JPH06338333A - Gas separator for solid high molecular electrolytic fuel cell - Google Patents

Abstract

PURPOSE:To attain lightening of weight and reduction of a cost of a cell by integrally forming a grooved separator, integral separator coating plate and a separator substrate, and obtaining a gas separator, so that a flow path groove or the like is formed without performing cutting work and etching work. CONSTITUTION:In a gas separator 10, fuel gas or oxidant gas is supplied to a solid high molecular electrolytic film of a fuel cell. This gas separator 10 is divided into a grooved separator 20 having a plurality of gas flow path grooves 21 in one side surface, integral separator coating plate 30 fitting the separator 20 and also having a flow path communicating with the groove 21 to supply/discharge gas further having an opening part 34 for exposing while covering the gas flow path groove 21 and a separator substrate 40 connected to a back side of the separator 20, to manufacture the gas separator 10 integrally formed. In this way, the coating plate 30 can be formed of a molded product of high molecular material or the like of light weight at a low cost without performing complicated cutting work and etching work, and weight lightening and cost reduction of a cell main unit can be attained.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a gas separator for a solid polymer electrolyte fuel cell.

[0002]

[Prior art]

(1) Power Generation Principle of Solid Polymer Electrolyte Fuel Cell FIG. 5 shows an example of a solid polymer electrolyte fuel cell. As the electrolyte 01, a fluororesin-based polymer ion-exchange membrane (for example, a fluororesin-based ion-exchange membrane having a sulfonic acid group) is used, and a catalyst electrode (for example, platinum) 0 is formed on both sides with this center
2, 03 are adhered, and the both surfaces thereof are sandwiched by the porous carbon electrodes 04, 05 so as to be sandwiched to form an electrode assembly 06. Here, hydrogen (H ₂ ) in the fuel supplied to the anode electrode side is hydrogen-ionized on the catalyst electrode (anode electrode) 02, and the hydrogen ion is converted into the electrolyte 0.
Under the presence of water, 1 moves as H ⁺ · xH ₂ O to the cathode side. On the catalyst electrode (cathode electrode) 03, it reacts with oxygen (O ₂ ) in the oxidant and electrons (e ⁻ ) flowing through the external circuit 07 to generate water, which is discharged to the outside of the fuel cell. At this time, the flow of the electrons (e ⁻ ) flowing through the external circuit 07 can be used as DC electric energy. This reaction is shown in "Chemical Formula 1" below.

[0003]

[Chemical 1]

By the way, in order to realize the above-mentioned hydrogen ion permeability in the polymer ion exchange membrane as the electrolyte 01, it is necessary to always keep the membrane in a sufficiently water-retaining state. The fuel or the oxidant is mixed with saturated steam near the operating temperature of the battery (normal temperature to about 100 ° C.), that is, humidified to supply the fuel and the oxidant to the electrode assembly 06 to keep the membrane water-retaining state. I have to.

(2) Conventional Solid Polymer Electrolyte Fuel Cell Operating System FIG. 6 shows an example of a conventional solid polymer electrolyte fuel cell operating system. Pure hydrogen fuel 011 and oxidant 012 are
By passing 017 in pure water in the humidifiers 015, 016 heated to a predetermined temperature by the electric heaters 013, 014, the moisture equivalent to the saturated steam partial pressure is contained. This humidified pure hydrogen fuel 011 or oxidizer 0
12 is fed to the fuel cell main body 018. Fuel cell body 0
The pure hydrogen fuel 011 or the oxidant 012 which was not used in 18 is the fuel cell main body together with the residual humidified steam in the case of the residual pure hydrogen fuel 011 and the residual humidified steam and the cell reaction product water in the case of the residual oxidant 015. 018 is discharged to the outside. Here, the discharged residual pure hydrogen fuel has an operation system configuration in which it is recycled by the recycle pump 019 to be reintroduced into the fuel cell main body 018 in order to improve the fuel utilization rate.

(3) Structure of Gas Separator for Conventional Solid Polymer Electrolyte Fuel Cell FIG. 7 shows the appearance of a conventional internal manifold type or internal header type gas separator for a solid polymer electrolyte fuel cell. As shown in the drawing, the gas separator 020 is provided with a fluid 021 introduced into the fuel cell, that is, a fluid introduction hole 022 into which a fuel, an oxidant, or cooling water is introduced, and the fluid 021 is the fluid. It is introduced into the fuel cell main body through the introduction hole 022, is distributed and supplied to the fluid flow path groove 024 through the inlet side fluid header 023, and contributes to the cell reaction and cooling of the fuel cell. After that, the residual fuel, the oxidant, or the cooling water that has absorbed the heat generated during power generation and becomes hot water is collected in the outlet side fluid header 025, and the fluid discharge hole 0
It is designed to be discharged to the outside of the fuel cell main body through 26.

(4) Configuration of Conventional Solid Polymer Electrolyte Fuel Cell FIG. 8 shows a configuration example of a conventional internal manifold type or internal header type solid polymer electrolyte fuel cell. The pure hydrogen fuel or the oxidant introduced into the fuel cell is used as the humidifiers 015, 016 provided outside as shown in FIG.
Is once humidified by and is supplied to the fuel cell as a humidified pure hydrogen fuel or an oxidant. Figure 1 shows the fuel cell body.
The internal manifold type or the internal header type gas separator as shown in FIG. 1 sandwiches the electrode assembly, and the cooling water separator for guiding the cooling water is arranged behind the electrode assembly. The humidified pure hydrogen fuel 021A or the humidified oxidant 021B is the pure hydrogen fuel gas separator 0, respectively.
20A or pure hydrogen fuel flow channel 024A and oxidant flow channel 024B provided in the oxidant gas separator 020B.
Through, are distributed and supplied to the anode electrode 032 and the cathode electrode 033 provided on the surface of the electrode assembly 031 respectively, and contribute to the battery reaction. The cell heat is generated by the cooling water separator 03 placed behind the pure hydrogen fuel gas separator 020A.
Cooling water passage groove 03 introduced from the cooling water introduction hole 035 of No. 4
It is absorbed by the cooling water 037 flowing through the fuel cell 6 and contributes to the cooling of the fuel cell body. After that, the residual fuel, the oxidizer, or the cooling water 037 that has become hot water by absorbing the heat generated by the battery during power generation is discharged into the discharge holes 026A and 026, respectively.
B, 038 is discharged to the outside of the fuel cell main body.

[0008]

In the solid polymer electrolyte fuel cell as shown in FIGS. 7 and 8, since the entire separator is made of a single material, it is necessary to use an expensive material such as a metal plate or a carbon plate for fuel. This leads to an increase in the manufacturing cost of the battery body. In addition, since each plate has to be finished by cutting or etching the headers and channel grooves, the processing process becomes very complicated and processing costs increase, leading to an improvement in the manufacturing cost of the fuel cell body. .

Further, when a gas separator for supplying hydrogen gas serving as a fuel is manufactured from a carbon plate, a dense carbon plate is required because gas impermeability is required. It is very difficult to form grooves in a dense carbon plate having transparency by cutting.

When the electrode assembly such as a solid polymer electrolyte fuel cell is flexible, the large recessed portions corresponding to the respective manifolds or headers are separated from both sides by the fuel supply separator and the oxidant supply separator. Since it is not sandwiched, the electrode assembly bends or deforms inside the recess of the manifold or the header.

In order to prevent the flexure, a porous material is filled or inserted in the recesses corresponding to the respective manifolds or headers, and a soft electrode assembly is formed on both sides by a fuel supply separator and an oxidant supply separator. There is a problem in that the manufacturing process and materials increase, and the product cannot be manufactured at a low price, if the product is to be sandwiched between them.

[0012]

Means for Solving the Problems A separator according to the present invention for solving the above problems is a gas separator for supplying a fuel gas or an oxidant gas to a solid polymer electrolyte membrane of a fuel cell. A grooved separator having a plurality of gas channel grooves, and a gas channel of the grooved separator having a channel for fitting the grooved separator and communicating with the gas channel groove to supply or discharge gas. An integrated separator cover plate having an opening that covers the groove side and exposes the gas flow path groove, and a separator substrate that is joined on the back side of the grooved separator fitted to the integrated separator cover plate are integrated. It is characterized by

Further, in the gas separator, the grooved separator and the cooling separator substrate are made of a conductor, and the integral separator covering plate is made of a non-conductor.

[0014]

In the gas separator having the above structure, since each manifold or header is covered with the separator covering plate, the separator covering plate is integrated with the separator covering plate without being bent or deformed by the soft electrode assembly. It can be firmly sandwiched and fixed from both sides by the separator coating plate. Further, the entire separator is expensive, and it is not necessary to manufacture it with a conductive metal plate or carbon plate. At least a cooling separator substrate with a cooling water flow channel groove and a grooved separator are provided with a conductive metal plate and carbon plate. The other separator support plate can be made of a lightweight and inexpensive gas impermeable non-conductive material (for example, various polymer materials). Further, each manifold, header, or flow channel can be formed without complicated cutting or etching.

[0015]

EXAMPLES The present invention will be described below based on examples.
FIG. 1 is an exploded perspective view of the gas separator according to the embodiment as viewed from the left, and FIG. 2 is a schematic view of a separator coating plate.

As shown in these drawings, a gas separator 10 according to the present embodiment is provided with a grooved separator 20, an integral separator cover plate 30 for fitting the grooved separator 20 and a rear surface side of the grooved separator 20. And a separator substrate 40, which are joined and integrated.

Here, the grooved separator 20 has a plurality of gas passage grooves 21 extending in the width direction (vertical direction in the drawing) formed on one side surface side thereof at a constant pitch.

The integral separator covering plate 30 has a fitting recess 31 into which the grooved separator 20 is fitted, and a gas supply header which communicates with the upper and lower ends of the gas passage groove 21 when fitted. 32 and a gas exhaust header 33 are formed. Further, the separator coating plate 30 includes
The grooved separator 20 is fitted in the fitting recess 31.
While covering the outer peripheral frame portion on the gas flow channel 21 side, the gas flow channel opening 34 for exposing the gas flow channel 21 is formed.

The separator substrate 40 has a grooved separator 2 in the fitting recess 31 of the integrated separator covering plate 30.
This is for covering the back surface side of the grooved separator 20 in which 0 is fitted. In addition, gas supply holes 41 and gas discharge holes 4 penetrating in the thickness direction are formed at opposite corners of the separator substrate 40.
2 are provided respectively, and when the integrated separator covering plate 30 and the separator substrate 40 are joined, the gas supply hole 4
1 is a gas supply header 32 and another gas discharge hole 42
Are arranged so as to communicate with the gas exhaust header 33, respectively.

A pair of gas separators 10 formed by stacking and integrating the grooved separator 20, the separator covering plate 30 and the separator substrate 40 having the above-described structure are set as a pair, and an electrode assembly 50 is sandwiched as shown in FIG. I am configuring. In the figure, reference numeral 51 is an anode electrode and 52 is a cathode electrode. Further, the structure of the electrode assembly 50 is the same as that shown in FIG. In this embodiment, even when the battery is cooled, the cooling separator 60 having the same structure as the gas separator is used, and the cooling is performed from the back surface of the gas separator on the hydrogen electrode side.

The cooling separator 60 has the same structure as the gas separator 10 described above. In the figure, reference numeral 61 is a cooling water passage groove, 62 is a cooling water supply hole, and 63 is a cooling water discharge hole.
Reference numerals 64 respectively represent cooling water. Since the electrode separator 50 is not arranged between the cooling separator and the gas separator 10, a conventional cooling separator as shown in FIG. 8 may be used.

Next, regarding supply and discharge of gas (pure hydrogen fuel or oxidizer) and cooling water of this fuel cell, FIGS.
3 and FIG.

Humidified pure hydrogen fuel gas (H ₂ ) 53,
Alternatively, the humidified oxidant gas (O ₂ ) 54 is introduced into the battery main body through the respective gas supply holes 41, and each gas flow path provided in the grooved separator 30 through the gas supply header 32 of the separator coating plate 30. It is distributed and supplied to the groove 21. While passing through the gas flow channel 21, the pure hydrogen fuel gas 53 or the oxidant gas 54 is consumed according to the cell reaction in the electrode assembly 50. The remaining pure hydrogen fuel gas 53 or the oxidant gas 54 is collected in the discharge header 33 and then discharged to the outside of the cell body through the respective gas discharge holes 42.

On the other hand, the battery cooling water 64 is the cooling water flow channel groove 6
The cooling water is introduced into the battery main body through the cooling water supply hole 62 provided in the cooling separator 60 having No. 1 and is distributed and supplied to each cooling water flow channel 61 through the cooling water supply header to cool the battery.

In the fuel cell shown in FIG. 3 described above,
An example in which each fluid is introduced from both sides of the battery has been shown, but the present invention is not limited to this, and the electrode assembly 50 is sandwiched by a pair of gas separators 10 and one of the gas separators 10 is sandwiched. Each fluid may be introduced from the above, and an example thereof is shown in FIG.

As shown in the figure, the gas separator 10A provided on one side is provided so as to pass through the gas supply hole 41B for supplying and discharging the pure hydrogen fuel gas 53 and the gas discharge hole 42B. 73 to the gas separator 10
B is supplied and discharged. In this way, the supply hole and the discharge hole for each fluid can be arranged on one side or both sides of the gas separator as required.

[0027]

According to the gas separator of the present invention,
The following effects are achieved.

It is not necessary to manufacture the entire separator from an expensive and electrically conductive metal plate, carbon plate or the like, and at least the cooling separator substrate with the cooling water flow channel groove, and the grooved separator with the electrically conductive metal plate, It only has to be made of a carbon plate or the like, and the other plates can be made of a lightweight and inexpensive gas impermeable non-conductive material (for example, various polymer materials). In addition, since each manifold, header, or flow path groove can be formed without complicated cutting or etching, the fuel cell main body can be made lightweight, and since complicated processing steps are not required, the cost can be very low.

Since each manifold or header is covered with the integrated separator coating plate, the flexible electrode assembly is not bent or deformed in the recess,
Since it can be firmly sandwiched and fixed from both sides by the integral separator coating plate, deformation, damage, etc. of the electrode assembly can be eliminated.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a gas separator according to an embodiment.

FIG. 2 is a schematic view of an integrated separator coating plate according to the present embodiment.

FIG. 3 is a configuration diagram of a solid polymer electrolyte fuel cell.

FIG. 4 is a configuration diagram of a solid polymer electrolyte fuel cell.

FIG. 5 is a power generation principle diagram of a solid polymer electrolyte fuel cell.

FIG. 6 is a schematic diagram of an operating system of a solid polymer electrolyte fuel cell.

FIG. 7 is an external view of a conventional gas separator for a fuel cell.

FIG. 8 is a configuration diagram of a conventional gas separator.

[Explanation of symbols]

 10 Gas Separator 20 Grooved Separator 21 Gas Channel Groove 30 Integrated Separator Cover Plate 34 Gas Channel Groove Opening 50 Electrode Assembly 51 Anode Electrode 52 Cathode Electrode 53 Pure Hydrogen Fuel Gas 54 Oxidant Gas 64 Cooling Water 60 Cooling Separator Substrate 61 Cooling water flow path groove 62 Cooling water supply hole 63 Cooling water discharge hole

Claims (2)

[Claims] 1. A gas separator for supplying a fuel gas or an oxidant gas to a solid polymer electrolyte membrane of a fuel cell, comprising a grooved separator having a plurality of gas flow channel grooves on one side surface,
The grooved separator is fitted and has a channel communicating with the gas channel groove for supplying or discharging gas, and covers the gas channel groove side of the grooved separator and exposes the gas channel groove. A solid polymer electrolyte fuel cell, characterized in that an integrated separator coating plate having an opening and a separator substrate formed by joining the grooved separator fitted to the integrated separator coating plate on the back side are integrated. Gas separator. 2. The gas separator for a solid polymer electrolyte fuel cell according to claim 1, wherein the grooved separator and the separator substrate are made of a conductor, and the integrated separator coating plate is made of a non-conductor. Gas separator for solid polymer electrolyte fuel cells.