JPH10270065A - Solid polymer electrolyte fuel cell, cell unit and fuel supply method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To purge a fuel chamber with circulation water for preheating a cell when starting a solid polymer electrolyte fuel cell. SOLUTION: The outlet sides of a fuel chamber and a circulation water chamber, communicating each other, are connected to a circulation water device 6 via a discharge valve 65 and the inlet side of the fuel chamber is connected to a fuel source via a fuel supply valve 57 and to the circulation water device 6 via a return valve 56. A fuel plate constituting a cell unit has a fuel chamber on the anode side of a cell 2 and a circulation water chamber on the other surface and an oxidant plate 4 has an oxidant chamber on the cathode side of the cell and a circulation water chamber on the other surface, both circulation water chambers being communicated with a common communication discharge port 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid polymer electrolyte fuel cell, an improved cell unit, and a fuel supply method.

[0002]

2. Description of the Related Art As shown in FIGS. 2 and 3, a solid polymer electrolyte fuel cell is ion-conductive and has an anode on one surface of a solid polymer electrolyte membrane (21) for transferring protons.
(22) A fuel plate having a fuel chamber (31) on the anode side with respect to a cell (2) having a cathode (23) on the other surface.
(3) On the cathode side, an oxidant plate (4) having an oxidant chamber (41) is arranged, and a fuel plate (3) is provided before and after the cell (2).
And an oxidant plate (4) sandwiching the same. A circulating water chamber (35) (45) through which circulating water flows is formed on the back surface of the fuel plate and the oxidant plate, and a set of these three (2) (3) (4) They are bundled and unitized. A hydrogen-rich fuel formed by reforming methane gas, city gas, etc. is supplied to each fuel chamber (31) of the fuel cell unit, and, for example, air is circulated as an oxidant to the oxidant chamber (41). Let it.

At the anode (22) of the cell (2), hydrogen supplied from outside the system is

(Equation 1) Produces protons and electrons. Cathode (2
In (3), oxygen supplied from outside the system as an oxidizing agent, protons moved through the solid polymer electrolyte membrane (21), and electrons flowing from an external circuit are generated.

(Equation 2) The reaction produces water.

[0004]

[Problems to be solved] Solid polymer electrolyte fuel cells
Depending on the capacity and application, it can be performed several times a day or several times a week,
Stop and start operations are performed. At the time of startup, if air is mixed into the fuel chamber for some reason, it will cause a rapid reaction with hydrogen as fuel, and it is dangerous.
The fuel chamber is previously filled with an inert gas, and a purge is performed to remove residual gas in the fuel chamber. Thereafter, the fuel gas is supplied and normal operation is performed. Therefore, in the solid polymer electrolyte fuel cell, an inert gas cylinder for purging must be installed, and there is a problem that the equipment becomes large.

Further, since the electrochemical reaction rate in the cell plate depends on the temperature, the cell is preheated to a temperature suitable for the reaction, for example, 80 to 100.degree. There is a need. conventionally,
The circulating water was operated with warm water of about 80 ° C, and the circulating water chamber of the cell was circulated and preheated, but the circulating water chambers (35) and (45) were isolated from the cell (2), and the fuel plate (3) Since the heating is indirect through the oxidant plate (4), the efficiency is low.

According to the present invention, when the fuel cell is started, the fuel chamber is purged with the circulating water and the cell is preheated to the operating temperature by switching the circulating water passage so as to pass through the fuel chamber.

[0007]

In the present invention, the fuel chamber (31) and the outlet side of the circulating water chamber (35) (45) communicate with each other, and are connected to the circulating water device (6) via a discharge valve (65) to provide the fuel chamber ( The inlet side of (31) is connected to a fuel source via a bypass valve (54) and a fuel supply valve (57), and is connected to a circulating water device (6) via a return valve (56). is there. The fuel plate that constitutes the cell unit
On the anode side of (2), the fuel chamber (31), on the other surface,
The oxidizing plate (4) has a circulating water chamber (35) on the cathode side of the cell and a circulating water chamber (45) on the other surface. And each circulating water chamber (35) (4
5) is formed by communicating with a common communication outlet (14).

[0008]

[Function] When the fuel cell is started, the discharge valve of the circulating water device (6)
(65) and the bypass valve (54) of the fuel supply device (5) are closed, and the return valve (56) is opened. Before feeding the fuel and the oxidizer, the circulating water is supplied to the circulating water chamber (35) (4) by the circulating water device (6).
5) to fill the circulating water chambers (35) and (45). Since the discharge valve (65) on the circulating water outflow pipe (64) is closed, the circulating water flows into the fuel chamber (31) and purges the fuel chamber. The circulating water overflowing from the fuel chamber flows back through the fuel supply device, but since the fuel supply valve (57) and the bypass valve (54) are closed,
After returning to the circulating water device (6) via the return valve (56), the above-mentioned circulation is repeated.

The cell has finished purging with circulating water,
And when preheated to the operable temperature, the discharge valve (65) opens,
In the fuel humidifier (52), the fuel supply valve (57) opens, and the return valve (56) closes. Accordingly, the circulating water that has passed through the circulating water chambers (35) and (45) merges at the communication discharge port (14), and returns to the circulating water device via the discharge valve (65) and the circulating water outflow pipe (64).
In the fuel humidifier, the fuel supply valve (57)
Fuel is directly supplied to each fuel chamber (31), and the circulating water that has filled the fuel chamber is pushed down. The fuel chamber (31) is filled with fuel gas, and normal operation starts.

[0010]

When the fuel cell is started, circulating water is used to purge the fuel chamber. Therefore, it is only necessary to switch the valves of the fuel supply device and the circulating water device. As in the conventional case, a special inert gas cylinder is used for purging. No need to install. Also,
Since the circulating water flows into the fuel chamber to directly heat the cell, high preheating efficiency can be obtained.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS The drawings and description which follow illustrate one embodiment of the present invention and should not be used to limit the scope of the claims. Fuel cell (1) consists of cell (2), fuel plate (3) and oxidizer plate
It comprises a cell unit in which 10 to 20 sets of (4) are bundled. As shown in FIGS. 2 and 3, the cell unit has a fuel supply port (1) at the same position above (2), (3) and (4).
1), circulating water supply port (12) and oxidant supply port (14). At the same position under each of (2), (3) and (4), a horizontally long communication discharge port (14) and an oxidizing agent discharge port (15) are opened. When a plurality of sets sandwiching the cell (2) by the fuel plate (3) and the oxidant plate (4) are bundled, a surface facing the same direction, for example, a surface facing the right side is a surface A, and a surface facing the left side is a surface B. Then, the supply ports (11), (12), (13) and the discharge ports (14), (15) coincide with each other on the same line. Fuel plate (3)
A fuel chamber (31), which is slightly shallower than half of the plate thickness, is recessed in the center on the surface (surface B) that contacts the anode (22) of the cell, and the fuel chamber (31) is provided with a fuel inflow passage (33). ) Communicates with the fuel supply port (11), and communicates with the communication discharge port (14) through the fuel outflow path (34). On the bottom of the fuel chamber (31), a plurality of vertical ribs (32) are located at positions away from the upper and lower sides of the fuel chamber.
Are juxtaposed. A circulating water chamber (35) is formed in the center of the back surface (A surface) of the fuel plate (3) and communicates with the circulating water supply port (12) through a circulating water inflow passage (37). And a circulating water chamber
The lower part of (35) passes through the circulation outflow channel (38) and the communication outlet (14).
Leading to

An oxidizing agent chamber (41) having a vertical rib (42) is recessed on the side (surface A) of the oxidizing agent plate (4) in contact with the cell (2). The upper part communicates with the oxidant supply port (13) through the oxidant supply path (43), and the lower part is the oxidant discharge path.
Through (44), it communicates with the oxidant outlet (15). The back surface (surface B) of the oxidant plate (4) has the same shape as the back surface (surface A) of the fuel plate (3) with a circulating water chamber (45) with a rib (46) and an inflow passage (47) for oxidant, It has an outflow channel (48).

Each of the above-mentioned (2), (3) and (4) is formed by aligning the required number of sets in the same direction and tightly tightening them so that each fuel chamber (31)
Communicates with the common fuel supply port (11) and the communication discharge port (15). The oxidant chamber (41) communicates with a common supply port (13) and discharge port (15). Circulating water chambers (35) and (45) have a common supply port
(12) and the outlet (14).

FIG. 2 is a longitudinal sectional view of the cell unit. For convenience of explanation, the fuel supply port (14), the circulation port (14), and the circulating water (12) are drawn with their positions shifted up and down. ing. The oxidant supply port and the oxidant discharge port are omitted.

The fuel cell (1) includes a fuel port (16), a circulating water port (17), an oxidizer port (18), and a communication discharge port (19). The circulating water supply port (12), the oxidant supply port (13), and the communication discharge port (14) are connected. The circulating water device (6) connects the circulating water supply pipe (6) from the outlet of the water tank (66) to the circulating water port (17) via the pump (62) and the heat exchanger (63), and , A discharge tank (64) having a discharge valve (65) and a water tank communicating with a discharge port (19)
(66) is connected to the upper part.

The fuel humidifier (5) discharges the hydrogen-rich fuel gas sent from the fuel supply device into the water of the fuel humidifier (52), raises the humidity of the fuel gas, and supplies the fuel to the outlet. The pipe (51) is connected to the fuel port (16) of the fuel cell (1). Between the fuel supply pipe (51) and the humidifier (52),
A tub is connected by a bypass pipe (53) having a bypass valve (54), and the bottom of the humidifier (52) is connected to a water tank (66) of the circulating water device (6) by a return pipe (55) having a return valve (56). ). The circulating water is reduced to about 80 by the heat exchanger (63).
The temperature is maintained at ℃, and the cell unit of the fuel cell (1) is maintained at an appropriate temperature.

When starting up the fuel cell, first, before supplying the fuel gas and the oxidizing agent, first, the discharge valve (65) and the fuel supply valve (5) are supplied.
7) Close the bypass valve (54) and open the return valve (56). Since the circulating water path of the circulating water device (6) is stopped by the discharge valve (65), the circulating water does not flow out to the discharge pipe (65), but each of the circulating water flows through the common discharge port (14). Fuel chamber (31), fuel supply pipe (5
1) Form a circulation path returning to the water tank (66) via the humidifier (52) and the return pipe (55). Therefore, the circulating water that has passed through the circulating water chambers (34) and (45) flows into the fuel water chamber (31), pushes up residual gas, flows back through the fuel supply pipe (51), and flows into the water tank (66). A return cycle is performed. Since the fuel chamber (31) is in direct contact with the cell (2), the preheating of the cell (2) by the circulating water is performed efficiently.

When the temperature of the cell (2) reaches a suitable temperature, the four valves are switched manually or automatically, and the circulating water device closes the passage including the return pipe (55). A passage including the discharge pipe (64) is formed, and the circulating water fills the circulating water chamber (35) (45), and then flows out of the communication discharge port (14).
After (64), return to the water tank (66). Fuel supply device (5)
The fuel supply valve (57) is opened, and the fuel pushes down the circulating water in the fuel chamber (31) through the fuel supply pipe (51), and the communication discharge port (1
In 4), it is mixed with circulating water,
(66). The circulating water returned to the water tank (66) is sent to the circulating water supply pipe (61) again by the pump (62). The unreacted residual fuel gas separated in the water tank (66) is used as combustion gas in the reformer.

[0019]

[Other embodiments] By connecting the oxidizing agent chamber (41) of the oxidizing agent plate (4) with the circulating water chamber (45), the fuel cell can
The circulating water flows from the circulating water chamber (45) to the oxidizing chamber (41),
The oxidant chamber (41) may be directly heated. Start the fuel chamber (3
The circulating water purged from 1) does not necessarily need to be returned to the circulating water device (6) via the return pipe (55) and the return valve (56).
If the capacity of the heat exchanger (63) is large, water may be supplied from the outside. The present invention is not limited to the above embodiments, and it is obvious that those skilled in the art can make many modifications based on the drawings and the above description.

[Brief description of the drawings]

[Figure 1] Fuel cell (1), fuel humidifier (5), circulating water chamber (6)
FIG. 3 is an overall explanatory diagram showing the arrangement of the holograms.

FIG. 2 is a longitudinal sectional view of a cell unit, showing a fuel supply port;
The position of (11) is shifted, and the oxidant supply port is omitted.

FIG. 3 shows a cell constituting a cell unit, a fuel plate,
FIG. 4 is an oblique view showing the oxidant plate separately.

FIG. 4 is a front view and a rear view of a cell, a fuel plate, and an oxidant plate, in which a side facing one direction is a surface A and a side facing the other direction is a surface B.

[Explanation of symbols]

 (1) Fuel cell (11) Fuel supply port (12) Circulating water supply port (13) Oxidant supply port (14) Communication outlet (15) Oxidizer outlet (2) Cell (21) Solid polymer electrolyte membrane (22) Anode (23) Cathode (3) Fuel plate (31) Fuel chamber (35) Circulating water chamber (4) Oxidizer plate (41) Oxidant chamber (45) Circulating water chamber (5) Fuel supply device (51) ) Fuel supply pipe (53) Bypass pipe (54) Bypass valve (55) Return pipe (56) Return valve (57) Fuel supply valve (6) Circulating water device (61) Circulating water supply pipe (64) Circulating water outlet pipe (65) Discharge valve

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Koji Nishio 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd.

Claims (4)

[Claims] 1. A cell (2) having an anode (22) formed on one surface of a solid polymer electrolyte membrane (21) and a cathode (23) formed on the other surface of the solid polymer electrolyte membrane (21). The oxidizing agent chamber (41) that circulates, and the fuel chamber (31) that circulates fuel to the anode (22) side
Circulating water chamber (35) (45)
In the fuel cell for adjusting the temperature of the cell (2), the fuel cell (31) and the circulating water chambers (35) and (45) communicate with the respective outflow sides, A solid polymer electrolyte fuel cell connected to a discharge valve (65), and an inflow side of the fuel chamber (31) connected to a fuel source via a fuel supply valve (57). 2. A cell (2) in which an anode (22) is formed on one surface of a solid polymer electrolyte membrane (21) and a cathode (23) is formed on the other surface of the solid polymer electrolyte membrane (21). ) Side, the fuel chamber on one surface
(31), a fuel plate having a circulating water chamber (35) on the other surface
On the cathode (23) side of the cell (2), an oxidant plate (4) having an oxidant chamber (41) on one surface and a circulating water chamber (45) on the other surface is disposed. Place the fuel chamber in the fuel plate (3)
(31), and the circulating water chambers (35) and (45) of the fuel plate (3) and the oxidant plate (4) communicate with the common communication outlet (14). Cell unit. 3. A cell plate (2) having an anode (22) formed on one surface of a solid polymer electrolyte membrane (21) and a cathode (23) formed on the other surface, and an oxidizing agent placed on the cathode (23) side. The oxidizing chamber (41) through which the fuel gas flows through the anode (22) is disposed, and the circulating water chamber (35) (45) through which the circulating water flows is disposed in the cell (2). In the fuel cell that is installed close to the cell and controls the temperature of the cell (2), at the time of startup, before the fuel and oxidant are supplied, the circulating water device (6)
The circulating water is sent to the circulating water chamber (35) by the
The circulating water passing through the fuel chamber (31) flows into the fuel chamber (3).
1), the anode (22) is preheated, and during normal operation, the circulating water that has passed through the circulating water chamber (35) is directly returned to the circulating water device (6), and fuel and oxidant are sent. A fuel supply method for a solid polymer electrolyte fuel cell, characterized in that circulating water in the fuel chamber (31) is pushed out and fuel is circulated through the fuel chamber (31). When starting, the circulating water that has passed through the circulating water chamber (35) flows into the fuel chamber (31) and also into the oxidant chamber (41) to preheat the cathode (23), During normal operation, the oxidant pushes out the circulating water in the oxidant chamber (41) and
4. The fuel supply method for a solid polymer electrolyte fuel cell according to claim 3, wherein the oxidant is passed through 1).