WO2009028331A1

WO2009028331A1 - Cell for fuel cell and fuel cell

Info

Publication number: WO2009028331A1
Application number: PCT/JP2008/064502
Authority: WO
Inventors: Chisato Kato
Original assignee: Toyota Jidosha Kabushiki Kaisha
Priority date: 2007-08-10
Filing date: 2008-08-06
Publication date: 2009-03-05

Abstract

Disclosed is a cell for fuel cells comprising a power generation region wherein a junction body (12) and first and second gas diffusion layers (14) are laminated for generating power, and a manifold region formed around the power generation region and provided with a manifold opening (18) for passing a gas or the like therethrough. One of the first and second gas diffusion layers (14) extends to the manifold region, and a peripheral portion (14c) is hermetically sealed by being impregnated with a liquid resin for formation of a gasket body (16) which is formed around the manifold opening (18). The porosity of a boundary portion (14b) of the first and second gas diffusion layers (14) is lower than the porosity of a power generation portion (14a) and the peripheral portion (14c).

Description

Technical field of fuel cell and fuel cell

The present invention relates to a fuel cell and a fuel cell. In particular, the first and second gas diffusion members in the anode and the cathode suppress the impregnation of the liquid resin into the power generation region while hermetically sealing the manifold opening. The present invention relates to a fuel cell and a fuel cell capable of reducing the layer thickness while preventing cross leak and short circuit.

Background art

For example, as shown in FIG. 19, a polymer electrolyte fuel cell is composed of an electrolyte membrane 92 made of a solid polymer membrane sandwiched between two electrodes, a fuel electrode 96 and an air electrode 94 (ME A- Memb rane E lectrode As s emb ly) is the smallest unit of cells that are sandwiched between two separators 90. Usually, multiple cells are stacked to form a fuel cell stack (FC stack). I am trying to get it.

In general, the power generation mechanism of a polymer electrolyte fuel cell is such that a fuel gas (anode side electrode) 96 is a fuel gas, for example, a hydrogen-containing gas, while an air electrode (force sword side electrode) 94 is an oxidant gas, for example, A gas or air containing mainly oxygen (0 ₂ ) is supplied. The hydrogen-containing gas is supplied to the fuel electrode 96 through the fuel gas flow path, and is decomposed into electrons and hydrogen ions (H +) by the action of the electrode catalyst. The electrons move from the fuel electrode 96 to the air electrode 94 through an external circuit, and produce an electric current. On the other hand, hydrogen ions (H +) pass through the electrolyte membrane 92 and reach the air electrode 94, combine with oxygen and electrons that have passed through the external circuit, and become reaction water (H ₂ 0). Heat generated at the same time as the bonding reaction of hydrogen (H ₂ ), oxygen (0 ₂ ), and electrons is recovered by cooling water.

In recent years, a component for a fuel cell in which a joined body and a gas diffusion layer that can be configured with a small number of parts in a unit cell are formed into a body has been proposed (for example, Patent Document 1). As shown in FIG. 20, this fuel cell component is composed of electrolyte membrane 1 and electrolyte membrane 1 on both sides. It has MEA consisting of gas diffusion layers 2 and 3 integrally formed through catalyst support layers 2 a and 3 a constituting the electrode, and has a constant width from the periphery of gas diffusion layers 2 and 3 to the inside. In addition, the impregnation zone portions 2 b and 3 b made of liquid rubber or synthetic resin are provided, and the gasket member 4 made of an elastic material is molded so as to wrap the entire outer surface of the impregnation zone portions 2 b and 3 b. ing.

Further, in the membrane electrode assembly in Patent Document 2, as shown in FIG. 21, reinforcing layers 5 are provided on both surfaces of the electrolyte membrane 1, and catalyst layers 2 a and 3 a are respectively provided on a part of each reinforcing layer 5. The gas diffusion layers 2 and 3 are laminated and formed. On the other hand, the manifold opening 11 of the membrane electrode assembly is provided with reinforcing layers 5 on both sides of the electrolyte membrane 1, and each reinforcing layer 5 has an adhesive layer 8, a spacer layer 6 and an impregnated portion 7. The seal portion 9 is formed on the surface of the impregnation portion 7 in the in-plane inner direction and the in-plane outer direction with respect to the manifold opening portion 11. Therefore, as shown in FIG. 21, an adhesive layer 8 and a spacer layer 6 are formed on the outer peripheral portion of the joined body, and the outer peripheral portions of the gas diffusion layers 2 and 3 of the anode and the force sword are further managed. By extending each to the hold region and impregnating the outer periphery with a sealing material to form the impregnated portion 7, the gas diffusion layer is prevented from biting into the joined body due to the compressive stress during molding, and the electrolyte Membrane electrode assemblies that suppress the occurrence of membrane damage have been proposed.

Patent Document 1: Japanese Patent Laid-Open No. 2 0 06 6-2 3 6 9 5 7

Patent Document 2: Japanese Patent Laid-Open No. 2 07 4-4 3 4 8

Problems to be solved by the invention

Even if the gas diffusion layer is simply extended to the manifold region and the periphery of the extended gas diffusion layer is impregnated with resin or sealing material, the gas or the sealing material is not impregnated with certainty. On the other hand, if the resin or sealing material is impregnated into the power generation area of the gas diffusion layer, the gas supply area supplied to the joined body in the power generation area will decrease. The power generation efficiency of the battery may be reduced. In addition, since the unit cell configuration proposed in Patent Document 2 has an adhesive layer and a spacer layer, the number of parts per unit cell is increased, and the multilayer structure is used. Therefore, the thickness of the unit cell increases, and the fuel cell in which the cells are stacked may be increased in size. Means for solving the problem

The present invention has been made in view of the above problems, and provides a fuel cell and a fuel cell that can reduce the number of parts of a unit cell, improve gas sealability, and can be downsized. . In order to achieve the above object, the fuel cell and fuel cell of the present invention have the following characteristics.

(1) A joined body having a fuel electrode and an air electrode on an electrolyte membrane, a first gas diffusion member for supplying fuel gas to the fuel electrode, and a second gas diffusion member for supplying oxidant gas to the air electrode And a pair of separators sandwiching the first gas diffusion member, the joined body, and the second diffusion member, and a power generation region in which the joined body is located. A manifold region provided around the power generation region and formed with a manifold opening through which a fuel gas, an oxidant gas, and a coolant are circulated, and the first gas diffusion member or the first At least one of the two gas diffusion members extends to the manifold region and is impregnated with a liquid resin and hermetically sealed, and the power generation in the first gas diffusion member and the second gas diffusion member is performed. Areas and the above two hold The porosity of the boundary between the band is at least the first gas diffusion member and the relatively small fuel cell compared to the porosity of the power generation region and Ma two hold area of the second gas diffusion member.

The boundary between the first gas diffusion member and the second gas diffusion member has a porosity that is suitable for preventing the impregnated liquid resin from entering the power generation region and is difficult for gas to pass through. In addition, the gas diffusion area is maintained in the power generation region and the gas diffusibility in the power generation region is improved.

(2) The fuel cell according to (1), wherein the first gas diffusion member Alternatively, either one of the second gas diffusion members is a fuel cell that extends to the manifold region and is impregnated with a liquid resin and hermetically sealed. Either the first gas diffusion member or the second gas diffusion member is extended to the manifold region to prevent gas leakage and short circuit between the anode and the cathode in the manifold region. be able to. Since the liquid resin is impregnated in the extended gas diffusion member, even if there is no adhesive layer as in Patent Document 2, it is mechanically bonded and gas sealing performance is improved.

(3) In the fuel cell cell according to (1) or (2), pores at a boundary portion between the power generation region and the manifold region in the first gas diffusion member and the second gas diffusion member. The rate is a fuel cell that is smaller than the porosity of the manifold region in the first gas diffusion member and the second gas diffusion member. With the above configuration, the liquid resin can be prevented from being impregnated into the power generation region of the first and second gas diffusion members.

(4) In the fuel cell cell according to any one of (1) to (3), the joined body may further include a liquid resin extending to the manifold region and hermetically sealing. It is a fuel cell to be bonded.

Since the joined body generally has a high affinity with the liquid resin that hermetically seals the manifold region, the joined body that extends to the manifold region and the liquid resin that hermetically seals the manifold region. Adhesion reliability of the fuel cell is further ensured by bonding. Therefore, even without an adhesive layer as in Patent Document 2, the fuel cells are more mechanically coupled and the gas sealability is improved.

(5) In the fuel cell according to any one of (1) to (4), the first diffusion member and the second diffusion member are provided on the fuel electrode and the air electrode, respectively. It is the cell for fuel cells which is a gas diffusion layer.

The number of parts of the unit cell can be reduced, and the gas sealing performance in the manifold region can be improved. (6) In the fuel cell according to any one of (1) to (4), the separator is a flat separator whose surface on the joined body side is a smooth surface, and the first diffusion. The member and the second diffusion member are for a fuel cell, which is a porous channel layer disposed between each gas diffusion layer provided in each of the fuel electrode and the air electrode and the flat separator overnight. Cell.

Since the porous channel layer is made of metal, the strength of the manifold region, particularly during heating, is improved by impregnating the liquid resin in the manifold region compared to the gas diffusion layer. As a result, deformation of the manifold region due to pressing and gas pressure during molding is suppressed, and gas sealing performance is further improved.

(7) In the fuel cell according to any one of (1) to (6), a pore diameter at a boundary portion between the first gas diffusion member and the second gas diffusion member is 20 m or less. This is a fuel cell.

In general, in a fuel cell, it is said that the pore diameter at which the liquid resin cannot flow is 20 / m or less, and the pores at the boundary between the first gas diffusion member and the second gas diffusion member. By setting the pore diameter to 20 / im or less, it is possible to suppress impregnation of the liquid resin at the boundary portion, and thus it is possible to perform good molding processing.

(8) In the fuel cell according to the above (6), the porous body flow path layer has a porosity at a boundary between the power generation region, the manifold region, and the power generation region and the manifold region. It is a cell for fuel cells that is a different type of lath cut metal or expanded metal.

The above-mentioned lath cut metal and expanded metal can be variably processed to a desired porosity and can be formed to a desired thickness, and also function as a current collector because they are made of metal. Can be made.

(9) In the fuel cell according to any one of (1) to (8), the manifold region includes the first gas diffusion member, the joined body, and a second diffusion. A gasket that integrates the member and hermetically seals the periphery of the manifold opening, and is provided with one of the first gas diffusion member and the second gas diffusion member. The peripheral portion enlarged in the manifold region is a fuel cell unit located at the center in the thickness direction of the gasket.

By positioning the peripheral edge of either the first or second gas diffusion member in the center of the thickness direction of the gasket, against the pressure applied to the gasket from above and below when stacking unit cells, Since the reaction force due to the resin forming the gasket works equally, distortion of the gasket due to pressing can be suppressed. This further improves the gas sealing performance of the fuel cell when unit cells are stacked.

(10) A fuel cell in which the cells for fuel cells according to any one of (1) to (9) above are stacked.

By stacking cells with a reduced number of parts, it is possible to reduce the size of the fuel cell, improve gas sealing performance, and improve the power generation efficiency per fuel cell. The invention's effect

According to the present invention, the number of parts of a unit cell can be reduced, the gas sealing performance can be improved, and the power generation efficiency per fuel cell can be improved. Brief Description of Drawings

FIG. 1 is a cross-sectional view illustrating an example of the configuration of a membrane electrode assembly in a fuel cell according to the present invention.

FIG. 2 is a cross-sectional view for explaining an example of the configuration of another membrane electrode assembly in the fuel cell of the invention.

FIG. 3 is a cross-sectional view for explaining an example of the configuration of another membrane electrode assembly in the fuel cell of the invention.

FIG. 4 is a cross-sectional view for explaining an example of the configuration of another membrane electrode assembly in the fuel cell of the invention. FIG. 5 is a diagram for explaining an example of the configuration of another membrane electrode assembly in the fuel cell of the invention.

FIG. 6 is a cross-sectional view for explaining an example of the configuration of another membrane electrode assembly in the fuel cell of the invention.

FIG. 7 is a cross-sectional view for explaining an example of the configuration of another membrane electrode assembly in the fuel cell of the invention.

FIG. 8 is a cross-sectional view for explaining an example of the configuration of another membrane electrode assembly in the fuel cell of the invention.

FIG. 9 is a cross-sectional view for explaining a production example of another membrane electrode assembly in the fuel cell of the invention.

FIG. 10 is a diagram for explaining an example of the configuration of another membrane electrode assembly in the fuel cell of the invention.

FIG. 11 is a perspective view showing an example of a gas diffusion member used for the porous body flow path layer. FIG. 12 is a schematic diagram showing the configuration of a lasscut device for manufacturing a gas diffusion member used for a porous body flow path layer.

FIG. 13 is a diagram for explaining an example of the process of the method for producing a gasket-type membrane electrode assembly.

FIG. 14 is a cross-sectional view showing an example of the structure of a fuel cell in the present invention. FIG. 15 is a cross-sectional view showing an example of the structure of another fuel cell according to the present invention.

FIG. 16 is a cross-sectional view showing an example of the structure of another fuel cell according to the present invention.

FIG. 17 is a cross-sectional view showing an example of the structure of another fuel cell according to the present invention.

FIG. 18A is a diagram for explaining an example of forming a sealing portion.

FIG. 18B is a diagram for explaining another example of forming a sealing portion.

FIG. 19 is a diagram for explaining the cell configuration of the fuel cell and the mechanism during power generation.

FIG. 20 is a partial cross-sectional view showing an example of the configuration of a conventional fuel cell component. FIG. 21 is a partial cross-sectional view showing an example of the structure of a conventional membrane electrode assembly. Explanation of symbols

10 A, 1 0 B, 10 C, 10 D, 20 A, 20 B, 20 C, 20 D, 30, 40 Membrane electrode assembly, 12 assembly, 14 gas diffusion layer, 14 a, 24 a Power generation region , 14 b, 24 b border, 14 c, 24 c peripheral edge, 16 gasket body, 18 manifold hold, 24, 24 A, 24 B porous body channel layer. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. First embodiment.

As shown in FIG. 1, the fuel cell cell of the present embodiment (hereinafter also referred to as “unit cell”) includes a joined body 12 having a fuel electrode and an air electrode on an electrolyte membrane, a fuel electrode in the joined body 12, and A membrane electrode assembly 1 OA composed of first and second gas diffusion layers 14 for supplying fuel gas and oxidant gas to each air electrode is sandwiched by a pair of separators (not shown) described later. Become. In the present embodiment, the first and second gas diffusion members of the present invention are gas diffusion layers.

Furthermore, the fuel cell according to the present embodiment includes a power generation region in which the joined body 12 and the first and second gas diffusion layers 14 are stacked and capable of generating power, and is provided around the power generation region. A manifold region in which a manifold opening 18 for allowing the fuel gas, the oxidant gas and the refrigerant to circulate is formed, and one of the first and second gas diffusion layers 14 is The gas diffusion layer 14 is impregnated with a liquid resin and hermetically sealed. Further, around the manifold opening portion 18, a gasket body 16 having elasticity formed by curing a liquid resin is formed, and the peripheral portion 14 c also functions as a core material of the gasket body 16. Yes. In the fuel cell according to the present embodiment, the porosity of the boundary portion 14b between the power generation region and the manifold region in the first and second gas diffusion layers 14 described above is at least the first. , Porosity and power generation region 14a in the second gas diffusion layer 14 It is relatively small compared to the porosity of the peripheral edge 14 c in the two-hold region. Further, the porosity of the boundary portion 14 b in the first and second gas diffusion layers 14 is equal to the porosity of the peripheral portion 14 c of the manifold region in the first and second gas diffusion layers 14. It is preferable to be smaller. More preferably, the pore diameter of the boundary portion 14 b between the power generation region and the manifold region in the first and second gas diffusion layers 14 is a pore diameter through which liquid resin cannot pass, For example, it is 20 m or less. As a result, the liquid resin impregnated to form the manifold region at the boundary portion 14 can be prevented from entering the power generation region.

Further, the pore diameter in the power generation region portion 14 a of the first and second gas diffusion layers 14 is more than 2, and the pore diameter capable of ensuring gas flowability is selected. On the other hand

1. The pore diameter of the peripheral portion 14 c of the second gas diffusion layer 14 is also more than 20 m, and the pore diameter that can be impregnated with the liquid resin for forming the manifold is selected.

Next, as the electrolyte membrane in the above-mentioned joined body, for example, a fluorine-based membrane such as naphthion (Nafion; registered trademark, manufactured by DuPont) or a hydrocarbon-based membrane (HC membrane) can be used. The fuel electrode and air electrode are composed of an electrode catalyst supported on a carbon-based support. As an electrode catalyst, a catalyst made of platinum or a platinum-containing alloy, an alloy containing platinum, or even platinum can be contained. Examples of such metals include iron, cobalt, nickel, chromium, copper, and vanadium, and this electrode catalyst is supported on a carbon-based support.

As the first and second gas diffusion layers 14, for example, paper, cloth, high cushion paper, porous metal can be used, and a carbon particle layer formed of an aggregate of carbon particles having water repellency. It may be. Examples of carbon particles include carbon black, graphite, and expanded graphite. Carbon blacks such as oil furnace black, channel black, lamp black, thermal black, and acetylene black, which have excellent electronic conductivity and a large specific surface area. Can be suitably used. In addition, in order to prevent a flooding phenomenon or the like in the fuel cell, the first and second gas diffusion layers 14 are provided with a water repellent, and examples of the water repellent include polytetrafluoroethylene (PTFE). ), Polyvinylidene fluoride (PVDF), polyhexafluoropropylene, tetrafluoroethylene monohexafluoropro Examples include fluorine polymer materials such as pyrene copolymer (FEP), polypropylene, and polyethylene.

As the liquid resin for forming the gasket body 16, for example, a thermosetting silicone resin or a thermoplastic resin can be used.

In the present embodiment, the peripheral portion 14 c expanded to the manifold region in the first and second gas diffusion layers 14 is not provided with the water repellent and maintains the pore diameter, The affinity of the liquid resin to be impregnated may be improved. Second embodiment.

FIG. 2 shows the configuration of the membrane electrode assembly 10 B of the fuel cell according to the second embodiment. In the membrane electrode assembly 10 A in the first embodiment shown in FIG. 1 described above, only one gas diffusion layer 14 has its end extending to the manifold region. In the membrane electrode assembly 10 B according to the embodiment, the end portions of the first and second gas diffusion layers 14 extend to the manifold region and the peripheral edges of the first and second gas diffusion layers 14. The configuration of the membrane electrode assembly 10 B of the second embodiment is the same as the configuration of the membrane electrode assembly 1 OA of the first embodiment, except that the portions 14 c are formed so as not to overlap each other. Is the same.

In the first and second embodiments, the extended peripheral portions 14 c of the first and second gas diffusion layers 14 are formed so as not to overlap each other, but the electrolyte membrane is the same. If the film quality (not shown) is arranged between both diffusion layers and electrical insulation is ensured, the peripheral edges 14 c of both gas diffusion layers 14 may overlap each other. Good. Third embodiment.

FIG. 3 shows the configuration of the membrane electrode assembly 10 C of the fuel cell according to the third embodiment. In the membrane electrode assembly 1 OA in the first embodiment shown in FIG. 1 described above, the end portion of the assembly 12 extends beyond the power generation region to the boundary portion, but in the third embodiment, In the membrane electrode assembly 10 C, both ends of the assembly 12 extend beyond the boundary to the manifold region, respectively. The configuration of the membrane electrode assembly 10 C of the embodiment is the same as the configuration of the membrane electrode assembly 10 A of the first embodiment. Fourth embodiment.

FIG. 4 shows the configuration of the membrane electrode assembly 10 D of the fuel cell according to the fourth embodiment. In the membrane electrode assembly 10 B in the second embodiment shown in FIG. 2 described above, the end of the assembly 12 extends beyond the power generation region to the boundary portion. In the membrane electrode assembly 10 D of the fourth embodiment, the both ends of the assembly 12 extend beyond the boundary to the manifold region, respectively, except for the membrane electrode assembly 10 D of the fourth embodiment. The configuration is the same as that of the membrane electrode assembly 10 B of the second embodiment.

According to the third and fourth embodiments, the joined body 12 generally has a high affinity with a liquid resin that hermetically seals the manifold region, so that the joined body is extended to the manifold region. However, by adhering to the liquid resin, the adhesion reliability of the fuel cell is further ensured. Fifth embodiment.

Next, a fuel cell according to a fifth embodiment will be described with reference to FIG. The same components as those in the first, second, third, and fourth embodiments are denoted by the same reference numerals, and the description thereof is omitted.

As shown in FIG. 5, the fuel cell of the present embodiment includes a joined body 12 having a fuel electrode and an air electrode on an electrolyte membrane, and a fuel gas in each of the fuel electrode and the air electrode in the joined body 12. The first and second gas diffusion layers 14 for supplying the oxidant gas and the first and second porous flow path layers 24 and 4 stacked on the first and second gas diffusion layers 14 and 4 respectively. The membrane electrode assembly 2 OA consisting of is sandwiched by a pair of separators (not shown) described later. In the present embodiment, the first and second gas diffusion members of the present invention are porous channel layers.

Further, the fuel cell according to the present embodiment includes a power generation region in which the joined body 12 and the first and second gas diffusion layers 14 are stacked and capable of generating power, and is provided around the power generation region. And a manifold region formed with a manifold opening 18 through which fuel gas, oxidant gas and refrigerant are circulated, and either of the first and second porous channel layers 24. One of them extends to the manifold region, and one peripheral portion 24 c of the porous channel layer 24 is impregnated with a liquid resin and hermetically sealed. Further, an elastic gasket body 16 formed by curing a liquid resin is formed around the manifold opening portion 18, and the peripheral portion 24 c also functions as a core material of the gasket body 16. is doing. In the fuel cell according to the present embodiment, the porosity of the boundary portion 24 b between the power generation region and the manifold region in the first and second porous body flow path layers 24 described above is small. In both cases, the porosity of the power generation region 24 a in the first and second porous channel layers 24 and the porosity of the peripheral portion 24 c in the manifold region are relatively small. Further, the porosity of the boundary portion 24 b in the first and second porous channel layers 24 is equal to the peripheral portion 2 of the manifold region in the first and second porous channel layers 24. It is preferably less than the porosity of 4c. More preferably, the pore diameter of the boundary portion 24 b between the power generation region and the manifold region in the first and second porous body flow path layers 24 is such that liquid resin cannot pass through. The hole diameter is, for example, 20 / m or less. As a result, gas sealability is ensured at the boundary portion 24 b, and the liquid resin impregnated to form the manifold region can be prevented from entering the power generation region. In addition, the pore diameter in the power generation region 2 4 a of the first and second porous flow passage layers 24 is more than 20 // m, and the pore diameter can ensure gas flowability and drainage. Is selected. On the other hand, the pore diameter of the peripheral portion 24 c of the first and second porous channel layers 24 also exceeds 20 m, and the pore diameter that can be impregnated with the liquid resin for forming the manifold is large. Selected.

For the porous channel layer 24, for example, a lath cut metal or an expanded metal as shown in FIG. 11 can be used.

Here, in the present embodiment, the term “las cut metal” refers to a small net-like diameter by sequentially processing staggered cuts and bending the cuts on a flat thin metal plate. Through-holes are formed. In addition, “expanded metal” refers to a thin metal plate that has a mesh-like small diameter by processing cuts in a staggered arrangement on a flat thin metal plate and pressing and bending the cut cuts. A hole is formed, and further, rolled into a substantially flat plate shape. Since the expanded metal is formed in a substantially flat plate shape, for example, it is not necessary to provide a process for removing unnecessary bending or unevenness in the final molded product, and the manufacturing cost can be reduced.

Further, in the porous channel layer 24 of the present embodiment, when it also serves as a current collector, any metal material can be used as long as it is a metal separator used later. A material having a certain degree of rigidity that allows a predetermined gas flow against the pressure at the time of stacking and compressing the above-described cells during production is preferable, for example, titanium, stainless steel, and aluminum are preferable. When stainless steel or aluminum is used, it is preferable to perform surface treatment after groove processing and lath cut processing, which will be described later, if necessary, to impart corrosion resistance and electrical conductivity to the surface. Sixth embodiment.

FIG. 6 shows the configuration of the membrane electrode assembly 20 B of the fuel cell according to the sixth embodiment. In the membrane electrode assembly 2 OA in the fifth embodiment shown in FIG. 5 described above, only one porous channel layer 24 has its end extending to the manifold region. In the membrane electrode assembly 20 B according to the embodiment, the end portions of the first and second porous channel layers 24 extend to the manifold regions, respectively, and the first and second porous channel layers The configuration of the membrane / electrode assembly 20 B of the sixth embodiment is the same as that of the membrane / electrode assembly of the fifth embodiment, except that the peripheral edge portions 2 4 c of 24 are formed so as not to overlap each other. 2 Same as OA configuration.

In the fifth and sixth embodiments, the extended peripheral edge portions 24 c of the first and second porous channel layers 24 are formed so as not to overlap each other. In the case where the liquid resin impregnation property at 24 c is high and sufficiently gas-sealed, the peripheral portions 24 c of both the porous channel layers 24 may overlap each other. In these configurations, since the clearance between the porous body flow paths can be ensured by a thickness corresponding to the thickness of the MEA joined body 12, it is molded so that both do not come into contact with each other, or insulation treatment is applied to either one of the two hole portions in advance. If applied, membranes and films are not always necessary. Seventh embodiment.

FIG. 7 shows the configuration of the membrane electrode assembly 20 C of the fuel cell in the seventh embodiment. Membrane electrode assembly in the fifth embodiment shown in FIG. 5 described above

In 2 O A, the end of the joined body 12 extends beyond the power generation region and extends only to the boundary portion, but in the membrane electrode assembly 20 C of the fuel cell in the seventh embodiment, the joined body

The structure of the fuel cell cell electrode assembly 20 C in the seventh embodiment is the same as that of the fifth embodiment except that both ends of 12 extend beyond the boundary to the manifold region. The configuration of the membrane electrode assembly 2 OA in the form is the same. Eighth embodiment.

FIG. 8 shows the configuration of the membrane electrode assembly 20 D of the fuel cell according to the eighth embodiment. In the membrane electrode assembly 20 B in the sixth embodiment shown in FIG. 6 described above, the end of the assembly 12 extends beyond the power generation region to the boundary portion. In the fuel cell membrane electrode assembly 20 D, both ends of the assembly 12 extend beyond the boundary to the manifold region, respectively, except for the fuel cell cell according to the eighth embodiment. The configuration of the membrane electrode assembly 20 D is the same as the configuration of the membrane electrode assembly 20 B in the sixth embodiment.

According to the seventh and eighth embodiments, the joined body 12 generally has a high affinity with the liquid resin that hermetically seals the manifold region, so that the joined body is extended to the manifold region. However, by adhering to the liquid resin, the adhesion reliability of the fuel cell is further ensured. Ninth embodiment.

Next, a fuel cell according to a ninth embodiment will be described with reference to FIG. The same components as those in the first to eighth embodiments are denoted by the same reference numerals, and the description thereof is omitted.

In the present embodiment, as shown in FIG. 9, the peripheral edge portions 24 c of the first and second porous channel layers 24 A and 24 B overlap each other in the manifold region. Rather, they are stretched in different directions. And as shown in Fig. 9, Position the pre-membrane electrode assembly in which the joined body 12 and the gas diffusion layer 14 are formed on both sides of the power generation region 2 4 a of the second porous body flow path layer 2 4 A and 2 4 B. The membrane electrode assembly 30 is formed by sandwiching the pre-membrane electrode assembly with the first and second porous channel layers 24 A and 24 B. The cross-sectional structure of the membrane electrode assembly 30 of the present embodiment is the same as the configuration of the membrane electrode assembly 2 OA shown in FIG. According to the present embodiment, since the first and second porous body flow passage layers 2 4 A and 2 4 B on the anode side and the force sword side are formed as described above, between the anode and the force sword Short circuit and gas leak can be prevented and productivity is improved. Each of the first and second porous channel layers 24 A and 24 B may be a force sword side and an anode side opposite to those described above.

Further, for example, when a rascut metal is used as the first and second porous channel layers 24 A and 24 B as described above, the rascut device 50 shown in FIG. 12 is used. can do.

The lath cutting device 50 shown in Fig. 1 has a lath cutting blade 5 2 a and a fixed blade 5 2 b which are vertically operated on the end side to which the metal plate 26 to be lascated is fed. Is provided. The fixed blade 5 2 b is fixed to the end side to which the metal plate 26 of the lath cut device 50 is fed, and further, the cut blade is formed on the outer side of the fixed blade 5 2 b. Has been. Therefore, the porosity of each region of the lascut metal can be changed by adjusting the feed amount of the metal plate 26 of the lascut device 50 and the lowering amount of the cutting rascut blade 52a. That is, taking the porous channel layer 24 A shown in FIG. 9 as an example, first, when forming the peripheral portion 24 c, for example, the pore diameter exceeds 20 m; When adjusting the feed amount of the metal plate 26 and the lowering amount of the cutting blade 5 2 a so that the opening ratio becomes possible, and then forming the boundary portion 2 4 b, for example, the pore diameter 20 tm When adjusting the feed amount of the metal plate 26 and the descending amount of the cutting lascutter blade 5 2 a so as to be as follows, and further forming the power generation region portion 2 4 a, for example, the pore diameter 20 / m It is formed by adjusting the feed amount of the metal plate 26 and the cutting amount of the cutting blade 5 2 a so that the opening ratio can be exceeded and the gas flowability and drainage performance can be secured, and the boundary 2 4 b, peripheral edge 2 4 c with variable aperture ratio as above As a result, a porous channel layer 24 A including regions having different porosities can be formed. In the region of the boundary portion 24 b, the metal plate 26 is fed and the lath force cutting process is not performed, so that it is possible to have a configuration in which there is substantially no pore.

In the present embodiment, the direction of the lascuit ridges of the porous body flow path layers 24 A and 24 B having regions with different porosities is one direction, but the present invention is not limited to this. At 50, a power generation region portion 24 a and a lass cut metal having boundary portions 24 b formed at both ends thereof and a lass cut plate having a pair of peripheral portions 24 c are separately manufactured. These two kinds of lascut metal may be joined so as to have different lascut directions (for example, welding) to form porous channel layers 24 A and 24 B. 10th embodiment.

Next, the fuel cell according to the tenth embodiment will be described with reference to FIG. The same components as those in the first to ninth embodiments are denoted by the same reference numerals, and the description thereof is omitted.

In the present embodiment, as shown in FIG. 10, when the gasket body 16 is formed by impregnating the liquid resin at the end of the peripheral edge portion 24 c of one porous body flow path layer 24, the peripheral edge The peripheral edge portion 2 4 c is deformed in advance so that the end portion of the portion 24 c is positioned at the center of the gasket body 16 in the thickness direction. The peripheral edge portion 2 4 c of the porous channel layer 2 4 located in the center functions as a reinforcing layer, and the gasket body 1 6 against the pressure applied to the gasket body 1 6 from above and below when stacking unit cells. As a result, the distortion of the gasket 16 due to the pressure can be suppressed. This further improves the gas sealing performance of the fuel cell when unit cells are stacked.

In FIG. 10, the peripheral portion 2 4 c of the porous body flow path layer 24 is deformed to form the reinforcing layer of the gas casing 16, but the present invention is not limited to this. For example, gas diffusion as shown in FIG. The peripheral edge portion 14 c of the layer 14 may be deformed to form a reinforcing layer. The thickness of the porous body flow path layer 24 formed of lascut metal or the like is, for example, 0.2 mm to 0.2 mm. Since the thickness of the gas diffusion layer 14 shown in FIG. 1 is 3 mm, which is thicker than, for example, 100 m to 280 m, it is suitable as a reinforcing layer. Further, when the porous body flow path layer 24 is formed of a lath cut metal, the above-described deformed peripheral portion is deformed by further bending at the start point and the end point during the lath cutting process in the lath cut apparatus 50 (FIG. 12). 24 c can be formed. An example of a method for integrally forming a membrane electrode assembly by impregnating a liquid resin in the first to tenth embodiments will be described with reference to FIG. FIG. 13 shows an example of injection molding using a mold, for example, liquid injection molding (LIM) molding. As the LIM material 60 described later, a thermosetting silicone resin or a thermoplastic resin can be used, and the membrane electrode assemblies 10 A to 10 L in the first to tenth embodiments: L 0 D , 20A to 20D, 30, and 40 are collectively referred to herein as “membrane electrode assembly 70” for convenience of explanation.

First, the LIM material 60 made of the above-mentioned material for gasket formation, for example, is weighed in the injection unit 54, and the peripheral edge of the membrane electrode assembly 70 is fixed by the fixture 62, so that the membrane electrode assembly 70 is made of gold. After installing in the mold, the inside of the mold is decompressed through the decompression pipe 58, and the air in the mold is removed (S 1 1 0). Next, when the pressure inside the mold reaches a desired reduced pressure state, the pressure reducing operation is stopped, the piston 55 of the injection unit 54 is operated, and the gasket forming metal is injected via the injection pipes 56, 56a, 56b. The mold parts 80a and 80b are each filled with LIM material 60 (S120). Next, after the injection filling of the L I M material 60 into the gasket forming mold parts 80a and 80b is completed, the L I M material 60 is heated and cured (S130). As a result, a gasket type membrane electrode assembly is formed. Next, Fig. 14 shows an example of the unit cell structure. In the unit cell shown in FIG. 14, the membrane electrode assembly 2 OA shown in FIG. 5 is sandwiched between a pair of flat separators 22. Here, the flat separator evening 22 has a smooth surface on the side of the membrane electrode assembly 2 OA (FIG. 5).

In recent years, metal separators have come to be used as fuel cell separators from the standpoint of durability, but these metal separators are both corrosion resistant and conductive. Standing is essential. Titanium separators are listed as candidates for achieving both the above corrosion resistance and conductivity. However, since titanium has high rigidity and is not easy to press like stainless steel, the flow path must be formed by a method other than pressing. Therefore, a configuration has been devised in which the titanium separator is a flat separator and a flow path is formed by a porous body between the flat separator and the gas diffusion layer. Alternatively, expanded metal is used as the pseudo porous channel layer.

In the above unit cell, the membrane electrode assembly 2 OA shown in FIG. 5 has been described. However, the present invention is not limited to this, and the membrane electrode assembly 20 B, 30 shown in FIG. 6, FIG. 9, and FIG. , 40 may be used.

Another example of the unit cell structure is shown in FIG. In the unit cell shown in FIG. 15, the membrane electrode assembly 20 C shown in FIG. 7 is sandwiched between a pair of flash separators 22. Here, in the flat separator evening 22, the surface on the side of the membrane electrode assembly 20 C (FIG. 7) is a smooth surface. In the unit cell, the membrane electrode assembly 20 C shown in FIG. 7 has been described. However, the present invention is not limited to this, and the membrane electrode assembly 20 D shown in FIG. 8 may be used.

An example of another unit cell structure is shown in Fig.16. In the unit cell shown in FIG. 16, the membrane electrode assembly 1 O A shown in FIG. 1 is sandwiched between a pair of separators 28. In the pair of separators 28, a reaction gas channel 34 is formed, and a refrigerant channel (not shown) is formed on the opposite side of the surface on which the reaction gas channel 34 is formed. For example, the separator overnight 28 is made of a metal material such as stainless steel or aluminum.

The other unit cell has been described using the membrane electrode assembly 1 OA shown in FIG. 1. However, the present invention is not limited to this, and the membrane electrode assembly 10 B shown in FIG. 2 may be used. Another example of the unit cell structure is shown in Fig. 17. In the unit cell shown in FIG. 17, the membrane electrode assembly 10 C shown in FIG. 3 is sandwiched between a pair of flat separators 22. Here, in the flat separator overnight 22, the surface on the side of the membrane electrode assembly 10 C (FIG. 3) is a smooth surface. In the unit cell, the membrane electrode assembly 10 C shown in FIG. 3 is used, but the present invention is not limited to this, and the membrane electrode assembly 10 D shown in FIG. 4 is used. May be.

In addition, the boundary between the porous channel layers 2 4, 2 4 A, 24 B in the membrane electrode assemblies 20 A to 20 D, 30, 40 of the fifth to 10th embodiments described above The parts 2 4 e and 24 f may be sealed in advance as shown in FIGS. 18A and 18B. As a result, when molding the gasket, it is possible to prevent the porous channel layers 24, 24 A, 24 B from being impregnated with liquid resin more than necessary, and to secure an effective electrode area. be able to. In the case of sealing, the boundary portion 24 e may be formed by pressing, or the boundary portion 24 f may be formed by impregnating another resin in advance by brazing, welding, screen printing, or the like. Good. Also on the side of the porous channel layer where the manifold opening is not formed, as described above, a sealing portion is formed by impregnation with another resin in advance by pressing, brazing, welding, screen printing, or the like. It is desirable. Thereby, it is possible to prevent the liquid resin from being impregnated more than necessary, and to secure an effective electrode area.

Further, the unit cells described above are stacked to form a fuel cell. As a result, since the cells with the reduced number of parts are stacked, the fuel cell can be reduced in size, the gas sealing performance can be improved, and the power generation efficiency per fuel cell can also be improved. Although the present invention has been described in detail, the scope of the present invention is not limited to that described above. In addition, the Japanese Patent Application filed on August 10th, 2000, 2000, 2 0 0 7—2 0 9 0 6 2, 2 0 0 7 -3 1 5 7 3 7 Detailed description of the invention, claims, drawings and abstract are all incorporated in the present application. Industrial applicability

The fuel cell and the fuel cell of the present invention are effective for any use as long as the fuel cell is used, but can be used for a fuel cell for vehicles in particular.

Claims

The scope of the claims

1. a joined body having a fuel electrode and an air electrode on an electrolyte membrane; a first gas diffusion member that supplies fuel gas to the fuel electrode; and a second gas diffusion that supplies oxidant gas to the air electrode A fuel cell unit comprising: a member; and a pair of separators sandwiching the first gas diffusion member, the joined body, and the second diffusion member,

A power generation region where the joined body is located; and a manifold region provided around the power generation region and formed with a manifold opening through which fuel gas, oxidant gas and refrigerant are circulated.

At least one of the first gas diffusion member or the second gas diffusion member extends to the manifold region and is impregnated with a liquid resin and hermetically sealed, and the first gas diffusion member and the first gas diffusion member The porosity of the boundary between the power generation region and the manifold region in the second gas diffusion member is at least the porosity of the power generation region and the manifold region in the first gas diffusion member and the second gas diffusion member A fuel cell that is relatively small compared to the rate.

2. In the fuel cell according to claim 1,

Either the first gas diffusion member or the second gas diffusion member extends to the manifold region and is impregnated with a liquid resin and hermetically sealed.

3. In the fuel cell according to claim 1,

The porosity of the boundary between the power generation region and the manifold region in the first gas diffusion member and the second gas diffusion member is the same as in the first gas diffusion member and the second gas diffusion member. Fuel cell smaller than the porosity of the manifold area. \

WO 2009/028331 PCT / JP2008 / 064502

twenty one

4. In the fuel cell according to claim 2,

The porosity of the boundary between the power generation region and the manifold region in the first gas diffusion member and the second gas diffusion member is the same as in the first gas diffusion member and the second gas diffusion member. Fuel cell smaller than the porosity of the manifold area.

5. In the fuel cell according to claim 1,

Furthermore, the joined body is bonded to a liquid resin that extends to the manifold region and seals hermetically.

6. In the fuel cell according to claim 2,

7. In the fuel cell according to claim 3,

8. In the fuel cell cell according to claim 4,

Furthermore, the joined body is bonded to a liquid resin that extends to the manifold region and is airtight.

9. In the fuel cell according to claim 1,

The fuel cell according to claim 1, wherein the first diffusion member and the second diffusion member are gas diffusion layers provided on the fuel electrode and the air electrode, respectively.

1 0. In the fuel cell according to claim 1,

The separation evening is a flat separation evening where the joined body side surface is a smooth surface,

The first diffusion member and the second diffusion member are porous flow passage layers respectively disposed between the gas diffusion layers provided in the fuel electrode and the air electrode, respectively, and the flat separator. Fuel cell.

1 1. In the fuel cell according to claim 1,

A fuel cell having a pore diameter of 20 m or less at a boundary portion between the first gas diffusion member and the second gas diffusion member.

1 2. In the fuel cell according to claim 10,

The porous body flow path layer is a fuel cell that is made of a lath metal or expanded metal having different porosity at the boundary between the power generation region, the manifold region, and the power generation region and the manifold region.

1 3. In the fuel cell according to claim 1,

The manifold is provided with a gasket that integrates the first gas diffusion member, the joined body, and the second diffusion member and hermetically seals the periphery of the manifold opening. ,

The peripheral portion of the first gas diffusion member or the second gas diffusion member, which is enlarged in the manifold region, is located at the center in the thickness direction of the gasket.

14. A fuel cell comprising the fuel cell according to claim 1 stacked thereon.

1 5. A fuel cell obtained by stacking the fuel cell cells according to claim 2.

16. A fuel cell in which the fuel cell cells according to claim 3 are stacked.

1 7. A fuel cell comprising the fuel cell according to claim 5 stacked thereon.