JPH0950819A - Solid polymer electrolyte fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid polymer electrolyte fuel cell in which dew drops adhering to the wall faces of flow pipeline of a separator to pass a fuel gas and an oxidizing agent gas can be removed. SOLUTION: Different from a conventional separator employed for a conventional solid polymer electrolyte fuel cell, a separator 1 is so formed as to have through holes 825A, 826A directly communicated with grooves 821A which are a partial flow pipeline to pass an oxidizing agent gas through. A plurality of the grooves 821A which the separator 1 has are connected in series one another through a groove 11A having the same cross-section shape as those of the grooves 821A to make an oxidizing agent gas 98 flow in the grooves. Moreover, though through holes 825B, 826B which the separator 1 has are communicated with grooves (not shown in the figure) to make a heat medium flow through in the same manner as a conventional fuel cell, these grooves for the flow of the heat medium are mutually connected in series from a viewpoint of the flow of the heat medium through the through hole 825B and the through hole 826B in a different manner in a conventional separator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid polymer electrolyte fuel cell, and removes water droplets adhering to the wall surface of the flow passage through the flow passage through which the fuel gas and the oxidant gas of the separator flow. The structure is improved so as to enable

[0002]

2. Description of the Related Art A fuel cell is a kind of power generator that generates direct current power by using hydrogen and oxygen, and as is well known, it is converted into electric energy as compared with other energy engines. High efficiency and low emission of carbon dioxide, nitrogen oxides and other air pollutants,
It is expected as a so-called clean energy source. Depending on the type of electrolyte used, this fuel cell may be a solid polymer electrolyte type, a phosphoric acid type, a molten carbonate type,
Various fuel cells such as a solid oxide fuel cell are known.

Among these fuel cells, solid polymer electrolyte fuel cells show a low electric resistivity when a polymer resin membrane having a proton (hydrogen ion) exchange group in the molecule is saturated with water. A fuel cell that utilizes the function of a proton conductive electrolyte. A polymer resin membrane having a proton exchange group in the molecule (hereinafter, may be abbreviated as a solid polymer electrolyte membrane or simply PE membrane) is a par.
Fluorine-based ion-exchange resin membranes represented by fluorosulfonic acid resin membranes (for example, Nafion membrane manufactured by DuPont, USA) are well known at this time, but in addition to these, hydrocarbon-based ion-exchange resin membranes and composite membranes are also known. A resin film or the like is used. These solid polymer electrolyte membranes (PE membranes) show an electric resistivity of 20 [Ω · cm] or less at room temperature when they are saturated with water, and both are membranes that function as a proton conductive electrolyte. is there.

A solid polymer electrolyte fuel cell filed by the same applicant as this type of device is disclosed in Japanese Patent Application Laid-Open No. 6-967.
It is known from Japanese Patent No. 77. The solid polymer electrolyte fuel cell of the prior art will be described below based on the content of the solid polymer electrolyte fuel cell known from Japanese Patent Laid-Open No. 6-96777. First, a unit fuel cell included in a conventional solid polymer electrolyte fuel cell will be described with reference to FIGS. 8 and 9. Here, FIG. 8 is a cross-sectional view schematically showing a main portion of a unit fuel cell included in a solid polymer electrolyte fuel cell of a conventional example in an unfolded state and seen from the upper side, and FIG. FIG. 9 is a view of the separator shown in FIG. 8 viewed from the P arrow direction in FIG. 8.

In FIGS. 8 and 9, reference numeral 8 is a unit fuel cell (hereinafter referred to as a unit cell) composed of a fuel cell 7 and separators 81 and 82 arranged so as to face each of both main surfaces thereof. It may be abbreviated). The fuel cell 7 includes a sheet-shaped solid polymer electrolyte membrane 7C, a sheet-shaped fuel electrode film (also an anode electrode) 7A, and a sheet-shaped oxidant electrode film (also a cathode electrode) 7B. It is configured. The fuel cell 7 includes a fuel gas 97, which will be described later, and an oxidizer electrode film 7A.
Receiving the supply of the oxidant gas 98 described later in B,
DC power is generated by the electrochemical reaction described later. The PE film described above is used for the solid polymer electrolyte membrane 7C. The PE film 7C has a thickness dimension of about 0.1 [mm] and an outer dimension in the plane direction larger than the outer dimension in the plane direction of the electrode films 7A and 7B. , 7B, there is an exposed surface of the PE film 7C between itself and the end of the PE film 7C. The outer surface of the fuel electrode film 7A is one side surface 7a of the fuel cell 7, and the outer surface of the oxidant electrode film 7B is the other side surface 7b of the fuel cell 7.

Both the fuel electrode film 7A and the oxidant electrode film 7B are composed of a catalyst layer containing a catalyst active material and an electrode base material. It is general that they are brought into close contact with each other by hot pressing. The electrode base material supports the catalyst layer, supplies and discharges a reaction gas (hereinafter, the fuel gas and the oxidant gas may be collectively referred to as such), and has a function as a current collector. It is also a porous sheet (for example, carbon paper is used as the material used).

When the reactant gas is supplied to the fuel electrode film 7A and the oxidant electrode film 7B, a gas phase (fuel gas) is formed at the interface between the catalyst layer provided on each of the electrode films 7A and 7B and the PE film 7C. Or oxidant gas), liquid phase (solid polymer electrolyte),
A three-phase interface of a solid phase (a catalyst of the fuel electrode film and the oxidant electrode film) is formed, and a DC power is generated by causing an electrochemical reaction. Incidentally, in many cases, the catalyst layer is formed from a fine particulate platinum catalyst and a fluororesin having water repellency, and by forming a large number of pores in the layer, It is configured to maintain efficient diffusion of the reaction gas to the three-phase interface and form a sufficiently large area of the three-phase interface.

At the three-phase interface, the following electrochemical reaction occurs. First, on the side of the fuel electrode film 7A, an electrochemical reaction according to "1 formula" occurs.

[0009]

Embedded image

On the side of the oxidant electrode film 7B, an electrochemical reaction according to "Formula 2" occurs.

[0011]

Embedded image

That is, as a result of these electrochemical reactions,
H ⁺ ions (protons) generated in the fuel electrode film 7A
Moves in the PE film 7C toward the oxidant electrode film 7B, and the electrons (e ⁻ ) move to the oxidant electrode film 7B through a load device (not shown) of the solid polymer electrolyte fuel cell. . On the other hand, in the oxidizer electrode film 7B, the oxidizer gas 98
Oxygen contained in the PE film 7C and the fuel electrode film 7A
The H ⁺ ions that have moved from the inside react with the electrons that have moved through the load device, and H ₂ O (water vapor) is generated. Thus, the solid polymer electrolyte fuel cell obtains hydrogen and oxygen to generate DC power, and thus H ₂ O (steam) as a by-product.

In many cases, the fuel cell 7 having the above-mentioned function has a thickness of about 1 mm or less, and in the fuel cell 7, the PE film 7C is composed of the fuel gas 97 and the oxidizer. It also serves as a sealing film for preventing mixing with the gas 98. Also,
The separator 81 and the separator 82 are used for the fuel cell 7
The supply of the reaction gas to the fuel cell 7, the discharge of the excess reaction gas from the fuel cell 7, the extraction of the DC power generated in the fuel cell 7 from the fuel cell 7, and the generation of the DC power. It plays a role of removing heat generated from the fuel cell 7 from the fuel cell 7. Both of the separators 81 and 82 are gas impermeable, have good thermal conductivity and good electrical conductivity, and do not pollute the produced water (for example, carbon-based materials and metallic materials). Is used.) Is manufactured into the same rectangular parallelepiped shape. Then, the separators 81 and 82 have the side surfaces 81a and 82a facing the fuel cell 7, the side surfaces 81b and 82b opposite to the side surfaces 81a and 82a, and the side surfaces 81a and 82a, respectively. And side surfaces 81c and 82c facing the electrode films 7A and 7B, which are formed by providing a step by a dimension corresponding to the thickness dimension. Further, the separator 82 will be described. The separator 82 has a pair of end faces 82d and 82e that are orthogonal to the side face 82a and the side face 82b and are parallel to each other. The separator 81 also has end faces similar to the end faces 82d and 82e. The side surface 82c of the separator 82 is brought into close contact with the side surface 7b of the fuel cell 7 and the side surface 82a thereof is brought into close contact with the exposed surface of the PE film 7C, and the side surface 81c of the separator 81 is kept close to the side surface 7a of the fuel cell 7. In addition, the side surfaces 81a thereof are closely contacted with the exposed surfaces of the PE film 7C, respectively, and the fuel cell 7 is sandwiched therebetween.

The separators 81 and 82 serve as flow passages for supplying and discharging the reaction gas to and from the fuel cell 7.
Side surface 81 which is also the surface facing the fuel cell unit 7
c, 82c, and the end faces 82d, 82
A plurality of concave grooves, which are partial flow passages through which each gas flows, are provided in a relationship orthogonal to e (in the case of the separator 82). That is, the separator 81 is an interval for allowing the fuel gas 97 to flow along the side surface 81c contacting the side surface 7a of the fuel cell 7 and discharging the excess fuel gas 97 containing unconsumed hydrogen. And a concave groove 811A provided with
The convex partition walls 812A interposed therebetween are alternately formed. The separator 82 is provided with an oxidizer gas 98 along the side surface 82c that is in contact with the side surface 7b of the fuel cell unit 7.
Through which a concave groove 821A is provided with a space for discharging excess oxidant gas 98 containing unconsumed oxygen, and a convex partition wall 822A interposed between the grooves 821A. And are formed alternately with each other.
The tops of the convex partition walls 812A and 822A are the side surfaces 81c and 8 of the separators 81 and 82, respectively.
It is formed so as to be flush with 2c. In addition, the side surfaces 81a and 82a of the separators 81 and 82 and the side surface 81c,
82c is connected to edge portions 81f and 82f having dimensions commensurate with the dimensions of the peripheral portions of the electrode films 7A and 7B.

The separator 82 will be described as a representative example. Each groove 8 formed in the separator 82 will be described.
At both ends of 21A, these grooves 821A are in parallel with each other and communicate with the manifolds 823A and 823A. Each of the manifolds 823A is formed in a concave groove shape, and has a larger flow area of the fuel gas 97 than the flow area of the groove 821A. At the end portions of the manifolds 823A, 823A, a pair of through holes 825A, 82 opening in the side surface 82b.
6A are formed. The through hole 825A is an inflow port for the oxidant gas 98 in the separator 82, and
26A is an outlet of the oxidant gas 98 in the separator 82. By connecting the side surface 82a and the side surface 82b, as shown in FIG.
As shown in the inside, for the through holes 825A and 826A,
The through hole 817 is formed in the portion where the mutual positional relationship is established.
A and 818A are formed. This through hole 817A,
818A is a through hole for allowing the fuel gas 97 in the separator 82 to flow therethrough.

The oxidant gas 98 flowing through the inside of the separator 82 thus constructed flows into the separator 82 through the through hole 825A, and one manifold 823A.
Through a plurality of grooves 821A to flow through, and are merged in the other manifold 823A to form a through hole 826.
It will be leaked from A. During this time, each groove 8
Since the manifolds 823A and 823A having the above-described configurations are formed on the inflow side and the outflow side of the oxidant gas 98 of 21A, the oxidant gas 98 is evenly distributed to the respective grooves 821A. It will be flowed.

Although not shown, the separator 81 also has through holes 825A and 826A in the separator 82.
And groove 811A similar to through holes 817A and 818A
A through hole serving as an inlet and an outlet of the fuel gas 97 communicating with the fuel gas 97, and a through hole for allowing the oxidant gas 98 to flow at a portion having a positional relationship of being crossed with the through hole. ing. The shapes and dimensions of the grooves 811A and 821A formed in the separators 81 and 82 are such that the pressure drop value Δp _s generated when the reaction gas is passed through the grooves 811A and 821A is 811A, 821
Each of A has a water holding head p _k (JP-A-6-
As disclosed in Japanese Patent No. 96777, see the following "Formula 7". ) Is set to be larger than the value.

Further, the separators 81, 82 are provided with grooves for allowing the heat medium 99 to flow therethrough as a heat exchanger for removing the heat generated in the fuel cells 7 from the fuel cells 7. That is, the side surface 8 of the separator 82 is
A concave groove 821B that allows the heat medium 99 to flow therethrough is formed on the 2b side, and the heat medium 9 is also formed on the side surface 81b of the separator 81.
A groove 811B having a concave shape that allows the gas to flow therethrough is formed. Through holes 825B and 826 formed in the separator 82
B is a through hole that allows the heat medium 99 to flow therethrough, and is a groove 821B.
Is communicated to.

Further, 73 is a gas seal body (for example, an O-ring) made of an elastic material which has a function of preventing the reaction gas flowing in the gas flow passage from leaking out of the gas flow passage. It is). The gas seal body 73 is housed and mounted in concave grooves 819 and 829 formed in the peripheral portions of the respective separators 81 and 82. Further, on the side surface 81b of the separator 81 and the side surface 82b of the separator 82, concave grooves 818B and 828B are formed surrounding the grooves 811B and 821B, respectively. These concave grooves are for accommodating a seal body (for example, an O-ring) made of an elastic material for preventing the heat medium 99 from leaking out.

By the way, as is well known, the voltage generated by one fuel battery cell 7 is as low as about 1 [V] or less. For this reason, the unit cells 8 having the above-described structure are stacked in plural (often several tens to several hundreds) so that the generated voltages of the fuel cells 7 are connected in series. It is generally constructed as a laminated body of unit cells and used for practical purposes by increasing the voltage. Next, a conventional example of a solid polymer electrolyte fuel cell which is a laminated body of the unit cells will be described.

FIG. 10 is a schematic view of a main part schematically showing a conventional solid polymer electrolyte fuel cell, in which (a) is a side view thereof and (b) is a top view thereof. , Fig. 11
FIG. 11 is a detailed sectional view of a Q portion in FIG. 10. FIG.
11, the same parts as those of the unit cell shown in FIGS. 8 and 9 are designated by the same reference numerals, and the description thereof will be omitted. FIG.
0, in FIG. 11, about the code | symbol attached in FIG. 8, only the typical code | symbol was described. 9 in FIGS. 10 and 11.
Is a solid polymer electrolyte mainly composed of a laminated body of the unit cells 8 constituted by stacking a plurality of unit cells 8 (in FIG. 10, the number of unit cells 8 is eight). Type fuel cell (hereinafter sometimes referred to as a stack).

The stack 9 has collector plates 91, 91 made of a conductive material such as copper for extracting DC power generated in the unit cell 8 from both ends of the stack of unit cells 8.
An electrical insulating plate 92, 92 made of an electrical insulating material for electrically insulating the unit cell 8 and the current collecting plate 91 from the structure, and an iron material and the like arranged on both outer side surfaces of both the electrical insulating plates 92. The pressure plates 93 and 94 made of metal are sequentially laminated and configured. Then, the pressurizing plates 93, 94 are given an appropriate pressing force from the respective outer surface sides by a plurality of tightening bolts 95.

In FIG. 11, 825A is a groove 821A.
Is a through hole serving as an inflow port for the oxidant gas 98 communicating with the oxidant gas 98. It is a concave groove for accommodating a gas seal body (for example, an O-ring) 982 made of an elastic material, which has a role of preventing leakage of the gas. As shown in FIG. 11, in the current collector plate 91, the electrical insulating plate 92, and the pressure plate 93, the through hole 91 is formed at a portion that matches the through hole 825A.
1, 921, and a through hole 931 with a female thread for a pipe are formed respectively. Although not shown in the drawings, the current collector plate 91, the electrical insulating plate 92, and the pressure plate 93 are not shown.
The through holes 911 and 92 are provided at the portions that are matched with the through holes communicating with A (the through holes are the same as the through holes 825A).
Through hole similar to 1 and through hole 93 with female thread for pipe
Through holes 932 similar to those of No. 1 are formed. Further, through-holes 941 and 942 similar to the through-holes 931 and 932 are formed in the pressure plate 94, respectively, and through-holes are also formed in the electrical insulating plate 92 and the current collector plate 91 adjacent to the pressure plate 94. Through-holes similar to the through-holes 921 and 911 are formed in the portions that match with 941 and 942, respectively.

As a result, when stacking a plurality of unit cells 8, the grooves 821A of all the unit cells 8 are connected to each other with respect to the gas passage for the oxidizing gas 98. This also applies to the groove 811A for the fuel gas 97. Then, the fuel gas 9 is put in the through hole 941 on the side surface which is the outer surface of the stack 9 of the pressure plate 94.
7 is supplied, and excess oxidant gas 98 is discharged from the through hole 942. Further, the oxidant gas 98 is provided in the through hole 931 on the side surface which is the outer surface of the stack 9 of the pressure plate 93.
Is supplied, and the surplus fuel gas 9 is supplied from the through hole 932.
7 is discharged. Then, each through hole is surrounded by the opening portion of the through hole 911 on one side surface of the current collector plate 91 and the opening portion on the one side surface side of the through hole 921 of the electric insulating plate 92. Recessed grooves 912 and 922 are formed. A gas seal body 982 is attached to these grooves 827A, 912, 922 (see FIG. 11).

In the stack 9, when stacking a plurality of unit cells 8, the grooves 811B and 821B of all the unit cells 8 are arranged in parallel with each other with respect to the flow of the heat medium 99. , The inflow part (the through hole 825B, etc.) of the heat medium 99 and the outflow part (the through hole 8).
26B and the like. ) Comrades are connected to each other by communicating with each other. Therefore, the inflow portions of the heating medium 99 in the grooves 811B and 821B of all the unit cells 8 are continuously connected with respect to the flow path of the heating medium 99. Similarly, the outflow portions of the heat medium 99 in all the grooves 811B and 821B are continuously connected to the flow path of the heat medium 99. A through hole (not shown) communicating with the inflow portion of the heat medium 99 is formed in the pressure plate 94 and the electric insulating plate 92 and the current collector plate 91 adjacent to the pressure plate 94. Also,
Pressure plate 93 and electrical insulating plate 9 adjacent to the pressure plate 93
2. In the current collector plate 91, a through hole (not shown) communicating with the outflow portion of the heat medium 99 is formed. Among these through holes, the pipe connecting bodies 991 for the heating medium 99 are mounted in the through holes formed in the pressure plates 93 and 94, respectively.

The tightening bolts 95 are hexagonal bolts or the like mounted over the pressure plates 93 and 94, and each tightening bolt 95 has a hexagonal nut or the like fitted thereto and a stable pressurizing force. The unit cells 8 are pressed in the stacking direction in cooperation with a disc spring for giving, a gas pressure type pressurizing body and the like. The pressing force applied by the tightening bolts 95 to the unit cells 8 is 5 per the apparent surface area of the fuel cell unit 7.
[Kg / cm ² ] Generally, it is inside or outside.

In the stack 9 configured as described above, the PE membrane 7C used in the fuel cell 7 is a membrane that functions as a good proton conductive electrolyte by being saturated with water as described above. When the water content decreases due to drying, the electric resistance value increases, so that the power generation performance of the stack 9 decreases. In order to prevent such occurrences, the reaction gas supplied to the fuel cell unit 7 is humidified to an appropriate humidity value, and further heated to a temperature corresponding to the operating temperature of the stack 9 described later, so that the stack 9 Is being supplied to.

By the way, the temperature of the PE film 7C,
The temperature of the unit cell 8 is 50 to 1 in order to smoothly evaporate the water generated in the fuel cell unit 7 during the power generation operation.
It is generally used at a temperature of about 00 [° C]. In addition, the above-mentioned “1 set”, “2” performed in the fuel cell 7
The electrochemical reaction described in “Formula” is an exothermic reaction. Therefore, when power is generated by the electrochemical reaction in the fuel cell unit 7 according to "1 type" and "2 type", it is unavoidable that heat of a value almost equal to the generated DC power value is generated. is there. In order to maintain the temperature of the unit cell 8 at about 50 to 100 [° C.], it is necessary to remove the heat due to this loss from the fuel cell unit 7.

The stack 9 which is still cold at the start is
The amount of heat generated by the exothermic reaction is removed from the stack 9 during power generation operation in order to heat it to a temperature of 0 to 100 [° C] or to maintain the operating temperature at a temperature of 50 to 100 [° C]. What is done is, for example, the main role of the heat medium 99 which is city water. In the unit cell 8, for example, 50 to 10
The heat medium 99 adjusted to a temperature of about 0 [° C.] flows through the grooves 811B and 821B formed in the separators 81 and 82, so that the fuel cell 7 is operated while being maintained at its appropriate temperature. It is. In this case, the heat medium 99 flows into the stack 9 from the pipe connection body 991 attached to the pressure plate 94 and flows out of the stack 9 from the pipe connection body 991 attached to the pressure plate 93. ing.

As the separator, there is also known one in which a groove 811A for allowing the fuel gas 97 to flow therethrough is formed on one side surface and a groove 821A for allowing the oxidant gas 98 to flow therethrough on the other side surface. ing. Furthermore,
As the unit cell, a separator not provided with a groove for allowing the heat medium 99 as the heat exchange body to flow therethrough is used, and instead, a dedicated cooling body as the heat exchange body is inserted in the stacked body of the unit cells. It is also known to do the stack. In this case, the cooling medium is generally supplied with the heat medium 99 via an appropriate pipe.

As a unit fuel cell (unit cell) included in the solid polymer electrolyte fuel cell of the conventional example, a unit cell having the structure shown in FIG. 12 is also known. Here, FIG. 12 is a cross-sectional view schematically showing a main part of a unit fuel cell of a different case included in the solid polymer electrolyte fuel cell of the conventional example in an expanded state and seen from the upper side thereof. In FIG. 12, the same parts as those in the unit fuel cell according to the conventional example shown in FIGS. 8 and 9 are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 12, 8A is a separator 81, which is different from the unit cell 8 according to the conventional example shown in FIGS.
It is a unit cell in which separators 83 and 84 are used instead of 82. The separator 84 is composed of a separator main body portion 84A and a reaction gas flow portion 84B with respect to the separator 82 of the unit cell 8. The reaction gas flow portion 84B is a material that is permeable to gas, has good thermal conductivity and good electrical conductivity, and that does not pollute the produced water (for example, porous carbon). It is manufactured by using the material of the system and the metal material.). Then, in the reaction gas flow portion 84B, a plurality of grooves 821A and partition walls 8 that are the same as those of the separator 82 are provided.
22A and manifolds 823A and 823A are formed, and the reaction gas flow portion 84B is connected to the separator body portion 8
By being incorporated in 4A, the separator 84 has all the functions of the separator 82. Separator 8
3 also includes a separator body 83A and a reaction gas passage 83B having the same structure as the reaction gas passage 84B with respect to the separator 81 of the unit cell 8. By incorporating it into the separator body 83A, all the functions of the separator 81 are provided.

In the separators 83 and 84, the reaction gas flows through the grooves 811A and 821A and at the same time passes through the reaction gas flow portions 83B and 84B having gas permeability.
It is supplied to the fuel electrode film 7A and the oxidant electrode film 7B. At that time, the separators 83 and 84 are connected to the electrode films 7A and 7B.
Side surfaces 81c and 82c, which are surfaces that come into contact with the outer surface of
Unlike the case where the separators 81 and 82 contact only at the tops of the partition walls 812A and 822A, it is advantageous to contact all the side surfaces of the electrode films 7A and 7B. This makes it possible to reduce the stress value generated in the electrode films 7A and 7B as compared with the case where the separators 81 and 82 in which local stress is generated are used. The unit cell 8A is also used by being incorporated in the stack 9 as in the case of the unit cell 8.

In the stack 9 having the above-mentioned structure, steam is produced as a by-product of power generation as described above.
This water vapor is contained in the reaction gas and is discharged from the stack 9 together with the excess reaction gas. As a result, the reaction gas in the unit cells 8 and 8A has a distribution in which the amount of water vapor contained along the flow direction of the reaction gas increases toward the downstream side. Therefore, in the case where the reaction gas is humidified to near saturation and supplied to the stack 9, the reaction gas flowing through the grooves 811A and 821A is at the reaction gas outlet (such as the through hole 826A). In the vicinity, it is possible that supersaturated water vapor may be contained. Then, in this case, water vapor corresponding to supersaturation is condensed in the reaction gas near the outlet, and liquid condensed water is present. The presence of this condensed water obstructs the flow of the reaction gas, and the supply amount of the reaction gas to the fuel cell 7 becomes insufficient, resulting in a decrease in the power generation capacity of the fuel cell 7. In order to eliminate this, it is important to quickly discharge the condensed water from the unit cells 8 and 8A.

As a method for discharging the condensed water from the inside of the unit cell (the unit cells 8, 8A, etc.), there is the following method. Suction by capillary force. Evaporation by utilizing the heat generated from a single cell. Extruded using the pressure of the reaction gas.

The method according to the preceding paragraph was used for early space fuel cells using hydrogen and oxygen as reaction gases. The method according to the above item is, for example, the method disclosed in the method for operating a solid polymer electrolyte fuel cell according to Japanese Patent Application No. 6-245813 filed by the same applicant. This method is a method of preventing condensed water from being generated in the unit cell by raising the operating temperature of the unit cell or lowering the humidity of the reaction gas supplied to the unit cell. That is, in order to prevent the PE film from being dried and to evaporate the water moderately, it is necessary to manage and adjust the delicate temperature and humidity. The method according to the above item uses the pressure drop generated in the reaction gas flowing in the flow passage (the groove 811A, the groove 821A, etc.) that allows the reaction gas to flow therethrough, from the flow passage of the condensed water. It is a method of pushing out and discharging. The pressure drop value is determined by the cross-sectional dimension and length dimension of the reaction gas passage and the flow rate of the reaction gas, and the larger the pressure drop value, the greater the ability to discharge the condensed water. Since the present invention belongs to the method according to this section, the method will be further described below.

As a general case, they are connected in parallel with each other.
The gas passes through each of the
Let's consider the case of being swept away. And this
Consider the case where one of them is blocked by water. This place
In this case, the force acting on the water blocking the duct is the capillary force,
Pressure received from gas (equal to the pressure drop value above)
Yes. ), There are three types of gravity. Capillary force f of term₁Is
As is well known, between the surface tension σ of water and the water and the wall of the pipeline.
Is determined by the contact angle φ of, and when the radius of the conduit is r,
It can be represented by the following “formula 3”. Received from the term gas
Force f exerted on water based on pressure₂Is the pressure drop of the gas
Is Δp_sIf the cross-sectional area of the pipeline is S, then
As is known, it can be expressed by the following “formula 4”. Ma
Also, the force f acting on water based on the gravity of the term f_ThreeStuck in the pipeline
The height of the retained water is h, and the flow direction of the gas is gravity.
If the angle made with respect to the working direction of is θ,
Density ρ _wIf the acceleration of gravity is g, then
Finally, it can be expressed by the following “Formula 5”. Capillary force f
₁Is larger in proportion to the pipe diameter, but
Force f on water_ThreeIncreases in proportion to the square of the pipe diameter
The water wicking phenomenon, commonly called the capillary phenomenon,
The smaller the diameter, the more prominent it appears.

[0038]

[Formula 1] f ₁ = 2πrσ · cosφ ………………… (3)

[0039]

[Formula 2] f ₂ = SΔp _s …………………… (4)

[0040]

## EQU3 ## f ₃ = ρ _w ghπr ² · cos θ (5) The forces acting on the water blocking the pipeline are f ₁ , f ₂ and f
₃ is a total, and the condition for discharging this water is that (f ₁ −f ₃ ) <f ₂ and therefore can be expressed by the following “formula 6”.

[0041]

(Equation 4)

Regarding the posture that the pipeline should take in order to facilitate the drainage of water that has blocked the pipeline, from "Equation 6" to c.
It is preferable to set osθ≈1, that is, set θ to zero [degrees]. In the structure of the stack 9 described above, the reaction gas is a gas passage formed in each of the separators 81 and 82 (the same applies to the separators 83 and 84) as indicated by the arrows in FIG. It is based on this reason that the diversion grooves 811A and 821A are arranged so that the supply side thereof is the upper side in the direction of gravity and the discharge side thereof is the lower side in the direction of gravity.

In the present invention, the above-mentioned water retention head p _k is calculated by "Equation 7" using f ₁ and f ₃ defined in "Equation 3" and "Equation 5". It can be shown.

[0044]

[Formula 5] p _k = f ₁ −f ₃ …………………………… (7)

[0045]

In the above-mentioned conventional solid polymer electrolyte fuel cell (stack), for example, in the stack 9 described above, the separator 81,
The pressure drop value Δp _s generated in the grooves 811A and 821A of the groove 82 and the like is set to be larger than the water retention head p _k value of each of the grooves 811A and 821A, and the grooves 811A and 821A are set. The shape and the flow rate of the reaction gas are made to satisfy the relationship according to the above-mentioned “Equation 6”, and the reaction gas is introduced into the grooves 811A and 821A from the upper side in the direction of gravity and from the lower side in the direction of gravity. Since the reaction gas is made to flow out,
In many cases, the stack 9 can be operated without finely controlling and adjusting the temperature and humidity of the reaction gas.

However, the following problem has been newly found. This is because when the reaction gas flows in parallel to each of the plurality of grooves 811A and 821A as in the case of the separators 81 and 82, the grooves 8
In order to equalize the flow rate of the reaction gas flowing through each of 11A and 821A, all grooves 811A and 821A are formed.
It means that it is necessary to remove the water droplets attached to the wall surface of the. The presence of water droplets attached to the wall surface means that the effective flow area of the grooves 811A, 821A for the reaction gas is reduced, and that water droplets are attached to the wall surfaces of some of the grooves 811A, 821A means that Since the effective flow area of the reaction gas in the groove is reduced, the equalization of the flow rate of the reaction gas is hindered.

The water droplets are water droplets and the like that are generated by being attached to the wall surface when the supersaturated steam is condensed.
Then, as will be described below, in the conventional structure such as the stack 9, the condensed water that completely closes the grooves 811A and 821A can be removed.
It has been clarified that the water droplets attached to the wall surface cannot be removed. For this reason, in the groove with water droplets attached to the wall surface, the flow rate of the reaction gas is reduced as compared to the groove with no water droplet attached to the wall surface. For example, the hydrogen utilization rate value for the fuel gas 97 will increase with respect to the average hydrogen utilization rate value in the corresponding separator. Then, as is well known, the increase of the hydrogen utilization rate value means that the generated voltage value of the fuel cell decreases. As a result, in the stack 9 of the conventional example (or the unit cell 8 used therein), as shown by a dotted line in FIG. The power generation voltage value of

By the way, when it is desired to remove water droplets attached to the wall surfaces of the grooves 811A and 821A, the grooves 811
Since A and 821A are not blocked by the condensed water, f ₂ according to the above “equation 4” cannot exist. Effective for removing the water droplets are f ₃ according to the above-mentioned “Equation 5” and the known dynamic pressure Δp _u generated in the reaction gas flowing in the grooves 811A and 821A.

Taking the case where the cross-sectional shape of the flow path of the reaction gas is circular as an example, the dynamic pressure Δp _{u in} the case of a circular tube can be expressed by the following "formula 8" as is well known.

[0050]

[6] _{Δp u = (λl / d)} (ρ g u 2/2) ......... (8) , where the friction coefficient of λ tube, l is the pipe length of, d is a circular tube diameter , Ρ _g is the density of the reaction gas, and u is the flow rate of the reaction gas. When the cross-sectional shape of the flow path of the reaction gas is a rectangle, assuming that the length of the long side of the rectangle is a and the length of the short side of the rectangle is b, d in “Equation 8” is given as By using the equivalent diameter d represented by "Equation 9", "Equation 8"
Can be used as it is.

[0051]

## EQU00007 ## d = 4ab / [2 (a + b)] (9) With respect to λ, if the reaction gas flowing through the pipeline is in a laminar state, ν is the reaction gas. When the kinematic viscosity of
As is known, λ can be represented by the following “Formula 10”.

[0052]

## EQU8 ## λ = 64 / Re = 64ν / (ud) (10) Substituting "Equation 10" into "Equation 8", the relational expression of the dynamic pressure Δp _u is "Equation 11" for the circular pipe. Can be obtained as shown in. Further, "Formula 12" can be obtained by converting "Formula 11" in correspondence with the flow path of the reaction gas having a rectangular cross-sectional shape.

[0053]

## EQU9 ## Δp _u = 32νρ _g u (l / d ² ) (11)

[0054]

[Equation 10] Δp _u = 8πνρ _g l (u / S) (12) As is clear from “Equation 11” and “Equation 12”, when the reaction gas flows through the pipeline in a laminar state. In addition, the generated dynamic pressure Δp _u is proportional to the flow velocity of the reaction gas and the pipe length, and is inversely proportional to the square of the pipe diameter or the cross-sectional area of the pipe. Groove 811A,
Since the reaction gas flowing through the inside of the 821A is in a laminar flow state in almost all cases, "Equation 11" and "Equation 12" are established.
At this time, in order to remove water droplets attached to the wall surface, the dynamic pressure Δp
There are three possible methods for increasing the value of _u .

The flow velocity u of the reaction gas is increased. Increase the pipe length l. The equivalent diameter d of the conduit is shortened. (That is, the cross-sectional area S of the pipeline is reduced.) The method of increasing the flow velocity u in the above term is to increase the supply amount of the reaction gas or to shorten the equivalent diameter d of the pipeline in the above term. , Can be realized. In the solid polymer electrolyte fuel cell (stack), the supply amount of the reaction gas to be supplied is closely related to the power generation efficiency of the stack. As the supply amount of the reaction gas increases, the power generation efficiency decreases. A method of increasing the gas supply amount is not preferable. Further, in the method of increasing the conduit length 1 in the above item, in the conventional technique, the dimension of the long side of the rectangular electrode film is the limit length. This is derived from the above-mentioned conventional coping method for avoiding that the grooves 811A and 821A are blocked by the condensed water, and the condensed water can naturally drop in the grooves 811A and 821A by gravity. This is because Even if it is possible to increase the conduit length l to some extent by making the shape of the electrode film elongate in a constant electrode film area, there is a limit in obtaining a large increase amount.

From the above, as a method of increasing the value of the dynamic pressure Δp _u , the method according to the above-mentioned item has been adopted in many cases. This method also has the effect of increasing the flow velocity u at the same time. By reducing the width and depth of the grooves 811A and 821A, the cross-sectional area S of the conduit can be reduced. However, in this case, as a matter that becomes a constraint condition regarding the increase of the flow velocity u, it is necessary to uniformly distribute the reaction gas to each of the plurality of grooves 811A and 821A connected in parallel. Sometimes. That is, as the width dimension and the depth dimension of the grooves 811A and 821A are reduced, the sectional area S value between the grooves varies due to a processing error.
This is because the reaction gas distributed in each groove becomes non-uniform, and the power generation performance of the fuel cell unit 7 deteriorates for the same reason as described above. For this reason, it is desirable that the cross-sectional area S of the grooves 811A and 821A be large in order to evenly distribute the reaction gas, and it is not possible to proceed with measures only from the viewpoint of increasing the dynamic pressure Δp _u value.

Due to these restrictions, for example, the separators 81 and 82 have the structure of the separator included in the stack according to the prior art.
Water retention head p of a value sufficient to remove condensed water that has completely blocked 1A, that is, according to the above "equation 7".
_Even if a pressure drop Δp _{s of a} value sufficiently exceeding the _k value can be generated, a dynamic pressure Δp of a sufficient value that can remove water droplets attached to the wall surfaces of all the grooves 811A and 821A.
It became clear that it was impossible to increase the flow velocity of the reaction gas enough to obtain the _u value.

The present invention has been made in view of the above-mentioned problems of the prior art, and its object is to remove water droplets adhering to the wall surface of the flow passage through which the fuel gas and the oxidant gas possessed by the separator flow. Another object of the present invention is to provide a solid polymer electrolyte fuel cell capable of achieving the above.

[0059]

Means for Solving the Problems The above-mentioned objects of the present invention are as follows: 1) An electrolyte membrane of a sheet-like solid polymer electrolyte material, and a fuel electrode membrane and an oxidizer electrode membrane bonded to both main surfaces thereof. And a fuel cell that receives the supply of the fuel gas and the oxidant gas to generate DC power, and a separator that is arranged to face each of both main surfaces of the fuel cell, the separator, The gas is supplied to the fuel cells, the gas inlet is introduced into the separator, the gas is discharged from the separator, the outlet is formed along the surface of the separator facing the fuel cell. And a flow path communicating with the inflow port and the outflow port. The flow path is generated when the gas is flowed through the flow path. The pressure drop value is
In a solid polymer electrolyte fuel cell (stack), which is set to be larger than the water retention power head value of the flow path, the separator is substantially orthogonal to the surface facing the fuel cell, Moreover, it has a pair of end faces that are substantially parallel to each other, and the above-mentioned flow passages are mainly formed of partial flow passages that are formed substantially parallel to each other in a relationship that is substantially orthogonal to these end faces. The partial flow path of
This can be achieved by having a structure in which the gas is flowed in such a manner that it has portions connected in series with each other and is communicated with the inflow port and the outflow port.

With this configuration, under the condition that the amount of the reaction gas supplied to the stack is the same, the n flow passages are connected in series while the cross-sectional area of the flow passage remains the same. If it is connected to, the length of the flow passage (which is the pipe length l in the above-mentioned “Equation 8”) and the flow velocity u of the reaction gas in the flow passage are both n times. From this fact, when the above-mentioned “formula 11” and “formula 12” are used, the dynamic pressure Δp _u can be calculated as n ²
You can double it.

Further, in the above, even if the cross-sectional area of the flow path is increased by n ^1/2 with the same amount of reaction gas,
According to “Equation 11” and “Equation 12”, Δp _u can be multiplied by n and the flow velocity u can be multiplied by n ^1/2 . As described above, by applying the present invention, it becomes possible to simultaneously increase the cross-sectional area S of the passage, the flow velocity u of the reaction gas, and the dynamic pressure Δp _u .

2) Further, in the means described in the above item 1, the plurality of partial passages provided in the separator are provided with an inlet for introducing the fuel gas and the oxidant gas supplied to the fuel cell into the separator, This is achieved by a configuration in which all of the above-mentioned gas is connected in series with each other and communicated with the outlet through which the gas flows out from the separator.

With this structure, it is possible to obtain the same action as that of the above item 1 and all the partial flow passages are connected in series with respect to the flow of the reaction gas. Therefore, even if there is a difference in cross-sectional area in each of the partial flow passages, the reaction gas can flow through all the partial flow passages evenly. 3) Further, in the means described in the above item 1, the plurality of partial flow passages included in the separator include an inflow port through which the fuel gas and the oxidant gas supplied to the fuel cell are introduced into the separator, and the gas. A plurality of series connection groups, some of which are connected in series with each other, between the flow outlets flowing out of the separator, and the series connection groups of the partial flow passages are in parallel with each other. It is achieved by adopting a structure in which the inflow port and the outflow port are respectively communicated with each other.

Thus, with this structure, it is possible to obtain the same function as that of the above item 1, and since the electrode film has a large area, the structure according to the above item 2 is adopted. Then, the configuration is useful when applied to a case where the pressure for supplying the gas becomes excessive. 4) Further, it has an electrolyte membrane of a sheet-like solid polymer electrolyte material, and a fuel electrode membrane and an oxidant electrode membrane joined to both main surfaces thereof, respectively, and receives supply of fuel gas and oxidant gas. A fuel cell that generates direct current electric power, and a separator that is arranged so as to face each of both main surfaces of the fuel cell, and the separator supplies the gas supplied to the fuel cell to the separator. The inlet,
The gas, which is discharged from the separator, is formed along the surface of the separator facing the fuel cell to allow the gas to flow therethrough, and is connected to the inlet and the outlet. The flow passage has such a flow passage that the pressure drop value generated when the gas is made to flow through the flow passage is larger than the water retention head value of the flow passage. In the solid polyelectrolyte fuel cell configured as described above, the flow path of the separator is formed so as to surround one of the inflow port and the outflow port, and is continuous with respect to the flow of the gas. , Connecting one end of this passage to one of the inlet and the outlet,
This is achieved by configuring the other end of the communication passage to be connected to the other of the inlet and the outlet formed outside the region where the passage is formed.

The actions described in the above items 1 to 3 are not limited to the flow passage having the structure according to the above items 1 to 3 because the action may occur. The object of the present invention is to achieve the above-mentioned object by obtaining the action described in the above-mentioned items 1 and 2 for a flow passage having a structure not depending on the above-mentioned items 1 to 3. It is a means according to item 4.

5) Furthermore, in the means described in the above item 4, the separator is a region in which an inflow passage is formed in which the fuel gas and the oxidant gas supplied to the fuel cell are introduced into the separator. Formed on the outside of the separator, the gas is formed in the central portion of the area where the flow path is formed through the outlet through which the gas flows out from the separator,
Achieved.

Thus, in the case of this configuration, the gas flowing through the separator flows while entering the inside where the temperature is relatively high in the same unit fuel cell, and the gas relatively flows. It is discharged from the vicinity of the center of the unit fuel cell, which has the highest temperature. For this reason, with this configuration, it is possible to obtain the same action as that of the above-mentioned items 1, 2, and 4, and the temperature is raised sequentially while the gas is flowing, It is also possible to reduce the degree of generation of condensed water due to oversaturation.

[0068]

Embodiments of the present invention will be described below in detail with reference to the drawings. Example 1; FIG. 1 is a schematic view showing the main part of a separator included in a solid polymer electrolyte fuel cell according to an example of the present invention corresponding to claims 1 and 2 and is the same as the case of FIG. It is the figure seen from the direction. In FIG. 1, FIG. 8 and FIG.
The same parts as those of the separator included in the solid polymer electrolyte fuel cell according to the conventional example shown in (4) are designated by the same reference numerals, and the description thereof will be omitted. In addition, in FIG. 1, only the representative reference numerals are shown for the reference numerals given in FIGS. 8 and 9. In addition, in FIG. 1, a groove 829 for accommodating the gas seal body 73 shown in FIGS. 8 and 9 is not shown. It should be noted in advance that this is the same for FIGS. 3 to 7 described later.

In FIG. 1, 1 is the manifold 8 in comparison with the separator 82 according to the conventional example shown in FIGS.
23A is stopped, and a concave groove 821A which is a partial flow passage for allowing the oxidant gas 98 (not shown) to directly flow through the through holes 825A and 826A as shown in the figure.
Is a separator formed by communicating with. Separator 1
The plurality of grooves 821A are connected to each other in series with respect to the flow of the oxidant gas 98 by the groove 11A having the same cross-sectional shape as the groove 821A. The through holes 825B and 826B included in the separator 1 are communicated with the groove 821B (not shown). Hole 825B and through hole 8
26B, they are connected to each other in series with respect to the flow of the heat medium 99.

The interconnection between the grooves is the same as the interconnection of the grooves 821A in the separator 1.
The separator according to the present invention, which corresponds to the separator 81 of the conventional example, which allows the fuel gas 97 to flow therethrough, is basically the same as the separator 1, although the illustration is omitted. Then, the separator that allows the fuel gas 97 to flow is
Through holes 825B, 826B and the heat medium 9 communicated with these holes
9 differs from the separator 1 only in that the flow passages through which the fluid flows are formed in a plane symmetrical portion.

These separators are combined with the fuel cells 7 (not shown) to form a unit fuel cell (unit cell) (not shown) according to the present invention. By constructing a solid polymer electrolyte fuel cell (stack) which is not shown in the present invention by stacking the individual pieces, the conventional unit cell 8 using the separators 81 and 82 of the conventional example is used. The same as in the case of the stack 9 of the conventional example.

Thus, in the separator 1, 1.4 [Nrm ³ / min] is applied to the oxidizer electrode film 7B (not shown) having the same electrode area of 50 [cm ² ] as the conventional example.
Air as the oxidant gas 98 is supplied. The outer dimensions of the oxidizer electrode film 7B are 71 [mm] × 71 [mm], and the cross-sectional dimensions of the groove 821A are 2.0 [mm] in width and 1.2 [mm] in depth. Groove 8 of separator 82
Its cross-sectional area is larger than that of 21A. The separator 1 has 22 grooves 821A, which is the same as the conventional example, and the total length including the groove 11A is 1.6 [m].
The air has a flow rate of 15 [m / s] in the grooves 821A and 11A.
Since it flows at a higher speed than in the case of the conventional example,
A dynamic pressure Δp _u of about 5 [kPa] is obtained.

A fuel gas 97 (not shown) is made to flow in combination with the separator 1. The separator (not shown) has the same 50 [cm ² ] as the oxidizer electrode film 7B.
Pure hydrogen as a fuel gas 97 of 0.17 [Nrm ³ / min] is supplied to a fuel electrode film 7A (not shown) having an electrode area of. The outer dimensions of the fuel electrode film 7A are the same as those of the oxidizer electrode film 7B, 71 [mm] × 71 [m].
m], and the cross-sectional dimension of the groove 811A (not shown) for allowing the fuel gas 97 to flow is 2.0 mm in width,
Groove 8 of separator 1 having a depth of 0.6 mm
It is shallower than 21A. The pure hydrogen described above is used for connecting the groove 811A and the groove 811A to each other.
A dynamic pressure Δp _u of about 1.6 [kPa] can be obtained by flowing through a groove similar to 1A at a flow rate of 3 [m / s].
This value is smaller than the value for the air in the separator 1 in both the flow velocity and the dynamic pressure, but the fact that water is produced in the fuel cells 7 is indicated by the above-mentioned "Formula 2". As described above, since it is mainly on the oxidant electrode film 7B side and the hydrogen concentration is sufficiently high, there is no problem at all.

The stack according to the present invention provided with the separator having the above-mentioned structure has all 22 grooves 811A and 811A.
21A is connected in series with respect to the flow of the reaction gas. As a result, first, both the length of the flow path of the reaction gas (which is the pipe length l in the above-mentioned “Equation 8”) and the flow velocity of the reaction gas in the flow path are increased. As a result, the dynamic pressure Δp _u can be significantly increased from the above-mentioned “Equation 12” (by comparison, the general dynamic pressure Δp _{u in} the case of the conventional example is about 0.04 [kPa]). Then, it becomes possible to remove the water droplets attached to the wall surface of the passage by the large dynamic pressure Δp _u . Therefore, the problem that the effective flow area of the flow path of the reaction gas is reduced due to the water droplets adhering to the wall surface existing in the conventional example is solved.

Further, all the grooves 821A of the oxidizing gas 98 are
Are connected in series, the reaction gas of the same flow rate flows through these grooves (the groove 8 for the fuel gas 97).
11A is exactly the same as the case of the groove 821A. ). As a result, even if there are inconsistencies in the cross-sectional flow areas of the reaction gas due to machining accuracy, adhesion of water droplets to the wall surface, etc., in each of these grooves, there are The problem of uneven distribution of the reaction gas over the grooves will also be solved. Furthermore, since the reaction gas is not shunted, even if the cross-sectional dimension of the reaction gas flow passage is increased, a desired large value can be obtained as the flow rate of the reaction gas. Therefore, the problem of the processing accuracy with respect to is also reduced.

As a result of the above, in the unit cell according to the present invention including the separator having the above-mentioned structure, the generated voltage value can be improved as shown in FIG. Here, FIG. 2 is a graph showing an example of measuring the power generation voltage of the unit fuel cell of the solid polymer electrolyte fuel cell according to the present invention according to Example 1 in comparison with the case of the conventional example. In FIG. 2, the solid line shows the case according to the first embodiment, and the dotted line shows the case of the conventional unit cell 8. In this measurement, the hydrogen utilization rate was 80 [%], the air utilization rate was 20 [%], and the supply pressures of hydrogen and air were both 0.1.
It was carried out under the condition of [MPa]. In the case of the conventional example in FIG. 2, since water droplets are attached to the wall surfaces of some of the grooves 811A and 821A, the distribution of the reaction gas flowing through these grooves becomes uneven, so that it is low. The power generation voltage value is 0.2 [V], which is the limit value of the current density value. On the other hand, in the case of the present invention, since the uneven distribution of the reaction gas does not occur due to the above-mentioned point, the current density value at the point where the generated voltage value becomes the limit value of 0.2 [V] is increased. You can do it.

Further, the stack according to the present invention provided with the separator having the above-mentioned structure has the groove 8 as described above.
Since the water droplets attached to the wall surfaces of 11A and 821A can be removed, naturally, the Δp _s value exceeding the water holding head p _k value according to the above-mentioned “Equation 7” can be obtained, so that the groove 81
The above-mentioned condensed water does not stay in 1A and 821A. Therefore, in this stack, the grooves 811A and 821, which are used in the conventional stack 9 and the like, are performed.
The constraint that A must be placed along the direction of gravity will no longer be imposed. For this,
In this stack, there is no problem even if it is installed in any posture, and for example, the stacking direction of the unit cells may be arranged along the gravity direction. This makes it possible to reduce the footprint of the stack.

Example 2; FIG. 3 schematically shows the main part of a separator provided in a solid polymer electrolyte fuel cell according to a different example of the present invention corresponding to claims 1 and 2, and FIG. It is the figure seen from the same direction as the case. 3, a separator included in a solid polymer electrolyte fuel cell according to an embodiment of the present invention corresponding to claims 1 and 2 shown in FIG. 1 and a solid height according to a conventional example shown in FIGS. The same parts as those of the separator included in the molecular electrolyte fuel cell are designated by the same reference numerals, and the description thereof will be omitted. In addition, in FIG. 3, about the code | symbol attached in FIG. 8 and FIG. 9, only the typical code | symbol was described.

In FIG. 3, 2 is a through hole 825A, 82 for the separator 1 according to the present invention shown in FIG.
6A, 827A, 828A, 825B and 826B
(These six through-holes are collectively referred to as the above-mentioned through-holes 825A and the like in the description of the second embodiment.) The separator has a changed position. Through holes 825A, 826A in the separator 1,
The forming positions of 827A and 828A are the through holes 825A, 826A and 827 in the separator 82 of the conventional example.
It follows the formation positions of A and 828A. Then, the through hole 825 in the separator 82 of the conventional example
The formation positions of A, 826A, 827A, and 828A are the respective grooves 811A and 821A formed through the manifold 823A.
It was established from the need to equalize the distribution of the reaction gas to the.

However, in the separator according to the present invention which does not use the manifold 823A, regardless of the formation position of the through holes 825A, 826A, 827A, 828A, the reaction gas for each groove described in the first embodiment is not described. The feature of eliminating the problem of uneven distribution can be maintained. The review of the formation positions of these through holes in the separator 2 was made with this in mind. That is, the separator 2
In FIG. 1, it can be confirmed by comparing FIG. 1 and FIG. 3 that the lengths of the grooves 811A and 821A in the portion adjacent to the through hole 825A in the reaction gas flow direction of the separator 1 are It is a little shorter than the case. Further, as a result, the groove 11A existing in a portion that is not adjacent to the through hole 825A and the like, and the separator 2
The distance between the end faces 82d and 82e of the is shortened as much as possible. The shape and size of the separator 2 different from the separator 1 shown in FIG. 1 will be described below from the viewpoint of reviewing the separator 1.

First, the distance between the groove 11A existing in a portion not adjacent to the through hole 825A and the end surfaces 82d and 82e of the separator 2 is, for example, the edge portion 82.
f, it is determined in consideration of formation of the groove 829 and the like not shown. The positions where the through holes 825A and the like are formed are
Based on the positions of the end surfaces 82d and 82e thus determined, for example, the formation of the groove 827A and the like, the connection work of the reaction gas pipe to the through hole 931 with the female thread for pipe,
It is determined in consideration of the mounting work of the pipe connection body 991 for the heat medium 99 and the like. Ends of the grooves 811A and 821A adjacent to the through hole 825A and the like, and the groove 11A.
Based on the position of the through hole 825A, etc., the edge 82f, the groove 829, and the groove 827A not shown in the drawings, and the through hole 931 with the female thread for pipe are formed.
It is determined in consideration of the formation of the above. Then, in relation to these, the formation position of the edge portion 82f is determined, and the planar shapes of the fuel electrode film 7A and the oxidizer electrode film 7B, both of which are not shown, are formed in accordance with the formation position of the edge portion 82f. Then, the dimensions will be reviewed.

The stack according to the present invention provided with the separator 2 having the above-described structure has the same function and effect as the stack according to the first embodiment described above, but the size of the electrode film of the stack in the planar direction is reduced. In addition, it is possible to reduce the use area of the solid polymer electrolyte membrane 7C (not shown). Embodiment 3; FIG. 4 is a schematic view showing the main part of a separator included in a solid polymer electrolyte fuel cell according to an embodiment of the present invention corresponding to claims 1 and 3 and is the same as the case of FIG. It is the figure seen from the direction. 4, a separator provided in a solid polymer electrolyte fuel cell according to an embodiment of the present invention corresponding to claims 1 and 2 shown in FIG. 1 and a solid height according to a conventional example shown in FIGS. The same parts as those of the separator included in the molecular electrolyte fuel cell are designated by the same reference numerals, and the description thereof will be omitted. In addition, in FIG. 4, as for the reference numerals given in FIGS. 8 and 9, only representative reference numerals are shown.

In FIG. 4, reference numeral 3 indicates the manifold 8 with respect to the separator 82 according to the conventional example shown in FIGS.
23A is a separator formed by stopping the use of 23A and forming a concave groove 821A which is a partial passage for allowing the oxidant gas 98 to flow therethrough as described below. That is, in the separator 3, first, a plurality of grooves 821A (a specific number in this case will be described later) are connected in series with each other with respect to the flow of the oxidant gas 98 by the grooves 11A. Such a series connection path of the grooves 821A includes a plurality of groups (3 in FIG. 4).
The case of a group is illustrated. ) Is formed. Between the series connection path of the grooves 821A of the plurality of groups, the groove 821A and the groove 11A are connected.
The lengths of the flow paths of the reaction gas formed by and are set to be substantially equal. Then, each of the series connection paths of the grooves 821A of the plurality of groups is connected in parallel to each other through the short groove 31A, and the through hole 825 is formed.
A is communicated with the through hole 826A.

The through hole 825 of the separator 3
B, 826B and a connection relationship between the groove 821B (not shown), the relationship between the separator 3 and the separator according to the present invention corresponding to the separator 81 of the conventional example that allows the fuel gas 97 to flow, and the like. Since the relationship regarding the unit cell or the stack configured by using the separator of 1 is the same as that of the separator 1 according to the first embodiment, the description thereof will be omitted.

Thus, the separator 3 has the same structure as that of the conventional example.
6.7 [Nrm ³ ] for the oxidizer electrode film 7B (not shown) having a wide electrode area of 250 [cm ² ].
/ Min] of air is supplied. The outer dimensions of the oxidizer electrode film 7B are 160 [mm] × 160 [mm] and the groove 821A.
The cross-sectional dimension of is both 0 mm in both width and depth. The cross-sectional area is larger than the groove 821A of the separator 1 according to the first embodiment. Groove 821 of separator 1
The total number of A is 54, and each 18 is the groove 821.
A series connection path of A is formed. The total length of each series connection including the groove 11A is 2.85 [m].

The length of the flow path of the reaction gas in the separator 3 (which is the pipe length l in the above "formula 12").
Is the total extension of 2.85 [m], and the dynamic pressure Δp _u
The value of is obtained corresponding to the pipe length l of 2.85 [m]. In the case where all the grooves 821A are connected in series with respect to the flow of the reaction gas, in the case where the grooves are formed by n (n = 3 in the case of the separator 3) series connection paths, The path length l and the reaction gas flow rate u are both 1 / n
Therefore, the value of the dynamic pressure Δp _u becomes 1 / n ² from the above-mentioned “Equation 12”. By doing so, in the case of a separator that supplies a reaction gas to a wide electrode area, an excessive dynamic pressure Δp _u
It is possible to avoid the occurrence of. The dynamic pressure Δp _u value in the separator 3 is still about 8 [kPa], which is larger than that in the separator 1.

The stack according to the present invention, which is provided with the separator 3 having the above-mentioned structure, can naturally have the same operation and effect as the stack according to the first embodiment. Moreover, since the electrode film has a large area, the configuration according to Example 1 is a useful configuration when it is applied when the pressure for supplying the reaction gas becomes excessive.

Example 4; FIG. 5 schematically shows the main part of a separator included in a solid polymer electrolyte fuel cell according to still another example of the present invention corresponding to claims 1 and 2, and FIG. It is the figure seen from the same direction as the case of. 5, a separator provided in a solid polymer electrolyte fuel cell according to an embodiment of the present invention corresponding to claims 1 and 2 shown in FIG. 1 and a solid height according to a conventional example shown in FIGS. The same parts as those of the separator included in the molecular electrolyte fuel cell are designated by the same reference numerals, and the description thereof will be omitted. In addition, in FIG. 5, the reference numerals given in FIG. 8 and FIG.
Only representative symbols are shown.

In FIG. 5, a plurality of grooves 821A (to be described later) similar to those of the separator 1 according to the present invention shown in FIG. The series connection path 41 of the grooves 821A connected to the
The case of a group is illustrated. ) Is formed. In order to distinguish each of the plurality of serial connection paths 41, the reference numeral 41 is followed by A, B, and C in FIG. As in the case of the separator 1, the through-holes 825 are formed in both ends of the groove 821A in each series connection path 41.
A and 826A are directly connected to each other.

The through hole 825 of the separator 4
B, 826B and a connection relationship between the groove 821B (not shown), the relationship between the separator 4 and the separator according to the present invention corresponding to the separator 81 of the conventional example that allows the fuel gas 97 to flow, and the like. Since the relationship regarding the unit cell or the stack configured by using the separator of 1 is the same as that of the separator 1 according to the first embodiment, the description thereof will be omitted.

Thus, the electrode area / outer dimensions of the oxidizer electrode film 7B (not shown) of the object to which the separator 4 supplies air, the total number of the grooves 821A held by the separator 4, the cross-sectional dimensions, etc. are all as described above. This is the same as the case of the separator 3 according to the third embodiment. Therefore, the length of the flow path of the reaction gas and the dynamic pressure Δ
The p _u value and the like are also the same as in the case of the separator 3.

Therefore, the stack according to the present invention, which is provided with the separator 4 having the above-mentioned structure, is the same as that of the third embodiment.
Will have the same action and effect as the stack.
In addition to this, in the stack according to the fourth embodiment, the amount of reaction gas supplied to each series connection path 41 can be individually adjusted as needed, and in the case of a stack having a wide electrode area, etc. Thus, the reaction gas can be more evenly distributed in the surface direction of the electrode. Although multiple reaction gas supply systems and reaction gas flow rate control systems associated with the stack are required, using the above-mentioned features is particularly important when operating with a small amount of reaction gas supply or high. This is effective when it is necessary to operate at a current density.

Example 5; FIG. 6 schematically shows the main part of a separator provided in a solid polymer electrolyte fuel cell according to an example of the present invention corresponding to claims 4 and 5 and is shown in FIG. It is the figure seen from the same direction as the case. 6, the same parts as those of the separator included in the solid polymer electrolyte fuel cell according to the conventional example shown in FIGS. 8 and 9 are designated by the same reference numerals, and the description thereof will be omitted. In addition, in FIG. 6, only the typical reference numerals are shown for the reference numerals given in FIGS. 8 and 9.

In FIG. 6, 5 is a concave groove 821 with respect to the conventional separator 82 shown in FIGS. 8 and 9.
Instead of A and the convex partition wall 822A, the concave groove 5 is formed.
1A and the convex partition wall 52A are used, the use of the manifold 823A is stopped, and the through holes 825A and 826A are directly communicated with the groove 51A.
The through hole 826A, which is the reaction gas outlet, is formed in the through hole forming portion 53A formed in the central portion of the separator 5, which is one of the features of the configuration according to this embodiment. The through-hole forming portion 53A is formed so as to be continuous with the partition wall 52A, and the tops thereof are both convex partition walls 8 of the conventional example.
Like 22A, it is formed so as to be flush with the side surface 82c (not shown).

The groove 51A of the separator 5 has the same sectional shape as the concave groove 821A of the conventional example, and the through hole 8
25A and through hole 826A, through hole forming portion 53A
Another feature of the structure according to this embodiment is that they are continuously formed so as to surround each other, as shown in FIG. Then, the through hole 825A, which is the inflow port of the reaction gas, is formed at the outermost portion of the region where the groove 51A is formed.

The through hole 825 of the separator 5
B, 826B and a connection relationship between a groove 821B (not shown), the relationship between the separator 5 and the separator according to the present invention corresponding to the separator 81 of the conventional example that allows the fuel gas 97 to flow therethrough, and the like. Since the relationship regarding the unit cell or the stack configured by using the separator of 1 is the same as that of the separator 1 according to the first embodiment, the description thereof will be omitted.

Thus, the electrode area and external dimensions of the oxidizer electrode film 7B (not shown) of the object to which the separator 5 supplies air, the cross-sectional dimensions of the groove 51A of the separator 5, the total extension, etc. are all as described above. Separator 1 according to Example 1 of
Is equivalent to Therefore, the dynamic pressure Δp _u value and the like obtained by the separator 5 are also the same as those of the separator 1.

Therefore, the stack according to the present invention, which is provided with the separator 5 having the above-mentioned structure, is the same as that of the first embodiment.
Will have the same action and effect as the stack.
In addition to this, in the stack according to the fifth embodiment, the air flowing in the separator 5 flows while sequentially entering the inside where the temperature is relatively high in the same unit fuel cell, and is relatively the most. It will be discharged from the vicinity of the center of the unit fuel cell, which becomes hot. The air flowing through the groove 51A flows through while absorbing the water vapor generated in the oxidizer electrode film 7B as described above. This air also has a characteristic configuration of this embodiment. , Groove 5
It is possible to reduce the degree of generation of condensed water due to supersaturation by sequentially raising the temperature while flowing through the inside of 1A.

Although not mentioned in the above description of the third to fifth embodiments, the first embodiment also applies to these.
It is needless to say that the outer shape of the electrode film of the stack in the planar direction can be reduced in size by the same structure as that of the second embodiment. Embodiment 6; FIG. 7 is a schematic view showing the main part of a separator provided in a solid polymer electrolyte fuel cell according to different embodiments of the present invention corresponding to claims 4 and 5, and is the same as the case of FIG. It is the figure seen from the direction. In FIG. 7, a separator provided in a solid polymer electrolyte fuel cell according to an embodiment of the present invention corresponding to claims 4 and 5 shown in FIG. 6 and a solid height according to a conventional example shown in FIGS. The same parts as those of the separator included in the molecular electrolyte fuel cell are designated by the same reference numerals, and the description thereof will be omitted. In addition, in FIG. 7, only the typical reference numerals are shown as the reference numerals given in FIGS. 8 and 9.

In FIG. 7, reference numeral 6 denotes a separator whose outer shape is circular, in contrast to the separator 5 according to the present invention shown in FIG. However, the through holes 825B and 826B included in the separator 6 are not shown in the groove 82.
1B, the groove 821B of the separator 6 is different from the case of the separator 82 of the conventional example in that the groove 5 is formed between the through hole 825B and the through hole 826B.
It is formed in the same manner as 1A. In addition, the separator 6
Then, the configuration is similar to the configuration according to the second embodiment with respect to the first embodiment.

The relationship between the separator 6 and the separator according to the present invention corresponding to the separator 81 of the conventional example that allows the fuel gas 97 to flow therethrough, and the unit cells and stacks using these separators The relationship involved is the same as in the case of the separator 1 according to the first embodiment described above, and therefore its description is omitted. Then, the separator 6
The oxidant electrode film 7 for supplying air to the electrode is omitted.
The electrode area of B, the cross-sectional dimensions of the groove 51A of the separator 6 and the total extension are all the same as those of the separator 5 according to the fifth embodiment. Therefore, the dynamic pressure Δp _u value and the like obtained by the separator 6 are also the same as those of the separator 6. Therefore, the stack according to the present invention including the separator 6 having the above-described structure has the same operation and effect as the stack according to the fifth embodiment. That is, when the fifth embodiment and the sixth embodiment are put together, it can be said that the stack according to the present invention is not limited to the rectangular outer shape of the separator and has a feature that it can be formed in an appropriate shape as needed. is there.

In the above description of the fifth and sixth embodiments, the reaction gas flow path provided in the separator is meandering so as to surround the through hole forming portion formed in the central portion of the separator. Although it has been described above, the present invention is not limited to this, and for example, the flow path of the reaction gas may be formed so as to spirally surround the through hole forming portion.

In the above description of Examples 1 to 6, the separator included in the stack has the same basic structure as the separators 81 and 82 according to the conventional example, but the present invention is not limited to this. For example, it may have the same basic configuration as the separators 83 and 84 according to different conventional examples. However, in the separator having a plurality of independent series connection paths according to the fourth embodiment, the through holes having the same pressure value (for example, inflow ports) are arranged so as to be adjacent to each other. It is preferable that the consideration be given to reduce the leakage of the reaction gas between the independent series connection paths.

[0104]

According to the present invention, the following effects can be obtained by adopting the structure described in the section for solving the above-mentioned problems. The flow velocity of the reaction gas flowing through the passage of the separator,
By increasing the length of the flow path of the reaction gas at the same time, it is possible to increase the obtained dynamic pressure, and it is possible to remove water droplets adhering to the wall surface of the flow path using this large dynamic pressure. Becomes As a result, a uniform distribution of the reaction gas can be achieved, and the power generation performance of the solid polymer electrolyte fuel cell (stack) is, for example, a current density value at which a power generation voltage value of 0.2 [V] which is a limit value is obtained. Can be improved by about 30 [%].

The reaction gas flow passage is formed by connecting the reaction gas inflow port and the reaction gas outflow port in series with each other. The flow rate of the gas can be made invariable and the problems due to uneven distribution of the reaction gas can be eliminated. By forming the flow path of the reaction gas by connecting the reaction gas inflow port and the reaction gas flow port in series with each other,
It is possible to eliminate the need for installing manifolds at the inlet and outlet. This makes it possible to form the inflow port and the outflow port in appropriate portions, reduce the outer shape of the electrode film of the stack in the planar direction, and reduce the manufacturing cost thereof.

A reaction gas flow path is formed by connecting a reaction gas flow path in series between the reaction gas inflow port and the reaction gas flow out port to prevent the reaction gas from being shunted. Even if the cross-sectional dimension of the passage is increased, a desired large value can be obtained as the flow rate of the reaction gas. This allows
The processing accuracy related to the cross-sectional dimension of the flow path of the reaction gas is reduced, which also makes it possible to reduce the manufacturing cost of the stack.

Since a large dynamic pressure can be obtained as described above, the condensed water accumulated in the reaction gas passage can be surely removed. Therefore, in the stack according to the present invention, the reaction gas such as the conventional example is used. That is, the restriction that the flow passage of must be arranged along the direction of gravity is eliminated. As a result, the stack can be installed in an appropriate posture, and the installation area of the stack can be reduced.

By forming the reaction gas outlet in the central portion of the separator, the reaction gas is sequentially heated while flowing through the passage, and the degree of generation of condensed water due to supersaturation is increased. Can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic view showing a main part of a separator provided in a solid polymer electrolyte fuel cell according to an embodiment of the present invention corresponding to claims 1 and 2 and seen from the same direction as in the case of FIG. 9 described later. Figure

FIG. 2 is a graph showing an example of measurement of power generation voltage of a unit fuel cell of the solid polymer electrolyte fuel cell according to the present invention according to Example 1 in comparison with the case of a conventional example.

FIG. 3 schematically shows the main part of a separator provided in a solid polymer electrolyte fuel cell according to different embodiments of the present invention corresponding to claims 1 and 2 and is viewed from the same direction as in the case of FIG. 9 described later. Figure

FIG. 4 is a schematic view showing a main part of a separator provided in a solid polymer electrolyte fuel cell according to an embodiment of the present invention corresponding to claims 1 and 3 and viewed from the same direction as in the case of FIG. 9 described later. Figure

FIG. 5 is a schematic view showing a main part of a separator provided in a solid polymer electrolyte fuel cell according to still another embodiment of the present invention corresponding to claims 1 and 2, and from the same direction as in the case of FIG. 9 described later. View

FIG. 6 schematically shows a main part of a separator included in a solid polymer electrolyte fuel cell according to an embodiment of the present invention corresponding to claims 4 and 5, and is viewed from the same direction as in the case of FIG. 9 described later. Figure

FIG. 7 is a schematic view showing a main part of a separator provided in a solid polymer electrolyte fuel cell according to different embodiments of the present invention corresponding to claims 4 and 5, and is viewed from the same direction as in the case of FIG. 9 described later. Figure

FIG. 8 is a cross-sectional view schematically showing an essential part of a unit fuel cell provided in a solid polymer electrolyte fuel cell of a conventional example in an expanded state and seen from the upper side thereof.

9 is a view of the separator shown in FIG. 8 as seen from the direction of arrow P in FIG.

FIG. 10 is a configuration diagram of a main part schematically showing a conventional solid polymer electrolyte fuel cell, in which (a) is a side view thereof,
(B) Top view

11 is a detailed sectional view of a Q portion in FIG.

FIG. 12 is a cross-sectional view schematically showing an essential part of a unit fuel cell of a different case included in a solid polymer electrolyte fuel cell of a conventional example in an expanded state and seen from the upper side thereof.

[Explanation of symbols]

 1 Separator 11A Groove 821A Partial flow path (groove) 825A Through hole 826A Through hole 825B Through hole 826B Through hole

Claims (5)

[Claims] 1. A sheet-shaped solid polymer electrolyte material having an electrolyte membrane, and a fuel electrode film and an oxidant electrode film bonded to both main surfaces thereof, respectively, for supplying fuel gas and oxidant gas. A fuel cell that receives and generates direct-current power is provided, and a separator that is arranged to face each of both main surfaces of the fuel cell, and the separator supplies the gas supplied to the fuel cell to the separator. And an outlet through which the gas flows out from the separator, and the inlet is formed along the surface of the separator facing the fuel cell to allow the gas to flow therethrough. And a flow passage communicated with the outflow port. The flow passage has a water retention force head having a pressure drop value generated when the gas is caused to flow through the flow passage. Set to be greater than the value In the solid polymer electrolyte fuel cell, the separator has a pair of end faces that are substantially orthogonal to the face facing the fuel cell and are substantially parallel to each other. Is formed mainly by partial flow passages formed by being substantially parallel to each other in a relationship substantially orthogonal to each other, and these partial flow passages are portions connected in series with each other with respect to the flow of the gas. A solid polyelectrolyte fuel cell, comprising: 2. The solid polymer electrolyte fuel cell according to claim 1, wherein in the plurality of partial flow passages of the separator, the fuel gas and the oxidant gas supplied to the fuel cell are introduced into the separator. A solid polymer electrolyte fuel cell, characterized in that all of them are connected in series and communicated with each other between an inlet and an outlet through which the gas flows out from the separator. 3. The solid polymer electrolyte fuel cell according to claim 1, wherein in the plurality of partial flow passages of the separator, the fuel gas and the oxidant gas supplied to the fuel cell are introduced into the separator. Between the inflow port and the outflow port from which the gas flows out from the separator, a plurality of series connection groups, some of which are connected in series, are formed, and the series connection group of the partial flow passages is A solid polymer electrolyte fuel cell, wherein the solid polymer electrolyte fuel cells are arranged in parallel with each other and are respectively connected to an inlet and an outlet. 4. An electrolyte membrane of a sheet-shaped solid polymer electrolyte material, and a fuel electrode membrane and an oxidizer electrode membrane bonded to both main surfaces of the electrolyte membrane. A fuel cell that receives and generates direct-current power is provided, and a separator that is arranged to face each of both main surfaces of the fuel cell, and the separator supplies the gas supplied to the fuel cell to the separator. And an outlet through which the gas flows out from the separator, and the inlet is formed along the surface of the separator facing the fuel cell to allow the gas to flow therethrough. And a flow passage communicated with the outflow port. The flow passage has a water retention force head having a pressure drop value generated when the gas is caused to flow through the flow passage. Set to be greater than the value In the solid polymer electrolyte fuel cell, the flow path of the separator is formed so as to surround one of the inflow port and the outflow port, and is continuously formed with respect to the flow of the gas. One end of the flow channel is connected to one of the inflow port and the outflow port, and the other end of the flow channel is connected to the inflow port formed outside the region where the flow channel is formed. A solid polymer electrolyte fuel cell, characterized in that it is connected to the other of the outlets. 5. The solid polymer electrolyte fuel cell according to claim 4, wherein the separator has an inflow passage through which a fuel gas and an oxidant gas supplied to the fuel cell are introduced into the separator. The solid polymer electrolyte fuel cell is characterized in that the solid polymer electrolyte fuel cell is formed on the outside of the region where the gas flows out from the separator and is formed at the center of the region where the flow passage is formed.