JPH05114407A - Fuel cell - Google Patents

Abstract

PURPOSE:To provide a fuel cell of a stack structure in which deterioration of a gas flow by deformation of a gasket is prevented without using a special reinforcement matrix for the gasket. CONSTITUTION:A stack structure having a gasket 2 disposed around a unit cell 1, and separators 3 interposing these between them is provided. Electrode plates 4, 5 in the unit cell 1 are composed at least of two layers of a reaction layer 7 to face an electrolyte material layer 6 and a substrate layer 8 having a water repellent function, and only the substrate layer 8 having the water repellent function is extended to manifolds 9a, 9b; 10a. 10b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell having a stack structure in which a large number of unit cells are laminated in multiple layers with a separator interposed therebetween.

[0002]

2. Description of the Related Art In a fuel cell having a stack structure in which a large number of unit cells are laminated in multiple layers via separators, a separator facing one of the unit cells is provided with a fuel gas passage consisting of a plurality of parallel grooves. Similarly, the separator facing each other is provided with an air passage made up of a large number of parallel grooves, and the fuel gas and air supplied to these passages react with each other in a single cell to generate electricity.

In such a stack structure composed of a large number of single cells, a gasket for preventing gas leakage is arranged around the single cells. This gasket is deformed by the tightening pressure applied in the stack direction, and a part of the gasket enters the fuel gas passage or the air passage near the manifolds at both ends of the fuel gas passage or the air passage to narrow the flow passage cross-sectional area. There are cases. Therefore, there is a problem that the gas flow rate decreases and the power generation efficiency decreases.

In order to prevent such deformation of the gasket, Japanese Patent Laid-Open No. 207562/1984 proposes a gasket using a metal plate coated with a fluororesin. However, it is unavoidable that the use of such a special reinforcing member such as a metal plate complicates the mechanism and raises the cost.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fuel cell having a stack structure which prevents a decrease in gas flow rate due to deformation of a gasket without using a special reinforcing member for the gasket. It is in.

[0006]

According to the present invention, which achieves the above object, a single cell constructed such that an electrolyte matrix layer is sandwiched between two electrode plates, an anode and a cathode, and a gasket is arranged around the unit cell. In a state of being laminated in multiple layers with a separator interposed, a fuel gas passage is provided on the separator surface facing one of the unit cells, and an air passage is provided on the separator surface facing the other, and the fuel gas passage and the air passage are provided. In a fuel cell in which air supply and exhaust manifolds are provided at both ends, the electrode plate is composed of at least two layers of a reaction layer facing the electrolyte matrix layer and a base material layer having a water generating function. It is characterized in that only the base material layer having the water generating function is extended to the manifold of the air passage and the fuel gas passage.

By extending the base material layer having a certain rigidity to the manifold as described above, the base material layer is interposed between the fuel gas passage and the air passage near the manifold and the gasket. The gasket does not deform and enter the fuel gas passage or the air passage due to the tightening pressure. Further, since the base material layer is provided with a water-releasing function, the electrolyte solution of the electrolyte matrix layer is prevented from flowing out to the manifold, and a reliable sealing property is ensured.

[0008]

EXAMPLE FIG. 1 shows a main part of a fuel cell according to an example of the present invention. As shown in FIG. 1, in the fuel cell, a gasket 2 is arranged in a plane shape on the outer periphery of a single cell 1 (see FIG.
(See (A), (B), (C)), and FIG.
The separator 3 as shown in (A) and (B) is arranged to form a multilayer stack. The separator 3 is
The fuel gas passage 3a having a plurality of parallel grooves is formed on one surface, and the air passage 3 is also formed of a plurality of parallel grooves on the other surface.
b is arranged so as to be orthogonal to the fuel gas passage 3a. In such a separator 3, the fuel gas passage 3a faces one surface of the unit cell 1 and the air passage 3b faces the other surface.
To face each other. Inner manifolds 9a and 9b for supplying and exhausting fuel gas (hydrogen, etc.) are provided at both ends of the fuel gas passage 3a.
Outer manifolds 10a and 10b (see FIG. 2C) for supplying and exhausting reaction air are provided at both ends of b.

The unit cell 1 is constructed by interposing an electrolyte matrix layer 6 between two electrode plates, a cathode plate 4 and an anode plate 5. The cathode plate 4 and the anode plate 5 are composed of a reaction layer 7 arranged so as to face the electrolyte matrix layer 6, and a base material layer 8 bonded to the reaction layer 7 via a water-generating layer 8a. Has been done. The electrolyte matrix layer 6 is composed of two porous layers holding an electrolytic solution (phosphoric acid, etc.), one of which is a dense layer 6a having an excellent function of retaining the electrolytic solution, and the other is the transmission of the electrolytic solution. The rough layer 6b having an excellent function is used. This electrolyte matrix layer 6
Is a communication hole 11 (see FIG. 2) provided on the side surface of the gasket 2.
(See FIG. 4B) and the connecting pipe 12,
As shown in (A), (B), (C), etc., they are connected to the electrolytic solution reservoir 13. As described above, the electrolytic solution matrix layer 6 is composed of two coarse and dense layers and is connected to the electrolytic solution reservoir 13, so that when the fuel cell is turned on and off, moisture absorption and temperature rise during stoppage are stopped. When the volume of the electrolytic solution increases due to thermal expansion or the like, the electrolytic solution is prevented from entering the electrode.

The reaction layer 7 of the electrode plate has a porous structure in which carbon black carrying a catalyst is bound by using a fluororesin as a binder. The base material layer 8 is made of so-called carbon paper and has a relatively large rigidity, for example, a porous structure in which carbon fibers are bound by a small amount of a resin binder. The base material layer 8 has a water-releasing function by bonding the water-releasing layer 8a on one surface. As the water-releasing function of the base material layer 8, the water-repellent resin such as the fluororesin is used as the binder of the base material layer 8 in addition to the water-repellent layer 8a provided as an example as shown in the figure. The base material layer itself may be provided with a water-releasing function by using.

In the cathode plate 4 and the anode plate 5 having such an electrode plate structure, the former cathode plate 4 has its base material layer 8 extended to the inner manifolds 9a and 9b together with the water-releasing layer 8a (see FIG. 1 and FIGS. 2 (A) and 2 (B)), and the latter anode plate 5 also extends the base material layer 8 to the outer manifolds 10a and 10b together with the water-generating layer 8a (FIG. 2 (C)). )reference). Therefore, the base layer 8 having a constant rigidity with the water-emitting layer 8a is the gasket 2
And the fuel gas passage 3a near the manifold and the air passage 3b are interposed, so that even if the gasket 2 is strongly crushed in the stacking direction, it does not enter the grooves of the passages 3a and 3b, It does not narrow the flow path. Therefore, the flow rates of the fuel gas and the reaction air are secured and the power generation efficiency is not reduced. Further, since the base material layer 8 extends to the manifold together with the water-generating layer 8a, the electrolytic solution of the reaction layer 7 of the electrode plate does not flow out to the manifold, and the reliable sealing property is secured.

Liquid sealing materials 15 and 16 as sealants are inserted into the outer peripheral edge portions of the electrode plates 4 and 5 so as to be sandwiched between them and the gasket 2. The inner manifolds 9a, 9a are formed by these liquid sealing materials 15, 16.
b and the outer manifolds 10a and 10b are prevented from seeping out.

[0013]

As described above, according to the present invention, the base material layer of the electrode plate is extended to the manifold. Therefore, the base material layer having a certain rigidity has a fuel gas passage, an air passage and a gasket near the manifold. And the gasket, it is possible to prevent the gasket from deforming and entering the fuel gas passage or the air passage due to the tightening pressure. Moreover, since the base material layer has a water-releasing function,
The electrolyte solution of the electrolyte matrix layer does not flow out to the manifold, and a reliable sealing property can be secured.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a main part of a fuel cell according to an embodiment of the present invention.

2 shows an assembly of a unit cell and a gasket used in the fuel cell of FIG. 1, where A is a plan view, B is a side view in which a portion taken along the line AA of FIG. It is a bottom view.

FIG. 3 shows a separator used in the fuel cell of FIG. 1, where A is a bottom view and B is a sectional view taken along the line BB of FIG.

4A, 4B and 4C are schematic diagrams showing examples of communication between a single cell and an electrolyte reservoir.

[Explanation of symbols]

1 Single cell 2 Gasket 3
Separator 3a Fuel gas passage 3b Air passage 4 Cathode plate (electrode plate) 5 Anode plate (electrode plate) 6 Electrolyte matrix layer 7 Reaction layer 8 Base material layer 8a Water release layer 9a, 9b Inner manifold 10a, 10b
Outer manifold

Claims (1)

[Claims] 1. A single cell configured such that an electrolyte matrix layer is sandwiched between two electrode plates, an anode and a cathode, is laminated in multiple layers with a separator interposed with a gasket placed around it. A fuel gas passage is provided on the separator surface facing one of the unit cells, and an air passage is provided on the separator surface facing the other, and air supply and exhaust manifolds are provided at both ends of the fuel gas passage and the air passage, respectively. In the provided fuel cell, the electrode plate is composed of at least two layers of a reaction layer facing the electrolyte matrix layer and a base material layer having a water-releasing function, and only the base material layer having the water-releasing function is provided. A fuel cell that extends to the manifold of the air passage and the fuel gas passage.