JP2009146656A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system for reducing the amount of emission of hydrogen exhaust gas as surely discharging moisture at purging a hydrogen exhaust gas, and for realizing downsizing. <P>SOLUTION: The fuel cell system 1 includes a fuel cell 10 generating power by reacting hydrogen gas and air, a hydrogen discharge channel 44 supplying hydrogen exhaust gas discharged from an anode side of the fuel cell 10 to the anode side of the cell 10 again, and air discharge channel 42 discharging air exhaust gas discharged from a cathode side of the fuel cell 10 to outside. Further, the system includes a hydrogen chamber 25, a first chamber flow channel 46 communicating with the hydrogen discharge channel 44 and the hydrogen chamber 25 and with a chamber control valve 461 fitted, and a second chamber flow channel 47 communicating with the hydrogen chamber 25 and the air discharge channel 42 and with a discharge control valve 471 fitted. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell system. In detail, it is related with the fuel cell system mounted in a motor vehicle.

  In recent years, fuel cell systems have attracted attention as a new power source for automobiles. The fuel cell system includes, for example, a fuel cell that generates a power by chemically reacting a reaction gas, a reaction gas supply device that supplies the reaction gas to the fuel cell via a reaction gas channel, and a control that controls the reaction gas supply device An apparatus.

  The fuel cell has, for example, a stack structure in which several tens to several hundreds of cells are stacked. Here, each cell is configured by sandwiching a membrane electrode structure (MEA) between a pair of separators. The membrane electrode structure includes two electrodes, an anode electrode (anode) and a cathode electrode (cathode), and these electrodes. And a solid polymer electrolyte membrane sandwiched between the two.

  When hydrogen gas is supplied to the anode electrode of this fuel cell and air containing oxygen is supplied to the cathode electrode, power is generated by an electrochemical reaction.

In the fuel cell system described above, hydrogen purge is performed to discharge impurities in the anode system and moisture in the fuel cell (see Patent Document 1). Hydrogen purging is a process of diluting hydrogen exhaust gas containing impurities with exhaust gas by using a diluting device, reducing the hydrogen concentration to a safe level, and discharging it to the atmosphere.
JP 2003-132915 A

By the way, at the time of hydrogen purge, in order to discharge the water in the hydrogen circulation flow path, it is necessary to discharge a certain amount of hydrogen exhaust gas at a stretch.
However, since the capacity of the diluting device is determined, the purge amount is adjusted based on the capacity of the diluting device, and moisture may not be discharged reliably.

Therefore, a method of increasing the capacity of the diluting device can be considered so that a certain amount of hydrogen exhaust gas can be discharged at a stretch. However, this method has a problem that the diluting device becomes large.
In addition, if a large amount of hydrogen exhaust gas is purged at once, hydrogen exhaust gas having a high hydrogen concentration that can be circulated and reused is discharged to the atmosphere, resulting in a problem of reduced energy efficiency.

  An object of the present invention is to provide a fuel cell system that can reduce the discharge amount of hydrogen exhaust gas while reliably discharging moisture when purging the hydrogen exhaust gas, and can further reduce the size.

  A fuel cell system (for example, a fuel cell system 1 described later) of the present invention includes a fuel cell (for example, a fuel cell 10 described later) that generates power by reacting hydrogen gas and an oxidant gas, and an anode side of the fuel cell. The hydrogen exhaust gas discharged from the fuel cell is again supplied to the anode side of the fuel cell (for example, a hydrogen discharge channel 44 described later), and the oxidant exhaust gas discharged from the cathode side of the fuel cell is externally supplied. An oxidant gas discharge passage (for example, an air discharge passage 42 described later) for discharging to a hydrogen chamber, a hydrogen chamber (for example, a hydrogen chamber 25 described later), the hydrogen circulation passage, A first chamber flow path (for example, a first chamber flow path 46 described later) provided with a chamber control valve (for example, a chamber control valve 461 described later) in communication with the hydrogen chamber; A second chamber flow path (for example, a second chamber flow path 47 to be described later) provided with a discharge control valve (for example, a discharge control valve 471 to be described later) in communication with the element chamber and the oxidant gas discharge flow path; It is characterized by providing.

  According to the present invention, it is possible to store hydrogen exhaust gas in the hydrogen chamber and then return the stored hydrogen exhaust gas to the hydrogen circulation channel (hereinafter referred to as first hydrogen exhaust gas processing). Further, it is also possible to store hydrogen exhaust gas in the hydrogen chamber and then discharge the stored hydrogen exhaust gas to the oxidant discharge flow path (hereinafter referred to as second hydrogen exhaust gas processing).

Hereinafter, the first hydrogen exhaust gas treatment will be described.
First, the pressure in the hydrogen chamber is made lower than the pressure in the hydrogen circulation flow path, the exhaust control valve is closed, and the chamber control valve is opened. Then, the hydrogen exhaust gas in the hydrogen circulation channel flows into the hydrogen chamber via the first chamber channel, and at the same time, the moisture contained in the hydrogen exhaust gas also flows into the hydrogen chamber due to the pressure pulsation of the hydrogen exhaust gas. Thereby, the water | moisture content in a fuel cell and a hydrogen circulation flow path can be reliably discharged | emitted to a hydrogen chamber.

  Next, the chamber control valve is closed. Thereby, hydrogen exhaust gas is stored in the hydrogen chamber.

  Thereafter, the pressure in the hydrogen chamber is set higher than the pressure in the hydrogen circulation channel, and the chamber control valve is opened. Then, the hydrogen exhaust gas in the hydrogen chamber flows into the hydrogen circulation channel again. At this time, only moisture contained in the hydrogen exhaust gas remains in the hydrogen chamber. Therefore, since it is not necessary to discharge a large amount of hydrogen exhaust gas at a time in order to discharge moisture as in the prior art, the amount of hydrogen exhaust gas discharged can be reduced.

  In addition, when storing hydrogen exhaust gas in the hydrogen chamber, the pressure in the hydrogen chamber can be made close to the pressure of the hydrogen circulation flow path, that is, a somewhat high pressure. It is possible to physically store a large amount of hydrogen exhaust gas by efficiently using. Therefore, the system can be downsized.

Hereinafter, the second hydrogen exhaust gas treatment will be described.
The procedure until the hydrogen exhaust gas is stored in the hydrogen chamber is the same as in the first control method.
After storing the hydrogen exhaust gas in the hydrogen chamber, the pressure in the oxidant exhaust gas flow path is made lower than the pressure in the hydrogen chamber, the discharge control valve is opened, and the hydrogen exhaust gas is passed through the second chamber flow path. Are gradually discharged to the oxidant exhaust gas flow path. Thereby, since it is not necessary to discharge | emit a lot of hydrogen exhaust gas at once in order to discharge | emit water like the past, the discharge | emission amount of hydrogen exhaust gas can be reduced.
Further, since the hydrogen exhaust gas can be mixed with the oxidant exhaust gas using the pressure difference between the hydrogen exhaust gas and the oxidant exhaust gas, the hydrogen concentration can be easily controlled.

  The control method for a fuel cell system according to the present invention includes a fuel cell that generates electricity by reacting hydrogen gas and oxidant gas, and hydrogen exhaust gas discharged from the anode side of the fuel cell. A control circuit for a fuel cell system, comprising: a hydrogen circulation channel for supplying to a fuel cell; and an oxidant gas discharge channel for discharging an oxidant off-gas discharged from the cathode side of the fuel cell to the outside, The hydrogen circulation channel and the hydrogen chamber communicate with each other and a chamber control valve is provided; the hydrogen chamber and the oxidant gas discharge channel communicate with each other; and a discharge control valve is provided. A first step of closing the discharge control valve and opening the chamber control valve, and the pressure in the hydrogen chamber is adjusted to discharge the oxidant discharge flow. A second step of closing the chamber control valve, the exhaust control valve is opened, and a pressure difference between the hydrogen chamber and the oxidant gas discharge flow path is utilized. And a third step of discharging the hydrogen exhaust gas stored in the hydrogen chamber into the oxidant gas discharge flow path.

  The predetermined pressure may be appropriately set as long as it is equal to or lower than the pressure of the hydrogen circulation flow path and higher than the pressure of the oxidant gas discharge flow path. Here, the closer the predetermined pressure is to the pressure of the hydrogen circulation channel, the more effectively the pressure difference can be utilized when discharging the hydrogen exhaust gas stored in the hydrogen chamber to the oxidant gas discharge channel.

  According to the present invention, the same effect as described above can be obtained.

  In this case, in the third step, when opening the discharge control valve, based on the hydrogen concentration downstream of the merging point with the second chamber flow path in the oxidant gas discharge flow path, It is preferable to control the opening degree of the discharge control valve.

  According to this invention, when opening the discharge control valve, the opening degree of the discharge control valve is controlled based on the hydrogen concentration after mixing the hydrogen exhaust gas with the oxidant exhaust gas. The hydrogen concentration can be accurately controlled.

  In this case, in the third step, when the discharge control valve is opened, the discharge control valve is controlled based on the pressure in the hydrogen chamber and the flow rate of the oxidant exhaust gas flowing through the oxidant gas discharge passage. It is preferable to control the opening.

If the hydrogen concentration in the chamber is known, the hydrogen concentration after mixing the hydrogen exhaust gas with the oxidant exhaust gas is determined based on the pressure in the hydrogen chamber and the flow rate of the oxidant exhaust gas flowing through the oxidant gas discharge channel. It can be calculated.
Therefore, according to the present invention, when opening the discharge control valve, the opening degree of the discharge control valve is controlled based on the pressure in the hydrogen chamber and the flow rate of the oxidant exhaust gas flowing through the oxidant gas discharge passage. Therefore, the hydrogen concentration of the gas discharged to the outside can be accurately controlled.

  In the fuel cell system of the present invention, a fuel cell that generates electricity by reacting hydrogen gas and oxidant gas, and hydrogen exhaust gas discharged from the anode side of the fuel cell are again supplied to the anode side of the fuel cell. A fuel cell system, comprising: a hydrogen circulation channel; and an oxidant gas discharge channel that discharges oxidant exhaust gas discharged from the cathode side of the fuel cell to the outside, wherein the hydrogen chamber and the hydrogen circulation channel And a first chamber flow path that communicates with the hydrogen chamber and is provided with a chamber control valve.

  According to this invention, there exists an effect similar to the above-mentioned 1st hydrogen exhaust gas treatment.

  The control method for a fuel cell system according to the present invention includes a fuel cell that generates electricity by reacting hydrogen gas and oxidant gas, and hydrogen exhaust gas discharged from the anode side of the fuel cell. A control circuit for a fuel cell system, comprising: a hydrogen circulation channel for supplying to a fuel cell; and an oxidant gas discharge channel for discharging an oxidant off-gas discharged from the cathode side of the fuel cell to the outside, The hydrogen circulation channel and the hydrogen chamber communicate with each other and a chamber control valve is provided; the hydrogen chamber and the oxidant gas discharge channel communicate with each other; and a discharge control valve is provided. A first step of increasing the pressure in the hydrogen circulation path, opening the chamber control valve, and the pressure in the hydrogen chamber is a first pressure value. A second step of closing the chamber control valve, a third step of reducing the pressure in the hydrogen circulation path to a second pressure value lower than the first pressure value, and opening the chamber control valve. And a fourth step of closing the chamber control valve when the pressure in the hydrogen chamber reaches a third pressure value lower than the first pressure value and greater than or equal to the second pressure value. Features.

  According to this invention, there exists an effect similar to the above-mentioned 1st hydrogen exhaust gas treatment.

  According to the present invention, it is possible to store hydrogen exhaust gas in the hydrogen chamber and then return the stored hydrogen exhaust gas to the hydrogen circulation channel. Further, it is possible to store hydrogen exhaust gas in the hydrogen chamber and then discharge the stored hydrogen exhaust gas to the oxidant discharge channel. Thereby, the water | moisture content in a fuel cell and a hydrogen circulation channel can be reliably discharged | emitted to a hydrogen chamber. In addition, since it is not necessary to discharge a large amount of hydrogen exhaust gas at a time in order to discharge moisture as in the prior art, the amount of hydrogen exhaust gas discharged can be reduced. Further, since the hydrogen exhaust gas can be mixed with the oxidant exhaust gas using the pressure difference between the hydrogen exhaust gas and the oxidant exhaust gas, the hydrogen concentration can be easily controlled. Further, as compared with the case where a diluting device is used, a larger amount of hydrogen exhaust gas can be physically stored by efficiently using the volume. Therefore, the system can be downsized.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description of the embodiments, the same constituent elements are denoted by the same reference numerals, and the description thereof is omitted or simplified.
[First Embodiment]
FIG. 1 is a block diagram of a fuel cell system 1 according to the first embodiment of the present invention.
A fuel cell system 1 is mounted on a vehicle and generates a power by reacting a reaction gas, a supply device 20 for supplying hydrogen gas or air (air) to the fuel cell 10, and a control for controlling them. Device 30.

  Such a fuel cell 10 generates power by an electrochemical reaction when hydrogen gas is supplied to the anode electrode (anode) side and air containing oxygen as an oxidant gas is supplied to the cathode electrode (cathode) side.

  The supply device 20 includes an air pump 21 that supplies air to the cathode electrode side of the fuel cell 10, a hydrogen tank 22 and ejector 24 that supply hydrogen gas to the anode electrode side, and a dilution that processes the gas discharged from the fuel cell 10. And a hydrogen chamber 25.

  The air pump 21 is connected to the cathode electrode side of the fuel cell 10 via an air supply path 41.

  On the cathode electrode side of the fuel cell 10, an air discharge path 42 as an oxidant gas discharge path communicating with the outside is connected, and the above-described diluter 23 is provided in the middle of the air discharge path 42.

The hydrogen tank 22 is connected to the anode electrode side of the fuel cell 10 through a hydrogen supply path 43.
In the hydrogen supply path 43, a primary regulator 431, a shut-off valve 432, a secondary regulator 433, a heat exchanger 434, and an ejector 24 are provided in this order from the upstream side.

  A hydrogen discharge path 44 as a hydrogen circulation flow path is connected to the anode electrode side of the fuel cell 10, and this hydrogen discharge path 44 is connected to the diluter 23. A purge valve 441 is provided in the hydrogen discharge path 44. Further, in the hydrogen discharge path 44, on the fuel cell 10 side of the purge valve 441, the hydrogen discharge path 44 is branched to become a hydrogen recirculation path 45, and the hydrogen recirculation path 45 is connected to the ejector 24 described above. The hydrogen recirculation path 45 is provided with a check valve 451 that prevents the backflow of hydrogen gas.

  A first chamber flow path 46 is connected to the hydrogen discharge path 44, and the first chamber flow path 46 communicates the hydrogen discharge path 44 and the hydrogen chamber 25. In addition, a chamber control valve 461 is provided in the first chamber flow path 46. Examples of the structure of the chamber control valve 461 include a valve that is operated by an electric actuator such as a solenoid, a regulator that operates by a pressure difference, and a check valve.

  The ejector 24 collects the hydrogen off-gas discharged from the fuel cell 10 to the hydrogen discharge path 44 through the hydrogen reflux path 45 and returns it to the hydrogen supply path 43.

  The control device 30 includes a first hydrogen exhaust gas processing unit 31, controls the supply device 20 to generate power in the fuel cell 10, and generates hydrogen discharged from the fuel cell 10 by the first hydrogen exhaust gas processing unit 31. Treat the exhaust gas.

Specifically, the control device 30 generates power in the fuel cell 10 according to the following procedure.
That is, the purge valve 441 is closed and the shut-off valve 432 is opened. Then, by driving the air pump 21, air is supplied to the cathode side of the fuel cell 10 through the air supply path 41. At the same time, hydrogen gas is supplied from the hydrogen tank 22 to the anode side of the fuel cell 10 through the hydrogen supply path 43.

  The hydrogen exhaust gas and air supplied to the fuel cell 10 are supplied to the power generation system, and then flow into the hydrogen discharge path 44 and the air discharge path 42 together with residual water such as produced water on the anode side from the fuel cell 10. Since the purge valve 441 is closed, the hydrogen exhaust gas flowing into the hydrogen discharge path 44 is returned to the hydrogen supply path 43 through the hydrogen reflux path 45 and supplied again to the fuel cell.

  Thereafter, by opening the purge valve 441 at an appropriate opening degree, the hydrogen exhaust gas discharged to the hydrogen discharge path 44 flows into the diluter 23. The hydrogen exhaust gas flowing into the diluter 23 is diluted with the air exhaust gas flowing through the air discharge passage 42 in the diluter 23 and discharged to the outside.

The operation of the first hydrogen exhaust gas processing unit 31 will be described with reference to the flowchart of FIG.
In ST1, the pressure in the hydrogen discharge path 44 is increased to the first pressure value. This first pressure value is higher than the pressure value in the hydrogen chamber.
In ST2, the chamber control valve 461 is opened. Then, since the hydrogen exhaust gas in the hydrogen discharge path 44 flows into the hydrogen chamber 25, the pressure in the hydrogen chamber 25 increases.

In ST3, it is determined whether or not the pressure in the hydrogen chamber 25 has reached the pressure in the hydrogen discharge path 44, that is, the first pressure value. If this determination is NO, the process returns to ST2, and if YES, the process moves to ST4.
In ST4, the chamber control valve 461 is closed, and the pressure in the hydrogen discharge path 44 is lowered to a second pressure value lower than the first pressure value. Thereby, the pressure in a hydrogen chamber is made higher than the pressure in a hydrogen circulation channel.

In ST5, the chamber control valve 461 is opened. Then, since the hydrogen gas in the hydrogen chamber 25 flows into the hydrogen discharge path 44, the pressure in the hydrogen discharge path 44 increases.
In ST6, it is determined whether or not the pressure in the hydrogen chamber 25 has reached a third pressure value lower than the first pressure value and greater than or equal to the second pressure value, here the second pressure value. If this determination is NO, the process returns to ST5, and if YES, the process moves to ST7.
In ST7, the chamber control valve 461 is closed.

FIG. 3 is a timing chart of the operation of the first hydrogen exhaust gas treatment unit 31.
During the period from time t1 to t2, the pressure in the hydrogen discharge path 44 increases from the second pressure value to the first pressure value.
At time t3, the chamber control valve 461 is opened. Then, since the hydrogen exhaust gas in the hydrogen discharge path 44 flows into the hydrogen chamber 25, the pressure in the hydrogen chamber 25 increases.
At time t4, since the pressure in the hydrogen chamber 25 has reached the pressure in the hydrogen discharge passage 44, that is, the first pressure value, the chamber control valve 461 is closed.
During the period from time t5 to t6, the pressure in the hydrogen discharge path 44 is reduced to the second pressure value.

At time t7, the chamber control valve 461 is opened. Then, since the hydrogen gas in the hydrogen chamber 25 flows into the hydrogen discharge path 44, the pressure in the hydrogen discharge path 44 increases. Here, in order to gradually flow the hydrogen gas in the hydrogen chamber 25 into the hydrogen discharge path 44, the chamber control valve 461 is repeatedly opened and closed.
At time t8, since the pressure in the hydrogen chamber 25 reaches the second pressure value, the chamber control valve 461 is completely closed.

FIG. 4 is a diagram showing the relationship between the pressure in the hydrogen discharge passage and the amount of hydrogen gas that can be stored in the hydrogen chamber.
As shown in FIG. 4, as the pressure in the hydrogen discharge path increases, the amount of hydrogen gas that can be stored in the hydrogen chamber also increases. Therefore, it can be seen that by increasing the pressure in the hydrogen discharge passage, the volume of the hydrogen chamber can be efficiently used to physically store a large amount of hydrogen exhaust gas, and the system can be downsized.

According to this embodiment, there are the following effects.
(1) First, the pressure in the hydrogen chamber 25 is set lower than the pressure in the hydrogen discharge passage 44, and the chamber control valve 25 is opened. Then, the hydrogen exhaust gas in the hydrogen discharge path 44 flows into the hydrogen chamber 25 through the first chamber flow path 46, and at the same time, moisture contained in the hydrogen exhaust gas also flows into the hydrogen chamber 25 due to the pressure pulsation of the hydrogen exhaust gas. . Thereby, the water in the fuel cell 10 and the hydrogen discharge path 44 can be reliably discharged to the hydrogen chamber 25.

  Next, the chamber control valve 461 is closed. Thereby, hydrogen exhaust gas is stored in the hydrogen chamber 25.

  Thereafter, the pressure in the hydrogen chamber 25 is set higher than the pressure in the hydrogen discharge passage 44, and the chamber control valve 461 is opened. Then, the hydrogen exhaust gas in the hydrogen chamber 25 flows into the hydrogen discharge path 44 again. At this time, only water contained in the hydrogen exhaust gas remains in the hydrogen chamber 25. Therefore, since it is not necessary to discharge a large amount of hydrogen exhaust gas at a time in order to discharge moisture as in the prior art, the amount of hydrogen exhaust gas discharged can be reduced.

  Further, when hydrogen exhaust gas is stored in the hydrogen chamber 25, the pressure in the hydrogen chamber 25 can be set to a pressure close to the pressure of the hydrogen discharge passage 44, that is, a somewhat high pressure. By using the volume efficiently, a lot of hydrogen exhaust gas can be physically stored. Therefore, the system can be downsized.

[Second Embodiment]
FIG. 5 is a block diagram of a fuel cell system 1A according to the second embodiment of the present invention.
In the present embodiment, the diluter 23 is not provided, the second chamber flow path 47 is provided, and the configuration of the control device 30A is different from that of the first embodiment.

Specifically, the hydrogen chamber 25 is connected to the air discharge path 42 via the second chamber flow path 47. That is, the second chamber channel 47 communicates the hydrogen chamber 25 and the air discharge path 42. A discharge control valve 471 is provided in the second chamber channel 47. The structure of the discharge control valve 471 is the same as that of the chamber control valve 461.
Further, a concentration sensor 421 that detects the hydrogen concentration is provided on the downstream side of the air discharge passage 42 from the junction with the second chamber passage 47.

The control device 30A includes a second hydrogen exhaust gas processing unit 32 in addition to the first hydrogen exhaust gas processing unit 31, and selectively selects the first hydrogen exhaust gas processing unit 31 or the second hydrogen exhaust gas processing unit 32. To work.
In addition, when operating the 1st hydrogen waste gas processing part 31, it operates with the discharge control valve 471 closed.

The operation of the second hydrogen exhaust gas treatment unit 32 will be described with reference to the flowchart of FIG.
In ST1, the pressure in the hydrogen chamber 25 is set lower than the pressure in the hydrogen discharge path 44, the discharge control valve 471 is closed, and the chamber control valve 461 is opened. Then, since the hydrogen exhaust gas in the hydrogen discharge path 44 flows into the hydrogen chamber 25, the pressure in the hydrogen chamber 25 increases.
In ST2, it is determined whether or not the pressure in the hydrogen chamber 25 has reached the pressure in the hydrogen discharge passage 44. If this determination is NO, the process returns to ST1, and if YES, the process moves to ST3.

In ST3, the chamber control valve 461 is closed.
In ST4, the pressure in the air discharge path 42 is set lower than the pressure in the hydrogen chamber 25, and the discharge control valve 471 is opened. Then, since the hydrogen gas in the hydrogen chamber 25 flows into the air discharge path 42, the pressure in the hydrogen chamber 25 decreases. Here, the opening degree of the discharge control valve 471 is controlled based on the hydrogen concentration detected by the concentration sensor 421.
In ST5, it is determined whether or not the pressure in the hydrogen chamber 25 has reached the pressure value in the air discharge path. If this determination is NO, the process returns to ST4, and if YES, the process proceeds to ST6.
In ST6, the discharge control valve 471 is closed.

According to this embodiment, there are the following effects.
(2) After storing the hydrogen exhaust gas in the hydrogen chamber 25, the pressure in the hydrogen chamber 25 is set higher than the pressure in the air discharge passage 42, the discharge control valve 471 is opened, and the second chamber passage 47 is opened. Then, the hydrogen exhaust gas is gradually discharged to the air discharge path 42. Thereby, since it is not necessary to discharge | emit a lot of hydrogen exhaust gas at once in order to discharge | emit water like the past, the discharge | emission amount of hydrogen exhaust gas can be reduced.
Further, since the hydrogen exhaust gas can be mixed with the oxidant exhaust gas using the pressure difference between the hydrogen exhaust gas and the oxidant exhaust gas, the hydrogen concentration can be easily controlled.

  (3) When opening the discharge control valve 471, the opening degree of the discharge control valve 471 is controlled based on the hydrogen concentration after the hydrogen exhaust gas is mixed with the air exhaust gas. Can accurately control the hydrogen concentration.

Note that the present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the scope in which the object of the present invention can be achieved are included in the present invention.
For example, in the second embodiment of the present invention, when opening the discharge control valve 471, a concentration sensor 421 is provided, and the opening degree of the discharge control valve 471 is controlled based on the hydrogen concentration detected by the concentration sensor 421. However, it is not limited to this.

That is, instead of the concentration sensor 421, a pressure sensor that detects the pressure in the hydrogen chamber and a flow rate sensor that detects the flow rate of the air exhaust gas flowing through the air discharge path 42 are provided, and the hydrogen chamber detected by this pressure sensor The opening degree of the discharge control valve may be controlled based on the internal pressure and the flow rate of the air exhaust gas flowing through the air discharge path 42 detected by the flow sensor.
Even in this case, the hydrogen concentration of the gas discharged to the outside can be accurately controlled.

1 is a block diagram of a fuel cell system according to a first embodiment of the present invention. It is a flowchart of the 1st hydrogen exhaust gas process of the fuel cell system which concerns on the said embodiment. It is a timing chart of the first hydrogen exhaust gas treatment of the fuel cell system according to the embodiment. It is a figure which shows the relationship between the pressure in the hydrogen circulation flow path of the fuel cell system which concerns on the said embodiment, and the amount of hydrogen gas which can be stored in a hydrogen chamber. It is a block diagram of the fuel cell system concerning a 2nd embodiment of the present invention. It is a flowchart of the 2nd hydrogen exhaust gas process of the fuel cell system which concerns on the said embodiment.

Explanation of symbols

1, 1A Fuel cell system 10 Fuel cell 25 Hydrogen chamber 42 Air discharge path (oxidant gas discharge path)
44 Hydrogen discharge passage (hydrogen circulation passage)
46 First chamber flow path 47 Second chamber flow path 461 Chamber control valve 471 Ejection control valve

Claims (6)

A fuel cell that generates electricity by reacting hydrogen gas and oxidant gas; and
A hydrogen circulation passage for supplying hydrogen exhaust gas discharged from the anode side of the fuel cell to the anode side;
An oxidant gas discharge passage for discharging the oxidant exhaust gas discharged from the cathode side of the fuel cell to the outside, a fuel cell system comprising:
A hydrogen chamber;
A first chamber flow path communicating with the hydrogen circulation flow path and the hydrogen chamber and provided with a chamber control valve;
A fuel cell system comprising: a second chamber flow path that communicates the hydrogen chamber and the oxidant gas discharge flow path and is provided with a discharge control valve. A fuel cell that generates electricity by reacting hydrogen gas and oxidant gas, a hydrogen circulation channel that supplies hydrogen exhaust gas discharged from the anode side of the fuel cell to the anode side, and a discharge from the cathode side of the fuel cell A control method for a fuel cell system, comprising: an oxidant gas discharge passage for discharging an oxidant offgas to be discharged to the outside,
A hydrogen chamber, a first chamber channel that communicates with the hydrogen circulation channel and the hydrogen chamber and is provided with a chamber control valve, and a hydrogen chamber and the oxidant gas discharge channel that communicate with each other. A second chamber flow path provided with a valve,
A first step of closing the discharge control valve and opening the chamber control valve;
A second step of closing the chamber control valve when the pressure in the hydrogen chamber reaches a predetermined pressure higher than the pressure of the oxidant discharge channel;
The exhaust control valve is opened, and the hydrogen exhaust gas stored in the hydrogen chamber is discharged to the oxidant gas discharge channel using the pressure difference between the hydrogen chamber and the oxidant gas discharge channel. And a control method for a fuel cell system. In the control method of the fuel cell system according to claim 2,
In the third step, when the discharge control valve is opened, the discharge control valve is based on the hydrogen concentration downstream of the merging point with the second chamber flow path in the oxidant gas discharge flow path. A control method for a fuel cell system, wherein the opening degree of the fuel cell system is controlled. In the control method of the fuel cell system according to claim 2,
In the third step, when opening the discharge control valve, the opening degree of the discharge control valve is set based on the pressure in the hydrogen chamber and the flow rate of the oxidant exhaust gas flowing through the oxidant gas discharge passage. A control method for a fuel cell system, comprising: controlling the fuel cell system. A fuel cell that generates electricity by reacting hydrogen gas and oxidant gas; and
A hydrogen circulation passage for supplying hydrogen exhaust gas discharged from the anode side of the fuel cell to the anode side;
An oxidant gas discharge passage for discharging the oxidant exhaust gas discharged from the cathode side of the fuel cell to the outside, a fuel cell system comprising:
A hydrogen chamber;
A fuel cell system comprising: a first chamber channel that communicates the hydrogen circulation channel and the hydrogen chamber and is provided with a chamber control valve. A fuel cell that generates electricity by reacting hydrogen gas and oxidant gas, a hydrogen circulation channel that supplies hydrogen exhaust gas discharged from the anode side of the fuel cell to the anode side, and a discharge from the cathode side of the fuel cell A control method for a fuel cell system, comprising: an oxidant gas discharge passage for discharging an oxidant offgas to be discharged to the outside,
A hydrogen chamber, a first chamber channel that communicates with the hydrogen circulation channel and the hydrogen chamber and is provided with a chamber control valve, and a hydrogen chamber and the oxidant gas discharge channel that communicate with each other. A second chamber flow path provided with a valve,
A first step of increasing the pressure in the hydrogen circulation path;
A second step of opening the chamber control valve and closing the chamber control valve when the pressure in the hydrogen chamber reaches a first pressure;
A third step of reducing the pressure in the hydrogen circulation path to a second pressure lower than the first pressure;
A fourth step of opening the chamber control valve and closing the chamber control valve when a pressure in the hydrogen chamber reaches a third pressure lower than the first pressure and higher than the second pressure. A control method for a fuel cell system.

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