JPS5842179A - Fuel battery - Google Patents

Abstract

PURPOSE:To provide the fuel battery which permits the electrolyte feeding passage for feeding electrolyte to a matrix from outside a cell to be constituted easily and provides the stable output of the cell. CONSTITUTION:A necessary pieces of the unit cell in which a matrix 1 is arranged between a fuel electrode 2 and an oxidant electrode 3 are laminated through a separator 6. Grooves 71 for feeding electrolyte are formed on a fuel- electrode basic member 2a, and an electrolyte sink 81 is formed on the separator 6, and the holes 81a which communicate to the groove 71 for feeding electrolyte are formed in the lower part of the separator 6. The holes 91 for communication to electrolyte permit electrolyte to communicate between the groove 71 for feeding electrolyte and the matrix 1, and an electrolyte passage 10 is formed to allow the electrodes, matrix, and the separator to communicate in the edge part of the layer-built battery. When electrolyte is fed, the electrolyte passage 10 is filled with electrolyte, until the electrolyte overflows from the electrolyte sink 8 of each battery and thus the electrolyte sink 8 is filled with electrolyte. In this case, the fuel-electrode basic member 2a is coated with polytetrafluoroethylene for shedding water, in order to prevent the fuel-electrode basic member 2a from being wetted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to fuel cells, and in particular to fuel cells for electric power.

Fuel cells, which produce fuel and oxidant gas energy, are a long-known technology.

A fuel cell consists of a fuel electrode, a fuel electrode, a spaced apart oxidizer electrode,
An electrolyte is placed between these electrodes in contact with them, a separator that also serves as a current collector plate, a fuel electrode, and a gas flow path for fuel gas and oxidant gas formed between the oxidizer electrode and the separator. This is the basic configuration. The electrolyte can then be a solid, a molten paste, a free flowing liquid, or a liquid held within a matrix. Among these, fuel cells using matrix-supported electrolytes are suitable for many applications.

However, in order for a fuel cell using an aqueous electrolyte held within such a matrix to operate under optimal conditions, the matrix must have certain properties. For example, the matrix must be hydrophilic and must be continuous69 and free of holes or cracks to prevent cross-over and mixing of gases within the IJ Lux fuel cell; In order to reduce the internal resistance, the layer must be as thin as possible and in close contact with the catalyst layer. In addition, in order to make the current distribution uniform, it is desirable that the matrix thickness is uniform and the pore size of the matrix is approximately -, and the matrix material is thermally and chemically stable and economical. If a matrix having such properties is electrolytically impregnated and combined with electrodes to assemble a battery, stable performance for a long time can be expected.

However, the matrix and electrodes are porous, and fuel gas and oxidant gas are constantly flowing through the electrode matrix9.
During long-term operation, there was a problem that electrolyte was lost through evaporation and battery performance deteriorated.

To eliminate this problem, the matrix can be impregnated with electrolyte from the gas path of the separator through holes drilled in the electrode substrate, or alternatively, the cell can be made vertically and nine electrolyte passages and an upper electrolyte can be installed at the top of the cell. A method has been proposed in which the matrix is impregnated with an electrolyte through layers. #'s method has the disadvantage that the electrolyte adheres to the electrode base material during electrolyte impregnation, which impedes gas diffusion and reduces battery output. Since nine electrolyte layers are impregnated, there is a drawback that impregnation time is required in the case of large electrodes.

The present invention eliminates these problems, and provides a fuel cell in which an electrolyte supply path for supplying electrolyte to the matrix from outside the cell can be easily configured, and stable cell output can be obtained. With the aim of making this possible, a matrix that holds an electrolyte is provided between a pair of electrodes, a fuel electrode and an oxidizer electrode, and flow paths for fuel gas and oxidizer gas are provided at the fuel electrode and oxidizer electrode, respectively. In a fuel cell formed by stacking unit cells with a separator in between, at least one of a pair of electrodes is provided with a groove-shaped electrolyte supply path that communicates with the matrix through an electrolyte communication hole located in the electrode. The electrolyte supply channel is connected to an electrolyte channel that communicates the electrode, the matrix, and the separator through an electrolyte layer provided in the separator. The first feature is that the separator is provided with a layer, and at least one side of the pair of electrodes of the separator is provided with a groove-shaped electrolyte supply path that communicates with the matrix by all the electrolyte communication holes located in the electrode, A second feature is that this electrolyte supply channel is provided in adjacent electrodes, and a water-repellent layer is provided on the communicating hole in the electrode, the matrix, and the separator, and on the surface of the electrolyte supply channel that contacts the electrode, through an electrolyte layer. That is.

The present invention provides that a fuel electrode and/or an oxidizer electrode have a groove-shaped electrolyte supply channel provided in a separator in contact with these electrodes, and an electrolyte communication hole that communicates this electrolyte supply channel with a matrix. A separator, via an electrolyte layer with an electrolyte supply path provided in the electrode or separator.
It has a passage that communicates between the fuel electrode metrics and the oxidizer electrode, and allows the electrolyte to be supplied to the matrix. This makes it possible to maintain a certain level of electrolyte.

Examples will be described below.

1 to 5 show embodiments in which an electrolyte supply path is provided within the electrode, and the same parts are given the same reference numerals. These examples relate to phosphoric acid fuel cells that use hydrogen-rich gas as a fuel, rll in air as an oxidizer, and phosphoric acid as an electrolyte. FIG. 1 is a partial cross-sectional view of one example. FIG. 2 and FIG. 3 each show a plan view of different main parts. In this figure, 1 is a matrix, and a mixture of silicon carbide and polytetrafluoroethylene, or a phenol resin cloth, etc. is used.

2 is a fuel electrode consisting of a fuel electrode base material 21 and a fuel electrode catalyst layer 2b; 3 is an oxidizer electrode consisting of an oxidizer electrode base material 3a and an oxidizer electrode base material layer 3b; 4 is a fuel electrode gas path; 5 is a gas path for the oxidizer electrode, and 6 is a separator. A required number of unit cells each having a matrix 1 disposed between a fuel electrode 2 and an oxidizer electrode 3 are stacked with a separator 6 interposed therebetween. 7
1 is an electrolyte supply groove provided in 2 m of fuel seed crystal material, 81
91 is an electrolyte layer provided in the separator 6 and having a hole 811 in its lower part communicating with the electrolyte supply groove 71, and 91 is an electrolyte communication hole for communicating the electrolyte between the electrolyte supply #$71 and the matrix l. Reference numeral 10 denotes an electrolytic through hole 4.11 provided at the edge of the stacked battery so as to communicate the '-pole, the matrix and the 7-parameter.

In such an FkW fuel cell, when an electrolyte is supplied, the electrolyte passage 10 is filled with the electrolyte to overflow the electrolyte mass 8 of each cell, and the electrolyte mass 8 is filled with the electrolyte. The electrolyte filled in the waste paper layer 81 flows through the holes 8 at the bottom.
1Jl flows into the electrolyte supply groove 71 and is supplied to the matrix l through the electrolyte communication hole 9t. in this case,
In order to prevent the electrolyte from wetting the fuel electrode base material 2m, the fuel electrode base material 2a is coated with, for example, polytetrafluoroethylene to make it water repellent. Furthermore, when the electrolyte enters the fuel electrode base material 21 due to the electrolyte supply pressure, the electrolyte supply pressure may be lowered by reducing the number of stacked cells serving as the electrolyte supply unit. After the electrolyte is filled in the electrolyte supply groove 71, the electrolyte is removed from the electrolyte passageway 10 to prevent a liquid short circuit caused by the electrolyte. At this time, the electrolyte is also removed from the electrolyte mass 81, but this does not affect the performance.

In the fuel cell constructed as described above, when the amount of electrolyte in the matrix 1 increases due to moisture absorption, the surplus overflows into the electrolyte supply groove 71 through the electrolyte communication hole 91f, and furthermore, the electrolyte Amount 81 is overflowed and stored. Also,
If the electrolyte in the evaporation matrix is insufficient, the insufficient amount is drained into the electrolyte supply groove 7 through the electrolyte communication hole 91.
1 yop is replenished. Therefore, the amount of electrolyte in the matrix 1 is always kept constant, stabilizing the battery performance, and storing excess electrolyte during moisture absorption, so that the fuel electrode catalyst layer 2b and the oxidizer electrode catalyst The layer 3b is not excessively wetted, and the electrode properties are stabilized. Furthermore, when the electrolyte in the electrolyte supply collar 71 decreases, the electrolyte can be replenished through the electrolyte passage 10, so that the electrolyte shortage K.

There is no longer any deterioration in battery performance caused by this. Moreover, the position of the electrolyte communication hole 91 can be determined according to the electrolyte suction ability of the matrix l, so that the electrolyte communication hole 91 can be positioned according to the electrolyte suction ability of the matrix l. Penetration into Trix I is slowed down by making sure it is done at a sufficient rate. In addition, - Since the electrolyte supply groove 71 is provided to limit the electrolyte supply path within the separator 6, the electrode base material is not wetted when electrolyte is supplied, and gas diffusion is not hindered. be.

Figure 1@4 shows a cross section of another embodiment, in which the electrolyte 181. This embodiment differs from the embodiment shown in FIG. 1 in that fibers 12 are filled in the electrolyte supply hole 71 and the electrolyte communication hole 91. The fibers 12 have the effect of improving the rate of impregnation of the stain solute due to their capillary force and making the electrolyte distribution uniform.

The fibers 12 used here include silicon carbide fibers, carbon fibers, glass fibers, 7-dinol resin fibers, and the like. Also, instead of #ll miscellaneous, other hydrophilic materials such as silicon carbide powder, carbon powder may be used as a binder, such as polytetrafluoroethylene,
It is also possible to use a material bound with a volley band, and the same effect can be obtained. Additionally, for example, carbon sheets.

Porous sheets such as silicon carbide sintered bodies may also be used. In addition, the same material as matrix 1 may be used, but in this case matrix 1. Electrolyte communication hole 91, 4 electrolyte supply groove 71. And, between the small holes of the material used in the electrolyte mass 81, the small holes of the material used in the matrix 1 are made small, and the electrolyte communication holes 91. i
t for solyte supply $71. It is desirable that there is a relationship in which the electrolyte amount 81 decreases in order. That is, like this K
By doing this, if a difference is created in the capillary force, the electrolyte amount in the IJ lux will be kept stable due to this difference in capillary force. Additionally, the electrolyte mass 81 and the fibers 12 of the electrolyte supply groove 71 can be omitted if the capillary force is within the above range.

FIG. 5 shows a cross section of another embodiment, and the difference between this embodiment and the embodiment shown in FIG. 1 is that the electrolyte passage 1G
(xoa, tab) and electrolyte mass 81 are provided in both parts of the battery.

With this configuration, the electrolyte replenishment speed can be increased, and at the time of initial filling, the electrolyte is supplied from one electrolyte passage 10a, and the electrolyte is supplied from the other electrolyte passage 10a.
By allowing it to overflow from 0b, filling of the electrolyte can be ensured.

In the embodiments shown in FIGS. 1 to 5 above, a case has been described in which the electrolyte supply *' is provided at the fuel electrode, but it may also be provided at the oxidizer electrode.

It may be provided on both the oxidizer electrodes.

Next, FIGS. 6 to 10 relate to a phosphoric acid fuel cell similar to the embodiment shown in FIG. 1, in which an electrolyte supply path is provided within the separator.

In these figures, the same parts as in FIGS. 1 to 5 are given the same reference numerals. FIG. 6 shows a partial cross section of one embodiment, and FIGS. 7 and 8 show plan views of different main parts.

The difference between the embodiment shown in FIG. 6 and the embodiment shown in FIG. 1 is that the separator 6 has electrolyte supply grooves 7 as shown in FIG.
2 and an electrolyte passage 10 are provided, and an eighth
As shown in FIG. 1, an electrolyte passage 10 and an electrolyte mass 82. And $ for electrolyte supply
An electrolyte communication hole 92 is provided to communicate the electrolyte between the matrix 72 and the matrix l.

In a fuel cell having such a configuration, when supplying an electrolyte, the electrolyte passage 10 is filled with electrolyte to overflow the electrolyte 82 of each cell. The nonacid electrolyte filled with 9-acid enters the electrolyte supply groove 72 from the lower hole 82a and is supplied to the matrix 1 through the electrolyte communication hole 92. in this case,
In order to prevent the electrolyte from wetting the fuel electrode base material 2m, the fuel electrode base material 2m is coated with, for example, polytetrafluoroethylene to make it water repellent. Furthermore, when the electrolyte enters the fuel electrode base material 2a due to the electrolyte supply pressure, it is sufficient to reduce the number of stacked cells forming the electrolyte supply unit and lower the electrolyte supply pressure. , the electrolyte is removed from the electrolyte passageway 10 to prevent a liquid short circuit caused by the electrolyte. At this time, the electrolyte is also removed from the electrolyte mass 82, but the performance is not affected.

In the nine fuel cells constructed as described above, the intake flK
y) When the amount of electrolyte in the matrix 1 increases, the surplus passes through the electrolyte communication hole 92, overflows into the electrolyte supply groove 72, and further overflows into the electrolyte amount 82 and is stored. Also,
When the electrolyte in the matrix l becomes insufficient due to evaporation, the insufficient amount is removed through the electrolyte communication hole 92 to the #7 for electrolyte supply.
2nd supply will be provided.

Therefore, the amount of electrolyte in the matrix l is always maintained at a constant pressure, stabilizing the battery performance, and storing surplus electrolyte when moisture is absorbed, so that the fuel electrode catalyst layer 2
b and the oxidant electrode catalyst layer 3b are not excessively wetted, and the electrode performance is stabilized. Furthermore, when the electrolyte in the electrolyte supply groove 72 decreases, it is sufficient to replenish the electrolyte through the electrolyte passage 1G, thereby eliminating deterioration in battery performance due to electrolyte shortage. Moreover, the electrolyte communication hole 92 is
Since the position can be determined according to the electrolyte suction capacity of the matrix l, the electrolyte can penetrate into the matrix l at a sufficient speed. Also, the electrolyte supply groove 72
Since the electrolyte supply path is limited, the electrode base material is less likely to be wetted when the electrolyte is supplied, and gas diffusion is not hindered. Same as in case.

FIG. 9 shows a cross section of another embodiment, in which the electrolyte amount is 82. This embodiment differs from the embodiment shown in FIG. 6 in that the electrolyte supply groove 72 and the electrolyte communication hole 92 are filled with fibers 12. The effect of filling the fibers 12 and the selection conditions for the material that can be used as the filling material are exactly the same as in the embodiment shown in FIG.

This figure shows a cross section of another embodiment, and the difference between this embodiment and the embodiment shown in FIG. 6 is that the electrolyte passage 10
(10M, 10b) and electrolyte mass 82 are provided at both edges of the cell. The effects in this case are exactly the same as in the fifth prisoner's embodiment.

In the embodiments shown in FIGS. 6 to 1O above, the electrolyte supply groove is provided on the fuel electrode side of the separator.
It may be provided on both the III-forming agent electrodes.

As described above, the present invention provides a fuel cell that can easily configure a round electrolyte supply for supplying electrolyte to p- = r tox from outside the battery, and that can obtain stable cell output. This makes it possible to achieve this goal and has great industrial effects.

[Brief explanation of the drawing]

Figures 1 to @S relate to an embodiment of the fuel cell of the present invention in which an electrolyte supply groove is provided in the electrode. Figure 3 shows the first
4 and 5 are plan views of different clamping parts, respectively, and sectional views of main parts of other different embodiments, and FIGS.
FIG. 10 relates to an embodiment of the fuel cell of the present invention in which an electrolyte supply groove is provided in the separator, and FIG.
7 and 8 are plan views of different main parts from FIG. 6, and FIGS. 9 and 10 are sectional views of main parts of other different embodiments. It is. DESCRIPTION OF SYMBOLS 1... Matrix, 2... Fuel electrode, 2a... Fuel electrode base material, 2b... Fuel electrode catalyst layer, 3... Oxidizer electrode, 3m... Oxidizer electrode base material, 3b ... Oxidizer electrode catalyst layer, 4... Fuel electrode gas path, 5... Oxidizer conventional gas path, 6... Separator, 71.72... Electrolyte supply groove, 81.82. ... Electrolyte layer, 91.92... Electrolyte communication hole, 10... (1 other person)

Claims (1)

[Scope of Claims] 1. A matrix for holding electrolyte is disposed between a pair of electrodes, a fuel electrode and an oxidizer electrode, and a flow of fuel gas and oxidant gas is provided to the fuel electrode and the oxidizer electrode, respectively. In a fuel cell formed by stacking unit cells in which a channel is formed with a separator in between, at least one of the pair of electrodes has a groove-shaped groove that communicates with the matrix through an electrolyte communication hole located in the electrode. an electrolyte supply path is provided, and the electrolyte supply path is connected to an electrolyte passage communicating the electrode, the matrix, and the separator via an electrolyte layer provided in the separator, and the electrolyte communication hole and the A fuel cell characterized in that a water-repellent layer is provided on a surface of the electrolyte supply path that is in contact with the electrode. 2. Claim 1, wherein the groove of the electrolyte supply channel is filled with hydrophilic fibers, a mixture of hydrophilic powder and a binder, a porous sheet, and a matrix material. The fuel cell described. 1. The fuel cell according to claim 1 or 42, wherein the electrolyte communication hole is filled with either a hydrophilic material or a matrix material. The fuel cell according to claim 3, wherein the hydrophilic material is a mixture of hydrophilic material powder and a binder. & The fuel cell according to any one of claims 1 to 4, wherein the electrolyte layer is filled with a hydrophilic material. 6. The fuel cell according to claim 5, wherein the hydrophilic material is a mixture of hydrophilic powder and a binder. 7. The fuel cell according to any one of claims 1 to 4, wherein the electrolyte layer is filled with either a porous sheet or a matrix material. & A patent claim in which the electrolyte holding powers of the matrix, the electrolyte communication hole, the electrolyte supply path, and the electrolyte reservoir are expressed in the order of the electrolyte communication hole, the electrolyte supply path, and the electrolyte layer, with the IJ Lux being the maximum. Range 1 to 7
The fuel cell described in any one of the preceding paragraphs. A single cell, in which a matrix holding an electrolyte is disposed between a pair of electrodes, a fuel electrode and an oxidizer electrode, and flow paths for fuel gas and oxidant gas are formed in the fuel electrode and the oxidizer electrode, respectively. are laminated with a separator in between, in which a groove-shaped electrolyte supply path is provided on at least one side of the pair of electrodes of the separator and communicates with the matrix through an electrolyte communication hole located in an armpit electrode. and the electrolyte supply path communicates with an electrolyte passage that communicates the electrode, the matrix, and the separator via an electrolyte layer provided in the adjacent electrode, the electrolyte communication hole, and the electrolyte supply. A fuel cell characterized in that a water-repellent layer is provided on a surface of the channel in contact with the electrode. 10. The groove of the electrolyte supply channel is filled with any one of hydrophilic fibers, a mixture of hydrophilic powder and a binder, a porous sheet, and a matrix material. 9. The fuel pond according to item 9. 11. The fuel cell according to claim 9 or 10, wherein the electrolyte communication hole is filled with either a hydrophilic material or a matrix material. 12. The fuel cell according to claim 11, wherein the hydrophilic material is a mixture of a hydrophilic material powder and a binder. 1! 13. The fuel cell according to claim 9, wherein the electrolyte reservoir is filled with a hydrophilic material. 14. The fuel cell according to claim 13, wherein the hydrophilic material is a kneaded mixture of hydrophilic powder and a binder. The fuel cell according to any one of claims 9 to 12, wherein the fuel cell is filled with any one of the electrolyte layer, the porous sheet, and the matrix material. la Claim 9, wherein the electrolyte holding power of the matrix, the electrolyte communication hole, the electrolyte supply path, and the electrolyte layer is greatest in the matrix and decreases in the order of the electrolyte communication hole, the electrolyte supply path, and the electrolyte layer. Section 15
The fuel cell described in any one of the preceding paragraphs.