Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
2001-01-29
2003-04-08
Lieu, Julie (Department: 2632)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S438000, C210S638000, C210S650000
Reexamination Certificate
active
06545609
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a humidification system for a fuel cell. More specifically, the present invention relates to a humidification system provided with a fuel cell which has been adapted as an energy source for a vehicle, such as an electric vehicle.
2. Description of Related Art
Recently, a vehicle, such as an electric vehicle, which utilizes a “clean energy”, such as a solid polymer type fuel cell, has been developed. The Japanese Unexamined Patent Application, First Publication No. 6-132038, for instance, discloses a solid polymer electrolyte type fuel cell which may be used for such an energy source.
In general, a solid polymer type fuel cell that is used for such vehicles has a laminate structure in which a power generating element is supported by gas separating members from both sides thereof. In the laminate structure, a plurality of gas passageways for supplying a reaction gas is formed on a power generating element which is formed by a hydrogen ion conductive solid polymer being sandwiched by a pair of carbon electrodes carrying platinum catalyst (i.e., a solid polymer electrolyte membrane—electrode joined unit) and each electrode surface.
When the above-mentioned solid polymer type fuel cell is used, hydrogen gas is supplied to one of the electrodes as a fuel supply gas and oxygen or air is supplied to the other electrode as a supply gas for an oxidizing agent. In such a manner, electricity is extracted directly from chemical energy obtained by an oxidation reduction reaction of the fuel supply gas.
That is, the electric energy is taken out of the series of electrochemical reactions in which the hydrogen gas is ionized at the anode side to move in the solid polymer electrolyte and the electrons are moved toward the cathode side via an external load to react with the oxygen to produce water.
In the above-mentioned fuel cell, if the solid polymer electrolyte membrane is dried out, the efficiency in the ion conductivity thereof is decreased. Accordingly, the efficiency in the energy conversion is also decreased. Therefore, it is necessary to supply water to the solid polymer electrolyte membrane so that an excellent ion conductivity thereof may be maintained.
For this reason, a humidification device is provided with a fuel cell of the above type, which is capable of humidifying supply gas, such as a fuel supply gas and a supply gas for an oxidizing agent, and supplying water to the solid polymer electrolyte membrane so that an excellent reaction of at the membrane may be maintained.
The structure of an example of the humidification device will be explained with reference to FIG.
10
. In
FIG. 10
, a humidification device is indicated by a numeral 1. In the humidification device
1
, outside air which is pressurized by a super charger
2
is supplied to a supply gas line
5
as a supply gas for an oxidizing agent and the supply gas is humidified by the humidification device
1
. The humidified air is then supplied to a fuel cell (hereinafter referred to as a stack)
3
and the oxygen contained in the humidified air is used as an oxidizing agent. After that, the gas is emitted as a discharge gas.
Also, the discharge gas containing water which is generated when reacted in the stack
3
is supplied to the humidification device
1
, via a discharge gas line
6
, from the stack
3
. The water vapor contained in the discharge gas is transferred to the supply gas in the humidification device
1
and then evacuated.
As shown in
FIG. 4
, a pressure regulating valve
4
which regulates the inner pressure of the stack
3
is provided with the discharge gas line
6
.
A humidifier
11
as shown in
FIGS. 11 and 12
is disposed in the humidification device
1
.
The humidifier
11
is formed by a plurality of tube type porous hollow thread members
12
which are made of a vapor permeable membrane (i.e., a water permeable membrane). The plurality of tube type porous hollow thread members
12
are contained in a cylidrically shaped casing
14
which has a plurality of opening portions
13
formed around its peripheral surface in the proximity to both ends thereof. The outer surfaces of the hollow thread members
12
as well as the outer surface of the hollow thread member
12
and the inner surface of the casing
14
are sealed at both ends of the casing
14
.
In the humidifier
11
, the supply gas is supplied from the opening portions
13
located in the proximity to one of the two ends of the casing
14
. The supply gas is passed through the gap present between each of the hollow thread members
12
and exited from the opening portions
13
located in the proximity to the other end of the casing
14
. Also, the discharge gas supplied from the stack
3
is supplied to the hollow thread members
12
from one end of the casing and exited from the other end.
As shown in
FIG. 13
, the hollow thread member
12
has numerous capillary portions
15
and the vapor contained in the discharge gas, which is introduced to the hollow thread members
12
, is condensed in the capillary portions
15
and moved toward an outer periphery side thereof. The condensed vapor is then evaporated into the supply gas.
That is, the water content of the discharge gas is transferred to the supply gas in the humidifier
11
so that the humidification of the supplied gas is performed.
However, since extremely thin threads having an inner diameter of, for instance, about 0.3 mm (cf. the capillary portion size is about 4 nm) are used as the hollow thread members
12
in the humidifier
11
, there is a danger that the capillaries of the hollow thread members
12
may be blocked by dust contained in the discharge gas which is supplied from the stack
3
. Also, since the hollow thread members
12
used in the humidifier
11
are bundled and the supply gas is passed through between each of the hollow thread members
12
, there is a danger that the gap between each of the hollow thread members
12
may also be blocked by dust which may be contained in the supply gas.
If the capillaries of the hollow thread members
12
or the gap between each of the hollow thread members
12
is blocked, a transfer of the vapor contained in the discharge gas to the supply gas cannot be satisfactorily carried out and, hence, a sufficient amount of water cannot be supplied to the stack
3
. Thus, the efficiency in power generation of the stack
3
is decreased and this may lead to a cause of the failure of the stack
3
.
SUMMARY OF THE INVENTION
Accordingly, one of the objectives of the present invention is to provide a humidification system for a fuel cell which does not have the above-mentioned problems.
Another objective of the present invention is to provide a humidification system for a fuel cell which is capable of quickly detecting a clogging in a humidifier so that the affect to a stack caused by the decrease in humidification of a supply gas due to the clogging in the humidifier may be suppressed to a minimal level.
The above objectives may be achieved by a humidification system for a fuel cell according to the present invention, including: a humidifier having a bundled plurality of tube type hollow thread members made of a water-permeable membrane, the humidifier transferring a water content contained in a discharge gas, which is emitted from a fuel cell, to a supply gas, which is supplied to the fuel cell, when one of the discharge gas and the supply gas is passed through the inside of the tube type hollow thread members and the other one of the discharge gas and the supply gas is passed through between the tube type hollow thread members; and a detection device which detects a generation of clogging in or between the tube type hollow thread members.
According to the above humidification system, since the detection device which is capable of detecting clogging is provided with the humidifier which humidifies the supply gas by transferring water vapor contained in the discharge gas to the supply gas by means of the water-permeable membrane that forms the bundled p
Katagiri Toshikatsu
Kusano Yoshio
Shimanuki Hiroshi
Suzuki Motohiro
Honda Giken Kogyo Kabushiki Kaisha
Lahive & Cockfield LLP
Lieu Julie
LandOfFree
Humidification system for fuel cell does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Humidification system for fuel cell, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Humidification system for fuel cell will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3047826