JP2007018987A - Fuel cell power generation system, its starting method, and starting program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a starting method of a fuel cell power generation system capable of restraining micro degradation of an oxidant electrode which can be problematic in a long-period operation, by correcting potential gradients of the oxidant electrode within a cell surface generated when started up. <P>SOLUTION: In a power generation starting operation, after beginning supply of reformed gas to a fuel electrode with supply of air stopped to the oxidant electrode, an electric control device 3 is put in a current source mode, and a direct current equivalent to a load current is made to flow from the oxidant electrode to the fuel electrode through an outside circuit (S301 to S303). After a unit cell voltage with the fuel electrode as reference reaches a load operation starting voltage Vo, the electric control device 3 is switched to a load operation mode (S305) at a point of elapsing for a predetermined retention time Th1 (YES of S304), and at the same time, air is supplied to the oxidant electrode (S306), a load current is increased until a load current density reaches Ir (S307, S308) to complete the starting operation. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel cell system that generates power by an electrochemical reaction by supplying fuel and an oxidant to a fuel cell stack configured by stacking a plurality of single cells, and a starting method and a starting program thereof.

  The fuel cell power generation system supplies a fuel such as hydrogen and an oxidant such as air to the fuel cell body and causes them to react electrochemically, thereby converting the chemical energy of the fuel directly into electrical energy and taking it out. It is a power generation device. This fuel cell power generation system is characterized by high efficiency and excellent environmental performance despite its relatively small size. Moreover, it can be applied as a cogeneration system by collecting the heat generated by power generation as hot water or steam.

  Such fuel cell bodies are classified into various types depending on the difference in electrolytes. Among them, the polymer electrolyte fuel cell using a solid polymer electrolyte membrane as the electrolyte has low-temperature operability and high performance. From the characteristics such as power density, it is suitable for use as a power source for small cogeneration systems and electric vehicles for general home use, and the market size is expected to expand rapidly in the future.

  This polymer electrolyte fuel cell power generation system is, for example, a reformer, a reformer for producing hydrogen-containing gas from hydrocarbon fuels typified by city gas, LPG, etc., taking a small cogeneration system for general households as an example. The fuel cell stack that generates electromotive force by supplying the hydrogen-containing gas and air in the atmosphere produced by the gas generator to the fuel electrode and the oxidant electrode, and the electricity that supplies the electric energy generated by the fuel cell stack to the external load It comprises a control device and a heat utilization system that recovers heat generated by power generation.

  In this way, fuel operation is premised on the operation of the fuel cell power generation system. Therefore, the higher the power generation efficiency defined by the amount of power generated relative to the amount of fuel input, the lower the amount of fuel used and the higher the user merit. Become. Therefore, the power generation efficiency is an index indicating the performance of the fuel cell power generation system.

  In this fuel cell power generation system, the fuel cell stack that actually takes charge of the power generation function has a problem that the voltage decreases with time due to various factors associated with the operation, resulting in a decrease in power generation efficiency. That is, suppressing the voltage drop with time of the fuel cell stack is the most important point in providing a fuel cell power generation system with high power generation efficiency.

  In general, such a fuel cell power generation system is operated by periodically starting and stopping according to a user's power demand. Air enters the oxidizer electrode from the outside. When the oxidant electrode is held at such a high potential that air is mixed in, the catalyst is deteriorated. For example, as described in Patent Document 1, the oxidant electrode is set in a reducing atmosphere. A method of stopping storage in a state is adopted.

  Further, even when the starting operation is performed from the stopped storage state, the catalyst is deteriorated if the oxygen is present in the oxidizer electrode and is kept in the no-load state. Therefore, for example, as described in Patent Document 2, there is proposed a method for transferring power generation without holding the oxidant electrode at a high potential by connecting to a variable resistor before connecting to an external load. Yes.

Thus, in the start-up method and the stop storage method described in Patent Document 1 and Patent Document 2, catalyst deterioration due to sintering is prevented by preventing the oxidant electrode from being held at a high potential. There is an advantage that it can be greatly improved.
JP 2002-93448 A Japanese Patent Laid-Open No. 5-251101

  However, when the present inventors have repeatedly studied to elucidate the cause of deterioration of the fuel cell, the conventional method for starting and stopping the fuel cell power generation system as described above should still be solved as follows. It turns out that there are still challenges.

  In a conventional fuel cell power generation system, by supplying an oxidant at the time of starting the system, a potential distribution is generated according to the oxidant concentration at the oxidant electrode, and is high at the oxidant electrode inlet and low at the outlet. Here, the higher the potential increase rate of the oxidant electrode or the greater the potential increase range, the greater the gradient of the oxidant electrode potential in the cell plane, particularly between the oxidant electrode inlet and outlet, and the smaller oxidant electrode It became clear that corrosion occurred.

  In other words, even when the system is started or stored at a stop, even if the high potential holding state of the oxidant electrode is avoided, if the start-up operation in which a gradient of the oxidant electrode potential is generated is repeated, the catalyst or gas constituting the oxidant electrode The minute corrosion of the material used for the diffusion layer and the separator gradually proceeds. Therefore, it has been found that when the fuel cell power generation system is operated for a long period of time, the catalyst activity and gas diffusivity gradually decrease as the electrode material corrodes, and the performance of the fuel cell stack deteriorates. .

  The present invention has been made to solve the above-mentioned problems, and its object is to correct the fuel cell oxidation which becomes a problem in long-term operation by correcting the potential gradient of the oxidant electrode in the cell plane generated at the time of startup. An object of the present invention is to provide a fuel cell power generation system capable of suppressing minute deterioration of the agent electrode, a starting method thereof, and a starting program.

  In order to achieve the above object, the invention according to claim 1 is a method for starting a fuel cell power generation system including a fuel cell stack including a fuel electrode and an oxidant electrode. The starting process includes an operation of reducing the oxidant electrode potential gradient in the cell plane accompanying the start of oxidant supply at the time of startup.

The invention described in claim 2 and claim 3 more specifically defines the operation of reducing the in-plane potential gradient of the oxidant electrode of the invention described in claim 1.
That is, the invention described in claim 2 is a fuel cell stack configured by stacking a plurality of unit cells each having a fuel electrode and an oxidant electrode arranged with an electrolyte interposed therebetween, and a fuel and an oxidant in the fuel cell stack. In the starting method of the fuel cell power generation system comprising the fuel supply device and the oxidant supply device for supplying the fuel cell stack, and the electric control device for controlling the load current of the fuel cell stack, An operation of starting the supply of fuel to the fuel electrode with the supply of air to the oxidant electrode stopped, and an external circuit from the oxidant electrode to the fuel electrode with the fuel supplied to the fuel electrode A direct current energizing operation for passing a direct current corresponding to a load current via the direct current energizing operation and an operation for supplying an oxidant to the oxidant electrode after the start of the direct current energizing operation.

  According to the invention of claim 2 having the above-described configuration, when air is supplied to the oxidant electrode, an oxygen reduction reaction occurs immediately. Potential rise can be suppressed. As a result, the amount of potential change and the potential change rate of the oxidant electrode are suppressed, and the potential gradient of the oxidant electrode in the cell plane is corrected. it can.

  According to a third aspect of the present invention, there is provided a fuel cell stack configured by laminating a plurality of single cells each having a fuel electrode and an oxidant electrode arranged with an electrolyte interposed therebetween, and a fuel and an oxidant in the fuel cell stack, respectively. In a start-up method of a fuel cell power generation system comprising a fuel supply device to be supplied, an oxidant supply device, and an electric control device for controlling a load current of the fuel cell stack, the oxidation is performed in a power generation start process of the fuel cell power generation system. An operation of starting the supply of fuel to the fuel electrode while the supply of air to the agent electrode is stopped, and a state in which the oxidant electrode has a higher potential than the fuel electrode with the fuel supplied to the fuel electrode. A polarization operation for connecting a DC voltage generating means for applying a DC voltage, and an operation for supplying an oxidant to the oxidant electrode after the start of the polarization operation. .

  According to the invention of claim 3 having the above-described configuration, after supplying fuel to the fuel electrode and before supplying air to the oxidant electrode, the oxidant electrode has a higher potential than the fuel electrode. When air is supplied to the oxidant electrode by performing a polarization operation to apply a DC voltage so that the oxidant electrode potential rises uniformly in advance, the oxidant near the oxidant inlet It is possible to suppress a potential gradient that accompanies an increase in polar potential. As a result, the potential change amount and the potential change speed of the oxidant electrode are suppressed, so that the potential gradient of the oxidant electrode in the cell plane is corrected.

  In addition, the fuel cell power generation system startup program according to claim 4 and claim 5 and the fuel cell power generation system according to claim 6 and claim 7 are the computer program and system aspects of the invention of the startup method. It is what was grasped from.

  According to the present invention, by correcting the potential gradient of the oxidant electrode in the cell plane that occurs at the time of startup, fuel cell power generation that can suppress minute deterioration of the fuel cell oxidant electrode that becomes a problem in long-term operation. A system, its startup method, and startup program can be provided.

  Embodiments to which the present invention is applied will be specifically described below with reference to the drawings.

(1) First Embodiment (1-1) Configuration FIG. 1 is a configuration diagram illustrating a fuel cell power generation system according to a first embodiment to which the present invention is applied. In the figure, solid lines connecting the blocks indicate connection diagrams of gas piping, and broken lines indicate connection diagrams of electrical wiring.

  As shown in FIG. 1, the fuel cell power generation system according to this embodiment includes a fuel cell stack 1, a reformer 2, and an electric controller 3. Note that the fuel cell stack 1 is actually configured by stacking a plurality of unit cells each having a fuel electrode and an oxidant electrode arranged with an electrolyte interposed therebetween. It is shown that the fuel cell stack 1 is composed of a fuel electrode 1a and an oxidant electrode 1b.

  The reformed gas obtained by steam reforming the city gas (13A) by the reformer 2 is supplied to the fuel electrode 1a of the fuel cell stack 1 through the fuel supply line 11 and discharged through the fuel discharge line 12. It is configured as follows. The oxidant electrode 1 b is configured such that air from the air blower 4 is supplied through the oxidant supply line 13 and discharged through the oxidant discharge line 14. Then, the electric energy obtained by the fuel cell stack 1 is configured to be supplied to the AC system power source 5 which is an external load by the electric control device 3.

  In addition, as shown in FIG. 2, the electric control device 3 includes an inverter having a function of converting DC power of the fuel cell stack 1 into AC and a function of converting AC power from the system AC power source 5 into DC power. 31 and a control device 32 for controlling the inverter 31 are incorporated. In FIG. 2, solid arrows indicate the control flow.

  The electric control device 3 configured as described above is used when the fuel cell stack is not generating power in addition to the load operation mode for controlling the fuel cell load current for extracting electric energy from the electromotive force of the fuel cell during fuel cell power generation. 1 has a current source mode in which a direct current can flow from the oxidizer electrode 1b to the fuel electrode 1a via the external circuit including the electric control device 3 using the system AC power source 5 as a power source. In addition, the amount of reformed gas supplied from the reformer 2 to the fuel electrode 1a has a function of determining according to the magnitude of the direct current according to a command from the system controller 100.

  Further, as shown in FIG. 1, valves 15 to 18 for sealing the fuel cell stack 1 are respectively provided in the lines 11 to 14 for supplying and discharging reformed gas and air to the fuel cell stack 1. Is provided. That is, a fuel electrode inlet valve 15 for closing the fuel supply line 11 is provided at the inlet of the fuel electrode 1a, and a fuel electrode outlet valve 16 for closing the fuel discharge line 12 is provided at the outlet of the fuel electrode 1a. Yes. Similarly, an oxidant electrode inlet valve 17 for closing the oxidant supply line 13 is provided at the inlet of the oxidant electrode 1b, and an oxidant electrode for closing the oxidant discharge line 14 at the outlet of the oxidant electrode 1b. An outlet valve 18 is provided.

  Further, each part of the fuel cell power generation system as described above is configured to be controlled by a control command from the system control device 100. That is, the mode switching and starting / stopping of the electric control device 3 are performed according to a control command from the system control device 100. Similarly, the reformer 2, the air blower 4, and the four valves 15 to 18 are also started, stopped, or opened / closed by being controlled by a control command from the system controller 100. A one-dot chain line in the drawing indicates a signal such as a control command exchanged between the system control apparatus 100 and each unit. Note that such a system control apparatus 100 is specifically realized by a microcomputer that stores a program specialized for system activation according to the present invention.

(1-1-1) Power Generation Startup Operation Procedure FIG. 3 is a flowchart showing a power generation startup operation procedure in the fuel cell power generation system startup method of the present embodiment. As shown in FIG. 3, when a start command is issued while the fuel cell power generation system is stopped, the supply of air to the oxidant electrode 1b is stopped (S301), and the reformer 2 supplies the fuel electrode. After the supply of the reformed gas to 1a is started (S302), the electric control device 3 is set to the current source mode (S303), and a direct current corresponding to the load current is passed from the oxidizer electrode 1b to the fuel electrode 1a via an external circuit. Shed.

  After the unit cell voltage (the average cell voltage of the fuel cell stack 1) based on the fuel electrode 1a reaches a preset load operation start voltage Vo (here, Vo = −0.1V). When the preset holding time Th1 (here, 10 seconds) has elapsed (YES in S304), the electric control device 3 is switched to the load operation mode (S305).

  In S305, the electric control device 3 is switched from the current source mode to the load operation mode, air is supplied to the oxidizer electrode (S306), and the load current is increased until the load current density becomes Ir (S307, S308). Complete the startup operation. As a result of this power generation start operation, the fuel cell power generation system is in a normal power generation state.

(1-1-2) Power Generation Stop Operation Procedure FIG. 4 is a flowchart showing a power generation stop operation procedure in the method for starting the fuel cell power generation system of this embodiment. As shown in FIG. 4, when a power generation stop command is issued during the power generation of the fuel cell power generation system, the supply of air from the air blower 4 to the oxidant electrode 1b is stopped (S401), and the oxidant supply line 13 closes the oxidant electrode inlet valve 17 (S402), and continues the load operation mode in the electric control device 3 (S403). The duration of the load operation mode is the time until the unit cell voltage (average cell voltage of the fuel cell stack 1) with respect to the fuel electrode 1a drops to a preset mode switching voltage Vt (NO in S404). is there. Here, as an example, it is assumed that the mode switching voltage Vt = 0.1V.

  Next, when the unit cell voltage with respect to the fuel electrode 1a is reduced to 0.1 V (YES in S404), the operation mode of the electric control device 3 is switched from the load operation mode to the current source mode, and the oxidant electrode An operation of passing a direct current from 1b to the fuel electrode 1a via an external circuit including the electric control device 3 is performed (S405). The duration of the current source mode is a period from when the unit cell voltage with respect to the fuel electrode 1a is decreased to be higher than −1.2 V and lower than 0 V, and then to a preset holding time Th. (NO in S406). Here, as an example, it is assumed that the holding time Th = 120 seconds.

  Subsequently, the electric control device 3 is stopped when 120 seconds have elapsed (YES in S406) after the unit cell voltage with respect to the fuel electrode 1a decreases to be higher than -1.2V and lower than 0V. (S407). Thereafter, the oxidant electrode outlet valve 18 provided in the oxidant discharge line 14 is closed (S408), the supply of the reformed gas from the reformer 2 to the fuel electrode 1a is stopped (S409), and the fuel supply line 11 closes the fuel electrode inlet valve 15 provided in the fuel electrode 11 and the fuel electrode outlet valve 16 provided in the fuel discharge line 12 (S410), thereby sealing the fuel cell stack 1 and completing the power generation stopping operation. As a result of this power generation stop operation, the fuel cell power generation system is stopped and stored.

  In addition, in such a stopped storage state of the fuel cell power generation system, when a start command for the fuel cell power generation system is issued again, the processing described in the section (1-1-1) Power generation start operation procedure is performed. Is made.

(1-2) Action FIG. 5 is a timing chart showing the start-up operation in the start-up method of the fuel cell power generation system of the present embodiment as described above, and the timing of control commands from the system control device 100 to each part of the system, and The time-dependent change of the average cell voltage of the fuel cell stack 1 is shown. Below, with reference to this FIG. 5, the effect | action by the starting method of the fuel cell power generation system of this embodiment is demonstrated.

  As shown in FIG. 5, when the fuel cell stack is in a stopped state, the oxidant electrode 1b is sealed in a reducing atmosphere, so the potential of the oxidant electrode 1b is near zero volts. When a start-up command is issued in this state, after supplying the hydrogen-rich reformed gas to the fuel electrode 1a (point A in the figure) and before supplying air to the oxidant electrode 1b (point B in the figure) As a result of the electric control device 3 being set to the current source mode, an energization operation is performed in which a direct current corresponding to the load current is passed from the oxidant electrode 1b to the fuel electrode 1a via an external circuit.

  As a result, when air is supplied to the oxidant electrode 1b (point B in the figure), an oxygen reduction reaction immediately occurs, so that an increase in potential near the oxidant electrode inlet having a high oxidant concentration can be suppressed. Therefore, the potential change amount and the potential change speed of the oxidant electrode 1b are suppressed, and the potential gradient of the oxidant electrode 1b in the cell plane is corrected.

FIG. 6 shows changes in the CO ₂ concentration contained in the oxidant electrode outlet exhaust gas immediately after the start of the fuel cell power generation system. Here, the CO ₂ concentration in the exhaust gas means the amount of corrosion of the carbon material in the oxidizer electrode 1b. In addition, Example 1 indicated by ● in the figure applies the method for starting the fuel cell power generation system of the present embodiment, and Comparative Example 1 indicated by Δ in the figure indicates that the fuel cell power generation system is in the starting operation. The conventional start-up method is applied in which an energization operation is not performed to flow a direct current from the oxidant electrode to the fuel electrode via an external circuit before supplying air to the oxidant electrode.

As can be seen from FIG. 6, in Example 1, compared with Comparative Example 1, the CO ₂ emission in the oxidant electrode exhaust gas caused by corrosion immediately after startup is greatly suppressed, and the cell plane at startup It can be seen that the corrosion of the minute oxidant electrode derived from the potential gradient of the oxidant electrode 1b is suppressed.

(1-3) Effect FIG. 7 is a diagram showing an effect obtained by the method for starting the fuel cell power generation system of the present embodiment as described above. That is, FIG. 7 shows the number of start / stop times and oxidation during the cycle test for Example 1 (◯ in the figure) and Conventional Example 1 (□ in the figure) to which the start method of the fuel cell power generation system of this embodiment is applied. 4 is a graph showing the relationship between the effective electrode surface area ratio of the electrode and the fuel cell stack when the start / stop cycle is executed 600 times with 12 hours of power generation and 12 hours of stop storage as one cycle. 1 shows the change in the effective surface area of the oxidant electrode catalyst constituting 1 (initial value: 100%).

  Here, in the conventional example 1 shown in FIG. 7, during the start-up operation of the fuel cell power generation system, before supplying air to the oxidant electrode, energization is performed by passing a direct current from the oxidant electrode to the fuel electrode via an external circuit. A conventional activation method that does not perform any operation is applied.

  As is clear from FIG. 7, in the conventional example 1, the effective surface area of the catalyst is reduced due to the deterioration of the catalyst of the oxidizer electrode as the number of start / stop operations increases. The reduction of the effective catalyst surface area accompanying the catalyst deterioration of the oxidizer electrode as seen in FIG.

  That is, according to the start-up method of the fuel cell power generation system of the present embodiment, when air is supplied to the oxidant electrode, an oxygen reduction reaction occurs immediately, so that the potential near the oxidant electrode inlet with a high oxidant concentration is present. The rise can be suppressed. Therefore, the potential change amount and potential change rate of the oxidant electrode are suppressed, and the potential gradient of the oxidant electrode in the cell plane is corrected. Therefore, corrosion of the minute oxidant electrode derived from these can be suppressed. . Therefore, it is possible to prevent a decrease in the effective catalyst surface area of the oxidizer electrode and a decrease in gas diffusivity, and a decrease in the voltage of the fuel cell stack.

(2) Second Embodiment The present embodiment is a modification of the first embodiment, and the internal configuration of the electric control device 3 is changed as follows. Since other configurations are the same as those of the first embodiment, description thereof is omitted.

(2-1) Configuration In the fuel cell power generation system of the present embodiment, the electric control device 3 is configured as shown in FIG. That is, the electric control device 3 includes an inverter 31 having a function of converting direct current power of the fuel cell stack 1 into alternating current and a function of converting alternating current power from the system AC power source 5 into direct current power. A DC-DC converter 33 that converts the direct current power into a predetermined voltage and a control device 32 that controls the inverter 31 and the DC-DC converter 33 are incorporated. In FIG. 8, the solid line arrows indicate the flow of control.

  The electric control device 3 configured as described above is used when the fuel cell stack is not generating power in addition to the load operation mode for controlling the fuel cell load current for extracting electric energy from the electromotive force of the fuel cell during fuel cell power generation. 1 has a DC voltage generation mode (DC voltage source mode) in which an arbitrary DC voltage is applied to the fuel cell stack 1 for polarization using the system AC power supply 5 as a power source.

(2-1-1) Power Generation Startup Operation Procedure FIG. 9 is a flowchart showing a power generation startup operation procedure in the fuel cell power generation system startup method of the present embodiment. As shown in FIG. 9, when a start command is issued while the fuel cell power generation system is stopped, the supply of air to the oxidizer electrode 1b is stopped (S901), and the fuel electrode from the reformer 2 is stopped. After the supply of the reformed gas to 1a is started (S902), the electric control device 3 is set to the DC voltage source mode (S903).

  Then, a DC voltage is applied to the oxidizer electrode at an increase rate of 5 mV / sec so that the unit cell voltage with respect to the fuel electrode becomes a preset load operation start voltage Vo (here, Vo = 0.5 V). And the electric control device 3 is loaded when a preset holding time Th2 (here, 10 seconds) elapses after the unit cell voltage reaches 0.5 V (YES in S904). Switch to the operation mode (S905).

  In S905, the electric control device 3 is switched from the DC voltage source mode to the load operation mode, and air is supplied to the oxidizer electrode (S906), and the load current is increased until the load current density becomes Ir (S907, S908). , Complete the startup operation. As a result of this power generation start operation, the fuel cell power generation system is in a normal power generation state.

(2-2) Action / Effect FIG. 10 is a timing chart showing the start-up operation in the start-up method of the fuel cell power generation system of the present embodiment as described above, and the timing of the control command from the system control device 100 to each part of the system. , And the time variation of the average cell voltage of the fuel cell stack 1 is shown. Below, with reference to this FIG. 10, the effect | action by the starting method of the fuel cell power generation system of this embodiment is demonstrated.

  As shown in FIG. 10, when the fuel cell stack is in a stopped state, the oxidant electrode 1b is sealed in a reducing atmosphere, so the potential of the oxidant electrode 1b is near zero volts. When a start-up command is issued in this state, after supplying the hydrogen-rich reformed gas to the fuel electrode 1a (point a in the figure) and before supplying air to the oxidizer electrode 1b (point b in the figure) As a result of the electric control device 3 being set to the DC voltage source mode, a DC voltage is applied so that the oxidizer electrode 1b becomes positive, and the polarization operation is performed.

  As a result, when air is supplied to the oxidant electrode 1b (point b in the figure), the oxidant electrode potential rises uniformly in advance. The potential gradient is suppressed. Further, the rate of increase of the oxidant electrode potential can be arbitrarily set by controlling the applied DC voltage.

Therefore, since the potential change amount and the potential change speed of the oxidant electrode are suppressed, the potential gradient of the oxidant electrode in the cell plane is corrected, and the minute oxidant electrode derived from these is corrected as in the first embodiment. Corrosion of is suppressed. Therefore, the present embodiment can provide the same effects as those of the first embodiment.
In addition, the power consumption in the DC voltage source mode, which is the potential gradient correcting operation for the oxidant electrode in the cell plane in the present embodiment, is also advantageous as compared to the first embodiment.

(3) Other Embodiments The present invention is not limited to the above-described embodiments, and various other variations can be implemented within the scope of the present invention. For example, the holding time shown for the power generation activation operation procedure is merely an example, and can be changed as appropriate.

  That is, according to the present invention, the electric control device is set to the current source mode after supplying the hydrogen-rich reformed gas to the fuel electrode and before supplying air to the oxidant electrode during the power generation start-up process of the fuel cell power generation system. As long as a direct current equivalent to the load current flows from the oxidant electrode to the fuel electrode via an external circuit, or by setting the electric control device to the direct current voltage source mode, the direct current is set so that the oxidant electrode becomes positive. As long as the polarization operation is performed by applying a voltage, the specific system configuration and power generation starting operation procedure can be changed as appropriate, and excellent effects can be obtained as well.

The figure which shows the structure of the fuel cell power generation system for implement | achieving 1st Embodiment of the starting method of the fuel cell power generation system which concerns on this invention. The figure which shows the structure of the electric control apparatus in 1st Embodiment of the starting method of the fuel cell power generation system which concerns on this invention. The flowchart which shows the electric power generation starting operation procedure in 1st Embodiment of the starting method of the fuel cell power generation system which concerns on this invention. The flowchart which shows the electric power generation stop operation procedure in 1st Embodiment of the starting method of the fuel cell power generation system which concerns on this invention. The timing chart which shows the electric power generation starting operation | movement in 1st Embodiment of the starting method of the fuel cell power generation system which concerns on this invention. It is a figure which shows the effect by 1st Embodiment of the starting method of the fuel cell power generation system which concerns on this invention, and is a graph which shows the relationship between the frequency | count of starting and stopping at the time of a cycle test, and the catalyst effective surface area ratio of an oxidizing agent electrode. It is a figure which shows the effect by 1st Embodiment of the starting method of the fuel cell power generation system which concerns on this invention, and shows the ratio with respect to the initial value of the fuel electrode catalyst effective surface area after a cycle test. The figure which shows the structure of the electric control apparatus in 2nd Embodiment of the starting method of the fuel cell power generation system which concerns on this invention. The flowchart which shows the electric power generation starting operation procedure in 2nd Embodiment of the starting method of the fuel cell power generation system which concerns on this invention. The timing chart which shows the electric power generation starting operation | movement in 2nd Embodiment of the starting method of the fuel cell power generation system which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel cell stack 1a ... Fuel electrode 1b ... Oxidant electrode 2 ... Reformer 3 ... Electric control device 4 ... Air blower 5 ... External load 11 ... Fuel supply line 12 ... Fuel discharge line 13 ... Oxidant supply line 14 ... Oxidant discharge line 15 ... Fuel electrode inlet valve 16 ... Fuel electrode outlet valve 17 ... Oxidant electrode inlet valve 18 ... Oxidant electrode outlet valve 31 ... Inverter 32 ... Control device 33 ... DC-DC converter 100 ... System control device

Claims (7)

In a method for starting a fuel cell power generation system including a fuel cell stack including a fuel electrode and an oxidant electrode,
A starting method of a fuel cell power generation system comprising an operation of reducing an oxidant pole potential gradient in a cell plane accompanying the start of oxidant supply at the time of start-up in a power generation start process of the fuel cell power generation system. A fuel cell stack configured by stacking a plurality of unit cells each having a fuel electrode and an oxidant electrode arranged with an electrolyte interposed therebetween, and a fuel supply device and an oxidant supply that respectively supply fuel and oxidant to the fuel cell stack In a starting method of a fuel cell power generation system comprising an apparatus and an electric control device for controlling a load current of the fuel cell stack,
In the power generation start process of the fuel cell power generation system,
An operation of starting the supply of fuel to the fuel electrode while the supply of air to the oxidant electrode is stopped;
DC current energization operation of flowing a DC current corresponding to a load current from the oxidant electrode to the fuel electrode via an external circuit in a state where fuel is supplied to the fuel electrode;
A method for starting a fuel cell power generation system, comprising performing an operation of supplying an oxidant to the oxidant electrode after the start of the direct current energization operation. A fuel cell stack configured by stacking a plurality of unit cells each having a fuel electrode and an oxidant electrode arranged with an electrolyte interposed therebetween, and a fuel supply device and an oxidant supply that respectively supply fuel and oxidant to the fuel cell stack In a starting method of a fuel cell power generation system comprising an apparatus and an electric control device for controlling a load current of the fuel cell stack,
In the power generation start process of the fuel cell power generation system,
An operation of starting the supply of fuel to the fuel electrode while the supply of air to the oxidant electrode is stopped;
A polarization operation for connecting a DC voltage generating means for applying a DC voltage so that the oxidant electrode is at a higher potential than the fuel electrode in a state where fuel is supplied to the fuel electrode;
A method for starting a fuel cell power generation system, comprising performing an operation of supplying an oxidant to the oxidant electrode after the start of the polarization operation. A fuel cell stack configured by stacking a plurality of unit cells each having a fuel electrode and an oxidant electrode arranged with an electrolyte interposed therebetween, and a fuel supply device and an oxidant supply that respectively supply fuel and oxidant to the fuel cell stack In a program for starting a fuel cell power generation system comprising an apparatus and an electric control device for controlling a load current of the fuel cell stack,
In the power generation start process of the fuel cell power generation system,
An operation of starting the supply of fuel to the fuel electrode while the supply of air to the oxidant electrode is stopped;
DC current energization operation of flowing a DC current corresponding to a load current from the oxidant electrode to the fuel electrode via an external circuit in a state where fuel is supplied to the fuel electrode;
An activation program for a fuel cell power generation system, characterized in that a computer realizes an operation of supplying an oxidant to the oxidant electrode after the start of the direct current energization operation. A fuel cell stack configured by stacking a plurality of unit cells each having a fuel electrode and an oxidant electrode arranged with an electrolyte interposed therebetween, and a fuel supply device and an oxidant supply that respectively supply fuel and oxidant to the fuel cell stack In a program for starting a fuel cell power generation system comprising an apparatus and an electric control device for controlling a load current of the fuel cell stack,
In the power generation start process of the fuel cell power generation system,
An operation of starting the supply of fuel to the fuel electrode while the supply of air to the oxidant electrode is stopped;
Polarization operation for connecting a DC voltage generating means for applying a DC voltage so that the oxidant electrode is held at a higher potential than the fuel electrode in a state where fuel is supplied to the fuel electrode;
An activation program for a fuel cell power generation system, characterized in that a computer realizes an operation of supplying an oxidant to the oxidant electrode after the start of the polarization operation. A fuel cell stack configured by stacking a plurality of unit cells each having a fuel electrode and an oxidant electrode arranged with an electrolyte interposed therebetween, and a fuel supply device and an oxidant supply that respectively supply fuel and oxidant to the fuel cell stack In a fuel cell power generation system comprising an apparatus and an electric control device for controlling a load current of the fuel cell stack,
The electric control device includes a load operation mode in which electric energy obtained by the fuel cell stack is supplied to an external load, and a non-power generation of the fuel cell stack via a power circuit AC power source as a power source from the oxidizer electrode via an external circuit And having a current source mode for flowing a direct current to the fuel electrode,
In a state where supply of air to the oxidant electrode is stopped, fuel supply to the fuel electrode is started, and the electric control device is set to the current source mode so that the fuel from the oxidant electrode via an external circuit is supplied. When a preset holding time elapses after a DC voltage equivalent to a load current is passed through the pole and the unit cell voltage with respect to the fuel pole reaches a preset load operation start voltage, the electric control device Is configured to switch to load operation mode,
A fuel cell power generation system configured to start supply of an oxidant to the oxidant electrode after the time when the electric control device is switched to the load operation mode. A fuel cell stack configured by stacking a plurality of unit cells each having a fuel electrode and an oxidant electrode arranged with an electrolyte interposed therebetween, and a fuel supply device and an oxidant supply that respectively supply fuel and oxidant to the fuel cell stack In a fuel cell power generation system comprising an apparatus and an electric control device for controlling a load current of the fuel cell stack,
The electric control device includes a load operation mode in which electric energy obtained in the fuel cell stack is supplied to an external load, and an arbitrary DC voltage is applied to the fuel cell stack using a system AC power source as a power source when the fuel cell stack is not generating power. DC voltage source mode to apply and polarize,
In a state where supply of air to the oxidant electrode is stopped, supply of fuel to the fuel electrode is started, the electric control device is set to the DC voltage source mode, and a DC voltage is applied to the oxidant electrode, After the cell voltage with respect to the fuel electrode reaches a preset load operation start voltage, when the preset holding time has elapsed, the electric control device is configured to switch to the load operation mode,
A fuel cell power generation system configured to start supply of an oxidant to the oxidant electrode after the time when the electric control device is switched to the load operation mode.

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