JP4603337B2 - Fuel cell system - Google Patents

Description

  The present invention relates to a fuel cell system that generates power by a reaction between a fuel gas and an oxidant gas.

  Conventionally, in a fuel cell system, a fuel gas (hydrogen) and an oxidant gas (air) containing hydrogen are respectively present at a fuel electrode (hydrogen electrode) and an oxidant electrode (air electrode) facing each other across a solid polymer film. Supplied. In order to reduce the fuel gas consumption in this fuel cell system and improve the output characteristics, the unused fuel gas discharged from the fuel electrode of the fuel cell is recirculated and newly supplied from the outside. A recirculation system that is mixed with fuel gas and supplied to the fuel electrode of a fuel cell is known (see, for example, Patent Document 1).

In this fuel cell system, when the exhaust gas from the fuel electrode is recirculated, the impurity concentration increases with repeated circulation, which decreases the electrode catalyst activity of the fuel cell and causes corrosion. The power generation performance of the fuel cell may be reduced.
For this reason, this fuel cell system is provided with a fuel electrode passage switching valve that switches between the fuel gas and the oxidant gas supplied to the fuel electrode passage according to the operating conditions, and the fuel electrode passage switching valve provides the fuel electrode passage with the fuel electrode passage switching valve. The oxidant gas is switched to supply, and the generated water accumulated in the fuel electrode is blown off by the oxidant gas to scavenge.
When such a scavenging system is introduced into such a fuel cell system, a fuel electrode passage switching valve for cutting off the fuel gas and the oxidant gas supplied to the fuel cell is required. The switching valve prevents the fuel gas and the oxidant gas from contacting each other than during scavenging.
Japanese Patent Laying-Open No. 2003-331893 (paragraphs 0012 to 0019, FIG. 1)

However, in the fuel cell system of Patent Document 1, when the fuel gas discharged from the fuel electrode is recirculated, the fuel gas flows from the fuel gas discharge port of the fuel electrode to the circulation passage, the ejector, the humidifier, and the fuel. It is sent to the fuel gas supply port of the fuel electrode through the pole passage switching valve and circulated. When impurities such as produced water accumulate in the fuel gas, the fuel electrode passage switching valve is switched to shut off the circulation of the fuel gas, introduce air from the compressor, and produce water and impurities in the circulation passage. The scavenging is performed by blowing off the fuel together with the fuel gas.
For this reason, of the fuel gas in the circulation passage, the fuel gas that was in the fuel gas discharge port of the fuel electrode from the fuel electrode passage switching valve is discharged to the outside, but the ejector, humidifier, and Since the fuel gas containing impurities existing between the fuel electrode passage switching valves is not affected by the air sent from the compressor, most of the fuel gas existing in the circulation passage remains without being pushed out.
Therefore, such a scavenging system has a problem in that the entire circulation passage is not scavenged, and impurities such as produced water in the fuel gas circulation system cannot be efficiently removed.

  Accordingly, the present invention has been made to solve the problems of the prior art, and an object of the present invention is to scavenge the entire area of the fuel gas circulation system and efficiently scavenge impurities such as generated water. It is to provide a battery system.

In order to solve the above-mentioned problem, a fuel cell system according to claim 1 is a fuel cell that generates power by a reaction between a fuel gas and an oxidant gas, and a fuel gas recirculated fuel gas sent to the fuel cell. A fuel gas circulation passage to be circulated by the apparatus, and a discharge of the fuel gas containing impurities in the fuel gas circulation passage disposed between the fuel gas discharge port of the fuel cell and the fuel gas recirculation device are adjusted. A discharge valve that discharges, a fuel gas discharge unit that discharges the fuel gas containing impurities that has passed through the discharge valve, an oxidant gas introduction path that can supply the oxidant gas to the fuel gas circulation passage, wherein the oxidizing agent gas flow path for sending the oxygen-containing gas to the fuel cell, the air as an oxidizing gas together fed into the oxidant gas flow path and the oxidant gas inlet passage, the oxidant in the normal power generation Graphics and compressor for supplying the introduction of the oxidant gas during scavenging, a fuel cell system wherein the fuel gas recirculation device consists ejector, the oxidant gas introduction path, the An oxidant gas introduction valve that is disposed between the discharge valve and the ejector and that controls the introduction of the oxidant gas to the fuel gas circulation passage is provided on the oxidant gas introduction path. The agent gas introduction valve is disposed in the diffuser portion of the ejector, and the ejector, the discharge valve, the fuel gas discharge portion, and the oxidant gas introduction valve are integrally coupled to the valve unit and disposed at close positions. It is characterized by being.

According to the invention of the fuel cell system according to claim 1, a discharge valve for discharging the fuel gas containing impurities in the fuel gas circulation passage, and a fuel gas recirculation device for circulating the fuel gas sent to the fuel cell Between them is an oxidant gas introduction path. When scavenging gas (oxidant gas) is flowed from this oxidant gas introduction path, all of the members that are provided in the fuel gas circulation passage and the fuel gas circulation passage and are likely to store generated water can be scavenged. All impurities including impurities such as produced water in the entire circulation system can be pushed out with oxidant gas and discharged. As a result, the generated water does not remain in the fuel circulation passage of the fuel cell system, and more complete scavenging can be performed, so that a failure at the time of restart can be prevented.
Furthermore, in the first aspect of the present invention, the exhaust valve and the oxidant gas introduction valve are arranged close to or integrally with each other, so that the wasteful scavenging range can be reduced and the scavenging volume can be reduced.
On the other hand, in the fuel gas circulation passage, the exhaust valve and the oxidant gas introduction valve are arranged close to or integrally with each other, so that substantially the entire circumference of the fuel gas circulation passage through which the fuel gas circulates can be scavenged. It is possible to scavenge.
Also, by integrating the discharge valve and the oxidant gas introduction valve, the piping between the discharge valve and the oxidant gas introduction valve is no longer required, reducing the number of parts and assembly steps, and improving assembly. Is done.

The fuel cell system according to claim 2 is the fuel cell system according to claim 1, wherein the discharge valve is provided between the oxidant gas introduction path and the discharge valve from the oxidant gas introduction path side. A check valve for preventing the backflow of gas to the side is provided.

According to the fuel cell system of the present invention, the check valve is disposed between the oxidant gas introduction path and the discharge valve, thereby scavenging oxidant gas in the oxidant gas introduction path. Is prevented from flowing directly from the oxidant gas introduction path toward the discharge valve. Thus, all of the oxidant gas introduced into the fuel gas circulation passage can be flowed to the fuel recirculation device side and used for scavenging. Accordingly, the entire area of the fuel cell and the fuel gas circulation system can be scavenged to efficiently scavenge impurities such as generated water.

The fuel cell system according to claim 3 is the fuel cell system according to claim 2 , wherein the check valve is integrally coupled to the valve unit .

According to the fuel cell system of the present invention, the number of components can be further reduced by integrally connecting the check valve to the valve unit.

According to the fuel cell system of the first aspect, the oxidant gas introduction path is disposed between the discharge valve and the fuel gas recirculation device, thereby scavenging the entire area of the fuel cell and the fuel gas circulation system. Thus, impurities such as produced water can be efficiently discharged.
Further, according to the fuel cell system according to claim 1, by the discharge valve and the oxidant gas inlet valve was disposed close to or integral, can scavenge substantially around the fuel gas circulation passage through which fuel gas is circulated Therefore, the generated water can be discharged evenly. In addition, since the piping between the discharge valve and the oxidant gas introduction valve becomes unnecessary, the number of parts and the number of assembly steps can be reduced, and the assemblability is improved.
According to the fuel cell system of claim 2 , since the check valve is disposed between the oxidant gas introduction path and the discharge valve, all of the oxidant gas introduced into the fuel gas circulation passage is removed. By flowing to the fuel recirculation device side, the entire area of the fuel gas circulation system is scavenged, and impurities such as produced water can be efficiently discharged.
According to the fuel cell system of the third aspect, the check valve is integrally coupled to the valve unit, so that the number of parts and the number of assembly steps can be further reduced, and the assemblability is improved.

Next, the best mode for carrying out the present invention (hereinafter referred to as “embodiment”) will be described with reference to FIGS.
FIG. 1 is a block diagram of a fuel cell system according to an embodiment of the present invention.

≪Fuel cell system≫
A fuel cell system 1 shown in FIG. 1 is used, for example, in a vehicle that travels with a fuel cell stack (hereinafter referred to as “fuel cell”) as a power source and a travel motor driven by the power of the fuel cell 2. The fuel cell system 1 includes a fuel cell 2 that generates power by a reaction between a supplied fuel gas and an oxidant gas, a fuel gas flow passage 3 through which the fuel gas flows, and an oxidant gas flow through which the oxidant gas flows. The oxidant gas introduction path 5 for introducing the oxidant gas into the fuel gas flow path 3 by communicating the path 4, the fuel gas flow path 3 and the oxidant gas flow path 4; An oxidant gas introduction valve 6 for blocking communication between the flow passage 3 and the oxidant gas flow passage 4 is provided.

≪Fuel cell≫
The fuel cell 2 shown in FIG. 1 is configured, for example, by stacking a plurality of fuel cells each sandwiching a solid polymer electrolyte membrane with a fuel electrode 2a and an oxidant electrode 2b interposed between separators. . The fuel cell 2 generates electric power by, for example, an electrochemical reaction between oxygen in the air as the oxidant gas supplied to the oxidant electrode 2b and hydrogen as the fuel gas supplied to the fuel electrode 2a. It is structured. When processing this hydrogen and oxygen, the fuel cell 2 generates electric power and heat.
The fuel electrode 2a is connected to the ejector 7 on the fuel gas supply port side to which one fuel gas (hydrogen) is supplied, and connected to the catch tank 8 on the other fuel gas discharge side. The oxidant electrode 2b has one oxidant gas supply port side connected to a compressor 14 constituting an air supply unit that supplies air as oxidant gas (oxygen), and the other oxidant gas discharge side connected to a back pressure valve 15. Has been.

≪Fuel gas flow path≫
The fuel gas flow passage 3 supplies a fuel gas made of hydrogen or the like from the fuel gas supply unit 10 to the fuel gas supply port of the fuel electrode 2a, and discharges the fuel gas in the fuel electrode 2a from the fuel gas discharge port to the outside. This is a flow passage for circulation. In the fuel gas passage 3, the fuel gas supply port side of the fuel electrode 2a, a fuel gas supply unit 10 and through the fuel gas introduction path 3a, (not shown) the pressure control unit, the ejector 7 is connected A catch tank 8, a check valve 11 and a discharge valve 13 are connected to the fuel gas discharge port side via a fuel gas circulation passage 3b. The fuel gas flow passage 3 includes a fuel gas introduction passage 3a, a fuel gas circulation passage 3b, and a discharge passage 3c, which will be described later.

<Fuel gas introduction path>
The fuel gas introduction path 3 a is a pipe for sending fuel gas from the fuel gas supply unit 10 to the fuel electrode 2 a via the ejector 7.

<Fuel gas circulation passage>
The fuel gas circulation passage 3b is configured to catch the exhaust fuel gas discharged from the fuel gas discharge port of the fuel cell 2 during the normal operation of the fuel cell system 1 as shown in FIG. This is a pipe for circulating through the ejector 7 to the fuel gas supply port of the fuel cell 2 again. One end of the fuel gas circulation passage 3b is connected to a joint portion a provided in the discharge passage 3c between the downstream portion of the catch tank 8 and the discharge valve 13, and the other end is an ejector for circulating the fuel gas. 7 and a joint portion b and a check valve 11 connected to an oxidant gas introduction passage 5 which will be described later. In addition, the joint parts a and b and the joint part c to be described later include, for example, a T-shaped joint.

<Discharge passage>
The discharge passage 3c is a pipe for discharging the fuel gas and the oxidant gas (scavenging gas) supplied to the fuel electrode 2a through the fuel gas introduction passage 3a to the outside through the discharge valve 13.

≪Fuel gas supply part≫
The fuel gas supply unit 10 includes a gas cylinder or the like, and stores the fuel gas supplied to the fuel electrode 2a of the fuel cell 2.

≪Ejecta≫
The ejector 7 is composed of a nozzle part and a diffuser part (not shown), and the fuel gas supplied from the fuel gas supply part 10 via the pressure control part (not shown) is accelerated when passing through the nozzle part. It is injected toward the diffuser part. When the fuel gas flows from the nozzle portion toward the diffuser portion at a high speed, a negative pressure is generated in the side flow chamber provided between the nozzle portion and the diffuser portion, and the fuel electrode passes through the fuel gas circulation passage 3b. The exhaust fuel gas on the 2a side is sucked and mixed with the fuel gas. The fuel gas and the exhaust fuel gas mixed in the ejector 7 are sent to the fuel gas supply port of the fuel cell 2. Further, the discharged fuel gas discharged from the fuel cell 2 circulates through the fuel gas circulation passage 3 b via the ejector 7 and is supplied to the fuel cell 2 again.
The ejector 7 corresponds to a “fuel gas recirculation device” recited in the claims.

≪Catch tank, drain valve≫
The catch tank 8 is a hollow box that separates excess water (mainly liquid water) in the fuel gas in the fuel gas flow passage 3 so that it can stay inside, and is a drain for discharging generated water. A valve 9 is installed.
The drain valve 9 is a valve capable of discharging the generated water staying in the catch tank 8 to the outside by opening the drain valve 9.

≪Check valve≫
The check valve 11 prevents the exhaust fuel gas and the scavenging gas flowing through the fuel gas circulation passage 3b from flowing in only one direction in the direction of arrow A in FIG. 1 (from the downstream side of the catch tank 8 toward the ejector 7). It is a valve to do. As shown in FIG. 1, the check valve 11 is interposed between the joint part a and the joint part b in the fuel gas circulation passage 3b.
In FIG. 1, the distance between the joint parts a and b and the distance between the joint part a and the check valve 11 are described as having a distance for convenience of creating a block diagram, but will be described later. The distance between them is actually short.

≪Fuel gas discharge part≫
The fuel gas discharge part 12 is a part for discharging the exhaust fuel gas and the scavenging gas discharged from the fuel gas discharge port of the fuel electrode 2a to the outside. The fuel gas discharge part 12 adjusts the discharge of the fuel gas. A discharge valve 13 is provided. The fuel gas discharge unit 12 is connected to the downstream side of the catch tank 8 in the fuel gas circulation passage 3b through a discharge valve 13.

≪Discharge valve≫
The discharge valve 13 is a valve whose opening / closing operation is controlled in accordance with the operating state of the fuel cell 2 and for discharging the fuel gas and scavenging gas (oxidant gas) containing impurities in the fuel gas circulation passage 3b to the outside. is there. The discharge valve 13 is disposed at least between the fuel gas discharge port of the fuel cell 2 and the ejector 7. In the present embodiment, the discharge valve 13 is disposed in the fuel gas flow passage 3 in a discharge passage 3 c provided outward from a joint portion a installed on the downstream side of the fuel cell 2.

≪Oxidant gas flow passage≫
The oxidant gas flow passage 4 supplies an oxidant gas such as air to the oxidant gas supply port of the oxidant electrode 2b, and discharges the oxidant gas in the oxidant electrode 2b from the oxidant gas discharge unit 16 to the outside. It is a flow passage for distribution. In the oxidant gas flow passage 4, a compressor 14, a heat radiating part and an oxidant humidification part are connected to the oxidant gas supply port side of the oxidant electrode 2b, and a back pressure valve 15 is connected to the oxidant gas discharge port side. Is connected. In the oxidant gas flow passage 4, an oxidant gas introduction path 5 described later is connected between the oxidant gas supply port of the fuel cell 2 and the compressor 14.

≪Compressor≫
The compressor 14 is a device for sending air as an oxidant gas into the oxidant gas flow path 4 and the oxidant gas introduction path 5, and is installed on the upstream side of the oxidant gas flow path 4.

≪Oxidant gas discharge part, back pressure valve≫
The oxidant gas discharge unit 16 is a part for discharging the oxidant gas discharged from the oxidant gas discharge port of the fuel cell 2 to the outside. The oxidant gas discharge unit 16 adjusts the discharge of the oxidant gas. A back pressure valve 15 is installed.

≪Oxidant gas introduction path≫
The oxidant gas introduction path 5 is a pipe for communicating the fuel gas flow path 3 and the oxidant gas flow path 4 to send the oxidant gas (scavenging gas) to the fuel gas circulation path 3b. The oxidant gas introduction path 5 is disposed at least between the discharge valve 13 and the ejector 7. In addition, in this embodiment, since it is the structure which has the non-return valve 11, one side of the oxidizing gas introduction path 5 is a joint arrange | positioned between the compressor 14 and the oxidizing gas supply port of the oxidizing agent electrode 2b. The other part is connected to the joint part b arranged between the ejector 7 and the check valve 11. On the oxidant gas introduction path 5, an oxidant gas introduction valve 6 for controlling the introduction of the oxidant gas to the fuel gas circulation path 3b is provided. Between the oxidant gas introduction path 5 and the discharge valve 13, the check valve 11 for preventing the backflow of the oxidant gas from the oxidant gas introduction path 5 side to the discharge valve 13 side is disposed. ing.
In addition, the said joint part b is installed in the position as close as possible to the joint part a installed in the discharge channel | path 3c.

≪Oxidant gas introduction valve≫
The oxidant gas introduction valve 6 shuts off the communication between the oxidant gas flow path 4 and the fuel gas flow path 3 during power generation of the fuel cell 2 and opens the valve body during scavenging to open the oxidant gas flow path 4. This is a valve for introducing an oxidant gas (scavenging gas) into the fuel gas flow passage 3. The oxidant gas introduction valve 6 has an outlet port side connected to the fuel gas flow passage 3 (high pressure side flow passage) side, and an introduction port side having an oxidant gas flow passage (low pressure side flow passage) whose pressure is lower than that of the fuel gas flow passage 3. ) It is connected to 4 side. The oxidant gas introduction valve 6 and the discharge valve 13 are arranged close to each other or integrally with each other.
The oxidant gas introduction valve 6 may be a check valve that flows only in one direction from the oxidant gas flow path 4 and the oxidant gas flow path 5 to the fuel gas flow path 3.

≪Valve unit≫
As shown in FIG. 1, the ejector 7, the joint portions a and b, the check valve 11, the oxidant gas introduction valve 6, the discharge valve 13, and the fuel gas discharge portion 12 are integrally coupled by a valve unit B, for example. Is provided.
By doing so, the valve unit B can omit the joint portions a and b. That is, the joint part a may be a flow path where the fuel gas circulation passage 3b and the discharge passage 3c merge and intersect. Moreover, the joint part b should just be a flow path where the fuel gas circulation path 3b and the oxidant gas introduction path 5 intersect.
Furthermore, the valve unit B shortens the distance between the joint part a and the joint part b and the distance between the discharge valve 13 and the oxidant gas introduction valve 6 so that these parts are close to each other. It can be installed.
Further, by integrally connecting the above-described parts, it is possible to eliminate the need for piping and joint portions a and b connecting the parts, and to make each part compact in a close position.

  FIG. 2 is a plan view showing an example of a valve unit used in the fuel cell system according to the embodiment of the present invention. FIG. 3 is a front view showing an example of a valve unit used in the fuel cell system according to the embodiment of the present invention.

Further, the valve unit B will be described with reference to FIGS.
As shown in FIGS. 2 and 3, the valve unit B is an apparatus in which the components of the fuel gas circulation system and the scavenging gas introduction system are integrated into one. In the valve unit B, for example, an ejector 7, a check valve 11, an oxidant gas introduction valve 6, a discharge valve 13, and a fuel gas discharge unit 12 are integrally coupled.

The ejector 7 takes in the fuel gas (arrow D) from the fuel gas supply unit 10 (see FIG. 1) installed outside the valve unit B and sends it to the fuel cell 2, and the exhausted fuel gas that has passed through the check valve 11. (Arrow E) and scavenging gas (arrow F) that has passed through the oxidant gas introduction valve 6 are sent to the fuel cell 2.
The check valve 11 is a valve that prevents the fuel gas and the scavenging gas from flowing back to the catch tank 8 side, and is integrally disposed at an adjacent position between the ejector 7, the oxidant gas introduction valve 6, and the discharge valve 13. Has been.
The oxidant gas introduction valve 6 communicates with the oxidant gas introduction path 5 (see FIG. 1) and is integrated with the check valve 11 so as to send the oxidant gas between the ejector 7 and the check valve 11. Is arranged.
The discharge valve 13 is a valve for appropriately discharging the discharged fuel gas (arrow G) flowing from the catch tank 8 side to the outside (arrow H) from the fuel gas discharge portion 12, and is integrated with the check valve 11. Is provided.

  Thereby, since the discharge valve 13 and the oxidant gas introduction valve 6 are integrally disposed, the distance between the discharge valve 13 and the oxidant gas introduction valve 6 can be narrowed and disposed at positions close to each other. Yes.

During normal operation of the fuel cell system 1, the exhaust fuel gas sent to the valve unit B through the fuel cell 2 and the catch tank 8 as shown by phantom arrows in FIGS. Circulation is performed so as to return to the fuel cell 2 again through the check valve 11 and the ejector 7.
During scavenging of the fuel cell system 1, the oxidant gas sent from the oxidant gas introduction path 5 (see FIG. 1) to the valve unit B is oxidant gas, as indicated by the dashed arrows in FIGS. The fuel is discharged from the fuel gas discharge unit 12 through the fuel cell 2, the catch tank 8 and the discharge valve 13 through the introduction valve 6 and the ejector 7.

  The oxidant gas introduction valve 6 is disposed in the diffuser portion of the ejector 7. The oxidant gas introduction valve 6 is installed at a position as close to the check valve 11 as possible on the upstream side of the fuel cell 2 on the downstream side immediately after the check valve 11 in the fuel gas circulation system.

<< Operation >>
Next, the operation of the fuel cell system 1 will be described with reference to the drawings.
As shown in FIG. 1, the fuel cell 2 is supplied from the fuel gas supply unit 10 through the ejector 7 through the fuel gas flow passage 3 and from the compressor 14 through the oxidant gas flow passage 4. Electric power and heat are generated by an electrochemical reaction with the oxidant gas (oxygen).

  During normal operation of the fuel cell system 1, the oxidant gas introduction valve 6 and the discharge valve 13 are closed by a control device (not shown). Therefore, the arrow indicates that the fuel gas sent from the ejector 7 to the fuel electrode 2a returns to the fuel electrode 2a again through the catch gas 8, the check valve 11, and the ejector 7 through the fuel gas circulation passage 3b. It is circulated in the A direction. In this way, fuel gas consumption is reduced.

  When the power generation state of the fuel cell 2 is stopped and the pressure of the fuel gas in the fuel gas circulation passage 3b decreases, the exhaust valve 13 and the oxidant gas introduction valve 6 are opened by a sensor and a control device (not shown). It is. Then, the fuel gas in the fuel gas circulation passage 3b is discharged from the discharge valve 13 to the outside through the discharge passage 3c and the discharge valve 13.

A check valve 11 prevents the oxidant gas from flowing from the oxidant gas introduction path 5 side to the discharge valve 13 side in the fuel gas circulation path 3 b between the oxidant gas introduction path 5 and the discharge valve 13. The oxidant gas (scavenging gas) is prevented from flowing from the oxidant gas introduction path 5 directly through the joint portion a toward the discharge valve 13 and being discharged.
As a result, the oxidant gas (scavenging gas) from the compressor 14 passes through the oxidant gas flow path 4, the oxidant gas introduction path 5, and the oxidant gas introduction valve 6, and the ejector 7 and the check valve 11. When flowing into the fuel gas circulation passage 3b, the fuel gas was discharged from the fuel gas discharge section 12 through the ejector 7, the fuel electrode 2a, the catch tank 8 and the discharge valve 13, and circulated through the fuel gas circulation passage 3b. The discharged fuel gas is scavenged as it is pushed out.

  At this time, the oxidant gas introduction path 5 provided with the oxidant gas introduction valve 6 is connected to the joint b provided in the fuel gas circulation passage 3b between the discharge valve 13 and the ejector (fuel gas recirculation device) 7. Further, the discharge valve 13 and the oxidant gas introduction valve 6 are disposed in close proximity to the valve unit B (see FIGS. 2 and 3). For this reason, the scavenging oxidant gas that has entered the fuel gas circulation passage 3b from the oxidant gas introduction passage 5 passes through the fuel cell 2 from the joint portion (merging point) b as shown in FIG. (Meeting point) By passing between a, the fuel gas circulation passage 3b is made to go around substantially once.

  Therefore, as for the oxidant gas, all of the oxidant gas introduced into the fuel gas circulation passage 3b is used for scavenging, and all impurities such as generated water in the entire region of the fuel gas circulation system are pushed out by the oxidant gas. The fuel gas is discharged from the fuel gas discharge unit 12 and can be scavenged evenly. As a result, the valve unit B can substantially reduce the portion of the fuel gas circulation passage 3b that is not scavenged, thereby reducing the wasteful scavenging range, and the moisture discharged from the fuel cell 2 into the fuel gas circulation passage 3b. It is possible to prevent the exhaust fuel gas containing the residual gas from remaining and make it difficult to cause a failure at the time of restart.

  In addition, the valve unit B integrates the oxidant gas introduction valve 6, the check valve 11, the ejector 7 and the discharge valve 13, thereby eliminating the need for piping between the valves, thereby reducing the scavenging volume. As a result, the number of parts and the number of assembly steps can be reduced, and assemblability is improved.

  When the scavenging of the discharged fuel gas is completed and when the fuel cell 2 is restored to the normal power generation state, the control device sends the fuel gas from the fuel gas supply unit 10 to the fuel electrode 2a via the ejector 7. The oxidant gas introduction valve 6 and the discharge valve 13 are shut off. Then, the fuel gas discharged from the fuel electrode 2 a is circulated again to return to the fuel electrode 2 a via the catch tank 8, the check valve 11, and the ejector 7.

  The present invention is not limited to the above-described embodiment, and various modifications and changes can be made within the scope of the technical idea. The present invention extends to these modifications and changes. Of course.

1 is a block diagram showing a fuel cell system according to an embodiment of the present invention. It is a top view which shows an example of the valve unit used for the fuel cell system which concerns on embodiment of this invention. It is a front view which shows an example of the valve unit used for the fuel cell system which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell system 2 Fuel cell 3 Fuel gas flow path 3b Fuel gas circulation path 4 Oxidant gas flow path 5 Oxidant gas introduction path 6 Oxidant gas introduction valve 7 Ejector (fuel gas recirculation device)
11 Check valve 13 Discharge valve B Valve unit

Claims (3)

A fuel cell that generates electricity by reaction between the fuel gas and the oxidant gas;
A fuel gas circulation passage for circulating the fuel gas sent to the fuel cell by a fuel gas recirculation device;
A discharge valve for adjusting the discharge of the fuel gas containing impurities of the fuel gas circulation passage disposed between the fuel cells in a fuel gas discharge port and the fuel gas recirculation device,
A fuel gas discharge part for discharging the fuel gas containing the impurities through the discharge valve to the outside;
An oxidant gas introduction path capable of supplying the oxidant gas to the fuel gas circulation path;
An oxidant gas flow path for sending the oxidant gas to the fuel cell;
A compressor that feeds air as the oxidant gas into the oxidant gas flow path and the oxidant gas introduction path, and supplies the oxidant gas during normal power generation and introduces the oxidant gas during scavenging; ,
A fuel cell system comprising:
The fuel gas recirculation device comprises an ejector,
The oxidant gas introduction path is disposed between the discharge valve and the ejector, and an oxidant that controls introduction of the oxidant gas into the fuel gas circulation path on the oxidant gas introduction path. A gas introduction valve is provided,
The oxidant gas introduction valve is disposed in a diffuser portion of the ejector,
The fuel cell system according to claim 1, wherein the ejector, the discharge valve, the fuel gas discharge unit, and the oxidant gas introduction valve are integrally coupled to a valve unit and arranged at close positions . The fuel cell system according to claim 1 ,
A fuel cell system, wherein a check valve for preventing a backflow of gas from the oxidant gas introduction path side to the discharge valve side is disposed between the oxidant gas introduction path and the discharge valve. . The fuel cell system according to claim 2 , wherein
The fuel cell system , wherein the check valve is integrally coupled to the valve unit .

Images