Separator for fuel cell, method of producing the separator, and method of assembling the fuel cell

Abstract

A fuel cell includes first and second separators sandwiching a membrane electrode assembly. The first and second separators include first and second metal plates, first and second insulating bushings for positioning the first and second metal plates in alignment with each other, and first and second seal members formed integrally with the first and second metal plates. The first and second seal members are formed by injection molding on the first and second metal plates using the first and second insulating bushings as insert members.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view schematically showing structure of a fuel cell stack formed by stacking fuel cells according to an embodiment of the present invention;

FIG. 2 is an exploded perspective view showing the fuel cell;

FIG. 3 is a front view showing a first separator of the fuel cell;

FIG. 4 is an enlarged cross sectional view showing main components of the fuel cell;

FIG. 5 is a view showing a state in which an insulating bushing is provided on a metal plate;

FIG. 6 is a view showing a state in which the metal plate is placed in a molding die and one of cavities is formed;

FIG. 7 is a view showing a state in which the metal plate is placed in the molding die and the other of the cavities is formed;

FIG. 8 is a view showing a state in which a seal member is formed on the metal plate;

FIG. 9 is a view showing a state in which another seal member is formed on the metal plate; and

FIG. 10 is an exploded perspective view showing main components of a conventional fuel cell.

Claims

1. A separator for a fuel cell comprising an electrolyte electrode assembly including a pair of electrodes and an electrolyte interposed between said electrodes, said separator being stacked on said electrolyte electrode assembly, and comprising: a metal plate;a positioning member for positioning said metal plate and another metal plate that are stacked together in a stacking direction; anda seal member formed integrally with said metal plate,wherein said seal member is formed on said metal plate by injection molding using said positioning member as an insert member.

2. A separator according to claim 1, wherein said positioning member is at least partially embedded under said seal member such that said positioning member is held by said metal plate.

3. A separator according to claim 2, wherein said positioning member comprises: an expansion fitted to a positioning hole of said metal plate; anda flange which contacts metal exposed surface of said metal plate and which is at least partially embedded under said seal member.

4. A method of producing a separator for a fuel cell comprising an electrolyte electrode assembly including a pair of electrodes and an electrolyte interposed between said electrodes, said separator being stacked on said electrolyte electrode assembly, said method comprising the steps of: providing a positioning member for positioning metal plates that are stacked together in a stacking direction, in a molding die as an insert member such that said positioning member is placed in a positioning hole of at least one of said metal plates; andinjecting melted resin in said molding die for forming a seal member integrally with said metal plate to obtain said separator.

5. A method according to claim 4, wherein said positioning member is at least partially embedded under said seal member such that said positioning member is held by said metal plate.

6. A method according to claim 5, wherein an expansion of said positioning member is fitted to said positioning hole of said meta plate, and a flange of said positioning member is at least partially embedded under said seal member such that said flange contacts a metal exposed surface of said metal plate.

7. A method of assembling a fuel cell by stacking first and second separators on both sides of electrolyte electrode assembly including a pair of electrodes, and an electrolyte interposed between said electrodes, the method comprising the steps of: providing first and second positioning members for positioning first and second metal plates that are stacked together in a stacking direction, in a molding die as insert members such that said first and second positioning members are placed in first and second positioning holes of said first and second metal plates;injecting melted resin in said molding die for forming first and second seal members integrally with said first and second metal plates to obtain said first and second separators; andproviding said electrolyte electrode assembly between said first and second separators, and fitting said first positioning member and said second positioning member to each other for positioning said first and second separators relative to each other to obtain said fuel cell.

8. A method according to claim 7, wherein said first and second positioning members are at least partially embedded under said first and second seal members such that said first and second positioning members are held by said first and second metal plates.

9. A method according to claim 8, wherein expansions of said first and second positioning members are fitted to said first and second positioning holes of said first and second metal plates, and flanges of said first and second positioning members are at least partially embedded under said first and second seal members such that said flanges contact metal exposed surfaces of said first and second metal plates.