JP5451248B2 - Stopping storage method of fuel cell system - Google Patents

Description

  The present invention relates to a method for stopping and storing a fuel cell system including a fuel cell configured by providing an electrolyte between an anode supplied with a fuel gas containing hydrogen and a cathode supplied with an oxidant gas.

  At the stage where the stop transition process for shifting the operation of the fuel cell to the stop state where the output of power from the fuel cell is stopped is performed, air (oxygen) as the oxidant gas remains in the cathode. Therefore, as a method for stopping and storing the fuel cell system, for the purpose of preventing deterioration due to oxidation of the cathode, the hydrogen-containing gas is supplied to the cathode, and the stopped state is maintained until the fuel cell is started next time. It has been proposed to perform a stopped state maintaining step (see, for example, Patent Document 1). Specifically, in the method described in Patent Document 1, in a system specially equipped with a gas conduction path connecting the gas flow paths of the anode and the cathode, the hydrogen-containing gas is supplied by supplying the hydrogen-containing gas to the anode. It is also supplied to the cathode through the gas conduction path. Then, after all or part of the oxidant gas remaining on the cathode is replaced with a hydrogen-containing gas, a stop state maintaining step of closing the shutoff valve and sealing the anode and the cathode is performed.

Japanese Patent Laying-Open No. 2005-93115 (Claims 1 to 4)

  In the method described in Patent Document 1, a hydrogen-containing gas is supplied from the anode to the cathode for the purpose of preventing the oxidation of the cathode by the remaining oxidant gas. Therefore, since special piping for supplying the hydrogen-containing gas to the cathode is required, there arises a problem that the configuration of the apparatus becomes complicated and the cost of the apparatus increases. In addition, if a special pipe that is not used during normal power generation operation is used to supply gas that is not used during normal power generation operation to the cathode, complicated procedures such as switching the gas flow path and replacing the gas are required. Is required.

In addition, in the method described in Patent Document 1, the process of supplying the hydrogen-containing gas to the anode and the cathode at an appropriate timing is not performed, but simply the final stage of the stop transition process of the fuel cell system or In the first stage of the stop state maintaining process, the hydrogen-containing gas is sealed in the anode and the cathode only once and left until the next start of the fuel cell system. However, at the stage where the stop transition process is performed, the temperature of the fuel cell is not sufficiently lowered, and a temperature drop may occur in the subsequent stop state maintaining process. Alternatively, even if the temperature of the fuel cell is sufficiently lowered at the stage of performing the stop transition process, the internal temperature of the fuel cell changes according to the temperature change of the environment around the fuel cell during the stop state maintaining process. there's a possibility that. When such a change in internal temperature occurs, the internal pressure of the fuel cell changes. Then, oxygen (air) may enter the anode or cathode inside the fuel cell. Furthermore, oxygen that has entered the cathode may enter the anode through the electrolyte.
Therefore, even if the method described in Patent Document 1 is performed, oxygen may enter the anode during the stop state maintaining step and the anode may be oxidized. The anode is reduced when activated (hydrogen supply) from an oxidized state. However, when this stop and activation (ie, oxidation and reduction) are repeated, the Pt-Ru / C Ru catalyst used as the anode is reduced. The problem of accelerated dissolution has been pointed out. When the dissolution of Ru, which is used for ensuring the resistance of the anode to carbon monoxide poisoning, proceeds, there arises a problem of deterioration of the anode in which the resistance to carbon monoxide poisoning of the anode decreases.
In addition, when hydrogen is supplied to the anode in the presence of oxygen in the anode, the reverse current mechanism works, the carbon used as the cathode electrode material is oxidized, and there is a problem of cathode deterioration that the cathode corrodes. It has been pointed out.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for stopping and storing a fuel cell system capable of maintaining the performance of an anode and a cathode.

In order to achieve the above object, the fuel cell system according to the present invention is characterized in that the storage and storage method includes an electrolyte provided between an anode supplied with a fuel gas containing hydrogen and a cathode supplied with an oxidant gas. A stop storage method for a fuel cell system comprising a fuel cell comprising:
After performing a stop transition process for shifting the operation of the fuel cell to a stop state for stopping the output of power from the fuel cell, at a set timing while performing a stop state maintaining process for maintaining the stop state The hydrogen-containing gas supply process for supplying the hydrogen-containing gas to the anode is performed in a state where the supply of the gas to the cathode is stopped ,
In the stop state maintaining step, the hydrogen-containing gas supply process is performed at the set timing while the anode isolation process is performed to close the gas supply path to the anode and open the gas discharge path from the anode. There is in point to do.

According to the above characteristic configuration, the hydrogen-containing gas supply process for supplying the hydrogen-containing gas to the anode is performed in a state in which the supply of the gas to the cathode is stopped at the set timing during the execution of the stopped state maintaining step. The Here, the setting timing can be set by referring to various values such as pressure and time that can be referred to when operating the fuel cell. For example, it is possible to set the time when the pressure at a certain part reaches the set pressure, or set the time when the elapsed time after starting or ending a certain process reaches the set time. Therefore, when this stopped storage method is carried out, an appropriate timing (set timing) during the stopped state maintaining process is selected and a hydrogen-containing gas is supplied to the anode to increase the pressure of the anode. Even if there is a change in temperature, it is difficult for gas (for example, oxygen) to enter the anode from the outside of the fuel cell or from the cathode. Even if a gas such as oxygen enters the cathode, it reacts with the hydrogen-containing gas supplied to the anode and is consumed. Therefore, since the oxidation of the anode is suppressed, the deterioration of the anode can be suppressed. Further, since the oxidation of the cathode due to the above-described reverse current mechanism is suppressed, the deterioration of the cathode can also be suppressed.
In addition, since no gas is supplied to the cathode, there is no need for a special piping system such as a gas conduction path connecting the gas flow paths of the anode and the cathode, which has been conventionally provided. Therefore, it is possible to avoid the occurrence of the problem that the cost of the apparatus is increased and the problem that a complicated procedure such as switching of the gas flow path and gas replacement is required.
In addition, the gas present in the gas discharge path downstream of the anode is a hydrogen-containing gas that was initially present near the anode. Furthermore, comparing the volume of the gas flow path at the anode with the volume of the gas discharge path downstream of the anode, the volume of the gas discharge path downstream of the anode is generally much larger. Therefore, even if the gas flows backward from the gas discharge path downstream of the anode to the anode, the possibility of causing oxidation of the anode is low. Therefore, the state in which the hydrogen-containing gas exists in the anode can be maintained, and the oxidation of the anode can be suppressed.
Therefore, it is possible to provide a method for stopping and storing the fuel cell system that can maintain the performance of the anode and the cathode.

According to another aspect of the present invention, there is provided a fuel gas generation apparatus for generating the fuel gas supplied to the anode using a reformer in a gas supply path to the anode. Connected,
While the anode isolation process is continuously performed in the stop state maintaining step, when the set timing is reached, the gas supply path to the anode is opened and gas is allowed to flow from the fuel gas generator to the anode. Thus, the hydrogen-containing gas supply process is performed .

  According to the above characteristic configuration, the hydrogen-containing gas supply process in which the gas supply path to the anode is opened and the gas is allowed to flow from the fuel gas generator to the anode is left in the piping upstream of the anode. A gas containing a fuel gas (hydrogen-containing gas) can flow into the anode.
  Further, in order to supply the hydrogen-containing gas to the anode, a special piping system such as a gas conduction path connecting the gas flow paths of the anode and the cathode, which has been conventionally provided, is unnecessary. Therefore, it is possible to avoid the occurrence of the problem that the cost of the apparatus is increased and the problem that a complicated procedure such as switching of the gas flow path and gas replacement is required.

Still another characteristic configuration of the method for stopping and storing a fuel cell system according to the present invention is a fuel configured by providing an electrolyte between an anode supplied with a fuel gas containing hydrogen and a cathode supplied with an oxidant gas. A method for stopping and storing a fuel cell system including a battery,
After performing a stop transition process for shifting the operation of the fuel cell to a stop state for stopping the output of power from the fuel cell, at a set timing while performing a stop state maintaining process for maintaining the stop state The hydrogen-containing gas supply process for supplying the hydrogen-containing gas to the anode is performed in a state where the supply of the gas to the cathode is stopped,
A fuel gas generation device for generating the fuel gas supplied to the anode using a reformer is connected to the gas supply path to the anode,
After starting the stopped state maintaining step, before performing the anode isolation process for closing the gas supply path to the anode and the gas discharge path from the anode in the stopped state maintaining step, or maintaining the stopped state Before performing the anode isolation process for closing the gas supply path to the anode and opening the gas discharge path from the anode in the process, or in the stop state maintaining process, the fuel gas generation device and the anode In a state in which gas flow is permitted, a predetermined portion upstream of the reformer of the gas flow system leading from the fuel gas generation device to the anode is closed and a gas discharge path from the anode is closed Before performing the anode isolation treatment, a predetermined upstream side of the reformer of the gas distribution system leading from the fuel gas generator to the anode The fuel gas generating device isolation process for closing the gas supply passage to the close and and the anode of the position, performed until the temperature of the reformer is below the set temperature,
If the pressure between the predetermined portion and the closed portion of the gas supply path to the anode exceeds the set pressure during the fuel gas generation device isolation process, the gas supply to the predetermined portion and the anode is performed. It is in the point which implements the pressure reduction process which reduces the pressure between the closed parts of a path | route .

  According to the above characteristic configuration, the hydrogen-containing gas supply process for supplying the hydrogen-containing gas to the anode is performed in a state in which the supply of the gas to the cathode is stopped at the set timing during the execution of the stopped state maintaining step. The Here, the setting timing can be set by referring to various values such as pressure and time that can be referred to when operating the fuel cell. For example, it is possible to set the time when the pressure at a certain part reaches the set pressure, or set the time when the elapsed time after starting or ending a certain process reaches the set time. Therefore, when this stopped storage method is carried out, an appropriate timing (set timing) during the stopped state maintaining process is selected and a hydrogen-containing gas is supplied to the anode to increase the pressure of the anode. Even if there is a change in temperature, it is difficult for gas (for example, oxygen) to enter the anode from the outside of the fuel cell or from the cathode. Even if a gas such as oxygen enters the cathode, it reacts with the hydrogen-containing gas supplied to the anode and is consumed. Therefore, since the oxidation of the anode is suppressed, the deterioration of the anode can be suppressed. Further, since the oxidation of the cathode due to the above-described reverse current mechanism is suppressed, the deterioration of the cathode can also be suppressed.
  In addition, since no gas is supplied to the cathode, there is no need for a special piping system such as a gas conduction path connecting the gas flow paths of the anode and the cathode, which has been conventionally provided. Therefore, it is possible to avoid the occurrence of the problem that the cost of the apparatus is increased and the problem that a complicated procedure such as switching of the gas flow path and gas replacement is required.
  In addition, when the temperature of the reformer is still high immediately after the stop transition process of the fuel cell, there is an increase in the reformer pressure due to the generation of hydrogen-containing gas or the generation of steam due to the reforming reaction. Even so, the pressure of the reformer (that is, the pressure in the space between the predetermined portion and the closed portion of the gas supply path to the anode) can be properly maintained by the pressure reduction process.
Therefore, it is possible to provide a method for stopping and storing the fuel cell system that can maintain the performance of the anode and the cathode.

Still another characteristic configuration of the fuel cell system stop storage method according to the present invention is that, in the pressure reduction process, a gas supply path to the anode is opened to release gas from the fuel gas generator to the anode. By flowing in, the pressure between the predetermined portion and the closed portion of the gas supply path to the anode is lowered .

  According to the above characteristic configuration, the pressure reduction process can be performed by opening the closed portion of the gas supply path from the fuel gas generation device to the anode. That is, since a special piping system is not required for performing the pressure reduction process, the fuel cell device configuration is not complicated.

Still another characteristic configuration of the method for stopping and storing a fuel cell system according to the present invention is a fuel configured by providing an electrolyte between an anode supplied with a fuel gas containing hydrogen and a cathode supplied with an oxidant gas. A method for stopping and storing a fuel cell system including a battery,
After performing a stop transition process for shifting the operation of the fuel cell to a stop state for stopping the output of power from the fuel cell, at a set timing while performing a stop state maintaining process for maintaining the stop state The hydrogen-containing gas supply process for supplying the hydrogen-containing gas to the anode is performed in a state where the supply of the gas to the cathode is stopped,
A fuel gas generation device for generating the fuel gas supplied to the anode using a reformer is connected to the gas supply path to the anode,
After starting the stopped state maintaining step, before performing the anode isolation process for closing the gas supply path to the anode and the gas discharge path from the anode in the stopped state maintaining step, or maintaining the stopped state Before performing the anode isolation process for closing the gas supply path to the anode and opening the gas discharge path from the anode in the process, or in the stop state maintaining process, the fuel gas generation device and the anode In a state in which gas flow is permitted, a predetermined portion upstream of the reformer of the gas flow system leading from the fuel gas generation device to the anode is closed and a gas discharge path from the anode is closed Before performing the anode isolation treatment, a predetermined upstream side of the reformer of the gas distribution system leading from the fuel gas generator to the anode The fuel gas generating device isolation process for closing the gas discharge passage from the closing to and the anode of the position, performed until the temperature of the reformer is below the set temperature,
If the pressure between the predetermined part and the closed part of the gas discharge path from the anode exceeds the set pressure while the fuel gas generator isolation process is being performed, gas discharge from the predetermined part and the anode is performed. It is in the point which implements the pressure reduction process which reduces the pressure between the closed parts of a path | route .

According to the above characteristic configuration, the hydrogen-containing gas supply process for supplying the hydrogen-containing gas to the anode is performed in a state in which the supply of the gas to the cathode is stopped at the set timing during the execution of the stopped state maintaining step. The Here, the setting timing can be set by referring to various values such as pressure and time that can be referred to when operating the fuel cell. For example, it is possible to set the time when the pressure at a certain part reaches the set pressure, or set the time when the elapsed time after starting or ending a certain process reaches the set time. Therefore, when this stopped storage method is carried out, an appropriate timing (set timing) during the stopped state maintaining process is selected and a hydrogen-containing gas is supplied to the anode to increase the pressure of the anode. Even if there is a change in temperature, it is difficult for gas (for example, oxygen) to enter the anode from the outside of the fuel cell or from the cathode. Even if a gas such as oxygen enters the cathode, it reacts with the hydrogen-containing gas supplied to the anode and is consumed. Therefore, since the oxidation of the anode is suppressed, the deterioration of the anode can be suppressed. Further, since the oxidation of the cathode due to the above-described reverse current mechanism is suppressed, the deterioration of the cathode can also be suppressed.
  In addition, since no gas is supplied to the cathode, there is no need for a special piping system such as a gas conduction path connecting the gas flow paths of the anode and the cathode, which has been conventionally provided. Therefore, it is possible to avoid the occurrence of the problem that the cost of the apparatus is increased and the problem that a complicated procedure such as switching of the gas flow path and gas replacement is required.
  In addition, when the temperature of the reformer is still high after starting the fuel cell stop state maintaining step, the predetermined portion and the anode are generated by the generation of hydrogen-containing gas or the generation of water vapor by the reforming reaction. Even if there is an increase in pressure between the gas discharge path and the closed portion of the gas discharge path (that is, the pressure in the space including the reformer and the anode as a whole), the pressure can be properly maintained by the pressure reduction process. it can.
  Furthermore, since the anode is supplied with a hydrogen-containing gas containing hydrogen generated in the reformer while the pressure between the predetermined portion and the closed portion of the gas discharge path from the anode is increased, the oxidant gas is supplied. Even if it flows into the cathode, it reacts with the hydrogen-containing gas flowing into the anode and is easily consumed. As a result, it is possible to suppress the oxidant gas from entering the anode through the electrolyte from the cathode.
Therefore, it is possible to provide a method for stopping and storing the fuel cell system that can maintain the performance of the anode and the cathode.

Still another characteristic configuration of the method for stopping and storing the fuel cell system according to the present invention is that the gas discharge from the predetermined portion and the anode is performed by opening a closed portion of the gas discharge path from the anode in the pressure reduction process. It is in the point which reduces the pressure between the closed parts of a path .

  According to the above characteristic configuration, the pressure reduction process can be performed by opening the closed portion of the gas discharge path from the anode. That is, since a special piping system is not required for performing the pressure reduction process, the fuel cell device configuration is not complicated.

Still another characteristic configuration of the fuel cell system stop storage method according to the present invention is that the anode isolation process closes the gas supply path to the anode and the gas discharge path from the anode in the stop state maintaining step. The hydrogen-containing gas supply process is performed at the set timing while the anode isolation process is being performed .

According to the above characteristic configuration, since the anode isolation process is performed to close the gas supply path to the anode and the gas discharge path from the anode, it is possible to reliably hold the anode with the supplied hydrogen-containing gas.

Still another characteristic configuration of the fuel cell system stop storage method according to the present invention is that the anode isolating process closes the gas supply path to the anode and stops the gas discharge path from the anode in the stop state maintaining step. The hydrogen-containing gas supply process is performed at the set timing while the anode isolation process is performed .

According to the above characteristic configuration, the gas present in the gas discharge path on the downstream side of the anode is a hydrogen-containing gas originally present in the vicinity of the anode. Furthermore, comparing the volume of the gas flow path at the anode with the volume of the gas discharge path downstream of the anode, the volume of the gas discharge path downstream of the anode is generally much larger. Therefore, even if the gas flows backward from the gas discharge path downstream of the anode to the anode, the possibility of causing oxidation of the anode is low. Therefore, the state in which the hydrogen-containing gas exists in the anode can be maintained, and the oxidation of the anode can be suppressed.

Still another characteristic configuration of the fuel cell system stop storage method according to the present invention is that, when the anode isolation process is continuously performed in the stop state maintaining step, the gas to the anode is reached at the set timing. The hydrogen-containing gas supply process is performed by opening a supply path and allowing gas to flow from the fuel gas generator to the anode .

According to the above characteristic configuration, the hydrogen-containing gas supply process in which the gas supply path to the anode is opened and the gas is allowed to flow from the fuel gas generator to the anode is left in the piping upstream of the anode. A gas containing a fuel gas (hydrogen-containing gas) can flow into the anode.
Further, in order to supply the hydrogen-containing gas to the anode, a special piping system such as a gas conduction path connecting the gas flow paths of the anode and the cathode, which has been conventionally provided, is unnecessary. Therefore, it is possible to avoid the occurrence of the problem that the cost of the apparatus is increased and the problem that a complicated procedure such as switching of the gas flow path and gas replacement is required.

According to still another feature of the fuel cell system stop storage method according to the present invention, the anode isolation process allows gas flow between the fuel gas generation device and the anode in the stop state maintaining step. In this state, it is carried out by closing the predetermined part upstream of the reformer of the gas distribution system leading from the fuel gas generating device to the anode and closing the gas discharge path from the anode,
The hydrogen-containing gas supply process is performed at the set timing while the anode isolation process is being performed .

According to the above characteristic configuration, the pressure from the upstream side of the reformer of the fuel gas generation device to the anode can be integrally held. While the pressure is maintained, gas may flow from the fuel gas generator to the anode, but it is hydrogen-containing gas that exists upstream of the anode. Therefore, the oxidation of the anode can be suppressed.

Still another characteristic configuration of the fuel cell system stop storage method according to the present invention is that the predetermined portion is opened at the set timing while the anode isolation process is continuously performed in the stop state maintaining step. Thus, the hydrogen-containing gas supply process is performed by flowing a gas from the fuel gas generator to the anode .

According to the above characteristic configuration, the fuel gas that has remained in the pipe upstream of the anode is obtained by performing the hydrogen-containing gas supply process in which the predetermined portion is opened and gas flows into the anode from the fuel gas generator. A gas containing (hydrogen-containing gas) can flow into the anode.
Further, in order to supply the hydrogen-containing gas to the anode, a special piping system such as a gas conduction path connecting the gas flow paths of the anode and the cathode, which has been conventionally provided, is unnecessary. Therefore, it is possible to avoid the occurrence of the problem that the cost of the apparatus is increased and the problem that a complicated procedure such as switching of the gas flow path and gas replacement is required.

Still another characteristic configuration of the method for stopping and storing the fuel cell system according to the present invention is that the hydrogen-containing gas supply process is repeatedly performed at a plurality of the set timings .

According to the above characteristic configuration , the hydrogen-containing gas supply process is repeatedly performed at a plurality of suitable timings (setting timings) in the stopped state maintaining step, so that the performance of the anode and the cathode is maintained over a long period of time during the stopped state maintaining step. Can be reliably maintained.

Still another characteristic configuration of the method for stopping and storing the fuel cell system according to the present invention is that the hydrogen-containing gas supply process is stopped after the hydrogen-containing gas supply process is performed for a predetermined period .

According to the above characteristic configuration, it is possible to prevent oxygen from flowing into the anode by performing the hydrogen-containing gas supply process for a predetermined period of time, and by stopping the hydrogen-containing gas supply process, the anode is maintained in the stopped state maintaining step. The amount of gas used to supply the hydrogen-containing gas can be suppressed. Therefore, the energy used for carrying out the stop storage method of the fuel cell system can be saved.

Still another characteristic configuration of the method for stopping and storing the fuel cell system according to the present invention is that the time from the start of the stopped state maintaining step reaches a predetermined time, or the temperature of the anode or the anode The hydrogen-containing gas supply process is carried out for a predetermined period when the temperature of the reformer of the fuel gas generation apparatus connected to the gas supply path for generating the fuel gas supplied to the anode decreases to a predetermined temperature. It is in the point to judge .

According to the above characteristic configuration, it is possible to determine that the predetermined period has been reached by referring to the time from the start of the stopped state maintaining step or referring to the temperature of the anode or the temperature of the reformer.

According to still another aspect of the present invention, there is provided a fuel gas generation apparatus for generating the fuel gas supplied to the anode in a gas supply path to the anode using a reformer. Is connected,
After stopping the hydrogen-containing gas supply processing, the gas supply path to the anode and the gas discharge path from the anode are closed, the gas supply path to the anode is closed, and the gas discharge path from the anode Or in a state where gas flow between the fuel gas generation device and the anode is permitted, upstream of the reformer of the gas flow system that leads from the fuel gas generation device to the anode. The fuel cell is stored in a form in which a predetermined portion on the side is closed and a gas discharge path from the anode is closed .

According to the above characteristic configuration, after stopping the hydrogen-containing gas supply process, the fuel cell can be stored in a form in which gas does not easily enter the anode.

It is a figure explaining the structure of the fuel cell system with which the stop storage method of a fuel cell system is implemented. It is a figure explaining another structure of the fuel cell system with which the stop storage method of a fuel cell system is implemented. It is a figure explaining another structure of the fuel cell system with which the stop storage method of a fuel cell system is implemented. It is a figure explaining another structure of the fuel cell system with which the stop storage method of a fuel cell system is implemented. It is a timing diagram explaining the operating state of a fuel cell system.

<First Embodiment>
Hereinafter, a method for stopping and storing the fuel cell system according to the first embodiment will be described with reference to the drawings. This stop storage method is a method of performing a stop state maintaining process described below.
FIG. 1 is a diagram illustrating a configuration of a fuel cell system S1 in which a method for stopping and storing a fuel cell system is implemented. The fuel cell system S1 includes a fuel gas generation device 1 and a fuel cell FC. The operation control of the fuel cell system S1 to be described later is performed by the control means C unless otherwise specified. The fuel gas generator 1 steam-reforms a raw fuel gas containing a hydrocarbon such as methane in a reformer 1a to generate a fuel gas containing hydrogen as a main component. In addition to the reformer 1a shown in FIG. 1, the fuel gas generator 1 includes a desulfurizer, a steam generator, and a gas obtained by steam reforming for removing sulfur compounds contained in the raw material gas. The carbon monoxide remover etc. which remove the carbon monoxide contained in are provided, but those descriptions are omitted. The reformer 1a is provided with a pressure sensor P1 for detecting the pressure of the reformer 1a and a temperature sensor T1 for detecting the temperature of the reformer 1a.
The gas discharged from the fuel gas generator 1 is supplied to the anode 2a via the gas supply path 3, or is discharged to the outside via the pressure release path.

  The fuel cell FC includes a cell 2 that generates power. The cell 2 is configured by providing an electrolyte 2c between an anode 2a to which a fuel gas containing hydrogen is supplied and a cathode 2b to which an oxidant gas is supplied. A fuel gas generator 1 is connected to the gas supply path 3 to the anode 2a. The fuel gas generated by the fuel gas generation device 1 is supplied via the gas supply path 3. The anode 2a is provided with a pressure sensor P2 for detecting the pressure of the anode 2a and a temperature sensor T2 for detecting the temperature of the anode 2a.

In the middle of the gas supply path 3 to the anode 2a, a fuel gas humidifier 4 having a fuel gas storage water tank 4a is provided. In the fuel gas humidifier 4, the fuel gas is supplied from the fuel gas generating device 1 through the gas supply path 3 into the stored water stored in the fuel gas storage water tank 4 a and is supplied to the surface of the stored water. While coming out, humidify the fuel gas in contact with the stored water. The space on the surface of the stored water inside the fuel gas storage water tank 4a is connected to the anode 2a. In the middle of the gas supply path 3 from the fuel gas generating device 1 to the anode 2a, a valve V2 for blocking or allowing the gas flow in the gas supply path 3 is provided.
The gas used for the power generation reaction in the anode 2a is discharged to the outside of the fuel cell FC through the gas discharge path 7. The exhausted gas is recovered in exhaust heat in a heat exchanger (not shown) and then provided to an exhaust process such as burning in a burner (not shown). In the middle of the gas discharge path 7, a valve V <b> 3 that blocks or allows the gas flow in the gas discharge path 7 is provided.

Air as an oxidant gas is supplied to the cathode 2 b through the gas supply path 5 by the blower 9. In the middle of the gas supply path 5, an oxidant gas humidifier 6 having an oxidant gas storage water tank 6a is provided. The oxidant gas humidifier 6 is configured such that the air supplied from the blower 9 is supplied to the stored water stored in the oxidant gas storage water tank 6a through the gas supply path 5, and the surface of the stored water. While coming out, the oxidant gas is brought into contact with the stored water and humidified. The space on the surface of the stored water inside the oxidant gas storage water tank 6a is connected to the cathode 2b. In the middle of the gas supply path 5 from the blower 9 to the cathode 2b, a valve V4 for blocking or allowing the gas flow in the gas supply path 5 is provided.
The gas used for the power generation reaction at the cathode 2b is discharged to the outside of the fuel cell FC via the gas discharge path 8. The exhausted gas is recovered as exhaust heat by a heat exchanger (not shown). Since the exhausted gas is originally air present in the surroundings, no special exhaust treatment is required.

Below, the operation process of the fuel cell FC (during power generation), the stop transition process for shifting the operation of the fuel cell FC to a stop state in which the output of power from the fuel cell FC is stopped, and the stop after the stop transition process Each of the stop state maintaining steps for maintaining the state will be described with reference to a timing diagram illustrating the operating state of the fuel cell system S1 shown in FIG. In FIG. 5, the reforming catalyst temperature (° C.) is represented by a numerical value on the vertical axis, the value obtained by multiplying the battery temperature (° C.) by 10 is represented by the numerical value on the vertical axis, and the cathode air flow rate (l / min) is multiplied by 10 times. The value obtained by multiplying the cell voltage (V) by 10 is represented by the value on the vertical axis, and the value obtained by multiplying the raw material gas flow rate (l / min) by 10 ² is represented by the value on the vertical axis. A value obtained by multiplying the reformer pressure (kPa) by 10 is represented by a numerical value on the vertical axis.

[Operation process (during power generation)]
When the power generation operation of the fuel cell FC is performed, the fuel gas generation device 1 also needs to be operated. Therefore, the valve V1 is opened so that the raw material gas can be supplied to the fuel gas generator 1. In the reformer 1a, a reforming reaction for reforming the hydrocarbon, which is the raw material gas, into hydrogen is performed, thereby generating a fuel gas containing hydrogen. The valve V2 provided in the gas supply path 3 is opened, and the valve 5 provided in the pressure release path 15 is closed. Therefore, the fuel gas generated by the fuel gas generation device 1 is supplied to the anode 2 a via the fuel gas humidifier 4. The valve V3 is opened, and the exhaust gas from the anode 2a is discharged outside the fuel cell FC.
The valve V4 provided in the gas supply path 5 is opened so that the air (oxidant gas) supplied by the blower 9 reaches the cathode 2b.
Although not shown, an electric load or an inverter is electrically connected to the cell 2.
As described above, fuel gas is supplied to the anode 2a and air is supplied to the cathode 2b, whereby a power generation reaction is performed in the cell 2 and a current flows through the electric load or the inverter.

[Stop transition process]
The stop transition process of stopping the operation of the fuel cell FC releases the electrical connection between the electric load or the inverter and the cell 2 of the fuel cell FC, and stops the output of the power obtained by the power generation in the fuel cell FC. It is a process to do. Therefore, before the output of the electric power obtained by the power generation in the fuel cell FC is stopped, the supply amount of the raw material gas and the supply amount of the oxidant gas (cathode air) to the fuel cell FC are decreased. As a result, the amount of gas (including water vapor) generated inside the reformer 1a decreases, and the pressure of the reformer 1a also decreases. Further, the temperature of the fuel cell FC (that is, the temperature of the anode 2a and the cathode 2b) gradually decreases.

  Thereafter, the blower 9 is stopped, the valve V4 provided in the gas supply path 5 to the cathode 2b is closed, and the supply of air to the cathode 2b is stopped. At this time, the raw material gas is supplied to the fuel gas generator 1, and the supply of the fuel gas from the fuel gas generator 1 to the anode 2a is continued. Therefore, in the cell 2, the supply amount of air is very small compared to the supply amount of fuel gas, and the cell voltage is rapidly reduced. That is, here, the air (oxygen) remaining on the cathode 2b reacts with the fuel gas (hydrogen) remaining on the anode 2a in a state where the supply of air to the cathode 2b is stopped. Then, the electrical connection between the electric load or the inverter and the cell 2 of the fuel cell FC is released, and the output of the electric power obtained by the power generation in the fuel cell FC is stopped.

[Stop state maintenance process]
In the stopped state maintaining step of maintaining the stopped state of the fuel cell FC, the hydrogen-containing gas supply for supplying the hydrogen-containing gas to the anode 2a at the set timing during the stop state maintaining step in the stopped storage method according to the present application. The treatment is performed in a state where the supply of gas to the cathode 2b is stopped. In the present embodiment, no gas is supplied to the cathode 2b in the stopped state maintaining step. The hydrogen-containing gas supply process is performed at a set timing during the anode isolation process for closing the gas supply path 3 to the anode 2a and the gas discharge path 7 from the anode 2a. That is, the anode isolation process is performed by closing the valve V2 and the valve V3.

  However, as shown in FIG. 5, the temperature of the reforming catalyst inside the reformer 1a has not yet decreased at the time when the stop transition process is completed, and generation of hydrogen-containing gas or generation of water vapor by the reforming reaction. The pressure of the reformer 1a is increased due to the above. Therefore, when the valve V2 is opened while the temperature of the reforming catalyst is high, the gas or water vapor is supplied to the anode 2a, the pressure of the anode 2a increases, and the cathode 2b in which the supply of air is stopped There is a possibility that the pressure difference will increase and the electrolyte 2c may be damaged. Therefore, until the temperature of the reforming catalyst becomes equal to or lower than the set temperature (650 ° C. in the example shown in FIG. 5), the valve V1 (“upstream side of the reformer of the gas distribution system leading from the fuel gas generating device to the anode of the present invention” The fuel gas generator isolating process for closing the valve V2 (an example of the "closing part of the gas supply path to the anode" of the present invention) of the present invention is performed before the anode isolating process. To do. However, the “predetermined portion upstream of the reformer of the gas distribution system leading from the fuel gas generating device to the anode” is a portion of the valve V1 for supplying or stopping the raw material gas to the fuel gas generating device 1. However, the predetermined part can be appropriately changed as long as it is a part upstream of the reformer 1a inside the fuel gas generator 1.

  While the fuel gas generator isolating process is being performed, an increase in the pressure of the reformer 1a due to the generation of hydrogen-containing gas by the reforming reaction or the generation of water vapor is observed. Therefore, when the pressure between the valve V1 and the valve V2 exceeds the set pressure, a pressure reduction process for reducing the pressure between the valve V1 and the valve V2 is performed. Specifically, when the pressure of the reformer 1a existing between the valve V1 and the valve V2 exceeds a set pressure (10 kPa in the example shown in FIG. 5), the valve V5 provided in the pressure release path is temporarily To open. As a result, the pressure between the valve V1 and the valve V2 decreases. As shown in FIG. 5, the temperature of the reforming catalyst gradually decreases while the pressure reduction process repeatedly increases and decreases the pressure of the reformer 1 a (described as “pressure release process” in FIG. 5). To do. When the temperature of the reformer 1a (that is, the temperature of the reforming catalyst) becomes equal to or lower than the set temperature (250 ° C. in the example shown in FIG. 5), the fuel gas generator isolation process is terminated.

  After the fuel gas generator isolating process is completed, the pressure increase in the reformer 1a is not observed, and conversely, the pressure decrease due to the temperature decrease of the reforming catalyst is observed. Therefore, the valve V1 is opened with the valve V2 and the valve V5 closed, and the raw material gas is caused to flow into the fuel gas generator 1 to increase the pressure of the reformer 1a to, for example, 6 kPa or more. However, since the temperature of the fuel gas generator 1 (and the reformer 1a) decreases, the pressure of the reformer 1a gradually decreases and may become less than a specified pressure (for example, 1 kPa). In that case, the valve V1 is opened again, and the raw material gas is caused to flow into the fuel gas generator 1 so that the pressure in the reformer 1a becomes equal to or higher than the specified pressure. As a result, as shown in FIG. 5, the pressure of the reformer 1 a is reduced due to the temperature drop of the fuel gas generator 1 (and the reformer 1 a), and the valve V <b> 1 is opened to feed the raw material gas. The pressure increase due to the above is repeated (described as “pressure maintenance process” in FIG. 5).

  After the above-described fuel gas generation device isolation process, the valve V2 is opened and the fuel gas generation device 1 is opened at the set timing while the anode isolation processing in which the valve V2 and the valve V3 are closed is continued. A hydrogen-containing gas supply process is performed (started) by flowing a gas into the anode 2a. In other words, by opening the valve V2 at a set timing while the anode isolation process in which the valve V2 and the valve V3 are closed is continuously performed (that is, the anode isolation state in which the anode isolation process is being performed) The hydrogen-containing gas supply process is performed (by opening the valve V2 temporarily to release the valve V2), and then the anode isolation process is performed to reset the anode isolation state again. When gas flows into the anode 2a from the fuel gas generator 1, the fuel gas (hydrogen-containing gas) remaining in the pipe on the upstream side of the anode 2a flows into the anode 2a.

In the present embodiment, as shown in FIG. 5, the pressure of the reformer 1a (an example of a “predetermined part of the gas distribution system leading to the anode 2a inside the fuel gas generating device 1)” is the fuel gas generating device 1 ( And while the pressure drop due to the temperature drop of the reformer 1a) and the pressure rise by opening the valve V1 and flowing the raw material gas are repeated, the pressure of the reformer 1a tends to drop When the predetermined pressure is reached (4 kPa in the example shown in FIG. 5), it is determined that the set timing is reached. Then, the valve V2 is opened for a set time, and the hydrogen-containing gas is allowed to flow into the anode 2a during that time. That is, the hydrogen-containing gas supply process is repeatedly performed at a plurality of appropriate setting timings. As a result, the pressure of the anode 2a can be maintained with the hydrogen-containing gas, so that intrusion of air from the outside to the anode 2a can be suppressed, and even if there is intrusion of oxygen from the cathode 2b to the anode 2a. Since the invading oxygen is consumed by reacting with the hydrogen-containing gas supplied to the anode 2a and the oxygen concentration is lowered, it can be suppressed that the anode 2a is oxidized by the oxygen.
Note that if the process of opening the valve V2 for a set time is performed, the pressure in the reformer 1a suddenly decreases. Therefore, the valve V1 is opened again, the raw material gas is allowed to flow into the fuel gas generator 1, and the reforming is performed. The pressure of the mass device 1a is set to a specified pressure or higher.

  After performing the hydrogen-containing gas supply process for a predetermined period, the hydrogen-containing gas supply process is stopped. For example, when the time from the start of the stopped state maintaining process reaches a predetermined time (for example, 24 hours), or the temperature of the anode 2a is decreased to a predetermined temperature (for example, outside air temperature + 5 ° C.). It is determined that the hydrogen-containing gas supply process has been performed for a predetermined period. Then, after stopping the hydrogen-containing gas supply process, the gas supply path 3 to the anode 2a and the gas discharge path 7 from the anode 2a are closed, the gas supply path 3 to the anode 2a is closed, and the anode 2a The gas discharge path 7 is opened, or in a state in which the gas flow between the fuel gas generating device 1 and the anode 2a is allowed, the gas distribution system leading to the anode 2a inside the fuel gas generating device 1 The fuel cell FC is stored in a form in which a predetermined portion is closed and the gas discharge path 7 from the anode 2a is closed.

  As described above, by supplying the hydrogen-containing gas to the anode 2a and increasing the pressure of the anode 2a, it becomes difficult for gas (for example, oxygen) to enter the anode 2a from the outside (for example, the cathode 2b). Therefore, since the oxidation of the anode 2a is suppressed, the deterioration of the anode 2a can be suppressed. Further, since the oxidation of the cathode 2b by the reverse current mechanism described as the problem is also suppressed, the deterioration of the cathode 2b can be suppressed.

Second Embodiment
The fuel cell system stop storage method of the second embodiment differs from the first embodiment in the content of the anode isolation process. The fuel cell system stop storage method of the second embodiment will be described below, but the description of the same features as those of the first embodiment will be omitted.

  In this embodiment, in the stop state maintaining step, the anode isolation process is performed in which the gas supply path 3 to the anode 2a is closed by closing the valve V2 and the gas discharge path 7 from the anode 2a is opened. The hydrogen-containing gas supply process is performed by opening the valve V2 at the set timing. Specifically, the anode isolation process is performed by closing the valve V2, and at this time, the valve V3 is open. For example, since the valve V3 is opened in the stop transition process, the valve V3 may be maintained in the open state when the process proceeds to the stop state maintaining process. Alternatively, the valve V3 is closed until the fuel gas generating device isolation process in which the pressure reduction process is performed after the process proceeds to the stop state maintaining process, and then the valve V3 is turned on at the timing when the anode isolation process is started. Open it. The valve V2 is opened at a set timing while the anode isolation process with the valve V2 closed is continuously performed (that is, the isolation state of the anode performing the anode isolation process is changed to the valve V2). A hydrogen-containing gas supply process is performed (by opening and releasing temporarily), and then an anode isolation process is performed to set the anode isolation state again.

<Third Embodiment>
The fuel cell system stop storage method of the third embodiment differs from the first and second embodiments in the contents of the anode isolation process and the hydrogen-containing gas supply process. The fuel cell system stop storage method of the third embodiment will be described below, but the description of the same features as those of the first embodiment will be omitted.

  In the present embodiment, in the stopped state maintaining step, a predetermined gas distribution system leading to the anode 2a inside the fuel gas generation device 1 in a state where the gas flow between the fuel gas generation device 1 and the anode 2a is allowed. The hydrogen-containing gas supply process is performed at a set timing while the anode isolation process for closing the portion and closing the gas discharge path 7 from the anode 2a is performed. Specifically, in the stopped state maintaining step, the valve V2 is opened to allow gas flow between the fuel gas generating device 1 and the anode 2a, and the valve V1 and the valve V3 are closed to generate fuel gas. An anode isolation process for closing the apparatus 1 to the gas discharge path 7 of the anode 2a is performed. Then, while the anode isolation process is continuously performed, when the set timing is reached, the valve V1 is opened and the raw material gas flows into the fuel gas generator 1. In other words, by opening the valve V1 at a set timing while the anode isolation process in which the valve V1 and the valve V3 are closed is continuously performed (ie, the isolation state of the anode in which the anode isolation process is being performed) The hydrogen-containing gas supply process is performed (by opening the valve V1 temporarily to release the valve V1), and then the anode isolation process is performed to set the anode isolation state again. By flowing the gas from the fuel gas generating device 1 to the anode 2a, a hydrogen-containing gas supply process is performed in which the hydrogen-containing gas remaining on the upstream side of the anode 2a is supplied to the anode 2a.

<Fourth embodiment>
The fuel cell system stop storage method of the fourth embodiment differs from the first to third embodiments in the configuration of the fuel cell system. The fuel cell system stop storage method of the fourth embodiment will be described below, but the description of the same features as those of the first to third embodiments will be omitted.

  FIG. 2 is a diagram illustrating the configuration of the fuel cell system S2 in which the method for stopping and storing the fuel cell system is implemented. The fuel cell system S2 shown in FIG. 2 is not provided with the pressure release path and the valve V5 provided in the fuel cell system S1 shown in FIG. Therefore, the content of the pressure reduction process while the fuel gas generation device isolation process is being performed is different from that of the first to third embodiments.

As described in the first embodiment, in the fuel cell system S2 shown in FIG. 2, the hydrogen-containing gas is generated by the reforming reaction or the water vapor is generated while the fuel gas generator isolating process is being performed. An increase in the pressure of the reformer 1a is observed. Therefore, when the pressure between the valve V1 and the valve V2 exceeds the set pressure, a pressure reduction process for reducing the pressure between the valve V1 and the valve V2 is performed. Specifically, when the pressure of the reformer 1a existing between the valve V1 and the valve V2 exceeds a set pressure (for example, 6 kPa), the valve V2 (the “closing portion of the gas supply path to the anode of the present invention”). ) Is opened and gas is allowed to flow from the fuel gas generator 1 to the anode 2a, so that the valve V1 and the valve V2 are separated (the "predetermined portion and the closed portion of the gas supply path to the anode of the present invention). Decrease the pressure of “example”.
Therefore, by this pressure reduction process, the pressure between the valve V1 and the valve V2 can be reduced, and the hydrogen-containing gas can flow into the anode 2a. That is, this pressure reduction process can also be regarded as a hydrogen-containing gas supply process.

< Other embodiments>
Stop storage method of a fuel cell system according to another embodiment, the configuration of the first to fourth embodiments and the fuel cell system is different. The fuel cell system suspension and storage method of another embodiment will be described below, but the description of the same features as those of the first to fourth embodiments will be omitted.

FIG. 3 is a diagram illustrating a configuration of a fuel cell system S3 in which the stop storage method for the fuel cell system according to another embodiment is implemented. As shown in FIG. 3, the fuel cell FC includes a fuel gas humidifier 4, an oxidant gas humidifier 6, and a water amount regulator 10. The fuel gas humidifier 4 has a fuel gas storage water tank 4a provided in the middle of the gas supply path 3 to the anode 2a, and the stored water in which the fuel gas is stored in the fuel gas storage water tank 4a. Fuel gas is brought into contact with the stored water and humidified while it is supplied inside and comes out to the surface of the stored water. The oxidant gas humidifier 6 has an oxidant gas storage water tank 6a provided in the middle of the gas supply path 5 to the cathode 2b, and the oxidant gas is stored in the oxidant gas storage water tank 6a. While being supplied into the stored water and coming out to the surface of the stored water, the oxidizing gas is brought into contact with the stored water and humidified. The water amount adjuster 10 includes a water level adjusting tank 12 for storing stored water supplied to the fuel gas storage water tank 4a and the oxidant gas storage water tank 6a, the fuel gas storage water tank 4a and the oxidant gas storage. The water level control part 11 which adjusts the water level of the stored water in the stored water tank 6a is provided. The water level adjustment tank 12 and the fuel gas storage water tank 4a are connected by a flow path 13, and the water level adjustment tank 12 and the oxidant gas storage water tank 6a are connected by a flow path 14.
Further, in the fuel cell FC shown in FIG. 3, no valve is provided in the gas supply path 5 to the cathode 2b, and the stored water stored in the oxidant gas storage water tank 6a is supplied to the cathode 2b. It becomes a valve for (oxidant gas).

The water level adjuster 10 operates in the stopped state maintaining step to increase the amount of stored water stored in the oxidant gas storage water tank 6a. As a result, the volume from the cathode 2b to the water surface of the oxidant gas storage water tank 6a upstream is reduced. That is, the amount of air that can flow into the cathode 2b after the blower 9 is stopped can be reduced. As a result, the amount of oxygen entering the anode 2a from the cathode 2b via the electrolyte is reduced.
Further, the water level adjuster 10 operates in the stop state maintaining step to reduce the amount of stored water stored in the fuel gas storage water tank 4a. As a result, the volume from the anode 2a to the water surface of the upstream side fuel gas storage water tank 4a increases. That is, since more hydrogen-containing gas can remain on the upstream side of the anode 2a, more hydrogen-containing gas can flow into the anode 2a in the hydrogen-containing gas supply process.
As described above, the water level adjuster 10 increases the amount of stored water stored in the oxidant gas storage water tank 6a on the one hand and decreases the amount of stored water stored in the fuel gas storage water tank 4a on the other hand. Therefore, by operating the water level regulator 10 and moving the stored water from the fuel gas storage water tank 4a to the oxidant gas storage water tank 6a, the amount of stored water stored in the oxidant gas storage water tank 6a is increased. And the amount of stored water stored in the fuel gas storage water tank 4a can be reduced.
The water level adjustment described above is preferably performed prior to the start of the stopped state maintaining step. Further, the water amount adjuster 10 performs only one of the process of increasing the amount of stored water stored in the oxidant gas storage water tank 6a and the process of decreasing the amount of stored water stored in the fuel gas storage water tank 4a. You may go.

< Another embodiment>
Stop storage method of the fuel cell system of another alternative embodiment, the arrangement of the another embodiment and the fuel cell system is different. Hereinafter, a method for stopping and storing a fuel cell system according to another embodiment will be described, but description of features similar to those of the other embodiments will be omitted.

FIG. 4 is a diagram for explaining the configuration of a fuel cell system S4 in which a method for stopping and storing a fuel cell system according to another embodiment is implemented. As shown in FIG. 4, in this embodiment, the level wall 4b that can detect whether or not the stored water is equal to or higher than the maximum water level is provided on the inner side wall of the fuel gas storage water tank 4a, and the stored water is the lowest. A level sensor 4c capable of detecting whether or not the water level is below is provided. Similarly, on the inner side wall of the oxidant gas storage water tank 6a, a level sensor 6b that can detect whether or not the stored water is at or above the maximum water level, and whether or not the stored water is below the minimum water level. A level sensor 6c that can be detected is provided.

During the power generation of the fuel cell FC, the water amount regulator 10 is configured so that the water level of the stored water in the fuel gas storage water tank 4a and the oxidant gas storage water tank 6a is between the above-described maximum water level and minimum water level. It is adjusting.
On the other hand, the water amount adjuster 10 operates in the stop state maintaining step to increase the amount of stored water stored in the oxidant gas storage water tank 6a. For example, the amount of stored water stored in the oxidant gas storage water tank 6a is adjusted to the maximum water level. As a result, the volume from the cathode 2b to the water surface of the oxidant gas storage water tank 6a upstream is reduced. That is, the amount of air that can flow into the cathode 2b after the blower 9 is stopped can be reduced. As a result, the amount of oxygen entering the anode 2a from the cathode 2b via the electrolyte is reduced.
Further, the water amount adjuster 10 operates in the stop state maintaining step to reduce the amount of stored water stored in the fuel gas storage water tank 4a. For example, the amount of stored water stored in the fuel gas storage water tank 4a is adjusted to the minimum water level. As a result, the volume from the anode 2a to the water surface of the upstream side fuel gas storage water tank 4a increases. That is, since more hydrogen-containing gas can remain on the upstream side of the anode 2a, more hydrogen-containing gas can flow into the anode 2a in the hydrogen-containing gas supply process.
As described above, the water amount adjuster 10 increases the amount of water stored in the oxidant gas storage water tank 6a on the one hand, and decreases the amount of water stored in the fuel gas storage water tank 4a on the other hand. Therefore, the amount of stored water stored in the oxidant gas storage water tank 6a is increased by operating the water amount regulator 10 to move the stored water from the fuel gas storage water tank 4a to the oxidant gas storage water tank 6a. And the amount of stored water stored in the fuel gas storage water tank 4a can be reduced.
The water level adjustment described above may be performed not in the stop state maintaining step but in the stop transition step. Further, the water amount adjuster 10 performs only one of the process of increasing the amount of stored water stored in the oxidant gas storage water tank 6a and the process of decreasing the amount of stored water stored in the fuel gas storage water tank 4a. You may go.

<Another embodiment>
<1>
In the above embodiment, the setting timing for supplying the hydrogen-containing gas to the anode 2a in the hydrogen-containing gas supply process is exemplified by the timing when the pressure of the reformer 1a becomes the setting pressure when the pressure tends to decrease. The timing can also be set as the set timing. For example, the elapsed time after the end of the fuel gas generating device isolation process is measured, and every time the elapsed time reaches a set time (for example, the elapsed time after the end of the fuel gas generating device isolation process is 10 minutes, It may be determined that the set timing has been reached (every 30 minutes, 60 minutes, 120 minutes, ...).

<2>
In the above embodiment, if it is not necessary to detect the pressure and temperature of the anode 2a, the pressure sensor P2 for detecting the pressure of the anode 2a and the temperature sensor T2 for detecting the temperature of the anode 2a may not be provided.

<3>
In the above embodiment, the valve V1 (an example of the “predetermined portion upstream of the reformer of the gas distribution system leading from the fuel gas generating device to the anode” of the present invention) is closed and the valve V2 (the “to anode” of the present invention is closed). Although an example in which the fuel gas generating device isolating process in the form of closing the example of the “closing portion of the gas supply path in the above” is performed has been described, the fuel gas generating apparatus isolating process in another form may be performed. For example, the valve V1 (an example of the “predetermined portion upstream of the reformer of the gas distribution system leading from the fuel gas generating device to the anode” in the present invention) is closed and the valve V3 (the “gas discharge from the anode in the present invention”) is closed. The fuel gas generation device isolation process may be performed in a form that closes an example of “a closed portion of the road”. In this case, the pressure reduction process can be performed by opening the valve V3.

<4>
In the other embodiment, the water amount adjuster 10 is operated in the stop state maintaining step to adjust the amount of stored water stored in the oxidant gas storage water tank 6a to the maximum water level, and the fuel gas storage water tank Although the example which adjusts the stored water amount stored in 4a to the said minimum water level was demonstrated, you may operate the water amount regulator 10 at another process. For example, the water amount regulator 10 may be operated in the stop transition process. Specifically, in the stop transition process, the water amount regulator 10 is operated to increase the amount of stored water stored in the oxidant gas storage water tank 6a, and the water amount controller 10 is operated to store fuel gas. You may perform both or any one of the process which reduces the amount of stored water stored in the water tank 4a.

  In the stop transition process, when the water amount regulator 10 is operated to increase the amount of stored water stored in the oxidant gas storage water tank 6a, the upstream side oxidant gas storage water tank 6a from the cathode 2b. The volume up to the water surface becomes smaller. That is, the oxidant gas that can flow into the cathode 2b can be reduced. In addition, in the stop transition process in which the operation of the fuel cell FC is shifted to the stop state in which the output of power from the fuel cell FC is stopped, a large amount of fuel gas containing hydrogen is still present upstream of the anode 2a. Even if the oxidant gas flows into the cathode 2b, it reacts with hydrogen present in the vicinity of the anode 2a and is easily consumed. As a result, it is possible to further reduce the oxidant gas that may enter the anode 2a from the cathode 2b through the electrolyte 2c.

  In the stop transition process, when the water amount regulator 10 is operated to reduce the amount of stored water stored in the fuel gas storage water tank 4a, the water surface of the fuel gas storage water tank 4a upstream from the anode 2a The volume until is increased. In addition, in the stop transition process in which the operation of the fuel cell FC is shifted to a stop state in which the output of power from the fuel cell FC is stopped, a large amount of fuel gas containing hydrogen still exists on the upstream side of the anode 2a. That is, more hydrogen can remain on the upstream side of the anode 2a, so that even if the oxidant gas flows into the cathode 2b, it reacts with the hydrogen present in the vicinity of the anode 2a and is easily consumed. As a result, it is possible to further reduce the oxidant gas that may enter the anode 2a from the cathode 2b through the electrolyte 2c.

  Alternatively, in the stop transition process, the water amount regulator 10 is operated to move the stored water from the fuel gas storage water tank 4a to the oxidant gas storage water tank 6a, thereby storing the water in the oxidant gas storage water tank 6a. Processing for increasing the amount of stored water and decreasing the amount of stored water stored in the fuel gas storage water tank 4a may be performed.

<5>
When the water amount adjuster 10 is operated in the stop transition process, the water amount adjuster 10 is operated to increase or decrease the amount of stored water stored in the oxidant gas storage water tank 6a at least once, and finally You may perform the process which increases the amount of stored water.
As described above, in the stop transition process in which the operation of the fuel cell FC is shifted to the stop state in which the output of power from the fuel cell FC is stopped, a large amount of fuel gas containing hydrogen still exists on the upstream side of the anode 2a. Therefore, even if the oxidant gas flows into the cathode 2b, it reacts with hydrogen present in the vicinity of the anode 2a and is easily consumed. When the amount of stored water stored in the oxidant gas storage water tank 6a is increased in this state (for example, when the amount of stored water is increased to the maximum water level), the oxidant gas storage water and the cathode 2b are interposed. A certain oxidant gas is pushed into the cathode 2b, and the oxidant gas and hydrogen in the vicinity of the anode 2a react and are consumed. As a result, the concentration of the oxidant gas is reduced in the vicinity of the cathode 2b.

Thereafter, when the amount of stored water stored in the oxidant gas storage water tank 6a is reduced (for example, when the amount of stored water is reduced to the lowest water level), the gas existing in the vicinity of the cathode 2b (that is, the oxidant gas). Gas) is returned between the oxidant gas storage water and the cathode 2b, and the concentration of the oxidant gas in the gas between the oxidant gas storage water and the cathode 2b is low due to diffusion. Become.
In this manner, the water amount regulator 10 is operated to increase or decrease the amount of stored water stored in the oxidant gas storage water tank 6a at least once, so that the oxidant gas storage water and the cathode 2b are interposed. The concentration of oxidant gas in a gas can be gradually lowered.
Further, since the amount of the oxidant gas storage water is finally increased to, for example, the maximum water level, the volume between the cathode 2b and the upstream surface of the oxidant gas storage water tank 6a is reduced. The gas containing the oxidant gas that may flow into the cathode 2b can be reduced.

<6>
In the above description, two level sensors are provided in each of the fuel gas storage water tank 4a and the oxidant gas storage water tank 6a, and the water volume regulator 10 controls the stored water volume at two levels of the highest water level and the lowest water level. Although the example which manages is demonstrated, you may manage the amount of stored water of each tank 4a and 6a by another method. For example, three or more level sensors may be provided for each of the tanks 4a and 6a, and the water amount adjuster 10 may manage the amount of stored water at these three or more water level levels.
Alternatively, one level sensor may be provided for each of the inner side walls of the tanks 4a and 6a, and the water amount adjuster 10 may manage the amount of stored water using the water level detected by the level sensor as the reference water level. For example, after the water amount adjuster 10 has adjusted the stored water amount to the reference water level, the stored water amount is adjusted to the minimum water level by discharging the stored water from the tank for a set time at a set flow rate, and the stored water amount is After adjusting to the reference water level, the stored water amount may be managed by a process of adjusting the stored water amount to the maximum water level by flowing the stored water into the tank at a set flow rate for a set time.
When the drainage flow rate per unit time to each of the tanks 4a and 6a and the inflow rate per unit time become values that are known in advance through experiments or the like, the discharge period of the stored water from the tank and the storage in the tank You may adjust the water level of the stored water in a tank only by control of the inflow period of water.

<7>
A system configuration having only one of the fuel gas storage water tank 4a and the oxidant gas storage water tank 6a may be employed. In a system having only the fuel gas storage water tank 4a, a process of reducing the amount of stored water stored in the fuel gas storage water tank 4a is performed in the stop state maintaining process or the stop transition process. In the system having only the oxidant gas storage water tank 6a, in the stop state maintaining process or the stop transition process, processing for increasing the amount of stored water stored in the oxidant gas storage water tank 6a is performed, or the stop transition is performed. In the process, after the process of increasing or decreasing the amount of stored water stored in the oxidant gas storage water tank 6a is performed at least once, the process of finally increasing the amount of stored water is performed.

  The present invention can be used to suppress deterioration of the anode and cathode of a fuel cell.

DESCRIPTION OF SYMBOLS 1 Fuel gas production | generation apparatus 1a Reformer 2a Anode 2b Cathode 2c Electrolyte 3 Gas supply path 4 Fuel gas humidifier 4a Fuel gas storage water tank 6 Oxidant gas humidifier 6a Oxidant gas storage water tank 7 Gas discharge Road 10 Water volume adjuster 11 Water level controller 12 Water level adjusting tank FC Fuel cell S1, S2, S3, S4 Fuel cell system

Claims (15)

A method for stopping and storing a fuel cell system comprising a fuel cell configured by providing an electrolyte between an anode supplied with a fuel gas containing hydrogen and a cathode supplied with an oxidant gas,
After performing a stop transition process for shifting the operation of the fuel cell to a stop state for stopping the output of power from the fuel cell, at a set timing while performing a stop state maintaining process for maintaining the stop state The hydrogen-containing gas supply process for supplying the hydrogen-containing gas to the anode is performed in a state where the supply of the gas to the cathode is stopped ,
In the stop state maintaining step, the hydrogen-containing gas supply process is performed at the set timing while the anode isolation process is performed to close the gas supply path to the anode and open the gas discharge path from the anode. To stop and store the fuel cell system. A fuel gas generation device for generating the fuel gas supplied to the anode using a reformer is connected to the gas supply path to the anode,
While the anode isolation process is continuously performed in the stop state maintaining step, when the set timing is reached, the gas supply path to the anode is opened and gas is allowed to flow from the fuel gas generator to the anode. The stop storage method of the fuel cell system according to claim 1, wherein the hydrogen-containing gas supply process is performed. A method for stopping and storing a fuel cell system comprising a fuel cell configured by providing an electrolyte between an anode supplied with a fuel gas containing hydrogen and a cathode supplied with an oxidant gas,
After performing a stop transition process for shifting the operation of the fuel cell to a stop state for stopping the output of power from the fuel cell, at a set timing while performing a stop state maintaining process for maintaining the stop state The hydrogen-containing gas supply process for supplying the hydrogen-containing gas to the anode is performed in a state where the supply of the gas to the cathode is stopped,
A fuel gas generation device for generating the fuel gas supplied to the anode using a reformer is connected to the gas supply path to the anode,
After starting the stopped state maintaining step, before performing the anode isolation process for closing the gas supply path to the anode and the gas discharge path from the anode in the stopped state maintaining step, or maintaining the stopped state Before performing the anode isolation process for closing the gas supply path to the anode and opening the gas discharge path from the anode in the process, or in the stop state maintaining process, the fuel gas generation device and the anode In a state in which gas flow is permitted, a predetermined portion upstream of the reformer of the gas flow system leading from the fuel gas generation device to the anode is closed and a gas discharge path from the anode is closed Before performing the anode isolation treatment, a predetermined upstream side of the reformer of the gas distribution system leading from the fuel gas generator to the anode The fuel gas generating device isolation process for closing the gas supply passage to the close and and the anode of the position, performed until the temperature of the reformer is below the set temperature,
If the pressure between the predetermined portion and the closed portion of the gas supply path to the anode exceeds the set pressure during the fuel gas generation device isolation process, the gas supply to the predetermined portion and the anode is performed. A method for stopping and storing a fuel cell system, wherein a pressure reduction process is performed to reduce the pressure between the closed portion of the road. In the pressure reduction process, the predetermined part and the closed part of the gas supply path to the anode are opened by opening the closed part of the gas supply path to the anode and allowing gas to flow from the fuel gas generator to the anode. The stopped storage method of the fuel cell system according to claim 3, wherein the pressure during the operation is reduced. A method for stopping and storing a fuel cell system comprising a fuel cell configured by providing an electrolyte between an anode supplied with a fuel gas containing hydrogen and a cathode supplied with an oxidant gas,
After performing a stop transition process for shifting the operation of the fuel cell to a stop state for stopping the output of power from the fuel cell, at a set timing while performing a stop state maintaining process for maintaining the stop state The hydrogen-containing gas supply process for supplying the hydrogen-containing gas to the anode is performed in a state where the supply of the gas to the cathode is stopped,
A fuel gas generation device for generating the fuel gas supplied to the anode using a reformer is connected to the gas supply path to the anode,
After starting the stopped state maintaining step, before performing the anode isolation process for closing the gas supply path to the anode and the gas discharge path from the anode in the stopped state maintaining step, or maintaining the stopped state Before performing the anode isolation process for closing the gas supply path to the anode and opening the gas discharge path from the anode in the process, or in the stop state maintaining process, the fuel gas generation device and the anode In a state in which gas flow is permitted, a predetermined portion upstream of the reformer of the gas flow system leading from the fuel gas generation device to the anode is closed and a gas discharge path from the anode is closed Before performing the anode isolation treatment, a predetermined upstream side of the reformer of the gas distribution system leading from the fuel gas generator to the anode The fuel gas generating device isolation process for closing the gas discharge passage from the closing to and the anode of the position, performed until the temperature of the reformer is below the set temperature,
If the pressure between the predetermined part and the closed part of the gas discharge path from the anode exceeds the set pressure while the fuel gas generator isolation process is being performed, gas discharge from the predetermined part and the anode is performed. A method for stopping and storing a fuel cell system, wherein a pressure reduction process is performed to reduce the pressure between the closed portion of the road. 6. The fuel according to claim 5, wherein, in the pressure reduction process, the pressure between the predetermined portion and the closed portion of the gas discharge path from the anode is reduced by opening a closed portion of the gas discharge passage from the anode. How to stop and store battery systems. The anode isolation process is performed by closing a gas supply path to the anode and a gas discharge path from the anode in the stop state maintaining step, and the setting while the anode isolation process is being performed. The stop storage method of the fuel cell system according to any one of claims 3 to 6, wherein the hydrogen-containing gas supply process is performed at a timing. The anode isolation process is performed by closing the gas supply path to the anode and opening the gas discharge path from the anode in the stop state maintaining step, while the anode isolation process is being performed. The method for stopping and storing the fuel cell system according to any one of claims 3 to 6, wherein the hydrogen-containing gas supply process is performed at the set timing. While the anode isolation process is continuously performed in the stop state maintaining step, when the set timing is reached, the gas supply path to the anode is opened and gas is allowed to flow from the fuel gas generator to the anode. The method for stopping and storing the fuel cell system according to claim 7 or 8, wherein the hydrogen-containing gas supply process is performed. The anode isolating process is performed in the stopped state maintaining step, in a state where gas flow between the fuel gas generation device and the anode is permitted, and the gas circulation system that communicates from the fuel gas generation device to the anode. Supplying the hydrogen-containing gas at the set timing while performing the anode isolation process, which is performed by closing the predetermined portion upstream of the reformer and closing the gas discharge path from the anode. The stop storage method of the fuel cell system as described in any one of Claims 3-6 which implements a process. While the anode isolation process is continuously performed in the stop state maintaining step, when the set timing is reached, the hydrogen is released from the fuel gas generating device by allowing the gas to flow into the anode by opening the predetermined portion. The stopped storage method of the fuel cell system according to claim 10, wherein the contained gas supply process is performed. The stop storage method of the fuel cell system according to any one of claims 1 to 11, wherein the hydrogen-containing gas supply processing is repeatedly performed at a plurality of the set timings. The method for stopping and storing a fuel cell system according to any one of claims 1 to 12, wherein the hydrogen-containing gas supply process is stopped after the hydrogen-containing gas supply process is performed for a predetermined period. The fuel gas supplied to the anode, which is connected to a temperature of the anode or a gas supply path to the anode, when a time from the start of the stop state maintaining process reaches a predetermined time, or The method for stopping and storing a fuel cell system according to claim 13, wherein it is determined that the hydrogen-containing gas supply processing is performed for a predetermined period when the temperature of the reformer of the generated fuel gas generator is lowered to a predetermined temperature. A fuel gas generation device for generating the fuel gas supplied to the anode using a reformer is connected to the gas supply path to the anode,
After stopping the hydrogen-containing gas supply processing, the gas supply path to the anode and the gas discharge path from the anode are closed, the gas supply path to the anode is closed, and the gas discharge path from the anode Or in a state where gas flow between the fuel gas generation device and the anode is permitted, upstream of the reformer of the gas flow system that leads from the fuel gas generation device to the anode. The fuel cell system storage stop method according to claim 13 or 14, wherein the fuel cell is stored in a form in which a predetermined portion on the side is closed and a gas discharge path from the anode is closed.

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