JPH07235324A - Drive device of fuel cell - Google Patents

Abstract

PURPOSE:To generate continuous electromotive force effectively by performing the removal of the produced water from near the electrode with good responsiveness. CONSTITUTION:The CPU 62 of an electronic control unit 60 senses excessive leak at the surface of the cathode of a solid highpolymer type fuel cell 10 from the output voltage E sensed by a voltmeter 52 and the impedance Z sensed by an impedance meter 54, and performs accordingly the control to enlarge the degree of opening of a motor-driven valve 34 provided in a bypass piping 30. Associated with the rate of flow in the bypass piping 30 is increased, and the rate of flow of the oxygen gas supplied to the cathode of the fuel cell 10 is increased. When the rate of flow of the oxygen gas is increased to V1, water drops coagulated at and attached to the surface of the cathode 120 of the fuel cell 10 are blown off by the dynamic pressure of the oxygen gas of the rate of flow V1 and passed through a gas exhaust piping 40 to be exhausted to the outside. Thereby thin holes at the surface of the cathode can be prevented from being choked with the water drops.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving device for a fuel cell, which supplies gas to electrodes to obtain electromotive force from a chemical reaction of the supplied gas.

[0002]

2. Description of the Related Art For example, in a polymer electrolyte fuel cell, which is one of the fuel cells, a reaction of converting hydrogen gas into hydrogen ions and electrons at the anode and oxygen gas and hydrogen ions at the cathode are performed as shown in the following equation. And the reaction of producing water from the electrons takes place. Anode: H ₂ → 2H ⁺ + 2e ⁻ Cathode: 2H ⁺ + 2e ⁻ + (1/2) O ₂ → H ₂ O

In order to carry out these reactions continuously,
It is necessary to continuously supply the reactant to the electrode and remove the product from the vicinity of the electrode. In the case of the polymer electrolyte fuel cell, it is necessary to continuously supply oxygen and remove water as a product at the cathode. This is because if the product water is not removed, the water will stay near the electrodes and block the pores of the electrode base material, reducing the operating efficiency and possibly stopping the reaction.

Conventionally, a hydrophobic portion and a hydrophilic portion are alternately provided on an electrode as a driving device of a fuel cell for efficiently and continuously converting energy by eliminating generated water near the electrode. It has been proposed that the water absorbed in the hydrophilic part be discharged to the outside of the fuel cell with a wick made of cotton fibers (JP-A-4-1246).
No. 2). Further, as a device having the same effect, a porous water-resistant carbon paper is provided between the electrolyte membrane and the cathode-side gas flow path, and water generated on the surface of the porous water-resistant carbon paper is removed from the fuel cell by gas pressure. It has also been proposed to discharge it to (Japanese Patent Laid-Open No. 2-86071).

[0005]

However, in these devices, the water starts to be drained only after the water has sufficiently penetrated into the water-resistant carbon paper or the wick, so that even if the water is suddenly excessive, the water is immediately discharged. Could not drain water. As a result, the output of the fuel cell is reduced, and the operating efficiency is temporarily reduced. Further, these water-resistant carbon papers and wicks have low heat resistance, which causes a problem of deteriorating the durability of the fuel cell.

The fuel cell drive apparatus of the present invention has been made in view of these problems, and an object thereof is to efficiently and continuously obtain an electromotive force by efficiently removing generated water near the electrodes. I am trying.

[0007]

In order to achieve such an object, the following constitution is adopted as a means for solving the above problems.

That is, the first fuel cell driving apparatus of the present invention is a fuel cell driving apparatus that supplies gas to an electrode to obtain electromotive force from a chemical reaction of the supplied gas. And a dynamic pressure for temporarily increasing the dynamic pressure of the supply gas supplied to the electrode when the electrode wet state detecting means detects an excessively wet state of the electrode. The gist is that it is equipped with an increasing means.

In the drive device for the first fuel cell,
The dynamic pressure increasing means may be configured to have a circulation means for circulating the exhausted amount of the supply gas from the fuel cell to the fuel cell, and a circulation amount adjusting means for changing the circulation amount of gas by the circulation means. Good.

The dynamic pressure increasing means is provided in a gas supply passage for supplying the supply gas to the fuel cell or a gas discharge passage for discharging the supply gas from the fuel cell, and controls the gas pressure in the gas passage. It may be configured to have a gas pressure adjusting means for adjusting.

Further, in the first fuel cell drive device, a gas supply path for supplying a supply gas to the fuel cell and a humidifier provided in the gas supply path for humidifying the supply gas are provided. At the same time, the dynamic pressure increasing means has a bypass path that bypasses the gas supply path and supplies a dry supply gas to the fuel cell, and a bypass flow rate control means that controls the flow rate of the bypass path. Good.

On the other hand, the second fuel cell driving apparatus of the present invention is a fuel provided with a plurality of cell units each of which is an assembly of single cells for supplying gas to the electrodes and obtaining electromotive force from the chemical reaction of the supplied gas. A battery driving device, wherein an electrode wet state detecting means for detecting a wet state of the electrode, and when the electrode wet state detecting means detects an excessively wet state of the electrode in any of the battery units, The gist of the present invention is to include a dynamic pressure increasing means for temporarily increasing the dynamic pressure of the supply gas supplied to the electrodes of the battery unit.

In the drive device for the first fuel cell,
The dynamic pressure increasing means is a means for increasing the dynamic pressure of the supply gas over a plurality of battery units including at least a battery unit having the electrode that is too wet,
The configuration may be as follows.

When there are a plurality of battery units that increase the dynamic pressure of the supply gas, the dynamic pressure increasing means executes the increase timing of the dynamic pressure of the supply gas with a time lag for each battery unit. It may be configured to have a determining unit.

Further, the dynamic pressure increasing means is provided in the discharge passage of each battery unit for discharging the supply gas, and the gas pressure adjusting means for adjusting the gas pressure in the discharge passage and the electrode wet state. When a state in which the electrode is too wet is detected in any of the battery units by the detection means,
By temporarily increasing the dynamic pressure of the supply gas supplied to the electrode of the battery unit by adjusting the gas pressure adjusting means corresponding to the battery unit, among other battery units other than the battery unit It may be configured to include a control unit that temporarily reduces the dynamic pressure of the supply gas supplied to the electrodes of the battery units by adjusting the gas pressure adjustment unit corresponding to at least one.

In the first or second fuel cell driving device, the electrode is preferably a cathode.
Furthermore, the electrodes may be anodes and may be both cathodes and anodes.

In the first or second fuel cell drive device, the fuel cell includes a groove portion that is in contact with the surface of the electrode and supplies gas to the electrode, and the inner surface of the groove portion is water-repellent treated. It may be configured as a thing.

[0018]

According to the fuel cell driving apparatus of the first aspect,
When the electrode wetting state detecting means detects that the electrode of the fuel cell is too wet, the dynamic pressure of the supply gas supplied to the electrode is temporarily increased by the supply gas dynamic pressure increasing means. Therefore, the surplus water generated near the electrodes by the operation of the fuel cell is quickly blown off by the increased dynamic pressure and is discharged to the outside of the fuel cell through the flow path of the supply gas. Therefore, the pores of the electrode base material are responsively prevented from being blocked by the excess water.

According to the fuel cell driving device of the second aspect, the supply gas can be supplied to the fuel cell by the amount of the supply gas discharged from the fuel cell by the circulation means, so that the supply gas can be saved. Is planned.

According to the third aspect of the present invention, there is provided the fuel cell driving device, wherein the gas pressure adjusting means is provided in the gas supply path for supplying the supply gas to the fuel cell or the gas discharge path for discharging the supply gas from the fuel cell. It is only necessary to provide it, and the configuration is simple.

According to the fourth aspect of the present invention, the fuel cell driving apparatus supplies the fuel cell with the supply gas humidified by the humidifier through the gas supply passage and the dry supply gas through the bypass passage. Supplied. Then, the amount of dried gas can be increased by controlling the bypass flow rate control means. As a result, since the increased amount of the supply gas is dry in combination with the effect of the above-described blowout by the increased dynamic pressure of the supply gas, the surplus water generated near the electrodes is more responsively removed.

According to the fifth aspect of the fuel cell driving apparatus, when the electrode wetting state detecting means detects that the electrode is too wet in any one of the battery units which are the assembly of the unit cells, The dynamic pressure of the supply gas supplied to the electrode of the battery unit is temporarily increased by the supply gas dynamic pressure increasing means. Therefore, even when a plurality of battery units are provided, excess water generated in the vicinity of the electrode that has become too wet is quickly blown off by the increased dynamic pressure of the supply gas, and the pores of the electrode base material are Responsively prevent being blocked by excess water.

According to the fuel cell driving apparatus of the sixth aspect, the target of increase in the dynamic pressure of the supply gas is a plurality of battery units including at least a battery unit having an electrode that is too wet. Since it is not necessary to specify the electrode that is too wet, the control configuration can be simplified.

According to the fuel cell driving apparatus of the present invention, the execution timing determining means increases the dynamic pressure of the supply gas with a time lag for each cell unit, thereby recovering the wet state. As a result, the output voltage is gradually increased step by step.

According to the fuel cell driving device of the tenth aspect, since the inner surface of the groove portion in contact with the electrode surface is treated to be water repellent, excess water is unlikely to be accumulated in the groove portion. Therefore, the excess water can be blown off more easily by the increasing means.

[0026]

Preferred embodiments of the present invention will be described below in order to further clarify the structure and operation of the present invention described above.

FIG. 1 is a layout view of a fuel cell system 1 to which a first embodiment of a fuel cell driving apparatus of the present invention is applied. As shown in FIG. 1, the fuel cell system 1 includes a polymer electrolyte fuel cell 10 and a polymer electrolyte fuel cell 10.
An oxygen gas supply pipe 20 for sending the humidified material gas (oxygen or air), a bypass pipe 30 for bypassing the oxygen gas supply pipe 20, and a polymer electrolyte fuel cell 10
A gas discharge pipe 40 for sending the material gas discharged from the outside to the outside, and a control system 50 for controlling the flow rate of the bypass pipe 30 are provided.

The structure of the polymer electrolyte fuel cell 10 will be described below. Here, for simplicity, the case where the polymer electrolyte fuel cell 10 is composed of a single cell (one cell) will be described first. FIG. 2 is a structural diagram of a polymer electrolyte fuel cell 10 composed of unit cells, and FIG.
3 is an exploded perspective view of the polymer electrolyte fuel cell 10. FIG. As shown in these drawings, the polymer electrolyte fuel cell 10 includes an electrolyte membrane 110, a cathode 120 and an anode 130 as gas diffusion electrodes sandwiching the electrolyte membrane 110 from both sides, and the sandwich structure. Cathode 120 and anode 13 sandwiching them from both sides
And separators 140 and 150 that form flow paths for the material gas and the fuel gas, and collector plates 160 and 170 that are disposed outside the separators 140 and 150 and serve as collector electrodes for the cathode 120 and the anode 130. There is.

The electrolyte membrane 110 is an ion exchange membrane made of a polymer material, for example, a fluorine resin, and exhibits good electric conductivity in a wet state. The cathode 120 and the anode 130 are formed of carbon cloth woven from yarns of carbon fibers, and carbon powder carrying platinum or an alloy of platinum and another metal as a catalyst is carried on the carbon cloth. Is kneaded into the gap. The separators 140 and 150 are formed of a dense carbon plate. The separator 140 on the cathode 120 side forms a flow path for the oxygen-containing gas, which is a material gas, with the surface of the cathode 120 and the cathode 1
An oxygen gas flow path (corresponding to the above-mentioned cathode side gas flow path) 142 that forms a water collection path of the water generated in 20 is formed.
In addition, the separator 150 on the anode 130 side forms a hydrogen gas flow path 152 that forms a flow path of a mixed gas of hydrogen gas that is a fuel gas and water vapor with the surface of the anode 130. The collector plate 160 is made of copper (Cu).

What has been described above is the polymer electrolyte fuel cell 1
The basic configuration is 0. Next, the polymer electrolyte fuel cell 10 actually used will be described. FIG. 4 is a structural diagram showing an actual schematic structure of the polymer electrolyte fuel cell 10. In addition, in FIG. 4, parts having the same configurations as those in FIGS. 2 and 3 are denoted by the same reference numerals as those in FIGS.

As shown in FIG. 4, in the polymer electrolyte fuel cell 10, a plurality of unit cells 200 composed of the electrolyte membrane 110, the cathode 120 and the anode 130 shown in FIGS. It is a thing. This separator 210 is made of the same material as the separators 140 and 150 of the unit cell shown in FIGS. 2 and 3, and the surface of the cathode 120 of the unit cell 200 on one side forms the oxygen gas flow channel 1.
42, and the anode side 13 of the unit cell 200 on the other side
The surface of 0 forms a hydrogen gas flow path 152. In the figure, a separator 140 that forms only an oxygen gas flow path 142 is arranged outside the rightmost unit cell 200R, and a hydrogen gas flow path is formed outside the leftmost unit cell 200L. Separator 15 forming only 152
0 is placed.

Further, in the polymer electrolyte fuel cell 10, the cooling water channels 220 and 230 arranged outside the separators 140 and 150, and the current collector plate 160 arranged further outside the cooling water channels 220 and 230. , 170, and end plates 260, 270 sandwiching the whole from both sides via insulating plates 240, 250, and further, a tightening bolt 280 for tightening the end plates 260, 270 from the outside.

Returning to FIG. 1, the oxygen gas supply pipe 20, the bypass pipe 30, and the gas discharge pipe 40 will be described below. The oxygen gas supply pipe 20 is a pipe for supplying oxygen gas to the oxygen gas flow path 142 of the polymer electrolyte fuel cell 10, and is a manifold on the intake side of the polymer electrolyte fuel cell 10 from the oxygen gas supply source (see FIG. (Not shown). In the middle of the oxygen gas supply pipe 20, a first gas pressure regulating valve 22 and an MFC (Mass Flow Controller) 2 are arranged in order from the gas supply source side.
4, a humidifier 26 and a check valve 28 are provided.

The gas pressure regulating valve 22 is of a diaphragm type, and the flow rate can be adjusted to a constant value by operating the gas pressure regulating valve 22 at a predetermined opening degree in advance. The MFC 24 detects the mass flow rate of gas, and automatically controls the mass flow rate of gas arbitrarily according to a flow rate setting signal given from an external controller (not shown). The humidifier 26 humidifies the gas flowing through the oxygen gas supply pipe 20. A general bubbler type is used as the humidifier 26, and the humidifier 26 has a structure in which a supply gas is put into a tank that stores water and steam is added to the gas. With such a humidifier 26, it is difficult to suddenly change the humidification amount, and the dry gas is fed to the fuel cell 1.
When there is a request to supply 0, oxygen gas is supplied from the bypass pipe 30 side.

With the configuration of the oxygen gas supply pipe 20 as described above, the oxygen gas supplied from the gas supply source is adjusted to a predetermined flow rate by the first gas pressure regulating valve 22 and the MFC 24, and the oxygen of the solid polymer fuel cell 10 is adjusted. It is sent to the gas flow path 142.

The bypass pipe 30 is for feeding the oxygen gas (dry gas) sent from the oxygen gas supply source to the polymer electrolyte fuel cell 10 by bypassing the oxygen gas supply pipe 20. From the upstream side of the pressure valve 22, the check valve 28
It is a pipeline to the downstream side of. A second gas pressure regulating valve 32, an electric valve 34, a second gas pressure regulating valve 36, and a check valve 38 are provided in this bypass pipe 30 in this order from the upstream side. The motor operated valve 34 arbitrarily controls the flow rate according to the bypass opening signal given from the control system 50. With such a configuration of the bypass pipe 30, the flow rate of bypassing the oxygen gas supply pipe 20 is controlled by the control system 50.

The gas discharge pipe 40 is a pipe for sending the oxygen gas discharged from the oxygen gas flow passage 142 of the polymer electrolyte fuel cell 10 to the outside. A gas pressure control valve 42 is provided in the middle of the gas discharge pipe 40, and the pressure of the gas discharge pipe 40 is adjusted to a predetermined level by the gas pressure control valve 42.

The control system 50 will be described below. The control system 50 serves as a sensor for detecting the state of the polymer electrolyte fuel cell 10, and includes a voltmeter 52 for detecting the output voltage E of the polymer electrolyte fuel cell 10 and an impedance Z of the polymer electrolyte fuel cell 10. And an electronic control unit 60 connected to the voltmeter 52 and the impedance meter 54.

The voltmeter 52 is a normal DC voltmeter.
The impedance meter 54 is an AC interelectrode resistance meter so as not to affect the electrochemical reaction of the polymer electrolyte fuel cell 10. In addition, the measurement frequency of the alternating current in the impedance meter 54 is an optimum frequency, for example, 10
It becomes [kHz].

The electronic control unit 60 is constructed as a logic circuit centered on a microcomputer, and more specifically, the CPU 62 for executing predetermined arithmetic operations according to a preset control program, and the CPU 62 for executing various arithmetic processing. Output signals from the ROM 64 in which necessary control programs and control data are stored in advance, the RAM 66 in which various data necessary for executing various arithmetic processing in the CPU 62 are temporarily read and written, the voltmeter 52, and the impedance meter 54. Input processing circuit 68, C for inputting
An output processing circuit 69 for outputting a bypass amount setting signal to the motor-operated valve 34 according to the calculation result of the PU 62 is provided.

C of the electronic control unit 60 having such a configuration
The PU 62 determines the wet state of the cathode 120 of the polymer electrolyte fuel cell 10 from the output signals from the voltmeter 52 and the impedance meter 54, and the drive control of the motor-operated valve 34 is performed according to the determination result, so that the polymer electrolyte type The flow rate of oxygen gas supplied to the fuel cell 10 is controlled.

Next, the CPU 62 of the electronic control unit 60
The oxygen gas amount supply control processing executed by the above will be described based on FIG. When the process is started, the CPU 62 first reads the output voltage E detected by the voltmeter 52 and the impedance Z detected by the impedance meter 54 (steps S300 and S310). Next, a process of determining whether the surface of the cathode 120 of the polymer electrolyte fuel cell 10 is too wet is performed from the output voltage E and the impedance Z (step S320). Specifically, the output voltage E is a predetermined first predetermined voltage value E
First determination of whether or not less than 1 and impedance Z
A second determination whether or not is smaller than a predetermined impedance value Z1 determined in advance, and when both determinations are affirmative, it is determined that the cathode 120 is too wet.
It proceeds to step S330.

In step S330, the opening degree .theta. That determines the bypass amount setting signal sent to the motor-operated valve 34 is set to a predetermined opening degree .theta.c. The predetermined opening degree θc is an initial setting value θ0 (for example, θ0 = 0 when the routine is started.
[°]), and as a result, the opening degree θ of the motor-operated valve 34 is increased to θc. On the other hand, when it is determined in step S320 that the cathode 120 is not too wet, that is, when at least one of the first and second determinations is negative, step S300.
Then, the process after step S300 is repeatedly executed.

When the opening degree θ of the motor-operated valve 34 is increased in step S330, a process for determining whether or not the surface of the cathode 120 is excessively wetted is then performed (step S340). Specifically, the output voltage E detected by the voltmeter 52 becomes larger than a second predetermined voltage value E2 (E2> E1) that is set in advance, and the impedance Z detected by the impedance meter 54 is not too wet. When the impedance value Z0 during normal operation is restored,
It is determined that the excessive wetting of the surface of the cathode 120 has been eliminated. If it is determined in step S340 that the over-wetting has not been resolved, the process repeats step S340 and waits until the over-wetting is resolved. On the other hand, when it is determined that the surface of the cathode 120 is not too wet, the process proceeds to step S350. In step S350,
The opening degree θ that determines the bypass amount setting signal is set to the initial setting value θ0, and the processing for returning the opening degree θ of the electric valve 34 to the initial position is performed. After that, the process goes to "END" to end this processing.

With the oxygen gas amount supply control process thus configured, the output voltage E detected by the voltmeter 52, the impedance Z detected by the impedance meter 54, and the flow rate V of the oxygen gas flowing through the oxygen gas supply pipe 20 are changed over time. How it changes with the passage of will be described next with reference to the timing chart of FIG.

Now, it is assumed that the polymer electrolyte fuel cell 10 is in a normal state and outputs the output voltage E0 (time t0). The impedance at this time is Z0, and the flow rate V of the oxygen gas flowing through the oxygen gas supply pipe 20 is V0. From this state, if the surface of the cathode 120 of the polymer electrolyte fuel cell 10 becomes too wet for some reason, the output voltage E of the polymer electrolyte fuel cell 10 gradually decreases, and the impedance Z gradually increases. Fall to. The output voltage E is below the predetermined voltage E1, and the impedance Z is the first predetermined impedance value Z.
If it is less than 1 (time t1), an affirmative decision is made in step S320, and the operation proceeds to step S330, where the opening degree θ of the motor-operated valve 34 is increased to a predetermined opening degree θc. As a result, the flow rate V of the oxygen gas in the oxygen gas supply pipe 20 is increased by a predetermined amount from V0 to V1.

When the flow rate of oxygen gas is increased to V1, water droplets (excess water) condensed and attached on the surface of the cathode 120 of the polymer electrolyte fuel cell 10 are blown off by the dynamic pressure of the oxygen gas at the flow rate V1. The gas is discharged to the outside through the gas discharge pipe 40. Therefore, it is possible to prevent the pores on the surface of the cathode from being blocked by the water droplets, and the cathode portions that could not contribute to the electrochemical reaction due to the water droplets also start the electrochemical reaction. Therefore, the output voltage E of the polymer electrolyte fuel cell 10 starts to rise from E1. Further, as described above, the water droplets adhering to the surface of the cathode 120 are blown away by the dynamic pressure of oxygen gas, so that the cathode 120 comes out of the excessively wet state, and as a result, the impedance Z starts to rise from Z1.

After that, when the output voltage E and the impedance Z continue to rise and exceed E2 and E0 respectively (time t2), it is judged that the surface of the cathode 120 of the polymer electrolyte fuel cell 10 has returned from the wet state to the normal state. Then, in step S350, the opening degree θ of the motor-operated valve 34 is set to the initial setting value θ0.
Returned to. As a result, the flow rate V of the oxygen gas flowing through the oxygen gas supply pipe 20 returns from V1 to the original V0. In addition,
In this embodiment, the output voltage E0 in the steady state is
2 is larger, but this is the oxygen gas supply pipe 2
This is because oxygen gas is supplied to the polymer electrolyte fuel cell 10 from the bypass pipe 30 in addition to 0, and the magnitude of E2 changes depending on the amount of gas flowing through the bypass pipe 30.

As described above in detail, the fuel cell system 1 of the first embodiment can quickly blow off the water droplets adhering to the surface of the cathode 120 with the increased flow rate of oxygen gas. For this reason, the generated water on the surface of the cathode 120 can be removed with good responsiveness, and therefore electromotive force can be efficiently and continuously obtained from the polymer electrolyte fuel cell 10. In particular, in this embodiment, since the humidifier is not provided in the bypass pipe 30, the oxygen gas increased to blow off the water droplets is dry,
Therefore, in combination with the effect of blowing off, the generated water can be removed with higher responsiveness. Therefore, continuous electromotive force can be more efficiently obtained from the polymer electrolyte fuel cell 10. Further, since the fuel cell system 1 blows away water droplets by the dynamic pressure of oxygen gas, it is not necessary to use a material having low heat resistance as in the conventional example, and therefore the durability of the entire system is improved. It does not deteriorate.

Although the bypass pipe 30 is provided with the electric valve 34 and the gas pressure regulating valve 36 in the first embodiment, instead of this, as shown in FIG.
FC380 is provided, and bypass pipe 3 is provided by MFC380.
The mass flow rate of oxygen gas flowing through 0 may be controlled. With such a configuration, the same effect as that of the first embodiment can be obtained. In FIG. 7, parts having the same configurations as those in FIG. 1 are designated by the same reference numerals.

Next, a second embodiment of the present invention will be described. FIG. 8 is a layout diagram of a fuel cell system 400 to which a second embodiment of the fuel cell driving apparatus of the present invention is applied. As shown in FIG. 8, the fuel cell system 400 includes a first
The polymer electrolyte fuel cell 10 having the same structure as that of the embodiment, the oxygen gas supply pipe 20, and the gas discharge pipe 40 are provided, and the gas circulation pipe 430 is provided in place of the bypass pipe 30 of the first embodiment. The fuel cell system 400
Is also equipped with the same control system 50 as in the first embodiment, and the electronic control unit 60 provided in the control system 450 adjusts the gas circulation amount of the gas circulation pipe 430. Note that FIG.
Among them, the same reference numerals are given to parts having the same configurations as those in FIG.

The gas circulation pipe 430 is connected to the gas exhaust pipe 40.
From the connecting portion 40a between the polymer electrolyte fuel cell 10 and the gas pressure regulating valve 42 in FIG. 2 to the connecting portion 20 between the check valve 28 and the polymer electrolyte fuel cell 10 in the oxygen gas supply pipe 20.
It is a conduit for circulating oxygen gas toward a. In the middle of the gas circulation pipe 430, a circulation blower fan 432 and a check valve 434 are provided in this order from the connecting portion 40a side. The circulation blower fan 432 operates / stops the fan according to the control signal given from the electronic control unit 60. The check valve 434 prevents the gas from circulating from the oxygen gas supply pipe 20 side to the gas circulation pipe 430.

Next, the CPU 62 of the electronic control unit 60
The oxygen gas amount supply control processing executed by the above will be described with reference to FIG. Compared with that in the first embodiment, the oxygen gas amount supply control processing in the second embodiment is the same in the steps S500 to S520 and S540 as the steps S300 to S320 and S340 in the first embodiment. In step S330, the operation of the circulation fan 432 is started instead of step S330 (step S530).
Instead, the processing for stopping the circulation blower fan 432 is performed (step S550).

According to the oxygen gas amount supply control process thus constructed, the cathode surface of the polymer electrolyte fuel cell 10 is wetted from the output voltage E detected by the voltmeter 52 and the impedance Z detected by the impedance meter 54. When the excess is detected, the circulation blower fan 432 is started at the time of detection. When the circulation fan 432 is operated,
The amount of oxygen gas circulating through the gas circulation pipe 430 is increased by a predetermined amount determined by the operating capacity of the circulation blower fan 432, and as a result, the oxygen gas flow path 142 of the polymer electrolyte fuel cell 10 is increased by the increased amount. The flow rate of oxygen gas is increased. Therefore, the water droplets attached to the surface of the cathode 120 can be quickly blown off by the dynamic pressure of the oxygen gas at the flow rate. Therefore, similarly to the first embodiment, the generated water near the cathode 120 can be removed with good responsiveness, and electromotive force can be efficiently and continuously obtained from the polymer electrolyte fuel cell 10. Further, similar to the first embodiment, it also has an effect of preventing deterioration of durability of the entire system.

Further, in the second embodiment, the supply gas is supplied by circulating the oxygen gas discharged from the oxygen gas flow path 142 through the polymer electrolyte fuel cell 10 in spite of the above-mentioned effects. The consumption of can be suppressed.

In the second embodiment, the circulation blower fan 432 is operated / stopped to change the flow rate of the gas circulation pipe 430. However, instead of this, the circulation blower fan 432 is Alternatively, the circulation flow rate of the gas circulation pipe 430 may be changed by changing the rotation speed of the circulation blower fan 432 after the operation is always performed.

Next, a third embodiment of the present invention will be described. FIG. 10 is a layout diagram of a fuel cell system 600 to which a third embodiment of the fuel cell driving apparatus of the present invention is applied.
As shown in FIG. 10, the fuel cell system 600 is
The difference from the first embodiment is that the bypass pipe 30 is eliminated and an electric back pressure adjusting valve 642 is provided in the gas discharge pipe 640. In FIG. 10, parts having the same configurations as those in FIG. 1 are designated by the same reference numerals.

The electric back pressure adjusting valve 642 arbitrarily controls the opening according to the opening signal given from the electronic control unit 60 of the control system 50, and adjusts the gas pressure in the gas exhaust pipe 640. . When the opening degree of the electric back pressure adjusting valve 642 is increased, the gas pressure of the gas discharge pipe 640 is decreased, and as a result, the flow velocity of oxygen gas flowing through the oxygen gas flow path 142 of the polymer electrolyte fuel cell 10 is increased. Grows rapidly.
That is, the flow rate of oxygen gas can be changed by changing the opening degree of the electric back pressure adjusting valve 642.

Next, the CPU 62 of the electronic control unit 60
The oxygen gas amount supply control processing executed by the above will be described with reference to the flowchart of FIG. The oxygen gas amount supply control process in the third embodiment first detects excessive wetting of the surface of the cathode 120 of the polymer electrolyte fuel cell 10 as in steps S300 to S320 of the first embodiment (step S700). ~ S720).

After that, when the excessive wetness is detected, the electric back pressure adjusting valve 642 is controlled in the opening direction by a predetermined opening α to change the gas pressure P of the gas discharge pipe 640 from the pressure P0 during normal operation. A process of lowering P1 (however, P <P0) is performed (step S730). Then, the cathode 120
A process is performed to determine whether or not the surface is too wet (step S740). Specifically, the output voltage E is a third predetermined voltage value E3 (where E0> E3).
> E1) and the impedance Z detected by the impedance meter 54 is not too wet and returns to the impedance value Z0 during normal operation, it is determined that the overwetting of the surface of the cathode 120 has been eliminated. In step S740, the process waits until it is determined that the excessive wetting is eliminated, and then in step S730, the electric back pressure adjusting valve 6 is released.
A process of controlling the gas pressure P in the closing direction to restore the gas pressure P to the pressure P0 during normal operation is performed (step S750).
Then, this process is completed.

The timing chart of FIG. 12 shows how the output voltage E, the impedance Z, and the gas pressure P of the gas exhaust pipe 40 change with time by the oxygen gas amount supply control process thus configured. It was shown to.

Now, it is assumed that the polymer electrolyte fuel cell 10 is in a normal state and the output voltage E is E0 (time t0). The impedance Z at this time is Z0. The pressure P of the oxygen gas in the gas exhaust pipe 640 is P0 by adjusting the electric back pressure adjusting valve 642. From this state, when the surface of the cathode 120 of the polymer electrolyte fuel cell 10 becomes too wet, the output voltage E of the polymer electrolyte fuel cell 10 gradually decreases, and the impedance Z gradually decreases. . And the output voltage E
Is below a predetermined voltage E1 and the impedance Z is below a first predetermined impedance value Z1 (time t1
1), the gas pressure P decreases to P1 by controlling the electric back pressure adjusting valve 642 in step S730.

When the gas pressure P in the gas discharge pipe 640 drops to P1, the output voltage E temporarily drops due to the property of the polymer electrolyte fuel cell 10 that the output voltage E depends on the gas pressure P. Further, when the gas pressure P is lowered, the differential pressure between the inlet side of the polymer electrolyte fuel cell 10 increases momentarily, and therefore the flow velocity of the oxygen gas flowing through the oxygen gas flow path 142 increases rapidly. Become. As a result, the cathode 12
The water droplets adhering to the surface of 0 are blown off by the flow velocity thereof, and due to the same reason as in the first embodiment, the output voltage E increases only by the decrease in the output voltage E and starts increasing (time t12). The impedance Z is the time t1.
Immediately starts rising from 1.

After that, when the output voltage E and the impedance Z continue to rise, the output voltage E exceeds E3, and the impedance Z reaches the impedance value Z0 during normal operation (time t13), the polymer electrolyte fuel cell 10 It is determined that the surface of the cathode 120 has returned from the wet state to normal, and the pressure P is returned to the pressure P0 during normal operation by controlling the electric back pressure adjusting valve 642 in step S750.

According to the oxygen gas amount supply control process thus constructed, the wetting of the cathode surface of the polymer electrolyte fuel cell 10 from the output voltage E detected by the voltmeter 52 and the impedance Z detected by the impedance meter 54. When the excessiveness is detected, the gas pressure P on the gas discharge pipe 640 side is decreased at the time of the detection. When the gas pressure P is reduced, the flow velocity of the gas flowing through the oxygen gas flow path 142 of the polymer electrolyte fuel cell 10 rapidly increases. Therefore, the cathode 1
Water droplets adhering to the surface of 20 can be quickly blown off by the flow velocity of the oxygen gas. Therefore, similarly to the first and second embodiments, electromotive force can be efficiently and continuously obtained from the polymer electrolyte fuel cell 10. Further, similarly to the first and second embodiments, it also has an effect of preventing deterioration of durability of the entire system.

Further, in the third embodiment, the flow velocity of the oxygen gas flowing through the oxygen gas flow path 142 can be controlled only by providing the electric back pressure adjusting valve 642 in the gas discharge pipe 640, so that the structure is simple. It also has the effect of living.

In the third embodiment, the electric back pressure adjusting valve 642 is provided in the gas exhaust pipe 40. Instead of this, as shown in FIG. 13, the oxygen gas supply pipe 20 is electrically driven. The back pressure adjusting valve 642 may be provided. That is, as shown in FIG. 13, as in the first embodiment, the gas discharge pipe 40 is provided with the gas pressure regulating valve 42.
Then, an electric back pressure adjusting valve 642 is provided between the humidifier 26 and the check valve 28 in the oxygen gas supply pipe 20. With such a configuration, by adjusting the gas pressure of the oxygen gas supply pipe 20 with the electric back pressure adjusting valve 642,
The flow velocity of the oxygen gas flow path 142 of the polymer electrolyte fuel cell 10 can be changed. Therefore, the same effects as those of the first to third embodiments can be obtained.

Next, a fourth embodiment of the present invention will be described. FIG. 14 is a layout diagram of a fuel cell system 800 to which a fourth embodiment of the fuel cell driving apparatus of the present invention is applied.
As shown in FIG. 14, the fuel cell system 800 is
This is a combination of the structure of the first embodiment shown in FIG. 1 and the structure of the third embodiment shown in FIG. That is, the gas discharge provided with the solid polymer electrolyte fuel cell 10, the oxygen gas supply pipe 20, and the bypass pipe 30 having the same structure as the first embodiment, and the electric back pressure adjusting valve 642 having the same structure as the third embodiment. The pipe 640 is provided. In addition, in FIG.
The same reference numerals are given to parts having the same configurations as those in FIG.

According to the fourth embodiment thus constructed,
When excessive wetting of the cathode surface of the polymer electrolyte fuel cell 10 is detected, the electric valve 34 is opened to start the gas supply through the bypass pipe 30, and the electric back pressure adjusting valve 6
By 42, the gas pressure P on the gas discharge pipe 640 side is reduced. As a result, oxygen gas is supplied through the bypass pipe 30 in addition to the oxygen gas supply pipe 20,
Oxygen gas is sucked into the polymer electrolyte fuel cell 10 in response to the decrease in the gas pressure P on the gas discharge pipe 640 side. Therefore, the effects of both are added, and as a result, the flow rate of the oxygen gas flowing through the oxygen gas flow path 142 of the polymer electrolyte fuel cell 10 is rapidly increased.

As described above, the water droplets attached to the surface of the cathode 120 of the polymer electrolyte fuel cell 10 can be more surely blown off. Therefore, the cathode 1
The generated water in the vicinity of 20 can be removed more responsively, and electromotive force can be continuously obtained from the polymer electrolyte fuel cell 10 more efficiently and continuously.

Next, a fifth embodiment of the present invention will be described. FIG. 15 is a layout view of a fuel cell system 900 to which a fifth embodiment of the fuel cell driving apparatus of the present invention is applied.
As shown in FIG. 15, the fuel cell system 900 is
Compared with the first embodiment, a great difference is that a plurality of polymer electrolyte fuel cells 910 (hereinafter, this unit is referred to as a battery unit), which is an assembly of a plurality of unit cells, are provided, and a bypass pipe 930 is provided. It basically agrees with the point that the oxygen gas supply is increased by using.

That is, as shown in FIG. 15, this fuel cell system 900 includes n cell units 910-1, 910-2, 91 from the first to the n-th (n is an arbitrary positive number).
0-3, ..., 910-n and each battery unit 910-1
~ 910-n oxygen gas supply pipe 920 for sending oxygen gas
And a bypass pipe 930 that bypasses the oxygen gas supply pipe 920, and the battery units 910-1 to 910-
Gas exhaust pipe 9 for sending oxygen gas exhausted from n to the outside
40, and a control system 950 for controlling the flow rate of the bypass pipe 930 and the distribution destination thereof.

The oxygen gas supply pipe 920 includes a first gas pressure regulating valve 922 and a first MFC 92 in order from the oxygen gas supply source.
4 and a humidifier 926, and branches toward the first to nth battery units 910-1 to 910-n on the downstream side thereof. It should be noted that check valves 928-1 and 928-2 for prohibiting return of oxygen gas toward the oxygen gas supply source are provided in the middle of each connecting pipe from the branch point to each of the battery units 910-1 to 910-n. , 928-3, ..., 9
28-n are provided respectively.

The bypass pipe 930 is equipped with a second gas pressure regulating valve 932, a second MFC 934 and a flow path switch 936 in order from the oxygen gas supply source. Flow path switch 936
The bypass pipe 930 on the downstream side is branched in the direction toward each of the first to n-th battery units 910-1 to 910-n, and the flow path switch 936 determines which battery unit 910- 1 to 910-n, or selectively switched. The flow path switch 93
6 to each of the battery units 910-1 to 910-n, a check valve 938-1, 938-2, 93 for inhibiting the return of oxygen gas toward the oxygen gas supply source is provided in the middle of each connection pipe.
8-3, ..., 938-n are provided respectively.

The gas exhaust pipe 940 is provided for each of the first to nth.
Of the battery units 910-1 to 910-n are collected in one, and the check valves 944-1, 944-2, ..., 944-n are provided at each branch portion. Gas pressure regulating valves 942 are arranged at the gathering portions.

Similar to the first embodiment, the control system 950 mainly includes an electronic control unit 960, and further, as a sensor, the first to nth battery units 910-1.
To 910-n output voltages E (1) to E (n) are individually detected, and the impedance Z of each of the first to nth battery units 910-1 to 910-n.
An impedance meter 954 for individually detecting (1) to Z (n) is provided.

CPU 962 of electronic control unit 960
Performs the following processing while exchanging data with the ROM 964 and the RAM 966. That is, the electronic control unit 960 uses the output voltage E detected by the voltmeter 952.
From (1) to E (n) and the impedances Z (1) to Z (n) detected by the impedance meter 954, the wet state of the cathode of each battery unit 910-1 to 910-n is determined, and this determination result The MFC 934 and the flow path switch 936 are controlled according to the above, and the process of increasing the flow rate of the oxygen gas to the battery units 910-1 to 910-n that are in an excessively wet state is executed.

The oxygen gas amount supply control process executed by the CPU 962 will be described with reference to FIG. CPU
When the processing is started, the 962 first reads the output voltages E (1) to E (n) of the battery units 910-1 to 910-n detected by the voltmeter 952 (step S1000). , The impedances Z (1) to Z (n) of the battery units 910-1 to 910-n detected by the impedance meter 954 are read (steps S1000 and S1010), and then the variable i is initialized to 0.
(Step S1020), the variable i is incremented by 1 (step S1).
030).

Then, it is determined whether or not the cathode of the i-th battery unit 910-i is too wet based on the variable i (step S1040). This determination is based on the output voltage E (i) and the impedance Z detected by the voltmeter 952 and the impedance meter 654.
To determine whether the output voltage E (i) is excessively wet based on (i), specifically, the first determination as to whether the output voltage E (i) is smaller than a predetermined first predetermined voltage value E1 and the impedance Z ( i) is a predetermined impedance value Z1 determined in advance
The second judgment of whether or not it is smaller is executed, and when both judgments are affirmative, the i-th battery unit 910-
If the cathode of i is too wet, step S10
Go to 50.

In step S1050, the flow path switch 93
6 is controlled to switch the flow path of the bypass pipe 930 toward the i-th battery unit 910-i. Next, a process for setting the valve opening θ that determines the bypass amount setting signal to be sent to the MFC 934 to a predetermined opening θc (step S1060). This predetermined opening θc
Is larger than the initial setting value θ0 (for example, θ0 = 0 [°]) at the time of starting this routine. As a result,
The valve opening θ of the MFC 934 is increased to θc. On the other hand, if it is determined in step S1040 that the cathode of the i-th battery unit 910-i is not too wet, that is, if at least one of the first and second determinations is negative, then step S1030.
Then, the process after step S1030 is repeatedly executed.

When the valve opening degree θ of the MFC 934 is increased in step S1060, a process for determining whether excessive wetting of the surface of the cathode is eliminated is then performed (step S1070). Specifically, the output voltage E (i)
Is a second predetermined voltage value E2 (where E2
> E1) and the impedance Z detected by the impedance meter 54 is not too wet and returns to the impedance value Z0 during normal operation, it is determined that the overwetting of the cathode surface has been eliminated. Step S
If it is determined at 1070 that the over-wetting has not been resolved, the process repeats step S1070 and waits until the over-wetting is resolved. On the other hand, if it is determined that the excessive wetting of the cathode surface has been eliminated, step S108.
Go to 0. In step S1080, the opening θ that determines the bypass amount setting signal is set to the initial setting value θ0, and the MFC is set.
Processing for returning the valve opening θ of 934 to the initial position is performed.

Thereafter, the variable i is changed to the battery unit 910-1.
It is determined whether or not it is larger than a constant n indicating the number of ˜910-n (step S1090). Here, if a negative determination is made, the process returns to step S1030, the variable i is incremented by the value 1, and the process after step 1030 is performed on the next battery unit 910. On the other hand, step S10
If an affirmative decision is made at 90, it is assumed that the variable i has reached the constant n, and the process ends in "END" and terminates this control processing.

According to the oxygen gas amount supply control processing configured as described above, the CPU 962 detects the battery unit 910 whose cathode surface is too wet from among the n battery units 910-1 to 910-n. When done, MFC9
By controlling the switch 34 and the flow path switch 936, the flow path of the bypass pipe 930 is switched to the battery unit 910 that is in the over-wet state, and the flow rate is increased. Therefore, the flow rate of the oxygen gas supplied to the battery unit 910 in the over-wetted state is increased, so that the water droplets adhering to the cathode surface of the battery unit 910 are increased by the increased flow rate of the oxygen gas. It can be blown away, and the excessively wet condition can be recovered with good responsiveness. Therefore, the plurality of battery units 91
An electromotive force can be efficiently and continuously obtained for any of 0-1 to 910-n.

In the fifth embodiment, when it is determined that a plurality of battery units 910 among the first to nth battery units 910-1 to 910-n are in a state where the cathode is too wet. The wetness recovery process is sequentially performed for each battery unit in the excessively wet condition with a time lag. For this reason, each of the battery units 910-1 to 910-n can recover its wetness one by one when it becomes too wet, and thus the first to n-th battery units 910-1 to 910-n are assembled. As a whole fuel cell, each cell unit 910-1 to
It is possible to gradually and gradually increase the output voltage accompanying the recovery of the wetness of 910-n, and to suppress the sudden increase of the output voltage.

Next, a sixth embodiment of the present invention will be described. In the sixth embodiment, the fuel cell is composed of a plurality of cell units as in the fifth embodiment, and the oxygen gas discharged from the fuel cell is circulated to the supply side as in the second embodiment. It is something to try.

FIG. 17 is a layout diagram of a fuel cell system 1900 to which the sixth embodiment of the fuel cell driving apparatus of the present invention is applied. As shown in FIG. 17, the fuel cell system 1900 includes first to fourth cell units 910-1 to 910-n, an oxygen gas supply pipe 920, and a gas exhaust pipe 940, which have the same configuration as the fifth embodiment. A gas circulation pipe 1930 is provided in place of the bypass pipe 930 of the fifth embodiment. The fuel cell system 1900 also includes a control system 950 having the same configuration as that of the fifth embodiment, and an electronic control unit 960 provided in the control system 950 adjusts the gas circulation amount of the gas circulation pipe 1930. In FIG. 17, parts having the same configurations as those in FIG. 15 are designated by the same reference numerals.

The gas circulation pipe 1930 is the gas exhaust pipe 9
Oxygen gas is taken out from the branch point 940a of 40
To n-th battery units 910-1 to 910-n, respectively. In the middle of the gas circulation pipe 1930, a circulation blower fan 1934 and a flow path switch 1936 are provided in order from the branch point 940a side. The downstream side of the flow path switching unit 1636 has the same configuration as that of the fifth embodiment, and detailed description thereof will be omitted here. The circulation blower fan 1934 operates / stops the fan according to a control signal given from the electronic control unit 960.

Next, the CPU 9 of the electronic control unit 960
The oxygen gas amount supply control process executed by 62 will be described with reference to FIG. The oxygen gas amount supply control process in the sixth embodiment is different from that in the fifth embodiment in steps S2000 to S2050, S20.
70 and S2090, step S1 of the fifth embodiment.
000 to S1050, S1070, and S1090, and the process of starting the circulation blower fan 1934 is performed instead of step S1060 (step S2060) and step S108.
In place of 0, processing for stopping the circulation blower fan 1934 is performed (step S2080).

According to the oxygen gas amount supply control process thus constructed, the first to nth battery units 910-1 are used.
When the battery unit 910 that is too wet is detected from among the ˜910-n, the flow path switch 936 is controlled and the circulation blower fan 1934 is started, so that the battery unit 910 that is too wet is detected. The flow rate of the oxygen gas supplied toward is increased. As a result, in the fuel cell system 1900 of the sixth embodiment, similar to the fifth embodiment, a plurality of battery units 910-1 to 910-n are provided.
An electromotive force can be efficiently and continuously obtained for any of the above.

Next, a seventh embodiment of the present invention will be described. In the seventh embodiment, the fuel cell is composed of a plurality of cell units as in the fifth and sixth embodiments, and then the third embodiment is used.
As in the embodiment, an electric back pressure adjusting valve is provided in the gas discharge pipe of the fuel cell, and the electric back pressure adjusting valve is used to change the flow velocity of oxygen gas flowing to the cathode surface of the fuel cell. .

FIG. 19 is a layout diagram of a fuel cell system 2900 to which the seventh embodiment of the fuel cell driving apparatus of the present invention is applied. As shown in FIG. 19, this fuel cell system 2900 differs from the sixth embodiment in the following points.
First, after eliminating the gas circulation pipe 1930, first to n-th electric back pressure adjusting valves 2910-1, 2910-2, ..., 2910-n are provided in each branch passage of the gas discharge pipe 940. And, these electric back pressure adjusting valves 2910-1
2910-n to the electronic control unit 96 of the control system 950
Adjustable at 0. Further, in place of the voltmeter 952 of the fifth and sixth embodiments, a voltmeter 2952 for detecting the total output voltage ET of the first to nth battery units 910-1 to 910-n connected to each other is provided. In place of the impedance meter 2954, an impedance meter 2954 for detecting the total impedance ZT of the first to nth battery units 910-1 to 910-n is provided.

FIG. 2 shows the oxygen gas amount supply control processing executed by the CPU 962 of the electronic control unit 960.
A description will be given along the flowchart of No. 0. CPU962
When the process starts, first, the variable i is set to an initial value 0 (step S3000). Then, the voltmeter 29
Each battery unit 910-1 to 910- detected at 52
In addition to reading the total output voltage ET of n, each battery unit 910 detected by the impedance meter 954.
The total impedance ZT of −1 to 910-n is read (steps S3010 and S3020).

Subsequently, the first to nth battery units 9
It is determined whether at least one or more battery units among 10-1 to 910-n are too wet.
2 and the total output voltage ET and the total impedance ZT detected from the impedance meter 654 are used to make a determination (step S3030). Specifically, a first determination is made as to whether the total output voltage ET is smaller than a predetermined first predetermined voltage value ET1 and a determination is made as to whether the total impedance ZT is smaller than a predetermined predetermined impedance value ZT1. If both determinations are affirmative, it is determined that one of the battery units is too wet and the step S
Proceed to 3040.

In step S3040, the variable i is incremented by one. Subsequently, the i-th electric back pressure adjusting valve 2910-i based on the variable i is controlled in the opening direction by a predetermined opening α, and the electric back pressure adjusting valve 2910-i of the gas exhaust pipe 640 is attached. A process of reducing the partial gas pressure Pi from the pressure Pa during normal operation to Pb is performed (step S3050).

After that, the CPU 962 executes a delay process for delaying by a predetermined time (step S3060), and when the delay time elapses, the i-th electric back pressure adjusting valve 2910-i based on the variable i is opened for a predetermined time. The electric back pressure control valve 2 of the gas exhaust pipe 640 is controlled to be closed by a degree α.
A process of returning the gas pressure Pi of the attached portion of 910-i to the pressure Pa during normal operation is performed (step S307).
0).

Thereafter, the variable i is changed to the battery unit 910-1.
It is determined whether or not it is larger than a constant n indicating the number of ˜910-n (step S3080), and if a negative determination is made, the process returns to step S3030, and the processes after step S3030 are repeated. On the other hand, if an affirmative decision is made in step S3080, it is assumed that the variable i has reached the constant n, and "EN
Then, the control process is terminated by exiting to "D". Also, when a negative determination is made in step S3030, that is, when it is determined that none of the battery units 910-1 to 910-n is in an excessively wet state, the process ends in “END” and the control process ends.

According to the oxygen gas amount supply control process thus constructed, the CPU 962 determines whether or not any of the first to n-th battery units 910-1 to 910-n is in an excessively wet state. When it is determined from the total output voltage ET and the total impedance ZT that one of the battery units 910-1 to 910-n is in an excessively wet state, first, the first electric back pressure Regulator valve 2
910-1 is adjusted and its electric back pressure adjusting valve 2910-
The process of lowering the gas pressure P1 of the attached portion of No. 1 to Pb is executed for a predetermined time (after the predetermined time, the gas pressure P1
1 is returned to Pa). When the gas pressure P1 is reduced, the flow velocity of oxygen gas flowing through the oxygen gas flow path of the battery unit 910-1 provided upstream of the electric back pressure adjusting valve 2910-1 rapidly increases. Therefore, when the battery cell unit that is too wet is the first battery cell unit 910-1, the battery cell unit 910-
The water droplets attached to the cathode surface of No. 1 are quickly blown off by the flow velocity of the oxygen gas, and the battery unit 910
-1 is the optimum wet state.

After that, the second electric back pressure adjusting valve 29
10-2 is adjusted similarly, and the second battery unit 910
-2 is the optimum wet state. Then, the 3rd and 4th
The number of processing objects is increased like the second, and step S30
The process is continued until it is determined by 30 that all of the excessively wet condition has been resolved. With such a configuration, all the battery units 910 that are in an excessively wet state are in an optimum wet state, and as with the fifth and sixth embodiments, any of the plurality of battery units 910-1 to 910-n can be used. However, the electromotive force can be efficiently and continuously obtained.

Further, in the seventh embodiment, the wet state of the first to n-th battery units 910-1 to 910-n need not be individually detected, but can be detected as a total. The number of signals can be reduced, and the configuration of control processing can be simplified.

Next, a modification of the seventh embodiment of the present invention will be described. This modification has the same hardware configuration as that of the seventh embodiment, and is different from the seventh embodiment only in the content of the oxygen gas amount supply control process executed by the CPU 962 of the electronic control unit 960. Is.

Electronic control unit 96 in this modification
The oxygen gas amount supply control process executed by the CPU 962 of 0 will be described with reference to the flowchart of FIG. This oxygen gas amount supply control process is compared with the control process shown in the flowchart of FIG.
Immediately after 0, step S3055 is added, and step S3
The difference is that step S3075 is added immediately after 070, and the other points are the same.

In this oxygen gas amount supply control processing,
When it is determined in step S3030 that it is too wet, in step S3050, the i-th electric back pressure adjusting valve 2910-i based on the variable i is controlled in the opening direction by the predetermined opening α, and the gas exhaust pipe 640 is opened. Of the electric back pressure adjusting valve 29
After reducing the gas pressure Pi of the attached portion 10-i from the pressure Pa during normal operation to Pb, the next step S3055
Is processed. In step S3055, the other electric back pressure adjusting valves 2910-1 to 2910-i-1,291 excluding the i-th electric back pressure adjusting valve 2910-i.
0-i + 1 to 2910-n are controlled in the closing direction by a predetermined opening degree β (<< α), and the electric back pressure regulating valve 2
910-1 to 2910-i-1, 2910-i + 1 to 2910
A process of increasing the gas pressures P1 to Pi-1 and Pi + 1 to Pn in the attached portion of -n by small amounts is performed.

In step S3070, the i-th electric back pressure adjusting valve 2910-i based on the variable i is controlled in the closing direction by a predetermined opening α to adjust the electric back pressure of the gas exhaust pipe 640. Gas pressure P of the attached portion of the valve 2910-i
After i is returned to the pressure Pa at the time of normal operation, the process of the next step S3075 is performed. In step S3075, the other electric back pressure adjusting valves 2910-1 to 2910- except for the i-th electric back pressure adjusting valve 2910-i.
i-1,2910-i + 1 to 2910-n are set to a predetermined opening β
Control in the opening direction respectively, and the electric back pressure adjusting valves 2910-1 to 2910-i-1, 2910-i + 1 to 291 are controlled.
Gas pressures P1 to Pi-1 and Pi + 1 to Pn of the attached parts of 0-n
Is performed to restore the pressure Pa to the pressure Pa during normal operation.

According to the modified example of the seventh embodiment, as in the seventh embodiment, a plurality of battery units 910-1 to 9-10 are used.
In addition to the effect that the electromotive force can be efficiently and continuously obtained for any of 10-n, the following effects are also achieved.

FIG. 22 is a timing chart showing changes in the total output voltage ET in this modification. As shown in FIG. 22, at time t21, each battery unit 91
It is assumed that 0-1 to 910-n are normally operated and the total output voltage ET is at the predetermined voltage ET0. From this state, if the cathode surface of any of the battery units 910-1 to 910-n becomes too wet, the total output voltage ET sharply drops. When the oxygen gas amount supply control process by the CPU 962 is executed to reduce the back pressure of the battery unit 910 that is too wet for the first time,
The total output voltage ET gradually increases (time t22-
t23). After that, the total output voltage ET slightly rises with the control of returning the back pressure to the initial position (time t2).
3 to t24). Next, the same process is performed on the second and subsequent over-wet battery units 910, and the total output voltage ET gradually returns to the magnitude during normal operation.

From time t22 to t23, as described above, it is possible to reduce the gas pressure in the gas discharge pipe portion of the battery unit 910 which is too wet by using the electric back pressure adjusting valve. As described in the example, due to the property of the fuel cell that the output voltage depends on the gas pressure, the output voltage ET should drop once as shown by the alternate long and short dash line in the figure due to the pressure drop. On the other hand, in this modified example, the other electric back pressure adjusting valve is adjusted in step S3055 to increase the gas pressure in the attached portion of the electric back pressure adjusting valve by a small amount. The decrease of the total output voltage ET can be suppressed, and the fluctuation of the output voltage at the time of restoration can be suppressed, and smooth restoration processing can be performed. Therefore, the electromotive force can be obtained with higher efficiency.

In the seventh embodiment and its modification, all the battery units 910-1 from the 1st to the n-th.
The above-mentioned oxygen gas amount supply control processing has been performed in the set of ˜910-n.
The battery units 910-1 to 910-n may be divided into some groups and the oxygen gas amount supply control process described above may be performed in units of these groups. That is, the total output voltage and impedance are detected in each set unit, overwetting is detected from these detection results, and the dynamic pressure of the oxygen gas supplied to each battery unit is sequentially increased within the range of the set unit. To configure. Even with such a configuration, the same effects as those of the embodiments can be obtained.

In each of the above-mentioned embodiments, the dynamic pressure of the oxygen gas supplied to the cathode is increased.
Instead of this, in addition to the increase of the oxygen gas to the cathode, the dynamic pressure of the hydrogen gas supplied to the anode may be increased by the similar control. With such a configuration, it is possible to prevent the pores of the electrode base material on the anode side from being blocked, so that electromotive force can be obtained more efficiently and continuously. Note that the cathode side may be configured to increase only the dynamic pressure of the hydrogen gas supplied to the anode without controlling the increase of the dynamic pressure.

Further, the following configurations may be adopted in each of the above-described embodiments. 23 is a partial perspective view of the separator 140 that constitutes the oxygen gas flow path 142 together with the cathode surface, and FIG. 24 is a sectional view taken along the line AA in FIG. As shown in both figures, the oxygen gas flow path 142
Is formed on the inner surface of the rectangular groove portion 142a forming the
000 are formed. This Teflon layer 4000 is
The water-repellent material is formed as follows.

Of the surface of the separator 140, the cathode 1
A resist is applied in advance to the portion that directly contacts 20. Next, the entire separator 140 is made of a dispersion of polytetrafluoroethylene (polytetrafluoroethylene, the same as PTFE (Teflon)) (Polyflon D manufactured by Daikin Industries, Ltd.).
-1) Soak or spray dispersion. Then, it is dried at room temperature for a while to evaporate the solvent component (generally water or alcohol solvent or a mixed solvent of both) in the dispersion. next,
It is dried in air at 100 ° C. for 30 minutes to 1 hour to completely evaporate the water content of the dispersion. Further, in a nitrogen atmosphere or an argon atmosphere, heating is performed at 250 to 300 ° C. for 2 to 3 hours to calcine the polytetrafluoroethylene. In this way, a Teflon layer is formed on the surface of the separator 140.

Next, the resist previously applied in the previous step is removed by a chemical (resist remover). The resist remover used here differs depending on the type of the resist, and both the resist and the resist remover should not affect the process of forming the water repellent layer using the PTFE dispersion described above. For example, the user may arbitrarily select from the viewpoints of chemical cost, easiness of handling, easiness of treatment of used waste liquid, and the like.

With this structure, since the inner surface of the groove 142a is treated to be water repellent by the Teflon layer 4000,
Excess water does not easily collect in the groove 142a. Therefore, the excess water on the cathode surface as described above can be blown off more easily, and the electromotive force can be obtained more efficiently and continuously.

In the above embodiment, the Teflon layer 4 is used.
000 may be formed as follows. In the above-described embodiment, the portion of the surface of the separator 140 that is in direct contact with the cathode 120 is coated with the resist in advance and the dispersion is immersed. You may make it immerse in or may spray a dispersion. Then, the same treatment as in the above-described embodiment is performed to form a Teflon layer on the entire surface of the separator 140. Subsequently, of the surface of the separator 140, a portion which is in direct contact with the cathode 120 is mechanically polished or cut to remove the Teflon layer at that portion. In this way, the Teflon layer 4000 may be formed.

Further, in the above embodiment, the separator 140
The Teflon layer 4000 is formed in the oxygen gas flow path 142 formed in
However, instead of this, a similar Teflon layer may be provided in the hydrogen gas flow path 152 formed in the separator 150. With such a configuration, it is possible to more easily blow off excess water on the anode surface. Further, a configuration may be adopted in which a Teflon layer is provided in both the oxygen gas flow path 142 and the hydrogen gas flow path 152, and it is possible to easily blow off excess water on the cathode surface and the anode surface, and it is even more efficient and continuous. Electromotive force can be obtained.

In each of the embodiments described above, the cathode 12
The material gas supplied to 0 was oxygen, but instead of this, air may be used. When air is used, the amount of gas required to pass the same amount of current is larger than when oxygen is used, and therefore the possibility of excess water reaching the electrode surface is also higher in air. Therefore, when the material gas is air, the effect of the present invention is more exerted.

The embodiments of the present invention have been described above.
The present invention is not limited to these examples, and it goes without saying that the present invention can be implemented in various modes without departing from the scope of the present invention.

[0117]

As described above, in the first fuel cell driving apparatus of the present invention, when the electrode of the fuel cell is detected to be too wet, the dynamic pressure of the supply gas supplied to the electrode is temporarily stopped. The surplus water generated in the vicinity of the electrodes by the operation of the fuel cell is rapidly blown off by the increased dynamic pressure and discharged to the outside of the fuel cell. Therefore, it is possible to prevent the pores of the electrode base material from being clogged by the excess water with good response, and thus it is possible to efficiently and continuously obtain electromotive force from the fuel cell. Further, in this fuel cell drive device, since excess water is blown off by the dynamic pressure of the supply gas, it is not necessary to use a material with low heat resistance as in the conventional example, and therefore the durability of the entire system is improved. It also has an effect of preventing deterioration of the property.

Further, in this fuel cell driving apparatus, since the electromotive force can be efficiently obtained from the fuel cell as described above, a predetermined electric energy can be obtained in a smaller fuel cell and a lower cost fuel cell. Further, it has a secondary effect that it can be realized with a lighter fuel cell. Further, as described above, since a stable electromotive force can be continuously obtained from the fuel cell, it becomes easy to supply power only by the fuel cell without using it together with another power source such as a general commercial power source. It also has a secondary effect.

On the other hand, in the second fuel cell driving apparatus of the present invention, when it is detected that one of the cell units, which is an assembly of the unit cells, has too much electrode wetness, it is supplied to the electrode of the cell unit. Since the dynamic pressure of the supplied gas is temporarily increased, excess water generated in the vicinity of the electrode that has become over-wetted is
Due to the increased dynamic pressure of the supply gas, it is quickly blown away. Therefore, it is possible to prevent the pores of the electrode base material from being blocked by the excess water with good response, and it is possible to efficiently and continuously obtain the electromotive force for any of the plurality of battery units.

[Brief description of drawings]

FIG. 1 is a layout diagram of a fuel cell system 1 to which a first embodiment of a fuel cell driving apparatus of the present invention is applied.

FIG. 2 is a polymer electrolyte fuel cell 1 including a single cell.
FIG.

FIG. 3 is an exploded perspective view of the polymer electrolyte fuel cell 10.

FIG. 4 is a structural diagram showing an actual schematic structure of the polymer electrolyte fuel cell 10.

5 is a flow chart showing an oxygen gas amount supply control process executed by a CPU 62 of an electronic control unit 60. FIG.

FIG. 6 is a timing chart showing the operation of the oxygen gas amount supply control process.

FIG. 7 is a layout view showing a modified example of the first embodiment.

FIG. 8 is a layout view of a fuel cell system 400 to which a second embodiment of the fuel cell driving apparatus of the present invention is applied.

FIG. 9C of the electronic control unit 60 in the second embodiment
It is a flowchart which shows the oxygen gas amount supply control process performed by PU62.

FIG. 10 is a layout view of a fuel cell system 600 to which a third embodiment of the fuel cell driving apparatus of the present invention is applied.

FIG. 11 is a flowchart showing an oxygen gas amount supply control process executed by a CPU 62 of the electronic control unit 60 in the third example.

FIG. 12 is a timing chart showing the operation of the oxygen gas amount supply control process.

FIG. 13 is a layout view showing a modification of the third embodiment.

FIG. 14 is a layout view of a fuel cell system 800 to which a fourth embodiment of the fuel cell driving apparatus of the present invention is applied.

FIG. 15 is a layout view of a fuel cell system 900 to which a fifth embodiment of the fuel cell driving apparatus of the present invention is applied.

FIG. 16 is an electronic control unit 960 according to the fifth embodiment.
9 is a flowchart showing an oxygen gas amount supply control process executed by a CPU 962 of FIG.

FIG. 17 is a layout view of a fuel cell system 1900 to which a sixth embodiment of the fuel cell driving apparatus of the present invention is applied.

FIG. 18 is an electronic control unit 960 according to the sixth embodiment.
9 is a flowchart showing an oxygen gas amount supply control process executed by a CPU 962 of FIG.

FIG. 19 is a layout view of a fuel cell system 2900 to which a seventh embodiment of the fuel cell driving apparatus of the present invention is applied.

FIG. 20 is an electronic control unit 960 according to the seventh embodiment.
9 is a flowchart showing an oxygen gas amount supply control process executed by a CPU 962 of FIG.

FIG. 21 is a flowchart showing an oxygen gas amount supply control process in a modified example of the seventh embodiment.

FIG. 22 is a timing chart showing changes in the total output voltage ET in this modification.

FIG. 23 is a partial perspective view of an oxygen gas flow path 142 in contact with the cathode surface.

24 is a cross-sectional view taken along the line AA in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Fuel cell system 10 ... Polymer electrolyte fuel cell 20 ... Oxygen gas supply piping 22 ... First gas pressure regulating valve 24 ... MFC 26 ... Humidifier 28 ... Check valve 30 ... Bypass piping 32 ... Second gas conditioning Pressure valve 34 ... Motorized valve 36 ... Second gas pressure regulating valve 38 ... Check valve 40 ... Gas exhaust pipe 42 ... Gas pressure regulating valve 50 ... Control system 52 ... Voltmeter 54 ... Impedance meter 60 ... Electronic control unit 62 ... CPU 64 ... ROM 66 ... RAM 68 ... Input processing circuit 69 ... Output processing circuit 110 ... Electrolyte membrane 120 ... Cathode 130 ... Anode 140 ... Separator 142 ... Oxygen gas flow path 142a ... Groove 150 ... Separator 152 ... Hydrogen gas flow path 160, 170 ... Collection Electric plate 200 ... Single cell 210 ... Separator 220, 230 ... Cooling water flow path 240, 250 ... Insulating plate 260, 27 End plate 280 Bolt 380 MFC 400 Fuel cell system 430 Gas circulation piping 432 Circulation fan 434 Check valve 450 Control system 600 Fuel cell system 640 Gas exhaust piping 642 Electric back pressure Regulator valve 654 ... Impedance meter 800 ... Fuel cell system 900 ... Fuel cell system 910 ... Battery unit 920 ... Oxygen gas supply pipe 922 ... First gas pressure regulating valve 924 ... First MFC 926 ... Humidifier 928 ... Check valve 930 Bypass pipe 932 ... Second gas pressure regulating valve 934 ... MFC 936 ... Flow path switching device 938 ... Check valve 940 ... Gas discharge pipe 942 ... Gas pressure regulating valve 944 ... Check valve 950 ... Control system 952 ... Voltmeter 954 ... Impedance meter 960 ... Electronic control unit 962 ... CPU 964 ROM 966 ... RAM 1636 ... Flow path switch 1900 ... Fuel cell system 1930 ... Gas circulation piping 1934 ... Circulation blower fan 1936 ... Flow path switch 2900 ... Fuel cell system 2910 ... Electric back pressure adjusting valve 2952 ... Voltmeter 2954 ... Impedance meter 4000 ... Teflon layer E ... Output voltage ET ... Total output voltage Z ... Impedance ZT ... Total impedance

Claims (10)

[Claims] 1. A drive device for a fuel cell, which supplies gas to an electrode to obtain electromotive force from a chemical reaction of the supplied gas, comprising: an electrode wet state detecting means for detecting a wet state of the electrode; A driving device for a fuel cell, comprising: a dynamic pressure increasing means for temporarily increasing the dynamic pressure of the supply gas supplied to the electrode when the state detecting means detects the excessively wet state of the electrode. 2. The drive device for a fuel cell according to claim 1, wherein the dynamic pressure increasing means is a circulation means for circulating an exhaust of the supply gas from the fuel cell to the fuel cell, and the circulation means. And a circulation amount adjusting means for changing the circulation amount of gas by the means. 3. The drive device for a fuel cell according to claim 1, wherein the dynamic pressure increasing means discharges the supply gas from the gas supply path for supplying the supply gas to the fuel cell or the fuel cell. A drive device for a fuel cell, which is provided in a gas discharge path for controlling the gas pressure and has gas pressure adjusting means for adjusting the gas pressure in the gas path. 4. The drive device for a fuel cell according to claim 1, wherein a gas supply path for supplying a supply gas to the fuel cell, and a humidifier provided in the gas supply path for humidifying the supply gas. And a dynamic flow increasing means for bypassing the gas supply path to supply a dry supply gas to the fuel cell, and a bypass flow rate control means for controlling a flow rate of the bypass path. A fuel cell driving device having the same. 5. A drive device for a fuel cell, comprising a plurality of battery units each of which is an assembly of unit cells for supplying gas to an electrode to obtain electromotive force from a chemical reaction of the supplied gas, wherein the electrode is in a wet state. And an electrode wet state detecting means for detecting the wet state of the electrode in one of the battery units when the electrode wet state detecting means detects the excessive wet state of the electrode. And a driving device for a fuel cell, which temporarily increases the dynamic pressure. 6. The fuel cell drive device according to claim 5, wherein the dynamic pressure increasing means targets the increase in the dynamic pressure of the supply gas to at least a battery unit including the electrode that is too wet. A fuel cell drive, which is a means including a plurality of battery units including. 7. The drive device for a fuel cell according to claim 5, wherein the dynamic pressure increasing means includes a plurality of battery units that increase the dynamic pressure of the supply gas when the battery units are provided. A drive device for a fuel cell, comprising an execution timing determining means for increasing the dynamic pressure of the supply gas with a time lag. 8. The drive device for a fuel cell according to claim 7, wherein the dynamic pressure increasing means is provided in an exhaust passage of each of the cell units for exhausting the supply gas, and the gas in the exhaust passage is exhausted. When a state in which one of the battery units is overwetted is detected by the electrode wetting state detecting unit and a gas pressure adjusting unit that adjusts the pressure, the gas pressure adjusting unit corresponding to the battery unit is adjusted. This temporarily increases the dynamic pressure of the supply gas supplied to the electrode of the battery unit, and adjusts the gas pressure adjusting means corresponding to at least one of the other battery units other than the battery unit. A drive device for a fuel cell having a control means for temporarily reducing the dynamic pressure of the supply gas supplied to the electrodes of these cell units. 9. The drive device for a fuel cell according to claim 1, wherein the electrode is a cathode. 10. The drive device for a fuel cell according to claim 1, wherein the fuel cell includes a groove portion that is in contact with the electrode surface and supplies gas to the electrode, and an inner surface of the groove portion. A water-repellent fuel cell drive device.