JPH06338338A - Humidification of high polymer ion exchange film of fuel cell - Google Patents

Abstract

PURPOSE:To transmitting part of cooling water evaporated by cell heat through a distribution current plate to enable humidification of a high polymer ion exchange film by forming the distribution current plate having a channel groove, in which a fuel and an oxidant flow, of a porous substance, and by letting the cooling water run on the back surface. CONSTITUTION:Cell heat is absorbed by the cooling water flowing in cooling water channel grooves 39, 41, and part of the cooling water is evaporated and passes through porous distribution current plates 32 and 36 for fuel and oxidant, at steam, and pure hydrogen and the oxidant flowing in the fuel and oxidant channel grooves 38, 40 are humidified. Part of the cooling water is infiltrated into the distribution current plates 32, 36 in a liquid form and reaches an anode pole 33 and a cathode pole 35, to humidify an electrolyte 34 which is a high polymer ion exchange film of fluororesin. The thermal energy absorbed by the cooling water can be utilized for humidification as it is, and the thermal energy is utilized effectively, while a humidification device is omitted, and the size of the system can thus be drastically reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for humidifying a polymer ion exchange membrane of a fuel cell.

[0002]

2. Description of the Related Art (1) Power Generation Principle of Solid Polymer Electrolyte Fuel Cell FIG. 3 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. 4 shows an example of a conventional solid polymer electrolyte fuel cell operating system. Pure hydrogen fuel 011 and oxidant 012 are
By passing through the pure water 017 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 not used in 18 is used as a fuel together with the residual humidified steam in the case of the remaining pure hydrogen fuel 011 and the residual humidified steam and the water generated by the cell reaction in the case of the remaining oxidant 012. It is discharged to the outside of the battery body 018. Here, the discharged pure hydrogen fuel 011
Has an operating system configuration in which it is recycled by the recycle pump 019 to improve the fuel utilization rate and is reintroduced into the fuel cell main body 018.

(3) Configuration of Gas Separator of Conventional Solid Polymer Electrolyte Fuel Cell FIG. 5 shows the appearance of a gas separator of a conventional internal manifold type or internal header type 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 remaining fuel or 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 discharged to the outside of the fuel cell main body through the fluid discharge hole 026. Has become.

(4) Configuration of Conventional Solid Polymer Electrolyte Fuel Cell FIG. 6 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 once humidified by the humidifiers 015, 016 provided outside as shown in FIG. 4, and the pure hydrogen fuel or the oxidant is used as the fuel cell. Is supplied to. The fuel cell body has a structure in which an electrode assembly is sandwiched between internal manifold type or internal header type separators as shown in FIG. 5, and a cooling water separator for guiding 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 020, respectively.
A or distribution and supply to the anode electrode 032 and the cathode electrode 033 provided on the surface of the electrode assembly 031 through the pure hydrogen fuel flow channel 024A and the oxidant flow channel 024B provided in the oxidant gas separator 020B, respectively. And contributes to the battery reaction. The heat generated in the cell is caused by the cooling water passage groove 036 introduced through the cooling water introduction hole 035 of the cooling water separator 034 arranged behind the pure hydrogen fuel gas separator 020A.
It is absorbed by the cooling water 037 flowing through the fuel cell and contributes to the cooling of the fuel cell body. After that, the remaining pure hydrogen fuel 021A, the oxidant 021B, or the cooling water 037 that absorbs the heat generated by the battery during power generation and becomes hot water is discharged to the outside of the fuel cell body through the discharge holes 026A, 026B, and 038, respectively. It has become so.

[0008]

In such a conventional solid polymer electrolyte fuel cell, as shown in FIG. 4, in order to humidify the pure hydrogen fuel 011 and the oxidant 012, an electric power is provided outside the fuel cell main body. The humidifiers 015 and 016 equipped with the heaters 013 and 014 must be provided, and the entire system has become very large. Further, although the heat energy is applied to the inside of the fuel cell system, the heat energy is discharged from the inside of the fuel cell system, and there is a big problem in energy utilization efficiency.

[0009]

In order to solve the above problems, the present invention sandwiches an electrode assembly formed by sandwiching a polymer ion-exchange membrane between electrodes from both sides, and at the same time sandwiching the electrode assembly from the electrode side, fuel or an oxidant flows. The distribution plate having the flow path groove formed on the electrode side is made of a porous body, and the cooling water is flowed to the outer surface of the distribution plate so that a part of the cooling water vaporized by the heat generation of the battery is distributed. After passing through the plate, the fuel or the oxidant flowing in the flow channel is humidified to humidify the polymer ion exchange membrane, or a part of the cooling water is passed through the distribution plate as a liquid. The method for humidifying the polymer ion exchange membrane of the fuel cell is configured by adding water to the electrode assembly to humidify the polymer ion exchange membrane.

[0010]

In the method of humidifying the polymer ion-exchange membrane of the fuel cell having the above-described structure, when the cooling water absorbs the heat generated by the cell and a part of it vaporizes, it passes through the porous flow distribution plate, so The flowing fuel or oxidant is humidified,
The polymer ion exchange membrane is humidified. Further, when a part of the cooling water passes through the porous flow distribution plate as a liquid, the cooling water that has passed through water hydrates the electrode assembly, so that the polymer ion exchange membrane is humidified.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for humidifying a polymer ion exchange membrane of a fuel cell according to the present invention will be described with reference to the drawings. Note that FIG. 1 shows a schematic configuration of the main part.

As shown in FIG. 1, an anode 33 is provided on the right side of the electrolyte 34, which is a fluororesin-based polymer ion-exchange membrane, and an electrolyte electrode 34 is provided on the left side of the electrolyte 34.
A cathode electrode 35 is provided, and these electrolytes 34,
The anode electrode 33, the cathode electrode 35, and the like form an electrode assembly.

A conductive porous fuel distribution plate 32 is provided on the right side of the anode 33 in the figure, and a conductive porous oxidant distribution is provided on the left side of the cathode 35 in the figure. A plate 36 is provided. A plurality of fuel flow passage grooves 38, through which pure hydrogen as a fuel flows, are formed on the surface of the fuel distribution plate 32 facing the anode 33, and the oxidizer distribution plate 36 is formed on the surface facing the cathode 35 of the oxidizer distribution plate 36. A plurality of oxidant flow channel grooves 40 through which the oxygen flows are formed.

A conductive cooling water separator 31 is provided on the right side of the fuel distribution plate 32 in the drawing, and a conductive cooling water separator 37 is also provided on the left side of the oxidizer distribution plate 37 in the drawing. Has been. A plurality of cooling water flow channels 39 through which cooling water flows are formed on the surface of the cooling water separator 31 facing the fuel distribution plate 32, and the cooling water also flows on the surface of the cooling water separator 37 facing the oxidant distribution plate 36. A plurality of flowing cooling water flow passage grooves 41 are formed.

In such a fuel cell, the cooling water passage groove 3
The cooling water flowing through 9 absorbs the heat generated by the cell, and a part of it becomes vapor to pass through the porous fuel distribution plate 32, humidify the pure hydrogen flowing through the fuel flow channel 38, and pass through the anode 33. The electrolyte 34 is humidified. Also, part of the cooling water
It permeates the porous fuel distribution plate 32 in a liquid state, reaches the anode 33, and humidifies the electrolyte 34.

Similarly, the cooling water flowing through the cooling water flow channel 41 absorbs heat generated by the battery, and a part of the cooling water passes through the porous oxidant flow distribution plate 36 to form the oxidant flow channel groove. The oxidant flowing through 40 is humidified, and the electrolyte is humidified through the cathode electrode 35. In addition, a part of the cooling water permeates the porous oxidant distribution plate 36 in a liquid state, reaches the cathode electrode 35, and humidifies the electrolyte 34.

In the embodiment described above, the cooling water separator 3
Although the cooling water flow passage grooves 39 and 41 are formed in the wirings 1 and 37, the cooling water flow passage grooves may be formed in the flow distribution plate. Such another embodiment will be described with reference to FIG. Note that FIG. 2 shows a schematic configuration thereof. However, the same parts as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 2, a plurality of cooling water flow passage grooves 46 are formed on the facing surface of the fuel distribution plate 43 facing the flat cooling water separator 42, and the cooling water passage grooves 46 face the flat cooling water separator 45. A plurality of cooling water flow channel grooves 47 are also formed on the opposing surface of the oxidizer flow distribution plate 44.

Therefore, as in the above-described embodiment, the cooling water flowing through the cooling water flow channels 46 and 47 passes through these porous flow distribution plates 43 and 44 to humidify pure hydrogen and the oxidizer, and at the same time, the electrolyte Humidify 34.

[0020]

As described above, in the method for humidifying a polymer ion exchange membrane of a fuel cell according to the present invention, vaporized cooling water is passed through a porous flow distribution plate to humidify a fuel or an oxidizer, thereby increasing the temperature. The molecular ion exchange membrane is humidified, or a part of the cooling water is passed through the porous flow distribution plate as a liquid to add water to the electrode assembly to humidify the polymer ion exchange membrane, so the cooling water is absorbed. The heat energy can be used for humidification as it is, and the heat energy can be effectively used. Further, the humidifying device and the electric heater are not required, and the entire system can be significantly downsized.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a main part of an embodiment to which a method for humidifying a polymer ion exchange membrane of a fuel cell according to the present invention is applied.

FIG. 2 is a schematic configuration diagram of a main part of another embodiment.

FIG. 3 is a schematic diagram showing a power generation principle of a solid polymer electrolyte fuel cell.

FIG. 4 is a schematic diagram showing an operating system of a conventional solid polymer electrolyte fuel cell.

FIG. 5 is an external view of a gas separator of a conventional internal manifold type or internal header type solid polymer electrolyte fuel cell.

FIG. 6 is an exploded perspective view showing the configuration of a conventional internal manifold type or internal header type solid polymer electrolyte fuel cell.

[Explanation of symbols]

 31 Cooling Water Separator 32 Fuel Distribution Plate 33 Anode Electrode 34 Electrolyte 35 Cathode Electrode 36 Oxidizer Distribution Plate 37 Cooling Water Separator 38 Fuel Flow Groove 39 Cooling Water Flow Groove 40 Oxidant Flow Groove 41 Cooling Water Flow Groove

Claims (1)

[Claims] 1. A flow distribution plate having a flow path groove formed on the electrode side and having a channel groove through which a fuel or an oxidant flows and an electrode assembly formed by sandwiching a polymer ion exchange membrane between electrodes on both sides from the electrode side. By flowing cooling water to the outer surface of the flow distribution plate, a portion of the cooling water vaporized by the heat generation of the battery is passed through the flow distribution plate, and the fuel flowing through the flow channel or the The polymer ion exchange membrane is humidified by oxidizing an oxidant, or a part of the cooling water is allowed to pass through the flow distribution plate as a liquid and water is added to the electrode assembly to form the polymer ion exchange membrane. A method for humidifying a polymer ion exchange membrane of a fuel cell, which comprises humidifying.