JP3297125B2 - Shutdown storage method of solid polymer electrolyte fuel cell - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for storing a solid polymer electrolyte fuel cell when operation is stopped.

[0002]

2. Description of the Related Art The general principle of power generation in a solid polymer electrolyte fuel cell will be described below with reference to FIG.

As shown in FIG. 3, the solid polymer electrolyte fuel cell comprises an electrolyte 1 comprising a polymer ion exchange membrane such as a fluororesin ion exchange membrane having a sulfonic acid group.
The structure has a battery body 6 composed of catalyst electrodes 2, 3 made of, for example, platinum and porous carbon electrodes 4, 5 arranged on both sides of the electrolyte 1.

In the fuel cell having such a structure, hydrogen in the fuel supplied to the anode is hydrogen-ionized on the catalyst electrode (anode) 2 as shown in the following formula (1), Is H ^{+ with} the presence of water in the electrolyte 1. Move to the cathode 3 side as xH ₂ O. On the catalyst electrode (cathode electrode) 3, as shown in the following formula (2), it reacts with oxygen in the oxidizing agent and electrons flowing through the external circuit 7 to generate water, and is discharged to the outside of the fuel cell. At this time, the flow of electrons flowing through the external circuit 7 is used as DC electric energy. (Anode side) H ₂ → 2H ⁺ + 2e ^- … (1) (Cathode side) 1/2 O ₂ + 2H ⁺ + 2e ^- → H ₂ O ... (2) (all reactions) H ₂ +1/2 O ₂ → H ₂ O

In order for the ion-exchange membrane serving as the electrolyte 1 to have the above-described ion permeability, it is necessary that the membrane be constantly maintained in a sufficiently water-retaining state. Therefore, conventionally, the fuel or the oxidant is supplied to the fuel cell after being humidified. When the operation of the fuel cell is stopped, the anode electrode side and the cathode electrode side are subjected to a purging process using a dry inert gas, and are stopped and stored. Therefore, the ion exchange membrane temporarily returns to a dry state. Therefore, when the fuel cell restarts,
The method of returning the ion exchange membrane to the water-retaining state again by the humidified inert gas or the like, then supplying the fuel and the oxidant, and starting the re-generation is adopted.

[0006]

In the conventional method of stopping and storing the solid polymer electrolyte fuel cell, the ion exchange membrane is once returned to a dry state. Therefore, (1) humidified inert gas or the like upon restarting Therefore, it takes time to return the ion exchange membrane to the water retention state again. (2) Since the humidified inert gas or the like is supplied at the time of restart, the amount of the inert gas used increases accordingly. There was a problem.

An object of the present invention is to provide a solid polymer electrolyte fuel cell capable of promptly starting power generation by introducing a fuel and an oxidizing agent at the time of restart and reducing the amount of inert gas used. To provide a suspension storage method.

[0008]

According to the present invention, there is provided a method for stopping and storing a solid polymer electrolyte fuel cell, wherein a humidified inert gas is sealed in a fuel gas passage or an oxidizing gas passage of a cell body. A method for stopping and storing a solid polymer electrolyte fuel cell, comprising stopping operation and storing.

[0009]

According to the present invention, when shutting down the operation of the ion exchange membrane which is the electrolyte of the solid polymer electrolyte fuel cell, the humidified inert gas is caused to flow through the fuel gas flow path or the oxidizing gas flow path. In addition, it becomes possible to purge the battery while keeping the ion exchange membrane in a water-retaining state. Also,
By enclosing the humidified inert gas as it is, it is possible to store the ion exchange membrane in a water-retaining state until restarting. Therefore, at the time of restart, power generation can be promptly started by introducing the fuel and the oxidant.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. Example 1

FIG. 1 is a schematic diagram showing a solid polymer electrolyte fuel cell system used in the first embodiment. The fuel supply device 11 is connected to the anode 1 through the fuel-side humidifier 12.
3 is connected. The oxidant supply device 14 is connected to the cathode 16 through an oxidant-side humidifier 15.
The electrolyte 17 composed of an ion-exchange membrane is
3 and the cathode 16. The inert gas supply device 18 is connected to the pipe between the fuel supply device 11 and the fuel-side humidifier 12 and the pipe between the oxidant supply device 14 and the oxidant-side humidifier 15 via a pipe. I have.

The two first gate valves 19a and 19b are interposed in piping downstream of the fuel supply device 11 and the oxidant supply device 14, respectively. The two second gate valves 20a and 20b are interposed in piping downstream of the fuel-side humidifier 12 and the oxidant-side humidifier 15, respectively. The two third gate valves 21 a and 21 b are interposed in piping downstream of the anode 13 and the cathode 16, respectively. Two fourth gate valves 22a, 22b
Are interposed in the pipes near the inert gas supply device 18, respectively. Next, a method for stopping and storing the solid polymer electrolyte fuel cell according to the first embodiment will be described with reference to the system shown in FIG.

First, the fourth gate valves 22a and 22b are closed, and the fuel is supplied from the fuel supply device 11 to the anode 13 through the fuel-side humidifier 12, and the oxidant is supplied to the oxidant supply device 1.
4 to the cathode 16 via the oxidant-side humidifier 15 to generate power.

When the operation of the fuel cell is stopped, the supply of fuel from the fuel supply device 11 is stopped, and instead, the fourth gate valve 22a is opened and inert gas is supplied from the inert gas supply device 18 to the fuel cell. The side humidifier 12 is supplied, and the humidified inert gas is supplied to the anode 13 to purge the fuel remaining in the anode 13 and replace the inert gas with the inert gas. After completing the replacement, the second on the fuel pipe side,
Closing the third gate valve 20a, 21a or the first,
The closing of the humidified inert gas is completed by closing the third gate valves 19a and 21a.

Further, the supply of the oxidizing agent from the oxidizing agent supply device 14 is stopped, and instead, the fourth gate valve 22b is opened and the inert gas is supplied from the inert gas supplying device 18 to the oxidizing agent humidifier 15. The humidified inert gas is supplied to the cathode 16 to replace the inert gas while purging the oxidant remaining in the cathode 16. After completion of the replacement, the second and third gate valves 20 on the oxidant piping side
b, 21b is closed or the first and third gate valves 19 are closed.
By closing b and 21b, the filling of the humidified inert gas is completed.

According to the first embodiment, the operation is stopped and stored in a state where the humidified inert gas is sealed in the fuel gas flow path or the oxidizing gas flow path, whereby the ion exchange of the electrolyte 17 is performed. Since the water retention state can be maintained without drying the membrane, at the time of restart, power generation can be started immediately by introducing fuel and oxidant from the fuel supply device 11 and the oxidant supply device 14, respectively. . Example 2

Reference Example 1 FIG. 2 is a schematic diagram showing a solid polymer electrolyte fuel cell system used in Reference Example 1 . Fuel supply device 31
Is connected to the anode 33 through the fuel-side humidifier 32. The oxidizer supply device 34 includes an oxidizer-side humidifier 35.
Through to the cathode 36. An electrolyte 37 made of an ion exchange membrane is interposed between the anode 33 and the cathode 36. Water supply device 38
Is between the fuel humidifier 32 and the anode 33,
And it is connected to the pipe between the oxidant-side humidifier 35 and the cathode 36 via a pipe.

The two first gate valves 39a and 39b are interposed in pipes downstream of the fuel supply device 31 and the oxidant supply device 34, respectively. The two second gate valves 40a and 40b are interposed in piping downstream of the fuel-side humidifier 32 and the oxidant-side humidifier 35, respectively. The two third gate valves 41a and 41b are interposed in pipes on the upstream side of the anode 33 and the cathode 36, respectively. The two pipes connected to the water supply device 38 are connected to pipes between the second gate valves 40a, 40b and the third gate valves 41a, 41b, respectively. The two fourth gate valves 42a and 42b are
The anode electrode 33 and the cathode electrode 36 are interposed in downstream pipes, respectively. Two fifth gate valves 4
3a and 43b are interposed in the pipe near the water supply device 31, respectively. Next, a method for stopping and storing the solid polymer electrolyte fuel cell of Reference Example 1 will be described with reference to the above-described system of FIG.

First, the fifth gate valves 43a and 43b are closed, and the fuel is supplied from the fuel supply device 31 to the anode 33 through the fuel side humidifier 32, and the oxidant is supplied to the oxidant supply device 3.
4 to the cathode 36 through the oxidant-side humidifier 35 to generate power.

When the operation of the fuel cell is stopped, the supply of fuel from the fuel supply device 31 is stopped, and instead, the second gate valve 40a is closed, and the fifth gate valve 43a is opened to discharge water. The fuel is supplied from the supply device 38 to the anode 33, and the fuel remaining in the anode 33 is purged and replaced with water. After the replacement is completed, the third and fourth gate valves 41a and 42a on the fuel pipe side are closed to complete the filling of the water.

Further, the supply of the oxidizing agent from the oxidizing agent supply unit 34 is stopped, and instead, the second gate valve 40b is closed, and the fifth gate valve 43b is opened to supply water from the water supply unit 38 to the cathode. replacing the water while purging residual oxidizing agent of the cathode electrode 3 6 is supplied to the electrode 36. After completion of the replacement, the third and fourth gate valves 41b and 4
The closing of water is completed by closing 2b.

[0022]

[0023]

[0024]

As described in detail above, according to the method for stopping and storing the solid polymer electrolyte fuel cell according to the present invention, the operation of the ion exchange membrane, which is the electrolyte of the solid polymer electrolyte fuel cell, is stopped, and water is always retained during storage. (1) Power generation can be started promptly by introducing fuel and oxidant when the fuel cell is restarted.

(2) It is possible to omit the operation of returning the ion exchange membrane to a water-retaining state by using a humidified inert gas or the like at the time of restart, and to reduce the amount of the inert gas used. Has a remarkable effect.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a solid polymer electrolyte fuel cell system according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a system of a solid polymer electrolyte fuel cell in Reference Example 1 .

FIG. 3 is a schematic view showing the principle of power generation of a solid polymer electrolyte fuel cell.

[Explanation of symbols]

11: fuel supply device, 12, 15: humidifier, 13: anode electrode, 14: oxidant supply device, 16: cathode electrode, 1
7 ... electrolyte, 18 ... inert gas supply device.

Claims (1)

(57) [Claims] In a method for stopping and storing a solid polymer electrolyte fuel cell, the operation is stopped and stored with a humidified inert gas sealed in a fuel gas flow path or an oxidizing gas flow path of a cell body. A method for stopping and storing a solid polymer electrolyte fuel cell.