JP2010108757A - Fuel cell system and method for stopping fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system capable of reliably starting the operation of a fuel cell system at zero temperature or lower, and to provide the scavenging method of the fuel cell system. <P>SOLUTION: The fuel cell system 10 including a fuel cell 11, reactant gas piping 38 through which reactant gas exhausted from the fuel cell flows, and a reactant gas-adjusting means 34 arranged onto the reactant gas piping and adjusting the flow of reactant gas, further includes a temperature detecting means 55 detecting the temperature of the reactant gas-adjusting means, a scavenging means 33 removing the produced water of the fuel cell attached to the reactant gas-adjusting means during stop of the power generation of the fuel cell, and a freezing determination means determining whether the produced water is freezed or not in the reactant gas-adjusting means based on the detected value of the temperature detecting means, wherein when the freezing determination means determines that the produced water may freeze in the reactant gas-adjusting means, the fuel cell system scavenges with the scavenging means. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  Conventionally, for example, in a fuel cell mounted on a vehicle, a membrane electrode structure is formed by sandwiching a solid polymer electrolyte membrane between an anode electrode and a cathode electrode from both sides, and a pair of separators are provided on both sides of the membrane electrode structure. A flat unit fuel cell (hereinafter referred to as a unit cell) is arranged to form a fuel cell stack (hereinafter referred to as a fuel cell) by stacking a plurality of unit cells. In such a fuel cell, hydrogen gas is supplied as an anode gas (fuel gas) between the anode electrode and the separator, and air is supplied as a cathode gas (oxidant gas) between the cathode electrode and the separator. As a result, hydrogen ions generated by the catalytic reaction at the anode electrode pass through the solid polymer electrolyte membrane and move to the cathode electrode, causing an electrochemical reaction with oxygen in the air at the cathode electrode, thereby generating power. It should be noted that water is generated inside the fuel cell with this power generation.

In a fuel cell system equipped with such a fuel cell, for example, when used in a sub-freezing environment, the generated water remaining inside is frozen while the fuel cell system is stopped. A technique for prohibiting activation of a fuel cell system is disclosed (for example, see Patent Document 1).
In the fuel cell system of Patent Document 1, when a start operation of the fuel cell system is performed, the shut valve is opened and the temperature is measured by a temperature sensor. If the measured temperature is less than the predetermined value, the pressure sensor determines whether the pressure value is normal. If it is normal, the discharge valve is opened and the pressure drop measured by the pressure sensor is normal. It is determined whether or not. Next, the discharge valve is closed, and it is determined whether or not the amount of pressure increase measured by the pressure sensor is normal. Next, the hydrogen pump is started and it is determined whether the rotation speed is normal. Next, the compressor is operated, and it is determined whether or not the pressure value measured by the pressure sensor is normal. In the above determination, if there is any abnormality, it is determined that there are frozen parts, and the activation of the fuel cell system is prohibited.
JP 2008-204957 A

By the way, in the fuel cell system of Patent Document 1, the start of the fuel cell system is prohibited when there are frozen parts as described above. However, even in such a sub-freezing environment, the fuel cell system is A technique that can be used is desired.
Further, in the fuel cell system, the generated water remaining inside the fuel cell system is frozen while the fuel cell system is stopped, so that water droplets adhering to the fuel cell system are removed so that the generated water does not freeze (scavenging). A method is disclosed. However, since the conventional scavenging method for a fuel cell system determines whether or not scavenging is performed according to the temperature of the fuel cell, for example, the fuel cell is warmed up by starting the fuel cell system for a short time. However, scavenging is not performed when the valves are not warmed up. For this reason, the generated water adheres to the valves and freezes, and there is a possibility that the fuel cell system cannot be normally started when the fuel cell system is next started.

  Accordingly, the present invention has been made in view of the above circumstances, and provides a fuel cell system and a scavenging method for the fuel cell system that can reliably start the fuel cell system in a sub-freezing environment.

  In order to solve the above problems, the invention described in claim 1 is a fuel cell (for example, fuel cell 11 in the embodiment) that generates electricity by supplying an anode gas to an anode electrode and a cathode gas to a cathode electrode; A reaction gas pipe (for example, the cathode offgas discharge pipe 38 in the embodiment) through which the reaction gas discharged from the fuel cell flows, and a reaction gas adjusting means that is arranged in the reaction gas pipe and adjusts the flow of the reaction gas ( For example, a fuel cell system (for example, the fuel cell system 10 in the embodiment) including the back pressure valve 34 in the embodiment, and a temperature detection unit (for example, the embodiment) that detects the temperature of the reaction gas adjusting unit. The temperature sensor 55) of the fuel cell, and removal of water produced by the fuel cell adhering to the reaction gas adjusting means during the power generation stop of the fuel cell. A scavenging means (for example, the air compressor 33 in the embodiment) and a freezing determining means (for example, determining whether or not the generated water is frozen in the reaction gas adjusting means based on the detection value of the temperature detecting means) A back pressure valve freezing determination unit 48) according to the embodiment, and when the freezing determination unit determines that the generated water may be frozen by the reaction gas adjustment unit, scavenging by the scavenging unit is performed. It is configured to be executable.

  The invention described in claim 2 includes a generated water amount detecting means (for example, a generated water amount detecting unit 47 in the embodiment) for detecting the generated water amount generated in the fuel cell during power generation of the fuel cell, When the amount of generated water is less than or equal to a predetermined amount, scavenging of the reaction gas adjusting means is not executed.

  The invention described in claim 3 includes fuel cell internal freezing determination means (for example, the fuel cell internal freezing determination unit 50 in the embodiment) for determining whether or not the generated water in the fuel cell can be frozen, and the reaction gas. If it is determined that the inside of the fuel cell may freeze after scavenging by the adjusting means, the scavenging means is configured to execute scavenging inside the fuel cell.

  According to a fourth aspect of the present invention, the scavenging means is driven by a power storage device, and the remaining amount of the power storage device is less than or equal to the total amount of power consumed for scavenging the reaction gas adjusting means and scavenging inside the fuel cell. If the reaction gas adjustment means can also be scavenged by scavenging inside the fuel cell, scavenging of the reaction gas adjustment means is stopped and scavenging inside the fuel cell can be executed. It is characterized by that.

  According to a fifth aspect of the present invention, there is provided a fuel cell for generating power by supplying an anode gas to the anode electrode and a cathode gas to the cathode electrode, a reaction gas pipe through which the reaction gas discharged from the fuel cell flows, and the reaction A reaction gas adjusting means for adjusting a flow of the reaction gas, a temperature detecting means for detecting a temperature of the reaction gas adjusting means, and a reaction gas adjusting means when power generation of the fuel cell is stopped. Scavenging means for removing the generated water of the fuel cell attached thereto, freezing determination means for determining whether or not the generated water is frozen by the reaction gas adjusting means based on a detection value of the temperature detecting means; And a method for stopping the fuel cell system, wherein scavenging by the scavenging means is performed when the freezing judging means determines that the generated water is likely to freeze by the reaction gas adjusting means. A device temperature measuring step for measuring the temperature of the reaction gas adjusting means located on the downstream side of the fuel cell; and a device scavenging determining step for determining whether or not scavenging for preventing freezing of the reaction gas adjusting means is necessary. And a device scavenging step for scavenging the reaction gas adjusting means.

  According to the first aspect of the present invention, when the temperature of the reaction gas adjusting means is detected and it is determined that the reaction gas adjusting means may freeze, the scavenging of the reaction gas adjusting means immediately after the fuel cell is stopped. Therefore, the droplets adhering to the reaction gas adjusting means can be surely removed. In addition, by determining whether or not scavenging of the reaction gas adjusting unit is performed based on the temperature of the reaction gas adjusting unit in this manner, for example, the reaction gas adjusting unit is frozen in a state where the warm-up of the fuel cell is completed. Even when it is determined that there is a risk, the droplets adhering to the reactive gas adjusting means can be reliably removed. Therefore, when the fuel cell system is started next time, the reaction gas adjusting means can be prevented from malfunctioning due to freezing, so that the fuel cell system can be started reliably.

  According to the second aspect of the present invention, when the amount of water generated in the fuel cell between the time when the fuel cell system is started and the time when the fuel cell system is stopped is less than a predetermined amount, the amount adhering to the reaction gas adjusting means is generated. Since the amount of water is also small, the possibility that the reaction gas adjusting means will malfunction due to freezing is reduced. Therefore, when the amount of generated water is small, the scavenging of the reaction gas adjusting unit is not executed, so that the energy for scavenging the reaction gas adjusting unit can be reduced.

  According to the invention described in claim 3, since the inside of the fuel cell can be prevented from freezing due to the produced water remaining inside the fuel cell, it is possible to prevent internal destruction caused by freezing of the produced water inside the fuel cell. Can do.

  According to the invention described in claim 4, since the scavenging of the reaction gas adjusting means and the fuel cell can be performed collectively even when the remaining amount of the power storage device is insufficient, the reaction gas adjusting means In addition, it is possible to prevent the generated water from freezing inside the fuel cell and making it impossible to generate power in the fuel cell system.

  According to the fifth aspect of the present invention, when the temperature of the reaction gas adjusting means is detected and it is determined that the reaction gas adjusting means may freeze, the scavenging of the reaction gas adjusting means immediately after the fuel cell is stopped. Therefore, the droplets adhering to the reaction gas adjusting means can be surely removed. In addition, by determining whether or not scavenging of the reaction gas adjusting unit is performed based on the temperature of the reaction gas adjusting unit in this manner, for example, the reaction gas adjusting unit is frozen in a state where the warm-up of the fuel cell is completed. Even when it is determined that there is a risk, the droplets adhering to the reactive gas adjusting means can be reliably removed. Therefore, when the fuel cell system is started next time, the reaction gas adjusting means can be prevented from malfunctioning due to freezing, so that the fuel cell system can be started reliably.

(First embodiment)
Next, a first embodiment of a fuel cell system according to the present invention will be described with reference to FIGS. In the present embodiment, a case where the fuel cell system is mounted on a vehicle will be described.
(Fuel cell system)
FIG. 1 is a schematic configuration diagram of a fuel cell system.
As shown in FIG. 1, the fuel cell 11 of the fuel cell system 10 is a solid polymer membrane fuel cell that generates electric power by an electrochemical reaction between an anode gas such as hydrogen gas and a cathode gas such as air. An anode gas supply pipe 23 is connected to the anode gas supply communication hole 13 (inlet side of the anode gas passage 21) formed in the fuel cell 11, and a hydrogen tank 30 is connected to the upstream end thereof. A cathode gas supply pipe 24 is connected to the cathode gas supply communication hole 15 (inlet side of the cathode gas flow path 22) formed in the fuel cell 11, and an air compressor 33 is connected to the upstream end thereof. Yes. An anode off-gas exhaust pipe 35 (cathode gas flow path 22) is connected to the anode off-gas discharge communication hole 14 (exit side of the anode gas flow path 21) formed in the fuel cell 11. Is connected to a cathode offgas discharge pipe 38.

  Further, the hydrogen gas supplied from the hydrogen tank 30 to the anode gas supply pipe 23 is decompressed by a regulator (not shown), then passes through the ejector 26 and is supplied to the anode gas flow path 21 of the fuel cell 11. An electromagnetically driven solenoid valve 25 is provided in the vicinity of the downstream side of the hydrogen tank 30 so that the supply of hydrogen gas from the hydrogen tank 30 can be shut off.

  The anode off-gas discharge pipe 35 is connected to the ejector 26 so that the anode off-gas that has passed through the fuel cell 11 can be reused as the anode gas of the fuel cell 11 again. Further, the anode off-gas discharge pipe 35 is provided with two pipes branched in the middle, one being an anode air discharge pipe 36 and the other being a purge gas discharge pipe 37. Both the anode air discharge pipe 36 and the purge gas discharge pipe 37 are connected to the dilution box 31. The anode air discharge pipe 36 is provided with an electromagnetically driven anode air discharge valve 51, and the purge gas discharge pipe 37 is provided with an electromagnetically driven purge valve 52. The anode air discharge pipe 36 has a pipe diameter larger than that of the purge gas discharge pipe 37.

Next, air (cathode gas) is pressurized by the air compressor 33, passes through the cathode gas supply pipe 24, and is then supplied to the cathode gas flow path 22 of the fuel cell 11. After this oxygen in the air is used as an oxidizing agent for power generation, it is discharged from the fuel cell 11 to the cathode offgas discharge pipe 38 as cathode offgas. The cathode offgas discharge pipe 38 is connected to the dilution box 31 and then exhausted to the outside of the vehicle. A back pressure valve 34 is provided in the cathode off gas discharge pipe 38.
Here, a temperature sensor 55 is provided in the immediate vicinity of the back pressure valve 34 on the upstream side of the back pressure valve 34 (between the fuel cell 11 and the back pressure valve 34). The temperature sensor 55 can detect substantially the same temperature as the temperature of the back pressure valve 34. A detection result (sensor output) from the temperature sensor 55 is transmitted to a control unit (ECU) 45, and based on the detection result, it is determined whether or not scavenging of the back pressure valve 34 (which will be described in detail later) is executed. Is configured to do.

  Further, in the cathode gas supply pipe 24 connecting the air compressor 33 and the fuel cell 11, the pipe is branched and one end of the scavenging gas introduction pipe 53 is connected. The other end of the scavenging gas introduction pipe 53 is connected between the ejector 26 and the fuel cell 11 in the anode gas supply pipe 23. That is, the air pressurized by the air compressor 33 can be supplied to the anode gas passage 21 of the fuel cell 11. The scavenging gas introduction pipe 53 is provided with an electromagnetically driven solenoid valve 54 so that the supply of air from the air compressor 33 can be shut off.

  Further, a temperature sensor 41 is provided immediately after (on the downstream side of) the anode off gas discharge communication hole 14 in the anode off gas discharge pipe 35. The temperature sensor 41 can detect substantially the same temperature as the temperature inside the fuel cell 11. A detection result (sensor output) from the temperature sensor 41 is transmitted to a control unit (ECU) 45, and based on the detection result, whether or not scavenging inside the fuel cell 11 (which will be described in detail later) is executed. Is configured to determine.

  FIG. 2 is a schematic block diagram of the control device 45. As shown in FIG. 2, the control device 45 has a possibility that the back pressure valve 34 may freeze based on the detection result of the generated water amount detection unit 47 that detects the generated water amount generated by the fuel cell 11 and the temperature sensor 55. A back pressure valve freezing determination unit 48 that determines whether or not, a stop time detection unit 49 that counts the time since the fuel cell system 10 is stopped, and a time that is counted by the stop time detection unit 49 for a predetermined time And a fuel cell internal freezing determination unit 50 that determines whether or not the inside of the fuel cell 11 is likely to freeze based on the detection result of the temperature sensor 41.

  Further, the control device 45 can supply a predetermined amount of hydrogen gas from the hydrogen tank 30 to the fuel cell 11 by controlling the electromagnetic valve 25 according to the output required for the fuel cell 11. . The control device 45 drives the air compressor 33 according to the output required for the fuel cell 11 to supply a predetermined amount of air to the fuel cell 11 and controls the back pressure valve 34 to control the cathode gas flow path. It is comprised so that the supply pressure of the air to 22 can be adjusted.

  Then, when scavenging the inside of the fuel cell 11 or the like according to an instruction from the fuel cell internal freezing determination unit 50, the electromagnetic valve 54 of the scavenging gas introduction pipe 53 is controlled to supply a predetermined amount of air to the anode side. It is configured to be able to.

(How to stop the fuel cell system)
Next, a method for stopping the fuel cell system 10 in the present embodiment will be described.
FIG. 3 is a flowchart showing a method for stopping the fuel cell system 10.
As shown in FIG. 3, in step S <b> 11, after turning off an ignition switch (not shown) that is a start signal of the fuel cell system 10, the generated water amount detection unit 47 until the ignition switch is turned off in the fuel cell 11. The amount of generated water generated during the period is detected, and when the generated water of a predetermined amount or more is generated, the process proceeds to step S12, and when only the generated water less than the predetermined amount is generated, the process proceeds to step S15. For example, the amount of generated water is calculated based on an integrated current amount detected from a current sensor (not shown) provided in the fuel cell 11.

  In step S12, the temperature of the back pressure valve 34 is detected. In the present embodiment, the detection result of the temperature sensor 55 provided in the vicinity of the back pressure valve 34 is estimated as the temperature of the back pressure valve 34.

  In step S <b> 13, the back pressure valve freezing determination unit 48 determines whether or not the back pressure valve 34 is likely to freeze according to the detection result of the temperature sensor 55. For example, when the temperature detected by the temperature sensor 55 is 5 ° C. or lower, it is determined that the back pressure valve 34 may freeze. If it is determined that the back pressure valve 34 is likely to freeze, the process proceeds to step S14. If it is determined that there is no possibility that the back pressure valve 34 will freeze, the process proceeds to step S15.

  In step S14, scavenging of the back pressure valve 34 is executed. Specifically, the electromagnetic valve 54 of the scavenging gas introduction pipe 53 is closed, and the back pressure valve 34 of the cathode offgas discharge pipe 38 is opened. Then, by driving the air compressor 33, the pressurized air is supplied to the piping on the cathode side, thereby scavenging the back pressure valve 34.

  In step S <b> 15, the fuel cell internal freezing determination unit 50 determines whether there is a possibility that the inside of the fuel cell 11 is frozen according to the detection result of the temperature sensor 41. For example, when the temperature detected by the temperature sensor 41 is 5 ° C. or lower, it is determined that the inside of the fuel cell 11 may be frozen. If it is determined that the inside of the fuel cell 11 may be frozen, the process proceeds to step S16, and if it is determined that there is no possibility that the fuel cell 11 is frozen, the process proceeds to step S17.

  In step S16, scavenging inside the fuel cell 11 is executed. Specifically, the solenoid valve 54 of the scavenging gas introduction pipe 53, the anode air discharge valve 51 of the anode air discharge pipe 36, the purge valve 52 of the purge gas discharge pipe 37, and the back pressure valve 34 of the cathode off gas discharge pipe 38 are opened. By driving the air compressor 33, the compressed air is supplied to the anode side and cathode side piping and the like, thereby scavenging the fuel cell 11 inside. When the scavenging inside the fuel cell 11 is executed, the process ends.

  In step S17, it is determined whether or not the ignition switch that is the activation signal of the fuel cell system 10 is turned on. If the ignition switch is still in the off state, the process returns to step S15, and if the ignition switch is turned on, the process ends. . In addition, what is necessary is just to make it process step S15-S17 every 5 minutes by the stop time detected by the stop time detection part 49, for example.

  Note that the electric power necessary for the above-described scavenging of the back pressure valve 34 and scavenging inside the fuel cell 11 is secured from, for example, a battery (not shown) that stores the electric power of the fuel cell.

  According to the present embodiment, when the temperature of the back pressure valve 34 is detected and it is determined that the back pressure valve 34 may be frozen, the back pressure valve 34 is scavenged immediately after the fuel cell 11 stops generating power. The droplets adhering to the back pressure valve 34 can be reliably removed. In addition, the back pressure valve freezing determination unit 48 determines whether or not the back pressure valve 34 needs to be scavenged based on the temperature of the back pressure valve 34 in this way, so that the back pressure valve 34 is warmed up. Even when it is determined that there is a risk of the 34 being frozen, the droplets adhering to the back pressure valve 34 can be reliably removed. Therefore, when the fuel cell system 10 is started next time, the back pressure valve 34 can be prevented from malfunctioning due to freezing, so that the fuel cell system 10 can be reliably started.

  In addition, when the amount of water generated by the fuel cell 11 between the start and stop of the fuel cell system 10 is less than or equal to a predetermined amount, the amount of generated water adhering to the back pressure valve 34 is small, so the back pressure valve 34 Is less likely to malfunction due to freezing. Therefore, when the amount of generated water is small, the scavenging of the back pressure valve 34 is not executed so that the energy for scavenging the back pressure valve 34 can be reduced.

  Further, the fuel cell internal freezing determination unit 50 is provided, and when it is determined that the inside of the fuel cell 11 may be frozen, the inside of the fuel cell 11 can be scavenged. As a result, the inside of the fuel cell 11 can be prevented from freezing. Therefore, internal destruction caused by freezing of the generated water inside the fuel cell 11 can be prevented.

(Second embodiment)
Next, a second embodiment of the fuel cell system according to the present invention will be described with reference to FIGS. The present embodiment is different from the first embodiment only in the scavenging method, and the configuration of the fuel cell system is substantially the same as that of the first embodiment. Is omitted.

(How to stop the fuel cell system)
A method for stopping the fuel cell system 10 in the present embodiment will be described.
FIG. 4 is a flowchart showing a method for stopping the fuel cell system 10.
As shown in FIG. 4, in step S <b> 21, the generated water amount detection unit 47 detects the generated water amount generated until the ignition switch is turned off in the fuel cell 11, and generated water of a predetermined amount or more is generated. If the generated water is less than a predetermined amount, the process proceeds to step S26.

  In step S22, the temperature of the back pressure valve 34 is detected. In the present embodiment, the detection result of the temperature sensor 55 provided in the vicinity of the back pressure valve 34 is estimated as the temperature of the back pressure valve 34.

  In step S <b> 23, the back pressure valve freezing determination unit 48 determines whether or not the back pressure valve 34 may freeze according to the detection result of the temperature sensor 55. For example, when the temperature detected by the temperature sensor 55 is 5 ° C. or lower, it is determined that the back pressure valve 34 may freeze. If it is determined that the back pressure valve 34 is likely to freeze, the process proceeds to step S24. If it is determined that there is no possibility that the back pressure valve 34 will freeze, the process proceeds to step S26.

  In step S24, it is determined whether the amount of power stored in the battery is greater than the total amount of power required for scavenging the back pressure valve 34 and scavenging inside the fuel cell 11 predicted to be executed thereafter. To do. If the remaining amount of the battery is equal to or greater than the total amount of power required for both scavenging operations, the process proceeds to step S25, and if not, the process proceeds to step S27.

  In step S25, scavenging of the back pressure valve 34 is executed. Specifically, the electromagnetic valve 54 of the scavenging gas introduction pipe 53 is closed, and the back pressure valve 34 of the cathode offgas discharge pipe 38 is opened. Then, by driving the air compressor 33, the pressurized air is supplied to the piping on the cathode side, thereby scavenging the back pressure valve 34.

  In step S <b> 26, the fuel cell internal freezing determination unit 50 determines whether there is a possibility that the inside of the fuel cell 11 is frozen according to the detection result of the temperature sensor 41. For example, when the temperature detected by the temperature sensor 41 is 5 ° C. or lower, it is determined that the inside of the fuel cell 11 may be frozen. If it is determined that the inside of the fuel cell 11 is likely to freeze, the process proceeds to step S27. If it is determined that there is no possibility that the fuel cell 11 is frozen, the process proceeds to step S28.

In step S27, scavenging inside the fuel cell 11 is executed. Specifically, the solenoid valve 54 of the scavenging gas introduction pipe 53, the anode air discharge valve 51 of the anode air discharge pipe 36, the purge valve 52 of the purge gas discharge pipe 37, and the back pressure valve 34 of the cathode off gas discharge pipe 38 are opened. By driving the air compressor 33, the compressed air is supplied to the anode side and cathode side piping and the like, thereby scavenging the fuel cell 11 inside. When the scavenging inside the fuel cell 11 is executed, the process ends.
In addition, since the remaining amount of the battery is low in step S24, when scavenging the fuel cell 11 without performing scavenging of the back pressure valve 34, scavenging of the back pressure valve 34 corresponding to step S25 described above is not performed. In step S27, the back pressure valve 34 is always opened to perform scavenging, so that the droplets adhering to the back pressure valve 34 can be removed as much as possible.

The above flow will be described in more detail.
As shown in FIG. 5, for example, the amount of power stored in the battery when power generation is stopped is 100, the amount of power required for scavenging the back pressure valve 34 is 50, and the amount of power required for scavenging inside the fuel cell 11 is 80. And At this time, if the scavenging of the back pressure valve 34 is executed, the amount of electric power for executing the antifreezing scavenging inside the fuel cell 11 becomes insufficient, and the inside of the fuel cell 11 may be damaged due to freezing. On the other hand, even if scavenging of the back pressure valve 34 is executed with the remaining 20 electric energy in order to surely execute the antifreezing scavenging inside the fuel cell 11, since the countermeasure is insufficient, the droplets adhering to the back pressure valve 34 Cannot be removed reliably. Therefore, the scavenging of the fuel cell 11 is performed without performing the scavenging of the back pressure valve 34, and the scavenging of the back pressure valve 34 is also performed, so that the fuel cell 11 is damaged and the back pressure valve 34 is frozen. Can be prevented collectively.

  In step S28, it is determined whether or not the ignition switch that is the activation signal of the fuel cell system 10 is turned on. If the ignition switch is still in the off state, the process returns to step S26, and if the ignition switch is turned on, the process ends. . In addition, what is necessary is just to make it process step S26-S28 every 5 minutes by the stop time detected by the stop time detection part 49, for example.

  According to this embodiment, in addition to the effects of the first embodiment, scavenging of the back pressure valve 34 and the fuel cell 11 can be performed collectively even when the remaining amount of the battery is insufficient. Therefore, it is possible to prevent the generated water from being frozen in the back pressure valve 34 and the fuel cell 11 and making it impossible to generate power in the fuel cell system 10.

Note that the present invention is not limited to the above-described embodiment, and includes various modifications made to the above-described embodiment without departing from the spirit of the present invention. That is, the specific structure and configuration described in the embodiment are merely examples, and can be changed as appropriate.
For example, in this embodiment, the temperature sensor that detects the temperature of the back pressure valve is attached to the cathode offgas discharge pipe, but the temperature of the back pressure valve may be directly detected, and the temperature of the refrigerant, gas, and peripheral auxiliary equipment May be adopted as an alternative temperature. Further, the temperature sensor may be attached not only to one place but also to a plurality of places (for example, upstream and downstream of the back pressure valve). In that case, either temperature is detected or each temperature sensor is detected. You may make it obtain | require the average value of.

1 is a schematic configuration diagram of a fuel cell system in an embodiment of the present invention. It is a schematic block diagram of the control apparatus in embodiment of this invention. It is a flowchart which shows the stop method of the fuel cell system in 1st embodiment of this invention. It is a flowchart which shows the stop method of the fuel cell system in 2nd embodiment of this invention. It is explanatory drawing explaining the stop method of the fuel cell system in 2nd embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Fuel cell system 11 ... Fuel cell 33 ... Air compressor (scavenging means) 34 ... Back pressure valve (reaction gas adjustment means) 38 ... Cathode off-gas discharge piping (reaction gas piping) 47 ... Generated water amount detection part (generated water amount detection means) 48 ... Back pressure valve freezing determination unit (freezing determination unit) 50 ... Fuel cell internal freezing determination unit (fuel cell internal freezing determination unit) 55 ... Temperature sensor (temperature detection unit)

Claims (5)

A fuel cell for generating electricity by supplying an anode gas to the anode electrode and a cathode gas to the cathode electrode; and
A reaction gas pipe through which the reaction gas discharged from the fuel cell flows;
A reaction gas adjusting means arranged in the reaction gas pipe to adjust the flow of the reaction gas, and a fuel cell system comprising:
Temperature detecting means for detecting the temperature of the reaction gas adjusting means;
Scavenging means for removing generated water of the fuel cell attached to the reaction gas adjusting means during power generation stop of the fuel cell;
Freezing determination means for determining whether or not the generated water is frozen in the reaction gas adjustment means based on the detection value of the temperature detection means,
A fuel cell system configured to be able to perform scavenging by the scavenging means when it is determined by the freezing determination means that the generated water is likely to be frozen by the reaction gas adjusting means. During the power generation of the fuel cell, it has a generated water amount detection means for detecting the amount of generated water generated in the fuel cell,
2. The fuel cell system according to claim 1, wherein when the amount of generated water is equal to or less than a predetermined amount, scavenging of the reaction gas adjusting unit is not executed.   A fuel cell internal freezing determination means for determining whether or not the generated water inside the fuel cell can be frozen; The fuel cell system according to claim 1, wherein the scavenging means is configured to execute scavenging inside the fuel cell. The scavenging means is driven by a power storage device,
The remaining amount of the power storage device is less than or equal to the total amount of power consumed for scavenging the reaction gas adjusting means and scavenging inside the fuel cell, and the reaction gas adjusting means is also caused by scavenging inside the fuel cell. 4. The fuel cell system according to claim 3, wherein when scavenging is possible, the scavenging of the reaction gas adjusting unit is stopped and scavenging inside the fuel cell can be executed. 5. A fuel cell for generating electricity by supplying an anode gas to the anode electrode and a cathode gas to the cathode electrode; and
A reaction gas pipe through which the reaction gas discharged from the fuel cell flows;
A reaction gas adjusting means arranged in the reaction gas pipe for adjusting the flow of the reaction gas;
Temperature detecting means for detecting the temperature of the reaction gas adjusting means;
Scavenging means for removing generated water of the fuel cell attached to the reaction gas adjusting means during power generation stop of the fuel cell;
Freezing determination means for determining whether or not the generated water is frozen by the reaction gas adjustment means based on a detection value of the temperature detection means,
A method of stopping a fuel cell system, wherein scavenging by the scavenging means is performed when the freezing judgment means determines that the generated water may be frozen by the reaction gas adjusting means,
A device temperature measuring step for measuring the temperature of the reaction gas adjusting means located on the downstream side of the fuel cell;
A device scavenging determination step for determining whether scavenging for freezing prevention of the reaction gas adjusting means is necessary;
A device scavenging step for scavenging the reaction gas adjusting means; and a method for stopping the fuel cell system.

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