JPH06338332A - Gas separator for solid high molecular electrolytic fuel cell - Google Patents

Abstract

PURPOSE:To manufacture a gas separator at a low cost without performing cutting work and etching work by integrally forming a porous grooved separator, separator supporting plate, separator coating plate and a cooling separator substrate. CONSTITUTION:A porous grooved separator 20 is provided with a plurality of gas flow path grooves 21 in one side surface and further formed of porous material. In a separator supporting plate 30, fitting the separator 20 and also communicating with the gas flow path grooves 21, headers 32, 33 for supplying or discharging gas are formed. A separator coating plate 40 has an opening part 41 for exposing while coating a side of the gas flow path groove 21 of the separator 20. A cooling separator substrate 50, having a plurality of cooling water flow path grooves 51, is connected to the supporting plate 30, to flow cooling water from a supply hole 54 to a discharge hole 55 via a supply header 52, flow path groove 51 and a discharge header 53. The supporting plate 30 and the coating plate 40 can be formed of a high molecular material of light weight at a low cost, and lightening weight and reducing a cost for a call main unit can be contrived.

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. 9 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. 10 shows an example of a conventional solid polymer electrolyte fuel cell operating system. Pure hydrogen fuel 011 and oxidant 012
Is passed through the pure water 017 in the humidifiers 015, 016 heated to a predetermined temperature by the electric heaters 013, 014, thereby containing the moisture equivalent to the saturated steam partial pressure. The moistened pure hydrogen fuel 011 or the oxidant 012 is sent to the fuel cell main body 018. The pure hydrogen fuel 011 or the oxidant 012 not used in the fuel cell main body 018, 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. It is discharged to the outside of the fuel cell body 018. 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 of Conventional Solid Polymer Electrolyte Fuel Cell FIG. 11 shows the appearance of a conventional internal manifold type or internal header type solid polymer electrolyte fuel cell gas separator. 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. 12 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 the humidifier 015, 01 provided outside as shown in FIG.
6 is once humidified and supplied to the fuel cell as a humidified pure hydrogen fuel or an oxidant. The fuel cell main body has a structure in which an electrode assembly is sandwiched between internal manifold type or internal header type gas separators as shown in FIG. 11, and a cooling water separator for guiding cooling water is arranged behind them. The humidified pure hydrogen fuel (H ₂ ) 021A or the humidified oxidant (O ₂ ) 021B is the pure hydrogen fuel gas separator 020A or the pure hydrogen fuel flow channel groove 024A provided in the oxidant gas separator 020B, respectively. , And is distributed and supplied to the anode electrode 032 and the cathode electrode 033 provided on the surface of the electrode assembly 031 through the oxidant channel groove 024B, and contributes to the battery reaction. Battery heat is
The cooling water separator 034 arranged behind the pure hydrogen fuel gas separator 020A is absorbed by the cooling water 037 introduced through the cooling water introduction hole 035 and flowing through the cooling water passage groove 036 to contribute to the cooling of the fuel cell body. There is. After that, the residual fuel, the oxidant, or the cooling water (H ₂ O) 037 that has absorbed the heat generated by the cell during power generation and has become hot water is discharged to the outside of the fuel cell main body through the respective discharge holes 026A, 026B, 038. It has become so.

[0008]

In the operating system of the solid polymer electrolyte fuel cell as shown in FIG. 10, since the pure water storage device serving as the humidifying device is provided outside the fuel cell main body, the entire system becomes large, and An electric heater is required to maintain the temperature of the container and the stored pure water. In addition, the system configuration does not utilize the heat of the cooling water that has become the hot water discharged from the fuel cell main body, and is a system that is wasteful in terms of energy.

That is, since the entire separator is made of one material, the use of expensive materials such as a metal plate and a carbon plate leads to an increase in the manufacturing cost of the fuel cell body. Also,
Since each header and each channel groove must be finished by cutting or etching on each plate, the processing process becomes very complicated and processing cost is increased, leading to an increase in the manufacturing cost of the fuel cell body. Furthermore, in order to manufacture a gas separator that supplies hydrogen gas as a fuel with a carbon plate, a dense carbon plate is required because gas impermeability is required, but such gas impermeability is required. It is very difficult to form a groove in the dense carbon plate that is formed 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 porous grooved separator having a plurality of gas channel grooves and made of a porous material, and a channel for fitting the porous grooved separator and communicating with the gas channel groove to supply or discharge gas. A separator support plate having, a separator coating plate having an opening for covering the gas flow channel groove side of the porous grooved separator fitted to the separator support plate and exposing the gas flow channel groove, and a plurality of cooling water flow channels It is characterized in that it is integrated with a separator support plate having a groove and having the porous grooved separator fitted therein, which is joined and cooled.

The gas separator for a solid polymer electrolyte fuel cell is characterized by using an integral separator coating plate in which the separator supporting plate and the separator coating plate are integrated.

Further, in the gas separator, the separator with porous groove and the cooling separator substrate are made of a conductor, and the separator support plate is made of a non-conductor.

[0015]

In the gas separator having the above structure, since each manifold or header is covered with the separator cover plate, the integral separator cover plate, the flexible electrode assembly is not bent or deformed in the recess, It can be firmly sandwiched and fixed from both sides by the separator cover plate and the integrated separator cover plate. In addition, the entire separator is expensive and does not need to be made of a conductive metal plate or carbon plate, and at least the cooling separator substrate with the cooling water flow channel groove and the porous grooved separator are provided with the conductive metal plate. It suffices to fabricate a carbon plate or the like, and the other separator support plates 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.

[0016]

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 seen from the left side, and FIG. 2 is an exploded perspective view as seen from the right side.

As shown in these drawings, the gas separator 10 according to the present embodiment includes a porous grooved separator 20 made of a porous material, a separator support plate 30 into which the porous grooved separator 20 is fitted, and a separator. It is composed of a cover plate 40 and a cooling separator substrate 50, and these are joined and integrated.

Here, the porous grooved separator 20 has a plurality of gas flow channel grooves 21 extending in the width direction (vertical direction in the figure) formed on one side surface side at a constant pitch, and the material thereof is It is made of a porous material such as carbon.

The separator support plate 30 has a fitting port 31 for fitting the porous grooved separator 20, and a gas supply header communicating with the upper and lower ends of the gas flow channel groove 21 when fitted. 32 and a gas exhaust header 33 are formed.

The separator covering plate 40 is fitted in the fitting port 31 of the separator supporting plate 30 to cover the gas passage side 21 side of the porous grooved separator 20 and the gas passage groove 21 is exposed. An opening 41 for the gas flow channel is formed.

A plurality of cooling water flow passage grooves 51 extending in the width direction (horizontal direction in the drawing) are formed on one side surface of the cooling separator substrate 50 at a constant pitch. A cooling water supply header 52 and a cooling water discharge header 53 that communicate with the flow channel groove 51 are formed at both ends of the cooling water channel groove 51. Then, a part of the cooling water supply header 52 and a part of the discharge header 53 are provided with a cooling water supply hole 54 for supplying and discharging cooling water and a cooling water discharge hole 55 penetrating in the thickness direction. Further, the cooling separator substrate 50
Gas supply holes 5 penetrating in the thickness direction at opposite corners of
6. Gas discharge holes 57 are provided, and when the separator support plate 30 and the cooling separator substrate 50 are joined,
The gas supply hole 56 is arranged so as to communicate with the gas supply header 32, and the one gas discharge hole 57 is arranged so as to communicate with the gas discharge header 33.

The gas separator 10 shown in FIGS.
Shows another embodiment of the present invention, in which the gas separator 10 is formed by using the integral separator coating plate 60 in which the separator supporting plate 30 and the separator coating plate 40 are integrated.
An example of forming the is shown. As shown in the figure, the integral separator coating plate 60 is formed with a fitting recess 61 for fitting the porous grooved separator 20 having the gas channel groove 21 and the porous grooved separator 20. A gas supply header 62 and a discharge header 63 that communicate with the gas flow channel 21 when fitted are formed. Also, when the porous grooved separator 20 is fitted to the integrated separator coating plate 60, the gas channel groove opening 6 is exposed so that the gas channel groove 21 is exposed.
4 are formed.

Since the porous grooved separator 20 and the cooling separator substrate 50 are the same members as those shown in FIGS. 1 and 2, the description thereof will be omitted.

Porous grooved separator 2 having the above structure
0, the separator support plate 30, the separator covering plate 40, and the cooling separator substrate 50 are laminated and integrated to form a pair, and an electrode assembly 70 is sandwiched as shown in FIG. 5 to form a fuel cell. . In the figure, reference numeral 71 is an anode pole, and 72 is a cathode pole. Further, the structure of the electrode assembly 70 is the same as that shown in FIG. 9, and therefore its explanation is omitted.

The same applies to the gas separator 10 using the integrated separator coating plate 60 shown in FIGS.
The operation of the fuel cell of the gas separator 10 shown in FIG. 1 will be described below.

The supply and discharge of gas (pure hydrogen fuel or oxidizer) and cooling water of this fuel cell will be described below with reference to FIG.
2 and FIGS. 5 and 6 will be described.

Humidified pure hydrogen fuel gas (H ₂ ) 73,
Alternatively, the humidified oxidant gas (O ₂ ) 74 is introduced into the battery main body through the gas supply hole 56, and the separator support plate 3
It is distributed and supplied to each gas channel groove 21 provided in the porous grooved separator 20 through the zero gas supply header 32. While passing through the gas flow channel 21, the pure hydrogen fuel gas 73 or the oxidant gas 74 is consumed according to the cell reaction in the electrode assembly 70. The pure hydrogen fuel gas 73 or the oxidant gas 74 that has been consumed and left is collected in the discharge header 33 and then discharged to the outside of the cell body through the gas discharge hole 57.

On the other hand, the battery cooling water 75 is the cooling water flow channel groove 5.
1 is introduced into the battery main body through the cooling water supply hole 54 provided in the cooling separator substrate 50 having 1, and is distributed and supplied to each cooling water flow channel groove 51 through the cooling water supply header 52. While the battery cooling water 75 passes through the cooling water passage groove 51, a part of the battery cooling water absorbs heat generated by the battery and evaporates, and the pure hydrogen fuel gas 73 passes through the porous grooved separator 20.
Alternatively, it becomes possible to humidify the oxidant gas 74 or directly supply a part of the liquid as it is through the porous groove separator 20 to the electrode assembly 70 to secure the water retention state of the electrolyte. There is.

That is, pure hydrogen fuel gas 7 inside the cell
3 or the oxidant gas 74 can be humidified. Then, the remaining battery cooling water 75 is collected in the cooling water discharge port header 53 and discharged to the outside of the battery main body through the cooling water discharge hole 55.

In the fuel cell shown in FIGS. 5 and 6 described above, an example in which each fluid is introduced from both sides of the cell has been shown.
The present invention is not limited to this, and the electrode assembly 70 may be sandwiched by a pair of gas separators 10A and 10B, and each fluid may be introduced from the gas separator 10 on one side thereof, one example of which is shown. It shows in FIG.

As shown in the figure, the gas separator 10A provided on one side is provided so as to penetrate the gas supply hole 56B and the gas discharge hole 57B for supplying and discharging the pure hydrogen fuel gas 73, and the pure hydrogen fuel gas 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.

Next, referring to FIG. 8, the electrolyte 7 constituting the electrode assembly 70 sandwiched between the porous grooved separators 20.
6 shows the action of supplying a part of the battery cooling water as the water content for water retention.

The electrode assembly 70 is sandwiched by the porous grooved separators 20 and 20 having the gas flow channel 21 to which the fuel gas 73 or the oxidant gas 74 is supplied, and the cooling having the cooling water flow channel 51 behind it. Water separator substrate 50, 5
0 is arranged to guide the cooling water 75.

As a result, a part of the battery cooling water 75 absorbs heat generated by the battery and evaporates, and the fuel gas 73 or the oxidant gas 7 is passed through the porous grooved separator 20 which is porous.
4 is humidified, or a part of the liquid is porous and is directly supplied to the electrode assembly 70 through the grooved separators 20 and 20, so that the water retaining state of the electrolyte 76 can be secured. That is, fuel inside the cell,
Alternatively, the oxidizing agent can be humidified.

[0035]

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 having the cooling water flow channel groove and the porous grooved separator are made of an electrically conductive metal. It only has to be made from a plate, carbon plate, etc., and other plates are lightweight and inexpensive gas impermeable non-conductive materials (eg various polymeric materials)
Can be configured with. 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.

The electrode assembly is sandwiched by a porous and grooved separator to which fuel or an oxidant is supplied, and a cooling water separator substrate with a cooling water flow path groove is arranged behind it to guide cooling water. As a result, a part of the battery cooling water absorbs the heat generated by the battery and evaporates, humidifying the fuel or oxidant through the porous grooved separator, or a part of the liquid remains as a liquid directly through the porous grooved separator. It can be supplied to the bonded body to secure the water retention state of the electrolyte.
In other words, it becomes possible to humidify the fuel or oxidant inside the cell, so that the exhaust heat of the cell, which was previously wasted by the cell cooling water, can be effectively utilized inside the fuel cell body to wet the electrolyte. It is possible to maintain the state, and it is not necessary to provide a pure water storage container serving as a humidifying device outside the fuel cell main body, and the entire system can be made compact.

Since each manifold or the header is covered with the separator cover plate or the integral separator cover plate, the flexible electrode assembly is not bent or deformed in the concave portion, and the separator cover plate or the integral separator cover plate is not deformed. Since the plates can be firmly sandwiched and fixed from both sides, deformation and damage 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 configuration diagram of a gas separator according to the present embodiment.

FIG. 3 is a configuration diagram of a gas separator according to another embodiment.

FIG. 4 is a configuration diagram of a gas separator according to another embodiment.

FIG. 5 is a configuration diagram of a solid polymer electrolyte fuel cell.

FIG. 6 is a configuration diagram of a solid polymer electrolyte fuel cell.

FIG. 7 is a configuration diagram of a solid polymer electrolyte fuel cell.

FIG. 8 is a schematic diagram of a method for humidifying an electrode assembly using a porous grooved separator.

FIG. 9 is a power generation principle diagram of a solid polymer electrolyte fuel cell.

FIG. 10 is a schematic diagram of an operating system of a solid polymer electrolyte fuel cell.

FIG. 11 is an external view of a conventional gas separator for a fuel cell.

FIG. 12 is a configuration diagram of a conventional gas separator.

[Explanation of symbols]

 10 Gas Separator 20 Separator with Porous Groove 21 Gas Channel Groove 30 Separator Support Plate 40 Separator Cover Plate 41 Gas Channel Groove Opening 50 Cooling Separator Substrate 51 Cooling Water Channel Groove 54 Cooling Water Supply Hole 55 Cooling Water Discharge Hole 56 Gas supply hole 57 Gas discharge hole 60 Integrated separator coating plate 70 Electrode assembly 71 Anode electrode 72 Cathode electrode 73 Pure hydrogen fuel gas 74 Oxidant gas 75 Cooling water 76 Electrolyte

Claims (3)

[Claims] 1. A gas separator for supplying a fuel gas or an oxidant gas to a solid polymer electrolyte membrane of a fuel cell, which has a plurality of gas passage grooves on one side and is made of a porous material. A separator with a groove, a separator support plate that fits the separator with a porous groove, and has a flow path that communicates with the gas flow groove and supplies or discharges a gas, and a porous material that is fitted to the separator support plate A separator covering plate that covers the gas passage groove side of the grooved separator and has an opening that exposes the gas passage groove, and a separator that has a plurality of cooling water passage grooves and is fitted with the porous grooved separator. A gas separator for a solid polymer electrolyte fuel cell, comprising a support plate and a cooling separator substrate for cooling that are integrated with each other. 2. The solid polymer electrolyte fuel cell gas separator according to claim 1, wherein the separator support plate and the separator coating plate are integrated to form an integral separator coating plate. Gas separator for molecular electrolyte fuel cells. 3. The gas separator for a solid polymer electrolyte fuel cell according to claim 1 or 2, wherein the porous grooved separator and the cooling separator substrate are made of a conductor, and the separator support plate is made of a non-conductor. A gas separator for a solid polymer electrolyte fuel cell, comprising: