JP2010140655A - Fuel cell device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell device capable of equalizing temperature distribution at a downstream side of the surface of a cathode, and suppressing the generation of dew drops at power generation. <P>SOLUTION: The fuel cell device enabled to exhaust air by a blasting means from an air supply channel 1 at one of side faces of a stack 3 to an air exhaust channel 5 at the other side face has a through-hole penetrating the air supply channel and the air exhaust channel at either side face of the stack for supplying air to a cathode. The through-hole, when the stack is fitted so that the surface of the cathode is in a direction vertical to a horizontal direction in which air is blasted in a state that the air is blasted in a horizontal direction by the blasting means, the air is free in moving in a vertical direction on the surface of the cathode, and when the air from the air supply channel moves toward the air exhaust channel, the air above the surface of the cathode in a vertical direction hardly moves than air at a lower side. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel cell device. In particular, the present invention relates to a fuel cell device configured to supply air to a fuel cell stack provided with an air discharge path.

In a fuel cell, a fuel such as hydrogen or alcohol is electrochemically reacted with oxygen to directly convert the chemical energy of the fuel into electric energy.
Among fuel cells, a polymer electrolyte fuel cell using a solid polymer as an electrolyte membrane operates near room temperature and has low noise during operation.
For this reason, solid polymer fuel cells are being developed for a wide range of uses such as power supplies for portable devices, power supplies for fuel cell vehicles, and distributed power supplies for home use.

When such a fuel cell is used as a power source for a portable device, methanol, ethanol, or an aqueous solution thereof, which is easy to handle, is often used as the fuel.
Usually, oxygen in the air is used as the oxygen necessary for the reaction.
The power generation reaction of the fuel cell occurs on a cell composed of an anode, a cathode, and an electrolyte membrane.
Due to the power generation reaction, the voltage generated in one cell is as small as about 1 V or less. Therefore, in a fuel cell for a portable device power source, a plurality of cells are often stacked and used in a so-called stack form.
In the case of stacking, a blowing means such as a fan or a pump is generally used to supply air necessary for power generation reaction to each cell.

FIG. 11 shows a schematic diagram of a stack and an air supply method created by the prior art.
In the figure, reference numeral 103 denotes a stack, which is composed of a plurality of cells 104.
101 is an air supply path, and 102 is an air supply port. Reference numeral 105 denotes an air discharge path, and 107 denotes an air discharge port.
Reference numeral 106 denotes an air blowing means storage unit in which air blowing means such as a fan is installed.
Air is taken into the air supply path from the air supply port by the action of the air blowing means, moves to the air discharge path through the air flow path provided in the cathode portion of each cell, and is discharged from the air discharge port. .

Some fuel cells for portable devices have a fixed orientation when in use, such as being installed on a desk.
When an alcohol fuel such as methanol is used as the fuel, carbon dioxide is generated on the anode side during power generation.
When the installation direction of the fuel cell in use is determined, as shown in FIG. 11, it is known that discharge of carbon dioxide bubbles is facilitated by arranging the cells in a vertical orientation.
Here, the vertical orientation specifically refers to the state in which the air is blown in the horizontal direction from the air supply path to the air discharge path by the blowing means, and the surface of the cathode portion is in the horizontal direction of the blowing. It is in a state where it is installed so as to be perpendicular to the direction.
Further, when it is necessary to reduce the shape of the fuel cell in consideration of the shape of the entire device when used in combination with a portable device, the air supply port and the discharge port are stacked as shown in FIG. It is convenient to install on both sides.

In general, a part of the electric power generated by the fuel cell is used as the electric power for moving the blowing means.
Therefore, in order to use the electric power generated by the fuel cell as effectively as possible to move an external portable device, it is necessary to supply air to the cathode of each cell with a blower that consumes as little power as possible.
Therefore, in order to minimize the pressure loss during air movement, the cathode surface has a gap-like structure that allows air to freely pass through. As the blowing means, a fan or blower that can blow air with low power consumption is used. There is a way.
As one of such methods, Patent Document 1 discloses a fuel cell system in which ducts are provided at the upper and lower portions of a stack and air is evenly supplied to each cell.
Further, Patent Document 2 discloses a power generator that provides air suction means on the discharge side of the air flow path of the cathode and promotes the evaporation of water when water aggregates at the cathode.
JP 2007-115696 A JP 2001-185181 A

As shown in FIG. 11, when an air supply path and an air discharge path are provided on both sides of the stack and the fuel cell is used in the direction shown in this figure, it is necessary to blow air in the horizontal direction against the cathode surface of the cell. There is.
However, when air is supplied by providing a gap in the cathode surface of each cell in the stack, condensation occurs in the lower part on the downstream side of the cathode where the humidity in the air is high and the temperature is relatively low The problem that it becomes easy to do arises.

Hereinafter, these will be described in more detail with reference to the drawings.
FIG. 12 shows a schematic diagram of the cathode surface of the fuel cell of FIG.
In FIG. 12, the same components as those in FIG. 11 are denoted by the same reference numerals, and the description of the overlapping parts is omitted.
In the figure, reference numeral 108 denotes a cathode surface. When air is supplied to the cathode surface by the blowing means, the air moves from the left side to the right side in the figure.
Water is generated on the cathode surface by the power generation reaction, and the cathode side surface of the electrolyte membrane is wet with moisture diffused from the anode side, so the humidity of the air is from upstream (air supply path side) to downstream (air discharge path side) As the cathode surface is moved toward
Since the cathode surface generates heat during the power generation reaction, the air is heated as it moves on the cathode surface, and the temperature on the upper side of the cathode surface becomes higher than that on the lower side due to convection. Specifically, as shown in FIG. 12, the temperatures on the A and C sides of the cathode surface 108 are higher than those on the B and D sides.
Further, the humidity of air in the vicinity of A and B on the upstream cathode surface 108 is relatively small, and the humidity in the vicinity of C and D on the downstream cathode surface 108 is high.
As a result, there arises a problem that water is condensed near the relatively low temperature D on the downstream side including air with high humidity, and condensation is likely to occur.

Once such dew condensation occurs, it is difficult to supply air necessary for the reaction, so that the power generation reaction in the vicinity thereof is hindered.
As a result, the heat of reaction becomes small, the temperature of the part falls, and it becomes easy to condense.
Neither the fuel cell system of Patent Literature 1 nor the power generation device of Patent Literature 2 can suppress temperature variations such that the temperature on the upper side becomes higher than that on the lower side on the downstream side of the cathode surface.
For this reason, it is difficult to solve the problem that condensation is likely to occur on the downstream side during power generation.

  In view of the above problems, an object of the present invention is to provide a fuel cell device that can make the temperature distribution in the downstream portion of the cathode surface uniform and suppress the occurrence of condensation during power generation. is there.

In order to solve the above-described problems, the present invention provides a fuel cell device configured as follows.
The fuel cell device of the present invention includes a stack composed of one or a plurality of cells including a cathode portion on one surface side of an electrolyte membrane and an anode portion on the other surface side,
A fuel cell device capable of discharging air by air blowing means from an air supply path provided on one side surface on both side surfaces of the stack to an air discharge path provided on the other side surface,
A through hole penetrating between the air supply path and the air discharge path on both side surfaces of the stack for supplying air to the cathode portion;
The through hole is formed so that the surface of the cathode portion is perpendicular to the horizontal direction in which the air is blown in a state where the air is blown in the horizontal direction by the blowing means. When installed
The air is configured to be movable in the vertical direction on the surface of the cathode part,
The air discharge path has a structure in which, when the air from the air supply path moves to the air discharge path, the upper air in the vertical direction on the surface of the cathode portion is less likely to move than the lower air. It is characterized by having.
Moreover, the fuel cell device of the present invention is characterized in that the air discharge path has a structure with a shape in which a width in a horizontal direction in which the air is blown is changed.
The fuel cell device according to the present invention is characterized in that the horizontal width of the air discharge path is increased as it goes from the upper side to the lower side in the vertical direction.
Further, the fuel cell device of the present invention has a structure in which the air discharge path can be formed by a control plate that can change the direction of the air discharge path provided in the air discharge cover. ,
When the stack is installed in a first state in which the surface of the cathode portion is perpendicular to the horizontal direction in which the air is blown, the air in the air discharge path is blown by the direction of the control plate. While the horizontal width is configured to be variable,
When the stack is installed in the second state rotated 90 degrees from the first state, the horizontal width in which the air is blown in the air discharge path does not change depending on the direction of the control plate It is said that it is said.
Further, in the fuel cell device of the present invention, when the stack is installed in the first state, a larger width is formed as the horizontal width of the air discharge path is changed from the upper side to the lower side in the vertical direction. It is characterized by being.
The fuel cell device of the present invention is characterized in that the change of the direction of the control plate can be automatically changed by gravity.
The fuel cell device of the present invention is characterized in that the direction of the control plate can be changed manually.

  ADVANTAGE OF THE INVENTION According to this invention, the temperature distribution in the downstream part of a cathode surface can be equalize | homogenized, and the fuel cell apparatus which becomes possible [suppressing generation | occurrence | production of dew condensation at the time of electric power generation] is realizable.

Next, an embodiment of the present invention will be described.
(First embodiment)
As a first embodiment of the present invention, air is supplied from the air supply path on one side surface to the air discharge path on the other side surface of the stack composed of one or a plurality of cells by air blowing means. One configuration example of the fuel cell device that can be discharged will be described.
In FIG. 1, the schematic diagram for demonstrating the structural example of the fuel cell apparatus in 1st embodiment of this invention is shown.
In the figure, 1 is an air supply path, and 2 is an air supply port.
Reference numeral 3 denotes a stack, which is composed of a plurality of cells 4.
5 is an air discharge path, and 7 is an air discharge port.
Reference numeral 6 denotes a blower means storage unit in which a blower means such as a fan is installed.

In the fuel cell of the present embodiment, the stack is used in a vertically installed state as shown in FIG.
Here, as described above, the vertical installation refers to the surface of the cathode portion of the cell 4 in a state where air is blown in the horizontal direction from the air supply path 1 to the air discharge path 5 by the blowing means. Indicates a state of being installed so as to be perpendicular to the horizontal direction of the air blowing.
In the present embodiment, the air discharge path 5 is formed in a triangular prism shape as shown in FIG.
The width in the horizontal direction of the air discharge path 5 is made to increase as it proceeds from the upper part to the lower part of the cell.
In order to operate the fuel cell, a so-called auxiliary machine such as a pump for supplying fuel or a power extraction circuit from the stack is required.

FIG. 2 is a schematic diagram for explaining the flow of air to the cathode portion of each cell in the stack, and is a view of the stack of FIG. 1 as viewed from above.
In the figure, 8 is an end plate, 9 is an anode part of the cell, 10 is a cathode part of the cell, and 11 is a bipolar plate.
The cell includes an anode part, a cathode part, an electrolyte membrane (not shown in FIG. 2) sandwiched between the anode part and the cathode part, and a bipolar plate.
Further, as will be described in detail with reference to FIG. 3, the cell is provided with a through-hole penetrating between the air supply path 1 and the air discharge path 5 on both side surfaces of the stack for supplying air to the cathode portion 10. It is said that.
Reference numeral 12 denotes air blowing means, which is installed in the sending means storage section.
The air taken into the air supply path from the air supply port by the function of the air blowing means moves to the air discharge path through the through hole provided in the cathode portion of each cell, and is discharged from the air discharge port.

FIG. 3 is a schematic view for explaining the details of the cell structure in the first embodiment of the present invention, and is a view of the stack of FIG. 1 as viewed from the side on the air supply path side.
In the figure, 17 is an electrolyte membrane, 16 is a cathode catalyst electrode, and 18 is an anode catalyst electrode.
A cathode air supply unit 14 supplies air to the cathode.
The cathode part described in FIG. 2 is composed of a cathode electrode and a cathode air supply part, and the anode part described in FIG. 2 is composed of an anode catalyst electrode.
A flow path for flowing a fuel solution is formed inside the bipolar plate 11 so that fuel is supplied to the anode catalyst electrode.
The cathode catalyst electrode is composed of a cathode catalyst, a gas diffusion layer, and current collecting means, and the anode catalyst electrode is composed of an anode catalyst, a gas diffusion layer, and current collecting means.
Since each catalyst electrode can be prepared by a known method, detailed description thereof is omitted.
A conductive portion 15 made of a conductive material electrically connects the cathode catalyst electrode and the bipolar plate.
Reference numeral 13 denotes a case that covers the upper side and the lower side of the stack.
The cathode air supply unit 14 is formed by a through-hole penetrating between the air supply path and the air discharge path on both side surfaces of the stack.
Inside the through hole, the cathode air supply section is formed so that air can move in the vertical direction along the cathode surface.
That is, when the through hole is installed so that the air is blown in the horizontal direction by the blowing means so that the surface of the cathode portion is perpendicular to the horizontal direction of the blowing, The air is formed to be movable in the vertical direction on the surface of the cathode portion.
Such a through hole can be easily created by creating a gap through which air can pass through the cathode surface.

Next, in the fuel cell of the present embodiment, a mechanism in which the surface temperature becomes uniform on the downstream side of the cathode surface of the cell will be described.
FIG. 4 is a schematic diagram for explaining the air flow on the cathode surface when the stack is viewed from the side surface on the air discharge port side. A, B, C, and D in FIG. 4 correspond to A, B, C, and D described with reference to FIG.
When air is supplied to the cathode surface by the air blowing means, the air moves from the left side to the right side in the figure, but since the upper width of the air discharge path 5 is reduced, the air on the downstream and upper sides of the cathode surface is It cannot move enough to the air discharge path.
Therefore, on the downstream side of the cathode surface, a part of the upper air moves downward and flows into the air discharge path.
As a result, the high temperature air on the upper side is supplied to the lower side of the cathode surface, the temperature on the lower side (in the vicinity of D) rises, and water condensation can be suppressed in the vicinity of D, thereby suppressing the occurrence of condensation. can do.

In the present embodiment, the air discharge path 5 has been described as having a triangular prism shape as shown in FIG. 1, but the present invention is not limited to such a configuration.
For example, other shapes may be used as long as the width in the horizontal direction in which the air is blown increases from the upper side to the lower side in the vertical direction.
If the width is changed in this way, the air discharge path is configured such that when the air from the air supply path moves to the air discharge path, the upper air in the vertical direction on the surface of the cathode portion is Thus, it is possible to make the structure less likely to move than the lower air.

Examples of structures having a shape in which the width in the horizontal direction in which the air is blown are changed are shown in FIGS. 5, 6, 7, and 8.
FIG. 5 is a schematic view when the air discharge path has a columnar shape with a fan-shaped air discharge surface. FIG. 6 shows the air flow on the cathode surface when the stack is viewed from the side on the air discharge side. It is a schematic diagram for demonstrating a flow.
FIG. 7 is a schematic view when the air discharge duct has a columnar shape with a concave triangle as shown in the figure, and FIG. 8 is a view from the front.
5 and 7, in the same principle as in FIG. 1, on the downstream side of the cathode surface, a part of the upper air moves to the lower part, so that the temperature of the lower part rises and the cathode The temperature in the vicinity of C and D on the surface can be made uniform.
Thereby, it becomes possible to suppress the occurrence of condensation near D.
As can be seen from the cross-sectional shape of the air discharge duct, the rate of air movement from the upper part of the cell to the lower part increases in the order of FIG. 5, FIG. 1, and FIG.
In the embodiment of FIG. 1, the air blowing means is provided on the air discharge port side. However, as shown in FIG. 7, the air blowing means may be provided on the air supply port side.

(Second embodiment)
Next, as a second embodiment of the present invention, unlike the first embodiment, the air discharge path is provided by a control plate provided in the air discharge cover and capable of changing the orientation. A configuration example of a fuel cell device having a structure capable of forming an air discharge path will be described.
FIG. 9 is a schematic diagram for explaining a configuration example of a fuel cell device having a structure including an air discharge duct cover according to the second embodiment of the present invention.
In FIG. 9, the same number is attached | subjected to the same component as 1st embodiment, and description of the overlapping part is abbreviate | omitted.
In the figure, 22 is a discharge duct cover, and 20 is a control plate provided in the discharge duct cover.
The control plate is formed so that the direction can be changed around the rotation shaft 19, and is configured such that the air discharge flow path in the discharge duct cover changes depending on the direction of the control plate. 21 is a weight attached to the control plate. By this weight, the control plate on the side where the weight is attached to the rotating shaft becomes heavy, and the direction of the control plate automatically changes according to the direction of the stack by the force of gravity.

FIG. 10 is a schematic diagram for explaining a form in which the shape of the air discharge path in the air discharge duct cover in the second embodiment of the present invention is changed, and the stack in FIG. 9 is a side surface on the air outlet side. It is a figure when it sees from.
First, a case where the stack is installed as in the installation form A shown in FIG. This is a case where the stack is installed in a first state where the surface of the cathode portion is perpendicular to the horizontal direction in which the air is blown.
In this case, the control plate is tilted downward (in the direction of gravity) with the rotation axis as the center, and as shown in the figure, the air discharge path 5 surrounded by the control plate and the discharge duct cover is formed. Is done.
Thus, by configuring the horizontal width in which the air is blown in the air discharge path according to the orientation of the control plate, the air discharge path has the same shape as the first embodiment. can do.
This prevents the temperature distribution on the downstream side of the cathode surface of the cell from becoming non-uniform during the power generation of the fuel cell based on the same principle as described in the first embodiment. It becomes possible to suppress the aggregation of water.

Next, the case of installation as in the installation form B shown in FIG. 10B will be described. This is a case where the stack is installed in a second state rotated 90 degrees clockwise from the first state, and a case where the stack of FIG. 10A is rotated 90 degrees clockwise. .
In the case of this installation form, the control plate is oriented vertically as shown in the figure.
That is, an air discharge path is formed in which the width in the horizontal direction in which the air is blown in the air discharge path does not change depending on the direction of the control plate.
The air supplied from the air supply path 1 flows through the cathode surface 16 and is discharged to the air discharge path 5.
As shown in FIG. 10B, when air is supplied along the cathode surface from the upper side to the lower side in the direction of gravity, the temperature due to convection on the downstream side of the cell as described in FIG. Non-uniformity does not occur.
That is, in the case of the installation form shown in FIG. 10B, the air discharge passages are evenly provided on the left and right as viewed in the figure, and the air flows evenly on the left and right sides of the cathode surface.
Therefore, in the case of this installation form, by supplying air evenly to the cell surface and making the temperature on the downstream side of the cell uniform, the power generation on the cell surface can be made uniform. .

10C is a case where the stack of FIG. 10B is further rotated 90 degrees clockwise.
In this installation mode, the control plate is centered around the rotation axis, and the part away from the stack is tilted downward (in the direction of gravity). As shown in the figure, the control plate is surrounded by the control plate and the discharge duct cover. A path 5 is formed.
This air discharge path has the same shape as that of the first embodiment, and the temperature on the downstream side of the cathode surface of the cell during power generation of the fuel cell is based on the same principle as described in the first embodiment. It can suppress that distribution becomes non-uniform | heterogenous.
Thereby, it becomes possible to suppress aggregation of water in the lower portion on the downstream side of the cell. By providing a control plate that can rotate depending on the direction of the stack in the discharge duct cover as in the present embodiment, an air discharge passage having an optimal shape can always be formed even if the stack installation direction changes.
In the present embodiment, the change of the direction of the control plate is configured to be automatically changeable by gravity, but is not limited to such a configuration.
For example, it may be configured to be manually changeable.

According to the configuration of the embodiment of the present invention described above, a part of the air flow at the higher temperature on the downstream side of the cathode surface of the cell due to the change in the air flow accompanying the shape of the air discharge path. Can flow toward the air at the lower temperature.
As a result, the temperature distribution on the downstream side of the cathode surface can be made uniform during power generation, and it is possible to realize a fuel cell device that can efficiently generate power while suppressing the aggregation of water on the cell surface. .
Moreover, since the air flow path on the cathode surface can be formed with a structure with very little pressure loss, an air blowing means with low power consumption can be used.
Therefore, it is possible to reduce the electric power consumed for moving the air blowing means, and it is possible to use the output of the fuel cell more effectively to move an external device such as a portable device.

It is a schematic diagram for demonstrating the structural example of the fuel cell apparatus in 1st embodiment of this invention. It is a schematic diagram for demonstrating the flow of the air to the cathode part in 1st embodiment of this invention. It is a schematic diagram for demonstrating the detail of the cell structure in 1st embodiment of this invention. It is a schematic diagram explaining the cathode side surface of the cell in 1st embodiment of this invention. It is a schematic diagram which shows the structure of the 2nd air exhaust path in 1st embodiment of this invention. It is a schematic diagram explaining the cathode side surface of the 2nd air air discharge path and cell in 1st embodiment of this invention. It is a schematic diagram which shows the structure of the 3rd air exhaust path in 1st embodiment of this invention. It is a schematic diagram explaining the cathode side surface of the 3rd air air discharge path and cell in 1st embodiment of this invention. It is a schematic diagram for demonstrating the structural example of the fuel cell apparatus of the structure provided with the air exhaust duct cover in 2nd embodiment of this invention. It is a schematic diagram for demonstrating the form which changes the shape of the air exhaust path in the air exhaust duct cover in 2nd embodiment of this invention. It is a schematic diagram for demonstrating the fuel cell apparatus which provided the air discharge path by a prior art, and was made to supply air to a fuel cell stack. It is a schematic diagram for demonstrating the state of the cathode side surface in a fuel cell at the time of supplying air to the fuel cell stack which provided the air discharge path by a prior art.

Explanation of symbols

1: Air supply path 2: Air supply port 3: Stack 4: Cell 5: Air discharge path 6: Air blower storage unit 7: Air discharge port 8: End plate 9: Anode unit 10: Cathode unit 11: Bipolar plate 12: Air blowing means 13: Case 14: Cathode air supply part 15: Conductive part 16: Cathode catalyst electrode (cathode surface)
17: Electrolyte membrane 18: Anode catalyst electrode 19: Rotating shaft 20: Control plate 21: Weight 22: Exhaust duct cover 101: Air supply path 102: Air supply port 103: Stack 104: Cell 105: Air exhaust path 106: Air blowing Means storage unit 107: air outlet

Claims (7)

A stack composed of one or more cells each having a cathode portion on one surface side of the electrolyte membrane and an anode portion on the other surface side;
A fuel cell device capable of discharging air by air blowing means from an air supply path provided on one side surface on both side surfaces of the stack to an air discharge path provided on the other side surface,
A through hole penetrating between the air supply path and the air discharge path on both side surfaces of the stack for supplying air to the cathode portion;
The through hole is formed so that the surface of the cathode portion is perpendicular to the horizontal direction in which the air is blown in a state where the air is blown in the horizontal direction by the blowing means. When installed
The air is configured to be movable in the vertical direction on the surface of the cathode part,
The air discharge path has a structure in which when the air from the air supply path moves to the air discharge path, the upper air in the vertical direction on the surface of the cathode portion is less likely to move than the lower air. A fuel cell device comprising:   2. The fuel cell device according to claim 1, wherein the air discharge path has a structure with a shape in which a width in a horizontal direction in which the air is blown is changed.   3. The fuel cell device according to claim 2, wherein a width of the air discharge path in the horizontal direction increases from the upper side to the lower side in the vertical direction. The air discharge path has a structure in which the air discharge path can be formed by a control plate provided in the air discharge cover and capable of changing the orientation.
When the stack is installed in a first state in which the surface of the cathode portion is perpendicular to the horizontal direction in which the air is blown, the air in the air discharge passage is blown by the direction of the control plate. While the horizontal width is configured to be variable,
When the stack is installed in the second state rotated 90 degrees from the first state, the horizontal width in which the air is blown in the air discharge path does not change depending on the direction of the control plate The fuel cell device according to claim 1, wherein   5. When the stack is installed in the first state, a larger width is formed as the horizontal width of the air discharge path is changed from the upper side to the lower side in the vertical direction. The fuel cell device described in 1.   The fuel cell device according to claim 4 or 5, wherein the change of the orientation of the control plate is configured to be automatically changeable by gravity.   6. The fuel cell device according to claim 4, wherein the direction of the control plate can be changed manually.

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