydrogen to the supply destination.   The hydrogen supply apparatus according to any one of claims 1 to 3, further comprising a hydrogen buffer that is disposed between the hydrogen tank and the supply destination and temporarily stores hydrogen.   An additional hydrogen tank storing hydrogen is further provided, and when the pressure in the hydrogen tank becomes lower than an allowable lower limit, the hydrogen in the additional hydrogen tank is supplied together with the remaining hydrogen taken out from the hydrogen tank. The hydrogen supply apparatus according to any one of claims 1 to 4, wherein the hydrogen supply apparatus is supplied first.   6. The vehicle according to claim 1, wherein the hydrogen supply device is provided in a vehicle provided with a regenerative device for regenerating vehicle braking energy, and the decompression pump is driven by the energy regenerated by the regenerative device. The hydrogen supply device according to claim 1.   The apparatus further comprises a booster pump that boosts the extracted residual hydrogen and supplies the boosted hydrogen to the supply destination, and drives at least one of the decompression pump and the booster pump with energy regenerated by the regeneration device. The hydrogen supply device according to claim 6.   The hydrogen supply apparatus according to any one of claims 1 to 7, wherein the supply destination is a fuel cell.

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