JP2011216339A - Fuel cell system, and stopping method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell system in which deterioration of utilization efficiency of fuel is suppressed while controlling deterioration of the electrodes of the fuel cell stack.SOLUTION: When stopping power generation by a fuel cell stack 3, in a state that introduction and discharge of an anode gas in the anode 31 and introduction and discharge of a cathode gas in the cathode 32 are cut off, the water level of an anode side water tank 7 is raised and the anode gas in the anode side water tank 7 is supplied to the anode 31 and the anode 31 is pressurized. At this time, hydrogen moves from the anode 31 which is in a pressurized state by the anode gas to the cathode 32 side, thereby, the cathode 32 side is also pressurized. Like this, since the anode 31 side and the cathode 32 side become in a pressurized state, diffusion of oxygen from the outside of the fuel cell stack 3 into the anode 31 side and the cathode 32 side is suppressed and deterioration of electrodes of the fuel cell stack 3 can be controlled.

Description

  The present invention relates to a fuel cell system and a stopping method thereof.

  A conventional fuel cell system supplies a hydrogen-containing gas containing hydrogen and air to a fuel cell stack, and generates power in the fuel cell stack. The battery stack includes an anode, an electrolyte, and a cathode. A hydrogen-containing gas is supplied to the anode and air is supplied to the cathode. An example of such a fuel cell system is described in Patent Document 1.

Japanese Patent Laid-Open No. 2005-71778

  By the way, in the conventional fuel cell system, for example, when the hydrogen-containing gas is supplied to the anode of the fuel cell stack, for example, when the fuel cell system is started up, the cathode electrode may be deteriorated if oxygen is present on the anode side. is there. Further, if oxygen is present also on the cathode side, the electrode catalyst on the cathode side may be deteriorated. In order to prevent these problems, in the fuel cell system described in Patent Document 1, hydrogen-containing gas or air remaining in the fuel cell stack when the fuel cell system is stopped is replaced with an inert gas. However, in order to prevent the electrode from deteriorating, it is necessary to continue to supply the raw material gas as an inert gas even when the fuel cell system is stopped.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel cell system and a method for stopping the fuel cell system that can suppress deterioration of fuel utilization efficiency while suppressing deterioration of electrodes of the fuel cell stack.

  The present invention provides a fuel cell stack comprising an anode and a cathode, a first introduction line for introducing anode gas into the anode, a first outlet line for extracting anode gas from the anode, and a first introduction line for introducing cathode gas into the cathode. 2 An introduction line, a second introduction line for deriving cathode gas from the cathode, an anode side water tank for storing water, and an upstream side of the anode side water tank in the first introduction line. A first control valve that adjusts the introduction amount of the anode gas, a second control valve that is disposed in the first lead-out line and adjusts the lead-out amount of the anode gas, and when the power generation by the fuel cell stack is stopped And a control unit for closing the first control valve and the second control valve and controlling the water level of the anode water tank to rise. To.

  The present invention provides a fuel cell stack comprising an anode and a cathode, a first introduction line for introducing anode gas into the anode, a first outlet line for extracting anode gas from the anode, and a first introduction line for introducing cathode gas into the cathode. 2 introduction line, a second lead-out line for deriving the cathode gas from the cathode, an anode-side water tank for storing water, which is disposed in the first lead-out line, and a first introduction line for introducing the anode gas A first control valve that adjusts the amount, a second control valve that is disposed downstream of the anode-side water tank in the first lead-out line, and that adjusts the lead-out amount of the anode gas, and when power generation by the fuel cell stack is stopped And a control unit for closing the first control valve and the second control valve and controlling the water level of the anode water tank to rise. To.

  In these inventions, when power generation by the fuel cell stack is stopped, the water level of the anode-side water tank rises in a state where the lead-in / out of the anode gas at the anode is blocked, and the anode in the anode-side water tank Gas is supplied to the anode and the anode is pressurized. At this time, hydrogen moves from the anode side pressurized by the anode gas to the cathode side. In this way, the anode side is in a pressurized state, and further hydrogen moves to the cathode side, so that diffusion of oxygen from the outside of the fuel cell stack into the anode and cathode is suppressed, and deterioration of the electrodes of the fuel cell stack is suppressed. be able to.

  In addition, since it is not necessary to continue the process of replacing the gas in the fuel cell stack with an inert gas (raw gas) when the fuel cell system is stopped, the fuel utilization efficiency is suppressed while suppressing electrode deterioration. Can be improved. In addition, since there is no need to replace the gas in the fuel cell stack with an inert gas, there is no need to separately provide a bypass line for supplying the inert gas to the cathode, etc., and the fuel cell system can be downsized. Can do.

  The upstream part of the anode side water tank in the first introduction line is connected at a position lower than the water level of the anode side water tank, and the downstream part of the anode side water tank in the first introduction line is connected to the water level of the anode side water tank. It is preferable to be connected at a high position.

  In this case, by raising the water level of the anode side water tank, the anode gas in the anode side water tank is introduced into the anode, and the anode is pressurized.

  In addition, it is preferable that anode-side water supply means for supplying water to the anode-side water tank is further provided, and the control unit controls the amount of water supplied to the anode-side water tank by the anode-side water supply means.

  In this case, by controlling the amount of water supplied to the anode-side water tank by the anode-side water supply means, the anode can be easily pressurized to a predetermined pressure value. It becomes easy to maintain.

  A third control valve disposed in the second introduction line for adjusting the amount of cathode gas introduced; a fourth control valve disposed in the second lead-out line for adjusting the amount of cathode gas derived; A cathode-side water tank that is disposed downstream of the third control valve in the introduction line or upstream of the fourth control valve in the second lead-out line is further provided, and the control unit generates power by the fuel cell stack. When stopping, it is preferable that the first control valve, the second control valve, the third control valve, and the fourth control valve are closed and the control is performed so as to raise the water level of the cathode-side water tank.

  In this case, when power generation by the fuel cell stack is stopped, the lead-in / out of the anode gas at the anode and the cathodic gas at the cathode are blocked. Thereby, an anode and a cathode can be pressurized efficiently.

  The upstream part of the cathode side water tank in the second introduction line is connected at a position lower than the water level of the cathode side water tank, and the downstream part of the cathode side water tank in the second introduction line is connected to the water level of the cathode side water tank. It is preferable to be connected at a high position.

  In this case, by raising the water level of the cathode side water tank, the cathode gas in the cathode side water tank is introduced to the cathode, and the cathode is pressurized.

  In addition, it is preferable that the apparatus further includes a cathode-side water supply unit that supplies water to the cathode-side water tank, and the control unit controls the amount of water supplied to the cathode-side water tank by the cathode-side water supply unit.

  In this case, the cathode can be easily pressurized to a predetermined pressure value by controlling the amount of water supplied to the cathode side water tank by the cathode side water supply means, and the state of the predetermined pressure value It becomes easy to maintain.

  Further, the current sweep unit for sweeping the current of the fuel cell stack and a voltage value detection unit for detecting the voltage value of the fuel cell stack are further provided, and the control unit, before raising the water level of the anode side water tank, It is preferable to control the current sweep unit so that the voltage value detected by the voltage value detection unit is equal to or lower than the reference voltage value.

  In this case, oxygen on the cathode side of the fuel cell stack is consumed by the current sweep, so that deterioration of the electrodes of the fuel cell stack can be suppressed.

  In addition, it is preferable to further include a reformer that reforms the raw fuel with the reforming catalyst and generates a reformed gas as the anode gas.

  In this case, the reformed gas generated by the reformer can be used as the anode gas. That is, since liquid fuel (kerosene or the like) can be used as a raw material for generating the anode gas, it is possible to increase the versatility of the types of raw materials used for generating the anode gas.

  The present invention provides a fuel cell stack including an anode and a cathode, a first introduction line for introducing anode gas to the anode, a first outlet line for extracting anode gas from the anode, and a cathode gas to the cathode. A second introduction line; a second introduction line for deriving cathode gas from the cathode; an anode-side water tank that is disposed in the first introduction line and stores water; and upstream of the anode-side water tank in the first introduction line. A first control valve that adjusts the introduction amount of the anode gas, a second control valve that is arranged in the first derivation line, and that adjusts the derivation amount of the anode gas, and is arranged in the second introduction line; A fuel cell system comprising: a third control valve that adjusts the amount of cathode gas introduced; and a fourth control valve that is disposed in the second derivation line and adjusts the amount of cathode gas derivated. A stop method, the first control valve, a second regulating valve, a third control valve and the fourth control valve closed, comprising the step of raising the water level in the anode water tank, characterized in that.

  The present invention provides a fuel cell stack comprising an anode and a cathode, a first introduction line for introducing anode gas into the anode, a first outlet line for extracting anode gas from the anode, and a first introduction line for introducing cathode gas into the cathode. 2 introduction line, a second lead-out line for deriving the cathode gas from the cathode, an anode-side water tank for storing water, which is disposed in the first lead-out line, and a first introduction line for introducing the anode gas A first control valve that adjusts the amount; a second control valve that is disposed downstream of the anode-side water tank in the first lead-out line; A fuel cell system comprising: a third control valve that adjusts a gas introduction amount; and a fourth control valve that is disposed in the second derivation line and adjusts the cathode gas derivation amount. A stop method, the first control valve, a second regulating valve, a third control valve and the fourth control valve closed, comprising the step of raising the water level in the anode water tank, characterized in that.

  In these inventions, when power generation by the fuel cell stack is stopped, the water level of the anode water tank rises in a state where the lead-in / out of the anode gas at the anode and the cathodic gas at the cathode are blocked. Then, the gas in the anode side water tank is supplied to the anode, and the anode is pressurized. At this time, since the hydrogen in the anode gas moves from the anode side pressurized by the anode gas to the cathode side, the cathode side is also pressurized. As described above, since the anode side and the cathode side are in a pressurized state, diffusion of oxygen from the outside of the fuel cell stack into the anode and the cathode is suppressed, and deterioration of the electrodes of the fuel cell stack can be suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the fall of the utilization efficiency of a fuel can be suppressed, suppressing deterioration of the electrode of a fuel cell stack.

1 is a schematic configuration diagram of an embodiment of a fuel cell system according to the present invention. It is a flowchart which shows the flow of the control processing which a control part performs.

  Hereinafter, preferred embodiments of a fuel cell system according to the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  First, the overall configuration of the fuel cell system according to the present embodiment will be described. FIG. 1 is a schematic configuration diagram of a fuel cell system 1. As shown in FIG. 1, the fuel cell system 1 includes a reformer 2 that generates an anode gas (reformed gas) containing hydrogen from a gaseous fuel or a liquid fuel, and an anode gas generated by the reformer 2. And a fuel cell stack 3 that generates electricity using the fuel cell stack 3. The fuel cell system 1 is used as, for example, a household power supply source, and kerosene is used as a liquid fuel from the viewpoint that it can be easily obtained and stored independently. Yes.

  The reformer 2 is for reforming liquid fuel to generate anode gas, and has a reformer 21 and a burner 22. The reformer 21 performs a steam reforming reaction of liquid fuel and steam with a reforming catalyst to generate an anode gas containing hydrogen. The burner 22 supplies the amount of heat necessary for the steam reforming reaction by heating the reforming catalyst of the reformer 21. Note that the liquid fuel supplied to the reformer 2 is desulfurized by a desulfurizer (not shown).

  The fuel cell stack 3 is configured by stacking a plurality of battery cells 30. The fuel cell stack 3 generates power using the anode gas obtained by the reformer 2 and outputs a direct current. The battery cell 30 includes an anode 31, a cathode 32, and an electrolyte (not shown) that is a solid polymer disposed between the anode 31 and the cathode 32, and introduces an anode gas into the anode 31, By introducing a cathode gas (for example, air) containing oxygen into the cathode 32, an electrochemical power generation reaction is performed in each battery cell 30. In FIG. 1, only one battery cell 30 among the battery cells 30 to be stacked is illustrated.

  The fuel cell system 1 also includes a second introduction line L12 through which the cathode gas introduced into the cathode 32 circulates, and a second lead-out line L11 through which the cathode gas derived from the cathode 32 circulates. The second introduction line L12 includes an electromagnetic valve B12 (third adjustment valve) that adjusts the amount of cathode gas introduced into the cathode 32, and cathode-side water that humidifies the cathode gas introduced from the second introduction line L12. A tank 8 (for example, a bubbler tank or the like) is provided. The second lead-out line L11 is provided with an electromagnetic valve B11 (fourth control valve) for adjusting the amount of cathode gas led out from the cathode 32. The cathode 32 is provided with a pressure gauge P2 for detecting the pressure value in the cathode 32. In addition, although this embodiment demonstrates the case where solenoid valve B12 is used as an example of a control valve, you may use valves (for example, motorized valves etc.) of mechanisms other than a solenoid valve. Similarly, solenoid valves B11, B21, and B22 to be described later are examples of control valves, and valves of other mechanisms may be used.

  The upstream line L12a of the second introduction line L12 is connected to the lower part of the cathode side water tank 8, and the downstream line L12b of the second introduction line L12 is connected to the upper part of the cathode side water tank 8. . Moreover, the cathode side water tank 8 has water inside, and the water level is maintained between the opening of the line L12a connected to the cathode side water tank 8 and the opening of the line L12b. The cathode side water tank 8 humidifies the cathode gas introduced from the line L12a by passing it through the water contained therein. The humidified cathode gas is supplied to the cathode 32 through the line L12b.

  Further, the fuel cell system 1 includes a first introduction line L22 through which the anode gas introduced into the anode 31 is circulated, and a first derivation line L21 through which the anode gas derived from the anode 31 is circulated. The upstream side of the first introduction line L22 is connected to the reformer 21, and the anode gas generated by the reformer 21 is introduced to the anode 31 through the first introduction line L22. The first introduction line L22 includes an electromagnetic valve B22 (first adjustment valve) that adjusts the amount of anode gas introduced into the anode 31, and anode-side water that humidifies the anode gas introduced from the first introduction line L22. A tank 7 (for example, a bubbler tank or the like) is provided. Further, the first lead-out line L21 discharges anode gas (so-called off-gas) containing hydrogen that has not contributed to power generation in the fuel cell stack 3 among the anode gas supplied to the anode 31 through the first introduction line L22. Is for. The downstream side of the first lead-out line L21 is connected to the burner 22, and anode gas can be used as fuel for the burner 22. The first lead-out line L21 is provided with an electromagnetic valve B21 (second control valve) that adjusts the lead-out amount of the anode gas led out from the anode 31. The anode 31 is provided with a pressure gauge P1 that detects the pressure value in the anode 31.

  The upstream line L22a of the first introduction line L22 is connected to the lower part of the anode side water tank 7, and the downstream line L22b of the first introduction line L22 is connected to the upper part of the anode side water tank 7. . The anode side water tank 7 has water inside, and the water level is maintained between the opening of the line L22a connected to the anode side water tank 7 and the opening of the line L22b. The anode water tank 7 humidifies the anode gas introduced from the line L22a by passing it through the water contained therein. The humidified anode gas is supplied to the anode 31 through the line L22b.

  Further, the fuel cell system 1 includes a water supply line WL1 connected to a water source supplied to the anode side water tank 7 and the cathode side water tank 8, and the anode side water tank 7 and the cathode side water via the water supply line WL1. A pump WP1 (anode-side water supply means, cathode-side water supply means) for introducing water into the tank 8 is provided. The water supply line WL1 branches into a water supply line WL2 through which water supplied to the cathode side water tank 8 flows and a water supply line WL3 through which water supplied to the anode side water tank 7 flows. The water supply line WL2 is provided with an electromagnetic valve WB2 that adjusts the amount of water supplied to the cathode-side water tank 8. The water supply line WL3 is provided with an electromagnetic valve WB3 that adjusts the amount of water supplied to the anode-side water tank 7.

  The fuel cell system 1 includes a current sweep unit 5 that sweeps the current of the fuel cell stack 3 and a voltage value detection unit 6 that detects the voltage value of the fuel cell stack 3. Further, the fuel cell system 1 includes a control unit 4 that controls the electromagnetic valves B11, B12, B21, B22, WB2, WB3, the pump WP1, and the current sweep unit 5. The voltage value of the fuel cell stack 3 detected by the voltage value detection unit 6 is input to the control unit 4. Further, the pressure values detected by the pressure gauges P 1 and P 2 are input to the control unit 4.

  Next, the control of each unit performed by the control unit 4 when the power generation by the fuel cell stack 3 is stopped will be described. The execution of this control is started by operating a stop switch (not shown), for example. Further, in a state where power generation is performed by the fuel cell stack 3, the solenoid valves B11 and B12 are controlled to be in an open state (a state in which the cathode gas can flow through the second lead-out line L11 and the second introduction line L12). Yes. Further, the solenoid valves B21 and B22 are controlled to be in an open state (a state in which the anode gas can flow through the first lead-out line L21 and the first introduction line L22), and the anode gas is introduced from the reformer 2 into the anode 31. Yes. FIG. 2 is a flowchart showing a control processing procedure executed by the control unit 4.

  In step S101, the control unit 4 opens, for example, a drain valve (not shown) for draining water in the anode side water tank 7 and the cathode side water tank 8 to open the anode side water tank 7 and The water level in the cathode side water tank 8 is lowered.

  In step S102, the control unit 4 controls the solenoid valve B11 to shut off the cathode gas flow in the second lead-out line L11.

  In step S <b> 103, the control unit 4 controls the current sweep unit 5 to sweep the current of the fuel cell stack 3. Thereby, oxygen is consumed on the cathode 32 side and the oxygen concentration is lowered. Moreover, since hydrogen moves from the anode 31 side to the cathode 32 side, the hydrogen concentration on the cathode 32 side increases.

  By sweeping the current of the fuel cell stack 3 in step S103, oxygen on the cathode 32 side is consumed, the oxygen concentration is lowered, and the voltage value of the fuel cell stack 3 is lowered. Therefore, in step S104, the control unit 4 detects a decreasing voltage value by the voltage value detection unit 6, and determines whether or not the detected voltage value is equal to or less than a predetermined reference voltage value. If the voltage value is not less than or equal to the predetermined reference voltage value (step S104: NO), the processes in steps S103 and S104 are repeated until the voltage value becomes equal to or less than the predetermined reference voltage value. When it is determined that the voltage value is equal to or lower than the predetermined reference voltage value (step S104: YES), the process proceeds to step S105.

  In step S <b> 105, the control unit 4 controls the current sweep unit 5 to stop the current sweep of the fuel cell stack 3. In step S106, the control unit 4 controls the electromagnetic valve B12 to cut off the flow of the cathode gas in the second introduction line L12, controls the electromagnetic valve B21 to cut off the flow of the anode gas in the first lead-out line L21, Further, the solenoid valve B22 is controlled to interrupt the flow of the anode gas in the first introduction line L22.

  In step S107, the control unit 4 controls the pump WP1, and further controls the electromagnetic valve WB3 so that the pressure value detected by the pressure gauge P1 becomes a predetermined pressure value, thereby supplying water into the anode-side water tank 7. By supplying the water level, the anode 31 is pressurized. By pressurizing the anode 31, hydrogen actively moves from the anode 31 side to the cathode 32 side, thereby increasing the pressure value in the cathode 32. In this way, the pressure value in the cathode 32 increases as the pressure value in the anode 31 increases following the movement of hydrogen. By making the pressure value of the anode 31 detected by the pressure gauge P1 equal to the pressure value of the cathode 32 detected by the pressure gauge P2, the pressure balance to the electrolyte membrane becomes equal, which is preferable.

  In step S108, the control unit 4 determines whether the pressure value detected by the pressure gauge P1 or the pressure gauge P2 is equal to or lower than a predetermined reference pressure value (whether the detected pressure value has decreased to a predetermined reference pressure value). ). If the pressure value is not less than or equal to the predetermined reference pressure value (step S108: NO), the process of step S108 is repeated. On the other hand, when the pressure value is equal to or lower than the predetermined reference pressure value (step S108: YES), in step S109, the control unit 4 causes the anode side water tank 7 and the cathode side so that the pressure value becomes the predetermined reference pressure value. The water level of the water tank 8 is controlled. For example, when the pressure value detected by the pressure gauge P1 decreases (pressure value decrease on the anode 31 side), the control unit 4 controls the electromagnetic valve WB3 to increase the water level of the anode-side water tank 7 so that the anode 31 is moved. Pressurize. Further, for example, when the pressure value detected by the pressure gauge P2 decreases (pressure value decrease on the cathode 32 side), the control unit 4 controls the electromagnetic valve WB2 to increase the water level in the cathode side water tank 8. The cathode 32 is pressurized by controlling the electromagnetic valve WB3 to raise the water level of the anode-side water tank 7 or by raising the water levels of both the anode-side water tank 7 and the cathode-side water tank 8. For example, when both of the pressure values detected by the pressure gauges P1 and P2 are lowered, one or both of the electromagnetic valves WB2 and WB3 are controlled to control one or both of the anode-side water tank 7 and the cathode-side water tank 8. The anodes 31 and 32 are pressurized by raising the water level. By the processing in steps S108 and S109, the pressure values in the anode 31 and the cathode 32 are maintained at predetermined reference pressure values. Note that the processes of steps S108 and S109 are repeated until the power generation of the fuel cell stack 3 is resumed.

  Then, the effect | action and effect of the fuel cell system 1 which concern on this embodiment are demonstrated. According to the fuel cell system 1 of the present embodiment, when power generation by the fuel cell stack 3 is stopped, the anode side lead-in / out at the anode 31 and the cathode gas lead-in / out at the cathode 32 are blocked. The water level in the water tank 7 rises, the anode gas in the anode-side water tank 7 is supplied to the anode 31, and the anode 31 is pressurized. At this time, hydrogen moves from the anode 31 side that has been pressurized by the anode gas to the cathode 32 side, so the cathode 32 side is also in the pressurized state. Thus, since the anode 31 side and the cathode 32 side are in a pressurized state, diffusion of oxygen from the outside of the fuel cell stack 3 into the anode 31 and the cathode 32 is suppressed, and deterioration of the electrodes of the fuel cell stack 3 is suppressed. can do.

  In addition, it is not necessary to continue the process of replacing the gas in the fuel cell stack 3 with an inert gas (raw material gas) when the fuel cell system 1 is stopped. Use efficiency can be improved. Further, since it is not necessary to replace the gas in the fuel cell stack 3 with an inert gas, there is no need to separately provide a bypass line for supplying the inert gas to the cathode or the like, and the fuel cell system can be downsized. be able to.

  Further, the anode-side water tank 7 for humidifying the anode gas during the operation of the fuel cell stack 3 and the cathode-side water tank 8 for humidifying the cathode gas are used to add the anode 31 and the cathode 32 when the fuel cell stack 3 is stopped. By performing the pressure, it is not necessary to separately provide a new device for pressurizing the anode 31 and the cathode 32.

  Further, the anode 31 and the cathode 32 can be easily pressurized to predetermined pressure values only by controlling the amount of water supplied from the pump WP1 into the anode-side water tank 7 and the cathode-side water tank 8. Moreover, it becomes easy to maintain the state of a predetermined pressure value.

  In addition, the anode 31 is pressurized by the anode gas, and hydrogen moves from the anode 31 side to the cathode 32 side and into the cathode side water tank 8. Furthermore, the cathode 32 and the cathode side water tank 8 are pressurized by the rise of the water level of the cathode side water tank 8. Thereby, the anode 31 and the cathode 32 can be efficiently pressurized.

  In addition, by sweeping the current by the current sweep unit 5 until the voltage value of the fuel cell stack 3 reaches a predetermined voltage value, the voltage value of the fuel cell stack 3 can be efficiently reduced.

  Further, by providing the reformer 2, the reformer 2 can generate an anode gas containing hydrogen. That is, since liquid fuel (kerosene or the like) can be used as a raw material for generating the anode gas, it is possible to increase the versatility of the types of raw materials used for generating the anode gas.

  The present invention is not limited to the above embodiment. For example, without providing the solenoid valves B11 and B12 in the second lead-out line L11 and the second lead-in line L12, respectively, after controlling the solenoid valves B21 and B22 to shut off the first lead-out line L21 and the first lead-in line L22, The anode 31 may be pressurized by the anode water tank 7. Also in this case, the movement of hydrogen from the anode 31 to the cathode 32 suppresses the diffusion of oxygen into the cathode 32, thereby suppressing the deterioration of the electrodes of the fuel cell stack 3.

  Further, for example, in step S106, the gas flow in the three lines is cut off. First, the electromagnetic valve B21 is controlled to cut off the flow of the anode gas in the first lead-out line L21. One of the valves B11 and B12 is controlled to shut off one of the second lead-out line L11 and the second introduction line L12, and the anode 31 is pressurized for a predetermined time by the anode gas introduced from the first introduction line L22. And after pushing out the oxygen which remain | survives in the cathode 32 and the cathode side water tank 8 with the hydrogen which moved to the cathode 32, the other of solenoid valve B11, B12 is controlled, and the 2nd derivation | leading-out line L11 and the 2nd introduction line L12 are controlled. The other can be shut off, and further, the solenoid valve B22 can be controlled to shut off the circulation of the anode gas in the first introduction line L22. In the above example, the anode 31 is pressurized with the anode gas introduced from the first introduction line L22 for a predetermined time, but other than this, for example, the voltage value detected by the voltage value detection unit 6 is It is possible to pressurize the anode 31 until the voltage decreases to a predetermined voltage value, or pressurize the anode 31 until the pressure value detected by the pressure gauge P2 reaches a predetermined pressure value.

  As another modification, first, the solenoid valve B21 and the solenoid valve B22 are controlled to interrupt the circulation of the anode gas in the first lead-out line L21 and the first introduction line L22. The anode 31 is pressurized by raising the water level. And after pushing out the oxygen which remains in the cathode 32 and the cathode side water tank 8 with the hydrogen which moved to the cathode 32, solenoid valve B11 and solenoid valve B12 are controlled, and 2nd derivation | leading-out line L11 and 2nd introduction line L12 are made. It can also be blocked.

  It is also possible to pressurize the anode 31 and the cathode 32 only by controlling the water level of the anode side water tank 7 without pressurizing the cathode 32 by controlling the water level of the cathode side water tank 8. Further, the anode-side water tank 7 can be provided in each of the first lead-out line L21 and the first lead-in line L22, or the cathode-side water tank 8 can be provided in each of the second lead-out line L11 and the second lead-in line L12. . Further, when pure hydrogen is supplied to the anode 31 of the fuel cell stack 3 from a gas tank or the like, the reformer 2 may not be provided.

  DESCRIPTION OF SYMBOLS 1 ... Fuel cell system, 2 ... Reformer, 3 ... Fuel cell stack, 4 ... Control part, 5 ... Current sweep part, 6 ... Voltage value detection part, 7 ... Anode side water tank, 8 ... Cathode side water tank, 21 ... reformer, 31 ... anode, 32 ... cathode, B11, B12, B21, B22, WB2, WB3 ... solenoid valve, L11 ... second derivation line, L12 ... second introduction line, L21 ... first derivation line, L22 ... 1st introduction line, WL1 ... Water supply line, WP1 ... Pump.

Claims (11)

A fuel cell stack comprising an anode and a cathode;
A first introduction line for introducing an anode gas into the anode;
A first derivation line for deriving anode gas from the anode;
A second introduction line for introducing a cathode gas into the cathode;
A second derivation line for deriving cathode gas from the cathode;
An anode water tank disposed in the first introduction line and storing water;
A first control valve that is disposed upstream of the anode-side water tank in the first introduction line and adjusts the amount of anode gas introduced;
A second control valve disposed in the first derivation line for adjusting the derivation amount of the anode gas;
A control unit that closes the first control valve and the second control valve and controls to raise the water level of the anode-side water tank when power generation by the fuel cell stack is stopped. A fuel cell system is characterized. A fuel cell stack comprising an anode and a cathode;
A first introduction line for introducing an anode gas into the anode;
A first derivation line for deriving anode gas from the anode;
A second introduction line for introducing a cathode gas into the cathode;
A second derivation line for deriving cathode gas from the cathode;
An anode water tank disposed in the first lead-out line and storing water;
A first control valve that is disposed in the first introduction line and adjusts the amount of anode gas introduced;
A second control valve that is arranged downstream of the anode-side water tank in the first lead-out line and adjusts the lead-out amount of the anode gas;
A control unit that closes the first control valve and the second control valve and controls to raise the water level of the anode-side water tank when power generation by the fuel cell stack is stopped. A fuel cell system is characterized.   The upstream part of the anode side water tank in the first introduction line is connected at a position lower than the water level of the anode side water tank, and the downstream part of the anode side water tank in the first introduction line is connected to the anode side water tank. The fuel cell system according to claim 1, wherein the fuel cell system is connected at a position higher than the water level. An anode-side water supply means for supplying water to the anode-side water tank;
4. The fuel cell system according to claim 1, wherein the control unit controls an amount of water supplied to the anode-side water tank by the anode-side water supply unit. 5. A third control valve disposed in the second introduction line for adjusting the amount of cathode gas introduced;
A fourth control valve disposed in the second derivation line for adjusting the derivation amount of the cathode gas;
A cathode-side water tank that is disposed downstream of the third control valve in the second introduction line or upstream of the fourth control valve in the second lead-out line, and stores water;
The control unit closes the first control valve, the second control valve, the third control valve, and the fourth control valve when stopping power generation by the fuel cell stack, and the cathode-side water tank. 5. The fuel cell system according to claim 1, wherein the fuel cell system is controlled to raise the water level of the fuel cell.   The upstream part of the cathode side water tank in the second introduction line is connected at a position lower than the water level of the cathode side water tank, and the downstream part of the cathode side water tank in the second introduction line is connected to the cathode side water tank. The fuel cell system according to claim 5, wherein the fuel cell system is connected at a position higher than the water level. A cathode-side water supply means for supplying water to the cathode-side water tank;
The fuel cell system according to claim 5 or 6, wherein the control unit controls the amount of water supplied to the cathode-side water tank by the cathode-side water supply means. A current sweep unit that sweeps the current of the fuel cell stack; and a voltage value detection unit that detects a voltage value of the fuel cell stack,
The control unit controls the current sweep unit so that a voltage value detected by the voltage value detection unit is equal to or lower than a reference voltage value before raising the water level of the anode-side water tank. The fuel cell system according to any one of claims 1 to 7.   The fuel cell system according to any one of claims 1 to 8, further comprising a reforming device that reforms raw fuel with a reforming catalyst and generates a reformed gas as the anode gas. A fuel cell stack including an anode and a cathode; a first introduction line for introducing anode gas into the anode; a first outlet line for extracting anode gas from the anode; and a second introduction line for introducing cathode gas into the cathode. An introduction line; a second lead-out line that leads out cathode gas from the cathode; an anode-side water tank that is disposed in the first introduction line and stores water; and the anode-side water tank in the first introduction line A first control valve that is arranged upstream and adjusts the introduction amount of the anode gas; a second control valve that is arranged in the first lead-out line and adjusts the lead-out amount of the anode gas; and A third control valve that adjusts the amount of cathode gas introduced, and a fourth control valve that adjusts the amount of cathode gas delivered to the second derivation line. A method of stopping a fuel cell system comprising,
A method for stopping a fuel cell system, comprising: closing the first control valve, the second control valve, the third control valve, and the fourth control valve to raise the water level of the anode water tank. A fuel cell stack including an anode and a cathode; a first introduction line for introducing anode gas into the anode; a first outlet line for extracting anode gas from the anode; and a second introduction line for introducing cathode gas into the cathode. An introduction line; a second lead-out line for deriving cathode gas from the cathode; an anode-side water tank that is disposed in the first lead-out line and stores water; A first control valve that adjusts the amount of gas introduced, a second control valve that is arranged downstream of the anode-side water tank in the first lead-out line, and that adjusts the amount of lead-out of the anode gas; and the second lead-in line A third control valve that adjusts the amount of cathode gas introduced, and a fourth control valve that adjusts the amount of cathode gas delivered to the second derivation line. A method of stopping a fuel cell system comprising,
A method for stopping a fuel cell system, comprising: closing the first control valve, the second control valve, the third control valve, and the fourth control valve to raise the water level of the anode water tank.

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