JP2002313397A - Cell burnout detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cell burnout detector capable of immediately detecting the burnout of a cell. SOLUTION: Transparent pipe parts 21a and 22a are provided in a fuel gas outlet pipe 21 or an oxidizing gas outlet pipe 22 or the gas outlet pipe 21 and the oxidizing gas outlet pipe 22 connected to a fuel cell stack 10, and an optical sensor 23 is installed in the transparent pipe parts 21a and 22a. A reduction in transparency of fluid flowing through the transparent pipe parts 21a and 22a caused by carbon (soot) discharged from the fuel gas outlet pipe 21 or oxidizing gas outlet pipe 22 or the fuel gas outlet pipe 21 and oxidizing gas outlet pipe 22 when the cell of the fuel cell stack 10 is burned out is detected by the optical sensor 23 to detect the burnout of the cell.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cell burnout detection apparatus, which is useful, for example, when detecting cell burnout in a polymer electrolyte fuel cell (PEFC).

[0002]

2. Description of the Related Art FIG. 3A is a structural view of a cell and a separator, and FIG. 3B is a structural view of a fuel cell stack. As shown in FIG. 3A, the cell 1 has a structure in which an ion exchange resin membrane is used as an electrolyte membrane 2 and the electrolyte membrane 2 is sandwiched between a fuel electrode 3 and an oxygen electrode 4 which are electrodes. Separator 5 is arranged on both sides of 1. The separator 5 has a fuel gas passage 6 for supplying a fuel gas (hydrogen-rich gas obtained by reforming fuel such as hydrogen or methanol) to the fuel electrode 3 of the cell 1, and an oxidizing gas flowing to the oxygen electrode 4 of the cell 1. Oxidizing gas passage 7 for supplying (oxygen or air, etc.)
And a cooling water passage 8 through which cooling water for cooling the cell 1 flows.
Are formed separately from each other.

[0003] As shown in FIG. 3B, a large number of cells 1 are stacked with a separator 5 interposed therebetween to form a fuel cell stack (cell stack) 10. End plates (flanges) 17 and 18 are provided at both ends of the fuel cell stack 10 in the cell stacking direction. One end plate 17 has a fuel gas introduction hole 11, an oxidizing gas introduction hole 12, and a cooling water introduction hole 13. The other end plate 18 has a fuel gas discharge hole 14, an oxidizing gas discharge hole 15, and a cooling water discharge hole 16.

[0004] In the fuel cell stack 10, a large number of cells 1 are electrically connected in series by a separator 5 that is a conductor, so that a desired voltage can be obtained as a whole of the fuel cell stack. Conventionally, in such a fuel cell stack 10, when the cell 1 is burned due to a sudden opening of the cell 1 for some reason during power generation and a rapid reaction between the fuel gas and the oxidizing gas, the cell voltage is monitored by a voltage monitor. By detecting a decrease in power generation, the burnout of the cell 1 was recognized, and power generation was stopped.

[0005]

However, in the method of detecting a drop in cell voltage, the detection of burnout of the cell 1 may be delayed. If the detection of burnout of the cell 1 is delayed, other normal cells 1 are also abnormally heated due to the effect of the burnt cell, and the power generation performance is reduced. If the fuel gas side and the oxidizing gas side have different pressures, the cell burnout may occur. Due to the pressure change due to the cross leak between the fuel gas and the oxidizing gas, a secondary problem occurs, for example, the pressure on the fuel gas outlet side increases and the fuel gas is not supplied.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a cell burnout detecting device capable of immediately detecting cell burnout in view of the above situation.

[0007]

Means for Solving the Problems Since components such as the fuel electrode 3 and the oxygen electrode 4 constituting the cell 1 contain carbon, if the cell 1 is burned out, the fuel gas discharge hole 14 or the oxidizing gas discharge hole is formed. Carbon (soot) flows out from the fuel gas discharge hole 15 or the fuel gas discharge hole 14 and the oxidizing gas discharge hole 15, and the fluid transparency is reduced. The cell burnout detection device of the present invention has been made by paying attention to this, and has the following configuration.

That is, in the cell burnout detecting apparatus according to the first aspect of the present invention which solves the above-mentioned problems, the fuel gas outlet pipe or the oxidizing gas outlet pipe connected to the fuel cell main body, or the fuel gas outlet pipe and the oxidizing gas outlet pipe are provided with a transparent pipe portion. In addition, an optical sensor is provided in the transparent pipe section, and flows through the transparent pipe section by carbon discharged from the fuel gas outlet pipe or the oxidizing gas outlet pipe or the fuel gas outlet pipe and the oxidizing gas outlet pipe when the fuel cell body is burned. The burnout of the cell is detected by detecting the decrease in the transparency of the fluid by an optical sensor.

Further, a cell burnout detecting device according to a second invention is characterized in that in the cell burnout detecting device according to the first invention, the fuel cell main body is a fuel cell stack formed by stacking a plurality of cells.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. Note that the configuration of the fuel cell stack is the same as that of the conventional fuel cell stack (see FIG. 3), and a description thereof will be omitted.

FIG. 1 is a schematic diagram of a fuel cell power generation system provided with a cell burnout detecting device according to an embodiment of the present invention, and FIG.
FIG. 3 is an explanatory view of the cell burnout detection device.

As shown in FIG. 1, a fuel gas introduction hole 11, an oxidizing gas introduction hole 12, and a cooling water introduction hole 13 provided at one end of a fuel cell stack (cell stack) 10 as a fuel cell main body are provided with fuel. The gas inlet pipe 25, the oxidizing gas inlet pipe 26, and the cooling water inlet pipe 27 are connected to each other.

The fuel gas inlet pipe 25 is connected to a fuel gas supply device 30. A fuel gas (hydrogen-rich gas obtained by reforming a fuel such as hydrogen or methanol) supplied from the fuel gas supply device 30 together with steam. )But,
The fuel gas is supplied to the fuel cell stack 10 through the fuel gas inlet pipe 25. The oxidizing gas inlet pipe 26 is connected to an oxidizing gas supply device 31, and the oxidizing gas (oxygen or air or the like) supplied from the oxidizing gas supply device 31 together with water vapor.
Is connected to the fuel cell stack 1 through the oxidizing gas inlet pipe 26.
0 is supplied. The cooling water inlet pipe 27 is connected to a cooling water supply device (not shown), and the cooling water supplied from the cooling water supply device is supplied to the fuel cell stack 10 through the cooling water inlet pipe 27.

In the fuel cell stack 10, power is generated by an electrochemical reaction between the fuel gas and the oxidizing gas, and the generated power is supplied to a load via a power system device 29.

The fuel gas outlet 14, the oxidizing gas outlet 15, and the cooling water outlet 16 provided at the other end of the fuel cell stack 10 have fuel gas outlet pipe 21, oxidizing gas outlet pipe 22, and cooling water outlet pipe. 24 are connected respectively.

From the fuel gas outlet pipe 21, fuel gas remaining without being used for power generation in the fuel cell stack 10 is discharged together with condensed water and the like. The oxidizing gas remaining without being used for power generation in the fuel cell stack 10 is discharged from the oxidizing gas outlet pipe 22 together with water produced or a condensed water generated by a reaction between the fuel gas and the oxidizing gas. From the cooling water outlet pipe 24, the fuel cell stack 10
The cooling water after cooling is discharged.

For the fuel gas outlet pipe 21 and the oxidizing gas outlet pipe 22, transparent hoses such as Teflon (registered trademark) are used to form a transparent pipe 21a and a transparent pipe 2a.
2a are provided, and an optical sensor 23 is provided in each of these transparent pipe portions 21a and 22a.
The detection signal of the optical sensor 23 is sent to the controller 28.

As shown in FIG. 2, the light sensor 23 includes light emitting elements 23a located on both sides of the transparent pipe portion 21a (22a).
And a light receiving element 23b. The light 33 output from the light emitting element 23a is transmitted through the transparent pipe part 21a (22a), and then received by the light receiving element 23b and photoelectrically converted. As a result, the transparent pipe section 21a and the transparent pipe section 22a
An electric signal corresponding to the degree of transparency of the fluid (fuel gas, oxidizing gas, water) flowing through is obtained.

That is, in the fuel cell stack 10, when the cell 1 is burned out, the fuel gas exhaust hole 14 or the oxidized gas is contained in the fuel electrode or the oxygen electrode constituting the cell 1 because carbon is contained in the component. Carbon (soot) 32 flows out from the gas discharge hole 15, or the fuel gas discharge hole 14 and the oxidizing gas discharge hole 15, and the transparent pipe portion 21a or the transparent pipe portion 22a, or the transparent pipe portion 21a and the transparent pipe portion The transparency of the fluid flowing through 22a decreases. For this reason,
The intensity of the light 33 received by the light receiving element 23b decreases, and the value of the electric signal decreases accordingly.

As shown in FIG. 1, the controller 28 compares the electric signal (transparency of the fluid) received from the optical sensor 23 with a set value, and when the signal becomes equal to or less than the set value, the power system apparatus. 29, fuel gas supply device 30
And a power generation stop signal is sent to the oxidizing gas supply device 31. In the power system device 29, based on the power generation stop signal, the interlock circuit operates to cut off the load. In the fuel gas supply device 30, the interlock circuit operates to stop the supply of the fuel gas based on the power generation stop signal. In the oxidizing gas supply device 31, based on the power generation stop signal, the interlock circuit operates to stop the supply of the oxidizing gas.
Thus, the power generation of the fuel cell stack 10 stops.

As described above, according to the present embodiment, the outflow of carbon at the time of burning of a cell is detected by the optical sensor 23, so that it is immediately recognized that any one of the cells 1 of the fuel cell stack 10 has been burned. can do. Therefore, the other normal cell 1 is abnormally heated (the normal operating temperature is 70 to 80).
℃) to lower the power generation performance, or to cause secondary problems such as fuel gas not being supplied due to a rise in the pressure at the fuel gas outlet side due to the cross leak of the fuel gas and the oxidizing gas. Can be prevented.

In this case, it is desirable to use a high-sensitivity sensor as the optical sensor 23, so that it is possible to detect a small amount of outflow of carbon before a large-scale cell burnout.

In the above description, the case of detecting burnout of a cell in a polymer electrolyte fuel cell stack has been described. However, the present invention is not limited to this case. It can also be applied to the detection of cell burnout in the fuel cell main body.

In the above description, the transparent pipe portions 21a, 22a are provided in a part of the fuel gas outlet pipe 21 and the oxidizing gas outlet pipe 22.
However, the whole fuel gas outlet pipe or the whole oxidizing gas outlet pipe may be a transparent pipe part.

In the above description, the optical sensors 23 are provided on both the fuel gas outlet pipe 21 and the oxidizing gas outlet pipe 22.
Due to the pressure relationship between the fuel gas side and the oxidizing gas side, etc., when carbon flows out from only one of the fuel gas outlet pipe side and the oxidizing gas outlet pipe side during cell combustion, etc. The optical sensor 23 may be provided only on the outlet pipe side or the oxidizing gas outlet pipe side.

[0026]

As described above in detail with the embodiments of the present invention, the cell burnout detecting apparatus according to the first invention comprises a fuel gas outlet pipe, an oxidizing gas outlet pipe, or a fuel gas outlet pipe connected to a fuel cell body. A transparent pipe section is provided in the pipe and the oxidizing gas outlet pipe, and an optical sensor is provided in the transparent pipe section, and a fuel gas outlet pipe or an oxidizing gas outlet pipe or a fuel gas outlet pipe and an oxidizing gas outlet pipe are provided when a fuel cell body is burned. It is configured to detect burning of the cell by detecting, with an optical sensor, a decrease in the transparency of the fluid flowing through the transparent pipe due to carbon discharged from the cell.

A cell burnout detecting apparatus according to a second invention is characterized in that, in the cell burnout detecting apparatus according to the first invention, the fuel cell body is a fuel cell stack formed by stacking a plurality of cells.

Therefore, according to the cell burnout detecting device of the first or second invention, it is possible to immediately recognize that the cells of the fuel cell main body are burnt. In particular, when detecting cell burnout of a fuel cell stack, it is possible to immediately recognize that any one of the cells of the fuel cell stack has burned out, so that other normal cells are abnormally heated and the power generation performance is reduced. It is possible to prevent the occurrence of secondary problems such as a decrease in the fuel gas and an oxidizing gas cross leak, for example, an increase in the pressure on the fuel gas outlet side, whereby the fuel gas is not supplied.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a fuel cell power generation system including a cell burnout detection device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of the cell burnout detection device.

FIG. 3A is a configuration diagram of a cell and a separator, and FIG.
FIG. 2 is a configuration diagram of a fuel cell stack.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 cell 2 electrolyte membrane 3 fuel electrode 4 oxygen electrode 5 separator 6 fuel gas passage 7 oxidizing gas passage 8 cooling water passage 10 fuel cell stack 11 fuel gas introduction hole 12 oxidizing gas introduction hole 13 cooling water introduction hole 14 fuel gas discharge hole 15 Oxidizing gas discharge hole 16 Cooling water discharge hole 17, 18 End plate 21 Fuel gas outlet pipe 21a Transparent pipe part 22 Oxidizing gas outlet pipe 22a Transparent pipe part 23 Optical sensor 23a Light emitting element 23b Light receiving element 24 Cooling water outlet pipe 25 Fuel gas inlet Pipe 26 Oxidizing gas inlet pipe 27 Cooling water inlet pipe 28 Controller 29 Power system device 30 Fuel gas supply device 31 Oxidizing gas supply device 32 Carbon 33 Light

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masatake Ogawa 3000 Tana, Sagamihara-shi, Kanagawa F-term in the General Purpose Machinery & Special Vehicles Division, Mitsubishi Heavy Industries, Ltd. 5H026 AA06 CX06 5H027 AA06 MM03 MM08

Claims (2)

[Claims] 1. A fuel cell, comprising: a fuel gas outlet pipe or an oxidizing gas outlet pipe connected to a fuel cell body; a transparent pipe section provided in the fuel gas outlet pipe and the oxidizing gas outlet pipe; and an optical sensor provided in the transparent pipe section. Detecting with a light sensor that the transparency of the fluid flowing through the transparent pipe portion is reduced by the carbon gas discharged from the fuel gas outlet pipe or the oxidizing gas outlet pipe or the fuel gas outlet pipe and the oxidizing gas outlet pipe when the main body is burned. A cell burnout detecting device configured to detect cell burnout. 2. The cell burnout detection device according to claim 1, wherein the fuel cell body is a fuel cell stack formed by stacking a plurality of cells.