JPH10172587A - Solid highpolymer type fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid highpolymer type fuel cell which can be equipped with a long lifetime. SOLUTION: A solid highpolymer type fuel cell includes unit cells 42 in which a fuel electrode 61 and oxidator electrode 62 are arranged in such a way as pinching a highpolymer electrolyte film 60, wherein the two electrodes 61 and 62 are formed as not overlapping while their edge parts A and B in the regions contacting with the electrolyte film 60 are pinching the film 60.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid electrolyte using a polymer film having hydrogen ion conductivity or a composite material of inorganic or organic material powder having hydrogen ion conductivity and a polymer material as a binder as an electrolyte. The present invention relates to a polymer fuel cell.

[0002]

2. Description of the Related Art In recent years, fuel cells have attracted attention as high-efficiency energy conversion devices. Depending on the type of electrolyte used, fuel cells are broadly classified into low-temperature operating fuel cells such as alkaline type, solid polymer type and phosphoric acid type, and high-temperature operating fuel cells such as molten carbonate type and solid oxide type. You.

Among them, a polymer electrolyte fuel cell (PEFC) using a polymer electrolyte membrane having ion conductivity as an electrolyte has a compact structure, a high output density, and can be operated with a simple system. For this reason, it is attracting attention as a power source for space, remote islands, fixed sites, vehicles, and the like.

Examples of the polymer electrolyte membrane include a polystyrene-based cation exchange membrane having a sulfonic acid group, a mixed substance of fluorocarbon sulfonic acid and polyvinylidene fluoride, and a substance obtained by grafting trifluoroethylene onto a fluorocarbon matrix. It has been known.
Recently, a perfluorocarbon sulfonic acid membrane (for example, Nafion: trade name, manufactured by DuPont) or the like is used.

A polymer electrolyte fuel cell using such a polymer electrolyte membrane as an electrolyte is usually configured as a stacked structure in which a plurality of unit cells 1 formed as shown in FIG. 17 are stacked.

The unit cell 1 is formed of a polymer electrolyte membrane 10 and a porous body supporting a catalyst such as platinum, and has a fuel electrode 11 arranged so as to sandwich the polymer electrolyte membrane 10 therebetween.
And an oxidizer electrode 12, a porous fuel electrode-side current collector 13 disposed in contact with the back surface of the fuel electrode 11, and an oxidizer electrode 12.
And a plurality of fuel supplies formed on a surface of the fuel electrode side current collector 13 which is in contact with the fuel electrode 11 to distribute and supply fuel gas to the fuel electrode 11. A groove 15; a plurality of oxidant supply grooves 16 formed on a surface of the oxidant electrode side current collector 14 which is in contact with the oxidant electrode 12 to distribute and supply an oxidant gas to the oxidant electrode 12; A cooling plate 17 provided on the back side of the electric body 13, a cooling water guide groove 18 provided on the cooling plate 17 for guiding cooling water, and a part of the water guided by the cooling water guide groove 18 And a humidified water permeable plate 19 for controlling the amount of transfer to the fuel electrode side current collector 13.

[0007] In FIG. 17, reference numerals 20 and 21 surround the periphery of the membrane electrode assembly composed of the polymer electrolyte membrane 10, the fuel electrode 11 and the oxidant electrode 12 to prevent leakage of fuel gas and oxidant gas. Further, a frame-shaped spacer for securing insulation between the fuel electrode side current collector 13 and the oxidant electrode side current collector 14 is shown. When the cooling plate 17 is not interposed, the fuel electrode side current collector 13 and the oxidant electrode side current collector 14 may be integrated.

The polymer electrolyte membrane 10, the fuel electrode 11, and the oxidizer electrode 12 are formed in a sheet shape, and have a thickness of 1 mm or less to reduce internal resistance. Further, the polymer electrolyte membrane 10, the fuel electrode 11, and the oxidizer electrode 1
2 is often formed in a square shape in consideration of productivity. The area is determined by a current value required for power generation and a current value per unit area, that is, a current density, and is generally set to 100 cm ² or more, that is, 10 cm or more on one side.

The fuel electrode side current collector 13 and the oxidant electrode side current collector 14 are composed of the polymer electrolyte membrane 10 and the respective electrodes 11 and 12 as shown in FIG. Many of them are formed in a square shape according to the shape of. A square area is set in the center according to the shape of each of the poles 11 and 12, and a plurality of fuel gas supply grooves 15 (oxidant gas supply grooves 16) are provided in parallel with this square area. Cooling plate 17
Similarly, a square area is set in the center according to the shape of each of the poles 11 and 12, and a plurality of cooling water guide grooves 18 are provided in parallel with this square area.

Both ends of the fuel gas supply groove 15 are provided in the stacking direction at the peripheral edge of the stacking element via communication passages 22 and 23 formed at substantially the same depth as the fuel gas supply groove 15. It communicates with the supply manifold 24 and the fuel gas discharge manifold 25. Similarly, both ends of the oxidizing gas supply groove 16 are connected to the oxidizing gas supply manifold 2.
6 and the oxidant gas discharge manifold 27, and both ends of the cooling water guide groove 18 are connected to a cooling water supply manifold 28 and a cooling water discharge manifold 29. On the other hand, the humidified water permeable plate 19 is formed of a conductive porous thin plate obtained by sintering a metal powder or a hydrophilic carbon powder.

Since the electromotive force of the unit cell 1 thus configured is as small as 1 V or less, a plurality of unit cells are stacked and connected in series to obtain a required electromotive force. However, the conventional polymer electrolyte fuel cell configured as described above has the following problems.

That is, when a fuel gas containing hydrogen is supplied to the fuel electrode 11 and a cell reaction is performed while an oxidizing gas containing oxygen is supplied to the oxidizing electrode 12, the oxidizing electrode 12 is produced as a by-product of the cell reaction. Water is generated on the side. This water is called product water. If this generated water is present in a large amount, it will hinder the supply of the oxidizing gas. Therefore, it is necessary to promptly remove generated water to the outside. The generated water easily moves to the oxidizing gas supply groove 16. For this reason, a method is generally adopted in which an oxidizing gas is excessively supplied and discharged by an unreacted oxidizing gas. In this method, the flow rate of the oxidizing gas and the flow rate of the excess oxidizing gas are important parameters. That is, the higher the flow rate, the more the generated water can be discharged.

However, in the conventional polymer electrolyte fuel cell, a square region is set in the center of the oxidant electrode side current collector 14 formed in a square, and the oxidant gas supply groove 16 is formed in the square region. Are provided in parallel, it is difficult to increase the flow rate of the oxidizing gas, and it is difficult to extend the life of the battery.

The flow rate of the oxidizing gas can be increased by reducing the cross-sectional area of each oxidizing gas supply groove 16, that is, the depth and width of the groove. It is difficult to realize in terms of accuracy.

In the conventional polymer electrolyte fuel cell, the fuel electrode 11 and the oxidant electrode 12 are formed to have the same dimensions and the same area. Therefore, the edge of the region of the fuel electrode 11 that contacts the polymer electrolyte membrane 10 and the oxidizer electrode 12
The edge portion of the region in contact with the polymer electrolyte membrane 10 overlaps with the polymer electrolyte membrane 10 interposed therebetween, and the membrane electrode assembly including the polymer electrolyte membrane 10, the fuel electrode 11, and the oxidant electrode 12 is pressed. During molding, pressure concentrates on the edge portion, and the portion of the polymer electrolyte membrane 10 that is in contact with the edge portion may be pushed from both sides and may be damaged. Further, the portion of the polymer electrolyte membrane 10 sandwiched between the two edge portions is always in a state of being subjected to mechanical stress due to the tightening of the cell during power generation. There is also a possibility that the portion between the two edge portions 10 is deteriorated and damaged.

In a conventional polymer electrolyte fuel cell, a humidified water permeable plate 19 obtained by sintering a metal powder or a carbon powder is used. In such a sintered body, the porous structure tends to vary depending on the sintering conditions. Further, it is difficult to control the uniform pore size and pore volume during sintering. For this reason, even in the same humidified water permeable plate 19, the hole diameter and the pore volume of each part vary, and further, the hole diameter and the pore volume of each humidified water permeable plate 19 vary. Due to such variations, the humidification water supplied to the polymer electrolyte membrane 10 becomes non-uniform, and the battery performance becomes unstable.

Furthermore, a thin cell having a high mechanical strength is required to make the cell compact, but a conventional manufacturing method of sintering a powder requires a thickness of about 1 mm. In addition, since it is a porous body of metal or carbon,
If the thickness is reduced, the mechanical strength is lost. As a result, a conventional humidified water permeable plate cannot be made thin and has high mechanical strength, and a compact cell cannot be realized.

[0018]

As described above, in the conventional solid polymer fuel cell, it is difficult to quickly discharge generated water, and large mechanical stress is easily applied to the polymer electrolyte membrane. In addition, there is a problem that the life of the battery is short because water cannot be satisfactorily supplied to the polymer electrolyte membrane. Accordingly, an object of the present invention is to provide a compact polymer electrolyte fuel cell which can significantly improve the life and is compact.

[0019]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a polymer electrolyte membrane, a fuel electrode disposed so as to sandwich the polymer electrolyte membrane, and an oxidizer. An anode, a fuel electrode side current collector disposed in contact with the back surface of the fuel electrode, an oxidant electrode side current collector disposed in contact with the back surface of the oxidant electrode, and a fuel electrode side current collector. A plurality of fuel supply grooves formed on a surface in contact with the fuel electrode for distributing fuel gas to the fuel electrode; and a plurality of fuel supply grooves formed on a surface of the oxidant electrode side current collector contacting the oxidant electrode. In a polymer electrolyte fuel cell including a unit cell including a plurality of oxidant supply grooves for distributing and supplying an oxidant gas to the oxidant electrode,
The plurality of oxidant supply grooves guide the oxidant gas along a long side of the rectangle over a substantially rectangular area within a surface of the oxidant electrode side current collector contacting the oxidant electrode. It is characterized by being provided in order to provide.

According to the first aspect of the present invention, the plurality of fuel supply grooves have a length of the rectangular shape in a region of the fuel electrode side current collector in contact with the fuel electrode and opposed to the rectangular region. It may be provided to guide the fuel gas along the sides.

Further, in the invention according to claim 1, an internal manifold for supplying the fuel gas and the oxidizing gas to the unit cell is provided outside a rectangular area on a short side of the rectangular area. It is even better if it is done.

According to a fourth aspect of the present invention, there is provided a fuel cell comprising: a polymer electrolyte membrane; a fuel electrode and an oxidizer electrode arranged so as to sandwich the polymer electrolyte membrane; A fuel electrode side current collector disposed in contact with the back surface of the electrode, an oxidant electrode side current collector disposed in contact with the back surface of the oxidant electrode, and contacting the fuel electrode of the fuel electrode side current collector A plurality of fuel supply grooves formed on the surface and distributing and supplying the fuel gas to the fuel electrode; and an oxidant formed on the surface of the oxidant electrode-side current collector contacting the oxidant electrode and providing the oxidant with the oxidant electrode. In a polymer electrolyte fuel cell provided with a unit cell including a plurality of oxidant supply grooves for distributing and supplying gas, in a region where the fuel electrode and the oxidant electrode are in contact with the respective polymer electrolyte membranes, The edge part has a shape that does not polymerize with the above polymer electrolyte membrane in between. It is characterized in that have been made.

In the invention according to claim 4, the fuel electrode and the oxidant electrode may have different areas in contact with the polymer electrolyte membrane. Further, in the invention according to claim 4, the fuel electrode and the oxidant electrode are each formed with a convex portion that forms a region in contact with the polymer electrolyte membrane, and the convex portion surrounds these convex portions. A frame-shaped reinforcing sheet formed to have substantially the same thickness as the height of the frame may be mounted. The frame-shaped reinforcing sheet may be formed of the same material as the polymer electrolyte membrane.

In order to achieve the above object, in the invention according to claim 8, a polymer electrolyte membrane, a fuel electrode and an oxidant electrode arranged so as to sandwich the polymer electrolyte membrane, A fuel electrode side current collector disposed in contact with the back surface of the electrode, an oxidant electrode side current collector disposed in contact with the back surface of the oxidant electrode, and contacting the fuel electrode of the fuel electrode side current collector A plurality of fuel supply grooves formed on the surface and distributing and supplying the fuel gas to the fuel electrode; and an oxidant formed on the surface of the oxidant electrode-side current collector contacting the oxidant electrode and providing the oxidant with the oxidant electrode. A plurality of oxidant supply grooves for distributing and supplying gas, a cooling plate provided on the back side of the anode-side current collector for guiding cooling water, and a gap between the cooling plate and the anode-side current collector. And the amount of water that is guided by the cooling plate and transfers to the fuel electrode side current collector. In the solid polymer fuel cell comprising a unit cell including a humidifying water permeation plate Gosuru, the humidifying water permeation plate is characterized in that it is formed of a non-sintered electrically conductive member.

[0025] In the invention according to claim 8, the humidified water permeable plate may be formed of a thin plate of a fluororesin material having a porous structure containing a conductive material, or holes having different sizes may be formed. It may be formed of a flat plate.

According to the first aspect of the present invention, the plurality of oxidant supply grooves are formed on the surface of the oxidant electrode-side current collector contacting the oxidant electrode.
Since the oxidant gas is provided to guide the oxidant gas along the long side of the rectangle over the substantially rectangular area, the depth and width of each oxidant supply groove are not reduced, that is, the production becomes difficult. Without increasing the flow rate of the oxidizing gas, the generated water can be satisfactorily eliminated.

That is, consider now the area of the fuel electrode (oxidizer electrode). As described above, the area of the electrode is determined by the current density, and it is assumed that 100 cm ^{2 is} required. In a conventional polymer electrolyte fuel cell, a square electrode is used, so that one side is 10 cm. On the other hand, in the invention according to claim 1, the plurality of oxidant supply grooves are provided over a substantially rectangular area on the surface of the oxidant electrode side current collector that contacts the oxidant electrode. It is not necessary to form the electrodes square. For example, a rectangular shape having a short side of 7 cm and a long side of 14.3 cm may be formed. In the invention according to claim 1, the oxidant supply groove is provided so as to guide the oxidant gas along the long side of the rectangle. Therefore, when the groove depth, the groove width, and the arrangement pitch are the same, the number of grooves in the invention according to claim 1 is smaller than that in the related art. Assuming that the supply pressure of the oxidant gas is constant, the flow rate of the oxidant gas flowing through the oxidant supply groove can be increased by the small number of the oxidant supply grooves. Therefore, generated water can be favorably eliminated.

The fact that the electrodes can be formed in a rectangular shape in this way means that the unit cell can also be formed in a rectangular shape, and the cross-sectional area orthogonal to the stacking direction of the fuel cell stack can also be formed in a rectangular shape. In other words, the fuel cell stack can be formed in a nearly flat shape with the required electrode area secured, so that the fuel cell stack can be applied to an object having only a low installation space such as an electric vehicle. It becomes possible.

In the invention according to claim 4, the fuel electrode and the oxidizer electrode are formed such that the edge portions of the regions of the fuel electrode and the oxidizer electrode which come into contact with the polymer electrolyte membrane do not polymerize with the polymer electrolyte membrane interposed therebetween. ing. Therefore, there is no portion sandwiched between both edge portions in the polymer electrolyte membrane. For this reason, it is possible to prevent the polymer electrolyte membrane from being damaged due to the presence of the above-mentioned edge portion not only when press-molding the membrane electrode assembly but also when tightening the cell during power generation.

In the invention according to claim 8, the humidified water permeable plate is formed of a conductive non-sintering member, for example, a thin plate of a porous fluororesin material containing a conductive material or a flat plate having pores formed therein. Therefore, it is extremely easy to control the pore size and pore volume. Therefore, it is possible to uniformly supply the humidified water to the polymer electrolyte membrane.

[0031]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a polymer electrolyte fuel cell according to an embodiment of the present invention, in which four solid polymer fuel cells 41 are connected in series to constitute a power source for an electric vehicle. It is shown.

As shown in FIG. 2, each of the polymer electrolyte fuel cells 41 has a plurality of unit cells 42 stacked, and conductive plates 43a and 43b, insulating plates 44a and 44b,
The end plates 45a, 45b are applied to each other, and in this state, the four corner positions of the end plates 45a, 45b are tightened with an insulating rod 46 to be integrated.

Each of the polymer electrolyte fuel cells 41 thus configured has a rectangular cross section orthogonal to the stacking direction. Then, the four solid polymer fuel cells 41
Are arranged side by side in a direction orthogonal to the direction in which the unit cells 42 are stacked, with the short sides thereof adjacent to each other in the cross section, and the boss bar 47 projecting from the conductive plates 43a and 43b is connected to the lead wire 48. To electrically connect adjacent laminates in series. Thus, the polymer electrolyte fuel cell 4
By arranging 1, the total height of the space for installing the power supply can be reduced, and the power supply can be installed in a low space such as under the floor of an automobile.

Each of the polymer electrolyte fuel cells 41 has a fuel gas supply manifold 49a for supplying and discharging a fuel gas, an oxidizing gas, and cooling water necessary for power generation, and a fuel gas. A discharge manifold 49b, a water supply manifold 50a, a drainage manifold 50b, an oxidizing gas supply manifold 51a, and an oxidizing gas discharge manifold 51b are formed in the stacking direction. In this example, the corresponding manifolds of adjacent polymer electrolyte fuel cells 41 are connected in series. Of course, they can be supplied in parallel.

FIG. 3 is an exploded perspective view of the unit cell 42. The unit cell 42 includes a polymer electrolyte membrane 60 formed of a material similar to a known one. The polymer electrolyte membrane 60 has a thickness of, for example, about 0.18 mm, and has a smaller area on both sides than the polymer electrolyte membrane and a rectangle (for example, short side) such that the short side is located on the side where the manifold is formed. 10cm, long side 20cm, electrode area 200cm
^The fuel electrode 61 and the oxidant electrode 62 formed in ² ) are arranged in contact with each other. The fuel electrode 61 and the oxidizer electrode 62 are formed by coating a surface of a carbon porous body having a thickness of, for example, 0.4 mm with carbon particles containing platinum.

As shown in FIGS. 6 and 7, the fuel electrode 61 is formed with a convex portion 63 for defining a rectangular area (area) in contact with the polymer electrolyte membrane 60. Similarly, as shown in FIGS. 6 and 7, the oxidant electrode 62 is also formed with a convex portion 64 that defines a rectangular region that contacts the polymer electrolyte membrane 60. The area of the convex portion 64 is different from the area of the convex portion 63, and is set to be large here. That is, the edge portion A of the convex portion 63 and the edge portion B of the convex portion 64 have an area relationship such that they do not overlap in the stacking direction with the polymer electrolyte membrane 60 interposed therebetween. Specifically, the edge portion B is 2
The area relationship is located on the outer side of about 5 mm. And
A fluororesin sheet or a sheet of the same material as the polymer electrolyte membrane 60 and having a thickness substantially the same as the height of the protrusions 63 so as to surround the protrusions 63 formed on the fuel electrode 61. A frame-shaped reinforcing sheet 65 formed in a shape is mounted. Similarly, a frame-shaped reinforcing sheet 65 formed in a similar sheet shape is mounted around the convex portion 64 formed on the oxidant electrode 62. Further, on the outer peripheral portions of the fuel electrode 61 and the oxidant electrode 62, sealing materials 67 and 68 formed in a frame shape with an insulating sheet made of fluoro rubber or the like having substantially the same thickness as these outer peripheral portions are arranged. .

On the back side of the fuel electrode 61, that is, on the lower surface side of the fuel electrode 61 in FIGS. 3 and 6, a fuel electrode side current collector plate having a function of supplying fuel gas to the fuel electrode 61 and a function of collecting power. 69
Are arranged in contact. The fuel electrode side current collector plate 69 is formed of a hydrophilic carbon porous plate. As shown in FIGS. 5 and 6, a fuel supply groove 70 for supplying a fuel gas to the fuel electrode 61 is formed in a contact surface of the fuel electrode side current collector plate 69 with the fuel electrode 61. A plurality of regions are formed in a rectangular region C having a smaller area and extending in a direction along the long side of the fuel electrode 61. For example, 50 fuel supply grooves 70 are provided with a width of 1 mm, a depth of 0.5 mm, a length of 20 cm, and a pitch of 2 mm. Similarly, on the back side of the oxidant electrode 62, that is, on the upper side in FIGS. 3 and 6 of the oxidant electrode 62, an oxidant that exhibits a function of supplying an oxidant gas to the oxidant electrode 62 and a function of collecting electricity. The pole-side current collecting plate 71 is arranged in contact. The oxidant electrode side current collector 71 is formed of a dense carbon plate. As shown in FIGS. 4 and 6, an oxidant supply groove 72 for supplying an oxidant gas to the oxidant electrode 62 is provided in a contact surface of the oxidant electrode-side current collector plate 71 with the oxidant electrode 62. A plurality of regions are formed in a rectangular region D smaller than the area of the oxidant electrode 62 so as to extend in a direction along the long side of the oxidant electrode 62. The oxidant supply groove 72 also has a width of, for example, 1 mm, a depth of 0.5 mm, a length of 20 cm, and a pitch of 2 mm.
Book is provided. FIG. 4 shows an oxidant electrode side current collector 71.
Are shown as viewed from below in FIG.

The humidified water permeable plate 73 is disposed in contact with the lower surface side of the fuel electrode side current collector plate 69 in FIGS. 3 and 6. A cooling plate 74 is arranged in contact. The humidified water permeable plate 73 has a hole diameter of 10 μm in a non-sintered plate having conductivity, for example, as shown in FIG.
A thin plate 77 in which 30% of carbon is mixed in a porous fluororesin-based sheet having a pore diameter of 10 μm and a pore volume of 70% is integrated on both sides of a stainless steel plate 76 having several hundred pores 75 having a diameter of m. It is formed with a thickness of 0.16 mm.

The cooling plate 74 is formed of a dense carbon plate or a metal plate. Humidifying water transmission plate 73 of cooling plate 74
A guide groove 7 for guiding cooling water
8 are formed in a region facing the region where the fuel gas supply groove 70 is provided, in parallel with the fuel gas supply groove 70.

Polymer electrolyte membrane 60, frame-shaped reinforcing sheet 6
5, 66, sealing materials 67, 68, fuel electrode side current collector 69,
Oxidant electrode side current collector 71, humidification water permeable plate 73, cooling plate 74
The fuel gas supply manifold 49 is located on both short sides (on the short sides of the rectangular areas C and D and outside the rectangular area).
a and the holes 80 and 81 forming the fuel gas discharge manifold 49b, the holes 82 and 83 forming the water supply manifold 50a and the drainage manifold 50b, and the holes 84 and 85 forming the oxidizing gas supply manifold 51a and the oxidizing gas discharge manifold 51b. Are formed so as to communicate with each other in the stacking direction.

The fuel gas supply groove 70 provided on the fuel electrode side current collector 69 communicates with holes 80 and 81 for supplying / discharging the fuel gas, and is provided on the oxidant electrode side current collector 71. The oxidant supply groove 72 communicates with holes 84 and 85 for supplying / discharging the oxidant gas, and the guide groove 78 provided on the cooling plate 74 communicates with holes 82 and 83 for supplying / discharging the cooling water. I have.

As described above, in the polymer electrolyte fuel cell 41 according to this example, the oxidizer electrode 62 of the oxidizer electrode side current collector 71
Since the plurality of oxidant supply grooves 72 for guiding the oxidant gas along the long side of the rectangle are provided in the substantially rectangular region D of the surface in contact with the groove, the depth and width of each oxidant supply groove can be reduced. Without increasing the flow rate of the oxidant gas,
As a result, generated water generated at the oxidant electrode 62 can be favorably eliminated.

That is, in the case of this example, the oxidizer electrode 6
2 as short side 10cm, long side 20cm, electrode area 200cm ²
And 50 oxidant supply grooves 72 are provided with a width of 1 mm, a depth of 0.5 mm, a length of 20 cm, and a pitch of 2 mm. Now, assuming that the current density is 0.4 A / cm ² , the air utilization rate is 40%, and the oxidant gas (air) supply pressure is 1 atm, the flow rate of the oxidant gas flowing through each oxidant supply groove 72 is 300 cm / sec. On the other hand, the same electrode area 200cm
^When oxidant supply grooves of the same groove width, groove depth and arrangement pitch are provided using a square electrode (side length 14 cm) in ² , and oxidant gas is supplied under the same conditions, each oxidant supply groove The flow rate of the oxidizing gas flowing through is 210 cm / sec. As described above, in this example, the flow rate of the oxidizing gas can be increased by 1.5 times while maintaining the same electrode area. Therefore,
The generated water can be discharged well. As a result, the generated water does not stay in the oxidant electrode 62 to hinder the supply of the oxidant gas, and the battery performance can be maintained for a long time.

The fact that the oxidizer electrode 62 and the fuel electrode 61 can be formed in a rectangular shape in this way means that the planar shape of the unit cell 42 can also be formed in a rectangular shape, and the cross-sectional area orthogonal to the stacking direction of the fuel cell stack is also reduced. It can be formed into a rectangle. In other words, the fuel cell stack can be formed in a nearly flat shape with the required electrode area secured, so that the fuel cell stack can cope with an object having only a low installation space, such as an electric vehicle. It becomes possible.

Also, in the above example, the fuel electrode 61 and the oxidizer electrode 62 are formed so that the edge portions A and B of the areas in contact with the polymer electrolyte membrane 60 do not polymerize with the polymer electrolyte membrane 60 interposed therebetween. An oxidant electrode 62 is formed. Therefore, both edge portions A and B are provided on the polymer electrolyte membrane 60.
Therefore, there is no portion to be sandwiched. For this reason, not only when the membrane electrode assembly is press-molded but also when the cell is tightened during power generation, the above-described edge portions A,
It is possible to prevent the polymer electrolyte membrane 60 from being damaged by the presence of B.

FIG. 9 shows the results of a power generation test for comparing performance using the unit cell of this example and the unit cell of the conventional example. In the unit cell of the conventional example, about 2
Although the cell voltage dropped to 0.2 V in 000 hours, the cell voltage of the unit cell according to this example did not decrease even after more than 4000 hours.

Further, a power generation test was performed by a screen printing machine using a fuel electrode and an oxidizer electrode manufactured using a screen pattern in which the peripheral portion of the electrode was thinned by the thickness of the frame-shaped reinforcing sheets 65 and 66. However, a result equivalent to the characteristic shown in FIG. 9 was obtained. Further, in the above example, the humidified water permeable plate 73 is formed of a conductive non-sintered member, a thin plate of a fluorine-based resin material having a porous structure containing a conductive material, and a metal plate having pores. It is very easy to control the pore volume, and as a result, humidified water can be uniformly supplied to the polymer electrolyte membrane 60.

That is, FIG. 10 shows a power generation test result of a 5-cell stacked battery in which the unit cells according to the above example are stacked in 5 stages, and FIG. 11 shows a 5-cell stack in which 5 unit cells in the conventional example are stacked. The results of the power generation test of the laminated battery are shown.

In a conventional laminated battery using unit cells,
Immediately after the start of power generation, the cell voltage fluctuated for each cell,
Even after 00 hours, the cell voltage remained variable, and further decreased by an average of 0.12 V. However, in the stacked battery using the unit cells according to this example, the cell voltages were uniform immediately after the start of power generation, and no variation or decrease in the cell voltage was observed even after 5000 hours. Further, as the humidified water permeable plate 73, a 30% composite of a 100-mesh, fluororesin-based sheet having a mesh structure of 85 μm in diameter and carbon, and a central 10 cm × 10 cm area are etched by 1%.
When the above-described power generation test was performed using a stainless steel plate provided with 300 0 μm pores, the same results were obtained in both cases. These are due to the fact that humidified water could be uniformly supplied to the polymer electrolyte membrane 60.

The present invention is not limited to the above-described example, but can be variously modified. That is, in the above example, the size of the fuel electrode 61 and the size of the oxidant electrode 62 are the same, but they may be different as shown in FIG.

As shown in FIG. 13, the area of the polymer electrolyte membrane 60 is made the same as the size of the fuel electrode 61 or the oxidizer electrode 62, and a frame formed of a fluororesin sheet or the like is formed on the outside thereof. Material 91 may be arranged. Further, as shown in FIG.
A configuration in which only the size of 2 is changed may be used.

The configuration of the humidification water permeable plate is not limited to the above-described example. As shown in FIG. 15, a portion of the cooling plate corresponding to the region where the cooling water guide groove is provided has a mesh structure. A humidified water permeable plate 73a formed of a member 92 in which a certain fluororesin sheet and carbon are compounded, and the periphery thereof is formed of a member 93 such as a fluororesin sheet.
May be used.

Further, as shown in FIG. 16, the humidified water permeable plate 73b is formed of a stainless steel thin plate 94,
The one provided with pores 95 having different pore diameters in a portion located on the cooling water guide groove of No. 4 may be used. In this example, the length of the cooling water guide groove is divided into three, 15 μm in the 1/3 region located upstream, 10 μm in the 1/3 region located midstream, and 10 μm downstream. 5μ in 1/3 area
The diameter of the pores is reduced as going from upstream to downstream. By using the humidification water permeable plate 73b having such a configuration, it is possible to control the amount of humidification water supplied to the downstream portion where the humidification amount tends to be excessive due to the generated water. The pores can be formed in the metal plate by etching, laser processing, electric discharge processing, drilling, or the like. Further, the thickness of the humidified water permeable plate is preferably 0.5 mm or less.

[0054]

As described above, according to the present invention,
The life can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a mounting configuration of a polymer electrolyte fuel cell according to an embodiment of the present invention.

FIG. 2 is a side view of the polymer electrolyte fuel cell.

FIG. 3 is an exploded perspective view of a unit cell incorporated in the polymer electrolyte fuel cell.

FIG. 4 is a view showing one surface of an oxidant electrode-side current collecting plate incorporated in the unit cell;

FIG. 5 is a diagram showing one surface of a fuel electrode side current collector plate incorporated in the unit cell.

FIG. 6 is a longitudinal sectional view of the unit cell.

FIG. 7 is an exploded sectional view of a main part of the unit cell.

FIG. 8 is an exploded perspective view of a humidified water permeable plate incorporated in the unit cell.

FIG. 9 is a diagram showing the power generation characteristics of the unit cell in comparison with a conventional example.

FIG. 10 is a view showing power generation characteristics of the polymer electrolyte fuel cell.

FIG. 11 is a diagram showing power generation characteristics of a conventional polymer electrolyte fuel cell.

FIG. 12 is a diagram illustrating a modification of the present invention.

FIG. 13 is a view for explaining another modified example of the present invention.

FIG. 14 is a view for explaining still another modified example of the present invention.

FIG. 15 is a diagram for explaining a different modification of the present invention.

FIG. 16 is a view for explaining still another modified example of the present invention.

FIG. 17 is a longitudinal sectional view of a unit cell incorporated in a conventional polymer electrolyte fuel cell.

FIG. 18 is a view showing one surface of a fuel electrode side current collector plate incorporated in the unit cell.

[Explanation of symbols]

 41 solid polymer fuel cell 42 unit cell 49a fuel gas supply manifold 49b fuel gas discharge manifold 50a water supply manifold 50b drainage manifold 51a oxidant gas supply manifold 51b oxidant gas discharge manifold 60 polymer Electrolyte membrane 61 ... Fuel electrode 62 ... Oxidizer electrode 63, 64 ... Protrusion 65, 66 ... Frame-shaped reinforcing sheet 67, 68 ... Sealing material 69 ... Fuel electrode side current collector plate 70 ... Fuel supply groove 71 ... Oxidizer electrode side Current collector plate 72: Oxidant supply groove 73, 73a, 73b: Humidifying water permeable plate 74: Cooling plate 78: Guide groove A, B: Edge portion C, D: Rectangular area

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01M 8/10 H01M 8/10 8/24 8/24 R

Claims (11)

[Claims] 1. A fuel cell comprising: a polymer electrolyte membrane; a fuel electrode and an oxidizer electrode arranged so as to sandwich the polymer electrolyte membrane; and a fuel electrode side current collector arranged in contact with the back surface of the fuel electrode An oxidant electrode-side current collector disposed in contact with the back surface of the oxidant electrode; and a fuel gas formed on a surface of the fuel electrode-side current collector that is in contact with the fuel electrode, distributing and supplying fuel gas to the fuel electrode. And a plurality of oxidant supply grooves formed on a surface of the oxidant electrode side current collector contacting the oxidant electrode and distributing and supplying an oxidant gas to the oxidant electrode. In the polymer electrolyte fuel cell provided with the unit cells, the plurality of oxidant supply grooves extend over a substantially rectangular area in a surface of the oxidant electrode-side current collector that contacts the oxidant electrode. A solid body provided to guide the oxidizing gas along the long side of the rectangle Polymer fuel cell. 2. The fuel supply groove guides a fuel gas along a long side of the rectangle to a region facing the rectangle on a surface of the fuel electrode side current collector contacting the fuel electrode. The polymer electrolyte fuel cell according to claim 1, wherein the polymer electrolyte fuel cell is provided so as to be provided. 3. An internal manifold for supplying the fuel gas and the oxidizing gas to the unit cell is provided on a short side of the rectangular area and outside the rectangular area. The polymer electrolyte fuel cell according to claim 1. 4. A polymer electrolyte membrane, a fuel electrode and an oxidizer electrode arranged so as to sandwich the polymer electrolyte membrane therebetween, and a fuel electrode side current collector arranged in contact with the back surface of the fuel electrode An oxidant electrode-side current collector disposed in contact with the back surface of the oxidant electrode; and a fuel gas formed on a surface of the fuel electrode-side current collector that is in contact with the fuel electrode, distributing and supplying fuel gas to the fuel electrode. A plurality of fuel supply grooves, and a plurality of oxidant supply grooves formed on a surface of the oxidant electrode-side current collector that is in contact with the oxidant electrode to distribute and supply an oxidant gas to the oxidant electrode. In the polymer electrolyte fuel cell provided with the unit cell including the above, the fuel electrode and the oxidizer electrode each have a shape in which an edge portion of a region in contact with the polymer electrolyte membrane does not polymerize with the polymer electrolyte membrane interposed therebetween. Polymer fuel cell characterized by being formed in . 5. The polymer electrolyte fuel cell according to claim 4, wherein the fuel electrode and the oxidant electrode have different areas in contact with the polymer electrolyte membrane. 6. The fuel electrode and the oxidizer electrode are each formed with a convex portion that forms a region that comes into contact with the polymer electrolyte membrane, and has a height substantially equal to the height of the convex portion so as to surround the convex portion. The polymer electrolyte fuel cell according to claim 4, wherein a frame-shaped reinforcing sheet having the same thickness is mounted. 7. The polymer electrolyte fuel cell according to claim 6, wherein the frame-shaped reinforcing sheet is formed of the same material as the polymer electrolyte membrane. 8. A polymer electrolyte membrane, a fuel electrode and an oxidizer electrode arranged so as to sandwich the polymer electrolyte membrane therebetween, and a fuel electrode side current collector arranged in contact with the back surface of the fuel electrode An oxidant electrode-side current collector disposed in contact with the back surface of the oxidant electrode; and a fuel gas formed on a surface of the fuel electrode-side current collector that is in contact with the fuel electrode, distributing and supplying fuel gas to the fuel electrode. A plurality of fuel supply grooves to be formed, a plurality of oxidant supply grooves formed on a surface of the oxidant electrode-side current collector contacting the oxidant electrode, and distributing and supplying an oxidant gas to the oxidant electrode; A cooling plate provided on the back side of the anode-side current collector for guiding cooling water; and a cooling plate provided between the cooling plate and the anode-side current collector and guided by the cooling plate. Solid unit comprising a unit cell including a humidified water permeable plate for controlling the amount by which the part moves to the anode-side current collector. In the child type fuel cell, the humidification water permeation plate, a polymer electrolyte fuel cell characterized by being formed of a non-sintered electrically conductive member. 9. The polymer electrolyte fuel cell according to claim 8, wherein the humidified water permeable plate is formed of a thin plate of a porous fluororesin material containing a conductive material. 10. The polymer electrolyte fuel cell according to claim 8, wherein the humidified water permeable plate is formed of a flat plate having holes of different sizes. 11. A polymer electrolyte membrane, a fuel electrode and an oxidizer electrode disposed so as to sandwich the polymer electrolyte membrane therebetween, and a fuel electrode side current collector disposed in contact with the back surface of the fuel electrode An oxidant electrode-side current collector disposed in contact with the back surface of the oxidant electrode; and a fuel gas formed on a surface of the fuel electrode-side current collector that is in contact with the fuel electrode, distributing and supplying fuel gas to the fuel electrode. And a plurality of oxidant supply grooves formed on a surface of the oxidant electrode side current collector contacting the oxidant electrode and distributing and supplying an oxidant gas to the oxidant electrode. A solid body in which a plurality of stacked unit cells are stacked in a direction orthogonal to the stacking direction of the unit cells, and adjacent stacked units are electrically connected in series. Polymer fuel cell.