Chemistry: electrical current producing apparatus – product – and – With pressure equalizing means for liquid immersion operation
Reexamination Certificate
2001-09-04
2004-01-13
Gulakowski, Randy (Department: 1746)
Chemistry: electrical current producing apparatus, product, and
With pressure equalizing means for liquid immersion operation
C429S006000, C429S006000, C429S006000
Reexamination Certificate
active
06677072
ABSTRACT:
RELATED APPLICATIONS
This application claims priority to Japanese Patent Application No. P2000-267765 filed on Sep. 4, 2000 in Japan, and Japanese Patent Application No. P2000-314315 filed on Oct. 13, 2000 in Japan. The contents of the aforementioned applications are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fuel cell where an electrode film structure comprising a solid polymer electrolyte film with an anode electrode and a cathode electrode on the opposite sides thereof is clamped with a pair of separators. More specifically, the present invention relates to a fuel cell where assembly and sealability between the electrodes and the separators is improved.
2. Description of the Related Art
For example, there has been developed a solid polymer electrolyte type fuel cell constituted by laminating a plurality of units, with one unit being such that an electrode film structure provided with an anode electrode and a cathode electrode at opposite positions with a solid polymer electrolyte film inserted therebetween is clamped by separators, and this has been utilized for various practical applications.
One example of this fuel cell will be described with reference to FIG.
23
. In this figure, reference symbol
1
denotes a solid polymer electrolyte film, and on opposite sides of this solid polymer electrolyte film
1
, there are respectively arranged an anode electrode
2
and a cathode electrode
3
, having a smaller area than that of the solid polymer electrolyte film
1
. Sealing members
4
and
5
for gas seal are arranged on the respective outer peripheral portions of the anode electrode
2
and the cathode electrode
3
.
The above sealing members
4
and
5
have seal lips
6
provided integrally and protrudingly on respective surfaces opposite to the surface contacting with the solid polymer electrolyte film
1
, so as to surround the electrode surface of the anode electrode
2
and the cathode electrode
3
.
A separator
8
exhibiting a fuel gas supply function and a power collecting function, and having guide grooves
7
for the fuel gas is arranged on the outside of the anode electrode
2
facing the anode electrode
2
, so as to come in contact with the anode electrode
2
. Likewise, a separator
10
exhibiting an oxidant gas supply function and a power collecting function and having guide grooves
9
for the oxidant gas is arranged on the outside of the cathode electrode
3
facing the cathode electrode
3
, so as to come in contact with the cathode electrode
3
.
The thus constructed fuel cells are laminated in a plurality of numbers, and the laminated body is fastened in the lamination direction by a fastening device (not shown) to thereby constitute a fuel cell as a stack.
In the above described fuel cell, differences in thickness between the anode electrode
2
and cathode electrode
3
, and the sealing members
4
and
5
can be absorbed by the seal lip
6
. As a result, the anode electrode
2
and the separator
8
, and the cathode electrode
3
and the separator
10
can be brought into good contact with each other, and hence this feature is excellent in contributing to the improvement of the cell performance (see Japanese Patent No. 2922132).
In the above described prior art however, there is a problem in that it is difficult to set the sealing members
4
and
5
and the anode electrode
2
and the cathode electrode
3
without causing misalignment, at the stage of superimposing the sealing members
4
and
5
on the solid polymer electrolyte film
1
. If misalignment occurs between the sealing member
4
on the anode electrode
2
side and the sealing member
5
on the cathode electrode
3
side in the direction along the surface of the solid polymer electrolyte film
1
, the positions where the seal lips
6
come close to the separators
8
and
10
shift slightly. As a result, the reaction force for the seal by the seal lips
6
acting on the solid polymer electrolyte film
1
on the base side of the seal lips
6
is biased, and hence an unbalanced force acts on the solid polymer electrolyte film
1
, thereby causing problems such as the solid polymer electrolyte film
1
slips or folds occur therein. As a result, a problem occurs in that the dimensional accuracy at the time of assembling the anode electrode
2
and the sealing member
4
, and the cathode electrode
3
and the sealing member
5
must be strictly controlled, thereby making production difficult.
Also in the solid polymer electrolyte type fuel cell, even if the solid polymer electrolyte film
1
, the anode electrode
2
and the cathode electrode
3
are overlapped, since these are as thin as several hundreds microns in the thickness direction, a sufficient height dimension for the seal lips
6
, that is, sufficient elastic deformation cannot be ensured, thereby causing a problem in the sealability.
Moreover, if the margin for compression of the seal lip
6
is increased so as to ensure the sealability, the fastening force in a condition with the fuel cells laminated increases, thereby causing an increase in size of the fastening member, an increase in size of the fastening apparatus, and a problem in that the separators
8
and
10
cannot endure the fastening force and may be damaged.
On the other hand, there is a case where a seal structure is adopted in which a groove is formed in the separator, the sealing members are set stably in the groove without causing misalignment, and the sealing member is closely contacted with the corresponding portion. FIG.
24
and
FIG. 25
show this example, wherein a seal S having a seal body having a square shape in cross-section is inserted into a groove
11
in the separators
8
and
10
. The seal S has a fin F at a corner thereof, and the insertion stability of the seal S is ensured by this fin F. Therefore, at the time of inserting the seal S into the groove
11
, the seal S can be inserted with torsion of the seal S being kept to a minimum.
FIG. 24
shows a case where the fin F is provided on the both sides, and
FIG. 25
shows a case where the fin F is provided on one side.
In such a structure however, in either case of the seal S shown in FIG.
24
and
FIG. 25
, when the seal S is inclined, the seal height decreases from H1 to H2, and the load applied to the seal S causes displacement in the direction of compression, as shown by the arrows in the figure, and a moment load acts thereon. As a result, the reaction force for the seal differs depending on the place, causing a problem in that uniform sealability cannot be obtained.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a fuel cell for which assembly of the seals is facilitated and with excellent sealability, and which enables miniaturization.
In order to solve the above problems, the invention according to a first aspect is characterized by a fuel cell (for example, a fuel cell N in this embodiment) where an electrode film structure (for example, an electrode film structure
12
in this embodiment) having an anode electrode (for example, an anode electrode A in this embodiment) provided on one side of a solid polymer electrolyte film (for example, a solid polymer electrolyte film
15
in this embodiment), and a cathode electrode (for example, a cathode electrode C in this embodiment) provided on the other side thereof is clamped with a pair of separators (for example, a separator
13
on the anode side and a separator
14
on the cathode side in this embodiment), wherein a groove (for example, a groove
38
in this embodiment) is provided on a separator surface corresponding to the outer peripheral portion of the anode electrode or the cathode electrode (for example, surfaces
13
a
,
14
a
in this embodiment), and a seal (for example, a seal S
1
in this embodiment) having a circular shape in cross-section and with a fin (for example, a fin F in this embodiment) is provided in this groove.
By having such a construction, it becomes possible to set a high seal height for the s
Inoue Masajiro
Kimura Nobuaki
Suenaga Toshihiko
Gulakowski Randy
Honda Giken Kogyo Kabushiki Kaisha
Lahive & Cockfield LLP
Scaltrito Don
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