JPS6318303B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a novel stacked fuel cell.

2. Description of the Related Art Conventionally, there is a device shown in FIG. 1 as a stacked fuel cell.

FIG. 1 is a partially cutaway diagram showing the structure of a conventional stacked fuel cell.

In FIG. 1, 1 is a conductive gas separation plate, 2 is a fuel passage, and 3 is an oxidizer passage, which are provided on the upper and lower surfaces of the gas separation plate 1, respectively.
4 is a porous oxidizer electrode, and 5 is a non-conductive porous member impregnated with an electrolyte. A water-repellent treatment is applied to the side where the oxidizer electrode 4 contacts the gas separation plate 1. A gasket 6 is sandwiched between the separation plate 1 and the porous member 5 and surrounds the oxidizer electrode 4. 7 is a fuel electrode, which, like the oxygen electrode, is connected to another gas separation plate 1.
A fuel passage 2 provided in another gas separation plate 1 installed between and a porous member 5
Water-repellent treatment is applied to the side that comes into contact with the Note that the area around the porous member 5 is treated to be air-impermeable.

The air impermeability treatment is a treatment that prevents the gas diffusing the porous member 5 from leaking from the end face.
Usually, a process such as crimping a Teflon (trade name) sheet is performed.

Next, the operation will be explained. The oxidizing agent supplied to the oxidizing agent passage 3 diffuses through the porous oxidizing agent electrode 4, is ionized at the interface with the electrolyte, and reaches the non-conductive porous member 5. Depending on the type of electrolyte, one of the ions moves through the electrolyte solution and reacts with another ion to form a compound. If the fuel is hydrogen, water is produced and current flows in the external circuit. The water generated at this time is discharged from the system together with excess fuel and oxidizer, but some of it dilutes and expands the electrolyte. It has been proposed to provide an electrolyte reservoir (not shown) to temporarily absorb this expansion and restore it to its original state. Expansion and contraction of the electrolyte also occur when the fuel cell is subjected to thermal cycles. Due to these factors, the electrolyte solution impregnated into the porous member 5 is
The gas then passes through the oxidizer electrode 4 and tends to seep out toward the gas separation plate and outward. Therefore, the gas separation plate side of the electrode is treated to be water repellent, and a gasket 6 is provided around the electrode to prevent the electrolyte from seeping out. This gasket 6 also prevents fuel and oxidant from leaking to the outside. Note that leakage outward from the porous member 5 is prevented by air-impermeable treatment applied to the periphery.

Since conventional stacked fuel cells are configured as described above, it is necessary to provide an electrolyte reservoir to prevent the electrolyte from leaking to the outside, and the reservoir is usually located around the outer periphery of the gas separation plate. A non-conductive porous member 5 and a gasket 6 are provided in the
The hole drilled in is connected as a liquid passage. For this reason, there are problems in that the effective area that functions as a battery is reduced in order to secure space for the reservoir, and the structure of the gasket is complicated.

As a result of intensive research to overcome the above-mentioned drawbacks, the inventors of the present invention have developed a non-conductive porous member impregnated with an electrolyte solution, and two electrodes with air permeability and water repellency sandwiching the member. In a stacked fuel cell consisting of a porous member and a gas separation plate that supplies fuel and an oxidizer, an air-impermeable treatment is applied around the porous member and two electrodes, and an impermeable layer on the outermost periphery of the two electrodes is used. A hydrophilic treated part is provided in at least a part of the internal part of the air permeable treated part, and the periphery is surrounded by a gasket between the electrode and the gas separation plate, and a part of the conductive part is partially treated to make it hydrophilic. The present inventors have discovered that by inserting a porous member, a stacked fuel cell can be obtained which simplifies the reservoir structure and eliminates restrictions on manufacturing electrodes and porous members, and has completed the present invention. It was it.

Next, the stacked fuel cell of the present invention will be explained with reference to Examples, but the present invention is not limited thereto.

FIG. 2 is a partially cutaway sketch showing the structure of the stacked fuel cell of the present invention. In FIG. 2, 1 is a gas separation plate, 2 is a fuel passage, 3 is an oxidizer passage, 4 is an oxidizer electrode, 5 is a non-conductive porous member, and 7 is a fuel electrode. 8 is a conductive porous member A inserted between the oxidizer electrode 4 and the gas separation plate 1,
Hydrophilic treatment portions 12 are partially provided so as to locally retain the electrolyte solution, and 9 is a gasket surrounding the porous member A8. 1
Reference numeral 0 denotes a conductive porous member B inserted between the fuel electrode 7 and another gas separation plate 1, which is also partially provided with a hydrophilic treatment section 12, and surrounded by a gasket 9. surrounded by Further, an air-impermeable treatment portion 11 is provided at the outermost periphery of the oxidizer electrode 4 , the non-conductive porous member 5 , and the fuel electrode 7 . A hydrophilic treatment portion 13 is provided in at least a portion of the portion inscribed in the treatment portion 11 .

Next, the operation will be explained. The oxidizing agent supplied to the oxidizing agent passage 3 sequentially diffuses through the conductive porous member A8 and the oxidizing agent electrode 4, is ionized at the interface with the electrolyte, and reaches the non-conductive porous member 5.
On the other hand, the fuel supplied to the fuel passage 2 provided in the other gas separation plate is transferred to the conductive porous member B.
10 and the fuel electrode 7 are sequentially diffused and ionized at the interface with the electrolyte solution, reaching the non-conductive porous member 5. Depending on the type of electrolyte, one type of ion moves through the electrolyte and reacts with another ion to form a compound. If the fuel is hydrogen, water is produced and current is extracted to the external circuit. The electrolyte liquid expands due to the water generated at that time, as in conventional fuel cells, but the expanded electrolyte liquid passes through the hydrophilic part provided around the oxidizer electrode, and in the present invention is absorbed into the conductive porous members A8 and B10. However, the expanded electrolyte solution is prevented from leaking outward from the oxidizer electrode 4, the non-conductive porous member 5, and the fuel electrode 7 by the air-impermeable treatment portion 11 applied to the outermost periphery of these electrodes. ing. The gasket 9 prevents the oxidant and fuel from leaking between these components to the outside, other than by diffusing through the porous member and the electrodes. Conductive porous member A8, B1
0 has been partially hydrophilic treated, so
The electrolyte liquid absorbed by these porous members is absorbed by the hydrophilic portion, and does not impede the diffusion and passage of the fuel and oxidizer supplied from the gas separation plate.

In the above example, the conductive porous members A8 and B10 were partially subjected to hydrophilic treatment, but the conductive porous members were made hydrophilic by locally changing the pore size distribution. You may provide a portion.

As described above, according to the stacked fuel cell of the present invention, by inserting the conductive porous member between the gas separation plate and the electrode, the expansion of the electrolyte caused by the operation of the fuel cell is made conductive. It can be absorbed into the porous member, further improving the reliability of the stacked fuel cell.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway sketch showing the structure of a conventional stacked fuel cell, and FIG. 2 is a partially cutaway sketch showing the structure of the stacked fuel cell of the present invention. (Numbers in the drawing), 1: Gas separation plate, 2: Fuel passage, 3: Oxidizer passage, 4: Oxidizer electrode, 5: Non-conductive porous member, 6, 9: Gasket, 7: Fuel electrode, 8 : Conductive porous member A, 10: Conductive porous member B, 11: Air-impermeable treated portion, 12, 13:
Hydrophilic treatment section.

Claims (1)

[Claims] 1. A non-conductive porous member impregnated with an electrolyte solution, and 2.
In a stacked fuel cell consisting of two electrodes and a gas separation plate that supplies fuel and oxidizer to the electrodes,
Air-impermeable treatment is applied to the periphery of the porous member and the two electrodes, and a hydrophilic-treated portion is provided on at least a portion of the portion inscribed in the air-impermeable treatment portion on the outermost periphery of the two electrodes, and A stacked fuel cell characterized in that a conductive porous member surrounded by a gasket and partially subjected to hydrophilic treatment is inserted between an electrode and a gas separation plate.