JP2002367630A - Fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell with good drainage. SOLUTION: The fuel cell is formed by interposing a solid polymer electrolyte 10 between a hydrogen supplying plate 13, having flow paths 20, 21 through which, the gas containing hydrogen and oxygen or air as main fuel flows, and an oxygen supplying plate 14, through electrodes 11, 12 having catalyst. The cross section of the gas flow path 21 of the oxygen supplying plate 14 is made bigger than the cross section of the gas flow path 20 of the hydrogen supplying plate 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a fuel cell using a solid polymer electrolyte membrane.

[0002]

2. Description of the Related Art In a conventional fuel cell using a solid polymer electrolyte, for example, as shown in FIG. 10, a catalyst 101, 102, a hydrogen electrode (negative electrode) 103, a waterproof Air electrode (positive electrode) provided with membrane 105
104. At the hydrogen electrode 103, hydrogen gas supplied from the outside passes through the hydrogen electrode 103, reaches near the reaction zone, is absorbed by the catalyst 101, and becomes active hydrogen.

[0003] The hydrogen atoms react with hydroxyl ions in the electrolyte to become water as shown in the following formula, and at this time, electrons are sent to the air electrode 104.

H ₂ + 2OH ⁻ → 2H ₂ O + 2e ⁻ On the other hand, at the air electrode 104, the air electrode 1
Two electrons are received from the substrate 04 and oxygen molecules supplied from the outside react with water from the electrolyte 100 to generate hydroxyl ions.

[0005] _{1 / 2O 2 + H 2 O} → 2OH - hydroxy generated in the air electrode ions react with hydrogen ions moved to the middle electrolyte 100 to form water, to form a circuit of the whole.

Accordingly, the reaction of the whole battery is H ₂ + 1 / 2O ₂ → 2H ₂ O, and hydrogen in the fuel gas and oxygen in the air react to generate water.

[0007]

As shown in FIG. 11, an actual fuel cell comprises an electrolyte 100 sandwiched between an air supply plate 106 and a hydrogen supply plate 107. A pipe 108 and a drain pipe 109 are connected, and a hydrogen supply pipe 110 and an exhaust gas pipe (not shown) are connected to the hydrogen supply plate 107.

FIG. 12 is a cross-sectional view taken along line FF of FIG. 11. The air supply plate 106 and the hydrogen supply plate 107 are used to connect the electrolyte 100 to the negative electrode side electrode sheet 1 with a catalyst.
11 and positive electrode side catalyst electrode sheet (with waterproof sheet) 112
And a structure in which hydrogen gas or oxygen gas is supplied by piping. In many cases, gas passages 113 and 114 are formed in the air supply plate 106 and the hydrogen supply plate 107, and the grooves 115 and 11 are formed in the electrode sheets 111 and 112.
6 are provided.

In practice, in order to form a multi-layer structure, the electrodes are insulated and separated by a separator or the like. Therefore, in assembling the cells, it is necessary to give consideration to gas leakage to the entire periphery of each cell, and it is necessary to provide a pipe on this plate-shaped member and supply the raw material gas.

It is important to control the concentration of water in the electrolyte with respect to the ion transfer efficiency of the electrolyte.

In the conventional fuel cell shown in FIGS. 11 and 12, the gas flow path is narrow and long, the resistance of the gas flow is increased, and water is condensed to form water droplets. There were places where the oxidizing gas did not reach, and variations in the water concentration distribution occurred.

Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide a fuel cell which can drain well.

[0013]

In order to achieve the above object, the invention of claim 1 is directed to a method in which a solid polymer electrolyte is supplied through a catalyst-equipped electrode by flowing a gas containing hydrogen and oxygen or air as a main fuel. A fuel cell formed between a hydrogen supply plate having a flow path and an oxygen supply plate, wherein a gas flow path cross section of the oxygen supply plate is formed larger than a gas flow path of the hydrogen supply plate.

According to a second aspect of the present invention, there is provided the fuel cell according to the first aspect, wherein the oxygen supply plate is formed in two stages, and a gas flow path is formed in the oxygen supply plate.

According to a third aspect of the present invention, electrodes for forming gas flow paths are provided inside and outside the solid polymer electrolyte formed in a cylindrical shape, and the cross section of the gas flow path on the oxygen supply side is formed larger than the hydrogen supply side. It is a fuel cell.

According to a fourth aspect of the present invention, a cylindrical internal electrode having a cylindrical positive electrode having a gas flow path for supplying oxygen on the outer periphery is provided on the inner periphery of the solid polymer electrolyte. A cylindrical negative electrode external electrode having a hydrogen supply gas flow path formed on the inner periphery was provided, and a passage for draining water generated in the oxygen supply gas flow path was formed at the center of the positive electrode internal electrode. A fuel cell according to claim 3.

According to a fifth aspect of the present invention, there is provided the fuel cell according to the fourth aspect, wherein a drain pipe is connected to the passage, and a dehumidifier for controlling the moisture concentration of the gas path for supplying oxygen is connected to the drain pipe. is there.

According to a sixth aspect of the present invention, there is provided a cylindrical negative electrode side inner electrode having a hydrogen supply gas flow path formed on the outer periphery on the inner periphery of the solid polymer electrolyte. 4. The fuel cell according to claim 3, wherein a positive electrode side external electrode formed of a double cylindrical body having an oxygen supply gas flow path formed on an inner periphery thereof is provided.

According to a seventh aspect of the present invention, a drain pipe is connected to the gas flow path of the positive electrode side external electrode, and a dehumidifier for controlling the water concentration of the gas flow path for supplying oxygen is connected to the drain pipe. Item 7. A fuel cell according to Item 6.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

1 to 3 show schematic views of a fuel cell according to the present invention.

FIG. 1 is a schematic perspective view of a fuel cell according to the present invention, FIG. 2 is a sectional view taken along line AA of FIG.
Shows a conceptual diagram of the cross-sectional view of FIG. 2 as viewed obliquely.

In the fuel cell unit, a solid electrolyte 10 is provided with a negative electrode-side catalyst electrode sheet (with a waterproof sheet) 11 and a positive electrode side electrode sheet 12.
3 and a positive electrode side oxygen supply plate 14, and a sealant 15 is provided around the hydrogen supply plate 13 and the positive electrode side oxygen supply plate 14,
A hydrogen supply pipe 16 is connected to the hydrogen supply plate 13, and an oxygen supply pipe 17 and a drain pipe 18 are connected to the oxygen supply plate 14.

In the hydrogen supply plate 13 and the oxygen supply plate 14, gas flow paths 20, 21 for supplying hydrogen and oxygen to the electrode sheets 11, 12 are formed, respectively.

The oxygen supply plate 14 is formed by stacking two conventional oxygen supply plates and connecting gas passages 21 at appropriate locations in the vertical direction.

In this fuel cell, hydrogen is supplied from the hydrogen supply pipe 16 to the gas flow path 20 of the hydrogen supply plate 13 on the negative electrode side, and oxygen or an oxygen source is supplied from the oxygen supply pipe 17 to the gas flow path 21 of the oxygen supply plate 14. Is supplied and reacted, electric power is generated, and the generated water is supplied to the gas passage 2
Emitted from 1.

At this time, since the gas flow path 21 has a large cross section, the drainage becomes good.

Although not shown in FIGS. 1 to 3, a pressure regulating valve and a dehumidifier are connected to the end of the port of the drain pipe 18 on the oxygen or oxygen source side of the oxygen supply plate 14,
Adjust the water concentration in the cell.

In the operation of this fuel cell, for example, hydrogen was set at 2 atm and oxygen was set at 1 atm. When air was used as the oxygen source, the pressure was 5 atm.

When the fuel cell described above was supplied with the above-mentioned fuel gas and operated, an electromotive force of 0.8 V was generated.

The plates 13 and 14 are stacked in multiple stages and have a function as a separator. A compression-processed product made of carbon as a main raw material is used. Not dependent on material.

FIGS. 4 to 6 show another embodiment of the present invention. FIG. 4 is a schematic overall view of a fuel cell, and FIGS.
4 is a sectional view taken along line BB of FIG. 4, and FIG. 6 is a sectional view taken along line CC of FIG.

First, the fuel cell 28 is formed in a columnar shape, and sandwiches a solid polymer electrolyte 30 formed in a cylindrical shape.
A cylindrical positive electrode side internal electrode 32 and a cylindrical negative electrode side external electrode 34
Are provided. A groove-shaped gas flow path 31 is formed on the outer periphery of the positive electrode side internal electrode 32 so as to supply oxygen to the solid polymer electrolyte 30, and the inner periphery of the negative electrode side external electrode 34 is formed on the solid polymer electrolyte 30. A groove-shaped gas flow path 33 is formed to supply hydrogen. This positive electrode side internal electrode 32
A passage 35 for supplying oxygen and discharging generated water is formed on the center side of the gas passage 31. In addition,
The catalyst layer and the waterproof layer are provided although omitted in the figure.

As shown in FIG. 4, a supply pipe 41 is connected to the hydrogen gas source 40, and the supply pipe 41 is connected to a gas passage 43 connected to the gas flow path 33 of the negative electrode 34. A gas pipe 45 is connected to the oxygen gas source 44, the pipe 45 is connected to a passage 35, a drain pipe 46 is connected to a lower portion of the passage 35, and the drain pipe 46 is connected to a pressure regulating valve, a cooler, and the like. A dehumidifier 47 is connected, and the water removed by the dehumidifier 47 is drained from a drain hole 48.

Reference numeral 49 denotes a current / voltmeter.

In this embodiment, the hydrogen gas source 4
Since the supply of the fuel gas from the O and oxygen gas sources 44 is merely performed by supplying the gas to the gas flow paths 33 and 31 and flowing in the axial direction, the piping becomes easy.

The water produced from the positive electrode side is supplied to the gas passage 31
And the passage 35 are connected to each other, and the cross section of the passage is the hydrogen gas passage 3
3, the water generated in the gas flow path 31 is discharged from the gas flow path 31 to the passage 35, and can be drained well through the drain pipe 46.

At this time, by adjusting the amount of water drained to the drain hole 48 by the dehumidifier 47, the water concentration in the gas passage 31 can be freely adjusted, and the water condenses in the gas passage 31. The drainage does not become bad.

7 to 9 show another embodiment of the present invention. FIG. 7 is a schematic overall view of a fuel cell, and FIG.
7 is a sectional view taken along line DD of FIG. 7, and FIG. 9 is a sectional view taken along line EE of FIG.

First, the fuel cell 52 is formed in a cylindrical shape, and has a negative electrode side internal electrode 54 having a hydrogen gas flow path 53 formed therebetween with a solid electrolyte 50 interposed therebetween, and an oxygen first gas flow path 5.
5 is provided, and a positive electrode side external second electrode 56 having a second gas flow path 57 formed outside thereof is provided.
An electrode 58 is provided and the first gas flow path 55 is provided.
And the second gas flow path 57 are connected to each other at an appropriate position and formed. The catalyst layer and the waterproof layer are provided although omitted in the figure.

As shown in FIG. 7, a supply pipe 61 is connected to the oxygen gas source 60, and the supply pipe 61 is connected to the gas flow paths 55, 5 of the positive first external electrode 56 and the second external electrode 58.
A gas pipe 65 is connected to the hydrogen gas source 64, and the pipe 65 is connected to the gas channel 53 of the negative electrode 54.

The drain pipe 66 below the fuel cell 52
Is connected to the first gas passage 55 and the second gas passage 57,
A dehumidifier 67 including a pressure regulating valve and a cooler is connected to the drain pipe 66, and water removed by the dehumidifier 67 is drained from a drain hole 68.

Reference numeral 69 denotes an ammeter.

In this embodiment, contrary to the embodiments shown in FIGS. 4 to 6, the gas from the hydrogen gas source 64 is made to flow toward the center and the oxygen from the oxygen gas source 60 is made to flow to the outside.
By forming and flowing 5,57 in two stages, it is possible to drain well. At this time, by adjusting the amount of water discharged to the drain hole 68 by the dehumidifier 67, the water concentration in the gas flow paths 55 and 57 can be freely adjusted and the gas flow paths 55 and 57 can be adjusted.
There is no possibility that the water will condense in the inside and the drainage will become defective.

By using a columnar fuel cell as described above, piping to each gas flow path for a plurality of cells becomes easy. The fuel cell may be either vertical or horizontal, taking into consideration the generated water drainage. In addition, the thickness of the cylindrical cell does not depend on the electromotive force in principle, and can be freely designed.

[0046]

As described above, according to the present invention, the drainage can be improved by forming the oxygen gas flow path in two steps and widening the flow path.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a conceptual diagram of the cross-sectional view of FIG. 2 as viewed obliquely.

FIG. 4 is a schematic overall view of a fuel cell according to another embodiment of the present invention.

FIG. 5 is a sectional view taken along line BB of FIG. 4;

FIG. 6 is a sectional view taken along line CC of FIG. 4;

FIG. 7 is a schematic overall view of a fuel cell according to another embodiment of the present invention.

FIG. 8 is a sectional view taken along line DD of FIG. 7;

FIG. 9 is a sectional view taken along line EE of FIG. 7;

FIG. 10 is a diagram showing a basic structure of a fuel cell unit.

FIG. 11 is a schematic perspective view showing a conventional fuel cell unit.

FIG. 12 is a sectional view taken along line FF of FIG. 11;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Solid polymer electrolyte 11, 12 Electrode with a catalyst 13 Hydrogen supply plate 14 Oxygen supply plate 20, 21 Gas flow path

Claims (7)

[Claims] 1. A fuel comprising a solid polymer electrolyte sandwiched between an oxygen supply plate and a hydrogen supply plate having a gas flow path through which a gas containing hydrogen and oxygen or air as a main fuel is formed via an electrode with a catalyst. A fuel cell, wherein a cross section of a gas passage of an oxygen supply plate is formed larger than a gas passage of a hydrogen supply plate. 2. The fuel cell according to claim 1, wherein the oxygen supply plate is formed in two stages, and a gas flow path is formed in the oxygen supply plate. 3. An electrode for forming a gas flow path inside and outside a solid polymer electrolyte formed in a cylindrical shape, and a cross section of the gas flow path on the oxygen supply side is formed larger than that on the hydrogen supply side. Fuel cell. 4. A cylindrical positive electrode having a gas flow path for supplying oxygen on the outer periphery thereof is provided on the inner periphery of the solid polymer electrolyte, and hydrogen is supplied on the outer periphery of the solid polymer electrolyte and on the inner periphery thereof. 4. A cylindrical negative electrode-side external electrode having a gas flow path formed therein, and a passage for draining water generated in the gas flow path for oxygen supply is formed at the center of the internal electrode on the positive electrode side. Fuel cell. 5. The fuel cell according to claim 4, wherein a drain pipe is connected to the passage, and a dehumidifier for controlling the moisture concentration in the gas flow path for supplying oxygen is connected to the drain pipe. 6. A cylindrical negative electrode having a gas flow path for supplying hydrogen on the outer periphery thereof is provided on the inner periphery of the solid polymer electrolyte, and oxygen is supplied on the outer periphery of the solid polymer electrolyte and on the inner periphery thereof. The fuel cell according to claim 3, further comprising a positive electrode-side external electrode formed of a double cylindrical body having a gas flow path formed therein. 7. The fuel according to claim 6, wherein a drain pipe is connected to the gas flow path of the positive electrode side external electrode, and a dehumidifier for controlling the moisture concentration of the gas flow path for supplying oxygen is connected to the drain pipe. battery.