JP2005228524A - Fuel cell system and its power generation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system which operates effectively and stably and improves durability of a hydrogen separation film layer by preventing deterioration of the hydrogen separation film layer in the fuel cell, and also to provide its power generation system. <P>SOLUTION: The fuel cell system 1 comprises a reformer 2, a fuel cell 3, and a control device. The fuel cell 3 has an electrolyte body 31 made by laminating a hydrogen separation metal layer 311 and a proton conductor layer 312, an anode passage 32, a cathode passage 33, and a coolant passage 34. The control device, by operating a cathode gas controller 6, increases the pressure in the cathode passage 33 when the temperature T of the electrolyte body 31 exceeds the upper limit Tmax of the permissible operating temperature range Tp, and decreases the pressure in the cathode passage 33 when the temperature T of the electrolyte body 31 becomes below the lower limit Tmin of the permissible operating temperature range Tp of the electrolyte body 31. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fuel cell system having a fuel cell that generates power using hydrogen in a hydrogen-containing gas.

  A fuel cell system that generates power using reforming fuel and the like is used to generate a reformed gas containing hydrogen from reforming fuel and the like, and to extract high-purity hydrogen from the reformed gas. And a fuel cell for generating power by reacting oxygen with hydrogen in a proton state. The reformer performs, for example, a steam reforming reaction using a reforming fuel and water and a partial oxidation reaction using a reforming fuel and oxygen to generate the reformed gas. Further, the hydrogen separation membrane device includes a hydrogen separation membrane made of palladium or the like, and this hydrogen separation membrane has a property of allowing only hydrogen to permeate. In addition, the fuel cell includes an anode channel to which hydrogen that has passed through the hydrogen separation membrane is supplied, a cathode channel to which air or the like is supplied, and a proton conductor (between these channels ( Electrolyte).

In addition, the hydrogen separation membrane device has a reformed gas side flow channel to which the reformed gas is supplied and a permeate side flow channel connected to the fuel cell on both sides of the hydrogen separation membrane. . Then, the anode-side gas discharged from the anode channel or the cathode-off gas discharged from the cathode channel is allowed to flow as a purge gas in the permeate side channel, and the hydrogen that has permeated the hydrogen separation membrane is passed through the anode of the fuel cell. It is sent out to the flow path.
In the fuel cell system, hydrogen supplied to the anode channel is made into a proton state and allowed to pass through the proton conductor, and in the cathode channel, hydrogen in the proton state and oxygen in the air are reacted to form water. Power generation while generating. Examples of such a fuel cell system include those shown in Patent Documents 1 and 2.

  By the way, palladium or vanadium used for the hydrogen separation membrane exhibits good hydrogen permeation performance in the operating temperature range of, for example, 300 to 600 ° C., but it is known that performance deterioration is caused when the operating temperature range is exceeded. It has been. Therefore, by adjusting the amount of reaction performed in the reformer, or adjusting the flow rate of the purge gas flowing through the permeate-side flow path in the hydrogen separation membrane device, the temperature in the hydrogen separation membrane is within the operating range. It is controlled to become.

  However, the temperature in the hydrogen separation membrane may change abruptly due to, for example, changes in the composition and flow rate of the reformed gas supplied to the reformed gas side flow path. When the temperature in the hydrogen separation membrane changes abruptly in this way, it is not sufficient to perform the above control, and the temperature in the hydrogen separation membrane may be out of the operating temperature range.

JP 2003-151599 A Japanese Patent Laid-Open No. 2001-2223017

  The present invention has been made in view of such conventional problems, and can efficiently and stably operate a fuel cell system and prevent deterioration of a hydrogen separation metal layer in an electrolyte body of a fuel cell. Thus, an object of the present invention is to provide a fuel cell system capable of improving the durability of the hydrogen separation metal layer and a power generation method thereof.

1st invention is a fuel cell system provided with the fuel cell which generates electric power using hydrogen content gas containing hydrogen,
The fuel cell includes an anode channel to which the hydrogen-containing gas is supplied, a cathode channel to which a cathode gas is supplied, and an electrolyte body disposed between the cathode channel and the anode channel. Have
The electrolyte body has a hydrogen separation metal layer for permeating hydrogen in the hydrogen-containing gas supplied to the anode channel, and permeates the hydrogen permeated through the hydrogen separation metal layer in a proton state. And a proton conductor layer for reaching the cathode channel, and the electrolyte body includes an anode electrode formed on a surface of the proton conductor layer on the anode channel side, and the proton conduction layer. A cathode electrode formed on the surface of the body layer on the cathode flow path side,
A cathode gas regulator for adjusting the flow rate of the cathode gas supplied to the cathode passage or the pressure in the cathode passage is connected to the cathode passage, and the cathode gas regulator is controlled by a control device. Configured to be possible,
The controller controls the cathode gas regulator when the temperature of the electrolyte body exceeds a predetermined upper limit value or when the temperature of the electrolyte body rises exceeding a predetermined temperature change rate. In operation, the flow rate of the cathode gas supplied to the cathode flow path or the pressure in the cathode flow path is increased, while the temperature of the electrolyte body is less than a predetermined lower limit or the temperature of the electrolyte body When the temperature drops excessively, that is, when the temperature falls below a predetermined temperature change rate, the cathode gas regulator is operated to decrease the flow rate of the cathode gas supplied to the cathode flow path or the pressure in the cathode flow path. The fuel cell system is characterized in that the fuel cell system is configured to perform the above.

  The fuel cell system of the present invention includes a fuel cell including an electrolyte body formed by laminating the hydrogen separation metal layer and the proton conductor layer. And in the fuel cell system of this invention, since the said proton conductor layer can be used without impregnating a water | moisture content, the said fuel cell can be operated in the high temperature state of 300-600 degreeC, for example.

Meanwhile, in the cathode flow path of the fuel cell, oxygen in the cathode gas supplied to the cathode flow path and proton-state hydrogen supplied from the anode flow path to the cathode flow path through the electrolyte body. (H ⁺ , also referred to as hydrogen ion) reacts to produce water. This water generation reaction is expressed as 2H ^{+ +} 1/2 · O ₂ + 2e ⁻ → H ₂ O. And the said fuel cell system can generate electric power by taking out electric power from between the anode electrode and cathode electrode in the said electrolyte body while performing the said reaction.

The control of the temperature of the fuel cell using the cathode gas regulator is an emergency when the temperature of the electrolyte body of the fuel cell is out of the predetermined range or when it is predicted to be out of the predetermined range. Can be done to the state.
By the way, as an index indicating the power generation characteristics in the fuel cell, there is an IV characteristic indicating a relationship between a current density (I) and a voltage (V) extracted from between the anode electrode and the cathode electrode. It is known that the IV characteristics have the property that when the current density increases, the resistance of the fuel cell increases and the voltage decreases.

  Therefore, the present invention is intended to change the temperature of the hydrogen separation metal layer in the electrolyte body of the fuel cell by utilizing the property in the I / V characteristics in the emergency state. In particular, the present invention pays attention to the fact that the voltage loss (cathode overvoltage) due to the polarization resistance depending on the structure of the cathode electrode depends on the amount of oxygen or the partial pressure of oxygen in the cathode flow path. The temperature of the hydrogen separation metal layer can be changed by changing the amount.

That is, when the excessive temperature rises, the control device operates the reformed gas regulator to increase the flow rate of the cathode gas supplied to the cathode channel or the pressure in the cathode channel. As a result, the amount of oxygen or the partial pressure of oxygen in the cathode channel increases, and the cathode overvoltage (voltage loss) decreases. And in the state controlled so that the battery output electric power taken out between the said anode electrode and a cathode electrode may become fixed, a current density reduces with the increase in the voltage by the said cathode overvoltage decreasing.
Therefore, the calorific value is reduced due to the decrease in the cathode overvoltage and current density, the temperature rise of the fuel cell is suppressed, and the temperature of the hydrogen separation metal layer in the electrolyte body of the fuel cell can be lowered. Thereby, it can suppress that deterioration generate | occur | produces in the said hydrogen separation metal layer.

On the other hand, the control device operates the reformed gas regulator to reduce the flow rate of the cathode gas supplied to the cathode channel or the pressure in the cathode channel when the excessive temperature decreases. As a result, the amount of oxygen or the partial pressure of oxygen in the cathode channel decreases, and the cathode overvoltage (voltage loss) increases. And in the state controlled so that the battery output power taken out from between the anode electrode and the cathode electrode becomes constant, the current density increases as the voltage decreases due to the increase of the cathode overvoltage.
Therefore, the calorific value increases due to the increase in the cathode overvoltage and current density, the temperature drop of the fuel cell is suppressed, and the temperature of the hydrogen separation metal layer in the electrolyte body of the fuel cell can be increased. Also by this, it can suppress that deterioration generate | occur | produces in the said hydrogen separation metal layer.

  Therefore, according to the present invention, the fuel cell system can be operated efficiently and stably, and the hydrogen separation metal layer in the electrolyte body of the fuel cell is prevented from being deteriorated. Durability can be improved.

According to a second aspect of the present invention, there is provided a fuel cell system including a fuel cell that generates power using a hydrogen-containing gas containing hydrogen.
The fuel cell includes an anode channel to which the hydrogen-containing gas is supplied, a cathode channel to which a cathode gas is supplied, and an electrolyte body disposed between the cathode channel and the anode channel. Have
The electrolyte body has a hydrogen separation metal layer for permeating hydrogen in the hydrogen-containing gas supplied to the anode channel, and permeates the hydrogen permeated through the hydrogen separation metal layer in a proton state. And a proton conductor layer for reaching the cathode channel, and the electrolyte body includes an anode electrode formed on a surface of the proton conductor layer on the anode channel side, and the proton conduction layer. A cathode electrode formed on the surface of the body layer on the cathode flow path side,
The fuel cell system includes a control device that controls a current density in the battery output line by changing a required power in the battery output line connected to the anode electrode and the cathode electrode,
When the temperature of the electrolyte body exceeds a predetermined upper limit value or when the temperature of the electrolyte body rises above a predetermined temperature change rate, the control device is required for the battery output line. The electric power is decreased to reduce the current density in the battery output line, while the temperature of the electrolyte body is lower than a predetermined lower limit value or the temperature of the electrolyte body is decreased over a predetermined temperature change rate. In the fuel cell system, the power density in the battery output line is increased to increase the current density in the battery output line when the temperature is excessively lowered (Claim 4).

  Similarly to the above-described invention, the fuel cell system of the present invention also uses a fuel cell including an electrolyte body formed by laminating the hydrogen separation metal layer and the proton conductor layer. It is operated at a high temperature of ˜600 ° C. to generate power.

  The present invention is also intended to change the temperature of the hydrogen separation metal layer in the electrolyte body of the fuel cell by utilizing the properties in the IV characteristics in the emergency state. In particular, the present invention can change the temperature of the hydrogen separation metal layer directly by changing the power generation amount itself in the fuel cell, thereby changing the heat generation amount depending on the resistance of the fuel cell. is there.

That is, the control device in the fuel cell system of the present invention controls the current density in the battery output line by changing the required power in the battery output line connected to the anode electrode and the cathode electrode.
Here, the required power in the battery output line refers to the amount of power that the fuel cell system supplies to the load connected to the battery output line.

  And the said control apparatus reduces the electric power demanded in the said battery output line at the time of the said excessive temperature rise, and reduces the current density in this battery output line. As a result, the voltage loss depending on the resistance of the fuel cell is reduced, and the amount of heat generated by the fuel cell due to the voltage loss is reduced. Therefore, the temperature rise of the fuel cell is suppressed, and the temperature of the hydrogen separation metal layer in the fuel cell electrolyte body can be lowered. Thereby, it can suppress that deterioration generate | occur | produces in the said hydrogen separation metal layer.

  On the other hand, the control device increases the required power in the battery output line to increase the current density in the battery output line when the excessive temperature is lowered. As a result, the voltage loss depending on the resistance of the fuel cell increases, and the amount of heat generated by the fuel cell due to the voltage loss increases. Therefore, the temperature drop of the fuel cell is suppressed, and the temperature of the hydrogen separation metal layer in the fuel cell electrolyte body can be increased. Thereby, it can suppress that deterioration generate | occur | produces in the said hydrogen separation metal layer.

  Therefore, according to the present invention, the fuel cell system can be efficiently and stably operated, and the hydrogen separation metal layer in the electrolyte body of the fuel cell is not deteriorated. Can be improved.

A third invention includes a fuel cell that generates power using a hydrogen-containing gas containing hydrogen, and the fuel cell includes an anode channel to which the hydrogen-containing gas is supplied and a cathode to which a cathode gas is supplied. A flow path, and an electrolyte body disposed between the cathode flow path and the anode flow path, wherein the electrolyte body includes hydrogen in the hydrogen-containing gas supplied to the anode flow path. A hydrogen separation metal layer for permeating and a proton conductor layer for permeating the hydrogen permeated through the hydrogen separation metal layer in a proton state to reach the cathode channel. In addition, the electrolyte body includes an anode electrode formed on the surface of the proton conductor layer on the anode channel side, and a cathode electrode formed on the surface of the proton conductor layer on the cathode channel side. In the power generation method of a fuel cell system formed by,
The hydrogen-containing gas is supplied to the anode flow channel, and hydrogen in the hydrogen-containing gas is allowed to permeate the hydrogen separation metal layer from the anode flow channel, and is then in a proton state to permeate the proton conductor layer. To the cathode flow channel, and in the cathode flow channel, the hydrogen in the proton state and oxygen in the cathode gas are reacted to generate the power,
In addition, when the temperature of the electrolyte body exceeds a predetermined upper limit or when the temperature of the electrolyte body rises exceeding a predetermined temperature change rate, the cathode supplied to the cathode flow path When the gas flow rate or the pressure in the cathode flow path is increased, on the other hand, when the temperature of the electrolyte body becomes less than a predetermined lower limit value or when the temperature of the electrolyte body falls below a predetermined temperature change rate In a power generation method of a fuel cell system, the flow rate of the cathode gas supplied to the cathode flow path or the pressure in the cathode flow path is reduced when a certain excessive temperature drop occurs.

The power generation method of the fuel cell system according to the present invention uses a fuel cell including an electrolyte body formed by laminating the hydrogen separation metal layer and the proton conductor layer, as in the above invention, For example, power is generated by operating at a high temperature of 300 to 600 ° C.
And like the said invention, in the said emergency state, the said control apparatus can control the temperature of an electrolyte body using the said cathode gas regulator.

  Therefore, according to the present invention, the fuel cell system can be efficiently and stably operated, and the hydrogen separation metal layer in the electrolyte body of the fuel cell is not deteriorated. Can be improved.

A fourth invention includes a fuel cell that generates power using a hydrogen-containing gas containing hydrogen, and the fuel cell includes an anode channel to which the hydrogen-containing gas is supplied and a cathode to which a cathode gas is supplied. A flow path, and an electrolyte body disposed between the cathode flow path and the anode flow path, wherein the electrolyte body includes hydrogen in the hydrogen-containing gas supplied to the anode flow path. A hydrogen separation metal layer for permeating and a proton conductor layer for permeating the hydrogen permeated through the hydrogen separation metal layer in a proton state to reach the cathode channel. In addition, the electrolyte body includes an anode electrode formed on the surface of the proton conductor layer on the anode channel side, and a cathode electrode formed on the surface of the proton conductor layer on the cathode channel side. In the power generation method of a fuel cell system formed by,
The hydrogen-containing gas is supplied to the anode flow channel, and hydrogen in the hydrogen-containing gas is allowed to permeate the hydrogen separation metal layer from the anode flow channel, and is then in a proton state to permeate the proton conductor layer. To the cathode flow channel, and in the cathode flow channel, the hydrogen in the proton state and oxygen in the cathode gas are reacted to generate the power,
In addition, when the temperature of the electrolyte body exceeds a predetermined upper limit value or when the temperature of the electrolyte body rises beyond a predetermined temperature change rate, the anode electrode and the cathode electrode are Reducing the required power in the connected battery output line to reduce the current density in the battery output line, while the temperature of the electrolyte body is less than a predetermined lower limit or the temperature of the electrolyte body is a predetermined temperature In a power generation method for a fuel cell system, the power density in the battery output line is increased to increase the current density in the battery output line at the time of excessive temperature drop, which is when the rate of change exceeds the rate of change ( Claim 15).

The power generation method of the fuel cell system according to the present invention uses a fuel cell including an electrolyte body formed by laminating the hydrogen separation metal layer and the proton conductor layer, as in the above invention, For example, power is generated by operating at a high temperature of 300 to 600 ° C.
And like the said invention, in the said emergency state, the said control apparatus can control the temperature of an electrolyte body by changing the request | requirement electric power in the said battery output line.

  Therefore, according to the present invention, the fuel cell system can be efficiently and stably operated, and the hydrogen separation metal layer in the electrolyte body of the fuel cell is not deteriorated. Can be improved.

A preferred embodiment in the first to fourth inventions described above will be described.
In the first aspect of the invention, when the excessive temperature rises, the control device reduces the required power in the battery output line connected to the anode electrode and the cathode electrode to reduce the current density in the battery output line. On the other hand, it is preferable that the required power in the battery output line can be increased and the current density in the battery output line can be increased when the excessive temperature decreases (claim 2).

  In this case, in the emergency state of the fuel cell system, the control device controls the temperature of the fuel cell using the cathode gas regulator and changes the required power in the battery output line. By combining with control, more optimal temperature control can be performed. That is, for example, the control device normally performs temperature control using the cathode gas regulator when the fuel cell system enters the emergency state, and when an abnormal situation with a higher degree of emergency occurs. Can perform temperature control to change the required power in the battery output line.

The cathode gas regulator preferably includes a gas pressurizer for supplying the cathode gas to the cathode channel.
In this case, the control device can increase the discharge pressure in the gas pressurizer to increase the pressure in the cathode flow path, while reducing the discharge pressure in the gas pressurizer to reduce the cathode flow. The pressure in the path can be reduced. Therefore, the control device can easily increase or decrease the pressure in the cathode flow path, and can easily change the amount of heat generated due to the cathode overvoltage. Thereby, the temperature of the electrolyte body can be more easily controlled in the emergency state.

  In the present invention, the gas pressurizer refers to a device that can pressurize and send out gas, and refers to, for example, a pump or a compressor (compressor) (hereinafter the same).

  In the first and second aspects of the invention, the fuel cell has a refrigerant flow path to which a refrigerant for cooling the fuel cell is supplied, and the refrigerant flow path includes the refrigerant flow path. A refrigerant flow controller for adjusting the flow rate of the refrigerant flowing through the refrigerant is connected, and the refrigerant flow controller is configured to be controllable by the control device. The control device has a predetermined temperature of the electrolyte body. It is preferable that the refrigerant flow rate regulator is controlled so as to be maintained within the above range.

  By the way, the fuel cell generates heat by operating by performing the reaction. For this reason, the control device controls the temperature of the electrolyte body to be maintained within a predetermined range by operating the refrigerant flow rate regulator and adjusting the flow rate of the refrigerant flowing through the refrigerant flow path. Can do. Thus, for example, in a steady state of the fuel cell system in which no abnormality or the like is present in the fuel cell system, that is, in a steady state where the fuel cell system does not reach the excessive temperature rise or the excessive temperature drop, the control device The temperature of the electrolyte body can be controlled using the flow rate regulator.

  In the steady state, the flow rate of the hydrogen-containing gas supplied to the anode flow channel and the flow rate of the cathode gas supplied to the cathode flow channel can be controlled to be as small as possible and as constant as possible. . Therefore, the power generation amount in the fuel cell can be stabilized, and the fuel cell system can be operated efficiently and stably.

  Even in the emergency state, the temperature of the electrolyte body can be controlled by using the refrigerant flow rate regulator and the cathode gas regulator in combination. Also, in the emergency state, it is conceivable to control the temperature of the electrolyte body using only the refrigerant flow regulator, but the refrigerant flow rate through the refrigerant flow path is controlled by operating the refrigerant flow regulator. Increasing or decreasing it abruptly is not preferable because it increases the temperature distribution (temperature deviation) in the fuel cell.

Moreover, it is preferable that the fuel cell has a temperature detection unit that detects the temperature of the electrolyte body.
In this case, the temperature of the electrolyte body can be detected directly or indirectly by the temperature detector provided in the fuel cell. And the said control apparatus can recognize the temperature of the said electrolyte body by the said temperature detection part.

Further, the fuel cell system includes a pair of temperatures of the temperature of the hydrogen-containing gas supplied to the anode flow path and the temperature of the anode off-gas discharged from the anode flow path, or the cathode supplied to the cathode flow path. The temperature of the electrolyte body may be estimated from at least one of a pair of temperatures of a gas temperature and a cathode off-gas temperature discharged from the cathode flow path. ).
In this case, the control device can recognize the temperature of the electrolyte body without providing the temperature detector in the fuel cell.

Further, the fuel cell system includes a pair of temperatures of a temperature of the hydrogen-containing gas supplied to the anode flow path and a temperature of an anode off-gas discharged from the anode flow path, and the cathode gas supplied to the cathode flow path. And a pair of temperature of the cathode off gas discharged from the cathode flow path, or a pair of temperature of the refrigerant supplied to the refrigerant flow path and temperature of the refrigerant off gas discharged from the refrigerant flow path The temperature of the electrolyte body can be estimated from at least one of a pair of temperatures.
Also in this case, the control device can recognize the temperature of the electrolyte body without providing the temperature detector in the fuel cell.

The fuel cell system preferably includes a reformer that generates the hydrogen-containing gas to be supplied to the fuel cell from a reforming fuel.
In this case, as described above, since the fuel cell can be operated at a high temperature of, for example, 300 to 600 ° C., the hydrogen-containing gas can be directly supplied from the reformer to the fuel cell.
Further, the cathode off gas discharged from the cathode flow path can be directly sent to the reformer in a high temperature state close to the operating temperature of the fuel cell. Therefore, in the fuel cell system, the temperature at which the hydrogen-containing gas is generated in the reformer and the operating temperature in the fuel cell can be made much closer.

  Further, the reformer heats the reforming reaction channel by forming a reforming reaction channel that generates the hydrogen-containing gas from the reforming fuel and the combustion formed adjacent to the reforming reaction channel. The fuel cell system has a cathode offgas line for sending the cathode offgas discharged from the cathode channel to the reforming reaction channel, and is discharged from the anode channel. It is preferable that an anode offgas line for sending the anode offgas to the heating flow path and a refrigerant offgas line for sending the refrigerant offgas discharged from the refrigerant flow path to the heating flow path ( Claim 10).

  In this case, the ratio of the partial oxidation reaction performed in the reformer can be reduced by forming the reforming reaction channel and the heating channel in the reformer. Therefore, in the reforming reaction channel, the reforming fuel can be used as much as possible in the steam reforming reaction for generating the hydrogen and the like, and the amount of reforming fuel supplied to the reformer is reduced. be able to. Therefore, the energy efficiency in the fuel cell system can be further improved.

By the way, after the reaction is performed in the cathode flow path, the cathode off-gas discharged from the cathode flow path includes residual oxygen not used in the reaction, generated water generated by the reaction, and the fuel cell. The amount of heat generated by high temperature operation.
Therefore, when the cathode offgas is sent from the cathode channel to the reforming reaction channel via the cathode offgas line, in the reforming reaction channel, the residual oxygen and the generated water that the cathode offgas has and the In addition to reacting with the reforming fuel, the reaction can be carried out using the high-temperature thermal energy of the cathode offgas. Thereby, the energy efficiency of the fuel cell system can be further improved.

  Further, the anode off-gas discharged from the anode flow path includes hydrogen discharged without passing through the hydrogen separation metal layer in the electrolyte body, and a combustible gas such as carbon monoxide and methane contained in the hydrogen-containing gas. And the amount of heat generated by the high-temperature operation of the fuel cell. Further, when an oxygen-containing gas such as air is used as the refrigerant, the refrigerant off-gas discharged from the refrigerant flow path has oxygen contained in the refrigerant and passes through the fuel cell. The amount of heat that is heated.

  Therefore, the anode offgas is sent from the anode passage to the heating passage through the anode offgas line, and the refrigerant offgas is sent from the refrigerant passage to the heating passage through the refrigerant offgas line. Sometimes, in the heating channel, not only the combustible gas of the anode off gas and the oxygen of the refrigerant off gas can be burned, but also the combustion is performed using the high-temperature thermal energy of the anode off gas and the refrigerant off gas. It can be carried out. Thereby, the energy efficiency of the fuel cell system can be further improved.

  In the first aspect of the invention, a pressure regulating valve is disposed in the cathode offgas line, and the control device reduces the opening of the pressure regulating valve when the excessive temperature rises. Preferably, the pressure in the flow path is increased, and when the excessive temperature decreases, the opening of the pressure regulating valve is increased to decrease the pressure in the cathode flow path (claim 11).

  In this case, the control device can optimally adjust the opening of the pressure regulating valve in the steady state of the fuel cell system. The control device can reduce the opening of the pressure regulating valve to increase the pressure in the cathode flow path, while increasing the opening of the pressure regulating valve (for example, fully opening). The pressure in the cathode channel can be reduced. Therefore, the control device can easily increase or decrease the pressure in the cathode flow path, and can easily change the amount of heat generated due to the cathode overvoltage. Thereby, the temperature of the electrolyte body can be more easily controlled in the emergency state.

  The cathode offgas line is provided with a three-way regulating valve, and the control device operates the three-way regulating valve when the excessive temperature is lowered, and controls the cathode offgas that flows through the cathode offgas line. It is preferable that the pressure in the cathode flow path is reduced by exhausting the part (claim 12).

In this case, the control device can reduce the pressure in the cathode flow path by operating the three-way regulating valve to exhaust a part of the cathode off-gas when the excessive temperature decreases.
Therefore, the control device can easily reduce the pressure in the cathode flow path, and can easily increase the amount of heat generated due to the cathode overvoltage. Thereby, the temperature of the electrolyte body can be more easily controlled in the emergency state.

  In the third aspect of the invention, when the excessive temperature rises, the required power in the battery output line connected to the anode electrode and the cathode electrode is reduced to reduce the current density in the battery output line, When the temperature is excessively lowered, it is preferable to increase the current density in the battery output line by increasing the required power in the battery output line (claim 14).

  In this case, in the emergency state of the fuel cell system, the temperature control of the fuel cell using the cathode gas regulator is combined with the temperature control of the fuel cell performed by changing the required power in the battery output line. Thus, more optimal temperature control can be performed. That is, for example, when the fuel cell system enters the emergency state, temperature control using the cathode gas regulator is usually performed, and when an abnormal situation with a higher degree of emergency occurs, the battery output Temperature control that changes the required power in the line can be performed.

In the third and fourth aspects of the invention, the fuel cell has a refrigerant flow path to which a refrigerant for cooling the fuel cell is supplied. When performing the power generation, the electrolyte body It is preferable to control the flow rate of the refrigerant supplied to the refrigerant flow path so that the temperature of the refrigerant is maintained within a predetermined range.
In this case, as described above, in the steady state of the fuel cell system, the control device can control the temperature of the electrolyte body using the refrigerant flow rate regulator, and the fuel cell system can be efficiently and stably controlled. And can drive.

The fuel cell system preferably includes a reformer that generates the hydrogen-containing gas to be supplied to the fuel cell from a reforming fuel.
In this case, as described above, the hydrogen-containing gas can be directly supplied from the reformer to the fuel cell, and the temperature at which the hydrogen-containing gas is generated in the reformer and the operating temperature of the fuel cell are considerably different. You can get closer.

  In the first to fourth aspects of the invention, the predetermined range of the temperature of the electrolyte body in which the control device performs temperature control using the refrigerant flow rate regulator can favorably generate power in the fuel cell. Allowable operating temperature range. This allowable operating temperature range can be, for example, 300 to 600 ° C. In this case, the temperature of the hydrogen separation metal layer in the fuel cell electrolyte body can be maintained at a temperature at which hydrogen permeation performance can be exhibited. The allowable operating temperature range is more preferably 400 to 500 ° C. In this case, the temperature of the hydrogen separation metal layer in the electrolyte body of the fuel cell can be maintained at an optimum temperature that exhibits hydrogen permeation performance.

  Further, the predetermined upper limit value of the temperature of the electrolyte body can be the upper limit value of the allowable operating temperature range. Further, the predetermined upper limit value of the temperature of the electrolyte body can be set to a temperature slightly lower than the temperature at which diffusion of the metal constituting the hydrogen separation metal layer occurs, for example. Further, the predetermined lower limit value of the temperature of the electrolyte body can be a lower limit value of the allowable operating temperature range. Further, the predetermined lower limit value of the temperature of the electrolyte body can be set to a temperature slightly higher than the temperature at which hydrogen embrittlement or hydrogen poisoning of the metal constituting the hydrogen separation metal layer occurs, for example.

  In the above reformer, for example, a steam reforming reaction that generates hydrogen, carbon monoxide, and the like from the reforming fuel and water, and a part of the reforming fuel or a part that burns hydrogen and oxygen. An oxidation reaction. And while producing | generating hydrogen by steam reforming reaction, since this steam reforming reaction is endothermic reaction, the exothermic reaction as said partial oxidation reaction can be performed, and the reaction temperature in a reformer can be maintained high. .

  The reforming fuel can be, for example, a hydrocarbon fuel or an alcohol fuel. Examples of the hydrocarbon fuel include fuel gas such as methane and ethane, liquefied petroleum gas such as propane and butane, and gasoline such as octane. Examples of the alcohol fuel include methanol and ethanol.

Hereinafter, embodiments of the fuel cell system and the power generation method of the present invention will be described with reference to the drawings.
(Example 1)
As shown in FIGS. 1 and 2, the fuel cell system 1 of the present example includes a reformer 2 that generates a hydrogen-containing gas Ga containing hydrogen from a reforming fuel F made of a hydrocarbon fuel, and the reformer. And a fuel cell 3 that generates power using the hydrogen-containing gas Ga generated in step 2.
The reformer 2 includes a reforming reaction channel 21 that generates the hydrogen-containing gas Ga from the reforming fuel F, and combustion that is formed adjacent to the reforming reaction channel 21 to perform the reforming reaction flow. And a heating flow path 22 for heating the path 21.

  The fuel cell 3 includes an anode channel 32 to which the hydrogen-containing gas Ga is supplied from the reforming reaction channel 21, a cathode channel 33 to which a cathode gas Gc is supplied, and the cathode channel 33. An electrolyte body 31 disposed between the anode flow path 32 and a refrigerant flow path 34 to which a refrigerant gas Gr as a refrigerant for cooling the fuel cell 3 is supplied.

  Further, as shown in FIG. 2, the electrolyte body 31 includes a hydrogen separation metal layer (hydrogen permeable metal layer) 311 for allowing hydrogen in the hydrogen-containing gas Ga supplied to the anode flow path 32 to pass therethrough, It is formed by laminating a proton conductor layer 312 made of ceramics for allowing the hydrogen permeated through the hydrogen separation metal layer 311 to pass through in a proton state and reach the cathode channel 33. The electrolyte 31 is formed on the surface of the proton conductor layer 312 on the anode flow path 32 side and on the surface of the proton conductor layer 312 on the cathode flow path 33 side. The cathode electrode 331 is provided.

As shown in FIG. 1, the fuel cell system 1 includes a refrigerant flow rate regulator 7 that adjusts the flow rate of the refrigerant gas Gr supplied to the refrigerant channel 34 and the cathode gas supplied to the cathode channel 33. A cathode gas regulator 6 that regulates the flow rate of Gc or the pressure in the cathode flow path 33, and a control device that controls the refrigerant flow regulator 7 and the cathode gas regulator 6.
And the said control apparatus controls the said refrigerant | coolant flow regulator 7 so that the temperature T of the said electrolyte body 31 is maintained in the predetermined range (permissible operating temperature range Tp of the fuel cell 3).

Further, the control device operates the cathode gas regulator 6 when the temperature T of the electrolyte body 31 exceeds an upper limit value Tmax of the allowable operating temperature range Tp, and operates the cathode gas regulator 6 to operate the cathode flow rate. The flow rate of the cathode gas Gc supplied to the passage 33 or the pressure in the cathode passage 33 is increased.
On the other hand, when the temperature T of the electrolyte body 31 is lower than the lower limit value Tmin of the allowable operating temperature range Tp, the control device operates the cathode gas regulator 6 to operate the cathode gas regulator 6 when the temperature drops excessively. The flow rate of the cathode gas Gc supplied to the flow path 33 or the pressure in the cathode flow path 33 is reduced.
This will be described in detail below.

  As shown in FIGS. 1 and 2, the fuel cell system 1 of the present example includes a reformed gas supply line 42 for supplying the hydrogen-containing gas Ga from the reforming reaction channel 21 to the anode channel 32, and A cathode offgas line 46 for sending the cathode offgas Oc discharged from the cathode channel 33 to the reforming reaction channel 21 and an anode offgas Oa discharged from the anode channel 32 are sent to the heating channel 22. And a refrigerant offgas line 47 for sending the refrigerant offgas Or discharged from the refrigerant flow path 34 to the heating flow path 22.

  The reformer 2 is configured to generate the hydrogen-containing gas Ga by reacting the reforming fuel F and the cathode offgas Oc in the reforming reaction channel 21. The reformer 2 is configured to perform the heating in the heating flow path 22 by burning the anode offgas Oa and the refrigerant offgas Or.

As shown in FIGS. 1 and 2, the electrolyte body 31 is formed by laminating and joining a joined body in which the anode electrode 321 and the cathode electrode 331 are joined to the proton conductor layer 312 and the hydrogen separation metal layer 311. It will be.
Further, the hydrogen separation metal layer 311 of this example is made of a laminated metal of palladium (Pd) and vanadium (V). Note that the hydrogen separation metal layer 311 can be composed of palladium alone, or can be an alloy containing palladium or a composite of palladium and another metal. Further, the hydrogen separation metal layer 311 has a hydrogen permeation performance (hydrogen separation performance) exceeding 10 A / cm ² in terms of current density under an anode gas supply condition of 3 atm. Thus, the virtual conductive resistance of the hydrogen separation metal layer 311 is made small enough to be ignored.

The proton conductor layer 312 of this example is made of a perovskite oxide as ceramic. The conductive resistance of the proton conductor layer 312 is reduced until it is about the same as the conductive resistance of the solid polymer electrolyte membrane. As the perovskite-type oxide, such as those of BaCeO ₃ system, there is a SrCeO ₃ system.

As shown in FIG. 2, the electrolyte body 31 includes an anode electrode 321 (anode) formed on the surface of the proton conductor layer 312 on the anode flow channel 32 side, and the cathode of the proton conductor layer 312. It has a cathode electrode 331 (cathode) formed on the surface on the channel 33 side. A battery output line 36 for taking out electric power from the fuel cell 3 is connected between the anode electrode 321 and the cathode electrode 331.
In addition, the anode electrode 321 in the proton conductor layer 312 of this example is made of palladium constituting the hydrogen separation metal layer 311. In addition, the cathode electrode 331 in the proton conductor layer 312 of this example is formed of a Pt-based electrode catalyst. The anode electrode 321 can also be composed of a Pt-based electrode catalyst.

In this example, as shown in FIG. 1, the cathode offgas line 46 is provided with a cathode offgas three-way regulating valve 61 that can branch the cathode offgas Oc flowing therethrough into two.
Then, the fuel cell system 1 exhausts a part of the cathode offgas Oc flowing through the cathode offgas line 46 via the cathode offgas three-way regulating valve 61 and the rest of the reforming reaction in the reformer 2. It is configured to send to the flow path 21. Further, the cathode offgas three-way regulating valve 61 can adjust the distribution ratio between the flow rate of the cathode offgas Oc to be exhausted and the flow rate of the cathode offgas Oc sent to the reforming reaction channel 21. The flow rate of the cathode offgas Oc sent from the cathode offgas line 46 to the reforming reaction channel 21 in the reformer 2 can be adjusted by the cathode offgas three-way regulating valve 61.

Thereby, when the amount of oxygen in the cathode offgas Oc (the amount of residual oxygen that has not been used for the reaction in the fuel cell 3) is larger than the amount of oxygen necessary for the reforming reaction channel 21, the three-way regulating valve 61 for cathode offgas. By exhausting a part of the cathode offgas Oc via, the amount of residual oxygen in the cathode offgas Oc sent to the reforming reaction channel 21 can be maintained at an appropriate amount.
Each of the three-way regulating valves used in this example is a branch valve having an inlet port through which gas flows in, an outlet port and relief port through which gas flows out. And the branch valve of this example can adjust the distribution ratio of the flow volume of the gas which branches and flows into an exit port and a relief port. The same applies to the three-way regulating valves shown in the following embodiments.

  By the way, the flow rate of the hydrogen-containing gas Ga to the anode flow channel 32, the flow rate of the cathode gas Gc to the cathode flow channel 33, and the like change, and the ratio of the oxygen amount to the hydrogen amount in the proton state in the cathode flow channel 33 (cathode). When the stoichiometry changes, the amount of residual oxygen in the cathode off-gas Oc that has not been used for the reaction with proton hydrogen also changes. At this time, in particular, when the amount of residual oxygen is larger than the amount of oxygen necessary for the reforming reaction channel 21, a part of the cathode offgas Oc is exhausted through the cathode offgas three-way regulating valve 61. The flow rate of the cathode offgas Oc sent to the reforming reaction channel 21 can be reduced. Thereby, the residual oxygen amount in the cathode off gas Oc sent to the reforming reaction channel 21 can be maintained at an appropriate amount.

  In the fuel cell system 1, the cathode stoichiometry is consciously changed by changing the flow rate of the hydrogen-containing gas Ga to the anode flow channel 32 and the flow rate of the cathode gas Gc to the cathode flow channel 33. Can be made. At this time, it is possible to adjust the ratio between the amount of water (water content) generated by the reaction between proton-state hydrogen and oxygen in the cathode off-gas Oc and the amount of residual oxygen. Even at this time, by exhausting a part of the cathode offgas Oc through the cathode offgas three-way regulating valve 61, the amount of residual oxygen in the cathode offgas Oc sent to the reforming reaction channel 21 is set to an appropriate amount. Can be maintained.

  In the reforming reaction channel 21 of the reformer 2, S / C indicating the molar amount of water (S) in the cathode offgas Oc with respect to the molar amount of carbon (C) in the reforming fuel F is: For example, it can be set to 1.8-2.5. In the reforming reaction channel 21 of the reformer 2, O / C indicating the molar amount of oxygen (O) in the cathode offgas Oc relative to the molar amount of carbon (C) in the reforming fuel F is: For example, it can be set to 0.05 to 0.6.

Further, as shown in FIG. 1, in this example, the anode offgas line 45 is provided with an anode offgas three-way regulating valve 51 that can branch the anode offgas Oa flowing therethrough into two. Yes.
The fuel cell system 1 exhausts a part of the anode offgas Oa flowing through the anode offgas line 45 via the anode offgas three-way regulating valve 51, and the remainder is a heating channel in the reformer 2. 22 to send to. The anode off gas three-way regulating valve 51 can adjust the distribution ratio between the flow rate of the anode off gas Oa to be exhausted and the flow rate of the anode off gas Oa to be sent to the heating flow path 22. The flow rate of the anode offgas Oa sent from the anode offgas line 45 to the heating flow path 22 in the reformer 2 can be adjusted by the anode offgas three-way regulating valve 51.

  Thereby, the amount of combustible gas such as hydrogen in the anode off-gas Oa (residual hydrogen not permeated to the hydrogen separation metal layer 311 in the electrolyte 31 of the fuel cell 3), carbon monoxide, methane, etc. When the gas amount is larger than the required gas amount, a part of the anode off gas Oa is exhausted via the anode off gas three-way regulating valve 51, so that the combustible gas amount in the anode off gas Oa sent to the heating flow path 22 is appropriately set. Can be maintained in quantity.

As shown in FIG. 1, in this example, the refrigerant offgas line 47 is provided with a refrigerant offgas three-way regulating valve 71 that can branch the refrigerant offgas flowing therethrough into two. .
The fuel cell system 1 exhausts a part of the refrigerant off-gas Or flowing through the refrigerant off-gas line 47 via the refrigerant off-gas three-way regulating valve 71, and the remainder is a heating channel in the reformer 2. 22 to send to. The refrigerant offgas three-way regulating valve 71 can adjust the distribution ratio between the flow rate of the refrigerant offgas Or to be exhausted and the flow rate of the refrigerant offgas Or to be sent to the heating flow path 22.

  The flow rate of the refrigerant offgas Or sent from the refrigerant offgas line 47 to the heating flow path 22 in the reformer 2 can be adjusted by the refrigerant offgas three-way regulating valve 71. As a result, when the amount of oxygen in the refrigerant off-gas Or is larger than the amount of oxygen required for the heating flow path 22, a part of the refrigerant off-gas Or is exhausted via the refrigerant off-gas three-way regulating valve 71. The amount of residual oxygen in the refrigerant off-gas Or sent to the passage 22 can be maintained at an appropriate amount.

As shown in FIG. 1, the fuel cell system 1 has a fuel supply line 41 for supplying the reforming fuel F to the reforming reaction channel 21 in the reformer 2. The cathode offgas line 46 is connected to the fuel supply line 41, and the cathode offgas flowing through the cathode offgas line 46 and the reforming fuel F flowing through the fuel supply line 41 are mixed in this connecting portion. A reaction channel mixing valve 881 is provided. An air-fuel mixture of the reforming fuel F and the cathode offgas Oc is supplied to the reforming reaction channel 21 in the reformer 2.
The cathode offgas line 46 can be directly connected to the reforming reaction channel 21, and the cathode offgas Oc and the reforming fuel F can be mixed in the reforming reaction channel 21.

In the reforming reaction channel 21, a steam reforming reaction is performed by the reforming fuel F and water (high-temperature steam) contained in the cathode offgas Oc, and hydrogen, carbon monoxide, and the like are generated. . Further, in the reforming reaction channel 21, an oxidation reaction is performed by the reforming fuel F and oxygen contained in the cathode offgas Oc, and water, carbon monoxide, carbon dioxide, and the like are generated. Thus, the hydrogen-containing gas Ga containing hydrogen and water is generated by the steam reforming reaction and the oxidation reaction.
Further, the steam reforming reaction is an endothermic reaction, while the oxidation reaction is an exothermic reaction, and a decrease in temperature in the reforming reaction channel 21 can be suppressed by the oxidation reaction.

As shown in FIG. 1, in the fuel cell system 1 of the present example, the anode offgas line 45 and the refrigerant offgas line 47 are connected to the heating gas mixing line 22 in the reformer 2. 451. In addition, a heating passage mixing valve 882 that mixes the anode offgas Oa flowing through the anode offgas line 45 and the refrigerant offgas Or flowing through the refrigerant offgas line 47 is disposed at this connection portion. Then, an air-fuel mixture of the anode offgas Oa and the refrigerant offgas Or is supplied to the heating channel 22 in the reformer 2.
The anode off-gas line 45 and the refrigerant off-gas line 47 can be directly connected to the heating channel 22, respectively, and the anode off-gas Oa and the refrigerant off-gas Or can be mixed in the heating channel 22.

In the heating flow path 22, a combustion reaction is performed by a combustible gas such as hydrogen contained in the anode off-gas Oa and oxygen contained in the refrigerant off-gas Or to produce water and the like.
Thus, by performing a combustion reaction in the heating channel 22, heat can be transferred from the heating channel 22 to the reforming reaction channel 21, and the temperature in the reforming reaction channel 21 is kept high. Can be done. In this example, the amount of heat generated in the reformer 2 by substantially balancing the amount of heat generated by the steam reforming reaction and oxidation reaction in the reforming reaction channel 21 and the amount of heat generated by the combustion reaction in the heating channel 22. The temperature of the contained gas Ga is maintained within a predetermined temperature range.
Further, the combustion off gas after the combustion reaction is performed in the heating flow path 22 is discharged to the outside of the fuel cell system 1 from an exhaust line 49 connected to the outlet of the heating flow path 22.

  In addition, since the heating channel 22 is formed in the reformer 2, the rate of the oxidation reaction performed in the reforming reaction channel 21 can be reduced. Therefore, in the reforming reaction channel 21, the reforming fuel F can be used as much as possible in the steam reforming reaction for generating hydrogen and the like, and the reforming fuel F to the reforming reaction channel 21 can be used. Can be reduced.

Further, as shown in FIG. 1, the reforming reaction channel 21 in the reformer 2 and the anode channel 32 in the fuel cell 3 are modified so that the hydrogen-containing gas Ga generated in the reforming reaction channel 21 flows. A quality gas supply line 42 is connected.
A cathode gas supply line 43 for supplying the cathode gas Gc to the cathode channel 33 is connected to the cathode channel 33 in the fuel cell 3. The cathode gas Gc of this example is air, and the cathode gas supply line 43 is provided with a cathode gas pressurizer 60 that pressurizes and sends out air as the cathode gas Gc. The cathode gas pressurizer 60 in this example is a pump 60. On the other hand, the cathode gas pressurizer 60 may be a fan or a compressor.
As the cathode gas Gc, in addition to air, oxygen-containing gas or oxygen can be used.

  A refrigerant gas supply line 44 for supplying the refrigerant gas Gr to the refrigerant channel 34 is connected to the refrigerant channel 34 in the fuel cell 3. The refrigerant gas Gr of this example is air, and the refrigerant gas supply line 44 is provided with a refrigerant gas pressurizer 70 that pressurizes and sends out the air as the refrigerant gas Gr. The refrigerant gas pressurizer 70 in this example is a pump 70. On the other hand, the refrigerant gas pressurizer 70 can be a fan or a compressor.

  Further, the fuel cell system 1 includes the hydrogen-containing gas from the reforming reaction channel 21 in the reformer 2 to the anode channel 32 in the fuel cell 3 without using a heat exchanger or a condenser. It is configured to supply Ga directly. Further, the fuel cell system 1 is configured to directly supply the cathode offgas Oc from the cathode channel 33 in the fuel cell 3 to the reforming reaction channel 21 in the reformer 2 without using a heat exchanger or the like. Has been.

1 shows a case where one reforming reaction channel 21 and one heating channel 22 in the reformer 2 are formed. On the other hand, the reformer 2 can be configured by forming a plurality of reforming reaction channels 21 and heating channels 22 and arranging them alternately.
1 and 2 show a case where one anode channel 32, one cathode channel 33, and one coolant channel 34 are formed in the fuel cell 3, respectively. On the other hand, the fuel cell 3 may be configured by forming a plurality of anode channels 32, cathode channels 33, and refrigerant channels 34, and arranging them alternately.

Further, as shown in FIG. 2, the fuel cell 3 includes a temperature detection unit 35 that detects the temperature T of the electrolyte body 31. The control device is configured to receive the temperature signal from the temperature detector 35 and control the cathode gas regulator 6. The temperature detector 35 of this example is a temperature sensor 34, and this temperature sensor 34 is embedded in the fuel cell 3. Further, the temperature sensor 34 of this example is embedded in the refrigerant flow path 34, and the control device indirectly detects the temperature T of the electrolyte body 31 by measuring the temperature in the refrigerant flow path 34. be able to.
The temperature sensor 34 can also be embedded in the cathode channel 33 or in the separator 340 formed between the cathode channel 33 and the refrigerant channel 34. The temperature sensor 34 can also be provided directly on the electrolyte body 31, and the control device can also directly detect the temperature T of the electrolyte body 31.

  Further, the temperature sensor 34 as the temperature detection unit 35 can be embedded in each of the anode channel 32, the cathode channel 33, and the refrigerant channel 34. The control device can recognize when the excessive temperature rises from the highest temperature among the temperature sensors 34, and can recognize when the excessive temperature decreases from the lowest temperature among the temperature sensors 34. it can.

  The temperature T of the electrolyte 31 is a pair of temperatures of the temperature of the hydrogen-containing gas Ga supplied to the anode channel 32 and the temperature of the anode offgas Oa discharged from the anode channel 32, and the cathode channel 33. A pair of temperatures of the temperature of the cathode gas Gc supplied to the cathode and the temperature of the cathode off-gas discharged from the cathode flow path 33, or the temperature of the refrigerant gas Gr supplied to the refrigerant flow path 34 and the refrigerant flow path 34 are discharged. It can also be estimated from at least one of the pair of temperatures with the temperature of the refrigerant off-gas Or. In this case, the control device can recognize the temperature T of the electrolyte body 31 without burying the temperature detection unit 35 in the fuel cell 3.

  Specifically, as shown in FIG. 3, the temperature of the hydrogen-containing gas Ga and the temperature of the anode off gas Oa are determined by the thermometer 351 disposed in the reformed gas supply line 42 and the anode off gas line 45. It can detect from the thermometer 352 arrange | positioned. The temperature of the cathode gas Gc and the temperature of the cathode offgas Oc are detected from a thermometer 353 disposed in the cathode gas supply line 43 and a thermometer 354 disposed in the cathode offgas line 46. Can do. The temperature of the refrigerant gas Gr and the temperature of the refrigerant offgas Or are detected from a thermometer 355 disposed in the refrigerant gas supply line 44 and a thermometer 356 disposed in the refrigerant offgas line 47. be able to.

  Each of the thermometers 351 to 356 includes a flow rate of the hydrogen-containing gas Ga supplied to the anode flow channel 32, a flow rate of the cathode gas Gc supplied to the cathode flow channel 33, and a refrigerant gas Gr supplied to the refrigerant flow channel 34. What is used when adjusting the flow rate can also be used.

  As shown in FIG. 1, the refrigerant flow regulator 7 of this example is a pump 70 as the refrigerant gas pressurizer 70. Further, the cathode gas regulator 6 of this example is configured by using a pump 60 as the cathode gas pressurizer 60, the cathode offgas pressure regulating valve 62, and the cathode offgas three-way regulating valve 61. . The cathode offgas pressure regulating valve 62 of this example is a throttle valve that can throttle the flow path inside.

  In this example, the control device uses the refrigerant flow rate regulator 7 to adjust the temperature T of the electrolyte body 31 of the fuel cell 3 in the steady state of the fuel cell system 1 where there is no abnormality in the fuel cell system 1. Take control. The control of the temperature of the fuel cell 3 using the cathode gas regulator 6 is an emergency of the fuel cell system 1 when the temperature T of the electrolyte body 31 of the fuel cell 3 is out of the allowable operating temperature range Tp. To state.

And the control apparatus of this example can increase the discharge pressure in the pump 60 as the said cathode gas pressurizer 60 at the time of the said excessive temperature rise. Further, the control device can throttle the opening degree of the cathode offgas pressure regulating valve 62 when the excessive temperature rises. As a result, the control device can increase the pressure in the cathode flow path 33.
On the other hand, the control device can reduce the discharge pressure in the pump 60 as the cathode gas pressurizer 60 when the excessive temperature drops. Further, when the temperature drops excessively, the control device fully opens the opening of the cathode offgas pressure regulating valve 62 and operates the cathode offgas three-way regulating valve 61 to flow the cathode offgas flowing through the cathode offgas line 46. A part of Oc can be exhausted outside the fuel cell system 1. Thereby, the control device can reduce the pressure in the cathode channel 33.

Next, a method for generating power using the fuel cell system 1 and the effects of the fuel cell system 1 will be described in detail.
In this example, in the reforming reaction channel 21 of the reformer 2, the reforming fuel F sent from the fuel supply line 41 reacts with the cathode offgas Oc sent from the cathode offgas line 46. Thus, the hydrogen-containing gas Ga is generated. On the other hand, in the heating flow path 22 of the reformer 2, the anode offgas Oa sent from the anode offgas line 45 and the refrigerant offgas Or sent from the refrigerant offgas line 47 react to generate heat and heat. The channel 22 heats the reforming reaction channel 21. In this way, while the hydrogen-containing gas Ga is generated in the reforming reaction channel 21, it is sent from the reforming reaction channel 21 to the anode channel 32 in the fuel cell 3 by heating it from the heating channel 22. The temperature of the hydrogen-containing gas Ga can be maintained at a high temperature of 300 to 600 ° C.

  The temperature of the hydrogen-containing gas Ga supplied to the fuel cell 3 can be 300 to 600 ° C., but is more preferably 400 to 500 ° C. In this case, the temperature of the hydrogen separation metal layer 311 in the electrolyte body 31 of the fuel cell 3 can be maintained at an optimum temperature that exhibits hydrogen permeation performance, and the hydrogen separation metal layer 311 is deteriorated. This can be easily suppressed.

  The hydrogen-containing gas Ga generated in the reforming reaction channel 21 of the reformer 2 passes through the reformed gas supply line 42 and is supplied to the anode channel 32 in the fuel cell 3. Then, most of the hydrogen in the hydrogen-containing gas Ga supplied to the anode channel 32 passes through the hydrogen separation metal layer 311 in the electrolyte body 31 and reaches the proton conductor layer 312 in the electrolyte body 31. The hydrogen passes through the proton conductor layer 312 in a proton state.

In the cathode flow path 33, water in the proton state reacts with oxygen in the cathode gas Gc supplied from the cathode gas supply line 43 to generate water. In this example, the reaction in the fuel cell 3 is performed at a high temperature of 300 to 600 ° C., and the generated water becomes high-temperature steam.
Further, the fuel cell system 1 can generate electric power by performing the above reaction and taking out electric power from between the anode electrode 321 and the cathode electrode 331 in the electrolyte body 31 to the battery output line 36.

The fuel cell system 1 of this example includes a fuel cell 3 including an electrolyte body 31 formed by laminating the hydrogen separation metal layer 311 and the proton conductor layer 312. In the fuel cell system 1 of the present example, the proton conductor layer 312 is made of ceramics, and the proton conductor layer 312 can be used without being impregnated with water. It can be operated at a high temperature of ˜600 ° C. Therefore, the hydrogen-containing gas Ga can be directly supplied from the reformer 2 to the fuel cell 3.
Further, the cathode off-gas Oc discharged from the cathode channel 33 can be directly sent to the reformer 2 in a high temperature state close to the operating temperature of the fuel cell 3. Therefore, in the fuel cell system 1, the temperature at which the hydrogen-containing gas Ga is generated in the reformer 2 and the operating temperature in the fuel cell 3 can be made almost the same.

After the reaction is performed in the cathode channel 33, the cathode offgas Oc discharged from the cathode channel 33 is composed of oxygen (residual oxygen) not used in the reaction and water generated by the reaction. (Produced water) and the amount of heat generated by the high-temperature operation of the fuel cell 3.
The generated water in the cathode flow path 33 of the fuel cell 3 is, for example, high-temperature steam at 300 to 600 ° C., and this generated water is hardly impregnated in the proton conductor layer 312. Further, since the hydrogen separation metal layer 311 has a property of allowing only hydrogen to pass therethrough, the generated water does not pass from the cathode channel 33 to the anode channel 32. Therefore, the entire amount of the generated water can be recovered from the cathode flow path 33 through the cathode offgas line 46.

Thereby, in the fuel cell system 1, water necessary for the reaction in the reforming reaction channel 21 of the reformer 2 can be easily obtained from the cathode offgas Oc containing the generated water generated by the power generation of the fuel cell 3. A sufficient amount of water can be supplied to the reforming reaction channel 21. Further, in the fuel cell system 1, the amount of water supplied to the reforming reaction channel 21 can be adjusted using the total amount of generated water in the cathode offgas Oc.
Therefore, the setting of the operating condition of the fuel cell system 1 becomes easy, and the operation of the fuel cell system 1 can be easily stabilized.

  In the fuel cell 3, since the proton conductor layer 312 is used in a non-water-containing (liquid) state, components in the proton conductor layer 312 are vaporized, and this is converted into the generated water in the cathode channel 33. No elution. Therefore, the purity of the generated water in the cathode offgas Oc sent to the reformer 2 is not lowered, and the steam reforming reaction arranged in the reforming reaction channel 21 of the reformer 2 is performed. Problems such as poisoning do not occur in the reforming catalyst to be performed.

  In the fuel cell system 1, when the hydrogen-containing gas Ga is generated by reacting the reforming fuel F and the cathode offgas Oc in the reforming reaction channel 21 of the reformer 2, In the quality reaction channel 21, not only the residual oxygen contained in the cathode offgas Oc and a sufficient amount of generated water can be used, but also high-temperature thermal energy possessed by the cathode offgas Oc can be used. Therefore, in the reforming reaction channel 21, the reforming fuel F and the cathode offgas Oc having high-temperature thermal energy can be reacted to generate the hydrogen-containing gas Ga. Can improve the energy efficiency.

  The anode off-gas Oa discharged from the anode flow path 32 is hydrogen discharged without passing through the hydrogen separation metal layer 311 in the electrolyte 31 and carbon monoxide, methane contained in the hydrogen-containing gas Ga. And the amount of heat generated by the high-temperature operation of the fuel cell 3. Further, the refrigerant off-gas Or discharged from the refrigerant flow path 34 has oxygen contained in the refrigerant gas Gr, and has an amount of heat heated through the fuel cell 3.

  Therefore, the anode off gas Oa is sent from the anode channel 32 to the heating channel 22 via the anode off gas line 45, and the refrigerant off gas Or is sent from the refrigerant channel 34 to the heating channel 22 via the refrigerant off gas line 47. In the heating flow path 22, not only the combustible gas such as hydrogen contained in the anode offgas Oa and the oxygen contained in the refrigerant offgas Or can be combusted, but also the high temperatures of the anode offgas and the refrigerant offgas Or. Combustion can be performed using the thermal energy of Thereby, the energy efficiency in the heating flow path 22 can also be improved.

Further, in the fuel cell system 1 of this example, the temperature at which the hydrogen-containing gas Ga is generated in the reformer 2 and the operating temperature in the fuel cell 3 can be made substantially the same as described above. Therefore, in this example, it is not necessary to provide a heat exchanger, a condenser, or the like necessary due to the difference in temperature between the reformer 2 and the fuel cell 3. Therefore, energy loss due to the use of them does not occur, and the structure of the fuel cell system 1 can be simplified.
Therefore, according to the fuel cell system 1 of the present example, the structure can be simplified, and the total amount of generated water can be recovered from the cathode channel 33, and the cathode offgas Oc, anode offgas Oa, and refrigerant can be recovered. The energy efficiency of the fuel cell system 1 can be improved by utilizing the high-temperature thermal energy that each of the off-gass Or has.

Although illustration is omitted, when the operation of the fuel cell system 1 is started, water and oxygen (such as air) can be directly supplied to the reforming reaction channel 21 in the reformer 2, and reforming can be performed. Fuel and oxygen (air etc.) can be directly supplied to the heating flow path 22 in the vessel 2.
After the operation of the fuel cell system 1 is started, water and oxygen necessary for the reforming reaction channel 21 can be supplied only from the cathode offgas Oc. Hydrogen and oxygen can be supplied only from the anode offgas Oa and the refrigerant offgas Or.
Further, in the reforming reaction channel 21 in the reformer 2, the reforming fuel F supplied to the reforming reaction channel 21 can be smoothly vaporized by the high-temperature cathode offgas Oc.

  Further, when the fuel cell 3 of this example is operated at a high temperature of 300 to 600 ° C., for example, the hydrogen separation metal layer 311 is hardly affected by poisoning due to carbon monoxide or the like. Therefore, during the high temperature operation, the hydrogen-containing gas Ga containing carbon monoxide or the like can be directly supplied to the anode flow path 32 of the fuel cell 3 in addition to hydrogen.

By the way, when the temperature in the hydrogen separation metal layer 311 becomes lower than a predetermined temperature, a metal such as vanadium constituting the hydrogen separation metal layer 311 absorbs hydrogen, and the absorbed hydrogen causes hydrogen embrittlement or the like. As a result, the hydrogen separation metal layer 311 may be destroyed. Further, at this time, carbon monoxide or carbon dioxide in the hydrogen-containing gas Ga is adsorbed on a metal such as palladium constituting the hydrogen separation metal layer 311 to cause a poisoning problem, and the hydrogen permeation performance is deteriorated. On the other hand, when the temperature in the hydrogen separation metal layer 311 becomes higher than a predetermined temperature, metals such as palladium and vanadium constituting the hydrogen separation metal layer 311 diffuse, and at this time, the hydrogen permeation performance deteriorates. Resulting in.
Therefore, in order to maintain the hydrogen permeation performance of the hydrogen separation metal layer 311 well, it is necessary to maintain the temperature in the hydrogen separation metal layer 311 within the allowable operating temperature range Tp.

As shown in FIG. 4, as an index indicating the power generation characteristics in the fuel cell 3, the current density I [A / cm ² ] and the voltage V [V] taken out between the anode electrode 321 and the cathode electrode 331 are There is an I / V characteristic indicating the relationship of The graph shows the current density I on the horizontal axis and the voltage V on the vertical axis.
In the IV characteristics, when the current density increases, the conductive resistance of the fuel cell 3, that is, the conductive resistance of the hydrogen separation metal layer 311 and the proton conductor layer 312 in the electrolyte 31, and the anode electrode 321 It is known that the voltage loss Vr is generated due to the polarization resistance depending on the structure and the polarization resistance depending on the structure of the cathode electrode 331. This voltage loss Vr is known to increase the amount of heat generated by the fuel cell 3.

  Therefore, the fuel cell system 1 of the present example attempts to change the temperature of the hydrogen separation metal layer 311 in the electrolyte body 31 of the fuel cell 3 by utilizing the properties in the IV characteristics in the emergency state. It is. In particular, in this example, focusing on the fact that the voltage loss (cathode overvoltage) due to the polarization resistance depending on the structure of the cathode electrode 331 depends on the amount of oxygen or the partial pressure of oxygen in the cathode channel 33, The temperature of the hydrogen separation metal layer 311 in the electrolyte body 31 of the fuel cell 3 can be changed by changing the accompanying heat generation amount. Thus, in this example, the temperature of the hydrogen separation metal layer 311 can be maintained within an appropriate temperature range, and the hydrogen permeation performance of the hydrogen separation metal layer 311 can be favorably maintained.

Next, the method for controlling the temperature of the fuel cell 3 and the operation and effect of the method will be described in detail.
The fuel cell system 1 includes the refrigerant flow rate regulator 7 and the cathode gas regulator 6 as described above, and these can be controlled by the control device.
The fuel cell 3 generates heat by performing the reaction and the control device operates the discharge flow rate of the pump 70 in the refrigerant flow rate regulator 7 so as to enter the refrigerant flow path 34. By adjusting the flow rate of the refrigerant gas Gr to be supplied, the temperature T of the electrolyte body 31 is controlled to be maintained within the allowable operating temperature range Tp (in the range of 300 to 600 ° C. in this example). Thereby, in the steady state of the fuel cell system 1, the control device can control the temperature T of the electrolyte body 31 using the refrigerant flow rate regulator 7.

  In the steady state, the flow rate of the hydrogen-containing gas Ga supplied to the anode flow channel 32 and the flow rate of the cathode gas Gc supplied to the cathode flow channel 33 are controlled to be as small as possible and as constant as possible. can do. Therefore, the power generation amount in the fuel cell 3 can be stabilized, and the fuel cell system 1 can be operated efficiently and stably.

Further, in the steady state, the opening degree of the cathode offgas pressure regulating valve 62 can be fully opened.
When the fuel cell system 1 is operated, the flow rate to the outlet port and the relief port in the anode offgas three-way regulating valve 51, the cathode offgas threeway regulating valve 61, and the refrigerant offgas threeway regulating valve 71 are described. It is possible to adjust the distribution ratio of each of the off-gas Oa, Oc, and Or flowing through the off-gas lines 45, 46, and 47 in advance.

In the fuel cell system 1, for example, when an abnormality occurs such as when the composition, flow rate, etc. of the reforming fuel F supplied to the reforming reaction channel 21 in the reformer 2 suddenly increases, the electrolyte The temperature T of the body 31 may fall outside the allowable operating temperature range Tp and exceed the upper limit value Tmax (600 ° C. in this example) of the allowable operating temperature range Tp.
At this time, the control device recognizes that the fuel cell 3 is at an excessively high temperature, and increases the discharge pressure of the pump 60 in the cathode gas regulator 6. At this time, the control device can also throttle the opening degree of the cathode offgas pressure regulating valve 62.

Thus, by increasing the back pressure at the outlet of the cathode channel 33, the pressure in the cathode channel 33 increases, the oxygen partial pressure in the cathode channel 33 increases, and the cathode overvoltage (voltage loss) decreases. . In the state where the output power of the fuel cell 3 taken out between the anode electrode 321 and the cathode electrode 331 is controlled to be constant, with the increase in the voltage of the fuel cell 3 due to the decrease in the cathode overvoltage, The current density of the fuel cell 3 is reduced. That is, in FIG. 4, the I / V curve L0 changes to the I / V curve L1. In the figure, a line L indicates a theoretical voltage.
Therefore, the calorific value is reduced due to the decrease in the cathode overvoltage and current density, the temperature rise in the fuel cell 3 is suppressed, and the temperature of the hydrogen separation metal layer 311 in the electrolyte body 31 of the fuel cell 3 can be lowered. . Thereby, in the hydrogen separation metal layer 311, generation | occurrence | production of the said hydrogen embrittlement, poisoning, etc. can be suppressed, and it can suppress that degradation of hydrogen permeation performance generate | occur | produces.

  In particular, as shown in the present embodiment, when the refrigerant gas Gr as a gas body is used as the refrigerant for cooling the fuel cell 3, the flow rate of the refrigerant gas Gr is increased to increase the temperature T of the electrolyte body 31. Rather than lowering the temperature, the temperature T of the electrolyte body 31 can be lowered more quickly and efficiently by increasing the flow rate or pressure of the cathode gas Gc to lower the temperature T of the electrolyte body 31. That is, by reducing the temperature T of the electrolyte body 31 using the cathode gas Gc, the cooling by the sensible heat of the cathode gas Gc and the decrease in the calorific value of the fuel cell 3 work synergistically and quickly with less power. The temperature T of the electrolyte body 31 can be lowered.

In the fuel cell system 1, for example, when an abnormality occurs such as when the composition, flow rate, etc. of the reforming fuel F supplied to the reforming reaction channel 21 in the reformer 2 suddenly decreases, the electrolyte The temperature T of the body 31 may be out of the allowable operating temperature range Tp and lower than the lower limit value Tmin (300 ° C. in this example) of the allowable operating temperature range Tp.
At this time, the control device recognizes that the fuel cell 3 is at an excessively low temperature, and reduces the discharge pressure of the pump 60 in the cathode gas regulator 6. Further, at this time, the control device increases the exhaust amount to be exhausted from the relief port in the cathode offgas three-way regulating valve 61 while the opening degree of the cathode offgas pressure regulating valve 62 is fully opened.
The remaining part of the cathode offgas Oc is supplied to the reforming reaction channel 21 in the reformer 2.

In this way, the pressure in the cathode flow path 33 decreases, the oxygen partial pressure in the cathode flow path 33 decreases, and the cathode overvoltage (voltage loss) increases. In a state where the output power of the fuel cell 3 taken out between the anode electrode 32 and the cathode electrode 33 is controlled to be constant, along with the decrease in the voltage of the fuel cell 3 due to the increase in the cathode overvoltage, The current density of the fuel cell 3 increases. That is, in FIG. 4, the I / V curve L0 changes to the I / V curve L2.
Therefore, the amount of heat generation increases due to the increase in the cathode overvoltage and current density, the temperature decrease of the fuel cell 3 is suppressed, and the temperature of the hydrogen separation metal layer 311 in the electrolyte body 31 of the fuel cell 3 can be increased. Thereby, in hydrogen separation metal layer 311, generation | occurrence | production of metal diffusion etc. can be suppressed and generation | occurrence | production of deterioration of hydrogen permeation performance can be suppressed.

  Therefore, according to the fuel cell system 1 of the present example, the fuel cell system 1 can be efficiently and stably operated, and the hydrogen permeation performance of the hydrogen separation metal layer 311 in the electrolyte body 31 of the fuel cell 3 is deteriorated. As a result, the durability of the hydrogen separation metal layer 311 can be improved.

FIG. 5 shows a flowchart for controlling the temperature of the fuel cell 3 in the fuel cell system 1.
In the figure, in step S101, the required power required for the fuel cell 3, the temperature of the refrigerant gas Gr, and the like are detected. In S102, the flow rate of the refrigerant gas Gr supplied from the refrigerant flow rate regulator 7 to the refrigerant flow path 34 of the fuel cell 3 is adjusted according to an algorithm preset in the control device. Thus, in the steady state of the fuel cell system 1, the temperature of the fuel cell 3 (refrigerant temperature control) is controlled using the refrigerant flow rate regulator 7, and the temperature T of the electrolyte 31 in the fuel cell 3 is within the allowable operating temperature range. It controls so that it may be maintained in Tp.

  Next, in step S <b> 103, the control device detects the temperature T of the electrolyte body 31 by the temperature detection unit 35. In S104, it is determined whether or not the temperature T of the electrolyte body 31 that has performed the detection is higher than the upper limit value Tmax of the allowable operating temperature range Tp. When this determination is Yes, the temperature T of the electrolyte body 31 is higher than the upper limit value Tmax of the allowable operating temperature range Tp, and the control device assumes that the fuel cell system 1 is in an excessive temperature rise in the emergency state. S105 is executed. In S105, the control device controls the temperature of the fuel cell 3 using the cathode gas regulator 6 (cathode gas temperature control) to increase the pressure in the cathode flow path 33 of the fuel cell 3, S103 is executed again. Thus, the temperature T of the electrolyte body 31 can be reduced.

  On the other hand, when the determination in S104 is No, the temperature T of the electrolyte body 31 is equal to or lower than the upper limit value Tmax of the allowable operating temperature range Tp, and the control device of the electrolyte body 31 that has performed the above detection in S106. It is determined whether or not the temperature T is lower than the lower limit value Tmin of the allowable operating temperature range Tp. When this determination is Yes, the temperature T of the electrolyte body 31 is lower than the lower limit value Tmin of the allowable operating temperature range Tp, and the control device assumes that the fuel cell system 1 is at the time of excessive temperature drop in the emergency state. S107 is executed. In S107, the control device controls the temperature of the fuel cell 3 using the cathode gas regulator 6 to reduce the pressure in the cathode flow path 33 of the fuel cell 3, and executes S103 again. Thus, the temperature T of the electrolyte body 31 can be raised.

On the other hand, when the determination in S106 is No, the temperature T of the electrolyte body 31 is in the allowable operating temperature range Tp, and the control device recognizes that the fuel cell system 1 is in the steady state, and again S101 is executed.
In the steady state of the fuel cell system 1, S101 to S103 can be repeated to perform refrigerant temperature control. In the emergency state of the fuel cell system 1, S103 to S107 are repeated to determine the cathode gas temperature. Control can be performed. Thereafter, as the operation of the fuel cell system 1 ends, the temperature control of the fuel cell 3 can be appropriately ended.

In S102, if the temperature T of the electrolyte body 31 is detected in S103, it is based on the required power required for the fuel cell 3, the temperature of the refrigerant gas Gr, the temperature T of the electrolyte body 31, and the like. Thus, the flow rate of the refrigerant gas Gr can be adjusted.
In S105, it is not always necessary to increase the pressure in the cathode flow path 33 of the fuel cell 3, but only by increasing the flow rate of the cathode gas Gc supplied to the cathode flow path 33 of the fuel cell 3. it can. In S107, it is not always necessary to reduce the pressure in the cathode flow path 33 of the fuel cell 3, but only by reducing the flow rate of the cathode gas Gc supplied to the cathode flow path 33 of the fuel cell 3. it can.

  The controller recognizes the excessive temperature rise when the temperature T of the electrolyte body 31 rises above a predetermined temperature change rate, and the temperature T of the electrolyte body 31 changes to a predetermined temperature change rate. When the temperature drops beyond the range, it is possible to recognize the time when the excessive temperature drops. In this case, the control device can predict that the fuel cell system 1 may be in an emergency state. The control device can increase or decrease the pressure in the cathode channel 33 before the temperature T of the electrolyte body 31 reaches the upper limit value Tmax or the lower limit value Tmin. Can correspond to the state.

  The fuel cell system 1 can include a plurality of the fuel cells 3, and the cathode gas regulator 6 can be provided for each fuel cell 3. In this case, the temperature detector 35 is provided for each fuel cell 3, and the control device recognizes the temperature T of each electrolyte body 31, and sets the cathode gas regulator 6 for each fuel cell 3. It can be configured to control.

  In this case, when any of the plurality of fuel cells 3 enters the emergency state due to some change or the like, the control device applies only the fuel cell 3 in the emergency state to the above-described emergency state. The cathode gas regulator 6 can be operated to control the temperature, and an emergency situation can be quickly dealt with. In addition, the control device can continue control of the temperature using only the refrigerant flow regulator 7 for the remaining fuel cells 3, and suppress a decrease in power generation efficiency of the entire fuel cell system 1 in an emergency state. can do.

(Example 2)
In this example, in the emergency state of the fuel cell system 1, the control device changes the required power in the battery output line 36 connected to the anode electrode 321 and the cathode electrode 331, and the current in the battery output line 36 is changed. This is an example of controlling the density (see FIGS. 2 and 3).
That is, when the excessive temperature rises, the control device of this example reduces the required power in the battery output line 36 to reduce the current density in the battery output line 36, while the battery output increases when the excessive temperature decreases. The power density in the line 36 is increased to increase the current density in the battery output line 36.

The required power in the battery output line 36 refers to the amount of power that the fuel cell system 1 supplies to the load connected to the battery output line 36. In other words, the fuel cell system 1 for operating the load. This refers to the amount of power required.
Although illustration is omitted, the configuration of the fuel cell system 1 of this example is the same as that of Example 1 except that the cathode offgas pressure regulating valve 62 is not provided.

Also in this example, as in the first embodiment, in the steady state of the fuel cell system 1, the control device uses the refrigerant flow rate regulator 7 to set the temperature T of the electrolyte body 31 to the allowable level. It can be controlled to be maintained within the operating temperature range Tp.
This example also attempts to change the temperature of the hydrogen separation metal layer 311 in the electrolyte body 31 of the fuel cell 3 by utilizing the properties in the IV characteristics in the emergency state. In particular, in this example, by changing the power generation amount itself in the fuel cell 3, the amount of heat generated depending on the conductive resistance of the fuel cell 3 can be changed, and the temperature of the hydrogen separation metal layer 311 can be changed. Is.

  That is, the control device of the present example reduces the required power in the battery output line 36 and decreases the current density in the battery output line 36 when the excessive temperature rises. Thereby, the voltage loss depending on the conductive resistance of the fuel cell 3 is reduced, and the amount of heat generated by the fuel cell 3 due to the voltage loss is reduced. Therefore, an increase in the temperature of the fuel cell 3 is suppressed, and the temperature T of the electrolyte body 31 of the fuel cell 3 can be reduced. Thereby, it can suppress that deterioration generate | occur | produces in the hydrogen separation metal layer 311 in the electrolyte body 31. FIG.

  On the other hand, the control device increases the required power in the battery output line 36 and increases the current density in the battery output line 36 when the excessive temperature decreases. Thereby, the voltage loss depending on the conductive resistance of the fuel cell 3 is increased, and the amount of heat generated by the fuel cell 3 due to the voltage loss is increased. Therefore, a decrease in the temperature of the fuel cell 3 is suppressed, and the temperature T of the electrolyte body 31 of the fuel cell 3 can be increased. Thereby, it can suppress that deterioration generate | occur | produces in the hydrogen separation metal layer 311 in the electrolyte body 31. FIG.

Therefore, also in this example, the fuel cell system 1 can be operated efficiently and stably, and the hydrogen separation metal layer 311 in the electrolyte body 31 of the fuel cell 3 is not deteriorated, so that the hydrogen separation metal The durability of the layer 311 can be improved.
Also in this example, the other parts are the same as those in the first embodiment, and the same effects as those in the first embodiment can be obtained.

  In the emergency state of the fuel cell system 1, the control device controls the temperature of the fuel cell 3 using the cathode gas regulator 6 shown in the first embodiment and the battery shown in the present example. The control of the temperature of the fuel cell 3 for changing the required power in the output line 36 can be performed in combination.

The temperature of the fuel cell 3 that changes the required power in the battery output line 36 is controlled more quickly than the temperature control of the fuel cell 3 using the cathode gas regulator 6. It can be used when the temperature T is changed. On the other hand, the control of the temperature of the fuel cell 3 that changes the required power in the battery output line 36 directly changes the power generation amount of the fuel cell 3 itself. Therefore, it is preferable to control the temperature of the fuel cell 3 using the cathode gas regulator 6 as much as possible in order to always ensure the power generation amount of the fuel cell 3 at a predetermined level or more.
Also in this example, the other parts are the same as those in the first embodiment, and the same effects as those in the first embodiment can be obtained.

(Example 3)
In this example, as shown in FIG. 6, in the emergency state of the fuel cell system 1, not only the pressure in the cathode flow path 33 shown in the first embodiment is changed to control the temperature of the fuel cell 3, An example in which the pressure in the anode channel 32 is also changed to control the temperature of the fuel cell 3 will be described.
That is, the fuel cell system 1 of this example includes the anode gas regulator 5 that adjusts the flow rate of the hydrogen-containing gas Ga supplied to the anode channel 32 or the pressure in the anode channel 32. The control device is configured to control the anode gas regulator 5.

The anode gas regulator 5 uses an anode off-gas pressure regulating valve 52 disposed in the anode off-gas line 45 and a reformed gas three-way regulating valve 53 disposed in the reformed gas supply line 42. Configured.
When the temperature of the fuel cell system 1 rises excessively in an emergency state, the control device throttles the opening of the anode off-gas pressure regulating valve 52 in the anode gas regulator 5. As a result, the control device can increase the pressure in the anode flow path 32 and can decrease the temperature T of the electrolyte body 31 of the fuel cell 3.

On the other hand, the control device opens the relief port of the reformed gas three-way regulating valve 53 in the anode gas regulator 5 at the time of excessive temperature drop in the emergency state of the fuel cell system 1, and contains hydrogen that flows through the reformed gas supply line 42. A part of the gas Ga is sent to the cathode offgas line 46. Thereby, the control device can decrease the pressure in the anode flow path 32 and can increase the temperature T of the electrolyte body 31 of the fuel cell 3.
According to the fuel cell system 1 of this example, the temperature T of the electrolyte body 31 of the fuel cell 3 can be more rapidly controlled in the emergency state.

Also in this example, the temperature control of the fuel cell 3 for changing the required power in the battery output line 36 shown in the second embodiment can be used in combination.
Also in this example, the other parts are the same as those in the first embodiment, and the same effects as those in the first embodiment can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram showing a configuration of a fuel cell system in Example 1. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram showing a configuration of a fuel cell in Example 1. FIG. 3 is an explanatory diagram showing the configuration of another fuel cell in Example 1. 4 is a graph illustrating an I / V characteristic that is a relationship between the current density I and the voltage V, with the current density I on the horizontal axis and the voltage V on the vertical axis in Example 1. 2 is a flowchart showing a method of controlling the temperature of the fuel cell in the first embodiment. FIG. 6 is an explanatory diagram showing a configuration of a fuel cell system in Example 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell system 2 Reformer 21 Reformation reaction flow path 22 Heating flow path 3 Fuel cell 31 Electrolyte body 311 Hydrogen separation membrane layer 312 Proton conductor layer 32 Anode flow path 321 Anode electrode 33 Cathode flow path 331 Cathode electrode 34 Refrigerant Flow path 35 Temperature detection unit 36 Battery output line 45 Anode off gas line 46 Cathode off gas line 47 Refrigerant off gas line 6 Cathode gas regulator 60 Cathode gas pressurizer 61 Cathode off gas three-way regulating valve 62 Cathode off gas pressure regulating valve 7 Refrigerant flow rate regulation 70 Refrigerant gas pressurizer 71 Three-way regulating valve for refrigerant off-gas F Reforming fuel Ga Hydrogen-containing gas Oa Anode off-gas Gc Cathode gas Oc Cathode off-gas Gr Refrigerant gas Or Refrigerant off-gas T Temperature of electrolyte Tp Allowable operating temperature range Tma Permissible operating temperature range the upper limit value Tmin permissible operating temperature range of the lower limit of

Claims (17)

In a fuel cell system including a fuel cell that generates power using a hydrogen-containing gas containing hydrogen,
The fuel cell includes an anode channel to which the hydrogen-containing gas is supplied, a cathode channel to which a cathode gas is supplied, and an electrolyte body disposed between the cathode channel and the anode channel. Have
The electrolyte body has a hydrogen separation metal layer for permeating hydrogen in the hydrogen-containing gas supplied to the anode channel, and permeates the hydrogen permeated through the hydrogen separation metal layer in a proton state. And a proton conductor layer for reaching the cathode channel, and the electrolyte body includes an anode electrode formed on a surface of the proton conductor layer on the anode channel side, and the proton conduction layer. A cathode electrode formed on the surface of the body layer on the cathode flow path side,
A cathode gas regulator for adjusting the flow rate of the cathode gas supplied to the cathode passage or the pressure in the cathode passage is connected to the cathode passage, and the cathode gas regulator is controlled by a control device. Configured to be possible,
The controller controls the cathode gas regulator when the temperature of the electrolyte body exceeds a predetermined upper limit value or when the temperature of the electrolyte body rises exceeding a predetermined temperature change rate. In operation, the flow rate of the cathode gas supplied to the cathode flow path or the pressure in the cathode flow path is increased, while the temperature of the electrolyte body is less than a predetermined lower limit or the temperature of the electrolyte body When the temperature drops excessively, that is, when the temperature falls below a predetermined temperature change rate, the cathode gas regulator is operated to decrease the flow rate of the cathode gas supplied to the cathode flow path or the pressure in the cathode flow path. It is comprised so that it may make. The fuel cell system characterized by the above-mentioned.   The control device according to claim 1, wherein when the excessive temperature rises, the control device decreases a required power in a battery output line connected to the anode electrode and the cathode electrode to reduce a current density in the battery output line, A fuel cell system configured to increase a required power in the battery output line and increase a current density in the battery output line when the excessive temperature decreases.   3. The fuel cell system according to claim 1, wherein the cathode gas regulator includes a gas pressurizer for supplying the cathode gas to the cathode channel. In a fuel cell system including a fuel cell that generates power using a hydrogen-containing gas containing hydrogen,
The fuel cell includes an anode channel to which the hydrogen-containing gas is supplied, a cathode channel to which a cathode gas is supplied, and an electrolyte body disposed between the cathode channel and the anode channel. Have
The electrolyte body has a hydrogen separation metal layer for permeating hydrogen in the hydrogen-containing gas supplied to the anode channel, and permeates the hydrogen permeated through the hydrogen separation metal layer in a proton state. And a proton conductor layer for reaching the cathode channel, and the electrolyte body includes an anode electrode formed on a surface of the proton conductor layer on the anode channel side, and the proton conduction layer. A cathode electrode formed on the surface of the body layer on the cathode flow path side,
The fuel cell system includes a control device that controls a current density in the battery output line by changing a required power in the battery output line connected to the anode electrode and the cathode electrode,
When the temperature of the electrolyte body exceeds a predetermined upper limit value or when the temperature of the electrolyte body rises above a predetermined temperature change rate, the control device is required for the battery output line. The electric power is decreased to reduce the current density in the battery output line, while the temperature of the electrolyte body is lower than a predetermined lower limit value or the temperature of the electrolyte body is decreased over a predetermined temperature change rate. A fuel cell system configured to increase the current density in the battery output line by increasing the required power in the battery output line when the temperature drops excessively. 5. The fuel cell according to claim 1, wherein the fuel cell includes a refrigerant flow path to which a refrigerant for cooling the fuel cell is supplied.
A refrigerant flow rate regulator that adjusts the flow rate of the refrigerant flowing through the refrigerant flow channel is connected to the refrigerant flow channel, and the refrigerant flow rate regulator is configured to be controllable by the control device,
The fuel cell system, wherein the control device is configured to control the refrigerant flow controller so that the temperature of the electrolyte body is maintained within a predetermined range.   6. The fuel cell system according to claim 1, wherein the fuel cell includes a temperature detection unit that detects a temperature of the electrolyte body.   The fuel cell system according to any one of claims 1 to 5, wherein the fuel cell system includes a pair of temperatures of a temperature of the hydrogen-containing gas supplied to the anode passage and a temperature of an anode off-gas discharged from the anode passage. Alternatively, the temperature of the electrolyte body is estimated from at least one of a pair of temperatures of a temperature of the cathode gas supplied to the cathode flow path and a temperature of the cathode off-gas discharged from the cathode flow path. A fuel cell system configured as described above.   6. The fuel cell system according to claim 5, wherein the fuel cell system supplies a pair of temperatures, that is, a temperature of the hydrogen-containing gas supplied to the anode passage and a temperature of an anode off-gas discharged from the anode passage, to the cathode passage. A pair of temperatures of the temperature of the cathode gas and the temperature of the cathode offgas discharged from the cathode flow path, or the temperature of the refrigerant supplied to the refrigerant flow path and the temperature of the refrigerant off gas discharged from the refrigerant flow path The temperature of the electrolyte body is estimated from at least one of the pair of temperatures.   9. The fuel cell system according to claim 1, wherein the fuel cell system includes a reformer that generates the hydrogen-containing gas to be supplied to the fuel cell from a reforming fuel. A fuel cell system. 10. The reformer according to claim 9, wherein the reformer includes a reforming reaction channel that generates the hydrogen-containing gas from the reforming fuel, and is formed adjacent to the reforming reaction channel and performs combustion to perform the reforming reaction channel. A heating channel for heating the path,
The fuel cell system has a cathode offgas line for sending the cathode offgas discharged from the cathode channel to the reforming reaction channel, and an anode offgas sent from the anode channel to the heating channel. A fuel cell system comprising: an anode offgas line; and a refrigerant offgas line for sending the refrigerant offgas discharged from the refrigerant channel to the heating channel. In Claim 10, the cathode offgas line is provided with a pressure regulating valve,
When the excessive temperature rises, the control device decreases the opening of the pressure regulating valve to increase the pressure in the cathode flow channel, and when the excessive temperature decreases, increases the opening of the pressure regulating valve. A fuel cell system configured to reduce the pressure in the cathode flow path. In claim 10 or 11, a three-way regulating valve is disposed in the cathode offgas line,
The controller is configured to reduce the pressure in the cathode flow path by operating the three-way regulating valve and exhausting a part of the cathode offgas flowing through the cathode offgas line when the excessive temperature drops. A fuel cell system characterized by comprising: A fuel cell that generates power using a hydrogen-containing gas containing hydrogen, the fuel cell comprising: an anode channel to which the hydrogen-containing gas is supplied; a cathode channel to which a cathode gas is supplied; and the cathode An electrolyte body disposed between the flow path and the anode flow path, wherein the electrolyte body is a hydrogen for permeating hydrogen in the hydrogen-containing gas supplied to the anode flow path. A separation metal layer; and a proton conductor layer for allowing the hydrogen that has passed through the hydrogen separation metal layer to pass through in a proton state to reach the cathode channel, and the electrolyte body. Is a fuel having an anode electrode formed on the surface of the proton conductor layer on the anode flow path side and a cathode electrode formed on the surface of the proton conductor layer on the cathode flow path side. In the power generation method of the pond system,
The hydrogen-containing gas is supplied to the anode flow channel, and hydrogen in the hydrogen-containing gas is allowed to permeate the hydrogen separation metal layer from the anode flow channel, and is then in a proton state to permeate the proton conductor layer. To the cathode flow channel, and in the cathode flow channel, the hydrogen in the proton state and oxygen in the cathode gas are reacted to generate the power,
In addition, when the temperature of the electrolyte body exceeds a predetermined upper limit or when the temperature of the electrolyte body rises exceeding a predetermined temperature change rate, the cathode supplied to the cathode flow path When the gas flow rate or the pressure in the cathode flow path is increased, on the other hand, when the temperature of the electrolyte body becomes less than a predetermined lower limit value or when the temperature of the electrolyte body falls below a predetermined temperature change rate A power generation method for a fuel cell system, characterized by reducing a flow rate of the cathode gas supplied to the cathode channel or a pressure in the cathode channel when a certain excessive temperature drop occurs.   14. When the excessive temperature rises, the required power in the battery output line connected to the anode electrode and the cathode electrode is reduced to reduce the current density in the battery output line. A power generation method for a fuel cell system, wherein the required power in the battery output line is increased to increase the current density in the battery output line. A fuel cell that generates power using a hydrogen-containing gas containing hydrogen, the fuel cell comprising: an anode channel to which the hydrogen-containing gas is supplied; a cathode channel to which a cathode gas is supplied; and the cathode An electrolyte body disposed between the flow path and the anode flow path, wherein the electrolyte body is a hydrogen for permeating hydrogen in the hydrogen-containing gas supplied to the anode flow path. A separation metal layer; and a proton conductor layer for allowing the hydrogen that has passed through the hydrogen separation metal layer to pass through in a proton state to reach the cathode channel, and the electrolyte body. Is a fuel having an anode electrode formed on the surface of the proton conductor layer on the anode flow path side and a cathode electrode formed on the surface of the proton conductor layer on the cathode flow path side. In the power generation method of the pond system,
The hydrogen-containing gas is supplied to the anode flow channel, and hydrogen in the hydrogen-containing gas is allowed to permeate the hydrogen separation metal layer from the anode flow channel, and is then in a proton state to permeate the proton conductor layer. To the cathode flow channel, and in the cathode flow channel, the hydrogen in the proton state and oxygen in the cathode gas are reacted to generate the power,
In addition, when the temperature of the electrolyte body exceeds a predetermined upper limit value or when the temperature of the electrolyte body rises beyond a predetermined temperature change rate, the anode electrode and the cathode electrode are Reducing the required power in the connected battery output line to reduce the current density in the battery output line, while the temperature of the electrolyte body is less than a predetermined lower limit or the temperature of the electrolyte body is a predetermined temperature A power generation method for a fuel cell system, characterized by increasing a required power in the battery output line to increase a current density in the battery output line when an excessive temperature drop occurs when the change rate exceeds the rate of change. The fuel cell according to any one of claims 13 to 15, wherein the fuel cell has a refrigerant flow path to which a refrigerant for cooling the fuel cell is supplied.
A power generation method for a fuel cell system, wherein when performing the power generation, a flow rate of the refrigerant supplied to the refrigerant flow path is controlled so that a temperature of the electrolyte body is maintained within a predetermined range.   The fuel cell system according to any one of claims 13 to 16, further comprising a reformer that generates the hydrogen-containing gas to be supplied to the fuel cell from a reforming fuel. A power generation method of the fuel cell system.

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