JP2004199897A - Air supply device for fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the entrance of fine dust in the air and decrease pressure loss in a fuel cell. <P>SOLUTION: An air supply device 1 is equipped with a fuel cell 2 generating electric power by supplying air acting as an oxidizing agent to a cathode 2c and hydrogen gas to an anode 2b; an air supply passage 6 through which air is supplied to the cathode 2c of the fuel cell 2; and an air purifying device 10 installed in the air supply passage 6, and the air purifying device 10 has an electrostatic collector removing charged dust and a filter. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fuel cell air supply device.
[0002]
[Prior art]
As a fuel cell mounted on a fuel cell vehicle or the like, for example, a polymer electrolyte fuel cell (PEMFC) is known. This fuel cell is composed of a stack formed by stacking a plurality of cells formed by sandwiching a solid polymer electrolyte membrane between an anode electrode and a cathode electrode, and supplying a fuel gas (for example, hydrogen gas) to the anode electrode. Then, power is generated by supplying an oxidizing gas to the cathode electrode. This generated power is supplied to a drive motor of a fuel cell vehicle, and to auxiliary equipment necessary for operating the fuel cell (for example, an air compressor that supplies air to the fuel cell, a water pump that circulates cooling water, and the like).
In this fuel cell, oxygen in the air is generally used as an oxidizing gas, and air is taken in from the atmosphere and pumped to the fuel cell. By the way, since dust is contained in the atmosphere, it is necessary to remove dust in the air before supplying the dust to the cathode electrode of the fuel cell. Conventionally, dust has been removed by a filtration type filter (for example, And Patent Document 1).
[0003]
[Patent Document 1]
JP-A-7-94200
[Problems to be solved by the invention]
However, due to the structure of the fuel cell, the air supplied to the fuel cell has a slow flow rate at the cathode electrode. Therefore, when air containing fine dust is supplied, the fine dust adheres to the cathode electrode and becomes clogged. This may cause a decrease in the supply amount of oxygen, a decrease in the reaction area, and a decrease in output of the fuel cell. In particular, it has been experimentally confirmed that silica present in air is fine and easily adheres to the cathode electrode.
In order to avoid such a situation, the filter should be made finer so that fine dust can be removed.However, the finer filter increases the pressure loss, so a large output is also required for the compressor. As a result, the energy (parasitic power) required to operate the fuel cell increases, and the energy efficiency decreases.
[0005]
There is also a method of reducing the thickness of the filter in order to reduce the pressure loss of the filter, but a large amount of air supply is required, and the durability of the filter is insufficient in a fuel cell in which the supply flow rate changes. There is a concern.
Therefore, the present invention provides an air supply device for a fuel cell, which has a small pressure loss, can remove fine dust, and has high energy efficiency.
[0006]
[Means for Solving the Problems]
In order to solve the above problem, the invention according to claim 1 is directed to a method in which air as an oxidant is supplied to a cathode electrode (for example, a cathode electrode 2c in an embodiment described later) and an anode electrode (for example, an embodiment described later). A fuel cell (for example, a fuel cell 2 in an embodiment described later) in which a fuel gas is supplied to an anode electrode 2b) to generate electric power, and an air supply path (for example, to be described later) for supplying air to a cathode electrode of the fuel cell And an electrostatic trap which is provided in the air supply path and has a polarity opposite to that of the dust to be collected to collect the dust. Means (for example, an electrostatic collection device 20 in an embodiment to be described later). Feeder 1).
With this configuration, fine dust having a charge contained in the atmosphere, such as silica, can be removed by the electrostatic collection means. Further, since the electrostatic collection means has a small pressure loss, energy (parasitic power) required for supplying air to the fuel cell can be small.
[0007]
According to a second aspect of the present invention, in the first aspect of the present invention, the electrostatic collection unit is in contact with a friction body (for example, friction bodies 24 and 31 in an embodiment described later). An electrostatic collector (for example, electrostatic collectors 25 and 32 in an embodiment to be described later) that is charged by friction at the time, and one of the friction body and the electrostatic collector is connected to the air supply path. It is characterized in that the friction body and the electrostatic collection body are charged by being moved using the flowing air as a power source, and the dust is collected by either the friction body or the electrostatic collection body.
With this configuration, the air flowing through the air supply path acts as a power source to move the friction body or the electrostatic collector, and the movement causes the friction body and the electrostatic collector to slide. Thereby, the friction body and the electrostatic collector are charged. Therefore, the friction body and the electrostatic trap can be charged without power other than the air flow.
[0008]
According to a third aspect of the present invention, in the second aspect, either one of the frictional body and the electrostatic collector (for example, a frictional body 24 in an embodiment described later) flows through the air supply path. Is rotatably mounted in the air supply path so as to be rotated by the air to be generated, and the other (for example, an electrostatic collector 25 in an embodiment described later) is fixed in the air supply path, The friction body and the electrostatic collection body are provided so as to be able to contact each other.
With this configuration, either the friction member or the electrostatic collector rotates while sliding on the other by being driven by the air flowing through the air supply path, and the friction at that time causes the friction member and the static collector to rotate. The collector is charged.
[0009]
According to a fourth aspect of the present invention, in the second aspect, one of the friction body and the electrostatic collecting body (for example, an electrostatic collecting body 32 in an embodiment described later) connects to the air supply passage. The other part (for example, a friction body 31 in an embodiment to be described later) is formed of a projection provided in the air supply path, and the friction body and the electrostatic collection body are formed in a thread-like shape fluttering by the flowing air. It is characterized by being provided so as to be able to contact each other.
With this configuration, one of the friction member and the electrostatic collector is swept by the air flowing through the air supply path and slides on the other, and the friction at that time charges the friction member and the electrostatic collector. I do.
[0010]
According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, a filtration type filter (for example, an embodiment described later) is provided in the air supply path downstream of the electrostatic collecting means. In which the filter 50) is provided.
With this configuration, since fine dust having electric charge is removed by the upstream electrostatic collecting means, it is sufficient that a large amount of dust can be removed by the downstream filtration type filter. And the pressure loss of the filter can be reduced. Further, when the dust having the electric charge collected by the electrostatic collecting means is attracted and aggregated by the mutual molecular force to form a large lump (agglomerated lump), and separated from the electrostatic collecting means, the aggregated lump is also formed. It is collected in a downstream filtration type filter.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of an air supply device for a fuel cell according to the present invention will be described with reference to the drawings of FIGS. This embodiment is an embodiment of a fuel cell air supply device mounted on a fuel cell vehicle.
[First Embodiment]
First, a first embodiment of an air supply device according to the present invention will be described with reference to FIGS.
FIG. 1 is a schematic configuration diagram of a fuel cell system including the air supply device 1.
The fuel cell 2 is formed by stacking a plurality of cells formed by sandwiching a solid polymer electrolyte membrane 2a made of a solid polymer ion exchange membrane or the like between an anode electrode 2b and a cathode electrode 2c from both sides (in FIG. 1, When only hydrogen gas is supplied as a fuel gas to the anode electrode 2b and air containing oxygen as an oxidant is supplied to the cathode electrode 2c, hydrogen ions generated by a catalytic reaction at the anode electrode 2b become After passing through the solid polymer electrolyte membrane 2a and moving to the cathode electrode 2c, an electrochemical reaction occurs with oxygen at the cathode electrode 2c to generate power and generate water.
[0012]
Hydrogen gas supplied from a hydrogen tank (not shown) is supplied to the anode electrode 2b of the fuel cell 2 through the hydrogen gas supply path 3, and unreacted hydrogen gas not consumed from the fuel cell 2 is turned off as anode gas 2b from the fuel cell 2. The hydrogen gas is discharged to the hydrogen gas circulation path 4 and returned to the hydrogen gas supply path 3 for circulation.
The air taken in from the atmosphere is pressurized by the compressor 5 and supplied to the cathode electrode 2c of the fuel cell 2 via the air supply path 6. The air supply path 6 is provided with an air purifying device 10 for removing dust in the air, and the air purified by the air purifying device 10 is supplied to the cathode 2 c of the fuel cell 2. After the air supplied to the fuel cell 2 is used for power generation, the air is discharged from the fuel cell 2 to the air discharge path 7 as a cathode off-gas and discharged to the atmosphere via a back pressure valve 8.
[0013]
Next, the air purification device 10 will be described in detail with reference to FIG.
The air purification device 10 is provided in a cylindrical tube 11 constituting the air supply passage 6 and is provided on an upstream side (closer to the compressor 5) of an electrostatic collection device (electrostatic collection means). The filter 20 includes a filtration type filter (hereinafter, referred to as a filtration filter) 50 installed on the downstream side (the side closer to the fuel cell 2).
The electrostatic collection device 20 includes an annular frame 22 rotatably supported on a tube 11 via a bearing 21, and a propeller 23 having an axial center coinciding with the axial center of the frame 22 is provided. The end of the blade is fixedly attached to the frame 22. A predetermined sealing structure (not shown) is provided so that air cannot flow between the tube 11 and the frame 22, and the air flowing through the tube 11 must be inside the frame 22. Is to be distributed. Therefore, when air is circulated through the tube 11, the flow of air drives the propeller 23 to rotate, and the frame 22 integrated with the propeller 23 rotates.
[0014]
At the downstream end of the frame 22, a disk-shaped friction body 24 made of a nonwoven fabric made of nylon is fixed while being electrically insulated from the frame 22.
Further, the electrostatic collecting device 20 includes a disk-shaped electrostatic collecting body 25 on the downstream side of the friction body 24. The electrostatic collection body 25 is made of a nonwoven fabric made of polyethylene, and is electrically insulated and fixed to the tube 11. The electrostatic collector 25 is arranged such that the downstream end surface of the friction body 24 contacts the upstream end surface of the electrostatic collector 25.
The filtration filter 50 installed downstream of the electrostatic collection device 20 is a general filtration type filter, and a relatively coarse filter is used.
[0015]
In the air purification device 10 configured as described above, when the air sucked from the atmosphere is pressurized by the compressor 5 and flows through the air supply path 6 toward the fuel cell 2, the air collection device 20 The frame 22 is rotated by the propeller 23, and the friction body 24 that rotates integrally with the frame 22 slides on the electrostatic collector 25. At this time, the friction between the friction body 24 and the electrostatic collection body 25 causes the friction body 24 and the electrostatic collection body 25 to be charged to polarities opposite to each other. It is attracted to one of the body 24 and the electrostatic collector 25 and collected.
In particular, in this embodiment, the friction body 24 is made of nylon, the electrostatic trap 25 is made of polyethylene, and silica and polyethylene are present in the air because they are easily charged to opposite polarities. Fine silica can be efficiently collected by the electrostatic collector 25, and silica in the air can be removed with high efficiency.
[0016]
Then, large dust and dust having no charge that cannot be removed by the electrostatic collection device 20 are collected by the downstream filtration filter 50. Further, when the dust collected by the electrostatic collector 25 is attracted and aggregated by the mutual molecular force to form a large lump (agglomerated lump) and separates from the electrostatic collector 25, the aggregated lump is also filtered downstream. It is collected by the filter 50.
As described above, according to the air purification device 10, fine dust having electric charge can be collected by the electrostatic collection device 20 on the upstream side, and large dust and dust having no electric charge can be collected by the electrostatic collection device 20 on the upstream side. Since the agglomerates separated from the device 20 can be collected by the downstream filtration filter 50, clean air from which dust has been removed can be supplied to the cathode electrode 2c of the fuel cell 2. As a result, the cathode electrode 2c does not become clogged due to the adhesion of dust, and it is possible to prevent a decrease in the output of the fuel cell 2 due to the clogging of the electrode. In particular, since the silica in the air is removed with high efficiency by the electrostatic collection device 20, it is possible to prevent the silica from adhering to the cathode electrode 2c and causing clogging.
[0017]
The upstream electrostatic collection device 20 that captures fine dust has a small pressure loss due to its structure, and the downstream filtration filter 50 that captures large dust has a coarse mesh, so that the pressure loss is small. Therefore, the pressure loss of the air purification device 10 as a whole can be reduced, and fine dust can also be removed.
Therefore, a pressure change in the air purification device 10 due to a change in the air volume due to the output variation of the fuel cell 2 is small, and the durability of the air purification device 10 can be increased.
Further, since the charging drive source of the electrostatic collection device 20 is an air flow generated by the compressor 5 to supply air to the fuel cell 2, no new energy source is required, and the device configuration is simplified. Can be
In addition, since the pressure loss of the air purification device 10 is small, the output required for the compressor 5 can be small, and the ratio of the power generated by the fuel cell 2 consumed by the compressor 5 can be reduced. And the driving output of the fuel cell vehicle can be increased and the cruising distance can be extended.
[0018]
[Second embodiment]
Next, a second embodiment of the air supply device according to the present invention will be described with reference to FIGS. 3 and 4. FIG.
The air purification device 10 according to the second embodiment differs from the air purification device according to the first embodiment in that the air purification device 10 includes a turbulence generation unit 40 and the configuration of the electrostatic collection device 20.
Hereinafter, the air purification device 10 according to the second embodiment will be described with reference to the cross-sectional view of FIG.
[0019]
The electrostatic collection device (electrostatic collection means) 20 is installed upstream of the filtration filter 50 in the tube 11, and the turbulence generator 40 is installed upstream of the electrostatic collection device 20.
The turbulence generator 40 is provided on the inner peripheral surface of the tube 11, and is composed of a number of protrusions 41 whose tips project toward the center of the tube 11.
The electrostatic collection device 20 includes a plurality of friction bodies 31 and a plurality of electrostatic collection bodies 32 attached to the inner peripheral surface of the tube 11. The friction body 31 is formed of a rigid nylon fiber, and has a protrusion fixed at the base end to the inner peripheral surface of the tube 11 and extending at the tip toward the center of the tube 11. The electrostatic collector 32 is formed of a flexible polyethylene fiber and has a thread shape. The base end is fixed to the inner peripheral surface of the tube 11 and the tip is a free end.
The friction body 31 and the electrostatic collection body 32 are provided in a predetermined area downstream of the turbulence generating section 40, and the electrostatic collection body 32 contacts the friction body 31 when the electrostatic collection body 32 flies in the wind. The length of the collector 32 is set.
[0020]
According to the air purification device 10 configured as described above, when the air flowing through the tube 11 passes through the turbulence generator 40, turbulence is generated, and the turbulence of the air causes the electrostatic collector 32 to violently flow. And contacts the friction body 31 and slides. The friction at this time causes the friction body 31 and the electrostatic collection body 32 to be charged to polarities opposite to each other, so that fine dust having a charge existing in the air is charged to either the friction body 31 or the electrostatic collection body 32. Attracted and collected. In particular, since turbulence is generated in the air, dust, which is particles in the air, is likely to collide with the friction body 31 and the electrostatic collection body 32, so that the collection effect is large.
Also in this embodiment, the friction body 31 is made of nylon, the electrostatic trap 32 is made of polyethylene, and silica and polyethylene are easily charged to opposite polarities. Silica can be efficiently collected by the electrostatic collector 32, and silica in the air can be removed with high efficiency.
[0021]
Then, large dust and dust having no charge that cannot be removed by the electrostatic collection device 20 are collected by the downstream filtration filter 50. Dust collected by the friction body 31 and the electrostatic collection body 32 may be scraped off by the contact between the friction body 31 and the electrostatic collection body 32. However, they are attracted and coagulated by mutual molecular force. As a result, a large lump (agglomerated lump) is collected by the downstream filtration filter 50.
As described above, also with the air purification device 10 according to the second embodiment, fine dust having electric charge can be collected by the electrostatic collection device 20 on the upstream side, and large dust and dust having no electric charge can be collected. Since the aggregate separated from the electrostatic collection device 20 can be collected by the downstream filtration filter 50, clean air from which dust has been removed can be supplied to the cathode electrode 2 c of the fuel cell 2. . As a result, the cathode electrode 2c does not become clogged due to the adhesion of dust, and it is possible to prevent a decrease in the output of the fuel cell 2 due to the clogging of the electrode. In particular, since the silica in the air is removed with high efficiency by the electrostatic collection device 20, it is possible to prevent the silica from adhering to the cathode electrode 2c and causing clogging.
[0022]
The upstream electrostatic collection device 20 that captures fine dust has a small pressure loss due to its structure, and the downstream filtration filter 50 that captures large dust has a coarse mesh, so that the pressure loss is small. Therefore, the pressure loss of the air purification device 10 as a whole can be reduced, and fine dust can also be removed.
Therefore, a pressure change in the air purification device 10 due to a change in the air volume due to the output variation of the fuel cell 2 is small, and the durability of the air purification device 10 can be increased.
Further, since the charging drive source of the electrostatic collection device 20 is an air flow generated by the compressor 5 to supply air to the fuel cell 2, no new energy source is required, and the device configuration is simplified. Can be
In addition, since the pressure loss of the air purification device 10 is small, the output required for the compressor 5 can be small, and the ratio of the power generated by the fuel cell 2 consumed by the compressor 5 can be reduced. And the driving output of the fuel cell vehicle can be increased and the cruising distance can be extended.
[0023]
The turbulence generator 40 of the air purification device 10 according to the second embodiment can be configured by a cyclone 42 as shown in FIG. The cyclone 42 not only functions to cause turbulence in the air, but also functions as a centrifugal separator using a swirling flow. Therefore, the cyclone 42 can remove large dust in the air, and the load on the filter 50 can be reduced. Can be reduced.
[0024]
[Other embodiments]
Note that the present invention is not limited to the above-described embodiment.
For example, the electrostatic collection means is not limited in structure as long as it can collect charged dust. In addition to charging the frictional body and the electrostatic collection body by friction, the electrostatic collection means can charge the electrostatic collection means. The one to be applied can also be suitably used.
Further, the material of the friction body and the electrostatic collector constituting the electrostatic collecting means for collecting the silica can be preferably a combination of nylon and polyethylene, but is not limited thereto. An appropriate material can be adopted depending on the electric charge of the dust.
Further, in the first embodiment, the electrostatic collector is fixed to the air supply path, and the friction body is mounted so as to be rotated by air flowing through the air supply path. The friction body may be fixed, and the electrostatic collector may be rotated by air.
Further, in the second embodiment, the friction body is formed to be rigid, and the electrostatic collecting body is formed in a string shape so as to flutter by the air flowing through the air supply path. May be formed rigidly and fixed to the air supply path, and the friction body may be formed in a thread shape so as to flow into the air.
[0025]
【The invention's effect】
As described above, according to the first aspect of the present invention, fine dust having a charge contained in the atmosphere, such as silica, can be removed by the electrostatic collecting means. Of the fuel cell can be prevented from being supplied to the cathode electrode, and the output of the fuel cell can be prevented from lowering due to dust adhesion. Further, since the electrostatic collection means has a small pressure loss, the energy required for supplying air to the fuel cell can be reduced, and the energy efficiency of the fuel cell is improved.
According to the second to fourth aspects of the present invention, the friction body and the electrostatic collector can be charged without power other than the air flow, so that a new energy source is not required and the apparatus configuration is simplified. It has the effect of becoming.
According to the fifth aspect of the present invention, fine dust having electric charges is removed by the upstream electrostatic collecting means, and the dust having electric charges collected by the electrostatic collecting means is separated from each other by the intermolecular force. When the particles are attracted and aggregated to form a large lump (agglomerated lump) and separate from the electrostatic collecting means, the lump is also collected by the downstream filtration type filter. Can be removed, and the mesh of the filter can be coarsened, and the pressure loss of the filter can be reduced.
[Brief description of the drawings]
FIG. 1 is a configuration diagram in a first embodiment of a fuel cell system including an air supply device according to the present invention.
FIG. 2 is a sectional view of a main part of the air supply device in the embodiment.
FIG. 3 is a sectional view of a main part of an air supply device according to a second embodiment.
FIG. 4 is a sectional view of a main part of a modification of the air supply device according to the second embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Air supply device 2 Fuel cell 2b Anode electrode 2c Cathode electrode 6 Air supply path 20 Electrostatic collection device (electrostatic collection means)
24 Friction body 25 Electrostatic collection body 31 Friction body 32 Electrostatic collection body 50 Filtration filter (filtration type filter)

Claims (5)

A fuel cell in which air as an oxidant is supplied to a cathode electrode and fuel gas is supplied to an anode electrode to generate power,
An air supply path for supplying air to the cathode electrode of the fuel cell,
Provided in the air supply path, electrostatic collection means for collecting the dust by charging the opposite polarity to the charge of the dust to be collected,
An air supply device for a fuel cell, comprising: The electrostatic collection means includes a friction body and an electrostatic collection body that is charged by friction when the friction body comes into contact with the friction body, and one of the friction body and the electrostatic collection body is connected to the air supply path. The friction body and the electrostatic collector are charged by being moved by using the air flowing through as a power source, and the dust is collected by either the friction body or the electrostatic collector. An air supply device for a fuel cell according to claim 1. Either the friction body or the electrostatic collector is rotatably mounted in the air supply path so as to be rotated by air flowing through the air supply path, and the other is provided in the air supply path. The air supply device for a fuel cell according to claim 2, wherein the air supply device is fixed, and the friction body and the electrostatic collection body are provided so as to be able to contact each other. Either the friction body or the electrostatic collection body has a thread-like shape fluttering by air flowing through the air supply path, and the other is configured by a protrusion provided in the air supply path, The air supply device for a fuel cell according to claim 2, wherein the electrostatic collectors are provided so as to be able to contact each other. The air supply device for a fuel cell according to any one of claims 1 to 4, wherein a filter of a filtration type is provided in the air supply path downstream of the electrostatic collection means.

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