JP2003249253A - Fuel cell equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide fuel cell equipment in which a power supply that is made to drive an electric drive element is not necessary to be prepared and even when there is a number of cells, an increase in number of conductor wires or the like is prevented. <P>SOLUTION: The fuel cell equipment has a fuel cell 8 which is formed by connecting two or more cells 80 at least in series electrically, output terminals 100 outputting power generation voltage generated by the fuel cell 8, and output side switches 151, 152 by which the on-state, in which the fuel cell 8 and the output terminals 100 are electrically conducted, can be changed to the off-state, in which the fuel cell and the output terminals are not electrically conducted. The electric drive element 300 is electrically connected to the fuel cell 8 so that the power generation voltage of the fuel cell 8 can be impressed. And while the power generation voltage of the fuel cell 8 is impressed as input voltage of the minimum driver voltage or more of the electric drive element 300 to maintain output side switches 151, 152 in the on-state, when the power generation output of the fuel cell 8 decreases and the applied voltage to the electric drive element 300 falls lower than the minimum driver voltage of the electric drive element 300, the output side switches 151, 152 are changed to the off-state. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell device capable of detecting malfunction of cells.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No. 2000-67896 discloses
Fuel cell protection method and protection device in which an opto-isolator is assembled to a fuel cell formed by electrically connecting a plurality of cells each having a fuel electrode supplied with fuel and an oxidant electrode supplied with oxidant in series Is disclosed. The opto-isolator is for detecting malfunction detection means, and includes a light emitting diode provided in a circuit connecting two cells and a phototransistor which is turned on by receiving light emitted by each light emitting diode. A phototransistor array connected to each other and a comparator that outputs a high signal when any of all phototransistors are off are provided. The collector side of the phototransistor is electrically connected to a power source different from the fuel cell. According to this, when any of the cells forming the fuel cell malfunctions, all of the phototransistors are turned off, so the comparator outputs a high signal as a malfunction detection signal of the fuel cell. To do. This detects that one of the cells of the fuel cell is malfunctioning and issues an alarm.

Japanese Patent Laid-Open No. 7-272736 discloses that
A fuel provided with current limiting means for monitoring the generated voltage of each cell of the fuel cell by the voltage monitoring means and limiting the current supplied to the load when the generated voltage of the fuel cell is smaller than the minimum voltage threshold value. A controller for a battery system is disclosed. In this device, the voltage monitoring means is electrically connected to a power source different from the fuel cell.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
According to the technique of Japanese Patent Laid-Open No. 67896, the collector side of the phototransistor is electrically connected to a power source different from the fuel cell. Therefore, in order to detect the malfunction of the cell, another power source other than the fuel cell is required. Furthermore, since each cell of the fuel cell requires an opto-isolator that detects a malfunction, the number of opto-isolators increases, and the number of conductors connected to the opto-isolator increases, which causes a problem that noise is increased. Occurrence is likely to be induced, which may reduce reliability.

Further, according to the technique disclosed in Japanese Patent Laid-Open No. 7-272736, the voltage monitoring means functioning as the malfunction detecting means is electrically connected to a power source different from the fuel cell. Therefore, in order to detect the malfunction of the cell,
In addition to the fuel cell, another power source was needed. Further, since the generated voltage of each cell of the fuel cell is monitored by the voltage monitoring means, there is a problem that the number of monitoring means connected to each cell increases, which in turn increases the number of conducting wires connected to the monitoring means. Therefore, noise is likely to be generated, and reliability may be reduced.

The present invention has been made in view of the above-mentioned circumstances, and it is not necessary to provide a power source for driving the electric drive element, and moreover, even when the number of cells constituting the fuel cell is large, a conductor or the like is used. It is an object of the present invention to provide a fuel cell device which can prevent an increase in the number of fuel cells and can improve reliability.

[0007]

In a fuel cell device according to the present invention, a plurality of cells having a fuel electrode to which a fuel is supplied and an oxidant electrode to which an oxidant is supplied are electrically connected at least in series. And a fuel cell formed between the fuel cell and an output terminal for outputting a generated voltage generated by the fuel cell, and an ON state in which the fuel cell and the output terminal are electrically connected to each other. And an output side switch capable of electrically switching the output terminal to a non-conducting off state, the output side switch is turned on from an off state when an input voltage higher than the minimum drive voltage is applied. An electric drive element for switching to a state is provided, the electric drive element is electrically connected to the fuel cell so that the generated voltage of the fuel cell is applied, and the generated voltage of the fuel cell is the electric drive element. It is applied as an input voltage higher than the minimum drive voltage to maintain the output side switch in the ON state, and the power generation output of the fuel cell is reduced, and the voltage applied to the electric drive element is lower than the minimum drive voltage of the electric drive element. At this time, the output side switch is switched from the on state to the off state.

According to the fuel cell device of the present invention, when the generated voltage of the fuel cell is applied to the electric drive element as an input voltage higher than the minimum drive voltage of the electric drive element, the electric drive element turns off the output side switch. Switch from state to on state. On the other hand, when the power generation output of the fuel cell is reduced and the voltage applied to the electric drive element is lower than the minimum drive voltage of the electric drive element, the electric drive element switches the output side switch from the ON state to the OFF state. As a result, the extraction of the power generation output of the fuel cell from the output terminal is stopped.

According to the fuel cell device of the present invention, since the electric drive element is driven by the generated voltage of the fuel cell, no power supply is required to drive the electric drive element.

[0010]

According to a preferred state of the present invention, the electric drive element has a divided voltage obtained by dividing a generated voltage generated by a fuel cell by a resistor to be equal to or higher than a minimum drive voltage of the electric drive element, When the divided voltage obtained by driving the electric drive element with the divided voltage to maintain the output side switch in the ON state and the divided voltage obtained by dividing the generated voltage of the fuel cell by the resistance is lower than the minimum drive voltage of the electric drive element Can be switched from the on state to the off state. The minimum driving voltage means a voltage required to drive the electric driving element.

Due to the large number of cells connected in series so as to form a fuel cell, even when the generated voltage of the fuel cell greatly exceeds the minimum drive voltage of the electric drive element, power is generated by the fuel cell. If the divided voltage obtained by dividing the generated voltage is set to be equal to or higher than the lowest drive voltage of the electric drive element, the electric drive element can be driven and maintained in the ON state.

When the electric driving element is driven by the divided voltage obtained by dividing the generated voltage generated by the fuel cell in this way, each cell of the fuel cell is independent even when the total number of cells is large. It is possible to collectively detect the malfunctions of the above. In this case, a conductive path provided with a plurality of resistors for dividing the total generated voltage generated by the fuel cell into divided voltages is provided. The resistance may be a specific resistance having a fixed resistance value or a variable resistance capable of changing the resistance value.

According to a preferred aspect of the present invention, the electric drive element is driven by a control signal from the outside.
It can be configured by an electric drive element and a second electric drive element that is driven according to the driving of the first electric drive element to switch the output side switch from the off state to the on state.

According to a preferred aspect of the present invention, the first
The electric drive element and the second electric drive element may be a relay that turns on and off the output side switch. As the relay, a contact type electromagnetic relay or a non-contact type transistor can be adopted.

A fuel cell according to the present invention is a fuel cell formed by electrically connecting at least a plurality of cells each having a fuel electrode to which a fuel is supplied and an oxidant electrode to which an oxidant is supplied, in series. If it is good. As a typical fuel used in the fuel cell, a gaseous or liquid fuel can be adopted, and a hydrocarbon fuel or the like can be used. Specifically, a fluid containing at least one kind of methane, propane, butane, etc. as a main component can be used, and city gas, natural gas,
Methanol, gasoline, biogas, etc. can be illustrated. The fuel cell device may have a reforming unit that reforms the fuel so as to be suitable for power generation reaction, or may not have the reforming unit because the fuel is directly used inside the fuel cell. The fuel cell may be a commercial type, a domestic type, a stationary type, an on-vehicle type, a fixed type, a movable type, a portable type, or a portable type.

[0016]

(First Embodiment) A first embodiment of the present invention will be described below with reference to FIGS. In the fuel cell device according to this embodiment, a plurality of cells 80 having a fuel electrode to which a fuel (for example, a hydrogen-containing gas) is supplied and an oxidant electrode to which an oxidant (for example, air) is supplied are electrically connected in series. A fuel cell 8 formed by being connected to is provided.
Of the fuel cell 8, the cell 80a, the cell 80 from the negative electrode side
b, cell 80c ... Cell 80r ..., and cell 80y and cell 80z as it goes to the + pole side. Further, an output terminal 100 that outputs the generated voltage generated by the fuel cell 8 is provided. The output terminal 100 has a first output terminal 101 connected to the negative pole of the fuel cell 8 and a second output terminal 102 connected to the positive pole of the fuel cell 8. An output side switch 150 is provided between the fuel cell 8 and the output terminal 100. The output side switch 150 includes a first output side switch 151 which is provided between the first output terminal 101 and the negative electrode of the fuel cell 8 and which is normally open and in an off state.
It has a second output side switch 152 which is provided between the output terminal 102 and the + pole of the fuel cell 8 and which is normally opened and turned off.

When the first output side switch 151 and the second output side switch 152 are turned on, the fuel cell 8 and the output terminal 100 are electrically connected to each other, so that the power generation output of the fuel cell 8 is the output terminal 100. Is output from. On the other hand, the first output side switch 151 and the second output side switch 1
When at least one of 52 is opened and turned off, the fuel cell 8 and the output terminal 100 are electrically disconnected from each other, so that the power generation output of the fuel cell 8 is not output from the output terminal 100.

A protection controller 200 for switching the output side switch 150 is provided. The protection controller 200 includes a first electric drive element 230 that is turned on by a control signal PC from the outside. The first electric drive element 230 is formed of an electromagnetic relay,
It has a switch 250. When a voltage equal to or higher than the lowest driving voltage Vdri is applied to the first electric driving element 230, the first electric driving element 230 is driven so as to be excited. The minimum driving voltage Vdri of the first electric driving element 230 is the first
It means a voltage required to drive the electric driving element 230. The switch 250 is normally open and is in an off state. When a voltage equal to or higher than the lowest driving voltage Vdri is applied to the first electric driving element 230,
Since the electric driving element 230 is driven so as to be excited,
Switch 250 closes and switches from the off state to the on state.

Furthermore, a second electric drive element 300 is provided. The second electric drive element 300 is the first electric drive element 23.
With the excitation of 0, the state becomes excited and the output side switch 15
0 (151, 152) is switched from the off state to the on state. As shown in FIG. 2, the second electric drive element 300 is formed of an electromagnetic relay and is electrically connected in parallel with the first electric drive element 230. Second electric drive element 30
When a voltage equal to or higher than the minimum drive voltage Vdri is applied to 0, the second electric drive element 300 is driven so as to be excited, so that the first output side switch 151 and the second output side switch 152 are closed and turned on. It becomes a state. The minimum drive voltage Vdri of the second electric drive element 300 means the second electric drive element 3
Means the voltage required to drive 00. The minimum driving voltage Vdri of the second electric driving element 300 is
It corresponds to the minimum drive voltage Vdri of the electric drive element 230, and both are set to the same degree.

A photocoupler 400 as an input operation unit operated from the outside is provided in the protection controller 200. The photocoupler 400 functions as an isolated input element using photoelectric conversion, and has a control terminal 47.
A photodiode 410 that is electrically connected to 0 and emits light when a pulsed control signal PC is input to the control terminal 470, and a phototransistor 430 that receives light emitted by the photodiode 410 and is turned on. Have.
The phototransistor 430 is electrically connected in parallel to the contact-type switch 250, and is also connected in series to the first electric drive element 230 and the second electric drive element 300.

In other words, as shown in FIG. 2, the protection controller 200 includes a first electric drive element 230 having a contact type switch 250, and a photocoupler 400.
Have and. Conductor 201 of the protection controller 200,
202 is electrically connected to cells 80a to 80r, which are a part of all the cells 80 constituting the fuel cell 8, that is, an output terminal 201k for extracting a generated voltage between the cells 80a to 80r. , 202k.
The power generation voltage Va between the cells 80a to 80r is a part of the total power generation voltage of the fuel cell 8. Therefore, the number of the cells 80a to 80r is a predetermined number among all the cells 80 of the fuel cell 8, and the cell power generation voltage of the cells 80a to 80r, the first electric driving element 230, and the second electric driving element 30.
Although it varies depending on the minimum drive voltage Vdri of 0, for example, it can be basically about ½, ⅔, 3/4, etc. of all the cells 80 of the fuel cell 8.

When the operation of the fuel cell 8 reaches a steady state, the control signal PC is sent from the external control device to the control terminal 470.
Is input, the control signal PC is input to the photodiode 4
Input to 10. Then, the photodiode 410 emits light and the phototransistor 430 is turned on by photoelectric conversion, and the output terminal 201 of the generated voltage of the fuel cell 8 is taken out.
The k and 202k are electrically connected via the phototransistor 430. As a result, the voltage Va between the output terminals 201k and 202k is applied to the first electric drive element 230. Therefore, the voltage Va is the lowest drive voltage Vdr of the first electric drive element 230.
If i or more, the first electric drive element 230 is driven so as to be excited, the switch 250 is closed, and the switch 250
Switch from the off state to the on state. Then, a conductive path electrically connecting the second electric drive element 300 and the switch 250 is formed, and thus the voltage Va is applied to the second electric drive element 300. Since the voltage Va is equal to or higher than the lowest drive voltage Vdri of the second electric drive element 300,
The electric driving element 300 is excited and driven. By the way,
The first output side switch 151 and the second output side switch 152 of the output side switch 150 are closed and turned on. Therefore, the positive and negative electrodes of the fuel cell 8 and the output terminal 100 are electrically connected. Therefore, during the operation of the fuel cell 8, the power generation voltage between the positive electrode and the negative electrode of the fuel cell 8 can be taken out from the output terminal 100.

As described above, according to this embodiment, once the control signal PC is input to the photodiode 410, the voltage Va, which is a part of the power generation voltage of the fuel cell 8, is the lowest drive of the first electric drive element 230. If the voltage is equal to or higher than the voltage, the contact-type switch 250 is closed and maintained in the ON state. Therefore, the first output-side switch 151 and the second output-side of the output-side switch 150 are not input even if the control signal PC is not input thereafter. Switch 152 remains closed. That is, a self-holding circuit is formed.

According to this embodiment, the cell voltage Vcell is the power generation voltage generated by one cell 80 when the fuel cell 8 is in steady operation. When it is determined that it is not preferable to perform the steady operation of the fuel cell 8, the power generation voltage generated by one cell 80 is set as the minimum cell operable voltage Vmin. When the power generation voltage generated by one cell 80 is lower than the cell operable minimum voltage Vmin, it is preferable to stop the fuel cell 8 without operating it. Further, the number of cells between the cells 80a to 80r forming the voltage Va applied to the first electric drive element 230 and the second electric drive element 300 is N.

The minimum driving voltage Vdri of the first electric driving element 230 and the second electric driving element 300 is related to the minimum cell operating voltage Vmin and the number N of cells. That is, according to the present embodiment, the minimum driving voltage Vmin of the first electric driving element 230 and the minimum driving voltage Vdri of the second electric driving element 300 are calculated as follows:
The first electric drive element 230 and the second electric drive element 300 are set so as to have a value exceeding the minimum drive voltage Vdri corresponding to
Is selected.

Therefore, according to this embodiment, since the power generation amount of the fuel cell 8 is lowered during the operation of the fuel cell 8, the voltage value of (cell operable minimum voltage Vmin) × (cell number N) is the minimum drive voltage Vdri. When lower than the above, both the first electric drive element 230 and the second electric drive element 300 are automatically demagnetized and switched to the off state.

Even when the fuel cell 8 is operating, the fuel cell 8
Due to insufficient supply of fuel and oxidizer, insufficient humidification inside the fuel cell 8, excessive humidification, etc.
The generated voltage between the positive and negative poles of may decrease. In this case, if the operation of taking out the generated voltage of the fuel cell 8 from the output terminal 100 is continued as it is, the fuel cell 8 is easily damaged, which is not preferable for extending the life of the fuel cell 8. When the overall power generation output of the fuel cell 8 decreases, the voltage Va between the output terminals 201k and 202k of the fuel cell 8 also decreases.

When the voltage Va related to the generated voltage of the fuel cell 8 becomes lower than the minimum driving voltage Vdri of the first electric driving element 230, the first electric driving element 230 is automatically driven so as to be demagnetized. 1 switch 2 of electric drive element 230
50 is automatically switched from closed (on state) to open (off state). As a result, the conductive path connecting the second electric drive element 300 and the switch 250 is not formed, the second electric drive element 300 is driven so as to be demagnetized, and the first output side switch 151 and the second output side switch 152 are It is opened and turned off. As a result, the positive electrode and the negative electrode of the fuel cell 8
It is possible to prevent the generated voltage between the electrodes from being taken out from the output terminal 100. Therefore, damage to the fuel cell 8 is prevented, and the life of the fuel cell 8 can be extended. In the present embodiment, as shown in FIG. 1, the fuel cell 8, the output terminal 100, the output side switch 150, the protection controller 200, the second electric drive element 300, and the control terminal 470 are integrated modules. It is set to 600.

According to this embodiment, cells 80a to 80
The generated voltage between r and the voltage Va is the first electric drive element 230,
Since they are driven by being applied to the second electric drive element 300, it is possible to suppress an increase in the number of conductive wires even when the number of cells 80a to 80r of the fuel cell 8 is large, and it is possible to suppress noise. And so on can improve reliability.

Although the output side switch 150 has the first output side switch 151 and the second output side switch 152, either one may be used depending on the case.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to FIGS. 3 and 4. The second embodiment has basically the same configuration as the first embodiment, and basically has the same operational effect. Hereinafter, the different parts will be mainly described. According to this embodiment, the conductive path 105 that connects between the positive electrode and the negative electrode of the fuel cell 8 is provided electrically in parallel to the output terminal 100. And conductive path 1
A plurality of resistors is connected to 05 in series. Specifically, as shown in FIG. 3, in the conductive path 105, a first resistor 106 (resistance value: R1) and a second resistor 107 (resistance value: R2) are connected in series from the negative electrode side of the fuel cell 8. Has been done. Lead-out terminal 20 on the + pole side of the controller 200 for protection
1k is electrically connected between the first resistor 106 and the second resistor 107. The minus terminal 202k of the protection controller 200 is electrically connected to the minus electrode of the fuel cell 8.

When the fuel cell 8 generates power, the power generation voltage of the fuel cell 8 is taken out from the output terminal 100, as described in the first embodiment. At this time, the current I flows through the conductive path 105. The divided voltage Vc is generated in the conductive path 105 by the first resistor 106. The divided voltage Vc is basically obtained by the current I × {R1 / (R1 + R2)}. This divided voltage Vc is the lowest drive voltage V of the first electric drive element 230.
When the divided voltage Vc is equal to or higher than dri and the divided voltage Vc is applied to the first electric drive element 230, the first electric drive element 230 is driven so as to be excited, and the switch 250 is closed and turned on.

Also in this embodiment, as in the first embodiment,
When the operation of the fuel cell 8 reaches a steady state, the control signal P
C is input to the photodiode 410 via the control terminal 470. Then, the photodiode 410 emits light, and the phototransistor 430 is turned on by photoelectric conversion.
A divided voltage Vc obtained by dividing the power generation voltage of the fuel cell 8 is generated in the conductive path 105 by the first resistor 106. The divided voltage Vc is the lowest drive voltage Vdr of the first electric drive element 230.
When it is equal to or more than i, the first electric drive element 230 is driven to be excited by the divided voltage Vc, and the switch 250 is closed and turned on.

Then, as in the case of the first embodiment, a conductive path connecting the second electric drive element 300 and the switch 250 is formed. Therefore, the divided voltage Vc is also applied to the second electric drive element 300, so that the second electric drive element 300 is
Are driven so as to be excited, and by extension, the first output side switch 151 and the second output side switch 152 are closed to be in the ON state. Therefore, during the power generation of the fuel cell 8, the power generation voltage between the positive electrode and the negative electrode of the fuel cell 8 can be taken out from the output terminal 100.

On the other hand, due to lack of fuel and oxidant supplied to the fuel cell 8, insufficient humidification inside the fuel cell 8 and excessive humidification, the generated voltage between the positive and negative electrodes of the fuel cell 8 is increased. May decrease. When the power generation output of the fuel cell 8 decreases in this way, the first resistance 106 of the conductive path 105 is reduced.
The division voltage Vc of the fuel cell 8 generated at 1 also decreases.

When the divided voltage Vc becomes lower than the minimum driving voltage Vdri of the first electric driving element 230, the first electric driving element 230 is driven so as to be demagnetized, and the switch 250 is closed (on state) to open (off). State).
As a result, the second electric driving element 300 and the switch 250
A conductive path connecting the two is not formed, and the second electric drive element 300
Drive so as to demagnetize the first output side switch 151
Also, the second output side switch 152 is opened and turned off. As a result, it is possible to prevent the generated voltage between the positive electrode and the negative electrode of the fuel cell 8 from being taken out from the output terminal 100, prevent the fuel cell 8 from being damaged, and prolong the life of the fuel cell 8.

According to the present embodiment, the division voltage Vc obtained by dividing the generated voltage generated by all the cells 80 of the fuel cell 8 is used, and the first electric drive element 230 is excited by the division voltage Vc to drive the first electric drive element 230. Has been adopted. Therefore, when any one of all cells 80 of the fuel cell 8 is malfunctioning, it is automatically prevented that the generated voltage of the fuel cell 8 is taken out from the output terminal 100, and the fuel cell 8 is not needed. The load is suppressed, the fuel cell 8 is prevented from being damaged, and the life of the fuel cell 8 can be extended.

According to this embodiment, the resistance value of the first resistor 106 is R1, and the resistance value of the second resistor 107 is R2.
As described above, the divided voltage Vc is basically the current I × {R
This corresponds to 1 / (R1 + R2)}. In this embodiment, the divided voltage Vc defined by the resistance value R1 of the first resistor 106 and the resistance value R2 of the second resistor 107 is the lowest drive voltage Vdri of the first electric drive element 230 and the second electric drive element 300.
Of the first resistor 106 so as to exceed the minimum drive voltage Vdri of
And the resistance value R2 of the second resistor 107 are set.

According to this embodiment, the cell 80 of the fuel cell 8 is
Of all, that is, the generated voltage between the cells 80a to 80z is divided by a predetermined ratio {R1 / (R1 + R2)}, the divided voltage Vc is used. Therefore, even if the number of cells 80a to 80z is large, Can be suppressed and the reliability against noise and the like can be improved. One or both of the first resistor 106 and the second resistor 107 is
It may be a fixed resistor or a variable resistor whose resistance value can be changed. The output-side switch 150 has the first output-side switch 151 and the second output-side switch 152, but either one may be used.

(Application Example) An application example of the present invention will be described below. FIG. 5 shows a conceptual diagram of a stationary fuel cell device. As shown in FIG. 5, the fuel cell device according to the present example is provided with a reforming system 1M that generates a hydrogen-containing gas suitable for power generation by causing a reforming reaction between a fuel gas containing hydrogen as a fuel and steam. Has been. The reforming system 1M includes a reforming unit 1 that reacts a fuel gas and steam to generate a reforming reaction to generate a hydrogen-containing gas suitable for power generation, and evaporates raw material water to generate steam used in the reforming reaction. Evaporator 2 and reformer 1 that generate
1 for heating the fuel to a temperature range suitable for the reforming reaction
3 has a CO removal unit 5. The heat of the combustion section 13 is the heat of the reforming section 1
Therefore, the reforming section 1 is heated to a high temperature suitable for the reforming reaction. The CO removing unit 5 removes carbon monoxide contained in the hydrogen-containing gas generated in the reforming unit 1. The CO removal unit 5 has a CO shift unit that reduces carbon monoxide by a shift reaction and a CO selective oxidation unit that reduces carbon monoxide by using air, but the CO removal unit 5 is not limited to these.

A fuel gas supply passage (fuel supply passage) 4 for supplying fuel gas to the reforming portion 1 via the heat exchange portion 3 is provided. A fuel gas source 15 is provided at the upstream end of the fuel gas supply passage 4.
It is connected to (city gas piping) and supplies fuel gas containing at least one of methane, propane, butane, etc. as a main component. The fuel gas supply passage 4 is provided with a dual valve 29 including two valves 27 and 28 arranged in parallel, a fuel gas transfer pump 4p, a desulfurization section 4a, a valve 4b, and a confluence section 4c. The merging unit 4 c merges and mixes the fuel gas from the fuel gas supply passage 4 and the water vapor evaporated in the evaporation unit 2, and supplies the fuel gas to the reforming unit 1 via the heat exchange unit 3.

A combustion part communication passage 14 for supplying combustion fuel gas to the combustion part 13 is provided. Combustion section communication passage 14
Connects the fuel gas supply passage 4 and the combustion portion 13 via the branch portion 4m. The combustion section communication passage 14 is provided with a pump 14p as a gas carrier source for carrying the combustion fuel gas toward the combustion section 13. The fuel gas supplied from the fuel gas supply passage 4 is supplied to the combustion portion 13 through the combustion portion communication passage 14 by the pump 14p and used for the combustion reaction in the combustion portion 13, so that the combustion portion 13 has a high temperature. Since the reforming section 10 is heated by the combustion section 13, the reforming section 1
The temperature can be maintained in the temperature range suitable for the reforming reaction, and the hydrogen-containing gas can be effectively generated by the reforming reaction in the reforming section 1.

As shown in FIG. 5, a fuel cell 8 is provided. The fuel cell 8 generates electricity by using air (oxidant gas) as an oxygen-containing gas and hydrogen-containing gas. The fuel cell 8 is a polymer electrolyte type and is composed of a stack in which a plurality of cells using a proton conductive polymer membrane as an electrolyte are laminated in series. Each cell is electrically connected at least in series. A hydrogen supply passage 9 (fuel supply passage) for supplying the hydrogen-containing gas generated in the reforming section 1 to the fuel electrode of the fuel cell 8 via the valve 9a is provided.

As shown in FIG. 5, an air supply passage 16 (oxidant supply passage) for supplying air as an oxygen-containing gas as an oxidant for power generation to the air electrode of the fuel cell 8 is provided. The air supply passage 16 is provided with an air purifying filter 16a, an air carrying fan 16b, and an air humidifying unit 20. The humidifying unit 20 humidifies the air that is the oxygen-containing gas supplied to the fuel cell 8. When the electrolyte membrane of the fuel cell 8 is excessively dried, the power generation efficiency of the fuel cell 8 is reduced, so the air supplied to the air electrode of the fuel cell 8 is humidified.

A fuel off-gas passage 12 is provided for flowing the off-gas of the hydrogen-containing gas after power generation discharged from the outlet 8e of the fuel electrode of the fuel cell 8 to the combustion section 13. A valve 10a is provided in the fuel off-gas passage 12, a condensing section 10 on the fuel electrode side, a valve 1
0c is provided. The fuel electrode side condensing portion 10 is provided so as to be located between the combustion portion 13 and the fuel cell 8 in the fuel off-gas passage 12, and the hydrogen-containing gas discharged from the fuel electrode outlet 8e of the fuel cell 8 is discharged. The water contained in the offgas after the power generation is removed. The off gas from which the water has been removed is supplied to the combustion section 13 through the fuel off gas passage 12 and used as a combustion reaction. The off gas from which the moisture has been removed is supplied to the combustion section 13 and used as a combustion reaction, so that the off gas of the hydrogen-containing gas can be reused. At this time, the water contained in the off gas of the hydrogen-containing gas has been removed, so that the combustion unit 1
The temperature decrease of 3 is suppressed, and the combustion reaction in the combustion section 13 can be favorably performed.

An air off-gas passage (oxidant off-gas passage) 18 is provided for causing an off-gas of the air after power generation discharged from the air electrode of the fuel cell 8 to flow into the atmosphere. A humidifying section 20 is provided in the air off-gas passage 18.

A raw water supply passage 7 is provided which connects a water pipe as a water supply source and the evaporator 2. The water supplied from the raw material water supply passage 7 to the evaporator 2 is heated in the evaporator 2 to become steam, which is used for the reforming reaction in the reformer 1. In the raw material water supply passage 7, a filter 7a for purifying raw material water, a valve 7b, a valve 7c, a water purifying device 7d for enhancing the degree of purification of raw material water, a water tank 6, and a pump 7 for conveying raw material water.
An open / close control valve 7h is provided.

Further, as shown in FIG. 5, a cooling passage 22 for the cell through which cooling water that removes heat from the fuel cell 8 flows is provided. A pump 22p and a heat exchange unit 23 are provided in the battery cooling passage 22. A hot water storage unit 26 that removes heat generated in the entire fuel cell device and stores it as hot water is provided together with a hot water temperature sensor 26n. Discharge port 26 of hot water storage unit 26
The heat exchange passage 31 extending from i is provided with a pump 31p for transporting cooling water and a condenser section 10 on the fuel side,
Further, a plurality of heat exchange parts (not shown) are provided at appropriate portions. Therefore, the cooling water flowing from the hot water storage section 26 through the heat exchange passage 31 flows through the condenser section 10 on the fuel side and further through a plurality of heat exchange sections (not shown) provided at appropriate portions, and is heated by heat exchange to generate heat. It returns to the suction port 26o of the hot water storage unit 26 via the exchange unit 23. Therefore, the cooling water stored in the hot water storage unit 26 becomes hot and becomes hot water. The hot water that is the cooling water for the hot water storage unit 26 can be used as a hot water supply source for other purposes. Hot water storage section 26
Is supplied with water from a water supply source via a supply passage 26k. Various signals (S1, S2
Etc.) is input.

Since the technique according to the first or second embodiment described above is also applied to this application example, the fuel and oxidant supplied to the fuel cell 8 are insufficient, and the fuel cell 8
Even if the power generation voltage of the fuel cell 8 should drop due to insufficient humidification or excessive humidification inside the fuel cell, if the power generation voltage of the fuel cell 8 drops below a certain level, the power generation voltage of the fuel cell 8 drops. Is prevented from being taken out from the output terminal 100, so that the fuel cell 8 is prevented from being damaged and the fuel cell 8
Can have a long life.

In addition, the present invention is not limited to the above-mentioned embodiments, but can be carried out by appropriately changing it without departing from the scope of the invention.

[0051]

As described above, according to the fuel cell device of the present invention, when the generated voltage of the fuel cell is applied to the electric drive element as an input voltage higher than the minimum drive voltage of the electric drive element, the electric drive The element is driven to switch the output side switch from the off state to the on state. On the other hand, when the power generation output of the fuel cell is reduced and the voltage applied to the electric drive element is lower than the minimum drive voltage of the electric drive element, the electric drive element automatically switches the output side switch from the ON state to the OFF state. . This can prevent an unnecessary load from being applied to the fuel cell, which is advantageous for preventing damage to the fuel cell and, in turn, for prolonging the life of the fuel cell.

In the fuel cell device according to the present invention as described above, since the electric drive element is driven by the generated voltage of the fuel cell being applied, a power supply for driving the electric drive element is not required.

According to the fuel cell device of the present invention, even when the number of cells constituting the fuel cell is large,
It is possible to suppress an increase in the number of conducting wires, and there is an advantage that reliability with respect to noise and the like can be improved.

[Brief description of drawings]

FIG. 1 is a circuit diagram illustrating a circuit near a fuel cell according to a first embodiment.

FIG. 2 is a circuit diagram showing a circuit of a protection controller according to the first embodiment.

FIG. 3 is a circuit diagram showing a circuit near a fuel cell according to the second embodiment.

FIG. 4 is a circuit diagram showing a circuit of a protection controller according to the second embodiment.

FIG. 5 is a conceptual diagram of a fixed topography fuel cell device.

[Explanation of symbols]

In the figure, 8 is a fuel cell, 80 is a cell, 100 is an output terminal,
106 and 107 are resistors for dividing voltage, 150 is an output side switch, 200 is a protection controller, 230 is a first electric drive element, 250 is a switch, 300 is a second electric drive element, and 400 is a photocoupler.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shogo Goto             1 Toyota Town, Toyota City, Aichi Prefecture Toyota Auto             Car Co., Ltd. F-term (reference) 5H027 AA02 BA01 KK54

Claims (3)

[Claims] 1. A fuel cell formed by electrically connecting at least a plurality of cells having a fuel electrode to which a fuel is supplied and an oxidant electrode to which an oxidant is supplied in series, and power generation by the fuel cell. An output terminal that outputs a generated voltage, an ON state that is provided between the fuel cell and the output terminal and electrically connects the fuel cell and the output terminal, and the fuel cell and the output terminal are electrically connected. In a fuel cell device having an output side switch that can be switched to an off state that is electrically non-conducting, an electric switch that switches the output side switch from an off state to an on state when an input voltage equal to or higher than a minimum drive voltage is applied. A drive element is provided, the electric drive element is electrically connected to the fuel cell so that the generated voltage of the fuel cell is applied, and the generated voltage of the fuel cell is The output voltage is applied as an input voltage equal to or higher than the lowest drive voltage of the electric drive element to maintain the output side switch in the ON state, and the power generation voltage of the fuel cell is reduced to reduce the voltage applied to the electric drive element to the electric drive. A fuel cell device, wherein the output side switch is switched from an on state to an off state when the voltage is lower than the minimum drive voltage of the element. 2. The electric drive element according to claim 1,
While maintaining the output side switch in the ON state by driving the generated voltage generated by the fuel cell by dividing it with a resistor and driving the divided voltage with the minimum driving voltage or higher.
A fuel cell device, wherein the output side switch is switched from an on state to an off state when a divided voltage obtained by dividing a generated voltage of the fuel cell by a resistor is lower than a minimum driving voltage of the electric drive element. 3. The electric drive element according to claim 1,
A first electric drive element driven by a control signal from the outside, and a second electric drive element driven by the drive of the first electric drive element to switch the output side switch from an off state to an on state. A fuel cell device characterized by being provided.