JP2006080039A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system where reduction in the running cost necessary for preventing freezing and the prevention of damage to a device are made possible. <P>SOLUTION: The fuel cell system is provided with a water cycle system which comprises a water supply means 2 communicating with a fuel cell 1 and including a pipe 2a and a pump 2b to supply the fuel cell 1 with water, a water collection means 3 communicating with the fuel cell 1 and including a pipe 3a to collect water from the fuel cell 1, and a water tank 4 communicating with the fuel cell 1, the water supply means 2 and the water collection means 3 to cause water to flow backward; and a water-moving means which comprises an underground water tank 5 buried in the ground, a draining means 6 including a pipe 6a and an on-off valve 6b to drain the water in the water cycle system into the underground water tank 5, and a pumping means 7 including a pipe 7a and a pump 7b to pump the water stored in the underground water tank 5 into the water cycle system. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel cell system, and more particularly to a fuel cell system in which water freezing prevention means are improved.

  A fuel cell system supplies fuel such as hydrogen and an oxidant such as air to the fuel cell body and causes them to react electrochemically, thereby converting the chemical energy of the fuel directly into electrical energy and taking it out. However, since heat is generated in the process of this electrochemical reaction, the fuel cell system cools the fuel cell body by circulating water from the storage tank to the fuel cell body through the water supply / drainage pipe.

  Further, as a result of the electrochemical reaction of the fuel cell main body, hydrogen and oxygen are combined to produce water, and a part of this water is recovered in the storage water tank of the fuel cell system. Further, in the case of a polymer electrolyte fuel cell, water is supplied or circulated to the fuel cell body in order to wet the polymer ion exchange membrane of the fuel cell body.

  However, when the fuel cell system having such a configuration is stopped for a certain period of time in a sub-freezing environment, the water in the fuel cell system is frozen and the device is damaged due to freezing and expansion. There is a problem that it takes a lot of time and energy to melt ice.

  Solutions to these problems include installing an electric heater or burner combustor in the fuel cell system housing so that the temperature inside the housing does not drop below the freezing temperature, A method has been proposed in which water in the system is discharged to the outside and discarded, and water is newly supplied from the outside at the time of restart.

  However, heat retention by electric heater or burner combustion increases running costs such as electricity costs and fuel costs. In addition, since water used in fuel cell systems is generally ion-exchanged water with low electrical conductivity, the method of discharging water to the outside and disposing of it as a countermeasure against freezing requires a new one from the outside when restarting. Since it is necessary to replenish water, the cost of generating water bills and ion exchange water is generated, which is not preferable from the viewpoint of reducing the maintenance cost of the fuel cell system.

In order to solve these problems, Patent Document 1 provides a subtank for collecting water in the fuel cell system, collects water in the fuel cell system in the subtank after the operation is completed, and removes the subtank. Thus, a method of storing in a place where there is no risk of freezing has been proposed.
Japanese Patent No. 3416512

  However, as in the method according to Patent Document 1, in order to store water in a place where there is no risk of freezing, it is necessary for the operator of the fuel cell system to transport and move the sub-tank. In the absence of the operator, there was a problem that water freezing could not be avoided.

  The present invention has been proposed in order to solve the above-described problems of the prior art, and the object thereof is to reduce the running cost necessary for the countermeasure against freezing and reduce the equipment cost without requiring complicated work. An object of the present invention is to provide a fuel cell system capable of preventing damage.

  In order to achieve the above object, the invention described in claim 1 includes a water supply means for supplying water to the fuel cell body, a water recovery means for recovering water from the fuel cell, the water supply means, and the water In a fuel cell system having a water circulation system having a water tank through which water is circulated through a recovery means, the underground water tank installed in the ground, and the water circulation system and the underground water tank communicate with each other. It has the water movement means to move, It is characterized by the above-mentioned.

  In the invention according to claim 1 having the above-described configuration, the water in the water circulation system can be moved and stored in the underground water tank installed in the ground while the operation of the fuel cell system is stopped. Even when the surface temperature is below freezing, damage to the equipment due to freezing can be prevented. In addition, even when the operation is resumed, it can be used by being pumped from the underground water tank without being thawed.

  According to a second aspect of the present invention, in the fuel cell system according to the first aspect, the water tank is an underground water tank installed in the ground.

  In the invention according to claim 2 having the above-described configuration, the water tank itself can be installed in the ground so that the function of the underground water tank can be shared. Is done. In addition, since the water circulated and supplied to the fuel cell is always circulated to the underground water tank, it can be cooled in the ground even in the summer when the outside air temperature is high, so the heat exchanger provided in the water circulation system The load can be reduced.

  The invention according to claim 3 is the fuel cell system according to claim 1 or 2, wherein the underground water tank is installed at a depth at which moisture does not freeze in the ground. To do.

  In the invention according to claim 3 having the above-described configuration, since the water in the underground water tank does not freeze throughout the year, when the operation of the fuel cell system is resumed, the water is pumped from the underground water tank at any time. Thus, the operation can be resumed, so that the fuel cell system can be operated more economically.

  According to a fourth aspect of the present invention, in the fuel cell system according to any one of the first to third aspects, the temperature detecting means for detecting the water temperature in the water circulation system, and the temperature in the housing of the fuel cell system are determined. And at least one of a temperature detecting means for detecting and a temperature detecting means for detecting the temperature of the outside air, and the temperature detected by any of the temperature detecting means is a predetermined value set in advance for each temperature detecting means. When the value is lower than the value, water in the water circulation system is moved to the underground water tank.

  In the invention according to claim 4 having the above-described configuration, whether or not the water in the water circulation system can be moved to the underground water tank is detected by one or more temperature detection means installed at a predetermined site. Since water is discharged only when there is a possibility of freezing as determined by temperature, the number of water discharges and pumping operations can be reduced, and the running cost required for operation can be reduced.

  According to a fifth aspect of the present invention, in the fuel cell system according to any one of the first to fourth aspects, a heating unit is provided in at least one of the water moving unit or the water circulation system. Features.

  In the invention according to claim 5 having the above-described configuration, the heating means provided in at least one of the water moving means or the water circulation system prevents inconvenience due to freezing of the water, so a more reliable countermeasure against freezing is taken. Can be implemented.

  According to a sixth aspect of the present invention, in the fuel cell system according to the fifth aspect, the temperature detecting means for detecting the pipe temperature of the water moving means, the temperature detecting means for detecting the water temperature of the water circulation system, and the fuel cell It has at least one of a temperature detection means for detecting the temperature inside the system casing and a temperature detection means for detecting the temperature of the outside air, and the temperature detected by any one of the temperature detection means is previously set for each temperature detection means. When the temperature is lower than each predetermined value, water is heated by the heating means.

  In the invention according to claim 6 having the above-described configuration, the operation of the heating means provided in at least one of the water moving means or the water circulation system is performed by one or more temperature detecting means installed at a predetermined site. Since the heating means can be operated only when there is a possibility of freezing as determined by the detected temperature, a more reliable measure against freezing can be implemented.

  According to the present invention, it is possible to provide a fuel cell system capable of reducing running cost necessary for countermeasures against freezing and preventing damage to equipment without requiring complicated work.

  Next, the best mode for carrying out the present invention (hereinafter referred to as “embodiment”) will be specifically described with reference to the drawings.

(1) First Embodiment (1-1) Configuration As shown in FIG. 1, the fuel cell system of the present embodiment includes a fuel cell 1 including a fuel electrode and an oxidant electrode arranged with an electrolyte interposed therebetween, A fuel supply means (not shown) for supplying a fuel gas to the fuel cell 1, an oxidant gas supply means (not shown) for supplying an oxidant gas to the fuel cell 1, and a fuel gas and an oxidizer on the fuel electrode and the oxidant electrode of the fuel cell 1 A water supply means comprising an electric control device (not shown) for controlling the electromotive force generated by supplying the agent gas and taking out electric energy, and a pipe 2a connected to the fuel cell 1 and supplying water to the fuel cell 1 and a pump 2b. 2 is connected to the fuel cell 1, and is connected to the water recovery means 3 including a pipe 3 a for recovering water from the fuel cell 1, the fuel cell 1, the water supply means 2, and the water recovery means 3 to recirculate water. Water tank 4 And a ground water tank 5 buried in the ground, a drain 6 comprising a pipe 6a for discharging water from the water circulation system to the ground water tank 5 and an on-off valve 6b, and a ground water tank. 5 is constituted by a water moving means having a pipe 7a for pumping the water stored in the water circulation system and a pumping means 7 comprising a pump 7b.

  In addition, it is desirable that the installation depth of the underground water tank 5 in the ground is deeper than the depth from the ground surface where moisture in the ground is not frozen throughout the year.

(1-2) Operation Next, the flow of water before and after operation stop will be described for the fuel cell system of the present embodiment having the above-described configuration.

(1-2-1) During operation of the fuel cell system During the operation of the fuel cell system, the on-off valve 6b of the discharge means 6 is closed, and the water stored in the water tank 4 is supplied to the pump of the water supply means 2 2b is supplied to the fuel cell 1 through the pipe 2a, and the water from the fuel cell 1 is returned to the water tank 4 through the pipe 3a of the water recovery means 3.

(1-2-2) During Stop of Operation of Fuel Cell System Next, when the fuel cell system stops operating, the pump 2b of the water supply means 2 is stopped, and the on-off valve 6b of the discharge means 6 is opened, so that gravity As a result, the water staying in the fuel cell 1, the water tank 4, the water supply means 2, and the water recovery means 3 is discharged to the underground water tank 5 through the pipe 6 a of the discharge means 6.

(1-2-3) When resuming operation of the fuel cell system When resuming operation, the on-off valve 6b of the discharging means 6 is closed, the pump 7b of the pumping means 7 is operated, and the fuel cell system stays in the underground water tank 5. After the water which has been pumped up to the water tank 4 through the pipe 7a of the pumping means 7, the pump 2b of the water supply means 2 is operated, and the water circulation similar to that during the operation of the fuel cell system is resumed.

(1-3) Effect As described above, in the present embodiment, since the water in the water circulation system is stored in the underground water tank 5 buried in the ground while the operation of the fuel cell system is stopped, There is no water to be frozen in equipment other than the middle water tank 5, and the equipment will not be damaged by freezing even if it is not kept warm by a heater or the like.

  Even when the surface temperature is below freezing, the underground temperature is higher than the surface temperature, so the water in the underground water tank 5 is difficult to freeze and can be used without being thawed. Operation is possible. When the underground water tank 5 is installed at a position deeper than the depth from the ground surface where the underground water does not freeze throughout the year, the water in the underground water tank 5 does not freeze throughout the year, and the fuel cell When resuming the operation of the system, water can always be pumped from the underground water tank 5 and the operation can be resumed, so that the fuel cell system can be operated more economically.

(2) Configuration of the Second Embodiment (2-1) The fuel cell system of the present embodiment embeds the water tank 4 in the fuel cell system of the first embodiment in the ground, and the underground water tank of FIG. This is a combination of 5 functions.

  That is, in the fuel cell system of this embodiment, as shown in FIG. 2, the water supply means 2 including the pipe 2a for supplying water to the fuel cell 1 and the pump 2b is opened and closed with the pump 7b connected in parallel to each other. The pipe 3a of the water recovery means 3 that is connected to the underground water tank 5 buried in the ground through the pumping means 7 including the valve 7c and recovers water from the fuel cell 1 is directly connected to the underground water. It communicates with the tank 5. In addition, it is desirable that the installation depth of the underground water tank 5 in the ground is a position deeper than the depth from the ground surface where moisture in the ground is not frozen throughout the year.

(2-2) Operation Next, the flow of water before and after operation stop will be described for the fuel cell system of the present embodiment having the above-described configuration.

(2-2-1) During operation of the fuel cell system During operation of the fuel cell system, the water stored in the underground water tank 5 is caused by the action of the pump 2b of the water supply means 2 to the piping 2a and the pumping means 7. Is supplied to the fuel cell 1 through the open / close valve 7 c, and the water from the fuel cell 1 is returned to the underground water tank 5 through the pipe 3 a of the water recovery means 3.

(2-2-2) During stoppage of operation of the fuel cell system Next, when the operation of the fuel cell system stops, the pump 2b of the water supply means 2 is stopped, and the fuel cell 1 and the water supply means 2 are caused by the action of gravity. The water staying in the water recovery means 3 is stored in the underground water tank 5.

(2-2-3) When restarting operation When starting the operation, the on-off valve 7c of the pumping means 7 is closed, the pump 7b is operated, water is pumped up to the pump 2b of the water supply means 2, and then water is supplied. The pump 2b of the means 2 is operated, the on-off valve 7c of the pumping means 7 is opened, and water is returned to the underground water tank 5 through the pipe 3a of the fuel cell 1 and the water recovery means 3, so that the operation of the fuel cell system is performed. The circulation of water as in the inside resumes.

(2-3) Effects As described above, in the present embodiment, the water tank itself can be installed in the ground, and the functions of the underground water tank can be combined, so the number of components of the fuel cell system is reduced. be able to. In addition, during the shutdown of the fuel cell system, water in the water circulation system is stored in the underground water tank 5 buried in the ground, so that there is water to be frozen in devices other than the underground water tank 5. No equipment breakage due to freezing even without heat insulation with a heater or the like.

  Also, even when the surface temperature is below freezing, the underground temperature is higher than the surface temperature, so the water in the underground water tank 5 is difficult to freeze and can be used without being thawed. Operation is possible. Further, when the underground water tank 5 is installed at a position deeper than the depth from the ground surface where the underground water does not freeze throughout the year, the water in the underground water tank 5 does not freeze throughout the year, and the fuel cell system When the operation is resumed, the operation can be resumed by always pumping water from the underground water tank 5, so that more economical operation is possible.

  Further, in the present embodiment, the following effects can be obtained. That is, in a fuel cell system, a heat exchanger (not shown) for cooling water is usually provided in the water circulation system so as to cool the heated water discharged from the fuel cell 1. However, in this embodiment, since the water circulated and supplied to the fuel cell 1 is always circulated to the underground water tank 5, it is cooled in the ground even in the summer when the outside air temperature is high. Therefore, the load on the heat exchanger can be reduced.

(3) Configuration of Third Embodiment (3-1) The fuel cell system of the present embodiment is obtained by further improving the fuel cell system of the first embodiment.

  That is, in the fuel cell system of the present embodiment, as shown in FIG. 3, the water tank 4 is provided with the first temperature detection means 8 and the water level detection means 14, and the piping 6 a of the discharge means 6 is provided with A pump 6c, a second temperature detection means 10a, and a first antifreeze heater 9a which is a water heating means are provided. A pipe 7a of the pumping means 7 has a third temperature detection means 10b and water A second anti-freezing heater 9b, which is a heating means, and a first exhaust means 12 comprising a pipe 12a and an on-off valve 12b communicated with the underground water tank 5, and a pipe connected to the water tank 4 The 2nd exhaust means 13 which consists of 13a and the on-off valve 13b is connected. Since other configurations are the same as those of the first embodiment, description thereof will be omitted.

(3-2) Operation Next, the flow of water before and after operation stop will be described for the fuel cell system of the present embodiment having the above-described configuration.

(3-2-1) During operation of the fuel cell system During operation of the fuel cell system, the water stored in the water tank 4 is supplied to the fuel cell 1 via the pipe 2a by the action of the pump 2b of the water supply means 2. The water from the fuel cell 1 is returned to the water tank 4 through the pipe 3 a of the water recovery means 3.

(3-2-2) During Stop of Operation of Fuel Cell System Next, when the fuel cell system stops operating, the pump 2b of the water supply means 2 is stopped, and the fuel cell system is a first provided in the water tank 4. The temperature monitoring mode by the temperature detecting means 8 is set. In this temperature monitoring mode, when the temperature detected by the first temperature detecting means 8 becomes lower than a predetermined temperature set in advance so that the water in the water tank 4 does not freeze, the fuel cell system It becomes water discharge mode.

  In the water discharge mode, first, the temperature of the second temperature detection means 10a installed in the pipe 6a of the discharge means 6 is detected, and the detected temperature is set in advance so that the water being discharged does not freeze. When the temperature is lower than the first temperature, the first antifreeze heater 9a installed in the discharge means 6 operates, and the pipe 6a of the discharge means 6 is maintained at a temperature higher than a predetermined temperature.

  Next, the open / close valve 13b of the second exhaust means 13 installed in the water tank 4, the open / close valve 12b of the first exhaust means 12 installed in the underground water tank 5, and the open / close valve 6b of the discharge means 6 Is opened and the pump 6c of the discharge means 6 is operated, so that the water retained in the fuel cell 1, the water tank 4, the water supply means 2 and the water recovery means 3 is grounded through the pipe 6a of the discharge means 6. While being discharged into the middle water tank 5, air is introduced into the water tank 4 from the outside via the exhaust pipe 13 a, and the air remaining inside the underground water tank 5 is routed through the pipe 12 a of the exhaust means 12. Discharged outside.

  Here, as a transition condition from the temperature monitoring mode to the water discharge mode, the temperature detected by the first temperature detecting means 8 installed in the water tank 4 is lower than a predetermined value set in advance. In addition to this, the temperature detected by at least one of a water circulation system temperature detection means (not shown), an outside air temperature detection means (not shown), and a temperature detection means in the casing of the fuel cell system (not shown) is the water circulation system. If the water is lower than each predetermined value set in advance so as not to freeze, the water discharge mode may be shifted.

  Alternatively, the temperature detected by the temperature detecting means of the water circulation system is lower than a predetermined value set in advance, and at the same time, the temperature detected by at least one of the outside air temperature detecting means and the temperature detecting means in the housing of the fuel cell system However, the water discharge mode may be shifted only when the water in the water circulation system is lower than a predetermined value set in advance so as not to freeze.

  Further, when operating the first antifreeze heater 9a installed on the discharge means 6 in the water discharge mode, the second temperature detection means 10a installed on the pipe 6a of the discharge means 6 is not used and is not shown. The temperature detected by at least one of the temperature detection means of the water circulation system, the outside air temperature detection means (not shown), and the temperature detection means in the casing of the fuel cell system (not shown) is set in advance so that the water being discharged does not freeze. If the value is lower than the predetermined value, the first antifreeze heater 9a installed in the discharge means 6 may be operated for a certain period of time.

(3-2-3) When resuming operation of the fuel cell system Next, when the fuel cell system resumes operation, first, the temperature of the third temperature detecting means 10b installed in the pipe 7a of the pumping means 7 is increased. When the detected temperature is lower than a predetermined temperature set in advance so that the pumped water does not freeze, the second antifreeze heater 9b installed in the pumping means 7 operates and pumps up the pumped water. The pipe 7a of the means 7 is maintained at a temperature higher than a predetermined temperature.

  Next, the opening / closing valve 6b of the discharging means 6 is closed, and the opening / closing valve 13b of the second exhausting means 13 installed in the water tank 4 and the opening / closing of the first exhausting means 12 installed in the underground water tank 5 are opened. When the valve 12b is opened and the pump 7b of the pumping means 7 is operated, the water staying in the underground water tank 5 is pumped to the water tank 4 via the pipe 7a of the pumping means 7, and the underground water Air is introduced into the tank 5 from the outside through the pipe 12 a, and the air staying inside the water tank 4 is discharged to the outside through the pipe 13 a of the second exhaust means 13.

  Next, the pump 7b of the pumping means 7 is stopped after operating for a predetermined time, and the on-off valves 12b and 13b installed in the exhaust means 12 and 13 are also closed. Next, when the water level detected by the water level detection means 14 installed in the water tank 4 is lower than a predetermined value, the water supply means is supplied from the outside by a water supply means (not shown), and then the water supply means The pump 2b of No. 2 operates, and the water circulation similar to that during the operation of the fuel cell system is resumed.

  Here, when operating the second antifreeze heater 9b installed in the pumping means 7, the ground temperature not shown is not used without using the third temperature detecting means 10b installed in the pipe 7a of the pumping means 7. The temperature detected by at least one of the temperature detecting means of the tank 5, the outside air temperature detecting means (not shown), and the temperature detecting means in the casing of the fuel cell system (not shown) is set in advance so that the pumped water does not freeze. When it is lower than the predetermined value, the second antifreezing heater 9b installed in the pumping means 7 may be operated for a certain period of time.

(3-3) Effect As described above, in the present embodiment, an effect equivalent to that of the first embodiment can be obtained, and whether or not it is possible to shift to the water discharge mode is determined based on the temperature detected by the temperature detection means, and the possibility of freezing Since water is discharged only when there is water, the number of water discharge and pumping can be reduced, and the running cost required for operation can be reduced.

  Further, by providing the first and second exhaust means 12, 13, when the water in the water circulation system is drained to the underground water tank, the pressure in the tank of the water tank 4 decreases and the underground water tank 5 Since the increase in the pressure in the tank is prevented, the water is surely discharged, and the action of the pump 6c of the discharging means 6 allows the water to be discharged quickly and reliably, so that the water into the water circulation system can be discharged. Damage to equipment due to residue is prevented.

  In addition, the first freeze prevention heater 9a installed in the discharge means 6 prevents inconvenience due to freezing of the water being discharged, so that the countermeasure against freezing is surely implemented. Further, the operation of the second antifreeze heater 9b installed in the pumping means 7 prevents inconvenience due to freezing of the water being pumped, so that the operation is reliably restarted. Thus, according to the configuration of the present embodiment, the economical operation of the fuel cell system can be reliably performed.

(4) Fourth Embodiment (4-1) Configuration The fuel cell system of this embodiment is obtained by further improving the fuel cell system of the second embodiment.

That is, the fuel cell system of this embodiment, as shown in FIG.
In the pipe 2a of the water supply means 2, a fourth temperature detecting means 10c and a third antifreeze heater 9c which is a water heating means are installed. Since other configurations are the same as those of the second embodiment, description thereof is omitted.

(4-2) Operation Next, the flow of water before and after operation stop will be described for the fuel cell system of the present embodiment having the above-described configuration.

(4-2-1) During Operation and Stop of Fuel Cell System The flow of water during operation of the fuel cell system and after the fuel cell system has stopped operating is the same as in the second embodiment.

(4-2-2) When restarting the operation of the fuel cell system Next, when starting the operation, first, the temperature of the fourth temperature detection means 10c installed in the pipe 2a of the water supply means 2 is detected, When the detected temperature is lower than a predetermined temperature set in advance so that the pumped water does not freeze, the third antifreeze heater 9c installed in the pipe 2a of the water supply means 2 operates, The pipe 2a of the water supply means 2 is maintained at a temperature higher than a predetermined temperature.

  Thereafter, the opening / closing valve 7c of the pumping means 7 is closed, the pump 7b is operated, and after pumping water to the pump 2b of the water supply means 2, the pump 2b of the water supply means 2 is operated, and the opening / closing valve of the pumping means 7 is operated. 7c is opened, and water is returned to the underground water tank 5 through the pipe 2a of the water supply means 2, the fuel cell 1 and the pipe 3a of the water recovery means 3, and the same water as during the operation of the fuel cell system Circulation resumes.

  Here, when operating the third antifreeze heater 9c installed in the pipe 2a of the water supply means 2, without using the fourth temperature detection means 10c installed in the pipe 2a of the water supply means 2, The temperature detected by at least one of the temperature detection means of the underground water tank 5 (not shown), the outside air temperature detection means (not shown), and the temperature detection means in the casing of the fuel cell system (not shown) prevents the pumped water from freezing. When the temperature is lower than a predetermined value set in advance, the antifreezing heater 9c installed in the pipe 2a of the water supply means 2 may be operated for a certain period of time.

(4-3) Effect As described above, in this embodiment, an effect equivalent to that of the second embodiment is obtained, and the water being pumped up by the action of the third antifreeze heater 9c provided in the water supply means 2 is obtained. Inconvenience due to freezing is prevented, so that the operation is surely resumed.
Thus, according to the configuration of the present embodiment, the economical operation of the fuel cell system can be reliably performed.

(5) Configuration of the Fifth Embodiment (5-1) The fuel cell system of this embodiment is obtained by replacing the pump 2b of the water supply means 2 in the fuel cell system of the first embodiment with a self-priming pump 2c. It is.

  That is, as shown in FIG. 5, the fuel cell system of the present embodiment is connected to the fuel cell 1 and includes a pipe 2a that supplies water to the fuel cell 1, a self-priming pump 2c, and an on-off valve 2d. Water is connected to the supply means 2 and the fuel cell 1, and is connected to the water recovery means 3 including a pipe 3 a for recovering water from the fuel cell 1, and the fuel cell 1, the water supply means 2 and the water recovery means 3. Discharge means 6 comprising a water circulation system having a water tank 4 to be recirculated, an underground water tank 5 buried in the ground, a pipe 6a for discharging water from the water circulation system to the underground water tank 5, and an on-off valve 6b. And a water moving means having a pipe 7a for pumping water stored in the underground water tank 5 to the water circulation system and a pumping means 7 comprising an on-off valve 7d.

(5-2) Operation Next, the flow of water before and after operation stop will be described for the fuel cell system of the present embodiment having the above-described configuration.

(5-2-1) During the operation of the fuel cell system During the operation of the fuel cell system, the on-off valve 6b of the discharge means 6 and the on-off valve 7d of the pumping means 7 are closed, and the on-off valve 2d of the water supply means 2 is closed. The water stored in the water tank 4 is supplied to the fuel cell 1 via the pipe 2a by the action of the self-priming pump 2c of the water supply means 2, and the water from the fuel cell 1 is water. The water is returned to the water tank 4 through the pipe 3 a of the recovery means 3.

(5-2-2) Stopping operation of fuel cell system Next, when the fuel cell system stops operation, the self-priming pump 2c of the water supply means 2 is stopped, and the on-off valve 2d of the water supply means 2 and the discharge are discharged. By opening the on-off valve 6b of the means 6, the water retained in the fuel cell 1, the water tank 4, the water supply means 2, and the water recovery means 3 due to the action of gravity is passed through the pipe 6a of the discharge means 6. , Discharged into the underground water tank 5.

(5-2-3) When resuming operation of the fuel cell system When resuming operation, the on-off valve 2d of the water supply means 2 and the on-off valve 6b of the discharge means 6 are closed, and the on-off valve 7d of the pumping means 7 is opened, The self-priming pump 2c of the water supply means 2 is operated, and the water staying in the underground water tank 5 is pumped to the water circulation system via the pipe 7a of the pumping means 7. Thereafter, the open / close valve 2d of the water supply means 2 is opened, the open / close valve 7d of the pumping means 7 is closed, the self-priming pump 2c of the water supply means 2 is operated, and the self-priming pump 2c of the water supply means 2 is activated. The water circulation similar to that during the operation of the fuel cell system is resumed.

(5-3) Effects As described above, in this embodiment, the pump of the water supply means is a self-priming pump, so that the pump 7b of the pumping means 7 in FIG. 1 is not used and is equivalent to the first embodiment. Therefore, the manufacturing cost and the maintenance cost of the pump can be reduced, and the fuel cell system can be provided that can be economically operated without causing damage to the equipment due to freezing.

(6) Sixth Embodiment (6-1) Configuration The fuel cell system of this embodiment is obtained by replacing the pump 2b of the water supply means 2 in the fuel cell system of the second embodiment with a self-priming pump 2c. It is.

That is, the fuel cell system of this embodiment, as shown in FIG.
A water supply means 2, which is connected to the fuel cell 1 and includes a pipe 2 a for supplying water to the fuel cell 1 and a self-priming pump 2 c, communicates with the underground water tank 5 buried in the ground, and also the fuel cell. 1, a water recovery means 3 including a pipe 3 a for recovering water from the fuel cell 1 is connected to the underground water tank 5.

(6-2) Operation Next, the flow of water before and after operation stop will be described for the fuel cell system of the present embodiment having the above-described configuration.

(6-2-1) During operation of the fuel cell system During operation of the fuel cell system, the water stored in the underground water tank 5 passes through the pipe 2a by the action of the self-priming pump 2c of the water supply means 2. The water from the fuel cell 1 is returned to the underground water tank 5 via the pipe 3 a of the water recovery means 3.

(6-2-2) Stopping the operation of the fuel cell system Next, when the fuel cell system stops operating, the self-priming pump 2c of the water supply means 2 stops, and by the action of gravity, the fuel cell 1 and The water staying in the water supply means 2 and the water recovery means 3 is stored in the underground water tank 5 through the pipe 2a of the water supply means 2 and the pipe 3a of the water recovery means 3.

(6-2-3) When resuming the operation of the fuel cell system When the operation is started, the self-priming pump 2c of the water supply means 2 is operated, the water stored in the underground water tank 5 is sucked up, The water is returned to the underground water tank 5 through the pipe 2a of the supply means 2, the fuel cell 1 and the pipe 3a of the water recovery means 3, and the water circulation similar to that during the operation of the fuel cell system is resumed.

(6-3) Effects As described above, in this embodiment, the pump of the water supply means is a self-priming pump, so that the pump 7b of the pumping means 7 in FIG. 2 is not used and is equivalent to the second embodiment. Therefore, the manufacturing cost and the maintenance cost of the pump can be reduced, and the fuel cell system can be provided that can be economically operated without causing damage to the equipment due to freezing.

(7) Other Embodiments The present invention is not limited to the above-described embodiments, and it goes without saying that the present invention can also be applied to a polymer electrolyte fuel cell system.

The figure which shows the structure of 1st Embodiment of the fuel cell system which concerns on this invention. The figure which shows the structure of 2nd Embodiment of the fuel cell system which concerns on this invention. The figure which shows the structure of 3rd Embodiment of the fuel cell system which concerns on this invention. The figure which shows the structure of 4th Embodiment of the fuel cell system which concerns on this invention. The figure which shows the structure of 5th Embodiment of the fuel cell system which concerns on this invention. The figure which shows the structure of 6th Embodiment of the fuel cell system which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel cell 2 ... Water supply means 2a ... Pipe 2b ... Pump 2c ... Self-priming pump 2d ... On-off valve 3 ... Water recovery means 3a ... Pipe 4 ... Water tank 5 ... Underground water tank 6 ... Discharge means 6a ... Pipe 6b ... Open / close valve 6c ... Pump 7 ... Pumping means 7a ... Pipe 7b ... Pump 7c ... Open / close valve 7d ... Open / close valve 8 ... First temperature detecting means 9a ... First antifreeze heater 9b ... Second antifreeze heater 9c ... third antifreezing heater 10a ... second temperature detecting means 10b ... third temperature detecting means 10c ... fourth temperature detecting means 12 ... first exhaust means 12a ... pipe 12b ... open / close valve 13 ... second Exhaust means 13a ... pipe 13b ... open / close valve 14 ... water level detection means

Claims (6)

Water supply means for supplying water to the fuel cell main body, water recovery means for recovering water from the fuel cell, and a water circulation system having a water tank in which water is circulated through the water supply means and the water recovery means. In the fuel cell system,
A fuel cell system comprising: an underground water tank installed in the ground; and water moving means for moving water by communicating the water circulation system and the underground water tank.   The fuel cell system according to claim 1, wherein the water tank is an underground water tank installed in the ground.   The fuel cell system according to claim 1 or 2, wherein the underground water tank is installed at a depth at which moisture does not freeze in the ground. At least one of temperature detecting means for detecting the water temperature in the water circulation system, temperature detecting means for detecting the temperature in the housing of the fuel cell system, and temperature detecting means for detecting the temperature of the outside air;
When the temperature detected by any of the temperature detection means is lower than a predetermined value preset for each temperature detection means, the water in the water circulation system is moved to the underground water tank The fuel cell system according to any one of claims 1 to 3, wherein the fuel cell system is provided.   The fuel cell system according to any one of claims 1 to 4, wherein a heating unit is provided in at least one of the water transfer unit or the water circulation system. Temperature detecting means for detecting the pipe temperature of the water moving means, temperature detecting means for detecting the water temperature of the water circulation system, temperature detecting means for detecting the temperature in the fuel cell system housing, and temperature for detecting the temperature of the outside air Having at least one detection means;
When the temperature detected by any one of the temperature detection means is lower than a predetermined value set in advance for each temperature detection means, water is heated by the heating means. The fuel cell system according to claim 5.

Images