JP2008016282A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell with a simple configuration which can restrict abnormal state of a reacting zone without the need of another power supply. <P>SOLUTION: The fuel cell includes a fuel power generator 2 which generates electricity by supplied fuel, a fuel tank 3 storing the fuel, a fuel supply passage 6 which supplies the fuel stored in the fuel tank to the fuel power generator, and a fuel supply valve 5 which is disposed at the fuel supply passage and controls the supply of the fuel. Further, the fuel cell includes a sensor 11 detecting an abnormal state of the fuel power generator, and a control unit 10 which opens and closes the fuel supply valve disposed at the fuel supply passage to control the supply of the fuel based on the presence of the abnormal information detected by the sensor section. Each of the sensor, the control unit, and the fuel supply valve can be configured to operate by electric power generated in the fuel generator. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel cell.

Since the fuel cell directly converts chemical energy obtained by chemically reacting fuel such as hydrogen or methanol with oxygen into electric energy, high power generation efficiency can be obtained.
Moreover, since there are few mechanical drive parts, it has the characteristics that a noise is very small and size reduction is possible.
Examples of small fuel cells include solid polymer fuel cells, and those used as power sources for portable devices such as notebook computers and mobile phones have been devised.
This is used in place of a primary battery such as an alkaline battery or a secondary battery such as a nickel ion battery, and can be used by being mounted on an electric device.

  A fuel cell generates electricity by an electrochemical reaction. A countermeasure when this electrochemical reaction deviates from design conditions for some reason and becomes abnormal is very important. Examples of abnormal electrochemical reactions include the case where the temperature of the reaction part becomes too high due to the heat generated by the reaction, or when an excessive current flows and a counter electromotive force is applied to a part of the reaction part. Can be mentioned.

The fuel cell electrochemical reaction becomes a problem when the temperature becomes too high for the following reasons.
Since the electrochemical reaction of a fuel cell is an exothermic reaction, it is necessary to dissipate heat during power generation.
If the heat dissipation during power generation is hindered for some reason, or if the amount of power generation increases sharply due to a short circuit between the positive and negative electrodes of the fuel cell, the heat dissipation during power generation will not be in time and the temperature inside the fuel cell will rise. Too much.
If the temperature inside the fuel cell becomes too high, problems such as deterioration of members constituting the fuel cell and a decrease in power generation efficiency due to changes in member characteristics occur.
The predetermined temperature varies depending on the type of electrolyte used in the fuel cell. For example, the solid polymer type is about 80 ° C., the phosphoric acid type is about 200 ° C., the molten carbonate type is about 650 ° C., and the solid oxide is used. In the mold, it is about 1000 ° C.

Conventionally, as a countermeasure when the temperature rises excessively during power generation as described above, for example, Patent Document 1 discloses an invention that suppresses heat generation during power generation as follows.
That is, an invention is disclosed in which a thermally decomposable polymer is incorporated in a stack in which an electrochemical reaction during power generation occurs, and when the temperature in the stack rises excessively, heat generation is suppressed by decomposition of the polymer.
For relatively large fuel cells, such as stationary fuel cells, prepare another power source to monitor the power generation status inside the fuel cell using a sensor. Some measures are taken to stop the fuel supply to the fuel cell using a simple power source.
JP-A-11-154521

However, countermeasures against abnormal conditions such as excessive temperature rise during power generation and excessive current flow in the conventional fuel cell described above have not always been satisfactory.
For example, in Patent Document 1, when the temperature during power generation rises, the polymer contained in the stack is decomposed in order to lower the temperature. For this reason, even if the temperature falls, the fuel cell does not return to the same state as before the rise, and there may be a case where the use of the fuel cell is hindered.
In addition, in the case where the conventional power source is provided and the fuel supply is stopped when an abnormal state is detected by the sensor, it is necessary to separately provide the fuel cell with another power source such as a secondary battery. For this reason, there arises a disadvantage that the apparatus is increased in size and cost. In particular, if this method is used in a small-sized fuel cell such as a portable one, it will be a great obstacle.

  In view of the above problems, an object of the present invention is to provide a fuel cell that does not require a separate power source and that can suppress an abnormal state of a reaction section with a simple configuration.

In order to solve the above-described problems, the present invention provides a fuel cell configured as follows.
The fuel cell of the present invention comprises
A fuel power generation unit that generates electric power using the supplied fuel; a fuel tank unit that stores the fuel; a fuel supply passage for supplying the fuel stored in the fuel tank unit to the fuel power generation unit; and the fuel supply A fuel supply valve for controlling the supply of fuel provided in the flow path;
A fuel cell comprising:
A sensor unit for detecting an abnormality of the fuel power generation unit;
Based on the presence or absence of abnormality information detected by the sensor unit, a control unit that opens and closes the fuel supply valve provided in the fuel supply channel and controls the supply of the fuel;
Each of the sensor unit, the control unit, and the fuel supply valve is configured to be operable by electric power generated in the fuel power generation unit.
In the fuel cell of the present invention, the sensor unit that detects an abnormality of the fuel power generation unit is a sensor that detects an abnormality of the temperature of the fuel power generation unit.
The fuel cell of the present invention is characterized in that the sensor unit that detects an abnormality of the fuel power generation unit is a sensor that detects an abnormality of the output current amount of the fuel cell.
In the fuel cell of the present invention, the fuel tank portion is a fuel tank containing a hydrogen storage alloy.

  According to the present invention, it is possible to suppress the abnormal state of the reaction unit with a simple configuration without requiring a separate power source.

In the embodiment of the present invention, the fuel cell of the present invention can be specifically configured as follows.
That is, the fuel cell according to the present embodiment includes a fuel tank section for storing hydrogen fuel, a fuel power generation section that generates power using the fuel, and a fuel supply flow path for supplying the fuel to the fuel power generation section. Prepare. And it can be set as the structure provided with the fuel supply valve which is in the middle of a fuel supply flow path and controls opening and closing of the fuel supply flow path.
At this time, the fuel cell is configured to open and close the fuel supply valve provided in the fuel supply flow path based on the presence or absence of a sensor unit that detects abnormality of the fuel power generation unit and abnormality information detected by the sensor unit. And a controller for controlling the supply of the fuel. And each of the said sensor part, the said control part, and the said fuel supply valve is comprised so that it can operate | move with the electric power which generate | occur | produced in the said fuel electric power generation part.
Thus, when the sensor unit detects an abnormality, the fuel supply valve is closed to stop the power generation of the fuel cell power generation unit, and when the abnormal state is released, the fuel supply is returned to the normal state again. .
According to the configuration of the present embodiment described above, it is possible to prevent the electrochemical reaction of the reaction unit that is a fuel power generation unit from becoming abnormal with a simple configuration that does not particularly require a separate power source such as a secondary battery. It becomes possible.

Examples of the present invention will be described below.
[Example 1]
In Example 1, a configuration example of a fuel cell to which the present invention is applied and an abnormal state of a reaction unit is detected by a temperature sensor will be described.
FIG. 1 is a block diagram for explaining the configuration of a fuel cell in Example 1 of the present invention.
In FIG. 1, 1 is a fuel cell, 2 is a fuel power generation unit, 3 is a fuel tank unit, 4 is a fuel tank mounting means, 5 is a fuel cutoff valve, 6 is a fuel supply flow path, 7 is a reaction unit, and 9 is a power supply terminal. Reference numeral 10 denotes a control unit, and 11 denotes a temperature sensor unit. In addition, 8 shows the flow of electricity from the reaction part.

The fuel cell 1 according to the present embodiment includes a fuel power generation unit 2 for generating electricity from fuel and a fuel tank unit 3 for storing fuel.
The fuel tank unit 3 is filled with a hydrogen storage alloy and stores hydrogen.
The fuel tank portion 3 has a structure that can be attached and detached by a tank attachment means 4.
The fuel supply channel 6 is a channel for supplying hydrogen gas from the fuel tank unit 3 to the reaction unit 7 of the fuel power generation unit, and a fuel cutoff valve 5 for blocking the supply of fuel is provided in the middle of the channel. Is provided.
The fuel cutoff valve 5 is a valve that can be electrically controlled to open and close, such as an electromagnetic valve. The fuel shut-off valve is open when power for shutting off the valve is not supplied, but when the power for shutting off the valve is supplied, the fuel shut-off valve is opened and closed by a signal from the control unit 10 described later. Be controlled.
In the reaction unit 7, an electrochemical reaction for power generation of the fuel cell is performed.

The electric power generated by the reaction unit is supplied to the power supply terminal 9 and is also supplied to the control unit 10 and the sensor unit 11 (the flow of electricity to the sensor unit is omitted in the figure).
Moreover, the electric power generated in the reaction unit is also used as electric power necessary for shutting off the fuel cutoff valve (the flow of electricity to the fuel cutoff valve is omitted in the figure). The control unit 10 is connected to the sensor unit 11 and the fuel cutoff valve via the signal line 12 and controls the opening and closing of the fuel cutoff valve according to the signal of the sensor unit by the processing of the flowchart of FIG. 4 described later.
The temperature sensor unit 11 measures the temperature of the reaction unit and transmits the information to the control unit 10. Based on the information of the temperature sensor unit 11, it is possible to detect whether or not the reaction unit is at a predetermined temperature or higher and it is inappropriate to continue power generation.

FIG. 2 is a perspective view for explaining the appearance of the fuel cell in the present embodiment. In the figure, reference numeral 14 denotes an air intake port that takes in air that is required when the reaction portion 7 causes an electrochemical reaction of fuel.
FIG. 3 is a schematic cross-sectional view of the inside of the fuel cell in the present embodiment.
The reaction part 7 is divided into two parts, and hydrogen is supplied from the fuel tank part to each reaction part by the fuel supply flow path 6.
The electric power generated by the two reaction units 7 is connected in series by electrical wiring (not shown) and supplied to the power supply terminal 9 and each element (the control unit 10 or the like) inside the fuel cell.

Next, the cutoff process by the fuel cutoff valve in the present embodiment will be described.
FIG. 4 shows a flowchart for explaining the shut-off process by the fuel shut-off valve in this embodiment.
While the reaction unit 7 of the fuel cell generates power and supplies power to an external device, the control unit 10 operates using a part of the generated power.
The controller 10 monitors the reaction temperature of the reaction part detected by the temperature sensor part 11 provided adjacent to the reaction part 7 (step S01).
When the temperature of the reaction part detected from the temperature sensor part 11 is within a normal range (in the case of N in step S01), monitoring of the detection value by this temperature sensor is continued. When the detected value by the temperature sensor has some abnormality in the electrochemical reaction of the reaction part and becomes a temperature higher than a predetermined temperature (abnormal detection value) (in the case of Y in step S01), the fuel to the reaction part Stop supplying.
That is, the control unit 10 issues a valve cutoff signal to the fuel cutoff valve, closes the valve (step S02), and stops the fuel supply to the reaction unit.

When the fuel supply is stopped, the reaction unit 7 gradually reduces the electrochemical reaction while consuming the fuel remaining in the reaction unit. However, while the power generation continues and the control unit 10 operates, the control unit The temperature of the reaction part detected from the part 11 is monitored (step S03).
When the detected value by the temperature sensor unit 11 returns to normal because the electrochemical reaction is weakened (in the case of Y in step S03), a valve cutoff release signal is output to the fuel cutoff valve and the valve is opened (step S05).
In addition, when the detected value by the temperature sensor unit 11 does not return to normal in step S03 (in the case of N in step S03), the state where the fuel supply is cut off continues.
As a result, when the power generation in the reaction unit is completely stopped (in the case of Y in step S05), the power supply necessary for shutting off the valve of the fuel cutoff valve 5 cannot be supplied from the reaction unit 7, and the fuel cutoff valve is automatically (Step S05).
If power generation in the reaction part is still continued in step S04 (in the case of N in step S04), the process returns to step S02 and the above process is repeated.
When the fuel shut-off valve is opened in step S05, the fuel in the fuel tank is automatically supplied to the reaction unit by a well-known method.
Then, the electrochemical reaction of the reaction unit 7 is performed as usual, and the process returns to step S01 again, and the control unit 10 monitors the detection value by the temperature sensor unit 11.
By this processing, the fuel supply is automatically adjusted so that the detection value by the temperature sensor unit 11 does not become abnormal, and thereby it is possible to realize a fuel cell in which the abnormality of the reaction unit is suppressed.

[Example 2]
In the second embodiment, not only the temperature sensor as in the first embodiment but also a configuration example using a sensor capable of detecting an abnormality in the reaction unit will be described.
FIG. 5 is a block diagram for explaining the configuration of the fuel cell in this embodiment. The same components as those in the first embodiment are denoted by the same reference numerals, and the description of the overlapping parts is omitted.
The sensor in this embodiment is not limited to a temperature sensor, but any sensor can be used as long as it can detect an abnormality in the reaction part. Here, a sensor for monitoring the amount of current output by the electrochemical reaction in the reaction part is provided. A configuration example will be described.

In FIG. 5, reference numeral 15 denotes a sensor unit in the second embodiment, which is an ammeter for detecting the amount of current supplied from the reaction unit 7 to the power supply terminal 9, and the detected information is transmitted to the control unit via the signal line 12. 10 is sent.
The appearance of the fuel cell in Example 2 is the same as that in Example 1.
The cross-sectional schematic diagram inside the fuel cell in Example 2 is also the same as that in Example 1. However, unlike Example 1, the sensor part is provided in the middle of the power supply wiring from the reaction part to the output terminal.

In the first embodiment, the abnormality of the sensor detection value is determined on the basis of being equal to or higher than the predetermined temperature. In the second embodiment, the abnormality of the sensor value is determined on the basis of being equal to or higher than the predetermined current amount. .
Except for this point, the fuel valve shut-off process in the second embodiment is performed as shown in the flowchart of FIG.
By this processing, as in the first embodiment, the fuel supply is automatically adjusted so that the detection value by the sensor does not become abnormal, and abnormality in the reaction unit is suppressed.

The block diagram for demonstrating the structure of the fuel cell in Example 1 of this invention. The perspective view for demonstrating the external appearance of the fuel cell in Example 1 of this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. The flowchart for demonstrating the cutoff process by the fuel cutoff valve in Example 1 of this invention. The block diagram for demonstrating the structure of the fuel cell in Example 2 of this invention.

Explanation of symbols

1: Fuel cell 2: Fuel power generation unit 3: Fuel tank unit 4: Fuel tank mounting means 5: Fuel cutoff valve 6: Fuel supply flow path 7: Reaction unit 9: Power supply terminal 10: Control unit 11: Temperature sensor unit 14: Air intake 15: Sensor unit (Ammeter for detecting the amount of current)

Claims (4)

A fuel power generation unit that generates electric power using the supplied fuel; a fuel tank unit that stores the fuel; a fuel supply passage for supplying the fuel stored in the fuel tank unit to the fuel power generation unit; and the fuel supply A fuel supply valve for controlling the supply of fuel provided in the flow path;
A fuel cell comprising:
A sensor unit for detecting an abnormality of the fuel power generation unit;
Based on the presence or absence of abnormality information detected by the sensor unit, a control unit that opens and closes the fuel supply valve provided in the fuel supply channel and controls the supply of the fuel;
Each of the sensor unit, the control unit, and the fuel supply valve is configured to be operable by electric power generated in the fuel power generation unit.   The fuel cell according to claim 1, wherein the sensor unit that detects an abnormality of the fuel power generation unit is a sensor that detects an abnormality of the temperature of the fuel power generation unit.   2. The fuel cell according to claim 1, wherein the sensor unit that detects abnormality of the fuel power generation unit is a sensor that detects abnormality of an output current amount of the fuel cell. 3.   The fuel cell according to any one of claims 1 to 3, wherein the fuel tank portion is a fuel tank containing a hydrogen storage alloy.

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