JPH0622146B2 - Fuel cell - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fuel cell, and more particularly to a fuel cell having a novel seal structure.

[Conventional technology]

FIG. 5 is a perspective view showing the inside by partially cutting away the conventional fuel cell disclosed in, for example, Japanese Patent Laid-Open No. 59-56366, in which (1) is a separator plate and (2) is this separator plate. (1) a fuel channel provided on the front surface, (3) a back surface of the separator plate (1), an air channel provided orthogonal to the fuel channel (2), (4) a separator plate ( Fuel electrode provided adjacent to the surface of (1), (5) is a fuel gasket provided on the separator plate (1) surrounding the periphery of this fuel electrode (4), and (6) is these fuel electrodes. (4) and the matrix provided on the fuel electrode gasket (5), (7) is the air electrode provided on this matrix (6), and (8) is the matrix surrounding the periphery of the air electrode (7).
(6) The air electrode gasket provided above. The air electrode (7) and the air electrode gasket (8) are also adjacent to the back surface of the separator plate (1). Therefore, these fuel poles
The (4), the matrix (6), and the air electrode (7) are sandwiched and laminated between the two separator plates (1).

The conventional fuel cell is configured as described above, and the separator plate
The fuel gas and air separated in (1) are supplied to the fuel flow path (2) and air flow path (3), and the fuel electrode (4) and air electrode are
Each is ionized at (7). Ions generated in the fuel electrode (4) or the air electrode (7) move in the matrix (6) holding the ionic conductive electrolyte and are carried to the other electrode, thereby obtaining an electric output. To be The fuel electrode gasket (5) and the air electrode gasket (8) are provided to prevent the fuel gas in the fuel channel (2) and the air in the air channel (3) from leaking to the outside. .

[Problems to be solved by the invention]

In the conventional fuel cell as described above, the fuel electrode (4) and the fuel electrode gasket (5) or the air electrode (7) and the air electrode gasket are used.
It is difficult to make the thickness of (8) uniform, and since the elastic constants of these electrodes and gaskets are different, even if the thickness can be made uniform, two separator plates (1) If the fuel electrode (4), air electrode (7), and matrix (6) are sandwiched between the two parts, the applied surface pressure will differ between the part with the gasket and the part without the gasket, resulting in insufficient sealing or contact. There was a problem such as an increase in resistance. In addition, a gap is unavoidable between the fuel electrode (4) and the air electrode (7) and their respective gaskets, so gas and electrolyte leakage may occur through the gap. There was a point. Further, in a fuel cell using a phosphoric acid electrolyte at high temperature, during long-term use of the fuel cell,
There has been a problem that the fuel electrode gasket (5) and the air electrode gasket (8) are eroded and it is difficult to keep the sealing property of the reaction gas and the electrolytic solution for a long period of time.

The present invention has been made to solve the above problems, and there is no step or gap other than the seal portion and the seal portion, uniform surface pressure can be applied, and it is also resistant to corrosion by the electrolytic solution at high temperature. The purpose is to obtain a fuel cell having a seal structure.

[Means for solving problems]

The fuel cell according to the present invention has a fuel electrode and an air electrode expanded to the same size as the outer shape of the laminated portion of the fuel cell, and at least one of the fuel electrode and the air electrode can withstand phosphoric acid under high temperature and at the periphery thereof. As a filler having tackiness and water repellency, a mixture of silicon carbide, a fluororesin and a halogenated oil is filled to give a sealing function.

[Work]

In the present invention, since the filling is filled in the peripheral portion of the electrode itself to form the sealing portion, there is no difference in thickness between the sealing portion and the central portion of the electrode, and a uniform surface pressure is applied to the sealing portion and the central portion of the electrode. Can be applied. Further, since there is no gap between the electrode portion and the seal portion, leakage of gas or electrolytic solution does not occur between them.

〔Example〕

FIG. 1 is a perspective view showing the inside of the embodiment of the present invention with a part cut away, and FIG. 2 is a partial sectional view of FIG.
(4) and (6) to (7) are exactly the same as those in the conventional fuel cell. (9) is a fuel electrode seal part. This fuel electrode seal part (9) consists of a separator plate (1) and a matrix.
It is formed by filling the entire periphery of the fuel electrode (4) having the same outer shape as that of (6) with a filler having resistance to hot phosphoric acid and having adhesiveness and water repellency. The filler is a mixture of silicon carbide, fluororesin such as fluorinated telomer powder (low molecular weight polymer of fluororesin having a reduced degree of polymerization) and halogenated oil such as fluorinated oil. (10) is the air electrode seal part,
Similar to the fuel electrode seal part (9), the separator plate (1) and the matrix (6) are formed by filling the entire periphery of the air electrode (7) having the same outer shape with the above-mentioned filling material. It The mixing ratio of the above-mentioned silicon carbide, fluororesin and halogenated oil is preferably 8 to 12 parts by weight of fluororesin and halogenated oil with respect to 3 parts by weight of silicon carbide.

The fuel cell configured as described above operates in the same manner as the above-mentioned conventional fuel cell, but the fuel electrode seal part (9) and the air electrode seal part (10) are the fuel gas in the fuel flow path (9) and The air in the air channel (3) is prevented from leaking to the outside of the fuel cell formed by stacking and to the other channel. At the same time, the electrolytic solution held in the matrix (6) is prevented from penetrating in the stacking direction and leaking out to the fuel flow channel (2) and the air flow channel (3).

In the above embodiment, the fuel electrode (4) and the air electrode (7) were provided with the seal portions at the peripheral portions thereof, but the fuel electrode (4)
Alternatively, a seal portion may be provided in the peripheral portion of either one of the air electrodes (7). Further, in the above-mentioned embodiment, the entire peripheral portions of the fuel electrode (4) and the air electrode (7), that is, all four sides of these electrodes have the seal structure, but as shown in FIG. 3 and FIG. In addition, a similar effect can be expected even if the fuel electrode (4) and the air electrode (7) have a seal structure only on the two sides. Here, FIG. 3 is a perspective view showing the inside by partially cutting away another embodiment of the present invention, and FIG. 4 is a partial sectional view of FIG.

〔The invention's effect〕

As described above, the present invention forms the seal portion by filling the periphery of at least one of the fuel electrode and the air electrode with a filler having resistance to high temperature phosphoric acid and having adhesiveness and water repellency. Since there is no difference in the thickness between the seal portion and the central portion of the electrode, which results in a uniform surface pressure distribution over the entire electrode, it is possible to obtain a fuel cell with sufficient sealing properties and low contact resistance in the central portion of the electrode. There is. In addition, there is no gap between the seal portion and the electrode portion, and a fuel cell in which no gas or electrolyte solution leaks between the seal portions can be obtained. Furthermore, since the filling of the sealing portion is a heat-resistant phosphoric acid filling, there is an effect that a fuel cell that maintains extremely stable sealing performance can be obtained even when the fuel cell is operated for a long period of time.

[Brief description of drawings]

FIG. 1 is a perspective view showing an inside of a first embodiment of the present invention with a part cut away, FIG. 2 is a partial sectional view of FIG. 1, and FIG. And a perspective view showing the inside,
FIG. 4 is a partial sectional view of FIG. 3, and FIG. 5 is a perspective view showing the inside of a conventional fuel cell with a part cut away. In the figure, (1) is a separator plate, (2) is a fuel flow path, (3)
Is an air flow path, (4) is a fuel electrode, (6) is a matrix, (7) is an air electrode, (9) is a fuel electrode seal portion, and (10) is an air electrode seal portion. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (5)

[Claims] 1. A fuel cell comprising a separator plate, a fuel electrode, a matrix, and an air electrode which are laminated, wherein silicon carbide and a fluororesin are filled in the peripheral portion of at least one of the fuel electrode and the air electrode. A fuel cell comprising: a filler which is a mixture of a halogenated oil and a halogenated oil. 2. A mixing ratio of silicon carbide, fluororesin and halogenated oil is 8 to 12 parts by weight of fluororesin and halogenated oil with respect to 3 parts by weight of silicon carbide. The fuel cell according to item 1. 3. The fuel cell according to claim 1, wherein the fluororesin is a fluorinated telomer powder and the halogenated oil is a fluorinated oil. 4. The fuel cell according to any one of claims 1 to 3, wherein the filling is filled in the entire peripheral portion of at least one of the fuel electrode and the air electrode. 5. The fuel cell according to claim 1, wherein the filling is filled in a part of a peripheral portion of at least one of the fuel electrode and the air electrode.