JPS6338533Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a matrix fuel cell that generates electricity by receiving a fuel gas such as hydrogen gas and an oxidizing gas such as air. The present invention also relates to a device for preventing the generation of differential pressure between electrodes when sealed and stored in an oxidizer chamber.

Generally, the space between the fuel chamber and the oxidizer chamber in this type of fuel cell is formed from a relatively thin electrode base material and an electrolyte-impregnated matrix, so that it cannot be expected to have much strength against the differential pressure between the two chambers. The easiest way to solve this problem is to open the exhaust sides of both chambers to the atmosphere and maintain the same pressure, but when filling with inert gas when the fuel cell is stopped, it is necessary to keep them sealed. Therefore, this method cannot be adopted.

Furthermore, if the equipment is simply filled with inert gas and sealed, not only will differential pressure be generated during the cooling process depending on the temperature and pressure conditions at the time of shutdown, but there will also be a risk of damage to the equipment due to negative pressure during cooling.

Therefore, an object of the present invention is to provide a device that can keep the differential pressure between both chambers within a certain range without being affected by the length of the rest period of the matrix fuel cell or the surrounding atmospheric conditions.

According to the present invention, this purpose is to measure the differential pressure between the fuel chamber and the oxidizer chamber of the fuel cell and the pressure in at least one of the two chambers, and, based on the measurement results, to control the pressure in each chamber. This is achieved by controlling the valves that control the supply or discharge of active gas. Specifically, the second part supplies inert gas to the fuel chamber of the fuel cell.
a third valve for discharging inert gas from the fuel chamber.
a first valve for supplying inert gas to the oxidizer chamber of the fuel cell, a fourth valve for discharging inert gas from the oxidizer chamber, and a valve between the fuel chamber and the oxidizer chamber. A pressure measuring device that detects a differential pressure and a pressure measuring device that measures the pressure in a fuel chamber or an oxidizer chamber, and controls a first (or second) valve based on the output of the pressure measuring device. , a second or third valve (first or fourth valve) is controlled based on the output of the differential pressure measuring device so that the differential pressure between the fuel chamber and the oxidizer chamber is below a predetermined value. do.

Next, the configuration and operation of an embodiment of the present invention will be explained based on the drawings.

In FIG. 1, a fuel cell 1 includes a fuel chamber 2, a fuel electrode 3, a matrix 4, and an oxidizer (air) electrode 5.
and an oxidizer (air) chamber 6. Fuel gas such as hydrogen gas is supplied to the fuel chamber 2 from a fuel processing device (not shown) via an inlet valve 7 and an outlet valve 8.
is discharged through. Air as oxidant gas is fed into the air chamber 6 via the inlet valve 9 and discharged via the outlet valve 10. Normally, the power generation action of the fuel cell is performed by a known reaction by the catalyst of the electrode by supplying such fuel gas and oxidant gas.

When stopping or resting the fuel cell, close valve 7.
~10 is closed and inert gas e.g. nitrogen gas
N ₂ is supplied to the fuel chamber 2 via the second valve (inert gas supply valve) 11 . The gas that has been present in the fuel chamber 2 and the nitrogen gas that is continuously supplied until the replacement is completed are discharged via the third valve 12 (inert gas discharge valve). At the same time, a first valve 13 (inert gas supply valve) and a fourth valve are installed on the air chamber side.
Nitrogen gas is supplied through the valve (inert gas discharge valve) 14.

When the replacement with nitrogen gas is completed, it is recommended to leave the first to fourth valves 13, 11, 12, and 14 fully closed to avoid thermal shock to the fuel cell, which was at a high temperature until then. As the temperature of the nitrogen gas, which had been preheated in may threaten the mechanical strength of the

In phosphoric acid fuel cells, air is generally used as the oxidizing agent, and this air is supplied to the battery in a larger amount than the fuel gas, so the manifolds and piping equipment that make up the battery become larger on the air side. Naturally, the heat capacity will be different between the two gas chambers. For this reason, if the gas chamber is sealed with an inert gas when the battery is at rest, the pressure inside the chamber decreases as the temperature decreases, creating a pressure difference between the fuel chamber side and the air chamber side. To prevent this, there is a method of continuing to flow inert gas into the room during shutdown, but this leads to evaporation of the electrolytic chamber held in the matrix and also consumes a large amount of inert gas, which is not economical.

Therefore, according to the present invention, the pressure in the air chamber 6 is measured by the pressure measuring device P, the first valve 13 is controlled so that the air chamber pressure maintains a predetermined value, and the pressure difference between the two chambers is controlled on the other hand. The second valve 11 or the third valve 1 is operated so that the differential pressure measured by the differential pressure measuring device ΔP is equal to or less than a predetermined value.
2, the differential pressure between the two chambers is maintained at a predetermined value or less.

It is obvious that the same effect can be obtained in the above control even if the relationship between the fuel chamber and the air chamber is reversed.

Also, depending on the allowable differential pressure, a pressure measuring device may be installed in the other chamber instead of the differential pressure measuring device ΔP, and the differential pressure can be effectively measured from the difference in output between the two pressure measuring devices. You may also do so.

Thus, according to the present invention, it is possible to stop the matrix-type fuel cell in a state where the inside thereof is isolated from the atmosphere, and it is possible to obtain the effect of extending the performance retention period of the fuel cell. Furthermore, compared to the case where inert gas is continued to flow during rest, evaporation of the battery electrolyte can be prevented and the amount of inert gas consumed can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of main parts of an embodiment of the present invention. 1 ... Fuel cell, 2... Fuel chamber, 6... Air chamber, 11, 13... Inert gas supply valve, 12, 1
4...Inert gas discharge valve, P...Pressure measuring device,
ΔP……Differential pressure measuring device.

Claims (1)

[Scope of utility model registration request] A first control valve that controls the amount of inert gas supplied to one of the chambers based on the pressure of one of the chambers, in which the fuel chamber and the oxidizer chamber are sealed with inert gas when the matrix fuel cell is stopped; A second control unit that controls the amount of inert gas supplied to the other chamber or the amount of inert gas discharged from the other chamber based on the differential pressure between the two chambers.
or a third control valve.