JP2003142134A - Fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell system capable of making a quick start and decreasing deterioration of an electrolyte film. SOLUTION: The fuel cell system is composed of an air supply pipe 20 through which the air flows and which is connected with the oxygen electrode side gas passage 11 of the fuel cell 10, a hydrogen supply pipe 21 which is furnished with a reformer 30 to produce a fuel gas chiefly containing hydrogen from a crude gas and is connected with the hydrogen electrode side gas passage 12 of the fuel cell 10, and a mixing means 80 connected with understream of the air supply pipe 20 and hydrogen supply pipe 21 about the reformer 10, wherein the mixing means 80 mixes the air in the air supply pipe 20 with the fuel gas in the hydrogen supply pipe 21 and feeds the mixture to the fuel cell 10 in order to generate an oxidating reaction of the hydrogen in the fuel gas on an electrode catalyst at the time of starting operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell system, and more particularly to a startup control measure.

[0002]

2. Description of the Related Art Conventionally, Japanese Patent Laid-Open No. 2000-251914 has been proposed.
As disclosed in the publication, there is known a fuel cell system in which a source gas is reformed by a reformer to generate a fuel gas, and the fuel gas is supplied to a fuel cell to obtain electric energy. In the reformer, hydrogen is produced from a raw material gas such as methane or methanol, and carbon monoxide is reduced, whereby a fuel gas containing hydrogen as a main component is obtained. A fuel cell is formed by partitioning an oxygen electrode side and a hydrogen electrode side with an electrolyte membrane, and an oxygen-containing gas is supplied to the oxygen electrode side and a fuel gas is supplied to the hydrogen electrode side. ing. Then, when the fuel gas is sent from the reformer to the hydrogen electrode side of the fuel cell, hydrogen, which is the main component of the fuel gas,
It is possible to obtain electric energy by reacting with oxygen on the electrode catalyst (mainly platinum).

[0003]

In the above fuel cell system, although the carbon monoxide concentration is reduced by the reformer, the fuel gas contains carbon monoxide, so that the operating temperature (for example, , 80 ° C.) or lower, the electrode catalyst of the hydrogen electrode loses its activity due to carbon monoxide poisoning. In the above-disclosed fuel cell system, there is described a method of heating the reformer by a burner or the like at the time of startup, but even with this method, it takes a considerable time to raise the temperature to the operating temperature. Therefore, there is a problem that the fuel gas cannot flow into the fuel cell until the temperature inside the fuel cell reaches the above-mentioned operating temperature, and it takes a considerable time to start up.

Therefore, the temperature of the fuel cell may be raised at the time of start-up operation, but if the temperature is simply raised, the electrolyte membrane will be dried. Therefore, the contraction of the electrolyte membrane due to drying during start-up operation and the expansion of the electrolyte membrane due to wetting during power generation operation are repeated, which causes a problem of accelerating the deterioration of the bonded body of the electrolyte membrane and the electrode.

The present invention has been made in view of the above points, and by making a certain improvement to the fuel cell system,
It is intended to perform quick start-up and reduce deterioration of the bonded body of the electrolyte membrane and the electrode.

[0006]

According to the present invention, the oxygen-containing gas and the fuel gas are mixed and flowed into the fuel cell (10) during the start-up operation.

Specifically, the first solution means is a hydrogen passage provided with an oxygen passage (20) for supplying an oxygen-containing gas and a reformer (30) for producing a hydrogen-based fuel gas from a raw material gas. The oxygen electrode side (11) is divided into the oxygen electrode side (11) and the hydrogen electrode side (12) by the joined body of the electrolyte membrane and the electrode, and the oxygen electrode side (11) is the downstream end of the oxygen passageway (20). Connected to the
To oxidize hydrogen in the fuel gas on the fuel cell (10) whose hydrogen electrode side (12) is connected to the downstream end of the hydrogen passage (21) and on the electrode catalyst of the fuel cell (10) during start-up operation. And a mixing means (80) configured to mix the oxygen-containing gas in the oxygen passage (20) and the fuel gas in the hydrogen passage (21) so as to be able to flow into the fuel cell (10).

A second solving means is the same as the first solving means, wherein the mixing means (80) mixes the mixed gas of the oxygen-containing gas and the fuel gas with the hydrogen electrode side (12) of the fuel cell (10). It is configured to only flow into.

A third solving means is the same as the first solving means, wherein the mixing means (80) mixes the mixed gas of the oxygen-containing gas and the fuel gas with the oxygen electrode side (11) of the fuel cell (10). It is configured to only flow into.

A fourth solving means is the same as the first solving means, wherein the mixing means (80) mixes the mixed gas of the oxygen-containing gas and the fuel gas with the oxygen electrode side (11) of the fuel cell (10). And the hydrogen electrode side (12).

The fifth solving means is the mixing means (80) according to any one of the first to fourth solving means.
Is a mixer (81) for communicating the oxygen passage (20) with the hydrogen passage (21) and a mixer (8) in the oxygen passage (20).
1) oxygen opening / closing mechanisms (88, 89) provided on the upstream side and the downstream side of the connecting portion, and on the upstream side and the downstream side of the connecting portion of the mixer (81) in the hydrogen passage (21). The hydrogen opening / closing mechanism (90, 91) and the oxygen bypass opening / closing mechanism (84) are provided, and the oxygen opening / closing mechanism (88, 89) is provided.
And an oxygen bypass passage (82) connected to the oxygen passage (20) so as to bypass the connecting portion of the mixer (81) and a hydrogen bypass opening / closing mechanism (85). 91) and a hydrogen bypass passage (83) connected to the hydrogen passage (21) so as to bypass the connecting portion of the mixer (81).

A sixth solving means is the mixing means (80) according to any one of the first to fourth solving means.
Is a connection passage (93) for connecting the oxygen passage (20) and the hydrogen passage (21), a connection opening / closing mechanism (94) provided in the connection passage (93), and the oxygen passage (20). The oxygen opening / closing mechanisms (88, 89) respectively provided on the upstream side and the downstream side of the connection portion of the connection passageway (93), and the hydrogen passageway (21).
And a hydrogen opening / closing mechanism (90, 91) provided on the upstream side and the downstream side of the connecting portion of the connecting passage (93).

A seventh solving means is any one of the first to sixth solving means, wherein the mixed gas of the oxygen-containing gas and the fuel gas is supplied to the hydrogen electrode of the fuel cell (10) during the power generation operation. Regeneration control means (10) configured to be able to flow into the side (12)
2) equipped.

The eighth solving means is an oxygen passage (20) for supplying an oxygen-containing gas, a heating means (57) provided in the oxygen passage (20) for heating the oxygen-containing gas, and the oxygen. A humidifying means (49) provided in the passage (20) for humidifying the oxygen-containing gas, and a hydrogen passage (21) provided with a reformer (30) for producing a hydrogen-based fuel gas from a raw material gas;
While being divided into an oxygen electrode side (11) and a hydrogen electrode side (12) by a joined body of an electrolyte membrane and an electrode, the oxygen electrode side (11) is a heating means (57) and a humidifier in the oxygen passage (20). The fuel cell (10) is connected to the downstream side of the means (49), and the hydrogen electrode side (12) is connected to the downstream side of the reformer (30) in the hydrogen passage (21).

A ninth solving means is the heating means (57) in the oxygen passage (20) according to the eighth solving means.
And the oxygen passage (20), which is connected to the downstream side of the humidifying means (49) and the downstream side of the reformer (30) in the hydrogen passage (21).
The mixing means (80) is configured to be able to mix the oxygen-containing gas and the fuel gas in the hydrogen passage (21).

A tenth solving means is the same as the ninth solving means, wherein the mixing means (80) mixes the mixed gas of the oxygen-containing gas and the fuel gas with the hydrogen electrode side (12) of the fuel cell (10).
It is configured to only flow into.

An eleventh solving means is the ninth solving means, wherein the mixing means (80) mixes the mixed gas of the oxygen-containing gas and the fuel gas with the oxygen electrode side (11) of the fuel cell (10).
It is configured to only flow into.

A twelfth solving means is the same as the ninth solving means, wherein the mixing means (80) mixes the mixed gas of the oxygen-containing gas and the fuel gas with the oxygen electrode side (11) of the fuel cell (10).
And the hydrogen electrode side (12).

Further, a thirteenth solving means is the mixing means (8) according to any one of the ninth to twelfth solving means.
0) is provided on the upstream side and the downstream side of the mixer (81) for connecting the oxygen passage (20) and the hydrogen passage (21), and the connection part of the mixer (81) in the oxygen passage (20). Oxygen switching mechanism (88, 89), the hydrogen switching mechanism (90, 91) provided on the upstream side and the downstream side of the connection part of the mixer (81) in the hydrogen passage (21), and the oxygen bypass An opening / closing mechanism (84) is provided, and the oxygen opening / closing mechanism (88,8
9) and an oxygen bypass passage (82) connected to the oxygen passage (20) so as to bypass the connection portion of the mixer (81).
And a hydrogen bypass opening / closing mechanism (85), which is connected to the hydrogen passage (21) so as to bypass the connection between the hydrogen opening / closing mechanism (90, 91) and the mixer (81). 83) and are configured.

A fourteenth solving means is the mixing means (8) according to any one of the ninth to twelfth solving means.
0) is a connection passage (93) for connecting the oxygen passage (20) and the hydrogen passage (21), a connection opening / closing mechanism (94) provided in the connection passage (93), and the oxygen passage (20). In the connection passage (93), the oxygen opening / closing mechanisms (88, 89) respectively provided on the upstream side and the downstream side of the connection portion, and the hydrogen passage (2
The hydrogen opening / closing mechanisms (90, 91) are provided on the upstream side and the downstream side of the connection portion of the connection passage (93) in 1), respectively.

A fifteenth solving means is the fuel cell (10) according to any one of the ninth to fourteenth solving means, wherein the mixed gas of the oxygen-containing gas and the fuel gas is supplied during the power generation operation.
And a regeneration control means (102) configured to be able to flow into the hydrogen electrode side (12).

The sixteenth solution means is provided in the fifth or thirteenth solution means at the upstream side of the connecting portion of the mixer (81) in the oxygen passage (20) when the operation is stopped. The oxygen opening / closing mechanism (88) and the hydrogen opening / closing mechanism (91) provided on the downstream side of the connection part of the mixer (81) in the hydrogen passage (21) are opened, and the mixer in the oxygen passage (20) is opened. The oxygen switching mechanism (89) provided on the downstream side of the connection part of (81) and the mixer (81) in the hydrogen passage (21).
A hydrogen opening / closing mechanism (90) provided on the upstream side of the connection part of
A stop control means (103) for closing the oxygen bypass opening / closing mechanism (84) and the hydrogen bypass opening / closing mechanism (85) is provided.

The seventeenth solving means is provided in the fifth or thirteenth solving means in the hydrogen passage (21) downstream of the connecting portion of the mixer (81) when the operation is stopped. Hydrogen opening / closing mechanism (91) and oxygen opening / closing mechanism (88,8
9) is opened, and a hydrogen opening / closing mechanism (90), an oxygen bypass opening / closing mechanism (84), and a hydrogen bypass opening / closing mechanism provided on the upstream side of the connection part of the mixer (81) in the hydrogen passage (21). Stop control means (103) for closing (85) and is provided.

The eighteenth solution means is provided in the sixth or fourteenth solution means at the upstream side of the connection portion of the connection passage (93) in the oxygen passage (20) when the operation is stopped. The oxygen opening / closing mechanism (88), the hydrogen opening / closing mechanism (91) provided on the downstream side of the connecting portion of the connecting passage (93) in the hydrogen passage (21), and the connecting opening / closing mechanism (94) are opened. The oxygen opening / closing mechanism (89) provided on the downstream side of the connecting portion of the connecting passage (93) in the oxygen passage (20) and the upstream side of the connecting portion of the connecting passage (93) on the hydrogen passage (21). A stop control means (103) for closing the hydrogen opening / closing mechanism (90) is provided.

The nineteenth solution means is provided in the sixth or fourteenth solution means at the downstream side of the connection portion of the connection passage (93) in the hydrogen passage (21) when the operation is stopped. Hydrogen opening / closing mechanism (91) and oxygen opening / closing mechanism (8
8,89) and the connection opening / closing mechanism (94) are opened, and the hydrogen opening / closing mechanism (90) provided upstream of the connection portion of the connection passage (93) in the hydrogen passage (21) is closed. Means (103) are provided.

That is, in the first solution, the oxygen-containing gas flows through the oxygen passage (20) while the reformer (3
Hydrogen-based fuel gas produced from the raw material gas by (0) flows through the hydrogen passage (21). During the start-up operation, the mixing means (80) mixes the oxygen-containing gas in the oxygen passage (20) with the fuel gas in the hydrogen passage (21). Then, the mixed gas mixture flows into the fuel cell (10). Fuel cells (10)
Inside, oxygen and hydrogen in the mixed gas react with each other on the electrode catalyst to generate heat and generate steam. Therefore,
The inside of the fuel cell (10) is directly heated by this reaction heat to raise its temperature and is directly humidified by this steam.

In the second solving means, the first means is used.
In the solution, the mixed gas of the oxygen-containing gas and the fuel gas is supplied to the hydrogen electrode side (1) of the fuel cell (10) during the start-up operation.
Inflow only to 2). Then, hydrogen and oxygen in the mixed gas react with each other on the electrode catalyst on the hydrogen electrode side (12) to generate heat and generate water vapor. Therefore, the fuel cell (1
The inside of (0) is directly heated to raise the temperature and be humidified.

Further, in the third solving means, the first
In the solution, the mixed gas of the oxygen-containing gas and the fuel gas is supplied to the oxygen electrode side (1
Inflow only to 1). Then, hydrogen and oxygen in the mixed gas react on the electrode catalyst on the oxygen electrode side (11) to generate heat and generate water vapor. Therefore, the fuel cell (1
The inside of (0) is directly heated to raise the temperature and be humidified.

Further, in the fourth solving means, the first
In the solution, the mixed gas of the oxygen-containing gas and the fuel gas is supplied to the oxygen electrode side (1) of the fuel cell (10) during the start-up operation.
1) and the hydrogen electrode side (12). Then, hydrogen and oxygen in the mixed gas react on the electrode catalysts on both sides to generate heat and generate water vapor. Therefore, the inside of the fuel cell (10) is directly heated to be heated and humidified.

Further, in the fifth solving means, the first
In any one of the fourth to fourth means, the oxygen-containing gas and the fuel gas are mixed in the mixer (81) connected to the oxygen passage (20) and the hydrogen passage (21) during the start-up operation. Then, the mixed gas flows into the fuel cell (10). In the fuel cell (10), hydrogen and oxygen in the mixed gas react on the electrode catalyst to generate heat and generate water vapor. Therefore, the inside of the fuel cell (10) is directly heated to be heated and humidified.

In the sixth solving means, the first
In any one of the fourth to fourth means, the connection opening / closing mechanism (94) is opened during the start-up operation, and the oxygen-containing gas and the fuel gas are mixed in the connection passage (93). Then, the mixed gas flows into the fuel cell (10). In the fuel cell (10), hydrogen and oxygen in the mixed gas react on the electrode catalyst to generate heat and generate water vapor. Therefore, the inside of the fuel cell (10) is directly heated to be heated and humidified.

In the seventh solving means, the first
In any one of the sixth to sixth means, during the power generation operation, in order to desorb carbon monoxide adsorbed on the electrode catalyst, to humidify the electrolyte membrane, or to raise the fuel cell (10). Regeneration control means (10
2) mixes the oxygen-containing gas and the fuel gas, and causes the mixed gas to flow into the hydrogen electrode side (12) of the fuel cell (10).

In the eighth solving means, the oxygen-containing gas flows through the oxygen passage (20) and is heated by the heating means (57) and humidified by the humidifying means (49) during the start-up operation. Then, the oxygen-containing gas that has been heated and humidified flows into the fuel cell (10), and the inside of the fuel cell (10) is heated and humidified. Therefore,
The inside of the fuel cell (10) is directly heated to raise the temperature and be humidified.

In the ninth solving means, the eighth means is used.
In the solution, the mixing means (80) is an oxygen passage (20).
Of the oxygen-containing gas and the fuel gas in the hydrogen passage (21) are mixed.

Further, in the tenth solving means, in the ninth solving means, the mixed gas of the oxygen-containing gas and the fuel gas flows only into the hydrogen electrode side (12) of the fuel cell (10).

Further, in the eleventh solving means, in the ninth solving means, the mixed gas of the oxygen-containing gas and the fuel gas flows into only the oxygen electrode side (11) of the fuel cell (10).

Further, in the twelfth solving means, in the ninth solving means, the mixed gas of the oxygen-containing gas and the fuel gas is the oxygen electrode side (11) and the hydrogen electrode side (12) of the fuel cell (10). ) Flow into.

Further, in the thirteenth solving means, in any one of the ninth to twelfth solving means, the oxygen-containing gas and the fuel gas are supplied to the oxygen passage (20) and the hydrogen passage (2
It is mixed in the mixer (81) connected to 1). And
The mixed gas flows into the fuel cell (10).

Further, in the fourteenth solving means, in any one of the ninth to twelfth solving means, the connection opening / closing mechanism (94) is opened, and the oxygen-containing gas and the fuel gas are connected to the connecting passageway (93). ) Is mixed. Then, the mixed gas flows into the fuel cell (10).

In addition, in the fifteenth solving means, in any one of the ninth to fourteenth solving means, in order to desorb carbon monoxide adsorbed on the electrode catalyst during power generation operation, or In order to humidify and heat the inside of the fuel cell (10), a regeneration control means (102) mixes an oxygen-containing gas with a fuel gas, and mixes the mixed gas with the hydrogen electrode side of the fuel cell (10). Flow into (12).

Further, in the sixteenth solution means, in the fifth or thirteenth solution means, when the operation is stopped, the oxygen-containing gas flows into the mixer (81) and then the hydrogen passage (21). Flow into the hydrogen electrode side (12) of the fuel cell (10). Then, on the hydrogen electrode side (12) of the fuel cell (10), the residual hydrogen is discharged together with the oxygen-containing gas, so that the electromotive force rapidly decreases.

Further, in the seventeenth solving means, in the fifth or thirteenth solving means, when the operation is stopped, the oxygen-containing gas flows into the mixer (81), and then the oxygen passage (20). And the hydrogen passage (21), and flows into the oxygen electrode side (11) and the hydrogen electrode side (12) of the fuel cell (10). Then, on the hydrogen electrode side (12) of the fuel cell (10), the residual hydrogen is discharged together with the oxygen-containing gas, so that the electromotive force rapidly decreases.

Further, in the eighteenth solution means, in the sixth or fourteenth solution means, when the operation is stopped, the oxygen-containing gas flows through the connection passageway (93) and then the hydrogen passageway (21). Flow into the hydrogen electrode side (12) of the fuel cell (10). Then, on the hydrogen electrode side (12) of the fuel cell (10), the residual hydrogen is discharged together with the oxygen-containing gas, so that the electromotive force rapidly decreases.

In the nineteenth solution means, in the sixth or fourteenth solution means, when the operation is stopped, the oxygen-containing gas flows through the connection passageway (93) and then the oxygen passageway (20). And the hydrogen passage (21), and flows into the oxygen electrode side (11) and the hydrogen electrode side (12) of the fuel cell (10). Then, on the hydrogen electrode side (12) of the fuel cell (10), the residual hydrogen is discharged together with the oxygen-containing gas, so that the electromotive force rapidly decreases.

[0045]

As described above, according to the first to seventh and sixteenth to nineteenth solutions, the oxygen-containing gas in the oxygen passage (20) and the fuel gas in the hydrogen passage (21) are mixed during the start-up operation. Since it is made to flow into the fuel cell (10), heat is generated by the oxidation reaction of hydrogen in the fuel cell (10), and steam is generated. As a result, it is possible to perform humidification while raising the temperature inside the fuel cell (10) without separately providing a heating means and a humidifying means for the fuel cell (10). Therefore, it is possible to quickly raise the temperature inside the fuel cell (10) to the operating temperature during start-up operation, prevent the electrolyte membrane from drying, and suppress deterioration of the electrolyte membrane. . In addition, since carbon monoxide contained in the fuel gas reacts with oxygen in the mixed gas or reacts with the generated water vapor, even if the fuel gas is flowed before the inside of the fuel cell (10) reaches the operating temperature. The electrode catalyst is not poisoned by carbon monoxide. Therefore, the fuel gas can flow into the fuel cell (10) even before the operating temperature is reached, and the bypass passage that prevents high concentration carbon monoxide from flowing into the fuel cell (10) during the start-up operation. Is unnecessary, and the configuration can be simplified.

According to the fourth and twelfth solving means, since the mixed gas is caused to flow into both electrodes of the fuel cell (10), no electromotive force is generated during this period. Therefore, for example, carbon corrosion can be suppressed when the bipolar plate is made of a carbon plate.

According to the fifth and thirteenth solving means, the mixing means (80) includes the mixer (81) and the opening / closing mechanism (88, 8).
9,90,91), the oxygen-containing gas and the fuel gas can be reliably mixed. Moreover, since the bypass passages (82, 83) are provided, it is possible to reliably prevent the oxygen-containing gas and the fuel gas from being mixed during the power generation operation.

According to the sixth and fourteenth solving means, the mixing means (80) is connected to the connection passageway (93) and the opening / closing mechanism (8).
8,89,90,91), the oxygen-containing gas and the fuel gas can be reliably mixed.
Further, since the connection opening / closing mechanism (94) is provided in the connection passageway (93), it is possible to reliably prevent the oxygen-containing gas and the fuel gas from being mixed during the power generation operation.

Further, according to the seventh and fifteenth solving means, since the oxygen-containing gas can be made to flow into the hydrogen electrode side (12) even during the power generation operation, the hydrogen electrode is generated during the power generation operation. Even if carbon monoxide is adsorbed on the side (12) electrode catalyst, the adsorbed carbon monoxide can be desorbed. As a result, it is possible to prevent the power generation performance from decreasing.

According to the eighth solving means, since the heating means (57) for heating the oxygen-containing gas and the humidifying means (49) for humidifying the oxygen-containing gas are provided at the time of the start-up operation, the reliability is ensured. It is possible to humidify the inside of the fuel cell (10) while raising the temperature. Therefore, it is possible to quickly raise the temperature inside the fuel cell (10) to the operating temperature during the startup operation, prevent the electrolyte membrane from drying, and prevent the electrolyte membrane from deteriorating.

Further, according to the ninth means for solving the problems, since the means (80) for mixing the oxygen-containing gas in the oxygen passage (20) and the fuel gas in the hydrogen passage (21) is provided, the fuel cell ( The mixed gas can be flowed into the inside of 10). Therefore, for example, when the mixed gas is caused to flow in during the start-up operation, the temperature inside the fuel cell (10) can be raised more rapidly than in the fuel cell system according to the eighth means.

According to the sixteenth and eighteenth means for solving the problems, the oxygen-containing gas is allowed to flow into the hydrogen electrode side (12) of the fuel cell (10) when the operation is stopped, so that the reaction gas is purged. It is possible to quickly and surely perform it, and it is possible to quickly reduce the electromotive force. Further, by rapidly reducing the electromotive force, useless power generation can be prevented, and deterioration of the fuel cell (10) can be prevented. Further, when the operation is stopped, the oxygen-containing gas is supplied to the hydrogen electrode side (12).
Since it is made to flow into the fuel cell, it is possible to ensure safety and prevent deterioration of the fuel cell (10) due to carbon corrosion. Further, since carbon monoxide adsorbed on the electrode catalyst during the power generation operation can be desorbed when the operation is stopped, it is possible to suppress performance deterioration due to carbon monoxide and maintain stable power generation performance. Further, since the inside of the fuel cell (10) does not have a negative pressure when the operation is stopped, it is possible to prevent the exhaust gas from flowing back.

According to the seventeenth and nineteenth means for solving the problems, the oxygen-containing gas is allowed to flow into both sides (11, 12) of the fuel cell (10) when the operation is stopped. Can be quickly performed, and the electromotive force can be quickly and reliably reduced. Further, by rapidly reducing the electromotive force, useless power generation can be prevented, and deterioration of the fuel cell (10) can be prevented. Further, when the operation is stopped, the oxygen-containing gas is supplied to both electrodes (11,1
2) Since it is made to flow in, it is possible to ensure safety and prevent deterioration of the fuel cell (10) due to carbon corrosion. Further, since carbon monoxide adsorbed on the electrode catalyst during the power generation operation can be desorbed when the operation is stopped, it is possible to suppress performance deterioration due to carbon monoxide and maintain stable power generation performance.
Further, since the inside of the fuel cell (10) does not have a negative pressure when the operation is stopped, it is possible to prevent the exhaust gas from flowing back.

[0054]

Embodiment 1 of the present invention will be described in detail below with reference to the drawings.

As shown in FIG. 1, the fuel cell system according to the first embodiment comprises a fuel cell (10), a reformer (30), a mixing means (80) and a controller (100). Further, this fuel cell system is provided with a water circulation path (65) and constitutes a so-called cogeneration system.

The fuel cell (10) is of a solid polymer electrolyte type. In this fuel cell (10), a unit cell is constructed by forming electrodes by dispersing catalyst particles on both sides of an electrolyte membrane made of a fluorine-based polymer film. This electrode catalyst mainly uses platinum.
One of the electrodes on the surface of the electrolyte membrane serves as a hydrogen electrode (anode) and the other serves as an oxygen electrode (cathode). The fuel cell (10) constitutes a stack (assembled cell) in which unit cells are stacked via bipolar plates. The fuel cell (1
Illustration of the structure of 0) is omitted.

In the above fuel cell (10), the bipolar plate and the oxygen electrode of the electrolyte membrane form the gas passage (11) on the oxygen electrode side, and the bipolar plate and the hydrogen electrode of the electrolyte membrane form
A hydrogen electrode side gas passageway (12) is formed. An air supply pipe (20) is connected to the inlet side of the oxygen electrode side gas passageway (11) and an oxygen electrode exhaust pipe (24) is connected to the outlet side thereof. The air supply pipe (20) constitutes an oxygen passage through which air, which is an oxygen-containing gas, flows. On the other hand, a hydrogen supply pipe (21) is connected to the inlet side of the hydrogen electrode side gas passageway (12) and a hydrogen electrode exhaust pipe (25) is connected to the outlet side thereof. The hydrogen supply pipe (21) constitutes a hydrogen passage.

A cooling water circuit (60) is connected to the fuel cell (10). The cooling water circuit (60) is a closed circuit filled with cooling water, and the cooling water pump (61) and the first heat exchanger (71) are connected to each other. By circulating the cooling water in the cooling water circuit (60), the fuel cell (10) is maintained at a predetermined operating temperature.

The air supply pipe (20) has a starting end open to the outside and a downstream end, which is connected to the oxygen electrode side gas passageway (11) of the fuel cell (10). The air supply pipe (20) is provided with a blower (23), a gas heater (52), a first humidifier (40), and a mixing means (80) in this order from the start end to the end.

The air supply pipe (20) has a branch pipe (2
2) is provided. The branch pipe (22) has a starting end connected between the blower (23) and the gas heater (52).

The first humidifier (40) has a water vapor permeable membrane (41). The water vapor permeable film (41) is a water vapor permeable film, and is made of a hydrophilic film such as a polyvinyl alcohol film.

The first humidifier (40) is divided into a first humidified passage (42) and a first exhaust gas passage (43). First humidified side passage (42) and first exhaust gas passage (43)
And are separated by the water vapor permeable membrane (41). An air supply pipe (20) is connected to the first humidification-side passage (42) to introduce air as an oxidant gas.

The reformer (30) includes a hydrogen supply pipe (21).
And is configured to generate a hydrogen-based fuel gas from natural gas supplied as a raw material gas. In the reformer (30), a desulfurizer (31), a gas heater (52), and a second humidifier (45) are arranged in this order along the gas flow.
And a body portion (32). Further, the branch pipe (22) of the air supply pipe (20) is connected between the desulfurizer (31) and the gas heater (52) in the reformer (30).

The desulfurizer (31) is configured to adsorb and remove the sulfur content from the natural gas supplied as the raw material gas.

The second humidifier (45) has a water vapor permeable membrane (46). The water vapor permeable film (46) is a water vapor permeable film, and is composed of a hydrophilic film such as a polyvinyl alcohol film.

The second humidifier (45) is divided into a second humidified passage (47) and a second exhaust gas passage (48). The second humidified side passage (47) and the second exhaust gas passage (48) are separated by the water vapor permeable membrane (46).
The second humidification-side passage (47) is provided between the gas heater (52) and the main body (32) in the reformer (30), and the raw material gas is introduced therein. A hydrogen electrode exhaust pipe (25) is connected to the second exhaust gas passage (48) to introduce the hydrogen electrode exhaust gas discharged as cell exhaust gas from the hydrogen electrode side gas passage (12) of the fuel cell (10). It The second humidifier (45) is for humidifying the raw material gas.

The main body (32) is provided with a reformer (33), a shift converter (34) and a CO remover (35) in order along the gas flow.

The reformer (33) comprises a catalyst which is active for the partial oxidation reaction and a catalyst which is active for the steam reforming reaction. In the reformer (33), methane (CH ₄ ) is generated by partial oxidation reaction and steam reforming reaction.
Hydrogen is generated from natural gas (that is, raw material gas) containing as a main component.

The shift converter (34) is provided with a catalyst that is active in the shift reaction (carbon monoxide shift reaction). In the shift converter (34), the shift reaction reduces carbon monoxide in the gas and simultaneously increases hydrogen.

The CO remover (35) is equipped with a catalyst that is active in the CO selective oxidation reaction. CO remover (35)
Then, CO in the gas is further reduced by the CO selective oxidation reaction. Then, the gas mainly containing hydrogen, which has come out of the CO remover (35), flows through the hydrogen supply pipe (21) as a fuel gas and is supplied to the hydrogen electrode side gas passageway (12) of the fuel cell (10). Has become.

An oxygen electrode exhaust pipe (24) is connected to the first exhaust gas passage (43) of the first humidifier (40). The oxygen electrode exhaust pipe (24) introduces the oxygen electrode exhaust gas discharged as the cell exhaust gas from the oxygen electrode side gas passage (11) of the fuel cell (10). The oxygen electrode exhaust pipe (24) is connected to the first humidifier (4
A heat recovery section (27) is provided on the downstream side of (0). The heat recovery section (27) is connected to the reformer (3) of the reformer (30).
A gas passage formed in the vicinity of 3), the shift converter (34), and the CO remover (35), and configured to recover exhaust heat from the reformer (33) and the like.

The reformer (30) is provided with a combustor (51). The combustor (51) has an oxygen exhaust pipe (2
The end of 4) and the end of the hydrogen exhaust pipe (25) are connected. The combustor (51) is configured to burn the hydrogen remaining in the hydrogen electrode exhaust gas by utilizing the oxygen remaining in the oxygen electrode exhaust gas. In addition, the combustor (51)
The starting end of the combustion gas pipe (26) is connected. The combustion gas pipe (26) has an end open to the outside and a gas heater (52) provided in the middle thereof. The high-temperature combustion gas generated by the combustion of the hydrogen electrode exhaust gas flows through the combustion gas pipe (26) and is discharged outdoors.

The gas heater (52) has an air flow path (5
3), the raw material gas flow path (54), and the combustion gas flow path (55) are defined. The gas heater (52) has an air flow path (53) connected to the air supply pipe (20), and a raw material gas flow path (54) of the gas heater (52) and the desulfurizer (31) in the reformer (30). It is connected between the humidifiers (45) and its combustion gas flow path (55) is connected to the combustion gas pipe (26). The gas heater (52) heats the air as an oxidant gas by exchanging heat between the combustion gas in the combustion gas passage (55) and the air in the air passage (53), and at the same time, The combustion gas of 55) and the raw material gas of the raw material gas flow path (54) are heat-exchanged to heat the raw material gas.

The mixing means (80) is an air supply pipe (20).
And a hydrogen supply pipe (21). Mixing means (8
0) includes a mixer (81), an oxygen bypass passage (82), and a hydrogen bypass passage (83). The mixer (81)
One end is connected between the first humidifier (40) and the fuel cell (10) in the air supply pipe (20), and the other end is connected to the hydrogen supply pipe (2).
It is connected between the CO remover (35) in 1) and the fuel cell (10). The mixer (81) is configured to mix the inflowing air and the fuel gas.

One end of the oxygen bypass passage (82) is connected to the first humidifier (40) and the mixer (8) in the air supply pipe (20).
1) and the other end of the air supply pipe (20) between the mixer (81) and the fuel cell (10). The oxygen bypass passage (82) is provided with an oxygen bypass opening / closing valve (84) that is an oxygen bypass opening / closing mechanism.
The oxygen bypass opening / closing valve (84) is a motor-operated valve whose opening can be adjusted.

One end of the hydrogen bypass passage (83) is a CO remover (35) and a mixer (8) in the hydrogen supply pipe (21).
1) and the other end of the hydrogen supply pipe (21) between the mixer (81) and the fuel cell (10). The hydrogen bypass passage (83) is provided with a hydrogen bypass opening / closing valve (85) which is a hydrogen bypass opening / closing mechanism.

The mixing means (80) includes a first oxygen on-off valve (88) and a second oxygen on-off valve (89) which are oxygen on-off mechanisms.
It is provided with a first hydrogen opening / closing valve (90) and a second hydrogen opening / closing valve (91) which are hydrogen opening / closing mechanisms.

The first oxygen on-off valve (88) is provided downstream of the connecting portion of the oxygen bypass passage (82) in the air supply pipe (20) and upstream of the connecting portion of the mixer (81). There is. The first oxygen on-off valve (88) is composed of an electric valve whose opening can be adjusted. The second oxygen on-off valve (89) is provided on the downstream side of the connection part of the mixer (81) in the air supply pipe (20) and on the upstream side of the connection part of the oxygen bypass passage (82). That is, the oxygen bypass passage (82) is connected to the air supply pipe (20) so as to bypass the connection portion of the oxygen on-off valves (88, 89) and the mixer (81).

The first hydrogen on-off valve (90) is provided on the downstream side of the connection part of the hydrogen bypass passage (83) in the hydrogen supply pipe (21) and on the upstream side of the connection part of the mixer (81). There is. The second hydrogen on-off valve (91) is provided on the downstream side of the connection part of the mixer (81) in the hydrogen supply pipe (21) and on the upstream side of the connection part of the hydrogen bypass passage (83). That is,
The hydrogen bypass passage (83) is connected to the hydrogen supply pipe (21) so as to bypass the connection between the hydrogen on-off valves (90, 91) and the mixer (81).

The water circulation path (65) is a closed circuit filled with heat transfer water. In the water circulation path (65), a circulation pump (66), a first heat exchanger (71), a second heat exchanger (74), and a hot water storage tank (67) in the circulation direction of the heat transfer water. Are provided in order. The heat transfer water circulating in the water circulation path (65) is heated by the first heat exchanger (71) and the second heat exchanger (74) and becomes hot water and is stored in the hot water storage tank (67).
The hot water in the hot water storage tank (67) is supplied to hot water as needed.

In the first heat exchanger (71), a cooling water passage (72) and a water passage (73) are defined. In the first heat exchanger (71), the cooling water channel (72) is connected to the cooling water circuit (60), and the water channel (73) is the water circulation channel (65).
It is connected to the. The first heat exchanger (71) is configured to exchange heat between the cooling water in the cooling water channel (72) and the heat transfer water in the water channel (73).

A combustion gas passage (75) and a water passage (76) are defined in the second heat exchanger (74). Second
In the heat exchanger (74), the combustion gas passage (75) is connected to the combustion gas pipe (26), and the water passage (76) is the water circulation passage (6).
5) connected to. The second heat exchanger (74) is configured to exchange heat between the combustion gas in the combustion gas passage (75) and the heat transfer water in the water passage (76).

The controller (100) includes a start control section (101) which is a start control means, a reproduction control section (102) which is a reproduction control section, and a stop control section (1) which is a stop control section.
03) and.

The start control section (101) opens both oxygen on-off valves (88, 89) and both hydrogen on-off valves (90, 91) at the time of starting, and at the same time, opens the oxygen bypass on-off valve (84) and the hydrogen bypass. The on-off valve (85) is closed to perform a start-up operation. Start control unit is a fuel cell (10)
It is configured to perform a start-up operation until the inside temperature reaches an operating temperature, for example, 80 ° C., and when the temperature inside the fuel cell (10) reaches the operating temperature, switch to the power generation operation.

In the start-up operation, the mixed gas of air and fuel gas flows into the gas passages (11, 12) on both sides of the fuel cell (10), and oxygen and hydrogen are generated on the electrode catalyst in the fuel cell (10). React to generate heat and generate steam. Then, the inside of the fuel cell (10) is heated to an operating temperature while being humidified. In other words, when power is generated below the operating temperature, the electrode catalyst is poisoned by carbon monoxide in the fuel gas and loses its activity. Therefore, the start operation is performed before power generation and the fuel cell (10)
The inside is heated to the operating temperature. Also, if the temperature inside the fuel cell (10) is simply raised, the electrolyte membrane will dry and shrink. Therefore, by preventing the dryness even during start-up operation, expansion due to wetness during power generation and shrinkage due to dryness will occur. It is designed to prevent deterioration due to repetition of. Further, since the electrolyte membrane may be destroyed due to an increase in pH value when dried, it is possible to prevent the electrolyte membrane from being destroyed by humidifying the inside of the fuel cell during the start-up operation. Further, by performing the start-up operation in which the mixed gas is made to flow, the carbon monoxide adsorbed on the electrode catalyst of the hydrogen electrode can be desorbed from the electrode catalyst.

The regeneration control section (102), when regenerating the electrode catalyst of the hydrogen electrode during the power generation operation, has the first oxygen on-off valve (88), the oxygen bypass on-off valve (84) and the both hydrogen on-off valves (90, 90). 91) is opened and the second oxygen on-off valve (8
9) and the hydrogen bypass on-off valve (85) are closed to perform a regeneration operation. In regenerative driving,
Since the mixed gas flows into the hydrogen electrode side gas passage (12) of the fuel cell (10), carbon monoxide adsorbed on the electrode catalyst of the hydrogen electrode is desorbed from the electrode catalyst during the power generation operation. Further, the regeneration control unit (102) is configured to perform a regeneration operation in order to humidify or increase the temperature inside the fuel cell (10). That is, since the exothermic reaction occurs when the mixed gas flows in, the regeneration control unit (102) causes the mixed gas to flow in because the temperature inside the fuel cell (10) rises and water is generated and humidified. It has become.

The stop control section (103) opens both the oxygen on-off valves (88, 89) and the second hydrogen on-off valve (91) when stopping the operation, and at the same time, the first hydrogen on-off valve (90). The bypass on-off valve (84) and the hydrogen bypass on-off valve (85) are closed and the operation is stopped after performing a stop operation for a predetermined time. In the stop operation, since air flows into the gas passages (11, 12) on the both electrodes side, hydrogen remaining in the gas passages (12) on the hydrogen electrode side is discharged, and the electromotive force is rapidly lowered. Further, in the stop operation, since air flows into the hydrogen electrode side gas passage (12) of the fuel cell (10),
During the power generation operation, carbon monoxide adsorbed on the electrode catalyst of the hydrogen electrode is desorbed and the electrode catalyst is regenerated.

-Driving operation-Driving operation of the fuel cell system in the starting operation, the power generating operation, the regenerating operation and the stopping operation will be described.

First, the driving operation of the starting operation will be described. In the start-up operation, both oxygen on-off valves (88, 89) and both hydrogen on-off valves (90, 91) are opened, and the oxygen bypass on-off valve (84) and hydrogen bypass on-off valve (85) are closed. Air as an oxidant gas flows into the air supply pipe (20), and raw material gas flows into the hydrogen supply pipe (21). Natural gas containing methane as a main component is used as a raw material gas.

Part of the air flowing into the air supply pipe (20) is branched into the branch pipe (22), while the remaining air is the air flow path (53) of the gas heater (52) and the first humidifier. After passing through the first humidified side passageway (42) of (40), it flows into the mixer (81). During the startup operation, the air in the air supply pipe (20) is not heated much by the gas heater (52) and is not humidified much by the first humidifier (40).

On the other hand, the raw material gas flowing into the hydrogen supply pipe (21) is introduced into the desulfurizer (31), and the sulfur content contained in the raw material gas is removed. Then, after merging with the air flowing in from the branch pipe (22), the raw material gas flow path (54) of the gas heater (52), the second humidified side passage (47) of the second humidifier (45),
It passes through a reformer (33), a shift converter (34), and a CO remover (35).

In the reformer (33), a partial oxidation reaction of methane and a steam reforming reaction are carried out to produce hydrogen and carbon monoxide. The reacted gas flowing out from the reformer (33) is sent to the shift converter (34). In this gas, steam that has not been used in the steam reforming reaction remains. Transformer (3
In 4), a shift reaction is performed, and carbon monoxide decreases and hydrogen increases at the same time. The gas emitted from the shift converter (34) is introduced into the CO remover (35). The gas sent from the shift converter (34) to the CO remover (35) contains hydrogen as a main component, but still contains carbon monoxide. CO
In the remover (35), a CO selective oxidation reaction is carried out, carbon monoxide is reduced, and fuel gas is obtained. This fuel gas is sent to the mixer (81).

In the mixer (81), the air in the air supply pipe (20) and the fuel gas in the hydrogen supply pipe (21) are mixed to form a mixed gas. This mixed gas flows through the air supply pipe (20) or the hydrogen supply pipe (21) and flows into the fuel cell (10). Then, the oxygen electrode side gas passage (11) or the hydrogen electrode side gas passage (1
In 2), oxygen and hydrogen in the mixed gas react with each other on the electrode catalyst to generate heat and water vapor is generated. As a result, the inside of the fuel cell (10) is directly heated to rapidly raise the temperature and be humidified. Then, when the temperature in the fuel cell (10) reaches the operating temperature, the start-up operation is terminated and the operation switches to the power generation operation.

In the power generation operation, both oxygen on-off valves (88, 89) and both hydrogen on-off valves (90, 91) are closed, and the oxygen bypass on-off valve (84) and hydrogen bypass on-off valve (85) are opened. It The oxygen bypass opening / closing valve (84) is opened to a predetermined opening degree and the air flow rate is adjusted.

In the power generation operation, part of the air flowing into the air supply pipe (20) is sent to the reformer (30) through the branch pipe (22), and the remaining air is used as an oxidant gas in the gas heater. It is introduced into the air flow path (53) of (52). This air absorbs heat from the combustion gas in the combustion gas passage (55) while flowing through the air passage (53).

The air heated in the gas heater (52) flows into the first humidified side passage (42) of the first humidifier (40). On the other hand, the first exhaust gas passage (43) of the first humidifier (40)
Oxygen electrode exhaust gas is introduced into. Then, the water vapor in the oxygen electrode exhaust gas that has permeated the water vapor permeable membrane (41) is supplied to the air in the first humidified side passageway (42).

The heated and humidified air then flows into the oxygen electrode side gas passage (11) of the fuel cell (10) via the oxygen bypass passage (82). Oxygen electrode side gas passage (1
By humidifying the air introduced into 1) with the first humidifier (40), the electrolyte membrane in the fuel cell (10) is prevented from drying.

On the other hand, in the raw material gas flowing into the hydrogen supply pipe (21), the sulfur content contained in the raw material gas is removed by the desulfurizer (31), and the air from the branch pipe (22) is mixed into the raw material gas. It is introduced into the raw material gas flow path (54) of the heater (52). This raw material gas absorbs heat from the combustion gas in the combustion gas passage (55) while flowing through the raw material gas passage (54).

The source gas heated in the gas heater (52) flows into the second humidified passage (47) of the second humidifier (45). On the other hand, the hydrogen electrode exhaust gas is introduced into the second exhaust gas passage (48) of the second humidifier (45). And
The water vapor in the hydrogen electrode exhaust gas that has permeated the water vapor permeable membrane (46) is supplied to the source gas in the second humidification side passageway (47).

The raw material gas humidified by the second humidifier (45) is introduced into the reformer (33), and hydrogen and carbon monoxide are produced by the partial oxidation reaction of methane and the steam reforming reaction. . The reacted gas flowing out from the reformer (33) is sent to the shift converter (34), and due to the shift reaction, carbon monoxide decreases and hydrogen increases at the same time. The gas discharged from the shift converter (34) is introduced into the CO remover (35) to further reduce carbon monoxide in the gas by the CO selective oxidation reaction. And
The gas from which carbon monoxide has been reduced in the CO remover (35) is supplied as a fuel gas to the hydrogen electrode side gas passage (12) of the fuel cell (10) via the hydrogen bypass passage (83).

In the power generation operation, the fuel cell (10) is
Fuel gas is supplied to the hydrogen electrode side gas passage (12), and air is supplied to the oxygen electrode side gas passage (11). Fuel cells (10)
Generates electricity by using hydrogen in fuel gas as fuel and oxygen in air as an oxidant.

Gas passage (11) on the oxygen electrode side of the fuel cell (10)
Oxygen electrode exhaust gas is discharged as battery exhaust gas from.
This oxygen electrode exhaust gas contains excess oxygen that was not used in the cell reaction. In addition, the oxygen electrode exhaust gas contains water vapor generated by the cell reaction. The oxygen electrode exhaust gas is passed through the oxygen electrode exhaust pipe (24) to the first humidifier (4
It is introduced into the first exhaust gas passage (43) of (0). As described above, the water vapor in the oxygen electrode exhaust gas permeates the water vapor permeable membrane (41) and is supplied to the air in the first humidified side passageway (42).
The oxygen electrode exhaust gas deprived of water vapor in the first humidifier (40) flows through the heat recovery section (27). The oxygen electrode exhaust gas recovers the exhaust heat of the reformer (33), the shift converter (34) and the CO remover (35) in the heat recovery section (27) and is sent to the combustor (51).

On the other hand, the hydrogen electrode exhaust gas is discharged as the cell exhaust gas from the hydrogen electrode side gas passage (12) of the fuel cell (10). In this hydrogen electrode exhaust gas, hydrogen that has not been used in the cell reaction remains. Further, the hydrogen gas exhaust gas contains water vapor generated by the cell reaction. The hydrogen electrode exhaust gas is introduced into the second exhaust gas passage (48) of the second humidifier (45) through the hydrogen electrode exhaust pipe (25). As described above, the water vapor in the hydrogen gas exhaust gas is absorbed by the water vapor permeable membrane (46).
And is supplied to the raw material gas in the second passage (47) to be humidified. The hydrogen electrode exhaust gas deprived of water vapor in the second humidifier (45) is sent to the combustor (51).

The combustor (51) burns hydrogen in the hydrogen electrode exhaust gas by using oxygen in the oxygen electrode exhaust gas. Combustion of this hydrogen electrode exhaust gas produces high-temperature combustion gas. The combustion gas flows through the combustion gas pipe (26) and is introduced into the combustion gas passage (75) of the second heat exchanger (74), and radiates heat to the heat transfer water in the water passage (76).

This heat-dissipated combustion gas is supplied to the gas heater (5
Introduced into the combustion gas channel (55) of 2), the air channel (53)
Heat is further radiated to the air and the raw material gas in the raw material gas flow path (54). Then, the combustion gas exits the combustion gas flow path (55) and is exhausted to the outside.

When the cooling water pump (61) is operated, the cooling water circulates in the cooling water circuit (60). The cooling water discharged from the cooling water pump (61) is sent to the fuel cell (10) and absorbs heat. Due to the heat absorption of this cooling water, the fuel cell (1
0) is maintained at a predetermined operating temperature (for example, about 80 ° C.). The cooling water that has absorbed heat in the fuel cell (10) is introduced into the cooling water passage (72) of the first heat exchanger (71) and radiates heat to the heat transfer water in the water passage (73). The radiated cooling water is sucked into the cooling water pump (61). Then, the cooling water pump (61) again sends the cooling water after heat radiation toward the fuel cell (10), and this circulation is repeated.

When the circulation pump (66) is operated, the heat transfer water circulates in the water circulation passage (65). The heat transfer water flowing out from the bottom of the hot water storage tank (67) is sent to the water flow passage (73) of the first heat exchanger (71) by the circulation pump (66) and absorbs heat from the cooling water of the cooling water flow passage (72). To do.

After that, the heat transfer water is introduced into the water passage (76) of the second heat exchanger (74) and absorbs heat from the combustion gas in the combustion gas passage (75). Then, the heat transfer water discharged from the second heat exchanger (74) is sent back to the hot water storage tank (67) and stored as hot water. The heat transfer water stored as hot water in the hot water storage tank (67) is used for hot water supply.

During the power generation operation, when the electrode catalyst of the hydrogen electrode is regenerated, the regeneration operation is performed. During regeneration operation, the first oxygen on-off valve (88) and oxygen bypass on-off valve (8
4) and both hydrogen on-off valves (90, 91) are opened, and the second oxygen on-off valve (89) and hydrogen bypass on-off valve (85) are closed. Part of the air in the air supply pipe (20) flows through the oxygen bypass passage (82) and flows into the oxygen side gas passage (11) of the fuel cell (10), while the remaining air flows into the mixer (81). Then, it is mixed with the fuel gas flowing from the hydrogen supply pipe (21) to form a mixed gas. This gas mixture is for fuel cells (10)
The carbon monoxide that has flowed into the hydrogen electrode side gas passageway (12) and adsorbed on the electrode catalyst is desorbed. In this way, the electrode catalyst of the hydrogen electrode is regenerated.

Next, the operation of the stopped operation when the operation is stopped will be described. In the stop operation, both the oxygen opening / closing valves (88, 89) and the second hydrogen opening / closing valve (91) are opened, and the first hydrogen opening / closing valve (90), the bypass opening / closing valve (84) and the hydrogen bypass opening / closing valve (85) are also opened. Is closed and operation is performed for a predetermined time.

Part of the air in the air supply pipe (20) flows into the mixer (81), and the remaining air flows into the oxygen electrode side gas passage (11) of the fuel cell. The air flowing into the mixer (81) flows into the hydrogen electrode side gas passage (12). In the hydrogen electrode side gas passageway (12), the air discharges the residual hydrogen, so that the electromotive force rapidly decreases. In the hydrogen electrode side gas passage (12), air desorbs carbon monoxide adsorbed on the electrode catalyst during the power generation operation. Then, the operation is stopped after a predetermined time.

-Effects of First Embodiment- According to the first embodiment, the fuel cell (10) is prepared by mixing the oxygen-containing gas in the oxygen passage (20) and the hydrogen-containing gas in the hydrogen passage (21) during the startup operation. Since it was made to flow into the fuel cell (10), heat is generated by the oxidation reaction of hydrogen in the fuel cell (10),
Steam is generated. As a result, the fuel cell (10) can be provided without separately providing heating means and humidifying means for the fuel cell (10).
Humidification can be performed while raising the temperature inside. Therefore, it is possible to quickly raise the temperature inside the fuel cell (10) to the operating temperature during start-up operation, prevent the electrolyte membrane from drying, and suppress deterioration of the electrolyte membrane. . In addition, since carbon monoxide contained in the fuel gas reacts with oxygen in the mixed gas or reacts with the generated water vapor, even if the fuel gas is flowed before the temperature inside the fuel cell (10) reaches the operating temperature. The electrode catalyst is not poisoned by carbon monoxide. Therefore, the fuel gas can flow into the fuel cell (10) even before the operating temperature is reached, and the bypass passage that prevents the high concentration of carbon monoxide from flowing into the fuel cell (10) during the startup operation. Is unnecessary, and the configuration can be simplified.

Further, during the start-up operation, the fuel cell (1
Since the mixed gas is made to flow into both electrode sides (11, 12) of (0), no electromotive force is generated during this period. Therefore,
For example, when the bipolar plate is made of a carbon plate, carbon corrosion can be suppressed.

Further, since the mixing means (80) is constituted by the mixer (81) and the opening / closing valve (88, 89, 90, 91), the oxygen-containing gas and the fuel gas are surely mixed. You can Moreover, since the bypass passages (82, 83) are provided, it is possible to reliably prevent the oxygen-containing gas and the fuel gas from being mixed during the power generation operation.

Further, since the oxygen-containing gas can be made to flow into the hydrogen electrode side (12) during the power generation operation, carbon monoxide is adsorbed on the electrode catalyst on the hydrogen electrode side (12) during the power generation operation. Also, the adsorbed carbon monoxide can be desorbed. As a result, it is possible to prevent the power generation performance from decreasing.

Further, since the oxygen-containing gas is made to flow into both sides (11, 12) of the fuel cell (10) when the operation is stopped, the reaction gas can be purged quickly and surely and the electromotive force can be reduced. The reduction can be performed quickly and reliably. Further, by rapidly reducing the electromotive force, useless power generation can be prevented, and deterioration of the fuel cell (10) can be prevented. Further, since the oxygen-containing gas is made to flow into both electrode sides (11, 12) when the operation is stopped, safety can be ensured and deterioration of the fuel cell (10) due to carbon corrosion can be prevented. Further, since carbon monoxide adsorbed on the electrode catalyst during the power generation operation can be desorbed when the operation is stopped, it is possible to suppress performance deterioration due to carbon monoxide and maintain stable power generation performance. Further, since the inside of the fuel cell (10) does not have a negative pressure when the operation is stopped, it is possible to prevent the exhaust gas from flowing back.

[0117]

Second Embodiment As shown in FIG. 2, the fuel cell system according to the second embodiment is different from the first embodiment in that the mixing means (80) is replaced with the mixer (81) by the connecting passage (93). Is equipped with.

One end of the connection passageway (93) has an air supply pipe (2
0) is connected between both oxygen on-off valves (88, 89), and the other end is connected between both hydrogen on-off valves (90, 91) in the hydrogen supply pipe. The connection passage (93) is provided with a connection opening / closing valve (94) which is a connection opening / closing mechanism. The connection on-off valve is
It is composed of an electric valve whose opening can be adjusted.

Both bypass passages (82, 83) are omitted.

Activation controller (101) of controller (100)
Is configured to perform a start-up operation in which the both oxygen on-off valves (88, 89), both hydrogen on-off valves (90, 91) and the connection on-off valve (94) are opened when the operation is started. In the startup operation, the opening degree of the connection opening / closing valve (94) is adjusted to a predetermined opening degree. The start-up control unit performs a start-up operation until the temperature inside the fuel cell (10) reaches an operating temperature, for example, 80 ° C., and when the temperature inside the fuel cell (10) reaches the operating temperature, switches to a power generation operation. It is configured. In the power generation operation, the connection opening / closing valve (94) is closed.

The regeneration control section (102), when regenerating the electrode catalyst of the hydrogen electrode during the power generation operation, the first oxygen on-off valve (88), the second oxygen on-off valve (89) and the both hydrogen on-off valves (90). , 9
1) is opened and the regeneration operation is performed by adjusting the opening degree of the connection opening / closing valve (94).

The stop control section (103), when stopping the operation, both oxygen on-off valves (88, 89) and the second hydrogen on-off valve (91).
The connection on-off valve (94) is opened, and the first hydrogen on-off valve (90) is closed to stop the operation after performing a stop operation for a predetermined time.

-Operational Behavior-In the start-up operation, both oxygen on-off valves (88, 89), both hydrogen on-off valves (90, 91) and connection on-off valve (94) are opened to perform operation. Air flowing through the air supply pipe (20) and hydrogen supply pipe (21)
The fuel gas flowing therethrough is mixed by the mixing means (80) to form a mixed gas. This mixed gas flows through the air supply pipe (20) or the hydrogen supply pipe (21) and flows into the fuel cell (10).
Then, in the oxygen electrode side gas passage (11) or the hydrogen electrode side gas passage (12), oxygen and hydrogen in the mixed gas react with each other on the electrode catalyst to generate heat and water vapor is generated. As a result, the inside of the fuel cell (10) is directly heated to rapidly raise the temperature and be humidified.

When the temperature inside the fuel cell reaches the operating temperature, the start-up operation is terminated and the operation switches to the power generation operation. In power generation operation, the connection on-off valve (94) is closed. In the power generation operation, the same operation operation as that of the first embodiment is performed.

During the regeneration operation for regenerating the electrode catalyst of the hydrogen electrode during the power generation operation, the opening degree of the connection opening / closing valve (94) is adjusted to adjust the amount of air flowing into the hydrogen electrode side gas passageway (12). By doing so, the air in the air supply pipe (20) and the fuel gas in the hydrogen supply pipe (21) are mixed by the mixing means (80), flow into the hydrogen electrode side gas passage (12), and the electrode The carbon monoxide adsorbed on the catalyst is desorbed.

At the time of stop operation, both oxygen on-off valves (88,8
9), the second hydrogen on-off valve (91) and the connection on-off valve (94) are opened, and the first hydrogen on-off valve (90) is closed to operate for a predetermined time. The mixed gas flows into the gas passages (11, 12) on both sides of the fuel cell (10), and the gas passages on the hydrogen side (1
In 2), the air in the mixed gas desorbs carbon monoxide adsorbed on the electrode catalyst during power generation operation. Further, in the hydrogen electrode side gas passageway (12), the residual hydrogen is discharged by the inflowing air, so that the electromotive force is rapidly reduced.

-Effect of Second Embodiment- According to the second embodiment, the mixing means (80) is connected to the connecting passageway (9).
3) and the on-off valve (88, 89, 90, 91), the oxygen-containing gas and the fuel gas can be reliably mixed. In addition, the connection opening / closing valve (9
Since 4) is provided, it is possible to reliably prevent the oxygen-containing gas and the fuel gas from being mixed during the power generation operation.

Other configurations, operations and effects are the same as those of the first embodiment.
Is the same as.

[0129]

Third Embodiment As shown in FIG. 3, the fuel cell system according to the third embodiment is different from the first embodiment in that the heating means (57) for heating the air in the air supply pipe (20) during the start-up operation. ) And a humidifying means (49) for humidifying the air.

The heating means (57) is an air supply pipe (20).
Is arranged in close proximity to the gas heater (52) and the first humidifier (40), and is configured to heat the air supply pipe (20). The heating means (57) is for heating the air supplied to the fuel cell (10) during the startup operation.

The humidifying means (49) is the air supply pipe (20).
Is provided between the first humidifier (40) and the mixing means (80). The humidifying means (49) is configured to humidify the air in the air supply pipe (20), for example, by using the steam in the hot water storage tank (67).

Activation controller (101) of controller (100)
Is configured to drive the heating means (57) and the humidifying means (49) during the startup operation. That is, during the start-up operation, the fuel cell (10) is heated and humidified by the air that has been heated and humidified by the heating means (57) and the humidifying means (49).

Unlike the first embodiment, the start control section (101) closes both oxygen on-off valves (88, 89), both hydrogen on-off valves (90, 91) and hydrogen bypass on-off valve (85) during the start-up operation. Along with this, the oxygen bypass opening / closing valve (84) is opened. In other words, the fuel cell (1
Only the air heated to 0) and humidified is the fuel cell (10)
The fuel gas does not flow in.

Further, the start control section (101) is configured to stop the driving of the heating means (57) and the humidifying means (49) when switching from the start operation to the power generation operation.

Further, the start control section (101) closes both oxygen on-off valves (88,89) and both hydrogen on-off valves (90,91) when switching to the power generation operation, and at the same time, the oxygen bypass on-off valve (8).
4) and the hydrogen bypass opening / closing valve (85) are opened. In other words, during power generation operation, each on-off valve
The state is the same as the open / close state during the power generation operation in the first embodiment.

Reproduction control section (102) and stop control section (103)
Has the same configuration as the reproduction control unit (102) and the stop control unit (103) in the first embodiment.

The mixing means (80) in the third embodiment.
Is not for generating the mixed gas during the startup operation, but for generating the mixed gas during the regeneration operation or the stop operation. Therefore, the mixed gas is not generated during the start-up operation.

-Driving operation-During start-up operation, while the heating means (57) and the humidifying means (49) are driven, both oxygen on-off valves (88, 89) and both hydrogen on-off valves (9
0, 91) and the hydrogen bypass opening / closing valve (85) are closed, and the oxygen bypass opening / closing valve (84) is opened. The air in the air supply pipe (20) passes through the gas heater (52) and the vicinity of the heating means (57). At this time, the air supply pipe (20)
The air is heated by the heating means (57). The heated air passes through the first humidifier (40), flows into the humidifying means (49), and is humidified. The air humidified by the humidifying means (49) flows through the oxygen bypass passage (82) and flows into the oxygen electrode side gas passage (11) of the fuel cell (10). The heated and humidified air heats up the inside of the fuel cell (10) while humidifying it. During the start-up operation, the fuel gas in the hydrogen supply pipe (21) does not flow into the fuel cell (10).

When the temperature inside the fuel cell (10) reaches the operating temperature, the start-up operation is terminated and the operation switches to the power generation operation. At this time, the driving of the heating means (57) and the humidifying means (49) is stopped. That is, during the power generation operation, the air in the air supply pipe (20) is heated by the gas heater (52), humidified by the first humidifier (40), and then flows into the fuel cell (10).

Since the driving operation during the power generation operation, the regeneration operation and the stop operation is the same as the driving operation during the power generation operation in the first embodiment, the description thereof will be omitted.

-Effects of the third embodiment- According to the third embodiment, the heating means (57) for heating the oxygen-containing gas and the humidifying means (49) for humidifying the oxygen-containing gas are provided during the start-up operation. In addition, it is possible to perform humidification while surely raising the temperature inside the fuel cell (10). Therefore, it is possible to quickly raise the temperature inside the fuel cell (10) to the operating temperature during the startup operation, prevent the electrolyte membrane from drying, and prevent the electrolyte membrane from deteriorating.

Further, since the mixing means (80) for mixing the oxygen-containing gas of the air supply pipe (20) and the fuel gas of the hydrogen supply pipe (21) is provided, for example, the mixed gas is supplied to the fuel cell (1).
It is possible to regenerate the electrocatalyst of the hydrogen electrode by flowing it into (0).

Other configurations, operations and effects are the same as those of the first embodiment.
Is the same as.

[0144]

Fourth Embodiment In a fuel cell system according to a fourth embodiment, as shown in FIG. 4, unlike the third embodiment, the mixing means (80) has a connecting passage (93) instead of the mixer (81). Is equipped with.

The connection passageway (93) has an air supply pipe (2
0) is connected between both oxygen on-off valves (88, 89), and the other end is connected between both hydrogen on-off valves (90, 91) in the hydrogen supply pipe. The connection passage (93) is provided with a connection opening / closing valve (94) which is a connection opening / closing mechanism. Connection on-off valve (9
4) is composed of an electric valve with adjustable opening.

The start control unit (101) opens both oxygen on-off valves (88, 89) and closes both hydrogen on-off valves (90, 91) and the connection on-off valve (94) during the start-up operation. It is configured.

The regeneration control section (102), when regenerating the electrode catalyst of the hydrogen electrode during the power generation operation, includes a first oxygen on-off valve (88), a second oxygen on-off valve (89) and both hydrogen on-off valves (90). , 9
It is configured to perform regeneration operation in which 1) is opened and the opening degree of the connection opening / closing valve (94) is adjusted.

The stop control section (103), when stopping the operation, both oxygen on-off valves (88, 89) and the second hydrogen on-off valve (91).
The connection on-off valve (94) is opened, and the first hydrogen on-off valve (90) is closed to stop the operation after performing a stop operation for a predetermined time.

Therefore, during the start-up operation, the air in the air supply pipe (20) is heated by the heating means (57) and humidified by the humidifying means (49). Further, during the power generation operation, the air in the air supply pipe (20) is heated by the gas heater (52) and humidified by the first humidifier (40).

Other configurations, actions and effects are the same as those of the second embodiment.
And 3 are the same.

[0151]

Other Embodiments of the Invention In the above-described first and second embodiments, the startup control unit (101) opens the second oxygen on-off valve (89) and the second hydrogen on-off valve (91) during startup operation. Instead, only the second oxygen on-off valve (89) may be opened and the second hydrogen on-off valve (91) may be closed. That is,
A configuration may be adopted in which the mixed gas is caused to flow only into the oxygen electrode side gas passage (11) during the startup operation. In addition, the startup control unit (10
1) is the second oxygen on-off valve (89) and second
Instead of opening the hydrogen opening / closing valve (91), only the second hydrogen opening / closing valve (91) may be opened and the second oxygen opening / closing valve (89) may be closed. That is, the mixed gas may be allowed to flow only into the hydrogen electrode side gas passage (12) during the startup operation. Even with such a configuration, similar effects can be obtained.

Further, in each of the above embodiments, the reproduction control unit (102) and the stop control unit (103) may be omitted. Alternatively, only one of them may be omitted.

Further, in each of the above-mentioned embodiments, the stop control unit (103) causes the air flowing into the mixing means (80) to flow into the gas passages (11, 1) of both electrodes of the fuel cell (10) during the stop operation.
Instead of the structure that flows into 2), the structure may be such that only the hydrogen electrode side gas passage (12) is supplied.

Further, the mixing means (80) may be omitted in the third and fourth embodiments.

Further, in the third embodiment, the startup control section (101) may be configured to control each on-off valve of the mixing means (80) in the same state as in the first embodiment during the startup operation. That is, the startup control unit (101) drives the heating means (57) and the humidifying means (49) during startup operation, while at the same time, both oxygen on-off valves (88,89) and both hydrogen on-off valves (90,91).
May be opened, and the oxygen bypass opening / closing valve (84) and the hydrogen bypass opening / closing valve (85) may be closed. With such a configuration, the temperature in the fuel cell (10) can be raised more quickly without generating electromotive force. Further, during the start-up operation, the mixed gas may flow into the oxygen electrode side gas passage (11) or the hydrogen electrode side gas passage (12).

Further, in the fourth embodiment, the startup control section (101) may be configured to control each on-off valve of the mixing means (80) to a state similar to that of the second embodiment during startup operation. In other words, the start control unit (101) drives the heating means (57) and the humidifying means (49) during start-up operation, while at the same time, both oxygen on-off valves (88,89) and both hydrogen on-off valves (90,91) Alternatively, the connection opening / closing valve (94) may be opened.
With such a configuration, the temperature in the fuel cell (10) can be raised more quickly without generating electromotive force. Further, during the start-up operation, the mixed gas may flow into the oxygen electrode side gas passage (11) or the hydrogen electrode side gas passage (12).

[Brief description of drawings]

FIG. 1 is a piping system diagram showing an overall configuration of a fuel cell system according to a first embodiment.

FIG. 2 is a piping system diagram showing an overall configuration of a fuel cell system according to a second embodiment.

FIG. 3 is a piping system diagram showing an overall configuration of a fuel cell system according to a third embodiment.

FIG. 4 is a piping system diagram showing an overall configuration of a fuel cell system according to a fourth embodiment.

[Explanation of symbols]

(10) Fuel cell (11) Oxygen electrode side gas passage (12) Hydrogen side gas passage (20) Air supply pipe (21) Hydrogen supply pipe (30) Reformer (49) Humidification means (57) Heating means (80) Mixing means (81) Mixer (82) Oxygen bypass passage (83) Hydrogen bypass passage (84) Oxygen bypass valve (85) Hydrogen bypass opening / closing valve (88) First oxygen on-off valve (89) Second oxygen on-off valve (90) 1st hydrogen on-off valve (91) Second hydrogen on-off valve (93) Connection passage (94) Connection on-off valve (102) Playback control section (103) Stop control unit

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01M 8/10 H01M 8/10 F term (reference) 5H026 AA06 CC03 5H027 AA06 BA01 BA16 BA17 BA20 BC12 BC20 DD06 MM02

Claims (19)

[Claims] 1. An oxygen passage (20) for supplying an oxygen-containing gas.
And a hydrogen passage (21) provided with a reformer (30) for producing a fuel gas mainly containing hydrogen from the raw material gas, and an oxygen electrode side (11) and a hydrogen electrode side ( 12), while the oxygen electrode side (11) is connected to the downstream end of the oxygen passage (20), and the hydrogen electrode side (12)
Is connected to the fuel cell (10) connected to the downstream end of the hydrogen passage (21) and the oxygen passage (20) in order to oxidize hydrogen in the fuel gas on the electrode catalyst of the fuel cell (10) during start-up operation. ) The oxygen-containing gas of (1) and the fuel gas of the hydrogen passage (21) are mixed, and a mixing means (80) configured to be able to flow into the fuel cell (10) is provided. 2. The mixing means (80) according to claim 1, wherein the mixed gas of the oxygen-containing gas and the fuel gas is made to flow only into the hydrogen electrode side (12) of the fuel cell (10). A fuel cell system characterized by the above. 3. The mixing means (80) according to claim 1, wherein the mixed gas of the oxygen-containing gas and the fuel gas is made to flow only into the oxygen electrode side (11) of the fuel cell (10). A fuel cell system characterized by the above. 4. The mixing means (80) according to claim 1, wherein the mixed gas of the oxygen-containing gas and the fuel gas is mixed with the oxygen electrode side (11) and the hydrogen electrode side (1) of the fuel cell (10).
A fuel cell system characterized in that it is configured to flow into 2). 5. The mixing means (80) according to any one of claims 1 to 4, wherein the mixing means (80) connects the oxygen passage (20) and the hydrogen passage (21) to each other, and the oxygen passage (80). The oxygen opening / closing mechanism (8) provided on the upstream side and the downstream side of the connecting portion of the mixer (81) in the (20)
8, 89) and the hydrogen switching mechanism (9) provided on the upstream side and the downstream side of the connecting portion of the mixer (81) in the hydrogen passage (21).
0, 91) and an oxygen bypass opening / closing mechanism (84) are connected to the oxygen passage (20) so as to bypass the connecting portion of the oxygen opening / closing mechanism (88, 89) and the mixer (81). An oxygen bypass passage (82) and a hydrogen bypass opening / closing mechanism (85) are provided and connected to the hydrogen opening / closing mechanism (90, 91) and the mixer (81) so as to bypass the connecting portion. And a hydrogen bypass passage (83) that is provided with the fuel cell system. 6. The mixing means (80) according to claim 1, wherein the mixing means (80) includes a connection passage (93) for connecting the oxygen passage (20) and the hydrogen passage (21), and the connection passage. Connection opening / closing mechanism (94) provided in (93)
An oxygen opening / closing mechanism (88, 89) respectively provided on the upstream side and the downstream side of the connection portion of the connection passage (93) in the oxygen passage (20), and the connection passage (93) in the hydrogen passage (21). And a hydrogen opening / closing mechanism (90, 91) respectively provided on the upstream side and the downstream side of the connection part of the fuel cell system. 7. The fuel cell system according to claim 1, wherein a mixed gas of an oxygen-containing gas and a fuel gas can flow into a hydrogen electrode side (12) of a fuel cell (10) during a power generation operation. A fuel cell system comprising: a regeneration control means (102). 8. An oxygen passage (20) for supplying an oxygen-containing gas.
A heating means (57) provided in the oxygen passage (20) for heating the oxygen-containing gas; a humidifying means (49) provided in the oxygen passage (20) for humidifying the oxygen-containing gas; A hydrogen passage (21) provided with a reformer (30) for producing a fuel gas mainly containing hydrogen from an oxygen electrode side (11) and a hydrogen electrode side (12) by a joined body of an electrolyte membrane and an electrode. While being partitioned, the oxygen electrode side (11) is connected to the downstream side of the heating means (57) and the humidifying means (49) in the oxygen passageway (20), and the hydrogen electrode side (12) is the hydrogen passageway (21). And a fuel cell (10) connected to the downstream side of the reformer (30). 9. The reformer (3) according to claim 8, wherein the oxygen passage (20) has a downstream side of the heating means (57) and the humidifying means (49) and the hydrogen passage (21).
And a mixing means (80) that is connected to the downstream side of (0) and is configured to mix the oxygen-containing gas in the oxygen passage (20) and the fuel gas in the hydrogen passage (21). Fuel cell system. 10. The mixing means (80) according to claim 9, is configured to allow the mixed gas of the oxygen-containing gas and the fuel gas to flow only into the hydrogen electrode side (12) of the fuel cell (10). A fuel cell system characterized by the above. 11. The mixing means (80) according to claim 9, wherein the mixed gas of the oxygen-containing gas and the fuel gas is allowed to flow only into the oxygen electrode side (11) of the fuel cell (10). A fuel cell system characterized by the above. 12. The mixing means (80) according to claim 9, wherein the mixed gas of the oxygen-containing gas and the fuel gas is mixed with the oxygen electrode side (11) and the hydrogen electrode side (1) of the fuel cell (10).
A fuel cell system characterized in that it is configured to flow into 2). 13. The mixing means (80) according to any one of claims 9 to 12, wherein the mixing means (80) connects the oxygen passage (20) and the hydrogen passage (21) to each other, and the oxygen passage (80). The oxygen opening / closing mechanism (8) provided on the upstream side and the downstream side of the connecting portion of the mixer (81) in the (20)
8, 89) and the hydrogen switching mechanism (9) provided on the upstream side and the downstream side of the connecting portion of the mixer (81) in the hydrogen passage (21).
0, 91) and an oxygen bypass opening / closing mechanism (84) are connected to the oxygen passage (20) so as to bypass the connecting portion of the oxygen opening / closing mechanism (88, 89) and the mixer (81). An oxygen bypass passage (82) and a hydrogen bypass opening / closing mechanism (85) are provided and connected to the hydrogen opening / closing mechanism (90, 91) and the mixer (81) so as to bypass the connecting portion. And a hydrogen bypass passage (83) that is provided with the fuel cell system. 14. The mixing means (80) according to claim 9, wherein the mixing means (80) connects the oxygen passage (20) and the hydrogen passage (21) to each other, and the connection passage (93). Connection opening / closing mechanism (94)
An oxygen opening / closing mechanism (88, 89) respectively provided on the upstream side and the downstream side of the connection portion of the connection passage (93) in the oxygen passage (20), and the connection passage (93) in the hydrogen passage (21). And a hydrogen opening / closing mechanism (90, 91) respectively provided on the upstream side and the downstream side of the connection part of the fuel cell system. 15. The fuel cell system according to claim 9, wherein the mixed gas of the oxygen-containing gas and the fuel gas can flow into the hydrogen electrode side (12) of the fuel cell (10) during the power generation operation. A fuel cell system comprising: a regeneration control means (102). 16. The oxygen opening / closing mechanism (8) according to claim 5 or 13, when the operation is stopped, the oxygen opening / closing mechanism (8) provided on the upstream side of the connecting portion of the mixer (81) in the oxygen passage (20).
8) and the hydrogen opening / closing mechanism (91) provided on the downstream side of the connection part of the mixer (81) in the hydrogen passage (21) are opened, and the mixer (81) is connected in the oxygen passage (20). Oxygen switching mechanism (89) provided on the downstream side of the section, a hydrogen switching mechanism (90) provided on the upstream side of the connection part of the mixer (81) in the hydrogen passage (21), and an oxygen bypass switching mechanism ( 8
A fuel cell system characterized by comprising stop control means (103) for closing the hydrogen bypass opening / closing mechanism (85). 17. The hydrogen opening / closing mechanism (9) according to claim 5 or 13, which is provided on a downstream side of a connecting portion of the mixer (81) in the hydrogen passage (21) when the operation is stopped.
1) and the oxygen opening / closing mechanism (88, 89) are opened, and the hydrogen opening / closing mechanism (90) provided on the upstream side of the connection part of the mixer (81) in the hydrogen passage (21) and the oxygen bypass opening / closing. A fuel cell system comprising a stop control means (103) for closing the mechanism (84) and the hydrogen bypass opening / closing mechanism (85). 18. The oxygen opening / closing mechanism (88) according to claim 6 or 14, which is provided upstream of the connecting portion of the connecting passage (93) in the oxygen passage (20) when the operation is stopped, and the hydrogen passage. The hydrogen opening / closing mechanism (91) and the connection opening / closing mechanism (94) provided on the downstream side of the connection portion of the connection passage (93) in (21) are opened, and the connection passage (93) in the oxygen passage (20) is opened. Oxygen opening / closing mechanism (89) provided on the downstream side of the connection portion of the hydrogen passageway (21) and hydrogen opening / closing mechanism (9) provided on the upstream side of the connection portion of the connection passageway (93) in the hydrogen passageway (21).
(0) and a stop control means (103) for closing the fuel cell system. 19. The hydrogen opening / closing mechanism (91) according to claim 6 or 14, which is provided downstream of a connecting portion of the connecting passage (93) in the hydrogen passage (21) when the operation is stopped, and an oxygen opening / closing mechanism. Mechanism (88, 89) and connection opening / closing mechanism (9
4) and a stop control means (103) for closing the hydrogen opening / closing mechanism (90) provided on the upstream side of the connection portion of the connection passage (93) in the hydrogen passage (21). Characteristic fuel cell system.