JP2010218802A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system discharging water stored in a tank from a drainpipe by vaporizing the water without using a drainage pump. <P>SOLUTION: The drainpipe 46 for discharging a mixed gas to the atmosphere is arranged in a gas-liquid separator. A choked section 46a is prepared in the middle of the drainpipe 46, and a lead pipe 50a for leading the water stored in the tank 50 to the choked section 46a is connected with the choked section 46a. Then, upon leading the water from the lead pipe 50a into the small diameter section 46b of the choked section 46a, the water led to a small diameter section 46b is vaporized with the mixed gas wherein its flow velocity is rapidly accelerated by passing through the choked section 46a. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel cell system.

  In recent years, electric vehicles that use electricity as a power source to suppress global warming due to exhaust gas, and driving wheels are driven by motors at start-up and low-speed range to reduce fuel consumption and exhaust gas, and in the middle-high speed range A so-called hybrid vehicle in which driving wheels are driven by an engine (internal combustion engine) has been put into practical use. In addition, an electric vehicle (fuel cell vehicle) that uses a fuel cell instead of a battery as a power source has been partially put into practical use. In a fuel cell system mounted on a fuel cell vehicle, hydrogen and air (oxygen) are supplied to the fuel cell to generate an electromotive force by an electrochemical reaction, and water is generated by the reaction of hydrogen and oxygen. Therefore, the exhaust gas contains a large amount of water. The water contained in the exhaust gas is separated by a gas-liquid separator, the exhaust gas excluding water (air off gas) is discharged from the exhaust passage, and the water is discharged to the outside through, for example, an external exhaust valve. Yes.

  In the case of a vehicle traveling outdoors, if the water stored in the tank is little by little, it may be discharged while traveling. However, if a large amount is discharged, it is not preferable because the road surface etc. becomes flooded. . In addition, in the case of an indoor work vehicle or a vehicle such as a forklift that reciprocates between indoors and outdoors on the premises, if the water in the tank is discharged indoors, the floor (floor) gets wet with water. It is not preferable. Then, it is possible to atomize the water produced | generated with the fuel cell, and to discharge the atomized water to air | atmosphere (for example, refer patent document 1). The generated water discharge device of Patent Document 1 is equipped with an electric drain pump that sucks water stored in a tank and pressurizes the sucked water, and discharges water discharged from the drain pump through a micro nozzle. By spraying from the outlet, water is atomized and discharged to the outside of the vehicle body. In this way, the discharged water is prevented from being diffused in the atmosphere and getting wet on the road surface and floor.

JP 2007-141475 A

  However, in the fuel cell system provided with the generated water discharge device of Patent Document 1, it is necessary to pressurize the water with a drain pump in order to atomize the water. For this reason, in the generated water discharge apparatus of patent document 1, while the energy for the drive of a drainage pump is required, the space which installs a drainage pump is required. In addition, since the drainage pump is a movable part, there is a problem of durability of the drainage pump, and there is a problem that the cost for installing the drainage pump is high.

  An object of the present invention is to provide a fuel cell system capable of atomizing water stored in a tank without using a drain pump and discharging the water from a discharge pipe.

  In order to achieve the above object, the invention described in claim 1 is a fuel cell, a gas-liquid separator that separates water from off-gas discharged from the fuel cell, and water separated by the gas-liquid separator. A tank capable of storing water, a gas from which water has been separated by the gas-liquid separator is discharged from the gas-liquid separator, and a discharge pipe having a venturi section, and water stored in the tank is introduced into the venturi section The water stored in the tank is atomized by being introduced into the venturi section via the introduction pipe and discharged from the discharge pipe as atomized water. Is the gist.

  According to the present invention, in the discharge pipe, the pressure at the most constricted portion in the venturi section is lower than the pressure on the upstream side and the downstream side of the constricted portion. Therefore, the flow velocity of the gas passing through the discharge pipe increases rapidly when passing through the venturi section. In addition, the pressure at the most constricted part in the venturi section is lower than the pressure in the tank, and a pressure difference is generated at the connection section between the venturi section and the introduction pipe, and the pressure is stored in the tank by the venturi effect. Water is sucked into the venturi section through the introduction pipe. Therefore, by introducing the water stored in the tank into the venturi portion through the introduction pipe, the water introduced into the venturi portion by the gas whose flow velocity has been rapidly increased is atomized to become atomized water. The atomized water is discharged to the atmosphere along with the gas through the discharge pipe. Therefore, the water stored in the tank can be atomized and discharged into the atmosphere as atomized water simply by providing the venturi portion in the discharge pipe without using the drain pump.

  According to a second aspect of the present invention, in the first aspect of the present invention, the gas-liquid separator is connected to a hydrogen pipe that guides the anode off-gas from the fuel cell to the gas-liquid separator. The gist of the gas-liquid separator is that it has a dilution function of diluting hydrogen contained in the anode offgas.

  According to the present invention, when anode purge is performed to prevent or suppress reduction in power generation efficiency of the fuel cell, the anode off-gas is introduced into the gas-liquid separator and the gas-liquid separator having a dilution function is provided. As a result, hydrogen contained in the anode off-gas is diluted. Therefore, the configuration of the fuel cell system can be made compact compared to a configuration in which a diluter for diluting hydrogen is separately provided.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the discharge port of the discharge pipe is provided at a position where the atomized water is vaporized by a heat source. This is the gist.

  According to this invention, the atomized water discharged from the discharge pipe is discharged toward the heat source. Then, the atomized water is heated and vaporized by the high-temperature heat generated from the heat source. Therefore, the atomized water discharged from the discharge pipe can be vaporized by the heat source and discharged to the atmosphere.

The gist of the invention according to claim 4 is that, in the invention according to any one of claims 1 to 3, the fuel cell system is mounted on an indoor industrial vehicle.
According to the present invention, an indoor industrial vehicle that runs or works using a fuel cell as a drive source can atomize the water stored in the tank without using a drain pump and discharge it to the atmosphere. It is possible to prevent the water from dripping and getting the floor wet.

  According to this invention, the water stored in the tank can be atomized and discharged from the discharge pipe without using the drain pump.

1 is a schematic side view of a forklift according to a first embodiment. The schematic block diagram of a fuel cell system. The plane sectional view of a gas liquid separator. The model perspective view which shows a gas-liquid separator and a tank. The expanded sectional view which expands and shows the venturi part of a discharge pipe. The partial schematic block diagram of the fuel cell system in 2nd Embodiment.

(First embodiment)
A first embodiment in which the present invention is embodied in a fuel cell system for a forklift used as an indoor industrial vehicle will be described below with reference to FIGS. In FIG. 1, “front”, “rear”, “left”, “right”, “upper”, and “lower” are based on the state in which the forklift driver faces the front of the vehicle (forward direction). In this case, “front”, “rear”, “left”, “right”, “upper”, “lower” are shown.

  As shown in FIG. 1, a forklift 10 as an indoor industrial vehicle is provided with a mast 12 at the front portion of a vehicle body 11. The mast 12 is equipped with a fork 13 that can be lifted and lowered via a lift bracket 14, and the fork 13 is lifted and lowered together with the lift bracket 14 by the expansion and contraction of the lift cylinder 15. Drive wheels (front wheels) 16 are provided at the front lower portion of the vehicle body 11, and the drive wheels 16 are driven by a traveling motor 17 via a differential gear and gears (both not shown) mounted on the axle. . A fuel cell system 18 is mounted behind the vehicle body 11, and the fuel cell system 18 is covered with a hood 19. The fuel cell system 18 is used as a power source for a hydraulic motor (not shown) that serves as a hydraulic pressure source for the lift cylinder 15 and the tilt cylinder and a traveling motor 17.

Next, the fuel cell system 18 will be described with reference to FIG.
As shown in FIG. 2, the fuel cell system 18 includes a fuel cell 20, and a hydrogen tank 21 is connected to a hydrogen supply port (not shown) of the fuel cell 20 via a conduit 27. The fuel cell 20 is composed of, for example, a polymer electrolyte fuel cell. The fuel cell system 18 is provided with a compressor 22, and the compressor 22 is connected to the humidifier 23 via a pipe line 28. The humidifier 23 is connected to an oxygen supply port (not shown) of the fuel cell 20 via a supply pipe 29 and is connected to an off-gas discharge port (not shown) via a pipe 30. The air pressurized by the compressor 22 is humidified by the humidifier 23 and then supplied to the oxygen supply port (not shown) of the fuel cell 20 and from the cathode electrode (not shown) of the fuel cell 20. The off gas (cathode off gas) is discharged to the humidifier 23 via the pipe 30.

  The fuel cell 20 reacts hydrogen supplied from the hydrogen tank 21 with oxygen in the air supplied from the compressor 22 to generate DC electric energy (DC power). The conduit 27 is provided with a pressure regulating valve (not shown) that adjusts the pressure of hydrogen supplied to the fuel cell 20. The pressure regulating valve is a pressure control valve that reduces the hydrogen stored in the hydrogen tank 21 at a high pressure to a predetermined pressure and supplies the hydrogen at a constant pressure.

  The humidifier 23 is connected to the gas-liquid separator 24 via a discharge pipe 31, and a pressure regulating valve 32 is provided in the discharge pipe 31. Further, a hydrogen discharge port (not shown) of the fuel cell 20 is connected to the gas-liquid separator 24 via a purge gas conduit 33 as a hydrogen pipe, and from an anode electrode (not shown) of the fuel cell 20. The off gas (anode off gas) is discharged to the gas-liquid separator 24 through the purge gas pipe 33. The purge gas conduit 33 is provided with an on-off valve (anode purge valve) 34.

Next, the gas-liquid separator 24 will be described.
As shown in FIG. 3, the gas-liquid separator 24 is formed in a vertically long rectangular box shape. In the gas-liquid separator 24, the first chamber 41 and the second chamber 42 are partitioned by a partition plate 43. The partition plate 43 has a proximal end fixed to the side plate 24 a of the gas-liquid separator 24 and a first chamber 41 and a second chamber between the distal end of the partition plate 43 and the inner wall surface 24 b of the gas-liquid separator 24. 42 is provided in a state in which a gap 44 for communicating with 42 is formed.

  A discharge pipe 31 is connected to the side plate 24 a of the gas-liquid separator 24 so as to communicate with the inside of the first chamber 41. Further, a purge gas conduit 33 is connected to the side wall 24 d of the gas-liquid separator 24 so as to communicate with the inside of the second chamber 42. Further, a discharge pipe 46 is connected to the side plate 24 a of the gas-liquid separator 24 so as to communicate with the inside of the first chamber 41. A muffler 36 is provided in the middle of the discharge pipe 46.

  A first hole 48 is formed in the gas-liquid separator 24 so as to be separated from the flow of the cathode off-gas introduced from the exhaust line 31 (at a position removed), and the anode introduced from the purge gas line 33. A second hole 49 is formed so as to deviate from the flow of off-gas (at a position away from it).

  As shown in FIG. 4, a tank 50 is provided outside the gas-liquid separator 24. The tank 50 is attached to the outer surface of the gas-liquid separator 24, and the gas-liquid separator 24 and the tank 50 communicate with each other via a first hole 48 and a second hole 49. The first hole 48 and the second hole 49 are provided with a backflow prevention unit 51 so as to protrude into the tank 50.

  As shown in FIG. 5, a venturi portion 46 a is provided in the middle of the discharge pipe 46. The venturi portion 46a has a small-diameter portion 46b that is a portion where the conduit of the discharge pipe 46 is most narrowed, and a large-diameter portion 46c that expands from the small-diameter portion 46b toward the gas-liquid separator 24 side and the muffler 36 side. Have. Further, a through hole 46d is formed in the small diameter portion 46b. One end of an introduction pipe 50a for introducing water stored in the tank 50 into the discharge pipe 46 is connected to the tank 50, and the other end of the introduction pipe 50a is connected to a through hole 46d. The venturi portion 46a of the discharge pipe 46 and the tank 50 communicate with each other through the introduction pipe 50a.

Next, the operation of the fuel cell system 18 having the above configuration will be described.
In the fuel cell system 18, during operation of the fuel cell 20, hydrogen is supplied from the hydrogen tank 21 to the anode (hydrogen electrode) of the fuel cell 20 in a predetermined pressurized state. In addition, the compressor 22 is operated so that air is pressurized to a predetermined pressure and is humidified by the humidifier 23 to be supplied to the cathode (air electrode) of the fuel cell 20. Hydrogen supplied to the anode is dissociated into hydrogen ions and electrons by the catalyst, and the hydrogen ions move to the cathode together with water through the electrolyte membrane. At the cathode, oxygen in the air supplied to the cathode, hydrogen ions that move through the electrolyte membrane and reach the cathode, and electrons that have passed through the external circuit combine to generate water. When the pressure regulating valve 32 is opened, water generated at the cathode is discharged into the humidifier 23 as cathode offgas together with unreacted air in the form of water vapor, and the gas-liquid is discharged from the humidifier 23 via the discharge line 31. It is introduced into the first chamber 41 of the separator 24.

  In the gas-liquid separator 24, the cathode off-gas introduced into the first chamber 41 from the exhaust pipe 31 moves toward the front end side of the partition plate 43 while spreading against the partition plate 43 and enters the second chamber 42 from the gap 44. Inflow. Further, a part of the moisture contained in the cathode offgas adheres to the wall surface of the first chamber 41 and is separated from the cathode offgas, and then stored in the tank 50 through the first hole 48.

  Since a part of the cathode water and nitrogen reversely diffuses the electrolyte membrane from the cathode side to the anode side, the concentration of the anode water and nitrogen increases as the fuel cell 20 continues to operate. As a result, the power generation efficiency decreases. In order to prevent or suppress this, for example, when the fuel cell 20 continues to operate for a predetermined time, the on-off valve 34 is opened, and moisture and nitrogen accumulated in the anode are discharged together with hydrogen gas to the purge gas conduit 33. An anode purge is performed. The anode off-gas (purge gas) discharged from the fuel cell 20 to the purge gas conduit 33 by the anode purge is introduced into the second chamber 42 of the gas-liquid separator 24 through the purge gas conduit 33. Further, a part of the moisture contained in the anode off gas adheres to the wall surface of the second chamber 42 and is separated from the anode off gas, and is then stored in the tank 50 through the second hole 49.

  In the second chamber 42, the anode off gas is diluted with hydrogen concentration by the cathode off gas. Then, a mixed gas of cathode offgas and anode offgas, which is a gas from which water has been separated, is extruded into the first chamber 41 through the second hole 49, the tank 50, and the first hole 48, and is gas-liquid from the discharge pipe 46. It is discharged out of the separator 24. The anode off-gas introduced into the second chamber 42 from the purge gas conduit 33 and not discharged is diffused (expanded) throughout the second chamber 42 while expanding and diffusing while the anode is not purged. Thereafter, the anode off gas in the second chamber 42 moves to the first chamber 41, and also moves to the first chamber 41 via the tank 50 as a mixed gas of the cathode off gas and the anode off gas, along with the flow toward the discharge pipe 46. It is discharged out of the gas-liquid separator 24 from the discharge pipe 46.

  Since the venturi 46a is formed in the middle of the discharge pipe 46, the pressure of the small diameter part 46b in the discharge pipe 46 is higher than the pressure in the large diameter part 46c upstream and downstream of the small diameter part 46b. Lower. Therefore, the flow velocity of the mixed gas flowing into the discharge pipe 46 from the first chamber 41 of the gas-liquid separator 24 increases rapidly when passing through the small diameter portion 46b. Further, the pressure in the small diameter portion 46b is lower than the pressure in the tank 50, and a pressure difference is generated in the connection portion between the through hole 46d and the introduction pipe 50a, and is stored in the tank 50 due to the venturi effect. The sucked water is sucked up through the introduction pipe 50a and introduced into the small diameter part 46b through the through hole 46d. Then, in the small-diameter portion 46b, the sucked-up water is atomized by the mixed gas in a state where the flow velocity is rapidly increased to become atomized water, and this atomized water is discharged together with the mixed gas from the discharge port of the discharge pipe 46 through the muffler 36. Released to the atmosphere.

In the above embodiment, the following effects can be obtained.
(1) A venturi portion 46 a is provided in the middle of the discharge pipe 46 connected to the gas-liquid separator 24. The tank 50 and the venturi portion 46a are connected by an introduction pipe 50a. Therefore, the flow rate of the mixed gas discharged from the gas-liquid separator 24 increases rapidly when passing through the venturi portion 46a. In addition, due to the venturi effect, water stored in the tank 50 is sucked up through the introduction pipe 50 a and introduced into the venturi section 46 a of the discharge pipe 46. The sucked-up water is atomized by the mixed gas in a state where the flow velocity is rapidly increased in the small diameter portion 46 b of the venturi portion 46 a to become atomized water, and the atomized water is discharged to the atmosphere through the discharge pipe 46. Therefore, the water stored in the tank 50 can be atomized and discharged into the atmosphere as atomized water simply by providing the venturi 46a in the discharge pipe 46 without using a drain pump. As a result, it is possible to prevent the forklift 10 that travels or works using the fuel cell 20 as a driving source from dripping water indoors to wet the floor.

  (2) According to this embodiment, the water stored in the tank 50 can be atomized and discharged to the atmosphere without using a drain pump. Therefore, in order to atomize the water stored in the tank 50, for example, it is not necessary to pressurize the water with the drain pump, energy for driving the drain pump is not necessary, and energy consumption in the forklift 10 is reduced. Can do. Further, a space for installing the drainage pump is not necessary, and space can be saved in the forklift 10. Furthermore, in the present embodiment, since no movable parts such as a drain pump are required, there is no problem of durability that may occur due to the movable parts, and in addition, a drain pump is installed. The cost can be reduced.

  (3) The gas-liquid separator 24 is provided with a dilution function for diluting hydrogen contained in the anode off-gas. Therefore, when the anode purge is performed to prevent or suppress the power generation efficiency of the fuel cell 20 from being lowered, the anode off-gas is introduced into the gas-liquid separator 24 and is also removed by the gas-liquid separator 24 having a dilution function. Hydrogen contained in the anode off gas is diluted. Therefore, the configuration of the fuel cell system 18 can be made compact compared to a configuration in which a diluter for diluting hydrogen is separately provided.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to FIG. In the embodiment described below, the same reference numerals are given to the same components as those in the embodiment described above, and the overlapping description is omitted or simplified.

  As shown in FIG. 6, the fuel cell system 18 is arranged in the vicinity of the radiator 61 in the forklift 10 as a heat source. The radiator 61 includes a fan 61 a and wind generated by driving the fan 61 a passes through the radiator 61. A discharge port 46e of the discharge pipe 46 is disposed downstream of the radiator 61 in the wind flow direction (the direction of the arrow W shown in FIG. 6). Then, the atomized water discharged from the discharge port 46 e of the discharge pipe 46 is discharged downstream from the radiator 61. Therefore, the atomized water is heated by the heat of the radiator 61 and is vaporized.

Therefore, according to the present embodiment, in addition to the same effects as the effects (1) to (3) of the first embodiment, the following effects can be obtained.
(4) The discharge port 46 e of the discharge pipe 46 is disposed so as to be located downstream of the radiator 61. Therefore, the atomized water discharged from the discharge port 46e is heated and vaporized by the high-temperature heat generated from the radiator. Therefore, the atomized water discharged from the discharge pipe 46 can be vaporized by the radiator 61 and discharged to the atmosphere.

In addition, you may change the said embodiment as follows.
In the first embodiment, the gas-liquid separator 24 does not have the above-described dilution function, and for example, a diluter that can dilute the hydrogen concentration of the anode off-gas is provided in the middle of the purge gas conduit 33. Also good.

  In the second embodiment, the discharge port 46e of the discharge pipe 46 is disposed downstream of the radiator 61. However, the discharge port 46e of the discharge pipe 46 is upstream of the radiator 61, and the fan 61a and the radiator 61 You may arrange | position between. According to this, the water discharged toward the upstream side of the radiator 61 in the atomized state is sent to the wind generated from the fan 61a and passes through the radiator 61, and in this passage, the radiator 61 It is vaporized by the heat. For this reason, compared with the case where the discharge port 46e of the discharge pipe 46 is arrange | positioned downstream from the radiator 61, it is easy to vaporize atomized water. Further, since the atomized water passes through the radiator 61, the radiator 61 can be cooled by the atomized water. In this case, it is preferable to manufacture the radiator 61 from a material that is not easily corroded by water.

  Although the present invention is applied to the forklift 10 as an indoor industrial vehicle, the present invention is not limited to this. For example, a tow truck or a hand lifter as an indoor industrial vehicle (moving is performed by an operator pushing a lifter It is also possible to apply to an apparatus etc.

  The forklift 10 is not limited to indoor use but may be a forklift that performs work outdoors. Moreover, you may apply this invention to the industrial vehicle for outdoor work other than a forklift.

The present invention may be applied not only to industrial vehicles but also to other vehicles.
The present invention is not necessarily limited to a moving body such as a vehicle, and may be installed in an electrical product that requires a power source or may be applied to a stationary fuel cell system.

Next, the technical idea that can be grasped from the above embodiment and other examples will be described below.
(1) The fuel according to claim 3, wherein the atomized water discharged from the discharge pipe is discharged toward the upstream side of the radiator in the flow of wind generated toward the radiator. Battery system.

  DESCRIPTION OF SYMBOLS 10 ... Forklift as an indoor industrial vehicle, 18 ... Fuel cell system, 20 ... Fuel cell, 24 ... Gas-liquid separator, 33 ... Pipe for purge gas as hydrogen piping, 46 ... Discharge pipe, 46a ... Venturi section, 46e ... exhaust port, 50 ... tank, 50a ... introducing pipe, 61 ... radiator as heat source.

Claims (4)

A fuel cell;
A gas-liquid separator for separating water from off-gas discharged from the fuel cell;
A tank capable of storing water separated by the gas-liquid separator;
A discharge pipe for discharging the gas from which water has been separated by the gas-liquid separator from the gas-liquid separator and having a venturi section;
An introduction pipe for introducing water stored in the tank into the venturi section,
A fuel cell system, wherein water stored in the tank is atomized by being introduced into the venturi portion through the introduction pipe and is discharged from the discharge pipe as atomized water.   The gas-liquid separator is connected to a hydrogen pipe that guides the anode off-gas from the fuel cell to the gas-liquid separator, and the gas-liquid separator has a dilution function for diluting the hydrogen contained in the anode off-gas. The fuel cell system according to claim 1, comprising:   3. The fuel cell system according to claim 1, wherein a discharge port of the discharge pipe is provided at a position where the atomized water is vaporized by a heat source.   The fuel cell system according to any one of claims 1 to 3, wherein the fuel cell system is mounted on an indoor industrial vehicle.

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